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排序方式: 共有163条查询结果,搜索用时 31 毫秒
1.
Preparation and surface- active properties of polyoxyethylene-glycol (600) monoesters of fatty acids
T. Chandrasekhara Rao Y. Sita Rama Sastry R. Subbarao Gollamudi Lakshminarayana 《Journal of the American Oil Chemists' Society》1977,54(1):15-16
Polyoxyethyleneglycol (PEG-600) monoesters of undecylenic, lauric, myristic, palmitic, stearic, oleic, ricinoleic and 12-hydroxystearic
acids were prepared in 80-85% yield by reacting PEG with boric acid, esterifying the resultant borate with fatty acid, and
selectively hydrolyzing the borate ester; their surface active properties were evaluated. Increase in acyl chain length increased
the surface tension. The presence of a double bond or hydroxyl group in C18 series improved the wetting and emulsifying proper-ties. Unsaturation in the fatty acid chain reduced the foaming power. 相似文献
2.
T. Chandrasekhara Rao G. Lakshminarayana N. B. L. Prasad S. Jagan Mohan Rao G. Azeemoddin D. Atchyuta Ramayya S. D. Thirumala Rao 《Journal of the American Oil Chemists' Society》1984,61(9):1472-1473
The seeds and extracted oils ofCarissa spinarum (Apocynaceae), (I),Leucaena leucocephala (Leguminosae) (II) andPhysalis minima (Solanaceae) (III) were analyzed for characteristics and compositions. The seeds of I, II and III contained 22.4, 6.4 and
40.0% oil and 10.1, 27.6 and 17.9% protein, respectively. The oils of I, II and III had, respectively, iodine values 70.1,
113.5 and 122.5; saponification values 186, 188 and 189; unsaponifiable matter 5.2, 2.5 and 0.8%, and the following fatty
acid compositions (area %): palmitic 12.6, 14.2, 10.5; stearic 7.6, 6.1, 8.6; oleic 72.7, 20.1, 17.3; linoleic 5.2, 53.8,
61.4; linolenic 0.9, 1.8, 0.0, and arachidic 1.0, 2.3, 0.0. II contained 1.7% lignoceric acid. III contained small amounts
of hexadecenoic (0.1%), epoxy (0.6%) and hydroxy (1.5%) fatty acids. 相似文献
3.
Source strength distribution on a jet boundary was obtained from measurements using the principle of acoustic holography.
Measurements were conducted in an open field. Measurement of acoustic pressure on a cylindrical two-dimensional contour located
close to the vibrating jet boundary was used to obtain the acoustic source strength distribution at the jet boundary. Particular
attention was focussed on back projection of the sound field on to a cylindrical surface. A jet emanating from 5 mm convergent
nozzle was used for the holography experiments, assuming axisymmetry. Experimental results were compared with results obtained
from holography 相似文献
4.
5.
K. Rusek A. M. El-Naggar A. Albassam G. Lakshminarayana M. Kolcun M. Chmiel G. Myronchuk 《Journal of Materials Science: Materials in Electronics》2016,27(7):6745-6749
In this work, we demonstrate a possibility to use La–Ga–S–O–Gd glass polymer nanocomposites as effective materials for photo-induced birefringence. Here we chose PVA as a photopolymer matrix. The photo-induced effects were studied using 8 ns Nd: YAG laser generating bicolor coherent light beams with wavelengths 1064, and 532 nm. The detection of the photo-induced birefringence was carried out using cw He–Ne laser at 1150 nm. The optimal concentration of the nanoglass favoring maximal changes of refractive indices is established. The photo-induced laser power density was changed up to 0.9 GW/cm2. The photo-induced beams were incident at angles varying within the 32° and 52° with respect to the nanocomposite planes. The polarizations of the beams did not play principal role. We discovered an appearance of maximal birefringence equal to about 0.078. The effect is strongly dependent on the nanoparticle sizes and is completely reversible after switching off the laser treatment within several milliseconds. Such features are useful for the recording of optical information and production of gratings with desirable periods. 相似文献
6.
Muthumanickam Agilan Gandham Phanikumar Dhenuvakonda Sivakumar 《Transactions of the Indian Institute of Metals》2018,71(11):2667-2670
In this study, weld solidification cracking behaviour of AA2195 Al–Cu–Li alloy was studied and compared with conventional AA2219 and AA2014 aluminium alloys. Cracking susceptibility was evaluated using varestraint test and Gleeble® hot ductility test and the slope of liquidus temperature as function of liquid fraction was also evaluated. Solidification cracking susceptibility of AA2195, AA2219 and AA2014 alloys was ranked based on the above methods. Consistent trend in cracking susceptibility was observed in all the methods where AA2195 and AA2219 alloys showed highest and lowest cracking susceptibility, respectively. 相似文献
7.
Shah Naishalkumar Rahul M. R. Phanikumar Gandham 《Metallurgical and Materials Transactions A》2021,52(5):1574-1580
Eutectic high entropy alloy with seven components is designed based on the integrated computational materials engineering (ICME) framework. The framework includes thermodynamic prediction using calculation of phase diagrams (CALPHAD), microstructure simulation using phase-field method, and experimental validation. The designed alloy shows the eutectic structure consisting of FCC and laves phase in the composition range from 8.25 to 10 at. pct Ta. The simulation and experimental results are co-related and a framework is proposed that can be used for high entropy alloy design subjected to various manufacturing processes.
相似文献8.
Vijay Kale R. Subbarao G. Lakshminarayana M. Bhagwant Rao 《Journal of the American Oil Chemists' Society》1991,68(8):583-584
C36 Dimer acids were esterified with various short-chain alcohols, namely 2-propanol, n-butanol, n-hexanol, n-octanol, 2-octanol
and 2-ethyl-1-hexanol by using sulfuric acid as catalyst and benzene as an azeotropic solvent. Various reaction parameters
were standardized. In case of isopropyl esters, acid-to-alcohol mole ratio of 1:5 and sulfuric acid concentration of 2% based
on the weight of dimer acids were found to be optimum. In case of straight-chain primary alcohols, namely n-butanol, n-hexanol
and n-octanol, 1:2.5 mole ratio of acid to alcohol and 1% by weight of sulfuric acid were found satisfactory. Esterification
reaction rates were determined from the fall in acid value of the product. The reaction followed pseudo first order kinetics.
The reaction rates increased with the increase in chainlength of straight-chain primary alcohols from n-butanol to n-octanol.
The rate of reaction decreased from n-octanol to 2-ethyl-1-hexanol to 2-octanol due to the branching of the chain in 2-ethyl-1-hexanol
and secondary nature of the −OH group in 2-octanol. 相似文献
9.
S. Lakshminarayana 《Knowledge》2009,22(1):100-104
With the advent of technology man is endeavoring for relevant and optimal results from the web through search engines. Retrieval performance can often be improved using several algorithms and methods. Abundance in web has impelled to exert better search systems. Categorization of the web pages abet fairly in addressing this issue. The anatomy of the web pages, links, categorization of text and their relations are empathized with time. Search engines perform critical analysis using several inputs for a keyword(s) to obtain quality results in shortest possible time. Categorization is mostly done with separating the content using the web link structure. We estimated two different page weights (a) Page Retaining Weight (PRW) and (b) Page Forwarding Weight (PFW) for a web page and grouped for categorization. Using these experimental results we classified the web pages into four different groups i.e. (A) Simple type (B) Axis shifted (c) Fluctuated and (d) Oscillating types. Implication in development of such categorization alleviates the performance of search engines and also delves into study of web modeling studies. 相似文献
10.
Jaroslav Stejskal Pavel Kratochvíl Josef Urban G. S. Kapur Y. Lakshminarayana 《Polymer International》1993,30(1):81-87
Methyl methacrylate was polymerized in an aqueous medium in the presence of gelatin using potassium persulfate as initiator. The dispersion mode of polymerization, when the monomer is completely miscible with water, was investigated and compared with an emulsion process, which proceeds at higher monomer concentration. Spherical and relatively uniform polymer particles were formed. Macroscopic precipitation of polymer is prevented by combination of the steric stabilization by grafted gelatin and of repulsive electrostatic interactions from the initiator residues attached to the particle surface. Static and dynamic light scattering have been used to determine the molar mass (molar mass of the whole dispersion particle, MwD ~ 108-109 g mol?1) and hydrodynamic radius (RhD ~ 50-120 nm) of the particles. The number of particles per unit volume does not depend on overall monomer concentration, and it is higher, and therefore the particle size is smaller, than that observed for the soapless emulsion polymerization. The addition of gelatin may be thus used to modify the particle size. Acrylonitrile dispersions were prepared under similar conditions. Unlike methyl methacrylate, this monomer does not swell the polymer particles. While poly(methyl methacrylate) particles are spherical and relatively uniform, the polyacrylonitrile dispersions consist of polydisperse aggregates of tiny polymer particles. 相似文献