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Search results for: SIMILITUDE LAWS
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Viscoplastic damage analysis of structures subjected to impact loading. Plate and shell structures. - Ł. Pyrzowski.
PublicationThe work presents the investigation in the response of plate-shell structures subjected to impact loading (gas mixture explosions). This phenomenon is studied in the context of its mechanical aspects, mainly the ductile fracture prediction. The work starts with the literature review and the description of theories, which are nowadays the most popular in the damage and failure modelling. After selecting the theoretical models and...
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ARRAY OF MINIJETS – THERMAL AND HYDRAULIC PHENOMENA IN BOUNDARY LAYER
PublicationPresented work considers flow and thermal phenomena occurring in the system consisting of minijets array and heated with constant heat flux surface. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted. Focus was placed on the proper model construction, in which turbulence and boundary layer modelling was crucial. Calculations were done for various mass flow rates. The main calculations were...
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Structural response of existing spatial truss roof construction based on Cosserat rod theory
PublicationPaper presents the application of the Cosserat rod theory and newly developed associated finite elements code as the tools that support in the expert-designing engineering practice. Mechanical principles of the 3D spatially curved rods, dynamics (statics) laws, principle of virtual work are discussed. Corresponding FEM approach with interpolation and accumulation techniques of state variables are shown that enable the formulation...
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Turbulence models impact on the flow and thermal analyses of jet impingement
PublicationAccurate numerical reconstruction of heat and mass transfer processes in particular applications, such a jet impingement, is difficult to obtain even with the use of modern computational methods. In the proposed paper, the flow and thermal phenomena occurring during single minijet impingement on the flat, concave and convex, heated surfaces were considered. Problem of impingement on non-flat surface, still not common and purely...
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Determination of Biogenic Amines in Wine Using Micellar Electrokinetic Chromatography
PublicationProduction on a large-scale of fermented alcoholic drinks made from different kinds of fruits is carried out in homes. Although wine laws regulating home production exist, they do not include upper concentration limits of biogenic amines. Therefore, a quick and inexpensive way to determine BAs in wine is crucial. A new analytical method based on micellar electrokinetic chromatography has been developed for the separation of the...
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Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
PublicationIn the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens...
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A Review of Hyperelastic Constitutive Models for Dielectric Elastomers
PublicationDielectric elastomers are smart materials that are essential components in soft systems and structures. The core element of a dielectric elastomer is soft matter, which is mainly rubber-like and elastomeric. These soft materials show a nonlinear behaviour and have a nonlinear strain-stress curve. The best candidates for modelling the nonlinear behaviour of such materials are hyperelastic strain energy functions. Hyperelastic functions...
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The role of stakeholders on rejection of bankruptcy applications in the case of “poverty” of the estate: A Polish case study
PublicationThe aim of this article is to supplement the Law and Economics area of science with regard to the scope of the ex ante effectiveness of bankruptcy law using the example of Poland. Bankruptcy law is effective in the ex ante stage when it eliminates from the market insolvent entrepreneurs who cannot even afford to cover the costs of bankruptcy proceedings. In these cases, the bankruptcy court should dismiss the petition for bankruptcy...
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Mode vibrations of plates – experimental analysis
PublicationIn this paper results of the square MDF plate and circular saw blades examination with the use of the harmonic method to static identification of resonant frequencies and shapes of mode vibrations are presented. Obtained results reveled that for circular saws with large holes in a saw blade appeared two resonant frequencies for the same nodal number.
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Utilization of shale cuttings in production of lightweight aggregates
PublicationThe development of technologies for unconventional hydrocarbon exploration requires designing procedures to manage drilling waste that are consistent with the waste management hierarchy. In view of this, the possibility to apply shale drill cuttings as a prospective additive (replacing bentonite) to fly ash used for the production of lightweight aggregates (LWAs) was investigated. Moreover, a facile, waste-free method of LWAs production...
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Geometrically Nonlinear Analysis of Functionally Graded Shells Based on 2-D Cosserat Constitutive Model
PublicationIn this paper geometrically nonlinear analysis of functionally graded shells in 6-parameter shell theory is presented. It is assumed that the shell consists of two constituents: ceramic and metal. The mechanical properties are graded through the thickness and are described by power law distribution. Formulation based on 2-D Cosserat constitutive model is used to derive constitutive relation for functionally graded shells. Numerical...
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Elastoplastic nonlinear FEM analysis of FGM shells of Cosserat type
PublicationThe paper is a continuation of [1] where the formulation of the elastic constitutive law for functionally graded materials (FGM) on the grounds of nonlinear 6-parameter shell theory with the 6th parameter (the drilling degree of freedom) was presented. Here the formulation is extended to the elasto-plastic range. The material law is based on Cosserat plasticity and employs the well-known Tamura-Tomota-Ozawa (TTO) [2] mixture...
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Analysis of the design development of the sliding table saw spindles
PublicationProducers of sliding table saws constantly strive for improvement in sawing accuracy. One of the method is an upswing in a spindle behavior, since, it affects to a large degree sawing effects. The design development of sliding table saw spindles during the last quarter-century is presented. The spindle system of the modernized spindle of the sawing machine Fx550 is described.
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Technological Problems in Lapping on Flat Surfaces of Ceramic Parts
PublicationThis paper will present the results of research on single-disc lapping of flat surfaces of small ceramic elements. Machining with the use of different tools such as metallic, two-metallic and abrasive-metallic will be analyzed. The basics and techniques of reinforcement of laps will be discussed. The results of the influence of parameters on the surface quality of ceramic conponents (sealing) for three treatments on lapping machines...
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Realistic noise-tolerant randomness amplification using finite number of devices
PublicationRandomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification...
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Dynamics of Chains as a Tool to Study Thermomechanical Properties of Proteins.
PublicationPolymer dynamics can be formulated on different levels of detail. One approach eliminates microscopic degrees of freedom and a polymer molecule is represented by a simplified structure—a chain. In the simplest case monomers of ideal chain have fixed length, and their orientation is independent of the orientations and positions of neighbouring monomers. This is reason that two monomers can co-exist at the same place. Ideal chain...
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Protocolo de Preparación y Evaluación de Pilas de Combustible de Óxido Sólido
PublicationEste protocolo describe la metodología para la preparación de celdas de óxido sólido y su evaluación como pila de combustible (SOFC). Es fruto del estudio realizado en el marco de los proyectos FCTESTNET [1] y SOFCNET [2] del V Programa Marco, en el Comité IEC/TC105 [3] e investigaciones llevadas a cabo en el laboratorio. Las pilas de combustible son dispositivos capaces de transformar la energía química de un combustible en energía...
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Limits Theorems for Random Walks on Homeo(S1)
PublicationThe central limit theorem and law of the iterated logarithm for Markov chains corresponding to random walks on the space Homeo(S1) of circle homeomorphisms for centered Lipschitz functions and every starting point are proved.
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Information Processing and Fechner’s Problem as a Choice of Arithmetic
PublicationFechner’s law and its modern generalizations can be regarded as manifestations of alternative forms of arithmetic, coexisting at stimulus and sensation levels. The world of sensations may be thus described by a generalization of the standard mathematical calculus.
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RUSSIANS ON THE POLISH LABOUR MARKET
PublicationThe article looks into the employment of Russian citizens in Poland in 2004– 2018. It presents the legal basis for Russians’ entering Poland and taking up work without having to seek a work permit, and specifies who must apply for such a permit. Russian citizens can obtain refugee status under the Geneva Convention, which grants them the right to move freely, choose their place of residence and undertake paid employment, while...
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Determinants of judges’ career choices and productivity: a Polish case study
PublicationThe goal of this paper is to identify factors which affect judges’ productivity and career choice motives with the view of increasing judicial efficiency. Specifically, the investigation focuses on such aspects as judges’ remuneration, promotion, threat of judgment revocation, service/mission, periodic assessment, the threat of a complaint about protracted proceedings or of disciplinary proceedings, the threat of destabilization...
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The effect of Ru substitution for Ni on the superconductivity in MgCNi_(3-x)Ru_x
PublicationW pracy prezentowane są pomiary podatności magnetycznej i ciepła właściwego domieszkowanego nadprzewodnika MgCNi_(3-x)Ru_x. Wraz ze wzrostem koncetracji Ru współczynnik Sommerfelda, jak również temperatura krytyczna (T_c) maleją, co stoi w sprzeczności z teoretycznymi oczekiwaniami.
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Effect of Ru substitution for Ni on the superconductivity inMgCNi3−xRux
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Active Control of Highly Autocorrelated Machinery Noise in Multivariate Nonminimum Phase Systems
PublicationIn this paper, a novel multivariate active noise control scheme, designed to attenuate disturbances with high autocorrelation characteristics and preserve background signals, is proposed. The algorithm belongs to the class of feedback controllers and, unlike the popular feedforward FX-LMS approach, does not require availability of a reference signal. The proposed approach draws its inspiration from the iterative learning control...
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Secure Quaternion Feistel Cipher for DICOM Images
PublicationAn improved and extended version of a quaternion-based lossless encryption technique for digital image and communication on medicine (DICOM) images is proposed. We highlight and address several security flaws present in the previous version of the algorithm originally proposed by Dzwonkowski et al. (2015). The newly proposed secure quater- nion Feistel cipher (S-QFC) algorithm...
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KOMPUTER W LABORATORIUM VS LABORATORIUM W KOMPUTERZE
PublicationAbstract. In March 2020, all of the sudden, university teachers have been made to run all the classes remotely. But, how to deal with lab classes for future engineers? Different aspects of teaching labs on Moodle, that should be taken in consideration, are not only connected with the content of the class, but also with transferring the knowledge and materials to the students in a way that would avoid distractions and help students...
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The safety issue of roadside advertising – comparison of polish and abu dhabi regulations
PublicationIn Poland a large number of advertisements are located by the roadside. These ads do not support road traffic management and unlike the road marking system are not subject to any regulations. The advertiser’s goal is to communicate a message to as many recipients as possible. Drivers with different individual abilities, such as attention focusing, eye accommodation, speed of information processing, can be distracted, blinded or...
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Thermal and hydraulic phenomena in boundary layer of minijets impingement on curved surfaces
PublicationPresented work considers flow and thermal phenomena occurring during the single minijet impingement on curved surfaces, heated with a constant heat flux, as well as the array of minijets. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted, regarding single phase and two-phase simulations. Focus was placed on the proper model construction, in which turbulence and boundary layer modeling...
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An isogeometric finite element formulation for frictionless contact of Cosserat rods with unconstrained directors
PublicationThis paper presents an isogeometric finite element formulation for nonlinear beams with impenetrability constraints, based on the kinematics of Cosserat rods with unconstrained directors. The beam cross-sectional deformation is represented by director vectors of an arbitrary order. For the frictionless lateral beam-to-beam contact, a surface-to-surface contact algorithm combined with an active set strategy and a penalty method...
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Wykorzystanie laserowego analizatora dyfrakcyjnego do badania zmian w strukturze osadu czynnego pod wpływem surfaktantu
PublicationWykonane analizy pozwoliły stwierdzić, że metoda dyfrakcji laserowej jest metodą, którą można wykorzystać do określenia rozkładu wielkości cząstek osadu czynnego a także śledzić zmiany dokonujące się w osadzie pod wpływem zmieniających się warunków oczyszczania ścieków. Obecność surfaktantu anionowego LAS przyczyniła się do zmiany dystrybucji rozmiarów kłaczków. Stężenie surfaktantu LAS niższe od 200 mg/dm3 w osadzie powodowało...
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Rozważania nad procesem stanowienia prawa w Polsce i Chinach na przestrzeni wieków. Wybrane zagadnienia
PublicationNiniejsza monografia jest zbiorem rozdziałów poświęconych zarówno historii prawa polskiego, jak i prawa chińskiego. Zakreślone w ten sposób szerokie pole badawcze umożliwiło tym samym zróżnicowany przegląd rozważań nad procesem stanowienia prawa w Polsce i Chinach na przestrzeni wielu wieków. Zakres tematyczny poszczególnych rozdziałów jest odzwierciedleniem prowadzonych badań oraz zainteresowań naukowych poszczególnych autorów...
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Transformation of the Perpetual Usufruct Right Into the Ownership of a Real Property Estate
PublicationIn addition to the ownership, there is in Poland the so-called perpetual usufruct right, which is an intermediate form between ownership and limited property rights. It allows for long-term use of the land which is not our ownership. Makes it possible to mortgage a property, is transferable and inheritable. The article describes the legal regulations governing the establishment and functioning of the perpetual usufruct, and the...
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Determination of 3,4-methylenedioxy-α-pyrrolidinobutiophenone (MDPB) in blood. A case report
PublicationSynthetic drugs, known as ‘‘legal highs’’, are still very popular on black market. The determination of their composition are required in courts of law and also to understand what potential users may be subjected to. The interest of new cathinones, e.g. MDPBP, is in view of psychoactive effects that they cause and that, in many cases, they are not controlled by law. The case outlined here concerns 19 years-old man, who was found...
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ADAPTIVE BACKSTEPPING TRACKING CONTROL FOR OVER-ACTUATED DP MARINE VESSEL WITH INERTIA UNCERTAINTIES
PublicationDesigning a tracking control system for an over-actuated dynamic positioning marine vessel in the case of insufficient information on environmental disturbances, hydrodynamic damping, Coriolis forces and vessel inertia characteristics is considered. The designed adaptive MIMO backstepping control law with control allocation is based on Lyapunov control theory for cascaded systems to guarantee stabilization of the marine vessel...
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UK travel agents’ evaluation of eLearning courses offered by destinations: an exploratory study.
PublicationThis study aims to develop an understanding of the use of e-learning courses created for travel agents by Destination Management Organizations (DMOs). It explores agents’ perceptions of such courses. The research examines the views of 304 UK-based travel agents using online survey and investigates whether age, sex, type of agency, work experience, and educational level have influence on e-learning uptake. The satisfaction of travel...
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Recent Advances in Loop Heat Pipes with Flat Evaporator
PublicationThe focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle)...
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Assessment of Trace Metals Leaching During Rainfall Events from Building Rooftops with Different Types of Coverage – Case Study
PublicationRunoff water is an important medium transporting various types of pollution originating from the atmosphere and washed out from roofing materials. The study presents a quality assessment of runoff from different roofs in the context of trace metal concentrations. The analysed rooftops were covered with copper, tar paper and ceramic tile. The quality of the rain water collected at the same time satisfies the demands of the first...
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The effect of anionic surfactant concentration on activated sludge condition and phosphate release in biological treatment plant
PublicationThis paper discusses the influence of a wide range of anionic surfactant concentrations on activated sludge. Linear alkylbenzene sulphonate (LAS) was chosen as an example of a commonly used anionic surfactant. The fate of the surfactant during biological treatment of wastewater was tested. The effect of surfactant on glucose and starch removal was studied.
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Hydration of Oxometallate Ions in Aqueous Solution
PublicationThe strength of hydrogen bonding to and structure of hydrated oxometallate ions in aqueous solution have been studied by double difference infrared (DDIR) spectroscopy and large-angle X-ray scattering (LAXS), respectively. Anions are hydrated by accepting hydrogen bonds from the hydrating water molecules. The oxygen atom of the permanganate and perrhenate ions form weaker and longer hydrogen bonds to water than the hydrogen bonds...
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Thermal ablation modeling via the bioheat equation and its numerical treatment
PublicationThe phenomenon of thermal ablation is described by Pennes’ bioheat equation. This model is based on Newton’s law of cooling. Many approximate methods have been considered because of the importance of this issue. We propose an implicit numerical scheme which has better stability properties than other approaches.
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Energy Consumption Analysis Methods in Industry
PublicationThis paper overviews applied methods to evaluate energy consumption in Industry. The most important law regulations are presented, which decide on the necessity to conduct an effec - tive energetic economy. Basic assumptions are defined to calculate direct and cumulative energy consumption. The pros and cons of using each method are presented.
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On the production of electricity in Poland using a geothermal binary power plant - A thermodynamic overview - Part I
PublicationPoland has a significant potential of geothermal energy. However, the high-temperature sources that are needed to drive power plants are found in relatively few places. Therefore, the objective of this paper is to consider any location in the northern part of Poland as a possible place to build a binary power plant. A scientific research was confirmed the existence of an elevated temperature gradient in this region. The hot rocks...
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Low temperature processed MnCo2O4 and MnCo1.8Fe0.2O4 as effective protective coatings for solid oxide fuel cell interconnects at 750 °C
PublicationIn this study two materials, MnCo2O4 and MnCo1.8Fe0.2O4 are studied as potential protective coatings for Solid Oxide Fuel Cell interconnects working at 750 °C. First powder fabrication by a modified Pechini method is described followed by a description of the coating procedure. The protective action of the coating applied on Crofer 22 APU is evaluated by following the area specific resistance (ASR) of the scale/coating for 5500...
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Nickel Oxide Thin Film Sensor for Fluctuation-Enhanced Gas Sensing of Formaldehyde
PublicationNanocrystalline nickel-oxide-based thin films were prepared by advanced reactive gas deposition, and the response of these films to formaldehyde was studied by fluctuationenhanced sensing. Morphological and structural analyses showed porous deposits of nickel oxide particles with face-centered cubic structure. Resistance fluctuations were measured upon exposure to ethanol, formaldehyde and methane at 200 °C. Power density spectra...
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Fluctuation-enhanced and conductometric gas sensing with nanocrystalline NiO thin films: A comparison
PublicationNanocrystalline thin films of NiO were prepared by advanced reactive gas deposition, and their responses to formaldehyde, ethanol and methane gases were studied via fluctuation-enhanced and conductometric methods Thin films with thicknesses in the 200–1700-nm range were investigated in as-deposited form and after annealing at 400 and 500 °C. Morphological and structural analyses showed porous deposits with NiO nanocrystals having...
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Thick - film and LTCC multicontact resistors - preliminary results
PublicationW artykule zaprezentowano i skomentowano wstępne wyniki elektryczxnych i geometrycznych charakterystyk wielokontaktowychstruktur rezystywnych wykonanych w technologiigrubowarstwowej i LTCC ( ceramicznej z niską temperatura wypadaniz). Realizowane struktury miały rozmiary od 200 x 100 μm2 do 1500 x 500 μm2 i 3 lub 6 kontaktów rozmieszczonych e różny sposób na obwodzie warstwy rezystywnej.
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Real-time simulator of agricultural biogas plant
PublicationThis article presents a real-time simulator of an agricultural biogas plant. The project contains biogas and biomass circuits simulation, as well as heating circuit simulation with a complete control system and visualization interface of the whole process. The software tool used to simulate the plant work is CFD (Computational Fluid Dynamics), which enables a user to create and test simulation objects based on fundamental physical...
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Old-timer Vehicle - Braking Efficiency Measurement at Vehicle Inspection Stations and Roadworthiness Validity Certificate.
PublicationObtaining the Roadworthiness Validity Certificate for an old-timer vehicle involves an appropriate test performance, namely, "Old-timer Vehicle Technical Specification Compliance Test". It seems obvious that this kind of test should include a considerable checklist, however, the current legal regulations connected with this test are not specific enough. One of the certificates issued on this test results is "Old-timer Vehicle Technical...
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A model of damaged media used for describing the process of non-stationary creep and long-term strength of polycrystalline structural alloys
PublicationThe main laws of the processes of creep and long-term strength of polycrystalline structural alloys are considered. From the viewpoint of continuum damaged media (CDM), a mathematical model is developed that describes the processes of viscoplastic deformation and damage accumulation under creep. The problem of determining material parameters and scalar functions of the developed constitutive relations based on the results of specially...
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Surface effects of network materials based on strain gradient homogenized media
PublicationThe asymptotic homogenization of periodic network materials modeled as beam networks is pursued in this contribution, accounting for surface effects arising from the presence of a thin coating on the surface of the structural beam elements of the network. Cauchy and second gradient effective continua are considered and enhanced by the consideration of surface effects. The asymptotic homogenization technique is here extended to...