Ensuring the availability and sustainable management of water(SDG 6)is particularly challenging in dry regions like Rajshahi,Bangladesh,where communities rely heavily on groundwater with limited recharge potential.Iss...Ensuring the availability and sustainable management of water(SDG 6)is particularly challenging in dry regions like Rajshahi,Bangladesh,where communities rely heavily on groundwater with limited recharge potential.Issues such as declining water levels and contamination by iron,arsenic,and chloride compromise both user satisfaction and public health.This study aimed to assess groundwater quality risks through regional mapping to guide the installation depth of new water sources.In collaboration with the Department of Public Health Engineering(DPHE),data were collected from 7,388 tube wells across nine upazilas,including well depth,geographic coordinates,and contaminant concentrations.Water quality was evaluated against World Health Organization and Bangladesh standards.Machine learning(XGBoost)and spatial analysis were applied to model contaminant levels based on location and well depth.An initial model showed poor performance,but after identifying and correcting key errors,the refined model yielded significant improvements:R^(2) increased from 0.0345 to 0.62 for iron,from-0.0015 to 0.38 for arsenic,and from 0.12 to 0.71 for chloride.A comprehensive water quality risk map was developed by integrating these results at the upazila level.This map provides actionable insights for government agencies and NGOs to prioritize areas for water quality testing,remediation,and public awareness initiatives,contributing to more informed and sustainable water resource management in the region.展开更多
We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_(0.8)La_(0.2)Fe_(12-x)Ni_(x)O_(19)hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conv...We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_(0.8)La_(0.2)Fe_(12-x)Ni_(x)O_(19)hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization process.An analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)spectrometer.The M-type hexagonal structure of all the samples was confirmed using XRD spectra.The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,respectively.The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,respectively.EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm.The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV.The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 GHz.This high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)sites.The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites.Therefore,we suggest that the prepared samples are suitable for use in magneto-optic applications.展开更多
The continuous rise in CO_(2)emissions from fossil fuel consumption has intensified the search for alternative clean energy sources.Hydrogen produced from renewable sources like ethanol offers a promising alternative ...The continuous rise in CO_(2)emissions from fossil fuel consumption has intensified the search for alternative clean energy sources.Hydrogen produced from renewable sources like ethanol offers a promising alternative to fossil fuels,mitigating CO_(2)emissions.This study investigates the kinetics of hydrogen production via ethanol steam reforming using a nickel-based catalyst,specifically the Ar-401 catalyst.Characterization techniques,including scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy,transmission electron microscopy,Brunauer–Emmett–Teller method,temperature-programmed reduction,and powder X-ray diffraction,were used to analyze the catalyst properties.Under optimal conditions of 973 K,atmospheric pressure,and a steam-to-ethanol ratio of 9,we achieved 100%ethanol conversion,74.8%hydrogen selectivity,and 85%hydrogen yield.Kinetic experiments were conducted under kinetically controlled conditions,examining the effects of temperature(473–673 K)and weight hourly space velocity ranging from 1 to 15(g·h/mol).A power law kinetic model was developed,yielding an activation energy of 11.17 kJ/mol and a reaction order of 0.46,with an absolute average deviation of 3.23%between predicted and experimental rates.This study provides key insights into the reaction mechanisms and highlights the effectiveness of the nickel-based catalyst,providing valuable insights for the design of efficient chemical reactors for sustainable hydrogen production.展开更多
Pyrolysis and gasification are two popular technologies that have been applied for coal utilization for centuries.In recent times,their applications for sustainable coal utilizations have attracted significant interes...Pyrolysis and gasification are two popular technologies that have been applied for coal utilization for centuries.In recent times,their applications for sustainable coal utilizations have attracted significant interest in hydrocarbon-based chemical synthesis,synthetic natural gas production,and carbon material synthesis.However,despite their long history in the coal industry,the underlying chemistries governing the pyrolysis and gasification processes are not well understood.This has contributed to why these technologies have yet to witness widespread commercialization in the coal industry.Therefore,the chemistries of coal pyrolysis and gasification were discussed in this review.It was found that the extent of primary pyrolysis reactions depends on hydrogen because hydrogen stabilizes the free radicals,and its absence slows down or stops the reactions.Operating conditions such as temperature and reactive atmospheres directly affect the pyrolytic reactions and the characteristics of the products,while pressure and particle size affect the mass transfer of volatile species and influence the extent of secondary pyrolysis reactions.In gasification,the composition of the syngas is principally determined by the water-gas-shift and methane-reforming reactions,while operating conditions such as temperature,catalysts,and choice of gasifying agents are used to control the characteristics of the syngas,dictated by the intended application.展开更多
Seeds of Indian mustard （Brassicajuncea （L.） Czern. et Coss.） were exposed to 0, 50, 100 and 150 mmol/L NaCI for 8 h and seeds were sown in an earthen pot. These stressed seedlings were subsequently sprayed with 1...Seeds of Indian mustard （Brassicajuncea （L.） Czern. et Coss.） were exposed to 0, 50, 100 and 150 mmol/L NaCI for 8 h and seeds were sown in an earthen pot. These stressed seedlings were subsequently sprayed with 10μmol/L salicylic acid （SA） at 30 d and were sampled at 60 d to assess the changes in growth, photosynthesis and antioxidant enzymes. The seedlings raised from the seeds treated with NaCI had significantly reduced growth and the activities of carbonic anhydrase, nitrate reductase and photosynthesis, and the decrease was proportional to the increase in NaCI concentration. However, the antioxidant enzymes （catalase, peroxidase and superoxide dismutase） and proline content was enhanced in response to NaCI and/or SA treatment, where their interaction had an additive effect. Moreover, the toxic effects generated by the lower concentration of NaCI （50 mmol/L） were completely overcome by the application of SA. It was, therefore, concluded that SA ameliorated the stress generated by NaCl through the alleviated antioxidant system.展开更多
文摘Ensuring the availability and sustainable management of water(SDG 6)is particularly challenging in dry regions like Rajshahi,Bangladesh,where communities rely heavily on groundwater with limited recharge potential.Issues such as declining water levels and contamination by iron,arsenic,and chloride compromise both user satisfaction and public health.This study aimed to assess groundwater quality risks through regional mapping to guide the installation depth of new water sources.In collaboration with the Department of Public Health Engineering(DPHE),data were collected from 7,388 tube wells across nine upazilas,including well depth,geographic coordinates,and contaminant concentrations.Water quality was evaluated against World Health Organization and Bangladesh standards.Machine learning(XGBoost)and spatial analysis were applied to model contaminant levels based on location and well depth.An initial model showed poor performance,but after identifying and correcting key errors,the refined model yielded significant improvements:R^(2) increased from 0.0345 to 0.62 for iron,from-0.0015 to 0.38 for arsenic,and from 0.12 to 0.71 for chloride.A comprehensive water quality risk map was developed by integrating these results at the upazila level.This map provides actionable insights for government agencies and NGOs to prioritize areas for water quality testing,remediation,and public awareness initiatives,contributing to more informed and sustainable water resource management in the region.
基金supported by the Taif University Researchers Supporting Project number(TURSP-2020/293),Taif University,Taif,Saudi Arabia。
文摘We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_(0.8)La_(0.2)Fe_(12-x)Ni_(x)O_(19)hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization process.An analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)spectrometer.The M-type hexagonal structure of all the samples was confirmed using XRD spectra.The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,respectively.The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,respectively.EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm.The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV.The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 GHz.This high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)sites.The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites.Therefore,we suggest that the prepared samples are suitable for use in magneto-optic applications.
基金supports of the Mitacs Accelerate(IT29592),Proteum Hydrogen Technology,Natural Sciences and Engineering Research Council of Canada(NSERC DG:RGPIN-2024-04760)the Canada Foundation for Innovation(CFI JELF:37758)are gratefully acknowledged。
文摘The continuous rise in CO_(2)emissions from fossil fuel consumption has intensified the search for alternative clean energy sources.Hydrogen produced from renewable sources like ethanol offers a promising alternative to fossil fuels,mitigating CO_(2)emissions.This study investigates the kinetics of hydrogen production via ethanol steam reforming using a nickel-based catalyst,specifically the Ar-401 catalyst.Characterization techniques,including scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy,transmission electron microscopy,Brunauer–Emmett–Teller method,temperature-programmed reduction,and powder X-ray diffraction,were used to analyze the catalyst properties.Under optimal conditions of 973 K,atmospheric pressure,and a steam-to-ethanol ratio of 9,we achieved 100%ethanol conversion,74.8%hydrogen selectivity,and 85%hydrogen yield.Kinetic experiments were conducted under kinetically controlled conditions,examining the effects of temperature(473–673 K)and weight hourly space velocity ranging from 1 to 15(g·h/mol).A power law kinetic model was developed,yielding an activation energy of 11.17 kJ/mol and a reaction order of 0.46,with an absolute average deviation of 3.23%between predicted and experimental rates.This study provides key insights into the reaction mechanisms and highlights the effectiveness of the nickel-based catalyst,providing valuable insights for the design of efficient chemical reactors for sustainable hydrogen production.
文摘Pyrolysis and gasification are two popular technologies that have been applied for coal utilization for centuries.In recent times,their applications for sustainable coal utilizations have attracted significant interest in hydrocarbon-based chemical synthesis,synthetic natural gas production,and carbon material synthesis.However,despite their long history in the coal industry,the underlying chemistries governing the pyrolysis and gasification processes are not well understood.This has contributed to why these technologies have yet to witness widespread commercialization in the coal industry.Therefore,the chemistries of coal pyrolysis and gasification were discussed in this review.It was found that the extent of primary pyrolysis reactions depends on hydrogen because hydrogen stabilizes the free radicals,and its absence slows down or stops the reactions.Operating conditions such as temperature and reactive atmospheres directly affect the pyrolytic reactions and the characteristics of the products,while pressure and particle size affect the mass transfer of volatile species and influence the extent of secondary pyrolysis reactions.In gasification,the composition of the syngas is principally determined by the water-gas-shift and methane-reforming reactions,while operating conditions such as temperature,catalysts,and choice of gasifying agents are used to control the characteristics of the syngas,dictated by the intended application.
文摘Seeds of Indian mustard （Brassicajuncea （L.） Czern. et Coss.） were exposed to 0, 50, 100 and 150 mmol/L NaCI for 8 h and seeds were sown in an earthen pot. These stressed seedlings were subsequently sprayed with 10μmol/L salicylic acid （SA） at 30 d and were sampled at 60 d to assess the changes in growth, photosynthesis and antioxidant enzymes. The seedlings raised from the seeds treated with NaCI had significantly reduced growth and the activities of carbonic anhydrase, nitrate reductase and photosynthesis, and the decrease was proportional to the increase in NaCI concentration. However, the antioxidant enzymes （catalase, peroxidase and superoxide dismutase） and proline content was enhanced in response to NaCI and/or SA treatment, where their interaction had an additive effect. Moreover, the toxic effects generated by the lower concentration of NaCI （50 mmol/L） were completely overcome by the application of SA. It was, therefore, concluded that SA ameliorated the stress generated by NaCl through the alleviated antioxidant system.
