5,760 research outputs found

    Simple non-destructive tests for electroexplosive devices

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    Electrothermal behavior of bridgewire-explosive interface is defined by pulsing electroexplosive device with a safe level of current and examining the resistance variation of bridgewire. Bridgewire provides signal which describes average wire temperature and heat sinking to the explosive and enclosure

    Electrothermal follow display apparatus for electroexplosive device testing

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    A self-balancing bridge for ascertaining the electrothermal and nonlinear behavior of an electroexplosive device is described. A sinusiodal current is passed through the device which provides a signal in the form of a unique Lissajous display. The display can be qualitatively evaluated and abnormal units can be readily detected

    Nondestructive testing of insensitive electroexplosive devices by transient techniques

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    Nondestructive testing of insensitive electroexplosive devices by transient technique

    Generation of Narrow High Current Pulses

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    Many of the fundamental factors affecting the initiation of electroexplosive devices have not been satisfactorily explained. A description of a narrow, high current pulse generator capable of pulses 4 microseconds wide and 94 amperes is given which will be useful in the study of the initiation mechanism

    Terminated capacitor discharge firing of electroexplosive devices

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    Terminated capacitor discharge firing of electroexplosive device

    Half-sine wave pulse firing of electroexplosive devices

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    Half-sine wave pulse firing of electroexplosive device

    Quality aware selective ECC for approximate DRAM

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    Approximate DRAMs are DRAM memories where energy saving techniques have been implemented by trading off bit-cell error rate with power consumption. They are considered part of the building blocks in the larger area of approximate computing. Relaxing refresh rate has been proposed as an interesting solution to achieve better efficiency at the expense of rising error rate. However, some works have demonstrated that much better results are achieved if at word-level some bits are retained without errors (i.e. their cells are refreshed at nominal rate), resulting in architectures using multiple refresh rates. In this paper we present a technique that can be applied to approximate DRAMs under reduced refresh rate. It allows to trim error rate at word-level, while still performing the refresh operation at the same rate for all cells. The number of bits that are protected is configurable and depends on output quality degradation that can be accepted by the application

    Customizable vector acceleration in extreme-edge computing. A risc-v software/hardware architecture study on VGG-16 implementation

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    Computing in the cloud-edge continuum, as opposed to cloud computing, relies on high performance processing on the extreme edge of the Internet of Things (IoT) hierarchy. Hardware acceleration is a mandatory solution to achieve the performance requirements, yet it can be tightly tied to particular computation kernels, even within the same application. Vector-oriented hardware acceleration has gained renewed interest to support artificial intelligence (AI) applications like convolutional networks or classification algorithms. We present a comprehensive investigation of the performance and power efficiency achievable by configurable vector acceleration subsystems, obtaining evidence of both the high potential of the proposed microarchitecture and the advantage of hardware customization in total transparency to the software program

    Griscelli syndrome type 2: long-term follow-up after unrelated donor bone marrow transplantation

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    Griscelli syndrome (GS) is a rare autosomal recessive disease characterized by silvery hair ('partial albinism'). Three forms exist; GS type 2 (GS2), the most common one, is characterized by severe primary immunodeficiency with acute episodes of hemophagocytic lymphohistiocytosis (HLH) which may be fatal in the absence of hematopoietic stem cell transplantation. A 5-year-old boy with HLH was referred to us because of silvery-gray hair present since birth. Abnormal pigment clumps were observed in the medulla of hair shafts on light microscopy. Electron microscopy of a skin biopsy revealed melanosomes in melanocytes, but not in keratinocytes. Leukocytes were devoid of intracytoplasmic granules on blood smear. Neurological signs were absent. Genotyping revealed a homozygous haplotype for polymorphic markers linked to the RAB27A locus, but no RAB27A mutation. A diagnosis of GS2 was established. The patient received bone marrow transplantation (BMT) from an unrelated donor, and after 72 months he did not show relapse of HLH. The long, uneventful follow-up supports the use of BMT from an unrelated donor if transplantation from a relative is not possible

    How the internet increases modern contraception uptake: evidence from eight sub-Saharan African countries

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    Background Sub-Saharan African (SSA) countries have the highest worldwide levels of unmet need for modern contraception. This has led to persistently high fertility rates in the region, rates which have had major adverse repercussions on the development potential there. Family planning programmes play a key role in improving the uptake of modern contraception, both by fostering women’s health and by lowering their fertility. Increasing awareness of contraception benefits is a major component of such programmes. Here, we ask whether internet access can bridge the gap between women’s need for modern contraception and women’s uptake of the same. Methods We use a compendium of data for 125 242 women, aged 15–49, from the Demographic Health Survey, Akamai and International Communication Union data, covering eight SSA countries, for the period 2014–2019. We apply a Two-Stage Least Square model, using as instruments for individual internet exposure the distance to the main server in the country and whether the backbone network in the country has been connected to at least one submarine cable. Results Internet exposure, measured as women access the internet at least monthly (almost daily), is associated with a positive, 11.4% (95% CI 10.6% to 12.2%) (53.8% (95% CI 13.4% to 94.1%)), increase in modern contraception uptake. Education is an important moderator. Poorly educated women benefit the most from internet exposure. Discussion Internet exposure appears to have significantly increased the uptake of modern contraception among sub-Saharan women. The poorly educated appear particularly to benefit. There are two mechanisms at play: the internet increases women’s knowledge of contraception; and, in parallel, fosters their empowerment
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