To see the other types of publications on this topic, follow the link: Drawing instruments and materials.
Dissertations / Theses on the topic 'Drawing instruments and materials'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Drawing instruments and materials.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
MOREIRA, JOHANN SENRA. "CONSTRUCTION OF THE CONICS USING THE GEOMETRIC DRAWING AND CONCRETE INSTRUMENTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33061@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE MESTRADO PROFISSIONAL EM MATEMÁTICA EM REDE NACIONAL
O presente trabalho tem como objetivo facilitar o estudo das cônicas e ainda despertar o interesse do aluno para o desenho geométrico. Será apresentado que as curvas cônicas estão em nosso dia a dia, não só como beleza estética, mas também provocando fenômenos físicos amplamente utilizado pela arquitetura e engenharia civil, como acústica e reflexão da luz. Utilizaremos instrumentos para desenhar curvas que despertem a curiosidade dos alunos e faremos uso das equações e lugares geométricos a fim de demostrar tais recursos. Pretende-se assim que ao adquirir tais conhecimentos o aluno aprimore seu entendimento matemático e amplie seu horizonte cultural.
The present research aims to facilitate the study of the conics and also to arouse the interest of the student for the geometric drawing. The conic curves will be presented not only as they are in our day to day as aesthetic beauty but also as responsible for the physical phenomena widely used by architecture and civil engineering as well as acoustics and reflection of light. We will use instruments to draw curves that arouse the curiosity of the students, making use of the equations and locus in order to demonstrate such resources. It is intended that the student acquire this knowledge, improving his mathematical understanding and broadening his cultural horizon.
2
Hou, Chong Ph D. Massachusetts Institute of Technology. "Fiber drawing : beyond the scaling paradigm." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104183.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 93-97).
The emergence of multimaterial fibers that combine a multiplicity of solid materials with disparate electrical, optical, and mechanical properties into a single fiber presents new opportunities for extending fiber applications. Different functional fiber devices have been fabricated with a thermal co-draw approach. In order to make the thermal co-draw feasible, only materials with similar viscosity at the draw temperature are used, which excludes a wide range of metal and semiconductors that have good electrical property but not compatible viscosity profile. From the fiber structure point of view, the nature of the fiber drawing process makes fabricating a large quantity of fiber with identical inner structures feasible. The scalability of thermal drawing approach offers access to large quantities of devices however constrains the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibers will increase the utility of fiber devices. Also, the surface of the fiber is rarely studied though complex inner structure have been fabricated for different functionalities. Functionalize the fiber surface would give fiber the ability to better interact with the outer environment. This thesis seeks to address the abovementioned considerations, i.e. to expand materials selection for the fiber co-draw process and to explore variance of the fiber structure including breaking the inner structure translational symmetry and functionalize the outer surface. On the material side, a chemical reaction phenomenon is observed and studied in two different fiber drawing situations. In both cases, new composition is formed during the draw and play an important role in the formed fiber devices. On the structure side, relying on the principle of Plateau-Rayleigh instability, the fiber inner structure is designed to form a series of discrete semiconductor spheres contacting two metal buses after a thermal selective breakup process. This gives rise to photodecting devices in a silica-cladding fiber which shows a large working bandwidth. The fiber surface is also studied and successfully patterned with micron-scale features during the draw process. The formed patterned fiber surface shows potential in structural coloration and directional wetting.
by Chong Hou.
Ph. D.
3
Canales, Andrés. "Development of neural probes using thermal drawing." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111316.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 127-147).
The treatment of neurodegenerative and neurological conditions relies on better understanding the system that they afflict. However, the tools currently available to probe neural circuits are often limited to use in short-term studies primarily due to poor of biocompatibility. To address this challenge, flexible, minimally invasive neural probes were fabricated using a thermal drawing process, with polymers serving as their main structural constituent. Through the use of different polymers, probes containing arrays of tin electrodes as small as 5 [mu]m were fabricated, as were probes combining capabilities for electrical recording, optical stimulation, and drug delivery. A technique was developed to combine functionalities of these devices into a single probe to study the effect of optical stimulation with different waveforms on the brain activity. To break the longitudinal symmetry inherent to probes fabricated using the thermal drawing process, and to allow the incorporation of functionalities along the probe length, a method to combine thermal drawing with a method commonly used to fabricate neural probes, photolithography, was developed, along with the selection of the polymer that would allow consecutive processing using these two techniques. All of the fabricated probes were characterized and tested in vivo by implantation into mice and assessing their functionality. High signal-to-noise ratio (13±6) recordings were obtained using multielectrode arrays. Recordings of neural activity during simultaneous optical stimulation and drug delivery were performed with multifunctional probes. Hybrid probes combining metal electrodes with a polymer waveguide were used to study the response of large groups of neurons to different forms of optical stimuli. Most importantly, the biocompatibility of these probes was assessed over a 3 month period and compared favorably to that of steel microwires of similar size.
by Andrés Canales.
Ph. D.
4
Dorah, Michael Lee. "Process improvement methodologies applied to tube drawing." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12850.
Full textAbstract:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1992 and Thesis (M.S.)--Sloan School of Management, 1992.Includes bibliographical references (leaves 101-102)
by Michael Lee Dorah.
M.S.
5
Pernegger, Heinz, Norbert Wermes, Luigi Mele, Mar Capeans, Ettore Zaffaroni, Barbara Mehner, and Ingrid Jonak-Auer. "Innovating Advanced Radiation Instruments." Publishers Communication Group (PCG), 2018. http://epub.wu.ac.at/6507/1/s19.pdf.
Full textAbstract:
STREAM is a 4-year multi-site training network that aims at career development of Early Stage Researchers (ESRs) on scientific design, construction manufacturing and of advanced radiation instrumentation. STREAM targets the development of innovative radiation-hard, smart CMOS sensor technologies for scientific and industrial applications. The platform technology developed within the project will be tested in the demanding conditions posed by the CERN LHC detectors' environment as well as European industry leaders in the field of CMOS imaging, electron microscopy and radiation sensors. This leveraging factor will allow to fine-tune the technology to meet the requirements of industrial application cases on demand such as electron microscopy and medical X-ray imaging, as well as pathway towards novel application fields such as satellite environments, industrial X-ray systems and near-infrared imaging. The project will train a new generation of creative, entrepreneurial and innovative early-stage researchers and widen their academic career and employment opportunities. The STREAM consortium is composed of 10 research organisations and 5 industrial partners; the network will provide training to 17 ESRs. STREAM structures the research and training in four scientific work-packages which span the whole value-chain from research to application: CMOS Technologies Assessment, Smart Sensor Design and Layout, Validation and Qualification, Technology Integration, and Valorization.
6
Barker, Christopher Stuart. "An investigation into microbial contamination of orthodontic instruments and materials." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555658.
Full textAbstract:
There is little information on the microbial contamination of orthodontic materials received from the manufacturer and if orthodontists pre-sterilise new products prior to use. These items may also become contaminated on the clinic or during laboratory construction. Recent regulations for decontamination in primary dental care (HTM 01- 05) have been introduced requiring a 60 day limit for storage time of sterilised instruments. The aims of this investigation were to determine whether components of fixed and removable orthodontic appliances are free from microbial contamination prior to clinical use; to establish the current practice in orthodontics with regard to pre- sterilisation of new products and to investigate possible re-contamination of sterilised dental instruments. A range of orthodontic materials "as received" from the manufacturer and "bench-top exposed" items were investigated. Bacterial contamination during the construction of removable appliances was evaluated from initial impression, through to delivery of the final appliance. Molecular microbiological techniques were used to obtain bacterial DGGE profiles and facilitate 16S rDNA identification. Questionnaires were distributed to consultant orthodontists to determine their current pre-sterilisation regimes for new orthodontic products. Twenty five dental mirrors were sterilised. These were tested (5 mirrors at each time point) for microbial contamination immediately after autoclaving and then at 31,60,90 and 124 days. Bacteria were isolated from "as received" bands, archwires and impression trays, but the level of contamination was low (0-3.65x102 cfu ml"). This was similar for clinic items. Much higher levels were found on removable appliances (0.97x102-1.52xl03 cfu mll ). There was no cross-contamination from patients to the laboratory; contamination occurred within the laboratory itself. The majority of consultant-led departments do not pre-sterilise materials from the manufacturer (88-97%). There was no bacterial growth from sterilised dental mirrors after 5 days of incubation at 37°C at any time period from 0 to 124 days post sterilisation. In conclusion, materials and appliances are not free from bacterial contamination prior to use in patients; improved cross infection control procedures are needed within the orthodontic laboratory. There is no current evidence for the 60-day storage of sterilised dental instruments as advised by the Department of Health.
7
Horta, Cristina Maria Ribeiro da Silva Ramos e. "Percursos da azulejaria de interior no concelho das Caldas da Rainha." Master's thesis, Instituições portuguesas -- UNL-Universidade Nova de Lisboa -- FCSH-Faculdade de Ciências Sociais e Humanas -- -Departamento de Antropologia, 1999. http://dited.bn.pt:80/29495.
Full text
8
Ditcher, Kamille. "Exploring the Materials of Architectural Development." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32884.
Full textAbstract:
A factory inspired exploration in the architectural potential of space, material, sound, and light. This thesis is divided into chapters of the media types used for design. Primarily, the materials include photography, drawing, and modeling. The process yields overlap and interchange in ways of design that alter the ways of seeing and of advancing the work. Consequently, divisions of the book reoccur throughout the course of the thesis.Master of Architecture
9
Topic, Miroslav. "The effect of drawing strain on the fatigue behaviour of stainless and carbon steel wires." Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8749.
Full textAbstract:
Includes bibliographical references.A study has been made of the fatigue crack initiation and fatigue crack growth behaviour of three different steels in wire form, namely, an austenitic AISI 304 stainless steel, a corrosion resistant ferritic steel, 3CR12, and pearlitic high carbon steel. The stainless steel wires were produced in the laboratory at a drawing speed of 50 mm min-1, without intermediate annealing, whilst the high carbon pearlitic steel was manufactured commercially. Studies were made on stainless steel wires as a function of drawing strain between 0.09 and 0.585. Fatigue testing was carried out on an ESH servo hydraulic testing machine on both notched and unnotched samples and the S-N curves were used to evaluate the fatigue properties of the steels. Tests were performed with sinusoidal loading and load ratios of R= 0.048 and R=0.22 at a frequency of 2Hz. The microstructural evolution during drawing was characterised by optical and transmission optical microscopy, and x-ray diffraction. Fatigue crack growth and fracture surfaces were studied using scanning electron microscopy. In general, the fatigue limit was enhanced by increased drawing strain, but such strain also increased the subsequent crack propagation rates. The highest value of fatigue limit of 630 MPa was exhibited by the commercial pearlitic steel despite of its high notch sensitivity. Both shot peening of the steel wire surface and reducing the surface roughness by manual polishing increased the fatigue limit between 40 and 25 % respectively. The fatigue limit of AISI 304 stainless steel wire was improved from 215 MPa to 650 MPa after drawing to 0.585 strain. This improvement is attributed to the deformation-induced phase transformation of (ϒ) austenite to α'-martensite. X-ray diffractometer traces show that the amount of strain-induced martensite varied from 8% in the wires drawn at low strain (0.09) to 36% in the wire samples drawn to 0.585 strain. This study has established that approximately 20% of deformation-induced martensite, through drawing strain, is a critical amount which determines the subsequent fatigue response of this steel. If the amount of previously developed martensite is less than the critical amount of 20%, the martensite formed during the fatigue process will act beneficially by retarding fatigue cracking, raising the fatigue limit and resulting in a ductile fatigue fracture surface. However, in the presence of more than 20% of martensite, any martensite induced by cyclic strain will encourage more rapid crack initiation compared to a material containing less than 20% martensite which leads to more brittle fracture surface characteristics. The fatigue limit of 3CR12 steel wire was also improved from 130 MPa to 310 MPa (maximum stress) after drawing to 0.68 strain. The experimental results indicate that the use of drawn 3CR12 ferritic steel for wire application under cyclic conditions is restricted to low stress levels. However, the application of heat treatment and the resultant development of a dual-phase microstructure, improved the fatigue limit to 470 MPa. Based on the findings in this study, recommendations regarding material selection and drawing process optimisation for wire production to improve the fatigue performance of AISI 304 stainless steel is given.
10
Van, Scoyoc Marilyn Linda. "The development and evaluation of electronic wind controller instructional materials and techniques for the instrumental music educator /." Access Digital Full Text version, 1991. http://pocketknowledge.tc.columbia.edu/home.php/bybib/11168183.
Full textAbstract:
Thesis (Ed.D.)--Teachers College, Columbia University, 1991.Typescript; issued also on microfilm. Sponsor: Harold F. Abeles. Dissertation Committee: Robert Pace. Includes bibliographical references (leaves 115-119).
11
Adiguzel, Sinem. "Determining Surface Residual Stress In Steel Sheets After Deep Drawing And Bulging Processes." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613054/index.pdf.
Full textAbstract:
The aim of this thesis is to investigate the effects of bulging and deep drawing processes on St4 cold rolled steel by simulation and experimental characterization. In the simulations, commercial software programs MSC Marc and Simufact.forming were used. The experimental studies cover metallographic investigations, hardness measurements, and residual stress measurements. Residual stress measurements were carried out by different non- destructive characterization methodsX-ray diffraction and Magnetic Barkhausen Noise. The experimental and simulation results were correlated with each other.
12
Hua, Yueming. "Materials and methods for nanolithography using scanning thermal cantilever probes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22536.
Full textAbstract:
Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2008.Committee Chair: Henderson, Clifford; Committee Member: Hess, Dennis; Committee Member: King, William; Committee Member: Lu, Hang; Committee Member: Tolbert, Laren.
13
Wei, Zhiyong. "Thermo-fluid modeling and robust control of modern optic fiber drawing processes." Diss., Available online, Georgia Institute of Technology, 2004, 2004. http://etd.gatech.edu/theses/available/etd-04092004-135913/unrestricted/wei%5Fzhiyong%5F200405%5Fphd.pdf.
Full textAbstract:
Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2004.Kok-Meng Lee, Committee Chair ; Andrei G. Fedorov, Committee Member ; William E. Singhose, Committee Member ; David G. Taylor, Committee Member ; Zhi Zhou, Committee Member. Includes bibliographical references.
14
Wong, Wai-yum Veronica. "The effects of age, instruction, and materials on the ability to represent human figures by preschool children in Hong Kong." Click to view the E-thesis via HKUTO, 1990. http://sunzi.lib.hku.hk/HKUTO/record/B38627139.
Full text
15
Adnan, Johari Bin. "Development of instruments for the study of magnetic properties of recording materials, minerals and rocks." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316241.
Full text
16
WAN, DER-SHEN. "OPTICS FOR LARGE TELESCOPE." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184226.
Full textAbstract:
There are two topics in this dissertation: one is to develop new phase reduction algorithms for test interferograms especially of large optics and the other one is to find more accurate analytical expression of surface deflection due to gravity when the mirror is supported in the axial direction. Two new algorithms for generating phase maps from interferograms are developed. Both methods are sensitive to small-scale as well as large-scale surface errors. The first method is designed to generate phase from an interferogram that is sampled and digitized only along fringe centers, as in the case of manual digitization. A new interpolation algorithm uses the digitized data more efficiently than the fitting of Zernike polynomials, so the new method can detect small-scale surface error better than Zernike polynomial fitting. The second algorithm developed here is an automatic phase reduction process which works on test interferograms recorded by CCD camera and transferred digitally to a personal computer through a frame grabber. The interferogram results from interference of the test wavefront with a tilted reference wave-front. Phase is generated by assuming it to be proportional to the intensity of the interferogram, apart from changes of sign and offset occurring every half fringe so as to make the phase increase monotoically. The error of the new algorithm is less than 1/20 waves in the wavefront, which can be reduced further by averaging several phase maps which are generated by interferograms with random phase shifts. The new algorithm is quick and involves no smoothing, so it can detect surface errors on large mirrors on a scale of several centimeters. A new model is developed to calculate analytically the surface deflection of a mirror supported axially on multiple points. It is based on thin plate theory, but considerations of thickness variation of a curved mirror, lightweight honeycomb structure and shear are included. These additions improve the accuracy of the calculated surface deflection, giving results close to those obtained from the accurate but computer intensive finite element model.
17
Karana, Elvin. "Guidelines For A Materials Selection Source For Industrial Design Activity: A Survey On The Expectations Of Turkish Designers." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605174/index.pdf.
Full textAbstract:
This thesis focuses on the material selection process in industrial design activity and
existing material selection sources particularly used by industrial designers.
Therefore, in this study, the knowledge about materials the designers need, and
materials selection sources and the methods they use are explored. The aim is, to
propose guidelines for a materials selection source basing on the designers&rsquoneeds and expectations from such a guide. The thesis consists of a critical review of the literature on existing materials sources and a field study conducted with 20 industrial designers practicing in Turkey.
18
Ozan, Ezgi. "Preferences And Evaluation Criteria Of Preschool Children Related To Different Types Of Play Materials." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12610028/index.pdf.
Full textAbstract:
In this study, semi-structured interviews adopted from repertory grid studies are conducted with ten 5-year-old preschool children, during which children are asked to
evaluate four types of construction play materials and four types of metallophones.In the study, the important design attributes of these two types of play materials preferred by preschool children are analyzed by gathering their own evaluation criteria. Based on the interview data, children&rsquos preferences, evaluation criteria and the reasons behind their preferences are tried to be identified. The results of the study show that, children evaluated construction play materials considering method of construction, form of the pieces, color, size, types of pieces, types of constructions, ease of construction and material. Children evaluated metallophones considering color, placement of the keys, sound, being in the openbeing closed, form, size, storage of the mallets, weight, size of the mallets, form of the keys, coding, number of mallets, number of keys, height and material. The study also includes the analysis of the relationships between children&rsquo
s evaluation criteria for each product group and comparison of the evaluation criteria related to construction play materials and metallophones.
19
Guilleaume, Christina, Alexander Brosius, and Ali Mousavi. "Investigation of Alternative Polymer Composite Materials for Forming Applications." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-235022.
Full textAbstract:
In diesem Paper werden Untersuchungen eines Tiefziehwerkzeugs aus Mineralguss vorgestellt. Der Grund für die Verwendung von Mineralguss als alternativen Werkstoff für schnelle Werkzeuge liegt in den relativ geringen Initialkosten zur Herstellung und seiner Eignung für Kleinserien und Prototypenversuche. Ähnliche Konzepte mit Werkzeugen aus Mineralguss haben gezeigt, dass eine entscheidende Grenze in der Tribologie und dem bei diesem Werkstoff großen Oberflächenverschleiß liegt. Daher fokussiert das vorliegende Paper auf die Ergebnisse der Analyse verschiedener Mineralgussmischungen unter Anwendung von Streifenzugbiegeversuchen. Die Reibzahl wurde hierbei berechnet und vergleichend einem Stahlwerkzeug gegenübergestelltThis paper presents the investigation of polymer concrete drawing tools for deep drawing operations. The goal of using polymer concrete as an alternative material is a rapid tooling process at relatively low initial tools costs that is suitable for small batch production. Similar concepts based on hydraulic concrete and polymer composites have shown that the surface tri-bology and consequently wear is the main limiting factor. Therefore, this paper focusses on the results of strip draw-bending tests with different polymer concrete mixtures. The friction coefficient is calculated and compared to a steel tool
20
Pathak, Shantanu Chaturvedi. "Characterization of plasma-polymerized polyethylene glycol-like films." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/31789.
Full textAbstract:
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Dr. Dennis W. Hess; Committee Member: Dr. Clifford L. Henderson; Committee Member: Dr. J. Carson Meredith; Committee Member: Dr. L. Andrew Lyon; Committee Member: Dr. Mark R. Prausnitz. Part of the SMARTech Electronic Thesis and Dissertation Collection.
21
Souza, Campelo Clayton. "Design, development, and validation of chitosan-based coatings via catechol chemistry for modulating healthcare materials." Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/67732.
Full textAbstract:
Depuis la préhistoire, plusieurs matériaux ont été utilisés pour fabriquer des instruments et des appareils de santé. Au cours des dernières décennies, avec l’apparition du terme « biomatériau », les matériaux ont été conçus pour contrôler des réactions biologiques spécifiques, pour augmenter la durée de vie des biodispositifs et la qualité de vie des patients dans le monde. Cependant, indépendamment de la nature du matériau, ou au sens strict du biomatériau, et de la fonction remplie, ils sont susceptibles aux phénomènes de surface causés par son environnement. Certains phénomènes intéressants incluent l’action des protéines, des électrolytes et des cellules sur les surfaces métalliques. Ces interactions peuvent entraîner le développement de complications telles que la formation de thrombus, la corrosion et la calcification, qui affecteront le fonctionnement des dispositifs, et la contamination bactérienne qui peut transformer la surface en vecteur de propagation de maladies. Des recherches ont exploité des stratégies de modification de surface pour minimiser ou éviter ces complications. Ces approches demandent du temps et des efforts pour développer une surface efficace pour chaque cas. Sur cette base, l’objectif principal de ce travail était de concevoir et de développer des revêtements à base de chitosane à utiliser dans le revêtement de surfaces métalliques et de dispositifs utilisés dans le système de santé et de modifier ces surfaces pour moduler la réponse biologique. Pour atteindre cet objectif, le projet de recherche a été divisé en trois parties. La première était le greffage du chitosane utilisant de la dopamine comme ancre. La deuxième était le développement d’un greffage original en une étape remplaçant la dopamine par l’acide caféique. La dernière était la modification du revêtement de chitosane pour moduler la réponse biologique de la surface. À chaque étape, les surfaces revêtues ont été caractérisées par analyses biologiques et physico-chimiques. Les résultats ont démontré que la méthodologie développée produisait des revêtements de chitosane qui possédait des réponses biologiques et des performances physico-chimiques favorables et qui pouvait être modifiés pour améliorer ou conférer la propriété souhaitée. De plus, cette méthodologie permet de produire une plateforme capable d’être appliquée sur une large gamme de complications en raison de sa modulabilité. Cela représente une diminution de la consommation de temps pour créer une nouvelle surface à partir du zéro pour chaque situation.Since prehistoric times, several materials have been used to make health instruments and devices. In recent decades, with the appearance of the term "biomaterial", materials have been designed to control specific biological reactions, to increase the lifespan of biodevices and the quality of life of patients around the world. However, regardless of the nature of the material, or in the strict sense of the biomaterial, and the function fulfilled, they are susceptible to the surface phenomena caused by its environment. These phenomena include the action of proteins, electrolytes, and cells on metal surfaces. These interactions can lead to the development of complications such as thrombus formation,corrosion, and calcification, which will affect the functioning of the devices, and bacterial contamination, which can transform the surface into a vector for the spread of disease. Researches were made on the use of surface modification strategies to minimize or avoid these complications. These approaches require time and effort to develop an effective surface for each case. On this basis, the main objective of this work was to design and develop chitosan-based coatings to coat metallic surfaces and devices used in the health care system and to modify these surfaces to modulate the biological response. To accomplish this objective, the research project was divided into three parts. The first was the grafting of chitosan using dopamine as an anchor. The second was the development of an original one step graft replacing dopamine with caffeic acid. The last was the modification of the chitosan coating to modulate the biological response of the surface. At each stage, the coated surfaces were characterized by biological and physicochemical analyzes. The results obtained showed that the developed methodology produced chitosan coatings that had favorable biological responses and physicochemical performances, and that it could be modified to improve or confer the desired property. Besides, this methodology makes it possible to produce a platform able to be applied to many complications due to its modularity. It represents a reduction in the consumption of time to create a new surface from scratch for each situation.
22
Peng, Xuan. "Co-deformation and bonding of multi-component billets with application to Nb-Sn based superconductor processing." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127096847.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xix, 182 p.; also includes graphics (some col.). Includes bibliographical references (p. 177-182). Available online via OhioLINK's ETD Center
23
Pinto, Neuza Filipa Silva Simões. "A Figura Complexa de Rey na criança com alergia." Master's thesis, Instituto Superior de Psicologia Aplicada, 2005. http://hdl.handle.net/10400.12/808.
Full textAbstract:
Dissertação de Mestrado em PsicossomáticaTendo por base os inúmeros estudos realizados sobre a figura complexa de Rey (forma A), esta investigação pretende explorar alguns aspectos relacionados com a problemática subjacente às crianças com diagnóstico médico de alergia, à luz e uma perspectiva psicossomática. A amostra em estudo foi recolhida na consulta de Imunoalergologia da Clínica Pediátrica Universitária do Hospital de Santa Maria, em Lisboa, mediante a análise do processo clínico de cada criança. É composta por 22 crianças, com idades compreendidas entre os seis e os nove anos de idade inclusivé, com diagnóstico médico de alergia confirmado pelos exames complementares de diagnóstico: Testes cutâneos em prick positivos e e/ou exames in vitro _ IgE total sérica e IgE específica. Este estudo trata-se de uma investigação clínica-psicossomática de carácter não experimentai já que não se pretende introduzir modificações ao longo da recolha dos dados e descritivo visando desenvolver ideias ou hipóteses sobre o modo como os factos se encontram relacionados entre si. É exploratório e transversal na medida era que possibilita a recolha de dados sobre a eventual plausibilidade do problema apenas num determinado momento. Na selecção dos instrumentos considerou-se que, para além da figura complexa de Rey (forma A) deveriam ser utilizados outros recursos que servissem de suporte a uma melhor compreensão dos dados obtidos, nomeadamente, questionário-anamnese, desenho da figura humana, desenho de círculos representativos da família e Rorschach. No que diz respeito ao funcionamento da criança com alergia foi possível verificar que, estas apresentam algumas particularidades ao nível do seu plano genético e imunitário, ritmos biológicos e corporais e vida relacional/psicológica, no entanto, não é possível a constatação de uma frequência significativa de traços estruturais relativamente a estes aspectos referidos na literatura por inúmeros autores. Pode falar-se, então, de especificidades associadas a uma determinada patologia psicossomática que é a alergia. Conclui-se esta investigação afirmando que a figura complexa de Rey encerra em si mesma a possibilidade de uma análise precisa dos diferentes aspectos que abordam o funcionamento da criança com alergia de uma perspectiva psicossomática, nomeadamente, ao nível da organização do espaço e do tempo, da projecção da imagem do corpo, da lateralidade e ritmicidade entre percepção e projecção e os recursos do imaginário. A figura complexa de Rey revela uma versatilidade e riqueza em termos de princípios e objectivos que, em última análise e em termos teórico-práticos, nos leva a considerá-la como uma exímia prova de avaliação em clínica psicossomática. Esta adequação, no entanto, não deve ser reduzida a este campo de análise visto poder, pelo seu valor, abranger outras áreas de estudo.
24
Leydier, Marlène. "Méthodes complémentaires pour l'étude de verres et liquides fondus sur grands instruments : structure et dynamique." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00623032.
Full textAbstract:
Ce travail se place dans le cadre de l'utilisation des grands instruments (sources de neutrons et synchrotrons) pour l'étude de la structure et de la dynamique de matériaux désordonnés (liquides et verres). En particulier, trois études sont présentées. La première, est une étude structurale de verres Ln2O3-Al2O3-SiO2 où Ln représente les cations Sc, Y et La. Nous avons combiné des résultats obtenus par diffraction des rayons X et des neutrons et par absorption des rayons X. L'étude est focalisée sur la détermination des distances interatomiques et des coordinences pour les trois paires Si-O, Al-O et Ln-O. La seconde est une étude structurale de l'oxyde de fer FeO à l'état fondu. Des expériences de photoémission de rayons X au seuil d'absorption du fer ont été associées à des mesures de diffraction de rayons X et de neutrons. Les résultats obtenus ont permis de définir un modèle structural cohérent pour le FeO liquide. La troisième est une étude de la dynamique dans le composé CaAl2O4 fondu. La diffusion inélastique des rayons X a permis de déterminer les vitesses du son apparente et isotherme ainsi que la viscosité longitudinale. Ces mesures ont été complétées par des expériences de diffusion quasiélastique de neutrons à partir desquelles il a été possible de déterminer des coefficients de diffusion atomique. Ce travail montre l'intérêt de combiner différentes techniques expérimentales pour l'étude des verres et des milieux fondus. Il montre également la nécessité d'associer aussi des techniques de modélisation comme la dynamique moléculaire.
25
Wong, Wai-yum Veronica, and 黃蕙吟. "The effects of age, instruction, and materials on the ability to represent human figures by preschool children in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B38627139.
Full text
26
Otto, Ernst. "Development of superconducting bolometer device technology for millimeter-wave cosmology instruments." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:30a1103a-ea7a-4b08-ba92-665cbd9740e0.
Full textAbstract:
The Cold-Electron Bolometer (CEB) is a sensitive detector of millimeter-wave radiation, in which tunnel junctions are used as temperature sensors of a nanoscale normal metal strip absorber. The absorber is fed by an antenna via two Superconductor-Insulator-Normal metal (SIN) tunnel junctions, fabricated at both ends of the absorber. Incoming photons excite electrons, heating the whole electron system. The incoming RF power is determined by measuring the tunneling current through the SIN junctions. Since electrons at highest energy levels escape the absorber through the tunnel junctions, it causes cooling of the absorber. This electron cooling provides electro-thermal feedback that makes the saturation power of a CEB well above that of other types of millimeter-wave receivers. The key features of CEB detectors are high sensitivity, large dynamic range, fast response, easy integration in arrays on planar substrates, and simple readout. The high dynamic range allows the detector to operate under relatively high background levels. In this thesis, we present the development and successful operation of CEB, focusing on the fabrication technology and different implementations of the CEB for efficient detection of electromagnetic signals. We present the CEB detector integrated across a unilateral finline deposited on a planar substrate. We have measured the finline-integrated CEB performance at 280-315 mK using a calibrated black-body source mounted inside the cryostat. The results have demonstrated strong response to the incoming RF power and reasonable sensitivity. We also present CEB devices fabricated with advanced technologies and integrated in log-periodic, double-dipole and cross-slot antennas. The measured CEB performance satisfied the requirements of the balloon-borne experiment BOOMERANG and could be considered for future balloon-borne and ground-based instruments. In this thesis we also investigated a planar phase switch integrated in a back-to-back finline for modulating the polarization of weak electromagnetic signals. We examine the switching characteristics and demonstrate that the switching speed of the device is well above the speed required for phase modulation in astronomical instruments. We also investigated the combination of a detector and a superconducting phase switch for modulating the polarization of electromagnetic radiation.
27
Liu, Jie. "Characterization of New Rotary Endodontic Instruments Fabricated from Special Thermomechanically Processed NiTi Wire." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244643081.
Full text
28
Bakas, Konstantinos. "Construction and testing of compact low noise hydrophones with extended frequency response." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FBakas.pdf.
Full text
29
Galve, Salgado Miguel. "Impact of medical equipment tracking in a health care system." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4639.
Full textAbstract:
Thesis (M.S.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 23, 2007) Includes bibliographical references.
30
Konh, Bardia. "Smart Surgical Needle Actuated by Shape Memory Alloys for Percutaneous Procedures." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/375030.
Full textAbstract:
Mechanical EngineeringPh.D.
Background: Majority of cancer interventions today are performed percutaneously using needle-based procedures, i.e. through the skin and soft tissue. Needle insertion is known as one of the recent needle-based techniques that is used in several diagnostic and therapeutic medical procedures such as brachytherapy, thermal ablations and breast biopsy. The difficulty in most of these procedures is to attain a precise navigation through tissue reaching target locations. Insufficient accuracy using conventional surgical needles motivated researchers to provide actuation forces to the needle’s body for compensating the possible errors of surgeons/physicians. Therefore, active needles were proposed recently where actuation forces provided by shape memory alloys (SMAs) are utilized to assist the maneuverability and accuracy of surgical needles. This work also aims to introduce a novel needle insertion simulation to predict the deflection of a bevel tip needle inside the tissue. Development of a model to predict the behavior of the needle steering in the soft tissue has been always a point of interest as it could improve the performance of many percutaneous needle-based procedures. Methods: In this work first, the actuation capability of a single SMA wire was studied. The complex response of SMAs was investigated via a MATLAB implementation of the Brinson model and verified via experimental tests. The material characteristics of SMAs were simulated by defining multilinear elastic isothermal stress-strain curves. Rigorous experiments with SMA wires were performed to determine the material properties as well as to show the capability of the code to predict a stabilized SMA transformation behavior with sufficient accuracy. The isothermal stress-strain curves of SMAs were simulated and defined as a material model for the Finite Element Analysis of the active needle. In the second part of this work, a three-dimensional finite element (FE) model of the active steerable needle was developed to demonstrate the feasibility of using SMA wires as actuators to bend the surgical needle. In the FE model, birth and death method of defining boundary conditions, available in ANSYS, was used to achieve the pre-strain condition on SMA wire prior to actuation. This numerical model was validated with needle deflection experiments with developed prototypes of the active needle. The third part of this work describes the design optimization of the active using genetic algorithm aiming for its maximum flexibility. Design parameters influencing the steerability include the needle’s diameter, wire diameter, pre-strain, and its offset from the needle. A simplified model was developed to decrease the computation time in iterative analyses of the optimization algorithm. In the fourth part of this work a design of an active needling system was proposed where actuation forces of SMAs as well as shape memory polymers (SMPs) were incorporated. SMP elements provide two major additional advantages to the design: (i) recovery of the SMP’s plastic deformation by heating the element above its glass transition temperature, and (ii) achieving a higher needle deflection by having a softer stage of SMP at higher temperatures with less amount of actuation force. Finally, in the fifth and last part of this study, an Arbitrary-Lagrangian-Eulerian formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. A 150mm long needle was considered to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Some additional assumptions were made to maintain a reasonable computational time, with no need of parallel processing, while having practical accuracies. Three experimental tests of needle steering in a soft phantom were performed to validate the simulation. Results: The finite element model of the active needle was first validated experimentally with developed prototypes. Several design parameters affecting the needle’s deflection such as the needle’s Young’s modulus, the SMA’s pre-strain and its offset from the neutral axis of the cannula were studied using the FE model. Then by the integration of the SMA characteristics with the automated optimization schemes an improved design of the active needle was obtained. Real-time experiments with different prototypes showed that the quickest response and the maximum deflection were achieved by the needle with two sections of actuation compared to a single section of actuation. Also the feasibility of providing actuation forces using both SMAs and SMPs for the surgical needle was demonstrated in this study. The needle insertion simulation was validated while observing less than 10% deviation between the estimated amount of needle deflection by the simulation and by the experiments. Using this model the effect of needle diameter and its bevel tip angle on the final shape of the needle was investigated. Conclusion: The numerical and experimental studies of this work showed that a highly maneuverable active needle can be made using the actuation of multiple SMA wires in series. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies.
Temple University--Theses
31
Sonmez, Caglar. "Investigation Of The Deep Drawability Of Steel And Aluminum Sheets By Finite Element Simulation." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606007/index.pdf.
Full textAbstract:
Sheet metal forming processes, especially deep drawing processes give diverse results by various materials. Extreme differences occur between steel sheets and aluminum sheets. The main causes of this variance are anisotropy, elastic modulus and microscopic material properties.
The aim of this thesis is to evaluate the deep drawing properties and also to develop suitable process parameters for aluminum and steel sheets by finite element simulation. In the simulation, the commercial dynamic-explicit code PAM-STAMP has been used. The reliability of the finite element package was verified by a comparison with the NUMISHEET 2002 benchmarks. Additionally, a commercial part is numerically simulated for experimental verification. The results of the simulations have been compared with several experiments that were performed in Metallurgical and Materials Engineering and Mechanical Engineering Departments. Finally, the simulation results are compared with analytical expressions for verification of results.
The materials investigated for the deep drawability comparison is a deep drawing quality mild steel and an aluminum alloy designated as 6111-T4. For experimental verification St4 steel is used.
Results are in agreement with the fact that aluminum and steel materials behave differently upon deep drawing in terms of the onset of failure, wrinkling and final shape. Aluminum is found to be less formable than steel for cup drawing operations.
32
Hany, Sara. "Études structurales de l'acier cryogénique 9 % Ni utilisant les méthodes avancées sur les grands instruments." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0382/document.
Full textAbstract:
Face à l'augmentation générale de la consommation d'énergie, l'exploitation du Gaz Naturel Liquéfié (GNL) connaît un intérêt croissant, d'où un marché en forte expansion avec de nombreux projets d'installation de terminaux méthaniers. Les installations de gaz naturel liquéfié ont la particularité de fonctionner à très basses températures (~ -160°C), ce qui exige l'utilisation de matériaux particuliers présentant des caractéristiques adaptées aux températures extrêmes. Cette étude nous a permis d'évaluer le comportement structural de l'acier 9% Ni métal de base, consistant en une phase ferrique d'un grain martensitique en présence d'austénite, utilisé dans la construction du réservoir interne de stockage du GNL.Ce métal présente des domaines inhomogènes au niveau mésoscopique principalement formés par la phase austénitique riche en Ni mis en évidence par la diffusion des neutrons aux petits angles. Suite à une déformation mécanique, une augmentation du pourcentage de la phase austénitique est observée au niveau de la zone de déformation plastique. Ce phénomène est probablement dû à la diffusion préférentielle du Ni le long des dislocations au cours du traitement mécanique et son accumulation au niveau de cette zone. Au cours du processus de soudage, une diffusion intergranulaire du Ni au sein de la zone affectée thermiquement (ZAT) est observée. Ce phénomène permet de stabiliser la phase austénitique au niveau de la ZAT et d'améliorer les propriétés mécaniques au sein de cette zone. La déformation mécanique appliquée à basse température sur l'acier 9% Ni, ne détériore pas les propriétés structurales de ce matériauDue to the overall increase in energy consumption, the use of the Liquefied Natural Gas (LNG) is experiencing an increasing interest, resulting in a rapidly growing market with many LNG terminals installation projects. LNG installations have the particularity of operating at extremely low temperatures (~ -160°C), which requires materials with specific characteristics suitable to extreme temperatures. This study allowed us to evaluate the structural behavior of the base metal 9% Ni steel, consisting of a ferritic phase with a martensitic grain in the presence of residual austenite, used in the construction of the inner wall of LNG storage tank. This metal presents, at the mesoscopic level, non-homogeneous domains formed primarily by the Ni rich austenitic phase revealed by small angle neutron scattering. Due to a mechanical deformation, an increase in the percentage of the austenitic phase is observed at the plastic deformation zone. This phenomenon is probably due to the preferential diffusion of Ni along dislocations during the mechanical treatment and its accumulation at this area. During the welding process, a grain boundary diffusion of Ni in the Heat Affected Zone (HAZ) is observed. This phenomenon allows the stabilization of the austenitic phase at the HAZ and the improvement of the mechanical properties within this area. Mechanical deformation applied at low temperatures on the 9% Ni steel, does not deteriorate the structural properties of the material
33
Hung, Chuan-Hsi. "Synthesis and Characterization of Carbonized Poly (Divinylbenzene) Microspheres for Carbon/Nanodiamond/Polymer-Based Core-Shell Materials and Applications of This Mixed-Mode Phase to High-Performance Liquid Chromatography." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5497.
Full textAbstract:
This work focuses on improving the quality of carbon-based core-shell materials for high performance liquid chromatography (HPLC) via the characterization of the core materials, and also the development of chromatographic methods (separations) for them. In the early part of this work, I applied organic synthesis to make uniform, spherical poly(divinylbenzene) (PDVB) microspheres, and then carbonized them to prepare carbon core materials for core-shell particle synthesis. Here, I studied in detail the surface and material properties of these particles with multiple instruments, which allowed me to describe the physical and chemical changes that took place during each treatment. The uniform, spherical carbon core materials greatly improved the efficiency of the previously developed carbon-based core-shell HPLC columns from ca. 70,000 plates per meter (N/m) to ca. 110,000 N/m for various alkyl benzenes. Later, I focused on generating application notes to showcase these mixed-mode HPLC columns. Here, liquid chromatography mass spectrometry (LC-MS) was used for the detection of analytes that lack chromophores for UV detection. In this dissertation, Chapter 1 contains a historical background and theory of HPLC along with a review of the use of carbon-based core-shell materials for elevated pH and temperature applications. Chapter 2 describes the improvement of the efficiency of carbon-based materials for HPLC using carbonized PDVB microspheres as the carbon core material. Chapter 3 is a study on the characterization of carbonized PDVB microspheres with multiple instruments. Chapter 4 describes the separation of cannabinoids using three types of carbon-based mixed-mode HPLC columns. Chapter 5 consists of (i) guidelines for the retention mechanism of the core-shell particles that have been commercialized for chromatography by Diamond Analytics, a US Synthetic Company in Orem, Utah, and (ii) application notes for these columns. Finally, Chapter 6 discusses possible future work.
34
Kilic, Emine. "Effects Of The Design Of Toys On The Child-toy Interaction In Special Education." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608892/index.pdf.
Full textAbstract:
The play materials designed for special education are commonly used by children with various disabilities. This study overviews these materials from the perspectives of special needs, special user groups and special education. Furthermore, the effects of different disabilities on the interactions of the children with the same toys are investigated, within the light of those special cases. The base of the study is constructed with a literature review on toys, play and special education, followed by observations that are performed in a special education centre with six subjects having different disabilities, namely Rett&rsquos syndrome, mental retardation, hyperactivity, Down&rsquo
s syndrome, cerebral palsy and autism. The study is concluded with compared results of the observations and design implications derived from the interactions between the toys and children.
35
Almeida, Maria Margarida Cavaleiro Ferreira Pinto de. "Identidade de género em crianças instáveis com cinco anos de idade." Master's thesis, Instituto Superior de Psicologia Aplicada, 2002. http://hdl.handle.net/10400.12/416.
Full text
36
Yan, Zewu. "Detection of defects and thermal distortions in large-size gravitational-wave interferometer test masses." University of Western Australia. School of Physics, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0050.
Full textAbstract:
Advanced Laser Interferometric Gravitational Wave Detectors, based on current infrastructure (in particular, the Advanced LIGO detectors), are being planned to significantly increase the sensitivity to gravitational wave strain in the near future. To upgrade the existing detectors requests implementing very high optical power, as well as very high circulating power in the arm cavities; these measures will increase the sensitivity at the shot noise floor by one order of magnitude. However, such extremely high power circulation in the cavities will cause optical distortions in the test masses. Thermal distortions arise from the optical power absorption by defects or inhomogeneities in test masses, resulting in wavefront deformations, which have important consequences for the power buildup of the Radio-Frequency (RF) sidebands in the recycling cavities, thus degrading the performance of the detectors. The degree of this sensitivity degradation in the shot noise floor, due to optical distortions induced by defects or inhomogeneities (i.e. imperfections) in test masses in Advanced Laser Interferometric Gravitational-wave Detectors, is dependent on the test mass optical quality; while the sensitivity degradation in the thermal noise floor is dependent on the test mass mechanical properties. For this reason, it is compulsory to use high optical and mechanical quality test mass materials in the advanced interferometer detectors. Fused silica has been used for test masses in detectors, while sapphire has been planned to be used for test mass substrates in the proposed Large-scale Cryogenic Gravitational-wave Telescope (LCGT) project. Other materials, such as calcium fluoride (CaF2), are also attractive, especially for cryogenic detectors. However, for the state-of-theAbstract II art facilities, it is difficult to manufacture very uniform, defect-free, inhomogeneity-free, high-quality, and large-size samples. Thus, the qualities of sapphire and calcium fluoride single crystal samples were investigated and evaluated, to ensure that they have suitable properties for use in interferometer detectors, i.e. with an adequately low level of imperfections, but also with high mechanical quality factor (Q-factor). This thesis describes research done in the endeavour to investigate bulk defects or inhomogeneities in test masses, as well as their induced thermal distortions, which appear at a high optical power in Laser Interferometric Gravitational-wave Detectors. An Automatic Rayleigh Scattering Mapping System (ARSMS) to examine the optical property of large-size test masses is described. This ARSMS enables quantitative high-resolution 3D mapping of defects or inhomogeneities in optical materials. The measured 3D defect distribution mapping of optical materials can assist in the design of suitable configurations of test masses in high optical power interferometers. In addition, a very sensitive Hartmann wavefront sensor was used to actively monitor the thermal distortions due to bulk and coating absorption in test masses. A very strong thermal distortion in these test masses was observed in the Gingin facility, demonstrating that thermal distortions could be a critical issue in advanced interferometer detectors. A negative thermo-optical coefficient material, to be used in a thermal distortion compensation method, was investigated for the compensation of very localised distortions due to imperfections. This thesis also includes experimental and theoretical studies of the scattering, absorption, and birefringence mechanisms, thermal distortion effects, and optimal compensation methods for test masses.
37
Finkel, Kelsey Jo. "Exploring the writer's toolbox : a study of how writers and their use of writing implements and surfaces relate to their ways of thinking for writing." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:daaae0e7-10f0-4c9f-bbe3-8157c2fa47df.
Full textAbstract:
The state of writing abilities throughout the United States presents an urgent issue. Low student achievement in English Language Arts (ELA) exams and standardized English assessments persist (National Center for Education Statistics, 2012), while businesses spend billions of dollars on remedial writing instruction (Dillon, 2008). Technology is increasingly cited as a potential solution to these issues. Evidence for this is limited, as is existing research into the basis of the issues that technology might address. On account of that context, this thesis turns to a basic distinction between digital and non-digital writing: the writing surface and implement, or pen and paper - screen and keyboard. Conceptualizing such artefacts through a view of writing as a way of thinking raises the following question, which is this study's guiding inquiry. Might we use digital implements and surfaces to support the ways of thinking involved in composing written works of semantic cohesion? Building on research into writing as thinking, the study presented in this document analyses how uses of writing surfaces and implements relate to ways of thinking while writing, and which contextual factors influence those relationships. Drawing on a neuro-anthropological approach, the study focuses on the writer's mind as the driver and source of the lived experience of writing. Expert writers, therefore, are considered to be those who exhibit the ways of thinking while writing to which other writers aspire. To examine a range of uses of writing surfaces and implements with reference to expert writers' ways of thinking, the study was conducted in two parts. Part 1involved a content analysis of published interviews with professional writers. This generated a framework through which to conduct in-depth qualitative research with college student writers - part 2. This thesis is as much about thinking while writing as it is about the different tools available for writing. As such, the study refutes the hyperbolic and deterministic claims about technology and writing, and finds that technology is not leading to new ways of thinking while writing. Instead, surfaces and implements available allow writers to change how they practise their ways of thinking while writing. By considering this distinction and developing understandings of the dynamics involved and their implications, writers may begin to realize the potential of technology for writing. Ultimately, this thesis contributes to existing theories on writing through an informed discussion of how to think about implements and surfaces in ways that support writerly thinking, and by offering fresh ways to think about the lived practice of writing.
38
Rawnsley, Richard William. "From Gutenberg to gigabytes: Writing machines in historical perspective." CSUSB ScholarWorks, 1995. https://scholarworks.lib.csusb.edu/etd-project/1105.
Full text
39
Nilforoushan, Niloufar. "Out-of-equilibrium electron dynamics of Dirac semimetals and strongly correlated materials." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS573/document.
Full textAbstract:
Les matériaux quantiques ont récemment introduit en physique de la matière condensée pour unifier tous les matériaux dans lesquels les fortes corrélations électroniques gouvernent les propriétés physiques du système (e.g. les isolants de Mott) et les matériaux dont les propriétés électroniques sont déterminées par la géométrie de la fonction d’onde (e.g. matériaux de Dirac). Ces matériaux montrent des propriétés émergentes résultantes de l’intrication de différents degrés de libertés : la charge, le spin et le moment orbital, donnant lieu aux propriétés topologiques des électrons. L’étude de ces interactions et des compétitions entre les degrés de liberté pertinents nécessite l’utilisation de techniques pompe-sonde ultra-rapides. Particulièrement, les pulses laser femtosecondes interagissent uniquement avec les électrons pour les placer dans un état hors-équilibre décrit par des distributions de type non Fermi-Dirac. La dynamique subséquente implique de nombreux processus, avec un temps de relaxation relié aux constantes de couplage. De plus, dans les techniques résolues en temps, la lumière peut agir comme un paramètre externe, différent des paramètres thermodynamiques, pour explorer le diagramme de phase. Cela nous donne l’opportunité de stabiliser de nouveaux états inaccessibles par des chemins thermiques quasi-adiabatiques ou de manipuler les propriétés physiques des systèmes.Dans cette thèse, nous avons réalisé différentes expériences dans le but d’étudier les propriétés à l’équilibre et hors équilibre de deux matériaux corrélés: BaCo₁₋ₓNiₓS₂ et (V₁₋ₓMₓ)₂O₃.La première partie de ce projet a été dédiée principalement à l’étude de BaNiS₂, le précurseur métallique de la transition de Mott dans BaCo₁₋ₓNiₓS₂ . En utilisant l’ARPES, nous avons étudié la structure de bandes électroniques de BaNiS₂ dans toute la zone de Brillouin. L’expérience, combinée avec des calculs théoriques, révèle un nouveau type de cône de Dirac bidimensionel à caractère orbitalaire d et induit par les corrélations. Le croisement des bandes est protégé par les symétries particulières de la structure cristalline. Nous avons aussi mesuré la structure de bandes de l’isolant de Mott BaCoS₂ dans ses phases magnétique et non magnétiques.Dans la seconde partie, nous avons étudié la dynamique électronique hors équilibre de BaNiS₂ et (V₁₋ₓMx)₂O₃. Grâce à des mesures tr-ARPES et tr-Réflectivité, nous avons observé une renormalisation non thermique et ultra-rapide du cône de Dirac dans BaNiS₂. Ce phénomène est purement provoqué par les excitations électroniques et est stabilisé par l’intéraction entre les électrons et les phonons. De plus, en utilisant différentes techniques pompe-sonde (tr-XRD basé sur XFEL et tr-Réflectivité) nous avons aussi exploré des phases hors-équilibre du matériau prototype de Mott-Hubbard (V₁₋ₓMx)₂O₃ appartenant à différentes parties de son diagramme de phase. Nos résultats montrent une phase transitoire non thermique se développant immédiatement après la photoexcitation ultra-rapide et durant quelques picosecondes dans les phases métallique et isolantes. Cette phase transitoire est accompagné par une distorsion structural qui correspond à un durcissement du réseau et est marqué par un “blue shift” du mode phononique A₁g. Nos résultats soulignent l’importance du remplissage des orbitales aussi bien que des effets important des forts couplages électron-réseau sélectifs dans les matériaux fortement corrélésQuantum materials is a new term in condensed matter physics that unifies all materials in which strong electronic correlation governs physical properties of the system (e.g. Mott insulators) and materials whose electronic properties are determined by the geometry of the electronic wave function (e.g. Dirac materials). These materials show emergent properties– that is, properties that only appear by intricate interactions among many degrees of freedom, such as charge, spin and orbital, giving rise to topological properties of electrons. The study of these interactions and competitions between the relevant degrees of freedom demands applying ultrafast pump-probe techniques. Particularly, femtosecond laser pulses act only on the electrons and set them to an out-of-equilibrium state inexplicable by the Fermi-Dirac distribution. The ensuing dynamics involves various processes and the rate at which the relaxation occurs is related to the coupling constants. Moreover, in time-resolved pump-probe techniques light can act as an additional external parameter to change of the phase diagram – different from thermodynamic parameters. It gives us the opportunity of stabilizing new states inaccessible by quasi-adiabatic thermal pathways or eventually manipulating the physical properties of the systems.In this thesis, we performed different experiments in order to study the equilibrium and out-of-equilibrium properties of two correlated compounds: BaCo₁₋ₓNiₓS₂ and (V₁₋ₓMₓ)₂O₃.The first part of the project was mainly devoted to the study of BaNiS₂ that is the metallic precursor of the Mott transition in BaCo₁₋ₓNiₓS₂. By applying ARPES, we studied the electronic band structure of BaNiS₂ in its entire Brillouin zone. These results combined with some theoretical calculations give evidence of a novel correlation-induced and two-dimensional Dirac cone with d-orbital character. The band crossing is protected by the specific symmetries of the crystal structure. We also investigated the electronic band structure of the Mott insulator BaCoS₂ in its magnetic and nonmagnetic phases.In the second part, we studied the out-of-equilibrium electron dynamics of BaNiS₂ and (V₁₋ₓMx)₂O₃. By means of tr-ARPES and tr-reflectivity measurements, we observed an ultrafast and non-thermal renormalization of the Dirac cone in BaNiS₂ . This phenomenon is purely provoked by the electronic excitation and is stabilized by the interplay between the electrons and phonons. Moreover, by applying various pump-probe techniques (XFEL-based tr-XRD and tr-Reflectivity) we also explored the out-of-equilibrium phases of the prototype Mott-Hubbard material (V₁₋ₓMx)₂O₃ in different parts of its phase diagram. Our results show a transient non-thermal phase developing immediately after ultrafast photoexcitation and lasting few picoseconds in both metallic and insulating phases. This transient phase is followed by a structural distortion that corresponds to a lattice hardening and is marked by a “blue shift” of the A₁g phonon mode. These results underline the importance of the orbital filling as well as the strong effect of the selective electron-lattice coupling in the strongly correlated materials
40
Akcaoglu, Fehmi Umit. "Investigating The Effect Of Deformation And Annealing Texture On Magnetic Anisotropy In Low-c Steel Sheets By Magnetic Barkhausen Noise Method." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615569/index.pdf.
Full textAbstract:
Deformation and annealing texture in the cold rolled low carbon steels is important for sheet metal forming operations and service performance. The aim of this study is to non-destructively investigate the effect of texture on magnetic anisotropy. Various samples having different textures and residual stress states, due to different % reduction in thickness, annealing and stress relieving treatment, were prepared. Texture maps were obtained by Magnetic Barkhausen noise measurements performed with 100 steps between the ranges of 00-3600 on the surface. Microstructure investigation by optical &scanning electron microscopy
hardness and tension tests were performed
and texture was determined by X-Ray diffraction method. The results were compared, evaluated and discussed to establish relationship between texture and magnetic Barkhausen Noise emission.
41
Waller, Annalu. "Implementing linguistic text anticipation in a writing device for the disabled." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/26608.
Full textAbstract:
The advent of the microcomputer has provided the severely handicapped with the means to create text. Instead of using a keyboard, the disabled typist is able to scan and select linguistic items with an appropriate input switch. The resulting communication rate is, however, prohibitively slow for writing and impractical for conversation. A variety of techniques is used to improve this rate and range from static letter matrices to more sophisticated methods in which words and phrases are anticipated. Although many anticipatory methods claim to be linguistically based, most, if not all, depend solely on letter and word frequency statistics. A series of phonological rules can be used to anticipate the letter structure of most English words. This linguistically based system reflects a degree of "intelligence" not present in other anticipatory writing systems. To evaluate and compare the new system with several existing techniques in practice, a programmable evaluation system has been developed on an IBM-compatible personal computer using the Artificial Intelligence language, LISP. Different communication strategies are transcribed into rulebases which serve as input to the software. The core program then executes the particular system under consideration. Input text can be processed in either manual or simulation mode and an evaluation report is generated when the session ends. The characteristics of efficient communication systems are introduced as a basis for this dissertation, after which the development and application of a linguistic anticipatory writing system is described. The design of the evaluation software is documented and the successful implementation of the various communication systems is discussed.
42
Johnstone, Patricia Lynne. "The process and organisational consequences of new artefact adoption in surgery." Thesis, Electronic version, 2001. http://hdl.handle.net/1959.14/3905.
Full textAbstract:
Thesis (PhD)--Macquarie University, Macquarie Graduate School of Management, 2001.Bibliography: leaves 288-310.
Introduction -- Introduction to research problem and methodology -- Study context -- Theoretical framework - Review of the literature -- Study design and methods -- Study sites, surgical procedures, and labour input to surgical production -- New intra-operative artefacts: goals, choices and consequences -- Conclusion.
Surgical technologies since the late 1980s have undergone substantial innovations that have involved ...the adoption of new machines, instruments, and related surgical materials... referred to throughtout this thesis as intra-operative artefacts... typically represents a commitment of substantial financial resources by the hospitals concerned. However, little is documented about the process whereby the decisions are made to adopt new intra-operative artefacts, and no previous research appears to have explored the work-related consequences of new intra-operative artefact adoption within operating theatre services. This thesis explores the reasons why new intra-operative artefacts are adopted, how the decisions are made, who are the participants in the decsion process and what are the expected and actual organisational consequences of new intra-operative artefact adoption.
Electronic reproduction.
xii, 347 leaves, bound :
Mode of access: World Wide Web.
Also available in print form
43
DOMIENIKAN, CLAUDIO. "Desenvolvimento de um espectrômetro de correlação angular gama-gama perturbada com seis detectores de BaF2 e estudo de interações hiperfinas em composto intermetálico LaMnSi2." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26948.
Full textAbstract:
Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-22T16:42:56Z
No. of bitstreams: 0Made available in DSpace on 2016-12-22T16:42:56Z (GMT). No. of bitstreams: 0
Neste trabalho foi desenvolvido um Espectrômetro de Correlação Angular Gama- Gama Perturbada Diferencial em Tempo (CAP) constituído por seis detectores cintiladores de BaF2, para realização de medidas de interações hiperfinas (campo hiperfino magnético e gradiente de campo elétrico) em diversos materiais e propiciar estudos na área da física da matéria condensada. O espectrômetro desenvolvido possui um sistema de aquisição não convencional em comparação aos demais equipamentos destinados a medidas de CAP. Ao invés do tradicional Analisador Multicanal (MCA), este espectrômetro utiliza um sistema de aquisição de dados constituído, basicamente, por um Conversor Analógico Digital (ADC) rápido, uma placa digital (I/O) convencional e um roteador construído no laboratório de Interações Hiperfinas (LIH) do IPEN. Este versátil e eficiente sistema, controlado por um software também criado no LIH em LabVIEW, permite a geração simultânea de 30 espectros de coincidências γ - γ atrasadas, número superior em comparação aos 12 espectros do antigo espectrômetro de quatro detectores. Além de medidas de linearidade, resolução em tempo e tempo morto, o funcionamento e o desempenho do espectrômetro foram comprovados através de medidas de CAP utilizando os núcleos de prova 111In -> 111Cd e 181Hf -> 181Ta, cujos resultados são bem conhecidos da literatura. Foram feitas medidas de interação quadrupolar do 181Ta em háfnio metálico e do 111Cd em cádmio metálico, e de campo hiperfino magnético do 111Cd e do 181Ta em níquel. Os resultados destas medidas se mostraram em concordância com a literatura. Adicionalmente foram realizadas medidas inéditas de interações hiperfinas magnéticas no composto intermetálico LaMnSi2 utilizando os núcleos de prova 111Cd e 140Ce. As medidas foram realizadas na faixa de temperatura de 10 K a 400K. No caso das medidas utilizando a sonda 111In -> 111Cd, os resultados mostram uma variação do campo magnético com a temperatura que segue a função de Brillouin. Já no caso das medidas com o núcleo de prova 140La -> 140Ce, o resultado apresentou um comportamento anômalo do campo hiperfino em função de temperatura. Os resultados evidenciam uma forte hibridização da banda 4f do Ce com a banda 3d do Mn, fato verificado e estudado em trabalhos anteriores com compostos semelhantes.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
44
Alata, Romain. "Instrumentation pour l'astronomie et métrologie à l'aide de MOEMS." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0367.
Full textAbstract:
Les systèmes micro-opto-électro-mécaniques (MOEMS) représentent un atout considérable pour les technologies de demain et démontrent régulièrement leur capacité d'innovation dans tous les domaines de recherches. L'astronomie en profite déjà à travers l'optique adaptative et leur versatilité a récemment permis de développer un nouveau spectro-imageur BATMAN qui verra sa première lumière au Telescopio Nazionale Galileo (TNG) à La Palma (Iles Canaries). Le code de contrôle du MOEMS permettant l'automatisation de l'acquisition des spectres a été le point de départ de mon travail au LAM.La partie principale de ce manuscrit traite d'une seconde application imaginée en associant les MOEMS à un matériau photochromique développé à Polytecnico di Milano (Italie) qui peut prendre deux états différenciés par leur transparence. Le MOEMS, initialement utilisé pour la projection d'image, permet de moduler la dose d'énergie lumineuse projeté sur la plaque photochromique qui répond en s'éclaircissant progressivement. Ce procédé permet donc d'enregistrer des images en niveau de gris sur la plaque et notamment des hologrammes générés par ordinateur (CGH) utilisés en métrologie optique. Actuellement, les CGHs utilisés sont binaires, mais notre procédure permet d'enregistrer des CGHs quantifiés en amplitude avec une résolution de 13,68 µm et une précision inférieure à 1% en terme de transparence malgré un éclairage peu homogène. La quantification des CGHs de type Fresnel et Fourier ont été calculés, réalisés et testés avec succès. Deux nouveaux algorithmes de Fourier ont étaient imaginés, réalisés et ont montrés des performances très supérieurs au code usuel de Lee qui est un codage binaireMicro-opto-electro-mecanical systems (MOEMS) are primordial tools for future applications in several scientific fields as telecommunications or image display. Astronomy takes also advantage of their great adaptatbility thanks to the development of adaptative optics; a new spectro-imager called BATMAN has recently been develloped to be installed at Telescopio Nazionale Galileo (TNG) in the Canaries Islands. The control of the MOEMS allowing computerizing this processus has been the starting point of my work at the LAM.The main part of this manuscript deals with another application conceived thanks to the association of the characteristics of MOEMS and photosensitive materials developed at Politecnico di Milano (Italy). These materials can be put in two states differentiated by their transparency. The MOEMS, initially used to display images, allows controlling the dose of light projected on the photocrhomic plate which reacts by becoming more and more transparent. This process permit to record Computer Generated Holograms (CGHs) in grayscale which are used in optical metrology. Today, binary CGHs are used but our process allows to record amplitude quantified CGHs with a resolution of 13.68 µm and a precision better than 1% in term of transparency, even with a non homogeneous illumination beam. Comparative studies have shown advantages of quantified CGHs of Fresnel and Fourier families. Two new Fourier algorithms have been conceived thanks to use of the third dimension offered by the control of the transparency. They have been realized and tested succesfully, and have shown much better performances than the current binary coding, so called Lee algorithm
45
Jenne, Kirk E. "Acoustic cymbal transducers-design, hydrostatic pressure compensation, and acoustic performance." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FJenne.pdf.
Full textAbstract:
Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, March 2004.Thesis advisor(s): Thomas R. Howarth, Dehua Huang. Includes bibliographical references (p. 67-69). Also available online.
46
Assumpção, Flora Romanelli. "A natureza e o fantástico através da experiência visual." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/27/27159/tde-24112014-150504/.
Full textAbstract:
Este projeto artístico equivalente à dissertação para o mestrado em poéticas visuais é composto pela documentação do processo criativo, que é em si o mestrado em poéticas visuais, e por uma pequena seleção de fotogravuras originais da série \'Pequeno Compêndio dos Mares\'. A documentação consiste em três partes: primeira, registro de obras e exposições já realizadas e obras em processo; segunda, notas visuais e de texto; e última, uma seleção de trabalhos precedentes ao período do mestrado. A organização desta documentação do processo artístico foi feita priorizando o conjunto das imagens e considerando a linguagem visual como uma linguagem diversa e do mesmo valor da verbal, pois que assim como a palavra, o visual opera através de raciocínios intelectuais e sensíveis - e pode estar na universidade sendo debatido por artistas que trabalham com esta linguagem, medido dentro das particularidades da visualidade. Portanto apresento o registro e as obras materializadas como parte de um processo onde reflexão e fazer são o mesmo ato criativo e cuja complexidade intelectual existe desvinculada da necessidade da articulação pela palavra e independente de uma tese pré-formulada verbalmente, os textos aqui cumprem outra função: relacionam interesses, técnicas e influências temáticas de outras áreas do conhecimento.This artistic project, equivalent to the Master dissertation in visual arts, is composed by the documentation of the creative process, which is itself the Master degree in Visual Arts, as well as a small selection of photoengraving originals entitled \"Small Compendium of the Seas\". The documentation consists in three parts: first, art works and record of past exhibits and works in progress; second, visual and text notes; and last, selection of works preceding the period of Masters in Visual Arts. The organization of the documentation of the artistic process was made by prioritizing the body of work and considering the visual language as a diverse language but with the same legitimacy of verbal language, as well to the word, the visual knowledge operates through intellectual and sensible reasoning - and may be in the university being debated by artists who work with this language, measured within the particularities of visuality. Therefore I present the record and the materialized art works as part of a process where thinking and doing are the same creative act and in which intellectual complexity exists detached from the necessity of articulating word and independent of a pre-formulated verbal thesis, the texts here have another function: related interests, techniques and thematic influences from other areas of knowledge.
47
Pereira, Gabriel Kalil Rocha. "EFEITO DO DESGASTE COM INSTRUMENTOS DIAMANTADOS E DA DEGRADAÇÃO A BAIXAS TEMPERATURAS NO COMPORTAMENTO MECÂNICO DE UMA CERÂMICA Y-TZP." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/6139.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorObjectives: (1) Compare the effects of grinding on a Y-TZP ceramic executed by diamond discs and diamond burs (with similar grit sizes) in the micromorphology of surface, phase transformation (t®m), flexural strength and structural reliability (Weibull analysis), (2) evaluate the effect of LTD (low-temperature degradation) in the outcomes mentioned above. Methods: Three hundred and sixty discs (15mm x 1,2 mm) of Y-TZP were made according to ISO 6872 2008 for flexural strength determination on ceramic materials and sintered according to the manufacturer`s instructions, than they were divided into groups according to two factors in study: surface treatment - 5 levels (without treatment, extra-fine diamond bur, 600-grit diamond disc, coarse diamond bur and 120-grit diamond disc) and LTD on 2 levels (with and without). For grinding with diamond discs a polishing machine was employed, while for grinding with diamond burs a device was employed to assure the perpendicularity between diamond tip and abrading surface, that way the abrasion movements and the applied pressure were standardized. The LTD was induced in an autoclave at 134ºC under 2 bar for 20 hours. Results: Our findings support that LTD although promoted increase in mphase content and micromorphological alterations did not promoted decrease in zirconia s mechanical properties, grinding at a first moment did not affected too, but when ground Y-TZP was submitted to the LTD effects, the defects introduced by grinding could be detrimental to the material`s resistance. From a methodological point of view, diamond discs should not be employed to simulate clinical abrasion performed with diamond burs on Y-TZP ceramics. Conclusion: Thus grinding of zirconia should be avoided and when it was really necessary tools with low grit sizes should be employed.
Objetivos: (1) Comparar os efeitos do desgaste da cerâmica Y-TZP gerados por lixas e pontas diamantadas (com granulações semelhantes) na micromorfologia da superfície, na transformação de fase (t®m), na resistência à flexão biaxial e confiabilidade estrutural (análise de Weibull), (2) Avaliar o efeito da LTD nos desfechos citados acima. Métodos: Trezentos e sessenta discos (15 mm x 1,2 mm) de Y-TZP foram confeccionados segundo as instruções da ISO 6872 2008 para ensaios de flexão em material cerâmico e sinterizados de acordo com as recomendações do fabricante, posteriormente foram divididos em grupos, de acordo com dois fatores em estudo: tratamento de superfície da cerâmica - 5 níveis (sem tratamento, disco de granulação 120, ponta diamantada de granulação super grossa, disco de granulação 600, ponta diamantada extra fina) e LTD - 2 níveis (sem e com). Para abrasão com lixas de diferentes granulações foi utilizada uma politriz, enquanto que para a abrasão com as pontas diamantadas foi utilizado um dispositivo que garantiu a perpendicularidade da ponta diamantada à superfície da amostra, padronizando os movimentos de abrasão e a pressão aplicada. A LTD foi realizada em autoclave sob 134° C à 2 bar por 20 horas. Resultados: Nossos achados suportam que a LTD embora promovesse aumento de fase monoclínica e alterações micromorfológicas não causou perda de propriedades mecânicas da zircônia, o desgaste em primeiro momento também não promoveu, mas quando esta superfície foi submetida aos efeitos da LTD, os defeitos introduzidos pelo desgaste podem ser prejudiciais a resistência do material. Sob um ponto de vista metodológico o uso de discos diamantados não deve ser empregado para simular o desgaste executado clinicamente com pontas diamantadas. Conclusão: Dessa forma o desgaste da superfície da zircônia deve ser evitado e quando necessário deve ser realizado com instrumentos de menor granulação.
48
Dufay, Basile. "Optimisation d'un magnétomètre à haute sensibilité à base de Magnéto-Impédance Géante (MIG)." Phd thesis, Université de Caen, 2012. http://tel.archives-ouvertes.fr/tel-00747006.
Full textAbstract:
L'effet magnéto-impédant géant (MIG) traduit la forte variation de l'impédance d'un conducteur ferromagnétique soumis à une variation de champ magnétique externe. L'objectif de ce travail de thèse est l'optimisation des performances en bruit d'un magnétomètre à MIG. Ces dernières limitent ultimement le plus petit champ magnétique mesurable. Ainsi, nous présentons l'étude des propriétés physiques du matériau permettant d'évaluer la sensibilité propre de l'élément sensible à l'aide d'un modèle simpli fié. L'originalité de cette étude réside dans la prise en compte de la sensibilité exprimée en V/T, liée à l'amplitude d'excitation optimale, comme critère de performance. A fin d'accroître encore cette sensibilité, les dispositifs MIG sont associés à une bobine de capture. La réponse en champ du quadripôle ainsi constitué est modélisée. La capacité parasite de la bobine, identifi ée comme un facteur limitant, implique alors une fréquence d'excitation optimale propre à chaque élément sensible. Finalement, une modélisation globale des performances en bruit, intégrant de plus le conditionnement électronique, est développée. Celle-ci permet de prédire et d'analyser les performances en fonction des conditions de mise en oeuvre, notamment vis-à-vis du type de démodulation. Ces résultats valident l'intérêt de la structure quadripôle et apportent un éclairage important sur le choix du point de fonctionnement en champ statique du capteur. Ce travail permet alors de réaliser un magnétomètre optimisé. Il affi che des performances très honorables avec un niveau de bruit équivalent en champ inférieur à 1 pT/sqrt(Hz) en zone de bruit blanc.
49
Ortega-Bucio, de Garnica Lydia Gabriela. "Développement d'une cellule triaxiale haute pression pour essais sur roches poreuses saturées : application aux grès." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10054.
Full textAbstract:
Le but du travail presente dans ce memoire est la contribution au developpement d'une cellule triaxiale pour des essais sur roches poreuses saturees. Les roches etudiees sont principalement des gres de structure interne differente, sur lesquels on a effectue tout d'abord des essais classiques d'identification pour connaitre leurs proprietes physiques et mecaniques. Dans un deuxieme temps, ces roches ont ete soumises a differents chemins de contraintes, qui correspondent a des essais experimentaux speciaux (essais de compressibilite, hydrostatiques et deviatoires en conditions drainees et non drainees). Le memoire presente s'articule en trois parties: 1 - une etude bibliographique sur des proprietes geotechniques des gres et une introduction aux parametres de l'interaction fluide-squelette, 2 - une presentation du materiel mis au point et des materiaux utilises pour le developpement des essais, 3 - les resultats experimentaux et leur exploitation pour une meilleure connaissance des parametres mecaniques du comportement des roches poreuses saturees
50
Brasiliano, Diego Augusto Paixao. "Etude et réalisation d'une ADR spatiale 4 K - 50 mK." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY028/document.
Full textAbstract:
Cette thèse porte sur la recherche et l'amélioration de cryoréfrigérateurs à désaimantation adiabatique (ADR) pour la gamme 4 K - 50 mK. Ce refroidissement à 50 mK permettra de répondre aux besoins de réfrigération des détecteurs les plus sensibles envisagés pour les instruments des missions d'astrophysique. Ce réfrigérateur doit être efficace et de masse optimisée.Les axes clefs de ce travail sont la mise au point d’une méthode d’identification de réfrigérants magnétiques de haute performance et l'étude d’interrupteurs thermiques efficaces. Parmi les matériaux étudiés, le YbGG (Yb3Ga5O12) a été identifié comme un excellent réfrigérant potentiel pour la gamme 1.5 K - 0.4 K, confirmé par sa caractérisation expérimentale. Le travail sur les interrupteurs thermiques à gaz d'échange a permis de supprimer ou de réduire de façon importante des effets de courts-circuits thermiques transitoires parasites, lesquels apparaissent dans les conditions particulières d’utilisation de ce type de cryocooler. Finalement, un démonstrateur de cryoréfrigérateur constitué de 3 étages d’ADR en série, adapté pour les besoins des futures missions spatiales, a été dimensionné et fabriquéHighly sensitive detectors required for astrophysics missions demand temperatures of about 50 mK to operate with the targeted sensitivity. This PhD work is dedicated on the research and development of Adiabatic Demagnetization Refrigerators (ADR) for space in the 4 K - 50 mK range. In particular, this cryocooler is required to be efficient with optimized mass.The key points of this work are the development of a method allowing the identification of highly efficient paramagnetic materials and the improvement of thermal heat switches. Among the material studied, YbGG (Yb3Ga5O12) was identified to have a great potential as a magnetic refrigerant in the 1.5 K - 0.4 K range, which was confirmed by its characterization. Transient thermal short circuits may appear on the gas-gap thermal switches under the working conditions of this cryocooler. This study allowed us to suppress or to considerably attenuate this effect. Finally, a cryocooler prototype consisting of 3 ADR stages was designed and built