7,339 research outputs found

    A study to determine the optimum design of a photographic film for the lunar surface hand-held camera Final report

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    Design, and processing of photographic film for lunar surface hand operated camer

    Experimental active and passive dosimetry systems for the NASA Skylab program

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    Active and passive dosimetry instrumentation to measure absorbed dose, charged particle spectra, and linear energy transfer spectra inside the command module and orbital workshop on the Skylab program were developed and tested. The active dosimetry system consists of one integral unit employing both a tissue equivalent ionization chamber and silicon solid state detectors. The instrument measures dose rates from 0.2 millirad/hour to 25 rads/hour, linear energy transfer spectra from 2.8 to 42.4 Kev/micron, and the proton and alpha particle energy spectra from 0.5 to 75 Mev. The active dosimeter is equipped with a portable radiation sensor for use in astronaut on-body and spacecraft shielding surveys during passage of the Skylab through significant space radiations. Data are transmitted in real time or are recorded by onboard spacecraft tape recorder for rapid evaluation of the radiation levels. The passive dosimetry systems consist of twelve (12) hard-mounted assemblies, each containing a variety of passive radiation sensors which are recoverable at the end of the mission for analysis

    NDE: An effective approach to improved reliability and safety. A technology survey

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    Technical abstracts are presented for about 100 significant documents relating to nondestructive testing of aircraft structures or related structural testing and the reliability of the more commonly used evaluation methods. Particular attention is directed toward acoustic emission; liquid penetrant; magnetic particle; ultrasonics; eddy current; and radiography. The introduction of the report includes an overview of the state-of-the-art represented in the documents that have been abstracted

    Using LaX scintillator in a new low-background Compton telescope

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    The ability of Compton telescopes to perform imaging and spectroscopy in space depends directly on the speed and energy resolution of the calorimeter detectors in the telescope. The calorimeter detectors flown on space-borne or balloon-borne Compton telescopes have included NaI(Tl), CsI(Na), HPGe and liquid organic scintillator. By employing LaX scintillators for the calorimeter, one can take advantage of the unique speed and resolving power of the material to improve the instrument sensitivity and simultaneously enhance its spectroscopic performance and thus its imaging performance. We present a concept for a space-borne Compton telescope that employs LaX as a calorimeter and estimate the improvement in sensitivity over past realizations of Compton telescopes. With some preliminary laboratory measurements, we estimate that in key energy bands, typically corrupted with neutron-induced internal nuclear emissions, this design enjoys a twenty-fold improvement in background rejection

    A performance, energy consumption and reliability evaluation of workload distribution on heterogeneous devices

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    The constant need of higher performances and reduced power consumption has lead vendors to design heterogeneous devices that embed traditional Central Process Unit (CPU) and an accelerator, like a Graphics Processing Unit (GPU) or Field-programmable Gate Array (FPGA). When the CPU and the accelerator are used collaboratively the device computational performances reach their peak. However, the higher amount of resources employed for computation has, potentially, the side effect of increasing soft error rate. This thesis evaluates the reliability behaviour of AMD Kaveri Accelerated Processing Units (APU) executing four heterogeneous applications, each one representing an algorithm class. The workload is gradually distributed from the CPU to the GPU and both the energy consumption and execution time are measured. Then, an accelerated neutron beam was used to measure the realistic error rates of the different workload distributions. Finally, we evaluate which configuration provides the lowest error rate or allows the computation of the highest amount of data before experiencing a failure. As is shown in this thesis, energy consumption and execution time are mold by the same trend while error rates highly depend on algorithm class and workload distribution. Additionally, we show that, in most cases, the most reliable workload distribution is the one that delivers the highest performances. As experimentally proven, by choosing the correct workload distribution the device reliability can increase of up to 90x.A constante necessidade de maior desempenho e menor consumo de energia levou aos fabricantes a projetar dispositivos heterogêneos que incorporam uma Unidade Central de Processameno (CPU) tradicional e um acelerador, como uma Unidade de Processamento Gráfico (GPU) ou um Arranjo de Portas Programáveis em Campo (FPGA). Quando a CPU e o acelerador são usados de forma colaborativa, o desempenho computacional do dispositivo atinge seu pico. No entanto, a maior quantidade de recursos empregados para o cálculo tem, potencialmente, o efeito colateral de aumentar a taxa de erros. Esta tese avalia a confiabilidade das AMD Kaveri "Accelerated Processing Units"(APUs) executando quatro aplicações heterogêneas, cada uma representando uma classe de algoritmos. A carga de trabalho é gradualmente distribuída da CPU para a GPU e o consumo de energia e o tempo de execução são medidos. Em seguida, um feixe de neutrões é utilizado para medir as taxas de erro reais das diferentes distribuições de carga de trabalho. Por fim, avalia-se qual configuração fornece a menor taxa de erro ou permite o cálculo da maior quantidade de dados antes de ocorrer uma falha. Como é mostrado nesta tese, o consumo de energia e o tempo de execução são moldados pela mesma tendência, enquanto as taxas de erro dependem da classe de algoritmos e da distribuição da carga de trabalho. Além disso, é mostrado que, na maioria dos casos, a distribuição de carga de trabalho mais confiável é a que fornece o maior desempenho. Como comprovado experimentalmente, ao escolher a distribuição de carga de trabalho correta, a confiabilidade do dispositivo pode aumentar até 9 vezes

    Introduction to Nuclear Propulsion: Lecture 15 - Nuclear Test Operations

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    The test operation of nuclear power plants, specifically nuclear rockets, bears some interesting similarities to the operation of chemical rocket tests as well as, of course, many differences. A significant feature common to both nuclear and chemical rocket tests is that all the fuel for the entire operation is loaded at the start of the test. As a direct consequence of this fact, the operation of nuclear power plants must be surrounded with adequate safety precautions, as is indeed the case in the operation of chemical rockets, A second direct consequence is that in both types of testing a very thorough and complete checkout is made before starting the test

    Ancient and historical systems

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    Special Libraries, January 1966

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    Volume 57, Issue 1https://scholarworks.sjsu.edu/sla_sl_1966/1000/thumbnail.jp

    Biomedical applications of aerospace-generated technology Quarterly report, 1 Sep. - 30 Nov. 1968

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    Biomedical applications of aerospace generated technolog
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