Submitted by Izabel Monteiro (izabel_22@hotmail.com) on 2016-06-17T13:48:46Z No. of bitstreams: 1 Dissertação - Elielton LIma Costa.pdf: 1439249 bytes, checksum: 0d4b3b7c30523b7ea83786adbcd441bc (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-06-23T20:16:09Z (GMT) No. of bitstreams: 1 Dissertação - Elielton LIma Costa.pdf: 1439249 bytes, checksum: 0d4b3b7c30523b7ea83786adbcd441bc (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-06-23T20:21:23Z (GMT) No. of bitstreams: 1 Dissertação - Elielton LIma Costa.pdf: 1439249 bytes, checksum: 0d4b3b7c30523b7ea83786adbcd441bc (MD5) / Made available in DSpace on 2016-06-23T20:21:23Z (GMT). No. of bitstreams: 1 Dissertação - Elielton LIma Costa.pdf: 1439249 bytes, checksum: 0d4b3b7c30523b7ea83786adbcd441bc (MD5) Previous issue date: 2016-03-09 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / The aim of the study was to evaluate the extrusion of debris, apical transportation, centering ability and wear area further by Rotary and reciprocating instruments used in large root canals. Forty-five mandibular premolar with only single-rooted teeth and single canal and apical diameter largest that 300 μm. In order of the standardization the samples were fixed in acrylic resin and placed in styrofoam platform. Cone-beam computed tomography analysis was perfomed before and after instrumentation for apical third images acquisition for to appoint the anatomic and surgical diameter. The extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The mandibular premolar teeth were randomly assigned to four groups. The root canals were prepared according to the manufacturers’ instructions. Group 1 (Protaper Universal - PTU): All PTU instruments were used to the full length of the canals according to the manufacturer’s instructions using a gentle in-and-out motion. The instrumentation sequence was S1, S2, F1, F2, F3, F4 and F5. Group 2 (Protaper Next - PTN): All PTN instruments were used to the full length of the canals according to the manufacturer’s instructions using a gentle in-and-out motion. The instrumentation sequence was X1, X2, X3, X4 and X5. Group 3 (Reciproc R50 – R50): Reciproc file was used in a reciprocating, slow in-and-out pecking motion according to the manufacturer’s instructions. The flutes of the instrument were cleaned after 3 in-and-outmovements (pecks). In each sample, a total of 1-mL distilled water was used as the irrigant solution between files. Before weighing the dry debris, the tubes were stored in na incubator at 70 °C for 5 days to evaporate the distilled water. The quantitative evaluation of apically extrued debris was analyzed by weight difference before and after instrumentation. Apical transportation, centering ability and wear area were analyzed for images of the cone-beam computed tomography worked in the software OsiriX. The values were statistically analyzed (Kruskal-Wallis, the Dunn multiple comparisons test). The results showed that the group PTN produced significantly more debris compared with both groups (P<0.01). All groups had apical transportation values in the 2°, 3° e 4° mm apical, with no significant difference among them (P>0.05). No technique had perfect centering abitity (=1.0). the group R50 showed largest wear area, with significant difference (P<0.05) compared with both groups. In conclusion, under the condition of this study, the group PTN produced more debris compared with both groups. The R50 intrumentation showed largest wear area that both Group PTN and PTU, with significant difference. All technique showed no had perfect centering abitity and showed apical transportation, no with significant difference between them. / O objetivo do presente trabalho foi avaliar o extravasamento apical de debris, desvio apical, capacidade de centralização e área de desgaste promovidos por sistemas de instrumentação rotatórios e reciprocante indicados para canais amplos. Foram selecionados 45 pré-molares inferiores com único canal e raiz e diâmetro apical maior que 300 μm. Com intuito de padronização das amostras fixou-se os espécimes em base de resina acrílica e posicionou-os em plataforma de isopor. Os espécimes foram submetidos a tomografia computadorizada antes e após a instrumentação para determinação do diâmetro anatômico e cirúrgico a fim de favorecer as mensurações do estudo. Durante a instrumentação os dentes foram fixados em frascos de vidro para a pesagem dos debris apicais. Os dentes selecionados foram distribuídos em três grupos (n=15) e instrumentados de acordo com as indicações dos respectivos fabricantes dos sistemas. Grupo I (Protaper Universal - PTU): todos os instrumentos, S1, S2, F1, F2, F3, F4 e F5, foram inseridos no comprimento de trabalho real com avanço progressivo e movimentos de vai e vem no interior dos canais. Grupo II (Protaper Next - PTN): instrumentos X1, X2, X3, X4, X5 foram inseridos no comprimento de trabalho real com avanço progressivo e movimentos de vai e vem no interior dos canais. Grupo III (Reciproc – R50): Reciproc R50 foi inserido progressivamente no canal, inseria-se e removia-se o instrumentos e limpava-o com gaze. Esse procedimento foi repetido até o alcance do comprimento de trabalho, em três avanços. Utilizou-se 1 mL de água bidestilada como solução irrigante a cada troca de instrumento. Os frascos de vidro contendo debris foram armazenados em estufa a 70 °C por 5 dias até a secagem completa da água. Determinou-se a quantidade de debris pelo cálculo da diferença dos pesos iniciais e finais dos frascos. As imagens tomográficas foram manipuladas no programa OsiriX a fim de se determinar o desvio apical, capacidade de centralização e área de desgaste. Os dados foram submetidos ao teste não-paramétrico de Kruskal-Wallis e teste de Múltiplas Comparações de Dunn. Os resultados do extravasamento de debris mostraram que o grupo da PTN apresentou maior quantidade de extravasamento, com diferença estatisticamente significante (P<0.01) em relação aos outros grupos. Todas as técnicas apresentaram desvio apical nos 2°, 3° e 4° milímetros apicais, porém sem diferença estatística significante (P>0.05). Nenhuma técnica apresentou centralização perfeita (=1.0). O grupo da R50 apresentou maior área de desgaste, com diferença estatisticamente significante (P<0.05) em relação ao demais grupos. Com base na metodologia empregada e nos resultados obtidos, concluiu-se que o sistema PTN apresentou estatisticamente maior quantidade de extravasamento de debris quando comparado aos demais grupos. O grupo R50 apresentou maior área de desgaste que os grupos PTN e PTU com diferença estatística significativa. Todas as técnicas tiveram tendência a centralização e apresentaram desvio apical, porém sem diferenças estatísticas entre si.

Orientador: Antonio Carlos Bannwart / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-12T08:12:48Z (GMT). No. of bitstreams: 1 Karcher_Viviane_M.pdf: 1731022 bytes, checksum: 355de3e34591ff15d14ab367330328f8 (MD5) Previous issue date: 2008 / Resumo: Durante a produção de petróleo, é comum o aparecimento de água sob a forma de gotas finamente dispersas no óleo. A água pode ser oriunda de métodos de recuperação avançada e/ou do próprio reservatório (água conata). O cisalhamento turbulento produzido durante o escoamento destes fluidos através de dutos ou dispositivos, como bombas, ou até mesmo no reservatório, pode causar a formação de emulsões de água em óleo (A/O). Para os óleos pesados,estas emulsões permanecem estáveis por um período longo devido à presença de agentes emulsificantes naturais no petróleo cru. Por essa razão, a separação dessas emulsões necessita de equipamentos específicos, o que contribui para o aumento do custo do processo. O objetivo deste estudo é investigar as propriedades interfaciais de emulsões A/O compostas por água e petróleo pesado brasileiro. Para tanto, um aparato experimental foi construído com o objetivo de calcular a energia interfacial dessas emulsões. As emulsões A/O foram geradas através de um aparelho homogeneizador rotativo imerso em um vaso calorimétrico. Dois métodos foram empregados: o método calorimétrico, baseado no balanço de energia da emulsificação, e o método padrão, baseado na medida do tamanho e distribuição das gotas através da técnica de microscopia óptica. As incertezas nas medidas experimentais, em ambos os métodos, foram estudadas a fim de avaliar a viabilidade de cada um. Como principais resultados deste estudo, as magnitudes relativas dos termos do balanço de energia durante a emulsificação foram obtidas. O comportamento reológico destas emulsões também foi estudado. / Abstract: In petroleum production operations, water is commonly present within the oil phase as a finely dispersed phase. This situation originates from enhanced oil recovery methods and/or the presence of connate water inside the own reservoir. The turbulent shear associated with fluid flow during of heavy crude transportation through pipelines may cause the formation of water-in-oil emulsions (W/O). These remain stable for a long time, due the presence of naturally emulsifying agents in the crude oil phase. Therefore, emulsion separation requires specific equipments which contribute to increase the processes costs. The main purpose of this study is to investigate the interfacial properties of W/O emulsions composed by water and a Brazilian heavy crude oil. For that purpose an experimental set-up was built in order to measure the interfacial energy of the emulsions. The W/O emulsions were prepared in a calorimeter vessel by using a rotating impeller. Two methods were used, namely, the calorimetric method based on the energy balance for the emulsification and the standard method of the droplet size and distribution by means of a digital microscope. The uncertainty in experimental measurements was determined for both methods, in order to evaluate their feasibility. The main result of this research is the determination of the relative magnitudes of the different terms in the energy balance during emulsification. Results for the rheological behavior of W/O emulsions are also reported. / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

Two-phase flow in small tubes and channels is becoming a common phenomenon in industrial processes. However, the study of two-phase flow regimes in small tubes is still at its infancy. The previous studies are reviewed and discussed in the literature section. The problems and inconsistencies encountered in the earlier studies are presented and discussed. The experimental facility is introduced in the chapters that follow. They include a section on the design of the experimental system and the test sections, the selection of the experimental parameters and the introduction of the purposely-developed programs to control the experiments and collect and process the data. The methodology of the calibration and the uncertainty analysis, the problems encountered and their solutions and the single-phase validation experiments are also described. In this project we studied the effect of tube diameter and fluid flow parameters on flow patterns in small tubes using R134a as the working fluid. The tested tube diameters were 1.10, 2.01, 2.88 and 4.26 mm; the fluid pressures were 6, 10 and 14 bar; the liquid and gas superficial velocities covered a range of 0.04-5.0 m/s and 0.01-10.0 m/s respectively. The observed flow patterns included bubbly, dispersed bubble, confined bubble, slug, chum, annular and mist flow. Twelve integrated flow maps are sketched in this report. The obtained results were compared with earlier experiments by other workers and with existing models, with obvious differences in the prediction of the transition boundaries. A set of new models and correlations were developed, based on the new data for boiling R134a presented in this thesis, to predict the effect of tube diameter and fluid properties on the transition boundaries. Some also agreed with the limited data available from earlier studies for adiabatic air-water flow in small to normal size tubes.

Moore&apos;s law states that the amount of computational power available at a given cost doubles every 18 months and indeed, for the past 20 years there has been a tremendous development in microprocessors. However, for the last few years, Moore&apos;s law has been subject for debate, since to manage heat issues, processor manufacturers have begun favoring multicore processors, which means parallel computation has become necessary to fully utilize the hardware. This also means that software has to be written with multiprocessing in mind to take full advantage of the hardware, and writing parallel software introduces a whole new set of problems. For the last couple of years, the demands on telecommunication systems have increased and to manage the increasing demands, multiprocessor servers have become a necessity. Applications must fully utilize the hardware and such an application is the Diameter Credit Control Application (DCCA). The DCCA uses the Diameter networking protocol and the DCCA&apos;s purpose is to provide a framework for real-time charging. This could, for instance, be to grant or deny a user&apos;s request of a specific network activity and to account for the eventual use of that network resource. This thesis investigates whether it is possible to develop a Diameter Credit Control Application that achieves linear scaling and the eventual pitfalls that exist when developing a scalable DCCA server. The assumption is based on the observation that the DCCA server&apos;s connections have little to nothing in common (i.e. little or no synchronization), and introducing more processors should therefore give linear scaling. To investigate whether a DCCA server&apos;s performance scales linearly, a prototype has been developed. Along with the development of the prototype, constant performance analysis was conducted to see what affected performance and server scalability in a multiprocessor DCCA environment. As the results show, quite a few factors besides synchronization and independent connections affected scalability of the DCCA prototype. The results show that the DCCA prototype did not always achieve linear scaling. However, even if it was not linear, certain design decisions gave considerable performance increase when more processors were introduced.

La présente thèse est constituée par un ensemble d'études expérimentales sur l'effet des hautes pressions sur les nanotubes de carbone mono-parois, individualisées, fermés ou ouvertes, donc vides ou remplis d'eau. Les techniques des hautes pressions et de la spectroscopie Raman ont été combinées afin d'étudier l'effondrement des nanotubes et de sonder les modifications induites par l'effet de la pression. Les coefficients de pression des modes radiaux de respiration (RBM) ont été obtenus avec identification individuelle par chiralité. Les RBM des nanotubes remplis d'eau ont pu être observés à des pressions bien plus élevées que pour des nanotubes vides. Après un cycle à haute pression, les nanotubes vides de diamètre plus important n'étaient pas détectables tandis que les tubes de diamètre sous-nanométrique se sont remplis d'eau. Ces observations suggèrent que les nanotubes de diamètre le plus faible ont une meilleur stabilité sous pression qui est accrue par le remplissage par de l'eau. Une réponse inusuelle du nanotube (7,2) suggère que la chiralité peut avoir aussi un rôle aussi important dans la stabilité structurelle, en tout cas pour les nanotubes de plus faibles diamètres. De son côté, l'évolution des modes de vibration tangentiels suggère l'effondrement radial des nanotubes vides d'un diamètre d'environ de 1.32 nm à une pression proche de 4 GPa, en accord avec les prévisions théoriques les plus récentes. Ces mêmes tubes remplis d'eau, présentent un effondrement à une pression qui se situe au-delà de 16 GPa / The present thesis constitutes a set of experimental studies on the effect of high pressures on single wall carbon nanotubes, individualized, closed or open, therefore empty or filled with water. High-pressure techniques and Raman spectroscopy were combined to study the radial collapse, as well to probe the pressure-induced modifications. Chirality-resolved pressure derivatives were obtained for the radial breathing modes (RBM). The RBM of water-filled could be observed at pressures higher than those of empty. After a high-pressure cycle, empty nanotubes of larger diameters were not detectable anymore, while sub nanometric diameter ones became filled with water. Such observations suggest that thinner nanotubes have better pressure-stability, which is increased upon water filling. An unusual response of the (7,2) nanotube suggests that the chirality may have also an important role on the structural stability for small diameters. The evolution of the tangential modes suggest the onset of radial collapse of empty nanotubes averaging 1.32 nm diameter at about 4 GPa, in agreement with the latest theoretical predictions. These same nanotubes, though water-filled, they collapse at pressures higher than 16 GPa

Polyvinylidene difluoride (PVDF) is a functional polymeric material that can be used for a wide variety of applications. There are many new future applications that were recently suggested for electrospun PVDF fibers. Electrospinning is a process capable of producing nano to micro sized PVDF fibers in a web. It is important to control the structure of the web during electrospinning because by controlling the structure of the web it is possible for the PVDF fiber web to have increased performance in comparison to other common forms of PVDF. While past scientific literature focused on applications of PVDF fibers, little was known on how to control structure of PVDF fiber webs during production. Even though defects can alter the structure and performance of the web only a few studies reported defect occurrence and how to reduce the occurrence of defects in fiber webs. This research investigated the defect free production space of electrospun PVDF and provided streamlined guidelines for manufacturers to use for electrospinning PVDF webs. Many studies looked at influencing fiber diameter and beading with one factor at a time experimentation; this work was foundational and was able to identify many important electrospinning parameters. But this methodology neglected the possibility of parameter interactions and often did not look at the effects of parameters on the occurrence of defects and the structure of those defects. Therefore a systematic understanding that included all of the important electrospinning parameters in relation to fiber and defect structure was needed to present a clear picture of the possibilities for controlling the structure of electrospun PVDF webs. This research explored ways to control the structure of PVDF fiber webs. The production space and control of web structure was explored by using a regression analysis to identify important parameters and interactions. Then the regression analysis was used to determine the effects of the important parameters that influenced the web structure. This research showed that the web structure can be controlled using solution parameters and processing parameters and monitored by system parameters. In addition, this study showed that by controlling the web structure it was possible to influence the porosity and piezoelectric properties of PVDF fiber webs. In its entirety, this research presents a systematic approach to producing PVDF fibers for tailored web performance.

Class of 2015 Abstract / Objectives: To evaluate the in vitro performance of various pressurized metered dose inhaler (pMDI) formulations by cascade impaction primarily focusing on throat deposition, fine particle fraction (FPF), and mass-median aerodynamic diameter (MMADR) measurements Methods: Ten solution pMDIs were prepared with varying cosolvent species in either low (8% w/w) or high (20% w/w) concentration. The chosen cosolvents were either alcohol (ethanol, n-propanol) or acetate (methyl-, ethyl-, and butyl acetate) in chemical nature. All formulations used HFA-134a propellant and 0.3% drug. The pMDIs were tested by cascade impaction with three different inlets to determine the aerodynamic particle size distribution (APSD), throat deposition, and FPF of each formulation. Theoretical droplet evaporation time (DET), a measure of volatility, for each formulation was calculated using the MMADR. Results: Highly volatile formulations with short DET showed consistently lower throat deposition and higher FPF than their lower volatility counterparts when using volume-constrained inlets. However, FPF values were not significantly different for pMDI testing with a non-constrained inlet. The MMADR values generated with volume-constrained inlets did not show any discernible trends, but MMADR values from the non-constrained inlet correlated with DET. Conclusions: Formulations with shorter DET exhibit lower throat deposition and higher FPF, indicating potentially better inhalational performance over formulations with longer DET. There appear to be predictable trends relating both throat deposition and FPF to DET. The shift in MMADR values for volume-constrained inlets suggests that large diameter drug particles are preferentially collected in these inlets.

This study focuses on certain urban forestry aspects of the City of Tshwane (previously Pretoria) and in particular that of growth rate and carbon sequestration estimates of street trees with the aim of quantification of the value of these trees. The relationships between tree height and crown dimensions to stem diameter and tree age, as well as the relationship between stem diameter to tree age enable the development of growth rate equations that predict tree dimensions and carbon storage. This permits the calculation of monetary values of urban trees and thus the modelling of costs and benefits of urban forests. The main objectives were (1) to develop tree height, crown diameter, crown height, and crown base height to stem diameter relationships for the indigenous street tree species Combretum erythrophyllum, Rhus lancea andRhus pendulina, (2) to develop tree height, crown diameter, crown height, crown base height and stem diameter to tree age relationships for the above street tree species, (3) to determine the 30 year carbon sequestration estimate and monetary value of 115 000 street trees to be planted mainly in poorer previously disadvantaged communities during the period 2002 to 2008 and (4) to determine the monetary value of the 33 630 Jacaranda mimosifolia street trees in the City based on the quantity of carbon stored in the trees. Combretum erythrophyllum had the most rapid growth rate in many instances, thereafter came Rhus pendulina and then Rhus lancea, which consistently had the slowest growth rate for the investigated parameters. It is estimated that the 115 000 street trees to be planted will sequestrate more than 200 000 tonne CO2 equivalent and have an estimated monetary value of more than US$2 million if a market related CO2 price of US$10.00 per tonne is assumed. The Jacaranda street trees have an estimated carbon stock of 41 978 tonne CO2 equivalent and this would value the Jacaranda urban forest at US$419 786. Copyright / Thesis (PhD)--University of Pretoria, 2010. / Plant Science / unrestricted

Recent advances in retinal imaging have made it possible to take measurements of retinal oxygen saturation noninvasively in humans. This allows studying the supply of oxygen in healthy and diseased retinae, thereby advancing our understanding of both the normal functioning of the retina and of retinal pathologies. However, retinal oximetry is still a research tool only and requires further improvement before being used in a clinical setting. Here, a single-wavelength flickering light was used to increase retinal blood flow in healthy subjects. This increase is revealed by both vasodilation and an increase in retinal oxygen saturation. A flickering light stimulus provides the means to assess the sensitivity of any retinal oximetry system, as such systems should be able to pick up this increase in retinal blood flow. In addition, the flickering light allows for com- parison to be made within rather than between subjects and can be used to examine the activation of the eye. This reduces the influence of potential confounding factors between subjects including differences in fundus pigmentation and illumination. The most commonly used method to measure retinal oxygenation is the optical density ra- tio (ODR) approach. The standard approach is to compute the average ODR for each vessel segment by combining the hundreds of individual ODR readings and then to use the mean of these segment averages as a measure of oxygen saturation. Alternatively, it has been suggested that the peak location of Gaussian functions fitted to histograms of individual ODR readings can be used as an measure of retinal oxygenation. In response to a 10Hz flickering light, the venular diameter increased by 3.44% (SEM: ±0.53%) (n=16, p<0.05) and the arteriolar diameter by 1.87% (±0.72 %) (p<0.05). The optical density ratio, measured with the Gaussian fit, decreased in the venules from 0.713 (±0.015) to 0.694 (±0.015) (p<0.05). No changes in arteriolar optical density ratios were measured. The post-flicker measurement was computed as the average of up to four post-flicker datasets obtained at 10s, 20s, 30s and 40s after onset of flickering. These results suggest that the flickering light increased retinal blood flow. The mean absolute percentage error was lower in venules for the Gaussian fit method than for the gold standard method for datasets taken at 30s and 40s after onset of flickering. Thus, the Gaussian fit method was more robust. All measurements were taken with a custom-made retinal oximeter. The pixel intensity of the blood vessel and the intensity on either side of the vessel had to be extracted to compute the individual optical density ratios. This required the automatic extraction of the retinal vasculature. Two such algorithms were developed and applied to two databases of retinal fundus images: the DRIVE and the novel DR HAGIS database. One algorithm was purely based on the pixel intensities, while the other made use of oriented Gabor filters. These two algorithms segmented the images to a similar accuracy (DRIVE: 94.56% and 94.54%, DR HAGIS: 95.83% and 95.71% for the intensity and Gabor filter based algorithm, respectively) and performed as well as a human expert (DRIVE: 94.73%). These algorithms were of sufficient quality to extract individual segments for the oximetry study and to align fundus images.

Orientador: Anselmo Eduardo Diniz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T18:44:10Z (GMT). No. of bitstreams: 1 Krabbe_DanielFernandoMoreira_M.pdf: 4840835 bytes, checksum: 3db5447d6c84ae0db244c137740e2a84 (MD5) Previous issue date: 2006 / Resumo: No processo de desbaste, a máxima taxa de material removido por unidade de tempo (cm3 x min), dentro do intervalo de máxima eficiência, é o foco principal para as mais diversas empresas de usinagem. Afirmando este conceito, procurou-se neste trabalho obter para dois diferentes diâmetros de fresas inteiriças de metal duro, a máxima vida de ferramenta por volume removido de material, na usinagem da liga de aço inoxidável endurecível por precipitação 15-5 PH. As variáveis deste estudo foram os diâmetros da ferramenta (16 e 20 mm), a profundidade de corte ¿ap¿ (5 a 16 mm), a profundidade radial de corte ¿ae¿ (33%D e 77%D) a velocidade de corte ¿vc¿ (80 e 100 m/min). Mantiveram-se constantes o número de dentes da fresa, a classe do metal duro e revestimento, a espessura média de cavaco, o fluido de corte e a taxa de remoção de material para cada profundidade radial de corte. Os parâmetros de avaliação foram o desgaste de flanco ¿vb¿ da aresta principal de corte, a potência consumida e o comprimento de corte fresado por vida da ferramenta. Os resultados demonstram que a fresa de menor diâmetro (16 mm) apresentou sempre uma maior vida de ferramenta para a mesma taxa de remoção de material quando comparada à fresa de maior diâmetro (20 mm). Demonstram também que para a menor condição de profundidade radial de corte estudada a uma profundidade axial de corte elevada (baixo ¿ae¿ alto ¿ap¿), a vida da ferramenta é superior quando comparada à mesma condição de taxa de remoção de material, porém com profundidade radial alta (alto ¿ae¿ e baixo ¿ap¿) / Abstract: In the roughing machining process, the maximum removal rate (cm3 x min-1) inside of the maximum efficiency interval, is the main target of the most different machining shops. Based in this concept, the target of these experiments was to find for two different end mill diameters in the milling process, the maximum removal rate per tool life in the 15-5 precipitation hardening stainless steel alloy. The input variables of these experiments were the end mill diameter (16 and 20 mm), the depth of the cut ¿ap¿ (from 5 to16 mm), the radial depth of cut ¿ae¿ (33%D and 77%D) the cutting speed ¿vc¿ (80 and 100 m/min). The end mill number of teeth, the solid carbide and surface coating characteristics, the average chip thickness, the cutting fluid and the removal rate for each radial depth of cut were kept constants. The evaluation parameters were the wear on the main cutting edge, the spindle power and the work piece machined length. The analysis of results showed that for a smaller end mill diameter (16 mm) always a longer tool life was reached for the same removal volume rate when compared with the end mill with larger diameter (20 mm). It also shows that for a smaller radial depth of cut and big depth of cut (small ¿ae¿ large ¿ap¿), the tool life is higher than when compared with the same removal rate condition, however with larger radial depth of cut and smaller depth of cut (big ¿ae¿ small ¿ap¿) / Mestrado / Engenharia de Fabricação / Mestre em Engenharia Mecânica