Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Radiation shielding"”.
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Radiation Shielding of Fusion Systems
… pipe. Future designs should include additional shielding around the beam pipe.
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Radiation shielding calculations by means of MCNPX
Monte Carlo radiation transport calculations were performed to re-evaluate the configuration of the horizontal target bombardment station of the ra-dionuclide production at iThemba LABS. Calculated neutron and photon dose attenuation factors for this shield were compared with those previously …
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Comparative Analysis of Electrodynamic Toroidal Radiation Shielding Configurations
… do can be reduced or mitigated outright through radiation shielding. Because protons and other charged particles comprise most of these radiation particles, strong magnetic fields could be generated around spacecraft to deflect incoming charged radiation particles. This thesis investigates the …
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Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight
… dramatic hazards to human survival.</p> <p>Space radiation hazards outside the protection of the Earth’s magnetosphere can</p> <p>produce both acute and chronic health risks and thus become limiting factors for</p> <p>NASA’s planned mission to Mars by the 2030s. Radiation exposure on a Mars …
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Utilizing Permanent On-Board Water Storage for Efficient Deep Space Radiation Shielding
… is the protection of astronauts from the radiation environment seen in deep space. The most effective way to defend against radiation is increasing the thickness of the shield, however this is limited by strict mass requirements. In order to increase the thickness of the shield, it is …
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Radiation Shielding Design and Radioactive Waste Assessment of Horizontal Compact High Temperature Gas-Cooled Reactor
… Compact HTGR (HC-HTGR). This work addresses shielding, activation analysis and the decommissioning cost assessment as an integrated part of the design process. Reinforced regular and borated concrete were considered as shielding materials for the reactor building and Reactor Cavity Cooling …
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Polyethylene-Based Multifunctional Composite Material for Radiation Shielding, Passive Thermoregulation, and In-Situ Fabrication for Space Exploration
Ionizing radiation sources like energetic electrons, protons, gamma rays, and secondary particles, such as thermal neutrons, are abundant in low Earth orbit (LEO) and deep space environments like lunar and Martian surfaces, where space missions are often conducted. Such sources of space radiation …
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Radiation Shielding calculations using MCNPX transport code for cost optimization of the shielding material to be used at iThemba LABS.
… of producing strong sources of ionising radiation. The most challenging entities, which are part of the indirect ionising radiation, are neutral neutrons and photons. There is a need to protect humans and materials from ionising radiation by providing adequate shielding to attenuate these …
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Development of a Novel Detector Response Formulation and Algorithm in RAPID and its Benchmarking
Solving radiation shielding problems, i.e. deep penetration problems, is a challenging task from both computation time and resource aspects in field of nuclear engineering. This is mainly because of the complexity of the governing equation for neutral particle transport - Linear Boltzmann Equation …
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Exploring poly (2, 5) benzimidazole enhanced with carbon nanotubes for space applications
… explores using polymeric materials for space radiation shielding in low-earth orbit. Shielding against radiation is essential on any space mission. Low atomic number materials, such as hydrogen, have shown to be effective in shielding ionising radiation. However, compared to metallic alloys, …
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Evaluation of nuclear spent fuel dry storage casks and storage facility designs
… an overview of cask types, heat transfer, radiation shielding and storage facility types. Specific criteria are required in the selection of casks and the storage facility to house the casks on site. The selection criteria for casks and the storage facility were determined and technically …
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Natural and artificial orbits around the Martian moon Phobos
… close-range observation, communication, passive radiation shielding, and orbital pitstops for human space flight. These results could be exploited in upcoming missions targeting the exploration of this Martian moon. Furthermore, the new model can provide evidence to support the accretion theory …
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Enabling a permanent human presence beyond low Earth orbit: wearable radiation protection and enhanced science through virtual reality
… low Earth orbit: the development of advanced radiation protection materials and the utilization of virtual reality (VR) for surface exploration. Aligned with NASA's Exploration Systems Development Mission Directorate, the research falls under the exploration capabilities topic of the Advanced …
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Radiation source detection from mobile sensor networks using principal component analysis
… is challenging because of changing background radiation, shielding effects and short collection time, especially when the radioactive materials are moving. The concept of mobile sensor networks is put forward to solve this problem. In this thesis, a small mobile sensor network is established …
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Development of Tools Needed for Radiation Analysis of a Cubesat Deployer Using Oltaris
… of the major ones being the lack of sufficient radiation shielding on the Poly-Picosatellite Orbital Deployer (P-POD). The P-POD attaches to a launch vehicle transporting a primary spacecraft and takes the CubeSats out into their orbit. As the demand for interplanetary exploration grows, there …
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Micro- and millifluidic platforms for imaging agent synthesis
… synthesis equipment to reduce reagent use and radiation shielding costs. My dissertation primarily focuses on addressing the challenges associated with radiometal-based PET radiotracer synthesis. “Click chemistry”, or more specifically Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), was …
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Development, characterization, and application of a charged particle microbeam for radiobiological research
… of this device is to precisely explore the radiation response of biological systems on a cellular and subcellular level, particularly in the area of temporal and spatial effects of radiation on in vitro systems. An accelerator-based 750 keV proton source was characterized and integrated into …
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Effects of Proton Irradiation on the Mechanical and Physical Properties of Carbon Nanotube Based Composites
In this study, the effects of proton irradiation on carbon nanotube (CNT)-epoxy composites are investigated for potential applications in radiation shielding for spacecraft. CNT-epoxy composites were prepared using multiwall and single wall CNTs and exposed to proton beams of energies ranging from …
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Machine-learning models and shielding materials for radiation protection of patients and personnel in ion therapy
… some technological challenges pertaining to the radiation protection of patients and personnel, including 1) the effective implementation of adaptive treatment workflow to account for anatomy changes, 2) optimal tumor coverage with the therapeutic beam to minimize the stray radiation delivered to …
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Implementation and simulation of mobile sensor networks for nuclear radiation detection
… of special nuclear materials, nuclear radiation detection plays an important role in national security applications. However, changing background radiation, shielding effects, and short collection time make radiation detection a challenging problem. Anomaly detection, source …
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