In the present paper,the numerical solution of It?type stochastic parabolic equation with a timewhite noise process is imparted based on a stochastic finite difference scheme.At the beginning,an implicit stochastic fi...In the present paper,the numerical solution of It?type stochastic parabolic equation with a timewhite noise process is imparted based on a stochastic finite difference scheme.At the beginning,an implicit stochastic finite difference scheme is presented for this equation.Some mathematical analyses of the scheme are then discussed.Lastly,to ascertain the efficacy and accuracy of the suggested technique,the numerical results are discussed and compared with the exact solution.展开更多
The potential of copper recovery from flotation tailings was experimentally investigated using a laboratory-mixing tank. The experiments were performed with solid weight percentages of 30 wt%, 35 wt%, 40 wt% and 45 wt...The potential of copper recovery from flotation tailings was experimentally investigated using a laboratory-mixing tank. The experiments were performed with solid weight percentages of 30 wt%, 35 wt%, 40 wt% and 45 wt% in water. The measurements revealed that adding sulfuric acid all at once to the tank rapidly increased the efficiency of the leaching process, which was attributed to the rapid change in the acid concentration. The rate of iron dissolution from tailings was less than when the acid was added gradually. The sample with 40 wt% solid is recommended as an appropriate feed for the recovery of copper. The adaptive neural fuzzy system(ANFIS) was also used to predict the copper recovery from flotation tailings. The back-propagation algorithm and least squares method were applied for the training of ANFIS. The validation data was also applied to evaluate the performance of these models. Simulation results revealed that the testing results from these models were in good agreement with the experimental data.展开更多
In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction t...In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction time, the quantity and rate of gas uptake, and storage capacity） were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of l-5 wt%, and the mixture of SDS ＋ TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS ＋ TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.展开更多
The effect of synthesized nanostructures,including graphene oxide,chemically reduced graphene oxide with sodium dodecyl sulfate(SDS),chemically reduced graphene oxide with polyvinylpyrrolidone,and multi-walled carbon ...The effect of synthesized nanostructures,including graphene oxide,chemically reduced graphene oxide with sodium dodecyl sulfate(SDS),chemically reduced graphene oxide with polyvinylpyrrolidone,and multi-walled carbon nanotubes,on the kinetics of methane hydrate formation was investigated in this work.The experiments were carried out at a pressure of 4.5 MPa and a temperature of 0 ℃ in a batch reactor.By adding nanostructures,the induction time decreases,and the shortest induction time appeares at certain concentrations of reduced graphene oxide with SDS and graphene oxide,that is,at a concentration of 360 ppm for reduced graphene oxide with SDS and 180 ppm for graphene oxide,with a 98% decrease in induction time compared to that in pure water.Moreover,utilization of carbon nanostructures increases the amount and the rate of methane consumed during the hydrate formation process.Utilization of multi-walled carbon nanotubes with a concentration of 90 ppm showes the highest amount of methane consumption.The amount of methane consumption increases by 173% in comparison with that in pure water.The addition of carbon nanostructures does not change the storage capacity of methane hydrate in the hydrate formation process,while the percentage of water conversion to hydrate in the presence of carbon nanotubes increases considerably,the greatest value of which occurres at a 90 ppm concentration of carbon nanotubes,that is,a 253% increase in the presence of carbon nanotubes compared to that of pure water.展开更多
Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmosphe...Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmospheric conditions.In this research,seismic fragility curves were developed for precast concrete frames with a cast-in-situ concrete shear-wall,concerning the important issues of modeling the precast beam-column joints,construction quality,and soil type effects.For this purpose,the incremental dynamic analysis(IDA)was conducted for three-dimensional models of 3-,5-,and 8-story buildings under two record sets corresponding to soil types C and D of the NEHRP code.Beam-column joints were modeled using nonlinear rotational springs with rigid links with respect to the finite size of the joint panel.Results demonstrate that the Weibull distribution can be fitted to the damage state capacities better than the lognormal distribution at the intensities that are more than one standard deviation away from the median damage capacity.The seismic vulnerability of precast structures increases at all damage states as the height of the building increases.It is also observed that soil type has almost no considerable effect on the fragility curve parameters for all damage states considered herein.展开更多
Accurate estimation of liquid thermal conductivity is highly necessary to appropriately design equipments in different industries. Respect to this necessity, in the current investigation a feed-forward artificial neur...Accurate estimation of liquid thermal conductivity is highly necessary to appropriately design equipments in different industries. Respect to this necessity, in the current investigation a feed-forward artificial neural network(ANN) model is examined to correlate the liquid thermal conductivity of normal and aromatic hydrocarbons at the temperatures range of 257–338 K and atmospheric pressure. For this purpose, 956 experimental thermal conductivities for normal and aromatic hydrocarbons are collected from different previously published literature.During the modeling stage, to discriminate different substances, critical temperature(Tc), critical pressure(Pc)and acentric factor(ω) are utilized as the network inputs besides the temperature. During the examination, effects of different transfer functions and number of neurons in hidden layer are investigated to find the optimum network architecture. Besides, statistical error analysis considering the results obtained from available correlations and group contribution methods and proposed neural network is performed to reliably check the feasibility and accuracy of the proposed method. Respect to the obtained results, it can be concluded that the proposed neural network consisted of three layers namely, input, hidden and output layers with 22 neurons in hidden layer was the optimum ANN model. Generally, the proposed model enables to correlate the thermal conductivity of normal and aromatic hydrocarbons with absolute average relative deviation percent(AARD), mean square error(MSE), and correlation coefficient(R^2) of lower than 0.2%, 1.05 × 10^(-7) and 0.9994, respectively.展开更多
This article presents an efficient parallel processing approach for solving the opti- mal control problem of nonlinear composite systems. In this approach, the original high-order coupled nonlinear two-point boundary ...This article presents an efficient parallel processing approach for solving the opti- mal control problem of nonlinear composite systems. In this approach, the original high-order coupled nonlinear two-point boundary value problem （TPBVP） derived from the Pontrya- gin＇s maximum principle is first transformed into a sequence of lower-order deeoupled linear time-invariant TPBVPs. Then, an optimal control law which consists of both feedback and forward terms is achieved by using the modal series method for the derived sequence. The feedback term specified by local states of each subsystem is determined by solving a ma- trix Riccati differential equation. The forward term for each subsystem derived from its local information is an infinite sum of adjoint vectors. The convergence analysis and parallel processing capability of the proposed approach are also provided. To achieve an accurate feedforward-feedbaek suboptimal control, we apply a fast iterative algorithm with low com- putational effort. Finally, some comparative results are included to illustrate the effectiveness of the proposed approach.展开更多
With the spread of English language around the world and its status as an international language, the need for more communication is felt. One pivoting aspect of this communication is the role of culture which can con...With the spread of English language around the world and its status as an international language, the need for more communication is felt. One pivoting aspect of this communication is the role of culture which can contribute to the success of communication at the global level and the co-construction of identities as individuals from different parts of the world get into interactions. Thus, the role of materials developed for learning English, especially the local ones, in the improvement of individuals＇ intercultural competence is significant. New course books for learning English at Iranian secondary schools entitled Prospect series have been developed recently. Thus, the purpose of the present study was to evaluate the first and the second books of this series in light of Byram＇s model of Intercultural Communicative Competence （1CC）. Based on this model, ICC consists of three dimensions of attitude, knowledge, skills, and five saviors of knowledge, attitude, discovery, interaction, and critical thinking. To do the evaluation of the course books, the checklist developed based on these five saviors was used to evaluate the tasks for each unit of the books. The evaluation was done separately by each of the researchers in the study and inter-rater reliability showed a high level of Cronbach alpha. The findings indicated that about 90 percent of the activities of Prospect 1 and Prospect 2 lack the skills required for improving English language learners＇ ICC. They mostly focus on Iranian culture which might have been improved via learners＇ first language as well. This might imply the need for the adaptation of Prospect series activities in light of ICC so that Iranian English language learners can take advantage of their communication with the rest of the world.展开更多
Knowing and analyzing the ＂culture of learning and teaching＂ in a coursebook or series of course books can contribute to teachers＇ and students＇ success in the educational and pedagogical goals and objectives. Cul...Knowing and analyzing the ＂culture of learning and teaching＂ in a coursebook or series of course books can contribute to teachers＇ and students＇ success in the educational and pedagogical goals and objectives. Cultures of learning and teaching refer to the perspectives of teachers and learners towards learning and teaching. Most of the research studies conducted in this field have referred to values and attitudes related to good learning and teaching as reflected through observations, interviews and questionnaires. However, just few studies have examined this term with regard to language teaching materials, and course books. Thus, the purpose of the present study was to introduce, investigate, and analyze the cultures of learning and teaching in Iranian secondary school course books entitled Prospect series. Based on the model used in this study, the cultures of learning and teaching in Prospect series were investigated as reflected in their external features including aims and objectives cited in the introduction, tables of content, and layout of the students＇ books, and internal features including task instructions and visual images in students＇ book plus the instructions in the teacher＇s book. Each of these features as well as the pedagogical issues of the Prospect series were provided and elaborated.展开更多
With the globalization of English, the macro and micro cultures of the users of English around the world interact intensively. Considering these conditions, the local and global cultural interface seems an important i...With the globalization of English, the macro and micro cultures of the users of English around the world interact intensively. Considering these conditions, the local and global cultural interface seems an important issue which needs to be clarified in the materials and books used for learning English. Thus, the focus of this study was to explore the language learning policy of the new Iranian English course book at high schools, Prospect 1, recently published and taught for a year in Iran, in light of globalization and culture. This qualitative study was conducted through carrying out semi-structured interviews. The participants of this study were 30 teachers of Ministry of Education, who had the experience of teaching Prospect I for a year and they were mostly chosen from Mashhad and the rest from other cities of Khorasan province, Iran. The interview contained four main questions which were posed to the teachers. The findings of the study indicate that the language learning policy of Iran need to pay more attention to the learners＇ intercultural communicative competence because it mainly attempts at teaching English language focusing on the home culture in the Iranian context. The article ends with some pedagogical implications and more recommendations for developing research studies.展开更多
Health-related quality of life (HRQOL) has not been investigated among Iranian industrial workers. The present paper aimed to study the influence of the socio-demographic, health and work-related factors on HRQOL amon...Health-related quality of life (HRQOL) has not been investigated among Iranian industrial workers. The present paper aimed to study the influence of the socio-demographic, health and work-related factors on HRQOL among Iranian industrial workers. In this cross-sectional study, participants were 280 workers of two factories. The Persian version of World Health Organization Quality of Life-Brief (WHOQOL-BREF) was used to assess the HRQOL. A questionnaire was developed to assess the socio-demographic, health and work-related factors. Results showed that the means (SD) of physical health, psychological health, social relationships, and environment domains of HRQOL were 13.2 (2.7), 13.3 (2.6), 14.2 (3.5) and 12.6 (2.5), respectively. A multiple linear regression showed that types of job, exercise activity, working schedule, sleep quality, smoking, and conflict between work and social life were significantly associated with physical health domain;whereas, working schedule, marital status, working demand, sleep quality, BMI, and conflict between work and individual life were significantly associated with psychological health domain. Working schedule, working demand, sleep quality, conflict between work and individual life, and having children over two years were significantly associated with social relationship domain;however, working demand, working schedule, smoking, sleep quality, working hour, job satisfaction, marital status and exercise activity were significantly associated with environment domain. Collectively, work-related factors including unhealthy working conditions, unsafe working environments, long working hours, irregular working schedules, and the lack of occupational training may negatively influence the HRQOL of workers. To improve workers’ HRQOL, intervention programs should focus on improving work environment, working schedule, occupational training and restricting working hours.展开更多
In this work,a system of three masses on the vertices of equilateral triangle is investigated.This system is known in the literature as a planar system.We first give a description to the system by constructing its cla...In this work,a system of three masses on the vertices of equilateral triangle is investigated.This system is known in the literature as a planar system.We first give a description to the system by constructing its classical Lagrangian.Secondly,the classical Euler-Lagrange equations(i.e.,the classical equations of motion)are derived.Thirdly,we fractionalize the classical Lagrangian of the system,and as a result,we obtain the fractional Euler-Lagrange equations.As the final step,we give the numerical simulations of the fractional model,a new model which is based on Caputo fractional derivative.展开更多
Reliability optimization plays an important role in design, operation and management of the industrial systems. System reliability can be easily enhanced by improving the reliability of unreliable components and/or by...Reliability optimization plays an important role in design, operation and management of the industrial systems. System reliability can be easily enhanced by improving the reliability of unreliable components and/or by using redundant configuration with subsystems/components in parallel. Redundancy Allocation Problem (RAP) was studied in this research. A mixed integer programming model was proposed to solve the problem, which considers simultaneously two objectives under several resource constraints. The model is only for the hierarchical series-parallel systems in which the elements of any subset of subsystems or components are connected in series or parallel and constitute a larger subsystem or total system. At the end of the study, the performance of the proposed approach was evaluated by a numerical example.展开更多
This report aims to reduce the benzene in a mixture of benzene and toluene as a model reaction using catalytic hydrogenation. In this research, we developed a series of catalysts with different supports such as Ni/HMS...This report aims to reduce the benzene in a mixture of benzene and toluene as a model reaction using catalytic hydrogenation. In this research, we developed a series of catalysts with different supports such as Ni/HMS, Ni/HZSM-5, Ni/HZSM5-HMS, Ni/Al2O3 and Ni/SiO2. Kinetic of this reaction was investigated under various hydrogen and benzene pressures. For more study, two kinetic models have also been selected and tested to describe the kinetics for this reaction. Both used models, the power law and Langmuir-Hinshelwood, provided a good fit toward the experimental data and allowed to determine the kinetic parameters. Among these catalysts, Ni/Al2O3 showed the maximum benzene conversion （99.19%） at 130℃ for benzene hydrogenation. The lowest toluene conversion was observed for Ni/SiO2. Furthermore, this catalyst presented high selectivity to benzene （75.26%） at 130℃. The catalytic performance （activity, selectivity and stability） and kinetics evaluations were shown that the Ni/SiO2 is an effective catalyst to hydrogenate benzene. It seems that the surface properties particularly pore size are effective parameter compared to other factors such as acidity and metal dispersion in this process.展开更多
Relationship between reading performance and academic achievement is theoretically predictable. However, this relationship could be higher among early childhood bilingual (ECBL) students than monolingual peers. For ev...Relationship between reading performance and academic achievement is theoretically predictable. However, this relationship could be higher among early childhood bilingual (ECBL) students than monolingual peers. For evaluating this claim, two groups of randomly selected female second graders (150 Farsi speaking and 150 Farsi and Turkish speaking) were tested and compared on these characteristics. The measures used were Kormi-Nouri and associates’ tests of reading performance. Moreover, academic achievement was defined to be the average of scores obtained by students at their final school exams in Math, Science and Farsi. Analysis of regression was then performed to determine which construct served as the best predictor of academic achievement in both groups. Based on the results, ECBL girls were superior to their monolingual (ML) counterparts in all three areas. Findings also show that reading performance was a strong predictor of school achievement for both groups.展开更多
Moving objects tracking is one of the most used categories in the realm of machine vision that has attracted attention of so many researchers in recent decades. Video tracking has various applications in military indu...Moving objects tracking is one of the most used categories in the realm of machine vision that has attracted attention of so many researchers in recent decades. Video tracking has various applications in military industries, protective systems and machine vision. Target tracking algorithms vary according to their usages. In this paper, it has been attempted to discuss and analyze mobile target tracking techniques and algorithms in Marine.展开更多
The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state ...The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state masses and magnetic moments of doubly heavy Ω and Ξ baryons.In the heavy quark limit,we introduce a simple form of the universal Isgur-Wise function used as the transition form factor and then investigate the exclusive b→c semileptonic decay widths and branching fractions for 1/2→1/2 baryon transitions.Our obtained results are in agreement with other theoretical predictions.展开更多
In this study,a harmonic oscillator with position-dependent mass is investigated.Firstly,as an introduction,we give a full description of the system by constructing its classical Lagrangian;thereupon,we derive the rel...In this study,a harmonic oscillator with position-dependent mass is investigated.Firstly,as an introduction,we give a full description of the system by constructing its classical Lagrangian;thereupon,we derive the related classical equations of motion such as the classical Euler–Lagrange equations.Secondly,we fractionalize the classical Lagrangian of the system,and then we obtain the corresponding fractional Euler–Lagrange equations(FELEs).As a final step,we give the numerical simulations corresponding to the FELEs within different fractional operators.Numerical results based on the Caputo and the Atangana-Baleanu-Caputo(ABC)fractional derivatives are given to verify the theoretical analysis.展开更多
Heat conduction in multi-layer and composite materials is one of the fundamental heat transfer problems in many industrial applications.Due to different materials types,interface conditions,and various geometries of t...Heat conduction in multi-layer and composite materials is one of the fundamental heat transfer problems in many industrial applications.Due to different materials types,interface conditions,and various geometries of these laminates,the heat conduction mechanism is more complicated than that of one-layer isotropic media.Analytical solutions are the best ways to study and understand such problems in depth.In this study,different existing analytical solutions for heat conduction in multi-layer and composite materials are reviewed and classified in rectangular,cylindrical,spherical,and conical coordinates.Applied boundary conditions,internal heat source,and thermal contact resistance as the most critical parameters in the solution complexity investigated in the literature,are discussed and summarized in different tables.Various types of multi-layer structures such as isotropic,anisotropic,orthotropic,and reinforced laminates are included in this study.It is found that although more than half a century has passed since the beginning of the research on heat transfer in multi-layer composites,new researches that can help with a better understanding in this area are still being offered.The challenges and shortcomings in this area are also discussed to guide future researches.展开更多
In this study,natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time(MRT)Lattice Boltzmann method(LBM).We consider a copper/water na...In this study,natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time(MRT)Lattice Boltzmann method(LBM).We consider a copper/water nanofluid filling a porous cavity.For simulating the temperature and flow fields,D2Q5 and D2Q9 lattices are utilized respectively,and the effects of different Darcy numbers(Da)(0.001-0.1)and various Rayleigh numbers(Ra)(10^(3)-10^(5))for porosity(ε)between 0.4 and 0.9 have been considered.Phase deviation(θ)changed from 0 toπand the volume fraction of nanoparticles(∅)varied from 0 to 6%.The present results show a good agreement with the previous works,thus confirming the reliability the new numerical method proposed in this paper.It is indicated that the heat transfer rate increases at increasing Darcy number,porosity,Rayleigh number,the volume fraction of nanoparticles and phase deviation.However,the most sensitive parameter is the Rayleigh number.The maximum Nusselt deviation is 10%,32%and 33%for Ra=10^(3),10^(4) and 10^(5),respectively,withε=0.4 toε=0.9.It can be concluded that the effect of Darcy number on the heat transfer rate increases at increasing Rayleigh number,yielding a maximum enhancement of the average Nusselt number around 12%and 61%for Ra=10^(3) and Ra=10^(5),respectively.展开更多
文摘In the present paper,the numerical solution of It?type stochastic parabolic equation with a timewhite noise process is imparted based on a stochastic finite difference scheme.At the beginning,an implicit stochastic finite difference scheme is presented for this equation.Some mathematical analyses of the scheme are then discussed.Lastly,to ascertain the efficacy and accuracy of the suggested technique,the numerical results are discussed and compared with the exact solution.
文摘The potential of copper recovery from flotation tailings was experimentally investigated using a laboratory-mixing tank. The experiments were performed with solid weight percentages of 30 wt%, 35 wt%, 40 wt% and 45 wt% in water. The measurements revealed that adding sulfuric acid all at once to the tank rapidly increased the efficiency of the leaching process, which was attributed to the rapid change in the acid concentration. The rate of iron dissolution from tailings was less than when the acid was added gradually. The sample with 40 wt% solid is recommended as an appropriate feed for the recovery of copper. The adaptive neural fuzzy system(ANFIS) was also used to predict the copper recovery from flotation tailings. The back-propagation algorithm and least squares method were applied for the training of ANFIS. The validation data was also applied to evaluate the performance of these models. Simulation results revealed that the testing results from these models were in good agreement with the experimental data.
基金financial support from the Iran National Science Foundation
文摘In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction time, the quantity and rate of gas uptake, and storage capacity） were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of l-5 wt%, and the mixture of SDS ＋ TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS ＋ TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.
文摘The effect of synthesized nanostructures,including graphene oxide,chemically reduced graphene oxide with sodium dodecyl sulfate(SDS),chemically reduced graphene oxide with polyvinylpyrrolidone,and multi-walled carbon nanotubes,on the kinetics of methane hydrate formation was investigated in this work.The experiments were carried out at a pressure of 4.5 MPa and a temperature of 0 ℃ in a batch reactor.By adding nanostructures,the induction time decreases,and the shortest induction time appeares at certain concentrations of reduced graphene oxide with SDS and graphene oxide,that is,at a concentration of 360 ppm for reduced graphene oxide with SDS and 180 ppm for graphene oxide,with a 98% decrease in induction time compared to that in pure water.Moreover,utilization of carbon nanostructures increases the amount and the rate of methane consumed during the hydrate formation process.Utilization of multi-walled carbon nanotubes with a concentration of 90 ppm showes the highest amount of methane consumption.The amount of methane consumption increases by 173% in comparison with that in pure water.The addition of carbon nanostructures does not change the storage capacity of methane hydrate in the hydrate formation process,while the percentage of water conversion to hydrate in the presence of carbon nanotubes increases considerably,the greatest value of which occurres at a 90 ppm concentration of carbon nanotubes,that is,a 253% increase in the presence of carbon nanotubes compared to that of pure water.
文摘Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmospheric conditions.In this research,seismic fragility curves were developed for precast concrete frames with a cast-in-situ concrete shear-wall,concerning the important issues of modeling the precast beam-column joints,construction quality,and soil type effects.For this purpose,the incremental dynamic analysis(IDA)was conducted for three-dimensional models of 3-,5-,and 8-story buildings under two record sets corresponding to soil types C and D of the NEHRP code.Beam-column joints were modeled using nonlinear rotational springs with rigid links with respect to the finite size of the joint panel.Results demonstrate that the Weibull distribution can be fitted to the damage state capacities better than the lognormal distribution at the intensities that are more than one standard deviation away from the median damage capacity.The seismic vulnerability of precast structures increases at all damage states as the height of the building increases.It is also observed that soil type has almost no considerable effect on the fragility curve parameters for all damage states considered herein.
文摘Accurate estimation of liquid thermal conductivity is highly necessary to appropriately design equipments in different industries. Respect to this necessity, in the current investigation a feed-forward artificial neural network(ANN) model is examined to correlate the liquid thermal conductivity of normal and aromatic hydrocarbons at the temperatures range of 257–338 K and atmospheric pressure. For this purpose, 956 experimental thermal conductivities for normal and aromatic hydrocarbons are collected from different previously published literature.During the modeling stage, to discriminate different substances, critical temperature(Tc), critical pressure(Pc)and acentric factor(ω) are utilized as the network inputs besides the temperature. During the examination, effects of different transfer functions and number of neurons in hidden layer are investigated to find the optimum network architecture. Besides, statistical error analysis considering the results obtained from available correlations and group contribution methods and proposed neural network is performed to reliably check the feasibility and accuracy of the proposed method. Respect to the obtained results, it can be concluded that the proposed neural network consisted of three layers namely, input, hidden and output layers with 22 neurons in hidden layer was the optimum ANN model. Generally, the proposed model enables to correlate the thermal conductivity of normal and aromatic hydrocarbons with absolute average relative deviation percent(AARD), mean square error(MSE), and correlation coefficient(R^2) of lower than 0.2%, 1.05 × 10^(-7) and 0.9994, respectively.
文摘This article presents an efficient parallel processing approach for solving the opti- mal control problem of nonlinear composite systems. In this approach, the original high-order coupled nonlinear two-point boundary value problem （TPBVP） derived from the Pontrya- gin＇s maximum principle is first transformed into a sequence of lower-order deeoupled linear time-invariant TPBVPs. Then, an optimal control law which consists of both feedback and forward terms is achieved by using the modal series method for the derived sequence. The feedback term specified by local states of each subsystem is determined by solving a ma- trix Riccati differential equation. The forward term for each subsystem derived from its local information is an infinite sum of adjoint vectors. The convergence analysis and parallel processing capability of the proposed approach are also provided. To achieve an accurate feedforward-feedbaek suboptimal control, we apply a fast iterative algorithm with low com- putational effort. Finally, some comparative results are included to illustrate the effectiveness of the proposed approach.
文摘With the spread of English language around the world and its status as an international language, the need for more communication is felt. One pivoting aspect of this communication is the role of culture which can contribute to the success of communication at the global level and the co-construction of identities as individuals from different parts of the world get into interactions. Thus, the role of materials developed for learning English, especially the local ones, in the improvement of individuals＇ intercultural competence is significant. New course books for learning English at Iranian secondary schools entitled Prospect series have been developed recently. Thus, the purpose of the present study was to evaluate the first and the second books of this series in light of Byram＇s model of Intercultural Communicative Competence （1CC）. Based on this model, ICC consists of three dimensions of attitude, knowledge, skills, and five saviors of knowledge, attitude, discovery, interaction, and critical thinking. To do the evaluation of the course books, the checklist developed based on these five saviors was used to evaluate the tasks for each unit of the books. The evaluation was done separately by each of the researchers in the study and inter-rater reliability showed a high level of Cronbach alpha. The findings indicated that about 90 percent of the activities of Prospect 1 and Prospect 2 lack the skills required for improving English language learners＇ ICC. They mostly focus on Iranian culture which might have been improved via learners＇ first language as well. This might imply the need for the adaptation of Prospect series activities in light of ICC so that Iranian English language learners can take advantage of their communication with the rest of the world.
文摘Knowing and analyzing the ＂culture of learning and teaching＂ in a coursebook or series of course books can contribute to teachers＇ and students＇ success in the educational and pedagogical goals and objectives. Cultures of learning and teaching refer to the perspectives of teachers and learners towards learning and teaching. Most of the research studies conducted in this field have referred to values and attitudes related to good learning and teaching as reflected through observations, interviews and questionnaires. However, just few studies have examined this term with regard to language teaching materials, and course books. Thus, the purpose of the present study was to introduce, investigate, and analyze the cultures of learning and teaching in Iranian secondary school course books entitled Prospect series. Based on the model used in this study, the cultures of learning and teaching in Prospect series were investigated as reflected in their external features including aims and objectives cited in the introduction, tables of content, and layout of the students＇ books, and internal features including task instructions and visual images in students＇ book plus the instructions in the teacher＇s book. Each of these features as well as the pedagogical issues of the Prospect series were provided and elaborated.
文摘With the globalization of English, the macro and micro cultures of the users of English around the world interact intensively. Considering these conditions, the local and global cultural interface seems an important issue which needs to be clarified in the materials and books used for learning English. Thus, the focus of this study was to explore the language learning policy of the new Iranian English course book at high schools, Prospect 1, recently published and taught for a year in Iran, in light of globalization and culture. This qualitative study was conducted through carrying out semi-structured interviews. The participants of this study were 30 teachers of Ministry of Education, who had the experience of teaching Prospect I for a year and they were mostly chosen from Mashhad and the rest from other cities of Khorasan province, Iran. The interview contained four main questions which were posed to the teachers. The findings of the study indicate that the language learning policy of Iran need to pay more attention to the learners＇ intercultural communicative competence because it mainly attempts at teaching English language focusing on the home culture in the Iranian context. The article ends with some pedagogical implications and more recommendations for developing research studies.
文摘Health-related quality of life (HRQOL) has not been investigated among Iranian industrial workers. The present paper aimed to study the influence of the socio-demographic, health and work-related factors on HRQOL among Iranian industrial workers. In this cross-sectional study, participants were 280 workers of two factories. The Persian version of World Health Organization Quality of Life-Brief (WHOQOL-BREF) was used to assess the HRQOL. A questionnaire was developed to assess the socio-demographic, health and work-related factors. Results showed that the means (SD) of physical health, psychological health, social relationships, and environment domains of HRQOL were 13.2 (2.7), 13.3 (2.6), 14.2 (3.5) and 12.6 (2.5), respectively. A multiple linear regression showed that types of job, exercise activity, working schedule, sleep quality, smoking, and conflict between work and social life were significantly associated with physical health domain;whereas, working schedule, marital status, working demand, sleep quality, BMI, and conflict between work and individual life were significantly associated with psychological health domain. Working schedule, working demand, sleep quality, conflict between work and individual life, and having children over two years were significantly associated with social relationship domain;however, working demand, working schedule, smoking, sleep quality, working hour, job satisfaction, marital status and exercise activity were significantly associated with environment domain. Collectively, work-related factors including unhealthy working conditions, unsafe working environments, long working hours, irregular working schedules, and the lack of occupational training may negatively influence the HRQOL of workers. To improve workers’ HRQOL, intervention programs should focus on improving work environment, working schedule, occupational training and restricting working hours.
文摘In this work,a system of three masses on the vertices of equilateral triangle is investigated.This system is known in the literature as a planar system.We first give a description to the system by constructing its classical Lagrangian.Secondly,the classical Euler-Lagrange equations(i.e.,the classical equations of motion)are derived.Thirdly,we fractionalize the classical Lagrangian of the system,and as a result,we obtain the fractional Euler-Lagrange equations.As the final step,we give the numerical simulations of the fractional model,a new model which is based on Caputo fractional derivative.
文摘Reliability optimization plays an important role in design, operation and management of the industrial systems. System reliability can be easily enhanced by improving the reliability of unreliable components and/or by using redundant configuration with subsystems/components in parallel. Redundancy Allocation Problem (RAP) was studied in this research. A mixed integer programming model was proposed to solve the problem, which considers simultaneously two objectives under several resource constraints. The model is only for the hierarchical series-parallel systems in which the elements of any subset of subsystems or components are connected in series or parallel and constitute a larger subsystem or total system. At the end of the study, the performance of the proposed approach was evaluated by a numerical example.
文摘This report aims to reduce the benzene in a mixture of benzene and toluene as a model reaction using catalytic hydrogenation. In this research, we developed a series of catalysts with different supports such as Ni/HMS, Ni/HZSM-5, Ni/HZSM5-HMS, Ni/Al2O3 and Ni/SiO2. Kinetic of this reaction was investigated under various hydrogen and benzene pressures. For more study, two kinetic models have also been selected and tested to describe the kinetics for this reaction. Both used models, the power law and Langmuir-Hinshelwood, provided a good fit toward the experimental data and allowed to determine the kinetic parameters. Among these catalysts, Ni/Al2O3 showed the maximum benzene conversion （99.19%） at 130℃ for benzene hydrogenation. The lowest toluene conversion was observed for Ni/SiO2. Furthermore, this catalyst presented high selectivity to benzene （75.26%） at 130℃. The catalytic performance （activity, selectivity and stability） and kinetics evaluations were shown that the Ni/SiO2 is an effective catalyst to hydrogenate benzene. It seems that the surface properties particularly pore size are effective parameter compared to other factors such as acidity and metal dispersion in this process.
文摘Relationship between reading performance and academic achievement is theoretically predictable. However, this relationship could be higher among early childhood bilingual (ECBL) students than monolingual peers. For evaluating this claim, two groups of randomly selected female second graders (150 Farsi speaking and 150 Farsi and Turkish speaking) were tested and compared on these characteristics. The measures used were Kormi-Nouri and associates’ tests of reading performance. Moreover, academic achievement was defined to be the average of scores obtained by students at their final school exams in Math, Science and Farsi. Analysis of regression was then performed to determine which construct served as the best predictor of academic achievement in both groups. Based on the results, ECBL girls were superior to their monolingual (ML) counterparts in all three areas. Findings also show that reading performance was a strong predictor of school achievement for both groups.
文摘Moving objects tracking is one of the most used categories in the realm of machine vision that has attracted attention of so many researchers in recent decades. Video tracking has various applications in military industries, protective systems and machine vision. Target tracking algorithms vary according to their usages. In this paper, it has been attempted to discuss and analyze mobile target tracking techniques and algorithms in Marine.
基金Supported by Kosar University of Bojnord(Grant No.0011191444)。
文摘The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state masses and magnetic moments of doubly heavy Ω and Ξ baryons.In the heavy quark limit,we introduce a simple form of the universal Isgur-Wise function used as the transition form factor and then investigate the exclusive b→c semileptonic decay widths and branching fractions for 1/2→1/2 baryon transitions.Our obtained results are in agreement with other theoretical predictions.
文摘In this study,a harmonic oscillator with position-dependent mass is investigated.Firstly,as an introduction,we give a full description of the system by constructing its classical Lagrangian;thereupon,we derive the related classical equations of motion such as the classical Euler–Lagrange equations.Secondly,we fractionalize the classical Lagrangian of the system,and then we obtain the corresponding fractional Euler–Lagrange equations(FELEs).As a final step,we give the numerical simulations corresponding to the FELEs within different fractional operators.Numerical results based on the Caputo and the Atangana-Baleanu-Caputo(ABC)fractional derivatives are given to verify the theoretical analysis.
基金financial support of the National Natural Science Foundation of China(No.52025061 and No.51961130386)the financial support from the Royal Society-Newton Advanced Fellowship grant(NAF\R1\191163).
文摘Heat conduction in multi-layer and composite materials is one of the fundamental heat transfer problems in many industrial applications.Due to different materials types,interface conditions,and various geometries of these laminates,the heat conduction mechanism is more complicated than that of one-layer isotropic media.Analytical solutions are the best ways to study and understand such problems in depth.In this study,different existing analytical solutions for heat conduction in multi-layer and composite materials are reviewed and classified in rectangular,cylindrical,spherical,and conical coordinates.Applied boundary conditions,internal heat source,and thermal contact resistance as the most critical parameters in the solution complexity investigated in the literature,are discussed and summarized in different tables.Various types of multi-layer structures such as isotropic,anisotropic,orthotropic,and reinforced laminates are included in this study.It is found that although more than half a century has passed since the beginning of the research on heat transfer in multi-layer composites,new researches that can help with a better understanding in this area are still being offered.The challenges and shortcomings in this area are also discussed to guide future researches.
文摘In this study,natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time(MRT)Lattice Boltzmann method(LBM).We consider a copper/water nanofluid filling a porous cavity.For simulating the temperature and flow fields,D2Q5 and D2Q9 lattices are utilized respectively,and the effects of different Darcy numbers(Da)(0.001-0.1)and various Rayleigh numbers(Ra)(10^(3)-10^(5))for porosity(ε)between 0.4 and 0.9 have been considered.Phase deviation(θ)changed from 0 toπand the volume fraction of nanoparticles(∅)varied from 0 to 6%.The present results show a good agreement with the previous works,thus confirming the reliability the new numerical method proposed in this paper.It is indicated that the heat transfer rate increases at increasing Darcy number,porosity,Rayleigh number,the volume fraction of nanoparticles and phase deviation.However,the most sensitive parameter is the Rayleigh number.The maximum Nusselt deviation is 10%,32%and 33%for Ra=10^(3),10^(4) and 10^(5),respectively,withε=0.4 toε=0.9.It can be concluded that the effect of Darcy number on the heat transfer rate increases at increasing Rayleigh number,yielding a maximum enhancement of the average Nusselt number around 12%and 61%for Ra=10^(3) and Ra=10^(5),respectively.
