Search
Filters
total: 263
filtered: 228
Search results for: VIRTUAL REALITY, CAVE, SCATTERING DISTRIBUTION FUNCTION, LUMINANCE DISTRIBUTION, UNIFORMITY MEASUREMENT
-
Application of the Barkhausen effect probe with adjustable m agnetic field direction for stress state determination in the P91 ste el pipe
PublicationThe paper presents the results of application of a novel Barkhausen effect (BE) probe with adjustable magnetizing field direction for the stress level evaluation in ferromagnetic materials. The investigated sample was in a form of a pipe, made of P91 steel that was anisotropic due to the production process. The measurements were performed before and after welding, revealing the influence of welding process on the residual stress...
-
The Effect of Flexible Pavement Mechanics on the Accuracy of Axle Load Sensors in Vehicle Weigh-in-Motion Systems
PublicationWeigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature...
-
Elemental and tight monogamy relations in nonsignaling theories
PublicationPhysical principles constrain the way nonlocal correlations can be distributed among distant parties. These constraints are usually expressed by monogamy relations that bound the amount of Bell inequality violation observed among a set of parties by the violation observed by a different set of parties. We prove here that much stronger monogamy relations are possible for nonsignaling correlations by showing how nonlocal correlations...
-
Cost-Effective and Sufficiently Precise Integration Method Adapted to the FEM Calculations of Bone Tissue
PublicationThe technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar...
-
Selected aspects of two-phase flow studies using different visualization techniques in minichannels
PublicationThe subject of the study is to present the possibility of the use of visualization techniques in the researches on two-phase flows, carried out by the authors for many years. These works included as follows: heat transfer during the flow boiling, boiling crises and condensation in flow. The issue of the heat transfer intensification during the flow boiling through the channels of small diameters was analyzed. All this work focused...
-
Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter (PC) suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow easier integration of renewable energy sources and energy storage systems (ESSs), interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and...
-
Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow an easier integration of renewable energy sources and energy storage systems, interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and applications...
-
Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublicationSpatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H2/Ar/CH4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along...
-
Erroneous GNSS Strain Rate Patterns and their Application to Investigate the Tectonic Credibility of GNSS Velocities
PublicationThe paper concerns investigation of the credibility of tectonic interpretation of GNSS strain rates. The analysis was focused on stable regions, where the crustal deformations are small and the reliability of GNSS velocities is questionable. We are showing how the unreliable motion of stations affects calculated strains around them. We expressed distribution of local principal strains by a sinusoidal function and used them to investigate...
-
Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions
PublicationAg-based plasmonic nanostructures were manufactured by thermal annealing of thin metallic films. Structure and morphology were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). SEM images show that the formation of nanostructures is influenced by the initial layer thickness as well as the...
-
A Cross-Polarisation Discrimination Analysis of Off-Body Channels in Passenger Ferryboat Environments
PublicationThere is a need for investigating radio channels for Body Area Networks considering the depolarisation phenomenon and new types of environments, since these aspects are becoming very important for systems design and deployment. This paper presents an analysis of cross-polarisation discrimination for off-body channels based on a measurement campaign performed in a passenger ferryboat, i.e., where all walls, floors and ceilings are...
-
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...
-
Adoption of the F-statistic of Fisher-Snedecor distribution to analyze importance of impact of modifications of injector opening pressure of a compression ignition engine on specific enthalpy value of exhaust gas flow
PublicationThis article analyzes the effect of modifications of injector opening pressure on the operating values of a compression ignition engine, including the temperature of the fumes. A program of experimental investigation is described, considering the available test stand and measurement capabilities. The structure of the test stand on which the experimental measurements were conducted is presented. The method of introducing real modifications...
-
Modulo N Backoff Scheme for effective QoS differentiation and increased bandwidth utilization in IEEE 802.11 networks
PublicationThe paper presents a new "modulo N" channel access scheme for wireless Local Area Networks (WLANs). The novel solution derives from the Distributed Coordination Function (DCF) of the IEEE 802.11 standard, further elaborated as Enhanced Distribution Channel Access (EDCA) by the 802.11e draft specification. The main innovation concerns improvement of the binary exponential backoff scheme used for collision avoidance in 802.11 networks....
-
The model of end-to-end call setup time calculation for Session Initiation Protocol
PublicationEnd-to-end call setup delay is one of the most important grade of service (GoS) parameters for VoIP networks with Session Initiation Protocol (SIP). A typical subscriber wants to have a connection established as soon as possible. From the operator's perspective call setup time is also crucial because he needs to know how probability of successful packet transmission on SIP links is related to a call setup delay. Then he can make...
-
Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
-
A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublicationA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
-
Optical flow method for measuring deformation of soil specimen subjected to torsional shearing
PublicationIn this study optical flow method was used for soil small deformation measurement in laboratory tests. The main objective was to observe how the deformation distributes along the whole height of cylindrical soil specimen subjected to torsional shearing (TS test). The experiments were conducted on dry non-cohesive soil specimens under two values of isotropic pressure. Specimens were loaded with low-amplitude cyclic torque to analyze...
-
Experiment-Based Study of Heat Dissipation from the Power Cable in a Casing Pipe
PublicationThe paper deals with the important challenges in terms of electricity transmission by means of underground cable lines. The power cable’s performance is characterized by an ampacity that represents its maximum electric current-carrying capacity. The ampacity of power cables depends on their ability to diffuse the heat generated by the current flow into the environment. In the performed research, the analysis of the efficiency of...
-
Detection and time/frequency analysis of electric fields in the ground
PublicationThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
-
Influence of meniscus shape in the cross sectional plane on the knee contact mechanics
PublicationWe present a three dimensional finite element analysis of stress distribution and menisci deformation in the human knee joint. The study is based on the Open Knee model with the geometry of the lateral meniscus which shows some degenerative disorders. The nonlinear analysis of the knee joint under compressive axial load is performed. We present results for intact knee, knee with partial and complete radial posterior meniscus root...
-
The impact of security aspects on functional safety analysis = Wpływ aspectów ochrony informacji na wyniki analiz bezpieczeństwa funkcjonalnego
PublicationIt can be said that a distributed control and protection system’s security level may have a significant impact on functional safety analyses and their results. However the issue of integrating those both aspects are difficult and usually is neglected during functional safety analyses. Known methods of functional safety analyses don’t take into consideration this kind of concept also. This paper discusses an attempt to integrate...
-
Thermal visualization of Ostwald-de Waele liquid in wavy trapezoidal cavity: Effect of undulation and amplitude
PublicationThe present study is concerned with the numerical simulations of Ostwald-de Waele fluid flow in a wavy trapezoidal cavity in the presence of a heated cylinder situated at the center of the cavity. The work consists in characterizing the mixed convection as a function of the intensity of heat flow. The flow behaviour and temperature distribution in a cavity are the main focus of this study. The lower wall of the cavity is fixed...
-
Non-Gaussian Resistance Fluctuations in Gold-Nanoparticle-Based Gas Sensors: An Appraisal of Different Evaluation Techniques
PublicationVolatile organic compounds, such as formaldehyde, can be used as biomarkers in human exhaled breath in order to non-invasively detect various diseases, and the same compounds are of much interest also in the context of environmental monitoring and protection. Here, we report on a recently-developed gas sensor, based on surface-functionalized gold nanoparticles, which is able to generate voltage noise with a distinctly non-Gaussian...
-
Fracture surface formation of notched 2017A-T4 aluminium alloy under bending fatigue
PublicationThe effect of cyclic loading on facture surface topology in notched components made by aluminium alloys is not completely clear. Fractogra-phy and fracture mechanics can help to understand this interdependency. This paper aims to study the distribution of the fracture surface roughness of notched 2017A-T4 aluminium alloy after bending fatigue using an optical focus-variation surface measurement technique by applying the fracture...
-
Heterogeneity of national accounting systems, world-class universities and financial resources: What are the links?
PublicationThis study investigates the relationship between university financial resources, applied accounting systems, and the place of a university in the Shanghai Ranking. We find a strong relationship between the financial resources under the control of a world-class university and the position of that university in the highest tier of the global ranking. We propose a model (available online) to predict a university’s tier in the ranking...
-
Miniaturized Metal-Mountable U-shaped Inductive-Coupling-Fed UHF RFID Tag Antenna with Defected Microstrip Surface
PublicationThis study presents a novel miniature ultra-high frequency (UHF) radio frequency identification (RFID) tag for metallic objects. Its arrangement includes a U-shaped feeder, which is inductively coupled to two E-type connected patches. Size reduction is achieved by means of utilizing the U-shaped feeder, and introducing a defection in the connection between the two E-type patches. The defection in the connection area between the...
-
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...
-
Modelowanie wymiany wody w zbiornikach hodowlanych przy użyciu zmodyfikowanego modelu tłokowego na przykładzie basenów hodowlanych dla fok
PublicationNiniejszy artykuł opisuje sposób prostego modelowania wymiany wody w basenach hodowlanych fokarium Stacji Morskiej Instytutu Oceanografii Uniwersytetu Gdańskiego. W celu rozpoznania warunków wymiany wody oraz udziału stref zastoiskowych w basenach posłużono się dwiema uzupełniającymi się metodami. Były to badania traserowe z wykorzystaniem znacznika fluororescencyjnego oraz komputerowe obliczenia rozkładu linii prądu z użyciem...
-
Analiza parametrów płukania sieci wodociągowej metodą ukierunkowanego przepływu wody
PublicationEksperymenty prowadzone przez wiele lat podczas płukania sieci wodociągowej metodą jednokierunkowego przepływu wody umożliwiają weryfikację interakcji między jakością wypłukiwania nagromadzonych zanieczyszczeń oraz parametrami przepływu, liczbą cykli wymiany wody, a także zasięgiem płukania. Usuwanie zanieczyszczeń na początku przebiega zgodnie z szybko rosnącą krzywą, a następnie według funkcji malejącej. Taki przebieg jest spowodowany...
-
CZYNNIKI DECYDUJĄCE O PRZYDATNOŚCI KOMPUTEROWEGO MODELU PRZEPŁYWÓW W SIECI WODOCIĄGOWEJ
PublicationW pracy poddano analizie wielozadaniowy proces tworzenia komputerowego modelu przepływów. W efekcie zidentyfikowano szereg czynników ograniczających obszar stosowania modelu w praktyce inżynierskiej. W zakresie pozyskiwania danych strukturalnych i operacyjnych wskazano potencjalne źródła błędów, które przyczyniają się do zmniejszenia dokładności odwzorowania stanu rzeczywistego. Specjalną rangę nadano specyfikacji czynników związanych...
-
Double-diffusive natural convection energy transfer in magnetically influenced Casson fluid flow in trapezoidal enclosure with fillets
PublicationThe prime motive of this disquisition is to deal with mathematical analysis of natural convection energy transport driven by combined buoyancy effects of thermal and solutal diffusion in a trapezoidal enclosure. Casson fluid rheological constitutive model depicting attributes of viscoelastic liquids is envisioned. The influence of the inclined magnetic field governed by Lorentz field law is also considered. To raise the essence...
-
ASSESSING THE POTENTIAL REPLACEMENT OF MINERAL OIL WITH ENVIRONMENTALLY ACCEPTABLE LUBRICANTS IN A STERN TUBE BEARING: AN EXPERIMENTAL ANALYSIS OF BEARING PERFORMANCE
PublicationT his study compares the performance of a plain bearing, with a similar structure to a tail shaft stern bearing, lubricated with either mineral oil or an environmentally acceptable lubricant (EAL). The main characteristic of the bearing is its length/diameter ratio of <1. Measurements are carried out with the bearing operating under loads from 0.5 to 1 MPa and seven speeds ranging from 1 to 11 rev/s. The bearing lubricated...
-
3D MODELLING OF CYLINDRICAL-SHAPED OBJECTS FROM LIDAR DATA - AN ASSESSMENT BASED ON THEORETICAL MODELLING AND EXPERIMENTAL DATA
PublicationDespite the increasing availability of measured laser scanning data and their widespread use, there is still the problem of rapid and correct numerical interpretation of results. This is due to the large number of observations that carry similar information. Therefore, it is necessary to extract from the results only the essential features of the modelled objects. Usually, it is based on a process using filtration, followed by...
-
Stable and degradable microgels linked with cystine for storing and environmentally triggered release of drugs
PublicationEnvironmentally sensitive, degradable microgels based on poly(N-isopropylacrylamide) (pNIPA) crosslinked with the diacryloyl derivative of cystine (BISS) were synthesized by applying surfactant-free emulsion polymerization. pNIPA contributed the sensitivity to temperature to the microgels and the cross-linker made them degradable and sensitive to pH. The morphology of the microgels was investigated by using scanning and transmission...
-
The effect of microemulsion composition on the morphology of Pd nanoparticles deposited at the surface of TiO2 and photoactivity of Pd-TiO2
PublicationA series of microemulsion (ME) system, constituted by different water to surfactant molar ratios (Wo) and oil to surfactant mass ratios (S), have been applied for Pd-TiO2 preparation. The effect of ME properties on the morphology of Pd nanoparticles formed at TiO2 surface and an effect of Pd size and distribution on the surface and photocatalytic properties of Pd-TiO2 were investigated. Microemulsion systems were characterized...
-
Distortion of speech signals in the listening area: its mechanism and measurements
PublicationThe paper deals with a problem of the influence of the number and distribution of loudspeakers in speech reinforcement systems on the quality of publicly addressed voice messages, namely on speech intelligibility in the listening area. Linear superposition of time-shifted broadband waves of a same form and slightly different magnitudes that reach a listener from numerous coherent sources, is accompanied by interference effects...
-
Molecular hydrogen solvated in water – A computational study
PublicationThe aqueous hydrogen molecule is studied with molecular dynamics simulations at ambient temperature and pressure conditions, using a newly developed flexible and polarizable H2 molecule model. The design and implementation of this model, compatible with an existing flexible and polarizable force field for water, is presented in detail. The structure of the hydration layer suggests that first-shell water molecules accommodate the...
-
Bearing capacity of working platform using distinct layout optimization method
PublicationBearing capacity of the working platforms from sandy soil resting on NC and OC clays was analyzed using LimitState GEO program. Different failure modes are considered using distinct layout optimization (DLO) method, which forms the upper bound solution of limit state analysis. Different mechanisms of failure were observed as a function of the platform thickness, angle of internal friction of the platform material and undrained...
-
Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in an indoor environment (a medium-size room with furniture, mostly consisting of wooden tables and chairs) have been measured:...
-
Improving performance of large thrust bearings through modeling and experimentation
PublicationLarge thrust bearings are highly loaded machine elements and their failures cause serious losses. Start ups and stoppages of the bearing under load are specially critical regimes of operation. Load carrying capacity depends on the profile of the oil gap. In transient states this profile is also changing. In the design of large thrust bearings minimizing thermo-elastic deformations is an important goal, which can be accomplished...
-
Modeling of Electrified Transportation Systems Featuring Multiple Vehicles and Complex Power Supply Layout
PublicationThe paper proposes a novel approach to modeling electrified transportation systems. The proposed solution reflects the mechanical dynamics of vehicles as well as the distribution and losses of electric supply. Moreover, energy conversion losses between the mechanical and electrical subsystems and their bilateral influences are included. Such a complete model makes it possible to replicate, e.g., the impact of voltage drops on vehicle...
-
Evaluation of the significance of the effect of the active cross-sectional area of the inlet air channel on the specific enthalpy of the exhaust gas of a diesel engine using statistics F of the Fisher-Snedecor distribution
PublicationThis paper presents the application of Fisher-Snedecor distribution F statistics to assess the significance of the influence of changes in the active cross-sectional area of the inlet air channel (Adol) flow in a diesel engine on the observed diagnostic parameter determined on the basis of measurements of the quick changing exhaust gas temperature in the outlet channel, which is the specific enthalpy of the exhaust gas stream within...
-
Methodology of research on the impact of ITS services on the safety and efficiency of road traffic using transport models
PublicationThe current assessment of the impact of Intelligent Transport System (ITS) services on the level of traffic safety and efficiency is based mainly on expert assessments, statistical surveys or several traffic safety models requiring development. There is no structured, uniform assessment method that would give the opportunity to compare the impact of ITS services and their different configurations. The paper presents the methodology...
-
Noise and Electro-Ultrasonic Spectroscopy of Conducting PolymerThick Films
PublicationThick conducting films based on conducting polymer are characterized by DC conductivity and noise in temperature range 10 to 300 K. Conducting polymers could be used e.g. for the top electrode (cathode) in the solid tantalum or niobium capacitors. On the conducting polymer layer the top layer of carbon/graphite and/or silver polymer based pastes is applied in the capacitor technology. Our samples structure consists of conducting...
-
Designing acoustic scattering elements using machine learning methods
PublicationIn the process of the design and correction of room acoustic properties, it is often necessary to select the appropriate type of acoustic treatment devices and make decisions regarding their size, geometry, and location of the devices inside the room under the treatment process. The goal of this doctoral dissertation is to develop and validate a mathematical model that allows predicting the effects of the application of the scattering...
-
Analysis of antibiotic resistance in Escherichia coli isolated from the Reda River and the Oliwski Stream using basic statistical methods = Zastosowanie metod ststystycznych do analizy antybiotykoodporności bakterii wskaźnikowych pochodzących z rzeki Redy i Potoku Oliwskiego
PublicationIn this study distribution of antimicrobial resistance patterns among fecal indicator bacteria (Escherichia coli and Enterococcus spp.) was examined in two watercourses. The susceptibility analyses were carried out against the antimicrobial agents, important in treating human E. coli and enterococcal infection. Water samples were obtained from the Oliwski Stream and from the Reda River. On each watercourse the five representative...
-
Deposition and Electrical and Structural Properties of La0.6Sr0.4CoO3 Thin Films for Application in High-Temperature Electrochemical Cells
PublicationLow-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-lm-thick La0.6Sr0.4CoO3d (LSC) perovskite with high electrical conductivity on sapphire substrates at 400C and analyzed its...
-
Theoretical calculation of the physico-chemical properties of 1-butyl-4-methylpyridinium based ionic liquids
PublicationACCEPTED MAIonic liquids (ILs) have attracted much attention for their unique physicochemical properties, which can be designed as needed by altering the ion combinations. Besides experimental work, numerous computational studies have been concerned with prediction of physical properties of ILs. The results of molecular dynamics simulations of ILs depend strongly on the proper force field parameterization. Classical force fields...
-
Comparison of target strength (TS) distributions obtained by means of the use of direct and indirect techniques in sea cages
PublicationThe aim of this study is to verify the reliability of a processing application developed for the indirect measurement of target strength (TS), with a view to the integration into a single-beam system for its utilization in fish farms. Dorsal and ventral measurements are carried out for gilt-head sea-bream (Spams Aurata) for 5 size classes using a split-beam EK60 echosounder and single-beam data obtained from one of the channels...