The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and wei...The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and weighted curve fitting method were presented to make the calculation more simple and accurate. The vertical scales of fluctuation of typical layers of Tianjin Port were calculated based on a number of engineering geotechnical investigation data, which can be guidance to other projects in this area. Meanwhile, the influences of sample interval and type of soil index on the scale of fluctuation were analyzed, according to which, the principle of determining the scale of fluctuation when the sample interval changes was defined. It can be obtained that the scale of fluctuation is the basic attribute reflecting spatial variability of soil, therefore, the scales of fluctuation calculated according to different soil indexes should be basically the same. The non-correlation distance method was improved, and the principle of determining the variance reduction function was also discussed.展开更多
Idealized cycles of refrigerating machines with adiabatic and isothermal compression of refrigerant vapor were investigated. Energetic characteristics of cycles： specific mass and volume cooling capacity q0 and qv, w...Idealized cycles of refrigerating machines with adiabatic and isothermal compression of refrigerant vapor were investigated. Energetic characteristics of cycles： specific mass and volume cooling capacity q0 and qv, work of compression 1, refrigerating coefficient of performance e and power N for drive of compressor were compared. These characteristics were calculated for eight refrigerants at temperature of their condensation 30 ℃ and temperatures of boiling -15℃ and -30 ℃. The calculations show that the use of isothermal compression of refrigerant vapor ensures economy of energy during refrigerating machine operation.展开更多
This article discusses the physical principles to be considered in a thermodynamic engineering solar system running under operational control algorithms designed to minimize entropy rates. The proposed plant is based ...This article discusses the physical principles to be considered in a thermodynamic engineering solar system running under operational control algorithms designed to minimize entropy rates. The proposed plant is based on scientific foundations established by thermodynamics and classical field theory, and empirical disciplines that deal with properties of chemical elements and with technologies of calorific capture from remote sources. The gauge principle was applied in theoretical formalization as an essential tool in the control background of the entropy rates involved. The industrial system presented was planned to recycle condensed matter within the scope of a solid waste management policy.展开更多
Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely us...Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD （Computational Fluid Dynamics） soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.展开更多
基金Supported by the National Natural Science Foundation of China(No.41272323)Tianjin Natural Science Foundation(No.13JCZDJC 35300)
文摘The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and weighted curve fitting method were presented to make the calculation more simple and accurate. The vertical scales of fluctuation of typical layers of Tianjin Port were calculated based on a number of engineering geotechnical investigation data, which can be guidance to other projects in this area. Meanwhile, the influences of sample interval and type of soil index on the scale of fluctuation were analyzed, according to which, the principle of determining the scale of fluctuation when the sample interval changes was defined. It can be obtained that the scale of fluctuation is the basic attribute reflecting spatial variability of soil, therefore, the scales of fluctuation calculated according to different soil indexes should be basically the same. The non-correlation distance method was improved, and the principle of determining the variance reduction function was also discussed.
文摘Idealized cycles of refrigerating machines with adiabatic and isothermal compression of refrigerant vapor were investigated. Energetic characteristics of cycles： specific mass and volume cooling capacity q0 and qv, work of compression 1, refrigerating coefficient of performance e and power N for drive of compressor were compared. These characteristics were calculated for eight refrigerants at temperature of their condensation 30 ℃ and temperatures of boiling -15℃ and -30 ℃. The calculations show that the use of isothermal compression of refrigerant vapor ensures economy of energy during refrigerating machine operation.
文摘This article discusses the physical principles to be considered in a thermodynamic engineering solar system running under operational control algorithms designed to minimize entropy rates. The proposed plant is based on scientific foundations established by thermodynamics and classical field theory, and empirical disciplines that deal with properties of chemical elements and with technologies of calorific capture from remote sources. The gauge principle was applied in theoretical formalization as an essential tool in the control background of the entropy rates involved. The industrial system presented was planned to recycle condensed matter within the scope of a solid waste management policy.
文摘Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD （Computational Fluid Dynamics） soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.
