The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Youngjun Park - One of the best experts on this subject based on the ideXlab platform.
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development of design considerations as a sustainability approach for military protective structures a case study of Artillery fighting position in south korea
Sustainability, 2020Co-Authors: Kukjoo Kim, Youngjun ParkAbstract:Republic of Korea (ROK) military installations are scattered across South Korea, but there is a higher concentration of fortifications in the demilitarized zone (DMZ) and eastern and western coastlines. These facilities range from relatively small structures, such as individual and Artillery fighting positions, to large buildings, such as ammunition depots and command posts. These military installations have a significant thickness of concrete members to provide a high degree of protection against bombs and projectiles. The Korean military will carry out the integration and dismantling of these protection facilities over the next ten years through the Army transformation plan. Such large-scale construction projects have an impact on the environment in terms of the carbon footprint, because building construction and operations account for 36% of the world’s energy use and 40% of energy-related carbon dioxide (CO2) emissions. It is very important to reduce the concrete materials and reinforcement steel during protective structure construction near the DMZ, which is now recognized as one of the most well-preserved areas in the world. In this study, new sustainable design considerations that allow elasto-plastic or plastic design of concrete elements were evaluated using a case study of an Artillery fighting position. The new sustainable design considerations were developed on the basis of mission, enemy, terrain and weather, troops and support available, time and civil considerations (METT + TC) within the context of the current battle situation, as well as protection against near misses. From this study, it was found that new sustainable design considerations provide a reasonable degree of protection that permits good construction practices and maximum structural stability with minimum amount of materials. It was also found that if the new design procedure is used to replace 1000 Artillery positions through the Army transformation plan, the CO2 emissions can be reduced by 476,582.4 tons and the cost reduced by USD 23,829,120.
S Dunn - One of the best experts on this subject based on the ideXlab platform.
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thermal chemical mechanical gun bore erosion of an advanced Artillery system part two modeling and predictions
Wear, 2005Co-Authors: Samuel Sopok, C Rickard, S DunnAbstract:Abstract Thermal–chemical–mechanical gun bore erosion models and predictions are described for an advanced Artillery system and its associated laboratory-firing simulator system. Both high and low contractile chromium electroplated coating types are evaluated. These models and predictions are based on bore erosion theories and mechanisms developed previously by these authors for each of the coating types used in this live fired system and its simulator. These theories and mechanisms are in turn based on associated bore erosion measurements and characterizations acquired previously for this system and it simulator. This Artillery system consists of a cannon, charge, projectile, and additives. Its simulator consists of a vented combustor, charge, and additives. Gun bores typically have an erosion barrier of 0.05–0.50 mm high or low contractile chromium electroplated coating on a nickel–chromium–molybdenum–vanadium high strength gun steel substrate. Gun system firing rates, zones, coating types, and coating thickness vary. Our coating–substrate gun system erosion models were developed from rocket nose-tip and nozzle erosion models. The key calculations of the model are gas and gas-wall thermochemistry, interior ballistics, boundary layer with mass addition, wall temperatures (surfaces, interfaces, micro-pits, pits), and coating–substrate wear and erosion. These erosion models and predictions are used to provide a comprehensive estimate of erosion life and to enable erosion mitigation efforts for each of the coating types used in this advanced Artillery system and its simulator.
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thermal chemical mechanical gun bore erosion of an advanced Artillery system part one theories and mechanisms
Wear, 2005Co-Authors: Samuel Sopok, C Rickard, S DunnAbstract:Abstract Thermal–chemical–mechanical gun bore erosion theories and mechanisms are described for an advanced Artillery system and its associated laboratory-firing simulator system. Both high and low contractile chromium electroplated-coating types are examined. These theories and mechanisms are based on bore erosion measurements and characterizations for each of the coating types used in this live fired system and its simulator. This Artillery system consists of a cannon, charge, projectile, and additives. Its simulator consists of a vented combustor, charge, and additives. Gun bores typically have an erosion barrier of 0.05–0.50 mm high or low contractile chromium electroplated coating on a nickel–chromium–molybdenum–vanadium high strength gun steel substrate. Gun system firing rates, zones, coating types, and coating thickness vary. The main types of measurements and characterizations are of gun system components, firing conditions, gas–wall kinetic thresholds from simulators, during-life erosion metallography and depth, and end-of-life erosion metallography, depth and chemistry. The initial gun bore erosion theories and mechanisms consist of combustion gases traveling down very fine radial cracks in the chromium coating and degrading the substrate steel. These fine cracks result from the plating process. This thermal, diffusion, and chemical degradation weaken the coating–substrate interface. Coating platelets eventually depart forming micro-pits that grow into gun tube condemning macro-pits. These erosion theories and mechanisms are subsequently used to develop erosion models, predictions, and mitigation efforts for each of the coating types used in this advanced Artillery system and its simulator.
Kukjoo Kim - One of the best experts on this subject based on the ideXlab platform.
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development of design considerations as a sustainability approach for military protective structures a case study of Artillery fighting position in south korea
Sustainability, 2020Co-Authors: Kukjoo Kim, Youngjun ParkAbstract:Republic of Korea (ROK) military installations are scattered across South Korea, but there is a higher concentration of fortifications in the demilitarized zone (DMZ) and eastern and western coastlines. These facilities range from relatively small structures, such as individual and Artillery fighting positions, to large buildings, such as ammunition depots and command posts. These military installations have a significant thickness of concrete members to provide a high degree of protection against bombs and projectiles. The Korean military will carry out the integration and dismantling of these protection facilities over the next ten years through the Army transformation plan. Such large-scale construction projects have an impact on the environment in terms of the carbon footprint, because building construction and operations account for 36% of the world’s energy use and 40% of energy-related carbon dioxide (CO2) emissions. It is very important to reduce the concrete materials and reinforcement steel during protective structure construction near the DMZ, which is now recognized as one of the most well-preserved areas in the world. In this study, new sustainable design considerations that allow elasto-plastic or plastic design of concrete elements were evaluated using a case study of an Artillery fighting position. The new sustainable design considerations were developed on the basis of mission, enemy, terrain and weather, troops and support available, time and civil considerations (METT + TC) within the context of the current battle situation, as well as protection against near misses. From this study, it was found that new sustainable design considerations provide a reasonable degree of protection that permits good construction practices and maximum structural stability with minimum amount of materials. It was also found that if the new design procedure is used to replace 1000 Artillery positions through the Army transformation plan, the CO2 emissions can be reduced by 476,582.4 tons and the cost reduced by USD 23,829,120.
Leszek Baranowski - One of the best experts on this subject based on the ideXlab platform.
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numerical testing of flight stability of spin stabilized Artillery projectiles
Journal of Theoretical and Applied Mechanics, 2013Co-Authors: Leszek BaranowskiAbstract:The paper presents results of numerical research on the effect of the twist rate, muzzle velocity, Magnus moment and firing disturbances (cross and range wind) on the stability of flight of a Denel 155 mm Artillery projectile (Assegai M2000 Series) for flat and steep trajectories.
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feasibility analysis of the modified point mass trajectory model for the need of ground Artillery fire control systems
Journal of Theoretical and Applied Mechanics, 2013Co-Authors: Leszek BaranowskiAbstract:The work shows computational results of the effect of a simplified mathematical model of the flight dynamics of a spin-stabilized projectile on the accuracy and speed of calculation parameters for the projectile trajectory (in the entire range of operating quadrant elevation of the barrel and possible perturbations of the conditions firing) to determine an appropriate mathematical model for the automated fire control systems of ground Artillery.
Joss Blandhawthorn - One of the best experts on this subject based on the ideXlab platform.
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Artillery shells over circinus
The Astrophysical Journal, 1997Co-Authors: S Veilleux, Joss BlandhawthornAbstract:The recently identified Circinus galaxy is the nearest (~4 Mpc) Seyfert 2 galaxy known, and we now demonstrate it to be one of the best laboratories for studying the effects of nuclear activity on the surrounding environment. Here we present new imaging Fabry-Perot observations of Circinus that confirm the existence of an ionization cone in this object but also show for the first time a complex of ionized filaments extending radially from the nucleus out to distances of 1 kpc. Arcs suggestive of bow shocks are observed at the terminus of some of these filamentary structures. Most spectacular of all, one of the structures appears to be a scaled-up version of a Herbig-Haro jet. The velocity field of the filaments confirms that they represent material expelled from the nucleus (possibly in the form of "bullets") or entrained in a wide-angle wind roughly aligned with the polar axis of the galaxy. The motions observed across the ionization cone are highly supersonic, so high-velocity shocks are likely to contribute to the ionization of the line-emitting gas. However, it is not clear at present whether shock ionization dominates over photoionization by the Seyfert 2 nucleus. Extrapolation of the filaments to smaller radii comes to within 1'' (~20 pc) of the infrared nucleus, therefore suggesting an active galactic nucleus or nuclear starburst origin for these features. The complex of radial filaments detected in the Circinus galaxy is unique among active galaxies. The frequency of such events is unknown, since only a handful of galaxies have been observed at the sensitivity level of our present observations. The event in the Circinus galaxy may represent a relatively common evolutionary phase in the lives of gas-rich active galaxies during which the dusty cocoon surrounding the nucleus is expelled by the action of jet or wind phenomena.
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Artillery shells over circinus
arXiv: Astrophysics, 1997Co-Authors: S Veilleux, Joss BlandhawthornAbstract:The recently identified Circinus Galaxy is the nearest (about 4 Mpc) Seyfert 2 galaxy known and we now demonstrate to be one of the best laboratories for studying the effects of nuclear activity on the surrounding environment. Here we present new imaging Fabry-Perot observations of Circinus which confirm the existence of an ionization cone in this object but also show for the first time a complex of ionized filaments extending radially from the nucleus out to distances of 1 kpc. Arcs suggestive of bow shocks are observed at the terminus of some of these filamentary structures. Most spectacular of all, one of the structures appears to be a scaled-up version of a Herbig-Haro jet. The velocity field of the filaments confirms that they represent material expelled from the nucleus (possibly in the form of `bullets') or entrained in a wide-angle wind roughly aligned with the polar axis of the galaxy. The motions observed across the ionization cone are highly supersonic, so high-velocity shocks are likely to contribute to the ionization of the line emitting gas. However, it is not clear at present whether shock ionization dominates over photoionization by the Seyfert 2 nucleus. Extrapolation of the filaments to smaller radii comes to within 1 arcsec (about 20 pc) of the infrared nucleus, therefore suggesting a AGN or nuclear starburst origin to these features. The complex of radial filaments detected in the Circinus galaxy is unique among active galaxies. The frequency of such events is unknown since only a handful of galaxies have been observed at the sensitivity level of our present observations. The event in the Circinus galaxy may represent a relatively common evolutionary phase in the lives of gas-rich active galaxies during which the dusty cocoon surrounding the nucleus is expelled by the action of jet or wind phenomena.
