50175 research outputs found
Sort by
Workspace of Multi-fingered Robotic Hands Using Monte Carlo Method
No full textMulti-fingered hands enable significantly enhanced manipulation capabilities to the robot where it is attached. As a consequence, analysis, design and development of multi-fingered hands has been of continuing interest in the robotics community. In this work, we propose a probabilistic Monte Carlo based approach to obtain the workspace of a well-known multi-fingered hand, the three-fingered Salisbury hand, modeled as a hybrid parallel manipulator. It is shown that Monte Carlo method can be used to obtain the volume of the well conditioned workspace of the hybrid manipulator in R-3 and SO(3). One of the obtained novel results is that with realistic constraints on the motion of the joints, the well-conditioned workspace of the hybrid manipulator is the largest when the grasped object area is approximately equal to the palm area. We also obtain and discuss the dependence of the workspace of the manipulator on it's geometry and other link and joint variables
In2Se3 Visible/Near-IR Photodetector With Observation of Band-Edge in Spectral Response
No full textWe report on the demonstration of visible/near-IR high-performance photodetector based on exfoliated beta-Indium selenide (In2Se3) on sapphire with a clear signature of band edge in spectral responsivity at a wavelength of similar to 850-900 nm. Room temperature photoluminescence (PL) measurements also indicated a peak at similar to 900 nm confirming the band-edge. Devices with inter-digitated metal-semiconductor-metal (MSM) geometry exhibited a responsivity of 3.8 A/W (normalized to device area). A low dark current of 0.80 nA and a photo to dark current ratio of similar to 52 were measured when illuminated with 650 nm A specific detectivity of 1 x 10(10) cm Hz(0.5) W-1 at 650 nm and 6 x 10(8) cm Hz(0.5) W-1 at the band-edge of 900 nm were estimated. These results indicate the promise of beta-(In2Se3) for visible/near-IR detector applications
Study of the long-term evolution of the accretion dynamics of GX 339-4
No full textWe study the dynamical behaviour of the galactic black hole source GX 339-4 during 2002-2011 outbursts using RXTE, Swift-XRT, XMM-Newton (PN) archival data. We present the spectral evolution of the source using four outburst data and discuss their similarities and differences between outbursts. We infer that the second peak in the 2002/03 and 2004/05 outbursts could be due to a second instant of triggered instability in the accretion disc due to irradiation from the central X-ray source after peak I. This propagates on a viscous time-scale and takes similar to 80-90 d after peak I to produce peak II. This unifies all four outbursts with a long rising time of similar to 90 d. The dynamical evolution of the accretion parameters has been studied by modelling the individual observed spectrum with a two-component accretion-disc model where a Keplerian accretion disc produces the soft photons and the hard part of the spectrum originates from a hot sub-Keplerian central corona. A generic mathematical model has been proposed to understand the evolution of accretion parameters for sources like GX 339-4 that have longer rising times. In addition, the possible differences in physical scenarios for outbursts with shorter rising times are also discussed
CONTRACTIVITY AND COMPLETE CONTRACTIVITY FOR FINITE DIMENSIONAL BANACH SPACES
No full textIt is known that if m >= 3 and B is any ball in C-m with respect to some norm, say parallel to.parallel to(B), then there exists a linear map L: (C-m,parallel to.parallel to(B)*) -> M-k which is contractive but not completely contractive. The characterization of those balls in C-2 for which contractive linear maps are always completely contractive, however, remains open. We answer this question for balls of the form Omega(A) in C-2 and the balls in their norm dual, where Omega(A) = { (z(1), z(2)) : parallel to z(1) A(1) + z(2)A(2)parallel to Op < 1} for some pair of 2 x 2 matrices A(1), A(2)
Cross-sectional study of factors influencing the residential water demand in Bangalore
No full textThe study investigates the influences of demographic and infrastructural covariates that drive the household water demand in the 198 municipal wards of Bangalore, India. In contrast to previous studies that rely on direct household income data, this study captures the household income effect on water demand with a set of proxy income covariates such as average built-up area, proportion of households in different income categories, per capita park area, population density, road infrastructure, etc. The macro-level demand study uses cross-sectional data comprising of dependent and independent variables of 198 municipal wards of Bangalore in the month of July 2015. Linear and non-linear demand models estimate the influence of factors using the ordinary least squares (OLS) method and results are compared. Results indicate that average built-up area, proportion of high income households and per capita park area positively influence the water demand while the number of members per household negatively influences water demand
Identifying and targeting the Achilles heel of drug resistant bacteria
No full textThe emergence of drug resistant strains of M.tuberculosis poses a major threat to public health, warranting urgent attention to the problem of tackling antimicrobial resistance. A number of studies have sought to understand the causes of drug resistance, and have led to the identification of several mechanisms including mutations in key targets, upregulation of drug efflux pumps, etc. Yet, there is no understanding of which mechanisms are operative in a given condition, whether microbes explore multiple mechanisms simultaneously, or if such mechanisms are influenced by each other and lead to alterations in the cell in a synchronized manner. Towards this, an understanding of the global mechanisms leading to resistance becomes necessary. This in turn will provide a basis to develop novel therapeutic strategies for tackling drug resistance.
To address this, we adopt a systems level analysis of the biomolecular networks associated with the emergence or sustenance of drug-resistant phenotypes, from which we decipher cellular alterations in an unbiased manner and identify emergent vulnerabilities in resistant bacilli. We integrate genomic, transcriptomic and phenotypic data from the model system M.smegmatis and generate an integrated genome-scale response network, and employ network-mining approaches to identify the highest differential activities operative in the drug-resistant strain. The corresponding proteins are seen to form a well-connected orchestrated subnet, providing insights into newly emerged vulnerabilities in the resistant bacilli. The networks suggest that multiple mechanisms are at play simultaneously to overcome the drug stress, of which response to oxidative stress predominates. Through targeted screening we discover that the resistant bacilli exhibit collateral sensitivity to several compounds that block antioxidant responses. We then test the shortlisted compounds against M. tuberculosis and three different drug-resistant clinical isolates and study the mechanistic basis of the efficacies of these compounds. Three of the tested compounds were able to reverse resistance in mycobacteria. One of the identified compounds shows high promise as a key component of a re-purposable drug combination for treating drug-resistant tuberculosis
Search for the production of (WWW -/+)-W-+/--W-+/- events at root s=13 TeV
No full textA search for the production of events containing three W bosons predicted by the standard model is reported. The search is based on a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS experiment at the CERN LHC and corresponding to a total integrated luminosity of 35.9 fb(-1). The search is performed in final states with three leptons (electrons or muons), or with two same-charge leptons plus two jets. The observed (expected) significance of the signal for (WWW -/+)-W-+/--W-+/- production is 0.60 (1.78) standard deviations, and the ratio of the measured signal yield to that expected from the standard model is 0.34(-0.34)(+0.62) . Limits are placed on three anomalous quartic gauge couplings and on the production of massive axionlike particles
Development of a solar reflector coating on AA6061 alloy by plasma electrolytic oxidation
No full textA spacecraft consists of various components which will function with maximum efficiency only when their operating temperature is maintained within certain specified ranges. Passive thermal control elements play an important role in maintaining the temperature of spacecraft components within the specified ranges by suitable selection of thermo-optical properties of the surfaces namely absorptance and emittance. Plasma electrolytic oxidation of AA 6061 is studied as a method to develop a solar reflector coating for space applications. The coatings are developed by making use of a silicate-based electrolyte. The influence of electrolyte composition, average current density, processing time, positive on-time and pulse frequency on the thermo-optical behaviour of the coating is studied. The thickness of the PEO coating is optimized so as to attain thermo-optical properties similar or better than conventional sulphuric acid anodizing. The optimized coating is subjected to adhesion and humidity tests as well as various space simulation tests such as thermal cycling and thermo-vacuum performance tests to evaluate the suitability of the coating as a thermal control surface for space application. Coatings obtained by PEO process and conventional sulphuric acid anodizing are further characterized using SEM, EDX, XPS, XRD and nanoprofilometry to have a comparative study of their morphology, microstructure and composition
Search for dark photons in decays of Higgs bosons produced in association with Z bosons in proton-proton collisions at root s=13 TeV
No full textA search is presented for a Higgs boson that is produced in association with a Z boson and that decays to an undetected particle together with an isolated photon. The search is performed by the CMS Collaboration at the Large Hadron Collider using a data set corresponding to an integrated luminosity of 137 fb(-1) recorded at a center-of-mass energy of 13 TeV. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for associated Higgs and Z boson production and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a mass of 125 GeV, assuming the standard model production cross section, this corresponds to an observed (expected) upper limit on this branching fraction of 4.6 (3.6)% at 95% confidence level. These are the first limits on Higgs boson decays to final states that include an undetected massless dark photon
Dynamics of physiologically relevant noncanonical DNA structures: an overview from experimental and theoretical studies
No full textDNA is a complex molecule with phenomenal inherent plasticity and the ability to form different hydrogen bonding patterns of varying stabilities. These properties enable DNA to attain a variety of structural and conformational polymorphic forms. Structurally, DNA can exist in single-stranded form or as higher-order structures, which include the canonical double helix as well as the noncanonical duplex, triplex and quadruplex species. Each of these structural forms in turn encompasses an ensemble of dynamically heterogeneous conformers depending on the sequence composition and environmental context. In vivo, the widely populated canonical B-DNA attains these noncanonical polymorphs during important cellular processes. While several investigations have focused on the structure of these noncanonical DNA, studying their dynamics has remained nontrivial. Here, we outline findings from some recent advanced experimental and molecular simulation techniques that have significantly contributed toward understanding the complex dynamics of physiologically relevant noncanonical forms of DNA