12,823 research outputs found
Automatic closed circuit television arc guidance control Patent
Automatic closed circuit television arc guidance control for welding joint
Comparison of finite-difference schemes for analysis of shells of revolution
Several finite difference schemes are applied to the stress and free vibration analysis of homogeneous isotropic and layered orthotropic shells of revolution. The study is based on a form of the Sanders-Budiansky first-approximation linear shell theory modified such that the effects of shear deformation and rotary inertia are included. A Fourier approach is used in which all the shell stress resultants and displacements are expanded in a Fourier series in the circumferential direction, and the governing equations reduce to ordinary differential equations in the meridional direction. While primary attention is given to finite difference schemes used in conjunction with first order differential equation formulation, comparison is made with finite difference schemes used with other formulations. These finite difference discretization models are compared with respect to simplicity of application, convergence characteristics, and computational efficiency. Numerical studies are presented for the effects of variations in shell geometry and lamination parameters on the accuracy and convergence of the solutions obtained by the different finite difference schemes. On the basis of the present study it is shown that the mixed finite difference scheme based on the first order differential equation formulation and two interlacing grids for the different fundamental unknowns combines a number of advantages over other finite difference schemes previously reported in the literature
Global estimates and projections of mortality by cause, 1970-2015
The authors report estimates and projections of deaths by cause for major world regions, based on data from country reports to the World Health Organization and regression models. They report mortality rates for seven major causes: infectious and parasitic diseases, neoplasms, circulatory system diseases, complications of pregnancy, certain perinatal conditions, injury and poisoning, and other causes. Some more specific causes are reported on. They give estimates for six age groups by sex for four years (1970, 1985, 2000, and 2015) and six country groups: industrial market economies, industrial nonmarket economies, Latin America and the Caribbean, sub-Saharan Africa, the Middle East and North Africa, and Asia and the Pacific. Among their findings: The population over 45 in developing countries is projected to more than double between 1985 and 2015, rising from 17 to 24 percent of the population. Causes of death, which are closely related to age at death, must change accordingly. Infant mortality in developing countries is projected to fall from 78 per thousand in 1985 to 43 per thousand in 2015 and life expectancy at birth in developing countries is projected to rise by five years. The leading causes of death for the world as a whole for both 1970 and 1985 were infectious and parasitic diseases and circulatory system diseases - with the first more important in developing countries, and the second more important in developed countries. Certain perinatal conditions were also more important for developing countries, but accounted for only a fourth or a fifth as many deaths in 1985. Neoplasms were more important in developed than in developing countries. Deaths from infectious diseases are expected to decline as a percentage of deaths; proportionate deaths from diseases of the circulatory system are expected to rise. The greatest number of deaths will continue to be in Asia, where almost half of all deaths in the world take place. This proportion is not projected to change. Better data on causes of death are essential. The World Health Organization is working with countries to strengthen their cause-of-death information systems as an essential support for health monitoring.Health Monitoring&Evaluation,Health Indicators,Early Child and Children's Health,Adolescent Health,Demographics
Results of a search for deuterium at 25-50 GC/c using a magnetic spectrometer
A method is presented for separately identifying isotopes using a Cerenkov detector and a magnet spectrometer. Simulations of the method are given for separating deuterium from protons. The simulations are compared with data gathered from the 1979 flight of the New Mexico State University balloonborne magnet spectrometer. The simulation and the data show the same general characteristics lending credence to the technique. The data show an apparent deuteron signal which is (11 + or - 3)% of the total sample in the rigidity region 38.5 to 50 GV/c. Until further background analysis and subtraction is performed this should be regarded as an upper limit to the deuteron/(deuteron+proton) ratio
Recurrence interval analysis of high-frequency financial returns and its application to risk estimation
We investigate the probability distributions of the recurrence intervals
between consecutive 1-min returns above a positive threshold or
below a negative threshold of two indices and 20 individual stocks in
China's stock market. The distributions of recurrence intervals for positive
and negative thresholds are symmetric, and display power-law tails tested by
three goodness-of-fit measures including the Kolmogorov-Smirnov (KS) statistic,
the weighted KS statistic and the Cram\'er-von Mises criterion. Both long-term
and shot-term memory effects are observed in the recurrence intervals for
positive and negative thresholds . We further apply the recurrence interval
analysis to the risk estimation for the Chinese stock markets based on the
probability , Value-at-Risk (VaR) analysis and VaR analysis
conditioned on preceding recurrence intervals.Comment: 17 pages, 10 figures, 1 tabl
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