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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