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Full-Text Articles in Physical Sciences and Mathematics

An Experimental Investigation Of The Finite Time Efficiency Of A Peltier Refrigeration Device, Thomas Schneider Aug 1991

An Experimental Investigation Of The Finite Time Efficiency Of A Peltier Refrigeration Device, Thomas Schneider

Dissertations and Theses

Since the need of energy conservation has become more and more urgent in the past decades, there has been an increased interest in the study and development of more efficient energy conversion systems. One of the fields that have arisen from that endeavor is a branch of physics called Finite Time Thermodynamics (FIT). It may be said that FIT was initiated through the famous paper by Curzon and Ahlborn (1975) that established new bounds on the efficiency of a finite time Carnot heat engine. Before, the traditional treatments gave a fundamental upper limit on the efficiency of any heat engine. …


Behavior Of An Ion In A Bubble In The Ground State, Joung Hoon Oh May 1991

Behavior Of An Ion In A Bubble In The Ground State, Joung Hoon Oh

Dissertations and Theses

Deuterons might be trapped in a bubble embryo which occur s due to statistical fluctuation in heavy water. The size of the bubble embryo is expected to be an order of a small molecule. The ground state energy level which the deuteron may occupy in the bubble is calculated by solving the Schroedinger equation, and by considering the interaction between the trapped deuteron by a spherical bubble and the surrounding polarized liquid medium (heavy water). From the dependence of the energy eigenvalue of the ground state on the bubble radius, the pressure exerted on the bubble wall is obtained. It …


The Dimension Of A Chaotic Attractor, Roslyn Gay Lindquist May 1991

The Dimension Of A Chaotic Attractor, Roslyn Gay Lindquist

Dissertations and Theses

Tools to explore chaos are as far away as a personal computer or a pocket calculator. A few lines of simple equations in BASIC produce fantastic graphic displays. In the following computer experiment, the dimension of a strange attractor is found by three algorithms; Shaw's, Grassberger-Procaccia's and Guckenheimer's. The programs were tested on the Henon attractor which has a known fractal dimension. Shaw's and Guckenheimer's algorithms were tested with 1000 data points, and Grassberger's with 100 points, a data set easily handled by a PC in one hour or less using BASIC or any other language restricted to 640K RAM. …


Transient Heat Transfer, Eric Roth Jan 1991

Transient Heat Transfer, Eric Roth

Dissertations and Theses

With the advent of the new high Tc superconductors, liquid nitrogen will be one of the preferred cryogens used to cool these materials. Consequently, a more thorough understanding of the heat transfer characteristics of liquid nitrogen is required. In our investigations we examine the transient heating characteristics of liquid nitrogen to states of nucleate and film boiling under different liquid flow conditions. Using a platinum hot wire technique, it is verified that there is a premature transition to film boiling in the transient case at power levels significantly lower than under steady state nucleate boiling conditions. It is also shown …