Foliations with persistent singularities

Let ω be a differential q-form defining a foliation of codimension q in a projective variety. In this article we study the singular locus of ω in various settings. We relate a certain type of singularities, which we name persistent, with the unfoldings of ω, generalizing previous work done on foliations of codimension 1 in projective space. We also relate the absence of persistent singularities with the existence of a connection in the sheaf of 1-forms defining the foliation.     

Structural and optoelectronic properties of antimony tin sulphide thin films deposited by thermal evaporation techniques

Thin films of SnSb₂S₄ have been prepared on glass substrate by using thermal evaporation techniques. The films were annealed in argon gas at low pressure in sealed glass ampoules at 85 °C, 150 °C, 275 °C and 325 °C. XRD of the films reveal that the low temperature annealed films are poly crystalline while the as deposited films and high annealed films are in amorphous states. There is no adequate variation in the photoconductivity response of the amorphous and crystalline phases. The transmittance of the films is low and having no transmittance below 740 nm. The band gap calculated by ellipsometry technique is in the range of 1.82–3.1 eV. The films have n-type conductivity but the film annealed at 325 °C show p-type conductivity.     

Determination of nitrate with a flow-injection system combining square-wave polarographic detection with on-line deaeration

The combination of a flow-injection system with square-wave polarography and on-line deaeration is applied to the determination of nitrate, utilizing the catalytic reaction between nitrate and uranyl ion. The method is simple, rapid (60 samples h^?1), sensitive and accurate, with a detection limit of 2 μM nitrate. The method has been applied to the determination of nitrate in drinking and river waters.     

Homotopy Solution for the Channel Flow of a Third Grade Fluid

The solution for the flow of a third grade fluid bounded by two parallel porous plates is given using homotopy analysis method (HAM). A comparison is made with the exact numerical solution for the various values of the physical parameters. It is found that a proper choice of the auxiliary parameter occurring in HAM solution gives very close results.     

Economic considerations important in the scale-up of an ovalbumin separation from hen egg-white on the anion-exchange cellulose DE92.

The scale-up of the separation of hen egg-white proteins has been investigated using Whatman DE92 anion-exchange cellulose. Having developed suitable chromatographic conditions, a maximum binding capacity of 100 mg protein/ml packed DE92 was determined in a 25-ml column. The process was scaled up 1000-fold and the influence of batch and column techniques on the chromatographic step assessed. Data indicate column processes to be more efficient than batch in the adsorptive stage.     

Spin-dependent sum rule for high-energy neutrino reactions

We present a sum rule which related the inclusive cross section for high-energy neutrino scattering on polarized proton targets to the axial-vector coupling constant. The derivation of the sum rule rests on the equal-time algebra of the time-components of the weak currents. The sum rule also provides a discriminatory test of unified models of weak and electromagnetic interactions based on spontaneously-broken gauge symmetry.     

Measurement of the mass of110Pd and114Pd using the (14C,16O) reaction

A measurement of the mass excess of¹¹⁰Pd and¹¹⁴Pd has been made by detecting emergent¹⁶O ions in aQ3D magnetic spectrometer using the¹¹²Cd(¹⁴C,¹⁶O)¹¹⁰Pd and¹¹⁶Cd(¹⁴C,¹⁶O)¹¹⁴Pd reactions at 60 MeV. The results are compared with theoretical predictions.     

Lead dioxide-coated carbon paste electrodes

Lead dioxide electrodeposited under optimized conditions on carbon paste provides an electroanalytically useful electrode, with an anodic working range extending to 1.9 V. Voltammograms for sulphite are used to study electrode lifetime and reproducibility; calibration graphs are linear up to 10^-3M sulphite in 0.5 M sulphuric acid.