| 1. |
- Ahlström, A. P., et al.
(författare)
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Historically unprecedented global glacier decline in the early 21st century
- 2015
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Ingår i: Journal of Glaciology. - 0022-1430 .- 1727-5652. ; 61:228, s. 745-
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Tidskriftsartikel (refereegranskat)abstract
- Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (similar to 42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (similar to 5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.
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| 2. |
- Abbas, Ghazanfar, et al.
(författare)
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Electrochemical investigation of mixed metal oxide nanocomposite electrode for low temperature solid oxide fuel cell
- 2017
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Ingår i: International Journal of Modern Physics B. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0217-9792. ; 31:27
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Tidskriftsartikel (refereegranskat)abstract
- Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn-0.60/CU0.20Mn0.20 oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer's equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600 degrees C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1 mm thickness of the symmetric fuel cell were fabricated by dry pressing. The maximum power density of 728.86 mW/cm(2) was measured at 550 degrees C.
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| 3. |
- Hussain, Fida, et al.
(författare)
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A modeling approach for low-temperature SOFC-based micro-combined heat and power systems
- 2019
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Ingår i: International Journal of Modern Physics B. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0217-9792. ; 33:4
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Tidskriftsartikel (refereegranskat)abstract
- The world's challenge is to determine a more efficient, economical and environmental-friendly energy source to compete and replace the ongoing conventional energy resources. Solid oxide fuel cells (SOFCs) provide a highly efficient system to use divergent energy resources and have proved to provide the cleanest energy, least energy use, and lowest emissions. A techno-economic study is required to investigate the model design for SOFC-based micro-combined heat and power (m-CHP) systems for applications in terms of educational and commercial buildings. This work models and explores the optimized application of hydrogen gas-fueled SOFC-based m-CHP systems in educational buildings. Two educational departments' loads are presented and model of SOFC-based m-CHP system against the different electric power demands is performed, in order to provide a techno-economic assessment of the technology. For successful development of the technology, results are related to system rightsizing, operating strategies, thermal to electric ratios, and match between end-use, with an aim towards classifying the overall feasibility and essential application requirements.
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| 4. |
- Muus, Christoph, et al.
(författare)
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Single-cell meta-analysis of SARS-CoV-2 entry genes across tissues and demographics
- 2021
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 27:3, s. 546-559
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin-converting enzyme 2 (ACE2) and accessory proteases (TMPRSS2 and CTSL) are needed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cellular entry, and their expression may shed light on viral tropism and impact across the body. We assessed the cell-type-specific expression of ACE2, TMPRSS2 and CTSL across 107 single-cell RNA-sequencing studies from different tissues. ACE2, TMPRSS2 and CTSL are coexpressed in specific subsets of respiratory epithelial cells in the nasal passages, airways and alveoli, and in cells from other organs associated with coronavirus disease 2019 (COVID-19) transmission or pathology. We performed a meta-analysis of 31 lung single-cell RNA-sequencing studies with 1,320,896 cells from 377 nasal, airway and lung parenchyma samples from 228 individuals. This revealed cell-type-specific associations of age, sex and smoking with expression levels of ACE2, TMPRSS2 and CTSL. Expression of entry factors increased with age and in males, including in airway secretory cells and alveolar type 2 cells. Expression programs shared by ACE2(+)TMPRSS2(+) cells in nasal, lung and gut tissues included genes that may mediate viral entry, key immune functions and epithelial-macrophage cross-talk, such as genes involved in the interleukin-6, interleukin-1, tumor necrosis factor and complement pathways. Cell-type-specific expression patterns may contribute to the pathogenesis of COVID-19, and our work highlights putative molecular pathways for therapeutic intervention. An integrated analysis of over 100 single-cell and single-nucleus transcriptomics studies illustrates severe acute respiratory syndrome coronavirus 2 viral entry gene coexpression patterns across different human tissues, and shows association of age, smoking status and sex with viral entry gene expression in respiratory cell populations.
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| 5. |
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| 6. |
- Abbas, Ghazanfar, et al.
(författare)
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Electrochemical study of nanostructured electrode for low-temperature solid oxide fuel cell (LTSOFC)
- 2014
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 518-523
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Tidskriftsartikel (refereegranskat)abstract
- Zn-based nanostructured Ba0.05Cu0.25Fe0.10Zn0.60O (BCFZ) oxide electrode material was synthesized by solid-state reaction for low-temperature solid oxide fuel cell. The cell was fabricated by sandwiching NK-CDC electrolyte between BCFZ electrodes by dry press technique, and its performance was assessed. The maximum power density of 741.87 mW-cm(-2) was achieved at 550 degrees C. The crystal structure and morphology were characterized by X-ray diffractometer (XRD) and SEM. The particle size was calculated to be 25 nm applying Scherer's formula from XRD data. Electronic conductivities were measured with the four-probe DC method under hydrogen and air atmosphere. AC Electrochemical Impedance Spectroscopy of the BCFZ oxide electrode was also measured in hydrogen atmosphere at 450 degrees C.
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| 7. |
- Abbas, Ghazanfar, et al.
(författare)
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Synthesize and characterization of nanocomposite anodes for low temperature solid oxide fuel cell
- 2015
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 40:1, s. 891-897
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Tidskriftsartikel (refereegranskat)abstract
- Solid oxide fuel cells have much capability to become an economical alternative energy conversion technology having appropriate materials that can be operated at comparatively low temperature in the range of 400-600 degrees C. The nano-scale engineering has been incorporated to improve the catalytic activity of anode materials for solid oxide fuel cells. Nanostructured Al0.10NixZn0.90-xO oxides were prepared by solid state reaction, which were then mixed with the prepared Gadolinium doped Ceria GDC electrolyte. The crystal structure and surface morphology were characterized by XRD and SEM. The particle size was evaluated by XRD data and found in the range of 20-50 nm, which was then ensured by SEM pictures. The pellets of 13 mm diameter were pressed by dry press technique and electrical conductivities (DC and AC) were determined by four probe techniques and the values have been found to be 10.84 and 4.88 S/cm, respectively at hydrogen atmosphere in the temperature range of 300-600 degrees C. The Electrochemical Impedance Spectroscopy (EIS) analysis exhibits the pure electronic behavior at hydrogen atmosphere. The maximum power density of ANZ-GDC composite anode based solid oxide fuel cell has been achieved 705 mW/cm(2) at 550 degrees C.
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| 8. |
- Afroz, Laila, et al.
(författare)
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Nanocomposite Catalyst (1 – x)NiO-xCuO/yGDC for Biogas Fueled Solid Oxide Fuel Cells
- 2023
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 6:21, s. 10918-10928
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Tidskriftsartikel (refereegranskat)abstract
- The composites of Ni–Cu oxides with gadolinium doped ceria (GDC) are emerging as highly proficient anode catalysts, owing to their remarkable performance for solid oxide fuel cells operated with biogas. In this context, the nanocomposite catalysts (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3) are synthesized using a solid-state reaction route. The cubic and monoclinic structures are observed for NiO and CuO phases, respectively, while CeO2 showed cubic fluorite structure. The scanning electron microscopic images revealed a rise in the particle size with an increase in the copper and GDC concentration. The optical band gap values are calculated in the range 2.82–2.33 eV from UV–visible analysis. The Raman spectra confirmed the presence of vibration modes of CeO2 and NiO. The electrical conductivity of the nanocomposite anodes is increased as the concentration of copper and GDC increased and reached at 9.48 S cm–1 for 0.2NiO-0.8CuO/1.3GDC composition at 650 °C. The electrochemical performance of (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3)-based fuel cells is investigated with biogas fuel at 650 °C. Among all of the as-synthesized anodes, the fuel cell with composition 0.2NiO-0.8CuO/1.3GDC showed the best performance, such as an open circuit voltage of 0.84 V and peak power density of 72 mW cm–2. However, from these findings, it can be inferred that among all other compositions, the 0.2NiO-0.8CuO/1.3GDC anode is a superior combination for the high electrochemical performance of solid oxide fuel cells fueled with biogas.
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