JECET : Journal of Environmental Science, Computer Science and Engineering & Technology. E-ISSN : 2278-179X

      JECET : Journal of Environmental Science, Computer Science and Engineering & Technology

Research Papers in Eng Science

Footwear Industry in Bangladesh: Reduction of Lead time by using Lean Tools

Md. Abu Sayid Mia, Md. Nur-E-Alam, Md. Lutfor Rahman and M. Kamal Uddin,[DOI: https://doi.org/10.24214/jecet.C.6.3.25159]

The footwear industry is a booming and one of the largest manufacturing sectors in Bangladesh. This study was carried out in a leading footwear manufacturing industry in Bangladesh for the court shoe production line. The main target of this study was to reduce the lead time by using lean tools like Value Stream Mapping (VSM), Process Cycle Efficiency (PCE) and Pareto Analysis. Lean manufacturing is a systematic approach to identifying and eliminating wastes (non-value-added activities) through continuous improvement by conveying the product at the pull of the customer in pursuit of production. At present state, lead time, PCE and takt time of court shoe production were observed gradually 83867 sec, 8.32%, and 26.73 sec/pair. Ultimately, after the implementation of lean tools, at future state, the lead time, PCE and takt time of this production line 35866 sec, 19.46% and 15.26 sec/pair respectively.

Monthly Average Forecasting of Wind Speed Using Time Series Models

Dokur E., Ceyhan S., Kurban M.

Wind speed modeling and prediction plays a critical role in wind related engineering studies. With the integration of wind energy into electricity grids, it is becoming increasingly important to obtain accurate wind speed forecasts. Accurate wind speed forecasts are necessary to schedule dispatch able generation and tariffs in the electricity market. The aim of this paper is to develop the most suitable models for monthly average forecasting of wind speeds using SARIMA (Seasonal Auto-Regressive Integrated Moving Average) models with some statistical tests. SARIMA models and statistical tests are implemented in MATLAB software. All the models are analyzed with real data of wind speeds collected over a period of 11 years, Bilecik, city of Turkey. Ljung-Box and Durbin Watson tests are carried out to ideal model. Accuracy of the forecasting is evaluated in terms of RMSE, MSE, and MAPE.

Bubble Counter for Resistive Plate Chamber

Md. Manjurul Gan, Jitu Prakash Dhar, Dr. Md. Saiful IslamS.D. Kalmani, R.R. Shinde, TapanVinshi1 and P.V. Hunagund

The Resistive Plate Chamber (RPC) is an active element of INO-ICAL experiment1,2. It is a gaseous detector and hence the gas needs to be continuously flushed through it. The gas flow need to be uniform and with a proper flow rate of about 6 SCCM (Standard Cubic Centimetre per Minute). This flow rate corresponds to about one volume changes per day of gas, which is required for the good performance of the RPCs. The safety operating pressure at the input is about 4 mbar.

An open ended gas system is shown in Figure 1. The gas coming out of the RPC is left out into the atmosphere through a bubbler containing non-degassing oil DC706. The outlet of the RPC is connected to an Isolation bubbler and at the input bubbler is called as the safety bubbler. When there is a block, due to dust particle or any impurity in the RPC, the safety bubbler releases the gas into the atmosphere and thus protects the RPC. The oil levels in the two bubbler is such that, the level in the safety bubbler is double (10 mm) than, that of the isolation bubbler. When the gas flows through the RPC, bubbles are seen in the isolation bubbler and indicate that the system is functioning well, which means there is continuous flow of gas through that RPC. Therefore, counting these bubbles indicate, there is a flow of gas in the RPC and the number of bubbles count will give the quantity of gas flowing through it. To count these bubbles a microcontroller based system has been developed and successfully integrated during initial studies of Gas system and RPCs tests. The detail of electronics tool developed is presented.

Ultrasonic Ride Height Monitoring of Automobile by Cross-correlation

Md. Manjurul Gani, Jitu Prakash Dhar, Dr. Md. Saiful Islam

Ground clearance or ride height (distance between the lowest part of the vehicle and ground) is an important parameter for automobile. It varies with respect to load on the vehicle as well as road which could be rough and bumpy. Therefore scratching of vehicle with the ground or road is a common scenario. To avoid this scratching we need to monitor ground clearance. To do so we design and simulate an ultrasonic ground clearance monitoring system. Here an ultrasonic sensor is used to transmit and receive the signal (reflected pulse). Then an adaptive filter is used to de-noise the received signal. After that using cross-correlation the time of flight is determined to measure the ride height. When the ground clearance reaches the safety margin it will activate an indicator or alarm. It helps to avoid the scratching of vehicles which will reduce the maintenance and repairing cost/time.

Modeling and Simulation Analysis of Proton-Exchange Membrane based Fuel Cell System
Using MATLAB/Simulink

Nishita Mishra and Monika Vardia

Modeling of fuel cells is getting more and more important as powerful fuel cell stacks are getting available and have to be integrated into power systems. Proton exchange membrane fuel cells (PEMFCs) have aroused great interest in recent years, in particular for transportation applications. The simulation of proton-exchange membrane fuel cells (PEMFC) may work as a powerful tool in the development and widespread testing of alternative energy sources. In order to obtain an adequate PEMFC model, (which could be used in the analysis of FC generation systems), it is necessary to define the values for a specific group of modeling parameters. The simulation results are strongly affected by the choice of such modeling parameters. In order to investigate the output characteristic of a proton exchange membrane fuel cell (PEMFC) based on the electrical empirical model, a novel dynamic model of the PEMFC has been developed with MATLAB/ Simulink, which is distinct from the models that have been published previously.  In this paper, the governing equations of the transient behavior of a proton exchange membrane fuel cell are presented. They show the influence of the operating conditions and the current density on internal parameters, especially the ohmic resistance. By using a fuel cell test system of the Fuel Cell Application Centre (FAC) at Temasek Polytechnic, the transient electrical responses of PEMFC were conducted and analyzed under various operating conditions. A good match is found between simulation results and experimental data. The comprehensive results of simulation manifested that the model is effective and operational. This model will be very useful to optimize the structure design, improve the operation performance, and develop the real-time control system of PEMFC.

Nonlinear Least Squares Parameter Estimation Problem Using Levenberg-Marquardt Method

Wei Ching Kaw, Sie Long Kek, Sy Yi Sim

Least squares method, which is a statistical method with minimum sum squares of errors (SSE), is used for curve fitting and parameter estimation. In general, the Gauss-Newton (GN) and the Levenberg-Marquardt (LM) methods are the popular least squares method. In this paper, a nonlinear least squares problem and the LM method are discussed. In our study, the derivation of the LM algorithm is briefly described and the relevant necessary condition is satisfied. During the calculation procedure, the optimal solution, which is the optimal parameter estimate, is obtained once the convergence is achieved. For illustration, the related models for an exponential distribution with two unknown parameters, and for the average monthly high temperature with four unknown parameters are constructed. Their respective unknown parameters are estimated by applying the LM method. Besides, the best model selection is suggested to represent the dataset of the concentration of a blood sample. Moreover, a numerical comparison between the methods of LM and GN is carried out. By virtue of these examples studied, the results show the applicability of the LM method in solving the nonlinear least squares problem. In conclusion, the efficiency of the LM method is highly presented.

Investigation of Conductor Pipes in Offshore Fixed Platforms

Memardoost M.

Conductor pipes are used in offshore platforms for oil and gas extraction. The pipes are continued from the deck to the lower surface of the soil. The pipes are used as conductive drilling. The task of conductor pipes is protecting the drilling equipment during drilling and protecting the pipes in the production phase. In industry, the length of buried pipe conductor is not modelled so conductor pipe and soil interaction is not considered. In this study, exact modeling is done by considering the interaction of soil and conductor pipe. In this paper, the conductor pipe from the deck to the sea bed is modeled and along of the pipe is modeled in the soil. The conductor pipe and soil interaction is done by friction vertical non-linear and tip vertical springs. After modeling the conductor pipe using SACS software, situ analysis and analysis of earthquakes are done. The situ analysis results show that stresses on the exact model are less than the simple model in most cases. Also in earthquake analysis is shown that stresses on the exact model are less than the simple model in most cases. According to the results obtained in this study it can be concluded that fixed offshore platform used in this study using exact modeling instead of simple modeling is appropriate to optimize some of the members section">

Optimal MPPT and Inverter Control of Grid Connected Photovoltaic System

Arpita Jain and Monika Vardia

In recent years, the average rate of world primary power consumption has increased to about 16000GW. The amount of traditional energy such as petroleum and coal has been gradually becoming insufficient to meet these demands. Hence, renewable energies are playing a vital role in supplying the world’s current power demands. The photovoltaic power generation system using solar energy is growing to produce promising energy source. However solar power is not effectively utilized to replace the fossil fuels due to its intermittence nature. Due to temperature, radiation and load variations, the efficiency of the solar module reduces1,2. Thus, to track the maximum power from the solar array, the converter must operate in the maximum power point tracking (MPPT). In this paper a P&O method of MPPT is discussed for maximum extraction of power from the PV system. Here the boost converter is working as a MPPT and a three phase voltage source inverter (VSI) are connected to the grid. Space vector pulse width modulation (SVPWM) is proposed for generation of gating pulses for voltage source inverter 3-5.

Gravitational Time Delay Model in Jovian Radio Signal Reception

S. Mondal

In this paper contribution of Jupiter as radio pulsar is discussed under light of general relativity. Atheoretically approach to measure the relativistic delay in signal reception at any Earth based observatory due to gravitational lensing by Sun is considered here. A model has been proposed for such type of calculation along witha preliminary calculation, shows geometrical time delay of Jovian radio signal when it is grazing through the Sun for furthest separation between the Earth and the Jupiter is 0.443 ms.

Review Paper on Energy Audit for Industrial Boilers

Nishadevi N.Jadeja

A lot of work has been done in the field of energy audit, loss estimation and performance improvement of boilers. Many researchers have conducted experiments and studies to improve efficiency, to increase life of components and to reduce maintenance of boilers. Energy audit plays an important role in identifying energy conservation opportunities in the industrial sector, while they do not provide the final answer to the problem; they do help to identify these goals can be achieved by using better heat recovery techniques, maintaining proper airfuel ratio, using VSD, using various software and mathematical models, etc. Some of them are described here.


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