The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational param...The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational parameter. A 14L sequencing batch reactor was operated at 23℃ for 8 months, with an input of domestic wastewater. There was a prolgrammed decrease of the airflow rate to 28L·h^-1, the corresponding average dissolved oxygen (DO) was 0.32mg·h^-1, and the average nitrite accumulation rate increased to 92.4% in 3 weeks. Subsequently, further increase in the airflow rate to 48L·h^-1 did not destroy the partial nitrification to nitrite, with average DO of 0.60mg·h^-1 and nitrite accumulating rate of 95.6%. The results showed that limited airflow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate and that this system showed relatively stability at higher airflow rate independent of pH and temperature. About 50% of influent total nitrogen was eliminated coupling with partial nitrification, taking the advantage of low DO during the reaction.展开更多
The materials used in fuel cells are currently the subject of much research, particularly those of the cathode which is a key element for the different functions that it provides. In our work the authors became intere...The materials used in fuel cells are currently the subject of much research, particularly those of the cathode which is a key element for the different functions that it provides. In our work the authors became interested in the different materials used for the cathode, which are usually ceramic, and some of their physical properties between different electrical conductivity (electronic, ionic), the coefficient of thermal expansion and chemical compatibility between different materials used in the stack. Not to mention, however, the various parameters that influence these properties, such as structure, the sintering temperature, dope, and the operating temperature of the battery. The main objective of research in this area is to improve battery performance by researching new materials and new manufacturing technologies that will increase the electrical conductivity while trying to lower the temperature operating the latter as much as possible while keeping it above 650℃, In doing so, the longevity of the battery will be increased which will have a direct impact on manufacturing costs of the battery, and thus greater use thereof.展开更多
A two-meter parabolic solar concentration dish has been modulated to produce boiled water over 100℃ for various purposes of central heating services. For an effective performance, the system required both continuous ...A two-meter parabolic solar concentration dish has been modulated to produce boiled water over 100℃ for various purposes of central heating services. For an effective performance, the system required both continuous exposure of the dish to sunlight during the day time as well as to an electric control circuit (tracking system). The amount of the potable water was dependent particularly on the accurate centering of the system which could increase upon preheating. This system has therefore been possible to heat up water at home via increasing the temperature in hot tank by both covering the hot water tank and isolating it from the surroundings using insulators. Applications of a successful parabolic solar concentration has also been designed to provide desalinated water for domestic usage which operates with temperatures higher than other types of the solar radiation for the future.展开更多
To create control laws of the cutting process on the heavy lathe, the temperature-force model of optimization of cutting conditions for turning was selected. The models to manage the process of cutting on heavy lathe ...To create control laws of the cutting process on the heavy lathe, the temperature-force model of optimization of cutting conditions for turning was selected. The models to manage the process of cutting on heavy lathe in real time were created. It was found that the optimization of the cutting process must be carried out according to the criteria: productivity, cost and tool life. The hardware structure of the adaptive control system for heavy lathe was developed and its dynamic performance was investigated. The system provides function of the cutting speed of adaptive control and the possibility of compensation of linear, nonlinear and temperature-related inaccuracies. Research results were implemented in the prototype of adaptive control system for heavy lathe and the integral complex of optimal control of an adaptive technological system.展开更多
This paper presents an extensive study of the heat pump cycle and associated working fluids to generate electricity from low temperature industrial waste heat. An Aspen Plus simulation has been developed to evaluate t...This paper presents an extensive study of the heat pump cycle and associated working fluids to generate electricity from low temperature industrial waste heat. An Aspen Plus simulation has been developed to evaluate the effect of various working fluids on the net heat pump efficiency over a wide range of turbine inlet temperatures between 50℃ and 250℃. One hundred eight (108) refi'igerants were investigated from the environmental classifications of Hydrochlorofluorocarbons (HCFC), Hydrofluorocarbons (HFC), Chlorofluorocarbons (CFC) and Hydrocarbons (HC) with boiling points between -88.65 ℃ and 110.65℃. Net efficiency, which ranged from 0.1% to 25.8% in this work tends to increases with the temperature of the waste heat. Results of the present study demonstrate that working fluid R41 (with source temperature of 44 ℃) provides the maximum efficiency among those evaluated. Refrigerants R13B1 and R32 provide the best efficiency for waste heat source temperatures ranges 60 - 67 ℃ and 68 - 78℃ respectively. Ammonia shows the highest efficiency from 79℃ to 132 ℃. Refrigerants R31, R21, 17,30 and benzene perform well in the temperature ranges 133-151 ℃, 152-178 ℃, 179-236℃ and 237-250 ℃respectively. The optimal heat pump systems are applied to the hybrid copper sulfate-copper oxide thermochemical cycle for hydrogen production from water. 100.8 MW of electrical energy is produced, which increased the efficiency from 24.1% to 25.9%.展开更多
A liquid metal enabled corrosion sculpture technique for quickly fabricating complex pattems on aluminum substrate is proposed and experimentally demonstrated. According to the conceptual investigation, it is clarifie...A liquid metal enabled corrosion sculpture technique for quickly fabricating complex pattems on aluminum substrate is proposed and experimentally demonstrated. According to the conceptual investigation, it is clarified that the width and the depth of a printed track are dominated by sculpture time and working temperature. The printed size can reach small values of 38 μm through controlling the sculpture time for 60 s. As the sculpture time was increased from 5 to 25 rain at 20℃, the depth of the fabricated pattern was improved from 13.3 to 25.6 μm. The sculptured depth of the pattern would increase from 13.3 to 106.9 μm when the sculpture time was fixed at 5 min and the temperature was raised from 20 to 60℃. To investigate the sculpture behavior in detail, the phases and microstructure of sculpture surface were quantitatively measured via a group of microscope imaging system with fundamental mechanisms interpreted. The present liquid metal sculpture method on aluminum substrate adds a new valuable soft tool for current metal engraving technology family.展开更多
Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies.In this article,three-dimensional nitrogen-doped porous carbon materials(NDPC-X,in whic...Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies.In this article,three-dimensional nitrogen-doped porous carbon materials(NDPC-X,in which X represents the pyrolysis temperature) were fabricated by simultaneous carbonization and activation of polypyrrole-coated paper towel protected by a silica layer followed by acid etching.The material had a high specific surface area(1,123.40 m^2/g).The as-obtained NDPC-900 displayed outstanding activity as a catalyst for the oxygen reduction reaction(ORR) as well as an electrode with a high specific capacitance in a supercapacitor in an alkaline medium.The NDPC-900 catalyst for the ORR exhibited a more positive reduction peak potential of à0.068 V(vs.Hg|HgCl^2) than that of Pt/C(-0.121 V),as well as better cycling stability and stronger methanol tolerance.Moreover,the NDPC-900 had a high specific capacitance of 379.50 F/g at a current density of 1 A/g,with a retention rate of 94.5% after 10,000 cycles in 6 mol/L KOH electrolyte when used as an electrode in a supercapacitor.All these results were attributed to the effect of a large surface area,which provided electrochemically active sites.This work introduces an effective way to use biomass-derived materials for the synthesis of promising bifunctional carbon material for electrochemical energy conversion and storage devices.展开更多
Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which ...Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which depended on shaping craft and working temperature were conducted by quasi-static tests.Comparative experiments indicated that the heat setting temperature affect the elastic modulus non-monotonously but has little effect on the loss factor of SMAMR in both martensite and austenite phases.With the increase of the heat setting time,the elastic modulus of SMAMR monotonously decreases and the reduction of loss factor is unobvious.With the present shaping craft,SMAMR exhibits the anisotropy in moulding and non-moulding directions,which is affected by the heat setting process and working temperature.It was proved that the mechanical properties have approximately linear relationship with temperature during the phase transition process.Due to its temperature-dependent mechanical properties,SMAMR that experiences the heat setting procedure is expected to be used in active vibration control systems with varying temperature-dependent stiffness and damping coefficients to provide superior vibration control performance.展开更多
In this work, we fabricated a monodisperse nanocomposite by coating gold nanorods (AuNRs) with a layer of biocompatible, stable carbon, obtaining AuNR@Carbon core-shell nanocapsules, which without any functionalizat...In this work, we fabricated a monodisperse nanocomposite by coating gold nanorods (AuNRs) with a layer of biocompatible, stable carbon, obtaining AuNR@Carbon core-shell nanocapsules, which without any functionalization could be used as a molecule loading material due to its high surface areas. In this system, the AuNR core had a high-absorption cross section for con- version of near-infrared light to heat, which could be ex- plored for local hyperthermia. The carbon shell, which was biocompatible and stable even under concentrated acidic and alkaline conditions, was able to adsorb molecules with n-n interactions or electrostatic interactions. In comparison with AuNR@SiO2, AuNR@Carbon nanocapsules demon- strate the following merits: (1) simple and green synthesis method, (2) far more stable with respect to high-tem- perature stability and (3) larger molecule loading capacity, which indicate great potential in the biomedical applications.展开更多
基金Supported by Funding Project for Academic Human Resources Development in Institutions of Higher Leading under the Juris-diction of Beijing Municipality [PHR(IHLB)], the National Natural Science Foundation of China (No.50478040)the Na-tional Key Technologies R&D Program of China (No.2006BAC19B03).
文摘The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational parameter. A 14L sequencing batch reactor was operated at 23℃ for 8 months, with an input of domestic wastewater. There was a prolgrammed decrease of the airflow rate to 28L·h^-1, the corresponding average dissolved oxygen (DO) was 0.32mg·h^-1, and the average nitrite accumulation rate increased to 92.4% in 3 weeks. Subsequently, further increase in the airflow rate to 48L·h^-1 did not destroy the partial nitrification to nitrite, with average DO of 0.60mg·h^-1 and nitrite accumulating rate of 95.6%. The results showed that limited airflow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate and that this system showed relatively stability at higher airflow rate independent of pH and temperature. About 50% of influent total nitrogen was eliminated coupling with partial nitrification, taking the advantage of low DO during the reaction.
文摘The materials used in fuel cells are currently the subject of much research, particularly those of the cathode which is a key element for the different functions that it provides. In our work the authors became interested in the different materials used for the cathode, which are usually ceramic, and some of their physical properties between different electrical conductivity (electronic, ionic), the coefficient of thermal expansion and chemical compatibility between different materials used in the stack. Not to mention, however, the various parameters that influence these properties, such as structure, the sintering temperature, dope, and the operating temperature of the battery. The main objective of research in this area is to improve battery performance by researching new materials and new manufacturing technologies that will increase the electrical conductivity while trying to lower the temperature operating the latter as much as possible while keeping it above 650℃, In doing so, the longevity of the battery will be increased which will have a direct impact on manufacturing costs of the battery, and thus greater use thereof.
文摘A two-meter parabolic solar concentration dish has been modulated to produce boiled water over 100℃ for various purposes of central heating services. For an effective performance, the system required both continuous exposure of the dish to sunlight during the day time as well as to an electric control circuit (tracking system). The amount of the potable water was dependent particularly on the accurate centering of the system which could increase upon preheating. This system has therefore been possible to heat up water at home via increasing the temperature in hot tank by both covering the hot water tank and isolating it from the surroundings using insulators. Applications of a successful parabolic solar concentration has also been designed to provide desalinated water for domestic usage which operates with temperatures higher than other types of the solar radiation for the future.
文摘To create control laws of the cutting process on the heavy lathe, the temperature-force model of optimization of cutting conditions for turning was selected. The models to manage the process of cutting on heavy lathe in real time were created. It was found that the optimization of the cutting process must be carried out according to the criteria: productivity, cost and tool life. The hardware structure of the adaptive control system for heavy lathe was developed and its dynamic performance was investigated. The system provides function of the cutting speed of adaptive control and the possibility of compensation of linear, nonlinear and temperature-related inaccuracies. Research results were implemented in the prototype of adaptive control system for heavy lathe and the integral complex of optimal control of an adaptive technological system.
文摘This paper presents an extensive study of the heat pump cycle and associated working fluids to generate electricity from low temperature industrial waste heat. An Aspen Plus simulation has been developed to evaluate the effect of various working fluids on the net heat pump efficiency over a wide range of turbine inlet temperatures between 50℃ and 250℃. One hundred eight (108) refi'igerants were investigated from the environmental classifications of Hydrochlorofluorocarbons (HCFC), Hydrofluorocarbons (HFC), Chlorofluorocarbons (CFC) and Hydrocarbons (HC) with boiling points between -88.65 ℃ and 110.65℃. Net efficiency, which ranged from 0.1% to 25.8% in this work tends to increases with the temperature of the waste heat. Results of the present study demonstrate that working fluid R41 (with source temperature of 44 ℃) provides the maximum efficiency among those evaluated. Refrigerants R13B1 and R32 provide the best efficiency for waste heat source temperatures ranges 60 - 67 ℃ and 68 - 78℃ respectively. Ammonia shows the highest efficiency from 79℃ to 132 ℃. Refrigerants R31, R21, 17,30 and benzene perform well in the temperature ranges 133-151 ℃, 152-178 ℃, 179-236℃ and 237-250 ℃respectively. The optimal heat pump systems are applied to the hybrid copper sulfate-copper oxide thermochemical cycle for hydrogen production from water. 100.8 MW of electrical energy is produced, which increased the efficiency from 24.1% to 25.9%.
基金supported by Beijing Municipal Science and Technology Project(Grant No.Z151100003715002)China Postdoctoral Science Foundation funded project(Grant No.2016M590137)
文摘A liquid metal enabled corrosion sculpture technique for quickly fabricating complex pattems on aluminum substrate is proposed and experimentally demonstrated. According to the conceptual investigation, it is clarified that the width and the depth of a printed track are dominated by sculpture time and working temperature. The printed size can reach small values of 38 μm through controlling the sculpture time for 60 s. As the sculpture time was increased from 5 to 25 rain at 20℃, the depth of the fabricated pattern was improved from 13.3 to 25.6 μm. The sculptured depth of the pattern would increase from 13.3 to 106.9 μm when the sculpture time was fixed at 5 min and the temperature was raised from 20 to 60℃. To investigate the sculpture behavior in detail, the phases and microstructure of sculpture surface were quantitatively measured via a group of microscope imaging system with fundamental mechanisms interpreted. The present liquid metal sculpture method on aluminum substrate adds a new valuable soft tool for current metal engraving technology family.
基金supported by the National Natural Science Foundation of China(51473008,51672019)the National Key Research and Development Program of China(2017YFA0206900)the 111 Project(B14009)
文摘Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies.In this article,three-dimensional nitrogen-doped porous carbon materials(NDPC-X,in which X represents the pyrolysis temperature) were fabricated by simultaneous carbonization and activation of polypyrrole-coated paper towel protected by a silica layer followed by acid etching.The material had a high specific surface area(1,123.40 m^2/g).The as-obtained NDPC-900 displayed outstanding activity as a catalyst for the oxygen reduction reaction(ORR) as well as an electrode with a high specific capacitance in a supercapacitor in an alkaline medium.The NDPC-900 catalyst for the ORR exhibited a more positive reduction peak potential of à0.068 V(vs.Hg|HgCl^2) than that of Pt/C(-0.121 V),as well as better cycling stability and stronger methanol tolerance.Moreover,the NDPC-900 had a high specific capacitance of 379.50 F/g at a current density of 1 A/g,with a retention rate of 94.5% after 10,000 cycles in 6 mol/L KOH electrolyte when used as an electrode in a supercapacitor.All these results were attributed to the effect of a large surface area,which provided electrochemically active sites.This work introduces an effective way to use biomass-derived materials for the synthesis of promising bifunctional carbon material for electrochemical energy conversion and storage devices.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51105022,51101008 and 51211130115)Fan Zhou Research Fund (Grant No. 201104021)
文摘Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which depended on shaping craft and working temperature were conducted by quasi-static tests.Comparative experiments indicated that the heat setting temperature affect the elastic modulus non-monotonously but has little effect on the loss factor of SMAMR in both martensite and austenite phases.With the increase of the heat setting time,the elastic modulus of SMAMR monotonously decreases and the reduction of loss factor is unobvious.With the present shaping craft,SMAMR exhibits the anisotropy in moulding and non-moulding directions,which is affected by the heat setting process and working temperature.It was proved that the mechanical properties have approximately linear relationship with temperature during the phase transition process.Due to its temperature-dependent mechanical properties,SMAMR that experiences the heat setting procedure is expected to be used in active vibration control systems with varying temperature-dependent stiffness and damping coefficients to provide superior vibration control performance.
基金supported by the National Basic Research Program of China(2013CB932702)the Program on National Key Scientific Instruments and Equipment Development(2011YQ0301241402)+1 种基金the Science and Technology Development Fund of Macao S.A.R(FDCT,067/2014/A)the Hunan Innovation and Entrepreneurship Program
文摘In this work, we fabricated a monodisperse nanocomposite by coating gold nanorods (AuNRs) with a layer of biocompatible, stable carbon, obtaining AuNR@Carbon core-shell nanocapsules, which without any functionalization could be used as a molecule loading material due to its high surface areas. In this system, the AuNR core had a high-absorption cross section for con- version of near-infrared light to heat, which could be ex- plored for local hyperthermia. The carbon shell, which was biocompatible and stable even under concentrated acidic and alkaline conditions, was able to adsorb molecules with n-n interactions or electrostatic interactions. In comparison with AuNR@SiO2, AuNR@Carbon nanocapsules demon- strate the following merits: (1) simple and green synthesis method, (2) far more stable with respect to high-tem- perature stability and (3) larger molecule loading capacity, which indicate great potential in the biomedical applications.