Maraging steels have got high strength and good toughness. Maraging steel MDN 250A grade is used for slat tracks on the leading edge of the wing of Light Combat Aircraft (LCA). This application requires high strength and good wear resistance. Required wear resistance for this application can be achieved by ion-nitriding (also called as Plasma nitriding or Glow discharge nitriding) process of case hardening. In conventional gas nitriding process the nitriding temperature is 500 – 550 0C, which is above the aging temperature of maraging steel. Ion-nitriding at temperatures lower than 480 0C is thought to be suitable for surface hardening for application of this material in slat tracks of the leading edge of the wing of LCA. Besides this ion-nitriding is stated to improve fatigue & wear resistance properties without significantly affecting other properties. Also this is a process where the thickness requirement is minimum for the wear properties accomplished. Further, no distortion, warpage and such other dimensional inhomogeneity problems are encountered. In ion-nitriding method glow discharge technology is used to introduce nascent (elemental) nitrogen to the surface of a metal part for subsequent diffusion into the material. The plasma assisted surface modification techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties. It has other advantages like nil or very thin white layer after nitriding and there is no machining or grinding involved for complex parts after the process. The hardened surface layers become an integral part of the basic material without any significant reduction in the properties of base material. Aim of the present work is to study ion-nitriding process on Maraging steels, to carry out ion nitriding of Maraging steel MDN 250A grade at different temperatures and evaluation of properties. Presently, the ion-nitrided slat tracks have been cleared for limited usage instead of full expected life. Studies are also needed to understand the fatigue behavior upon nitriding. The main aspects considered in this study are, optimization of thickness of the ion-nitrided layer and properties required for aircraft applications like slat tracks on the leading edge of the wing where wear resistance, corrosion resistance, mechanical properties like tensile strength, impact strength and fatigue strength are important. To establish the variation in the basic properties of maraging steel (MDN 250A Grade) because of ion nitriding. Aging of Maraging steel is done at 480 ± 5 0C with very close temperature control. In industrial ion-nitriding furnaces the temperature control is of the order of ± 10 0C. As a part of this research work ion-nitriding at three different temperatures which are well below 480 0C were chosen. These temperatures are 435 0C, 450 0C and 465 0C and soaking time i.e., ion-nitriding duration is 10 hours. Microstructure is characterized using optical microscope, scanning electron microscope and X-ray Diffraction. Properties evaluated include Hardness, Case depth, Tensile, Low Cycle Fatigue, Impact and Corrosion by Salt Spray. Optical microscopy and SEM examination don’t show change in core microstructure of the material after ion-nitriding. The iron compound formed in the hardened layer is Fe4N for all the three nitriding temperatures. Ion-nitrided specimens exhibit higher surface hardness and good case depth. Salt spray test results shows that there is animprovement in corrosion resistance after nitriding. The nitrided samples shown higher UTS and 0.2 % PS values than un nitrided ones, where as % Elongation and % Reduction in Area are lower for nitrided samples as compared to un nitrided samples. This can be attributed to the surface layer getting hardened because of ion nitriding. Impact strength of nitrided samples is lower compared to un nitrided samples. This is again due to the surface layer getting hardened because of ion nitriding. Low cycle fatigue properties obtained on ion-nitrided samples show improvement in the fatigue strength due to introduction of the residual compressive stresses. The mechanical properties satisfy the design requirements. Thus ion-nitriding of this Maraging steel (MDN 250A Grade) is suitable for parts which are subjected to constant wear and are complex in shape.

<p>A study of communication content, frequency and problems was performed at the Swedish Air Force Air Combat Simulation Centre, FLSC. The purpose was to investigate the connection between team communication and performance variables, to study communication problems during air combat and to employ and develop the PILOT method of communication problem analysis. Ten fighter pilots and four fighter controllers engaged in simulated air combat beyond visual range in teams on two sides, Blue and Red, with four pilots and one fighter controller each. Eight such training runs lasting 15 to 25 minutes were analyzed with regard to the Blue team’s communication during launch situations, i.e. one minute before launching a missile to either missile impact of failure, and problems during whole runs. The performance of the Blue team was rated by an experienced training instructor in six of the runs. It was hypothesized that positive outcomes would be associated with high communication frequencies but low communication problem rates. Results showed that high utterance frequencies were positively associated with positive global outcomes, i.e. wins, but not associated with high instructor ratings or launching hitting missiles. Incoherent results were found for communication problems. The results were discussed and further research suggested.</p>

<p>This thesis describes the evaluation of a prototype (Illustrator) for future simulator training of Within Visual Range - combat in the Swedish Air Force. The main focus was to collect and transform user acceptance data (expert opinions) to useful guidelines for continued development. Thirteen active fighter pilots participated in the study. The aim was to use expert opinion to study a) the psychological user acceptance, and b) the technical user acceptance, of the Illustrator together with c) gathering opinions for future improvement. Three psychological aspects were rated before and after the sessions to measure psychological user acceptance. For technical user acceptance, seven fidelity levels of the Illustrator were evaluated regarding realism, limitation of performance and importance of realism after the sessions. The sessions consisted of WVR-scenarios. Four different questionnaires were used for data collection. Two fidelity levels showed to diverge from the others in many ways, and were identified as major problems by the participants. No change of the psychological aspects was found between measurements. According to the results of the evaluation, suggestions and guidelines for future development are presented. Finally, issues of interest for future research are proposed.</p>

The introduction of harmful aquatic organisms and pathogens transferred through ships' ballast water and sediments from one coastal region to another has ecological, economic, environmental, and human impacts. The international community, through numerous binding and non-binding instruments, also sought to combat this problem. Ultimately, the International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004 was adopted by the International Maritime Organization as the dedicated legal regime intended to prevent, control and ultimately eradicate the introduction and spread of harmful aquatic organisms and pathogens through ships' ballast water and sediments. By its Regulations, the Convention sets out coastal/port and flag State obligations along with subsequently adopted technical Guidelines by which to implement it. Despite the importance of this problem, the Convention has not entered into force. This study assesses the potential of the Convention to promote achievement of the goal to prevent and eliminate this source of marine and biodiversity degradation and destruction. The study finds that the Convention constitutes a useful global legal regime within which steps can be taken to establish uniform ground rules, standards and practices to combat the introduction, transfer and spread of harmful aquatic organisms and pathogens across the world's coastal and marine areas. Nevertheless, its potential is undermined, among others, by the exemption of some categories of ships from its application, financial costs, especially to developing States, of implementing its requirements, and by the fact that its provisions do not account for other salient sources by which harmful aquatic organisms and pathogens are spread. Suggestions are made to encourage more ratification to bring the Convention into force and on remedying some of the weaknesses in the formulation of its rules. It is concluded that if it is ratified by sufficient and wide number of States as well as conscientiously implemented by States, adopting additional national laws and policies to regulate areas which are not addressed by the Convention, it would facilitate progress in the global effort to improve the protection of marine environments, ecosystems, and biodiversity, specifically, as regards the contribution towards combating the introduction and transfer of harmful aquatic organisms and pathogens via ships' ballast water and sediments. / The threat posed by harmful aquatic organisms and pathogens to the society at large is devastating. The Ballast Water Management Convention 2004 was adopted to remedy this problem. Though the Convention has potential to combat the threat, it has some ambiguities. This study concludes that if the provisions of the Convention, coupled with the recommendations made in this study are implemented at State level, we will have an international community that is free from the menace posed by harmful aquatic organisms and pathogens introduced through ships' ballast water and sediments, and a safer marine ecosystems will be ensued for us in due time.

The requirement to operate vehicles in low light and/or night environments whilst wearing night vision goggle (NVG) systems has become increasingly common during military operations. There is very limited research investigating injury risks associated with these systems during ground vehicle collisions. This study examined the injury risks associated with wearing the Australian Defence Force - Enhanced Combat Helmet (ECH) and NVG system, in frontal vehicle collisions. This project consisted of two components: (1) crash tests using a sled and (2) numerical simulations of impacts. Four dynamic sled tests were conducted using a 50th percentile, male, Hybrid III dummy positioned on a rigid seat. Frontal impact tests were performed at a 40 km/h change in velocity (*v) and 20 g deceleration. The test configurations were as follows: (a) Base; (no helmet or additional equipment); (b) ECH; and, (c) ECH and NVG. Condition (c) was carried out twice, to determine repeatability. The sled test protocols were reconstructed precisely with the numerical simulation package MADYMO and the simulations were shown to correlate well with the experimental results. Using this validated model, four parametric studies were undertaken to assess the influence of counterweights, seat cushion, seatbelt pre-tensioner, and the vehicle's *v and acceleration on injury risks. The study found that neck loads were within acceptable limits, with the exception of the neck extension moment, which was exceeded for all NVG conditions. Based on the parametric studies, no major improvements were observed in the neck extension moments with the use of counterweights or a seat cushion. In contrast the use of a seatbelt pre-tensioner was observed to decrease greatly this neck injury risk in certain scenarios. The study also identified that a *v of 15 km/h and peak acceleration of up to 14 g were required to keep the neck extension moment below the prescribed injury criteria. However, the high neck extension moment values may have been partially attributable to the stiff Hybrid III neck. This study identified a possible injury mechanism for soldiers using the ECH and NVG system during specific impact scenarios. The method applied in this project was designed to be repeatable.

Thesis (M.S.W.)--Smith College School for Social Work, Northampton, Mass., 2009. / Includes bibliographical references (p. 94-100).

No description available.

Thesis (MCom)--Stellenbosch University, 2015 / ENGLISH ABSTRACT : The continued and ever growing involvement of the South African National Defence Force (SANDF) to complex peacekeeping operations over the African continent has opened a platform in the academic field to better sharpen the SANDF’s performance and contribution to achieve peace in Africa. Previous deployments to various African countries has tested the SANDF’s level of preparedness. Although the organisation gives effort to train its forces to reach the desired level of combat readiness, the nature of the operations to which soldiers partake in has proven to be more demanding. This study was driven by the need to explore and provide a broader perspective of what constitute combat readiness. Utilising the SANDF, the study aimed to explore the relationship between the soldier’s relationship with the spouse (RWS) and the soldier’s relationship with the unit (RWU), and hardiness as a possible mediator variable to combat readiness (CR). Previous research and theories were explored to provide a theoretical background for the study variables. A non-experimental controlled inquiry was used to test the hypothesised relationship among the variables. A sample of 363 participants (across ranks, gender and race) was randomly selected from South African Infantry Battalion Group mobilising for a deployment to Sudan. Hypothesised relationships among the independent variables, mediator variable and dependent variable was determined using the correlational analysis (Spearman correlation). Partial Least Squares (PLS) – measurement and structural model was used to test the study model for combat readiness. The results showed significant correlations between the soldier’s RWS and CR. Furthermore, significant correlations were found between soldier’s RWU and CR. Partial mediation was explained by the path coefficients from RWU>hardiness>CR. No full mediating effect was found. The results also showed insignificant correlations between soldiers RWS and hardiness (rather than between soldier’s RWS and CR. These results were in support to previous research and proved to add insight to future research on CR. / AFRIKAANSE OPSOMMING : Geen opsomming beskikbaarbaar nie.

Uppsatsen är en fallstudie av landstriderna kring Narvik 1940 analyserade utifrån degrundläggande förmågorna med perspektivet att ta emot stöd.Trots tillskyndande stöd från allierade förband kunde inte de norska och allierade förbanden komma till ett avgörande mot de numerärt underlägsna och tillsynes avskurna tyska förbanden i fjällen kring Narvik. För att belysa de förutsättningar som rådde på taktisk nivå så används tre frågeställningar: -Hur fördelade sig de grundläggande förmågorna hos tyska förband respektive allierade förband under det studerade händelseförloppet? -Vilka förmågor var särskilt framträdande för de olika förbandens strid? -Vilka eventuella svårigheter att ta emot stöd i striderna kring Narvik är relevanta för svenska förhållanden? Resultatet av studien visar att avsevärda brister i förmågan till ledning hos de allierade förbanden förelåg varvid det tillskyndande stödet blev ineffektivt. Dessutom var de tyska förbandens goda förmåga till skydd samt uthållighet, viktiga faktorer för de allierades svårighet att komma till ett avgörande. / This study is a case study of the land war in the vicinity of Narvik 1940, analysed in perspective of the six basic capabilities of combat; effect on target, protection, mobility, command and control, sustainability and intelligence. The main angle is the challenges of receiving support. How come the Norwegians and supporting allied units weren’t able to defeat the outnumbered German troops in the mountains? To be able to filter out the essential factors on a tactical level the following questions are used: -How did the basic capabilities of combat appear among the allied and the German units? -Which capability was most decisive for the outcome of the battle between the opponents? -Which difficulties in receiving support are relevant for Swedish conditions? The result of the study reveals that severe mistakes in the command and control among the allied units caused ineffective support from the allied units. It also reveals that the protection and sustainability among the German units had an important role for the outcome.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-18T15:28:55Z No. of bitstreams: 1 ANDRÉ PAULO DE BARROS - TESE (PPGRN) 2015.pdf: 2498518 bytes, checksum: ae33b05349b74eb3129d3214742c78b0 (MD5) / Made available in DSpace on 2018-06-18T15:28:55Z (GMT). No. of bitstreams: 1 ANDRÉ PAULO DE BARROS - TESE (PPGRN) 2015.pdf: 2498518 bytes, checksum: ae33b05349b74eb3129d3214742c78b0 (MD5) Previous issue date: 2016-02-18 / O termo governança vem se tornando um conceito chave a ser entendido e aplicado dentro das práticas de gestão do meio ambiente, em especial nas políticas públicas ambientais. Através da governança, processos de gestão compartilhada são criados e a corresponsabilidade entre os usuários dos recursos naturais é estabelecida através da fixação de regras e de mecanismos voltados à resolução de conflitos. A qualidade da governança interfere diretamente na promoção do desenvolvimento sustentável não só em termos de resultados no sistema socioeconômico e ambiental, mas também na continuidade das políticas estabelecidas. De forma particular, este trabalho discute a governança e sua relação com a sustentabilidade institucional em torno da gestão dos recursos naturais. O pano de fundo para tratamento empírico dessa temática foram as ações de combate à desertificação partindo de uma perspectiva global (instituições e processos globais da UNCCD), passando pela análise nacional (ações no âmbito do governo federal), estadual (Estados que possuem núcleos de desertificação) até se chegar a um diagnóstico regional/local (Núcleo de Desertificação do Seridó/RN). Quatro questões específicas foram levantadas diante dessa problemática: Quais elementos são essenciais para garantir a sustentabilidade institucional das políticas de combate à desertificação no contexto nacional e internacional? Como analisar os elementos institucionais e de governança de uma política pública para inferir sobre sua situação de sustentabilidade institucional? No contexto brasileiro, quais problemas estão na base da não efetividade das políticas de combate à desertificação e quais caminhos devem ser trilhados com vista a sua solução? Objetivo geral da pesquisa foi analisar as relações entre governança e sustentabilidade das ações de combate à desertificação no contexto do Brasil apontando desafios e possíveis soluções para a baixa efetividade das políticas públicas que atuam sobre o tema. Para tanto, foram identificados os elementos institucionais e de governança essenciais para a sustentabilidade institucional de uma política pública; foi proposta, aplicada e validada uma metodologia de avaliação da governança e da sustentabilidade institucional das políticas de combate à desertificação nos âmbitos da UNCCD e do Brasil; e se discutiu os problemas que estão na base da não efetividade das políticas de combate à desertificação no contexto brasileiro apontando possíveis soluções. / The term governance has become a key concept to be understood and applied within the environmental management practices, especially in environmental public policy. Through governance, shared management processes are created and responsibility among users of natural resources is established by setting rules and mechanisms aimed at conflict resolution. Good governance directly affects the promotion of sustainable development not only in terms of results in the socioeconomic and environmental system, but also the continuity of the policies. In particular, this paper discusses the governance and its relation to the institutional sustainability around the management of natural resources. The backdrop for empirical this thematic treatment were to combat desertification actions starting from a global perspective (global institutions and processes of the UNCCD), through national analysis (actions within the federal government), state (States with core desertification) to arrive at a diagnosis regional / local (desertification Core Seridó / RN). Four specific issues were raised on this issue: What elements are essential to ensure institutional sustainability of combating desertification policies at the national and international context? How to analyze the institutional and governance of public policy elements to infer its institutional sustainability situation? In the Brazilian context, what problems are at the basis of non effectiveness of combating desertification policies and which paths must be trodden with a view to their solution? general objective of the research was to analyze the relationship between governance and sustainability of the actions combating desertification in the context of Brazil pointing challenges and possible solutions for the low effectiveness of public policies that act on the issue. Therefore, the institutional elements and essential governance for institutional sustainability of public policy were identified; It was proposed, implemented and validated a methodology for evaluating the governance and institutional sustainability of combating desertification policies in the areas of UNCCD and Brazil; and discussed the problems that underlie the non effectiveness of policies to combat desertification in the Brazilian context pointing out possible solutions