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Prakash R. Apte

Bio: Prakash R. Apte is an academic researcher from Indian Institute of Technology Bombay. The author has contributed to research in topics: Taguchi methods & Threshold voltage. The author has an hindex of 7, co-authored 48 publications receiving 166 citations. Previous affiliations of Prakash R. Apte include Indian Institutes of Technology & Datta Meghe College of Engineering.

Papers
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Journal ArticleDOI
01 Jan 2016-Silicon
TL;DR: In this article, the authors report the design, fabrication and characterization of electrically tunable, bulk micro machined, doubly clamped, circular cross-section flexure based square-plate MOSO-based micro-mirrors for different frequencies starting from 1 kilohertz to 172 kiloherstz on silicon {100} oriented wafers with high Q factors in the air.
Abstract: We report the design, fabrication and characterization of electrically tunable, bulk micro machined, doubly clamped, circular cross-section flexure based square-plate Metal-On-Oxide, DC bias tension applied, resonant micro-mirrors for different frequencies starting from 1 kilohertz to 172 kilohertz on silicon {100} oriented wafers with high Q factors in the air, that have high resilience. Though silicon shows inherent reflective behavior, the surface quality of the top-deposited metal layer is treatment specific. The sputtered chrome-gold films have good light scattering properties, for precise measurements within 6 ×6 ROI matrixes for vibrometry and AFM. We introduce novel circular cross-section flexure hinges with the advantages of compact design, 5 fold better precision of rotation compared to similar constant cross-section flexure, lesser stiffness, and beam length and beam width that are less decisive for the micro-manufacture. We have fabricated the device, with a double mask, replacing torsion beams with flexure beams. These suspended-in-air-in-trapezoidal-cavity square plate micro-mirrors fabricated on the silicon {100} oriented wafers, are electrically tunable at ±30 Volts, with onset of motion at as low as 3 Volts electrical potential, with the largest achieved tilt angle as high as 11 degrees and parabolic capacitance-voltage characteristics, that confirm the motion of the device in a cavity. The motion of these devices was recorded as a Doppler frequency shift. The result shows a slight improvement in mirror surface quality when resonant micro-mirrors are applied with bias tension, that deviates from the results presented in prior art. The micro-mirrors initially show inactivity in motion, which was stabilizes later. The exact mechanism responsible for this initial inactivity is not known, we attribute it to the sluggish behavior of joined mechanical elements with large time constants, which slow down the vibrancy.

2 citations

Journal ArticleDOI
TL;DR: In this paper, nanoclay and multi-wall carbon nanotubes have been used as a dual filler in an epoxy matrix, which achieved 57% improvement in tensile strength.
Abstract: In this study, nanoclay and multi-wall carbon nanotubes have been used as a dual filler in an epoxy matrix. In the design of the experiment (DOE) the Taguchi Method was selected to study the effect of the factors involved in this study. The effect of the clay/MWNT ratio, types of solvent, clay cation, composition of LENR, cure time and cure temperature on tensile properties of the epoxy nanocomposites were investigated. The confirmation experiment obtained from Taguchi analysis, achieved 57% improvement in tensile strength. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the presence of intercalated and aggregated structures. Due to the lower crosslink density of the system, a decrease in decomposition temperature and glass transition temperature was observed in the optimum sample.

2 citations

Proceedings ArticleDOI
01 Nov 2009
TL;DR: In this article, Taguchi's method for design of experiments to test market splitting algorithm of an electric power exchange is proposed, which is required because price-volume pairs of a trader are usually bound by confidentiality requirement and hence not available as test data.
Abstract: This paper proposes Taguchi's method for design of experiments to test market splitting algorithm of an electric power exchange. Such a mechanism is required because price-volume pairs of a trader are usually bound by confidentiality requirement and hence not available as test data. We also propose a novel and simple market splitting heuristic considering congestion management problem in a meshed network with incomplete information of the network. Simulation results are reported in the paper.

2 citations

Proceedings ArticleDOI
09 Jul 2012
TL;DR: In this article, the effect of oxygen partial pressure on the structural and fatigue properties of Bismuth ferrite (BiFeO 3 ) thin film was studied and it has been found that polarization of thin film is very sensitive to the partial pressure.
Abstract: Bismuth ferrite (BiFeO 3 ) is a potential candidate for future generation of FeRAM due to its large polarization with additional advantage of being lead free. La and Mn doped BiFeO 3 (BLFMO) thin films were deposited by pulsed laser deposition. Effect of oxygen partial pressure on the structural and fatigue properties were studied. It has been found that polarization of thin film is very sensitive to the oxygen partial pressure. The leakage current density found to be in the order of 10−7 A/cm2 at 200kV/cm. Ferroelectric polarization is 73 μC/cm2 and coercive field is 200kV/cm. Fatigue endurance test of BLFMO thin film at 500kV/cm shows films almost fatigue free after 108 pulses. Retention test also carried out and found that there is only 3% change in the polarization up to 105 seconds, thereby making BFO a promising candidate for memory applications.

1 citations

Proceedings ArticleDOI
22 Jan 2005
TL;DR: In this paper, the authors proposed a two-fold separation technique, porous filter for fractionating strands on size and final run through microchannels (agarose, buffer solution) viscous enough for DNA electrophoresis.
Abstract: Conventional DNA separation procedures involve large sizes, high voltages and are unfit for large molecules. Proposed set-up constitutes two fold separation techniques, porous filter for fractionating strands on size and final run through microchannels (agarose, buffer solution) viscous enough for DNA electrophoresis. For arriving at the final set-up all the physical contradictions like voltage, viscosity of the fluid, length of the channel were analyzed. The physical set up consists around 20 microchannels (varying diameters) positioned at 500um (centre-to-centre spacing) assembling entire device within 1cm. Polymerase Chain Reaction (PCR) treated DNA assays, are fed to microchannel entrances. Mixture of DNA strands are then passed through magnetic filters. Filtering property of the filters is adjusted by regulating corresponding magnetic field strengths. Smallest strands pass through small pored filter, owing to high velocity (in electrophoresis), thus categorization being done. Proposal replaces conventional apparatus by miniaturized equipment, in ideal case disposable. Miniaturization reduced voltages requirement, solving high-voltage handling problems. Proposed apparatus can fractionate large (>200kbp) molecules and even organic molecules. Key Words: microchannel, multi-channel, electrophoresis, miniaturization, DNA separation 1. INTRODUCTION DNA array technologies provide rapid and cost-effective methods of identifying genetic variations and gene expressions. DNA separation has a growing importance in numerous applications in biotechnology, medicine and chemistry. Wealth of available DNA sequence data makes it possible to identify many diseases as well as biological threats such as the presence of infectious agents in the environment. Alterations in gene expression patterns or in a DNA sequence can seriously affect biological functions. Miniatur izing the process could decrease the cost and timescale of gene sequencing. Microfabricated bioanalytical devices are very efficient platforms for simultaneous analysis of biologically important molecules; and they offer great potential for sensitive and large-scale DNA analysis. Efforts to improve DNA separation in microdevices have led to advances in capillary electrophoresis and the development of novel separation strategies. Microfluidics focused on the development of separation matrices with low injection viscosities has been recently developing. Small sample volumes and increased separation speed have made microscale separation strategies the focus of current research. The sequencing of genomes requires analysis of a wider range of DNA fragments, therefore, research will focus on methods for designing tunable sieving matrices or devices with tunable pore size

1 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: Evidence evaluating these supplements in CO VID-19 patients is lacking, and providers and patients should not rely on dietary supplements to prevent or treat COVID-19, rather, reference to evidence-based guidelines should guide treatment decisions.
Abstract: News and social media platforms have implicated dietary supplements in the treatment and prevention of coronavirus disease 2019 (COVID-19). During this pandemic when information quickly evolves in the presence of contradicting messages and misinformation, the role of the pharmacist is essential. Here, we review theoretical mechanisms and evidence related to efficacy and safety of select supplements in the setting of COVID-19, including vitamin C, vitamin D, zinc, elderberry, and silver. Evidence evaluating these supplements in COVID-19 patients is lacking, and providers and patients should not rely on dietary supplements to prevent or treat COVID-19. Rather, reference to evidence-based guidelines should guide treatment decisions.

104 citations

Journal ArticleDOI
TL;DR: In this article, a least error squares (LES) filter is used to estimate the phasor parameters of the CT secondary current and a new minimum estimation error tracking approach is proposed to enhance the precision of the estimation.
Abstract: A current transformer (CT) is accurately modeled for representation of the CT saturation effects on digital protective relays. Simulation studies performed in the PSCAD/EMTDC platform are used to investigate the impacts of CT saturation on the current phasor estimation. A new algorithm is also proposed for detection and compensation of CT saturation effects, based on: a least error squares (LES) filter which estimates the phasor parameters of the CT secondary current; a novel saturation detection method which uses the output of the LES filter for saturation detection; and a new minimum estimation error tracking approach which enhances the precision of the phasor estimation. The proposed saturation detection/compensation algorithm is independent of the parameters of the CT, the burden, and the power system. The study results show that the proposed algorithm: 1) reconstructs the distorted current waveform, under dc and ac saturation conditions, with the required precision and speed and 2) performs satisfactorily under inductive burden and under deep and slight saturation conditions.

75 citations

Proceedings ArticleDOI
14 Oct 2017
TL;DR: This paper presents the first automated system-level analysis of multicore CPUs based on ARMv8 64-bit architecture when pushed to operate in scaled voltage conditions and proposes a new composite metric (severity) that aggregates the behavior of cores when undervolted and can support system operation and design protection decisions.
Abstract: In this paper, we present the first automated system-level analysis of multicore CPUs based on ARMv8 64-bit architecture (8-core, 28nm X-Gene 2 micro-server by AppliedMicro) when pushed to operate in scaled voltage conditions. We report detailed system-level effects including SDCs, corrected/uncorrected errors and application/system crashes. Our study reveals large voltage margins (that can be harnessed for energy savings) and also large $V_{min}$ variation among the 8 cores of the CPU chip, among 3 different chips (a nominal rated and two sigma chips), and among different benchmarks.Apart from the $V_{min}$ analysis we propose a new composite metric (severity) that aggregates the behavior of cores when undervolted and can support system operation and design protection decisions. Our undervolting characterization findings are the first reported analysis for an enterprise class 64-bit ARMv8 platform and we highlight key differences with previous studies on x86 platforms. We utilize the results of the system characterization along with performance counters information to measure the accuracy of prediction models for the behavior of benchmarks running in particular cores. Finally, we discuss how the detailed characterization and the prediction results can be effectively used to support design and system software decisions to harness voltage margins for energy efficiency while preserving operation correctness. Our findings show that, on average, 19.4% energy saving can be achieved without compromising the performance, while with 25% performance reduction, the energy saving raises to 38.8%.CCS CONCEPTS• Hardware → Power and energy → Power estimation and optimization; • Hardware → Robustness → Hardware reliability → Process, voltage and temperature variations

59 citations

Journal ArticleDOI
TL;DR: In this paper, the results of the preliminary results were linearized by Langmuir's and Freudlich's models and the thermodynamic parameters, such as,,, and, were also evaluated.
Abstract: Residues from the processing of cassava roots (Manihot esculenta Crantz), or cassava peels, are evaluated as chemically modified adsorbents with H2O2, H2SO4, and NaOH, in the removal of metal ions Cd(II), Pb(II), and Cr(III) from contaminated water. Modified adsorbents were chemically characterized for their chemical composition and (point of zero charge), while adsorption tests determined the best conditions of pH, adsorbent mass, and contact time between adsorbent and adsorbate in the process of removal of the metal ions. Isotherms obtained from the preliminary results were linearized by Langmuir’s and Freudlich’s models. The thermodynamic parameters, such as , , and , were also evaluated. The modifying solutions proposed were effective in the modification of adsorbents and resulted in high capacity sorption materials. Equilibrium time between adsorbent and adsorbate for the solutions contaminated with metals is about 40 minutes. The Langmuir model adjusted to most results, indicating monolayers adsorption of Cd(II), Pb(II), and Cr(III). The values obtained for Langmuir show a higher adsorption capacity caused by chemical modifications, with values such as 19.54 mg Cd(II) per g of M. NaOH, 42.46 mg of Pb(II) per g of M. NaOH, and 43.97 mg of Cr(III) per g of M H2O2. Results showed that modified cassava peels are excellent adsorbent, renewable, high availability, and low-cost materials and a feasible alternative in the removal of metals in industries.

51 citations