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This study experimentally quantified the formation of organic sulfur compounds in a commercial SuperBatch kraft pulping process using a laboratory pilot-scale digester. The results indicate that wood chips not only can adsorb HS- but also methyl mercaptan (MM) in the black liquor used for pretreatment during the two pretreatment stages. The absorption rate of MM is much faster than that of HS-. In the third stage of SuperBatch pulping, the rate of formation of MM and dimethyl sulfide (DMS) is very similar to that found in conventional batch kraft pulping processes. The study examined the applicability of the phase transition cooking (PTC) concept for reducing organic sulfur compounds in pulping, previously developed in laboratory batch pulping using a bomb-type digester, in a SuperBatch process. It was confirmed that there is a phase transition point (PTP) corresponding to PTC in SuperBatch pulping beyond which further delignification significantly increases the formation of volatile organic sulfur compounds. The results indicate that a 40% reduction of TRS formation can be achieved by using PTC. 相似文献
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探讨了在设计饮料生产线的过程中,设备耗用蒸汽所产生的冷凝水的回收与应用设计的思路。结合实际案例,分析了冷凝水回收系统的运行成本和回报成本。 相似文献
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The catalytic inactivation of Escherichia coli in water by a cerium (Ce)-promoted silver-loaded aluminum phosphate (Ag/ AlPO4) catalyst using molecular oxygen was investigated. With optimum Ce content, the Ag(Ce)/AlPO4 catalyst exhibited strong bactericidal activity. The process of decomposition of the cell wall and cell membrane was directly observed by TEM. The different morphological changes of E. coli cells treated with the Ag(Ce)/AlPO4 catalyst and those treated with Ag+ suggested that the Ag+ eluted from the catalyst surface did not play an important role during the bactericidal process. Results of DMPO spin-trapping measurements by electron spin resonance (ESR) indicated the formation of the reactive oxygen species (ROS) *OH and *O2-, which caused the considerable bactericidal activity. The formation of H2O2 acted as an important intermediate; this was confirmed by addition of catalase as the scavenger. A possible catalytic oxidation bactericidal mechanism using molecular oxygen was proposed for the Ag(Ce)/AlPO4 catalyst. 相似文献
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为进一步提升蚕丝织物的染色深度,利用活性红3BS在乙醇/水体系中对经阳离子表面活性剂改性的蚕丝织物进行染色,分析了染色温度、pH值、染料用量和染色时间对改性蚕丝织物性能的影响,同时也探究了改性蚕丝织物在乙醇/水体系中的动力学和热力学机制。试验结果表明:染色温度是影响改性蚕丝织物K/S值、明暗值、红绿值、黄蓝值和总色差值最大的因素,且随着染色温度的升高,染色速率常数先增大后降低,饱和吸附量逐渐增大,而半染时间、染料分配系数和标准亲和力逐渐减小;改性蚕丝织物的染色焓为-28.693 kJ/mol,染色熵为-0.066 kJ/(℃·mol), 改性蚕丝织物在乙醇/水中的染色过程为放热反应;改性后的蚕丝织物染色深度有所提升,各项染色牢度基本未发生变化。 相似文献
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Effect of different air/steam convection cooking methods on turkey breast meat: physical characterization, water status and sensory properties 总被引:1,自引:0,他引:1
Turkey breast samples were cooked using a forced convection oven at three relative humidity levels (RH=8, 35 and 88%) at 100°C. Cooking parameters (temperature, cook value, and yield), textural and sensory properties as well as water status of the samples were evaluated. The application of different RH levels resulted in different cooking performances and cooked meat quality. Low steam cooking conditions (RH=35%) significantly increased cooking yield (7% higher than the high steam cooking), moisture content and water-holding capacity and had a positive effect on perceived tenderness, as shown by sensory analysis, where steam cooked samples were perceived as the most tender. The more mobile protons of (1)H T(2) (relaxing at times longer than 1s) in low steam samples were related to the higher perceived tenderness. Low steam cooking allowed for less water consumption, making this process an attractive cooking method as compared to high steam, as it also resulted in higher quality cooked turkey meat. 相似文献
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1.6 水体污染控制,污水处理场设计 综上所述,本项目现代化KP浆厂工艺技术设备先进,黑液提取率98%-99%,碱回收率95%,在正常生产、流失很少的情况下,异常事故排放对水体的污染更为突出。因此,本项目注意在各生产车间设置足够贮槽,并使无害、轻、重污染水分流,便于生产管理,使非常事故排放导致的污染减至最少。 本项目设置污水处理场,主要是兼顾老系统的重污水3.5万m3/d(这些重污水过去是直接排放,严重污染沙溪河,曾使青山纸业成为福建省三个“污染大户”之一)。它是国内造纸行业最大的活性污泥法污水处… 相似文献
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Two-dimensional small-scale variability of pore water phosphate in freshwater lakes: results from a novel dialysis sampler 总被引:1,自引:0,他引:1
Vertical concentration profiles of soluble reactive phosphorus (SRP) in the upper sedimentary zone of freshwater lakes are an important means for studying internal phosphorus (P) loading and to gain insight into early diagenetic processes. The interpretation of such pore water profiles generally neglects the occurrence of horizontal variability at a specific sampling site. To further examine this variability, we have designed a novel two-dimensional sampler (2D peeper) consisting of 2280 chambers at a spatial resolution of 9 mm providing a sampling area of 43 x 44 cm. This new device was deployed in three eutrophic lakes in north-eastern Germany. The resulting 2D images of the SRP concentrations, diffusive fluxes, and turnover rates revealed systematic vertical and horizontal structures with local niches of increased phosphorus release. Thus, the extrapolation of P flux calculations based on one-dimensional pore water profiles may lead to a considerable error. The observed small-scale horizontal heterogeneity, probably mainly caused by organisms, was larger in the biologically more active Lake Müllrose and Süsser See than in the deeper Arendsee where meio- and macrozoobenthos were missing. In all cases, the variability was highest at the sediment-water interface and diminished with sediment depth. 相似文献
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The reduction in pH was higher in aqueous solutions than in ethanolic solutions. Moreover, pH was lower in glycine compared
to diglycine and triglycine in both aqueous and ethanolic solutions. Maillard reaction products (MRPs) derived from diglycine
had a greater absorbance at 294 and 420 nm in ethanolic solution than an aqueous solution. The loss of glucose was higher
in ethanolic MRPs solution than in aqueous solutions. The glycine oligomer content in ethanolic solutions remained much higher
than that in aqueous solutions. Absorption in the ultraviolet (UV)-vis spectra was higher in MRPs derived from the ethanolic
solution than in those derived from the aqueous solution. The molecular weights of MRPs derived from an ethanolic solution
showed higher peak intensities than those derived from an aqueous solution, whereas the major peaks of the molecular weight
in an ethanolic solution were slightly different from those in an aqueous solution. 相似文献
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Madureira FD da Silva Oliveira FA de Souza WR Pontelo AP de Oliveira ML Silva G 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2012,29(4):665-678
A method using QuEChERS extraction and LC-MS/MS in electrospray positive ionisation mode was developed and validated for the analysis of 90 pesticides in a high water content matrix (tomato) in a single chromatographic run. To assess the intra-laboratory reproducibility of the method, validation was conducted on four different days by two different analysts. The validation data was treated using a spreadsheet developed in-house, which sets the most appropriate model for linear fit by determining whether the residuals of the calibration curves are homocedastic or heterocedastic. A statistical test for the significance of regression was also carried out. Calibration was always matrix-matched and the curves were obtained over the range 0.0075-0.10 or 0.020-0.125 mg kg(-1). Identification of analytes was based on retention times and MRM ratios. Recoveries were assessed at four different levels for each analyte and were between 73 and 106%, with relative standard deviations under reproducibility conditions of <20%. The measurement uncertainties of the method for each pesticide analysed were below 50%. Previous validation of the same method, applied to papaya samples and satisfactory results obtained in various proficiency tests with different high water content matrices, demonstrated the applicability of the method to these classes of commodities, without clean-up. The validated method will be applied routinely in the pesticide residues monitoring programme that constitutes the National Residue and Contaminant Control Plan of Brazil. 相似文献
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Abu Falah Gholami Hamed Saman Muhamad Zameri Mat Zakuan Norhayati Sharif Safian Streimikiene Dalia 《Holz als Roh- und Werkstoff》2021,79(4):753-772
European Journal of Wood and Wood Products - As wood and furniture industries have little knowledge of the implementation of lean manufacturing particularly in emerging economies, the purpose of... 相似文献
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试验以红粒小麦全麦粉为材料,采用单因素试验与三元二次正交试验,研究其粗类黄酮的水浴醇提工艺及体外清除DPPH·和·OH的能力。结果表明,乙醇浓度、料液比、浸提温度及浸提时间对粗类黄酮得率的影响均符合开口向下的抛物线模型。确定乙醇体积分数为95%,关键参数料液比(X_1)、浸提温度(X_2)、浸提时间(X_3)对粗类黄酮得率的影响符合三元二次回归模型;主效应:X_1X_2X_3;交互效应:X_1X_3X_1X_2X_2X_3;最优工艺参数:料液比1:19,66℃浸提107 min,类黄酮得率46.02 mg/g。红粒小麦粗类黄酮对DPPH·的清除率明显大于对·OH的清除率,且随浓度提高,清除率显著提高。研究为红粒小麦深加工提供参考。 相似文献
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An analytical system to quantify agaritine present in Agaricus blazei,Agaricus bisporus, and other food mushrooms was established using high pressure liquid chromatography combined with mass-spectroscopy (HPLC–MS). Water extracts from dried, homogenised mushrooms were kept at differing temperatures for defined periods to investigate the heat-stability of agaritine. Homogenates were then freeze-dried, and agaritine was extracted using methanol. After evaporation of methanol, agaritine levels were analysed by HPLC–MS. A. bisporus contained 341 ± 32 μg/g agaritine, and A. blazei contained 22–57 μg/g agaritine. While pure agaritine in H2O solution was heat-unstable and decomposed exponentially at 120 °C, agaritine in Agaricus water extracts was partially heat stable, and 20–50% of agaritine remained after 120 min at 120 °C. Thus agaritine, a known carcinogen, is likely to be present in Agaricus extracts sold as nutritional supplements. Therefore, a method was developed that can be used to remove agaritine from water extracts in order to prevent health risk. Agaritine was successfully removed from Agaricus water extracts by ethanol fractionation. 相似文献
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Influence of ethanol/water ratio in ultrasound and high‐pressure/high‐temperature phenolic compound extraction from agri‐food waste
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Marco Paini Alessandro A. Casazza Bahar Aliakbarian Patrizia Perego Arianna Binello Giancarlo Cravotto 《International Journal of Food Science & Technology》2016,51(2):349-358
The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions. 相似文献
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Heidemarie Sommer Michael Blankart Gerhard Eisenbrand 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,189(2):144-146
Summary Results of collaborative studies on methods for determination ofN-Nitrosodiethanolamine (NDELA), in cosmetics and in alkanolamines are reported. Participants from eleven laboratories in each study examined two freshly prepared model cosmetics, one emulsion and one shower gel and also one sample of triethanolamine. Samples were analyzed unspiked and after fortification with 50 g/kg NDELA. Distribution of unspiked and spiked samples and amounts of NDELA added were not known to the participants. In spiked samples overall mean values (±standard deviation) found for NDELA were 50 ± 9 gg/kg for the emulsion, 53 ± 8 gg/kg for the shower gel and 47 ± 10 g/kg for triethanolamine. With few exceptions, NDELA was not found in unspiked samples at concentrations exceeding the determination limit (10 gg/kg).
Ergebnisse von Ringversuchen zur Bestimmung vonN-Nitrosodiethanolamin in Cosmetica und in Alkanolaminen
Zusammenfassung Ergebnisse von Ringversuchen zur Bestimmung vonN-Nitrosodiethanolamin (NDELA) in kosmetischen Mitteln and in Alkanolaminen werden beschrieben. Teilnehmer aus jeweils elf Laboratorien analysierten zwei kosmetische Mittel, die für diese Studie frisch hergestellt wurden, eine Emulsion und ein Duschbad Bowie eine Probe Triethanolamin. Die Proben wurden undotiert Bowie nach Zusatz von jeweils 50 g/kg NDELA untersucht, wobei die Verteilung und Höhe der Dotierung den Teilnehmern nicht bekannt wares. Die Gesamtmittelwerte betrugen für die dotierte Emulsion 50 g/kg NDELA±9 g/kg SD (Standardabweichung), für das dotierte Duschbad 53 g/kg NDELA±8 g/kg SD and fur das dotierte Triethanolamin 47 g/kg NDELA ± 10 g/kg SD. Mit wenigen Ausnahmen wurden in den undotierten Proben keine NDELA-Gehalte gefunden, die die Bestimmungsgrenze von 10 g/kg überschritten.相似文献