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Search results for: temperatury ujemne
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The wear of PVD coated elements in oscillation motion at high temperature
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Mitigation of Membrane Wetting by Applying a Low Temperature Membrane Distillation
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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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The effect of temperature on the power drop in crystalline silicon solar cells
PublicationPrzedstawiono wpływ temperatury i długości fali zaabsorbowanego promieniowania na parametry elektryczne krzemowych ogniw i modułów fotowoltaicznych. Zaobserwowano spadek mocy wyjściowej (-0.65%/K), współczynnika wypełnienia charakterystyki FF (-0.2%/K) i sprawności konwersji (-0.08%/K) ze wzrostem temperatury. Zaprezentowano również charakterystykę spektralną napięcia otwartego obwodu dla ogniw krzemowych.
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Cold Start Emissions Investigation at Different Ambient Temperature Conditions
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Low-temperature reactivity of the surface species of vanadia–tungsta catalyst
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Lower Temperature Dehydrogenation of Methylcyclohexane by Membrane-assisted Equilibrium Shift
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Low-temperature processing of thin-film electrolyte for electrochemical devices.
PublicationPrzygowanie filmów elektrolitu jest jednym z najbardziej istotnych procesów technologicznych wytworzenia urządzeń elektrochemicznych takich jak ogniwa paliwowe. Zmniejszenie grubości filmu jest powiązane ze zmniejszeniem rezystancji elektrolitu, co bardzo korzystnie wpływa na wydajność ogniw paliwowych. W pracy tej przedstawiono niskotemperaturową (<1000C) metodę wytwarzenia filmów elektrolitu z tlenku cyrkonu stabilizowanego itrem...
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Central heating temperature control algorithm for systems with condensing boilers
PublicationThe problem of control of a central heating system in a small residence is considered. It is assumed that the system is based on a condensing boiler. Since the boiler efficiency depends on a returning water temperature, the proposed control goal is to provide proper air temperature in the residence as well as the lowest possible water temperature. The proposed algorithm is applied to two buildings. Both of them have the same heating...
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Comparison of elastic and viscoelastic analysis of asphalt pavement at high temperature
PublicationThere are many various rheological models which are used for modeling of asphalt layers in flexible pavement structures. It can be expected that the use of various models may affect different results of mechanical pavement calculations and analysis. The paper presents comparison of the use of Burgers’ and Huet-Sayegh’s viscoelastic models and Hooke’s elastic model to calculate pavement deflections and strains at the bottom of asphalt...
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Temperature influences on shear stability of a nanosize plate with piezoelectricity effect
PublicationPurpose The purpose of this paper is to predict the mechanical behavior of a piezoelectric nanoplate under shear stability by taking electric voltage into account in thermal environment. Design/methodology/approach Simplified first-order shear deformation theory has been used as a displacement field. Modified couple stress theory has been applied for considering small-size effects. An analytical solution has been taken into account...
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Assessment of the Accuracy of a Virtual Multi-Channel Temperature Measuring Instrument
PublicationThe multi-channel temperature measurement system developed works with NTC thermistors. The article presents the results of theoretical and empirical evaluation of accuracy obtained in measurement channels. The basis for the theoretical assessment is the mathematical model for each of the measurement channels and the characteristics of the system elements included in the circuits of the measurement channel. Two different methods were...
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High temperature corrosion of evaporator tubes with thermal sprayed coatings
PublicationDegradation examinations of outer surface of low-emission steam boiler evaporator tubes are presented in the paper. Metallographic evaluation of scale morphology, its micro sites chemical composition analysis and distribution of elements on cross sections have been performed. Water-wall tubes were exposed in steam boiler for up to two years period. Common tubes made of 16Mo3 steel suffered sulphide and molten salts corrosions....
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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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Temperature influence on tire/road noise evaluated by the drum method
PublicationAmbient air and road surface temperatures substantially affect the road vehicle noise emission. The temperature influence on tire/road noise depends mainly on tire-road combination. It is different for dense and porous pavements, for bituminous and cement ones. It differs also depending on tires. The correction procedures for temperature effect are still under consideration and preparation. Laboratory experiment was prepared to...
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Proton Conducting Ceramic Powder Synthesis by a Low Temperature Method
PublicationMolten salt synthesis (MSS) is a simple method for the preparation of ceramic powders with specific morphology. The main role of the molten salts is to increase the reaction rate and lower the reaction temperature. It occurs because of much higher mobility of reactants in the liquid medium than in the solid state. In this work the molten salt synthesis was applied to produce ceramic powders of La0995Ca0005NbO4 and BaCe09−xZrxY01O3....
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Fiber-optic temperature sensor using low-coherence interferometry
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The influence of the temperature treatment on the Nd2-xCexCuO4-y crystals surface
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IMPEDANCE MEASUREMENT MODULE FOR GAS SENSORS WITH TEMPERATURE CONDITIONING FEATURE
PublicationThe paper presents an impedance measurement module which is aimed for gas sensor. Sensor’s heater temperature conditioning and modulation feature is available in order to allow implementation of different techniques improving selectivity and sensitivity of gas sensors. The measurement module uses three-parameter sine-fitting technique for impedance measurement. To monitor sensor temperature, the resistance of the sensor’s heater...
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Analysis of unsteady flow forces on the thermowell of steam temperature sensor
PublicationIn this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically...
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Molecular Strategy for Survival at a Critical High Temperature in Eschierichia coli
PublicationThe molecular mechanism supporting survival at a critical high temperature (CHT) in Escherichia coli was investigated. Genome-wide screening with a single-gene knockout library provided a list of genes indispensable for growth at 47°C, called thermotolerant genes. Genes for which expression was affected by exposure to CHT were identified by DNA chip analysis. Unexpectedly, the former contents did not overlap with the latter except...
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Analysis of diagnostic informativeness of the exhaust temperature of a naval gas turbine
PublicationThe conducted investigations aimed to carry out an analysis of the possibility that the failures identification in the automatic control system of a gas turbine engine could be worked out on the basis of measurements of the exhaust stream temperature behind the gas generator. The exhaust temperature represents a basic control parameter, enabling technical state evaluation of the engine within the operation process, which is observed...
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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 Abrasive Machine on Temperature During One Side Lapping
PublicationPrzedstawiono wyniki badań temperatury układu wykonawczego docierarki jednotarczowej. Analizowano temperaturę trzech pierścieni prowadzących separatory przy wykorzystaniu kamery termograficznej V-20 II firmy VIGO System S.A.
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Coatings for improvement of high temperature corrosion resistance of porous alloys
PublicationPorowate stopy metaliczne są potencjalnymi podłożami nośnymi dla tlenkowych ogniw paliwo. Ich stosowanie obniża cenę ogniw paliwowych, co zaowocuje ich szybszą komercjalizacą. Jednak są one podatne na korozję w wysokich temperaturach. Dotychczas brak jest metod, które mogą poprawić rezystancję korozyjną porotawych stopów w wysokich temperaturach porowatych stopy do zastosowań SOFC. W tym artykule zaproponowano sposób na poprawę...
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Changes in bacterial cells induced by high pressure at subzero temperature
PublicationW publikacji przedstawiono wyniki badań dotyczące zmian jakie zachodzą w komórkach bakterii Escherichia coli po działaniu wysokiego ciśnienia w ujemnej temperaturze. Stwierdzono, że w wyniku działania ciśnienia 193 MPa zachodzącą zmiany w błonie cytoplazmatycznej i ścianie komórkowej bakterii. W tych warunkach następowała prawie całkowita utrata wewnątrzkomórkowego ATP z komórek badanych szczepów znajdujących się w fazie logarytmicznej....
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High temperature corrosion and corrosion protection of porous Ni22Cr alloys
PublicationIn this work corrosion kinetics of the porous IN625 alloy is studied in the temperature range of 700 °C – 800 °C in air and humidified hydrogen for up to 1000 hours. Moreover, an effective and simple method of reducing corrosion rates of porous alloys by the infiltration of the rare earths elements is shown. Modification by the yttrium containing precursor reduces the corrosion rate by a factor of 50 in air at 700 °C so that the...
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EXHAUST TEMPERATURE MEASUREMENTS OF THE MARINE TURBOCHARGED DIESEL ENGINES IN OPERATION
PublicationThe article presents the selected metrology issues concerning the exhaust temperature of the turbocharged marine engines during operation. The special concern has been paid on existing disturbances as well as thermodynamical interpretation of the recorded measurement signal. A diagnostic informativeness of the standard exhaust temperature’s measurements has worked out while the engine runs in steady states has been also considered...
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Methodology of estimating temperature measurement uncertainty in a system for endurance tests.
PublicationThe team consisting of the article authors developed a non-invasive method and a system for measuring temperature during an endurance test. A thermocouple which provided the required accuracy of changes in temperature dynamics measurements was used for the purpose of the required research. The paper presents the methodology for estimating uncertainty of temperature measurement done with the presented system, using a method based...
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Hyaluronan-Chondroitin Sulfate Anomalous Crosslinking Due to Temperature Changes
PublicationGlycosaminoglycans are a wide class of biopolymers showing great lubricating properties due to their structure and high affinity to water. Two of them, hyaluronic acid and chondroitin sulfate, play an important role in articular cartilage lubrication. In this work, we present results of the all-atom molecular dynamics simulations of both molecules placed in water-based solution. To mimic changes of the physiological conditions,...
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Wavelet Transform Analysis of Temperature Modulated Gas Sensor Response
PublicationThe aim of the study was to evaluate whether it is possible to extract the information about the gas concentration despite the influence of humidity. Commercial semiconductor sensor response was examined under the application of a periodic temperature change. The data was collected using measurement protocol for different concentrations of ammonia at specified levels of relative humidity. In this work we focused on the evaluation...
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Temperature-dependent structure-property modeling of viscosity for ionic liquids
PublicationIn this paper we present the methodology for assessing the ionic liquids' viscosity at six temperature points (25, 35, 45, 50, 60 and 70 [C]), which utilizes only the in silico approach. The main idea of such assessment is based on the "correction equation" describing the correlation between experimentally measured viscosity and theoretically derived density (calculated with use of molecular mechanics), given at 6 different temperature...
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Photovoltaic module temperature stabilization with the use of phase change materials
PublicationThe worldwide growth of photovoltaics (PVs) has formed an exponential curve for more than four decades. During this period of time, PVs have evolved from a pure niche market of small-scale applications towards becoming a mainstream electricity source. The influence of temperature on the electrical parameters of crystalline silicon solar cells and solar modules is well described in the literature. In order to diminish these effects,...
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Investigation of the temperature modulation parameters on semiconductor gas sensor response
PublicationIn this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor...
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ZnO ALD-Coated Microsphere-Based Sensors for Temperature Measurements
PublicationIn this paper, the application of a microsphere-based fiber-optic sensor with a 200 nm zinc oxide (ZnO) coating, deposited by the Atomic Layer Deposition (ALD) method, for temperature measurements between 100 and 300°C, is presented. The main advantage of integrating a fiber-optic microsphere with a sensing device is the possibility of monitoring the integrity of the sensor head in real-time, which allows for higher accuracy during...
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Numerical analysis of high temperature minichannels heat exchanger performance
PublicationNowadays, the most difficult technological challenge in energy sector is connected with the gas micro-CHP units, dedicated to the distributed power generation. They are expected to be of high efficiency and at the same time of compact in size. Regarding the first reason, significant increase in microturbine efficiency can only be achieved by increase in the engine operating temperature. Therefore, one of the critical elements in...
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CaO-based high temperature CO2 sorbents – Literature review
PublicationThe use of CaO-based adsorbents has a high potential to capture CO2 from various systems due to its high reactivity with CO2, high capacity, and low cost of naturally derived CaO. The application of CaO-based sorbents to remove carbon dioxide is based on a reversible reaction between CaO and CO2. However, multiple carbonation/calcination cycles lead to a rapid reduction in the sorption capacity of natural CaO, and therefore efforts...
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Performance of acicular grindable thermocouples for temperature measurements at sliding contacts
PublicationThe present study investigates the performance of acicular grindable thermocouples based on a constantan wire / steel hollow cylinder construction. The experiments showed that the measuring junction electrical resistance, temperature–voltage characteristic, measuring junction rise time and signal noise standard deviation of the acicular thermocouples are comparable to those of conventional J-type thermocouples with bare wire diameter...
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On the differential effect of temperature on the Nusselt-Rayleigh relationship in free convection
PublicationThe aim of and inspiration behind this paper was to explain the reasons, also observed by other researchers, of the discrepancy in the results of experimental free convection, which for small Rayleigh and Nusselt numbers in the initial phase of research can sometimes reach several hundred percent. These discrepancies decrease with increasing heating power and plate surface temperature, in proportion to the increase in Ra and Nu,...
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Multi-Channel Virtual Instrument for Measuring Temperature—A Case Study
PublicationThe article presents the hardware and software configuration of the developed multi-channel temperature measurement system as well as calibration procedures and measurement results verifying the properties of measurement channels. The system has been developed and dedicated primarily for measuring the temperature distribution in a laboratory model simulating underground power lines. With the adopted configuration of the analog...
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Electrochemical capacitor temperature fluctuations during charging/discharging processes
PublicationThepaperpresentsaproposalofusingadditionalstatisticalparameterssuchas:standarddeviation,variance, maximum and minimum increases of the observed value that were determined during measurements of temperature fields created on the surface of the tested electrochemical capacitor. The measurements were carriedoutusingthermographicmethodsinordertosupportassessmentoftheconditionofelectrochemical capacitorunderclassicdurabilitytestsbasedonmethodsofdeterminationofcapacityandequivalentseries...
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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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Circumferential temperature distribution during nucleate pool boiling outside smooth and modified horizontal tubes
PublicationPrzedstawiono wyniki badań eksperymentalnych obwodowego rozkłądu temperatury w poziomych rurkach, ogrzewanych elektrycznie na których zachodzi wrzenie pęcherzykowe. Wykazano, że lokalne - w obszarze górnej tworzącej rurki, zastosowanie powłki porowatej prowadzi do wygładzenia rozkładu temperatury oraz obniżenia średniej temperatury ścianki.
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Strengthening of thin-walled columns against flexuralbuckling at elevated temperatur.
PublicationZa pomocą analizy wrażliwości wyznaczono mmiejsca wzmocnienia słupa stalowego obciążonego działaniem wysokiej temperatury. Wyznaczono przybliżoną wartość siły krytycznej słupa przy zmiennej temperaturze. Zastosowano model stali zgodny z polską normą PN-90/B-03200.
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Sum of Effective Temperatures in Colorado Beetle Control
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Właściwości mechaniczne i struktura betonów konopnych w warunkach oddziaływania wysokiej temperatury
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ROZKŁAD TEMPERATURY W WIELOSKŁADNIKOWYM WIELOWARSTWOWYM KOMPOZYCIE Z POPRZECZNĄ GRADACJĄ WŁAŚCIWOŚCI EFEKTYWNYCH
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ANALIZA ROZKŁADU TEMPERATURY W ŚCIANIE ŻELBETOWEGO ZBIORNIKA, UWZGLĘDNIAJĄCA DWUWYMIAROWY PRZEPŁYW CIEPŁA
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Obwodowy rozkład temperatury przy wrzeniu wody na rurkach ze zmodyfikowaną powierzchnią
PublicationPrzedstawiono wyniki badań eksperymentalnych przejmowania ciepła podczas wrzenia w dużej objętości na poziomych rurkach ogrzewanych elektrycznie. Badania przeprowadzono dla małych gęstości strumienia ciepła, a czynnikiem roboczym była woda destylowana w stanie nasycenia. Fragment powierzchni grzejnej badanych rurek został zmodyfikowany przez naniesienie metalicznej warstwy porowatej.
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Analiza modelu matematycznego opisującego wzrost temperatury podczas docierania jednostronnego powierzchni płaskich
PublicationPrzedstawiono weryfikację modelu matematycznego opisującego temperaturę elementów układu wykonawczego docierarki jednotarczowej od podstawowych warunków procesu docierania. Analizowano obróbkę na docierarce Abralap 380, określając wpływ nacisku jednostkowego, prędkości i czasu docierania elementów stalowych mikroziarnami węglika krzemu o numerze F600/9. W badaniach wykorzystano kamerę termograficzną z serii V-20 II firmy Vigo System...