The modeling of effective parameters on public bus passengers’ boarding time prediction

Passengers’ boarding times at bus stops have a great importance to calculate dwell and travel time for scheduling process in public transport operations. However, there are not so much observed boarding times data in the actual bus transport systems and it may cause some prediction problems in scheduling process of public transport operations. For this reason, accurate estimation of the boarding times will ensure correct calculation of dwell and total travel time for bus transport systems. Based on this idea, this study aims to model boarding times of each passengers by evaluating different parameters using two different (statistical and optimization analysis) methods. For this purpose, a comprehensive data collection process was conducted in total seven different cities of Turkey based upon their population. Two new models were developed for boarding time estimation by evaluating various parameters using a multiple Ordinary Least Square (OLS) regression and Artificial Bee Colony (ABC) algorithm as statistical and optimization methods, respectively. Study results showed that modeling of boarding times by considering various parameters is an effective strategy to improve the performance of bus transport systems by using developed two models

Intracardiac Mass Detection and Classification Using Double Convolutional Neural Network Classifier

Intracardiac masses identification in the images of echocardiogram images in one of the most essential tasks in making the diagnosis of cardiac disease. For making the improvement in accuracy over the diagnosis as a new complete method of classifying the echocardiogram images automatically which is based on robust back propagation neural network algorithm in being proposed for distinguishing intracardiac thrombi and tumor. Initially, the cropping over the specific region is done in order to make the definition of the mass area. Later on, as the second step the processing of globally unique denoising technique is being implied for the removal of speckle and in order to make the preservation of anatomical structured component in the image. This is defined in terms of preprocessing and it is carried out by Patch-based sparse representation. Subsequently the description of the mass contour and its interconnected wall of the artery are being done by the segmentation mechanism denoted as Linear Iterative Vessel Segmentation model. As the prefinal stage, the processing of boundary, texture and the motion features are being carried out through the processing by double convolutional neural network (DCNN) classifier in order to determine the classification of two different masses. Totally 108 cardiac masses images are being collected for accessing the effectiveness of the classifier. It is also realized with the various state of the art classifiers as projected the demonstration of the greatest performance that has been disclosed with an achievement of 98.98% of accuracy, 98.89% of sensitivity and 99.16% of specificity that has been resulted for DCNN classifier. It determines the explication that the proposed method is capable of performing the classification of intracardiac thrombi and tumors in the echocardiography and ensures for potentially assisting the medical doctors who are in the clinical practice.

Effect of Curing Temperature on the Mechanical Strength of Alkali Activated Laterite Geopolymeric Samples

A huge amount of carbon dioxide is released in the Portland cement production process. A large quantity of greenhouse gases is produced because of the significant amount of energy consumption via making bricks through firing. Using the pozzolanic sources containing the aluminosilicate and alkaline reagents, a new type of green materials called geopolymeric materials are produced with quite lower environmental hazards. The use of laterite as an iron-rich aluminosilicate material has a high potential for building materials. In this study, the effect of the curing temperature and characteristics of the alkaline reagent including the concentration of sodium hydroxide solution and the water-glass to sodium hydroxide mass mixing ratio on the mechanical strength of the laterite-based, oven-cured geopolymer samples was investigated. The results showed that the curing temperature had a significant effect on the compressive strength of the laterite-based geopolymer samples so that with a 15°C change at the curing temperature, the compressive strength of the samples could be multiplied and a sharp increase in the mechanical strength could occur. Also, according to the results of this study, the 6 M sodium hydroxide is recommended for the construction of the laterite-based geopolymer materials with low cost and relatively high strength, and for the construction of higher-strength building materials, the 14 M sodium hydroxide is recommended.

Energy dissipation performance of the trapezoidal stepped spillway

Stepped spillways are a more effective type of spillway in energy dissipation than conventional chute channels. Therefore, the dimensions of the energy breaker at the downstream of the stepped spillways are lower. It is an alternative especially for the downstream pool that cannot be built in sufficient length due to the terrain conditions. In this study, the energy dissipation performance of the trapezoidal stepped spillways was investigated numerically by using Flow3D software. Four different models and three different discharges were utilized for this aim. According to the results, the trapezoidal stepped spillway is more effective up to 30% than classical stepped spillways in energy dissipation. The depth of the trapezoidal step and the bottom base length of the trapezoid significantly affected the energy dissipation rate for the trapezoidal stepped spillway.

Independent Active and Reactive Power Control for Single Stage H8 Transformer-less Solar PV Inverter

With the rapid development in power electronics technologies and solar photovoltaic (PV) cells, the interest in solar PV cell-based electric power generation and other applications is increasing more incredibly. For low power grid or direct load applications, single-stage solar PV inverters without transformers are advantageous. Based on this concept solar single-stage eight switch H8 based transformerless solar PV inverter is proposed. The objective of the work is to present a control scheme for the H8 inverter to have better power handling capability and for independent active and reactive power control. For this, the test system is studied using MATLAB/ SIMULINK software under three cases (i) constant active power and varying reactive power, (ii) varying active power and constant reactive power, and (iii) varying both active and reactive power. The proposed inverter is compared with single-stage solar PV with two switches boost and six switches inverter topology. It is found that power flow ripples and surges are lesser for proposed H8 than with single-stage topology.

Investigation of Deformation-Based Damage Limits of RC Columns for Different Seismic Codes

The seismic performance of reinforced-concrete columns is related to the expected damage limits under seismic loads and how this damage relates to safety of the structure. In order to assess the performance of reinforced-concrete columns under seismic loads, performance-based deformation and damage limits are proposed by the seismic codes. Adequacy of the deformation and damage limit levels given in the codes such as Seismic Evaluation and Retrofit of Existing Buildings Standard, ASCE/SEI-41 (2017) and Turkish Building Earthquake Code (2018) were evaluated by carrying out parametric studies for RC columns. Reinforced-concrete circular columns are designed in parametric studies to present the effects of various parameters such as concrete compressive strength, axial load levels and spiral reinforcement ratio on performance-based damage limits. Performance limits corresponding to each performance levels obtained by different seismic guidelines were compared. When the results obtained from the analyzes are examined, it has been observed that there are significantly different results in the cross-section damage limits values of ASCE/SEI-41 (2017) and TBEC (2018) regulation, which can change the performance level of the building. TBEC (2018) gives approximately 50% conservative limitations when they are compared with the ASCE/SEI-41 (2017) limitations. As a result, TBDY (2018) seems to offer safer and ductile solutions than ASCE ASCE/SEI-41 (2017).

An experimental investigation of viscosity of a newly developed natural polymer-based media for abrasive flow machining (AFM) of 3D printed ABS parts

Abrasive Flow Machining (AFM) is the method of finishing complex surfaces and internal channels with the help of extrusion pressure and abrasive-laden viscoelastic polymer media. This paper is based on developing a new AFM media using a natural waste polymer as a base material. In the article, a natural polymer media viz. rice husk ash-based media has been developed, and subsequently, rheological analysis has been done, and experimentation has been performed on Anton-paar® rheometer to optimize the viscosity of these newly developed AFM media. In this research study, the hollow elliptical shape of ABS (acrylonitrile-butadiene-styrene) material was manufactured using the FDM technique and then finished with a one-way AFM machine. This paper examined the parametric dependencies of AFM process parameters on finishing FDM printed hollow elliptical parts. The improved surface roughness of the FDM printed hollow elliptical parts has been investigated relating to the AFM process parameters. The maximum surface roughness has been achieved by 95.98%.

Earth fault detection in distributed power systems on the basis of artificial neural networks approach

Nowadays, the advancement of microgrids promises numerous economic and environmental advantages of renewable energies to nations and societies. The presence of decentralized energy units, however, makes serious technical challenges; for instance, criteria and procedure of fault recognition and diagnosis in this condition is entirely changing. This article, therefore, proposed a novel accurate and fast technique based on Artificial Neural Networks (ANN) for earth fault detection. A sample distributed power system considered for the proposed technique and different earth faults applied to this system consist of one phase, two phases and three phases faults. Also, any alteration of current and voltage signals of all phases is investigated at the fault occurrence moment. Analysis of simulation results demonstrates how the proposed technique could make faster responses and improve the reliability of the distributed power system by more accurate fault recognition in comparison with the other traditional methods such as the Wavelet Transformation technique. The proposed technique is likely to enhance the growth of renewable energy sources usage by decreasing operational risk factors and fault recognition delays.

Effect of Saw Type Corrugated Pipe on Laminar Convective Heat Transfer by Using SiC-Water Nanofluid: A Numerical Study

Enhancing the heat transfer rate is highly required to remove excessive heat load from the heat transfer apparatus, which may cause massive damage to the equipment. Thus, increment of heat transfer area is one of the prime solutions for this issue. The increment of heat transfer area can be done by enhancing the pipe wall and incorporating nanoparticles with working fluids because nanoparticles showed much faster heat dispersion due to a vast surface area for heat transfer and increased thermal conductivity. Also, small molecules of nanoparticles are allowed for free movement and thus micro-convection, promoting high thermal conductivity. Higher thermal conductivity is mainly the result of a higher heat transfer rate. Therefore, in this study, a saw-type corrugated tube was considered along with the SiC-water nanofluid as the working fluid to determine the improvement of laminar convective heat transfer in terms of the Nusselt number, heat transfer coefficient, and pressure loss. The result demonstrated that by increasing the Reynolds number, the Nusselt number, heat transfer coefficient, and pressure loss were increased significantly with the enhancement of SiC-water concentration. At a Reynolds number of 1200, the maximum increment of Nusselt number in comparison to the base fluid was 9.15% when the corrugated pipe was considered. Meanwhile, the maximum improvement of heat transfer coefficient for SiC-water nanofluid in comparison to the base fluid was 37.66%.

CFD Simulation of Helical Shell and Tube Heat Exchanger Using Optimization Techniques

The objective of this study is to simulate the performance of helical tube shell and tube heat exchanger with several optimization techniques using computational fluid dynamics CFD. To check the performance of a designed model of heat exchanger various techniques are available. In this study, the various possible model of the heat exchanger to enhance the performance of the device have been designed. Firstly, the straight tube is replaced by helical tube in the heat exchanger and used 10, 12, 14 number of helical baffles with 50% baffle cut. Total ten models have been developed. These models are model-I 4-turns without baffle, model-II 4-turns with 10 number baffles, model-III 5-turns without baffle, model-IV 5-turns with 12 number baffles, model-V 6-turns without baffle, model-VI 6-turns with 10 number baffles 0.083m baffle space, model-VII 6-turns with 12 number 0.083m baffle space, model-VIII 6-turns with 14 number baffles 0.064m baffle space, model-IX 7-turns without baffle, model-X 7-turns with 14 number baffles, different number of baffles and baffle space with 50% baffle cut and used CUO nanofluid model-XI 6-turns with 14 number baffle CUO fluid 0.083m baffle space CFD analysis simulation done on ANSYS FLUENT 18. The simulated result shows that the model XI is approximately 40% more optimized as compared to model-I and approximately 24% than model-VIII. It also found that the high heat transfer obtains with increased number of baffles.