Experimental Study of Pulse Tube Refrigerators

The working fluid for the pulse tube refrigerator is Helium, which is non-toxic to humans and harmless to the environment. The Pulse Tube Refrigeration unit offers a viable alternative to units that currently require CFC and HCFC working fluids. Pulse Tube Refrigerators can be operated over wide range of temperatures. These units can be used in numerous space and commercial applications, including food freezers freeze dryers. It can also be used to cool detectors and electronic devices. The design of Pulse Tube Refrigeration Unit was based on Orifice Pulse Tube Concept. First the gas is compressed in a compressor. Next it floes through the compressor after cooler, where heat is rejected to the water cooled loop. Then the gas enters the regenerator and cold end heat exchanger where heat is added to the gas from surroundings. The gas finally enters the Pulse Tube, orifice and reservoir. These three components produce the phase shift of mass flow and pressure, which is necessary for cooling. The gas shuttles forth between hot and cold ends. Heat is lifted against the temperature gradient and rejected at hot end heat exchanger, which is water cooled

On Synthesis of (k,K) Circuits.

circuit is one which can be decomposed into nonintersecting blocks of gates where each block has no more than K external inputs, such that the graph formed by letting each block be a node and inserting edges between blocks if they share a signal line, is a partial k-tree. (k;K) circuits are special in that they have been shown to be testable in time polynomial in the number of gates in the circuit, and are useful if the constants k and K are small. We demonstrate a procedure to synthesise (k;K) circuits from a special class of Boolean expressions

Detecting embedded horn structure in propositional logic

We show that the problem of finding a maximum renamable Horn problem within a propositional satisfiability problem is NP-hard but can be formulated as a set packing and therefore a maximum clique problem, for which numerous algorithms and heuristics have been developed

Partial instantiation methods for inference in first-order logic

Satisfiability algorithms for propositional logic have improved enormously in recently years. This improvement increases the attractiveness of satisfiability methods for first-order logic that reduce the problem to a series of ground-level satisfiability problems. R. Jeroslow introduced a partial instantiation method of this kind that differs radically from the standard resolution-based methods. This paper lays the theoretical groundwork for an extension of his method that is general enough and efficient enough for general logic programming with indefinite clauses. In particular we improve Jeroslow's approach by (1) extending it to logic with functions, (2) accelerating it through the use of satisfiers, as introduced by Gallo and Rago, and (3) simplifying it to obtain further speedup. We provide a similar development for a dual partial instantiation approach defined by Hooker and suggest a primal-dual strategy. We prove correctness of the primal and dual algorithms for full first-order logic with functions, as well as termination on unsatisfiable formulas. We also report some preliminary computational results

Volume modelling for emerging manufacturing technologies

The next generation manufacturing technologies will draw on new developments in geometric modelling. Based on a comprehensive analysis of the desiderata of next generation geometric modellers, we present a critical review of the major modelling paradigms, namely, CSG, B-Rep, non-manifold, and voxel models. We present arguments to support the view that voxel-based modellers have attributes that make it the representation scheme of choice in meeting the emerging requirements of geometric modelling

Design and Manufacturing of Smart Braking System

Now a days, vehicles have been developed a lot and reach its new margin; but yet accidents are mostly occurred by retard of the driver to stomp the brake or by the sloppiness of the driver or over speed or due to unpleasant weather. So our project points to emerge a system which can actuate the braking system automatically with the aid of high profile sensors with relay circuit and some more changes in conventional braking system which can actuate the brake automatically in emergency state. The brain of this entire set-up is Arduino microcontroller. The ultrasonic sensors are the vision of this system and stepper motor utilised for actuation. This system has been composed to depict the technological improvement in further. In future the actual model may be evolved based on its viability