Search results for: Tehran railway

Authors: Zeinab Amini Moghaddam, Alireza Dehkhodania

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Nowadays, organizations have found a high status in the cultural and social structures of societies. The purpose of current study is to investigate the relationship between organizational climate with job burnout as well as job satisfaction. The research method is descriptive and correlational. The population of the study includes all employees in Tehran Electric Company, which equals 1984 people in 2018. The sampling was performed in the form of a consensus, and all employees were regarded as samples. The data gathering tools consist of three questionnaires of Smith’s Job Satisfaction Questionnaire, Halpin and Craft's Occupational climate, and Maslach and Jackson's Job burnout. The results showed that there was a direct and positive relationship between organizational climate and job burnout, as well as job satisfaction. The organizational climate variable could successfully predict job satisfaction. It was also able to predict job burnout.

Keywords: organizational climate, job burnout, job satisfaction, descriptive, correlational

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Authors: Chul Su Kim, Jun Ku Lee, Won Jun Lee

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The EMU (electric multiple unit) vehicle timer card is a PCB (printed circuit board) for controlling the air-dryer to remove the moisture of the generated air from the air compressor of the braking device. This card is exposed to the lower part of the railway vehicle, so it is greatly affected by the external environment such as temperature and humidity. The main cause of the failure of this timer card is deterioration of soldering area of the PCB surface due to temperature and humidity. Therefore, in the viewpoint of preventive maintenance, it is important to evaluate the reliability of the timer card and predict the replacement cycle to secure the safety of the air braking device is one of the main devices for driving. In this study, the existing and the improved products were evaluated on the reliability through ALT (accelerated life test). In addition, the acceleration factor by the 'Coffin-Manson' equation was obtained, and the remaining lifetime was compared and examined.

Keywords: reliability evaluation, timer card, Printed Circuit Board, Accelerated Life Test

Procedia PDF Downloads 247

Authors: Dimitrios J. Dimitriou, Maria F. Sartzetaki, Anastasia Kalamakidou

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Transport infrastructure assets are key components of the national asset portfolio. The decision to invest in a new infrastructure in transports could take from a few years to some decades. This is mainly because of the need to reserve and spent many capitals, the long payback period, the number of the stakeholders involved in the decision process and –many times- the investment and business risks are high. Decision makers and stakeholders need to define the framework and the outputs of the decision process taking into account the project characteristics, the business uncertainties, and the different expectations. Therefore, the decision assessment framework is an essential challenge linked with the key decision factors meet the stakeholder expectations highlighting project trade-offs, financial risks, business uncertainties and market limitations. This paper examines the decision process for new transport infrastructure projects in cross-border regions, where a wide range of stakeholders with different expectation is involved. According to a consequences analysis systemic approach, the relationship of transport infrastructure development, economic system development and stakeholder expectation is analysed. Adopting the on system of system methodological approach, the decision making the framework, variables, inputs and outputs are defined, highlighting the key shareholder’s role and expectations. The application provides the methodology outputs presenting the proposed decision framework for a strategic railway project in north Greece deals with the upgrade of the existing railway corridor connecting Greece, Turkey, and Bulgaria.

Keywords: system of system decision making, managing decisions for transport projects, decision support framework, defining decision process

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Authors: Milad Alizadeh Galdiani, Jabbar Ali Zakeri

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Lateral movement of CWR ballasted track occurs in sharp curves because of the lack of adequate lateral resistance. Several strategies have been proposed and used for increase the lateral resistance of ballasted tracks, but still there are some problems in tracks with small radius curves. In this paper, a new method has been presented for increase the lateral resistance. This method is using the lateral supports as numerical and field studies. In this paper, the field and laboratory tests have been conducted by using the single tie pressure test (STPT) and track panel loading test (LTPT). Then, their results were compared with the numerical results. The results of numerical and field tests showed that the lateral stiffness of ballasted tracks significantly increased when there were lateral supports in ballasted tracks. Also, the track structure had a bilinear behavior.

Keywords: ballasted railway, Lateral resistance, railway buckling, field and numerical studies

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Authors: Mitra Abtahi, Esmat Nasseri, Morteza Abodllahi

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Introduction: Adequate hydration is necessary for proper physical and mental function. The aim of this study is to determine the consumption of water and all other beverages in children (8-13 years) and adolescents (14-17 years) in Tehran metropolitan city of Iran. Materials and Methods: In this cross-sectional study, 455 children (8-13 years) and 334 adolescents (14-17 years) were retrieved from north, center, and south of Tehran (18 schools). Instrument for data collection consisted of a “demographic and general health” questionnaire and a “7-day fluid record”. Data analyses were performed with SPSS 16 software. Results: The mean total consumption of fluids in school children was 1302 ± 500.6 ml/day. The highest mean intakes were observed for water (666 ± 398 ml/day), followed by milk (239 ± 183 ml/day), regular soft beverages (RSB) (188 ± 148 ml/day), and juices (60 ± 74 ml/day). Water, hot drinks (mainly tea) and soft drinks intake was significantly more in boys than girls. A significantly lower intake of milk and a higher intake of RSB and hot beverages (mainly tea) have been seen among adolescents compared to children. Conclusion: The most important finding is that mean fluid intake of children and adolescents does not meet international adequate intake references for water and fluids. This finding may suggest the necessity of development of the local references. To improve fluid intake habits of children and adolescents, relevant policy making and actions are warranted.

Keywords: adolescents, beverages, children, water

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Authors: S. P. Pradhan, Amulya Ratna Roul

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A number of landslides are occurring during the rainy season along Rayagada-Koraput Railway track for past three years. The track was constructed about 20 years ago. However, the protection measures are not able to control the recurring slope failures now. It leads to a loss to Indian Railway and its passengers ultimately leading to wastage of time and money. The slopes along Rayagada-Koraput track include both rock and soil slopes. The rock types include mainly Khondalite and Charnockite whereas soil slopes are mainly composed of laterite ranging from less weathered to highly weathered laterite. The field studies were carried out in one of the critical slope. Field study was followed by the kinematic analysis to assess the type of failure. Slake Durability test, Uniaxial Compression test, specific gravity test and triaxial test were done on rock samples to calculate and assess properties such as weathering index, unconfined compressive strength, density, cohesion, and friction angle. Following all the laboratory tests, rock mass rating was calculated. Further, from Kinematic analysis and Rock Mass Ratingbasic, Slope Mass Rating was proposed for each slope. The properties obtained were used to do the slope stability simulations using finite element method based modelling. After all the results, suitable protection measures, to prevent the loss due to slope failure, were suggested using the relation between Slope Mass Rating and protection measures.

Keywords: landslides, slope stability, rock mass rating, slope mass rating, numerical simulation

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Authors: G. Santamato, M. Solazzi, A. Frisoli

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Systems for detection of damages in railway pantographs effectively reduce the cost of maintenance and improve time scheduling. In this paper, we present an approach to design a monitoring tool fitting strong customer requirements such as portability and ease of use. Pantograph has been modeled to estimate its dynamical properties, since no data are available. With the aim to focus on suspensions health, a two Degrees of Freedom (DOF) scheme has been adopted. Parameters have been calculated by means of analytical dynamics. A Finite Element Method (FEM) modal analysis verified the former model with an acceptable error. The detection strategy seeks phase-plots topology alteration, induced by defects. In order to test the suitability of the method, leakage in the dashpot was simulated on the lumped model. Results are interesting because changes in phase plots are more appreciable than frequency-shift. Further calculations as well as experimental tests will support future developments of this smart strategy.

Keywords: pantograph models, phase plots, structural health monitoring, damage detection

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Authors: Bahar Salavati Vie Le Sage, Ismaïl Ben Hariz, Flavien Viguier, Sirine Noura Kahil, Audrey Jacquin, Maxime Convert

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The ballast layer plays a key role in railroad maintenance and the geometry of the track structure. Ballast also holds the track in place as the trains roll over it. Track ballast is packed between the sleepers and on the sides of railway tracks. An imbalance in ballast volume on the tracks can lead to safety issues as well as a quick degradation of the overall quality of the railway segment. If there is a lack of ballast in the track bed during the summer, there is a risk that the rails will expand and buckle slightly due to the high temperatures. Furthermore, the knowledge of the ballast quantities that will be excavated during renewal works is important for efficient ballast management. The volume of excavated ballast per meter of track can be calculated based on excavation depth, excavation width, volume of track skeleton (sleeper and rail) and sleeper spacing. Since 2012, SNCF has been collecting 3D points cloud data covering its entire railway network by using 3D laser scanning technology (LiDAR). This vast amount of data represents a modelization of the entire railway infrastructure, allowing to conduct various simulations for maintenance purposes. This paper aims to present an automated method for ballast volume estimation based on the processing of LiDAR data. The estimation of abnormal volumes in ballast on the tracks is performed by analyzing the cross-section of the track. Further, since the amount of ballast required varies depending on the track configuration, the knowledge of the ballast profile is required. Prior to track rehabilitation, excess ballast is often present in the ballast shoulders. Based on 3D laser scans, a Digital Terrain Model (DTM) was generated and automatic extraction of the ballast profiles from this data is carried out. The surplus in ballast is then estimated by performing a comparison between this ballast profile obtained empirically, and a geometric modelization of the theoretical ballast profile thresholds as dictated by maintenance standards. Ideally, this excess should be removed prior to renewal works and recycled to optimize the output of the ballast renewal machine. Based on these parameters, an application has been developed to allow the automatic measurement of ballast profiles. We evaluated the method on a 108 kilometers segment of railroad LiDAR scans, and the results show that the proposed algorithm detects ballast surplus that amounts to values close to the total quantities of spoil ballast excavated.

Keywords: ballast, railroad, LiDAR , cloud point, track ballast, 3D point

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Authors: H. Nejadriahi

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Traditional architecture is a valuable source of inspiration, which needs to be studied and integrated in the contemporary designs for achieving an identifiable contemporary architecture. Traditional architecture of Iran is among the distinguished examples of being contextually responsive, not only by considering the environmental conditions of a region, but also in terms of respecting the socio-cultural values of its context. In order to apply these valuable features to the current designs, they need to be adapted to today's condition, needs and desires. In this paper, the main features of the traditional architecture of Iran are explained to interrogate them in the formation of a contemporary house in Tehran, Iran. Also a table is provided to compare the utilization of the traditional design concepts in the traditional houses and the contemporary example of it. It is believed that such study would increase the awareness of contemporary designers by providing them some clues on maintaining the traditional values in the current design layouts particularly in the residential sector that would ultimately improve the quality of space in the contemporary architecture.

Keywords: contemporary housing design, Iran, Tehran, traditional architecture

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Authors: Hossein Askarinejad, Manicka Dhanasekar

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In railway tracks, two adjacent rails are either welded or connected using bolted jointbars. In recent years the number of bolted rail joints is reduced by introduction of longer rail sections and by welding the rails at location of some joints. However, significant number of bolted rail joints remains in railways around the world as they are required to allow for rail thermal expansion or to provide electrical insulation in some sections of track. Regardless of the quality and integrity of the jointbar and bolt connections, the bending stiffness of jointbars is much lower than the rail generating large deflections under the train wheels. In addition, the gap or surface discontinuity on the rail running surface leads to generation of high wheel-rail impact force at the joint gap. These fundamental weaknesses have caused high rate of failure in track components at location of rail joints resulting in significant economic and safety issues in railways. The mechanical behavior of railway track at location of joints has not been fully understood due to various structural and material complexities. Although there have been some improvements in the methods for analysis of track at jointed rails in recent years, there are still uncertainties concerning the accuracy and reliability of the current methods. In this paper the current methods in analysis of track with a rail joint are critically evaluated and the new advances and recent research outcomes in this area are discussed. This research is part of a large granted project on rail joints which was defined by Cooperative Research Centre (CRC) for Rail Innovation with supports from Australian Rail Track Corporation (ARTC) and Queensland Rail (QR).

Keywords: jointed rails, railway mechanics, track dynamics, wheel-rail interaction

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Authors: Buğra Sinmez

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In some countries, such as China, Turkey, andseveralEuropeanUnionnations, the therailwaypavementstructuralsystem has recently undergonerapid growth as a vital element of the transportation infrastructure, particularlyfortheuse of high-speed trains. It is vitaltoconsiderthe High-SpeedInfrastructureDemandwhendevelopingandconstructingtherailwaypavementstructure. HSRL can create more substantial ldifficultiestotheballastorbaselayer of regularlyusedballastedrailwaypavementsthanstandardrailwaytrains. The deterioration of the theballastorbaselayermayleadtosubstructuredegradation, which might lead to safety concerns and catastrophicincidents. As a result, the efficiency of railways will be impactedbylargecargoesorhigh-speed trains. A railwaypavement construction can be strengthened using geosyntheticmaterials in theballastorfoundationlayer as a countermeasure. However, there is still a need in the literature to quantifytheinfluence of geosynthetic materials, particularlygeogrid, on the mechanical responses of railwaypavementstructuresto HSRL loads which is essential knowledge in supporting the selection of appropriate material and geogridinstallationposition. As a result, the purpose of this research is to see how a geogridreinforcementlayermayaffectthekeyfeatures of a ballastedrailwaypavementstructure, with a particular focus on the materialtypeandgeogridplacementpositionthatmayassistreducethe rate of degradation of the therailwaypavementstructuresystem. Thisstudyusesnumericalmodeling in a genuinerailwaycontexttovalidatethebenefit of geogrid reinforcement. The usage of geogrids in the railway system has been thoroughly researched in the technical literature. Three distinct types of geogrid installed at two distinct positions (i.e.,withintheballastlayer, betweentheballastandthesub-ballast layer) within a railwaypavementconstructionwereevaluatedunder a variety of verticalwheelloadsusing a three-dimensional (3D) finite element model. As a result, fouralternativegeogridreinforcementsystemsweremodeledtoreflectdifferentconditions in the ballastedrailwaysystems (G0: no reinforcement; G1: reinforcedwithgeogridhavingthelowestdensityandYoung'smodulus; G2: reinforcedwithgeogridhavingtheintermediateYoung'smodulusanddensity; G3: reinforcedwithgeogridhavingthegreatestdensityandYoung'smodulus). Themechanicalreactions of the railway, such as verticalsurfacedeflection, maximumprimarystressandstrain, andmaximumshearstress, werestudiedandcomparedbetweenthefourgeogridreinforcementscenariosandfourverticalwheelloadlevels (i.e., 75, 100, 150, and 200 kN). Differences in the mechanical reactions of railwaypavementconstructionsowingtotheuse of differentgeogridmaterialsdemonstratethebenefits of suchgeosynthetics in ballast. In comparison to a non-reinforcedrailwaypavementconstruction, thereinforcedconstructionsfeaturedecreasedverticalsurfacedeflection, maximum shear stress at the sleeper-ballast contact, and maximum main stress at the bottom of the ballast layer. As a result, addinggeogridtotheballastlayerandbetweentheballastandsub-ballast layer in a ballastedrailwaypavementconstruction has beenfoundtolowercriticalshearand main stresses as well as verticalsurfacedeflection.

Keywords: geosynthetics, geogrid, railway, transportation

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Authors: Ghazaleh Monazami Tehrani, Zhamak Monazami Tehrani, Raziyeh Hadavand

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Optimal site selection for temporary housing is one of the most important issues in crisis management. In this research, district six of Tehran city with high frequency and geographical distribution of earthquakes has been selected as a case study for positioning temporary housing after a probable earthquake. For achieving this goal this study tries to identify and evaluate distribution of location according to some standards such as compatible and incompatible urban land uses with utility of GIS and AHP. The results of this study show the most susceptible parts of this region in the center. According to the maps, north eastern part of Kordestan, Shaheed Gomnam intersection possesses the highest pixels value in terms of areal extent, therefore these places are recommended as an optimum site location for construction of emergency evacuation base.

Keywords: optimal site selection, temporary housing , crisis management, AHP, GIS

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Authors: Shamshiri Mitra, Abedi Rahim

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This paper investigates corporate investment behavior and its relationship with ownership structure and financial leverage for the listed company of Tehran stock exchange during 2008-2012. The results show that the concentration of ownership has s significant positive effect on corporate investment. The results for the kind of major owners show that institutional ownership had a positive significant effect and state and individual ownership had negative significant effects on the corporate investment but the effect of corporate ownership was not significant. Furthermore the effect of financial leverage was negative and significant.

Keywords: corporate investment behavior, financial leverage, ownership structure corporate investment behavior

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Authors: Shima Naderi, Abbas Abbaszadeh Shahri

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Energy resources are reachable and affordable in Iran, thus surplus access to fossil fuels besides high level of economic growth leads to serious environmental critical such as pollutants and greenhouse gases in the atmosphere, increase in average degrease and lack of water sources specially in Tehran as a capital city of Iran. As building sector consumes a huge portion of energy, taking actions towards alternative sources of energy as well as conserving non-renewable energy resources and architectural energy saving methods are the fundamental basis for achieving sustainability`s goals. This study tries to explore implantation of both high technologies and traditional issues for reduction of energy demands in buildings of Tehran and introduce some factors and instructions for achieving this purpose. Green and energy efficient buildings such as ZEBs make it possible to preserve natural resources for the next generations by reducing pollution and increasing ecosystem self-recovery. However ZEB is not widely spread in Iran because of its low economic efficiency, it is not viable for a private entrepreneur without the governmental supports. Therefore executing of Architectural Energy Efficiency can be a better option. It is necessary to experience a substructure expansion with respect to traditional residential building style. Renewable energies and passive design which are the substantial part of the history of architecture in Iran can be regenerated and employed as an essential part of designing energy efficient buildings.

Keywords: architectural energy efficiency, passive design, renewable energies, zero energy buildings

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Authors: Muhammad Akmal Putera, Noriyuki Yasufuku, Adel Alowaisy, Ahmad Rifai

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Indonesia’s government has planned a project for a high-speed railway connecting the capital cities, Jakarta and Surabaya, about 700 km. Based on that location, it has been planning construction above the lowland soil region. The lowland soil region comprises cohesive soil with high water content and high compressibility index, which in fact, led to a settlement problem. Among the variety of railway track structures, the adoption of the ballastless track was used effectively to reduce the settlement; it provided a lightweight structure and minimized workspace. Contradictorily, deploying this thin layer structure above the lowland area was compensated with several problems, such as lack of bearing capacity and deflection behavior during traffic loading. It is necessary to combine with ground improvement to assure a settlement behavior on the clayey soil. Reflecting on the assurance of strength increment and working period, those were convinced by adopting methods such as cement-treated soil as the substructure of railway track. Particularly, evaluating mechanical properties in the field has been well known by using the plate load test and cone penetration test. However, observing an increment of mechanical properties has uncertainty, especially for evaluating cement-treated soil on the substructure. The current quality control of cement-treated soils was established by laboratory tests. Moreover, using small strain devices measurement in the laboratory can predict more reliable results that are identical to field measurement tests. Aims of this research are to show an intercorrelation of confining pressure with the initial condition of the Young modulus (E_o), Poisson ratio (υ_o) and Shear modulus (G_o) within small strain ranges. Furthermore, discrepancies between those parameters were also investigated. Based on the experimental result confirmed the intercorrelation between cement content and confining pressure with a power function. In addition, higher cement ratios have discrepancies, conversely with low mixing ratios.

Keywords: amount of cement, elastic zone, high-speed railway, lightweight structure

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Authors: Mahdi Azizzadeh, Ali Nabizadeh

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This paper investigates whether ownership structure has significant effects on dividend policy and the percentage of cash dividend payout ratio in Iranian companies listed on the Tehran Stock Exchange. We use a sample of 300 firm-years for 2010-2014. Results indicate that there is no significant relationship between family ownership and/or institutional ownership and dividend policy. Furthermore, there is no significant relationship between dividend policies in family-owned firms with high or low institutional ownership. However, our empirical test shows that family firms with a low level of institutional investors distribute more cash dividends on average than family firms with a high level of institutional ownership.

Keywords: family ownership, institutional ownership, dividend policy, dividend payout ratio

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Authors: Farideh Gheitasi, Zahra Mirzaei Pour

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Considering mutual interactions of industry and residence in an environmental point of view is essential in effective urban management and all the policies must be made based on the results of these interactions. So, District No 21 of Tehran Municipality (Iran) which is almost industrial combined with some residential area was selected to study the consequences of industrial and residential area neighborhood. In this paper the results of two observations conducted in two timescales in 2010 and 2015, according to completed questionnaires by residents of an industrial region in the study area, were analyzed. The questionnaires contain 19 different environmental parameters considering positive and negative effects of industry on human life. The results of this study show that 96% of the target group in 2010 believed if the companies regard the law, mutual coexistence of industry and residency is possible. While this number decreased to 21% in 2015, which indicates that the problem got worse and people became more unsatisfied with the situation.

Keywords: environment, industry, residence, pollution

Procedia PDF Downloads 286

Authors: Narayanakumar Somasundaram, Venkat Nihit Chirivella, Venkata Dilip Kumar Pasupuleti

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Ajakool, India, has a multi-span bridge that is constructed for rail transport with a maximum operating speed of 100 km/hr. It is a standard RDSO design of a PSC box girder carrying a single railway track. The Structural Health Monitoring System (SHM) is designed and installed to compare and analyze the vibrations and displacements on the bridge due to different live loads from moving trains. The study is conducted for three different spans of the same bridge to understand the health of the elastomeric bearings. Also, to validate the same, a three-dimensional finite element model is developed, and modal analysis is carried out. The proposed methodology can help in detecting deteriorated elastomeric bearings using only wireless tri-accelerometer sensors. Detailed analysis and results are presented in terms of mode shapes, accelerations, displacements, and their importance to each other. This can be implemented with a lot of ease and can be more accurate.

Keywords: dynamic effects, vibration analysis, accelerometer sensors, finite element analysis, structural health monitoring, elastomeric bearing

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Authors: Soha Saad, Jean Bigeon, Florence Ossart, Etienne Sourdille

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Developing better solutions for train rescheduling problems has been drawing the attention of researchers for decades. Most researches in this field deal with minor incidents that affect a large number of trains due to cascading effects. They focus on timetables, rolling stock and crew duties, but do not take into account infrastructure limits. The present work addresses electric infrastructure incidents that limit the power available for train traction, and hence the transportation capacity of the railway system. Rescheduling is needed in order to optimally share the available power among the different trains. We propose a rescheduling process based on dynamic multiphysics railway simulations that include the mechanical and electrical properties of all the system components and calculate physical quantities such as the train speed profiles, voltage along the catenary lines, temperatures, etc. The optimization problem to solve has a large number of continuous and discrete variables, several output constraints due to physical limitations of the system, and a high computation cost. Our approach includes a phase of sensitivity analysis in order to analyze the behavior of the system and help the decision making process and/or more precise optimization. This approach is a quantitative method based on simulation statistics of the dynamic railway system, considering a predefined range of variation of the input parameters. Three important settings are defined. Factor prioritization detects the input variables that contribute the most to the outputs variation. Then, factor fixing allows calibrating the input variables which do not influence the outputs. Lastly, factor mapping is used to study which ranges of input values lead to model realizations that correspond to feasible solutions according to defined criteria or objectives. Generalized Sobol indexes are used for factor prioritization and factor fixing. The approach is tested in the case of a simple railway system, with a nominal traffic running on a single track line. The considered incident is the loss of a feeding power substation, which limits the power available and the train speed. Rescheduling is needed and the variables to be adjusted are the trains departure times, train speed reduction at a given position and the number of trains (cancellation of some trains if needed). The results show that the spacing between train departure times is the most critical variable, contributing to more than 50% of the variation of the model outputs. In addition, we identify the reduced range of variation of this variable which guarantees that the output constraints are respected. Optimal solutions are extracted, according to different potential objectives: minimizing the traveling time, the train delays, the traction energy, etc. Pareto front is also built.

Keywords: optimization, rescheduling, railway system, sensitivity analysis, train timetable

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Authors: S. A. Naeini, A. Khalili

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Nowadays, tunnels with different applications are developed, and most of them are related to subway tunnels. The excavation of shallow tunnels that pass under municipal utilities is very important, and the surface settlement control is an important factor in the design. The study sought to analyze the settlement and also to find an appropriate model in order to predict the behavior of the tunnel in Tehran subway line-3. The displacement in these sections is also determined by using numerical analyses and numerical modeling. In addition, the Adaptive Neuro-Fuzzy Inference System (ANFIS) method is utilized by Hybrid training algorithm. The database pertinent to the optimum network was obtained from 46 subway tunnels in Iran and Turkey which have been constructed by the new Austrian tunneling method (NATM) with similar parameters based on type of their soil. The surface settlement was measured, and the acquired results were compared to the predicted values. The results disclosed that computing intelligence is a good substitute for numerical modeling.

Keywords: settlement, Subway Line, FLAC3D, ANFIS Method

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Authors: Golamhassan Ghahramani Aghdam, Pedram Bavili Tabrizi

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The aim of this research is to investigate the relationship between accounting information and the value of the companies accepted in Tehran Exchange Market. The dependent variable in this research is the value of a company that is measured by price coefficients, and the independent variables are balance sheet information, profit and loss information, cash flow state information, and profit quality characteristics. The profit quality characteristic index is to be related and to be on-time. This research is an application research, and the research population includes all companies that are active in Tehran exchange market. The number of 194 companies was selected by the systematic method as the statistics sample in the period of 2018-2019. The multi-variable linear regression model was used for the hypotheses test. The results show that there is no relationship between accounting information and companies’ value (stock value) that can be due to the lack of efficiency of the investment market and the inability to use the accounting information by investment market activists.

Keywords: accounting information, company value, profit quality characteristics, price coefficient

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Authors: Zahra Rakhshan Masoudi, Sona Rostampour Yasouri

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Considering that the only way to save the lives of patients and healthy people who have suffered sudden accidents is blood transfusion, what is important is the presence of the known HCV virus as the most important cause of the disease after blood transfusion. HCV is one of the major global problems, and its transmission through blood causes life-threatening complications and extensive legal, social and economic consequences. On the one hand, unfortunately, there is still no effective vaccine available to prevent HCV. In Iran, the exact statistics of the prevalence of this disease have not yet been fully announced. The main purpose of this study is to investigate the prevalence rate and rapid diagnosis of HCV among those who refer to laboratory centers in Tehran. From spring to winter of 1401 (2022-2023), 2166 blood samples were collected from laboratory centers in Tehran. Blood samples were evaluated for the presence of HCV by Electrochemiluminescence (ECL) and PCR techniques along with specific HCV primers. In general, 36 samples (1.6%) were tested positive by the mentioned techniques. The results indicated that the ECL technique is a sensitive and specific diagnostic method for detecting HCV in the early stages of the disease and can be very helpful and provide the possibility of starting the treatment steps to prevent the exacerbation of the disease earlier. Also, the results of PCR technique showed that PCR is an accurate, sensitive and fast method for definitive diagnosis of HCV. It seems that the incidence rate of this disease is increasing in Iran, and investigating the spread of the disease throughout Iran for a longer period of time in the continuation of our research can be helpful in the future to take the necessary measures to prevent the transmission of the disease to people and the rapid onset Treatment steps for patients with HCV should be carried out.

Keywords: electrochemiluminescence, HCV, PCR, prevalence

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Authors: Katayoun Bagheri, Farzad Berahmandpour

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Several studies about food habits in diverse population show, early living years play significant role in building of current food habits. Suitable nutrition in children is also influenced by parent’s food habits. The aim of study is to survey the role of parent’s food habits to form of nutrition behaviours in children under 7 years in Tehran - Iran. The study is a Descriptive study. The participants were 19 children under 7 years with their mothers from a kindergarten in the central Tehran. The sampling method was random sampling. The data was collected by food habits questionnaires and implementation of consultation meetings with the mothers. The data analysis was qualitative analysis. The findings show that 79% children and their parents have eaten enough and variety breakfast, but food choices of children were depended on food choices of parents. In the other meals, the majority of children enjoyed to eat dinner (58%), because the more families could eat dinner together. According to mother opinions, the children enjoy eating macaroni, chicken, fried potatoes, chips and fruit juices. The researchers argue that mother’s role is unavoidable in the food preferences among children. Fortunately, the results believe that children tend to drink simple milk (79%). Moreover, their parents lead them to chocolate milk consumption (42%) instead of other flavored milk. Finally, despite popular belief claim that mothers influence on nutrition behavior of children, but the study argues that the fathers have more effects on children’s nutrition behaviours. In conclusion, it seems that the general trainings about promoting healthy nutrition behavior for parents by mass media can improve nutrition habits and behaviours of pre school children.

Keywords: food habits, parents, nutrition behaviours, children, promoting nutrition

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Authors: João Coutinho-Rodrigues, Nuno Sousa, Luís Alçada-Almeida

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Transportation infrastructure systems are fundamental in modern society and economy. However, they need modernizing, maintaining, and reinforcing interventions which require large investments. In many countries, accumulated intervention delays arise from aging and intense use, being magnified by financial constraints of the past. The decision problem of managing the renewal of large backlogs is common to several types of important transportation infrastructures (e.g., railways, roads). This problem requires considering financial aspects as well as operational constraints under a multidimensional framework. The present research introduces a linear programming multiobjective model for managing railway infrastructure asset renewal. The model aims at minimizing three objectives: (i) yearly investment peak, by evenly spreading investment throughout multiple years; (ii) total cost, which includes extra maintenance costs incurred from renewal backlogs; (iii) priority delays related to work start postponements on the higher priority railway sections. Operational constraints ensure that passenger and freight services are not excessively delayed from having railway line sections under intervention. Achieving a balanced annual investment plan, without compromising the total financial effort or excessively postponing the execution of the priority works, was the motivation for pursuing the research which is now presented. The methodology, inspired by a real case study and tested with real data, reflects aspects of the practice of an infrastructure management company and is generalizable to different types of infrastructure (e.g., railways, highways). It was conceived for treating renewal interventions in infrastructure assets, which is a railway network may be rails, ballasts, sleepers, etc.; while a section is under intervention, trains must run at reduced speed, causing delays in services. The model cannot, therefore, allow for an accumulation of works on the same line, which may cause excessively large delays. Similarly, the lines do not all have the same socio-economic importance or service intensity, making it is necessary to prioritize the sections to be renewed. The model takes these issues into account, and its output is an optimized works schedule for the renewal project translatable in Gantt charts The infrastructure management company provided all the data for the first test case study and validated the parameterization. This case consists of several sections to be renewed, over 5 years and belonging to 17 lines. A large instance was also generated, reflecting a problem of a size similar to the USA railway network (considered the largest one in the world), so it is not expected that considerably larger problems appear in real life; an average of 25 years backlog and ten years of project horizon was considered. Despite the very large increase in the number of decision variables (200 times as large), the computational time cost did not increase very significantly. It is thus expectable that just about any real-life problem can be treated in a modern computer, regardless of size. The trade-off analysis shows that if the decision maker allows some increase in max yearly investment (i.e., degradation of objective ii), solutions improve considerably in the remaining two objectives.

Keywords: transport infrastructure, asset renewal, railway maintenance, multiobjective modeling

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Authors: Gerardo Casal, Miguel E. Vázquez-Méndez

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The clothoid (also known as Cornu spiral or Euler spiral) is a curve that is characterized because its curvature is proportional to its length. This property makes that it would be widely used as transition curve for designing the layout of roads and railway tracks. In this work, from the geometrical property characterizing the clothoid, its parametric equations are obtained and two algorithms to compute it are compared. The first (classical), is widely used in Surveying Schools and it is based on the use of explicit formulas obtained from Taylor expansions of sine and cosine functions. The second one (alternative) is a very simple algorithm, based on the numerical solution of the initial value problems giving the clothoid parameterization. Both methods are compared in some typical surveying problems. The alternative method does not use complex formulas and so it is conceptually very simple and easy to apply. It gives good results, even if the classical method goes wrong (if the quotient between length and radius of curvature is high), needs no subsequent translations nor rotations and, consequently, it seems an efficient tool for designing the layout of roads and railway tracks.

Keywords: transition curves, railroad and highway engineering, Runge-Kutta methods

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Authors: Muskaan Sethi, Arnab Banerjee, Bappaditya Manna

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The present paper aims to investigate a suitable contact between a wheel rolling over a flexible beam. A Linear Complementary (LCP) based approach has been adopted to simulate the contact dynamics for a rigid wheel traversing over a flexible Euler Bernoulli simply supported beam. The adopted methodology is suitable to incorporate the effect of frictional force acting at the wheel-beam interface. Moreover, the possibility of the generation of a gap between the two bodies has also been considered. The present method is based on a unilateral contact assumption which assumes that no penetration would occur when the two bodies come in contact. This assumption helps to predict the contact between wheels and beams in a more practical sense. The proposed methodology is validated with the previously published results and is found to be in good agreement. Further, this method is applied to simulate the contact between wheels and beams for various railway configurations. Moreover, different parametric studies are conducted to study the contact dynamics between the wheel and beam more thoroughly.

Keywords: contact dynamics, linear complementary problem, railway dynamics, unilateral contact

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Authors: O. Lopez, F. Pedro, A. Tadeu, J. Antonio, A. Coelho

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The future of the railway industry lies in the innovation of lighter, more efficient and more sustainable trains. Weight optimizations in railway vehicles allow reducing power consumption and CO₂ emissions, increasing the efficiency of the engines and the maximum speed reached. Additionally, they reduce wear of wheels and rails, increase the space available for passengers, etc. Among the various systems that integrate railway interiors, the flooring system is one which has greater impact both on passenger safety and comfort, as well as on the weight of the interior systems. Due to the high weight saving potential, relative high mechanical resistance, good acoustic and thermal performance, ease of modular design, cost-effectiveness and long life, the use of new sustainable composite materials and panels provide the latest innovations for competitive solutions in the development of flooring systems. However, one of the main drawbacks of the flooring systems is their relatively poor resistance to point loads. Point loads in railway interiors can be caused by passengers or by components fixed to the flooring system, such as seats and restraint systems, handrails, etc. In this way, they can originate higher fatigue solicitations under service loads or zones with high stress concentrations under exceptional loads (higher longitudinal, transverse and vertical accelerations), thus reducing its useful life. Therefore, to verify all the mechanical and functional requirements of the flooring systems, many physical prototypes would be created during the design phase, with all of the high costs associated with it. Nowadays, the use of virtual prototyping methods by computer-aided design (CAD) and computer-aided engineering (CAE) softwares allow validating a product before committing to making physical test prototypes. The scope of this work was to current computer tools and integrate the processes of innovation, development, and manufacturing to reduce the time from design to finished product and optimise the development of the product for higher levels of performance and reliability. In this case, the mechanical response of several sandwich panels with different cores, polystyrene foams, and composite corks, were assessed, to optimise the weight and the mechanical performance of a flooring solution for railways. Sandwich panels with aluminum face sheets were tested to characterise its mechanical performance and determine the polystyrene foam and cork properties when used as inner cores. Then, a railway flooring solution was fully modelled (including the elastomer pads to provide the required vibration isolation from the car body) and perform structural simulations using FEM analysis to comply all the technical product specifications for the supply of a flooring system. Zones with high stress concentrations are studied and tested. The influence of vibration modes on the comfort level and stability is discussed. The information obtained with the computer tools was then completed with several mechanical tests performed on some solutions, and on specific components. The results of the numerical simulations and experimental campaign carried out are presented in this paper. This research work was performed as part of the POCI-01-0247-FEDER-003474 (coMMUTe) Project funded by Portugal 2020 through COMPETE 2020.

Keywords: cork agglomerate core, mechanical performance, numerical simulation, railway flooring system

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Authors: Cuong D. Dao, Rob J.I. Basten, Andreas Hartmann

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This paper studies the optimal maintenance planning of preventive maintenance and renewal activities for components in a single railway track when the available time for maintenance is limited. The rail-track system consists of several types of components, such as rail, ballast, and switches with different preventive maintenance and renewal intervals. To perform maintenance or renewal on the track, a train free period for maintenance, called a possession, is required. Since a major possession directly affects the regular train schedule, maintenance and renewal activities are clustered as much as possible. In a highly dense and utilized railway network, the possession time on the track is critical since the demand for train operations is very high and a long possession has a severe impact on the regular train schedule. We present an optimization model and investigate the maintenance schedules with and without the possession capacity constraint. In addition, we also integrate the social-economic cost related to the effects of the maintenance time to the variable possession cost into the optimization model. A numerical example is provided to illustrate the model.

Keywords: rail-track components, maintenance, optimal clustering, possession capacity

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Authors: Mohammad Javad Afroughi, Vahid Hosseini, Jason S. Olfert

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Both traffic-generated particles and noise have been associated with the development of cardiovascular diseases, especially in near-highway environments. Although noise and particulate matters (PM) have different mechanisms of dispersion, sharing the same emission source in urban areas (road traffics) can result in a similar degree of variability in their levels. This study investigated the temporal variation of and correlation between noise levels, PM concentrations and traffic intensities near a major highway in Tehran, Iran. Tehran particulate concentration is highly influenced by road traffic. Additionally, Tehran ultrafine particles (UFP, PM<0.1 µm) are mostly emitted from combustion processes of motor vehicles. This gives a high possibility of a strong association between traffic-related noise and UFP in near-highway environments of this megacity. Hourly average of equivalent continuous sound pressure level (Leq), total number concentration of UFPs, mass concentration of PM2.5 and PM10, as well as traffic count and speed were simultaneously measured over a period of three days in winter. Additionally, meteorological data including temperature, relative humidity, wind speed and direction were collected in a weather station, located 3 km from the monitoring site. Noise levels showed relatively low temporal variability in near-highway environments compared to PM concentrations. Hourly average of Leq ranged from 63.8 to 69.9 dB(A) (mean ~ 68 dB(A)), while hourly concentration of particles varied from 30,800 to 108,800 cm-3 for UFP (mean ~ 64,500 cm-3), 41 to 75 µg m-3 for PM2.5 (mean ~ 53 µg m-3), and 62 to 112 µg m-3 for PM10 (mean ~ 88 µg m-3). The Pearson correlation coefficient revealed strong relationship between noise and UFP (r ~ 0.61) overall. Under downwind conditions, UFP number concentration showed the strongest association with noise level (r ~ 0.63). The coefficient decreased to a lesser degree under upwind conditions (r ~ 0.24) due to the significant role of wind and humidity in UFP dynamics. Furthermore, PM2.5 and PM10 correlated moderately with noise (r ~ 0.52 and 0.44 respectively). In general, traffic counts were more strongly associated with noise and PM compared to traffic speeds. It was concluded that noise level combined with meteorological data can be used as a proxy to estimate PM concentrations (specifically UFP number concentration) in near-highway environments of Tehran. However, it is important to measure joint variability of noise and particles to study their health effects in epidemiological studies.

Keywords: noise, particulate matter, PM10, PM2.5, ultrafine particle

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Authors: Farideh Gheitasi, Amir Hossain Jaberansari, Payam Abedini

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The World Health Organization (WHO) Manifesto for Safe Communities states that "All human beings have an equal right to health and safety". The purpose of a safe Community is to minimize the damages threatening people. It seems that not sufficient attention has been given to relate environment and objectives of the safe Community. The reason for that can be assigned to the lack of enough information about environmental parameters and their relation with indices of the safe community like type and effect time of damages resulting from air pollution. Air pollution can be characterized as one of main environmental problems of Tehran. This problem is mostly due to the special geographic and climate situation, high population density and irregular growth in the number of vehicles. This paper is aimed at investigating the necessity of considering environmental factors to obtain a safe community through determining the effects of environmental pollution, particularly air pollution, on 490000 elders (+65) of Tehran. The methodology used in this study was on the basis of Random sampling and social surveying. The number of questionnaires was determined to be 321 through using Cochran method and the questionnaires were filled out by elders during personal interviews. The analysis of obtained results indicated that elders believe the major effects of air pollution include heart and respiratory diseases, obligation to stay at home on polluted days and its associated mental problems. Moreover, it was found that there is direct link between the number of polluted days and mortality frequency of elders. Having an environmental view may have an appreciable influence on the qualitative and quantitative development of activities and also facilitate obtaining the goals of the Safe Communities. In addition to reduce damages caused by pollutions, this view will encourage friends of the environment to cooperate with authorities of the safe community.

Keywords: air pollution, elderly people, environment, waste management

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