Ashfaq Ahmad — новинки

The objective of this work is to compute the mechanical stresses within transformer resulting from the excessive short-circuit currents. The forces and stresses set up in transformer windings and their clamping structures, as the result of external or internal short-circuits or of switching operations, are considered in detail. Various arrangements of windings in large power transformers are described. Points at which particularly high mechanical stresses occur in concentric windings are discussed in detail. Analytical and FEM (Finite Element Method) calculation for both types of short circuit forces, axial and radial have been discussed. The result was then compared with actual measurements on a prototype 20MVA 132 /11.5KV power transformer. Various failure mechanisms due to these forces have been elucidated. Axial forces between the top and bottom halves of each winding or between different windings are responsible for bending stresses in turns near the ends or adjacent to gaps in the windings, for compressive stresses in the body of the winding, and for tensile and compressive stresses in the clamping gear. Radial forces produce tensile stresses in the outer and buckling stress

There is endless literature on job stress, but not a single book on the subject specifically written in the context of Pakistan. The book in hand is the first ever empirical study to discuss the global problem of job stress in relation to work environment in Pakistan. It empirically tests the significance of relationship between work environment and work stress in this South Asian country. The study contains voluminous literature review on stress, which will be extremely beneficial to researchers planning to undertake fresh research on the subject, particularly with reference to Pakistan. The main objective of the study is to see whether the employees in Pakistan also suffer from the global problem of work stress; if so, what causes stress in this part of the world and what is the extent and gravity of the problem. The study also covers the gender disparities in discussion of the chief factors as well as the outcomes of stress.

A field experiment was conducted at the agronomic research area, University of Agriculture, Faisalabad, in order to study the effect of different levels of nitrogen and magnesium on growth, yield and quality of hybrid maize (Cargil 707). The crop was sown in 70 cm spaced rows, while plant to plant distance was maintained at 15 cm with the help of the Dibbler. The experiment was laid out in randomized complete block design (RCBD) with three replication using a net plot size of 3.5 x 7.5 m. Experimental treatments comprised of (T0); 0-0, (T1); 100 kg N + 10 kg Mg, (T2); 100 kg N + 15 kg Mg, (T3); 150 kg N + 10 kg Mg, (T4); 150 kg N + 15 kg Mg, (T5); 200 kg N + 10 kg Mg, (T6); 200 kg N + 15 kg Mg per hectare. The source of N and Mg was urea and MgCl2 , respectively. Recommended doses of P2O5 and K2 O at the rate of 100 kg per hector of each in the form DAP and KCl, respectively were used as a basal dose. The crop was planted on autumn & harvested in the month of December and the data was recorded by using the standard procedures.