| 1. |
- Golemis, Aris, et al.
(författare)
-
KvarkenSat: mission concept and technical overview of a 2U Swedish - Finnish CubeSat
- 2021
-
Ingår i: IAC 2021 Congress Proceedings, 72<sup>nd</sup> International Astronautical Congress (IAC), Dubai, United Arab Emirates. - : International Astronautical Federation (IAF).
-
Konferensbidrag (refereegranskat)abstract
- Kvarken Space Centre is a project conducted by a consortium of Finnish and Swedish academic institutions aiming to enhance the economic activities of the Kvarken region shared by the two countries, by improving the regional competence in space technology. In this framework, the consortium is developing a first 2UCubeSat, namely KvarkenSat, with the goal of exhibiting the regional capabilities in satellite developmentvia performing science and in-orbit demonstration of Finnish payloads. Since the main areas of interestare forestry and sea transportation, the CubeSat will integrate a multispectral camera for forest health and seawater quality analysis and an automatic identification system (AIS) receiver for sea vessel tracking. In addition, the spacecraft will perform the in-orbit demonstration of a miniature water-based resistojet thruster system. KvarkenSat’s last payload will comprise a GNSS receiver that will extract raw data inorder to conduct precise point positioning (PPP) algorithm research. This work is meant to present the mission concept, objectives and technical overview of the current design. The launch of KvarkenSat is planned for Q4 2022 from northern Sweden.
|
|
| 2. |
|
|
| 3. |
- Abou-Hachem, Maher, et al.
(författare)
-
Calcium binding and thermostability of carbohydrate binding module CBM4-2 of Xyn10A from Rhodothermus marinus.
- 2002
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 41:18, s. 5720-5729
-
Tidskriftsartikel (refereegranskat)abstract
- Calcium binding to carbohydrate binding module CBM4-2 of xylanase 10A (Xyn10A) from Rhodothermus marinus was explored using calorimetry, NMR, fluorescence, and absorbance spectroscopy. CBM4-2 binds two calcium ions, one with moderate affinity and one with extremely high affinity. The moderate-affinity site has an association constant of (1.3 +/- 0.3) x 10(5) M(-1) and a binding enthalpy DeltaH(a) of -9.3 +/- 0.4 kJ x mol(-1), while the high-affinity site has an association constant of approximately 10(10) M(-1) and a binding enthalpy DeltaH(a) of -40.5 +/- 0.5 kJ x mol(-1). The locations of the binding sites have been identified by NMR and structural homology, and were verified by site-directed mutagenesis. The high-affinity site consists of the side chains of E11 and D160 and backbone carbonyls of E52 and K55, while the moderate-affinity site comprises the side chain of D29 and backbone carbonyls of L21, A22, V25, and W28. The high-affinity site is in a position analogous to the calcium site in CBM4 structures and in a recent CBM22 structure. Binding of calcium increases the unfolding temperature of the protein (T(m)) by approximately 23 degrees C at pH 7.5. No correlation between binding affinity and T(m) change was noted, as each of the two calcium ions contributes almost equally to the increase in unfolding temperature.
|
|
| 4. |
- Abou Hachem, Maher, et al.
(författare)
-
Carbohydrate-binding modules from a thermostable Rhodothermus marinus xylanase : Cloning, expression and binding studies
- 2000
-
Ingår i: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021. ; 345:1, s. 53-60
-
Tidskriftsartikel (refereegranskat)abstract
- The two N-terminally repeated carbohydrate-binding modules (CBM4-1 and CBM4-2) encoded by xyn10A from Rhodothermus marinus were produced in Escherichia coli and purified by affinity chromatography. Binding assays to insoluble polysaccharides showed binding to insoluble xylan and to phosphoric-acid-swollen cellulose but not to Avicel or crystalline cellulose. Binding to insoluble substrates was significantly enhanced by the presence of Na+ and Ca2+ ions. The binding affinities for soluble polysaccharides were tested by affinity electrophoresis; strong binding occurred with different xylans and β-glucan. CBM4-2 displayed a somewhat higher binding affinity than CBM4-1 for both soluble and insoluble substrates but both had similar specificities. Binding to short oligosaccharides was measured by NMR; both modules bound with similar affinities. The binding of the modules was shown to be dominated by enthalpic forces. The binding modules did not contribute with any significant synergistic effects on xylan hydrolysis when incubated with a Xyn10A catalytic module. This is the first report of family 4 CBMs with affinity for both insoluble xylan and amorphous cellulose.
|
|
| 5. |
- Abou-Hachem, Maher, et al.
(författare)
-
The modular organisation and stability of a thermostable family 10 xylanase
- 2003
-
Ingår i: Biocatalysis and Biotransformation. - : Informa UK Limited. - 1024-2422 .- 1029-2446. ; 21:5-6, s. 253-260
-
Tidskriftsartikel (refereegranskat)abstract
- The thermophilic marine bacterium Rhodothermus marinus produces a modular family 10 xylanase (Xyn10A). It consists of two N-terminal family 4 carbohydrate binding modules (CBMs) followed by a domain of unknown function (D3), and a catalytic module (CM) flanked by a small fifth domain (D5) at its C-terminus. Several truncated mutants of the enzyme have been produced and characterised with respect to biochemical properties and stability. Multiple calcium binding sites are shown to be present in the two N-terminal CBMs and recent evidence suggests that the third domain of the enzyme also has the ability to bind the same metal ligand. The specific binding of Ca2+ was demonstrated to have a pronounced effect on thermostability as shown by differential scanning calorimetry and thermal inactivation studies. Furthermore, deletion mutants of the enzyme were less stable than the full-length enzyme suggesting that module interactions contributed to the stability of the enzyme. Finally, recent evidence indicates that the fifth domain of Xyn10A is a novel type of module mediating cell-attachment.
|
|
| 6. |
- Ahlgren, S., et al.
(författare)
-
Ammonium nitrate fertiliser production based on biomass : Environmental effects from a life cycle perspective
- 2008
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 99:17, s. 8034-8041
-
Tidskriftsartikel (refereegranskat)abstract
- Ammonium nitrate and calcium ammonium nitrate are the most commonly used straight nitrogen fertilisers in Europe, accounting for 43% of the total nitrogen used for fertilisers. They are both produced in a similar way; carbonate can be added as a last step to produce calcium ammonium nitrate. The environmental impact, fossil energy input and land use from using gasified biomass (cereal straw and short rotation willow (Salix) coppice) as feedstock in ammonium nitrate production were studied in a cradle-to-gate evaluation using life cycle assessment methodology. The global warming potential in the biomass systems was only 22-30% of the impact from conventional production using natural gas. The eutrophication potential was higher for the biomass systems due to nutrient leaching during cultivation, while the acidification was about the same in all systems. The primary fossil energy use was calculated to be 1.45 and 1.37 MJ/kg nitrogen for Salix and straw, respectively, compared to 35.14 MJ for natural gas. The biomass production was assumed to be self-supporting with nutrients by returning part of the ammonium nitrate produced together with the ash from the gasification. For the production of nitrogen from Salix, it was calculated that 3914 kg of nitrogen can be produced every year from 1 ha, after that 1.6% of the produced nitrogen has been returned to the Salix production. From wheat straw, 1615 kg of nitrogen can be produced annually from 1 ha, after that 0.6% of the nitrogen has been returned. © 2008 Elsevier Ltd. All rights reserved.
|
|
| 7. |
|
|
| 8. |
- Ahlgren, S., et al.
(författare)
-
Future fuel supply systems for organic production based on Fischer-Tropsch diesel and dimethyl ether from on-farm-grown biomass
- 2008
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 99:1, s. 145-155
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of making a 1000 ha organic farm self-sufficient in renewable fuel were studied. Biomass grown on-farm can be transported to large fuel production facilities and the fuel transported back to the farm. Two fuels, Fischer-Tropsch diesel (FTD) and dimethyl ether (DME), produced from either straw or short-rotation willow coppice (Salix), were studied. The environmental impact, land use and energy balance were calculated using life-cycle methodology. It was calculated that the straw-based systems had only 32-39% of the impact on global warming (kg [CO2-eq]) compared to the Salix-based systems. For acidification and eutrophication, the differences between the systems were less significant. The energy balances were 8.9 and 9.6 for FTD and 10.1 and 10.0 for DME, from straw and Salix, respectively. To become self-sufficient in FTD, 108 ha has to be set aside for Salix production or 261 ha of straw collected from the existing crop rotation. For DME the corresponding figures are 38 and 70 ha. The many by-products in the FTD scenarios explain the large difference between fuels. Comparing FTD and DME, the differences in environmental impact were small. Considering this, FTD is a more likely alternative since DME requires a pressurised infrastructure system and engine modifications. © 2007 IAgrE.
|
|
| 9. |
- Ahlgren, Serina, et al.
(författare)
-
Tractive power in organic farming based on fuel cell technology : Energy balance and environmental load
- 2009
-
Ingår i: Agricultural Systems. - : Elsevier BV. - 0308-521X .- 1873-2267. ; 102:1-3, s. 67-76
-
Tidskriftsartikel (refereegranskat)abstract
- This study analysed a future hypothetical organic farm self-sufficient in renewable tractor fuel. Biomass from the farm was assumed to be transported to a central fuel production plant and the fuel returned to the farm, where it was utilised in fuel cell powered tractors. The land use, energy balance and environmental impact of five different scenarios were studied. In the first two scenarios, straw was used as raw material for production of hydrogen or methanol via thermochemical gasification. In the third and fourth scenarios, short rotation forest (Salix) was used as raw material for the same fuels. In the fifth scenario, ley was used as raw material for hydrogen fuel via biogas production. The straw scenarios had the lowest impact in all studied environmental impact categories since the Salix scenarios had higher soil emissions and the ley scenario had comparatively large emissions from the fuel production. The energy balance was also favourable for straw, 16.3 and 19.5 for hydrogen and methanol respectively, compared to Salix 14.2 and 15.6. For ley to hydrogen the energy balance was only 6.1 due to low efficiency in the fuel production. In the Salix scenarios, 1.6% and 2.0% of the land was set aside for raw material production in the hydrogen and methanol scenarios respectively. In the straw scenarios no land needed to be reserved, but straw was collected on 4.3% and 5.3% of the area for hydrogen and methanol respectively. To produce hydrogen from ley, 4% of the land was harvested. The study showed that the difference in environmental performance lay in choice of raw material rather than choice of fuel. Hydrogen is a gas with low volumetric energy density, which requires an adapted infrastructure and tractors equipped with gas tanks. This leads to the conclusion that methanol probably will be the preferred choice if a fuel cell powered farm would be put into practice in the future. © 2009 Elsevier Ltd. All rights reserved.
|
|
| 10. |
|
|
