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Search results for: THERMAL PROPERTIES
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Perfect thermal contact of hyperbolic conduction semispaces with an interfacial heat source
PublicationThe 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
PublicationA 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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Investigation of the thermal effects in water-lubricated journal bearings with axial grooves
PublicationWater-lubricated hydrodynamic journal bearings are frequently applied as stern tube bearings due to their advantages over other bearing types. They are environmentally friendly, can operate without sealings and in conditions of low friction losses. The most popular are bearings with open axial grooves, which require, for proper operation, forced axial flow of the lubricating water. Correctly designed and operated stern tube bearings...
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The effect of laser on metal surfaces for multidisciplinary usage in material and thermal engineering
PublicationThe 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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Study of the influence of thermal factors on the welding process of polyethylene gas pipelines,
PublicationA 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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Nonlinear Interaction of Modes in a Planar Flow of a Gas with Viscous and Thermal Attenuation
PublicationThe 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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Thermal and technological aspects of double face grinding of Al2O3 ceramic materials
PublicationDouble 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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On thermal and Flow Expert Systems Based on Artificial Neural Network (ANN)
PublicationZaprezentowano 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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Face with Mask Detection in Thermal Images Using Deep Neural Networks
PublicationAs 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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The effect of thermal modification on the quality of the milled surface of beech and pine wood
PublicationThe 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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Respiratory Rate Estimation Based on Detected Mask Area in Thermal Images
PublicationThe 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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Investigations to realize thermal, humid and human comfort in modern living houses.
PublicationPrzedstawiono badania nad komfortem cieplnym, wilgotnościowym i psychicznym w domkach mieszkalnych. Wykonano pomiary oraz przeprowadzono ankiety. Zastosowano różne sposoby wentylacji.
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Janusz Cieśliński prof. dr hab. inż.
PeopleHe was born on April 15, 1954 in Slupsk. He graduated from the Faculty of Mechanical Engineering at Gdańsk University of Technology (1978). In 1986 he received the title of Doctor, in 1997 he obtained the title of Ph.D. with habilitation, and in 2006 he received the title of Professor. He worked as head of department and vice-dean for Education at the Faculty of Mechanical Engineering for two terms (2002-2008). His research interests...
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Reviewing the recent developments of using graphene-based nanosized materials in membrane separations
PublicationAccording to the potentialities of graphene-based materials and their unique physicochemical properties. Such 2D nanomaterials are likely to be the most implemented within the improvement of the selective separations of polymer membranes, together with enhanced physicochemical properties (such as hydrophilicity/hydrophobicity, transport of molecules, mechanical and thermal features, among others). Hence, this review compiles and...
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A new diagnostic method for evaluation of cardiosurgery wound healing
PublicationOne of important and still unsolved problems in medicine is the question of objective and quantitative evaluation of post-surgery wound healing. The aim of this research is to analyse possibility and value of using the newly elaborated infrared imaging procedure – Active Dynamic Thermography (ADT) – for quantitative description of wound healing processes in cardiosurgery. Both, classical thermal figures of merit as well as ADT...
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Acoustic heating produced in the boundary layer
Publication: Instantaneous acoustic heating of a viscous fluid flow in a boundary layer is the subject of investigation. The governing equation of acoustic heating is derived by means of a special linear combination of conservation equations in the differential form, which reduces all acoustic terms in the linear part of the final equation but preserves terms belonging to the thermal mode. The procedure of decomposition is valid in a weakly...
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Fabrication of toughened plastic using styrene butadiene rubber-poly (methyl methacrylate) interpenetrating polymer networks
PublicationA standard set of interpenetrating polymeric networks (IPNs) has been contrived using an elastomerstyrene butadiene rubber and a thermoplastic poly (methyl methacrylate) through sequential polymerization protocol. This low-cost material can be hopefully engaged as a toughened plastic with cocontinuous morphology. Different morphological protocols including Raman imaging are effectively utilized to envisage the effect of blend ratio...
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Novel cast polyetherurethanes based on dispersed polymeric polyols
PublicationOur study was focused on obtaining polyetherurethanes synthesized with using polymeric polyether based polyols differing in dispersed copolymer content (10, 20 and 40 wt%). The polyetherurethane materials were synthesized via two step method. The influence of different polymeric polyether based polyols on the chemical structure, morphology, mechanical and thermal properties of the obtained polyetherurethanes was investigated. The...
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New 3D printable filaments with nanodiamonds, physicochemical additives characteristics and electrochemical activity
Open Research DataThis dataset contains the physicochemical analyses (XRD, Raman spectroscopy, BET analyses) and electrochemical analyses (CV, EIS) for a new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added...
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Thermal behavior of TeOx xerogel powder under different atmospheres
Open Research DataThe DataSet contains the results of the thermal behavior of the TeOx xerogel powder measured under different atmospheres. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. The sol was obtained by vigorously stirring precursor solution...
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Determination of t8/5 cooling times for underwater local dry welding of steel
PublicationKnowledge of thermal history is the basic condition for studying the structure - properties of welded joints. The determinant of thermal history is the thermal cycle, whose in-situ measurements are still a big challenge. Water as the welding environment complicates this issue even more. The article presents a method to determine an equation for calculating t8/5 cooling times for underwater gas metal arc welding of unalloyed steels...
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Towards understanding the role of peroxide initiators on compatibilization efficiency of thermoplastic elastomers highly filled with reclaimed GTR
PublicationThermoplastic elastomers based on recycled high density polyethylene (rHDPE) and styrene-butadiene-styrene (SBS) block copolymer were highly filled with reclaimed ground tire rubber (RR). The impact of various organic peroxides (dicumyl peroxide (DCP), benzoyl peroxide (BP) and di-tert-butyl peroxide (DB)), applied as free-radical initiators, on the processing, structure and performance properties of rHDPE/SBS/RR blends was investigated....
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Single-phase product obtained via crude glycerine depolymerisation of polyurethane elastomer: structure characterisation and rheological behaviour
PublicationPolyurethane recycling is a topic of growing interest due to the increasing amount of polyurethanewaste. The main purpose of polyurethane feedstock recycling is to recover the starting polyol, a valuable material. In thiswork, amethod of polyurethane thermo-chemical recycling, glycerolysisbymeansof crude glycerine, is proposed. Themaineffort is focusedonthe employment of crude glycerine without purification from biodiesel production...
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Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces: extrusion and characterisation of filaments for improved 3D-printed surfaces
PublicationA new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added as fillers in poly(lactic acid) (PLA)-based composites to extrude 3D filaments. Carbon black served as a primary filler to reach high composite conductivity at low diamondised nanocarbon concentrations (0.01 to 0.2...
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Progressing Pollutant Elution from Snowpack and Evolution of its Physicochemical Properties During Melting Period— a Case Study From the Sudetes, Poland
PublicationMain aim of the work assumed recognition of physicochemical changes in snowpack occurring during the melting period. Properties of snow cover had been identified at two sites in Western Sudetes mountains (860 and 1228 m asl) in SW Poland since the end of January, and monitored until the disappearance of snow in late Spring. Snow pit measurements and sample collection at both sites were made followed by chemical analyses with the...
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Processing and structure–property relationships of natural rubber/wheat bran biocomposites
PublicationIn this work, wheat bran was used as cellulosic filler in biocomposites based on natural rubber. The impact of wheat bran content [ranging from 10 to 50 parts per hundred rubber (phr)] on processing, structure, dynamic mechanical properties, thermal properties, physico-mechanical properties and morphology of resulting biocomposites was investigated. For better characterization of interfacial interactions between natural rubber...
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Thermal stability of V2O5 nanorods under inert atmosphere
Open Research DataThe DataSet contains the TGA curves of V2O5 nanorods obtained at 650°C. The information about nanorods synthesis is described in the Journal of Nanomaterials.
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Thermal stability of V2O5 nanorods under oxidizing atmosphere
Open Research DataThe DataSet contains the TGA curves of V2O5 nanorods obtained at 650°C. The information about nanorods synthesis is described in the Journal of Nanomaterials.
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IMPACT-TOUGHNESS INVESTIGATIONS OF DUPLEX STAINLESS STEELS
PublicationDuplex stainless steels are very attractive constructional materials for use in aggressive environments because of their several advantages over austenitic stainless steels. Duplex steels have excellent pitting and crevice corrosion resistance, are highly resistant to chloride stress-corrosion cracking and are about twice as strong as common austenitic steels. Better properties are associated with their microstructures consisting...
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A review: Fabrication of porous polyurethane scaffolds
PublicationThe aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical...
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublicationBulk metallic glasses (BMGs) have gained a lot of attention in recent years due to their outstanding properties such as high hardness and excellent wear and corrosion resistance. However, they are restricted in industrial applications due to their extreme brittleness. Iron based amorphous coatings from BMGs are the best solution to use them by overcoming the problem of extreme brittleness. The coatings can be sprayed by various...
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Ground Tire Rubber Filled Flexible Polyurethane Foam—Effect of Waste Rubber Treatment on Composite Performance
PublicationThe application range of flexible polyurethane (PU) foams is comprehensive because of their versatility and flexibility in adjusting structure and performance. In addition to the investigations associated with further broadening of their potential properties, researchers are looking for new raw materials, beneficially originated from renewable resources or recycling. A great example of such a material is ground tire rubber (GTR)—the...
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Synthesis of isotactic polypropylene- block -polystyrene block copolymers as compatibilizers for isotactic polypropylene/polyphenylene oxide blends
PublicationPoly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and isotactic polypropylene (iPP) are highly incompatible and consequently their uncompatibilized blends are quite brittle regardless of the molecular weights and ductility of the individual components. Isotactic polypropylene-polystyrene block copolymers, to be applied as compatibilizers for a broad range of PPO/iPP blend compositions, were prepared by mechanism transformation from...
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Graphene Reinforced Phenolic Foams
PublicationPhenolic foams (PF) belong to the polymeric materials, which are very attractive from the point of many possible applications such as insulation or fire protection materials. This chapter attempts to explain the influence of graphene and graphene derivatives on the phenolic foams. This work briefly presents different graphene nanoparticles introduced to the phenolic foams matrix, in terms of impact on the thermal, mechanical, and...
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Thermal behaviour of vanadium xerogel powder under different inert atmosphere
Open Research DataThe DataSet contains the results of the thermal behavior of the vanadium xerogel powder. The information about xerogel powder synthesis is described in the Journal of Nanomaterials.
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Efficiency of acoustic heating produced in the thermoviscous flow of a fluid with relaxation
PublicationInstantaneous acoustic heating of a fluid with thermodynamic relaxation is the subject of investigation. Among others, viscoelastic biological media described by the Maxwell model of the viscous stress tensor, belong to this type of fluid. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in...
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By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood–Polymer Composites
PublicationThe present paper describes the application of two types of food-industry by-products, brewers’ spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood–polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting...
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MANDARIN PEEL AS AN AUSPICIOUS FUNCTIONAL FILLER FOR POLYMER COMPOSITES
PublicationThis work describes the application of mandarin peel (MP) as a waste filler for high-density polyethylene (HDPE) composites. The main goal was to investigate the impact of the filler's essential oils, which include multiple terpenes and terpenoids, on the processing, physicochemical, mechanical, and thermal properties of the composites as a function of different filler content (1 – 10 wt%), as well as its effect on the color and...
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Fabrication and Characterization of Green Polyurethane Foams with Enhanced Vibration Damping Capability
PublicationOver the past decades, there has been an intensive development of the technologies and innovations aimed at increasing the quality of life. This development largely concerns the comfort of use of everyday products that, among others, are products of the automotive, construction, or furniture industries. Considering the increase in the comfort of using products such as cars, houses, and flats, one of the comfort features of their...
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Distribution and concentration of heavy metals in ash during thermal process sewage sludge
PublicationKażdego roku na świecie, obserwuje się znaczący wzrost produkcji osadów ściekowych. Przykładowo w 2006 roku, w Polsce ich ilość osiągnęła 1 mln ton w przeliczeniu na sucha masę, w tym ok. połowa pochodziła z oczyszczalni komunalnych. Problem ich zagospodarowania stanowi przedmiot zainteresowania wielu instytucji zajmujących się ochroną środowiska, zarówno w Polsce, jak i na całym świecie. Ich dotychczasowe wykorzystania polegało...
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On the inappropriate fit of diffusion functions at thermal decomposition of some azomonoethers in liquid state
PublicationW celu analizy rozkładu termicznego tytułowych barwników azowych zastosowano mechanizmy D1, D2, D3 i D4. W wyniku przeprowadzonych badań stwierdzono, że rozkład zachodzi w fazie ciekłej, zaś w celu wyznaczenia parametrów aktywacji oraz wyznaczenia funkcji przemiany zastosowano koncepcje homo- i heterogeniczne.
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Laser Investigations of Flow Patterns in Electrostatic Precipitators and Non Thermal Plasma Reactors
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Chemical, thermal and laser processes in recycling of photovoltaic silicon solar cells and modules
PublicationIn recent years, photovoltaic power generation systems have been gaining unprecedented attention as an environmentally beneficial method to solve the energy problem. From the economic point of view the pure silicon, which can be recapture from the used cells, is the most important material due to its cost and shortage. In the paper selected methods of used or damaged module and cells recycling and experimental results are presented....
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Enhancement of thermal stability of multiwalled carbon nanotubes via different silanization routes
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The effect of nanomaterials on thermal resistance of cement-based composites exposed to elevated temperature
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Study of pozzolanic action of ground waste expanded perlite by means of thermal methods
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Detection of thermal radiation using lanthanum-strontium-iron oxide (LSFO) bolometers
PublicationW artykule przedstawiono bolometr wykonany z tlenków lantanowo-strontowo-żelazowych zastosowany do detekcji promienowania podczerwonego. Parametry bolometru były badane za pomocą wzorcowego źródła poromieniowania o temperaturze 38°C (311 K) oddalonego od bolometru o 500 mm. W trakcie pomiarów uzyskano stosunek sygnał/szum wynoszący ok. 62 (tj. 35.9 dB). Na podstawie wyników pomiarów oszacowano dokładność pomiaru temperatury za...
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Numerical and experimental investigation of thermal convection near electric devices with vertical channels
PublicationThis 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
PublicationTo 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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Design analysis of ORC micro-turbines making use of thermal energy of oceans
PublicationThe 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...