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Wyszukujesz frazę "heating time" wg kryterium: Temat


Tytuł:
Numerical investigation of biomass fast pyrolysis in a free fall reactor
Autorzy:
Bieniek, Artur
Jerzak, Wojciech
Magdziarz, Aneta
Tematy:
fast pyrolysis
biomass
Euler–Lagrange
drop tube reactor
heating time
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/1955021.pdf  Link otwiera się w nowym oknie
Opis:
This work presents two-dimensional numerical investigations of fast pyrolysis of red oak in a free fall reactor. The Euler–Lagrange approach of multiphase flow theory was proposed in order to describe the behaviour of solid particles in the gaseous domain. The main goal of this study was to examine the impact of the flow rate of inert gas on the pyrolysis process. Calculation domain of the reactor was made according to data found in the literature review. Volume flow rates were 3, 9, 18, and 25 l/min, respectively. Nitrogen was selected as an inert gas. Biomass pyrolysis was conducted at 550◦C with a constant mass flow rate of biomass particles equal to 1 kg/h. A parallel multistage reaction mechanism was applied for the thermal conversion of red oak particles. The composition of biomass was represented by three main pseudo-components: cellulose, hemicellulose and lignin. The received products of pyrolysis were designated into three groups: solid residue (char and unreacted particles), primary tars and noncondensable gases. In this work the impact of the volume flow rate on the heating time of solid particle, temperature distribution, yields and char mass fraction has been analysed. The numerical solutions were verified according to the literature results when the flow of nitrogen was set at 18 l/min. The calculated results showed that biomass particles could be heated for longer when the flow rate of nitrogen was reduced, allowing for a greater concentration of volatile matter.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heat treatment on microhardness of electroless Ni-YSZ cermet coating
Autorzy:
Bahiyah Baba, N.
Ghazali, A. S.
Abdul Rahman, A. H.
Sharif, S.
Tematy:
Ni-YSZ
cermet
coating
microhardness
heating temperature
heating time
electroless nickel
powłoka
mikrotwardość
temperatura nagrzewania
czas nagrzewania
bezprądowe powlekanie niklem
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Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:
https://bibliotekanauki.pl/articles/2201036.pdf  Link otwiera się w nowym oknie
Opis:
Purpose: The paper discussed the effect of heat treatment on electroless nickel-yttria-stabilised zirconia (Ni-YSZ) cermet coating. Ni-YSZ cermet coating has potential applications such as cutting tools, thermal barriers, solid oxide fuel anode, and various others. The compatibility of ceramic YSZ and metallic nickel in terms of the mechanical properties such as hardness by varying the heating temperature, time and ceramic particle size is highlighted. Design/methodology/approach: Ni-YSZ cermet coating was deposited onto a highspeed steel substrate using the electroless nickel co-deposition method. The temperature and time were varied in a range of 300-400°C and 1-2 hours, respectively. The microhardness measurements were carried out using a Vickers microhardness tester (Shimadzu) according to ISO 6507-4. The surface characterisation of the cermet coating was carried out using JOEL Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray (EDX) JSM 7800F. The crystallographic structure of materials was analysed by X-ray diffraction (XRD) Bruker D8 Advance instrument. Findings: It was found that the microhardness of Ni-YSZ cermet coating with the ratio of 70:30, respectively, is directly proportional to the heating temperature and time. Heating the Ni-YSZ cermet coating at 300°C from room temperature (rtp) to 1 hour shows a 12% microhardness increment, while from 1 to 2 hours gives a 19% increment. Compared to heating at 350°C and 400°C, the increment is more significant at 33% and 49% for rtp to 1 hour and 8% and 16% for 1 to 2 hours, respectively. In addition, the effect of varying YSZ particle size in the Ni-YSZ cermet gave response differently for heating temperature and heating time. Research limitations/implications: The paper is only limited to the discussion of the heat treatment effect on Ni-YSZ cermet coating hardness property. The tribological effect will be in future work. Practical implications: The microhardness data may vary due to the Vickers microhardness force applied and the amount of ceramic particle incorporation and phosphorus content in the nickel matrix. Originality/value: The value of this work is the compatibility of the ceramic YSZ and metallic nickel matrix in terms of mechanical properties, such as hardness, upon heat treatment.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of heating time of a bundle of steel bars
Badanie czasu nagrzewania wiązki prętów stalowych
Autorzy:
Aghbalyan, S.
Bagdasaryan, V.
Wyczółkowski, R.
Tematy:
steel bar
heating time
thermal conductivity
effective thermal conductivity
energy balance
heat treatment
process optimization
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Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Powiązania:
https://bibliotekanauki.pl/articles/28766072.pdf  Link otwiera się w nowym oknie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heating-times of tungsten filament incandescent lamps
Autorzy:
Dulli, Chandra Agrawal
Tematy:
10-1000 W
Tungsten filament lamps
and heating-time
linear and coiled configurations
lumen output
steady-state operation
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Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:
https://bibliotekanauki.pl/articles/1113541.pdf  Link otwiera się w nowym oknie
Opis:
Electricity provides power to incandescent lamps to heat the filament hot enough so that it provides light for illumination. The time taken to achieve a state of full brilliance after being turned on is so fast that it may be presumed to be adiabatic, hence it is deemed adiabatic heating time. In view of the fact that in actual practice simultaneously black-body radiation cools the filament, the General Electric in its bulletin provides a better time scale describing heating and cooling of filament. These are average times required for the filament to warm up to 90 per cent light output after the circuit is closed, or to cool down to 10 per cent after the circuit is opened, respectively. The exercise of estimating luminous flux and heating-times for typical 10, 100, 500 and 1000 W lamps have been undertaken for the first time for the benefit of students. This problem involves three disciplines electricity, optics and heat. The first describes the power needed to heat the filament quickly, optics then helps us in determining the light output and discipline of heat provides methods for solving the heat equation in order to estimate time to light or time to darkness. The study reveals that the supposition of linear configurations for the filaments neither matches luminous flux nor the heating-times. HS Leff’s suggestion of introducing a shadow factor which reduces the exposed surface area, as it so happens in the coiled filaments, successfully explains the measured observations.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ warunków ogrzewania nasion rzepaku i gorczycy białej na cechy olejów do produkcji biodiesla
Impact of heating conditions of rapeseed and mustard seeds on the characteristics of oils for the biodiesel production
Autorzy:
Tanska, M.
Rotkiewicz, D.
Ambrosewicz-Walacik, M.
Tematy:
rzepak
gorczyca biala
nasiona
ogrzewanie
temperatura
czas ogrzewania
tloczenie
wydajnosc tloczenia
oleje roslinne
biodiesel
jakosc oleju
rape
white mustard
seed
heating
temperature
heating time
oil pressing
efficiency
plant oil
biodiesel fuel
oil quality
Pokaż więcej
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Powiązania:
https://bibliotekanauki.pl/articles/833921.pdf  Link otwiera się w nowym oknie
Opis:
Celem badań było określenie wpływu zróżnicowanych warunków ogrzewania nasion rzepaku i gorczycy białej na wydajność tłoczenia oraz cechy olejów, jako potencjalnych surowców do produkcji biodiesla. Nasiona rzepaku i gorczycy poddano ogrzewaniu w trzech temperaturach (60, 80 i 100°C) przez okres 30, 60 i 90 min, a następnie wytłoczono oleje na laboratoryjnej prasie ślimakowej. Jakość olejów określono poprzez oznaczenie zawartości wody i związków lotnych, stopnia hydrolizy i utlenienia, zawartości chlorofilu i fosforu, barwy oraz składu kwasów tłuszczowych. Stwierdzono, że wraz ze wzrostem temperatury i czasu ogrzewania nasion następowało stopniowe zwiększanie wydajności tłoczenia, przy równocześnie istotnym pogarszaniu cech olejów. Oleje wydobyte z nasion ogrzewanych w najbardziej drastycznych warunkach, tj. 100°C/90 min, cechowały się wprawdzie najniższą zawartością wody i związków lotnych, ale najwyższą zawartością wolnych kwasów tłuszczowych, nadtlenków, barwników chlorofilowych i związków fosforu. Wykazano także, że ogrzewanie nasion rzepaku nie spowodowało zmian w składzie kwasów tłuszczowych. Biorąc pod uwagę zarówno wydajność tłoczenia, jak i jakość olejów w kontekście przydatności do produkcji biodiesla, za najbardziej optymalne warunki uznano ogrzewanie nasion w temperaturze 80°C w czasie 60 min.
The aim of the study was to determine the effect of heating conditions of rapeseed and mustard seeds on the pressing yield and characteristics of oils as potential materials for the biodiesel productions. Oils have been pressed from seeds heated at temperatures of 60, 80 and 100°C for 30, 60 and 90 minutes. Pressing was carried out in a laboratory expeller. Quality of oils was defined by determining water and volatile compound contents, the degree of hydrolysis and oxidation, content of chlorophyll and phosphorus, color and the fatty acids composition. It was found that with the increasing temperature and time of heating condition the yield of pressing increased while the quality of oils deteriorated. Oils extracted from seeds heated in the most drastic conditions, 100°C/90 min, were characterized by the lowest water and volatile compounds content and the highest amount of free fatty acids, peroxides, chlorophyll pigments and phosphorus compounds. It was also shown that heating of rape seeds has not changed the fatty acids composition. Taking into consideration the yield of pressing and the quality of oils in terms of suitability for the biodiesel production, the most optimum heating condition of seeds was at 80°C for 60 min.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frictional heating with time-dependent specific power of friction
Autorzy:
Topczewska, K.
Tematy:
brake disc
frictional heating
temperature
time-dependent power of friction
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Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/articles/386356.pdf  Link otwiera się w nowym oknie
Opis:
In this paper analytical solutions of the thermal problems of friction were received. The appropriate boundary-value problems of heat conduction were formulated and solved for a homogeneous semi–space (a brake disc) heated on its free surface by frictional heat fluxes with different and time-dependent intensities. Solutions were obtained in dimensionless form using Duhamel's theorem. Based on received solutions, evolution and spatial distribution of the dimensionless temperature were analyzed using numerical methods. The numerical results allowed to determine influence of the time distribution of friction power on the spatio-temporal temperature distribution in brake disc.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal stresses due to frictional heating with time-dependent specific power of friction
Autorzy:
Topczewska, K.
Tematy:
frictional heating
temperature
thermal stresses
time-dependent power of friction
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Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/articles/386412.pdf  Link otwiera się w nowym oknie
Opis:
In this paper influence of temporal profile of the specific friction power (i.e. the product of the coefficient of friction, sliding velocity and contact pressure) on thermal stresses in a friction element during braking was investigated. Spatio-temporal distributions of thermal stresses were analytically determined for a subsurface layer of the friction element, based on the model of thermal bending of a thick plate with unfixed edges (Timoshenko and Goodier, 1970). To conduct calculations, the fields of dimensionless temperature were used. These fields were received in the article (Topczewska, 2017) as solutions to a one-dimensional boundary-value problem of heat conduction for a semi-space heated on its outer surface by fictional heat flux with three, different time profiles of the friction power.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The problem of control of rod heating process with nonseparated conditions at intermediate moments of time
Autorzy:
Barseghyan, Vanya R.
Tematy:
heating control
temperature
intermediate moments of time
nonseparated multipoint conditions
complete controllability
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/1845513.pdf  Link otwiera się w nowym oknie
Opis:
The problem of control of rod heating process by changing the temperature along the rod whose ends are thermally insulated is considered. It is assumed that, along with the classical boundary conditions, nonseparated multipoint intermediate conditions are also given. Using the method of separation of variables and methods of the theory of control of finite-dimensional systems with multipoint intermediate conditions, a constructive approach is proposed to build the sought function of temperature control action. A necessary and sufficient condition is obtained, which the function of the distribution of the rod temperature must satisfy, so that under any feasible initial, nonseparated intermediate, and final conditions, the problem is completely controllable. As an application of the proposed approach, control action with given nonseparated conditions on the values of the rod temperature distribution function at the two intermediate moments of time is constructed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The problem of control of rod heating process with nonseparated conditions at intermediate moments of time
Autorzy:
Barseghyan, Vanya R.
Tematy:
heating control
temperature
intermediate moments of time
nonseparated multipoint conditions
complete controllability
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/1845524.pdf  Link otwiera się w nowym oknie
Opis:
The problem of control of rod heating process by changing the temperature along the rod whose ends are thermally insulated is considered. It is assumed that, along with the classical boundary conditions, nonseparated multipoint intermediate conditions are also given. Using the method of separation of variables and methods of the theory of control of finite-dimensional systems with multipoint intermediate conditions, a constructive approach is proposed to build the sought function of temperature control action. A necessary and sufficient condition is obtained, which the function of the distribution of the rod temperature must satisfy, so that under any feasible initial, nonseparated intermediate, and final conditions, the problem is completely controllable. As an application of the proposed approach, control action with given nonseparated conditions on the values of the rod temperature distribution function at the two intermediate moments of time is constructed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermophysical and chemical properties of perennial energy crops depending on harvest period
Autorzy:
Stolarski, M.J.
Krzyzaniak, M.
Snieg, M.
Slominska, E.
Piorkowski, M.
Filipkowski, R.
Tematy:
thermophysical property
chemical property
perennial crop
harvest time
biomass
heating value
ash content
chemical composition
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/26318.pdf  Link otwiera się w nowym oknie
Opis:
This paper presents analyses of the thermophysical and chemical properties of eleven perennial crop species harvested in one-year rotation cycles. The crops included four species grown for biomass in the form of straw, five species producing semi-wood biomass, and two species yielding wood biomass. The research comprised three consecutive crop harvests. In each harvesting season, biomass samples for analyses were taken on six dates at one-month intervals. Thermophysical and chemical properties of the biomass were significantly differentiated within the main experimental factors and their interactions. The biomass produced by Virginia mallow had the best quality parameters as solid fuel. In fact, it achieved the lowest water content and the highest lower heating value during all of the analyzed seasons and harvest dates. The biomass of the species yielding straw or semi-wood products attained better quality as solid fuel on later harvest dates. In turn, the quality of willow biomass remained practically unchanged between the harvest dates.
Dostawca treści:
Biblioteka Nauki
Artykuł

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