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Tytuł:
Application of Nanoparticles in the Process of Phase Change Paraffin in a Chamber
Autorzy:
Alizadeh, As’ad
Powiązania:
https://bibliotekanauki.pl/articles/102698.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
aluminum oxide
phase change material
nusselt number
nanoparticles
tlenek glinu
materiał o przemianie fazowej
liczba Nusselta
nanocząstki
Opis:
In this study, melting of a phase changing material enriched with nanoparticles in a circular ring-rectangular enclosure was investigated and the results were analyzed. At the beginning of the melting process in the absence of a natural displacement, the mechanism of conduction heat transfer around the hot cylinder is the dominant mechanism. Over time, natural displacement gradually appears and deforms the melting boundary above the cylinder. Over time, when the thickness of the liquid phase grows, the thermal resistance increases, this can be verified by reviewing the Nusselt chart. So this phenomenon reduces the rate of melting and temperature changes. The results show that increasing the nanoparticle volume fraction due to increased conductivity and decreasing latent heat causes an increase in the melting rate and the amount of energy absorbed. From the study of various volume fractions, it can be concluded that the use of a higher volume fraction of 3% is more appropriate both in terms of energy and in terms of the melting rate. However, it should be taken into account that if the melting rate exceeds this value, it may cause agglomeration and deposition of nanoparticles and reducing system efficiency.
Źródło:
Advances in Science and Technology. Research Journal; 2019, 13, 3; 113-119
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reducing Melt Surface Turbulence by Employing Surge and Filter in a Conventional Non-Pressurizing Gating System: Simulation and Experiment
Autorzy:
Baghani, Amir
Kheirabi, Ali
Bahmani, Ahmad
Khalilpour, Hamid
Powiązania:
https://bibliotekanauki.pl/articles/2049678.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum casting
filter
surge
oxide bifilms
failure analysis
Weibull module
mold filling simulation
Opis:
Tensile strength of aluminum castings has been improved by employing surge and filter in a conventional non-pressurizing gating system. For this purpose, three non-pressurizing bottom-gating systems were designed where the first design was a simple design with no filter and no surge, in the second design filter and in the third one surge was added to the end of runner. Tensile strength, Weibull module, scanning electron microscopy, chemical analysis, and melt pattern during the mold filling were thoroughly analyzed to compare these three designs. it was observed that employing filter and surge in the gating system reduces flow kinetic energy and consequently avoid surface turbulence and air entrainment, which leads to castings with fewer defects and higher reliabilities. Finally, it found that appropriate use of surge in the running system can be as effective as employing a filter in reducing melt front velocity.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 397-405
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena wpływu przygotowania podłoża na właściwości tribologiczne nanoceramicznych warstw tlenkowych
An estimation of the influence of the substrate preparation on tribological properties of nanoceramic oxide layers
Autorzy:
Bara, M.
Powiązania:
https://bibliotekanauki.pl/articles/188427.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
warstwa tlenkowa
właściwości tribologiczne
trawienie aluminium
tribological properties
oxide layers
aluminum etching
Opis:
W artykule zostały przedstawione rezultaty badań tribologicznych warstw tlenkowych wytwarzanych na podłożu stopu aluminium o różnym stopniu przygotowania powierzchni we współpracy ślizgowej z tworzywem sztucznym. Utylitarnym celem badań było ograniczenie niekorzystnego wpływu nierówności powierzchni warstwy tlenkowej w procesie zużywania ściernego tworzywa w skojarzeniu ślizgowym z warstwą. Cel ten osiągnięto poprzez określenie wpływu przygotowania podłoża na kształtowanie topografii powierzchni oraz właściwości tribologiczne nanoceramicznych warstw tlenkowych. Badania tribologiczne przeprowadzono na stanowisku tarciowo-zużyciowym typu trzpień–płaszczyzna. Analiza wyników badań tribologicznych została uzupełniona badaniami morfologii powierzchni oraz badaniami stereometrycznymi wykonanymi przed i po teście tribologicznym. Wyniki badań wykazały znaczący wpływ przygotowania podłoża na kształtowanie topografii powierzchni i właściwości tribologiczne warstw powierzchniowych.
The article presents the results of tribological measurements of an aluminium oxide layer, obtained on aluminium alloy substrate with different degrees of surface preparation, with a plastic material in sliding cooperation. The utilitarian goal of the research was to reduce an unfavourable influence of oxide layer surface roughness during the abrasive wear process of the plastic material with the layer. The purpose was achieved by determining the effect of surface preparation on the formation of the surface topography and tribological properties of oxide layer of nanoceramics. The testing pin–plane was conducted on friction– wear conditions. The analysis of the tribological results was supplemented by surface morphology studies and stereometric research made before and after the tribological test. The results showed a significant effect of surface preparation on the formation of surface topography and tribological properties of the surface coating.
Źródło:
Tribologia; 2014, 4; 9-20
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mercury-free dissolution of aluminum-based nuclear material: from basic science to the plant
Autorzy:
Crooks III, W.
Crown, J.
Dunn, K.
Mickalonis, J.
Murray, A.
Navratil, J.
Powiązania:
https://bibliotekanauki.pl/articles/148380.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
aluminum dissolution
plutonium oxide dissolution
stainless steel corrosion
mercury-free
Opis:
Conditions were optimized for the first plant-scale dissolution of an aluminum-containing nuclear material without using mercury as a catalyst. This nuclear material was a homogeneous mixture of plutonium oxide and aluminum metal that had been compounded for use as the core matrix in Mark 42 nuclear fuel. B ecause this material had later failed plutonium distribution specifications, it was rejected for use in the fabrication of Mark 42 fuel tubes, and was stored at the Savannah River Site (SRS) awaiting disposition. This powder-like material was composed of a mixture of ~80% aluminum and 11% plutonium. Historically, aluminum-clad spent nuclear fuels have been dissolved using a mercuric nitrate catalyst in a nitric acid (HNO3) solution to facilitate the dissolution of the bulk aluminum cladding. Developmental work at SRS indicated that the plutonium oxide/aluminum compounded matrix could be dissolved using boric acid-hydrofluoric acid-nitric acid as a substitute for mercury. Various mercury-free conditions were studied to evaluate the rate of dissolution of the Mark 42 compact material and to assess the corrosion rate to the stainless steel dissolver. The elimination of mercury from the dissolution process fit with waste minimization and industrial hygiene goals to reduce the use of mercury in the United States. The mercury-free dissolution technology was optimized for Mark 42 compact material in laboratory-scale tests, and successfully implemented at the plant.
Źródło:
Nukleonika; 2003, 48, 4; 163-169
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of atomic layer deposition technological parameters on optical properties and morphology of Al2O3 thin films
Autorzy:
Dobrzanski, L. A.
Szindler, M.
Hajduk, B.
Kotowicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/173801.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
thin film
aluminum oxide
atomic layer deposition
Opis:
This paper presents some results of investigations on aluminum oxide Al2O3 thin films prepared by the atomic layer deposition method on polished monocrystalline silicon. It has been described how the technological parameters of the deposition process, like the number of cycles and substrate temperature, influenced the optical properties and morphology of prepared thin films. Their physical and optical properties like thickness, uniformity and refractive index have been investigated with spectroscopic ellipsometry, atomic force microscopy and UV/vis optical spectroscopy.
Źródło:
Optica Applicata; 2015, 45, 4; 573-583
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new chemical mechanical slurry for polishing yttrium aluminium garnet material with magnesium oxide, sodium metasilicate pentahydrate and zirconium dioxide abrasive particles
Autorzy:
Duc, Le Anh
Hieu, Pham Minh
Quang, Nguyen Minh
Powiązania:
https://bibliotekanauki.pl/articles/24084631.pdf
Data publikacji:
2023
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
chemical-mechanical polishing
yttrium aluminum garnet
magnesium oxide
abrasive particles
Opis:
This work provided a new chemical-mechanical polishing mixture with MgO, sodium metasilicate pentahydrate, ZrO2 abrasive particles, and deionized water. With chemical-mechanical slurry (CMS) proposed for polishing yttrium aluminum oxide (Y3Al5O12) the surface reaction layer formed with significantly reduced hardness compared to other Y3Al5O12 materials, these products combine with MgO to form montmorillonites (3MgO–Al2O3–3SiO2–3Y2O3–5Al2O3). With this formation, the surface layer of Y3Al5O12 material becomes soft and is easily removed by ZrO2 abrasive particles under the influence of mechanical polishing, resulting in superfine surfaces generated from the proposed CMS model. The experimental results show that the surface quality with CMS proposed gives the surface quality with Ra = 0.471 nm along with the material removal rate 31 (nm/min). Surface quality is improved by 71% along with a superior material removal rate (increased by 287%) compared to silica slurry. The results show excellent polishing ability from CMS proposed for polishing Y3Al5O12 materials.
Źródło:
Journal of Machine Engineering; 2023, 23, 2; 174--185
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of oxide layers made on aluminum alloy 7075 by different methods
Charakterystyka warstw tlenkowych wytworzonych na stopie aluminium 7075 z zastosowaniem różnych metod
Autorzy:
Jędrusik, M.
Dębowska, A.
Kopia, A.
Petrzak, P.
Koclęga, D.
Kalemba-Rec, I.
Powiązania:
https://bibliotekanauki.pl/articles/263954.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
oxide layers
aluminum alloy 7075
micro-arc oxidation
phosphate coating
chemical method
warstwy tlenkowe
stop aluminium 7075
MAO
fosforanowanie
metoda chemiczna
Opis:
Aluminum and aluminum alloys are now being widely used as materials for structural applications due to a number of valuable properties. Improvement in the functional and decorative properties of aluminum can be obtained by forming an oxide layer on its surface. The aim of the present study was to produce and compare the properties of oxide layers on the surface of aluminum alloy 7075 and compare their properties. The methods that were used during the study were as follows: phosphating, micro-arc oxidation, and a chemical method involving the formation of a passive layer. The layers were subjected to corrosion tests. SEM and EDS methods were used for characterization of the received results. Also, some tests on an optical profilometer were done. It was proven that the micro-arc oxidation method allowed us to obtain a layer with the greatest thickness and highest corrosion resistance.
Glin i jego stopy są obecnie powszechnie wykorzystywanym materiałem do zastosowań konstrukcyjnych ze względu stosunek masy do wytrzymałości. Poprawę własności funkcyjnych i dekoracyjnych aluminium uzyskać można przez wytworzenie warstwy tlenku na jego powierzchni. Celem badań było wytworzenie warstw tlenkowych na podłożu ze stopu aluminium 7075 i porównanie ich właściwości. Zastosowano trzy metody: fosforanowanie, micro-arc oxidation oraz metodę chemiczną polegającą na wytworzeniu warstwy pasywnej. Otrzymane powłoki poddano testom korozyjnym oraz charakteryzowano z zastosowaniem następujących metod: SEM, EDS. Wykonano też badania na profilometrze optycznym. Metoda micro-arc oxidation pozwala na uzyskanie warstwy o największej grubości oraz najlepszej odporności na korozję.
Źródło:
Metallurgy and Foundry Engineering; 2016, 42, 3; 187-193
1230-2325
2300-8377
Pojawia się w:
Metallurgy and Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thulium-doped optical fibers for fiber lasers operating at around 2 μm
Autorzy:
Kasik, I.
Kamradek, M.
Aubrecht, J.
Peterka, P.
Podrazky, O.
Cajzl, J.
Mrazek, J.
Honzatko, P.
Powiązania:
https://bibliotekanauki.pl/articles/200843.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optical fiber
fiber laser
thulium
aluminum oxide
nanoparticles
solution doping
nanoparticle doping
Opis:
The paper deals with spectral and lasing characteristics of thulium-doped optical fibers fabricated by means of two doping techniques, i.e. via a conventional solution-doping method and via a nanoparticle-doping method. The difference in fabrication was the application of a suspension of aluminum oxide nanoparticles of defined size instead of a conventional chloride-containing solution. Samples of thulium-doped silica fibers having nearly identical chemical composition and wave guiding properties were fabricated. The sample fabricated by means of the nanoparticle-doping method exhibited longer lifetime, reflecting other observations and the trend already observed with the fibers doped with erbium and aluminum nanoparticles. The fiber fabricated by means of the nanoparticle-doping method exhibited a lower lasing threshold (by »20%) and higher slope efficiency (by »5% rel.). All these observed differences are not extensive and deserve more in-depth research; they may imply a positive influence of the nanoparticle approach on properties of rare-earth-doped fibers for fiber lasers.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 5; 981-986
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the image analysis methods for the study of Al2O3 surafce coatings
Autorzy:
Korzekwa, Joanna
Gądek-Moszczak, Aneta
Powiązania:
https://bibliotekanauki.pl/articles/103981.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
computer image analysis
aluminum oxide layer
komputerowa analiza obrazu
warstwy tlenku glinu
Opis:
Anodic oxidation of aluminum alloy in a ternary solution of SFS (sulfuric, phthalic and oxalic acids) with 30g of tungsten disulfide (WS2) powder was carried out in order to obtain the aluminum oxide layer named in article as Al2O3/WS2 coatings. The microstructures of surface of obtained coatings were investigated. The subject of the analysis was a threadlike hill structure visible on the surface of coatings as bright ridges. The computer image analysis was performed in order to study the influence of electrolysis time and temperature of acids bath on the volume fraction VV of the area of the surface with filamentous hill’s structure.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 406-411
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameter Characterization in Processing of Silver - Aluminum Based Electrical Contact Materials
Autorzy:
Praveen Kumar, S.
Parameshwaran, R.
Ananthi, A.
Jenil Jaba Sam, J.
Powiązania:
https://bibliotekanauki.pl/articles/352711.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical contactor
silver
aluminum
tin oxide
conduction
Opis:
An electrical contractor is one which plays significant role in day todays life in industries as well as in home appliances. In current scenario the materials for conducting purpose has an overwhelming research capability. Now a day the silver based electrical contact composite material have provided the potential applications in aerospace and automobile industries. Among silver based contact material the silver cadmium oxide and silver tin oxide plays a vital role in fabrication of electrical contactors. In this research an attempt has been made to study the influence of adding Aluminum with silver based electrical contact composite materials by two different processing routes namely stir-casting and powder metallurgy. Silver and aluminum matrix plays a virtual role in composite world owing to their highest conductivity. Optimum parameters were identified for attaining the maximum properties such as conductivity, hardness, density, and porosity of composition. By this better conducting property and mechanical property of the electrical contact can be improved by this system. Thus a screening test has be conducted with addition of Al with silver tin oxide compositions hence this paper aims to process the aluminum – silver based electrical contact materials by stir casting processing and powder metallurgy route and compare the results obtained.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1895-1901
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microalloying of Continuous Cast Aluminum Strip and Structural Modification Using Plastic Treatment to a 9 μm Foil (Patent no. 39762, P-377/76)
Autorzy:
Purenović, M. M.
Purenović, Jelena M.
Baralić, J. Č.
Powiązania:
https://bibliotekanauki.pl/articles/2203751.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microalloying
modified continuous cast aluminum strip
nano oxide film
corrosion stability
plasticity
superplasticity
equiaxed structure
strain hardening
surface tension
crystallization zone
dendrites
crystal twinning
Opis:
Innovative procedure of microalloying continuous cast aluminum strip, thickness 10 mm, by Be, Zr and Mn using 3C Pechiney technology (no. 39762, P-377/76), and modifying the existing parameters for strip casting and crystallization was implemented under industrial conditions with two randomly selected batches 2×8 tones, without previous selection of standardized quality of aluminum, purity Al 99.5%, obtained by electrolysis. The application of microalloying and overall structural modification of the technology resulted in obtaining nanoscale, ultra-thin, compact oxide high-gloss film with uniform surface of continuous cast strip, instead of the usual thick and porous oxide film. The outcome of microalloying the obtained equiaxed fine-grained nano/micro structure was avoiding anisotropic and dendritic microstructure of the strip, and improving deformation and plastic properties of modified continuous cast strip subjected to the technology of plastic treatment by rolling until the desired foil thickness of 9 μm was obtained. The invention of microalloying and structural modification, including multiplying effect of several components, directly or indirectly, changed numerous structurally-sensitive properties. The obtained nano/micro structure of crystal grains with equiaxed structure resulted in the synergy of undesirable <111> and inevitable <100> and <110> textures. Numerous properties were significantly enhanced: elastic modulus was improved, and intensive presence of cracks in warm forming condition was prevented due to rapid increase of the number of grains to 10000 grains/cm2 in as-cast state.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 345--357
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania laboratoryjne przyczepności stwardniałych zaczynów cementowych z dodatkiem nanotlenku glinu do wybranych formacji skalnych
Laboratory tests of adhesion of hardened cement slurries with an addition of aluminum nanoxide to various rock formation
Autorzy:
Rzepka, Marcin
Kędzierski, Miłosz
Powiązania:
https://bibliotekanauki.pl/articles/2143369.pdf
Data publikacji:
2022
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
nanotlenek glinu
zaczyn cementowy
kamień cementowy
przyczepność
cement
skała
nano aluminum oxide
cement slurry
cement stone
formation
bonding
Opis:
Artykuł przedstawia wyniki badań laboratoryjnych przyczepności zaczynów cementowych do trzech formacji skalnych, tj. rdzeni powstałych z piaskowca, mułowca oraz węgla kamiennego. Przygotowane rdzenie skalne (przed zalaniem zaczynem cementowym) poddawane były procesowi przemywania w różnych cieczach (prowadzono też badania dla tzw. rdzeni suchych). Do badań przyczepności wytypowano recepturę zaczynu cementowego zawierającą 1% nanotlenku glinu (n-Al2O3) oraz recepturę konwencjonalną (porównawczą, tj. bez udziału nanokomponentu). Badane zaczyny cementowe miały dobre parametry technologiczne, umożliwiające ich zastosowanie do uszczelniania kolumn rur okładzinowych w otworach wiertniczych o temperaturze dynamicznej około 35°C oraz ciśnieniu około 15 MPa. Po wykonaniu szeregu badań laboratoryjnych stwierdzono, że zaczyn zawierający dodatek 1% n-Al2O3 w wyraźny sposób podnosił przyczepność kamienia cementowego do formacji skalnej. Uzyskane wartości przyczepności dla zaczynu z n-Al2O3 w porównaniu z wartościami otrzymanymi dla zaczynu konwencjonalnego są około 30–40% wyższe. Analizując przyczepność kamienia cementowego (z dodatkiem i bez dodatku nanokomponentu) do różnego rodzaju formacji skalnych, należy zaznaczyć, że: najwyższą przyczepność zanotowano w przypadku piaskowca, nieco niższą – mułowca (około 80–85% wartości przyczepności uzyskanej dla piaskowca), a najniższą – węgla (około 70–75% wartości przyczepności uzyskanej dla piaskowca). Zależność ta zachodzi w podobny sposób w przypadku rdzeni „suchych”, jak i przemytych płuczką, buforem oraz cieczą przemywającą. Należy podkreślić niezwykle istotną rolę odpowiedniego procesu przemywania otworu wiertniczego przed wykonaniem zabiegu cementowania rur okładzinowych. Zastosowanie samego buforu może okazać się niewystarczające. Dodatkowe użycie odpowiednio dobranej cieczy przemywającej pozwala skutecznie usunąć resztki osadu filtracyjnego pozostającego na powierzchni formacji skalnej po jej przewierceniu, co powinno znacznie poprawić stan zacementowania otworu wiertniczego.
The article presents the results of laboratory tests of adhesion of cement slurries to three rock formations, i.e. sandstone, mudstone and hard coal cores. The prepared rock cores (before being poured over with cement slurry) were washed in various fluids (tests were also conducted for the so-called “dry” cores). The adhesion tests were carried out for two selected cement slurries recipes: cement slurry containing 1% aluminum nanoxide (n-Al2O3) and conventional cement slurry (comparative, i.e. without the addition of nanocomponents). The tested cement slurries had good technological parameters, enabling their use for sealing casing columns in boreholes with a dynamic temperature of approx. 35°C and a pressure of approx. 15 MPa. After a series of laboratory tests, it was found that the slurry containing the addition of 1% n-Al2O3 significantly increased the adhesion of the cement stone to the rock formation. The obtained values of adhesion for the n-Al2O3 slurry, compared to the values obtained for the conventional slurry, are about 30–40% higher. When analyzing the results of adhesion of cement stone (with and without the addition of a nanocomponent) to various types of rock formations, it is stated that the highest values of adhesion was obtained for sandstone, slightly lower for mudstone (about 80–85% of the adhesion value obtained for sandstone) and the lowest for coal (about 70–75% of the adhesion value obtained for sandstone). This dependence is similar in the case of “dry” cores and those washed with mud, spacer fluid and washing fluid. It should be emphasized that the proper process of washing the borehole is very important prior to cementing the casing. The use of a spacer fluid alone may not be sufficient. The additional use of a properly selected washing liquid increases the mud-cake removal efficiency, which should significantly improve the quality of borehole cementing.
Źródło:
Nafta-Gaz; 2022, 78, 1; 22-30
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Możliwości zastosowania nanotlenku glinu w zaczynach cementowych przeznaczonych do uszczelniania rur okładzinowych w otworach wiertniczych
The possibility of using of nano aluminum oxide in cement slurries for sealing casing in boreholes
Autorzy:
Rzepka, Marcin
Kędzierski, Miłosz
Powiązania:
https://bibliotekanauki.pl/articles/1834133.pdf
Data publikacji:
2020
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
nanotlenek glinu
nano-Al2O3
zaczyn cementowy
kamień cementowy
wiązanie zaczynu
wytrzymałość mechaniczna
nano aluminum oxide
cement slurry
cement sheath
cement setting
mechanical strength
Opis:
The article presents compositions and test results for cement slurries formulations containing from 1% to 5% of nano aluminum oxide (n-Al2O3) for sealing the casing columns in boreholes with dynamic temperatures of about 30°C and 60°C. Laboratory tests of cement slurries were carried out at Oil and Gas Institute - National Research Institute. The densities of tested slurries ranged from 1,820 to 1,920 kg/m3 , and were prepared on the basis of Portland cement CEM I 42,5 and class G oil well cement. Cement slurries had thickening times properly matched to given geological and technical conditions. For slurries tested at lower temperatures, particular attention was paid to the gelling and setting process of cement slurries. These parameters play a key role in limiting possible gas migrations from shallow gas accumulations. They were selected so that the gelling and setting process could be carried out in a sufficiently short time. At higher temperatures, the focus was on developing cement slurry formulations with increased mechanical strength and a tight and compact microstructure. Cement slurry formulations with very good technological parameters were developed, which after curing (after 28 days of hydration) had very high values of compressive strength, reaching up to 40 MPa. Such high compressive strength values are extremely difficult to obtain with conventional cement slurries. Scanning electron microscope images of cement samples also confirm extremely compact microstructure of the samples with nano-SiO2. In addition to the photographs of base cement stones, which show pores, microscopic images of samples with the addition of 3% n-Al2O3 are presented, where we observe a compact cement matrix with very low permeability. Furthermore, samples containing n-Al2O3 were characterized by a very low content of capillary pores. Pores of the smallest size (below 100 nm) constituted the vast majority of the total number of pores. Improvement of cement matrix tightness by reducing the amount of pores that can transport the reservoir medium to approx. 1.5% means that cement slurry formulas containing nano aluminum oxide can be successfully used in the process of cementing casing strings in boreholes.
Źródło:
Nafta-Gaz; 2020, 76, 1; 46-56
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Abrasion Resistance of S235, S355, C45, AISI 304 and Hardox 500 Steels with Usage of Garnet, Corundum and Carborundum Abrasives
Autorzy:
Szala, Mirosław
Szafran, Michał
Macek, Wojciech
Marchenko, Stanislav
Hejwowski, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/103045.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
abrasion
wear resistance
dry sand-rubber wheel test
garnet
aluminum oxide
silicon carbide
steel
hardness
microstructure
odporność na ścieranie
test koła suchy piasek-guma
granat
tlenek glinu
węglik krzemu
stal
twardość
mikrostruktura
Opis:
The steel presents a wide field of application. The abrasive wear resistance of steel relies mainly on the microstructure, hardness as well as on the abrasive material properties. Moreover, the selection of a abrasion-resistant grade of steel still seems to be a crucial and unsolved problem, especially due to the fact that the actual operating conditions can be affected by the presence of different abrasive materials. The aim of this work was to determine the effect of different abrasive grit materials i.e. garnet, corundum and carborundum on the abrasive wear result of a commonly used in industry practice steels i.e. S235, S355, C45, AISI 304 and Hardox 500. The microstructure of the steel was investigated using light optical microscopy. Moreover, hardness was measured with Vickers hardness tester. Additionally, the size and morphology of the abrasive materials were characterized. The abrasion tests were conducted with the usage of T-07 tribotester (dry sand rubber wheel). The results demonstrate that the hardness and structure of steels and hardness of abrasive grids influenced the wear results. The abrasive wear behavior of steels was dominated by microscratching and microcutting wear mechanisms. The highest mass loss was obtained for garnet, corundum, and carborundum, respectively. The usage of various abrasives results in different abrasion resistance for each tested steel grade. The AISI 304 austenitic stainless steel presents an outstanding abrasive wear resistance while usage of corundum and Hardox 500 while using a garnet as abrasive material. The C45 carbon steel was less resistant than AISI 304 for all three examined abrasives. The lowest resistance to wear in garnet and carborundum was obtained for the S235JR and S355J2 ferritic-perlitic carbon steels and in corundum for Hardox 500 which has tempered martensitic structure.
Źródło:
Advances in Science and Technology. Research Journal; 2019, 13, 4; 151-161
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Al2O3/4H-SiC and Al2O3/SiO2/4H-SiC MOS structures
Autorzy:
Taube, A.
Guziewicz, M.
Kosiel, K.
Gołaszewska-Malec, K.
Król, K.
Kruszka, R.
Kamińska, E.
Piotrowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/953063.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum oxide
MOS
silicon carbide
4H-SiC
high-K dielectrics
tlenek glinu
węglik krzemu
dielektryki high-k
Opis:
The paper presents the results of characterization of MOS structures with aluminum oxide layer deposited by ALD method on silicon carbide substrates. The effect of the application of thin SiO2 buffer layer on the electrical properties of the MOS structures with Al2O3 layer has been examined. Critical electric field values at the level of 7.5–8 MV/cm were obtained. The use of 5 nm thick SiO2 buffer layer caused a decrease in the leakage current of the gate by more than two decade of magnitude. Evaluated density of trap states near the conduction band of silicon carbide in Al2O3/4H-SiC MOS is about of 1×1013 eV−1cm−2. In contrast, the density of the trap states in the Al2O3/SiO2/4H-SiC structure is lower about of one decade of magnitude i.e. 1×1012 eV−1cm−2. A remarkable change in the MOS structure is also a decrease of density of electron traps located deeply in the 4H-SiC conduction band below detection limit due to using of the SiO2 buffer layer.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 3; 537-551
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

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