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Search Results: 1 - 10 of 219589 matches for " C.;Sivaramakrishnan "
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Modeling and optimization of cylindrical grinding of Al/SiC composites using genetic algorithms
Thiagarajan, C.;Sivaramakrishnan, R.;Somasundaram, S.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000100005
Abstract: the al/sic composites have received more commercial attention than other kinds of metal matrix composites (mmcs) due to their high performance. however, a continuing problem with mmcs is that they are difficult to machine, due to the hardness and abrasive nature of the sic particles. grinding is often the method of choice for machining al/sic composites to acquire high dimensional accuracy and surface finish in large scale production. based on the full factorial design (34), a total of 81 experiments, each having a combination of different levels of variables, are carried out to study the effect of grinding parameters such as wheel velocity, work piece velocity, feed and depth of cut on the responses such as tangential grinding force, roughness and grinding temperature. modeling and optimization place a vital role in controlling any process for improved product quality, high productivity and low cost. in the present work, experimental results are used to calculate the analysis of variance (anova) which explains the significance of the parameters on the responses. based on the results of anova, a mathematical model is formulated using multiple regression method. a genetic algorithm (ga) based optimization procedure has been developed to optimize the grinding parameters for maximum material removal by imposing constraints on roughness. this methodology would be useful for identifying the optimum grinding parameters in order to achieve the required material removal rate (mrr).
Cylindrical grinding of SiC particles reinforced aluminium metal matrix composites
C. Thiagarajan,R. Sivaramakrishnan,S. Somasundaram
Journal of Engineering and Applied Sciences , 2011,
Abstract: This paper deals with an experimental study on the grindability of Al/SiC metal matrix composites in cylindrical grinding. Machining of metal matrix composites (MMCs) is an area to be focused and finishing processes such as grinding to obtain a good surface finish and damage-free surfaces are crucial for the application of these materials. Nevertheless, grinding of MMCs has received little attention so far, thereby a detailed study on that has been carried out. In the present work, experiments are carried out to study the effect of grinding parameters; wheel velocity, work piece velocity, feed and depth of cut and SiC volume fraction percentage on the responses; grinding force, surface roughness and grinding temperature. Surface integrity of the ground surfaces is assessed using a scanning electron microscope (SEM). There are no cracks and defects found on the cylindrical ground surfaces at high wheel and work piece velocities, low feed and depth of cut.
A Study on Microhardness, Microstructure and Wear Properties of Plasma Transferred Arc Hardfaced Structural Steel with Titanium Carbide  [PDF]
Balamurugan Sivaramakrishnan, Murugan Nadarajan
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2014, DOI: 10.4236/jmmce.2014.23020
Abstract: The Plasma Transferred Arc (PTA) hardfacing allows for homogeneous refined microstructure, low distortion and dilution resulting on enhanced surface properties when compared to hardfacing by conventional welding processes. This paper deals with PTA surfacing of a structural steel with a consumable containing TiC. TiC is a very hard refractory material finding increasing usage for wear resistance application. The composition and amount of heat input evidently affect the microstructure and properties of the hardfacing. The microstructure and microhardness of PTA hardfaced structural steel with TiC were investigated at different heat input conditions across the various zones. The influence of hardfacing parameters on the resulting microstructure, microhardness and wear resistance performance was evaluated. Wear resistance of the hardfaced surface was increased significantly.
Spanning trees in complete uniform hypergraphs and a connection to extended r-Shi hyperplane arrangements
Sivaramakrishnan Sivasubramanian
Mathematics , 2006,
Abstract: We give a Cayley type formula to count the number of spanning trees in the complete r-uniform hypergraph for all r >= 3. Similar to the bijection between spanning trees in complete graphs and Parking functions, we derive a bijection from spanning trees of the complete (r+1)-uniform hypergraph which arise from a fixed r-perfect matching and r-Parking functions. We observe a simple consequence of this bijection in terms of the number of regions of the extended Shi arrangement.
Interpreting the two variable Distance enumerator of the Shi hyperplane arrangement
Sivaramakrishnan Sivasubramanian
Mathematics , 2006,
Abstract: We give an interpretation of the coefficients of the two variable refinement $D_{\Sh_n}(q,t)$ of the distance enumerator of the Shi hyperplane arrangement $\Sh_n$ in $n$ dimensions. This two variable refinement was defined by Stanley \cite{stan-rota} for the general $r$-extended Shi hyperplane arrangements. We give an interpretation when $r=1$. We define three natural three-dimensional partitions of the number $(n+1)^{n-1}$. The first arises from parking functions of length $n$, the second from special posets on $n$ vertices defined by Athanasiadis and the third from spanning trees on $n+1$ vertices. We call the three partitions as the parking partition, the tree-poset partition and the spanning-tree partition respectively. We show that one of the parts of the parking partition is identical to the number of edge-labelled trees with label set $\{1,2,...,n\}$ on $n+1$ unlabelled vertices. We prove that the parking partition majorises the tree-poset partition and conjecture that the spanning-tree partition also majorises the tree-poset partition.
Ground-Based Coronagraphy with High Order Adaptive Optics
A. Sivaramakrishnan,C. D. Koresko,R. B. Makidon,T. Berkefeld,M. J. Kuchner
Physics , 2001, DOI: 10.1086/320444
Abstract: We summarize the theory of coronagraphic optics, and identify a dimensionless fine-tuning parameter, F, which we use to describe the Lyot stop size in the natural units of the coronagraphic optical train and the observing wavelength. We then present simulations of coronagraphs matched to adaptive optics (AO) systems on the Calypso 1.2m, Palomar Hale 5m and Gemini 8m telescopes under various atmospheric conditions, and identify useful parameter ranges for AO coronagraphy on these telescopes. Our simulations employ a tapered, high-pass filter in spatial frequency space to mimic the action of adaptive wavefront correction. We test the validity of this representation of AO correction by comparing our simulations with recent K-band data from the 241-channel Palomar Hale AO system and its dedicated PHARO science camera in coronagraphic mode.
Determination of cetane number of biodiesel and it’s influence on physical properties
P. Ravikumar,K. Sivaramakrishnan
Journal of Engineering and Applied Sciences , 2012,
Abstract: Biodiesel, an alternative fuel can be used in diesel engine as neat or blended with diesel. The physio-chemical properties of fuel are important in design of fuel system for compression ignition engine run on diesel, biodiesel or biodiesel blends. Cetane number is an important parameter in evaluating the quality of biodiesel fuel. Its determination is usually arduous and expensive. The present study is aimed at developing the mathematical relationship between viscosity, density, calorific value, flash point and cetane number (CN). An equation was developed relating the cetane number and thermal properties. The predicted cetane number values are compared with the measured cetane number values. This work establishes the general dependence of cetane number on the thermal properties of biodiesel.
Single Monocular Moving Camera based 3-D Segmentation
R. Senthilnathan,R. Sivaramakrishnan
International Journal of Electronics and Computer Science Engineering , 2012,
Abstract: Three dimensional (3-D) vision techniques in the field of Computer Vision aims mainly at reconstructing a scene to find its three dimensional geometrical information. Passive 3-D vision techniques such as computational stereo vision method do surface reconstruction from disparities arising in images of the same scene taken from multiple views. For reconstruction leading to metrical information of the 3-D geometry of the scene the camera pose with respect to some world reference frame and the camera parameters such as the focal length, sensor size has to be accurately known. Such information especially the pose of the camera might not be known in many applications such as in agricultural, underwater explorations since a unique universal frame of reference is not possible. Also the constancy of the internal camera parameters will not be valid in many applications requiring good accuracy in reconstruction. In such cases the cameras used for passive triangulation is said to be un-calibrated. Stereo vision technique generally requires two images and which need not be from two different cameras. The paper is an attempt to use a single moving camera with which the image of the same scene is acquired from two different views. Since the scene geometry and the pose of the camera are unknown the problem to be addressed is close to so called Structure from Motion (SfM) problem in Computer Vision. The reconstruction method developed in the paper is extended further to segment top surfaces of cuboid shaped object considered as the object of interest in the scene reconstruction process. Though the information in the case considered is non-metrical the applications that pose such un-calibrated camera as a demand are plenty.
Investigation on performance and emissions of a biodiesel engine through optimization techniques
Kaliyamoorthy Sivaramakrishnan,Paramasivam Ravikumar
Thermal Science , 2013, DOI: 10.2298/tsci120105151k
Abstract: The study is aimed at investigating the effects of engine parameters on the performance and emission characteristics of a single cylinder 5.2 kW diesel engine. The experiments were designed using a statistical tool known as design of experiments based on taguchi. Five parameters, namely ,Power (P), Static injection pressure (IP), Injection timing (IT), Fuel Fraction (B) and compression ratio (CR) were varied at four levels and the responses brake power, fuel economy and emissions were investigated. The optimum n values of the response could be predicted using Signal - Noise ratio(S/N ratio) and optimum combination of control parameters were specified. Results of confirmation tests showed good agreement with predicted quantities. A compression ratio of 17.7, blend of 20% karanja biodiesel (B20), an injection pressure of 230 bar, injection timing of 27° bTDC and at 70% Load were found to be optimal values for the karanja biodiesel blended diesel fuel operation in the test engine.
Web Mining Functions in an Academic Search Application
Informatica Economica Journal , 2009,
Abstract: This paper deals with Web mining and the different categories of Web mining like content, structure and usage mining. The application of Web mining in an academic search application has been discussed. The paper concludes with open problems related to Web mining. The present work can be a useful input to Web users, Web Administrators in a university environment.
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