A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretic...A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity.At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5.展开更多
A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were establish...A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.展开更多
A type of hollow cylinder joints connected with H-shaped beams is proposed for spatial structures. Based on von Mises yield criterion and perfect elasto-plasticity model, a series of finite element models of the joint...A type of hollow cylinder joints connected with H-shaped beams is proposed for spatial structures. Based on von Mises yield criterion and perfect elasto-plasticity model, a series of finite element models of the joints is established, in which the effect of geometric nonlinearity is taken into account. Then mechanical behavior and load-carrying capacity of the joints were investigated, which were subjected to axial load, in- and out-plane bending moments, and their combinations. The results show that the ultimate loads of the joints are determined by the maximum displacement. Furthermore, the case of one joint connected with multiple beams was discussed. Experiments on a set of typical full-scale joints were conducted to understand the structural behavior and the failure mechanism of joint, and also to validate the finite element models. Finally, the practical calculation method was established through finite elements analysis (FEA) results and numerical fitting. The results show that the joints are more ductile and materially economical than welded hollow spherical joints, and the practical calculation method can provide a reference for direct design and the revision of relevant design codes.展开更多
Finding out the most effective parameters relating to the resistance of reinforced concrete connections(RCCs)is an important topic in structural engineering.In this study,first,a finite element(FE)model is developed f...Finding out the most effective parameters relating to the resistance of reinforced concrete connections(RCCs)is an important topic in structural engineering.In this study,first,a finite element(FE)model is developed for simulating the performance of RCCs under post-earthquake fire(PEF).Then surrogate models,including multiple linear regression(MLR),multiple natural logarithm(Ln)equation regression(MLn ER),gene expression programming(GEP),and an ensemble model,are used to predict the remaining load-carrying capacity of an RCC under PEF.The statistical parameters,error terms,and a novel statistical table are used to evaluate and compare the accuracy of each surrogate model.According to the results,the ratio of the longitudinal reinforcement bars of the column(RLC)has a significant effect on the resistance of an RCC under PEF.Increasing the value of this parameter from 1%to 8%can increase the residual load-carrying capacity of an RCC under PEF by 492.2%when the RCC is exposed to fire at a temperature of 1000°C.Moreover,based on the results,the ensemble model can predict the residual load-carrying capacity with suitable accuracy.A safety factor of 1.55 should be applied to the results obtained from the ensemble model.展开更多
The elastic-plastic method is often used in designing the inner flat bulkhead plates of submarines, and the upper structure of ships and drilling platforms. Such bulkhead plates can bear the load only once. For the im...The elastic-plastic method is often used in designing the inner flat bulkhead plates of submarines, and the upper structure of ships and drilling platforms. Such bulkhead plates can bear the load only once. For the improvement of the load-carrying capacity or the reduction of the weight of plates, the yield line analytical method is employed in this paper to design the bulkhead plate to improve economy and increase the effiective load. Besides, a further sutdy of this method has been made theoretically and experimentally, and the data of the limited load-carrying capacity of the plate have been obtained. Furthermore, the safety coefficients for such a method are presented, which can be used as reference for related departments and staffs.展开更多
Boundary slippage is used to generate the load-carrying capacity of the hydrodynamic contact between two parallel plane surfaces. In the fluid inlet zone, the fluidcontact interfacial shear strength on a stationary su...Boundary slippage is used to generate the load-carrying capacity of the hydrodynamic contact between two parallel plane surfaces. In the fluid inlet zone, the fluidcontact interfacial shear strength on a stationary surface is set at low to generate boundary slippage there, while in the fluid outlet zone the fluid-contact interfacial shear strength on the stationary surface is set at high enough to prevent the occurrence of boundary slippage. The fluid-contact interfacial shear strength on the entire moving surface is set at high enough to prevent boundary slippage on the moving surface. These hydrodynamic contact configurations are analyzed to generate the pronounced load-carrying capacity. The optimum ratio of the outlet zone width to the inlet zone width for the maximum load-carrying capacity of the whole contact is found to be 0.5.展开更多
The concept of load-carrying capacity of the soil can be evaluated by two main components: permissible stress and permissible depth;and therefore, running it begins its assessment that allows an outline of exploitatio...The concept of load-carrying capacity of the soil can be evaluated by two main components: permissible stress and permissible depth;and therefore, running it begins its assessment that allows an outline of exploitation. Nevertheless, the assessment of the load-carrying capacity made the object of several works of research and many models, based on the multi-criteria analysis, have been established. This work examines the contribution of GIS approach to assessment load-carrying capacity of the soil. This one has been finished in two practicums: 1) Assessment of the capacity of soil by a multi-criteria approach, using the Weighted Sum Model (WSM);2) It brought to use the GIS approach to evaluate and spatialize degree of soil bearing stresses resulting from the buildings, as well as load distribution. The method has been applied to the Berhoum area of Hodna Basin, in eastern Algeria, where each is characterized by its various natural properties and density of equipment. Final results are better in the classification of the degree of load-carrying capacity possible in each site. This results in allowing exploiters to program their optimal designs for the rational management of the area.展开更多
Clearance not only affects the startup torque,rotation precision and stiffness of bearing,but also affects the load distribution,load-carrying capacity and life of bearing.A computational model in which the clearance ...Clearance not only affects the startup torque,rotation precision and stiffness of bearing,but also affects the load distribution,load-carrying capacity and life of bearing.A computational model in which the clearance of bearing is first included is presented for determining the contact force distribution and static load-carrying capacity of a double row four-point contact ball bearing which is subjected to the combined radial,axial and overturning moment loadings.The relation between the negative axial clearance and the contact force distribution is analyzed.The static load-carrying capacity curves are established,and the effects of the changes in negative axial clearance,curvature radius coefficient of raceway groove and initial contact angle on the static load-carrying capacity are analyzed.The results show that,with the increase in the absolute value of negative clearance,the maximum contact load decreases first and then increases.The clearance values in the range of 0.2 mme0 mm have little effect on the static load-carrying capacity of bearing.With the increase in the curvature radius coefficient of raceway groove and the decrease in the initial contact angle,the static load capacity of bearing decreases.展开更多
The aim of this paper is to explore the effect of geometrical parameters on ultimate load-carrying capacity of a circular hollow section(CHS)X-joint under axial compression of the brace end.First of all,finite element...The aim of this paper is to explore the effect of geometrical parameters on ultimate load-carrying capacity of a circular hollow section(CHS)X-joint under axial compression of the brace end.First of all,finite element(FE)model to calculate ultimate load-carrying capacity of the CHS X-joint subjected to uniaxial load of the brace is constructed,and the calculated load–displacement curves are compared to the experimental ones.After validation of the FE model,46080 groups of FE calculation models with different geometrical parameters are generated by means of parametric modeling.Subsequently,eight variables including gusset thickness and chord thickness are set as input to predict load-carrying capacity of the CHS X-joint by four machine learning(ML)algorithms,i.e.,Generalized Regression Neural Network,Support Vector Machine,random forest(RF),and Extreme Gradient Boosting(XGBoost).Finally,the constructed ML prediction models are interpreted by SHapley Additive exPlanations,to explore the impact weight of each factor on ultimate load-carrying capacity of the joint.The results show that all the four models can predict the load-carrying capacity of the subject accurately,with all the R2 values greater than 0.97.In addition,RF model yields the minimum mean-square error,Root Mean Squared Error,Mean Absolute Error,and Mean Absolute Percentage Error values,and the greatest R2 value,while the prediction accuracy of XGBoost is relatively worse.Among all the eight considered geometrical parameters,brace diameter has the strongest impact on load-carrying capacity of the joint,followed by chord thickness,chord ring width,chord ring thickness,brace ring width,and brace thickness,while the thicknesses of the gusset plate and brace have marginal influence on load-carrying capacity.The study of the current paper can provide guidelines for dimension design of CHS X-joints.展开更多
Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longe...Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longer period.A multi-objective genetic algorithm(MOGA)and state of charge(SOC)region division for the batteries are introduced to solve the objective function and configuration of the system capacity,respectively.MATLAB/Simulink was used for simulation test.The optimization results show that for a 0.5 MW wind power and 0.5 MW photovoltaic system,with a combination of a 300 Ah lithium battery,a 200 Ah lead-acid battery,and a water storage tank,the proposed strategy reduces the system construction cost by approximately 18,000 yuan.Additionally,the cycle count of the electrochemical energy storage systemincreases from4515 to 4660,while the depth of discharge decreases from 55.37%to 53.65%,achieving shallow charging and discharging,thereby extending battery life and reducing grid voltage fluctuations significantly.The proposed strategy is a guide for stabilizing the grid connection of wind and solar power generation,capability allocation,and energy management of energy conservation systems.展开更多
Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships w...Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships with antioxidant activity and oxidative stability,gas chromatography-mass spectrometry was performed to characterize the associated fatty acid profiles.The antioxidant activity of vegetable oils,based on their DPPH-scavenging capacity(expressed as IC_(50) values),was used to assess their impact on human health,and their oxidative stability was characterized by performing lipid oxidation analysis to determine the oxidative induction time of fats and oils.In addition,correlation analyses were performed to examine associations between the fatty acid composition of the oils and DPPH-scavenging capacity and oxidative stability.The results revealed that among the assessed oils,coffee seed oil has the highest saturated fatty acid content(355.10 mg/g),whereas Garddenia jaminoides oil has the highest unsaturated fatty acid content(844.84 mg/g).Coffee seed oil was also found have the lowest DPPH IC_(50) value(2.30 mg/mL)and the longest oxidation induction time(17.09 h).Correlation analysis revealed a significant linear relationship(P<0.05)between oxidative stability and unsaturated fatty acid content,with lower contents tending to be associated with better oxidative stability.The findings of this study provide reference data for the screening of functional edible vegetable oils.展开更多
Background Oxidative stress significantly impacts growth performance and liver function in piglets.Ferulic acid(FA)works as an antioxidant,however,the role and mechanism of FA in the regulation of diquat-induced oxida...Background Oxidative stress significantly impacts growth performance and liver function in piglets.Ferulic acid(FA)works as an antioxidant,however,the role and mechanism of FA in the regulation of diquat-induced oxidative stress in piglets are less known.This study was designed to investigate the effects of FA on growth performance and antioxi-dant capacity in piglets with diquat challenge.Methods Thirty-two healthy DLY(Duroc×Landrace×Yorkshire)piglets(13.24±0.19 kg)were randomly divided into one of two diets including 0 or 4 g/kg FA for 14 d.On d 15,all pigs were intraperitoneally injected diquat or sterile saline.Results Dietary supplementation with ferulic acid(FA)significantly improved the average daily gain(ADG)and decreased feed-gain ratio(F/G)of piglets.Here,dietary FA supplementation reduced serum aspartate aminotrans-ferase(AST),alanine aminotransferase(ALT)activities in diquat challenged piglets.Furthermore,diquat infusion increased reactive oxygen radicals(ROS)level in liver,decreased the activities of total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px),total antioxidant capacity(T-AOC)and increased malondialdehyde(MDA)con-tent in the liver and serum.Supplementation with FA significantly increased T-AOC and T-SOD activities and decreased MDA and ROS levels.FA down-regulated gene and protein expression of Keap1,and up-regulated protein expression of Nrf2 and HO-1 in the liver of piglets with diquat challenge.Importantly,diquat challenge increased the ratio of late apoptosis,increased serum levels of IL-1β,IL-18 and lactate dehydrogenase(LDH),and up-regulated pyroptosis-related genes in the liver.FA supplementation reduced the ratio of late apoptosis and down-regulated mRNA expression of Caspase-1.Accordingly,FA addition reduced concentration of IL-1β,IL-18,and LDH under diquat challenge.Conclusions Diquat-induced oxidative stress reduced growth performance and impaired liver function in piglets.Dietary FA supplementation enhanced the antioxidant capacity and reduced the degree of hepatocyte pyroptosis,thereby alleviating the oxidative damage in the liver and mitigating the impact of diquat on growth performance of piglets.展开更多
The increased demand for personalized customization calls for new production modes to enhance collaborations among a wide range of manufacturing practitioners who unnecessarily trust each other.In this article,a block...The increased demand for personalized customization calls for new production modes to enhance collaborations among a wide range of manufacturing practitioners who unnecessarily trust each other.In this article,a blockchain-enabled manufacturing collaboration framework is proposed,with a focus on the production capacity matching problem for blockchainbased peer-to-peer(P2P)collaboration.First,a digital model of production capacity description is built for trustworthy and transparent sharing over the blockchain.Second,an optimization problem is formulated for P2P production capacity matching with objectives to maximize both social welfare and individual benefits of all participants.Third,a feasible solution based on an iterative double auction mechanism is designed to determine the optimal price and quantity for production capacity matching with a lack of personal information.It facilitates automation of the matching process while protecting users'privacy via blockchainbased smart contracts.Finally,simulation results from the Hyperledger Fabric-based prototype show that the proposed approach increases social welfare by 1.4%compared to the Bayesian game-based approach,makes all participants profitable,and achieves 90%fairness of enterprises.展开更多
This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ra...This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.展开更多
In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways Hi...In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.展开更多
Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to...Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.展开更多
To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concret...To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity.展开更多
To exchange experiences and progress in standardization capacity building at home and abroad,the sub-forum on capacity building and creating leadership in standardization was held on July 9.The sub-forum was hosted by...To exchange experiences and progress in standardization capacity building at home and abroad,the sub-forum on capacity building and creating leadership in standardization was held on July 9.The sub-forum was hosted by the Qingdao Municipal People’s Government and co-organized by the International Standardization Training Base(Qingdao),Qingdao University,International Standardization Outstanding Contribution Foundation,and Shandong National Standards Center of Technical Evaluation,which was expected to inject new vitality into the industrial development and provide new ideas for improving the talent cultivation system.展开更多
Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the regularity of this function. We use this funct...Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the regularity of this function. We use this function to provide an accurate characterization of the height of the geodesic defining function for the AH manifold with a given boundary metric. Furthermore, it is shown that such functions are uniformly bounded from below at infinity and the bound only depends on the dimension. In the end, we apply this function to study the capacity of balls in AH manifolds and demonstrate that the “relative p—capacity function” coincides with the relative volume function under appropriate curvature conditions.展开更多
This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The resear...This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The research investigated the impact of surfactant types and concentrations on critical nanoemulsion properties,including droplet size,polydispersity index(PDI),and zeta potential.Using a Box-Behnken Design(BBD)model,the formulation was optimized containing 6.0%plant oils,10.0%Tween 80,2.0%Span 80,and 1.0%lecithin to achieve nano-sized droplets(33.52 nm),with a low PDI(0.205),and a stable zeta potential(15.49 mV).The antioxidant activity,was evaluated through 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging assays,demonstrating its outstanding efficacy.And the optimized nanoemulsion showed a radical-scavenging capacity exceeding 2250μg ascorbic acid equivalents/g,significantly outperforming non-nanoemulsified oils.Stability testing under various environmental conditions highlighted exceptional robustness,with refrigerated samples maintaining structural integrity,minimal particle size growth,and consistent physicochemical properties over a 30-day storage period.The results suggest that the plant oil-based nanoemulsions exhibit strong antioxidant potential,offering a promising natural treatment for their application in cosmeceutical and therapeutic formulations.展开更多
基金co-supported by the National Natural Science Foundation of China (No. 51505338 and No. 51475332)the Youths Science Foundation of Zhejiang (No. LQ16E050004 and No. LQ17E050003)
文摘A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity.At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5.
基金Project(51178333)supported by the National Natural Science Foundation of ChinaProject(SLDRCE09-D-03)supported by the Ministry of Science and Technology of China
文摘A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.
基金Project supported by the National Natural Science Foundation of China (No. 51178414)the Science Foundation of Zhejiang Province (No. Y1110438), China
文摘A type of hollow cylinder joints connected with H-shaped beams is proposed for spatial structures. Based on von Mises yield criterion and perfect elasto-plasticity model, a series of finite element models of the joints is established, in which the effect of geometric nonlinearity is taken into account. Then mechanical behavior and load-carrying capacity of the joints were investigated, which were subjected to axial load, in- and out-plane bending moments, and their combinations. The results show that the ultimate loads of the joints are determined by the maximum displacement. Furthermore, the case of one joint connected with multiple beams was discussed. Experiments on a set of typical full-scale joints were conducted to understand the structural behavior and the failure mechanism of joint, and also to validate the finite element models. Finally, the practical calculation method was established through finite elements analysis (FEA) results and numerical fitting. The results show that the joints are more ductile and materially economical than welded hollow spherical joints, and the practical calculation method can provide a reference for direct design and the revision of relevant design codes.
文摘Finding out the most effective parameters relating to the resistance of reinforced concrete connections(RCCs)is an important topic in structural engineering.In this study,first,a finite element(FE)model is developed for simulating the performance of RCCs under post-earthquake fire(PEF).Then surrogate models,including multiple linear regression(MLR),multiple natural logarithm(Ln)equation regression(MLn ER),gene expression programming(GEP),and an ensemble model,are used to predict the remaining load-carrying capacity of an RCC under PEF.The statistical parameters,error terms,and a novel statistical table are used to evaluate and compare the accuracy of each surrogate model.According to the results,the ratio of the longitudinal reinforcement bars of the column(RLC)has a significant effect on the resistance of an RCC under PEF.Increasing the value of this parameter from 1%to 8%can increase the residual load-carrying capacity of an RCC under PEF by 492.2%when the RCC is exposed to fire at a temperature of 1000°C.Moreover,based on the results,the ensemble model can predict the residual load-carrying capacity with suitable accuracy.A safety factor of 1.55 should be applied to the results obtained from the ensemble model.
文摘The elastic-plastic method is often used in designing the inner flat bulkhead plates of submarines, and the upper structure of ships and drilling platforms. Such bulkhead plates can bear the load only once. For the improvement of the load-carrying capacity or the reduction of the weight of plates, the yield line analytical method is employed in this paper to design the bulkhead plate to improve economy and increase the effiective load. Besides, a further sutdy of this method has been made theoretically and experimentally, and the data of the limited load-carrying capacity of the plate have been obtained. Furthermore, the safety coefficients for such a method are presented, which can be used as reference for related departments and staffs.
文摘Boundary slippage is used to generate the load-carrying capacity of the hydrodynamic contact between two parallel plane surfaces. In the fluid inlet zone, the fluidcontact interfacial shear strength on a stationary surface is set at low to generate boundary slippage there, while in the fluid outlet zone the fluid-contact interfacial shear strength on the stationary surface is set at high enough to prevent the occurrence of boundary slippage. The fluid-contact interfacial shear strength on the entire moving surface is set at high enough to prevent boundary slippage on the moving surface. These hydrodynamic contact configurations are analyzed to generate the pronounced load-carrying capacity. The optimum ratio of the outlet zone width to the inlet zone width for the maximum load-carrying capacity of the whole contact is found to be 0.5.
文摘The concept of load-carrying capacity of the soil can be evaluated by two main components: permissible stress and permissible depth;and therefore, running it begins its assessment that allows an outline of exploitation. Nevertheless, the assessment of the load-carrying capacity made the object of several works of research and many models, based on the multi-criteria analysis, have been established. This work examines the contribution of GIS approach to assessment load-carrying capacity of the soil. This one has been finished in two practicums: 1) Assessment of the capacity of soil by a multi-criteria approach, using the Weighted Sum Model (WSM);2) It brought to use the GIS approach to evaluate and spatialize degree of soil bearing stresses resulting from the buildings, as well as load distribution. The method has been applied to the Berhoum area of Hodna Basin, in eastern Algeria, where each is characterized by its various natural properties and density of equipment. Final results are better in the classification of the degree of load-carrying capacity possible in each site. This results in allowing exploiters to program their optimal designs for the rational management of the area.
基金supported by NSFC(51105131)Excellent Youth Foundation of Henan Scientific Committee(124100510002)Creative Talent Foundation in University of Henan Province(2011HASTIT016)
文摘Clearance not only affects the startup torque,rotation precision and stiffness of bearing,but also affects the load distribution,load-carrying capacity and life of bearing.A computational model in which the clearance of bearing is first included is presented for determining the contact force distribution and static load-carrying capacity of a double row four-point contact ball bearing which is subjected to the combined radial,axial and overturning moment loadings.The relation between the negative axial clearance and the contact force distribution is analyzed.The static load-carrying capacity curves are established,and the effects of the changes in negative axial clearance,curvature radius coefficient of raceway groove and initial contact angle on the static load-carrying capacity are analyzed.The results show that,with the increase in the absolute value of negative clearance,the maximum contact load decreases first and then increases.The clearance values in the range of 0.2 mme0 mm have little effect on the static load-carrying capacity of bearing.With the increase in the curvature radius coefficient of raceway groove and the decrease in the initial contact angle,the static load capacity of bearing decreases.
文摘The aim of this paper is to explore the effect of geometrical parameters on ultimate load-carrying capacity of a circular hollow section(CHS)X-joint under axial compression of the brace end.First of all,finite element(FE)model to calculate ultimate load-carrying capacity of the CHS X-joint subjected to uniaxial load of the brace is constructed,and the calculated load–displacement curves are compared to the experimental ones.After validation of the FE model,46080 groups of FE calculation models with different geometrical parameters are generated by means of parametric modeling.Subsequently,eight variables including gusset thickness and chord thickness are set as input to predict load-carrying capacity of the CHS X-joint by four machine learning(ML)algorithms,i.e.,Generalized Regression Neural Network,Support Vector Machine,random forest(RF),and Extreme Gradient Boosting(XGBoost).Finally,the constructed ML prediction models are interpreted by SHapley Additive exPlanations,to explore the impact weight of each factor on ultimate load-carrying capacity of the joint.The results show that all the four models can predict the load-carrying capacity of the subject accurately,with all the R2 values greater than 0.97.In addition,RF model yields the minimum mean-square error,Root Mean Squared Error,Mean Absolute Error,and Mean Absolute Percentage Error values,and the greatest R2 value,while the prediction accuracy of XGBoost is relatively worse.Among all the eight considered geometrical parameters,brace diameter has the strongest impact on load-carrying capacity of the joint,followed by chord thickness,chord ring width,chord ring thickness,brace ring width,and brace thickness,while the thicknesses of the gusset plate and brace have marginal influence on load-carrying capacity.The study of the current paper can provide guidelines for dimension design of CHS X-joints.
基金supported by a Horizontal Project on the Development of a Hybrid Energy Storage Simulation Model for Wind Power Based on an RT-LAB Simulation System(PH2023000190)the Inner Mongolia Natural Science Foundation Project and the Optimization of Exergy Efficiency of a Hybrid Energy Storage System with Crossover Control for Wind Power(2023JQ04).
文摘Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longer period.A multi-objective genetic algorithm(MOGA)and state of charge(SOC)region division for the batteries are introduced to solve the objective function and configuration of the system capacity,respectively.MATLAB/Simulink was used for simulation test.The optimization results show that for a 0.5 MW wind power and 0.5 MW photovoltaic system,with a combination of a 300 Ah lithium battery,a 200 Ah lead-acid battery,and a water storage tank,the proposed strategy reduces the system construction cost by approximately 18,000 yuan.Additionally,the cycle count of the electrochemical energy storage systemincreases from4515 to 4660,while the depth of discharge decreases from 55.37%to 53.65%,achieving shallow charging and discharging,thereby extending battery life and reducing grid voltage fluctuations significantly.The proposed strategy is a guide for stabilizing the grid connection of wind and solar power generation,capability allocation,and energy management of energy conservation systems.
文摘Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships with antioxidant activity and oxidative stability,gas chromatography-mass spectrometry was performed to characterize the associated fatty acid profiles.The antioxidant activity of vegetable oils,based on their DPPH-scavenging capacity(expressed as IC_(50) values),was used to assess their impact on human health,and their oxidative stability was characterized by performing lipid oxidation analysis to determine the oxidative induction time of fats and oils.In addition,correlation analyses were performed to examine associations between the fatty acid composition of the oils and DPPH-scavenging capacity and oxidative stability.The results revealed that among the assessed oils,coffee seed oil has the highest saturated fatty acid content(355.10 mg/g),whereas Garddenia jaminoides oil has the highest unsaturated fatty acid content(844.84 mg/g).Coffee seed oil was also found have the lowest DPPH IC_(50) value(2.30 mg/mL)and the longest oxidation induction time(17.09 h).Correlation analysis revealed a significant linear relationship(P<0.05)between oxidative stability and unsaturated fatty acid content,with lower contents tending to be associated with better oxidative stability.The findings of this study provide reference data for the screening of functional edible vegetable oils.
基金Sichuan Science and Technology Program(No.2021ZDZX0009).
文摘Background Oxidative stress significantly impacts growth performance and liver function in piglets.Ferulic acid(FA)works as an antioxidant,however,the role and mechanism of FA in the regulation of diquat-induced oxidative stress in piglets are less known.This study was designed to investigate the effects of FA on growth performance and antioxi-dant capacity in piglets with diquat challenge.Methods Thirty-two healthy DLY(Duroc×Landrace×Yorkshire)piglets(13.24±0.19 kg)were randomly divided into one of two diets including 0 or 4 g/kg FA for 14 d.On d 15,all pigs were intraperitoneally injected diquat or sterile saline.Results Dietary supplementation with ferulic acid(FA)significantly improved the average daily gain(ADG)and decreased feed-gain ratio(F/G)of piglets.Here,dietary FA supplementation reduced serum aspartate aminotrans-ferase(AST),alanine aminotransferase(ALT)activities in diquat challenged piglets.Furthermore,diquat infusion increased reactive oxygen radicals(ROS)level in liver,decreased the activities of total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px),total antioxidant capacity(T-AOC)and increased malondialdehyde(MDA)con-tent in the liver and serum.Supplementation with FA significantly increased T-AOC and T-SOD activities and decreased MDA and ROS levels.FA down-regulated gene and protein expression of Keap1,and up-regulated protein expression of Nrf2 and HO-1 in the liver of piglets with diquat challenge.Importantly,diquat challenge increased the ratio of late apoptosis,increased serum levels of IL-1β,IL-18 and lactate dehydrogenase(LDH),and up-regulated pyroptosis-related genes in the liver.FA supplementation reduced the ratio of late apoptosis and down-regulated mRNA expression of Caspase-1.Accordingly,FA addition reduced concentration of IL-1β,IL-18,and LDH under diquat challenge.Conclusions Diquat-induced oxidative stress reduced growth performance and impaired liver function in piglets.Dietary FA supplementation enhanced the antioxidant capacity and reduced the degree of hepatocyte pyroptosis,thereby alleviating the oxidative damage in the liver and mitigating the impact of diquat on growth performance of piglets.
基金supported in part by the National Natural Science Foundation of China(62273310)the Natural Science Foundation of Zhejiang Province of China(LY22F030006,LZ24F030009)
文摘The increased demand for personalized customization calls for new production modes to enhance collaborations among a wide range of manufacturing practitioners who unnecessarily trust each other.In this article,a blockchain-enabled manufacturing collaboration framework is proposed,with a focus on the production capacity matching problem for blockchainbased peer-to-peer(P2P)collaboration.First,a digital model of production capacity description is built for trustworthy and transparent sharing over the blockchain.Second,an optimization problem is formulated for P2P production capacity matching with objectives to maximize both social welfare and individual benefits of all participants.Third,a feasible solution based on an iterative double auction mechanism is designed to determine the optimal price and quantity for production capacity matching with a lack of personal information.It facilitates automation of the matching process while protecting users'privacy via blockchainbased smart contracts.Finally,simulation results from the Hyperledger Fabric-based prototype show that the proposed approach increases social welfare by 1.4%compared to the Bayesian game-based approach,makes all participants profitable,and achieves 90%fairness of enterprises.
基金supported by grants from the Natural Science Foundation of Fujian Province(2021J011062)Minjiang Scholars Funding(GY-633Z21067).
文摘This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.
基金funded by the National Natural Science Foundation of China(52167013)the Key Program of Natural Science Foundation of Gansu Province(24JRRA225)Natural Science Foundation of Gansu Province(23JRRA891).
文摘In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.
文摘Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.
文摘To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity.
文摘To exchange experiences and progress in standardization capacity building at home and abroad,the sub-forum on capacity building and creating leadership in standardization was held on July 9.The sub-forum was hosted by the Qingdao Municipal People’s Government and co-organized by the International Standardization Training Base(Qingdao),Qingdao University,International Standardization Outstanding Contribution Foundation,and Shandong National Standards Center of Technical Evaluation,which was expected to inject new vitality into the industrial development and provide new ideas for improving the talent cultivation system.
文摘Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the regularity of this function. We use this function to provide an accurate characterization of the height of the geodesic defining function for the AH manifold with a given boundary metric. Furthermore, it is shown that such functions are uniformly bounded from below at infinity and the bound only depends on the dimension. In the end, we apply this function to study the capacity of balls in AH manifolds and demonstrate that the “relative p—capacity function” coincides with the relative volume function under appropriate curvature conditions.
基金Ho Chi Minh City University of Technology(HCMUT),VNU-HCM,for supporting this study.
文摘This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The research investigated the impact of surfactant types and concentrations on critical nanoemulsion properties,including droplet size,polydispersity index(PDI),and zeta potential.Using a Box-Behnken Design(BBD)model,the formulation was optimized containing 6.0%plant oils,10.0%Tween 80,2.0%Span 80,and 1.0%lecithin to achieve nano-sized droplets(33.52 nm),with a low PDI(0.205),and a stable zeta potential(15.49 mV).The antioxidant activity,was evaluated through 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging assays,demonstrating its outstanding efficacy.And the optimized nanoemulsion showed a radical-scavenging capacity exceeding 2250μg ascorbic acid equivalents/g,significantly outperforming non-nanoemulsified oils.Stability testing under various environmental conditions highlighted exceptional robustness,with refrigerated samples maintaining structural integrity,minimal particle size growth,and consistent physicochemical properties over a 30-day storage period.The results suggest that the plant oil-based nanoemulsions exhibit strong antioxidant potential,offering a promising natural treatment for their application in cosmeceutical and therapeutic formulations.
