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This paper investigates a kind of KNTU1 non-diaphragm shock tube equipped with an innovative design valve within a driven tube. The shock tube is capable of generating a flat shock wave in its driven tube with a length to diameter ratio of 41/6. The KNTU1 shock tube is diaphragm-type and some limitations of this kind of shock tube such as the lack of repeatability without disassembling, the inability to adjust pressure ratio at a specified interval, and the inability to automate the shock tube caused a development on an automated shock tube. In this study, an innovative mechanism to achieve high-speed opening valve with an opening time of 8ms and 10ms is proposed. The unique feature of this automatic valve, compared with existing valves, is its opening from the center to the sides, such as the camera aperture. This is the best way to open the valve and smooth the wave and compensates for a part of the opening time of the valve. Also, the alignment of the driver and the drain prevents disturbances caused by the redirection or rotation of the gas seen in most valves. These help optimize the shock tube. Another initiative in this paper is the design and construction of an optical system to measure the speed and the moment of shock wave arrival to check the shape surface of the shock wave. This system has the ability to move in driven. This paper has been compiled to compare theoretical and experimental data of shock wave. [ABSTRACT FROM AUTHOR]

In this paper a nonlinear controller is going to be designed for micro-beam's deflections under mechanical shock effects. The micro-beam is supposed to undergo mechanical shocks. Mechanical shocks are one of the failure sources and the controller is to considerably suppress shock's unfavorable effects. Half-Sine, rectangular and triangular pulses are chosen as reference shock signals to represent true complicated shock signals in nature which consist of different harmonics. Two layers of electrodes are placed in both sides of the micro-beam and they are used to actuate the micro-beam by different voltage levels. Upper layer is specifically meant for control purpose. Nonlinear equations governing micro-beam's deflection dynamics are derived, discretized by Galerkin method to a set of nonlinear duffing type ODE and used to investigate micro-beams response to each shock input signal. Controller design is based on a simple nonlinear model formed by micro-beam's first mode shape. Proper second order behavior is generated by feedback linearization method as controller logic. Finally controller performance and shock rejecting capability is evaluated by numerical simulations. Controller is shown to be very effective in diminishing shock unfavorable effects and postponing pull-in instability by numerical simulations. [ABSTRACT FROM AUTHOR]

This paper deals with the role of fast ignitor in fast-shock ignition (FSI) concept. The semi-analytical model indicates that the FSI target gain is a function of fast ignitor laser wavelength. If the energy of fast ignitor driver is ≈ Eifopt and the laser wavelength is less than 0.53 micron, then with a fuel mass about 2 mg the FSI has a considerable advantage over pure shock ignition and the figure of merit is better than 1.2. When the wavelength of fast ignitor becomes shorter, the Eif approaches Eifopt, and for wavelengths shorter than 0.25 micron no additional is advantage is obtained. [ABSTRACT FROM AUTHOR]