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Tytuł:
Low Temperature District Heating — Critical Literature Review
Autorzy:
Dolna, O.
Powiązania:
https://bibliotekanauki.pl/articles/1191845.pdf
Data publikacji:
2018
Wydawca:
Gdańska Szkoła Wyższa
Tematy:
district heating
low temperature district heating
renewables
Opis:
Nowadays, numerous initiatives are being undertaken with the aim to prevent further pollution of air, earth and water. Low temperature district heating (LTDH) offer here an advantage over other heating methods. Implementation of LTDH network into existing buildings have been performed e.g. in Denmark and proved to be feasible without large thermal and in house installation modernisation; however, this must be checked for Polish conditions. The conditions and barriers for such test are discussed here.
Źródło:
Eco-Energetics: technologies, environment, law and economy; 2018, 1; 15--20
2657-5922
2657-7674
Pojawia się w:
Eco-Energetics: technologies, environment, law and economy
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.
Powiązania:
https://bibliotekanauki.pl/articles/2201036.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
Ni-YSZ
cermet
coating
microhardness
heating temperature
heating time
electroless nickel
powłoka
mikrotwardość
temperatura nagrzewania
czas nagrzewania
bezprądowe powlekanie niklem
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.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 113, 1; 5--12
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ zmian temperatury i czasu wygrzewania próbek skał mułowców na rozkład wielkości porów i powierzchnię właściwą BET na podstawie analiz izoterm adsorpcji
Effects of changes in temperature and heating times in the preparation of mudstones rock samples, on pore size distribution and specific surface BET measurements based on adsorption isotherm analysis
Autorzy:
Dudek, Lidia
Powiązania:
https://bibliotekanauki.pl/articles/1834957.pdf
Data publikacji:
2019
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
mułowce
adsorpcja
desorpcja
adsorbent
adsorbat
powierzchnia właściwa
temperatura wygrzewania
mudstones
adsorption
desorption
adsorbate
specific surface area
heating temperature
Opis:
Celem pracy jest przedstawienie efektów wygrzewania próbek skał ilasto-mułowcowych na ich strukturę porową, a konkretnie powierzchnię właściwą BET. Struktura porowa surowych i częściowo wygrzanych próbek była mierzona metodą adsorpcji azotu w niskiej temperaturze, w tym przypadku w temperaturze wrzenia ciekłego azotu. Otrzymane izotermy adsorpcji i desorpcji tych próbek były podobne i można je było zaklasyfikować jako typ II, według klasyfikacji IUPAC (Sing et al., 1985). Badania adsorpcyjne wykonano na próbkach skał ilastomułowcowych z utworów ordowiku i syluru oraz fliszu karpackiego. Selekcję próbek przeprowadzono na podstawie analizy składu mineralogicznego, opierając się na ilościowej analizie rentgenowskiej (tabela 3). Głównym kryterium wyboru była zawartość węglanu wapnia, ze względu na to, iż przyjmuje się, że węglany nie ulegają żadnym przemianom poniżej 550°C. Okazało się jednak, że przemiany następują już w znacznie niższych temperaturach. Dla każdej próbki wykonano co najmniej 30 pomiarów adsorpcyjnych, w sumie wykonując ich około 120 pomiarów. Otrzymano krzywe kumulacyjne oraz funkcje rozkładu objętości porów wyznaczone za pomocą algorytmu BJH (ang. Barrett-Joyner-Halenda) (Barrett et al., 1951), z gałęzi desorpcji przy użyciu równania statystycznej grubości warstwy Halseya i korekcji Faass (Faass, 1981) oraz wartości powierzchni właściwej BET (Brunauer et al., 1938). Analizując otrzymane wyniki można stwierdzić, że wszystkie próbki przed przystąpieniem do badania – w celu minimalizacji błędów pomiarowych związanych z heterogenicznością – należy przesiać przez sito 0,5 mm. Następnie po wygrzaniu i przedmuchaniu próbki w urządzeniu SmartPrep należy zatkać probówkę korkiem w celu eliminacji ponownego zawilgocenia. Konsekwencją wygrzewania próbki już nawet w temperaturze 65°C jest wzrost wartości Ro o 3%, lecz przy wygrzewaniu w 425°C rośnie ona aż o 500%. Po wykonaniu analizy adsorpcji azotem zauważono, że wszystkie próbki, niezależnie od ich współczynnika wzrostu lub spadku powierzchni właściwej BET z temperaturą, wykazują tendencję do lokalnych minimów w zakresie 130–190°C i 360–425°C oraz lokalnych maksimów 65–105°C i 250–320°C, których to wyjaśnienie powinno być przedmiotem osobnej pracy analizującej szczegółowo zjawiska fizycznochemiczne występujące w podobnym trendzie we wszystkich analizowanych próbkach.
The purpose of this work was to show the effects of heating up of mudstones rock samples, on their pore structure and especially on their specific surface BET. Porous structures of both – raw and partly heated samples – were measured using nitrogen adsorption method at low temperature i.e. boiling temperature of liquid nitrogen. Adsorption and desorption isotherms obtained for these samples were similar and they could be classified as type II according to IUPAC classification (Sing et al. 1985). Adsorption testing was conducted on clay-mudstone rock samples from Ordovician, Silurian and Carpathian Flysch layers. Sample selection was based on mineral content analysis outcome from quantitative X-ray analysis. The main selection criteria was calcium carbonate content, due to the fact that theoretically they do not undergo any transformations below 550°C, it turned out, however, that they might occur at much lower temperatures. At least 30 adsorption measurements were taken for each sample, totaling about 120 adsorption measurements. Cumulative curves were obtained together with pore volume distribution functions using BJH (BarrettJoyner-Halenda) (Barrett et al., 1951) algorithm from the desorption branch using Halsey’s statistical layer thickness equation and Faass (Faass, 1981) correction and also specific surface measurements (BET). Analysis of the obtained results allow us to conclude, that all samples should be put through the 0.5 mm sieve before analysis to minimize the error associated with its heterogenity. Later, after the sample has been preheated and Nitrogen vented in SmartPrep apparatus, it has to be cork sealed to eliminate secondary moisture adsorption. The consequence of preheating of a rock sample even at 65°C is the increase in its Vitrinite Reflectance by 3%, but after preheating it at 425°C, VR increases even by 500%. After adsorption analysis it was concluded that all the samples – regardless of whether their BET, change with temperature was positive or negative – showed local minima in 130–190°C and 360–425°C, and local maxima in 65–105°C and 250–320°C which phenomena should be examined in detail in further research, in order to analyse both physical and chemical processes present in similar trend in all analyzed samples.
Źródło:
Nafta-Gaz; 2019, 75, 1; 10-16
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interpolation formulas for coefficients reducing the strength of steel and aluminum alloys in increasing temperatures
Formuły interpolacyjne współczynników redukcyjnych wytrzymałości stali i stopów aluminium w podwyższonej temperaturze
Autorzy:
Gwóźdź, M.
Powiązania:
https://bibliotekanauki.pl/articles/230860.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stal
aluminium
pożar
temperatura nagrzania
wytrzymałość stopu
właściwości mechaniczne
zmniejszenie wytrzymałości
steel
aluminum
fire
heating temperature
alloy strength
mechanical properties
strength reduction
Opis:
Heating of steel or structural aluminum alloys at a speed of 2 to 50 K/min – characterizing the fire conditions - leads to a reduction in mechanical properties of the analyzed alloys. The limit of proportionality fp, real fy and proof f02 yield limit, breaking strength fu and longitudinal limit of elasticity E decrease as the temperature increases. Quantitative evaluation of the thermal conversion in strengths of structural alloys is published in Eurocodes 3 and 9, in the form of dimensionless graphs depicting reduction coefficients and selected (tabulated) discrete values of mechanical properties. The author’s proposal for an analytical formulation of code curves describing thermal reduction of elasticity modulus and strengths of structural alloys recommended for an application in building structures is presented in this paper.
W obliczeniach statycznych konstrukcji metalowych oddziaływania temperatury uwzględnia się w dwóch sytuacjach projektowych. W pierwszej, zwykle trwałej lub przejściowej sytuacji obliczeniowej, temperatura ma charakter oddziaływań technologicznych, które mogą wystąpić zarówno w konstrukcjach stalowych jak i aluminiowych. Druga sytuacja ma charakter wyjątkowy, ponieważ dotyczy temperatury pożarowej, która może wystąpić tylko w budynkach o konstrukcji stalowej (wyroby hutnicze aluminiowe oraz stalowe klasy 4 nie nadają się na konstrukcje budynków zagrożonych potencjalnym pożarem). Przywołany podział oddziaływań temperatury ma dość istotne znaczenie z uwagi na wymaganą dokładność dopasowania formuł analitycznych do wyników empirycznych zestawionych w normach. Nagrzewanie stali lub konstrukcyjnych stopów aluminium z szybkością od 2 do 50 K/min - charakteryzującą warunki technologiczne i pożarowe, prowadzi do redukcji właściwości mechanicznych analizowanych stopów.
Źródło:
Archives of Civil Engineering; 2017, 63, 2; 39-54
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowa metoda interpretacji przestrzeni porowej na podstawie łączenia badań porozymetrii rtęciowej i adsorpcji azotu na przykładzie wybranych łupków menilitowych
Novel method of pore space interpretation based on joint Mercury Intrusion Porosimetry and Nitrogen Adsorption of the selected Menilite Shales
Autorzy:
Dudek, Lidia
Powiązania:
https://bibliotekanauki.pl/articles/1834256.pdf
Data publikacji:
2020
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
łupki menilitowe
adsorpcja
desorpcja
porozymetria rtęciowa
powierzchnia właściwa
temperatura wygrzewania
Menilite Shale
adsorption
desorption
Mercury Injection Capillary Pressure
specific surface area
heating temperature
Opis:
In this paper, a new approach has been shown for the interpretation of the pore space characteristics, consisting in combining pore space volumetric fractional derivatives of mercury intrusion and nitrogen adsorption on the same scale without using any artificial data transformation. This new approach was shown using obtained results of measurements of surface Menilite Shales. It is based on the assumption that for any selected pore diameters, the existing pore space volume is independent of the applied non-wetting liquid agent (mercury, liquid nitrogen, liquid argon etc.). Any recorded differences of these two methods are due to cracking of pore walls under high mercury pressure or their elastic and/or plastic deformations and other interactions between pore building material and the non-wetting liquid used. Significant populations of pores in shales are too small to be measured using only MICP (Mercury Injection Capillary Pressure), which would explain the underestimation of the total porous space. Therefore, for its proper estimation, the complementary method of nitrogen adsorption has been used. The porous structure of Menilite Shale samples preheated at 105°C was measured using the mercury intrusion method MICP at ambient temperature and using nitrogen adsorption at its boiling point temperature of −195.8°C. Volumetric fractional derivatives of pore diameters obtained by these 2 different complementary methods were shown in the form of graphs dV/dD. Based on the porosimetric and helium pycnometric tests both bulk and open porosity was calculated, which allowed to characterise the filtration properties of rock samples. Based on the adsorption testing, the specific surface BET was calculated, as well as the pore size distribution and its total porous volume.
Źródło:
Nafta-Gaz; 2020, 76, 5; 291-298
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superniskotemperaturowa sieć ciepłownicza z indywidualnym źródłem szczytowym w kontekście zaopatrzenia w ciepło budynku wykonanego w technologii tradycyjnej
Ultra-low-temperature district heating with individual peak heat source in context of covering typical detached house heat demand
Autorzy:
Ciapała, B.
Janowski, M.
Jurasz, J.
Powiązania:
https://bibliotekanauki.pl/articles/203625.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
sieć ciepłownicza
ogrzewanie niskotemperaturowe
straty w sieci ciepłowniczej
district heating system
low-temperature heating
district heating heat losses
Opis:
Sieci ciepłownicze są postrzegane jako istotne rozwiązanie mające na celu przeciwdziałanie zmianom klimatu, poprawienie jakości życia oraz przede wszystkim ograniczenie zanieczyszczenia powietrza na skutek tzw. niskiej emisji. W większości zasilane są na podstawie źródeł konwencjonalnych, a ich parametry techniczne zakładają wysoką temperaturę medium. Trendy światowe wskazują na coraz powszechniejszą tendencję projektowania sieci niskotemperaturowych. Rozwiązania te pozwalają na obniżenie strat przesyłowych oraz wykorzystanie powszechnie występujących źródeł o niskiej entalpii. W artykule przedstawiono model matematyczny oraz założenia dotyczące parametrów superniskotemperaturowej sieci ciepłowniczej. Na podstawie godzinowych wartości temperatury dla typowego roku meteorologicznego (warunki polskie) wyznaczono minimalną temperaturę medium sieci ciepłowniczej dla budynku jednorodzinnego o projektowanej stracie ciepła na poziomie 100 W/m2 przy ograniczeniu, że źródło szczytowe zużyje mniej energii niż pompa ciepła o wskaźniku sezonowej efektywności na poziomie 5. W wyniku przeprowadzonych obliczeń wskazano, że najniższa akceptowalna temperatura to 42,5°C i pozwala ona na uzyskanie współczynnika obciążenia na poziomie 60% przy równoczesnym zaspokojeniu 80% zapotrzebowania na ciepło w budynku.
District heating networks are seen as an important solution to combat climate change, improve the quality of life and, above all, reduce air pollution due to so-called low emission. Most of them are powered by conventional sources and their technical parameters assume high medium temperature. However, global trends indicate an increasingly common tendency to design and utilize low-temperature networks. These solutions seem to reduce transmission losses and make it possible to use commonly available low-enthalpy sources. The article presents a mathematical model and assumptions regarding the parameters of a ultra-low-temperature district heating. Based on the hourly temperature values for a typical meteorological year (Polish conditions), the minimum temperature of the heating network medium for a single-family building with designed heat loss of 100 W/m2 was determined with the restriction that the peak source should consume less energy than a heat pump with a seasonal performance factor at level 5. As a result of the carried out calculations, it was indicated that the lowest acceptable temperature is 42.5°C and it allows to obtain a capacity factor of 60% while providing 80% of energy required in the building.
Źródło:
Technika Poszukiwań Geologicznych; 2018, R. 57, nr 2, 2; 79-91
0304-520X
Pojawia się w:
Technika Poszukiwań Geologicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low temperature district heating using waste heat from biogas plant
Autorzy:
Cenian, A.
Noch, T.
Powiązania:
https://bibliotekanauki.pl/articles/1190191.pdf
Data publikacji:
2019
Wydawca:
Gdańska Szkoła Wyższa
Tematy:
low-temperature district-heating network
biogas installation
co-generation
energy efficiency
Opis:
A biogas plant can be a source of waste-heat flows with different thermal parameters. Application of such flows in local, low-temperature district-heating networks is a very attractive option for highly efficient, energetically and economically, co-generation systems applying biogas as the primary energy source.
Źródło:
Eco-Energetics: technologies, environment, law and economy; 2019, 2; 19--28
2657-5922
2657-7674
Pojawia się w:
Eco-Energetics: technologies, environment, law and economy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Waste heat from CHP in biogas plant utilization for local central heating
Autorzy:
Piechowski, L.
Noch, T.
Cenian, A.
Powiązania:
https://bibliotekanauki.pl/articles/1191866.pdf
Data publikacji:
2018
Wydawca:
Gdańska Szkoła Wyższa
Tematy:
biogas
co-generation
heat utilization
heat storage
low temperature district heating
Opis:
The effective utilization of waste heat it is great challenge for highly efficient co-generation based on biogas. The possibility for highly efficient co-generation using biogas is analyzed. The system generating 500 kWe and 700 kWh, where main heat receiver would be village or small city region with central heating system and heat storage system is considered. Both home heating and hot water supply is discussed.
Źródło:
Eco-Energetics: technologies, environment, law and economy; 2018, 1; 89--96
2657-5922
2657-7674
Pojawia się w:
Eco-Energetics: technologies, environment, law and economy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of heating plates temperature on freeze drying energy requirements and quality of dried vegetables
Analiza wplywu temperatury plyt grzejnych liofilizatora na energochlonnosc procesu i cechy jakosciowe suszu z wybranych warzyw
Autorzy:
Krzykowski, A.
Dziki, D.
Polak, R.
Rudy, S.
Powiązania:
https://bibliotekanauki.pl/articles/792446.pdf
Data publikacji:
2012
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
lyophilization
drying
heating plate temperature
freeze dryer
specific drying energy
celery
parsley
carrot
L-ascorbic acid
quality
vegetable
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 2
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental studies of static and dynamic steel arch support load capacity and sliding joint temperature parameters during yielding
Autorzy:
Pytlik, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1853806.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nośność statyczna
wyrobisko
podpora stalowa
yielding steel arch support
support shackle torque
static and dynamic load capacity
support work
arch acceleration in sliding joints
joint sparking and heating temperature during yielding
Opis:
Difficult geological and mining conditions as well as great stresses in the rock mass result in significant deformations of the rocks that surround the workings and also lead to the occurrence of tremors and rock bursts. Yielding steel arch support has been utilised in the face of hard coal extraction under difficult conditions for many years, both in Poland and abroad. A significant improvement in maintaining gallery working stability is achieved by increasing the yielding support load capacity and work through bolting; however, the use of rock bolts is often limited due to factors such as weak roof rock, significant rock mass fracturing, water accumulation, etc. This is why research and design efforts continue in order to increase yielding steel arch support resistance to both static and dynamic loads. Currently, the most commonly employed type of yielding steel arch support is a support system with frames constructed from overlapping steel arches coupled by shackles. The yield of the steel frame is accomplished by means of sliding joints constructed from sections of various profiles (e.g. V, TH or U-type), which slip after the friction force is exceeded; this force is primarily dependent on the type of shackles and the torque of the shackle screw nuts. This article presents the static bench testing results of ŁP10/V36/4/A, ŁP10/V32/4/A and ŁP10/V29/4/A yielding steel arch support systems formed from S480W and S560W steel with increased mechanical properties. The tests were conducted using 2 and 3 shackles in the joint, which made it possible to compare the load capacities, work values and characteristics of various types of support. The following shackle screw torques were used for the tests: Md = 500 Nm – for shackles utilised in the support constructed from V32 and V36 sections. Md = 400 Nm – for shackles utilised in the support constructed from V29 sections. The shackle screw torques used during the tests were greater compared to the currently utilised standard shackle screw torques within the range of Md = 350-450 Nm. Dynamic testing of the sliding joints constructed from V32 section with 2 and 3 shackles was also performed. The SD32/36W shackles utilised during the tests were produced in the reinforced versions and manufactured using S480W steel. Since comparative testing of a rock bolt-reinforced steel arch support system revealed that the bolts would undergo failure at the point of the support yield, a decision was made to investigate the character of the dynamics of this phenomenon. Consequently, this article also presents unique measurement results for top section acceleration values registered in the joints during the conduction of support tests at fullscale.Filming the yield in the joint using high-speed video and thermal cameras made it possible to register the dynamic characteristics of the joint heating process at the arch contact point as well as the mechanical sparks that accompanied it. Considering that these phenomena have thus far been poorly understood, recognising their significance is of great importance from the perspective of occupational safety under the conditions of an explosive atmosphere, especially in the light of the requirements of the new standard EN ISO 80079-36:2016, harmonised with the ATEX directive.
Źródło:
Archives of Mining Sciences; 2020, 65, 3; 469-491
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of high-temperature heating on chemical changes in M7C3 carbides of AISI D2 tool steel
Autorzy:
Nykiel, T.
Hryniewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/411883.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
D2 tool steel
high-temperature heating
Austenitizing
coarse primary M7C3 carbides
chemical composition
Opis:
The paper presents the study results obtained on 16H12MF/NC11LV/D2 tool steel. The main purpose of the study was to establish the chemical composition of the coarse primary M7C3 carbides occurring in that steel after a standard soft annealing. The effect of high-temperature annealing in the air atmosphere was investigated. The study was limited to the decarburized layer, on the distance of about 0.4 mm from the surface, of hardened steel after annealing and austenitizing at 1150 ºC in the air atmosphere for the periods of 30 and 90 minutes. It was found that the coarse primary M7C3 carbides of the annealed D2 tool steel differ significantly as to the contents of Cr, Mo, and V, and in the most degree to the contents of chromium and molybdenum. The average concentration of chromium rises successively with the growth of austenitizing time. On the other hand, the concentrations of molybdenum and vanadium are lower after 30 minutes of austenitizing than their concentrations in the similar carbides of the annealed steel. Prolongation of the austenitizing time up to 90 minutes results in the increase of molybdenum and vanadium contents in the coarse carbides. It was found that austenitizing of AISI D2 tool steel at the temperature of 1150 ºC in the air atmosphere leads to precipitation of the second phase, brighter in the BSE_Z pictures, in relation to the matrix of carbides, with the amount and magnitude being higher with the annealing time.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 17, 3; 258-271
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimisation of the Thermal Process in Ladle Metallurgy in Terms of the Impact on Energy Consumption and the Environmental Burden During Steel Production
Autorzy:
Lampa, Martin
Mokrošová, Lenka
Powiązania:
https://bibliotekanauki.pl/articles/2174906.pdf
Data publikacji:
2022
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
casting ladle
ladle furnace
extra-furnace processing
lining
energy consumption
ecological burden
steel production
continuous casting
high-temperature heating
Opis:
The paper focuses on reducing the energy intensity of ladle metallurgy as part of steel production and the associated reduction of pollutant emissions. It can be achieved by optimising the thermal work of metallurgical aggregates in terms of the impact on energy consumption and the environmental burden of steel production. It is about minimising the heat loss of liquid steel in the casting ladle throughout the entire process, from the melting equipment, through the extra-furnace processing, to the continuous casting of the steel.
Źródło:
Rocznik Ochrona Środowiska; 2022, 24; 246--259
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental testing of the vehicle heating system
Autorzy:
Kucybała, P.
Gawlik, A.
Powiązania:
https://bibliotekanauki.pl/articles/246308.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
heating system
temperature distribution
temperature tests
thermal chamber
Opis:
An important problem in the design of machinery and equipment at the stage of determining their structure is the issue of providing adequate thermal comfort to users while operating in variable climatic and environmental conditions. This issue is of particular importance because all types of machinery and devices are equipped with very expensive and automated control and monitoring system, which should guarantee adequate warming conditions and should work under different climatic conditions. Examples of these tendencies are special solutions for vibroacoustic insulation of the inside of the devices, special air conditioning equipment, special constructions, ergonomic inside solutions. The process of shaping the discussed structural design of vehicles in terms of meeting the relevant technical and operational criteria is currently being increasingly realized through experimental tests of prototypes supported by numerical calculations. The purpose of this paper is to present the methodology of conducting test stand as a stage for the experimental determination and verification of temperature distribution, the location of heating and air conditioning devices in a prototype vehicle in variable climatic conditions (minus 15º C). The research was carried out in a large-scale climate chamber. It covered the process of heating up the passenger area of the bus and the time of temperature stabilization on the inside of the vehicle while operating the heating systems. An additional attempt was made to test the heating system while the vehicle was in motion and to open the vehicle door to simulate the stopping of the vehicle at the bus stop. Another aspect that was analysed was the impact of the installed convector on the vehicle when the liquid heater was off.
Źródło:
Journal of KONES; 2017, 24, 3; 135-141
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature distribution in a brake disc with variable contact pressure
Autorzy:
Topczewska, K.
Powiązania:
https://bibliotekanauki.pl/articles/134744.pdf
Data publikacji:
2016
Wydawca:
ADVSEO
Tematy:
braking
frictional heating
temperature
brake disc
Opis:
The aim of this study was to investigate the influence of the time of pressure increase during single braking on the temperature in a brake disc. The case of linear pressure increase from zero to nominal value in the initial stage of braking and maintaining this value to standstill was considered. The time distribution of the sliding velocity of frictional elements was determined from the differential equation of motion with the initial condition. Based on the time distributions of pressure and sliding velocity, the intensity of the frictional heat flux, which affects on the disc surface, was determined. Spatio-temporal distribution of the temperature in a brake disc was found from analytical solution of the heat conduction boundary–value problem for semi–space heated on the outer surface heat flux with known a priori intensity. The numerical analysis conducted allowed to determine engineering equation, which describes relation between maximum temperature and the time of pressure increase.
Źródło:
Technical Issues; 2016, 1; 90-95
2392-3954
Pojawia się w:
Technical Issues
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The calculations of the efficency of the lightweight floor heating according to nordtest method NT VVS 127
Autorzy:
Werner-Juszczuk, Anna Justyna
Powiązania:
https://bibliotekanauki.pl/chapters/31233737.pdf
Data publikacji:
2021
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
lightweight floor heating
standard
dry floor heating
heat flux density
surface temperature
Opis:
The suitability of Nordest Method NT VVS 127 for determining the operational parameters of the lightweight floor heating with a dry screed was tested. The methodology of surface temperature and heat flux density determination according to Nordest Method NT VVS 127 was presented. The calculations were made for lightweight floor heating with a dry screed of various thickness and variable water temperature. The results were compared with the numerical calculations made with ANSYS Steady-State Thermal Solver. The operational parameters of the floor heating were also determined using the method presented in PN-EN 1264 standard. The difference between the surface temperature determined according to Nordest Method NT VVS 127 and the numerical values does not exceed 5,68 K, for the heat flux density the error is up to 55,5%. The difference between the surface temperature determined according to PN-EN 1264 and the numerical value does not exceed 0,2 K, for the heat flux density the error is up to 8,5%. It was found, that the PN-EN 1264 standard is more applicable to determining the operational parameters of lightweight floor heating with a dry screed than Nordest Method NT VVS 127.
Źródło:
Innovations – Sustainability – Modernity – Openness. Modernity in engineering; 159-172
9788366391901
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 87

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