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121.
This paper describes work aimed at producing a high‐quality transformer oil from local Egyptian paraffinic base stock by hydrogenation, or hydrogenation plus sulphonation. Analysis showed that the neutral base oil 70N was suitable for producing transformer oil. This neutral base oil was chemically treated by hydrogenation under various conditions of temperature, pressure, and time, using two different catalysts, and by hydrogenation followed by sulphonation using optimum conditions. Optimum hydrogenation conditions were achieved by using a Ni/Mo (10 wt. %) catalyst, at 275°C and 100 psi pressure for 60 min, while optimum sulphonation conditions were achieved in previous work by using oleum or SO3 gas at a concentration of 6 wt. % at 35°C for 60 min. Laboratory results and field trials indicated that the neutral paraffinic base oil when so treated meets the IEC 296 international specification for transformer oil, with the exception of the pour point (−18°C). However, this pour point is not relevant in certain hot climatic conditions. Evaluation of the treated oil with commercial transformer oil has shown its potential for use.  相似文献   
122.
A robust element distortion metric, based on the new concept of mid‐node admissible spaces, for two‐dimensional quadratic triangular finite elements is developed. The metric is based on the Jacobian determinant over the entire element, without requiring that it actually be computed everywhere on the element. The metric is relatively inexpensive to compute, especially for mildly distoted elements. The metric is able to detect elementsof poor quality that other distortion metrics fall to detect. It also has the ability to approve elements of good quality regardless of the extent to which they may appear geometrically distorted. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
123.
Polyaniline was prepared by chemical methods. Its electrical conductivity was measured. The electrical conductivity of polyaniline salt and polyaniline base were compared with composites prepared by the hot press of polyaniline base with KBr, Co(CH3COO)2, and picric acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1658–1665, 2000  相似文献   
124.
Two novel organotin monomers, (N‐tri‐n‐butyltin) maleimide and m‐acryloylamino‐(tri‐n‐butyltin benzoate), were synthesized. Copolymerization of these two monomers with styrene was carried out in the bulk at 65°C using asobisisobutyronitrile as the free radical initiator. The monomers and copolymers were characterized by elemental analysis; the molecular weights of the copolymers were determined by GPC, solubility, IR, and 1H‐NMR spectral studies. The antibacterial activities of the synthesized organotin monomers and copolymers toward various types of bacteria were also reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 740–745, 2000  相似文献   
125.
The morphological and chemical characteristics of ten varieties of sugar beet roots were evaluated during the season of 1996–1997. The best morphological characteristics were found in Top, Ito and Pamela varieties. The highest expected technological yield of sugar was found in Pamela and Top. The chemical constituents of different varieties of sugar‐beet roots showed significant differences. The suitability of sugar beet juice for preparing beet syrup as a new product was also evaluated and compared with sugar cane syrup. Purified beet‐syrups concentrated under vacuum or under atmospheric pressure showed more stability during storage than sugar cane syrup. The effect of storage conditions (at cold storage and at room temperature) and packaging materials (glass and polyethylene high‐density bottles) on properties of beet‐syrup and sugar cane syrup were also studied.  相似文献   
126.
Phenethyl isothiocyanate (PEITC), a compound derived from cruciferous vegetables, has garnered attention for its anticancer properties. This review synthesizes existing research on PEITC, focusing on its mechanisms of action in combatting cancer. PEITC has been found to be effective against various cancer types, such as breast, prostate, lung, colon, and pancreatic cancers. Its anticancer activities are mediated through several mechanisms, including the induction of apoptosis (programmed cell death), inhibition of cell proliferation, suppression of angiogenesis (formation of new blood vessels that feed tumors), and reduction of metastasis (spread of cancer cells to new areas). PEITC targets crucial cellular signaling pathways involved in cancer progression, notably the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), Protein Kinase B (Akt), and Mitogen-Activated Protein Kinase (MAPK) pathways. These findings suggest PEITC's potential as a therapeutic agent against cancer. However, further research is necessary to determine the optimal dosage, understand its bioavailability, and assess potential side effects. This will be crucial for developing PEITC-based treatments that are both effective and safe for clinical use in cancer therapy.  相似文献   
127.
Forced in-plane flow of liquids through contiguous flat and curved regions of confined fabrics has been studied both as a general phenomenon and for predicting the flow of polymers during injection molding of monolithic composite structures with complex configurations. A controlled pressure difference is applied to drive the flow, while the mass flow rate is measured gravimetrically by Liquid/Air Displacement Analysis (LADA). Measurements have been carried out along fabric paths that are first vertical, then curved, and finally horizontal. Fluid flow equations have been adapted for analyzing flow in the flat sections, leading to the evaluation of permeability constants and capillary pressures. A saturated flow rate measured at constant hydrodynamic pressure is used to evaluate the overall permeability coefficient of the encapsulated fabric. Data are presented showing that permeability can be reduced as a consequence of flow through the curved region.  相似文献   
128.
This paper reports the synthesis of highly conductive niobium doped titanium dioxide (Nb:TiO2) films from the decomposition of Ti(OEt)4 with dopant quantities of Nb(OEt)5 by aerosol‐assisted chemical vapor deposition (AACVD). Doping Nb into the Ti sites results in n‐type conductivity, as determined by Hall effect measurements. The doped films display significantly improved electrical properties compared to pristine TiO2 films. For 5 at.% Nb in the films, the charge carrier concentration was 2 × 1021 cm?3 with a mobility of 2 cm2 V–1 s–1 . The corresponding sheet resistance is as low as 6.5 Ω sq–1 making the films suitable candidates for transparent conducting oxide (TCO) materials. This is, to the best of our knowledge, the lowest reported sheet resistance for Nb:TiO2 films synthesized by vapour deposition. The doped films are also blue in colour, with the intensity dependent on the Nb concentration in the films. A combination of synchrotron, laboratory and theoretical techniques confirmed niobium doping into the anatase TiO2 lattice. Computational methods also confirmed experimental results of both delocalized (Ti4+) and localized polaronic states (Ti3+) states. Additionally, the doped films also functioned as photocatalysts. Thus, Nb:TiO2 combines four functional properties (photocatalysis, electrical conductivity, optical transparency and blue colouration) within the same layer, making it a promising alternative to conventional TCO materials.  相似文献   
129.
Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO106PO70EO106) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N2 adsorption, 29Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g−1 in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3.  相似文献   
130.
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