Made available in DSpace on 2014-06-11T19:22:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-03-25Bitstream added on 2014-06-13T18:49:35Z : No. of bitstreams: 1 000740375.pdf: 2082789 bytes, checksum: d1483f48718c198c624d0f146dae6d70 (MD5) / Os problemas de corte ótimo são considerados como clássicos dentro da pesquisa operacional, dado sua grande área de aplicação na industria e sua alta complexidade matemática e computacional. Um dos problemas mais conhecidos desta classe é o chamado Cutting Stock Problem, o qual permite dividir uma placa em varias peças de diversos tamanhos, com a finalidade de obter a configuração que maximize a área da placa que está sendo utilizada. Dado o nível de dificuldade e a grande quantidade de aplicações deste problemas em diversas áreas, existe muito interesse em criar novos procedimentos eficientes para resolver este tipo de problemas. Nesta dissertação, é apresentado o estado da arte dos diversos problemas de corte bidimensional de peças retangulares em uma única placa, em varias placas e em rolos, considerando a possibilidade de rotacionar as peças em um ângulo de 90 e com restrições de corte tipo não-guilhotinado. Além disso, são descritas as abordagens matemáticas aplicadas pelos diversos pesquisadores dedicados a resolver estes problemas. Este trabalho está focado em resolver exclusivamente o Cutting Stock Problem com e sem rotação de peças. Portanto, é proposto um tipo de codificação binária com vista a ser aplicada neste tipo de problema e resolvê-lo mediante o uso do algoritmo heurístico Bottom-Left, em conjunto com a metaheurística Simulated Annealing. Finalmente, para comprovar a eficiência da metodologia apresentada, foram utilizados alguns casos de estudo da literatura especializada, com diferentes níveis de complexidade. Para cada caso, são apresentados os resultados obtidos e é realizada uma comparação dos métodos de solução propostos para resolver o Cutting Stock Problem com e sem rotação de peças. / The problems of optimal cutting are considered as classic within the operational research, given their large area of application in industry and their high computational and mathematic complexity. One of the most well-known of this kind of problem is called the Cutting Stock Problem, which allows to divide a plate in several pieces of various sizes, in order to obtain the configuration that maximizes the area of the plate being used. Given the level of difficulty and the large number of applications of this problem in several areas, there is interest in creating new efficient procedures for solving this kind of problem. In this dissertation, it is presented the state of the art of the two-dimensional cutting problems of rectangular pieces on a single plate, in several plates and rollers, considering the possibility of rotating the pieces at an angle of 90 in which the cuts are restricted to non-guillotined type. Furthermore, the mathematical approaches applied by different researchers dedicated to solving these problems are described. This work is focused exclusively on solving the Cutting Stock Problem with and without rotating pieces. Therefore, a kind of binary encoding in order to be applied to this kind of problem and to solving it through the use of the Bottom-Left heuristic algorithm in conjunction with Simulated Annealing are proposed. Finally, to prove the efficiency of the presented methodology, some study cases from the specialized literature were used, with different levels of complexity. For each case, the results are presented and a comparison of the proposed solution methods for solving the Cutting Stock Problem with and without rotating pieces is performed.

Orientador: Peter Christian Hackspacher / Coorientador: Eduardo Augusto Campos Curvo / Banca: Julio Cesar Hadler Neto / Banca: Sandro Guedes de Oliveira / Resumo: No presente trabalho foram efetuados estudos sobre o annealing dos traços de fissão em epídoto. Os experimentos foram feitos aquecendo-se o mineral por tempos de 1, 10 e 100 horas, variando a temperatura de 350 a 950°C. Os resultados obtidos foram curvas de annealing tanto para comprimento como para densidade dos traços. Os dados de comprimento dos traços de fissão foram utilizados para obter os parâmetros do modelo de cinética de annealing para o epídoto. O modelo utilizado foi o proposto pelo grupo de Cronologia da UNICAMP. Cálculos baseados nesses ajustes conduziram a uma previsão de zona de annealing parcial (ZAP) entre 218 a 588°C (para 1 Ma). Quando unidos com os dados de annealing para epídoto de Curvo (2005) a zona de annealing parcial prevista varia de 218 a 487°C (para 1 Ma). Esses valores situam a ZAP para tracos de fissão armazenados no epídoto acima da ZAP para a apatita e sobreposta a ZAP do zircão (possuindo, contudo o limite superior da ZAP acima da do zircão). Uma nova curva de ataque químico foi confeccionada com intenção de se utilizar uma menor temperatura do reagente (15°C, 40% HF). Nove pontos de ataque químico foram realizados, em tempos que variam de 30 a 110 minutos. O tempo estabelecido como ótimo foi 80 minutos. Realizou-se também, uma tentativa de datação de uma amostra de fratura localizada nas redondezas do município de Curitiba. A idade aparente encontra da foi de 240±209 Ma / Abstract: This paper presents studies conducted on the annealing of fission tracks in the epidote. The experiments were done by heating the mineral in time periods of 1, 10 and 100 hours, varying the temperature between 350 and 950°C.The results obtained were annealing curves both for length and for density of the fission tracks. The length data of the fission tracks were used to obtain the parameters for the annealing kinetics model of the epidote. The kinetic model for fission track used was the one proposed by the UNICAMP Chronology group. The mathematical calculations based on these adjustments led to a prediction of a partial annealing zone (PAZ) between 218 and 588°C (for 1 Ma).When united with the data for epidote annealing from Curvo (2005) the partial annealing zone varies from 218 to 487°C (for 1 Ma).These values situate the epidote PAZ above the apatite PAZ and having an intersection with the zircon one (presenting however an upper limit superior to the zircon PAZ).A new etching curve was measured aiming at a lower reagent temperature (15°C, 40% HF). Nine etching points were carried out in time periods ranging from 30 to 110 minutes. The optimal etching time was 80 minutes. An attempt to date an epidote fracture sample located near the city of Curitiba was also conducted. The dating provided the apparent age of 240±209 Ma / Mestre

No description available.

I investigate use of the simulated annealing heuristic to seek phylogenetic trees judged optimal according to the principle of parsimony. I begin by looking into the central data structure in phylogenetic research, the tree. I discuss why it is usually necessary to employ a heuristic, rather than an exact method, when seeking parsimonious trees. I summarise different heuristic approaches. I explain how to use the program LVB, written to use simulated annealing in the search for parsimonious trees. I use LVB, with different combinations of values for parameters controlling the annealing search, to re-analyse two DNA sequence data matrices, one of 50 objects and one of 365 objects. Equations to estimate suitable control parameters, on the basis of desired run time and quality of result, are fitted to data obtained by these analyses. Future directions of research are discussed.

Industrial utilization of polymeric gas separation membranes is predicted to increase significantly over the next 20 years. This growth will be driven by application of membrane based separations to increasingly aggressive feed streams. In this work, the performance of defect-free Matrimid asymmetric hollow fiber membranes in the presence of high pressure carbon dioxide and trace levels of toluene and n-heptane in the feed stream are studied. Specifically, this work shows a significant decrease in the carbon dioxide plasticization pressure and the carbon dioxide permeance prior to plasticization as a result of accelerated physical aging at ambient temperature. Interestingly, sub-Tg thermal annealing at 220 oC reverses the effects of physical aging by increasing the plasticization pressure and the carbon dioxide permeance prior to plasticization for a typical polyimide commonly used in membranes. The performance of Matrimid asymmetric hollow fiber membranes in feed streams contaminated with up to 1200 ppm toluene and 2000 ppm n-heptane is investigated. In the presence of both feed stream contaminants, the productivity and efficiency of the membrane are observed to significantly decrease in this work. These decreases in performance are shown to be the result of antiplasticization, and a free volume based model is developed to correlate the effect of feed stream contamination on membrane performance

The present study aims at studying the surface morphology, crystallinity and optical emission property of Mg added ZnO grown by molecular beam epitaxy. Zn1-xMgxO epitaxial films were first grown at a fixed Zn flux of 1¡Ñ10-7 mbar and Mg flux of 4¡Ñ10-10 to 6.2¡Ñ10-9 mbar on sapphire substrates at 400 oC. The corresponding Mg content (x) is in a range of <0.01 to 0.17. Scanning electron microscopy observations indicated that the surface of the films are flat. The orientation relationship between the film and the substrate is: (0001)Zn1-xMgxO¡ü(0001)Al2O3©M[101 ¡Â0] Zn1-xMgxO¡ü[112 ¡Â0] Al2O3. The full width at half maximum (FWHM) of the (0002) reflection in rocking curve measurement is in a range of 3.83 o to 4.81 o. Photoluminescence results showed that the intensities of both the near band-gap emission and the deep level emission increases with increasing Mg content. The former has FWHM values of 0.16-0.21 eV. While the epitaxial films were grown at a high Zn flux of 5¡Ñ10-7 mbar and Mg flux of 2¡Ñ10-9 to 9.6¡Ñ10-9 mbar on sapphire and LiAlO2 substrates at 400 oC, the film surface are at high roughness. The FWHM of (0002) rocking curve is 4.43 o to 5.71 o for films grown on sapphire and is relatively larger of 6.88 o to 8.18 o for films grown on LiAlO2, respectively. These films possess a stronger near band-gap emission and a lower deep level emission as compared to the films grown at a low Zn flux. After annealed at 600 oC in oxygen or nitrogen, the FWHMs of the (0002) rocking curve for most of the epilayers decreased slightly. The photoluminescence results were rather distinct. For samples having low Mg content (x<0.05), the intensity of the near band-gap emission increases 50-200 ¢H after annealed in oxygen. The intensity of the near band-gap emission did not change but that of the deep level emission decreases ~50 ¢H for the film having x=0.16 after annealing in oxygen. The emission characteristics basically do not change after annealed in nitrogen.

Twin induced plasticity (TWIP) steel is a new type of structural steel, which is characterized by both high strength and superior ductility. The key to twin formation lies in the control of the stacking fault energy (SFE) of the alloy. In this thesis, the effect of heat treatment on the tensile property and microstructure of a Fe-10Mn-3Al-0.6C alloy was studied. After annealing at 675¢J for different times, It was found that both austenite and ferrite phases existed. The volume fraction and composition of these two phases did not change significantly by the heat treatment conditions used. When annealed at 675¢J, increasing annealing time caused the carbides formed at grain boundaries gradually dissolved, and led to the higher ultimate tensile stress, 900MPa, and elongation, 40%. Deformation twins were formed in the austenite phase after tensile test in the annealed specimens, indicating that TWIP behavior occurred. The best tensile property of Fe-10Mn-3Al-0.6C alloy obtained by annealing at 675¢J is within the target property of the 3rd AHSS.

The area of advanced gate dielectrics has gained considerable attention recently, and there are significant leakage current and reliability concerns for oxy-nitride in this regime. So it¡¦s an important business to use alternate high-k dielectrics instead of oxy-nitride. Titanium dieoxide shows a high dielectric constant for dielectric applications. Besides, strontium can create additional oxygen vacancies that can enhance dielectric constant. In this study, we prepared SrTiO3 film by liquid phase deposition which is a novel material considered to have high dielectric constant. From several characteristic measurements, we found that SrTiO3 with exhibiting higher dielectric constant and well interface state which is very promising candidates to instead of titanium dieoxide. The physical and chemical properties of SrTiO3 films by means of several measuring instruments, including Fourier transform infrared spectrometer (FTIR), secondary ion spectrometer (SIMS), and X-Ray diffractometer (XRD). An Al / SrTiO3 / Si metal-oxide-semiconductor (MOS) capacitor structure was used for the electrical measurements. To improve the electrical properties, we investigated the characteristics of SrTiO3 films after annealing in oxygen, nitrous oxide, and nitrogen ambient. Including the variations of thickness, structure, dielectric constant, and leakage current were discussed in this work.

In this thesis, we use reactive RF magnetron sputtering to deposit zinc oxide (ZnO) buffer layer and main layer on SiO2/Si substrate at room temperature. After various annealing treatments, the ZnO nanowires can be obtained. The effects of buffer layer on the crystallization of ZnO main layer and the zinc-to-oxygen ratio in the main layer on the growth of the ZnO nanowires are analyzed by PL, SEM, XRD and EDS. Finally, the growth mechanism of the ZnO nanowires is investigated by various annealing temperatures. According to the experimental results, surplus zinc in the main layer is necessary for the ZnO nanowires growth. When the annealing temperature is higher than the melting point of zinc, it will melt and be extruded onto thin film surface as a result of the thermal stress. As soon as the melting zinc on the film surface reacts with the oxygen in the air, ZnO nanowires can be obtained. The optimum ZnO nanowires which possess better morphology and high density are revealed by conventional thermal annealing at 600¢J for 90 minutes.

Recently, there has been increasing demands for high dielectric materials to replace SiO2 for high-density dynamic random access memories with ultralarge scale integration. TiO2 and BaTiO3 are very promising insulators for applications to DRAMs, as they exhibit higher dielectric constant.The growths of TiO2 and BaTiO3 thin films on (100) silicon are studied by MOCVD using Ti(i-OC3H7)4, Ba(DPM)2(tetraene)2 and N2O as precursors. The growth was performed in a cold wall horizontal system in the temperature range of 350~700¢J. The growth rates of TiO2 and BaTiO3 films are affected by the Ti flow rate, growth temperature and reactor pressure. The structures of TiO2 and BaTiO3 films are polycrystalline by X-ray diffraction examinations. The dielectric constant of as-grown TiO2 can reach 85 and BaTiO3 can reach 300 derived by C-V curves with the contact area 3.14¡Ñ10-4 cm2. In addition, the influences of postannealing treatment under an O2 and N2 ambient with different annealing temperature and time on the structural and electrical properties of as-grown TiO2 films will be also studied. However, TiO2 and BaTiO3 films have columnar structures acted the paths of leakage current. We use thermal annealing to reduce the leakage current. In the future, to enhance the dielectric constant and reduce the leakage current of the films is the goal in our study.