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Dynamic effect of the vehicle passing under lightweight footbridge.
PublikacjaThe paper describes a numerical study of dynamic response of cable-stayed steel footbridge for a big lorry passing underneath. The footbridge is an existing object crossing Wolska street in Warsaw. The structural model of footbridge was verified by dynamic test loading. A numerical study of a vehicle passing under footbridge is presented. 2D and 3D incompressible flow fields are modeled using sliding mesh in transient CFD computation....
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Action-reaction based synthesis of acoustic wavefield equations
PublikacjaThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...
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Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublikacjaThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
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Effect of Maximal Breath Hold Apnea on Pial Artery Pulsation and Subarachnoid Width in Human
PublikacjaLittle is known about intracranial pressure (ICP)-cerebral hemodynamic interplay during maximal breath-hold apnea. A recently developed method based on near-infrared transillumination/backscattering sounding (NIR-T/BSS) noninvasively measures changes in pial artery pulsation (cc-TQ) as well as subarachnoid width (sas-TQ) in humans. Changes in sas-TQ correlate with ICP to a considerable extent, whereas cc-TQ reflects the functional...
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Handwritten signature verification system employing wireless biometric pen
PublikacjaThe handwritten signature verification system being a part of the developed multimodal biometric banking stand is presented. The hardware component of the solution is described with a focus on the signature acquisition and on verification procedures. The signature is acquired employing an accelerometer and a gyroscope built-in the biometric pen plus pressure sensors for the assessment of the proper pen grip and then the signature...
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Structure redetermination, transport and thermal properties of the YNi3Al9 compound
PublikacjaSingle crystals of completely ordered variant of the YNi3Al9 compound were grown by self-flux method with excess of aluminum. The crystal structure of the title compound was redetermined from single crystal X-ray diffraction data. The structure adopts ErNi3Al9 type, space group R32, parameters of the unit cell a = 7.2838(2) Å, c = 27.4004(8) Å. The growth of relatively large single crystals of the YNi3Al9 compound, having completely...
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Compact Quasi-Elliptic-Type Inline Waveguide Bandpass Filters With Nonlinear Frequency-Variant Couplings
PublikacjaThis work presents the design techniques to synthesize a class of compact inline quasi-elliptic-type waveguide cavity bandpass filters based on novel nonlinear frequency-variant couplings (NFVCs). These highly dispersive frequency-variant couplings (FVCs) are realized by means of a pair of partial-height posts that are placed at the junctions between every two cavity resonators. Each NFVC produces a transmission pole in between...
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Evolution of charge density wave order in continuous solid solutions Lu(Ni1-xCox)C2
PublikacjaPseudo-ternary solid solutions, Lu(Ni1-xCox)C2 (0 ≤ x ≤ 1), were studied by means of powder X-ray diffraction, differential thermal analysis as well as electrical resistivity and heat capacity measurements. The crystal structure of the Lu(Ni1-xCox)C2 series, as investigated by means of X-ray powder diffraction, is of structure type CeNiC2, space group Amm2, Pearson symbol oS8. The structural analysis reveals a non-monotonous evolution,...
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Large magnetoresistance and first-order phase transition in antiferromagnetic single-crystalline EuAg4Sb2
Publikacjapresent the results of a thorough investigation of the physical properties of single crystals using magnetization, heat capacity, and electrical resistivity measurements. High-quality single crystals, which crystallize in a trigonal structure with space group , were grown using a conventional flux method. Temperature-dependent magnetization measurements along different crystallographic orientations confirm two antiferromagnetic...
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Development of an AI-based audiogram classification method for patient referral
PublikacjaHearing loss is one of the most significant sensory disabilities. It can have various negative effects on a person's quality of life, ranging from impeded school and academic performance to total social isolation in severe cases. It is therefore vital that early symptoms of hearing loss are diagnosed quickly and accurately. Audiology tests are commonly performed with the use of tonal audiometry, which measures a patient's hearing...
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System Weryfikacji Autentyczności Podpisu Odręcznego
PublikacjaW referacie przedstawiono system statycznej i dynamicznej weryfikacji autentyczności podpisu odręcznego, składanego piórem biometrycznym, wyposażonym w 2 akcelerometry, 2 żyroskopy i 3 czujniki ścisku, na rezystancyjnej powierzchni dotykowej, łączącym się bezprzewodowo z urządzeniami komputerowymi. We wstępie przedstawiono architekturę sieciową wielomodalnego systemu biometrii. Przedstawiono warstwę sprzętową systemu weryfikacji...
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On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages
PublikacjaThis paper presents experimental investigations which made it possible to determine dynamic coefficients of labyrinth over-shroud seal of a model air turbine. The coefficients associate pressure forces with turbine rotor displacement, velocity and acceleration respective to turbine casing (linear model) and play important role in analyzing turbine-set dynamics. The obtained results indicated that involving serious errors can be...
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On the durability of the hydraulic satellite motor working mechanism in overload condition
PublikacjaThe paper presents the newest construction of the hydraulic satellite pump/motor. In this study, the fracture of the hydraulic satellite motor working mechanism is investigated. Factors influencing the durability of satellite working mechanism have been described. The durability of the hydraulic satellite motor working mechanism at a load, corresponding to a pressure of 15 MPa supplied with refined rapeseed oil is very low. Analyses...
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Superconductivity in the niobium-rich compound Nb5Se4
PublikacjaThe niobium rich selenide compound Nb5Se4 was synthesized at ambient pressure by high-temperature solid–state reaction in a sealed Ta tube. Resistivity and heat capacity measurements reveal that this compound is superconducting, with a Tc = 1.85K. The electronic contribution to the specific heat γ and the Debye temperature are found to be 18.1 mJmol−1K−2 and 298 K respectively. The calculated electron-phonon coupling constant λep...
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Human-computer interactions in speech therapy using a blowing interface
PublikacjaIn this paper we present a new human-computer interface for the quantitative measurement of blowing activities. The interface can measure the air flow and air pressure during the blowing activity. The measured values are stored and used to control the state of the graphical objects in the graphical user interface. In speech therapy children will find easier to play attractive therapeutic games than to perform repetitive and tedious,...
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Monitoring of current collectors on the railway line
PublikacjaProper cooperation the current collectors and the overhead line is a pre-requisite for reliable and safe operation of railway transport. Instances of maladjustment and, in some cases, damage to the current collectors, occur between periodic inspections of the rolling stock. In order to detect such anomalies quickly, the test stand was developed, with the aim of monitoring the technical state of the current collectors under operating...
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Influence of the low ambient temperature on the start-up process of hydraulic pumps
PublikacjaStarting hydraulic pumps in low ambient temperatures may cause: decreased hydraulic-mechanical efficiency, larger vibration of hydraulic installation, faster wear and more frequent damage to the elements of pumps, change of material properties of elements, increase of pressure drop. As a result of pressure drop in the suction pipe, large underpressure may be experienced, causing incomplete filling of pump working chambers with...
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Three-dimensional numerical investigation of hybrid nanofluids in chain microchannel under electrohydrodynamic actuator
PublikacjaEnergy efficiency enhancement methods have received considerable attentionwithin the industry and scientific community, owing to the rising concern ofglobal energy sustainability. The present article attempts to scrutinize the effectsof electrohydrodynamics and nanofluids on the rate of heat transfer and fluidflow in the 3-D chain microchannels. Improved heat exchangers (e.g., chainmicrochannel) would have a key role in increasing...
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Combined numerical and experimental approach to determine numerical model of abdominal scaffold
PublikacjaA proper junction of the prosthesis and the abdominal wall is important in successful hernia repair. The number of tacks should be balanced to assure appropriate mesh fixation and not to induce post-operative pain. Numerical simulations help to find this balance. The study is aimed at creating a proper numerical model of a knitted surgical mesh subjected to boundary conditions and load occurring in the abdominal cavity. Continuous,...
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Analysis of the Heating Process of Hydraulic Motors during Start-Up in Thermal Shock Conditions
PublikacjaConditions that prevail during harsh winters and hot summers pose a serious challenge for machine designers building devices suitable for operation in extreme weather. It is essential for the designers and the users to define the principles and conditions for the safe operation of machines and devices with hydraulic drive in low ambient temperatures. Bearing in mind the above, the author tested the hydraulic motors in thermal shock...
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Study of Non-Newtonian biomagnetic blood flow in a stenosed bifurcated artery having elastic walls
PublikacjaFluid structure interaction (FSI) gained attention of researchers and scientist due to its applications in science felds like biomedical engineering, mechanical engineering etc. One of the major application in FSI is to study elastic wall behavior of stenotic arteries. In this paper we discussed an incompressible Non-Newtonian blood fow analysis in an elastic bifurcated artery. A magnetic feld is applied along x direction. For...
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BADANIE EFEKTYWNOŚCI WYKRYWANIA ANOMALII PROCESOWYCH W DZIAŁANIU TURBINY PAROWEJ ELEKTROWNI JĄDROWEJ PRZY POMOCY METOD WIELOWYMIAROWEJ ANALIZY STATYSTYCZNEJ
PublikacjaW artykule przedstawiono analizę możliwości wykrywania anomalii procesowych w działaniu turbiny parowej elektrowni jądrowej przy pomocy metod wielowymiarowej analizy statystycznej. Zasymulowano symptomy dwóch rodzajów uszkodzeń turbiny parowej tj. uderzenie wodne oraz, wyciek pary z zaworu części niskoprężnej. Jako narzędzie diagnostyczne wykorzystano Metodę Składników Podstawowych PCA (z ang. Principal Component Analysis). Jako...
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Outlet Flow Velocity In Circular Culvert
PublikacjaThe outlet flow velocity in the end section of the culvert barrel depends in most cases on the culvert geometry, including the barrel slope, as well as on upstream and downstream channel parameters. Flowing water can create pressure flow or free surface flow in the culvert barrel. In the case of an unsubmerged barrel outlet, the free-surface flow is more frequent than the full flow. Increased velocities can cause channel bed scour...
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Dissociation energies of protonated water clusters
PublikacjaRelative abundances of positively ionized water clusters formed in a low-pressure electrical discharge as function of reduced electric field were obtained by using drift cell and quadrupole mass spectrometer. It was noticed that some clusters say with n = 4 were more abundant than others, at comparable drift conditions. Dissociation energies have been derived from equilibrium conditions for relative clusters abundances. The Hartree-Fock...
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Evaluation of working spaces' technical condition of marine diesel engine on the basis of operation research
PublikacjaThe paper presents the method of evaluation of the technical state of working spaces of a marine diesel engine at the reduced control susceptibility. The method foresees making diagnosis on the basis of the measurements of exhaust gas pressure in the channels connecting engine cylinders with turbocharger's turbine. In the beginning of the article the research objects are characterized i.e. ZVIEZDA main engine of M401 type and the...
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Nonlinear Interaction of Modes in a Planar Flow of a Gas with Viscous and Thermal Attenuation
PublikacjaThe nonlinear interaction of wave and non-wave modes in a gas planar flow are considered. Attention is mainly paid to the case when one sound mode is dominant and excites the counter-propagating sound mode and the entropy mode. The modes are determined by links between perturbations of pressure, density, and fluid velocity. This definition follows from the linear conservation equations in the differential form and thermodynamic...
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Acoustic Hysteresis in Flows with Different Kinds of Relaxation and Attenuation
PublikacjaGraphs in the thermodynamic plane acoustic pressure versus excess acoustic density representing acoustic hysteresis, are considered as indicators of relaxation processes, equilibrium parameters of a flow, and kinds of wave exciters. Some flows with deviation from adiabaticity are examined: the Newtonian flow of a thermocon- ducting gas, the flow of a gas with vibrational relaxation, the flow of liquid electrolyte with a chemical...
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Maritime heritage of small port towns of the Polish coast
PublikacjaThe article describes problems of the gradual disappearance of real maritime heritage in small Polish port cities. The maritime heritage of small port cities was shaped by coastal processes and urban historical conditions what has led to creation of specific types of landscapes. Special architectural objects of the post-port heritage of small ports of the Polish coast are hydrotechnical constructions (i.e. breakwaters, quays),...
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Thermodynamic modeling of combustion process of the internal combustion engines – an overview
PublikacjaThe mathematical description of combustion process in the internal combustion engines is a very difficult task, due to the variety of phenomena that occurring in the engine from the moment when the fuel-air mixture ignites up to the moment when intake and exhaust valves beginning open. Modeling of the combustion process plays an important role in the engine simulation, which allows to predict incylinder pressure during the combustion,...
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HEAT TRANSFER CHARACTERISTICS OF ENHANCED SHELL AND COIL HEAT EXCHANGER
PublikacjaIn the paper authors presented their own constructions of shell and tube heat exchangers with intensified heat transfer. The shell and coils heat exchangers are in common use in heat ventilations and air conditioning systems. Those types of recuperators are quite simple constructions, the low value of pressure drops and good conditions of heat transfer. The present study shows an experimental investigation of the heat transfer...
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Possibilities of radioisotope measuring in control of an unstable solid particles hydrotransport
PublikacjaThe paper presents γ-radiation proposal to control a multiphase flow, independently from circumstances. So this method may be applied even in compound industrial or environmental processes. Moreover in many cases, it is the only method for applications for dense mixture containing coarse angular grains. The constructed equipment allows continuous measurement of density as well as solid phase for both concentration and average velocity....
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Measurement and visualization of sound intensity vector distribution in proximity of acoustic diffusers
PublikacjaIn this work, we would like to present analyses and visualizations of sound intensity distribution measured in proximity of an acoustic diffuser. Such distribution may be used for estimation of basic acoustic parameters of a diffuser. Measurement is performed with the use of a logarithmic sine sweep which allows for the analysis of waves scattered by the diffuser and rejecting the direct sound signal component. Pressure and sound...
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Zastosowanie audytu wewnętrznego u operatorów produkcyjnych w zapobieganiu kryzysom-studium przypadku
PublikacjaGłównym tematem artykułu była analiza badań przeprowadzonych u producenta farb proszkowych przedsiębiorstwa X, w zakresie zastosowania audytu wewnętrznego, jako metody pozwalającej na zapobieganie pojawienia się kryzysu. Właściwa współpraca operatorów produkcyjnych z menedżerami ma kluczowe zna-czenie dla budowy właściwej pozycji audytu wewnętrznego w przedsiębiorstwie X. Brak należytej współpracy na etapie badań, przy braku...
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Seismic damage diagnosis in adjacent steel and RC MRFs considering pounding effects through improved wavelet-based damage-sensitive feature
PublikacjaThis paper aims to propose complex Morlet (cmorfb-fc) wavelet-based refined damage-sensitive feature (rDSF) as a new and more precise damage indicator to diagnose seismic damages in adjacent steel and Reinforced Concrete (RC) Moment Resisting Frames (MRFs) assuming pounding conditions using acceleration responses. The considered structures include 6- and 9-story steel and 4- and 8-story RC benchmark...
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The influence of high temperature wood drying conditions using air-steam mixture on its properties
PublikacjaThe results of properties change of beech wood after drying process are presented. The wood taken to experiments was from northern part of Pomeranian region in Poland. Before the main high temperature drying process using air-steam mixture, wood was initially dried in an open air conditions. The high temperature drying process was conducted at temperature 120oC, humidity 48%, flow rate of drying medium 2.5m/s and atmospheric pressure....
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The use of HPLC-Q-TOF-MS for comprehensive screening of drugs and psychoactive substances in hair samples and several “legal highs” products
PublikacjaNon-targeted screening of drugs present in herbal products, known as “legal high” drugs and in hair as a biological matrix commonly used in toxicological investigations was accomplished with the use of high pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). In total, 25 and 14 therapeutical drugs and psychoactive substances/metabolites were detected in investigated hair samples...
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Structural properties of hypothetical CeBa2Cu3O7 compound from LSDA+DMFT calculations
PublikacjaThe hypothetical stoichiometric CeBa2Cu3O7 (Ce123) compound, which has not been synthesized as a single phase yet, was studied by the density functional theory (DFT). We utilized a method which merges the local spin density approximation (LSDA) with the dynamical mean-field theory (DMFT) to account for the electronic correlations. The LSDA+DMFT calculations were performed in the high-temperature range. The particular emphasis was...
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Diagnostics of commutation unit in satellite pumps and motors
PublikacjaThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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Experimental study of the multi-disc negative brake for a hydraulic motor
PublikacjaThis paper describes the methodology for experimental testing of a multi-disc brake. The construction of this brake was also present. The brake is dedicated to hydraulic motors with a small working volume. Experimental tests were carried out on a brake with plates immersed in oil and, for comparison, tests were carried out on a dry brake. As a result of the tests, the permissible torque (load) that is able to transfer the brake...
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Artificial Neural Network based fatigue life assessment of riveted joints in AA2024 aluminum alloy plates and optimization of riveted joints parameters
PublikacjaThe objective of this paper is to provide the fatigue life of riveted joints in AA2024 aluminum alloy plates and optimization of riveted joints parameters. At first, the fatigue life of the riveted joints in AA2024 aluminum alloy plates is obtained by experimental tests. Then, an artificial neural network is applied to estimate the fatigue life of riveted lap joints based on the number of lateral and longitudinal holes, punch pressure,...
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Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels
PublikacjaThe paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house...
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Air journal bearing utilizing near-field acoustic levitation: stationary shaft case
PublikacjaResults of a study to examine a unique idea of self-levitating journal bearing are presented in this paper. the idea represents a radical departure from the current bearing technology. it utilisesacoustic levitation, which relies on the sound energy radiated by an object supporting a load. acoustic levitation has been demonstrated to support loads of up to 10 kg. in order to support a load theacoustic wave emitted by the radiating...
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A spice equivalent circuit for modeling the performance of dual frequency echo-sounder
PublikacjaThe paper presents novel network equivalent circuit of piezoceramic circular disc transducers that takes into account thickness and radial mode of vibrations. The starting point of the analysis is 4-port description of circular disc element representing the solution of wave equation set in radial and thickness directions. The approximate solution for harmonic case is represented in the form of 4x4 matrix, which is synthesised and...
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The selected effects of high temperature air-steam mixture wood drying
PublikacjaThe results of properties change of beech wood after drying process are presented. The wood taken to experiments was from northern part of Pomeranian region in Poland. Before the main high temperature drying process using air-steam mixture, wood was initially dried in an open air conditions. The high temperature drying process was conducted at temperature 120oC, humidity 48%, flow rate of drying medium 2.5m/s and atmospheric pressure....
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Diagnostics of commutation unit in satellite pumps and motors
PublikacjaThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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MODELLING OF TRANSIENT FLOW IN STORM SEWERS
PublikacjaThe paper focuses on the assessment of second-order explicit numerical scheme for unsteady flows in sewers. In order to simulate the pressurized flow the 'Preissmann slot' concept is implemented. For simulation of the transcritical flow the original and improved McCormack scheme is used. The calculated results are compared with numerical solutions and laboratory measurements published in the technical literature. Moreover, the...
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Measurement of temperature at sliding polymer surface by grindable thermocouples
PublikacjaThis paper is devoted to experimental study of capabilities and limitations of grindable thermocouples as applied to polymer materials sliding on metal. Chromel–alumel and chromel–copel grindable thermocouples have been developed and tested for wide ranges of contact pressure and sliding velocity. The background temperature of the sliding surface can be determined as the lower envelope of the signal from the grindable thermocouple....
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Preparation of porous TiO2 films by means of pulsed laser deposition for photocatalytic applications
PublikacjaIn this work the preparation and structure properties of porous thin films of TiO2 were investigated. The films were produced by means of the pulsed laser deposition technique using laser pulses at 266nm (10Hz) and at fluencies of 1-3.5J/cm2. The process was performed in vacuum using O2 buffer gas and films were deposited on the SiO2 glass or Si substrate. X-ray diffraction (XRD) and Raman analysis of the structure and chemical...
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Selected studies of flow maldistribution in a minichannel plate heat exchanger
PublikacjaAnalysis of the state of-the-art in research of minichannel heat exchangers, especially on the topic of flow maldistribution in multiple channels, has been accomplished. Studies on minichannel plate heat exchanger with 51 parallel minichannels with four hydraulic diameters, i.e., 461 μm, 574 μm, 667 μm, and 750 μm have been presented. Flow at the instance of filling the microchannel with water at low flow rates has been visualized. The...
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EXPERIMENTAL VERIFICATION OF THE METHOD OF FLOW BOILING AND FLOW CONDENSATION HEAT TRANSFER PREDICTION FOR SELECTED FLUIDS
PublikacjaIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of different refrigerants. The experimental data from various research studies from literature were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in- house developed model....