oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 1 )

2019 ( 77 )

2018 ( 121 )

2017 ( 99 )

Custom range...

Search Results: 1 - 10 of 50612 matches for " Y. Ramamurthy "
All listed articles are free for downloading (OA Articles)
Page 1 /50612
Display every page Item
Recovery of Chromite Values from Plant Tailings by Gravity Concentration  [PDF]
Sunil Kumar Tripathy, Y. Ramamurthy, Veerendra Singh
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.101002
Abstract: Large tonnages of chromite tailing were discarded during processing of chromite ore in the conventional circuit. A typical chromite plant tailing was treated in wilfley table for the recovery of chromite values. Optimisation study was carried out for the process parameters of wilfley table using empirical models, developed from the experimental data. It was found that grade and recovery (% Cr2O3) in the concentrate fraction majorly depended on the variation of deck tilt angle. To achieve high grade (>45%) with acceptable recovery (>40%), set of optimisation condition of parameters have derived which resulted large quantity of wash water (>5lpm of flow rate) is necessary. Validation of the empirical models were done with set of tests which resulted good agreement with the predict values (R2 is 0.96 and 0.99 for the grade and recovery respectively).
Application of High Tension Roll Separator for the Separation of Titanium Bearing Minerals: Process Modeling and Optimization  [PDF]
Srijith Mohanan, Sunil Kumar Tripathy, Y. Ramamurthy, C. Raghu Kumar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.1110103
Abstract: The High Tension Roll Separator (HTRS) is one of the main electrostatic unit operations employed to separate titanium minerals like ilmenite, rutile and leucoxene which behave as conducting from zircon, sillimanite, garnet and monazite which behave as non-conducting minerals when a high potential difference is applied. Three process inputs, namely roll speed, feed material temperature and roll speed have been optimized. Experiments were conducted based on the Box- Behnken factorial design; the results were analyzed using response surface methodology (RSM). A new term, called Operational Quality Index (OQI) has been defined as a process output, which is maximized by quadratic programming, to obtain the optimum operating conditions. The maximum value of OQI obtained under the constraints of grade >96% and recovery >98% is 195.53, at the following operating conditions—Temperature: 102°C, Feed Rate: 1.75 tph and Roll Speed: 132 rpm. Under these conditions, the grade and recovery obtained are 96.6% and 98.9% respectively.
Beyond L2-Loss Functions for Learning Sparse Models
Karthikeyan Natesan Ramamurthy,Aleksandr Y. Aravkin,Jayaraman J. Thiagarajan
Mathematics , 2014,
Abstract: Incorporating sparsity priors in learning tasks can give rise to simple, and interpretable models for complex high dimensional data. Sparse models have found widespread use in structure discovery, recovering data from corruptions, and a variety of large scale unsupervised and supervised learning problems. Assuming the availability of sufficient data, these methods infer dictionaries for sparse representations by optimizing for high-fidelity reconstruction. In most scenarios, the reconstruction quality is measured using the squared Euclidean distance, and efficient algorithms have been developed for both batch and online learning cases. However, new application domains motivate looking beyond conventional loss functions. For example, robust loss functions such as $\ell_1$ and Huber are useful in learning outlier-resilient models, and the quantile loss is beneficial in discovering structures that are the representative of a particular quantile. These new applications motivate our work in generalizing sparse learning to a broad class of convex loss functions. In particular, we consider the class of piecewise linear quadratic (PLQ) cost functions that includes Huber, as well as $\ell_1$, quantile, Vapnik, hinge loss, and smoothed variants of these penalties. We propose an algorithm to learn dictionaries and obtain sparse codes when the data reconstruction fidelity is measured using any smooth PLQ cost function. We provide convergence guarantees for the proposed algorithm, and demonstrate the convergence behavior using empirical experiments. Furthermore, we present three case studies that require the use of PLQ cost functions: (i) robust image modeling, (ii) tag refinement for image annotation and retrieval and (iii) computing empirical confidence limits for subspace clustering.
Automatic Inference of the Quantile Parameter
Karthikeyan Natesan Ramamurthy,Aleksandr Y. Aravkin,Jayaraman J. Thiagarajan
Statistics , 2015,
Abstract: Supervised learning is an active research area, with numerous applications in diverse fields such as data analytics, computer vision, speech and audio processing, and image understanding. In most cases, the loss functions used in machine learning assume symmetric noise models, and seek to estimate the unknown function parameters. However, loss functions such as quantile and quantile Huber generalize the symmetric $\ell_1$ and Huber losses to the asymmetric setting, for a fixed quantile parameter. In this paper, we propose to jointly infer the quantile parameter and the unknown function parameters, for the asymmetric quantile Huber and quantile losses. We explore various properties of the quantile Huber loss and implement a convexity certificate that can be used to check convexity in the quantile parameter. When the loss if convex with respect to the parameter of the function, we prove that it is biconvex in both the function and the quantile parameters, and propose an algorithm to jointly estimate these. Results with synthetic and real data demonstrate that the proposed approach can automatically recover the quantile parameter corresponding to the noise and also provide an improved recovery of function parameters. To illustrate the potential of the framework, we extend the gradient boosting machines with quantile losses to automatically estimate the quantile parameter at each iteration.
Pulse Skipping Modulated Buck Converter - Modeling and Simulation  [PDF]
Ramamurthy Srinivasan, Vanaja Ranjan P.
Circuits and Systems (CS) , 2010, DOI: 10.4236/cs.2010.12010
Abstract: Modeling and simulation results of a pulse skipping modulated buck converter for applications involving a source with widely varying voltage conditions with loads requiring constant voltage from full load down to no load is presented. The pulses applied to the switch are blocked or released on output voltage crossing a predetermined value. The regulator worked satisfactorily over a wide input voltage range with good transient response but with higher ripple content. Input current spectrum indicates a good EMI performance with crowding of components at audio frequency range for the se-lected switching frequency.
Case Series of Methylene Blue Injections for the Treatment of Zygapophysial and Sacroiliac Joint Pain: Results of 5 Cases  [PDF]
Jay Parekh,Maxim Eckmann,Somayaji Ramamurthy
Open Journal of Anesthesiology (OJAnes) , 2013, DOI: 10.4236/ojanes.2013.36066
Abstract: Introduction: Shealy is credited with the use of fluoroscopy guided radiofrequency ablation (RFA) for denervation of the lumbar zygapophysial (L-Z) joint in the mid-1970’s. Peng and colleagues described the use of methylene blue (MB) injection for discogenic pain; MB may work through direct neurotoxicity or inhibition of nitric oxide synthesis. We present a retrospective case series of five patients with L-Z or SI joint pain where MB used as an alternative to RFA. Materials and Methods: This is a retrospective case series of five patients who received MB for the chemical neurolysis of either medial or/and lateral branch’s for zygapophysial or SI joint pain. All of the MB blocks were done under fluoroscopic guidance and performed in the same manner as diagnostic medial and lateral branch blocks but with care to consider the medication as neurotoxic in relation to spinal nerves. On average 1cc of 0.05% final concentration MB was injected per nerve or sacral foraminal level. Results: Four of the five patients had significant lasting pain relief. Discussion: Chemical neurolysis has potential to achieve technical success in these refractory cases of spine pain possibly due to spread over a broader area; for this same reason the procedure should be performed carefully under fluoroscopic guidance.
Case Series of Methylene Blue Injections for the Treatment of Zygapophysial and Sacroiliac Joint Pain: Results of 5 Cases  [PDF]
Jay Parekh, Maxim Eckmann, Somayaji Ramamurthy
Open Journal of Anesthesiology (OJAnes) , 2013, DOI: 10.4236/ojanes.2013.36066
Abstract:

Introduction: Shealy is credited with the use of fluoroscopy guided radiofrequency ablation (RFA) for denervation of the lumbar zygapophysial (L-Z) joint in the mid-1970’s. Peng and colleagues described the use of methylene blue (MB) injection for discogenic pain; MB may work through direct neurotoxicity or inhibition of nitric oxide synthesis. We present a retrospective case series of five patients with L-Z or SI joint pain where MB used as an alternative to RFA. Materials and Methods: This is a retrospective case series of five patients who received MB for the chemical neurolysis of either medial or/and lateral branch’s for zygapophysial or SI joint pain. All of the MB blocks were done under fluoroscopic guidance and performed in the same manner as diagnostic medial and lateral branch blocks but with care to consider the medication as neurotoxic in relation to spinal nerves. On average 1cc of 0.05% final concentration MB was injected per nerve or sacral foraminal level. Results: Four of the five patients had significant lasting pain relief. Discussion: Chemical neurolysis has potential to achieve technical success in these refractory cases of spine pain possibly due to spread over a broader area; for this same reason the procedure should be performed carefully under fluoroscopic guidance.

Induced dusty flow due to normal oscillation of wavy wall
K. Kannan,V. Ramamurthy
International Journal of Mathematics and Mathematical Sciences , 2001, DOI: 10.1155/s0161171201005282
Abstract: A two-dimensional viscous dusty flow induced by normal oscillation of a wavy wall for moderately large Reynolds number is studied on the basis of boundary layer theory in the case where the thickness of the boundary layer is larger than the amplitude of the wavy wall. Solutions are obtained in terms of a series expansion with respect to small amplitude by a regular perturbation method. Graphs of velocity components, both for outer flow and inner flow for various values of mass concentration of dust particles are drawn. The inner and outer solutions are matched by the matching process. An interested application of present result to mechanical engineering may be the possibility of the fluid and dust transportation without an external pressure.
Applications of "Integrated Data Viewer'' (IDV) in the classroom
M. K. Ramamurthy
Advances in Geosciences (ADGEO) , 2006,
Abstract: A revolution is underway in the role played by cyberinfrastructure and modern data services in the conduct of research and education. We live in an era of an unprecedented data volume from diverse sources, multidisciplinary analysis and synthesis, and active, learner-centered education emphasis. Complex environmental problems such as global change and water cycle transcend disciplinary and geographic boundaries, and their solution requires integrated earth system science approaches. Contemporary education strategies recommend adopting an Earth system science approach for teaching the geosciences, employing pedagogical techniques such as enquiry-based learning. The resulting transformation in geoscience education and research creates new opportunities for advancement and poses many challenges. The success of the scientific enterprise depends heavily on the availability of a state-of-the-art, robust, and flexible cyberinfrastructure, and on the timely access to quality data, products, and tools to process, manage, analyze, integrate, publish, and visualize those data. Concomittantly, rapid advances in computing, communication, and information technologies have revolutionized the provision and use of data, tools and services. The profound consequences of Moore's Law and the explosive growth of the Internet are well known. On the other hand, how other technological trends have shaped the development of data services is less well understood. For example, the advent of digital libraries, web services, open standards and protocols have been important factors in shaping a new generation of cyberinfrastructure for solving key scientific and educational problems. This paper presents a broad overview of these issues, along with a survey of key information technology trends, and discuses how those trends are enabling new approaches to applying data services for solving geoscientific problems. Full Article in PDF (PDF, 182 KB) Citation: Ramamurthy, M. K.: A new generation of cyberinfrastructure and data services for earth system science education and research, Adv. Geosci., 8, 69-78, doi:10.5194/adgeo-8-69-2006, 2006. Bibtex EndNote Reference Manager XML
Some observation on visual function in 204 sellar lesions
Ramamurthy B,Kanaka T
Indian Journal of Ophthalmology , 1971,
Abstract:
Page 1 /50612
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.