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| Registros recuperados: 24 | |
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| Donval, Jean-pierre; Guyader, Vivien. |
| “Headspace” technique is one of the methods for the onboard measurement of hydrogen (H2) and methane (CH4) in deep seawater. Based on the principle of an automatic headspace commercial sampler, a specific device has been developed to automatically inject gas samples from 300 ml syringes (gas phase in equilibrium with seawater). As valves, micro pump, oven and detector are independent, a gas chromatograph is not necessary allowing a reduction of the weight and dimensions of the analytical system. The different steps from seawater sampling to gas injection are described. Accuracy of the method is checked by a comparison with the “purge and trap” technique. The detection limit is estimated to 0.3 nM for hydrogen and 0.1 nM for methane which is close to the... |
| Tipo: Text |
Palavras-chave: Gas; Seawater; Headspace method. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00354/46523/46287.pdf |
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| Donval, Jean-pierre; Charlou, Jean-luc; Lucas, L.. |
| Headspace technique is a common method to analyze light hydrocarbons in deep marine sediments. The use of an automatic headspace sampler instead of a manual injection is the guarantee for a better repeatability and furthermore it is less time consuming. But to increase the sensitivity and therefore, to achieve a better detection limit, it is necessary to optimize the automatic headspace sampler parameters. The theory of design of experiments was applied here by studying them. As a response, methane, which is an important gas in marine sediments, was chosen for its short analysis time. Regarding the parameters for automatic headspace sampler, eight variables were selected and then, a screening of them was carried out with a fractional factorial design to... |
| Tipo: Text |
Palavras-chave: Design of experiments; Headspace technique; Gas; Sediments. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6235.pdf |
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| Franken, Jason R.V.; Parcell, Joseph L.. |
| Increased use of alternative fuels and low commodity prices have contributed to the recent expansion of the U.S. ethanol industry. As with any competitive industry, some level of output price risk exists in the form of volatility; yet, no actively traded ethanol futures market exists to mitigate output price risk. This study reports estimated minimum variance cross-hedge ratios between Detroit spot cash ethanol and the New York Mercantile Exchange unleaded gasoline futures for 1-, 4-, 8-, 12-, 16-, 20-, 24-, and 28-week hedge horizons. The research suggests that a one-to-one cross-hedge ratio is not appropriate for some horizons. |
| Tipo: Journal Article |
Palavras-chave: Cross-hedging; Ethanol; Gas; G13; Q13; Q42. |
| Ano: 2003 |
URL: http://purl.umn.edu/43152 |
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| GENRO, T. C. M.; FARIA, B. M. de; ROSSETTO, J.; CEZIMBRA, I.; SAVIAN, J.; CARVALHO, P. C. de F.; BAYER, C.; BERNDT, A.; SILVA, M. A. P. da; YOKOO, M.; CARDOS, L. L.; OLIVEIRA, P. P. A.; VOLK, L. B. da S.; AMARAL, G. A. do. |
| bitstream/item/110639/1/Genro-et-al.pdf |
| Tipo: Artigo de divulgação na mídia (INFOTECA-E) |
Palavras-chave: Gado de corte; Gas. |
| Ano: 2013 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/998556 |
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| CORRÊA, R. S.; MEDEIROS, J. C.; MADARI, B. E.; CARVALHO, G. D.; COSTA, A. R. da. |
| Os fluxos de N2O oriundos do solo estão entre os mais relevantes para os cálculos das emissões dos GEE. A quantificação das emissões desses gases pelo solo em longos períodos normalmente são realizadas extrapolando-se as emissões mensuradas em uma coleta para todo um período homogêneo. Contudo, para a condição de Cerrado brasileiro, não há trabalhos que faz referência ao melhor horário para a amostragem desses gases. Os objetivos do trabalho consistiram em determinar o horário que melhor representa o fluxo médio diário de N2O em um Latossolo Vermelho cultivado com pastagem na região do Cerrado, verificar qual o tempo máximo antes da saturação deste gás no interior da câmara estática utilizada e comparar o comportamento dos fluxos obtidos por esse método... |
| Tipo: Parte de livro |
Palavras-chave: Cerrado; Gas; Efeito estufa. |
| Ano: 2013 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/984159 |
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| Zanine,Anderson de Moura; Santos,Edson Mauro; Dórea,João Ricardo Rebouças; Dantas,Paulo Alfredo de Santana; Silva,Thiago Carvalho da; Pereira,Odilon Gomes. |
| The objective of this experiment was to evaluate the effects of adding cassava scrapings on gas and effluent losses, dry matter recovery, pH, contents of N-NH3, organic acids and volatile fatty acids and the bromatological composition of elephant grass silages. It was used a randomized complete design, with four levels of cassava scrapings (0, 7, 15 or 30% natural matter) each one with four replications per level. The grass was cut at 50 days of regrowth and ensiled in 15-L silos, equipped with a Bunsen valve to allow gas outflow. The gas losses decreased quadratically with the addition of cassava scrapings, whereas effluent losses decreased linearly. Dry matter recovery increased quadratically with the addition of cassava scrapings. Dry matter (DM)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crude protein; Dry matter; Effluent; Fermentation; Gas. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010001200008 |
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| SAVIAN, J. V.; BARTH NETO, A.; DAVID, D. B. de; BREMM, C.; SCHONS, R. M. T.; GENRO, T. C. M.; AMARAL, G. A. do; GERE, J.; McMANUS, C. M.; BAYER, C.; CARVALHO, P. C. de F.. |
| Tipo: Artigo de periódico |
Palavras-chave: Ovino; Efeito estufa; Gas; Metano. |
| Ano: 2014 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/987863 |
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| ABREU, U. G. P. de; DIAS, F. R. T.; BARIONI, L. G.; FASIABEN, M. do C. R.; LAMPERT, V. do N.; COSTA, F. P.; MOREIRA, J. M. M. A. P.; GOMES, E. G.. |
| This paper aims at evaluating the efficiency of beef cattle productive systems in the Cerrado, Pampa and Pantanal biomes, regarding their emissions intensity (CO2 equivalent per kilogram of carcass weight produced). |
| Tipo: Separatas |
Palavras-chave: Efeito estufa; Gas; Gado de corte; Greenhouse gas emissions; Beef cattle. |
| Ano: 2016 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1057454 |
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| Homem Junior,Antonio Carlos; Ezequiel,Jane Maria Bertocco; Perez,Henrique Leal; Almeida,Marco Tulio Costa; Paschoaloto,Josimari Regina; Carvalho,Vanessa Barbosa de; Cremasco,Leonardo Fernandes; Costa,Macella Borsonello da. |
| Methodological variations in the amount of sample incubated and the type of rumen fluid used are commonly observed. This study evaluated the effect of three sample amounts (0.6, 1.3 or 2.6g DM 100mL-1 of rumen fluid) incubated in rumen fluid buffered (BRF-buffered rumen fluid) or not (PRF-pure rumen fluid) on total gas volume (TV), methane (CH4) production, dry matter degradation (DM Deg) and final pH of corn silage incubated in vitro. The highest DM Deg was reached with the lowest amounts of sample (0.6 and 1.3g of DM 100mL-1 of rumen fluid). The sample amount of 2.6g associated with PRF reduced CH4 production (P<0.05), compared with the amounts of 0.6 and 1.3g DM 100mL-1, which had similar CH4 production (P>0.05). The use of BRF caused no effect on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Degradation; Gas; Incubation; Methane; PH. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015001202229 |
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| ALVAREZ, R. de C. F.; HABERMANN, G.; CRUSCIOL, C. A. C.; NASCENTE, A. S.; RODRIGUES, J. D.. |
| Studies of physiological parameters associated with crop performance and growth in different groups of upland rice (Oryza sativa L.) may support plant breeding programs. We evaluated the role of gas exchange rates and dry matter accumulation (DMA) as traits responsible for yields in a traditional (cv. 'Caiapó'), intermediate (cv. 'Primavera') and modern (cv. 'Maravilha') upland rice cultivars. Leaf gas exchange rates, DMA, leaf area index (LAI), harvest indexes (HI) and yield components were measured on these genotypes in the field, under sprinkler irrigation. Panicles per m2 and DMA at flowering (FL) and heading, as well as CO2 assimilation rates (A) were similar across these cultivars. The highest yield was found in ?Primavera?, which may be explained by... |
| Tipo: Artigo de periódico |
Palavras-chave: Índice de colheita; Intercâmbio de gases; Arroz; Oryza sativa; Gas; Fisiologia; Harvest index; Gas exchange; Rice. |
| Ano: 2015 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1017076 |
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| Popescu, Irina; De Batist, Marc; Lericolais, Gilles; Nouze, Herve; Poort, Jeffrey; Panin, Nicolae; Versteeg, Wim; Gillet, Herve. |
| A previously unknown pattern of multiple bottom-simulating reflections (BSRs) occurs on high-resolution reflection seismic data in the Danube deep-sea fan, associated with acoustic features indicating free gas. Our study provides evidence that this pattern is developed in relation with the architecture of distinct channel-levee systems of the Danube fan. Channel-levee systems hosting multiple BSRs act as relatively sealed gas-bearing systems whose top is situated above the base of the gas hydrate stability zone (BGHSZ). Inside these systems, free gas accumulates below the BGHSZ under a combined lithological, structural and stratigraphical control. The uppermost BSR marks the current equilibrium BGHSZ, for a gas composition of more than 99% methane.... |
| Tipo: Text |
Palavras-chave: Black Sea; Deep sea fan; Seismic data; Gas; Gas hydrates; Bottom simulating reflections. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1210.pdf |
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| Baltzer, Agnès; Tessier, Bernadette; Nouze, Herve; Bates, R; Moore, C; Menier, D. |
| The presence of gas is a common feature in many seismic sections. However, the origin of the gas is often difficult to determine. Recently acquired very high resolution seismic profiles using an IKB Seistec boomer provide useful insight to the understanding of the gas origins in a range of environmental settings including sea lochs and coastal lagoons. The gas features are described both from a qualitative point of view through their acoustic facies, and quantitatively through the associated seismic signal (polarisation, amplitude). Acoustic facies include acoustic turbidity, gas "curtains" and "blankets" as well as "white fringes" and "black shadows". All the features encountered have been related to specific gas nature generated by different sources... |
| Tipo: Text |
Palavras-chave: Signal amplitude; Signal polarisation; Gas; Acoustic facies; Seistec profiles. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-835.pdf |
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| Baltzer, Agnes; Reynaud, Marine; Ehrhold, Axel; Fournier, Jerome; Cordier, Celine; Clouet, Helene. |
| About a decade ago, a large field of pockmarks, covering an overall area of 36 km(2) was discovered in water depths of < 30m in the central part of the Bay of Concarneau (Southern Brittany, France). This field, composed of features from 5 m to 35 m in diameter and < 1 m in depth, is characterized by unusual high densities of pockmarks, up to 5840 per square kilometre. Geophysical data correlated with sedimentary samples acquired in 2005 and 2009 show that pockmarks and their immediate surroundings are associated with dense tubes benches cover, built by a filter-feeding amphipod: Haploops nirae, forming original benthic communities. Two complementary surveys were carried out in April 2011 (Pock and Ploops) and April 2014 (Pock and Tide), on the... |
| Tipo: Text |
Palavras-chave: Géophysique; Marée; Failles; Gaz; Geophysics; Pockmarks; Tide; Turbidity; Gas; Chimneys pipes; Concarneau. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00410/52107/52938.pdf |
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| Registros recuperados: 24 | |
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