Thesis (M.S.)--Naval Postgraduate School, 2004. / Title from title screen (viewed Nov. 10, 2004). "June 2004." Electronic book. Includes bibliographical references (p. 49-50). Also issued in paper format.

Thesis (M.S. in Program Management)--Naval Postgraduate School, December 2002. / Thesis advisor(s): David F. Matthews, John F. Phillips. Includes bibliographical references (p. 75-81). Also available online.

The ballistic performance was investigated with rigorous testing of the new armor steel alloy, a tempered variant and a benchmark material. Mechanical testing included Hopkinson pressure bar tests, high temperature, notched tests and standard quasi-static tensile tests. The combination of a commercial prototype cast steel and ballistic testing with NATO standard soft projectiles allowed a uniquely practical perspective when comparing results. The ballistic test procedure reported the same minimum thickness values, for STANAG level 1 kinetic energy threats, than the suggested values of the manufacturer and comparison to the new alloy was thus established. Dynamic material characterization is only accurate within the testing range. Using a single material model to predict critical strength and failure over large strain-rate and temperature ranges is only possible if the material response is consistent. A few scaling problems during specimen testing resulted in a challenging data set with subsequent numerical characterization difficulty. Ballistic performance was however found to correlate well with high strain-rate tensile tests. / Thesis (MEng)--University of Pretoria, 2017. / Materials Science and Metallurgical Engineering / MEng / Unrestricted

Homogenous polymer materials, such as bulk polyester or high-density polyethylene (HDPE), are not commonly associated with armor materials in their raw, unmodified form due to their poor performance at typical ballistic impact velocities. However, projectile penetrations into homogenous polymeric materials have been shown to correlate strongly to the highly temperature-dependent viscoelastic properties such as elastic storage modulus and loss modulus. Ballistic trials conducted at room temperature showed that these two parameters statistically account for a large percentage of the variation in ballistic performance between different polymers. The purpose of this study is to determine the correlation of viscoelastic properties to ballistic resistance when the temperature of the polymer targets is altered above and below room temperature. The ultimate goal is to use these data to determine which materials would perform best against ultra-high velocity impacts, such as the case of micrometeoroid impacts with spacecraft.

The purpose of this investigation was to compare performance and neuromuscular adaptations following ballistic and heavy resistance training. Twenty male university students were divided into a training (n=10) or control group (n=10). Each subject in the training group, by random assignment, trained the elbow extensors of one arm with heavy resistance (HR.) [(5 sets of the maximal weight that could be lifted for 5-7 repetitions (reps.)]; the other with ballistic (BL) actions (5 sets of 6 reps. at 10% of their isometric MVC). Training was done 3 times per week for 17 weeks. Following training, both training HR. and BL regimens produced significant (p≤0.05), but not significantly different increases in ballistic performance peak torque (2.5 vs. 2.7 N·m, peak velocity (1.0 vs. 1.3 rad·s⁻¹), and peak power (32.8 vs. 48.4 W). Similarly, elbow extension movement time decreased to the same extent (-12.5 vs. -6.3 ms; p≤0.05). In contrast, HR training produced significantly greater increases in maximal weight lifting (I RM) (15.8 vs. -0.1 N·m; p≤0.001) and isometric (MVC) strength (8.1 vs. 0.8 N·m; p≤0.01). Electromyography (EMG) recordings of the agonist (AG) triceps brachii indicated significant (p≤0.05) increases in average EMG (AEMG) during I RM, MVC, and ballistic tests (collapsed across training conditions). The only difference between training regimens was the greater 1 RM AEMG after HR. training. Ballistic training resulted in significantly (p≤0.05) greater antagonist ballistic/MVC, and antagonist coactivation (ballistic/MVC) EMG ratios compared to HR. training. Evoked isometric twitch torque and torque-time integral increased only after HR training. Fiber (needle biopsies of triceps) area increases were also significantly (p≤0.001) larger in the HR than the BL arm after training in type I (28.0% vs. -4.7%), type IIa (43.0% vs. 8.3%), and type IIb (41.4% vs. 3.0%) fibers. Dual photon x-ray absorptiometry regional arm analysis revealed that only the HR. arm significantly (p≤0.05) increased in lean mass following training. Heavy resistance training resulted in a significant (p≤0.05) decrease in the percentage of type IIb fibers with a corresponding increase in IIa; whereas ballistic training did not result in any fiber type conversion. These data suggest that although neuromuscular adaptations may differ, either form of training can increase ballistic performance, but only HR. training is effective in increasing muscle size and maximal force during I RM and MVC single joint actions. Heavy Resistance, Ballistic, Torque, Velocity, Power, Electromyography, Evoked Contractile Properties, Fiber Type, and Fiber Area / Thesis / Master of Science (MSc)

No description available.

Explosive volcanic eruptions frequently expel ballistic projectiles, producing a significant proximal hazard to people, buildings, infrastructure and the environment from their high kinetic and thermal energies. Ballistic hazard assessments are undertaken as a risk mitigation measure, to determine probabilities of eruptions occurring that may produce ballistics, identify areas and elements likely to be impacted by ballistics, and the potential vulnerabilities of elements to ballistics. The 6 August, 2012 hydrothermal eruption of Upper Te Maari Crater, Tongariro, New Zealand ejected blocks over a 6 km2 area, impacting ~2.6 km of the Tongariro Alpine Crossing (TAC), a walking track hiked by ~80,000 people a year, and damaging an overnight hut along the track. In this thesis ballistic hazard and risk from Upper Te Maari Crater are assessed through a review of its eruptive history, field and orthophoto mapping of the 6 August ballistic impact distribution, forward modelling and analysis of possible future eruption scenarios using a calibrated 3D ballistic trajectory model, and analysis of the vulnerability of hikers along the impacted Tongariro Alpine Crossing. Orthophoto mapping of the 6 August ballistic impact crater distribution revealed 3,587 impact craters with a mean diameter of 2.4 m. However, field mapping of accessible regions indicated an average of at least four times more observable impact craters and a smaller mean crater diameter of 1.2 m. By combining the orthophoto and ground-truthed impact frequency and size distribution data, it is estimated that approximately 13,200 ballistic projectiles were generated during the eruption. Ballistic impact distribution was used to calibrate a 3D ballistic trajectory model for the 6 August eruption. The 3D ballistic trajectory model and a series of inverse models were used to constrain the eruption directions, angles and velocities. When combined with eruption observations and geophysical observations and compared to the mapped distribution, the model indicated that the blocks were ejected in five variously directed eruption pulses, in total lasting 19 seconds. The model successfully reproduced the mapped impact distribution using a mean initial particle velocity of 200 m/s with an accompanying average gas flow velocity over a 400 m radius of 150 m/s. Assessment of the vulnerability of hikers to ballistics from the August eruption along the TAC utilised the modelled spatial density of impacts and an assumption that an average ballistic impact will cause serious injury or death (casualty) over an 8 m2 area. It is estimated that the probability of casualty ranged from 1% to 16% along the affected track (assuming an eruption during the time of exposure). Future ballistic hazard and vulnerability along the TAC are also assessed through application of the calibrated model. A magnitude larger eruption (than the 6 August) in which 10x more particles were ejected, doubled the affected length of the TAC and illustrated that the probability of casualty could reach 100% in localised areas of the track. In contrast, ballistics ejected from a smaller eruption did not reach the track as was the case with the 21 November 2012 eruption. The calibrated ballistic model can therefore be used to improve management of ballistic hazards both at Tongariro and also, once recalibrated, to other volcanoes worldwide.

Thesis (M.A.)--Auburn University, 2006. / Vita. Includes bibliographical references (p. 259-281). Also available via the Internet.

No description available.

Approved for public release; distribution is unlimited / This thesis examines the decision to assign the Ballistic Missile Defense mission to units of the Colorado and Alaska National Guard. The history of the Nike Ajax, Nike Hercules, Sentinel and Safeguard programs are examined to identify the origins of support for this decision. First-hand sources provide evidence that the National Guard performance in the Nike air defense program is a record of parity and some superiority to equivalent active Army units. Previously documented records of Nike unit inspections and evaluations are included. Perhaps for the first time, the results of a declassified U.S. Army study accepting National Guard participation in the Sentinel/Safeguard missions is reported. Pressures, competing interests and election politics within the context of the American governmental institutions provide insights into the difficult path followed to reach President George W. Bush's 2004 operational declaration, and the uncertainties lying ahead for the Missile-Age Minutemen. The international relations area includes an over-view of the sources of the missile threat to the United States, its friends and allies. With the demise of the Anti-Ballistic Missile Treaty, this thesis gauges the impacts on diplomacy, and shifting priorities and resources within the U.S. Defense structure. The author concludes with personal observations and recommendations. / Major, Colorado Army National Guard