10 research outputs found

    Alcator C-Mod soft X-ray pulse height analysis system

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (leaves 59-60).A pulse height analysis (PHA) system has been installed on the Alcator C-Mod magnetic confinement fusion experiment. The PHA utilizes a Si(Li) detector to measure soft X-rays in the 1-30 keV range with an energy resolution on the order of 100eV. A FASTComtec MCA-3 multichannel analyzer allows integration times of ims while the PHA supports counting rates of up to 80kHz. The thermal electron temperature is measured from the energy dependence of the intensity of the electron bremsstrahlung spectrum. Measurements of line radiation allows the PHA to identify impurity ions within each plasma shot. The result is a diagnostic that measures thermal electron temperatures while aiding in the indentification of heavy (Z 12) impurities.by Eliseo Gamboa.S.B

    Spatially-resolved x-ray Scattering Experiments.

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    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering (XRTS) is a powerful technique for measuring these parameters in dense plasmas. However, the scattered signal has previously been measured with little or no spatial resolution. This limits XRTS to characterizing homogenous plasmas like steady shocks or isochorically heated matter. This dissertation reports on the development of the imaging x-ray Thomson spectrometer diagnostic for the Omega laser facility, which extends XRTS to the general case of plasmas with one-dimensional structure. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are simultaneously spectrally and spatially resolved along a one-dimensional profile. The technique of imaging x-ray Thomson scattering is applied to produce the first measurements of the spatial profiles of the temperature, ionization state, relative material density, and shock speed of a blast wave in a high-energy density system. A decaying shock is probed with 90 degree scattering of 7.8 keV helium-like nickel x-rays. The spatially-resolved scattering is used to infer the material conditions along the shock axis. These measurements enable direct comparison of the temperature as observed with that inferred from other quantities, with good agreement.PHDApplied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/102287/1/eliseo_1.pd

    Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser

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    We present a cylindrically curved GaAs x-ray spectrometer with energy resolution ΔE/E=1.1104\Delta E/E = 1.1\cdot 10^{-4} and wave-number resolution of Δk/k=3103\Delta k/k = 3\cdot 10^{-3}, allowing plasmon scattering at the resolution limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It spans scattering wavenumbers of 3.6 to 5.2/5.2/\AA\ in 100 separate bins, with only 0.34\% wavenumber blurring. The dispersion of 0.418~eV/13.5μ13.5\,\mum agrees with predictions within 1.3\%. The reflection homogeneity over the entire wavenumber range was measured and used to normalize the amplitude of scattering spectra. The proposed spectrometer is superior to a mosaic HAPG spectrometer when the energy resolution needs to be comparable to the LCLS seeded bandwidth of 1~eV and a significant range of wavenumbers must be covered in one exposure

    The Speed of Sound in Methane under Conditions of the Thermal Boundary Layer of Uranus

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    We present the first direct observations of acoustic waves in warm dense matter. We analyze wavenumber- and energy-resolved X-ray spectra taken from warm dense methane created by laser-heating a cryogenic liquid jet. X-ray diffraction and inelastic free electron scattering yield sample conditions of 0.3±\pm0.1 eV and 0.8±\pm0.1 g/cm3^3, corresponding to a pressure of \sim13 GPa and matching the conditions predicted in the thermal boundary layer between the inner and outer envelope of Uranus. Inelastic X-ray scattering was used to observe the collective oscillations of the ions. With a highly improved energy resolution of \sim50 meV, we could clearly distinguish the Brillouin peaks from the quasi-elastic Rayleigh feature. Data at different wavenumbers were used to obtain a sound speed of 5.9±\pm0.5 km/s, which enabled us to validate the use of Birch's law in this new parameter regime.Comment: 7 pages, 4 figures with supplementary informatio

    Programa de desarrollo para la comuna No. 28

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    Tesis (Economista).- Universidad de Cartagena. Facultad de Ciencias Económicas. Programa de Economía. 1990.El presente estudio tiene por objeto diagnosticar los problemas y necesidades que padece este sector del municipio de cartagena, para asì elaborar estrategias de desarrollo tendientes a dar solución a los problemas que aquejan a la comunidad en un mediano plazo

    La adopción de Tecnologías de Información y Comunicación en las microempresas familiares del municipio Córdoba del estado Táchira (Venezuela)

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    La adopción de Tecnologías de Información y Comunicación puede ayudar a las empresas a obtener ventajas competitivas mediante la diferenciación y al aumento de la productividad en un entorno cada vez más complejo, cambiante e impredecible. Se busca en este sentido describir y caracterizar estos procesos en el caso de las Microempresas Familiares del Municipio Córdoba del Estado Táchira en Venezuela, mediante un estudio exploratorio – descriptivo de tipo cuantitativo. En las empresas estudiadas existe una presencia media – alta en cuanto a la disponibilidad de estos recursos, que contrasta con el muy bajo uso de las mismas en el apoyo a las actividades empresariales

    Speed of sound in methane under conditions of planetary interiors

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    We present direct observations of acoustic waves in warm dense matter. We analyze wave-number- and energy-resolved x-ray spectra taken from warm dense methane created by laser heating a cryogenic liquid jet. X-ray diffraction and inelastic free-electron scattering yield sample conditions of 0.3±0.1 eV and 0.8±0.1 g/cm−3, corresponding to a pressure of ∼13 GPa. Inelastic x-ray scattering was used to observe the collective oscillations of the ions. With a highly improved energy resolution of ∼50 meV, we could clearly distinguish the Brillouin peaks from the quasielastic Rayleigh feature. Data at different wave numbers were utilized to derive a sound speed of 5.9±0.5 km/s, marking a high-temperature data point for methane and demonstrating consistency with Birch's law in this parameter regime. Published by the American Physical Society 202

    XVII International Congress of Control Electronics and Telecommunications: "Advanced Science, Technology and Innovation to move towards a new socio-technical system: Sustainable Social Transformation"

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    Contenido: Approach to the diagnostic of cesarean birth using bio-inspired models. ; Design of a tool in a virtual reality environment to manipulate anatomical models. ; The effect of COVID-19 restrictions on the electricity price forecasting models. ; Depression prevention through artificial intelligence. ; State of the art in Prototypes as complements to the learning of the Colombian Sign Language (LSC). ; A computational proposal for gene expression deterministic analysis in associated disorders to depression and anxiety. ; Evaluation of postural stability from the predictability of the measurement of the center of pressure. ; Psychophysiological Analysis of Sound Stimuli.; Delphi method for the identification of relevant variables in the development of low-power photovoltaic solar projects. ; Socioeconomic impact of a refrigerator powered by a photovoltaic system in La Guajira. ; Energy Efficiency: characteristics that allow the reduction of greenhouse gases in. ; Possibilities for the implementation of a bioreactor from organic waste. ; Energy Potential with Small Hydroelectric Power Plants in Non- interconnected Zones of Colombia. ; Energy Potential in Photovoltaic Solar Solutions in Non-Interconnected Areas of Colombia. ; Photovoltaic system, towards the energy transition from home. ; Blockchain model to increase the transparency of public sector processes. ; Intelligent agricultural irrigation prescription system based on sensor networks and crop modeling. ; Design and implementation of a digital modulation classification system using intelligent algorithms. ; A mobile application proposal to minimize intermediation during agricultural process distribution of products in supply chain. ; Accompanying strategy for the social appropriation of new technologies in vulnerable agricultural communities: case in communities producing Gulupas fruits (Passiflora edulis Sims). ; Predictive model of transparency as an indicator of Public Policies. ; Smart system for recognition of ripening level in blackberry fruits. ; Project-based learning as an alternative methodology for technological education in electronics. ; Design and construction of an automated system for N. ; Four bar mechanisms (FBM) and their Software-Based applications: a reviewFT aquaponic culture of Red Carp and Crespa Lettuce. ; Intelligent search implementation for the construction of states of the art: a python application. ; Indoor and Outdoor propagation models on 5G environments: state of the art. ;The electronic detection of offenders (DOO) in the District Secretary of mobility of Bogotá: a step forward in the configuration of the concept of digital citizenship in Colombia. ; Monitoring through ICT of Mobility: technological collaborative feature to incorporate IoT in a Smart City. ; Characterization model of asphalt mixtures using digital image processing. ; Review: identification of diseases and/or pests in fruit trees through image processing techniques and artificial intelligence. ; VRS applicated to Nasa Yuwe language. ; Application of Pix2Pix for edge reconstruction in images. ; Brushless DC Motor Control System for Active Myoelectric Prosthesis. ; Implementation of a Water Conductivity Measuring System. ; 2 DOF robot programmed with MatLab® (guide and Peter Corke) and Arduino uno for writing alphabetical characters. ; Simulator of the behavior of the center of mass in a quadruped robot. ; Biomimetic prototype for flapping movement of batsContent: Contenido: Approach to the diagnostic of cesarean birth using bio-inspired models. ; Design of a tool in a virtual reality environment to manipulate anatomical models. ; The effect of COVID-19 restrictions on the electricity price forecasting models. ; Depression prevention through artificial intelligence. ; State of the art in Prototypes as complements to the learning of the Colombian Sign Language (LSC). ; A computational proposal for gene expression deterministic analysis in associated disorders to depression and anxiety. ; Evaluation of postural stability from the predictability of the measurement of the center of pressure. ; Psychophysiological Analysis of Sound Stimuli.; Delphi method for the identification of relevant variables in the development of low-power photovoltaic solar projects. ; Socioeconomic impact of a refrigerator powered by a photovoltaic system in La Guajira. ; Energy Efficiency: characteristics that allow the reduction of greenhouse gases in. ; Possibilities for the implementation of a bioreactor from organic waste. ; Energy Potential with Small Hydroelectric Power Plants in Non- interconnected Zones of Colombia. ; Energy Potential in Photovoltaic Solar Solutions in Non-Interconnected Areas of Colombia. ; Photovoltaic system, towards the energy transition from home. ; Blockchain model to increase the transparency of public sector processes. ; Intelligent agricultural irrigation prescription system based on sensor networks and crop modeling. ; Design and implementation of a digital modulation classification system using intelligent algorithms. ; A mobile application proposal to minimize intermediation during agricultural process distribution of products in supply chain. ; Accompanying strategy for the social appropriation of new technologies in vulnerable agricultural communities: case in communities producing Gulupas fruits (Passiflora edulis Sims). ; Predictive model of transparency as an indicator of Public Policies. ; Smart system for recognition of ripening level in blackberry fruits. ; Project-based learning as an alternative methodology for technological education in electronics. ; Design and construction of an automated system for N. ; Four bar mechanisms (FBM) and their Software-Based applications: a reviewFT aquaponic culture of Red Carp and Crespa Lettuce. ; Intelligent search implementation for the construction of states of the art: a python application. ; Indoor and Outdoor propagation models on 5G environments: state of the art. ;The electronic detection of offenders (DOO) in the District Secretary of mobility of Bogotá: a step forward in the configuration of the concept of digital citizenship in Colombia. ; Monitoring through ICT of Mobility: technological collaborative feature to incorporate IoT in a Smart City. ; Characterization model of asphalt mixtures using digital image processing. ; Review: identification of diseases and/or pests in fruit trees through image processing techniques and artificial intelligence. ; VRS applicated to Nasa Yuwe language. ; Application of Pix2Pix for edge reconstruction in images. ; Brushless DC Motor Control System for Active Myoelectric Prosthesis. ; Implementation of a Water Conductivity Measuring System. ; 2 DOF robot programmed with MatLab® (guide and Peter Corke) and Arduino uno for writing alphabetical characters. ; Simulator of the behavior of the center of mass in a quadruped robot. ; Biomimetic prototype for flapping movement of bat
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