The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,...The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,homogeneous Mg_(17)Al_(12) distribution in LPBF samples,contrasting with the network-like structure in the cast alloy.Electrochemical and hydrogen evolution tests demonstrated no significant anisotropy in LPBF sections,but they exhibited higher corrosion rates than the cast alloy.Potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that the corrosion process was cathodically controlled by the Mg_(17)Al_(12) phase fraction.Scanning vibrating electrode technique further validated these findings,highlighting lower electrochemical activity in cast AZ91 alloy.展开更多
During the non-breeding season(September-April),Black-tailed Godwits(Limosa limosa)are commonly seen in coastal and inland wetlands of the Ganges-Brahmaputra-Meghna Delta in Bangladesh.We hypothesize that the Ganges-B...During the non-breeding season(September-April),Black-tailed Godwits(Limosa limosa)are commonly seen in coastal and inland wetlands of the Ganges-Brahmaputra-Meghna Delta in Bangladesh.We hypothesize that the Ganges-Brahmaputra-Meghna Delta,at the overlap between the Central Asian and East Asian-Australasian flyways,may host three subspecies that breed in disjunct areas of temperate and northern Asia:L.l.limosa,L.l.melanuroides,and L.l.bohaii.We used mitochondrial DNA(mt DNA)haplotype network and biometric analysis to determine subspecies in captured individuals,and deployed GPS-GSM transmitters to verify breeding areas of individuals with subspecies assignments.To test for differential habitat preferences,we sampled birds at two ecologically distinct habitats known to host the largest concentrations of non-breeding Black-tailed Godwits in Bangladesh:Nijhum Dweep National Park,a tidal coastal habitat with brackish water on the south-central coast,and Tanguar Haor(‘backmarsh'),a seasonal freshwater floodplain in the north.During the non-breeding seasons of 2021-2022 and 2022-2023,we sampled and measured 93 Black-tailed Godwits,54 of which were equipped with GPS-GSM transmitters.Our mt DNA haplotype network analysis confirmed the presence of limosa,melanuroides,and bohaii subspecies at the study sites.Thus,indeed,Black-tailed Godwits subspecies,despite having distinct breeding ranges,exhibit(partially)overlapping non-breeding ranges in Asia.The subspecies composition differed significantly between sites,with limosa and bohaii dominating in Tanguar Haor and melanuroides in Nijhum Dweep.Of the 21 individuals that were tracked to their breeding grounds,18 migrated to the expected breeding range of their respective subspecies.However,one bird with a limosa haplotype migrated to a known breeding area of bohaii,whereas two birds with melanuroides haplotypes migrated to the supposed breeding range of limosa.Therefore,while ecological factors at both ends of the flyways may shape the morphological and behavioural differences between Black-tailed Godwit subspecies,their delineations and possible gene flow require further studies.展开更多
Many research results have been reported on the effect of additives on crystal growth rate,but there are few examples comparing multiple crystal growth surfaces,and quantitative data is scarce.In this study,we investi...Many research results have been reported on the effect of additives on crystal growth rate,but there are few examples comparing multiple crystal growth surfaces,and quantitative data is scarce.In this study,we investigated the ef-fect of additives on crystal growth rate.Specifically,we investigated the effect of the additive L-methionine(L-Met)on the growth rate of L-alanine(L-Ala)crystals.We clarified that in the presence of an additive with a structure simi-lar to that of the growing crystal,there are conditions under which crystal growth and dissolution coexist.展开更多
Mechanical stimulation,such as fluid-induced wall shear stress(WSS),is known that can influence the cellular behaviours.Therefore,in some tissue engineering experiments in vitro,mechanical stimulation is applied via b...Mechanical stimulation,such as fluid-induced wall shear stress(WSS),is known that can influence the cellular behaviours.Therefore,in some tissue engineering experiments in vitro,mechanical stimulation is applied via bioreactors to the cells in cell culturing to study cell physiology and pathology.In 3D cell culturing,porous scaffolds are used for housing the cells.It is known that the scaffold porous geometries can influence the scaffold permeability and internal WSS in a bioreactor(such as perfusion bioreactor).To calculate the WSS generated on cells within scaffolds,usually computational fluid dynamics(CFD)simulation is needed.However,the limitations of the computational method for WSS calculation are:(i)the high time cost of the CFD simulation(in particular for the highly irregular geometries);(ii)accessibility to the CFD model for some cell culturing experimentalists due to the knowledge gap.To address these limitations,this study aims to develop an empirical model for calculating the WSS based on scaffold permeability.This model can allow the tissue engineers to efficiently calculate the WSS generated within the scaffold and/or determine the bioreactor loading without performing the computational simulations.展开更多
Although research on biochar has received increasing attention for environmental and agricultural applications,the significance of nanobiochar for environmental pollutant remediation is poorly understood.In contrast t...Although research on biochar has received increasing attention for environmental and agricultural applications,the significance of nanobiochar for environmental pollutant remediation is poorly understood.In contrast to bulk biochar,nanobiochar has superior physicochemical properties such as high catalytic activity,unique nanostructure,large specific surface area and high mobility in the soil environment.These unique characteristics make nanobiochar an ideal candidate for pollution remediation.Thus far,the research on nanobiochar is still in its infancy and most of the previous studies have only been conducted for exploring its properties and environmental functions.The lack of in-depth summary of nanobiochar’s research direction makes it a challenge for scientists and researchers globally.Hence in this review,we established some key fabrication methods for nanobiochar with a focus on its performance for the removal of pollutants from the environment.We also provided up-to-date information on nanobiochar’s role in environmental remediation and insights into different mechanisms involved in the pollutant removal.Although,nanobiochar application is increasing,the associated drawbacks to the soil ecosystem have not received enough research attention.Therefore,further research is warranted to evaluate the potential environmental risks of nanobiochar before large scale application.展开更多
Measurements of proton conductivity in chitin and chitosan have been carried out and proton conductivity is investigated.From the measurement of fuel cell based on the deacetylated chitin(chitosan)electrolyte,it was f...Measurements of proton conductivity in chitin and chitosan have been carried out and proton conductivity is investigated.From the measurement of fuel cell based on the deacetylated chitin(chitosan)electrolyte,it was found that chitosan becomes the electrolyte of fuel cell.This result indicates that chitosan in humidified condition exhibits proton conductivity as seen in chitin.Moreover,proton conductivity in chitin is about 100 times higher than that in chitosan.These results indicate that acetyl group is an important factor for the appearance of higher proton conductivity in chitin system.In addition,the anisotropy of proton conductivity in chitosan is much larger than that in the orientated chitin.Considering that proton conductivity is caused by proton transfer in water bridges,these results indicate that chitin and chitosan possess quasi-three dimensional water bridges and quasi-two dimensional water bridges,respectively.It is deduced from these results that acetyl group is a key factor not only the appearance of higher proton conductivity but also the realization of quasi-three dimensional proton conductivity.展开更多
基金the financial support under the Project PID2021-126166OB-I00 funded by MCIN/AEI/10.13039/501100011033 and by“ERDF A way of making Europe”(European Union)the Grant CNS2023-144665 funded by MCIN/AEI/10.13039/501100011033+1 种基金by the“European Union NextGenerationEU/PRTR.”the CSIC for the financial support under the project PIE-20216AT012.
文摘The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,homogeneous Mg_(17)Al_(12) distribution in LPBF samples,contrasting with the network-like structure in the cast alloy.Electrochemical and hydrogen evolution tests demonstrated no significant anisotropy in LPBF sections,but they exhibited higher corrosion rates than the cast alloy.Potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that the corrosion process was cathodically controlled by the Mg_(17)Al_(12) phase fraction.Scanning vibrating electrode technique further validated these findings,highlighting lower electrochemical activity in cast AZ91 alloy.
基金supported by The Embassy of the Royal Kingdom of the Netherlands in Dhaka,The Embassy of France in Dhaka,and Bangabandhu Science and Technology Fellowship Trust,MoST,Bangladesh。
文摘During the non-breeding season(September-April),Black-tailed Godwits(Limosa limosa)are commonly seen in coastal and inland wetlands of the Ganges-Brahmaputra-Meghna Delta in Bangladesh.We hypothesize that the Ganges-Brahmaputra-Meghna Delta,at the overlap between the Central Asian and East Asian-Australasian flyways,may host three subspecies that breed in disjunct areas of temperate and northern Asia:L.l.limosa,L.l.melanuroides,and L.l.bohaii.We used mitochondrial DNA(mt DNA)haplotype network and biometric analysis to determine subspecies in captured individuals,and deployed GPS-GSM transmitters to verify breeding areas of individuals with subspecies assignments.To test for differential habitat preferences,we sampled birds at two ecologically distinct habitats known to host the largest concentrations of non-breeding Black-tailed Godwits in Bangladesh:Nijhum Dweep National Park,a tidal coastal habitat with brackish water on the south-central coast,and Tanguar Haor(‘backmarsh'),a seasonal freshwater floodplain in the north.During the non-breeding seasons of 2021-2022 and 2022-2023,we sampled and measured 93 Black-tailed Godwits,54 of which were equipped with GPS-GSM transmitters.Our mt DNA haplotype network analysis confirmed the presence of limosa,melanuroides,and bohaii subspecies at the study sites.Thus,indeed,Black-tailed Godwits subspecies,despite having distinct breeding ranges,exhibit(partially)overlapping non-breeding ranges in Asia.The subspecies composition differed significantly between sites,with limosa and bohaii dominating in Tanguar Haor and melanuroides in Nijhum Dweep.Of the 21 individuals that were tracked to their breeding grounds,18 migrated to the expected breeding range of their respective subspecies.However,one bird with a limosa haplotype migrated to a known breeding area of bohaii,whereas two birds with melanuroides haplotypes migrated to the supposed breeding range of limosa.Therefore,while ecological factors at both ends of the flyways may shape the morphological and behavioural differences between Black-tailed Godwit subspecies,their delineations and possible gene flow require further studies.
文摘Many research results have been reported on the effect of additives on crystal growth rate,but there are few examples comparing multiple crystal growth surfaces,and quantitative data is scarce.In this study,we investigated the ef-fect of additives on crystal growth rate.Specifically,we investigated the effect of the additive L-methionine(L-Met)on the growth rate of L-alanine(L-Ala)crystals.We clarified that in the presence of an additive with a structure simi-lar to that of the growing crystal,there are conditions under which crystal growth and dissolution coexist.
基金This study was supported by the Royal Society Research Grant(reference code:RGS/R2/212,280)Swansea University IMPACT–Green Recovery funding.Matthew Bedding-Tyrrell is supported by EPSRC–Doctoral Training Partnership(DTP)scholarship(reference code:EP/T517987/1-2573181)。
文摘Mechanical stimulation,such as fluid-induced wall shear stress(WSS),is known that can influence the cellular behaviours.Therefore,in some tissue engineering experiments in vitro,mechanical stimulation is applied via bioreactors to the cells in cell culturing to study cell physiology and pathology.In 3D cell culturing,porous scaffolds are used for housing the cells.It is known that the scaffold porous geometries can influence the scaffold permeability and internal WSS in a bioreactor(such as perfusion bioreactor).To calculate the WSS generated on cells within scaffolds,usually computational fluid dynamics(CFD)simulation is needed.However,the limitations of the computational method for WSS calculation are:(i)the high time cost of the CFD simulation(in particular for the highly irregular geometries);(ii)accessibility to the CFD model for some cell culturing experimentalists due to the knowledge gap.To address these limitations,this study aims to develop an empirical model for calculating the WSS based on scaffold permeability.This model can allow the tissue engineers to efficiently calculate the WSS generated within the scaffold and/or determine the bioreactor loading without performing the computational simulations.
基金National Natural Science Foundation of China(42107245)China Postdoctoral Science Foundation(2021M701455).
文摘Although research on biochar has received increasing attention for environmental and agricultural applications,the significance of nanobiochar for environmental pollutant remediation is poorly understood.In contrast to bulk biochar,nanobiochar has superior physicochemical properties such as high catalytic activity,unique nanostructure,large specific surface area and high mobility in the soil environment.These unique characteristics make nanobiochar an ideal candidate for pollution remediation.Thus far,the research on nanobiochar is still in its infancy and most of the previous studies have only been conducted for exploring its properties and environmental functions.The lack of in-depth summary of nanobiochar’s research direction makes it a challenge for scientists and researchers globally.Hence in this review,we established some key fabrication methods for nanobiochar with a focus on its performance for the removal of pollutants from the environment.We also provided up-to-date information on nanobiochar’s role in environmental remediation and insights into different mechanisms involved in the pollutant removal.Although,nanobiochar application is increasing,the associated drawbacks to the soil ecosystem have not received enough research attention.Therefore,further research is warranted to evaluate the potential environmental risks of nanobiochar before large scale application.
基金This work was partially supported by JSPS KAKENHI Grant Number 18K11741.
文摘Measurements of proton conductivity in chitin and chitosan have been carried out and proton conductivity is investigated.From the measurement of fuel cell based on the deacetylated chitin(chitosan)electrolyte,it was found that chitosan becomes the electrolyte of fuel cell.This result indicates that chitosan in humidified condition exhibits proton conductivity as seen in chitin.Moreover,proton conductivity in chitin is about 100 times higher than that in chitosan.These results indicate that acetyl group is an important factor for the appearance of higher proton conductivity in chitin system.In addition,the anisotropy of proton conductivity in chitosan is much larger than that in the orientated chitin.Considering that proton conductivity is caused by proton transfer in water bridges,these results indicate that chitin and chitosan possess quasi-three dimensional water bridges and quasi-two dimensional water bridges,respectively.It is deduced from these results that acetyl group is a key factor not only the appearance of higher proton conductivity but also the realization of quasi-three dimensional proton conductivity.
