Digital Urban - The Visual City

Nothing in the city is experienced by itself for a city’s perspicacity is the sum of its surroundings. To paraphrase Lynch (1960), at every instant, there is more than we can see and hear. This is the reality of the physical city, and thus in order to replicate the visual experience of the city within digital space, the space itself must convey to the user a sense of place. This is what we term the “Visual City”, a visually recognisable city built out of the digital equivalent of bricks and mortar, polygons, textures, and most importantly data. Recently there has been a revolution in the production and distribution of digital artefacts which represent the visual city. Digital city software that was once in the domain of high powered personal computers, research labs and professional software are now in the domain of the public-at-large through both the web and low-end home computing. These developments have gone hand in hand with the re-emergence of geography and geographic location as a way of tagging information to non-proprietary web-based software such as Google Maps, Google Earth, Microsoft’s Virtual Earth, ESRI’s ArcExplorer, and NASA’s World Wind, amongst others. The move towards ‘digital earths’ for the distribution of geographic information has, without doubt, opened up a widespread demand for the visualization of our environment where the emphasis is now on the third dimension. While the third dimension is central to the development of the digital or visual city, this is not the only way the city can be visualized for a number of emerging tools and ‘mashups’ are enabling visual data to be tagged geographically using a cornucopia of multimedia systems. We explore these social, textual, geographical, and visual technologies throughout this chapter

Wax removal using pipeline pigs

The deposition of paraffin wax solids in pipelines and risers represents a continuing challenge to flow assurance in offshore installations. Wax deposits reduce product throughput, requiring increased energy expenditure to re-establish flow levels. In severe cases, wax deposits can completely block a pipeline. Preventative solutions to the problem such as pipeline insulation, active heating of pipes or chemical dosing with wax inhibitors are not always economically viable, so mechanical removal using a device known as a 'pig' remains an economical solution to the problem of wax removal. A pig is a cylindrical tool that is driven through the pipe by the flow of product, scraping deposits from the pipe wall as it travels. Despite the importance of pipeline pigging to the oil and gas industry, the effectiveness of pigs in removing wax is poorly understood and it is this problem that is addressed by this thesis. One of the first necessities in undertaking this work has been to define the mechanical properties of wax deposits. This has required critical analysis of published material on the subject of wax deposition along with practical experimentation to create representative models of wax deposits that require mechanical removal from pipelines. Previously, studies of wax removal using pigs have assumed the mechanics of the process to be adequately represented by uniaxial compression or simple shear load models. In this work wax removal is analysed using the orthogonal cutting model. This provides a more accurate description of the process as it includes the effect of material after yielding (the chip) on the net wax removal force. Experiments were designed to allow testing of the validity of the orthogonal cutting theory to the pigging process under a variety of conditions. An original contribution from this work is through experimental and theoretical results that are given context through comparison with established metal cutting theory. Through experimentation a specific cutting energy is obtained for wax removal. The results of the wax cutting experiments have identified particular differences between wax cutting and metal cutting regarding the homogeneity of chip formation. These observations have important implications in predicting wax removal forces using mechanical removal tools. Although the affect of removed wax chips on pigging forces has been neglected in theory, it is well known in practice. The fluid used to drive cleaning pigs is often used to produce a jet radiating centrally from the front of the pig intended to blast wax chips away from the pig body, avoiding formation of a 'plug' of wax ahead of the pig. In this study a novel variation of this process in the form of an annular bypass jet is experimentally studied. A semi-empirical model of wax removal using an annular bypass jet has been developed and empirical constants obtained to allow prediction of removal rates for different waxes under various conditions. The new model introduced here allows balancing of pig velocity with wax removal velocity so that a non-contacting wax removal system is obtainable. The bypass-jetting model has been validated using a full-scale trial of the process by industrial sponsors

Machine learning and interactive real-time simulation for training on relevant total hip replacement skills.

Virtual Reality simulators have proven to be an excellent tool in the medical sector to help trainees mastering surgical abilities by providing them with unlimited training opportunities. Total Hip Replacement (THR) is a procedure that can benefit significantly from VR/AR training, given its non-reversible nature. From all the different steps required while performing a THR, doctors agree that a correct fitting of the acetabular component of the implant has the highest relevance to ensure successful outcomes. Acetabular reaming is the step during which the acetabulum is resurfaced and prepared to receive the acetabular implant. The success of this step is directly related to the success of fitting the acetabular component. Therefore, this thesis will focus on developing digital tools that can be used to assist the training of acetabular reaming. Devices such as navigation systems and robotic arms have proven to improve the final accuracy of the procedure. However, surgeons must learn to adapt their instrument movements to be recognised by infrared cameras. When surgeons are initially introduced to these systems, surgical times can be extended up to 20 minutes, maximising surgical risks. Training opportunities are sparse, given the high investment required to purchase these devices. As a cheaper alternative, we developed an Augmented Reality (AR) alternative for training on the calibration of imageless navigation systems (INS). At the time, there were no alternative simulators that using head-mounted displays to train users into the steps to calibrate such systems. Our simulator replicates the presence of an infrared camera and its interaction with the reflecting markers located on the surgical tools. A group of 6 hip surgeons were invited to test the simulator. All of them expressed their satisfaction with the ease of use and attractiveness of the simulator as well as the similarity of interaction with the real procedure. The study confirmed that our simulator represents a cheaper and faster option to train multiple surgeons simultaneously in the use of Imageless Navigation Systems (INS) than learning exclusively on the surgical theatre. Current reviews on simulators for orthopaedic surgical procedures lack objective metrics of assessment given a standard set of design requirements. Instead, most of them rely exclusively on the level of interaction and functionality provided. We propose a comparative assessment rubric based on three different evaluation criteria. Namely immersion, interaction fidelity, and applied learning theories. After our assessment, we found that none of the simulators available for THR provides an accurate interactive representation of resurfacing procedures such as acetabular reaming based on force inputs exerted by the user. This feature is indispensable for an orthopaedics simulator, given that hand-eye coordination skills are essential skills to be trained before performing non-reversible bone removal on real patients. Based on the findings of our comparative assessment, we decided to develop a model to simulate the physically-based deformation expected during traditional acetabular reaming, given the user’s interaction with a volumetric mesh. Current interactive deformation methods on high-resolution meshes are based on geometrical collision detection and do not consider the contribution of the materials’ physical properties. By ignoring the effect of the material mechanics and the force exerted by the user, they become inadequate for training on hand- eye coordination skills transferable to the surgical theatre. Volumetric meshes are preferred in surgical simulation to geometric ones, given that they are able to represent the internal evolution of deformable solids resulting from cutting and shearing operations. Existing numerical methods for representing linear and corotational FEM cuts can only maintain interactive framerates at a low resolution of the mesh. Therefore, we decided to train a machine-learning model to learn the continuum mechanic laws relevant to acetabular reaming and predict deformations at interactive framerates. To the best of our knowledge, no research has been done previously on training a machine learning model on non-elastic FEM data to achieve results at interactive framerates. As training data, we used the results from XFEM simulations precomputed over 5000 frames for plastic deformations on tetrahedral meshes with 20406 elements each. We selected XFEM simulation as the physically-based deformation ground-truth given its accuracy and fast convergence to represent cuts, discontinuities and large strain rates. Our machine learning-based interactive model was trained following the Graph Neural Networks (GNN) blocks. GNNs were selected to learn on tetrahedral meshes as other supervised-learning architectures like the Multilayer perceptron (MLP), and Convolutional neural networks (CNN) are unable to learn the relationships between entities with an arbitrary number of neighbours. The learned simulator identifies the elements to be removed on each frame and describes the accumulated stress evolution in the whole machined piece. Using data generated from the results of XFEM allowed us to embed the effects of non-linearities in our interactive simulations without extra processing time. The trained model executed the prediction task using our tetrahedral mesh and unseen reamer orientations faster per frame than the time required to generate the training FEM dataset. Given an unseen orientation of the reamer, the trained GN model updates the value of accumulated stress on each of the 20406 tetrahedral elements that constitute our mesh during the prediction task. Once this value is updated, the tetrahedrons to be removed from the mesh are identified using a threshold condition. After using each single-frame output as input for the following prediction repeatedly for up to 60 iterations, our model can maintain an accuracy of up to 90.8% in identifying the status of each element given their value of accumulated stress. Finally, we demonstrate how the developed estimator can be easily connected to any game engine and included in developing a fully functional hip arthroplasty simulator

A Numerical and Experimental Investigation of the Effects of Cutting Fluid on Machining Performance

Cutting fluids play an important role in improving machining performance. However, cutting fluids have adverse effects on health and environment. A new methodology has been proposed for the prediction of tool temperature and the experimentally validated methodology revealed that turning operations can be performed with reduced amount of cutting fluid. Followed by, experiments were conducted and the results demonstrated that the reduce amount of cutting fluid is sufficient to obtain acceptable machining performance

Chip Production Rate and Tool Wear Estimation in Micro-EndMilling

abstract: In this research, a new cutting edge wear estimator for micro-endmilling is developed and the reliabillity of the estimator is evaluated. The main concept of this estimator is the minimum chip thickness effect. This estimator predicts the cutting edge radius by detecting the drop in the chip production rate as the cutting edge of a micro- endmill slips over the workpiece when the minimum chip thickness becomes larger than the uncut chip thickness, thus transitioning from the shearing to the ploughing dominant regime. The chip production rate is investigated through simulation and experiment. The simulation and the experiment show that the chip production rate decreases when the minimum chip thickness becomes larger than the uncut chip thickness. Also, the reliability of this estimator is evaluated. The probability of correct estimation of the cutting edge radius is more than 80%. This cutting edge wear estimator could be applied to an online tool wear estimation system. Then, a large number of cutting edge wear data could be obtained. From the data, a cutting edge wear model could be developed in terms of the machine control parameters so that the optimum control parameters could be applied to increase the tool life and the machining quality as well by minimizing the cutting edge wear rate. In addition, in order to find the stable condition of the machining, the stabillity lobe of the system is created by measuring the dynamic parameters. This process is needed prior to the cutting edge wear estimation since the chatter would affect the cutting edge wear and the chip production rate. In this research, a new experimental set-up for measuring the dynamic parameters is developed by using a high speed camera with microscope lens and a loadcell. The loadcell is used to measure the stiffness of the tool-holder assembly of the machine and the high speed camera is used to measure the natural frequency and the damping ratio. From the measured data, a stability lobe is created. Even though this new method needs further research, it could be more cost-effective than the conventional methods in the future.Dissertation/ThesisDoctoral Dissertation Mechanical Engineering 201

Development of the body structure 0520F3-35.00.000 production process and the study of drilling strength characteristics

У кваліфікаційній роботі розроблено технологію виготовлення технології деталі корпус 0520Ф3-35.00.000 з дослідженням силових характеристик процесу свердління. Прийняті в кваліфікаційній роботі інженерні рішення дали змогу підвищити якість виготовлення деталі і зменшити підготовчо-заключний час на операціях, забезпечили концентрацію операцій а також скорочення затрат на виготовлення деталі. Для забезпечення безпечних умов роботи персоналу розроблено питання охорони праці і безпеки у надзвичайних ситуаціях. Наведено теоретичне узагальнення і вирішення наукової задачі, що полягає в дослідженні силових характеристик процесу свердління.In qualification work the technology of manufacturing of technology of details of the case 0520Ф3-35.00.000 with research of power characteristics of process of drilling is developed. The engineering decisions made in the qualification work made it possible to improve the quality of part manufacturing and reduce the preparatory and final time for operations, ensure the concentration of operations and reduce the cost of manufacturing parts. To ensure safe working conditions for staff, issues of labor protection and safety in emergencies have been developed. Theoretical generalization and the decision of a scientific problem consisting in research of power characteristics of process of drilling are resulted.Вступ 1 Аналітична частина 1.1. Аналіз стану питання 1.2. Службове призначення деталі 1.3. Висновки та постановка задач 2 Науково-дослідна частина 2.1 Характеристика об’єкту або предмету дослідження 2.2. Оброблення результатів досліджень 2.3. Висновки 3 Технологічно-конструкторська частина 3.1. Аналіз технологічності деталі 3.2. Вибір способу одержання заготовки 3.3. Формування технологічного процесу 3.4. Визначення припусків на оброблення 3.5. Визначення режимів різання 3.6. Розрахунок пристосування 4. Проектна частина 4.1. Визначення основних і допоміжних площ цеху 4.2. Розробка планів компонування цеху та розміщення обладнання на дільниці 5. Охорона праці та безпека в надзвичайних ситуаціях 5.1 Розрахунок захисного заземлення горизонтально-розточувального верстата моделі 2620 5.2 Характеристика стихійних лих, аварій (катастроф) та їх наслідки Висновки Перелік посилань Додатк

Discrete modeling of sculptured surface machining for robust automatic feedrate selection

Traditional feedrate selection techniques currently used in three and five-axis CNC machining reduces milling efficiency. Manually estimated feedrates tend to be conservative and constant, greatly increasing mill time. The goal of this research is to develop robust techniques and software tools for automatically generating optimized feedrates for use on three and five-axis CNC mills, to both simplify the feed selection process and to increase the safety and efficiency of the milling operation through milling process simulation. The simulation software estimates milling force vectors for each tool move, and identifies a feedrate that maintains a desired peak force. The desired cutting force value may be selected to prevent cutter breakage, maintain part tolerance, or meet some other criteria. Other conditions are also considered, such as maximum allowable chip thickness and machine constraints. This allows for the generation of variable feedrates that are optimized for each tool move. The software consists of three distinct portions: a discrete mechanistic model, a discrete geometric model, and a CNC machine model. The mechanistic model estimates cutting forces as a function of cut geometry, cutter/stock relative velocity, and material constants. The geometric model keeps track of the changing in-process stock geometry and provides the cut geometry parameters required by the mechanistic model. The CNC machine model calculates the cutter/stock relative velocity based on feed inputs, machine kinematics, and controller behavior. A feed value is calculated in an iterative manner for each tool move based on the force estimates. The results of this research have produced accurate force estimates during sculptured surface machining, and have also demonstrated that this approach at automatic feedrate selection is feasible. Testing of feedrate selection has included the five-axis milling of production turbomachinery in an industrial environment. An average improvement in efficiency of 20% has resulted from the use of the optimized feeds

ReSCon '12, Research Student Conference: Book of Abstracts

The fifth SED Research Student Conference (ReSCon2012) was hosted over three days, 18-20 June 2012, in the Hamilton Centre at Brunel University. The conference consisted of 130 oral and 70 poster presentations, based on the high quality and diverse research being conducted within the School of Engineering and Design by postgraduate research students. The conference is held annually, and ReSCon plays a key role in contributing to research and innovations within the School