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A computational fluid dynamics study of hydrogen bubbles in an electrochemical reactor BABT
Cavalcanti,Renata da Silva; Farias Neto,Severino Rodrigues de; Vilar,Eudésio Oliveira.
Most electrochemical reactors present reactions with the growth and departure of gas bubbles which influence on the reactor hydrodynamics and this study is usually complex, representing a vast field for research. The present paper had as objective to study a bi-phase (gas-liquid) system aiming to foresee the influence of departure of hydrogen bubbles generated on effective electrode surface situated on cathodic semi-cell. Nevertheless, it was idealized that the gas was injected into the semi cell, through the effective electrode surface With this hypothesis, it was possible to study, and numerically analyze, the hydrodynamic behavior of the hydrogen bubbles in the interior of the study domain, applying concepts of computational fluid dynamics by using the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hydrogen; Bubble; CFD; Finite volumes; Electrochemical reactor.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000400027
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Comunidades del zooplankton en los ríos Teaone, Esmeraldas, Terminal Petrolero y el balneario Las Palmas de Esmeraldas, durante el 2004 OceanDocs
Naranjo, Ch..
Los estudios del zooplancton en diferentes áreas principalmente en el río Teaone, Esmeraldas y la zona marino costera frente a la ciudad que incluye, el área del balneario Las Palmas, en el último año se ha intensificado con el objetivo de obtener un conocimiento detallado de la presencia de estos organismos y las características físico-químicas que condicionan su abundancia y distribución.
Tipo: Journal Contribution Palavras-chave: Community composition; Zooplankton; Biological production; Salinity; Hydrogen; Water quality; Temporal variations; Species diversity; Zooplankton; Biological production; Water quality; Salinity; Hydrogen; Species diversity; Http://aims.fao.org/aos/agrovoc/c_15490; Http://aims.fao.org/aos/agrovoc/c_36649; Http://aims.fao.org/aos/agrovoc/c_16061; Http://aims.fao.org/aos/agrovoc/c_6751; Http://aims.fao.org/aos/agrovoc/c_3724; Http://aims.fao.org/aos/agrovoc/c_33954.
Ano: 2005 URL: http://hdl.handle.net/1834/2372
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Cyanobacterial nitrogenases: phylogenetic diversity, regulation and functional predictions Genet. Mol. Biol.
Esteves-Ferreira,Alberto A.; Cavalcanti,João Henrique Frota; Vaz,Marcelo Gomes Marçal Vieira; Alvarenga,Luna V.; Nunes-Nesi,Adriano; Araújo,Wagner L..
Abstract Cyanobacteria is a remarkable group of prokaryotic photosynthetic microorganisms, with several genera capable of fixing atmospheric nitrogen (N2) and presenting a wide range of morphologies. Although the nitrogenase complex is not present in all cyanobacterial taxa, it is spread across several cyanobacterial strains. The nitrogenase complex has also a high theoretical potential for biofuel production, since H2 is a by-product produced during N2 fixation. In this review we discuss the significance of a relatively wide variety of cell morphologies and metabolic strategies that allow spatial and temporal separation of N2 fixation from photosynthesis in cyanobacteria. Phylogenetic reconstructions based on 16S rRNA and nifD gene sequences shed light on...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Cyanobacteria; Evolution; Hydrogen; Nitrogen fixation; Molecular phylogeny.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000200261
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Differences in gas venting from ultramafic-hosted warm springs: the example of Oman and Voltri Ophiolites ArchiMer
Boulart, Cedric; Chavagnac, Valerie; Monnin, Christophe; Delacour, Adelie; Ceuleneer, Georges; Hoareau, Guilhem.
Serpentinisation of mantle rocks, leading to natural venting of hydrogen and methane, has been reported to occur at the global scale, wherever fluids percolate in ultramafic formations. Here we compare gas composition from two on-land, low-temperature, and hyper-alkaline springs hosted on ultramafic rocks in the ophiolite massifs of the Sultanate of Oman and the Ligurian Alps (Voltri Group, Genoa region, Northern Italy). These two settings exhibit similar chemical and mineralogical features but show diverse styles of gas venting. Commonly to all hyper-alkaline springs, gases are characterised by relatively high N-2, very low O-2 and CO2 concentrations, and a strong enrichment in H-2 and CH4. The comparison between Oman and Liguria highlights a high...
Tipo: Text Palavras-chave: Methane; Hydrogen; Gas composition; Hyper-alkaline springs. Oman; Voltri Massif.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00175/28634/27059.pdf
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DIGESTÃO ANAERÓBIA DO GLICEROL ORIUNDO DA PRODUÇÃO DO BIODIESEL: ALTERNATIVAS PARA GERAÇÃO DE ENERGIA E PRODUTOS DE ALTO VALOR AGREGADO Repositório Alice
VIANA, M. B..
O presente estudo teve como objetivo avaliar o glicerol proveniente de biodiesel como substrato para síntese de hidrogênio (H2), metano (CH4) e ácidos carboxílicos através de digestão anaeróbia. Inicialmente, foram realizados testes de bancada alimentados em batelada com a finalidade de avaliar o efeito da relação substrato/micro-organismo (S0/X0) na produção de H2. Os valores de S0/X0 testados variaram entre 1 e 16 g de demanda química de oxigênio (DQO)/g de sólidos totais voláteis (STV). Na segunda etapa da pesquisa, a produção de H2 foi avaliada variando-se a fonte de inóculo (lodo floculento proveniente de estação de tratamento de esgoto sanitário ? ES, lodo granular proveniente de estação de tratamento de efluente de cervejaria ? EC, líquido ruminal...
Tipo: Tese/dissertação (ALICE) Palavras-chave: 1 3 propanediol; Ácido n caproico; Glicerina; Hidrogênio; Metano; Hydrogen; Methane.
Ano: 2016 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1101791
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Effect of hydrogen uptake (Hup) characteristics on survival of Bradyrhizobium japonicum (Buchanan 1980) comb. Nov. in flooded soil International Rice Research Institute
Maskey, Surya Laxmi (Joshi).
119 l. : ill. Thesis (Ph.D.) -- University of the Philippines at Los Baños
Tipo: Thesis Palavras-chave: Rhizobium; Soil; Flooded conditions; Hydrogen; Rice; Soybeans; Cropping systems; Bradyrhizobium japonicum.
Ano: 1990 URL: http://hdl.handle.net/123456789/1017
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ESTUDOS ECOLÓGICOS DE COMUNIDADES MICROBIANAS TRATANDO GLICEROL EM CONDIÇÕES ANAERÓBIAS PELA APLICAÇÃO DE BIOLOGIA MOLECULAR Repositório Alice
VASCONCELOS, E. A. F. de.
Técnicas de biologia molecular aplicadas em digestão anaeróbia permitem estudar a ecologia microbiana e estrutura de comunidades em biorreatores. O glicerol é um subproduto da transesterificação e pode ser usado para produzir hidrogênio por digestão anaeróbia, portanto, conhecer as interações microbianas permite compreender a relação entre os fatores biológicos, operacionais e funcionais, aperfeiçoando os processos envolvidos e o desempenho do sistema. Esta pesquisa teve como objetivo estudar as variações de diversidade, riqueza e organização funcional da comunidade microbiana, relacionando os parâmetros ecológicos, operacionais, a funcionalidade e a produtividade de reatores anaeróbios. Reatores UASB hidrogênicos foram operados e monitorados, sob aumentos...
Tipo: Tese/dissertação (ALICE) Palavras-chave: PCR DGGE; Digestão Anaeróbia; Hidrogênio; Microbial ecology; Bioreactors; Hydrogen.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1101766
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Evaluation of Techniques That Measure Hydrogen and Methane Levels in Breaths of Horses with Gastrointestinal Diseases OAK
SASAKI, Naoki; FUKUNAKA, Morito; YAMADA, Haruo; SENBA, Hiroyuki; HIGUCHI, Tohru; 佐々木, 直樹.
Techniques for measuring hydrogen (H2) and methane (CH4) levels in breaths were assessed in horses with gastrointestinal (GI) diseases. A total of 31 horses were studied: 11 healthy horses (Group A), 10 horses with GI diseases (Group B), and 10 horses with diseases without GI involvement (Group C). Expired gases were measured using gas chromatography. CH4 levels in Group A were significantly lower than those in Group B. In Group B, CH4 levels were significantly higher after treatment. Fluctuations in H2 and CH4 levels in breath were associated with changes in GI function.
Palavras-chave: Equine; Hydrogen; Methane.
Ano: 2006 URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3102
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Feasibility of biohydrogen production from industrial wastes using defined microbial co-culture Biol. Res.
Chen,Peng; Wang,Yuxia; Yan,Lei; Wang,Yiqing; Li,Suyue; Yan,Xiaojuan; Wang,Ningbo; Liang,Ning; Li,Hongyu.
BACKGROUND: The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step...
Tipo: Journal article Palavras-chave: Renewable Energy; Biohydrogen; Microbial consortium; Hydrogen.
Ano: 2015 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602015000100024
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Fermentative hydrogen production from agroindustrial lignocellulosic substrates BJM
Reginatto,Valeria; Antônio,Regina Vasconcellos.
To achieve economically competitive biological hydrogen production, it is crucial to consider inexpensive materials such as lignocellulosic substrate residues derived from agroindustrial activities. It is possible to use (1) lignocellulosic materials without any type of pretreatment, (2) lignocellulosic materials after a pretreatment step, and (3) lignocellulosic materials hydrolysates originating from a pretreatment step followed by enzymatic hydrolysis. According to the current literature data on fermentative H2 production presented in this review, thermophilic conditions produce H2 in yields approximately 75% higher than those obtained in mesophilic conditions using untreated lignocellulosic substrates. The average H2 production from pretreated material...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fermentation; Hydrogen; Lignocellulosic substrates; Pretreatment; Inhibitors.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822015000200323
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Microbial hydrogen production potential in shallow oceanic nepheloid layers. ArchiMer
Schwarz, J; Loeblich, L; Schropp, S.
Seawater samples taken from shallow suspended particle maxima (20-57m) at or near the base of the surface mixed layer in various oceanic areas were tested for their potential to produce hydrogen (H sub(2)) gas. Results suggest that hydrogen can be bacterially produced through a fermentative process in microanaerobic niches within particulate matter. The organisms responsible for this process are ubiquitous within the temperate and tropical waters sampled. Enumeration of potential H sub(2)-producing bacteria using fluorescent antibody techniques yielded a maximum at the base of the surface mixed layer, the same depth where the greatest H sub(2) gas production potential was observed. Hydrogen-producing bacteria comprised up to 15% of the total bacterial...
Tipo: Text Palavras-chave: Suspended particulate matter; Sea water; Gases; Biogeochemistry; Biogenic material; Hydrogen; Anaerobic bacteria; Nepheloid layer; Fermentation.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-962.pdf
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Photoproduction d'hydrogene par une souche de bacteries phototrophes sulfureuses marines ArchiMer
Matheron, R; Baulaigue, R.
H sub(2) evolution from sulfur and organic compounds by Ectothiorhodospira) strain BA1011 has been investigated. Ectothiorhodospira strain BA1011 produces hydrogen from sulfide, thiosulfate and some organic acids such as propionate, acetate, lactate and succinate. Major characteristics are defined from sulfide: experiments show a correlation between photohydrogen production and CO sub(2) assimilation as well as an increase of the utilization of endogeneous and exogeneous organic substrates with sulfide as electron donor.
Tipo: Text Palavras-chave: Ectothiorhodospira; Bacteria; Hydrogen; Photochemistry; Photochemical reactions.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-969.pdf
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Simultaneous effects of pH and substrate concentration on hydrogen production by acidogenic fermentation Electron. J. Biotechnol.
Cubillos,Genoveva; Arrué,Ramon; Jeison,David; Chamy,Rolando; Tapia,Estela; Rodríguez,Jorge; Ruiz-Filippi,Gonzalo.
The present research examined the effects of initial substrate concentration and pH on the yield and productivity of hydrogen production by acidogenic fermentation. Assays were carried out at three different initial pH levels (5.5, 6.5 and 7.5) and three initial substrate concentrations (3, 5 and 10 g COD/L). Glucose was used as carbon source and the experiments were conducted at 37°C in batch tests, after a thermal pretreatment to eliminate methanogenic microorganisms. Conversions of glucose into hydrogen were between 16.75 and 27.25% of theoretical maximum, and high values of hydrogen productivity were obtained. An optimum value for the yield of glucose between initial pH of 6.3 and 3.7 g COD/L and productivity of the 5.95 H2/gVSS h and initial pH of 6.7...
Tipo: Journal article Palavras-chave: Acidogenic; Gompertz modified; Heat treatment; Hydrogen; Surface response.
Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582010000100011
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