Pub Date : 2023-06-26DOI: 10.24200/sci.2023.59375.6205
H. Hojabri
Conventional multi–stage AC/DC/DC, AC/DC/AC, DC/DC/DC, and DC/DC/AC converters are two ports converters used to connect a resource or load to an AC or DC grid. To connect several loads or resources to a grid, these converters can easily be extended to a multi– port converter through a common DC–link, with simplified control and a reduced number of active switches. However, DC–link huge energy storage component increases the converter volume and cost and reduces its lifetime and reliability. On the other hand, most of the resources with these types of converters have fault ride–through problems and the DC–link voltage increases during the grid–side faults. The indirect matrix converter is a two–port high–frequency AC–link (HFAC) converter without any intermediate energy storage component, which can be used to connect just a single source or load to a grid. In this paper, a generalized extension of a two–port indirect matrix converter (and the other HFAC converters) to a multi–port converter is proposed. The modulation method, voltage and current gains, and the reactive power limitation of the proposed structure are also presented. Performances of the proposed structure and its modulation strategy are verified through simulation in MATLAB/SIMULINK environment.
{"title":"Multi–Port High–Frequency AC–Link and Indirect Matrix Converters: A Generalized Structure","authors":"H. Hojabri","doi":"10.24200/sci.2023.59375.6205","DOIUrl":"https://doi.org/10.24200/sci.2023.59375.6205","url":null,"abstract":"Conventional multi–stage AC/DC/DC, AC/DC/AC, DC/DC/DC, and DC/DC/AC converters are two ports converters used to connect a resource or load to an AC or DC grid. To connect several loads or resources to a grid, these converters can easily be extended to a multi– port converter through a common DC–link, with simplified control and a reduced number of active switches. However, DC–link huge energy storage component increases the converter volume and cost and reduces its lifetime and reliability. On the other hand, most of the resources with these types of converters have fault ride–through problems and the DC–link voltage increases during the grid–side faults. The indirect matrix converter is a two–port high–frequency AC–link (HFAC) converter without any intermediate energy storage component, which can be used to connect just a single source or load to a grid. In this paper, a generalized extension of a two–port indirect matrix converter (and the other HFAC converters) to a multi–port converter is proposed. The modulation method, voltage and current gains, and the reactive power limitation of the proposed structure are also presented. Performances of the proposed structure and its modulation strategy are verified through simulation in MATLAB/SIMULINK environment.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78826819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.24200/sci.2023.59391.6213
Iman Farzin, Mohammadhossein Abbasi, A. Mahpour
ABSTRACT
摘要
{"title":"How does the environmental concerns affect the satisfaction of BRT and Metro users? A moderator analysis","authors":"Iman Farzin, Mohammadhossein Abbasi, A. Mahpour","doi":"10.24200/sci.2023.59391.6213","DOIUrl":"https://doi.org/10.24200/sci.2023.59391.6213","url":null,"abstract":"ABSTRACT","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72827117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.60237.6682
M. Dehghan, A. Moosaie, Mohammad Zamani Nejad
In this article, a novel spectral method based on the integral transform and finite element (FE) method is introduced for nonlinear thermal analysis of a hollow cylinder under asymmetric boundary excitations. The material properties are temperature-dependent and vary in terms of spatial coordinates. This dependency makes the problem to be nonlinear. The intended nonlinear heat conduction equation is discretized using finite elements in the radial direction. Fast Fourier transform (FFT) technique with the uniform distribution of the harmonics in the circumferential direction, is used to discretize the periodic domain and boundary conditions. The use of the FFT algorithm is accompanied by a significant save in computational times and efforts. In such problems, the Pseudo-spectral technique, as an evolved model of the spectral method, is utilized whenever the material properties vary in terms of the periodic variables or there exists a nonlinear term. The convolution sum technique is appropriately used to transform the nonlinear terms in the Fourier space. Thermal boundary conditions at the inner surface of the cylinder are considered in asymmetrical form. In compliance with the other analytical and numerical solutions, the present mixed-method benefits from the fast rate of convergence and high accuracy.
{"title":"A Mixed Pseudo-spectral FFT-FE Method for Asymmetric Nonlinear Heat Transfer of a Functionally Graded Hollow Cylinder","authors":"M. Dehghan, A. Moosaie, Mohammad Zamani Nejad","doi":"10.24200/sci.2023.60237.6682","DOIUrl":"https://doi.org/10.24200/sci.2023.60237.6682","url":null,"abstract":"In this article, a novel spectral method based on the integral transform and finite element (FE) method is introduced for nonlinear thermal analysis of a hollow cylinder under asymmetric boundary excitations. The material properties are temperature-dependent and vary in terms of spatial coordinates. This dependency makes the problem to be nonlinear. The intended nonlinear heat conduction equation is discretized using finite elements in the radial direction. Fast Fourier transform (FFT) technique with the uniform distribution of the harmonics in the circumferential direction, is used to discretize the periodic domain and boundary conditions. The use of the FFT algorithm is accompanied by a significant save in computational times and efforts. In such problems, the Pseudo-spectral technique, as an evolved model of the spectral method, is utilized whenever the material properties vary in terms of the periodic variables or there exists a nonlinear term. The convolution sum technique is appropriately used to transform the nonlinear terms in the Fourier space. Thermal boundary conditions at the inner surface of the cylinder are considered in asymmetrical form. In compliance with the other analytical and numerical solutions, the present mixed-method benefits from the fast rate of convergence and high accuracy.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78265354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.60206.6665
S. Pujari, Alekya Pilla, S. Subramonian, Daniel Mandrumaka
Using a hand lay-up approach, both orange peel and coconut coir fibres are used in particulate form with an epoxy matrix to create partly green biodegradable composites. The findings indicate great opportunities for employing these natural fibres. The thermal conductivity of orange peel and coconut-coir epoxy composites was measured experimentally for various volume fractions of particulate fibres. The experimental findings show that as fibre concentration increases, thermal conductivity decreases. Experimental data are compared to theoretical models to determine the change in thermal conductivity with fibre amount fraction. There was a clear correlation between the hypotheses and the actual results. Regression analysis using Python programming is also done for the prediction of the thermal properties of particulate orange peel and coconut-coir fibre composites. It is observed that coir fibre composites outperformed the orange peel, indicating that the coir fibre composite is a proper thermal insulator that can be used in many industries, like the automotive industry, buildings, and steam pipes, to reduce heat transfer and thereby save a lot of energy.
{"title":"Python programming predictions of Thermal Behavioral Aspects of Orange Peel and Coconut-Coir Reinforced Epoxy Composites","authors":"S. Pujari, Alekya Pilla, S. Subramonian, Daniel Mandrumaka","doi":"10.24200/sci.2023.60206.6665","DOIUrl":"https://doi.org/10.24200/sci.2023.60206.6665","url":null,"abstract":"Using a hand lay-up approach, both orange peel and coconut coir fibres are used in particulate form with an epoxy matrix to create partly green biodegradable composites. The findings indicate great opportunities for employing these natural fibres. The thermal conductivity of orange peel and coconut-coir epoxy composites was measured experimentally for various volume fractions of particulate fibres. The experimental findings show that as fibre concentration increases, thermal conductivity decreases. Experimental data are compared to theoretical models to determine the change in thermal conductivity with fibre amount fraction. There was a clear correlation between the hypotheses and the actual results. Regression analysis using Python programming is also done for the prediction of the thermal properties of particulate orange peel and coconut-coir fibre composites. It is observed that coir fibre composites outperformed the orange peel, indicating that the coir fibre composite is a proper thermal insulator that can be used in many industries, like the automotive industry, buildings, and steam pipes, to reduce heat transfer and thereby save a lot of energy.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81861847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.60960.7090
Mohammad Ali Zonoobi, Hamid Haghshenas Gorgani, Dorin Javaherneshan
Considering many advantages of 3D printing of polymers using Fused Deposition Modeling (FDM) technique and its service nature, achieving maximum customer satisfaction is very important. The satisfaction of each particular customer may be obtained by providing one or more different outputs of this process, which may not have the same weights. This paper concentrates on multi-objective optimization of three response variables, including tensile strength, dimensional accuracy, and production cost. Eight FDM process parameters containing orientation, layer thickness, infill density, nozzle temperature, print speed, number of shells, infill pattern, and print position have been selected. For carrying out experimental studies, specimens were designed based on Taguchi L27 and manufactured according to ASTM D368-( Ⅰ ) using Polylactic Acid (PLA). Then the signal-to-noise ratio is calculated, and the mathematical regression model of all outputs is obtained. Finally, an intuitive optimal Pareto front is presented to the customer rather than a single point. By repeating the proposed algorithm for eight other customers, the average satisfaction number of 88.56% indicates the efficiency of this method.
{"title":"Experimental investigation and multi-objective optimization of FDM process parameters for mechanical strength, dimensional accuracy, and cost using a hybrid algorithm","authors":"Mohammad Ali Zonoobi, Hamid Haghshenas Gorgani, Dorin Javaherneshan","doi":"10.24200/sci.2023.60960.7090","DOIUrl":"https://doi.org/10.24200/sci.2023.60960.7090","url":null,"abstract":"Considering many advantages of 3D printing of polymers using Fused Deposition Modeling (FDM) technique and its service nature, achieving maximum customer satisfaction is very important. The satisfaction of each particular customer may be obtained by providing one or more different outputs of this process, which may not have the same weights. This paper concentrates on multi-objective optimization of three response variables, including tensile strength, dimensional accuracy, and production cost. Eight FDM process parameters containing orientation, layer thickness, infill density, nozzle temperature, print speed, number of shells, infill pattern, and print position have been selected. For carrying out experimental studies, specimens were designed based on Taguchi L27 and manufactured according to ASTM D368-( Ⅰ ) using Polylactic Acid (PLA). Then the signal-to-noise ratio is calculated, and the mathematical regression model of all outputs is obtained. Finally, an intuitive optimal Pareto front is presented to the customer rather than a single point. By repeating the proposed algorithm for eight other customers, the average satisfaction number of 88.56% indicates the efficiency of this method.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77422463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.61665.7429
F. Babazadeh, M. Ahmadi-pajouh, Seyyed MohammadReza Hashemi Golpayegani
– The specification of stretching and folding properties, particularly in time series, is of substantial interest. This study is sought to perceive the relationship between stretching and folding and irregular discontinuities in hand motion trajectories during target tracking tasks. In this regard, a new method is proposed based on compiling physiological characteristics and hand motion dynamics’ geometrical traits. Thus, five tracking conditions are designed in which participants are instructed to track different target motion patterns. In these experiments, sinusoidal and trapezoidal target movements with frequencies of 0.1 and 0.3 Hz, as well as pseudo-periodic target motion created by summing two sinusoids with frequencies of 0.117 and 0.278 Hz, are used as visual targets. The results illustrate that nonuniform discontinuities are noticeable properties of the hand motion trajectory. Also, the largest Lyapunov exponent, correlation dimension, and fractal dimension corroborate that the tracking attractor is low-dimensional and chaotic. Moreover, the results are compared with the curvature-based method, and its modified version is presented by taking advantage of the proposed method. As a result, through the suggested method, stretching and folding points are well discerned regardless of discontinuities. This method can deal with the systems with intermittency in both times-and state space.
{"title":"A novel stretching and folding characterization method based on geometrical and physiological traits of chaotic and intermittent tracking signals","authors":"F. Babazadeh, M. Ahmadi-pajouh, Seyyed MohammadReza Hashemi Golpayegani","doi":"10.24200/sci.2023.61665.7429","DOIUrl":"https://doi.org/10.24200/sci.2023.61665.7429","url":null,"abstract":"– The specification of stretching and folding properties, particularly in time series, is of substantial interest. This study is sought to perceive the relationship between stretching and folding and irregular discontinuities in hand motion trajectories during target tracking tasks. In this regard, a new method is proposed based on compiling physiological characteristics and hand motion dynamics’ geometrical traits. Thus, five tracking conditions are designed in which participants are instructed to track different target motion patterns. In these experiments, sinusoidal and trapezoidal target movements with frequencies of 0.1 and 0.3 Hz, as well as pseudo-periodic target motion created by summing two sinusoids with frequencies of 0.117 and 0.278 Hz, are used as visual targets. The results illustrate that nonuniform discontinuities are noticeable properties of the hand motion trajectory. Also, the largest Lyapunov exponent, correlation dimension, and fractal dimension corroborate that the tracking attractor is low-dimensional and chaotic. Moreover, the results are compared with the curvature-based method, and its modified version is presented by taking advantage of the proposed method. As a result, through the suggested method, stretching and folding points are well discerned regardless of discontinuities. This method can deal with the systems with intermittency in both times-and state space.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74087881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.61463.7321
Maryam Askari, O. Ahmadi, Younes Javid
Control charts are one of the critical tools for process monitoring. Test statistics are computed as a function of sample means in control charts for monitoring the process mean. In this study, these functions are modeled by filters. These filters have essential properties in both time and frequency domains. In previous studies, only their properties in the time domain have been considered. Thus, the resulting filters have sub-optimal performance. This study investigates the optimal design of these filters for monitoring the process mean. The behavior of these filters is analyzed not only in the time domain but also in the frequency domain. Properties such as stability are considered in designing this filter. An optimization model is designed and solved using a Genetic Algorithm to minimize the Average Run Length. The proposed optimal filter is compared with other control charts using simulation studies. Results showed the high speed of the proposed filter in detecting shifts in the process mean. The proposed optimal filter is also used to monitor the oil price of the OPEC basket. The results showed that shifts were detected at the right time using the proposed optimal filter.
{"title":"Constructing a Sensitive Control Chart to Monitor Process Mean using Optimal Filter: Time-Frequency Analysis Approach","authors":"Maryam Askari, O. Ahmadi, Younes Javid","doi":"10.24200/sci.2023.61463.7321","DOIUrl":"https://doi.org/10.24200/sci.2023.61463.7321","url":null,"abstract":"Control charts are one of the critical tools for process monitoring. Test statistics are computed as a function of sample means in control charts for monitoring the process mean. In this study, these functions are modeled by filters. These filters have essential properties in both time and frequency domains. In previous studies, only their properties in the time domain have been considered. Thus, the resulting filters have sub-optimal performance. This study investigates the optimal design of these filters for monitoring the process mean. The behavior of these filters is analyzed not only in the time domain but also in the frequency domain. Properties such as stability are considered in designing this filter. An optimization model is designed and solved using a Genetic Algorithm to minimize the Average Run Length. The proposed optimal filter is compared with other control charts using simulation studies. Results showed the high speed of the proposed filter in detecting shifts in the process mean. The proposed optimal filter is also used to monitor the oil price of the OPEC basket. The results showed that shifts were detected at the right time using the proposed optimal filter.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73505309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.60165.6637
Soroosh Kamali, S. Dehghan, M. Najafgholipour, M. A. Hadianfard
In this paper, the accuracy and stability of an implicit numerical method (ζ-method) is investigated. It is shown that ζ-method presents high accuracy and efficiency for the dynamic response analysis by assuming a sinusoidal interpolation function for acceleration between two successive time steps. Assuming a sinusoidal distribution of acceleration results in similar types of equations for velocity and displacement since the integration of a sine term contains sine and cosine terms. For this method, a parameter (denoted as ζ) is used as the frequency of the sinusoidal interpolation function which significantly affects the accuracy and stability of the method. The equations and derivations are presented in detail and the best value for ζ is obtained through multi-objective optimization procedures to minimize the errors. The accuracy and stability of the method have been investigated in terms of period elongation, amplitude decay, and spectral radius. Finally, the method has been evaluated by several numerical examples (linear and nonlinear SDOF, and linear MDOF). In some examples, it was observed that the ζ-method yielded better results than other numerical methods. Moreover, an interpolated version of the method was introduced which was more accurate in comparison with similar methods with equal execution time.
{"title":"Accuracy and stability of a Proposed Implicit Time Integration Method (ζ-Method) Based on a Sinusoidal Interpolation Function for Acceleration","authors":"Soroosh Kamali, S. Dehghan, M. Najafgholipour, M. A. Hadianfard","doi":"10.24200/sci.2023.60165.6637","DOIUrl":"https://doi.org/10.24200/sci.2023.60165.6637","url":null,"abstract":"In this paper, the accuracy and stability of an implicit numerical method (ζ-method) is investigated. It is shown that ζ-method presents high accuracy and efficiency for the dynamic response analysis by assuming a sinusoidal interpolation function for acceleration between two successive time steps. Assuming a sinusoidal distribution of acceleration results in similar types of equations for velocity and displacement since the integration of a sine term contains sine and cosine terms. For this method, a parameter (denoted as ζ) is used as the frequency of the sinusoidal interpolation function which significantly affects the accuracy and stability of the method. The equations and derivations are presented in detail and the best value for ζ is obtained through multi-objective optimization procedures to minimize the errors. The accuracy and stability of the method have been investigated in terms of period elongation, amplitude decay, and spectral radius. Finally, the method has been evaluated by several numerical examples (linear and nonlinear SDOF, and linear MDOF). In some examples, it was observed that the ζ-method yielded better results than other numerical methods. Moreover, an interpolated version of the method was introduced which was more accurate in comparison with similar methods with equal execution time.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80869456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.59793.6429
Seyyed Aziz Seyyed Jifroudi, E. Teimoury, F. Barzinpour
: Agri-food supply chains include several processes, from cropping and harvesting to distribution. Integrating these processes to reduce costs and environmental impact and providing sufficient supply are the main goals of agri-food supply chain management. Rice, a so-called staple food, makes up a significant portion of the human diet worldwide. Due to the importance of rice, this paper proposes a mixed-integer linear programming model for rice supply chain design and planning that considers economic, environmental, and social dimensions. This model determines the optimal strategic and tactical decisions in the rice supply chain, including cropping pattern, supplier selection, and the location and capacity of new milling centers with parboiling technology. The model considers different rice varieties and irrigation water requirements of crops. Also, it investigates the benefits of renting as well as offering a partnership agreement to independent farmers. A case study of Iran farmlands is employed to show the applicability and advantages of the proposed model for the rice supply chain. To solve the proposed multi-objective model, the ɛ -constraint method is applied. The results indicate that opening milling centers with parboiling technology is profitable for the supply chain. Moreover, entering a partnership agreement is much more profitable than renting farmlands.
{"title":"A sustainable rice supply chain planning from the farm to the table: a case study","authors":"Seyyed Aziz Seyyed Jifroudi, E. Teimoury, F. Barzinpour","doi":"10.24200/sci.2023.59793.6429","DOIUrl":"https://doi.org/10.24200/sci.2023.59793.6429","url":null,"abstract":": Agri-food supply chains include several processes, from cropping and harvesting to distribution. Integrating these processes to reduce costs and environmental impact and providing sufficient supply are the main goals of agri-food supply chain management. Rice, a so-called staple food, makes up a significant portion of the human diet worldwide. Due to the importance of rice, this paper proposes a mixed-integer linear programming model for rice supply chain design and planning that considers economic, environmental, and social dimensions. This model determines the optimal strategic and tactical decisions in the rice supply chain, including cropping pattern, supplier selection, and the location and capacity of new milling centers with parboiling technology. The model considers different rice varieties and irrigation water requirements of crops. Also, it investigates the benefits of renting as well as offering a partnership agreement to independent farmers. A case study of Iran farmlands is employed to show the applicability and advantages of the proposed model for the rice supply chain. To solve the proposed multi-objective model, the ɛ -constraint method is applied. The results indicate that opening milling centers with parboiling technology is profitable for the supply chain. Moreover, entering a partnership agreement is much more profitable than renting farmlands.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78768292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.24200/sci.2023.61247.7220
A. Nikkhoo, Shirin Banihashemi, K. Kiani
This paper is aimed to examine the dynamics of cracked thin rectangular plates subjected to a moving non-stationary random load. A random load is considered with a constant mean value, a constant moving velocity, and five different covariance patterns namely the white noise, constant, exponential, cosine wave, and exponential cosine covariance. Accordingly, an intact plate’s orthogonal polynomials in combination with the well-known corner functions are employed to explore the mechanical behavior of the cracked plate. As the non-dimensional deflection values, the functions of the squared mean values are obtained for the damped and undamped cracked plates at different points. Then an inclusive parametric study is performed to explore effects of the inclined crack angles and the crack lengths on the non-dimensional functions of squared mean values at middle point of the undamped and damped cracked plates. Based on the obtained results, there are non-monotonous nonlinear relations between increasing the incline crack angles as well as the crack lengths and the non-dimensional functions of squared mean values. Furthermore, it is found that in the exponential covariance cases, the effects of increasing crack angles and lengths on the non-dimensional squared mean values are profounder than the other four patterned covariance cases.
{"title":"On non-stationary response of cracked thin rectangular plates acted upon by a moving random force","authors":"A. Nikkhoo, Shirin Banihashemi, K. Kiani","doi":"10.24200/sci.2023.61247.7220","DOIUrl":"https://doi.org/10.24200/sci.2023.61247.7220","url":null,"abstract":"This paper is aimed to examine the dynamics of cracked thin rectangular plates subjected to a moving non-stationary random load. A random load is considered with a constant mean value, a constant moving velocity, and five different covariance patterns namely the white noise, constant, exponential, cosine wave, and exponential cosine covariance. Accordingly, an intact plate’s orthogonal polynomials in combination with the well-known corner functions are employed to explore the mechanical behavior of the cracked plate. As the non-dimensional deflection values, the functions of the squared mean values are obtained for the damped and undamped cracked plates at different points. Then an inclusive parametric study is performed to explore effects of the inclined crack angles and the crack lengths on the non-dimensional functions of squared mean values at middle point of the undamped and damped cracked plates. Based on the obtained results, there are non-monotonous nonlinear relations between increasing the incline crack angles as well as the crack lengths and the non-dimensional functions of squared mean values. Furthermore, it is found that in the exponential covariance cases, the effects of increasing crack angles and lengths on the non-dimensional squared mean values are profounder than the other four patterned covariance cases.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90666219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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