| 11. |
- Chernov, S. V., et al.
(författare)
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Sr2GaScO5, Sr10Ga6Sc4O25, and SrGa0,75Sc0,25O2,5: a Play in the Octahedra to Tetrahedra Ratio in Oxygen-Deficient Perovskites
- 2012
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 51:2, s. 1094-1103
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Tidskriftsartikel (refereegranskat)abstract
- Three different perovskite-related phases were isolated in the SrGa(1-x)Sc(x)O(2.5) system: Sr(2)GaScO(5), Sr(10)Ga(6)Sc(4)O(25), and SrGa(0.75)Sc(0.25)O(2.5), Sr(2)GaScO(5) (x = 0.5) crystallizes in a brownrnillerite-type structure [space group (S.G.) Icmm, a = 5.91048(5) angstrom, b = 15.1594(1) angstrom, and c = 5.70926(4) angstrom] with complete ordering of Sc(3+) and Ga(3+) over octahedral and tetrahedral positions, respectively. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) (x = 0.4) was determined by the Monte Carlo method and refined using a combination of X-ray, neutron, and electron diffraction data [S.G. I4(1)/a, a = 17.517(1) angstrom, c = 32.830(3) angstrom]. It represents a novel type of ordering of the B cations and oxygen vacancies in perovskites. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) can be described as a stacking of eight perovskite layers along the c axis ...[-(Sc/Ga)O(1.6)-SrO(0.8)-(Sc/Ga)O(1.8)-SrO(0.8)-](2 center dot center dot center dot) Similar to Sr(2)GaScO(5), this structure features a complete ordering of the Sc(3+) and Ga(3+) cations over octahedral and tetrahedral positions, respectively, within each layer. A specific feature of the crystal structure of Sr(10)Ga(6)Sc(4)O(25) is that one-third of the tetrahedra have one vertex not connected with other Sc/Ga cations. Further partial replacement of Sc(3+) by Ga(3+) leads to the formation of the cubic perovskite phase SrGa(0.75)Sc(0.25)O(2.5) (x = 0.25) with a = 3.9817(4) angstrom. This compound incorporates water molecules in the structure forming SrGa(0.75)Sc(0.25)O(2.5)center dot xH(2)O hydrate, which exhibits a proton conductivity of similar to 2.0 x 10(-6) S/cm at 673 K.
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| 12. |
- Gaur, Sarthak, et al.
(författare)
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Catalytic Activity of Titania-Supported Core-Shell Fe3O4@Au NanoCatalysts for CO Oxidation
- 2012
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 116:42, s. 22319-22326
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Tidskriftsartikel (refereegranskat)abstract
- In continuation of our previous work (J. Phys. Chem. Lett. 2010, 1(20), 3141 and J. Phys. Chem. C 2010, 114 (45), 19194), Fe3O4@Au core-shell types of nanoparticles were prepared by coating superparamagnetic iron oxide nanoparticles (SPIONS; similar to 4.9 nm) with a thin layer of gold (similar to 0.5 nm) and supported on microporous TiO2. To remove the ligands attached to nanoparticles, the catalyst was treated at 200, 300, 400, and 500 degrees C in either (a) a reducing atmosphere with H-2/Ar or (b) an oxidizing atmosphere with O-2/He. The synthesized nanoparticles and freshly prepared catalysts were characterized by HRTEM, which revealed that the size of the Fe3O4@Au nanoparticles was 5.34 +/- 0.71 nm and that of Fe3O4@Au/TiO2 was 5.96 +/- 0.71 nm. Fresh and pretreated programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. To test the activity of Fe3O4@Au/TiO2 catalysts, CO oxidation was performed over catalysts from 30 to 500 degrees C. Results showed that the catalyst treated with H-2/Ar at 500 degrees C had a lower light-off temperature and the highest CO conversion (similar to 68%) at 300 degrees C; however, such a treatment also resulted in catalyst sintering, leading to a net increase in particle size to 7.87 +/- 1.59 nm. The higher catalytic activity of the catalyst treated with H-2 at 500 degrees C can be attributed to the copresence of Fe-0 and Au-0 in the catalyst, the complete removal of organic ligands from the catalyst surface, and possibly the synergistic interaction between Au and Fe.
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| 13. |
- Holleboom, Adriaan G, et al.
(författare)
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Heterozygosity for a Loss-of-Function Mutation in GALNT2 Improves Plasma Triglyceride Clearance in Man
- 2011
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Ingår i: Cell Metabolism. - : Elsevier. - 1550-4131 .- 1932-7420. ; 14:6, s. 811-8
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have identified GALNT2 as a candidate gene in lipid metabolism, but it is not known how the encoded enzyme ppGalNAc-T2, which contributes to the initiation of mucin-type O-linked glycosylation, mediates this effect. In two probands with elevated plasma high-density lipoprotein cholesterol and reduced triglycerides, we identified a mutation in GALNT2. It is shown that carriers have improved postprandial triglyceride clearance, which is likely attributable to attenuated glycosylation of apolipoprotein (apo) C-III, as observed in their plasma. This protein inhibits lipoprotein lipase (LPL), which hydrolyses plasma triglycerides. We show that an apoC-III-based peptide is a substrate for ppGalNAc-T2 while its glycosylation by the mutant enzyme is impaired. In addition, neuraminidase treatment of apoC-III which removes the sialic acids from its glycan chain decreases its potential to inhibit LPL. Combined, these data suggest that ppGalNAc-T2 can affect lipid metabolism through apoC-III glycosylation, thereby establishing GALNT2 as a lipid-modifying gene.
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| 14. |
- Hossain, Mohammad, et al.
(författare)
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Strategic approach for up-scaling safe water access considering hydrogeological suitability and social mapping in Matlab, southeastern Bangladesh
- 2013
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Konferensbidrag (refereegranskat)abstract
- In recent years, there has been a significant progress in understanding the source and mobilization process, sediment-water interactions, and distributions of arsenic in groundwater environment in Bangladesh. However, the impacts of arsenic mitigation are still very limited. A social survey conducted during 2009-2011 in 96 villages in Matlab revealed that only 18% of total tubewells provide As-safe water. The safe water access also varied between 0 and 90 percent in the region due to lack of knowledge about the local geology and unplanned tubewell development. SASMIT, an initiative of KTH-International Groundwater Arsenic Research Group has developed a method for safe tubewell installation considering hydrogeological suitability, safe water access and other relevant social and demographic information into account.Piezometers installed at 15 locations over an area of 410 km2, using local boring techniques allowed to delineate the hydrostratigraphy, characterize the aquifers in terms of sediment characteristics, water chemistry and hydraulic head distribution, which ultimately led to the identification of the suitable aquifers for tapping safe water. The piezometer locations with safe drinking water quality were then targeted for safe well installation based on the determination of safe buffer distances in a cluster of a few villages (mouzas). Social mapping of all the villages within the mauzas were done using GIS to evaluate the availability of safe water options for a cluster of households (bari). For safe well installations, priority was given to regions with safe water access, greater number of beneficiaries especially in poor households, and easy access to the site from a cluster of households. Through this approach, it was thus possible to make 95% of the newly installed wells As-safe thus scaled up the safe water access upto 40% in some mauzas. Thus the as a strategy to improve safe water access, the SASMIT study recommends investigating the hydrogeological suitability through installation of few piezometers with a minimum effort and based on the results the implementation plan can be made using GIS based social mappings for relatively uniform distribution and to maximize the safe water access.
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| 15. |
- Jafari, V., et al.
(författare)
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Construction and demolition lignocellulosic wastes to bioethanol
- 2011
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:11, s. 2771-2775
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Tidskriftsartikel (refereegranskat)abstract
- This work deals with conversion of four construction and demolition (C&D) lignocellulosic wastes including OSB, chipboard, plywood, and wallpaper to ethanol by separate enzymatic hydrolysis and fermentation (SHF). Similar to other lignocelluloses, the wastes were resistant to the enzymatic hydrolysis, in which only up to 7% of their cellulose was hydrolyzed. Therefore, the lignocellulosic wastes were treated with phosphoric acid, sodium hydroxide, or N-methylmorpholine-N-oxide (NMMO), which resulted in improving the subsequent enzymatic hydrolysis to 38.2-94.6% of the theoretical yield. The best performance was obtained after pretreatment by concentrated phosphoric acid, followed by NMMO. The pretreated and hydrolyzed C&D wastes were then successfully fermented by baker's yeast to ethanol with 70.5-84.2% of the theoretical yields. The results indicate the possibility of producing 160 ml ethanol from each kg of the C&D wastes at the best conditions.
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| 16. |
- Jafri, Syed Mohammad Asad Hassan, et al.
(författare)
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Design of a fault-tolerant coarse-grained reconfigurable architecture : A case study
- 2010
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Ingår i: Proceedings of the 11th International Symposium on Quality Electronic Design, ISQED 2010. - 9781424464555 ; , s. 845-852
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Konferensbidrag (refereegranskat)abstract
- This paper considers the possibility of implementing low-cost hardware techniques which would allow to tolerate temporary faults in the datapaths of coarse-grained reconfigurable architectures (CGRAs). Our goal was to use less hardware overhead than commonly used duplication or triplication methods. The proposed technique relies on concurrent error detection by using residue code modulo 3 and re-execution of the last operation, once an error is detected. We have chosen the DART architecture as a vehicle to study the efficiency of this approach to protect its datapaths. Simulation results have confirmed hardware savings of the proposed approach over duplication.
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| 17. |
- Jafri, Syed Mohammad Asad Hassan, et al.
(författare)
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Design of the coarse-grained reconfigurable architecture DART with on-line error detection
- 2014
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Ingår i: Microprocessors and microsystems. - : Elsevier BV. - 0141-9331 .- 1872-9436. ; 38:2, s. 124-136
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the implementation of the coarse-grained reconfigurable architecture (CGRA) DART with on-line error detection intended for increasing fault-tolerance. Most parts of the data paths and of the local memory of DART are protected using residue code modulo 3, whereas only the logic unit is protected using duplication with comparison. These low-cost hardware techniques would allow to tolerate temporary faults (including so called soft errors caused by radiation), provided that some technique based on re-execution of the last operation is used. Synthesis results obtained for a 90 nm CMOS technology have confirmed significant hardware and power consumption savings of the proposed approach over commonly used duplication with comparison. Introducing one extra pipeline stage in the self-checking version of the basic arithmetic blocks has allowed to significantly reduce the delay overhead compared to our previous design.
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| 18. |
- Youngsukkasem, S., et al.
(författare)
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Biogas production by encapsulated methaneproducing bacteria
- 2012
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Ingår i: BioResources. - 1930-2126. ; 7:1, s. 56-65
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Tidskriftsartikel (refereegranskat)abstract
- Encapsulation of methane-producing bacteria was carried out with the objective of enhancing the rate of biogas production. Encapsulation with a one-step liquid-droplet-forming technique was employed for the natural membrane, resulting in spherical capsules with an average diameter and a membrane thickness of 4.3 and 0.2 mm, respectively. The capsules were made from alginate, using chitosan or Ca 2+ as counter-ions, together with the addition of carboxymethylcellulose (CMC). A Durapore® membrane (hydrophilic PVDF) with a pore size of 0.1 μm was used for synthetic encapsulating sachets having width and length dimensions 3×3 and 3×6 cm 2 for holding the bacteria. During the digesting process, the dissolved substrates penetrated through the capsule membrane, and biogas inside the capsules was able to escape by diffusion. The results indicate encapsulation to be a promising method of digestion, with a high density of anaerobic bacteria. The method holds considerable potential for further development of membranes and their applications.
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| 19. |
- Al-Ansari, Nadhir, et al.
(författare)
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Climate change and future long term trends of rainfall at north-east Part of Iraq
- 2014
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Ingår i: Journal of Civil Engineering and Architecture. - : David Publishing Company. - 1934-7359 .- 1934-7367. ; 8:6, s. 790-805
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Tidskriftsartikel (refereegranskat)abstract
- Iraq is facing water shortage problem despite the presence of the Tigris and Euphrates Rivers. In this research, long rainfall trends up to the year 2099 were studied in Sulaimani city northeast Iraq to give an idea about future prospects. Two emission scenarios used by the Intergovernmental Panel on Climate Change (A2 & B2) were employed. The results indicates that the average annual rainfall show a significant downward trend for both A2 and B2 scenarios. In addition, winter projects some increase/decrease in the daily rainfall statistics of wet days, the spring season show very slight drop and no change for both scenarios. However both summer and autumn show a significant reduction in maximum rainfall value especially in 2080s while the other statistics remain nearly the same. The extremes events are to decrease slightly in 2080s with highest decrease associated with A2 scenario. This because the rainfall under scenario A2 is more significant than under scenario B2 and temperature can be very hot and worse with increase in emission scenario which causes the moist air to be evaporated before going up and cause the rainfall. The return period of a certain rainfall will increase in the future when a present storm of 20 year could occur once every 43 year in the 2080s. An increase in the frequency of extreme rainfall depends on the return period, season of the year, the future period considered and the emission scenario under which it will occur
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| 20. |
- Alanbari, Mohammad A., et al.
(författare)
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Application of Simapro7 on Karbala Wastewater Treatment Plant, Iraq
- 2014
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scienpress Ltd. - 1792-9040 .- 1792-9660. ; 4:2, s. 55-68
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Tidskriftsartikel (refereegranskat)abstract
- The use of treated wastewater is becoming more popular especially in countries suffering from water shortages despite the fact that wastewater plants have some environmental implications. For this reason there are various software designed to do the assessment. Among these is SimaPro software package designed to make a valuable contribution. It is a powerful tool for analyzing the environmental impact to products during their whole life cycle. A huge amount of knowledge about the environment is built into the program and database, enabling to analyze a product with a minimum of specialized knowledge. In this study, Simapro was used to analyze and evaluate the impacts that result from Karbala Wastewater treatment plant. The results of Life Cycle Assessment (LCA) show that Karbala WWTP has an impact and damage on the environment of the order of 171 point for each 1 cubic meter of wastewater. The most environmental impacts potential were global warming, respiratory inorganics and non-renewable energy. The study also showed that most of the effects were as a result of the phase of construction more than of the operational phase.
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