1,901 research outputs found

    Solid state, CCD-buried channel, television camera study and design

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    An investigation of an all solid state television camera design, which uses a buried channel charge-coupled device (CCD) as the image sensor, was undertaken. A 380 x 488 element CCD array was utilized to ensure compatibility with 525 line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (a) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (b) techniques for the elimination or suppression of CCD blemish effects, and (c) automatic light control and video gain control techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a design which addresses the program requirements for a deliverable solid state TV camera

    The world wide spread of space technology

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    Space technological capabilities and developments in US, USSR, Western Europe, Japan, China, and developing nation

    Organizational learning in development assistance: a comparative analysis of six tree-planting projects in Kenya

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    Most community-level development assistance projects fail to achieve their stated objectives. With frustrating regularity, new projects repeat the mistakes that defeated their predecessors. If development assistance organizations are to become effective, they must develop the capacity to learn from their experiences and the experiences of others. There is evidence that community-level forestry projects sponsored by several national and international organisations in Kenya have begun to develop this capacity. I propose to undertake a comparative analysis of six Kenyan efforts (Kenya Wood fuel Development Program, Kenya Renewable Energy Development Project, Rural Afforestation Extension Scheme, CARE Agro-forestry Extension Project, the Greenbelt Movement, and the Kenya Energy Non-Governmental Organization Association), to determine what, these organizations have learned about the design and implementation of sustainable projects and how they learned it

    Cross-pollination: inter-organizational learning in Kenyan tree-planting programs

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    Development assistance organizations working on the same problems in the same region have much to learn from each other's experiences. This preliminary analysis examines inter-organizational learning, as part of a larger study of organizational learning in development assistance. A comparative analysis of tree-planting programs in Kenya found that most formal mechanisms to foster inter-organizational learning achieved only limited success. It is argued that the failures of these mechanisms can be ascribed to their reliance on the participation of program managers, who lack the time, resources, or incentives to participate beyond a superficial level. However, the analysis also reveals that a great deal of information and expertise is shared among these organizations in informal ways, through collegial networks and cooperation among extension staffs. It is recommended that formal mechanisms for inter-organizational learning be adjusted to reflect their limitations, and that informal mechanisms be recognized and encouraged

    Mechanisms of Surviving Burial: Dune Grass Interspecific Differences Drive Resource Allocation After Sand Deposition

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    Sand dunes are important geomorphic formations of coastal ecosystems that are critical in protecting human populations that live in coastal areas. Dune formation is driven by ecomorphodynamic interactions between vegetation and sediment deposition. While there has been extensive research on responses of dune grasses to sand burial, there is a knowledge gap in understanding mechanisms of acclimation between similar, coexistent, dune-building grasses such as Ammophila breviligulata (C3), Spartina patens (C4), and Uniola paniculata (C4). Our goal was to determine how physiological mechanisms of acclimation to sand burial vary between species. We hypothesize that (1) in the presence of burial, resource allocation will be predicated on photosynthetic pathway and that we will be able to characterize the C3 species as a root allocator and the C4 species as leaf allocators. We also hypothesize that (2) despite similarities between these species in habitat, growth form, and life history, leaf, root, and whole plant traits will vary between species when burial is not present. Furthermore, when burial is present, the existing variability in physiological strategy will drive species-specific mechanisms of survival. In a greenhouse experiment, we exposed three dune grass species to different burial treatments: 0 cm (control) and a one-time 25-cm burial to mimic sediment deposition during a storm. At the conclusion of our study, we collected a suite of physiological and morphological functional traits. Results showed that Ammophila decreased allocation to aboveground biomass to maintain root biomass, preserving photosynthesis by allocating nitrogen (N) into light-exposed leaves. Conversely, Uniola and Spartina decreased allocation to belowground production to increase elongation and maintain aboveground biomass. Interestingly, we found that species were functionally distinct when burial was absent; however, all species became more similar when treated with burial. In the presence of burial, species utilized functional traits of rapid growth strategy, although mechanisms of change were interspecifically variable

    Thermal stability of sputter-deposited 330 austenitic stainless-steel thin films with nanoscale growth twins

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    We have explored the thermal stability of nanoscale growth twins in sputter-deposited 330 stainless-steel (SS) films by vacuum annealing up to 500 °C. In spite of an average twin spacing of only 4 nm in the as-deposited films, no detectable variation in the twin spacing or orientation of twin interfaces was observed after annealing. An increase in the average columnar grain size was observed after annealing. The hardness of 330 SS films increases after annealing, from 7 GPa for as-deposited films to around 8 GPa for annealed films, while the electrical resistivity decreases slightly after annealing. The changes in mechanical and electrical properties after annealing are interpreted in terms of the corresponding changes in the residual stress and microstructure of the films

    Two-neutron knockout from neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si

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    Two-neutron knockout reactions from nuclei in the proximity of the proton dripline have been studied using intermediate-energy beams of neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si. The inclusive cross sections, and also the partial cross sections for the population of individual bound final states of the 32^{32}Ar, 28^{28}S and 24^{24}Si knockout residues, have been determined using the combination of particle and γ\gamma-ray spectroscopy. Similar to the two-proton knockout mechanism on the neutron-rich side of the nuclear chart, these two-neutron removal reactions from already neutron-deficient nuclei are also shown to be consistent with a direct reaction mechanism.Comment: Phys. Rev. C, rapid communication, in pres
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