舟山本岛及离岛土壤理化性质的研究

为了研究舟山本岛及离岛土壤的理化性质,本文以舟山本岛及离岛的工、农、生活区域的土壤为研究对象,以土壤容重、孔隙度、pH值、有机碳含量、石油类物质含量、含盐量、含水量、氯离子含量及养分元素(有效K、Ca、Mg、Cu、Fe、Zn、Mn)含量为测定指标。研究结果表明,舟山本岛及离岛试验点0～30 cm土层土壤均呈弱酸性;容重和孔隙度均在适宜范围内,土壤的透气性较好,且土壤中含水量丰富,达到适宜甚至偏湿水平;土壤中氯离子含量为38.1～171.6 mg/kg,高于全国平均水平(59.6 mg/kg),且土壤中的氯离子含量和含盐量随土层变化的趋势具有一致性,属于中轻度盐化土壤;土壤肥力较好,有机碳含量普遍达到了一级水平;土壤中有效Mn、Fe、Zn的含量处于中高水平,有效Cu含量处于中下水平,而有效Mg、Ca、K的含量处于较低水平;土壤中石油类物质含量为34.94～296.44 mg/kg,均在安全范围内,土壤并没有受到石油污染。     

机械化学法修复石油烃污染土壤及对土壤特性的影响

以典型石油烃正十六烷为特征污染物,采用批次实验研究机械化学处理对模拟石油烃污染土壤的修复效果及影响因素;采用GC/MS分析土壤中正十六烷的降解产物,通过XRD、FTIR、SEM和BET对处理前后土壤样品进行表征,并分析土壤有机碳含量的变化,揭示石油烃污染土壤的机械化学法修复机理。结果表明,在球磨机转速为500r/min,球料比为35∶1,大、中、小钢球配比为2∶5∶3,正十六烷投加量为2.5μL/g时,球磨4h后正十六烷降解率达95.86%。球磨处理过后土壤颗粒表面变粗糙,助磨效果较好的石英含量显著增多。与处理前相比,球磨处理后未检出短链烷烃,表明正十六烷降解较为彻底。土壤有机碳含量和吸附能力显著提高,使得残留低浓度石油烃难以全部去除。机械化学法修复石油烃污染土壤具有快速、高效、彻底等优势,具有良好的应用前景。     

溶剂萃取法修复石油污染土壤

对溶剂萃取法修复石油类污染土壤的新技术做了较为全面的概述.首先,介绍了溶剂萃取技术的概念、机理和适用范围;其次,介绍了包括有机溶剂、表面活性剂、环糊精、超临界流体在内的萃取剂的研究进展;再次,阐述了影响溶剂萃取效率的因素和溶剂萃取的工艺条件;最后,对溶剂萃取技术的研究和应用做了展望.     

徐州市城区表层土壤的理化性质研究

采用野外调查与室内分析相结合的方法,对徐州市城区表层土壤(0～10 cm)的理化性质进行研究。结果表明,城区土壤有酸化的趋势;土壤有机质及全量氮磷钾含量均低于该地区自然褐土;受人为作用方式与强度不同的影响,土壤有效氮磷钾含量表现出较大的差异性。     

石油污染土壤热脱附结焦机理及结焦特性综述

结焦问题一直是热脱附处理石油污染土壤亟待解决的问题,解决结焦问题能够提高热脱附设备的处理效率、降低处理成本以及延长设备使用寿命。总结了结焦机理的三种假设：相分离机理、自由基机理、碳正离子机理和金属催化机理。吸附结焦特性主要总结了工艺参数和原料性质两个方面对结焦的影响。工艺参数包括反应温度、油气停留时间和停留温度三个方面;原料性质包括原油性质、催化剂性质和反应物浓度三个方面。以期为热脱附结焦问题的研究提供思路。     

石油污染土壤的生物修复研究进展

综述治理石油污染土壤的生物修复技术研究进展。分析讨论了影响石油污染土壤的生物修复过程的主要因素,并总结了生物强化手段的未来发展方向。     

微波修复石油污染土壤的研究现状与展望

文章简要介绍了石油污染土壤的现状和危害、微波修复石油污染土壤技术的基本原理,对比了微波修复和传统修复技术的优缺点,探讨了近几年微波修复石油污染土壤技术的研究现状,并且对今后修复的发展方向进行了预测。     

热熔法处理石油污染土壤的研究

对热熔法处理辽河油田石油污染土壤的实验条件进行了探讨。其最佳实验条件为处理时间 30min、处理温度 80℃、液固比 3.0、搅拌速度 4 80r/min。处理后 ,粒径 >2 .5mm的土壤中石油烃含量已达到标准 ,而粒径 <2 .5mm的土壤石油烃含量仍然超标 ,还需后续处理。     

石油污染土壤的修复技术

我国油气田的开发、开采为国家带来了巨大的经济收益的同时也对油田及其产业链周边土壤造成污染,石油污染土壤会对其中种植作物的质量以及产量造成严重影响,甚至危害人类身体健康,对其修复已然成为社会的积极关注,相关领域的研究者也在不断探索石油污染土壤的修复。基于此,简要概述了石油污染土壤产生的原因及危害,并对多种修复技术：微生物修复、植物修复、土壤替换、物理修复、化学修复技术进行详细描述,就现有多种土壤修复技术进行探讨与展望,希望对今后该领域技术研发有所帮助。     

腐植酸物质对盐碱化中低产田土壤理化性质及玉米影响的研究

通过田间试验探讨了复合改良制剂、草炭、风化煤等腐植酸类物质施用对盐碱化中低产田土壤理化性质及生长作物的影响，结果表明：复合改良制剂、草炭、风化煤施用对土壤理化性质均有积极的影响，与对照相比达到显著水平。玉米产量的方差分析表明，复合改良制剂处理与草炭、风化煤等处理差异显著，与对照差异极显著，增产率均达到30．67％以上。     

Fatty acid composition and its relationship with physicochemical properties of pecan (Carya illinoensis) oil

The composition and physicochemical properties of pecan (Carya illinoensis) kernels and oils from different native trees of the central region of Mexico were investigated. The main compositional characteristic of the kernel was the high lipid content (70–79% w/w on dry basis) with elevated concentration of oleic acid (55–75% w/w). The results confirmed the relationship in the biosynthesis of linoleic and linolenic acids from oleic acid existing in oilseeds. Our results indicate that in pecans such relationship is a function of pecan tree age. The proportion of oleic, linoleic, and linolenic fatty acids determined the oxidative stability, viscosity, and melting/crystallization behavior of pecan oil. In general, these properties in pecan oils were similar or superior to extra-virgin olive oil and unrefined sesame oil. Although all native pecan oils studied showed a significant concentration of oleic acid, a particular group of native Mexican pecan trees produces an oil with a fatty acid composition with the nutritional appeal that consumers demand nowadays (i.e., very high oleic acid, 60–75%), with excellent natural oxidative stability (i.e., induction time for oxidation between 8.5 and 10.8 h), and substantially higher concentrations of α-, γ-, and δ-tocopherol than in pecan varieties previously reported in the literature.     

Manoeuvring the physicochemical and nutritional properties of vegetable oils through blending

Modification of vegetable oils is carried out to make them suitable according to their specific end use as most of the vegetable oils in original forms do not meet the recommended dietary allowance of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. Vegetable oils are modified using a variety of techniques including hydrogenation, interesterification, fractionation, and blending. However, blending is the most widely accepted method for improving the physicochemical properties, nutritive value and oxidative stability of vegetable oils because it is simple, cost-effective, non-destructive, and does not involve chemical treatments. Blending vegetable oils with contrasting fatty acid compositions or blending omega 3 fatty acids and antioxidants rich minor oils with major oils are two common strategies to formulate blends. Blended oil with balanced fatty acids could play substantial role in improving the consumers' health. However, while designing vegetable oil blends, it is important to keep in mind the intended application of the formulated blend, consumer's demands and also food laws. This review paper covers the literature related to blending of vegetable oils with a focus on effect of vegetable oils blending on their physicochemical and nutritional properties, health benefits and utility in food industries.     

Effects of repeated frying on physicochemical characteristics,oxidative stress,and free radical scavenging potential of canola oil and ghee

The repeated use of cooking oils and ghee for the deep frying of food materials may affect their nutritional quality. The present study evaluated the effect of repeated frying on the physicochemical characteristics and antiradical potential of canola oil and ghee. The oil and ghee were used for frying of fish and chicken for 2, 4, 6, 8, and 10 frying cycles followed by the analysis of physicochemical, oxidative stress, and antiradical parameters. Regression analysis of the data showed a frying cycle-dependent significant linear increase in saponification (R² = 0.9507–0.9748), peroxide and acid values (R² = 0.956–0.9915), and malondialdehyde (MDA) production (R² = 0.9058–0.9557) of canola oil and ghee subjected to fish and chicken frying but exponential increase in saponification value (R² = 0.9778) and MDA production (R² = 0.7407) of canola oil and ghee used for fish frying. The increase in the number of frying cycles linearly decreased the iodine value (R² = 0.9781–0.9924), and 1, 1-diphenyl-2-picrylhydrazyl, hydroxyl, and 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging potential (R² = 0.9089–0.9979) of canola oil and ghee. Repeated frying in cooking oil and ghee increases oxidative stress and decreases their physicochemical and antioxidant qualities. Canola oil was comparatively more oxidative resistant than canola ghee. The regression equations derived from regression analysis will guide researchers to conduct similar types of univariate studies.     

Physicochemical characteristics and thermal stability of Jordanian jojoba oil

Viscosity, flash point, refractive index, viscosity index, specific gravity, aniline point, foam testing, color stability, ash content, water content, saponification value, iodine value, and other properties were investigated for Jordanian jojoba oil. Results showed that jojoba oil has low ash and water contents and high flash point and viscosity index. Viscosity and specific gravity changed only slightly with temperatures. As an additive, jojoba oil improved the viscosity index of lubricants from 100 to 130. When subjected to heating and cooling from 40 to 200°C, the chemical structure, kinematic viscosity, and refractive index remained almost constant. Thus, jojoba oil was highly stable in this temperature range.     

柴油微乳液的制备及其性能研究

介绍了-10<'#>,0<'#>柴油微乳液的组成,确定了柴油、水、表面活性剂的质量配比,采用超声波处理为分散手段制备了微乳化柴油;并将-10<'#>柴油制备的微乳液与0<'#>柴油制备的微乳液作了对比;对制得的微乳化柴油的十六烷值、闪点、密度、黏度、粒径、凝点、热值、胶质质量浓度等理化性能指标进行了测定与分析对比;同时...     

Composition and physicochemical properties of corn wax

Corn wax, as a kind of vegetable wax, is a by-product of the corn oil industry. In this study, the corn wax was obtained from the corn oil refineries and purified by solvent defatting and bleaching. The composition and physicochemical properties of corn wax were studied to provide theoretical guidance for the production and application of corn wax. The results showed that the purity of corn wax was higher than 95%, and the corn wax ester ranged from C42 to C58, with C46, C44, and C48 being predominant. The carbon number of fatty acids was in the range of 16–30, with a higher proportion of C20, C22, and C24. The fatty alcohols varied from C20 to C32 and were dominated by C22, C24, C30, and C23. The physicochemical properties of corn wax were also determined and compared with other vegetable and animal waxes to get a more comprehensive understanding of corn wax. The results showed that the water content, iodine number, saponification number, and melting point of corn wax were 0.03 ± 0.01%, 6.77 ± 0.85 g/100 g, 74.31 ± 3.49 mg/g and 77.28 ± 7.89°C respectively. Corn wax was a green and healthy natural resource, which has great application potential in food, health care, and medicine.     

环丙基甲基酮连氮的制备及物化性质

以环丙基甲基酮和水合肼为原料,合成了一种新的酮连氮(环丙基甲基酮连氮).针对所得环丙基甲基酮连氮,在测定(计算)其物化性质(密度、黏度、熔点、比热容、表面张力、分子单点能等)的基础上,进一步测定了环丙基甲基酮+环丙基甲基酮连氮二元体系的气液相平衡(VLE),并应用NRTL模型对实验数据进行了关联.结果表明,在优化的反应...     

Influence of water content of the pulp on the extraction and the physicochemical properties of Canarium schweinfurthii oil

With the aim of contributing to the valorization of the Canarium schweinfurthii Engl. fruit pulp, through the extraction of its oil, we have studied the influence of the Canarium pulp's water content after drying at 45 °C on the yield of extraction using hexane. Furthermore we studied the physicochemical properties of the oil. It was observed that the oil's extraction yield is significantly influenced (p <0.01) by water content of the pulp. Maximum extraction yield (30.6 g fat/100 g) is obtained at a moisture content of 6.3%. The acid, saponification and peroxide values of the oils obtained were significantly influenced (p <0.05) by the humidity. The maximum acid values of 8.88 corresponded to a moisture content of 17.5%. Likewise, the saponification value showed a maximum of 154.1 for humidity content of 43.3% at the beginning of the drying step. The pulp oil's peroxide value initially at 3.7 meqO₂/kg increased progressively until attaining 51.0 O₂/kg at the end of drying. The iodine value was not influenced by humidity. A moisture content of 7.7% has been determined as the optimal value for optimizing both oil extraction yield and physicochemical property of the oil obtained.     

Effect of industrial microwave irradiation on the physicochemical properties and pyrolysis characteristics of lignite

The surface functional groups and pyrolysis characteristics of lignite irradiated by microwave were comparatively studied to evaluate the feasibility of using industrial 915 MHz for lignite drying. The drying kinetics, micro structure, chemical functional groups, re-adsorption properties, and pyrolysis characteristics of the dried coal were respectively analyzed. Results indicated that for typical Chinese lignite studied in this paper, 915 MHz microwave drying was 7.8 times faster than that of the hot air drying. After industrial microwave drying, the sample possessed much higher total specific surface area and specific pore volume than that of air dried sample. The oxygen functional groups and re-adsorption ratio of microwave irradiated coal decreased, showing weakened hydrophilicity. Moreover, during the pyrolysis of the coal dried by hot air and microwave, the yield of tar largely increased from 1.3% to 8.5% and the gas production increased correspondingly. The composition of the tar was also furtherly analyzed, results indicated that Miscellaneous hydrocarbons (HCs) were the main component of the tar, and microwave irradiation can reduce the fraction of polycyclic aromatic hydrocarbons (PAHs) from 26.4% to 22.7%.     

Changes in physicochemical properties and digestive characteristics of yam (Dioscorea opposita Thunb.) powder under different processing conditions using principal component analysis

Abstract

This study aimed to understand and establish changes in the physicochemical properties of yam powder with different processing methods, and select a suitable method for use in the development of hypoglycemic functional foods. Samples were dried using three methods, namely hot air drying, vacuum freeze drying, and microwave vacuum drying, and turned to powder using two smashing methods, namely ordinary smashing and superfine smashing (SS). Color changes, polarized light microscopy, differential scanning calorimetry, X-ray diffraction, polysaccharide dissolution rates, α-glucosidase inhibitory activities, glucose dialysis retardation indexes, and digestive characteristics were measured. The results showed that the drying method and the smashing method had significantly different effects on the physicochemical properties and digestion characteristics of the yam powder. Freeze-dried yam retained more nutrients, while SS increased the rapidly digestible starch content, reduced the digestible starch and resistant starch contents, and increased the polysaccharide dissolution rate in the yam powder samples. Six samples were compared using principal component analysis, with the highest composite score observed for the samples treated by freeze drying coupled with SS, followed by hot-air drying coupled with superfine smashing (HAO).