Search results for "Low"
showing 10 items of 12024 documents
On the solution of a parabolic PDE involving a gas flow through a semi-infinite porous medium
2021
Abstract Taking as start point the parabolic partial differential equation with the respective initial and boundary conditions, the present research focuses onto the flow of a sample of waste-water derived from a standard/conventional dyeing process. In terms of a highly prioritized concern, meaning environment decontamination and protection, in order to remove the dyes from the waste waters, photocatalyses like ZnO or TiO2 nanoparticles were formulated, due to their high surface energy which makes them extremely reactive and attractive. According to the basics of ideal fluid, the key point is the gas flow through an ideal porous pipe consisting of nanoparticles bound one to each other, for…
On the mechanics of magnetic fluids with field-induced phase transition: application to Couette flow
2018
The influence of Brownian diffusion and magnetophoresis, which are followed by phase transition, on the characteristics of a stationary plane Couette flow of magnetic fluid in a non-uniform magnetic field is discussed. The phase transition conditions in magnetic fluids are assumed as a natural restriction to the particle concentration increase in a non-uniform magnetic field. Profiles of the particles' concentration are calculated, and dependences of the volume magnetic force and of the viscous force are established. © 2018 Institute of Physics, University of Latvia.
Interferences in Locally Resonant Sonic Metamaterials Formed from Helmholtz Resonators
2019
[EN] The emergence of materials artificially designed to control the transmission of waves, generally called metamaterials, has been a hot topic in the field of acoustics for several years. The design of these metamaterials is usually carried out by overlapping different wave control mechanisms. An example of this trend is the so-called Locally Resonant Sonic Materials, being one of them the Phononic Crystals with a local resonant structure. These metamaterials are formed by sets of isolated resonators in such a way that the control of the waves is carried out by resonances and by the existence of Bragg bandgaps, which appear due to the ordered distribution of the resonators. Their use is b…
Control flow strategy in a receiver coil for nuclear magnetic resonance for imaging
2020
A mathematical discussion is introduced to describe the receiver coil characterizing a nuclear magnetic resonance for imaging, starting from a general shape of the conductor. A set of different inductance calculations have been introduced, varying the shape of the conductor. The inductance calculation led to a general expression of the magnetic field of a single coil characterized by a rectangular shape. A dynamic model of the receiver coil has been developed to represent the natural frequencies that characterize the operational bandwidth. A nonstationary control strategy is implemented to make a real time changing of the operational bandwidth. The frequency response of the coil generates …
Controlled Cytotoxicity of Plasma Treated Water Formulated By Open-air Hybrid Mode Discharge
2017
Plasma‐activated liquids (PAL) attract increasing interest with demonstrated biological effects. Plasma exposure in air produces stable aqueous reactive species which can serve as chemical diagnostics of PAL systems. Here, we tailor aqueous reactive species inside plasma‐activated water (PAW) through treating water with AC air spark and glow discharges in contact with water. Chemical probing demonstrated species specificity between two types of PAW. Spark discharge PAW contains urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0006 and urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0007, while urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0008and urn:x-w…
Experimental comparison of two control algorithms for low-saliency ratio interior permanent magnet synchronous motors
2018
In this paper, an experimental investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs) is described, analyzed and discussed. This investigation was carried out on a small-power IPMSM with low saliency ratio. More in detail, after a previous simulation study, the control techniques have been experimentally implemented and validated through means of a dSPACE® rapid prototyping system. The performances of the two algorithms have been evaluated and compared, obtaining interesting results.
The impact of temperature on electrical properties of polymer-based nanocomposites
2020
This work was supported by National Research Foundation of Ukraine, project 2020.02/0217. IK would also like to thank VIAA, State Education Development Agency for Latvian state fellowship. HK would like to thank Ministry of Education and Science of Ukraine, project for young researchers No. 0119U100435. In addition, SP and AAP are thankful for financial support from Latvian Council of Science via grant lzp-2018/2-0083. HK and AAP are grateful for the support from the COST Action CA17126.
Influence of the MgO barrier thickness on the lifetime characteristics of magnetic tunnelling junctions for sensors
2016
Magnetic tunnelling junctions increasingly enter the market for magnetic sensor applications. Thus, technological parameters such as the lifetime characteristics become more and more important. Here, an analysis of the lifetime characteristics of magnetic tunnelling junctions using the Weibull statistical distribution for CoFeB/MgO/CoFeB junctions is presented. The Weibull distribution is governed by two parameters, the characteristic lifetime η of the population and the shape parameter β, which gives information about the presence of an infant mortality. The suitability of the Weibull distribution is demonstrated for the description of dielectric breakdown processes in MgO-based tunnelling…
Multiphysical Modeling of Transport Phenomena During Laser Welding of Dissimilar Steels
2016
Abstract The success of new high-strength steels allows attaining equivalent performances with lower thicknesses and significant weight reduction. The welding of new couples of steel grades requires development and control of joining processes. Thanks to high precision and good flexibility, laser welding became one of the most used processes for joining of dissimilar welded blanks. The prediction of the local chemical composition in the weld formed between dissimilar steels in function of the welding parameters is essential because the dilution rate and the distribution of alloying elements in the melted zone determines the final tensile strength of the weld. The goal of the present study i…
On the N1-H and N3-H Bond Dissociation in Uracil by Low Energy Electrons: A CASSCF/CASPT2 Study.
2015
The dissociative electron-attachment (DEA) phenomena at the N1-H and N3-H bonds observed experimentally at low energies (<3 eV) in uracil are studied with the CASSCF/CASPT2 methodology. Two valence-bound π(-) and two dissociative σ(-) states of the uracil anionic species, together with the ground state of the neutral molecule, are proven to contribute to the shapes appearing in the experimental DEA cross sections. Conical intersections (CI) between the π(-) and σ(-) are established as the structures which activate the DEA processes. The N1-H and N3-H DEA mechanisms in uracil are described, and experimental observations are interpreted on the basis of two factors: (1) the relative energy of …