No description available.

In this thesis we have used temperature and high pressure to investigate the loss mechanisms present in visible, near infrared and infrared strained and unstrained semiconductor lasers. We find that tensile strained lasers show pressure dependent loss mechanisms similar in magnitude to those of unstrained and compressively strained devices. We present for the first time measurements of the temperature sensitivity of long wavelength lasers as a function of high pressure. Unstrained lasers show a pressure dependent temperature sensitivity whilst tensile strained lasers do not, over the range 150K to 300K. This leads us to conclude that phonon assisted Auger may be more significant than band to band Auger in tensile strained devices. We also demonstrate a possible mechanism for the decrease of Auger for these quantum well structures by estimating the effect of pressure on the gain - carrier density relation. High pressure measurements on 800nm GaAs quantum well lasers with superlattice barriers show the effect of changing the relative positions of the superlattice barrier IF and X minima. We find that the threshold current increases rapidly when the barrier is made indirect and conclude that this effect is due to repopulation of the barrier X minima with electrons from the active quantum well. For visible lasers we find that above lOkbar the effect of pressure on the threshold current is an increase which is attributable to losses from the active region to the X minima in the barrier. For a Philips bulk visible laser the threshold current remains relatively constant with pressure below lOkbar, whereas a Philips compressively strained device shows a decrease in Iý of about 25% up to 6kbar, a behaviour never seen before in short wavelength lasers. For the Philips 1% compressively strained laser the increase in Ith above 6kbar is also attributed to losses to the X minima. Measurements of a 1% compressively strained IBM laser showed immediate increases of threshold current with pressure, which is again attributed to the X minima in the barriers.

No description available.

Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Kalmia Kniel, Dept. of Animal & Food Sciences. Includes bibliographical references.

Thesis (M.S.)--Ohio University, November, 1989. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1993. / Title from PDF t.p.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Ben R. Hodges. Vita. Includes bibliographical references.

The object of this master’s thesis is design of a suitable hydrostatic travel drive for harvester. The first part dedicates of constructions of harvesters and actual different conceptions of travel drive. Next, there are design of hydrostatic circuit, calculation of general hydraulic parameters and design of hydraulic components in the second part. The last part deals with issue of combustion engine and cooler.

No description available.

An alternative method to overcome the high cost and time required for the design, analysis, construction and operating of a conventional water control structure is an inflatable dam. The basic aim of this project is to study both theoretically and experimentally the behaviour and performance of inflatable dams under hydrostatic and hydrodynamic conditions and to develop a design method. A finite element approach is developed in order to analyse air, water and a combination of air and water inflated dams to determine the shape and tension of the membrane of the dam under hydrostatic and hydrodynamic conditions. A series of models of inflatable dams were constructed and tested under hydrostatic and hydrodynamic conditions. The shapes of these models were compared with the theoretical shapes obtained from the theoretical analysis. The comparison shows there was a good relationship between the experimental and theoretical shapes. A new formula was derived for calculating the rate of flow over the air, water and air/water inflated dams theoretically. This develops the potential for applying an inflatable dam as a device for measuring discharge. A design technique for a dam was developed to design air, water and air/water inflated dams under hydrostatic conditions. This,technique can be used for the design of dams with different geometry of base length. computer programs were written for the analysis and design of the dams based on the finite element approach and considerable efforts were undertaken to simplify the input data and the output results. A sub-program was developed to provide the results in graphic form if required.