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Search results for: kem
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A New Technique of Spine Disease Treatment Supported by ADRSK1 Device
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Numerical analysis of crack propagation in silicone nitride
PublicationThe properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation...
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Lean Six Sigma in French and Polish Small and Medium-Sized Enterprises - The Pilot Research Results
PublicationThe article presents results of the research conducted in Polish and French small and medium-sized enterprises referring to the context of the implementation and application of the concept of Lean Six Sigma. The research was conducted in the form of case studies, observations and individual interviews. The pilot studies led to the identification of the needs, expectations, concerns and experiences of these companies. At the same...
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Structure and Interactions in Chitosan Composites
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Fabrication and Study of BiNbO4 Ceramics
PublicationAim of the present research was to fabricate and study crystalline structure as well as dielectric properties of BiNbO4 ceramics. In the present study BiNbO4 ceramics was fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, and Nb2O5. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements proved conservation of the chemical...
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Damage-Involved Structural Pounding in Bridges under Seismic Excitation
PublicationDuring severe earthquakes, pounding between adjacent superstructure segments of highway elevated bridges was often observed. It is usually caused by the seismic wave propagation effect and may lead to significant damage. The aim of the present paper is to show the results of the numerical analysis focused on damage-involved pounding between neighbouring decks of an elevated bridge under seismic excitation. The analysis was carried...
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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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Detection of delamination in multi layer composite beams.
PublicationW pracy przedstawiono model belki kompozytowej z delaminacją. Omówiono czynniki propagacji fali sprężystej w belce i możliwości wykorzystania zmian w propagującej fali wywołanych delaminacją do jej detekcji.
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Use of Neural Networks in Diagnostics of Rolling-Element Bearing of the Induction Motor
PublicationBearing defect is statistically the most frequent cause of an induction motor fault. The research described in the paper utilized the phenomenon of the current change in the induction motor with bearing defect. Methods based on the analysis of the supplying current are particularly useful when it is impossible to install diagnostic devices directly on the motor. The presented method of rolling-element bearing diagnostics used indirect...
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Numerical Comparison of Damping Amplification Effects Obtained in Neighborhood of a Mechanism Singular Position - Viscous and Electromagnetic Cases
PublicationIn the paper, results of numerical investigations are presented. A continuous beam is considered as the main vibrating element. Two energy dissipations methods are compared: viscous dampers and DC generators. To increase the damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element, and the mechanism configuration is set as closed to the singular position...
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Selected Problems of Cogeneration Energy Systems Designing, Fueled with Landfill Biogas
PublicationThe article discusses the impact of the quality of biogas fuel for operation of generating sets with internal combustion engines. There are presented selected investigation results of landfill biogas fueled gensets operation. The article includes also discussion of the possibility of increasing the efficiency of biogas fuelled cogeneration systems. It also presents guidelines for the optimal design of landfill biogas fueled engines,...
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Hertzian Crack Propagation in Ceramic Rolling Elements
PublicationThe properties of ceramics are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such crack are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack...
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Mathematical Modelling of a Seismic Isolation System to Protect Structures During Damaging Earthquakes
PublicationThe present study aims to determine the effectiveness of a nonlinear mathematical model in simulating complex mechanical behaviour of a seismic isolation system to protect structures during strong and damaging earthquakes. In order to construct the Polymeric Bearings considered in this research, a specially prepared flexible polyurethane elastomer with increased damping properties has been used. The usefulness of the proposed mathematical...
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Investigation on Damage-Involved Structural Response of Colliding Steel Structures during Ground Motions
PublicationEarthquakes are the most unpredictable damaging loads which can affect civil engineering structures. Due to insufficient separation distance between adjacent structures with different dynamic properties, structural collisions may occur during ground motions. Although the research on structural pounding has recently been much advanced, the studies have mainly been conducted for concrete structures. The aim of this paper is to show...
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The Effectiveness of Polymer Damper in Damage Reduction of Temporary Steel Grandstand
PublicationA large number of accidents involving damage of temporary grandstands during different types of events were observed in the past. The aim of the paper is to analyse numerically the effectiveness of a polymer damper in damage reduction of a temporary steel scaffolding grandstand exposed to dynamic load due to jumping. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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Bearing Capacity of aluminum bars with built-up cross section and glued or welded connections
PublicationThe paper is focused on numerical analysis and experimental test of aluminum bars with glued and welded connections between separate members. The connection properties were tested experimentally. The numerical analysis were conducted for the beam and shell model of the structure. The shape and magnitude of initial geometric imperfection was taken into account
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Pounding between Inelastic Three-Storey Buildings under Seismic Excitations
PublicationStructural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations....
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Experimental Study on Pounding between Structures during Damaging Earthquakes
PublicationMutual pounding between structures during earthquakes may cause serious structural damage. The aim of this paper is to show the results of a shaking table experimental study focused on pounding between structures in series under several earthquake excitations. The experiments were performed using three tower models with different configurations and different gap distances between them. In the first stage of the study, one rigid...
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Enhancing the Seismic Resistance of Columns by GFRP Confinement Using Flexible Adhesive-Experimental Study
PublicationIn this paper, the results of two experiments, focused on testing the effectiveness of a method of enhancing the seismic (dynamic) resistance of masonry columns with the use of flexible polymer adhesive, are shown. The first experiment was devoted to investigate the damping properties of a polymer working between two stiff layers, whereas the aim of the second one was to verify if the identified damping properties of the polymer...
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Polymeric Bearings – A New Base Isolation System to Reduce Structural Damage during Earthquakes
PublicationBase isolators, like lead rubber bearings, high damping rubber bearings or friction pendulum systems are extensively used in practice in many seismically active regions to protect structures against earthquake forces. The present paper reports the results obtained from the experimental study aimed to determine the effectiveness of the Polymeric Bearings in suppressing structural vibrations during dynamic excitations and therefore...
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Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
PublicationThe safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical...
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High Speed Milling vibration surveillance with optimal spindle speed based on optimal speeds map
PublicationThe paper presents the method of the surveillance of the self-excited chatter vibration. At first, the workpiece modal parameters are estimated based on experimental data which leads to verification of computational model. Then, for selected surface points optimal spindle speeds are calculated. By considering sufficient amount of points it is possible to build a map of optimal spindle speeds. Experimental results show that this...
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Analysis of Rolling Resistance of Tires With Run Flat Insert
PublicationRun flat properties are required for tires intended for special applications like military or rescue vehicles. Run-Flat inserts make possible to drive a car or truck, with certain restrictions, also when inflation pressure is very low or non-existing (after tire damage). Rolling resistance of tires rolling the inserts increases considerably in relation to the rolling resistance of properly inflated tires. This paper presents results...
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Diffusible Hydrogen Control in Flux Cored Arc Welding Process
PublicationOne of the types of hydrogen degradation of steel welded joints is cold cracking. The direct cause of the formation of cold cracks is simultaneous presence of hydrogen, residual stresses and brittle structure. The way of preventing the occurring of degradation is to eliminate at least one of these factors. Practice has shown that the best solution is to control the amount of hydrogen in deposited metal. In this paper an experimental...
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Modal parameters identification with Particle Swarm Optimization
PublicationThe paper presents method of the modal parameters identification based on the Particle Swarm Optimization (PSO) algorithm [1]. The basic PSO algorithm is modified in order to achieve fast convergence and low estimation error of identified parameters values. The procedure of identification as well as algorithm modifications are presented and some simple examples for the SISO systems are provided. Results are compared with the results...
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Road texture influence on tire rolling resistance
PublicationTire rolling resistance is one of the most important resistive forces acting on road vehicles. It depends on tire and surface characteristics as well as vehicle operating parameters. This paper deals with the influence of road surface texture on rolling resistance of passenger car tires. Results of road measurements performed on variety of road surfaces are presented.
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Analysis and Comparison of Safety of Children and Adult Passenger in Car Based on Crash Tests Results
PublicationMost important features of the child seat were presented. There was made analysis of selected dynamic loads acting on mannequins heads during a collision. Comparison of loads acting on the kid in a child seat and the other passengers in a car is presented. In analysis of the results particular attention has been paid on the children's secure in a car. The phenomena of collision child's occipital bone with seat backrest was described....
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Free convection of water-Al2O3 nanofluid from horizontal porous coated tube
PublicationNanofluids are expected to enhance heat transfer in many thermal systems. Present efforts are concentrated on boiling heat transfer of nanofluids, although single phase convection is of key importance in various appliances such as car radiators or heating systems. This paper presents experimental results of heat transfer during free convection of water-Al3O3 nanofluid from horizontal tube covered with metallic porous coating. Contrary...
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Wettability of Horizontal Stainless Steel Tube by Nanofluid Droplets
PublicationThe goal of the present work was the experimental determination of the contact angle of three nanofluids, i.e. water-Al2O3, water-Cu and water-TiO2 on horizontal stainless steel tube of 1.6 mm OD. Of particular interest was the effect of nanoparticle concentration (0.01%, 0.1%, and 1% by weight) on droplet contact angle.
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Damage-involved response of two colliding buildings under non-uniform earthquake loading
PublicationPounding between insufficiently separated buildings, which may result in considerable damage or may even lead to the total collapse of colliding structures, has been repeatedly observed during earthquakes. Earthquake-induced collisions of buildings has been intensively studied applying various structural models. It was assumed in the analyses, however, that the seismic excitation is identical for all structural supports; whereas,...
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Generative Process Planning with Reasoning based on Geometrical Product Specification
PublicationThe focus of this paper is on computer aided process planning for parts manufacture in systems of definite process capabilities, involving the use of multi-axis machining centers for parts shaping and grinding machines for finishing. It presents in particular a decision making scheme for setup determination as a part of generative process planning. The planning procedurę consists of two stages. The first stage is associated with...
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Frequency response spectra applied to assess efficiency of the training techniques
PublicationThe purpose of the research is to assess the increase of the muscle strength and power. Movement of the human body when the moving one impacts a stationary or moving body is taken under consideration. The waveform produced by an impact is transformed into frequency domain. The acceleration record is transformed as a complex spectrum, by the use of a Discrete Fourier Transformation. In this paper the applications of the discrete...
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On Software Unit Testing For Improving Security And Performance Of Distributed Applications
PublicationPerformance and security are software (SW) application attributes situated on the opposite corners of system design. In the most drastic example the most secure component is the one totally isolated from the outside world, with communication performance reduced to zero level (e.g. disconnected physically from the network, placed inside a Faraday cage to eliminate possible wireless accessibility). On the other hand the most performance-optimized...
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The analysis of turbine propulsion systems in nuclear submarines
PublicationThe article systematises submarines, which are presently in service, according to their propulsion types (both conventional and nuclear), power output, and submersion depth. Contemporary types of propulsion systems installed and used in submarines are discussed. Calculations were performed for the PWR (Pressurized Water Reactor) type nuclear propulsion system and the supercritical turbine propulsion system (supercritical reactor...
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Carbon dioxide potential reduction using Start-Stop system in a car
PublicationOperating fuel consumption increases significantly when the vehicle stops frequently while driving or when the engine is idling during braking. In such cases, the internal combustion engine consumes the fuel but the mechanical energy is not used by the drive system. The amount of fuel that is consumed in this time by the engine can potentially be saved if the car is equipped with a Stop-Start system. Start-Stop system automatically...
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Effect of surface roughness on thermal-hydraulic characteristics of plate heat exchanger
PublicationIn the paper the experimental analysis of passive heat transfer intensification in the case of modeled plate heat exchanger is conducted. The plate heat exchanger is chosen for the analysis because this kind of heat exchangers could be prospectively applied in the ORC systems, however other areas or application are equally possible. The experimental setup was assembled at the Department of Energy and Industrial Apparatus of Gdansk...
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Organic Rankine as bottoming cycle to a combined Brayton and Clausius-Rankine cycle
PublicationThis paper presents an enhanced approach, as it will be considered here that the ORC installation could be extra-heated with the bleed steam, a concept presented by the authors. In such way the efficiency of the bottoming cycle can be increased and an amount of electricity generated increases. A thermodynamic analysis and a comparative study of the cycle efficiency for a simplified steam cycle cooperating with ORC cycle will be...
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The initial selection of parameters for dynamic brake for car engine test dynamometer
PublicationThe article presents an analysis of the car engine loads. The aim of the analysis was to determine the parameters of the brake / electric motor on an engine test bad. Analysis of loads on the driving tests concerned on chassis dynamo to simulate them on an engine dynamometer. To check the range of dynamometer shaft angular acceleration inertial mass of a car was reduced on the crankshaft axis. The calculations of maximum shaft...
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Validation of polyurethane-wood composites properties
Open Research DataThis study focuses on the development of the PU-WC manufacturing method, the determination of properties of this type of composite, and the indication of its potential application. The mechanical properties of PU-WC were characterized by flexural tests. To determine the thermal properties, dynamic mechanical analysis (DMA) and thermogravimetric analysis...
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Bromidotetrakis(2-ethyl-1H-imidazole-κN3)copper(II) bromide
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An efficient molecular docking using conformational space annealing
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Bromidotetrakis(2-ethyl-1H-imidazole-KN3)copper(II) bromide
PublicationThe CuII ion in the title complex, [CuBr(C5H8N2)4]Br, is coordinated in a square-pyramidal geometry by four N atoms of imidazole ligands and one bromide anion in the apical position. In the crystal, the ions are linked by a 3-D network of N-H---Br and CH---Br hydrogen bonds.
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Determination of the width of the carrier recombination zone in organiclight emitting diodes.
PublicationW pracy mierzono kwantową wydajność elektroluminescencji w diodach dwuwarstwowych z różną grubością emitera w postaci warstwy hydroksychinolinowego kompleksu aluminium (Alq3). Stwierdzono, że szerokość strefy rekombinacji ładunku maleje ze wzrostem natężenia pola elektrycznego od 70 nm(dla E=0.75MV/cm do 40 nm (dla E=1.MV/cm).
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Systemy Smart Cities - studium przypadku
PublicationThe paper presents the architecture of an enterprise service bus used in the construction of information systems processing large amounts of data for decision-making needs at the City Hall in Gdańsk. The key concept of processes of bus development involves installation of developing environment, database connection, flow mechanisms and data presentation. The issue was supported by models such as KPI (Key Processes Identifier) and...
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GPU-accelerated finite element method
PublicationIn this paper the results of the acceleration of computations involved in analysing electromagnetic problems by means of the finite element method (FEM), obtained with graphics processors (GPU), are presented. A 4.7-fold acceleration was achieved thanks to the massive parallelization of the most time-consuming steps of FEM, namely finite-element matrix-generation and the solution of a sparse system of linear equations with the...
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The Point Estimate Method in a Reticulated Shell Reliability Analysis
PublicationThe objective of this paper is to present an application of the point estimate method (PEM) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications
PublicationIn this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy...
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Mikrostruktura kompozytów poliestrouretanowo-gumowych wulkanizowanych siarką o różnej zawartości recyklatu gumowego
PublicationIntensywny rozwój przemysłu motoryzacyjnego szczególnie widoczny w przeciągu ostatnich kilkudziesięciu lat w krajach silnie rozwijających się na całym świecie, w tym również w Polsce generuje powstawanie coraz większej ilości poeksploatacyjnych opon samochodowych. Statystyki podają, że co roku w Polsce przybywa ok. 259 tys. ton poużytkowych opon samochodowych, w tym, ok. 16 tys. ton jest poddawane bieżnikowaniu, ok. 53 tys. ton...
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Various types of semiconductor photocatalysts modified by CdTe QDs and Pt NPs for toluene photooxidation in the gas phase under visible light
PublicationA novel synthesis process was used to prepare TiO2 microspheres, TiO2 P-25, SrTiO3 and KTaO3 decorated by CdTe QDs and/or Pt NPs. The effect of semiconductor matrix, presence of CdTe QDs and/or Pt NPs on the semiconductor surface as well as deposition technique of Pt NPs (photodeposition or radiolysis) on the photocatalytic activity were investigated. The as-prepared samples were characterized by X-ray powder diffractometry (XRD),...
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The effects of bifunctional linker and reflux time on the surface properties and photocatalytic activity of CdTe quantum dots decorated KTaO3 composite photocatalysts
PublicationNovel CdTe-KTaO3composite photocatalysts were successfully synthesized by using thioglycolic acid(TGA) or 3-mercaptopropionic acid (MPA) as linker molecules which facilitated attachment of CdTequantum dots to the surface of KTaO3nanocubes. The as-prepared photocatalysts were characterizedby UV–vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy...