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Wyniki wyszukiwania dla: system theory
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Buckling analysis of shell structures with stochastic imperfections using six parameter nonlinear shell theory
PublikacjaPrzedstawiono wpływ wstępnych losowych imperfekcji geometrycznych na wartość obciążenia krytycznego powłoki. W obliczeniach zastosowano autorski program MES wykorzystujący 6-cio parametrową nieliniową teorię powłok.
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Laminated plates and shells - first ply failure analysis within 6-parameter shell theory
PublikacjaThis work describes Tsai-Wu and Hashin criteria modifications, dictated by nonlinear 6-parameter shell theory with asymmetric strain measures and drilling rotation. The material law is based on standard orthotropic elastic constants for a non-polar continuum, under plane state of stress. First ply failure loads of cylindrical panel subjected to pressure and flat compressed plate are estimated by means of Finite Element Analysis....
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Theoretical study of the photoelectron spectrum of ethyl formate: Ab initio and density functional theory investigation
PublikacjaThe first ionization energy and associated photoelectron spectrum of ethyl formate are investigated with quantum chemistry calculations. The geometries, harmonic vibrational frequencies and first ionization energy are computed at the Hartree-Fock (HF) and at the second order Moller-Plesset perturbation theory (MP2). Moreover, accurate ionization energies are obtained with the Coupled-Cluster theory including singles and doubles...
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Drilling couples and refined constitutive equations in the resultant geometrically non-linear theory of elastic shells
PublikacjaIt is well known that distribution of displacements through the shell thickness is non-linear, in general. We introduce a modified polar decomposition of shell deformation gradient and a vector of deviation from the linear displacement distribution. When strains are assumed to be small, this allows one to propose an explicit definition of the drilling couples which is proportional to tangential components of the deviation vector....
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Application of an extended DLVO theory for the calculation of the interactions between emulsified oil droplets in alcohol solutions
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Toward an understanding of occupational burnout among employees with autism – the Job Demands‑Resources theory perspective
PublikacjaThis article aims to gain insight into the phenomenon of occupational burnout among employees with autism based on the theoretical framework of the Job Demands-Resources theory and the literature on employees with autism in the workplace. Firstly, we argue that although the resources and demands of the neurotypical and neurodivergent employees might be different, the theoretical mechanism of occupational burnout formation remains...
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Buckling Analysis of a Micro Composite Plate with Nano Coating Based on the Modified Couple Stress Theory
PublikacjaThe present study investigates the buckling of a thick sandwich plate under the biaxial non-uniform compression using the modified couple stress theory with various boundary conditions. For this purpose, the top and bottom faces are orthotropic graphene sheets and for the central core the isotropic soft materials are investigated. The simplified first order shear deformation theory (S-FSDT) is employed and the governing differential...
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Modulation of dielectric properties in low-loss polypropylene-based composites at GHz frequencies: theory and experiment
PublikacjaPolymer composites with high dielectric constant and low loss tangent are highly regarded as substrates for modern high-speed electronics. In this work, we analyze the high-frequency dielectric properties of two types of composites based on polypropylene infused with high-dielectric-constant microparticles. Two types of fillers are used: commercial ceramics or titanium oxide ( TiO2) with different concentrations. The key observation...
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Excited state properties of a series of molecular photocatalysts investigated by time dependent density functional theory.
PublikacjaTime dependent density functional theory calculations are applied on a series of molecular photocatalysts of the type [(tbbpy)2M1(tpphz)M2X2]2+ (M1 = Ru, Os; M2 = Pd, Pt; X = Cl, I) in order to provide information concerning the photochemistry occurring upon excitation of the compounds in the visible region. To this aim, the energies, oscillator strengths and orbital characters of the singlet and triplet excited states are investigated....
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Relationships between work ethic and motivation to work from the point of view of the self-determination theory
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Multiple solutions of indefinite elliptic systems via a Galerkin-type Con- ley index theory
PublikacjaW pracy wykazano prawdziwość hipotezy Angenenta i van der Vorsta dotyczącąilości rozwiązań pewnego układu eliptycznego. Liczbę rozwiazań szacuje się zdołu przy pomocy niezmiennika topologicznego zwanego uogólnionym indeksemMorse`a. W dowodzie stosuje sie niezmienniczy index Conleya w przestrzeniachHilberta.
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Analysis of the enthalpies of transfer of Co(II) ion in mixed solvents by means of the theory of preferential solvation.
PublikacjaZa pomocą teorii solwatacji preferencyjnej zanalizowano entalpie przeniesienia jonu Co(II) w kilku mieszaninach wodno-organicznych i organicznych, wyznaczając parametry, które w sposób ilościowy opisują solwatację preferencyjną jonu i jego wpływ na oddziaływania między cząsteczkami rozpuszczalnika. Przeprowadzono porównanie właściwości solwatacyjnych mieszanin. Wyznaczono także średni skład sfery solwatacyjnej jonu w zależności...
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On the theory and numerical simulation of acoustic and heat modes interaction in a liquid with bubbles: acoustic quasi-solitons
PublikacjaTeoria rzutowania zaburzenia ogólnego na mody. Zastosowanie metody do badań układu równań typu Korteweg`a-de Vries`a. Rozwiązania analityczne i simulacje numeryczne.
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Workforce mobility against the background of labour market duality theory – the example of selected OECD countries
PublikacjaThe paper aims to present an empirical study of labour market segmentation (LMS) hypothesis. According to the dual labour market theory jobs can be divided into two groups: primary and secondary jobs, with enter barriers into the first one. The primary jobs are usually described with relative high wages, whereas secondary jobs provide lower level of wages. In this paper we first examine the main sectors (according to the ISIC rev....
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On the use of enhanced strain formulation in 6-field nonlinear shell theory with asymetric strain measures
PublikacjaW pracy zbadano możliwość zastosowania techniki wzbogaconych odkształceń do usunięcia zjawiska blokady w elementach skończonych opracowanych w ramach 6-parametrowej nieliniowej teorii powłok z niesymetrycznymi miarami odkształceń membranowych. Przedstawiono i porównano 4 warianty pol wzogacających odkształcenia
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Estimation of Failure Initiation in Laminated Composites by means of Nonlinear Six-Field Shell Theory and FEM
PublikacjaThe monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...
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Multi-state multi-reference Møller-Plesset second-order perturbation theory for molecular calculations
PublikacjaThis work presents multi‐state multi‐reference Møller–Plesset second‐order perturbation theory as a variant of multi‐reference perturbation theory to treat electron correlation in molecules. An effective Hamiltonian is constructed from the first‐order wave operator to treat several strongly interacting electronic states simultaneously. The wave operator is obtained by solving the generalized Bloch equation within the first‐order...
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Airfoil Design Under Uncertainty Using Non-Intrusive Polynomial Chaos Theory and Utility Functions
PublikacjaFast and accurate airfoil design under uncertainty using non-intrusive polynomial chaos (NIPC) expansions and utility functions is proposed. The NIPC expansions provide a means to efficiently and accurately compute statistical information for a given set of input variables with associated probability distribution. Utility functions provide a way to rigorously formulate the design problem. In this work, these two methods are integrated...
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Solvation phenomena in ternary system tetramethylurea-methylacetamide-water: Insights from volumetric, compressibility and FTIR analysis
PublikacjaThe properties of the ternary systems N,N,N’,N’-tetramethylurea - N-methylacetamide - water were investigated using Fourier-transform infrared spectroscopy (FTIR), volumetric and compression measurements. Densities and sound velocities were determined in order to obtain the apparent molar volumes (VΦ) and apparent molar isentropic compressions (ΚS,Φ). These values were then extrapolated to infinite dilution. Additionally, interaction parameters...
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An analysis of observability and detectability for different sets of measured outputs - CSTR case study
PublikacjaA problem of proving the observability/detectability at a given measured output for non-linear biochemical systems has been addressed in this paper. A theory of indistinguishable state trajectories has been used to prove the properties of the observability or detectability of this system. It is related to taking system dynamics into consideration depending on initial conditions and the impact of inputs taking into account a given...
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Intelligent microbearing project with memory of stress-strain history
PublikacjaTaking into account the increasing need of intelligent micro-bearing with memory, this paper presents the optimization, simulation and practical application of operating parameters(load carrying capacity, friction forces, friction coefficient, wear), simulation for hydrodynamic HDD micro-bearing with curvilinear nano-grooved journal profile. One of the reason of such journal profile is that this journal profile contributes to the...
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Firing map of an almost periodic input function
PublikacjaIn mathematical biology and the theory of electric networks the firing map of an integrate-and-fire system is a notion of importance. In order to prove useful properties of this map authors of previous papers assumed that the stimulus function f of the system ẋ = f(t,x) is continuous and usually periodic in the time variable. In this work we show that the required properties of the firing map for the simplified model ẋ = f(t) still...
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Dynamics of S-unimodal maps used in population modeling.
Dane BadawczeS-unimodal maps are maps of the interval with negative Schwarzian derivative and having only one turning point (such that the map is increasing to the left of the turning point and decreasing to the right of it). Theory of S-unimodal maps is now a well-developed branch of discrete dynamical systems, including famous Singer theorem which implies existence...
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A study of concentration depolarization and quenching of photoluminescence of solutions
PublikacjaThe concentration-dependence of emission anisotropy r/r0 and quantum yield eta/eta0 of the photoluminescence of glycerol-water solutions of rhodamine B in two systems of viscosities 7.4 P and 0.72 P is investigated. The experimental data are compared with the new theory of concentraticn depolarization (J. Lumin., 5, 413 (1972)) and concentration quenching of photoluminescence (Acta Phys. Hungar., 30, 145 (1972)), which takes...
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TiCoCrFeMn (BCC + C14) High-Entropy Alloy Multiphase Structure Analysis Based on the Theory of Molecular Orbitals
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Data-Centric Dempster-Shafer Theory-Based Selfishness Thwarting via Trust Evaluation in MANETs and WSNs
PublikacjaPrzedstawiono ramy wymiany informacji reputacyjnej pomiędzy terminalami sieci mobilnej ad hoc lub sensorowej, prowadzące do efektywnej lokalizacji terminali egoistycznych i jednocześnie zapobiegające skutkom fałszywych rekomendacji. Integrację miar zaufania i rekomendacji reputacyjnych oparto na teorii Dempstera-Shafera.
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Theory versus experiment for vacuum Rabi oscillations in lossy cavities. II. Direct test of uniqueness of vacuum
PublikacjaThe paper continues the analysis of vacuum Rabi oscillations we started in part I [Phys. Rev. A 79, 033836 (2009)]. Here we concentrate on experimental consequences for cavity QED of two different classes of representations of harmonic-oscillator Lie algebras. The zero-temperature master equation, derived in part I for irreducible representations of the algebra, is reformulated in a reducible representation that models electromagnetic...
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Nonlinear FEM 2D failure onset prediction of composite shells based on 6-parameter shell theory
PublikacjaWithin the framework of the nonlinear 6-parameter shell theory with the drilling rotation and asymmetric stress measures, the modifications of Tsai-Wu and Hashin laminate failure initiation criteria are proposed. These improvements enable to perform first ply failure estimations taking into account the non-symmetric stress measures. In order to check the validity of the proposed criteria, finite element analyses are performed with...
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Bending and buckling formulation of graphene sheets based on nonlocal simple first-order shear deformation theory
PublikacjaThis paper presents a formulation based on simple first-order shear deformation theory (S-FSDT) for large deflection and buckling of orthotropic single-layered graphene sheets (SLGSs). The S-FSDT has many advantages compared to the classical plate theory (CPT) and conventional FSDT such as needless of shear correction factor, containing less number of unknowns than the existing FSDT and strong similarities with the CPT. Governing...
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Analytical predictions for the buckling of a nanoplate subjected to non-uniform compression based on the four-variable plate theory
PublikacjaIn the present study, the buckling analysis of the rectangular nanoplate under biaxial non-uniform compression using the modified couple stress continuum theory with various boundary conditions has been considered. The simplified first order shear deformation theory (S-FSDT) has been employed and the governing differential equations have been obtained using the Hamilton’s principle. An analytical approach has been applied to obtain...
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Application of potential theory in calculating wave-induced vertical forces on horizontal cylinders near a plane boundary
PublikacjaHydrodynamiczne obciażenia wywołane falowaniem morskim działajace na poziomo ułożoną przy dnie rurę, rozpatrywane są w ujęciu dyfrakcyjnym przy założeniu istnienia funkcji potencjału. Potencjał zdefiniowano jako superpozycję potencjału fali inicjującej oraz potencjału perturbacji spowodowanej istnieniem obiektu przy dnie. Wyniki rozwiązań teoretycznych porównano z wynikami doswiadczeń przeprowadzonych w Wielkim Kanale falowym w...
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Bridging theory and practice in postgraduate education on development and planning: Gdynia Urban Summer Schools 2016-2018
PublikacjaIn this article, the authors discuss results achieved by the Gdynia Urban Summer School (GUSS) organised annually (between 2016 and 2018) in Gdynia, Poland. The GUSS was meant for young practitioners from various professions such as urban and regional planning, urban design, architecture, civil engineering and transport planning. The objective was to give workshop participantspractical interdisciplinary...
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Markowitz’s portfolio theory – optimal length of estimation window for gold and the biggests companies on the Warsaw Stock Exchange
PublikacjaThe following article is dedicated to the construction of an investment portfolio consisting of 3 investments from the Polish capital market found in the WIG20 index and from investment in gold. The purpose of the study was to determine the optimal length of the estimation window for building a portfolio with minimal risk and maximum efficiency. The length of the estimation window was also assessed in terms of the rate of return...
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Recent Achievements in Constitutive Equations of Laminates and Functionally Graded Structures Formulated in the Resultant Nonlinear Shell Theory
PublikacjaThe development of constitutive equations formulated in the resultant nonlinear shell theory is presented. The specific features of the present shell theory are drilling rotation naturally included in the formulation and asymmetric measures of strains and stress resultants. The special attention in the chapter is given to recent achievements: progressive failure analysis of laminated shells and elastoplastic constitutive relation...
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Two- and three-dimensional elastic networks with rigid junctions: modeling within the theory of micropolar shells and solids
PublikacjaFor two- and three-dimensional elastic structures made of families of flexible elastic fibers undergoing finite deformations, we propose homogenized models within the micropolar elasticity. Here we restrict ourselves to networks with rigid connections between fibers. In other words, we assume that the fibers keep their orthogonality during deformation. Starting from a fiber as the basic structured element modeled by the Cosserat...
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Application of Biot’s theory to ultrasonic characterization of human cancellous bones: Determination of structural, material, and mechanical properties
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Application of the theory of energy transformation systems to fatigue assessment of steel elements under multiaxial periodic loading
PublikacjaPraca dotyczy symulacji odporności zmęczeniowej elementów stalowych poddanych wieloosiowym obciążeniom okresowym w zakresie wysokocyklowym. W tym celu zdefiniowano jednoosiowe naprężenie sinusoidalne, równoważne w sensie trwałości zmęczeniowej materiału naprężeniu aktualnemu gdy każda jego kartezjańska składowa jest dana w postaci szeregu Fouriera. Warunki równoważności wynikają z teorii systemów transformacji energii i wiążą się...
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Equivalent 4-node enhanced assumed strain and hybrid stress shell elements in 6-parameter theory
PublikacjaWe discuss the equivalence of semi-enhanced assumed strain (EAS) and semi-hybrid stress (SEM) shell finite elements. We use the general nonlinear 6-field shell theory with kinematics composed of generalized displacements composed of the translation field and the rotation field. Due to the presence of rotation tensor the elements have naturally six nodal engineering degrees of freedom. We propose interpolation for a strain field...
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Determination of the thermal conductivity of material dividing the metallic core elements of the bi-calorimeter using modified theory
PublikacjaW pracy przedstawiono zmodyfikowaną teorię bikalorymetru z dzielonym metalowym rdzeniem. Pomiędzy dwiema częściami rdzenia umieszczano próbki badanego ciała stałego lub gazu. Ogrzewano jedną stronę rdzenia. Mierzono temperaturę obu części rdzenia w funkcji czasu. Uzyskane wyniki umożliwiły wyznaczenie różnicy temperatur i strumienia ciepła, przepływającego przez próbkę. Z zastosowaniem prawa Fouriera obliczano współczynnik przewodności...
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The atlas of inequality aversion: theory and empirical evidence on 55 countries from the Luxembourg Income Study database
PublikacjaResearch background: In the distributive analysis, the constant relative inequality aversion utility function is a standard tool for ethical judgements of income distributions. The sole parameter ε of this function expresses a society’s aversion to inequality. However, the profession has not committed to the range of ε. When assessing inequality and other welfare characteristics, analysts assume an arbitrary level of ε, common...
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Network design for surface water quality monitoring in a road construction project using Gamma Test theory
PublikacjaRoad construction has a negative environmental impact on the surrounding aquatic environment, requiring the continuous monitoring of surface water quality. Here, optimization of the water quality monitoring network (WQMN) is an essential step in supporting the sustainable development of road construction projects. This study introduces Gamma Test theory (GTT) as a practical method for optimizing the WQMN of surface waters during...
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Interpretation and modeling of emotions in the management of autonomous robots using a control paradigm based on a scheduling variable
PublikacjaThe paper presents a technical introduction to psychological theories of emotions. It highlights a usable ideaimplemented in a number of recently developed computational systems of emotions, and the hypothesis thatemotion can play the role of a scheduling variable in controlling autonomous robots. In the main part ofthis study, we outline our own computational system of emotion – xEmotion – designed as a key structuralelement in...
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PROBLEMY RACJONALNEGO ZASTOSOWANIA SYSTEMÓW DIAGNOZUJĄCYCH DO PODEJMOWANIA DECYZJI W FAZIE EKSPLOATACJI URZĄDZEŃ ENERGETYCZNYCH Z UWZGLĘDNIENIEM ZAGADNIEŃ KWANTOWYCH
PublikacjaW rozdziale przedstawiono najistotniejsze problemy pojawiające się w fazie projektowania, wytwarzania i eksploatacji systemów diagnozujących (SDG) urządzeń energetycznych (będących systemami diagnozowanymi – SDN), w przypadku przysposabiania ich do opracowania finalnej diagnozy eksploatacyjnej. Przestawiono opisową i formalną interpretację pojęcia systemu diagnozującego (SDG). Zaproponowano modele procesu diagnozowania urządzeń...
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3-D Printable Metal-Dielectric Metasurface for Risley Prism-Based Beam-Steering Antennas
PublikacjaA 3-D printable, planar, metal-dielectric metasurface-based, 2-D beam-steering system for aperture-type antennas is presented in this paper. This beam steering system, also known as the near-field meta-steering system, comprises two fully passive phase-gradient metasurfaces placed in the antenna’s nearfield region to steer the radiation beam. To address the non-uniform electric field phase of the aperture antenna, phase correction...
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Book Review: Vishwas Satgar (ed.), The Solidarity Economy Alternative: Emerging Theory and PracticeSatgarVishwas (ed.), The Solidarity Economy Alternative: Emerging Theory and Practice, University of KwaZulu-Natal Press: Durban, 2014; 332 pp.: ISBN 9781869142575, US$34.44
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DIFFRACTION PHASE MICROSCOPY FOR OBSERVATION ON RED BLOOD CELLS FLUCTUATION
PublikacjaNowadays there is quite huge need for more and more precise and effective fast diagnostics methods in hematology diseases. One of the most important blood components are erythrocytes – RBCs (Red Blood Cells). Due to their size they are easy to observe using microscopy. It is commonly known that the shape and lifetime of RBCs allows for early disease identification. Authors present special measurement system for RBCs fluctuations observation...
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Evaluation of Decision Fusion Methods for Multimodal Biometrics in the Banking Application
PublikacjaAn evaluation of decision fusion methods based on Dempster-Shafer Theory (DST) and its modifications is presented in the article, studied over real biometric data from the engineered multimodal banking client verification system. First, the approaches for multimodal biometric data fusion for verification are explained. Then the proposed implementation of comparison scores fusion is presented, including details on the application...
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Analytical Buckling of FG Nanobeams on The Basis of A New One Variable First-Order Shear Deformation Beam Theory
PublikacjaIn this work, buckling analysis of functionally graded (FG) nanobeams based on a new refined beam theory has been analyzed. The beam is modeled as an elastic beam subjected to unidirectional compressive loads. To achieve this aim, the new obtained beam theory has only one variable which leads to one equation similar to the Euler beam theory and also is free of any shear correction factor. The equilibrium equation has been...
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Density Functional Theory Studies on Ir Spectra of the Triphenylene Derivatives. A Scaled Quantum Mechanical Force Field Approach
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Analytical Buckling of FG Nanobeams on The Basis of A New One Variable First-Order Shear Deformation Beam Theory
PublikacjaIn this work, buckling analysis of functionally graded (FG) nanobeams based on a new refined beam theory has been analyzed. The beam is modeled as an elastic beam subjected to unidirectional compressive loads. To achieve this aim, the new obtained beam theory has only one variable which lead to one equation similar to Euler beam theory and also is free of any shear correction factor. The...