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The Selection of a Possible Organizational Structure of Railway Companies by Application Fuzzy-ARAS Method
Get PDFThe European railway sector doesn\u27t represent a single, generic type of organizational structure. The Directives from the 1990s offer the possibility for national interpretation giving a wide range of organizational structures for European railways. Different organizational structures of railways are present in the European railway market, and all of them are aligned with the national belief of the country - how to manage the railway. This paper focuses on Multi-Criteria Decision Making (MCDM) methods for ranking and selecting organizational structures of railways. In decision-making, we deal with different types of uncertainty and inaccuracy. For this purpose, we need to use some specific tools. In this paper, we use triangular fuzzy numbers to quantify linguistic data. To overcome the complexity of the decision-making problem, we propose the fuzzy Additive Ratio ASsessment (ARAS) method, which also includes linguistic variables and a group approach to decision-making. With the proposed methodology an evaluation of the alternatives to the organization structure of the railway company in Bosnia and Herzegovina is considered. Separation of railway transport from infrastructure management is ranked as the best organizational structure for this company
Impact of Road Pavement Condition on Vehicular Free Flow Speed, Vibration and In-Vehicle Noise
Get PDFRoad infrastructure in good condition is a key requirement for efficient transportation systems which leads to economic prosperity and improved quality of life. However, road surface conditions deteriorate over time according to traffic loads and environmental factors. Poor road conditions lead to congestion, accidents, lost productivity, and driver fatigue. This work considers the relationship between road pavement condition and vehicle speed, vibration, and in-vehicle noise. A 7 km section of the Grand Trunk Road, Peshawar, Pakistan divided into 280 segments (140 for each lane), of length 50 m was observed and the Pavement Condition Index (PCI) of each segment was determined based on the recurrent distress type and density according to ASTM D6433-011 guidelines. The number of very good, satisfactory, fair, poor, and very poor conditions are 51, 52, 81, 48, and 42, respectively. The mobile app BotlnckDectr was employed to measure vehicle speed, RPM, noise, vibration, GPS location, and time. Statistical analysis was employed to determine the relationship between PCI and vehicle speed, vibration, and in-vehicle noise. The results obtained indicate that noise and vibration increase by 3.3% and more than 30%, respectively, as the pavement condition changes from good to very poor, and vehicle speed decreases by 8.8%
Electro-Osmotic Blood Flow of Shear-Thinning Fluid with Hall Current and Wall Flexibility
Get PDFThe presented article aims to present the flow of blood in microchannels such as veins and arteries via peristaltic flow. The magnetic field is imposed to regulate the flow as laminar. Also, its impacts in terms of Hall current have been considered. The rate of heat transfer is further based on Joule heating and viscous dissipation aspects. Mathematical analysis has been conducted given long wavelength and small Reynolds number. Such preferences are relatable to the medical domain where the magnetic field regulates the flow stream and aids in the melting of blood clots in patients with various heart diseases. The solution for electric potential is calculated analytically while the velocity, temperature, and heat transfer rate are executed directly via the built-in command of Mathematica software. Since the magnetic field acts as an opposing force. Results show that the velocity and temperature are decreasing functions of the magnetic field. However, the temperature is increasing for Weissenberg number
The Effect of Nozzle Size on the Tensile and Flexural Properties of PLA Parts Fabricated Via FDM
Get PDFThe nozzle of a 3D printer extrudes molten filament onto the print surface. The detachable and adjustable nozzle of a 3D printer allows for the printing of lines of varying thickness. This study intends to investigate the effect of nozzle diameter on the tensile and flexural properties of printed specimens. The tensile and flexural specimens were prepared according to ASTM D638 Type 1 and ISO 178, respectively. After specimens were printed with nozzles having diameters of 0.3, 0.4, 0.5, 0.6, and 0.8 mm, tensile and flexural tests were conducted using an Instron 5585 machine. Each specimen was printed with 0.2 mm layer thickness, a line pattern, and 100 percent infill. Tensile and flexural behaviors of PLA specimens were comparable, according to the findings. Tensile and flexural strengths increase as nozzle diameter increases, but they are only effective up to a certain diameter. At a nozzle diameter of 0.6 mm, the maximum tensile strength was 33.32 MPa, and at a nozzle diameter of 0.5 mm, the maximum flexural strength was 76.76 MPa. The flexural strength decreases when using nozzles with diameters of 0.6 and 0.8 mm, and the tensile strength decreases when using a nozzle with a larger diameter (0.8 mm). Because the diameter of the nozzle has a significant impact on the mechanical properties of a part, it is crucial to choose the correct nozzle diameter for optimal mechanical properties
Analytical and Numerical Contact Stress Analysis of Spur Gears
Get PDFThe damage that occurs on the teeth flank of cylindrical gears is a complex phenomenon and depends on many factors. The most common cause for these damages is the high contact stress of the meshing gears. Although this contact pressure, by itself, cannot be a criterion for determining the durability of the gears, a good correlation has been found between the contact or Hertz pressure and the damage that occurs on the tooth flank. This paper analyzes the influence of the pressure angle α on the contact stress. Analytical calculation according to the ISO 6336-2:2006 and finite element method (FEM) was used for the analysis. Four cases were analyzed with a change in the pressure angle, i.e., cylindrical spur gears and pressure angles of 17.5°, 20°, 22.5° and 25°. In the results, it was noted that by increasing the pressure angle, the contact stress decreases. It can also be concluded that by increasing the pressure angle, the difference in the results between the analytical and FEM analysis, also increases
Transient Analysis of Thermal Bending and Vibration of Steam Turbine Rotor
Get PDFRotor-bearing systems often exhibit nonlinear behavior due to hydrodynamic effects and external forces. Finite element methods based on linear analysis are commonly used for rotor dynamic analyses, where nonlinear bearing/damping forces are linearized into equivalent stiffness and damping coefficients. However, this method may not accurately describe strongly nonlinear systems. Engineers use transient analysis and nonlinear models to improve rotor behavior analysis. This study investigates the effects of transient-thermal bending and vibration on a high-pressure steam turbine rotor using the finite element method. A scaled rotor-shaft was used to study thermal bending and vibrations caused by steam heat. The design of the shaft was based on an existing power station high-pressure turbine rotor. Numerical modal analyses were performed using ANSYS software to obtain a partial level of integrity between the numerical model and the analytical model. Natural frequencies were compared between the experimental, numerical, and analytical results, which showed good correlations
Prediction of User Throughput in the Mobile Network Along the Motorway and Trunk Road
Get PDFThe main goal of this research is to create a machine learning model for predicting user throughput in the mobile 4G network of the network provider M:tel Banja Luka, Bosnia and Herzegovina. The geographical area of the research is limited to the section of Motorway "9th January" (M9J) Banja Luka - Doboj, between the node Johovac and the town of Prnjavor (P-J section), and the area of the section of trunk road M17, between the node Johovac and the town of Doboj (J-D section). Based on the set of collected data, several models based on machine learning techniques were trained and tested together with the application of the Correlation-based Feature Selection (CFS) method to reduce the space of input variables. The test results showed that the models based on k-Nearest Neighbors (k-NN) have the lowest relative prediction error, for both sections, while the model created for the trunk road section has significantly better performance
Modelling of Pollutants Dispersion from Open Burning of Solid Waste Using AERMOD
Get PDFThis study evaluates the air quality impact of open burning of solid waste activities in Ilorin, Nigeria. An emission inventory was carried out to quantify the emitted CO, NOx and SOx from 2016- 2020 into the study area. Their ground level concentrations were computed with the Industrial Source Complex – American Meteorological Society (AMS) and United State Environmental Protection Agency (EPA) Regulatory Model (AERMOD) dispersion model and compared with standards to determine their impacts on ambient air quality. The average hourly, daily and annual concentrations were 25,267 µg/m3, 4,609 µg/m3, 447 µg/m3 for carbon monoxide (CO); 4,700 µg/m3, 730 µg/m3, 130 µg/m3 for oxides of nitrogen (NOx) and 954 µg/m3, 144 µg/m3, 24 µg/m3 for oxides of sulphur (SOx) respectively. The hourly air quality for CO were within the World Bank standard for all the receptor communities except at Abe-Emi with 2.17 folds, while the daily air quality was within the Federal Ministry of Environment (FMEnV) limit. However, the 1-h, 24-h and annual air quality for NOx exceeded the FMEnV and World Bank standard for all the receptor communities. Similarly, the hourly and daily air quality for SOx exceeded the FMEnV and World Bank standard for all the receptor communities
Key Evaluation Criteria for Assessing the Introduction of Electric Vehicles into the Logistics Operators Fleet
Get PDFIncreasing demands for logistics services cause several challenges related to total costs and meeting global environmental requirements. Logistic operators make efforts to improve all logistic processes and the distribution chain system by optimizing distribution networks and transport routes. Also, using clean or renewable energy help to meet the above-mentioned requirements by using environmentally friendly means of transportation such as electric and hybrid vehicles. The replacement of conventional with electric vehicles provides numerous benefits for improving the efficiency of the distribution chain system. This process is part of the concept known as Green Logistics, which strives to minimize the environmental impact of the logistics network and delivery. This paper focuses on identification of indicators for evaluating the acceptability of replacing conventional vehicles with electric vehicles in the fleet of logistics operators. We propose an evaluation matrix based on key indicators such as total costs, eco score fleet rating, and range and energy supply of vehicles. We use these indicators to determine the advantages, challenges, and possibilities of introducing electric vehicles in the logistics operator’s fleet. Also, we conducted a multi-criteria analysis of replacing conventional with electric vehicles in the fleet of one logistics operator
Modeling and simulation of fiber optic transmission links
Get PDFThe main aim of the paper is modeling and simulation of fiber optic transmission. It also deals with ways to increase the capacity of fiber optic transmission links by using WDM (Wavelength Division Multiplexing) system. The parameters of the fiber optic transmission link were measured on a real optical transmission links and a model for simulation was set up. A simulation of increasing the capacity of a fiber optic transmission link was made in two ways. The first one is to increase the transmission speeds of the individual channels of the WDM system, and the second one is to increase the number of WDM system channels with lower individual speeds. The simulation results showed that the second method provides better quality of WDM service. The additional experiment was done on an existing ITU T G.655 optical fiber intended for WDM systems whose parameters were measured. Bit error rate and Q parameter for WDM system of 4 and 16 channel was used to check quality of proposed solution