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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Modeling and Experimental Calibration of the Corrosion of Rha Steel in Immersion and Salt-Fog Environments

Jordan, Lydia Anna 10 August 2018 (has links)
An investigation into the general and pitting corrosion rates of rolled homogeneous armor (RHA) steel in immersion and saltog environments is presented. The mechanical properties of RHA steel have been studied, but the effects of corrosion on RHA have not been analyzed. An immersion environment of 3.5% NaCl was used to induce corrosion for the total testing period of 1500 hours for four immersion samples. A Qog cyclic corrosion tester was used to simulate a saltog/humidity/drying environment for four saltog samples. The different mechanisms of corrosion (general and pitting) and their associated rates were quantified through evolved hydrogen gas measurements, profilometry, Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). The primary corrosion mechanism in the immersion samples was general corrosion, while the primary corrosion mechanism in the saltog samples was pitting corrosion. The immersion samples showed no signs of pitting corrosion.
72

Principles, Functions, and Concepts for Compliant Mechanically Reactive Armor Elements

Andersen, Cameron S. 14 September 2007 (has links) (PDF)
There exists a great need for armor systems with greater mass efficiencies and ballistic limits. This thesis explores the development of a new field of armor capable of satisfying the increased demand for modern armor: Mechanically Reactive Armor or MRA. More specifically, the thesis focuses on Compliant MRA or CMRA. From the physics governing projectile-armor interactions, principles governing successful design of MRA are identified and presented. These principles or design approaches focus primarily on rejecting, minimizing, or absorbing the incoming projectile's kinetic energy. After identifying these principles, the specific mechanical functions required by the principles are isolated. These functions represent the physical behavior and capabilities of real mechanisms that satisfy the specific design principles. Using these mechanical functions and other benchmark concepts as a guide, established concept generation methodology is used to identify families of CMRA concepts that could supply the identified mechanical functions. These concept families are then narrowed by comparison of their respective ability to supply the required mechanical functions. The remaining concepts are selected for further study and simulation. In order to provide more detailed insight into the behavior of specific designs of these concepts, a quantitative model is developed. This simplified model is capable of predicting the behavior of the CMRA system when impacted by a ballistic projectile. After development, the model is then implemented to search the design space of the narrowed concepts. The search of the design space reveals important trends to be used in the design of CMRA elements. Finally, the feasibility of the specific designs is evaluated to judge their practicality in terms of practical materials and dimensions. It is shown that the concepts hold significant promise but require further design and development to provide the most desirable performance.
73

Heavy Metal in Medieval Europe

Klimmek, Sean M 21 March 2022 (has links)
How and why did plate armor come to be widely used in Medieval Europe? I trace the historical development of armor in Europe from antiquity to the middle ages, and then identify the main causes that pushed European warriors to develop and adopt plate armor from the 14th to the 16th centuries. I rely on prior research by scholars and historians of arms and armor, as well as primary source documents that describe arms and armor and their use in tournaments and on the battlefield. I conclude that a combination of social, political, military, and technical factors pushed European warriors to adopt plate armor. I also briefly discuss the demise of plate armor due to increasing use of firearms in the 16th century and the growth of professional armies.
74

Metallurgical Characterization of Armor Alloys for the Development and Optimization of Induction Bending Procedures

Kullman, Nicholas Allen 20 October 2011 (has links)
No description available.
75

Weldability Investigations of Advanced High Strength Steels Produced by Flash Processing

Hanhold, Brian J. 22 June 2012 (has links)
No description available.
76

The effects of posture, body armor, and other equipment on rifleman lethality

Kramlich, Gary R. 06 1900 (has links)
How does body armor and posture affect Soldier marksmanship? The Interceptor Body Armor (IBA) has significantly improved Soldier combat survivability, but in what ways does it change rifleman lethality? Moreover, can we model these effects so as to develop better tactics and operational plans? This study quantifies the effects of Soldier equipment on lethality through multi-factor logistic regression using data from range experiments with the 1st Brigade, 1st Infantry Division (Mechanized), at Fort Riley, Kansas. The designed experiment of this study estimates the probability of a qualified US rifleman hitting a human target. It uses the rifleman's equipment, posture, Military Occupational Specialty (MOS), and experience along with the target's distance, time exposure and silhouette presentation as input factors. The resulting family of mathematical models provides a Probability of Hit prediction tailored to a shooter-target scenario. The study shows that for targets closer than 150 meters, Soldiers shot better while wearing body armor than they did without. Body armor had a negative effect for targets farther than 200 meters, and this could significantly impact the employment of the Squad Designated Marksman. The study also shows that the kneeling posture is an effective technique and recommends standardized training on this method of firing.
77

A couraça como currículo-oculto: um estudo da relação entre rotina escolar e o funcionamento encouraçado / Armor as hidden-curriculum: a study on the relationship between school routine and the functioning of the armor

Garcia, José Gustavo Sampaio 06 August 2010 (has links)
Um estudo das relações existentes entre a estrutura de couraça e a prática escolar. Procura-se investigar o conceito de couraça e o fenômeno do encouraçamento como definido por Wilhelm Reich para aplicá-lo à realidade dos dias atuais, especialmente no ambiente escolar. Em um primeiro momento, realiza-se uma revisão da teoria reichiana do encouraçamento desde sua formulação no campo da psicanálise até sua aplicação ao funcionamento corporal e energético. Com base na visão estrutural do funcionamento encouraçado examina-se, então, o funcionamento virtual fronteiriço mais comum aos dias de hoje, relacionando-o às mudanças estruturais e superestruturais da atualidade. Acompanham-se, em seguida, as relações entre o aspecto biopsíquico dos indivíduos que compõem uma população e a forma cultural que a sociedade por eles formada assume. Na sequência, o estudo da rotina escolar enquanto currículo-oculto é empreendido em busca da compreensão do papel que esta tem na formação da couraça. Finalmente, uma confrontação é feita entre o funcionamento encouraçado e a forma com que a escola se organiza. Evidenciam-se aí as mútuas influências entre prática escolar e o encouraçamento. / A scrutiny on the relationship between school practice and the structure of the armor. The aim is to investigate the concept of the armor and the armoring phenomenon as defined by Wilhelm Reich to apply it to nowadays reality, especially in the school environment. At first, a review of Reich\'s theory of armoring was carried out, since its formulation in the field of psychoanalysis up to its application to body function and energy. Then, based on the structural view of the operation of the armor, the virtual borderline functioning, more common in the last decades, is examined and related to structural and super structural changes of present time. Following, the relationship between the bio-psychological aspect of individuals in a population and the cultural form that their society assumes is examined. Further, the study of school routine as hidden-curriculum is undertaken in search for the understanding of the role it plays in shaping the armor. Finally, a confrontation is made between the functioning of the armor and the way the school is structured. There becomes manifest the mutual influences between school practice and armoring.
78

Evaluation of Ballistic Materials For Back Protection Under Low Velocity Impact

Carboni, Marina 30 April 2004 (has links)
Low velocity impacts to the back are known to cause severe injury to crucial components such as the spine and kidneys. Researchers at Natick Soldier Center want to develop a solution that incorporates protection against low velocity impacts with the ballistic body armor (vest and plate) that is used today. The current ballistic body armor was developed to provide ballistic protection. Ballistic protection is designed to stop the penetration of bullets at velocities exceeding 300 m/s. Techniques to provide low velocity impact protection include reducing transmitted force by elongating collision time. In order to develop back protection for the soldier against low velocity impacts the performance of the ballistic body armor and impact protecting foams was evaluated. Low velocity impact tests were performed based on European standards for back protectors for horse riders (EN 13158) and motorcyclists (EN 1621-2). Performance requirements outlined by the standards and published literature established peak forces of 4 kN and 9 kN transmitted through materials under impact as minimum levels of safety before significant injury occurs. Experiments were conducted at an energy level of 4 J to compare the performance of different materials. Energy levels were then increased until maximum acceptable force transmissions were reached. At 4 J the ballistic materials showed peak transmitted forces between 11.0-16.2 kN. This indicated that the ballistic materials were not an adequate method to provide sufficient back protection. The addition of polyurethane foams to ballistic materials reduced peak force values by a factor of 15. Energy levels of 25 J and 40 J were reached with peak forces of 3.5 kN and 6.6 kN. This research provided a basis for the future development of protective equipment that provides both ballistic and low velocity impact protection.
79

Avaliação das armaduras de tração de riser flexível durante ensaios axiais de tração e fadiga

Bueno, Antonio Fernando Burkert January 2010 (has links)
O presente trabalho tem como objetivo avaliar as tensões atuantes no conjunto conector e duto flexível de camadas não aderentes durante ensaios com carregamentos axiais de tração e fadiga. Estes ensaios são utilizados para a qualificação de dutos flexíveis. Foram desenvolvidos e patenteados alguns modelos de conectores contemplando apenas a parte estrutural. Ensaios preliminares de tração e fadiga, com dois conectores diferentes e um segmento de riser de dimensões reduzidas, foram realizados visando a seleção do modelo de melhor desempenho em um pórtico. O conector de melhor desempenho foi então ensaiado em uma bancada com dimensões que atendessem ao documento da Petrobras a I-ET 3500.00.6500-291-PAZ-001 - Non standartized Prototype qualification tests of flexible pipes (2007). Tanto os ensaios do pórtico como o de bancada, foram monitorados com strain gages colados nos tendões da armadura externa de tração próximos aos conectores. O foco deste trabalho está nas armaduras de tração na interface com a resina do conector. Questões quanto ao desempenho da mesma em fadiga são de grande importância prática. Complementando a parte experimental, foram construídos modelos sólidos tridimensionais, baseados no Método dos Elementos Finitos para análise das tensões. A comparação dos resultados das diferentes metodologias validou o modelo numérico possibilitando melhor entendimento das variações de tensões nas armaduras de tração na interface com os conectores. Isso possibilitou responder a importantes questões quanto ao desempenho em fadiga bem como possíveis melhorias no projeto de conectores para dutos flexíveis. Existem trabalhos referentes à análise de tensões dos tendões nos conectores considerando o estado plano de tensões. O presente estudo dos tendões usando modelos tridimensionais, abordagem não encontrada em literatura aberta, avalia melhor a concentração de tensões nos tendões na entrada do conector. A motivação deste estudo se deve tanto à falta de informações detalhadas das tensões e deformações nos tendões na interface com o conector, como pela importância das mesmas, em componentes vitais à explotação de petróleo Offshore. / This aim of this work is to evaluate stresses which actuate on a system made up of a unbonded flexible pipe and a end fitting during static and dynamic axial loading mechanical tests. These tests are used as a means of qualification of flexible pipes. The structural design of models of end fittings were developed and patented. Preliminary static and dynamic tests with two different end fittings and a smalldimensioned riser segment were performed in a frame in view of selecting the bestperforming type. After this evaluation, the end fitting with the best performance was tested in a rig with dimensions according to Petrobras document I-ET 3500.00.6500-291-PAZ- 001 - Non standartized Prototype qualification tests of flexible pipes (2007). Tests performed in the frame and on the rig were monitored with resistance strain gages attached to wires of the external armor, on the interface with the end fitting resin, since performance of this region under fatigue is of utmost practical importance. Three-dimensional solid models were built using the Finite Element Modelling (FEM) method, as a way of validating experimental results. Comparison of results obtained from the different methodologies validated the numerical model, allowing a better understanding of the variations of stresses in the interface of the riser with the end fitting. This led to the solution of many doubts regarding fatigue performance as well as possible improvements in the design of flexible riser end fittings. Existing work published in literature considers only plane stress; the present study, based on 3D models which are not found in literature, is thought to better describe the stress concentration on the wires at the end fitting interface. The motivation of this work relies on the lack of detailed information of the stress and strain to which wires are subjected at the interface with the end fitting, as well as the importance of these in vital components for offshore oil exploration.
80

A couraça como currículo-oculto: um estudo da relação entre rotina escolar e o funcionamento encouraçado / Armor as hidden-curriculum: a study on the relationship between school routine and the functioning of the armor

José Gustavo Sampaio Garcia 06 August 2010 (has links)
Um estudo das relações existentes entre a estrutura de couraça e a prática escolar. Procura-se investigar o conceito de couraça e o fenômeno do encouraçamento como definido por Wilhelm Reich para aplicá-lo à realidade dos dias atuais, especialmente no ambiente escolar. Em um primeiro momento, realiza-se uma revisão da teoria reichiana do encouraçamento desde sua formulação no campo da psicanálise até sua aplicação ao funcionamento corporal e energético. Com base na visão estrutural do funcionamento encouraçado examina-se, então, o funcionamento virtual fronteiriço mais comum aos dias de hoje, relacionando-o às mudanças estruturais e superestruturais da atualidade. Acompanham-se, em seguida, as relações entre o aspecto biopsíquico dos indivíduos que compõem uma população e a forma cultural que a sociedade por eles formada assume. Na sequência, o estudo da rotina escolar enquanto currículo-oculto é empreendido em busca da compreensão do papel que esta tem na formação da couraça. Finalmente, uma confrontação é feita entre o funcionamento encouraçado e a forma com que a escola se organiza. Evidenciam-se aí as mútuas influências entre prática escolar e o encouraçamento. / A scrutiny on the relationship between school practice and the structure of the armor. The aim is to investigate the concept of the armor and the armoring phenomenon as defined by Wilhelm Reich to apply it to nowadays reality, especially in the school environment. At first, a review of Reich\'s theory of armoring was carried out, since its formulation in the field of psychoanalysis up to its application to body function and energy. Then, based on the structural view of the operation of the armor, the virtual borderline functioning, more common in the last decades, is examined and related to structural and super structural changes of present time. Following, the relationship between the bio-psychological aspect of individuals in a population and the cultural form that their society assumes is examined. Further, the study of school routine as hidden-curriculum is undertaken in search for the understanding of the role it plays in shaping the armor. Finally, a confrontation is made between the functioning of the armor and the way the school is structured. There becomes manifest the mutual influences between school practice and armoring.

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