883 research outputs found

    Level Set Jet Schemes for Stiff Advection Equations: The SemiJet Method

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    Many interfacial phenomena in physical and biological systems are dominated by high order geometric quantities such as curvature. Here a semi-implicit method is combined with a level set jet scheme to handle stiff nonlinear advection problems. The new method offers an improvement over the semi-implicit gradient augmented level set method previously introduced by requiring only one smoothing step when updating the level set jet function while still preserving the underlying methods higher accuracy. Sample results demonstrate that accuracy is not sacrificed while strict time step restrictions can be avoided

    Buckling Analysis of Composite Hexagonal Lattice Cylindrical Shell using Smeared Stiffener Model

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    Hexagonal lattice pattern formed by helical and circumferential ribs is the most common among different possible lattice patterns. An energy-based smeared stiffener model (SSM) is developed to obtain equivalent stiffness coefficients of a composite lattice cylindrical shell with such hexagonal lattice patterns. Using the equivalent stiffness coefficients, Ritz buckling analysis was carried out. Extensive finite element modelling covering different representative sizes have been carried out. SSM is validated by comparing the estimated buckling loads. Variation of material properties of rib unidirectional composites from those of normal unidirectional composites is accounted for in the energy  formulations.Defence Science Journal, 2009, 59(3), pp.230-238, DOI:http://dx.doi.org/10.14429/dsj.59.151

    Phytochemical constituents of Cadaba Trifoliata Roxb. root extract

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    Cadaba trifoliata Roxb is belongs to the family Capparaceae, important medicinal plant of Indian medicinal plants. The methanol, ethanol, ethyl acetate and aqueous extracts along with dry powder of root were screened for the presence of phytochemicals. The phytochemical constituents were analyzed by qualitative and GC-MS method. Preliminary studies showed that the presence of Tannins, Steroids, Alkaloids, Glycosides, Flavonoids and Phenolic compounds. In the GC-MS analysis, 17 bioactive phytochemical compounds were identified in the alcoholic extract. The identification of phytochemical compounds in very high peak area, 1, 2-Benzenedicarboxylic acid, diisooctyl ester (C24H38O4) with RT 24.95 has peak area 51.86% and 1-Methyl-pyrrolidine-2-carboxylic acid (C6H11NO2) with RT 6.89 has peak area 20.58%. The main important compound phytol (C20H40O) with RT 18.95 ranks with peak area 1.21%. A nature compound contains diterpene activity anti-cancer, anti-diabetic, anti-inflammatory, anti-oxidant activity and antimicrobial activity.Keywords:- Cadaba trifoliata, phytochemical constituents, alcoholic root extracts

    Green Entrepreneurs Challenges and Innovation: The Struggles They Face

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    Purpose:  A green entrepreneur's enterprise prioritises environmental protection by minimising the negative impact of existing products, services, or processes. It contributes to the beneficial transformation of society. This study discusses green entrepreneur challenges and innovations in Tamil Nadu's Salem District.  The intention of this study is to determine what factors determine the obstacles they experience in their business and how to transform those obstacles into opportunities   Design/methodology/approach:  Snowball sampling is employed to choose the population for this study from Salem's vast population, and the total number of respondents chosen is 50.   Findings: Simple Percentage Analysis, Chi-Square, and the Henry Garrett Ranking Method are utilised for measuring the factors. The result of testing the hypothesis indicates that there is no correlation between age and the influence to start a business using technical or professional knowledge and skill   Future Implications: Our work presents a range of theoretical and practical implications, as previously said, but it is not without limitations. In order to ascertain the direct and indirect effects of stakeholder demands, green dynamic capacity, green innovation, and firm performance, we first propose that future research make use of our framework and conduct a comparison study of small and large enterprise

    1-Methyl-3-(2-methyl­phen­yl)-3a-nitro-1,2,3,3a,4,9b-hexa­hydro­chromeno[4,3-b]pyrrole

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    The asymmetric unit of the title compound, C19H20N2O3, contains two independent mol­ecules in both of which the pyrrolidine ring adopts an envelope conformation, but with a C atom as the flap in one mol­ecule and the N atom in the other. The pyran ring adopts a half-chair conformation in both mol­ecules. In the crystal, mol­ecules are linked via C—H⋯O hydrogen bonds and C—H⋯π inter­actions

    Projector Light Control And Fuzzy Based Control For EDOC In Electric Vehicle For Two Wheelers

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    Projector light control mainly focus on the battery management in an e-vehicle. This provides a long time journey without any unnecessary wastage of the battery. This may be used in all sort of e-vehicle. The system can replace the hardware components of the Electric vehicles in Two wheelers and does not need extra equipment. The size and volume EDOC is reducedTo control electric drive onboard converter (EDOC) using Fuzzy in the DC (battery) side. To automate the projector light in an E-vehicle for two wheeler to reduce the battery consumptio

    Design of an Intelligent Controller for Armature Controlled DC Motor using Fuzzy Logic Technique

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    This paper presents a fuzzy control approach to the speed control of DC shunt motor using armature control. This paper presents concept of development of conventional controller and the design of a fuzzy logic controller applicable to DC Motor Speed Control System (MSCS) with high performance of the FL controller. Since armature voltage supply has a major influence in controlling speed, therefore one of the inputs to the proposed FL Controller will be actual armature voltage supply (Va) while another input will be error (e) in speed. The transfer function model of the DC shunt motor has been obtained via experimentation and calculations and simulated and then as per requirement and specification, the proposed fuzzy logic controller has been designed and simulated using Fuzzy Logic and Simulink Toolboxes of MATLAB 7. Results show robustness against changing loading conditions

    Effect of Helical Winding Angle on External Pressure based Buckling of Partially Filled Thin Composite Cylindrical Shells

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    Effect of helical winding angle on buckling load of thin composite tubes is investigated in this work.  Experiments are conducted on both empty and partially filled S2 glass tubes to estimate contribution of strength to the tubes by the filler material.  Chosen filler material mechanically simulates behavior of typical solid propellant used in aerospace application.   FE analysis with non-linear effect correlates well with the experimental data.  Three series of experiments are conducted to quantify effect of helical winding angle and increase in volumetric loading fraction(VLF).  Results confirm appreciable improvement in strength of filled tubes for higher VLF.  For the chosen pattern of winding, lower winding angle provides more strength to the tubes against external pressure buckling.  &nbsp

    2-Amino­pyridinium picrate

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    In the title compound, C5H7N2 +·C6H2N3O7 −, there are two crystallographically independent cations and anions (A and B) in the asymmetric unit. In both picrate anions, one of the nitro groups lies in the plane of the benzene ring [r.m.s. deviations = 0.014 (2) and 0.014 (2) Å for anions A and B, respectively] and the other two are twisted away by 39.0 (2) and 18.8 (2)° in A, and 18.2 (1) and 2.5 (2)° in B. In the crystal, the cations and anions are linked by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds, forming a two-dimensional network

    2-(1,2,3,4-Tetra­hydro-9H-carbazol-1-yl­idene)propane­dinitrile

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    In the title compound, C15H11N3, the cyclo­hexene ring adopts a sofa conformation. An intra­molecular N—H⋯N hydrogen bond generates an S(7) ring motif. In the crystal, mol­ecules are linked by inter­molecular N—H⋯N, C—H⋯N and C—H⋯π inter­actions into a three-dimensional network
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