On the analytical solutions of unstable surface layer similarity equations

Summary An approximate relationship between the gradient, Ri, and the bulk Richardson number, Ri_b, for unstable atmospheric conditions, is suggested. The proposed relation shows much better agreement with the estimation provided by a numerical iterative method than the usual approximations suggested by Louis and Byun.     

Elastoplastic state of axisymmetrically loaded laminated bodies of revolution made of isotropic and orthotropic materials

Institute of Mechanics, Ukrainian Academy of Sciences, Kiev. Translated from Prikladnaya Mekhanika, Vol. 28, No. 1, pp. 31–39, January, 1992.     

Complex formation of vinylidene chloride with hydrogen chloride in the solid phase at low temperatures

Moscow State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 170–174, March–April, 1992.     

Radiochemical solvent extraction method for the determination of Cd and Hg using thionalide as a single reagent

A radiochemical solvent extraction method has been developed for the simultaneous determination of submicrogram amounts of Cd and Hg using^115mCd and²⁰³Hg tracers respectively and thionalide as a single complexing reagent. Hg was determined by 0.05% thionalide in ethyl methyl ketone (EMK) at pH 8.5, masking Cd with 0.1M KCN. From the aqueous phase Cd was demasked using formal-dehyde-acetic acid, pH adjusted to 9.5 and extracted into 0.05% thionalide in chloroform. The method is simple, fast and yields accurate results.     

Electrochemical reduction of 1,1-dihalo-2,2-disubstituted cyclopropanes

The electrochemical reduction of 1,1-dihalo-2-R-2-methylcyclopropanes was studied by polarography and preparative electrolysis. A mixture of stereoisomeric monoboro- and monochlorocyclopropanes was obtained with preparative yield of 60–70% in preparative electroreduction in methanol against a background of 0.1 M LiClO₄. In the case of bromine derivatives of cyclopropanes (except when R = CN) an effect was found on the part of the current density on the ratio of cis and trans isomers, which was interpreted as a change, in dependence on current density, of the contributions of the reactions of reduction of the starting compounds (S_N2 mechanism) and ionic pairs (S_N1 mechanism). The effect of the solvent (CHCl₃, DMF, DMSO, MeOH) and background salt (LiClO₄, Et₄NBr) on the ratio of stereoisomers is in agreement with this interpretation.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2023–2032, September, 1992.     

Complete assignment of the 1H and 13C NMR Spectra of 11,12-Dimethoxy[1]benzothieno[3,2-a]-4,7-phenanthroline and its 8-Chloro Analogue: Concerted Use of Two-Dimensional NMR Techniques

The ¹H and ¹³C nmr spectra of 11,12-dimethoxy[1]benzothieno[3,2-a]-4,7-phenanthroline and its 8-chloro precursor were totally assigned using a combination of two-dimensional nmr techniques. After correlation of the majority of the proton signals by a COSY spectrum and one-bond heteronuclear correlation, the full assignment of the ¹H and ¹³C nmr spectra of the novel heterocyclic compounds required the application of long-range CH coupling information particularly for quaternary carbon resonance assignments and the orientations of individual spin systems relative to one another. Key long-range heteronuclear couplings in both compounds served to confirm the one-bond heteronuclear correlations. Unequivocal interpretation of the spectral data leads to the complete assignments of the resonances.     

Parity violation at neutron p-wave resonances of238U and232Th and related questions

Parity violation effects have been studied at 40 neutron p-wave resonances of the even-even nuclei²³⁸U and²³²Th. Of these 11 show parity violation effects larger than 2 standard deviations, making parity violation a rather common phenomenon. Parity mixing up to 10% has been found. The root-mean squared matrix elements for parity violation derived from these resonances are M=0.58 (+0.50/-0.25) meV for²³⁸U, respectively 1.39 (+0.35/-0.38) meV for²³²Th.     

Selective catalytic hydrogenation of the pyridine ring in arylpyridines and condensed pyridine systems (review)

Data are summarized concerning selective hydrogenation of the pyridine ring in arylpyridines, including those containing silicon, and in annelated pyridines. An effective catalyst, rhenium heptasulfide, has been found, which makes it possible to reduce the pyridine ring without affecting the benzene rings.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1450, November, 1992.     

Extended transverse-momentum analysis for intermediate-energy heavy-ion collisions

An extension of the transverse-momentum analysis of Danielewicz and Odyniec is proposed. This extension involves a consideration of baryonic p_T-distribution widths in and out of the reaction plane. Calculations within one- and two-fluid mean-field models show that such an analysis allows us to extract more information on the nuclear equation of state and stopping power than the conventional one does. Different criteria for selecting collision events (i.e. sorting them out according to impact parameters) are also examined. Selections according to the baryonic multiplicity in the midrapidity region and the transversal-to-longitudinal energy ratio are found to be suitable for this purpose.     

Application of heat flow calorimetry to the study of oilwell cements

The majority of previous studies of the hydration of cements using heat flow calorimetry have been carried out isothermally. However, with oilwell cements the slurry is mixed on the surface at ambient temperature and then gradually increases in temperature as it is pumped down the well. A Setaram C-80 calorimeter has been used to simulate the temperature ramp in API oilwell cement test schedules. This approach has enabled cementing reactions to be studied for the first time under conditions approaching those encountered in the field, and has shown that the results obtained from isothermal experiments may be misleading.The permission of the British Petroleum Company PLC to publish this paper is gratefully acknowledged.