The research introduced the flowchart of organic-material and plant seeds spraying and a case of "Dasi" Highway, the highway from Daxing to Sinan in Guizhou Province, a part of a National Highway from Hang...The research introduced the flowchart of organic-material and plant seeds spraying and a case of "Dasi" Highway, the highway from Daxing to Sinan in Guizhou Province, a part of a National Highway from Hangzhou to Ruili, cal ed Hangrui Highway, slope protection. The flowchart included slope cleaning, net preparation, anchor fixation, adding vegetation-growth plate, spraying organic materi-als, coverage of non-woven fabrics, and maintenance. The technique is proved much efficient in protecting and greening road sideslopes consisting of weathered rocks or hard rocks, which provides a solution for abrupt slope greening technology.展开更多
Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes,pressure drop of compact dust cake causes problems in efficiency and economy, which has received inc...Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes,pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing attention and still remains challenging. In this study, we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification(controlling of ambient humidity), were employed and proved to be both effective. The regeneration frequency of the filter could be reduced by 55% with ultrasonic atomization, while steam humidification could lead to a 78% reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an optimized droplet-to-particle ratio. With the ratio of 1.53 and 0.0282, the maximum mass loading was 552 g·m-2upon the ultrasonic atomization and 720 g·m-2upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.展开更多
A parameter, known as the parameter of humidification vibration deformation, was proposed, describing quantitatively the impact of water content on vibration settlement deformation, and its relationship with humidific...A parameter, known as the parameter of humidification vibration deformation, was proposed, describing quantitatively the impact of water content on vibration settlement deformation, and its relationship with humidification water content, dynamic shear stress peak value, initial consolidation stress and vibration frequency was built. The result shows that 1) the parameter of humidification vibration deformation increases with the vibration shear stress peak value increasing. 2) The humidification water content has significant influence on the curve of the parameter of humidification vibration deformation and the peak vibration shear stress. When the humidification water content is low, the curve increases slowly. However, when the humidification water content is high, the curve increases rapidly. 3) Initial consolidation stress has significant influence on the humidification vibration deformation coefficient. When initial consolidation stress is not large enough to destroy the loess structure, with initial consolidation stress increasing, the humidification vibration deformation coefficient decreases. On the contrary, the humidification vibration deformation coefficient increases with initial consolidation stress increasing. 4) With the increase of vibration time, the parameter of humidification vibration settlement shows an increasing trend overall. The initial dynamic shear stress peak value and humidification water content all have significant effects on the curve of the parameter of humidification vibration settlement and vibration time. However, the humidification water content is even more significant.展开更多
Wetting Heat of various ranks of coals in water was measured by using SETARAM C80D Calorimeter. The data were correlated to coals' slurryability which is characterized by the solid load at the viscosity of 1 Pa...Wetting Heat of various ranks of coals in water was measured by using SETARAM C80D Calorimeter. The data were correlated to coals' slurryability which is characterized by the solid load at the viscosity of 1 Pa's and 25℃. The results showed that the heat of wetting by wa-ter decreases as coal rank increases in the range of brawn coal to bituminous coaI with carbon content of 89% ~90% (daf), and then, increases a little for anthracite. This trend fitted well to the relationship of slurryability to coal rank. The heat of wetting was also correlated to the inher-ent moisture content and the oxygen content of coal, which are commonly considered as slurrya-bility indication parameters. Hence, the wetting heat is another measure of coal's slurryability.展开更多
In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic...In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic Wickerhamomyces anomalus strains from the fermentation broth of Arabica coffee in Baoshan, Yunnan during wet processing with pectase activity as an indicator. The results showed that the five strains all synthesized pectin lyase(PL), polygalacturonase(PG), and pectin methylesterase(PM).Among them, strain CAP5 had strong ability to produce PG and PL,while strain CAP4 secreted a large amount of PM. Under optimized conditions, the activity of PG, PL, and PM of the five strains came in at 250.17~411.20 U/mL, 12.98~16.55 U/mL, and 208.52~322.83 U/mL,respectively. The four factors of nitrogen source concentration,fermentation time, Mn2+ concentration, and pH value were optimized and the optimal pectinase-producing fermentation conditions for five strains were as follows: peptone 2.2 g/L, fermentation time 30 h, Mn2+ 1.5 mmol/L, and pH 4.3. After fermentation under the optimized conditions, the maximum PG activity of CAP5 amounted to 411.20 U/mL, 114.03% higher than that before optimization.Meanwhile, the PG activity of strains CAP3, CAP4, CAP8, and CAP10 increased by 86.74%, 114.55%, 65.79%, and 66.07%,respectively, and the activity of PL and PM of the five strains rose 150.35%~218.56% and 341.07%~418.52%, respectively. These findings suggested that W. anomalus strains could be used as coffee starter and had great potential for the lysis of pectin.展开更多
Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in...Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in the membrane electrode assembly (MEA) of each cell, in which the moisture of the cathode exhaust gas could transfer through the membrane to humidify anode or cathode dry gas. With a simple model, the relative humidity (RH) of the dry air exhaust from a membrane humidifier with 100% RH stream as a counter flow is calculated to be 60.0%, which is very close to the experimental result (62.2%). Fuel cell performances with hydrogen humidifying, air humidifying and no humidifying are compared at 50, 60 and 70°C and the results indicate that humidifying is necessary and the novel design with humidifying zone in MEA is effective to humidify dry reactants. The hydrogen humidifying shows better performance in short term, while water recovered is limited and the stability is not as good as air humidifying. It is recommended that both air and hydrogen should be humidified with proper design of the humidifying zones in MEA and plates.展开更多
This investigation focused on the analysis of using the M-cycle (Maisotsenko cycle) to improve the efficiency of a gas turbine engine. By combining the M-cycle with an open Brayton cycle, a new cycle, is known as th...This investigation focused on the analysis of using the M-cycle (Maisotsenko cycle) to improve the efficiency of a gas turbine engine. By combining the M-cycle with an open Brayton cycle, a new cycle, is known as the MCTC (Maisotsenko combustion turbine cycle), was formed. The MCTC used an indirect evaporative air cooler as a saturator with a gas turbine engine. The saturator was applied on the side of the turbine exhaust (M-cycle#2) in the analysis. The analysis included calculations and the development of an EES (engineering equation solver) code to model the MCTC system performance. The resulting performance curves were graphed to show the effects of several parameters on the thermal efficiency and net power output of the gas turbine engine. The models were also compared with actual experimental test that results from a gas turbine engine. Conclusions and discussions of results are also given.展开更多
Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one under...Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one understands the phenomenon "natural" likely to occur, with a probability of more or less large occurrence. For the phenomenon of withdrawal-swelling of the argillaceous grounds, one will speak about strong, average or weak risk. This article returns within the framework's study of risk withdrawal-swelling or dryness-humidification of the argillaceous Mames of the area of Ouled Fayet and Cheraga of Algiers.展开更多
In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of ...In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of wood is a promising technology but this has notbeen widely accepted commercially, partially due to the lack of understanding of the dryingphenomena occurred during drying. In this work, experimental investigation was performed to quantifythe heat transfer between wood surface and surrounding moist air or superheated steam. In theexperiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperaturesof 60℃/50℃, 90℃/60℃, 120℃/70℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The lasttwo schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. Thecirculation velocity over the board surface was controlled at 4.2m·s^(-1). Two additional runs(90℃/60℃) using air velocities of 2.4 m·s^(-1) and 4.8 m·s^(-1) were performed to check theeffect of the circulation velocity. During drying, sample weight and temperatures at wood surfaceand different depths were continuously measured. Prom these measurements, changes in woodtemperature and moisture content were calculated and external heat-transfer coefficient wasdetermined for both the moist air and the superheated steam drying.展开更多
Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate t...Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25℃, NaCl concentration 4.0mol/L, mass ratio of ore slurry liquid to solid (mL/mS) 20, electric charge per gram Mo 0.522C, pH value of original slurry 8, anodic current density 700A·m-2 (cell potential 2.72.9V), the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60g/L at low mL/mS of 8 and low electric charge of 0.373C.展开更多
Vibrated fluidized bed air classification is completely different from traditional screening in principle. It extracts fine coal from moist raw coal by entrainment of an ascending airflow in a vibrated fluidized bed. ...Vibrated fluidized bed air classification is completely different from traditional screening in principle. It extracts fine coal from moist raw coal by entrainment of an ascending airflow in a vibrated fluidized bed. Pilot tests showed that air classification efficiencies varied from 74.85% to 93.84% at cut-size 6, 4, 3, 2, 1, and 0.5 mm when free moisture of coal is in the range of 1.7% to 9.5%, and ash contents of fine coal products were 2%~3% lower than those of the same size fractions in feed, and 4%~10% lower than those of feeds for most cases because of the density differences between coal and waste, which is beneficial to producing lower ash fine coal from raw coal as fuel of blast furnaces or pulverized coal firing boilers. A commercial unit of 100 t/h has been in smooth operation, and several 300~400 t/h units are in plan or construction.展开更多
The effect of direct electric current on the wetting behavior of molten Bi on Cu substrate at 370℃ was investigated by the sessile drop method. The wettability of molten Bi on Cu without an applied current is poor an...The effect of direct electric current on the wetting behavior of molten Bi on Cu substrate at 370℃ was investigated by the sessile drop method. The wettability of molten Bi on Cu without an applied current is poor and the spreading time required to form the steady-state contact angle (about 102°) is approximately 30 min. With the increase of the applied electric current, the spreading of molten Bi on Cu is accelerated significantly and the steady-state contact angle decreases considerably. The cross-section SEM micrographs of the solidified Bi droplet on Cu substrate show that the electric current has a marked effect on the convection of melt. Correspondingly, the application of an electric current obviously enhances the dissolution of Cu into Bi melt, which may change the wetting triple line configuration. The improvement of wettability induced by electric current is also related to the additional driving force for wetting provided by the electromagnetic pressure gradient force.展开更多
The work presents a parametric analysis of the performance of a solar-driven thermoelectric system to dehumidify air and produce fresh water. The system is combined with a solar distiller humidifying ambient air to en...The work presents a parametric analysis of the performance of a solar-driven thermoelectric system to dehumidify air and produce fresh water. The system is combined with a solar distiller humidifying ambient air to enhance distillate output to meet the specified fresh water needs for a residential application. The presented system is a totally renewable energy-based system taking advantage of the clean solar energy. A model is developed to simulate the air dehumidification process using TEC (thermoelectrically cooled) channels. An optimization problem for setting system operational parameters is formulated to meet the fresh water requirement of 10 liters per day for a typical residential application in the Lebanese coastal humid climate. Using five TEC channels of length of 1.2 m and area of 0.07 - 0.05 m^2 integrated with 1.2 m^2 solar distiller is capable of meeting the water demand, where the air mass flow rate introduced to each TEC channel is optimally set at 0.0155 kg/s. The optimal electrical current input to the TEC modules from the photovoltaic solar panels varied depending on the month and is set at 2.2 A in June, 2.1 A in July and 2.0 A in August, September and October per each TEC module.展开更多
To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass...To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass content(LDMC)) and chemical traits(leaf N concentration(LNC) and leaf phosphorus(P) concentration(LPC)) of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates(0 g N/(m2·yr), 6 g N/(m2·yr), 12 g N/(m2·yr) and 24 g N/(m2·yr)) in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands.展开更多
A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean ...A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters(depth: 214.73±152.22 cm, temperature 27.68±4.26℃, transparency 123±82 cm, p H 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters(p H 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life(fauna and flora) of this important fresh water body of Bangladesh.展开更多
Coal accounts for about 70% of the primary energy sources in China. The environmental pollution and resources waste involved with coal processing and utilization are serious. It is therefore urgent to develop highly-e...Coal accounts for about 70% of the primary energy sources in China. The environmental pollution and resources waste involved with coal processing and utilization are serious. It is therefore urgent to develop highly-efficient coal resources utilization theory and methods with low-carbon discharge. Based on our long-term basic research and technology development, the progress in beneficiation, cleaning, and trans- formation of coal, which includes dense phase fluidized bed dry beneficiation, deep screening of wet fine coal, micro-bubble flotation column separation, molecular coal chemistry, and transformation and sepa- ration of coal and its derivatives into value-added chemicals under mild conditions, is discussed.展开更多
The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high tempe...The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.展开更多
Artificial neural network has unique advantages for massively parallel processing, distributed storage capacity and self-learning ability. The paper mainly constructs neural network identifier and neural network contr...Artificial neural network has unique advantages for massively parallel processing, distributed storage capacity and self-learning ability. The paper mainly constructs neural network identifier and neural network controller for system identification and control on temperature and hmnidity of heating and drying system of materials. And the paper introduces the structure and principles of neural network, and focuses on analyzing learning algorithm, training algorithm and limitation of the most widely applied multi-layer feed-forward neural network ( BP network) , based on which the paper proposes introducing momentum to improve BP network.展开更多
文摘The research introduced the flowchart of organic-material and plant seeds spraying and a case of "Dasi" Highway, the highway from Daxing to Sinan in Guizhou Province, a part of a National Highway from Hangzhou to Ruili, cal ed Hangrui Highway, slope protection. The flowchart included slope cleaning, net preparation, anchor fixation, adding vegetation-growth plate, spraying organic materi-als, coverage of non-woven fabrics, and maintenance. The technique is proved much efficient in protecting and greening road sideslopes consisting of weathered rocks or hard rocks, which provides a solution for abrupt slope greening technology.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2013AA065003)the National Natural Science Foundation of China(No.21276011)the Ph.D.Programs Foundation of Ministry of Education of China(200800100001)
文摘Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes,pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing attention and still remains challenging. In this study, we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification(controlling of ambient humidity), were employed and proved to be both effective. The regeneration frequency of the filter could be reduced by 55% with ultrasonic atomization, while steam humidification could lead to a 78% reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an optimized droplet-to-particle ratio. With the ratio of 1.53 and 0.0282, the maximum mass loading was 552 g·m-2upon the ultrasonic atomization and 720 g·m-2upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.
基金Foundation item: Project(51178392) supported by the National Natural Science Foundation of China
文摘A parameter, known as the parameter of humidification vibration deformation, was proposed, describing quantitatively the impact of water content on vibration settlement deformation, and its relationship with humidification water content, dynamic shear stress peak value, initial consolidation stress and vibration frequency was built. The result shows that 1) the parameter of humidification vibration deformation increases with the vibration shear stress peak value increasing. 2) The humidification water content has significant influence on the curve of the parameter of humidification vibration deformation and the peak vibration shear stress. When the humidification water content is low, the curve increases slowly. However, when the humidification water content is high, the curve increases rapidly. 3) Initial consolidation stress has significant influence on the humidification vibration deformation coefficient. When initial consolidation stress is not large enough to destroy the loess structure, with initial consolidation stress increasing, the humidification vibration deformation coefficient decreases. On the contrary, the humidification vibration deformation coefficient increases with initial consolidation stress increasing. 4) With the increase of vibration time, the parameter of humidification vibration settlement shows an increasing trend overall. The initial dynamic shear stress peak value and humidification water content all have significant effects on the curve of the parameter of humidification vibration settlement and vibration time. However, the humidification water content is even more significant.
文摘Wetting Heat of various ranks of coals in water was measured by using SETARAM C80D Calorimeter. The data were correlated to coals' slurryability which is characterized by the solid load at the viscosity of 1 Pa's and 25℃. The results showed that the heat of wetting by wa-ter decreases as coal rank increases in the range of brawn coal to bituminous coaI with carbon content of 89% ~90% (daf), and then, increases a little for anthracite. This trend fitted well to the relationship of slurryability to coal rank. The heat of wetting was also correlated to the inher-ent moisture content and the oxygen content of coal, which are commonly considered as slurrya-bility indication parameters. Hence, the wetting heat is another measure of coal's slurryability.
文摘In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic Wickerhamomyces anomalus strains from the fermentation broth of Arabica coffee in Baoshan, Yunnan during wet processing with pectase activity as an indicator. The results showed that the five strains all synthesized pectin lyase(PL), polygalacturonase(PG), and pectin methylesterase(PM).Among them, strain CAP5 had strong ability to produce PG and PL,while strain CAP4 secreted a large amount of PM. Under optimized conditions, the activity of PG, PL, and PM of the five strains came in at 250.17~411.20 U/mL, 12.98~16.55 U/mL, and 208.52~322.83 U/mL,respectively. The four factors of nitrogen source concentration,fermentation time, Mn2+ concentration, and pH value were optimized and the optimal pectinase-producing fermentation conditions for five strains were as follows: peptone 2.2 g/L, fermentation time 30 h, Mn2+ 1.5 mmol/L, and pH 4.3. After fermentation under the optimized conditions, the maximum PG activity of CAP5 amounted to 411.20 U/mL, 114.03% higher than that before optimization.Meanwhile, the PG activity of strains CAP3, CAP4, CAP8, and CAP10 increased by 86.74%, 114.55%, 65.79%, and 66.07%,respectively, and the activity of PL and PM of the five strains rose 150.35%~218.56% and 341.07%~418.52%, respectively. These findings suggested that W. anomalus strains could be used as coffee starter and had great potential for the lysis of pectin.
基金Supported by the National High Technology Research and Development Program of China (2008AA05Z104)
文摘Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in the membrane electrode assembly (MEA) of each cell, in which the moisture of the cathode exhaust gas could transfer through the membrane to humidify anode or cathode dry gas. With a simple model, the relative humidity (RH) of the dry air exhaust from a membrane humidifier with 100% RH stream as a counter flow is calculated to be 60.0%, which is very close to the experimental result (62.2%). Fuel cell performances with hydrogen humidifying, air humidifying and no humidifying are compared at 50, 60 and 70°C and the results indicate that humidifying is necessary and the novel design with humidifying zone in MEA is effective to humidify dry reactants. The hydrogen humidifying shows better performance in short term, while water recovered is limited and the stability is not as good as air humidifying. It is recommended that both air and hydrogen should be humidified with proper design of the humidifying zones in MEA and plates.
文摘This investigation focused on the analysis of using the M-cycle (Maisotsenko cycle) to improve the efficiency of a gas turbine engine. By combining the M-cycle with an open Brayton cycle, a new cycle, is known as the MCTC (Maisotsenko combustion turbine cycle), was formed. The MCTC used an indirect evaporative air cooler as a saturator with a gas turbine engine. The saturator was applied on the side of the turbine exhaust (M-cycle#2) in the analysis. The analysis included calculations and the development of an EES (engineering equation solver) code to model the MCTC system performance. The resulting performance curves were graphed to show the effects of several parameters on the thermal efficiency and net power output of the gas turbine engine. The models were also compared with actual experimental test that results from a gas turbine engine. Conclusions and discussions of results are also given.
文摘Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one understands the phenomenon "natural" likely to occur, with a probability of more or less large occurrence. For the phenomenon of withdrawal-swelling of the argillaceous grounds, one will speak about strong, average or weak risk. This article returns within the framework's study of risk withdrawal-swelling or dryness-humidification of the argillaceous Mames of the area of Ouled Fayet and Cheraga of Algiers.
文摘In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of wood is a promising technology but this has notbeen widely accepted commercially, partially due to the lack of understanding of the dryingphenomena occurred during drying. In this work, experimental investigation was performed to quantifythe heat transfer between wood surface and surrounding moist air or superheated steam. In theexperiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperaturesof 60℃/50℃, 90℃/60℃, 120℃/70℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The lasttwo schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. Thecirculation velocity over the board surface was controlled at 4.2m·s^(-1). Two additional runs(90℃/60℃) using air velocities of 2.4 m·s^(-1) and 4.8 m·s^(-1) were performed to check theeffect of the circulation velocity. During drying, sample weight and temperatures at wood surfaceand different depths were continuously measured. Prom these measurements, changes in woodtemperature and moisture content were calculated and external heat-transfer coefficient wasdetermined for both the moist air and the superheated steam drying.
文摘Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25℃, NaCl concentration 4.0mol/L, mass ratio of ore slurry liquid to solid (mL/mS) 20, electric charge per gram Mo 0.522C, pH value of original slurry 8, anodic current density 700A·m-2 (cell potential 2.72.9V), the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60g/L at low mL/mS of 8 and low electric charge of 0.373C.
文摘Vibrated fluidized bed air classification is completely different from traditional screening in principle. It extracts fine coal from moist raw coal by entrainment of an ascending airflow in a vibrated fluidized bed. Pilot tests showed that air classification efficiencies varied from 74.85% to 93.84% at cut-size 6, 4, 3, 2, 1, and 0.5 mm when free moisture of coal is in the range of 1.7% to 9.5%, and ash contents of fine coal products were 2%~3% lower than those of the same size fractions in feed, and 4%~10% lower than those of feeds for most cases because of the density differences between coal and waste, which is beneficial to producing lower ash fine coal from raw coal as fuel of blast furnaces or pulverized coal firing boilers. A commercial unit of 100 t/h has been in smooth operation, and several 300~400 t/h units are in plan or construction.
基金Project(50704001) supported by the National Natural Science Foundation of China
文摘The effect of direct electric current on the wetting behavior of molten Bi on Cu substrate at 370℃ was investigated by the sessile drop method. The wettability of molten Bi on Cu without an applied current is poor and the spreading time required to form the steady-state contact angle (about 102°) is approximately 30 min. With the increase of the applied electric current, the spreading of molten Bi on Cu is accelerated significantly and the steady-state contact angle decreases considerably. The cross-section SEM micrographs of the solidified Bi droplet on Cu substrate show that the electric current has a marked effect on the convection of melt. Correspondingly, the application of an electric current obviously enhances the dissolution of Cu into Bi melt, which may change the wetting triple line configuration. The improvement of wettability induced by electric current is also related to the additional driving force for wetting provided by the electromagnetic pressure gradient force.
文摘The work presents a parametric analysis of the performance of a solar-driven thermoelectric system to dehumidify air and produce fresh water. The system is combined with a solar distiller humidifying ambient air to enhance distillate output to meet the specified fresh water needs for a residential application. The presented system is a totally renewable energy-based system taking advantage of the clean solar energy. A model is developed to simulate the air dehumidification process using TEC (thermoelectrically cooled) channels. An optimization problem for setting system operational parameters is formulated to meet the fresh water requirement of 10 liters per day for a typical residential application in the Lebanese coastal humid climate. Using five TEC channels of length of 1.2 m and area of 0.07 - 0.05 m^2 integrated with 1.2 m^2 solar distiller is capable of meeting the water demand, where the air mass flow rate introduced to each TEC channel is optimally set at 0.0155 kg/s. The optimal electrical current input to the TEC modules from the photovoltaic solar panels varied depending on the month and is set at 2.2 A in June, 2.1 A in July and 2.0 A in August, September and October per each TEC module.
基金Under the auspices of Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues of Chinese Academy of Sciences(No.XDA05050508)Ministry of Land and Resources Program(No.201111023,GZH201100203)Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology,Ministry of Land and Resources(No.MRE201101)
文摘To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass content(LDMC)) and chemical traits(leaf N concentration(LNC) and leaf phosphorus(P) concentration(LPC)) of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates(0 g N/(m2·yr), 6 g N/(m2·yr), 12 g N/(m2·yr) and 24 g N/(m2·yr)) in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands.
基金Supported by the United States Department of Agriculture(USDA) through the Project ‘‘Ex situ conservation of some indigenous fishes of Bangladesh by selecting the best stock through DNA markers’’(BGARS-120)
文摘A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters(depth: 214.73±152.22 cm, temperature 27.68±4.26℃, transparency 123±82 cm, p H 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters(p H 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life(fauna and flora) of this important fresh water body of Bangladesh.
基金support from the National Natural Science Foundation of China(No. 50921002)
文摘Coal accounts for about 70% of the primary energy sources in China. The environmental pollution and resources waste involved with coal processing and utilization are serious. It is therefore urgent to develop highly-efficient coal resources utilization theory and methods with low-carbon discharge. Based on our long-term basic research and technology development, the progress in beneficiation, cleaning, and trans- formation of coal, which includes dense phase fluidized bed dry beneficiation, deep screening of wet fine coal, micro-bubble flotation column separation, molecular coal chemistry, and transformation and sepa- ration of coal and its derivatives into value-added chemicals under mild conditions, is discussed.
基金National Science and Technology Support Program of China ( No. 2009BAG15B01)Key Pro-grams for Science and Technology Development of Chinese Transportation Industry( No. 2008-353-332-170)
文摘The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.
文摘Artificial neural network has unique advantages for massively parallel processing, distributed storage capacity and self-learning ability. The paper mainly constructs neural network identifier and neural network controller for system identification and control on temperature and hmnidity of heating and drying system of materials. And the paper introduces the structure and principles of neural network, and focuses on analyzing learning algorithm, training algorithm and limitation of the most widely applied multi-layer feed-forward neural network ( BP network) , based on which the paper proposes introducing momentum to improve BP network.