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11.
The effect of temperature used for drying apple pomace on apple pectin characteristics, including chemical composition, color and gelpoint temperature (Tg) was determined. Pomace was obtained from commercial Granny Smith apples and dried in a rotary drier at different air temperatures (Tdr = 60, 70, 80 and 105 °C). Pectin was extracted from dried pomace in nitric acid solution (pH = 2.5) at 80 °C. Major minerals in apple pectin were Ca>Na>Mg. Galacturonic acid content (% AGA=60.6±1.8) was practically unaffected by drying temperature. Conversely, Tdr affected both the degree of methoxylation (DM) and the molecular weight (Mw) of extracted pectin. Mw was estimated by applying the Mark Houwink - Sakurada equation, through determination of intrinsic viscosity of pectin solutions. Mw reduced withTdr from approximately 122,000 (60°C) to 57,000 (105°C). Pectin color, as Hunter ΔE, was also affected by Tdr. A lighter color was obtained at 80°C. The higher gelpoint value (Tg= 80°C) was obtained with pectin from pomace dried at 80°C. Gelpoint was shown to be more sensitive to Tdr than other quality parameters: while DM had the same value both at 80 and 105°C, minimumTg occurred at the higher temperature. Tg was also very sensitive to pH. 相似文献
12.
Removal of formaldehyde from aqueous solutions via oxygen reduction using a reticulated vitreous carbon cathode cell 总被引:2,自引:0,他引:2
The removal of formaldehyde from waste streams to <0.3 ppm has been demonstrated using a cell with a reticulated vitreous carbon cathode; the formaldehyde is oxidized by hydrogen peroxide, formed at the cathode by reduction of oxygen. In most electrolytes studied (e.g. NaOH, NaCl and Na2SO4), the formaldehyde is oxidised only to formic acid. On the other hand, the addition of a low concentration of an iron salt (i.e. 0.5 mm), catalyses the complete oxidation to carbon dioxide. The removal of formaldehyde can be achieved in media of low ionic strength (< 10 mm) although the use of iron salts necessitates the adjustment of pH to 3 to maintain the catalyst in solution. 相似文献
13.
Ali M. El‐Halwagi Camilo Rosas José María Ponce‐Ortega Arturo Jiménez‐Gutiérrez Mahboobul S. Mannan Mahmoud M. El‐Halwagi 《American Institute of Chemical Engineers》2013,59(7):2427-2434
A new approach for the incorporation of safety criteria into the selection, location, and sizing of a biorefinery is introduced. In addition to the techno‐economic factors, risk metrics are used in the decision‐making process by considering the cumulative risk associated with key stages of the life cycle of a biorefinery that includes biomass storage and transportation, process conversion into biofuels or bioproducts, and product storage. The fixed cost of the process along with the operating costs for transportation and processing as well as the value of the product are included. An optimization formulation is developed based on a superstructure that embeds potential supply chains of interest. The optimization program establishes the tradeoffs between cost and safety issues in the form of Pareto curves. A case study on bio‐hydrogen production is solved to illustrate the merits of the proposed approach. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2427–2434, 2013 相似文献
14.
Zincating is used as a pre-treatment for aluminium prior to electroless nickel deposition during preparation of magnetic computer memory discs. Four immersion zincating solutions were evaluated at 22°C using single step or double zincating followed by electroless nickel deposition from a high phosphorus hypophosphite bath at 90°C. The coating process was monitored by potential vs. time curves obtained under open-circuit conditions during zincating then electroless nickel plating. The surface morphology of the aluminium, at various stages, was imaged by scanning electron microscopy and atomic force microscopy. Zero resistance ammetry was used to record galvanic currents between the aluminium and an inert platinum counter electrode during zincating. This, together with potential-time measurements, provided simple and valuable methods for following the zincating process and subsequent electroless Ni plating. Double zincating enabled a shorter induction time for electroless Ni deposition and resulted in a more complete coverage of the surface by Zn. 相似文献
15.
Nader Tehrani Dan Gallagher Monica Ponce de Leon Harry Lowd Richard Lee Lisa Huang Remon Alberts Janghwan Cheon Jumanah Jamal Aishah Al Sager 《世界建筑导报》2018,(2)
正Banq餐厅位是一家新型餐厅,位于便士储蓄银行(Penny Savings Bank)旧大楼以前用来经营银行业务的大厅内。餐厅分成两个部分,前面区域面向华盛顿大街,设计成酒吧,后面的大厅则作为用餐区。然而,这个空间在z轴上以天花板和地面之间的另一个分区为中心进行设计。如果由于餐厅空间活动的多变性而需要保持灵活性——包括两个座位、四个座位和六个座位,以及与聚会和其他活动有关的座位 相似文献
16.
A linear array of closely spaced AlGaAs lasers is mounted on an Si heat sink. Schottky diode detectors formed on the same Si chip provide optical sensing and electrical feedback signals for output power stabilization of the individual laser elements. The performance of a typical pair of adjacent devices is tested showing that electrical and optical crosstalk between lasers is virtually eliminated. 相似文献
17.
Giovanni Egidio Pazienza Xavier Ponce‐García Marco Balsi Xavier Vilasís‐Cardona 《International Journal of Circuit Theory and Applications》2007,35(4):449-462
Cellular neural networks (CNNs) are well suited for image processing due to the possibility of a parallel computation. In this paper, we present two algorithms for tracking and obstacle avoidance using CNNs. Furthermore, we show the implementation of an autonomous robot guided using only real‐time visual feedback; the image processing is performed entirely by a CNN system embedded in a digital signal processor (DSP). We successfully tested the two algorithms on this robot. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
18.
19.
R. Chaiyont C. Badoe C. Ponce de León J. L. Nava F. J. Recio I. Sirés P. Herrasti F. C. Walsh 《化学工程与技术》2013,36(1):123-129
A film of iridium and tin dioxides doped with antimony oxide (IrO2‐SnO2‐Sb2O5) was deposited onto Ti mesh and plate substrates by the Pechini method. The electrode surface morphology and composition were characterized by SEM‐EDS. The ternary oxide coating was used for the anodic oxidation of methyl orange (MO) azo dye. Linear sweep voltammetry was used to identify the electrode potentials that favour MO degradation. Batch electrolyses were then carried out at a constant electrode potential of 1.5, 1.75 and 2.0 V vs. SHE using either a three‐electrode batch cell or a flow reactor. The dye solutions were totally decolorized via reactive oxygen species, such as ?OH, H2O2 and O3 formed in situ from water oxidation at the Ti/IrO2‐SnO2‐Sb2O5 surface. 相似文献
20.
A techno‐economic analysis for the separation process in bioethanol production is presented. Optimized azeotropic separation processes in conjunction with process integration (mass and energy) are considered to simultaneously enhance the results from economic and environmental points of view. Process integration improves significantly the separation process because it helps to reduce the overall energy required in the reboilers based on energy integration and additionally to diminish the amount of required solvent based on mass integration. The SYNHEAT optimization model was applied for energy integration whereas a direct recycle strategy was implemented for the mass integration process. The best separation processes obtained correspond to an integrated conventional separation sequence with energy integration to ethanol‐water mixture III and integrated optional separation sequences with energy integration to ethanol‐water mixture III, with significant savings in utility costs and possible recycling of nearly all solvent. 相似文献