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Dissertations / Theses on the topic 'Structural solution'
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Demers, Audrey Gertrude. "Structural studies of glycoproteins in solution." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054759177.
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Patriksson, Alexandra. "From Solution into Vacuum - Structural Transitions in Proteins." Doctoral thesis, Uppsala : University Library Universitetsbiblioteket, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8300.
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Saint-Georges, Pascal. "Iterative Solution of Linear Systems for FEM Structural Analysis." Doctoral thesis, Universite Libre de Bruxelles, 1996. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212345.
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Dicko, I. Cedric. "Structural changes in Nephila edulis silk proteins in solution." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400100.
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Stanic, Andjelka. "Solution methods for failure analysis of massive structural elements." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2383/document.
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Objectifs de la thèse : l’analyse à rupture de structure de type solides et membranes et la modélisation de la rupture quasi-fragile par la méthode des éléments finis à forte discontinuité en cas de solide 2D. Dans ce travail, la méthode de continuation avec une équation de contrainte quadratique est présentée sous sa forme linéarisée. En présence de ruptures locales, la méthode de continuation standard peut échouer. Afin d’améliorer la performance de cette méthode, nous proposons de nouvelles versions plus sophistiquées qui prennent en compte les ruptures locales des matériaux. D’une part, une version est basée sur une équation supplémentaire adaptative imposant une limitation. Cette version est considérée relativement satisfaisante pour les matériaux adoucissants. D’autres versions sont basées sur le contrôle de la dissipation incrémentale pour les matériaux inélastiques. Plusieurs formulations d’éléments finis à forte discontinuité sont présentées en détails pour l’analyse de rupture quasi-fragile. Les approximations discrètes du champ de déplacement sont basées sur des éléments quadrilatéraux isoparamétriques ou des éléments quadrilatéraux enrichis par la méthode des modes incompatibles. Afin de décrire la formation d’une fissure ainsi que son ouverture, la cinématique de l’élément est enrichie par quatre modes de séparation et des paramètres cinématiques. On a également proposé un nouvel algorithme de repérage de fissure pour l’évaluation de la propagation de la fissure à travers le maillage. Plusieurs exemples numériques sont réalisés afin de montrer la performance de l’élément quadrilatéral à forte discontinuité ainsi que l’algorithme de repérage de fissure proposéThe thesis studies: the methods for failure analysis of solids and structures, and the embedded strong discontinuity finite elements for modelling material failures in quasi brittle 2d solids. As for the failure analysis, the consistently linearized path-following method with quadratic constraint equation is first presented and studied in detail. The derived path-following method can be applied in the nonlinear finite element analysis of solids and structures in order to compute a highly nonlinear solution path. However, when analysing the nonlinear problems with the localized material failures (i.e. materialsoftening), standard path-following methods can fail. For this reason we derived new versions of the pathfollowing method, with other constraint functions, more suited for problems that take into account localized material failures. One version is based on adaptive one-degree-of-freedom constraint equation, which proved to be relatively successful in analysing problems with the material softening that are modelled by the embedded-discontinuity finite elements. The other versions are based on controlling incremental plastic dissipation or plastic work in an inelastic structure. The dissipation due to crack opening and propagation, computed by e.g. embedded discontinuity finite elements, is taken into account. The advantages and disadvantages of the presented path-following methods with different constraint equations are discussed and illustrated on a set of numerical examples. As for the modelling material failures in quasi brittle 2d solids (e.g. concrete), several embedded strong discontinuity finite element formulations are derived and studied. The considered formulations are based either on: (a) classical displacement-based isoparametric quadrilateral finite element or (b) on quadrilateral finite element enhanced with incompatible displacements. In order to describe a crack formation and opening, the element kinematics is enhanced by four basic separation modes and related kinematic parameters. The interpolation functions that describe enhanced kinematics have a jump in displacements along the crack. Two possibilities were studied for deriving the operators in the local equilibrium equations that are responsible for relating the bulk stresses with the tractions in the crack. For the crack embedment, the major-principle-stress criterion was used, which is suitable for the quasi brittle materials. The normal and tangential cohesion tractions in the crack are described by two uncoupled, nonassociative damage-softening constitutive relations. A new crack tracing algorithm is proposed for computation of crack propagation through the mesh. It allows for crack formation in several elements in a single solution increment. Results of a set of numerical examples are provided in order to assess the performance of derived embedded strong discontinuity quadrilateral finite element formulations, the crack tracing algorithm, and the solution methods
Doktorska disertacija obravnava: (i) metode za porušno analizo trdnih teles in konstrukcij, ter (ii) končne elemente z vgrajeno močno nezveznostjo za modeliranje materialne porušitve v kvazi krhkih 2d trdnih telesih. Za porušno analizo smo najprej preučili konsistentno linearizirano metodo sledenja ravnotežne poti skvadratno vezno enačbo (metoda krožnega loka). Metoda omogoča izračun analize nelinearnih modelov, ki imajo izrazito nelinearno ravnotežno pot. Kljub temu standardne metode sledenja poti lahko odpovedo,kadar analiziramo nelinearne probleme z lokalizirano materialno porušitvijo (mehčanje materiala). Zatosmo izpeljali nove različice metode sledenja poti z drugimi veznimi enačbami, ki so bolj primerne zaprobleme z lokalizirano porušitvijo materiala. Ena različica temelji na adaptivni vezni enačbi, pri katerivodimo izbrano prostostno stopnjo. Izkazalo se je, da je metoda relativno uspešna pri analizi problemov zmaterialnim mehčanjem, ki so modelirani s končnimi elementi z vgrajeno nezveznostjo. Druge različicetemeljijo na kontroli plastične disipacije ali plastičnega dela v neelastičnem trdnem telesu ali konstrukciji.Upoštevana je tudi disipacija zaradi širjenja razpok v elementih z vgrajeno nezveznostjo. Prednosti inslabosti predstavljenih metod sledenja ravnotežnih poti z različnimi veznimi enačbami so predstavljeni naštevilnih numeričnih primerih. Za modeliranje porušitve materiala v kvazi krhkih 2d trdnih telesih (npr. betonskih) smo izpeljali različne formulacije končnih elementov z vgrajeno močno nezveznostjo v pomikih. Obravnavane formulacije temeljijo bodisi (a) na klasičnem izoparametričnem štirikotnem končnem elementu bodisi (b) na štirikotnem končnem elementu, ki je izboljšan z nekompatibilnimi oblikami za pomike. Nastanek in širjenje razpoke opišemo tako, da kinematiko v elementu dopolnimo s štirimi osnovnimi oblikami širjenja razpoke in pripadajočimi kinematičnimi parametri. Interpolacijske funkcije, ki opisujejo izboljšano kinematiko, zajemajo skoke v pomikih vzdolž razpoke. Obravnavali smo dva načina izpeljave operatorjev, ki nastopajo v lokalni ravnotežni enačbi in povezujejo napetosti v končnem elementu z napetostmi na vgrajeni nezveznosti. Kriterij za vstavitev nezveznosti (razpoke) temelji na kriteriju največje glavne napetosti in je primeren za krhke materiale. Normalne in tangentne kohezijske napetosti v razpoki opišemo z dvema nepovezanima, poškodbenima konstitutivnima zakonoma za mehčanje. Predlagamo novi algoritem za sledenje razpoki za izračun širjenja razpoke v mreži končnih elementov. Algoritem omogoča formacijo razpok v več končnih elementih v enem obtežnem koraku. Izračunali smo številne numerične primere, da bi ocenili delovanje izpeljanih formulacij štirikotnih končnih elementov z vgrajeno nezveznostjo in algoritma za sledenje razpoki kot tudi delovanje metod sledenja ravnotežnih poti
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Steinke, Nicola. "Structural investigations of peptide folding and unfolding in solution." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:753c28d5-cb84-4a40-9048-bbaf98e9057c.
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Proteins are the essential biological working molecules in all living beings. Their function depends on their ability to adopt a specific three-dimensional structure in aqueous solution. The mechanism of this folding process, and conversely the loss of protein structure, unfolding, is still not well understood, especially on the atomic scale where these interactions occur in vivo. In this thesis, the structures of small model peptides have been investigated in aqueous solutions in order to understand how water, urea and other co-solutes influence protein folding and unfolding. Using a combination of neutron diffraction enhanced by isotopic substitution and computer simulations, it was found that urea, generally at any probed concentration, decreases ionic interactions with the peptides in solution. When the peptide backbone is solvent accessible, urea interacts directly with the polar peptide backbone and replaces water molecules at higher urea concentrations. Further, the results indicate an ambiguous in uence of water on peptide folding vs. conformational stability. The formation of β-turn like structures, and possibly intra-peptide hydrogen bonds in general, appears to be dependent on a specific backbone hydration pattern, facilitated by the local amino acid sequence. Conversely, hydrophobic residues in folded protein structures are particularly sensitive, in terms of conformation and hydration, towards an increased peptide backbone hydration.
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Doan, Vinh Thi Thuy. "Integrated design solution of a residential structural insulated panel dwelling." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4236/.
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In the transition pathway to low carbon construction, the UK Government affirms the legal commitment of reducing carbon dioxide emissions associated with energy use in buildings. There have been some successes achieved by the use of Structural Insulated Panels (SIPs), a ready insulated and prefabricated product that offers positive benefits in energy efficiency. However, detailed field performance of SIP units are still relatively rare in the UK, and issues related to thermal bridging and other as-built effects on thermal performance coupled to lack of ventilation potential have not been fully assessed. A systematic post construction evaluation of a SIP based dwelling was conducted by means of analytical verification, thermo-dynamic computer simulation, and field experimental work. Focus throughout was on generating post construction performance data, which have been used to validate and verify models developed in simulation software to understand how gap between design and post construction performance can be closed. Consideration of a SIP based product was particularly important as this solved a number of challenges faced by the UK housing sector, particularly the need for cost effective and energy efficient solutions whose performance under a range of changing conditions or orientations can be predicted.
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Gopalasingam, Piraveen. "Structural characterization of the protein tyrosine phosphatase Shp2 in solution." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5828/.
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Intracellular signalling cascades are mediated by a plethora of receptors, enzymes, adaptors and small molecules. The Protein Tyrosine Phosphatase (PTP) Shp2 is a highly conserved enzyme involved in a myriad of cellular processes including growth, differentiation and apoptosis. Shp2 is multi-domain protein composed of two SH2 domains in tandem, a PTP catalytic domain and a C-terminal tail containing multiple phosphorylation sites and a proline-rich region. The majority of biophysical research has utilised X-ray crystallography to study interactions and effects of mutations at the structural level. To gain a further understanding of Shp2 ligand binding and perturbations caused by disease relevant mutations, a structural investigation was performed with Nuclear Magnetic Resonance (NMR) spectroscopy and Small-angle X-ray Scattering (SAXS) in solution. The NMR signals from the backbone of both SH2 domains were assigned and residue-level interactions and differential SH2 domain specificities with peptides from the novel receptor G6b-B were delineated. In addition, the E76K point mutation that causes Noonan Syndrome and leukaemia was found to have increased conformational dynamics, the first experimental evidence of this phenomenon at the structural level.
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Thareja, Rajiv R. "Efficient single-level solution of hierarchical problems in structural optimization." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71195.
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Engineering design is hierarchical in nature, and if no attempt is made to benefit from this hierarchical nature, design optimization can be very expensive. There are two alternatives to taking advantage of the hierarchical nature of structural design problems. Multi-level optimization techniques incorporate the hierarchy at the formulation stage, and result in the coordinated optimization of a hierarchy of subsystems. The use of multi-level optimization techniques often necessitates the use of equality constraints. These constraints can sometimes cause numerical difficulties during optimization. Single-level decomposition techniques take advantage of the hierarchical nature to reduce the optimization cost.
In this research the decomposition approach has been followed to reduce the computational effort in a single-level design space. A decoupling technique has been developed that retains the advantages of a partitioned system of smaller independent subsystems without an increase in the total number of design variables. A penalty function formulation using Newton's method for the solution of a sequence of unconstrained minimizations was employed. The optimization of the decoupled system is cheaper due to (i) cheaper evaluation of the hessian matrix by taking advantage of its sparsity, (ii) fewer global analyses for constraint derivative calculations, and (iii) utilizing the decoupled nature of the hessian matrix in the solution process. Further, the memory requirements of the decoupled system are much less than that of the original coupled system. These benefits increase substantially for design problems with larger and larger number of detailed design variables.
Orthotropic material properties as stiffness global variables have been shown to be effective as global variables for panels in a hierarchical wing design formulation.
The proposed decoupling technique was implemented to minimize the volume of a portal frame and a wing box. Computational savings of up to 50 percent have been obtained for medium sized problems. The savings increase as the size of the problem and the amount of decoupling is increased. The procedure is simple to implement. For truly large systems this decoupling technique provides the necessary reduction of computational effort to make the optimization process viable.Ph. D.
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Borges, Rafael Junqueira. "Structural studies of PLA2-like toxins and development of the structure solution method sequence slider." Botucatu, 2017. http://hdl.handle.net/11449/150292.
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Orientador: Marcos Roberto de Mattos FontesResumo: As fosfolipases A2 (PLA2s) são um dos maiores constituintes protéicos do veneno botrópico e um dos responsáveis pela necrose muscular, consequência esta não eficazmente neutralizada pela administração do soro antiofídico. Estas proteínas são tóxicas através do rompimento ou perturbação da membrana celular em um mecanismo catalítico dependente de cálcio e outro independente, sendo este último não totalmente elucidado. Usualmente, estas toxinas são obtidas diretamente do veneno das serpentes, sendo sua purificação um desafio pela co-existência de diferentes isoformas. O objetivo desta tese foi compreender o mecanismo miotóxico independente de cálcio através de estudos estruturais e propor nova metodologia que trate de dados cristalográficos de toxinas provenientes de amostras impuras, chamada SEQUENCE SLIDER. Para tanto, cristalografia e outras técnicas biofísicas, como espalhamento de raios X a baixo ângulo, serão utilizados para estudar três miotoxinas ofídicas em estado nativo e complexado com produtos naturais e inibidores. Nós propusemos medidas locais e globais para caracterizar e relacionar a estrutura dessas toxinas a função. Com o SEQUENCE SLIDER, pudemos elucidar as estruturas de toxinas inéditas cuja sequência era parcialmente conhecida. Esta nova metodologia proposta consiste em avaliar diferentes cadeias laterais contra o coeficiente de correlação em espaço real calculado a partir dos dados cristalográficos. Em paralelo, desenvolvemos o SEQUENCE SLIDER no âmbito do... (Resumo completo, clicar acesso eletrônico abaixo)
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Sidhu, Jagraj. "Equilibrium and structural studies of polymer / surfactant assemblies in aqueous solution." Thesis, University of Salford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420463.
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Lulec, Andac. "Solution Of Sparse Systems On Gpu Architecture." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613355/index.pdf.
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The solution of the linear system of equations is one of the core aspects of Finite Element Analysis (FEA) software. Since large amount of arithmetic operations are required for the solution of the system obtained by FEA, the influence of the solution of linear equations on the performance of the software is very significant.
In recent years, the increasing demand for performance in the game industry caused significant improvements on the performances of Graphical Processing Units (GPU). With their massive floating point operations capability, they became attractive sources of performance for the general purpose programmers. Because of this reason, GPUs are chosen as the target hardware to develop an efficient parallel direct solver for the solution of the linear equations obtained from FEA.
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Liu, Hongbo. "Investigation of new multiferroic materials with coexistence of several ferroic and structural instabilities." Phd thesis, Ecole Centrale Paris, 2011. http://tel.archives-ouvertes.fr/tel-00711475.
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Multiferroics are currently intensely investigated because the coexistence and coupling of ferroic arrangements brings about new physical effects and, for the few room-temperature examples, interesting prospects for applications in various fields. This interest is illustrated by the recent publication of several articles on multiferroics in high impact reviews over the last five years. The main goal of the thesis was to look for new multiferroics by exploiting overlooked and original polar and magnetic arrangements. We more precisely investigated compounds based on lead iron tungsten PbFe2/3W1/3O3 (PFW) and lead zirconate PbZrO3 (PZO) oxides. PFW displays long- and short-range both polar and magnetic orders (ferroelectric-relaxor and antiferromagnetic-spin-glass) while PZO is antiferroelectric with antiferrodistorsivity (oxygen tilts) and existence of ferroelectric instabilities. Combining various techniques from synthesis to electric, magnetic and structural characterizations, we demonstrated that it is possible to get a multiferroic compound (50%PFW-50%PZO) with coexistence of multiple ferroic and structural arrangements with room temperature properties of practical interest. This work opens new prospects in this rich field of multiferroics in peculiar by using antiferroelectrics.
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Shen, Zhenyuan. "An integrated finite strip solution for long span bridges /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202009%20SHEN.
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Cowling, Charlene Anne. "Structural and brief solution focused therapies with families experiencing parent-adolescent conflict." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51697.pdf.
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Rugonyi, Sandra 1970. "A simultaneous solution procedure for fully coupled fluid flows with structural interactions." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80022.
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Doerdelmann, Thomas. "Structural and Biophysical Studies of the Pitx2 Homeodomain." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307443112.
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Kindahl, Lill. "Structural studies of saccharides and glycopeptides in aqueous solution by ¹H NMR spectroscopy /." Uppsala : Dept. of Chemistry, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a377.pdf.
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Coleman, Keenan L. "On the numerical solution of the integral equation formulation for transient structural synthesis." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43891.
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Approved for public release; distribution is unlimitedStructural synthesis is the analysis of the dynamic response of a system when either subsystems are combined (substructure coupling) or modifications are made to substructures (structural modification). The integral equation formulation for structural synthesis is a method that requires only the baseline transient response, the baseline modal parameters, and the impedance of the structural modification. The integral formulation results in a Volterra integral equation of the second-kind. An adaptive time-marching scheme is utilized to solve the integral equation formulation for structural synthesis. When structural modifications of large magnitude are made, the solution to the integral equation can become unstable. To overcome this conditional stability, the derivative of the synthesis equation is examined and demonstrated to be stable regardless of the magnitude of the structural modification.
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Stephens, Alan Nicholas. "Niobium dithiocarbamates : structural and solution studies in relation to a bridged-dinitrogen complex." Thesis, University of Sussex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236255.
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Webb, Michael Rene. "Structural and solution determinants of DNA intercalation and topoisomerase IB inhibition of flavonoids /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Rhys, Natasha Hazel. "Exploring the structural properties of natural and synthetic biological molecules in aqueous solution." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11248/.
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Peptoids are synthetic mimics of naturally-occurring peptides (the natural building blocks of proteins). These interesting building blocks are more resistant to temperature, pH and solvent denaturation, and possess a more exible backbone compared to their peptide counterparts. As a result, peptoids are emerging as promising biomimetic materials for a range of applications. Despite this potential, very little is known about the intermolecular interactions which determine their stability and solubility, including hydrogen-bonding, hydrophobic interactions and hydration properties, as well the structural properties of the individual imino acid blocks that make them. This thesis presents neutron diffraction experiments coupled with isotopic substitution and computational modelling to complete a structural study on a model imino acid in aqueous solution. The focus here has been on glutamine, a molecule that is capable of forming multiple hydrogen bonds and is thought to self-assemble through preferential side-chain hydrogen bond interactions, making it an interesting model system. Furthermore, glutamine is important in many biochemical processes and its presence has been associated with a number of neurodegenerative diseases. By probing the structural properties of the model system in aqueous solution and of its amino acid equivalent, L-glutamine, it has been possible to uncover details of important intermolecular interactions that govern the properties of these biomolecules. The interactions of the model imino acid have also been observed with respect to temperature and concentration and compared to a naturally-occurring imino acid, sarcosine, to determine the impact of side chain on imino acid interactions. This work also serves as a reference for completing structural studies on such biomolecules, covering methodological benefits and limitations. This is the necessary first step in building a framework to understand the self-assembly and driving forces in more complex peptoid and peptide structures and serves as a reference for completing neutron studies on natural and synthetic biomolecules.
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Kurc, Ozgur. "A Substructure Based Parallel Solution Framework for Solving Linear Structural Systems with Multiple Loading Conditions." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6923.
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This study presented a substructure based parallel linear solution framework for the static analysis of linear structural engineering problems having multiple loading conditions. The framework was composed of two separate programs designed to work on PC Clusters having the Windows operating system. The first program was responsible for creating the optimum substructures for the parallel solution and first partitioned the structure in such a way that the number of substructures was equal to the number of processors. Then, the estimated condensation time imbalance of the initial substructures was adjusted by iteratively transferring nodes from the substructures with slower estimated condensation times to the substructures with faster estimated condensation times. Once the final substructures were created, the second program started the solution. Each processor assembled its substructures stiffness matrix and condensed it to the interface with other substructures. The interface problem was solved by a parallel variable band solver. After computing the interface unknowns, each processor calculated the internal displacements and element stresses or forces. Examples which illustrate the applicability and efficiency of this approach were also presented. In these examples, the number of processors was varied from one to twelve to demonstrate the performance of the overall solution framework.
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Arzt, Markus. "Approche des phénomènes cycliques par la méthode à grand incrément de temps." Cachan, Ecole normale supérieure, 1994. http://www.theses.fr/1994DENS0014.
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Ce travail est l'application d'un algorithme à grand incrément de temps pour l'analyse de problèmes d'évolution en temps. Contrairement aux méthodes classiques basées sur le schéma pas à pas, l'ensemble du chargement est étudié en un seul grand incrément. Il s'agit d'une analyse non linéaire de structures soumises à un chargement cyclique. La relation de comportement viscoplastique du matériau est décrite par variables internes. Une formulation standard et normale permet de définir des directions de recherche à partir de l'operateur tangent afin de réduire le nombre d'itérations de la méthode. Une technique utilisant deux échelles de temps est développée pour diminuer les calculs numériques des simulations. Une comparaison des résultats obtenus par un calcul classique est effectuée dans le cas d'un problème simple. Les résultats pour une structure comportant de l'ordre de 3000 degrés de liberté soumise à un chargement de 1000 cycles sont également présentés
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Wik, Greger. "Headbox Slice Opening Arrangement : An Alternative Solution for Tissue Machines." Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7408.
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The head box in a tissue machine distributes the fiber suspension to a flat jet along the width of the machine. By adjusting the so-called lip opening, the flow is regulated and the jet is accelerated to match the machine speed. In this work, ideas for alternative solutions for lip opening mechanism is generated and evaluated with a focus on making a cost saving. One of the concepts has been selected for a deeper analysis with respect to the design, strength and cost. The selected concept is based on reducing the number of jacks required by using one jack operating a shaft parallel to the apron beam. Levers convey the movement to the apron beam. The analysis show that the shaft is exposed to high torque which results in large elastic twisting of the shaft, which means that the force that supports the apron beam will not be equal over the entire width. If the difference in force is too big, the apron beam will twist which results in an uneven lip opening. The shaft stiffness is therefore crucial. For the head box with a width of 2946 mm, the number of jacks is reduced from three to one. Wider head boxes may need more than one jack since the shaft cannot be made to long without getting too much twisted. A lip opening mechanism of the current design with six 20 ton jacks can be compared to the new concept in which only two jacks is needed and the cost is reduced by 18%. There is further potential for savings if the jack, separate gear and electric motor are replaced with an actuator that has the motor mounted directly.Inloppslådan i en tissuemaskin har till uppgift att fördela fibersuspensionen till en flat stråle längs maskinens bredd. Genom att justera den så kallade läppöppningen regleras flödet och strålen accelereras för att passa maskinhastigheten. I detta arbete har idéer till alternativa lösningar för läppöppningsmekanismen genererats och utvärderats med fokus på att göra en kostnadsbesparing. Ett av koncepten har valts ut för en djupare analys med avseende på konstruktion, hållfasthet och kostnad. Det valda konceptet bygger på att reducera antalet domkrafter som behövs genom att en domkraft driver en axel parallell med utloppsbordet. Hävarmar överför rörelsen till utloppsbordet. Analysen visar att axeln utsätts för ett stort moment vilket ger en stor elastisk vridning av axeln, vilket gör att kraften som håller emot utloppsbordet inte blir lika stor över hela bredden. Om skillnaden i kraft är för stor ger det en förvridning av utloppsbordet som resulterar i en ojämn läppöppning. Axelns styvhet är alltså avgörande. För den undersökta lådan med bredden 2946 mm har antalet domkrafter reducerats från tre stycken till en. För bredare inloppslådor behövs fler domkrafter då axeln inte kan göras för lång utan att få för mycket vridning. Ett läppöppningsarrangemang som idag har sex stycken domkrafter kan jämföras med det nya konceptet där det krävs endast två domkrafter och kostnaden minskas med ca. 18%. Ytterligare potential till besparing finns om man byter ut domkraft, separat växel och elmotor till ett ställdon som har motorn direktmonterad.
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Renken, Jay A. "Optimal solution selection for sensitivity-based finite element model updating and structural damage detection." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA306053.
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Thesis (M.S. in Mechanical Engineering and Mechanical Engineer) Naval Postgraduate School, December 1995.Thesis advisor(s): Joshua H. Gordis. "December 1995." Includes bibliographical references. Also available online.
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Schmidt, Jan Henrik [Verfasser]. "An efficient solution procedure for elastohydrodynamic contact problems considering structural dynamics / Jan Henrik Schmidt." Karlsruhe : KIT Scientific Publishing, 2019. http://www.ksp.kit.edu.
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MILANI, CARLOS AUGUSTO RUPPENTHAL. "IDENTIFICATION AND SOLUTION OF HOT ROLLING CRACKING IN STRUCTURAL STEELS PROCESSED BY CONTINUOUS CASTING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36911@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO advento e consolidação do processo de lingotamento contínuo, hoje dominante no setor siderúrgico, trouxe à tona os crescentes esforços de investigação e análise dos fenômenos relacionados com o comportamento dos aços a elevadas temperaturas. Diferentemente do lingotamento convencional, o lingotamento contínuo é um processo dinâmico no qual ocorre a oscilação do molde enquanto o veio em solidificação é continuamente extraído ao mesmo tempo que é submetido a um segundo resfriamento dito secundário. No Brasil há um parque industrial de empresas que se dedicam à laminação a quente de semiacabados fornecidos por terceiros como placas de aço, as quais são cortadas a quente sob a forma de tarugos de seção quadrada que são então destinados a laminação. A linha de produção dessas empresas compreende basicamente produtos estruturais tais como barras chatas, barras redondas, barras quadradas, cantoneiras e até perfis especiais destinados à indústria automobilística e de máquinas. Uma série catastrófica de eventos de qualidade relacionados com trincas emergiu da laminação de tarugos de aço SAE 1020 oriundos de placas continuamente lingotadas. Essas trincas, porventura preexistentes ou latentes no interior das placas podem ter sido exacerbadas por efeitos de zonas termicamente afetas durante as operações de corte. A solução proposta para superação dessa contingência foi então a de criação de um aço de substituição com teores inferiores de carbono e maior conteúdo de ligas que preservasse as propriedades mecânicas do material laminado. Teores inferiores de carbono não apenas contribuem para a minimização dos efeitos oriundos das transformações peritéticas como também agem favoravelmente sobre as consequências decorrentes de zonas termicamente afetadas. Essa proposta foi bem sucedida e a composição química desse aço de substituição denominado pseudo-1020 passou a ser desde então padrão de laminação. Amostras do SAE 1020 laminado com ocorrências de trincas e do aço de substituição foram obtidas e transformadas em corpos de prova para a realização de ensaios de tração, dureza e impacto. Essa dissertação objetiva apresentar toda a fenomenologia relacionada com a ocorrência de trincas superfícies e internas em aços continuamente lingotados, em especial os submetidos a transformações peritéticas, e as premissas que fundamentaram a criação do aço de substituição e os resultados auferidos.
The advent and consolidation of the continuous casting process, currently dominant in the Steel Industry, raised the increasing investigation and analyses efforts on the phenomena related to the high-temperature behavior of the steels. Unlike the conventional ingot casting process, the continuous casting is a dynamic process in which occurs the mold oscillation while the strand under solidification is continuously withdrawn and submitted to a secondary cooling operation. In Brazil, it can be found an industrial park of companies dedicated to the hot rolling of semis supplied by third parties as steel slabs, which ones are flame cut in the form of square billets for rolling. The production mix of these companies encompasses structural steels such as flat bars, round bars, angles and even special profiles for the machines and automotive industries. A catastrophic series of quality events related to cracking emerged from the rolling of SAE 1020 billets made from continuously cast slabs. These cracks, perhaps pre-existing or latent in the inner parts of the slabs could be exacerbated by thermal affected zones during the flame-cut operations. The propose solution to overcoming this contingency was the creation of a replacement steel grade with lower carbon content and higher alloy content aiming to preserve the mechanical properties of the as rolled material. Lower carbon contents does not only contributes to the minimization of the effects arising from the peritetic transformations as also act in favor on the consequences coming from thermal affected zones. This proposition was well successful and the chemical composition of this replacement steel called pseudo- 1020 since then became a rolling standard. Samples of the rolled SAE 1020 steel with cracks occurrences and of the replacement steel were taken and transformed in specimens for tensile strengths, hardness and impact tests.This paper aims to present all related phenomena to the occurrence of inner and superficial cracks in continuously cast steels, in special the ones submitted to peritetic transformations, and the premises that support the creation of a replacement steel and the related results.
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Mendes, Luis Felipe Santos. "Structural and dynamic characterization of the Golgi Reassembly and Stacking Protein (GRASP) in solution." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-18042018-094959/.
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The Golgi complex is an organelle responsible for receiving synthesized cargo from the endoplasmic reticulum for subsequent post-translations modifications, sorting and secretion. A family of proteins named Golgi Reassembly and Stacking Proteins (GRASP) is essential for the correct assembly and laterally tethering of the Golgi cisternae, a necessary structuration to keep this organelle working correctly. The GRASP structure is mainly composed of two regions: an N-terminal formed by two PDZ domains connected by a short loop (GRASP domain) and a non-conserved C-terminal region, rich in serine and proline residues. Although there are now a few crystal structures solved for the N-terminal domain, it is surprising to notice that no information is currently available regarding a full-length protein or even about dynamic and structural differences between the two PDZs in solution, which is the main functional region of this protein. Using a full-length GRASP model, we were capable of detecting the coexistence of regular secondary structures and large amounts of disordered regions. The overall structure is less compact than a regular globular protein and the high structural flexibility makes its hydrophobic core more accessible to solvent. GRASP coexist in a dynamic conformational ensemble of a µs-ms timescale. Our results indicate an unusual behavior of GRASP in solution, closely resembling a class of collapsed intrinsically disordered proteins called molten globule. We report here also the disorder-to-order transition propensities for a native molten globule-like protein in the presence of different mimetics of cell conditions. Changes in the dielectric constant (such as those experienced close to the membrane surface) seem to be the major factor capable of inducing several disorder-to-order transitions in GRASP, which seems to show very distinct behavior when in conditions that mimic the vicinity of the membrane surface as compared to those found when free in solution. Other folding factors such as molecular crowding, counter ions, pH and phosphorylation exhibit lower or no effect on GRASP secondary structure and/or stability. This is the first study focusing on understanding the disorder-to-order transitions of a molten globule structure without the need for any mild denaturing condition. Regarding the PDZs that form the GRASP domain, we observed that GRASPs are formed by a more unstable and flexible PDZ1 and much more stable and structurally well-behaved PDZ2. More than that, many of the unstable regions found in PDZ1 are in the predicted binding pocket, suggesting a structural promiscuity inside this domain that correlates with the functional promiscuity of interacting with multiple protein partners. This thesis presents the first structural characterization of a full-length GRASP, the first model of how GRASPs (or any molten globule-like protein) can be modulated by the cell during different cell functionalities and the first work in the community proving that the established idea that both PDZs are structurally equivalent is not completely rightO complexo de Golgi é um organela responsável pela recepção de carga sintetizada no retículo endoplasmático e por subsequente modificações pós-traducionais, classificação e secreção. Uma família de proteínas chamada Golgi Reassembly and Stacking Proteins (GRASP) é essencial para o correto empilhamento das cisternas e conexões laterais das pilhas do complexo de Golgi, uma estruturação necessária para manter essa organela funcionando corretamente. A estrutura das GRASPs é composta de duas regiões principais: uma extensão N-terminal formado por dois domínios PDZ conectados por um loop (domínio GRASP) e uma região C-terminal não conservada, rica em resíduos de serina e prolina. Embora existam algumas estruturas cristalográficas resolvidas para o domínio N-terminal, é surpreendente notar que não havia nenhuma informação na literatura sobre a construção inteira de um GRASP, ou mesmo um estudo detalhado sobre os PDZs no N-terminal em solução, que é a principal região funcional dessa proteína. Usando um modelo de GRASP em sua construção completa, fomos capazes de detectar a coexistência de estruturas secundárias regulares e grandes quantidades de regiões desordenadas. A estrutura é menos compacta do que uma proteína globular e a alta flexibilidade estrutural torna o seu núcleo hidrofóbico mais acessível ao solvente. GRASPs coexistem em um conjunto conformacional dinâmico numa escala de tempo característico de s-ms. Nossos resultados indicam um comportamento incomum da GRASP em solução, similar à de uma classe de proteínas intrinsicamente desordenadas colapsadas conhecidas como glóbulos fundidos. Nós relatamos também as propensões de transição estrutural do tipo desordem-ordem para uma proteína glóbulo fundido nativa, induzidas pela presença de diferentes miméticos de condições celulares especificas. A mudança na constante dielétrica do meio (como as experimentadas próximas à superfície da membrana biológica) é o principal modulador estrutural, capaz de induzir múltiplas transições desordem-ordem na GRASP, sugerindo um comportamento muito distinto quando em condições que imitam a vizinhança da superfície da membrana em comparação com os encontrados quando livre em solução. Outros fatores de enovelamento, tais como o molecular crowding, contra-ions, pH e a fosforilação exibem efeitos menores (ou nenhum) na estrutura secundária e/ou estabilidade da GRASP. Este é o primeiro estudo focado na compreensão das transições desordem-ordem em uma estrutura do tipo glóbulo fundido sem que houvesse a necessidade de qualquer condição desnaturante. Em relação aos PDZs que formam o domínio GRASP, observamos que as GRASPs são formadas por um PDZ1 mais instável e flexível e um PDZ2 muito mais estável e estruturalmente bem comportado. Mais do que isso, muitas das regiões instáveis encontradas no PDZ1 estão no predito bolsão de ligação, sugerindo uma promiscuidade estrutural dentro desse domínio que se correlaciona com a promiscuidade funcional de interação com múltiplos parceiros proteicos. É apresentado nesta tese a primeira caracterização estrutural de uma GRASP em sua forma completa, o primeiro modelo de como as GRASPs (ou qualquer proteína em forma de glóbulo fundido) pode ser modulada estruturalmente pela célula durante diferentes funcionalidades e o primeiro trabalho na comunidade provando que a estabelecido ideia de que ambos os PDZs são estruturalmente equivalentes não é completamente correta
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Adediji, Adekunle C. "PCA Eigen Residuals: An Analytical Solution to System Modeling and Multivariate Structural Health Monitoring." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1377865741.
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Gossis, Kosmas. "Using interior point algorithms for the solution of linear programs with special structural features." Thesis, Aston University, 1995. http://publications.aston.ac.uk/10632/.
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Linear Programming (LP) is a powerful decision making tool extensively used in various economic and engineering activities. In the early stages the success of LP was mainly due to the efficiency of the simplex method. After the appearance of Karmarkar's paper, the focus of most research was shifted to the field of interior point methods. The present work is concerned with investigating and efficiently implementing the latest techniques in this field taking sparsity into account. The performance of these implementations on different classes of LP problems is reported here. The preconditional conjugate gradient method is one of the most powerful tools for the solution of the least square problem, present in every iteration of all interior point methods. The effect of using different preconditioners on a range of problems with various condition numbers is presented. Decomposition algorithms has been one of the main fields of research in linear programming over the last few years. After reviewing the latest decomposition techniques, three promising methods were chosen the implemented. Sparsity is again a consideration and suggestions have been included to allow improvements when solving problems with these methods. Finally, experimental results on randomly generated data are reported and compared with an interior point method. The efficient implementation of the decomposition methods considered in this study requires the solution of quadratic subproblems. A review of recent work on algorithms for convex quadratic was performed. The most promising algorithms are discussed and implemented taking sparsity into account. The related performance of these algorithms on randomly generated separable and non-separable problems is also reported.
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Stanley, Robert Peter. "A structural and spectroscopic investigation of polyfluorene copolymers in solution and the solid state." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14629.
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This thesis involves a structural and spectroscopic investigation of the electroluminescent polymer poly(9,9-dioctylfluorene), F8T2, and its copolymers poly(9,9-dioctyl)fluorene, PFO, and poly(9,9-dioctylfluorene-alt-benzothiadiazole), F8BT. Small angle neutron scattering (SANS) studies have shown that the three polymers take up very rigid, rod-like conformations in toluene and chloroform solutions. Aggregation effects of F8T2 in toluene were studied over 16 hours with a sheet-like aggregate structure suggested. Light-scattering (LS) measurements were used to investigate the molecular weight, backbone conformation on different length scales, coil size and the effect of chain aggregation in different solvents, and at different temperatures of the three polymers. Again, the polymers appear to be very rigid, with precise molecular weights and radii of gyrations found. F8T2 was extensively studied using optical absorption, photoluminescent (PL) emission, PL quantum efficiency (PLQE) and PL lifetime measurements of solutions and films deposited from them. Strong PL quenching effects were seen which have been attributed to interchain interactions at concentrations around 0.01 mg/ml, self-absorption effects dominate at higher concentrations above ~0.1 mg/ml. Large spectral changes were seen due to solvent choice, aggregation effects and thermal dissolution histories. Deposited films were also investigated with temperature dependent PL, which allowed some thermal transition temperatures to be found, atomic force microscopy and as bottom-gate/top-contact organic field-effect transistors. Synchrotron Grazing Incidence Wide-Angle X-ray scattering (GIWAXS) studies were conducted on films deposited on flat substrates and polyimide alignment layers, as well as annealed within an in-situ vapour cell. F8T2 was found to be a poor scatterer of X-rays but F8BT appears to stack with a vertical interchain distance of 4.4 Å, with an interchain seperation of 5.8 Å due to sidechains. Other copolymers of F8T2, poly[2,7-(9,9-dihexylfluorene)-alt-bithiophene] F6T2, and SC005 were found to be good candidates for GIWAXS study. Thermally treated PFO was very well indexed, with clear changes seen due to vapour exposure in situ. Chapter 1 discusses vital, general concepts used to describe electro-conductive polymers, as well as a thorough review of the background of organic semiconductor characterisation. Further relevant details are covered in each results chapter. Chapter 2 describes and defines the polymer samples and processing methods used throughout this thesis. The experimental techniques used are described in detail, as are the polymers involved and sample fabrication methods. In Chapter 3 small-angle neutron scattering undertaken at RAL is discussed, with results shown from F8T2 in various solvents, as well as studies of F8BT and PFO. Chapter 4 covers both the results of multi-angle light scattering on F8T2 and other polyfluorenes in a variety of solvents. The effect of the passage of time of dissolved polymer solutions is investigated, along with size and molecular weight characteristics in different solvents. SAXS results from F8T2 solutions are also briefly discussed. In Chapter 5 a broad variety of spectroscopic investigations of F8T2 are discussed, both in solution and as thin-films. The effects of thermal treatments on thin-films are studied, including DSC results and the consequences on the electrical properties of thermal and solvent annealing on field-effect transistors. In Chapter 6 the results from a GIWAXS study on aligned and non-aligned thin-films of PFO and three co-polymers are shown. Unit cell size parameters are determined, and the effect of exposing PFO thin-films to solvent vapour is studied.
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Winters, Ian Douglas. "The rheological and structural properties of blends of polyethylene with paraffin wax." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45833.
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This research addresses and illuminates a little understood region of miscible polymer mixtures and demonstrates a new means of separating wax from such blends. The method, termed Deformation Induced Phase Segregation potentially eliminates need of toxic processing solvents for wax removal or recovery in these types of blends.
Previous theories of polymer combinations address them exclusively as solutions or as blends, two independent classes having very different behaviors. This study provides bridge connecting these two classes by identifying crossover points between them and the behaviors exhibited therein. The blends of this form were found to be semi-miscible, forming a homogenous phase in the melt but a two-phase system in the solid, with the rheological behavior influenced by the polymer's molecular weight and architecture. It also demonstrates practical promise of this regime by introducing a mechanical compression process to separate the wax phase from such a type of blend. This process potentially permits production of ultra-high molecular weight polyethylene (UHMwPE) films and fibers by melt processing, thereby obviating need of otherwise essential but expensive and environmentally unfriendly toxic solvents.
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Cordier, Florence. "Développements méthodologiques et études dynamiques de protéines en solution par relaxation en RMN." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10090.
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Dans la premiere partie de ce travail, nous avons propose le principe de dimensionalite reduite dans des experiences heteronucleaires multidimensionnelles sur des proteines marquees #1#5n/#1#3c. Deux experiences (3d-mq-hncoca et 3d-mq-noesy doublement filtree #1#5n/#1#5n et/ou #1#5n/#1#3c) utilisant ce principe ont ete mises au point et en ont montre l'interet pour l'attribution et le calcul de structure tridimensionnelle preliminaire. La majeure partie de ce travail concerne l'etude de la dynamique des proteines dans la gamme ps-ms par la mesure de parametres de relaxation. Dans un premier temps, les parametres de relaxation des noyaux #1#5n contenant l'information sur la mobilite des vecteurs n-h du cytochrome c#2 de rhodobacter capsulatus ont ete interpretes en parametres dynamiques grace a l'approche de lipari et szabo. Les mouvements internes sont caracterises par un parametre d'ordre et un temps de correlation interne et sont superposes a un mouvement de reorientation isotrope caracterise par un temps de correlation global. La qualite des parametres dynamiques extraits nous ont incite a considerer un mouvement global anisotrope, caracterise par un tenseur de diffusion d. Celui-ci a pu etre caracterise avec une excellente precision et les parametres de mobilite interne ont pu ensuite etre extraits par cette approche hybride avec une plus grande fiabilite, mettant en evidence la nature relativement compacte de cette proteine meme si une plus grande flexibilite est observee dans certaines boucles. Enfin, l'etude du vecteur ca-co a ete entreprise dans l'optique de caracteriser l'anisotropie des mouvements locaux, a cote de l'information issue du vecteur n-h. Des simulations de dynamique moleculaire ont permis de proposer des modeles de mouvements du plan peptidique pour certains residus et une experience rmn triple-resonance destinee a la mesure de la vitesse de relaxation croisee ca-co a ete mise en place. Ce parametre a finalement pu etre converti en parametre d'ordre.
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Andreotti, Elena. "Study of an alternative structural solution for the new quay of Trattaroli Terminal in Ravenna." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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The thesis developed, aims the entire design for the new quay structure of Trattaroli peninsula in the port of Ravenna. The topic has been developed during a stage, lasting five months, at Sapir Engineering S.r.l. that operates in the field of public and private civil engineering works.
The Port of Ravenna is the main port of Emilia-Romagna region. Docks are mainly on a channel that connects the town centre of Ravenna to the open sea, which is almost 10,00 km away. It hosts shipyards, multipurpose terminals, bulk cargo terminals and a containerized cargo terminal. The study at issue, regards the Candiano Channel, in particular the Trattaroli peninsula, located in the internal part of the Corsini Port that connects the centre of Ravenna with the open sea and is part of the commercial and industrial port.
Specifically, in the thesis, it has been modified the existing project with new technological solutions and using alternative materials for structural and lasting performance improvements. For this reason, some numerical models have been applied to elaborate the study in terms of hydraulic, geotechnical and structural design.
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Toker, Saadet. "Developing An Innovative Architectural And Structural Solution For Seismic Strengthening Of Reinforced Concrete Residential Buildings." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604985/index.pdf.
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The recent earthquakes in Turkey have shown the poor seismic performance of reinforced concrete. This led to widespread utilization of several strengthening methods, each of which is convenient in different aspects. However, what is required to apply any of these methods is to evacuate the building in question since the interruptions are mostly within the building and to the structural members.
This study proposes a method for external strengthening of typical five storey reinforced concrete buildings that represent the majority of the built environment in Turkey. The method suggests addition of shear walls, which are connected to each other by means of diaphragms on two floor levels, to the existing external columns at four corners of the building. The positive effect of shear walls in seismic performance is already knownhowever
basically, the aim of this study is to discuss the feasibility of the proposed method in terms of architectural viewpoint since the method unavoidably covers great modifications on the architectural form of the building. Hence, the research mostly explores whether it is possible to give the reinforced concrete residential buildings, which constitute the majority of the built environment especially after 1950s due to the unhealthy urbanization period in Turkey, a common characteristic appearance by means of external structural members. As a whole, proposing an external strengthening method that provides not to evacuate the space, the study searches to obtain a typical faç
ade resemblance by means of additional structural members.
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Faure, Delphine. "Polymorphisme structural d'agrégats en solution : conception, synthèses et études physico-chimiques d'amphiphiles de type azobenzène." Bordeaux 1, 2004. http://www.theses.fr/2004BOR12866.
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La plupart des modèles amphiphiles connues sont des savons et des phospholipides, composés d'une partie polaire hydrophile, généralement courte et volumineuse et d'une partie hydrophobe composée d'une ou deux chaînes d'hydrocarbonées. Dans l'eau, c'est l'effet hydrophobe qui permet l'agrégation de ces molécules amphiphiles en une grande variété de morphologies différentes (micelles, vésicules, etc. ). Un certain nombre de paramètres jouent un rôle dans la détermination de la coubure de l'interface lipide-eau ainsi que le passage d'une morphologie à une autre. Dans notre étude nous avons synthétisé des molécules amphiphiles contenant un groupe photo-ajustable dérivé d'azobenzène. La variation conformationelle provoquée par l'isométrie photoinduite Z-E induit une grande variation dans les morphologies observées. Nous avons montré que des amphiphiles gemini cationiques qui possèdent un espaceur azobenzene changent de conformation à l'interface eau-air, et nous permettent de moduler la pression de surface en utilisant un stimulus externe, à savoir l'irradiation UV. En solution, ces molécules forment spontanément des vésicules poly-dispersent qui, préparées en présence d'une petite quantité de CTAB se rompent sous irradiation UV. Nous avons également montré qu'il existait une interaction entre l'ADN et les gimini cationique et zwiterrionique.
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MANDALITI, WALTER. "The role of structural determinants on the biological functions in the peptide-membrane and protein-protein interactions: the solution structure approach." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2016. http://hdl.handle.net/2108/201789.
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NMR spectroscopy in many of the more recent applications can give relevant information in the study of biomolecular structure and about their interactions. The results of the studies here reported show that in the case of the peptide –membrane and protein –protein interactions NMR spectroscopy often may give many informations about the structural details of the interaction. These results are useful to understand better the mechanism of the intermolecular recognition and/or the conformational change(s) upon binding. In the study of Thymosin α1, a hormone peptide whose specific cellular receptor(s) were not found, Circular Dichroism and NMR spectroscopy techniques revealed that a conformational change of this biomolecule toward a structured form upon interaction with membrane model and cell occurs. Particularly a preference of this hormone was found for phosphatidylserine exposed on membrane surface. The hypothesis that the biological mechanism of action of this hormone may consist in a membrane catalyzed interaction seems valid and this hypothesis may give information about future medical applications in other pathologies. In the study of the proteic domain CUBAN and of its interaction with the ubiquitin-like protein NEDD8 the solution structure of the protein and of its complex has been elucidated. The results obtained by NMR spectroscopy are in agreement with the results of pull-down and mutagenesis experiments. By the observation of the chemical shift perturbations of the 15N HSQC spectra upon addition of proteins revealed the possibility of he existence of an early stage in the interaction. A complex interplay between hydrophobic and polar interactions, driven by structural determinants of the two proteins, was found to be the driving force of the recognition mechanism. The studies reported in this Ph.D thesys were performed in collaboration with two different groups of University of Rome “Tor Vergata”. The elucidation of the interaction of Thymosin-alpha1 with model membranes and cells were performed in collaboration with proff. E. Garaci, P. Sinabaldi Vallebona and F. Pica. The structural investigation of CUBAN domain of KHNYN and the studies of its interaction with NEDD8 protein were developed with the collaboration of doc. E. Santonico and prof. G. Cesrani’s group.
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Singh, P. B. "Structural and functional studies on classical class I transplantation antigens in solution in the body fluids." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383951.
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Stopford, Andrew Paul. "Structural and thermodynamic analysis of peptide and protein ions in solution and in the gas phase." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/14493.
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The following thesis details the structural and thermo-dynamic analysis of melittin, mutant tryptophan cage constructs and a series of truncated murine β-defensin 14 derivatives in solution, in vacuo and in silico. These experiments are used to identify correlations between their solvated and desolvated structural isoforms and, in doing so, investigate the role of mass spectrometry in the field of structural proteomics. The integrated experimental approach described in this thesis employs an array of analytical techniques including charge partition calculations, capillary-induced thermal degradation, gas phase hydrogen/deuterium exchange and collision induced dissociation to obtain a consensus view of the structural organisation of each analyte. Supporting evidence is presented from antimicrobial assays, molecular modelling and dynamics calculations, circular dichroism and fluorescence spectroscopy and ion mobility mass spectrometry. In addition, a novel gas inlet system is detailed which allows gas phase ion/molecule reactions, such as hydrogen/deuterium exchange, to be performed within the quadrupole ion traps of a Finnigan LCQ Classic. Significant differences are observed between the solvated and desolvated structures of most of the analyte ions examined, unless they exhibit a very stable structural fold. This suggests an important role for mass spectrometry in the field of structural proteomics, but, one that is limited to the comparative study of different solvation states, the analysis of biologically important membrane interactions and the analysis of peptides and proteins that are expressed or secreted into hydrophobic environments.
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Hallworth, Georgina Louise. "Exploring the influence of structural variation on the solution and solid-state behaviour of cyanine dyes." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/72960/.
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Cyanine dyes are well known and extensively studied molecules. The preparations and investigations of a wide range of dyes have been previously reported. Here several novel and known compounds have been synthesised to investigate the effect molecular structure has on their bulk-solution and solid-state behaviour. The preparations of sulfur-containing tri- and monomethine dyes were more reliable, hence the majority of these studies concerned sulfur analogues. Successful crystallisation of these products resulted in many novel crystal structures being obtained and compared. The monomethine dyes provided a simple, systematic study which could be analysed revealing relationships between the structures. The trimethine x-ray structural studies were less systematic but more varied. Despite many more structures being required, it appears that the prediction of packing structures may be possible from the molecular structure. In aqueous solution cyanine dyes are known to form supramolecular-type aggregates with and without the presence of inorganic salts. The aggregation process of several trimethine dyes was found to be accelerated by the anion of inorganic salts with di- and trivalent anions being more efficient than monovalent anions. Simple oxygen containing dyes were found not to aggregate even in the presence of salts, this suggests that the heteroatom has a crucial role in the aggregation process. The aggregation process was affected by molecular structure but these effects were not noticeable when concerned with the fluorescence yield. Electronic Lab Notebooks (ELN) have become successful in commercial companies but less so in academia. An ELN package designed primarily for use in a university research environment has been newly developed. This project involved trailing this product to test the system and provide feedback about the use. Several issues were recognized to affect the way the package functioned, but areas where improvements could be made were identified.
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Kateb, Fatiha. "Developement and applications of NMR methodologies to structural and dynamical studies of biological macromolecules in solution." Paris 6, 2007. http://www.theses.fr/2007PA066033.
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La caractérisation de la structure et de la dynamique de biomolécules par RMN représente un grand enjeu dans l’étude de systèmes biologiques. Le développement de méthodes complémentaires à l’étude classique en RMN, telles que l’étude des fluctuations concertées des déplacements chimiques isotropes nous a permis de caractériser la présence de mouvements lents dans un système biologique pertinent : un complexe de centrine humaine avec un peptide cible. Par ailleurs, les phénomènes d’interférence impliquant un centre paramagnétique constituent, aujourd’hui, un outil puissant pour obtenir de nouvelles contraintes dans le cadre d’études structurales de macromolécules biologiques. Cette approche a été appliquée au même système dans lequel un ion Ca2+ a été remplacé par un ion paramagnetique. Enfin, nous avons développé une nouvelle méthode grâce à laquelle nous avons pu mesurer des vitesses d’échange de protons avec le solvant atteignant les 105 s-1. Nous avons pu ainsi déterminer les vitesses d’échange du proton indole du tryptophane dans ses formes cationique, zwitterionique, et anionique.
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Kang, Chiwon Kim Dong Joo. "Structural and electrical characterization of highly oriented (KxNax)NbO3 (KNN) thin films by chemical solution deposition." Auburn, Ala, 2009. http://hdl.handle.net/10415/1604.
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Darwiche, Mostafa. "When operations research meets structural pattern recognition : on the solution of error-tolerant graph matching problems." Thesis, Tours, 2018. http://www.theses.fr/2018TOUR4022/document.
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Cette thèse se situe à l’intersection de deux domaines de recherche scientifique la Reconnaissance d’Objets Structurels (ROS) et la Recherche Opérationnelle (RO). Le premier consiste à rendre la machine plus intelligente et à reconnaître les objets, en particulier ceux basés sur les graphes. Alors que le second se focalise sur la résolution de problèmes d’optimisation combinatoire difficiles. L’idée principale de cette thèse est de combiner les connaissances de ces deux domaines. Parmi les problèmes difficiles existants en ROS, le problème de la distance d’édition entre graphes (DEG) a été sélectionné comme le cœur de ce travail. Les contributions portent sur la conception de méthodes adoptées du domaine RO pour la résolution du problème de DEG. Explicitement, des nouveaux modèles linéaires en nombre entiers et des matheuristiques ont été développé à cet effet et de très bons résultats ont été obtenus par rapport à des approches existantesThis thesis is focused on Graph Matching (GM) problems and in particular the Graph Edit Distance (GED) problems. There is a growing interest in these problems due to their numerous applications in different research domains, e.g. biology, chemistry, computer vision, etc. However, these problems are known to be complex and hard to solve, as the GED is a NP-hard problem. The main objectives sought in this thesis, are to develop methods for solving GED problems to optimality and/or heuristically. Operations Research (OR) field offers a wide range of exact and heuristic algorithms that have accomplished very good results when solving optimization problems. So, basically all the contributions presented in thesis are methods inspired from OR field. The exact methods are designed based on deep analysis and understanding of the problem, and are presented as Mixed Integer Linear Program (MILP) formulations. The proposed heuristic approaches are adapted versions of existing MILP-based heuristics (also known as matheuristics), by considering problem-dependent information to improve their performances and accuracy
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Perras, Frédéric Alain. "Structural Insights from the NMR Spectroscopy of Quadrupolar Nuclei: Exploiting Electric Field Gradient and Spin-Spin Coupling Tensors." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31883.
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NMR spectroscopy has evolved into one of the most important characterization techniques in chemistry with which it is possible to obtain valuable structural, dynamical, and mechanistic information. Most applications of NMR have however been limited to the use of nuclei having spin quantum numbers of 1/2. This thesis discusses the developments that have been advanced in order to extract quantitative structural information from the NMR spectroscopy of quadrupolar nuclei (spin, I>1/2) which account for the vast majority of the NMR-active nuclei. In a first part of the thesis, a NMR crystallographic method is developed which uses the electric field gradient tensor measured at the nuclear sites as an experimental constraint in DFT-based crystal structure refinements. This inclusion of experimental data into crystal structure refinements enables the determination of higher quality, and experimentally-relevant, structures. We apply this new methodology in order to determine higher quality crystal structures for the non-linear optical material Na2B2Al2O7, sodium pyrophosphates, and the near-zero thermal expansion material ZrMgMo3O12. In a second part of this thesis, experimental techniques are developed for the measurement of spin-spin coupling between pairs of quadrupolar nuclei; the measurement of spin-spin coupling carries with it extremely valuable distance and connectivity information. Using DOR NMR, heteronuclear residual dipolar coupling as well as homonuclear J coupling multiplets can be observed. Notably, the J coupling between quadrupolar nuclei can still be measured in A2 spin systems, unlike in the case of pairs of spin-1/2 nuclei. The theory that was developed for the characterization of these multiplets was extended for the general simulation of exact NMR spectra of quadrupolar. This program, known as QUEST, is now free to use by anyone in the scientific community. Pulsed J-resolved NMR experiments are then described which enable the facile measurement of J and dipolar coupling in homonuclear pairs of quadrupolar nuclei. Notably, the J splitting is greatly amplified in A2 spin systems which provides strong structural information and enables the precise detection of smaller J coupling constants. These techniques are applied towards directly studying gallium metal-metal bonding interactions as well as boron-boron bonds in diboron compounds of importance in β-boration chemistry.
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Lorenz, Charlotte [Verfasser], Walter [Akademischer Betreuer] Richtering, and Christian [Akademischer Betreuer] Herrmann. "Structural investigation of the human Guanylate Binding Protein 1 in solution / Charlotte Lorenz ; Walter Richtering, Christian Herrmann." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1194066909/34.
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Lülf, Fritz Adrian. "An integrated method for the transient solution of reduced order models of geometrically nonlinear structural dynamic systems." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2013. http://tel.archives-ouvertes.fr/tel-00957455.
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For repeated transient solutions of geometrically nonlinear structures the numerical effort often poses a major obstacle. Thus, the introduction of a reduced order model, which takes the nonlinear effects into account and accelerates the calculations considerably, is often necessary.This work yields a method that allows for rapid, accurate and parameterisable solutions by means of a reduced model of the original structure. The structure is discretised and its dynamic equilibrium described by a matrix equation. The projection on a reduced basis is introduced to obtain the reduced model. A comprehensive numerical study on several common reduced bases shows that the simple introduction of a constant basis is not sufficient to account for the nonlinear behaviour. Three requirements for an rapid, accurate and parameterisable solution are derived. The solution algorithm has to take into account the nonlinear evolution of the solution, the solution has to be independent of the nonlinear finite element terms and the basis has to be adapted to external parameters.Three approaches are provided, each responding to one requirement. These approaches are assembled to the integrated method. The approaches are the update and augmentation of the basis, the polynomial formulation of the nonlinear terms and the interpolation of the basis. A Newmark-type time-marching algorithm provides the frame of the integrated method. The application of the integrated method on test-cases with geometrically nonlinear finite elements confirms that this method leads to the initial aim of a rapid, accurate and parameterisable transient solution.
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Singh, Jai, O. N. Srivastava, R. S. Tiwari, and P. Kumar. "Structural and optical investigations of low temperature solution based synthesized ZnO and Ag admix ZnO nanoparticles (NPs)." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20574.
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Corcoran, Joseph Michael. "An Energy Diffusion Model for Interior Acoustics with Structural Coupling Using the Laplace Transform Boundary Element Solution." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51793.
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Knowledge of the indoor propagation of sound has many important applications including acoustic prediction in homes, office buildings, stores, and schools, and the design of concert halls, auditoriums, classrooms, and factories. At low frequencies, interior acoustics are analyzed with the wave equation, but significant computational expense imposes an upper frequency limit. Thus, energy methods are often sought for high frequency analysis. However, conventional energy methods are significantly limited by vast simplifications or computational costs. Therefore, new improvements are still being sought.
The basis of this dissertation is a recently developed mathematical model for interior acoustics known as the acoustic diffusion model. The model extends statistical methods in high frequency acoustics to predict the spatial distribution of acoustic energy in the volume over time as a diffusion process. Previously, solutions to the acoustic diffusion model have been limited to one dimensional (1-D) analytical solutions and to the use of the finite element method (FEM).
This dissertation focuses on a new, efficient method for solving the acoustic diffusion model based on a boundary element method (BEM) solution using the Laplace transform. First, a Laplace domain solution to the diffusion model is obtained using the BEM. Then, a numerical inverse Laplace transform is used to efficiently compute the time domain response. The diffusion boundary element-Laplace transform solution (BE-LTS) is validated through comparisons with Sabine theory, ray tracing, and a diffusion FEM solution. All methods demonstrate excellent agreement for three increasingly complex acoustic volumes and the computational efficiency of the BE-LTS is exposed.
Structural coupling is then incorporated in the diffusion BE-LTS using two methods. First, a simple transmission coefficient separating two acoustic volumes is implemented. Second, a structural power flow model represents the coupling partition separating acoustic volumes. The validation of these methods is successfully performed in an example through comparisons with statistical theory, a diffusion FEM solution, ray tracing, and experimental data.
Finally, the diffusion model and the BE-LTS are shown to possess capabilities beyond that of room acoustics. The acoustic transmission through a heat exchanger, acoustic foam, and mufflers is successfully modeled using the diffusion BE-LTS and compared to experimental data.Ph. D.
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Tran, Anh-Tuyet Thi. "Solution ¹H NMR studies on structural and dynamic properties of the R-state cyanomet human adult hemoglobin /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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