| 1. |
- De Toro, Alfredo, et al.
(författare)
-
Effects of extreme weather on yield of major arable crops in Sweden
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Yield data for a series of years on the main crops grown in Sweden were collected and summarised in order to identify years with extremely low yield, determine their frequency and risk level and relate these to weather data in order to identify weather events leading to large yield reductions. Annual yield data at county level for cereals, field beans, oilseed rape, potatoes and temporary grasses were taken from official statistics for the period 1965-2014. For the period 2005-2012, crop yield data on farm level were also available from official statistics. In addition, yield data for cereals and temporary grasses being studied in long-term experiments (more than 40 years) located in four different agro-ecological zones of Sweden were considered. Daily temperature and precipitation data for each of the 21 counties in Sweden during the period 1961-2012 were downloaded from the official Swedish weather data website. In general, yield reductions were higher in northern than in southern counties and higher for spring cereals than winter cereals. Oats, spring rape and potatoes were the crops with the highest yield variation at county level. The frequency of a 30% yield reduction at county level was very low or close to zero in those counties with widespread cereal production, but large reductions occurred in individual years and certain counties (e.g. -80% in Norrbotten county in 1987). Close agreement between annual area of non-harvested crops and a 30% yield reduction was observed for certain years, crops and counties. The northern counties had on average 4-11% non-harvested crop area, with Norrbotten county having the highest values. The non-harvested area of cereals in southern counties was on average 0-2%. The risk of severe crop losses on farm level was around 10%, although in a few cases the risk was 25%, depending on the county. More specifically, the overall risk among the counties for individual farms of obtaining 30% lower yield for winter wheat was 5-20%, for spring wheat 5-20%, for rye 5-10% and for spring barley 5-25%. The corresponding risk of obtaining 50% lower yield for oats was 5-20%. The yield data for individual farms showed large variations, even in years with ‘favourable’ weather conditions. In most years, yield on the lower 10th percentile of farms was less than half the average yield at county level. Winter wheat showed the lowest variation in southern counties and oats and spring rape the highest. Farm-level yield variations were also much higher in Norrbotten county than in southern counties. This large yield variation was confirmed by data from the long-term crop experiments, in which yield reductions exceeding 30% occurred in 5-18% of years (i.e. 2-8 years in the period 1965-2010). Most years with the lowest yield were associated with a prolonged dry period (<20 mm precipitation over 40 days) and/or a high level of precipitation during the harvesting period (>100 mm during August). However, attempts to correlate county average yields with indices based only on daily temperature and precipitation gave poor and inconsistent results. Similar results were obtained using yield data from the long-term experiments and indices based solely on precipitation. The large yield variations between individual farms, the heterogeneity of crop responses to Scandinavian weather conditions and the limitations of yield prediction models in terms of detailed input data and result accuracy indicate that yield reductions should be measured on farm level. Within the study period, precipitation during summer months appeared to increase over time, particularly in 25% of years in southern Sweden. If this situation persists, it will have conflicting effects on crop production, by reducing the risk of drought periods and increasing the risk of rainy harvesting periods.
|
|
| 2. |
- Ahlgren, Serina, et al.
(författare)
-
Det svenska jordbrukets framtida drivmedelsförsörjning
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med detta arbete är att visa på möjligheter för det svenska jordbruket att bli försörjt med drivmedel även i en framtid, när oljan har blivit för dyr eller sällsynt för att kunna användas i tillräcklig omfattning. Detta projekt studerar möjligheterna att ersätta fossil diesel med första och andra generationens förnybara drivmedel, och omfattar drivmedel från råvaror med ursprung i både jord- och skogsbruk. De drivmedel som studeras är etanol, rapsmetylester (RME), biogas, Fischer-Tropsch diesel (FTD), dimetyleter (DME) och metanol. Arealbehov, energibalans och kostnader har beräknats. Studien visar att det finns tillräckligt med arealer i Sverige för att lantbruket ska kunna bli självförsörjande med drivmedel. För de drivmedel som baseras på grödor framförallt första generationens drivmedel) kommer dock mängden mat som är möjlig att producera att minska. Andra generationens drivmedel kan med fördel produceras från biprodukter som halm och matproduktionen behöver då inte minskas
|
|
| 3. |
|
|
| 4. |
- Ahlgren, Serina, et al.
(författare)
-
Produktion av kvävegödsel baserad på förnybar energi - En översikt av teknik, miljöeffekter och ekonomi för några alternativ
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Mineral nitrogen fertilizer is one of the main reasons for the high yields in modern, industrial agriculture. There is currently no production of mineral nitrogen fertilizer in Sweden – the entire demand is met by imports from abroad. Global production is at present based on fossil resources, which are used both as raw materials for the production and as energy to fuel the process. We are thus dependent on foreign fossil resources – as fuel and fertilizer – for our agricultural production. However, nitrogen fertilizers could be produced using renewable resources, which could pave the way for a more sustainable production of food and bioenergy. This report aims to describe and compare different production process options for the production of nitrogen fertilizers based on renewable energy sources. The report presents estimated production costs based on techno-economic modelling, environmental impact of renewable fertilizer based on life cycle assessments, and an overview of potential risks and benefits of renewable fertilizers. The report can be read as a feasibility study, which can be used to provide information for actors who are interested in supporting the development of renewable fertilizers. The results show that the cost of producing nitrogen fertilizer depends on the choice of production process technology and that some technologies benefit from economies of scale. Among the studied options, the production cost for renewable nitrogen fertilizer was lowest when produced through thermochemical gasification of biomass. The cost for this option was estimated to 11-14 SEK/kg N, which can be compared with the current price of about 10 SEK/kg N. However, gasification of biomass is not yet a commercially available technology but rather a future possibility. The report also shows that there are options that could be realized in the near future. For these options the needed technologies for nitrogen fertilizer based on renewable energy is commercially available. It is "only" a matter of putting together the various elements that is needed. These options are expected to be about 2-3 times more expensive than conventionally produced nitrogen fertilizers. One of the most promising alternatives is to make urea of biogas, which is estimated to cost approx. 20 SEK/kg N. Another option is to produce ammonium nitrate from wind power, which is estimated to cost approx. 24 SEK/kg N. The different technology options – different renewable energy sources – each have their pros and cons. When comparing processes based on wind powered electrolysis and reforming of biogas, production costs are similar. Biogas has however a lower investment cost and a lower proportion of fixed costs. Biogas is also a less intermittent energy source, which is a clear advantage over wind that becomes heavily dependent on a hydrogen storage system or the regional energy system to equalize variations in electricity production. Being dependent on the regional energy system means greater risk for cost variation. Reliance on the regional energy system can also be important for the climate impact assessment, depending on how electric power is generated in the region. Regarding the choice of the final nitrogen fertilizer product, we can conclude that ammonia is the cheapest to produce. However, there is no infrastructure or experience of handling anhydrous ammonia in Sweden, indicating that distribution, storage, handling and use would all require extra investment costs. There are however large risks connected to the handling of anhydrous ammonia as it is dangerous for the environment and to human health in case of leakage. In the comparison between ammonium nitrate and urea, we can see that the estimated production costs are quite similar, with a slight advantage for urea. Urea does however need a source of carbon dioxide, making it an unsuitable option in combination with wind power. Ammonium nitrate is also associated with large risks in storage and distribution, as it is highly explosive. One of the purposes of producing nitrogen fertilizer based on renewable energy is to reduce the greenhouse gas emissions that are associated with agricultural production. In this report, a summary is made of results from previous life cycle assessment studies. Emissions of greenhouse gases for the production of nitrogen fertilizer based on renewable energy was found to vary between 0.1 to 1.5 kg CO2-eq / kg N, compared with production based on fossil energy that varies between 2.2 to 14.2 kg CO2-eq / kg N. Thus, the nitrogen fertilizers based on renewable energy would yield significant climate benefits compared to conventional, fossil alternatives. Using renewable energy for fertilizer production is thus an opportunity to utilize renewable resources in a new way to mitigate climate change, while at the same time reducing the dependency of agricultural production on fossil energy market volatility. We conclude that in the short term biogas-to-urea seems like a very promising option that should be studied further. In the longer term, biomass gasification becomes more interesting, given that the technology of gasification proves itself successful in commercial applications. Although there are actors showing interest in renewable fertilizers, there is yet no market for such products. Articulating a demand pull for renewable fertilizers, as well as formulating policy instruments for a technology push are important aspects that need to be investigated further.
|
|
| 5. |
- Ahlgren, Serina
(författare)
-
Produktion av kvävegödsel baserad på förnybar energi : en översikt av teknik, miljöeffekter och ekonomi för några alternativ
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Mineralkvävegödsel är en av förutsättningarna för de höga skördenivåer som uppnåtts i det industrialiserade, moderna jordbruket. I Sverige finns idag ingen inhemsk produktion av mineralkvävegödsel, utan hela efterfrågan tillgodoses med import från utlandet. Produktionen är idag baserad på fossila resurser, vilka används både som råvara för produktionen och som energi för att driva processerna. Vi är alltså beroende av utländska fossila resurser – som bränsle och mineralgödsel – för vår livsmedelsproduktion. Möjligheter finns dock att producera kvävegödsel med på förnybara resurser, vilket banar väg för en mer hållbar produktion av livsmedel och bioenergi. Denna rapport syftar till att beskriva och jämföra olika tekniska alternativ för produktion av kvävegödsel baserad på förnybara energikällor. Rapporten presenterar produktionskostnader som beräknats utifrån tekno-ekonomiska modeller av produktionsprocesserna, miljöpåverkan av förnybara gödselmedel enligt ett flertal livscykelanalyser, samt en översikt av potentiella nyttor och risker. Rapporten kan läsas som en förstudie, vilken kan användas som informationsunderlag för aktörer och intressenter som har intresse av att stödja utvecklingen av förnybara gödselmedel. Resultaten visar att kostnaden för att producera förnybara kvävegödselmedel varierar beroende på vald teknik och tillverkningsskala. Bland de förnybara alternativen som studerades, gav förgasning av biomassa den lägsta produktionskostnaden. För detta alternativ beräknades produktionskostnaden till 11-14 kr/kg N, vilket kan jämföras med dagens pris på ca 10 kr/kg N. Förgasning av biomassa är dock ännu inte en fullt kommersiellt tillgänglig teknik, utan en framtida möjlighet. Studien visar också att det finns alternativ som kan förverkligas inom en snar framtid, där all teknik för kvävegödsel baserad på förnybar energi finns tillgänglig. Det är ”bara” att sätta ihop de olika delarna som behövs. Dessa alternativ uppskattas bli 2-3 gånger så dyra som dagens kvävegödselmedel. Ett av de mest lovande alternativen är att göra urea av biogas, vilket uppskattas kosta ungefär 20 kr/kg N. Ett annat alternativ är att producera ammoniumnitrat från vindkraft, vilket beräknas kosta runt 24 kr/kg N. De olika tekniska alternativen har sina för- och nackdelar. Vid en jämförelse mellan processer som bygger på vindkraftsbaserad elektrolys och reformering av biogas är produktionskostnaderna liknande. Biogasalternativet har dock en lägre investeringskostnad och lägre andel fasta kostnader. Biogas är också en mindre intermittent energikälla, vilket är en klar fördel jämfört med vindkraft som blir starkt beroende av ett vätgaslager eller det regionala energisystemet som utjämning för variationer i elproduktion. Att vara beroende av det regionala energisystemet innebär större kostnadsrisk och det blir även viktigt när klimatpåverkan beräknas hur övrig el produceras i systemet. Vad gäller val av slutprodukt kan vi konstatera att ammoniak är billigast att producera. Vi har dock ingen infrastruktur eller vana av att hantera vattenfri ammoniak i Sverige. Det betyder att distribution, lagring, hantering och användning skulle kräva många extra investeringar. Då koncentrerad ammoniak är miljö- och hälsofarligt är hantering av ammoniak också kopplat till stora risker vid läckage. I jämförelse mellan ammoniumnitrat och urea, uppskattas produktionskostnaderna bli relativt likvärdiga, med en liten fördel för urea. Urea kräver dock en koldioxidkälla för produktionen, vilket gör att det inte är ett lämpligt val att kombinera med vindkraftsbaserade processer. Ammoniumnitrat är också förknippat med stora risker vid lagring och distribution då det är mycket brandfarligt. Ett av syftena för att producera kvävegödsel baserad på förnybar energi är att minska utsläpp av växthusgaser från odling. Inom ramen för detta projekt gjordes en sammanställning av resultat från tidigare genomföra livscykelanalyser. Utsläpp av växthusgaser för produktion av kvävegödsel baserad på förnybar energi visade sig variera mellan 0,1 – 1,5 kg CO2-ekv/kg N, vilket kan jämföras med produktion baserad på fossil energi som varierar mellan 2,2 – 14,2 kg CO2-ekv/kg N. Alltså ger grönt kväve en avsevärd klimatnytta jämfört med fossila alternativ. Att använda förnybar energi till kvävegödselproduktion utgör alltså en möjlighet att utnyttja förnybara resurser på ett nytt, klimateffektivt sätt, samtidigt det minskar jordbruksproduktionen beroende av den fossila energimarknadens instabilitet. Vår samlade bedömning är att på kort sikt verkar biogas till urea som ett mycket lovande alternativ som bör studeras vidare. På längre sikt är förgasning av biomassa mer intressant, förutsatt att tekniken för förgasning lyckas slå igenom på kommersiell skala. Även om det finns aktörer som visar intresse för förnybara kvävegödselmedel finns ännu ingen marknad för dessa produkter. Att skapa efterfrågan hos konsumenter, samt att driva på utvecklingen hos producenter genom olika typer att styrmedel är viktiga aspekter som bör studeras vidare.
|
|
| 6. |
- Amentae, Tadesse Kenea
(författare)
-
Evaluation of supply chains and post-harvest losses of selected food commodities in Ethiopia
- 2016
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Supply chain management practices and losses in food value chains of three major food commodities in Ethiopia (milk, teff and warqe or enset) were evaluated in this thesis. Teff is a cereal, while warqe is a perennial plant from which the food products kocho and bulla are extracted. Teff, kocho and bulla are staple foods for many Ethiopians. In the three case studies, value chain analysis, questionnaire-based loss estimations and Likert scale-based loss factor evaluation were applied. Qualitative and quantitative primary data were collected using a semi-structured survey questionnaire and key informant interviews. The data were analysed using descriptive statistics, Tobit and Probit models in SPSS and Microsoft Excel software. The study identified major chain actors and losses at each stage of the food supply chains. In the milk chain, estimated losses were 3.35%, 5.46%, 2.45%, 0.95%, 1.23% and 0.88% at producers, cooperatives/union, wholesalers, retailers, processors and catering institutions, respectively. In the teff chain, estimated losses were 8.18%, 1.67%, 2.85% and 3.58% at producers, wholesalers, retailers and catering institutions/consumer stage, respectively, while the corresponding values in the kocho chain were 5.8%, 15.2%, 24% and 5.8%, respectively. In the bulla chain, 1.4%, 3.1%, 12.6%, 28.8% and 4.5% losses were estimated to occur at producers, wholesalers, retailers, processors and catering institutions/consumer stage, respectively. The loss hotspots identified were cooperatives, farmers, retailers and processors for milk, teff, kocho and bulla, respectively. Poor handling at collection points, the threshing process and poor packaging and processing facilities were among the major problems causing losses. Tobit model analysis identified distance to the nearest market as the most important factor for farmers’ post-harvest losses, while Probit analysis identified attendance in formal education as most determining for value addition decisions in the teff chain. Relationships among the chain actors were mostly based on spot transactions, lacking long-term market orientation and adequate mutuality and trust. However, application of supply chain management (SCM) practices could potentially improve the overall supply chains and reduce food losses.
|
|
| 7. |
- Amiri, Saeid
(författare)
-
On variance estimation and a goodness-of-fit test using the bootstrap method
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the study of variance estimation using the bootstrap method, including the problem of choosing between nonparametric and parametric bootstrap methods. Paper I compares the two approaches, determines which method is preferable and analyses the accuracy of the approximations. The underlying concept of parametric bootstrap is based on the assumption of correct choice of parametric distribution. Paper II therefore considers goodness-of-fit tests and presents a new test based on the bootstrap method.
|
|
| 8. |
- Anerud, Erik
(författare)
-
Stump as a fuel : the influence of harvesting technique and storage method on fuel quality of Norway spruce
- 2010
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Uncertain long-term availability of fossil fuels and the negative environmental impact of using it have created an urgent need for reliable renewable energy sources. Wood fuel, particularly forest residues is one of these sources which are in high demand in Sweden today. Stumps can be used as a complement to these, since they contain high concentrations of energy-rich lignin and extractives. However, stump removal can have negative environmental effects such as reduction of biodiversity and disturbance of nutrient balance in the soil. As to the fuel quality of stump biomass, there are some concerns connected with the utilisation of stumps since presence of excessive contaminants leads to high ash contents which reduce its value as fuel and causes operating problems. To ensure the supply of fuel of acceptable quality, an optimal system for harvesting, handling, and storage must be devised for stump procurement. The main aim of this work was to evaluate various stump harvesting techniques, storage methods (windrow or heaps), and different storage durations at two geographical locations and examine their effect on the fuel quality of Norway spruce stump biomass. Fuel quality parameters moisture content, ash content and calorific value were evaluated on five occasions during May 2008 - September 2009. Stump harvesting techniques that split the stumps allowed better drying during 13 months of storage. Storage method had no clear effect on these stumps. The ash content decreased considerably, particularly when transport and crushing took place at temperatures exceeding 0°C. In general, fuel quality was improved in all treatments after storage. However, as the storage time progressed, the net energy increment became continuously smaller due to the increased substance losses.
|
|
| 9. |
- Aradom Messmer, Samuel
(författare)
-
Animal transport and welfare with special emphasis on transport time and vibration including logistics chain and abattoir operations
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During transport animals are exposed to a number of stressors such as, separation from familiar and mixing with unfamiliar groups, vibration and transport time. Logistics chain of animals comprises collecting from farms, transport, unloading and slaughter chain operations. The current licentiate thesis deals with transport of pigs and cattle from farms to abattoirs including all logistics chain. Two trucks with natural ventilation and air suspension systems were used for field experiments. Stress hormones such as cortisol, glucose, lactate and creatine kinease, ethological parameters, carcass pH value, temperature and relative humidity were measured to study effect of transport on pigs welfare. Vibration levels on chassi, floor and cattle were studied and the influence of speeds, road types and cattle standing orientations on vibration levels were investigated. Field measurements were also conducted to describe the potential effect of operations planning and route optimization on welfare and meat quality. Highest pH24 value was (5.990.29) at 12 h summer transport time. Concentrations of cortisol was inversely proportional (P<0.001) to transport time, lactate and creatine kinase (P<0.002) positively correlated where as glucose level (P<0.01) was highest at 8 h transport time. Lying, sitting and rooting correlated with transport time (P<0.009). On cattle, highest vibration was 2.27±0.33 m s-2 during transport on gravel road at 70 km h-1. Vibrations in horizontal and lateral directions were lower on animals positioned perpendicular to driving direction. Uneven distributions of arrivals affected handling at the delivery gate. Unloading, including waiting and preparation, varied between 7 and 98, with an average of 23.7 minutes. Queues at washing occurred at 29% of deliveries, with waiting of up to 56 minutes. Potential savings for individual routes was up to 23%, consequently reducing negative impact on animal welfare, meat quality and environment. Based on climatic conditions, behaviours, stress hormones, and final carcases pH values, an increase from 4 to 8 h had higher effect than from 8 to 12 h transport time. To reduce vibration levels animal transporters more have to adapt vehicle's speed to road and animal conditions. Time and distance of transport activity can be reduced through effective planning and route optimisation which also improves animals' welfare and environmental impact.
|
|
| 10. |
- Azzi, Elias, et al.
(författare)
-
Guidelines for estimation of biochar durability : Background report
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Biochar is produced by heating biomass in the total or partial absence of oxygen. This report addresses the long-term persistence of biochar in soil and how this can be managed in climate calculations and reporting. The report consists of this summary and four chapters, which can be read independently.Different terms have been used to describe the durability of biochar carbon storage, but also the physical presence of biochar in soils, e.g. persistence, permanence, recalcitrance, residence times, stability. Today, the term “durability of carbon storage” is preferred in policy contexts, but various academic disciplines such as soil science have other established terms like “persistence”. Here, both durability and persistence are used, rather interchangeably. It is important to be aware of differences in meaning that exist between disciplines.The purpose of this report is to present the state of knowledge regarding the proportion of carbon in biochar that remains in the soil over time and provide recommendations for calculating this. There is a need to calculate the persistence of biochar in soil for national climate reporting, corporate climate reporting, carbon credit trading, and life cycle assessments for various purposes.On the persistence of biocharThe amount of biochar remaining after a certain time depends on the properties of the biochar and the environment in which it is located. Nearly all research on biochar persistence has focused on its application in agricultural soils.The main reason for the high durability of biochar carbon storage is the formation of fused aromatic stable structures during biomass pyrolysis. A high degree of fused aromatic structures makes biochar much less prone to microbial decomposition than fresh biomass.Different biochars have different properties, and this influences how long they persist in the soil. To achieve biochar with properties that provide higher persistence, it should be produced at higher temperatures for a sufficient duration.Measuring and calculating biochar persistenceEstablished quantification methods of 100-year biochar persistence (e.g. referenced in IPCC inventory guidelines and used in voluntary carbon markets, to date) extrapolate short-term soil decomposition processes, and do not fully consider the processes that may explain millennial persistence.Calculations regarding biochar persistence have traditionally used a time span of 100 years to describe the amount of remaining carbon after a certain time. The use of specifically 100 years lacks a well founded scientific reason, but has been regarded as “far enough” into the future from a climate perspective and close enough for modelling to be meaningful.An active area of research relevant for the understanding biochar carbon storage durability is the development of advanced analytical characterisation methods of biochar that will enable measurement of the physicochemical heterogeneity in carbon structures present in biochar.Another area of continued research is biochar incubation, with a focus on field conditions, to elucidate both differences from laboratory conditions, and how transport processes affect biochar in the field.Recommendation and conclusionIn the project, available research data has been aggregated into a functional model that calculates how much of the carbon in biochar remains after a given number of years. The model is based on the H/C ratio of the biochar placed in the soil and the annual average temperature at the location.The model is made freely accessible to provide biochar market actors with the best available knowledge for estimating the durability of biochar carbon.Existing research results provide a sufficient foundation for estimation of the amount of biochar expected to remain over time. Future research results are expected to lead to increased knowledge regarding the decomposition properties of biochar, in particular biochars with a very low H/C ratio. Therefore, this recommendation will be revised by the end of the project in 2025.
|
|
| 11. |
- Bernesson, Sven, et al.
(författare)
-
Glycerin från omförestring av vegetabiliska oljor som tillsatsmedel : praktiska försök med pelletering och eldning av några biobränslen
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During transesterification of vegetable oils in particular, but also animal fats and used frying oils, glycerine is obtained as a by-product. It is important for transesterification economics that the glycerine by-product can be sold for the best possible price. In Sweden today, glycerine is often sold to biogas production for a few Swedish crowns per kilo. If other markets where glycerine replaces a more expensive product can be found, the willingness to pay for glycerine will increase. This project examined whether glycerine can be used as an additive in pelleting some biofuel types, and the value it would have in this use. The project investigated admixtures of appropriate amounts of glycerine of varying quality during pelleting of some types of fuel (straw, reed canary grass and pine wood). To determine how these affect pellet quality, the function of the pellet press, pellet storage properties, the risk of harmful emission levels of carbon monoxide (CO), nitrogen oxides (NOx), sulphur oxides (SO2) and aldehydes during incineration of the pellets, the risk of ash sintering and the risk of corrosive deposits in flue gas channels were examined. In addition, the commercial value of the glycerine when added to pellets was estimated. Pelleting trials were conducted using 1% and 5% admixtures of four types of glycerine in three types of fuel. Two of the glycerine products were alkaline, originating from alkaline transesterification of rapeseed oil, and two were acidic, originating from acid esterification/transesterification followed by alkaline transesterification, of rapeseed oil in one case and used frying oil in the other. The fuel types were pine wood, reed canary grass and straw. After pelleting, pellet durability, the amount of fine fraction and bulk density were measured. Chemical analyses were performed of glycerine types, fuel types and glycerine/fuel mixtures to evaluate ash melting behaviour and the risk of corrosion associated with alkali chlorides. Pellets from the trials were stored for 6 months, during which time moisture uptake and the incidence of mould were studied. After the storage experiments, pellet durability was measured again. Wherever possible, the experimental design was evaluated statistically using multivariate data analysis. About half the samples were incinerated and emissions of CO, NOx, SO2, particulate matter, acrolein and formaldehyde were measured. In addition, the average temperature and maximum temperature during incineration were measured and the amount of combustion residues and their content of unburned and sintered material were determined. Some ash samples from the combustion of glycerine/pine wood mixes were sent for chemical analysis. The admixture of glycerine in the fuel types generally resulted in pellets with lower durability, higher proportion of fines (fine fraction) and significantly lower bulk density. However, pellets with the same or slightly better durability and the same or lower proportion of fines were obtained by admixture of 1% acidic glycerine to the fuel types. The specific energy consumption for pelleting the fuels containing glycerine was generally lowered, which may have been due to the lubricating properties of the glycerine. The addition of glycerine in all cases resulted in a decrease in pellet bulk density. Reed canary grass had the best durability, least share of fines and highest bulk density, while straw usually had the worst durability, highest share of fines and lowest bulk density. During the storage experiments the pellets took up some water, but never to such a level that the storability was compromised. Pellets with glycerine took up more water, often an increasing amount with increasing glycerine content. Mould was not found in any pellets from any experiment. Durability deteriorated more frequently with higher glycerine content, and thus low durability in the pellets at the outset. The initial moisture content and thus the type of fuel were also of great importance for moisture absorption. Straw contained most moisture from the start and took up the most water. In addition, durability decreased most for straw during storage. During incineration, the main problem with an increasing admixture of glycerine in the fuels was an increasing amount of particles in the flue gas. Calculations of potassium (K) losses with the flue gases, based on analysis of fuels and their ash composition, suggested that this increased sharply with increasing admixture of glycerine. For example, incineration of pine wood with about 1% added glycerine increased the amount of K leaving with the flue gases to the level observed with straw incineration. There seemed to be a close link between the amount of particles in the flue gas and the amount of K released. It is therefore likely that addition of glycerine will cause problems with corrosive deposits in the flues for fuels that normally do not present such problems. However, with fuels that normally give rise to such problems, e.g. straw, it is likely that there will be little obvious difference. Glycerine (acid) containing sulphur can probably prevent particle release and thus lower the risk of corrosion associated with alkali chlorides in the flue gas. The emissions of acrolein and formaldehyde did not increase as might be expected in experiments with glycerine admixture. The levels of acrolein were below the detection limit, and the levels of formaldehyde were very low. Emissions of CO, NOx and SO2 varied widely between experiments in a more or less random way. However, CO emissions may have increased with lower pellet quality. Sulphur dioxide should be produced during incineration of pellets with high sulphur levels. Ash melting point declined in pine wood in particular on addition of glycerine, but also in reed canary grass. The ash melting point for straw was not affected at all by glycerine admixture. The reason why pine wood ash was more sensitive is that the amounts produced from pine are so small that properties of the glycerine ash can have an impact even at small admixture rates. The K content of reed canary grass is so low that very little glycerine with high K content is required before its properties start to become apparent. However, straw has a high initial content of an ash that is already high in K, so the K content of glycerine ash is les obvious even at rather high admixture rates. Calculations using key numbers showed that the ash melting point of reed canary grass in particular should be lowered by the admixture of glycerine, but also that of pine wood to a lesser degree, from an initially high level. Straw ash should scarcely be affected at all. High losses of K in the flue gases can suppress the problem of ash melting point depression in bottom ash. Some of the glycerine types initially had high contents of methanol. It is important that this can be removed, as it constitutes a fire hazard during pelleting and also during transport and handling of the glycerine. High methanol concentrations are also a human health risk, as methanol is toxic. The commercial value of the glycerine is at one of three different levels depending on how it functions when mixed in different fuels. A) If glycerine admixture degrades a good fuel such as wood in terms of the risk of acid deposits in the flue so much that it is similar to straw as a fuel, glycerine value has a negative value. B) On admixture of glycerine in a poor fuel, such as straw, the properties of the glycerine are not evident and its value based on the energy is therefore the same as for the pure fuel. This is currently approximately SEK 0.6-0.9/kg glycerine, which can be compared with the current price of SEK 1/kg for glycerine in biodigestion applications. These factors combined make it difficult to find a profitable use for glycerine as an additive in pelleting or when used as fuel. Glycerine would therefore not be of commercial interest for use in these applications. C) If the glycerine acts as an additive in very small amounts at pelleting, most likely as a lubricant, the value would then be about SEK 3/kg. However, only small amounts would be used in this application, probably just a few hundred tonnes per annum. The advice to the industry is that glycerine should not be used in pelleting as it probably does not work well for this application. If glycerine is incinerated, it should be co-fired with a poor fuel, so as not to impair the properties of the fuel. Glycerine is probably more profitable in applications other than fuel to produce heat. At low addition rates glycerine could probably act as a lubricant during pelleting of certain fuels. However, more research is required to determine whether glycerine can act as a lubricant along with some cheap binding agent in pelleting of fuels
|
|
| 12. |
- Bernesson, Sven, et al.
(författare)
-
Svensk spannmålsbaserad drank : Alternativa sätt att tillvarata dess ekonomiska, energi- och miljömässiga potential
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Spannmålsdrank används huvudsakligen till utfodring. Den kan utfodras antingen i blöt form (8,5-28 % ts), eller i torr form (90 % ts). Vanligen utfodras nötkreatur och grisar med drank, men även andra djurslag inom jordbruket kan utfodras. Dranken kan även användas som biogasråvara, bränsle eller som organiskt gödselmedel. Efter jäsningen återstår spannmålens smältbara protein i dranken (primärdrank) i huvudsakligen oförändrad form, medan nästan all stärkelse gått bort. Dranken blir därför ett proteinfoder. Då även fiberpolysackarider (cellulosa och hemicellulosa) återstår i denna drank, och dessa med annan processteknik kan brytas ner till jäsbara sockerarter och jäsas till etanol, och den drank som då återstår, s.k. sekundärdrank, kan användas i liknande tillämpningar som normal (primär) drank, studeras även detta i det här projektet. En nackdel med denna teknik är att en del av aminosyrorna i drankens protein bryts ner. I de ekonomiska beräkningarna och livscykelanalyserna har det antagits att 50 % av lysinet och 20 % av metioninet brutits ner i denna sekundära drank. Arbetets syfte var att utvärdera hur spannmålsdrank kan användas i olika applikationer, samt att beräkna dess ekonomiska värde och produktionskostnader vid dessa användningar. Vidare att ta fram miljöbelastning såsom bl.a. emissioner av växthusgaser och energibehov för de olika användningarna vid produktion av etanol och drank. Dessutom att analysera betydelsen av att dranken behandlas med ytterligare en process, där en del av spannmålens cellulosa och hemicellulosa omvandlas till etanol, och sekundärdrank erhålles. Idisslare, som nötkreatur och får, kan utfodras med en stor del av proteinet i fodret som vetedrank. Protein från andra källor kan behövas för att den totala mängden protein ska bete sig på önskat sätt vid matsmältningen. Till grisar och fjäderfä kan drygt 10 %, respektive ca 10 %, av fodret bestå av vetedrank. Smågrisar är känsliga för fodrets smaklighet, och det är därför inte säkert att de alltid kan äta foder som innehåller vetedrank. Till fjäderfä kan man få begränsa inblandningen av drankprodukter i fodret om gödseln skulle bli blöt och kladdig. Till hästar kan ca 10 %, i bästa fall uppåt 20 %, av kraftfodret bestå av vetedrank om man ej drabbas av smaklighetsproblem. Spannmålsdrank kan eldas antingen blöt eller torkad beroende på eldningsutrustningen. Drank med ursprung i spannmål innehåller höga halter alkalimetaller, som ger en aska med låg smältpunkt, vilket gör att den troligen sintrar lätt. Höga halter av svavel och klor kan ge problem med korrosion. Mängden aska är ganska stor, ca 5 % av torrsubstansen. Det höga innehållet av kväve (ca 5 % av ts) gör att kväveoxidemissionerna sannolikt blir höga, och då i nivå med vad som erhållits vid eldning av rapsexpeller med ungefär samma kvävehalt, 2-3,6 gånger jämfört med kvävefattiga bränslen. Utnyttjas även en del av cellulosan och hemicellulosan för produktion av etanol (i en sekundär process), koncentreras de ämnen som ger problem vid eldningen, vilket ökar sannolikheten för problem. Dessutom blir askhalten högre, medan det totala värmevärdet minskar i takt med att cellulosa och hemicellulosa blir till etanol. Som gödselmedel innehåller drankens torrsubstans ca 5,7 % kväve, 0,8-1,5 % fosfor och 0,9- 1,9 % kalium. Beräkningar ger att sekundärdranks torrsubstans bör innehålla ca 7,4 % kväve, 1,0-2,0 % fosfor och 1,2-2,4 % kalium. Det organiskt bundna kvävet mineraliseras (frigörs) troligen långsamt såsom hos t.ex. rapsexpeller. Drank går bra att röta till biogas. Växtnäringen i rötad drank blir sannolikt mer växttillgänglig efter rötningen. Drank är ett kväverikt substrat som kan ge problem med hög halt av ammoniumkväve i biogasreaktorn. Detta gäller i högre utsträckning för sekundärdrank där näringsämnena koncentrerats då en del av cellulosan och hemicellulosan blivit till etanol. Utbytet i processen borde kunna bli 60-70 %, vid goda förhållanden kanske 80 %. Kostnadsberäkningar har gjorts där det ekonomiska värdet hos spannmålsdrank beräknats utifrån de ekonomiska värdena hos korn och sojamjöl (omsättbar energi och råprotein till nötkreatur och hästar eller lysin till grisar och fjäderfä eller metionin till fjäderfä) vid utfodring, skogsflis vid eldning (effektiva värmevärdet), kväve, fosfor och kalium vid användning som gödselmedel, samt försäljning av el och fjärrvärme från en större gårdsanläggning för biogas inklusive värdet av kväve, fosfor och kalium i rötresten vid rötning. Vid rötningen studerades fall med både 60 och 80 %:s utbyte, samt fall exklusive och inklusive rötningskostnaderna. Kostnaderna studerades för åren 2005-2010. Primärdrank fick högst värde vid användning som foder till fjäderfä (metionin) följt av: foder till hästar och nötkreatur, biogas (80 %) exkl. rötningskostnader, biogas (60 %) exkl. rötningskostnader, foder till fjäderfä (lysin) och grisar, gödselmedel, eldning för uppvärmning, biogas (80 %) inkl. rötningskostnader och sämst biogas (60 %) inkl. rötningskostnader. För sekundärdrank ändras ordningsföljden så foder till hästar och nötkreatur får högst värde följt av: foder till fjäderfä (metionin), biogas (80 %) exkl. rötningskostnader, biogas (60 %) exkl. rötningskostnader, gödselmedel, foder till fjäderfä (lysin) och grisar, biogas (80 %) inkl. rötningskostnader, eldning för uppvärmning och sämst biogas (60 %) inkl. rötningskostnader. Värdet för sekundärdrank är högre än för primärdrank vid alla användningar utom vid utfodring av grisar och fjäderfän (baserat på lysin eller metionin). Orsaken till det lägre värdet, som foder till grisar och fjäderfän, är att i sekundärprocessen för att utvinna 13 % mer etanol, bryts 50 % av lysinet och 20 % av metioninet ner. Världsmarknadspriserna på korn och sojamjöl har en stor inverkan på drankens värde, liksom utbyte m.m. från biogasanläggningen. Priserna på skogsflis och gödselmedel hade något mindre inverkan på resultatet då dessa produkter hade ett lägre värde från början. Livscykelanalyser har gjorts av produktionen av etanol med systemutvidgning, där dranken ersätter andra produkter beroende på dess användning. Följande produkter ersätts beroende av drankens användning: sojamjöl och korn vid utfodring (råprotein till nötkreatur och hästar; lysin till grisar och fjäderfä; metionin till fjäderfä); skogsflis vid eldning; konstgödsel NPK vid gödsling; vall till biogas och överskottskonstgödsel vid biogasråvara. För primärdrank blir, för global uppvärmning, ordningsföljden från lägst påverkan: fjäderfä (metionin), hästar och nötkreatur, fjäderfä och grisar (lysin), biogas (80 % och 60 %), gödselmedel och sämst eldning. Ordningsföljderna blir ungefär desamma för försurning och eutrofiering. För energiåtgång blir ordningsföljden från lägsta: biogas (80 % och 60 %), gödselmedel, eldning, fjäderfä (metionin), hästar och nötkreatur och sist fjäderfä (lysin) och grisar. För sekundärdrank blir, för global uppvärmning, ordningsföljden från lägst påverkan: hästar och nötkreatur, fjäderfä (metionin), biogas (80% och 60 %), grisar och fjäderfä (lysin), gödselmedel och sist eldning. För energiåtgång blir ordningsföljden från lägsta: biogas (80% och 60 %), hästar och nötkreatur, fjäderfä (metionin), gödselmedel, eldning, och sist grisar och fjäderfä (lysin). Produktionen av etanol och sekundärdrank ger lägst miljöbelastning då sekundärdranken blir foder till nötkreatur och hästar, samt används som biogasråvara. Vid de andra användningsområdena för dranken, ger produktionen av etanol och primärdrank lägst miljöbelastning. Energiåtgången för produktion av etanol och sekundärdrank blir, för samtliga användningsområden för dranken, högre än vid produktion av etanol och primärdrank. Orsaken till detta är att en energikrävande extra process tillkommer vid produktionen av etanol och sekundärdrank. Låter man istället biogasen, i det ovan beskrivna systemet, ersätta bensin direkt i lätta fordon, blir miljövinsten vad gäller växthusgaser större än i alla andra fall beroende på att ett fossilt bränsle ersätts direkt. Till skillnad från de andra studerade användningsområdena för dranken, blir primärdrank bättre än sekundärdrank då den har mer cellulosa och hemicellulosa kvar som kan bli till biogas. Även energivinsten visar upp ett liknande resultat som växthusgaserna. Energibalanser, som kan beskrivas som kvoten mellan utgående energi hos etanol och drank som effektivt värmevärde, och energiåtgången i alla steg för hela produktionskedjan, beräknades. Dessa innehåller alla steg från odlingen av höstvetet tills dess att det färdiga etanolbränslet är färdigt att tanka och dranken är transporterad till gården och då är färdig att utfodra. Dess värden har beräknats till 1,96 för etanol och primärdrank från en ordinär etanolprocess och 1,75 för etanol och sekundärdrank från en process som ger 13 % mer etanol från även en del av spannmålens cellulosa och hemicellulosa. Om dranken inte torkas förbättras dessa energibalanser till 2,84 respektive 2,22. Om halva arealen av vete, korn och rågvete (knappt 400 000 ha) används till etanol skulle knappt 600 000 ton primärdrank erhållas. Nuvarande djurbestånd kan konsumera ungefär två tredjedelar av denna, varav mjölkkorna en tredjedel och slaktsvinen knappt en sjättedel. Om även en del av spannmålens cellulosa och hemicellulosa används för etanolproduktion erhålls ca 470 000 ton sekundärdrank, av vilken nuvarande djurbestånd kan konsumera ca tre fjärdedelar, varav mjölkkorna knappt två femtedelar och slaktsvinen knappt en femtedel.
|
|
| 13. |
- Bos, Marlies
(författare)
-
Greenhouse gas emissions when freezing and thawing sewage sludge and compost
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Freezing/thawing cycles can significantly increase greenhouse gas emissions due to physical and biological mechanisms. Therefore this research was done to see if this is also the case for compost and sewage sludge. The main focus was on nitrous oxide. The set-up of the experiments was based on the outcomes of several trial experiments. 4 substrates were tested: non-nitrified mesophilic sewage sludge, nitrified mesophilic sewage sludge, 2 weeks old compost and 1 month old compost. The two composts had a clear difference in ammonium content. The substrates were first frozen at a temperature of -27 °C, and then thawed at a temperature of 5 °C. Controls were kept at a temperature of 5 °C during the whole experiment. All substrates were tested in triplicates. Emissions of carbon dioxide, methane and nitrous oxide were measured. No clear effect of freezing/thawing was observed on the greenhouse gas emissions from non-nitrified sewage sludge. From the nitrified sewage sludge the emissions of both carbon dioxide and nitrous oxide increased during thawing. The cumulative emission of carbon dioxide was 17500 µg g-1 initial C from the frozen and thawed sewage sludge, and 11170 µg g-1 initial C from the controls. The cumulative emission of nitrous oxide in the sewage sludge that had been frozen and thawed was about 3500 µg g-1 initial N, for the controls this was 3000 µg g-1 initial N. Both the increase carbon dioxide and nitrous oxide emissions were probably due to increased substrate availability, caused by the die-off of micro-organisms during freezing. The nitrous oxide probably came from denitrification. In both of the composts no effect of the freezing and thawing was observed on the emissions of carbon dioxide and methane, but it had a clear effect on the emission of nitrous oxide: in the 1 month old compost a clear emission peak was observed during the first days of thawing. For the one month compost this was probably due to a physical mechanism of trapped nitrous oxide inside the compost which could escape during the thawing period. An unexpected result was the large difference between the two composts considering the amounts of nitrous oxide emissions, which were expected to be approximately the same due to equal nitrate amounts. However, the cumulative nitrous oxide emission from the frozen and thawed 2 weeks compost was 3,00 µg g-1 initial N at the end, while from the 1 month compost this was 1220 µg g-1 initial N. Since the ammonium in the 1 month compost had decreased with 32,5%, and only 17,5% for 2 weeks compost, the large amount of nitrous oxide probably came from the conversion of ammonium. However, it is still not clear whether this comes from nitrification of the ammonium, or from denitrification of the nitrate formed during the experiment. The conclusion was that freezing/thawing increases emissions of carbon dioxide and nitrous oxide from nitrified sewage sludge during thawing, and the emissions of nitrous oxide from compost during thawing. Recommendations for further research are to find out which processes, nitrification or denitrification, are responsible for the nitrous oxide production. Also research to compost with different nitrate amounts is recommended.
|
|
| 14. |
- Bulitta, Sorri Fufa
(författare)
-
Effects of handling on animals welfare during transport
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transportation is a very complex event which compromises animal welfare and meat quality. Even though important research works have been reported related to animal transport and welfare, many questions are still remaining to be addressed, particularly on the effect of transport time, vibration and climatic conditions. The main objective of this thesis was to investigate the effects of handling and transport on animals' welfare. The main methodologies employed comprehensive field measurement to collect data, observations, video filming for behavioural study and modeling. The thesis is structured into 3 papers. Paper I focuses on the modelling the dynamic performance of heart rate during loading for transport. Paper II and III are dealing with vibration and effect of transport on welfare of cattle and pigs' respectively. The model developed to describe the heart rate performances fits and successfully simulates the heart rate. The heart rate increased rapidly from resting value to peak value and then remains under stress, partially under stress or fully (100%) recovered. The speed, road conditions and standing orientations of animals had effect on level of vibrations. In all road types and speeds, standing orientation of animals facing in driving direction generally exposed to higher horizontal and lateral vibrations than animal facing perpendicular to the driving direction. The three common resonance frequencies identified were 1.3, 5.1, and 12.6 Hz in the second peak at 23Hz in vertical direction on tarmac road at the speed of 85km/h. Cortisol concentration level elevated during short transport time and decreased with an increase of transport time. Highest and lowest glucose concentrations for winter and summer were at 8 h and 12 h transport time respectively. Concentrations of lactate and creatine kinase positively correlated with transport time. The pH24 values correlated with transport time during summer. Behaviours such as lying, sitting, rooting, smelling, panting, fighting, restlessness, change of position and vocalization correlated with transport time. The overall conclusion from the study was that transport and handling had significant effects on animal welfare. The model developed described well the dynamic response of heart rate of the animals during loading for transport.
|
|
| 15. |
- Buntaran, Harimurti
(författare)
-
Assessment of statistical analysis of Swedish cultivar testing : a cross-validation study for model selection
- 2019
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Swedish official cultivar testing conducts multienvironmental trials (MET) to makerecommendations of cultivars that are well adapted to farmers’ regional conditions. Inthe MET, a large number of cultivars are tested in several geographical regions. Thetested cultivars perform differently in varying soil types and climates, a phenomenonknown as genotype×environment interactions. The MET data structure is often large andhighly imbalanced, which causes computational problems when applying some statisticalmethods. Several issues, such as prediction of crop variety performance and efficientcomputation of measure of cultivar stability are urgent to be tackled by developingcomprehensive and robust statistical methods. This study aims to address these issuesand provide a gold standard for MET analysis in Swedish official cultivar testing. In this study, we investigated several linear mixed models by using cross-validation(CV). We proposed to use random cultivar effects, known as best linear unbiasedprediction (BLUP) method to replace the current fixed cultivar effects, known as bestlinear unbiased estimation (BLUE). In theory, BLUP provides more accurate rankingsand predictions than BLUE. The current-practice analysis strategy, i.e., two-stageunweighted strategy, was also compared to several strategies such as single-stagestrategy and two-stage weighted strategies that comprise some weighting methods. In theCV, mean squared error of differences (MSEP) was used to assess the performance ofestimation of cultivar effects by BLUP and BLUE to select a model that provides bestprediction accuracy. A new inter-zone stability measure was also proposed to tacklecomputational burden and provide additional useful information regarding cultivarstability across zones and years. The MSEP revealed that BLUP outperformed the current-practice method, BLUE,and so improved the accuracy of zone-based prediction. Also, the single-stage and twostage weighted strategies outperformed the current strategy. The proposed stabilitymeasure offered a less computational resource, and provided more flexible stabilitymeasure for practical purpose.
|
|
| 16. |
- Cardoso, Marcelo, et al.
(författare)
-
Manual till JTI/SLU:s kalkylprogram för maskinkostnader i Excel : version 1
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The JTI/SLU’s Farm Machinery Cost Estimator is a user-friendly computer program developed in Excel 2000 for Personal Computers in Swedish language. The program is able to estimate the cost for a single machine or/and total machinery costs (specific machinery + labour + timeliness costs) for a set. The program is composed of seven sheets of which two are hidden: o Start sheet: with general information on the programme. o Condition sheet: with basic data on the farm and other general parameters for the calculation. o Calculation sheet for estimating costs for one machine at a time. o Summary sheet where the results from the calculation sheet can be saved. o Timeliness sheet for timeliness cost estimation for the sowing and harvesting operations. o Machinery data sheet (hidden sheet): a database with basic information for the calculation on individual machines and machinery type. o A hidden sheet (PInfo) for temporary data saving during the programme running. The Estimator has nine different pop-up windows for helping estimating field machinery capacity and fuel consumption more accuracy according to the farm conditions. In addition, there is an optimisation module for estimating optimal width for some implement types and grain harvesters. In all visible sheets, there are information buttons and Comments on the most important data to be entered and the calculation methods used. The Estimator has been tested by researchers and farmers. In a series of tests, where labour and machinery costs were estimated for more than 30 farms, it showed to be easy to use and sound cost estimations were obtained. The program (Swedish language) is available free at this Internet address: http://www2.et.slu.se/maskinkalkyl/
|
|
| 17. |
- Cengiz, Cigdem
(författare)
-
A New Approach in Profile Analysis with High-Dimensional Data Using Scores
- 2020
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In profile analysis, there exist three tests: test of parallelism, test of levels and test of flatness. In this thesis, these tests have been studied. Firstly, a classical setting, where the sample size is greater than the dimension of the parameter space, is considered. The hypotheses have been established and likelihood ratio tests have been derived. The distributions of these test statistics have been given. In the latter stage, all tests have been derived in a high-dimensional setting, where the number of parameters exceeds the number of sample size. Such settings have become more common due to the advances in computer technologies in the last decades. In high-dimensional data analysis, several issues arise with the dimensionality and different techniques have been developed to deal with these issues. We propose a dimension reduction method using scores that was first proposed by Läuter et al. (1996). To be able to find the specific distributions of the test statistics of profile analysis in this context, the properties of spherical distributions are utilized.
|
|
| 18. |
- Ciuk Karlsson, Susanna
(författare)
-
Simulating water and pollutant transport in bark, charcoal and sand filters for greywater treatment
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A septic tank combined with a sand filter is the most common onsite wastewater treatment system worldwide, since it is a simple, lowcost and reliable treatment method. Alternatives to sand in filters could be advantageous in terms of availability of material and enhanced treatment properties. In this study, flow dynamics and pollutant transport in three filter materials; sand, pine bark and activated charcoal, intermittently dosed with artificial greywater, were simulated using the HYDRUS wetland module. The simulated results were compared with observations from laboratory filters and model hydraulic and microbial parameters were calibrated. Emphasis was placed on simulating the removal of organic pollutants by each filter type. Furthermore, for the bark and charcoal filters, removal of organic matter was simulated for different hydraulic and organic loading rates (HLR = 32 and 64 l m⁻² day⁻¹ and OLR = 13-6 and 28 g BOD₅ m⁻² day⁻¹). Comparing simulated with measured cumulated effluent volume, the normalised root mean square error for all three filter materials was small (0.7-3.5%). The simulated bark filter COD removal in different loading regimes (HLR = 32 and 64 l m⁻² day⁻¹, OLR = 13-16 and 28 g BOD₅ m⁻² day⁻¹) was overestimated by 13-20 percentage points compared with the measured values. When release of organic matter from the bark material itself was accounted for, the difference was reduced to 2-10 percentage points. Simulation of the charcoal filter demonstrated 94 and 91 % removal of COD for HLR = 32 and OLR = 13 - 16 g BOD₅ m⁻² day⁻¹, which compared well with the measured values, 95 ± 2 % and 89 ± 11 %, respectively. However, simulated COD removal for Run 2 (70%) and Run 5 (72%) was low compared with the measured values (90 ± 7 and 84 ± 4 %). The measured sand filter effluent concentration of COD was 245 mg l⁻¹ and the simulated effluent concentration of COD was 134 mg l⁻¹ for HLR = 32 and OLR = 14 g BOD₅ m⁻² day⁻¹. After including an effect of water flow along the column wall in the model, the simulated effluent concentration of COD was 337 mg l⁻¹. These simulations of bark, charcoal and sand filters improved understanding of filter functions and identified possible filter design developments.
|
|
| 19. |
|
|
| 20. |
- Dalahmeh, Sahar
(författare)
-
Reclaimed wastewater use alternatives and quality standards : from global to country perspective: Spain versus Abu Dhabi Emirate
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Reclaimed wastewater use is crucial for increasing water availability, improving water resources management, minimising environmental pollution and permitting sustainable nutrient recycling. However, wastewater also contains microbiological and chemical pollutants posing risks to human health and the environment, and these risks have to be handled. Successful use of reclaimed wastewater requires stringent standards for its treatment, disposal and distribution. This report summarises global and country-specific wastewater quality standards for different reclaimed wastewater use schemes, discusses specific standards and describes reclaimed wastewater use applications in two selected countries, Spain and Abu Dhabi Emirate. The World Health Organization (WHO) Guidelines for the Safe Use of Wastewater for Agriculture focus on the protection of public health. The European Commission does not directly regulate wastewater use, but discharge of treated wastewater into water bodies is regulated by Council Directive 91/271/EEC, which requires treated wastewater to have a maximum of 25 mg BOD5/L, 125 mg COD/L and 35-60 mg total solids (TS)/L. In sensitive areas, sewage treatment plant effluent must comply with a maximum of 2 mg total phosphorus/L and 15 mg total nitrogen/L. EU Council Directive 2008/105/EC also sets environmental quality standards for priority substances, i.e. pesticides, polycyclic aromatic hydrocarbons, phenolic compounds and volatile organic compounds. In Spain, the EU directives and Royal Decree 1620/2007 regulate use of reclaimed wastewater. The Royal Decree sets quality criteria for microbial parameters, solids and turbidity for different applications. The Regulation and Standards Bureau (RSB) of Abu Dhabi Emirate sets the quality criteria for water discharging to marine and land environments and used for irrigation. These include limits for organic matter, solids, nutrient, pathogen indicators and helminths. In Spain, agriculture is the largest sector for reclaimed wastewater use, consuming approx. 350 Mm3/year. Landscape irrigation and maintenance of natural hydrological regimes are the second largest users, consuming approx. 50-60 Mm3/year of wastewater each. In contrast, only <0.5% of the water used in industry is reclaimed wastewater. In Abu Dhabi Emirate, reclaimed wastewater is not used in crop cultivation, but most of the wastewater produced is used for irrigation of public parks and roadsides (287 Mm3/year) and in forestry (130 Mm3/year). District cooling in residential areas is another application for wastewater use in Abu Dhabi Emirate. The technologies used to facilitate wastewater treatment vary. The Barcelona metropolitan wastewater treatment plant (Spain), which supplies reclaimed wastewater for use, conducts biological treatment with activated sludge, tertiary treatment with coagulation-flocculation, filtration, UV disinfection, post-disinfection and oxygen saturation. The effluent wastewater complies with the Royal Decree and EU directives. In contrast, five treatment plants in the Navarra region of Spain use secondary treatment with trickling filters or activated sludge, two having lagoons for tertiary treatment. The hygiene quality of effluent from these plants does not comply with the Royal Decree and several fail to remove persistent organic compounds and pharmaceutical residues effectively. In Abu Dhabi Emirate, the largest sewage treatment plant, Mafraq, carries out conventional activated sludge treatment, followed by sand filtration and chlorination. Its effluent complies with RSB standards, but occurrence of pharmaceutical residues in effluent wastewater has been documented in Abu Dhabi. Besides standards and regulations and appropriate treatment, other aspects which need consideration in planning reclaimed wastewater use for various applications include: cultural and socio-economic aspects, willingness of users to accept and pay for treated wastewater, online and real-time water quality monitoring, and reduced energy use and waste generation.
|
|
| 21. |
|
|
| 22. |
- De Toro, Alfredo, et al.
(författare)
-
Manual till JTI/SLU:s kalkylator för maskinkostnader i lantbruket : version 1
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The JTI/SLU’s Farm Machinery Cost Calculator is a user-friendly computer application for Personal Computer in Swedish language for estimating field machinery costs. The program is able to estimate specific machinery, labour and timeliness costs for a single machine and set. The program is composed of four sheets and two databank files: o Condition sheet where basic data on the farm and other general parameters for the calculation are entered. o Calculation sheet for estimating costs for one machine at a time. o Summary sheet where the results from the calculation sheet can be saved. o Timeliness sheet for timeliness cost estimation for the sowing and harvesting operations. o Two Microsoft Access files, one with basic background data for the calculation and the other with saving place for the user’s own calculation results. The Calculator has nine different pop-up windows for helping estimating field machinery capacity and fuel consumption with more accuracy according to user’s specific farm conditions. In addition, there is an optimisation module for estimating optimal width for some implement types and grain harvesters. In all the sheets, there are information buttons on the most important data to be entered, programme deployment and calculation methods used. The Calculator (Swedish language) is available free of charge at this Internet address: http://www2.et.slu.se/maskinkalkyl/
|
|
| 23. |
- Demissie, Natnael
(författare)
-
UV-based advanced oxidation process for nutrient stabilisation and organic micropollutant degradation in source-separated human urine
- 2023
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urine dehydration is one of the technological approach to recover nutrients in concentrated form from source separated urine. When drying fresh urine, nitrogen loss occurs due to hydrolysis of urea into ammonia unless methods to inactivate urease enzyme are employed. In addition, concerns arise when using urine-derived fertiliser due to the potential presence of organic micropollutants (pharmaceuticals). This thesis evaluated ultraviolet (UV) treatment as an alternative chemical-free nutrient stabilisation (urease inactivation) and organic micropollutant (OMP) degradation technology. Urease inactivation and OMP degradation in water and in urine (synthetic urine, real urine from human subjects) were studied in a photoreactor equipped with a low-pressure mercury UV lamp emitting light predominantly at 185 and 254 nm. Exposure of real urine to 80 min of UV irradiation resulted in more than 90% degradation of 18 out of 75 OMPs and 1-90% degradation of the remaining OMPs. Enzymatic activity fell below the detection limit for real urine exposed to 71 min of UV irradiation. However, electrical energy demand for reducing enzymatic activity below the detection limit in real fresh urine was 52-fold higher than for inactivation in synthetic fresh urine (without urea), while electrical energy demand was more than 10-fold higher for 90% OMP degradation in real fresh urine than in water. The inactivation and OMP degradation observed were probably due to direct photolysis and photo-oxidation. Presence of organic substances in real urine was the likely reason for less efficient inactivation of urease and OMP degradation, as such substances can competitively absorb incoming UV light and scavenge the free radicals formed during UV treatment. Although 20% urea was lost after UV treatment, there was no decrease in total nitrogen. In summary, UV treatment can stabilise urea-N and degrade OMPs in fresh urine and has potential for integration into urine diversion sanitation systems.
|
|
| 24. |
|
|
| 25. |
- Eneroth, Hanna, et al.
(författare)
-
Environmental impact of coffee, tea and cocoa – data collection for a consumer guide for plant-based foods
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In 2020, WWF launched a consumer guide on plant-based products targeting Swedish consumers. The development of the guide is described in a journal paper (Karlsson Potter & Röös, 2021) and the environmental impact of different plant based foods was published in a report (Karlsson Potter, Lundmark, & Röös, 2020). This report was prepared for WWF Sweden to provide scientific background information for complementing the consumer guide with information on coffee, tea and cocoa. This report includes quantitative estimations for several environmental categories (climate, land use, biodiversity and water use) of coffee (per L), tea (per L) and cocoa powder (per kg), building on the previously established methodology for the consumer guide. In addition, scenarios of consumption of coffee, tea and cocoa drink with milk/plant-based drinks and waste at household level, are presented. Tea, coffee and cacao beans have a lot in common. They are tropical perennial crops traditionally grown in the shade among other species, i.e. in agroforestry systems. Today, the production in intensive monocultures has negative impact on biodiversity. Re-introducing agroforestry practices may be part of the solution to improve biodiversity in these landscapes. Climate change will likely, due to changes in temperature, extreme weather events and increases in pests and disease, alter the areas where these crops can be grown in the future. A relatively high ratio of the global land used for coffee, tea and cocoa is certified according to sustainability standards, compared to other crops. Although research on the implications of voluntary standards on different outcomes is inconclusive, the literature supports that certifications have a role in incentivizing more sustainable farming. Coffee, tea and cocoa all contain caffeine and have a high content of bioactive compounds such as antioxidants, and they have all been associated with positive health outcomes. While there is a strong coffee culture in Sweden and coffee contributes substantially to the environmental impact of our diet, tea is a less consumed beverage. Cocoa powder is consumed as a beverage, but substantial amounts of our cocoa consumption is in the form of chocolate. Roasted ground coffee on the Swedish market had a climate impact of 4.0 kg CO2e per kg powder, while the climate impact of instant coffee powder was 11.5 kg CO2e per kg. Per litre, including the energy use for making the coffee, the total climate impact was estimated to 0.25 kg CO2e per L brewed coffee and 0.16 kg CO2e per L for instant coffee. Less green coffee beans are needed to produce the same amount of ready to drink coffee from instant coffee than from brewed coffee. Tea had a climate impact of approximately 6.3 kg CO2 e per kg dry leaves corresponding to an impact of 0.064 CO2e per L ready to drink tea. In the assessment of climate impact per cup, tea had the lowest impact with 0.013 kg CO2e, followed by black instant coffee (0.024 kg CO2e), black coffee (0.038 kg CO2e), and cocoa drink made with milk (0.33 kg CO2e). The climate impact of 1kg cocoa powder on the Swedish market was estimated to 2.8 kg CO2e. Adding milk to coffee or tea increases the climate impact substantially. The literature describes a high proportion of the total climate impact of coffee from the consumer stage due to the electricity used by the coffee machine. However, with the Nordic low-carbon energy mix, the brewing and heating of water and milk contributes to only a minor part of the climate impact of coffee. As in previous research, coffee also had a higher land use, water use and biodiversity impact than tea per L beverage. Another factor of interest at the consumer stage is the waste of prepared coffee. Waste of prepared coffee contributes to climate impact through the additional production costs and electricity for preparation, even though the latter was small in our calculations. The waste of coffee and tea at Summary household level is extensive and measures to reduce the amount of wasted coffee and tea could reduce the environmental impact of Swedish hot drink consumption. For the final evaluation of coffee and tea for the consumer guide, the boundary for the fruit and vegetable group was used. The functional unit for coffee and tea was 1 L prepared beverage without any added milk or sweetener. In the guide, the final evaluation of conventionally grown coffee is that it is ‘yellow’ (‘Consume sometimes’), and for organic produce, ‘light green’ (‘Please consume). The evaluation of conventionally grown tea is that it is ‘light green’, and for organic produce, ‘dark green’ (‘Preferably consume this’). For cocoa, the functional unit is 1 kg of cocoa powder and the boundary was taken from the protein group. The final evaluation of conventionally grown cocoa is that it is ‘orange’ (‘Be careful’), and for organically produced cocoa, ‘light green’.
|
|
| 26. |
- Engberg, Sofie, et al.
(författare)
-
Är produktionen av biodrivmedel i Sverige hållbar? : en studie av implementering och effekt av EUs hållbarhetskriterier
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Idag är stora delar av världen beroende av fossil energi. Beroendet skapar problem eftersom förbränning av fossil energi ger upphov till växthusgaser som bidrar till ökad medeltemperatur på jorden. Ett sätt att minska beroendet och utsläppen är att ställa om till mer förnybar energi. I transportsektorn har biodrivmedel börjat användas som komplement till fossila drivmedel i det syftet. Men biodrivmedel är inte automatiskt hållbara. Beroende på hur råvarorna tas fram och hur drivmedlet framställs påverkas miljön genom växthusgasutsläpp och markbearbetning. För att stimulera en ökad produktion av hållbart producerade biodrivmedel har EU-kommissionen tagit fram Förnybartdirektivet och Bränslekvalitetsdirektivet. Syftet med den här rapporten är att beskriva lagstiftningen kring EUs hållbarhetskriterier för biodrivmedel på europeisk och nationell nivå, samt att diskutera om lagstiftningen kan bidra till en ökad efterfrågan av råvaror som producerats med lägre växthusgasutsläpp. Förnybartdirektivet anger mål för hur mycket energi som ska produceras från förnybara källor i respektive EU land samt inom EU totalt sätt. De gemensamma målen för unionen är att 20 % av den totala energiproduktionen ska komma från förnyelsebara källor samt att 10 % av de drivmedel som används inom transportsektorn ska vara förnyelsebara till år 2020. Enligt Bränslekvalitetsdirektivet ska drivmedelsleverantörer minska de totala växthusgasutsläppen per såld enhet bränsle med 6 % till år 2020 jämfört med genomsnittsutsläppen per enhet inom EU under år 2010. Biodrivmedlen måste uppfylla ett antal hållbarhetskriterier för att få räknas mot direktivens mål. Kriterierna syftar till att reglera växthusgasutsläpp och skydda mark med stor biologisk mångfald och betydande kollager. I Sverige innebär hållbarhetskriterierna i praktiken att råvara till biodrivmedel inte får tas från mark som är märkt Natura 2000 eller mark som inte var åkermark 2008. Eftersom Sverige har en minskande åkerareal sker nästan inga nyodlingar, och Natura 2000 områden används generellt inte till odling vilket gör att hållbarhetskriterierna rörande markanvändning inte har betydande effekt. De succesivt högre krav som ställs på utsläppsreduktion har dock positiv effekt då de ger branschen incitament att minska sina utsläpp. Hållbarhetskriterierna kan också ge en positiv effekt eftersom de bidrar till ökad medvetenhet och debatt om utsläpp från biodrivmedelsproduktion och jordbruk i stort. Direktiven trädde i kraft 2009 och implementerades i Sverige genom hållbarhetslagen som började gälla i juni 2010 och drivmedelslagen som började gälla i maj 2011. Definitioner och detaljer gällande hållbarhetskriteriernas innehåll och bestämmelser för beräkning av växthusgasutsläpp dröjde dock. Detta gjorde att Energimyndigheten presenterade sina föreskrifter till hållbarhetslagen först i november 2011 och vägledningen kom först under 2012., vilket gjorde att vissa aktörer drabbades av höga kostnader. Fortfarande finns det definitioner i hållbarhetskriterierna och beräkningsdetaljer i Bränslekvalitetsdirektivets artikel 7a som inte är färdiga. Osäkerheten som skapas på marknaden genom ofärdig lagstiftning kan leda till stagnation eftersom förutsättningarna för investeringar blir osäkra. I rapporten dras slutsatsen att det i teorin finns förutsättningar för råvaruproducenter att ta mer betalt för grödor som producerats med ett lägre växthusgasutsläpp. Anledningen till det är att lägre utsläpp vid produktion kan utgöra ett mervärde eftersom det sänker biodrivmedlets totala utsläpp. På grund av osäkerheten kring direktivens tillämpning efterfrågas dock inte sådana grödor just nu. Drivmedelsleverantörer (oljebolag) kan välja att sänka sina växthusgasutsläpp genom att effektivisera produktionskedjan för fossila bränslen eller genom att blanda in förnybart drivmedel i det fossila. Först när all lagstiftning är på plats kan de utvärdera vad som kommer att vara mest lönsamt för dem och då kan det eventuellt skapas efterfrågan av grödor som producerats med låga utsläpp. En annan källa till osäkerhet kring efterfrågan av grödor med låga utsläpp är debatten om indirekt förändrad markanvändning (iluc). ökad efterfrågan på råvaror till biodrivmedel kan tränga undan odling av råvaror åt matproduktion till nya geografiska områden och därmed ge upphov till indirekt förändrad markanvändning och associerade växthusgasutsläpp. Ett förslag på hur detta ska hanteras i direktiven skulle redovisas 2010 med kom först i oktober 2012. Förslaget visade sig inte bara inkludera förslag på iluc-bestämmelser utan även andra betydande ändringar i båda direktiven. Om förändringsförslaget godkänns och omsätts i lag kommer det att förändra förutsättningarna för biodrivmedelsproduktion i grunden. Slutligen, olja kommer att bli allt svårare och dyrare att utvinna i framtiden och då utvinningen blir mer komplicerad ökar också växthusgasutsläppen den ger upphov till. I det avseendet har förnybara drivmedel goda framtidsutsikter. Marknaden formas dock i hög utsträckning av politiska beslut inom handel, jordbruk och klimat. Vi behöver hitta hållbara sätt att sköta och utforma produktionen samt hur växthusgasutsläpp kan regleras i lag på ett smidigt, transparent och rättvist sätt.
|
|
| 27. |
- Eriksson, Anders
(författare)
-
A discrete-event simulation approach to improve efficiency in stump fuel supply chains
- 2014
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current concerns about climate change and fossil fuel dependency have intensified interest in renewable energy and increased demand for sustainable alternatives. Softwood tree stumps could be a very interesting renewable fuel assortment. The stump-root system constitutes about 25% of stem volume. In Sweden, stump fuel extraction is not a well-established practice and large resources are currently left in the forest after final felling. The stump fuel supply chain is both challenging and complex due to distance between resource and end-user, bulkiness of the material, initially high moisture and ash content, and number of sub-processes involved. Optimisation of logistics issues within the stump fuel supply chain is crucial to ensure low delivery cost. Carefully planned stump fuel systems can reduce the supply costs and help deliver the fuel at a competitive price. In this thesis, various systems for stump transport and comminution were evaluated, particularly regarding resource use efficiency and cutting of unnecessary costs. Various factors associated with different aspects such as harvest site characteristics, fuel quality, biomass losses and machine performance were also evaluated in terms of their impact on fuel cost. A discrete-event simulation approach was applied. Models for all machines and activities included, from forest to end-user, were developed and programmed using the ExtendSim simulation language. The simulation results showed large variations in system performance and system cost. The cost of different transport and comminution alternatives differed by approximately a factor of two, irrespective of transport distance. The most cost-effective option proved to be crushing stumps on the ground and using a self-loading truck for wood fuel transport. Minimising idle machine capacity was identified as a key factor in achieving a cost-effective system. Moreover, well-planned stump storage was shown to reduce the delivery cost significantly. The most influential parameter for fuel cost was machine productivity. Enabling machines to operate efficiently throughout the whole supply chain is crucial for system economics and can be decisive for stump fuel feasibility.
|
|
| 28. |
- Eriksson, Mattias, et al.
(författare)
-
Donera överskottsmat för att minska matsvinnet och skapa sociala värden
- 2023
-
Rapport (populärvet., debatt m.m.)abstract
- Mat som inte kan säljas kastas i stora mängder inom dagligvaruhandeln vilket innebär ett ineff ektivt utnyttjande av resurser och påfrestningar på miljön. Samtidigt finns det människor som lever under utsatta förhållanden och som saknar en säker tillgång till mat, även i ett välfärdsland som Sverige. Genom att donera överskottsmat från livsmedelsbutiker till välgörenhetsorganisationer och vidare till behövande människor kan matsvinnet minska och sociala värden skapas.
|
|
| 29. |
- Eriksson, Mattias, et al.
(författare)
-
LCAs of petrol and diesel: a literature review
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Many life cycle assessment (LCA) studies have investigated the environ-mental impact of using biofuel in transportation compared with fossil fuels. Since these studies often use standard values for the fossil fuel reference scenario, there is a need for a thorough review of published data on fossil fuel use in transportation. This study reviewed the available literature regarding greenhouse gas (GHG) emissions and energy balances in petrol and diesel use and exam-ined possible causes for the differences reported in the literature. This in-cluded differences connected to the LCA methodology itself, but also those resulting from technical and economic effects. Thirteen studies were reviewed in order to establish the level of GHG emissions and energy use in the well-to-tank perspective and, where possi-ble, in the entire well-to-wheel perspective. The studies used different input data, allocation methods and system boundaries, but the results fell within a narrow range, since the energy content of the fuels on a tank-to-wheel basis differed only slightly, while the use phase represents most GHG emissions and energy usage in fuel life cycles. All studies reviewed reported GHG emissions values that exceeded the reference value of 83.8 g CO2-eq/MJ fuel suggested in the EU Renewable Energy Directive of 2009.
|
|
| 30. |
- Eriksson, Mattias, et al.
(författare)
-
Livsmedelssvinn i butiksledet : en studie av butikssvinn i sex lågprisbutiker
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Att producera stora mängder mat är nödvändigt för att föda jordens befolkning, men dagens globala matproduktion slukar resurser och bidrar till utsläpp i stor omfattning. Ett sätt att minska denna miljöbelastning är att reducera mängden svinn som uppstår inom livsmedelskedjans alla led. Eftersom antalet delprocesser som har varit förgäves vid produktion av en vara ökar för varje led i livsmedelskedjan, ger en minskning i slutet av kedjan större effekt än motsvarande minskning i tidigare led. Butiksledet är ett av dessa senare led där det bedöms finnas potential för en minskning av svinnet. Syftet med denna studie var att kartlägga färskvarusvinnet i sex lågprisbutiker. Detta gjordes för att identifiera var svinnreducerande åtgärder kan ha störst effekt i dessa butiker samt för att få en grundnivå som de svinnreducerande åtgärdernas effekt kan jämföras med. Studien har haft som mål att skaffa erfarenheter inför vidare forskning då den ingår i ett större projekt som har som syfte att identifiera effektiva svinnreducerande åtgärder med minimal negativ påverkan på kundattityder och lönsamhet. För att uppfylla studiens syfte har sex butikers uppgifter om svinn och försäljning använts. Dessa uppgifter har sammanställts så att de olika färskvarukategoriernas variationer i svinn- och försäljningsnivå under ett år ska kunna studeras. Samtal med butikspersonal samt observationer i butikerna har kompletterat butikernas siffror för att få en mer heltäckande bild av de processer som påverkar svinnet och hur det registreras. Svinnet har, jämfört med resultat från andra studier, visat sig vara lågt med ett genomsnittligt resultat på 0,76% årligt färskvarusvinn vilket delvis förklaras av olika definitioner och systemavgränsningar mellan olika butikskedjor. Då de olika färskvaruavdelningarna har undersökts var för sig stod mejeriavdelningarna för den lägsta andelen svinn med 0,36% i genomsnitt. De högsta andelarna stod chark- och köttavdelningarna för med 1,60% respektive 1,31% genomsnittligt svinn. Variationen mellan veckorna under året var betydande liksom variationen mellan årstider. Förutom butikens eget svinn så kastas även betydande mängder mat på grund av att inkommande varor reklameras (och krediteras). Detta svinnflöde var betydligt större än flödet av butikssvinn för frukt&gröntavdelningarna. Slutsatser som går att dra av dessa resultat är att svinnreducerande åtgärder kan inriktas mot att sänka medelnivån av svinn under året. Åtgärder kan även utformas för att sänka de högsta topparna av svinn, som tex uppstår i samband med kampanjer och vid speciella tillfällen såsom högtider. Störst potential för att minska den totala mängden svinn och även krediteringssvinnet finns inom frukt&grönt då denna avdelning har ett stort viktmässigt flöde av mat som kasseras. Kött- och charkavdelningarna uppvisade ett stort procentuellt svinn och därför bör det finnas stor potential att sänka svinnet på dessa avdelningar
|
|
| 31. |
- Eriksson, Mattias, et al.
(författare)
-
Matsvinn i storkök: en analys av riskfaktorer och föreslagna åtgärder
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Matsvinn är ett problem som uppkommer längs hela livsmedelskedjan och leder till att mat produceras i onödan. Denna onödiga matproduktion bidrar till utsläpp som påverkar miljön samt förbrukar ändliga resurser. Matsvinn som uppstår i svenska storkök används ofta till att producera biogas för att ta tillvara energi och näringsämnen i maten. Trots denna återvinning är det ändå ett stort slöseri av resurser att producera bränsle av ätbar mat från slutet av värdekedjan. Därför finns ett stort behov av att förebygga matsvinn för att få en mer hållbar livsmedelskedja. Det florerar ett flertal råd om vad storkök bör göra för att minska matsvinnet eller vad de bör undvika att göra men få av dessa råd tycks ha studerats närmare för att utröna hur stor påverkan de faktiskt har på svinnet i storkök. Syftet med denna studie var därför är att undersöka om och i så fall hur mycket sex olika riskfaktorer och åtgärder påverkar matsvinnet i storkök. För att beräkna effekten av dessa riskfaktorer och åtgärder användes insamlad statistik från Sala kommun där samtliga kök inom skola, förskola och äldreomsorg ingick. Mätningarna av matsvinn kompletterades med ytterligare information om antalet ätande samt en enkätundersökning som frågade skolelever om vilka maträtter som föredrogs respektive inte föredrogs. Analysen av respektive åtgärd och riskfaktor gjordes genom att jämföra det genomsnittliga svinnet när åtgärden varit applicerad med medelvärdet då åtgärden inte varit applicerad. Av de sex riskfaktorerna och åtgärderna som analyserats i denna studie var det användandet av mottagningskök och serverandet av fler lunchalternativ än ett, som genererade mest svinn. Information till elever om mätning och att ha ett flexibelt alternativ i menyn hade en reducerande effekt på svinnet, dock var effekten inte lika stor som de två första riskfaktorerna. Att större enheter genererar mer svinn var endast sant för tallrikssvinn men totalt sett minskade svinnet något när storleken på köken ökade eftersom serveringssvinnet var lägre i stora kök. Att populära maträtter skulle resultera i extra mycket svinn kunde inte beläggas då resultaten pekade på motsatsen, nämligen att populära maträtter kasseras i mindre omfattning än opopulära maträtter. Eftersom de analyserade riskfaktorerna och åtgärderna korrelerar olika starkt med totalt svinn är en rekommendation att kommuner på lång sikt bör konvertera mottagningskök till tillagningskök, samt begränsa antalet serverade lunchalternativ. På kort sikt bör kommunerna lägga in ett flexibelt alternativ i menyn och informera elever om matsvinnsmätningar, vilket då förutsätter att mätningar faktiskt genomförs. Kommuner behöver däremot inte vara oroliga att populära maträtter eller att stora enheter ska generera mer svinn.
|
|
| 32. |
- Eriksson, Mattias, et al.
(författare)
-
Matsvinn i storkök: en kvantitativ fallstudie av måltidsverksamhet i Sala
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Matsvinn är ett problem som uppkommer längs hela livsmedelskedjan och leder till att mat produceras i onödan. Denna onödiga matproduktion bidrar till utsläpp som påverkar miljön samt förbrukar ändliga resurser. Matsvinn som uppstår i storkök används ofta till att producera biogas för att ta tillvara energin i maten, men trots denna återvinning är det ändå ett stort slöseri av resurser att producera bränsle av ätbar mat som befinner sig i slutet av värdekedjan. Därför finns det ett stort behov av att förebygga matsvinn för att få en mer hållbar livsmedelskedja. Ett första steg mot att hitta metoder för att förebygga matsvinn i storkök är att kvantifiera matsvinnet och identifiera problemområden så att olika åtgärder kan sättas in där de har störst effekt. Syftet med denna studie var därför att kartlägga kasserade kvantiteter mat för att identifiera problemområden med högt svinn. Detta genomfördes i Sala kommun där samtliga kök inom skola, förskola och äldreomsorg deltog. Mätningar av matsvinn genomfördes under tre perioder med fyra mätveckor i varje period och fokuserade främst på tallriksavskrap samt rester från serveringen. Matsvinnet jämfördes med antalet ätande gäster vilket baserades på antalet använda tallrikar. Svinnet jämfördes även med den serverade matens massa för att få fram fler relativa nyckeltal. Summerat för alla undersökta kök kasserades 75 g mat per serverad portion under mätperioden. Detta motsvarade 23 % svinn i relation till den serverade matens massa. Svinnet bestod till största delen av serveringssvinn (64 %) följt av tallrikssvinn (33 %) och övrigt (3 %). Svinnet var ojämnt fördelat och det fanns betydande variation mellan olika kök. Även beroende på vilka gäster som serverades hade betydelse för svinnet då äldreboenden hade högst svinn med 90 g per serverad portion, följt av skolköken som hade 79 g svinn per serverad portion och förskolor med 51 g svinn per serverad portion. Identifierade problemområden var främst specialkosten som var kategorin av mat vilken hade högts svinn i relation till den serverade matens massa. I övrigt var det främst skolköken som identifierade som ett problemområde då de bidrog till den största andelen av kommunens sammanlagda svinn samt hade betydligt högre svinn per serverad portion än exempelvis förskolor. Det fanns en betydande variation mellan olika kök och det är uppenbart att problemområden behöver identifieras på köksnivå snarare än på aggregerad kommunnivå för att kunna hitta åtgärder som löser de problem enskilda kök visar upp. Genom att lösa enskilda köks problem bör det finnas god potential att minska matsvinnet och därmed bidra till en mer hållbar livsmedelskedja.
|
|
| 33. |
- Eriksson, Mattias
(författare)
-
Retail food wastage : a case study approach to quantities and causes
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Food wastage is a problem along the entire food supply chain and gives rise to great financial losses and waste of natural resources. The retail stage of the supply chain contributes significant masses of waste. In order to introduce efficient waste reduction measures, the wastage problem must first be properly described. Causes of wastage need to be identified before potential measures can be designed, tested and evaluated. This thesis quantifies retail food wastage and analyse its causes with the aim of providing information that can be used to suggest potential waste reduction measures. Food wastage was quantified in six supermarkets in the Uppsala-Stockholm region of Sweden. Data were recorded during 2010 and 2011 by the retail company in a daily waste recording procedure. In addition, suppliers contributed data on deliveries and rejections. The main meat and deli supplier also contributed data on wholesale pack size and shelf-life, which allowed the relationship between these and their effect on waste to be analysed. The waste of the fresh fruit and vegetables department was dominated by the pre-store waste caused by rejections, 3.0%, whereas the in-store waste was 1.3% consisting of 1.0% recorded waste and 0.3% unrecorded waste in relation to mass delivered. Fresh fruit and vegetables waste was mainly attributable to a few products, with the eight most wasted product types contributing 67% of waste within the department. The most wasted product was tomatoes, with 106 tons of waste during the two-year test period for the six stores, followed by bananas with 90 tons and lettuce with 82 tons. Supermarket cheese, dairy, deli and meat departments all had less wasted mass and smaller percentage waste than the fruit and vegetables department. The top eight most wasted products within each of these departments contributed between 22% and 39% of the mass. Organic products were found to cause higher percentage waste than conventional products. One systematic reason for this was the lower mass sold per article for organic products. For these products, increased shelf-life and decreased minimum order size, were found to be as effective a measure for waste reduction as increased turnover.
|
|
| 34. |
- Ermolaev, Evgheni, et al.
(författare)
-
Utsläpp av växthusgaser och ammoniak från hemkomposter: inverkan av temperatur, matning och skötsel
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Hemkompostering representerar ett behandlingsalternativ för en ansenlig del av komposterbart hushållsavfall och trädgårdsavfall i Sverige. Enligt rapporten ”Svensk Avfallshantering 2010” från Avfall Sverige, var 2009 hemkomposteringens del av den totala mängden hushållsavfall som behandlades biologiskt 10 %. Det finns både positiva och negativa sidor av hemkompostering sett ur ett miljöperspektiv. Positiva effekter inkluderar användning av färdig kompost som markförbättrare, som ersättning för mineralgödsel och torv. Hemkompostering underlättar också sophanteringen och minskar avfallstransporterna vilket medför lägre utsläpp av till exempel koldioxid. De negativa effekterna är att det under komposteringsprocessen bildas växthusgaser och ammoniak som inte fångas upp och behandlas som vid vissa stora centrala anläggningar. Syftet med denna studie var att öka kunskapen om storleken på utsläppen av växthusgaser och ammoniak från hemkomposter. Undersökningen omfattade 18 hemkomposter i de södra delarna av Uppsala under perioden juni 2010 till juni 2011. Prover på kompostgas och bakgrundshalter samlades in och analyserades för att bestämma koncentrationen av koldioxid (CO?), lustgas (N?O) och metan (CH?). Ammoniakhalter (NH3) mättes direkt under locket på hemkomposterna. Materialprover analyserades med avseende på vattenhalt, askinnehåll och pH-värde. Kompostprotokoll fylldes regelbundet i av hushållen och gav information om skötseln av komposterna och mängd tillsatt material. Resultaten från mätningarna visar på låga koncentrationer av ammoniak och i många fall var halterna under detektionsgränsen (0,1 ppm). Emissionerna av metan och lustgas presenteras i form av kvoter i förhållande till koldioxid och var i medeltal 0,38 % respektive 0,15 %. Av samtliga uppmätta CH?:CO?-kvoter var 77 % lägre än 0,3 % vilket är lägre jämfört med vad som erhölls i en liknande studie av hemkompostering i Danmark. Regressionsanalysen med metan- och lustgaskvoterna som beroende variabler visade att antal omblandningar hade signifikant effekt. I övrigt hade kompostens vattenhalt och dess temperatur signifikant påverkan på CH?:CO?-kvoten, medan antal familjemedlemmar och antal dagar från senaste tillsats påverkade N?O:CO?-kvoten. Om man vill ha så låga utsläpp av växthusgaser som möjligt tyder denna studie på att man bör blanda sällan, eller inte alls, liksom att man inte bör mata sin kompost alltför mycket, så att dess temperatur stiger. Det är en fördel om temperaturen förblir låg. Utsläppen av metan skulle också bli ännu lägre om komposterna matades med torrare material.; -- Home composting represents a treatment alternative for a sizable portion of compostable household and garden waste in Sweden. According to the report “Svensk Avfallshantering 2010” by Avfall Sverige, in 2009 of all household waste handled biologically, as much as 10 % was home composted. There are both positive and negative sides of home composting when looked at from an environmental point of view. Positive effects include the use of finished compost as soil improver, substituting mineral fertilizers and peat. Additionally, emissions are avoided at composting facilitates during waste handling and waste shipments. The negative effects can potentially include high greenhouse gas and ammonia emissions. These emissions otherwise could be captured and treated at bigger facilities, thus reducing the effect on the environment. The purpose of this study was to increase knowledge about the amounts of greenhouse gases (GHGs) and ammonia being emitted from home composts. In total 18 composts in southern Uppsala were sampled between June 2010 and June 2011. Compost gas and background samples were collected and analysed to determine the concentrations of carbon dioxide (CO?), methane (CH?) and nitrous oxide (N?O). Ammonia (NH3) levels were measured directly, under the lids of home composts. Material samples were analysed for moisture content, ash content and pH. Compost protocols were regularly filled in by the households and provided the information about the management of composts and the amounts of material added. Measurement results indicated low concentrations of ammonia, which in many cases were below the detection limit (0.1 ppm). CH? and N?O emissions were presented as ratios to carbon dioxide and on the average were 0,38 and 0,15 % of CO? respectively. In 77% of composts observed, the CH?:CO? ratios were below 0,3 %, which is lower compared to a similar study on home composting performed in Denmark. The regression analysis with the methane and nitrous oxide ratios as independent variables showed that the frequency of mixing had a significant effect. Otherwise compost moisture content and temperature affected the CH?:CO? ratio, while the number of household family members and frequency of waste addition affected the N?O:CO? ratio. In conclusion, the composts which included dryer material also had lower CH? emissions. In order to reduce the GHG emissions, it could be advised to mix the compost material less or not at all, and to avoid temperature increases by regulating the amount of added waste
|
|
| 35. |
- Hammar, Torun, et al.
(författare)
-
Climate effects of a forestry company : including biogenic carbon fluxes and substitution effects
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Forestry will play an important role in a future bioeconomy, by providing wood fibres for biomaterial and bioenergy. However, there are contradictory opinions on the climate change mitigation potential of forestry. Stora Enso, an international forestry company, has the ambition to improve its climate impact assessment at corporate level.In this work, a system perspective was applied, where greenhouse gas emissions from value chains, biogenic carbon fluxes from forest land owned or leased by Stora Enso and temporarily stored in harvested wood products, and the substitution effect, i.e. avoided emissions from substituted products and energy were considered. Furthermore, new substitution factors for pulp and paper products were developed.The estimated climate effect at corporate level was a net removal of -11.5 million Mg CO2-eq yr-1 (i.e. a climate benefit) when considering value chain emissions, biogenic carbon fluxes from forest land and harvested wood products, and avoided emissions from substitution. Uptake of biogenic carbon counteracted around 40% of the value chain emissions, while the largest climate benefit (removal of 17.9 million Mg CO2-eq) was due to substitution of more greenhouse gas-intensive products.The new substitution factors developed for pulp and paper products were applied in the climate impact calculation at company level. Important assumptions and possible improvements for future studies were identified, e.g. how to assess the impact of cascading wood use in substitution calculations.
|
|
| 36. |
- Hammar, Torun, et al.
(författare)
-
Climate effects of a forestry company – including biogenic carbon fluxes and substitution effects (2021 update)
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Forestry play an important role in the bioeconomy, and will continues to do so in the future, by providing wood fibres for biomaterial and bioenergy that substitute for fossil-based alternatives, while at the same time storing carbon in forests and harvested wood products. However, there are contradictory opinions on the climate change mitigation potential of forestry. Stora Enso, an international forestry company, has the ambition to improve its climate impact assessment at corporate level. In this work, a system perspective was applied, where greenhouse gas emissions from value chains, biogenic carbon fluxes from forest land owned or leased by Stora Enso and temporarily stored in harvested wood products, and the substitution effect, i.e. avoided emissions from substituted products and energy were considered. Furthermore, new substitution factors for pulp and paper products were developed. The current report is an update of the original report, published in 2020 (Hammar et. al. 2020), based on production and value chain emissions data for the year 2021, as well as Eucalyptus plantation area as of December 2020. Overall changes in greenhouse gas fluxes relative the ones published in Hammar et al. (2020) are minor. The estimated climate effect at corporate level for 2021 is a net removal of -11.0 million Mg CO2-eq yr-1 (i.e. a climate benefit) for the year 2021 (compared to -11.5 million Mg CO2-eq yr-1 for the year 2019) when considering value chain emissions, biogenic carbon fluxes from forest land and harvested wood products, and avoided emissions from substitution. Uptake of biogenic carbon counteracted around 40% of the value chain emissions (10.2 million Mg CO2-eq yr-1), while the largest climate benefit (removal of 17.2 million Mg CO2-eq) was due to substitution of more greenhouse gas-intensive products. The same substitution factors developed in Hammar et al. (2020) for pulp and paper products were applied in the climate impact calculation at company level. Possible improvements for future studies inclued, e.g., the assessment of the impact of cascading wood use in substitution calculations.
|
|
| 37. |
- Hammar, Torun
(författare)
-
Temporal climate impacts of using willow and logging residues for district heating in Sweden
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Using bioenergy to replace fossil fuels has been adopted as a climate mitigation measure, since less greenhouse gases are expected to be released into the atmosphere. In Sweden, the share of bioenergy is relative high (about 23% of total consumption including peat), with a relatively large proportion originating from domestically produced forest biomass. This thesis examined the climate impact of using two types of woody biomass (willow, logging residues) for district heating, using time-dependent life cycle assessment methodology. The climate impact of the wood-based energy systems was determined and compared with that of the fossil fuels coal and natural gas. The focus was on the temporal dynamics of carbon fluxes between soil, biomass and atmosphere. Establishing willow on agricultural land provided the potential to sequester carbon from atmosphere to soil, giving a net cooling effect on global mean temperature. However, this effect was shown to be highly dependent on willow yield (i.e. productivity), with low yield potentially decreasing soil carbon content. Moreover, district heating from willow chips gave a lower warming effect than coal and natural gas, irrespective of yield. Combustion of forest biomass in the form of logging residues also gave a lower warming effect than coal and natural gas. However, the climate benefits compared with natural gas were delayed by 15-20 years (depending on geographical location) due to the chemical composition of natural gas, which generates less greenhouse gas emissions than coal and logging residues during extraction and combustion. Nevertheless, when decomposition of unharvested forest biomass was included in the reference systems, bioenergy from logging residues had climate benefits compared with coal and natural gas.
|
|
| 38. |
- Hassannejad, Nazir Azadeh
(författare)
-
Neurocognitive modelling of human decision making
- 2019
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A central issue related to climate change and the path to a low carbon society is how we can change our attitudes and associated behavioral patterns. This type of decisions is concerned with how complex systems can be dealt with, conceptually, psychologically, as well as socially. In order to transform our society, we need to consider the relationship between brain, mind and behavior. One of the approaches to address this problem is to design computational models that can be used for simulations and scenario building. This thesis concerns the development and application of a neurocomputational model of the decision making process of an individual at experiential and social levels, considering both emotional and rational aspects. It is an attempt to bridge the gaps between micro (neuronal), meso (brain areas) and macro (cognition/behavior) levels with a focus on the mesoscale neurodynamics of cortical structures. The model is intended to link neural structures, functions, and includes effects of internal and environmental factors. The thesis is divided into two parts, corresponding to the two kinds of decision making: 1) experience-based and 2) social-based decision making. At an individual level, a final decision is the result of an integration of rational and emotional processes. The neural structures involved in cognition valuate the potential options regarding internal attitudes and rules, as well as external contexts. Decision values are based on neural properties of activity patterns associated with different actions. The option with the highest value is selected for in the decision making process. Human behavior is guided not only by subjective values and attitudes, but also by the perceived behavior of others. Learning from/about others through observation shapes our thoughts and behavioral patterns. The second part of the thesis deals with this social adaptive characteristic of an individual, where the dynamic changes of her behaviors are connected with trust. Traces of social influences on an individual’s decisions and social expectations (e.g. trust) have been observed in the rational and emotional brain structures and their functions. While the neurocomputational model is based on anatomical and physiological data of the modeled brain structures, no real world data have been available for model validation. Yet, simulation results mimic EEG and fMRI readouts, which could be compared with experimental/clinical data, when available. Future work intends to provide such data, but currently the modeling can only provide insights in the neurodynamic interactions between brain areas involved in decision making.
|
|
| 39. |
- Hjelm, Birger
(författare)
-
Taper and volume equations for poplar trees growing on farmland in Sweden
- 2011
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Effective management of poplar plantations for high yield production would be facilitated by the availability of improved equations for predicting the taper and volume of poplar stems. Therefore, this thesis is based upon a polynomial stem taper equation and two volume equations constructed for individual poplar trees growing on farmland. Data for fitting and evaluate the taper and volume equations were collected from 51 trees growing in 27 stands in central and southern Sweden (lat. 55-60° N). The mean age of the stands was 22 years, mean density 970 stems ha⁻¹, and mean diameter at breast height 24 cm. Validation data were collected from 17 trees growing in ten stands, not used for fitting the equations. The outputs of the polynomial taper equation were compared with five published equations. The statistical evaluation indicated that the variable exponent taper equation presented by Kozak (1988) performed best and can be recommended. Because this equation´s complex construction, alternative recommendations were made. The constructed taper equation and the segmented equation presented by Max & Burkhart (1976) were second and third ranked. The first constructed stem volume equation is a function of diameter at breast height (DBH) and total height (H) as independent variables. In addition to these variables the other is also a function of an upper diameter. The outputs of these two equations were analyzed and compared to those of five published equations developed for, or applied on, poplar or aspen species. Of the stem volume equations examined the best performance was provided by the constructed equation with an additional upper diameter and recommended when precise and accurate volume estimations are required. However, because of difficulties to measure diameters high above ground, this equation is less practical in traditional surveys. For this purpose, the first constructed equation or the equation developed by Fowler & Hussain 1987 can be recommended. The taper and volume equations recommended in the study are likely to be useful in optimizing the efficiency and profitability of poplar plantation management.
|
|
| 40. |
- Johansson, Sheshti
(författare)
-
Food or fuel? : trade-offs between food and biofuels globally and in small-scale organic agriculture
- 2013
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are great expectations on agriculture to provide both food and fuels in the future. Previous attempts to estimate the global bioenergy potential have produced varying results, indicating major uncertainty. This thesis investigated the global theoretical 'potential', or limit, for biofuels based on current agricultural systems. The results showed that use of edible crops for biofuels in the current global food system would lead to a global deficit of food. Producing biofuels from residues also proved to have uncertain 'potential' and could not exceed 8 x 103 TWh. Despite the global limitations of biofuel production in the current food system, agriculture is essentially the only truly indispensable sector and may need to be independent of fossil fuels in the future due to depletion of these resources. Therefore a small-scale, low-input food system was studied to examine the effects of fuel self-sufficiency in farm work on food production and nutrient fluxes. It was found that using wheat or potatoes for ethanol production lowered food production by 23% and 18%, respectively, compared with the reference scenario of conventional diesel. The least impact on food production (94% of the reference scenario) was obtained by combining a draught horse and cold-pressed rapeseed oil produced on-farm. By producing the fuel on-farm, a larger degree of nutrient recycling could be obtained. The draught horse-rapeseed oil scenario had only a small phosphorus (P) deficit, but the potassium (K) deficit was significant in all scenarios except when potatoes were used for ethanol production. Potassium deficiency is not a problem on soils formed on sedimentary clay in Sweden, but for such alternative fuel system to be viable in other regions, some solution for recycling K will be increasingly required. Nitrogen (N) level was maintained in all scenarios due to the inclusion of N-fixing leys. The P level can be maintained in arable fields if bones are recycled. However, nutrients, especially K, are also moved from meadow to cropland.
|
|
| 41. |
|
|
| 42. |
|
|
| 43. |
|
|
| 44. |
- Johansson, Tord
(författare)
-
Biomass of sallow (Salix caprea L.)
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The amount of biomass for fractions and distribution of sallow trees growing on forest land was studied. The allometric relationship between breast height diameter (DBH) and the weight of total tree, stem, branches and leaves was quantified. The studied trees were 37±14 (5-66) years old and the stem number 1030±727 (222-3000) stems ha-1. Equations for estimating the tree weight or the fractions from diameter at breast height (DBH) are presented. The mean total standing dry weight above stump level (» 200 mm) for sallow was 95±50 tonnes ha-1 with a range of 4-203 tonnes ha-1. In addition to estimating conventional dry weights of trees and tree components, SLA and PLA, among other measures, were estimated
|
|
| 45. |
|
|
| 46. |
- Johansson, Tord
(författare)
-
Discolored stems of 12-63-year-old European aspen (Populus tremula L.).
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- European aspen (Populus tremula L.) is an inherent species in Sweden and other Nordic countries. Products from aspen are timber, pulp wood, biofuel and veneer for furniture and matches. Aspen is damaged by fungi, insects and wild habitat. Two main forms of rot are root rot (Armillaria mellea (Vahl.) Quel.) and stem rot or white heartwood rot (Phellinus tremulae (Bondartsev) Bondartsev & P.N. Borisov). But discolored wood is the most frequent form of changes in the aspen wood. In the report an overview of the factors causing discolored wood as well as the industrial use and quality of the end products is presented. The study was made at eight locations in Sweden (Lat. 65° N. Long 20° E.; Lat. 64° N. Long 19° E.; Lat. 62° N. Long 15° E.; Lat. 60° N. Long 16° E.; Lat. 60° N. Long 17° E.; Lat. 58° N. Long 14° E.; Lat. 58° N. Long 12° E.; Lat. 57° N. Long 13° E. At each of the locations five stands were evaluated. In the stand ten aspens were sampled, totally 400 aspens. Stand parameters such as stem number, diameter at breast height, height, age, forest type and soil type was registered. The age, height and diameter at breast height of the felled stem was measured. The stem was cut in sections of 1 meter. Age and diameter of the sections was registered. The stem area was examined and the diameter of discolored wood or rot was registered. The mean total age was 33±10 range 12-63 years, the mean height was 16.0±3.3 range 8.2-25.2 meter and the mean diameter at breast height was 172±28 range 81-340 mm. Most of the stands were growing on light clay till or sandy till. Among the studied 400 aspens 91 % of the stems were discolored. At 1% of stem height 91 % was discolored and 56 % at 75 % of stem height. Part of the stem, 28 %, had a discolored radius of 21 range 5-51 mm at 25 % of stem height (≈ 4 meters). The discolored volume increased with increasing breast height diameter; 10.3 % at 153 mm and 19.1 % at 350 mm. Equations describing discolored volume, %, by total stem volume were constructed. A table was also presented. These might be helpful for estimating the percentage of fresh wood in a stem.
|
|
| 47. |
- Johansson, Tord
(författare)
-
Establishment, growth and production of mixed stands planted on farmland
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Establishment growth and production of mixed stands planted on farmland In 1988 a mixed stand experiment was established on former farmland in southern Sweden, lat. 57° 57’ N., long. 12° 24’ E. Norway spruce (Picea abies (L.) and silver birch (Betula pendula Roth) was planted in pure and mixed stands. The birches were planted in pure stands and in mixed stands the same year as the spruces, one and two years after the spruces. Scots pine (Pinus sylvestris L.) and silver birch was planted with the same experimental design as for Norway spruce and silver birch. Before planting the farmland was harrowed and the area was fenced by electric wires. Totally ten treatments (parcels) were tested. The plot was 30 x 30 m with 100 seedlings in the spacing 1.5 x 1.5 m. The localization of the parcels was randomized. The treatments were replicated four times. During three years after planting dead and seriously damaged seedlings were replaced by new fresh seedlings. The trial was examined 1991, 1993, 1998, 2004, 2007 and 2011. Some of the stands were thinned 2007 or 2011. In 1998 before any removal of trees has been done the survival ranged from 29 to 87 %. The survival for Norway spruce was 77-87 %, for Silver birch 37-84 % and for Scots pine 29-87%. Between 1998 and 2002 the number of pines growing in mixed stands drastically decreased. In 2011 the mean annual increment (MAI) for Norway spruce, silver birch and Scots pine growing in pure stands was 9.5, 5.8 and 7.5 m3 ha-1 year-1 respectively. In mixed stands of birch and spruce MAI ranged between 2.8 and 6.3 for spruce and for birch 2.4 and 5.2. Based on results from the study and experiences some recommendations are presented. When planting trees in mixed stands on farmland 2500-3000 stems per hectare should be planted divided in 600-700 birches and 2000-2500 spruces. The plantation must be fenced on areas frequently visited by wild habitat.
|
|
| 48. |
- Johansson, Tord
(författare)
-
Föryngring av asp med rotbitar
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Regeneration of European aspen (Populus tremula L.) by root cuttings has been studied. Regeneration of European aspen by seeds on forest land or farmland is not efficient as the seeds are small and therefore sensitive for dryness and competition in the early stage of development. Stem and root cuttings are commonly used both as seedlings with leaves and cuttings which are planted in the field. In short rotation forestry both methods are practiced for among others: Salix and Populus (poplar and hybrid aspen). In March-April roots from 5-30-year-old aspens were sampled from four localities (Lat. 60° 16’ N. Long. 15° 59’ E.; Lat. 58° 27’ N. Long. 13° 40’ E.; Lat. 57° 55’ N. Long. 12° 21’ E. and Lat. 56° 43’ N. Long. 13° 07’ E.). The roots were cut in 10 cm long cuttings. Roots were sampled from 12 stands with 4-8 aspens in the stand totally 64 aspens. In May the root cuttings were planted on abandoned farmland in southern Sweden (Lat. 57° 55’ N. Long. 12° 21’ E.). The trial was fenced avoiding damages by wild habitat (moose, roe deer and deer). The trial was examined every autumn during seven years. The plantation was seriously damaged by wild habitat and voles in the end of year 7. Then the trial was laid down. Root cuttings from all stands still produced living sprouts after seven years. The mean diameter for all suckers at 0.1 m above ground was 13.8 (12-17) mm. The mean height for all suckers was 121.2 (106-137) cm.
|
|
| 49. |
- Johansson, Tord
(författare)
-
Growth and yield in shelter stands of silver birch and Norway spruce
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The growth and production in shelter stands of Norway spruce (Picea abies (L.) Karst.) and birches (Betula pendula Roth and Betula pubescens Ehrh.) were studied at nine areas in southern and middle Sweden (Lat. 56 – 60° N.). The spruces and birches were 25 (20 – 32) years old. Before the study was established, the stands evaluated were dense with planted spruces under self-generated birches. A birch shelter with 500 stems per hectare was created. The shelter was cut after ten years. In one stand per locality, 100 birches were left at harvesting time for further growth and development of timber quality. The MAI 20 years after treatment for pure spruce stands was 4.71 and 4.38 m3 ha-1 year-1 for spruces growing in mixed stands. The MAI for shelter birches was 4.13 m3 ha-1 year-1 and then the MAI for spruces and birches in mixed stands was 8.1 m3 ha-1 year-1. When the study was established the volume and biomass weight of the harvested birches was 107 m3 ha-1 or 84 ton d.w. ha-1 when all birches was removed and 75 m3 ha-1 or 44 ton d.w. ha-1 when a shelter of 500 birches ha-1 was left. The harvested wood could be used as biofuel. Timber could be harvested in stands where 50-100 birches ha-1 in the shelter are left. Among the remaining 100 birches per hectare in shelters examined 30 years after establishment of the study the standing volume ranged between 54 and 67 m3 ha-1.
|
|
| 50. |
- Johansson, Tord, et al.
(författare)
-
Gödsling runt poppelstubbar med stubbskott
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In 2012 three experiments on fertilization of poplar stumps was established on former farmland in southern Sweden where trial no. 1 was located at lat. 58° 08’ N., long. 12° 40’ E. and trial nos. 2 and 3 at lat. 55° 29’ N., long. 13° 39’ E. The poplar stands were 20-year-old when they were harvested in 2011. The number stems per hectare was 1250, 707 and 707 with a mean diameter at breastheight (DBH) of 24.6±0.4, 25.1±0.3 and 25.1±0.3 respectively. The diameter at 0.1 m height above stump for the sprouts was 7.5 mm in trial no.1 and 11.1 and 13.2 mm respectively for trial nos. 2 and 3. Around the stumps with a radius of 5 m the ground was fertilized in autumn 2012 with 75 and 150 kg N per hectare. Totally 30 stumps were included in each trial: 10 as a control, 10 fertilized with 75 and 150 N ha-1 each. Next year in spring 5 stumps of the fertilized stumps with 75 and 150 kg ha-1 were fertilized again with 75 and 150 kg N ha-1. The trials have been revised 2012, 2013 and 2014. The number of sprouts stump-1 three years after treatment (2014) ranged between 9 and 17 for trial no. 1. For trial nos. 2 and 3 the number ranged between 9 and 14 and 12 and 15 respectively. Fertilized stumps produced taller sprouts with higher DBH than unfertilized. Mean diameter at breastheight (DBH) was 20.7 mm for trial no. 1 and 29.9 and 33.4 mm respectively for trial nos. 2 and 3. Sprouts in trial no. 1 were shorter than in the other two trials. In trial no. 1 sprouts with repeated fertilizing 150 kg N ha-1 were tallest, 415 cm, compared with unfertilized, 335 cm. In trial nos. 2 and 3 sprouts with repeated fertilizing (150 kg N ha-1) were tallest, 592 and 584 cm compared with 516 and 548 cm for unfertilized.
|
|
