Dry Fractionation Approach in Concentrating Tocopherols and Tocotrienols from Palm Fatty Acid Distillate: A Green Pretreatment Process for Vitamin E Extraction

Palm fatty acid distillate (PFAD) is a rich source of vitamin E. As compared to other vegetable oil, PFAD has higher tocotrienol (70–80%) over tocopherol content, which makes it a valuable source for vitamin E extraction. Current vitamin E extraction methods are not sustainable due to the intensive usage of chemical and high operational cost. Hence, the present study investigated for the first time using dry fractionation process as a green and economical pretreatment method for separating solid fraction (stearin) and liquid fraction (olein) in order to concentrate vitamin E from PFAD in olein fraction. We examined the dry fractionation conditions: crystallization ending temperature (36–44 °C), cooling rate (0.3 and 1.5°C min⁻¹), stirring speed (20–125 rpm), and holding time (0–60 min) on the composition of unsaturated and saturated fatty acids as well as vitamin E content in liquid fraction (olein) and solid fraction (stearin) using gas chromatography and high performance liquid chromatography, respectively. In most of these conditions, vitamin E was ultimately higher in olein fraction as compared to stearin fraction, which is correlated with the high degree of unsaturation. Under a cooling rate of 0.3°C min⁻¹, 90 rpm stirring speed, and ending crystallization of 38 °C, the highest vitamin E rich olein fraction was attained with 1479 ± 10.51 ppm in 50 g olein fraction as compared to 1366 ± 7.94 ppm in 500 g of unfractionated PFAD.     

重庆建筑与风土人情

通过对重庆两个旧居住区的调研,探讨山城建筑艺术与特点,以及具有民俗个性的生活空间,为今后的重庆建筑发展及旧区保护等问题的解决,提供素材。     

纤维素/聚乙烯醇共混物相容性的研究

本研究以二甲基亚砜(DMSO)—四乙基氯化铵溶剂体系制成纤维素/聚乙烯醇共混物,并采用粘度法、热分析法、X—射线衍射法和动态力学性能测定等对共混物中两种组分的相容性进行了分析与讨论。     

三角胶带传动动态应力应变测定的研究

三角胶带动态应力应变的试验装置和测量,目前,只能测定带速在2.5米/秒以下(转速最高为350转/分)的传动,与实际中一般应用5米/秒以上的情况尚有距离。本文为提高带速,新设计了简便易行的试验装置。其试验带速达7.5米/秒(转速为1000转/分),甚至可达更高速度。同时,自行设计了专用的测量电路,满足了本试验的需要。文中首次把大应变量金属丝应变片应用于三角胶带测试。由于试验带速的提高,满足了三角胶带实际工作要求,有助于深入研究带的疲劳强度和寿命。     

Synthesis and Characterization of Some Triphenyltin(IV) Complexes from Sterically Crowded [((E)-1-{2-Hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate Ligands and Crystal Structure Analysis of a Tetrameric Triphenyltin(IV) Compound

Four new triphenyltin(IV) complexes containing [((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate ligands (L) have been synthesized with formulations of Ph₃SnLH. They have been studied by multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, ¹¹⁹Sn M?ssbauer and IR spectroscopy. A full characterization of one complex, Ph₃SnL¹H (1), was accomplished by single crystal X-ray crystallography, which revealed the compound to be a macrocyclic tetramer. In the tetramer, the five coordinate tin atoms have distorted trigonal bipyramidal geometries with the three phenyl groups occupying equatorial positions, while an oxygen atom of the carboxylate group of one L ligand and the oxide O-atom (formerly the hydroxy group) of a second L ligand in an apical positions. The carboxylate ligands bridge adjacent tin atoms and coordinate in the zwitterionic form with the phenolic proton moved to the nearby nitrogen atom. ¹¹⁹Sn NMR results indicate that the tetrameric structures of the complexes in the solid state, in which the tin atoms are five-coordinated, dissociate in solution to yield four coordinate monomeric species.     

Hybrid control of graphite cast iron structure by partial melt treatment process

The Modified Inmould Process, which forms a cast iron-graphite hybrid alloy with a spheroidal/flake graphite structure (SG/FG), has been developed by the author.^1-3 Though this process can easily control the transitional structure of SG/FG, there are some mild restrictions caused by rapid collision during the mixing of molten metals in the mould on pouring. In this study, a new experimental process was designed to solve this difficulty. The plate-like mould cavity was separated into a reaction chamber (RC) and a product cavity by a thin dam. An alloy of FeSiMg for spheroidization of base molten metal was prepared in the reaction chamber. Molten metal was poured up from the bottom of the product cavity and a part of it flowed over the dam into the reaction chamber. After being spheroidized in the reaction chamber, spheroidal graphite (SG) iron melt flowed backward into the product cavity. The density of SG molten iron with a higher carbon equivalent value is generally lower than that of flake graphite (FG) molten metal. Thus SG molten metal moved into the upper end of the product cavity by replacement of the base metal, while the base metal remained stationary at the lower end of the cavity. As a result of the phenomena of flow, movement and replacement between mutual melts, a SG/FG transitional layer structure was formed, downward, throughout the cast product.     

STUDY ON THE OXIDIZABILITY-RESISTANCE OF FLEXIBLE GRAPHITE BY USING ADDITIVE

Abstract: The oxidizability-resistance of graphite products havebeen studied with the addition of H_3PO_4 and H_3BO_3. A available way hasbeen found to increase the oxidizability-resistance of graphite products.The oxidizability-resistance of graphite products rises remarkably aftertreating with 1% H_3PO_4 and 3% H_3BO_3. Meanwhile, the relative princi-ple has been proposed also.     

Damages of windings of a three-phase slip-ring induction machine having parallel paths in the stator or in the rotor

Contents The following damages of a three-phase slip-ring induction machine having parallel paths in the stator or in the rotor are analysed in the paper: break in a parallel path of the stator or the rotor winding, internal short-circuit in the stator winding, earth fault of the stator winding. The mathematical model of asymmetrical states is presented. For the case of existence of the parallel paths in the windings, specific action of the space harmonics of the magnetic field, deformed as a result of internal asymmetry, is described.

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Wicklungsschäden der Dreiphasen-Schleifringläufer-maschine mit parallelen Wicklungszweigen im Stator oder RotorTeil 1: Das mathematische Modell

Übersicht In dem Aufsatz werden die folgenden Schäden der Dreiphasen-Schleifringläufermaschine mit parallelen Wicklungszweigen im Stator oder Rotor analysiert: Unterbrechung von parallelen Wicklungszweigen, innerer Kurzschluß in der Statorwicklung, Erdschluß. Das mathematische Modell von unsymmetrischen Zuständen wird dargestellt. Die spezifische Wirkung der Raumharmonischen, des infolge der inneren Unsymmetrie deformierten magnetischen Feldes, wird für den Fall des Vorhandenseins von parallelen Wicklungszweigen beschrieben.

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Part 2: Arch. Elektrotech. 71 (1988) 269–274     

异弹模界面裂缝应力强度因子的计算

本文将分区混合有限元用于计算异弹模界面裂缝应力强度出子,扩大了分区混合有限元的应用范围。由实例说明,数字计算结果与试验值相当符合。     

球-矩形窗口在聚类趋势检验中的效

本文讨论Hopkins统计量在球-矩形窗口内应用时对聚类趋势检验的效。Monte-Carlo模拟结果和对IMOX数据的实际检验说明,如果聚内是致密的,聚间是良好分开的,那么以Hopkins统计量和球-矩形窗口为模型建立的聚类趋势检验是有效的。