Fatigue strength of metallic and composite materials under repeated high-cycle bending

The problem of fatigue strength analysis of metallic and composite materials subjected to combined static and cyclic bending is resolved. The analysis is based on limit-state models, which allow describing limiting-stress curves of all known shapes, including convex, rectilinear, S-shaped, and concave. The fatigue strength of the following materials is evaluated: carbon and alloyed steels, aluminum alloys, unidirectional organic plastics, laminated plastics, and glassfiber-reinforced plastics. The calculated and experimental data are in satisfactory agreement __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 26–36, May 2006.     

Novel K/Mn phosphate hydrates,K2Mn3(H2O)2[P2O7]2 and KMn(H2O)2[Al2(PO4)3]: hydrothermal synthesis and crystal chemistry

Two novel K/Mn phosphate hydrates, namely, dipotassium trimanganese dipyrophosphate dihydrate, K₂Mn₃(H₂O)₂[P₂O₇]₂, (I), and potassium manganese dialuminium triphosphate dihydrate, KMn(H₂O)₂[Al₂(PO₄)₃], (II), were obtained in the form of single crystals during a single hydrothermal synthesis experiment. Their crystal structures were studied by X‐ray diffraction. Both new compounds are members of the morphotropic series of phosphates with the following formulae: A₂M₃(H₂O)₂[P₂O₇]₂, where A = K, NH₄, Rb or Na and M = Mn, Fe, Co or Ni, and AM²⁺(H₂O)₂[M³⁺₂(PO₄)₃], where A = Cs, Rb, K, NH₄ or (H₃O); M²⁺ = Mn, Fe, Co or Ni; and M³⁺ = Al, Ga or Fe. A detailed crystal chemical analysis revealed correlations between the unit‐cell parameters of the members of the series, their structural features and the sizes of the cations. It has been shown that a mixed type anionic framework is formed in (II) by aluminophosphate [(AlO₂)₂(PO₄)₂]_∞ layers, with a cationic topology similar to the Si/Al‐topology of the crystal structures of feldspars. A study of the magnetic susceptibility of (II) demonstrates a paramagnetic behaviour of the compound.     

Proton magnetic resonance spectra of homoannular ferrocenes

The proton magnetic resonance spectra of homannular isomeric diethyl- and diacetyl-ferrocenes were studied. Chemical shifts were determined, and the results are discussed in terms of inductive and hyperconjugative effects of the substituent groups.     

Reaction of bromoform and iodoform with acrylic monomers initiated by Fe(CO)5+DMF

Conclusions The Fe(CO)₅ + DMF system, in contrast to peroxide initiation, permits us to carry out the addition of bromoform with selective cleavage of the C-Br bond to readily polymerizing acrylonitrile, methyl acrylate, and methyl methacrylate. Iodoform was shown to be significantly more active than bromoform in these reactions, which permits carrying out the radical addition and telomerization of iodoform in bromoform at lower temperature than without solvent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1904–1906, August, 1987.     

Investigation of the magnetic anisotropy of yttrium-samarium ferrogarnets

The temperature dependence of the cubic and induced anisotropies of singlecrystal garnets Y_3–xSm_xFe₅O₁₂ (x = 0.2, 0.3, 1.1, 1.8) is studied by the method of ferromagnetic resonance in the 3-cm band.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 32–37, January, 1978.The authors are grateful to E. P. Naiden for performing the x-ray measurements.     

Physicochemical modeling of precipitating and dissolving of gypsum in chloride solutions

Physicochemical modeling is used to study the isolation of sulfate ions as α (β)-CaSO₄ · 2H₂O from aqueous solutions. The equilibrium compositions of liquid, solid, and gas phases of the NA₂SO₄-CaCl₂-CO₂-H₂O system are calculated at 25°C, CO₂ partial pressures of 10^−1.53 kPa, CaCl₂/Na₂SO₄ molar ratios of 0.2–3.0, and CaCl₂ concentrations from 0.01 to 0.15 mol/kgH₂O. The Gibbs energies of formation for α(β)-gypsum were determined from experimental solubility data on the α(β)-gypsum-air-water system by solving the inverse problem of physicochemical modeling. The data obtained are ΔG° _f298 (α-CaSO₄ · 2H₂O) = −1796.446 kJ/mol and G° _f298 (β-CaSO₄ · 2H₂)) = −1797.317 kJ/mol. Published in Russian in Zhurnal Neorganicheskoi Khimii, 2006, Vol. 51, No. 5, pp. 889–894. This article was translated by the authors.     

1,3-Diacetylferrocene

A method is described for the preparation of 1,3-diacetylferrocene, in which ethylferrocene is first acetylated with acetyl chloride in the presence of AlCl₃ in methylene chloride to a mixture of isomeric acetylethylferrocenes. This mixture is then subjected to thin-layer chromatography, a mixture of the 1,1′- and 1,3-derivatives free from the 1,2-isomer being obtained. After oxidation of this mixture with MnO₂ to a mixture of 1,1′- and 1,3-diacetylferrocenes, the isomers are separated by preparative thin-layer chromatography.     

Extraction of transplutonium elements with diphenyl (alkyl)dialkyl-carbamoylmethyl phosphine oxides

Polydentate neutral organophosphorus compounds attract great interest as efficient extractants of transplutonium elements(TPE) from acid waste nuclear fuel element solution. With the view of a further search, reagents R′R″-PO-CH₂-CNO-R ₂ ^″' were synthetized and investigated. The solubility of R ₂ ^′ POCH₂CNOR ₂ ^″' vas investigated in organic solvents and in nitric acid solutions. This reagent was found to be the best one.