Pub Date : 2023-09-03DOI: 10.24200/sci.2023.58865.5937
Ali Kashani, Behrooz Shirgir, Shervin Sayyar
In order to compute level of service and density in weaving segments, the Highway Capacity Manual (HCM) defined for the first time in 2010 a relationship based on a lane change rate to assess the density of the weaving segment. It is critical to accurately estimate lane changing rate in these situations, but field observations in weaving segments shorter than 250 meters in Tehran, Iran revealed a significant difference between the HCM2016 model estimate and field data. The traffic and geometric data collected at 87 (15-minute) intervals from six weaving segments in Tehran were used to develop models for estimating lane changing rate in weaving segments. These 87 intervals were then divided into 69 (terrain data) for equations and 18 (test data) for model comparisons. Weaving volume and weaving segment area are introduced as two independent variables in the optional lane changing rate model of weaving vehicles in this study, with R2=0.74. Furthermore, for a lane-changing model of non-weaving vehicles with R2=0.95, two new variables of non-weaving volume and traffic solidity were defined. Finally, based on the 18 intervals used to test the results, it showed the improvement of the developed models results compared to HCM2016 models.
{"title":"Development of an Appropriate Model for the Optional Lane-changing Rate in Weaving Segments with Short Lengths","authors":"Ali Kashani, Behrooz Shirgir, Shervin Sayyar","doi":"10.24200/sci.2023.58865.5937","DOIUrl":"https://doi.org/10.24200/sci.2023.58865.5937","url":null,"abstract":"In order to compute level of service and density in weaving segments, the Highway Capacity Manual (HCM) defined for the first time in 2010 a relationship based on a lane change rate to assess the density of the weaving segment. It is critical to accurately estimate lane changing rate in these situations, but field observations in weaving segments shorter than 250 meters in Tehran, Iran revealed a significant difference between the HCM2016 model estimate and field data. The traffic and geometric data collected at 87 (15-minute) intervals from six weaving segments in Tehran were used to develop models for estimating lane changing rate in weaving segments. These 87 intervals were then divided into 69 (terrain data) for equations and 18 (test data) for model comparisons. Weaving volume and weaving segment area are introduced as two independent variables in the optional lane changing rate model of weaving vehicles in this study, with R2=0.74. Furthermore, for a lane-changing model of non-weaving vehicles with R2=0.95, two new variables of non-weaving volume and traffic solidity were defined. Finally, based on the 18 intervals used to test the results, it showed the improvement of the developed models results compared to HCM2016 models.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948646","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 : 2023-09-03DOI: 10.24200/sci.2023.60051.6569
Waleed Adel, Hadi Rezazadeh, Mustafa Inc
The presented work aims to develop a novel technique for solving a general form of both linear and nonlinear partial differential equations (PDEs). This technique is based on applying a collocation method with the aid of Bernoulli polynomials and the use of such an algorithm to solve different types of PDEs. The method applies the regular finite difference scheme to convert the model equation into a system of a linear or nonlinear algebraic equation and then this system is solved using a novel iterative technique. Then, by solving this system an unknown coefficient is acquired and an approximate solution for the problems is achieved. Some test results of famous equations including the telegraph, viscous Burger, and modified Burger equations are presented to demonstrate the effectiveness of the proposed algorithm along with a comparison with other related techniques. The method proves to provide accurate results in terms of absolute error and through graphical representation of the solution.
{"title":"On numerical solutions of Telegraph, viscous, and modified Burgers equations via Bernoulli collocation method","authors":"Waleed Adel, Hadi Rezazadeh, Mustafa Inc","doi":"10.24200/sci.2023.60051.6569","DOIUrl":"https://doi.org/10.24200/sci.2023.60051.6569","url":null,"abstract":"The presented work aims to develop a novel technique for solving a general form of both linear and nonlinear partial differential equations (PDEs). This technique is based on applying a collocation method with the aid of Bernoulli polynomials and the use of such an algorithm to solve different types of PDEs. The method applies the regular finite difference scheme to convert the model equation into a system of a linear or nonlinear algebraic equation and then this system is solved using a novel iterative technique. Then, by solving this system an unknown coefficient is acquired and an approximate solution for the problems is achieved. Some test results of famous equations including the telegraph, viscous Burger, and modified Burger equations are presented to demonstrate the effectiveness of the proposed algorithm along with a comparison with other related techniques. The method proves to provide accurate results in terms of absolute error and through graphical representation of the solution.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948652","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 : 2023-09-03DOI: 10.24200/sci.2023.59942.6507
Mehdi Hosseinzadeh, Saber Ghasemi Karaj-Abad, Mehdi Rasizadeh, Mojtaba Abbasian
In this research, a facile strategy was employed for the synthesis of terpolymer derivatives from polystyrene (PSt), polyurethane (PU), poly (methyl methacrylate) (PMMA), and its organo-modified Zn Al LDH (layered double hydroxide) by in situ ATRP. For this purpose, firstly, LDH nanoparticles were modified with sodium dodecyl sulfonate (SDS) by the anion exchange reaction of Zn-Al-LDH. Secondly, PU macroinitiator was obtained from a solvent composed of 9-decen-1-ol and used in controlled graft copolymerization of styrene to afford PU-co-Pst copolymer. Then, the synthesized PU-co-St was brominated by N-bromosuccinimide (NBS) to obtain a copolymer with the bromine group. In the following, living radical polymerization of MMA was done in the presence of brominated PU-co-St and CuBr /Bpy (2, 2’-bipyridine catalyst to prepare the (PMMA-g-PSt-g-PU) terpolymer. Finally, (PMMA-g-PSt-g-PU)/ ZnAl LDH nanocomposite was successfully synthesized by the solution intercalation method. FE-SEM images showed that surface morphologies of Zn-Al (SDS) and Zn-Al-LDH leads to sheet-like and hexagonal morphology. Investigation of thermal properties using DSC and TGA exhibited that the prepared (PMMA-g-PSt-g-PU) /Zn-Al-LDH nanocomposite has a higher thermal stability compared to neat PU. The synthesized terpolymer and (PMMA-g-PSt-g-PU)/ Zn-Al-LDH nanocomposite can be used as a reinforcing agent for polymeric nanocomposites due to its high LDH properties.
本研究以聚苯乙烯(PSt)、聚氨酯(PU)、聚甲基丙烯酸甲酯(PMMA)及其有机改性Zn Al LDH(层状双氢氧化物)为原料，采用原位ATRP法合成了三元共聚物衍生物。为此，首先通过Zn-Al-LDH的阴离子交换反应，用十二烷基磺酸钠(SDS)修饰LDH纳米颗粒。其次，以9-十二-1-醇为溶剂制备PU宏观引发剂，并将其用于苯乙烯的可控接枝共聚制备PU-co- pst共聚物。然后，将合成的PU-co-St用n -溴代琥珀酰亚胺(NBS)溴化，得到与溴基共聚物。在溴化PU-co-St和CuBr /Bpy(2,2 ' -联吡啶催化剂的存在下，对MMA进行了活性自由基聚合，制备了(pmma -g- st -g- pu)三元共聚物。最后，通过溶液插层法制备了(PMMA-g-PSt-g-PU)/ ZnAl LDH纳米复合材料。FE-SEM图像显示，Zn-Al (SDS)和Zn-Al- ldh的表面形貌为片状和六边形。热性能的DSC和TGA研究表明，制备的(pmma -g- st -g-PU) /Zn-Al-LDH纳米复合材料与纯PU相比具有更高的热稳定性。所合成的三元共聚物和(pmma -g- st -g- pu)/ Zn-Al-LDH纳米复合材料具有较高的LDH性能，可作为高分子纳米复合材料的补强剂。
{"title":"Exfoliated Poly (styrene-co-urethane) Grafted - Polymethylmethacrylate /Layered Double Hydroxide Nanocomposite Synthesized by Metal Catalyzed Living Radical Polymerization and Solvent Blending Method","authors":"Mehdi Hosseinzadeh, Saber Ghasemi Karaj-Abad, Mehdi Rasizadeh, Mojtaba Abbasian","doi":"10.24200/sci.2023.59942.6507","DOIUrl":"https://doi.org/10.24200/sci.2023.59942.6507","url":null,"abstract":"In this research, a facile strategy was employed for the synthesis of terpolymer derivatives from polystyrene (PSt), polyurethane (PU), poly (methyl methacrylate) (PMMA), and its organo-modified Zn Al LDH (layered double hydroxide) by in situ ATRP. For this purpose, firstly, LDH nanoparticles were modified with sodium dodecyl sulfonate (SDS) by the anion exchange reaction of Zn-Al-LDH. Secondly, PU macroinitiator was obtained from a solvent composed of 9-decen-1-ol and used in controlled graft copolymerization of styrene to afford PU-co-Pst copolymer. Then, the synthesized PU-co-St was brominated by N-bromosuccinimide (NBS) to obtain a copolymer with the bromine group. In the following, living radical polymerization of MMA was done in the presence of brominated PU-co-St and CuBr /Bpy (2, 2’-bipyridine catalyst to prepare the (PMMA-g-PSt-g-PU) terpolymer. Finally, (PMMA-g-PSt-g-PU)/ ZnAl LDH nanocomposite was successfully synthesized by the solution intercalation method. FE-SEM images showed that surface morphologies of Zn-Al (SDS) and Zn-Al-LDH leads to sheet-like and hexagonal morphology. Investigation of thermal properties using DSC and TGA exhibited that the prepared (PMMA-g-PSt-g-PU) /Zn-Al-LDH nanocomposite has a higher thermal stability compared to neat PU. The synthesized terpolymer and (PMMA-g-PSt-g-PU)/ Zn-Al-LDH nanocomposite can be used as a reinforcing agent for polymeric nanocomposites due to its high LDH properties.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948480","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 : 2023-08-30DOI: 10.24200/sci.2023.62039.7613
Babak Honarbakhsh
Application of Kobayashi potentials (KP) is extended to the electromagnetic (EM) diffraction from the parallel-plate multiport. Standard integral identities are used for problem formulation, without the direct use of Weber-Schafheitlin (WS) integrals. The Fourier function space is exploited for the construction of the governing linear system of equations. A simple strategy is suggested for the evaluation of the required improper integrals. Two-dimensional T- and X-junctions are studied as special cases. Numerical results are validated through convergence test and asymptotic analysis. It is shown that whenever the wave number in the whole problem domain is positive, no real power transfers to the diffracted field in the horizontal section of the aforementioned structures.
{"title":"Diffraction by a Parallel-Plate Multiport Using the Method of Kobayashi Potentials","authors":"Babak Honarbakhsh","doi":"10.24200/sci.2023.62039.7613","DOIUrl":"https://doi.org/10.24200/sci.2023.62039.7613","url":null,"abstract":"Application of Kobayashi potentials (KP) is extended to the electromagnetic (EM) diffraction from the parallel-plate multiport. Standard integral identities are used for problem formulation, without the direct use of Weber-Schafheitlin (WS) integrals. The Fourier function space is exploited for the construction of the governing linear system of equations. A simple strategy is suggested for the evaluation of the required improper integrals. Two-dimensional T- and X-junctions are studied as special cases. Numerical results are validated through convergence test and asymptotic analysis. It is shown that whenever the wave number in the whole problem domain is positive, no real power transfers to the diffracted field in the horizontal section of the aforementioned structures.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136240772","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 : 2023-08-30DOI: 10.24200/sci.2023.60688.6938
Amir Meysam Giahi, Jafar Asgari Marnani, Mohammad Sadegh Rohanimanesh, Hassan Ahmadi
Structural health monitoring of dams is a necessary issue in water supply network. Not identifying the local damages in these super structures and their extension could lead to abrupt and total collapse and impose major life or financial losses. This research investigates the effects of damage on the concrete arch dams and the methods for their detection. For this purpose the finite element model of a concrete arch dam was analyzed using the wavelet transform once by static frequency analysis and the second time when it is subjected to dynamic accelerograms. In the wavelet transform method using the static frequency analysis, cracks were formed on the dam body and the obtained results were compared to those obtained from Modal Assurance Criterion (MAC) method. In the wavelet transform method, by applying dynamic loads, different damage scenarios, including 16 damage locations and 3 damage levels (change in the materials properties) were compared to the healthy state of the dam. In order to process the wavelet transforms the displacements obtained from the modal and dynamic analyses were utilized. The results showed that employing wavelet transform method by applying dynamic loads could better detect the damages.
{"title":"Structural health monitoring of concrete arch dams using the wavelet transform and modal assurance criterion methods","authors":"Amir Meysam Giahi, Jafar Asgari Marnani, Mohammad Sadegh Rohanimanesh, Hassan Ahmadi","doi":"10.24200/sci.2023.60688.6938","DOIUrl":"https://doi.org/10.24200/sci.2023.60688.6938","url":null,"abstract":"Structural health monitoring of dams is a necessary issue in water supply network. Not identifying the local damages in these super structures and their extension could lead to abrupt and total collapse and impose major life or financial losses. This research investigates the effects of damage on the concrete arch dams and the methods for their detection. For this purpose the finite element model of a concrete arch dam was analyzed using the wavelet transform once by static frequency analysis and the second time when it is subjected to dynamic accelerograms. In the wavelet transform method using the static frequency analysis, cracks were formed on the dam body and the obtained results were compared to those obtained from Modal Assurance Criterion (MAC) method. In the wavelet transform method, by applying dynamic loads, different damage scenarios, including 16 damage locations and 3 damage levels (change in the materials properties) were compared to the healthy state of the dam. In order to process the wavelet transforms the displacements obtained from the modal and dynamic analyses were utilized. The results showed that employing wavelet transform method by applying dynamic loads could better detect the damages.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241018","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 : 2023-08-30DOI: 10.24200/sci.2023.60120.6606
Jafar Biazar, hamed Ebrahimi
In this article, two numerical approaches are presented to solve a system of three fractional differential equations that express the pollution of lakes.In our recent study, a new class of hat functions, called quasi-hat functions (QHFs), are constructed.The proposed approaches utilize modified hat functions (MHFs) and quasi-hat functions (QHFs).Fractional-order operational of MHFs and QHFs are used to build algorithms that transform the main problem into a system of six equations with six unknowns and three equations with three unknowns, respectively.Absolute errors of obtained approximate solutions and convergence analysis of the utilized approach will be studied.Finally, three examples are provided to illustrate the capabilities of these algorithms.The pollution monitoring results are reported in some tables and figures for different values of $alpha$.
{"title":"Two new numerical approaches for the fractional distribution of the model of a system of lakes via modified hat and quasi-hat functions","authors":"Jafar Biazar, hamed Ebrahimi","doi":"10.24200/sci.2023.60120.6606","DOIUrl":"https://doi.org/10.24200/sci.2023.60120.6606","url":null,"abstract":"In this article, two numerical approaches are presented to solve a system of three fractional differential equations that express the pollution of lakes.In our recent study, a new class of hat functions, called quasi-hat functions (QHFs), are constructed.The proposed approaches utilize modified hat functions (MHFs) and quasi-hat functions (QHFs).Fractional-order operational of MHFs and QHFs are used to build algorithms that transform the main problem into a system of six equations with six unknowns and three equations with three unknowns, respectively.Absolute errors of obtained approximate solutions and convergence analysis of the utilized approach will be studied.Finally, three examples are provided to illustrate the capabilities of these algorithms.The pollution monitoring results are reported in some tables and figures for different values of $alpha$.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241014","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 : 2023-08-30DOI: 10.24200/sci.2023.59493.6275
Saman Aminbakhsh, Ary Ahmed
Concomitant reduction of cost and duration is recognized as one of the main aspects of construction planning. Expedition of project schedule naturally incurs extra costs due to implementation of more productive and/or high-price construction techniques. Meanwhile, a reduction in time is usually plausible only down to a certain limit, below which renders expeditions either technically or financially unviable. Thus, striking a reasonable balance between project cost and duration remains a desirable yet challenging task for which there has been a myriad of advancements and literature. Despite the many studies associated with this problem – referred to as time-cost trade-off problem (TCTP) – it is observed that only a few exercise TCTPs with generalized logical relationships. This observation holds despite the fact that generalized precedence relationships are imperative to introduce parallelism and to secure a realistic overlap among the activities. In this regard, a Simulated Annealing-based Genetic Algorithm as proposed herein, is specifically designed to provide the capability of exerting TCTPs with properly overlapped activities. Efficiency of this algorithm is tested over a wide range of problems and its performance is validated over a large-scale real-case construction project. Results of the hybridized GA indicate fast and robust convergence to high-quality solutions.
{"title":"Optimization-based Scheduling of Construction Projects with Generalized Precedence Relationships: A Real-Life Case Study","authors":"Saman Aminbakhsh, Ary Ahmed","doi":"10.24200/sci.2023.59493.6275","DOIUrl":"https://doi.org/10.24200/sci.2023.59493.6275","url":null,"abstract":"Concomitant reduction of cost and duration is recognized as one of the main aspects of construction planning. Expedition of project schedule naturally incurs extra costs due to implementation of more productive and/or high-price construction techniques. Meanwhile, a reduction in time is usually plausible only down to a certain limit, below which renders expeditions either technically or financially unviable. Thus, striking a reasonable balance between project cost and duration remains a desirable yet challenging task for which there has been a myriad of advancements and literature. Despite the many studies associated with this problem – referred to as time-cost trade-off problem (TCTP) – it is observed that only a few exercise TCTPs with generalized logical relationships. This observation holds despite the fact that generalized precedence relationships are imperative to introduce parallelism and to secure a realistic overlap among the activities. In this regard, a Simulated Annealing-based Genetic Algorithm as proposed herein, is specifically designed to provide the capability of exerting TCTPs with properly overlapped activities. Efficiency of this algorithm is tested over a wide range of problems and its performance is validated over a large-scale real-case construction project. Results of the hybridized GA indicate fast and robust convergence to high-quality solutions.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241016","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}
This paper presents the natural convection around a tilted hot cylinder immersed in Casson fluid and enclosed by a square container. The parameters of Casson fluid are set to be (0.1≤η ≤ 1.0), aspect ratio (0.1≤AR ≤ 0.7), tilt angle (0^°≤γ ≤ 90^° ) and Rayleigh number (10^3≤Ra ≤ 10^6) are inspected to reveal their influences on Casson fluid flow and heat transfer. The governing equations were solved with COMSOL Multiphysics 5.6 software. The walls of the enclosure and the cylinder are fixed as T_c and T_h. Findings are delineated as stream functions, isothermal contours, and average Nusselt numbers. The study reveals that for the range of η, AR and Ra investigated, the rate of heat transfer of the enclosure wall increases with increasing η, AR and Ra; while for the heated rectangular obstacle, the rate of heat transfer decreases with AR growth but improves with increasing η and Ra. At Ra=106, γ increment results in heat transfer enhancement for the enclosure and cylinder walls. For Ra in the interval of 10^3≤Ra ≤ 10^5, the response of the thermal profiles of both the rectangular cylinder and enclosure walls to cylinder orientation depends on the value of Ra and γ considered.
{"title":"Analysis of Natural Convective Flow of Casson Fluid around an Inclined Rectangular Cylinder","authors":"Olalekan Adebayo Olayemi, Tomisin Favour Ajide, Adebowale Martins Obalalu, Muneer A. Ismael","doi":"10.24200/sci.2023.60747.6968","DOIUrl":"https://doi.org/10.24200/sci.2023.60747.6968","url":null,"abstract":"This paper presents the natural convection around a tilted hot cylinder immersed in Casson fluid and enclosed by a square container. The parameters of Casson fluid are set to be (0.1≤η ≤ 1.0), aspect ratio (0.1≤AR ≤ 0.7), tilt angle (0^°≤γ ≤ 90^° ) and Rayleigh number (10^3≤Ra ≤ 10^6) are inspected to reveal their influences on Casson fluid flow and heat transfer. The governing equations were solved with COMSOL Multiphysics 5.6 software. The walls of the enclosure and the cylinder are fixed as T_c and T_h. Findings are delineated as stream functions, isothermal contours, and average Nusselt numbers. The study reveals that for the range of η, AR and Ra investigated, the rate of heat transfer of the enclosure wall increases with increasing η, AR and Ra; while for the heated rectangular obstacle, the rate of heat transfer decreases with AR growth but improves with increasing η and Ra. At Ra=106, γ increment results in heat transfer enhancement for the enclosure and cylinder walls. For Ra in the interval of 10^3≤Ra ≤ 10^5, the response of the thermal profiles of both the rectangular cylinder and enclosure walls to cylinder orientation depends on the value of Ra and γ considered.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241017","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 : 2023-08-30DOI: 10.24200/sci.2023.58931.5973
Sepehr Saeidi, Zahra Amini
Gasoline is one of the essential commodities in today's societies and its price can affect different aspects of citizens' lives. This article studies the impacts of the sudden increase in gasoline price on the volume of intercity traffic at national and provincial scales, along with the changes in driving speed distribution and the percentage of speeding violations. The studied period includes four months in two consecutive years. Data was collected from more than 2400 loop detectors placed on the roads of 31 provinces of Iran. This data is used for implementing Regression Discontinuity Design (RDD) on traffic volume and speeding violation percentage. Statistical measures of speed distribution are also used to examine changes in driving speed. According to the literature, the optimal driving speed for fuel consumption is about 50 to 70 km/h. This study showed a 7.4% increase in the probability of driving in the 50 to 70 km/h range after the price increase. Also, according to research results, the volume of intercity traffic and the percentage of speeding violations has decreased due to the rise in gasoline price.
{"title":"Analyzing the Impacts of Gasoline Price Change on Nationwide Trip Demand and Drivers’ Behavior Using Regression Discontinuity Design","authors":"Sepehr Saeidi, Zahra Amini","doi":"10.24200/sci.2023.58931.5973","DOIUrl":"https://doi.org/10.24200/sci.2023.58931.5973","url":null,"abstract":"Gasoline is one of the essential commodities in today's societies and its price can affect different aspects of citizens' lives. This article studies the impacts of the sudden increase in gasoline price on the volume of intercity traffic at national and provincial scales, along with the changes in driving speed distribution and the percentage of speeding violations. The studied period includes four months in two consecutive years. Data was collected from more than 2400 loop detectors placed on the roads of 31 provinces of Iran. This data is used for implementing Regression Discontinuity Design (RDD) on traffic volume and speeding violation percentage. Statistical measures of speed distribution are also used to examine changes in driving speed. According to the literature, the optimal driving speed for fuel consumption is about 50 to 70 km/h. This study showed a 7.4% increase in the probability of driving in the 50 to 70 km/h range after the price increase. Also, according to research results, the volume of intercity traffic and the percentage of speeding violations has decreased due to the rise in gasoline price.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136240875","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 : 2023-08-30DOI: 10.24200/sci.2023.61098.7139
Ali Belhocine, N. Stojanovic, O. I. Abdullah
In this modest work, we present a numerical study of the phenomenon of laminar natural convection in a vertical plate, whose wall was maintained at a constant temperature.It was assumed that the boundary layer problem was initially given in a two-dimensional flow even though the physical properties of the fluid were considered to be constant except for the density change with the temperature.The governing equations of the model have been transformed and simplified into a non-linear system of ordinary differential equations (ODE) through the use of similarity variables which we were able to solve numerically using the Runge-Kutta method. This method has better opted for the numerical resolution of this system which was developed in FORTRAN code on the computer. The numerical results of the model were presented in tabular form and the velocity and temperature profiles for various Prandtl numbers were analyzed and depicted graphically. Also, the expressions of the mean heat transfer rate and the average Nusselt number for the whole plate were obtained in the analysis. The results were compared at the end with the numerical results obtained in the literature, showing that they were in good agreement.
{"title":"Numerical simulation of laminar flow and free convection heat transfer from an isothermal vertical flat plate","authors":"Ali Belhocine, N. Stojanovic, O. I. Abdullah","doi":"10.24200/sci.2023.61098.7139","DOIUrl":"https://doi.org/10.24200/sci.2023.61098.7139","url":null,"abstract":"In this modest work, we present a numerical study of the phenomenon of laminar natural convection in a vertical plate, whose wall was maintained at a constant temperature.It was assumed that the boundary layer problem was initially given in a two-dimensional flow even though the physical properties of the fluid were considered to be constant except for the density change with the temperature.The governing equations of the model have been transformed and simplified into a non-linear system of ordinary differential equations (ODE) through the use of similarity variables which we were able to solve numerically using the Runge-Kutta method. This method has better opted for the numerical resolution of this system which was developed in FORTRAN code on the computer. The numerical results of the model were presented in tabular form and the velocity and temperature profiles for various Prandtl numbers were analyzed and depicted graphically. Also, the expressions of the mean heat transfer rate and the average Nusselt number for the whole plate were obtained in the analysis. The results were compared at the end with the numerical results obtained in the literature, showing that they were in good agreement.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136240873","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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