Evaluation of water glycol hydraulic fluids: a tribological approach

Water glycol fluids are commonly used as fire‐resistant hydraulic fluids, particularly in areas where fires cannot be tolerated, such as foundries, steel mills and mines. However, they have the disadvantage that their wear resistance is unsatisfactory. Hence, there is a need for an additive package which overcomes this poor wear resistance. In order to design an effective water glycol hydraulic fluid for this purpose, four additive packages were considered. The performance of the lubricant composition developed with these packages is studied in detail. The physico‐chemical and tribological properties of the formulations were determined using standard methods. The load‐carrying properties were studied by four‐ball and Timken load methods. The antiwear performance and coefficient of friction were studied by using four‐ball and Schwingung Reibung Verschleiss test methods. The topography and surface analysis were carried out using scanning electron microscopy and X‐ray photoelectron spectroscopy techniques. Copyright © 2006 John Wiley & Sons, Ltd.     

TiO2 nanotube membranes on transparent conducting glass for high efficiency dye-sensitized solar cells

Crack-free TiO(2) nanotube (NT) membranes were obtained by short time re-anodization of a sintered TiO(2) NT array on Ti foil, followed by dilute HF etching at room temperature. The resulting freestanding TiO(2) membranes were opaque with a slight yellow color having one end open and another end closed. The membranes were then fixed on transparent fluorine-tin-oxide glass using a thin layer of screen-printed TiO(2) nanoparticles (NPs) as a binding medium. It was found that low temperature treatment of the resulting NT/NP film under appropriate pressure before sintering at 450?°C was critical for successful fixation of the NT membrane on the NP layer. The resulting films with open-ends of NT membranes facing the NP layer (open-ends down, OED, configuration) exhibited better interfacial contact between NTs and NPs than those with closed-ends facing the NP layer (closed-ends down, CED, configuration). The cells with an OED configuration exhibit higher external quantum efficiency, greater charge transfer resistance from FTO/TiO(2) to electrolyte, and better dye loading compared to CED configurations. The solar cells with the OED configuration gave 6.1% energy conversion efficiency under AM1.5G condition when the commercial N719 was used as a dye and I(-)/I(3)(-) as a redox couple, showing the promise of this method for high efficiency solar cells.     

3D Multilayer Mesh NoC Communication and FPGA Synthesis

Wireless Personal Communications - Network on chip (NoC) is the latest approach in which multiprocessors are integrated in a single chip and FPGA implementation makes it scalable and...     

Recent progress in carbazole based polymers

This review highlights the recent developments in carbazole based polymer systems which have taken place along three main directions: (a) syntheses of homopolymers, copolymers, copolycondensates and copoly(step) polymers containing pendant carbazole units linked to the main chain directly or through flexible units; (b) chemical modification of these polymer systems to cation radical complexes, nuclear substituted polymeric materials, ion-exchange resins, charge-transfer complexes, copolymeric materials containing donor-acceptor units; and (c) syntheses of polymer systems containing carbazole units in the main chain such as polyamides, polyimides, polyarylates, polysulphones, polymeric azo-dyes, polysiloxanes, polyquinone and miscellaneous carbazole-incorporated polymer systems. These polymers of tailored chemical structures exhibit outstanding and interesting thermal, electrical, photoelectrical, ion-exchange and other physico-chemical properties, which have been discussed and rationalized in the light of the structural characteristics of these polymer systems.     

Polymerization of N-vinylcarbazole over cobalt (II) exchanged 13X molecular sieves

Polymerization of N-vinylcarbazole over Co(II)-13X molecular sieves in toluene solution has been studied. The rate of polymerization has been observed to be second order both in monomer concentration and in the exchange level of Co(II), and linearly dependent on catalyst loading. An apparent activation energy of 8.71 kcal mol^?1 (36.41 kJ mol^?1) has been found for the polymerization. The effect of different parameters on molecular weight has also been studied. The general kinetic features of the reaction are somewhat different from those reported for monomers like isobutyl vinyl ether, styrene etc. on simple and rare earth exchanged 13X molecular sieves.     

Fatty Acid Composition Including Trans‐Fatty Acids in Edible Oils and Fats: Probable Intake in Indian Population

Abstract: The susceptibility of trans‐fat to the human health risk prompted the Food and Agriculture Organization (FAO) and World Health Organization (WHO) to prepare regulations or compulsory claims for trans‐fatty acids (TFA) in edible oils and fats. In this study, analysis of fatty acid composition and TFA content in edible oils and fats along with the possible intake of trans‐fat in Indian population was carried out. The analysis was carried out as per the Assn. of Official Analytical Chemists (AOAC) methodology and the results were statistically analyzed. The average TFA content in nonrefined mustard and refined soybean oils exceeded by 1.16‐ to 1.64‐fold as compared to the Denmark limit of 2% TFA in fats and oils destined for human consumption. In branded/nonbranded butter and butter oil samples, average TFA limit exceeded by 4.2‐ to 9.5‐fold whereas hydrogenated vegetable oil (HVO) samples exceeded the limit by 9.8‐fold, when compared to Denmark standards. The probable TFA intake per day through different oils in Indian population were found to be less than WHO recommendation. However Punjab having highest consumption of HVO (–15 g/d) showed 1.09‐fold higher TFA intake than the WHO recommendation, which is alarming and may be one of the factors for high cardiovascular disease mortality rate that needs further elucidation. Thus there is a need to prescribe TFA limit for edible oil, butter, and butter oil in India and to reduce the already proposed TFA levels in HVO to safeguard the health of consumers. Practical Application: The probable daily intake of trans‐fatty acid (TFA) especially through hydrogenated vegetable oil (HVO) was assessed. In absence of any specification for TFA and fatty acid composition for edible oils, butter, and butter samples, a pressing need was felt to prescribe TFA limit in India. The study indicates that TFA intake through HVO consumption is higher in States like Punjab than the recommended daily intake prescribed by WHO. Hence, strategies should be adopted to either decrease the consumption of HVO or to modify the industrial processing method of HVO with less content of TFA to safeguard the health of consumers.     

Common fallacies in estimation and control under uncertainty

Examples from the literature are used to illustrate certain common fallacies in the development of estimators and controllers under uncertainty. It is shown that the common notions of process, model, objective, and method must carefully be distinguished from one another and from additional concepts of attitude and best strategy. Failure to do so can readily lead to false claims and sub-optimal, or even useless, schemes. Concrete guidelines are provided to avoid the fallacies and to better focus the research effort.     

Synthesis of beaded and entwined carbon nanofibers in Ni:Al alloy catalyst

This paper reports two new types of carbon nanofibers synthesis by thermal decomposition of n-hexane in presence of Ni-Al alloy in hydrogen atmosphere at 1100 degrees C. One type is "beaded fibers" in which spherical carbon beads (approximately 1 microm) are regularly grown from outer surface of fibers (approximately 0.3 microm). The other new microstructure is "entwined fibers" in which multiple nanofibers of diameter approximately 100 nm grow self-entwined like a braid of hair. Both bead-fiber bonding (in beaded fibers) and fiber-fiber interaction (in entwined fibers) are strong to be detached/unfolded by 30-min ultrasonication.