Abrikosov, Gorkov, Dzyaloshinski, Methods of quantum field theory in statistical physics Fetter, Walecka, Quantum theory of many-particle systems T. Schaefer, Quark Matter, hep-ph/0304281. J. Kogut, M. Stephanov, The Phases of QCD, Cambridge University Press (2004). K. Rajagopal, F. Wilczek, The Condensed Matter Physics of QCD, hep-ph/0011333. J. Lattimer and M. Prakash, The Physics of Neutron Stars, astro-ph/0405262. D. Kaplan, Five lectures on effective field theory, nucl-th/0510023.
Introduction: Gamma Knife Perfexion™ delivers 192 Cobalt-60 sources to the focal point (isocenter), and the patient is fixed using a stereotactic frame. In conformal techniques, the width of the penumbra resulting in an out-of-field dose of normal tissue adjacent to the tumor must be accurately determined. The purpose of this study was to calculate the penumbra widths of a single beam and 192 beams for different collimator sizes of the Gamma Knife Perfexion™ using the BEAMNRC/DOSXYZNRC Monte Carlo simulation code and compare the results with EBT3 film dosimetry data.
Material and Methods: To investigate the physical penumbra width (80-20%), the single beam and 192 beam profiles were obtained using the DOSXYZNRC code and EBT3 films located at the isocenter point in a spherical solid water phantom with a diameter of 160 mm.
Results: The results showed that the Gamma Passing Rate (GPR) value for all collimator sizes has a value above 97%. The single-beam penumbra widths obtained from simulation data for 4, 8, and 16 mm collimator sizes along the X-axis were 0.75, 0.77, and 0.87 mm, respectively. The data for 192 beams obtained from the simulation were 2.60, 4.80, and 8.70 mm along the X-axis.
Conclusion: The differences between measured and simulated penumbra widths are in an acceptable range. However, for more precise measurement in the penumbra region with a high dose gradient, a Monte Carlo simulation is recommended.
Medical physics. Medical radiology. Nuclear medicine
The Truyen Tran, Thu Minh Tran, Xuan Tung Nguyen
et al.
This study aims to present the results of anticipation of lightweight concrete durability when exposed to a chloride environment under pre-compressive load. The research employs Keramzit aggregate as the coarse aggregate for lightweight concrete. Following a 28-day curing period in water, the concrete specimens undergo varying levels of pre-compressive stress. Rapid Chloride Permeability Testing is then conducted to ascertain the chloride diffusion coefficient. The study posits a correlation between the chloride diffusion coefficient and precompressive stress levels, drawing from the experimental findings. Furthermore, Monte-Carlo simulation is employed to assess the influence of stochastic variables on the corrosion likelihood of concrete structures using
lightweight aggregates. These stochastic variables encompass the chloride diffusion coefficient, surface chloride concentration, critical chloride concentration, concrete protection layer thickness, and a coefficient contingent
on environmental conditions, to appraise the operational lifespan of lightweight concrete structures.
Engineering (General). Civil engineering (General), Chemical engineering
Aron Bell, Liam Anthony Mannion, Mark Kelly
et al.
The life cycle carbon dioxide equivalent (CO2e) intensity of Power-to-Liquid (PtL) sustainable aviation fuel (SAF) scenarios in Spain are evaluated using a specific, granular, and transparent modelling approach. Post combustion CO2 capture and direct air CO2 capture are considered, in addition to grid and renewable electricity sources. The mass and energy requirements of the PtL system are determined from a mass and energy conserved reaction mechanism and a comprehensive literature review. The SAF yield is constrained by its molecular composition, formulated to meet the physical property specifications for Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) in ASTM D7566 Annex 1. The results of the life cycle assessment (LCA) show large ranges in CO2e intensity of PtL SAF scenarios, from 11 to 101 gCO2e/MJ. The electricity emission factors at which the CO2e intensity of PtL SAFs meet the 70% reduction required under the ReFuelEU Aviation legislation are 112 – 168 gCO2e/kWh for direct air capture and post combustion capture of biogenic CO2. As the average EU grid is approximately 300 gCO2e/kWh, the use of renewable electricity (onsite or power purchase agreement) is therefore essential to achieve the 70% reduction. The carbon intensity of the Madrid to Dublin commercial flight route is analysed, per revenue-passenger-kilometre (RPK), as a specific use case with actual data of Ryanair Boeing 737-800 and 737 MAX 8 aircraft. Compared to the Science Based Targets 1.5°C limit of 3.3 gCO2/RPK, it is shown that sustainable aviation is challenging using PtL SAF, with a best case of 9 gCO2/RPK.