A tool path generation method for sculptured surfaces defined by triangular meshes is presented in this thesis along with an algorithm that helps determine the best type of cutter geometry to machine a specific surface. Existing tool path planning methods for sculptured surfaces defined by triangular meshes require extensive computer processing power and result in long processing times mainly since surface topology for triangular meshes is not provided. The method presented in this thesis avoids this problem by offsetting each triangular facet individually. The combination of all the individual offsets make up a cutter location surface. A single triangle offsetting results in many more triangles; many of these are redundant, increasing the time required for data handling in subsequent steps. To avoid the large number of triangles, the proposed method creates a bounding space to which the offset surface is limited. The original surface mesh describes the bounding surface of a solid, thus it is continuous with no gaps. Therefore, the resulting bounding spaces are also continuous and without gaps. Applying the boundary space limits the size of the offset surface resulting in a reduction in the number of triangular surfaces generated. The offset surface generation may result in unwanted intersecting triangles. The tool path planning strategy addresses this issue by applying hidden-surface removal algorithms. The cutter locations from the offset surface are obtained using the depth buffer. The simulation and machining results show that the tool paths generated by this process are correct. Furthermore, the time required to generate tool paths is less than the time required by other methods. The second part of this thesis presents a method for selecting an optimal cutter type. Extensive research has been carried out to determine the best cutter size for a given machining operation. However, cutter type selection has not been studied in-depth. This work presents a method for selecting the best cutter type based on the amount of material removed. By comparing the amount of material removed by two cutters at a given cutter location the best cutter can be selected. The results show that the optimal cutter is highly dependent on the surface geometry. For most complex surfaces it was found that a combination of cutters provides the best results.

Baigiamajame magistro darbe ištirtas ofsetinių dažų poveikis skirtingų popierių struktūrinėms, optinėms ir mechaninėms savybėms. Atliktas palyginimas tarp balto popieriaus, nepadengto dažų sluoksniu, su atspaudais, padengtais keturiais skirtingais dažų sluoksnio storiais. Nustatyta, kurie popieriai esant tam tikram dažų sluoksnio storiui turi mažiausią bei didžiausią atsparumą mechaninėms savybėms, blogiausias ir geriausias optines savybes. Eksperimentiškai ištirtos šešių popierių, ofsetinių atspaudų trinties savybės ir nustatyti statinės ir kinetinės trinties koeficientai. Nustatytos šių koeficientų vertės tarp popieriaus ir popieriaus, tarp popieriaus ir atspaudo ir tarp atspaudo ir atspaudo. Darbo apimtis – 67 teksto be priedų, 45 iliustracijos ir 2 lentelės. / The thesis investigated inks effects of the different papers structural, optical and mechanical properties. Performed comparison between the white paper, uncoated inks layer, with printed, coated in four different inks thickness. It was found which papers and with which kind of coated inks thickness have minimum and maximum resistance of mechanical properties, the best and the worst optical properties. Experimentally investigated six different papers and offset prints friction properties and determined the static and kinetic coefficients of friction. These coefficients determined between the paper and the paper, the paper and print, and the print and print. Space of works – 67 pages of text without additions, 45 figures, 2 tables.

With many unique advantages compared to traditional sensors, optical fiber sensors have been studied and applied to many different areas. Interferometric sensors are one of the most useful sensor types due to their high sensitivities and relatively relaxed requirement on the stability of the optical source’s power level. In-line optical interferometric sensors received further attention as a result of compactness and robustness to the reference channel instability. Long period gratings (LPG) are one of the most useful components in the in-line optical fiber sensors. However, the fabrication cost is normally high due to the expensive masks and stringent photolithographic procedures. Two new sensor components, namely abrupt tapers and connector-offset attenuators, are proposed as couplers in the optical fiber to couple light from core to cladding (or reverse) to replace LPGs. Using OPTIBPM software, the coupling coefficients between core and cladding modes are calculated. For an abrupt taper, coupling mostly happens between LP01 and LP0m modes; the first ten LP0m modes account for 98% of the incident mode energy. For a connector-offset attenuator, coupling mainly happens between LP01 and LP1m modes; the first ten LP0m and first ten LP1m modes account for 92% of the incident mode energy. The relative direction of two connector-offset attenuators is found to be very important to the interference performance. Phase dependent interference (attenuation range from 1 dB to 35 dB) is observed in the simulation for the interferometers using abrupt tapers and connector-offset attenuators. Three interferometers are realized in the experiment using the abrupt tapers (Mach-Zehnder and Michelson) or the connector-offset attenuators (Michelson). Due to the interference between core and cladding modes, transmission is strongly dependent on wavelength ranging from 3 dB to 26 dB in the best implementation. Although it is difficult to make two perfect parallel connector-offset attenuators required by the Mach-Zehnder interferometers by using the fusion splicer, some evidence of constructive interference is observed in the experiment. The interferometers are tested as refractive index (RI) sensors using the maximum attenuation wavelength shift relative to the RI change. Given that the minimum resolution of optical spectrum analyzer is 10 pm, ~10-4 difference of the RI can be detected by the interferometric sensors using the abrupt tapers or the connector-offset attenuators. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-08-18 15:42:59.506

This experimental study compares green printing technologies (ink and stock) to traditional printing technologies (ink and stock) regarding how they compare in quality. The quality was measured using the print characteristics of gray balance and dot gain. A comparison of the two independent variables (ink and stock) was conducted to determine if a difference exists for the selected characteristics. It has been suggested that the green technologies, despite being more environmentally friendly, are not as high in quality and therefore result in a lower quality printed piece. This research used a four-color test form that was printed using both the green and traditional technologies. The characteristics were measured using an X-rite 528 spectrodensitometer, after which the data were analyzed and conclusions reported. The results of the study suggest that there is no practical significance between the different inks and stocks employed in this study. It was determined however that the best print quality in terms of dot gain (meaning the least amount of dot gain) resulted from the combination of green technologies (ink and paper). / Department of Technology

Soft errors are radiation-induced ionization events (induced by energetic particles like alpha particles, cosmic neutron, etc.) that cause transient errors in integrated circuits. The circuit can always recover from such errors as the underlying semiconductor material is not damaged and hence, they are called soft errors. In nanometer technologies, the reduced node capacitance and supply voltage coupled with high packing density and lack of masking mechanisms are primarily responsible for the increased susceptibility of SRAMs towards soft errors. Coupled with these are the process variations (effective length, width, and threshold voltage), which are prominent in scaled-down technologies. Typically, SRAM constitutes up to 90% of the die in microprocessors and SoCs (System-on-Chip). Hence, the soft errors in SRAMs pose a potential threat to the reliable operation of the system. In this work, a soft-error-robust eight-transistor SRAM cell (8T) is proposed to establish a balance between low power consumption and soft error robustness. Using metrics like access time, leakage power, and sensitivity to single event transients (SET), the proposed approach is evaluated. For the purpose of analysis and comparisons the results of 8T cell are compared with a standard 6T SRAM cell and the state-of-the-art soft-error-robust SRAM cells. Based on simulation results in a 65-nm commercial CMOS process, the 8T cell demonstrates higher immunity to SETs along with smaller area and comparable leakage power. A 32-kb array of 8T cells was fabricated in silicon. After functional verification of the test chip, a radiation test was conducted to evaluate the soft error robustness. As SRAM cells are scaled aggressively to increase the overall packing density, the smaller transistors exhibit higher degrees of process variation and mismatch, leading to larger offset voltages. For SRAM sense amplifiers, higher offset voltages lead to an increased likelihood of an incorrect decision. To address this issue, a sense amplifier capable of cancelling the input offset voltage is presented. The simulated and measured results in 180-nm technology show that the sense amplifier is capable of detecting a 4 mV differential input signal under dc and transient conditions. The proposed sense amplifier, when compared with a conventional sense amplifier, has a similar die area and a greatly reduced offset voltage. Additionally, a dual-input sense amplifier architecture is proposed with corroborating silicon results to show that it requires smaller differential input to evaluate correctly.

Thesis (Ph. D.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 61-65).

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. / Made available in DSpace on 2012-10-22T19:04:27Z (GMT). No. of bitstreams: 1 226755.pdf: 3358154 bytes, checksum: 24d93c69d8b6413379b28f45eb0b2a8e (MD5) / Este trabalho tem como objetivo principal analisar a atividade dos operadores de máquinas offset da Imprensa Universitária da Universidade Federal de Santa Catarina. Apresenta um panorama geral das condições de trabalho desses trabalhadores, as respectivas sobrecargas posturais e as recomendações para a melhoria das condições laborais, no sentido de gerar uma melhor qualidade de vida no trabalho. Para tanto, foi escolhido como local da pesquisa a Imprensa Universitária da Universidade Federal de Santa Catarina, onde se disponibilizou o setor de impressão em offset para a sua realização. Participaram da pesquisa cinco operadores (servidores públicos) que trabalham regularmente com as respectivas máquinas. Para a coleta de informações e dados utilizou-se técnicas de entrevista, aplicação de um questionário, diagrama para percepção de desconforto postural, observação in loco, filmagens e registros fotográficos das atividades de trabalho. Para a análise das posturas foi utilizado o método OWAS com subseqüente tratamento dos dados com o programa computacional WinOWAS® (Tampere University of Technology) para verificação das posturas de trabalho e os respectivos riscos de constrangimentos músculo-esqueléticos. Essas posturas foram então categorizadas pelo método, enquadrando-se duas delas nas categorias 3 e 4, traduzindo riscos músculo-esqueléticos para todos os participantes deste estudo, cujo método de trabalho deverá ser mudado assim que possível (categoria 3) e medidas devem ser tomadas imediatamente para mudança postural (categoria 4). Os resultados apontaram para uma incidência de desconforto corporal devido às posturas adotadas durante as atividades laborais dos operadores das máquinas, com grande ênfase na região da coluna lombar, devido aos movimentos de maior manifestação apresentados: flexão, rotação e flexão lateral de tronco, combinados ou não. Chegou-se à conclusão que o trabalho do operador de máquina offset da Imprensa Universitária, é uma atividade de natureza repetitiva em ciclos, sempre na posição em pé, com considerável desconforto e sobrecarga postural. Nesse sentido, mudanças de natureza ergonômica seriam necessárias.

Carbon offsetting has been an institutionalised response to climate change for over a decade. Over this period, climate change has become more severe and calls for climate justice have become increasingly insistent. Yet the normative controversies of carbon offsetting remain unresolved, as debates about the environmental quality, development impacts and ethical implications of carbon offsetting continue. This thesis explores the relationship between morality and carbon offsetting in three domains. First it provides an evaluation of the ethics of offsetting. Second it gives an account of the 'lay normativity' of the market, describing how carbon market actors interpret and act upon issues of moral concern. And third, it explains offsetting's moral economy. First, the thesis examines the moral rationales for and problems of offsetting in order to clarify the bases of criticisms levelled at offsets by researchers concerned about trends in neoliberal environmental governance. In evaluation of the ethics of offsetting, the PhD recognises some limited rationales, but mainly highlights widespread problems including lack of environmental integrity and failure to produce 'sustainable development'. The structure of the market is shown to create opportunities for malpractice and difficulties for reform. Second, building on work in cultural political economy, the research describes carbon offsetting's lay normativity. The account is based on interviews with over sixty carbon offset market actors including project developers, consultants, auditors, regulators, retailers and buyers in the UK, continental Europe, and in India. Findings show that the market is founded on ethical principles: offsetting is nothing without notions of environmental and developmental care. Critiques of, and reforms to, offsetting are also grounded in principled debate. But carbon market actors often use their power to further commercial interests that are not aligned with production of environmental or developmental value. And yet, even as rationales are ignored and problems are amplified, market actors maintain a discursive semblance of moral behaviour through forms of justification, story-telling and identity work. Third, the thesis explains how principles, profit and power combine to affect the governance of offsetting. It shows that the concentration of power among profit-seeking actors drives the production of offsetting's moral problems in the stages of project development, regulation and retail. Commercial interests in the politics of knowledge lead to manipulation of the discursive framings through which people come to understand offsets. Ethical narratives are deployed to sustain the market in states of dysfunction, enabling privileged groups to gain exchange value at the expense of climate protection and sustainable development. Through this explanatory work, the PhD contributes an original application of ideas about moral political economy to the case of climate change and carbon trading, demonstrating that powerful actors can shape culture and alter our perceptions of right and wrong.

Although nonlinear model predictive control (NMPC) might be the best choice for a nonlinear plant, it is still not widely used. This is mainly due to the computational burden associated with solving online a set of nonlinear differential equations and a nonlinear dynamic optimization problem in real time. This thesis is concerned with strategies aimed at reducing the computational burden involved in different stages of the NMPC such as optimization problem, state estimation, and nonlinear model identification. A major part of the computational burden comes from function and derivative evaluations required in different parts of the NMPC algorithm. In this work, the problem is tackled using a recently introduced efficient tool, the automatic differentiation (AD). Using the AD tool, a function is evaluated together with all its partial derivative from the code defining the function with machine accuracy. A new NMPC algorithm based on nonlinear least square optimization is proposed. In a first–order method, the sensitivity equations are integrated using a linear formula while the AD tool is applied to get their values accurately. For higher order approximations, more terms of the Taylor expansion are used in the integration for which the AD is effectively used. As a result, the gradient of the cost function against control moves is accurately obtained so that the online nonlinear optimization can be efficiently solved. In many real control cases, the states are not measured and have to be estimated for each instance when a solution of the model equations is needed. A nonlinear extended version of the Kalman filter (EKF) is added to the NMPC algorithm for this purpose. The AD tool is used to calculate the required derivatives in the local linearization step of the filter automatically and accurately. Offset is another problem faced in NMPC. A new nonlinear integration is devised for this case to eliminate the offset from the output response. In this method, an integrated disturbance model is added to the process model input or output to correct the plant/model mismatch. The time response of the controller is also improved as a by–product. The proposed NMPC algorithm has been applied to an evaporation process and a two continuous stirred tank reactor (two–CSTR) process with satisfactory results to cope with large setpoint changes, unmeasured severe disturbances, and process/model mismatches. When the process equations are not known (black–box) or when these are too complicated to be used in the controller, modelling is needed to create an internal model for the controller. In this thesis, a continuous time recurrent neural network (CTRNN) in a state–space form is developed to be used in NMPC context. An efficient training algorithm for the proposed network is developed using AD tool. By automatically generating Taylor coefficients, the algorithm not only solves the differentiation equations of the network but also produces the sensitivity for the training problem. The same approach is also used to solve online the optimization problem of the NMPC. The proposed CTRNN and the predictive controller were tested on an evaporator and two–CSTR case studies. A comparison with other approaches shows that the new algorithm can considerably reduce network training time and improve solution accuracy. For a third case study, the ALSTOM gasifier, a NMPC via linearization algorithm is implemented to control the system. In this work a nonlinear state–space class Wiener model is used to identify the black–box model of the gasifier. A linear model of the plant at zero–load is adopted as a base model for prediction. Then, a feedforward neural network is created as the static gain for a particular output channel, fuel gas pressure, to compensate its strong nonlinear behavior observed in open–loop simulations. By linearizing the neural network at each sampling time, the static nonlinear gain provides certain adaptation to the linear base model. The AD tool is used here to linearize the neural network efficiently. Noticeable performance improvement is observed when compared with pure linear MPC. The controller was able to pass all tests specified in the benchmark problem at all load conditions.