Help Of Experimental Measurements Research Articles

БИОЛОГИЯЛЫҚ СҮТ ӨНІМДЕРІН СЕРПІМДІ ТОЛҚЫНДАРМЕН ЗЕРТТЕУ

The scientific article contains a pulsed ultrasonic installation in order to determine the temperature dependence of the density of biological fluids and the velocity of their elastic linear wave and the coefficient of adiabatic compressibility. With the help of experimental measurements and theoretical calculations, the temperature dependences of the density of the sample under study, the velocity of the linear wave, the coefficient of adiabatic compressibility (25-125)0C were studied for the first time, graphs of the dependences p=p(t), u=u(t), α5= α5 (t) were constructed. In order to study biological fluids, we used a thermos for domestic use. The source and receiver of the ultrasonic wave, a mirror reflecting the wave, a heater, and injection molding machines are placed in the biological liquid under study. We have positioned the piezoelectric element and the mirror at a certain distance. The required temperature and velocity of the elastic wave in the studied samples were measured using special curves a and B. Correct measurements of the installation.

A miniaturized highly selective MTM‐inspired filter for lowpass and triple‐band bandpass performance with configurable transmission zeros and bandwidth

SummaryThis paper presents a novel, compact, and highly selective metamaterial inspired filter with low insertion loss, lowpass, and triple‐band bandpass characteristics. The presence of five transmission zeros and seven poles facilitates highly selective filtering performance. The improved impedance matching and transmission characteristics have been achieved by embedding complementary split ring resonator as defected ground structure. The filter circuit area excluding 50 Ω feed lines is merely 0.17λg × 0.05λg at 3‐dB cut‐off frequency of lowpass passband (1.11 GHz). The 3‐dB fractional bandwidths of the three bandpass regions are 39.50% (1.3–1.94 GHz), 21.20% (3.12–3.86 GHz), and 21.06% (4.04–4.99 GHz) at the center frequencies of 1.62, 3.49, and 4.51 GHz, respectively. Intended filter also offers a wide stopband extending from 2.15 to 2.96 GHz at close to 20 dB attenuation level. Further, position of transmission zeros and 3‐dB passband bandwidths can be adjusted by carefully choosing structural design parameters. The metamaterial effect of the proposed filter has been demonstrated by plotting refractive index followed by validating the performance with the help of experimental measurements. No filter shows lowpass characteristic along with three bandpass performances as found by the authors exploring literature, which presents the novelty of the proposed work.

Magnetic properties of Pr bulk and clusters determined using density functional theory calculations

Lanthanide-based nanostructures have the potential to meet the current miniaturization demands of advanced devices such as magnetic memories with ultrahigh-storage densities. However, many questions about their fundamental properties remain unaddressed even for bulk and small nanostructures. From the application and scientific point of view, it is crucial to determine their structural stability, magnetic coupling, and magnetic anisotropy, as well as to identify the best structure that can simultaneously consider these properties. With the help of experimental measurements on Pr bulk and clusters, we quantitatively calculated the spin and orbital magnetic moments by using the density functional theory (DFT) method, where spin-orbit coupling (SOC) and non-collinearity are included self-consistently. We found that Pr bulk is in a singlet state with the atomic magnetic moments anti-ferromagnetically coupled along the in-plane direction, and it shows strong in-plane magnetic anisotropy. Obeying Hunds rule of negative values, the orbital magnetic moment remarkably contributes to total moments in the bulk and cluster phases. However, they cannot determine the experimental oscillation of cluster magnetism. The oscillation behavior, as a function of cluster size, as well as the enhanced magnetic moment with increasing temperature, can be interpreted as the anti-ferromagnetic coupling between atomic magnetic moments. Giant magnetic anisotropy energy of several hundreds of meV has been derived in both Pr bulk and clusters, which is an order of magnitude larger than the transition metal counterparts.

The Use of Energy Storage Devices of Uncontrolled Type on the Moscow Metro (Theory and Practice)

The problem of increasing energy saving and energy efficiency in the system of traction power supply of the Moscow Metro is considered due to the use of energy storage devices of uncontrolled type. The results of simulation modeling of the operation of an energy storage device of uncontrolled type in the system of traction power supply of the subway are presented.A particular line of the Moscow Metro, Filevskaya, was studied, on which experiments on the introduction of energy storage devices based on electrochemical super capacitors were conducted.With the help of experimental measurements, the electric power indicators of the operation of a stationary energy storage device had been obtained at regular service on the traction substation of the Filevskaya line of the Moscow Metro for several months. The maximum levels of the converted energies, the cyclicity, the efficiency of the plant operation, and the amount of the energy economy are determined.By statistical processing of the instantaneous values of the performance of the traction substation with the accumulator and the analysis of the data of the energy monitoring of the Moscow metro, an important parameter of reducing the installed capacity was investigated. The similarity of the data of theoretical calculations and experimental measurements is shown.

Digital modelling: a tool for optimizing heat treatments

During the manufacture, complex or large-sized pressure devices, constructed in self-hardening steels such as those of the CrMo type, can be subjected to several intermediate heat treatments, designed to prevent cold cracking, post-heating and dehydrogenation heat treatment, and to soften hardened structures in the heat-affected zone and de-stress welds (intermediate stress relieving), before the execution of the final post-weld heat treatment. In the majority of construction codes, the conditions for executing the intermediate treatments are not defined or precise enough. The present study, carried out on CrMo and CrMoV steels, made it possible to determine the effects produced by these various heat treatments, in different conditions of heat and duration, on dehydrogenation and the relaxing of residual stresses, through digital modelling. The predictions were tested with the help of experimental measurements on representative scale models (butt and tap welding of 150 mm thick in 75 passes). Optimized treatment conditions are proposed.

Influence of the surface charge on the operation of ballistic T-branch junctions: a self-consistent model for Monte Carlo simulations

We analyse the influence of the surface charge on the operation of ballistic T-branch junctions by means of a semi-classical 2D Monte Carlo simulator. We propose a new self-consistent model in which the local value of the surface charge is dynamically adjusted depending on the surrounding carrier density. The well-known parabolic behaviour of the central branch potential VC when biasing right and left branches in a push–pull fashion is found to be much influenced by the value of the surface charge in both the horizontal and vertical branches. With the help of experimental measurements performed in real devices, the influence of the width of the central branch on the values of VC and its relation to surface charge effects are also studied.

Detrimental Effects of Capacitors in Distribution Networks in the Presence of Harmonic Pollution

The main goal of this paper is to analyze the behavior of an electric power network in the presence of harmonic distortion, when capacitors are installed. The work starts from a case study, where failure and malfunctioning of an industrial plant are described with the help of experimental measurements. The theoretical and mathematical details of the phenomena involved are analyzed by suitable computer simulations. The study is performed by considering some important electrical quantities, evaluated according to the definitions proposed by the standard IEEE 1459. The results put in evidence that using some typical quantities, such as the power factor, could lead to ambiguous conclusions in evaluating the actual "quality" of the loads, and this can assume special importance in virtue of the economic relevance of such quantities