4,755 research outputs found
Recovery of p-TBC from a butadiene washing stream in a pilot plant
Results obtained in a pilot-scale unit designed for COD removal and p-TBC (p-tert-butylcatechol) recovery from a butadiene washing stream (pH 14, 200,000 mg COD L-1, highly toxic) at a petrochemical industry are presented. By adding H3PO4, phase separation is achieved and p-TBC is successfully recovered (88 g L-1 of washing stream). Information (time for phase separation and organic phase characterization) was gathered for designing a future industrial unit. The estimated heat generation rate was 990 kJ min-1 and 15 min were enough to promote phase separation for a liquid column of approximately 1.15 m.PetroflexCNPqFUJ
Validação de modelos de estimativa de produtividade de milho, feijão, arroz e trigo no Brasil.
A Embrapa Informática Agropecuária produz anualmente uma vasta gama de informação tanto bibliográfica, de natureza técnico-científica, quanto referencial. No entanto, as mudanças ocorridas na sociedade devido aos impactos das novas tecnologias de informação e de comunicação exigem da Empresa Brasileira de Pesquisa Agropecuária (Embrapa) novos procedimentos para organização da informação disponível, de forma que resulte em efetiva transferência de tecnologia. Some-se a isso do fato de que a Embrapa Transferência de Tecnologia gerencia, hoje, uma vasta carteira de clientes, desde produtores rurais a cooperativas, que demandam continuamente por novas informações e tecnologias para garantir a evolução de seus negócios. Através da integração de modelos de simulação de crescimento e de desenvolvimento de culturas, bases de dados de clima e de solo, prognósticos de tempo e de clima, técnicas de análise regional e ferramentas de geoprocessamento, acoplados a um serviço eficiente de monitoramento agrometeorológico, é possível produzir um eficiente sistema de monitoramento da produtividade das culturas em escala local e regional.bitstream/item/32638/1/Doc110-1.pd
Tolerância de três acessos de Brachiaria spp. ao alagamento do solo, em condições controladas.
O excesso de água no solo em pastagens tropicais é a principal condição para instalação da síndrome da morte do capim Brachiaria brizantha cv. Marandu. Assim, objetivou-se comparar a tolerância relativa de três genótipos de Brachiaria: B. humidicola cv. Comum, B. humidicola cv. LIanero e B. brizantha cv. Marandu, ao alagamento do solo. As plantas foram cultivadas em vasos, sob alagamento do solo, em casa de vegetação, na Embrapa Amazônia Oriental, Belém (PA). O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 3 x 2, com cinco repetições. As produções de folhas, colmos e de massa seca total não foram reduzidas pelo alagamento do solo na cultivar LIanero, sendo mais reduzidas na cultivar Marandu. Todos os genótipos testados tiveram a produção de massa seca de raízes diminuída pelo alagamento do solo, porém, com maior intensidade na cultivar Marandu. Conclui-se que B. brizantha cv. Marandu foi o acesso mais afetado pelas condições de alagamento, sendo a cultivar LIanero a mais tolerante
TiO2-Photocatalyzed degradation of phenol in saline media in an annular reactor: hydrodynamics, lumped kinetics, intermediates, and acute toxicity
The photocatalytic degradation of phenol in aqueous suspensions of TiO2 under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen-Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.(FAPERJ) Fundacao de Amparo a Pesquisa do Estado do Rio de JaneiroFUJBCNPqPADC
Fe-bearing phases in Antarctic carbonaceous chondrites Yamato-82162 and Yamato-86720: A Mossbauer study
We report the results of variable temperature Mossbauer spectroscopy measurements on samples of Yamato-82162 and Yamato-86720 carbonaceous chondrites. Transmission Mossbauer spectra were taken through the temperature range from 4.2K to 300K. The Mossbauer spectra at room temperature clearly indicate the presence of magnetic splits and quadrupole doublets in both meteorites, which can be attributed to troilite and olivine, respectively. The measurements also indicate the presence of a superparamagnetic component, probably ferryhidrite, in Y-86720 but not in Y-82162. These results are mostly consistent with those obtained by mineralogical studies. However, our Mossbauer measurements indicate the presence of a previously unknown magnetic component having a field of 250kOe in both meteorites; the mineral is unidentified so far. Our study supports the view that these meteorites were affected by thermal metamorphism, and that Y-82162 was less thermally metamorphosed than Y-86720
Creatine Supplementation Improves Muscular Performance without Additional Impact on the Cardiovascular System in Trained Women
Creatine monohydrate supplementation in females is largely under-represented in the literature, and their potentially differential hemodynamic responses are unknown. Methods: Twenty-eight resistance-trained women (25.5 ± 6.1 years, 59.7 ± 6.3 kg, 163 ± 5 cm) were randomly assigned to the supplement creatine monohydrate (CRE; 5 g creatine monohydrate + 5 g dextrose) or placebo (PLA; 10 g dextrose) four times per day for 7 days in a double-blind fashion. Each subject subsequently completed resistance training sessions (3 × week) for four weeks with four sets to muscular failure of both half-squat and leg press exercises. The change in body mass (BM), exercise repetition number (REP), rated perceived exertion (RPE), and cardiovascular variables were assessed (sessions 1, 6, and 12). Statistical analyses were performed at a significance level of p ≤ 0.05. Results: Analyses revealed a significant CRE-specific BM increase (p = 0.013), as well as significantly greater half-squat (p = 0.006) and leg press (p = 0.017) REP per set versus PLA. Additionally, CRE demonstrated significantly lower relative RPE values at session 12 compared with previous sessions. Any significant main or interaction effects were observed for the studied cardiovascular variable. Conclusions: The present data substantiate the creatine’s efficacy to improve muscular performance in females while demonstrating the safety of combined creatine monohydrate supplementation and resistance training on cardiovascular parameters
Ultrasound and dynamic functional imaging in vascular cognitive impairment and Alzheimer's disease
The vascular contributions to neurodegeneration and neuroinflammation may be assessed by magnetic resonance imaging (MRI) and ultrasonography (US). This review summarises the methodology for these widely available, safe and relatively low cost tools and analyses recent work highlighting their potential utility as biomarkers for differentiating subtypes of cognitive impairment and dementia, tracking disease progression and evaluating response to treatment in various neurocognitive disorders. METHODS: At the 9th International Congress on Vascular Dementia (Ljubljana, Slovenia, October 2015) a writing group of experts was formed to review the evidence on the utility of US and arterial spin labelling (ASL) as neurophysiological markers of normal ageing, vascular cognitive impairment (VCI) and Alzheimer's disease (AD). Original articles, systematic literature reviews, guidelines and expert opinions published until September 2016 were critically analysed to summarise existing evidence, indicate gaps in current knowledge and, when appropriate, suggest standards of use for the most widely used US and ASL applications. RESULTS: Cerebral hypoperfusion has been linked to cognitive decline either as a risk or an aggravating factor. Hypoperfusion as a consequence of microangiopathy, macroangiopathy or cardiac dysfunction can promote or accelerate neurodegeneration, blood-brain barrier disruption and neuroinflammation. US can evaluate the cerebrovascular tree for pathological structure and functional changes contributing to cerebral hypoperfusion. Microvascular pathology and hypoperfusion at the level of capillaries and small arterioles can also be assessed by ASL, an MRI signal. Despite increasing evidence supporting the utility of these methods in detection of microvascular pathology, cerebral hypoperfusion, neurovascular unit dysfunction and, most importantly, disease progression, incomplete standardisation and missing validated cut-off values limit their use in daily routine. CONCLUSIONS: US and ASL are promising tools with excellent temporal resolution, which will have a significant impact on our understanding of the vascular contributions to VCI and AD and may also be relevant for assessing future prevention and therapeutic strategies for these conditions. Our work provides recommendations regarding the use of non-invasive imaging techniques to investigate the functional consequences of vascular burden in dementia
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