International Journal of Engineering
Volume:12 Issue: 4, Nov 1999

Results of an experimental investigation of the seismic performance of prefabricated column-footing connections are presented. Tests were conducted on six 1/4-scale prefabricated column specimens inserted into prefabricated footings in two Groups. Group-1 consisted of four specimens, which were tested under constant axial load and cyclic inelastic lateral displacements. The remaining two specimens in group-2, were subjected to cyclic inelastic lateral displacements only for comparison. Test results showed that this type of connection exhibits relatively higher ultimate strength comparable to fixed end connections, and fairly acceptable ductile behavior. Also the test results indicate the strength reduction in post-elastic state and the connection behavior as a semi-rigid joint.

In order to obtain more accurate predicted dynamic steady-state performance with shorter computation time, an available mathematical model is modified and presented. Using this modified model, performance of a typical switched reluctance motor (SRM) under a wide range of variations of operating conditions is obtained and discussed. These include variations of speed, voltage, load and switching angle. The static test characteristics of the motor are carefully measured and the measured flux-linkage data are then used to predict the steady-state performance.

This paper present unequal-sized facilities layout solutions generated by a genetic search program named LADEGA (Layout Design using a Genetic Algorithm). The generalized quadratic assignment problem requiring pre-determined distance and material flow matrices as the input data and the continuous plane model employing a dynamic distance measure and a material flow matrix are discussed. Computational results on test problems are reported as compared with those of layout solutions generated by the branch and bound algorithm, a hybrid method merging simulated annealing and local search techniques and an optimization process of an enveloped block.

In the present work, the solidification process was simulated in both macroscopic and microscopic scales. Two-dimensional heat transfer equation for conduction was applied for macroscopic modeling using enthalpy formulation and finite element method. In order to decrease execution time and/or memory capacity in finite analysis, skyline mathematical technique was adapted. The microenthalpy method using kinetic equations for microstructure formation was used for microscopic modeling. This macro-micrimodelling is able to represent transient thermal field of the system, the enthalpy and solid fraction distributions, and different aspects of microstructure: grain density, size, eutectic interlamellar and dendrite arm spacings. A good agreement was found between our numerical data with some experimental results from several research sources.

Combined radiation and natural convection within the annular region of two infinitely long horizontal concentric cylinders are investigated numerically in this research. Radial and tangential radiation effects ate considered using Milne-Eddington approximation for a two-dimensional radiative transfer. The basic conservation equations are discretized with the finite volume method and SIMPLER algorithm. The result are presented through velocity vector field, streamline and isothermal plots. It is observed that radiation has significant effect on flow and temperature fields. Results of local Nusselt number prediction along the surface of the inner cylinder show that radiation suppresses the angular dependence of Nusselt number.

Abstract This investigation deals with M/M/R/N machine repair problem with R non-reliable service stations which are subjected to unpredictable breakdown. 1here is provision of an additional server to reduce backlog in the case of heavy load of failed machines. 1he permanent service stations repair the failed machines at an identical rate m and switch to faster repair rate when all service stations are busy. By using matrix geometric theory, the formulae for obtaining the optimal number of service stations is derived.