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Search results for: anisotropy
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Optical absorption and anisotropy of phosphorene flakes
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Pure cross-anisotropy for geotechnical elastic potentials
PublicationThe pure cross-anisotropy is understood as a special scaling of strain (or stress). The scaled tensor is used as an argument in the elastic stiffness (or compliance). Such anisotropy can be overlaid on the top of any elastic stiffness, in particular on one obtained from an elastic potential with its own stress-induced anisotropy. This superposition does not violate the Second Law. The method can be also applied to other functions...
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Pure cross-anisotropy for geotechnical elastic potentials
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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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Micromechanical analysis of friction anisotropy in rough elastic contacts
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Stripe order and magnetic anisotropy in the S=1 antiferromagnet BaMoP2O8
PublicationMagnetic behavior of yavapaiite-type BaMoP2O8 with the spatially anisotropic triangular arrangement of the S=1Mo4+ ions is explored using thermodynamic measurements, neutron diffraction, and density-functional band-structure calculations. A broad maximum in the magnetic susceptibility around 46 K is followed by the stripe antiferromagnetic order with the propagation vector k=(12,12,12) formed below TN≃21 K. This stripe phase is...
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Revealing the anisotropy effects on the critical magnetic field in CaC6 superconductor
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Influence of Superparamagnetism on Exchange Anisotropy at CoO/[Co/Pd] Interfaces
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Modeling of textural anisotropy in granular materials with micro-polar hypoplasticity
PublicationW artykule przedstawiono wyniki numerycznej wpływu anizotropii strukturalnej w materiałach granulowanych na powstawanie lokalizacji odkształceń. Obliczenia wykonano dla ściskania w płaskim stanie odkształcenia stosując metodę elementów skończonych na bazie mikropolarnego prawa hipoplastycznego. Wpływ anizotropii modelowano stosując skorelowane pola początkowego wskaźnika porowatości.
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On the modelling of anisotropy and destructuration of soft clays within the multi-laminate framework.
PublicationZaproponowano nowy model konstytutywny dla słabonośnych gruntów drobnoziarnistych, w którym anizotropię cech wytrzymałościowych połączono ze zmianami struktury szkieletu gruntowego. Model ten został sformułowany w ramach tzw. modeli wielopłaszczyznowych (multi-laminate) bazujących na teorii sprężysto-plastyczności. Przedstawiono praktyczne zastosowanie modelu do obliczeń nasypu drogowego na podłożu słabonośnym metodą elementów...
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Modeling of textural anisotropy in granular materials with stochastic micro-polar hypoplasticity.
PublicationW artykule przedstawiono wyniki numerycznej wpływu anizotropii strukturalnej w materiałach granulowanych na powstawanie lokalizacji odkształceń. Obliczenia wykonano dla ściskania w płaskim stanie odkształcenia stosując metodę elementów skończonych na bazie mikropolarnego prawa hipoplastycznego. Wpływ anizotropii modelowano stosując skorelowane pola początkowego wskaźnika porowatości.
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Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands
PublicationCoordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work...
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Magnetic anisotropy in the exchange-biased laser-patterned thin Co/CoO films
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Simple multi-laminate model for soft soils incorporating structural anisotropy and destructuration
PublicationZaproponowano nowy model konstytutywny należący do rodziny tzw. modeli wielopłaszczyznowych (multi-laminate) dla gruntów słabonośnych. Oryginalnymi rozwiązaniami w modelu są: wprowadzenie kierunkowo zależnej prekonsolidacji oraz uwzględnienie zmian anizotropii wytrzymałości na ściskanie podczas destrukturyzacji naturalnych gruntów słabonośnych. Model zweryfikowano dla podstawowych badań elementowych.
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Effect of fabric anisotropy on shear localization in sand during plane strain compression
PublicationW artykule przedstawiono wyniki numerycznej wpływu anizotropii strukturalnej w materiałach granulowanych na powstawanie lokalizacji odkształceń. Obliczenia wykonano dla ściskania w płaskim stanie odkształcenia stosując metodę elementów skończonych na bazie mikropolarnego modelu hipoplastycznego.
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Stress anisotropy characterisation with the help of Barkhausen effect detector with adjustable magnetic field direction
PublicationIn the paper we describe a novel apparatus for the measurement of the Barkhausen noise (BN) angular dependence, which in turn may be indicative of the stress induced anisotropy of magnetic properties. Such dependence can be further used for the stress distribution evaluation. The change of magnetization direction in the material is obtained by varying the magnetic flux density in two perpendicular yokes of the apparatus. We present...
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Surface-Step-Induced Magnetic Anisotropy in Epitaxial LSMO Deposited on Engineered STO Surfaces
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The Material Anisotropy Influence on Modelling of Rutting Test with Application of Linear Viscoelasticity Constitutive Equations
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Atomic-Scale Finite-Element Modeling of Elastic Mechanical Anisotropy in Finite-Sized Strained Phosphorene Nanoribbons
PublicationNanoribbons are crucial nanostructures due to their superior mechanical and electrical properties. This paper is devoted to hybrid studies of the elastic mechanical anisotropy of phosphorene nanoribbons whose edges connect the terminals of devices such as bridges. Fundamental mechanical properties, including Young’s modulus, Poisson’s ratio, and density, were estimated from first-principles calculations for 1-layer, 3-layer, and...
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Fluorescence anisotropy decay in the presence of multistep energy migration and back transfer in disordered two-component systems
PublicationPrzeprowadzono analizę zaniku anizotropii fluorescencji w sztywnym (lepkim) układzie dwuskładnikowym donor (Rodamina 6G)- akceptor (Rodamina B) z uwzględnieniem prostego i powrotnego transferu energii. Stwierdzono bardzo dobrą zgodność danych doświadczalnych z wynikami symulacji Monte Carlo. W pracy zaprezentowano specjalnie opracowany hybrydowy algorytm symulacji Monte Carlo anizotropii emisji, który jest bardzo wydajny w porównaniu...
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Hybrid Monte-Carlo simulations of fluorescence anisotropy decay in disordered two-component systems in the presence of forward and back energy transfer
PublicationW pracy przedstawiono hybrydowy algorytm symulacji Monte Carlo zaniku anizotropii emisji fluorescencji w układach dwuskładnikowych z uwzględnieniem prostego i powrotnego transferu energii. Poprawność nowego algorytmu symulacji Monte Carlo zweryfikowano poprzez porównanie z wynikami obliczeń teoretycznych otrzymanymi w ramach modelu SCDM i z wynikami standardowej symulacji Monte Carlo (algorytm 'step by step').
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Hybrid Monte-Carlo simulations of fluorescence anisotropy decayin three-component donor-mediator-acceptor systems in the presenceof energy transfer
PublicationW pracy przedstawiono nowy hybrydowy algorytm symulacji Monte-Carlo układu trójskładnikowego donor-mediator-akceptor. Działanie algorytmu zilustrowano na przykładzie zaników anizotropii emisji fluorescencji powyższego układu. Porównano wyniki hybrydowej symulacji Monte-Carlo z wynikami klasycznej metody ''step by step''. Stwierdzono bardzo dobrą zgodność wyników obu symulacji, przy czym algorytm hybrydowy wymaga znacznie krótszego...
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Unusual fluorescence anisotropy spectra of three-component donor-mediator-acceptor systems in uniaxially stretched polymer films in the presence of energy transfer
PublicationW pracy analizowano transfer energii w układzie donor-mediator-akceptor w osiowo rozciąganych foliach polimerowych. Stwierdzono, że informacja zawarta w orientacji wektora pola elektrycznego wiązki światła wzbudzającego układ jest zachowana po zajściu procesu transferu energii pomiędzy molekułami w foliach rozciąganych. Natomiast w foliach nierozciąganych fluorescencja mediatora i akceptora jest bardzo silnie zdepolaryzowana.
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Anomalous anisotropy of deuterium-grown boron-doped diamond and the role of boron-tetramers in the Mott-Insulator transition
Open Research DataWe show anisotropy in the superconductivity for boron-doped diamond thin films prepared with Microwave Plasma Assisted Chemical Vapor Deposition using deuterium-rich plasma. This anomalous phase transition is linked with the emergence of boson quantum entanglement states behaving as a bosonic insulating state. Here, we show that the superconducting...
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Magnetic anisotropy and structural flexibility in the f ield-induced single ion magnets [Co{(OPPh2) (EPPh2)N}2], E = S, Se, explored by experimental and computational methods
PublicationDuring the last few years, a large number of mononuclear Co(II) complexes of various coordination geometries have been explored as potential single ion magnets (SIMs). In the work presented herein, the Co(II) S = 3/2 tetrahedral [Co{(OPPh2)(EPPh2)N}2], E = S, Se, complexes (abbreviated as CoO2E2), bearing chalcogenated mixed donor-atom imidodiphosphinato ligands, were studied by both experimental and computational techniques. Specifically,...
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Ln2(SeO3)2(SO4)(H2O)2 (Ln=Sm, Dy, Yb): A Mixed‐Ligand Pathway to New Lanthanide(III) Multifunctional Materials Featuring Nonlinear Optical and Magnetic Anisotropy Properties
PublicationBottom-up assembly of optically nonlinear and magnetically anisotropic lanthanide materials involving precisely placed spin carriers and optimized metal-ligand coordination offers a potential route to developing electronic architectures for coherent radiation generation and spin-based technologies, but the chemical design historically has been extremely hard to achieve. To address this, we developed a worthwhile avenue for creating...
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Marcin Perzanowski dr inż.
PeopleHello, I work in the Department of Magnatic Materials and Nanostructures in the Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland. My current research is focused on: (1) exchange bias in multilayers and nanostructures, (2) supermagnetic effects in low-dimensional materials, (3) perpendicular magnetic anisotropy in thin films and nanostructures. Collaborations, comments, and suggestions are welcomed! If...
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Influence of anisotropic stiffness in numerical analyses of tunneling and excavation problems in stiff soils
PublicationIn the stiff overconsolidated soil deposits anisotropy influences small and intermediate strain stiffness and hence it has important impact on the results of discplacement preditcions in soil-structure modelling. The authors developed a cross-anisotropic soil model which combines both stress dependent and micro-structural anisotropy. The model is based on the anisotropic hyperelastic kernel for small strain stiffness. Reference...
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Modelling tunnelling-induced deformation in stiff soils with a hyperelastic–plastic anisotropic model
PublicationIn this paper, the tunnelling-induced deformation in anisotropic stiff soils is analysed using FE modelling. The influence of material description is investigated rather than an advanced simulation of the tunnelling method. A new hyperelastic– plastic model is proposed to describe the anisotropic mechanical behaviour of stiff highly overconsolidated soil. This model can reproduce the superposition of variable stress-induced anisotropy...
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A BODIPY‐Based Molecular Rotor in Giant Unilamellar Vesicles: A Case Study by Polarization‐Resolved Time‐Resolved Emission and Transient Absorption Spectroscopy
PublicationBODIPY and BODIPY-derived systems are widely applied as fluorophores and as probes for viscosity detection in solvents and biological media. Their orientational and rotational dynamics in biological media are thus of vital mechanistic importance and extensively investigated. In this contribution, polarization-resolved confocal microscopy is used to determine the orientation of an amphiphilic BODIPY-cholesterol derivative in homogeneous...
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Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
PublicationIn this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable...
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Excitation energy transfer in partly ordered polymer films differing in donor and acceptor transition moments orientation
PublicationBased on spectroscopic measurements selected properties of nonradiative Förster energy transport are studied in uniaxially stretched polyvinyl alcohol thin films for three systems differing in donor and acceptor transition moments orientation relative to the axis of stretching. In particular, donor – acceptor emission anisotropy spectra yield completely different regularities for these systems in uniaxially stretched films, whereas...
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Experimental observations on the creep behaviour of frozen soil
PublicationConstitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side...
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Behaviour of orthotropic surgical implant in hernia repair due to the material orientation and abdomen surface deformation
Publicationrelation to the different range of typical deformations observed in different directions and zones of abdomen surface due to the patients’ life activities, has a significant influence on the extreme junction forces in the mesh–tissue connections and hence the repair persistence. The finite element model of the orthotropic implant was developed, and the junction forces in the connections of tissue and mesh were studied. The kinematical...
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Anisotropic mechanical behavior and auxeticity of penta-graphene: Molecular statics/molecular dynamics studies
PublicationWe investigate the mechanical properties of penta-graphene (PG), a recently proposed two-dimensional carbon allotrope using atomistic simulation techniques combined with the empirical description of interatomic interactions. We report on the dependence of its three in-plane mechanical moduli (i.e. Young's modulus, Poisson's ratio and shear modulus) on the deformation direction, strain and temperature. We show that PG displays a...
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Novel tetrahedral cobalt(II) silanethiolates: structures and magnetism
PublicationThree heteroleptic complexes of Co(II) tri-tert-butoxysilanethiolates have been synthesized with piperidine [Co{SSi(OtBu)3}2(ppd)2] 1, piperazine [Co{SSi(OtBu)3}2(NH3)]2(μ-ppz)·2CH3CN 2, and N-ethylimidazole [Co{SSi(OtBu)3}2(etim)2] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(II) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear,...
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Photoluminescence as a probe of phosphorene properties
PublicationHere, we provide a detailed evaluation of photoluminescence (PL) as a comprehensive tool for phosphorene characterization with the emphasis on a prominent quantitative role of PL in providing fingerprint-like features due to its extreme sensitivity to the band structure details, anisotropy, disorder, external fields, etc. Factors such as number of layers, dimensionality, structural and chemical disorder, and environmental factors...
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Dual-wavelength laser polarimeter and its performance capabilities
PublicationA dual-wavelength optical polarimetric approach has been proposed as a means of elimination of the systematic errors and estimation of the optical anisotropy parameters for a single DKDP crystal. Our HAUP-related polarimeter uses two semiconductor lasers with the neighbouring wavelengths of 635 nm and 650 nm. Based on the temperature dependence analysis of small characteristic azimuths of light polarization with respect to the...
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Assessment of Wooden Beams from Historical Buildings Using Ultrasonic Transmission Tomography
PublicationThe main goal of this study was non-destructive evaluation of wooden elements using ultrasonic waves. The inspection was carried out on wooden beams from a historical object. Elastic wave signals were processed by ultrasonic transmission tomography to obtain imaging of the internal structure of tested elements without disturbing their state and integrity. The focus was on the influence of wood anisotropy on the propagation of ultrasonic...
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Influence of sensor design and optical properties of tissue on the photoplethysmographic signal
PublicationPhotopletysmography and an associated technique called pulse oximetry are still explored due to the expectations that they give a lot of information about the state of the patient and, also, due to the fact that they are non invasive. Knowledge about the impact of various parameters on the measured signal leads to a faster and a more reliable way of analyzing measurement results and finding the dependencies between the involved...
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Nanoparticle-free tissue-mimicking phantoms with intrinsic scattering
PublicationWe present an alternative to the conventional approach, phantoms without scattering nanoparticles, where scattering is achieved by the material itself: spherical cavities trapped in a silicone matrix. We describe the properties and fabrication of novel optical phantoms based on a silicone elastomer polydimethylsiloxane (PDMS) and glycerol mixture. Optical properties (absorption coefficient µa, reduced scattering coefficient µs',...
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EVALUATION OF THE SEMIVARIOGRAM SELECTION ON THE KRIGING INTERPOLATION
PublicationThe aim of the paper is to present the possibilities of geostatistical interpolation kriging method using in the process of generating digital terrain models (DTM). The source of data is a direct measurements realized with a precision GNSS positioning kinematic measurement technique RTN. Kriging algorithm was analysed, especially in the meaning of a semivariogram every step. Theoretical semivariogram selection influence on the...
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Detailed investigation of the phase transition inKxP4W8O32and experimental arguments for a charge density wave due to hidden nesting
PublicationDetailed structural and magnetotransport properties of monophosphate tungsten bronze Kx(PO2)4(WO3)8 single crystals are reported. Both galvanomagnetic and thermal properties are shown to be consistent with a charge density wave electronic transition due to hidden nesting of the quasi-1D portion of the Fermi surface. We also observe the enhancement of electronic anisotropy due to reconstruction of the Fermi surface at the Peierls...
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Determination of magnetisation conditions in a Double-Core Barkhausen Noise measurement set-up
PublicationThe magnetic Barkhausen effect is useful forassessing 1D and 2D stress states of ferromagnetic steelobjects. However, its extension to technically importantmaterials, such as duplex anisotropic steels, remains challenging. The determination of magnetisation inside the studied object and the electromagnet for various geometries, materials and magnetisation angles is a key issue.Three-dimensional, dynamic finite element analysis...
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"Raport z wstępnych badań własności stali trudnościeralnej 460HB",. ang "Report on preliminary tests of the properties of wear-resistant steel 460HB"
PublicationMikrostrukturę badanej stali trudnościeralnej 460HB stanowi drobnoziarnisty martenzyt odpuszczony, który jest właściwy dla stali konstrukcyjnych niskowęglowych, niskostopowych ulepszonych cieplnie. W przypadku blach grubych, do których zalicza się badana stal, struktura może ulec zaburzeniu, jeżeli w hutniczym procesie wytwórczym wystąpiła niejednorodność odkształcenia plastycznego i w konsekwencji tworzenie się pasm segregacyjnych,...
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Progress in the post weld residual stress evaluation using Barkhausen effect meter with a novel rotating magnetic field probe
PublicationWe report the progress in post weld residual stress evaluation using Barkhausen effect (BE) meter with rotating magnetic field probe. The novel probe of the BE meter contains two C-core electromagnets and searching coil with ferrite antenna. This meter allows automatic measurements of BE intensity envelopes at different angles of magnetizing field. The full process of measurement at given position of the probe takes about only...
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A general theory for anisotropic Kirchhoff–Love shells with in-plane bending of embedded fibers
PublicationThis work presents a generalized Kirchhoff–Love shell theory that can explicitly capture fiber-induced anisotropy not only in stretching and out-of-plane bending, but also in in-plane bending. This setup is particularly suitable for heterogeneous and fibrous materials such as textiles, biomaterials, composites and pantographic structures. The presented theory is a direct extension of classical Kirchhoff–Love shell theory to incorporate...
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Density functional LCAO calculations of vibrational modes and phonon density of states in the strained single-layer phosphorene
PublicationThe paper presents an investigation of phosphorene under axial strain on the phonon density of states and vibrational modes. The studies were performed by means of density functional theory (DFT) within the linear combination of atomic orbitals (LCAO). The strained models were constructed using optimised supercell techniques. The vibrational mode spectra were estimated for strains applied for both the zigzag and armchair directions...
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A general isogeometric finite element formulation for rotation‐free shells with in‐plane bending of embedded fibers
PublicationThis article presents a general, nonlinear isogeometric finite element formulation for rotation-free shells with embedded fibers that captures anisotropy in stretching, shearing, twisting, and bending - both in-plane and out-of-plane. These capabilities allow for the simulation of large sheets of heterogeneous and fibrous materials either with or without matrix, such as textiles, composites, and pantographic structures. The work...
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Superconductivity in CaBi2
PublicationSuperconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is DC/gTc = 1.41, confirming bulk superconductivity;...