3,628 research outputs found

    Application of Genetic Algorithm Technique for Machining Parameters Optimization in Drilling of Stainless Steel

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    Abstract This work is aimed at developing relations between the pertinent variables that affect drilling process of stainless steel using artificial neural network. The experiments were conducted on vertical CNC machining centre. The parameters used were spindle speed and feed rate. The effect of machining parameters on entry burr height, exit burr height and surface roughness was experimentally evaluated for different spindle speeds and feed rates. A model was established between the drilling parameters and experimentally obtained data using ANN. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the burr height and surface roughness in drilling of stainless steel. Genetic algorithm (GA) technique was used in this work to identify the optimized drilling parameters. Confirmation test was conducted with the optimized parameters and it was found that confirmation test results were similar to that of GA-predicted output values

    First record of Parapercis clathrata (Perciformes: Pinguipedidae) from Indian waters

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    A single specimen of latticed sandperch, Parapercis clathrata measuring 163 mm total lenth was caught in a trawler off Tuticorin, south-east coast of India in February 2010. Morphometric and meristic characters of the recorded specimen are described. This record constitutes the first occurrence of the species in Indian waters and a substantial westward extension of its known geographical distribution

    Polygon Shaped 3G Mobile Band Antennas for High Tech Military Uniforms

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    Smart Textiles integrated with communicating components have been used in military for many applications. Wearable antenna can be attached or embedded into smart textiles which could be used for communication between combat soldiers in the battlefield. This paper presents the design of three different polygon shaped patch antenna operating on 3G Mobile Band frequency 2100 MHz embedded on three different dielectric constant materials for Military applications. The proposed polygon shaped patch antenna introduces horizontal slit in its patch to improve the antenna performance. The effect of slit length and slit width on the antenna performance is analyzed. &nbsp

    Trend analysis and variability of satellite-based soil moisture data for the Lower Bhavani basin, Tamil Nadu using Google Earth Engine

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    Soil moisture is a significant hydrological component that is dynamic in nature. The variation in soil moisture in the basin scale would affect the vegetation, ecology and environment. Soil moisture trend analysis aids in providing the variation of soil moisture over the basin. The present study aimed to analyse the soil moisture trend in Lower Bhavani basin, Tamil Nadu from 2003-2022. Satellite-based soil moisture Global Land Data Assimilation System (GLDAS) data was extracted from the Google Earth Engine (GEE) platform to analyse the variation and trend over the period of time. The highest and lowest soil moisture was observed during monsoon and summer months and its percentage variation was studied. Using Man-Kendall test and Sen’s slope, trend analysis was calculated for two decades (2003-2012 and 2013-2022). In 2003-2012, an increasing trend of soil moisture was observed during winter (October to February); from 2013-2022, an increasing trend was observed during both winter (October to February) and monsoon seasons (June to September). The remaining season did not follow any trend, and there was no decreasing trend in soil moisture. The trend analysis of the study will help to monitor and manage the environmental system across the Lower Bhavani basin

    Optimal Principal Component Analysis in Distributed and Streaming Models

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    We study the Principal Component Analysis (PCA) problem in the distributed and streaming models of computation. Given a matrix ARm×n,A \in R^{m \times n}, a rank parameter k<rank(A)k < rank(A), and an accuracy parameter 0<ϵ<10 < \epsilon < 1, we want to output an m×km \times k orthonormal matrix UU for which AUUTAF2(1+ϵ)AAkF2, || A - U U^T A ||_F^2 \le \left(1 + \epsilon \right) \cdot || A - A_k||_F^2, where AkRm×nA_k \in R^{m \times n} is the best rank-kk approximation to AA. This paper provides improved algorithms for distributed PCA and streaming PCA.Comment: STOC2016 full versio

    Effectiveness of a treadmill-based aerobic exercise intervention on pain, daily functioning, and quality of life in women with primary dysmenorrhea: a randomized controlled trial

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    Objective: To evaluate the effectiveness of a treadmill-based aerobic exercise intervention on pain and associated symptoms of primary dysmenorrhea. Methods: Seventy women with primary dysmenorrhea were included in the study. The experimental group underwent supervised aerobic training for 4 weeks followed by unsupervised home exercise for the next 6 months. The control group continued usual care. The primary outcome was pain. Secondary outcomes included quality of life (QoL), daily functioning, and sleep. Results: After the 4-week training, compared to the control group exercise significantly improved primary outcomes pain quality (mean difference (MD) -1.9, 95% CI 3.8 to -0.04, p < 0.05), and intensity (MD -4.7, 95% CI -9.3 to -0.09, p < 0.05), but not present pain. Significant effects were also reported for pain interference (MD -1.7, 95% CI -3.4 to -0.02, p < 0.05) at 4 weeks; the other outcomes did not significantly differ between groups at this time. During the follow-up period of 7-months, the effect on pain improved to 22 mm (95% CI 18 to 25). Significant benefits of exercise were maintained up to 7-months for present pain, QoL and daily functioning. Conclusion: Exercise has significant effects on primary dysmenorrhea-related pain, QoL and function

    Nanomaterials based Decontamination Formulation for use in Personal Decontamination Kit Against Chemical Warfare Agents

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    Present paper relates to nanomaterials based decontamination formulation made up of TiO2, MgO, and ZnO nanoparticles for the use against chemical warfare agents. This decontamination formulation was prepared by mixing 90 per cent of TiO2 nanoparticles of 5-15 nm size range, 8 per cent of MgO nanoparticles of 5-15 nm size range, and 2 per cent of ZnO nanoparticles of 20-30 nm size range. Prepared formulation exhibited 98-99 per cent of physical removal efficiency against contaminated glass, rubber, painted metal, metal surfaces. It efficiently removed chemical warfare agents from contaminated skin thus ameliorating chances of fatality which is expected due to skin penetrated chemical warfare agents. It also chemically degraded 97 per cent of sulphur mustard in 24 h, 99.9 per cent of sarin in 2 h, respectively unlike Fuller’s earth which chemically degraded only 63 per cent of sulphur mustard and 59 per cent of sarin in 24 h

    Shear Alignment and Instability of Smectic Phases

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    We consider the shear flow of well-aligned one-component smectic phases, such as thermotropic smectics and lamellar diblock copolymers, below the critical region. We show that, as a result of thermal fluctuations of the layers, parallel (cc) alignment is generically unstable and perpendicular (aa) alignment is stable against long-wavelength undulations. We also find, surprisingly, that both aa and cc are stable for a narrow window of values for the anisotropic viscosity.Comment: To appear in PRL. Revtex, 1 figure
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