ARPN Journal of Engineering and Applied Sciences                         ISSN 1819-6608
 
 
 
ARPN Journal of Engineering and Applied Sciences                July 2009 | Vol.4  No.5
Title: Comparison between the measured passing discharges through long throated flume and estimated discharge by winflume software
Author (s): Samad Emamgholizadeh, Ehsan Kazemassar and Omid Masodi
Abstract:

In the flow measuring structures with control section such as Long-throated flumes and broad-crested weirs, a relationship would be produced between water depth and discharge. The long-throated flume is the new structure which proposed for flow measuring. This structure provides economical and flexible water measurement capabilities for a wide variety of open-channel flow situations. The advantages of this structure include minimal head loss, low construction cost, adaptability to a variety of channel types, and ability to measure wide ranges of flows with custom-designed structures. In order to investigate the ability of Winflume model in estimating discharge passing through long throated flume, a series of laboratory experiments were carried out in a flow measurement flume of rectangular cross section. The experiments carried out with three upstream slope (1:1, 1:2 and 1:3) and three downstream slope (vertical, 1:6 and 1:10), two step height (P = 7.62 and 15.62cm), constant throat width (w = 25cm) and throat length (L = 30.48cm). Eleven different models made of Plexiglas were tested in a horizontal flume for large range of discharges. The results achieved shows that the model has good ability to simulate the flow and to estimate discharge passing through long-throated flume. The average error in the estimation of discharge was 10 percent.

 
 
 
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Title:

The effects of time-moments and markov-parameters on reduced-order modeling

Author (s):

S. K. Mittal, Dinesh Chandra and Bharti Dwivedi

Abstract:

This note presents a study of the effect of time-moments and Markov-parameters on reduced order modeling and to identify suitable combination of time-moments and Markov-parameters to highlight the significance of retaining or near retaining a few terms (time-moments/Markov-parameters) in excess of r terms in arriving at a good overall time response approximation, where r denotes the order of the reduced-order model. To identify appropriate combination of time-moments and Markov-parameters of the system to be retained in the reduced-order model for obtaining good overall time response approximation, system under consideration are of  nature: Critically-damped system, under-damped system with small settling time  and under-damped system with large settling time.

 
 
 
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Title: Evaluation of heat loss coefficients in solar flat plate collectors
Author (s): Y. Rajasekhar, K. V. Sharma and M. Basaveswara Rao
Abstract:

Flat Plate Collectors (FPC) is widely used for domestic hot-water, space heating/drying, for applications requiring temperatures less than 100oC. The absorber plate of the FPC transfers solar energy to liquid flowing inside the tubes. The flow takes place by thermosyphon effect or by forcing water through the tubes. However, some of the energy absorbed by the plate is lost to the atmosphere as temperature of the plate is higher than the ambient temperature. The efficiency of FPC is dependent on the temperature of the plate which in turn is dependent on the nature of flow of fluid inside the tube, the emissivity of the plate and glass cover, wind loss coefficient, inclination of the FPC with respect to horizontal. The objective of the present work was to evaluate theoretically and experimentally the heat loss coefficient from flat plate collector. An experimental system was designed and fabricated to conduct experiments at different heat flux conditions. The effect of other significant parameters was evaluated by conducting the experiment.

 
 
 
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Title: Mixed convection flow in a rectangular ventilated cavity with a heat conducting square cylinder at the center
Author (s): Md. Mustafizur Rahman, Md. Elias and M. A. Alim
Abstract:

In this paper, a study of mixed convection flow inside a rectangular ventilated cavity in the presence of a heat conducting square cylinder at the center has been carried out. An external fluid flow enters the cavity through an opening in the left vertical wall and exits from another opening in the right vertical wall. The governing equations are transformed into non-dimensional form and the resulting partial differential equations are solved by the finite element method. Results are presented in the form of average Nusselt number of the heated wall, average temperature of the fluid in the cavity and temperature at the cylinder center for the range of Richardson number and cavity aspect ratio. The streamlines and isothermal lines are also presented.

 
 
 
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Title: Development and application of a machine vision system for measurement of surface roughness
Author (s): D. A. Fadare and A. O. Oni

Abstract:

Monitoring of surface roughness is an essential component in planning of machining processes as it affects the surface quality and dimensional accuracy of machined components. In this study, the development and application of a machine vision system suitable for on-line measurement of surface roughness of machined components using artificial neural network (ANN) is described. The system, which was based on digital image processing of the machined surface, consisted of a CCD camera, PC, Microsoft Windows Video Maker, frame grabber, Video to USB cable, digital image processing software (Photoshop, and MATLAB digital image processing toolbox), and two light sources. The images of the machined surface were captured; analyzed and optical roughness features were estimated using the 2-D fast Fourier transform (FFT) algorithm. A multilayer perceptron (MLP) neural network was used to model and predict the optical roughness values. Tool wear index and five features extracted from the surface images were used as input dataset in training and testing the ANN model. The results showed that the ANN predicted optical roughness values were found to be in close agreement with the calculated values (R2-value = 0.9529). Thus, indicating that the proposed machine vision system and ANN model are adequate for online monitoring and control of surface roughness in machining environment.

 
 
 
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Title: Experimental data analysis of five Moore 10000 class fans used in air cooled heat exchangers
Author (s): Seyed Sharif Khoshmanesh

Abstract:

Air-cooled heat exchanger that included the Moore 10000 class fans and tube bundle are used to cool the sour gas in Salman gas production platform in Iran. The objective of these fans is to produce enough pressure to overcome the friction through the bundle and proper air volume to cool the sour gas. Even if Number of blades give the rough estimation of produced pressure but blade angle is an important parameter to optimum the number of blades and to prepare an laminar flow through the blades to avoid the sever vibration. Effect of blade angle on static pressure, efficiency and flow rate for five models of these fans has been illustrated here. With increasing the blade angle the Static pressure rise and reach to maximum value, after that more increased in blade angle cause the static pressure start to drop off sharply. It is because of turbulent effect of flow on the blade that called the staling or burbling flow. Cyclic nature of this staling flow causes the severe vibration on blade. The flow rate and power consumption will increase while the blade angle increases. Howell criteria give an upper estimation of nearly 15-20 percent for losses of energy. For model 2 and model 3 that have four number of blades so lower relative to other models, deviation of Howell energy losses relative to real (measured) energy losses are high so Howell criteria is not applicable to axial fan with low number of blades. With increase in number of blades the Howell energy losses will close to real value. Model 2 with seven numbers of blades shows this fact.  Looking through the variation of flow coefficient and stage loading factor with blade angle it shows the maximum efficiency nearly in flow coefficient of 0.35 and loading factor of 0.25 will happen.

 
 
 
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Title: The optimization of number of Kanbans in GKCS with simulation technique
Author (s): N. Selvaraj
Abstract:

This paper presents to determine the optimum number of kanbans in Generalized Kanban Control System (GKCS) at three different demand frequencies and keeping the mean processing time as constant. The configuration of the single line with three manufacturing stages is assumed to have flow line production. The manufacturing system is modeled as network diagram of GKCS using discrete event simulation software i.e. Promodel. Simulations studies were performed for the three-stage GKCS model to find the optimum number of kanbans when the machines are subject to with and without breakdown. The optimum number of kanbans is selected in such a way that, where the throughput is maximum, the work in process is low and the machine utilization is high. The customer demand is assumed as 10,15 and 20minutes. Finally the obtained results are justified with GKCS properties.

 
 
 
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Title: Experimental investigations in a circular tube to enhance turbulent heat transfer using mesh inserts
Author (s): Naga Sarada S., Kalyani K. Radha and A. V. S. Raju

Abstract:

The present work shows the results obtained from experimental investigations of the augmentation of turbulent flow heat transfer in a horizontal tube by means of mesh inserts with air as the working fluid. Sixteen types of mesh inserts with screen diameters of 22mm, 18mm, 14mm and 10mm for varying distance between the screens of 50mm, 100mm, 150mm and 200mm in the porosity range of 99.73 to 99.98 are considered for experimentation. The Reynolds number is varied from 7000 to 14000. Correlations for Nusselt number and friction factor are developed for the mesh inserts from the obtained results. It is observed that the enhancement of heat transfer by using mesh inserts when compared to plain tube at the same mass flow rate is more by a factor of 2 times where as the pressure drop is only about a factor of 1.45 times.

 
 
 
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Title: Towards a low-cost autonomous object manipulation device
Author (s): P. Chand, M. Shazil and E. Kumar

Abstract:

This paper describes the development of a low-cost autonomous mobile robot for transporting distributed objects in a manufacturing application. A VEX mobile robot kit is utilized to design and construct a prototype robot that is employed in a model object transfer task. For autonomous operation, the behaviour-based programming method is employed to build two complex behaviours that are sequentially executed. The performance of the designed robot is evaluated by measuring the time taken to transport up to five objects to the goal location. Experimental results indicate that the prototype robot can successfully transport objects to the goal and re-grasp unsuccessfully manipulated objects.

 
 
 
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Title: Metallic fiber reinforced concrete: effect of fiber aspect ratio on the flexural properties
Author (s): Rashid Hameed, Anaclet Turatsinze, Frédéric Duprat and Alain Sellier

Abstract:

Since many decades efforts have been made to reduce the brittleness of cementitious materials by the use of micro and macro fibers of different mechanical, geometrical and physical properties. This contribution presents the results of an experimental investigation carried out to study the effect of fiber aspect ratio on the flexural properties of metallic fiber reinforced concrete (MFRC). The flexural properties, which have been studied, include maximum load bearing capacity (peak load), post-crack strength and flexural toughness. High performance metallic fibers of different aspect ratios were used. The dosage of fibers was kept 20 kg/m3 (0.25% by volume fraction) for all the fibered concrete mixtures. Three point bending tests were performed on both control (without fibers) and fibered notched prismatic concrete specimens of cross section 100 x 100mm and clear span of 450mm. The results showed that the flexural properties of concrete matrix are significantly improved by the addition of high performance metallic fibers. Moreover, it was found that the level of improvement in flexural properties of MFRC varies with the aspect ratio of fibers. Out of the two different aspect ratios of metallic fibers used in this study, the fibers with larger aspect ratio showed better efficiency in improving the flexural response of MFRC.

 
 
 
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Title: Low voltage ride-through (LVRT) of grid interfaced wind driven PMSG
Author (s): Rajveer Mittal, K. S. Sandhu and D. K. Jain

Abstract:

In renewable power generation, wind energy has been noted as the most rapidly growing technology; it attracts interest as one of the most cost-effective ways to generate electricity from renewable sources. Wind generation system has potential application for the grid support. The voltage of the direct driven permanent magnet wind generators (PMSG) is variable due to the intermittent nature of the wind energy. Fluctuating voltage and power is of major concern in the converter based grid connected wind generation systems. An inverter is essential for the interfacing of the wind source with the AC network. There are many possible inverter topologies and inverter switching schemes and each one will have its own relative advantages and disadvantages. Variable speed permanent magnet synchronous generators are used for maximum power extraction from the wind energy conversion system. This paper discusses the interconnection issues of these generators to local grid as per prevailing grid standards during healthy and fault conditions. The fault ride-through topology for PMSG has been demonstrated using MATLAB Simulink based simulation.

 
 
 
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Title: Compressibility of single un-rendered rice straw bales: Characteristics of bales used for building
Author (s): Gihan L. K. Garas, Mostafa E. Allam, Hala G. El Kady and Ayman H. El Alfy

Abstract:

Straw bale construction has recently gained more confidence to be used as structural elements. A number of laboratory tests worldwide, show this system to be capable of supporting substantial service loads in case of proper baling, stacking, and plastering. In Egypt, growing attention is focused on examining this new trend of construction in order to solve the environmental pollution caused by burning millions of tons of straw every year. Two types of mobile straw baling mechanical powered press machines are commonly used in Egypt, private local small sized iron baling machines and Cicoria straw baling machines. These two baling systems have major differences in their end product physical properties, baling, and mainly their compressing techniques. Rare information is available about the mechanical characteristics of local bales. This paper is part of a pioneer national project aiming to use rice straw bales in building. The research aims to identify the specifications and characteristics of locally produced rice straw bales used for building. The bales are compressed under various compressibility conditions to identify the settlement that is expected to happen in most of the types of bales available in the market. Experimental studies are carried out on the effect of compressibility and baling on the quality of single un-rendered straw bales in general, and particularly it's displacement under vertical load. These experiments are conducted on single un-rendered bales from different sources, by applying incremental vertical load, reaching 50 tons. Results of corresponding displacements of different types of bales from different sources are recorded and compared together. It was found that bales compressed by private local small sized iron factories show the least displacement values that did not exceed 3.0cm when subject to a maximum of 50 ton vertical load. Finally, recommendations are given for safe application of such bales in construction.

 
 
 
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Title: Design and simulation of fuzzy controlled quasi resonant buck converter
Author (s): A. Rameshkumar and S. Arumugam

Abstract:

A controller based on Fuzzy logic is implemented and its application to the regulation of power converter is investigated. Being free of complex equations and heavy computation, it achieves fast dynamic response and adapts to varying conditions of operation. The topology is modeled using MATLAB software and operated at finite higher switching frequency to evaluate its closed-loop performance in respect of line and load regulation. It is verified by transient characteristics that due to quasi-resonance there is a drastic change in peak overshoot and settling time and the proposed strategy has good rejection ability for supply and load disturbances.

 
 
 
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Title: Telemetric control of traffic lights intersections aspect ratio in Ghana
Author (s): Erwin Normanyo, Neville Dodoo-Quartey and Adetunde Isaac

Abstract:

This paper presents the current operation and maintenance of traffic light intersections and the design of a telemetry system to monitor and control traffic light intersections in the Accra metropolis. Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. The design of a telemetry system constitutes the selection of a suitable hardware system and the appropriate software for the design of a human machine interface (HMI) to monitor the state of traffic light intersections and taking appropriate actions to resolve faulty traffic light intersections.

 
 
 
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