Accurate extraction of maximum current densities from the layout

A module for efficient extraction of maximum current densities from the layout has been developed and implemented within the CAD package PARIS. The corner-rounding dependence on technology parameters, such as numerical aperture and acid/base diffusion length, was simulated. A combination of classical and meshless FEM was used to obtain accurate results taking the simulated realistic shapes of the corners into account.     

Retrofitting Steam Turbines with Expired Service Life

Many pieces of equipment installed at thermal power stations (TPS) have an expired service life or are close to expiry and are obsolete. In addition, the structure of heat consumption by end users has changed. Among the ways for solving the problem of aging equipment is the retrofitting of turbines that allows for service life recovery and improvement of their performance to the modern level. The service life is recovered through replacement of high-temperature assemblies and parts of a turbine, and the performance is improved by retrofitting and major overhaul of low-temperature assemblies. Implementation of modern engineering solutions and numerical methods in designing upgraded flow paths of steam turbines considerably improves the turbine effectiveness. New flow paths include sabre-like guide vanes, integrally-machined shrouds, and effective honeycomb or axial-radial seals. The flow paths are designed using optimization and hydraulic simulation methods as well as approaches for improving the performance on the turbine blading and internal steam flow paths. Retrofitting of turbines should be performed to meet the customers' needs. The feasibility of implementation of one or another alternative must be determined on a case-by-case basis depending on the turbine conditions, the availability of reserves for generating live steam and supplying circulation water, and the demands and capacities for generation and delivery of power and heat. The main principle of retrofitting is to retain the foundation and the auxiliary and heat-exchange equipment that is fit for further operation. With the example of PT-60-130 and T-100-130, the experience is presented of a comprehensive approach to retrofitting considering the customer’s current needs and the actual equipment conditions. Due to the use of modern engineering solutions and procedures, retrofitting yields updating and upgrading of the turbine at a relatively low cost.     

Retrofitting Cogeneration Power Stations under Conditions of Reduction or Abandonment of Steam Delivery for Process Needs

Presently, when the structure of energy consumption by industrial enterprises is being changed, many type PT turbine units operate with limitations imposed on their operating conditions, while type R backpressure turbines are often shut down for a long time or even removed from operation. Thus, the problem of using steam previously intended for process needs combined with the loading of the main equipment and additional generation of power and heat becomes urgent for many power stations. Three main ways for solving this problem are examined in this paper. Potential alternatives for retrofitting of cogeneration power stations (TETS) with types PT and R turbines are discussed. Each alternative solves a specific problem brought about by the actual operating conditions of a turbine at a specific TETs. The results of retrofitting of PT-80-130 turbines with an increase in the throughput capacity of the intermediate pressure cylinder (IPC) and R-50-130 turbines with installation of an additional low-pressure cylinder (LPC) are presented. The experience in operation of the retrofitted R-50-130 turbine with an unconventional arrangement where an additional LPC is installed upstream the high-pressure cylinder (HPC) rather than between the generator and HPC is also described. The experience in the upgrading of TETs with installation of bottom steam turbines driven by steam from a process steam extraction that is not demanded for is presented. Depending on the conditions at a specific TETs, a bottom steam turbine can be installed on a new foundation or in the compartment of a dismounted turbine with the use of serviceable auxiliary and heat-exchange equipment.     

Phase diagram of the Li2SO4–Na2SO4 system

The thermal analysis and X-ray powder diffraction studies of the Li₂SO₄–Na₂SO₄ system, including the high-temperature X-ray diffraction technique, have elucidated four phases of variable composition: three solid solutions based on the α-Li₂SO₄, α-Na₂SO₄, and α-LiNaSO₄ high-temperature polymorphs, and a low-temperature β-LiNaSO₄ phase. α-Na₂SO₄-Base solid solution disintegrates into two phases via a monotectoid phase transformation. It is quite probable that the monotectoid process is related to the conversion of the second-order phase transition to the first-order phase transition.     

Methods for correction of selectivity of N-(2-sulfoethyl)chitosan-based materials towards platinum(IV) and palladium(II) ions

In this paper, we report methods for correction of selectivity of sorbents based on N-(2-sulfoethyl)chitosan towards platinum(IV) and palladium(II) in HCl solutions. The common method for correction of selectivity of the sorbents is variation of their modification degree with complexing groups. An increase in the degree of sulfoethylation of the chitosan leads to the significant increase in selectivity of sorption of palladium(II) over platinum(IV). Application of the N-(2-sulfoethyl)chitosan with the highest degree of sulfoethylation allows for selective separation palladium(II) from platinum(IV) (рН = 5.0). Palladium is quantitatively desorbed from the surface of the N-(2-sulfoethyl)chitosans by 3.5 mol/dm³ solution of HCl.     

Studying the Sensitivity of Graphene for Biosensor Applications

Technical Physics Letters - We have studied the response of graphene-film-based chips on SiC substrates (the relative change in the chip resistance) to coming into contact with fluorescein...     

The electrophysiological characteristics of the plasma membrane of rat macrophages at rest and under exposure to ATP]

The application of ATP in micromolar concentrations to the macrophages results in a biphasic response in the form of the short-time depolarization followed by a rather long hyperpolarization, the corresponding inward and outward macroscopic currents being observed. The ATP-induced hyperpolarization is accompanied by changes in current kinetics, I/V-curves pattern and shifting in the reversal potential. Such changes may be explained by a supposition that ATP activates an additional fraction of potassium channels with characteristics other than those in cells with initially low value of membrane potential. The data available are suggestive that in resting cells the inward rectification potassium conductance may dominate, whereas during ATP-induced hyperpolarization a certain type of Ca(2+)-dependent potassium conductance prevails. A rather high membrane potential in some part of macrophages, not treated with ATP, may be attributed to the latter type of conductance.     

Mlig-SKP1 Gene Is Required for Spermatogenesis in the Flatworm Macrostomum lignano

In a free-living flatworm, Macrostomum lignano, an S-phase kinase-associated protein 1 (SKP1) homologous gene was identified as enriched in proliferating cells, suggesting that it can function in the regulation of stem cells or germline cells since these are the only two types of proliferating cells in flatworms. SKP1 is a conserved protein that plays a role in ubiquitination processes as a part of the Skp1-Cullin 1-F-box (SCF) ubiquitin ligase complex. However, the exact role of Mlig-SKP1 in M. lignano was not established. Here, we demonstrate that Mlig-SKP1 is neither involved in stem cell regulation during homeostasis, nor in regeneration, but is required for spermatogenesis. Mlig-SKP1(RNAi) animals have increased testes size and decreased fertility as a result of the aberrant maturation of sperm cells. Our findings reinforce the role of ubiquitination pathways in germ cell regulation and demonstrate the conserved role of SKP1 in spermatogenesis.