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Search results for: LOW TEMPERATURE PROPERTIES
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublicationA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative...
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublicationA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems uti- lizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for...
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A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements
PublicationThe paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally...
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PROBLEMS OF THE STARTING AND OPERATING OF HYDRAULIC COMPONENTS AND SYSTEMS IN LOW AMBIENT TEMPERATURE (PART IV) MODELLING THE HEATING PROCESS AND DETERMINING THE SERVICEABILITY OF HYDRAULIC COMPONENTS DURING THE STARTING-UP IN LOW AMBIENT TEMPERATURE
PublicationDesigners of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to put such devices into operation appropriate investigations, including experimental...
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Local properties of organic coatings close to glass transition temperature
PublicationAcrylic coating applied on copper substrate has been investigated at different temperatures starting from the ambient one up to the level above the glass transition temperature. Its local topographic and electric properties have been examined with the atomic force microscopy (AFM) based approach including dc current mapping and local impedance spectroscopy. The local findings have been compared with the information from global...
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Spectroscopic and photophysical properties of ZNTPP in a room temperature ionic liquid
PublicationThe steady-state absorption and emission spectra and the time-resolved Soret- and Q-band excited fluorescence profiles of the model metalloporphyrin, ZnTPP, have been measured in a highly purified sample of the common room temperature ionic liquid, [bmim][PF(6)]. S(2)-S(0) emission resulting from Soret-band excitation behaves in a manner completely consistent with that of molecular solvents of the same polarizability. The ionic...
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The Influence of Synthesis Temperature on Manufacturing and Properties of SrSi2O2N2:Eu2+ Powders
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Effect of environmental temperature variations on protective properties of organic coatings
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Effect of environmental temperature variations on protective properties of organic coatings
PublicationW oparciu o model rozwoju naprężeń oraz niszczenia kumulatywnego przedyskutowano wpływ zmiennych temperatur środowiska na mechaniczną spójność i własności ochronne systemów powłokowych. Badano wpływ cykli temperaturowych pomiędzy 20 i 55 st. C oraz między -20 i 20 st. C na trwałość różnych powłokowych systemów malarskich na stali. Stosując technikę spektroskopii impedancyjnej monitorowano zmiany parametrów powłok poddanych cyklom...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublicationThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Modeling of low calorific gas burning in a deficient oxygen environment and high-temperature oxidizer
PublicationThe experimental research will be performed using the experimental facility with a combustion chamber. The oxygen concentration in combustion oxidizers will be varied from 21% by volume (normal) air to 2%. The test combustion chamber will be fed with propane or methane as the reference fuel, then with low calorific fuels as test gases obtained by mixing various combustible components, e.g. H2, CH4, CO, and neutral gases, e.g. N2,...
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Initial Stages of Angiosperm Greening Monitored by Low-Temperature Fluorescence Spectra and Fluorescence Lifetimes
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Low temperature removal of SO2 traces from air by MgO-loaded porous carbons
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Problems of the starting and operating of hydraulic components and systems in low ambient temperature (Part II)
PublicationPodczas rozruchu zespołów hydraulicznych w warunkach szoku termicznego dochodzi do dynamicznej zmiany wymiarów elementów tych zespołów. Odkształcenia elementów powodują zmianę efektywnego luzu między współpracującymi elementami. Na zmiany luzu ma pływ między innymi: różnica temperatur pomiędzy gorącym olejem a zimnym zespołem hydraulicznym, natężeniem przepływu czynnika roboczego, konstrukcji zespołu, rodzaju materiału i kształtu...
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Problems of the starting and operating of hydraulic components and systems in low ambient temperature (Part I)
PublicationW artykule przestawnie są problemy rozruchu i działania zespołów i układów hydraulicznych w niskich temperaturach otoczenia. Z tych powodów autor przebadał hydrauliczne zespoły i układy w warunkach szoku termicznego (oziębione zespoły zasilano gorącym czynnikiem roboczym). Określono parametry rozruchu w tych warunkach kilku zespołów oraz układów hydraulicznych, przy których ich eksploatacja jest bezpieczna. Badania eksperymentalne...
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Thermomechanical reclaiming of ground tire rubber via extrusion at low temperature: Efficiency and limits
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The effect of a low ambient temperature on the cold-start emissions and fuel consumption of passenger cars
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Combustion of low calorific fuel at room and high temperature and at different oxygen content in the oxidizer
PublicationPraca przedstawia wyniki badań spalania paliwa niskokalorycznego powstałego w wyniku gazyfikacji biomasy. Badania prowadzono w temperaturze pokojowej oraz w warunkach typowych dla technologii HiTAC, tj. w temperaturze powyżej samozapłonu paliwa i przy różnej zawartości tlenu w utleniaczu. Wykazano możliwość wykorzystania technologii HiTAC do spalania takich paliw.
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Microstructural evolution of 6061 aluminium alloy subjected to static and dynamic compression at low temperature
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In situ insight into the low-temperature promotion of ZIF-67 in electrocatalytic oxygen evolution reaction
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Low-temperature synthesis of zeolite from perlite waste — Part II: characteristics of the products
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Low temperature CVD growth of graphene nano-flakes directly on high K dielectrics
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Assessment of the Resistance Value of Trash Racks at a Small Hydropower Plant Operating at Low Temperature
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Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system
PublicationIt is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of...
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Thermo-mechanical reclaiming of ground tire rubber via extrusion at low temperature: Efficiency and limits
PublicationThermomechanical reclaiming of ground tire rubber (GTR) was performed at different temperatures (60, 120, and 180°C) using a co-rotating twin-screw extruder. Obtained samples were used in styrene-butadiene rubber (SBR) blends. As reference samples, SBR compounds containing untreated GTR were used. Curing characteristics, static and dynamic mechanical properties, and morphology of the obtained blends were determined. The results...
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The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2 Nanocomposites
PublicationSeries ofWO3/TiO2 nanocompositeswere obtained by hydrothermal method followed by calcination in the temperature range from 400∘C to 900∘C. The characteristics of photocatalysts by X-ray diffractometry (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) showed that increasing the calcination temperature from 400 to 900∘C resulted in change of photocatalytic activity under UV-Vis light.Moreover,...
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The Influence of Magnetron Sputtering Process Temperature on ZnO Thin-Film Properties
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The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge
Publication: Innovative low-temperature disintegration (process temperature 55 ◦C and oxygen concentration 0.2 mg/dm3 ) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublicationWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Dissolution of Nb-doped hydroxyapatite prepared via low-temperature mechanochemical method: Spectroscopy studies
PublicationCalcium phosphate glass ceramics with nominal hydroxyapatite stoichiometry doped with niobium were synthesized using simple as well as low-temperature mechanochemical method and then in the form of compressed pellet were submitted to the static dissolution process in distilled water for one month. The results of structural analysis, performed mainly on the base of spectroscopic methods such as: infrared absorption spectroscopy,...
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High temperature corrosion of steel equipment in modern rafinery environments with high and low sulphur content
PublicationPrzedstawiono charakterystykę i mechanizmy procesów wysokotemperaturowej korozji elementów ze stali we współczesnych rafineriach ropy naftowej podczas eksploatacji we frakcjach węglowodorowych o niskiej i wysokiej zawartości siarki. Zwrócono uwagę na procesy korozji siarkowej w obecności wodoru i bez obecności wodoru oraz proces pylenia metalu pod wpływem węgla ze środowiska - w wypadku niskiej zawartości siarki w środowisku.
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Experimental study of the fuel jet combustion in high temperature and low oxygen content exhaust gases
PublicationPrzeprowadzono badania eksperymentalne spalania pojedynczego strumienia paliwa gazowego. Paliwo podawano współosiowo do generowanych przez konwencjonalny palnik gazowy spalin o wysokiej temperaturze i niskiej zawartości tlenu. Badano wpływ zawartości tlenu w utleniaczu na widzialność płomienia i skład produktów spalania.
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The influence of temperature on properties of the polymer flexible joint used for strengthening historical masonries
PublicationA new method of repairing damaged structures by filling the cracks with a specially prepared elastomeric 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....
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Biochemical assays of intensified methane content in biogas from low-temperature processing of waste activated sludge
PublicationAnaerobic digestion (AD) is implemented as an important ‘waste to energy’ approach for converting organic-rich byproducts such as sewage sludge into biogas and nutrient-rich digestate. Sewage sludge consists of primary sludge and waste activated sludge (WAS), and low biodegradability of WAS limits methane production. This study presents the influence of the low-temperature pretreatment (LT-PT) of WAS on the efficiency of AD. Different...
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Influence of geometry and annealing temperature in argon atmosphere of TiO2 nanotubes on their electrochemical properties
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TiO2 photoactivity in vis and UV light: The influence of calcination temperature and surface properties
PublicationPrzygotowano serię fotokatalizatorów w postaci tlenku tytanu (IV) kalcynowanych w różnych temperaturach od 350 do 750˚C. Charakterystyka fotokatalizatorów za pomocą metod XRD, UV-Vis/DRS, FTIR, XPS, BET oraz BJH wykazała, że próbka TiO2 aktywna w świetle widzialnym posiadała strukturę anatazu, powierzchnię właściwą ok. 200 m2/g, absorbowała światło o długości fali λ>400 nm oraz zawierała 10,1 % at. węgla (wiązanie C-C). Aktywność...
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Influence of Firing Temperature on Phase Composition and Color Properties of Ceramic Tile Bodies
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The effect of elevated temperature on the properties of cement mortars containing nanosilica and heavyweight aggregates
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Mechanical Properties and Strength Reliability of Impregnated Wood after High Temperature Conditions
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Effect of brookite on the photocatalytic properties of mixed-phase TiO2 obtained at a higher temperature
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Influence of low-temperature physical hardening on stiffness and tensile strength of asphalt concrete and stone mastic asphalt
PublicationThis paper presents laboratory testing of stiffness modulus and indirect tensile strength of three asphalt concrete (AC) and three stone mastic asphalt (SMA) mixes after isothermal storage at temperature of -20oC, at different time intervals up to 16 days. The tests under repeated dynamic loading showed physical hardening of all tested mixes which was manifested by an evident increase of their stiffness moduli after isothermal...
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Analysis of the selection of low temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublicationThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Mechanical response of 6061-T6 aluminium alloy subjected to dynamic testing at low temperature: Experiment and modelling
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Low temperature growth of carbon nanotubes from methane catalytic decomposition over nickel supported on a zeolite
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Application possibilities of the low-temperature repairs on creep-resistance turbine components from material GX23CrMoV12-1
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Analysis of the selection of low-temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublicationThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Effects of La0.8Sr0.2MnO3 and Ag electrodes on bismuth-oxide-based low-temperature solid electrolyte oxygen generators
PublicationIn this study, La0.8Sr0.2MnO3 (LSM) was used as the ceramic electrode in a (Bi1.50Y0.50)0.98Zr0.04O3+δ (BYO)-based solid electrolyte oxygen generator (SEOG) and its performance was compared with that of a previously studied high-fire Ag electrode. Among La0.6Sr0.4Co0.2Fe0.8O3, LaNi0.6Fe0.4O3, Cu1.4Mn1.6O4, and LSM materials, only LSM materials did not trigger any chemical reaction or interdiffusion with BYO at temperatures up to...
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Investigating the combined impact of plasticizer and shear force on the efficiency of low temperature reclaiming of ground tire rubber (GTR)
PublicationIn the present work, ground tire rubber (GTR) was mechano-chemically reclaimed at ambient temperature using two-roll mills. Road bitumen and styrene-butadiene-styrene (SBS)-modified bitumen at variable content (in range: 2.5–20 phr) were applied as reactive plasticizers to enhance reclaiming of GTR. For better understanding the plasticizing effect of bitumen on the quality of obtained reclaimed rubber, mechano-chemically reclaimed...
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Effect of bitumen characteristics obtained according to EN and Superpave specifications on asphalt mixture performance in low-temperature laboratory tests
PublicationThe paper aims to identify those characteristics of bitumen which have the greatest impact on asphalt mixture low-temperature performance. It was observed that stiffness and m-value of bitumen from BBR test were moderately related to stiffness and m-value of asphalt mixture obtained from 3 PB test. Simultaneously those rheological properties significantly impact on cryogenic stresses induced during TSRST test. The multiple regression...
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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),...