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Search results for: INFORMATION CHANNEL
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Calculations of the resistance values of 20 thermistors at 0°C
Open Research DataThe presented data set is part of the research aimed at determining the actual characteristics of each thermistor in a package of twenty NTC10k type sensors.
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The Weibull model of the multipath fading channel
Open Research DataThe dataset contains the results of simulations that are part of the research on modelling the multipath fading in the communication channel. The Weibull fading envelope is generated using the Monte-Carlo simulation (MCS) in the LabVIEW programming environment.
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Validation of atmospheric aerosols parallel sampling in a multifold device
PublicationIn this work, particulate matter was collected using an active sampling system consisting of a PM10 (<10 μm) inlet coupled to a multifold device containing six channels, connected to a vacuum pump. Each channel was equipped with a filter holder fitted with adequately chosen filters. The system was fixed on a metallic structure, which was placed on the roof of the laboratory building, at the Faculty of Sciences, in Lisbon. Sampling...
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Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels
PublicationAttention is focused on the issues of flow resistance and pressure drop of perspective refrigeration fluids during condensation in the two-phase flow in minichannels. The case of the flow through a cylindrical single channel of 2.3 mm inner diameter was carefully analyzed. Pressure drop tests have been performed in diabatic flow conditions. The effect of heat flux, mass flux, vapour quality and saturation temperature on the two-phase...
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Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea
PublicationDissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation...
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Prediction of coking dynamics for wet coal charge
PublicationA one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal...
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Investigation of natural frequencies of axially loaded thin-walled columns
PublicationThe paper deals with correlation between natural frequencies of two steel thin-walled columns and the corresponding applied load. The structures are made of cold-formed lipped channel sections. The columns lengths were assumed to follow two buckling patterns – global flexural and flexural-torsional buckling. In the thicker structure two material models were considered – linearly-elastic and elastic-perfectly plastic. Numerical...
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Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
PublicationDoppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler...
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LOS and NLOS identification in real indoor environment using deep learning approach
PublicationVisibility conditions between antennas, i.e. Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) can be crucial in the context of indoor localization, for which detecting the NLOS condition and further correcting constant position estimation errors or allocating resources can reduce the negative influence of multipath propagation on wireless communication and positioning. In this paper a deep learning (DL) model to classify LOS/NLOS...
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The impact of gender wage gap on sectoral economic growth – cross-country approach
PublicationWe propose an empirical analysis of testing the relationship between gender wage gap and economic growth. The study takes into account 12 manufacturing sectors in 18 OECD countries for the period between 1970 and 2005.We use industrial statistics (EU KLEMS, 2008) on female and male wages that distinguish between wages paid to different groups of workers classified according to skill level: high, medium and low. We estimate augmented...
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Graphene field-effect transistor application for flow sensing
PublicationMicroflow sensors offer great potential for applications in microfluidics and lab-on-a-chip systems. However, thermal-based sensors, which are commonly used in modern flow sensing technology, are mainly made of materials with positive temperature coefficients (PTC) and suffer from a self-heating effect and slow response time. Therefore, the design of novel devices and careful selection of materials are required to improve the overall...
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Hydroperoxyl radical and formic acid formation from common DNA stabilizers upon low energy electron attachment
Publication2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) and ethylenediaminetetraacetic acid (EDTA) are key components of biological buffers and are frequently used as DNA stabilizers in irradiation studies. Such surface or liquid phase studies are done with the aim to understand the fundamental mechanisms of DNA radiation damage and to improve cancer radiotherapy. When ionizing radiation is used, abundant secondary electrons are formed...
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Radio Channel Measurements in 868 MHz Off-Body Communications in a Ferry Environment
PublicationIn this paper, a characterization of the 868 MHz off-body radio channel in BANs is presented. Measurements were carried out in a ferry environment using a specific set-up. A method for path loss using radio distance measurements (RDMs) was developed. It allows to automate the measurements process and make it independent from the variable speed of a moving person. Based on the observed path loss as a function of distance, the obtained...
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Image transmission in UAV MIMO UWB-OSTBC system over Rayleigh channel using multiple description coding (MDC)
PublicationOrthogonal Space-Time Block Codes (OSTBC) and multiple-input-multiple-output (MIMO) communication system are new techniques with high performance that have many applications in wireless telecommunications. This chapter presents an image transfer technique for the unmanned aerial vehicle (UAV) in a UWB system using a hybrid structure of the MIMO-OSTBC wireless environment in multiple description coding (MDC) deals. MDC technique...
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Organic Vapor Sensing Mechanisms by Large-Area Graphene Back-Gated Field-Effect Transistors under UV Irradiation
PublicationThe gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced...
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Analyzing Preconditions to Introduce Internet Voting in Portugal: Insights from the Estonian Model
PublicationInternet voting has been trialed or introduced for several countries, including Norway, Portugal, United States, United Kingdom and Switzerland as an additional voting channel to increase voter turnout and, also to modernize the electoral process. However, only Estonia has successful introduced internet voting, deploying e-enabled elections in general governmental levels. This paper aims to provide an exploratory study on the Estonian...
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Study of ZrS3-based field-effect transistors toward the understanding of the mechanisms of light-enhanced gas sensing by transition metal trichalcogenides
PublicationExtending knowledge of the properties of low-dimensional van der Waals materials, including their reactivity to the ambiance, is important for developing innovative electronic and optoelectronic devices. Transition metal trichalcogenides with tunable optical band gaps and anisotropic conductivity are an emerging class among low- dimensional structures with the possibility of gate tunability and photoreactivity. These properties...
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Investigations of the valence state of Co in a MnCoO ceramics
Open Research DataMcCoO ceramics materials were produced by solid state reaction and sintred in a furnance in air atmosphere for 20h. Annealing temperature was 600 Celsius degree. For investigations a series of samples, with a various composition was chosen: MnCoO, Mn, Co2O and Mn2CoO. Chemical behaviour of the Cobaltium was measured by XPS method. The analyses were...
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Vehicular Communication Environments
PublicationCommunication to and between road vehicles (cars, truck, buses, trains, etc.) are of growing interest. This is partly due to the attractive services that cooperative intelligent transport systems (C-ITSs) provides, mainly in the areas of traffic safety and traffic efficiency. An enabler for C-ITS is wireless vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication, collectively referred to as vehicle-to-X (V2X)...
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Dissociative ionization dynamics of dielectric gas C3F7CN
PublicationFluoronitrile C3F7CN is a promising candidate for the replacement of SF6 dielectric gas in high-voltage insulation. We present a combined experimental and theoretical study on its ionization dynamics probed in the 0-100 eV energy range. We exploited the total ion collection technique to determine the absolute ionization cross section, mass spectrometry to determine the fragment branching ratios and ab initio nonadiabatic molecular...
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Recent Achievements in Constitutive Equations of Laminates and Functionally Graded Structures Formulated in the Resultant Nonlinear Shell Theory
PublicationThe development of constitutive equations formulated in the resultant nonlinear shell theory is presented. The specific features of the present shell theory are drilling rotation naturally included in the formulation and asymmetric measures of strains and stress resultants. The special attention in the chapter is given to recent achievements: progressive failure analysis of laminated shells and elastoplastic constitutive relation...
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Scheduling for Industrial Control Traffic Using Massive MIMO and Large Intelligent Surfaces
PublicationIndustry 4.0, with its focus on flexibility and customizability, is pushing in the direction of wireless communication in future smart factories, in particular massive multiple-input multiple-output (MIMO), and its future evolution Large Intelligent Surfaces (LIS), which provide more reliable channel quality than previous technologies. As such, there arises the need to perform efficient scheduling of industrial control traffic...
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Electron-Induced Decomposition of 5-Bromo-4-thiouracil and 5-Bromo-4-thio-2′-deoxyuridine: The Effect of the Deoxyribose Moiety on Dissociative Electron Attachment
PublicationWhen modified uridine derivatives are incorporated into DNA, radical species may form that cause DNA damage. This category of molecules has been proposed as radiosensitizers and is currently being researched. Here, we study electron attachment to 5-bromo-4-thiouracil (BrSU), a uracil derivative, and 5-bromo-4-thio-20 -deoxyuridine (BrSdU), with an attached deoxyribose moiety via the N-glycosidic (N1-C) bond. Quadrupole mass spectrometry...
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AN INTELLIGENT SYSTEM TO SUPPORT THE DESIGN PROCESS OF HYBRID PHOTOVOLTAIC INSTALLATIONS
PublicationThe paper presents the final version of intelligent system to support the design process of hybrid photovoltaic systems supported by fuel cells and / or thermoelectric generators developed and constructed at the Institute of Electron Technology, as well as to conduct experiments and research. A block diagram of the system and the selection of its components is described and discussed. The paper considers the availability of the...
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POSSIBILITY OF ASSESSMENT OF OPERATION OF SLIDING BEARINGS IN PISTON-CRANK MECHANISMS OF DIESEL ENGINES WITH REGARD TO LOAD AND TIME OF CORRECT WORK OF THE BEARINGS BY APPLYING ACOUSTIC EMISSION AS A DIAGNOSTIC SIGNAL
PublicationAbstract: The paper presents a possibility of determining (assessing) operation of sliding bearings with multilayer bushings in crank-piston mechanisms of diesel engines. Properties of load and wear, particularly fatigue and abrasive, are characterized in general. Acoustic emission as a diagnostic signal was proved to be useful for detection of the wear of sliding and barrier layers. Results of measurements of acoustic emission...
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A Wideband Channel Model for Body Area Networks in Circular Metallic Indoor Environments
PublicationIn this paper, the wideband characterization of the propagation channel in circular metallic indoor environments is addressed, regarding Body Area Networks and 5G small cells, an analytical model for the dependence of the mean delay and the average delay spread on the circle radius, the working frequency and the distance between the transmitter and the receiver being proposed. The derivation of the model is initially done analytically,...
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Adaptive identification of sparse underwater acoustic channels with a mix of static and time-varying parameters
PublicationWe consider identification of sparse linear systems with a mix of static and time-varying parameters. Such systems are typical in underwater acoustics (UWA), for instance, in applications requiring identi- fication of the acoustic channel, such as UWA communications, navigation and continuous-wave sonar. The recently proposed fast local basis function (fLBF) algorithm provides high performance when identi- fying time-varying systems....
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XPS study of the YST ceramics
Open Research DataYttrium-doped strontium titanate was prepared via conventional solid-state reaction method from Y2O3 (Sigma Aldrich, 99,9%), TiO2 (Sigma Aldrich, 99%) and SrCO3 (Sigma Aldrich,98%). For comparision, two other techniques were used for synthesis: Pechini and wet methods. Both kind of samples were measured, after and before reduction process (in a hydrogen)....
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Substrate characterization in a electrochemically derived Manganium-Cobaltium thin films
Open Research DataManganium-Cobaltium thin films were electrochemically deposited on a Ni foams subsrates in a one-step process at −1.1 V vs. Ag/AgCl in an aqueous solution of differently concentrated Mn(NO3)2·4H2O and Co(NO3)2·6H2O with the deposition time limited by charges of 60, 120, and 200 mC at 25 °C. The concentration ratios of Mn(NO3)2·4H2O to Co(NO3)2·6H2O...
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Chemical analysis of the Au-Ag nanoaloys
Open Research DataThe nanostructures of AuAg nanoalloys were prepared by sequential sputtering of gold and silver thin films. Single layer thickness was usually 2.8 nm were deosted by magnetron sputtering method in a Ar plasma. As deposited layers were annealed in Ar atmosphere at 550 degress for 15 minutes. For XPS measurements five samples were selected: pure gold...
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On local buckling of cold-formed channel members
PublicationThe paper deals with local buckling of the compressed flanges of cold-formed thin-walled channel beams subjected to pure bending or axially compressed columns. Arbitrarily shaped flanges of open cross-sections and the web-flange interactions are taken into account. Buckling deformation of a beam flange is described by displacement related to torsion of the flange about the line of its connection with the web. Total potential energy...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Balance errors generated by numerical diffusion in the solution of non-linear open channel flow equations
PublicationThe paper concerns the untypical aspect of application of the dissipative numerical methods to solve nonlinear hyperbolic partial differential equations used in open channel hydraulics. It is shown that in some cases the numerical diffusion generated by the applied method of solution produces not only inaccurate solution but as well as a balance error. This error may occur even for an equation written in the conservative form not...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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A survey on network resiliency methodologies against weather-based disruptions
PublicationDue to the increasing dependence on network services of our society, research has recently been concentrating on enhancing traditional protection strategies to withstand large-scale failures, as in case of disaster events. The recently-formed EU-funded RECODIS project aims at coordinating and fostering research collaboration in Europe on disaster resiliency in communication networks. In particular, the Working Group (WG) 2 of the...
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Modeling two phase flow in large scale fractured porous media with an extended multiple interacting continua method
PublicationWe present a two phase flow conceptual model, the corresponding simulator (2pMINC) and a workflow for large-scale fractured reservoirs, based on a continuum fracture approach which uses the multiple interacting continua (MINC) method complemented with an improved upscaling technique. The complex transient behavior of the flow processes in fractured porous media is captured by subgridding the coarse blocks in nested volume elements...
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Bees Detection on Images: Study of Different Color Models for Neural Networks
PublicationThis paper presents an approach to bee detection in video streams using a neural network classifier. We describe the motivation for our research and the methodology of data acquisition. The main contribution to this work is a comparison of different color models used as an input format for a feedforward convolutional architecture applied to bee detection. The detection process has is based on a neural binary classifier that classifies...
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An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferry Environment
PublicationIn the article an off-body narrowband and ultra-wide band channel model for Body Area Networks in a ferry environment is described. A mobile, heterogeneous measurement stand, that consists of three types of devices: miniaturized mobile nodes, stationary reference nodes and a data acquisition server was developed. A detailed analysis of both radio channels parameters in untypical indoor environment was carried out. An analysis of...
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Time Delay Estimation in Two-Phase Flow Investigation Using the γ-Ray Attenuation Technique.
PublicationTime delay estimation is an important research question having many applications in a range of technologies. Measurement of a two-phase flow in a pipeline or an open channel using radioisotopes is an example of such application. For instance, the determination of velocity of dispersed phase in that case is based on estimation of the time delay between two stochastic signals provided by scintillation probes. The proper analysis...
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Discouraging Traffic Remapping Attacks in Local Ad Hoc Networks
PublicationQuality of Service (QoS) is usually provided in ad hoc networks using a class-based approach which, without dedicated security measures in place, paves the way to various abuses by selfish stations. Such actions include traffic remapping attacks (TRAs), which consist in claiming a higher traffic priority, i.e., false designation of the intrinsic traffic class so that it can be mapped onto a higher-priority class. In practice, TRAs...
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Reliable routing and resource allocation scheme for hybrid RF/FSO networks
PublicationSignificant success of wireless networks in the last decade has changed the paradigms of communication networks design. In particular, the growing interest in wireless mesh networks (WMNs) is observed. WMNs offer an attractive alternative to conventional cable infrastructures, especially in urban areas, where the cost of new installations is almost prohibitive. Unfortunately, the performance of WMNs is often limited by the cluttered...
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Methods of Determining Pressure Drop in Internal Channels of a Hydraulic Motor
PublicationIn this paper, new methods for determining the pressure drop in internal channels of a hydraulic motor are proposed and described. Mathematical models of pressure losses in internal channels have also been described. Experimental tests of the satellite motor were carried out according to one of the proposed methods. The tests were carried out for two liquids, i.e., water and mineral oil. Experimental studies have shown that at...
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Detection and Direction-of-Arrival Estimation of Weak Spread Spectrum Signals Received with Antenna Array
PublicationThis paper presents a method for the joint detection and direction of arrival (DOA) estimation of low probability of detection (LPD) signals. The proposed approach is based on using the antenna array to receive spread-spectrum signals hidden below the noise floor. Array processing exploits the spatial correlation between phase-delayed copies of the signal and allows us to evaluate the parameter used to make the decision about the...
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Mitigating Traffic Remapping Attacks in Autonomous Multi-hop Wireless Networks
PublicationMultihop wireless networks with autonomous nodes are susceptible to selfish traffic remapping attacks (TRAs). Nodes launching TRAs leverage the underlying channel access function to receive an unduly high Quality of Service (QoS) for packet flows traversing source-to-destination routes. TRAs are easy to execute, impossible to prevent, difficult to detect, and harmful to the QoS of honest nodes. Recognizing the need for providing...
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DLC coating in ring-on-ring sliding with water lubrication 10MPa/0.1m/s
Open Research DataWear tests in sliding friction of DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 10MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: WATER. Tribometer: PT-3. Overall test time >15h. The test was augmented by vibration...
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DLC coating in ring-on-ring sliding with saline solution (0.9% wt.) lubrication 20MPa/0.1m/s
Open Research DataWear tests in sliding friction of DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 20MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9% wt.). Tribometer: PT-3. Overall test time >15h. The test was augmented...
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DLC coating in ring-on-ring sliding with saline solution (0.9% wt.) lubrication 10MPa/0.1m/s
Open Research DataWear tests in sliding friction of DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 10MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9% wt.). Tribometer: PT-3. Overall test time >15h. The test was augmented...
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DLC coating in ring-on-ring sliding with water lubrication 20MPa/0.1m/s
Open Research DataWear tests in sliding friction of DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 20MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: WATER. Tribometer: PT-3. Overall test time >15h. The test was augmented by vibration...
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DLC coating doped with W in ring-on-ring sliding with water lubrication 20MPa/0.1m/s
Open Research DataWear tests in sliding friction of 1% W (tungsten) doped DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 20MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: WATER. Tribometer: PT-3. Overall test time >15h. The test was...
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DLC coating doped with W in ring-on-ring sliding with water lubrication 10MPa/0.1m/s
Open Research DataWear tests in sliding friction of 1% W (tungsten) doped DLC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, DLC-W over DLC-W. Mean contact stress: 10MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: WATER. Tribometer: PT-3. Overall test time >15h. The test was...