Advanced Materials Research Vol. 1016

Abstract: Asymmetric meshing is a perturbation introduced in the numerical model without changing geometry, loading or boundary conditions. Asymmetric meshing is employed in the form of a band along axial direction of the shell model, the elements size in the axial band is reduced as compared with the rest of shell to produce asymmetry in the meshing and four amplitudes of asymmetry are used in a particular band. Asymmetric meshing affects predicted buckling load, buckling mode shape and post-buckling behaviour. The reduction in the buckling load using asymmetric meshing was observed to be about 18%, which depends mainly on area of asymmetric meshing and less on different magnitudes of asymmetry in the same area. The load-displacement curve behaviourusing asymmetric meshing technique is quite similar to the curve obtained by introducing geometric imperfection in the shell model.

Abstract: This paper exploits the guidance algorithms to assembly multiple vehicle in close proximity. The objective is to move each vehicle in the assembly to its final location. The guidance laws are determined such that, each vehicle should attract to the others on long distances and avoid collision with them in short distances. These laws are based on Lyapunov’s second method that utilize the potential function theory to insure the stability of the assembly process. Numerical investigations were performed for different configurations of the assembly. The proposed algorithms may prove useful for future mission applications such as satellite formation flying, structures assembly in space and mobile robots control.

Abstract: In recent decades, philosophy behind maintenance has varied consistently due to the changes in complexity of designs, advances in automation and mechanization, adaptation to the fast growing market demand, commercial computation in the sectors, and environmental issues. In mid-forties, simplicity of designs, limited maintenance opportunities, and immaturity of trade culture made enough to perform only fix it when it broke approach, i.e. corrective maintenance, after failures. Last quarter of the 21^th century made essential to constitute more conservative and preventive maintenance policies in order to ensure safety, reliability, and availability of systems with longer lifetime and cost effectiveness. Preventive maintenance can provide an economic saving more than 18% of operating cost of systems. In this basis, various stochastic models were proposed as a tool to constitute a maintenance policy to measure system availability and to obtain optimal maintenance periods. This paper presents a general perspective on common stochastic models in maintenance planning such as Homogenous Poisson Process, Non-Homogenous Poisson Process, and Imperfect Maintenance. The paper also introduces two common maintenance policies, block and age replacement policy, using these stochastic models.

Abstract: During the previous recent years, non-invasive schemes of facial image studies have been confirmed to be outstanding and dependable instrument to analyze the pain condition. This paper proposes a new feature vector based principal Component Analysis (PCA) for the pain detection. Different Eigen vector are proposed to evaluate the performance of the proposed features. In this work, Infant COPE database is used with illumination added. Homomorphic Filter (HOMO) is applied to remove the shadow. K-NN classifier is employed for testing the proposed features. The experimental outcomes uncover that the suggested features provide very promising results which is higher than 90% for Infant COPE database.

Abstract: The tube is a significant machine part in a car.It provides the important contact and fixed functions during the steering of a car. An inaccurate tube size cannot provide steering stability. For example, if the difference in diameter between the front and back of a tube is very large, the car moving at high speeds will be to swing, although steering would still be possible. A car can be made safer at high speeds by controlling the difference between the front and back diameters of the tube. High temperature welding of various parts to the tube, heats the tube almost 2,000°C, so the consequent deformation of the tube must be controlled.

Abstract: Water mist technology has been developed and regarded as a promising substitute fire-extinguishing agent in spacecraft. In this paper, a numerical simulation method is introduced to investigate the effect of water mist size, velocity and flow rateon the fire suppressionefficiencyin microgravity. The fire extinguishing efficiency is better for the finer water mist in microgravity due to better heat transfer and more rapid vaporization. The evaporation cooling is the dominant mechanism of fire suppression in microgravity.As for the water mist velocity, the performance of fire suppression is affected slightly in microgravity. The results on the effect of water flow rate show that the flow rate should be higher than a critical value to suppress the fire effectively.

Abstract: In this research, a bi-criteria heuristic is proposed to find non-dominated solutions for scheduling unrelated parallel machines with release dates that minimizes makespan andtotal weighted tardiness.