InP shallow-homojunction solar cells

Indium phosphide solar cells with very thin n-type emitters have been made by both ion implantation and metalorganic chemical vapor deposition. Air mass zero efficiencies as high as 18.8 percent (NASA measurement) have been achieved. Although calculations show that, as is the case with GaAs, a heterostructure is expected to be required for the highest efficiencies attainable, the material properties of InP give the shallow-homojunction structure a greater potential than in the case of GaAs. The best cells, which were those made by ion implantation, show open-circuit voltage (V sub oc) of 873 mV, short-circuit current of 357 A/sq m (35.7 mA/sq cm), and fill factor of 0.829. Improvements are anticipated in all three of these parameters. Internal quantum efficiency peaks at over 90 percent in the red end of the spectrum, but drops to 54 percent in the blue end. Other cells have achieved 74 percent in the blue end. Detailed modeling of the data indicates that a high front surface recombination velocity is responsible for the low blue response, that the carrier lifetime is high enough to allow good carrier collection from both the base and the emitter, and that the voltage is base-limited

Put Me To Sleep In Your Heart : And Wake Me Up With Your Love

https://digitalcommons.library.umaine.edu/mmb-vp/2408/thumbnail.jp

High efficiency GaAs-Ge tandem solar cells grown by MOCVD

High conversion efficiency and low weight are obviously desirable for solar cells intended for space applications. One promising structure is GaAs on Ge. The advantages of using Ge wafers as substrates include the following: they offer high efficiency by forming a two-junction tandem cell; low weight combined with superior strength allows usage of thin (3 mil) wafers; and they are a good substrate for GaAs, being lattice matched, thermal expansion matched, and available as large-area wafers

Essential Skills Needed to Prepare LIS Graduates for Careers in Special Libraries: A Survey of Special Librarians

This paper describes a study conducted to identify the skills that special librarians consider most essential in preparing graduates of library and information science programs to work in special libraries. A review of the literature indicates that there is still some debate about what skills can or should be taught in library schools to prepare students for work in special libraries; there is also debate about what types of skills employers of special libraries deem most essential to thrive in these environments. This study used an online survey to solicit the opinions of practicing special librarians on the issue, garnering 709 usable responses. Survey results indicate that a graduate's soft skills may be more beneficial than library science or technical skills, and the highest-ranked skill across the three categories was communication skills. The findings are of primary interest to students interested in careers in special librarianship but may also be beneficial in helping educators and administrators assess LIS curricula

Pacific Coast Groundfish Fishery Assessment and Management: Incorporating Nearshore Surveys into the Fishery Management Framework

The Pacific coast groundfish fishery is a diverse, important and lucrative commercial and recreational fishery. Part of this fishery’s monitoring process includes regular fishery-independent surveys for stock assessment. Although these fishery-independent surveys are cost-effective, they are susceptible to scientific uncertainty, and they do not currently sample in nearshore (water depth < 55 meters) soft-sediment habitats. The NOAA Fisheries Northwest Fisheries Science Center, in collaboration with the Pacific States Marine Fisheries Commission and Oregon State University, is currently sampling young-of-the-year (YOY) groundfishes and other small demersal fishes, along the Newport Hydrographic (NH) Line off the central Oregon coast. A potential use of this survey is to complement the current fishery-independent survey used to inform stock assessments. First, two questions must be addressed: 1) what can nearshore sampling provide to groundfish science and management, and 2) is it practical to incorporate additional nearshore sampling into the current management framework. Answering these questions would help determine whether adding nearshore sampling would improve fishery management. For the purposes of this thesis, “nearshore” is defined as the marine habitats along the continental shelf with water depths shallower than 55 meters. In this analysis, data from bottom trawl and beam trawl surveys were compared within an overlapping nearshore region in order to characterize the juvenile groundfish populations along the continental shelf of Oregon. Examining fish assemblages and environmental variables from both surveys, I found significant differences in fish assemblages, oxygen, temperature, and salinity based on depth, season, and year. Exploring the regulatory framework of the Pacific coast groundfish fishery showed that adding nearshore monitoring to fishery-independent survey designs would be difficult, but it is possible. I also found that the addition of nearshore monitoring would benefit the future designations of groundfish Essential Fish Habitat by providing environmental and biological monitoring of sensitive nursery habitats. By comparing fish community composition and habitat between these surveys and examining current management frameworks, I addressed the overall question of whether monitoring of nearshore habitat would provide a more representative sample of groundfish communities and ecosystem indicators and if it is feasible to do so

Risk Factors for Stunting in Children under the Age of 5 in Rural Guatemalan Highlands

Background: Previously, a study conducted by UNICEF found that malnutrition affects approximately 80% of the indigenous children in Guatemala. Objective: Identify prevalence and risk factors for stunted growth in communities surrounding Lake Atitlán, Guatemala. Methods: Height-for-age measurements of children under the age of five, N = 84, determined stunting prevalence and presumed burden of malnutrition in this region of the Guatemalan highlands. Mothers of a subset of this sample, N = 29, were interviewed to assess factors contributing to stunting. Analysis assessed the following risk factors: inadequate nutrition, increased infectious disease risk, high rate self-report illness, inadequate breastfeeding, and inadequate utilization of prenatal care. Findings: The majority of children under the age of five were stunted (65.6%) and likely malnourished. ANOVA analysis showed significant differences in mean height-for-age Z scores (HAZs) between groups with and without adequate nutrition (F = 7.069, p = 0.013), as well has with and without high rates of self-report illness (F = 6.894, p = 0.014). Both groups with inadequate nutrition (mean HAZs = –2.9, 95% CI = [–3.58, –2.24]) and high rates of self-report illness (mean HAZs = –2.8, 95% CI = [–3.13, –2.38]) had mean HAZs that are indicative of stunting. No other risk factors were associated with stunting. Conclusion: These pilot study results offer methods by which to obtain baseline data for assessing nutritional and public health interventions to improve stunting and malnutrition status as well as the health outcomes of children in rural, indigenous communities

The use of sonic gear to chart locations of natural bars in lower Chesapeake Bay.

An underwater microphone has been developed to detect shell material on the bottom. The system is simple to use and easily constructed. It consists of a microphone encased in a PVC tube and suspended from an A-frame which is towed over the bottom. It is being used along with other methods to chart oyster bottoms in Virginia