2,921 research outputs found

    Steam-Induced Coarsening of Single-Unit-Cell MFI Zeolite Nanosheets and Its Effect on External Surface BrĂžnsted Acid Catalysis.

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    Commonly used methods to assess crystallinity, micro-/mesoporosity, BrĂžnsted acid site density and distribution (in micro- vs. mesopores), and catalytic activity suggest nearly invariant structure and function for aluminosilicate zeolite MFI two-dimensional nanosheets before and after superheated steam treatment. Yet, pronounced reaction rate decrease for benzyl alcohol alkylation with mesitylene, a reaction that cannot take place in the zeolite micropores, is observed. Transmission electron microscopy images reveal pronounced changes in nanosheet thickness, aspect ratio and roughness indicating that nanosheet coarsening and the associated changes in the external (mesoporous) surface structure are responsible for the changes in the external surface catalytic activity. Superheated steam treatment of hierarchical zeolites can be used to alter nanosheet morphology and regulate external surface catalytic activity while preserving micro- and mesoporosity, and micropore reaction rates

    Biodiesel production from olive-pomace oil of steam-treated alperujo

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    Recently interest has been revived in the use of plant-derived waste oils as renewable replacements for fossil diesel fuel. Olive–pomace oil (OPO) extracted from alperujo (by-product of processed olives for olive oil extraction), and produced it in considerable quantities throughout the Mediterranean countries, can be used for biodiesel production. A steam treatment of alperujo is being implemented in OPO extraction industry. This steam treatment improves the solid–liquid separation by centrifugation and facilitates the drying for further extraction of OPO. It has been verified that the steam treatment of this by-product also increases the concentration of OPO in the resulting treated solid, a key factor from an economic point of view. In the present work, crude OPO from steam-treated alperujo was found to be good source for producing biodiesel. Oil enrichment, acidity, biodiesel yield and fatty acid methyl ester composition were evaluated and compared with the results of the untreated samples. Yields and some general physicochemical properties of the quality of biodiesel were also compared to those obtained with other oils commonly used in biodiesel production. As for biodiesel yield no differences were observed. A transesterification process which included two steps was used (acid esterification followed by alkali transesterification). The maximum biodiesel yield was obtained using molar ratio methanol/triglycerides 6:1 in presence of sodium hydroxide at a concentration of 1% (w/w), reaction temperature 60 °C and reaction time 80 min. Under these conditions the process gave yields of about 95%, of the same order as other feedstock using similar production conditions.Junta de Andalucía (P06-AGR- 01906)Dr. Guillermo Rodríguez is grateful to the JAE-Doc Programme (CSIC) co-funded by European Social Fund (Operational Programme ESF 2007-2013

    Hydrogen absorption in solid aluminum during high-temperature steam oxidation

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    Hydrogen is emitted by aluminum heated in a vacuum after high-temperature steam treatment. Wire samples are tested for this effect, showing dependence on surface area. Two different mechanisms of absorption are inferred, and reactions deduced

    The Effects of Seed Steam Treatment on Dry Bean Yield and Quality

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    Dry beans (Phaseolus vulgaris), a high-protein pulse crop, have been grown in the Northeast since the 1800’s. As the local food movement expands, consumers have requested stores stock more and more locally produced foods, and heirloom dry beans are no exception. Currently, the demand for heirloom dry beans has exceeded the supply. Farmers are interested in starting or scaling up dry bean production but require assistance in overcoming production barriers. Local farmers have struggled to obtain consistent high yields and quality. Growers’ lack of success with dry beans can be attributed to limitations in acquiring quality seed, poor stand establishment, diseases, and difficulty growing the crop to maturity by harvest. In an effort to improve seed quality, the University of Vermont Extension Northwest Crops and Soils Program collaborated with High Mowing Organic Seeds (Wolcott, Vermont), to evaluate the use aerated steam treatment on bean seed to reduce seedborne disease. A study to evaluate the impact of steam treated beans versus a non-treated control trial was initiated in June at Borderview Research farm, Alburgh, VT

    Interaction between dye and zinc in the dye-dispersing ZnO films prepared by a wet process

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    Dye-dispersing ZnO precursor gel films were prepared on indium tin oxide electrodes from a zinc acetate solution containing eosin Y by dip-coating, steam treatment, and then heating at a low temperature. The electronic interaction between the dye and zinc in the dye-dispersing gel films were investigated by spectroscopic and electrochemical measurements. A photocurrent was observed in the dye-dispersing gel electrodes before the steam treatment. The photocurrent value increased by the steam treatment and heating due to crystallization of the gel and removal of organic impurities. The dye molecules existed between the interlayers of the layered zinc hydroxide coexisting with the ZnO. The photoexcited electron in the dye should be injected into the ZnO conduction band via the layered zinc hydroxide. The value increased with an increase in the dye content even though the ZnO crystallinity decreased. The dye-zinc interaction, i.e., the complex formation and photoinduced electron injection, played an important role in the electron transport and photoelectric conversion.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 41(9):6559-6574 (2015)journal articl

    Microbial Activity of Soil Following Steam Treatment

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    The effect of steam treatment on subsurface aerobic and anaerobic microbial communities was investigated using multiple microbial assays. Soil samples were gathered and analyzed prior to, one month after, and eight months after a five-month field pilot test of steam injection and extraction. Aerobic soil samples were analyzed by respirometry, plate counts, and direct microscopic counts. Anaerobic microbial activity was examined by monitoring methane generation in anaerobic microcosms with gas chromatography. Respirometry showed pre-steam CO2 production was consistent with natural attenuation, post-steam (one month) CO2 production was below detection, and post-steam (eight months) CO2 production was about half of pre-steam. Post-steam (one and eight month) plate counts were one to four orders of magnitude lower than the pre-steam samples. Direct microscopic counts showed post-steam (one and eight month) cell numbers were higher than the pre-steam counts, but based on plate counts these cells were mostly non-viable. Significant amounts of methane and hydrogen were generated from pre-steam anaerobic microcosms, but post-steam microcosms had no detectable methane, and only trace amounts of hydrogen. Terminal restriction fragment (TRF) analysis was performed to determine the diversity of the microbial community before and after steam treatment. Pre-steam TRF analysis showed distinct differences in the microbial communities above and below the smear zone. Post-steam TRF analyses were not possible because insufficient DNA could be extracted from the soil

    A study on wear rates of 100Cr6 steel running against sintered steel surfaces under dry and starved lubrication

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    This paper investigates the tribological behavior of 100Cr6 steel pin running against sintered steel bearing material used in hermetic compressors. Tests were conducted under dry and starved lubrication sliding conditions in air at room temperature. Although porous structure acts as crack initiation sites thus limiting the wear resistance of sintered iron in dry sliding conditions under high contact stresses, it is believed to be beneficial in lubricated sliding conditions as it absorbs a large amount of lubricant. Wear tests without lubrication show that these pores are completely filled by abrasive particles in the initial stages of the test and no longer maintain their oil absorption capability. Initial results show that oxidation of frictional surfaces by flash temperature in dry conditions reduces weight loss volume by decreasing the coefficient of friction

    Improvement of seed quality of medicinal plants and herbs in organic farming

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    As in vegetable growing or grain cropping the seed quality is an important factor for the successful cultivation of medicinal plants and herbs. In spite of intensive efforts made by specialised seed producers there are recurring problems with important quality parameters (e.g. germination capacity, emergence or seed health). The lack of sufficient study results is typical for special purpose crops, also concerning the particular host-parasite relationship and its methodical verification. Few experiences with the improvement of seed quality of medicinal plants and herbs are available. The intention of the study is to test physical and biological methods of seed treat-ment for their practicability in medicinal plants and herb cultivation. Fundamental information on the pathogens is also examined. Moreover there is a focus on further aspects of the production techniques (e.g. harvesting time) as a means to improve the seed quality

    Surface decontamination of meat using thermal processes

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    The work presented here formed part of a European project entitled ‘BUGDEATH’ (EU QLK1-CT-2001-01415).End of project reportThis study investigated the effectiveness of a novel heat apparatus for decontamination of meat surfaces inoculated with important foodborne pathogens using either steam or dry air.European Unio

    Evaluation of non-chemical seed treatment methods for the control of Alternaria dauci and A. radicina on carrot seeds

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    The current study was initiated to evaluate the efficacy of physical methods (hot water, aerated steam, electron treatment) and agents of natural origin (resistance inducers, plant derived products, micro-organisms) as seed treatments of carrots for control of Alternaria dauci and A. radicina. Control of both Alternaria species by seed treatment with the resistance inducers was generally poor. Results were also not satisfactory with most of the formulated commercial micro-organism preparations. Based on the average of five field trials, one of these, BA 2552 (Pseudomonas chlororaphis), provided a low but significant increase in plant stand. Among the experimental micro-organisms, the best results were obtained with Pseudomonas sp. strain MF 416 and Clonostachys rosea strain IK726. A similar level of efficacy was provided by seed treatment with an emulsion (1%) of thyme oil in water. Good and consistent control was generally achieved with the physical methods aerated steam, hot water and electron treatment. Aerated steam treatment was, apart from the thiram-containing chemical standard, the best single treatment, and its performance may at least partially be due to extensive pre-testing, resulting in dosages optimally adapted to the respective seed lot. In some of the experiments the effect of the hot water treatment, which was tested at a fixed, not specifically adapted dosage, was significantly improved when combined with a Pseudomonas sp. MF 416 or C. rosea IK726 treatment. The results are discussed in relation to the outcome of experiments in which the same seed treatment methods and agents were tested in other seed-borne vegetable pathosystems
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