Tuning the bandgap of an amorphous sputtered germanium photovoltaic cell.

Microfabricated planar solar cells with an active solar collection area of 0.04cm2 were fabricated on n-type silicon wafers to test the viability of sputtered amorphous thin film photovoltaics for potential use in amorphous multijunction cells or inexpensive laser detectors. Several variants based on the same photovoltaic cell design were produced using amorphous silicon, amorphous germanium, and amorphous germanium-tin to explore band gap depression phenomenon in amorphous thin films that had been previously described in crystalline germanium-tin and germanium-silicon-tin alloys. UV/VIS spectroscopy and Tauc Plot band gap analysis indicated that tin inclusion led to band gap depression of 0.046 eV for every percentage increase in tin content in co-sputtered germanium-tin films. In sputtered amorphous germanium-tin films, increases in average incident photon conversion efficiency of 1.93% for Sn.05Ge.95 and 2.95% for Sn.10Ge.90 as compared to germanium only films were observed. Overall cell efficiency increases were also observed with the inclusion of tin by 0.68% for Sn.05Ge.95 and 0.78% for Sn.10Ge.90 when compared to germanium films. Comparing sputtered germanium films to PECVD deposited amorphous silicon films, the sputtered germanium films displayed significantly lower overall conversion efficiencies and incident photon conversion efficiencies. When comparing to amorphous silicon thin films, improved absorption of longer wavelength radiation in the IR and NIR range was expected with germanium and tin thin films exhibiting band gap depression phenomenon

The Greatest Good

The following is an excerpt from Chapter Two: ”Early Growth“ of The Greatest Good: 100 Years of Forestry in America. Through text and photographs the book explores the European roots of forestry, early forestry education and practice in the United States, the boom in research and production following World War II, and the technologies and practices that will see the profession into the 21st century

Theoretical study of hydrogen microstructure in models of hydrogenated amorphous silicon

We study the distribution of hydrogen and various hydride configurations in realistic models of a-Si:H for two different concentration generated via experimentally constrained molecular relaxation approach (ECMR) [1]. The microstructure corresponding to low ( 20%) concentration of H atoms are addressed and are compared to the experimental results with particular emphasis on the size of H clusters and local environment of H atoms.The linewidths of the nuclear magnetic resonance (NMR) spectrum for the model configurations are calculated in order to compare to the experimental NMR data. Our study shows the presence of isolated hydrogen atoms, small and relatively large clusters with average proton-proton neighbor distance in the clusters around 1.6 to 2.4 Angstrom that have been observed in multiple quantum NMR experiments.Comment: 5 pages, 5 figure

First description of natural Echinococcus multilocularis infections in chinchilla ( Chinchilla laniger ) and Prevost's squirrel ( Callosciurus prevostii borneoensis )

This report describes for the first time the occurrence of alveolar echinococcosis in two exotic rodent species in Europe. A pet chinchilla (Chinchilla laniger) was euthanized due to a painful enlargement of the abdominal cavity, and a Prevost's squirrel (Callosciurus prevostii borneoensis) was found dead in the enclosure of a zoo. At necropsy, extended liver lesions consisting of small vesicles and cysts were observed in the livers of both animals. Histological examination revealed that these cysts were composed of an outer, homogenous, eosinophilic layer and an inner, cellular germinal layer. The cysts from both animals contained numerous protoscolices. The morphological diagnosis of Echinococcus multilocularis metacestode infections was confirmed by molecular mean

Roman Sculpture in Context: Selected Papers in Ancient Art and Architecture, Volume 6

Marice Rose is a contributing author, Body/Culture: Display and Reception of the Farnese Hercules, Chapter 10, pp 177-197. This volume tackles a pressing issue in Roman art history: that many sculptures conventionally used in our scholarship and teaching lack adequate information about their find locations. Questions of context are complex, and any theoretical and methodological reframing of Roman sculpture demands academic transparency. This volume is dedicated to privileging content and context over traditions of style and aesthetics. Through case studies, the chapters illustrate multivariate ways to contextualize ancient objects. The authors encourage Roman art historians to look beyond conventional interpretations; to reclaim from the study of Greek sculpture the Roman originals that are too often relegated to discussions of copies and models ; to consider the multiple, dynamic, and shifting contexts that one sculpture could experience over the centuries of its display; and to recognize that postantique receptions can also offer insight into interpretations of ancient viewers. The collected topics were originally presented in three conference sessions: Grounding Roman Sculpture (Archaeological Institute of America, 2019); Ancient Sculpture in Context (College Art Association, 2017); and Ancient Sculpture in Context II: Reception (College Art Association, 2019).https://digitalcommons.fairfield.edu/visualandperformingarts-books/1022/thumbnail.jp

Air–snowpack exchange of bromine, ozone and mercury in the springtime Arctic simulated by the 1-D model PHANTAS – Part 1: In-snow bromine activation and its impact on ozone

To provide a theoretical framework towards a better understanding of ozone depletion events (ODEs) and atmospheric mercury depletion events (AMDEs) in the polar boundary layer, we have developed a one-dimensional model that simulates multiphase chemistry and transport of trace constituents from porous snowpack and through the atmospheric boundary layer (ABL) as a unified system. This paper constitutes Part 1 of the study, describing a general configuration of the model and the results of simulations related to reactive bromine release from the snowpack and ODEs during the Arctic spring. A common set of aqueous-phase reactions describes chemistry both within the liquid-like layer (LLL) on the grain surface of the snowpack and within deliquesced "haze" aerosols mainly composed of sulfate in the atmosphere. Gas-phase reactions are also represented by the same mechanism in the atmosphere and in the snowpack interstitial air (SIA). Consequently, the model attains the capacity of simulating interactions between chemistry and mass transfer that become particularly intricate near the interface between the atmosphere and the snowpack. In the SIA, reactive uptake on LLL-coated snow grains and vertical mass transfer act simultaneously on gaseous HOBr, a fraction of which enters from the atmosphere while another fraction is formed via gas-phase chemistry in the SIA itself. A "bromine explosion", by which HOBr formed in the ambient air is deposited and then converted heterogeneously to Br₂, is found to be a dominant process of reactive bromine formation in the top 1 mm layer of the snowpack. Deeper in the snowpack, HOBr formed within the SIA leads to an in-snow bromine explosion, but a significant fraction of Br₂ is also produced via aqueous radical chemistry in the LLL on the surface of the snow grains. These top- and deeper-layer productions of Br₂ both contribute to the release of Br₂ to the atmosphere, but the deeper-layer production is found to be more important for the net outflux of reactive bromine. Although ozone is removed via bromine chemistry, it is also among the key species that control both the conventional and in-snow bromine explosions. On the other hand, aqueous-phase radical chemistry initiated by photolytic OH formation in the LLL is also a significant contributor to the in-snow source of Br₂ and can operate without ozone, whereas the delivery of Br₂ to the atmosphere becomes much smaller after ozone is depleted. Catalytic ozone loss via bromine radical chemistry occurs more rapidly in the SIA than in the ambient air, giving rise to apparent dry deposition velocities for ozone from the air to the snow on the order of 10⁻³ cm s^−1 during daytime. Overall, however, the depletion of ozone in the system is caused predominantly by ozone loss in the ambient air. Increasing depth of the turbulent ABL under windy conditions will delay the buildup of reactive bromine and the resultant loss of ozone, while leading to the higher column amount of BrO in the atmosphere. During the Arctic spring, if moderately saline and acidic snowpack is as prevalent as assumed in our model runs on sea ice, the shallow, stable ABL under calm weather conditions may undergo persistent ODEs without substantial contributions from blowing/drifting snow and wind-pumping mechanisms, whereas the column densities of BrO in the ABL will likely remain too low in the course of such events to be detected unambiguously by satellite nadir measurements

Analyse des strategies d'emancipation ou d'adaptation des personnages de romans beurs a la realite des marches sociaux de l'echange

Thesis (MA (Modern Foreign Languages))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: The publication in 1983 of Medhi Charef’s novel Le thé au harem d’Archi Ahmed marked the beginning of Beur literature, a collection of narratives concerning the lives of individuals of North African origin in the French suburbs. The term “beur”, derived from the double inversion of the word “arabe”, would become synonymous with “Maghrebians” and be used to define a cultural movement claiming its uniqueness. Beur writers or those who make use of Beur heroes in their novels reveal, often in autobiographical form, the daily experiences of a marginalized minority living in identical socio-economic conditions, which are sources of conflicts, whether latent or manifest, with the dominant culture. The sensitivity of Beur writers as manifested in their writings enables us to obtain images of the lives of people living in shantytowns or the large conglomerations on the outskirts of French cities. However, this literature provides more than just a simple description of context or situation, since it also contains the verdict of young Beurs on the legitimacy of the established social order and their strategies to transform or to adapt to this order. Work, home, school, politics or affective relations are concrete examples of areas where the individual is faced with an established system of values and norms, inequality of resources and convergent or divergent interests that need to be taken into account during the process of exchange in order to satisfy his/her needs. In this interdisciplinary research we apply the sociological concepts of exchange and conflict theory in order to disclose the strategies used by characters in Beur novels to adapt or free themselves from given conditions of exchange and power configurations on different social markets of exchange