When creating a muffler to be installed on a noise generating machine, the design parameters as well as the placements of sound attenuating elements has to be optimized in order to minimize the sound coming out of the equipage. This is exemplified in a small project task for students of a basic course in optimization at KTH. The task is however flawed, since both the way in which the optimization problem is formed is overly simplistic and the algorithm used to solve the problem, fmincon, does not cope well with the mathematical complexity of the model, meaning it gets stuck in a local optimum that is not a global optimum. This thesis is about investigating how to solve both of these problems. The model is modified to combine several frequencies and adjusting them to the sensitivity to different frequencies in the human ear. By doing this, the objective is changed from the previous way of maximizing Dynamic Insertion Loss Dilfor a specific frequency to minimize the total perceived sound level LA.  The model is based on the modular design of TMM from four-pole theory. This divides the muffler into separate parts, with the sound attenuating elements being mathematically defined only by what T matrix it has. The element types to choose from are the Expansion Chamber, the Quarter Wave Resonator and the Helmholtz Resonator. The global optimization methods to choose from are Global Search, MultiStart, Genetic Algorithm, Pattern Search and Simulated Annealing. By combining the different types of sound attenuating elements in every way and solving each case with every global optimization method, the best combination to implement to the model is chosen. The choice is two Quarter Wave Resonators being solved by MultiStart, which provides satisfactory results. Further analysis is done to ensure the robustness of chosen implementation, which does not reveal any significant flaws. The purpose of this thesis is fulfilled. / När man skapar en ljuddämpare som ska installeras på en ljud-genererande maskin bör designparametrarna samt placeringarna av ljuddämpande element optimeras för att minimera ljudet som kommer ut ur ekipaget. Detta exemplifieras i en liten projektuppgift för studenter till en grundkurs i optimering på KTH. Uppgiften är dock bristfällig, eftersom både det sätt som optimeringsproblemet är utformat är alltför förenklat och den algoritm som används för att lösa problemet, fmincon, inte klarar av modellens matematiska komplexitet bra, vilket menas med att den fastnar i ett lokalt optimum som inte är ett globalt optimum. Detta examensarbete handlar om att undersöka hur man kan lösa båda dessa problem. Modellen är modifierad för att kombinera flera frekvenser och anpassa dem till känsligheten för olika frekvenser i det mänskliga örat. Genom att göra detta är målet ändrat från det tidigare sättet att maximera den dynamiska insatsisoleringen DIL för en specifik frekvens till att minimera den totala upplevda ljudnivån LA. Modellen bygger på den modulära designen av TMM från 4-polsteori. Detta delar upp ljuddämparen i separata delar, med ljuddämpande element som matematiskt endast definieras av vilken T matris de har. De elementtyper att välja mellan är expansionskammare, kvartsvågsresonator och Helmholtzresonator. De globala optimeringsmetoder att välja mellan är Global Search, MultiStart, Genetic Algorithm, Pattern Search och Simulated Annealing. Genom att kombinera de olika typerna av ljuddämpande element på alla sätt och lösa varje fall med varje global optimeringsmetod, blir den bästa kombinationen vald och implementerad i modellen. Valet är två kvartsvågsresonatorer som löses genom MultiStart, vilket ger tillfredsställande resultat. Ytterligare analyser görs för att säkerställa robustheten av den valda implementationen, som inte avslöjar några väsentliga brister. Syftet med detta examensarbete är uppfyllt.

This thesis aims to investigate the acoustic properties of ultrasound contrast agents (UCAs) at high ultrasound frequencies. In recent years, there has been increasing development in the use of high frequency ultrasound in the fields of preclinical, intravascular, ophthalmology and superficial tissue imaging. Although research studying the acoustic response of UCAs at low diagnostic ultrasonic frequencies has been well documented, quantitative information on the acoustical properties of UCAs at high ultrasonic frequencies is limited. In this thesis, acoustical characterisation of three UCAs was performed using a preclinical ultrasound scanner (Vevo 770, VisualSonics Inc., Canada). Initially the acoustical characterisation of five high frequency transducers was measured using a membrane hydrophone with an active element of 0.2 mm in diameter to quantify the transmitting frequencies, pressures and spatial beam profiles of each of the transducers. Using these transducers and development of appropriate software, high frequency acoustical characterisation (speed and attenuation) of an agar-based tissue mimicking material (TMM) was performed using a broadband substitution technique. The results from this study showed that the acoustical attenuation of TMM varied nonlinearly with frequency and the speed of sound was approximately constant 1548m·s-1 in the frequency range 12-47MHz. The acoustical properties of three commercially available lipid encapsulated UCAs including two clinical UCAs Definity (Lantheus Medical Imaging, USA) and SonoVue (Bracco, Italy) and one preclinical UCAs MicroMarker (untargeted) (VisualSonics, Canada) were studied using the software and techniques developed for TMM characterisation. Attenuation, contrast-to-tissue ratio (CTR) and subharmonic to fundamental ratio were measured at low acoustic pressures. The results showed that large off-resonance and resonant MBs predominantly contributed to the fundamental response and MBs which resonated at half of the driven frequency predominantly contributed to subharmonic response. The effect of needle gauge, temperature and injection rate on the size distribution and acoustic properties of Definity and SonoVue was measured and was found to have significant impacts. Acoustic characterisations of both TMM and UCAs in this thesis extend our understanding from low frequency to high frequency ultrasound and will enable the further development of ultrasound imaging techniques and UCAs design specifically for high frequency ultrasound applications.

The underlying theory of “Spin” of an electron and its associated inter-actions causing internal fields and spectral shift to bulk-magnetism iswell established now. Our understanding of spin properties is significant andmore useful than ever before. In recent years there seems to be an enormousinterest towards application oriented materials that harness those spin prop-erties. Theoretical simulations remain in a position to “assist or pilot” theexperimental discovery of new materials.In this work, we have outlined available methodologies for spin coupling inmulti-reference and DFT techniques. We have benchmarked multi-referencespin-Hamiltonian computation in isoelectronic diradicals - Trimethylenemethane(TMM) and Oxyallyl. Also with DFT, parameters are predicted with anewly discovered TMM-like stable diradicals, reported to have large positiveexchange interactions. Excellent agreement were obtained and our findingsemphasize that the dipole-dipole interactions alone can predict the splittingof triplet states and that DFT spin procedures hold well in organic species.We have extended our spin-studies to a highly application oriented ma-terial - nanographene. Using our novel spin-parameter arguments we haveexplained the magnetism of graphene. Our studies highlight a few signifi-cant aspects - first there seems to be a size dependency with respect to thespin-Hamiltonian; second, there is a negligible contribution of spin-orbit cou-pling in these systems; third, we give a theoretical account of spin restrictedand unrestricted schemes for the DFT method and their consequences forthe spin and spatial symmetry of the molecules; and, finally, we highlightthe importance of impurities and defects for magnetism in graphene. Wepredict triplet-singlet transitions through linear response TDDFT for thetris(8-hydroxyquinoline) aluminium complex, an organic molecule shown tohave spintronics applications in recent experiments. Our spin studies werein line with those observations and could help to understand the role of thespin-coupling phenomena. / QC 20120531

The thesis discusses the fiber Bragg gratings simulations, analysis and design. In the present time, there are several methods to simulate fiber gratings response based on the stated parameters that define their dimensions and material features. However, this work deals with a different issue, that is the synthesis of the input parameters for demanded spectral responses. The main aim of the work is to achieve a synthesis method that would help to discover parameters describing advanced grating structure, based on the required spectral reflectivity. The basic demand for the parameter synthesis is an achievement of the real values in terms of the consequent production of the suggested structure. The described synthesis method considers advanced fiber grating structure as a structure of several uniform grating sections. The input parameters are estimated in steps, using the well-known direct methods in order to obtain grating responses and feedback to establish the parameters changes. The principle methods involve establishment of initial input parameter values and necessary subsequent algorithm leading to optimize the required spectral response. The initial values are calculated by a simplified model based on the coupled theory equations that are handled for the periodic disturbances in cylindrical waveguide. The following optimization uses the multiple thin film stack and transfer matrix methods. The properties of grating structure spectral reflectivity are step by step calculated while using these direct methods. Input parameters are established in the next several steps. Establishment of input parameters is done subsequently, based on the demanded and calculated output spectral reflectivity properties. Optimizing process is limited by possibilities of the grating manufacture technology. It is possible to assemble arbitrary fiber grating structure taking in term the demanded spectral response. Nevertheless, the calculated input parameters are real for the following manufacture. This method could be used to design optical band stop filter, high-pass and low-pass filters or filters for special applications.

[pt] O trabalho apresenta um modelo de ensino de métodos de projeto de produto elaborado de modo a facilitar o trabalho docente nas disciplinas de metodologia de projeto e projeto de produto. A pesquisa vem ao encontro da necessidade de, durante o processo projetual, lidar com vários saberes que deverão estar presentes não apenas na fase de projeto abstrato, como também na concretização do objeto. Sustenta-se na investigação que cabe ao docente ser um facilitador da aprendizagem do futuro designer, demonstrando conhecimento profundo da disciplina a ser ministrada, de forma a ressaltar seus aspectos fundamentais e esclarecer acerca de suas aplicações práticas. O aporte teórico do trabalho mostra que a atividade cientifica do design, que estuda métodos e determina a lógica e processos sequenciais se mostra adequada para tornar o design uma prática reflexiva. Entre as habilidades e competências, o designer deve ter capacidade criativa para propor soluções inovadoras, utilizando-se do domínio de técnicas e do processo de criação, assim como domínio das diferentes etapas do desenvolvimento de um projeto, a saber: definição de objetivos, técnicas de coleta e análise de dados, geração e avaliação de alternativas, configuração de solução e comunicação de resultados. As duas habilidades e competências são básicas, pois é isso que se deseja do formando. Assim, o ensino de design deve ser de qualidade e os conhecimentos de métodos projetuais devem ser apreendidos pelo futuro designer para que possa exercer a sua profissão com segurança. O método não garante a solução nem a eficácia do projeto e da sua concretização, pois está relacionado à aproximação com os saberes sendo apenas uma garantia de consecução da finalidade. Dessa forma, o trabalho aqui apresentado tem como objetivo propor o Modelo de Ensino de Métodos de Design de Produto (MEM), apoiado na teoria da aprendizagem significativa. O MEM visa que o professor use estratégias diferenciadas para alcançar a aprendizagem significativa, a partir de um guia que se apóia nos conhecimentos da pedagogia por meio da metodologia do ensino superior. O trabalho propõe estratégias de aprendizagem, estratégias de avaliação e recursos como instrumentos capazes de proporcionar uma aprendizagem mais eficaz de 40 métodos de projeto de produto. Finalmente, o trabalho apresenta a aplicação do MEM pelo período de um semestre na disciplina de Metodologia de Projeto da Univille. A partir dos resultados da avaliação conclui-se sobre a eficácia do modelo, recomendando-se seu uso por outros docentes das disciplinas de Metodologia de Projeto e Projeto de Produto em cursos de design. / [en] This study presents a teaching model for product design methods. It was developed in order to assist the teacher in subjects such as Project Methodology and Product Design. The research aims to attend the necessity, during the product design process, in dealing with all kind of information to be considered not only during the abstract project phase, but also at the moment of the project achievement. During the study the author affirms that the teacher should be a facilitator in the learning process of the future designer, while showing thorough knowledge of the subject to be taught, in a way to emphasize its fundamental aspects and enlighten its practical applications. The theoretical contribution of this study shows that the scientific activity of design, which investigates methods and determines the logic and sequential processes, has demonstrated to be suitable to transform design into a reflective practice. Beyond abilities and competence, a designer should possess creative capacities in order to propose innovative solutions, by means of mastery of the process designing techniques, as well as mastery of the different development steps of a project, namely: object definition, data collection and data analysis techniques, generation and evaluation of alternatives, solution configuration and communication of the results. These two abilities and competences are fundamental, and are required of a graduate student. Therefore, education in design should possess quality and the knowledge regarding project design methods should be learned by the future designer so he or she will be able to face his profession with confidence. This method neither guarantees the solution nor the project’s effectiveness and its achievement since it is related to the approximation of knowledge, being only a guarantee of the attainment of the project s aim. Thus, this study aims to propose a Teaching Model for Product Design Methods (TMM), based on the theory of meaningful learning. The method proposes that the teacher should use differentiated strategies to achieve meaningful learning, based on a guide, which relies on pedagogic knowledge by means of the methodologies of higher education. This study proposes learning strategies, evaluation strategies and 40 product design methods as tools capable of providing a more effective learning process. At last, this work presents the application of the method to the subject Project Methodology during a semester at the Univille University and from the analysis of the results, the effectiveness of the model is found, thus recommending its use by other teachers of the subjects Project Methodology and Project Design of industrial design courses.

Many applications of ultrasound test phantoms require that the acoustical properties of the phantom should closely match those of soft tissue. Numerous commercial test phantoms of this type are available for use with clinical ultrasound scanners, which use frequencies up to 20 MHz. However, scanners designed for imaging small animals in preclinical studies, typically operate at much higher frequencies. No commercially available test phantoms exist for use at frequencies above 20 MHz. The aim of this work was to develop a tissue-mimicking-material (TMM) that closely matches the acoustic properties of small animal tissues at high frequencies (HF). Such a material would, therefore, be suitable for ultrasound test phantoms for application with HF ultrasound scanners (20 MHz to 50 MHz). A three-step approach was adopted to address this lack of a suitable HF-TMM. Firstly, verify the acoustic characteristics of the existing IEC agar-based TMM. Secondly, establish the acoustic properties (speed of sound and attenuation coefficient) of small animal tissue at high frequencies. Thirdly, develop a TMM which exhibits, as closely as possible, these small animal tissue acoustic characteristics. A pulse-echo substitution method was used throughout to characterise the materials and the tissue samples. The speed of sound and attenuation coefficient of an IEC agar-based TMM were measured using two different techniques. Initially, a widely used method was tried, where samples are wrapped in film and placed in degassed, deionised water for assessment. The second technique was developed and validated for use in this work. In this method, TMM samples were uncovered (without film) and were both stored and assessed in a TMM preserving fluid. The second method provided up to four times more consistent results. The acoustical properties of the individual components of the IEC agar-based TMM were then measured in order to determine whether the overall attenuation coefficient of the agar TMM was a linear sum of the attenuation coefficients of its component parts. Within experimental uncertainties, this was found to be the case. This is a key observation from which the formulation of an agar TMM, matching the acoustic properties of small animal tissue, can be facilitated. The acoustical properties (speed of sound and attenuation coefficient) of mouse brain, liver, and kidney were measured using a preclinical ultrasound scanner.

No description available.

<p>Intake and Exhaust system noise makes a huge contribution to the interior and exterior noise of automobiles. There are a number of linear acoustic tools developed by institutions and industries to predict the acoustic properties of intake and exhaust systems. The present project discusses and validates, through measurements, the proper modelling of these systems using BOOST-SID and discusses the ideas to properly convert a geometrical model of an exhaust muffler to an acoustic model. The various elements and their properties are also discussed.</p><p>When it comes to Acoustic properties there are several parameters that describe the performance of a muffler, the Transmission Loss (TL) can be useful to check the validity of a mathematical model but when we want to predict the actual acoustic behavior of a component after it is installed in a system and subjected to operating conditions then we have to determine other properties like Attenuation, Insertion loss etc,.</p><p>Zero flow and Mean flow (M=0.12) measurements of these properties were carried out for mufflers ranging from simple expansion chambers to complex geometry using two approaches 1) Two Load technique 2) Two Source location technique. For both these cases, the measured transmission losses were compared to those obtained from BOOST-SID models.</p><p>The measured acoustic properties compared well with the simulated model for almost all the cases.</p>

L’émergence de la résistance à une multitude d’agents antimicrobiens chez des bactéries pathogènes est considérée comme une menace majeure pour la santé publique (2). Ces souches sont reconnues comme des organismes multirésistants aux médicaments ou MDR (multidrug-resistant) (4). Les recherches progressent chez les bactéries, à Gram positif, à Gram négatif et acido-alcoolo-résistantes au vu de l’ampleur de la menace pour la santé publique, ces bactéries multirésistantes sont devenues les cibles potentielles à cette fin de recherche. De ce fait, les objectifs de la présente étude ont consisté en la caractérisation structurale et fonctionnelle de différents transporteurs transmembranaires de la famille des RND (Resistance-Nodulation-Division) encore énigmatiques, à savoir: le MmpL3 chez Mycobacterium tuberculosis (Mtb) via l’étude de son orthologue CmpL1 chez Corynebacterium glutamicum (Cgl) et le TriAxBC chez Pseudomonas aeruginosa (P. aeruginosa). Ainsi, comme première démarche présentée dans le chapitre 2, la structure du transporteur MmpL3 Mtb (un transporteur d'acides mycoliques – sous forme de tréhalose de monomycolates (ou TMM) - essentiel pour la viabilité de Mtb) (5) et celle de son orthologue CmpL1 Cgl ont été prédites via le serveur I-TASSER (6-8). Ces structures ont été validées par la suite en comparant à la carte électronique générée pour CmpL1 (18 Å) par des analyses de microscopie électronique en transmission à coloration négative (TEM). La caractérisation du transporteur CmpL1 purifié par chromatographie à exclusion stérique a confirmé le complexe trimérique de taille avoisinant les 315 KDa (incluant la couronne du détergent) en accord avec des analyses par gel SDS-PAGE. Des études génétiques et biochimiques en collaboration ont d’autre part identifié des résidus engagés dans le transport du TMM chez MmpL3 ainsi que d’autres impliqués dans la résistance à des inhibiteurs ciblant ce transporteur. L’ensemble de ces données a mis en évidence la localisation des résidus essentiels au transport et à la résistance au niveau du canal central du modèle trimérique de MmpL3. La région de MmpL3 activant le transport par force protomotrice a été localisée au niveau d’une cavité centrale qui est une caractéristique intrinsèque de la famille des RND. Les cartes électroniques de faible résolution déjà obtenues pour la protéine CmpL1 font de ce projet une des directions futures du laboratoire. Dans le chapitre 3, nous illustrons le deuxième aspect du présent projet qui repose sur l’extension de l’étude du potentiel thérapeutique du ciblage du transporteur transmembranaire MmpL3 chez les différentes souches de Mycobacterium. Nos collaborateurs ont effectué une analyse biochimique de l’effet thérapeutique des inhibiteurs les plus prometteurs du transporteur MmpL3 Mtb sur certaines souches mycobactériennes non-tuberculeuses (NTB) multi-résistantes. Basés sur nos modélisations structurales comparatives obtenues par I-TASSER (6-8), nous avons pu complémenter les informations biochimiques en soulignant les similitudes et les différences de structure entre les souches TB et NTB ainsi que leurs impacts fonctionnels. Ce chapitre met en évidence l’intérêt du ciblage thérapeutique de MmpL3 chez les espèces NTB. En effet, l’efficacité de certains inhibiteurs de MmpL3 Mtb sélectionnés sur le traitement des infections pulmonaires NTB promet de pouvoir généraliser cette nouvelle voie de traitement pour d’autres souches multi-résistantes NTB voire à contribuer à remédier à la problématique de la résistance aux antibiotiques et décomplexifier le traitement actuel. D’autres études en collaboration entreprenant les mêmes approches d’études structurales ont été réalisées pour les transporteurs tripartites TriAxBC (P. aeruginosa), des pompes à efflux appartenant à la famille des RND. Le but du chapitre 4 était de générer une structure du complexe et de déchiffrer son mode d’assemblage et d’expulsion des antibiotiques vers le milieu externe. Un modèle à structure quaternaire de TriAxBC a été prédit par I-TASSER (6-8) et validé contre sa carte électronique à 4.3 Å générée en Cryo-EM. Le complexe TriAxBC a été également caractérisé par filtration sur gel confirmant une taille approximative de 620 KDa et sa composition en trimère par visualisation sur gel SDS-PAGE. En conclusion, nous avons pu à travers cette étude combiner différentes approches biochimiques, génétiques et structurales soutenant la nécessité d’une approche multidisciplinaire pour l’approfondissement de la compréhension de la structure et du mode de fonctionnement des transporteurs RND. Ces derniers demeurent toujours énigmatiques; toutefois, nos avancées et d’autres à venir permettront la génération de nouveaux médicaments spécifiques traitant les bactéries multirésistantes. / The emergence of resistance to a multitude of antimicrobial agents in pathogenic bacteria is considered a major threat to public health (2). These strains are recognized as multidrug resistant organisms (MDR) (4). Research is progressing in Gram positive, Gram positive high GC and Gram negative bacteria, and given the scale of the public health threat, these MDR have become potential targets for this research. The objectives of the present study consist of the structural and functional characterization of various transmembrane transporters of the still enigmatic RND (Resistance-Nodulation-Division) family, namely: MmpL3 in Mycobacterium tuberculosis (Mtb) via the study of its ortholog CmpL1 in Corynebacterium glutamicum (Cgl) and TriAxBC in Pseudomonas aeruginosa (P. aeruginosa). The first component of this project, presented in Chapter 2, studies the structure of the transporter MmpL3 Mtb (a TMM mycolic acid transporter essential for the viability of Mtb (5) and that of its CmpL1 Cgl orthologue, which have been predicted via the I- Tasser Pack (6-8). These structures were subsequently validated by comparing to the electronic map generated for CmpL1 (18 Å) by negative staining transmission electron microscopy (TEM). Characterization of the purified CmpL1 transporter by size exclusion chromatography confirmed the trimeric complex size around 315 KDa (including the detergent crown) corroborated by SDS-PAGE gel analyses. Collaborative genetic and biochemical studies have also identified residues involved in the transport of TMM in MmpL3 as well as those residues conferring antibiotic resistance. This data highlighted the location of the essential residues of transport and resistance in the central channel of the trimeric Mmpl3 model. The MmpL3 region activating proto-motor transport has been located at a central cavity, which is an intrinsic feature of the RND family. The low-resolution electronic maps obtained for the protein CmpL1 may serve as the foundation of future studies. In Chapter 3 we explore the therapeutic potential of the targeting of the transmembrane transporter MmpL3 in different Mycobacterium strains. Our collaborators studied the therapeutic effect of the most promising inhibitors of the MmpL3 Mtb transporter on certain multi-resistant mycobacterial non-tuberculous (NTB) strains. Based on our comparative structural modeling obtained by I-TASSER (6-8), we supplemented the biochemical data by highlighting the structural similarities and differences between the TB and NTB strains as well as their functional impacts. This chapter highlights the interest of direct or indirect targeting of MmpL3 in NTB species. Indeed, the efficacy of certain selected MmpL3 Mtb inhibitors on the treatment of NTB pulmonary infection have potential as generalizable treatment options for other NTB multi-resistant strains, or even to help address the problem of resistance to antibiotics and simplify current combination approaches. Other collaborative studies undertaking the same structural approaches were carried out for TriAxBC tripartite carriers (P. aeruginosa), efflux pumps belonging to the RND family. The purpose of Chapter 4 was to generate a structure of the complex and decipher its mode of assembly and expulsion of antibiotics from the intracellular environment. A quaternary structure model of TriAxBC was predicted by I-TASSER (6-8) and validated against its 4.3 Å electronic map generated by Cryo-EM. The TriAxBC complex was also characterized by gel filtration confirming an approximate size of 620 KDa and its trimer composition by SDS-PAGE. In conclusion, this study is combining different biochemical, genetic and structural approaches to highlight the need for a multidisciplinary approach to characterizing the structure function of RND transporters. The latter remain enigmatic; however, our contribution and the progress of others will allow the generation of new specific drugs targeting multiresistant strains.

Intake and Exhaust system noise makes a huge contribution to the interior and exterior noise of automobiles. There are a number of linear acoustic tools developed by institutions and industries to predict the acoustic properties of intake and exhaust systems. The present project discusses and validates, through measurements, the proper modelling of these systems using BOOST-SID and discusses the ideas to properly convert a geometrical model of an exhaust muffler to an acoustic model. The various elements and their properties are also discussed. When it comes to Acoustic properties there are several parameters that describe the performance of a muffler, the Transmission Loss (TL) can be useful to check the validity of a mathematical model but when we want to predict the actual acoustic behavior of a component after it is installed in a system and subjected to operating conditions then we have to determine other properties like Attenuation, Insertion loss etc,. Zero flow and Mean flow (M=0.12) measurements of these properties were carried out for mufflers ranging from simple expansion chambers to complex geometry using two approaches 1) Two Load technique 2) Two Source location technique. For both these cases, the measured transmission losses were compared to those obtained from BOOST-SID models. The measured acoustic properties compared well with the simulated model for almost all the cases.