3,282 research outputs found
Gordon Valentine Manley and his contribution to the study of climate change: a review of his life and work
British climatologist and geographer, Gordon Manley (1902â1980), is perhaps best known for his pioneering work on climate variability in the UK, for establishing the Central England Temperature series and, for his pivotal role in demonstrating the powerful relationship between climate, weather, and culture in post-World War II Britain. Yet Manley made many contributions, both professional and popular, to climate change debates in the twentieth century, where climate change is broadly understood to be changes over a range of temporal and spatial scales rather than anthropogenic warming per se. This review first establishes how Manley's work, including that on snow and ice, was influenced by key figures in debates over climatic amelioration around the North Atlantic between 1920s and 1950s. His research exploring historical climate variability in the UK using documentary sources is then discussed. His perspectives on the relationship between climate changes and cultural history are reviewed, paying particular attention to his interpretation of this relationship as it played out in the UK. Throughout, the review aims to show Manley to be a fieldworker and an empiricist and reveals how he remained committed to rigorous scientific investigation despite changing trends within his academic discipline
Keys and Notes on the Buprestidae (Coleoptera) of Michigan
The distribution and dates of adult activity for Michigan buprestids are discussed. Keys to the genera and species, as well as host information are presented for 116 species and one subspecies. Information on collecting techniques, illustrations of genitalia of 14 species, and scanning electron micrographs of certain structures useful in species identification are presented and discussed. In addition, Pachyschelus confusus, a new species, is described from bush clover
Multichannel parametrization of \pi N scattering amplitudes and extraction of resonance parameters
We present results of a new multichannel partial-wave analysis for \pi N
scattering in the c.m. energy range 1080 to 2100 MeV. This work explicitly
includes \eta N and K \Lambda channels and the single pion photoproduction
channel. Resonance parameters were extracted by fitting partial-wave amplitudes
from all considered channels using a multichannel parametrization that is
consistent with S-matrix unitarity. The resonance parameters so obtained are
compared to predictions of quark models
Using Action Research to Determine and Resolve Team Issues for Courseware Developers
A department consisting of four teams of courseware developers and instructors had been experiencing a lack of team cohesiveness as evidenced by the exclusion of individuals and unwillingness to support group goals. Using action research, a collaborative team was formed and data collected using surveys, interviews and observations. The results of the data were fed back to the collaborative team for data analysis. A week long team training session was held that provided for interpretation and clarification of courseware editing procedures. Team structure and location were also modified to allow for closer communications with the customer/supplier
ASSEMBLY DIFFERENTIATION IN CAD SYSTEMS
This work presents a data model for differentiating and sharing assembly design (AsD) information during collaborative design. Joints between parts are an important aspect of assembly models that are often ambiguous when sharing of models takes place. Although various joints may have similar geometries and topologies, their joining methods and process parameters may vary significantly. It is possible to attach notes and annotations to geometric entities within CAD environments in order to distinguish joints; however, such textual information does not readily prepare models for sharing among collaborators or downstream processes such as simulation and analysis. At present, textual information must be examined and interpreted by the human designer and cannot be interpreted or utilized by the computer; thus, making the querying of information potentially cumbersome and time consuming.This work presents an AsD ontology that explicitly represents assembly constraints, including joining constraints, and infers any remaining implicit ones. By relating concepts through ontology technology rather than just defining an arbitrary data structure, assembly and joining concepts can be captured in their entirety or extended as necessary. By using the knowledge captured by the ontology, similar-looking joints can be differentiated and the collaboration and downstream product development processes further automated, as the semantics attached to the assembly model prepares it for use within the Semantic Web
Development and modeling of a low temperature thin-film CMOS on glass
The push to develop integrated systems using thin-film transistors (TFT) on insulating substrates (i.e. glass) has always been limited due to low-mobility semiconducting films such as amorphous and polycrystalline silicon. Corning Incorporated is developing a new substrate material known as silicon-on-glass (SiOG). It is intrinsically better than amorphous and polycrystalline silicon materials due to its single crystal nature of the silicon film. This however does not mitigate the challenges associated with low temperature CMOS process and fabrication. The first generation of TFTs fabricated at RIT showed the potential of SiOG as a viable substrate material, but were plagued by considerable short comings such as high leakage and low transconductance. As part of this study, refinements to TFT processing on SiOG have demonstrated significant improvement to TFT performance and uniformity, showing increase transconductanace/mobility, lower subthreshold swing, tighter VT distributions, and near symmetrical NFET and PFET operation about 0 V. With these improvements minimal steps have been added to the manufacturing process, keeping simple and adoptable by the flat panel display (FPD) industry. Device modeling clearly demonstrates the key areas important to electrical operation, such as dopant activation, interface charge/trap reduction, and workfunction engineering. It addition, modeling and simulation have helped to explain the governing physics of device operation explaining non-ideal effects such as gate induced drain leakage (GIDL) and various mobility degradation mechanism. An overview of device design, process refinements and device operation is presented. Process modifications and resulting benefits are discussed along with CMOS integration on SiOG
Sorghums for Forage in South Dakota
Sorghum is commonly used for forage in South Dakota. In the United States, three-fourths of the total herbage produced by all sorghums is consumed as coarse forage. Forage sorghums include the species that are more valuable for their edible fodder than for their seed. The most promising of these are the black and red seeded amber canes and Sudan grass. Dwarf milo, reterita kafir, shallu and some others are also grown in some localities. It is the purpose of this bulletin to give the results of comparative trials of the producing power of these crops and to give directions for growing the crop based on our experience at the South Dakota Experiment Station farms at Brookings, Cottonwood, Eureka, Highmore and Vivian. In order that the reader may form a correct idea of the value of sorghum, comparisons of various sorghums with such well known crops as corn and millet are inserted
How Costly are Carbon Offsets? A Meta-Analysis of Forest Carbon Sinks
Carbon terrestrial sinks are seen as a low-cost alternative to fuel switching and reduced fossil fuel use for lowering atmospheric CO2. As a result of agreements reached at Bonn and Marrakech, carbon offsets have taken on much greater importance in meeting Kyoto targets for the first commitment period. In this study, meta-regression analysis is used to examine 981 estimates from 55 studies of the costs of creating carbon offsets using forestry. Baseline estimates of costs of sequestering carbon through forest conservation are US260.29 per tC (70.99 per t CO2). Tree planting and agroforestry activities increase costs by more than 200%. When post-harvest storage of carbon in wood products, or substitution of biomass for fossil fuels in energy production, are taken into account, costs are lowest â some 68.44/tC (18.67/t CO2). Average costs are greater, between 1406.60/tC (383.62/t CO2), when appropriate account is taken of the opportunity costs of land. Peer review of the studies increases costs by a factor or 10 or more, depending on the model. The use of marginal cost estimates instead of average cost results in much higher costs for carbon sequestration, in the range of thousands of dollars per tC, although few studies used this method of cost assessment.climate change; Kyoto Protocol, meta-regression analysis, carbon-uptake costs, forest sinks
Creating Carbon Offsets in Agriculture through No-Till Cultivation: A Meta-Analysis of Costs and Carbon Benefits
Carbon terrestrial sinks are often seen as a low-cost alternative to fuel switching and reduced fossil fuel use for lowering atmospheric CO2. To determine whether this is true for agriculture, one meta-regression analysis (52 studies, 536 observations) examines the costs of switching from conventional tillage to no-till, while another (51 studies, 374 observations) compares carbon accumulation under the two practices. Costs per ton of carbon uptake are determined by combining the two results. The viability of agricultural carbon sinks is found to vary by region and crop, with no-till representing a low-cost option in some regions (costs of less than 100-$400/tC). A particularly important finding is that no-till cultivation may store no carbon at all if measurements are taken at sufficient depth. In some circumstances no-till cultivation may yield a âtriple dividendâ of carbon storage, increased returns and reduced soil erosion, but in many others creating carbon offset credits in agricultural soils is not cost effective because reduced tillage practices store little or no carbon.costs of soil carbon credits, conventional and zero tillage systems, carbon accumulation in soil
Light absorption enhancement for ultrathin Cu In1 xGax Se2 solar cells using closely packed 2 D SiO2 nanosphere arrays
2 D closely packed SiO2 nanosphere arrays serving as the photonic structure for light absorption enhancement on top of ultra thin Cu In1 xGax Se2 solar cells are investigated both theoretically and experimentally. It is theoretically demonstrated that whispering gallery modes and high order Mie resonances contribute to the light absorption enhancement for the large spheres and an anti reflection effect is prominent for small ones. The ultra thin CIGSe solar cells achieve the optimum absorption enhancement for the small sphere array with a diameter of 110 nm, contrary to the larger spheres used in Si solar cells. The reason is attributed to the strong parasitic absorption in the AZO ZnO CdS front layers. They absorb mainly in the short wavelength range where the Mie resonances occur. Additionally, it is shown that the 110 nm diameter sphere array exhibits a better angular tolerance than a conventional planar anti reflection layer, which shows the potential as a promising anti reflection structur
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