| 1. |
- Larsson, Sylvia
(author)
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Effect of process parameters and biomass composition on flat-die pellet production from underexploited forest and agricultural biomass
- 2021
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In: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 302
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Journal article (peer-reviewed)abstract
- This study investigates the impact of biomass moisture content, press-channel length, energy input, and die temperature on pellet quality in pilot-scale flat-die pellet production. In addition, observed correlations between pellet quality and the chemical composition of the pelletized biomass assortments are presented. Ten different feedstock assortments: Scots pine bark, Scots pine forest residues, willow, poplar stemwood with bark, beech stemwood with bark, wheat straw, reed canary grass, corn cobs, sunflower shells, and grape seed cakes were pelletized in a flat-die pilot-scale pelletizer with a die-channel diameter of 6 mm. The die-channel length varied within a range of 18–60 mm and biomass moisture content from 10% to 23%. In all, 72 pelletizing experiments were performed.Biomass moisture content was the most important parameter for mechanical durability. The feedstock moisture content required to obtain maximum pellet durability depended on the feedstock and showed correlations with its extractives and galactose content. For all feedstocks, bulk density correlated negatively with moisture content. The mechanical durability and bulk density of pellets increased with energy consumption. Energy consumption increased with press-channel length and was correlated with acetyl-group content.
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| 2. |
- Segerström, Markus, et al.
(author)
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Clarifying sub-processes in continuous ring die pelletizing through die temperature control
- 2014
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In: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 123, s. 122-126
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Journal article (peer-reviewed)abstract
- A pilot scale pelletizer with a custom-made die temperature control system was used for pelletizing of a typical Nordic softwood blend in an experimental design where die temperature, moisture content, and steam conditioning were varied independently. Steam conditioning, expressed as material temperature, showed a strong negative correlation with the pelletizer motor current, but had no significant effect on other responses. Die temperature was negatively correlated to bulk density and durability. This negative correlation is contradictory to results from a pilot scale study where die temperature co-varied with other factors, and to results from single pelletizing studies that do not mimic the friction originated pressure build-up that is required for pellet formation (C) 2014 Elsevier B.V. All rights reserved.
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| 3. |
- Larsson, Gunnar
(author)
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Potential för bränslebesparingar genom hybridisering av hjullastare
- 2012
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Reports (other academic/artistic)abstract
- I projektet har studerats hur olika faktorer påverkar möjligheterna till bränslebesparing genom hybridisering. Hur pass stor denna minskning blir beror på en stor mängd variabler som hur fordonet används, miljön det används i (t.ex. rullmotstånd) och själva fordonet. De variabler som har störst inverkan på de potentiella bränslebesparingarna genom hybridisering är: rullmotstånd, maxhastighet, längd på cykeln. Genom hybridisering kan energiförbrukningen teoretiskt minska med omkring 60 % för den ”korta cykeln” under de flesta förhållanden för vilken modellen använts. Vid längre cykellängd minskar potentialen för bränslebesparingar. Om alla interna förluster kan undvikas (vilket kan ses som ett teoretiskt extremfall som steg för steg närmas vid full elektrifiering) är en minskning på omkring 80 % teoretiskt möjligt. Den reellt genomförbara minskningen beror även på hastighet på inbromsningen samt de ingående elektriska komponenternas verkningsgrad och förmåga att hantera effekt. Med nuvarande komponentprestanda och prisnivåer är den begränsande faktorn lagringsmediet. Det som begränsar är dess förmåga att ta emot effekt. Detta göra att för närvarande är superkondensatorer det mesta intressanta alternativet för energilagring för hybridhjullastare.
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| 4. |
- Lideskog, Håkan, et al.
(author)
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Development of a research vehicle platform to improve productivity and value-extraction in forestry
- 2015
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In: Procedia CIRP. - : Elsevier BV. - 2212-8271 .- 2212-8271. ; 38, s. 68-73
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Journal article (peer-reviewed)abstract
- In spite of the high level of mechanization in most forestry operations there is a continuedneed for improvements in productivity and cost effectiveness. Automation of mechanised operations isone possible solution to achieve such improvements but new techniques that can acquire informationfrom the surroundings and make proper analyses rendering in streamlined or new work proceduresare prerequisites. Furthermore, product producers buying forest biomaterials often have certainquality wishes. As an addition to automatic work procedures, new technology can further be used toretrieve information for identification and selection of certain tree assortments with differentbiomaterial properties. In this way, performance-based delivery of tree biomaterial extracted withhighly automated work procedures has the possibility to be an enabler to continue the productivitydevelopment progress in the forest sector. The objective for this paper is therefore to summarizepossible technical needs for and to design an experimental research vehicle platform for academia andmachine developers to test and validate new solutions that could improve cost effectiveness inforestry. The platform is designed specifically to test and validate various control systems forautonomy and robotics and also to enable tests and validation of attachments, e.g. to enable betterplanting procedures or identification of trees with certain properties. Sensors are embedded in theplatform to register angles, rotation speed, etc., thus actualising machine automation as an enabler forperformance-based delivery of planting or of tree biomaterial assortments.
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| 5. |
- Olausson, Inger, 1969-
(author)
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Market gardens in Sweden 1900-1950 with four case studies from Stockholm County
- 2015
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In: ISHS Acta Horticulturae 1108XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): V International Conference on Landscape and Urban Horticulture and International Symposium on Sustainable Management in the Urban Forest. - : International Society for Horticultural Science. - 9789462611023 ; 1108, s. 123-129
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Conference paper (other academic/artistic)abstract
- The links between market gardens and cities were symbiotic until the mid-1900s. In my thesis about market gardens in Sweden 1900-1950, four market gardens in Stockholm County are investigated, trying to find out how different resources and strategies contributed to the businesses competitiveness. Two of the market gardens belonged to mansions with all the staff employed. The other two were established as family businesses by entrepreneurs without employees. Garden products are sensitive to bumps, heat, low temperatures, etc. Due to this, the access to a nearby market was necessary at that time. The development of the trade with garden products was linked to a fast-growing population in the cities, the growing demand for garden products, and the development of the transport sector. From the growing city, gardeners bought horse manure, garbage, or anything that produced heat to the hotbeds when it decomposed. Most of the market gardens were small family businesses situated on small plots. In the 1930s and 1940s in 75% of the businesses a maximum of three people were engaged. The production was both resource-demanding and labour-intensive. The use of hotbeds and greenhouses extended the growing season and made it possible to grow all year around. The gardenerRSQUOs dependence on merchandises increased like an avalanche to beat the growing competition on the market. The import, often of high quality products, was growing very fast and affected the interest for garden products. It forced the domestic horticulture industry to increase the quality and effectiveness of the production.
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| 6. |
- Edlund, Jeanette, et al.
(author)
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A long-tracked bogie design for forestry machines on soft and rough terrain
- 2013
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In: Journal of terramechanics. - : Elsevier. - 0022-4898 .- 1879-1204. ; 50:2, s. 73-83
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Journal article (peer-reviewed)abstract
- A new design for a tracked forestry machine bogie (long track bogie; LTB) on soft and rough terrain is investigated using nonsmooth multibody dynamics simulation. The new bogie has a big wheel that is connected to and aligned with the chassis main axis. A bogie frame is mounted on the wheel axis but left to rotate freely up to a maximum angle and smaller wheels that also rotate freely are mounted on the frame legs with axes plane parallel to the driving wheel. The wheels are covered by a single conventional forestry machine metal track. The new bogie is shown to have higher mobility and cause less ground damage than a conventional tracked bogie but requires larger torque to create the same traction force as a conventional bogie. The new bogie also gives less acceleration when passing obstacles than the conventional bogie. Additionally, due to the shape and size of the new bogie concept, it can pass wider ditches.
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| 7. |
- Hinchcliffe, James, 1992, et al.
(author)
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Comparative survival and growth performance of European lobster Homarus gammarus post-larva reared on novel feeds
- 2020
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In: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 51:1, s. 102-113
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Journal article (peer-reviewed)abstract
- One approach to ongrow juvenile European lobster, Homarus gammarus, is to utilize land based rearing systems, incorporating automated feeding, individual culture and provision of stable pelleted feeds, preferably using sustainable ingredients. We initiated three feeding experiments to investigate the general suitability of ingredients produced from seafood by-products as novel feeds for H. gammarus, in terms of promoting survival, development and growth of post-larval lobsters from post-larvae (PL) stage IV to the first juvenile stage (stage V). The first experiment was designed to screen an array of candidate, locally produced, novel protein sources on growth performance parameters. This initial experiment revealed that PL reared on a raw (i.e. wet, unprocessed shrimp) feed used as a reference showed superior performance to those reared on experimental feeds containing fishmeal, herring protein isolate or mussel meal; however, a novel type of shrimp meal, produced by flocculation from waste water, promoted the best PL performance of any experimental feed. A second experiment was designed to test the effect of drying method and to optimize the form of a wet shrimp reference feed used by lobster hatcheries. This showed that the performance of PL reared on experimental freeze-dried shrimp feed was not significantly different to those reared on the wet, unprocessed shrimp used as a reference feed. However, lobsters offered experimental oven-dried shrimp feed (with or without an immune supplement) resulted in significantly lower survival or growth performance. A third and final experiment was designed in an attempt to improve a candidate herring-based protein source, by supplementing with nutrients found in shrimp. However, the results showed that PL reared on the wet reference shrimp feed still showed superior growth and survival than those reared on a herring feed alone, or supplemented with additives found in shrimp meal (either glucosamine, astaxanthin or both supplements combined). The high survival and growth, low incidence of moulting problems and high availability of waste shrimp material, suggest that non-heat-treated shrimp products are a promising feed ingredient for post-larval European lobsters.
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| 8. |
- Afshar, Reza, et al.
(author)
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Creep in oak material from the Vasa ship: : verification of linear viscoelasticity and identification of stress thresholds
- 2020
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In: European Journal of Wood and Wood Products. - : Springer Nature. - 0018-3768 .- 1436-736X. ; 78:6, s. 1095-1103
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Journal article (peer-reviewed)abstract
- Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confrm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress–strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were ftted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress–strain relationships were used to defne a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3–0.5 MPa in the R direction and 0.05–0.2 MPa in the T direction.
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| 9. |
- Edlund, Jeanette
(author)
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Harvesting in the boreal forest on soft ground : ways to reduce ground damage
- 2012
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Licentiate thesis (other academic/artistic)abstract
- The overall aim of the studies underlying this thesis has been to acquire knowledge relating to potential methods of reducing both the amount and severity of ground damage caused by forest machinery used in the boreal forest. The work focused on technical solutions applied to the forwarders that had the potential to reduce ground damage such as rutting and soil compaction. Additionally, the work focused on detecting areas that had a weak bearing capacity, using terrain indices based on digital elevation models and pre-existing forestry register data. In paper I, it was shown that by combining forestry register data and terrain indices to find the Rammsonde pressure on till soil, 73% of the measurements correctly classified low or high bearing capacity ground. In paper II, a forwarder with individually steerable wheels was described that, compared to a conventional forwarder, formed shallower ruts when driving in a straight line on forest land and made narrower ruts when turning on both forested land and arable land. When driving in a straight line on soft soil with or without load, the ruts from the conventional forwarder were shallower. In paper III, simulations showed that the new Long Track Bogie (LTB), with a bearing capacity dependent contact area, negotiates low obstacles more smoothly than a conventional bogie and can handle wider ditches. The soil displacement from the LTB is also smaller when turning. In live tests on firm ground, the mean towing force for the LTB was 62% higher than for the conventional bogie and the rolling resistance was higher for the conventional bogie compared to the LTB (paper IV). The results indicate that it is possible to reduce ground damage when harvesting by developing forest machines with steering and transmission drive systems that minimize damage on both soft and firm ground and by developing planning tools that predict the soil bearing capacity at the stand level. This might allow a classification of the ground without visiting the forest site and thus facilitate the choice of appropriate forest machines.
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| 10. |
- Fernqvist, Fredrik, et al.
(author)
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What’s in it for me? Food packaging and consumer responses in a focus group study
- 2015
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In: British Food Journal. - 0007-070X .- 1758-4108. ; 117:3, s. 1122-1135
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Journal article (peer-reviewed)abstract
- Purpose – This study has three broad objectives: (1) to explore consumer views on different dimensions of consumer packaging when it comes to a common staple food; (2) to discuss the role of different packaging features in consumer choice; (3) to compare consumer views on purchasing a common staple food either as an undifferentiated anonymous commodity or as a differentiated product.Design/methodology/approach – Three semi-structured focus group interviews were conducted. A thematic analysis was made by means of a theory driven approach. Six different packaging was used as discussion material, to headlight and exemplify different aspects.Findings - The analysis revealed consumer views in eight categories of packaging features regarding a common staple food (potato) being (1) packaging material, (2) packaging size, (3) protection and preservation, (4) convenience, (5) price, (6) communication and information, (7) ethical perspectives, and (8) novelty and innovation. The role of packaging features in consumers’ choice is discussed, and comparisons are made with the alternative of an undifferentiated anonymous product. Positive and negative aspects were found in both cases.Research limitations/implications – This research contributes to present knowledge regarding packaging dimensions of fast moving consumer goods, and provides insights on consumers’ views on both packaged products and the alternative of an undifferentiated commodity. Limitations and advantages of using focus groups are discussed.Practical implications – The findings add to knowledge of consumer behaviour and food choice as regards consumer packaging and consumer views on both an undifferentiated commodity, and added packaging to diversify the product. The findings are applicable by practitioners in the industry of fast moving consumer goods. The paper suggests areas for future research.Originality/value – This study uses a common everyday staple to compare consumer views on both a differentiated product by the means of packaging, and the product as being undifferentiated and anonymous. By comparing two levels of differentiation, this study provides insights in consumer standpoints regarding packaging issues, and their views on just the actual product as commodity.
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