As part of the Bagnold Dune campaign conducted by Mars Science Laboratory rover Curiosity, visible/near-infrared reflectance spectra of dune sands were acquired using Mast Camera (Mastcam) multispectral imaging (445-1013nm) and Chemistry and Camera (ChemCam) passive point spectroscopy (400-840nm). By comparing spectra from pristine and rover-disturbed ripple crests and troughs within the dune field, and through analysis of sieved grain size fractions, constraints on mineral segregation from grain sorting could be determined. In general, the dune areas exhibited low relative reflectance, a weak similar to 530nm absorption band, an absorption band near 620nm, and a spectral downturn after similar to 685nm consistent with olivine-bearing sands. The finest grain size fractions occurred within ripple troughs and in the subsurface and typically exhibited the strongest similar to 530nm bands, highest relative reflectances, and weakest red/near-infrared ratios, consistent with a combination of crystalline and amorphous ferric materials. Coarser-grained samples were the darkest and bluest and exhibited weaker similar to 530nm bands, lower relative reflectances, and stronger downturns in the near-infrared, consistent with greater proportions of mafic minerals such as olivine and pyroxene. These grains were typically segregated along ripple crests and among the upper surfaces of grain flows in disturbed sands. Sieved dune sands exhibited progressive decreases in reflectance with increasing grain size, as observed in laboratory spectra of olivine size separates. The continuum of spectral features observed between the coarse- and fine-grained dune sands suggests that mafic grains, ferric materials, and air fall dust mix in variable proportions depending on aeolian activity and grain sorting.

Les littératures lesbiennes francophones montrent, d’une part, que les lesbiennes sont absentes du réel, car leur existence est réduite à l’(in)visibilité publique, sociale et historique, sur laquelle elles n’ont pas le contrôle et qui voile leur capacité à se réfléchir et s’inventer par et pour elles-mêmes. D’autre part, elles développent un système de reconnaissance politique en parallèle du modèle dominant. L’objectif de cette thèse est de montrer ce que permettent la littérature, et spécifiquement les littératures lesbiennes francophones, pour conjurer cette absence des lesbiennes. Il est question, plus particulièrement, de montrer que cette occultation est freinée par des pratiques du tiers espace. Il s’agit d’une notion qui émerge des études postcoloniales, géographiques et queer of color. Elle dénote une manière de reconfigurer deux éléments, lieux, ou perspectives en un troisième qui dépasse leur condition première d’existence afin de rendre le réel plus habitable. En tant qu’outil littéraire, nous avançons qu’il s’agit autant d’une manière de lire que d’écrire. Dans la première partie, nous étudierons les trois principales cultures du visible mises en scène dans notre corpus à travers une pratique de lecture du tiers espace, c’est-à-dire en tournant notre regard vers de nouveaux lieux d’autorité dans lesquels les personnages parviennent à définir leur identité au-delà de ces cultures. Dans la deuxième partie, nous nous attarderons sur le réalisme virtuel en tant que pratique d’écriture du tiers espace. Nous nous pencherons sur ses deux dimensions, documentaire et interactive, qui réinventent aussi bien le passé que la prise de parole. Notre recherche est aussi audacieuse : elle ose nommer un corpus, celui des littératures lesbiennes francophones, participant à combattre l’absence réelle des lesbiennes de l’espace public, social et historique.

Photocatalysis is a series of advanced light-induced redox reaction processes resulting in the degradation and mineralization of organic pollutants in the presence of oxygen and water. Due to their capability to destroy contaminants under mild conditions, photocatalytic processes have attracted considerable attention in the field of waste-water treatment. However, photocatalytic reactions using the traditional TiO2 photocatalyst suffer from low energy efficiencies under solar irradiation. This low efficiency in the utilization of solar energy lies in its incapability in absorbing visible lights and also the high recombination rate of photo-excited species in photocatalysts. In addition, difficulties in the separation of fluids from micro- or nano-scale catalysts in large scale systems substantially impact cost efficiency in practice. In this thesis, strategies are explored which address these issues in order to improve the feasibility of solar photocatalysis. Two branches of photocatalytic transition metal-oxide semiconductor materials are investigated, namely bismuth-based and silver-based multi-phase heterogeneous photocatalysts. This research is focused on the design of visible-light-active metal-oxide photocatalysts to increase the absorption of visible light and to decrease the rates of electron-hole recombination, resulting in a high photocatalytic efficiency in regards to the degradation of organic pollutants. BiVO4 powder, synthesized from freshly made potassium metavanadate was prepared via hydrothermal treatment, characterized and experimentally investigated for the degradation of rhodamine B under visible light irradiation. The crystal structures and the specific surface areas of the composites, based on BiVO4 single phase crystal structures, are discussed. A multi-phase silver species (Ag2O/Ag3VO4/Ag4V2O7) photocatalyst was synthesized by adjusting the molar ratio of silver to vanadium (Ag to V) via hydrothermal method. The stabilities of as-prepared silver species composites regarding crystal structural changes due to photocatalytic reactions are investigated. Multi-phase silver species composites assisted with graphene oxide (GO-Ag2O/Ag3VO4/AgVO3) were synthesized at room temperature, and exhibited high visible-light photocatalytic activities regarding the degradation of model organic pollutants. The effect of graphene oxide addition on the photoactivity and on the photocorrosion of silver species composites under VLI is explored. The synergistic roles of each individual phase incorporated into the multi-phase composites are discussed regarding the photocatalytic performance.

We review astronomical results in the visible (lambda<1 mu m) with adaptive optics. Other than a brief period in the early 1990s, there has been little (<1 paper/yr) night-time astronomical science published with AO in the visible from 2000-2013 (outside of the solar or Space Surveillance Astronomy communities where visible AO is the norm, but not the topic of this invited review). However, since mid-2013 there has been a rapid increase visible AO with over 50 refereed science papers published in just similar to 2.5 years (visible AO is experiencing a rapid growth rate very similar to that of NIR AO science from 1997-2000; Close 2000). Currently the most productive small (D < 2 m) visible light AO telescope is the UV-LGS Robo-AO system (Baranec, et al. 2016) on the robotic Palomar D=1.5 m telescope (currently relocated to the Kitt Peak 1.8m; Salama et al. 2016). Robo-AO uniquely offers the ability to target >15 objects/hr, which has enabled large (>3000 discrete targets) companion star surveys and has resulted in 23 refereed science publications. The most productive large telescope visible AO system is the D=6.5m Magellan telescope AO system (MagAO). MagAO is an advanced Adaptive Secondary Mirror (ASM) AO system at the Magellan 6.5m in Chile (Morzinski et al. 2016). This ASM secondary has 585 actuators with < 1 msec response times (0.7 ms typically). MagAO utilizes a 1 kHz pyramid wavefront sensor. The relatively small actuator pitch (similar to 22 cm/subap) allows moderate Strehls to be obtained in the visible (0.63-1.05 microns). Long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62 microns (r') with the VisAO camera in 0.5" seeing with bright R <= 9 mag stars. These capabilities have led to over 22 MagAO refereed science publications in the visible. The largest (D=8m) telescope to achieve regular visible AO science is SPHERE/ZIMPOL. ZIMPOL is a polarimeter fed by the similar to 1.2 kHz SPHERE ExAO system (Fusco et al. 2016). ZIMPOL's ability to differentiate scattered polarized light from starlight allows the sensitive detection of circumstellar disks, stellar surfaces, and envelopes of evolved AGB stars. Here we review the key steps to having good performance in the visible and review the exciting new AO visible science opportunities and science results in the fields of: exoplanet detection; circumstellar and protoplanetary disks; young stars; AGB stars; emission line jets; and stellar surfaces. The recent rapid increase in the scientific publications and power of visible AO is due to the maturity of the next-generation of AO systems and our new ability probe circumstellar regions with very high (10-30 mas) spatial resolutions that would otherwise require much larger (> 10m) diameter telescopes in the infrared.

La Tesis "Estudio Espectroscópico de la Radiación Electromagnética, Ultravioleta Visible e Infrarroja cercana sobre la Obra Pictórica" de Pablo D'Antoni desarrolla un método no invasivo para caracterizar, medir y predecir daños a los pigmentos y aglutinantes en obras pictóricas, probablemente por la radiación electromagnética (REM). Usando 3 formas de Espectroscopia: 1) Irradiancia, 2) FORS(Espectroscopía de Reflectancia (y Absorbancia) con Fibra Optica, se analizan los efectos producidos por la REM Solar a un grupo de Catas expuestas al sol durante 120 días entre mayo y agosto, desde la 10:00 a las 14:00. Como resultado de la investigación se ha desarrollado a)un método para caracterizar la pintura por su reflectividad en el rango de longitudes de onda de 220 a 850 nm, b) definir el daño commo cambio en la reflectividad de cada color y cuantificarlo como la diferenia entre la condición orgiinal y la condición expuesta (con y sin filtros) en el rango de 220 a 850 nm; c) predecir el daño entrenando modelos matemáticos no lineales con los datos experimentales obtenidos; d) mostrar que algunos de los daños detectados se relacionan con la energía absorvida por un color dado en una o más de las regiones del espectro estudiado. A partir de 2006, el autor ha aplicado este método para: 1) medir la raciación solar Ultravioleta sobre los Angeles Músicos de la Catedral Metropolitana de Valencia, 2 ) "Proyecto I + D de investigacion subencionado por el Ministerior de Ciencia e Innovación otorgado al IVC + R y a la UPV, la iluminacion atenuada del Archivo Dior-Galiano (Richelie, Francia, 3) La emisión de luces del Musée des Arts Décoratifs (Paris), 4) La radiación solar que llega a la Casa de Ariadna (Pompeya, Italia) "proyecto I + D de investigación subvencionado por el Ministerior de Ciencia e Innovación otorgado al IVC + R y a la UPVy 5) Espectroscopia de la Colorimetria de Munsel / D'antoni, PL. (2013). Estudio espectroscópico de la radiación electromagnética ultravioleta, visible e infrarroja cercana sobre la obra pictórica [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/29284 / Palancia

To date, group-III-nitride has undergone continuous improvements to provide a broader range of industrial applications, such as solid-state lighting (SSL), visible light communications (VLC), and light projection. Recently, VLC has attained substantial attention in the field of wireless communication because it offers ~ 370 THz of bandwidth of unregulated visible spectrum, which makes it a critical factor in the evolution of the 5G networks and beyond. GaN-based light-emitting diode (LED) and laser diode (LD) have become increasingly appealing in energy-sufficient SSL replacing conventional light sources. However, III- nitride LEDs suffer from efficiency-droop in their external quantum efficiency associated with high current densities, and their modulation bandwidth is limited to 10 ~ 100 MHz. Although LDs have shown gigabit-modulation bandwidth, unfavorable artifacts, such as speckles are observed, which may raise a concern about eye safety. This dissertation is devoted to the fabrication and electrical and optical characterization of a new class of III-nitride light-emitter known as superluminescent diode (SLD). SLD works in an amplified spontaneous emission (ASE) regime, and it combines several advantages from both LD and LED, such as droop-free, speckle-free, low-spatial coherence, broader emission, high-optical power, and directional beam. Here, SLDs were fabricated by a focused ion beam by tilting the front facet of the waveguide to suppress the lasing mode. They showed a high-power of 474 mW on c-plane GaN-substrate with a large spectral bandwidth of 6.5 nm at an optical power of 105 mW. To generate SLD- based white light, a YAG-phosphor-plate was integrated, and a CRI of 85.1 and CCT of 3392 K were measured. For the VLC link, SLD showed record high-data rates of 1.45 Gbps and 3.4 Gbps by OOK and DMT modulation schemes, respectively. Additionally, a widely single- and dual-wavelength tunability were designed using SLD-based external cavity (SLD-EC) configuration for a tunable blue laser source. These results underscore the practicality of c-plane SLDs in realizing high-power, high data rate, speckle-free, and droop-free SSL-VLC apparatus. Additionally, the SLD-EC configuration allows a wide range of applications, including biomedical applications, optical communication, and high-resolution spectroscopy.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22781号 / 農博第2424号 / 新制||農||1081(附属図書館) / 学位論文||R2||N5301(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 近藤 直, 准教授 小川 雄一, 教授 飯田 訓久 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Visible blue light wavelengths in the 400-470-nm range have been observed to have antimicrobial properties. The purpose of this review article is to delineate the mechanism of action, optimizing conditions, and public health and clinical applications of antimicrobial blue light (aBL) as characterized by the current literature. A widely accepted hypothesis for the mechanism of bacterial inactivation by aBL is that the light causes photoexcitation of endogenous photosensitizers, porphyrins and flavins, which leads to the release of reactive oxygen species that subsequently lead to cell toxicity. Factors that have been observed to be associated with enhanced antimicrobial action include increased duration of exposure, pre-treatment with quinine hydrochloride, and exposure of target bacteria to sub-lethal stress conditions. Studies examining the effect of repetitive exposure to sub-lethal levels of aBL on bacteria show no significant evidence of development of resistance. Additionally, aBL has exhibited the ability to inactivate multidrug-resistant (MDR) bacteria. While studies have also observed aBL to have efficacy in inactivating fungal and viral pathogens, there is a need for further research to elucidate the mechanisms of photoinactivation of fungi and viruses by aBL. Multiple studies have shown that aBL is effective in causing significant CFU reduction in biofilms, an observation that supports the application of aBL for decontamination of surfaces and treatment of localized infections. aBL has demonstrated efficacy in eliminating foodborne pathogens found on food surfaces and exposed surfaces in the food processing environment. Studies applying aBL to decontamination of surfaces in the clinical environment have concluded that it is a viable decontamination practice that shows promise for helping to minimize the spread of healthcare-associated infections (HAIs). Existing literature provides evidence in favor of the application of aBL in clinical contexts such as the treatment of gonococcal infections, eye infections, and otitis media, and in the decontamination of stored platelets and plasma. Studies investigating these clinical applications have demonstrated the efficacy of aBL for inactivating the clinically relevant pathogens, as well as the preservation of normal human cells upon exposure to the doses of light that are lethal to the pathogens. / 2022-11-18T00:00:00Z

In this bachelor project I’m working with a topic close to my heart, in my heart and a matter of the heart. Its about how humans does intimate relationships. Specifically how people in Sweden have relationships that do not follow the monoamorous norm of Swedish society.   This report goes through how one can work with a highly personal topic with the goal to reach out, to awaken awareness and inspire courage in others. How a designer in a student position can have a process that goes back and forth between ”Participating and Listening”, “Talking and Facilitating” and “Thinking and Making”: and how those roles leak into each other, and nurture the over all process.  How did I give visibility to relationship diversity focusing on polyamory and worked withits community? I had a process of searching and experimenting with mediums. Words on twitter and in poems. Gathering people for workshops and conversations. Participating in a polyamourous conference, sending out “Chainletters” among its participants.  Gathering inspiration and information until a materialization was needed. Finding that textile crafts feels as close to home as the topic does. Hands and sewing machines turn intangible into tangible; “My Poly Power Blanket”. The quilted materialization and representation of polyamory goes into our graduation exhibition. Where the blanket gets accompanied by the workshops “Relationship Picnic” and “Make you own Power Patch”. This report gives an overview of the complex process that happened when I worked from my heart, with a subject about hearts; polyamory.

Degradation of organic contaminants in wastewaters emanating from industrial processing plants could render the water streams reusable for the purpose of reducing water consumption while protecting the environment from harmful pollutants. Organic pollutants can be removed from water using biological processes that mineralise the organics to H2O and CO2. However, mineralisation by biological processes take a long time and in many cases, total mineralisation is impossible to achieve. Alternatively, organics can be completely degraded and mineralised rapidly using chemical and/or photocatalytic advanced oxidation processes (AOP). Both systems have some short comings. In chemical AOP such as Fenton and photo-Fenton reagents, the chemical agents used remain in the water as pollutants requiring further removal. In photocatalytic oxidation processes, most current technologies use UV light as an energy source. The chemical processes are environmentally incompatible, whereas, the “green” photocatalysis is extremely expensive due to the consumption of electricity by high pressure UV light. Forerunner investigators of photocatalysis utilised TiO2 as the photocatalyst of choice. It has major drawbacks of which the most important one is that it is only activated under ultraviolet (UV) light irradiation. This high energy consumption made the process practically unfeasible. Solar energy (natural light and heat from sun) has great prospects with regards to acting as a substitute for UV since it is a renewable and cheaper energy source. This work therefore investigated the development of a heterogeneous all-solid-state Z-scheme silver/ silver chloride/ bismuth oxychloride (Ag/AgCl/BiOCl) photocatalyst that is able to utilise natural light through being activated by visible light irradiation. This will successfully serve as a green alternative in the use of renewable energy for pollution reduction while saving energy. The synthesised photocatalysts were characterised using various techniques. The purity and crystallinity of the synthesised photocatalysts were determined using x-ray diffraction (XRD) while x-ray photoelectron spectroscopy (XPS) was used to determine the elemental composition and chemical states present in the synthesised catalysts as well as confirm the presence of elemental Ag. Fourier-transform infrared spectroscopy (FTIR) specified the functional groups present while the morphology and chemical composition were determined on a scanning electron microscopy (SEM)/ energy dispersive x-ray spectroscopy (EDS). The surface area and pore size were measured on a Brunauer-Emmett-Teller (BET) and thermogravimetric analysis (TGA) was done to determine the thermal degradation of synthesised particles. Ultraviolet-visible spectroscopy (UV-VIS) was done to determine the photoabsorption range and bandgap of the particles as efficiency of photocatalysis is dependent on the properties and morphology of the semiconductor material. Degradation studies were carried out under both visible and UV light irradiation in a batch reactor. The activity of the synthesised Ag/AgCl/BiOCl photocatalyst was compared to that of commonly used TiO2. Specifically, while 60% degradation was achieved under UV light irradiation by both TiO2 and Ag/AgCl/BiOCl photocatalyst, in visible light irradiation, TiO2 measures only 14% in 4 h while Ag/AgCl/BiOCl measures a photodegradation efficiency of 53%. Other factors such as initial organic contaminants concentration, initial catalyst concentration, pH effects and individual compounds effect were also investigated. The reusability of the catalyst was also reported showing stability of the synthesised catalyst as after a total irradiation time of 48 h, 65% phenol degradation was measured. The phenol degradation kinetics were found to fit the widely used first-order Langmuir-Hinshelwood model. The result from the current study proves the feasibility of a novel process for mineralisation of organic compounds in water under cost effective visible light irradiation for the removal of recalcitrant and refractory organics from water. / Dissertation (MEng)--University of Pretoria, 2019. / Chemical Engineering / MEng / Unrestricted