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The influence of stainless steels microstructure evolution on the mechanical properties of pressure installation elements
PublicationIn this paper results of FEM analysis performed for pipe and 90o elbow, made of super duplex stainless steel, after precipitation of sigma phase (),were presented. Heat treatment conditions simulate accidental overheating that can occur in nuclear installations after cooling circulation fails. For initial and modified microstructure tensile test was performed and numerical description of work hardening curves was done. Verification...
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Determination of time delay between ventricles contraction using impedance measurements
PublicationThe paper presents a novel approach to assessment of ventricular dyssynchrony basing on multichannel electrical impedance measurements. Using a proper placement of electrodes, the sensitivity approach allows estimating time difference between chambers contraction from over determined nonlinear system of equations. The theoretical considerations which include Finite Element Method simulations were verified using measurements on...
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The influence of stainless steels microstructure evolution on the mechanical properties of pressure installation elements
PublicationIn this paper results of FEM analysis performed for pipe and 90o elbow, made of super duplex stainless steel, after precipitation of sigma phase (s), were presented. Heat treatment conditions simulate accidental overheating that can occur in nuclear installations after cooling circulation fails. For initial and modified microstructure tensile test was performed and numerical description of work hardening curves was done. Verification...
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Modelling of heat and mass transfer through wooden buildings
PublicationThe aim of this review paper is to examine the most recent available studies dealing with theoretical, numerical and experimental aspects related to modelling of heat and mass transfer through wooden buildings. The main thermophysical, mechanical and hygrometric properties of wood are firstly discussed. Then, the basic governing equations of heat and mass transfer phenomena are presented. A detailed description of the physical...
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Mechatronic Design Towards Investigation of the Temporo-Mandibular Joint Behaviour
PublicationA significant problem of the temporo-mandibular joint (TMJ) research is lack of data concerning geometry and position of TMJ discs. It leads to necessity of developing a driving method of the process optimization, which is based on chosen techniques of mechatronic design. In particular, the latter concerns a technique of experimentally supported virtual prototyping. On this stage, the research is characterized by well-verified...
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Pantographic metamaterials: an example of mathematically driven design and of its technological challenges
PublicationIn this paper, we account for the research efforts that have been started, for some among us, already since 2003, and aimed to the design of a class of exotic architectured, optimized (meta) materials. At the first stage of these efforts, as it often happens, the research was based on the results of mathematical investigations. The problem to be solved was stated as follows: determine the material (micro)structure governed by those...
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A Compact Basis for Reliable Fast Frequency Sweep via the Reduced-Basis Method
PublicationA reliable reduced-order model (ROM) for fast frequency sweep in time-harmonic Maxwell’s equations by means of the reduced-basis method is detailed. Taking frequency as a parameter, the electromagnetic field in microwave circuits does not arbitrarily vary as frequency changes, but evolves on a very low-dimensional manifold. Approximating this low-dimensional manifold by a low dimension subspace, namely, reduced-basis space, gives...
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Modeling of medium flow processes in transportation pipelines - the synthesis of their state-space models and the analysis of the mathematical properties of the models for leak detection purposes
PublicationThe dissertation concerns the issue of modeling the pipeline flow process under incompressible and isothermal conditions, with a target application to the leak detection and isolation systems. First, an introduction to the model-based process diagnostics is provided, where its basic terminology, tools, and methods are described. In the following chapter, a review of the state of the art in the field of leak detection and isolation...
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Computational analysis of power-law fluids for convective heat transfer in permeable enclosures using Darcy effects
PublicationNatural convection is a complex environmental phenomenon that typically occurs in engineering settings in porous structures. Shear thinning or shear thickening fuids are characteristics of power-law fuids, which are non-Newtonian in nature and fnd wide-ranging uses in various industrial processes. Non-Newtonian fuid fow in porous media is a difcult problem with important consequences for energy systems and heat transfer. In this...
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Buckling analysis of piezo-magnetoelectric nanoplates in hygrothermal environment based on a novel one variable plate theory combining with higher-order nonlocal strain gradient theory
PublicationIn the present investigation, a new first-order shear deformation theory (OVFSDT) on the basis of the in-plane stability of the piezo-magnetoelectric composite nanoplate (PMEN) has been developed, and its precision has been evaluated. The OVFSDT has many advantages compared to the conventional first-order shear deformation theory (FSDT) such as needless of shear correction factors, containing less number of unknowns than the existing...
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Modeling and simulation of blood flow under the influence of radioactive materials having slip with MHD and nonlinear mixed convection
PublicationRadioactive materials are widely in industry, nuclear plants and medical treatments. Scientists and workers in these fields are mostly exposed to such materials, and adverse effects on blood and temperature profiles are observed. In this regard, objective of the current study is to model and simulate blood based nanofluid with three very important radioactive materials, named as Uranium dioxide (UO2), Thorium dioxide (ThO2) and...
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Fluid structure interaction study of non-Newtonian Casson fluid in a bifurcated channel having stenosis with elastic walls
PublicationFluid–structure interaction (FSI) gained a huge attention of scientists and researchers due to its applications in biomedical and mechanical engineering. One of the most important applications of FSI is to study the elastic wall behavior of stenotic arteries. Blood is the suspension of various cells characterized by shear thinning, yield stress, and viscoelastic qualities that can be assessed by using non-Newtonian models. In this...
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Activation Energy and Inclination Magnetic Dipole Influences on Carreau Nanofluid Flowing via Cylindrical Channel with an Infinite Shearing Rate
PublicationThe infinite shear viscosity model of Carreau fluid characterizes the attitude of fluid flow at a very high/very low shear rate. This model has the capacity for interpretation of fluid at both extreme levels, and an inclined magnetic dipole in fluid mechanics has its valuable applications such as magnetic drug engineering, cold treatments to destroy tumors, drug targeting, bio preservation, cryosurgery, astrophysics, reaction kinetics,...
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Generalized temperature dependence model for anammox process kinetics
PublicationTemperature is a key operational factor influencing the anammox process kinetics. In particular, at temperatures below 15 °C, the specific anammox activity (SAA) considerably decreases. This study aimed to describe the temperature dependence of the anammox process kinetics in the temperature range from 10 to 55 °C, including the specific characteristics of“cold anammox”. The commonly used Arrhenius and extended and modifiedRatkowsky...
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INVESTIGATION OF THE CHARACTERISTICS OF A LOWEMISSION GAS TURBINE COMBUSTION CHAMBER OPERATING ON A MIXTURE OF NATURAL GAS AND HYDROGEN
PublicationT his article is devoted to the investigation of the characteristics of a low-emission gas turbine combustion chamber, which can be used in Floating Production, Storage and Offloading (FPSO) vessels and operates on a mixture of natural gas and hydrogen. A new approach is proposed for modelling the processes of burning out a mixture of natural gas with hydrogen under preliminary mixing conditions in gaseous fuel with an oxidizer...
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Molecular dynamics simulations reveal the balance of forces governing the formation of a guanine tetrad—a common structural unit of G-quadruplex DNA
PublicationG-quadruplexes (G4) are nucleic acid conformations of guanine-rich sequences, in which guanines are arranged in the square-planar G-tetrads, stacked on one another. G4 motifs form in vivo and are implicated in regulation of such processes as gene expression and chromosome maintenance. The structure and stability of various G4 topologies were determined experimentally; however, the driving forces for their formation are not fully...
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Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2
PublicationThe process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production plan-ning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage....
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A Quasi-2D MOSFET Model — 2D-to-Quasi-2D Transformation
PublicationA quasi-two-dimensional (quasi-2D) representation of the MOSFET channel is proposed in this work. The representation lays the foundations for a quasi 2D MOSFET model. The quasi 2D model is a result of a 2D into quasi 2D transformation. The basis for the transformation are an analysis of a current density vector field and such phenomena as Gradual Channel Detachment Effect (GCDE), Channel Thickness Modulation Effect (CTME), and...
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Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
PublicationTwo explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free...
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Approximate models and parameter analysis of the flow process in transmission pipelines
Publicationthe paper deals with the problem of early leak detection in transmission pipelines. First we present the derivation of state-space equations of the flow process in the pipelines. This description is then aggregated in order to obtain a principal model. Next, the problem of process model parameterization is addressed, taking into account the maximization of a model stability margin. The location of the maximum is determined using...
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Smooth Particle Hydrodynamics (SPH) approach in simulating large penetration into soil
PublicationA study of Smooth Particle Hydrodynamics (SPH) approach for predicting large soil deformation is presented. Theoretical basics of SPH method, including the equations governing, discussion of the importance of smoothing function length, contact formulation, boundary treatment and finally utilization in hydrocodes simulations are presented. An application of SPH to a real case of large penetrations (crater creating) into soil caused...
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Predicting the viscosity and electrical conductivity of ionic liquids on the basis of theoretically calculated ionic volumes
PublicationSelected physical properties of the ionic liquids might be quantitatively predicted based on the volumes of the ions these systems are composed of. It is demonstrated that the ionic volumes calculated using relatively simple theoretical quantum chemistry methods can be utilised to estimate the viscosities and electrical conductivities of various commonly used ionic liquids. The fitting formulas of the exponential form are offered...
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Discussion of “Development of an Accurate Time integration Technique for the Assessment of Q-Based versus h-Based Formulations of the Diffusion Wave Equation for Flow Routing” by K. Hasanvand, M.R. Hashemi and M.J. Abedini
PublicationThe discusser read the original with great interest. It seems, however, that some aspects of the original paper need additional comments. The authors of the original paper discuss the accuracy of a numerical solution of the diffusion wave equation formulated with respect to different state variables. The analysis focuses on nonlinear equations in the form of a single transport equation with the discharge Q (volumetric flow rate)...
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Asynchronous Method of Simultaneous Object Position and Orientation Estimation with Two Transmitters
PublicationThis paper proposes an object location method for all types of applications, including the Internet of Things. The proposed method enables estimations of the position and orientation of an object on a plane or in space, especially during motion, by means of location signals transmitted simultaneously from two transmitters placed on the object at a known distance from each other. A mathematical analysis of the proposed method and...
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Energy conversion in systems-contained laser irradiated metallic nanoparticles - comparison of results from analytical solutions and numerical methods
PublicationThis work introduces the theoretical method of metallic nanoparticles’ (NPs’) heat and mass transfer where the particles are coated on a surface (base), together with considering the case wherein nanoparticles move freely in a pipe. In order to simulate the heat transfer, energy and radiative transfer equations are adjusted to the considered issue. NPs’ properties are determined following the nanofluidic theories, whereas absorption...
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Non-linear circuit model of a single doubly-fed induction machine formulated in natural axes for drive systems simulation purposes
PublicationMathematical modelling and a circuit model formulated in natural axes of a single doubly-fed induction machine, with the account of magnetic circuit nonlinearity are presented in the paper. Derivation of the model differential equations was based on Lagrange's energy method. State functions of magnetic elements in the model are non-linear and depend on all currents flowing in the machine windings and on the angle of rotor position....
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Modelling of joining route segments of differential curvature
PublicationThe paper presents a new general method of modelling route segments curvature using differential equations. The method enables joining of route segments of different curvature. Transitional curves of linear and nonlinear curvatures have been identified in the case of joining two circular arcs by S-shaped and C-oval transitions. The obtained S-shaped curves have been compared to the cubic C-Bezier curves and to the Pythagorean hodograph...
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The behavioural model of graphene field-effect transistor
PublicationThe behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-states characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations...
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Extended micropolar approach within the framework of 3M theories and variations thereof
PublicationAs part of his groundbreaking work on generalized continuum mechanics, Eringen proposed what he called 3M theories, namely the concept of micromorphic, microstretch, and micropolar materials modeling. The micromorphic approach provides the most general framework for a continuum with translational and (internal) rotational degrees of freedom (DOF), whilst the rotational DOFs of micromorphic and micropolar continua are subjected...
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Key issues in modeling and optimization of lignocellulosic biomass fermentative conversion to gaseous biofuels
PublicationThe industrial-scale production of lignocellulosic-based biofuels from biomass is expected to benefit society and the environment. The main pathways of residues processing include advanced hydrolysis and fermentation, pyrolysis, gasification, chemical synthesis and biological processes. The products of such treatment are second generation biofuels. The degree of fermentation of organic substances depends primarily on their composition...
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Improved Performance of 1-Ethyl-3-Methylimidazolium Tetrafluoroborate at Steel/HCl Interface by Iodide Ions
PublicationThe corrosion and corrosion inhibition of St37 steel in 0.1 M HCl solution by 1-ethyl-3-methylimidazolium tetrafluoroborate (EMITFB) and the effect of addition of KI on the inhibitive performance of EMITFB have been examined by electrochemical [electrochemical impedance spectroscopy, potentiodynamic polarization, and dynamic electrochemical impedance spectroscopy (DEIS)] and surface examination [scanning electron microscope (SEM)...
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Homoisocitrate dehydrogenase from Candida albicans: properties, inhibition, and targeting by an antifungal pro-drug
PublicationThe LYS12 gene from Candida albicans, coding for homoisocitrate dehydrogenase was cloned and expressed as a His-tagged protein in Escherichia coli. The purified gene product catalyzes the Mg2+- and K+-dependent oxidative decarboxylation of homoisocitrate to alpha-ketoadipate. The recombinant enzyme demonstrates strict specificity for homoisocitrate. SDS-PAGE of CaHIcDH revealed its molecular mass of 42.6±1 kDa, while in size-exclusion...
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The comparison of antioxidant properties and nutrigenomic redox-related activities of vitamin C, C-vitamers, and other common ascorbic acid derivatives
PublicationThe term ‘vitamin C’ describes a group of compounds with antiscorbutic activity of L-ascorbic acid (AA). Despite AA’s omnipresence in plant-derived foods, its derivatives have also been successfully implemented in the food industry as antioxidants, including the D-isomers, which lack vitamin C activity. This study aimed to determine the relationship between redox-related activities for five derivatives of AA using electrochemical,...
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Ab initio chemical kinetics of Isopropyl acetate oxidation with OH radicals
PublicationGlobal reactivity descriptors of isopropyl acetate (IPA) and thermo-kinetic aspects of its oxidation via OH radicals have been studied. Transition state theory (TST) was utilized to estimate the bimolecular rate constants. Ten oxidation pathways have been investigated, and all of them are exothermic. The potential energy diagram has been sketched using different pre- and post-reactive complexes for all reaction pathways. Rate coefficient...
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COMPARISON OF HEAT TRANSFER CHARACTERISTICS IN SURFACE COOLING WITH BOILING MICROJETS OF WATER, ETHANOL AND HFE7100
PublicationThe basis of microjet technology is to produce laminar jets which when impinging the surface have a very high kinetic energy at the stagnation point. Boundary layer is not formed in those conditions, while the area of film cooling has a very high turbulence resulting from a very high heat transfer coefficient. Applied technology of jet production can result with the size of jets ranging from 20 to 500μm in breadth and 20 to 100μm...
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Chemical and biological evaluation of antioxidant activity of endogenous redox-active compounds compared to plant-derived exogenous antioxidants
PublicationThe research conducted so far has shown that endogenous antioxidants, despite being regarded as the first line of antioxidant defense, may not be sufficient to maintain redox homeostasis in cells exposed to oxidative stress. The results obtained in the doctoral dissertation show that endogenous redox-active compounds were moderate or weak scavengers of ABTS and DPPH radicals, while in cellular setting, their impact on the reducing...
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β-cyclodextrin-containing polymer based on renewable cellulose resources for effective removal of ionic and non-ionic toxic organic pollutants from water
PublicationA novel, bio-derived cyclodextrin-based trifunctional adsorbent has been successfully synthesized for efficient, rapid and simultaneous removal of a broad-spectrum of toxic ionic (anionic and cationic dyes) and non-ionic organic pollutants from water. The composition, morphology and the presence of functional groups in the obtained sorption material were characterized by elemental analysis, XRD, SEM, and FTIR spectroscopy. The...
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Electrochemical synthesis of 2D copper coordination-polymers: Layer-stacking deviation induced by the solvent and its effect on the adsorptive properties
PublicationA 2D Cu-based Metal-Organic Framework (MOF), namely copper-terephthalate (Cu(1,4-BDC)), was successfully synthesized by electrochemical method for effective methylene blue (MB) sorption from aqueous solutions. The composition, morphology, and the presence of functional groups in the obtained material were verified by Fourier Transform Infrared spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD), Thermal (TGA), and Elemental (EA)...
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Numerical Test for Stability Evaluation of Discrete-Time Systems
PublicationIn this paper, a new numerical test for stability evaluation of discrete-time systems is presented. It is based on modern root-finding techniques at the complex plane employing the Delaunay triangulation and Cauchy's Argument Principle. The method evaluates if a system is stable and returns possible values and multiplicities of unstable zeros of the characteristic equation. For state-space discrete-time models, the developed test...
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Analog modelling in qualitative analysis of vibration propagation
PublicationThe theory of dynamic systems is usually used to model the real systems. The models are based on solving ordinary differential equations, partial or difference, which enable obtaining the relation between input signal and the system response (output signal). The analogy between those models and generalized dynamic systems or control systems can be practically used. Vibration propagation can be described in a similar way as the...
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GPU-Accelerated 3D Mesh Deformation for Optimization Based on the Finite Element Method
PublicationThis paper discusses a strategy for speeding up the mesh deformation process in the design-byoptimization of high-frequency components involving electromagnetic field simulations using the 3D finite element method (FEM). The mesh deformation is assumed to be described by a linear elasticity model of a rigid body; therefore, each time the shape of the device is changed, an auxiliary elasticity finite-element problem must be solved....
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The application of nonlinear curvature sections in the turnout diverging track
PublicationThe paper presents the analytical method of modelling the diverging track of railway turnout with nonlinear curvature sections. These sections were used for smoothing the graph of curvature in the extreme areas of turnout. The problem of the curvature distribution was identified with the use of differential equations. The resulting solutions are of universal nature for example the ability of assuming any values of curvature at...
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Biomass estimation using a length-weight relationship in beetle larvae (Coleoptera: Aphodiidae, Histeridae, Hydrophilidae, Staphylinidae) obtained from cow dung
PublicationThis research enabled the relationship between length and dry body mass to be determined for 158 beetle larvaetaken from cow dung in north-eastern Poland. The larvae were divided into three morphological types, for which the power and linear function of the body length-weight relationship were determined. The linear regression equation characterizes the relationship between body weight and...
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Modelling a 6-dof manipulator using Matlab software
PublicationThis paper presents an alternative approach to modelling a revolute robot. The manipulator in question is Kuka KR 16-2. The main problem in robot modelling is a kinematic analysis. The revolute robot consist of six rotary joints (6-DOF) with base, shoulder, elbow and wirst. The kinematics problem is defined as a transformation from the cartesian space to the joint space. The Denavit- Hartenberg (D-H) model of representation was...
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Local mesh morphing technique for parametrized macromodels in the finite element method
PublicationThis paper presents a novel approach for enhancing the efficiency of the design process of microwave devices by means of the finite element method. It combines mesh morphing with local model order reduction (MOR) and yields parametrized macromodels that can be used to significantly reduce the number of variables in the FEM system of equations and acceleration of computer simulation. A projection basis for local reduction is generated...
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Flexomagneticity in Functionally Graded Nanostructures
PublicationFunctionally graded structures have shown the perspective of materials in a higher efficient and consistent manner. This study reports a short investigation by concentrating on the flexomagnetic response of a functionally graded piezomagnetic nano-actuator, keeping in mind that the converse magnetic effect is only taken into evaluation. The rule of mixture assuming exponential composition of properties along with the thickness...
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An inclination in Thermal Energy Using Nanoparticles with Casson Liquid Past an Expanding Porous Surface
PublicationPhysical aspects of inclined MHD nanofluid towards a stretching sheet embedded in a porous medium are visualized. Two types of nanoparticles are used named as copper and alumna dioxide with water as base fluid. Similarity transformations are used to convert the partial differential equations into the set of ordinary differential equation. Closed solutions are found to examine the velocity and the temperature profiles. It is examined...
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Determination of the refractive index and wavelength‐dependent optical properties of few‐layer CrCl3 within the Fresnel formalism
PublicationBased on previous reports on the optical microscopy contrast of mechanically exfoliated few layer CrCl3 transferred on 285 nmand 270 nmSiO2 on Si(100), we focus on the experimental determination of an effective mean complex refractive index via a fitting analysis based on the Fresnel equations formalism. Accordingly, the layer and wavelength-dependent absorbance and reflectance are calculated. Layer and wavelength-dependent optical...
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Approximation of Fractional Order Dynamic Systems Using Elman, GRU and LSTM Neural Networks
PublicationIn the paper, authors explore the possibility of using the recurrent neural networks (RNN) - Elman, GRU and LSTM - for an approximation of the solution of the fractional-orders differential equations. The RNN network parameters are estimated via optimisation with the second order L-BFGS algorithm. It is done based on data from four systems: simple first and second fractional order LTI systems, a system of fractional-order point...
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THE COMPOSITION MODULATION EFFECT IN GaInPAs SOLID SOLUTIONS AS A MANIFESTATION OF ENERGY RESONANCE AFTER MATERIAL'S SPINODAL DECOMPOSITION
PublicationThe Cahn-Hilliard model concepts are extended to describe the spinodal decomposition of Ga$_x$In$_{1-x}$P$_y$As$_{1-y}$ solid solutions grown on the InP substrate. The energy of elastic deformation of the thin layer of a solid solution was calculated on the assumption of its coherent conjugation with the massive InP substrate. The excess energy of component mixing in the solid phase was modeled in accordance with the simple solution...