3,150 research outputs found

    Improved VHF direction finding system

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    Direction finding device operating at very high frequencies requires a loop antenna, mechanical rotation, and large structures. The system is applicable to an unmanned configuration. Direction information is extracted in the form of a direction cosine analog

    Space station experiment definition: Advanced power system test bed

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    A conceptual design for an advanced photovoltaic power system test bed was provided and the requirements for advanced photovoltaic power system experiments better defined. Results of this study will be used in the design efforts conducted in phase B and phase C/D of the space station program so that the test bed capabilities will be responsive to user needs. Critical PV and energy storage technologies were identified and inputs were received from the idustry (government and commercial, U.S. and international) which identified experimental requirements. These inputs were used to develop a number of different conceptual designs. Pros and cons of each were discussed and a strawman candidate identified. A preliminary evolutionary plan, which included necessary precursor activities, was established and cost estimates presented which would allow for a successful implementation to the space station in the 1994 time frame

    Self-supported aluminum thin films produced by vacuum deposition process

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    Self-supported aluminum thin film is produced by vacuum depositing the film on a polyvinyl formal resin film and then removing the resin by radiant heating in the vacuum. The aluminum film can be used as soon as the resin is eliminated

    Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources

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    Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities

    Data appendix to the behavior of LNG vapor clouds: wind-tunnel tests on the modeling of heavy plume dispersion: final report (July 1979-September 1981)

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    CER81-82DEN-RNM25.March 1982.Accompanying final report has title: The behavior of LNG vapor clouds: wind-tunnel tests on the modeling of heavy plume dispersion: final report, July 1979-September 1981.Visual and concentration measurements were made for a large number of continuous ground-level releases of heavy gases into a wind-tunnel boundary layer. These different plumes were not affected by any topographic or building wake influences. The experiments provided a broad coverage of the variable range of source gas specific gravity, source gas flow rate, and approach flow wind speed. From an investigation of the physical similarity between plumes, the permissible modeling distortion in source density, volume flux ratio, and length scale ratio was quantified. The concentration scaling theory which was previously limited to far-field behavior was extended to cover the entire range of plume concentrations. Generalized behavior models were constructed from the laboratory tests. These models were scaled up to atmospheric conditions. The range of atmospheric scenarios to which these laboratory data are applicable is summarized. Measurements on the behavior of transient dense plumes were also obtained.For Gas Research Institute contract no. 5014-352-0203

    Existence theorems in the geometrically non-linear 6-parametric theory of elastic plates

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    In this paper we show the existence of global minimizers for the geometrically exact, non-linear equations of elastic plates, in the framework of the general 6-parametric shell theory. A characteristic feature of this model for shells is the appearance of two independent kinematic fields: the translation vector field and the rotation tensor field (representing in total 6 independent scalar kinematic variables). For isotropic plates, we prove the existence theorem by applying the direct methods of the calculus of variations. Then, we generalize our existence result to the case of anisotropic plates. We also present a detailed comparison with a previously established Cosserat plate model.Comment: 19 pages, 1 figur

    Para investigar a la vejez: desafíos y alternativas durante el trabajo de campo

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    El presente ensayo ofrece una reflexión metodológica sobre las dificultades enfrentadas durante el trabajo de campo cuando los informantes clave son individuos con discapacidades biológicas o mentales, como es el caso de los ancianos. La intención es abrir el debate metodológico acerca de cómo se hace investigación cualitativa en el campo del envejecimiento. La primera parte se centra en el fenómeno de la exclusión de ancianos con mayor grado de deterioro, al seleccionar a los informantes. La segunda parte describe algunas situaciones por las que se dificulta la entrevista con este tipo de ancianos, lo que origina la pérdida de informantes. Por último, se alude a las condiciones de discapacidad biológica o mental que afectan el desarrollo de una entrevista en los cánones tradicionales prescritos en los textos metodológicos y las alternativas para enfrentarlas

    ToF-SIMS and -Raman measurements on laser cleaned bronze archaeological artefacts

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    n this study, ToF-SIMS and -Raman analyses have been employed to assess the feasibility of laser treatments as a selective, non invasive cleaning methodology for archaeological metallic artefacts. A Q-switched Yb:YAG fibre laser, operating at 1064 nm, has been used for the cleaning treatments, carried out in air and 18O rich atmosphere on an ancient bronze coin. The preliminary results show that laser cleaning treatment selectively removes the dangerous oxyhydroxy chlorides corrosion products without affecting the cuprite protective patina grown directly in contact with the metallic surface

    The adverse childhood experiences questionnaire: Two decades of research on childhood trauma as a primary cause of adult mental illness, addiction, and medical diseases

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    Objective. In 1998, Felitti and colleagues published the first study of the Adverse Childhood Experiences-Questionnaire (ACE-Q), a 10-item scale used to correlate childhood maltreatment and adverse rearing contexts with adult health outcomes. This paper qualitatively reviews nearly two decades of research utilizing the ACE-Q, highlighting its contribution to our understanding of the causal roots of common, interlinked comorbidities of the brain and body.Methods. An OVID/PubMed search was conducted for English language articles published before 2016, containing the phrase “Adverse Childhood Experiences” in which the ACE-Q was utilized. Source review included a manual search of bibliographies, resulting in 134 articles, including 44 based on the original ACE-Q study population.Results. ACE-Q research has demonstrated that exposures to adverse childhood experiences converge dose-dependently to potently increase the risk for a wide array of causally interlinked mental illnesses, addictions, and multi-organ medical diseases. The intergenerational transmission of this disease burden via disrupted parenting and insecure rearing contexts is apparent throughout this literature. However, the ACE-Q does not tease out genetic or fetal drug exposure components of this transmission.Conclusions. Adverse childhood experiences and rearing may generate a public health burden that could rival or exceed all other root causes. Translating this information to health-care reform will require strengthening brain-behavioral health as core public and preventative health-care missions. Greater integration of mental health and addiction services for parents should be accompanied by more research into brain mechanisms impacted by different forms and interactions between adverse childhood experiences
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