Performance of Hughes GaAs concentrator cells under 1-MeV electron irradiation

Several Hughes gallium arsenide (GaAs) concentrator cells were exposed to 1-MeV electrons at fluences up to 1x10 to the 15th power electrons/sq cm. Performance data were taken after several fluences, at two temperatures, and at concentration levels from 1 to approx. 150x AMO. Data at 1 sun and 25 deg C were taken with an X-25 xenon-lamp solar simulator. Data at concentration were taken using a pulsed solar simulator with the assumption of a linear relationship between short-circuit current and irradiance. The cells are 5 by 5 mm with a 4-mm diameter illuminated area

Literacy at Home: Reading and Writing Activities for Family Time

Reading and writing activities for family time

A Systematic Approach to Manage Clinical Deterioration on Inpatient Units in the Health Care System

The transformation of health care delivery in the United States is accelerating at unbelievable speed. The acceleration is a result of many variables including health care reform as well as the covariation occurring with adjustments in regulations related to resident work hours. The evolving care delivery model has exposed a vulnerability of the health system, specifically in academic medical centers of the United States. Academic medical centers have established a care delivery model grounded and predicated in resident presence and performance. With changes in resident work expectations and reduced time spent in hospitals, an urgent need exists to evaluate and recreate a model of care that produces quality outcomes in an efficient, service driven organization. One potential care model that would stabilize organizations is infusion of APNs with the expanded skills and knowledge to instill practice continuity in the critical care environment. A Medicare demonstration project is proposed for funding an APN expanded role and alteration in the care delivery model. Formative and summative evaluation and impact of such an expanded practice role is included in the proposed project. An evolved partnership between the advanced practice nurse and physician will serve to fill some of the gap currently existing in the delivery system of today. As the complexity and acuity of the patients in the hospital escalates, innovation is demanded to ensure a care model that will foster achievement of the quality outcomes expected and deserved

A Meta-Analysis of Neuropsychological Tests Utilized in Evaluations for Post-Operative Cognitive Dysfunction in Adult Surgery Patients

Cognitive dysfunction post-surgery has a significant impact on patients’ quality of life during recovery and afterward. Several studies have been completed on post-operative cognitive dysfunction (POCD), but since studies are varied in their methodologies and designs a metaanalysis is helpful to synthesize the current available research. The present study took a metaanalysis approach to examine neuropsychological tests most sensitive to POCD in adult surgery patients, and determine implications this would have for developing a battery of tests to evaluate for POCD pre and post-surgery. Although some assessment batteries have been proposed for certain populations (e.g., cardiac patients), little research has been completed on what tests are most sensitive within a general population of patients. Journal articles on POCD were located through medical and psychological research databases. Of the 109 articles that could potentially be included, 24 met inclusion criteria. 192 effect sizes were calculated, with 2,188 participants across all studies. Articles were coded for assessment measures and various factors for studies that included both POCD and non-POCD patients, and effect sizes were determined for each of the neuropsychological tests included in each article using the software Comprehensive Meta- Analysis Professional Version 3. POCD effect sizes were significantly higher in Chinese studies, as compared with studies from other research centers and so Chinese studies were excluded from the final analysis. The final analysis found older adults have more severe cognitive decline due to POCD symptoms, that the most prominent time for symptoms is 7-14 days post-surgery, and that patients have the same pattern of POCD deficits after cardiac surgery as after non-cardiac surgery. The Mini-Mental State Examination (MMSE) was found to be very sensitive to identifying POCD, and tests measuring delayed recall, language, and processing speed were found to be moderately effective in detecting POCD. Implications of these results for postsurgery care of geriatric patients as well as the implications for neuropsychological testing for POCD symptoms are discussed

Performance of epitaxial back surface field cells

Epitaxial back surface field structures were formed by depositing a 10 micron thick 10 Omega-cm epitaxial silicon layer onto substrates with resistivities of 0.01, 0.1, 1.0 and 10 Omega-cm. A correlation between cell open-circuit voltage and substrate resistivity was observed and was compared to theory. The cells were also irradiated with 1 MeV electrons to a fluence of 5 X 10 to the 15th power e/cm2. The decrease of cell open-circuit voltage was in excellent agreement with theoretical predictions and the measured short circuit currents were within 2% of the prediction. Calculations are presented of optimum cell performance as functions of epitaxial layer thickness, radiation fluence and substrate diffusion length

The effects of lithium counterdoping on radiation damage and annealing in n(+)p silicon solar cells

Boron-doped silicon n(+)p solar cells were counterdoped with lithium by ion implantation and the resultant n(+)p cells irradiated by 1 MeV electrons. Performance parameters were determined as a function of fluence and a deep level transient spectroscopy (DLTS) study was conducted. The lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. Isochronal annealing studies of cell performance indicate that significant annealing occurs at 100 C. Isochronal annealing of the deep level defects showed a correlation between a single defect at E sub v + 0.43 eV and the annealing behavior of short circuit current in the counterdoped cells. The annealing behavior was controlled by dissociation and recombination of this defect. The DLTS studies showed that counterdoping with lithium eliminated three deep level defects and resulted in three new defects. The increased radiation resistance of the counterdoped cells is due to the interaction of lithium with oxygen, single vacancies and divacancies. The lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance

Effects of processing and dopant on radiation damage removal in silicon solar cells

Gallium and boron doped silicon solar cells, processed by ion-implantation followed by either laser or furnace anneal were irradiated by 1 MeV electrons and their post-irradiation recovery by thermal annealing determined. During the post-irradiation anneal, gallium-doped cells prepared by both processes recovered more rapidly and exhibited none of the severe reverse annealing observed for similarly processed 2 ohm-cm boron doped cells. Ion-implanted furnace annealed 0.1 ohm-cm boron doped cells exhibited the lowest post-irradiation annealing temperatures (200 C) after irradiation to 5 x 10 to the 13th e(-)/sq cm. The drastically lowered recovery temperature is attributed to the reduced oxygen and carbon content of the 0.1 ohm-cm cells. Analysis based on defect properties and annealing kinetics indicates that further reduction in annealing temperature should be attainable with further reduction in the silicon's carbon and/or divacancy content after irradiation