Thesis (M.S.)--University of Akron, Dept. of Civil Engineering, 2009. / "May, 2009." Title from electronic thesis title page (viewed 8/2/2009) Advisor, Ping Yi; Committee members, William H. Schneider IV, Anil Patnaik; Department Chair, Wieslaw K. Binienda; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 114-120). Also available via the Internet.

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Paul Griffin, Committee Member ; Hamid Garmestani, Committee Member ; Thomas Kurfess, Committee Member ; Steven Liang, Committee Member ; Shreyes Melkote, Committee Chair.

abstract: ABSTRACT This study explored the functions of dialogue in emerging adults' moral turning points. Through purposive sampling, the researcher interviewed 10 emerging adults between 25 and 30 years old about experiences of turning point conversations during the years of 18 and 25. This study employed constant comparative and grounded theory methodologies to analyze messages reported in memorable conversations during this period. Results indicated that dialogue functioned to educate, disturb, and maintain emerging adults' moral perception during this period of moral reorientation. Subcategories under each included dialogue that functioned to explain, invite, warn, direct or instruct, challenge, persuade, agitate, expose, inquire, legitimize, co-reflect, redefine, and affirm or reinforce. This report cites passages from interview data to highlight how dialogic themes informed or shaped changes in moral perception. In each participant's self-reported turning point conversations there was an admixture of dialogic functions at work. Notably, participants' experience of moral turning (degree and trajectory) varied despite there being similarity in intended functions of dialogue. / Dissertation/Thesis / IRB Approval Form / M.A. Communication Studies 2010

No description available.

Made available in DSpace on 2014-06-11T19:32:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-26Bitstream added on 2014-06-13T20:04:24Z : No. of bitstreams: 1 bahia_alh_dr_guara.pdf: 4900377 bytes, checksum: 181dbccfc8fe6a113dd46e2900635592 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com a constante evolução tecnológica nas áreas aeronáutica, espacial, automobilística, dentre outras, o uso de materiais com elevadas resistência mecânica e à corrosão em altas temperaturas tem sido cada vez mais necessário. Dentre os materiais que atendem a estes requisitos em temperaturas até 815 ºC está a liga à base de níquel Pyromet® 31V (N07032). Esta liga é utilizada na confecção de válvulas de exaustão em motores diesel de alta potência nas quais é exigida, além de resistência a altas temperaturas, uma grande resistência à sulfetação, à corrosão e à fluência. Entretanto, devido à sua grande resistência mecânica e baixa condutividade térmica, ocorre uma concentração de calor principalmente na interface cavaco-ferramenta dificultando assim a sua usinabilidade. Este trabalho teve como objetivo estudar a usinabilidade da liga Pyromet® 31V nas condições laminada à quente (42 HRC) e seguida de solubilização e envelhecimento (37 HRC) utilizando-se ferramentas de metal duro com e sem recobrimento, com lubrificação abundante e com a técnica de MQF. Em termos de vida da ferramenta, os melhores resultados para as ferramentas recobertas foram para avanços de 0,15 (laminadas) e 0,12 mm/rot. (solubilizadas). Devido à imprevisibilidade na formação do desgaste de entalhe e APC, não houve uma tendência clara de elevação ou queda na vida e/ou volume de material removido em função do avanço. Os mecanismos de desgaste atuantes nas ferramentas recobertas foram abrasão, attrition e martelamento e nas sem recobrimento foram difusão e abrasão. Na usinagem com MQF obteve-se bom acabamento superficial, vida razoável e reduzido volume de material removido. Já a ausência de recobrimento ocasionou uma redução de 70% no volume removido. Os cavacos gerados foram diversificados, mas predominantemente longos, destacando-se também a formação de cavacos duplos / Considering the constant technological developments in the aeronautical, space, automotive and nuclear areas, among others, the use of materials with high mechanical strength and corrosion resistance at high temperatures has been increasingly necessary. Among the materials that meet the mechanical strength and corrosion properties at temperatures up to 815 °C one can find the nickel base alloy Pyromet® 31V (N07032). This alloy is commonly applied in the manufacturing of high power diesel engines exhaust valves, where it is required besides the high temperature resistance, high resistance to sulfide-containing environments, corrosion and good resistance to creep. However, due to its high mechanical strength and low thermal conductivity, it occurs concentration of heat in the workpiece-tool and tool-chip interfaces, resulting in low machinability. This work aimed to study the machinability, using the cemented carbide coated and uncoated tools, of the hot-rolled (42 HRC) and solubilizing-aging (37 HRC) conditions of the Pyromet® 31V alloy, using two conditions, abundant fluid and MQF techniques. The best results for tool life with coated tools were with 0.15 (hotrolled) and 0.12 mm/rev. (solubilizing-aging) feed rates. Due to the unpredictability in the formation of the notch wear and built-up edge (BUE) it wasn’t observed a noticed tendency to increase or decrease in tool life and/or volume of removed material due to the feed rates. The wear mechanisms in coated tools were abrasion, attrition and hamming and in the uncoated tools were diffusion and abrasion. In the turning of this alloy with MQF, good surface finish, reasonable tool life and reduced volume of material removed were obtained. However, the absence of coated caused a 70% reduction in volume removed. The chips generated were of several types, but predominantly long, highlighting also the doubles chips formation

The main aim of this work was the machining by hard turning of surfaces with optical surface quality. A numerical target had been set as a surface roughness Ra = 10nm. It has been shown that achieving roughness of that magnitude by hard turning is possible. Individual work pieces exhibited the desired surface properties for short lengths at a time, but it proved to be very difficult to achieve these surfaces consistently and over longer cuts. The factors influencing the surface roughness were identified as tool defects and machine vibration in addition to the standard cutting parameters and choice of cutting tool. A model of surface generation in hard turning has been developed and good correlation between simulated and experimentally determined surface roughnesses was achieved. By introducing a material partition equation which determines the proportional contribution of material removal mechanisms in the undeformed chip a comprehensive method for assessing the contributing factors in material removal was developed. While it has been shown that surfaces in hard turning are almost exclusively generated by chip removal and plastic deformation the developed model is versatile enough to include elastic deformation of the work piece. With the help of the model of surface generation in hard turning it has been possible to attribute magnitudes of the influencing factors with respect to the cutting parameters such as feed rate and tool corner radius, and the main disturbances - tool defects and machine vibration. From this conclusions were drawn on the requirements for machine tools and cutting tools, which will need to be realised to make ultra-precision hard turning of surfaces of optical quality a feasible manufacturing process.

This thesis focuses on comparison of cermet cutting materials, which are used to manufacture reamer cutting edges. It contains review of current market reamer tools and suppliers of cermet semi-finished products. Cermet cutting tips were used to machine parts from carbon steel and analysis was made to compare wearing of the tools from different suppliers. This test was conducted on turning machine in working conditions typical for reaming. During this test there were taken notes on the wear of the tools and surface roughness of the part. The output of this is work is data processing, which indicates durability of each tested cermet.

The diploma thesis concerns CNC machining of rotary part. The first part briefly introduces options of multipurpose CNC machines and robotized workplaces. The main body of the thesis analyses two production departments; one of them operated by a robotic manipulator. The conclusion summarises the accomplished results of the thesis.

Task of this project is design of small vertical lathe. First part is focused on theory of turning technology, sort of lathe types, overview of vertical lathes including description of componets which vertical lathes consist of. At the second part of this project there is performed a propose of the machined part and a propose of cutting machine. The last part of this project provides base structure calculations and analysis needed for design proposal of a small vertical lathe according to specified parametres.