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Search results for: DYNAMIC MECHANICAL ANALYSIS
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Experimental determination of dynamic properties of cylindrical steel tank model filled with liquid
PublicationIn technical branches, such as chemical or petroleum industries, cylindrical steel tanks are essential structures used for storage of liquid products. Any failure might have disastrous consequences, therefore their safety and reliability is essential. The aim of the present paper is to show the results of the experimental study which has been conducted on a scaled model of a real tank used in Poland. The investigation was carried...
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Processing, mechanical and thermal behavior assessments of polycaprolactone/agricultural wastes biocomposites
PublicationIn this paper, brewer’s spent grain (BSG) was applied as potential lignocellulose biofiller in biocompos-ites based on polycaprolactone (PCL). The PCL/BSG biocomposites filled with varying content of biofillerswere prepared via low-temperature melt-compounding. These conditions allow limiting thermal degra-dation of used biofillers during processing. The influence of biofiller content (ranging from 25 to 200parts by weight on 100...
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Corrosion degradation impact on mechanical properties of structural steel
PublicationRecently, extensive research was conducted regarding the impact of corrosion degradation on the mechanical properties of structural steel. Studies show that at the material level, the microstructure is somewhat unchanged due to corrosion degradation. However, the corrosion causes pits and structural surface irregularities that consequently impact the mean stress-strain response of typical coupon specimens subjected to tensile loading....
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Fractional Order Dynamic Positioning Controller
PublicationImproving the performance of Dynamic Positioning System in such applications as station keeping, position mooring and slow speed references tracking requires improving the position and heading control precision. These goals can be achieved through the improvement of the ship control system. Fractional-order calculus is a very useful tool which extends classical, integer-order calculus and is used in contemporary modeling and control...
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Special Issue "Applications of Finite Element Modeling for Mechanical and Mechatronic Systems"
PublicationNumerical modeling is very important in today's engineering because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim...
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Active Dynamic Thermography in Medical Diagnostics
PublicationThis is an overview of active thermal imaging methods in medical diagnostics using external thermal stimulation. In this chapter, several clinical cases diagnosed using the active dynamic thermography method, ADT, are presented. Features of this technology are discussed and main advantages underlined. Applications in skin burn diagnostics and quantitative evaluation leading to modern classification of burned patients for further...
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Performance of organic coatings upon cyclic mechanical load
PublicationA number of engineering structures fail due to the fatigue damage resulting from cyclic mechanical stress. However, as far as organic coatings are concerned this degradation factor remains underestimated. In the paper the authors propose a methodology combining global electrochemical impedance spectroscopy and local atomic force microscopy measurements for evaluation of coating resistance to an impact of repetitive mechanical stress. Typical...
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PROCESSING, MECHANICAL AND THERMAL PROPERTIES OF RECYCLED LOW-DENSITY POLYETHYLENE STREAMS
PublicationThe recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for the potential methods of their utilization. Nevertheless, for the efficient application of recycled materials it is crucial to analyze their performance. Therefore, in presented paper we investigated the processing (melt flow index),...
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...
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THE INFLUENCE OF PET MECHANICAL PROPERTIES ON SBM PROCESS PARAMETERS – LITERATURE REVIEW
PublicationIn the paper it is said about the influence of PET (polyethylene terephthalate) mechanical properties on SBM (stretch blow molding) process output parameters changes. The below paper mentions also about the influence of PET orientation and crystallization processes on mechanical and thermal properties of PET material during SBM process. All mechanical data of PET material and SBM process output parameters changes are from collected...
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Structure, morphology and mechanical behaviour of novel bio-based polyurethane composites with microcrystalline cellulose
PublicationThe aim of this work was to obtain bio-based polyurethane composites using biocomponents such as, bio-glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The prepolymer method was used to prepare the bio-based polyurethane matrix. Prepolymer synthesised from 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% wt. commercial polyether and 25% wt. hydroxylated soybean oils (H3)...
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Mechanical Properties of Bio-Composites Based on Epoxy Resin and Nanocellulose Fibres
PublicationThe aim of our research was to investigate the effect of a small nanocellulose (NC) addition on an improvement of the mechanical properties of epoxy composites. A procedure of chemical extraction from pressed lignin was used to obtain nanocellulose fibers. The presence of nanoparticles in the cellulose pulp was confirmed by FTIR/ATR spectra as well as measurement of nanocellulose particle size using a Zetasizer analyzer. Epoxy...
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Fading Characteristics for Dynamic Body-to-Body Channels in Indoor and Outdoor Environments
PublicationThis paper presents an analysis of the fading characteristics in dynamic body-to-body channels, based on measurements performed at 2.45 GHz in indoor and outdoor environments. The statistical analysis of the small- and large-scale fading shows that the Nakagami Distribution is the best model for the former and the Log-Normal one for the latter. An important influence of body shadowing...
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The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete
PublicationThe authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures. The analysis included the assessment of changes in dierences in endurance parameters over various...
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Optimal Rotating Receiver Angles Estimation for Multicoil Dynamic Wireless Power Transfer
PublicationThis study proposed an approach to dynamic wireless charging that uses a rotating receiver coil. Our simulation study focused on the verification of a novel way of increasing the coupling coefficient and power transfer stability by following the flux of the transmitting coils. To obtain the highest possible coupling by means of the FEM analysis, we studied the optimization of the trajectory of the angular velocity of the rotating...
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The influence of PET mechanical properties on Stretch Blow Molding (SBM) process
PublicationIn the paper it is said about the influence of PET mechanical properties on SBM process parameters changes. The below paper mentions also about the influence of PET orientation and crystallization processes which have a very big influence on mechanical and thermal properties of PET material during SBM process. All mechanical data of PET material and SBM process parameters change in time are been got from collected literature which...
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Mechanical Recycling via Regrinding, Rebonding, Adhesive Pressing, and Molding
PublicationIncreasing amount of polyurethane foams waste (e.g. from the building or furniture industry) produced every year resulted in the intensive development of their recycling methods. This chapter covers most important mechanical recycling methods, i.e. regrinding, rebonding, adhesive pressing, and molding. The procedure, required equipment and chemicals (if needed) for each method were described. The possible applications of the products...
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Adaptive dynamic control allocation for over-actuated dynamic positioning system based on backstepping method in case of thruster faults
PublicationThe objective of the research considered in this paper is dynamic positioning of a nonlinear over-actuated marine vessel in the presence of limited information about thruster forces. First, the adaptive backstepping method is used to estimate the input matrix which will compensate partial loss of actuator effectiveness in the presence of actuator dynamics. Then, the adaptive commanded virtual forces and moment are allocated into...
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Numerical Evaluation of Dynamic Response of a Steel Structure Model under Various Seismic Excitations
PublicationThe present paper reports the results of the study, which was designed to perform a numerical evaluation of dynamic response of a single-storey steel structure model. The experimental model was previously subjected to a number of different earthquake ground motions during an extensive shaking table investigation. The analyzed structure model was considered as a 1-DOF system with lumped parameters, which were determined by conducting...
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Application of galvanodynamic impedance spectroscopy for studying passive film cracking under mechanical strain
PublicationThe paper reports the results of simultaneous mechanical and electrochemical investigations on austenitic (18/8) stainless steel in a 2 % solution of sulphuric acid. The measurements were performed using Galvanodynamic Electrochemical Impedance Spectroscopy (GDEIS). Electrochemical analysis of mechanical passive layer cracking and repassivation conditions during a tensile test was carried out. Application of this methodology allowed...
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Experimental study on static and dynamic properties of polymer mass
PublicationA new method of repairing damaged structures by filling the cracks with a specially prepared polymer mass has been recently proposed. This new and innovative technique, known as the Flexible Joint Method (FJM), is mainly dedicated to masonries and 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...
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Dynamic Positioning Capability Assessment for Ship Design Purposes
PublicationThe article focuses on solving a problem of optimal thrust distribution over the actuators in a ship Dynamic Positioning, according to DNV-ST-0111 standard, Level 1. The classic Quadratic Programming approach is combined with the numerical solusion used to handle the propeller with the rudder constraints in the optimization task and the influence between thrusters and skeg. It is presented as an efficient method of minimizing the...
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Mechanical-Level Hardware-In-The-Loop and Simulation in Validation Testing of Prototype Tower Crane Drives
PublicationIn this paper, the static and dynamic simulations, and mechanical-level Hardware-In-the-Loop (MHIL) laboratory testing methodology of prototype drive systems with energy-saving permanent-magnet electric motors, intended for use in modern construction cranes is proposed and described. This research was aimed at designing and constructing a new type of tower crane by Krupiński Cranes Company. The described research stage was necessary...
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Modeling of wood frame structures with different insulation materials under damaging dynamic loading
PublicationWood frame buildings are very popular in regions that are exposed to different dynamic excitations, such as damaging earthquakes. Their seismic resistance is really important in order to prevent structural damages and human losses. This paper presents the results of advanced numerical investigation carried out using the FEM. Based on the models of wall panels, the numerical model of real structure of the wood frame building has...
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Dynamic unattended measurement based routing algorithm for diffServ architecture
PublicationDynamic routing is very important in terms of assuring QoS in today's packet networks especially for streaming and elastic services. Existing solutions dedicated to dynamic routing are often too complicated and seem to be not usable in real time traffic scenarios where transferred traffic may vary significantly. This was the main reason for research and new routing mechanism proposal which should apply to today's packet networks....
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Economic benefits of dynamic charging of electric buses
PublicationDiesel engines buses are still the most used type of buses. Electric buses provide promising green alternatives and a lot of advantages, but their main disadvantages are limited travel range and long charging time. This article is a presentation of innovative solution for charging of electric busses - Dynamic Charging (IMC). The modern IMC system in Solingen was presented. At the end of the article, a proposal was made to introduce...
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Dynamic Positioning System with Vectorial Backstepping Controller
PublicationThe problem of synthesis a dynamic positioning system for low frequency model of surface vessel was considered in this paper. The recursive vectorial backstepping control design was used to keep a fixed position and heading in presence of wave disturbances. The passive observer was introduced to smooth the measurements and to estimate the velocities needed for the control algorithm. Some parameters of observer were optimized off-line...
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Effects of mechanical stress on electrical arameters and noise of supercapacitors
PublicationResults of noise and electrical parameters measurements of prototype electrochemical double layer capacitors (EDLC) are reported at the presence of selected mechanical stress. This issue is of great importance due to future applications in wearable technology. The measurement results are compared, and we may conclude than flicker noise is more sensitive to any stress than other considered electrical parameters.
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Adaptive filtering approach to dynamic weighing: a checkweigher case study
PublicationDynamic weighing, i.e., weighing of objects in motion, with out stopping them on the weighing platform, allows one to increase the rate of operation of automatic weighing systems used in industrial production processes without compromising their accuracy. The paper extends and compares two approaches to dynamic weighing, based on system identification and variable-bandwidth filtering, respectively. Experiments, carried on a conveyor...
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Ship Dynamic Positioning Based on Nonlinear Model Predictive Control
PublicationThe presented work explores the simulation test results of using nonlinear model predictive control algorithm for ship dynamic positioning. In the optimization task, a goal function with a penalty was proposed with a variable prediction step. The results of the proposed control algorithm were compared with backstepping and PID. The effect of estimation accuracy on the control quality with the implemented algorithms was investigated....
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Processing, Mechanical and Morphological Properties of GTR Modified by SBS Copolymers
PublicationIn this work, ground tire rubber (GTR) was thermo-mechanically treated in the presence of styrene-butadiene-styrene (SBS) copolymers. During preliminary investigation, the effects of different SBS copolymer grades, the variable content of SBS copolymer on the Mooney viscosity, and the thermal and mechanical properties of modified GTR were determined. Subsequently, GTR modified by SBS copolymer and cross-linking agents (sulfur-based...
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Dynamic modeling of non-cylindrical curved viscoelastic single-walled carbon nanotubes based on the second gradient theory
PublicationThis paper is devoted to the theoretical study of the dynamic response of non-cylindrical curved viscoelastic single-walled carbon nanotubes (SWCNTs). The curved nanotubes are largely used in many engineering applications, but it is challenging in understanding mechanically the dynamic response of these curved SWCNTs when considering the influences of the material viscosity. The viscoelastic damping effect on the dynamic response...
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Mechanical behaviour of knit synthetic mesh used in hernia surgery
PublicationPurpose: There is a discussion in literature concerning mechanical properties and modelling of surgical meshes. An important feature of elastic modulus dependency on load history is taken into account in this paper, as implants are subjected to variable loading during human activity. The example of DynaMesh®-IPOM surgical implant is studied. Methods: The analysis is based on failure tension tests and cyclic loading and unloading...
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Krótko- i długookresowe skorygowane krańcowe skłonności do konsumpcji. Gospodarka Polski w latach 1995-2018
PublicationWe wstępnej części artykułu - odwołując się do teorii Keynesa - omówiono i zdefiniowano podstawowe relacje makroekonomiczne pomiędzy konsumpcją globalną a produktem krajowym brutto. W następnej kolejności przeprowadzono analizę informacji statystycznych dotyczących prywatnych wydatków konsumpcyjnych gospodarstw domowych (C) oraz globalnych wydatków konsumpcyjnych społeczeństwa (CO) na tle produktu krajowego brutto (PKB) w Polsce...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublicationThe 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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Identification of dynamic parameters in the context of diagnostics of steel tank with different level of liquid.
PublicationThe paper presents an experimental study to identify the dynamic parameters of a water-filled tank model. The experimental modal analysis approach involving the excitation at one point of the structure and acquisition of vibra tions at selected points distri buted over the tank surface allowed to determine the resonance frequencies, mode shapes and damping ratios. The main aim of the research was to examine the influence of...
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Concurrent Video Denoising and Deblurring for Dynamic Scenes
PublicationDynamic scene video deblurring is a challenging task due to the spatially variant blur inflicted by independently moving objects and camera shakes. Recent deep learning works bypass the ill-posedness of explicitly deriving the blur kernel by learning pixel-to-pixel mappings, which is commonly enhanced by larger region awareness. This is a difficult yet simplified scenario because noise is neglected when it is omnipresent in a wide...
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Mechanical properties of polyvinyl chloride-coated fabric under cyclic tests
PublicationThe aim of the present paper is to propose a method of laboratory tests necessary for the identification of mechanical properties of the coated fabric. The material parameters of the coated fabric AF 9032 are specified on the basis of the uniaxial and biaxial tensile tests. For the identification process, the techniques based on the least squares methods are used. Additionally, the uniaxial and biaxial cyclic tests are performed...
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Biological and mechanical research of titanium implants covered with bactericidal coating
PublicationThe paper concerns the biological and mechanical properties of titanium implants with an antibacterial coating. The Ti13Zr13Nb alloy samples were coated with hydroxyapatite (HAp) coatings using the electrophoretic deposition technique (EPD). Subsequently, the surface of the samples was modified with silver, copper, and nickel nanoparticles by the immersion method. Different titanium sample types (i.e. HAp-only and nanometals-enriched...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublicationThe paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described...
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Aerodynamic Shape Optimization for Delaying Dynamic Stall of Airfoils by Regression Kriging
PublicationThe phenomenon of dynamic stall produce adverse aerodynamic loading which can adversely affect the structural strength and life of aerodynamic systems. Aerodynamic shape optimization (ASO) provides an effective approach for delaying and mitigating dynamic stall characteristics without the addition of auxiliary system. ASO, however, requires multiple evaluations time-consuming computational fluid dynamics models. Metamodel-based...
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Dynamic Compatibility Matching of Services for Distributed Workflow Execution
PublicationThe paper presents a concept and an implementation of dynamic learn-ing of compatibilities of services used in a workflow application. While services may have the same functionality, they may accept input and produce output in different formats. The proposed solution learns matching of outputs and inputs at runtime and uses this knowledge in subsequent runs of workflow applications. The presented solution was implemented in an...
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An Evaluation Engine for Dynamic Ranking of Cloud Providers
PublicationThe paper focuses on creation of an effective dynamic ranking service for IaaS, PaaS and SaaS cloud providers. It considers building a quality model for this purpose along with definition of quality measure- ment procedures. The paper discusses several techniques known from already existing price comparison engines that could be modified and adopted for comparison of cloud providers. A technique for filtering measured data is proposed,...
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An investigation on the role of GMA grafting degree on the efficiency of PET/PP-g-GMA reactive blending: morphology and mechanical properties
PublicationGlycidyl methacrylate (GMA) has been grafted on polypropylene (PP) with the aid of styrene (St) comonomer, by changing dicumyl peroxide initiator content, GMA level, and St concentration. The performance of the resulting PP-g-GMA reactive material towards static and dynamic mechanical properties of poly (ethylene terephthalate) (PET) was monitored in terms of grafting reaction variables and compatibilizer content. Fourier transform...
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Sieć sensorowa do rejestracji drgań górnej sieci trakcyjnej w celach diagnostyki eksploatacyjnej
PublicationWraz ze wzrostem prędkości kolejowych pojazdów elektrycznych zwiększają się wymagania utrzymania sieci trakcyjnej w odpowiednim stanie technicznym. Ciągły monitoring i diagnostyka pozwalają wykrywać pogarszającą się jakość odbioru prądu z sieci jezdnej. Jedną z metod jest umieszczenie czujników przyspieszenia na przewodzie jezdnym. Analiza przebiegu przyspieszenia pozwala określić jakość współpracy sieci jezdnej z pantografem....
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Badania eksperymentalne i analiza numeryczna sklepień ceglanych. Wzmocnienie sklepień z wykorzystaniem struktur tensegrity.
PublicationCelem pracy jest opracowanie wzmocnienia zabytkowych sklepień murowych prętowo-cięgnowymi strukturami tensegrity. W tym celu przeanalizowano zagadnienia uszkodzeń, analizy oraz wzmacniania kopuł i sklepień murowych. W kolejnej części rozprawy przedstawiono prace badawczo-rozwojowe zakończone skutecznym wdrożeniem typoszeregu hal namiotowych o konstrukcji prętowo-cięgnowej typu tensegrity. Przeprowadzono badania dynamiczne oraz...
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Mechanical and structural investigations of wings of selected insect species
PublicationThis paper presents research and measurements leading to obtaining the Young’s modulus of wing bearing structures of selected insect species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus...
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Active Dynamic Infrared Thermal Imaging in Burn Depth Evaluation
PublicationThe aim of this study was to find the relationship between active dynamic thermography (ADT) with cold excitation and burn depth. This new modality of evaluation of burns seems to be an attractive proposal for quantitative classification, allowing proper choice of burn wound treatment: conservative or surgical, especially compared with static thermography. The work was an in vivo experiment on domestic pigs, and a small number...
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Dynamic Bankruptcy Prediction Models for European Enterprises
PublicationThis manuscript is devoted to the issue of forecasting corporate bankruptcy. Determining a firm’s bankruptcy risk is one of the most interesting topics for investors and decision-makers. The aim of the paper is to develop and to evaluate dynamic bankruptcy prediction models for European enterprises. To conduct this objective, four forecasting models are developed with the use of four different methods—fuzzy sets, recurrent and...
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On Nonlinear Dynamic Theory of Thin Plates with Surface Stresses
PublicationWe discuss the modelling of dynamics of thin plates considering surface stresses according to Gurtin–Murdoch surface elasticity. Taking into account the surface mass density we derive the two-dimensional (2D) equations of motion. For the reduction of the three-dimensional (3D) motion equations to the 2D ones we use the trough-the-thickness integration procedure. As a result, the 2D dynamic parameters of the plate depend not only...