| 21. |
- Kakkar, Manish, et al.
(författare)
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Antimicrobial resistance in South East Asia : time to ask the right questions
- 2018
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Ingår i: Global Health Action. - : Informa UK Limited. - 1654-9716 .- 1654-9880. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial resistance (AMR) has emerged as a major public health concern, around which the international leadership has come together to form strategic partnerships and action plans. The main driving force behind the emergence of AMR is selection pressure created due to consumption of antibiotics. Consumption of antibiotics in human as well as animal sectors are driven by a complex interplay of determinants, many of which are typical to the local settings. Several sensitive and essential realities are tied with antibiotic consumption - food security, livelihoods, poverty alleviation, healthcare access and national economies, to name a few. That makes one-size-fits-all policies, framed with the developed country context in mind, inappropriate for developing countries. Many countries in the South East Asian Region have some policy structures in place to deal with AMR, but most of them lack detailed implementation plans or monitoring structures. In this current debates piece, the authors argue that the principles driving the AMR agenda in the South East Asian countries need to be dealt with using locally relevant policy structures. Strategies, which have successfully reduced the burden of AMR in the developed countries, should be evaluated in the developing country contexts instead of ad hoc implementation. The Global Action Plan on AMR encourages member states to develop locally relevant National Action Plans on AMR. This policy position should be leveraged to develop and deploy locally relevant strategies, which are based on a situation analysis of the local systems, and are likely to meet the needs of the individual member states.
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| 22. |
- Kumar, Manish, et al.
(författare)
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Arsenic enrichment in groundwater in the middle Gangetic Plain of Ghazipur District in Uttar Pradesh, India
- 2010
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Ingår i: Journal of Geochemical Exploration. - : Elsevier BV. - 0375-6742 .- 1879-1689. ; 105:3, s. 83-94
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater with high geogenic arsenic (As) is extensively present in the Holocene alluvial aquifers of Ghazipur District in the middle Gangetic Plain, India. A shift in the climatic conditions, weathering of carbonate and silicate minerals, surface water interactions, ion exchange, redox processes, and anthropogenic activities are responsible for high concentrations of cations, anions and As in the groundwater. The spatial and temporal variations for As concentrations were greater in the pre-monsoon (6.4-259.5 mu g/L) when compared to the post-monsoon period (5.1-205.5 mu g/L). The As enrichment was encountered in the sampling sites that were close to the Ganges River (i.e. south and southeast part of Ghazipur district). The depth profile of As revealed that low concentrations of NO3- are associated with high concentration of As and that As depleted with increasing depth. The poor relationship between As and Fe indicates the As release into the groundwater, depends on several processes such as mineral weathering, O-2 consumption, and NO3- reduction and is de-coupled from Fe cycling. Correlation matrix and factor analysis were used to identify various factors influencing the gradual As enrichment in the middle Gangetic Plain. Groundwater is generally supersaturated with respect to calcite and dolomite in post-monsoon period, but not in pre-monsoon period. Saturation in both periods is reached for crystalline Fe phases such as goethite, but not with respect to poorly crystalline Fe phases and any As-bearing phase. The results indicate release of arsenic in redox processes in dry period and dilution of arsenic concentration by recharge during monsoon. Increased concentrations of bicarbonate after monsoon are caused by intense flushing of unsaturated zone, where CO2 is formed by decomposition of organic matter and reactions with carbonate minerals in solid phase. The present study is vital considering the fact that groundwater is an exclusive source of drinking water in the region which not only makes situation alarming but also calls for the immediate attention.
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| 23. |
- Kumar, Rakesh, et al.
(författare)
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Rice husk biochar-A novel engineered bio-based material for transforming groundwater-mediated fluoride cycling in natural environments
- 2023
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 343
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Tidskriftsartikel (refereegranskat)abstract
- Biochar, a promising carbon-rich and carbon-negative material, can control water pollution, harness the synergy of sustainable development goals, and achieve circular economy. This study examined the performance feasibility of treating fluoride-contaminated surface and groundwater using raw and modified biochar synthesized from agricultural waste rice husk as problem-fixing renewable carbon-neutral material. Physicochemical characterizations of raw/modified biochars were investigated using FESEM-EDAX, FTIR, XRD, BET, CHSN, VSM, pHpzc, Zeta potential, and particle size analysis were analyzed to identify the surface morphology, functional groups, structural, and electrokinetic behavior. In fluoride (Fˉ) cycling, performance feasibility was tested at various governing factors, contact time (0–120 min), initial Fˉ levels (10–50 mg L−1), biochar dose (0.1–0.5 g L−1), pH (2–9), salt strengths (0–50 mM), temperatures (301–328 K), and various co-occurring ions. Results revealed that activated magnetic biochar (AMB) possessed higher adsorption capacity than raw biochar (RB) and activated biochar (AB) at pH 7. The results indicated that maximum Fˉ removal (98.13%) was achieved using AMB at pH 7 for 10 mg L−1. Electrostatic attraction, ion exchange, pore fillings, and surface complexation govern Fˉ removal mechanisms. Pseudo-second-order and Freundlich were the best fit kinetic and isotherm for Fˉ sorption, respectively. Increased biochar dose drives an increase in active sites due to Fˉ level gradient and mass transfer between biochar-fluoride interactions, which reported maximum mass transfer for AMB than RB and AB. Fluoride adsorption using AMB could be described through chemisorption processes at room temperature (301 K), though endothermic sorption follows the physisorption process. Fluoride removal efficiency reduced, from 67.70% to 53.23%, with increased salt concentrations from 0 to 50 mM NaCl solutions, respectively, due to increased hydrodynamic diameter. Biochar was used to treat natural fluoride-contaminated surface and groundwater in real-world problem-solving measures, showed removal efficiency of 91.20% and 95.61%, respectively, for 10 mg L−1 Fˉ contamination, and has been performed multiple times after systematic adsorption-desorption experiments. Lastly, techno-economic analysis was analyzed for biochar synthesis and Fˉ treatment performance costs. Overall, our results revealed worth output and concluded with recommendations for future research on Fˉ adsorption using biochar.
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| 24. |
- Li, Yihang, et al.
(författare)
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Efficient reversible CO/CO2 conversion in solid oxide cells with a phase-transformed fuel electrode
- 2021
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Ingår i: SCIENCE CHINA Materials. - : Springer Science and Business Media LLC. - 2095-8226 .- 2199-4501. ; 64:5, s. 1114-1126
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Tidskriftsartikel (refereegranskat)abstract
- The reversible solid oxide cell (RSOC) is an attractive technology to mutually convert power and chemicals at elevated temperatures. However, its development has been hindered mainly due to the absence of a highly active and durable fuel electrode. Here, we report a phase-transformed CoFe-Sr3Fe1.25Mo0.75O7−δ (CoFe-SFM) fuel electrode consisting of CoFe nanoparticles and Ruddlesden-Popper-layered Sr3Fe1.25Mo0.75O7−δ (SFM) from a Sr2Fe7/6Mo0.5Co1/3O6−δ (SFMCo) perovskite oxide after annealing in hydrogen and apply it to reversible CO/CO2 conversion in RSOC. The CoFe-SFM fuel electrode shows improved catalytic activity by accelerating oxygen diffusion and surface kinetics towards the CO/CO2 conversion as demonstrated by the distribution of relaxation time (DRT) study and equivalent circuit model fitting analysis. Furthermore, an electrolyte-supported single cell is evaluated in the 2:1 CO-CO2 atmosphere at 800°C, which shows a peak power density of 259 mW cm−2 for CO oxidation and a current density of −0.453 A cm−2 at 1.3 V for CO2 reduction, which correspond to 3.079 and 3.155 mL min−1 cm−2 for the CO and CO2 conversion rates, respectively. More importantly, the reversible conversion is successfully demonstrated over 20 cyclic electrolysis and fuel cell switching test modes at 1.3 and 0.6 V. This work provides a useful guideline for designing a fuel electrode through a surface/interface exsolution process for RSOC towards efficient CO-CO2 reversible conversion.
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| 25. |
- Liu, Liang, et al.
(författare)
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The composite electrolyte with an insulation Sm2O3 and semiconductor NiO for advanced fuel cells
- 2018
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12739-12747
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Tidskriftsartikel (refereegranskat)abstract
- Novel Sm2O3-NiO composite was prepared as the functional electrolyte for the first time. The total electrical conductivity of Sm2O3-NiO is 0.38 S cm(-1) in H-2/air condition at 550 degrees C. High performance, e.g. 718 mW cm(-2), was achieved using Sm2O3-NiO composite as an electrolyte of solid oxide fuel cells operated at 550 degrees C. The electrical properties and electrochemical performance are strongly depended on Sm2O3 and NiO constituent phase of the compositions. Notably, surprisingly high ionic conductivity and fuel cell performance are achieved using the composite system constituting with insulating Sm2O3 and intrinsic p-type conductive NiO with a low conductivity of 4 x 10(-3) S cm(-1). The interfacial ionic conduction between two phases is a dominating factor giving rise to significantly enhanced proton conduction. Fuel cell performance and further ionic conduction mechanisms are under investigation.
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| 26. |
- Liu, Yanyan, et al.
(författare)
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Flowerlike CeO2 microspheres coated with Sr2Fe1.5Mo0.5Ox nanoparticles for an advanced fuel cell
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Flowerlike CeO2 coated with Sr(2)Fe(1.5)Mo(0.5)Ox (Sr-Fe-Mo-oxide) nanoparticles exhibits enhanced conductivity at low temperatures (300-600 degrees C), e.g. 0.12 S cm(-1) at 600 degrees C, this is comparable to pure ceria (0.1 S cm(-1) at 800 degrees C). Advanced single layer fuel cell was constructed using the flowerlike CeO2/Sr-Fe-Mo-oxide layer attached to a Ni-foam layer coated with the conducting transition metal oxide. Such fuel cell has yielded a peak power density of 802 mWcm(-2) at 550 degrees C. The mechanism of enhanced conductivity and cell performance were analyzed. These results provide a promising strategy for developing advanced low-temperature SOFCs.
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| 27. |
- Liu, Yanyan, et al.
(författare)
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Natural CuFe2O4 mineral for solid oxide fuel cells
- 2017
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 42:27, s. 17514-17521
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Tidskriftsartikel (refereegranskat)abstract
- Natural mineral, cuprospinel (CuFe2O4) originated from natural chalcopyrite ore (CuFeS2), has been used for the first time in low temperature solid oxide fuel cells. Three different types of devices are fabricated to explore the optimum application of CuFe2O4 in fuel cells. Device with CuFe2O4 as a cathode catalyst exhibits a maximum power density of 180 mW/cm(2) with an open circuit voltage 1.07 V at 550 degrees C. And a power output of 587 mW/cm(2) is achieved from the device using a homogeneous mixture membrane of CuFe2O4, Li2O-ZnO-Sm0.2Ce0.8O2 and LiNi0.8Co0.15Al0.05O2. Electrochemical impedance spectrum analysis reveals different mechanisms for the devices. The results demonstrate that natural mineral, chalcopyrite, can provide a new implementation to utilize the natural resources for next generation fuel cells being cost-effective and make great contributions to the environmentally friendly sustainable energy.
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| 28. |
- Ma, Ying, et al.
(författare)
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Study on GDC-KZnAl composite electrolytes for low-temperature solid oxide fuel cells
- 2014
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 39:30, s. 17460-17465
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Tidskriftsartikel (refereegranskat)abstract
- Development of low-temperature solid oxide fuel cells (LTSOFC) is now becoming a mainstream research direction worldwide. The advancement in the effective electrolyte materials has been one of the major challenges for LTSOFC development. To further improve the performance of electrolyte, composite approaches are considered as common strategies. The enhancement on ionic conductivity or sintering behavior ceria-based electrolyte can either be done by adding a carbonate phase to facilitate the utilization of the ionic-conducting interfaces, or by addition of alumina as insulator to reduce the electronic conduction of ceria. Thus the present report aims to design a composite electrolyte materials by combining the above two composite approaches, in order to enhance the ionic conductivity and to improve the long-term stability simultaneously. Here we report the preparation and investigation of GDC-KAlZn materials with composition of Gd doped ceria, K2CO3, ZnO and Al2O3. The structure and morphology of the samples were characterized by XRD, SEM, etc. The ionic conductivity of GDC-KAlZn sample was determined by impedance spectroscopy. The composite samples with various weight ratio of GDC and KAlZn were used as electrolyte material to fabricate and evaluate fuel cells as well as investigate the composition dependent properties. The good ionic conductivity and notable fuel cell performance of 480 mW cm(-2) at 550 degrees C has demonstrated that GDC-KAlZn composite electrolyte can be regarded as a potential electrolyte material for LTSOFCs.
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| 29. |
- Qin, Haiying, et al.
(författare)
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Direct biofuel low-temperature solid oxide fuel cells
- 2011
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Ingår i: ENERGY & ENVIRONMENTAL SCIENCE. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4:4, s. 1273-1276
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Tidskriftsartikel (refereegranskat)abstract
- A low-temperature solid oxide fuel cell system was developed to use bioethanol and glycerol as fuels directly. This system achieved a maximum power density of 215 mW cm(-2) by using glycerol at 580 degrees C and produced a great impact on sustainable energy and the environment.
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| 30. |
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