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Search results for: elastic electron scattering
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The point estimate method in a reticulated shell reliability analysis
PublicationThe objective of this paper is to present an application of the point estimate method (PEM) that can determine the probabilistic moments for engineering structures. The method is reasonably robust and adequately accurate for a wide range of practical problems. It is a special case of numerical quadrature based on orthogonal polynomials. The main advantage of this method is that, unlike FORM or SORM, it is not necessary to carry...
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Comparison of classical Winter's bracing requirements of compressedtruss chord with stability analysis of 3D truss-model
PublicationMost code requirements concerning bracing are based on principles developed by Winter. The present research is devoted tostudy a lateral buckling of truss with linear elastic side supports. The classical Winter's model of truss chord in the case ofout of the truss plane buckling is compared with nonlinear analysis of 3D truss model. Full bracing condition, that permitsthe truss chord to support load level corresponding to an unbraced...
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Composites in energy storing prosthetic feet
PublicationComposites reinforced with carbon and glass fibers have become the commonly used material in the production of energy storing prosthetic feet (ESPF/elastic feet prostheses). Their properties ensure a stable and light structure that allows for accumulation, storage and release of energy during walking, thus ensuring an increase in gait efficiency. Depending on the modification of the composite in terms of fiber selection, their...
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A hyperelastic model for soils with stress-induced and inherent anisotropy
PublicationIn this paper, modelling of the superposition of stress-induced and inherent anisotropy of soil small strain stiffness is8presented in the framework of hyperelasticity. A simple hyperelastic model, capable of reproducing variable stress-induced9anisotropy of stiffness, is extended by replacement of the stress invariant with mixed stress–microstructure invariant to10introduce constant inherent cross-anisotropic component. A convenient...
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Studies on formation and percolation in ionic liquids/TX-100/water microemulsions
PublicationTernary microemulsion systems of H2O/Triton X-100/[BMIM][Tf2N], and H2O/Triton X-100/[BMIM][PF6] were prepared, compared and characterized for phase behavior for different water/surfactant ratios, at 25 °C. It was found that a change of an anion structure in the ionic liquids determines the total monophasic area of the systems. A liquid crystalline mesophase was detected in H2O/Triton X-100/[BMIM][PF6]. The microemulsion domains...
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Simplified Approach for Broadband RF Testing of Low Loss Magneto-Dielectric Samples
PublicationIn this paper, an attractive measurement techniqueis proposed to retrieve the broadband permittivity and permeabil-ity of the magneto-dielectric materials. The proposed techniqueis quite novel which mitigates the major problems associatedwith the conventional broadband RF material characterizationtechniques such as numerical instability and phase uncertaintywhen the length of the sample exceeds...
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Comparison of simplified sum-over-state expressions to calculate resonance Raman intensities including Franck-Condon and Herzberg-Teller effects
PublicationSum-over-state (SOS) expressions to simulate absorption spectroscopy and resonance Raman (RR) scattering including Franck-Condon (FC) and Herzberg-Teller (HT) effects are described. Starting from the general SOS method, several simplified SOS formulae are derived. In particular, within the so-called independent mode displaced harmonic oscillator model, it is shown that including the vibronic structure in the absorption and RR spectra...
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Colored Tattoo Ink Screening Method with Optical Tissue Phantoms and Raman Spectroscopy
PublicationDue to the increasing popularity of tattoos among the general population, to ensure their safety and quality, there is a need to develop reliable and rapid methods for the analysis of the composition of tattoo inks, both in the ink itself and in already existing tattoos. This paper presents the possibility of using Raman spectroscopy to examine tattoo inks in biological materials. We have developed optical tissue phantoms mimicking...
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Nonreciprocal properties of elliptical ferrite coupled line junction
PublicationIn this paper the nonreciprocal properties of el-liptical ferrite coupled line (EFCL) junction are examined. In the analysis the technique combining spectral-domain approach (SDA) with coupled-mode method (CMM) is applied. The nu-merical results concerning gyromagnetic coupling coefficient of ferrite coupled lines and scattering matrix of EFCL junction are presented. The obtained results are validated with the use of commercial...
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Bending of a Three-Layered Plate with Surface Stresses
PublicationWe discuss here the bending deformations of a three-layered plate taking into account surface and interfacial stresses. The first-order shear deformation plate theory and the Gurtin-Murdoch model of surface stresses will be considered and the formulae for stiffness parameters of the plate are derived. Their dependence on surface elastic moduli will be analyzed.
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Two-photon double ionization of atoms in attosecond x-ray radiation fields
PublicationWe consider two-photon double ionization of helium with 100, 200, and 400 eV excess energy for the two ejected electrons, corresponding to photon energies of 89.5, 139.5, and 239.5 eV, respectively. We focus on the case of ultrashort pulses (two oscillations of the field) and develop an approach to calculate the two-photon transition matrix elements within the lowest order of the time-dependent perturbation theory. One of the...
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Endohedral gallide cluster superconductors and superconductivity in ReGa5
PublicationWe present transition metal-embedded (T@Gan) endohedral Ga clusters as a favorable structural motif for superconductivity and develop empirical, molecule-based, electron counting rules that govern the hierarchical architectures that the clusters assume in binary phases. Among the binary T@Gan endohedral cluster systems, Mo8Ga41, Mo6Ga31, Rh2Ga9, and Ir2 Ga9 are all previously known superconductors. The well-known exotic superconductor...
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Modal Adjustment of Rayleigh Based Structural Damping and Coordinate-Partitioning Algorithm Dedicated to Frictionless Contact Constraints between Multibody System and Structure Modelled with Finite Elements
PublicationThe paper presents a dedicated numerical algorithm. The algorithm is advantageous during investigations of the dynamics of a hybrid multibody / finite-elements system. We focus our attention on interactions resulting from mechanical contact. Pointwise contact connects a vertex of the multibody structure and a surface of the elastic reference body. Instead of a positive value of the relative penetration factor, constraint equations...
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Dissociation of furan-2-carboxylic acid by low energy electrons
PublicationElectron attachment to molecular target can lead to a variety of negative fragment ions. We experi- mentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C3H3O2 − COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup...
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Load introduction to composite columns revisited—Significance of force allocation and shear connection stiffness
PublicationThe AISC 360-16 Specification recommends that the design shear force between parts of a composite column in the load introduction area shall be calculated based on the force allocation at ultimate limit state. Applicability of this straightforward method to the load levels that usually arise in slender composite columns is questionable, as this capacity-based force allocation is only true when the axial force is equal to the plastic...
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Spectral Finite Element Method in Condition Monitoring and Damage Detection
PublicationIt is well known that the dynamic behaviour of engineering structures may carry very important and crucial information that can be further used for the assessment of their condition as well as detection of any damage induced. The current interest in monitoring techniques based on the propagation of guided elastic waves requires that numerical techniques used for modelling the phenomena associated must shift into the realm of high...
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Monte-Carlo Modeling of Optical Sensors for Postoperative Free Flap Monitoring
PublicationThis work aims to develop a numerical tissue model and implement software to simulate photon propagation using the Monte Carlo method to determine design guidelines for a physical measurement system. C++ was used for the simulation program, and Python as a programming environment to create an interface that allows the user to customize individual simulation elements, allowing for increased accuracy and flexibility when simulating...
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Monte-Carlo Modeling of Optical Sensors for Postoperative Free Flap Monitoring
PublicationThis work aims to develop a numerical tissue model and implement software to simulate photon propagation using the Monte Carlo method to determine design guidelines for a physical measurement system. C++ was used for the simulation program, and Python as a programming environment to create an interface that allows the user to customize individual simulation elements, allowing for increased accuracy and flexibility when simulating...
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Surface and interfacial anti-plane waves in micropolar solids with surface energy
PublicationIn this work, the propagation behaviour of a surface wave in a micropolar elastic half-space with surface strain and kinetic energies localized at the surface and the propagation behaviour of an interfacial anti-plane wave between two micropolar elastic half-spaces with interfacial strain and kinetic energies localized at the interface have been studied. The Gurtin–Murdoch model has been adopted for surface and interfacial elasticity....
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Enhanced cellulose extraction from agave plant (Agave americana Species) for synthesis of magnetic/cellulose nanocomposite for defluoridation of water
PublicationResearch on fluoride removal from water is currently focusing on the development of innovative materials for defluoridation water. The current study extracted and used enhanced cellulose from Agave americana species to synthesize a magnetic/cellulose nanocomposite for water defluoridation. Strong and light binary acids (H2SO4 and CH3COOH) were utilized to pretreat raw material to enhance cellulose extraction. Central composite...
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On Non-holonomic Boundary Conditions within the Nonlinear Cosserat Continuum
PublicationWithin the framework of the nonlinear micropolar elastic continuum we discuss non-holonomic kinematic boundary conditions. By non-holonomic boundary conditions we mean linear relations between virtual displacements and virtual rotations given on the boundary. Such boundary conditions can be used for modelling of complex material interactions in the vicinity of the boundaries and interfaces.
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Absence of superconductivity in fluorine-doped neptunium pnictide NpFeAsO
PublicationX-ray diffraction, specific heat, magnetic susceptibility and inelastic x-ray scattering measurements on the transurarium oxypnictides NpFeAsO and NpFeAsO0.85F0.15 are presented. No superconductivity down to 2 K was observed upon fluorine doping, contrary to the structurally analogous rare-earth pnictides. No modification of the phonon density of states was observed upon doping with fluorine. We discuss our results in light of...
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Zero-Pole Electromagnetic Optimization
PublicationA fast technique for the full-wave optimization of transmission or reflection properties of general linear timeinvariant high-frequency components is proposed. The method is based on the zeros and poles of the rational function representing the scattering parameters of the device being designed and it is the generalization of the technique developed for the design by optimization of microwave filters. The performance of the proposed...
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Analysis and characterization of coordination compounds by resonance Raman spectroscopy
PublicationResonance Raman spectroscopy has become a powerful tool to study excited-state geometries, excited-state charge distributions and photoinduced reaction dynamics in coordination compounds. Due to their rich photophysical properties coordination compounds are utilized for a variety of applications ranging from DNA sensing to photocatalysis. This review features recent applications of various resonance Raman scattering techniques...
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Strong ellipticity within the Toupin–Mindlin first strain gradient elasticity theory
PublicationWe discuss the strong ellipticity (SE) condition within the Toupin–Mindlin first strain gradient elasticity theory. SE condition is closely related to certain material instabilities and describes mathematical properties of corresponding boundary-value problems. For isotropic solids, SE condition transforms into two inequalities in terms of five gradient-elastic moduli.
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Coherent-wave Monte Carlo method for simulating light propagation in tissue
PublicationSimulating propagation and scattering of coherent light in turbid media, such as biological tissues, is a complex problem. Numerical methods for solving Helmholtz or wave equation (e.g. finite-difference or finite-element methods) require large amount of computer memory and long computation time. This makes them impractical for simulating laser beam propagation into deep layers of tissue. Other group of methods, based on radiative...
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Surface active fatty acid ILs: Influence of the hydrophobic tail and/or theimidazolium hydroxyl functionalization on aggregates formation
PublicationNine structurally-related fatty acid ionic liquids have been prepared and their thermal behavior as well as their ability to self-assemble in water has been investigated. The thermal properties were studied by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), while the aggregation behavior was analyzed by tensiometry, isothermal titration calorimetry (ITC), conductometry, dynamic light scattering (DLS),...
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Transiluminacyjne monitorowanie stanu przestrzeni podpajęczynówkowej
PublicationTransiluminacja tkanek ludzkiego ciała w celach diagnostycznych jest stosowana od ponad stu lat. Metoda transiluminacji w bliskiej podczerwieni z rozpraszaniem zwrotnym (NIRT-BSS) umożliwia ciągłe, bezinwazyjne monitorowanie zmian szerokości przestrzeni podpajęczynówkowej, które może być cennym narzędziem w ocenie zagrożenia obrzękiem mózgu. W rozprawie przedstawiono optyczny model rozchodzenia się promieniowania podczerwonego...
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An in situ technique for the assessment of adhesive properties of a joint under load
PublicationSlow crack propagation in adhesive bonded joints has been characterised using an asymmetric wedge test. Crack position was evaluated from strain gauge measurements, both in the debonded partof the joint and in the bonded zone. Test temperature was changed during loading, giving insight into bond evolution. The technique allows accurate, and virtually continuous, determination of crack position to be made, and therefore the evaluation...
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Identification of Optocoupler Devices with RTS Noise
PublicationThe results of noise measurements in low frequency range for CNY 17 type optocouplers are presented. The research were carried out on devices with different values of Current Transfer Ratio (CTR). The methods for identification of Random Telegraph Signal (RTS) in noise signal of optocouplers were proposed. It was found that the Noise Scattering Pattern method (NSP method) enables to identify RTS noise as non-Gaussian component...
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Zero-Pole Space Mapping for CAD of Filters
PublicationIn this paper, we propose a new space-mapping technique tailored to the CAD of microwave filters. The goal of space mapping is to achieve a satisfactory design with the minimal number of fine model evaluations. In our approach, the filter is represented by a rational function. To quickly align the coarse and fine models, and to speed up the direct optimization of the coarse model, we propose matching the zeros and poles of a rational...
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Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
PublicationA novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly...
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Comparison of non-linear statical analysis of truss with linear and rotational side supports and 3d roof model
PublicationIn the paper geometrically non-linear analysis of example truss with linear and rotational elastic side supports is compared with geometrically non-linear analysis of part of the roof construction with purlins and truss-bracing. For different stiffness of side-supports a non linear relation between normal force in compressed chord due to out of truss plane displacement has been calculated.
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Transverse surface waves on a cylindrical surface with coating
PublicationWe discuss the propagation of transverse surface waves that are so-called whispering-gallery waves along a surface of an elastic cylinder with coating. The coating is modelled in the framework of linearized Gurtin–Murdoch surface elasticity. Other interpretations of the surface shear modulus are given and relations to so-called stiff interface and stiff skin model are discussed. The dispersion relations are obtained and analyzed.
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Pressure effects on the electronic structure and superconductivity of (TaNb)0.67(HfZrTi)0.33 high entropy alloy
PublicationEffects of pressure on the electronic structure, electron-phonon interaction, and superconductivity of the high entropy alloy ( TaNb ) 0.67 ( HfZrTi ) 0.33 are studied in the pressure range 0–100 GPa. The electronic structure is calculated using the Korringa-Kohn-Rostoker method with the coherent potential approximation. Effects of pressure on the lattice dynamics are simulated using the Debye-Grüneisen model and the Grüneisen...
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Integrable zero-range potentials in a plane
PublicationWe examine general statements in the Wronskian representation of Darboux transformations for plane zero-range potentials. Such expressions naturally contain scattering problem solution. We also apply Abel theorem to Wronskians for differential equations and link it to chain equations for Darboux transforms to fix conditions for further development of the underlying distribution concept. Moutard transformations give a convenient...
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Generalized Taylor formula and shell structures for the analysis of the interaction between geosythetics and engineering structures of transportation lines
PublicationThe analysis of the interaction between geosynthetics and engineering structures (e.g. railroad bed, soil foundation, pipeline) assumes that the geosynthetic form elastic membranes or shell laid on different types of foundations. The mathematical description of that problems in continuous domain employs Laplace operator Δ or d’Alembert operator □. In this paper we demonstrate the analysis based on generalize Taylor formula, and...
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A Note on Reduced Strain Gradient Elasticity
PublicationWe discuss the particular class of strain-gradient elastic material models which we called the reduced or degenerated strain-gradient elasticity. For this class the strain energy density depends on functions which have different differential properties in different spatial directions. As an example of such media we consider the continual models of pantographic beam lattices and smectic and columnar liquid crystals.
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Superconductivity in LiGa2Ir Heusler type compound with VEC = 16
PublicationPolycrystalline LiGa2Ir has been prepared by a solid state reaction method. A Rietveld refnement of powder x-ray difraction data confrms a previously reported Heusler-type crystal structure (space group Fm-3m, No. 225) with lattice parameter a= 6.0322(1) Å. The normal and superconducting state properties were studied by magnetic susceptibility, heat capacity, and electrical resistivity techniques. A bulk superconductivity with...
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Interactions of positrons with atoms and molecules
PublicationThe positron is the antiparticle of the electron. It has the same mass as the electron, but opposite charge. The understanding of the interactions of positrons with normal matter, like atoms and molecules, is of interest in various scientific fields, like nuclear medicine, plasma physics and astronomy. In this talk we will give a short introduction to some theoretical methods to describe the interactions of positrons with atoms...
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Distortional buckling of thin-walled columns of closed quadratic cross-section
PublicationThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
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The Point Estimate Method in a Reticulated Shell Reliability Analysis
PublicationThe objective of this paper is to present an application of the point estimate method (PEM) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Modeling of Composite Shells in 6-Parameter Nonlinear Theory with Drilling Degree of Freedom
PublicationWithin the framework of a 6-parameter nonlinear shell theory, with strain measures of Cosserat type, constitutive relations are proposed for thin elastic composite shells. The material law is expressed in terms of five engineering constants of classical anisotropic continuum plus an additional parameter accounting for drilling stiffness. The theory allows for unlimited displacements and rotations. A number of examples are presented...
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Strong-coupling superconductivity of SrIr2 and SrRh2 : Phonon engineering of metallic Ir and Rh
PublicationExperimental and theoretical studies on superconductivity in SrIr2 and SrRh2 Laves phases are presented. The measured resistivity, heat capacity, and magnetic susceptibility confirm the superconductivity of these compounds with Tc = 6.07 and 5.41 K, respectively. Electronic structure calculations show that the Fermi surface is mostly contributed by 5d (4d) electrons of Ir (Rh), with Sr atoms playing the role of electron donors....
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5-Selenocyanato and 5-trifluoromethanesulfonyl derivatives of 2′-deoxyuridine: synthesis, radiation and computational chemistry as well as cytotoxicity
Publication5-Selenocyanato-2′-deoxyuridine (SeCNdU) and 5-trifluoromethanesulfonyl-2′-deoxyuridine (OTfdU) have been synthesized and their structures have been confirmed with NMR and MS methods. Both compounds undergo dissociative electron attachment (DEA) when irradiated with X-rays in an aqueous solution containing a hydroxyl radical scavenger. The DEA yield of SeCNdU significantly exceeds that of 5-bromo-2′-deoxyuridine (BrdU), remaining...
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Left-handed propagation characteristics of a dielectric and metal-loaded periodic circular waveguide
PublicationIn this paper, a periodic dielectric/metallic rod is located in a circular waveguide to obtain left-handed operation. Two geometries of the dielectric/metallic rod are proposed and examined. The dispersion characteristics of the investigated waveguides are obtained using a surface impedance model. Moreover, equivalent circuit models are proposed allowing for calculation of the dispersion characteristics and scattering parameters...
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Accuracy of the discrete Green's function computations
PublicationThis paper discusses the accuracy of the discrete Green's function (DGF) computations. Recently closed-form expression of the DGF and its efficient numerical implementation were presented which facilitate the DGF applications in FDTD simulations of radiation and scattering problems. By carefully comparing the DGF results to those of the FDTD simulation, one can make conclusions about the range of the applicability of the DGF for...
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A study on transverse shear correction for laminated sandwich panels
PublicationThe paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing...
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On the Bending of Multilayered Plates Considering Surface Viscoelasticity
PublicationWe discuss the bending resistance of multilayered plates taking into account surface/interfacial viscoelasticity. Within the linear surface viscoelasticity we introduce the surface/interfacial stresses linearly dependent on the history of surface strains. In order to underline the surface viscoelasticity contribution to the bending response we restrict ourselves to the elastic behaviour in the bulk. Using the correspondence principle...
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Use of optical skin phantoms for calibration of dermatological lasers
PublicationA wide range of dermatological diseases can be efficiently treated using laser heating. Nevertheless, before the new laser is introduced into clinical practice, its parameters and ability to interact with human skin have to be carefully examined. In order to do that optical skin phantoms can be used. Such phantoms closely imitate the scattering and absorption properties of real human skin tissue along with its thermal properties,...