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Dissertations / Theses on the topic 'Photographic mechanics'
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1
Singh, Ajit 1951. "Photographic evaluation of blast fragmentation." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63380.
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Valenzuela-Escobedo, Sergio. "Mänk’áčen : mécanique photographique, mysticisme et superstition chez les peuples originaires d'Amérique du Sud." Thesis, Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0328.
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Toumayacha Alakana : cette expression populaire est à l’origine de ma recherche : elle signifie « regarder la tête couverte d’un voile ». C’est ainsi que les Fuégiens ont nommé l’acte de photographier au XIXe siècle, quand ils ont vu les premiers appareils photographiques avec les opérateurs qui ont débarqué en Amérique dès 1840. Quels noms les peuples locaux ont-ils donnés à ces nouvelles images-objets ? Comment cet outil inconnu a-t-il été perçu ? Que signifie d’être regardé la tête couverte d’un voile ? C’est par un changement de focale et une inversion du point de vue que cette thèse approche l’étude de l’acte photographique en Amérique du Sud. La compréhension de la photographie peut-elle changer si on l’aborde en l’étudiant à partir du regard que ces peuples portent sur l’appareil photographique ?Dire que les Amérindiens ne veulent pas être photographiés, en particulier parce qu’on « va leur voler leur âme », est un mythe colonial ; cette croyance occidentale donne de la valeur aux images que les explorateurs rapportent. La question du refus des appareils est beaucoup plus complexe et variée : la résistance peut porter sur la prise de vue, sur la circulation de l’image de soi, sur le caractère unilatéral de la transaction, sur l’incompréhension de l’appareil comme sur des conséquences politiques et spirituellesToumayacha Alakana : this popular expression lays at the root of my research. It means “to look with a veiled head”. It is how the Fuegians named the act of photographing in the19th century, when they saw their first cameras, as operators came to America around 1840.What names did native people give to those new images-cum-objects ? How was that unknown device perceived ? What does it mean to be looked at by a veiled head ? My doctoral research offers a shift of of focus and point of view on the act of photography in South America. Can our understanding of photography change if we take native peoples’ perspective on the camera as a starting point ?The idea that native people do not want to be photographed, especially because it would be “stealing their souls”, is a colonial myth. This western belief gave value to the images brought back by explorers. The reasons behind refusing the camera are much more complex and diverse : they can be about the camera angle, the circulation of the image of the self, the one-sided nature of the transaction, the lack of understanding of the device, or political and spiritual considerations
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Kubaczyk, Daniel Mark. "Photographic lens manufacturing and production technologies." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69779.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 55-56).
An investigation was conducted to determine the methods and processes required for the manufacture of photographic objective lenses. Production of photographic lenses requires incredible precision in the melting, mixing, molding and machining of optical glass. Manual inspection methods are required to ensure optimum quality and to avoid inclusion of defects in glass. Manual assembly procedures are required to ensure delicate operation of glass elements but contribute significantly to the consumer expense of these lenses. Newly developed technologies in the field of lens machining are discussed in terms of commercial advances and scientific advances. Companies like Canon have sought greater automation in pre-assembly procedures as well as a reduction in the number of machining steps. New advances including precision machining of aspherical lenses, fluid-jet polishing and magnetorheological finishing are pushing the boundaries of lens machining and its characteristic surface roughnesses to depths not seen before.
by Daniel Mark Kubaczyk.
S.B.
4
Vernon, Kris. "A photographic probe for wet steam." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/30933/.
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The work carried out during this engineering doctorate degree has led to significant advances in the application of photographic measurement techniques to the characterisation of coarse water in wet steam flow, with particular emphasis on the development of a compact measurement probe suitable for application in a low-pressure steam turbine. Through the application of pulsed LED illumination for the first time in a compact probe, photographs at high magnification with excellent resolution are obtainable at significantly shorter exposure times than others reported in the literature. This has the advantage of reducing motion blur enabling reliable quantitative analysis to take place. Secondary to this, the coupling of high magnification, high resolution photography with pulsed LED illumination has been shown to provide a powerful research tool for flow visualisation across a range of applications, at an order of magnitude lower cost than commercial solutions employing pulsed laser illumination for the same purpose. This builds on the work of others elsewhere in the literature, but again has been proven at shorter exposure times enabling higher magnification with reduced motion blur. Finally a flexible optical test rig has been designed and manufactured, to act as an experimental test-bed for both photographic and phase-Doppler measurements on two-phase steam and air-water sprays. Phase-Doppler anemometry measurements have been performed on an accelerated jet of two-phase steam in order to perform size and velocity measurement of liquid droplets. This acts as a proof-of-concept for the technique in wet steam given the appropriate optical access. In addition phase-Doppler measurements of an air-atomising water nozzle were used as a validation data set to assess the accuracy and reliability of quantitative data from the photographic probe. In this case quantitative data was extracted from the images through application of a custom-designed image processing algorithm, designed to extract droplet size and velocity information from double-exposure droplet images. In general agreement is good within 10-15% of the PDA measurements. Photographic and PDA measurements have also been taken of an LP spray nozzle, as used in the Alstom model steam turbine test facility. These tests have demonstrated significant differences in the spray characteristics when spraying into air and into vacuum conditions. This provides useful insight for the positioning and application of these spray nozzles in a steamturbine environment.
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Kiyanda, Charles Basenga. "Photographic study of the structure of irregular detonation waves." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98981.
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Detonation waves in gaseous reactive mixtures have been known to exhibit multidimensional structure since the 1950's. The interaction of shocks and presence of unsteady triple shock interactions in the detonation structure give rise to the detonation cell, the size of which is determined by the reactive mixture and initial conditions. Detonable gaseous mixtures have been classified as regular or irregular, depending on their behavior in particular experimental conditions. The main combustion mechanisms in the structure of irregular mixtures have not yet been positively identified. The structure of detonation waves in an irregular mixture of stoichiometric methane and oxygen is observed using non-intrusive visual diagnostics. Framing schlieren, streak schlieren and framing self-luminous imaging were used, yielding, respectively, an instantaneous measure of the density gradient, a time evolution of the density gradients and a record of the regions of high luminosity. Regions of high luminosity correspond qualitatively to regions of high chemical reaction. Pockets of high density gas were observed behind the lead shock surface. Light emission was observed, using framing self-luminous imaging, at the edges of these pockets indicating the pockets burned primarily at the edges. The amount of mass burned in one such pocket was found to be 40% of the total mass burned in one cell cycle. The induction time of a particle undergoing shock compression was calculated. The cases of constant properties behind the shock and of a decaying blast followed by expansion waves were considered as characteristic induction times of shock-induced combustion. Both measures of induction time were found to be longer than the typical time scale of a particle burning in one of the observed pockets. Furthermore, the coincidence of light emission with the edges of the pocket of unburned gas and the long time scales involved indicate the burning mechanism of this unburned pocket to be turbulent diffusion rather than shock compression.
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Zhao, Hang Ph D. Massachusetts Institute of Technology. "Computational photography with novel camera sensors." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103458.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 57-62).
In this thesis, two computational camera designs are presented. They target two major goals in computational photography. high dynamic range (HDR) imaging and image superresolution (SR). HDR imaging refers to capturing both bright and dark details in the scenes simultaneously. A modulo camera does not get saturated during exposure, enabling HDR photography in a single shot without losing spatial resolutions. The second camera achieves image super-resolution with its non-conventional pixel design. It is shown that recording multiple images with a sensor of asymmetric sub-pixel layout increases the spatial sampling capability compared to a conventional sensor. Both proposed camera designs are the combination of novel imaging sensors and image recovering algorithms. Their potential applications include photography, robotics, and scientific research. Theoretical analyses and experiments are performed to validate our solutions.
by Hang Zhao
S.M.
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Mo, Ning. "Mechanical characterisation of bone with laser speckle photography." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339170.
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Young, Eleanor Dawn, and ellie@goldstreetstudios com au. "Mechanisms of Controlling Colour and Aesthetic Appearance of the Photographic Salt Print." RMIT University. Applied Science, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080901.142948.
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Abstract The salt print is an important part of photography, both in its historic value and in the tonal range it can provide. This tonal range is greater than any other photographic printing process available to date attributed to the inherent masking ability of the metallic silver. However the intrinsic production problems have made it a 'forgotten' process. There are five key problems. 1. The difficulties in achieving the potential extensive tonal range. 2. The varying colour of the print. 3. Staining that appears in the print, during and after processing. 4. Instability and longevity of the salt print. 5. Contradictory and inaccurate information in material published on the salt print. Although the emphasis of the research is on exploring and controlling the colour and tonal range, the staining problems and stability of the print are also addressed. The materials used for contact negatives today vary in both capture and output, from analogue film processed in the traditional wet darkroom to a variety of transparent film printed from digital files. Inadequate density and tonal range can affect all types of negatives. To provide sufficient exposure time for the salt prints extended tonal range adjustments to the negative were necessary. These long exposures then converted sufficient silver salts to the image making metallic silver, utilising the intrinsic self-masking process. Ultimately this research has uncovered ways to control colour and tonal range and certain aesthetic qualities of the salt print, while simultaneously resolving some of the conflicts in published information. Accurate and consistent methods of processing eliminate staining, providing some stability to the print. The activities and steps carried out to make a salt print are manual; precise duplication is therefore almost unattainable. Nevertheless, although tests on a densitometer may display numeric differences, visual differences are barely noticeable.
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Sjödahl, Mikael. "An electronic speckle photography system for in plane deformation measurements." Licentiate thesis, Luleå tekniska universitet, Strömningslära och experimentell mekanik, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16973.
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Street, Matthew W. (Matthew William) 1973. "Quick response inventory replenishment for a photographic material supplier." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/84518.
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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2001.Includes bibliographical references (leaf 60).
by Matthew W. Street.
S.M.
M.B.A.
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Johnson, Peder. "Dua-beam digital speckle photography : strain field measurements in aerospace applications." Licentiate thesis, Luleå tekniska universitet, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26085.
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Buckley, Craig. "Photomosaicing and automatic topography generation from stereo aerial photography." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/790.
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Mizo, Viktor R. "Investigation of inertia controlled bubble departure mechanism in subcooled flow boiling using high speed photography /." Online version of thesis, 1995. http://hdl.handle.net/1850/12084.
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Buck, Dietrich. "Mechanics of Cross-Laminated Timber." Licentiate thesis, Luleå tekniska universitet, Träteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68729.
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Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. Wood is a sustainable, renewable material, and the increasing use of wood in construction contributes to its sustainability. Multi-layer wooden panels are one type of engineered wood product used in construction. There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. Assembly techniques considered in the earliest stages of this research work were laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. Cross-laminated timber (CLT) was found to offer some advantages over these other techniques. It is cost-effective, not patented, offers freedom of choice regarding the visibility of surfaces, provides the possibility of using different timber quality in the same panel at different points of its thickness, and is the most well-established assembly technique currently used in the industrial market. Building upon that foundational work, the operational capabilities of CLT were further evaluated by creating panels with different layer orientations. The mechanical properties of CLT panels constructed with layers angled in an alternative configuration produced on a modified industrial CLT production line were evaluated. Timber lamellae were adhesively bonded in a single-step press procedure to form CLT panels. Transverse layers were laid at a 45° angle instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle. Tests were carried out on 40 five-layered CLT panels, each with either a ±45° or a 90° configuration. Half of these panels were evaluated under bending: out-of-plane loading was applied in the principal orientation of the panels via four-point bending. The other twenty were evaluated under compression: an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. Quasi-static loading conditions were used for both in- and out-of-plane testing to determine the extent to which the load-bearing capacity of such panels could be enhanced under the current load case. Modified CLT showed higher stiffness, strength, and fifth-percentile characteristics, values that indicate the load-bearing capacity of these panels as a construction material. Failure modes under in- and out-of-plane loading for each panel type were also assessed. Data from out-of-plane loading were further analysed. A non-contact full-field measurement and analysis technique based on digital image correlation (DIC) was utilised for analysis at global and local scales. DIC evaluation of 100 CLT layers showed that a considerable part of the stiffness of conventional CLT is reduced by the shear resistance of its transverse layers. The presence of heterogeneous features, such as knots, has the desirable effect of reducing the propagation of shear fraction along the layers. These results call into question the current grading criteria in the CLT standard. It is suggested that the lower timber grading limit be adjusted for increased value-yield. The overall experimental results suggest the use of CLT panels with a ±45°-layered configuration for construction. They also motivate the use of alternatively angled layered panels for more construction design freedom, especially in areas that demand shear resistance. In addition, the design possibility that such 45°-configured CLT can carry a given load while using less material than conventional CLT suggests the potential to use such panels in a wider range of structural applications. The results of test production revealed that 45°-configured CLT can be industrially produced without using more material than is required for construction of conventional 90°-configured panels. Based on these results, CLT should be further explored as a suitable product for use in more wooden-panel construction.External cooperation: Martinson Group AB and Research Institutes of Sweden (RISE)
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Bhattacharjee, Rohit Ranjan. "Experimental Investigation of Detonation Re-initiation Mechanisms Following a Mach Reflection of a Quenched Detonation." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24933.
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Detonation waves are supersonic combustion waves that have a multi-shock front structure followed by a spatially non-uniform reaction zone. During propagation, a de-coupled shock-flame complex is periodically re-initiated into an overdriven detonation following a transient Mach reflection process. Past researchers have identified mechanisms that can increase combustion rates and cause localized hot spot re-ignition behind the Mach shock. But due to the small length scales and stochastic behaviour of detonation waves, the important mechanisms that can lead to re-initiation into a detonation requires further clarification.
If a detonation is allowed to diffract behind an obstacle, it can quench to form a de-coupled shock-flame complex and if allowed to form a Mach reflection, re-initiation of a detonation can occur. The use of this approach permits the study of re-initiation mechanisms reproducibly with relatively large length scales. The objective of this study is to experimentally elucidate the key mechanisms that can increase chemical reaction rates and sequentially lead to re-initiation of a de-coupled shock-flame complex into an overdriven detonation wave following a Mach reflection.
All experiments were carried out in a thin rectangular channel using a stoichiometric mixture of oxy-methane. Three different types of obstacles were used - a half-cylinder, a roughness plate along with the half-cylinder and a full-cylinder. Schlieren visualization was achieved by using a Z-configuration setup, a high speed camera and a high intensity light source.
Results indicate that forward jetting of the slip line behind the Mach stem can potentially increase combustion rates by entraining hot burned gas into unburned gas. Following ignition and jet entrainment, a detonation wave first appears along the Mach stem. The transverse wave can form a detonation wave due to rapid combustion of unburned gas which may be attributed to shock interaction with the unburned gas. Alternatively, the Kelvin-Helmholtz instability can produce vortices along the slipline that may lead to mixing between burned-unburned gases and potentially increase combustion rates near the transverse wave. However, the mechanism(s) that causes the transverse wave to re-initiate into a detonation wave remains to be satisfactorily resolved.
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Hellström, Lisbeth. "Fracture processes in wood chipping." Licentiate thesis, Mid Sweden University, Department of Natural Sciences, Engineering and Mathematics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-7827.
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In both the chemical and mechanical pulping process, the logs are cut into wood chips by a disc chipper before fibre separation. To make the wood chipping process more efficient, one have to investigate in detail the coupling between theprocess parameters and the quality of the chips. The objective of this thesis is to obtain an understanding of the fundamental mechanisms behind the creation of wood chips. Both experimental and analytical/numerical approaches have been taken inthis work. The experimental investigations were performed with an in‐house developed equipment and a digital speckle photography equipment. The results from the experimental investigation showed that the friction between the log and chipping tool is probably one crucal factor for the chip formation. Further more it was found that the indentation process is approximately self‐similar, and that the stress field over the entire crack‐plane is critical for chip creation. The developed analytical model predicts the normal and shear strain distribution. The analytical distributions are in reasonable agreement with the corresponding distributions obtained from a finite element analysis.
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Hellström, Lisbeth. "On the wood chipping process : a study on basic mechanisms in order to optimize chip properties for pulping." Doctoral thesis, Mittuniversitetet, Institutionen för naturvetenskap, teknik och matematik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11911.
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In both the chemical and mechanical pulping process, the logs are cut into wood chips by a disc chipper before fibre separation. To make the wood chipping process more efficient, one have to investigate in detail the coupling between process parameters and the quality of the chips. One objective of this thesis was to obtain an understanding of the fundamental mechanisms behind the creation of wood chips. Another objective with the thesis was to investigate whether it was possible to, in a way tailor the chipping process so as to reduce the energy consumption in a following mechanical refining process. Both experimental and analytical/numerical approaches have been taken in this work. The first part of the experimental investigations, were performed with an in-house developed chipping device and a digital speckle photography equipment. The results from the experimental investigation showed that the friction between the log and chipping tool is probably one crucial factor for the chip formation. Further more it was found that the indentation process is approximately self-similar, and that the stress field over the entire crack-plane is critical for chip creation. The developed analytical model predicts the normal and shear strain distribution and to be more specific, the model can predict the compressive stresses parallel to the fibre direction for an assumed linear elastic and orthotropic material. The analytical distributions were found to be in reasonable agreement with the corresponding distributions obtained from a finite element analysis. To be able to study the chipping process under realistic conditions, which for example means to use chipping rates representative for a real wood chipper, a laboratory chipper was developed. Details regarding the chipper and how to evaluate the force measurements are given together with an example of how the force on the cutting tool (the knife) varies with time during cutting. To investigate the influence of a certain chipping process parameter, the chips were after production in the laboratory chipper, refined in a pilot refiner during conditions optimized for TMP (thermomechanical pulp) and CTMP (chemithermomechanical pulp) processes. It was concluded that the details concerning the chip process had a large impact on e.g. the energy consumption in both first stage and second stage refining. Results showing this are given in this thesis.För både kemisk och mekanisk pappersmassa så tillverkas flis av trädstockar med hjälp av en skivhugg innan fibrerna separeras. För att göra flisningsprocessen mer effektiv, måste kopplingen mellan processparametrar och fliskvalitet studeras. Ett mål med denna avhandling är att ge fundamental kunskap om mekanismerna bakom bildandet av träflis. Både experimentella och analytiska/numeriska metoder har använts i detta arbete. De experimentella undersökningarna har gjorts med hjälp av egen utvecklad utrustning. Resultaten från den experimentella undersökningen visar att friktionen mellan stammen och flisningsverktyget har betydelse vid flisning. Vidare observerades det att inträngnings processen är approximativt självlik (self similar) och att det är spänningsfältet över hela sprickplanet som är kritiskt för bildandet av en flis. Den utvecklade analytiska modellen förutsäger normal- och skjuvspänningsfördelningen över sprickplanet och kan mer specifikt förutsäga den kompressiva belastning som verkar parallellt fiberriktningen i ett linjärt elastiskt och ortotropt material (trä). De analytiskt bestämda fördelningarna stämmer relativt väl överens med motsvarande fördelningar beräknad med finit element analys. För att kunna studera flisningsprocessen under realistiska förhållanden, vilket bl.a. betyder att skärhastigheter som är representativa för en verklig process skall användas, så utvecklades inom ramen för avhandlingsarbetet, en laboratoriesflishugg. Detaljer rörande flishuggen samt hur uppmätta lastsignaler skall utvärderas ges tillsammans med ett exmpel på hur kraften på skärverktyget (kniven) varierar under ett skärförlopp. Inverkan av en viss flisningsprocessparameter undersöktes genom att flis tillverkades i laboratorieflishuggen varefter de raffinerades i en pilotraffinör under förhållanden som var optimerade för TMP (termomekanisk massa) och CTMP (kemitermomekanisk massa) processerna. Det konstaterades att detaljer i flisningsprocessen hade stor inverkan på t.ex. energiåtgången i både första stegs – och andrastegsraffinering. Resultat som verifierar detta ges i avhandlingen.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Submitted. Paper 5: Submitted.
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Poilâne, Christophe. "CARACTÉRISATION MÉCANIQUE DES MATÉRIAUX EN FAIBLE ÉPAISSEUR PAR INTERFÉROMÉTRIE NUMÉRIQUE. APPLICATION AUX ESSAIS DE GONFLEMENT ET DE TRACTION." Phd thesis, Université de Franche-Comté, 1998. http://tel.archives-ouvertes.fr/tel-00326993.
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La thèse est consacrée à la caractérisation mécanique des films minces à l'aide de mesures de déplacements par voie optique et traitements numériques. Les domaines d'études sont d'une part les contraintes résiduelles et d'autre part l'essai de traction. Les moyens de mesure employés sont la projection de franges et la photographie numérique de speckle.La projection de franges permet de mesurer la carte des déplacement hors-plan. Elle est adaptée à la mesure des contraintes résiduelles dans les films minces par analyses de courbure et/ou essais de gonflement. On montre suite à trois études expérimentales :
1. la précaution à prendre dans l'utilisation de la formule de Stoney même pour des bicouches libre-libre (SiO2/Si) ;
2. la présence de flambage dans les membranes bicouches comprimées encastré-encastré (SiO2/Si) ;
3. un parfait accord entre essais de gonflement et essais de nano-indentation pour des films tendus (polimiide).
La photographie numérique de speckle permet de mesurer la carte des déplacements dans le plan. Elle est adaptée avec succès à un banc d'essais de traction conçu durant la thèse et spécialement dédié aux films minces. Un algorithme original de calcul a été développé pour obtenir une résolution subpixel. Les performances de l'algorithme sont comparées par des simulations et des expériences aux algorithmes classiques de corrélation. Sa rapidité et sa haute résolution permettent de calculer les cartes de déplacements en temps réel. Les déformations dans le plan en sont déduites et permettent le tracé des courbes contrainte/déformation puis le calcul du module d'Young E et du coefficient de Poisson v. Les matériaux choisis pour valider le banc d'essai sont le cuivre électrodéposé, matériaux ductile, puis le silicium monocristallin, matériaux fragile.
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Гарник, Ярослав Юрійович, and Yaroslav Harnyk. "Інформаційно-вимірювальна система пристрою для вимірювання довжини канатів з навивкою." Master's thesis, ТНТУ ім. І. Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33753.
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Розроблено інформаційно-вимірювальну систему для пристрою для вимірювання довжини канатів з навивкою. В даному дипломі було проведено розрахунок прижимного механізму та було здійснено вибір та розрахунок елементів конструкції приладу. Описаний вимірювальний пристрій, що здійснює комплексний контроль основних параметрів. Було описано процес визначення виду аналітичної залежності та її коефіцієнтів, Зроблено математичне дослідження руху циліндричного тіла зі зміщеним центром мас по похилій площині. Також у даній роботі проведено опис роботи та аналіз схеми електричної принципової та розроблено лістинг програми зчитування текучої довжини.An information-measuring system has been developed for a device for measuring the length of ropes with winding. In this diploma, the calculation of the clamping mechanism was performed and the design elements of the device were selected and calculated. The measuring device which carries out complex control of the basic parameters is described. The process of determining the type of analytical dependence and its coefficients was described. A mathematical study of the motion of a cylindrical body with a shifted center of mass on an inclined plane was made. Also in this work the description of work and the analysis of the scheme of electric basic and the listing of the program of reading of current length is developed.
ВСТУП 1 Аналітична частина 1.1 Патентний пошук і порівняльна характеристика пристроїв 1.2 Пристрій для вимірювання довжини рухаючого матеріалу 2 Основна частина 2.1 Вимоги до роботи приладу 2.2 Методи знаходження кроку кабеля 2.3 Розразунок прижимного механізму 2.4 Вибір і змащування рухомих вузлів 2.5 Кабельна тара, упаковка, маркування, транспортування і зберігання 2.6 Розрахунок похибок вимірювання 2.7 Метрологічний аналіз системи позиціонування 2.8 Економічні переваги пристрою нового обладнання 3 Науково-дослідна частина 3.1 Постановка задачі 3.2 Визначення виду аналітичної залежності і її коефіцієнтів 4 Спеціальна частина 4.1 Схеми керування виконавчим пристроєм 4.2 Вибір, розрахунок схеми включення давачів 4.3 Призначення і структура блоку керування 4.4 Опис роботи схеми 4.5 Програмне забезпечення 4.6 Блок-схема алгоритму роботи блоку керування та опис її роботи 4.7 Схема проходження сигналу 4.8 Лістинг програми зчитування текучої довжини 5 Охорона праці та безпека в надзвичайних ситуаціях 5.1 Охорона праці 5.1.1 Розрахунок місцевого освітлення для спроектованого пристрою 5.1.2 Використання і опис дії систем пожежогасіння, які використовують на підприємствах приладобудування ЗАГАЛЬНІ ВИСНОВКИ ДО КВАЛІФІКАЦІЙНОЇ РОБОТИ ПЕРЕЛІК ПОСИЛАНЬ ДОДАТКИ
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Grégoire, David. "Initiation, propagation, arrêt et redémarrage de fissures sous impact." Phd thesis, INSA de Lyon, 2008. http://tel.archives-ouvertes.fr/tel-00418626.
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Les risques liés à la propagation de fissures sous impact sont encore très difficiles à estimer. La détermination de critères de rupture dynamique uniquement à partir de résultats expérimentaux reste délicate. Ainsi la première étape pour valider des lois de propagation de fissures sous impact passe par le développement d'outils de simulation numérique. Depuis les années 1970, de nombreux codes de calcul mécanique ont été dédiés à l'étude de la propagation de fissures, notamment dans le cas du phénomène de fatigue. La principale difficulté consiste dans la nécessité de suivre la géométrie de la fissure au cours du temps. Ces dernières années, des méthodes alternatives basées sur la partition de l'unité ont permis une description implicite des discontinuités mobiles. C'est le cas de la méthode des éléments finis étendue (X-FEM) qui paraît particulièrement adaptée à la simulation de la propagation dynamique de fissures sous chargement mixte où les trajets de fissures ne sont pas connus a priori. Si ces outils numériques permettent maintenant de représenter l'avancée dynamique d'une fissure, les résultats numériques doivent être comparés à des résultats expérimentaux pour s'assurer que les lois introduites sont physiquement fondées. Notre objectif est donc de développer conjointement des techniques expérimentales fiables et un outil de simulation numérique robuste pour l'étude des phénomènes hautement transitoires que sont l'initiation, la propagation, l'arrêt et le redémarrage de fissures sous impact.Des expériences de rupture dynamique ont donc été réalisées sur du Polyméthacrylate de méthyle (PMMA) durant lesquelles la mixité du chargement varie et des arrêts et redémarrages de fissures se produisent. Deux bancs d'essais différents ont été utilisé, le premier basé sur la technique des barres de Hopkinson (ou barres de Kolsky), le second mettant en jeu un vérin rapide. Le PMMA étant transparent, la position de la fissure au cours de l'essai a été acquise grâce à des caméras rapides mais aussi en utilisant un extensomètre optique (Zimmer), habituellement dédié à la mesure de déplacements macroscopiques d'un contraste noir/blanc. L'utilisation de cet extensomètre pour suivre la fissure au cours de l'essai a permis d'obtenir une localisation très précise de la pointe de la fissure en continu, permettant ainsi l'étude des phases transitoires de propagation. Afin d'étudier le même phénomène dans des matériaux opaques comme les aluminiums aéronautiques (Al 7075), des techniques de corrélation d'images numériques ont été employées en mouchetant les éprouvettes impactées. De nouveaux algorithmes ont été développés afin de traiter les images issues d'une caméra ultra-rapide (jusqu'à 400 000 images par seconde).
Plusieurs géométries ont été envisagées afin d'étudier différents cas de propagation dynamique : initiation en mode I pur, initiation en mode mixte, propagation, arrêt, redémarrage, interaction entre deux fissures, influence d'un trou sur le trajet d'une fissure, branchement dynamique de fissures. Ces expériences ont ensuite été reproduites numériquement afin de valider les algorithmes et les critères de rupture choisis.
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Fernandes, Sandro Roberto. "Ferramenta de visão computacional para processos fotogramétricos." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=718.
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Nesta dissertação é apresentado o desenvolvimento de uma ferramenta computacional para o processamento de pares de imagens estereoscópicas obtidos por câmeras aéreas métricas e não métricas. O programa foi desenvolvido na linguagem C++ e foi utilizado a biblioteca OpenGL. O resultado obtido é uma imagem tridimensional de onde pode ser extraídas cotas de altura e formas de terreno. Estas imagens poderão ser usadas no estudo de áreas de risco em encostas.In this dissertation is presented the development of a computational tool for the processing of pairs of images estereoscópicas obtained by metric and not metric aerial cameras. The program was developed in the program language C++ and the library was used OpenGL. The result of the program is a three-dimensional image from where it can be extracted height quotas and land forms. These images can be used in the study of risk areas on slopes.
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Huang, Yong-Jian, and 黃詠健. "Developing a Professional Image Enhancement Mechanism Based on Contemporary Photograph Aesthetics Criteria Mining." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/17283014763907672061.
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碩士國立臺灣科技大學
資訊工程系
103
In recent years, the rise of smartphones and digital cameras makes it easier to take photos and a mass amount of photos are spread on the Internet. Photographic aesthetics is some sort of art which is expressed by the professional photographers’ aesthetic sensibilities and emotion. Moreover, many professional photographers make adjustments to the photos in post, and let photos much become more beautiful and meet the conditions of photographic aesthetics rules. Enhancing the images followed by ambiguous photographic aesthetics become a big task for computer. In this thesis, an automatically image enhancement based on the aesthetics images dataset from the internet is proposed. We used many method to analyze an image such as RMS method, Laplace of Gaussian method, saliency map method, Gabor filter method and so on. We can use above sixteen features extracted from image to judge an image is good or not. We present a new concept to enhance images by using cluster styles which are generated from X-means and CART decision tree. When an input image is judged as a bad image by CART decision tree, the reason can be traced back by the decision tree characteristic to know which features needs enhancement. We list ten features which can enhance image efficiently such as gamma correction, Gaussian blur and so on. We use Interval Halving method to approach the value which come from giving suggestion of a feature by CART decision tree based on contemporary aesthetics criteria. In the experiments, we apply cluster and classification to our dataset, and the average of cluster’s accuracy is 96.8%. In the enhancement part, we use CART decision tree aesthetic suggestion which means some feature are not enough or some feature are too high that can enhance our image step by step. Then we can get differently image style result like professional photographers do.
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Wu, Jeng-horng, and 吳振宏. "The Comparative Study about the Effects of Using Online Teacher Assessment Mechanism and Peer Assessment Mechanism on College Students’ Performance of Photography Course." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/72523805288828116938.
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碩士國立臺南大學
教育學系科技發展與傳播碩士班
99
The aims of this study were to explore the difference in college students accepting different online assessment mechanisms between overall performance of photography course and five performance dimensions of photography course, and to understand college student''s learning reflection on peer assessment in photography course. The subjects of this study were two college classes, a class of students went through online teacher assessment mechanism, and another class of students went through online peer assessment mechanism. Two classes of students involved in a quasi-experimental design with pretest, posttest and delayed posttest to evaluate their performance of photography course. After eight weeks, one class going through online peer assessment mechanism were selected to survey their performance satisfaction of photography course. The main conclusions of this study were as follows: 1. In terms of the immediate effects and delay effects of using online teacher assessment mechanism and peer assessment mechanism on college students’ overall performance of photography courses, there was no significant difference between two assessment mechanisms. 2. In terms of the immediate effects and delay effects of using online teacher assessment mechanism and peer assessment mechanism on college students’ five performance dimensions of photography course, there was no significant difference between two assessment mechanisms. 3. The learning reflection of 80% students in online peer assessment mechanism group reached high-level. 4. The students in peer assessment mechanism group expressed high performance satisfaction on overall performance of photography courses.
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Jukes, Vanessa. "Myth and mechanism: exhibiting the unexpected Saskatchewan landscape." 2012. http://hdl.handle.net/1993/8479.
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Through inquiry, experience, and discovery, this practicum reveals the landscape of Old Wives Lake, Saskatchewan and the prairie pothole region that surrounds it. It is my intention for this work to become a device for the revealing of unseen forces, for the creation of a different attention, an altering of perception, and an openness to a unique landscape of ever changing and shifting phenomena. It is accepted that complex systems, cannot be fully understood without time, patience, and commitment; however, through learning, understanding and revealing, the potential to not simply ‘see’ a landscape, but ‘read’ a landscape is harvested to enlighten and share in its discovery. The result is an exhibition of the unexpected Saskatchewan landscape.
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Lin, Xiang. "Direct coupling of imaging to morphology-based numerical modeling as a tool for mechanics analysis of wood plastic composites." Thesis, 2011. http://hdl.handle.net/1957/26472.
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Polymeric composites reinforced with bio-materials have advantages over composites with synthetic reinforcements. Bio-based composites use low-cost and renewable reinforcements, have nonabrasive properties for machining, have improved damping characteristics, and have potential for energy recycling. However, the limited use of bio-based composites is because their mechanical properties are typically much lower than those of synthetic composites.
The objective of this study was to combine state-of-the-art imaging tools with emerging numerical modeling methods for an integrated, multi-level characterization of bio-based reinforcements and their composites. Digital photography (2D) will allow collection of full-field digital images of the surface of sample composites, which will be used for characterization of the morphological structure of fillers (copper wire or wood particle) and of model composites. Mechanical experiments (tension load) on isolated fillers and on model composites will allow imaging of the deformed material. By correlating relative positions of thousands of surface features between consecutive images, digital image correlation (DIC) algorithms can be used to map surface deformation fields and calculate surface strain fields.
Digital imaging methods can only record deformations and strains. The interpretation of those strains in terms of material properties, such as position-dependent modulus of a heterogeneous composite material, requires simultaneous modeling. The modeling must
use morphology-based methods that can handle anisotropy, heterogeneity, and the complex structure of bio-based composites such as wood plastic composites. This research used the material point method (MPM) as a modeling tool. MPM is a particle-based, meshless method for solving problems in computational mechanics. The crucial advantage of MPM over other methods is the relative ease of translating pixels from digital images into material points in the analysis. Thus digital images (2D) used in our experiments were used as direct input to the MPM software, so that the actual morphologies, rather than idealized geometries, were modeled. This procedure removes typical uncertainties connected with idealization of the internal features of modeled materials. It also removes variability of specimen to specimen due to morphology variations.
Full-field imaging techniques and computer modeling methods for analysis of complex materials have developed independently. This research Coupled imaging and modeling and used inverse problem methodology for studying bio-particulate composites. The potential of coupling experiments with morphology-based modeling is a relatively new area. This work studied the morphology and mechanical properties of copper wire (for validation experiments) and wood particles used for reinforcement in polymer composites. The goal was to determine the in situ mechanical and interfacial properties of copper wire and then wood particles. By comparison of DIC results to MPM, the conclusion is MPM simulation works well by simulating 3D composite structure and using Matlab software to do qualitative and quantitative comparisons. Copper validation tests showed that copper wire is too stiff compared to polymer such that the inclusion modulus had low effect on the surface strains (DIC experimental results). Wood particle worked better because modulus of wood is much lower than copper. By qualitative comparison of the wood particle specimens, we could deduce that the in situ properties of wood particles are lower than bulk wood. Quantitative analysis concentrated on small area and got more exact results. In a 90 degree particle quantitative study, MPM simulations were shown to be capable of tracking the structure of wood particle plastic, which involved failure. The entire approach, however, is not very robust. We can get some results for mechanical properties, but it does not seem possible to extract all anisotropic properties from a few DIC tests, as some researcher have suggested.Graduation date: 2012
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Hsu, Cheng-Hsing, and 許正興. "Ⅰ.An effective one-trap-level TCAD model for proton-induced semi-insulating substrates rendered by the general SOC integration platform: Particle-Beam Stand (PBS)Ⅱ.A preliminary research on the possible physical mechanism of the Kirlian Photography." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/tg4ng5.
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碩士國立虎尾科技大學
光電與材料科技研究所
93
Ⅰ.A π technology (PEI = particle-enhanced isolation) had previously been proposed to employ energetic proton beams on the already-manufactured mixed-mode (analog-digital) IC wafers (prior to packaging) for the suppression of undesirable substrate coupling. Results of an improvement of 25-30 dB in noise coupling reduction and a great enhancement of 100-300 % on Q values of on-chip inductors had also been reported. Today, continued evaluations of this π technology have persuaded some chipmakers into realizing a new VLSI back-end facility: the particle-beam stand (PBS), which may ultimately become the general SOC (system-on-a-chip) integration platform. However, up to this day the physics behind such proton-caused defect phase has not been properly addressed. Thus, in this work, an effective 1-level defect model is constructed by fitting the existing single-trap-level theory with experimentally obtained parameters and those from numerical simulations of the SRIM (The Stopping and Range of Ions in Matter) (or previously, TRIM -- the Transport of Ions in Matter) code, a charged-particle stopping-power calculation program. It is realized that, more than being simple traps of charge carriers, these proton-created defects are also intrinsically charged (carrying +e or -e) and thus all are contributing to the Rutherford-like scattering of the then remaining free charge carriers. The calculated effective single trap level (ET) is shown to be about +0.24 eV in n-Si and -0.34 eV in p-Si, measuring from center of the energy band-gap. Ⅱ.In the early days of the 20th century, Russian scientist Kirlian and his wife discovered a new kind of photography, commonly known as the Kirlian Photography. By displaying bright halo or glow around objects taken, it further claimed to be capable of revealing the energy patterns emitted by human bodies for medical and psychological purposes. For Kirlian photography, maybe the most amazing demonstration by far is known as the “phantom-leaf” experiment. Namely, a leaf with portions of it cut off appeared in the photography as a whole leaf intact. Up to this day, however, the mechanism(s) behind Kirlian photography has never been certain. Some claimed that due to the constant release of various types of molecules from human body, the high-voltage, high-frequency electric field used in the Kirlian exposure accelerated and ionized these molecules to generate radiations which in turn contributed to the observed halo. Others argued instead that the Kirlian phenomena were the mere result of interactions between the applied AC electric field and bio-plasma (or bio-energy field) of human body. Other than the above two opposing conjectures, it was noticed that nonliving objects, such as a key or coin, also gave out Kirlian halos, and so far no satisfactory explanation has been given for that. On the application front, however, researches conducted over the last several decades worldwide, unfortunately, have only led to more divided opinions over the role played by the Kirlian photography. Some have allegedly confirmed beyond doubt that Kirlian photography has recorded the bio-energy distribution around human body and provided a very comprehensive image of the functioning of the entire mind-body system. In fact, there are already many applications of it, including: measuring the life-force in seeds and plants, detecting illness before physical symptoms appear, investigating residual toxic effects of drug addiction, assessing psychological compatibility between two people, evaluating the ability of a therapist to activate the self-healing processes in a patient, and for use in conjunction with other therapies such as acupuncture, homoeopathy and spiritual healing, as a cross check to the effectiveness of the methods, to name just a few, even though its physical mechanism was never made clear. On the other side, there are strong opinions claiming that the whole Kirlian phenomena could just be a manifestation of the unstable air or water vapor corona discharge, in addition to the fact that the results are simply not repeatable. Under such circumstances, this thesis work aimed to conduct several preliminary experiments concerning scientific inspection into the frequency aspects of the Kirlian phenomena, disregarding its functions, effectiveness as well as aesthetics.