Wyniki wyszukiwania dla: THERMAL EFFECTS
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Tropospheric thermal field variability over Poland in the context of climate change
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Chemical and thermal stability of core-shelled magnetite nanoparticles and solid silica
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New components for hydraulic drive systems and their performance in thermal shock conditions
PublikacjaArtykuł prezentuje konstrukcję pomp z rozrządem krzywkowym typu PWK o zmiennej wydajności wraz ze wstępnymi wynikami badań prototypu PWKZ-78. Przedstawiono także wstępne wyniki analiz MES i CFD zjawisk zachodzących w pracującej pompie. W drugiej części zaprezentowano metodykę badań zachowania się pomp w warunkach szokutermicznego i wyniki uzyskane dla pompy typu PWK.
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Thermal Stability of Multicomponent Layers Created with the Hybrid Method on Aluminium Base
PublikacjaW pracy przedstawiono skład fazowy, mikrostrukturę oraz graficzny i matematyczny opis kinetyki utleniania wieloskładnikowych warstw powierzchniowych wytworzonych na aluminiowym podłożu.
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Thermal properties of polyurethanes synthesized using waste polyurethane foam glycolysates
PublikacjaW pracy przedstawiono wyniki analizy termicznej (DMTA i TG-FTIR) glikolizatów i otrzymanych z nich poliuretanów. Glikolizaty uzyskiwano w reakcji odpadowej pianki poliuretanowej z 1,6 heksametylenodiolem (HDO) przy różnym stosunku masowym pianki do HDO (1:1 - 10:1). Poliuretany syntezowano metodą dwuetapową z prepolimeru (diizocyjanian MDI + glikolizat), który przedłużano handlowym małocząsteczkowym glikolem.
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Heteroleptic tri-tert-butoxysilanethiolate complexes of manganese(II) - thermal studies
PublikacjaThe thermal behavior of Mn(II) silanethiolate series [Mn(SR)2L(MeOH)n], where R=SSi(OBut)3, L=heterocyclic nitrogen base and n=0, 1 or 2 has been comparatively investigated using differential scanning calorimetry (DSC), thermogravimetry (TG) and TG-infrared spectoscopy (IR) techniques. The TG curves indicate the differences in the thermal decomposition due to presence of distinct N-donor ligands and labile MeOH molecules coordinated...
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Thermal properties of rare earth elements complexes with 1,3,5-benzenetricarboxylic acid
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Influence of chemical composition of amide block on the thermal properties and structure of terpolymers
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Effect of Thermal Processing on Antioxidant Activity and Cytotoxicity of Waste Potato Juice
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Analysis of the posibbility of detect determination using cold excitation in thermal tomography
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Thermal degradation of poly(alkyl methacrylates) and polyurethane pressure-sensitive adhesives
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Thermal degradation of butyl acrylate-methyl acrylate-acrylic acid-copolymers
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The Influence of Silica Fume on the Mechanical and Thermal Parameters of Portland Cement Concretes
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Continuous and catalyst free synthesis of graphene sheets in thermal plasma jet
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Face with Mask Detection in Thermal Images Using Deep Neural Networks
PublikacjaAs the interest in facial detection grows, especially during a pandemic, solutions are sought that will be effective and bring more benefits. This is the case with the use of thermal imaging, which is resistant to environmental factors and makes it possible, for example, to determine the temperature based on the detected face, which brings new perspectives and opportunities to use such an approach for health control purposes. The...
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TESTING CONTRACTION AND THERMAL EXPANSION COEFFICIENT OF CONSTRUCTION AND MOULDING POLYMER COMPOSITES
PublikacjaThe paper presents results of systematic tests of contraction and thermal expansion coefficients of materials based on polymer composites. The information on the above material properties is essential both at the design stage and during the use of finished products. Components for the samples were selected in such a way as to represent typical materials used for production of construction and moulding elements. The performed tests...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublikacjaIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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Effect of double thermal and electrochemical oxidation on titanium alloys for medical applications
PublikacjaThe research focuses on the development and characterization of innovative thin hybrid oxide coatings obtained in subsequent processes of thermal (TO) and electrochemical (EO) oxidation. Four different surface modifications were investigated and the microstructure was determined, the mechanical, chemical and biological properties of the Ti-13Nb-13Zr alloy were assessed using scanning electron microscopy, X-ray dispersion analysis,...
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Perfect thermal contact of hyperbolic conduction semispaces with an interfacial heat source
PublikacjaThe problem of thermal contact between two bodies with a heat source at their interface presents great scientific and practical interest. On the time scale of a nanosecond or shorter, heat propagation should be considered in the form of thermal waves of finite speeds. This study investigated the thermal behaviour of hyperbolic conduction semispaces in perfect thermal contact subjected to the action of an interfacial heat source....
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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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PROCESSING, MECHANICAL AND THERMAL PROPERTIES OF RECYCLED LOW-DENSITY POLYETHYLENE STREAMS
PublikacjaThe 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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Thermal and technological aspects of double face grinding of C45 carbon steel
PublikacjaIn grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the...
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Thermal and technological aspects of double face grinding of Al2O3 ceramic materials
PublikacjaDouble face grinding with planetary kinematics is a process to manufacture workpieces with plan parallel functional surfaces, such as bearing rings or sealing shims. In order to increase the economic efficiency of this process, it has to be advanced permanently. The temperature in the contact zone of most grinding processes has a huge influence on the process efficiency and the workpiece qualities. In contrast to most grinding...
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Nonlinear Interaction of Modes in a Planar Flow of a Gas with Viscous and Thermal Attenuation
PublikacjaThe nonlinear interaction of wave and non-wave modes in a gas planar flow are considered. Attention is mainly paid to the case when one sound mode is dominant and excites the counter-propagating sound mode and the entropy mode. The modes are determined by links between perturbations of pressure, density, and fluid velocity. This definition follows from the linear conservation equations in the differential form and thermodynamic...
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Deep learning based thermal image segmentation for laboratory animals tracking
PublikacjaAutomated systems for behaviour classification of laboratory animals are an attractive alternative to manual scoring. However, the proper animals separation and tracking, especially when they are in close contact, is the bottleneck of the behaviour analysis systems. In this paper, we propose a method for the segmentation of thermal images of laboratory rats that are in close contact during social behaviour tests. For this, we are...
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A simple modification of PCR thermal profile applied to evade persisting contamination
PublikacjaThe polymerase chain reaction (PCR), one of the most commonly applied methods of diagnostics and molecular biology has a frustrating downside known as the false positive signal or contamination. Several solutions to avoid and to eliminate PCR contaminations have been worked out to date but the implementation of these solutions to laboratory practice may be laborious and time consuming. A simple approach to circumvent the problem...
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Thermal-Resistant Polyurethane/Nanoclay Powder Coatings: Degradation Kinetics Study
PublikacjaIn the present study, thermal degradation kinetics of polyurethane (PU) powder coatings reinforced with organo-modified montmorillonite (OMMT) was investigated. PU nanocomposites were prepared in different concentrations of 1, 3, and 5 wt.% of OMMT via the extrusion method. The microstructure of the nanocomposites was observed by scanning electron microscope (SEM) illustrating uniform dispersion of OMMT nano-clay platelets in the...
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Could thermal imaging supplement surface electromyography measurements for skeletal muscles?
PublikacjaAbstract—(1) Background: The aim of this study is to present the results of experiments in which surface electromyography (sEMG) and thermal imaging were used to assess muscle activation during gait and to verify the hypothesis that there is a relationship in the case of low fatigue level between sEMG measured muscle activation, assessed in the frequency domain, and thermal factors calculated as minimum, maximum, kurtosis, mean,...
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Evaluation of Thermal Stresses in Asphalt Layers in Comparison with TSRST Test Results
PublikacjaThe paper presents the results of calculations and laboratory determination of thermal stresses at low temperatures. The modified Hills and Brien's method was used to calculate the thermal stresses in asphalt layers of pavements and the results were compared against the values obtained at a laboratory with the Thermal Stress Restrained Specimen Test (TSRST) method. The laboratory investigations were conducted using plain grade...
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Respiratory Rate Estimation Based on Detected Mask Area in Thermal Images
PublikacjaThe popularity of non-contact methods of measuring vital signs, particularly respiratory rate, has increased during the SARS-COV-2 pandemic. Breathing parameters can be estimated by analysis of temperature changes observed in thermal images of nostrils or mouth regions. However, wearing virus-protection face masks prevents direct detection of such face regions. In this work, we propose to use an automatic mask detection approach...
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Evaluation of thermal cracking probability for asphalt concretes with high percentage of RAP
PublikacjaThe paper presents determination of the probability of thermal cracking of asphalt mixtures with different reclaimed asphalt pavement (RAP) content on the basis of laboratory tests and analytical evaluation using thermal stress development method. Probability was evaluated taking into consideration: the type and gradation of the mixture and the quality and content of RAP. Thermal stresses were determined using two models: elastic and...
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Study of the influence of thermal factors on the welding process of polyethylene gas pipelines,
PublikacjaA one-dimensional calculation scheme is proposed with the help of which it is possible to determine and set the technological parameters with the accuracy to be realized in production conditions: the temperature of the heating element and the heating time, which allows maximum mechanization of the technological operations of polyethylene gas pipelines welding. The numerical value of the coefficient of temperature for polyethylene...
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The effect of laser on metal surfaces for multidisciplinary usage in material and thermal engineering
PublikacjaThe subject of heat transfer and cooling systems is still a matter of contention in many different fields of science and industry. Infrigidation is much more difficult than warming, and so, much more needed in more and more different devices, starting from massive industrial machinery and air conditioning in commercial buildings, up to micro and nano-surgery tools. In fact, the size of many cooling systems is still a problem. It...
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The effect of thermal modification on the quality of the milled surface of beech and pine wood
PublikacjaThe article deals with the effect of thermal modification on the quality of the created surface during milling on CNC milling cutters. The quality of the created surface is evaluated based on surface roughness, specifically its roughness parameter Ra. The observed surface is created by a shank cutter with a diameter of 20 mm and three cutting edges in a spiral at a standard speed of 18,000. min-1. The article compares thermally...
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On thermal and Flow Expert Systems Based on Artificial Neural Network (ANN)
PublikacjaZaprezentowano możliwość realizacji jednego z zadań systemów eksperckich, polegającego na określaniu rozmiaru eksploatacyjnej degradacji parametrów geometrycznych układów łopatkowych turbin. Dyskusję przeprowadzono w oparciu o zastosowanie wybranego typu sztucznej sieci neuronowej (SSN). Badano jakość i dokładność polegającą na dobrej identyfikacji rozmiaru degradacji przez tę wybraną SSN wykrywającą rozmiar degradacji geometrycznej....
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The influence of the welding thermal cycles on corrosion resistance of duplex stainless steel
PublikacjaBadano skłonnośc strefy wpływu ciepła spoin ze stali dupleks do korozyjnego pękania narężeniowego. Wykonano próby korozyjne z wykorzystaniem metody SSRT w środowisku korozyjnym wrzącego MgCl2. Wykazano, że duży udział ferrytu w strukturze SWC pogarsza odpornośc na korozję. Badania metalograficzne na mikroskopie lektronowym wykazały różne sposoby propagacji pęknięcia zależnie od zawartości austenitu w strukturze SWC.
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Investigations to realize thermal, humid and human comfort in modern living houses.
PublikacjaPrzedstawiono badania nad komfortem cieplnym, wilgotnościowym i psychicznym w domkach mieszkalnych. Wykonano pomiary oraz przeprowadzono ankiety. Zastosowano różne sposoby wentylacji.
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The study on application of biopolyols obtained by cellulose biomass liquefaction performed with crude glycerol for the synthesis of rigid polyurethane foams
PublikacjaIn this work rigid polyurethane foams (PUR) were obtained by replacement of 0–70 wt% of petrochemical polyol with bio-polyol obtained via cellulose liquefaction in presence of crude glycerol. The foams with different content of a bio-polyol were prepared by single step method for NCO/OH ratio equals 1.5. The prepared materials were analyzed in terms of their morphology, chemical structure, thermal stability and basic physical and...
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Photovoltaic Roof Tiles: The Influence of Heat Recovery on Overall Performance
PublikacjaA photovoltaic (PV) roof tile serves both as a roofing material and as an electricity-producing surface. The main aim of the present study was to increase the overall system efficiency of PV tiles by using heat recovery. The chosen strategy was two-fold: determine the operational efficiency of PV tiles and optimize construction to increase the cooling effect when using air as the working medium. A detailed experimental study was...
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Determinants of the surface quality, density and dimensional correctness in selective laser melting of the Ti-13Zr-13Nb alloy
PublikacjaSelective laser melting is widely used for custom-designed elements. Successful manufacturing depends on laser treatment parameters and material features. This research aimed to determine the effects of laser power, scan time and hatch distance on surface quality, relative density and dimensional precision for cuboids made of the Ti-13Zr-13Nb alloy. The influence of energy density, energy flux and pre-heating was seen to be decisive...
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The Influence of Substitution of a Phosphorus-Containing Polyol with the Bio-polyol on the Properties of Bio-based PUR/PIR Foams
PublikacjaIn this work, effects of incorporating of a phosphorus-containing polyol into rigid polyurethane/polyisocyanurate foams’ formulations developed with use of two different bio-based polyols, derived from crude glycerol or liquefied cellulose were examined. The bio-polyol derived from crude glycerol was synthesized via two-step process from crude glycerol and castor oil, whereas the bio-polyol derived from liquefied cellulose was...
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Phase Change Thermal Energy Storage – The Experience of the Materials Preparation for the Specific Applications.
PublikacjaThermal energy storage and temperature stabilization is very important in many engineering applications. There are three kinds of thermal energy storage: sensible heat storage, latent heat storage and reversible chemical reaction heat storage. Phase change materials (PCM) absorb, store and release large amounts of energy in the form of latent heat, at constant temperature, called the transition temperature. The amount of heat...
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Accuracy Investigations of Turbine Blading Neural Models Applied to Thermal and Flow Diagnostics
PublikacjaPossibility of replacing computional fluid dynamics simulations by a neural model for fluid flow and thermal diagnostics of steam turbines is investigated. Results of calculations of velocity magnitude of steam for 3D model of the stator of steam turbine is presented.
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Effect of sisal fiber filler on thermal properties of bio-based polyurethane composites
PublikacjaThis work is mainly focused on study of thermal and thermomechanical properties of obtained bio-based polyurethane (coded as bio-PU) composites via using different types of bio-components (bio-glycol, modified soybean oil and sisal fiber) in the procedure. The chemical structure, morphology and mechanical properties were also investigated and described in this manuscript in order to know more perfect characterization of produced...
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Numerical and experimental investigation of thermal convection near electric devices with vertical channels
PublikacjaThis paper presents the results of numerical and experimental investigation of thermal convection near heat emitting surfaces of an electric device. For the intensification of thermal convection, special vertical channels were formed near the heat emitting surfaces of the device. An experimental test has proved that there is an optimal length of the channels – thermal convection is the most intensive then. Air velocity vectors...
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Thermal performance of a prototype plate heat exchanger with minichannels under boiling conditions
PublikacjaTo solve the problem and to meet the requirements of customers in the field of high heat fluxes transfer in compact units, a new design of plate heat exchanger with minichannels (minichannels PHE) was proposed. The aim was to construct a compact heat exchanger of high effectiveness for the purpose of household cogeneration ORC system. In this paper the experimental analysis of an assembled prototype of such compact heat exchanger...
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Automatic analysis of the aggressive behavior of laboratory animals using thermal video processing
PublikacjaThe bite detection is very important but difficult element of the social interaction analysis. Standard observation methods like human observer or a camcorder of visible light frequencies fail in this case. However, it is possible to discern cooler spots on the rodent's body that appear after body contact with another individual, and vanish after short time. These spots are assumed to be a saliva trace left on fur after bite. In...
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Design analysis of ORC micro-turbines making use of thermal energy of oceans
PublikacjaThe article presents the results of the analysis of energy conversion cycles making use of thermal energy of oceans. The objects of analysis were two cases of closed Organic Rankine Cycle (ORC) power plants, which were: the cycle in which the vapour of the working medium was produced by warm oceanic water in the circum-equatorial zone, and the so-called “arctic” cycle in which this vapour was produced by non-frozen water in the circumpolar...
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Phase change thermal energy storage – the experience of the materials preparation for the specific applications.
PublikacjaThermal energy storage and temperature stabilization is very important in many engineering applications. There are three kinds of thermal energy storage: sensible heat, latent heat and reversible chemical reaction heat. Phase change materials (PCM) absorb, store and release large amounts of energy in the form of latent heat, at constant temperature, called the transition temperature. Many innovative applications could be found...
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublikacjaThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...