Dissertations / Theses on the topic 'Octets'
To see the other types of publications on this topic, follow the link: Octets.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Octets.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Dong, Kui. "Cess : (after Turandot) : for eight voices, eleven musicians and tape /." May be available electronically:, 1997. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Full text
2
Gotō, Yo. "Voci lontani for flute, trumpet, percussion, piano, and string quartet, critical essay and score /." connect to online resource. Access restricted to the University of North Texas campus, 2004. http://www.unt.edu/etd/all/Aug2004/goto%5Fyo/index.htm.
Full text
3
Bolles, Marita. "What exit /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3049669.
Full text
4
Dimoff, Trevor Anthony. "The third impossible thing before breakfast, an octet for saxophone and string quartets." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0013/MQ34935.pdf.
Full text
5
May, Andrew Emerson Ralph Waldo. "Vanishing : a composition for ensemble and computer /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p9984809.
Full textAbstract:
Thesis (Ph. D.--Music)--University of California, San Diego.Vita. For flute (piccolo), piano, percussion (1 performer), 2 violas, 2 violoncellos, and computer. Includes technical notes and instructions for performance preceding score.
6
Thorvaldsdottir, Anna S. Thorvaldsdottir Anna S. Thorvaldsdottir Anna S. Thorvaldsdottir Anna S. "Music and ideas." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p1453657.
Full textAbstract:
Thesis (M.A.)--University of California, San Diego, 2008.Accompanying disc contains sound files of recordings of the musical compositions. The 1st work for 13 instruments; 2nd for 2 oboes, 2 clarinets, 2 bassoons, and 2 horns; 3rd for voice, 6 stethoscopes, and computer which manipulates sounds picked up by the stethoscopes. Title from first page of PDF file (viewed July 11, 2008). Available via ProQuest Digital Dissertations. Includes bibliographical references: P. 137.
7
Wise, Scott L. "Octet for Winds." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1368025151.
Full text
8
Linhart, Melodie E. "Synaesthetics : for violoncello & octet /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/11306.
Full textAbstract:
Thesis (Ph. D.)--University of Washington, 2006.For solo violoncello and octet comprised of piccolo, English horn, clarinet in E♭, contrabassoon, horn in F, tuba, xylophone, and contrbass. Vita. Includes bibliographical references (p. 147).
9
Norton, Benjamin D. "Little Eichmanns: A Composition for Chamber Octet." UKnowledge, 2013. http://uknowledge.uky.edu/music_etds/18.
Full textAbstract:
An original composition in one movement for a chamber octet comprised of a string quartet and a jazz piano quartet with tenor saxophone. The work develops an idée fixe, introduced in the opening bars, through a wide variety of transformations, textures, and styles. The two quartets begin in antiphonal alteration, united in thematic material, yet separated by style. A modern art music style contrasts with an improvisational jazz style. Gradually, the two quartets, and their concomitant musics, bleed into one another, breaking down stylistic boundaries. In the conclusion of the work, the idée fixe, the supplementary themes, and the two quartets coalesce into an organic sonic whole.
10
Liu, Jiayi. "Display of octrees." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ32491.pdf.
Full text
11
Jonker, Jano. "Octet and decuplet baryon masses at finite temperature." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/17518.
Full textAbstract:
Includes bibliography.Octet and decuplet baryon masses are studied at finite temperature in the framework of finite energy QCD sum rules. In all cases it is found that the mass stays fairly constant over a range of temperatures, increasing sharply near the critical temperature for deconfinement Tc.
12
Cooke, Ashley Noel. "Lattice QCD study of octet hyperon semi-leptonic decays." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9647.
Full textAbstract:
We present a calculation of vector and axial-vector form factors for each of the octet hyperon semi-leptonic transition matrix elements by using the techniques of lattice QCD where simulations were performed with Nf = 2 + 1 flavours of dynamical O(a)-improved Wilson fermions. We also study the electromagnetic form factors, axial charges and other properties of octet baryons. Errors due to extrapolation to zero transferred momentum are reduced by applying a twist to the boundary conditions on the lattice. Our form factor results compare favourably with experiment and other lattice QCD determinations. By considering an expansion about the SU(3)-flavour symmetric limit we seek to investigate and quantify the symmetry breaking effects in these matrix elements due to the mass splitting between the strange and light quarks. We find good agreement with the Ademollo-Gatto theorem for the vector form factor, a measurable amount of breaking in the axial-vector form factor and significant effects in the weak magnetism form factor. Knowledge of the parameterisation of SU(3)-flavour symmetry breaking allows for a series of constrained fits to be made to the form factor results which are used to arrive at a 'baryonic' estimation of the Cabibbo-Kobayashi-Maskawa matrix element |Vus|.
13
Pavlova, Mariela. "Vérification de programmes en code octet et ses applications." Nice, 2007. http://www.theses.fr/2007NICE4010.
Full textAbstract:
Les techniques de vérification basées sur les logiques de programmation ainsi que sur les générateurs de conditions de vérification permettent de raisonner de manière efficace sur les programmes. Bien que ces techniques aient souvent été utilisées avec des langages de haut niveau pour bénéficier de leurs structures, il est souvent nécessaire, plus spécifiquement dans le contexte du code mobile, de prouver la correction de programmes déjà compilés. C’est pourquoi il est très intéressant d’avoir un moyen pour utiliser la vérification de code source au niveau de l’utilisateur de code. Nous proposons un mécanisme qui permet de transférer des informations depuis le programme source vers le programme compilé. Il est construit autour d’un langage de spécification pour le code binaire, un générateur de conditions de vérification qui s’utilise sur des programmes annotés et un compilateur qui transforme les annotations au niveau du code source en des annotations au niveau du code binaire. Nous montrons que le générateur des conditions de vérification est correct et que les obligations de preuves au niveau du source et du code binaire sont presque les mêmes. Nous illustrons les bénéfices de notre démarche par deux études de casProgram verification techniques based on programming logics and verification condition generators provide a powerful means to reason about programs. Whereas these techniques have very often been employed in the context of high-level languages in order to benefit from their structural nature. It is often required, especially in the context of mobile code, to prove the correctness of compiled programs. Thus it is highly desirable to have a means of bringing the benefits of source code verification to code consumers. We propose a mechanism that allows to transfer evidence from source programs to compiled programs. It builds upon a specification language for bytecode, a verification condition generator that operates on annotated programs, and a compiler that transforms source annotations into bytecode annotations. We show that the verification condition generator is sound, and that the proof bytecode level nearly coincides. We illustrate the benefits of oue framework in two case studies
14
Behnen, Severin Hilar Behnen Severin Hilar Behnen Severin Hilar Behnen Severin Hilar Behnen Severin Hilar Behnen Severin Hilar Behnen Severin Hilar Behnen Severin Hilar. "Volume I. The construction of motion graphics scores Volume II. Seven motion graphics scores /." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1581435611&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Full textAbstract:
Thesis (Ph. D.)--University of California, Los Angeles, 2008.CD-ROM entitled "The motion graphics scores of Severin Behnen" includes the animated scores. Includes bibliographical references (v. 1, leaves 138-142).
15
Silva, J?lio C?sar Oliveira da. "Problemas de aprendizagem sobre liga??es qu?micas para estudantes de gradua??o." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17672.
Full textAbstract:
Made available in DSpace on 2014-12-17T15:42:00Z (GMT). No. of bitstreams: 1
JulioCOS_DISSERT.pdf: 1559177 bytes, checksum: 5d76456c4b64130c51ab0adec9c84e15 (MD5)
Previous issue date: 2010-08-16This research aims at identifying the learning problems in newly undergraduate students at university, interpreting the nature and causes of these problems, offering subsidies to overcome these difficulties and enabling a meaningful learning through which students give meaning to their learning. As an object for this work was chosen the theme Chemical Bonds - where were studied the forces between atoms to form molecules, compound ions and ionic crystalline structures - and is characterized as one of the most important subjects of Chemistry. In research, it was used a questionnaire with five open questions, answered by 147 students from the early periods of degrees in Chemistry at Universidade Federal do f Rio Grande do Norte. The answers revealed uncertainty on the part of students, both conceptual and representation, with superficial justifications, always using the octet rule to describe models of chemical bonds. Results suggest that these students had inadequate training in high school and that the examinations for entrance into the ranks were made according to flexible criteria less demanding in terms of knowledge. These observations have led to the conclusion that for future changes, it is necessary for high schools and in the early periods in universities favoring the adoption of pedagogical approaches in context and applying strategies to overcome the teaching of superficial memorization on Chemical Bonds, which probably have applied to the teaching of other subjects of chemistry
Este trabalho teve o objetivo de identificar problemas de aprendizagem em alunos de gradua??o rec?m ingressante na universidade, interpretar a natureza e as causas desses problemas, oferecendo subs?dios para supera??o de tais dificuldades e possibilitando uma aprendizagem significava atrav?s da qual o aluno atribua sentido em seu aprendizado. Para o desenvolvimento desse trabalho foi escolhido o tema Liga??es Qu?micas - onde se estudam as for?as que agem entre os ?tomos para formar mol?culas, ?ons compostos ou estruturas cristalinas i?nicas -, que se caracteriza como um dos mais importantes assuntos da Qu?mica. Para isso, utilizou-se um question?rio com cinco perguntas abertas, respondidas por 147 estudantes dos per?odos iniciais das gradua??es em Qu?mica da Universidade Federal do Rio Grande do Norte. As respostas obtidas revelaram inseguran?a dos estudantes, tanto em termos conceituais quanto de representa??o, com justificativas superficiais, recorrendo sempre ? regra do octeto para descrever modelos de liga??es qu?micas. Os resultados sugerem que esses estudantes tiveram uma forma??o inadequada, no ensino m?dio e que os exames para ingresso nas gradua??es se fizeram segundo crit?rios pouco exigentes em termos de conhecimentos. As observa??es feitas levam ? conclus?o de que, para mudan?as futuras, ? necess?rio que escolas de ensino m?dio e dos per?odos iniciais nas universidades privilegiem a ado??o de m?todos pedag?gicos contextualizados, aplicando estrat?gias para superar o ensino memor?stico e superficial sobre Liga??es Qu?micas, o que, provavelmente, se aplica ao ensino de outros temas da Qu?mica
16
Verdú, Blasco Pau. "Filamentos elásticos de elastolefina de alta durabilidad obtenidos a partir de copolímeros de bloque de etileno-octeno de baja densidad mediante la tecnología de polimerización por transferencia de cadena para aplicaciones en indumentaria de uso profesional." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/84166.
Full textAbstract:
En la actualidad el mercado carece de prendas elásticas para uso
profesional puesto que los elastanos habitualmente utilizados son
inestables frente a altas temperaturas y químicos agresivos, e.g.
termofijado, mantenimiento de indumentaria industrial etc.
Recientemente se han venido utilizado filamentos olefínicos
obtenidos a partir de copolímeros al azar de etileno-octeno (Dow
XLA™ fibers producidos por The Dow Chemical Company). Aunque más
resistentes a las temperaturas debido a la reticulación, su bajo
punto de fusión, alrededor de 50ºC, limita el comportamiento
elástico en tejidos pesados y tupidos para indumentaria
profesional.
La investigación tiene por objeto la obtención de monofilamentos
elásticos a partir copolímeros de bloque de etileno-octeno (cuyo
punto de fusión es más elevado) y con éstos, tejidos para
indumentaria profesional que ofrezcan mayor fuerza de
encogimiento a las temperaturas típicas de los pre-tratamientos,
tintura y acabado (50ºC-120ºC). El objetivo es hacer que los
tejidos encojan más durante las operaciones en húmedo bajo
temperatura para mejorar así su elasticidad y aumentar el peso en
comparación con los tejidos actuales manufacturados con los
convencionales copolímeros homogéneos de etileno-octeno
reticulados
Los tejidos deberán garantizar las siguientes propiedades durante
todo su ciclo de vida: estabilidad dimensional, relación
elasticidad-crecimiento mejorado, resistencia química,
resistencia térmica, durabilidad ante los lavados industriales y
un mejor confort termofisiológico y sensorial.Due to the lack of stability of elastane based materials against high temperatures and harsh chemicals, e.g. thermofixation and professional wear maintenance, elastic garments with elastane content are not yet fully commercial products. The Dow Chemical Company has recently commercialized a random ethylene-octene copolymer based fiber named Dow XLA™ fiber. Despite its higher temperature resistance as one of the crosslinking effects, its very low melting point, around 50ºC, establishes some limitations in elasticity such in heavy weight and high densely woven fabric cases typically found in professional wear applications. The target for the investigation is to produce block ethyleneoctene copolymer based filaments in which the melting point is supposed to be higher than in random copolymer materials. Different workwear fabrics will be manufactured with yarns containing such elastic filaments. It is supposed these fabrics to show high shrinkage forces even at dyeing and finishing temperatures, (50ºC-120ºC). The goal is to produce fabrics with superior shrinkage performance in order to achieve an excellent elastic power and the final desired fabric weight. Properties such as dimensional stability, stretch and growth ratio, temperature and chemical resistance and durability against industrial laundering should not be affected by the passage of the time. To validate this point these properties will be measured in the fabrics off loom and after the garment cycle life. These fabrics are also supposed to show better thermophysiological and sensorial properties than random copolymer fiber based textiles
17
Szram, Aleksander Jozef. "Interpreting the Octet '61 by Cornelius Cardew on the piano." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31169.
Full textAbstract:
This thesis investigates the performer's options in approaching the interpretation of the Octet '61 (1961) by Cornelius Cardew (1936-1981) as a solo piano performance. The Octet '61 is an indeterminate composition for any instrument(s) written using graphic notation. The score comprises sixty symbols and a set of performance instructions. The focus on a solo piano performance is justified for several reasons. It was published together with the February Pieces (1959-1961) for piano, the performance instructions by Cardew include several examples for a solo piano interpretation, and Cardew also composed a determinate version of the piece for solo piano, published as the Winter Potato No.1 (1961.) The thesis places the Octet '61 in the context of Cardew's indeterminate works, such as the February Pieces, Memories of You (1964) and Treatise (1963-1967), and compares it to works by other composers employing chance operations, specifically Music of Changes by Cage, Piano Sonata No.3 by Boulez and Klavierstück XI by Stockhausen. The content of the symbols and performing instructions is examined, and the testimony of Cardew interpreters John Tilbury, John White, David Bedford and Sam Richards is discussed. The content of the Winter Potato No.1 is compared to the Octet '61 symbols, and its relevance to the interpretation of the Octet '61 is gauged. The thesis contends that the Winter Potato No.1 is valuable as a demonstration of Cardew's contemporaneous interpretation of the symbols, but that it should not be used as a guide by other performers of the Octet '61. The Octet '61 was designed to take on a different form with each interpretation, and the use of the Winter Potato No.1 as a template would compromise this intention. The final chapter speculates as to why the Octet '61 is seldom performed at the turn of the 21st Century.Arts, Faculty of
Music, School of
Graduate
18
Renteria, Lisa M. "The Bassoon's Essential Role in the Evolution of the Wind Octet: The Serenade in Eb Major K. 375 by Mozart and the Octet for Winds by Stravinsky." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194443.
Full textAbstract:
The purpose of this study is in one part to observe the evolution of the wind octet genre and another to research the evolution of the bassoon's role in this ensemble. Specifically the essential role of the two bassoons are revealed by showing that they are the only pair of instruments that remain intact in the wind octet ensemble from the time of Mozart to the time of Stravinsky. Because of this, they provide the wind octet it's characteristic sound. To illustrate these points, two significant wind octets were examined in detail: The Serenade in Eb, K. 375 (1782) by Mozart and the Octet for Winds (1923/revised 1952) by Stravinsky. Despite the long time span between these two works, and the obvious changes in instrumentation, the Octet for Winds by Stravinsky could be called an evolved version of the earlier traditional wind octet. The research within illustrates how the writing for the bassoons changed and stayed the same as related to range, articulation, technical demands, interaction and blending, idiomatic features and role between the years of 1782 and 1923. Other octets that fall between these dates were examined to demonstrate this evolution. Also, in order to have a better understanding of the Serenade by Mozart and Octet for winds by Stravinsky, their symphonic works were analyzed to determine how each composer wrote for the bassoon in other genres and this is compared to the use of the bassoon in their octets.
19
Silva, António. "Form factors of the baryon octet in the chiral quark soliton model." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972728074.
Full text
20
Zola, Wagner Machado Nunan 1961. "Parallel gpu algorithms for compressed implicit octrees." reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/45749.
Full textAbstract:
Orientador : Prof. Dr. Luis Carlos Erpen de BonaTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 10/09/2015
Inclui referências : f. 97-101
Resumo: O algoritmo Barnes-Hut é um método aproximado amplamente usado para na simulação gravitacional de N-Corpos, que envolve a construção e eaminliamento de árvores esparsas a cada passo de simulação e assim reduzindo a complexidade computacional e possibilitando a solução de problemas práticos de grande escala, A natureza irregular desse código de eaminliamento em árvore apresenta desafios interessantes na sua computação em sistemas paralelos. Desafios adicionais ocorrem nesse tipo de padrão de computação paralela quando se deseja utilizar de maneira eficaz a capacidade computacional de arquiteturas de GPUs (processadores gráficos multieore de propósito geral), Oetrees são estruturas de dados que representam de maneira eficiente as informações de dados espaciais em várias áreas tais como computação científica, computação gráfica, processamento de imagens, dentre outras. Nosso enfoque nesse trabalho é de tratar explicitamente os padrões dinâmicos irregulares de acesso a dados em memória com o remapeamento de dados e transformações de lavouts, dependendo das estruturas acessadas. Também é feito o controle explicito, por programa, de fluxos divergentes de execuções em threads. Apresentamos uma nova estrutura de dados compacta para lavouts de oetrees esparsas, bem como algoritmos paralelos para GPUs, tanto para transformações de lavouts como para eaminliamento paralelo usando a técnica de simulação de "warps"-largos (SWW, Simulated Wide-Warps), Os benefícios de nossas técnicas ocorrem devido à transposição do algoritmo de eamin- nhamento na árvore para execução em padrões mais regulares, possibilitando uma melhor adaptação ao modelo GPU paralelo, A estrutura de dados permite explorar localidades de acessos à memória durante os percursos, ao mesmo tempo conservando espaço em memória eaehe ou em memória compartilhada (scratchpad). Desta forma a memória rápida intra-eore pode ser dedicada a acelerar eaminliamentos. Controle divergência de fluxos também é delimitado de maneira algorítmica, impondo uma execução uniforme na maior parte dos segmentos de execução. Nossos experimentos mostram melhoria de desempenho significativa em relação às soluções em GPU mais conhecidas para este algoritmo. Desenvolvemos um novo algoritmo paralelo eficiente que gera diretamente de uma só vez as oetrees implícitas comprimidas, como um método massivamente paralelo. Este método traz uma nova visão para tratar de forma eficiente com a natureza irregular também presente na construção de oetrees esparsas, O algoritmo proposto de geração massivamente paralela de oetrees esparsas tem aplicação imediata em nossa implementação GPU paralela da simulação Barnes-Hut e em outros métodos de N-eorpos, As técnicas e algoritmos propostos nesta tese também poderão ser aplicadas em outros contextos. Palavras-chave: Algoritmo Massivamente Paralelo para Geração de Octrees; Octrees esparsas; Octree implícita; Probleamas de N-Corpos; Barnes-Hut; GPGPIJ; WarpsLargos Simulados em Software; CIJDA; Algoritmo Paralelo irregular; Algoritmos paralelos; Manycore Computing; Acelerador de Computação;
Abstract: The Barnes-Hut algorithm is a widely used approximation method for the N-Body simulation problem, which involves the construction and traversal of sparse trees at each simulation step and thus reducing the complexity to solve large/praetieal problems. The irregular nature of this tree walking code presents interesting challenges for its computation on parallel systems. Additional problems arise in effectively exploiting the processing capacity of GPU architectures. Octrees are data structures that efficiently represent spatial data in many fields such as scientific computing, computer graphics and image processing, among others. In this work we explicitly deal with dynamic irregular patterns in data accesses with data remapping and data transformation, depending on the data structures being accessed, and by controlling the execution flow divergence of threads. We present a new compact data-strueture for sparse octree layouts, and also GPU parallel algorithms for tree transformation and parallel walking using software Simulated Wide-Warps (SWW), Benefits of our techniques are in transposing the tree algorithm to execute regular patterns to match the GPU parallel model. The data structure allows exploring localities during traversals, at the same time conserving space in caches or scratchpad memory. This way fast intra-eore memory can be dedicated to speed up traversals. Control flow divergence is also algorithmically constrained, enforcing a mostly uniform execution of threads. Our experiments show significant performance improvement over the best known GPU solutions to this algorithm. We have developed a novel efficient parallel algorithm that directly generates entire compressed implicit octrees at once, as a massively parallel method. This method brings new insight on how to efficiently deal with the irregular nature of algorithms for constructing sparse octrees. The proposed algorithm has immediate application to our GPU parallel Barnes-Hut implementation and other N-Body methods. We envision that the techniques and algorithms proposed in this dissertation can also be applied in other contexts. Keywords: Massively Parallel Octree Generation Algorithm; Sparse Octrees; Implicit Octree; N-Body; Barnes-Hut; GPGPU; Software Simulated Wide-Warp; CUDA; Irregular Parallel Algorithm; Parallel algorithms; Many core Computing; Accelerator Computing;
21
Ryan, Timothy Lee. "Device independent perspective volume rendering using octrees." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09122009-040251/.
Full text
22
Shan, Haifeng. "Structure development in melt spinning, cold drawing and cold compression of poly(ethylene-co-octene) with different octene content." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1137341440.
Full textAbstract:
Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2006."May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, James L. White; Committee members, Avraam I. Isayev, Thein Kyu, Darrell H. Reneker, Shing-Chung "Josh" Wong; Department Chair, Sadhan C. Jana; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
23
Challapalli, Adithya. "Loading Mode Dependent Effective Properties of Octet-truss Lattice Structures Using 3D-Printing." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc799547/.
Full textAbstract:
Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic insulation, heat dissipation media and compact heat exchangers. In alignment with emerging additive manufacturing (AM) technology, realization of the structural applications of the lattice materials appears to be becoming faster. Considering the direction dependent material properties of the products with AM, by directionally dependent printing resolution, effective moduli of lattice structures appear to be directionally dependent. In this paper, a constitutive model of a lattice structure, which is an octet-truss with a base material having an orthotropic material property considering AM is developed. In a case study, polyjet based 3D printing material having an orthotropic property with a 9% difference in the principal direction provides difference in the axial and shear moduli in the octet-truss by 2.3 and 4.6%. Experimental validation for the effective properties of a 3D printed octet-truss is done for uniaxial tension and compression test. The theoretical value based on the micro-buckling of truss member are used to estimate the failure strength. Modulus value appears a little overestimate compared with the experiment. Finite element (FE) simulations for uniaxial compression and tension of octet-truss lattice materials are conducted. New effective properties for the octet-truss lattice structure are developed considering the observed behavior of the octet-truss structure under macroscopic compression and tension trough simulations.
24
Hermansson, Albin. "View-Dependent Collision Detection and Response Using Octrees." Thesis, Blekinge Tekniska Högskola, Institutionen för kreativa teknologier, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12751.
Full textAbstract:
Context. Collision is a basic necessity in most simulated environments, especially video games, which demand user interaction. Octrees are a way to divide the simulated environments into smaller, more manageable parts,and is a hierarchical tree-structure, where each node has eight children. Octrees and similar tree-structural methods have been used frequently to optimize collision calculations and partition the objects in the 3D space. Objectives. The aim of this thesis is to find a way to further improve upon the octree structure, by using a two-level octree structure, and simplify the collision of objects that do not demand much complexity, due to their size or the geometric simplicity of their 3D models, this is done by calculating how many pixels the objects occupy on the screen, and use that as a factor when deciding the depth of their individual octrees. Methods. Each object in the 3D environment is divided using an octree. These octrees generated for the objects are then placed in a larger octree. This large octree use the smaller ones to check collision between the objects. The pixel area occupied on the screen by the objects’ octrees is used to determine what depth of the octrees will be check for intersection. Two test scenes were set up to test our model. Results. Our implementation could effectively reduce the depth of octrees belonging to objects occupying little space on the screen. The experiments also showed that the reduced depth could be used with only a slight loss in accuracy. The accuracy loss increased when more objects were used. Conclusions. The results gained in the thesis show that the pixel area can be used effectively, and the simplified octrees can still represent the objects adequately, resulting in a cheaper but slightly less accurate collision.
25
Wood, James J. "A Historical and Analytical Examination of the Stravinsky Octet for Wind Instruments, with a Guide to Performance Preparation of the Two Trumpet Parts." Thesis, connect to online resource, 2007. http://digital.library.unt.edu/permalink/meta-dc-3593.
Full textAbstract:
Thesis (D.M.A.)--University of North Texas, 2007.System requirements: Adobe Acrobat Reader. Accompanied by recitals, recorded Mar. 22, 1999, Nov. 29, 1999, and Sept. 11, 2006. Includes bibliographical references (p. 52-53).
26
Hasert, Manuel [Verfasser]. "Multi-scale Lattice Boltzmann simulations on distributed octrees / Manuel Hasert." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1051504376/34.
Full text
27
Wilhelmsen, Audun. "Efficient Ray Tracing of Sparse Voxel Octrees on an FPGA." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19415.
Full textAbstract:
Ray tracing of sparse voxel octrees is a method of rendering images of 3D models, which could soon become practical for use in real time applications. This is desirable as ray tracing can produce very realistic visualizations, while voxel models can represent models with very fine geometric detail. For these reason the method has attracted significant attention in recent years, but no hardware solution has been published yet. This thesis presents a design of ray tracing of sparse voxel octrees in hardware. The objective is to show if it is sensible to implement the method in hardware, and if it could be integrated on modern GPUs alongside rasterization. To this end, the techniques used in existing software implementations of this method is reviewed, and an algorithm suitable for hardware implementation is presented. The problems of integrating the method with rasterization is explored, and the algorithm is analyzed and optimized to improve efficiency in hardware. A software implementation is presented, which supports the development of a hardware design. This design is implemented using the Verilog hardware description language, and it has been simulated and synthesized for an FPGA prototype. Multiple versions of the design has been synthesized and tested, and to evaluate the impact of design parameters the test results from these designs is presented. The thesis provides a comprehensive evaluation of the proposed design, and the results indicate that the algorithm is well suited for hardware implementation. Although real-time performance was not achieved, there are indications that further optimizations should allow real-time performance on the same platform, and that a full scale implementation on a modern GPU could probably allow ray tracing with a quality which is competitive with rasterization.
28
Sharma, Amit. "Catalytic Reaction Engineering using Ionic liquids : Hydroformylation of 1-Octene." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT015G/document.
Full textAbstract:
Une démarche de type génie de la réaction chimique est appliquée à l'hydroformylation modèle d'oct-1-ène par des complexes lipophobes du rhodium préparés à partir de Rh(CO)2(acac) en phase liquide ionique ([Bmim][PF6]) ou en phase liquide ionique supportée sur silice. La réaction étant contrôlée par la concentration des réactifs dans la phase liquide ionique catalytique, une première étape a consisté à mesurer ces concentrations tant pour les deux gaz (H2 et CO) que pour l'oct-1-ène à différentes températures et pressions. Diverses méthodes de mesures sont utilisées pour la solubilité de l'oléfine : thermogravimétrie et chromatographie gazeuse après extraction multiple d’espace de tête, en présence de solvant (décane) et du produit de la réaction (nonanal). Le transfert gaz-liquide, qui peut conditionner la vitesse de réaction dans ces milieux visqueux, est également mesuré par une technique dynamique de variation de pression, en liquide ionique pur et en mélange biphasique liquide ionique-phase organique, dans un réacteur autoclave à autoaspiration de gaz par arbre creux. Une corrélation générale est proposée montrant une forte influence de la vitesse d'agitation.Une étude cinétique est réalisée en conditions de transferts non limitants en gaz-liquide organique-liquide ionique avec la TPPTS comme ligand. Les comportements habituels de l’hydroformylation en phase organique ou en phase aqueuse sont retrouvés : ordre voisin de 1 pour H2, inhibition par CO à forte concentration, énergie d'activation élevée. Si le turnover est convenable (70 h-1), le rapport n/iso est par contre très bas ce qui n'est pas en faveur de ce système catalytique. Quelques résultats permettent aussi une première analyse de la catalyse biphasique avec le ligand sulfoxantphos et de la catalyse en phase liquide ionique supportée sur silice avec la TPPTSA chemical reaction engineering approach is applied to the hydroformylation of 1-octene using lipophobic complexes of rhodium prepared from Rh(CO)2(acac) in ionic liquid phase ([Bmim] [PF6]) or in the ionic liquid phase supported on silica. As the reaction is controlled by the concentration of the reagents in the catalytic ionic liquid phase, the concentrations of both gases (H2 and CO) and also of 1-octene are measured at various temperatures and pressures as an initial step. Different methods are used for the measurement of the olefin solubility inside the ionic liquid: thermogravimetry and multiple headspace chromatography, in the presence of solvent (decane) and reaction product (nonanal). The gas-liquid mass transfer, which can be a rate controlling step in these viscous media, is also measured by a dynamic technique of pressure variation, both in case of pure ionic liquid and biphasic mixture of ionic liquid and organic phase, in an autoclave reactor with self induced stirrer. A general correlation is proposed showing the strong influence of the agitation speed. A kinetic study is realized in no gas–liquid nor organic–ionic liquid mass transfer limiting conditions (chemical regime) with TPPTS as ligand. The usual hydroformylation behaviour is observed, as already found in organic phase or in aqueous phase: order close to 1 for H2, inhibition by CO at large concentration, and high activation energy. If the turnover frequency is suitable (70 h-1), the n/iso ratio is very low which is not favourable to this catalytic system. Some experimental results also allow a first analysis of biphasic catalysis with sulfoxantphos ligand and of ionic liquid phase supported catalysis with TPPTS ligand
29
Bardili, Nicolas. "Strömungssimulation inkompressibler Fluide auf Quad- bzw. Octrees mittels finiter Volumen." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10424235.
Full text
30
Schütte, Maya. "Chirale Organoarsenverbindungen für die Oxidationskatalyse." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961931027.
Full text
31
Möre, Tomas, and Gustav Schneider. "Comparing 3D-Clipmaps and Sparse Voxel Octrees for voxelbased cone tracing." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230105.
Full textAbstract:
Voxel based cone tracing is a promising approach to approximate globalillumination for real-time applications. This technique utilizes a voxelfield approximating the original scene to retrieve the necessary radi-ance information during sampling. The simplest approach to creat-ing a voxel field is to use a 3D texture. Since this requires too muchGPU memory for larger scenes alternative data structures are neces-sary. This thesis compares two seemingly suitable data structures 3D-Clipmaps and Sparse voxel octrees. To compare the two structures weimplement them using OpenGL and C++. We then use the improvedSponza model with additional dynamic objects to benchmark the dif-ferences between the two approaches. Both data structures has its prosand cons. Our conclusion is that Clipmaps seems to be the most prac-tical approach for real-world purposes.Voxel based cone tracing är ett lovande tillvägagångssätt för att ap-proximera global belysning för realtidsapplikationer. Denna teknik an-vänder ett voxelfält som approximerar den ursprungliga scenen för atthämta den nödvändiga ljusinformationen under sampling. Det enk-laste tillvägagångssätt för att skapa ett voxelfält är att använda en 3D-textur. Eftersom detta kräver för mycket GPU-minne för större scenermåste alternativa datastrukturer tas i hänsyn. Denna avhandling jäm-för två skenbart lämpliga datastrukturer 3D-Clipmaps och Sparse vox-el octrees. För att jämföra de två strukturerna implementerar vi demmed OpenGL och C++. Vi använder sedan den förbättrade Sponza-modellen med insatta dynamiska objekt att jämföra skillnaderna mel-lan de två metoderna. Båda datastrukturerna har sina fördelar ochnackdelar. Vår slutsats är att Clipmaps verkar vara det mest praktiskatillvägagångssättet för reella tillämpningar.
32
Reynders, Frederik Jakobus Wilhelm. "Gas-limited hydrogenation of 1-octene in a packed bed reactor." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/26555.
Full text
33
Wang, Youyou DeSouza Guilherme. "A compact representation for 3D animation using octrees and affine transformation." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6645.
Full textAbstract:
Title from PDF of title page (University of Missouri--Columbia, viewed on March 10, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Guilherme DeSouza. Vita. Includes bibliographical references.
34
Sigwinta, Mawande. "Ethylene-1-octene elastomers: Molecular structure characterization by advanced analytical methods." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/2993.
Full textAbstract:
Thesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2019Polyolefin elastomers are non-crystallising materials which are challenging to characterize with conventional crystallization-based techniques such as crystallization analysis fractionation (CRYSTAF) and temperature rising elution fractionation (TREF). However, interaction chromatography (IC) offers an alternative pathway for the chemical composition distribution definition of these materials. This work details the development of comprehensive characterization methods of linear low-density polyethylene (LLDPE) elastomers. In the first part of this work, four preparative fractionation methods namely, solution crystallization fraction (p-SCF), preparative temperature rising elution fractionation (p-TREF), modified p-TREF, and preparative molar mass fractionation (p-MMF) were compared for the analysis of an LLDPE elastomer with 12.8 mol% 1-octene content. While p-TREF showed the coelution effect at low elution temperatures, sufficient amount of fractions with narrow molar mass dispersity were obtained with the p-MMF method. Despite the limitations with the TREF method, it was demonstrated that both fractionation techniques provide detailed information on the complex nature of the LLDPE elastomer molecular structure after subsequent analysis with several other offline techniques such as solvent gradient interaction chromatography (SGIC). The modified p-TREF method also produced fractions with interestingly narrow dispersities and showed significant molar mass influence on its fractionation mechanism. The molar mass influence on the collected fractions was also observed with the p-SCF method, and both methods are a subject for future study. It was shown that when using a binary solvent mixture in which one of the solvents limits the solubility of the polyolefin chains, the separation is molar mass dependent even if column temperature is the active variable. In the second part of this work, four LLDPE copolymers with increasing amounts of 1-octene but similar molar masses were utilized to investigate the influence of chemical composition on the p-MMF technique. For all four LLDPE copolymers, eight fractions with decreasing molar masses were collected at different non-solvent/solvent ratios as the amount of non-solvent in the non-solvent/solvent mixture was increased. It was shown that chemical composition of these samples was independent of the fraction number, but was influenced by the average chemical composition of their respective bulk sample. Consequently, it was concluded that the molecular structure complexity of the four samples decreased with increasing 1-octene content. Finally, three commercial LLDPE elastomers with high 1-octene contents were comprehensively studied. Preparative molar mass fractionation was employed to obtain fractions which were further analysed using size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). It was found that at bulk level, the samples appear to exhibit microstructural homogeneity, however, their respective p-MMF fractions exhibit multimodal chemical composition distributions. Furthermore, the p-MMF fractions showed an increase in their chemical composition heterogeneity as the molar mass decreased. Ultimately, it was concluded that the p-MMF method is the most suitable technique that provides in-depth insight on the molecular structure complexity of LLDPE elastomers.
35
Taddeo, Leandro da Silva. "Detecção de colisão utilizando grids e octrees esféricas para ambientes gráficos interativos." Universidade de Fortaleza, 2005. http://dspace.unifor.br/handle/tede/70145.
Full textAbstract:
Made available in DSpace on 2019-04-05T23:03:29Z (GMT). No. of bitstreams: 0
Previous issue date: 2005-10-13Interactive graphical environments are becoming more present in our lives. Despite of the technological advances in the computing area for the development of these environments, there are still many challenges to overcome in order to simulate the world where we live in a realistic way. The collision detection treatment among 3D objects is a typical example. It still corresponds to one of the bottlenecks of the interactive graphical environments, whose control is basic for the production of convincing simulated results. This work presents some efficient collision detection methods (broad and narrow phases, using grids and spherical octrees, respectively), for the development of interactive graphical environments. A significative number of experiments was carried out, in which we varied the number of objects in the scenario, the geometry, the dimensions and the degree of complexity of the objects, as well as the level of detail of them. The obtained results, evaluated by means of subjective and usability metrics, show that the implemented detection methods achieve high performance and precision during the collision tests. Consequently, this guarantees the responsiveness success of the interactive graphical environment, as well as its robustness for a considerable number of complex and dynamic objects (200) represented simultaneously.
Ambientes gráficos interativos estão se tornando mais presentes em nossas vidas. Apesar dos avanços tecnológicos na área de computação para o desenvolvimento destes ambientes, ainda há muitos desafios a serem vencidos com o objetivo de simular o mundo em que vivemos de forma realista. O tratamento da detecção de colisão entre objetos 3D é um típico exemplo. Corresponde, ainda hoje, a um dos gargalos dos ambientes gráficos interativos, cujo controle é fundamental para a geração de resultados de simulação convincentes. Este trabalho apresenta alguns métodos eficientes de detecção de colisão (broad e narrow phases, utilizando grids e octrees esféricas, respectivamente), para o desenvolvimento de ambientes gráficos interativos. Um número significativo de experimentos foi conduzido, variando-se o número de objetos colidentes no cenário, as geometrias, as dimensões e o grau de complexidade dos objetos, bem como o nível de detalhe dos mesmos. Os resultados obtidos, avaliados por meio de métricas subjetivas e de usabilidade, mostram que os métodos de detecção implementados atingem alto desempenho e precisão durante os testes de colisão. Conseqüentemente, garantindo com sucesso o tempo de resposta do ambiente gráfico interativo, bem como a sua robustez para um número considerável de objetos complexos e dinâmicos (200) representados simultaneamente. Palavras Chave: Detecção de Colisão, octrees esféricas, malhas regulares (grids), ambientes gráficos interativos.
36
Arancibia, Román Nicolás Ignacio. "Modelamiento de un Generador de Mallas Basado en Octrees, Usando Patrones de Diseño." Tesis, Universidad de Chile, 2007. http://www.repositorio.uchile.cl/handle/2250/104718.
Full text
37
Yang, Sha. "Crystallization, Melting Behavior, Physical Properties, and Physical Aging of Ethylene/1-Octene Copolymers." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/72985.
Full textAbstract:
The time dependence of the physical properties of ethylene/1-octene (EO)-copolymers after primary crystallization is investigated by calorimetry, density, and creep measurements.
The temporal evolution of the multiple melting of EO-copolymers is monitored by differential scanning calorimetry. The low temperature endotherm displays an evolution similar to that observed for the enthalpy recovery in glasses after physical aging. Using this analogy, a calorimetry-aging rate is defined, which quantifies the change in the low endotherm temperature with time. Similarly a density-aging rate is defined from the evolution of density with time.
A non-classical creep behavior is observed for short aging times, consistent with crystallization-induced shrinkage. The change in crystallinity during aging leads to a change in the shape of the relaxation spectrum. Hence, analysis of creep data cannot be carried out using Struik's superposition method. For both short and long aging times, the creep rate exhibits a dependence on copolymer composition similar to those associated with the calorimetry- and the density-aging rates, suggesting a common origin for the evolution of the low endotherm, the creep behavior and the bulk density.
The calorimetry, density, and creep data are reexamined based on the following assumptions: First, a single population of small crystals is formed during crystallization at low temperature; Second, these small crystals increase in stability under isothermal conditions, easily melt and recrystallize during heating and serve as efficient thermo-reversible cross-links to increase the conformational constraints in the residual amorphous fraction. These assumptions appear to be consistent with all observations made to date.Master of Science
38
Yamazaki, Daisuke. "Structural and mechanistic studies on cyclic π-conjugated systems annelated with bicyclo〔2.2.2〕octene units." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136242.
Full text
39
Pang, Law Ma Rome Anne. "Beneath the Dancing Moon: A Composition for Woodwind and Percussion Ensemble." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc501224/.
Full textAbstract:
The composition is scored for the following instruments: 2 flutes, 2 oboes, 2 clarinets, 2 bassoons and a large percussion section requiring 7 performers. Beneath the Dancing Moon is a programmatic piece in one movement form composed of 5 continuous sections. It depicts a night scene when the elves begin to dance beneath the moon. Later, the moaning ghosts from the dark forest and the witches with brooms come to join them. They dance furiously until the moon disappears, the sea stops dead and all the dancers suddenly vanish. The approximate performance time is 17 minutes.
40
White, Bryan M. "Rotaxanated Polymers: I. Synthesis and Purification of Cyclic Polydimethylsiloxane II. Synthesis of Poly[octene-pseudorotaxa-(a-cyclodextrin)]." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5136.
Full textAbstract:
Polyrotaxanes possess a molecular architecture resembling that of a wheel and axle: linear polymer chains are threaded by cyclic molecules with no covalent bonds linking the two species. One of two methods can be employed for the preparation of polyrotaxanes: a template method to guide threading or an in situ polymerization of monomers in the presence of cyclic molecules. The research described in this dissertation was divided into two distinct sections, which were devoted to each method of polyrotaxane preparation.
The first step of synthesizing polyrotaxanes via the in situ polymerization method was to prepare a cyclic molecule. α,Ï -Dihydroxy-PDMS was cyclized and then efficiently purified by an anion-exchange resin to remove uncyclized, yet anionically charged, linear PDMS.
The second part of this dissertation included examining polyrotaxanes created by the template-directed threading of α-CD onto polyoctene (PO). End-capped PO, which was unthreadable by α-CD, was synthesized from 1,9-decadiene and a monovinyl bulky compound by acyclic diene metathesis. PO and ecPO each were sonicated in aqueous solutions of α -CD; PO formed a white precipitate indicative of a rotaxanated polymer, but no precipitate formed by the addition of ecPO. These results provided evidence that PO had been included within the cavity of α-CD.
41
Gong, Zhenxin. "Continuous flow homogeneous hydroformylation of 1-octene over supported ionic liquid phase rhodium catalysts using supercritical CO₂." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1877.
Full textAbstract:
The hydroformylation of 1-octene with supported ionic liquid phase catalyst was demonstrated when using a system involving the substrate, reacting gases and products in CO₂ and N₂ flow over a fixed bed supported ionic liquid phase catalyst (silica gel and carbon aerogels as solid support respectively) at different system pressures. Yields, reaction rates, selectivities and rhodium leaching were all monitored. A pressure of CO₂ flow just below the critical point of the flowing mixture (106 bar at 100 °C if no 1-octene has been converted) was the best condition for the hydroformylation. It gave the highest acitivity (conversion to aldehyde up to 70 %), fastest reaction (TOF up to 575.3 h⁻¹) and best stable selectivity ( l:b ratio reaching 3.37 ). The utilization of scCO₂ as reaction media leads to remarkable stability of the catalyst. The supercritical or near critical (expanded liquid) system completely overcame the progressive decrease in activity of catalyst at 50, 75 bar with liquid phase transport and also showed much better results than when using other gas flows such as N₂ flow at 100 bar. In the high pressure scCO₂ phase, the concentration of 1-octene at the catalyst bed was reduced so that the conversion to aldehyde was reduced. The pore size and surface groups of the solid support should be suitable for the SILP catalyst consisting of metal complex, excess ligand and ionic liquid. Using microporous carbon aerogels as the supports, whether activated or not, gave disappointing results.
42
Ramarou, Diteboho Selina. "Alkylated PTA platforms for mono- and polynuclear pre-catalysts for the aqueous biphasic hydroformylation of 1-octene." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29206.
Full textAbstract:
A series of mono-, di- and trimeric alkylated PTA ligands were synthesised. These ligands were reacted with the dimeric rhodium precursor, [RhCl(COD)]2, to produce the corresponding mono-, di- and trinuclear Rh(I)-PTA complexes. These complexes were then reacted with carbon monoxide to substitute the COD ligands with CO ligands, yielding the carbonyl analogues of the complexes. The ligands and complexes were fully characterised using various spectroscopic and analytical techniques, which include 1H, 13C and 31P NMR spectroscopy, FTIR spectroscopy, mass spectrometry, and elemental analysis. The ligands were found to have good solubility in water at room temperature, while the complexes showed water solubility at elevated temperatures. All the complexes were evaluated as catalyst precursors in the aqueous biphasic hydroformylation of 1-octene. The hydroformylation reactions showed that the complexes (6 – 18) were all active when used as catalyst precursors in the aqueous biphasic hydroformylation of 1-octene to yield aldehydes (linear and branched) and iso-octenes as side products. All complexes exhibited good chemoselectivity for aldehydes with the COD complexes displaying better chemoselectivity towards aldehydes than the CO complexes. However, the CO complexes exhibited better regioselectivity for linear aldehydes than the COD complexes. The trinuclear complex displayed accelerated catalytic rates than the dinuclear complexes which, in turn, displayed faster rates than the mononuclear complexes. The complexes could be recycled three times with a marked decrease in the conversion of 1-octene after each run for each catalyst precursor. Leaching studies showed a significant loss of the metal catalysts into the organic layer after each catalytic run. Mercury poisoning studies were conducted and confirmed that, under the catalytic conditions, all complexes behaved entirely as homogeneous catalysts when evaluated as catalyst precursors for the aqueous biphasic hydroformylation of 1-octene.
43
Klimach, Harald Verfasser], Sabine P. [Akademischer Betreuer] Roller, Marek [Akademischer Betreuer] [Behr, and Michael [Akademischer Betreuer] Resch. "Parallel multi-scale simulations with octrees and coupled applications / Harald Klimach ; Sabine P. Roller, Marek Behr, Michael Resch." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130402967/34.
Full text
44
Brittz, Geertruida. "Olefin skeletal isomerization of n-butene, n-hexene and n-octene using alumina-based catalysts / Geertruida (Trudie) Brittz." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8729.
Full textAbstract:
Stringent standards to improve air quality and to protect human health are continuously implemented due to the environmental impact of auto emissions. As a result, researching options for alternative components or alternative processes are very important to continuously improve the octane number in the fuel pool.
Therefore, by exploiting the high olefin (butene, hexene and octene) content part of the feedstocks, the overall aim of this study was to obtain olefin skeletal isomerization for the improvement of the RON in the refinery fuel pool. The influence of temperature variation (350 °C, 400 °C and 450 °C) on the performance of the different alumina catalysts (eta (η)-alumina, H-ZSM-5 and silicated alumina) was investigated. All experiments were performed using a fixed bed reactor at atmospheric pressure and a constant weight hourly space velocity of 5 h-1. The effect of the different conditions and additions on conversion and selectivity was determined.
Eta alumina and the silicated alumina (Siralox 40) were proved to be the catalysts that were most prone to cause skeletal isomerization when in contact with longer carbon chains. Butene did not isomerize to a significant extent when contacted over either Eta alumina or Siralox 40. In the case of the zeolite catalyst (ZSM-5), none of the feeds isomerized and it was speculated that it could have been due to the high activity of ZSM-5 which made this catalyst more likely to cause side reactions rather than the preferred skeletal isomerization reaction.Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2013
45
Sokolovicz, Yuri Clemente Andrade. "Reações em tandem de isomerização/metátese de 1-octeno como substrato modelo e de ésteres de óleos vegetais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/129743.
Full textAbstract:
O esgotamento de recursos fósseis aliado à poluição causada pelas fontes não renováveis clamam por novas rotas sustentáveis. Importante componente da biomassa são os óleos vegetais e esses possuem potencial para suprir a demanda não só de energia, mas também de produtos químicos e materiais. A isomerização e metátese de ésteres de óleos vegetais forma olefinas, ésteres e diésteres com diferentes comprimentos de cadeia carbônica e podem ser utilizados para produção de polímeros, dieseis, lubrificantes, detergentes, revestimentos de superfície, produtos farmacêuticos, cosméticos ou modificados para uma variedade enorme de outros compostos. Neste trabalho inicialmente foram estudadas reações em tandem de isomerização e metátese utilizando 1-octeno como substrato modelo. Dois sistemas foram utilizados para a captura de compostos voláteis em reações de isomerização/metátese. O sistema B de pressão atmosférica 1 atm (sistema aberto) apresentou melhor distribuição de produtos com cadeia longa e a maior captura de olefinas leves em comparação com o sistema A de pressão reduzida (sistema fechado). Estudou-se também o efeito da compatibilidade catalítica e a distribuição de produtos obtida pela combinação entre três catalisadores de metátese de olefinas Hoveyda Grubbs de primeira geração - HG1, Hoveyda Grubbs de segunda geração - HG2 e Umicore M42 - UM42 e dois catalisadores de isomerização de olefinas clorohidreto-carboniltris(trifenilfosfina)rutênio(II) - RuH e bromotriterc-butilfosfinapaladio-(I) - PdBr, no qual, a concomitância entre os catalisadores HG2 / RuH, UM42 / PdBr, HG2 / PdBr e HG2 / PdBr produziram espécies obedecendo uma distribuição em equilíbrio. Entretanto, quando foi utilizado HG1 / RuH não ocorreu formação do equilíbrio devido a aparente desativação do catalisador de isomerização RuH pela fosfina dissociada do catalisador HG1. Reações em tandem de isomerização/metátese a partir de ésteres de óleos de oliva e ésteres de óleo de girassol também foram investigadas. Três combinações entre catalisadores de isomerização e metátese, HG2 / RuH, UM42 / RuH e UM42 / PdBr, foram utilizadas e as combinações apresentaram diferentes distribuições de produtos olefínicos, ésteres e diésteres formados. Quando o substrato empregado foi o éster de óleo de oliva ocorreu a formação de três equilíbrios. Utilizando éster de óleo de girassol como substrato não ocorreu formação de equilíbrio devido a conjugação da dupla ligação. O catalisador de metátese de olefinas UM42 necessita ativação que é realizado pelos catalisadores de isomerização RuH e PdBr. Dois mecanismos foram propostos para explicar essas observações. A ativação do UM42 pelo RuH ou PdBr foi explicado pela formação de complexos B e C ou B e E, respectivamente. Foi sugerido que o complexo B com 14 elétrons seja ativo para metátese. Enquanto o complexo C e E podem formar espécies capazes de realizar isomerização de olefinas.The depletion of fossil resources combined with pollution from non-renewable sources clamoring for new sustainable routes. Important component of biomass are vegetable oils that can supply not only the energy, but also chemicals and materials demand. The isomerization and metathesis of vegetable oils esters form olefins, esters and diesters with different carbon chain lengths and may be used for producing of polymers, diesel, oils, detergents, surface coatings, pharmaceuticals, cosmetics or modified for a wide variety of other compounds. In this work, initially tandem isomerization/metathesis reactions of 1-octene as a model substrate were studied. Two systems were used for the capture of volatile compounds in isomerization/metathesis reactions. The system B (open system) showed a better product distribution for high-molecular weight olefins and best system for the capture of low molecular weight (“light”) olefins in comparison with system A (reduced pressure). The catalyst compatibility and product distribution obtained by combining three olefin metathesis catalysts Hoveyda Grubbs 1st generation - HG1, Hoveyda Grubbs 2nd generation - HG2 and Umicore M42 - UM42 and two olefin isomerization catalysts bromotri-tert-butylphosphine-palladium(I)dimer - PdBr e chlorohydridocarbonyltris(triphenylphosphine)-ruthenium(II) - RuH, in which the catalyst combinations HG2 / RuH, UM42 / PdBr, HG2 / PdBr and HG2 / PdBr operating in a Tandem fashion resulted in a mixture of products exhibiting an equilibrium distribution. However, when the combination HG1 / RuH was used the equilibrium did not occur, likely due to deactivation of the RuH isomerization catalyst by the dissociated phosphine from the metathesis catalyst HG1. Tandem isomerization/metathesis reactions of transesterified olive and sunflower oils were investigated. Three combinations of catalysts HG2 / RuH, UM42 / RuH and UM42 / PdBr showed different products distributions of olefins, esters and diesters. The formation of three equilibrium distributions could be observed when transesterified olive oil was used as substrate. When the substrate was transesterified sunflower oil, no equilibrium mixture was obtained due to the formation of conjugated double bonds. The olefin metathesis catalyst UM42 requires activation, which occurred in the presence of both isomerization catalysts RuH and PdBr. Two mechanistic pathways have been proposed to explain these observations. The activation of UM42 by RuH or PdBr was explained through the formation of the complexes B and C or B and E, respectively. The 14 electron complex B is suggested to be metathesis active, while the complexes C and E may form species able to perform olefin isomerization.
46
Sokolovicz, Yuri C. A. "Reações em tandem de isomerização/metátese de 1-octeno como substrato modelo e de ésteres de óleos vegetais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/129743.
Full textAbstract:
O esgotamento de recursos fósseis aliado à poluição causada pelas fontes não renováveis clamam por novas rotas sustentáveis. Importante componente da biomassa são os óleos vegetais e esses possuem potencial para suprir a demanda não só de energia, mas também de produtos químicos e materiais. A isomerização e metátese de ésteres de óleos vegetais forma olefinas, ésteres e diésteres com diferentes comprimentos de cadeia carbônica e podem ser utilizados para produção de polímeros, dieseis, lubrificantes, detergentes, revestimentos de superfície, produtos farmacêuticos, cosméticos ou modificados para uma variedade enorme de outros compostos. Neste trabalho inicialmente foram estudadas reações em tandem de isomerização e metátese utilizando 1-octeno como substrato modelo. Dois sistemas foram utilizados para a captura de compostos voláteis em reações de isomerização/metátese. O sistema B de pressão atmosférica 1 atm (sistema aberto) apresentou melhor distribuição de produtos com cadeia longa e a maior captura de olefinas leves em comparação com o sistema A de pressão reduzida (sistema fechado). Estudou-se também o efeito da compatibilidade catalítica e a distribuição de produtos obtida pela combinação entre três catalisadores de metátese de olefinas Hoveyda Grubbs de primeira geração - HG1, Hoveyda Grubbs de segunda geração - HG2 e Umicore M42 - UM42 e dois catalisadores de isomerização de olefinas clorohidreto-carboniltris(trifenilfosfina)rutênio(II) - RuH e bromotriterc-butilfosfinapaladio-(I) - PdBr, no qual, a concomitância entre os catalisadores HG2 / RuH, UM42 / PdBr, HG2 / PdBr e HG2 / PdBr produziram espécies obedecendo uma distribuição em equilíbrio. Entretanto, quando foi utilizado HG1 / RuH não ocorreu formação do equilíbrio devido a aparente desativação do catalisador de isomerização RuH pela fosfina dissociada do catalisador HG1. Reações em tandem de isomerização/metátese a partir de ésteres de óleos de oliva e ésteres de óleo de girassol também foram investigadas. Três combinações entre catalisadores de isomerização e metátese, HG2 / RuH, UM42 / RuH e UM42 / PdBr, foram utilizadas e as combinações apresentaram diferentes distribuições de produtos olefínicos, ésteres e diésteres formados. Quando o substrato empregado foi o éster de óleo de oliva ocorreu a formação de três equilíbrios. Utilizando éster de óleo de girassol como substrato não ocorreu formação de equilíbrio devido a conjugação da dupla ligação. O catalisador de metátese de olefinas UM42 necessita ativação que é realizado pelos catalisadores de isomerização RuH e PdBr. Dois mecanismos foram propostos para explicar essas observações. A ativação do UM42 pelo RuH ou PdBr foi explicado pela formação de complexos B e C ou B e E, respectivamente. Foi sugerido que o complexo B com 14 elétrons seja ativo para metátese. Enquanto o complexo C e E podem formar espécies capazes de realizar isomerização de olefinas.The depletion of fossil resources combined with pollution from non-renewable sources clamoring for new sustainable routes. Important component of biomass are vegetable oils that can supply not only the energy, but also chemicals and materials demand. The isomerization and metathesis of vegetable oils esters form olefins, esters and diesters with different carbon chain lengths and may be used for producing of polymers, diesel, oils, detergents, surface coatings, pharmaceuticals, cosmetics or modified for a wide variety of other compounds. In this work, initially tandem isomerization/metathesis reactions of 1-octene as a model substrate were studied. Two systems were used for the capture of volatile compounds in isomerization/metathesis reactions. The system B (open system) showed a better product distribution for high-molecular weight olefins and best system for the capture of low molecular weight (“light”) olefins in comparison with system A (reduced pressure). The catalyst compatibility and product distribution obtained by combining three olefin metathesis catalysts Hoveyda Grubbs 1st generation - HG1, Hoveyda Grubbs 2nd generation - HG2 and Umicore M42 - UM42 and two olefin isomerization catalysts bromotri-tert-butylphosphine-palladium(I)dimer - PdBr e chlorohydridocarbonyltris(triphenylphosphine)-ruthenium(II) - RuH, in which the catalyst combinations HG2 / RuH, UM42 / PdBr, HG2 / PdBr and HG2 / PdBr operating in a Tandem fashion resulted in a mixture of products exhibiting an equilibrium distribution. However, when the combination HG1 / RuH was used the equilibrium did not occur, likely due to deactivation of the RuH isomerization catalyst by the dissociated phosphine from the metathesis catalyst HG1. Tandem isomerization/metathesis reactions of transesterified olive and sunflower oils were investigated. Three combinations of catalysts HG2 / RuH, UM42 / RuH and UM42 / PdBr showed different products distributions of olefins, esters and diesters. The formation of three equilibrium distributions could be observed when transesterified olive oil was used as substrate. When the substrate was transesterified sunflower oil, no equilibrium mixture was obtained due to the formation of conjugated double bonds. The olefin metathesis catalyst UM42 requires activation, which occurred in the presence of both isomerization catalysts RuH and PdBr. Two mechanistic pathways have been proposed to explain these observations. The activation of UM42 by RuH or PdBr was explained through the formation of the complexes B and C or B and E, respectively. The 14 electron complex B is suggested to be metathesis active, while the complexes C and E may form species able to perform olefin isomerization.
47
Chowdhury, Rajarshi Roy. "Higher-order adaptive methods for fluid-dynamics." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS298.
Full textAbstract:
Les fluides (gaz et liquides) existent partout autour de nous. Alors que l’eau recouvre 70% de la croûte terrestre, des couches de gaz comme l’azote et l’oxygène entoure notre planète. Le domaine de la dynamique des fluides comprend l’étude des liquides ou des gaz en mouvement. Les équations qui régissent le mouvement des fluides à savoir les équations de Navier-Stokes sont des équations aux dérivées partielles non-linéaires complexes qui n’ont pas de solutions analytiques pour la plupart des problèmes d’intérêt pratique. Cependant, en utilisant des schémas numériques, ces équations aux dérivées partielles de variables continues peuvent être transformées en d’énormes systèmes algébriques de variables discrètes et résolues à l’aide d’ordinateurs à haute-performance. Une méthode numérique résolue sur un dispositif informatique introduira des erreurs dans la solution finale, nécessitera une quantité donnée de ressources de calcul comme la mémoire et le processeur, et prendra une quantité finie de temps pour parvenir à une solution. Ainsi, le développement d’algorithmes plus précis et plus rapides pour résoudre numériquement les équations d’un système de dynamique des fluides est un domaine de recherche en évolution constante. Le présent document est dédié à la fois à l’étude des algorithmes numériques d’ordre peu élevé, ainsi qu’à la mise en œuvre de méthodes existantes ou le développement et la mise en œuvre de nouvelles méthodes d’ordre supérieur, pertinentes pour la résolution des équations de Navier–Stokes incompressibles. L’ensemble du travail a été effectué sur le solveur adaptatif Cartésien d’équations fluides Basilisk. Nous recherchons en particulier des solveurs pour la convection–diffusion, les équations de Poisson–Helmholtz, les schémas temporels et les équations de Saint-Venant. Nous examinons des méthodes de maillage adaptatif pour résoudre ces équations et prenons l’implémentation de Basilisk de l’algorithme adaptatif en ondelettes sur quad-octree comme point de départ pour construire un nouveau schéma adaptatif d’ordre supérieur. Un thème récurrent tout au long de cette thèse est la comparaison de la précision et des performances informatiques de différents schémas d’ordre supérieur par rapport à leurs homologues d’ordre inférieurFluids (gases and liquids) exist everywhere around us. Water covers 70% of the Earth’s crust and gases like nitrogen and oxygen surround the planet. The field of fluid dynamics involves the study of liquids or gases in motion. The equations which govern the motion of fluids viz. The Navier–Stokes equations, are complex non-linear partial differential equations which do not have closed-form analytical solutions for most problems of practical interest. However, using numerical schemes, these partial differential equations of continuous variables can be transformed into huge algebraic systems of discrete variables and solved using high-performance computers. A numerical method solved on a computing device will introduce errors in the final solution, will require a given amount of computational resource like memory and processor, and will take a finite amount of time to reach a solution. Thus the development of more accurate and faster algorithms to numerically model the equations of fluid dynamics is a constantly evolving research field. The present document is dedicated to both the study of existing lower-order numerical algorithms as well as either the implementation of existing or development and implementation of new higher-order algorithms, relevant for solving the incompressible Navier–Stokes equations. The entire work has been carried out on the adaptive Cartesian solver for fluid equations Basilisk. We specifically research solvers for convection–diffusion, Poisson–Helmholtz equations, time-marching schemes, and for the shallow-water equations. We look at adaptive mesh methods for solving these equations and taking the Basilisk implementation of the adaptive wavelet algorithm on a quad-octrees as our starting point, we build a novel higher-order adaptive scheme. A recurring theme throughout this thesis is the comparison in accuracy and computing performance of different higher-order schemes when compared to their lower-order counterparts
48
Kumar, Amit. "Morphology, Crystallization and Melting Behavior of Statistical Copolymers of Propylene with Ethylene, 1-Butene, 1-Hexene and 1-Octene." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33563.
Full textAbstract:
In this thesis, the morphology, crystallization and melting behavior of polypropylene copolymers (propylene/ethylene, propylene/1-butene, propylene/1-hexene and propylene/1-octene) has been examined. The multiple melting behavior has been correlated with the presence of alpha and gamma phases and with the occurrence of cross-hatching morphology. The Crystallization and melting behavior of propylene/ethylene and propylne/1-butene are qualitatively similar and compatible with the expectations that the ethylene and butene comonomers are partly included in the propylene lattice. Propylene/1-hexene and propylene/1-octene copolymers exhibit remarkably similar behavior and morphologies consistent with the expectations that the hexene and the octene comonomers are rigorously excluded from the crystal lattice.
The origin and the crystallization time dependence of the multiple melting behavior is very different for these two pairs of copolymers. For PE and PB it is consistent with the melting of parent a-phase lamellae and alpha or gamma-phase daughter lamellae. For PH and PO copolymers it is very similar to that observed for ethylene-octene(EO) and ethylene-styrene(ES) copolymers and compatible with the melting of primary lamellae and secondary mosaic or fringed micellar structures.Master of Science
49
Frangov, Stoyan [Verfasser]. "Morphologie und Deformationsverhalten von Blends aus Polyethylen hoher Dichte und Ethylen-1-Octen-Copolymeren / Stoyan Frangov." Aachen : Shaker, 2005. http://d-nb.info/1181610028/34.
Full text
50
McShane, P. M. "Optimization of the morphological, mechanical and rheological properties of novel polypropylene/ethylene-octene copolymer blends for automotive fuel line protection applications." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268405.
Full text