Engineering & Materials Sciences
http://www.niscair.res.in; http://nopr.niscair.res.in
VOLUME 16
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NUMBER 4
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AUGUST 2009
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CODEN
: IEMSEW |
ISSN : 0971-4588 |
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CONTENTS
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Engineering |
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Mathematical model and rule extraction for tool wear monitoring problem |
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using nature inspired techniques |
205 |
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Mean flow field measurements in an axisymmetric conical diffuser with and |
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without inlet
flow distortion |
211 |
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Seismic performance evaluation methodologies for civil engineering structures |
220 |
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C
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CFD approach for design optimization and validation for axial flow |
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hydraulic turbine |
229 |
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Artificial neural networks for predicting low temperature performances of |
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modified asphalt mixtures |
237 |
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Bridge truss optimization under moving load using continuous and |
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discrete design variables in optimization methods |
245 |
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Discrete singular convolution algorithm for non-linear transient response of |
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circular plates resting on Winkler-Pasternak elastic foundations |
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with different types of dynamic loading |
259 |
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Use of lime cement
stabilized pavement construction |
269 |
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Materials Science |
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Simple fabrication of Mg2Si thermoelectric generator by spark plasma sintering |
277 |
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Nanostructured silver-graphite electrical contact materials processed |
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by mechanical milling |
281 |
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Preparation and characterization of nickel doped, A and B Site LaCoO3 perovskite |
288 |
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Indian
Journal of Engineering & Materials Sciences
Vol.16,
August 2009, pp. 205-210
Mathematical model and rule extraction for tool wear monitoring problem using nature inspired techniques
S N Omkar, J Senthilnath &
In this paper, pattern classification problem in tool wear monitoring is solved using nature inspired techniques such as Genetic Programming (GP) and Ant-Miner (AM). The main advantage of GP and AM is their ability to learn the underlying data relationships and express them in the form of mathematical equation or simple rules. The extraction of knowledge from the training data set using GP and AM are in the form of Genetic Programming Classifier Expression (GPCE) and rules respectively. The GPCE and AM extracted rules are then applied to set of data in the testing/validation set to obtain the classification accuracy. A major attraction in GP evolved GPCE and AM based classification is the possibility of obtaining an expert system like rules that can be directly applied subsequently by the user in his/her application. The performance of the data classification using GP and AM is as good as the classification accuracy obtained in the earlier study (i.e. using ANN approach).
Keywords: Tool wear monitoring; Genetic Programming; Ant-Miner
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 211-219
Mean flow field measurements in an axisymmetric conical
diffuser with and without inlet flow distortion
The prime
objective of this paper is to present the details of the experimental
investigation and measurements made in an axisymmetric 5° conical diffuser model. The flow through a
diffuser is studied with and without the inlet flow distortion. A simple
cylindrical bluff body placed at the inlet of the diffuser creates the inlet
flow distortion. A
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 220-228
Seismic performance evaluation methodologies for civil engineering structures
C
There is a strong need for evaluating the adequacy of seismic performance of civil engineering structures following the damage and collapse of numerous structures during recent earthquakes. In addition, the adequacy of seismic performance of the older structures in regions of high seismicity, which are designed prior to the advent of revised seismic deign codes, is also a matter of growing concern. Seismic performance evaluation of civil engineering structures is an iterative process involving alternate stages of experimentation and computation. Several experimental methodologies including quasi-static testing, effective force testing, shake table testing, pseudo dynamic testing and real time dynamic hybrid testing and computational methodologies based on different numerical time stepping procedures are used to simulate and evaluate the seismic performance of civil engineering structures. In this paper a broad overview on the existing computational and experimental seismic performance evaluation methodologies is reported. The paper also presents the genesis, development and mathematical formulation of the pseudo dynamic testing method in detail and highlights the merits and demerits of the method over the other experimental seismic performance evaluation methods.
Keywords: Seismic performance, performance evaluation, earthquake engineering, shake table testing, effective force testing, pseudo dynamic testing, real time dynamic hybrid testing.
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 229-236
CFD approach for design optimization
and validation for
axial flow hydraulic turbine
Vishnu Prasad, V K Gahlot & P Krishnamachar
The conventional method to assess turbine performance is its model testing which becomes costly and time consuming for several design alternatives in design optimization. Computational fluid dynamics (CFD) has become a cost effective tool for predicting detailed flow information in turbine space to enable the selection of best design. In the present paper, 3D real flow analysis in an experimentally tested axial flow turbine has been carried out and different flow parameters are computed at three operating regimes to find the best operating regime. The computed efficiencies are critically compared with experimental values and found to bear close comparison.
Keywords : Computational fluid dynamics, Efficiency, Lift, Blade circulation, Degree of reaction
Indian
Journal of Engineering & Materials Sciences
Vol.16,
August 2009, pp. 237-244
Artificial neural networks for predicting low temperature performances of modified asphalt mixtures
Yuksel Tasdemir
In this study, the
estimation of the low temperature performance of modified asphalt mixtures is
investigated by using multi-layer perceptrons (MLP) which is one of the
artificial neural networks (ANNs) techniques and general linear model (GLM).
The fastest MLP training algorithm, that is the Levenberg-Marquardt algorithm,
is used for optimization of the network weights. The ANN test results are
compared to GLM results. GLM has, historically, been used to model the low
temperature performance (fracture temperature and fracture strength) of asphalt
pavements. The data used in the ANN model and GLM are arranged in a format of
four input parameters that cover additive type, asphalt binder content, aging
level and air void content, and output parameters which are the fracture
temperature and the fracture strength. Based on the comparisons, it is found
that the ANN generally gives better fracture temperature and fracture strength
estimates than the GLM technique.
Keywords: Artificial neural network; General linear
model; Thermal stress restrained specimen test; Fracture temperature; Fracture
strength
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 245-258
Bridge truss optimization under moving load using continuous and discrete design variables in optimization methods
Vedat Toğan & Ayşe T Daloğlu
The aim of this work is to minimize the weight of steel bridge trusses under the limitations imposed on its behaviour by the design codes when it is subjected to moving load (HS20-truck). Adaptive manner operators are included to enhance the capability of GA. Design examples are solved to illustrate the applicability of proposed algorithm. Results are compared with those evaluated by various optimization methods with continuous design variables such as sequential convex programming (SCP), sequential quadratic programming (SQP) and evolution strategy (EVOL). It can be concluded that the results obtained by GA is meaningful, more suitable for practice and GA performs well to find minimum weight of the bridge trusses under moving load.
Keywords: Bridge truss; Optimization methods; Evolutionary computation; Genetic algorithm
Vol. 16, August 2009, pp
259-268
Discrete singular convolution algorithm for non-linear transient response of circular plates resting on Winkler-Pasternak elastic foundations with different types of dynamic loading
Ömer Civalek & Baki
Öztürk
Nonlinear dynamic analysis of circular plates on two parameter elastic
foundations is studied. Winkler and Pasternak models of elastic foundation are
used. The nonlinear partial differential equations obtained from von Karman’s
large deflection plate theory have been solved by using the discrete singular convolution (DSC) in
the space domain and the harmonic
differential quadrature (HDQ) method in the time domain. The influence
of stiffness of Winkler (K) and Pasternak (G) foundation on
geometrically nonlinear dynamic response of plates is investigated. The
influence of damping on the nonlinear dynamic response has also been studied.
Numerical results obtained by the application of present technique compare well
with the results available in literature.
Keywords: Discrete
singular convolution, Circular plates, Harmonic differential quadrature, Nonlinear
transient analysis, Winkler-Pasternak elastic foundation
Vol. 16, August 2009, pp. 269-276
Use of lime cement
stabilized pavement construction
M Anjan Kumar & G V R Prasada
Raju
Expansive clay is a major source of heave induced structural distress.
Swelling of expansive soils causes serious problems and produce damages to many
structures. Many research organizations are doing extensive work on waste
materials concerning the feasibility and environmental suitability. Fly ash, a
waste by product from coal burning in thermal power stations is abundant in
Keywords: Expansive soil, Fly ash, Lime,
Cement, Flexible pavement
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 277-280
Simple fabrication of Mg2Si thermoelectric
generator by
spark plasma sintering
M J Yang, L M Zhang, L Q Han, Q Shen & C B Wang
Raw Mg and Si powders have been used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering (SPS). The optimum parameters to synthesize pure Mg2Si are found to be 823 K-0 MPa-10 min with excessive content of 10wt% Mg from the stoichiometric Mg2Si. Mg2Si bulk has been firstly synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder, but Mg and Si not react completely, and the sample is not very dense with some microcracks on the surface. Then, Mg and Si powders firstly reacted at 823 K-0 MPa-10 min in SPS chamber to form Mg2Si green compact, again sintered by SPS at 1023 K-20 MPa-5 min. The fabricated sample only contained Mg2Si phase with high relative density (nearly 100%).
Keywords: Mg2Si, Spark Plasma Sintering
Indian
Journal of Engineering & Materials Sciences
Vol.
16, August 2009, pp. 281-287
Nanostructured silver-graphite
electrical contact materials processed
by mechanical milling
Bharati R Rehani, P
B Joshi & V K Kaushik
In last few decades there has been a growing interest in nanostructured materials in view of their improved mechanical, physical and chemical properties. A wide variety of techniques have been developed to synthesize nanopowders including high-energy milling or mechanical alloying (MA) for producing bulk nanostructures. High-energy milling is used for preparation of elemental and composite powders of different metals and non-metals. Literature reports the synthesis of ductile-ductile composites such as aluminium-graphite and copper-graphite by MA owing to its potential benefits in terms of improved mechanical properties. Reports are also there on the application of this technology for processing of silver-graphite contact materials offering improved switching properties.
Indian
Journal of Engineering & Materials Sciences
Vol.16,
August 2009, pp. 288-290
Preparation and characterization of nickel doped, A and B Site LaCoO3 perovskite
Chandrakant Singh & Meeta Rakesh
This paper presents an approach to the preparation of LaCoO3 perovskite and nickel doped LaCoO3 in A and B site both, to see the effect of nickel doping in both the site catalyst synthesized by co-precipitation method. The novelty of the experiment is nickel doped in A-site of LaCoO3 perovskite to see effect of nickel doping into their physical properties (i.e. crystalline phase and microstructure). Samples have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Branauer–Emmett-Teller (BET) nitrogen adsorption technique.
Keywords: Perovskite; LaCoO3, La1-x Ni xCoO3 , LaCo1-y NiyO3; Co-precipitation method