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Search results for: PRESSURE-VVOLUME DIAGRAM
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Advanced Bayesian study on inland navigational risk of remotely controlled autonomous ship
PublicationThe arise of autonomous ships has necessitated the development of new risk assessment techniques and methods. This study proposes a new framework for navigational risk assessment of remotely controlled Maritime Autonomous Surface Ships (MASS). This framework establishes a set of risk influencing factors affecting safety of navigation of a remotely-controlled MASS. Next, model parameters are defined based on the risk factors, and...
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INVESTIGATION OF THE EFFECT OF THE ROCKET'S SUBORBITAL FLIGHT ON BIOFILM, ENZYMES AND BIOSYNTHESIS ON AUTONOMOUS, MODULAR AND SCALABLE PLATFORM FOR CONDUCTING EXPERIMENTS OF AN ASTROBIOTECHNOLOGICAL NATURE
PublicationWith new incentives for human space exploration, biotechnological experiments in orbit became imperative.Answering this need, we build an autonomous, modular, and scalable platform that enables those experiments onrockets. We called it AMBER. The aim of the payload of the R6 suborbital rocket is to perform an experiment tostudy the influence of rocket flights on biofilm, molecular...
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Kwalifikowanie technologii lutowania twardego próżniowego stali austenitycznej zgodnie z wymaganiami przepisów ASME BPVC, sekcja IX
PublicationW artykule przedstawiono procedurę kwalifikowania technologii lutowania twardego w piecu próżniowym na przykładzie elementów ze stali wysokostopowej nierdzewnej austenitycznej łączonych lutem miedzianym z grupy F-No. 105, zgodnie z przepisami ASME Sec. IX, part QB (ASME Boiler and Pressure Vessel Code. Qualification Standard for Welding, Brazing and Fusing; Procedures; Welders; Brazers; and Welding, Brazing and Fusing Operators)....
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Comparative analysis of thermodynamic cycles of selected nuclear ship power plants with high-temperature helium-cooled nuclear reactor
PublicationThis paper presents a comparative analysis of thermodynamic cycles of two ship power plant systems with a high-temperature helium- cooled nuclear reactor. The first of them is a gas system with recuperator , in which classical gas chamber is substituted for a HTGR reactor (High Temperature Gas-cooled Reactor) . The second of the considered cycles is a combined gas-steam system where working medium flux from gas turbine outlet...
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An Experimental and Numerical Analysis of Water Hammer Phenomenon in Slurries
PublicationThe analysis of slurry transportation in pressure pipelines is important both from practical and theoretical point of view. Due to the nature of the medium, the number of problems arising in the course of design, operation, measurements and mathematical modeling is much higher compared to the cases where the flowing liquid is homogeneous. The equations describing the flow are more complex, and higher number of the parameters is...
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POLDER AND CITY: SUSTAINING WATER LANDSCAPES ON AN URBAN EDGE
PublicationThe question investigated in this paper is how to maintain the environmental quality of the polder landscape encompassing the city in the condition of urban pressure on this landscape. On the basis of theoretical approaches, historical surveys and introductory study models new ideas are tested on the case study of Gdansk, a city located in the Vistula River delta in northern Poland. Research shows that the city was created as a...
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Parametric study of fluid flow and heat transfer over louvered fins of air heat pump evaporator
PublicationTwo-dimensional numerical investigations of the fluid flow and heat transfer have been carried out for the laminar flow of the louvered fin-plate heat exchanger, designed to work as an air-source heat pump evap- orator. The transferred heat and the pressure drop predicted by simulation have been compared with the corresponding experimental data taken from the literature. Two dimensional analyses of the louvered fins with varying...
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Management of low-temperature heat source by ORC aided by additional heat source
PublicationThe presented work is aimed at utilisation of waste heat in the manner to produce electricity in ORC installation. Therefore the precondition of the study was to use the waste heat available in the form of a stream of hot water at 90°C. Such low enthalpy heat source is rather insufficient to produce a good quality vapour to feed the ORC turbine. That was the incentive to search for the ways of increasing the temperature of the...
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The Emission and Combustion Characteristics of Marine Diesel Engine with Extreme Throttled of Air or Exhaust Ducts
PublicationPresented paper shows the results of the laboratory tests on the relationship between the extreme throttling of both air intake duct and exhaust gas duct and gaseous emission from the marine engine. The object of research is a laboratory, 4-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests the thermodynamic and exhaust gas emission characteristics...
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Wysokociśnieniowe uszczelnienia ruchu obrotowego wału hydraulicznych maszyn wyporowych
PublicationW artykule przedstawiono wyniki badań mające na celu wytypowanie węzła uszczelniającego wał silnika hydraulicznego zapewniającego najwyższą trwałość przy smarowaniu wodą. Parametry pracy: ciśnienie 2 MPa i minimalna prędkość poślizgu uszczelek 2 m/s. Opisano również nowatorski przyrząd, na którym przeprowadzono pomiary wszystkich parametrów węzła uszczelniającego.
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Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers
PublicationPurpose: The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on...
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Monitoring of fatigue damage development in as-received and exploited 10CrMo9-10 power engineering steel supported by Digital Image Correlation
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The analysis of strain response for as-received and exploited 10H2M power engineering steel subjected to low cycle fatigue in plastic regime
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Effect of high temperature exposure on the fatigue damage development of X10CrMoVNb9-1 steel for power plant pipes
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Impact of laser beam welding on mechanical behaviour of 2.25Cr–1Mo (P22) steel
PublicationThe use of welding processes in the manufacturing and repair of structures intended for the energy industry plays a key role in the guarantee of a continuous supply of fossil fuels, which is the basic condition for ensuring energy security. A square butt joint of 10 mm thick plate of 2.25Cr–1Mo (P22) steel was fabricated by autogenous laser beam welding process and then post-weld heat treatment (PWHT) for two sets of process parameters...
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Microstructure and mechanical properties of a dissimilar metal welded joint of Inconel 617 and P92 steel with Inconel 82 buttering layer for AUSC boiler application
PublicationThe application of the novel dissimilar metal welded (DMW) joint, utilizing Inconel 617 and P92 steel, was showcased in the advanced ultra-supercritical (AUSC) boiler. The work has been performed to investigate the effect of Inconel 82 (ERNiCr-3) buttering layer on microstructure and mechanical properties (high-temperature tensile strength, impact strength and microhardness) of gas tungsten arc welded (GTAW) dissimilar joint between...
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Tribological performance of PTFE-metal binary coatings in rolling/sliding contact
PublicationTribological performance of surface coatings with embedded PTFE reservoirs in rolling/sliding contact is reported. Using two different coating materials and two shapes and patterns of PTFE reservoirs test samples in the form of discs were prepared and tested in a four-ball contact configuration under loads corresponding to nominal contact pressure of 0.5 and 1.0 GPa. It was found that one coating, namely aluminium-bronze with embedded...
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Curves of thermodynamic states in some fluids with dispersion
Publicationvariations in the thermodynamic state of a dispersive medium, caused by sound, are studied. A bubbly liquid and a Maxwell fluid are considered as examples. Curves in the plane of thermodynamic states are plotted. They are in fact pictorial images of linear relations of excess pressure and excess density in the acoustic wave which reflect irreversible attenuation of the sound energy. The curves account for the nonlinear generation...
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Towards high quality ITO coatings: the impact of nitrogen admixture in HiPIMS discharges
PublicationThe paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56 MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore,...
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The application of TD-GC-FID technique for production of matrix-free reference materials
PublicationIn the last few years particular pressure is exerted on finding new analytical methods which would provide real possibilities of monitoring and control of the state of the environment. Intensive development of analytical techniques for measurements of gaseous media and the negative effects of BTX compounds make it necessary to produce new gaseous reference materials. To prepare the appropriate non- matrix reference material thermal...
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The use of Response Surface Methodology for reliability estimation of aluminum silo subjected to wind load
PublicationAn axisymmetric aluminum silo model with a single, standardized geometric imperfection of its lateral surface is considered. The silo is wind – loaded only. The paper is focused on the critical, or limit value of wind pressure, both producing a loss of stability of the silo. This value is affected by vertical coordinate (position) of the imperfection and the angular relation between the imperfection and the wind direction. Reliability...
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Problem of proper decomposition and initialization of acoustic and entropy modes in a gas affected by the mass force
PublicationThe relations connecting perturbations specific for acoustic and entropy modes in an accelerated fluid or in a fluid affected by constant mass force, are derived. They allow to decompose the total vector of perturbations and the overall energy into acoustic and non-acoustic parts uniquely at any instant. In order to do this, three quantities are required, for example total perturbations in entropy, pressure and velocity. The evaluations...
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COMMENTS ON EXISTING ANALYTICAL SOLUTIONS TO THE WAVE-INDUCED CYCLIC RESPONSE OF A POROUS SEABED OF INFINITE THICKNESS
PublicationThis paper deals with the wave-induced cyclic response of a porous seabed (by means of oscillating parameters: pore-fluid pressure, soil displacement components, effective normal stress and shear stress components) due to a surface sinusoidal water-wave propagating over a seabed of infinite thickness. The main existing analytical solutions to the governing problem are critically discussed, pointing out their meaningful errors and...
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Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
PublicationExperimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9 ◦C and hot water of 50 ◦C. The heat exchangers were made from copper tubes with...
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Design and experimental investigations of a cylindrical microjet heat exchanger for waste heat recovery systems
PublicationCompact heat exchangers have more and more applications in many areas, including the HVAC, food and petrochemical industry. This paper describes the development of heat exchanger technology for waste heat recovery (WHR) from a range of processes. Case-study testing shows that the proposed heat exchanger can successfully enhance heat transfer and recover waste heat in a range of applications making them economically, environmentally and...
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Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing
PublicationHydrostatic assistance is a commonly used method to improve limited load carrying ability of tiltingpad thrust bearings during transient states of operation of vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves, etc.), it also requires manufacturing of special recesses/pockets at pad sliding surfaces, into which oil is injected under high pressure. It allows to lift the rotor before start-up...
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URBANIZATION OF METROPOLITAN AREAS – THE IMPORTANCE OF NEW SPATIAL DATA ANALYSIS TOOLS
PublicationNowadays, a rapid development of metropolises is connected with the pressure on urbanizing, which leads to a sharp increase in developed areas as well as urbanized areas. As this trend becomes more dynamic, cities sprawl beyond their administrative boundaries, causing spatial disintegration and hindering sustainable development of a given area. Increased dispersion of residential area results in extensive and chaotic spatial development,...
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Is mesh fixation necessary in laparoendoscopic techniques for M3 inguinal defects? An experimental study.
Publicationrepairs, in case of large direct hernias (M3) mesh fixation is recommended to reduce recurrence risk. Despite lack of highquality evidence, the recommendation was upgraded to strong by expert panel. The authors conducted a research experiment to verify the hypothesis that it is possible to preserve the mesh in the operating field in large direct hernias (M3) without the need to use fixing materials. Method The authors conducted...
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Effects of full displacement pile installation on the stress and deformation state of surrounding soil: review
PublicationSeveral field and model tests have been conducted to investigate the impact of pile installation on bearing capacity. However, little is known about how piles behave during installation, how they interact with the surrounding soil, and how this affects sandy soil properties. This review paper investigates the effect of pile driving on surrounding sandy soil as it compacts sandy soil near to the pile. For this purpose, various related...
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Technical and economic analysis of energy storage in the compressed air technology with low capacity for the production plant
PublicationCompressed air energy storage (CAES) system is a promising technology due to its numerous advantages, including relatively low maintenance cost, a long lifespan and high operational flexibility. This article explores the possibility of designing a CAES power plant as a source of electricity and heat for an existing industrial plant. The study involves the technical analysis of the power plant parameters and the economic analysis...
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Electrical properties of A-site Ca-doped LaNb1-xAsxO4-δ ceramics
PublicationThe electrical properties of A-site Ca-doped LaNbO4 with the addition of As in the B-site, have been investigated. Total, grain- and specific grain boundary electric conductivities in different oxygen partial pressure, and water vapour partial pressure were determined. Additional conductivity measurements were performed in nitrogen, to suppress the possible p-type conductivity, focusing on protonic conductivity. The maximum measured...
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Wpływ kierowcy na opór toczenia samochodu
PublicationW pracy omówiono wpływ zachowań kierowcy na opory toczenia pojazdu w ruchu drogowym. Można tu wyróżnić styl jazdy kierowcy oraz jego dbałość o pojazd. Przedstawiono wzrost oporu toczenia w aspekcie dynamicznego przyspieszania oraz szybkiej jazdy na zakręcie. Przeanalizowano także wpływ na opór toczenia takich czynników jak: ciśnienie w ogumieniu obciążenie promieniowe, zbieżność kół jezdnych samochodu oraz zużycie ogumienia.
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Hałaśliwość silników asynchronicznych – podstawy nowych hipotez
PublicationArtykuł zawiera nowe spojrzenie na hałas emitowany przez silniki asynchroniczne. Poprzez wykonane badania akustyczne z analizami widmowymi określono związki przyczynowo-skutkowe powstawania drgań i hałasu przy zasilaniu sieciowymch i przekształtnikowym. Na podstawie wyznaczonych charakterystyk kierunkowych ciśnienia akustycznego silników sformułowano hipotezę, że rola tarcz łożyskowych w emitowaniu hałasu przez silnik może być...
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Action-reaction based synthesis of acoustic wavefield equations
PublicationThe 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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Effect of Maximal Breath Hold Apnea on Pial Artery Pulsation and Subarachnoid Width in Human
PublicationLittle 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
PublicationThe 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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Two-criteria optimisation problem for ventral hernia repair
PublicationTwo-criteria optimisation problem related to laparoscopic ventral hernia repair is formulated in this paper. An optimal implant from a given set and its orientation is sought. The implant is subjected to kinematic extortions due to a patient’s body movement and intra-abdominal pressure. The first criterion of the optimisation problem deals with the reaction force in the implant fastener, while the deflection of the implant constitutes...
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Dissociation pathways of protonated water clusters
PublicationRelative 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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Comparison of Mathematical Models of Torque Transmitted by Multi-disc Wet Clutch with Experimental Results
PublicationIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
PublicationIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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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
PublicationThe 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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Dynamic effect of the vehicle passing under lightweight footbridge.
PublicationThe 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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Structure redetermination, transport and thermal properties of the YNi3Al9 compound
PublicationSingle 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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Development of an AI-based audiogram classification method for patient referral
PublicationHearing 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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Compact Quasi-Elliptic-Type Inline Waveguide Bandpass Filters With Nonlinear Frequency-Variant Couplings
PublicationThis 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
PublicationPseudo-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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On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages
PublicationThis 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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Monitoring of current collectors on the railway line
PublicationProper 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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On the durability of the hydraulic satellite motor working mechanism in overload condition
PublicationThe 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
PublicationThe 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...