Made available in DSpace on 2014-06-11T19:34:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2004Bitstream added on 2014-06-13T19:47:49Z : No. of bitstreams: 1 padilha_rq_dr_guara.pdf: 4651598 bytes, checksum: 77a7edcf3c2fe16e30e62ec60549c1f8 (MD5) / Universidade Estadual Paulista (UNESP) / Este estudo objetiva analisar a influência da espessura de uma camada intermediária de níquel químico sob cromo duro eletrodepositado no aço de alta resistência, ABNT 4340 (utilizado em trens de pouso de aeronaves), com dureza de 39 HRc e 52 HRc. A análise é realizada por meio de dados obtidos nos ensaios de fadiga por flexão rotativa, das amostras revestidas com cromo duro, com e sem camada intermediária de níquel químico. As espessuras com melhor desempenho foram submetidas a ensaio de fadiga axial, em corpos de prova com e sem entalhe. Os resultados demonstram que a aplicação da camada de níquel químico é benéfica, em todas as espessuras analisadas, porém, há espessura que seu desempenho é ainda melhor. O tema proposto surgiu do interesse da ELEB - Embraer Liebherr Equipamentos do Brasil, em buscar por novas alternativas ou melhorias ao atual revestimento de cromo duro convencional. / The aim of this study is to analyze the effect of the thickness of an intermediate layer of chemical nickel under chromium electroplating on a high resistance steel ABNT 4340 (used in aircrafts landing gears), with hardness of 39 and 52 HRc. The analysis is done through data obtained from rotating bending fatigue tests of samples coated with hard chromium, with and without intermediate layer of chemical nickel. The thickness with better performance are submitted to axial fatigue tests, with and without notch. The results demonstrate that the application of a layer of chemical nickel is beneficial, in all of the analyzed thickness although some thicknesses present even better performance. The proposed work is due to the interest of the Brazilian Company of Aeronautics, Division of Equipments - EMBRAER/ELEB - in searching for new alternatives or improvements to the current coating with conventional hard chromium.

The balance of improving hard red spring wheat (Triticum aestivum L. emend Thell) yield while maintaining grain protein concentration continues to be a challenge in agriculture. The objective of the field research was to evaluate N fertilizer types, additives, rates, and application timing to find N management strategies that improved the efficiency of the applied N with regards to both grain protein and yield. Another aspect of this study was to determine if ground-based active sensor data can predict grain yield and/or protein content. Fertilizer treatments consisted of 2 application timings, 3 sources of N, 3 rates of N, and 2 additive types. Spring applications improved grain protein and yield compared to fall applications. Polymer coated urea shows promise in improving grain protein over urea alone. However, profitability is dependent on environmental factors that may influence N availability, as well as prices at the time that the grain is marketed. / Minnesota Wheat and Promotion Council

Malware detection is typically performed using either software scanners running inside the operating system or external devices designed to validate the integrity of the kernel. This thesis proposes a hypervisor-based malware that compromises the system by targeting the hard disk drive and leaving the kernel unmodified. The hypervisor is able to issue read and write commands to the disk while actively hiding these actions from the operating system and any detection software therein. Additionally, the hypervisor’s presence has minimal impact on the performance of the system. The ability to perform these commands compromises the confidentiality, integrity, and availability of the stored data. As a result, this thesis has widespread implications affecting personal, corporate, and government users alike.

This study tests an aspect of the environmental theory of Peter Huber outlined in his book <i>Hard Green: Saving the Environment from the Environmentalists: A Conservative Manifesto</i> (1999). Huber's thesis is that wealth leads to environmental conservation in two ways: 1) that wealthy nations develop and implement technologies to maximize the efficiency of land use, and 2) that wealthy individuals pour their wealth into the conservation of nature. Using secondary data analysis, I test the first national-level hypothesis with regressions of the variables "Gross National Income" and "ecological footprint," and test the second individual-level hypothesis with logistic regressions of the variables "income" and "donation to environmental groups," from both the General Social Survey and the World Values Survey. The results strongly refute Huber's national-level theory, with evidence that wealthy nations are actually less efficient at using land, but on an individual level the evidence suggests that the wealthy are indeed more likely to donate money to environmental groups. / Master of Science

This research aims to build upon existing literature and explore the experiences of d/Deaf and HoH people who grew up in Southern Ontario and were raised outside of the d/Deaf and Hard of Hearing community, and/or without access to sign language. / Throughout the literature, there is existing research on the experiences of people in the Deaf community from a culturally Deaf perspective and from a medicalized perspective of the condition of hearing loss; however, there is very literature on the experiences of people who do not fall within either of these binary views of what being d/Deaf and HoH is. This research aims to build upon existing literature and explore the experiences of d/Deaf and HoH people who grew up in Southern Ontario and were raised outside of the d/Deaf and Hard of Hearing community, and/or without access to signed language. This research is theoretically underpinned by critical disability theory and deaf critical theory—otherwise known as deaf crit—to broadly understand the nuances of how d/Deaf and HoH people are impacted by structural, systemic, and interpersonal experiences of audism, power, and oppression. This study relied on Photovoice as the research methodology to best center the perspectives of the participants through visual and textual analysis. Three participants participated in four virtual Photovoice workshops where they shared photographs in response to different prompts about their experiences as d/Deaf and HoH people. The ensuing discussion found the key themes: 1) the ability to explore their self-identity as d/Deaf and HoH people; 2) the importance of developing pathways to community early on in life; 3) the need for multiple supports when receiving care. This research contributes to the literature that centers the nuanced perspectives of those who are d/Deaf and HoH but raised without access to Deaf culture, community, and/or sign language and makes suggestions for future practice and policy that centers diverse needs and desires for support. / Thesis / Master of Social Work (MSW)

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The study of factors governing cutting tool performance and life is driven by manufacturers’ need to increase economic efficiency in their production facilities. Tooling and process optimization represent an ongoing opportunity for realizing substantial improvements, thus manufacturers continue to focus on promoting design and development of cutting tools and surface treatment technology relevant to machining. The central goal of cutting tool technology is to increase productivity while simultaneously reducing cost and meeting the quality targets of the machined parts. This thesis considers a nano-tribological approach to explain some of the past performance improvements in cutting tools used in dry machining applications and to look for opportunities to make further improvements in this field. The approach considers tribofilms, which are often described as tribo-oxides composed of either the base cutting tool material or freshly cut workpiece material transferred to the tool that have formed on the friction surface through interaction with the environment (air or cutting fluids) and a tribo-oxidation process. In general, the formation of tribofilms plays an important role in friction and wear behaviour by offering thermal protection and/or in-situ lubrication, which is especially important during dry machining of hard workpiece materials. The formation of various tribofilms on cutting tools have been reported through: 1) cutting tools with surface modification and further tribo-oxidation during the cutting process; 2) mass transfer from freshly cut workpiece material due to tool/chip contact in machining; and 3) interaction between the cutting tool surface and the cutting environment. This dissertation presents a novel method to control the formation of tribofilms on the cutting tool surface during machining of hard materials such as Inconel DA 718 and hardened steels (AISI T1 and AISI D2), with coated and uncoated tools. In particular, the frictional conditions experienced by the cutting tool during the initial period of cutting (the running-in stage) are shown to strongly influence whether or not beneficial processes related to adaptability will trigger. Employing a more aggressive cutting speed during the running-in stage noticeably enhances the generation of protective/lubricious tribo-ceramic films on the friction surface. When the cutting speed is subsequently reduced, the accelerated formation of beneficial tribofilms previously initiated is not fully removed and therefore the rate of tool wear is considerably less than if the tool is run at the lower cutting speed for its entire life. In addition, preliminary results are presented regarding tribofilms formation under the influence of the cutting environment, specifically the nature of the cooling medium used, which demonstrates an entirely different avenue to explore in terms of fine-tuning of tribofilms generation. The overall objective of this dissertation is to highlight different approaches to control the tribofilms formed on the cutting tool surface in order to benefit the machining process and to improve cutting tool life, material remove rate and the machined surface quality. Additionally, little work has been found demonstrating the formation of tribofilms on the tool surface through mass transfer from the workpiece material or through interaction with the cooling medium. Thus a secondary objective of this work is to demonstrate the formation of tribofilms through these different means and to investigate the effect of cutting parameters on their formation. / Thesis / Doctor of Philosophy (PhD)

A hard chromium electroplating process is normally used for preventing mechanical and electrical parts such as roller, piston and mold from the harmful environments and giving the good physical properties on the surface such as increased wear resistance, increased hardness, low frictional coefficient as well as good aesthetic look on the surface of workpieces. The problem that often found in this process is the deflected workpieces after plating process due to the low plating performance during a plating period. These deflected workpieces are needed to replating it again. However, the replating method causes a large amount of resource consumptions and increases the production time. To handle this problem, the plating solution temperature is needed to maintain the plating solution temperature at a set point about 50 °C in order to improve the plating performance during the plating period and decrease the occurrence of the deflected workpieces. In this work, the mathematical models are developed to explain the dynamic behavior of the plating solution temperature during the plating time and validated with the real data from a plant. The conventional (PID) controller is applied to this process for the purpose of keeping the plating solution temperature at the set point throughout the plating time. The result demonstrates that the developed mathematical models can be used to explain the dynamic behavior of the plating solution temperature because it gives the good simulation of the plating solution temperature with a slightly different from the real data. Furthermore, the PID controller shows the high control performance for maintaining the plating solution temperature at the set point throughout the plating period with small overshoot at the beginning of every batch.