| 1. |
- Nilsson, Lars, et al.
(författare)
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The molecular signature of MDS stem cells supports a stem-cell origin of 5q-myelodysplastic syndromes
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:8, s. 3005-3014
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Tidskriftsartikel (refereegranskat)abstract
- Global gene expression profiling of highly purified 5q-deleted CD34+CD38–Thy1+ cells in 5q– myelodysplastic syndromes (MDSs) supported that they might originate from and outcompete normal CD34+CD38–Thy1+ hematopoietic stem cells. Few but distinct differences in gene expression distinguished MDS and normal stem cells. Expression of BMI1, encoding a critical regulator of self-renewal, was up-regulated in 5q– stem cells. Whereas multiple previous MDS genetic screens failed to identify altered expression of the gene encoding the myeloid transcription factor CEBPA, stage-specific and extensive down-regulation of CEBPA was specifically observed in MDS progenitors. These studies establish the importance of molecular characterization of distinct stages of cancer stem and progenitor cells to enhance the resolution of stage-specific dysregulated gene expression.
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| 2. |
- Ainegren, Mats, 1963-, et al.
(författare)
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A Study of Skin-Close Heat and Moisture with Different Types of Backpacks in Cycling
- 2020
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Ingår i: The 13th Conference of the International Sports Engineering Association. - Basel Switzerland : MDPI.
-
Konferensbidrag (refereegranskat)abstract
- The aim of this project was to evaluate effects of backpacks with different design intended for use during cycling on skin-close temperature and relative humidity, oxygen uptake, heart rate and aerodynamic drag. Seven subjects took part in the study cycling on a mountain bike mounted on a “smart trainer” placed on a force plate in a wind tunnel. Three series of experiments were carried out: without backpack, with conventional backpack and with a backpack having innovative rear panel design. As hypothesized, the results showed that an innovatively designed backpack with the ducts deflecting part of the airflow towards some areas of the user’s back provided lower temperature and relative humidity for the microclimate compared to a conventional backpack without airflow channels. Further, reference tests without any backpack resulted in the lowest temperature and humidity. However, no differences were found between the three tests for oxygen uptake, heart rate and aerodynamic drag.
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| 3. |
- Bernesson, Sven, et al.
(författare)
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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
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| 4. |
- Cheng, Shi, et al.
(författare)
-
Switched beam antenna based on RF MEMS SPDT switch on quartz substrate
- 2009
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225 .- 1548-5757. ; 8, s. 383-386
-
Tidskriftsartikel (refereegranskat)abstract
- This letter demonstrates a 20-GHz radio frequency microelectromechanical system (RF MEMS)-based electrically switchable antenna on a quartz substrate. Two quasi-Yagi antenna elements are monolithically integrated with a single-pole double-throw (SPDT) MEMS switch router network on a 21 mm x 8 mm chip. Electrical beam steering between two opposite directions is achieved using capacitive MEMS SPDT switches in the router. Port impedance and radiation patterns are studied numerically and experimentally. Measured results show that the switched beam antenna features a 27% impedance bandwidth (S-11 = -10 dB), a gain of 4.6 dBi, and a front-to-back ratio of 14 dB at 20 GHz when the control voltage is applied to one of the switch pairs of the SPDT switch.
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| 5. |
- Dancila, Dragos, et al.
(författare)
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Wide Band On-Chip Slot Antenna with Back-Side Etched Trench for W-band Sensing Applications
- 2013
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Ingår i: 2013 7th European Conference on Antennas and Propagation (EuCAP). - 9788890701832 ; , s. 1576-1579
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the design and characterization of a highly integrated, wideband on-chip radiometer, composed of a slot antenna, RF-MEMS Dicke Switch, LNA and a wideband power detector. The highly integrated single-chip RF front-end is dedicated for broadband sensing up to 110 GHz. Both antenna and radiometer are fabricated in a 0.25 mu m SiGe BiCMOS process. The antenna design takes benefit of the back-side etched trench, offered by the technology. This is used to reduce losses due to the presence of the low resistivity silicon substrate. Additionally, the trench is specially shaped, as to improve the wideband matching of the antenna. The on-chip slot antenna design covers a wide bandwidth (70-110 GHz) with 0 dBi gain and 64% efficiency, both simulated at 94 GHz. The measured bandwidth spans 85 to 105 GHz. The W-band SiGe detector circuit has close to 20 GHz of operational bandwidth (S-11 <=-10 dB at 75-92 GHz) and presents a responsivity of 3-5kV/W (NEP=10-16 pW/Hz(1/2)) at 83-94 GHz.
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| 6. |
- Dupont, Chris L., et al.
(författare)
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Functional Tradeoffs Underpin Salinity-Driven Divergence in Microbial Community Composition
- 2014
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:2, s. e89549-
-
Tidskriftsartikel (refereegranskat)abstract
- Bacterial community composition and functional potential change subtly across gradients in the surface ocean. In contrast, while there are significant phylogenetic divergences between communities from freshwater and marine habitats, the underlying mechanisms to this phylogenetic structuring yet remain unknown. We hypothesized that the functional potential of natural bacterial communities is linked to this striking divide between microbiomes. To test this hypothesis, metagenomic sequencing of microbial communities along a 1,800 km transect in the Baltic Sea area, encompassing a continuous natural salinity gradient from limnic to fully marine conditions, was explored. Multivariate statistical analyses showed that salinity is the main determinant of dramatic changes in microbial community composition, but also of large scale changes in core metabolic functions of bacteria. Strikingly, genetically and metabolically different pathways for key metabolic processes, such as respiration, biosynthesis of quinones and isoprenoids, glycolysis and osmolyte transport, were differentially abundant at high and low salinities. These shifts in functional capacities were observed at multiple taxonomic levels and within dominant bacterial phyla, while bacteria, such as SAR11, were able to adapt to the entire salinity gradient. We propose that the large differences in central metabolism required at high and low salinities dictate the striking divide between freshwater and marine microbiomes, and that the ability to inhabit different salinity regimes evolved early during bacterial phylogenetic differentiation. These findings significantly advance our understanding of microbial distributions and stress the need to incorporate salinity in future climate change models that predict increased levels of precipitation and a reduction in salinity.
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| 7. |
- Enmark, Martin, et al.
(författare)
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A systematic investigation of algorithm impact in preparative chromatography with experimental verifications
- 2011
-
Ingår i: Journal of Chromatography A. - Amsterdam : Elsevier. - 0021-9673 .- 1873-3778. ; 1218:5, s. 662-672
-
Tidskriftsartikel (refereegranskat)abstract
- Computer-assisted optimization of chromatographic separations requires finding the numerical solution of the Equilibrium-Dispersive (ED) mass balance equation. Furthermore, the competitive adsorption isotherms needed for optimization are often estimated numerically using the inverse method that also solves the ED equations. This means that the accuracy of the estimated adsorption isotherm parameters explicitly depends on the numerical accuracy of the algorithm that is used to solve the ED equations. The fast and commonly used algorithm for this purpose, the Rouchon Finite Difference (RFD) algorithm, has often been reported not to be able to accurately solve the ED equations for all practical preparative experimental conditions, but its limitations has never been completely and systematically investigated. In this study, we thoroughly investigate three different algorithms used to solve the ED equations: the RFD algorithm, the Orthogonal Collocation on Finite Elements (OCFE) method and a Central Difference Method (CDM) algorithm, both for increased theoretical understanding and for real cases of industrial interest. We identified discrepancies between the conventional RFD algorithm and the more accurate OCFE and CDM algorithms for several conditions, such as low efficiency, increasing number of simulated components and components present at different concentrations. Given high enough efficiency, we experimentally demonstrate good prediction of experimental data of a quaternary separation problem using either algorithm, but better prediction using OCFE/CDM for a binary low efficiency separation problem or separations when the compounds have different efficiency. Our conclusion is to use the RFD algorithm with caution when such conditions are present and that the rule of thumb that the number of theoretical plates should be greater than 1000 for application of the RFD algorithm is underestimated in many cases
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| 8. |
- Enmark, Martin, et al.
(författare)
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Computer Assisted Optimization of Pharmaceutical Purification - The Impact of Algorithms and Experimental Approach
- 2010
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Konferensbidrag (refereegranskat)abstract
- Computer assisted process optimization of chromatographic separations requires the selection of computer algorithms and measurement of relevant parameters. In this study, we will investigate how the choice of algorithms and the number of performed initial experiments affect the estimated optimal separations conditions. We will focus on conditions typically encountered for slurry packing coated 20 µm CSP in large-scale columns used for pharmaceutical intermediate purification.Probably the most essential for parameters in this context are the adsorption isotherm parameters for the components. The rapid "inverse method" is commonly used and this method requires that one numerically solve the mass balance equations describing the chromatographic process. Here we thoroughly investigate how different algorithms that solve the Equilibrium-Dispersive (ED) mass balance equations will affect the estimated adsorption isotherm parameters.Furthermore, we will investigate and compare how different strategies affect the prediction of the optimal separation conditions. First, we will use a more rapid approach that requires a minimum of experiments and uses standard algorithms to estimate optimal conditions. Secondly, we will use a more exact approach that requires more experiments and uses more advanced simulation- and optimization algorithms
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| 9. |
- Feldt, Robert, et al.
(författare)
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Links between the personalities, views and attitudes of software engineers
- 2010
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Ingår i: Information and Software Technology. - : Elsevier BV. - 0950-5849 .- 1873-6025. ; 52:6, s. 611-624
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Tidskriftsartikel (refereegranskat)abstract
- Context:Successful software development and management depends not only on the technologies, methods and processes employed but also on the judgments and decisions of the humans involved. These, in turn, are affected by the basic views and attitudes of the individual engineers.Objective:The objective of this paper is to establish if these views and attitudes can be linked to the personalities of software engineers.Methods:We summarize the literature on personality and software engineering and then describe an empirical study on 47 professional engineers in ten different Swedish software development companies. The study evaluated the personalities of these engineers via the IPIP 50-item five-factor personality test and prompted them on their attitudes towards and basic views on their professional activities.Results:We present extensive statistical analyses of their responses to show that there are multiple, significant associations between personality factors and software engineering attitudes. The tested individuals are more homogeneous in personality than a larger sample of individuals from the general population.Conclusion:Taken together, the methodology and personality test we propose and the associated statistical analyses can help find and quantify relations between complex factors in software engineering projects in both research and practice.
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| 10. |
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| 11. |
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| 12. |
- Fellström, Bengt, et al.
(författare)
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Rosuvastatin and cardiovascular events in patients undergoing hemodialysis.
- 2009
-
Ingår i: The New England journal of medicine. - 1533-4406 .- 0028-4793. ; 360:14, s. 1395-407
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Statins reduce the incidence of cardiovascular events in patients at high cardiovascular risk. However, a benefit of statins in such patients who are undergoing hemodialysis has not been proved. METHODS: We conducted an international, multicenter, randomized, double-blind, prospective trial involving 2776 patients, 50 to 80 years of age, who were undergoing maintenance hemodialysis. We randomly assigned patients to receive rosuvastatin, 10 mg daily, or placebo. The combined primary end point was death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. Secondary end points included death from all causes and individual cardiac and vascular events. RESULTS: After 3 months, the mean reduction in low-density lipoprotein (LDL) cholesterol levels was 43% in patients receiving rosuvastatin, from a mean baseline level of 100 mg per deciliter (2.6 mmol per liter). During a median follow-up period of 3.8 years, 396 patients in the rosuvastatin group and 408 patients in the placebo group reached the primary end point (9.2 and 9.5 events per 100 patient-years, respectively; hazard ratio for the combined end point in the rosuvastatin group vs. the placebo group, 0.96; 95% confidence interval [CI], 0.84 to 1.11; P=0.59). Rosuvastatin had no effect on individual components of the primary end point. There was also no significant effect on all-cause mortality (13.5 vs. 14.0 events per 100 patient-years; hazard ratio, 0.96; 95% CI, 0.86 to 1.07; P=0.51). CONCLUSIONS: In patients undergoing hemodialysis, the initiation of treatment with rosuvastatin lowered the LDL cholesterol level but had no significant effect on the composite primary end point of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. (ClinicalTrials.gov number, NCT00240331.)
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| 13. |
- Finell, Michael, et al.
(författare)
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Lagring av pellets – inverkan på kvalitet : fullskaleförsök hos Agroenergi Neova Pellets AB i Malmbäck : pelletplattformen II
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Huvudsyftet med detta försök var att undersöka hur pelletskvaliteten förändras vid lagring av 6 mm och 8 mm pellets och om tillsats av stärkelse (0,5 %) påverkar lagringsegenskaperna och pelletskvaliteten. Tio satser (högar) om totalt cirka 10 ton pellets bereddes. Sex högar med 8 mm pellets och fyra högar med 6 mm pellets. Pelletarna var tillverkade vid hög fukthalt respektive låg fukthalt. 6 mm pellets tillverkades endast med tillsats av stärkelse medan 8 mm pellets tillverkades både med och utan tillsats. Högarna lagrades i en plansilo under 37 dagar. I varje hög placerades dataloggrar som samlade in data om hur temperaturen förändrades under lagring. Pelletskvaliteten, d.v.s. bulkdensitet, hållfasthet, andel finfraktion och pelletsfukthalten mättes både på färska, nyproducerade pelletar och på lagrat material vid försökets slut. Försöket visade att självuppvärmningsbenägenheten var tydligt kopplad till fukthalten på de producerade pelletarna. En låg fukthalt gav betydligt högre temperatur i pelletshögarna. Maximal temperatur uppnåddes efter ca 3 dagars lagring. Pelletskvaliteten förändrades genom att hållfastheten ökade något efter lagring. Fukthalten på pelletarna ökade också något efter lagring men denna skillnad var mycket liten. Användning av stärkelseadditiv vid pelletstillverkning ökade hållfastheten på produkten men hade i övrigt ingen effekt på lagringsegenskaperna.
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| 14. |
- Finell, Michael, et al.
(författare)
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Lagring av pellets – inverkan på kvalitet och emissionsbildning : fullskaleförsök vid SCA BioNorr AB i Härnösand : pelletplattformen II
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Huvudsyftet med detta försök var att undersöka hur pelletskvaliteten, emissioner av aldehyder (associerad med stark lukt) och emissioner av CO, CO2, CH4 förändras vid lagring av 6 mm och 8 mm pellets. Sex satser (högar) om totalt cirka 10 ton pellets bereddes. Tre högar med 8 mm pellets och tre högar med 6 mm pellets. Pelletarna var tillverkade vid hög fukthalt respektive låg fukthalt. En upprepning med 8 mm pellets och en upprepning med 6 mm pellets ingick i försöket. Högarna lagrades i en plansilo under 32 dagar. Inne i varje hög placerades en 1m3 gastät behållare (Cipaxtank) som fyllts med ca 500 kg (ca 70 % av volymen) pellets. Provtagning av CO, CO2 och CH4 gjordes kontinuerligt och andelen aldehyder mättes med hjälp av passiva provtagare inne i Cipaxtankarna. I högarna och i den omgivande lokalen placerades också temperatur- och fuktloggar för att följa hur temperaturen förändrades under försöksperioden. Prover av pellets togs ut ur högarna vid försökets start och vid försökets slut. Dessa prover analyserades med avseende på andel finmaterial, hållfasthet, bulkdensitet och fukthalt. Resultaten visade att andelen finmaterial ökar under lagring samtidigt som hållfastheten på pelletarna ökar. Temperaturökningen i högarna verkar vara kopplade till fukthalten på de producerade pelletarna så att en låg fukthalt ger högre temperatur vid lagring. Aldehydbildningen och emissionen av CO, CO2 och CH4 i kombination med minskningen av O2 tyder på att autooxidation av materialet sker vid lagring. Ingen större skillnad mellan 6 mm och 8 mm pellets kunde detekteras varken med avseende på fysikaliska pelletsegenskaper eller emissioner.
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| 15. |
- Finell, Michael, et al.
(författare)
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Pelleteringsförsök med återvunnet trädbränsle : fullskaleförsök vid Helsinge Pellets AB i Edsbyn : pelletplattformen II
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Huvudsyftet med detta försök var att jämföra återvunnet trädbränsle med den vanliga råvaran (spånblandning, ca 50/50 av gran och tall) med avseende på processbarhet och pelletskvalitet. Försöket utfördes i full skala hos Helsinge Pellets ABs fabrik i Edsbyn. Pellets producerades vid 3 olika fukthalter på det torkade RT-spånet och på den vanliga råvaran. Fukthalterna på spånet efter torkning varierades mellan 6 % och 15 %. Prover av spån togs ut innan pressarna samt av pellets producerade vid de olika fukthalterna direkt efter pelletspressen. Alla prover transporterades till SLU i Umeå direkt efter produktion för analys av hållfasthet, andel finmaterial, bulkdensitet samt emissioner vid lagring. Försöket visade att det återvunna trädbränslet innehåller stora mängder metall, stenar och glas som inte är önskvärda att följer med i processen. Materialet går dock att hantera i processen och de pellets som producerades hade samma hållfasthet som pellets producerade av vanlig råvara. Bulkdensiteten för pellets producerade av återvunnet trädbränsle var dock något lägre än för pellets producerade av vanlig råvara. Askhalten i det återvunna trädbränslet varierade mycket men var minst 10 gånger högre än i den vanliga råvaran. Lagringsförsök i laboratorieskala visade att emissionerna av koloxid, koldioxid och metan av pellets från återvunnet trädbränsle var betydligt lägre jämfört med pellets tillverkade av vanlig råvara.
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| 16. |
- Finell, Michael, et al.
(författare)
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Pelletplattformen II – slutrapport 2012-2016
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Målet med projektet pelletplattformen II har varit att produktionskostnaderna ska minskas med minst 0,5 % per år (upp till 5 % år 2020) vid storskalig förädling av pellets genom effektivare process, minskat slitage, minskad energiåtgång, minskat spill, etc. Vidare syftade projektet till att ytterligare bredda råvarubasen för pelletskvaliteter för olika ändamål med en omvandlingsteknik anpassad till nya bränslen, så att fler bränslekedjor kan nå marknaden och klarar ställda miljökrav och hållbarhetsmål. Vi har visat att man genom att höja fukthalten på produkten med en eller två procentenheter kan stora mängder torkenergi sparas. En ökad fukthalt ger förutom energibesparingar möjlighet att bättre optimera pelletskvaliteten med avseende på hållfasthet och smulhalt samt dessutom minskar risken för varmgång vid lagring. Även stora mängder elenergi, upp till 6,5 % av pelletsindustrins elförbrukning enligt våra uppskattningar, kan sparas genom att sålla spånet innan pelletering och endast mala den övergrova fraktionen. Inblandning av asp eller salix i råvarumixen kan ge positiva effekter på pelletskvaliteten. Additiv som stärkelse och lignosulfonat gör det möjligt att öka hållfastheten och minska smulbildning vid pelletstillverkningen. Det är också möjligt att minska emissioner av CO, CO2 och CH4 genom användning av additiv eller genom att modifiera råvaran med superkritisk koldioxidextraktion.
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| 17. |
- Finell, Michael, et al.
(författare)
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Smulåterföring – inverkan på pelletskvalitet : fullskaleförsök vid Bioenergi Luleå AB
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I detta försök har inverkan av smulåterföring på process produktkvalitet studerats vid pelletstillverkning i full skala hos Bioenergi i Luleå AB. I processen återförs normalt det smul som avskiljs direkt efter kylning av produkten till torrmaterialsilon innan pressarna. I denna undersökning har vi studerat hur processen och pelletskvaliteten förändras om man istället för att återföra smul helt tar bort det smul som bildas. Inom försöket undersöktes också inverkan av råvarans torrhalt och matning av spån till pressen (produktionshastighet) på process och pelletskvalitet. Försöken visade att smulåterföringen har en signifikant inverkan på hur mycket finfraktion som bildas vid pelletstillverkningen, på pelletarnas hållfasthet samt på strömstyrkan (och energiåtgången) för pelletspressarna. Skillnaderna i hållfasthet och strömstyrka var dock små. Utan smulåterföring minskade andelen bildad finfraktion vid pressningen med i medeltal 14 %. Råvarans torrhalt och matningen till pressarna hade i många fall större inverkan än smulåterföringen och dessa parametrar var av signifikant betydelse för alla undersökta egenskaper.
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| 18. |
- Forsberg, Camilla, et al.
(författare)
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Bystanders to bullying : Fourth- to seventh-grade students' perspectives on their reactions
- 2014
-
Ingår i: Research Papers in Education. - : Routledge. - 0267-1522 .- 1470-1146. ; 29:5, s. 557-576
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Tidskriftsartikel (refereegranskat)abstract
- The aim with the present study was to investigate bystander actions in bullying situations as well as reasons behind these actions as they are articulated by Swedish students from fourth to seventh grade. Forty-three semi-structured individual interviews were conducted with students. Qualitative analysis of data was performed by methods from grounded theory. The analysis of the student voices of being a bystander in bullying reveals a complexity in which different definition-of-situation processes are evoked (a) relations (friends and social hierarchy), (b) defining seriousness, (c) victim’s contribution to the situation, (d) social roles and intervention responsibilities, and (e) distressing emotions. There are often conflicted motives in how to act as a bystander, which could evoke moral distress among the students. Our analysis is unique in that it introduces the concept of moral distress as a process that has to be considered in order to better understand bystander actions among children The findings also indicate bystander reactions that could be associated with moral disengagement, such as not perceiving a moral obligation to intervene if the victim is defined as a non-friend (‘none of my business’), protecting the friendship with the bully, and blaming the victim.
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| 19. |
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| 20. |
- Forsberg, Camilla, 1983-
(författare)
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Students’ Perspectives on Bullying
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was to listen to, examine and conceptualise students’ perspectives on bullying. Students’ perspectives have not been commonly heard in research and less qualitative research has been conducted. This study contributes with students’ perspectives on bullying using semi-structured interviews with students from fourth-to eighth grade.This thesis includes four studies. The aim with paper I was to investigate how bystander actions in bullying situations and reasons behind these actions were articulated. Paper II was a comparison study between Sweden and US, focused on how students articulate and discuss what factors influence students’ decisions to defend or not defend victims when witnessing bullying. The aim in Paper III was to study how students themselves discuss, reason and make sense of how and why bullying processes emerges in their social worlds. In paper IV the aim was to study how junior high school girls discuss and understand bullying. Findings reveal that students’ reactions as bystanders to bullying depend on how they define the situation. Explanations to the emergence of bullying were understood through a complex social ordering of belonging process. Students position themselves and others in striving to belong, and when defining victims as responsible for bullying. Social norms and negotiation of identities were also discussed among the students. Students discussed how gender and a normative peer structure, where a pressure to fit in, interlinked with how they understood bullying.
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| 21. |
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| 22. |
- Geyer, Holly L., et al.
(författare)
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Associations between gender, disease features and symptom burden in patients with myeloproliferative neoplasms : an analysis by the MPN QOL International Working Group
- 2017
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 102:1, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- The myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis, are distinguished by their debilitating symptom profiles, life-threatening complications and profound impact on quality of life. The role gender plays in the symptomatology of myeloproliferative neoplasms remains under-investigated. In this study we evaluated how gender relates to patients' characteristics, disease complications and overall symptom expression. A total of 2,006 patients (polycythemia vera=711, essential thrombocythemia=830, myelofibrosis=460, unknown=5) were prospectively evaluated, with patients completing the Myeloproliferative Neoplasm-Symptom Assessment Form and Brief Fatigue Inventory Patient Reported Outcome tools. Information on the individual patients' characteristics, disease complications and laboratory data was collected. Consistent with known literature, most female patients were more likely to have essential thrombocythemia (48.6% versus 33.0%; P<0.001) and most male patients were more likely to have polycythemia vera (41.8% versus 30.3%; P<0.001). The rate of thrombocytopenia was higher among males than females (13.9% versus 8.2%; P<0.001) and males also had greater red-blood cell transfusion requirements (7.3% versus 4.9%; P=0.02) with shorter mean disease duration (6.4 versus 7.2 years, P=0.03). Despite there being no statistical differences in risk scores, receipt of most therapies or prior complications (hemorrhage, thrombosis), females had more severe and more frequent symptoms for most individual symptoms, along with overall total symptom score (22.8 versus 20.3; P<0.001). Females had particularly high scores for abdominal-related symptoms (abdominal pain/discomfort) and microvascular symptoms (headache, fatigue, insomnia, concentration difficulties, dizziness; all P<0.01). Despite complaining of more severe symptom burden, females had similar quality of life scores to those of males. The results of this study suggest that gender contributes to the heterogeneity of myeloproliferative neoplasms by influencing phenotypic profiles and symptom expression.
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| 23. |
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| 24. |
- Geyer, Holly, et al.
(författare)
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Symptomatic Profiles of Patients With Polycythemia Vera : Implications of Inadequately Controlled Disease
- 2016
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 34:2, s. 151-
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Polycythemia vera (PV) is a myeloproliferative neoplasm (MPN) associated with disabling symptoms and a heightened risk of life-threatening complications. Recent studies have demonstrated the effectiveness of JAK inhibitor therapy in patients with PV patients who have a history of prior hydroxyurea (HU) use (including resistance or intolerance), phlebotomy requirements, and palpable splenomegaly. We aimed to determine how these features contribute alone and in aggregate to the PV symptom burden.PATIENTS AND METHODS: Through prospective evaluation of 1,334 patients with PV who had characterized symptom burden, we assessed patient demographics, laboratory data, and the presence of splenomegaly by disease feature (ie, known HU use, known phlebotomy requirements, splenomegaly).RESULTS: The presence of each feature in itself is associated with a moderately high symptom burden (MPN symptom assessment form [SAF] total symptom score [TSS] range, 27.7 to 29.2) that persists independent of PV risk category. In addition, symptoms incrementally increase in severity with the addition of other features. Patients with PV who had all three features (PV-HUPS) faced the highest total score (MPN-SAF TSS, 32.5) but had similar individual symptom scores to patients with known HU use (PV-HU), known phlebotomy (PV-P), and splenomegaly (PV-S).CONCLUSION: The results of this study suggest that patients with PV who have any one of the features in question (known HU use, known phlebotomy, or splenomegaly) have significant PV-associated symptoms. Furthermore, it demonstrates that many PV symptoms remain severe independent of the number of features present.
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| 25. |
- Gilbe, Carl, et al.
(författare)
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Predicting slagging tendencies for biomass pellets fired in residential appliances : a comparison of different prediction methods
- 2008
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Ingår i: Energy & Fuels. - Washington : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 22:6, s. 3680-3686
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a comparison between four different types (both empirical and theoretical) of techniques to predict the slagging tendencies in residential pellet combustion appliances was performed. The four techniques used were the standard ash fusion test (SS ISO-540) used in the Swedish pellet standard (SS 18 7120), thermal analysis (TGA/DTA), thermochemical model calculations, and a laboratory-scale sintering test. The tests were performed with 12 pelletized biomass raw materials, and the results were compared with measured slagging tendencies in controlled combustion experiments in a commercial under-fed pellet burner (20 kW) installed in a reference boiler. The results showed significant differences in the prediction of slagging tendencies between different predicting techniques and fuels. The method based on thermal analysis (TGA/DTA) of produced slags must be further developed before useful information could be provided of the slagging behavior of different fuels. The used sintering method must also be further improved before the slagging tendency of fuels forming slags extremely rich in silicon (e.g., some grasses) can be predicted. Relatively good agreement was obtained between results from chemical equilibrium calculations and the actual slagging tendencies from the combustion tests. However, the model calculations must be further improved before quantitative results can be used. The results from the standard ash fusion test (SS ISO 540) showed, in general, relatively high deformation temperatures, therefore predicting a less problematic behavior of the fuels in comparison to the actual slagging tendencies obtained from controlled combustion experiments in commercial pellet burner equipment. Nevertheless, the method predicted, in most cases, the same fuel-specific slagging (qualitatively) trends as the corresponding combustion behavior.
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| 26. |
- Gilbe, Carl, et al.
(författare)
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Slagging characteristics during residential combustion of biomass pellets
- 2008
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 22:5, s. 3536-43
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Tidskriftsartikel (refereegranskat)abstract
- Limited availability of sawdust and planer shavings and an increasing demand for biomass pellets in Europe are pushing the market toward other, more problematic raw materials with broader variation in total fuel ash content and composition of the ash forming elements as well as in their slagging tendencies. The main objective in the present work was therefore to determine the influence of fuel-ash composition on residual ash and slag behavior. Twelve different biomass pellets were used: reed canary grass (two different samples), hemp (two different samples), wheat straw, salix, logging residues (two different samples), stem wood (sawdust) as well as spruce, pine, and birch bark. The different pellet qualities were combusted in a commercial under fed pellet burner (20 kW) installed in a reference boiler. Continuous measurements of O2, CO, CO2, HCl, SO2, and total particle matter mass concentrations were determined in the exhaust gas directly after the boiler. The collected slag deposits, the corresponding deposited bottom ash in the boiler and the collected particle matter were characterized with X-ray diffraction (XRD) and scanning electron microscopy combined with energy dispersive X-ray analysis (SEM/EDS). For biomass fuel pellets rich in silicon (either inherent or contaminated with sand) and low content of alkaline earth metals the main part of the potassium reacted with the silicon rich ash-residual, forming sticky alkali-silicate particles, which were not entrained from the burner and thereby giving rise to/initiating slag formation. Silicon rich fuels, i.e. fuels were the ash characteristics were dominated by silicate-alkali chemistry, therefore generally showed relatively high slagging tendencies. Straw fuels have typically this ash composition but exceptions to these general trends exists (e.g., one of the hemp fuels used in this work). Wood derived fuels with a relatively low inherent silicon content therefore showed low or relatively moderate slagging tendencies. However, contamination of sand material to these fuels may greatly enhance the slagging tendencies.
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| 27. |
- Grigull, Susanne, et al.
(författare)
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Enkätstudie – Insamling och lagring av bergtekniska och hydrogeologiska data
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Insamling av bergtekniska och hydrogeologiska data sker kontinuerligt och i olika faser av bergbyggnadsprojekt. I nuläget är insamlingsprocesserna dock inte standardiserade och det finns inget centralt, nationellt system för att lagra insamlade data. Det är också svårt att värdera eller återanvända data från tidigare projekt och oftast måste all nödvändiga fältdata samlas in från noll inför nya infrastrukturprojekt, även i områden där det finns tidigare bergbyggnation. Arbete inför och under denna förstudie pekar på ett stort behov av dels en tydligare och delvis förbättrad metodik för insamling av data och dels önskemål om en nationell portal för åtkomst till arkiv och databaser, med information från tidigare bergbyggnadsprojekt i ett område.Med hjälp av två enkätstudier som skickades ut till olika aktörer i bergbyggbranschen har vi identifierat geologiska, bergtekniska och hydrogeologiska parametrar vars insamlingsmetodik och metodbeskrivningar är i behov av att förbättras och eventuellt standardiseras. Med hjälp av enkätsvaren har befintliga databaslösningar samt önskemål runt funktionaliteten av en framtida nationell databas också analyserats.Enkätstudien pekar också på att en standardisering av datainsamlingsprocessen är nödvändig för att säkerställa tillförlitligheten och spårbarheten av data, samt på att standardiserad metodik bör vara anpassad till projektkomplexitet och i möjligaste mån ansluta till nuvarande internationellt accepterad metodik. Studien visar dock även att bergbyggbranschens åsikter är mycket splittrade kring vissa frågor. Hur processen att driva utvecklingen och förvaltandet av metodik, metodbeskrivningar och dataportal/databas är inte heller självklart, eller hur detta ska finansieras och vilka förvaltande organ som ska ansvara.Det rekommenderas i denna förstudie att man vid en uppbyggnad av en nationell databas delar upp en sådan i ett sökbart dokumentarkiv och i en parameterdatabas. En eller flera statliga organisationer bör ha huvudansvaret för förvaltning.Föreliggande rapport är tänkt att tjäna som beslutsunderlag vid initiering och finansiering av projekt inom det aktuella området. Det rekommenderas starkt att den eller de organisationerna som ska bygga upp ett dokumentarkiv och en nationell parameterdatabas tar hänsyn till de funktionsönskemål som tas upp i rapporten.Notera att denna rapport även finns tillgänglig i PDF-format på Stiftelsen BergtekniskForskning – BeFos hemsida. Länkarna i rapporten kan enkelt öppnas direkt från PDF-filen och bilder kan förstoras.
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| 28. |
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| 29. |
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| 30. |
- Kaarre, Janina, et al.
(författare)
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ChatGPT can yield valuable responses in the context of orthopaedic trauma surgery
- 2024
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Ingår i: Journal of Experimental Orthopaedics. - : John Wiley & Sons. - 2197-1153. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess the possibility of using Generative Pretrained Transformer (ChatGPT) specifically in the context of orthopaedic trauma surgery by questions posed to ChatGPT and to evaluate responses (correctness, completeness and adaptiveness) by orthopaedic trauma surgeons.Methods: ChatGPT (GPT-4 of 12 May 2023) was asked to address 34 common orthopaedic trauma surgery-related questions and generate responses suited to three target groups: patient, nonorthopaedic medical doctor and expert orthopaedic surgeon. Three orthopaedic trauma surgeons independently assessed ChatGPT's responses by using a three-point response scale with a response range between 0 and 2, where a higher number indicates better performance (correctness, completeness and adaptiveness).Results: A total of 18 (52.9%) of all responses were assessed to be correct (2.0) for the patient target group, while 22 (64.7%) and 24 (70.5%) of the responses were determined to be correct for nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively. Moreover, a total of 18 (52.9%), 25 (73.5%) and 28 (82.4%) of the responses were assessed to be complete (2.0) for patients, nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively. The average adaptiveness was 1.93, 1.95 and 1.97 for patients, nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively.Conclusion: The study results indicate that ChatGPT can yield valuable and overall correct responses in the context of orthopaedic trauma surgery across different target groups, which encompassed patients, nonorthopaedic medical surgeons and expert orthopaedic surgeons. The average correctness scores, completeness levels and adaptiveness values indicated the ability of ChatGPT to generate overall correct and complete responses adapted to the target group.
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| 31. |
- Kaarre, Janina, et al.
(författare)
-
ChatGPT can yield valuable responses in the context of orthopaedic trauma surgery
- 2024
-
Ingår i: Journal of Experimental Orthopaedics. - : John Wiley & Sons. - 2197-1153. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeTo assess the possibility of using Generative Pretrained Transformer (ChatGPT) specifically in the context of orthopaedic trauma surgery by questions posed to ChatGPT and to evaluate responses (correctness, completeness and adaptiveness) by orthopaedic trauma surgeons.MethodsChatGPT (GPT-4 of 12 May 2023) was asked to address 34 common orthopaedic trauma surgery-related questions and generate responses suited to three target groups: patient, nonorthopaedic medical doctor and expert orthopaedic surgeon. Three orthopaedic trauma surgeons independently assessed ChatGPT's responses by using a three-point response scale with a response range between 0 and 2, where a higher number indicates better performance (correctness, completeness and adaptiveness).ResultsA total of 18 (52.9%) of all responses were assessed to be correct (2.0) for the patient target group, while 22 (64.7%) and 24 (70.5%) of the responses were determined to be correct for nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively. Moreover, a total of 18 (52.9%), 25 (73.5%) and 28 (82.4%) of the responses were assessed to be complete (2.0) for patients, nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively. The average adaptiveness was 1.93, 1.95 and 1.97 for patients, nonorthopaedic medical doctors and expert orthopaedic surgeons, respectively.ConclusionThe study results indicate that ChatGPT can yield valuable and overall correct responses in the context of orthopaedic trauma surgery across different target groups, which encompassed patients, nonorthopaedic medical surgeons and expert orthopaedic surgeons. The average correctness scores, completeness levels and adaptiveness values indicated the ability of ChatGPT to generate overall correct and complete responses adapted to the target group.
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| 32. |
- Kaarre, Janina, 1996, et al.
(författare)
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Exploring the potential of ChatGPT as a supplementary tool for providing orthopaedic information
- 2023
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Ingår i: Knee Surgery Sports Traumatology Arthroscopy. - 0942-2056 .- 1433-7347.
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeTo investigate the potential use of large language models (LLMs) in orthopaedics by presenting queries pertinent to anterior cruciate ligament (ACL) surgery to generative pre-trained transformer (ChatGPT, specifically using its GPT-4 model of March 14th 2023). Additionally, this study aimed to evaluate the depth of the LLM's knowledge and investigate its adaptability to different user groups. It was hypothesized that the ChatGPT would be able to adapt to different target groups due to its strong language understanding and processing capabilities.MethodsChatGPT was presented with 20 questions and response was requested for two distinct target audiences: patients and non-orthopaedic medical doctors. Two board-certified orthopaedic sports medicine surgeons and two expert orthopaedic sports medicine surgeons independently evaluated the responses generated by ChatGPT. Mean correctness, completeness, and adaptability to the target audiences (patients and non-orthopaedic medical doctors) were determined. A three-point response scale facilitated nuanced assessment.ResultsChatGPT exhibited fair accuracy, with average correctness scores of 1.69 and 1.66 (on a scale from 0, incorrect, 1, partially correct, to 2, correct) for patients and medical doctors, respectively. Three of the 20 questions (15.0%) were deemed incorrect by any of the four orthopaedic sports medicine surgeon assessors. Moreover, overall completeness was calculated to be 1.51 and 1.64 for patients and medical doctors, respectively, while overall adaptiveness was determined to be 1.75 and 1.73 for patients and doctors, respectively.ConclusionOverall, ChatGPT was successful in generating correct responses in approximately 65% of the cases related to ACL surgery. The findings of this study imply that LLMs offer potential as a supplementary tool for acquiring orthopaedic knowledge. However, although ChatGPT can provide guidance and effectively adapt to diverse target audiences, it cannot supplant the expertise of orthopaedic sports medicine surgeons in diagnostic and treatment planning endeavours due to its limited understanding of orthopaedic domains and its potential for erroneous responses.
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| 33. |
- Kock, Peder, et al.
(författare)
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A deviation display method for visualising data in mobile gamma-ray spectrometry.
- 2010
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043. ; 68, s. 1832-1838
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Tidskriftsartikel (refereegranskat)abstract
- A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded (137)Cs and (241)Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The deviation display enhances positive significant changes while suppressing the natural background fluctuations. After an initialisation time of about 10min this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the deviation display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems.
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| 34. |
- Larsson, Sylvia, et al.
(författare)
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Cassava Stem Powder as an Additive in Biomass Fuel Pellet Production
- 2015
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Ingår i: Energy and Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 29, s. 5902-5908
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Tidskriftsartikel (refereegranskat)abstract
- In biomass fuel pelletizing, some raw materials with less favorable binding properties require a binding enhancing additive for enhancing required pellet quality. Starch is commonly used as a binder in industrial fuel pelletizing but is a refined product that adds substantially to pellet production costs. In this study, finely milled cassava stems, a starch-rich, cheap, and underutilized byproduct from food production, were used and compared to refined starch as an additive in biofuel pellet production. The evaluation was performed in an experimental design with the factors cassava stem/starch content, moisture content, and material temperature. Measured responses were pellet bulk density, mechanical durability, amount of fines, pelletizer motor current, coefficient of variance for pelletizer motor current, CVA (a measure of process stability), pellet temperature, die temperature, and pellet moisture. Each response was modeled by multiple linear regression (MLR). Cassava stem addition gave similar effects as starch addition by increasing pellet durability and reducing the amount of fines, particularly at low moisture contents (MC ∼ 11%). The highest pellet durability in the study was achieved at a low moisture content (11% MC) when using cassava stem as an additive. Combustion properties of the pellets were determined in a residential pellet burner. Low emissions and no ash fouling were obtained for both of the additive types. In conclusion, cassava stem powder is a good additive substitute for refined starch to increase fuel pellet quality.
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| 35. |
- Larsson, Sylvia, et al.
(författare)
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Deformation and breakage of biofuel wood pellets
- 2020
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Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762 .- 1744-3563. ; 153, s. 419-426
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Tidskriftsartikel (refereegranskat)abstract
- A convenient approach to employ an elliptic load-deformation elastoplastic approximation has been proposed and used to evaluate the mechanical behavior of pinewood biofuel pellets from lab-scale compressive load-deformation measurements. Verification of model predictions has been attempted against apparent finite element method based simulations. A database of essential mechanical properties has been established. This submission is intended as a model for being able to study the deformation and breakage behavior using lab-scale compression tests. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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| 36. |
- Larsson, Sylvia, et al.
(författare)
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Effects of moisture content, torrefaction temperature, and die temperature in pilot scale pelletizing of torrefied Norway spruce
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 102, s. 827-832
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Tidskriftsartikel (refereegranskat)abstract
- Pilot scale pelletizing of torrefied Norway spruce was performed in a factorial design with controlled factors at two levels: material moisture content (11% and 15%) and torrefaction temperature (270 and 300 °C), and die temperature as an uncontrolled factor (60–105 °C). Compared to commercial wood pellets, produced pellets had comparable bulk densities (630–710 kg/m3) but lower pellet durability (80–90%). Energy consumption for pelletizing of torrefied materials was approximately 100% higher than for softwood pelletizing, despite using a much shorter die channel length (35 vs. 55 mm:s), and the amounts of fines were high (10–30%). Die temperature showed a strong positive correlation with pellet production rate. Material moisture content had little influence on pellet quality and production rate, but addition of water created handling problems due to bad flow behavior.
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| 37. |
- Larsson, Sylvia, et al.
(författare)
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Fuel pellets from lodge pole pine first thinnings
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Stemwood and whole trees of lodgepole pine (Pinus contorta Dougl. var. latifolia L.) were evaluated asraw materials for fuel pellets in a pilot scale pelletizing study. Pellet and pelletizing properties were measured andmodeled in an experimental design where raw material moisture content (%), die channel length (mm), and storage time(days) were varied. Additionally, ash contents (%), extractive contents (%), and ash melting temperatures (°C) wereanalyzed. For both assortments, raw material moisture content was positively correlated to pellet bulk density anddurability (range 9-13%, wet base). Both assortments had ash contents below 0.7%, and thus, fulfilled the demands forclass A1 pellets.
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| 38. |
- Larsson, Sylvia, et al.
(författare)
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Prediction of ISO 17831-1:2015 mechanical biofuel pellet durability from single pellet characterization
- 2017
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 163, s. 8-15
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Tidskriftsartikel (refereegranskat)abstract
- In fuel pellet research, single pellet production methods are frequently used for model building in order to predict how raw material characteristics, formulas, and process settings affect product quality and the industrial process performance. For relevance, it is critical that bench-scale research results are correctly interpreted when transferred from the model system to the industrial application. In this study, the validity of different practically applicable single pellet' durability/compressive strength methods as predictors for ISO 17831-1: 2015 standard fuel pellet durability was determined. To ensure correct interpretation a set of wood pellet samples with negligible relationship between durability and bulk density was used for calibration. Mean values from 20 replicate single pellet measurements on 12 assortments with pellet durability > 90% was linearly correlated with the ISO standard durability with R-2 = 0.83 (ISO tumbler) and 0.94 (Ligno tester). Compressive strength could be modelled (R-2:0.89 and Q(2):0.82) from pellet density and Ligno single pellet durability, concluding that compressive strength is equally affected by each of these two parameters, and thus, compressive strength cannot be considered as a reliable measure for ISO 17831-1: 2015 standard fuel pellet durability. (C) 2017 Elsevier B.V. All rights reserved.
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| 39. |
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| 40. |
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| 41. |
- Lestander, Torbjörn, et al.
(författare)
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Prediction of Resin and Fatty Acid Content of Biorefinery Feedstock by On-line Near-Infrared (NIR) Spectroscopy
- 2010
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Ingår i: Energy and Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 24, s. 5148-5152
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Tidskriftsartikel (refereegranskat)abstract
- Extractives in biorefinery feedstock are a source of precursor chemicals and biofuel products. Resin and fatty acids (RFAs) in such extractives constitute an interesting fraction, which may contain both chemically attractive precursors and also problematic volatile organic compounds. On-line near-infrared (NIR) spectra were collected from a process stream, designed experimentally and involving softwood lignocelluloses; the data were regressed using partial least-squares to give RFA concentrations that varied between 0.1 and 0.5% (dry weight basis). At-line NI R models were also constructed using spectral data from pelletized samples from the process stream. In addition, off-line NIR modeling was conducted using softwoods with a wider R FA variation range (0.1-1.0% dry weight basis). All of the calibration models obtained exhibited good predictive abilities. The laboratory-based off-line NIR model explained 94.5% of the variation in concentrations and had a prediction error of 0.070% for the RFA content. The coefficient of variation (CV), representing the percentage of the ratio between the prediction error and the average concentration, was 17.8%. The on-line and at-line models explained 71.3-79.6% of the variation in the RFA concentrations and had prediction errors within the range of 0.026-0.041% and CVs of 13.7-18.1%. This was excellent in comparison to the ca. 10% error in accuracy when determining the RFA reference values. The results illustrate that on-line NI R spectroscopy provides a valid method for real-time predictions of RFA concentrations in biomaterials. This should facilitate better monitoring and process control as well as targeted pretreatments to obtain tailor-made biorefinery feedstock, thus adding value to the production process.
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| 42. |
- Lindvall, Eva, et al.
(författare)
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Ash as a phosphorus fertilizer to reed canary grass: effects of nutrient and heavy metal composition on plant and soil
- 2015
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Ingår i: GCB Bioenergy. - : Wiley. - 1757-1693 .- 1757-1707. ; 7, s. 553-564
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Tidskriftsartikel (refereegranskat)abstract
- Fertilization effects and risks of heavy metal enrichment were studied in a field experiment, in which plots of reed canary grass (RCG) were treated annually with three different fertilizers: Ash from co-combustion of RCG and municipal wastes (mixed ash), pure RCG ash, and commercial fertilizer (control). RCG ash is a waste product that is currently expensive to dispose of. The amounts of nutrients applied annually were 100kgha(-1)N, 15kgha(-1) P, and 80kgha(-1)K in all treatments. In the ash treatments, all P derived from ash, whereas N and part of the K were supplemented by fertilizers. The amount of heavy metals exceeded the limits set by the Swedish Environmental Protection Agency for all elements analyzed in the mixed ash and for Ni and Cr in the RCG ash. There were no significant differences between treatments in terms of RCG dry matter yield obtained at harvest in spring, or in heavy metal concentrations in the biomass. Soil samples from 0-5cm, 5-10cm, and 10-20cm below the surface showed significant differences between treatments for the concentration of Cd, Cr, Cu, Pb, and Zn, with higher concentrations in plots fertilized with mixed ash than in the control. Neither spring yield nor soil available P was reduced by using ash instead of mineral P fertilizer, suggesting that pure RCG ash can be used to complement commercial fertilizer, albeit less frequently than here. However, ash derived from co-combusting RCG with different waste materials (mixed ash treatment) should not be used in RCG production due to the high heavy metal content.
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- Ludvigsson, Johnny, et al.
(författare)
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GAD65 antigen therapy in recently diagnosed type 1 diabetes mellitus
- 2012
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 366:5, s. 433-442
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The 65-kD isoform of glutamic acid decarboxylase (GAD65) is a major autoantigen in type 1 diabetes. We hypothesized that alum-formulated GAD65 (GAD-alum) can preserve beta-cell function in patients with recent-onset type 1 diabetes.METHODS: We studied 334 patients, 10 to 20 years of age, with type 1 diabetes, fasting C-peptide levels of more than 0.3 ng per milliliter (0.1 nmol per liter), and detectable serum GAD65 autoantibodies. Within 3 months after diagnosis, patients were randomly assigned to receive one of three study treatments: four doses of GAD-alum, two doses of GAD-alum followed by two doses of placebo, or four doses of placebo. The primary outcome was the change in the stimulated serum C-peptide level (after a mixed-meal tolerance test) between the baseline visit and the 15-month visit. Secondary outcomes included the glycated hemoglobin level, mean daily insulin dose, rate of hypoglycemia, and fasting and maximum stimulated C-peptide levels.RESULTS: The stimulated C-peptide level declined to a similar degree in all study groups, and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group (P=0.10). The use of GAD-alum as compared with placebo did not affect the insulin dose, glycated hemoglobin level, or hypoglycemia rate. Adverse events were infrequent and mild in the three groups, with no significant differences.CONCLUSIONS: Treatment with GAD-alum did not significantly reduce the loss of stimulated C peptide or improve clinical outcomes over a 15-month period.
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Lärares etik och professionella arbete : skolan som moralisk praktik : en vänbok till Gunnel Colnerud
- 2013
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Gunnel Colnerud, professor vid Institutionen för beteendevetenskap och lärande, vid Linköpings universitet har under den största delen av sitt yrkesverksamma liv varit engagerad i skolfrågor av olika slag. Ofta har fokus för hennes intresse och uppdrag legat i att förstå skolans vardagsliv och det komplexa uppdrag som läraryrket innebär. Gunnel fyller 67 år i januari 2015 och denna vänbok är en hyllning till henne från kollegor, både nationellt och internationellt, samt tidigare doktorander. Bidragen i antologin, Lärares etik och professionella arbete - skolan som moralisk praktik, är tänkt att spegla de områden som Gunnel i sin forskning varit engagerad i.Innan Gunnel påbörjade sin forskarutbildning i pedagogik var hon verksam som psykolog inom skolhälsovården. Denna erfarenhet av att ha mött barn och elevers utsatthet samt lärares ständiga arbete med att möta olika typer av förändringar och hantera en komplex yrkesroll är något som Gunnel burit med sig in i sin forskning, vilket inte minst syns i hennes outtröttliga engagemang i att vara en forskare som bidrar till skolans praktik.I mitten av nittiotalet Jade Gunnel fram sin avhandling som byggde på intervjuer med yrkesverksamma lärare och handlade om etiska dilemman lärare ställs inför i sitt yrkesutövande. Gunnel har allt sedan avhandlingsarbetet varit mycket engagerad i etiska frågor i relation till läraruppdraget och var en av de pådrivande krafterna i att tillsammans med Sveriges båda lärarförbund formulera gemensamma yrkesetiska principer, som kom att benämnas Lärares yrkesetik. I detta arbete gjorde Gunnel betydande insatser genom att problematisera yrkesetik som fenomen, medverka i otaliga utbildningsinsatser för lärare och lärarstudenter inom området och sist men inte minst bidra till att etablera yrkesetik som forskningsfält.Ett kännetecknande drag för Gunnels forskning har varit den starka viljan och övertygelsen om att forskning om skola behöver ske i relation till och med skolans praktik. Tillsammans med sin make och kollega professor Kjell Granström etablerade Gunnel en forskarmiljö med fokus på praxisnära forskning. Vi som är redaktörer för denna vänbok har alla haft förmånen att vara doktorander till Gunnel eller Kjell och fått möjlighet att växa som forskare i en forskarmiljö som präglats av kreativitet, engagemang och spännande diskussioner.Norrköping och Linköping, oktober 2013Helene, Karin, Marcus & Robert
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