At present for processing of complex geometrical channels of workpieces electrochemical dimensional processing, vibro-impact machining and vibro-extruding are widely used. However combined ...electrochemical mechanical processing, that unites anodic dissolution and plastic flow of material in space and time, provides the required characteristics of surface layer. Local action anodic dissolution changes cold work amount and accelerates dissolution of micro- and macro-cusps, this causes annealing of physical and mechanical parameters in processed segments and accross the whole surface profile the required strengthening degree is attained.
The authors examine annealing model for microsurface by grain displacement in channel where extrusion forcing is dictated by grains size and profile of narrow blade channel and also by actual processing conditions. Operating conditions that are recommended for implementation of combined electrochemical mechanical processing of impeller and turbine type workpieces are found by experiments.
In consequence of field research they determined availability of standard microgeometry across the whole surface profile by combined processing with vibrations hashing with up to 2030 Hz frequency and low voltage current (in operation range from 1,2 till 1,8 V). Therein technological cycle decreases up to two fold, this reduces inadmissible jumping of blade edges and dimensional allowance.
The physical motivations, present status, main results in study of cosmic rays and in the field of gamma-ray astronomy as well future plans of the TAIGA-1 (Tunka Advanced Instrument for cosmic ray ...physics and Gamma Astronomy) project are presented. The TAIGA observatory addresses ground-based gamma-ray astronomy and astroparticle physics at energies from a few TeV to several PeV, as well as cosmic ray physics from 100 TeV to several EeV. The pilot TAIGA-1 complex is located in the Tunka valley, ~50 km west from the southern tip of the lake Baikal.
A common issue in studies on liquid-phase chemical processes is that the natural solid nanoimpurities present in reagent-grade chemicals are ignored. Little is known about these impurities’ nature, ...sizes, concentrations, and behavior, yet they significantly affect the efficiency of antiscalants in municipal and laboratory solutions. Recent research has focused on: (i) estimating nanoimpurity concentrations in in-house deionized water and semiconductor-grade isopropanol using “light sheet” optical ultramicroscopy, and (ii) visualizing antiscalant sorption on these impurities. Using a fluorescent-tagged antiscalant aminobis(methylenephosphonic acid) (ADMP-F), we tracked its affinity to particulate matter in deionized water and reagent-grade KCl solutions. Our study showed that the total concentration of nanoparticles with a size larger than 20 nm is about 106 units/mL in deionized water and 105 units/mL in isopropanol. Extrapolation of these values to a size ≥1 nm resulted in concentrations of 1011 and 108 units/mL. The addition of KCl or ADMP-F significantly increased foreign nanoparticle populations. ADMP-F is selectively adsorbed by only some impurities, while most antiscalant molecules remain as true solution. To our knowledge, this is the first instance of fluorescently labeled aminoalkylphosphonates being able to differentiate particulate matter traces in reagent-grade purity solutions. Therefore, the role of nanoparticles as crystallization centers should be seriously reconsidered, especially in their important application in scale inhibition.
We study the current of chiral charge density in a Dirac semimetal with two Dirac points in momentum space, subjected to an externally applied time dependent electric field and in the presence of a ...magnetic field. Based on the kinetic equation approach, we find contributions to the chiral charge current, that are proportional to the second power of the electric field and to the first and second powers of the magnetic field, describing the interplay of the chiral anomaly and the drift motion of electrons moving under the action of electric and magnetic fields.
In an Arbuzov-type reaction branched chain and cyclic perfluoroolefins react with trimethylsilyl diethyl phosphite to give new fluorinated alkenylphosphonates. Radical addition of dialkyl phosphites ...in two cases yields fluoroalkylphosphonates, which could be converted to give the respective fluoroalkenylphosphonates using BF
3·NEt
3.
In a Arbuzov-type reaction branched chain and cyclic perfluoroolefins react with trimethylsilyl diethyl phosphite to give new fluorinated alkenylphosphonates. Two internal olefins furnish by a radical addition of dialkyl phosphites fluoroalkylphosphonates, which could be converted using BF
3·NEt
3 to give the respective fluoroalkenylphosphonates.
Voltage unbalance in power systems feeding AC traction power systems is a worldwide known problem. One of the main aspects of this problem is the negative effect of voltage unbalance on motor loads ...causing operating problems and economic damage. It is necessary to perform unbalanced power flow studies and calculate voltage unbalance indexes to assess this negative effect of voltage unbalance and the develop of compensating measures during the design stage. Usually, calculations of the AC traction power supply system and the distribution network feeding it are carried out separately during the design of new lines of railways electrified by alternating current (AC) and reconstructing of existing ones. This approach is a source of deviations in the power flow studies because the lack of consideration of mutual influences between the traction power system and the distribution power system. In this paper, we compare a digital model in which the traction power supply system and the distribution network are modeled separately with a model that considers mutual influences between the traction and external power supply systems, including power flows through the traction network caused by the distribution network (transit currents). For digital modeling of these processes, authors used ETAPTM software with eTraXTM package. It allows to run unbalanced power flow studies when the generation and load are being changed over time, including train movement. During a separate simulation of the traction power system and distribution network, traction network was modelled using the equivalent sources connected to traction substation buses and the distribution network was modeled taking into account the fact that traction load was given from the simulation of the traction power system. The traction load was considered as lumped loads connected to the traction substation buses.At the same time, in both cases, the unbalanced power flow study was carried out by the phase domain method. Based on the results of two models comparison, it was concluded that the combined model containing a traction power supply system and distribution network, is more effective in terms of improving the accuracy of assessment voltage unbalance in accordance with current regulatory and technical documents on power quality.
1,1,3,3,3-Pentafluoro-2-pentafluorophenyl-1,2-epoxypropane 1 reacted with trimethylphosphite giving two diastereomers, (Z)- and ...(E)-3,6-bis(trifluoromethyl)-3,6-bis(pentafluorophenyl)-1,4-dioxan-2,5-dione 2a, b in a 1:1 ratio, cyclodimerisation product of the intermediately generated α-lactone 4. Compounds 2a, b were hydrolysed to furnish 3,3,3-trifluoro-2-hydroxy-2-(2,3,4,5,6-pentafluorophenyl)propionic acid 5.
Voltage unbalance in power systems feeding AC traction power systems is a worldwide known problem. One of the main aspects of this problem is the negative effect of voltage unbalance on motor loads ...causing operating problems and economic damage. It is necessary to perform unbalanced power flow studies and calculate voltage unbalance indexes to assess this negative effect of voltage unbalance and the develop of compensating measures during the design stage. Usually, calculations of the AC traction power supply system and the distribution network feeding it are carried out separately during the design of new lines of railways electrified by alternating current (AC) and reconstructing of existing ones. This approach is a source of deviations in the power flow studies because the lack of consideration of mutual influences between the traction power system and the distribution power system. In this paper, we compare a digital model in which the traction power supply system and the distribution network are modeled separately with a model that considers mutual influences between the traction and external power supply systems, including power flows through the traction network caused by the distribution network (transit currents). For digital modeling of these processes, authors used ETAPTM software with eTraXTM package. It allows to run unbalanced power flow studies when the generation and load are being changed over time, including train movement. During a separate simulation of the traction power system and distribution network, traction network was modelled using the equivalent sources connected to traction substation buses and the distribution network was modeled taking into account the fact that traction load was given from the simulation of the traction power system. The traction load was considered as lumped loads connected to the traction substation buses.At the same time, in both cases, the unbalanced power flow study was carried out by the phase domain method. Based on the results of two models comparison, it was concluded that the combined model containing a traction power supply system and distribution network, is more effective in terms of improving the accuracy of assessment voltage unbalance in accordance with current regulatory and technical documents on power quality.
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