Search

The effect of pulsed electrolysis on the electrodeposition of Cu–Sn alloy from the sulfate–sulfuric acid electrolyte is studied. It is shown that the codeposition of copper and tin is observed only at the potentials, which provide the discharge of copper(II) ions under the diffusion control. The transient time of electroreduction of copper(II) ions and the concentrations of Cu2+ ions in the near-cathode region in the pause are calculated. It is shown that a decrease of the pause duration leads to the alloy deposition at lower current densities. It is found that the use of pulsed electrolysis enables one to raise significantly (by 3 times) the range of cathodic current densities for production of high-quality yellow-bronze coatings. The effect of pulse duration and amplitude on the qualitative and quantitative compositions of the alloy is determined. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article about synthesis of purin nucleosides containing glucose residues published in the February 9, 2005 issue.

The results of clinical and experimental morphological studies of regenerates forming after replacement of large defects of the abdominal wall and tibia with implants from different materials (polytetrafluoroethylene, reperene, prolene, titanium, and titanium nickelide) are analyzed. Study of the regenerate histology and fibroarchitectonics has shown good prospects of mesh constructions from titanium nickelide for effective surgical repair of these defects. The use of this implant seems to be theoretically well-based and promising, particularly under conditions of suppurative infection and low individual reparative regenerative potential. [ABSTRACT FROM AUTHOR]

The paper addresses forced vibrations in piping subsystems, which are induced due to the formation and separation of turbulent vortices in the flow of a fluid being transported. The excitation frequency is not a constant number but can take on values from a certain range, thus leading to difficulties and ambiguities in the vibration analysis of piping. To solve this problem, a so-called energy approach is put forward which enables one to determine the most physically governed frequencies of forced vibrations. The approach essentially consists in searching for the natural frequencies and modes of the fluid hydrodynamic vibrations whereby the minimum amount of energy leaves the piping subsystem, while the maximum one remains inside. The validity of the proposed approach is verified by test examples. The proposed methods have been used to analyze piping forced vibrations induced by turbulent vortices in the steam flow in the secondary coolant piping of nuclear power plants with WWER-1000 reactor. Natural frequencies and modes of mechanical, hydrodynamic, and coupled hydrodynamic vibrations have been determined; some recommendations of how to minimize the level of vibrations have been worked out. [ABSTRACT FROM AUTHOR]

The paper describes the method of initial parameters which is used for stress analysis of complex branched piping systems under static loading as well as under natural and forced harmonic vibrations, including the case of kinematic loading by displacement amplitudes. For the purpose of modeling arbitrary curved elements, in particular three-dimensional ones, the authors propose an inertialess rotary element of zero length, which turns coordinate axes of neighbor elements. The paper demonstrates the potentialities of the method for vibrodiagnostics of piping. [ABSTRACT FROM AUTHOR]

Methods of scanning electron microscopy, potentiodynamic polarization, and X-ray diffraction analysis were used to study the kinetic features of the electrodeposition process of the copper-tin alloy from an oxalic acid electrolyte and analyze the structure, composition, and luster of coatings formed under sonochemical treatment conditions at varied power of the ultrasonic field and current load. The ultrasonic treatment with power of 8-40 W dm-3 makes it possible to 2-8 times intensify the cathodic process and obtain coatings containing 10-15 wt % tin with luster of 20-40%. The specific content of tin in a coating being formed is nearly independent of the ultrasound power and grows with increasing the cathodic current density. [ABSTRACT FROM AUTHOR]

Potentiodynamic polarization method was used to study kinetic specific features of the electrodeposition of copper under a sonochemical treatment of a sulfuric acid electrolyte. The working current densities, scattering power of the electrolyte, the structure, microhardness, and luster of the formed coatings were determined depending ultrasonic field power and the presence of a thiourea additive in the electrolyte. It was found that it is advisable to perform the sonochemical electrodeposition of copper from a sulfuric acid electrolyte with addition of 0.003 g dm-3 of thiourea at a current density of 2 A dm-2 and ultrasonic vibration power of 8 W dm-3. [ABSTRACT FROM AUTHOR]

We have performed calculations of stress-strain state of cable-stayed aerial pipeline crossing in the operation state and of the additional effect of the inspection gauge application. In order to assess efforts in the pipe and cable stays of the aerial crossing, we apply analytical solutions combined with numerical simulations using the 3D PipeMaster software system. This comprehensive analysis allows one to assess stresses in the critical zones of the crossing, as well as to develop recommendations on strengthening the structure of the aerial crossing before its in-line inspection. [ABSTRACT FROM AUTHOR]

We propose a procedure for the numerical analysis of the stress-strain state and criteria of its admissible state in the course of repairs of the air crossings of gas mains with regard for possible defects of the pipe metal. Using the “3D PipeMaster” software complex, we compute different versions and present recommendations concerning the optimal location of pipe-laying machines with an aim of realization of the possibility of lifting the pipe to a height required for repair works with guaranteed validity of the prescribed conditions of strength. The values of tractive forces in the pipe-laying machines are determined. The optimal sites of fixing the pipeline in the transverse direction are indicated and the corresponding forces acting in the cables used to prevent the transverse motions of the pipeline are calculated. [ABSTRACT FROM AUTHOR]

The paper describes a method and main results of a refined stress-strain state evaluation for a welded joint of the hot collector to steam generator nozzle of a nuclear power plant with a WWÉR-1000 reactor, which takes into account a fuller range of the actual loading conditions in operation. In calculations, we considered the stresses induced by uncompensated thermal expansion of the reactor elements. The results of 3D finite element calculations suggest that the level of local stresses in the area of the joint exceeds the metal yield stress. The calculated stresses for the outer nozzle surface agree satisfactorily with the in-situ strain measurement data. [ABSTRACT FROM AUTHOR]

The aim of this work were to choose a quantitative optimality criterion for estimating the quality of plant LED lighting regimes inside space greenhouses and to construct regression models of crop productivity and the optimality criterion depending on the level of photosynthetic photon flux density (PPFD), the proportion of the red component in the light spectrum and the duration of the duty cycle (Chinese cabbage Brassica сhinensis L. as an example). The properties of the obtained models were described in the context of predicting crop dry weight and the optimality criterion behavior when varying plant lighting parameters. Results of the fractional 3-factor experiment demonstrated the share of the PPFD level participation in the crop dry weight accumulation was 84.4% at almost any combination of other lighting parameters, but when PPFD value increased up to 500µmol m -2 s -1 the pulse light and supplemental light from red LEDs could additionally increase crop productivity. Analysis of the optimality criterion response to variation of lighting parameters showed that the maximum coordinates were the following: PPFD = 500µmol m -2 s -1 , about 70%-proportion of the red component of the light spectrum (PPFD LEDred /PPFD LEDwhite = 1.5) and the duty cycle with a period of 501µs. Thus, LED crop lighting with these parameters was optimal for achieving high crop productivity and for efficient use of energy in the given range of lighting parameter values., (Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.)

A 3-factor experiment with 24-d vegetation of Brassica chinensis L. crops demonstrated the dependence of dry mass yield on lighting regimes provided by a lamp composed of white (color temperature 4000 K) and red (660 nm) LEDs (light-emitting diodes). Experimental data were used to build regressive dependences of plant dry mass and optimal light criterion (product of dry mass and photosynthesis efficiency) on 3 LEDs lamp parameters: photosynthetic photon flux density (PPFD), red and white PPFD ratio, and pulse period. The following LEDs light parameters were found to be optimal for the Chinese cabbage: time-averaged PFD - 500.μmol/(m².s), red and white PPFD ratio - 1.5 and pulse period - 501 ps. Considering the wattage rating for projectible vitamin greenhouse Vitacycle-To, continuous light should have PPFD = 430 pmol/(m²-s), rPPFD/wPPFD ratio - 1.5 and continuous light.

Outcomes of 36 accidents with 37 aircrafts (one mid-air collision) in the period of 2003-2010 have been analyzed. Of 71 ejected crew members 14 pilots died (19.7%), 26 pilots (36.6%) suffered injuries of varying severity and 31 pilots (43.7%) escaped noticeable injuries. The major causes of the deaths were late emergency escape and failure of the eject mechanism (EM). The majority of harmed pilots (n = 18, 69.2%) had slight injuries; one crew member (3.9%) was injured moderately and 7 pilots (26.9%), substantively. Most of the injuries occurred on parachute landing (40.3%). The main reasons for severe injury were parachute landing impact (69.2%) and EM failure (23.1%). Commonly injuries were caused to the head and neck (30.7%) and a bit less often to the lower and upper extremities (22.6 and 19.4% respectively). 14.5% of the injuries were brought to the body and 11.3%--to the back. Severe injuries included fractures of the spine (42.9%) and lower and upper extremities (42.9 and 14.2% respectively).

According to results of performed examinations scoliotic spinal deformity in flight personnel has a low impact on professional health. This is proved by: oligosymptomatic course of disease - lack of complaints of pain, moderate pain, which is revealed only in case of loading tests and palpation; preservation of supporting and movement spinal function; lack of worsening of deformity during the flight service. At the same time in flight personnel suffering from scoliosis was registered a low tolerance to ergometri; robe, which point to insufficient muscle reserve of lower extremities, abdominals and dorsum. This insufficient may have an adverse effect on G-tolerance of pilots serving in maneuvering aviation. According to this fact authors came to conclusion that first-degree scoliotic deformity is of importance for expert examination of pilots of high-performance aircraft. Scoliotic deformity in pilots of other branches of aviation is of importance only in case of clinical implications (pain syndrome, restraint of movement). From there, it is not necessary to make a record in regulatory documents of flight medical board about functional-compensatory spinal deformity (first- and second degree scoliosis) in flight personnel, except flight personnel of high-performance aircraft.

The authors designed the integrated diagnostic test as a model for psychophysiological assessment and prediction of the effectiveness of cerebral hemodynamics in subjects. The test includes the recording of blood flow velocity in the CCA and the level of psychopathisation.

The authors prove the necessity of transformation of medical service of Air Force of all levels within the framework of the realization of program "Development of medical supply of Armed Forces of Russian Federation 2008-2012". Goals, functions of different elements of medical service, responsibilities of performers are developed. These goals have fundamental differences from previous one. New organizational structure of medical service of Air Forces and criteria of the estimation of its effectiveness are suggested. Offers of further optimization of organizational medical structure and improvement of medical supply of Air Forces are developed.

The experiment with essentially healthy male subjects no older than 50 involved functional load testing and irradiation by a low-energy helium-neon laser according to the standard therapeutic regimen (0.2 ml/V/ 30 min/10 sessions). Biomedical evaluation of hemoaggregation was made by 30 parameters of a multifunctional diagnostic system characterizing three blood aggregation levels: rheological (biophysical), coagulolytic (biochemical) and system (mathematical). The investigation resulted in delineation of a single-vector hypodynamic transformation of biophysical and biochemical modules, i.e. decrease in the rheological and coagulative potential mediated by a moderate platelets disaggregation (24.6%) and hyperactivation of plasmin proferments in euglobulin fraction (126.76 %). Added sessions of percutaneous laser irradiation of blood were shown to induce a medium imbalance of biophysical and biochemical hemoaggregation. At the same time, low-energy laser did not modulate significantly the general functional state of human operator as the rheological and coagulative protective potential of organism remained reasonably high (88.89 and 87.5 %, respectively).