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Search results for: HEAT TREATMENT
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HEAT TREATMENT OF METALS
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The effect of heat treatment of hardwood on the specific cutting resistance
PublicationW pracy przedstawiono wyniki badań mocy skrawania podczas przecierania modyfikowanego i niemodyfikowanego termicznie drewna dębowego i jesionowego na pilarce ramowej PRW15M. W pierwszym etapie badań, graniakowe próbki drewna dębowego i jesionowego były modyfikowane termicznie za pomocą przegrzanej pary (temperatura 197C, czas 4 h) w parzelni wysokotemperaturowej, w warunkach przemysłowych. Następnie, wyznaczono właściwe powierzchniowe...
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Influence of the heat treatment on corrosion characteristics of the Superston alloy
PublicationW artykule przedstawiono wpływ hartowania i odpuszczania na twardość i właściwości korozyjne stopu Superston, stosowanego na śruby okrętowe. Stwierdzono, iż hartowanie z temperatury 900 st.C i odpuszczanie w temperaturze 550 st.C znacząco podwyższa odporność na korozję stopu Superston w 3% roztworze NaCl w porownaniu ze stanem odlanym.
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Microwave heat treatment application to pasteurization of human milk
PublicationA prototype of microwave pasteurizer has been proposed as an alternative for holder pasteurization (HP) routinely used in Human Milk Bank (HMB), ensuring microbiological safety of human milk (HM). It was shown that the time of heat generation was about 15–16 min shorter by applying the microwave than in HP. Total inactivation of heat-sensitive bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus...
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HTM-Journal of Heat Treatment and Materials
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Underwater in situ local heat treatment by additional stitches for improving the weldability of steel
PublicationIn this paper the influence of in situ local heat treatment performed by additional stitches on the weldability of high-strength low-alloy (HSLA) S355J2C+N steel was tested. The investigated steel is characterized by high susceptibility to cold cracking. It is necessary to find a method to improve the quality of welded joints. The local heat treatment was applied as an eect of bead-on plate welding made on the face of a Tekken...
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Enhanced Electrochemical Performance of MnCo1.5Fe0.5O4Spinel for Oxygen Evolution Reaction through Heat Treatment
PublicationMnCo1.5Fe0.5O4 spinel oxide was synthesized using the sol−gel technique, followed by heat treatment at various temperatures (400, 600, 800, and 1000 °C). The prepared materials were examined as anode electrocatalysts for watersplitting systems in alkaline environments. Solid-state characterization methods, such as powder X-ray diffraction and X-ray absorption spectroscopy (XAS), were used to analyze the materials’ crystallographic...
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Application of mechanical Barkhausen noise in assessment of X20 steel properties after heat treatment
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Stress corrosion cracking of the 26H2MF and 34HNM constructional allaysteels of different heat treatment in hydrocarbons
PublicationBadane są dwie stale stopowe 26HZMF i 34HNM o różnych właściwościach mechanicznych w różnych środowiskach.
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Influence of Heat Treatment Temperature on Fatigue Toughness in Medium-Carbon High-Strength Steels
PublicationCurrent research has demonstrated that the tempering temperature affects the martensitic transformation of medium-carbon high-strength steels. This temperature plays an important role in the final microstructure, percentage ratios of martensite to ferrite phases and, consequently, in the mechanical properties and the fatigue response. So far, the relationship between the martensitic tempering temperature and the cyclic deformation...
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Heat treatment effect on Eu3+ doped TeO2-BaO-Bi2O3 glass systems with Ag nanoparticles.
PublicationGlass systems of 73TeO2-4BaO-3Bi2O3-2Eu2O3-xAg ( in molar ratio where x= 0, 1, 2, 3) compositions have been successfully synthesized. Silver nanoparticles were obtained with the employment of heat treatment (HT) procedure executed at 350 °C. Glass transition temperatures of different compositions have been determined through DSC measurements. XRD measurement results presented characteristic amorphous halo indicating lack of long...
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Wpływ obróbki cieplnej na strukturę stali krzemowej. The heat treatment influence on the silicon steel morphology
PublicationStal sprężynową 55S2 poddano obróbce cieplnej przy poprawnych i zawyżonych paramatrach temperaturowo-czasowych. Dla materiału o wadliwej strukturze wyjściowej, dobór wyższych temperatur i czasów obróbki pozwolił na otrzymanie bardziej poprawnych struktur i własności materiału.
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Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment
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On the Application of Magnetoacoustic Emission for a Nondestructive Assessment of the Post Welding Heat Treatment of High Chromium Steel Weld Seams
PublicationThe paper analyses the possibility of post weld heat treatment (PWHT) quality assessment with the help of magnetoacoustic emission (MAE) signal measurements. Two welded superheater tubes, made of high chromium VM12 steel, were analysed—as welded and heat treated one. The analysed sample in the as welded state exhibited significantly higher hardness, accompanied by a big difference in the MAE signal intensity (of order of about...
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Trace analyses of gaseous products formed during heat treatment of high stage H2SO4-GICs and expanded graphite
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Influence of retrogression and reaging (RRA) heat treatment on microstructure, mechanical and chemical behaviour of an Al-Zn-Mg alloy
PublicationBadano metodą stałego wolnego rozciągania w wodzie morskiej wpływ czasu i temperatury nawrotu oraz powtórnego starzenia na czas do zniszczenia, energię zniszczenia, przewężenie i odkształcenie. Stwierdzono ogólnie niewielki wpływ, przy czym wzrostowi odporności na korozję naprężeniową towarzyszył spadek właściwości mechanicznych. Obserwowane zmiany właściwości przypisano zmianom struktury dyslokacyjnej i mikrostruktury.
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Effect of heat treatment on the diffusion intermixing and structure of the Cu thin film on Si (111) substrate: a molecular dynamics simulation study
PublicationThis work is devoted to the study of the diffusion process at the interface between copper films with a thickness of 2, 3, 4, 7 and 10 atomic monolayers and silicon substrate by molecular dynamics simulation method. For this purpose, the variation of the concentration of copper and silicon along the perpendicular direction to the interface was investigated. An analysis of the density profile along this direction made it possible...
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The Influence of Long-Term Heat Treatment on Microstructure of Zr-Modified Aluminide Coating Deposited by CVD Method on MAR M200+Hf Nickel Superalloy
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METAL SCIENCE AND HEAT TREATMENT
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Nonlinear impedance of Bi2VO5.5 ceramic of thickness 2.52 mm (after second heat-treatment at 913 K) was measured at high temperature range with impedance spectroscopy method
Open Research DataThe nonlinear electrical properties of Bi2VO5.5 ceramic of thickness 2.52 mm (after second heat-treatment at 913 K) was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage and temperature for Bi2VO5.5 ceramic of thickness 2.52 mm (after first heat-treatment at 913 K) was measured at different frequencies with impedance spectroscopy method
Open Research DataThe nonlinear electrical properties of Bi2VO5.5 ceramic of thickness 2.52 mm was measured by impedance spectroscopy method.
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Effect of Different Vacuum Heat Treatments on the Microstructure of a Low Alloyed Sintered Steel
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Effect of Electron Beam Power Density on the Structure of Titanium Under Non-Vacuum Electron-Beam Treatment
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Influence of Cement Replacement with Sewage Sludge Ash (SSA) on the Heat of Hydration of Cement Mortar
PublicationThe amount of fly ash from the incineration of sewage sludge is increasing all over the world, and its utilization is becoming a serious environmental problem. In the study, a type of sewage sludge ash (SSA) collected directly from the municipal sewage treatment plant was used. Five levels of cement replacement (2.5%, 5%, 7.5%, 10% and 20%) and unchanged water-to-binder (w/b) ratio (0.55) were used. The purpose of the study was...
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Theoretical analysis of heat transfer between a liquid layer formed by an impinginf gas liquid jet AND a solid surface
PublicationHeat transfer phenomenon between a horizontal solid surface and a liquid layer created on a surface by an axisymmetrical liquid gas impinging jet has been analysed. The analytical treatment of the phenomenon is devoted to the area whose diameter is lower than the diameter of the hydraulic jump. W pracy przedstawiono teoretyczną analizę wymiany ciepła pomiędzy warstwą cieczy a stałą powierzchnią po której przepływa.
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Proposal of a mobile medical waste incinerator with automatic waste feeder and heat recovery system
PublicationThe paper presents and discusses the issue of medical waste (including hazardous ones) and their proper management. Inappropriate handling of infectious medical waste directly endangers the human being health and the environment. Infectious waste must therefore be properly disposed of – one of the most commonly used methods is the thermal treatment in the incinerators tailored for this purpose. During designing an incinerator unit,...
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Bartosz Dawidowicz dr inż.
PeopleHe graduated from the Faculty of Mechanical Engineering at Gdańsk University of Technology MSc Eng. - Faculty of Mechanical Engineering, Gdansk University of Technology: specialization: Machines and Equipment of Food Industry (2000)PhD - Faculty of Mechanical Engineering, Gdansk University of Technology, discipline: construction and operation of machines, specialization: heat transfer (2008) Main areas of scientific activity related...
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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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Distribution of heat generated by a local heat source
PublicationW pracy przedstawiono analizę rozpływu ciepła wygenerowanego przez lokalne źródło umieszczone w płycie, po której przepływa warstwa wody.
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High-temperature heat pumps – potential technology for heat recovery and production of process heat
PublicationIn the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively....
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Elementary analysis and energetic potential of the sludge from the Gdynia Dębogórze and Lębork wastewater treatment plants
PublicationThe paper aims to show the results of the elementary analysis of the sewage sludges from wastewater treatment plants in Gdynia Dębogórze and Lębork as well as measurements of the heat of combustion and the calculated calorific values according to regulation PN-93/Z-15008, taking into account water content and the composition of sewage sludge at different utilisation stages. The results presented in this paper are based on the analysis...
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Proposal of a Mobile Medical Waste Incinerator with Application of Automatic Waste Feeder and Heat Recovery System as a Novelty in Poland
PublicationThe paper presents and discusses the issues of medical waste (including hazardous ones) and the problems regarding their proper management in Poland. Inappropriate handling of infectious medical waste directly endangers human health and the environment. Infectious waste must be properly disposed of—in practice, the only method of their disposal available in Poland is a thermal treatment in the incinerators tailored for this purpose....
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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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SEM of TiO2 heated at 400-600oC in Ar or H2
Open Research DataData contain some SEM images of TiO2 taken after its heat treatment in Ar or H2 at 400-600oC. Treated TiO2 was crystalline anatase phase with 3-4 % of rutile nclei.
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Two-phase thermosiphon heat exchanger for heat recovery
PublicationW pracy przedstawiono wyniki badań eksperymentalnych dotyczących wpływu geometrii pęku rur, rodzaju powierzni przejmowania ciepła parownika oraz płynu pośredniego na całkowitą wydajność dwufazowego termosyfonowego wymiennika ciepła (DTWC). Badaniu poddano sześć prototypowych DTWC z dwiema podziałkami rur w parowniku, dla trzech rodzajów powierzchni rur parownika oraz z zastosowaniem trzech rodzajów płynów pośrednich. Lepszą wydajność...
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Boiling heat transfer performance of the thermosiphon heat exchanger
PublicationPrzedstawiono wyniki badań eksperymentalnych prototypowego, termosyfonowgo wymiennika ciepła. W szczególności określono wpływ geometrii pęku rur, stanu powierzchni rurek oraz poziomu cieczy w parowniku na wydajność cieplną wymiennika.
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Heat transfer characteristics of a two-phase thermosyphon heat exchanger
PublicationPrzedstawiono wyniki badań wpływu geometrii parownika, rodzaju rur użytych do budowy parownika, rodzaju cieczy pośredniej oraz poziomu cieczy nad najwyższym rzędem rur na działanie dwufazowego, termosyfonowego wymiennika ciepła. Zaprezentowano algorytm obliczeń przedstawionego wymiennika.
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HEAT TRANSFER CHARACTERISTICS OF ENHANCED SHELL AND COIL HEAT EXCHANGER
PublicationIn the paper authors presented their own constructions of shell and tube heat exchangers with intensified heat transfer. The shell and coils heat exchangers are in common use in heat ventilations and air conditioning systems. Those types of recuperators are quite simple constructions, the low value of pressure drops and good conditions of heat transfer. The present study shows an experimental investigation of the heat transfer...
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Heat transfer intensification by enlarged surface roughness in the plate heat exchanger
PublicationIn the paper an experimental analysis of passive heat transfer intensification technique employed in the case of the plate heat exchanger is presented. The passive intensification was obtained by a modification of the heat transfer surface. The roughness of surface was increased by a use of glass micro-beads. Single-phase convective heat transfer in the water-water system was studied. The experiment was accomplished in two stages....
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Possibilities of heat transfer augmentation in heat exchangers with minichannels for marine applications
PublicationIn the paper, new trends in development of microchannel heat exchangers are presented. The exchangers developed in this way can be applied in marine applications. Main attention was focused on heat exchangers design with reduced size of passages namely based on microchannels. In our opinion future development of high power heat exchangers will be based on networks micro heat exchangers.
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublicationIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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High Performance Tubular Heat Exchanger with Minijet Heat Transfer Enhancement
PublicationIn the paper, the original cylindrical heat exchanger with minijets (MJHE) was introduced. The systematic experimental analysis of the prototype heat exchanger was described with special attention paid to such parameters as the heat transfer effectiveness, heat transfer rates, overall heat transfer coefficients, and pressure drop. The heat transfer coefficients were determined based on Wilson plot method, the most suitable approach...
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Applicability of arrays of microjets heat transfer correlations to design compact heat exchangers
PublicationThe article presents experimental studies on a compact heat exchanger with heat transfer intensification by means of impinging microjets. The pursuit to provide high performance of heat exchangers is a response to the demand both in economics and in the universal tendency to miniaturization of industrial equipment. This paper presents the design and tests of a prototype, microjet heat exchanger. The modular design of the heat exchanger...
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Management of low-temperature heat source by ORC aided by additional heat source
PublicationIn the paper presented is a concept to utilize waste heat from the power plant with the aid of the low-temperature ORC cycle. The ORC system is heated from two heat sources, the first one being the flow rate of waste heat obtained from the exhaust gases. Subsequently, the working fluid in the cycle is additionally heated by the condensing steam from the low pressure turbine extraction points increasing in such way the level of...
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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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Turbulent heat transfer in thin liquid films at low and high heat fluxes
PublicationW pracy przedstawiono rozważania turbulentnej wymiany ciepła w cienkich filmach cieczowych powstałych w wyniku uderzenia strugi przy małych i dużych strumieniach ciepła. W ostatnim przypadku może dojść do wrzenia filmu cieczowego. Oba zjawiska zamodelowano i uzyskano odpowiednie rozkłady temperatury i pedkosci.
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The influence of microjet array area ratio on heat transfer in the compact heat exchanger
PublicationThe paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger....
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Heat transfer and pressure drop characteristics of the silicone-based plate heat exchanger
PublicationThe paper presents an experimental investigation of a silicone based heat exchanger, with passive heat transfer intensification by means of surface enhancement. The main objective of this paper was to experimentally investigate the performance of a heat exchanger module with the enhanced surface. Heat transfer in the test section has been examined and described with precise measurements of thermal and flow conditions. Reported...
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Heat transfer in plate heat exchanger channels: experimental validation of selected correlation equations
PublicationThis study is focused on experimental investigation of selected type of brazed plate heat exchanger. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. The main aim of the paper was to experimentally check ability of several correlations published in the literature to predict heat transfer coefficients by comparison experimentally obtained data with appropriate predictions. The...
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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...