An investigation of the strength of branch areas in the piping of nuclear power installations

A three-dimensional shell finite-element method and a computer code have been developed in RRC ‘Kurchatov Institute’ for the strength analysis of branch pipe (nozzle) areas, which are among the most critical as regards strength components of pipes in both reactors and other systems. According to the method, the structure under study is broken up into eight-node isoparametric shell-type finite elements, each with eight or 18 integration points. The program was tested with the help of experimental results. The strength analyses of equal and unequal T-pipes were performed. Consideration was given to the variants with loading by pressure and moments (symmetric and asymmetric cases). The effects of fillet wall thickness and radius on the stressed state of the T-pipes were investigated.     

Creating Reference Standards for the Implementation of the State Verification Scheme for Water Content Measurement

Measurement Techniques - The results of the development of methods for the transfer of units of water content in solid and liquid substances and materials are presented. Four types of comparison...     

Aryl[2.2]paracyclophane-Based Chiral Regioisomeric Analogs of Salicyl Aldehyde: Novel Sources for Construction of Phenoxy-Imine Ligands

The efficient, high-yield approaches to two novel regioisomeric salicyl aldehyde analogs, 4-formyl-13-(2-hydroxyphenyl)-[2.2]paracyclophane and 4-formyl-12-(2-hydroxyphenyl)-[2.2]paracyclophane ( iso -FHPhPC and pseudo -FHPhPC , respectively), constructed on the basis of an aryl[2.2]paracyclophane backbone are described. The key stage of the backbone formation is the Suzuki cross-coupling of paracyclophanyl halides with arylboronic acids. Efficient procedures for the resolution of the racemic hydroxy aldehydes into enantiomers via Schiff bases with enantiomers of α-phenylethyl amine were elaborated, and the absolute configurations of enantiomers were established on the basis of X-ray analysis of diastereomeric imines. Starting from these chiral hydroxy aldehydes the first representatives of bi-, tri-, and tetradentate phenoxy-imine ligands belonging to an aryl[2.2]paracyclophane family were obtained. The induction power of the ligands was tested in the Et₂Zn asymmetric addition to aldehydes.     

Laser Surface Alloying of Aluminum Alloys

Surface alloying of aluminum alloys by means of laser heating is considered. The surface hardness of aluminum increases to 5000–7000 MPa on alloying with pure metals and to 6500–8000 MPa on alloying with chemical compounds. The wear resistance of the surface layer is increased by a factor of 4–5 on alloying.     

Phase Transformation during Metallothermic Reduction of Tantalite

Metallurgist - In this study, phase transformations were examined during low temperature interactions of natural tantalite with powders of aluminum and Ca–Al addition alloy (69.4 wt% Ca)...     

Pseudogap State of Underdoped Cuprate Hts as a Display of The Jahn–Teller Pseudoeffect

For underdoped quasi-two dimensional cuprate antiferromagnets within the framework of the two-component model of charge carriers (holes and Zhang–Rice polarons) it is considered two near-degenerate states of hole molecular orbitals of one-site cluster Cu²⁺O₄ ²⁻ and two-site cluster Cu²⁺O₄ ²⁻+Cu²⁺O₄ ² in CuO₂ planes. It is shown that the vibronic mixing of these near-degenerate states with near energies separated by the energy barrier , leads to transition of the system to the pseudogap state with new quasilocal and local states of charge carriers. The supposition that the pseudogap state is a consequence of the Jahn–Teller pseudoeffect and that barrier is stipulated by magnetic interaction is discussed.     

Electrochemical properties of ceramic membranes based on SrTi0.5Fe0.5O3−δ in reduced atmosphere

The present work aims at the investigation of the electrochemical properties of SrTi_0.5Fe_0.5O_3−δ as a membrane material for hydrogen production via electrochemical reforming. The dependence of the electrical conductivity on the oxygen partial pressure, as well as the oxygen permeability in the range of 10⁻²⁰ atm ≤ pO₂$p_{{\text{O}}_2}$ ≤ 10⁻¹⁴ atm is examined. The oxygen permeability is measured by an electrochemical method. The dependences of ion current as a function of the electromotive force (EMF) at various temperatures, oxygen partial pressures and the membrane surface conditions (rough and activated by PrO_x) are studied. Finally, the values of hydrogen flux at different temperatures are calculated and a long term investigation during 600 h at pO₂$p_{{\text{O}}_2}$ = 10⁻¹⁹ atm, T = 1173 K is carried out. According to the present results, the permeation current increases with the increase of temperature, oxygen partial pressure gradient and activation by PrO_x. The long term investigation shows that the electrical resistance of the SrTi_0.5Fe_0.5O_3−δ ceramic membrane increases by 10%, possibly due to the formation of micro-domains into the material's volume and the decrease in the grain boundary conductivity, because of the segregation of dopant-rich layers near the grain boundaries.     

Synthesis and sensor propeties of crown-containing derivatives of 4-(1,5-diphenyl-Δ<Superscript>2</Superscript>-pyrazolin-3-yl)-1,8-naphthalimide

Previously undescribed derivatives of 4-(1,5-diphenyl-Δ²-pyrazoline-3-yl)-1.8-naphthalimide that contain a moiety of benzo-15-crown-5- and N-phenylaza-15-crown-5-ether in the composition of the N-aryl substituent at the imide nitrogen atom of the naphthalimide nucleus have been synthesized. The derived compounds have a long-wavelength band in the absorption spectra in the region of 480 nm owing to charge transfer from the electron-donor pyrazoline moiety onto the carbonyl groups of the carboxyimide group. The fluorescence peaks are located in the region of 670 nm. In the series of the synthesized pyrazolinylnaphthalimides, the effect of the nature of the N-aryl moiety on the spectral-luminescent properties has been analyzed. It has been shown that the annelation of the 15-crown-5-ether moiety with the benzene ring of the N-phenyl substituent of 4-pyrazolinyl-N-phenyl naphthalimide does not change the position of bands in the absorption and fluorescence spectra and has little effect on the fluorescence quantum yield. At the same time, the presence of the N-phenylaza-15-crown-5-ether group in the composition of the N-aryl moiety leads to a small hypsochromic shift of the peaks in the absorption and emission spectra and to a decrease in fluorescence intensity attributed to the occurrence of a nonradiative process of electron transfer from the N-aryl substituent onto the photoexcited naphthalimide chromophore. The proposed explanation for the observed spectral effects has been confirmed by the data of semi-empirical quantum-chemical calculations using the PM6 method. The complexation of crown-containing 4-pyrazolinylnaphthalimides was studied employing alkaline earth metal cations (Mg²⁺ and Ca²⁺) in acetonitrile solutions. ¹H NMR spectroscopy has revealed that the coordination of the cation occurs through the crown-ether receptor. Upon complexation, in the absorption and fluorescence spectra, a bathochromic shift of the peaks of the long-wavelength bands by 6–15 nm was observed. The binding of the Mg²⁺ cations by the benzo-15-crown-5-ether derivative of naphthalimide was accompanied by fluorescence quenching, while in the case of 4-pyrazolinylnaphthalimide containing an N-phenylaza-crown-ether moiety in the N-aryl substituent, during the complexation with the Ca²⁺ cations, fluorescence buildup was observed. The spectrofluorometric titration data were used to determine the stability constants of complexes of crown-containing naphthalimides with alkaline earth metal cations with a composition of 1: 1 in acetonitrile. These studies have shown that the synthesized compounds are promising from the standpoint of developing fluorescent sensors for cation analysis.     

Production of Tool Coatings by Chemicothermal Plasma Methods

Russian Engineering Research - Abstract—Two methods are considered for the production of wear-resistant coatings for cutting and stamping tools: plasma nitriding with subsequent oxidation;...     

Value creation in projects: Towards a narrative perspective

It is contended that value is a social construct, and that the processes of social construction are rooted in language. On this basis we argue that value creation is a process which lends itself to interpretation from a narrative perspective. Previous attempts at value creation have been promoted under the label of ‘value management’. There are two approaches which are identifiable in the literature. The first is based on the traditional narrative of value engineering (aka Hard VM) and is primarily directed towards cost reduction. The second more recent variant is labelled ‘soft’ value management (Soft VM) and is primarily directed towards the achievement of a shared understanding of the value criteria relating to an individual project. The two approaches are critiqued in terms of their underlying assumptions and it is suggested that they are best understood as different forms of narrative. The emerging literature on value creation is similarly critiqued in accordance with the adopted narrative perspective. The distinction is made between formalised narratives of value on the level of the organisations involved in the project coalition and the anecdotal stories which individuals use to make sense of their own lived experiences. Emphasis is given to the ways in which different narratives interact, and to the way in which they remain contestable over time. Particular attention is given to the confluence between storytelling and identity work.