3,778 research outputs found

    Superposition method for analysis of free-edge stresses

    Get PDF
    Superposition techniques were used to transform the edge stress problem for composite laminates into a more lucid form. By eliminating loads and stresses not contributing to interlaminar stresses, the essential aspects of the edge stress problem are easily recognized. Transformed problem statements were developed for both mechanical and thermal loads. Also, a technique for approximate analysis using a two dimensional plane strain analysis was developed. Conventional quasi-three dimensional analysis was used to evaluate the accuracy of the transformed problems and the approximate two dimensional analysis. The transformed problems were shown to be exactly equivalent to the original problems. The approximate two dimensional analysis was found to predict the interlaminar normal and shear stresses reasonably well

    Effectiveness of lending for vocational education and training: lessons from World Bank experience

    Get PDF
    This paper reviews the Bank involvement in the vocational education and training (VET) sub-sector in the 1990s. The paper aims to do just that, by mainly seeking answers to the following questions: 1) How has the Bank performed in its lending services to its clients in VET? 2) How have VET projects performed in terms of meeting stated objectives? 3) What factors led to the success, or failure of Bank operations? Based on what has been learned, the paper provides suggestions about how the performance of future VET interventions can be improved. This review concerns itself primarily with implementation performance, and proposes measures to improve project outcomes.ICT Policy and Strategies,Health Economics&Finance,Health Monitoring&Evaluation,Teaching and Learning,Banks&Banking Reform

    Residual thermal and moisture influences on the strain energy release rate analysis of edge delamination

    Get PDF
    A laminated plate theory analysis is developed to calculate the strain energy release rate associated with edge delamination growth in a composite laminate. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. The strain energy release rate, G, increased when residual thermal effects were combined with applied mechanical strains, but then decreased when increasing moisture content was included. A quasi-three-dimensional finite element analysis indicated identical trends and demonstrated these same trends for the individual strain energy release rate components, G sub I and G sub II, associated with interlaminar tension and shear. An experimental study indicated that for T300/5208 graphite-epoxy composites, the inclusion of residual thermal and moisture stresses did not significantly alter the calculation of interlaminar fracture toughness from strain energy release rate analysis of edge delamination data taken at room temperature, ambient conditions

    A new look at numerical analyses of free-edge stresses in composite laminates

    Get PDF
    The edge stress problem for a + or - 45 deg graphite/epoxy laminate was examined. The reliability of the displacement formulated finite element method in analyzing the edge stress problem was investigated. Analyses of two well known elasticity problems, one involving a stress discontinuity and one a singularity, showed that the finite element analysis yields accurate stress distributions everywhere except in two elements closest to the stress discontinuity of singularity. Stress distributions for a + or - 45 deg laminate showed the same behavior near the singularity found in the well known problems with exact solutions. The displacement formulated finite element method appears to be a highly accurate technique for calculating interlaminar stress in composite laminates. The disagreement among the numerical methods was attributed to the unsymmetric stress tensor at the singularity

    Experiencing space–time: the stretched lifeworlds of migrant workers in India

    Get PDF
    In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining

    Estimation of serum glutamic oxaloacetic transaminase, serum glutamic-pyruvic transaminase, gamma-glutamyl transferase and cholesterol levels in prolonged (30 years) daily consumption coffee in people

    Get PDF
    Background: Although prolonged (30years) coffee consumption has been associated with reduced or increased frequency of liver (SGOT, SGPT, GGT) enzymes and cholesterol levels, it is unclear whether the effect is from coffee or caffeine.Methods: A self-administered questionnaire ascertained lifestyle characteristics, including alcohol consumption, cigarette smoking, Diabetes mellitus and Dietary habits. As for drinking habit, examinees were first asked about their current drinking frequency (none, 1-2 times/ week, or almost daily) past or current smokers about the number of cigarettes smoked per day and the duration of smoking in years. As regards coffee, examinees were asked their usual daily intake in cups.Results: A total No of 200 cases were studied by dividing them into two group’s controls and cases. The results so obtain were compared with 50 healthy controls (not to consumed caffeine contained things that include nor coffee, tea, any type of cola’s). Statistical evaluation was carried out to confirm any deviation from the normal values. In men the mean serum SGOT, SGPT, GGT and cholesterol of cases is having higher level as compared to the mean value of controls. This increase is statistically highly significant (SGOT<0.0001, SGPT=0.045, GGT=0.0043, cholesterol<0.0001). In women’s the mean serum SGOT, SGPT, GGT and cholesterol of Cases is having higher level as compared to the mean value of Controls. This increase is statistically significant (SGOT< 0.05, SGPT=0.0319, GGT <0.0001, cholesterol: <0.0001).Conclusion: It has been shown from this study that prolonged daily consumption of coffee in many people it results increasing of levels of serum concentrations of the SGOT, SGPT, GGT and Cholesterol. It is observed that liver enzymes and cholesterol could be a target for caffeine or other components of coffee.

    Influence of light on serum cholesterol levels in complete (by birth) blind people

    Get PDF
    Background: With blindness normal stimulation of the hypothalamic pituitary axis is reduced. The serum cholesterol is frequently increased the upper limit of normal it is unclear whether the effect is due to complete absence of light, HPA axis function reduction or diurnal variation of melatonin levels.Methods: A self-administered questionnaire ascertained lifestyle characteristics, including alcohol consumption, cigarette smoking, diabetes mellitus and dietary habits. Inclusion criteria: 50 complete blindness persons (by birth), healthy adults, Age group between 30-50 years. Exclusion area: age 50, alcoholic, liver diseases, kidney diseases, diabetes mellitus, thyroid diseases.Results: A total No of 100 cases were studied by dividing them into two groups controls 50 and cases 50. The results so obtain were compared with 50 healthy controls (excluded consumed alcoholic, liver diseases, kidney diseases, diabetes mellitus, thyroid diseases.). Statistical evaluation was carried out to confirm any deviation from the normal values. The mean serum cholesterol of Cases (298.28±26.82) is having higher level as compared to the mean value of controls (153.38±11.79). This increase is statistically highly significant (<0.0001).Conclusions: It has been shown from this study with blindness normal stimulation of the HPA is reduced consequently the serum cholesterol is frequently increased the concentration may exceed the upper limit of normal. On this basis we observed increases the upper limit of the cholesterol levels in blind healthy people than subjects with normal healthy light perception

    The Eastwood-Singer gauge in Einstein spaces

    Full text link
    Electrodynamics in curved spacetime can be studied in the Eastwood--Singer gauge, which has the advantage of respecting the invariance under conformal rescalings of the Maxwell equations. Such a construction is here studied in Einstein spaces, for which the Ricci tensor is proportional to the metric. The classical field equations for the potential are then equivalent to first solving a scalar wave equation with cosmological constant, and then solving a vector wave equation where the inhomogeneous term is obtained from the gradient of the solution of the scalar wave equation. The Eastwood--Singer condition leads to a field equation on the potential which is preserved under gauge transformations provided that the scalar function therein obeys a fourth-order equation where the highest-order term is the wave operator composed with itself. The second-order scalar equation is here solved in de Sitter spacetime, and also the fourth-order equation in a particular case, and these solutions are found to admit an exponential decay at large time provided that square-integrability for positive time is required. Last, the vector wave equation in the Eastwood-Singer gauge is solved explicitly when the potential is taken to depend only on the time variable.Comment: 13 pages. Section 6, with new original calculations, has been added, and the presentation has been improve
    • …
    corecore