پژوهشنامه حمل و نقل
سال چهاردهم شماره 2 (پیاپی 51، تابستان 1396)

This paper investigates the feasibility of incorporation of steel slag into the hot mix asphalt. To this end, firstly, physical phases and morphology of steel slag were evaluated through XRD and SEM. Then, seven asphalt mixture types in which different proportions of natural aggregates were substituted with steel slag aggregate were prepared and their volumetric properties and optimum bitumen contents were obtained in accordance with standard Marshall mix design. Moreover, the frictional characteristics of mixes were examined in laboratory and field by means of British pendulum and sand patch methods. Results showed that Marshall Stability, specimen bulk specific weight, and surface friction as well as bitumen consumption and air void content significantly increase as a result of incorporation of steel slag aggregates. However, while Marshall Stability and friction noticeably improved in asphalt mixes in which only coarse part of aggregates were substituted with steel slag aggregates, their air void and bitumen contents remained in acceptable range. Assessing the moisture susceptibility of mixes revealed that mixes containing steel slag are less affected by moisture. In addition, the expansion potential of asphalt mixes in which all the aggregates were replaced with steel slag aggregates found to be less than 1%.

The objective of this research is to design a model for financing the infrastructure road transport projects in Iran through the capital market. The government’s resource deficit and problems in the Iranian banking system have drawn more attention to the capital market as a source of financing. However, an effective use of the capital market rests on the premise that the suitable instruments and institutions exist and apply accurate and transparent rules and regulations.
Based on the mixed method, first, a systematic review was done and half-structured interviews were undertaken with experts until the primary pattern was designed according to the Islamic financial engineering strategy based on satisfaction of the needs. To approve the primary pattern, the Delphi technique was applied using questionnaires and interviews in two parts. In jurisprudential or first part, 8questionnaires were filled, 8fatwas were issued and 4interviews were carried out. Moreover, the issue was approved in the Sharia board of Securities and Exchange Organization of Iran in 4meetings. In the second part or the field of roads, capital market and university, 41questionnaires were filled, 28interviews were carried out and 9group meetings were held. The proposed pattern was approved by the majority of delphi group which is provided in three fields namely instruments, institutions and rules and regulations. The conclusion provided support for the use of Project Jualah, Manfaah and ABS. The operational model of Project Jualah securities was designed as a new Islamic security and approved by experts. In institutions sector the conclusion provided support for the development and use of infrastructure investments funds, custodians and rating agencies as new institutes as well as some actions to be undertaken by the Transportation Fund. Finally in the field of rules and regulations, some changes were proposed to facilitate the financing of road projects through the capital market.

One of the very important issue of pedestrian traffic engineering is. Due to the typical characteristics of personality, reckless behavior expected of young pedestrians not far-fetched. In Iran, a large number of educational centers are located mainly used by teenagers are located on the periphery of suburban roads and pedestrian traffic is frequently seen with this type of institution. Study the interaction of vehicle and pedestrian flow these areas can improve traffic safety and pedestrian facilities to provide useful results. In this study, students as one of the most vulnerable pedestrians in suburban roads were analyzed and recorded video data from the past 3 school students in suburban road in the city of Mahmudabad, Mazandaran province, the three working days of the week were collected. The possibility of pedestrians crossing the street width using SPSS software and logistic regression were used. The results showed that the waiting time before passing away vehicle and the amount of headway on the possibility of crossing the line pedestrians across the road are very effective. Among the factors influencing the amount of headway had the greatest impact on the probability of passing pedestrians.

The vendor managed inventory is one of the common policies in supply chain partnership that allows a vendor to place orders on behalf of the customers according to the constraint that are agreed upon a contractual agreement. In this paper, we propose a two-echelon supply chain model consisting of a single vendor and multiple retailers under the VMI strategy which specifies the space limits of the retailer's warehouses and penalty costs for excess of stocks by considering different transportation modes under different capacities. Then, the resulted non-linear programming model by proposing a heuristic method. In this model, retailers’ order cycles are considered independent of each other and also independent of the vendor’s distribution cycle. Furthermore, the costs associated with the variety of the items and their shipping is considered based on the orders quantities and transportation mode. The aim of the proposed model is to determine the quantity of the orders along with the number of shipments received by retailers and transportation mode such that the total inventory and transportation costs of the chain are minimized jointly, especially for large dimension problems in a short time. The exact optimal solution of this model is obtained by coding in common mathematical optimization software, Lingo, and the result is compared with the result derived from our proposed heuristic method. It is found that the running time of the exact solution is highly affected by the increase in the number of the retailers, and the suggested heuristic method is capable of solving the model in a much less time.

Today, rail transportation as one of the transportation systems, according to advantages such as: environmental protection, low energy consumption and mass movement of passengers and cargo is of great importance and it should always try to maintain this position in the competitive world of transportation. Knowledge is not only assumed as a competitive advantage, but the only source of investment and competitiveness for enterprises. So, organizations should manage their knowledge in a purposive manner and choose a proper strategy on the basis of conditions and for this purpose a lot of organizational factors should be considered. This study aimed to identify and assess the factors affecting the choice of knowledge management strategy in railway of Yazd province. In this study, two groups are examined; the first population is the experts in the field of knowledge management and the second population includes senior managers and staff of railway Yazd with the total number of 120. The kind of study in terms of purpose is applied research, and in terms of data collection is a cross-sectional survey which was conducted by questionnaire. Data analysis was conducted using a combination approach through ANP and fuzzy DEMATEL and the importance of performance and matrix were analyzed with SPSS software and Super Decision. According to the findings, five criteria were as follows: the nature of the organization (0.13), business strategy (0.10), organizational culture (0.095), organizational structure (0.09), manager's conservatism (0.087) and size of the organization (0.079). Due to the high importance and low performance of the nature of the organization and organizational culture, it is better that the railway organization of Yazd province focuses on these two criteria, so in this way allocate resources (time, financial and human capital) effectively and efficiently and improve organizational performance.

The most challenging problems in Supply Chain Management are Facility Location Problem (FLP) and Vehicle Routing Problem (VRP) which considering these two in separate, results in larger costs and planning time. Therefore, Location Routing Problem (LRP) will be addressed by considering VRP and FLP in SCM simultaneously. Company managers always face this problem whether serving each costumer’s demands by one vehicle ends in higher benefits or delivering their demands by more than one vehicle. Answering this issue needs comparing the obtained costs of LRP to the obtained costs of Split Delivery Location Routing Problem (SDLRP). This article presents a mixed-integer linear programming model of SDLRP. The mathematical model of this problem has never been seen in any article. Since it’s a NP-hard problem, the proposed model is run by cplex10.1 software for the small size instances, and for the large size instances, two algorithms, tabu search and simulated annealing are presented. After generating the new experimental instances, the numerical results of problem solving using cplex10.1 software and the suggested algorithms are analyzed. The results show the efficiency of the two algorithms, Tabu search and simulated annealing, and superiority of SA algorithm over TS algorithm, meaning that for most instances, the SA algorithm finds better solutions in a shorter period of time for large size instances. The results also show that considering the assumption of split delivery of customers’ demand leads to final cost reduction, especially when the demand variance is relatively small and the mean demand is greater than half the vehicle capacity but less than three quarters of the vehicle capacity.

In this paper an attempt is made to evaluate the engineering characteristics of asphalt mixtures made ​​with the foam bitumen. In this study, several tests were conducted on 90 samples to evaluate the effect of bitumen content, type of compaction, temperature and curing time on resilient modulus and density of the samples. Marshall and Gyratory compaction method was used to prepare laboratory specimens. According to the results, the ​​ resilient modulus values of mixtures compacted with Marshall Method has a higher density than mixtures compacted with gyratory compactor. The optimum bitumen content of mixtures compacted with Marshall Method are determined corresponding to the maximum density of the samples. To evaluate the Effect of bitumen, it was found that the sensitivity of mixtures prepared with Marshall Method to changes bitumen content is lower than Gyratory compacted samples. In Samples with no curing, resilient modulus of compacted samples by applying higher compacting energy (75 blows Marshall and Gyratory) is lower than mixtures compacted with 50 blow of Marshall. On the other hand, on samples curing in dry condition although the gyratory samples have higher density compare to marshall samples, but it was observed that the samples compacted by the Marshall compactor have higher resilient modulus. In addition in samples curing in wet condition, gyratory samples have higher resilient modulus in higher percentage of bitumen. Finally, due to the relatively low percentage of bitumen in asphalt mixtures made ​​with the foam bitumen, temperature changes in comparison with hot asphalt mixtures have lower effect on the resilient modulus.

In order to improve supply chain performance of ports, create a system of performance measurement is essential. Different pattern assess supply chain performance, define criteria to assess performance that encompasses general indicators to detailed operational indicators. In order to assess supply chain of Imam Khomeini Port, using single-sample t-test to evaluate the significance of supply chain performance (reliability, flexibility, accountability, participation, cost and productivity) from the ship-owners perspective. Shapiro-Wilk test, Kolmogorov-Smirnov test and skewness and kurtosis were used to assess the normality of the data. SPSS software was used to measure statistical analysis. Importance-Performance Analysis model is used to pathology and identify strengths and weaknesses of port supply chain and improve strategies. Identified indicators in the five-item Likert scale questionnaire were distributed among 22 shipping agencies (ship-owners) in Imam Khomeini Port. Matrix importance-performance of the ship-owners is formed after prioritizing the questionnaire indicators. The results indicate that the importance of supply chain performance characteristic, at a high level or are acceptable from the ship-owners perspective. As well as how port respond to the request of the ship-owners or representative and ship safety have utmost importance and duration of the standard organization inspection have least importance from the ship-owners perspective to provide Imam Khomeini Port services.

Moving sand and deposit them on existing tracks in the desert is one of the problems of traditional ballasted rail tracks. This problem resulted in Sand deposition on the railway lines and blocked, trains stopping, derailing, damaging to the structure and flexibility of the track and electrical signals and rolling stock. The thought of this research was to open the path of sand dunes using slab tracks hump , to do so we Analysis the effect of geometry hump in sand transport, optimize the previous plan form, determine the optimum distance of the rails and the floor slab and provide optimum design for sand easy movement with doing fluids essential analysis by software(using numerical model method) and on the basis of the least time that sand deposits on the slab in the direction and wind speed and set to obtain the optimum geometrical dimensions . In this context we have designed and simulated with the knowledge of mechanical fluids (aerodynamics), limits and requirements of designing and loading sleeper railway and also designed slabs, various geometrical shapes hump with the good aerodynamic behavior by using Rhaino software. These figures designed on the size, dimensions and height of the various modeling, such as circular model, minimized model, etc. and stimulated with the fluent simulation software. In this study ,the model parameters which used in assessment analyzing was included Vf (volume of fraction), Mass(sand weight ) and Q( flow of sand ) and V (volume of sand) that resulted in knowing a circular form conical shape with a height of 20 cm (M-C20) as one of the forms with better performance. It sended out the circular cross sections in the first stage of the sand entrance much faster than other forms of combination of normal oval (M-tnx) and minimumed elliptical (M-tmix) and based on the analysis done and study the diagrams, increasing the height of the hump does not necessarily increase the rate of sand passing that showed should be doubly careful in determining the height of the hump.

Slab made of concrete pavement under the load deformation and deformation caused them cracks to the section.in this study the size and thickness of the concrete slab(JRCP) under the Temperature loading and aircraft B777-300in the amount and location and width of cracks were studied to determine the effect of it. The research field studies and library and using design software slab (safe) an analysis model is designed. The results show that by increasing the slab thickness and dimension, the width of the cracks under loads caused by the temperature difference is further reduced in size suggests continuity between the slap is low caused cracks and the increase of leave and the creation of critical that more is. The load carried by the wheel at the edge of the slab and the width of the cracks is more of a load in the middle of the slab and the cracks made linearly. By study the cracks on the slab with variable dimensions and load type shows that the with variable dimensions and load type shows that the width of cracks on the underside of the slab surface is greater than the surface .on the formation of cracks in the wheel load at the section of the slab. Leaving detailed in the center of the surface and spread it around in place of slab surface cracks around the back wheel and the radial shape is formed.

Energy consumption through combustion of fossil fuels is the most important source of Greenhouse Gases (GHG). Since transportation is of the most important energy consumers, investigation on fuel consumption and GHG production to plan for reduction of GHG emission is highly important. Rail plans have a critical role in transportation planning. So, the aim of this study is to investigate the reduction of GHG emission through two scenarios: 20years operation of understudy rail projects, and having not them; through two activity-mode share- fuel intensity- fuel type, and UNFCCC method. Results show that having not rail projects produces 44 Billion tons of CO2 equivalents. While, the first scenario’s GHG emission is half of the seconds. Also, difference between results of the two methods is just 4% which confirms the results.

Every year many bridges during river floods are destroyed due to local piers and abutments scouring. Several methods have already been proposed and applied to reduce and control the depth of scour. For instance using riprap, collar, piles in front of piers, slot at piers, cables, submerged plates and modified pier shape. In the current study, the local scouring around a cylindrical pier has been investigated under normal and using different methods for scour reduction conditions by FLOW-3D numerical model and RNG model is used to estimate the flow turbulence parameters. Evaluating and validating the numerical model are carried out using the results of the physical model. In the following, amount of local scouring behind and in front of the pier in different 11 proposed scour reducing conditions is compared with solo pier. Applying riprap condition with 13% scouring of solo pier has the lowest scouring and using solo pile with half pier diameter in upstream with 26% scouring of solo pier has the highest scouring.

Using the computer simulation is one of the most important current tools for traffic engineering analysis. Simulation means to conduct the desired tests, test the results and compare them with the real system, and in case of positive results, apply it in reality; of course doing all these without requiring to the construction of the real system, without disturbing the real system, without concerning about the destruction of the real system, and in fact, without any losses to the real system. This research is conducted by using library studies – taking notes – and analyzing them as well as simulating and designing the desired construction. The aim of this study is to improve the access networks in the medium-sized cities and the case study is the city of Sanandaj, the center of Kurdistan province. The traffic volume of Azadi square, the main square located in the central core of the city along with the squares, intersections around the area have been studied, and the current conditions and three proposed scenarios have been simulated by means of Aimsun software. In comparing the networks (the proposed scenarios and the current condition), we can conclude that in some intersections, the traffic load of that point cannot be reduced by changing the timing of traffic lights; Maybe by constructing the interchange, the speed of vehicles will not increase significantly, but it can create a smooth traffic and bring comfort and peace for the respected drivers and citizens, these are the main aim of this study.

One of the important techniques that can help organizations to achieve their goals is systems analysis technique. This paper is the results of a research project. It analyzes the wagon system management of railway of the Islamic Republic of Iran. Wagon management system consists of two-sub systems, namely, domestic cars and foreign cars management systems. In this paper, the distribution and trend of foreign cars has been analyzed. In order to select a methodology, we have reviewed some methodologies and finally structured systems analysis and design methodology (SSADM) has been selected. This methodology has six main phases. The two first phases, namely, investigation of the current environment and business system options have been implemented. We have implemented of it. After analyzing the current situation and documenting and evaluating, the problems and requirements of a new system have been determined. Based on the identified problems and needs, measures to improve the present system and the desired situation model are designed.