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Search results for: PASSIVE EARTH PRESSURE
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Influence of Properties of Hydraulic Fluid on Pressure Peaks in Axial Piston Pumps’ Chambers
PublicationThe article concentrates on the research of the pressure peaks in a working chamber of an axial piston pump. The main focus of the article is the influence of fluid properties on the pressure peaks value. Experimental and analytical methods were used to determine the impact of the fluid density, viscosity, compressibility and aeration. The article describes the pressure peak generation process and explains the theoretical basis...
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Transient States during Short-circuit in a Line Powered by UPS and its Impact on Earth Fault Loop Impedance Measurement and Power Quality
PublicationThe short-circuit in a line powered by Uninterruptible Power Supply (UPS) during different UPS operation modes is presented in the article. The transient state condition related to the short-circuit in a line fed from double conversion On-line UPS is discussed in detail. The results of the measurements of earth fault loop impedance (FLI) in circuits powered by UPS with the instruments of various manufacturers are presented. The...
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Comparison between measured and calculated underwater pressure of merchant ship
PublicationFrom 2012 The Polish Naval Academy take part in an international research project SIRAMIS, carried out in the framework of the European Defence Agency. The objective of this project is to improve the understanding of ship signature interaction with multi influence sensors in relevant and realistic scenario's. This paper describes selected results of the comparison results of sea trials and model calculations of the hydrodynamic...
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Analysis of hydrodynamic pressure fields of motorboats and pontoons in shallow water
PublicationThe article presents the results of calculations of the pressure fields generated by a motorboat at the bottom of a shallow sea. Calculations were made using the boundary elements method (BEM), arranged on the surface of the boat and the bottom of the sea. This method is described in [3], and applied on a free surface linearized boundary condition. Results for four different lengths of motorboats, from 2.85 m to 9.5 m, sea depth...
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Highly Reliable Passive RFID-Based Inductor–Capacitor Sensory System Strengthened by Solvatochromism for Fast and Wide-Range Lactate Detection
PublicationA passive radio frequency-identification-based inductor-capacitor (LC) lactate sensory system with a specific dye-containing interdigitated capacitor (IDC) in which the sensing signal is amplified by the solvatochromic effect is proposed. When a lactate solution contacts the IDC of the LC lactate sensor, the capacitance of the IDC changes, changing the resonance frequency of the sensor. This changes the oscillation frequency of...
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OSL and RL of LiMgPO4 crystals doped with rare earth elements
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Antiferromagnetic Order in the Rare-Earth Halide Perovskites CsEuBr3 and CsEuCl3
PublicationBulk CsEuBr3 and CsEuCl3 are experimentally shown to be magnetic semiconductors that order antiferromagnetically at Néel temperatures of 2.0 K and 1.0 K, respectively. Given that nanoparticles and thin films of CsEuCl3 have been reported to order ferromagnetically at a similar temperature, our observation of antiferromagnetic ordering in CsEuBr3 and CsEuCl3 expands the possible applications of halide perovskites to now include...
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Expedited Re-Design of Multi-Band Passive Microwave Circuits Using Orthogonal Scaling Directions and Gradient-Based Tuning
PublicationGeometry scaling of microwave circuits is an essential but challenging task. In particular, the employment of a given passive structure in a different application area often requires re-adjustment of the operating frequencies/bands while maintaining top performance. Achieving this necessitates utilization of numerical optimization methods. Nonetheless, if the intended frequencies are distant from the ones at the starting point,...
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Architectural and Urban Planning Solutions for the Protection of Heritage Buildings in the Context of Terrorist Attacks: Following the Example of Passive Protection Systems
PublicationEvents in recent years showing numerous terrorist attacks raise awareness regarding the neces-sity of considering the safety of heritage buildings. The analysis of available data allows us to conclude that it is not possible to fully prevent terrorist attacks. On the other hand, it is possible to minimize the impact of such incidents through proper design of Passive Protection System (PPS) components. One possible architectural...
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Estimation of wind pressure acting on the new palm house in Gdansk
PublicationThis paper deals with the problem of numerical simulations of wind loads acting on a Palm House with complex geometry. Flow simulations with aid of computational fluid dynamics procedures have been performed to check if the pressure distributions for the structure are greater than those calculated using the standard design codes with assumption that the Palm House horizontal cross sections are described by smooth cylinders.
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Using differential pressure sensor to measure nitrous oxide level in a tank
PublicationA method for measuring the level of liquid nitrous oxide oxidizer in a hybrid rocket motor oxidizer tank is proposed. Presented approach is more accurate than the most commonly used method of this measurement, which employs weighting of the whole sounding rocket or an oxidizer tank. In our solution we use a differential pressure sensor to measure the change of pressure at the bottom of an oxidizer tank in comparison to the pressure...
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Pressure drop related to flow maldistribution in a model minichannel plate heat exchanger
PublicationThe paper describes the issues related to the pressure drop that accompanies the phenomenon of maldistribution of working fluid between the channels of a model minichannel plate heat exchanger. The research concerns a single exchanger's plate containing 51 (in every geometry) parallel rectangular minichannels of hydraulic diameters 461 µm, 571 µm, 750 µm and 823 µm. In addition, the more complex geometry has been investigated,...
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Modelling of heat transfer in supercritical pressure recuperators
PublicationIn the paper presented is analysis of convective flow heat transfer at supercritical pressure in channels of heat exchanger working in the thermodynamic cycle. The modelling is based on the division of the flow into three regions, namely the heavy fluid, a two phase flow consisting of the heavy and light fluids and finally the light fluid flow. Modelling is concentrated on the region of simultaneous flow of two fluids divided into...
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Influence of operating pressure on the durability of a satellite hydraulic motor supplied by rapeseed oil
PublicationThis article describes the results of a durability test of a hydraulic satellite motor supplied by rapeseed oil. The tests were carried out on a test stand in a power recuperation system. The tests of the motor were carried out at a constant shaft speed for three fixed pressure drops in the motor. This made it possible to demonstrate the influence of the motor operating pressure on the durability of the satellite mechanism. The...
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Developing assumptions for the tram noise attenuation passive system using the noise maps analysis method
PublicationThe paper presents experimental research carried out to determine the possible actions to reduce thenoise generated by trams in a highly urbanised area. A few design strategies affecting tram ride qualityhave been presented – especially in the aspect of the acoustic phenomena. Main sources of the noisein trams were characterised. The paper includes selected results of comprehensive...
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Bistatic passive radar simulator with spatial filtering subsystem
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Roll respose of ship fitted with passive stabilizing tank.
PublicationPrzedstawiono fizyczny i matematyczny model kołysań statku z biernym zbiornikiem stabilizacyjnym. Wyprowadzono równania ruchu i podano ich rozwiązania. Określono najistotniejsze zalecenia projektowe w oparciu o uzyskane rozwiązania. Wskazano kierunek poszukiwania optymalnych rozwiązań dla układu statek-bierny zbiornik stabilizacyjny.
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Passive sampling and/or extraction techniquesin environmental analysis: a review
PublicationPrzedstawiono przegląd literaturowy dotyczący pasywnych technik izolacji i wzbogacania analitów z matryc środowiskowych, takich jak powietrze, woda czy gleba. Zwrócono uwagę na rosnącą rolę technik pasywnych w monitoringu środowiskowym oraz zaprezentowano krótki rys historyczny rozwoju tych technik.
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The effect of tensile stresses on aluminium passive layer durability
PublicationW niniejszej pracy przedstawiono wyniki badań DEIS dotyczących wpływu naprężeń rozciągających na trwałość warstwy pasywnej aluminium A91050, prowadzonych w środowisku chlorków w temperaturze pokojowej.Zastosowana technika pozwoliła na wyznaczenie krytycznej wartości wydłużenia, przy której doszło do pęknięcia warstwy pasywnej na badanym stopie.
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Algorithms for passive detection of moving vessels in marine environment
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Application of passive sampling techniques for monitoring the aquatic environment
PublicationDozymetry pasywne są coraz powszechniej stosowanym narzędziem do pobierania próbek analitów ze środowiska wodnego. W przypadku próbników pasywnych pobieranie analitów następuje na drodze swobodnego transportu masy przez membranę do medium zatrzymującego, na skutek różnicy potencjałów chemicznych analitów w medium zatrzymującym w próbniku i środowiskiem wodnym, w którym umieszczany jest próbnik. Największą zaletą stosowania próbników...
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Application of passive samplers in monitoring of organic constituents of air
PublicationTechnika dozymetrii pasywnej - znana od ponad 100 lat - cieszy się ciągłym zainteresowaniem i jest często wykorzystywana w różnych badaniach środowiskowych. Z powodu swej prostoty, różnorodności rozwiązań konstrukcyjnych i możliwości wykorzystania różnych technik oznaczeń końcowych, technika dozymetrii pasywnej może być zastosowana zarówno do oznaczeń związków organicznych jak i nieorganicznych, obecnych zarówno w powietrzu wewnętrznym,...
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Surrogate models and automated cad of passive microwave components
PublicationW pracy pokazane zostały techniki modelowania złożonych układów elektronicznych wysokiej częstotliwości. Modele zastępcze mają postać sparametryzowanych modeli matematycznych tworzonych za pomocą schematów interpolacyjnych lub skupionych, pasywnych układów zastępczych dedykowanych analizie w dziedzinie czasu. Do konstrukcji modeli wykorzystywane są wyniki symulacji elektromagnetycznych, co pozwala na osiągnięcie lepszej dokładności...
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Bearing errors passive sonar stationary target location
PublicationPrzedstawiono metodę wyznaczania współrzędnych nieruchomego celu na podstawie namiarów wykonywanych w sonarze pasywnym. Określono wymagania odnośnie ruchu sonaru, przy których błędy wyznaczania współrzędnych są minimalne. Podano zależności umożliwiające analityczne wyznaczanie błędów współrzędnych. Poprawność wyników analizy potwierdzono eksperymentami numerycznymi.
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Experimental investigations on adiabatic frictional pressure drops of R134a during flow in 5mm diameter channel
PublicationThe article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg/m2 s. The frictional pressure drop was characterized for the refrigerant R134a, for vapor qualities ranging from 0 to 1. Long-time thermal stability of test facility allowed to gather...
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Pressure-induced phase transitions in LnTe (Ln=La, Gd, Ho, Yb) and AmTe
PublicationThe structural behaviour under compression of different lanthanide (La, Gd, Ho, Yb) and actinide (Am) monochalcogenides is studied by means of in situ high-pressure x-ray diffraction. All the investigated compounds crystallize at ambient conditions within a cubic (B1) NaCl-type structure but show different behaviours at high pressures. LaTe and AmTe undergo B1 to B2 (CsCl-type structure) phase transitions, starting at 9 GPa and...
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The hydrodynamic pressure field of the ship Zodiak, measurements and calculations
PublicationThe article presents the results of measurements of the slowly changing hydrodynamic pressure field HPF generated by the movement of the ship, Zodiak, in the Bay of Gdansk. The measurement results have been obtained in the framework of the program of the work in Siramis, under the auspices of the European Defence Administration of the EU, by the research team of the Naval Academy in Gdynia. The measurement results were compared with...
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Near-Field Wireless Sensing of Plastics and Papers Using Frugal Peel-Off Passive Tag
PublicationThis article presents a novel frugal approach of testing plastics and papers using a near-field microwave sensing technique with a peel-off tag. The proposed sensing technique involves two electrical entities: the sensor, which may be regarded as a reader, and a disposable tag. The reader is a modified design of a gap-coupled microstrip line (GCML) sensor, while the passive tag is a standard double-ring complementary split-ring...
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Experimental investigations on pressure drop during the condensation in flow of HFE7000 in vertical minichannel
PublicationIn the work presented in the paper authors focused attention on the issues of flow resistance and pressure drop during condensation in the flow. The case of the descending flow through a cylindrical single-channel of 2.3 mm inner diameter was carefully analyzed. In the course of investigations a new working fluid HFE 7000 has been scrutinised which has a strongly differing properties in comparison to the other fluids that are commonly...
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Rare earth ions doped K 2 Ta 2 O 6 photocatalysts with enhanced UV–vis light activity
PublicationNew rare earth-doped K2Ta2O6 photocatalysts were successfully synthesized by hydrothermal method. The effect of dopant type (Y,Yb,Ho,Pr,Er) and amount of rare earth precursor (2,4,8 and 10 mol%) on the physicochemical and photocatalytic properties of RE-K2Ta2O6 have been investigated. All as-prepared materials were characterized by UV–vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller specific surface area measurement,...
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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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Effect of pH and high pressure at sub-zero temperature on the viability of some bacteria
PublicationCelem badań było określenie przeżywalności Escherichia coli i Staphylococcus aureus zawieszonych w soku jabłkowym (pH 3,8) po działaniu ciśnienia 193MPa w temperaturze -20°C. Stwierdzono, że bezpośrednio po działaniu ciśnienia przeżywalność badanych szczepów bakterii nie zmieniała się znacząco. Jednakże liczba komórek zmniejszała się z czasem przechowywania ciśnieniowanych prób. Żywe komórki mikroorganizmów nie były wykrywane w...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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An improved method for flow boiling heat transfer with account of the reduced pressure effect
PublicationIn the paper are presented the results using the authors own model to predict heat transfer coefficient during flow boiling. The model has been tested against a large selection of experimental data to investigate the sensitivity of the in-house developed model. In the work are presented the results of calculations obtained using the semi-empirical model on selected experimental flow boiling data of the refrigerants: R134a, R1234yf,...
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Pressure drop and heat transfer during boiling and condensation at subcritical region
PublicationMost of the data presented in the literature relate to saturation temperatures in the range - 20°C to 40°C due to the application in refrigeration technology. There is necessity to extend databases to higher values of saturation temperature due to new applications such as Organic Rankine Cycle and high temperature heat pumps. Only few papers contain data for high reduced pressure for low boiling point liquids. This paper focus...
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The effect of high pressure on formation of volatile amines in minced meat of cod (Gadus morhua)
PublicationThe effects of high pressure at subzero temperature (193 MPa, at −20 °C) on inactivation of natural microflora of cod meat and degradation of trimethylamine oxide (TMAO) to trimethylamine (TMA) during refrigerated storage and to dimethylamine (DMA) and formaldehyde (FA) during frozen storage were investigated. The content of TMA, DMA and FA in cod meat did not change immediately after pressure treatment. During 40 days of frozen...
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Heat transfer and pressure drop characteristics of the silicone-based plate heat exchanger
PublicationThe paper presents an experimental investigation of a silicone based heat exchanger, with passive heat transfer intensification by means of surface enhancement. The main objective of this paper was to experimentally investigate the performance of a heat exchanger module with the enhanced surface. Heat transfer in the test section has been examined and described with precise measurements of thermal and flow conditions. Reported...
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Longitudinal tracking of muscle sympathetic nerve activity and its relationship with blood pressure in subjects with prehypertension
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Hydrogen production from ethanol In nitrogen microwave plasma At atmospheric pressure
PublicationHydrogen seems to be one of the most promising alternative energy sources. It is a renewable fuel as it could be produced from e.g. waste or bio-ethanol. Furthermore hydrogen is compatible with fuel cells and is environmentally clean. In contrast to conventional methods of hydrogen production such as water electrolysis or coal gasification we propose a method based on atmospheric pressure microwave plasma. In this paper we present...
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A review of rare earth oxides-based photocatalysts: Design strategies and mechanisms
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Structural and electronic properties of some intriguing (rare-earth)Ba2Cu3O7 compounds.
PublicationW rozdziale przedstawiono przegląd wyników eksperymentalnych i teoretycznych dotyczących wybranych związków o wzorze (lantanowiec)Ba2Cu3O7 wykazujących całkowicie odmienne właściwości w porównaniu z całą klasą nadprzewodzących związków tlenkowych o stechiometrii 1:2:3. Szczególny nacisk położono na analizę procesu wzrostu kryształów i powstawania defektów punktowych determinujących późniejsze własności fizyczne tych materiałów....
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Slope Stability Analysis of Zoned Earth Dam with RCC Overtopping Protection
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Thermochemistry of rare earth perovskites Na3xRE0.67−xTiO3 (RE = La, Ce)
PublicationHigh-temperature oxide melt solution calorimetry using sodium molybdate (3Na2O·4MoO3) solvent at 973 K was performed for the Na3xRE0.67−xTiO3 (RE = La, Ce) perovskite series. The enthalpies of formation of lanthanum perovskites from oxides (La2O3, Na2O, TiO2), are −107.25 ± 2.56, −93.83 ± 6.06, −80.68 ± 5.93, and −33.49 ± 4.26 kJ/mol and enthalpies of formation from elements are −1614.05 ± 5.37, −1596.44 ± 7.68, −1594.03 ± 7.58,...
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Environmental aspects of coastal earth structures made of soil-ash composites
PublicationThis paper presents an innovative technology of building the coastal dams with the use of soil-ash composites. A natural- scale test stand and results of the performed environmental tests are presented ; they have been compared with standards for purity of soils and waters. Also, an analysis of the obtained results and discussion of trends and anomalies in the observations, are given.
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Thermal properties of rare earth elements complexes with 1,3,5-benzenetricarboxylic acid
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Designing the Composition of Cement-Stabilized Rammed Earth with the Association Analysis Application
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Characterization and photocatalytic activity of rare earth metal-doped titanium dioxide
PublicationW publikacji została przedstawiona metoda otrzymywania fotokatalizatorów na bazie TiO2 modyfikowanego erbem i iterbem. Otrzymane nanocząstki zostały scharakteryzowane za pomocą powierzchni właściwej BET, objętości porów. Zostały przedstawione widma absorpcyjne UV-Vis oraz właściwości fluorescencyjne otrzymanych nanoproszków. Dokonano również przedstawienia wyników pomiaru aktywności fotokatalitycznej pod wpływem promieniowania...
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The effect of earth fault current harmonics on tripping of residual current devices
PublicationSzerokie zastosowanie przekształtników, a w szczególności przemienników częstotliwości sprawia, że wyłączniki różnicowoprądowe znajdują się w obwodach, w których może płynąć odkształcony prąd ziemnozwarciowy. Prąd ziemnozwarciowy w obwodach z przemiennikami częstotliwości zawiera harmoniczne, których rząd głównie zależy od częstotliwości PWM. Odkształcony prąd wpływa na poprawne wyzwalanie wyłączników różnicowoprądowych. W artykule...
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Pressure in charge. Neglected parameter in hydrothermal synthesis turns out to be crucial for electrochemical properties of ammonium vanadates
PublicationAmmonium vanadates are of great interest as they exhibit unusual electrical and sensory properties.(NH4)2V6O16and (NH4)2V10O25$8H2O with various morphology were obtained in the hydrothermalsynthesis under controlled temperature and pressure. It was shown, that the pure (NH4)2V10O25$8H2Owas obtained under 50 bar of initial pressure, whereas lower pressure lead to the mixture of twocompounds. The influence of the pressure was studied...
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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.