冷轧轧制油特性的探讨

本文介绍了窄带钢冷轧机组在现场生产中,使用乳化状轧制油遇到的一些情况,同时讨论了冷轧轧制油的几个工艺特性及理化指标。     

规划水资源论证技术要求探讨——以深圳石岩总部经济园区规划为例

2010年,水利部启动了规划水资源论证的试点工作并出台了试行技术要求。规划水资源论证把水资源管理的源头从建设项目向前推进至规划阶段,体现了"从源头和过程控制"的理念。以深圳石岩总部经济园区改造专项规划水资源论证为例,对园区规划水资源论证的内容、方法和要求进行了实例探讨,为规划水资源论证的编制提供参考。     

Physical Properties of Vegetable Oil and Chlorinated Ethene Mixtures

Laboratory experiments were conducted to investigate the abiotic interactions of soybean oil (SoyOil) and chlorinated ethene (CE) nonaqueous phase liquids (NAPLs). The mixed NAPL density and interfacial tension behaved ideally, as predicted by the volume ratio. The mixed NAPL viscosity increased exponentially from that of the pure CE to that of pure SoyOil as the volume fraction increased. The measured contact angle was highly variable and was unpredictable as a function of the volume composition of the mixed NAPL. The physical property effects indicate that the mobilization of residual CE NAPLs because of SoyOil injection is unlikely. Equilibrium dissolution of CEs from the NAPL mixtures behaved linearly as a function of the mole fraction. Dissolved SoyOil in simulated groundwater enhanced the dissolution of trichloroethene (TCE) during flow tests, increasing the effluent TCE concentration from 141?to?202?mg/L. The ready intermingling of the CE dense nonaqueous phase liquids (DNAPLs) and SoyOil indicate that such interactions may be significant at sites where vegetable oil is injected into DNAPL source areas to enhance in situ anaerobic bioremediation.     

雾状油膜水滴冷却润滑车削试验研究

油膜水滴是使用冷空气、微量可自然降解油剂和少量水,经复合喷雾法形成可自然分解的、新型绿色切削液.与传统切削液相比,油膜水滴在保护环境,节省资源等方面有很大的优势.通过车削试验,比较和分析不同冷却润滑条件下刀具磨损和已加工表面质量,揭示出雾状油膜水滴绿色切削液的优越性.     

Antifungal activity of five different essential oils in vapour phase for the control of Colletotrichum gloeosporioides and Lasiodiplodia theobromae in vitro and on mango

Mango fruit has high commercial value; however, major postharvest losses are encountered throughout the supply chain due to postharvest diseases. These results lead to the search for natural fungicide for postharvest diseases control. The antifungal effects of five essential oils (thyme, clove, cinnamon, anise and vitex) were assessed by disc volatilisation method. Thyme oil vapours at 5 μL per Petriplate, and clove and cinnamon oil at 8 μL per Petriplate showed 100% growth inhibition of mango pathogens in vitro. GC/MS analysis of essential oil showed thymol (23.88), o‐cymol (23.88) and terpinolene (23.88) as the major constituents of thyme oil. Clove and cinnamon oils contain 3‐allyl‐2‐methoxyphenol (37.42%) and benzofuran 3‐methyl (17.97%), respectively. Thyme oil as a fumigant at 66.7 μL L^?1 showed a significant (P < 0.05) inhibition on postharvest pathogens of mango fruits stored at 25 °C for 6 days. Results of our study suggest the possibility of using thyme oil as an alternate natural fungicide to manage postharvest diseases in mango.     

Process simulation using the expanded fluid model for viscosity calculations

The expanded fluid (EF) viscosity model was implemented and further developed for efficient integration into a commercial process simulator (VMGSim™). The model has three adjustable parameters per component and its inputs are density, pressure and low pressure gas viscosity. The model was adapted to use densities determined by the Rackett correlation (liquid phase) and the Advanced Peng–Robinson Equation of State (vapor phase). The enhanced EF model fit experimental viscosities of pure hydrocarbons, water and polar compounds important for the simulation of oil and natural gas systems with average absolute errors just above 5%. The implemented EF model was tested against experimental viscosity data that included hydrocarbon and aqueous mixtures with average absolutes errors of 0.7 and 6.2% respectively. Generalized expressions for the estimation interaction parameters of binary mixtures involving paraffins, naphthenes, aromatics, alcohols, glycols and water were obtained. The EF model was also applied to crude oil (bitumen) examples. The three key developments for the efficient implementation of the EF model in a commercial simulator were: (1) the appropriate selection of phase density models; (2) the automatic determination of model fluid specific parameters; and (3) the use of generalized mixing rules for the calculation of binary interaction parameters.     

Ozonated Mineral Oil: Preparation,Characterization and Evaluation of the Microbicidal Activity

The ozonation of vegetable oils has been studied, since the produced ointments have antibacterial and fungicidal activities. However, the ozonation of mineral oils has not been reported in the literature yet, opening an interesting field for examination. In this work, we have shown the ozonation of a commercial mineral oil (Nujol). The main goal was to produce oils containing free ozone, so that this gas could act as antimicrobial agent. It was found that in Nujol, ozone remains for at least 40 days and in the sample ozonized for 15 h its concentration was 7.5 mg mL^?1. Neat Nujol showed no antimicrobial activity against the tested microorganisms, however, when ozonated it showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Escherichia coli.     

Enzymatic transesterification for production of biodiesel using yeast lipases: An overview

Biodiesel has provided an eco-friendly solution to fuel crisis, as it is renewable, biodegradable and a non-toxic fuel that can be easily produced through enzymatic transesterification of vegetable oils and animal fats. Enzymatic production of biodiesel has many advantages over the conventional methods as high yields can be obtained at low reaction temperatures with easy recovery of glycerol. Microbial lipases are powerful biocatalysts for industrial applications including biodiesel production at lower costs due to its potential in hydrolyzing waste industrial materials. Among them, lipases from yeasts, Candida antarctica, Candida rugosa, Cryptococcus sp., Trichosporon asahii and Yarrowia lipolytica are known to catalyze such reactions. Moreover, stepwise addition of methanol in a three step, two step and single step reactions have been developed using yeast lipases to minimize the inhibitory effects of methanol. The latest trend in biodiesel production is the use of whole-cell as biocatalysts, since the process requires no downstream processing of the enzyme. Synthesis of value added products from the byproduct glycerol further reduces the production cost of biodiesel. This review aims at compiling the information on various yeast lipase catalyzed transesterification reactions for greener production of biodiesel.     

Coke Formation from Aircraft Engine Oils: Part II—Effects of Oil Formulation and Surface Composition

This is the second of two papers giving the results of a study undertaken to determine how aircraft engine oil degrades to form coke on oil-wetted surfaces. In part 2 the authors address the impacts of additives (which is related to oil types) and surface materials upon the oil coking process.

In Part 1 of this study, the authors showed that simple laboratory tests involving thin films of oil heated for specified timesltemperatures in open glass vials produced polymer and coke similar to the deposits seen on failed face seals taken from the operating aircraft engines and polymers isolated from used engine oils. Antioxidants inhibit and delay the coke producing reactions. After the antioxidant package is depleted to approximately 10 percent of the original level, the ester basestock undergoes accelerated oxidation to form oil-soluble polymers. As the oil spends additional time at elevated temperature, these polymers increase in molecular weight and undergo minor compositional changes becoming insoluble in the oil, producing deposits. If the time that a thin oil layer spends on a hot surface at elevated temperature can be limited so that the antioxidant does not deplete completely, coking can be prevented. This shifts the focus from coke minimization to coke prevention.

The authors results in Part 2 indicate that oil choice—which is largely a choice of antioxidant package—makes a large difference in how long oil can remain on a hot surface without forming polymer/coke deposits. For the oils studied in Part 2, the capabilities of the oils' antioxidant packages to inhibit coke formation varied 15 fold.

Surface material choice has minimal effect upon the rate of antioxidant depletion. However, once the antioxidant in the oil in a thin layer has become ineffective in inhibiting accelerated oxidation (approximately 10 percent of original concentration), the material the oil resides upon strongly effects the rate of the polymer/coke formation processes. Stainless steel speeds the process compared to a glass substrate.     

Estimation of Electric Transformer Service Life from Oil Degradation Kinetics

Petroleum-based transformer oil performs the dual roles of insulator and electrolyte depending on charges in the oil. The availability of charges for conduction influences the level of voltage breakdown in the mineral oil and depends on the intensity of physicochemical processes such as redox action, hydrolysis, photodegradation, sludge/particle development, and gas formation arising from thermal, mechanical, chemical, and electrical stresses in the oil. Previous investigators have focused mostly on single oil aging indicators to build models for estimation of the aging rates of transformer oils, within a time frame that is too short relative to the operational service life of transformers. In this research, the interdependence of oil voltage breakdown and changes in oil physicochemical characteristics was investigated experimentally using T24 and T14 oils. Tests were performed with a DTS-100D oil tester for voltage breakdown and a HKV 4000 series high kinematic viscosity bath. The calculated activation energies are 26.2?KJm?3 for T24 and 25.4?KJm?3 for T24 transformer oils, respectively. Neglecting catastrophic failure from environmental hazards, the estimated service lives of T14 and T24 transformers that are herein analyzed are 40 and 43 years, respectively. Their degradation constants were experimentally determined to be 7.38×10?12 and 6.98×10?12?L?1?S?1, respectively.