A smart micro-drill for cochleostomy formation:a comparison of cochlear disturbances with manual drilling and a human trial

Background: Cochleostomy formation is a key stage of the cochlear implantation procedure. Minimizing the trauma sustained by the cochlea during this step is thought to be a critical feature in hearing preservation cochlear implantation. The aim of this paper is firstly, to assess the cochlea disturbances during manual and robotic cochleostomy formation. Secondly, to determine whether the use of a smart micro-drill is feasible during human cochlear implantation. Materials and methods: The disturbances within the cochlea during cochleostomy formation were analysed in a porcine specimen by creating a third window cochleostomy, preserving the underlying endosteal membrane, on the anterior aspect of the basal turn of the cochlea. A laser vibrometer was aimed at this third window, to assess its movement while a traditional cochleostomy was performed. Six cochleostomies were performed in total, three manually and three with a smart micro-drill. The mean and peak membrane movement was calculated for both manual and smart micro-drill arms, to represent the disturbances sustained within cochlea during cochleostomy formation. The smart micro-drill was further used to perform live human robotic cochleostomies on three adult patients who met the National Institute of Health and Clinical Excellence criteria for undergoing cochlear implantation. Results: In the porcine trial, the smart micro-drill preserved the endosteal membrane in all three cases. The velocity of movement of the endosteal membrane during manual cochleostomy is approximately 20 times higher on average and 100 times greater in peak velocity, than for robotic cochleostomy. The robot was safely utilized in theatre in all three cases and successfully created a bony cochleostomy while preserving the underlying endosteal membrane. Conclusions: Our experiments have revealed that controlling the force of drilling during cochleostomy formation and opening the endosteal membrane with a pick will minimize the trauma sustained by the cochlea by a factor of 20. Additionally, the smart micro-drill can safely perform a bony cochleostomy in humans under operative conditions and preserve the integrity of the underlying endosteal membrane. © W. S. Maney & Son Ltd 2013.

Aspectos da furação do titânio 6Al4V com broca de aço rápido sinterizado e broca de metal duro

Pós-graduação em Engenharia Mecânica - FEG

Concepção detalhada de uma bancada para simular esforços mecânicos em colunas de perfuração

In this work we study the construction of a test rig made to simulate the Mechanical efforts in wich a drillstring is submitted. The model is based on the rig built at IDS, Germany. There are some fault liabilities while doing the project of the axis. Therefore it's important to analyze and take knowledge of this efforts in order to predict failures like rupture or fatigue collapse. The main objective of this theis is to show the operating principle of the test rig and it's construction. The accomplished study allow us to predict the drillstring behavior and from the economic point of view that is very important because failures results in equipments maintenance that requires time and money causing prejudice to the company. Using SolidWorks, a simulation software, the thesis approaches all the mechanical parts required for it's construction as well as it's working principle. Acquisition sensors like strain gauges, accelerometer, and torque transductor were also used in this model. The objective of this thesis is to create a simulation model to be eventually at FEG(UNESP). During the development of the study, it was possible to learn more about the drilling process and the mechanical efforts in which the drill pipe is submitted. The accomplished contributed with knowledge for the student in the drilling process area. Also during the development of the study it was possible to have contact with different areas of engineering but the study is specifically directed to the construction of the test rig. Therefore the main theme of this thesis is to show the operating principle of the test rig and it's construction

Concepção detalhada de uma bancada para simular esforços mecânicos em colunas de perfuração

In this work we study the construction of a test rig made to simulate the Mechanical efforts in wich a drillstring is submitted. The model is based on the rig built at IDS, Germany. There are some fault liabilities while doing the project of the axis. Therefore it's important to analyze and take knowledge of this efforts in order to predict failures like rupture or fatigue collapse. The main objective of this theis is to show the operating principle of the test rig and it's construction. The accomplished study allow us to predict the drillstring behavior and from the economic point of view that is very important because failures results in equipments maintenance that requires time and money causing prejudice to the company. Using SolidWorks, a simulation software, the thesis approaches all the mechanical parts required for it's construction as well as it's working principle. Acquisition sensors like strain gauges, accelerometer, and torque transductor were also used in this model. The objective of this thesis is to create a simulation model to be eventually at FEG(UNESP). During the development of the study, it was possible to learn more about the drilling process and the mechanical efforts in which the drill pipe is submitted. The accomplished contributed with knowledge for the student in the drilling process area. Also during the development of the study it was possible to have contact with different areas of engineering but the study is specifically directed to the construction of the test rig. Therefore the main theme of this thesis is to show the operating principle of the test rig and it's construction

Suggested unit course in drill press work for beginners in machine shop practice ...

Prepared by Ewald L. Witzel and C. Thomas Olivo. cf. 5th prelim. leaf.

The Cleveland Twist Drill Co. : manufacturers of drills, reamers, screw extractors, arbors, mandrels, sockets, mills, counterbores, high speed tools : catalog 39.

Includes indexes.

An investigation of the relationship between temperature, forces and tool wear in turning and drilling

Developing a means of predicting tool life has been and continues to be a focus of much research effort. A common experience in attempting to replicate such efforts is an inability to achieve the levels of agreement between theory and practice of the original researcher or to extrapolate the work to different materials or cutting conditions to those originally used. This thesis sets out to examine why most equations or models when replicated do not give good agreements. One reason which was found is that researchers in wear prediction, their predictions are limited because they generally fail to properly identify the nature of wear mechanisms operative in their study. Also they fail to identify or recognise factors having a significant influence on wear such as bar diameter. Also in this research the similarities and differences between the two processes of single point turning and drilling are examined through a series of tests. A literature survey was undertaken in wear and wear prediction. As a result it was found that there was a paucity in information and research in the work of drilling as compared to the turning operation. This was extended to the lack of standards that exist for the drilling operation. One reason for this scarcity in information on drilling is due to the complexity of the drilling and the tool geometry of the drill. In the comparative drilling and turning tests performed in this work, the same tool material; HSS, and similar work material was used in order to eliminate the differences which may occur due to this factor. Results of the tests were evaluated and compared for the two operations and SEM photographs were taken for the chips produced. Specific test results were obtained for the cutting temperatures and forces of the tool. It was found that cutting temperature is influenced by various factors like tool geometry and cutting speed, and the temperature itself influenced the tool wear and wear mechanisms that act on the tool. It was found and proven that bar diameter influences the temperature, a factor not considered previously.

Humanistic science education : moves from within and challenges from without

For a number of years now it has been evident that the major issue facing science educators in the more developed countries of the world is the quantitative decline in enrolments in the senior secondary sciences, particularly the physical sciences, and in the number of higher achieving students applying for places in universities to undertake further studies in science. The deep malaise in school science to which these quantitative measures point has been elucidated by more qualitative studies of the students’ experience of studying science in secondary school in several of these countries (Sweden, Lindahl (2003); England, Simon and Osborne (2002); and Australia, Lyons (2005)). Remarkably concordant descriptions of these experiences can be summarized as: School science is: • transmission of knowledge from the teacher or the textbook to the students. • about content that is irrelevant and boring to our lives. • difficult to learn in comparison with other subjects Incidentally, the Australian study only involved consistently high achieving students; but even so, most of them found science more difficult than other more interesting subjects, and concluded that further science studies should be avoided unless they were needed for some career purpose. Other more representative confirmations of negative evaluations of the science curricula across Australia (and in particular states) are now available in Australia, from the large scale reviews of Goodrum, Hackling and Rennie (2001) and from the TIMSS (2002). The former reported that well under half of secondary students find the science at school relevant to my future, useful ion everyday life, deals with things I am concerned with and helps me make decisions about my health.. TIMSS found that 62 and 65 % of females and males in Year 4 agree with I like learning science, but by Year 8 only 26 and 33 % still agree. Students in Japan have been doubly notably because of (a) their high performance in international measures of science achievement like TIMSS and PISA and (b) their very low response to items in these studies which relate to interest in science. Ogura (2003) reported an intra-national study of students across Years 6-9 (upper primary through Junior High); interest in a range of their subjects (including science) that make up that country’s national curriculum. There was a steady decline in interest in all these subjects which might have indicated an adolescent reaction against schooling generally. However, this study went on to ask the students a further question that is very meaningful in the Japanese context, If you discount the importance of this subject for university entrance, is it worth studying? Science and mathematics remained in decline while all the other subjects were seen more positively. It is thus ironic, at a time when some innovations in curriculum and other research-based findings are suggesting ways that these failures of school science might be corrected, to find school science under a new demands that come from quite outside science education, and which certainly do not have the correction of this malaise as a priority. The positive curricular and research findings can be characterized as moves from within science education, whereas the new demands are moves that come from without science education. In this paper I set out these two rather contrary challenges to the teaching of science as it is currently practised, and go on to suggest a way forward that could fruitfully combine the two.

A study of environmental and management drivers of non-CO2 greenhouse gas emissions in Australian agro-ecosystems

Australian climate, soils and agricultural management practices are significantly different from those of the northern hemisphere nations. Consequently, experimental data on greenhouse gas production from European and North American agricultural soils and its interpretation are unlikely to be directly applicable to Australian systems. A programme of studies of non-CO2 greenhouse gas emissions from agriculture has been established that is designed to reduce uncertainty of non-CO2 greenhouse gas emissions in the Australian National Greenhouse Gas Inventory and provide outputs that will enable better on-farm management practices for reducing non-CO2 greenhouse gas emissions, particularly nitrous oxide. The systems being examined and their locations are irrigated pasture (Kyabram Victoria), irrigated cotton (Narrabri, NSW), irrigated maize (Griffith, NSW), rain-fed wheat (Rutherglen, Victoria) and rain-fed wheat (Cunderdin, WA). The field studies include treatments with and without fertilizer addition, stubble burning versus stubble retention, conventional cultivation versus direct drilling and crop rotation to determine emission factors and treatment possibilities for best management options. The data to date suggest that nitrous oxide emissions from nitrogen fertilizer, applied to irrigated dairy pastures and rain-fed winter wheat, appear much lower than the average of northern hemisphere grain and pasture studies. More variable emissions have been found in studies of irrigated cotton/vetch/wheat rotation and substantially higher emissions from irrigated maize.

A USANS/SANS study of the accessibility of pores in the barnett shale to methane and water

Shale is an increasingly important source of natural gas in the United States. The gas is held in fine pores that need to be accessed by horizontal drilling and hydrofracturing techniques. Understanding the nature of the pores may provide clues to making gas extraction more efficient. We have investigated two Mississippian Barnett Shale samples, combining small-angle neutron scattering (SANS) and ultrasmall-angle neutron scattering (USANS) to determine the pore size distribution of the shale over the size range 10 nm to 10 μm. By adding deuterated methane (CD4) and, separately, deuterated water (D2O) to the shale, we have identified the fraction of pores that are accessible to these compounds over this size range. The total pore size distribution is essentially identical for the two samples. At pore sizes >250 nm, >85% of the pores in both samples are accessible to both CD4 and D2O. However, differences in accessibility to CD4 are observed in the smaller pore sizes (∼25 nm). In one sample, CD4 penetrated the smallest pores as effectively as it did the larger ones. In the other sample, less than 70% of the smallest pores (<25 nm) were accessible to CD4, but they were still largely penetrable by water, suggesting that small-scale heterogeneities in methane accessibility occur in the shale samples even though the total porosity does not differ. An additional study investigating the dependence of scattered intensity with pressure of CD4 allows for an accurate estimation of the pressure at which the scattered intensity is at a minimum. This study provides information about the composition of the material immediately surrounding the pores. Most of the accessible (open) pores in the 25 nm size range can be associated with either mineral matter or high reflectance organic material. However, a complementary scanning electron microscopy investigation shows that most of the pores in these shale samples are contained in the organic components. The neutron scattering results indicate that the pores are not equally proportioned in the different constituents within the shale. There is some indication from the SANS results that the composition of the pore-containing material varies with pore size; the pore size distribution associated with mineral matter is different from that associated with organic phases.

Towards groundwater security in coastal East Africa: initiating a regional research network and integrated hydrogeologic, climatic & socio-economic observatories in coastal aquifers of the Comoros Islands, Kenya and Tanzania

African coastal regions are expected to experience the highest rates of population growth in coming decades. Fresh groundwater resources in the coastal zone of East Africa (EA) are highly vulnerable to seawater intrusion. Increasing water demand is leading to unsustainable and ill-planned well drilling and abstraction. Wells supplying domestic, industrial and agricultural needs are or have become, in many areas, too saline for use. Climate change, including weather changes and sea level rise, is expected to exacerbate this problem. The multiplicity of physical, demographic and socio-economic driving factors makes this a very challenging issue for management. At present the state and probable evolution of coastal aquifers in EA are not well documented. The UPGro project 'Towards groundwater security in coastal East Africa' brings together teams from Kenya, Tanzania, Comoros Islands and Europe to address this knowledge gap. An integrative multidisciplinary approach, combining the expertise of hydrogeologists, hydrologists and social scientists, is investigating selected sites along the coastal zone in each country. Hydrogeologic observatories have been established in different geologic and climatic settings representative of the coastal EA region, where focussed research will identify the current status of groundwater and identify future threats based on projected demographic and climate change scenarios. Researchers are also engaging with end users as well as local community and stakeholder groups in each area in order to understanding the issues most affecting the communities and searching sustainable strategies for addressing these.

Tool life and hole surface integrity studies for hole-making of Ti6Al4V Alloy

With a significant growth in the use of titanium alloys in the aviation manufacturing industry, the key challenge of making high-quality holes in the aircraft assembly process needs to be addressed. In this work, case studies deploying traditional drilling and helical milling technologies are carried out to investigate the tool life and hole surface integrity for hole-making of titanium alloy. Results show that the helical milling process leads to much longer tool life, generally lower hole surface roughness, and higher hole subsurface microhardness. In addition, no plastically deformed layer or white layer has been observed in holes produced by helical milling. In contrast, a slightly softened region was always present on the drilled surface. The residual stress distributions within the hole surface, including compressive and tensile residual stress, have also been investigated in detail.

Hole-making Process and Its impacts on the Fatigue Response of Ti -6Al-4V Aircraft Alloy

In this work, the impact of conventional drilling and helical milling processes on the fatigue response Ti-6Al-4V (grade 5 titanium alloy) has been presented. Results show that the work pieces produced by helical milling has a 119% longer fatigue life compared with the drilled pieces under dry machining condition, and a 96% longer fatigue life for helical milled piece under lubricated condition. The use of cutting fluid has led to longer fatigue lives – 15% longer for drilling and 3% longer for helical milling. Other results such as the machined surface roughness, alloy surface and sub-surface microstructures have also been studied in details.

Seafloor geological impacts associated with drilling disturbance

This study describes the sedimentological composition and morphology of the sea bottom in an area located at 902 m depth in the Campos Basin of Brazil, and compares characteristics before and after drilling activity for oil exploration. The results show no significant sedimentological variation in the area affected by drilling. The most noticeable effects were observed during the second (MD(2)) of three cruises, in terms of change to grain size distribution, total organic carbon and clay mineral composition around the Eagle well. This impact occurred over the seabed in a direction that corresponds to the near-bottom circulation pattern, predominantly northward. In the third cruise (MD3), 12 months after drilling, some recovery was observed. Side-scan sonar imaging was used to explore the extent of the area affected by drilling, and sedimentological samples from it confirmed the effects of drilling. (C) 2008 Elsevier Ltd. All rights reserved.

Impact of Bone Harvesting Techniques on Cell Viability and the Release of Growth Factors of Autografts

Background: Autogenous bone grafts obtained by different harvesting techniques behave differently during the process of graft consolidation; the underlying reasons are however not fully understood. One theory is that harvesting techniques have an impact on the number and activity of the transplanted cells which contribute to the process of graft consolidation. Materials and Methods: To test this assumption, porcine bone grafts were harvested with four different surgical procedures: bone mill, piezosurgery, bone drilling (bone slurry), and bone scraper. After determining cell viability, the release of molecules affecting bone formation and resorption was assessed by reverse transcription polymerase chain reaction and immunoassay. The mitogenic and osteogenic activity of the conditioned media was evaluated in a bioassay with isolated bone cells. Results: Cell viability and the release of molecules affecting bone formation were higher in samples harvested by bone mill and bone scraper when compared with samples prepared by bone drilling and piezosurgery. The harvesting procedure also affected gene expression, for example, bone mill and bone scraper samples revealed significantly higher expression of growth factors such as bone morphogenetic protein-2 and vascular endothelial growth factor compared with the two other modalities. Receptor activator of nuclear factor kappa B ligand expression was lowest in bone scraper samples. Conclusion: These data can provide a scientific basis to better understand the impact of harvesting techniques on the number and activity of transplanted cells, which might contribute to the therapeutic outcome of the augmentation procedure.