亚甲蓝分光光度法测定工业废水中阴离子洗涤剂的改进方法

以简化操作步骤,改进实验方法为目的。采用机械搅拌萃取的方法,节省了劳动力和工作时间,重要的是由于机械萃取更加彻底,不仅可以减少试验中每个样品中阴离子洗涤剂的加入量,也可大幅度提高实验的操作精度。另外,整个萃取过程可在通风橱内完成,避免了传统手工震摇方法,因三氯甲烷挥发而给实验操作人员造成的毒害。因此是对之前所有亚甲蓝分光光度法测定阴离子洗涤剂方法的一个提升和改进。     

SPECTROSCOPIC CHARACTERIZATION OF SOLVENT SOLUBLE FRACTIONS OF PETROLEUM VACUUM RESIDUES

ABSTRACT

NMR and FTIR spectroscopic techniques were used to investigate the effect of different solvent extraction schemes on the composition and chemical nature of species of vacuum residues of two Indian crude oils (namely Jodhpur and Heera) extractable into polar (ethyl acetate) and non-polar (n-pentane and n-heptane) solvents. The obtained soluble fractions were found to consist of mainly simple aliphatic and naphthenic ring structures, while insoluble fractions consisted primarily aromatic compounds. The results were used to draw inferences on the relative utility of different extraction schemes to upgrade vacuum residues as feedstocks for secondary conversion processes in petroleum industry.     

Pressurised solvent extraction of policosanol from wheat straw,germ and bran

Policosanols (PCs) are a group of long chain aliphatic alcohols that have been reported to have low-density lipoprotein (LDL) cholesterol-lowering properties. Wheat is a good source of these compounds. This study examined the effect of solvent type and temperature on extract yields and PC content and composition in the extracts. Wheat germ, straw and bran samples were extracted with petroleum ether, chloroform, n-hexane and ethanol at various temperatures ranging from 80 to 125 °C.     

Generalized mean for feature extraction in one-class classification problems

Biased discriminant analysis (BDA), which extracts discriminative features for one-class classification problems, is sensitive to outliers in negative samples. This study focuses on the drawback of BDA attributed to the objective function based on the arithmetic mean in one-class classification problems, and proposes an objective function based on a generalized mean. A novel method is also presented to effectively maximize the objective function. The experimental results show that the proposed method provides better discriminative features than the BDA and its variants.     

Magnetic Properties of Uranium Carbides after Neutron Irradiation

Fundamental investigations on valence control and solvent extraction of americium were carried out to develop a method for americium separation from reprocessing solution. In order to adjust americium valency from III to IV and VI, (NH₄)₁₀P₂W ₁₇O₆₁ synthesized was used as complexant stabilizing Am(IV). Oxidation behavior of americium was investigated as a function of (NH₄)₁₀P₂W ₁₇O₆₁ americium ratio. Using 0.1M (NH₄)₂S₂O₈ and 0.01M AgNO₃ as oxidation reagent, Am(IV) was obtained quantitatively at the ratio of 15. On decreasing the ratio to 0.6, 92% of americium was adjusted to Am(VI). The concentration of (NH₄)₂S₂O₈ could be reduced to 1/15 compared to the previously reported method in which no complexant was used. Americium(IV) was also prepared by reacting O₃ and AgNO₃ but no Am(VI) was obtained even at low (NH₄)₁₀P₂W ₁₇O₆₁ to americium ratio.

Americium(VI) could be extracted by tri-n-butyl phosphate stably without influence of (NH₄)₁₀P₂W ₁₇O₆₁. The distribution coefficient of Am(VI) was 4 between 100% tri-n-butyl phosphate and 1 M nitric acid, and separation factor from Nd(III) was 50.

With regard to the americium separation method which implemented valence control followed by extraction, adding (NH₄)₁₀P₂W ₁₇O₆₁ led to minimization of waste volume and improvement of extraction efficiency.     

The Oxidation Stability of Lubricating Oil

Abstract

Lubricating oil is generated throughout the year and collected in central locations in many communities. The studied lube oil has a boiling range of 280°C–400°C, and its physical properties were determined according to standard test methods in ASTM and International Petroleum. Solvent extraction by furfural was carried out using different feed ratios. The best ratio was 1:4 (sample:furfural). The oil was separated into its components using liquid column chromatography. It was found that the aromatic contents decreased. The structure group analysis was determined by infrared spectroscopy and refractive index-density-molecular weight methods. The oxidation stability was carried out according to ASTM method D-48 using an inhibitor. The inhibitor used was a nonionic surfactant, alkanolamide. The results showed that the oxidation stability improved using the inhibitor.     

End formation of a round tube into a square section having small corner radii

Expansion and reduction are the two common end forming processes for tubes. In the tube end expansion process using a square punch, it is difficult to obtain a small corner radii due to the stretching of the tube around the punch corners. The wall thickness around the corners is small when compared to the side wall. Hence, a tube having a poor square look is formed. In this study, a 2-stage end expansion of a round tube end into a square section having an improved square look i.e. small corner radii and increase in wall thickness around corners is developed. In the 1st stage, the tube end is flared into a cone shape using a 30° conical die by axial compression. In the 2nd stage, the conical end of the tube is drawn through a taper square die using a conical bottom square punch, and a near square section is formed. A 15% ironing ratio is applied during the drawing process to flatten the side wall of the square. Experimental and FEM simulation were performed to evaluate and to verify the forming process. Although the height of the square section increases when the punch stroke at the 1st stage is increased. However, this increase is limited by the buckling of the pipe at the circular section of the thick blank tube. Since the conical end is drawn into a square section having different radial lengths, the bottom of the square section is uneven. The uneven bottom end is trimmed off in the later process. A square section having a maximum height of 32 mm after trimming is successfully obtained from the experiment for the punch stroke, S = 44 mm using an API 5 L tube.     

Electrokinetic remediation: The use of mercury speciation for feasibility studies applied to a contaminated soil from Almadén

We have chosen the BCR (Bureau Communautaire de Référence) sequential extraction procedure as a speciation analysis to determine the mobility of mercury in the contaminated soil of the Almadén (Spain) mining district. This soil has a high mercury concentration (1000 mg kg⁻¹) in some areas. In previous works, the relationship between the weak-acid soluble fraction and the amount of contaminant recoverable by acid-enhanced electrokinetic remediation (EKR) was shown. In this study, after testing that this relationship is maintained, we test if similar relationships with chelating agents could be established. Recently, several chelating agents were tried and iodide was shown to be quite efficient for the removal of mercury. Thus we have carried out iodide-enhanced EKR experiments at the lab (16 g of soil) and semi-pilot (2 kg) scales. From these experiments it can be concluded that the amount of mercury recoverable by this technique is similar to the one recovered in the batch extraction experiments. Thus, this is another evidence that this kind of experiments can be used for the feasibility studies of the remediation technique. It is also shown that, although the removal efficiency is similar to the one obtained previously for in situ flushing, the time required to achieve this efficiency would be several orders of magnitude shorter for this soil.Nevertheless, the residual Hg present in the weak-acid soluble fraction of the speciation analysis of the soil after the EKR treatment increases with respect to the original contaminated soil, indicating a possible increase of the risks associated to the contaminated site. Therefore, a second EKR treatment is applied to the same soil, this time using acid-enhanced EKR. It is shown that, although almost no Hg was recovered with this technique for the original soil, an important amount can be recovered after the first treatment (iodide-enhanced EKR). Also it is shown that the design and operation of this second technique should be studied carefully due to the rather complex chemistry of the species involved.