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| Registros recuperados: 43 | |
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| Donoso-Bravo,Andrés; Carballa,Marta; Ruiz- Filippi,Gonzalo; Chamy,Rolando. |
| In this work, an anaerobic sequencing batch reactor (ASBR) was operated for 8 months to treat low strength sewage with high suspended organic matter content. Three phases of operation with increasing organic loading rates (OLR) were performed: 0.4 kg COD/m³ x d (phase I), 0 .8 kg COD/m³ x d (phase II) and 1.2 kg COD/m³ x d (phase III). Adequate stability parameters (pH, total alkalinity) were obtained through all three experimental phases. During phases I and II, the removal efficiencies of organic matter (expressed as total chemical oxygen demand (COD) and total suspended solids ranged between 50-60%. However, these values decreased to 15-25% in phase III. In addition, a non-complex model, including hydrolysis, acidogenesis and methanogenesis, was applied... |
| Tipo: Journal article |
Palavras-chave: Acidogenesis; Anaerobic treatment; Hydrolysis; Low strength wastewater; Modeling. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582009000300013 |
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| Spyridon,Achinas; Willem Euverink,Gerrit Jan. |
| Bioethanol production is one pathway for crude oil reduction and environmental compliance. Bioethanol can be used as fuel with significant characteristics like high octane number, low cetane number and high heat of vaporization. Its main drawbacks are the corrosiveness, low flame luminosity, lower vapor pressure, miscibility with water, and toxicity to ecosystems. One crucial problem with bioethanol fuel is the availability of raw materials. The supply of feedstocks for bioethanol production can vary season to season and depends on geographic locations. Lignocellulosic biomass, such as forest-based woody materials, agricultural residues and municipal waste, is prominent feedstock for bioethanol cause of its high availability and low cost, even though the... |
| Tipo: Journal article |
Palavras-chave: Bioconversion; Bioethanol; Fermentation; Hydrolysis; Renewable fuels. |
| Ano: 2016 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000500009 |
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| ROMERA, C. M.; SANTOS, C. F. dos; TURATI, D. F. M.; NAKAI, D. K.; JUNGMANN, L.; MENDES, T. D.; PACHECO, T. F.; RODRIGUES, D. de S.. |
| Resumo: Um dos principais desafios da coleta e extração de óleo de frutos de dendê (palma de óleo) é a manutenção da qualidade do óleo, de forma a evitar a liberação de ácidos graxos, que mudam as propriedades do óleo e, consequentemente, reduzem seu valor comercial. A liberação desses ácidos é atribuída à ação de lipases. Entretanto, não há um consenso quanto à fonte das enzimas que hidrolisam excessivamente o óleo, se ela é endógena (produzida pelo próprio fruto de dendê) ou exógena (produzida por um determinado microrganismo que colonizou o fruto de dendê). Neste trabalho, a verificação da presença de lipases no mesocarpo de frutos de dendê foi realizada por meio de reações de hidrólise. Dessa maneira, as proteínas contidas no mesocarpo de dendê foram... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Frutos de dendê; Palma de óleo; Dendê; Ácido Graxo; Lípase; Hidrolise; Acidificação; Palm oils; Hydrolysis; Acidification; Fatty acids. |
| Ano: 2021 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1132216 |
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| Le Gac, Pierre-yves; Choqueuse, Dominique; Melot, D.. |
| Polymers are widely used for passive thermal insulation coatings on steel pipe in offshore oil and gas production. In this industry, structures used in deep sea have to be reliable, as they are in service for more than 20 years in a very severe environment: sea water, hydrostatic pressure and temperature gradient. One of the main questions is how to test and predict the lifetime of such structures in the laboratory? This study presents one approach that has been developed to characterize and predict the degradation of polymers used as thermal insulation materials. This paper is dedicated to polyurethane (polyether based) degradation in sea water at high temperature. Ageing has been performed in natural sea water under hydrostatic pressure at temperatures... |
| Tipo: Text |
Palavras-chave: Polyurethane; Hydrolysis; Accelerated ageing; Sea water; Coating; Offshore. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00160/27132/25330.pdf |
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| Derombise, Guillaume; Van Schoors, Laetitia Vouyovitch; Messou, Marie-fleur; Davies, Peter. |
| Aramid fibers are high-performance materials which have been used in ropes and protective clothing for many years. They are also now being proposed in geo-textiles for ground reinforcement. The influence of the surface finish composition and content has been studied in the field of cables and textiles, but there is no published data concerning the effect of a finish treatment on the hydrolytic degradation. Aramid fibers with different finish contents have been aged in an alkaline environment. The degradation has been identified by FTIR, viscosimetry, TGA, SEM, and tensile tests. For Technora fibers, the presence of finish appears to limit the tensile strength loss of aramid fibers at pH 11 by limiting abrasion, as well as bulk and surface degradation. For... |
| Tipo: Text |
Palavras-chave: Aramids; Fibers; Aging; Finish; Hydrolysis. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00006/11702/8987.pdf |
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| Hoppe, H. |
| Extracellular enzymes mediate the decomposition of polymeric organic compounds in natural waters. In many cases these enzymes comprise a component linked to the bacterial fraction of the aquatic community and react in close association with these cells. An annual survey of microbial activities in a brackish water fjord exhibited an excellent correlation between V sub(m) of proteases (ability to split the substrate analogue methylumbelliferyl-leucine) and V sub(m) as well as T sub(R) for leucine uptake by microorganisms. Hydrolysis rates (H sub(R)) for the decomposition of naturally occurring competitive substrate analogues of the model substrates (methylumbelliferyl-(MUF)-leucine, MUF- alpha -D-glucose, MUF-N-acetyl-glucosamine, MUF-phosphate) drastically... |
| Tipo: Text |
Palavras-chave: Biogeochemistry; Fjords; Bacteria; Brackishwater environment; Seasonal variations; Dissolved organic matter; Interspecific relationships; Hydrolysis; Enzymes. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-952.pdf |
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| Dumay, Justine; Donnay-moreno, Claire; Barnathan, G; Jaouen, P; Berge, Jean-pascal. |
| Enzymatic hydrolysis of sardine viscera by three broad spectrum proteases was investigated using the pHstat method (24 h, pH 8, 50 degrees C). After hydrolysis, three fractions (sludge, aqueous phase and oily phase) were collected. For each fraction, lipids and phospholipids were quantified and molecular weights of aqueous phase peptides were determined. Under these conditions, the degree of hydrolysis (DH) varied from 1.9% (Flavourzyme), 3.1% (Protamex) and to 3.3% (Alcalase). Dry matter distribution indicated that all hydrolysis performed increased solubilisation of proteins: protein recovery for each hydrolysis ranged from 57.4% to 61.2%. Furthermore, the total lipid content in the liquid parts (oily and aqueous phases) increased (at least 85% of lipids... |
| Tipo: Text |
Palavras-chave: Fish protein hydrolysate FPH; Sardine; By product; Lipid; Hydrolysis; Phospholipid. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2004.pdf |
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| Le Gac, Pierre-yves; Choqueuse, Dominique; Melot, D.; Melve, B.; Meniconi, L.. |
| Polymers are widely used for passive thermal insulation coatings on steel pipe in offshore oil and gas production. In this industry, structures used in deep sea have to be reliable as they are in service for more than 20 years in a very severe environment: sea water, hydrostatic pressure, temperature. One of the main questions is how to test and predict the lifetime of such structures in the laboratory. This study presents one approach that has been developed to characterize and predict the degradation of polyurethanes used as thermal insulation materials. Based on results obtained during accelerated ageing of the PU in sea water, a prediction of degradation through the thickness has been set up taking into account the temperature profile in the coating,... |
| Tipo: Text |
Palavras-chave: Polyurethane; Life time prediction; Hydrolysis; Offshore; Thermal insulation; Durability. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00174/28572/26957.pdf |
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| Tchalla, Siwavi Tatiana; Le Gac, Pierre-yves; Maurin, R.; Creac'Hcadec, R.. |
| Polychloroprene rubbers are widely used in marine structures and often filled with silica in order to increase mechanical properties. The presence of silica fillers leads to a complex degradation of the material. This study aims to understand the deeper degradation mechanisms involved when a silica filled polychloroprene is used in sea water. To do so, 4 polychloroprene rubbers filled with different amounts of silica (from 0 to 45 phr) were aged in natural sea water for 6 months at temperatures ranging from 25 to 60 °C. Moreover, a natural rubber with similar formulation was also considered in order to evaluate the role of the chlorine atom in the degradation. . The chemistry and mechanics of the rubber degradation were also studied. In the presence of... |
| Tipo: Text |
Palavras-chave: Polychloroprene; Seawater; Silica filler; Hydrolysis. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00376/48689/49020.pdf |
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| Derombise, Guillaume; Van Schoors, Laetitia Vouyovitch; Davies, Peter. |
| Technora fibres are high performance aramid fibres which have been used in ropes and protective clothing for many years. They are also now being proposed as geotextiles for soil reinforcement. However, there is a lack of experience on the long-term behaviour of Technora fibres in an alkaline environment (lime-treated ground.). Consequently, aging studies have been performed under different conditions (deionised water, pH9 and pH11). Hydrolytic degradation has been evaluated by FTIR, viscometry, TGA, density measurements, SEM, and by tensile measurements. Some chain degradation and finish rearrangements have been highlighted, but Technora fibres retain their mechanical properties for all the conditions considered here. |
| Tipo: Text |
Palavras-chave: Aramids; Fibres; Technora; Hydrolysis; Long-term behaviour. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00002/11289/8052.pdf |
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| Le Gac, Pierre Yves; Fayolle, Bruno. |
| This study deals with the durability of composites based on polyamide 6.6 (PA6.6) in a humid environment, and more especially, with the loss of fracture properties. It is known that PA6.6 undergoes plasticization in the presence of water, but hydrolysis also occurs. This hydrolysis leads to a sharp decline in fracture properties in resin. The aim of this study is thus to understand the behavior of two PA6.6-based composites, one containing short glass fibers and the other both glass fibers and a rubber. The results showed the transition from ductile to brittle behavior as a function of hydrolysis time in resin. For composites, the drop in elongation breaking with the macromolecular chain length was linear for all ageing conditions considered here without... |
| Tipo: Text |
Palavras-chave: Polyamide 6.6; Hydrolysis; Fracture; Embrittlement; Reinforced plastics. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56197/57755.pdf |
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| Le, Minh Chau. |
| Fish sauces are traditionally used in most Asian countries. Whatever the process, the principle is the same i.e. a fish autolysis in saline media followed by a fermentation step. Not less than 18 months are needed to obtain a brown liquid rich in salt and amino acids. This PhD work aims to determine if an addition of proteases can speed up the process while keeping the nutritional and sensorial properties. The first chapter presents the characteristics of fish sauces and the key parameters of the processes used. In the second chapter, several industrial proteases are compared each other for their capacity to liquefy the fishes in hyper saline conditions. Kinetics of proteolysis and biochemical characteristics of the resulting hydrolysates are established... |
| Tipo: Text |
Palavras-chave: Sauce de poisson; Hydrolyse; Enzyme; Protéase; Sardine; Anchois; Fish sauce; Hydrolysis; Enzyme; Protease; Sardine; Anchovy. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00259/36997/35488.pdf |
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| Bardin, Antoine; Le Gac, Pierre Yves; Cérantola, Stéphane; Simon, Gaelle; Bindi, Hervé; Fayolle, B.. |
| A hydrolytic kinetic model predicting chains scissions of a polyurethane elastomer (TPU) containing an anti-hydrolysis agent (stabilization via carbodiimide) was developed. This model is based on four components: uncatalysed hydrolysis, acid-catalysed hydrolysis, carboxylic acid dissociation and competitive carbodiimide-based deactivation of acid. Protons were considered as the key catalyst responsible for the hydrolysis. Model parameters were determined by fitting experimental data measured on unstabilized and stabilized TPUs, aged in immersion from 40 to 90 °C. Scission kinetics were predicted for immersion and 50% relative humidity conditions, from 10 to 100 °C. Structure-failure property relationships were also investigated, between molar mass and... |
| Tipo: Text |
Palavras-chave: Thermoplastic elastomer; Hydrolysis; Kinetic model; Structure-property relationships. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00588/70044/67978.pdf |
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| Registros recuperados: 43 | |
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