Azopolymers represent a wide class of polymeric systems in which the azobenzene chromophores are either incorporated into the main chain or covalently attached to it as a part of side chain. Light with an appropriate wavelength induces cyclic trans-cis isomerization, which results in preferred orientation of the trans-isomers perpendicular to the light polarization. Most azopolymer materials directionally deform in the presence of various light polarizations. In this thesis, a study is presented for photoinduced deformations in glassy side-chain azopolymers under different irradiation patterns. In particular, the photodeformations are investigated under homogeneous irradiation with linearly and circularly polarized light, and under inhomogeneous irradiation with intensity and polarization interference patterns. It is proposed to explain these mechanical deformations using the orientation approach, which takes into account the reorientation of the chromophores. Due to the rigid attachment of the chromophores with the main chain, the backbone segments in side-chain azopolymers should reorient into the polarization plane, which is accompanied by appearance of light induced stress. To describe the time evolution of light induced stresses, the side-chain azopolymers are modeled as an ensemble of rigid segments in presence of the effective orientation potential. Implementing the stress in a viscoplastic material model of the finite element software ANSYS, it is shown that a square azopolymer post elongates along the polarization for the linearly polarized light and contracts along the propagation direction for the circularly polarized light. Also, the deformations in the elongated oriented colloids under intensity interference patterns are modeled and it is found that the formation of beads and wave-like structures are in accordance with the experiment. The orientation approach also reproduces the peculiar structures at the edges of thin azopolymer film under polarization interference patterns. Hence, the orientation approach correctly predicts local variations of the light induced stress in each illumination pattern for both initially isotropic and highly oriented materials. With this, it is proved that the orientation approach implements a self-sufficient and convincing mechanism to describe photoinduced deformation in azopolymer materials, which does not rely on the photo-fluidization concept. The viscoplastic material modeling, developed in this thesis, can be used to describe the inscription of intricate surface structures under complex interference patterns.

Esta dissertação foca um processo de criação de imagens fotográficas a partir de manipulações químicas feitas sobre superfícies fotossensíveis, diretamente sobre o papel ou negativo, sem utilizar para isso o aparato tecnológico – a câmera. A partir dessa abordagem, a dissertação analisa os limites daquilo que conhecemos como fotografia. A pesquisa convergiu para a investigação das possibilidades fotográficas inerentes às superfícies sensíveis e fotossensíveis, às soluções fotoquímicas e para o cruzamento dessas possibilidades fotográficas com outras linguagens artísticas. O trabalho confrontou a fotografia com suas especificidades e buscou desvendar os domínios da fotograficidade, que se configurou como um lugar apropriado para vasculhar as certezas e incertezas do que é a fotografia. As reflexões teóricas foram instituídas pelo trabalho plástico. / This dissertation aims at a photographic images creation process from chemistry manipulations made over light sensitive surfaces, directly on the paper or negative, without the camera. From this point of view the dissertation analyses the limits of which we know as photograph. The research converged to an investigation of the inherent photographic possibilities to sensitive and light sensitive surfaces, to photochemical solutions and to an approaching of these photographic possibilities to other kinds of artistic languages. The creation process faced photograph and its unique features and, by dealing with them, tried to reveal the photographs unique characteristics, which showed a specific place to search the certainties and uncertainties of what photography is. The theoretic reflections were established by the artistic work.

Esta dissertação foca um processo de criação de imagens fotográficas a partir de manipulações químicas feitas sobre superfícies fotossensíveis, diretamente sobre o papel ou negativo, sem utilizar para isso o aparato tecnológico – a câmera. A partir dessa abordagem, a dissertação analisa os limites daquilo que conhecemos como fotografia. A pesquisa convergiu para a investigação das possibilidades fotográficas inerentes às superfícies sensíveis e fotossensíveis, às soluções fotoquímicas e para o cruzamento dessas possibilidades fotográficas com outras linguagens artísticas. O trabalho confrontou a fotografia com suas especificidades e buscou desvendar os domínios da fotograficidade, que se configurou como um lugar apropriado para vasculhar as certezas e incertezas do que é a fotografia. As reflexões teóricas foram instituídas pelo trabalho plástico. / This dissertation aims at a photographic images creation process from chemistry manipulations made over light sensitive surfaces, directly on the paper or negative, without the camera. From this point of view the dissertation analyses the limits of which we know as photograph. The research converged to an investigation of the inherent photographic possibilities to sensitive and light sensitive surfaces, to photochemical solutions and to an approaching of these photographic possibilities to other kinds of artistic languages. The creation process faced photograph and its unique features and, by dealing with them, tried to reveal the photographs unique characteristics, which showed a specific place to search the certainties and uncertainties of what photography is. The theoretic reflections were established by the artistic work.

Esta dissertação foca um processo de criação de imagens fotográficas a partir de manipulações químicas feitas sobre superfícies fotossensíveis, diretamente sobre o papel ou negativo, sem utilizar para isso o aparato tecnológico – a câmera. A partir dessa abordagem, a dissertação analisa os limites daquilo que conhecemos como fotografia. A pesquisa convergiu para a investigação das possibilidades fotográficas inerentes às superfícies sensíveis e fotossensíveis, às soluções fotoquímicas e para o cruzamento dessas possibilidades fotográficas com outras linguagens artísticas. O trabalho confrontou a fotografia com suas especificidades e buscou desvendar os domínios da fotograficidade, que se configurou como um lugar apropriado para vasculhar as certezas e incertezas do que é a fotografia. As reflexões teóricas foram instituídas pelo trabalho plástico. / This dissertation aims at a photographic images creation process from chemistry manipulations made over light sensitive surfaces, directly on the paper or negative, without the camera. From this point of view the dissertation analyses the limits of which we know as photograph. The research converged to an investigation of the inherent photographic possibilities to sensitive and light sensitive surfaces, to photochemical solutions and to an approaching of these photographic possibilities to other kinds of artistic languages. The creation process faced photograph and its unique features and, by dealing with them, tried to reveal the photographs unique characteristics, which showed a specific place to search the certainties and uncertainties of what photography is. The theoretic reflections were established by the artistic work.

No description available.

Beaucoup d’applications en ingénierie demandent l’utilisation de matériaux intelligents qui peuvent se déformer en réponse à un stimulus extérieur. C’est dans ce contexte, que s’est posé ce projet de recherche. Bénéficiant d’un environnement pluridisciplinaire, grâce à l’association de deux axes de l'Institut Pascal : l’axe MMS (Mécanique, Matériaux et Structures) et l’axe PHOTON (Axe Photonique, Ondes, Nanomatériaux), cette thèse s’intègre parfaitement dans l’action transversale "Matériaux et Modélisations multi-échelles" du laboratoire. La première partie de ce travail s'appuie sur un système expérimental mis au point par une équipe américaine [Chang_10] qui permet la mesure sans contact du pH d'une solution en exploitant les caractéristiques photoniques du système. Ce système est composé d'un réseau d'hydrogel fixé sur un substrat rigide. Un modèle numérique est développé dans le but de simuler le fonctionnement de l'ensemble et d'optimiser le réseau d'hydrogel en vue d'applications dans le domaine médical. La seconde partie de ce travail concerne le développement d'une théorie sur le comportement mécanique de polymères sensibles à la lumière. L'objectif est d'établir une relation liant la déformation du matériau à l’intensité lumineuse. Les résultats obtenus sont comparés avec les résultats expérimentaux issus de la littérature. L'influence des interactions entre les molécules d'azobenzènes sur la déformation du matériau est étudiée. / Many engineering applications involve stimuli-responsive materials that can change their shape under the action of an external stimulus. It is in this context that this project takes place. Thanks to a multidisciplinary environment with the association of two lines of research of the Institut Pascal: the Mechanical area (Mechanic, Materials and structure) and the Photonic area (Nanostructures and Nanophotonics), this PhD perfectly fits with the “Materials and multi-scale Modeling” transversal action of the laboratory. The first part of this work relies on an experimental system developed by an American team [Chang_10] which allows to measure the pH of a solution without contact, making use of its photonic characteristics. This system is composed of a hydrogel network fixed on a rigid substract. A numerical model is developed in order to simulate its behavior and optimize the hydrogel network with a view to applications in the medical domain. The second part of this PhD is related to the development of a theory on the mechanical behavior of photo-sensitive polymers. The aim is to establish a link between the material deformation and the light intensity. The obtained results are compared to experimental ones from literature. The interaction influence of the azobenzenes molecules on the material strain is studied.

Les protéines fluorescentes photocommutables (RSFPs) ont la propriété de passer d’un état fluorescent à un état non-fluorescent en réponse à la lumière. Cette propriété en fait des outils de marquage pour la microscopie de super-résolution (ou nanoscopie). Le mécanisme de photocommutation implique l’isomérisation du chromophore ainsi qu’un changement d’état de protonation de ce dernier. Le mécanisme a été très étudié par différentes approches de spectroscopie et de simulation mais reste encore mal compris, l’ordre séquentiel des évènements est notamment encore débattu. Certains de ces évènements de la photocommutation se déroulent à des échelles de temps très courtes, ce qui rend difficile l’étude structurale par cristallographie des rayons X à l’aide des sources synchrotron actuelles dont la résolution temporelle est encore limitée. Les lasers à électrons libres (XFELs) sont une nouvelle source de rayons X produisant des impulsions suffisamment courtes pour permettre l’étude structurale des intermédiaires précoces ou à courte durée de vie qui se forment ou cours de la photocommutation, et suffisamment brillantes pour permettre la collecte de données cristallographiques sur des cristaux de tailles nano- et micrométrique. L’utilisation de ce nouveau genre d’instrument a permis l’émergence de la cristallographie sérielle, une nouvelle approche de la cristallographie des rayons X. Cette approche a depuis été adaptée aux lignes synchrotrons.Le travail présenté ici se focalise sur l’étude de rsEGFP2, une protéine fluorescente photocommutable de la famille de la GFP. Il y est décrit la mise au point d’un protocole de microcristallisation permettant l’obtention d’échantillons en vue d’une expérience de cristallographie résolue en temps au XFEL. Un mécanisme de photocommutation y est proposé à travers le résultat de deux expériences sur les deux XFELs actuellement opérationnels, à des échelles de temps différentes, dévoilant un chromophore « twisté » à l’état excité ainsi qu’un état cis protoné de ce dernier. La caractérisation structurale des variants de rsEGFP2 par cristallographie d’oscillation « classique » combinée à la découverte fortuite d’une conformation alternée du chromophore dans l’état non-fluorescent, issue d’expérience de cristallographie sérielle, apporte un complément d’explication des propriétés photophysiques de la protéine. / Reversibly switchable fluorescent proteins (RSFPs) are able to reversibly toggle between a fluorescent on-state and a non-fluorescent off-state under visible light irradiation. This property makes them a suitable marker used in super-resolution microscopy (or nanoscopy). The photo-switching mechanism involves isomerisation of the chromophore and a change of its protonation state. This mechanism has been well studied but remains poorly understood. The structural nature and the sequential order of atomistic events are still under debate. Some of them take place on the ultra-fast time scale and make structural investigation by X-ray crystallography impossible using current synchrotron radiation sources whose temporal resolution they offer is limited. X-ray free electron lasers (XFELs) are a new kind of X-ray source producing femtosecond pulses that allow structural investigation of ultra-fast intermediates during photoswitching. They are also so bright that crystallographic data collection from micro- and nanometer-sized crystals became possible. The bright and short XFEL pulses required a new methodology to be developed, the so-called serial crystallography methodology. This method is now being adapted to synchrotron radiation facilities.Here is presented a time-resolved crystallography study of the reversibly switchable green fluorescent protein 2 (rsEGFP2). A microcrystallization protocol is described allowing the preparation of suitable samples in large amounts for time-resolved serial crystallography experiments. A photoswitching mechanism of rsEGFP2 is proposed based on crystallographic results obtained from data collected at the two XFEL facilities currently fully operational, i.e. the LCLS in the USA and SACLA in Japan. In particular, the structure of two photoswitching intermediates have been determined, one featuring a twisted chromophore in the excited state and the other displaying a protonated cis isomer of the chromophore in the ground state. The structural characterization of rsEGFP2 variants by traditional oscillation crystallography combined with the serendipitous discovery of an alternate chromophore conformation in the off-state during an XFEL experiment provided unique insight into the photophysical behavior of the protein.

Denna studie är ett examensarbete som utförs som en del av utbildningen Produktutveckling med inriktning ljusdesign under våren 2018 vid Jönköpings Tekniska Högskola. Studien gjordes för att undersöka hur belysning kan underlätta orientering i mörka utställningsrum, utan att negativt påverka den upplevda atmosfären samtidigt som utställningsföremålen är i fokus för besökarna. Målet är att kunskapen som samlas in från denna studie ska kunna användas för att skapa ett underlag vid planering av belysning på Marinmuseet i Karlskrona. Studien genomfördes först genom en förstudie där problem och förutsättningar för att orientera sig i mörka utställningsrum undersöktes genom en enkät och en observationsstudie på Vasamuseet och Marinmuseet. En huvudstudie genomfördes sedan på Marinmuseet där. Lou Michels teori Visual Objective Theory prövades som ett verktyg för att underlätta orientering i mörka utställningsrum. Huvudstudien genomfördes under två dagar med hjälp av en enkätundersökning och en observationsstudie. Resultatet från enkätstudien antydde att upplevelsen av atmosfär kan påverkas av Visual Objective Theory, dock finns det inget som pekar mot att den påverkas negativt. I övrigt gav enkätstudien inga starka implikationer till en slutsats. Observationsstudien var mer tydlig och gav underlag för att Visual Objective Theory är ett bra verktyg för att påverka besökarnas rörelsemönster. / This study is a thesis performed as a part of the education Product development aligned with Lighting design during the spring 2018 at Jönköping School of Engineering. This study was made to research how lighting can facilitate orientation in dark exhibition rooms, without negatively affecting the experienced atmosphere while at the same time maintaining the exhibition subjects in focus for the visitors. The goal is that the knowledge collected from this study can be used as a basis when planning lighting at the Marine Museum in Karlskrona. The study was first performed through a prestudy where problems and conditions for orienting in dark exhibition rooms was tested with a survey and an observational study at the Vasamuseet and Marinmuseet. A main study was then performed at Marinmuseet, where Lou Michels theory Visual Objective Theory was tested as a tool to facilitate orientation in dark exhibition rooms. The main study was performed during two days, containing a questionnaire and an observational study. The results from the survey implied that the experience of atmosphere can be affected by Visual Objective Theory, however there is nothing implying that the experience is negatively affected. Other than that the results from the survey gave no strong implications for a conclusion. The observational study was clearer and gave support for Visual Objective Theory being a good tool for affecting the visitors movement patterns.

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.

A novel laser light-sensitive yarn based on a thermoplastic polyester–urethane (TPU) has been prepared and analyzed. Since the thermosensitive shape memory polymer yarn (SMP yarn) has been functionalized using nanoscale heat sources exhibiting light-induced heat generation, the yarn is capable of an optically triggered shape memory effect (SME). For this purpose gold nanorods (GNR) have been employed. In addition to the incorporation of GNR into the yarn, a coating of GNR on the yarn is also proposed, applied by a semi-continuous layer-by-layer (LBL) technique. The SME of the functionalized yarns can be triggered either thermally or optically and has a strain recovery of almost 100%. The light-induced SME is triggered by a low-powered laser (808 nm, 2 W for a GNR-incorporated and 1W for a GNRcoated TPU yarn). A reference yarn without GNR showed no significant effect. An adaptive structure featuring a SMPyarn backed shape memory effect has been proposed and demonstrated.