Frequent extreme heat events around the world not only pose a major threat to human health but also cause significant economic losses to the livestock industry.The existing management practices are insufficient to ful...Frequent extreme heat events around the world not only pose a major threat to human health but also cause significant economic losses to the livestock industry.The existing management practices are insufficient to fully prevent heat stress with an urgent need to develop preventive medicines.The aim of this study was to develop an antiheat stress Chinese herbal formula(CHF)via big data analysis techniques and to evaluate its anti-heat stress effect and mechanism of action via pharmacodynamic evaluation and network pharmacology analysis.Many anti-heat stress CHFs were collected from the Chinese National Knowledge Infrastructure(CNKI)database.Three alternative CHFs were obtained via unsupervised entropy hierarchical clustering analysis,and the most effective CHF against heat stress,Shidi Jieshu decoction(SJD),was obtained by screening in a mouse heat stress model.In dry and hot environments,SJD significantly improved the heat tolerance of AA broilers by 4-6℃.In a humid and hot environment,pretreatment with 2%SJD resulted in 100%survival of Wenchang chickens at high temperatures.The main active ingredients of SJD were identified as muntjacoside E,timosaponin C,macrostemonoside H and mangiferin via ultraperformance liquid chromatography/mass spectrometry(UPLC/MS)and database comparison.The active ingredients of SJD were found to target tumor necrosis factor-α(TNF-α),signal transducer activator of transcription 3(STAT3)and epidermal growth factor receptor(EGFR).Finally,the safety of the new formulation was assessed in an acute oral toxicity study in rats.The SJDs developed in this study provide a new option for the prevention of heat stress in animal husbandry and offer new insights for further research on anti-heat stress.展开更多
The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,w...The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,which has significant applications in heat exchangers and engineering devices.To optimize heat transfer,a liquid film of Cu and TiO_(2)hybrid nanofluid behind a stretching sheet in a variable porous medium is being considered due to its importance.The nature of the fluid is considered time-dependent and the thickness of the liquid film is measured variable adjustable with the variable porous space and favorable for the uniform flow of the liquid film.The solution of the problem is acquired using the homotopy analysis method HAM,and the artificial neural network ANN is applied to obtain detailed information in the form of error estimation and validations using the fitting curve analysis.HAM data is utilized to train the ANN in this study,which uses Cu and TiO_(2)hybrid nanofluids in a variable porous space for unsteady thin film flow,and it is used to train the ANN.The results indicate that Cu and TiO_(2)play a greater role in boosting the rate.展开更多
The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and p...The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.展开更多
In order to investigate the leak detection strategy of a heating network,a space-based simulation mathematical model for the heating network under leakage conditions is built by graph theory.The pressure changes of al...In order to investigate the leak detection strategy of a heating network,a space-based simulation mathematical model for the heating network under leakage conditions is built by graph theory.The pressure changes of all the nodes in the heating network are obtained from node leak and pipe leak conditions.Then,a leakage diagnosis system based on the back propagation（BP）neural network is established.This diagnosis system can predict the leakage pipe by collecting the pressure change data of the monitoring points,which can preliminary estimate the leak location.The usefulness of this system is proved by an example.The experimental results show that the forecast accuracy by this diagnosis system can reach 100%.展开更多
The complex network of fractures formed by randomly distributed natural fractures in hot-dry rocks(HDRs)complicates the heat transfer regularity of injected fluid.On the basis of the fracture network,exploring the cha...The complex network of fractures formed by randomly distributed natural fractures in hot-dry rocks(HDRs)complicates the heat transfer regularity of injected fluid.On the basis of the fracture network,exploring the characteristics of the fluid flow and heat transfer as influenced by different parameters helps enable efficient resource extraction and effectively promotes the construction of diversified energy utilization structures.Accordingly,accounting for the effect of the thermal shock on the evolution of the permeability of the rock matrix,a thermo-hydromechanical(THM)coupling model is developed to analyze the influences of fracture network characteristics on the heat extraction performance of HDRs.In addition,a large-scale injection and production physical simulation experiment is performed using a newly developed,in-house,large-scale true triaxial experimental system.The corresponding numerical model is established and validated.The good agreement between the numerical and experimental results verifies the reliability and accuracy of the proposed THM model.Subsequently,a two-dimensional model is established under complex fracture network conditions,taking,as a research object,the natural fracture characteristics of HDR in the Qinghai Gonghe Basin in combination with the regional geological information.The effects of different parameters,including the production well location,rock matrix permeability,injection rate,initial fracture width,and number of fractures,on the production temperature and heat extraction performance are systematically analyzed.The results indicate that an increase in the number of fractures,the distance between the injection well and the production well,or the width of the initial fractures leads to an improved heat extraction performance.The number of fractures increased from 11 horizontal fractures and 22 high-angle fractures to 35 horizontal fractures and 70 high-angle fractures,with a 20%increase in heat extraction rate.While the influence of the rock matrix permeability is not highly significant,it cannot be ignored.It is crucial to select an injection rate that is neither too low nor too high,taking into consideration economic factors.展开更多
Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexib...Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexible pipes and further diffuse into the annular space,incurring annular pressure build-up and/or production of acidic environment,which poses serious challenges to the structure and integrity of the flexible pipes.Gas permeation in pipes is a complex phenomenon governed by various factors such as internal pressure and temperature,annular structure,external temperature.In a long-distance gas flexible pipe,moreover,gas permeation exhibits non-uniform features,and the gas permeated into the annular space flows along the metal gap.To assess the complex gas transport behavior in long-distance gas flexible pipes,a mathematical model is established in this paper considering the multiphase flow phenomena inside the flexible pipes,the diffusion of gas in the inner liner,and the gas seepage in the annular space under varying permeable properties of the annulus.In addition,the effect of a variable temperature is accounted.A numerical calculation method is accordingly constructed to solve the coupling mathematical equations.The annular permeability was shown to significantly influence the distribution of annular pressure.As permeability increases,the annular pressure tends to become more uniform,and the annular pressure at the wellhead rises more rapidly.After annular pressure relief followed by shut-in,the pressure increase follows a convex function.By simulating the pressure recovery pattern after pressure relief and comparing it with test results,we deduce that the annular permeability lies between 123 and 512 m D.The results help shed light upon assessing the annular pressure in long distance gas flexible pipes and thus ensure the security of gas transport in the emerging development of offshore resources.展开更多
The traditional methods for synthesizing flexible heat exchanger networks(HENs)are not directly applicable to inter-plant HEN challenges,primarily due to the spread of system uncertainty across plants via intermedium ...The traditional methods for synthesizing flexible heat exchanger networks(HENs)are not directly applicable to inter-plant HEN challenges,primarily due to the spread of system uncertainty across plants via intermedium fluid circles.This complicates the synthesis process significantly.To tackle this issue,this study proposes a decomposed stepwise methodology to facilitate the flexible synthesis of the interplant HENs performing indirect heat integration.A decomposition strategy is proposed to divide the overall network into manageable sub-networks by dissecting the intermedium fluid circles.To address the variability in intermedium fluid temperatures,a temperature fluctuation analysis approach is developed and a heuristic rule is introduced to maintain the temperature feasibility of the intermedium fluids.To ensure adequate flexibility and cost-effectiveness of the designed networks,flexibility analysis and network retrofit steps are conducted through model-based optimization techniques.The efficacy of the method is demonstrated through two case studies,showing its potential in achieving the desired operational flexibility for inter-plant HENs.展开更多
Heat integration is important for energy-saving in the process industry.It is linked to the persistently challenging task of optimal design of heat exchanger networks(HEN).Due to the inherent highly nonconvex nonlinea...Heat integration is important for energy-saving in the process industry.It is linked to the persistently challenging task of optimal design of heat exchanger networks(HEN).Due to the inherent highly nonconvex nonlinear and combinatorial nature of the HEN problem,it is not easy to find solutions of high quality for large-scale problems.The reinforcement learning(RL)method,which learns strategies through ongoing exploration and exploitation,reveals advantages in such area.However,due to the complexity of the HEN design problem,the RL method for HEN should be dedicated and designed.A hybrid strategy combining RL with mathematical programming is proposed to take better advantage of both methods.An insightful state representation of the HEN structure as well as a customized reward function is introduced.A Q-learning algorithm is applied to update the HEN structure using theε-greedy strategy.Better results are obtained from three literature cases of different scales.展开更多
in order to verify the heat-tolerance effect, two trainings, 90 min marching with load (WBGT 24. 6～35.6℃) and 10 km running (WBGT 25.0～31.1℃) were performed in laboratory and field under hot climate.Ten to twelve ...in order to verify the heat-tolerance effect, two trainings, 90 min marching with load (WBGT 24. 6～35.6℃) and 10 km running (WBGT 25.0～31.1℃) were performed in laboratory and field under hot climate.Ten to twelve times (days) of training were carried out展开更多
The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)model.The governing dimensional temperature equations for the solid and fluid phases of the porous extended surfa...The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)model.The governing dimensional temperature equations for the solid and fluid phases of the porous extended surface are modeled,and then are nondimensionalized by suitable dimensionless terms.Further,the obtained nondimensional equations are solved by the clique polynomial method(CPM).The effects of several dimensionless parameters on the fin's thermal profiles are shown by graphical illustrations.Additionally,the current study implements deep neural structures to solve physics-governed coupled equations,and the best-suited hyperparameters are attained by comparison with various network combinations.The results of the CPM and physicsinformed neural network(PINN)exhibit good agreement,signifying that both methods effectively solve the thermal modeling problem.展开更多
The heating technological requirement of the conventional PID control is difficult to guarantee which based on the precise mathematical model,because the heating furnace for heating treatment with the big inertia,the ...The heating technological requirement of the conventional PID control is difficult to guarantee which based on the precise mathematical model,because the heating furnace for heating treatment with the big inertia,the pure time delay and nonlinear time-varying.Proposed one kind optimized variable method of PID controller based on the genetic algorithm with improved BP network that better realized the completely automatic intelligent control of the entire thermal process than the classics critical purporting(Z-N)method.A heating furnace for the object was simulated with MATLAB,simulation results show that the control system has the quicker response characteristic,the better dynamic characteristic and the quite stronger robustness,which has some promotional value for the control of industrial furnace.展开更多
Objective:This study investigates the effects of ginger on sperm dysmorphosis under heat stress using network pharmacology and molecular docking techniques.Methods:The core components,target sites,and primary pathways...Objective:This study investigates the effects of ginger on sperm dysmorphosis under heat stress using network pharmacology and molecular docking techniques.Methods:The core components,target sites,and primary pathways of ginger were predicted using the TCMSP database.Genes associated with sperm malformation and heat stress were identified through databases such as GeneCards and DisGeNET,followed by KEGG and GO analyses based on intersections with ginger targets.Core genes identified via Cytoscape software were subjected to molecular docking with ginger’s active components.Results:The principal active components of ginger identified includeβ-sitosterol and dihydrocapsaicin.Network pharmacology analysis suggested that ginger exerts its effects through pathways such as the prostate cancer signaling pathway,estrogen signaling pathway,inflammatory pathways,and nuclear receptor signal transduction.These pathways may ameliorate sperm malformation symptoms caused by heat stress.Conclusion:Integrating findings from network pharmacology and molecular docking,the active components of ginger potentially modulate the expression of heat shock proteins during heat stress via inflammatory and oxidative stress pathways.This modulation may protect spermatogenesis under heat stress and improve sperm malformation.展开更多
In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fu...In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fuels of the system,including coal and gas,would cause different environmental impacts. Meanwhile,the reliability of the heating networks would be changed because the peak load regulating boiler could work as a standby heat source. A model for assessment of heating system was established by value analysis to optimize this kind of system. Energy consumption,greenhouse gas emission,pollution emission and system reliability were selected as functional assessment indexes in the model. Weights of each function were determined by analytical hierarchy process (AHP) and experts consultation. Life cycle cost was used as the cost in the model. A real case as an example was discussed to obtain the optimal base load ratio. The result shows that the optimal base load ratio of the case is 0.77.展开更多
As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness dis...As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness distribution functions of the Bakhtiary dam site and Oskarshamn/Forsmark mountain were fitted using statistical methods.The COMSOL Multiphysics finite element software was utilized to analyze the effects of fracture roughness distribution types and empirical formulas for fracture hydraulic aperture on the seepage field and temperature field of rock masses.The results show that:(1)The fracture roughness at the Bakhtiary dam site and Oskarshamn/Forsmark mountain follows lognormal and normal distributions,respectively;(2)For rock masses with the same expected value and standard deviation of fracture roughness,the outflow from rock masses with lognormal distribution of fracture roughness is significantly larger than that of rock masses with normal distribution of fracture roughness;(3)The fracture hydraulic aperture,outflow,and cold front distance of the Li and Jiang model are significantly larger than those of the Barton model;(4)The outflow,hydraulic pressure distribution,and temperature distribution of the Barton model are more sensitive to the fracture roughness distribution type than those of the Li and Jiang model.展开更多
The experimental analysis takes too much time-consuming process and requires considerable effort,while,the Artificial Neural Network(ANN)algorithms are simple,affordable,and fast,and they allow us to make a relevant a...The experimental analysis takes too much time-consuming process and requires considerable effort,while,the Artificial Neural Network(ANN)algorithms are simple,affordable,and fast,and they allow us to make a relevant analysis in establishing an appropriate relationship between the input and output parameters.This paper deals with the use of back-propagation ANN algorithms for the experimental data of heat transfer coefficient,Nusselt number,and friction factor of water-based Fe_(3)O_(4)-TiO_(2) magnetic hybrid nanofluids in a mini heat sink under magnetic fields.The data considered for the ANN network is at different Reynolds numbers(239 to 1874),different volume concentrations(0%to 2.0%),and different magnetic fields(250 to 1000 G),respectively.Three types of ANN back-propagation algorithms Levenberg-Marquardt(LM),Broyden-Fletcher-Goldfarb-Shanno Quasi Newton(BFGS),and Variable Learning Rate Gradient Descent(VLGD)were used to train the heat transfer coefficient,Nusselt number,and friction factor data,respectively.The ANOVA t-test analysis was also performed to determine the relative accuracy of the three ANN algorithms.The Nusselt number of 2.0%vol.of Fe_(3)O_(4)-TiO_(2) hybrid nanofluid is enhanced by 38.16%without a magnetic field,and it is further enhanced by 88.93%with the magnetic field of 1000 Gauss at a Reynolds number of 1874,with respect to the base fluid.A total of 126 datasets of heat transfer coefficient,Nusselt number,and friction factor were used as input and output data.The three ANN algorithms of LM,BFGS,and VLGD,have shown good acceptance with the experimental data with root-mean-square errors of 0.34883,0.25341,and 1.0202 with correlation coefficients(R2)of 0.99954,0.9967,and 0.94501,respectively,for the Nusselt number data.Moreover,the three ANN algorithms predict root-mean-square errors of 0.001488,0.005041,and 0.006924 with correlation coefficients(R2)of 0.99982,0.99976,and 0.99486,respectively,for the friction factor data.Compared to BFGS and VLGD algorithms,the LM algorithm predicts high accuracy for Nusselt number,and friction factor data.The proposed Nusselt number and friction factor correlations are also discussed.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
In this paper,a data-driven topology optimization(TO)method is proposed for the efficient design of three-dimensional heat transfer structures.The presented method is composed of four parts.Firstly,the three-dimension...In this paper,a data-driven topology optimization(TO)method is proposed for the efficient design of three-dimensional heat transfer structures.The presented method is composed of four parts.Firstly,the three-dimensional heat transfer topology optimization(HTTO)dataset,composed of both design parameters and the corresponding HTTO configuration,is established by the solid isotropic material with penalization(SIMP)method.Secondly,a high-performance surrogate model,named ResUNet-assisted generative adversarial nets(ResUNet-GAN),is developed by combining ReUNet and generative and adversarial nets(GAN).Thirdly,the same-resolution(SR)ResUNet-GAN is deployed to design three-dimensional heat transfer configurations by feeding design parameters.Finally,the finite element mesh of the optimized configuration is refined by the cross-resolution(CR)ResUNet-GAN to obtain near-optimal three-dimensional heat transfer configurations.Compared with conventional TO methods,the proposed method has two outstanding advantages:(1)the developed surrogate model establishes the end-to-end mapping from the design parameters to the three-dimensional configuration without any need for optimization iterations and finite element analysis;(2)both the SR ResUNet-GAN and the CR ResUNet-GAN can be employed individually or in combination to achieve each function,according to the needs of heat transfer structures.The data-driven method provides an efficient design framework for three-dimensional practical engineering problems.展开更多
The upgrading of the DH （district heating） system through installing WSN （wireless sensor networks）--a technology by which to monitor and control quality operation of the DH system will lead to more effective use ...The upgrading of the DH （district heating） system through installing WSN （wireless sensor networks）--a technology by which to monitor and control quality operation of the DH system will lead to more effective use of thermal energy, enabling also the provision of quality customer services, as the data concerning the status of the existing networks is available in a timely manner, and in the stated amounts. Over the last decades, the use of WSN systems in enabling quality monitoring of heat production and supply process has been widely discussed among various researchers and industry experts, but has been little deployed in practice. These researchers and industry experts have analysed the advantages and constraints related to the use of the WSN in district heating. A pilot project conducted by Riga Heat （the main heating supplier in Riga, Latvia） has allowed to gain a real life experience as to the use of the WSN system in district in-house heating substations, and is deemed to be a major step towards future development of WSN technologies.展开更多
Since the reform and opening up, China's economic level has gradually improved, and people’s demand for a better life has become increasingly strong. With the rapid development of urbanization, large-scale popula...Since the reform and opening up, China's economic level has gradually improved, and people’s demand for a better life has become increasingly strong. With the rapid development of urbanization, large-scale population and construction facilities gather in the city. Heat energy is an essential energy in people’s life. Central heating engineering has become an essential infrastructure in urban construction. At the same time, heating engineering also implements the strategy of human sustainable development, which is important for improving people’s living standards, protecting the environment and improving the environment. The present situation of gas reservoir plays an important role. The construction of heat pipe network in the city is relatively strict. In order to avoid that the heat pipe network project will affect the interests of residents, public safety and the stability of the whole system due to quality problems, the relevant parties of the project should conduct real-time supervision and inspection according to relevant standards during the construction of facilities. The design documents should be implemented to ensure the scientificity, safety and stability of the project. And improve the efficiency of its system operation, to achieve the purpose of economic operation. This paper makes a detailed analysis and discussion on the importance of the safety construction of the heat pipe network project and the supervision in the construction process, so as to lay a theoretical foundation for the smooth progress of the project.展开更多
The sustainable development of Chinas social economy, the heating pipe network project has also had a great development. At present, the society gives positive encouragement and advocacy to the sustainable development...The sustainable development of Chinas social economy, the heating pipe network project has also had a great development. At present, the society gives positive encouragement and advocacy to the sustainable development of the project, and takes energy conservation and emission reduction as a very important task at present. Environmental protection has also become the primary factor of project construction. Central heating has been gradually adopted by construction workers in the heat network, mainly because central heating can greatly reduce the cost of the project. But if there is a problem in a node in the heat network, it will lead to a large area of the heat network without heating phenomenon. Therefore, due to the complex pipe network, the quality danger of heating pipe network is easy to occur in the construction process. Strengthening the construction technology is an important basis to ensure the quality.展开更多
基金supported by the Major Special Science and Technology Plan(202302AA310020)the National Natural Science Foundation of China(NSFC)(32072925,32473087)the National Student Innovation and Entrepreneurship Training Program of Huazhong Agricultural University(202310504018)。
文摘Frequent extreme heat events around the world not only pose a major threat to human health but also cause significant economic losses to the livestock industry.The existing management practices are insufficient to fully prevent heat stress with an urgent need to develop preventive medicines.The aim of this study was to develop an antiheat stress Chinese herbal formula(CHF)via big data analysis techniques and to evaluate its anti-heat stress effect and mechanism of action via pharmacodynamic evaluation and network pharmacology analysis.Many anti-heat stress CHFs were collected from the Chinese National Knowledge Infrastructure(CNKI)database.Three alternative CHFs were obtained via unsupervised entropy hierarchical clustering analysis,and the most effective CHF against heat stress,Shidi Jieshu decoction(SJD),was obtained by screening in a mouse heat stress model.In dry and hot environments,SJD significantly improved the heat tolerance of AA broilers by 4-6℃.In a humid and hot environment,pretreatment with 2%SJD resulted in 100%survival of Wenchang chickens at high temperatures.The main active ingredients of SJD were identified as muntjacoside E,timosaponin C,macrostemonoside H and mangiferin via ultraperformance liquid chromatography/mass spectrometry(UPLC/MS)and database comparison.The active ingredients of SJD were found to target tumor necrosis factor-α(TNF-α),signal transducer activator of transcription 3(STAT3)and epidermal growth factor receptor(EGFR).Finally,the safety of the new formulation was assessed in an acute oral toxicity study in rats.The SJDs developed in this study provide a new option for the prevention of heat stress in animal husbandry and offer new insights for further research on anti-heat stress.
文摘The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,which has significant applications in heat exchangers and engineering devices.To optimize heat transfer,a liquid film of Cu and TiO_(2)hybrid nanofluid behind a stretching sheet in a variable porous medium is being considered due to its importance.The nature of the fluid is considered time-dependent and the thickness of the liquid film is measured variable adjustable with the variable porous space and favorable for the uniform flow of the liquid film.The solution of the problem is acquired using the homotopy analysis method HAM,and the artificial neural network ANN is applied to obtain detailed information in the form of error estimation and validations using the fitting curve analysis.HAM data is utilized to train the ANN in this study,which uses Cu and TiO_(2)hybrid nanofluids in a variable porous space for unsteady thin film flow,and it is used to train the ANN.The results indicate that Cu and TiO_(2)play a greater role in boosting the rate.
基金Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization(South China University of Technology)(2013A061401005)Research Fund(JMSWFW-2110-044)from Zhongshan Jiaming Electric Power Co.,Ltd.
文摘The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.
基金The National Natural Science Foundation of China(No.50378029)
文摘In order to investigate the leak detection strategy of a heating network,a space-based simulation mathematical model for the heating network under leakage conditions is built by graph theory.The pressure changes of all the nodes in the heating network are obtained from node leak and pipe leak conditions.Then,a leakage diagnosis system based on the back propagation（BP）neural network is established.This diagnosis system can predict the leakage pipe by collecting the pressure change data of the monitoring points,which can preliminary estimate the leak location.The usefulness of this system is proved by an example.The experimental results show that the forecast accuracy by this diagnosis system can reach 100%.
基金supported by the Major Program of National Natural Science Foundation of China(No.52192622)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(No.SKLGP2022Z018).
文摘The complex network of fractures formed by randomly distributed natural fractures in hot-dry rocks(HDRs)complicates the heat transfer regularity of injected fluid.On the basis of the fracture network,exploring the characteristics of the fluid flow and heat transfer as influenced by different parameters helps enable efficient resource extraction and effectively promotes the construction of diversified energy utilization structures.Accordingly,accounting for the effect of the thermal shock on the evolution of the permeability of the rock matrix,a thermo-hydromechanical(THM)coupling model is developed to analyze the influences of fracture network characteristics on the heat extraction performance of HDRs.In addition,a large-scale injection and production physical simulation experiment is performed using a newly developed,in-house,large-scale true triaxial experimental system.The corresponding numerical model is established and validated.The good agreement between the numerical and experimental results verifies the reliability and accuracy of the proposed THM model.Subsequently,a two-dimensional model is established under complex fracture network conditions,taking,as a research object,the natural fracture characteristics of HDR in the Qinghai Gonghe Basin in combination with the regional geological information.The effects of different parameters,including the production well location,rock matrix permeability,injection rate,initial fracture width,and number of fractures,on the production temperature and heat extraction performance are systematically analyzed.The results indicate that an increase in the number of fractures,the distance between the injection well and the production well,or the width of the initial fractures leads to an improved heat extraction performance.The number of fractures increased from 11 horizontal fractures and 22 high-angle fractures to 35 horizontal fractures and 70 high-angle fractures,with a 20%increase in heat extraction rate.While the influence of the rock matrix permeability is not highly significant,it cannot be ignored.It is crucial to select an injection rate that is neither too low nor too high,taking into consideration economic factors.
基金supported by the Natural Science Research Project of Guangling College of Yangzhou University,China (ZKZD18004)General Program of Natural Science Research in Higher Education Institutions of Jiangsu Province,China (20KJD430006)。
文摘Gas flexible pipes are critical multi-layered equipment for offshore oil and gas development.Under high pressure conditions,small molecular components of natural gas dissolve into the polymer inner liner of the flexible pipes and further diffuse into the annular space,incurring annular pressure build-up and/or production of acidic environment,which poses serious challenges to the structure and integrity of the flexible pipes.Gas permeation in pipes is a complex phenomenon governed by various factors such as internal pressure and temperature,annular structure,external temperature.In a long-distance gas flexible pipe,moreover,gas permeation exhibits non-uniform features,and the gas permeated into the annular space flows along the metal gap.To assess the complex gas transport behavior in long-distance gas flexible pipes,a mathematical model is established in this paper considering the multiphase flow phenomena inside the flexible pipes,the diffusion of gas in the inner liner,and the gas seepage in the annular space under varying permeable properties of the annulus.In addition,the effect of a variable temperature is accounted.A numerical calculation method is accordingly constructed to solve the coupling mathematical equations.The annular permeability was shown to significantly influence the distribution of annular pressure.As permeability increases,the annular pressure tends to become more uniform,and the annular pressure at the wellhead rises more rapidly.After annular pressure relief followed by shut-in,the pressure increase follows a convex function.By simulating the pressure recovery pattern after pressure relief and comparing it with test results,we deduce that the annular permeability lies between 123 and 512 m D.The results help shed light upon assessing the annular pressure in long distance gas flexible pipes and thus ensure the security of gas transport in the emerging development of offshore resources.
基金financial support provided by the National Natural Science Foundation of China(22378045,22178045).
文摘The traditional methods for synthesizing flexible heat exchanger networks(HENs)are not directly applicable to inter-plant HEN challenges,primarily due to the spread of system uncertainty across plants via intermedium fluid circles.This complicates the synthesis process significantly.To tackle this issue,this study proposes a decomposed stepwise methodology to facilitate the flexible synthesis of the interplant HENs performing indirect heat integration.A decomposition strategy is proposed to divide the overall network into manageable sub-networks by dissecting the intermedium fluid circles.To address the variability in intermedium fluid temperatures,a temperature fluctuation analysis approach is developed and a heuristic rule is introduced to maintain the temperature feasibility of the intermedium fluids.To ensure adequate flexibility and cost-effectiveness of the designed networks,flexibility analysis and network retrofit steps are conducted through model-based optimization techniques.The efficacy of the method is demonstrated through two case studies,showing its potential in achieving the desired operational flexibility for inter-plant HENs.
基金The financial support provided by the Project of National Natural Science Foundation of China(U22A20415,21978256,22308314)“Pioneer”and“Leading Goose”Research&Development Program of Zhejiang(2022C01SA442617)。
文摘Heat integration is important for energy-saving in the process industry.It is linked to the persistently challenging task of optimal design of heat exchanger networks(HEN).Due to the inherent highly nonconvex nonlinear and combinatorial nature of the HEN problem,it is not easy to find solutions of high quality for large-scale problems.The reinforcement learning(RL)method,which learns strategies through ongoing exploration and exploitation,reveals advantages in such area.However,due to the complexity of the HEN design problem,the RL method for HEN should be dedicated and designed.A hybrid strategy combining RL with mathematical programming is proposed to take better advantage of both methods.An insightful state representation of the HEN structure as well as a customized reward function is introduced.A Q-learning algorithm is applied to update the HEN structure using theε-greedy strategy.Better results are obtained from three literature cases of different scales.
文摘in order to verify the heat-tolerance effect, two trainings, 90 min marching with load (WBGT 24. 6～35.6℃) and 10 km running (WBGT 25.0～31.1℃) were performed in laboratory and field under hot climate.Ten to twelve times (days) of training were carried out
基金funding this work through Small Research Project under grant number RGP.1/141/45。
文摘The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)model.The governing dimensional temperature equations for the solid and fluid phases of the porous extended surface are modeled,and then are nondimensionalized by suitable dimensionless terms.Further,the obtained nondimensional equations are solved by the clique polynomial method(CPM).The effects of several dimensionless parameters on the fin's thermal profiles are shown by graphical illustrations.Additionally,the current study implements deep neural structures to solve physics-governed coupled equations,and the best-suited hyperparameters are attained by comparison with various network combinations.The results of the CPM and physicsinformed neural network(PINN)exhibit good agreement,signifying that both methods effectively solve the thermal modeling problem.
基金This work was supported by the youth backbone teachers training program of Henan colleges and universities under Grant No.2016ggjs-287the project of science and technology of Henan province under Grant No.172102210124the Key Scientific Research projects in Colleges and Universities in Henan(Grant No.18B460003).
文摘The heating technological requirement of the conventional PID control is difficult to guarantee which based on the precise mathematical model,because the heating furnace for heating treatment with the big inertia,the pure time delay and nonlinear time-varying.Proposed one kind optimized variable method of PID controller based on the genetic algorithm with improved BP network that better realized the completely automatic intelligent control of the entire thermal process than the classics critical purporting(Z-N)method.A heating furnace for the object was simulated with MATLAB,simulation results show that the control system has the quicker response characteristic,the better dynamic characteristic and the quite stronger robustness,which has some promotional value for the control of industrial furnace.
基金Department of Science and Technology of Hunan Province(Project No.2024JJ8222)Double First-Class Bioengineering Applied Characteristic Disciplines in Higher Education in Hunan Province。
文摘Objective:This study investigates the effects of ginger on sperm dysmorphosis under heat stress using network pharmacology and molecular docking techniques.Methods:The core components,target sites,and primary pathways of ginger were predicted using the TCMSP database.Genes associated with sperm malformation and heat stress were identified through databases such as GeneCards and DisGeNET,followed by KEGG and GO analyses based on intersections with ginger targets.Core genes identified via Cytoscape software were subjected to molecular docking with ginger’s active components.Results:The principal active components of ginger identified includeβ-sitosterol and dihydrocapsaicin.Network pharmacology analysis suggested that ginger exerts its effects through pathways such as the prostate cancer signaling pathway,estrogen signaling pathway,inflammatory pathways,and nuclear receptor signal transduction.These pathways may ameliorate sperm malformation symptoms caused by heat stress.Conclusion:Integrating findings from network pharmacology and molecular docking,the active components of ginger potentially modulate the expression of heat shock proteins during heat stress via inflammatory and oxidative stress pathways.This modulation may protect spermatogenesis under heat stress and improve sperm malformation.
文摘In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fuels of the system,including coal and gas,would cause different environmental impacts. Meanwhile,the reliability of the heating networks would be changed because the peak load regulating boiler could work as a standby heat source. A model for assessment of heating system was established by value analysis to optimize this kind of system. Energy consumption,greenhouse gas emission,pollution emission and system reliability were selected as functional assessment indexes in the model. Weights of each function were determined by analytical hierarchy process (AHP) and experts consultation. Life cycle cost was used as the cost in the model. A real case as an example was discussed to obtain the optimal base load ratio. The result shows that the optimal base load ratio of the case is 0.77.
基金College Students Innovation and Entrepreneurship Project of Guangzhou Railway Polytechnic(2025CXCY015)。
文摘As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness distribution functions of the Bakhtiary dam site and Oskarshamn/Forsmark mountain were fitted using statistical methods.The COMSOL Multiphysics finite element software was utilized to analyze the effects of fracture roughness distribution types and empirical formulas for fracture hydraulic aperture on the seepage field and temperature field of rock masses.The results show that:(1)The fracture roughness at the Bakhtiary dam site and Oskarshamn/Forsmark mountain follows lognormal and normal distributions,respectively;(2)For rock masses with the same expected value and standard deviation of fracture roughness,the outflow from rock masses with lognormal distribution of fracture roughness is significantly larger than that of rock masses with normal distribution of fracture roughness;(3)The fracture hydraulic aperture,outflow,and cold front distance of the Li and Jiang model are significantly larger than those of the Barton model;(4)The outflow,hydraulic pressure distribution,and temperature distribution of the Barton model are more sensitive to the fracture roughness distribution type than those of the Li and Jiang model.
基金supported by the Recovery and Resilience Plan(PRR)and by European Funds Next Generation EU under the Project“AET—Alliance for Energy Transition,”no.C644914747-00000023,investment project no.56 of the Incentive System“Agendas for Business Innovation”.
文摘The experimental analysis takes too much time-consuming process and requires considerable effort,while,the Artificial Neural Network(ANN)algorithms are simple,affordable,and fast,and they allow us to make a relevant analysis in establishing an appropriate relationship between the input and output parameters.This paper deals with the use of back-propagation ANN algorithms for the experimental data of heat transfer coefficient,Nusselt number,and friction factor of water-based Fe_(3)O_(4)-TiO_(2) magnetic hybrid nanofluids in a mini heat sink under magnetic fields.The data considered for the ANN network is at different Reynolds numbers(239 to 1874),different volume concentrations(0%to 2.0%),and different magnetic fields(250 to 1000 G),respectively.Three types of ANN back-propagation algorithms Levenberg-Marquardt(LM),Broyden-Fletcher-Goldfarb-Shanno Quasi Newton(BFGS),and Variable Learning Rate Gradient Descent(VLGD)were used to train the heat transfer coefficient,Nusselt number,and friction factor data,respectively.The ANOVA t-test analysis was also performed to determine the relative accuracy of the three ANN algorithms.The Nusselt number of 2.0%vol.of Fe_(3)O_(4)-TiO_(2) hybrid nanofluid is enhanced by 38.16%without a magnetic field,and it is further enhanced by 88.93%with the magnetic field of 1000 Gauss at a Reynolds number of 1874,with respect to the base fluid.A total of 126 datasets of heat transfer coefficient,Nusselt number,and friction factor were used as input and output data.The three ANN algorithms of LM,BFGS,and VLGD,have shown good acceptance with the experimental data with root-mean-square errors of 0.34883,0.25341,and 1.0202 with correlation coefficients(R2)of 0.99954,0.9967,and 0.94501,respectively,for the Nusselt number data.Moreover,the three ANN algorithms predict root-mean-square errors of 0.001488,0.005041,and 0.006924 with correlation coefficients(R2)of 0.99982,0.99976,and 0.99486,respectively,for the friction factor data.Compared to BFGS and VLGD algorithms,the LM algorithm predicts high accuracy for Nusselt number,and friction factor data.The proposed Nusselt number and friction factor correlations are also discussed.
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.
基金supported by the National Natural Science Foundation of China(12472113,11872080)Natural Science Foundation of Beijing,China(3192005).
文摘In this paper,a data-driven topology optimization(TO)method is proposed for the efficient design of three-dimensional heat transfer structures.The presented method is composed of four parts.Firstly,the three-dimensional heat transfer topology optimization(HTTO)dataset,composed of both design parameters and the corresponding HTTO configuration,is established by the solid isotropic material with penalization(SIMP)method.Secondly,a high-performance surrogate model,named ResUNet-assisted generative adversarial nets(ResUNet-GAN),is developed by combining ReUNet and generative and adversarial nets(GAN).Thirdly,the same-resolution(SR)ResUNet-GAN is deployed to design three-dimensional heat transfer configurations by feeding design parameters.Finally,the finite element mesh of the optimized configuration is refined by the cross-resolution(CR)ResUNet-GAN to obtain near-optimal three-dimensional heat transfer configurations.Compared with conventional TO methods,the proposed method has two outstanding advantages:(1)the developed surrogate model establishes the end-to-end mapping from the design parameters to the three-dimensional configuration without any need for optimization iterations and finite element analysis;(2)both the SR ResUNet-GAN and the CR ResUNet-GAN can be employed individually or in combination to achieve each function,according to the needs of heat transfer structures.The data-driven method provides an efficient design framework for three-dimensional practical engineering problems.
文摘The upgrading of the DH （district heating） system through installing WSN （wireless sensor networks）--a technology by which to monitor and control quality operation of the DH system will lead to more effective use of thermal energy, enabling also the provision of quality customer services, as the data concerning the status of the existing networks is available in a timely manner, and in the stated amounts. Over the last decades, the use of WSN systems in enabling quality monitoring of heat production and supply process has been widely discussed among various researchers and industry experts, but has been little deployed in practice. These researchers and industry experts have analysed the advantages and constraints related to the use of the WSN in district heating. A pilot project conducted by Riga Heat （the main heating supplier in Riga, Latvia） has allowed to gain a real life experience as to the use of the WSN system in district in-house heating substations, and is deemed to be a major step towards future development of WSN technologies.
文摘Since the reform and opening up, China's economic level has gradually improved, and people’s demand for a better life has become increasingly strong. With the rapid development of urbanization, large-scale population and construction facilities gather in the city. Heat energy is an essential energy in people’s life. Central heating engineering has become an essential infrastructure in urban construction. At the same time, heating engineering also implements the strategy of human sustainable development, which is important for improving people’s living standards, protecting the environment and improving the environment. The present situation of gas reservoir plays an important role. The construction of heat pipe network in the city is relatively strict. In order to avoid that the heat pipe network project will affect the interests of residents, public safety and the stability of the whole system due to quality problems, the relevant parties of the project should conduct real-time supervision and inspection according to relevant standards during the construction of facilities. The design documents should be implemented to ensure the scientificity, safety and stability of the project. And improve the efficiency of its system operation, to achieve the purpose of economic operation. This paper makes a detailed analysis and discussion on the importance of the safety construction of the heat pipe network project and the supervision in the construction process, so as to lay a theoretical foundation for the smooth progress of the project.
文摘The sustainable development of Chinas social economy, the heating pipe network project has also had a great development. At present, the society gives positive encouragement and advocacy to the sustainable development of the project, and takes energy conservation and emission reduction as a very important task at present. Environmental protection has also become the primary factor of project construction. Central heating has been gradually adopted by construction workers in the heat network, mainly because central heating can greatly reduce the cost of the project. But if there is a problem in a node in the heat network, it will lead to a large area of the heat network without heating phenomenon. Therefore, due to the complex pipe network, the quality danger of heating pipe network is easy to occur in the construction process. Strengthening the construction technology is an important basis to ensure the quality.
