Similar projectile point types were used by groups living over a wide geographic region in central and southern Arizona and southwestern New Mexico during the thirteenth and fourteenth centuries A.D. Substantial changes that occurred in southeastern Arizona at this time include population aggregation, the arrival of northern migrant groups, and an increase in obsidian use. An analysis focusing on two sub-regions, the Tucson Basin and the San Pedro Valley, was conducted to explore how social, technological and environmental factors influenced projectile point technology during the Classic period (A.D. 1150–1450) in southeastern Arizona. Projectile point metric and morphological attributes and obsidian source data were used for comparisons within both of the sub-regions. Despite differences in social relations, obsidian exchange networks, and access to large game, comparisons between sites in the northeastern and northwestern Tucson Basin did not reveal significant differences in projectile point types. However, a good deal of variation in base morphology is evident regardless of type among the Tucson Basin sites. Projectile points from Kayenta enclaves in the Lower San Pedro Valley are overwhelmingly made of obsidian, but do not possess significantly different attributes from those used by local groups. Notable variation was seen in the small sample from the Upper San Pedro Valley, which may be attributed to the lack of influence from groups living to the north. Overall, the similarities in projectile point forms correspond with the growth of social networks during the Classic period. Although the small size of these points restricts their usefulness for signaling group identity, variation in base morphology, serrated blade edges, and other small details may continue to inform on the learning traditions or cultural preferences of groups in the region. Future research should expand the study area to include the Upper Gila region of New Mexico, where groups were living close to the extensive Mule Creek obsidian source.

Critical velocity is defined as projectile striking velocity that causes instantaneous rupture of the specimen under transverse impact. The main goal of this dissertation was to determine the critical velocities of a Twaron^® 2040 warp yarn impacted by different round indenters. Special attention was placed to develop models to predict the critical velocities when transversely impacted by the indenters. An MTS 810 load frame was utilized to perform quasi-static transverse and uniaxial tension experiments to examine the stress concentration and the constitutive mechanical properties of the yarn which were used as an input to the models. A gas/powder gun was utilized to perform ballistic experiments to evaluate the critical velocities of a Twaron^® 2040 warp yarn impacted by four different type of round projectiles. These projectiles possessed a radius of curvature of 2 μm, 20 μm, 200 μm and 2 mm. The results showed that as the projectile radius of curvature increased, the critical velocity also increased. However, these experimental critical velocities showed a demonstrated reduction as compared to the classical theory. Post-mortem analysis via scanning electron microscopy on the recovered specimens revealed that the fibers failure surfaces changed from shear to fibrillation as the radius of curvature of the projectile increased. To improve the prediction capability, two additional models, Euler-Bernoulli beam and Hertzian contact, were developed to predict the critical velocity. For the Euler–Bernoulli beam model, the critical velocity was obtained by assuming the specimen ruptured instantaneously when the maximum flexural strain reached the ultimate tensile strain of the yarn upon impact. On the other hand, for the Hertzian contact model, the yarn was assumed to fail when the indentation depth was equivalent to the diameter of the yarn. Unlike Smith theory, the Euler-Bernoulli beam model underestimated the critical velocity for all cases. The Hertzian model was capable of predicting the critical velocities of a Twaron^® 2040 yarn transversely impacted by 2 μm and 20 μm round projectiles.

Projectile points/ knives (PPKs) are categorized by morphology, also called typology, and associated with cultural periods. A total of 64 PPKs in collections in the Archaeology Lab at East Tennessee State University were curated as untyped and without provenience. They were allegedly collected from ground surveys in Upper East Tennessee, but without archaeological context research had not been prioritized. The importance of such research lies in the fact that few publications exist on the region of Upper East Tennessee and many reference books on lithic typology portray PPKs through illustrations of the ideal morphology of each type. The challenge herein is that the lithic technologies excavated by archaeologists are typically used, worn, broken, or abandoned. A comparative collection of projectile points found in the field from the region of Upper East Tennessee is a valuable research resource. The 64 PPKs yielded 25 typologies that are, indeed, published from Upper East Tennessee and show variability from resharpening, wear, and other means. The comparative collection is curated at the East Tennessee State University Archaeology Lab at Valley Brook.

This paper presents a refined methodology for distinguishing the stone points of arrows from the stone points of spear thrower darts in archaeological assemblages from the Great Basin. The methodology was developed from a sample of 111 complete stone points collected during the archaeological reconnaissance and testing of the Malheur National Wildlife Refuge, Harney County, Oregon, 1971-1974. The points were measured for five metric variables and frequency histograms of each variable were generated by computer. The effectiveness of each variable as an index of functional class (i.e., arrow point vs. dart point) was judged on the basis of the apparent bimodality of its curve and the t-test. The variables of weight and neck width showed significant bimodality, confirming the work of previous researchers. A new variable, stem thickness, also showed significant bimodality. All three can be considered useful indices of functional class. They also appear to be functionally independent. An attempt was made at developing a multivariable index of point function, using a multivariable clustering analysis, the K-means test. Results of the K-means test were inconclusive but showed promise for further development.

This thesis presents the design and construction of a micro-scale, air powered, impact testing device for use in Virginia Tech's Biological and Bio-inspired Materials Laboratory. A brief overview of current projectile impact testers is presented along with motivation for the fabrication of a new testing system capable of firing a projectile with a maximum diameter of 0.5 mm at velocities ranging from 20 to 50 m/s. Initial design calculations and analysis were performed to optimize barrel length, projectile size, and air pressure for desired velocity ranges. Computer aided design was then utilized to create a digital model of the entire system before production began on the device. Within the scope of this project was the development of a large-scale projectile impact tester as a proof of concept of the system's design that would later be utilized by other researchers as well as the micro-scale tester which carried over the lessons learned and design improvements from the larger device. The culmination of the project was the testing of biological samples (sea urchin spine cross sections) to prove the viability of the device and highlight its research niche. Future use cases and design improvements of the small-scale impact tester were also investigated as part of this thesis work. / Master of Science / This thesis encompasses the design and fabrication of both a large-scale projectile impact tester as a proof of concept design as well as a micro-scale version that carries over many of the design elements of the large version but is designed to fire projectiles for small scale biological material tests. Also included as part of this thesis is a breakdown of the various impact testers currently available within research to show why this project was necessary. The project culminated in simple impact studies of sea urchin spines to showcase the capabilities of the impact tester in its current form as well as to outline some of the expanded properties that could be determined with simple experimental setup changes. From this impact, study it was determined that sea urchin spines are a leading candidate in the formulation of bio-inspired impact resistant ceramic foams as they have excellent energy absorption properties during dynamic loading. The calcite foam structure of the sea urchin spines proved to have better impact absorption capabilities in comparison to many current engineering materials used for impact resistance. The final part of this thesis is a brief overview of the planned future use cases of the device.

This thesis primarily addresses the quantities and distributions of Fremont projectile points in the Parowan Valley. First, I review previous research performed in Parowan Valley and outline currently accepted projectile point analysis and typology methods. I also review ethnographic data surrounding the function and value of projectile points. Then, I provide the results of an analysis of all projectile points in the Parowan Valley Archaeological Project collection. I note the large amount of projectile points in this collection and compare it to projectile point counts from other large Fremont sites.I also note chronological patterns in Parowan Valley using projectile points as relative temporal markers. With this data and the data provided by other theses on Parowan Valley, I argue that sites in Parowan Valley served as centers for aggregation and other socio-economic practices in the Late Formative Period.

Hypersonic flight at sea-level conditions induces severe thermal loads not seen by any other type of current hypersonic system. Appropriate design of the hypersonic round requires a solid understanding of the thermal environment. Numerous codes were obtained and assessed for their applicability to the problem under study, and outside of the GASP Conjugate Heat Transfer module, Navier-Stokes code from Aerosoft, Inc., no efficient codes are available that can model the aerodynamic heating response for a fully detailed projectile, including all subassemblies, over an entire trajectory. Although the codes obtained were not applicable to a fully detailed thermal soak analyses they were useful in providing insight into ablation effects. These initial trade studies indicated that ablation of up to 1.25 inches could be expected for a Carbon-Carbon nosetip in this flight environment. In order to capture the thermal soak effects a new methodology (BMA) was required. This methodology couples the Sandia aerodynamic heating codes with a full thermal finite element model of the desired projectile, using the finite element code ANSYS from ANSYS, Inc. Since ablation can be treated elsewhere it was not included in the BMA methodology. Various trajectories of quadrant elevations of 0.5, 10, 30, 50, and 80 degrees were analyzed to determine thermal time histories and maximum operating temperatures. All of the trajectories have the same launch condition, Mach 8 sea-level, and therefore will undergo the same initial thermal spike in temperature at the nose-tip of approximately 3,100 K (5600R). Of the five trajectories analyzed the maximum internal temperatures experienced occurred for the 50 degree quadrant elevation trajectory. This trajectory experienced temperatures in excess of 1,000 K (1800R) for more than 80% of its flight time. The BMA methodology was validated by comparisons with experiment and computational fluid solutions with an uncertainty of 10% at a cost savings of over three orders of magnitude. / Ph. D.

Ce projet combine l’archéologie expérimentale, l’analyse morphométrique et la comparaison des résultats à l’assemblage archéologique de l’Abri Cellier (Dordogne, France) (N = 12) dans le but de quantifier l’apport du réaffûtage à la variabilité des formes et des dimensions des pointes de projectile aurignaciennes en bois de cervidé. La relecture morphofonctionnelle de la série expérimentale de Knecht (N = 79) couplée à une reproduction expérimentale récente (N = 9) démontre que la nature des dommages infligés au fût des pointes dépend (1) de la force du tir, (2) de la nature de la cible impactée et, (3) des propriétés biomécaniques du matériau employé. Pour sa part, le réaffûtage dépend (1) de l’expérience du réaffûteur et, (2) de la séquence technique employée. Ce comportement est standardisé et demeure indépendant du type de pointe de même que du type de dommage du fût. Les changements morphométriques associés à ce comportement se résument (1) à un déplacement progressif de l’épaule de la base vers le fût de la pointe, (2) à une tendance à l’accroissement de l’angle du fût et, (3) à une localisation des traces de réaffûtage sur le tiers distal de la partie distale de la pointe. Puisque l’utilisation et le réaffûtage sont deux processus impossible à départager sur les artefacts, nous proposons l’adoption d’une mesure, le ratio proximo-distal (RP/D) afin de traduire l’intensité de ces processus convergents et faciliter la comparaison entre les assemblages archéologiques. / This project combines experimental archaeology and morphometric analysis with a comparison with the archaeological assemblage from Abri Cellier (Dordogne, France) (N = 12) to quantify the contribution of resharpening to morphometric variability of Aurignacian projectile points made of antler. A morpho-functional re-analysis was performed on the experimental series produced by Knecht (N = 79), and combined with a recent experiment (N = 9) which showed that tip damage depends on (1) the projectile velocity, (2) the nature of the impacted target and, (3) the raw material’s biomechanical properties. On the other hand, resharpening depends on (1) the curator’s experience and, (2) the employed technical sequence. Also, resharpening is considered a standardized behaviour that remains independent of the point or tip damage type. Morphometric changes incurred by this behaviour can be summarized by (1) a gradual shift of the point’s shoulder from the base to the tip of the point, (2) a tendency of the tip to become more obtuse, and (3) a concentration of the curation stigmata at the distal third of the tip. Since use and resharpening are two processes that can’t be distinguished metrically on archaeological specimens, we propose a new metric the Proximo-Distal Ratio (RP/D), which translates the intensity of these two converging processes and allows inter-assemblage comparison.

Title of thesis: Ballistic cavity origin characterisation; auxiliary materials of a standardised or a special military ammunition. Aim of thesis: The goal of this work is to provide a regularising framework suggesting structural changes of the auxiliary materials in the impact zone of the various ammunition. Methods: A ballistic experiment based upon the piercing test of various ammunition types. For these tests different barrier materials were used (e.g. glycerine, soap, ballistic gel). A comparative study of the various physical aspects of the cavities was exercised. Several diagnostic methods such as dimensions verification, water volume measurement, projectile speed radar check, computer tomography or the high speed camera were used to determine the secondary cavity specifics. Results: This thesis identified several key parameters determining projectile behaviour in the auxiliary materials. The major determinants were: speed, position or homogeneity of the projectile on the impact. However the major parameter defining the "injury level" was the concluded that the highest Injury level has the prohibited "fragmentation effect ammunition". On the other hand it was pointed out that so called "Black Mamba" projectiles have lower injury effect, although manufactore claims otherwise. Key words:...

Lithic projectile armatures represent a significant innovation over thrusted spears in the subsistence strategies of hominins. Previous researchers have disagreed over the timing of the appearance of projectile weapons in the archaeological record (Brooks 2006; Shea 2006). To discover when projectile technology first appears in the Levant, I have compared tip cross-sectional areas, weights, and tip penetrating angles (three variables useful for discriminating between projectile and thrusting weapons) of pointed Blades, Levallois points, and Mousterian points with analogs from known and suspected chipped stone projectile points. Results indicate that pointed Blades from Tabun and Skhul caves are statistically indistinguishable from other suspected projectile point types. Levallois and Mousterian points from Tabun and Skhul are also statistically indistinguishable from suspected projectile types when the lower halves of the populations are compared. Consequently, I conclude that points from Tabun and Skhul caves fall within the known and suspected range of variation of projectile point morphology. / by David E. Leslie. / Thesis (M.A.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.