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Search results for: compact heat exchangers
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Doubly miniaturized rat-race hybrid coupler
PublicationTwo complementary miniaturization techniques have beenapplied to reduce the size of a rat-race hybrid coupler: (i) conventional microstrip sections have been replaced with their diminished lowimpedance counterparts as the first step of size reduction and (ii) novel fractal-shaped compact microstrip resonant cells dedicated to efficiently shorten low-impedance transmission line segments have been implemented as the second step of...
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Slow-wave resonant structures in branch-line coupler miniaturization: a case study
PublicationA case study of novel slow-wave resonant structures dedicated to efficient microstrip branch-line coupler size reduction has been presented. A compact 3-dB branch-line coupler has been designed to mimic the performance of its conventional counterpart, simultaneously demonstrating a substantial 88% surface area reduction. The vital usefulness of the approach in the process of microstrip line abbreviation has been experimentally...
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Localization and identyfication of ferromagnetic objects
PublicationA compact ferromagnetic object placed in the earthly magnetic field causes disturbance of this field. This disturbance is associated with magnetization of the object. Ferromagnetic objects have induced and can also have permanent magnetization. In methods of locating and identifying ferromagnetic objects usually is using the model of the dipol moment. Determination of the position and values of the extremes of the magnetic field...
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Periodic expansion in determining minimal sets of Lefschetz periods for Morse–Smale diffeomorphisms
PublicationWe apply the representation of Lefschetz numbers of iterates in the form of periodic expansion to determine the minimal sets of Lefschetz periods of Morse–Smale diffeomorphisms. Applying this approach we present an algorithmic method of finding the family of minimal sets of Lefschetz periods for Ng, a non-orientable compact surfaces without boundary of genus g. We also partially confirm the conjecture of Llibre and Sirvent (J Diff...
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Zagospodarowanie ciepła odpadowego z biogazowych agregatów kogeneracyjnych w oczyszczalni ścieków
PublicationW pracy opisano koncepcję współpracy biogazowych modułów kogeneracyjnych z niskotemperaturowym obiegiem parowym. Proponowana modernizacja pozwoliłaby na wykorzystanie entalpii fizycznej spalin, tym samym zwiększając sprawność urządzeń wytwarzających ciepło i energię elektryczną. Tego typu rozwiązanie umożliwiłoby częściowe pokrycie zapotrzebowania własnego na energię elektryczną, generując oszczędności w przedsiębiorstwie. W artykule...
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Reflectance Measurements and iCone Calorimeter Burning Results of Charcoals Derived from Lake Żabińskie (North-Eastern Poland)
Open Research DataThe dataset presents the results of litter burning experiments using an iCone calorimeter to assess the flammability of the major tree species in the Lake Żabińskie catchment (NE Poland) and links this to the heat release during burning to understand the influence of fire and its effects on ecosystems. Samples of litter from Betula pendula, Pinus sylvestris,...
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SiC coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #B37/#A35
Open Research DataWear tests in sliding friction of SiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, SiC over SiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 3 min.Secimen...
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TiC coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #A39/#B41
Open Research DataWear tests in sliding friction of TiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiC over TiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 3 min.Secimen...
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SiC coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #A35/#B37
Open Research DataWear tests in sliding friction of SiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, SiC over SiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 3 min.Secimen...
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Structural optimization of microjet array cooling system
PublicationThe single phase heat transfer from an upward facing, horizontal copper surface to arrays of impinging water jets was experimentally investigated. Experimental configuration allows for a free-surface unconfined jets flow. Square nozzles 50 × 100 μm arranged in four different geometries were used. Additionally, for the set of two jets array geometry was varied by adjusting the nozzle to nozzle distance. The area averaged heat transfer...
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Inverse determination of sliding surface temperature based on measurements by thermocouples with account of their thermal inertia
PublicationThis study developed an inverse heat conduction algorithm to determine temperature at a sliding surface taking account of thermocouple thermal inertia. The direct heat conduction problem was solved analytically based on the Laplace integral transform approach. The inverse algorithm was applied to the problem of friction of a brake material against a steel. The experiments were conducted on a pin-on-disc tribometer for three short-time...
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The effect of cable duct diameter on the ampacity of high-voltage power cables
PublicationThe ampacity of power cables depends, among others, on the conditions of heat dissipation from the cable to the environment. Cables are usually laid directly in the ground, but in some sections, they may be placed in ducts, which adversely affects the ampacity of the cable line. The paper presents heat transfer phenomena for cables installed in pipe-type ducts filled with air. The effect of cable duct diameter on this ampacity...
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ImBeing Towards Intelligent Micro-Bearings – Tribological Aspects
ProjectsProject realized in Department of Control and Power Engineering
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Effect of annealing temperature on slurry erosion resistance of ferritic X10CrAlSi18 steel
PublicationIn the present work, the slurry erosion tests were carried out to investigate the influence of heat treatment on slurry erosion process of ferritic X10CrAlSi18 stainless steel using a slurry pot test rig. X10CrAlSi18 stainless steel was tested in as-received condition and after annealing at three different temperatures: 600°C, 800°C and 1000°C. Degradation of materials due to slurry erosion depends on many factors connected with...
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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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Structural and luminescent study of TeO2-BaO-Bi2O3-Ag glass system doped with Eu3+ and Dy3+ for possible color-tunable phosphor application
PublicationTellurite glass systems of 73TeO2-4BaO-3Bi2O3-1Ag:xEu2O3-(2-x)Dy2O3 (where x = 0.5, 1, 1.5, 2 in molar ratio) composition have been successfully synthesized. In order to acquire Ag nanoparticles, materials have been heat treated at 350 °C in the air atmosphere. Structural properties of obtained samples were evaluated with various techniques. X-Ray Diffraction (XRD) measurements indicated that obtained materials are amorphous in...
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Selected design and construction aspects of supercritical steam generators for high temperature reactors = Wybrane aspekty konstrukcyjne i projektowe generatorów pary nadkrytycznej ogrzewanych z reaktorów wysokotemperaturowych
PublicationW artykule zaprezentowano uwarunkowania projektowe i konstrukcyjne nadkrytycznego generatora pary (jednoprzepływowego) wykorzystującego do ogrzewania hel z reaktorów HTR i VHTR. Wymiennik helikoidalny jest preferowany dla zwiększenia wymiany ciepła i zwartości. Badano własności czynników wymieniających ciepło z parą w obszarach przy- i nadkrytycznych. Analizowano korelacje, aby wybrać najbardziej wiarygodne. Przedyskutowano najbardziej...
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The behavioural model of graphene field-effect transistor
PublicationThe behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-states characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations...
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A commercial gas boiler fitted with the ORC module as perspective solution for households
PublicationIn this paper the applicability of the commercial gas boiler (De Dietrich DTG X23N) coupled with the laboratory prototype micro ORC setup was experimentally studied. The main objective was to determine the working fluid capability to obtain required temperatures of vapour prior to the turbine, attainable heat rates and efficiencies of the whole system. The boiler thermal power was 25 kW. Tests were carried out with a single stage...
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Entropy of water calculated from harmonic approximation: estimation of the accuracy of method
PublicationSome molecular dynamics simulations were performed for liquid TIP4P and SPC water at a constant density (1.00 g/cm(3)) and within the temperature range of 5-90 degrees C. By using harmonic approximation, both the entropy of water S-H and the specific heat c(v) were calculated, and the results were compared to literature data. It was found that harmonic approximation overestimates absolute entropy of TIP4P water by 5.6 J/mol K (similar...