Browsing Departamento de Física by Title
Now showing items 72-91 of 159
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Evaluation of volume change in rectum and bladder during application of image-guided radiotherapy for prostate carcinoma
(AIP Conference Proceedings, 2016-07-07)All prostate cancer patients from Centro Médico Radioterapia Siglo XXI receive Volumetric Modulated Arc Therapy (VMAT). This therapy uses image-guided radiotherapy (IGRT) with the Cone Beam Computed Tomography (CBCT). This ... -
Experimental And Theoretical Analysis Of A Simple Solar Oven In The Climate Of Costa Rica - I
(Elsevier, 1988)Inexpensive and easy to fabricate solar ovens have been made with available materials. One reflector has also been mounted to increase the input radiation on the hot absorbing plate which can be adjusted manually according ... -
Experimental characterization and Monte Carlo simulations of the dose enhancement on the millimeter scale of PAGAT infused with gadolinium
(Elsevier Ltd, 2021-05-03)This study reports on the determination of the K-edge dose enhancement factor achieved in a polymer gel dosimeter based on acrylamide, known as PAGAT, infused with a high concentration of a clinical gadolinium-based compound. ... -
Experimental validation of gallium production and isotope-dependent positron range correction in PET
(Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment vol.814 110-116 2016, 2016-04-01)Positron range (PR) is one of the important factors that limit the spatial resolution of positron emission tomography (PET) preclinical images. Its blurring effect can be corrected to a large extent if the appropriate ... -
Factores que influyen en la forma de la cola de un tsunami
(UNICIENCIA Vol. 23 65-69, 2009)The propagation speed of a tsunami depends on the depth of the ocean in which it propagates. As the tsunami crosses the abyssal plain, it suffers modifications in its form due to change in the depths of the ocean bottom. ... -
Feasibility of dose enhancement assessment: preliminary results by means of Gd-infused polymer gel dosimeter and Monte Carlo study
(Universidad Nacional (Costa Rica), 2018)This work reports the experimental development of an integral Gd-infused dosimeter suitable for Gd dose enhancement assessment along with Monte Carlo simulations applied to determine the dose enhancement by radioactive ... -
First record of Scapholeberis freyi Dumont and Pen- saert, 1983 (Crustacea:Anomopoda: Daphniidae) from Colombia
(Universidad Nacional Mayor de San Marcos, Perú., 2021)From the analysis of plankton samples from a temporary pond of northern Colombia some female specimen of the daphinid cladoceran Scapholeberis freyi Dumont and Pensaert, 1983 was collected. It represents the first report ... -
Generación de un modelo de monitoreo de la contaminación atmosférica por metales pesados en zonas de flujo vehicular, basado en las propiedades magnéticas de biomonitores y polvo urbano
(Tecnológico de Costa Rica, 2023)La contaminación atmosférica urbana es uno de los problemas medioambientales más serios a los que se enfrenta la humanidad ante el rápido crecimiento económico y demográfico. Los efectos en la salud asociados a la contaminación ... -
Gestionando el riesgo por tsunami desde las comunidades
(IV Congreso Nacional de Gestión del Riesgo y Adaptación al Cambio Climático, Heredia 10 y 11 de octubre 2018, 2018)En caso de que la Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE) declare alerta por tsunami, las personas que se encuentran zonas de riesgo deben evacuar antes de la llegada de la primera ola. ... -
Global Magnetohydrodynamic Waves in Stably Stratified Rotating Layers
(University of Leeds UK, 2017-08-23)The 2D shallow water approximation in magnetohydrodynamics is solved, numerically and analytically, for a perfectly conducting fluid on a rotating sphere with a basic state for the toroidal magnetic field: Bφ = B0 sin ... -
Graphene flakes obtained by local electro-exfoliation of graphite with a STM tip
(Physical Chemistry Chemical Physics vol.11 no.19 8061-8068 2017, 2017-02-24)Graphite surfaces can be manipulated by several methods to create graphene structures of different shapes and sizes. Scanning tunneling microscopy (STM) can be used to create these structures either through mechanical ... -
Guía Rápida para Elaborar Planes de Preparativos y Respuesta ante Emergencias por Tsunamis para Hoteles y Cabinas
(Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE), 2020-05)Este documento se enfoca en tsunamis, buscar facilitar a hoteles y cabinas la aplicación de la Norma de Planes de Preparativos y Respuesta ante Emergencias para Centros Laborales o de Ocupación Pública. Requisitos. ... -
Hidrography and river plumes in Golfo Dulce, South Pacific of Costa Rica
(Universidad de Costa Rica, 2015-07)Oceanographic variables at 33 stations distributed in Golfo Dulce, Costa Rica, during the dry and rainy seasons between 2009 and 2010, were analyzed with CTD profiles, where salinity, temperature, sigma-T and currents were ... -
High Specific Capacity of Lithium–Sulfur Batteries with Carbon Black/Chitosan- and Carbon Black/Polyvinylidene Fluoride-Coated Separators
(MDPI, 2022-03-17)In this research, the shuttle effect and the low sulfur activation of lithium–sulfur batteries were mitigated by coating the cathode side of Celgard 2400 separators with mixtures of carbon black/chitosan or carbon ... -
Historical Tsunamis at the Costa Rican Caribbean Coast
(Universidad de Costa Rica, 2021-04-22)Aún cuando los tsunamis son poco frecuentes en el Caribe de Costa Rica, pueden llegar a ser destructivos. En Costa Rica existe la creencia errónea de que no hemos tenido tsunamis. Sin embargo, los autores encontraron ... -
Impact in Costa Rica of the tsunami caused by the Hunga Tonga - Hunga Ha’apai volcano eruption on 15 January 2022
(Springer, 2023-05-12)Hunga Tonga–Hunga Ha’apai had a large eruption (VEI 5–6) on 15 January 2022, which caused a tsunami recorded in all ocean basins. Costa Rica has made many advances in tsunami preparation over the past 9 years since the ... -
Impacto de concentraciones ambientalmente relevantes de nanopartículas de plata en la comunidad microbiana del suelo
(Universidad Nacional (Costa Rica), 2021)La nanotecnología es un área de la ciencia emergente que involucra la ingeniería de partículas nanométricas de diversos materiales (Khare et al., 2014). De acuerdo con la Agencia de Protección Ambiental de Estados Unidos ... -
Importancia de la batimetría de las planicies abisales en la propagación de tsunamis transoceánicos
(Ciencia y tecnología Vol.25,No.1-2 22-33, 2007)The initial form of a tsunami originated by an homogeneous seismic source consists on a simple wave front. While the tsunami propagates in deep water, this simple form suffers several modifications ... -
Inducción de variabilidad genética en una variedad comercial de arroz (Oryza sativa) mediante el uso de radiación gama a partir de la selección in vitro de mutantes tolerantes a ariloxifenoxipropionatos para su uso en el fitomejoramiento del cultivo
(Tecnológico de Costa Rica, 2023)El principio de mejoramiento genético basado en mutaciones consiste en generar cambios hereditarios en el ADN mediante agentes externos. La mutagénesis inducida mediante radiación gamma ofrece una alternativa para desarrollar ... -
Influence of substrate temperature on phase formation in Al-Cr thin films
(Universidad Nacional, Costa Rica, 2000)Thin films (of the order of nm) of Al-Cr alloys were prepared by successive depositions by an electron gun in a vacuum chamber. Three Al and two Cr layers, of thicknesses as to yield the final composition, were de posited ...