Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the inte...Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.展开更多
The present paper analyses a case study of the application of dynamic energy simulation on the energy efficiency improvement process of an existing commercial building,the retrofit of a CHP machine for the combined ge...The present paper analyses a case study of the application of dynamic energy simulation on the energy efficiency improvement process of an existing commercial building,the retrofit of a CHP machine for the combined generation of heat and power is analysed.Great attention is dedicated to the correct sizing of the CHP/CCHP plant both in term of energy efficiency and economic viability.A detailed building model is developed and used,through dynamic building simulation,to identify the potential energy and economic savings achievable with the installation of a CHP/CCHP sized based on the results of the simulation itself.The work proves the usefulness of dynamic energy simulation as an evaluation tool for retrofits of CHP plants and provides suggestions on the correct sizing of CHP equipment.It is also meant to prove what could be achieved if those kinds of analysis were carried out during the design of the building.展开更多
The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behav...The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behavior.Classical continuum theories are inadequate at micro-and nanoscales,particularly concerning size effects,singularities,and phenomena like strain softening or phase transitions.This limitation follows from their lack of intrinsic length scale parameters,crucial for representingmicrostructural features.Theoretical and experimental findings emphasize the critical role of these parameters on small scales.This review thoroughly examines various strain gradient elasticity(SGE)theories commonly employed in literature to capture these size-dependent effects on the elastic response.Given the complexity arising from numerous SGE frameworks available in the literature,including first-and second-order gradient theories,we conduct a comprehensive and comparative analysis of common SGE models.This analysis highlights their unique physical interpretations and compares their effectiveness in modeling the size-dependent behavior of low-dimensional structures.A brief discussion on estimating additional material constants,such as intrinsic length scales,is also included to improve the practical relevance of SGE.Following this theoretical treatment,the review covers analytical and numerical methods for solving the associated higher-order governing differential equations.Finally,we present a detailed overview of strain gradient applications in multiscale andmultiphysics response of solids.Interesting research on exploring the relevance of SGE for reduced-order modeling of complex macrostructures,a universal multiphysics coupling in low-dimensional structures without being restricted to limited material symmetries(as in the case of microstructures),is also presented here for interested readers.Finally,we briefly discuss alternative nonlocal elasticity approaches(integral and integro-differential)for incorporating size effects,and conclude with some potential areas for future research on strain gradients.This review aims to provide a clear understanding of strain gradient theories and their broad applicability beyond classical elasticity.展开更多
Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method bas...Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method based on the Mask-RCNN framework. A dataset of 9880 high-resolution images was captured by using a self-made fiber-optic endoscopic system for 13 kinds of silicoaluminophosphate-34 (SAPO-34) catalyst samples with different coke. Then there were approximately 877881 individual particles extracted from this dataset by our AI-based particle recognition algorithm. To clearly describe the morphology of irregular particles, we proposed a hybrid classification criterion that combines five different parameters, which are deformity, circularity, roundness, aspect ratio, and compactness. Therefore, catalyst morphology can be classified into two categories with four types. The first category includes regular types, such as the spherical, ellipsoidal, and rod-shaped types. And all the irregular types fall into the second category. The experimental results showed that a catalyst particle tends to be larger when its coke deposition increased. Whereas particle morphology remained primarily spherical and ellipsoidal, the ratio of each type varied slightly according to its coke. Our findings illustrate that this is a promising approach to be developing intelligent instruments for catalyst particle sizing and classification.展开更多
An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitabl...An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitable for these integrated shape/sizing optimization is obtained. The uniform design method is used to provide sample points, and approximation models for shape design variables. And the results of sizing optimization are construct- ed with the quadratic response surface method （QRSM）. The complex method based on QRSM is used to opti- mize the shape design variables and the criteria method is adopted to optimize the sizing design variables. Compared with the conventional method, the proposed algorithm is more effective and feasible for solving complex composite optimization problems and has good efficiency in weight cutting.展开更多
Based on the concept of the converter fed machines (CFMs), an optimal machine design can be considered as the best match of the machine topology, the power electronic converter and the performance specifications. To e...Based on the concept of the converter fed machines (CFMs), an optimal machine design can be considered as the best match of the machine topology, the power electronic converter and the performance specifications. To evaluate power production potentials of machines with various topologies with different waveforms of back emf and current, the generalized sizing equations and the power density equation are needed to evaluate the main dimensions and the power of such machines. In this paper. a general approach is presented to develop and to discuss these equations. Sample applications of the generalized sizing and power density equations are utilized to evaluate the induction machine and the double-salient permanent magnet (DSPM) machine.展开更多
Porous ZnO films are synthesized by inorganic chelating sol-gel method,which is a novel sol-gel technique using zinc nitrate as starting materials and citric acid as the chelating reagent.The crystal structure,surface...Porous ZnO films are synthesized by inorganic chelating sol-gel method,which is a novel sol-gel technique using zinc nitrate as starting materials and citric acid as the chelating reagent.The crystal structure,surface morphology,porous and optical properties of the deposited films are investigated.X-ray diffraction pattern analysis shows that crystal structure of the ZnO films is hexagonal wurtzite.Scanning electron microscopy (SEM) shows that the ZnO film is porous.The curve of pore size distribution has two peak values at about 2.02nm and 4.97nm and BET surface area of the ZnO film is 27.57m2/g.In addition,the transmittance spectrum gives a high transmittance of 85% in the visible region and optical bandgap of the ZnO film (fired at 500℃) is 3.25eV.展开更多
The nonlinear biased ship rolling motion and capsizing in randoro waves are studied by utilizing a global geometric method. Thompson＇ s α-parameterized family of restoring functions is adopted in the vessel equation...The nonlinear biased ship rolling motion and capsizing in randoro waves are studied by utilizing a global geometric method. Thompson＇ s α-parameterized family of restoring functions is adopted in the vessel equation of motion for the representation of bias. To take into account the presence of randomness in the excitation and the response, a stochastic Melnikov method is developed and a mean-square criterion is obtained to provide an upper bound on the domain of the potential chaotic rolling motion. This criterion can be used to predict the qualitative nature of the invariant manifolds which represent the boundary botween safe and unsafe initial conditions, and how these depend on system parameters of the specific ship model. Phase space transport theory and lobe dynamics are used to demonstrate how motions starting from initial conditions inside the regions bounded by the intersected manifolds will evolve and how unexpected capsizing can occur.展开更多
One of the most important characters of blasting,a basic step of surface mining,is rock fragmentation because it directly effects on the costs of drilling and economics of the subsequent operations of loading,hauling ...One of the most important characters of blasting,a basic step of surface mining,is rock fragmentation because it directly effects on the costs of drilling and economics of the subsequent operations of loading,hauling and crushing in mines.Adaptive neuro-fuzzy inference system(ANFIS)and radial basis function(RBF)show potentials for modeling the behavior of complex nonlinear processes such as those involved in fragmentation due to blasting of rocks.We developed ANFIS and RBF methods for modeling of sizing of rock fragmentation due to bench blasting by estimation of 80%passing size(K_(80))of Golgohar iron mine of Sirjan.Iran.Comparing the results of ANFIS and RBF models shows that although the statistical parameters RBF model is acceptable but ANFIS proposed model is superior and also simpler because ANFIS model is constructed using only two input parameters while seven input parameters used for construction of RBF model.展开更多
The single fiber fragmentation test （SFFT） was used to measure the interracial shear strength （IFSS） of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respecti...The single fiber fragmentation test （SFFT） was used to measure the interracial shear strength （IFSS） of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.展开更多
Grafting a number of monomers such as acrylic acid, acrylamide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate and vinyl acetate onto granular corn starch was carried out resp...Grafting a number of monomers such as acrylic acid, acrylamide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate and vinyl acetate onto granular corn starch was carried out respectively in aqueous dispersion by using cerie ammonium nitrate as an initiator under nitrogen atmosphere. Conversion of monomer, grafting ratio and grafting efficiency were measured by the method of combining the chemical quantitative analysis with the weight. The adhesive power of the starch graft copolymers to polyester/cotton fiber was evaluated by measuring the breaking strength and elongation of the roving impregnated with the paste. The viscosity change of the size paste before and after grafting was studied. The mechanical properties of polyester/cotton fibre yarn sized by the graft starch were tested. The main conclusions are as follows: (1) monomers which were graft coplymerized onto starch have a significant influence upon the viscosity of the size paste; (2) the adhesive power展开更多
The capacitated lot sizing and scheduling problem that involves indetermining the production amounts and release dates for several items over a given planning horizonare given to meet dynamic order demand without incu...The capacitated lot sizing and scheduling problem that involves indetermining the production amounts and release dates for several items over a given planning horizonare given to meet dynamic order demand without incurring backloggings. The problem consideringovertime capacity is studied. The mathematical model is presented, and a genetic algorithm (GA)approach is developed to solve the problem. The initial solutions are generated after usingheuristic method. Capacity balancing procedure is employed to stipulate the feasibility of thesolutions. In addition, a technique based on Tabu search (TS) is inserted into the genetic algorithmdeal with the scheduled overtime and help the convergence of algorithm. Computational simulation isconducted to test the efficiency of the proposed hybrid approach, which turns out to improve boththe solution quality and execution speed.展开更多
A series of dodecenylsuccinylated starches( DSSs) with different degree of substitution( DS) were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for in...A series of dodecenylsuccinylated starches( DSSs) with different degree of substitution( DS) were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for investigating the influences of starch dodecenylsuccinylation upon the performances such as apparent viscosity and surface tension of starch paste, film behaviors,and adhesion to fibers for warp sizing. It was found that the dodecenylsuccinylation was able to reduce the surface tension of cooked starch paste and enhance the adhesion of starch to polyester fibers. It was also capable of depressing the brittleness of native starch and improving the mechanical behaviours such as breaking elongation and work-to-break of starch film. Initial increase in DS level of dodecenylsuccinylation enhanced these positive effects,while excessively increasing the level resulted in marked reduction in tensile strength of starch film and significant decrement in reaction efficiency. X-ray diffraction patterns of starch films showed the dodecenylsuccinates derivatized onto the backbones of starch depressed the degree of crystallinity of starch film. Based on the paste behaviors, adhesion, and film properties, the dodecenylsuccinylation level is recommended in a range of 0. 015-0. 025 for sizing polyester warps.展开更多
Studies show that supply chain cooperation improves supply chain performance. However, it remains a challenge to develop and implement the realistic supply chain cooperation scheme. We investigate a two-echelon supply...Studies show that supply chain cooperation improves supply chain performance. However, it remains a challenge to develop and implement the realistic supply chain cooperation scheme. We investigate a two-echelon supply chain planning problem with capacity acquisition decision under asymmetric cost and demand information. A simple negotiation-based coordination mechanism is developed to synchronize production/order strategies of a supplier and a buyer. The coordination scheme shows how the supplier and the buyer modify their production and order policy in order to find a joint economic lot sizing plan, which saves the overall supply chain cost. The allocation of the cooperation benefit is determined by negotiation. Due to the complexity of the multiple periods, multiple level supply chain lot sizing with capacity decision, a heuristic algorithm is developed to find coordination solutions. Finally, the results of the numerical study indicate the performance of supply chain coordination scheme.展开更多
The hollow parts formed with cross-wedge rolling (CWR) have a wide application in many fields, such as architecture and automobile, etc. But the finished configuration of part’s cross section was always ellipse and i...The hollow parts formed with cross-wedge rolling (CWR) have a wide application in many fields, such as architecture and automobile, etc. But the finished configuration of part’s cross section was always ellipse and it was hard to make it satisfied with traditional forming process. This paper proposed a FEM model of hollow workpiece of CWR in the sizing process, and simulated the deformation condition using the ANSYS program. Three kinds of parts with different wall thickness were calculated. Some stress and strain fields of the deformed hollow parts at various conditions are gained. The influence of wall thickness on the distribution of stress and strain was analyzed. The paper also found two phenomena, which never have been seen at traditional experiment, and author tried to give some explanations. The ANSYS program provided the relationship between the tolerance of the deformed workpiece and the deforming parameter. It is helpful to design the sizing dies of a new precise forming process of hollow parts on the CWR. The new process that designed through the information of FEM improved the accuracy of hollow parts on CWR. It proved the validity and practicability of numerical simulation.展开更多
A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composi...A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition upon the performance such as apparent viscosity,film behaviors,and adhesion capacity to fibers for warp sizing operation.The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method,the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength,breaking elongation,solution time and hygroscopic capacity.It was found that the viscosity,adhesion capability,glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio.Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance.A favorable mole ratio of vinyl acetate or acrylamide was found to be 45∶55.Based on this mole ratio,the adhesion capability and film behaviors of the sizing agent reach their maximal values simultaneously.This demonstrates that the sizing agent should be synthesized under this copolymer composition from the viewpoint of adhesion and film behaviors.展开更多
Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy (XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unit...Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy (XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retain more rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine (PAAm) and polyvinylamine (PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate (PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.展开更多
Sizing treatment has shown great potential in improving the interfacial properties of poly(p-phenylene benzodioxazole)(PBO)fiber-reinforced composites,but is severely limited due to the use of flammable and explosive ...Sizing treatment has shown great potential in improving the interfacial properties of poly(p-phenylene benzodioxazole)(PBO)fiber-reinforced composites,but is severely limited due to the use of flammable and explosive organic solvents.Herein,a new high-efficiency waterborne sizing agent has been developed by using functionalized carbon nanospheres(CNSs)as a nano-reinforcement.Due to abundant oxygen-containing groups,the CNSs greatly improves the surface activity,wettability,and roughness of the PBO fibers.As a result,the interfacial shear strength of the CNSs sized fiber-reinforced composite increases by 79.6%compared with that of the pristine fiber-reinforced composite.Moreover,the excellent mechanical and thermal properties of the PBO fibers remain almost unchanged after sizing treatment.Thus,this work provides an environmentally friendly and scalable method for constructing a strong interface between the PBO fibers and the matrix resins,which makes sense in promoting the application of PBO fiber-reinforced composites in aerospace and military industries.展开更多
Renewable energy sources(RESs)are considered to be reliable and green electric power generation sources.Photovoltaics(PVs)and wind turbines(WTs)are used to provide electricity in remote areas.Optimal sizing of hybrid ...Renewable energy sources(RESs)are considered to be reliable and green electric power generation sources.Photovoltaics(PVs)and wind turbines(WTs)are used to provide electricity in remote areas.Optimal sizing of hybrid RESs is a vital challenge in a stand-alone environment.The meta-heuristic algorithms proposed in the past are dependent on algorithm-specific parameters for achieving an optimal solution.This paper proposes a hybrid algorithm of Jaya and a teaching–learning-based optimization(TLBO)named the JLBO algorithm for the optimal unit sizing of a PV–WT–battery hybrid system to satisfy the consumer’s load at minimal total annual cost(TAC).The reliability of the system is considered by a maximum allowable loss of power supply probability(LPSPmax)concept.The results obtained from the JLBO algorithm are compared with the original Jaya,TLBO,and genetic algorithms.The JLBO results show superior performance in terms of TAC,and the PV–WT–battery hybrid system is found to be the most economical scenario.This system provides a cost-effective solution for all proposed LPSPmax values as compared with PV–battery and WT–battery systems.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U22A20252 and 52173076)the Beijing Natural Science Foundation(Nos.Z240030 and L248023)the Liaoning Province Key Research and Development Project(No.2024JH2/102400046)。
文摘Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.
文摘The present paper analyses a case study of the application of dynamic energy simulation on the energy efficiency improvement process of an existing commercial building,the retrofit of a CHP machine for the combined generation of heat and power is analysed.Great attention is dedicated to the correct sizing of the CHP/CCHP plant both in term of energy efficiency and economic viability.A detailed building model is developed and used,through dynamic building simulation,to identify the potential energy and economic savings achievable with the installation of a CHP/CCHP sized based on the results of the simulation itself.The work proves the usefulness of dynamic energy simulation as an evaluation tool for retrofits of CHP plants and provides suggestions on the correct sizing of CHP equipment.It is also meant to prove what could be achieved if those kinds of analysis were carried out during the design of the building.
基金support from the Anusandhan National Research Foundation(ANRF),erstwhile Science and Engineering Research Board(SERB),India,under the startup research grant program(SRG/2022/000566).
文摘The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behavior.Classical continuum theories are inadequate at micro-and nanoscales,particularly concerning size effects,singularities,and phenomena like strain softening or phase transitions.This limitation follows from their lack of intrinsic length scale parameters,crucial for representingmicrostructural features.Theoretical and experimental findings emphasize the critical role of these parameters on small scales.This review thoroughly examines various strain gradient elasticity(SGE)theories commonly employed in literature to capture these size-dependent effects on the elastic response.Given the complexity arising from numerous SGE frameworks available in the literature,including first-and second-order gradient theories,we conduct a comprehensive and comparative analysis of common SGE models.This analysis highlights their unique physical interpretations and compares their effectiveness in modeling the size-dependent behavior of low-dimensional structures.A brief discussion on estimating additional material constants,such as intrinsic length scales,is also included to improve the practical relevance of SGE.Following this theoretical treatment,the review covers analytical and numerical methods for solving the associated higher-order governing differential equations.Finally,we present a detailed overview of strain gradient applications in multiscale andmultiphysics response of solids.Interesting research on exploring the relevance of SGE for reduced-order modeling of complex macrostructures,a universal multiphysics coupling in low-dimensional structures without being restricted to limited material symmetries(as in the case of microstructures),is also presented here for interested readers.Finally,we briefly discuss alternative nonlocal elasticity approaches(integral and integro-differential)for incorporating size effects,and conclude with some potential areas for future research on strain gradients.This review aims to provide a clear understanding of strain gradient theories and their broad applicability beyond classical elasticity.
基金supported by the National Natural Science Foundation of China(22308348)the Natural Science Foundation of Liaoning Province of China(2024-MSBA-65)+1 种基金the Qin Chuangyuan Project for Introducing High-Level Innovative and Entrepreneurial Talents(QCYRCXM-2023-024)the Energy Revolution S&T Program of Yulin Innovation Institute of Clean Energy(E201041206).
文摘Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method based on the Mask-RCNN framework. A dataset of 9880 high-resolution images was captured by using a self-made fiber-optic endoscopic system for 13 kinds of silicoaluminophosphate-34 (SAPO-34) catalyst samples with different coke. Then there were approximately 877881 individual particles extracted from this dataset by our AI-based particle recognition algorithm. To clearly describe the morphology of irregular particles, we proposed a hybrid classification criterion that combines five different parameters, which are deformity, circularity, roundness, aspect ratio, and compactness. Therefore, catalyst morphology can be classified into two categories with four types. The first category includes regular types, such as the spherical, ellipsoidal, and rod-shaped types. And all the irregular types fall into the second category. The experimental results showed that a catalyst particle tends to be larger when its coke deposition increased. Whereas particle morphology remained primarily spherical and ellipsoidal, the ratio of each type varied slightly according to its coke. Our findings illustrate that this is a promising approach to be developing intelligent instruments for catalyst particle sizing and classification.
文摘An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitable for these integrated shape/sizing optimization is obtained. The uniform design method is used to provide sample points, and approximation models for shape design variables. And the results of sizing optimization are construct- ed with the quadratic response surface method （QRSM）. The complex method based on QRSM is used to opti- mize the shape design variables and the criteria method is adopted to optimize the sizing design variables. Compared with the conventional method, the proposed algorithm is more effective and feasible for solving complex composite optimization problems and has good efficiency in weight cutting.
文摘Based on the concept of the converter fed machines (CFMs), an optimal machine design can be considered as the best match of the machine topology, the power electronic converter and the performance specifications. To evaluate power production potentials of machines with various topologies with different waveforms of back emf and current, the generalized sizing equations and the power density equation are needed to evaluate the main dimensions and the power of such machines. In this paper. a general approach is presented to develop and to discuss these equations. Sample applications of the generalized sizing and power density equations are utilized to evaluate the induction machine and the double-salient permanent magnet (DSPM) machine.
文摘Porous ZnO films are synthesized by inorganic chelating sol-gel method,which is a novel sol-gel technique using zinc nitrate as starting materials and citric acid as the chelating reagent.The crystal structure,surface morphology,porous and optical properties of the deposited films are investigated.X-ray diffraction pattern analysis shows that crystal structure of the ZnO films is hexagonal wurtzite.Scanning electron microscopy (SEM) shows that the ZnO film is porous.The curve of pore size distribution has two peak values at about 2.02nm and 4.97nm and BET surface area of the ZnO film is 27.57m2/g.In addition,the transmittance spectrum gives a high transmittance of 85% in the visible region and optical bandgap of the ZnO film (fired at 500℃) is 3.25eV.
文摘The nonlinear biased ship rolling motion and capsizing in randoro waves are studied by utilizing a global geometric method. Thompson＇ s α-parameterized family of restoring functions is adopted in the vessel equation of motion for the representation of bias. To take into account the presence of randomness in the excitation and the response, a stochastic Melnikov method is developed and a mean-square criterion is obtained to provide an upper bound on the domain of the potential chaotic rolling motion. This criterion can be used to predict the qualitative nature of the invariant manifolds which represent the boundary botween safe and unsafe initial conditions, and how these depend on system parameters of the specific ship model. Phase space transport theory and lobe dynamics are used to demonstrate how motions starting from initial conditions inside the regions bounded by the intersected manifolds will evolve and how unexpected capsizing can occur.
基金financially supported by the Special Fund of Islamic Azad University,Malayer Branch(No.2293)
文摘One of the most important characters of blasting,a basic step of surface mining,is rock fragmentation because it directly effects on the costs of drilling and economics of the subsequent operations of loading,hauling and crushing in mines.Adaptive neuro-fuzzy inference system(ANFIS)and radial basis function(RBF)show potentials for modeling the behavior of complex nonlinear processes such as those involved in fragmentation due to blasting of rocks.We developed ANFIS and RBF methods for modeling of sizing of rock fragmentation due to bench blasting by estimation of 80%passing size(K_(80))of Golgohar iron mine of Sirjan.Iran.Comparing the results of ANFIS and RBF models shows that although the statistical parameters RBF model is acceptable but ANFIS proposed model is superior and also simpler because ANFIS model is constructed using only two input parameters while seven input parameters used for construction of RBF model.
文摘The single fiber fragmentation test （SFFT） was used to measure the interracial shear strength （IFSS） of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.
基金This paper was financially supported by the doctoral foundation of Colleges and Universities
文摘Grafting a number of monomers such as acrylic acid, acrylamide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate and vinyl acetate onto granular corn starch was carried out respectively in aqueous dispersion by using cerie ammonium nitrate as an initiator under nitrogen atmosphere. Conversion of monomer, grafting ratio and grafting efficiency were measured by the method of combining the chemical quantitative analysis with the weight. The adhesive power of the starch graft copolymers to polyester/cotton fiber was evaluated by measuring the breaking strength and elongation of the roving impregnated with the paste. The viscosity change of the size paste before and after grafting was studied. The mechanical properties of polyester/cotton fibre yarn sized by the graft starch were tested. The main conclusions are as follows: (1) monomers which were graft coplymerized onto starch have a significant influence upon the viscosity of the size paste; (2) the adhesive power
基金This project is supported by National Natural Science Foundation of China (No.70071017, No.60074011) the Open-lab of Manufacturing System Engineering, Xi'an Jiaotong University, China.
文摘The capacitated lot sizing and scheduling problem that involves indetermining the production amounts and release dates for several items over a given planning horizonare given to meet dynamic order demand without incurring backloggings. The problem consideringovertime capacity is studied. The mathematical model is presented, and a genetic algorithm (GA)approach is developed to solve the problem. The initial solutions are generated after usingheuristic method. Capacity balancing procedure is employed to stipulate the feasibility of thesolutions. In addition, a technique based on Tabu search (TS) is inserted into the genetic algorithmdeal with the scheduled overtime and help the convergence of algorithm. Computational simulation isconducted to test the efficiency of the proposed hybrid approach, which turns out to improve boththe solution quality and execution speed.
基金the Fund of Anhui Province Science Research Projects,China(No.1106b0105062)the Research Foundation Program of Scientific and Technological Innovation Team of College and University at the Provincial Level of Anhui,China(No.TD200710)
文摘A series of dodecenylsuccinylated starches( DSSs) with different degree of substitution( DS) were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for investigating the influences of starch dodecenylsuccinylation upon the performances such as apparent viscosity and surface tension of starch paste, film behaviors,and adhesion to fibers for warp sizing. It was found that the dodecenylsuccinylation was able to reduce the surface tension of cooked starch paste and enhance the adhesion of starch to polyester fibers. It was also capable of depressing the brittleness of native starch and improving the mechanical behaviours such as breaking elongation and work-to-break of starch film. Initial increase in DS level of dodecenylsuccinylation enhanced these positive effects,while excessively increasing the level resulted in marked reduction in tensile strength of starch film and significant decrement in reaction efficiency. X-ray diffraction patterns of starch films showed the dodecenylsuccinates derivatized onto the backbones of starch depressed the degree of crystallinity of starch film. Based on the paste behaviors, adhesion, and film properties, the dodecenylsuccinylation level is recommended in a range of 0. 015-0. 025 for sizing polyester warps.
基金supported by the National Natural Science Foundation of China (70701008)
文摘Studies show that supply chain cooperation improves supply chain performance. However, it remains a challenge to develop and implement the realistic supply chain cooperation scheme. We investigate a two-echelon supply chain planning problem with capacity acquisition decision under asymmetric cost and demand information. A simple negotiation-based coordination mechanism is developed to synchronize production/order strategies of a supplier and a buyer. The coordination scheme shows how the supplier and the buyer modify their production and order policy in order to find a joint economic lot sizing plan, which saves the overall supply chain cost. The allocation of the cooperation benefit is determined by negotiation. Due to the complexity of the multiple periods, multiple level supply chain lot sizing with capacity decision, a heuristic algorithm is developed to find coordination solutions. Finally, the results of the numerical study indicate the performance of supply chain coordination scheme.
文摘The hollow parts formed with cross-wedge rolling (CWR) have a wide application in many fields, such as architecture and automobile, etc. But the finished configuration of part’s cross section was always ellipse and it was hard to make it satisfied with traditional forming process. This paper proposed a FEM model of hollow workpiece of CWR in the sizing process, and simulated the deformation condition using the ANSYS program. Three kinds of parts with different wall thickness were calculated. Some stress and strain fields of the deformed hollow parts at various conditions are gained. The influence of wall thickness on the distribution of stress and strain was analyzed. The paper also found two phenomena, which never have been seen at traditional experiment, and author tried to give some explanations. The ANSYS program provided the relationship between the tolerance of the deformed workpiece and the deforming parameter. It is helpful to design the sizing dies of a new precise forming process of hollow parts on the CWR. The new process that designed through the information of FEM improved the accuracy of hollow parts on CWR. It proved the validity and practicability of numerical simulation.
基金The Foundation of Talented Persons in Anhui Province(No.2002Z036)
文摘A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition upon the performance such as apparent viscosity,film behaviors,and adhesion capacity to fibers for warp sizing operation.The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method,the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength,breaking elongation,solution time and hygroscopic capacity.It was found that the viscosity,adhesion capability,glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio.Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance.A favorable mole ratio of vinyl acetate or acrylamide was found to be 45∶55.Based on this mole ratio,the adhesion capability and film behaviors of the sizing agent reach their maximal values simultaneously.This demonstrates that the sizing agent should be synthesized under this copolymer composition from the viewpoint of adhesion and film behaviors.
基金This work was supported by International Co-operation Project of Fujian Province(99-I-5).
文摘Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy (XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retain more rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine (PAAm) and polyvinylamine (PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate (PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.
基金financially supported by the National Natural Science Foundation of China (No. 51903237)Beijing Natural Science Foundation (No. 2222091)
文摘Sizing treatment has shown great potential in improving the interfacial properties of poly(p-phenylene benzodioxazole)(PBO)fiber-reinforced composites,but is severely limited due to the use of flammable and explosive organic solvents.Herein,a new high-efficiency waterborne sizing agent has been developed by using functionalized carbon nanospheres(CNSs)as a nano-reinforcement.Due to abundant oxygen-containing groups,the CNSs greatly improves the surface activity,wettability,and roughness of the PBO fibers.As a result,the interfacial shear strength of the CNSs sized fiber-reinforced composite increases by 79.6%compared with that of the pristine fiber-reinforced composite.Moreover,the excellent mechanical and thermal properties of the PBO fibers remain almost unchanged after sizing treatment.Thus,this work provides an environmentally friendly and scalable method for constructing a strong interface between the PBO fibers and the matrix resins,which makes sense in promoting the application of PBO fiber-reinforced composites in aerospace and military industries.
文摘Renewable energy sources(RESs)are considered to be reliable and green electric power generation sources.Photovoltaics(PVs)and wind turbines(WTs)are used to provide electricity in remote areas.Optimal sizing of hybrid RESs is a vital challenge in a stand-alone environment.The meta-heuristic algorithms proposed in the past are dependent on algorithm-specific parameters for achieving an optimal solution.This paper proposes a hybrid algorithm of Jaya and a teaching–learning-based optimization(TLBO)named the JLBO algorithm for the optimal unit sizing of a PV–WT–battery hybrid system to satisfy the consumer’s load at minimal total annual cost(TAC).The reliability of the system is considered by a maximum allowable loss of power supply probability(LPSPmax)concept.The results obtained from the JLBO algorithm are compared with the original Jaya,TLBO,and genetic algorithms.The JLBO results show superior performance in terms of TAC,and the PV–WT–battery hybrid system is found to be the most economical scenario.This system provides a cost-effective solution for all proposed LPSPmax values as compared with PV–battery and WT–battery systems.
