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Search results for: CREEP PRE-DEFORMATION
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Serendipitous Recommendations Through Ontology-Based Contextual Pre-filtering
PublicationContext-aware Recommender Systems aim to provide users with better recommendations for their current situation. Although evaluations of recommender systems often focus on accuracy, it is not the only important aspect. Often recommendations are overspecialized, i.e. all of the same kind. To deal with this problem, other properties can be considered, such as serendipity. In this paper, we study how an ontology-based and context-aware...
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Numerical solutions for large deformation problems in geotechnical engineering
PublicationThe problem of large deformations often occurs in geotechnical engineering. Numerical modeling of such issues is usually complex and tricky. The chosen solution has to implicate soil-soil and soil-structure interactions. In this paper, a review of the most popular numerical methods for large deformation problems is presented. The Coupled Eulerian-Lagrangian (CEL) method, the Arbitrary Lagrangian-Eulerian (ALE) method, the Smoothed...
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Optical flow method for measuring deformation of soil specimen subjected to torsional shearing
PublicationIn this study optical flow method was used for soil small deformation measurement in laboratory tests. The main objective was to observe how the deformation distributes along the whole height of cylindrical soil specimen subjected to torsional shearing (TS test). The experiments were conducted on dry non-cohesive soil specimens under two values of isotropic pressure. Specimens were loaded with low-amplitude cyclic torque to analyze...
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Fermentative Conversion of Two-Step Pre-Treated Lignocellulosic Biomass to Hydrogen
PublicationFermentative hydrogen production via dark fermentation with the application of lignocellulosic biomass requires a multistep pre-treatment procedure, due to the complexed structure of the raw material. Hence, the comparison of the hydrogen productivity potential of different lignocellulosic materials (LCMs) in relation to the lignocellulosic biomass composition is often considered as an interesting field of research. In this study,...
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublicationThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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Stiffness of cold-recycled mixtures under variable deformation conditions in the IT-CY test
PublicationStiffness modulus belongs to the most important properties describing the cold-recycled mixtures (CRM) in terms of their usability in road pavement structures. Previous research proved that this property is strongly dependent on the scheme and conditions of the test (temperature and time of loading) and the time that has passed since the compaction of the specimen or pavement layer. It is a result of the influence of two different...
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Fast Design Optimization of Waveguide Filters Applying Shape Deformation Techniques
PublicationThis paper presents an efficient design of microwave filters by means of geometry optimization using shape deformation techniques. This design procedure allows for modelling complex 3D geometries which can be fabricated by additive manufacturing (AM). Shape deforming operations are based on radial basis function (RBF) interpolation and are integrated into an electromagnetic field simulator based on the 3D finiteelement method (FEM)....
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An Ontology-based Contextual Pre-filtering Technique for Recommender Systems
PublicationContext-aware Recommender Systems aim to provide users with the most adequate recommendations for their current situation. However, an exact context obtained from a user could be too specific and may not have enough data for accurate rating prediction. This is known as the data sparsity problem. Moreover, often user preference representation depends on the domain or the specific recommendation approach used. Therefore, a big effort...
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Influence of accelerometer signal pre-processing and classification method on human activity recognition
PublicationA study of data pre-processing influence on accelerometer-based human activity recognition algorithms is presented. The frequency band used to filter-out the accelerometer signals and the number of accelerometers involved were considered in terms of their influence on the recognition accuracy. In the test four methods of classification were used: support vector machine, decision trees, neural network, k-nearest neighbor.
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Local variance factors in deformation analysis of non-homogenous monitoring networks
PublicationThis paper proposes a modification of the classical deformation analysis algorithm for non-homogeneous (e.g. linear-angular) monitoring networks. The basis for the proposed solution is the idea of local variance factors. The theoretical discussion was complemented with an example of its application on a simulated horizontal monitoring network. The obtained results confirm the usefulness of the proposed solution.
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GPU-Accelerated 3D Mesh Deformation for Optimization Based on the Finite Element Method
PublicationThis paper discusses a strategy for speeding up the mesh deformation process in the design-byoptimization of high-frequency components involving electromagnetic field simulations using the 3D finite element method (FEM). The mesh deformation is assumed to be described by a linear elasticity model of a rigid body; therefore, each time the shape of the device is changed, an auxiliary elasticity finite-element problem must be solved....
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Probabilistic estimation of diverse soil condition impact on vertical axis tank deformation
PublicationThe calculations of fuel tanks should take into account the geometric imperfections of the structure as well as the variability of the material parameters of the foundation. The deformation of the tank shell can have a significant impact on the limit state of the structure and its operating conditions. The paper presents a probabilistic analysis of a vertical-axis, floating-roof cylindrical shell of a tank with a capacity of 50000...
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Pre-treatment of bio fraction waste prior to fermentation processes
PublicationCurrent efforts are taken to increase resource efficiency, close material loops, and improve sustainable waste and by-products management. Thus, networking agro-food by-products and converting them into valuable products completely exhausting the potential of the raw material becomes significant. Model lignocellulosic and starch based biomass were subjected to pre-treatment with the application of acidic compounds, i.e. sulphuric...
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An experimental investigation of the influence of plasticity on creep degradation rate
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An experimental investigation of the influence of plasticity on creep degradation rate
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Analysis of Excavation-induced Deformation with Different Soil Models
PublicationMonitorowany wykop budowlany w centrum Warszawy poddano symulacjom numerycznym z wykorzystaniem metody elementów skończonych. Wykop zrealizowany został w pre-konsolidowanych utworach spoistych z zastosowaniem ścian szczelinowych i metody stropowej. Szczególnie ważny w symulacjach tego rodzaju zagadnień jest wybór modelu zachowania się gruntu w warunkach małych odkształceń przed osiągnięciem zniszczenia. Opis aktualnej sztywności...
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Large deformation finite element analysis of undrained pile installation
PublicationIn this paper, a numerical undrained analysis of pile jacking into the subsoil using Abaqus software suit has been presented. Two different approaches, including traditional Finite Element Method (FEM) and Arbitrary Lagrangian–Eulerian (ALE) formulation, were tested. In the first method, the soil was modelled as a two-phase medium and effective stress analysis was performed. In the second one (ALE), a single-phase medium was assumed...
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Selection of an artificial pre-training neural network for the classification of inland vessels based on their images
PublicationArtificial neural networks (ANN) are the most commonly used algorithms for image classification problems. An image classifier takes an image or video as input and classifies it into one of the possible categories that it was trained to identify. They are applied in various areas such as security, defense, healthcare, biology, forensics, communication, etc. There is no need to create one’s own ANN because there are several pre-trained...
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Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
PublicationInfluence of two factors: the variable cross-section and the localized plastic deformation, which affect the stray magnetic field profile of a ferromagnetic sample have been studied. Evaluation of an effect size is based on the analysis of the stray magnetic field component which is tangential to the longest dimension of a sample. However, in order to describe the nature of the stray magnetic field, the normal component (perpendicular...
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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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Comparison and Optimization of Saccharification Conditions of Alkaline Pre-Treated Triticale Straw for Acid and Enzymatic Hydrolysis Followed by Ethanol Fermentation
PublicationThis paper concerns the comparison of the efficiency of two-stage hydrolysis processes, i.e., alkaline pre-treatment and acid hydrolysis, as well as alkaline pre-treatment followed by enzymatic hydrolysis, carried out in order to obtain reducing sugars from triticale straw. For each of the analyzed systems, the optimization of the processing conditions was carried out with respect to the glucose yield. For the alkaline pre-treatment,...
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Pre-feasibility study for treatment wetland application for wastewater treatment in dispersed development
PublicationThe aim of the paper is to present the conducted analyses of pre-feasibility study of different approaches for wastewater management in a settlement of 180 persons. In the assessment both technical and economic aspects were analyzed. The costs were calculated for three different and, at the same time, most popular as well as possible technical solutions like: (i) construction of local wastewater treatment plant with gravitational...
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A role of destructive and non-destructive tests in creep damage Identification
PublicationPrzedstawiono wyniki badań mjących zilustrować i określić rolę badań niszczących i nieniszczących w identyfikowaniu degradacji po pełzaniu
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Equivalent single-layer models in deformation analysis of laminated multilayered plates
PublicationThe performance of selected Equivalent Single-Layer (ESL) models is evaluated within several classical benchmark tests for linear static analysis of multi-layered plates. The authors elaborated their own Finite Element software based on the first-order shear deformation theory (FOSD) with some modifications incorporated including a correction of the transverse shear stiffness and an application of zig-zag type functions. Seven...
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Influence of alkaline and oxidative pre-treatment of waste corn cobs on biohydrogen generation efficiency via dark fermentation
PublicationStages of waste corn cobs processing leading to the production of biohydrogen via dark fermentation are presented and discussed in this paper. Firstly, the effects of pretreatment conditions i.e. alkaline, alkaline-oxidizing and Fenton oxidizing pre-treatment of lignocellulosic biomass on the removal of lignin were examined. The solid residue obtained in the first stage was subjected to saccharification by means of enzymatic hydrolysis....
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Local Mesh Deformation for accelerated parametric studies based on the Finite Element Method
PublicationThis paper presents an approach for enhancing the efficiency of two-dimensional Finite Element Method analysis in parametric studies or optimisation process of microwave components. The new approach involves local mesh deformation applied near the elements that are modified during computations. Since in the proposed approach the topology of the mesh remains unchanged, a new mesh does not have to be generated from scratch when the...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublicationThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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Modeling incipient creep damage effects on Barkhausen noise and magnetoacoustic emission.
PublicationZaproponowano model fizyczny opisujący zmiany natężenia efektu Barkhausena i emisji magnetoakustycznej podczas procesu degradacji stali ekploatowanych w przemyśle energetycznym.
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Shift-Msplit* Estimation in Deformation Analyses
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Stesses in tank shell with shape deformation
PublicationW referacie przedstawiono wyniki pomiarów naprężeń w płaszczy stalowego, rzeczywistego zbiornika. Pomiary przeprowadzono przy pomocy tensometrii elektrooporowej. Obiektem badań był stalowy zbiornik pionowy z dachem pływającym o pojemności nominalnej 12.000 m3. Defermacje płaszcza stalowego badanego obiektu wynoszą od -170 do +150 mm.
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Deformation Analysis of a Composite Bridge during Proof Loading Using Point Cloud Processing
PublicationRemote sensing in structural diagnostics has recently been gaining attention. These techniques allow the creation of three-dimensional projections of the measured objects, and are relatively easy to use. One of the most popular branches of remote sensing is terrestrial laser scanning. Laser scanners are fast and efficient, gathering up to one million points per second. However, the weakness of terrestrial laser scanning is the...
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The impact of footing conditions of a vertical-axis floating-roof tank on structural shell deformation
PublicationStructural shells of fuel tanks are often subjected to geometric imperfections which may lead to exceeding the ultimate and serviceability limit states. One of the means triggering shell deformation is non-uniform settlement caused by incoherent soil conditions. Analysis carried out in the work concerns of vertical-axis, floating-roof cylindrical shell which volume is 50.000 m3, founded on a complex multi-layered soil. The sensitivity...
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Deformation and Surface Color Changes of Beech and Oak Wood Lamellas Resulting from the Drying Process
PublicationThe drying process was examined relative to parameters’ influence on the deformation and surface layer color changes of beech wood (Fagus sylvatica L.) and oak wood (Quercus robur L.). The goal was to analyze the impact of drying process conditions, wood and growth rings types, and load on the deformation and surface color changes of drying thin wooden elements. A further aim was to reduce the time of the lamella drying and minimize...
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On topology optimization of large deformation contact-aided shape morphing compliant mechanisms
PublicationA topology optimization approach for designing large deformation contact-aided shape morphing compliant mechanisms is presented. Such mechanisms can be used in varying operating conditions. Design domains are described by regular hexagonal elements. Negative circular masks are employed to perform dual task, i.e., to decide material states of each element and also, to generate rigid contact surfaces. Each mask is characterized by...
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The study on the appearance of deformation defects in the yacht lamination process using an AI algorithm and expert knowledge
PublicationThis article describes the application of the A-priori algorithm for defining the rule-based relationships between individual defects caused during the lamination process, affecting the deformation defect of the yacht shell. The data from 542 yachts were collected and evaluated. For the proper development of the algorithm, a technological process of the yacht lamination supported by expert decisions was described. The laminating...
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Thermal stabilization and permanent deformation resistance of LWA/PCM-modified asphalt road surfaces
PublicationThis paper presents the results of attempts at reducing the problem of solar overheating of asphalt road pavement surfaces, resulting in weakening and accelerated destruction of the aforementioned structures. To protect pavement surfaces against periodic overheating, standard asphalt mixture AC 16 W 35/50, used for binder course, has been modified by replacing one of the aggregate fractions from the mineral mixture with lightweight...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublicationThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Pre-Treatment of Furniture Waste for Smokeless Charcoal Production
PublicationThe aim of this study was to assess the possibility of using furniture waste for smokeless fuel production using the pyrolysis process. Four types of wood-based wastes were used in the pyrolysis process: pine sawdust (PS), chipboard (CB), medium-density fiberboard (MDF), and oriented strand board (OSB). Additionally, the slow and fast types of pyrolysis were compared, where the heating rates were 15 C/min and 100 C/min, respectively....
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Revisiting the pre-hypertension debate: Increasing evidence for treatment – or not?
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Residue-Pole Methods for Variability Analysis of S-parameters of Microwave Devices with 3D FEM and Mesh Deformation
PublicationThis paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional Monte-Carlo...
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Attempt to modeling with FEM of the impact of initial oval shape of tube into creep process.
PublicationOpisano zasady modelowania metodą elementów skończonych zjawiska pełzania dla elementów typu rura oraz pokazano wynik próby modelowania za pomocą MES wpływu początkowej owalności rury na proces pełzania.
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Influence of Installation Effects on Pile Bearing Capacity in Cohesive Soils – Large Deformation Analysis Via Finite Element Method
PublicationIn this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs...
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A nonlinear approach to modelling gas bubble deformation.
PublicationPrzedstawiono model wyjaśniający wpływ deformacji pęcherzyka na występowanie zjawiska chaosu podczas generowania pęcherzyków gazowych z pojedynczej dyszy zanurzonej w cieczy.
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Modeling knee joint endoprosthesis mode of deformation
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Deformation of thin metal and composite sheets by using anti-buckling fixture for large deformation under tension–compression cyclic loading
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Effects of full displacement pile installation on the stress and deformation state of surrounding soil: review
PublicationSeveral field and model tests have been conducted to investigate the impact of pile installation on bearing capacity. However, little is known about how piles behave during installation, how they interact with the surrounding soil, and how this affects sandy soil properties. This review paper investigates the effect of pile driving on surrounding sandy soil as it compacts sandy soil near to the pile. For this purpose, various related...
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An Ontology-based Contextual Pre-filtering Technique for Recommender Systems
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Pre-arrangement of solvability, complexity, stability and quality of GPC systems
PublicationPraca dotyczy podstawowych problemów strojenia algorytmów dyskretnoczasowego uogólnienia sterowania predykcyjnego (GPC). Optymalne sterowanie predykcyjne, w sensie pewnego kwadratowego funkcjonału kosztów, wyznacza się rozwiązując odpowiednie liniowe zadanie. W pracy podano warunki, przy których macierz tego zadania jest macierzą o pełnym kolumnowym rzędzie - co gwarantuje istnienie optymalnego sterownika. W następnej kolejności...
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Municipal soild waste settlement (MSWS) model with account for integrated creep and degradation processes.
PublicationModel oparto na superpozycji składowych osiadania zależnych od obciązenia i wpływu czasu, zgodnie z obserwowanym zachowaniem się odpadów komunalnych w warunkach polowych i laboratoryjnych. Składowe osiadania zależne od obciązenia, które przyrastają w miarę dokładania kolejnych warstw odpadów, oblicza się z uwzględnieniem modułu podatności zależnego od poziomu obciążenia. Składowe osiadania wynikające z upływu czasu obejmują osiadanie...
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Complementary study with magnetic and acoustic techniques of A336 steel damage state due to creep
PublicationBadano możliwość detekcji w sposób nieniszczący zmian w mikrostrukturze stali A336 poddanej próbie pełzania. Testowano dwie magnetyczne techniki (klasyczny efekt Barkhausena i emisję magnetoakustyczną) oraz dwie nowe techniki ultradźwiękowe (pomiar współczynnika elasto-akustycznego oraz dwójłomność akustyczną). Wykazano, iż wyniki badań akustycznych są komplementarne do wyników badań magnetycznych.