A new class of interior solutions for a stress-energy tensor of Segré characteristic [111, 1]

The interior solutions of (the tetrad versions of) Einstein's field equations withT _AB having Segré characteristic [111, 1] (which has all four eigenvalues distinct), are investigated. For this purpose amixed method, which combines Synge'sg method andT method, is introduced. Some of the tetrad equations are solved for the metric functions while the remaining equations are used to define the corresponding components ofT _AB . As necessary conditions of the consistency of the mixed method the conservation equationsT ^AB _B =0 are explicitly verified. Several simplifications and analysis of some differential inequalities show the existence of a new class of solutions which, in addition to having Segré characteristic [111, 1], also satisfy the strong energy conditions of Hawking and Ellis.This Author is a member of the Theoretical Sciences Institute, Simon Fraser University, Burnaby, B.C., V5A 1S6, Canada.     

A new cytokinin from the fruits of zantedeschiaaethiopica

A new purine derivative with cytokinin activity was isolated from the cuckoo-pint fruits ($\text{Zantedeschia}$$\text{aethiopica}$) and identified as 6-(o-hydroxybenzylamino)-2-methylthio-9-β-D-glucofuranosylpurine $\text{1}$.     

Interaction of acridine orange monohydrochloride dye with sodiumdodecylsulfate, (SDS) cetyltrimethylammoniumbromide (CTAB) and p-tert-octylphenoxypolyoxy ethanol (Triton X 100) surfactants

Summary Results of spectrophotometric, conductometric and dialysis studies on the interaction of acridine orange monohydrochloride dye with sodiumdodecylsulfate (anionic), cetyltrimethylammoniumbromide (cationic) and Triton X 100 (nonionic) surfactants have been reported. The anionic surfactant, SDS has been observed to undergo both electrostatic and hydrophobic interactions with the dye cation. Aggregation of the dye molecules can be destroyed when the surfactant is in large excess, whereas, excess dye can check micellization of SD S. At a ratio of AO:SDS=1:7 and above, dye embedded mixed micelles are formed. These remain in a separate phase, probably as coacervates. At lower ratios than 1:7, aggregation of dye molecules is induced, which being complexed with SDS become stabilized as colloids. The colloid and the coacervate have been observed to be thermally stable, negatively charged materials that can be broken by salts, and cations of higher valency are more effective in this regard. An 1:3 = AO:SDS colloid has beeen found to be sufficiently large like the coacervates to pass through a membrane having cut off permeability for molecular weights 12,000 and above. All the above features of AO-SDS interaction have been observed to be absent for AO-CTAB and AO-TX 100 systems, Even hydrophobic interaction has played an insignificant role in these cases. Thus, the dye cation, the cationic and the nonionic surfactants have almost retained their self physicochemical identities in solution in the presence of each other. Electrostatic interaction is thus the primary requirement for acridine orange-surfactant (anionic) system; the hydrophobic effect is secondary and may become co-operative.With 9 figures and 2 tables     

Studies on ion association. Calorimetric study of the formation of monoazido complexes of Ni(II), Zn(II) and Cd(II)

From rehydration experiments the hydrates Ba(OH)₂ · 8 H₂O, Ba(OH)₂ · 3 H₂O β-Ba(OH)₂, · 1 H₂O, and γ-Ba(OH)₂ · 1 H₂O have been found in the system Ba(OH)₂-H₂O. Thermoanalytical measurements (DTA, TG, DTG, high temperature X-ray diffraction, high temperature Raman scattering) on these hydrates are reported. Thermal decomposition of Ba(OH)₂ · 8 H₂O and Ba(OH)₂ · 3 H₂O always results in the formation of β-Ba(OH)₂ · 1 H₂O, the stable form of the monohydrates at ambient temperature. Dehydration of β- and γ-Ba(OH)₂ · 1 H₂O, both of which form anhydrous β-Ba(OH)₂ as the first product of decomposition, starts at 105 and 115°C, respectively. Single crystals of Ba(OH)₂ · 3 H₂O and γ-Ba(OH)₂ · 1 H₂O were prepared from Ba(OH)₂ · 8 H₂O meltings and from ethanolic solutions of Ba(OH)₂ , respectively. The crystal data are: Ba(OH)₂ · 3 H₂O (orthorhombic, Pnma): a = 764.0(2), b = 1140,3(5), c = 596.5(1) pm, Z = 4; γ-Ba(OH)₂ · 1 H₂O (monoclinic, P2₁/m or P2₁): a = 704.9(2), b = 418.4(1), c = 633.3(1) pm, β = 111.45(2)°, Z = 2.     

The determination of molybdenum and tungsten in sea and surface water

A simple method for the determination of molybdenum and tungsten in sea and surface water is presented. Molybdenum and tungsten are concentrated on activated charcoal by adsorption as the ammonium pyrrolidine dithiocarbamate complex; the optimal pH for adsorption is 1.3. Mo and W are then determined by thermal neutron activation, forming ⁹⁹Mo (T_{$\text{1}\text{2}$} = 66.7 h) and ¹³⁷W (T_{$\text{1}\text{2}$} = 23.8 h), respectively. The ^99mTc daughter of ⁹⁹Mo is measured as soon as the equilibrium between ^99mTc(T_{$\text{1}\text{2}$}= 6 h) and ⁹⁹Mo is established. The detection limits are 0.05 μg Mo l^-1 and 0.05 μg W l^-1 (or 0.001 μg W l^-1 after a simple chemical separation).     

A carbazole-based polymeric azodye

A new polymeric azodye has been synthesized from carbazole by diazotization of its derivative N-methylcarbazole-3,6-diamine and subsequent coupling reaction with 2,2-bis(4-hydroxyphenyl-3-sulfonate-Na)-propane prepared from bisphenol-A. Its physico-chemical, electrical, and thermal properties have been characterized; finally, its application to the preparation of colored semiconductive films from polyvinyl alcohol has been studied.     

Acidic peroxo salts. A new class of initiators for vinyl polymerization. I. Kinetics of polymerization of acrylonitrile initiated by potassium monopersulfate catalyzed by Ag(I)

The kinetics of polymerization of acrylonitrile initiated by KHSO₅ and catalyzed by Ag(I) have been investigated in an aqueous medium over the temperature range of 35–50°C. The rates of polymerization R_p have been calculated and studied with respect to monomer and initiator. The catalytic activity of various metal ions on the initiator has been determined from a comparison of R_p values. The effects of monomer, catalyst, neutral salts, various amines, and inhibitor (hydroquinone) on the initial rate as well as maximum conversion have been studied. From the kinetics results a suitable reaction scheme has been proposed.     

Separation of molybdenum from tungsten with di(2-ethylhexyl)-phosphoric acid ac extractant

The use of di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant for the separation of molybdenum from tungsten was examined with the help of molybdenum-99 and tungsten-187 as radiotracers. Effective separation was obtained when the aqueous phase contained phosphoric acid at pH 0.8–2 or pH 3–3.5, depending on the amounts of metal. The method is applicable to both tracer and milligram amounts of molybdenum. The structure of the extracted species was examined by infrared spectroscopy.     

Doubly excited3Se,3De and3Ge states of two-electron atomic systems

Summary Time-dependent perturbation theory has been applied to calculate the doubly excited triplet statesNsns:³S^e,Npnp:³D^e andNdnd:³G^e (N=2, 3, 4,n=N+1, ... ,5) for He, Li⁺, Be²⁺ and B³⁺. A time-dependent harmonic perturbation causes simulataneous excitation of both the electrons with a change of spin state. The doubly excited energy levels have been identified as the poles of an appropriately constructed linearized variational functional with respect to the driving frequency. In addition to the transition energies, effective quantum numbers of these doubly excited states have been calculated and analytic representations of their wave functions are obtained. These are utilized to estimate the Coulomb repulsion term for these states which checks the consistency of the wave functions. These wave functions may also be used for calculating other physical properties of the systems.     

Studies on the exchange characteristics of [Co(NH3)6]3+ in amberlite IRC-50

Summary The exchange of Co(NH₃)₆]³⁺-ions on amberlite IRC-50 resin has been studied at room temperature. For this exchange process the cations are effective in the order: Cs⁺<Rb⁺<K⁺<Na⁺<Li⁺<NH₄ ⁺<Mg²⁺ <Ca²⁺<H⁺ and (C₂H₅)₄N<(CH₃)₄N⁺ ≪Cetyltrimethylammonium-ion <Cetylpyridinium-ion. The logarithm of the selectivity coefficient gives linear graphs when plotted against the radius of the hydrated ions or the reciprocals of theDebye-Hückel parameter?.