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Search Results: 1 - 10 of 144410 matches for " B. RAMAMOORTHY "
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An Investigation into the Adhesion Strength of Diamond Like Carbon Multilayer Coating (DLC/TiN/Ti/Cu/Ni)  [PDF]
B. RAMAMOORTHY, BINU C. YELDOSE
Intelligent Information Management (IIM) , 2009, DOI: 10.4236/iim.2009.13027
Abstract: Advancement in vacuum technologies and vapor deposition processes during last decades has led to the introduction of many modern coatings on metal cutting tools. Even in such an advanced vacuum coating techniques, the failure is not due to the wear of the coating but rather due to the lack of coating adhesion to the substrate. In this work, the coating adhesion test results were performed which is based on the Rockwell indentation tests. This coating adhesion tests were performed as per VDI standards 3198, 1991 for d.c. magnetron sputter deposition of diamond like carbon multilayer coating (DLC / TiN/ Ti / Cu / Ni) on tool substrate. Multilayer coating was deposited on tool substrates at different sputtering parameters/conditions such as power density, partial pressure, substrate temperature and reactive gases. The coated multilayer films were characterized by experimental techniques such as X-ray diffractometer which measures the material deposited, micro Raman spectroscopy and TEM to check DLC, Rockwell indentation to examine adhesion strength, optical profilometer to measure thickness of coating. Ni increases the Cu adhesion on tool substrate. Cu accommodates the shear stress induced by the films / substrate and the mismatch in thermal expansion coefficient, while Ti and TiN promote better DLC bonding. As the target power was increased the adhesion strength, micro hardness and deposition rate were observed to improve. Increase in target power and substrate temperature enhances adhesion strength. Proper substrate preparation and sequence of cleaning processes are the crucial factors for the enhancement of adhesion strength. The sputter deposition conditions for the above mentioned multilayer coatings are identified in this work to get improved quality with particular reference to adhesion and surface finish.
Optimization of Surface Milling of Hardened AISI4340 Steel with Minimal Fluid Application Using a High Velocity Narrow Pulsing Jet of Cutting Fluid  [PDF]
K. Leo Dev Wins, A. S. Varadarajan, B. Ramamoorthy
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.210102
Abstract: Surface milling of hardened steel is carried out with copious supply of cutting fluid and is obviously associated with problems related to procurement and storage of cutting fluid. The disposal of cutting fluid has to comply with environmental legislation such as OSHA regulations. The present investigation proposes an environment friendly minimal pulsed jet cutting fluid application scheme for surface milling of AISI4340 steel with a hardness of 45 HRC using commercially available carbide tools. This scheme can be implemented as such on the shop floor with out the need for any major alternations on the existing facilities and it was observed that the new scheme is not only environment friendly but also provided better cutting performance when compared to conventional wet milling which requires copious supply of cutting fluid.
Minimization of Switching Devices and Driver Circuits in Multilevel Inverter  [PDF]
S. Jawahar, P. Ramamoorthy
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.710287
Abstract: The various configurations of multilevel inverter involve the use of more numbers of switching devices, energy storage devices and/or unidirectional devices. Each switching unit necessitates the add-on driver circuit for proper functionality. Cascaded H-Bridge Multilevel Inverter requires overlapped switching pulses for the switching devices in positive and negative arms of the bridge which may lead to short circuit during the device failure. This work addresses the problems in different configurations of multilevel inverter by using reduced number of switching and energy storage devices and driver circuits. In the present approach Single Switch is used for each stair case positive output and single H-Bridge for phase reversal. Driver circuits are reduced by using the property of body diode of the MOSFET. Switching pulses are generated by Arduino Development Board. The circuit is simulated using Matlab. More so, through experimental means, it is physically tested and results are analyzed for the 5-step inverter and thereby simulation is fully validated. Consequently, cycloconverter operation of the circuit is simulated using Matlab. Moreover, half bridge configuration of the multilevel inverter is also analyzed for high frequency induction heating applications.
Effect of High Speed Cutting Parameters on the Surface Characteristics of Superalloy Inconel 718
D. G.Thakur,B. Ramamoorthy,L. Vijayaraghavan
Lecture Notes in Engineering and Computer Science , 2010,
Abstract:
Communicating the sum of sources over a network
Aditya Ramamoorthy
Mathematics , 2008,
Abstract: We consider a network (that is capable of network coding) with a set of sources and terminals, where each terminal is interested in recovering the sum of the sources. Considering directed acyclic graphs with unit capacity edges and independent, unit-entropy sources, we show the rate region when (a) there are two sources and $n$ terminals, and (b) $n$ sources and two terminals. In these cases as long as there exists at least one path from each source to each terminal we demonstrate that there exists a valid assignment of coding vectors to the edges such that the terminals can recover the sum of the sources.
Minimum cost distributed source coding over a network
Aditya Ramamoorthy
Mathematics , 2007,
Abstract: This work considers the problem of transmitting multiple compressible sources over a network at minimum cost. The aim is to find the optimal rates at which the sources should be compressed and the network flows using which they should be transmitted so that the cost of the transmission is minimal. We consider networks with capacity constraints and linear cost functions. The problem is complicated by the fact that the description of the feasible rate region of distributed source coding problems typically has a number of constraints that is exponential in the number of sources. This renders general purpose solvers inefficient. We present a framework in which these problems can be solved efficiently by exploiting the structure of the feasible rate regions coupled with dual decomposition and optimization techniques such as the subgradient method and the proximal bundle method.
Extraction of Atrial and Pulmonary Thrombi Using Angiovac Aspiration System with Transesophageal Echocardiography and Fluoroscopic Guidance  [PDF]
Saravanan Ramamoorthy, Saifeldin Ahmed Mahmoud, Kane High
Open Journal of Anesthesiology (OJAnes) , 2017, DOI: 10.4236/ojanes.2017.76017
Abstract: Surgical embolectomy is widely used to treat massive or submassive pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension. [1]-[3] However, recently a new minimally invasive transvenous approach to clot evacuation using the AngioVac aspiration system (Vortex Medical, Norwell, Massachusetts) such as AngioVac aspiration system has been successfully used for retrieval of right atrial clot [4]-[6]. This is the first case report describing evacuation of trans-septal thrombus using an AngioVac aspiration system utilizing transesophageal echocardiograph (TEE) and fluoroscopic guidance. This case report also highlights the potential complications involved in AngioVac system which were readily diagnosed using TEE. We present a 66-year-old Caucasian female with a right atrial thrombus extending into left atrium through a patent for ovale (PFO) defect and a pulmonary artery thrombus. She underwent suction evacuation with an AngioVac aspiration system under TEE and fluoroscopic guidance. The right atrial thrombus extending into left atrium through a PFO was successfully evacuated through the PFO. However, the evacuation of the clot in the pulmonary artery was complicated by a rupture of the right ventricle requiring emergent sternotomy, cardiopulmonary bypass (CPB) and transient extracorporeal mechanical oxygenation (ECMO) support. The patient rapidly improved post-operatively and was discharged from hospital. Echocardiographic documentation of right heart thrombus and pulmonary emboli has poor prognostic implications. This report delineates the utility of TEE for visualization of cannula placement and real time aspiration of clots through the cannula. Potential complications associated with this technique are mechanical dislodge of thrombus from its attachment with subsequent embolization and rupture of cardiac chambers. Accessing the thrombus in the PA can be challenging and actual visualization of the cannula in the PA is often difficult and available only through TEE. This report highlights the utility of TEE for demonstrating trans-septal clot and the importance of precise positioning of cannula in avoiding complications. In spite of complications, AngioVac aspiration system under TEE and fluoroscopic guidance may become a safe alternative for surgical removal of intracardiac thrombi.
Medicinal Strength of Pahalgam Valley of Northern Himalayan Kashmir, India
BILALAHMAD BAIG,D. RAMAMOORTHY
Golden Research Thoughts , 2012, DOI: 10.9780/22315063
Abstract: The medicinal properties of plant species have made an outstanding contribution in the origin and evolution of many traditional herbal therapies. These traditional knowledge systems have started to disappear with the passage of time due to scarcity of written documents and relatively low income in these traditions. Over the past few years however the medicinal plants have regained a wide recognition due to an escalating faith in herbal medicine in view of its lesser side effects compared to allopathic medicine and the necessity of meeting the requirements of medicine for an increasing human population. The Pahalgam valley of Kashmir is the Northern most part of the Himalaya. The vegetational wealth of Northern Himalaya is well known since ancient times due to varying topographic conditions of the region thrive on different types of vegetation. It has a rich medicinal plant flora of over one thousand documented species having medicinal value. Out of these more than 700 species are much in use in the country, mostly by local people living in the villages as a household remedy in several diseases. The forests and alpines are getting degraded with the increasing biotic pressure and in the process ground flora and shrubs which happen to provide bulk of the medicinal plants are also under strain. In the present study a field survey was made from May to October of 2011 in Pahalgam valley of Kashmir in order to refine the medicinal strength of above places. The altitudinal range, local name, part used, use/cure and status of some important medicinal plants are compiled based on the earlier publications as well as personal communication with local persons, rural folks and Hakims.
ONLINE PUBLISHING CURRENT SCENARIO
Balasubramanian Thiagarajan,Geetha Ramamoorthy
Otolaryngology Online Journal , 2012,
Abstract: This article attempts to unravel the current scenario in online publishing. Advent of internet has brought with it tremendous changes in the publishing industry. What was hither to an industry dominated by publisher has been thrown open to one and sundry. Online publishing has brought with it a reach which was hitherto never been imagined. In the normal course it would take at least a year to publish a manuscript. Online publishing has managed to bring this time down to a few weeks / at most a month. This article attempts to discusses the positives and perils of online publishing scenario.
MALIGNANT GROWTH MAXILLA MANAGEMENT AN ANALYSIS
Balasubramanian Thiagarajan,Geetha Ramamoorthy
Otolaryngology Online Journal , 2013,
Abstract: Malignant tumors involving maxilla is rather rare. This comprises about 1% of all malignant tumors seen in humans. This tumor constitutes roughly 3% of all head and neck malignancies. This article discusses our experience in managing patients with malignant tumors of maxilla. All our patients underwent total maxillectomy followed by post operative irradiation. Mean survival rates of our patients ranged from 2.5 years to 3 years. Survival rates were also dependent on the histology of the tumor. This is a retrospective study of patients who presented to our Institution between 2006-2010.In our study we found that surgery had a definitive role despite the staging. Even advanced cases had a definite improvement in the quality of life. All our patients received post operative irradiation (full course) following total maxillectomy.
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