Analysis of a Hyperbolic System Modelling the Thermoelastic Impact of Two Rods

The problem on collinear collision of two thermoelastic rods possessing the same rheological parameters but of different length and temperature is considered, in so doing before the impact the rods move unidirectionally along a common longitudinal axis with distinct constant velocities. Lateral surfaces and free ends of both rods are heat insulated, and free heat exchange between the rods occurs within contacting ends. The rods' thermoelastic behavior is described by the Green–Naghdy theory. Two methods are used as the methods of solution, namely: D'Alembert's method and the ray method. D'Alembert's method is based on the analytical solution of equations of the hyperbolic type describing the dynamic behavior of the thermoelastic rods. This solution involves four arbitrary functions which are determined from the initial and boundary conditions and are piecewise constant functions. The ray method is based on the theory of discontinuities and also allows one to obtain the solution involving four arbitrary constants. Both solutions complement each other, since D'Alembert's solution enables one to analyze the influence of thermoelastic parameters on the values to be found, while the solution via the ray method is best suited for numerical investigation of the longitudinal coordinate dependence of the desired values at each fixed instant of the time beginning from the moment of rods' collision up to the moment of their rebound. To illustrate the both approaches, the problem of the rods' collision without account for the stress and temperature fields coupling is also considered.     

Implementation of Digital Unbiased FIR Filters with Polynomial Impulse Responses

This paper addresses the design and implementation of digital unbiased finite impulse response (FIR) filters with polynomial impulse response functions. The transfer function, its fundamental properties, and a general block-diagram are discussed for the impulse response represented with the l-degree Taylor series expansion. As a particular results, we show a fundamental identity uniquely featured to such filters in the transform domain. For low-degree impulse responses, the transfer functions are found in simple closed forms and represented in compact block-diagrams. The magnitude and phase responses are also analyzed along with the group delays. A comparison with predictive FIR filters is given. As examples of applications, filtering of time errors of local clocks is discussed along with the low-pass filter design employing a cascade of the unbiased FIR filters.     

Light‐Controlled Reversible Manipulation of Microgel Particle Size Using Azobenzene‐Containing Surfactant

The light‐induced reversible switching of the swelling of microgel particles triggered by photo‐isomerization and binding/unbinding of a photosensitive azobenzene‐containing surfactant is reported. The interactions between the microgel (N‐isopropylacrylamide, co‐monomer: allyl acetic acid, crosslinker: N,N′‐methylenebisacrylamide) and the surfactant are studied by UV‐Vis spectroscopy, dynamic and electrophoretic light scattering measurements. Addition of the surfactant above a critical concentration leads to contraction/collapse of the microgel. UV light irradiation results in trans‐cis isomerization of the azobenzene unit incorporated into the surfactant tail and causes an unbinding of the more hydrophilic cis isomer from the microgel and its reversible swelling. The reversible contraction can be realized by blue light irradiation that transfers the surfactant back to the more hydrophobic trans conformation, in which it binds to the microgel. The phase diagram of the surfactant‐microgel interaction and transitions (aggregation, contraction, and precipitation) is constructed and allows prediction of changes in the system when the concentration of one or both components is varied. Remote and reversible switching between different states can be realized by either UV or visible light irradiation.     

Pseudotransient Continuation-Based Steady State Solver: Extension to Zero Flow Rates

This paper presents and discusses an extension of the pseudotransient continuation-based steady state solver for hydraulic networks proposed previously to the case of zero flow rates. The original solver, which reduces the solution of the governing nonlinear algebraic equations to the numerical integration of an initial-value problem, has problems in situations in which the head derivative of the flow rate tends to infinity, as is the case with zero flow rates. The extension is on the basis of the use of a model headloss-flow relationship that coincides with the true one at zero and has a finite head derivative at that point. This modified steady state solver is free from some convergence problems that occur in Newton-Raphson method-based solvers when analyzing a pipe network with control devices. The paper includes the results of the numerical analysis of test networks, which demonstrate the convergence of the modified steady state solver for cases in which existing steady state solvers have troubles.     

Clever Nuclear Fuel Technology

The purpose of given article-consideration of the basic features of modern manufacturing of nuclear fuel which would confirm fact, that the manufacturer does everything that its production would respond not only to requirements of the consumer, but also to its expected inquiries, and would correspond to intended purposes of fuel. It was defined main tendencies and features of modern technology, especially in nuclear fuel production, on base of meeting discussions, themes of journal articles on nuclear subject. They are correspond with practice of JSC NCCP （Novosibirsk Chemical Concentrates Plant） and listed in the paper. In result of it number of base features of any advanced technology, not only nuclear, described here with examples from NCCP＇s practice. Of course, there is no certain list of all attributes of modern manufacturing as there is no limit to its perfection. These categories are forming by current needs of the market, but listed ones must be.     

Nanocomposite protective coatings based on Ti–N–Cr/Ni–Cr–B–Si–Fe,their structure and properties

The first results of manufacturing and investigations of a new type of nanocomposite protective coatings are presented. They were manufactured using a combination of two technologies: plasma-detonation coating deposition with the help of plasma jets and thin coating vacuum-arc deposition. We investigated structure, morphology, physical and mechanical properties of the coatings of 80–90 μm thickness, as well as defined the hardness, elastic Young modulus and their corrosion resistance in different media. Grain dimensions of the nanocomposite coatings on Ti–N–Cr base varied from 2.8 to 4 nm. The following phases and compounds formed as a result of plasma interaction with the thick coating surface were found in the coatings: Ti–N–Cr (200), (220), γ-Ni₃–Fe, a hexagonal Cr₂–Ti, Fe₃–Ni, (Fe, Ni)N and the following Ti–Ni compounds: Ti₂Ni, Ni₃Ti, Ni₄Ti, etc. We also found that the nanocomposite coating microhardness increased to H = 31.6 ± 1.1 GPa. The Young elastic modulus was determined to be E = 319 ± 27 GPa – it was derived from the loading–unloading curves. The protective coating demonstrated the increased corrosion resistance in acidic and alkaline media in comparison with that of the stainless steel substrate.     

N-Heterocyclic Carbenes and Their Metal Complexes Based on Histidine and Histamine Derivatives of Bacteriopurpurinimide for the Combined Chemo- and Photodynamic Therapy of Cancer

Photodynamic therapy (PDT) is currently regarded as a promising method for the treatment of oncological diseases. However, it involves a number of limitations related to the specific features of the method and the specific characteristics of photosensitizer molecules, including tumor hypoxia, small depth of light penetration into the tumor tissue, and low accumulation sensitivity. These drawbacks can be overcome by combining PDT with other treatment methods, for example, chemotherapy. In this work, we were the first to obtain agents that contain bacteriopurpurinimide as a photodynamic subunit and complexes of gold(I) that implement the chemotherapy effect. To bind the latter agents, N-heterocyclic carbenes (NHC) based on histidine and histamine were obtained. We considered alternative techniques for synthesizing the target conjugates and selected an optimal one that enabled the production of preparative amounts for biological assays. In vitro studies showed that all the compounds obtained exhibited high photoinduced activity. The C-donor Au(I) complexes exhibited the maximum specific activity at longer incubation times compared to the other derivatives, both under exposure to light and without irradiation. In in vivo studies, the presence of histamine in the NHC-derivative of dipropoxy-BPI (7b) had no significant effect on its antitumor action, whereas the Au(I) metal complex of histamine NHC-derivative with BPI (8b) resulted in enhanced antitumor activity and in an increased number of remissions after photodynamic treatment.     

First-principles modeling for optimal design,operation, and integration of energy conversion and storage systems

Energy and electricity consumption is expected to increase in the foreseeable future. Concurrently, sustainability concerns of fossil-based energy resources have motivated the use of renewable and reusable energy resources, and the use of more efficient energy-converting and energy-consuming systems. Consequently, for the past decade, there have been major theoretical and experimental advances in (1) energy generation from renewable and reusable resources and (2) energy-consuming and energy-converting devices. This review article focuses on the recent theoretical advances in renewable energy conversion devices such as photovoltaic and fuel cells, and in energy storage devices such as rechargeable batteries, flow batteries, and supercapacitors. Due to similar chemistry, electrochemistry, and physics of these systems, modeling similarities between different energy systems are highlighted. This review puts into perspective how first-principles mathematical modeling has contributed to systematic advances in the optimal design, operation, and integration of these systems. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16482 2019     

Characterization of free carbon forms in β-SiC nanopowders by temperature-programmed oxidation and Raman spectroscopy

Free carbon appears in β-SiC nanopowders as two-dimensional and ultrathin structures exposed predominantly on particle surfaces. These structures range from graphitic to lamella and amorphous, with more than one type being present at once. Their relative proportions and total percentage are quantified based on CO₂ evolution traces resulting from temperature-programmed oxidation (TPO). The TPO peak parameters are representative of the carbon nanostructure. The temperature of the peak maximum relates to the degree of graphitic order, whereas an apparent activation energy to structure homogeneity. Among the Raman parameters (for a 514-nm excitation wavelength), the area ratio of the D and G + D′ lines closely correlates with the relative proportion and structural perfection of the graphitic form. Furthermore, the area ratio of the β-SiC and carbon Raman lines is a strong function of the free carbon content in the range 0.1 to 5 wt%. The established correlations provide a guide to the consistent implementation of both techniques to characterize mixed carbon forms in β-SiC nanopowders.