Search
displaying 1000 best results Help
Search results for: hyperbolic heat conduction
-
GPR investigation of the strengthening system of a historic masonry tower
PublicationIn this paper the condition assessment of the strengthening system of a masonry tower was carried out by the GPR method. The study provided unique experimental data acquired during measurements of the reinforced concrete frame embedded in masonry walls. Conducted numerical and experimental investigations were focused on the phenomenon of the diffraction-refraction scattering of the electromagnetic energy. A hyperbola resulting...
-
Photophysics of a Ruthenium 4H-Imidazole Panchromatic Dye in Interaction with Titanium Dioxide
PublicationThe photophysics of bis(4,4′-di-tert-butyl-2,2′-bipyridine-κ2N,N′)[2-(4-carboxyphenyl)-4,5-bis(p-tolylimino-κN)imidazolato]ruthenium(II) hexafluorophosphate is investigated, both in solution and attached to a nanocrystalline TiO2 film. The studied substitution pattern of the 4H-imidazole ligand is observed to block a photoinduced structural reorganization pathway within the 4H-imidazole ligand that has been previously investigated....
-
About definition of modes and magnetosonic heating in a plasma’s flow: Especial cases of perpendicular and nearly perpendicular wave vector and magnetic field
PublicationDynamics of hydrodynamic perturbations in a plasma depend strongly on an angle between the wave vector and equilibrium straight magnetic field. The case of perpendicular propagation is especial. There are only two (fast) magnetosonic modes since two (slow) ones degenerate into the stationary one with zero speed of propagation. This demands individual definition of wave modes by the links of hydrodynamic relations. These links are...
-
High-conducting Bi4V2-xFexO11-δ ceramics containing Fe2O3 nanocrystals: Structure and properties
PublicationThe topography, structure, thermal, magnetic, and electrical properties of Bi4V2-xFexO11-δ ceramics substituted with x = 0.5 and 0.7 Fe were studied. The microscope analysis showed the presence of iron-rich nanocrystals formed on the Bi-Fe-V-O grains. The X-ray diffraction studies confirmed that grains are built mostly of tetragonal Bi4V1.5Fe0.5O10.5 phase. Thermal properties analysis showed an order-disorder type γ ↔ γʹ phase...
-
Analytical Estimation of Power Losses in a Dual Active Bridge Converter Controlled with a Single-Phase Shift Switching Scheme
PublicationMicro-grid solutions around the world rely on the operation of DC/DC power conver- sion systems. The most commonly used solution for these topologies is the use of a dual active bridge (DAB) converter. Increasing the efficiency and reliability of this system contributes to the improvement in the stability of the entire microgrid. This paper discussed an analytical method of energy efficiency and power loss estimation in a single...
-
Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet
PublicationThe long-range order of noncoplanar magnetic textures with scalar spin chirality (SSC) can couple to conduction electrons to produce an additional (termed geometrical or topological) Hall effect. One such example is the Hall effect in the skyrmion lattice state with quantized SSC. An alternative route to attain a finite SSC is via the spin canting caused by thermal fluctuations in the vicinity of the ferromagnetic ordering transition....
-
The Use of Liquid Crystal Thermography in Selected Technical and Medical Applications—Recent Development
PublicationThermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. Thin coatings of TLC at surfaces are utilized to obtain detailed temperature distributions and heat transfer rates for steady or transient processes. Liquid crystals also can be used to make the temperature and velocity fields in liquids visible...
-
Design analysis of combined gas-vapour micro power plant with 30 kW air turbine
PublicationThe article presents basic results of the design analysis of a combined gas-vapour micro power plant with a waste-heat boiler without exhaust reheat, working in the vapour section in the Organic Rankine Cycle (ORC) system. The analysis concerned working media most frequently used in those types of power plants and planned to be used in future. The object of the analysis was a micro power plant with a 30 kW gas (air) turbine for...
-
Thermodynamic Characteristics of Phenacetin in Solid State and Saturated Solutions in Several Neat and Binary Solvents
PublicationThe thermodynamic properties of phenacetin in solid state and in saturated conditions in neat and binary solvents were characterized based on differential scanning calorimetry and spectroscopic solubility measurements. The temperature-related heat capacity values measured for both the solid and melt states were provided and used for precise determination of the values for ideal solubility, fusion thermodynamic functions, and...
-
Design analysis of combined gas-vapour micro power plant with 30 kW air turbine
PublicationThe article presents basic results of the design analysis of a combined gas-vapour micro power plant with a waste-heat boiler without exhaust reheat, working in the vapour section in the Organic Rankine Cycle (ORC) system. The analysis concerned working media most frequently used in those types of power plants and planned to be used in future. The object of the analysis was a micro power plant with a 30 kW gas (air) turbine for...
-
Flame retardant epoxy/halloysite nanotubes nanocomposite coatings: Exploring low-concentration threshold for flammability compared to expandable graphite as superior fire retardant
PublicationEpoxy nanocomposites containing halloysite nanotubes (HNTs) were developed and their low-concentration thresholds for thermal stability and flame retardancy were compared with that of epoxy system containing expandable graphite (EG), as a reference with superior flame retardancy. The effects of HNTs and EG on the peak of Heat Release Rate (pHRR), Total Heat Release (THR), and Time-To-Ignition (TTI) of the prepared samples were...
-
Effect of Electron Beam Power Density on the Structure of Titanium Under Non-Vacuum Electron-Beam Treatment
Publication -
Experimental investigations of natural convection from circular plates at variable inclination
PublicationW pracy przedstawiono wyniki badań eksperymentalnych oraz bezwymiarową korelację liczb kryterialnych dla konwekcyjnej wymiany ciepła od izotermicznej płyty kołowej skierowanej ku górze dla różnych kątów pochylenia (od poziomej do pionowej) w szerokim zakresie wartości liczb Rayleigha. Badania przeprowadzono w wodzie dla płyty kołowej o średnicy 0,07 m. Celem pracy było określenie wpływu kąta pochylenia płyty na wartość liczby Nusselta.
-
Assessment of the Thermal Effectiveness of Mineral Warmers for Protective Gloves Used in Cold Environments
Publication -
Analytical method of determining dynamic properties of thermocouples used in measurements of quick – changing temperatures of exhaust gases in marine diesel engines
PublicationThe article presents selected issues of mathematical modeling of heat exchange between the thermocouple and the exhaust gas flowing them, in unsteady conditions. On the way of energy balancing consideration of thermodynamic processes developed differential equations describing the dynamic properties for three versions of the design sheathed thermocouples: with weld isolated from the sheath, with weld welded the sheath and with...
-
Analysing selection of low-temperature medium for cogeneration micro power plant
PublicationThe article analyses the ORC system working with dry and wet low-boiling media which are most frequently used in installations of this type. Two types of cycles were examined, which were the cycle with heat regeneration for dry media: fc72, hfe7100, R227ea, R245fa, R423a and R600a, and the cycle without heat regeneration for wet media: R11, R12, R134a, R718 and 507a. The calculations were performed for the assumed required thermal...
-
WSPÓŁPRACA BLOKU GAZOWO-PAROWEGO Z OBIEGIEM ORC = Combinded power plant in cooperation with ORC
PublicationIn the paper presented is the idea of a combined gas and steam power plant cooperation with a low temperature organic Rankine cycle ORC unit. Considerations presented in the paper are accomplished for the Gorzów CHP. The intention of present analysis is heat recovery of low temperature energy and its further use in ORC cycle in order to produce electricity, without increase in fuel consumption. Waste energy is recovered from the...
-
Analysing selection of low-temperature medium for cogeneration micro power plant
PublicationThe article analyses the ORC system working with dry and wet low-boiling media which are most frequently used in installations of this type. Two types of cycles were examined, which were the cycle with heat regeneration for dry media: fc72, hfe7100, R227ea, R245fa, R423a and R600a, and the cycle without heat regeneration for wet media: R11, R12, R134a, R718 and 507a. The calculations were performed for the assumed required thermal...
-
CO2 capture using steam ejector condenser under electro hydrodynamic actuator with non-condensable gas and cyclone separator: A numerical study
PublicationThe concept for condensation of steam and CO2 separation in a negative CO2 emission gas power plant involves the utilization of a steam ejector condenser (SEC) for direct-contact condensation of vapor with inert gas (CO2) on a spray of subcooled liquid, integrated with a separator to produce pure CO2. Due to the increasing diffusion resistance and reduced convective heat transfer between the steam and subcooled water phases...
-
Enzymatic cross-linking of β-lactoglobulin in solution and at air–water interface: Structural constraints
PublicationEffective and controlled use of cross-linking enzymes in structure engineering of food systems depends on characterization of the favorable conditions for enzyme-substrate complex and the limiting factors for the desired modification. In this respect, we analyzed the susceptibility of bovine β-lactoglobulin (BLG) to enzymatic cross-linking by Trichoderma reesei tyrosinase (TrTyr) and transglutaminase (TG). Changes in BLG molecular...
-
Crystal structure and low-energy Einstein mode in ErV2Al20 intermetallic cage compound
PublicationSingle crystals of a new ternary aluminide ErV2Al20 were grown using a self-flux method. The crystal structure was determined by powder X-ray diffraction measurements and Rietveld refinement, and physical properties were studied by means of electrical resistivity, magnetic susceptibility and specific heat measurements. These measurements reveal that ErV2Al20 is a Curie-Weiss paramagnet down to 1.95 K with an effective magnetic...
-
Experimental study of pressure rise at the evaporator of capillary pumped loop with acetone and water as working fluids
PublicationIn this work studied is the possibility of fluid pumping using capillary forces in the capillary pumped loop. Experimental and theoretical studies have been performed to understand the phenomena associated with heat transfer in porous structure of the evaporator. The capillary effect was studied during operation of two different capillary porous structures with two different working fluids, namely water and acetone. The results...
-
THERMAL ANALYSIS AND DESIGN OF HYBRID MICROCHANNEL-MICROJET TEST PROBE
PublicationThe paper presents the numerical investigation of a microjet- microchannel cooling module. In which microjets of water are impinging into the microchannels and forming a liquid film on the impingement surface. Applied technology takes benefits from two very attractive heat removal techniques. When lminar jets are impinging on the surface have a very high kinetic energy at the stagnation point, also in microchannels boundary layer...
-
Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublicationThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
-
Analysis of the possibility of increasing thermal-electric energy conversion ratio in CHP units based on micro gas turbine
PublicationThe aim of this paper is to analyze the possibility of increasing thermal energy to electricity conversion efficiency in combined heat and power (CHP) units based on micro gas turbine during low heat demand periods. At the beginning sustainable development postulates under power engineering are explained. Next micro CHP as part of distributed generation idea is presented. The main part of the article is based on results of thermodynamic...
-
SELECTED COMBINED POWER SYSTEMS CONSISTED OF SELFIGNITION ENGINE AND STEAM TURBINE
PublicationThis paper presents optimization of selected combined diesel engine-steam turbine systems. Two systems: the system combined with waste heat one-pressure boiler only and its version containing additionally low-pressure boiler proper feeding degasifier and the system of two-pressure cycle, were taken into considerations. Their surplus values of power output and efficiency associated with utilization of waste heat contained in piston...
-
The σ-phase superconductors Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9
PublicationWe show that the previously unreported ternary σ phases Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9 are both superconductors with Tc values of approximately 1.9 K. The superconducting transitions were characterized through temperature-dependent magnetic susceptibility, electrical resistance, and specific heat measurements. The Sommerfeld constants, γ, for Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9 are 89(1) mJ mol-f.u.−1K−2 and 86(1) mJ mol-f.u.−1K−2...
-
ImBeing Towards Intelligent Micro-Bearings – Tribological Aspects
ProjectsProject realized in Department of Control and Power Engineering
-
An energetic analysis of a gas turbine with regenerative heating using turbine extraction at intermediate pressure - Brayton cycle advanced according to Szewalski's idea
PublicationIn this paper, a modification of a simple gas turbine into the Brayton cycle with regenerative heating, using turbine extraction at intermediate pressure, is presented. The main concept of the retrofitting is based on the transfer of heat from the turbine exhaust gases to the air entering the combustion chamber. The extracted gas transfers heat to air via the divided regenerative heat exchanger and after that is compressed and...
-
Experimental research on helical coil biomass boiler with oil as a heating fluid
PublicationThis paper presents an experimental research of helical coil biomass boiler with thermal oil heating agent. Heat exchanger consists of two coaxial helical coils swept by the flue gases. The burner is a single vertical retort connected to the fuel tank (wooden pellets). The boiler is a part of micro-power plant in which the heat from the boiler is exchanged with low-boiling HFE7100 to produce steam for a custom steam turbine. The...
-
Determination of pressure drop in flow condensation of HFE7000 in minichannels with account of non-adiabatic effects
PublicationFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation, however such method has yet to be suggested. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear...
-
Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements
PublicationThe paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically...
-
Superconductivity in LiGa2Ir Heusler type compound with VEC = 16
PublicationPolycrystalline LiGa2Ir has been prepared by a solid state reaction method. A Rietveld refnement of powder x-ray difraction data confrms a previously reported Heusler-type crystal structure (space group Fm-3m, No. 225) with lattice parameter a= 6.0322(1) Å. The normal and superconducting state properties were studied by magnetic susceptibility, heat capacity, and electrical resistivity techniques. A bulk superconductivity with...
-
On the generalized model of shell structures with functional cross-sections
PublicationIn the present study, a single general formulation has been presented for the analysis of various shell-shaped structures. The proposed model is comprehensive and a variety of theories can be used based on it. The cross-section of the shell structure can be arbitrarily analyzed with the presented equations. In other words, various types of shell structures, including cylindrical, conical, spherical, elliptical, hyperbolic, parabolic,...
-
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...
-
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,...
-
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...
-
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...
-
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...
-
MULTI-CRITERIA INVESTMENT DECISION SUPPORT MODEL USING FUZZY ANALYTIC HIERARCHY PROCESS (F-AHP) METHOD FOR POWER INDUSTRY
PublicationIn this paper, the comparative analysis of two wind farm construction projects was presented. This particular type of analysis is commonly applied before purchasing investment project being in a planning phase by a company interested in its development. Conduction of this type of analysis is prompted by the necessity to take into consideration the requirements of Polish legislation. Comparison of wind farm construction projects...
-
Electron mobility variance in semiconductors: the variance approach
PublicationPraca przedstawia nowe podejście da analizy zjawisk losowych w półprzewodnikach. Uwzględnia kilka mechanizmów zjawisk fluktuacji ruchliwości w półprzewodnikach, prowadzących do powstawamai składowej szumów typu 1/f, dominujących w zakresie małych czetotliwości. Przedstawia analizę sposobu wyznaczenia stałej Hooge'a określającej intensywność szumów typu 1/f.The statistical non-triviality of current carrier mobility fluctuations...
-
Determination of ionic conductivity in the Bi-Si-O and Pb-Si-O glasses
PublicationImpedance spectroscopy measurements in various gas atmospheres were carried out in order to explain the doubts about the type of carriers and the mechanism of electrical conductivity in Bi-Si-O and Pb-Si-O glasses. In bismuth silicate glass, a typical ionic conductivity with oxygen ions as charge carriers was observed. The level of electrical conductivity of the glass at 400 °C was 5 × 10−8 S·cm−1 , with the activation energy of...
-
Hebb–Wagner polarization method for determining the oxygen ion conductivity in barium cerate-zirconate
PublicationIn this work, the partial conductivity of oxygen ions in BaCe0.6Zr0.2Y0.2O3 was studied at different temperatures and water partial pressures. For this purpose, a modified DC Hebb–Wagner polarization method with an electrode blocking for protons and electrons was used. A new type of measuring cell as well as a suitable calculation model were proposed for the determination of partial oxygen ionic conductivity in materials with three...
-
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...
-
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...
-
OPTIMIZATION OF ENERGY CONVERSION IN GOLD NANOPARTICLES IRRADIATED BY LIGHT FOR SUSTAINABLE ENERGY APPLICATIONED BY LIGHT FOR SUSTAINABLE ENERGY APPLICATION
PublicationThis study investigates the optimization of light-to-heat conversion in gold nanoparticles under irradiation by continuous- and pulsed-wave laser sources. The conversion process relies on the absorption of electromagnetic energy and the subsequent generation of heat, a phenomenon that is integral to a variety of applications. The photothermal conversion model is based on the Rayleigh-Drude approximation, facilitating predictions...
-
Aimad Koulali dr
People -
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...
-
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...
-
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...