823 resultados para HYDROGEN STORAGE
Resumo:
Thermal energy storage (TES) can increase the thermal energy effieresa, of a process by reusing the waste heat from industrial process, solar energy or other sources. There are different ways to store thermal energy: by sensible heat, by latest heat, by sorption process or by chemical reaction. This thesrs provides a-state-of-the-art review of the experimental performance of TES systems based on solid gas sorption process and chemical reactions. The importance of theses processes is that provides a heat loss free storage system with a high energy density.
Resumo:
Els materials de canvi de fase (PCM) han estat considerats per a l’emmagatzematge tèrmic en edificis des de 1980. Amb la inclusió dels PCM en plaques de guix, guix, formigó o altres materials que s’utilitzen per a cobrir les parets, l’emmagatzematge tèrmic pot ser part de les estructures fins i tot en edificis lleugers. Les noves tècniques de microencapsulació han obert moltes possibilitats en aplicacions per a edificis. El treball que es presenta és el desenvolupament d’un formigó innovador mesclat amb PCM microencapsulat, amb un punt de fusió de 26 oC i una entalpia de canvi de fase de 110 kJ/kg. El primer experiment va ser la inclusió del PCM microencapsulat dins del formigó i la construcció d’una caseta amb aquest nou formigó-PCM. Es va construir una segona caseta al costat de la primera amb les mateixes característiques i orientació però amb formigó convencional que serveix com a referència. Durant els anys 2005 i 2006 es va analitzar el comportament d’ambdues casetes i més tard es va edificar un mur Trombe a la paret sud de totes dues per investigar la seva influència durant la tardor i l’hivern.
Resumo:
Orange fruits from two seasons, in April and August 2006 representing late 2005 and early 2006 harvests respectively were cured in hot air at 36-37(0)C to 1%, 3%, 5% and 7% weight loss before storage at 28(0)C and 86% relative humidity (RH). The fruits were observed for incidence of decay, further weight loss, juice content, firmness or softening of the peel, total soluble solids (TSS), pH, titratable acidity, and colour during storage. Curing reduced the incidence of decay. All control fruits were rotten by day 21 in August harvest while 22.5% of the control was rotten by day 56 in the April harvest. Storage life was extended beyond 56 days in fruits cured with 1, 3, 5 and 7% in April harvest as there was no decay throughout, while decay incidence in August harvest was 88.9, 61.1, 22.2 and 31.3% in 1, 3, 5 and 7% respectively. Penicillium digitatum, Phytophthora sp., Alternaria citri and Collectotrichum gloeosporioides were among decay causing moulds detected. Control fruits lost more weight during storage than cured fruits did. Fruit rind hardening was more noticed in the control and those cured to 1% weight loss, especially from the April harvest. It was insignificant in other treatments in both trials. Titratable acidity, pH, juice content and TSS were not affected by the treatment. Colour change to yellow was however retarded by curing. Curing to 5% weight loss was best for decay control and quality retention.
Resumo:
'Douradão' peach is a perishable product and when cold stored is subject to chilling injury. The objective of the experiment was to evaluate the effect of modified atmosphere packaging (MAP) and cold storage on quality and storage life of these peaches. Fruits were packed in polypropylene (PP) trays and placed inside low density polyethylene (LDPE) bags (30, 50, 60, 75 μm thickness) with active modified atmosphere (10 kPa CO2 + 1.5kPa O2, balance N2). The control was made with peaches held in nonwrapped PP trays. Fruits were kept at 1 ± 1 °C and 90 ± 5% relative humidity (RH) for 28 days and CO2 and O2 within packages was monitored every two days. After 14, 21 and 28 days, samples were withdrawn from MAP and kept in air at 25 ± 1 °C and 90 ± 5% RH for ripening. On the day of removal from the cold storage and after 4 days, peaches were evaluated for weight loss, decay incidence, flesh firmness, woolliness incidence, soluble solids content (SSC), titratable acidity (TA) and juice content. The results showed that MAP had influence on reducing weight loss and prevented postharvest decay. MAP of 1-2 kPa O2 and 3-6 kPa CO2 at 1 °C (from 50 and 60 μm LDPE films) were effective for keeping good quality of 'Douradão' peaches during 28 days of storage, the ripe fruits showed reduced incidence of woolliness, adequate juiciness and flesh firmness. Packages of 30 and 75 μm LDPE films were ineffective for reducing woolliness during cold storage. MAP fruits showed lower SSC and no relevant effect on TA. Control fruits did not present marketable conditions after 14 days of cold storage.
Resumo:
Oxidative stress is implicated in the pathogenesis of neurodegenerative disorders and hydrogen peroxide (H2O2) plays a central role in the stress. Huprines, a group of potent acetylcholinesterase inhibitors (AChEIs), have shown a broad cholinergic pharmacological profile. Recently, it has been observed that huprine X (HX) improves cognition in non transgenic middle aged mice and shows a neuroprotective activity (increased synaptophysin expression) in 3xTg-AD mice. Consequently, in the present experiments the potential neuroprotective effect of huprines (HX, HY, HZ) has been analyzed in two different in vitro conditions: undifferentiated and NGF-differentiated PC12 cells. Cells were subjected to oxidative insult (H2O2, 200 µM) and the protective effects of HX, HY and HZ (0.01 µM- 1 µM) were analyzed after a pre-incubation period of 24 and 48 hours. All huprines showed protective effects in both undifferentiated and NGF-differentiated cells, however only in differentiated cells the effect was dependent on cholinergic receptors as atropine (muscarinic antagonist, 0.1 µM) and mecamylamine (nicotinic antagonist, 100 µM) reverted the neuroprotection action of huprines. The decrease in SOD activity observed after oxidative insult was overcome in the presence of huprines and this effect was not mediated by muscarinic or nicotinic receptors. In conclusion, huprines displayed neuroprotective properties as previously observed in in vivo studies. In addition, these effects were mediated by cholinergic receptors only in differentiated cells. However, a non-cholinergic mechanism, probably through an increase in SOD activity, seems to be also involved in the neuroprotective effects of huprines.
Resumo:
Aquaporins are water channel proteins that mediate the fine-tuning of cell membrane water permeability during development or in response to environmental stresses. The present work focuses on the oxidative stress-induced redistribution of plasma membrane intrinsic protein (PIP) aquaporins from the plasma membrane (PM) to intracellular membranes. This process was investigated in the Arabidopsis root. Sucrose density gradient centrifugation showed that exposure of roots to 0.5 mM H2O2 induces significant depletion in PM fractions of several abundant PIP homologs after 15 min. Analyses by single-particle tracking and fluorescence correlative spectroscopy showed that, in the PM of epidermal cells, H2O2 treatment induces an increase in lateral motion and a reduction in the density of a fluorescently tagged form of the prototypal AtPIP2;1 isoform, respectively. Co-expression analyses of AtPIP2;1 with endomembrane markers revealed that H2O2 triggers AtPIP2;1 accumulation in the late endosomal compartments. Life-time analyses established that the high stability of PIPs was maintained under oxidative stress conditions, suggesting that H2O2 triggers a mechanism for intracellular sequestration of PM aquaporins without further degradation. In addition to information on cellular regulation of aquaporins, this study provides novel and complementary insights into the dynamic remodeling of plant internal membranes during oxidative stress responses.
Resumo:
L'hydrogène sulfuré (H2S) est un gaz toxique retrouvé à l'état naturel et dans certains milieux industriels, à l'origine d'intoxication accidentelle, mais pouvant être également et facilement synthétisé de manière domestique. Des cas de suicide par hydrogène sulfuré ont ainsi été décrits à partir de produits ménagers dans la littérature depuis 2009, aux États-Unis et au Japon. La plupart présentait des délais post mortem (DPM) courts (moins de 72 heures). En France, les intoxications aiguës à l'H2S demeurent rares et sont le plus souvent liées à des accidents du travail. Nous rapportons ici le cas d'un homme âgé de 37 ans découvert à son domicile, en état de décomposition avancée avec un DPM de deux mois. Compte tenu de la présence d'une importante signalétique avisant du danger potentiel d'exposition à l'H2S, des mesures de précaution ont été mises en oeuvre dès la découverte du corps et poursuivies jusqu'aux opérations d'autopsie. Les analyses toxicologiques ont confirmé la présence d'H2S au niveau des prélèvements de cerveau et de muscle. Le cas présenté constitue le premier cas de suicide avec un délai post mortem long à l'H2S rapporté en France. Dans la littérature, les constatations macroscopiques à l'autopsie ne sont pas spécifiques tandis que les analyses toxicologiques reposent essentiellement sur la recherche et la quantification d'H2S. En raison de leur redistribution post mortem, les résultats de ces analyses doivent être interprétés avec prudence, et encore plus en cas de délai post mortem long et de phénomènes de putréfaction qui peuvent également être une source de génération d'H2S post mortem. Hydrogen sulfide (H2S) which is a poisonous gas found either in the natural state or in industrial environments and potentially linked with accidental intoxication, can also be easily handmade. Several cases of suicide by inhaling H2S produced by mixing household products have been reported in the literature since 2009 in USA and Japan. Most of them involved short post mortem delays up to 72 hours. In France, acute H2S poisoning remains rare and mostly accidental. We report the case of a 37-year-old man found at home, in an advanced stage of decomposition with a 2-month post mortem delay. As numerous warning signs about a high risk of H2S exposure were present, some precautionary measures were taken from the discovery of the cadaver to the autopsy. Toxicological analyses confirmed the presence of H2S in brain and muscle samples. This observation is the first French case with a long post mortem delay. As macroscopic findings in such cases are described to be unspecific in literature, toxicological analysis must focus on the detection and the quantification of H2S. However, due to the phenomena of post mortem drug redistribution and neo-formation, their results should be interpreted with much more caution when the post mortem delay is long. The potential increase in such voluntary-intoxication-related-deaths in France, similar to the recent Japanese and American waves of suicides, requires for forensic scientists, a good knowledge of both thanatological and toxicological pictures, and precautionary measures to adopt in such situations.
Resumo:
BACKGROUND: Exercise prevents the adverse effects of a high-fructose diet through mechanisms that remain unknown. OBJECTIVE: We assessed the hypothesis that exercise prevents fructose-induced increases in very-low-density lipoprotein (VLDL) triglycerides by decreasing the fructose conversion into glucose and VLDL-triglyceride and fructose carbon storage into hepatic glycogen and lipids. DESIGN: Eight healthy men were studied on 3 occasions after 4 d consuming a weight-maintenance, high-fructose diet. On the fifth day, the men ingested an oral (13)C-labeled fructose load (0.75 g/kg), and their total fructose oxidation ((13)CO2 production), fructose storage (fructose ingestion minus (13)C-fructose oxidation), fructose conversion into blood (13)C glucose (gluconeogenesis from fructose), blood VLDL-(13)C palmitate (a marker of hepatic de novo lipogenesis), and lactate concentrations were monitored over 7 postprandial h. On one occasion, participants remained lying down throughout the experiment [fructose treatment alone with no exercise condition (NoEx)], and on the other 2 occasions, they performed a 60-min exercise either 75 min before fructose ingestion [exercise, then fructose condition (ExFru)] or 90 min after fructose ingestion [fructose, then exercise condition (FruEx)]. RESULTS: Fructose oxidation was significantly (P < 0.001) higher in the FruEx (80% ± 3% of ingested fructose) than in the ExFru (46% ± 1%) and NoEx (49% ± 1%). Consequently, fructose storage was lower in the FruEx than in the other 2 conditions (P < 0.001). Fructose conversion into blood (13)C glucose, VLDL-(13)C palmitate, and postprandial plasma lactate concentrations was not significantly different between conditions. CONCLUSIONS: Compared with sedentary conditions, exercise performed immediately after fructose ingestion increases fructose oxidation and decreases fructose storage. In contrast, exercise performed before fructose ingestion does not significantly alter fructose oxidation and storage. In both conditions, exercise did not abolish fructose conversion into glucose or its incorporation into VLDL triglycerides. This trial was registered at clinicaltrials.gov as NCT01866215.
Resumo:
The aim of this master´s thesis is to study which processes increase the auxiliary power consumption in carbon capture and storage processes and if it is possible to reduce the auxiliary power consumption with variable speed drives. Also the cost of carbon capture and storage is studied. Data about auxiliary power consumption in carbon capture is gathered from various studies and estimates made by various research centres. Based on these studies a view is presented how the power auxiliary power consumption is divided between different processes in carbon capture processes. In a literary study, the operation of three basic carbon capture systems is described. Also different methods to transport carbon dioxide and carbon dioxide storage options are described in this section. At the end of the thesis processes that consume most of the auxiliary power are defined and possibilities to reduce the auxiliary power consumption are evaluated. Cost of carbon capture, transport and storage are also evaluated at this point and in the case that the carbon capture and storage systems are fully deployed. According to the results, it can be estimated what are the processes are where variable speed drives can be used and what kind of cost and power consumption reduction could be achieved. Results also show how large a project carbon capture and storage is if it is fully deployed.
Resumo:
The present study reports details of the stoichiometric characterization of the mixed complex system, V(H2O2)PAR, formed when vanadium adequately reacts with hydrogen peroxide and with 4-(2-Pyridilazo)Resorcinol. Also the presence of polynuclear species was investigated in order to elucidate about unambiguous assignment of the molar absorptivity, stability constant and composition of the complex. Two mathematical treatments methods of the experimental results were employed. From the results it can be concluded that this system corresponds to a mononuclear complex with 1:1:1 stoichiometry.
Resumo:
The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts.
Resumo:
The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts.