Dynamic control of laser driven proton beams by exploiting self-generated, ultrashort electromagnetic pulses

As part of the ultrafast charge dynamics initiated by high intensity laser irradiations of solid targets,high amplitude EM pulses propagate away from the interaction point and are transported along anystalks and wires attached to the target. The propagation of these high amplitude pulses along a thinwire connected to a laser irradiated target was diagnosed via the proton radiography technique,measuring a pulse duration of 20 ps and a pulse velocity close to the speed of light. The strongelectric field associated with the EM pulse can be exploited for controlling dynamically the protonbeams produced from a laser-driven source. Chromatic divergence control of broadband laser drivenprotons (upto 75% reduction in divergence of >5 MeV protons) was obtained by winding the supportingwire around the proton beam axis to create a helical coil structure. In addition to providingfocussing and energy selection, the technique has the potential to post-accelerate the transiting protonsby the longitudinal component of the curved electric field lines produced by the helical coil lens.

LOTUS: A low cost, ultraviolet spectrograph

We describe the design, construction and commissioning of LOTUS; a simple, low-cost long-slit spectrograph for the Liverpool Telescope. The design is optimized for near-UV and visible wavelengths and uses all transmitting optics. It exploits the instrument focal plane field curvature to partially correct axial chromatic aberration. A stepped slit provides narrow (2.5x95 arcsec) and wide (5x25 arcsec) options that are optimized for spectral resolution and flux calibration respectively. On sky testing shows a wavelength range of 3200-6300 Angstroms with a peak system throughput (including detector quantum efficiency) of 15 per cent and wavelength dependant spectral resolution of R=225-430. By repeated observations of the symbiotic emission line star AG Peg we demonstrate the wavelength stability of the system is less than 2 Angstroms rms and is limited by the positioning of the object in the slit. The spectrograph is now in routine operation monitoring the activity of comet 67P/Churyumov-Gerasimenko during its current post-perihelion apparition.

Clarinetas em Si Bemol e em Fá: diferenças acústicas e interpretativas

ALBERTO,Gabriel Gagliano Pinto. Clarinetas em Si Bemol e em Lá: diferenças acústicas e interpretativas. Belo Horizonte, MG, 2004. Orientador: Prof. Dr. Maurício Alves Loureiro. Dissertação (Mestrado) - Escola de Música da Universidade Federal de Minas Gerais.

Synthesis and characterization of eco-friendly inorganic yellow pigments for coloring applications

Research in the fields of ceramic pigments is oriented towards the enlargement of the chromatic set of colors together with a replacement for more expensive and less stable organic pigments. Novel non-toxic inorganic pigments have been required to answer environmental laws to remove elements like lead, chromium, cobalt entering in the composition of usual pigments widely used in paints and plastics. Yellow is particularly an important color in the pigment industry and consumption of yellow exceeds that of any other colored pigments. Apart from this, high infrared reflective pigments are now in great demand for usage in coatings, cement pavements, automotives and camouflage applications. They not only impart color to an object, but also reflect the invisible heat from the object to minimize heat build–up, when exposed to solar radiation. With this in view, the present work aims at developing new functional yellow pigments for these applications. A series of IR reflecting yellow pigments have been synthesized and analyzed for their crystalline structure, morphological, composition and optical characteristics, coloring and energy saving applications

Hur grafiska formgivare runt om i världen uppfattar skandinavisk grafisk design

Syftet med föreliggande studie har varit att kartlägga hur grafiska formgivare runt om i världen uppfattar skandinavisk grafisk design. 53 deltagare från industriländer deltog i studien som använde en kombination av mail-intervjuer och enkäter. Resultaten från denna studie indikerar att, oavsett kontinent, upplevs skandinavisk grafisk design som enkel och funktionell. Layouten uppfattades som rutnätsbaserad med mycket ljusrum och få grafiska element. Monokroma färger som svart, vit och grå utan gradienter och skuggor uppfattades som typiska för skandinavisk grafisk design; följt av jord- och pastellfärger. Sanserifer var mest förknippade med skandinavisk grafisk design. Motiv ansågs i denna studie att användas sparsamt, men när de används avbildar de naturen eller geometriska former. Foton och illustrationer ansågs användas ungefär lika mycket, illustrationer hade en smärre större preferens. Den upplevda påverkan av skandinavisk grafisk design varierade mellan deltagarna. Deltagarna som tyckte att påverkan var stor, ansåg att detta berodde på förespråkandet av enkelhet och funktion, sammanflätning av designområden och/eller frammaning av hållbar grafisk design. Deltagarna som ansåg att påverkan var låg, tyckte att för lite publicitet var en bidragande faktor.De flesta deltagarna i denna undersökning ansåg att skandinavisk grafisk design var enklare i jämförelse med vad de kunde se i sina hemländer. Vidare tyckte afrikanska, asiatiska och sydamerikanska deltagare  att färgerna hade lägre kroma.

Quantitative evaluation of visual function 12 months after bilateral implantation of a diffractive trifocal IOL

PURPOSE: To quantitatively evaluate visual function 12 months after bilateral implantation of the Physiol FineVision® trifocal intraocular lens (IOL) and to compare these results with those obtained in the first postoperative month. METHODS: In this prospective case series, 20 eyes of 10 consecutive patients were included. Monocular and binocular, uncorrected and corrected visual acuities (distance, near, and intermediate) were measured. Metrovision® was used to test contrast sensitivity under static and dynamic conditions, both in photopic and low-mesopic settings. The same software was used for pupillometry and glare evaluation. Motion, achromatic, and chromatic contrast discrimination were tested using 2 innovative psychophysical tests. A complete ophthalmologic examination was performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Psychophysical tests were performed 1 month after surgery and repeated 12 months postoperatively. RESULTS: Final distance uncorrected visual acuity (VA) was 0.00 ± 0.08 and distance corrected VA was 0.00 ± 0.05 logMAR. Distance corrected near VA was 0.00 ± 0.09 and distance corrected intermediate VA was 0.00 ± 0.06 logMAR. Glare testing, pupillometry, contrast sensitivity, motion, and chromatic and achromatic contrast discrimination did not differ significantly between the first and last visit (p>0.05) or when compared to an age-matched control group (p>0.05). CONCLUSIONS: The Physiol FineVision® trifocal IOL provided satisfactory full range of vision and quality of vision parameters 12 months after surgery. Visual acuity and psychophysical tests did not vary significantly between the first and last visit.

Développement de fibres optiques composites pour la génération du supercontinuum dans l’infrarouge

Les sources laser à large bande possédant les caractéristiques requises pour émettre sur la plage spectrale correspondant à la seconde fenêtre de transmission atmosphérique (3 à 5 μm) exercent un attrait considérable pour divers domaines tels que la télédétection de polluants atmosphériques et les contremesures infrarouges. Les supercontinua générés à l’intérieur de fibres optiques représentent une option intéressante pour réaliser ce type de sources laser. En effet, ils possèdent une intensité élevée, un large contenu spectral, une excellente directionnalité de faisceau, ainsi qu’un bon potentiel pour constituer des sources lumineuses compactes et robustes. Toutefois, la génération d’un tel supercontinuum implique certains défis à relever sur le plan de la conception des fibres optiques employées. En fait, ces fibres optiques doivent présenter de faibles pertes de propagation sur la plage spectrale de 3 à 5 μm, posséder un paramètre de non-linéarité élevé et permettre le pompage en régime anomal de dispersion à des longueurs d’onde pour lesquelles des sources laser compactes sont offertes commercialement. En matière de robustesse, ces fibres doivent également démontrer de bonnes propriétés mécaniques ainsi qu’une stabilité chimique appropriée vis-à-vis de la corrosion causée par l’humidité. Dans le cadre de cette thèse, un nouveau type de fibres composites à saut d’indice fortement contrasté a été développé pour atteindre ces objectifs de génération de supercontinuum. Ce type de fibres combine respectivement un verre de tellurite et un verre de germanate pour son coeur et sa gaine permettant ainsi d’atteindre une différence d’indice de réfraction d’environ 0.3 entre ces deux dernières structures. Grâce à cet important saut d’indice, ces fibres peuvent fortement confiner les modes optiques à l’intérieur de leur coeur, ce qui leur donne la possibilité d’atteindre un niveau élevé de non-linéarité et d’optimiser leurs caractéristiques de dispersion chromatique pour la génération du supercontinuum. D’autre part, leur section transversale toute solide leur confère aussi une meilleure stabilité environnementale comparativement à celle démontrée par les fibres optiques microstructurées à base de verres d’oxydes de métaux lourds, de verres de chalcogénure et de verres fluorés. Toutefois, leur fabrication nécessite l’appariement de verres dont les propriétés thermomécaniques concordent suffisamment ensemble pour permettre leur fibrage. Les travaux effectués ici démontrent la production de fibres optiques composites et leur potentiel pour la génération du supercontinuum dans l’infrarouge moyen.

Clarinetas em Si Bemol e em Fá: diferenças acústicas e interpretativas

ALBERTO,Gabriel Gagliano Pinto. Clarinetas em Si Bemol e em Lá: diferenças acústicas e interpretativas. Belo Horizonte, MG, 2004. Orientador: Prof. Dr. Maurício Alves Loureiro. Dissertação (Mestrado) - Escola de Música da Universidade Federal de Minas Gerais.

Teaching Sight-Reading to Undergraduate Choral Ensemble Singers: Lessons from Successful Learners

This study was designed to investigate professional choral singers’ training, perceptions on the importance of sight-reading skill in their work, and thoughts on effective pedagogy for teaching sight-reading to undergraduate choral ensemble singers. Participants in this study (N=48) included self-selected professional singers and choral conductors from the Summer 2015 Oregon Bach Festival’s Berwick Chorus and conducting Master Class. Data were gathered from questionnaire responses and audio recorded focus group sessions. Focus group data showed that the majority of participants developed proficiency in their sight-reading skills from instrumental study, aural skills classes, and through on-the-job training at a church job or other professional choral singing employment. While participants brought up a number of important job skills, sightreading was listed as perhaps the single most important skill that a professional choral singer could develop. When reading music during the rehearsal process, the data revealed two main strategies that professional singers used to interpret the pitches in their musical line: an intervallic approach and a harmonic approach. Participants marked their scores systematically to identify problem spots and leave reminders to aid with future readings, such as marking intervals, solfege syllables, or rhythmic counts. Participants reported using a variety of skills other than score marking to try to accurately find their pitches, such as looking at other vocal or instrumental lines, looking ahead, and using knowledge about a musical style or time period to make more intuitive “guesses” when sight-reading. Participants described using additional approaches when sight-reading in an audition situation, including scanning for anchors or anomalies and positive self-talk. Singers learned these sight-reading techniques from a variety of sources. Participants had many different ideas about how best to teach sight-reading in the undergraduate choral ensemble rehearsal. The top response was that sight-reading needed to be practiced consistently in order for students to improve. Other responses included developing personal accountability, empowering students, combining different teaching methods, and discussing real-life applications of becoming strong sight-readers. There was discussion about the ultimate purpose of choir at the university level and whether it is to teach musicianship skills or produce excellent performances.

Desenvolvimento e caracterização de sensores óticos de qualidade de líquidos

A necessidade de controlar de forma rápida, eficaz e precisa a qualidade de líquidos, principalmente a água, um bem essencial para os seres humanos, conduziu ao desenvolvimento de dispositivos capazes de relacionar a medição de parâmetros físicos com a qualidade da água. Estes dispositivos devem ser capazes de monitorizar os inúmeros parâmetros necessários para aferir a qualidade do líquido, como a turvação, índice de refração, concentração de sedimentos e propriedades cromáticas. Desta forma devem-se recorrer a sensores multiparâmetros. A tecnologia baseada em POF (fibra ótica polimérica) tem sido apontada com elevado potencial no desenvolvimento de sensores óticos nas mais variadas aplicações dado o seu baixo custo, imunidade a interferências eletromagnéticas e flexibilidade. Neste trabalho é proposto um sensor POF multiparâmetro capaz de reunir num único dispositivo a capacidade de medição de altos e baixos valores de turvação, assim como ter a capacidade de medir vários parâmetros em simultâneo e em tempo real. Os resultados permitem avaliar o aumento da capacidade de gama dinâmica de turvação e concentração de sedimentos face aos sensores multiparâmetros já comercializados, uma vez que houve uma boa resposta por parte do sensor para altos e para baixos valores. Um método utilizado para descorrelacionar os diferentes parâmetros foi aplicado com sucesso. A WATGRID LDA. pretende, partindo deste tipo de sensores, disponibilizar aos seus clientes soluções (plataformas) inteligentes e integradas para avaliação e gestão da qualidade dos líquidos para consumo (e.g. água e vinho). Estas soluções irão permitir que os clientes da WATGRID LDA. aumentem a sua eficiência, a qualidade do seu produto e tenham um maior controlo do processo ao mesmo tempo que reduzem custos.

Quantitative evaluation of visual function 12 months after bilateral implantation of a diffractive trifocal IOL

PURPOSE: To quantitatively evaluate visual function 12 months after bilateral implantation of the Physiol FineVision® trifocal intraocular lens (IOL) and to compare these results with those obtained in the first postoperative month. METHODS: In this prospective case series, 20 eyes of 10 consecutive patients were included. Monocular and binocular, uncorrected and corrected visual acuities (distance, near, and intermediate) were measured. Metrovision® was used to test contrast sensitivity under static and dynamic conditions, both in photopic and low-mesopic settings. The same software was used for pupillometry and glare evaluation. Motion, achromatic, and chromatic contrast discrimination were tested using 2 innovative psychophysical tests. A complete ophthalmologic examination was performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Psychophysical tests were performed 1 month after surgery and repeated 12 months postoperatively. RESULTS: Final distance uncorrected visual acuity (VA) was 0.00 ± 0.08 and distance corrected VA was 0.00 ± 0.05 logMAR. Distance corrected near VA was 0.00 ± 0.09 and distance corrected intermediate VA was 0.00 ± 0.06 logMAR. Glare testing, pupillometry, contrast sensitivity, motion, and chromatic and achromatic contrast discrimination did not differ significantly between the first and last visit (p>0.05) or when compared to an age-matched control group (p>0.05). CONCLUSIONS: The Physiol FineVision® trifocal IOL provided satisfactory full range of vision and quality of vision parameters 12 months after surgery. Visual acuity and psychophysical tests did not vary significantly between the first and last visit.

Emociones cromáticas: análisis de la percepción de color basado en emociones y su relación con el consumo de moda

La globalización del mercado actual exige que los productos sean novedosos, comerciales, funcionales y altamente llamativos, para despertar así en el consumidor la atención suficiente y lograr que se dé el momento de la compra, con la previa identificación de su necesidad y la aceptación del producto. Caracterizar al consumidor es complejo, y deben ser analizados diferentes aspectos como el color y las emociones. En este trabajo se estableció, la relación que existe entre la emoción, el color y el objeto moda, identificando las variables que motivan al consumidor en el momento de su compra. Para ello se aplicó una encuesta sobre una población universitaria en Colombia y, adicionalmente, mediante la base de datos DEAP perteneciente a 4 universidades de Europa (Queen Mary University de Londres, University of Twente de Holanda, University of Geneva y al EPFL de Suiza), que relaciona emociones y vídeos en una población universitaria de Europa, se hizo un análisis del color en la ambientación de estos y se demostró la influencia del color utilizando el gráfico de Geneve. Los resultados obtenidos demostraron una fuerte influencia del color en la actitud de consumo y del color sobre las emociones, aunque no se logró concluir que las emociones afecten el momento de adquisición por parte del consumidor.

Estudio de la pintura del paisaje campestre del Cantón Cuenca, siglo XX

La pintura de paisaje surge como corriente pictórica a finales del siglo XIX como un producto de una suma de intereses tanto académicos como científicos que desembocan en el interés por la naturaleza. Se enmarca dentro de un pensamiento político que sitúa a nuestro país en las expectativas de una nueva estructura socio cultural que pone énfasis en la libertad y en los derechos humanos, el derecho a la propiedad privada y sobre todo abre sus horizontes a la integración social y cultural, se ve la necesidad de comunicar e inspirarse en la propia tierra. En ésta investigación se pretende inquirir en los diferentes procesos que experimentan los artistas al contacto con la naturaleza; que se interiorizan a través de las distintas experiencias que tienen con las técnicas de proceso artístico, dentro de las cuales se capturan la luz, el espacio, la cromática, la vivencia que capta el espectador de las obras y las expectativas que tiene del artista. Este proceso puede o no ser artístico: algunas veces guiado por el academicismo, otras veces por encargo, con expectativas que muchas veces tienen fines políticos (poniendo en desmedro del valor académico, el tema). Obras que se traducen en una exigencia de la técnica, ya que se trata de captar la naturaleza, que de por sí es perfecta, en un prolijo uso casi perfeccionista de la misma, sin llegar a comprender que los individuos como las huellas dactilares, son diferentes en su interior; por lo que captarán la esencia de la naturaleza de acuerdo a las numerosas experiencias que hayan tenido con ella. La idea de pintar paisaje ya no está relacionada solamente con la observación sino con la perspectiva de representar el entorno de acuerdo a la manera muy particular y especial de cada artista.

Endoscopic optical coherence tomography : design and application

This thesis presents an investigation on endoscopic optical coherence tomography (OCT). As a noninvasive imaging modality, OCT emerges as an increasingly important diagnostic tool for many clinical applications. Despite of many of its merits, such as high resolution and depth resolvability, a major limitation is the relatively shallow penetration depth in tissue (about 2∼3 mm). This is mainly due to tissue scattering and absorption. To overcome this limitation, people have been developing many different endoscopic OCT systems. By utilizing a minimally invasive endoscope, the OCT probing beam can be brought to the close vicinity of the tissue of interest and bypass the scattering of intervening tissues so that it can collect the reflected light signal from desired depth and provide a clear image representing the physiological structure of the region, which can not be disclosed by traditional OCT. In this thesis, three endoscope designs have been studied. While they rely on vastly different principles, they all converge to solve this long-standing problem.

A hand-held endoscope with manual scanning is first explored. When a user is holding a hand- held endoscope to examine samples, the movement of the device provides a natural scanning. We proposed and implemented an optical tracking system to estimate and record the trajectory of the device. By registering the OCT axial scan with the spatial information obtained from the tracking system, one can use this system to simply ‘paint’ a desired volume and get any arbitrary scanning pattern by manually waving the endoscope over the region of interest. The accuracy of the tracking system was measured to be about 10 microns, which is comparable to the lateral resolution of most OCT system. Targeted phantom sample and biological samples were manually scanned and the reconstructed images verified the method.

Next, we investigated a mechanical way to steer the beam in an OCT endoscope, which is termed as Paired-angle-rotation scanning (PARS). This concept was proposed by my colleague and we further developed this technology by enhancing the longevity of the device, reducing the diameter of the probe, and shrinking down the form factor of the hand-piece. Several families of probes have been designed and fabricated with various optical performances. They have been applied to different applications, including the collector channel examination for glaucoma stent implantation, and vitreous remnant detection during live animal vitrectomy.

Lastly a novel non-moving scanning method has been devised. This approach is based on the EO effect of a KTN crystal. With Ohmic contact of the electrodes, the KTN crystal can exhibit a special mode of EO effect, termed as space-charge-controlled electro-optic effect, where the carrier electron will be injected into the material via the Ohmic contact. By applying a high voltage across the material, a linear phase profile can be built under this mode, which in turn deflects the light beam passing through. We constructed a relay telescope to adapt the KTN deflector into a bench top OCT scanning system. One of major technical challenges for this system is the strong chromatic dispersion of KTN crystal within the wavelength band of OCT system. We investigated its impact on the acquired OCT images and proposed a new approach to estimate and compensate the actual dispersion. Comparing with traditional methods, the new method is more computational efficient and accurate. Some biological samples were scanned by this KTN based system. The acquired images justified the feasibility of the usage of this system into a endoscopy setting. My research above all aims to provide solutions to implement an OCT endoscope. As technology evolves from manual, to mechanical, and to electrical approaches, different solutions are presented. Since all have their own advantages and disadvantages, one has to determine the actual requirements and select the best fit for a specific application.

Conservação e restauro de azulejo: metodologias de intervenção vs indicadores de compatibilidade

A escassez de parâmetros técnicos e científicos e o caráter subjetivo que em regra preside à escolha de determinado material, produto ou técnica suscitaram o interesse pelo presente tema onde se procurou aumentar as ferramentas de análise e de apoio à decisão em intervenções de conservação do património azulejar. Procurou compreender-se o azulejo a nível histórico, estético, técnico e material, estudando-o do ponto de vista físico, químico e mineralógico. Comparando o azulejo com as réplicas produzidas para intervenções de conservação e restauro estudadas, concluiu-se que as suas composições, química e mineralógica, são diferentes, embora não se verifiquem tantas dissemelhanças ao nível das propriedades físicas. As linhas orientadoras da conservação e restauro de azulejo foram lançadas por Santos Simões a partir dos anos 40 do séc. XX e, desde então, foi-se desenvolvendo um pouco à margem das restantes áreas de especialidade, mesmo ao nível do ensino. Os resultados do inquérito internacional junto dos profissionais que trabalham em conservação e restauro de azulejo in situ corroboram de certo modo este facto e, simultaneamente, permitem uma apreensão da situação atual. Constatou-se uma quase total ausência de documentação sobre intervenções realizadas, mas a análise de casos de estudo e de relatórios permitiu uma primeira sistematização da informação disponível segundo os materiais correntemente utilizados. Procedeu-se a uma identificação e tipificação de patologias decorrentes das intervenções procurando entender qual o papel que tiveram os materiais utilizados e as técnicas de intervenção no desempenho das intervenções. Os processos de reintegração volumétrica e cromática mereceram uma maior atenção, procedendo-se à simulação de todo o sistema, em contexto laboratorial, com base nos materiais correntemente utilizados. Os resultados revelam comportamento diferenciado dos materiais de origem orgânica e inorgânica, evidenciando estes últimos uma maior compatibilidade com o azulejo, mas um pior desempenho a médio/longo prazo. O reconhecimento das soluções mais ou menos compatíveis permitiu delinear uma metodologia de avaliação da compatibilidade, da eficácia e do desempenho dos materiais e das técnicas utilizadas, contribuindo também para a definição de algumas recomendações e de critérios de atuação; Abstract The lack of information found, when selecting a material, product or technique, to apply on a specific conservation treatment contributed to the interest on this topic. The historical, aesthetic and technical characteristics of the azulejo was researched by studying their physical, chemical and mineralogical properties. Comparing original azulejos with the replicas produced for conservation treatments studied, it was concluded that the chemical and mineralogical composition is different, although there are less dissimilarities in terms of physical properties. The guidelines for conservation and restoration were launched by Santos Simões in the 40s and since then, it has been developing a bit on the sidelines of the remaining areas of expertise, even at an educational level. The results of an international survey, near professionals working in conservation and restoration of azulejo in situ, corroborate this fact and simultaneously allow an insight of the current situation. It was found an almost complete lack of technical documentation about previous conservation interventions, but the analysis of existent case studies and intervention reports permitted a systematization of the available information, also considering the materials commonly used. The identification and characterization of damages resulting from interventions, was performed trying to establish a correlation with the materials used and intervention techniques. The attention focused on the study of the infills and chromatic reintegration and a simulation of the entire system was developed, in a laboratory context, on the basis of commonly used materials. The results reveal a distinct behavior between the organic and inorganic materials, showing the latter greater compatibility with the azulejos but a worse medium/long-term performance. The recognition of more or less compatible solutions allowed to outline a methodology to evaluate the compatibility, efficiency and performance of materials and techniques used, also contributing to define some recommendations and action criteria.