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Wyniki wyszukiwania dla: NON-LINEAR MUSKINGUM EQUATION
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Interannual Variability of the GNSS Precipitable Water Vapor in the Global Tropics
PublikacjaThis paper addresses the subject of inter-annual variability of the tropical precipitable water vapor (PWV) derived from 18 years of global navigation satellite system (GNSS) observations. Non-linear trends of retrieved GNSS PWV were investigated using the singular spectrum analysis (SSA) along with various climate indices. For most of the analyzed stations (~49%) the GNSS PWV anomaly was related to the El Niño Southern Oscillation...
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublikacjaThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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Predicting Value of Binding Constants of Organic Ligands to Beta-Cyclodextrin: Application of MARSplines and Descriptors Encoded in SMILES String
PublikacjaThe quantitative structure–activity relationship (QSPR) model was formulated to quantify values of the binding constant (lnK) of a series of ligands to beta–cyclodextrin (β-CD). For this purpose, the multivariate adaptive regression splines (MARSplines) methodology was adopted with molecular descriptors derived from the simplified molecular input line entry specification (SMILES) strings. This approach allows discovery of regression...
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Elastic scattering of electrons by water: An ab initio study
PublikacjaIn this work we devise a theoretical and computational method to compute the elastic scattering of electrons from a non-spherical potential, such as in the case of molecules and molecular aggregates. Its main feature is represented by the ability of calculating accurate wave functions for continuum states of polycentric systems via the solution of the Lippmann-Schwinger equation, including both the correlation effects and multi-scattering...
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Cleaner energy for sustainable future using hybrid photovoltaics-thermoelectric generators system under non-static conditions using machine learning based control technique
PublikacjaIn addition to the load demand, the temperature difference between the hot and cold sides of the thermoelectric generator (TEG) module determines the output power for thermoelectric generator systems. Maximum power point tracking (MPPT) control is needed to track the optimal global power point as operating conditions change. The growing use of electricity and the decline in the use of fossil fuels have sparked interest in photovoltaic-TEG...
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Proportional-Derivative and Model-Based Controllers for Control of a Variable Mass Manipulator
PublikacjaIn the paper, numerical analysis of dynamics of a variable mass manipulator is presented. A revolute joints composed manipulator is considered. Payload of the gripper is considered as the only element characterized by unknown value of its mass (variable between subsequent operations). As in other cases of the revolute joints composed manipulators, its behaviour dependents significantly on the pose of the manipulator. When the manipulator...
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Impacts in case of triple unilaterally constrained system
PublikacjaThe this paper focus on the behaviour of a “rigid” body biting into another “rigid” body, with some nonzero relative velocity. In the presently considered case, the introduced collision appears between a selected element of a multibody structure and its reference body being interpreted as the motionless ground. Instead of the classic case, described in a number of dissertations, where a single impacting contact is considered, three...
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Tensile failure study of 3D printed PLA using DIC technique and FEM analysis
PublikacjaThe paper presents the experimental and numerical study of the failure behaviour of Fused Filament Fabricated (FFF) Polylactic Acid (PLA) samples subjected to tensile load. The examined samples are printed in flat orientation with 0◦, 45◦ and 90◦ raster angles. During the experiments the deformation of the specimens is continuously scanned with the 3D Aramis measuring system utilizing the digital imaging correlation technique,...
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SHORT REVIEW AND 3-D FEM ANALYSIS OF BASIC TYPES OF FOUNDATION FOR OFFSHORE WIND TURBINES
PublikacjaSome problems of the foundations of offshore wind turbines are considered in this paper. A short review is presented on the two basic types of foundations, i.e. monopiles and gravity foundations, including their basic features and applications as well as general design considerations. Also, some issues regarding analysis are discussed, including geotechnical problems and modelling techniques. A numerical model of offshores turbine...
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Performance Evaluation of GAM in Off-Body Path Loss Modelling for Body Area Networks
PublikacjaThis paper addresses the performance evaluation of an off-body path loss model, based on measurements at 2.45 GHz, which has been developed with the use of the Generalised Additive Model, allowing to model a non-linear dependence on different predictor variables. The model formulates path loss as a function of distance, antennas’ heights, antenna orientation angle and polarisation, results showing that performance is very sensitive...
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A model of the response of the MGS-6 gravity sensor to tilting
PublikacjaThe reliable interpretation of the measurements made by the Micro-g marine gravimetric system (MGS-6) depends on how the temporary changes of the scale coefficients such as gravimeter scale factor, vertical cross-coupling (VCC) effect, tiltmeter cross and tiltmeter long are compensated for during the signal analysis. The listed coefficients cannot be determined from readings during the measurements or by analysing the final data....
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On the Matano Plane Position in Multicomponent Diffusion Couples
PublikacjaEven though several methods of diffusion analysis avoid a necessity for the Matano plane determination, the Matano plane locations are of interest in the multicomponent couples and when tracer experiments are performed. The positions of the Matano plane calculated from the concentration profiles should be exactly the same. However, due to experimental errors, the results can differ significantly. In the paper we consider Matano...
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On the Matano Plane Position in Multicomponent Diffusion Couples
PublikacjaEven though several methods of diffusion analysis avoid a necessity for the Matano plane determination, the Matano plane locations are of interest in the multicomponent couples and when tracer experiments are performed. The positions of the Matano plane calculated from the concentration profiles should be exactly the same. However, due to experimental errors, the results can differ significantly. In the paper we consider Matano...
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Buckling Analysis of Cold Formed Silo Column
PublikacjaThe paper is devoted to stability analysis of different models of steel cold formed silo column. The steel cylindrical silos are often composed of corrugated walls and vertical open-sectional columns uniformly placed along the silo circumference. Both the whole 3D silo, a simplified model consisting of one column with a part of the silo walls, and a single column resting on elastic foundation provided by the silo walls were analyzed....
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An experimental study on polymer mass
PublikacjaA new method of repairing damaged structures by filling the cracks with specially prepared polymer mass has been recently proposed. The technique is mainly dedicated to historical objects where minimum intervention is permitted. The flexible joint bonds the disrupted elements and ensures further safe exploitation of a damaged structure. The aim of the present paper is to show the results of an experimental study on polymer mass...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublikacjaThe paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure...
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Method of selecting the LS-SVM algorithm parameters in gas detection process
PublikacjaIn this paper we showed the method of resistive gas sensors data processing. The UV irradiation and temperature modulation was applied to improve gas sensors’ selectivity and sensitivity. Noise voltage across the sensor’s terminals (proportional to its resistance fluctuations) was recorded to estimate power spectral density. This function was an input data vector for LS-SVM (least squares – support vector machine) algorithm, which...
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Numerical assessment of ultimate strength of severe corroded stiffened plates
PublikacjaThe objective of this work is to investigate numerically (using the non-linear FEM and the approach stipulated by the Common Structural Rules) the severe nonuniform corrosion degradation effect on the ultimate strength of stiffened plates and compare the results to the already published experimental works. Different factors governing structural behavior of corroded stiffened plates are investigated, such as corrosion degradation level,...
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Footbridges. Dynamic Design – Selected Problems
PublikacjaModern footbridges create challenge in esthetic and structural design. Breaking the proven canons is a recipe for architectural success. However esthetic form has to be also a functional pedestrian bridge. Therefore a good FEM modeling is a key element in engineering part of design. The paper presents selected problems related to the modeling of the dynamic construction of footbridges. Several basic dynamic problems concerning...
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Understanding the capacitance of thin composite films based on conducting polymer and carbon nanostructures in aqueous electrolytes
PublikacjaIn this work electrochemical performance of thin composite films consisted of poly(3,4-ethylenedioxythiophene) (PEDOT), graphene oxide (GOx) and oxidized multiwalled carbon nanotubes (oxMWCNTs) is investigated in various sulphates (Li2SO4, Na2SO4, K2SO4, MgSO4) and acidic (H2SO4) electrolytes. Capacitance values, rate capability and cycling stability achieved for the composite layers are correlated with the electrolytes’ properties...
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A System for Heart Sounds Classification
PublikacjaThe future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases – one of the major causes of death around the globe – a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However,...
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Interfacially modified LDPE/GTR composites with non-polar elastomers: From microstructure to macro-behavior
PublikacjaThis paper provides some new insights into the mechanism of interaction and modifications in thermoplastic composites based on low density polyethylene (LDPE), ground tire rubber (GTR) and non-polar elastomer. The composites were prepared using a co-rotating twin-screw extruder at variable LDPE/GTR ratio and constant elastomer content. Two types of commercial elastomer were applied: styrene-butadiene-styrene (SBS) block copolymers (Kraton®)...
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Sensitive Demonstration of the Twin-Core Couplers including Kerr Law Non-Linearity via Beta Derivative Evolution
PublikacjaTo obtain new solitary wave solutions for non-linear directional couplers using optical meta-materials, a new extended direct algebraic technique (EDAT) is used. This model investigates solitary wave propagation inside a fiber. As a result, twin couplers are the subject of this study. Kerr law is the sort of non-linearity addressed there. Because it offers solutions to problems with large tails or infinite fluctuations, the resulting...
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Thermodynamic Characteristics of Phenacetin in Solid State and Saturated Solutions in Several Neat and Binary Solvents
PublikacjaThe thermodynamic properties of phenacetin in solid state and in saturated conditions in neat and binary solvents were characterized based on differential scanning calorimetry and spectroscopic solubility measurements. The temperature-related heat capacity values measured for both the solid and melt states were provided and used for precise determination of the values for ideal solubility, fusion thermodynamic functions, and...
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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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Self-compacting grout to produce two-stage concrete
PublikacjaTraditional concrete (TC) is primarily composed of a mixture of cement, fine and coarse aggregates, and water. TC is made by mixing together all the components before placing them. Using non-traditional concrete (two-stage concrete) to solve and to eliminate the problem of the aggregate segregation which appears in TC and in the self-compacting concrete. Two-stage concrete (TSC) consists of two main components, namely the grout...
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Numerical Analysis of an Impact of Planned Location of Sewage Discharge on Natura 2000 Areas – The Dead Vistula Region Case Study
PublikacjaThis article presents results of an analysis of impact of a designed discharge of contaminated water into the Dead Vistula (Wisła Martwa) in the region of the Isthmus (Przesmyk) with the aim of determination of a possible effect of the pollution onto protected areas of Natura 2000 (bird habitats and sites, especially the Bird Paradise – Ptasi Raj) nature reserve. The analysis was conducted on the basis of the two-dimensional modelling...
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Mixed integer nonlinear optimization of biological processes in wastewater sequencing batch reactor
PublikacjaWastewater treatment plays a key role for humanity. The waste entering lakes, rivers, and seas deteriorates daily quality of life. Therefore, it is very important to improve the efficiency of wastewater treatment. From a control point of view, a biological wastewater treatment plant is a complex, non-linear, multidimensional, hybrid control system. The paper presents the design of the optimizing hierarchical control system applied...
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Electrochemistry from first-principles in the grand canonical ensemble
PublikacjaProgress in electrochemical technologies, such as automotive batteries, supercapacitors, and fuel cells, depends greatly on developing improved charged interfaces between electrodes and electrolytes. The rational development of such interfaces can benefit from the atomistic understanding of the materials involved by first-principles quantum mechanical simulations with Density Functional Theory (DFT). However, such simulations are...
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On-line assessment of oil quality during deep frying using an electronic nose and proton transfer reaction mass spectrometry
PublikacjaWe describe a novel method for the quality assessment of oil utilized for deep frying. The method is based on the analysis of frying fumes using a custom electronic nose. The quality score could be obtained after less than 3 min of analysis and without interrupting the frying process or sampling the oil directly. The obtained results were correlated with the peroxide value using a multivariate linear regression model. The most...
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Experimental and theoretical solubility advantage screening of bi-component solid curcumin formulations
PublikacjaA comprehensive experimental and theoretical screening was performed for identification of curcumin solubilizers. Experimental data led to formulation of a non-linear QSPR model correlating molecular descriptors with measured solubilities. The majority of synthesized binary systems exhibited a moderate enhancement of curcumin solubility, which was found to be the highest in the case of curcumin cocrystallized with pyrogallol. New...
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Synthesis and electrochemical characteristics of novel dithiocarbamate polymers
PublikacjaNovel dithiocarbamate compounds have been obtained by reacting a linear poly(ethylenimine)polymer, MW 50,000, with CS2. The resulting anionic polymers contain, depending on the reaction conditions, up to two sulfur atoms per one nitrogen atom (approx. 40% w/w). The polymers are soluble in dimethylsulfoxide and insoluble in acetonitrile solutions. In both solvents they are electrochemically active, in the latter case as a cast film...
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Wild oscillations in a nonlinear neuron model with resets: (I) Bursting, spike-adding and chaos
PublikacjaIn a series of two papers, we investigate the mechanisms by which complex oscillations are generated in a class of nonlinear dynamical systems with resets modeling the voltage and adaptation of neurons. This first paper presents mathematical analysis showing that the system can support bursts of any period as a function of model parameters, and that these are organized in a period-incrementing structure. In continuous dynamical...
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Structure-rheology relationship of fully bio-based linear polyester polyols for polyurethanes - Synthesis and investigation
PublikacjaThe synthesis of polyols from renewable substances as an alternative for petrochemical-based polyols play important matter in the polyurethane industry. In this work, the fully bio-based linear polyester polyols with different catalyst amounts were synthesized via two-step polycondensation method. The effect of various catalyst content on the structure and rheological behavior were established. Fourier Transform Infrared Spectroscopy,...
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A Selection of Starting Points for Iterative Position Estimation Algorithms Using Feedforward Neural Networks
PublikacjaThis article proposes the use of a feedforward neural network (FNN) to select the starting point for the first iteration in well-known iterative location estimation algorithms, with the research objective of finding the minimum size of a neural network that allows iterative position estimation algorithms to converge in an example positioning network. The selected algorithms for iterative position estimation, the structure of the...
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Detection of Closing Crack in Beam Based on Responses Induced by Harmonic Excitation
PublikacjaThe non-linear contact model was chosen to simulate the closed crack in the cantilever beam. The study examines the shape and characteristics of the phase diagram of a cantilever beam with closed cracks. It investigates how various crack properties influence the geometry of the phase diagram and proposes a method for identifying cracks based on their features. The area of each closed curve in the phase diagram is determined using...
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Determination of high-intensity sweeteners in beverages by high-performance liquid chromatography with mass spectrometry detection.
PublikacjaThe objective of the present study was to measure the concentration of nine high intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin dihydrochalcon, neotame, saccharin and sucralose) in different types of beverages available on the polish market. The proposed methodology reported here consists of a extraction with buffer composed of formic acid and N,N-diisopropylethylamine (pH 4.5) followed...
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Effective method for determining environmental loads on supporting structures for offshore wind turbines
PublikacjaThis paper presents a description of an effective method for determining loads due to waves and current acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was originally...
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Application of Multivariate Adaptive Regression Splines (MARSplines) Methodology for Screening of Dicarboxylic Acids Cocrystal Using 1D and 2D Molecular Descriptors
PublikacjaDicarboxylic acids (DiAs) are probably one of the most popular cocrystals formers. Due to the high hydrophilicity and non-toxicity, they are promising solubilizes of active pharmaceutical ingredients (APIs). Although DiAs appear to be highly capable of forming multicomponent crystals with various compounds, some systems reported in the literature are physical mixtures the solid state without forming stable intermolecular complex....
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Effective method for determining environmental loads on supporting structures for offshore wind turbines
PublikacjaThis paper presents a description of an effective method for determining loads due to waves, current and wind acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was...
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SUICIDES FOR ECONOMIC REASONS AS A MEASURE OF THE STATE OF THE ECONOMY: THE CASE OF POLAND
PublikacjaSuicides are a phenomenon observed in many countries. The causes of a decision so drastic as far as consequences are concerned include i.a. economic reasons. The question arises whether the changing number of suicides reflects the state of the economy. The direct link between the state of the economy and suicides has not been sufficiently studied so far. The authors of this article attempted to identify the links between selected...
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Massively parallel linear-scaling Hartree–Fock exchange and hybrid exchange–correlation functionals with plane wave basis set accuracy
PublikacjaWe extend our linear-scaling approach for the calculation of Hartree–Fock exchange energy using localized in situ optimized orbitals [Dziedzic et al., J. Chem. Phys. 139, 214103 (2013)] to leverage massive parallelism. Our approach has been implemented in the ONETEP (Order-N Electronic Total Energy Package) density functional theory framework, which employs a basis of non-orthogonal generalized Wannier functions (NGWFs) to achieve...
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On a flexomagnetic behavior of composite structures
PublikacjaThe popularity of the studies is getting further on the flexomagnetic (FM) response of nano-electro-magneto machines. In spite of this, there are a few incompatibilities with the available FM model. This study indicates that the accessible FM model is inappropriate when considering the converse magnetization effect that demonstrates the necessity and importance of deriving a new FM relation. Additionally, the literature has neglected...
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Thermal boundary conditions to simulate friction layers and coatings at sliding contacts
PublikacjaA brief review of the thermal boundary conditions specified at sliding interfaces was performed. New thermal boundary conditions were derived aimed at solving problems of sliding with account of surface layers representing friction layers and tribological coatings. Based on the assumption of linear temperature distributions in the surface layers, the proposed conditions enable one to simplify simulations by eliminating the surface...
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Damaged plasticity model - seismic analysis of structure of the Petronas Twin Towers (Kuala Lumpur) in Malaysia
PublikacjaThe article presents numerical simulations for the modelling of seismic impact on the structure of Petronas Twin Towers (Kuala Lumpur) in Malaysia with application of two methods. The Response Spectrum method, in which a spectrum of the structure's responses to an earthquake's impact is generated and the Acceletogram (BETA) method, in which we generate dynamic load in the form of a diagram of the connection between acceleration...
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Application of the Optimization Methods to the Search of Marine Propulsion Shafting Global Equilibrium in Running Condition
PublikacjaFull film hydrodynamic lubrication of marine propulsion shafting journal bearings in running condition is discussed. Considerable computational difficulties in non-linear determining the quasi-static equilibrium of the shafting are highlighted. The approach using two optimization methods (the particle swarm method and the interior point method) in combination with the specially developed relaxation technique is proposed to overcome...
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Experimental determination of basic mechanical properties of elastomeric polymer
PublikacjaThere are a lot of different methods of repairing and reinforcing damaged structures, but when it comes to historical buildings and other cultural heritage objects, it is as much about mechanical safety as the aesthetical aspects. Recently, a new and innovative method of repairing damaged structures by filling the cracks with a specially prepared polymer mass has been proposed. This new and innovative technique, known as the Flexible...
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High temperature proton conduction in LaSbO4
PublikacjaLanthanum orthoantimonate was synthesized using a solid‐state synthesis method. To enhance the possible protonic conductivity, samples with the addition of 1 mol% Ca in La‐site, were also prepared. The structure was studied by the means of X‐ray diffraction, which showed that both specimens were single phase. The materials crystallized in the space group P2 1 /n. Dilatometry revealed that material expands non‐linearly with the...
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Strain-dependent behaviour of cold recycled material mixtures in cyclic compression tests
PublikacjaThe purpose of the study is to evaluate strain-dependent behaviour of Cold Recycled Material (CRM) mixtures using three frameworks typically applied for Hot Mix Asphalt (HMA): linear viscoelastic (LVE) limits; non-linearity directions; changes in rheological model parameters. To this aim, the complex modulus of three CRM mixtures with different bitumen-to-cement ratio (0.2, 0.6 and 1.8) was measured in cyclic compression mode,...
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Chosen aspects of muscle biomechanics
PublikacjaConsidering a striated skeletal muscle as a different properties mechanical system, one can understand series of important phenomena happening in a real muscle phenomenon of muscle: 1) force delivery to skeletal apparatus through tendons; 2) changing of exerted muscle belly mass distribution with regards to skeletal apparatus; 3) beginning drop of muscle force. A disregard of first phenomenon causes an impossibility to explain...