A novel principle of a rotary piston valve and a high-frequency cylinder for a hydraulic actuation system are presented. This system will be utilized in metal-forming presses to superimpose a high-frequency oscillation on the movement of the ram. This technique was proven to enhance the forming parts quality, to extend the process limits and to reduce the forming force significantly. The key components of the valve are a stator and a rotary piston with radial drilled holes that is designed to provide a pulsating pressure and mass flow rate at a high frequency. A hydraulic cylinder is connected to the valve and converts the pulsating flow into a dynamic process force. The valve and the cylinder will be mounted on the bolster plate of a metal-forming press. In order to superimpose oscillation in the main forming direction, the cylinder is centered under the punch of the metal-forming tool. Three-dimensional computational fluid dynamics (CFD) simulations have been conducted to evaluate and to optimize the designs of the main components of the system. Hereby the commercial simulation code of ANSYS CFX was employed to determine the properties of the cylinder and the valve. Through its mesh motion technique, this simulation code allows the flow analysis between the rotary and the stationary part of the valve. Furthermore the dynamic characteristics of the system have been investigated under the influence of inertia and the compressibility of oil.

Natural gas is used as fuel in industries, power plants, commercial installations, and households. In its application, natural gas leaks can be considered as a major hazard because of its flammable and explosive nature. In addition to fuel, heat and oxygen sources, fires and explosions can occur if the concentration of natural gas in the air is between Low Flammable Limit (LFL) and Upper Flammable Limit (UFL). If the release of natural gas is not ignited, it will immediately form a Vapor Cloud Explosion (VCE) that can cause an explosion if it meets ignition point. Therefore, a research on dispersion patterns in a particular area or space is needed to minimize hazards and to develop safety procedures and regulations. This research aims to determine the external parameters that affect the dispersion and explosion caused by natural gas by using FLACS software from PT. Gexcon Indonesia. This software can display overpressure graphs of time and 3D visuals of simulations. The external parameters consist of vent size (5.4 m2 and 2.7 m2), wind direction, lighter position (center and back), day and night condition, and the presence of a obstacle (with and without obstacle). From the research results by the simulations, it is obtained that the highest overpressure value when there is an obstacle with a vent size of 2.7 m2; wind direction from the north; night condition, and back ignition point is 0.503 bars at 40, 835 s which can cause most buildings to collapse and the death rate to increase.

Consequences of an incident resulted from the release of hazards shall be mitigated to limit the undesirable effects. Emergency preparedness and response should address the duration and severity of the events and also prevent escalation. Therefore, emergency response plans are prepared, along with other related procedures, which are commonly called as preemergency responses. These plans or procedures are quick guidance used by the response team to handle emergency cases especially when it deals with critical equipment or condition. Each plan or case must involve related protection equipment available on site along with sequence for emergency command and hazard analysis.Common analysis provides only the highest magnitude of case or event (worst case scenario), therefore,this information could drive sequential preventive/mitigative actions which require significantly huge company resources to be deployed. To improve efficiency and effectiveness of this strategy, a review of consequence analysis using computational fluid dynamics approach is proposed. Several advantages of using this method are high quality presentation and visualization of phenomenon, ability to provide result monitoring over the period of time, and capacity to use several parameters on the analysis which were not available using the standard approach. Furthermore, this approach can enrich the information contained on the plans/procedures and enhance the quality of the plan representation to match with the actual scenarios. Hence by upgrading this pre-emergency response plans and procedures, it is expected that the emergency preparedness measures will be more comprehensively assessed and ready to provide best and optimum responses in emergencies.