Orientador: João Andrade de Carvalho Junior / Coorientador: Andreas Nascimento / Banca: Mauro Hugo Mathias / Banca: José Luiz Gonçalves / Abstract: To meet the increasing primary energy demand, more challenging petroleum reserves started being explored, such as the reservoirs from pre-salt formation close to the Brazilian and Angolan coasts. Historically, low penetration rates in drilling the pre-salt carbonates were reported in the literature, resulting in large capital expenditure on well's construction. Since the major part of exploration cost is associated with drilling, optimizing this activity is of major importance. In this context, the main objective of the present thesis is to investigate methods for real-time drilling optimization of oil and natural gas wells. A common way to optimize drilling activities is to determine the optimum operational variables (e.g. weight-on-bit and rotational speed) that maximizes the ROP. However, this may yield a decrease in drilling efficiency. An alternative to reduce problems related to drilling inefficiency, such as excessive bit wear and vibrations, is through the selection of operational variables able to minimize the specific energy (SE) spent to excavate a volumetric unit of rock. For that, it is necessary to employ accurate predictive models able to capture how the operational variables (weight-on-bit, rotational speed, mud flow and so on) influence not only on ROP but also on SE. Therefore, the present thesis employed a well-known machine learning method, called random forest, instead of analytical equations found in drilling engineering books. Thus, it was possible to o... (Complete abstract click electronic access below) / Resumo: Para atender à crescente demanda de energia primária, começaram a ser exploradas reservas de petróleo em áreas mais desafiadoras, tais como os reservatórios da formação do pré-sal próximos às costas brasileira e angolana. Historicamente, observa-se baixa taxa de penetração na perfuração dos carbonatos do pré-sal, resultando em altos custos na construção de poços. Como a maior parte dos custos de exploração está associado com perfuração, a otimização desta atividade é de grande importância. Neste contexto, o principal objetivo desta dissertação é investigar métodos de otimização em tempo-real de poços de petróleo e gás natural. Uma forma comum de se otimizar a perfuração é através da determinação dos parâmetros operacionais (peso na broca e rotação) que maximizem a taxa de penetração (rate of penetration, ROP). Contudo, isto pode acarretar na diminuição da eficiência do processo de perfuração. Assim, uma forma de diminuir problemas relacionadas a ineficiências da perfuração, tais como gasto excessivo da broca ou vibrações, é através da seleção dos parâmetros operacionais, minimizando a energia específica (specific energy, SE) gasta para escavar uma unidade volumétrica de rocha. Para tanto, é necessário o emprego de modelos precisos que relacionem como as variáveis operacionais (peso da broca, rotação, vazão do fluido de perfuração entre outros) influenciam, não somente o ROP, mas também a SE. Desde modo, a presente dissertação empregou um método conhecido de aprendizagem de má... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Modern tunnel boring machines require large drilling forces, and need to be fastened in the tunnel to generate such forces. The fastening of tunnel boring machines is traditionally accomplished by means of hydraulic cylinders that fasten and position the machine prior to drilling, known as grippers. A problem encountered in this solution is that the hydraulics suffers from an undesirably low stiffness, which makes the mechanism sensitive to vibrations generated by the drilling. Replacing the hydraulics with some kind of mechanical force transfer mechanismis believed to reduce said sensitivity. The purpose of the thesis is to develop a new gripper concept, evaluate if it is possible to substitute any of the hydraulic actuators with a mechanical counterpart, and assess if a mechanical solution increases the vertical stiffness of the grippers. The CAD-models were created in PRO/Engineer Wildfire 4.0 and the FEM-analysis was conducted using ANSYS Workbench 14.0. The calculations were done using MATLAB R2012a. With an extensive pre-study conducted, a number of gripper concepts were generated and evaluated (using a Pugh´s matrix), and a suggestion of a mechanical force transfer mechanism was created using the information from the concept evaluation. The most suitable force transfer method turned out to be a jack screw mechanism, thanks to its high load carrying capacity and self-locking characteristics. The jack screw will be powered using a hydraulic motor, ashydraulic power is easily accessible on the tunnel boring machine. The analysis conducted points to a significant increase in vertical stiffness, but also to an added degree of complexity which might not be fully desirable. An analysis of the dynamic behavior of the system would also be necessary to fully understand the component interactions. / Moderna tunnelborrningsmaskiner fordrar höga borrkrafter, och behöver fixeras i tunnelgången för att generera dessa. Inspänningen av tunnelborrningsmaskiner görs traditionellt med hydrauliska cylindrar som fixerar och positionerar maskinen inför borrningen, så kallade gripprar. Ett problem med denna metod är att hydrauliken har en viss vekhet som gör konstruktionen känslig för de vibrationer som borrningen skapar, och som eventuellt tros kunna reduceras med en mekanisk lösning. Syftet med detta examensarbete är att ta fram ett nytt gripperkoncept och utreda om det är möjligt att ersätta någon del av hydrauliken med en mekanisk kraftöverföring, för att öka denvertikala styvheten hos mekanismen. CAD-modellerna av koncepten skapades i PRO/EngineerWildfire 4.0 och FEM-analysen gjordes i ANSYS Workbench 14.0. För beräkningarna användes MATLAB R2012a. Med en omfattande förstudie genomförd togs ett antal gripperkoncept fram och utvärderades (med hjälp av Pughs matris), och ett förslag på en mekanisk kraftöverföringsmekanism genererades. Den mest lämpliga kraftöverföringen visade sig vara en skruvdomkraftsanordning,tack vare dess höga lastkapacitet och självhämmande beteende. Mekanismen avses drivas av en hydraulisk motor, då det är en kraftkälla som är lättillgänglig på maskinen. Analysen pekar på att styvheten i konstruktionen kan ökas avsevärt med en mekanisk kraftöverföring, men en sådan tillför också en viss komplexitet till konstruktionen som kanske inte är önskvärd. En analys av det dynamiska beteendet hos konstruktionen är också nödvändig för att till fullo kunna förutse mekanismens beteende.

To remain competitive in today’s demanding economy, there is an increasing demand for improved productivity and scrap reduction in manufacturing. Traditional manufacturing metal removal processes such as turning and boring are still one of the most used techniques for fabricating metal products. Although the essential metal removal process is the same, new advances in technology have led to improvements in the monitoring of the process allowing for reduction of power consumption, tool wear, and total cost of production. Replacing used CNC lathes from the 1980’s in a manufacturing facility may prove costly, thus finding a method to modernize the lathes is vital. This research focuses on Phase I and II of a three phase research project where the final goal is to optimize the simultaneous turning and boring operation of a CNC Lathe. From the optimization results it will be possible to build an adaptive controller that will produce parts rapidly while minimizing tool wear and machinist interaction with the lathe. Phase I of the project was geared towards selecting the sensors that were to be used to monitor the operation and designing a program with an architecture that would allow for simultaneous data collection from the selected sensors at high sampling rates. Signals monitored during the operation included force, temperature, vibration, sound, acoustic emissions, power, and metalworking fluid flow rates. Phase II of this research is focused on using the Response Surface Method to build empirical models for various responses and to optimize the simultaneous cutting process. The simultaneous turning and boring process was defined by the four factors of spindle speed, feed rate, outer diameter depth of cut, and inner diameter depth of cut. A total of four sets of experiments were performed. The first set of experiments screened the experimental region to iii determine if the cutting parameters were feasible. The next three set s of designs of experiments used Central Composite Designs to build empirical models of each desired response in terms of the four factors and to optimize the process. Each design of experiments was compared with one another to validate that the results achieved were accurate within the experimental region. By using the Response Surface Method optimal machining parameter settings were achieved. The algorithm used to search for optimal process parameter settings was the desirability function. By applying the results from this research to the manufacturing facility, they will achieve reduction in power consumption, reduction in production time, and decrease in the total cost of each part.

Manufacturing operations generate revenue by adding value to material through machine work and the cost associated with part production hinders the maximum profit available. In order to remain competitive, companies invest in research to maximize profit and reduce waste of manufacturing operations. This results in cheaper products for the customer without sacrificing quality. The purpose of this research was to identify machine settings of an Okuma LC 40 Turning Center and optimize the cost of machining in terms of tool cost and energy consumption while maintaining part quality at a productive cycle time. Studying the relationship between energy consumption, tool life, and cycle time with the speed and feed settings through statistical Analysis of Variance (ANOVA) method will allow the production plant to make profitable financial decisions concerning simultaneous turning operation of forged chrome-alloy steel. The project was divided into three phases; the first phase began with a literature survey of sensors used in current manufacturing research and the adaptation of our sensors to the Okuma LC 40 turning center. Then, phase II used design of experiments to identify spindle speed and feedrate settings that optimize multiple responses related to the turning process. The result was a saving in energy consumption (kWh) by 11.8%, a saving in cutting time by 13.2% for a total cost reduction from $1.15 per tool pass to $1.075 per tool pass. Furthermore, this work provides the foundation for phase III to develop an intelligent monitoring system to provide real-time information about the state of the machine and tool. For a monitoring system to be implemented in production, it should utilize cost effective sensors and be nonintrusive to the cutting operation

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13547号 / 論農博第2912号 / 新制||農||1101(附属図書館) / 学位論文||R5||N5428(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 大村 和香子, 教授 井鷺 裕司, 教授 今井 友也 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Production of fine sediments in reef environments is a poorly understood but probably significant process. On the Great Barrier Reef, Cliona viridis is locally abundant. The sponge has been found from Lizard Island in the north, down to the southern part of the Central Region, and it is likely even more widespread. Although on individual reefs the sponge may occur almost anywhere, it is most abundant on lagoon path reefs ("bommies" in Australian), where it overgrows the substrate and bores to a constant depth of about 1.3cm. Sponge infestation reaches a maximum at a depth of 4 m covering almost 8% of the vertical sides of bommies. It is frequently the dominant benthic organism. Serial underwater photography demonstrates that colonies can expand laterally at a rate of about 1 cm yr⁻¹ removing approximately 40% of the substrate. This species is a major producer of fine sediment on the Great Barrier Reef. / Thesis / Master of Science (MS)

O processo convencional de furação é um dos processos de usinagem empregado em larga escala, normalmente utilizado em operações com menor responsabilidade na qualidade superficial dos furos usinados, atingindo perfis de rugosidade na ordem de 6,3 Ra. Para processos mais refinados, que atinjam 0,8 Ra, por exemplo, opta-se por processos de alargamento, mandrilamento, entre outros, que são mais onerosos em relação aos custos com ferramentas de corte e, principalmente, o tempo de operação. Na tentativa de reduzir o tempo de usinagem melhorando a qualidade dos furos obtidos nestes processos, fabricantes de ferramentas vêm desenvolvendo e aprimorando geometrias capazes de conjugar as operações de furação com operações de alargamento, obtendo resultados expressivos do ponto de vista de produtividade. As brocas alargadoras, entre outras características, são fabricadas com maior número de gumes de corte, chegando a oito de acordo com o diâmetro da ferramenta. Os canais principais têm a função de desbaste e alta remoção de cavaco, enquanto os outros canais atuam de forma a reduzir a rugosidade, removendo pouco material e proporcionando maior estabilidade para a ferramenta durante a usinagem. O objetivo desse trabalho é estudar o comportamento do processo de usinagem por brocas alargadoras de quatro e seis cortes na obtenção de furos com valores máximos de rugosidade até 0,8 Ra no material ferro fundido GG30, comparando os resultados com o processo de alargamento convencional. Os resultados preliminares demonstraram que, utilizando as brocas alargadoras, consegue-se redução superior a 30% no tempo de usinagem, quando comparado ao processo convencional de alargamento, mantendo valores de rugosidade na ordem de 0,8 Ra, unindo a velocidade de um processo convencional de furação com a qualidade superficial dos furos obtidos nos processos convencionais de alargamento. / The conventional drilling process is the most used among all machining processes. It is usually applied for holes with lower quality surface requirement, with roughness around 6.3 Ra. Higher quality drilling process, with 0,8 Ra, use other drilling process such as, reaming, boring, among others. These processes are more expensive because of the cost of cutting tools and especially because of the operational time. Aiming to reducing the machining time and improve the holes surface quality, tool manufacturers have been developing and improving geometries able to combine the drilling operations with reaming operations, optimizing the productivity. The drill reamers, among other characteristics, are manufactured with the highest number of cutting edges, usually with eight edges based on tool’s diameter. The main channel have high trimming functions and high chip removal, while the other channel reduce the surface roughness, removing less material and providing greater tools stability during the machining process. The aim of this paper is to study the behavior of the machining process through drill reamers with four and six cutting edges, taken into consideration holes with roughness up to o,8 Ra in the material cast iron GG30, comparing this performance with conventional reamers’ process. The preliminary results has indicated that by using drill reamers, over 30% of the machining time can be reduced comparing to conventional reamers’ process, keeping roughness values around 0,8Ra, merging the speed of conventional drilling’ process with the surface quality of the holes obtained in conventional reamers’ processes.

No description available.

A study of the Strategic Sewage Disposal Scheme (SSDS) Stage 1 Tunnel F in Hong Kong was carried out as it is a great example of deep sub-sea hard rock TBM tunnelling through unfavourable, fault-affected ground conditions with heavy water inflows. The main objective of this study was to document events that took place during Tunnel F excavation and collate geological and geotechnical data related to the excavation, to aid future tunnel designers and contractors to assess the risk involved with such tunnelling projects. Data relevant to Tunnel F was collected from many personnel involved with the excavation, and from the Hong Kong Geological Survey (HKGS) of the Geotechnical Engineering Office. Geological maps, ground investigation data, tunnel mapping records, ground water inflow records and grouting records were reviewed and used to summarise the ground conditions and to analyse various potential relationships. Knowledge of ground conditions is the most important requirement for any tunnelling project. This dissertation addresses the differences between actual and predicted ground conditions and the consequences of lack of ground investigation data. The major difference between predicted and observed ground conditions during Tunnel F excavation was the amount of water ingress into the tunnel. Hundreds of liters per minute of water at up to 13bar pressure was encountered from a few probe and grout holes. In the Tolo Channel Fault area, low Q values and very high ground water inflows were experienced, and heavy temporary support and large grout volumes were required to complete the tunnel. / published_or_final_version / Applied Geosciences / Master / Master of Science

With the advent of the large diameter tunnel boring machine (TBM), mechanically driven large diameter tunnel is becoming a more attractive option. During operation, a large diameter tube allows for stacked deck configuration with shafts dropped to platform level (no station caverns). The extensive information has been compiled on innovative TBM tunneling projects such as the Barcelona Line 9, where the concept of continuous station has been used for the first time, stormwater management and roadway tunnel in Malaysia, where the floodwater bypass tunnel and the road tunnel are incorporated in a single bore tunnel. The decision making process that led to the construction of large bore tunnel is also presented. A detailed study has been carried out to determine the necessary face support pressure in drained conditions (with ideal membrane), and undrained conditions. The effects of tunnel diameter, cover-to-diameter ratio, at-rest lateral earth pressure coefficient, and soil shear strength parameters on the local and global stability of the excavation face of mechanically-driven tunnels have been investigated. The relation between the face support pressure and the calculated tunnel face displacement gave the minimum face support pressure that should be applied on the tunnel face to avoid abrupt movement of the tunnel face. Simple expressions have been developed for the support pressure as a function of tunnel diameter, cover depth, lateral earth pressure coefficient, and soil strength parameters. The required face support pressures are compared to the analytical solutions available from the literature. It has been found that analytical stability solutions generally underestimate the required face support pressure and excessive deformation will take place in the ground near the tunnel heading when these solutions are used. By using plastic limit analysis, a rigid and deformable prism-and-wedge model has been developed; in undrained conditions, upper bound solutions against collapse load are derived for face pressure. Deformable blocks enabled to take into account the effect of non-uniform support pressure due to the unit weight of the supporting medium. The upper bound solution derived as a function of tunnel diameter and cover depth, normalized undrained shear strength ratio, and unit weight of the ground and the supporting medium was compared with a solution available from the literature. Largest face support pressure was obtained when the uniform face support pressure was applied and it was smallest when identical unit weight was used for the ground and the supporting medium. / text