The oscillation of a spheroid along its axis in a non-Newtonian fluid

Summary The present paper investigates the nature of the fluid flow when a spheroid is suspended in an infinitely extending elastico-viscous fluid defined by the constitutive equations given byOldroyd orRivlin andEricksen, and is made to perform small amplitude oscillations along its axis. The solution of the vector wave equation is expressed in terms of the solution of the corresponding scalar wave equation, without the use ofHeine's function or spheroidal wave functions. Two special cases (i) a sphere and (ii) a spheroid of small ellipticity, are studied in detail.Née MissRenuka Rajagopalan.     

An Investigation into Fiber Dispersion Behavior in Water with Reference to Wet-Lay Nonwoven Technology

This article reports on fiber dispersion behavior in water with reference to wet-lay nonwoven technology. The effects of fiber material characteristics and dispersion process conditions on the quality of the nonwoven webs were examined. The webs were characterized for their area-based uniformity by means of an imaging system in conjunction with quadrat analysis. It was found that the area occupied by the fibers in the webs followed the lognormal probability distribution and the angular orientation of the fibers in the webs followed the bimodal distribution. The web prepared by using scoured fibers was almost equally uniform as compared to the web prepared by using bleached fibers. The web made up of shorter and coarser fibers was more uniform than that made up of longer and finer fibers. The higher concentration of cationic surfactant resulted in more uniform webs. It was observed that the webs prepared at optimum stirring rate and dispersion time were found to possess the highest uniformity.     

Synthesis,Thermal Properties,and Radiolysis of Poly(Cyclohexyl α-Chloroacrylate)

Cyclohexyl α-chloroacrylate (CCA) was polymerized by radical anionic and γ-radiation initiation. The anionic polymerization of cyclohexyl α-chloroacrylate gave moderately isotactic polymer in toluene and syndiotactic-rich polymer in THF. Poly(cyclohexyl α-chloroacrylate) (PCCA) was found to undergo two-stage weight loss in thermogravimetric analysis, and the first-stage weight loss was attributed to the lactonization reaction. PCCA degraded under γ-radiation, and the radiation yields of crosslinking and scission, G _x and G _s, were 0.6 and 3.8, respectively.     

X-ray spectroscopic investigation of some spinel structures

K-absorption edges of cations in the manganites of magnesium, nickel, copper, zinc and cadmium and ferrite samples of composition, Mg_1?x Mn_x Fe₂O₄ (x=0, 0·25, 0·50, 0·75, 1·0), have been recorded employing a 40 cm curved mica crystal spectrograph of transmission type. It is observed that the absorption edges for the specimen shift towards the shorter wavelength side of the metal edge position. Shifts of both the absorption edges and the main absorptoin peaks for ferrites and manganites have been compared with compounds in which the oxidation state of the cation is well known. It is found that the manganese ions in these ferrites and manganites exist in valence states two and three respectively while iron in the ferrite samples is present in oxidation state three. An attempt has been made to interpret the observed absorption edge features in the light of neutron and X-ray diffraction studies on the same ferrite and manganite samples.     

Quantitative chiral analysis of phthaloylglutamic acid and related analogs by a single ratio kinetic method using electrospray ionization and matrix-assisted laser desorption techniques

A rapid method for quantitative chiral analysis of phthaloylglutamic acid and its dimethyl ester by Cook's kinetic method is demonstrated using electrospray ionization (ESI) and matrix-assisted laser desorption techniques. Transition-metal-bound complex ions containing the chiral phthaloylglutamic acid and its dimethyl ester are generated by ESI mass spectrometry and subjected to collision-induced dissociation. The ratio of the two competitive dissociation rates is related to the enantiomeric composition of the drug mixture. A seven-point calibration curve, derived from the kinetic method, allowed rapid quantitation of the enantiomeric excess of drug mixtures. In this paper, matrix-assisted laser desorption/ionization (MALDI) coupled with the linear ion trap (LIT) technique is evaluated for its applicability as a complementary technique to ESI for chiral discrimination and quantitation.     

Gender justice,human rights and measurement in the mathematics classroom

In line with international trends, the new South African mathematics curriculum implores mathematics educators to realize a pedagogy in their classrooms that is more practical, activity-oriented, and connected to their learners' lives. Drawing on data from a larger study that explores theory–practice relations in mathematics education, this paper shows how such progressive practices, when interpreted with respect to the teaching of measurement which required learners to use different measuring instruments for measuring the school grounds in learning about length and perimeter, were found to be deeply gendered. In two different contexts of an ‘African' township school and a predominantly ‘Indian' suburban school, girls in a grade 6 mathematics classroom faced direct sexism as they struggled to take the opportunity to participate in the activity and learn how to measure – an important mathematical competence and everyday knowledge and skill. The article analyses the data with reference to the human rights imperatives of the new national curricula and approaches to addressing disadvantage and discrimination for girls in mathematics classrooms.     

Synthesis,growth and optical properties of semi organic non linear optical single crystal: l-Arginine acetate

In the recent past, nonlinear optical materials are getting attention in the field fibre optic communication and optical signal processing. In the present study, the title compound was successfully synthesized by conventional chemical reaction and then the single crystal was grown by slow evaporation solution growth technique. l-Arginine acetate (LAA) is semi organic non linear optical single crystal and crystallizes in noncentrosymmetric space group. The grown good quality single crystals have been analyzed by different characterization analyses such as powder X-ray diffraction, high resolution X-ray diffraction (HRXRD), Raman spectroscopy, photoluminescence, SEM, micro-hardness, thermal and birefringence analyses.     

One-pot synthesis of chalcone epoxides—A green chemistry strategy

Waste minimization is a very important aspect of an environmentally benign protocol. A one-pot consecutive process has been developed for chalcone epoxide synthesis that allows compounds to be prepared without having to isolate and purify the intermediates. The strategy utilizes consecutive Claisen Schmidt condensation and epoxidation reactions to prepare chalcone epoxides from substituted benzaldehydes and acetophenones in good yields.     

Investigation of the reactions of 2-hydrazino-benzimidazoles with β-diketones: Synthesis of 2-(3,5-disubstituted- 1H-pyrazol-1-yl)benzimidazoles

Reaction of 2-hydrazinobenzimidazoles with β-diketones in neutral and acidic media revealed that 2-(3,5-disubstituted-1H-pyrazol-1-yi)benzimidazoles are formed in the former case, whereas hydrazones are obtained in acidic medium. Further the alkylation of > NH of the title compound was investigated. Characterisation of these products have been done by elemental analysis, ir, pmr, ¹⁹F nmr, ¹³C nmr and mass spectral studies.