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Search results for: INTENSIFICATION OF HEAT EXCHANGE
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Thermal energy storage using stearic acid as PCM material
PublicationThis work presents an experimental study of thermal energy storage by use of PCM. The aim of the study was to establish the influence of different inlet temperature of heat transfer fluid (HTF) and different Reynolds number of HTF on intensity of charging process. The PCM used in this study was stearic acid and water was used as HTF. A copper helical coil mounted in cylindrical container served as a heat transfer surface.
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Pin Angle Thermal Effects on Friction Stir Welding of AA5058 Aluminum Alloy: CFD Simulation and Experimental Validation
PublicationThe friction stir welding (FSW) of tool pin geometry plays a critical role in the final properties of the produced joint. The tool pin geometry directly affects the generation of heat and the flow of internal materials during the FSW process. The effects of the FSW tool pin angle on heat generation and internal flow have not been quantitatively investigated in detail. In this manuscript, a validated Computational Fluid Dynamic...
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Flow boiling of R1233zd(E) in a 3 mm vertical tube at moderate and high reduced pressures
PublicationThe results of flow boiling of R1233zd(E) in a 3 mm vertical stainless steel tube are presented at moderate and high saturation temperatures. Integral flow characteristics in the form of pressure drop and heat transfer coefficient are discussed for saturation temperatures ranging from 115 to 145 °C (corresponding reduced pressures from 0.2 to 0.7), mass velocity of 800 kg/m2s and heat flux of 20 kW/m2. All of the obtained heat...
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Experimental validation of pressure drop models during flow boiling of R134a – effect of flow acceleration and entrainment
PublicationA crucial step to assure proficient work of power and process apparatus is their proper design. A wide array of those devices operates within boiling or condensation of the working fluid to benefit from high heat transfer rates. Two-phase flows are associated with high heat transfer coefficients because of the latent heat of evaporation and high turbulence level between the liquid and the solid surface. Predicting heat transfer...
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Thermal conductivity of M0-M100 specimens
Open Research DataThermal conductivity and volumetric heat capacity values of M0, M20, M40, M60, M80, M100 samples
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Dilatometry results of SrTi0.50Fe0.50O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.50Fe0.50O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.50Fe0.50O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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Dilatometry results of SrTi0.65Fe0.35O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.65Fe0.35O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.65Fe0.35O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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Dilatometry results of SrTi0.30Fe0.70O3-d powder
Open Research DataThis dataset contains results of dilatometry measurements of SrTi0.30Fe0.70O3-d powder. The investigation of the linear thermal expansion was carried out using a Netzsch DIL402 dilatometer. The SrTi0.30Fe0.70O3-d powder was formed into cylinders and heat up to 1100 °C with a heating rate of 5 °C min−1, dwelled for 15 min, and then cooled at a rate of...
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Przegląd rodzajów chiralnych faz stacjonarnych oraz możliwości ich zastosowań w chromatografii cieczowej
PublicationChromatograficzne rozdzielanie związków optycznie czynnych ma ogromne znaczenie nie tylko w przemyśle farmaceutycznym, ale i agrochemicznym, a także w badaniach naukowych różnego rodzaju. W niniejszym opracowaniu scharakteryzowano komercyjnie dostępne chiralne fazy stacjonarne na bazie, cyklodekstryn, polisacharydów, makrocyklicznych antybiotyków, eterów koronowych, a także fazy proteinowe, ligandowymienne, jonowymienne oraz fazy...
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Alternative cogeneration thermodynamic cycles for domestic ORC
PublicationThe Organic Flash Cycle (OFC) is suggested as a vapor power cycle that could potentially improve the efficiency of utilization of the heat source. Low and medium temperature finite thermal sources are considered in the cycle. Additionally the OFC’s aim is to reduce temperature difference during heat addition. The study examines 2 different fluids. Comparisons are drawn between the OFC and an optimized basic Organic Rankine Cycle...
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Structural change of carbon supported Pt nanocatalyst subjected to a step-like potential cycling in PEM FC
PublicationIn this paper we present detailed X-ray absorption fine structure (XAFS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations of the changes in the local geometric and electronic structure of Pt nanoparticles used as a cathode catalyst in proton exchange membrane fuel cell (PEMFC), working under controlled potential cycling conditions.
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Share of gross value added generated by enterprises in GDP
Open Research DataAfter Poland joined the group of countries associated in the European Union and through participation in numerous economic and political organizations (including the World Trade Organization, OECD), as well as the commencement of trade exchange with virtually all countries of the world, Polish entrepreneurs and managers struggle with completely problems...
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The number of active enterprises in Poland in 1997-2014
Open Research DataAfter Poland joined the group of countries associated in the European Union and through participation in numerous economic and political organizations (including the World Trade Organization, OECD), as well as the commencement of trade exchange with virtually all countries of the world, Polish entrepreneurs and managers struggle with completely problems...
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Income obtained according to particular rates only by taxpayers conducting non-agricultural business activity 2015
Open Research DataTaxation in the form of a lump sum on recorded revenues does not apply to certain types of activity, regardless of their size. We are talking about taxpayers who achieve revenue in whole or in part, among others from on account of running pharmacies, activities in the field of buying and selling foreign exchange values, activities in the field of trade...
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Turbulence models impact on the flow and thermal analyses of jet impingement
PublicationAccurate numerical reconstruction of heat and mass transfer processes in particular applications, such a jet impingement, is difficult to obtain even with the use of modern computational methods. In the proposed paper, the flow and thermal phenomena occurring during single minijet impingement on the flat, concave and convex, heated surfaces were considered. Problem of impingement on non-flat surface, still not common and purely...
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Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop
PublicationThe paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the...
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Domestic ORC micro-CHP combined with a commercial gas boiler
PublicationThe chapter presents the results of experimental studies conducted during the launch of the first in Poland demonstration prototype of the micro ORC coupled to a domestic gas boiler. The accomplished studies indicated the possibility for the ORC module to work with such boiler (autonomous source of heat) with a prototype single-stage axial micro turbine as the expansion machine. Confirmation of that fact has been delineated in...
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Possibility to use engine compression ignition engines in floating power plants marine
PublicationCompression-ignition engines used in ship technology as main propulsion engines are large units reaching even to 50-60 MW. The engines can be used in power industry for electricity generation in a simple or combined steam turbine system in combined heat and power plants. The leading engine in such an arrangement is an internal-combustion piston engine. The main propulsion engines are used in large piston internal-combustion engines...
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Feasibility of combined diesel engine - steam turbine in power station operating in the maritime
PublicationCompression-ignition engines used in ship technology as main propulsion engines are large units reaching even to 50-60 MW. Currently, the efficiency of such engines amounts to 45-50%. With such a large power unit, exhaust gases leaving the engine contain very large quantities of heat available for further treatment. Exhaust gases from the piston engine contain about 25% of the heat supplied to the engine in the fuel. Using the...
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The effect of heating and fermenting on antioxidant properties of white cabbage
PublicationIt is widely believed that natural antioxidants found in food are significantly lost during processing. Nevertheless, it was recently demonstrated that processed fruits and vegetables may retain their antioxidant activity. In the present work, the changes in the overall antioxidant properties as a consequence of fermentation of cabbage and/or heat treatment of cabbage juices and extracts were studied. Fermentation processes as...
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Application of Thermo-chemical Technologies for Conversion of Associated Gas in Diesel-Gas Turbine Installations for Oil and Gas Floating Units
PublicationThe paper considers the issue of thermo-chemical recovery of engine’s waste heat and its further use for steam conversion of the associated gas for oil and gas floating units. The characteristics of the associated gas are presented, and problems of its application in dual-fuel medium-speed internal combustion engines are discussed. Various variants of combined diesel-gas turbine power plant with thermo-chemical heat recovery are...
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Kinetics of Intermetallic Phase Precipitation in Manual Metal Arc Welded Duplex Stainless Steels
PublicationThe article presents the influence of heat treatment on the kinetics of transformations in lean duplex LDX2101 steel and a weld made of standard duplex 2209 material, which was welded by manual metal arc welding. Changes in the microstructure, hardness, and magnetic phase content were analyzed after heat treatment was conducted at a temperature of 800 °C for a period ranging from 15 to 1440 min. Light and scanning microscopy, Vickers...
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A pore-scale thermo–hydro-mechanical model for particulate systems
PublicationA pore scale numerical method dedicated to the simulation of heat transfer and associated thermo–hydro-mechanical couplings in granular media is described. The proposed thermo–hydro-mechanical approach builds on an existing hydromechanical model that employs the discrete element method for simulating the mechanical behavior of dense sphere packings and combines it with the finite volume method for simulating pore space fluid flow...
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Seashore sediment and water chemistry at the Admiralty Bay (King George Island, Maritime Antarctica) – geochemical analysis and correlations between the concentrations of chemical species
PublicationThis study covers water and sediment chemical characteristics by the western shore of Admiralty Bay (King George Island, Antarctica) in 2016. Chemical processes between sediment and water have been described based on the determination of ions, metals, non-metals, and TOC concentrations. Rock weathering is an important source of Fe, Ni, Co, Al in the seashore area. The PCA shows the impact of acidification in the release metals...
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Structural Heterogeneity Between EU15 and 12 New EU Members – the Obstacle to Lisbon Strategy Implementation
PublicationThe aim of this article is to identify diversity between the EU-15 and the New Members in their implementation of the Lisbon Strategy in the period 2000-2010. By analyzing a set of structural indicators, we aim to fill a gap in the literature: a lack of publications providing complex evaluation of the implementation of the Lisbon Strategy using measurable indicators. Given their suitability for international comparisons, we use...
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GVC involvement and the gender wage gap: Micro -evidence on European countries
PublicationWe examine linkages between involvement in global value chains (GVCs) and gender wage inequalities. We use merged data from Structure of Earnings Survey and the World Input Output Database covering 18 European countries. We employ information on employees’ personal and company characteristics and a sectoral involvement in GVCs. In general, the wages of workers from sectors more involved in GVCs are lower. However, the relationship...
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Acetate-Induced Disassembly of Spherical Iron Oxide Nanoparticle Clusters into Monodispersed Core−Shell Structures upon Nanoemulsion Fusion
PublicationIt has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA−IONPs) with the etyltrimethylammonium (CTA+) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange...
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The Metal-Free Regioselective Deuteration of 2-Methylquinolin-8-ol and 2,5-Dimethylquinolin-8-ol, Spectroscopic and Computational Studies
PublicationAbstract: Aim and Background: Introducing deuterium to a molecule is of interest to a wide variety of research, including investigation of reaction mechanisms or kinetics, analysis of drug metabolism, structural elucidation of molecules, and syntheses of isotopically labeled materials used for NMR spectroscopy and medicinal research. Objective: The transition-metal-free regioselective deuteration of 2-methylquinolin-8-ol...
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Chapter 4. Electricity generation from glucose microbial fuel cell
PublicationThe microbial fuel cell was constructed to generate electricity with simultaneous digestion of a glucose fuel by a bacterial biofilm. The decomposition of glucose resulted in releasing of electrons to an anode and to production of some by-products, e.g. metane or organic acids. It was found that maximum electric power density strongly depended on the proton transport through the proton exchange membrane seperating the anolyte and...
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BET of TiO2 heated at 400-600 C degrees
Open Research DataThese data refer to the results of BET surface area of TiO2, which was treated firstly in autoclave at 150 C degrees for 1h (sample marked as A150), then was further heat treated in Ar or H2 at 400-600 C degrees. As a raw material TiO2 was used, which was a semiproduct from the industrial production of titania white by sulphur method. The raw material...
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The influence of thermal treatment on electrocatalytic properties of Mn-Co nanofilms on nickel foam toward oxygen evolution reaction activity
PublicationThis work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 C and 600 C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after...
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Mechanical and structural behavior of high-strength low-alloy steel pad welded by underwater wet welding conditions
PublicationThe aim of the paper was to determine the metallurgical and mechanical behaviors of a high-strength low-alloy (HSLA) steel pad-welded specimen used in the structures of industrial and naval parts. Then to predict the metallurgical consequences (nature of the phases present) and the mechanical properties (hardness and impact strength) of the pad-welded steel obtained by underwater wet welding with different heat input values. The...
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Effects of Noncontact Shoulder Tool Velocities on Friction Stir Joining of Polyamide 6 (PA6)
PublicationIn this study, the effects of the traverse and rotational velocities of the noncontact shoulder tool on the heat generation and heated flux during the friction stir joining of high-density polyamide 6 (PA6) polymer were investigated. The computational fluid dynamics (CFD) method was employed to simulate the thermomechanical phenomena during the friction stir joining (FSJ) process of PA6. A developed model was used to consider the...
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Koncepcja społecznej odpowiedzialności biznesu w usługach ubezpieczeniowych
PublicationCelem artykułu jest przedstawienie koncepcji społecznej odpowiedzialności biznesu (CSR) w usługach ubezpieczeniowych. Zidentyfikowano w tym celu podstawowe oczekiwania interesariuszy oraz najważniejsze obszary zastosowania CSR w instytucjach ubezpieczeniowych. Zaprezentowano również podstawowy związek pomiędzy działaniami społecznie odpowiedzialnymi realizowanymi przez instytucje ubezpieczeniowe a ich wizerunkiem. Na podstawie...
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The influence of solution annealing temperature on the properties of Lean Duplex 2101 welded joints in tubes
PublicationThe article presents a technology of TIG longitudinal welding without filler material (142) of heat exchanger tubes made of Lean Duplex 2101. The results of studies on the effect of heat treatment (solution annealing) on tensile strength, plasticity, delta ferrite and the structure of smooth tubes are shown. It was found, that the change in solution annealing temperature across the tested range has an impact on mechanical properties...
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The experimental results of sorption cycles
Open Research DataExperimental studies of sorption cycles were carried out using a prototype research stand, which is a laboratory-scale model of an adsorption chiller. The Intensified Heat Transfer Adsorption Bed (IHTAB) reactor is adapted to the analysis and optimization of various parameters of adsorption systems, e.g., constructions and compositions of adsorption...
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Comparative study of flow condensation in conventional and small diameter tubes
PublicationFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena, however their description with a single correlation has yet to be suggested. In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where the bubble generation is not present. Similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such...
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Storing thermal energy from solar collectors for the needs of a detached house
PublicationThis work evaluates the possibility of meeting a single familu household's need for hot water and heat year round, using solar collectors as the sole energy sourse. The main flaw of energetic systems based on solar energy is that the energy supply is usually insufficient in winter, when it is most needed. This work is going to show thatm for a house surface of 150 m2 and base dimension of 10x10m, it is possible to supply sufficient...
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Control of a vapour microturbine set in cogeneration applications
PublicationSystems with microturbines are implemented for local generation of heat and electricity. This paper presents the analysis of control concepts for a vapour microturbine set with a generator with permanent magnets, intended to work in small heat and power plants. Control system variants differed by the selection of controlled signals and set parameters. Possible ways of control were discussed and compared with experimentally determined...
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Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation
PublicationOne of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW...
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Low-Power WSN System for Honey Bee Monitoring
PublicationThe paper presents a universal low-power system for biosensory data acquisition in scope of bees monitoring. We describe the architecture of the system, energy-saving components as well as we discuss the selection of used sensors. The work focuses on energy optimization in a scope of wireless communication. A custom protocol was implemented, which is the basis for presented energy-efficient devices. Data exchange process during...
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Electron Scattering from Methyl Formate (HCOOCH3): A Joint Theoretical and Experimental Study
PublicationElastic low-energy electron collisions with methyl formate have been studied theoretically at the level of various theories. The elastic integral cross section was calculated using Schwinger multichannel and R-matrix methods, in the static-exchange and static-exchange plus polarization levels of approximations for energies up to 15 eV. The absolute total cross section for electron scattering from methyl formate has been measured...
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Theoretical and experimental study on scattering of low-energy electrons by dimethyl and diethyl ethers
PublicationWe report a joint theoretical and experimental investigation on low-energy electron scattering by dimethyl and diethyl ethers. The experimental elastic differential cross sections were measured at impact energies from 1 eV up to 30 eV and scattering angle range of 10◦ to 130◦. Theoretical elastic differential, integral and momentum-transfer cross sections are calculated at impact energies up to 30 eV, employing the Schwinger multichannel...
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Introduction of SAF-T in selected European countries together with applicable national names
Open Research DataAmong the methods used by individual countries in norder to seal the tax collection the introduction of the Standard Audit File for Tax is one of the most important ones.
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Multi-nodal PWR reactor model — Methodology proposition for power distribution coefficients calculation
PublicationIn the paper the multi-nodal Pressurized Water Reactor (PWR) model called Mann’s model is presented. This models is used for modelling purposes of the heat transfer from fuel to coolant in reactor core. The authors expand widely used in literature approach by defining additional coefficients for the heat transfer model. These parameters approximate the power generation distribution in the PWR reactor core according to the to the...
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A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
PublicationThe Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling...
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Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublicationA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
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Assessment of crack resistance of ship steels according to SEP 1390 standard
PublicationThe aim of the study was to evaluate the weldability of E36 nd NVE-36 steels by bending test according to SEP 1390. In the case of the specimen from E36 steel 9 external cracks were found, 5 of which were stopped in the fusion line and 4 in heat affected zone. In the case of the specimen from NVE-36 steel 8 external cracks were found, 4 of which were stopped in the fusion line and 4 in heat affected zone. Results of bending test...
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Power enhancement of the Brayton cycle by steam utilization
PublicationThe paper presents thermodynamic analysis of the gas-steam unit of the 65 MWe combined heat and power station. Numerical analyses of the station was performed for the nominal operation conditions determining the Brayton and combined cycle. Furthermore, steam utilization for the gas turbine propulsion in the Cheng cycle was analysed. In the considered modernization, steam generated in the heat recovery steam generator unit is directed...
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DSC measurments of ammonium vanadate nanocrystals
Open Research DataThe DataSet contains the thermal behavior of the ammonium vanadate nanostructures obtained by the hydrothermal method with different conditions. Differential scanning calorimetry (DSC) measurement was carried out under an argon atmosphere from 40C to 560C (with a heating rate of 10 C/min) using Netzsch STA 449 F1. The results reveal the differences...