421 research outputs found

    Postbuckling Behaviour of Anisotropic Laminated Composite Plates due to Shear Loading

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    This study investigates postbuckling behaviour of laminated composite plates using a nine-noded shear flexible quadrilateral plate element. The formulation includes nonlinear strain-displacement relation based on von Karman's assumption. The nonlinear governing equations are solved through iteration. A detailed parametric study is carried out to bring out the influence of ply-angle, aspect ratio and material properties on the postbuckling strength of laminates due to in-plane shear loads

    Lunar base habitat designs: Characterizing the environment, and selecting habitat designs for future trade-offs

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    A survey of distinct conceptual lunar habitat designs covering the pre- and post-Apollo era is presented. The impact of the significant lunar environmental challenges such as temperature, atmosphere, radiation, soil properties, meteorites, and seismic activity on the habitat design parameters are outlined. Over twenty habitat designs were identified and classified according to mission type, crew size; total duration of stay, modularity, environmental protection measures, and emplacement. Simple selection criteria of (1) post-Apollo design, (2) uniqueness of the habitat design, (3) level of thoroughness in design layout, (4) habitat dimensions are provided, and (5) materials of construction for the habitat shell are specified, are used to select five habitats for future trade studies. Habitat emplacement scenarios are created to examine the possible impact of emplacement of the habitat in different locations, such as lunar poles vs. equatorial, above ground vs. below ground, etc

    Graph Based Texture Pattern Classification

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    Penetration of Projectiles in Composite Laminates

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    This paper deals with the prediction of the penetration phenomenon of a cylindro-conical impactor on the ke;labepoxy-laminated composites using C eight-nded serendipity q&drilateral finite elementbased on first-order shear deformation theory (FSDT). Local as well as global deformations during impact is considered in the evaluation of indentation, penetration, and perforation phases. Local strainsduring impact have been evaluated using the hypothesis made from the available experimental observations of bulging during penetration. A detailed parametric study, considering various projectilesand target plate variables, has been carried out to find their effect on the response of the plate, and ballistic parameters, such as ballistic limit and absorbed energy

    Chemotherapy of malaria. Part VIII. Synthesis of uracils, thiouracils, pteridines and thiopteridines

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    Twenty-two pteridines of formula (I) and twenty-one thiopteridines of formula (II) have been synthesisedvia 4-aminouracils and 4:5-diaminouracils for assessing their antimalarial and antibacterial properties

    Influence of anti-epileptic drugs on hematological and biochemical parameters in patients with epilepsy

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    Background: Epilepsy is a chronic neurological condition which may require long-term treatment with antiepileptic drugs (AEDs). The challenge in AED management is to attain freedom from seizures, without side-effects and with good quality-of-life. However, AEDs are reported to induce potential adverse effects, which can remain unnoticed over long time. In this regard, earlier studies report inconsistent results in hematological and biochemical toxicity of AEDs. The objective of the present study was to evaluate the effects of AED monotherapy and polytherapy on hematological and biochemical parameters.Methods: This was a cross-sectional, observational study carried out among patients with epilepsy (PWE) receiving AEDs. The data on baseline demographic characteristics, treatment, adverse drug reactions, hematological, and biochemical investigations were collected. Statistical analysis was performed using the SPSS version 18 and descriptive statistics such as mean and median were used to summarize the data and inferential tests like Chi-square was used to compare categorical variables between groups.Results: There were 255 PWE in mean age range of 28.68±9.29 years, with 56.54% males. A total of 78.04% had focal, 18.04% had generalized seizures and remaining 3.92% were unclassified. Majority of (55.69%) PWE received polytherapy with AEDs. Females had significantly lower levels of hemoglobin (Hb) when compared with males (p=0.000), and patients on AED polytherapy showed significant difference in low Hb (p=0.006) and high alkaline phosphatase (ALP) levels (p=0.001).Conclusions: The results of this study showed significant alterations in the levels of Hb and ALP with the use of AED polytherapy in PWE. Routine hematological and biochemical investigations may be considered during AED treatment in those patients receiving AED polytherapy

    Life support systems analysis and technical trades for a lunar outpost

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    The NASA/JPL life support systems analysis (LISSA) software tool was used to perform life support system analysis and technology trades for a Lunar Outpost. The life support system was modeled using a chemical process simulation program on a steady-state, one-person, daily basis. Inputs to the LiSSA model include metabolic balance load data, hygiene load data, technology selection, process operational assumptions and mission parameter assumptions. A baseline set of technologies has been used against which comparisons have been made by running twenty-two cases with technology substitutions. System, subsystem, and technology weights and powers are compared for a crew of 4 and missions of 90 and 600 days. By assigning a weight value to power, equivalent system weights are compared. Several less-developed technologies show potential advantages over the baseline. Solid waste treatment technologies show weight and power disadvantages but one could have benefits associated with the reduction of hazardous wastes and very long missions. Technology development towards reducing the weight of resupplies and lighter materials of construction was recommended. It was also recommended that as technologies are funded for development, contractors should be required to generate and report data useful for quantitative technology comparisons

    Offshore Wind Feasibility Study in India

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    Offshore wind provides a scalable alternative to conventional energy resources. This chapter provides an insight into various activities of Ministry of Earth Sciences for the realization of offshore wind in India. To understand the hurdles in policy frame work for offshore wind, the evolution of onshore wind policy is analyzed and suitable strategies for offshore wind are proposed. Wind resource assessment results indicated a high offshore potential at Kanyakumari, Rameshwaram, Gulf of Khambhat, and Gulf of Kutch. Commercial viability studies showed levelized cost of electricity (LCOE) of around Rs 10/kWh at identified sites for an internal rate of return (IRR) of 14%. Offshore light detection and ranging (LiDAR)-based data collection platform has been installed at Gulf of Khambhat and Kutch to obtain bankable wind data for the development of offshore wind farms. A preliminary design of substructure by exploring different concepts like monopile, jacket, and gravity-based foundations was carried out based on their suitability for site-specific environmental and soil data. The port facilities along Gujarat and Tamil Nadu coast were assessed, and installation methodology was developed considering marine spread along the Indian coast

    Free-vibration Characteristics of Laminated Angle-ply Non-circular Cylindrical Shells

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    This paper deals with the free-vibration behaviour of anisotropic laminated angle-ply noncircular cylindrical shells using finite element approach. The formulation is based on first-ordershear deformation theory. The present model accounts for in-plane and rotary inertia effects. A detailed study has been carried out to highlight the effects of shell geometry, cross-sectionalproperties, lay-up and ply-angles on the natural frequencies of different types of modes of vibration of non-circular elliptical shell structures
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