Polarography of potassium ethylxanthate,a titrant in amperometry

Polarograpbic studies of potassium ethylxanthate (RSH or xantbate) at the dropping mercury electrode (DME) reveal that the product of the anodic reaction is strongly adsorbed at the mercury drop as indicated by a prewave. The adsorbed film (0·15 mM to 1·0 mM xanthate solution) greatly affects the characteristics of the anodic wave of xanthate in aqueous medium. The current of main wave is proportional to the concentration of xanthate up to 2·5 mM in aqueous medium at DME. This electrode is used as an indicator electrode for amperometric titrations of metal ions with xanthate. Proper buffer composition and pH are developed for the accurate determination of metal ions. The combined use of the cathodic current of metal ions and the anodic current of xanthate under controlled pH conditions makes possible the amperometric titration of two metal ions in a mixture.     

Volumetric determination of copper by precipitation with ammonium thiocyanate

Potassium dichromate was employed for the determination of copper by precipitation as cuprous thiocyanate. 1·0–10·0 mg of copper was accurately determined by this procedure. The method was applied for the analysis of copper in Devarda’s alloy and chalcopyrites.     

2-Hydroxy-1-acetonaphthoneoxime as analytical reagent

2-Hydroxy-1-acetonaphthoneoxime has now been proposed as a new reagent for the gravimetric determination of copper. Copper in the range 4·0 to 40·0 mg can be accurately determined by this procedure. The interference of the elements usually associated in its alloys and ores is also studied. The method is applied in the analysis of brass and chalcopyrite.     

Spectrophotometric investigation of beryllium-2-hydroxy chalcone complex

2′-Hydroxy chalcone gave an intense orange-yellow color with beryllium in the pH range 5·5–6·2. The limits of identification and dilution were 0·125γ and 1:4 × 10⁵ respectively. A detailed spectro-photometric investigation of the color reaction was carried out. The complex obeyed Beer’s Law in the concentration range of 0·5–6·0p.p.m. at 460 nm. In the complex the ratio of metal to ligand is 1:2. The instability constant of the complex was 2·176 × 10^?6 at 28°. Oxalate, tartrate, citrate and fluoride interfered. The tolerance limits of iron, aluminium, chromium, uranium, thorium and vanadium are reported.     

Chalcones as inorganic analytical reagents

1·0–6·0 p.p.m. of germanium could be estimated spectrophoto-metrically with 2′, 3′, 4′-trihydroxy chalcone as reagent at pH 5·8–6·0. The complex was shown to contain three gram-moles of the reagent to one gram-atom of germanium both by Job’s method of continuous variations and the slope ratio method of Harvey and Manning. The instability constant was determined by the method of Edmonds and Birnbaum and found to be 1·670×10^?11 at 28° C. It is concluded that complex formation involved only the two ortho hydroxyls in each molecule of the reagent and the carbonyl group played no part.     

He3 nuclei in the low energy primary cosmic radiation

The flux of He³ nuclei and the ratio He³/(He³+He⁴) in the low energy primary cosmic radiation have been determined using a stack of nuclear emulsions exposed at 3·1 g. cm.^?2 of atmospheric depth from Fort Churchill, Canada, in June 1963. The grain-densityversus residual range method was used to determine the masses of the helium nuclei. Using a sample of 146 helium nuclei whose masses could be identified, the ratio He³/(He³+He⁴) is obtained as 0·14±0·04 for the kinetic energy interval 115–210 MeV per nucleon and 0·43±0·11 for the rigidity interval 0·85–1·05 BV. The differential fluxes of He³ nuclei are determined as 0·017±0·006, 0·045±0·015, and 0·054±0·017 particles/M². Sr. Sec. MeV/nucleon, in the kinetic energy intervals of 117–183, 183–217, and 217–250 MeV/nucleon respectively. These results are compared with those of other investigators. From the results of the present work the amount of matter traversed in space by the primary cosmic ray helium nuclei of energy 115–210 MeV/nucleon is obtained as 4·7±1·8 gm. cm.^?2 of hydrogen.     

The new physiology of vision

α-Nitroso-β-naphthol was successfully employed for the gravimetric determination of Mercury (ii) (as nitrate) and in its separation from copper (ii). The former was percipitated at pH 1·9 and the latter at pH 11·00. The precipitate could be dried to constant weight at 110° C. The composition of the complex was established by analysis to be Hg (C₁₀H₆NO₂)₂ 20 mg. of mercury could be estimated with an error of ± 0·3% in pure solutions. Appreciable amounts of copper could be removed in alkaline medium without co-precipitation of mercury. The error was ±0·5%.     

Determination of cadmium by precipitation of cadmium molybdate from homogeneous solution

A quantitative method has been developed for the determination of cadmium as cadmium molybdate by PFHS method using the technique of volatalisation of ammonia. The pH range for complete precipitation is found to be 6·0–7·6. Presence of 20–50 mmoles acetate is necessary for obtaining quantitative results. From 20–200 mg of cadmium could be conveniently determined using this method. Zinc, magnesium and nickel do not interfere. The anions such as sulphate, acetate, nitrate and chloride can be tolerated up to 50 mmoles. The precipitate has constant weight upto 750°.     

Spins of the first two excited states in27Mg by an angular correlation technique in the reaction26Mg (d,pγ)27Mg

Proton-gamma-ray angular correlation measurements, employing the ‘method II’ of Litherland and Ferguson, have been made in the reaction²⁶Mg (d, pγ)²⁷Mg, using 1·80 MeV deuteron beam and detecting the outgoing protons at 0° with respect to the beam. Analysis of these measurements leads to spin assignments of 3/2 and 5/2 for the 0·98 and 1·69 MeV excited states of²⁷Mg. The 1·69 MeV second excited state is found to decay almost completely to the ground state.     

Complex formation between cadmium and thiosalicylic acid

Polarographic measurements on the system Cd-thiosalicylic acid (TSA) reveal the formation of a complex, 1:2:: metal: ligand (ammonia buffer pH 9·1,µ=0·2 M, 50% alcoholic medium), dissociation constant of the complex being 6·3 × 10^?8 at 30° C. Potentiometric titrations confirmed this stoichiometry, stepwise stability constants, logk ₁ and logk ₂ being 7·85 and 8·10 respectively. The complex has also been isolated and studied in solid state.     

Spectrophotometric studies of copper (II)—bis-2-pyridyl glycol complex

An aqueous solution ofbis-2-pyridyl glycol forms a deep blue water-soluble complex with an aqueous solution of copper (II) salts. The complex has an absorption maximum at 600–650 mµ between pH range 3·0–8·7. The complex is stable for four days and obeys Lambert-Beer’s law in the concentration range of 5·08–50·80 ppm. of copper (II) in solution. The optical density of the complex remains constant between pH 3·8–5·9. The molar composition as determined by the method of continuous variation and by the slope ratio method has been found to be 1:1. The limits of interference due to some foreign ions during the estimation of copper (II) have been determined.     

SL(3,3~n)和SU(3,3~n)的第一Cartan不变量

确定Cartan不变量是代数群与相关的李型有限群的模表示理论中的一个重要方面.作者利用代数群模表示理论中的一系列结果,计算了3~n个元素的有限域上特殊线性群SL(3,3~n)和特殊酉群SU(3,3~n)的第一Cartan不变量,得到如下结论:当G=SL(3,3~n)时,C_(00)~((n))=a~n+b~n+6~n-2·8~n;而当G=SU(3,3~n)时,C_(00)~((n))=a~n+b~n+6~n-2·8~n+2·(1+(-1)~n),其中a,b是多项式x~2-20x+48的两个根.另外,作者也得到了射影不可分解模U_n(0,0)的维数公式:dim U_n(0,0)=(12~n-6~n+∈)·3~(3n),其中,当G=SL(3,3~n)时,∈=1;而当G=SU(3,3~n)时,∈=-1.     

Determination of lead by the precipitation of lead molybdate from a homogeneous solution by the diffusion method

A satisfactory quantitative method for the determination of lead as lead molybdate by precipitation from a homogeneous solution has been developed. The method employs the diffusion of ammonia into a solution containing lead and sodium molybdate in nitric acid medium. The precipitation of lead in the range of 28·0–280·0 mg is complete within 8–9 hours. Anions like sulphate, arsenate, phosphate, tungstate and chromate in moderate concentrations and cations such as Zn (II), Cu (II), Ni (II), Co (II), Mn (II), Cd (II), Hg (II), Ag (I), Ti (IV), As (V), Mg (II) and Al (III) do not contaminate the precipitate. The precipitate gets constant weight at 120°. This eliminated the ignition of the precipitate,i.e., the contamination of molybdic oxide by the precipitate was reduced.     

Numerical studies of slow viscous rotating fluid past a sphere

Navier-Stokes equations for steady, viscous rotating fluid, rotating about the zaxis with angular velocity ω are linearized using Stokes approximation. The linearized Navier-Stokes equations governing the axisymmetric flow can be written as three coupled partial differential equations for the stream function, vorticity and rotational velocity component. Only one parameterR _eω =2ωa ²/v enters the resulting equations. Even the linearized equations are difficult to solve analytically and the method of matched asymptotic expansions is to be applied. Central differences are applied to the two-dimensional partial differential equations and are solved by the Peaceman-Rachford ADI method. The resulting algebraic equations are solved by successive over relaxation method. Streamlines are plotted for Ψ=0·01, 0·05, and 0·25 andR _eω =0·1, 0·3, 0·5.     

A polarographic study of methionine complexes of cadmium and indium

The stability constants of methionine complexes of cadmium were determined polarographically by ths method of DeFord and Hume as β₁ =6·5 × 10³, β₂ = 1·7 × 10⁶ and β₃ = 2·1 · 10⁸. The indium complexes were studied by the modified method of Momoki and Ogawa and two complexes, with β₁ = 1·7 × 10⁸ and β₂ = 8·4 × 10¹³, were identified in the concentration range studied. The haf-wave potential of uncomplexed indium ion which cannot be measured directly owing to the irreversible nature of the reduction was calculated as — 0·503 Vvs. SCE.     

Investigations on the multiply charged nuclei of the primary cosmic radiation near the geomagnetic equator using nuclear emulsion

A nuclear emulsion stack was exposed over Hyderabad, India (geomagnetic latitudeλ=7·6° N) under a mean atmospheric depth of 6·8 g./cm.², on 24 March 1960. The relative and absolute intensities of Be and B nuclei and nuclei of charge Z?6 (the S-nuclei) have been determined in this stack. The intensities were extrapolated to the top of the atmosphere using measured fragmentation parameters involved in collisions of cosmic ray nuclei in graphite. The flux values of Be, B and S nuclei at the top of the atmosphere have been determined to be 0·025±0·011, 0·101±0·023 and 1·12±0·10 particles/m.² sec. sr. respectively. The ratios of intensities B/S, Be/S and Be/B have been found to be 0·09±0·02, 0·022±0·008 and 0·25±0·11 respectively. These ratios of intensities have been used (a) to compute the amount of matter traversed by the radiation before reaching the vicinity of the earth as 2·6±0·6 g./cm.², (b) to show that the Fermi mechanism of acceleration of particles is not efficient at these energies (1–10 GeV/n.) in interstellar space and (c) to show that preferential acceleration of H₁-nuclei (Z?20) is not of overwhelming importance. The derived source composition of nuclei of energy ?7·5 GeV/n suggests that N, O, F and H₃-nuclei (Z=10–15) have similar abundances in the universe and in cosmic rays, and that C and H₁-nuclei are overabundant in cosmic rays.     

Microwave spectrum of pentafluorobenzonitrile

The absorption spectrum of pentafluorobenzonitrile has been investigated in the frequency range of 18–26·5 GHz using a 100 KHz stark modulated microwave spectrometer. The analysis of the spectrum is based on the rigid asymmetric rotor theory. The rotational constants obtained are A=1026·82±0·3 MHz, B=776·34±0·1 MHz, C=442·06±0·1 MHz and the asymmetry parameterχ=+0·1433. The inertial defect is I _o ?I _a ?I _b =0·081 amu Ų. The bond distances ared _CF=1·328 Å andd _CN=1·157 Å. The results are in good agreement with the assumed planarity of the molecule and the normal values of bond distances.     

Periodicities in the series of cyclonic disturbances over India

The time series of yearly occurrence frequency of cyclonic disturbances over the Indian region for 1891–1970 is subjected to power spectrum analysis by the maximum entropy method (MEM) of Burg. Earlier analyses by the conventional Blackman-Tukey method had indicated periodicities atT= 2·3-2·5, 5 and 30–45 years at about 90–95% significance level. The present analysis shows peaks atT = 1·2, 2·4, 2·9, 3·7, 4·7, 6·4, 7·4, 9·2, 10·5, 20 and 40–60 years but the significance level may not be better than the earlier method. When data are analysed separately for first half and latter half, periodicities observed are quite different, the earlier half revealingT= 1· 2, 2·3, 2·9, 4·7, 9·0 and 23 years and the latter half revealingT= 1·2, 2·1, 2·4, 3·8, 6·7 and 21 years. Thus, a change of pattern before and after about 1920 is indicated. However, the power in the various peaks is small and a random origin cannot be ruled out. An analysis of several artificially produced samples of pseudo-Gaussian random white noise of the same mean, standard deviation and length (80 values) as the above physical samples indicated that similar peaks could occur by pure chance also. Physically, T=l·2 years corresponds to the Chandler’s wobble and other peaks could be harmonics of the sunspot cycleT= 11 years or double sunspot cycleT = 22 years. However, no peak is noticed at or nearT= 11 years whereasT near 22 years is noticed.     

Estimation of the quality of adhesion of a metallic coating to a polymer film using the scratch method

A method of determining the quality of adhesion of a metallic coating to a polymer film at coating thicknesses of 1000–3000 Å and film thicknesses of 10–100 µ using the scratch method is described. The results of testing various aluminized polyethylene terephthalate and polyethylene film specimens, differing with respect to the treatment of the polymer surface before deposition of the metal, are presented. The aluminization vacuum was 5 · 10^?4 or 9 · 10^?3 mm Hg.     

Semisummands and semiideals in banach spaces

Let |·| be a fixed absolute norm onR ². We introduce semi-|·|-summands (resp. |·|-summands) as a natural extension of semi-L-summands (resp.L-summands). We prove that the following statements are equivalent. (i) Every semi-|·|-summand is a |·|-summand, (ii) (1, 0) is not a vertex of the closed unit ball ofR ² with the norm |·|. In particular semi-L ^p-summands areL ^p-summands whenever 1<p≦∞. The concept of semi-|·|-ideal (resp. |·|-ideal) is introduced in order to extend the one of semi-M-ideal (resp.M-ideal). The following statements are shown to be equivalent. (i) Every semi-|·|-ideal is a |·|-ideal, (ii) every |·|-ideal is a |·|-summand, (iii) (0, 1) is an extreme point of the closed unit ball ofR ² with the norm |·|. From semi-|·|-ideals we define semi-|·|-idealoids in the same way as semi-|·|-ideals arise from semi-|·|-summands. Proper semi-|·|-idealoids are those which are neither semi-|·|-summands nor semi-|·|-ideals. We prove that there is a proper semi-|·|-idealoid if and only if (1, 0) is a vertex and (0, 1) is not an extreme point of the closed unit ball ofR ² with the norm |·|. So there are no proper semi-L ^p-idealoids. The paper concludes by showing thatw*-closed semi-|·|-idealoids in a dual Banach space are semi-|·|-summands, so no new concept appears by predualization of semi-|·|-idealoids.