An investigation of the cratering-induced motions occurring during the formation of bowl-shaped craters

The effects of the dynamic processes which occur during crater formation were examined using small hemispherical high-explosive charges detonated in a tank which had one wall constructed of a thick piece of clear plexiglas. Crater formation and the motions of numerous tracer particles installed in the cratering medium at the medium-wall interface were viewed through the wall of this quarter-space tank and recorded with high-speed cameras. Subsequent study and analysis of particle motions and events recorded on the film provide data needed to develop a time-sequence description of the formation of a bowl-shaped crater. Tables show the dimensions of craters produced in a quarter-space tank compared with dimensions of craters produced in normal half-space tanks. Crater growth rate summaries are also tabulated

Hall station and camera system operation and maintenance manual

The major components of the Hall station and camera system are described. The Hall film record of an event provides the time of flight of the projectile between the slits. A time mark generator is used to supply extremely short pulses of light at a known frequency. These pulses of light are used to produce timing marks on the edge of the film. Comparison of these marks with the spacing of the projectile images provides the information necessary to determine the time of flight of the projectile. Since the slits are installed with a known separation distance, calculation of the velocity of any object passing both slits is a simple matter

Performance of Whipple Shields at Impact Velocities above 9 km/s

Whipple shields were first proposed as a means of protecting spacecraft from the impact of micrometeoroids in 1947 [1] and are currently in use as micrometeoroid and orbital debris shields on modern spacecraft. In the intervening years, the function of the thin bumper used to shatter or melt threatening particles has been augmented and enhanced by the use of various types and configurations of intermediate layers of various materials. All shield designs serve to minimize the threat of a spall failure or perforation of the main wall of the spacecraft as a result of the impact of the fragments. With increasing use of Whipple shields, various ballistic limit equations (BLEs) for guiding the design and estimating the performance of shield systems have been developed. Perhaps the best known and most used are the "new" modified Cour-Palais (Christiansen) equations [2]. These equations address the three phases of impact: (1) ballistic (7 km/s), where the projectile melts or vaporizes at impact. The performance of Whipple shields and the adequacy of the BLEs have been examined for the first two phases using the results of impact tests obtained from two-stage, light-gas gun test firings. Shield performance and the adequacy of the BLEs has not been evaluated in the melt/vaporization phase until now because of the limitations of launchers used to accelerate projectiles with controlled properties to velocities above 7.5 km/s. A three-stage, light-gas gun, developed at the University of Dayton Research Institute (UDRI) [3], is capable of launching small, aluminum spheres to velocities above 9 km/s. This launcher was used to evaluate the ballistic performance of two Whipple shield systems, various thermal protection system materials, and other spacecraft-related materials to the impact of 1.6-mm- to 2.6-mm-diameter, 2017-T4 aluminum spheres at impact velocities ranging from 8.91 km/s to 9.28 km/s. Test results, details of the shield systems, and nominal ballistic limits for the two Whipple shields are shown in Figures 1 and 2

Using Phonics to Increase Reading Comprehension in English Language Learners

Abstract This paper discusses the implications phonics has on reading comprehension in the older English Language Learner. The subjects for this study were in the same Language Arts class in the Sheltered-Instruction Observation Protocol classroom, and they ranged from 15-20 years old. They were all in the same class because they were all Level III or IV with their language proficiency based on the WIDA ACCESS score in Speaking, Listening, Reading, and Writing. The study used Lexile scores from the Reading Inventory test used in the READ 180 classroom as the summative assessment of reading comprehension abilities. The focus for data was on pronunciation, fluency, and reading Lexile scores. In order to gather this information, they were received lessons based on phonics using the articles in READ 180, read those as fluency passages, and their common mispronunciations were assessed for whether it impeded comprehension. The conclusion of this study found that there was a decrease in comprehension with the group that focused on phonics and an increase with the vocabulary focus group. Keywords: phonics, secondary ELL, EL, reading comprehension, Lexil

Rethinking Collective Story: Olga Tokarczuk’s Tender Narrator and Spatiotemporal Entanglement

This article introduces characterisation of the tender narrator concept by Polish writer Olga Tokarczuk, which was a central point in her Nobel Prize lecture (2019). During the identification, three key elements of Tokarczuk’s project are specified: the bond of diegetic forms with climate and environmental crisis of the Anthropocene; dynamically changing, fragmented collective and individual perspectives; and the titular narrative tenderness manifested in sensitivity to more-than-human voices, networks, and relations. Through this, the potential of this idea is included in the repertoire of econarratological research and, more broadly, non-anthropocentric narrative theories. To detail the manifestations of the fourth-person narrative, as the tender narrative is also called, this paper problematises spatiotemporal experiences based on the example of Tokarczuk’s novel The Empusium (2024). In the analysis of how representations of time and space are mediated in the tender story, aspects such as interdependencies, despatialisation and fragmentation are brought to the fore

Structural Damage Prediction and Analysis for Hypervelocity Impact: Properties of Largest Fragment Produced by Hypervelocity Impact of Aluminum Spheres with Thin Aluminum Sheets

Results of a series of hypervelocity impact tests are presented. In these tests, 1.275-g, 9.53-mm-diameter, 2017-T4 aluminum spheres were fired at normal incidence at eight thicknesses of 6061-T6 aluminum sheet. Bumper thickness to projectile diameter (t/D) ratio ranged from 0.026 to 0.424. Nominal impact velocity was 6.7 km/s. Results of five tests using 6.35, 9.53, and 12.70-mm-diameter aluminum spheres and other aluminum alloy bumpers are also given. A large chunky fragment of projectile was observed at the center of the debris clouds produced by the impacts. The equivalent diameter of this large fragment ranged from 5.5 mm for the lowest t/D ratio to a minimum of 0.6 mm for the case where maximum breakup of the projectile occurred (t/D approximately 0.2 to 0.3). When the t/D ratio was 0.42, numerous large flaky fragments were evenly distributed in the external bubble of bumper debris. Velocity of the large central fragments decreased continuously with increasing t/D ratio, ranging from about 99 percent to less than 80 percent of the impact velocity. The change in the velocity of small fragments spalling from the rear of the projectile was used to obtain a relationship showing a linear increase in the size of the central projectile fragment with decrease in the shock-induced stress in the projectile

Hypervelocity Impact of Unstressed and Stressed Titanium in a Whipple Configuration in Support of the Orion Crew Exploration Vehicle Service Module Propellant Tanks

Hypervelocity impacts were performed on six unstressed and six stressed titanium coupons with aluminium shielding in order to assess the effects of the partial penetration damage on the post impact micromechanical properties of titanium and on the residual strength after impact. This work is performed in support of the definition of the penetration criteria of the propellant tanks surfaces for the service module of the crew exploration vehicle where such a criterion is based on testing and analyses rather than on historical precedence. The objective of this work is to assess the effects of applied biaxial stress on the damage dynamics and morphology. The crater statistics revealed minute differences between stressed and unstressed coupon damage. The post impact residual stress analyses showed that the titanium strength properties were generally unchanged for the unstressed coupons when compared with undamaged titanium. However, high localized strains were shown near the craters during the tensile tests

Beyond Anthropocentrism: Functions of the Second-Person Zoonarration in the Novel Rat by Andrzej Zaniewski

This paper presents a correlation between second-person narration and the more-than -human perspectivity in animal narratives. The analysis focuses on representations of “you” narration in Andrzej Zaniewski’s novel Rat, published for the first time in 1995. “Rat-centric” fiction, as Marco Caracciolo describes it, talks about various experiences of the title animal. Although the dominant diegetic form in the novel is the first-person narrative, the appearing parts of the text told from a second-person point of view turn out to be a significant element of a non-anthropocentric perspective. Considering the influence of form on the posthuman message, the paper is based on research in the field of animal studies and contemporary narratology, including, among others, Irene Kacandes’s “literary performative”, David Herman’s “double deixis” or Dominique Lestel’s “thinking with fur”. In this article, I propose to distinguish three functions of the second-person narrative in Rat: immersive, empathetic and identity roles. The immersive function participates in adapting a sensorimotor repertoire to the intersubjective perception of the non-human world. The second of them, the empathetic function, by bonding the human narratee with the animal character, opens a possibility of embodied co-experience and verification of anthropocentric norms. The third, identity function, participates in (de)constructing the rat selfhood. Findings of the proposed perspective of second-person zoonarration sheds new light on its formal opportunities for creating posthuman agency, thinking, and storytelling

A Translation Analysis: A Comparison of the English and Czech Versions of Guards! Guards! by Terry Pratchett

Obsah této bakalářské práce je zaměřen na analýzu překladu a překlad vybraných částí nacházejících se v novele Stráže! Stráže! od Terryho Pratchetta. V teoretické části je popsána překladová terminologie, teorie a přístupy společně s užitím příkladů převzatých z románu. V praktické části práce je provedena analýza překladu a subjektivní srovnání mezi vlastním a oficiálním překladem Jana Kantůrka.The content of this bachelor thesis is focused on the translation analysis and translation of selected parts occurring in novel Guards! Guards! by Terry Pratchett. In theoretical part translation terms, theory and approaches are described along with the usage of examples directly from the novel. In the practical part of the thesis the translation analysis and subjective comparison between official Jan Kantůrek's and mine translation is evaluated.Ústav moderních jazyků a literatu

Comportements antisociaux à l’adolescence : la supervision parentale comme facteur modérateur de l'influence des amis antisociaux

Les relations avec des amis déviants à l’adolescence peuvent être un terreau fertile pour le développement de comportements antisociaux. Au travers des processus de sélection et de socialisation, les amis s’influencent fortement, de manière telle que le niveau de comportements antisociaux des amis permet de prédire l’augmentation de comportements antisociaux chez les jeunes. La supervision parentale est susceptible de réduire l’influence négative des amis. Cette étude longitudinale vise à évaluer la contribution respective de l’influence des amis antisociaux et de différentes composantes de la supervision parentale (contrôle parental, sollicitation parentale et divulgation spontanée du jeune) sur le développement de comportements antisociaux au début de l’adolescence auprès d’un échantillon de 623 élèves âgés de 12 à 14 ans.   Il vise également à évaluer dans quelle mesure les différentes composantes de la supervision parentale interagissent avec l’influence des amis antisociaux afin de rendre compte du développement ultérieur des comportements antisociaux. Des analyses de régression hiérarchique indiquent que les comportements antisociaux des amis, ainsi que chacune des composantes liées à la supervision parentale, contribuent de manière unique et indépendante à prédire le développement ultérieur des comportements antisociaux. De plus, les adolescents qui rapportent un plus haut niveau de contrôle parental et qui ont davantage tendance à partager spontanément de l’information sur leur vie présentent moins de comportements antisociaux deux ans plus tard. Par contre, les jeunes qui rapportent un plus haut niveau de sollicitation parentale présentent plus de comportements antisociaux deux ans plus tard.   Les comportements parentaux (contrôle et sollicitation) ne viennent pas modérer l’influence négative des amis. Cependant, la propension du jeune à divulguer spontanément de l’information à ses parents modère l’influence négative des amis. En effet, chez les jeunes qui divulguent peu, les comportements antisociaux des amis ne permettent pas de prédire le développement des comportements antisociaux deux ans plus tard. Ces jeunes présentent un niveau de comportements antisociaux systématiquement plus élevé, et ce, indépendamment du niveau de comportements antisociaux des amis. Chez les jeunes plus enclins à se confier à leurs parents, les comportements antisociaux des amis sont alors positivement associés au développement ultérieur des comportements antisociaux.Friendships with delinquent peers during adolescence can foster the development of antisocial behaviour. Through the processes of selection and socialization, friends influence each other significantly, to the point that the friends’ level of antisocial behaviour can predict an increase in the adolescent’s antisocial behaviour. Parental supervision can reduce peers’ negative influence. This longitudinal study aims to examine the respective contributions of delinquent peers’ influence and three components of parental supervision (parental control, parental solicitation and child’s disclosure) on the development of antisocial behaviour at the beginning of adolescence among 623 students between 12 and 14 years old. It also aims to measure to what extent these components of parental supervision moderate the influence of antisocial peers in predicting the subsequent development of antisocial behaviour. The hierarchical regression analysis indicate that peers’ antisocial behaviour, as well as the components of parental supervision, contribute in a unique and independent way to predict the subsequent development of antisocial behaviour. Furthermore, adolescents who report a higher level of parental control, and who are more likely to freely disclose information to their parents, manifest less antisocial behaviour two years later. On the other hand, adolescents who report a higher level of parental solicitation manifest more antisocial behaviour two years later. Parental behaviour (control and solicitation) do not moderate the negative influence of peers, whereas adolescents’ tendency to disclose spontaneously information to their parents moderates the peers’ negative influence. Indeed, for adolescents reporting a lower level of disclosure, their peers’ antisocial behaviour cannot predict the development of their own antisocial behaviour two years later. These youths manifest a level of antisocial behaviour which is systematically higher, independently of their peers’ level of delinquency. For the adolescents who disclose more to their parents, peers’ antisocial behaviour are positively associated to the future development of their own antisocial behaviour