Ionizing Particles
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. Investigating Space Radiation Environment Effects on Communication of Razaksat-1
ABSTRACT: This study attempted to identify whether space radiation sources could have affected the communication on RazakSAT-1 that was orbiting in a Low Earth Orbit-Near Equatorial (LEO-NEqO). Data on galactic cosmic rays (GCR), trapped protons, trapped electrons, and solar energetic particles (SEPs) obtained from Space Environment Information System (SPENV
J. Aerosp. Technol. Manag.. Publicado em: 03/05/2018
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2. Aging simulation of the tailings from Stava fluorite extraction by exposure to gamma rays
Abstract Tailings storage facilities are disposal systems for storing the waste products of the mining industry consisting of a slurry mixture made of soil, rock and water that remain after the mineral values have been removed from the patent ore. Tailings dams are supposed to last forever, so after their deposition, tailings can experience aging processes w
REM, Int. Eng. J.. Publicado em: 2017-12
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3. Sensor de corrente transiente para detecção do SET com célula de memória dinâmica
Esta dissertação trata do projeto e avaliação de um novo circuito sensor de corrente com célula de memória dinâmica para a detecção de correntes transientes em circuitos integrados CMOS, provocadas pela incidência de partículas ionizantes. As propostas previamente existentes na literatura são avaliadas e suas deficiências são apontadas. É apre
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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4. Aplicabilidade e validação do Geant4 para fótons e elétrons em radioterapia / GEANT4 applicability and validation to Photons and Electrons in Radiotherapy
Due to the increasing use of ionizing radiation in medical applications, in recent decades, the simulation codes for radiation interacting with matter, based on Monte Carlo Method, have been constantly adapted to applications in medical physics. TheMonte Carlo method is a statisticalmethod of numerical simulation of problems using essentially a sequence of r
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/06/2011
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5. Aplicação de método Monte Carlo para cálculos de dose em folículos tiroideanos
The Monte Carlo method is an important tool to simulate radioactive particles interaction with biologic medium. The principal advantage of the method when compared with deterministic methods is the ability to simulate a complex geometry. Several computational codes use the Monte Carlo method to simulate the particles transport and they have the capacity to s
Publicado em: 2008
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6. Marcos da história da radioatividade e tendências atuais
The first days of radioactivity, the discoveries of X-rays, radioactivity, of alpha- and beta- particles and gamma- radiation, of new radioactive elements, of artificial radioactivity, the neutron and positron and nuclear fission are reviewed as well as several adverse historical marks, such as the Manhattan project and some nuclear and radiological accident
Química Nova. Publicado em: 2007-02
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7. Dependência das propriedades da região-D ionosférica com o ciclo de atividade solar / Dependence of ionospheric D region properties on solar activity cycle
The goal of this work is to provide new clues for a better understanding of the quiescent ionosphere during different solar activity conditions. For that we study the lower ionospheric response to external perturbations, as solar X-rays emitted during flares. We use solar X-ray fluxes provided by GOES satellites, and ionospheric SPA (Sudden Phase Anomalies)
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/07/2006
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8. M-FISH analysis shows that complex chromosome aberrations induced by α-particle tracks are cumulative products of localized rearrangements
Complex chromosome aberrations are characteristically induced after exposure to low doses of densely ionizing radiation, but little is understood about their formation. To address this issue, we irradiated human peripheral blood lymphocytes in vitro with 0.5 Gy densely ionizing α-particles (mean of 1 α-particle/cell) and analyzed the chromosome aberrations
National Academy of Sciences.
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9. Targeted cytoplasmic irradiation with alpha particles induces mutations in mammalian cells
Ever since x-rays were shown to induce mutation in Drosophila more than 70 years ago, prevailing dogma considered the genotoxic effects of ionizing radiation, such as mutations and carcinogenesis, as being due mostly to direct damage to the nucleus. Although there was indication that alpha particle traversal through cellular cytoplasm was innocuous, the full
The National Academy of Sciences.
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10. Do energetic heavy nuclei penetrate deeply into Earth's atmosphere?
We calculate the expected fluxes of cosmic ray nuclei with charge 5 ≤ Z ≤ 28 at various depths in the earth's atmosphere, taking into account the initial charge distribution, ionization loss, and various modes of fragmentation. The flux of surviving heavy nuclei is too low by a factor ≈10-10 to account for the ultra-high-energy Centauro events. We desc
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11. Induction of a bystander mutagenic effect of alpha particles in mammalian cells
Ever since the discovery of X-rays was made by Röntgen more than a hundred years ago, it has always been accepted that the deleterious effects of ionizing radiation such as mutation and carcinogenesis are attributable mainly to direct damage to DNA. Although evidence based on microdosimetric estimation in support of a bystander effect appears to be consiste
The National Academy of Sciences.
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12. Central nervous system radiation syndrome in mice from preferential 10B(n, alpha)7Li irradiation of brain vasculature.
Ionizing radiations were directed at the heads of anesthetized mice in doses that evoked the acute central nervous system (CNS) radiation syndrome. Irradiations were done using either a predominantly thermal neutron field at a nuclear reactor after intraperitoneal injection of 10B-enriched boric acid or 250-kilovolt-peak x-rays with and without previous intr