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Search results for: continuum orbitals
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Finding Valence Antibonding Levels while Avoiding Rydberg, Pseudo-continuum, and Dipole-Bound Orbitals
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Successive Orbital Ordering Transitions inNaVO2
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Successive orbital ordering transitions in NaVO2
PublicationPomiary właściwości fizycznych NaVO2, który charakteryzuje się trójkątną siecią krystalograficzną, pokazują dwa przejścia typu orbitalnego. W temperaturze 98 K w systemie wystepuje przejście drugiego rodzaju. Natomiast poniżej 93 K obserwowane jest przejście pierwszego rodzaju.
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Posttraumatic Orbital Emphysema: A Numerical Model
PublicationOrbital emphysema is a common symptom accompanying orbital fracture. The pathomechanism is still not recognized and the usually assumed cause, elevated pressure in the upper airways connected with sneezing or coughing, does not always contribute to the occurrence of this type of fracture. Observations based on the finite model (simulating blowout type fracture) of the deformations of the inferior orbital wall after a strike in...
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Theoretical calculation of pKas of phosphoric (V) acidin the polarisable continuum and cluster-continuum models
PublicationW pracy oceniono dokładność modelu polaryzowalnego kontinuum (PCM) i mieszanego modelu klaster-kontinuum do przewidywania wartości trzech kolejnych stałych dysocjacji kwasu fosforowego (V). Obliczenia PCM na poziomie MP2/6-31+G(d,p) odtwarzają wartość pierwszego pKa z rozsądną niepewnością, jednak wartości kolejnych pKa obarczone są bardzo dużym błędem, nawet po podniesieniu poziomu teorii do metody zespolonej G3B3. Dopiero obliczenia...
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The experience of movement in orbital space architecture: A narrative of weightlessness
PublicationBased upon a combination of architectural theories, the knowledge of space environment, and psychology of isolated and confined environments, this qualitative research aims to study orbital space settlement in a way to get the built space congenial to the human experience of movement. In this sense, sensors, self-propulsion or mechanical actuators, the inhabitant’s mental and visual capacity for movement, as well as the represented...
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The experience of movement in orbital space architecture: A narrative of weightlessness
PublicationBased upon a combination of architectural theories, the knowledge of space environment, and psychology of isolated and confined environments, this qualitative research aims to study orbital space settlement in a way to get the built space congenial to the human experience of movement. In this sense, sensors, self-propulsion or mechanical actuators, the inhabitant’s mental and visual capacity for movement, as well as the represented...
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Applications of Tensor Analysis in Continuum Mechanics
PublicationA tensor field is a tensor-valued function of position in space. The use of tensor fields allows us to present physical laws in a clear, compact form. A byproduct is a set of simple and clear rules for the representation of vector differential operators such as gradient, divergence, and Laplacian in curvilinear coordinate systems. The tensorial nature of a quantity permits us to formulate transformation rules for its components...
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Acceleration waves in the nonlinear micromorphic continuum
PublicationWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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Tensile and flexural moduli for human orbital wall bones – comparative study
PublicationThe main aims of the current research were: (1) to analyze in detail the tensile modulus and ultimate tensile strength (UTS) of orbital wall bones separately for the left and right orbit of the same cadaver and (2) to compare the obtained results with a flexural modulus of the left and right orbit reported earlier by A. C. van Leeuwen et al. [14]. A set of 54 specimens of orbital superior and/or medial walls harvested from 16 human...
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Static and dynamic modelling blow- out type trauma of orbital wall
PublicationAuthors of the paper present initial results of finite element analysis of a blow-out type trauma of orbital wall. The research is liked with laboratory tests for the Young’s modulus of bones evaluation. In the finite element analysis the neighbourhood of orbital wall is modelled by triangle thin shell finite elements. In the paper results of nonlinear static and transient dynamic analysis (including damping) are compared. The...
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Orbital blowout trauma occurring at the workplace – clinical, biomechanical and legal aspects
PublicationIntroduction and objective: Craniofacial injury at the workplace may lead to orbital blowout fractures. The aim of the study is the development of own numerical model of the eye orbit, assessment of the damage zones, and comparing them with clinical examinations. In addition, the current legal status of patients after injuries is presented Material and methods: In laboratory tests performed on bones collected from the upper and...
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TiCoCrFeMn (BCC + C14) High-Entropy Alloy Multiphase Structure Analysis Based on the Theory of Molecular Orbitals
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Tensile modulus of human orbital wall bones cut in sagittal and coronal planes
PublicationIn the current research, 68 specimens of orbital superior and/or medial walls taken from 33 human cadavers (12 females, 21 males) were subjected to uniaxial tension untill fracture. The samples were cut in the coronal (38 specimens) and sagittal (30 specimens) planes of the orbital wall. Apparent density (ρapp), tensile Young’s modulus (E-modulus) and ultimate tensile strength (UTS) were identified. Innovative test protocols were...
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Odontogenic orbital cellulitis in a young man with complete vision loss – a case report
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Electronic and dynamical properties of CeRh2As2 : Role of Rh2As2 layers and expected orbital order
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Implementation of continuum damage in elasto-viscoplastic constitutive equations
PublicationW pracy opisano podstawowy wariant modelu Chaboche, oraz założenia i implementacje kontynualnego modelu zniszczenia do komercyjnego programu MES. W pracy zaprazentowano dwa podejścia zobrazowane na przykładach obliczeń numerycznych.
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Survey of modern trends in analysis of continuum damage mechanics
PublicationW artykule dokonano szerokiego przegladu literatury z zakresu mechaniki zniszczenia izotropowego. Przedstawiono równania stosowane w opisie zniszczenia materiału.
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Practical Applications for Single Pill Combinations in the Cardiovascular Continuum
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Sophistication assessment of existing FEM models of orbital blowout trauma: Is models valuation justified?
PublicationAfter a thorough study of the work entitled “Development and validation of an optimized finite element model of the human orbit”, some doubts aroused concerning the sophistication assessment of the existing finite element method (FEM) models of orbital blow-out. Although the work was unquestionably innovative, and the results were not only fascinating but also invaluable, the authors stated that their model was the most sophisticated...
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Continuous Optimisation Algorithms
PublicationKsiążka poświęcona jest zagadnieniom optymalizacji ciągłej. Oprócz klasycznych algorytmów gradientowych omawiane są w współczesne algorytmy bezgradientowe, które stosowane są z powodzeniem w optymalizacji globalnej. Większość prezentowanych algorytmów określona może być mianem metaheurystycznych. Zaliczyć do nich można metody optymalizacji inspirowane procesami zachodzącymi w przyrodzie, które dalej można dzielić na inspirowane...
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Numerical simulation of asphalt mixtures fracture using continuum models
PublicationThe paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasicontinuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate...
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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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FE analysis of reinforced concrete corbels with enhanced continuum models
PublicationW artykule pokazano wyniki MES symulacji wsporników żelbetowych. Zachowanie wsporników modelowano przy zastosowaniu 3 różnych modeli betonu: sprężysto-plastycznego, degradacji sprężystej i rozmytych rys. Modele rozszerzono o długość mikrostruktury przy zastosowaniu teorii nielokalnej. Wyniki numeryczne porównano z doświadczeniami z literatury.
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Modelling of concrete behaviour with a non-local continuum damage approach
PublicationW artykule przedstawiono wyniki numerycznej dla różnych problemów brzegowych związanych z powstawaniem rys w betonie. Obliczenia wykonano przy zastosowaniu modelu zniszczeniowego (z uwzględnieniem degradacji sztywności). Do opisu rys, model rozszerzono o nielokalność.
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Existence of periodic orbits for a perturbed vector field
PublicationPrzy nałożeniu pewnego warunku na odwzorowanie Poincarego, wyrażonego w języku indeksów iteracji, dowodzi się istnienia orbit periodycznych dla zaburzonego pola wektorowego.
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Rigorous numerics for critical orbits in the quadratic family
PublicationWe develop algorithms and techniques to compute rigorous bounds for finite pieces of orbits of the critical points, for intervals of parameter values, in the quadratic family of one-dimensional maps fa(x)=a−x2. We illustrate the effectiveness of our approach by constructing a dynamically defined partition P of the parameter interval Ω=[1.4,2] into almost 4 million subintervals, for each of which we compute to high precision the...
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Acrodermatitis continua Hallopeau
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Continuum models for pantographic blocks with second gradient energies which are incomplete
PublicationWe postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy...
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Zero-range potentials for Direc particles: scattering and related continuum problems
PublicationW pracy przedstawiono rozszerzenie metody potencjałów zerowego promienia, szeroko wykorzystywanej w nierelatywistycznej mechanice , na przypadek cząstek Diraca. Nacisk położono na zagadnienie rozproszeniowe, do analizy którego zastosowano metodę kanałów własnych.
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Patterns of shear zones in granular bodies within a polar hypoplastic continuum
PublicationPrzedstawiono wyniki numerycznej analizy tworzenia się stref ścinania w materiałach granulowanych podczas ściskania dwuosiowego. Obliczenia wykonano stosując metodę elementów skończonych na bazie mikropolarnego hypoplsastycznego prawa materiałowego. Obliczenia wykonywano dla różnych warunków brzegowych wstępnego zagęszczenia piasku, poziomu naprężenia i rozkładu stochastycznego imperfekcji.
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J. FE modelling of cracks in concrete elements within continuum mechanics.
PublicationW artykule przedstawiono wyniki symulacji rys zakrzywionych w elementach betonowych w warunkach mieszanego sposobu obciążenia. Symulacje wykonano przy zastosowaniu 3 różnych modeli: modelu sprężysto-plastycznego, modelu w ramach mechaniki zniszczeniowej i modelu z rysami obracającymi się.
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Modelling of localization of deformation in quasi-brittle materials with a continuum and discrete model
PublicationW artykule przedstawiono wyniki obliczeń lokalizacji odkształceń w materiałach kruchych przy zastosowaniu 2 modeli w ramach mechaniki ośrodka ciągłego i jednego modelu w ramach ośrodka dyskretnego. W przypadku pierwszy zastosowano model sprężysto-plastyczny i model zniszczeniowy rozszerzony o długość charakterystyczną mikrostruktury. W przypadku drugim przyjęto model rusztowy złożony z beleczek.
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Parallelization Method for a Continuous Property
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Computer assisted method for proving existence of periodic orbits
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The Conley Index and Rigorous Numerics for Attracting Periodic Orbits
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Modelling of continuum damage for application in elasto-viscoplastic Bodner-Partom constitutive equations
PublicationW artykule zaproponowano zastosowanie modelu zniszczenia Lemaitre w sprężysto-lepkoplastycznym modelu Bodnera-Partoma. Opisane podejście jest wprowadzone do programu MSC.Marc z wykorzystaniem podprocedury UVSCPL. Przedstawiono wyniki analiz numerycznych potwierdzających przyjęte założenia.
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Comparative modelling of shear localization in granular bodies using a discrete and continuum approach
PublicationW artykule przedstawiono pierwsze wyniki symulacji rys w betonie przy zastosowaniu metody elementów dyskretnych. W obliczeniach wykorzystano program YADE. W symulacjach wykorzystano kulki o różnych średnicach. Przyjęto dodatkowo działanie momentu symulującego szorstkość ziaren.
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Modelling of strain localization in quasi-brittle materials with non-local continuum models
PublicationW artykule przedstawiono wyniki numerycznej lokalizacji odkształceń w elementach betonowych przy zastosowaniu modelu sprężysto-plastycznego i modelu z degradacja sztywności. Do opisu rys, model rozszerzono o składniki nielokalne. Obliczenia wykonano dla prostych problemów brzegowych
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SIMULATIONS OF FRACTURE IN CONCRETE BEAMS UNDER BENDING USING A CONTINUUM AND DISCRETE APPROACH
PublicationThe paper describes two-dimensional meso-scale results of fracture in notched concrete beams under bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and air voids. Within continuum mechanics, the simulations were carried out with the finite element method based on a isotropic damage constitutive model enhanced by a characteristic...
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Spin and Orbital Effects on Asymmetric Exchange Interaction in Polar Magnets: M(IO3)2 (M = Cu and Mn)
PublicationMagnetic polar materials feature an astonishing range of physical properties, such as magnetoelectric coupling, chiral spin textures, and related new spin topology physics. This is primarily attributable to their lack of space inversion symmetry in conjunction with unpaired electrons, potentially facilitating an asymmetric Dzyaloshinskii–Moriya (DM) exchange interaction supported by spin–orbital and electron–lattice coupling. However,...
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Shadowing is generic---a continuous map case
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Revisiting Supervision for Continual Representation Learning
Publication"In the field of continual learning, models are designed to learn tasks one after the other. While most research has centered on supervised continual learning, there is a growing interest in unsupervised continual learning, which makes use of the vast amounts of unlabeled data. Recent studies have highlighted the strengths of unsupervised methods, particularly self-supervised learning, in providing robust representations. The improved...
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Equivalence scales for continuous distributions of expenditure
PublicationResearch background: In the actual sizable populations of households, the standard microeconomic concept of equivalence scales is intractable since its necessary condition of equality of household welfare levels is unlikely to be fulfilled. Purpose of the article: This paper aims to develop a concept of an equivalence scale, which can be suitable for continuous distributions of expenditures in the population. Methods: Using household...
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The modelling method of discrete-continuous systems
PublicationThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...
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Hybrid Reduced Model of Continuous System
PublicationThe paper introduces an alternative method of modelling and modal reduction of continuous systems. Presented method is a hybrid one. It combines the advantages of modal decomposition method and the rigid finite element method. In the proposed method continuous structure is divided into one-dimensional continuous elements. For each 1D element modal decomposition and reduction is applied. Interactions between substructures are...
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RESHAPING THE GDANSK HARBOR –THE CONTINUOUS PROCESS
PublicationGdańsk is the harbour city with a history of more than 1000 years. For many centuries the harbour structures were evolving within the central part of the historic city centre, and – in result – a specific urban structures associated with these functions were created. But the evolution of the maritime technology as well as new needs regarding servicing the ships and cargo-handling activities effected in creation of the more modern...
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Homoclinic and Heteroclinic Orbits for a Class of Singular Planar Newtonian Systems
PublicationThe study of existence and multiplicity of solutions of differential equations possessing a variational nature is a problem of great meaning since most of them derives from mechanics and physics. In particular, this relates to Hamiltonian systems including Newtonian ones. During the past thirty years there has been a great deal of progress in the use of variational methods to find periodic, homoclinic and heteroclinic solutions...
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Connecting orbits for a periodically forced singular planar Newtonian system
PublicationW niniejszym artykule badamy problem istnienia i krotności rozwiązań homoklinicznych i heteroklinicznych dla nieautonomicznych układów Newtonowskich na płaszczyźnie z potencjałem okresowym ze względu na zmienną czasową, mającym maksimum globalne właściwe przyjmowane w dwóch punktach płaszczyzny i punkt osobliwy (studnię nieskończonej głębokości), w otoczeniu którego potencjał spełnia warunek Gordona (gradient potencjału ze względu...
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Continuum contact model for friction between graphene sheets that accounts for surface anisotropy and curvature
PublicationUnderstanding the interaction mechanics between graphene layers and co-axial carbon nanotubes (CNTs) is essential for modeling graphene and CNT-based nanoelectromechanical systems. This work proposes a new continuum contact model to study interlayer interactions between curved graphene sheets. The continuum model is calibrated and validated using molecular dynamics (MD) simulations. These are carried out employing the reactive...