The role of high infrared (IR) reflectance in the temperature regulation of a single species of cactus, Cereus giganteus (saguaro cactus), was investigated. Two independent methods were used to determine the effect of high near-IR reflectance on C. giganteus stem temperatures. The first method was to measure the surface temperature of two individual plants of comparable size and health, one of which was partially shaded by a canopy of loose sun-screening material. The second method involved the numerical solution on a computer of the energy balance, or heat transfer, equation for C. giganteus. High reflectance at near-IR wavelengths was found to decrease the peak surface temperature reached by C. giganteus by 3.2 to 3.3°C. This figure is valid for the fairly mild environmental conditions encountered in the Sonoran Desert at an altitude of 940 m during late September and early October.

Approved for public release; distribution is unlimited / Exploring semiconductor lifetime, reliability and performance is a never-ending science for today's modern electronics. One significant problem that affects all of these areas is radiation-induced damage. Making calculations to determine how semiconductor devices will hold up in radiation-harsh environments has to be achieved in order to determine system lifetime once placed in their operational capacity. Today's high-technology investments in such areas as satellite design, medical advances, military and commercial hardware, demand thorough understanding in radiation damage. Modeling semiconductor devices with computer-based simulation will provide a cost and time savings over a repetitive design and testing sequence. This thesis models and simulates an industry standard solar cell and a light emitting diode (LED), using the SILVACO ATLASTM computer-based program. Using this software, these simulations are generated based on known radiation-induced defects on gallium arsenide (GaAs) semiconductive devices derived from Deep Level Transient Spectroscopy (DLTS) studies. A comparison is then made with another radiation-induced damage prediction method, known as Non-Ionizing Energy Loss (NIEL), to see if the SILVACO ATLASTM models can be used as an alternative. / Lieutenant, United States Navy

Approved for public release; distribution is unlimited / The effects of radiation in GaAs solar cells has been extensively researched and the results of numerous investigation have yielded a considerable amount of information about the degradation in irradiated solar cells. This thesis establishes a novel method in which to use Silvaco's physically-based device simulator, ATLAS, to model the effects of radiation on solar cell output characteristics. A virtual model representing a single junction GaAs solar cell was created in ATLAS. The effects of radiation were modeled using carrier trapping statements representing the defects associated with various fluence levels of 1 MeV electron radiation which were characterized with Deep Level Transient Spectroscopy techniques. The resulting output characteristics of the virtual solar cell, illuminated with a simulated AM0 spectrum, were compared to published experimental measurements for GaAs solar cells of the same dimensions. The virtual solar cell demonstrated a good correlation between the measured and virtual solar cell output characteristics and accurate representation of the spectral response. Complete ATLAS and MATLAB codes are included in appendices. / Major, United States Marine Corps

No description available.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, June, 2013 / Diamond with its outstanding and unique physical properties offers the opportunity to be used as semiconductor material in future device technologies. Promising ap- plications are, among others, high speed and high-power electronic devices working under extreme conditions, such as high temperature and harsh chemical environments. With respect to electronic applications, a controlled doping of the material is neces- sary which is preferably done by ion implantation. The ion implantation technique allows incorporation of foreign atoms at de¯ned depths and with controlled spatial distribution which is not achievable with other methods. However, the ion implanta- tion process is always connected with the formation of defects which compensate and trap charge carriers thus degrading the electrical behaviour. It is therefore essential to understand the nature of defects produced under various implantation conditions. In this respect, this study involves the investigation of the nature of the radiation damage produced during the multi-implantation of carbon ions in synthetic high- pressure, high-temperature (HPHT) type Ib diamond spread over a range of energies from 50 to 150 keV and °uences, using the cold-implantation-rapid-annealing (CIRA) routine. Single energy implantation of carbon ions in synthetic HPHT (type Ib), at room temperature, was also performed. Both ion milling and FIB (Focused Ion Beam) milling were used to prepare thin specimen for transmission electron micro- scope (TEM) analysis. The unimplanted, implanted and annealed samples were characterized using trans- mission electron microscopy based techniques and Raman spectroscopy. ii iii In unimplanted type Ia natural diamond, a high density of platelets, exhibiting the typical contrast of both edge-on and inclined platelets on f100g planes was found. As-implanted HPHT type Ib diamond, implanted with single energy of 150 keV car- bon ions and °uence of 7£1015 ions cm¡2 revealed an amorphous diamond layer of about 80 nm in thickness while, for low °uence implantations, the damaged diamond retained its crystallinity after annealing at 1600 K. In addition, damaged diamond transformed into disordered carbon comprising regions with bent (002) graphitic fringes and regions of amorphous carbon when high °uence, i.e., one above the amor- phization/graphitisation threshold were used followed by rapid thermal annealing at 1600 K. Furthermore, the interface between the implanted and annealed layer and the diamond substrate at the end of the range, showed diamond crystallites, inter- spersed between regions of amorphous carbon and partially graphitized carbon. This indicates that solid phase epitaxial recrystallization regrowth in diamond does not occur.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

Bibliography: leaves 216-250. / xii, 250 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / To determine the acute and subacute effects of therapeutic irradiation on oescophageal, gastric and intestinal function; the chronic effects of irradiation on gastric, intestinal and anorectal function, and, the effects of loperamide-N-oxide in patients with diarrhoea due to chronic radiation enteritis. / Thesis (M.D.)--University of Adelaide, Dept. of Medicine, 1996?

No description available.

Radiation causes performance degradation in electronics by inducing atomic displacements and ionizations. While radiation hardened components are available, non-radiation hardened electronics can be preferable because they are generally more compact, require less power, and less expensive than radiation tolerant equivalents. It is therefore important to characterize the performance of electronics, both hardened and non-hardened, to prevent costly system or mission failures. Radiation effects tests for electronics generally involve a handful of step irradiations, leading to poorly-resolved data. Step irradiations also introduce uncertainties in electrical measurements due to temperature annealing effects. This effect may be intensified if the time between exposure and measurement is significant. Induced activity in test samples also complicates data collection of step irradiated test samples. The University of Texas at Austin operates a 1.1 MW Mark II TRIGA research reactor. An in-core irradiation facility for radiation effects testing with a real-time monitoring capability has been designed for the UT TRIGA reactor. The facility is larger than any currently available non-central location in a TRIGA, supporting testing of larger electronic components as well as other in-core irradiation applications requiring significant volume such as isotope production or neutron transmutation doping of silicon. This dissertation describes the design and testing of the large in-core irradiation facility and the experimental campaign developed to test the real-time monitoring capability. This irradiation campaign was performed to test the real-time monitoring capability at various reactor power levels. The device chosen for characterization was the 4N25 general-purpose optocoupler. The current transfer ratio, which is an important electrical parameter for optocouplers, was calculated as a function of neutron fluence and gamma dose from the real-time voltage measurements. The resultant radiation effects data was seen to be repeatable and exceptionally finely-resolved. Therefore, the capability at UT TRIGA has been proven competitive with world-class effects characterization facilities. / text