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 88 for “"projectiles"”.
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Investigation of formation and applications of high-speed liquid projectiles
… generation and application of high-speed liquid projectiles. Numerical models were created for a projectile formation by two kinds of launchers, water extruder and water cannon. In the water extruder the kinetic energy of a fast moving piston is transferred to the water load and extrudes the load …
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Floquet theory of electronic stopping processes of projectiles in solids
… for the study of electronic stopping of particle projectiles in crystalline solids. It does not rely on perturbative or linear response approximations. Moreover, it goes beyond nonlinear models for the homogeneous electron gas, which assume ideal metal hosts. The theory exploits a discrete …
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Cavity dynamics of water entry for spheres and ballistic projectiles
… topic is extended to the impact of high-speed projectiles or bullets. Through experimentation the trajectory, cavity size, and forces acting on the projectiles are elucidated. Experimentation coupled with improvements to an existing cavitation model lead to an improved bullet design that forms …
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Impact response of composite structures to rigid and flexible projectiles
… and flexible (uniform and nonuniform bars) projectiles. In the first phase of this study the impact response of imperfect ]aminated cylindrical panels to rigid projectiles is investigated. A 48 degree-of-freedom (DOF) shell finite element based on the classical laminated plate theory, which …
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Micro, meso and macro materials processing using high-speed liquid projectiles
… processing by the impact of high-speed liquid projectiles. The work involved experimental study of generation and applications of high-speed liquid projectiles. The projectiles were generated by the launchers, which used gunpowder as an energy source. The experiments were carried out at the low …
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Behavior of Reinforced Concrete Panels Subject to Impact by Non-deformable Projectiles
… of reinforced concrete (RC) panels against projectiles the contribution of the orthogonal mesh reinforcement has been ignored. In this study the contribution of mesh reinforcement to impact resistance and itseffect on the nature of local damage caused by impact of non-deformable projectiles …
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New Optimal-Control-Based Techniques for Midcourse Guidance of Gun-Launched Guided Projectiles
… guidance and control of gun-launched guided projectiles. Unlike their early counterparts, modern-day gun-launched projectiles are capable of considerable accuracy. This ability is enabled through the use of control surfaces, such as fins or wings, which allow the projectile to maneuver …
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Improvement of Electromagnetic Railgun Barrel Performance and Lifetime by Method of Interfaces and Augmented Projectiles
… usability. The simulated resistivity augmented projectiles were able to mitigate harmful current build-up on the back of a projectile using different conductivity gradients. Within the range of conductivity of aluminum alloys no simulated gradient was able to fully level the current density, …
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Experimental hydrodynamics of spherical projectiles impacting on a free surface using high speed imaging techniques
… thesis looks at the hydrodynamics of spherical projectiles impacting the free surface using a unique experimental WebLab facility. Experiments were performed to determine the force impact coefficients of spheres and then compare obtained results to theories developed by Von-Karman [ 19] and …
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The influence of cylindrical charge geometry on the velocity of blast-driven projectiles in one dimension
The impact of improvised explosive devices (IEDs) on the safety of civilians can be devastating, especially when solid objects are inserted into the explosives. These inserts are propelled at high speed and increase the lethality of an IED detonation. Due to the wide range of possible IED …
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Investigation of ways to make toy projectiles fly farther, straighter, and safer by adopting memory foam
… has been to improve the performances of toy projectiles by modifying their design. While the developed product is required to comply with all applicable safety specifications and regulations, it is also required to satisfy customers. Through brainstorming, over 30 designs of projectile were …
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A Comparative Study Between 6 Degree-of-Freedom Trajectory Model and Modified Point Mass Trajectory Model of Spinning Projectiles
<p>For spinning projectiles, the 6 Degree-of-Freedom model can closely capture their trajectories with high accuracy and details. However, it comes with the drawbacks of long computation time and needing many aerodynamic coefficients which can be hard to obtain. The Modified Point Mass Trajectory …
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A Statistical Theory of Fragmentations of Nuclei by Light Projectiles and Macroscopic Theory to Incorporate Resonances in the Mean Field
Space radiation contains nuclei from hydrogen to nickel in various proportions. These nuclei collide with the shielding materials of spacecrafts causing the emission of secondary radiation, consisting of fragmentation of nuclei of the shielding materials by the incident nuclei, inside the cabin, …
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The Objectiles Guide to Time Travel: Re-Envisioning Building Materials as Narrative-Collecting Object-Projectiles on a Trajectory Through Space-Time
… on a trajectory instead: Objectiles, or object-projectiles. Objectiles are objects on an adventure across space-time to collect as many uses as possible. Rather than remaining associated with one primary use, Objectiles are impressionable, bearing ambiguous traces of all the uses they encounter …
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Numerical study of projectile shape effect on the bumper performance under hypervelocity impact
… on experiments and models involving spherical projectiles. However, observations of collision fragments from ground-based satellite impact experiments have shown that orbital debris are non-spherical in shape. To adjust spacecraft protection to accommodate non-spherical projectiles, a …
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The response of a single wall space structure to impact by cometary meteoroids of various shapes
… for the high-strength, high-density laboratory projectiles. Projectile comparisons based on equal mass, diameter, and total momentum indicate that frangible, low-strength cone projectiles cause significantly higher stresses and larger displacements of the plate at short times after impact than …
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A Comparative Study of Segmented Tungsten Rod Penetration Into a Thick Steel Target Plate
… simulations of tungsten alloy segmented rod projectiles (SRP) penetrating an RHA semi-infinite target plate at high velocities. Penetration experimental data show improved penetration efficiency by the segmented projectiles when compared to monolithic (single solid rod) projectiles. For SRP …
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An investigation of the maximum target material spray velocity produced in the penetration of thin plates by high velocity disks
… and 0.041-cm-thick 1100 Hl4 aluminum plate. The projectiles are made of tungsten and disk shaped. Their diameter is 0.56 em and their thickness is either 0.076 or 0.038 cm. The projectile and target dimensions assure that the one-dimensional assumptions in the theory are valid.. The impact …
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Small scaled reactive materials combustion test facility
… involve high velocity (1-2 km/s), large caliber projectiles directed into blast chambers where overpressure is measured to quantify output. Unfortunately, these existing facilities suffer many issues including high cost per test, which limits the ability to perform true parametric studies, as …
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Resistance of a granular medium to normal impact of a rigid projectile
… of vertical penetration of right-cylindrical projectiles into dry granular soil (Ottawa sand). Rigid projectiles were impacted into the soil at velocities less than 1000 ft/sec. Past theories for predicting penetration in soils have almost exclusively been based upon the impact velocity and …
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