Population development of key groups of anaerobic and aerobic bacteria involved in municipal refuse decomposition under laboratory landfill bioreactors with and without leachate recycle and inoculation was measured si...Population development of key groups of anaerobic and aerobic bacteria involved in municipal refuse decomposition under laboratory landfill bioreactors with and without leachate recycle and inoculation was measured since modeling municipal refuse was landfilled in bioreactors for about 210 days. Hydrolytic fermentative bacteria (HFB), hydrogen producing acetogenic bacteria (HPAB), methane producing bacteria (MPB), sulfate reducing bacteria (SRB), anaerobic and aerobic cellulolytic bacteria and denitrabacteria were enumerated by the most probable number technique. The results showed that the dominant microorganism groups were the methanogenic bacteria including hydrolytic fermentative, hydrogen producing acetogenic and methane producing bacteria. They were present in fresh refuse but at low values and positively affected by leachate recycle and refuse inoculation. The amounts of HFB or HPAB in digesters D4 and D5 operated with inoculation and leachate recycle reached their maximum values of 10 10 -10 12 cells/g dry refuse for HFB or 10 5-10 6 cells/g dry refuse for HPAB on day 60, in digester D3 operated with leachate recycle on day 120 for HFB (10\+9 cells/g dry refuse) or on day 90 for HPAB (10\+5 cells/g dry refuse), and in digesters D1 and D2 on day 210 for HFB (10 9 cells/g dry refuse) or on day 90 for HPAB (10 4-10 6 cells/g dry refuse). The population of methane producing bacteria in digesters D4 and D5 sharply increased on days 60 and 90 respectively, however in digesters D1, D2 and D3 on day 120. Leachate recycle and inoculation changed the cellulolytic microorganisms composition of refuse ecosystem, the higher amounts of anaerobic cellulolytic bacteria were measured in digesters D4 and D5 (10 7 cells/g dry refuse), followed by digesters D3 (10 6 cells/g dry refuse), D2 or D1(10 4 cells/g dry refuse). However, the amounts of aerobic cellulolytic bacteria were much lower than that of anaerobic cellulolytic bacteria. And it was higher in digester D3 than those in digesters D1, D2, D4 and D5 The amounts of SRB and denitrabacteria were also higher in digester D5 than those in digesters D1, D2, D3 and D4 Refuse decomposition could be accelerated by leachate recycle and inoculation in the view of microorganism development.展开更多
Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover cl...Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover clean coal with ash content of about 20% with the highest possible yield. Diesel oil as collector and pine oil as frother were used. Box-Behnken statistical design was followed for analyzing the performance at varying pulp density, collector and frother dosage. Results were discussed using 2D surface plots. Response function predictions determined by the regression analysis show coefficient of correlation(R^2) for yield and the ash content as 0.72 and 0.86, respectively. The highest yield of 45.79% is obtained at pulp density 10%, collector dose 2 kg/t and frother dose 1.5 kg/t. The lowest ash content of 18.9% is obtained at pulp density 10%, collector dose 1 kg/t and frother dose 1 kg/t.展开更多
Refuse landfill plays an important role in daily life,but also brings serious pollution.By investigating environment pollution of Beichen Shuangkou Refuse Landfill in Tianjin City,this paper put forward major problems...Refuse landfill plays an important role in daily life,but also brings serious pollution.By investigating environment pollution of Beichen Shuangkou Refuse Landfill in Tianjin City,this paper put forward major problems of this refuse landfill,and suggestions for turning it into a landscape system with regeneration and renewing capacity,so as to provide references for ecological restoration and landscaping of similar damaged land resources.展开更多
Coal refuse in a natural state is a kind of loose medium with inherent physical and chemical properties. It can be used after compaction as materials for foundation of buildings. Based on the results of numerical anal...Coal refuse in a natural state is a kind of loose medium with inherent physical and chemical properties. It can be used after compaction as materials for foundation of buildings. Based on the results of numerical analysis and experiments, a study is successfully made in this paper to reveal the compression, load-bearing and anti-mining de formation characteristics. The obtained results are of great significance in guiding the miniug operations under surface buildings erected on pre-paved refuse foundations.展开更多
In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by dr...In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by drying combustible waste and removing incombustible matter,resulting in a higher combustibility as compared to the original waste.However,the characteristics of SRFs may highly vary depending on where and from which materials they were produced.Thus,we investigated the characteristics of various SRFs using thermogravimetric analysis(TGA).As a TGA sample is commonly small,on the scale of milligrams,and,unlike homogeneous fuels,SRFs are heterogeneous,individual SRF samples analysed with this method may not represent the bulk material,and sample properties may vary significantly between batches.Therefore,we further performed combustion experiments using a small-scale combustor and sample sizes from 1 to 10 g.To optimise SRF combustor design and determine the SRF characteristics,proximate,elemental,heating value,TG,and differential thermogravimetric analyses were conducted,and weight losses and gas concentrations at different temperatures were measured upon combustion.The lower heating values of the three analysed SRFs were 20,976,16,873,and 19,762 kJ/kg,and their Cl contents were 0.89,0.95,and 1.27 wt.%(legal criterion[Cl]<2.0 wt.%).TGA and small combustor experiments showed that complete weight loss was achieved below 500°C.However,CO was detected until 620°C.展开更多
The problem of domestic refuse is becoming more and more serious with the use of all kinds of equipment in medical institutions.This matter arouses people’s attention.Traditional artificial waste classification is su...The problem of domestic refuse is becoming more and more serious with the use of all kinds of equipment in medical institutions.This matter arouses people’s attention.Traditional artificial waste classification is subjective and cannot be put accurately;moreover,the working environment of sorting is poor and the efficiency is low.Therefore,automated and effective sorting is needed.In view of the current development of deep learning,it can provide a good auxiliary role for classification and realize automatic classification.In this paper,the ResNet-50 convolutional neural network based on the transfer learning method is applied to design the image classifier to obtain the domestic refuse classification with high accuracy.By comparing the method designed in this paper with back propagation neural network and convolutional neural network,it is concluded that the CNN based on transfer learning method applied in this paper with higher accuracy rate and lower false detection rate.Further,under the shortage situation of data samples,the method with transfer learning and ResNet-50 training model is effective to improve the accuracy of image classification.展开更多
Objective: To assess the prevalence of HIV infection, to highlight HIV-testing refusal rates among participants in a population-based tuberculosis survey and to assess the implication for programme implementation.Meth...Objective: To assess the prevalence of HIV infection, to highlight HIV-testing refusal rates among participants in a population-based tuberculosis survey and to assess the implication for programme implementation.Methods: This cross-sectional study on the characteristics of participants who refused HIV testing was conducted in a national survey in Zambia. All eligible participants were aged above 15 years and included in the analysis.Results: Out of the 44 791 tuberculosis survey participants, 14 164(31.6%) refused to participate in HIV testing. The unemployed, rural dwellers, married, and those aged 15-24 years were associated with higher refusal rates.Conclusions: Strategies to improve HIV testing acceptance are necessary. Qualitative research is recommended to understand the reasons for testing refusals so that remedial interventions can be implemented.展开更多
Renal transplantation remains the most effective treatment of End Stage Renal Failure (ESRF). In this cross sectional study we explore the reasons behind refusal of renal transplantation among adults’ Sudanese haemod...Renal transplantation remains the most effective treatment of End Stage Renal Failure (ESRF). In this cross sectional study we explore the reasons behind refusal of renal transplantation among adults’ Sudanese haemodialysis patients. The subjects of the study are ESRF adults’ patients on regular haemodialysis treatment in 15 haemdoialysis centres in Khartoum/Sudan. All patients who are on regular haemodialysis were interviewed by questionnaire to explore the reasons of refusal of renal transplantation. A total of 1583 ESRF adults’ patients on regular haemodialysis have been participated in the study, 381 (24.1%) patients refused kidney transplantation. The mean age of patients refusing kidney transplantation was (58.5 + 15.1 years);77.4% of them were ≥50 years old, 59.2% were males and 88.1% were unemployed, patients older than 50 years old and unemployed are tend to refuse renal transplantation展开更多
Forced aeration is one of the promising ways to accelerate landfill reclamation,and understanding the relation between aeration rates and waste properties is the prerequisite to implementing forced aeration under the ...Forced aeration is one of the promising ways to accelerate landfill reclamation,and understanding the relation between aeration rates and waste properties is the prerequisite to implementing forced aeration under the target of energy saving and carbon reduction.In this work,landfill reclamation processes with forced aeration were simulated using aged refuses(ARs)of 1,4,7,10,and 13 disposal years,and the potential of field application was also investigated based on a field project,to identify the degradation rate of organic components,the O_(2)consumption efficiency and their correlations to microbes.It was found that the removal rate of organic matter declined from 20.3%(AR_(1))to 12.6%(AR_(13)),and that biodegradable matter(BDM)decreased from 5.2%to 2.4%at the set aeration rate of 0.12 L O_(2)/kg waste(Dry Matter,DM)/day.A linear relationship between the degradation rate constant(K)of BDM and disposal age(x)was established:K=−0.0002193x+0.0091(R^(2)=0.854),suggesting that BDM might be a suitable indicator to reflect the stabilization of ARs.The cellulose/lignin ratio decrease rate for AR1(18.3%)was much higher than that for AR13(3.1%),while the corresponding humic-acid/fulvic-acid ratio increased from 1.44 to 2.16.The dominant bacteria shifted from Corynebacterium(9.2%),Acinetobacter(6.6%),and Fermentimonas(6.5%),genes related to the decompose of biodegradable organics,to Stenotrophomonas(10.2%)and Clostridiales(3.7%),which were associated with humification.The aeration efficiencies of lab-scale tests were in the range of 5.4–11.8 g BDM/L O_(2)for ARs with disposal ages of 1–13 years,and in situ landfill reclamation,ARs with disposal ages of 10–18 years were around 1.9–8.8 g BDM/L O_(2),as the disposal age decreased.The increased discrepancy was observed in ARs at the lab-scale and field scale,indicating that the forced aeration rate should be adjusted based on ARs and the unit compartment combined,to reduce the operation cost.展开更多
To accelerate the efficiency of methane biodegradation in landfills,a Gram-negative,rod-shaped,non-motile,non-spore-forming bacterium,JTA1,which can utilize methane as well as acetate,was isolated from the Laogang MSW...To accelerate the efficiency of methane biodegradation in landfills,a Gram-negative,rod-shaped,non-motile,non-spore-forming bacterium,JTA1,which can utilize methane as well as acetate,was isolated from the Laogang MSW landfills,Shanghai,China.Strain JTA1 was a member of genus Methylocystis on the basis of 16S rRNA and pmoA gene sequence similarity.The maximum specific cell growth rates(μmax=0.042 hr-1,R2=0.995) was derived through Boltzmann simulation,and the apparent half-saturation constants(Km(app)=7.08mmol/L,R2=0.982) was calculated according to Michaelis-Menton hyperbolic model,indicating that Methylocystis strain JTA1 had higher-affinity potential for methane oxidation than other reported methanotrophs.By way of adding the strain JTA1 culture,the methane consumption of aged refuse reached 115mL,almost two times of control experiment.In addition,high tolerance of Methylocystis strain JTA1 to chloroform could facilitate the methane oxidation of aged refuse bio-covers.At the chloroform concentration of 50mg/L,the methane-oxidation rate of bio-cover reached 0.114mL/(day·g),much higher than the highest rate,0.0135mL/(day·g),of reported bio-covers.In conclusion,strain JTA1 opens up a new possibility for environmental biotechnology,such as soil or landfills bioremediation and wastewater decontamination.展开更多
Due to the increasing criticality of rare earth elements(REEs),it has become essential to recover REEs from alternative resources.In this study,systematic REEs leaching tests were performed on the calcination product ...Due to the increasing criticality of rare earth elements(REEs),it has become essential to recover REEs from alternative resources.In this study,systematic REEs leaching tests were performed on the calcination product of a coal coarse refuse using hydrochloric acid and different types of organic acid as lixiviants.Experimental results show that the recovery of REEs,especially heavy REEs(HREEs)and scandium(Sc),is improved by using selected organic acids.Citric acid and DL-malic acid afford the best leaching performances;whereas,malonic acid,oxalic acid,and DL-tartaric acid are inferior to hydrochloric acid.Results of zeta potential measurements and solution chemical equilibrium calculations show that malonic acid is more likely adsorbed on the surface of the calcined material compared with citric acid and DL-malic acid.The adsorption may reduce the effective concentration of malonic species in solution and/or increase the amount of REEs adsorbed on the surface,thereby impairing the leaching recovery.Compared with light REEs(LREEs),a stronger adsorption of the HREEs on the surface is observed from electro-kinetic test results.This finding explains why organic acids impose a more positive impact on the leaching recovery of HREEs,By complexing with the HREEs,organic acids can keep the metal ions in solution and improve the leaching recovery.The adsorption of Sc^(3+)on the surface is the lowest compared with other REEs.Therefore,rather than complexing,the organic anionic species likely play a function of solubilizing Sc from the solid,which is similar to that of hydrogen ions.展开更多
General anesthesia and Obstetric Anesthesia is the gold standard for a cesarean section but there are some cases where general anesthesia is unavoidable. The use of general anesthesia for cesarean delivery has decreas...General anesthesia and Obstetric Anesthesia is the gold standard for a cesarean section but there are some cases where general anesthesia is unavoidable. The use of general anesthesia for cesarean delivery has decreased in recent years due to the widespread use of neuraxial techniques. The choice of anesthesia techniques for cesarean delivery depends on several factors, including the patient’s psychology and the attending physician’s experience. It is chosen because of its safety profile and its benefits to the mother and fetus. It may be indicated due to emergency, maternal refusal of regional techniques, or regional contraindications. Major complications include failed intubation, gastric content aspiration, and increased bleeding risk. This study aims to evaluate the impact of a newly launched team on obstetric anesthesia practice.展开更多
THE Chinese national flag roseslowly along the post and theChinese national anthem, fullof power and grandur,filledthe air in the symposium atBangkok, Thailand. A slender,pretty young woman with an ar-tifcial leg stoo...THE Chinese national flag roseslowly along the post and theChinese national anthem, fullof power and grandur,filledthe air in the symposium atBangkok, Thailand. A slender,pretty young woman with an ar-tifcial leg stood on the plat-form, holding the gold medal-lion in front of her chest withone hand, and the national em-blem with the other. She sangloudly the Chinese national an-them together with the music,happy tears raining down hercheeks. Touched by her jubila-tion and the bloodstains on herartificial leg, the audiencecheered again and again.展开更多
Halloween may have passed but the controversy surrounding Western holidays in China has not.On November 1,a woman complained online that children at a local Family Mart had been taking candy directly f rom the shelves...Halloween may have passed but the controversy surrounding Western holidays in China has not.On November 1,a woman complained online that children at a local Family Mart had been taking candy directly f rom the shelves,and getting staff to pay for it.展开更多
AIM: To assess the feasibility, accuracy and acceptability of PillCam Colon 2 in detection of significant lesions in colorectal cancer risk patients, unable or unwilling to perform colonoscopy. METHODS: This is a pros...AIM: To assess the feasibility, accuracy and acceptability of PillCam Colon 2 in detection of significant lesions in colorectal cancer risk patients, unable or unwilling to perform colonoscopy. METHODS: This is a prospective, single center study using the second generation of PillCam Colon capsule. In all patients the readers were instructed to review the entire colon capsule endoscopy(CCE) examination using Rapid 7 software and additionally to note significant extra-colonic findings. Colonic significant findings were described according to European Society of Gastrointestinal Endoscopy guidelines. CCE procedure completion rate, level of bowel preparation and rate of adverse events were assessed. RESULTS: A total of 70 patients at risk of colorectal cancer were enrolled in the study. In three patients the procedure failed because the capsule was not functioning when entered the colon. PillCam Colon 2 showed positive findings in 23(34%, 95%CI: 21.6%-44.1%) of the remaining 67 patients. Six patients were diagnosedwith tumors: 4 with colon cancers, 1 with gastric cancer and 1 with a small bowel cancer. The capsule findings were confirmed after surgery in all these patients. The capsule excretion rate in twelve hours was 77% with 54 patients having a complete examination. The rectum was not explored during CCE procedure, in 16 patients(23%, 95%CI: 13.7%-34.1%). Every patient accepted CCE as an alternative exploration tool and 65/70(93%) agreed to have another future control by CCE. No complications were reported during or after CCE examination. CONCLUSION: PillCam Colon 2 capsule was effective in detecting significant lesions and might be considered an adequate alternative diagnostic tool in patients unable or unwilling to undergo colonoscopy.展开更多
This paper provides an overview of coal waste management practices with two case studies and an estimate of management cost in 2010 US dollars.Processing of as-mined coal typically results in considerable amount of co...This paper provides an overview of coal waste management practices with two case studies and an estimate of management cost in 2010 US dollars.Processing of as-mined coal typically results in considerable amount of coarse and fine coal processing wastes because of in-seam and out-of-seam dilution mining.Processing plant clean coal recovery values run typically 50%-80%.Trace metals and sulfur may be present in waste materials that may result in leachate water with corrosive characteristics.Water discharges may require special measures such as liner and collection systems,and treatment to neutralize acid drainage and/or water quality for trace elements.The potential for variations in coal waste production and quality depends upon mining or processing,plus the long-term methods of waste placement.The changes in waste generation rates and engineering properties of the coal waste during the life of the facility must be considered.Safe,economical and environmentally acceptable management of coal waste involves consideration of geology,soil and rock mechanics,hydrology,hydraulics,geochemistry,soil science,agronomy and environmental sciences.These support all aspects of the regulatory environment including the design and construction of earth and rock embankments and dams,as well as a wide variety of waste disposal structures.Development of impoundments is critical and require considerations of typical water-impounding dams and additional requirements of coal waste disposal impoundments.The primary purpose of a coal waste disposal facility is to dispose of unusable waste materials from mining.However,at some sites coal waste impoundments serve to provide water storage capacity for processing and flood attenuation.展开更多
Loaded on the cordierite, the rare earth doped composite catalyst was prepared by sol-gel method combined with dipping technique. Taking Orthodichlorobenzene as model, the catalyst was used to remove the dioxins of th...Loaded on the cordierite, the rare earth doped composite catalyst was prepared by sol-gel method combined with dipping technique. Taking Orthodichlorobenzene as model, the catalyst was used to remove the dioxins of the waste gas. The results showed that at 280 ℃ and gas space velocity being 8000 h-1, the orthodichlorobenzene could be removed effectivily by the prepared CeO_2-TiO2-V2O5 composite catalyst whose activity was remarkably enhanced by the doping of Ce, while the industrial side-stream test of dioxins from refuse incineration smoke indicated that the decomposition rate could reach above 93% under the same conditions.展开更多
The use of low-quality coals and flotoconcentrates is currently severely limited,and the problem of managing municipal waste from anthropogenic activities is currently a challenge.The problems of reducing carbon dioxi...The use of low-quality coals and flotoconcentrates is currently severely limited,and the problem of managing municipal waste from anthropogenic activities is currently a challenge.The problems of reducing carbon dioxide emissions,utilizing the energy potential of waste and increasing its recycling have an impact on the costs of electricity production.Considering the abundant streams of unused fuels,they can be considered as attractive energy materials,so environmentally-friendly and cost-effective options for their utilization should be developed.A study was conducted using steam co-gasification technology on selected coals,flotation concentrates and Refuse Derived Fuel(RDF)alternative fuel.Selected low-quality coals were combined with RDF alternative fuel in a process aimed at hydrogen production.The experiments produced gas with hydrogen concentrations ranging from 67%(vol.)to 68%(vol.)with low methane concentrations.It was observed that the addition of alternative fuels helped to increase the hydrogen concentration in syngas.Attention was paid to the catalytic ability of the metal oxides contained in the fuel blend,with particular reference to K_(2)O and Al_(2)O_(3)and TiO_(2).展开更多
基金TheNationalNaturalScienceFoundationofChina (No .5 980 80 12 )andZhejiangProvince (No .5 9912 7)
文摘Population development of key groups of anaerobic and aerobic bacteria involved in municipal refuse decomposition under laboratory landfill bioreactors with and without leachate recycle and inoculation was measured since modeling municipal refuse was landfilled in bioreactors for about 210 days. Hydrolytic fermentative bacteria (HFB), hydrogen producing acetogenic bacteria (HPAB), methane producing bacteria (MPB), sulfate reducing bacteria (SRB), anaerobic and aerobic cellulolytic bacteria and denitrabacteria were enumerated by the most probable number technique. The results showed that the dominant microorganism groups were the methanogenic bacteria including hydrolytic fermentative, hydrogen producing acetogenic and methane producing bacteria. They were present in fresh refuse but at low values and positively affected by leachate recycle and refuse inoculation. The amounts of HFB or HPAB in digesters D4 and D5 operated with inoculation and leachate recycle reached their maximum values of 10 10 -10 12 cells/g dry refuse for HFB or 10 5-10 6 cells/g dry refuse for HPAB on day 60, in digester D3 operated with leachate recycle on day 120 for HFB (10\+9 cells/g dry refuse) or on day 90 for HPAB (10\+5 cells/g dry refuse), and in digesters D1 and D2 on day 210 for HFB (10 9 cells/g dry refuse) or on day 90 for HPAB (10 4-10 6 cells/g dry refuse). The population of methane producing bacteria in digesters D4 and D5 sharply increased on days 60 and 90 respectively, however in digesters D1, D2 and D3 on day 120. Leachate recycle and inoculation changed the cellulolytic microorganisms composition of refuse ecosystem, the higher amounts of anaerobic cellulolytic bacteria were measured in digesters D4 and D5 (10 7 cells/g dry refuse), followed by digesters D3 (10 6 cells/g dry refuse), D2 or D1(10 4 cells/g dry refuse). However, the amounts of aerobic cellulolytic bacteria were much lower than that of anaerobic cellulolytic bacteria. And it was higher in digester D3 than those in digesters D1, D2, D4 and D5 The amounts of SRB and denitrabacteria were also higher in digester D5 than those in digesters D1, D2, D3 and D4 Refuse decomposition could be accelerated by leachate recycle and inoculation in the view of microorganism development.
文摘Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover clean coal with ash content of about 20% with the highest possible yield. Diesel oil as collector and pine oil as frother were used. Box-Behnken statistical design was followed for analyzing the performance at varying pulp density, collector and frother dosage. Results were discussed using 2D surface plots. Response function predictions determined by the regression analysis show coefficient of correlation(R^2) for yield and the ash content as 0.72 and 0.86, respectively. The highest yield of 45.79% is obtained at pulp density 10%, collector dose 2 kg/t and frother dose 1.5 kg/t. The lowest ash content of 18.9% is obtained at pulp density 10%, collector dose 1 kg/t and frother dose 1 kg/t.
文摘Refuse landfill plays an important role in daily life,but also brings serious pollution.By investigating environment pollution of Beichen Shuangkou Refuse Landfill in Tianjin City,this paper put forward major problems of this refuse landfill,and suggestions for turning it into a landscape system with regeneration and renewing capacity,so as to provide references for ecological restoration and landscaping of similar damaged land resources.
文摘Coal refuse in a natural state is a kind of loose medium with inherent physical and chemical properties. It can be used after compaction as materials for foundation of buildings. Based on the results of numerical analysis and experiments, a study is successfully made in this paper to reveal the compression, load-bearing and anti-mining de formation characteristics. The obtained results are of great significance in guiding the miniug operations under surface buildings erected on pre-paved refuse foundations.
基金supported by the Korea Environment Industry&Technology Institute(KEITI)through a Public Technology Program based on the Environmental Policy Program funded by the Korea Ministry of Environment(MOE)[Grant number:2016000710008].
文摘In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by drying combustible waste and removing incombustible matter,resulting in a higher combustibility as compared to the original waste.However,the characteristics of SRFs may highly vary depending on where and from which materials they were produced.Thus,we investigated the characteristics of various SRFs using thermogravimetric analysis(TGA).As a TGA sample is commonly small,on the scale of milligrams,and,unlike homogeneous fuels,SRFs are heterogeneous,individual SRF samples analysed with this method may not represent the bulk material,and sample properties may vary significantly between batches.Therefore,we further performed combustion experiments using a small-scale combustor and sample sizes from 1 to 10 g.To optimise SRF combustor design and determine the SRF characteristics,proximate,elemental,heating value,TG,and differential thermogravimetric analyses were conducted,and weight losses and gas concentrations at different temperatures were measured upon combustion.The lower heating values of the three analysed SRFs were 20,976,16,873,and 19,762 kJ/kg,and their Cl contents were 0.89,0.95,and 1.27 wt.%(legal criterion[Cl]<2.0 wt.%).TGA and small combustor experiments showed that complete weight loss was achieved below 500°C.However,CO was detected until 620°C.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 61806028,Grant 61672437 and Grant 61702428Sichuan Science and Technology Program under Grants 21ZDYF2484,2021YFN0104,21GJHZ0061,21ZDYF3629,21ZDYF2907,21ZDYF0418,21YYJC1827,21ZDYF3537,2019YJ0356the Chinese Scholarship Council under Grants 202008510036,201908515022.
文摘The problem of domestic refuse is becoming more and more serious with the use of all kinds of equipment in medical institutions.This matter arouses people’s attention.Traditional artificial waste classification is subjective and cannot be put accurately;moreover,the working environment of sorting is poor and the efficiency is low.Therefore,automated and effective sorting is needed.In view of the current development of deep learning,it can provide a good auxiliary role for classification and realize automatic classification.In this paper,the ResNet-50 convolutional neural network based on the transfer learning method is applied to design the image classifier to obtain the domestic refuse classification with high accuracy.By comparing the method designed in this paper with back propagation neural network and convolutional neural network,it is concluded that the CNN based on transfer learning method applied in this paper with higher accuracy rate and lower false detection rate.Further,under the shortage situation of data samples,the method with transfer learning and ResNet-50 training model is effective to improve the accuracy of image classification.
基金Supported by the government of the Republic of Zambia(GRZ) through Ministry of Health(budget support)United States Government(USG)through USAID and CDC Zambia,Grant U2GPS001792
文摘Objective: To assess the prevalence of HIV infection, to highlight HIV-testing refusal rates among participants in a population-based tuberculosis survey and to assess the implication for programme implementation.Methods: This cross-sectional study on the characteristics of participants who refused HIV testing was conducted in a national survey in Zambia. All eligible participants were aged above 15 years and included in the analysis.Results: Out of the 44 791 tuberculosis survey participants, 14 164(31.6%) refused to participate in HIV testing. The unemployed, rural dwellers, married, and those aged 15-24 years were associated with higher refusal rates.Conclusions: Strategies to improve HIV testing acceptance are necessary. Qualitative research is recommended to understand the reasons for testing refusals so that remedial interventions can be implemented.
文摘Renal transplantation remains the most effective treatment of End Stage Renal Failure (ESRF). In this cross sectional study we explore the reasons behind refusal of renal transplantation among adults’ Sudanese haemodialysis patients. The subjects of the study are ESRF adults’ patients on regular haemodialysis treatment in 15 haemdoialysis centres in Khartoum/Sudan. All patients who are on regular haemodialysis were interviewed by questionnaire to explore the reasons of refusal of renal transplantation. A total of 1583 ESRF adults’ patients on regular haemodialysis have been participated in the study, 381 (24.1%) patients refused kidney transplantation. The mean age of patients refusing kidney transplantation was (58.5 + 15.1 years);77.4% of them were ≥50 years old, 59.2% were males and 88.1% were unemployed, patients older than 50 years old and unemployed are tend to refuse renal transplantation
基金supported by the National Natural Science Foundation of China(No.42077111)the National Key Research and Development Plans of Special Project for Site soils(No.2018YFC1800601)the Social Development Science and Technology Project of Shanghai“Science and Technology Innovation Action Plan”(No.20dz1203401).
文摘Forced aeration is one of the promising ways to accelerate landfill reclamation,and understanding the relation between aeration rates and waste properties is the prerequisite to implementing forced aeration under the target of energy saving and carbon reduction.In this work,landfill reclamation processes with forced aeration were simulated using aged refuses(ARs)of 1,4,7,10,and 13 disposal years,and the potential of field application was also investigated based on a field project,to identify the degradation rate of organic components,the O_(2)consumption efficiency and their correlations to microbes.It was found that the removal rate of organic matter declined from 20.3%(AR_(1))to 12.6%(AR_(13)),and that biodegradable matter(BDM)decreased from 5.2%to 2.4%at the set aeration rate of 0.12 L O_(2)/kg waste(Dry Matter,DM)/day.A linear relationship between the degradation rate constant(K)of BDM and disposal age(x)was established:K=−0.0002193x+0.0091(R^(2)=0.854),suggesting that BDM might be a suitable indicator to reflect the stabilization of ARs.The cellulose/lignin ratio decrease rate for AR1(18.3%)was much higher than that for AR13(3.1%),while the corresponding humic-acid/fulvic-acid ratio increased from 1.44 to 2.16.The dominant bacteria shifted from Corynebacterium(9.2%),Acinetobacter(6.6%),and Fermentimonas(6.5%),genes related to the decompose of biodegradable organics,to Stenotrophomonas(10.2%)and Clostridiales(3.7%),which were associated with humification.The aeration efficiencies of lab-scale tests were in the range of 5.4–11.8 g BDM/L O_(2)for ARs with disposal ages of 1–13 years,and in situ landfill reclamation,ARs with disposal ages of 10–18 years were around 1.9–8.8 g BDM/L O_(2),as the disposal age decreased.The increased discrepancy was observed in ARs at the lab-scale and field scale,indicating that the forced aeration rate should be adjusted based on ARs and the unit compartment combined,to reduce the operation cost.
基金supported by the National Natural Science Foundation of China (No. 51008322)the Natural Science Foundation Project of Chongqing (No. CSTC 2010BB7300,5309)the State Key Laboratory of Pollution Control and Resource Reuse (No. PCRRF10001)
文摘To accelerate the efficiency of methane biodegradation in landfills,a Gram-negative,rod-shaped,non-motile,non-spore-forming bacterium,JTA1,which can utilize methane as well as acetate,was isolated from the Laogang MSW landfills,Shanghai,China.Strain JTA1 was a member of genus Methylocystis on the basis of 16S rRNA and pmoA gene sequence similarity.The maximum specific cell growth rates(μmax=0.042 hr-1,R2=0.995) was derived through Boltzmann simulation,and the apparent half-saturation constants(Km(app)=7.08mmol/L,R2=0.982) was calculated according to Michaelis-Menton hyperbolic model,indicating that Methylocystis strain JTA1 had higher-affinity potential for methane oxidation than other reported methanotrophs.By way of adding the strain JTA1 culture,the methane consumption of aged refuse reached 115mL,almost two times of control experiment.In addition,high tolerance of Methylocystis strain JTA1 to chloroform could facilitate the methane oxidation of aged refuse bio-covers.At the chloroform concentration of 50mg/L,the methane-oxidation rate of bio-cover reached 0.114mL/(day·g),much higher than the highest rate,0.0135mL/(day·g),of reported bio-covers.In conclusion,strain JTA1 opens up a new possibility for environmental biotechnology,such as soil or landfills bioremediation and wastewater decontamination.
文摘Due to the increasing criticality of rare earth elements(REEs),it has become essential to recover REEs from alternative resources.In this study,systematic REEs leaching tests were performed on the calcination product of a coal coarse refuse using hydrochloric acid and different types of organic acid as lixiviants.Experimental results show that the recovery of REEs,especially heavy REEs(HREEs)and scandium(Sc),is improved by using selected organic acids.Citric acid and DL-malic acid afford the best leaching performances;whereas,malonic acid,oxalic acid,and DL-tartaric acid are inferior to hydrochloric acid.Results of zeta potential measurements and solution chemical equilibrium calculations show that malonic acid is more likely adsorbed on the surface of the calcined material compared with citric acid and DL-malic acid.The adsorption may reduce the effective concentration of malonic species in solution and/or increase the amount of REEs adsorbed on the surface,thereby impairing the leaching recovery.Compared with light REEs(LREEs),a stronger adsorption of the HREEs on the surface is observed from electro-kinetic test results.This finding explains why organic acids impose a more positive impact on the leaching recovery of HREEs,By complexing with the HREEs,organic acids can keep the metal ions in solution and improve the leaching recovery.The adsorption of Sc^(3+)on the surface is the lowest compared with other REEs.Therefore,rather than complexing,the organic anionic species likely play a function of solubilizing Sc from the solid,which is similar to that of hydrogen ions.
文摘General anesthesia and Obstetric Anesthesia is the gold standard for a cesarean section but there are some cases where general anesthesia is unavoidable. The use of general anesthesia for cesarean delivery has decreased in recent years due to the widespread use of neuraxial techniques. The choice of anesthesia techniques for cesarean delivery depends on several factors, including the patient’s psychology and the attending physician’s experience. It is chosen because of its safety profile and its benefits to the mother and fetus. It may be indicated due to emergency, maternal refusal of regional techniques, or regional contraindications. Major complications include failed intubation, gastric content aspiration, and increased bleeding risk. This study aims to evaluate the impact of a newly launched team on obstetric anesthesia practice.
文摘THE Chinese national flag roseslowly along the post and theChinese national anthem, fullof power and grandur,filledthe air in the symposium atBangkok, Thailand. A slender,pretty young woman with an ar-tifcial leg stood on the plat-form, holding the gold medal-lion in front of her chest withone hand, and the national em-blem with the other. She sangloudly the Chinese national an-them together with the music,happy tears raining down hercheeks. Touched by her jubila-tion and the bloodstains on herartificial leg, the audiencecheered again and again.
文摘Halloween may have passed but the controversy surrounding Western holidays in China has not.On November 1,a woman complained online that children at a local Family Mart had been taking candy directly f rom the shelves,and getting staff to pay for it.
文摘AIM: To assess the feasibility, accuracy and acceptability of PillCam Colon 2 in detection of significant lesions in colorectal cancer risk patients, unable or unwilling to perform colonoscopy. METHODS: This is a prospective, single center study using the second generation of PillCam Colon capsule. In all patients the readers were instructed to review the entire colon capsule endoscopy(CCE) examination using Rapid 7 software and additionally to note significant extra-colonic findings. Colonic significant findings were described according to European Society of Gastrointestinal Endoscopy guidelines. CCE procedure completion rate, level of bowel preparation and rate of adverse events were assessed. RESULTS: A total of 70 patients at risk of colorectal cancer were enrolled in the study. In three patients the procedure failed because the capsule was not functioning when entered the colon. PillCam Colon 2 showed positive findings in 23(34%, 95%CI: 21.6%-44.1%) of the remaining 67 patients. Six patients were diagnosedwith tumors: 4 with colon cancers, 1 with gastric cancer and 1 with a small bowel cancer. The capsule findings were confirmed after surgery in all these patients. The capsule excretion rate in twelve hours was 77% with 54 patients having a complete examination. The rectum was not explored during CCE procedure, in 16 patients(23%, 95%CI: 13.7%-34.1%). Every patient accepted CCE as an alternative exploration tool and 65/70(93%) agreed to have another future control by CCE. No complications were reported during or after CCE examination. CONCLUSION: PillCam Colon 2 capsule was effective in detecting significant lesions and might be considered an adequate alternative diagnostic tool in patients unable or unwilling to undergo colonoscopy.
基金authors sincere acknowledge the funding support by the Illinois Clean Coal Institute and the Department of Commerce and Economic Opportunitythe support at the coop-erating mines for providing high quality data included in this paper
文摘This paper provides an overview of coal waste management practices with two case studies and an estimate of management cost in 2010 US dollars.Processing of as-mined coal typically results in considerable amount of coarse and fine coal processing wastes because of in-seam and out-of-seam dilution mining.Processing plant clean coal recovery values run typically 50%-80%.Trace metals and sulfur may be present in waste materials that may result in leachate water with corrosive characteristics.Water discharges may require special measures such as liner and collection systems,and treatment to neutralize acid drainage and/or water quality for trace elements.The potential for variations in coal waste production and quality depends upon mining or processing,plus the long-term methods of waste placement.The changes in waste generation rates and engineering properties of the coal waste during the life of the facility must be considered.Safe,economical and environmentally acceptable management of coal waste involves consideration of geology,soil and rock mechanics,hydrology,hydraulics,geochemistry,soil science,agronomy and environmental sciences.These support all aspects of the regulatory environment including the design and construction of earth and rock embankments and dams,as well as a wide variety of waste disposal structures.Development of impoundments is critical and require considerations of typical water-impounding dams and additional requirements of coal waste disposal impoundments.The primary purpose of a coal waste disposal facility is to dispose of unusable waste materials from mining.However,at some sites coal waste impoundments serve to provide water storage capacity for processing and flood attenuation.
基金the National Natural Science Foundation of China (50104003)
文摘Loaded on the cordierite, the rare earth doped composite catalyst was prepared by sol-gel method combined with dipping technique. Taking Orthodichlorobenzene as model, the catalyst was used to remove the dioxins of the waste gas. The results showed that at 280 ℃ and gas space velocity being 8000 h-1, the orthodichlorobenzene could be removed effectivily by the prepared CeO_2-TiO2-V2O5 composite catalyst whose activity was remarkably enhanced by the doping of Ce, while the industrial side-stream test of dioxins from refuse incineration smoke indicated that the decomposition rate could reach above 93% under the same conditions.
文摘The use of low-quality coals and flotoconcentrates is currently severely limited,and the problem of managing municipal waste from anthropogenic activities is currently a challenge.The problems of reducing carbon dioxide emissions,utilizing the energy potential of waste and increasing its recycling have an impact on the costs of electricity production.Considering the abundant streams of unused fuels,they can be considered as attractive energy materials,so environmentally-friendly and cost-effective options for their utilization should be developed.A study was conducted using steam co-gasification technology on selected coals,flotation concentrates and Refuse Derived Fuel(RDF)alternative fuel.Selected low-quality coals were combined with RDF alternative fuel in a process aimed at hydrogen production.The experiments produced gas with hydrogen concentrations ranging from 67%(vol.)to 68%(vol.)with low methane concentrations.It was observed that the addition of alternative fuels helped to increase the hydrogen concentration in syngas.Attention was paid to the catalytic ability of the metal oxides contained in the fuel blend,with particular reference to K_(2)O and Al_(2)O_(3)and TiO_(2).
