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Search results for: NISKIE TEMPERATURY
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Effect of high pressure and sub-zero temperature on some gram-negative bacteria.
PublicationCelem pracy było określenie przeżywalności wybranych gramujemnych bakterii na działanie wysokiego ciśnienia i ujemnej temperatury. Traktowanie komórek bakterii ciśnieniem 193 MPa w temperaturze -20C przez 24 godziny, powodowało całkowitą inaktywację bakterii E. coli, P. fluorescens i T. thermophilus. Po działaniu ciśnienia przez krótszy czas występowały różnice we wrażliwości między badanymi szczepami. Najmniej odporny na działanie...
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Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
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Evaluation of Asphalt Mixture Low-Temperature Performance in Bending Beam Creep Test
PublicationLow-temperature cracking is one of the most common road pavement distress types in Poland. While bitumen performance can be evaluated in detail using bending beam rheometer (BBR) or dynamic shear rheometer (DSR) tests, none of the normalized test methods gives a comprehensive representation of low-temperature performance of the asphalt mixtures. This article presents the Bending Beam Creep test performed at temperatures from −20...
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The influence of the substrate temperature on the preparation of DNA films for studies under vacuum conditions
PublicationExperiments were carried out to determine the dependence of the physical form of supercoiled DNA films on the initial temperature of the substrate. Such films are often used in irradiation experiments involving low energy particles, like electrons or photons. In order to obtain absolute values for cross sections for such experiments, the spatial distribution of the sample in the film has to be well estimated. These investigations...
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Influence of cooling rate and additives on low-temperature properties of asphalt mixtures in the TSRST
PublicationThe paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 C/h, 3 C/h, 5 C/h and 10 C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each...
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Impact of high temperature drying process on beech wood containing tension wood
PublicationThe technology of high temperature drying has a great inuence on dimensional and selected physical changes in tension wood. Article is focused on the measurement properties such as moisture content, color changes and longitudinal warping. The quality of beech wood is determined based on structure and properties of wood, frequency of defects in wood material. The tension wood is considered as an important wood defect causing negative...
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
PublicationHot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point...
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The effect of high pressure and subzero temperature on gelation of washed cod and salmon meat
PublicationThe objective of the present work is to examine the infl uence of pressure up to 193 MPa at subzero temperature (without freezing of water) on myofi brillar proteins of salmon and cod meat and on the properties of gels obtained from washed mince of these fi sh. The solubility of proteins from myofi brils of cod and salmon meat suspended in 100 mM KCl solution increased aft er treating the samples with pressure above 60 MPa. The...
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Moisture content during and after high- and normal-temperature drying processes of wood
PublicationThe aim of the article is to present the results of moisture content of wood during and after the high-temperature steam and air–steam mixture drying processes and after an open air-drying process. The knowledge of moisture content changes of wood in the process of its drying is one of the important parameters to economy drying process and to keep the quality of dried wood. Wood samples, namely, spruce (Picea abies K.) and beech...
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Status report on high temperature fuel cells in Poland – Recent advances and achievements
PublicationThe paper presents recent advances in Poland in the field of high temperature fuel cells. The achievements in the materials development, manufacturing of advanced cells, new fabrication techniques, modified electrodes and electrolytes and applications are presented. The work of the Polish teams active in the field of solid oxide fuel cells (SOFC) and molten carbonate fuel cell (MCFC) is presented and discussed. The review is oriented...
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APPLICATION OF SATELLITE IMAGERY AND GIS TOOLS FOR LAND SURFACE TEMPERATURE ESTIMATION AND VERIFICATION
PublicationLand surface temperature (LST) plays an important role in many land-surface processes on regional as well on global scales. It is also a good indicator of energy flux phenomena and is used as a parameter in various Earth observation related studies. However, LST estimation based on processing and utilisation of satellite derived data constitutes several problems in terms of time limitations, accessibility, atmospheric influence...
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Determination of chlorine concentration using single temperature modulated semiconductor gas sensor
PublicationA periodic temperature modulation using sinusoidal heater voltage was applied to a commercial SnO2 semiconductor gas sensor. Resulting resistance response of the sensor was analyzed using a feature extraction method based on Fast Fourier Transformation (FFT). The amplitudes of the higher harmonics of the FFT from the dynamic nonlinear responses of measured gas were further utilized as an input for Artificial Neural...
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The Impact of Homogeneity of High Modulus Asphalt Concrete Layer on Low-Temperature Cracking
PublicationDuring winter season of 2012 numerous transverse cracks developed in high-modulus asphalt concrete (HMAC) base of newly constructed motorway. Pavement cracked both in transverse joint locations and in the area between them. Research which was conducted during investigation of the causes and mechanisms of cracking consisted of: field examination, laboratory testing of specimens cored out of the existing pavement, computational analyses...
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The influence of the substrate temperature on the preparation of DNA films for studies under vacuum conditions
PublicationPrzeanalizowano wpływ temperatury na formowanie warstw DNA. Sprawdzono wpływ stabilizatorów na jakość otrzymanych próbek. Stwierdzono, że optymalnymi warunkami przygotowywania filmów do badań w warunkach próżniowych jest - 10 st. C przy minimalnej zawartości NaOH.
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Dependence of the toxic components exhaust emission from the car engine starting temperature
PublicationW publikacji opisano wyniki badań empirycznych zależności stężeń toksycznych składników spalin od stanu cieplnego silnika w chwili rozruchu. Zwrócono uwagę na duże stężenia w pierwszych kilkudziesięciu sekundach po rozruchu. Badano silniki samochodów osobowych zarówno w eksploatacji jak i na hamowni podwoziowej.
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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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Management of low-temperature heat source by ORC aided by additional heat source
PublicationIn the paper presented is a concept to utilize waste heat from the power plant with the aid of the low-temperature ORC cycle. The ORC system is heated from two heat sources, the first one being the flow rate of waste heat obtained from the exhaust gases. Subsequently, the working fluid in the cycle is additionally heated by the condensing steam from the low pressure turbine extraction points increasing in such way the level of...
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INFLUENCE OF TEMPERATURE ON THE ACTIVITY OF ANAMMOX GRANULAR BIOMASS - SHORT AND LONG-TERM ASPECT
PublicationThe aim of this study was to determine a short-term and long-term effect of temperature on the anammox process rate and determination of temperature coefficients in the Arrhenius and Ratkowski equations. The short-term effects of temperature on the anammox biomass were investigated in batch tests at ten different temperatures in the range of 10-55 ̊C. The maximum rate 1.3 gN (gVSS·d)-1 observed at 40 ̊C. The minimum rate, close...
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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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Management of low-temperature heat source by ORC aided by additional heat source
PublicationThe presented work is aimed at utilisation of waste heat in the manner to produce electricity in ORC installation. Therefore the precondition of the study was to use the waste heat available in the form of a stream of hot water at 90°C. Such low enthalpy heat source is rather insufficient to produce a good quality vapour to feed the ORC turbine. That was the incentive to search for the ways of increasing the temperature of the...
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GPU based implementation of Temperature-Vegetation Dryness Index for AVHRR3 Satellite Data
PublicationPaper presents an implementation of TVDI (Temperature-Vegetation-Dryness Index) algorithm on GPU (Graphics Processing Unit). Calculation of this index is based on LST (Land Surface Temperature) and NDVI (Normalized Difference Vegetation Index). Discussed results are based on multi-spectral imagery retrieved from AVHRR3 sensors for area of Poland. All phases of TVDI implementation on GPU are modified in respect to CUDA platform....
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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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Pre-oxidation of porous ferritic Fe22Cr alloys for lifespan extension at high-temperature
PublicationPre-oxidation of porous ferritic Fe22Cr alloys was extensively studied in this paper. Weight gain measurements and SEM analysis revealed that pre-oxidation performed at 900◦C for 40 min increased the lifespan of the alloy. A Cr evaporation study did not disclose any significant influence of the pre-oxidation process on the Cr content in the alloy. For a more detailed assessment, TEM imaging and X-ray tomography measurements of...
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Study of Soil Temperature and Moisture Changes in a Physical Model of an Underground Cable Line
PublicationThe ampacity of power cables is highly dependent on the thermal resistivity of the soil in which they are laid. The lower it is, the higher this ampacity. The thermal resistivity of the soil decreases as its moisture increases. Therefore, it is preferable that the soil around the cables has high moisture. Unfortunately, the heat generated in heavily loaded cables causes the migration of moisture from the surrounding soil, which...
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Numerical simulation of temperature distribution of heat flow on reservoir tanks connected in a series
PublicationThe flow of temperature distribution through a medium in thermodynamic studies plays an important role in understanding physical phenomena in chemical science and petroleum engineering, while temperature distribution indicates the degree of reaction that must be undergone to obtain the final product. Therefore, this paper aims to present and apply the exponential matrix algorithm (EMA), differential transformation algorithm (DTA),...
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Impact of Temperature and Nanoparticle Concentration on Turbulent Forced Convective Heat Transfer of Nanofluids
PublicationTheoretical analysis of the influence of nanoparticles and temperature on the average Nusselt (Nu) number and the average heat transfer coefficient (HTC) during the turbulent flow of nanofluid in a horizontal, round tube was carried out. The Nu number is a function of the Reynolds (Re) number and the Prandtl (Pr) number, which in turn are functions of the thermophysical properties of the liquid and the flow conditions. On the other...
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Impact of temperature on optical sensing in biology based on investigation of SARS‐CoV ‐2
PublicationIn this paper, we present an investigation of the influence of the temperature on the sensing of biological samples. We used biofunctionalized microsphere-based fiber-optic sensor to detect immunoglobulin G attached to the sensor head at temperatures relevant in biological research: 5°C, 25°C, and 55°C. The construction of the sensor allowed us to perform measurements in the small amount of solution. The results of our experiment...
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Influence of Operation Conditions on Temperature Hazard of Lithium-Iron-Phosphate (LiFePO4) Cells
PublicationThe article presents and discusses the results of research on hazard, especially temperature, for selected lithium-ion-phosphate cells operated in accordance with the manufacturer’s recommendations but used under onerous mining conditions. This applies to the performance of cells in battery sets without the application of any management system (BMS). On the basis of the obtained test results, first of all, the influence of the...
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Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublicationConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
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Field Evaluation of High Modulus Asphalt Concrete Resistance to Low-Temperature Cracking
PublicationHigh-modulus asphalt concrete has numerous advantages in comparison to conventional asphalt concrete, including increased resistance to permanent deformations and increased pavement fatigue life. However, previous studies have shown that the construction of road pavements with High Modulus Asphalt Concrete (HMAC) may significantly increase the risk of low-temperature cracking. Those observations were the motivation for the research...
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Effect of temperature change on refractive index of an egg white and yolk: a preliminary study
PublicationIn this article, the refractive index of an egg white and yolk depending on temperature in range 30 - 47 °C over 1550 nm was determined. The measurement head was constructed as fiber optic Fabry-Perot interferometer with interference between polished fiber end-face and aluminum weighing dish. The measurement setup has been made of an optical spectrum analyzer, a superluminescent diode with a central wevelength of 1550 nm, 2:1 fiber...
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The influence of inflation pressure and ambient temperature on the value of the truck tires rolling resistance
PublicationThe articlediscusses the effect of inflation pressure and the ambient temperature on the value of the rolling resistance of truck tires which directly translates into fuel consumption. For this purpose, a series of measurements was made at two ambient temperatures (at 25°C and -15°C), using different pumping pressures.
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Influence of yttria surface modification on high temperature corrosion of porous Ni22Cr alloy
PublicationProtective coatings for porous alloys for high temperature use are relatively new materials. Their main drawback is high temperature corrosion. In this work protective coatings based the on Y-precursor infiltrated into the sintered Ni22Cr alloys are studied at 700°C. Effects of the amount of the protective phase on the resulting corrosion properties are evaluated in air and humidified hydrogen. Weight gain of the samples, their...
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FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
PublicationThe paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding...
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Temperature-controlled nanomosaics of AuCu bimetallic structure towards smart light management
PublicationGold–copper nanostructures are promising in solar-driven processes because of their optical, photocatalytic and photoelectrochemical properties, especially those which result from the synergy between the two metals. Increasing interest in their internal structure, such as the composition or distribution of the Au and Cu as well as the size and shape of the nanoparticles, have developed to define their physicochemical properties. In...
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Optical fibre temperature sensor based on fluorescein and rhodamine codoped polymer layer
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Effect of Temperature on Upconversion Luminescence in Yb3+/Tb3+Co-Doped Germanate Glass
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Badanie degradacji powłok organicznych metodą EIS w warunkach podwyższonych temperatur
PublicationPomimo nieustannego rozwoju zaawansowanych technik antykorozyjnych oraz imponująco wysokiej odporności współczesnych warstw i pokryć ochronnych problem zabezpieczenia powierzchni metalicznych jak i niemetalicznych jest nadal aktualny. Wciąż rosnące zapotrzebowanie na nowe metody ochrony antykorozyjnej oraz dążenie do jak najmniejszej degradacji środowiska naturalnego wytyczają współczesne trendy rozwoju przemysłu antykorozyjnego....
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Badania teoretyczne i doświadczalne rozkładu temperatur w hydrodynamicznym łożysku wzdłużnym
PublicationW referacie zaprezentowano przykładowe wyniki obliczeń uzyskane z wykorzystaniem rozwijanej w Politechnice Gdańskiej nowej metody oceny własności hydrodynamicznych łożysk wzdłużnych. Bazuje ona na wykorzystaniu techniki automatycznej wymiany informacji pomiędzy uwzględnianymi w analizach problemów obliczeń łożyskowych obszarami zadania tj. płynowym i strukturalnym, wykorzystując w tym celu dostępne programy obliczeniowe MES (technika...
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Badanie eksperymentalne pompy wielotłoczkowej osiowej PWK 27 firmy Hydrotor w niskich temperaturach otoczenia
PublicationW artykule przedstawiono stanowisko oraz badania pompy wielotłoczkowej osiowej PWK 27 w niskich temperaturach otoczenia. Celem badań pompy PWK27 było określenie obszaru parametrów prawidłowego rozruchu w warunkach szoku termicznego oraz analiza zjawisk występujących podczas rozruchu pomp wielotłoczkowych osiowych.
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Badania cech reologicznych mieszanek mineralno-asfaltowych podczas pełzania przy zginaniu w niskich temperaturach.
PublicationReferat przedstawia metodykę oraz wyniki badań cech reologicznych mieszanek mineralno-asfaltowych w zakresie temperatur od -10 st C do +20 st C. W badaniach wykorzystano metodę zginania belek obciążonych stałą siłą skupioną przyłożoną w środku rozpiętości belki. Zastosowano dwa typy mieszanek mineralno-asfaltowych: beton asfaltowy z asfaltem zwykłym i mastyks grysowy SMA z asfaltem modyfikowanym. Do wyznaczenia cech reologicznych...
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Wykorzystanie teorii zbiorów rozmytych do wyznaczania dostaw gazu ziemnego z sieci niskiego ciśnienia
PublicationOpisano koncepcję wykorzystania teorii zbiorów rozmytych do szacowania ilości gazu dostarczonego odbiorcom połączonym do sieci niskiego ciśnienia. Cechy systemów dystrybucyjnych gazu powodują, że nie jest możliwe pozyskanie pełnej informacji o ilościach odebranych przez tych odbiorców. Zaproponowany sterownik rozmyty umożliwia na pozyskanie dokładniejszych danych o wartościach rocznych dostaw i w związku z tym może być przydatnym...
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Analiza przyczyn pożaru w pomieszczeniu rozdzielni niskiego napięcia w Parku Technologicznym w Gdyni
PublicationW ekspertyzie analizowano przyczyny, przebieg i skutki zwarcia trójfazowego w rozdzielnicy niskiego napięcia.
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Wpływ grubości kryzy cylindrycznej na stabilność współczynnika przepływu przy niskich wartościach liczby Reynoldsa
PublicationW pracy przedstawiono wyniki badań eksperymentalnych i numerycznych dla kryzy cylindrycznej o przewężeniu β = 0,5 przy przepływającej wodzie w kanale DN50. Analizie poddano trzy kryzy cylindryczne dla wybranych wartości stosunku długości (grubości) otworu przepływowego do jego średnicy L/d (0,5; 1,0 i 2,0). Eksperymenty przeprowadzono w zakresie zmiany liczb Reynoldsa 1800 < Re < 17000, a symulacje numeryczne dla wybranego punktu...
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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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Ocena własności mechanicznych lekkich pian poliuretanowych w świetle ich zastosowania do budowy barek rzecznych w niskim zanurzeniu. Część II: Badania.
PublicationBadano pianę poliuretanową o gęstości około 53 ÷ 62 kg/m3. Wykonano niskocyklowe badania zmęczeniowe przy częstotliwości 0,1 Hz, które wykazały szybki wzrost deformacji piany poliuretanowej przy cyklicznych naprężeniach ściskających i ścinających przekraczających około 60% wytrzymałości doraźnej.
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Reclaiming ground tire rubber at low temperatures: benefits and limitations
PublicationLower extrusion temperatures during rubber reclamation lead to a reduction in toxic degradation products and improve the mechanical properties of vulcanizates, at the expense of reduced processability.
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Jednosekwencyjny statyczny model prądowo-napięciowo-temperaturowy tranzystora MOS.
PublicationZaprezentowano i zweryfikowano eksperymentalnie nowy jednosekcyjny statyczny model pradowo-napięciowo-temperaturowy tranzystora MOS. Nowy model jest spójny fizycznie i zawiera dużo mniej parametrów niż powszechnie znane modele.
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Determination of ability of hydrotronic systems to start in low ambient temperatures
PublicationPrzedstawiono wyniki badań symulacji komputerowej zespołów układów hydrotronicznych w warunkach szoku termicznego. Pokazano metodę określania zdatności hydrotronicznych zespołów i układów podczas rozruchu w warunkach szoku termicznego.
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Influence of design of hydraulic components on their operation in low ambient temperatures
PublicationW artykule przestawiono wpływ konstrukcji zespołów hydraulicznych na ich działanie w niskich temperaturach otoczenia.