ABSTRACT Introduction Obsessive-Compulsive Disorder (OCD) is a common psychiatric pathology, classically considered chronic and debilitating because of the significant impact it can have on overall patient functionality, including at work. Its etiology is still unclear, and the clinical presentation is quite heterogeneous, manifesting itself through obsessions and/or compulsions that are associated with high levels of anxiety and time consumption. Case Report A 40-year-old female, working as an administrative assistant in a hospital, with a history of almost 20 years of obsessive doubt and verification rituals. Due to the worsening of symptoms, and their high impact on work capacity, she started a psychiatry follow-up. Then, according to the employee’s expectations and limitations, she was transferred to a different workstation, with less social interactions and different responsibilities. Subsequently, after both interventions, significant clinical improvement was shown. Discussion The close relationship between Occupational Medicine and Psychiatry, unequivocally contributes to manage mental illness in the workplace, either identifying reasonable adjustments to meet the needs of workers with mental illness, or attending the ones noticed during their regular activities. Conclusion It is essential to implement strategies for effective communication between both medical specialities, and aim to prevent occupational risks, by protecting and promoting healthy workplaces.

RESUMO Introdução A Perturbação Obsessivo-Compulsiva (POC), é uma patologia psiquiátrica comum, classicamente considerada crónica e incapacitante, pelo impacto significativo que pode apresentar na funcionalidade global dos doentes, inclusivamente a nível laboral. A sua etiologia está ainda pouco esclarecida e a apresentação clínica é bastante heterogénea, manifestando-se através de obsessões e/ou compulsões que se associam a elevados níveis de ansiedade e de consumo de tempo. Descrição do caso Trata-se de uma doente do sexo feminino, com 40 anos de idade, assistente técnica num centro hospitalar, que apresentava um quadro de dúvida obsessiva e rituais de verificação com cerca de vinte anos de evolução. Por agravamento da sintomatologia, com elevado impacto na funcionalidade laboral, iniciou acompanhamento pela especialidade de Psiquiatria. Concomitantemente, atendendo às expetativas e limitações desta trabalhadora, ela foi realocada a um posto de trabalho que permitisse recrutamento das suas capacidades organizativas, mas menor interação social e responsabilidade direta. Na sequência deste conjunto de intervenções, objetivou-se uma melhoria clínica global significativa. Discussão A articulação estreita entre a Medicina do Trabalho e a Psiquiatria, contribui de forma inequívoca para a gestão de casos de trabalhadores com patologia psiquiátrica, quer na adaptação das funções às eventuais condicionantes que daí decorram, quer na orientação de casos de doença psiquiátrica detetados durante o exercício das suas funções. Conclusão Afigura-se indispensável a delimitação de estratégias para uma comunicação eficaz entre estas especialidades, com vista à prevenção dos riscos profissionais, proteção e promoção da saúde no local de trabalho.

Hypovolemia induced by hemorrhage is a common clinical complication, which stimulates vasopressin (AVP) secretion by the neurohypophysis in order to retain body water and maintain blood pressure. To evaluate the role of brain L-glutamate and angiotensin II on AVP secretion induced by hypovolemia we induced hemorrhage (∼25% of blood volume) after intracerebroventricular (icv) administration of AP5, NBQX, or losartan, which are NMDA, AMPA, and AT1 receptor antagonists, respectively. Hemorrhage significantly increased plasma AVP levels in all groups. The icv injection of AP5 did not change AVP secretion in response to hemorrhage. Conversely, icv administration of both NBQX and losartan significantly decreased plasma AVP levels after hemorrhage. Therefore, the blockade of AMPA and AT1 receptors impaired AVP secretion in response to hemorrhage, suggesting that L-glutamate and angiotensin II acted in these receptors to increase AVP secretion in response to hemorrhage-induced hypovolemia.

Resumo Desde os estudos clássicos de Alexander Flemming, as cepas de Penicillium são conhecidas como uma fonte rica em substâncias antimicrobianas. Estudos recentes identificaram novos metabólitos produzidos pela espécie Penicillium sclerotiorum com atividades antibacteriana, anti-incrustante e farmacêutica. Aqui, relatamos o isolamento de uma colônia de P. sclerotiorum (LM 5679) do solo amazônico e relatamos também o estudo baseado em cultura para determinar se ele pode produzir qualquer novo metabólito (s) secundário (s) que não foram relatados até agora para este gênero. Usando um sistema de cultura submerso, os metabólitos secundários foram recuperados por extrato de solvente seguido por cromatografia em camada delgada, ressonância magnética nuclear e espectroscopia de massa. Um novo metabólito secundário foi isolado de P. sclerotiorum (LM 5679); o composto fenólico 5-pentadecil resorcinol que é amplamente conhecido como um antifúngico que é produzido por diversas espécies de plantas. Este metabólito não foi relatado anteriormente em nenhuma espécie de Penicillium, e foi encontrado apenas uma vez em fungos (Fusarium). Aqui, discutimos as atividades conhecidas do 5-pentadecil resorcinol no contexto de seu modo de ação como um estressor hidrofóbico (mediado pela caotropicidade).

Abstract Since the classic studies of Alexander Flemming, Penicillium strains have been known as a rich source of antimicrobial substances. Recent studies have identified novel metabolites produced by Penicillium sclerotiorum that have antibacterial, antifouling and pharmaceutical activities. Here, we report the isolation of a P. sclerotiorum (LM 5679) from Amazonian soil and carry out a culture-based study to determine whether it can produce any novel secondary metabolite(s) that are not thus-far reported for this genus. Using a submerged culture system, secondary metabolites were recovered by solvent extract followed by thin-layer chromatography, nuclear magnetic resonance, and mass spectroscopy. One novel secondary metabolite was isolated from P. sclerotiorum (LM 5679); the phenolic compound 5-pentadecyl resorcinol widely known as an antifungal, that is produced by diverse plant species. This metabolite was not reported previously in any Penicillium species and was only found once before in fungi (that time, in a Fusarium). Here, we discuss the known activities of 5-pentadecyl resorcinol in the context of its mode-of-action as a hydrophobic (chaotropicity-mediated) stressor.

Resumo Hortaliças contaminadas com resíduos fecais são importantes vias de transmissão de parasitas intestinais ao homem. O objetivo deste estudo foi avaliar a presença de formas parasitárias de protozoários e helmintos em alface (Lactuca sativa) e couve (Brassica oleracea) vendidas em feiras e supermercados na cidade de Aparecida de Goiânia, Goiás, Brasil. Um total de 30 amostras de cada vegetal (15 amostras de supermercados e 15 de feiras livres) foi analisado. Todas as amostras foram processadas pelos métodos de sedimentação espontânea e centrífugo-flutuação. Em 45% das amostras foram identificadas formas imaturas de parasitas intestinais sendo 66,7% ovos de helmintos e 33,3% de cistos ou oocistos de protozoários. Significativamente, mais amostras de alface estavam contaminadas com ovos, cistos ou oocistos de pelo menos um parasita do que as amostras de couve (U = 216; Z = -3,45; P <0,001). As formas parasitárias foram identificadas morfologicamente ao nível de família com ovos de Ancylostomatidae, Strongyloididae, Ascarididae e Taeniidae ou oocistos de Eimeriidae, dos gêneros Cystoisospora sp. e Toxocara sp., e ao nível de espécies com Cystoisospora canis, Dipylidium caninum e Hymenolepis nana. A presença desses agentes infecciosos em alface e couve, provenientes tanto de feiras quanto de supermercados, ressalta o alto risco de veiculação de parasitas pela ingestão de hortaliças cruas comercializadas em Aparecida de Goiânia.

Abstract Foliar vegetables contaminated with fecal residues are an important route of transmission of intestinal parasites to humans. The aim of this study was to evaluate the presence of parasitic forms of protozoa and helminths on lettuces (Lactuca sativa) and collard greens (Brassica oleracea) sold in street- and supermarkets in the city of Aparecida de Goiânia, Goiás, Brazil. A total of 30 samples of each vegetable (15 samples from each supermarkets and street markets) was analyzed. All samples were processed by spontaneous sedimentation method and centrifugal flotation. In 45% of the samples, immature forms of intestinal parasites were identified with 66.7% helminths eggs and 33.3% protozoan cysts or oocysts. Significantly more lettuce samples were contaminated with eggs, cysts or oocyst of at least one parasite than collard green samples (U=216; Z=-3.45; P <0.001). The parasitic forms were identified morphologically up to the family level with eggs of Ancylostomatidae, Strongyloididae, Ascarididae and Taeniidae, or oocysts of Eimeriidae, to the genus with Cystoisospora sp. and Toxocara sp., and to the species level with Cystoisospora canis, Dipylidium caninum and Hymenolepis nana. The presence of these infective agents in lettuce and collard green from both street- and supermarkets highlights the high risk of spreading parasites by eating raw vegetables sold in Aparecida de Goiânia.

Resumo Atualmente, os anestésicos disponíveis para peixes podem produzir efeitos colaterais importantes, incluindo parada respiratória e sofrimento. Alternativas de fácil implementação e baixa toxicidade são necessárias para garantir a saúde dos peixes, bem como para auxiliar a pesca artesanal e os vendedores de pescado no manuseio e transporte do pescado, e as plantas nativas parecem ser a melhor alternativa. Nosso objetivo foi implementar um protocolo anestésico utilizando extratos etanólicos brutos de flores e folhas de duas plantas amazônicas, Acmella oleracea e Piper alatabaccum. Primeiro testamos os extratos para anestesia, usando o peixe-zebra como modelo. Embora em alguns tratamentos os animais aparentemente tenham entrado em anestesia profunda, muitos deles apresentaram comportamentos aberrantes e até morreram. Assim, realizamos novos experimentos testando os efeitos dos extratos em epilepsia dos peixes. Apenas o extrato de folhas de A. oleracea tem efeitos potenciais para anestesia de peixes. Tanto o extrato de flores desta planta quanto o extrato de folhas de P. alatabaccum induziram um comportamento semelhante a convulsões nos animais. Em conclusão, além de trazer um possível novo protocolo anestésico para peixes, nosso trabalho chama a atenção para os efeitos neurotóxicos que as soluções anestésicas podem causar, uma vez que vários estudos defendem outras espécies de Piper como anestésico para peixes e o extrato de flores de A. oleracea já foi apontado como anestésico para peixe.

Abstract Currently, available fish anesthetics can produce important side effects, including respiratory arrest and distress. Easy-to-implement alternatives with low toxicity are needed to ensure fish health as well as to help artisanal fisheries and fish sellers in handling and transporting fishes, and native plants seems to be the best alternative. We aimed to implement an anesthetic protocol using crude ethanolic extracts from flowers and leaves of two Amazonian plants, the Acmella oleracea and Piper alatabaccum. We first tested the extracts for anesthesia, using the zebrafish as model. Even though in some treatments the animals apparently entered deep anesthesia, many of them presented aberrant behaviors and even died. Thus, we performed new experiments testing the extracts effects on seizure-like behaviors of the fish. Only the leaf extract of A. oleracea has potential effects for fish anesthesia. Both the flower extract from this plant and the leaf extract from P. alatabaccum induced seizure-like behavior in the animals. In conclusion, besides bringing a possible new anesthetic protocol for fish, our work draws attention for the neurotoxic effects the anesthetic solutions may cause, since several studies defend other Piper species as anesthetic for fish and A. oleracea flowers’ extract was already pointed as fish anesthetic.

Resumo No Brasil, as estruturas de concreto armado projetadas com base na NBR 6118 [1] devem ser verificadas em situação de incêndio pela NBR 15200 [2], a qual propõe diferentes métodos de verificação. No caso de vigas, tem-se como alternativa o método tabular e o simplificado, entre outros. O objetivo deste artigo foi realizar uma comparação entre ambos os métodos, por meio da aplicação de seus critérios em vigas isostáticas e hiperestáticas, de seção 20x50 cm, projetadas à temperatura ambiente pela NBR 6118 [1]. A distribuição de temperatura nas seções foi obtida por programa computacional. Os resultados apontaram que, no caso estudado, o método simplificado apresentou tempos de resistência ao fogo (TRF) superior em 75% dos casos, mas não superiores a 30 minutos em relação ao método tabular. O método simplificado permitiu otimizar resultados, apesar do maior tempo para o dimensionamento.

Abstract In Brazil, reinforced concrete structures designed based on NBR 6118 [1] must be assessed in fire conditions through NBR 15200 [2], which proposes multiple test methods. Concerning beams, this standard offers the tabular and simplified methods as possible choices. This study aimed to compare these two methods by applying their principles to isostatic and hyperstatic beams with section of 20x50 cm, designed at room temperature according to NBR 6118 [1]. The temperature distribution along sections was obtained by means of a software program. The results from this study indicated that the simplified method yielded higher fire-resistance ratings (FRR) in 75% of cases, although not surpassing the tabular method by 30 minutes. The simplified method allowed an optimization of the results, despite the longer design time.

A eficiência reprodutiva em bovinicultura é um objetivo fundamental para a viabilização económica das explorações, determinando no atual quadro comunitário de apoios o montante das ajudas aos produtores. Entre janeiro de 2012 e setembro de 2015, foram avaliados através de exame andrológico, 223 bovinos machos com idades compreendidas entre os 13 e 156 meses, em 35 explorações de bovinos de carne, no interior centro e sul de Portugal. Cerca de 57% dos exames foram efetuados nos meses de setembro a dezembro, devido à maior procura deste serviço por parte dos produtores, de modo a preparar a época de cobrição sequente. Foram avaliados touros das raças: Limousine, Charolesa, Alentejana, Mertolenga e Cruzados, dos quais foram aprovados 72,6%, reprovados 14,8% e foi recomendada a reavaliação a 12,6%. No âmbito da avaliação do esperma, para os parâmetros motilidade massal e individual, mais de 50% dos touros avaliados apresentaram esperma de muito boa qualidade (classes 4 e 5 de motilidade); e, 91% dos reprovados apresentaram esperma de má qualidade. Em 95% dos animais aprovados, a condição corporal foi considerada adequada. Entre os reprovados, 15% apresentaram condição corporal inadequada. Considerando duas classes de idade média, 36% dos machos aprovados, tinham menos de 24 meses de idade. Entre os reprovados, apenas 6% apresentaram idade inferior a 24 meses e 56% tinha idade superior a 5 anos. De entre os animais classificados para reavaliação (n=28), apenas 12 foram reavaliados e destes, 50% foram reclassificados em aprovados. Baixa a nula fertilidade foi revelada em 21% dos animais, com uma perda económica evidentemente associada e reforçada pela sua permanência em épocas de cobrição sucessivas. Os animais reprovados podem afetar até 1.645 vacas, o que se traduz em perdas potenciais de rendimento estimadas em 770.000€.

Reproductive efficiency in cattle is important in the economic viability of farms. Currently, this efficiency is evident in determining the amount of aid to be received by producers. Between January 2012 and September 2015 were evaluated 223 breeding bulls through breeding soundness examination with ages between 13 and 156 months in 35 beef cattle farms in the center and south of Portugal. About 57% of the examinations were performed from September to December, due to higher demand for this service by producers, in order to prepare the time of mating. Bulls of breeds Limousin, Charolais, Alentejana, Mertolenga and their Crosses were evaluated and 72.6% were approved, 14.8% disapproved and recommended a reassessment to 12.6%. In sperm evaluation scope, for mass and individual motility, more than 50% of the sample sperm have a very good quality (grades 4 and 5 motility); 91% of reprobates have poor quality sperm. In 95% of approved bulls, body condition is adequate. And among those who failed, 15% had inadequate body condition. Considering age, 36% of approved bulls were less than 24 months old. Among the bulls that failed to be approved, only 6% were younger than 24 months and 56% were older than 5 years of age. Among the bulls qualified for revaluation (n=28), only 12 were reassessed and of these 50% was reclassified as approved. 21% of the bulls have low fertility and consequently an economic loss, and in this case, affecting up to 1,645 cows, which results in a € 770.000 potential loss.

Abstract This study assessed the feasibility of an anaerobic sequencing batch and fed-batch biofilm reactor (AnSBBR) with mechanical stirring for vinasse treatment and biomethane production. The amount of liquid medium used was 3 L, and the treated volume was 1 L per cycle. The cycle time was 8 h, with feeding times of 10 min (batch mode) and 240 min (fed-batch mode). Methane productivity increased with the increase in organic load from 1.0 to 10.0 gCOD.L-1.d-1. The maximum molar productivity and yield of methane were 123.4 molCH4.m-3.d-1 and 13.8 mmolCH4.gCOD-1 (88% of the theoretical), respectively. These parameters were lower in fed-batch mode than in batch mode and were lower at 45°C than at 30°C due to biomass adaptation. In general, the values of the kinetic parameters increased with organic load and were similar for the batch and fed-batch modes. Therefore, the increase in organic load positively influenced the process by increased COD removal and lower volatile acids accumulation as the load increased. The batch mode performed better than did the fed-batch mode and 30°C was more suitable than 45°C to produce methane under the studied conditions.

Abstract Biogas production is becoming increasingly important in the environmental area because, besides treating wastewaters, it also generates energy. Co-digestion has become more and more powerful since it is possible, with the use of abundant and cheap substrates, to dilute the inhibitory effects of various other substrates, making the process of anaerobic digestion more efficient and stable. Biogas process modelling describes the kinetics and stoichiometry of different steps in the anaerobic digestion process. This mathematical modelling provides an understanding of the processes and interactions occurring inside the biogas system. The present work investigated the interactions between different simple co-substrates (carbohydrate, lipid and protein) and real co-substrates (corn silage, fodder beet, grass and wheat straw) under co-digestion with manure, in order to verify synergetic effects. Subsequently, some experiments were reproduced, in order to evaluate the synergy obtained in the previous simulation and validate the model.

Resumo A qualidade dos grãos abrasivos é fundamental para o aumento da vida útil das ferramentas de desbaste, polimento e corte. Nesse contexto, o presente trabalho teve como objetivo avaliar as variáveis de tratamento térmico do óxido de alumínio eletrofundido marrom na obtenção do óxido de alumínio "blue fired". Este é um grão abrasivo com melhores propriedades físicas, em relação ao óxido de alumínio eletrofundido marrom e que apresenta uma coloração azulada, característica essa exigida pelo mercado de abrasivos. Desta forma, este trabalho aborda o processo de eletrofusão da bauxita até a obtenção do "blue fired", assim como faz uma comparação do índice de resistência à fratura deste material com aquele dos óxidos de alumínio eletrofundido marrom convencionais. Esse índice se relaciona com o recíproco da friabilidade. Além dos teores dos óxidos de titânio e de ferro, as variáveis tempo, temperatura e atmosfera, aos quais o material é submetido, são parâmetros fundamentais a serem controlados a fim de se obter um grão abrasivo dentro dos padrões exigidos, como foi comprovado experimentalmente neste trabalho. A coloração da alumina eletrofundida é justificada por fenômenos óticos de transição eletrônica e não pela formação da fase titanato de alumínio, como algumas explicações encontradas na literatura técnica afirmam. Além disso, ficou demonstrado que essa coloração não deve ser utilizada como indicativo das características abrasivas ótimas desta classe de óxido de alumínio.

Abstract The quality of abrasive grains is crucial to increase the lifespan of roughing, polishing and cutting tools. The purpose of the work herein was to evaluate the variables of the blue fired aluminum oxide heat treatment process. This heat treatment process improves the physical properties of the brown fused aluminum oxide and results in a blue coloring, which uniquely identifies it within the abrasives industry. The work herein includes information beginning with the electro-fusion process of bauxite (the manufacturing of the brown fused aluminum oxide) to the Blue Fired process. It also compares the fracture resistance index between these materials. This index is the inverse of the friability. Besides the content of titanium and iron oxides, process variables such as time, temperature and atmospheric conditions are important to monitor in order to reach standard requirements. Experimental evidence measuring these parameters is presented in the article herein. The blue coloring of this aluminum oxide is explained by the optical phenomena of electron transition, and not by the formation of aluminum titanate, as some technical literature has stated. Furthermore, it was proved that the coloring of blue fired material should not be used exclusively as an indicator of the optimal abrasive characteristics of this class of aluminum oxide.

Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6). Exposure to methylmercury (0-100 μM) was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h) also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.

AbstractAn AnSBBR (anaerobic sequencing batch reactor containing biomass immobilized on an inert support) with liquid phase recirculation, containing a 3.5 L working volume, treated 1.5 L of cheese whey wastewater in 3 and 4 h cycles at 30 ºC to produce biohydrogen. From startup the bioreactor presented process instability. To overcome this problem the following measures were taken, however without success: adaptation of the biomass with uncontaminated easily degradable substrates, pH control at very low levels, and a different form of inoculation (natural fermentation of the feed medium). The problem was solved by cooling the feed medium to 4 ºC to prevent acidification in the storage container, by eliminating nutrient supplementation to prevent possible formation of H2S by sulfate-reducing bacteria and by periodic washing of the support material to improve the food/microorganism ratio. Hence, stable hydrogen production could be achieved with minimal presence of methane (36% H2; 62% CO2; 2% CH4) and the AnSBBR fed with cheese whey (influent concentration of 4070 mgCOD.L-1 and 3240 mgCarbohydrate.L-1 and applied volumetric organic loading of 14.6 gCOD.L-1.d-1) presented improved productivity and yield indicators compared to pure lactose and other reactor configurations, reaching values of 420 NmLH2.L-1.d-1 and 0.60 molH2.molCarbohydrate-1 in the steady-state phase (conversions of carbohydrates and COD were 98% and 30%, respectively).

A tenacidade à fratura, K IC, é uma importante propriedade dos materiais cerâmicos, pois ela mede a resistência ao início da propagação de trinca. O problema é selecionar o método adequado para determinar K IC, já que existem vários, cada um com suas particularidades. Por comodidade, escolhe-se o método da indentação, IF, que apresenta certos inconvenientes, principalmente para cerâmicas porosas, Sendo o método mais adequado, o SEVNB. Nesse trabalho são mostrados resultados de K IC para três materiais: carbeto de silício (SiC), alumina (Al2O3) e um a base de argila, uma telha cerâmica. Os resultados mostraram que os valores de K IC são maiores quando é utilizado o método IF, sendo que quanto mais porosa é a cerâmica mais difícil é a aplicação desse método, e que o método SEVNB, pode ser aplicado com êxito. Os resultados de K IC, medidos pelo método SEVNB são 3,8 MPa.m½, 2,5 MPa.m½ e 0,4 MPa.m½ para SiC, Al2O3 e telha, respectivamente.

Fracture toughness, K IC, which measuresthe resistance tocrack propagation initiation of a pre-cracked body, is oneof the most importantpropertiesof ceramic materials. The main problemis to selectthe most appropriate methodto determinethis property,since there areseveral ones, each of them with its own characteristics. Normally, for convenience, the indentationmethod is chosen. It is the IF (Indentation Fracture) method, which measures the cracksizeat the verticesof the indentation. However, that methodhas many drawbacks, especially ifthe ceramic material isporous, since itisvery difficulttoidentify the extent of the propagated crack. Themost suitable methodformeasuring fracture toughnessis the SEVNB(Single Edge V NotchBeam). This paper describesK ICresultsfor threedifferent materials: silicon carbide, SiC, alumina, Al2O3, and a clay based ceramics, ceramic tile, with distinctporosities.The results indicate that thevalues of K ICare higherwhen theIF method is used, and the moreporous theceramicsis,the more difficult it is to applythis method. On the other hand, the SEVNB method, regardless porosity, can be applied successfully.The K ICvaluesmeasuredby the SEVNBmethodwere3.8 MPa.m½, 2.5 MPa.m½ and0.4 MPa.m½forSiC, Al2O3and ceramic tile, respectively.

A deterioração de refratários utilizados em unidades fluidizadas de craqueamento catalítico (UFCC) é responsável por altos custos de manutenção para a indústria petroquímica. Esse fenômeno é comumente associado à deposição de coque durante a produção de hidrocarbonetos. Entretanto, outros mecanismos causadores de dano podem ocorrer, como a geração de defeitos por transição de fase expansiva. O objetivo deste trabalho foi estudar a contribuição da transição de fase a-b de partículas de quartzo para a deterioração de um refratário comercial sílico-aluminoso empregado em riser de UFCC, por meio de ciclos térmicos lentos. Este dano pode ocorrer caso a temperatura de operação do equipamento oscile ao redor da temperatura da transição a-b (573 °C). Este estudo foi realizado no material com e sem coque impregnado, visando avaliar o efeito conjunto da presença do coque e da transformação de fase. Para a avaliação do dano empregou-se a medida do módulo de Young em função da temperatura através da Técnica de Excitação por Impulso em atmosfera controlada. Para tal, utilizou-se um equipamento recentemente desenvolvido no grupo de pesquisa dos autores. Foram preparados corpos de prova do material e estes foram submetidos a ciclos térmicos lentos com temperaturas máximas de 500 °C e 700 °C com taxa de aquecimento de 2 °C/min. Uma parcela destes corpos foi previamente impregnada por coque em reator de propeno. Complementarmente, ensaios de difração de raios X, de dilatometria e a observação com microscopia eletrônica foram realizados. Comprovou-se que as partículas de quartzo são determinantes para o comportamento termomecânico do material e para a resistência ao dano por ciclagem térmica. A transição de fase a-b, embora enrijeça o material no aquecimento, intensifica o dano por ciclo térmico lento. A impregnação pelo coque aumenta a resistência a ciclos térmicos lentos, porém reduz a resistência à evolução do dano.

The deterioration of refractories used in fluidized catalytic cracking units (FCC-units) is responsible for high costs of maintenance for the petrochemical industry. This is commonly associated with coke deposition during the production of light hydrocarbons. However, other mechanisms responsible for causing damage may also occur, such as the generation of cracks by expansive phase transition. The aim of the work herein was to study the contribution of the a-b phase transition of quartz particles to the deterioration of a commercial aluminosilicate refractory used in a riser by the means of slow thermal cycles. Such damage may occur if the working temperature of the equipment fluctuates around the a-b transition temperature (573 °C). The current study considered the material with and without coke impregnation to evaluate the combined effect of coke presence and phase transition. To evaluate the damage, it was used the Young's modulus as a function of temperature by applying the Impulse Excitation Technique under controlled atmosphere. An equipment recently developed by the authors research group was applied. Specimens were prepared and submitted to slow thermal cycles of temperatures up to 500 °C and up to 700 °C, with a heating rate of 2 °C/min. Part of the specimens was previously impregnated with coke by a reactor using propen. To complete the evaluation, characterization by X-ray diffraction, as well as by dilatometry and scanning electron microscopy were performed. The findings of this study showed that the presence of quartz particles determine the thermo-mechanical behaviour of the material, as well as the thermocycling damage resistance. In spite of the fact that the a-b phase transition stiffens the material during the heating stage, it increases the damage by slow thermal cycling. The coke impregnation increases the resistance to slow thermal cycles, however it decreases the resistance to the damage evolution.

An anaerobic sequencing batch biofilm reactor (AnSBBR) containing immobilized biomass and operating with recirculation of the liquid phase (total liquid volume 4.5 L; treated volume per cycle 1.9 L) was used to treat sucrose-based wastewater at 30 ºC and produce biohydrogen. The influence of applied volumetric organic load was studied by varying the influent concentration at 3600 and 5400 mgCOD.L-1 and using cycle lengths of 4, 3 and 2 hours, obtaining in this manner volumetric organic loads of 9, 12, 13.5, 18 and 27 gCOD.L-1.d-1. Different performance indicators were used: productivity and yield of biohydrogen per applied and removed load, reactor stability and efficiency based on the applied and removed organic loads, both in terms of organic matter (measured as COD) and carbohydrate (sucrose). The results revealed system stability (32-37% of H2 in biogas) during biohydrogen production, as well as substrate consumption (12-19% COD; 97-99% sucrose). Conversion efficiencies decreased when the influent concentration was increased (at constant cycle length) and when cycle lengths were reduced (at constant influent concentrations). The best yield was 4.16 mol-H2.kg-SUC-1 (sucrose load) at 9 gCOD.L-1.d-1 (3600 mgCOD.L-1 and 4 h) with H2 content in the biogas of 36% (64% CO2 and 0% CH4). However, the best specific molar productivity of hydrogen was 8.5 molH2.kgTVS-1.d-1 (32% H2; 68% CO2; 0% CH4), at 18 gCOD.L-1.d-1 (5400 mgCOD.L-1 and 3 h), indicating that the best productivity tends to occur at higher organic loads, as this parameter involves the "biochemical generation" of biogas, whereas the best yield tends to occur at lower and/or intermediate organic loads, as this parameter involves "biochemical consumption" of the substrate. The most significant metabolites were ethanol, acetic acid and butyric acid. Microbiological analyses revealed that the biomass contained bacilli and endospore filaments and showed no significant variations in morphology between different experimental conditions.