Three students working on a project in the Air Conditioning and Refrigeration Department of the New York Trade School

This shows three students working on a unit in the Air Conditioning and Refrigeration Department of the New York Trade School. Black and white photograph.

View of drafting section in Air Conditioning Department of the New York Trade School

Students are shown working in the drafting section of the Air Conditioning Department of the New York Trade School. Black and white photograph that has some damage around the edges.

Air Conditioning Students at Work

Four students from the New York Trade School are pictured working on an air conditioning unit. Photograph is black and white.

Sambandet mellan bestrykningsrecepturoch sänkningen av ytansvithet vid UV-lackning

AssiDomän tillverkar kartong till förpackningsindustrin. Inom detta område är vitheten på kartongytanen viktig parameter. För att höja intrycket av förpackningen samt skapa en skyddande yta lackas ofta förpackningen med UV-lack efter tryck. Efter lackning kan då otryckta lackade ytor uppfattas som mindre vita. För att ta reda på om bestrykningssammansättningen har betydelse har ett fem olika bestrykningar blandats. Pigmenten som använts i bestrykningarna är karbonat, kaolin och titandioxidi olika kombinationer. Kartong har sedan bestrukits med dessa och därefter lackerats med UV-lack. Lackningen har gjorts i tre olika lackmängder. Mätningar har sedan gjorts gällande framförallt vithet. Den samverkan som sker mellan ljus, materialet och dess struktur är av stor vikt för att skapa en yta med goda optiska egenskaper. Resultaten i detta försök visar att lacken påverkar de optiska egenskaperna och framförallt vitheten. De lackerade ytorna fick en gulton efter lackering vilket kan ha att göra med lackens egenskaper. Vitheten hade en något mindre minskning för den bestrykning som bestod av karbonat och titandioxid. Skillnaden var dock mycket liten då alla bestrykningar fick en sänkning av vitheten med cirka 11-13 procentenheter oberoende av utgångsvärdet i vithet för respektive bestrykning innan lackning. Positivt var att det kunde konstateras att den bestrykning som hade det högsta vithetsvärdet före lackning också hade det efter lackning med ett normalt lackpålägg vilket betyder att en hög vithet är av betydelse även om den bestrukna ytan ska lackas. Den sänkning av vitheten som sker kan ha flera tänkbara orsaker. En tänkbar orsak kan vara att lacken förstör den porösa struktur som ger den viktiga ljusspridningen i bestrykningsskiktet. Resultaten visar också att lackens egenskaper tycks vara av stor betydelse. Den gulton som framträdde efter lackning tyder på en ökad absorption av vissa ljusvåglängder. Något som också pekar på detta är att alla fem bestrykningarna fick en liknande sänkning av vitheten. För att säga exakt vad som är orsaken eller vilken kombination som påverkar vitheten mest krävs ytterliggare tester. Olika UV-lacker kan testas eftersom endast en UV-lack har använts i dessa försök. En närmare studie av gränsyta mellan UV-lacken och bestrykningsskiktet bör också göras för att se hur lacken påverkar bestrykningsskiktets struktur.

Investigation of Iron (III) desferrioxamine B oxalate ligand exchange by UV-vis spectroscopy: the next step in developing a quantitative analytical method for measuring bioavailable iron in marine ecosystems

To date there are no analytical techniques designed to exclusively measure bioavailable iron in marine environments. The goal of this research is to develop such a technique by isolating the bioavailable iron using the terrestrial siderophore desferrioxamine B (DFB). This project contained many challenging aspects, but the specific goal of this study was to develop a robust analytical technique for quantification of Fe(III)-DFB complexes at nanomolar concentrations. Past work showed that oxalate (Ox) promotes photodissociation of Fe(III)-DFB to Fe(Il), and we are specifically interested in the mechanism of this process. A model was developed using known thermodynamic constants for Fe(III)-DFB and Fe(III) oxalato complexes and adjusting for ionic strength. The model was confirmed by monitoring the UV-VIS absorbance of the system at a variety of oxalate concentrations and pH. The model did not include ternary complexes. Next., the rate of Fe(1I) production during UV irradiation was examined. The results showed that the rate of Fe(II) production was based entirely on the [Fe(Ox)?]3- speciation, and that reoxidation of Fe(II) occurred via reactive oxygen intermediates. This reoxidation could be avoided by either decreasing the oxygen concentration or by adding a Fe(II) stabilizing reagent, such as ferrozine. Further studies need to be done to confirm that these results apply at sub nanomolar concentrations, and the issue of Fe(II) reoxidation at lower Fe concentrations needs to be addressed.

Avaliação da transmitância direta de resinas compostas por meio de espectrofotometria de UV-visível

Este estudo avaliou as porcentagens de Transmitância direta (Td) das resinas compostas microhíbridas Charisma F, Solitaire II (Heraeus Kulzer ), Intens e Tetric Ceram (Ivoclar Vivadent) e nanoparticuladas Esthet-X (Dentsply De trey) e Filtek Supreme (3M Espe) nas cores Vita A3 (Dentina) e translúcido (Esmalte), ou seus correspondentes. Foram confeccionados três corpos-de-prova para cada material e cor, de formato quadrangular com 12x12 mm de lado e espessura de 1 mm. Após fotoativação, foram realizadas três leituras por corpo-de-prova em espectrofotômetro de UV-visível HP 8453 (Hewlett-Packard), com temperatura e umidade controladas (22±2°C/50±5%). Os ângulos de incidência e leitura em 0° / 0° foram utilizados para os comprimentos de onda de 400 a 700 nm. Os espectros obtidos foram analisados quanto ao percentual médio de Td para todo o espectro, em intervalos de 20 nm, e nos comprimentos de onda de 400, 560 e 700 nm. Através de ANOVA e teste de Tukey (p=0,01) encontrou-se que a resina composta Charisma obteve as maiores porcentagens de Td em todos os espectros, exceto para a cor Esmalte em 700 nm, que ficou abaixo da resina composta Esthet-X cor Esmalte. O teste t-Student demonstrou serem significativamente maiores os percentuais de Td para os espectros das cores Translúcido, exceto para as resinas compostas Supreme, em que não diferiram, e Charisma, com porcentagens de Td significativamente maiores para a cor Dentina. Por meio de teste não paramétrico de Friedman verificou-se que todas as resinas compostas estudadas demonstraram aumento significativo de Td com o aumento do comprimento de onda, com exceção da resina composta Solitaire, cores Dentina e Esmalte, que não demonstrou diferenças significativas nos comprimentos de onda de 560 e 700 nm.

Contribuição ao estudo do envelhecimento de ligantes asfálticos : influência da adição de polímeros e comportamento frente a radiação uv

A malha rodoviária brasileira apresenta-se, em sua maior extensão, em má condições de serventia. Uma das alternativas para se evitar deformações permanentes e trincamentos no pavimento é a adição, a quente e em reatores especiais, de polímeros ao asfalto. Esta prática já é realizada no Brasil há alguns anos, porém ainda não se tem um domínio do assunto, principalmente no caso da modificação de ligantes asfálticos brasileiros. O objetivo deste trabalho é avaliar a influência de algumas propriedades do polímero modificador no envelhecimento do ligante asfáltico modificado. Para tanto se realizou inicialmente um estudo sobre o mecanismo de envelhecimento de ligantes puros, inclusive frente a radiação ultravioleta do sol, e em seguida utilizou-se a mesma metodologia para avaliar o papel do polímero neste processo. Além disso, relacionou-se através de um projeto de experimentos a massa molar e teor de estireno do polímero SBS linear com suas propriedades clássicas, estabilidade, temperatura de transição vítrea e morfologia. Observou-se que a simulação de envelhecimento UV em laboratório, desenvolvida neste estudo, foi extremamente satisfatória. Os processos de foto-oxidação e termooxidação resultam em mecanismos diferentes de envelhecimento. A origem e composição química dos ligantes é de suma importância no mecanismo de envelhecimento UV destes. A massa molar e o teor de estireno do polímero modificador representam propriedades importantes para a estabilidade e durabilidade do ligante asfáltico modificado.

Fenólicos totais, polifenoloxidade e coloração em abacate 'Hass' submetido a radiação UV-C

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da radiação uv, temperatura e vapor aquecido nos compósitos poliméricos: monitoramento, instabilidade estrutural e fratura

The application of composite materials and in particular the fiber-reinforced plastics (FRP) has gradually conquered space from the so called conventional materials. However, challenges have arisen when their application occurs in equipment and mechanical structures which will be exposed to harsh environmental conditions, especially when there is the influence of environmental degradation due to temperature, UV radiation and moisture in the mechanical performance of these structures, causing irreversible structural damage such as loss of dimensional stability, interfacial degradation, loss of mass, loss of structural properties and changes in the damage mechanism. In this context, the objective of this thesis is the development of a process for monitoring and modeling structural degradation, and the study of the physical and mechanical properties in FRP when in the presence of adverse environmental conditions (ageing). The mechanism of ageing is characterized by controlled environmental conditions of heated steam and ultraviolet radiation. For the research, it was necessary to develop three polymer composites. The first was a lamina of polyester resin reinforced with a short glass-E fiber mat (representing the layer exposed to ageing), and the other two were laminates, both of seven layers of reinforcement, one being made up only of short fibers of glass-E, and the other a hybrid type reinforced with fibers of glass-E/ fibers of curaua. It should be noted that the two laminates have the lamina of short glass-E fibers as a layer of the ageing process incidence. The specimens were removed from the composites mentioned and submitted to environmental ageing accelerated by an ageing chamber. To study the monitoring and modeling of degradation, the ageing cycles to which the lamina was exposed were: alternating cycles of UV radiation and heated steam, a cycle only of UV radiation and a cycle only of heated steam, for a period defined by norm. The laminates have already undergone only the alternating cycle of UV and heated steam. At the end of the exposure period the specimens were subjected to a structural stability assessment by means of the developed measurement of thickness variation technique (MTVT) and the measurement of mass variation technique (MMVT). Then they were subjected to the mechanical tests of uniaxial tension for the lamina and all the laminates, besides the bending test on three points for the laminates. This study was followed by characterization of the fracture and the surface degradation. Finally, a model was developed for the composites called Ageing Zone Diagram (AZD) for monitoring and predicting the tensile strength after the ageing processes. From the results it was observed that the process of degradation occurs Abstract Raimundo Nonato Barbosa Felipe xiv differently for each composite studied, although all were affected in certain way and that the most aggressive ageing process was that of UV radiation, and that the hybrid laminated fibers of glass-E/curaua composite was most affected in its mechanical properties

Ratios of UV, PAR and NIR components to global solar radiation measured at Botucatu site in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of estradiol benzoate microinjection into the median raphe nucleus on contextual conditioning

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Migration of Tinuvin P, a UV stabilizer, from PET bottles into fatty-food simulants

Tinuvin P migration from Polyethyleneterephthalate (PET) bottles was investigated using several fatty-food simulants such as olive oil, soybean oil, n-heptane and iso-octane, at exposure conditions of 2-10 days at 40 degrees C (total immersion). The stability of several UV stabilizers (BHT, Cyasorb UV 5411, Tinuvin P, Tinuvin 326 and Tinuvin 327) in n-heptane and iso-octane was also studied. After 10 days at 40 degrees C, losses of 6% and 20% in iso-octane and n-heptane respectively, were verified for Tinuvin P. Other UV stabilizers at the same experimental conditions showed higher losses (up to 30% for Tinuvin 327). These results confirm that, when carrying out specific migration studies, the stability of the substance of interest should be established in the food simulant to avoid underestimating the real migration behaviour. In order to quantify UV stabilizer migration, n-heptane and iso-octane solutions were concentrated and directly analysed by SIM mode GC-MS. For olive and soybean oils, Tinuvin P was isolated using size-exclusion chromatography and quantified by SIM mode GC-MS. Iso-octane proved to be a move suitable fatty-food simulant than n-heptane for the migration study of Tinuvin P from PET. Higher levels of Tinuvin P migrated to olive and soybean oils rather than to n-heptane. These results suggest that the MERCOSUL recommended official methods for specific migration studies should be revised since the migration levels using n-heptane as a fatty-food simulant could be underestimated when compared to edible oils. Copyright (C) 1999 John Wiley & Sons, Ltd.

Development and Validation of an UV-Derivative Spectrophotometric Method for Determination of Glimepiride in Tablets

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rapid and Selective UV Spectrophotometric Method for the Analysis of Ceftazidime

A new UV spectrophotometric method was developed for quantitative evaluation of ceftazidime preparations. The UV detector was set at 255 nm. Beer's law is obeyed in the concentration range of 7.0-14.0 mu g/mL. The method was found to be selective, linear, accurate, and precise in the specified ranges. Intra- and interday variability for the method were <2% relative standard deviation. Common excipients used as additives in pharmaceutical preparations do not interfere with the proposed method. This method was successfully used for quantification of ceftazidime in pure form and in pharmaceutical preparations.