Studies in the separation and determination of zirconium using vanillin as an analytical reagent

Vanillin, quantitatively precipitates zirconium between pH 5·0–6·5, as insoluble complex. This complex on ignition gives ZrO₂ which can be weighed. Zirconium can be readily separated and determined in the presence of varying quantities of chromium (III), cobalt (II), copper (II), manganese (II), molybdenum (VI), nickel (II), titanium (IV), tungsten (VI), uranium (VI), vanadium (V), zinc (II) and trivalent rare earths.     

Studies onO-Vanillinoxime as an analytical reagent

o-Vanillinoxime has now been used for the gravimetric determination of copper and nickel alone and in presence of many foreign ions. Copper can be estimated in presence of appreciable amounts of cadmium, zinc, cobalt and lead. The interference due to iron (III), antimony (III), bismuth (III) and tin (II) can be removed by suitable masking agents. Determination of copper and nickel in presence of each other has also been carried out.     

Physico-chemical studies on the formation of some tungsto-tartrates and molybdo-tartrates

The viscosity, depression in freezing point, potentiometric and conductometric experiments on the reaction of tartaric acid with sodium tungstate and sodium molybdate indicated the formation of the complex at 1:1 ratio of tungstate or molybdate to tartaric acid. The complex compounds have been isolated. The silver, mercurous, copper, cadmium, zinc, mercuric, barium, strontium, lead, cobalt and nickel salts of tungstotartrate and molybdo-tartrate have been prepared from the sodium salt and their composition studied.     

Polarography of cobalt (II) in water and 50% methanol

The polarographic behaviour of cobalt (II) in water and 50% methanol in the presence of various supporting electrolytes has been studied. The kinetic parameters and activation energy for the electrode process have been evaluated and compared. The results have been discussed on the basis of selective hydration of cobaltous ion at the electrode surface.     

Isotopes of uranium and radium in Indian rivers

The concentrations of dissolved uranium and radium isotopes have been determined in the waters of several Indian rivers. The concentration of uranium (U-238) is found to vary between 0·01–7·0 micrograms/litre, depending primarily on the terrain through which the river flows. From the available data on the activity ratios, U-234/U-238, concentration of U-238 in rivers and the amount of uranium depositing on the ocean floor, a material balance calculation has been attempted. This shows that the supply of uranium to sea by rivers based on above measurements, is inadequate to explain the observed concentrations of U-238 and U-234 in the oceans. The Ra-226 concentration of river waters is found to be of the order of 0·1 dpm/litre (varying between 0·05–0·2 dpm/litre). The activity ratios, Ra-228/Ra-226, range between 1 and 4. This large variation is clearly related to the fact that the concentrations of the parent nuclides of Ra-226 and Ra-228 are different. The observed ratios are consistent with those expected from leaching of clays/soils; however, analogous to the situation in the case of uranium, the observed concentrations of radium isotopes in the oceans are too large to be explained by their influx by rivers.     

Spectrophotometric studies of uranium (VI)-pongamol complex

The spectrophotometric studies of uranium (VI)-pongamol complex have been carried out in 50% aqueous ethanolic solutions. Pongamol produces a yellow complex with an aqueous uranyl salt solution, the complex is soluble in 50% aqueous ethanol. The complex is quite stable for 24 hours, the optical density remaining constant at pH 5·6–7·1. The complex obeys Beer-Lambert’s law at 390 mµ in the concentration range of 1 to 5 p.p.m. of uranium in solution. The molar composition of the pongamol uranium (VI) complex has been found to be 2:1, and its tentative structure has been suggested. The cations and anions which interfere in the estimation of uranium using pongamol have been indicated.     

铀包装容器含水量计算分析

以铀材料腐蚀理论、Henry定律、渗透与泄漏理论为基础,建立了铀包装容器的含水量理论计算方法,分析了铀包装容器在不同状态下的水分含量及其变化规律.结果表明,水分的泄漏量、渗透量和泄漏渗透处两端的压力差成正比,渗透与材料本身的渗透系数有关;有机材料吸附水不仅与材料自身的饱和含水率有关,而且和有机材料所处的水分分压有关;铀水反应消耗水量与铀材料质量、表面积及时间成正比.水分的渗透、环境湿度及有机材料吸附水是影响铀包装容器中水分的主要因素.     

BIS-2-pyridyl glycol as a reagent for gravimetric determination of uranium,aluminium and beryllium

Bis-2-pyridyl glycol has been used for the gravimetric determination of uranium, aluminium and beryllium. The reagent quantitatively precipitates uranium from uranyl nitrate solution at pH 5.0–8.0, aluminium from potash alum solution at pH 5.2–8.5 and beryllium from beryllium sulphate solution at pH 7.5–9.5. The precipitate in each case is ignited to the corresponding oxide and weighed.     

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.     

Geochemistry of boron in the ultrabasics of Nuggihalli schist belt,Karnatak state,India

Contents of boron (ppm), magnesia (%) and silica (%) of thirty samples of basic and ultrabasic rocks and 8 samples of serpentinites from Nuggihalli schist belt have been determined by spectrochemical, E.D.T.A. and colorimetric methods respectively. From the analytical data it is found that boron in serpentinites and ultrabasic rocks has higher clarks. The increase of boron in serpentinites and ultrabasic rocks is suggestive of allometamorphism. From the geochemical and statistical investigations it appears that there exists a correlation between the content of boron and magnesia in the basic and ultrabasic rocks and in serpentinites. Boron content in brown serpentinite is less than in platy serpentinite.     

A polarographic study of methionine complexes of nickel and cobalt

A polarographic study of nickel and cobalt complexes of methionine has been carried out. In sodium perchlorate and tetramethyl-ammonium bromide (TMAB) media, catalytic hydrogen waves were observed owing to the lowering of hydrogen overvoltage on mercury by the adsorption of these complexes on the dropping electrode. The presence of tetrabutylammonium ion inhibits the catalytic activity.     

Kinetics of oxidation of thiohydantoin and rhodanine with vanadium (V)

The oxidation of thiohydantoin and rhodanine by quinquivalent vanadium ion is first order with respect to both vanadium ion and the organic substrate. The rate of oxidation increases with increase in concentration of hydrogen ions. The energy, entropy and free energy of activation have been evaluated. Formation of an intermediate complex between the organic substrate and vanadium (V) is not indicated by kinetic evidence. Some possible steps in the reaction have been proposed.     

X-Ray K-absorption edges of cobalt in two recently prepared chelates

K-absorption edges of cobalt in two chelates,viz., Co (II) bis S-ethyl 1-amidino 2-thiourea and Co (III) isonitroso acetylacetonate have been recorded photographically. The results have been discussed in the light of available magnetic measurements and favour a tetragonal structure for the first and an octahedral one for the second chelate.     

U234/U238 activity ratios in South Pacific Ocean waters

Analyses of uranium extracted from South Pacific waters by thein-situ extraction method point to a uniform depth independent value of 1·14 ±0 02 for the U²³⁴/U²³⁸ activity ratio. This value is also the same, within one standard deviation, as that determined for the N. Pacific, S. Indian and Atlantic waters.     

Rayleigh wave scattering due to a rigid barrier in a liquid halfspace

The paper presents a theoretical formulation for studying scattering of Rayleigh waves due to the presence of rigid barriers in oceanic waters. The Wiener-Hopf technique has been employed to solve the problem. Exact solution has been obtained in terms of Fourier integrals whose evaluation gives the reflected, transmitted and scattered waves. The scattered waves have the behaviour of cylindrical waves originating at the edge of the barrier. Numerical results for the amplitude of the scattered waves have been obtained for small depth of the barrier.     

Discovering oxygen channel topology in photosystem II using implicit ligand sampling and wavefront propagation

Photosystem II (PSII) of photosynthesis uses water as substrate for its photochemical reaction. Molecular oxygen is one of the products of this complex reaction which uses the energy of light to oxidize water and reduce plastoquinone. The active site of PSII is buried deep within the protein, which raises the question of whether there are specific access channels guiding substrate water to the site of catalysis and product oxygen away from it. Substrate/product channels have been proposed to exist and serve various functions in PSII, however the preferred paths have not been unambiguously identified. We investigated oxygen transport between the active site of PSII and the solvent. For this purpose, we have applied molecular dynamics simulations followed by implicit ligand sampling. We then found minimal cost pathways for the oxygen through the protein and obtained topology maps of the oxygen-accessible part of a chemical labyrinth. Application of this new strategy led to identification of two oxygen channels in the protein. Both channels connect the protein surface with region of high oxygen affinity near the active site.     

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.     

Substitution of coordinated chlorides in cis-α and cis-β dichloro (triethylene tetramine) cobalt(III) chloride [Co(trien)Cl2]Cl by thiocyanate in aqueous medium

Substitution of coordinated chlorides in cis-α, and cis-β dichloro (triethylene tetramine) cobalt(III) chloride by thiocyanate was studied in aqueous medium in the pH range 3.8 to 4.0 at 25–26° C. Substitution, as in aquation, took place in two steps corresponding to the two chlorides, one step being faster than the other. Mechanisms have been discussed in the paper.     

Investigation of the squeezing out of the current in some flows in coastal water-bearing layers

Mathematical models of certain flows of fresh ground waters, in a semi-infinite pressurized water-bearing layer, to a salt water sea (basin, reservoir, pot hole, etc.), above the surface of which there is a layer of fresh water, are considered within the framework of the two-dimensional theory of steady seepage. To investigate them, mixed boundary-value problems in the theory of analytic functions are formulated and solved using Polubarinova-Kochina's method. On the basis of these models, algorithms are developed for calculating the squeezing out (that is, the process of the forcing out of the seeping fresh waters by the heavier salt waters, leading to deformation of the interface of the liquids) in cases when the ground water flows enter the sea from the side and from below. A detailed analysis of the structure and characteristic features of the processes, as well as of the effect of all the physical characteristics of the models on the nature and degree of the squeezing out of the fresh water, is carried out using the exact analytical relations obtained as well as numerical calculations. In the special case when there is no layer of fresh water above the surface of the sea, a comparison of the results of the calculation is given for both inflow schemes, and the nature of the dependences of the degree of squeezing out of the water from the initial position of contact of the liquids is discussed.     

X-ray spectroscopic study of chemical bonding in NiSe and NiSe2

The K absorption spectra of nickel and selenium have been recorded photographically in the pure metals and the compounds NiSe and NiSe₂. It has been observed that the Ni discontinuity shifts toward the high energy side with respect to that in the pure metal by about 5.0 eV for NiSe and about 6.7 eV for NiSe₂. The Se edge in both these compounds is found to shift by about 2.6 eV toward the low energy side with respect to that in pure selenium. From these results it is possible to obtain the bonding pictures for the compounds. The compound NiSe appears to have resonating p³ type of bonding. For NiSe₂ the orbitals involved in the bonding are d²sp³ for the metal atom and sp³ for the metalloid atom. The electrical behaviour of the compounds has been explained on the basis of these bonding pictures.