期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
Performance Study of Refrigeration Units That Use the Refrigerant R-404A by Using Computer Simulation
1
作者 Abed Alrzaq Sleman Alshqirate 《Modern Mechanical Engineering》 2016年第2期67-75,共9页
The performance parameters of vapor compression refrigeration units that used the refrigerant R-404A were studied by developing a computer simulation algorithm. The various performance parameters investigated per one ... The performance parameters of vapor compression refrigeration units that used the refrigerant R-404A were studied by developing a computer simulation algorithm. The various performance parameters investigated per one kilowatt of refrigeration capacity, such as the mass flow rate, the compressor power consumption, the condenser heat rejection rate, the compressor exit temperature and the coefficient of performance. Two refrigeration cycles were tested under various evaporating and condensing temperatures: the standard cycle and the ideal cycle with superheating and sub-cooling. The results of the present work reveal that the compressor power variation over the evaporating temperature range from –10℃ to 15℃at Tc = 40℃ is decreased by 38.8% for standard cycle and by 43.8% for ideal cycle. The compressor power variation over the condensing temperature range from 30℃ to 50℃ at Te = 10℃ is increased by 122% for standard cycle and by 54.5% for ideal cycle. On the other hand, the COP for the ideal cycle with 5℃ superheating and sub-cooling is approximately 25% higher than that of the standard cycle at Te = 10℃ and Tc = 40℃ for the refrigerant R-404A. 展开更多
关键词 Refrigeration Units R-404A Computer Simulation Refrigeration performance parameters
下载PDF
液氧煤油发动机混合比调整技术研究
2
作者 YANG Yongqiang CAO Chen +1 位作者 MA Nan WANG Fei 《Aerospace China》 2023年第2期39-45,共7页
The LM-5B carrier rocket’s first stage is equipped with eight 120 t.thrust high-pressure staged combustion LOX/kerosene engines(YF-100).The YF-100 engine features a throttle valve in the main fuel path,which allows t... The LM-5B carrier rocket’s first stage is equipped with eight 120 t.thrust high-pressure staged combustion LOX/kerosene engines(YF-100).The YF-100 engine features a throttle valve in the main fuel path,which allows the adjustment of the throttle area,thereby controlling the engine’s mixture ratio.Engine parameters for the throttle valve were determined based on design conditions(mixture ratio of 2.6),and the engine was then tested for ignition.After testing,if the mixture ratio was found not to meet the overall requirements of the rocket,the throttle area could be adjusted prior to subsequent ignition or installation in the whole system,enabling a secondary adjustment of the mixture ratio.This paper outlines the methodology for static parameter calculations of the engine and the analysis of internal and external interference factors,and presents a scheme for the secondary adjustment of the engine’s mixture ratio and examines the precision of this secondary adjustment.The mixture ratio adjustment technology can notably reduce the dispersion range of mixture ratios for YF-100 engines.Moreover,the influence of mixture ratio adjustment on engine performance parameters was obtained.The approach of mixture ratio adjustment proposed in this paper lays the technical foundation for the precise adjustment of mixture ratio for future heavy-lift rocket engines. 展开更多
关键词 LM-5B LOX/kerosene engine mixture ratio adjustment performance parameters
下载PDF
Quantitative design of yield components to simulate yield formation for maize in China 被引量:3
3
作者 HOU Hai-peng MA Wei +4 位作者 Mehmood Ali NOOR TANG Li-yuan LI Cong-feng DING Zai-song ZHAO Ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第3期668-679,共12页
Maize(Zea mays L.) stands prominently as one of the major cereal crops in China as well as in the rest of the world.Therefore,predicting the growth and yield of maize for large areas through yield components under hig... Maize(Zea mays L.) stands prominently as one of the major cereal crops in China as well as in the rest of the world.Therefore,predicting the growth and yield of maize for large areas through yield components under high-yielding environments will help in understanding the process of yield formation and yield potential under different environmental conditions.This accurate early assessment of yield requires accuracy in the formation process of yield components as well.In order to formulate the quantitative design for high yields of maize in China,yield performance parameters of quantitative design for high grain yields were evaluated in this study,by utilizing the yield performance equation with normalization of planting density.Planting density was evaluated by parameters including the maximum leaf area index and the maximum leaf area per plant.Results showed that the variation of the maximum leaf area per plant with varying plant density conformed to the Reciprocal Model,which proved to have excellent prediction with root mean square error(RMSE) value of 5.95%.Yield model estimation depicted that the best optimal maximum leaf area per plant was 0.63 times the potential maximum leaf area per plant of hybrids.Yield performance parameters for different yield levels were quantitatively designed based on the yield performance equation.Through validation of the yield performance model by simulating high yields of spring maize in the Inner Mongolia Autonomous Region and Jilin Province,China,and summer maize in Shandong Province,the yield performance equation showed excellent prediction with the satisfactory mean RMSE value(7.72%) of all the parameters.The present study provides theoretical support for the formulation of quantitative design for sustainable high yield of maize in China,through consideration of planting density normalization in the yield prediction process,providing there is no water and nutrient limitation. 展开更多
关键词 MAIZE yield performance parameters high yield yield prediction process quantitative design
下载PDF
Development of Efficient Classification Systems for the Diagnosis of Melanoma
4
作者 S.Palpandi T.Meeradevi 《Computer Systems Science & Engineering》 SCIE EI 2022年第7期361-371,共11页
Skin cancer is usually classified as melanoma and non-melanoma.Melanoma now represents 75%of humans passing away worldwide and is one of the most brutal types of cancer.Previously,studies were not mainly focused on fea... Skin cancer is usually classified as melanoma and non-melanoma.Melanoma now represents 75%of humans passing away worldwide and is one of the most brutal types of cancer.Previously,studies were not mainly focused on feature extraction of Melanoma,which caused the classification accuracy.However,in this work,Histograms of orientation gradients and local binary pat-terns feature extraction procedures are used to extract the important features such as asymmetry,symmetry,boundary irregularity,color,diameter,etc.,and are removed from both melanoma and non-melanoma images.This proposed Effi-cient Classification Systems for the Diagnosis of Melanoma(ECSDM)framework consists of different schemes such as preprocessing,segmentation,feature extrac-tion,and classification.We used Machine Learning(ML)and Deep Learning(DL)classifiers in the classification framework.The ML classifier is Naïve Bayes(NB)and Support Vector Machines(SVM).And also,DL classification frame-work of the Convolution Neural Network(CNN)is used to classify the melanoma and benign images.The results show that the Neural Network(NNET)classifier’achieves 97.17%of accuracy when contrasting with ML classifiers. 展开更多
关键词 MELANOMA BENIGN classification systems performance parameters
下载PDF
Energy and Life Cycle Assessment of Zinc/Water Nanofluid Based Photovoltaic Thermal System
5
作者 Junaid Khan Rashid Ali +1 位作者 Muzammil Zubair Syed Mohd Yahya 《Energy Engineering》 EI 2022年第2期827-846,共20页
Cooling the PV surface in a Photovoltaic Thermal system is a pivotal operational aspect to be taken into account to achieve optimized values of performance parameters in a Photovoltaic Thermal System.The experimental ... Cooling the PV surface in a Photovoltaic Thermal system is a pivotal operational aspect to be taken into account to achieve optimized values of performance parameters in a Photovoltaic Thermal System.The experimental design used in this study facilitates the flow of varying concentrations of Zn-water nanofluid in serpentine copper tubing installed at the rear of the PV panel thereby preventing the PV surface temperature from increasing beyond the threshold value at which a decrease in electrical efficiency starts to occur.This fusion of solar thermal with PV devices leads to better electrical and thermal efficiency values resulting in decreased cell degradation over time and maximization of the lifespan of the PV module and the energy output from the PV system.Due to the superior thermal heat properties of nanofluids,their usage in such systems has become increasingly widespread.Life cycle metrics which include Energy Payback period,Energy Production Factor and life cycle conversion efficiency were evaluated for the PVT system by exhaustively chalking fundamental parameters such as embodied energy of the PVT setup and the total energy output from the PVT system.This research aims to be a major milestone in the evolutionary journey of Photovoltaic Thermal modules by guiding the engineers working on the theory,design and implementation of PVT systems towards its economic feasibility,environmental impact and energy sustainability. 展开更多
关键词 Photovoltaic thermal system nanofluids performance parameters life cycle assessment
下载PDF
Effect of thermal load on performance parameters of solar concentrating photovoltaic:High-efficiency solar cells
6
作者 Ali.O.M.Maka Tadhg S O’Donovan 《Energy and Built Environment》 2022年第2期201-209,共9页
The triple-junction solar cell is designed to exploit a wide range of the solar spectrum photons.These triple-layers consisting of GaInP/GaInAs/Ge,it is monolithically stacked,leading to high conversion efficiency.To ... The triple-junction solar cell is designed to exploit a wide range of the solar spectrum photons.These triple-layers consisting of GaInP/GaInAs/Ge,it is monolithically stacked,leading to high conversion efficiency.To describe and understand it’s operating behaviour,this paper presents a performance analysis of a triple-junction solar cell,based on estimation modelling.A model was developed to determine the performance characteristic of the solar cell.Hence,the J-V curve is characterising the performance of solar cells,which used to optimise and improve the design of the cells.It has been discussed the effects of thermal load related to cell temperature increases on the cell’s operating performance parameters.Cell temperature increases from 25 to 125℃ have resulted variances,which causes a significant decrease in efficiency to approximately−17%,open circuit voltage by−15%and fill factor by−4.5%.On the other hand,the current density slightly increased by+5.5%.Finally,ought to consider the thermal management while designing and developing solar CPV technology;therefore,it’s significant to improve cell efficiency and to maintain cell integrity from thermal damage. 展开更多
关键词 performance parameters Temperature rises Triple-junction solar cells performance analysis Cell temperature
下载PDF
Effect of flue gas outlet temperature in evaporator on thermal economic performance of organic Rankine cycle system for sinter waste heat recovery
7
作者 Jun-sheng Feng Xin-ni Cheng +2 位作者 Huan-huan Wang Liang Zhao Hui Dong 《Journal of Iron and Steel Research(International)》 SCIE EI CAS CSCD 2023年第12期2378-2390,共13页
In order to improve the recovery and utilization rates of sinter waste heat effectively,the organic Rankine cycle(ORC)system with subcritical cycle was designed to recover the low-temperature sinter cooling flue gas w... In order to improve the recovery and utilization rates of sinter waste heat effectively,the organic Rankine cycle(ORC)system with subcritical cycle was designed to recover the low-temperature sinter cooling flue gas waste heat in an annular cooler for power generation.The thermodynamic,economic and multi-objective optimization models of ORC system were established,and R600a was selected as the ORC working medium.Subsequently,the variations in system thermodynamic performance and economic performance with the ORC thermal parameters were discussed in detail,and the optimal ORC thermal parameters were determined.The results show that the system net output power increases with increasing the evaporation temperature and decreasing the condensation temperature and increases first and then,decreases with the increase in superheat degree for a given flue gas outlet temperature in the evaporator,while the heat transfer area per unit net output power appears different variation trends in various ranges of flue gas outlet temperature.Taking the sinter cooling flue gas waste heat of 160℃as the ORC heat source,the optimal thermal parameters of ORC system were the flue gas outlet temperature of 90℃,the evaporation temperature of 95℃,the superheat degree of 10℃,and the condensation temperature of 28℃. 展开更多
关键词 Sinter.Waste heat recovery Organic Rankine cycle performance analysis:parameter optimization:Fluegasoutlettemperature
原文传递
Optimization and comparative performance analysis of conventional and desiccant air conditioning systems regenerated by two different modes for hot and humid climates:Experimental investigation
8
作者 Taliv Hussain 《Energy and Built Environment》 2023年第3期281-296,共16页
A desiccant air conditioning system is considered a capable alternative to a conventional air conditioning system because of its independent control of temperature,humidity and being eco-friendly.Also,to resolve the p... A desiccant air conditioning system is considered a capable alternative to a conventional air conditioning system because of its independent control of temperature,humidity and being eco-friendly.Also,to resolve the problem of more energy consumption for the restoration of a desiccant,structures comprising of desiccant can utilize thermal energy or complete waste heat to revive desiccant material.Therefore,this research work executes an experimental,optimization and comparative examination for conventional and desiccant air conditioning sys-tems regenerated by two different modes,i.e.firstly using(Mode-I)complete waste heat from condenser and secondly using(Mode-II)rod(electric heater)heat for regeneration at different process air inlet temperatures,i.e.(28,29.5,31,32.5,34,35.5 and 37°C),at different process air inlet velocities,i.e.(1.5,2.5,3.5 and 4.5 m/s)and a fix(2.5 m/s)regeneration air inlet velocity.Thus,optimization of performance parameters,i.e.VCOP,ECOP,dehumidification effectiveness,moisture removal capacity(kg/hr),DCOP,regeneration effectiveness and regeneration rate(kg/hr),is identified for achieving maximum efficiency of conventional and desiccant air con-ditioning systems under the above operating conditions. 展开更多
关键词 Conventional air conditioning system Desiccant air conditioning system Mode-I Mode-II Optimization and performance parameters
下载PDF
Measuring the spatial quality of bedrooms in nursing homes with visual environmental performance 被引量:1
9
作者 Dake Wei Xi Li 《Frontiers of Architectural Research》 CSCD 2021年第2期332-350,共19页
The elderly's perception of their environment largely depends on acquired visual information.This study provides a quantitative analytical method for designing bedrooms in nursing homes by developing a computation... The elderly's perception of their environment largely depends on acquired visual information.This study provides a quantitative analytical method for designing bedrooms in nursing homes by developing a computational model that uses viewing distance,viewing angle,and viewing field as variables.The model is utilized to measure a range of visual environmental properties,including privacy,accessibility,permeability,and visibility,which reflect the quality of bedrooms in nursing homes.The suitability levels of bedroom planes for the elderly and their main living functions as well as the fitting degree of the functional layout are calculated based on these data.After validating the computational moders feasibility,this study optimizes the typical schemes of single and double rooms in nursing homes.Results reveal certain advantages of the arrangement where bathroom doors are set toward the inside of the bedroom and double rooms have a large width.The computational model can be used in measuring the spatial quality of bedrooms in nursing homes and as a mathematical model for related algorithm design and software programming to assist in the design and optimization of bedrooms for the elderly. 展开更多
关键词 Nursing home Elderly bedroom Spatial quality Visual environment Computational model performance parameters
原文传递
Energy, economic and environmental performance assessment of a grid-tied rooftop system in different cities of India based on 3E analysis 被引量:1
10
作者 Anupama Khare Saxena Seema Saxena KSudhakar 《Clean Energy》 EI 2021年第2期288-301,共14页
India is very rich in solar energy,with a total of 3000 sunshine hours annually in most places.The installation of on-grid rooftop electricity-generation photovoltaic(PV)systems is currently undergoing substantial gro... India is very rich in solar energy,with a total of 3000 sunshine hours annually in most places.The installation of on-grid rooftop electricity-generation photovoltaic(PV)systems is currently undergoing substantial growth and extension as an alternate source of energy that contributes to Indian buildings.This paper analyses the viability of mounting solar PV plants in distinct cities of India in various locations with different climate conditions such as Delhi,Bhopal,Udaipur,Ahmadabad,Thiruvananthapuram,Pune and Madurai.The technical feasibility of installing a 100-kWp system is evaluated using PVsyst software under local climatic conditions.The performance ratio is between 70%and 80%,with a capacity utilization factor of 19-21%and estimated energy output of 170 MWh annually at all sites.The system produces 400-500 kWh of energy daily at a per-unit cost of INR 6-7(Indian rupees)in all locations.The lifespan of the system is~25-30 years,reducing about 150-170 tons of carbon-dioxide emission to the atmosphere every year.The payback period of the system is~5-6 years,which defines its feasibility.This information would encourage organizations and individuals to install such PV plants on the rooftops of buildings to use solar electricity for meeting the energy demands of the country. 展开更多
关键词 technical analysis solar photovoltaic system plant feasibility grid-connected system performance parameters
原文传递
Mass transfer mechanisms in fixed-bed adsorption of erythromycin 被引量:2
11
作者 Ying SUN Jiawen ZHU +2 位作者 Kui CHEN Sheng ZHU Jie XU 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2008年第4期353-360,共8页
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa... The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients. 展开更多
关键词 fixed-bed adsorption superficial velocity ionic strength erythromycin However investigations on the parameters governing the performance of this technology are still scarce.In the present work a polymeric and porous resin Sepabeads SP825 resin was used for its higher adsorption efficiency compared with the resins reported.The equilib-rium capacity of Sepabeads SP825 for EM in a batch system was established using a Langmuir isotherm.The effects of superficial velocity ionic strength and pH on the adsorption process were determined from the results of fixed bed experiments.And a model of the purification process was used to simulate the mass transfer mechanism which has taken film mass transfer pore diffusion and axial dispersion into account.The experimental adsorp-tion measurements were compared to the results calcu-lated from the model.The completion of these studies provide some essential parameters which are required in order to design a successful purification process and better understand the fundamentals of these process.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部