In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]...In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.展开更多
Conversion of rice straw (RS) as one of agricultural plant wastes (about 45% of the volume of rice production) to valuable industrial product was achieved, by grafting different amounts of dimethylaminoethyl methacryl...Conversion of rice straw (RS) as one of agricultural plant wastes (about 45% of the volume of rice production) to valuable industrial product was achieved, by grafting different amounts of dimethylaminoethyl methacrylate (DMAEM) on it using potassium permanganate/nitric acid redox system. This was done to obtain six levels of poly (DMAEM)—rice straw graft copolymers (PDMAEMRS) having different graft yields (expressed as N%) with increasing order and designated as (PDMAEMRS 1 to PDMAEMRS 6). The latter copolymers were dispersed in aqueous solution of heavy metal ions Cu (II) ions and filtered to form rice straw co-polymer—metal ions complex. Different factors affecting the heavy metal ions removal such as pH, extent of grafting, treatment time and rice straw dose were studied in detail. It was found from the obtained results that;the residual metal ions removal from their aqueous solutions increased with 1) increasing the extent of grafting of PDMAEMRS i.e. from PDMAEMRS 1 to PDMAEMRS 6;2) increasing the pH of the metal ions solution complex from 1 to 8;3) increasing the rice straw dosage from 0.50 to 2.0 g, then leveled off thereafter;4) increasing the time of the reaction up to 20 minute then leveled off after that. On the other hand, Pb (II), Cd (II) and Hg (II) ions were also removed from their solutions with different extent. Furthermore, the prepared co-polymer could be recovered by washing the metal ions from the complex with weak acid 1 N HNO3 (pH 2) and the metal-binding activity of the rice straw was slightly reduced by this process. Finally, the ability of PDMAEMRS to remove three types of acid dyes from their solutions was also reported.展开更多
Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structur...Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structure with the top MgCO_(3)/MgO-intermixed particulates pillars and the bottom dense layer.The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules,plasma-active CO_(2) molecules,and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer.The resulting surfaces after CO_(2)-AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion.For the hydrophobic surfaces of CO_(2)-AP treated Mg,molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source.The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment,generation of by-product,and supply of raw material.展开更多
Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively....Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.展开更多
We explored the possibility of using ionic liquids (ILs) as medium for efficient extraction of agarose via dissolution of red algae under varying conditions of heating or microwave irradiation. As compared to conventi...We explored the possibility of using ionic liquids (ILs) as medium for efficient extraction of agarose via dissolution of red algae under varying conditions of heating or microwave irradiation. As compared to conventional methods, a very high extraction yield of good quality agarose (as high as 39 wt%) could be achieved depending upon the nature of used IL and applied experimental conditions. Purity of extracted agarose was confirmed from various spectral and analytical techniques, such as 1H and 13C NMR, FTIR, circular dichroism (CD), gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The physicochemical properties, such as gelling or melting temperature, viscosity and gel strength of extracted agarose hydrogels have been measured and compared with the agarose obtained from similar source reported in the literature. ILs were recovered after the extraction of agarose and were reused for further extraction experiments. % Recycling and extraction ability of recycled ILs in different cycles have been measured. The developed extraction process of utilizing ILs as medium is easy, simple and highly efficient as compared to the conventional methods of agarose extraction from algae.展开更多
Research on the occurrence of perfluorochemicals (PFCs) such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the agricultural environment is lacking, in spite of their potential risk ...Research on the occurrence of perfluorochemicals (PFCs) such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the agricultural environment is lacking, in spite of their potential risk via food chain transfer from aquatic and soil-plant systems to animals and/or humans. In the present study, for the first time, soil and water samples collected from 243 different agricultural sites adjacent to waste water treatment plants (WWTPs) belonging to 81 cities and 5 provinces with different levels of industrialization in South Korea were monitored for concentrations of PFOS and PFOA by use of solid phase extraction and liquid chromatography-tandem mass spectroscopy (LC-MS/MS). Significant mean concentrations of PFOA (0.001-0.007 tJg L-1 water and 〈0.05-1.573 tJg kg-1 soil) and PFOS (0.001-0.22 tJg L-1 water and 〈0.05-0.741 pg kg-1 soil) were found in all samples. Concentrations of PFCs in soils were high, highlighting that soil is an important sink for PFCs in the agricultural environment. Samples from near WWTPs in Gyeongsang Province contained the highest concentrations of PFOS and PFOA, reflecting the concentration of heavy industry in the province. The concentrations of PFCs in agricultural water (most samples 〈0.05 pg L-~) and soils (most samples 〈1 IJg kg-~) from South Korea were less than acceptable guideline values, indicating that South Korea is not a hotspot of PFOS and PFOA contamination and that there is negligible risk to human and ecological health from these chemicals. However, further studies investigating the seasonal variation in PFOA, PFOS and other perfluorochemical concentrations in the agricultural environment are needed.展开更多
Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and e...Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and evaluation of electrochemical performance in prototype 1.5 Ah pouch cells.Thick LiNi0.5Mn0.3Co0.2O2(NMC532)composite electrodes with an areal loading of 25 mg cm^-2(~4 mAh cm^-2)are successfully cured at a line speed of 500 feet per minute at 275 keV.Compared to the NMC532 cathode processed via a conventional coating method,the electron beam cured electrodes show higher capacity fade in the first 100 cycles,but similar fade rate afterwards.Further improvement strategies are proposed and discussed.This work demonstrates that electron beam curing is a promising method for manufacturing thick battery electrodes at high speeds and low capital/operation cost.展开更多
Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon c...Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst (SC) despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.展开更多
Protective coatings are essential for superalloys to serve as blades of gas turbines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystal...Protective coatings are essential for superalloys to serve as blades of gas turbines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high temperature oxidation law of aluminide coatings.展开更多
An important way to address global food security is to make better use of the food already produced. Since at least one third of global food is wasted before consumption, there are enormous incentives to cut this wast...An important way to address global food security is to make better use of the food already produced. Since at least one third of global food is wasted before consumption, there are enormous incentives to cut this waste and create a more sustainable food system. This paper focuses upon saving food loss at the supermarket level in the US and channeling this food stream in new and efficient ways to those in hunger. A more comprehensive Food System-Sensitive Methodology has been used to pilot and evaluate a surplus food management program that diverts culled fresh fruits and vegetables from grocery stores that would otherwise be disposed of in landfills. Instead, produce is processed for donation or for new businesses. Nearly 35,000 pounds of produce was culled from a grocery store chain in Philadelphia. Twenty-five percent of this was not suitable for culinary uses, ten percent consisted of relatively small quantities of food that did not warrant further research, and about 33 percent is suitable for use at area food shelters and pantries. An experimental sample taken from the remaining 15,000 pounds was used for recipe research and development for diversion to new commercial enterprises. We analyzed a scenario where a supermarket receives $0.25 per pound for culled produce, generating about $8700 dollars in average monthly revenue while eliminating disposal costs. New commercial possibilities for the unused food were then explored. The scenario included community-based enterprises that could process the produce into value-added products that could be wholesaled back to the store at sufficient profits to support 2 - 4 community employees. Extrapolating these results to the approximately 38,000 large supermarkets in the United States suggests that much of the 1,100,000,000 pounds of produce that is currently sent to landfills can be repurposed. If diverted to new foods each of the 46.1 million SNAP recipients could figuratively receive an equivalent of 24 pounds of fruit and vegetable products per annum. This initial analysis suggests that repurposing surplus produce from supermarket discards can have significant beneficial outcomes for new food markets and the environment.展开更多
In recent years there has been increasing demand for natural non-nutritive high intensity sweeteners with low-calorie value as an alternative to sucrose. Extracts of the leaves of Stevia rebaudiana (Bertoni), have bee...In recent years there has been increasing demand for natural non-nutritive high intensity sweeteners with low-calorie value as an alternative to sucrose. Extracts of the leaves of Stevia rebaudiana (Bertoni), have been known for their sweet taste. Steviosides and rebaudioside-A are the two major diterpenoid glucosides components present in the leaf extracts of the stevia, these glycosides are 300 times sweeter than sugar and also exhibits wide therapeutic activity. The conventional methods of isolation of steviosides involve long extraction and purification procedures;therefore optimization of product yields is a challenging problem. The present study, establishes a new improvised process of extraction of steviosides from the stevia leaves in which the dry treated leaves were grounded, defatted, and extracted through pressurized hot water extractor (PHWE), followed by purification and concentration of the sweet glycosides through ultra (UF) and nano (NF) membrane filtration in obtaining high (98.2%) purity steviosides. This process established “green” method for isolation of high quality steviol glycosides, with improved final yield is 10.1% from 11% of crude leaf extract and observed the improved organoleptic and biological activity (antioxidant). Thus the method confirms a simple, inexpensive and eco-friendly process in obtaining pure steviosides.展开更多
Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs ...Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.展开更多
Herein, we report visible light active mesoporous cadmium bismuth niobate(CBN) nanospheres as a photocatalyst for hydrogen(H) generation from copious hydrogen sulfide(HS). CBN has been synthesized by solid state...Herein, we report visible light active mesoporous cadmium bismuth niobate(CBN) nanospheres as a photocatalyst for hydrogen(H) generation from copious hydrogen sulfide(HS). CBN has been synthesized by solid state reaction(SSR) and also using combustion method(CM) at relatively lower temperatures.The as-synthesized materials were characterized using different techniques. X-ray diffraction analysis shows the formation of single phase orthorhombic CBN. Field emission scanning electron microscopy and high resolution-transmission electron microscopy showed the particle size in the range of.5–1 μm for CBN obtained by SSR and 50–70 nm size nanospheres using CM, respectively. Interestingly, nanospheres of size 50–70 nm self assembled with 5–7 nm nanoparticles were observed in case of CBN prepared by CM.The optical properties were studied using UV–visible diffuse reflectance spectroscopy and showed band gap around.0 eV for SSR and 3.1 eV for CM. The slight shift in band gap of CM is due to nanocrystalline nature of material. Considering the band gap in visible region, the photocatalytic activity of CBN for hydrogen production from HS has been performed under visible light. CBN prepared by CM has shown utmost hydrogen evolution i.e. 6912 μmol/h/0.5 g which is much higher than CBN prepared using SSR.The enhanced photocatalytic property can be attributed to the smaller particle size, crystalline nature,high surface area and mesoporous structure of CBN prepared by combustion method. The catalyst was found to be stable, active and can be utilized for water splitting.展开更多
Today’s society is based on the use of fossil resources for transportation fuels. The result of unlimited consumption of fossil fuels is a severe depletion of the natural reserves and damage to the environment. Deple...Today’s society is based on the use of fossil resources for transportation fuels. The result of unlimited consumption of fossil fuels is a severe depletion of the natural reserves and damage to the environment. Depleting fossil reserves and increasing demand for energy together with environmental concerns have motivated researchers towards the development of alternative fuels which are eco-friendly, renewable and economical. Bioethanol is one such dominant global renewable transport biofuel which can readily substitute fossil fuels. Conventionally, bioethanol has been produced from sucrose and starch rich feedstocks (edible agricultural crops and products) known as 1st generation bioethanol;however this substrate conflicts with food and feed production. As an alternative to 1st generation bioethanol, currently there is much focus on advancing a cellulosic bioethanol concept that utilizes lignocellulosic residues from agricultural crops and residues (such as bagasse, straw, stover, stems, leaves and deoiled seed residues). Efficient conversion of lignocellulosic biomass into bioethanol remains an area of active research in terms of pretreatment of the biomass to fractionate its constituents (cellulose, hemicellulose and lignin), breakdown of cellulose and hemicellulose into hexose and pentose sugars and co-fermentation of the sugars to ethanol. The present review discusses research progress in bioethanol production from sucrose, starch and cellulosic feedstocks. Development of efficient technology to convert lignocellulosic biomass into fermentable sugars and optimization of enzymatic hydrolysis using on-site/ in-house enzyme preparation are the key areas of development in lignocellulosic bioethanol production. Moreover, finding efficient fermenting microorganisms which can utilize pentose and hexose sugars in their metabolism to produce ethanol together with minimum foam and glycerol formation is also an important parameter in fermentation. Research has been focusing on the application of genetically modified strains, thermoanaerobes and mixed cultures of different strains in bioethanol production from sucrose, starch and lignocellulosic feedstocks.展开更多
Objective:To investigate the elemental composition of the leaves and flowers of Catharanthus roseus(C.roseus) due to the plant's wide application in the indigenous medicinal system and its chemical constituents...Objective:To investigate the elemental composition of the leaves and flowers of Catharanthus roseus(C.roseus) due to the plant's wide application in the indigenous medicinal system and its chemical constituents' importance.Methods:The atomic absorption spectrophotometer was used for quantitative analysis of various elements.Results:Total 13 important elements were analyzed in leaves and flowers of C.roseus.Results indicated the presence of Na,K,Ca,Mg,Cr,Fe,Zn,Al,Cu,Ni,Pb,Cd and Mn in both leaves and flowers.The most important finding of the work was that,leaves of C.roseus showed high concentration of all elements except K and Zn while flowers of C.roseus showed higher concentration of K and Zn.Conclusions:The elemental composition in both leaves and flowers of C.roseus were found to be different.Therefore,different parts of this medicinal plant are enriched in some micro and macro nutrients like Fe,Ca,Na,K,Zn,which are very important for biological metabolic system as well as human health.展开更多
The various parts of Cudappah Igneous Provice(CIP)/Prakasham Alkaline Province(PAP)of the Eastern Dharwar Craton(EDC),southern India is known for the occurrence of lamprophyre.Present paper reports a
基金supported by the National Natural Science Foundation of China(51502078)the Major Project of Science and Technology,Education Department of Henan Province(19A150019 and 19A150018)+2 种基金the Science and Technology Research Project of Henan Province(192102310490 and 182102410090)the program for Science&Technology Innovation Team in Universities of Henan Province(19IRTSTHN029)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,and Biosciences Division,Catalysis Science program。
文摘In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.
文摘Conversion of rice straw (RS) as one of agricultural plant wastes (about 45% of the volume of rice production) to valuable industrial product was achieved, by grafting different amounts of dimethylaminoethyl methacrylate (DMAEM) on it using potassium permanganate/nitric acid redox system. This was done to obtain six levels of poly (DMAEM)—rice straw graft copolymers (PDMAEMRS) having different graft yields (expressed as N%) with increasing order and designated as (PDMAEMRS 1 to PDMAEMRS 6). The latter copolymers were dispersed in aqueous solution of heavy metal ions Cu (II) ions and filtered to form rice straw co-polymer—metal ions complex. Different factors affecting the heavy metal ions removal such as pH, extent of grafting, treatment time and rice straw dose were studied in detail. It was found from the obtained results that;the residual metal ions removal from their aqueous solutions increased with 1) increasing the extent of grafting of PDMAEMRS i.e. from PDMAEMRS 1 to PDMAEMRS 6;2) increasing the pH of the metal ions solution complex from 1 to 8;3) increasing the rice straw dosage from 0.50 to 2.0 g, then leveled off thereafter;4) increasing the time of the reaction up to 20 minute then leveled off after that. On the other hand, Pb (II), Cd (II) and Hg (II) ions were also removed from their solutions with different extent. Furthermore, the prepared co-polymer could be recovered by washing the metal ions from the complex with weak acid 1 N HNO3 (pH 2) and the metal-binding activity of the rice straw was slightly reduced by this process. Finally, the ability of PDMAEMRS to remove three types of acid dyes from their solutions was also reported.
基金the US Department of Energy’s(DOE’s)Office of Energy Efficiency and Renewable Energy,Vehicle Technology Office,Powertrain Materials Core and Light Metals Core ProgramsSample characterization is also partially supported by the Technology Commercialization Fund Fiscal Year 2020 of DOE’s Office of Technology Transitionsby the Creative Materials Discovery Program through the National Research Foundation of Korea,with computational modeling of amorphous carbons funded by the Ministry of Science,ICT and Future Planning(NRF-2016M3D1A1919181)。
文摘Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structure with the top MgCO_(3)/MgO-intermixed particulates pillars and the bottom dense layer.The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules,plasma-active CO_(2) molecules,and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer.The resulting surfaces after CO_(2)-AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion.For the hydrophobic surfaces of CO_(2)-AP treated Mg,molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source.The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment,generation of by-product,and supply of raw material.
基金Supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP)GTL Technology Development Consortium (Korean National Oil Corp., Korea Gas Corp., Daelim Industrial Co. and Hyundai Engineering Co.) under "Energy Efficiency & Resources Programs" of the Ministry of Knowledge Economy, Republic of Korea
文摘Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.
文摘We explored the possibility of using ionic liquids (ILs) as medium for efficient extraction of agarose via dissolution of red algae under varying conditions of heating or microwave irradiation. As compared to conventional methods, a very high extraction yield of good quality agarose (as high as 39 wt%) could be achieved depending upon the nature of used IL and applied experimental conditions. Purity of extracted agarose was confirmed from various spectral and analytical techniques, such as 1H and 13C NMR, FTIR, circular dichroism (CD), gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The physicochemical properties, such as gelling or melting temperature, viscosity and gel strength of extracted agarose hydrogels have been measured and compared with the agarose obtained from similar source reported in the literature. ILs were recovered after the extraction of agarose and were reused for further extraction experiments. % Recycling and extraction ability of recycled ILs in different cycles have been measured. The developed extraction process of utilizing ILs as medium is easy, simple and highly efficient as compared to the conventional methods of agarose extraction from algae.
基金the support of the Research Program for Agricultural Science & Technology Development (PJ010896)the National Academy of Agricultural Science, Rural Development Administration, Republic of Korea
文摘Research on the occurrence of perfluorochemicals (PFCs) such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the agricultural environment is lacking, in spite of their potential risk via food chain transfer from aquatic and soil-plant systems to animals and/or humans. In the present study, for the first time, soil and water samples collected from 243 different agricultural sites adjacent to waste water treatment plants (WWTPs) belonging to 81 cities and 5 provinces with different levels of industrialization in South Korea were monitored for concentrations of PFOS and PFOA by use of solid phase extraction and liquid chromatography-tandem mass spectroscopy (LC-MS/MS). Significant mean concentrations of PFOA (0.001-0.007 tJg L-1 water and 〈0.05-1.573 tJg kg-1 soil) and PFOS (0.001-0.22 tJg L-1 water and 〈0.05-0.741 pg kg-1 soil) were found in all samples. Concentrations of PFCs in soils were high, highlighting that soil is an important sink for PFCs in the agricultural environment. Samples from near WWTPs in Gyeongsang Province contained the highest concentrations of PFOS and PFOA, reflecting the concentration of heavy industry in the province. The concentrations of PFCs in agricultural water (most samples 〈0.05 pg L-~) and soils (most samples 〈1 IJg kg-~) from South Korea were less than acceptable guideline values, indicating that South Korea is not a hotspot of PFOS and PFOA contamination and that there is negligible risk to human and ecological health from these chemicals. However, further studies investigating the seasonal variation in PFOA, PFOS and other perfluorochemical concentrations in the agricultural environment are needed.
基金sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy)
文摘Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and evaluation of electrochemical performance in prototype 1.5 Ah pouch cells.Thick LiNi0.5Mn0.3Co0.2O2(NMC532)composite electrodes with an areal loading of 25 mg cm^-2(~4 mAh cm^-2)are successfully cured at a line speed of 500 feet per minute at 275 keV.Compared to the NMC532 cathode processed via a conventional coating method,the electron beam cured electrodes show higher capacity fade in the first 100 cycles,but similar fade rate afterwards.Further improvement strategies are proposed and discussed.This work demonstrates that electron beam curing is a promising method for manufacturing thick battery electrodes at high speeds and low capital/operation cost.
基金supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle,LLC, for the U. S. Department of Energy (GMV). TEM studies were performed through Oak Ridge National Laboratory’s Center for Nanophase Materials Science (CNMS) which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy
文摘Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst (SC) despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.
文摘Protective coatings are essential for superalloys to serve as blades of gas turbines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high temperature oxidation law of aluminide coatings.
文摘An important way to address global food security is to make better use of the food already produced. Since at least one third of global food is wasted before consumption, there are enormous incentives to cut this waste and create a more sustainable food system. This paper focuses upon saving food loss at the supermarket level in the US and channeling this food stream in new and efficient ways to those in hunger. A more comprehensive Food System-Sensitive Methodology has been used to pilot and evaluate a surplus food management program that diverts culled fresh fruits and vegetables from grocery stores that would otherwise be disposed of in landfills. Instead, produce is processed for donation or for new businesses. Nearly 35,000 pounds of produce was culled from a grocery store chain in Philadelphia. Twenty-five percent of this was not suitable for culinary uses, ten percent consisted of relatively small quantities of food that did not warrant further research, and about 33 percent is suitable for use at area food shelters and pantries. An experimental sample taken from the remaining 15,000 pounds was used for recipe research and development for diversion to new commercial enterprises. We analyzed a scenario where a supermarket receives $0.25 per pound for culled produce, generating about $8700 dollars in average monthly revenue while eliminating disposal costs. New commercial possibilities for the unused food were then explored. The scenario included community-based enterprises that could process the produce into value-added products that could be wholesaled back to the store at sufficient profits to support 2 - 4 community employees. Extrapolating these results to the approximately 38,000 large supermarkets in the United States suggests that much of the 1,100,000,000 pounds of produce that is currently sent to landfills can be repurposed. If diverted to new foods each of the 46.1 million SNAP recipients could figuratively receive an equivalent of 24 pounds of fruit and vegetable products per annum. This initial analysis suggests that repurposing surplus produce from supermarket discards can have significant beneficial outcomes for new food markets and the environment.
文摘In recent years there has been increasing demand for natural non-nutritive high intensity sweeteners with low-calorie value as an alternative to sucrose. Extracts of the leaves of Stevia rebaudiana (Bertoni), have been known for their sweet taste. Steviosides and rebaudioside-A are the two major diterpenoid glucosides components present in the leaf extracts of the stevia, these glycosides are 300 times sweeter than sugar and also exhibits wide therapeutic activity. The conventional methods of isolation of steviosides involve long extraction and purification procedures;therefore optimization of product yields is a challenging problem. The present study, establishes a new improvised process of extraction of steviosides from the stevia leaves in which the dry treated leaves were grounded, defatted, and extracted through pressurized hot water extractor (PHWE), followed by purification and concentration of the sweet glycosides through ultra (UF) and nano (NF) membrane filtration in obtaining high (98.2%) purity steviosides. This process established “green” method for isolation of high quality steviol glycosides, with improved final yield is 10.1% from 11% of crude leaf extract and observed the improved organoleptic and biological activity (antioxidant). Thus the method confirms a simple, inexpensive and eco-friendly process in obtaining pure steviosides.
基金the Young Thousand Talented Program and the National Natural Science Foundation of China (21671073 and 21621001)the “111” Project of the Ministry of Education of China (B17020)Program for JLU Science and Technology Innovative Research Team
文摘Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.
基金Department of Electronics and Information Technology(Deit Y),Government of India for financial supportB.P.H.E Society's Ahmednagar College Ahmednagar for financial supportNanocrystalline Materials Group C-MET for the kind support
文摘Herein, we report visible light active mesoporous cadmium bismuth niobate(CBN) nanospheres as a photocatalyst for hydrogen(H) generation from copious hydrogen sulfide(HS). CBN has been synthesized by solid state reaction(SSR) and also using combustion method(CM) at relatively lower temperatures.The as-synthesized materials were characterized using different techniques. X-ray diffraction analysis shows the formation of single phase orthorhombic CBN. Field emission scanning electron microscopy and high resolution-transmission electron microscopy showed the particle size in the range of.5–1 μm for CBN obtained by SSR and 50–70 nm size nanospheres using CM, respectively. Interestingly, nanospheres of size 50–70 nm self assembled with 5–7 nm nanoparticles were observed in case of CBN prepared by CM.The optical properties were studied using UV–visible diffuse reflectance spectroscopy and showed band gap around.0 eV for SSR and 3.1 eV for CM. The slight shift in band gap of CM is due to nanocrystalline nature of material. Considering the band gap in visible region, the photocatalytic activity of CBN for hydrogen production from HS has been performed under visible light. CBN prepared by CM has shown utmost hydrogen evolution i.e. 6912 μmol/h/0.5 g which is much higher than CBN prepared using SSR.The enhanced photocatalytic property can be attributed to the smaller particle size, crystalline nature,high surface area and mesoporous structure of CBN prepared by combustion method. The catalyst was found to be stable, active and can be utilized for water splitting.
文摘Today’s society is based on the use of fossil resources for transportation fuels. The result of unlimited consumption of fossil fuels is a severe depletion of the natural reserves and damage to the environment. Depleting fossil reserves and increasing demand for energy together with environmental concerns have motivated researchers towards the development of alternative fuels which are eco-friendly, renewable and economical. Bioethanol is one such dominant global renewable transport biofuel which can readily substitute fossil fuels. Conventionally, bioethanol has been produced from sucrose and starch rich feedstocks (edible agricultural crops and products) known as 1st generation bioethanol;however this substrate conflicts with food and feed production. As an alternative to 1st generation bioethanol, currently there is much focus on advancing a cellulosic bioethanol concept that utilizes lignocellulosic residues from agricultural crops and residues (such as bagasse, straw, stover, stems, leaves and deoiled seed residues). Efficient conversion of lignocellulosic biomass into bioethanol remains an area of active research in terms of pretreatment of the biomass to fractionate its constituents (cellulose, hemicellulose and lignin), breakdown of cellulose and hemicellulose into hexose and pentose sugars and co-fermentation of the sugars to ethanol. The present review discusses research progress in bioethanol production from sucrose, starch and cellulosic feedstocks. Development of efficient technology to convert lignocellulosic biomass into fermentable sugars and optimization of enzymatic hydrolysis using on-site/ in-house enzyme preparation are the key areas of development in lignocellulosic bioethanol production. Moreover, finding efficient fermenting microorganisms which can utilize pentose and hexose sugars in their metabolism to produce ethanol together with minimum foam and glycerol formation is also an important parameter in fermentation. Research has been focusing on the application of genetically modified strains, thermoanaerobes and mixed cultures of different strains in bioethanol production from sucrose, starch and lignocellulosic feedstocks.
基金supported by Bangladesh Council of Scientific and Industrial Research
文摘Objective:To investigate the elemental composition of the leaves and flowers of Catharanthus roseus(C.roseus) due to the plant's wide application in the indigenous medicinal system and its chemical constituents' importance.Methods:The atomic absorption spectrophotometer was used for quantitative analysis of various elements.Results:Total 13 important elements were analyzed in leaves and flowers of C.roseus.Results indicated the presence of Na,K,Ca,Mg,Cr,Fe,Zn,Al,Cu,Ni,Pb,Cd and Mn in both leaves and flowers.The most important finding of the work was that,leaves of C.roseus showed high concentration of all elements except K and Zn while flowers of C.roseus showed higher concentration of K and Zn.Conclusions:The elemental composition in both leaves and flowers of C.roseus were found to be different.Therefore,different parts of this medicinal plant are enriched in some micro and macro nutrients like Fe,Ca,Na,K,Zn,which are very important for biological metabolic system as well as human health.
文摘The various parts of Cudappah Igneous Provice(CIP)/Prakasham Alkaline Province(PAP)of the Eastern Dharwar Craton(EDC),southern India is known for the occurrence of lamprophyre.Present paper reports a