41 research outputs found

    Transformer regulated self-stabilizing chopper

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    A self-stabilizing voltage regulator is described. Direct current voltage regulation employing a series transistor rendered conductive during various portions of a cycle is controlled by saturation of an autotransformer. The constant volt-second capacity of the transformer provides conduction time inverse to the input voltage whereby average output voltage is maintained constant. Conduction commenced in response to short gate signals, and resistor feedback for degenerative turn-off of the transistor was after transformer saturation. Standard output filters are also included

    Parasitic suppressing circuit

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    A circuit for suppressing parasitic oscillations across an inductor operating in a resonant mode is described. The circuit includes a switch means and resistive means connected serially across the inductor. A unidirectional resistive-capacitive network is also connected across the inductor and to the switch means to automatically render the switch means conducting when inductive current through the inductor ceases to flow

    Nondissipative dc to dc regulator-converter study third quarterly report, 15 dec. 1964 - 15 aug. 1965

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    Nondissipative dc to dc voltage regulator frequency converte

    Nondissipative dc to dc regulator-converter study, phase I Final project report, 15 Jun. 1964 - 31 Dec. 1965

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    Breadboard testing of chopper and booster regulators for application to DC-to-DC regulator-converte

    Multipurpose acoustic networks in the integrated arctic ocean observing system

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    The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This activity will be driven by increased demand for energy and the marine resources of an Arctic Ocean accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism, and search and rescue will increase the pressure on the vulnerable Arctic environment. Technologies that allow synoptic in situ observations year-round are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual, and decadal scales. These data can inform and enable both sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. In this paper, we discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic, and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings, and vehicles. We support the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary in situ Arctic Ocean observatory

    Examining the role of genetic risk and longitudinal transmission processes underlying maternal parenting and psychopathology and children’s ADHD symptoms and aggression: utilizing the advantages of a prospective adoption design

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    Although genetic factors may contribute to initial liability for ADHD onset, there is growing evidence of the potential importance of the rearing environment on the developmental course of ADHD symptomatology. However, associations between family-level variables (maternal hostility, maternal depressive symptoms) and child behaviors (developmental course of ADHD and aggression) may be explained by genes that are shared by biologically related parents and children. Furthermore, ADHD symptoms and aggression commonly co-occur: it is important to consider both simultaneously to have a better understanding of processes underlying the developmental course of ADHD and aggression. To addresses these issues, we employed a longitudinal genetically sensitive parent–offspring adoption design. Analyses were conducted using Cohort I (n = 340) of the Early Growth and Development Study with cross-validation analyses conducted with Cohort II (n = 178). Adoptive mother hostility, but not depression, was associated with later child ADHD symptoms and aggression. Mothers and their adopted children were genetically unrelated, removing passive rGE as a possible explanation. Early child impulsivity/activation was associated with later ADHD symptoms and aggression. Child impulsivity/activation was also associated with maternal hostility, with some evidence for evocative gene-environment correlation processes on adoptive mother depressive symptoms. This study provides novel insights into family-based environmental influences on child ADHD and aggression symptoms, independent of shared parental genetic factors, implications of which are further explicated in the discussion

    An updated analysis of safety climate and downstream outcomes in two convenience samples of U.S. fire departments (FOCUS 1.0 and 2.0 survey waves)

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    Abstract Background The Fire service Organizational Culture of Safety (FOCUS) survey is an assessment tool comprised of psychometrically validated metrics of safety climate, safety behavior, and downstream outcomes (organizational and injury) that are specific to the U.S. fire and rescue service. Methods This analysis consists of a descriptive summary of two independent survey waves (FOCUS 1.0 and 2.0). The fire departments included in these survey waves were from convenience sampling (n 1.0 = 275; n 2.0 = 170). In addition to department level characteristics, we examined individual level characteristics for firefighters and EMS providers in participating departments (n 1.0 = 22,719; n 2.0 = 16,882). We conducted regression analyses to examine the associations between safety climate and safety behaviors, organizational outcomes, and safety outcomes. All analyses were stratified by organization type (career, volunteer). Results Our analysis indicated that a majority of respondents were males (90.7%FOCUS 1.0; 90.4%FOCUS 2.0), non-officers (68.4%FOCUS 1.0; 66.4%FOCUS 2.0), and non-Hispanic Whites (70.8%FOCUS 1.0; 69.5%FOCUS 2.0). For both samples there was a higher prevalence of injuries among individuals in career departments (n FOCUS 1.0 = 3778 [17.5%]; n FOCUS 2.0 = 3072 [18.7%]) than volunteer departments (n FOCUS 1.0 = 103 [8.8%]; n FOCUS 2.0 = 34 [7.4%]). We observed an approximate 10-point difference between the mean scores of Management Commitment to Safety for career and volunteer departments in both samples. We observed associations for two organizational outcomes, Safety Behavior and Job Satisfaction, with Management Commitment to Safety and Supervisor Support for Safety overall and when stratified by organization type. We observed a decrease in the odds of injuries associated with a one-unit increase in Management Commitment to Safety (OR1.0 overall: 0.98, 95% CI 0.97–0.99; OR2.0 volunteer: 0.90, 95% CI 0.85–0.95) and Supervisor Support for Safety (OR1.0 overall: 0.95, 95% CI 0.93–0.97; OR1.0 career: 0.95, 95% CI 0.92–0.98). Conclusions From our current study, and a prior analysis of a geographically stratified random sample of U.S. fire departments, we identified that from all the organizational outcomes, job satisfaction was most consistently associated with FOCUS safety climate. Further, firefighters in our samples consistently rated Supervisor Support for Safety higher than Management Commitment to Safety. Future interventions should support fire departments in improving their departmental Management Commitment to Safety and maintaining their Supervisor for Safety
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