Fatty acids from Macoma sp. of bivalve mollusc

Fatty acids of the total lipids of flesh and hepatopancreas of Macoma sp. have been determined. The level of 20:5w3 (ca 17%), a biologically important fatty acid, was found to be considerably high. Other major component fatty acids were 16:0, 16:1, 18:1 and 22:4w6. High levels of 22:5w6 (8%), 22:5w3 (8%) and 22:6w3 (ca 15%) were found in flesh lipid. Nonsaponifiables were also high (28–30%). Alkyl ether acyl glycerols were found in flesh (1.3%) and hepatopancreas (3.8%).     

Gas hold-up in highly viscous pseudoplastic non-newtonian solutions in three phase sparged reactors

Gas hold-up structure was studied in a three phase sparged reactor of 200 mm diameter. Air and aqueous solutions of carboxymethyl cellulose were used as gas and liquid phases. Spherical glass beads formed the solid phase. The superficial gas velocity, rheological properties, particle size and solid loading were varied over a wide range and their effects on gas hold-up structure were studied. A correlation for the estimation of the gas hold-up as a function of superficial gas velocity, apparent liquid viscosity, particle settling velocity and solid loading was established.     

Occurrence of wax esters and 1-O-alkyl-2,3-diacylglycerols in goat epididymal sperm plasma membrane

Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/¹H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C₁₄ to C₂₂. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C₂₀–C₂₉ carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl glycerol ethers.     

Synthesis of BaTiO<Subscript>3</Subscript> powder from barium titanyl oxalate (BTO) precursor employing microwave heating technique

Cubic barium titanate (BaTiO₃) powder was synthesized by heating barium titanyl oxalate hydrate, BaTiO(C₂O₄)₂·4H₂O (BTO) precursor in microwave heating system in air at 500°C. Heating BTO in micro-wave above 600°C yielded tetragonal form of BaTiO₃. Experiments repeated in silicon carbide furnace showed that BaTiO₃ was formed only above 700°C. The product obtained was cubic.     

Recipes for Spatial Statistics with Global Datasets: A Martian Case Study

The Mars Odyssey Gamma Ray Spectrometer has yielded planetary data of global extent. Such remote-sensing missions usually assign the value of a continuous-valued geospatial attribute to a uniform latitude-longitude grid of bins. Typical attributes include elemental-mass fraction, areal fraction of a mineral type, areal fraction of rocks, thermal inertia, etc. The fineness of the grid is chosen according to the spatial resolution of the orbiter and concomitant data processing. We describe methods to maximize the information extracted from both bin and regional data. Rigorous use of statistical parameters and related methods for inter- and intra- regional comparisons are also discussed. While we discuss results from the Mars Odyssey mission, the techniques we describe are applicable whenever continuous-valued attributes of a planet’s surface are characterized with bins and regions. Our goal is to distill the simplest statistical methods for regional comparisons that would be intuitively accessible to planetary scientists.     

Impact of Variable Packet Length on the Performance of Heterogeneous Multimedia Wireless Sensor Networks

Wireless Personal Communications - Performance valuation of wireless sensor network (WSN) routing protocols calls for realistic data traffic models because of their application specific nature....     

Oxidation of oleanolic acid ofAvicennia officinalis leaves to oleanonic acid in the natural environment of Sunderban mangrove ecosystem

Oleanolic acid, a major component pentacyclic triterpene in the leaves ofAvicennia officinalis was found to be oxidized to oleanonic acid in the natural environment of Sunderban mangrove forest.Presented in part at the All India Symposium on Marine Plants, held on Oct. 30–Nov. 1,1983 at National Institute of Oceanography Dona Paula, Goa India.     

Fault size diagnosis of rolling element bearing using artificial neural network and dimension theory

Neural Computing and Applications - Failure of roller bearings can cause downtime or a complete shutdown of rotating machines. Therefore, a well-timed detection of bearing defects must be...     

An ice-water model study on formation of blowhole-free skin with reference to solidification of steel

A cold model investigation on the formation of blowhole-free initial skin was undertaken in the laboratory by freezing water containing dissolved carbon dioxide. Plane front unidirectional solidification was simulated. Experiments were conducted in a stagnant bath to study the effect of CO₂ concentration in water and the rate of solidification on blowhole-free skin thickness. Some experiments were also conducted with artificial gas bubbling. Initially, the variation of thickness of ice with time deviated from the parabolic rate law of solidification. The thickness of blowhole-free skin decreased with increasing concentration of dissolved CO₂ and solidification rate. Mild stirring increased the thickness of blowhole-free skin. Differential equations, along with requisite initial and boundary conditions, were solved by a numerical analysis technique to compute the concentration of CO₂ in water at the moving ice-water interface. This revealed that very small supersaturations were required to form blowholes although the experiments were conducted under very clean and controlled conditions. Implications of some of the findings in connection with solidification of steel are indicated.