10,681 research outputs found

    The solar wind velocity and its correlation with geomagnetic, solar and cosmic ray activity

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    Correlation of plasma velocity with indices of solar and terrestrial activity - cosmic radiatio

    (Anti)symmetric multivariate trigonometric functions and corresponding Fourier transforms

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    Four families of special functions, depending on n variables, are studied. We call them symmetric and antisymmetric multivariate sine and cosine functions. They are given as determinants or antideterminants of matrices, whose matrix elements are sine or cosine functions of one variable each. These functions are eigenfunctions of the Laplace operator, satisfying specific conditions at the boundary of a certain domain F of the n-dimensional Euclidean space. Discrete and continuous orthogonality on F of the functions within each family, allows one to introduce symmetrized and antisymmetrized multivariate Fourier-like transforms, involving the symmetric and antisymmetric multivariate sine and cosine functions.Comment: 25 pages, no figures; LaTaX; corrected typo

    NVA: A Value Addition Measure For Capital Project Evaluation

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    Corporate financial objective of stockholder wealth maximization and use of discounted cash flow methods for evaluation of capital projects are two of the well-accepted tenets of financial management. Present project evaluation methods, including the Net Present Value (NPV) technique, do not fully meet the stockholder wealth maximization criteria. This paper attempts to scrutinize the relevance of the NPV method in achieving the wealth maximization objective and suggests an alternative value addition measure, named Net Value Added (NVA). In the NPV method, all cash flows pertaining to a project are lumped together and discounted with one single rate, the weighted average cost of capital. The NVA method advocates that a project’s residual (net of its debt servicing) cash flows that belong to stockholders should be classified on the basis of their end-use, viz., equity servicing, capital maintenance, and value creating surplus cash flows.  As the risks associated with each of these three stockholders’ cash flows are not the same, they are separately discounted at appropriate rate depending upon the associated risk. Power of time (n) is assigned only to real risk-free rate of return and inflation premium to discount equity servicing and capital maintenance cash flows that are subject to exponential growth over time but not to the risk premium

    A novel Artificial Neural Network-based streamline tracing strategy applied to hypersonic waverider design

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    Streamline tracing in conical hypersonic flows is essential for designing high-performance waverider and intake. Conventionally, the streamline equations are solved after obtaining the velocity field from the solution of the axisymmetric conical flow field. The hypersonic waverider shape is generated from the base conical flow field by repeatedly applying the streamline tracing approach along several planes. When exploring the design space for optimization of the waverider, streamline tracing can be computationally expensive. We provide a novel strategy where first the Taylor-Maccoll equations for the inviscid axisymmetric conical flowfield and the streamlines from the shock are solved for a wide range of cone angle and Mach number conditions resulting in an extensive database. The streamlines are parametrized by a third-order polynomial, and an Artificial Neural Network (ANN) is trained to predict the coefficients of the polynomial for arbitrary inputs of Mach number, cone angle, and streamline originating location on the shock . We apply this strategy to design a cone derived waverider and compare the geometry obtained with the standard conical waverider design method and the simplified waverider design method. The ANN technique is highly accurate, with a difference of 0.68% with the standard in the coordinates of the waverider. RANS computations show that the ANN derived waverider does not indicate severe flow spillage at the leading edge, which is observed in the waverider generated from the simplified method. The new ANN-based approach is 20 times faster than the conventional method

    Effect of Diluents on the Extraction of Mercury(II) by n-Butyl Acetate

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    179-18

    Optimization and Development of Swellable Controlled Porosity Osmotic Pump Tablet for Theophylline

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    Purpose: To develop swellable controlled porosity osmotic pump tablet of theophylline and to define the formulation and process variables responsible for drug release by applying statistical optimizationtechnique.Methods: Formulations were prepared based on Taguchi Orthogonal Array design and Fraction Factorial design for core and coating, respectively. The tablets were prepared by direct compression and wet granulation methods; spray coated with ethyl cellulose solution containing varying amounts ofPEG 400 and plasdone. Drug release from the osmotic drug delivery system was studied using USP Type I paddle type apparatus. The membrane morphology of the delivery system was determined byscanning electron microscopy (SEM).Results: Optimization results indicated that the release rate of theophylline from the swellable controlled porosity osmotic pump tablet is directly proportional to the levels of osmotic agent, solubilizing agent andpore former in the tablet core and the membrane, respectively. SEM showed the formation of pores in the membrane through which drug release occurred. The best formulation showed 98.2 % drug releaseand complied with USP requirements.Conclusion: The results confirmed that the factors responsible for drug release were osmotic agents (core) and pore former (membrane). Also, the preparation of swellable controlled porosity osmotic pumptablet was facilitated by coating the core tablet with pore forming agent, thus eliminating the need for the more expensive laser drilling

    Managing the natural disasters from space technology inputs

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    Natural disasters, whether of meteorological origin such as Cyclones, Floods, Tornadoes and Droughts or of having geological nature such as earthquakes and volcanoes, are well known for their devastating impacts on human life, economy and environment. With tropical climate and unstable land forms, coupled with high population density, poverty, illiteracy and lack of infrastructure development, developing countries are more vulnerable to suffer from the damaging potential of such disasters. Though it is almost impossible to completely neutralise the damage due to these disasters, it is, however possible to (i) minimise the potential risks by developing disaster early warning strategies (ii) prepare developmental plans to provide resilience to such disasters, (iii) mobilize resources including communication and telemedicinal services and (iv) to help in rehabilitation and post-disaster reconstruction. Space borne platforms have demonstrated their capability in efficient disaster management. While communication satellites help in disaster warning, relief mobilisation and telemedicinal support, Earth observation satellites provide the basic support in pre-disaster preparedness programmes, in-disaster response and monitoring activities, and post-disaster reconstruction. The paper examines the information requirements for disaster risk management, assess developing country capabilities for building the necessary decision support systems, and evaluate the role of satellite remote sensing. It describes several examples of initiatives from developing countries in their attempt to evolve a suitable strategy for disaster preparedness and operational framework for the disaster management Using remote sensing data in conjunction with other collateral information. It concludes with suggestions and recommendations to establish a worldwide network of necessary space and ground segments towards strengthening the technological capabilities for disaster management and mitigation

    Resource-driven Substructural Defeasible Logic

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    Linear Logic and Defeasible Logic have been adopted to formalise different features relevant to agents: consumption of resources, and reasoning with exceptions. We propose a framework to combine sub-structural features, corresponding to the consumption of resources, with defeasibility aspects, and we discuss the design choices for the framework

    Cosmic ray tables - Asymptotic directions, variational coefficients and cut-off rigidities IQSY instruction manual no. 10

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    Cosmic ray deflections in geomagnetic field, variational coefficients, and diurnal intensity variations - table

    An evaluation of risk factors for major adverse cardiovascular events during tocilizumab therapy

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    Objective: To evaluate associations between lipid levels, inflammation, and rheumatoid arthritis (RA) disease activity, at baseline and during treatment, with the risk of major adverse cardiovascular events (MACE) in tocilizumab‐treated patients with RA. Methods: In retrospective post hoc analyses, data were pooled for 3,986 adult patients with moderate to severe RA who received ≥1 dose of tocilizumab (4 mg/kg or 8 mg/kg) intravenously every 4 weeks in randomized controlled trials and extension studies. Cox proportional hazards modeling was used to evaluate associations between baseline characteristics and posttreatment changes in laboratory and disease characteristics (week 24) and change in disease activity and laboratory values from baseline to week 24 with the risk of future MACE during extended followup. Results: We identified 50 independently adjudicated cases of MACE during 14,683 patient‐years of followup (0.34 MACE cases/100 patient‐years). At baseline, age, a history of cardiac disorders, the Disease Activity Score in 28 joints (DAS28), and the total cholesterol:high‐density lipoprotein cholesterol ratio were independently associated with MACE in multivariable models (P < 0.05 for all). During treatment, a higher DAS28 and higher swollen and tender joint counts at week 24 were associated with future MACE. In separate models, greater reductions in the DAS28 and joint counts from baseline to week 24 were inversely associated with future MACE; changes in lipid parameters were not statistically significantly associated with the risk of MACE. Conclusion: In this population of patients treated with tocilizumab, an association was observed between the baseline total cholesterol:high‐density lipoprotein cholesterol ratio and an increased risk of MACE. The risk of MACE while receiving treatment, however, was associated with control of disease activity but not lipid changes. Larger studies are needed to confirm these findings
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