Thin-walled square columns are generally used as impact energy absorber in automotive structures due to their ease of fabrication and installation, high energy absorption capacity in terms of progressive plastic deformation and long stroke. However, the main drawback of standard square column is the high initial peak force. An external tapered plunger is proposed to overcome this shortcoming while at the same time, improving the impact performance. Static and dynamic axial crushing were performed by theoretical and finite element analysis to determine the initial peak force (IPF), crush force efficiency (CFE) and plastic specific energy absorption (SEA) of columns with external plunger of various taper angles. The simulations results were validated by experiments. It was found that the external plunger significantly enhanced the column impact performance and the deformation characteristics as well. Comparison with plain square column was carried out and it was found that the concentric plunger reduced the initial peak force and increased the crush force efficiency for both static and dynamic loading conditions.

In this research, slurry erosion-corrosion and slurry-erosion resistances of electroless Ni-P coatings have been investigated. These coatings were applied on AISI 5117 steel discs by electroless deposition process and then they were heat treated at 650 C for 1 h. Slurry erosion-corrosion and slurry-erosion resistances of deposits were measured by the whirling-arm tester. Also, microstructure of deposits before and after heat treatment was evaluated by X-ray diffraction (XRD) analysis. The results showed that the electroless Ni-P plating greatly increased the erosion and erosion-corrosion resistances for all impact angles. Moreover, the effectiveness of plating was the highest for an impact angle of 45o , where the erosion and erosion-corrosion resistances were increased by 60% and 70% respectively, compared with that of the substrate. The results showed also that the coated and blank specimens behaved as ductile materials under erosion and erosioncorrosion tests and the maximum weight loss occurred at an impact angle of 45o .

This paper proposes a robust H2 feedback controller design for damping power system oscillations over a wide range of operating conditions. Robust H2 control technique based power system controller is developed for both excitation system and speed governor control. The effectiveness of the proposed power system controller is validated by a simple power system composed of a synchronous generator connected to an infinite bus through a transmission line. A comparison between power system responses at variety of operating conditions using the proposed H2 controller and Linear Quadratic Regulator LQR control is obtained. The digital simulation results prove the powerful of the proposed power system controller based on H2theory in terms of fast power system mechanical oscillation damping over a wide range of operating conditions with system uncertainty and parameters change.

In this paper a system identification toolbox for MATLAB is introduced, including a user friendly graphical user interface. The toolbox is appropriate for the identification of systems in discrete-time linear parameter varying (LPV) form. Using LPVIOID1 it is possible to identify input-output models in open-loop and closed-loop settings based on experimental data. It comprises several recent LPV identification techniques. Furthermore, a novel method for identifying unstable plants in closed-loop is proposed. The toolbox is equipped with several tools for model validation. Examples for illustration are included.

In this paper a system identification toolbox for MATLAB is introduced, including a user friendly graphical user interface. The toolbox is appropriate for the identification of systems in discrete-time linear parameter varying (LPV) form. Using LPVIOID1 it is possible to identify input-output models in open-loop and closed-loop settings based on experimental data. It comprises several recent LPV identification techniques. Furthermore, a novel method for identifying unstable plants in closed-loop is proposed. The toolbox is equipped with several tools for model validation. Examples for illustration are included.

In this paper a system identification toolbox for MATLAB is introduced, including a user friendly graphical user interface. The toolbox is appropriate for the identification of systems in discrete-time linear parameter varying (LPV) form. Using LPVIOID1 it is possible to identify input-output models in open-loop and closed-loop settings based on experimental data. It comprises several recent LPV identification techniques. Furthermore, a novel method for identifying unstable plants in closed-loop is proposed. The toolbox is equipped with several tools for model validation. Examples for illustration are included.

Technology controls our life in almost all fields. Health services are one of these fields which are widely affected by the advances in spatial information technology. Spatial information technology includes Geographic Information Systems (GIS), Global Positioning Systems (GPS), remote sensing, and spatial data management. GIS helps planners in planning and monitoring health care facilities. This enables health authorities matching the facility supply with the relevant demand. Utilization of GIS spatial analysis also promotes the standards of health services. That is why health authorities give investment priority to improve health services employing GIS. Other Applications of GIS and GPS in emergency geographic information services and infection control are appeared. Using GIS in planning new health care facility opens multiple issues. These issues are the locality definition, spatial epidemiology, socio- economic status and health status taking into account age and sex variations in the area concerned. In this paper, the existing situation of public health care facilities in Assuit city, Egypt is assessed according to the guidelines of the Ministry of Health and Population in Egypt "MOHP".

Pillars are designed to ensure regional stability or local support in stopes and along drifts, or to yield under a measure of control. In all cases, the strength of the material and the variations in strength must be known both for the pillar and for the roof and floor. The stability in longwall faces depends mainly on the interaction between the roof strata, face support, roadway support and dimensions of pillars. The main aim of this paper is to apply rock mass classification systems to longwall pillar design at Abu-Tartur mining area. The pillar load is estimated taking into account the physical and mechanical properties of phosphate deposit and roof rock, panel width, mining height, depth below surface. Two methods from classification systems are used in calculation pillars stress and strength to pillars design namely Geological Strength Index (GSI) and Rock Mass Rating (RMR) systems. GSI values for immediate, main roof rocks and phosphate ores are determined from geological conditions, as lithology, structure of the interlocking of rock blocks and the conditions of the surfaces between these blocks. RMR value can be determined by correlation it with GSI system. The pillar widths calculated by applying rock mass classifications (GSI& RMR) are 49m and 64m at a factor of safety 2 and panel width 100m with extraction ratios of 70 and 64 % respectively. The data used in calculations are collected from geological reports of the company and from laboratory tests of phosphate ores and shale rocks in the roof.

Pillars are designed to ensure regional stability or local support in stopes and along drifts, or to yield under a measure of control. In all cases, the strength of the material and the variations in strength must be known both for the pillar and for the roof and floor. The stability in longwall faces depends mainly on the interaction between the roof strata, face support, roadway support and dimensions of pillars. The main aim of this paper is to apply rock mass classification systems to longwall pillar design at Abu-Tartur mining area. The pillar load is estimated taking into account the physical and mechanical properties of phosphate deposit and roof rock, panel width, mining height, depth below surface. Two methods from classification systems are used in calculation pillars stress and strength to pillars design namely Geological Strength Index (GSI) and Rock Mass Rating (RMR) systems. GSI values for immediate, main roof rocks and phosphate ores are determined from geological conditions, as lithology, structure of the interlocking of rock blocks and the conditions of the surfaces between these blocks. RMR value can be determined by correlation it with GSI system. The pillar widths calculated by applying rock mass classifications (GSI& RMR) are 49m and 64m at a factor of safety 2 and panel width 100m with extraction ratios of 70 and 64 % respectively. The data used in calculations are collected from geological reports of the company and from laboratory tests of phosphate ores and shale rocks in the roof.

Pillars are designed to ensure regional stability or local support in stopes and along drifts, or to yield under a measure of control. In all cases, the strength of the material and the variations in strength must be known both for the pillar and for the roof and floor. The stability in longwall faces depends mainly on the interaction between the roof strata, face support, roadway support and dimensions of pillars. The main aim of this paper is to apply rock mass classification systems to longwall pillar design at Abu-Tartur mining area. The pillar load is estimated taking into account the physical and mechanical properties of phosphate deposit and roof rock, panel width, mining height, depth below surface. Two methods from classification systems are used in calculation pillars stress and strength to pillars design namely Geological Strength Index (GSI) and Rock Mass Rating (RMR) systems. GSI values for immediate, main roof rocks and phosphate ores are determined from geological conditions, as lithology, structure of the interlocking of rock blocks and the conditions of the surfaces between these blocks. RMR value can be determined by correlation it with GSI system. The pillar widths calculated by applying rock mass classifications (GSI& RMR) are 49m and 64m at a factor of safety 2 and panel width 100m with extraction ratios of 70 and 64 % respectively. The data used in calculations are collected from geological reports of the company and from laboratory tests of phosphate ores and shale rocks in the roof.