Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a c...Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a coal processing plant in Jinsha County of Guizhou Province,southwest China,was used as the research object.The content,modes of occurrence,and extraction(acid leaching after pretreatment of selective grinding,tailings discarding,and alkali roasting)of REY from the sample were analyzed.The result shows that the content of REY(1038.26μg/g)in pyrite and quartz is low but mainly enriched in kaolinite.Under the following conditions of a filling ratio of 40%(grinding media steel ball)and grinding time of 8 min,selective grinding pretreatment is applied to achieve 176.95μg/g(yield 24.08%)and 1104.93μg/g(yield 75.92%)of REY in+2 mm and-2 mm fractions,respectively.Thus,the-2 mm coal gangue fraction is selected,used as the feed,and roasted and leached with HCl.When Na_(2)CO_(3)and NaCl are separately used as roasting activators,the REY leaching ratios are 91.41%and 68.88%,respectively,under the optimum conditions.The contents of REY in the final leachate are 1010.02 and 761.08μg/g when Na_(2)CO_(3)and NaCl are used,respectively.The two REY contents are relatively higher than the impurity ions in the leachate,which facilitates further REY separation.The mechanism study reveals that high-temperature roasting increases the pore size and the total pore area of the gangue,which promotes leachate penetration and improves reaction efficiency.In addition,roasting facilitates the reaction between the sodium salt activator and kaolinite and other aluminosilicate minerals in the coal gangue to generate soluble salts,thus releasing REY into the solution.The appropriate roasting temperature transforms the activator into a molten state.Thus,the reaction between coal gangue and activator is a solid-liquid reaction rather than a solid-solid reaction,which improves the efficiency of the chemical reaction.展开更多
The aim of the experiment was to explore the feasibility of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens. 100 g/kg, 200 g/kg, 300 g/kg of discarded nutrient medium of Cordy...The aim of the experiment was to explore the feasibility of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens. 100 g/kg, 200 g/kg, 300 g/kg of discarded nutrient medium of Cordyceps militaris were added to the basal diet of laying hens. The results showed that the optimal addition of discarded nutrient medium of Cordyceps militaris in the diet of laying hens was 10%. According to the results of measuring the conventional indicators of eggs, the weight of eggs produced by laying hens fed with discarded nutrient medium of Cordyceps militaris was higher than that of laying hens fed with ordinary laying hens. The content of interleukin-1(IL-1) in the experimental group was significantly higher than that in the control group, and the concentration of IL-1 increased by 141.5 pg/mL, which indicated that the application of discarded nutrient medium of Cordyceps militaris effectively improved the immunity of laying hens. The high-throughput analysis of the intestinal contents of the two groups of laying hens showed that the microbial population abundance of the intestinal tract of the experimental group was greater than that of control group, and the application of discarded nutrient medium of Cordyceps militaris increased the diversity of bacteria in the intestinal tract of laying hens. In addition, the sensitivity of some pathogenic bacteria in the intestinal tract of chickens to drugs was also increased, thereby reducing the use of antibiotics. The secondary utilization of discarded nutrient medium of Cordyceps militaris has great development and utilization prospects, which provided a scientific reference and basic theoretical basis for the development of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens.展开更多
AIM: To assess the risk of failing to detect diminutive and small colorectal cancers with the "resect and discard" policy.METHODS: Patients who received colonoscopy and polypectomy were recruited in the retr...AIM: To assess the risk of failing to detect diminutive and small colorectal cancers with the "resect and discard" policy.METHODS: Patients who received colonoscopy and polypectomy were recruited in the retrospective study. Probable histology of the polyps was predicted by six colonoscopists by the use of NICE classification. The incidence of diminutive and small colorectal cancersand their endoscopic features were assessed. RESULTS: In total, we found 681 cases of diminutive(1-5 mm) lesions in 402 patients and 197 cases of small(6-9 mm) lesions in 151 patients. Based on pathology of the diminutive and small polyps, 105 and 18 were non-neoplastic polyps, 557 and 154 were low-grade adenomas, 18 and 24 were high-grade adenomas or intramucosal/submucosal(SM) scanty invasive carcinomas, 1 and 1 were SM deeply invasive carcinoma, respectively. The endoscopic features of invasive cancer were classified as NICE type 3 endoscopically.CONCLUSION: The risk of failing to detect diminutive and small colorectal invasive cancer with the "resect and discard" strategy might be avoided through the use of narrow-band imaging observation with the NICE classification scheme and magnifying endoscopy.展开更多
A mutualistic relationship between grasses, coal-degrading fungi, and arbuscular mycorrhizal fungi was pro- posed to account for the phyto-biodegradation of coal discard. In this study pot trial experiments were carri...A mutualistic relationship between grasses, coal-degrading fungi, and arbuscular mycorrhizal fungi was pro- posed to account for the phyto-biodegradation of coal discard. In this study pot trial experiments were carried out to confirm transformation of the carbonaceous substrate, in the presence of a suite of coal degrading fungi and arbuscular mycorrhizal fungi, into a humic-enriched soil-like material in the Cynodon dactylon/coal rhizosphere. The results show that after 47 weeks of C. dactylon growth on coal discard the concentration of humics increased from （62.9 -4- 1.5） to （112.1 ＋ 5.4） mg/kg. Substrate humic acid-like substance concentration positively correlated （r2 = 0.95） with accumu- lation of above ground C. dactylon biomass. FTIR spectroscopy of the extracted humic-like substances confirmed both product identity and increased oxidation of the coal discard substrate. Substrate ash content and electrical conductivity declined coincident with an increase in humic acid-like substance concentration, which together reduced the intensity of acidity in the C. dactylon/coal discard rhizosphere. These observations support the proposal that biological oxidative degradation of coal discard leads to increased humic-like substance concentration and formation of a soil-like material. Results have profound implications for use of coal discard as an organic substrate to replace topsoil in phyto-bioreme- diation strategies for sustainable large-scale rehabilitation of coal discard dumps.展开更多
Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous ...Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous activated carbon with large surface area synthesized from discard coal were investigated. Discard coals are waste material generated from coal beneficiation process. In developing the activated carbon, chemical activation route with the use of KOH reagent was applied. The effects of KOH/discard coal weight ratio (1:1, 2.5:1, 4:1), temperature (400-800 ℃) and particle size (0.15-0.25 mm, 0.25-0.5 mm, 0.5-1 mm) on the adsorptive properties of the activated carbon were methodically evaluated and optimized using response surface methodology. The synthesized activated carbon was characterized using BET, SEM/EDS, and XRD. The results showed that for each activation process, the surface area and pore volume of the resulting activated carbon increased with increased temperature and KOH/discard coal weight ratio. The maximum surface area of 1826.41 m2/g, pore volume of 1.252 cm^3/g and pore size of 2.77 nm were obtained at carbonization temperature of 800 ℃ and KOH/discard coal weight ratio of 4:1. Methane and nitrogen adsorption data at high pressure were fitted to Toth isotherm model with a predictive accuracy of about 99%. Adsorption parameters using the Toth model provides useful information in the design of adsorbed natural gas storage system. According to the requirements of adsorbent desired for natural gas storage, it could be stated that the synthesized activated carbon could well be applied for natural gas storage.展开更多
The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and fac...The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India. The results from the present work show that bituminous coal discard and geologically weathered coal is used by these isolates as carbon and energy source. Isolated strains and consortia colonized and degraded both coal substrates. Growth rate of the isolates is faster and stationery phase achieved sooner in minimal medium containing geologically weathered coal. This observation suggests that the oxygen-rich weathered coal is a more friable substrate and thus readily colonised and biodegraded. A reduction in mass of substrate is demonstrated for both individual isolates and consortia. The changes in pH and associated media colouration occurred concomitant with formation of humic acid-like (HS) and fulvic acid-like substances (FS) which is confirmed following analysis of these products by FT-IR spectroscopy. It is concluded that preferential metabolism of alkanes from the coal substrates provided the carbon and energy for bacterial growth and transformation of the substrates to HS and FS.展开更多
A magnetic and temperature field-coupled mathematical model is proposed to calculate the induction heating process of a discard substitution block for billet hot extrusion process. The mathematical model is validated ...A magnetic and temperature field-coupled mathematical model is proposed to calculate the induction heating process of a discard substitution block for billet hot extrusion process. The mathematical model is validated by comparing simulation results with temperature measurements recorded during physical modeling. Based on systematical analysis of calculation results, a quantitative sawtooth induction power curve was proposed to realize the aim of achieving the best distributed temperature field in the block within the shortest induction time.展开更多
The elementary and phase analysis of discarded copper ores from Yongping of China has been performed. The experi- ments of extracting copper from the discarded copper ores were done with the mixed bacteria obtained th...The elementary and phase analysis of discarded copper ores from Yongping of China has been performed. The experi- ments of extracting copper from the discarded copper ores were done with the mixed bacteria obtained through a series of enrichment, separation, domestication and combination tests. The results show that in the process of bioleaching, the pH value rises at first and drops gradually. The Eh value keeps rising along with the time and the appropriate Eh value varying between 750 and 800 mV will benefit the bioleaching copper. The high concentration of ferric ions is detrimental to the bioleaching copper. The results of bioleaching copper are good. That is, the copper recovery is 31.8% after 27 days.展开更多
On the foundation of analyzing the closed loop logistics chain of product with multi-lifecycle, the connotation of environmental value is set forth, recurring to such conceptions as supply chain and value chain. The p...On the foundation of analyzing the closed loop logistics chain of product with multi-lifecycle, the connotation of environmental value is set forth, recurring to such conceptions as supply chain and value chain. The plotting rules about disassembly tree are discussed in detail. The reachable matrix R of components’ disas- sembly is introduced into distinguishing if disassembly is needed, in combination with disassembly-deciding vector X. Furthermore, the arithmetic of disassembly cost is put forward. And the cost-benefits of components’ reusing, materials’ recycling, safety disposing are dissertated based on the activity-based costing. Then the 0-1 goal-programming model on product recovery processing is established, with components’ demotion calculated. In addition, taking the PC’s recovery processing for example, we put it into application.展开更多
Objective To investigate whether isolated blastomeres of discarded human embryos could develop into blastocysts cultured in vitro without zona pellucida. Methods Total discarded 60 embryos, which were not suitable for...Objective To investigate whether isolated blastomeres of discarded human embryos could develop into blastocysts cultured in vitro without zona pellucida. Methods Total discarded 60 embryos, which were not suitable for transplanting or freezing, were collected from 21 patients. Of 60 embryos, 10, 8, 24, 12, and 4 embryos were at 2-, 3-, 4-, 5- and 6-cell stage, respectively. These embryos were split by 0.5% protease combined with mechanical method. The resulting single blastomere was cultured individually, evaluated daily and counted blastocyst development. Pluripotency of inner cell mass （ICM） of the blastocyst was analyzed by the expression of alkaline phosphatase（AKP）. Results A total of 229 single blastomeres were isolated from 60 embryos. Defining the day when the embryos were split as the first day （d 1）. The majority of the blastomere- derived embryos followed the normal pattern of development with compaction on d 3 and cavitationon d 4 and developed into small blastocysts on d 5. Rates of division, compaction, cavity and expansion of single blastomeres from 4-cell embryos were higher than those in other groups （P 〈O.05）, and AKP was expressed in ICM. Conclusion Some of the blastomeres from discarded human embryo are flexible and able to develop into blastocysts, the potential was related to their donor embryos closely. They seem to follow development pattern of their donor embryos. The blastomere- derived blastocysts have smaller size and fewer cells compared with regular in vitro cultured human embryos. However, AKP expression showed ICM cells with pluripotency. We believe that the value of single blastomere of discarded embryos will be further confirmed in the future.展开更多
This paper aims to explore comprehensive utilization way of discarded fresh tobacco leaf. Based on modern tobacco demands on green,environmental protection and sustainable development,as well as actual situation of bi...This paper aims to explore comprehensive utilization way of discarded fresh tobacco leaf. Based on modern tobacco demands on green,environmental protection and sustainable development,as well as actual situation of biogas production facility in some villages of local tobacco area,this paper selects Longwan Village of Fengshiyan Town as the experimental site and explores the rational way of discarded fresh tobacco leaf biogas fermentation. Results show that cutting and fermentation of discarded fresh tobacco leaf before adding into biogas digester is conductive to improving p H in fermentation process,reducing crust amount,and effectively improving biogas production amount and rate. The study can provide reference for effective processing and rational utilization of discarded fresh tobacco leaf.展开更多
Background: The banning of fisheries discards by imposing an obligation to land unwanted catch constitutes a key point of the Common Fishery Policy reform proposed by the European Commission. The effect of such a ban ...Background: The banning of fisheries discards by imposing an obligation to land unwanted catch constitutes a key point of the Common Fishery Policy reform proposed by the European Commission. The effect of such a ban on discards on top marine predators such as seabirds is largely unknown, especially in oligotrophic systems of the Medi?terranean. The current study investigates the presence of scavenging seabirds around fishing trawlers as well as the exploitation of discards produced by bottom trawlers in the eastern Ionian Sea.Methods: On?board observations were randomly conducted in May and December 2014, in order to record the presence and use of fishery discards by two common seabird species, namely, Scopoli's Shearwater(Calonectris diomedea) and the Yellow?legged Gull(Larus michahellis).Results: A total of 3400 seabirds were counted during May of which 2190 individuals were Scopoli's Shearwaters and 1210 were Yellow?legged Gulls. The latter species was the only scavenger observed during winter and in total, 768 individuals were counted. Differences in species abundance in the study area are related to breeding phenology and migratory movements. The number of seabirds attending bottom trawler operations during morning and afternoon hours showed no significant differences for both seabird species. Both scavenging seabirds extensively exploited fishery discards, which were mainly demersal fish, and consumed 70–80% of the total fishery discards biomass; how?ever, they appeared to avoid poisonous species and/or large?sized fish. Yellow?legged Gulls displayed kleptoparasitic behaviour on Scopoli's Shearwater during feeding experiments. The number of such incidents depended on the number of gulls around the fishing vessel, with more than 90% success rates.Conclusions: Considering the average annual biomass of discards estimations and the consumption rate found in this work, 106.1–117.9 t may be offered as a food subsidy to scavenging seabirds in the study area and should support a substantial part of local populations. Our results constitute baseline information on the annual amount of fishery discards and their exploitation rate by seabirds in the Ionian Sea, and suggest further work for a complete understand?ing of the potential impacts of the discards reform bill on seabirds.展开更多
With the advantages of simpler structure, smaller disturbance and no self-hurt while discarding sabot, the gas-propelled amor-piercing projectile with discarding sabot (APDS) owns its promissing prospect. This paper h...With the advantages of simpler structure, smaller disturbance and no self-hurt while discarding sabot, the gas-propelled amor-piercing projectile with discarding sabot (APDS) owns its promissing prospect. This paper has studied the gas-filling and ejecting characteristics between the gas chamber iir saber and the environment. A dynamical model describing the sabot-discarding process I?as been established The authors have also given the starling condition and the parting criterion of the parting motion during the sabot-discarding. The mellon of fire gas-propelled APDS has been carefully calculated. Finally, the effect of the gashole area has been analyzed not only on the pressure in the gas chamber near the barrel exit, but also on the sabot-discarding time and distance away from the barrel.展开更多
The discarded feathers / ethylene vinyl acetate copolymer( EVA) thermoplastic composite materials was obtained with discarded feathers as reinforced material and EVA powders as matrix material by hot pressing method. ...The discarded feathers / ethylene vinyl acetate copolymer( EVA) thermoplastic composite materials was obtained with discarded feathers as reinforced material and EVA powders as matrix material by hot pressing method. Sound absorption properties were studied by changing mass ratio of discarded feathers and EVA,thickness of composite materials,hot pressing pressure and hot pressing temperature. It was found that the sound absorption properties of composite materials were good when the mass ratio of discarded feathers and EVA was 1: 1,thickness of composite materials was 30 mm,hot pressing pressure was 8 MPa,and hot pressing temperature was 80 ℃. Under the optimum conditions,the effect of composite density on sound absorption property was analyzed. In a certain range,the sound absorption property was enhanced with the decrease of the composite density.When the composite density was 0. 1g /cm^3, the maximum absorption coefficient was 0.96. Finally,the capillary theory was used to calculate the maximum sound absorption coefficient of discarded feathers / EVA thermoplastic composite materials. The good agreements of experimental results and calculated results proved the validity of the theoretical models.展开更多
Catch,bycatch and discard information is important for the assessment and management of fisheries.Using Chinese pelagic tuna longline observer data from 2010 to 2018,we studied the catch composition in the Chinese pel...Catch,bycatch and discard information is important for the assessment and management of fisheries.Using Chinese pelagic tuna longline observer data from 2010 to 2018,we studied the catch composition in the Chinese pelagic tuna longline fisheries in Atlantic targeting bigeye tuna(Thunnus obesus)and bluefin tuna(Thunnus thynnus),and analyzed the survival status and discard rates of common bycatch species.A total of 55 species,including tunas,billfishes,sharks,sea turtles,cetaceans,seabirds,and other pelagic species,were observed.The results indicated that the catch composition of the Chinese pelagic tuna longline fishery targeting bigeye tuna was significantly different from that targeting bluefin tuna.The annual discard rates of common species decreased over this period.Discard rate by length and discard mortality for common species were varied among species.This is the first study to estimate catch,bycatch,and discard using Chinese pelagic tuna longline observer data in the Atlantic Ocean,which is important for the management of Chinese tuna longline fisheries in Atlantic Ocean.展开更多
Liver transplantation is the most effective method to save the lives of patients with acute liver failure and end-stage liver disease;however,the shortage of donor livers restricts its application and is primarily ass...Liver transplantation is the most effective method to save the lives of patients with acute liver failure and end-stage liver disease;however,the shortage of donor livers restricts its application and is primarily associated with the increase in mortality of patients waiting for liver transplantation.Li et al.’s study of 15 consecutive cases showed that partial grafts with benign lesions are safe for liver transplantation(1).A study by Li et al.showed that this method was safe and feasible for children and lean individuals(2).Some studies have explored the use of discarded partial livers in open hepatectomy for benign liver tumors,such as hemangiomas,as donor livers for living liver transplantation and can alleviate the shortage of donor livers to a certain extent(3).展开更多
基金Project supported by the National Natural Science Foundation of China(51964009)。
文摘Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a coal processing plant in Jinsha County of Guizhou Province,southwest China,was used as the research object.The content,modes of occurrence,and extraction(acid leaching after pretreatment of selective grinding,tailings discarding,and alkali roasting)of REY from the sample were analyzed.The result shows that the content of REY(1038.26μg/g)in pyrite and quartz is low but mainly enriched in kaolinite.Under the following conditions of a filling ratio of 40%(grinding media steel ball)and grinding time of 8 min,selective grinding pretreatment is applied to achieve 176.95μg/g(yield 24.08%)and 1104.93μg/g(yield 75.92%)of REY in+2 mm and-2 mm fractions,respectively.Thus,the-2 mm coal gangue fraction is selected,used as the feed,and roasted and leached with HCl.When Na_(2)CO_(3)and NaCl are separately used as roasting activators,the REY leaching ratios are 91.41%and 68.88%,respectively,under the optimum conditions.The contents of REY in the final leachate are 1010.02 and 761.08μg/g when Na_(2)CO_(3)and NaCl are used,respectively.The two REY contents are relatively higher than the impurity ions in the leachate,which facilitates further REY separation.The mechanism study reveals that high-temperature roasting increases the pore size and the total pore area of the gangue,which promotes leachate penetration and improves reaction efficiency.In addition,roasting facilitates the reaction between the sodium salt activator and kaolinite and other aluminosilicate minerals in the coal gangue to generate soluble salts,thus releasing REY into the solution.The appropriate roasting temperature transforms the activator into a molten state.Thus,the reaction between coal gangue and activator is a solid-liquid reaction rather than a solid-solid reaction,which improves the efficiency of the chemical reaction.
基金Project supported by Key Project of Education Department of Liaoning Province(LJKZZ20220116)Surface Project of Science and Technology Department of Liaoning Province(2023-MS-251).
文摘The aim of the experiment was to explore the feasibility of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens. 100 g/kg, 200 g/kg, 300 g/kg of discarded nutrient medium of Cordyceps militaris were added to the basal diet of laying hens. The results showed that the optimal addition of discarded nutrient medium of Cordyceps militaris in the diet of laying hens was 10%. According to the results of measuring the conventional indicators of eggs, the weight of eggs produced by laying hens fed with discarded nutrient medium of Cordyceps militaris was higher than that of laying hens fed with ordinary laying hens. The content of interleukin-1(IL-1) in the experimental group was significantly higher than that in the control group, and the concentration of IL-1 increased by 141.5 pg/mL, which indicated that the application of discarded nutrient medium of Cordyceps militaris effectively improved the immunity of laying hens. The high-throughput analysis of the intestinal contents of the two groups of laying hens showed that the microbial population abundance of the intestinal tract of the experimental group was greater than that of control group, and the application of discarded nutrient medium of Cordyceps militaris increased the diversity of bacteria in the intestinal tract of laying hens. In addition, the sensitivity of some pathogenic bacteria in the intestinal tract of chickens to drugs was also increased, thereby reducing the use of antibiotics. The secondary utilization of discarded nutrient medium of Cordyceps militaris has great development and utilization prospects, which provided a scientific reference and basic theoretical basis for the development of discarded nutrient medium of Cordyceps militaris as feed in the production of laying hens.
基金Supported by Institute of Minimally Invasive Endoscopic Care(iM EC),Sano Hospital,No.2014-02
文摘AIM: To assess the risk of failing to detect diminutive and small colorectal cancers with the "resect and discard" policy.METHODS: Patients who received colonoscopy and polypectomy were recruited in the retrospective study. Probable histology of the polyps was predicted by six colonoscopists by the use of NICE classification. The incidence of diminutive and small colorectal cancersand their endoscopic features were assessed. RESULTS: In total, we found 681 cases of diminutive(1-5 mm) lesions in 402 patients and 197 cases of small(6-9 mm) lesions in 151 patients. Based on pathology of the diminutive and small polyps, 105 and 18 were non-neoplastic polyps, 557 and 154 were low-grade adenomas, 18 and 24 were high-grade adenomas or intramucosal/submucosal(SM) scanty invasive carcinomas, 1 and 1 were SM deeply invasive carcinoma, respectively. The endoscopic features of invasive cancer were classified as NICE type 3 endoscopically.CONCLUSION: The risk of failing to detect diminutive and small colorectal invasive cancer with the "resect and discard" strategy might be avoided through the use of narrow-band imaging observation with the NICE classification scheme and magnifying endoscopy.
文摘A mutualistic relationship between grasses, coal-degrading fungi, and arbuscular mycorrhizal fungi was pro- posed to account for the phyto-biodegradation of coal discard. In this study pot trial experiments were carried out to confirm transformation of the carbonaceous substrate, in the presence of a suite of coal degrading fungi and arbuscular mycorrhizal fungi, into a humic-enriched soil-like material in the Cynodon dactylon/coal rhizosphere. The results show that after 47 weeks of C. dactylon growth on coal discard the concentration of humics increased from （62.9 -4- 1.5） to （112.1 ＋ 5.4） mg/kg. Substrate humic acid-like substance concentration positively correlated （r2 = 0.95） with accumu- lation of above ground C. dactylon biomass. FTIR spectroscopy of the extracted humic-like substances confirmed both product identity and increased oxidation of the coal discard substrate. Substrate ash content and electrical conductivity declined coincident with an increase in humic acid-like substance concentration, which together reduced the intensity of acidity in the C. dactylon/coal discard rhizosphere. These observations support the proposal that biological oxidative degradation of coal discard leads to increased humic-like substance concentration and formation of a soil-like material. Results have profound implications for use of coal discard as an organic substrate to replace topsoil in phyto-bioreme- diation strategies for sustainable large-scale rehabilitation of coal discard dumps.
文摘Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous activated carbon with large surface area synthesized from discard coal were investigated. Discard coals are waste material generated from coal beneficiation process. In developing the activated carbon, chemical activation route with the use of KOH reagent was applied. The effects of KOH/discard coal weight ratio (1:1, 2.5:1, 4:1), temperature (400-800 ℃) and particle size (0.15-0.25 mm, 0.25-0.5 mm, 0.5-1 mm) on the adsorptive properties of the activated carbon were methodically evaluated and optimized using response surface methodology. The synthesized activated carbon was characterized using BET, SEM/EDS, and XRD. The results showed that for each activation process, the surface area and pore volume of the resulting activated carbon increased with increased temperature and KOH/discard coal weight ratio. The maximum surface area of 1826.41 m2/g, pore volume of 1.252 cm^3/g and pore size of 2.77 nm were obtained at carbonization temperature of 800 ℃ and KOH/discard coal weight ratio of 4:1. Methane and nitrogen adsorption data at high pressure were fitted to Toth isotherm model with a predictive accuracy of about 99%. Adsorption parameters using the Toth model provides useful information in the design of adsorbed natural gas storage system. According to the requirements of adsorbent desired for natural gas storage, it could be stated that the synthesized activated carbon could well be applied for natural gas storage.
基金Anglo American Thermal Coal,South Africa and the National Research Foundation,South Africa(IFR1202220169,Grant No.80879)are acknowledged for financial support.Oghenekume G.Edeki and Jacob T.Olawale acknowledge financial support in the form of doctoral bursaries from Anglo American Thermal Coal and the Technology for Human Resources for Industry Programme(THRIP,TP13070820781,UID 90252).
文摘The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India. The results from the present work show that bituminous coal discard and geologically weathered coal is used by these isolates as carbon and energy source. Isolated strains and consortia colonized and degraded both coal substrates. Growth rate of the isolates is faster and stationery phase achieved sooner in minimal medium containing geologically weathered coal. This observation suggests that the oxygen-rich weathered coal is a more friable substrate and thus readily colonised and biodegraded. A reduction in mass of substrate is demonstrated for both individual isolates and consortia. The changes in pH and associated media colouration occurred concomitant with formation of humic acid-like (HS) and fulvic acid-like substances (FS) which is confirmed following analysis of these products by FT-IR spectroscopy. It is concluded that preferential metabolism of alkanes from the coal substrates provided the carbon and energy for bacterial growth and transformation of the substrates to HS and FS.
基金financially supported by National Science Foundation of China ( NO. 51274137 and NO. 11372174)
文摘A magnetic and temperature field-coupled mathematical model is proposed to calculate the induction heating process of a discard substitution block for billet hot extrusion process. The mathematical model is validated by comparing simulation results with temperature measurements recorded during physical modeling. Based on systematical analysis of calculation results, a quantitative sawtooth induction power curve was proposed to realize the aim of achieving the best distributed temperature field in the block within the shortest induction time.
文摘The elementary and phase analysis of discarded copper ores from Yongping of China has been performed. The experi- ments of extracting copper from the discarded copper ores were done with the mixed bacteria obtained through a series of enrichment, separation, domestication and combination tests. The results show that in the process of bioleaching, the pH value rises at first and drops gradually. The Eh value keeps rising along with the time and the appropriate Eh value varying between 750 and 800 mV will benefit the bioleaching copper. The high concentration of ferric ions is detrimental to the bioleaching copper. The results of bioleaching copper are good. That is, the copper recovery is 31.8% after 27 days.
基金Supported by the National Natural Science Foundation of China(No.70472080)and Shanghai Shuguang Planning Program(No.70472080).
文摘On the foundation of analyzing the closed loop logistics chain of product with multi-lifecycle, the connotation of environmental value is set forth, recurring to such conceptions as supply chain and value chain. The plotting rules about disassembly tree are discussed in detail. The reachable matrix R of components’ disas- sembly is introduced into distinguishing if disassembly is needed, in combination with disassembly-deciding vector X. Furthermore, the arithmetic of disassembly cost is put forward. And the cost-benefits of components’ reusing, materials’ recycling, safety disposing are dissertated based on the activity-based costing. Then the 0-1 goal-programming model on product recovery processing is established, with components’ demotion calculated. In addition, taking the PC’s recovery processing for example, we put it into application.
基金supported by Grants (20060102A1022) from State 863 projectsKey projects of Science and Technology Commission of Shanghai (09ZR1419000)
文摘Objective To investigate whether isolated blastomeres of discarded human embryos could develop into blastocysts cultured in vitro without zona pellucida. Methods Total discarded 60 embryos, which were not suitable for transplanting or freezing, were collected from 21 patients. Of 60 embryos, 10, 8, 24, 12, and 4 embryos were at 2-, 3-, 4-, 5- and 6-cell stage, respectively. These embryos were split by 0.5% protease combined with mechanical method. The resulting single blastomere was cultured individually, evaluated daily and counted blastocyst development. Pluripotency of inner cell mass （ICM） of the blastocyst was analyzed by the expression of alkaline phosphatase（AKP）. Results A total of 229 single blastomeres were isolated from 60 embryos. Defining the day when the embryos were split as the first day （d 1）. The majority of the blastomere- derived embryos followed the normal pattern of development with compaction on d 3 and cavitationon d 4 and developed into small blastocysts on d 5. Rates of division, compaction, cavity and expansion of single blastomeres from 4-cell embryos were higher than those in other groups （P 〈O.05）, and AKP was expressed in ICM. Conclusion Some of the blastomeres from discarded human embryo are flexible and able to develop into blastocysts, the potential was related to their donor embryos closely. They seem to follow development pattern of their donor embryos. The blastomere- derived blastocysts have smaller size and fewer cells compared with regular in vitro cultured human embryos. However, AKP expression showed ICM cells with pluripotency. We believe that the value of single blastomere of discarded embryos will be further confirmed in the future.
文摘This paper aims to explore comprehensive utilization way of discarded fresh tobacco leaf. Based on modern tobacco demands on green,environmental protection and sustainable development,as well as actual situation of biogas production facility in some villages of local tobacco area,this paper selects Longwan Village of Fengshiyan Town as the experimental site and explores the rational way of discarded fresh tobacco leaf biogas fermentation. Results show that cutting and fermentation of discarded fresh tobacco leaf before adding into biogas digester is conductive to improving p H in fermentation process,reducing crust amount,and effectively improving biogas production amount and rate. The study can provide reference for effective processing and rational utilization of discarded fresh tobacco leaf.
基金performed within the framework of the ECODISC project,entitled“ECOsystem effect of fisheries DISCards”,partially funded by the NSRF 2007-2013 Operational Programme“Education and Lifelong Learning”,which is cofinanced by Greece and the European UnionFisheries data were collected within the framework of the 2014 Greek National Fisheries Data Collection Programme(EPSAD)funded by the Greek Government and the European Union under Regulation 199/2008/EU
文摘Background: The banning of fisheries discards by imposing an obligation to land unwanted catch constitutes a key point of the Common Fishery Policy reform proposed by the European Commission. The effect of such a ban on discards on top marine predators such as seabirds is largely unknown, especially in oligotrophic systems of the Medi?terranean. The current study investigates the presence of scavenging seabirds around fishing trawlers as well as the exploitation of discards produced by bottom trawlers in the eastern Ionian Sea.Methods: On?board observations were randomly conducted in May and December 2014, in order to record the presence and use of fishery discards by two common seabird species, namely, Scopoli's Shearwater(Calonectris diomedea) and the Yellow?legged Gull(Larus michahellis).Results: A total of 3400 seabirds were counted during May of which 2190 individuals were Scopoli's Shearwaters and 1210 were Yellow?legged Gulls. The latter species was the only scavenger observed during winter and in total, 768 individuals were counted. Differences in species abundance in the study area are related to breeding phenology and migratory movements. The number of seabirds attending bottom trawler operations during morning and afternoon hours showed no significant differences for both seabird species. Both scavenging seabirds extensively exploited fishery discards, which were mainly demersal fish, and consumed 70–80% of the total fishery discards biomass; how?ever, they appeared to avoid poisonous species and/or large?sized fish. Yellow?legged Gulls displayed kleptoparasitic behaviour on Scopoli's Shearwater during feeding experiments. The number of such incidents depended on the number of gulls around the fishing vessel, with more than 90% success rates.Conclusions: Considering the average annual biomass of discards estimations and the consumption rate found in this work, 106.1–117.9 t may be offered as a food subsidy to scavenging seabirds in the study area and should support a substantial part of local populations. Our results constitute baseline information on the annual amount of fishery discards and their exploitation rate by seabirds in the Ionian Sea, and suggest further work for a complete understand?ing of the potential impacts of the discards reform bill on seabirds.
文摘With the advantages of simpler structure, smaller disturbance and no self-hurt while discarding sabot, the gas-propelled amor-piercing projectile with discarding sabot (APDS) owns its promissing prospect. This paper has studied the gas-filling and ejecting characteristics between the gas chamber iir saber and the environment. A dynamical model describing the sabot-discarding process I?as been established The authors have also given the starling condition and the parting criterion of the parting motion during the sabot-discarding. The mellon of fire gas-propelled APDS has been carefully calculated. Finally, the effect of the gashole area has been analyzed not only on the pressure in the gas chamber near the barrel exit, but also on the sabot-discarding time and distance away from the barrel.
文摘The discarded feathers / ethylene vinyl acetate copolymer( EVA) thermoplastic composite materials was obtained with discarded feathers as reinforced material and EVA powders as matrix material by hot pressing method. Sound absorption properties were studied by changing mass ratio of discarded feathers and EVA,thickness of composite materials,hot pressing pressure and hot pressing temperature. It was found that the sound absorption properties of composite materials were good when the mass ratio of discarded feathers and EVA was 1: 1,thickness of composite materials was 30 mm,hot pressing pressure was 8 MPa,and hot pressing temperature was 80 ℃. Under the optimum conditions,the effect of composite density on sound absorption property was analyzed. In a certain range,the sound absorption property was enhanced with the decrease of the composite density.When the composite density was 0. 1g /cm^3, the maximum absorption coefficient was 0.96. Finally,the capillary theory was used to calculate the maximum sound absorption coefficient of discarded feathers / EVA thermoplastic composite materials. The good agreements of experimental results and calculated results proved the validity of the theoretical models.
文摘Catch,bycatch and discard information is important for the assessment and management of fisheries.Using Chinese pelagic tuna longline observer data from 2010 to 2018,we studied the catch composition in the Chinese pelagic tuna longline fisheries in Atlantic targeting bigeye tuna(Thunnus obesus)and bluefin tuna(Thunnus thynnus),and analyzed the survival status and discard rates of common bycatch species.A total of 55 species,including tunas,billfishes,sharks,sea turtles,cetaceans,seabirds,and other pelagic species,were observed.The results indicated that the catch composition of the Chinese pelagic tuna longline fishery targeting bigeye tuna was significantly different from that targeting bluefin tuna.The annual discard rates of common species decreased over this period.Discard rate by length and discard mortality for common species were varied among species.This is the first study to estimate catch,bycatch,and discard using Chinese pelagic tuna longline observer data in the Atlantic Ocean,which is important for the management of Chinese tuna longline fisheries in Atlantic Ocean.
基金National Natural Science Foundation of China(No.81670597).
文摘Liver transplantation is the most effective method to save the lives of patients with acute liver failure and end-stage liver disease;however,the shortage of donor livers restricts its application and is primarily associated with the increase in mortality of patients waiting for liver transplantation.Li et al.’s study of 15 consecutive cases showed that partial grafts with benign lesions are safe for liver transplantation(1).A study by Li et al.showed that this method was safe and feasible for children and lean individuals(2).Some studies have explored the use of discarded partial livers in open hepatectomy for benign liver tumors,such as hemangiomas,as donor livers for living liver transplantation and can alleviate the shortage of donor livers to a certain extent(3).
