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Wyszukujesz frazę "dry sand" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Experimental study of the shear resistance of granular material: influence of initial state
Autorzy:
Flitti, A.
Della, N.
Verástegui Flores, R. D.
Powiązania:
https://bibliotekanauki.pl/articles/282069.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dry sand
fine content
water content
grain size
depositional method
Opis:
The shear strength of sand and its mechanical properties can be affected by numerous parameters. This work presents an experimental investigation which aims to study the influence of the fines content, the depositional method and the grain size on the shear strength of Chlef sand. Tests were conducted with the shear box on two types of soil, the natural sand and the clean sand-silt mixture. Dense samples (Dr = 88%) were reconstituted through dry deposition for each type of the material. An additional series of tests was carried out on a medium dense natural sand (Dr = 52%) prepared by dry and wet (w = 3%) deposition methods. All specimens were subjected to normal stresses of 100 kPa, 200 kPa and 300 kPa and there was no immersion of water. The tests results show that the behavior of sand can be affected by three parameters, the fines content, the deposition method and the particle size. The maximum shear stress and the friction angle decrease as the fines content increases, the initial water content increases, the effective grain size diameter decreases and the uniformity coefficient increases. The cohesion intercept increases with the increasing fines content and decreasing initial water content. Overall, the samples prepared by the dry deposition method show more resistance than those prepared by the wet deposition method. The results obtained are generally in agreement with the previous research on drained and undrained saturated sand in the literature.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 523-533
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Abrasive Wear Mechanisms of S235JR, S355J2, C45, AISI 304, and Hardox 500 Steels Tested Using Garnet, Corundum and Carborundum Abrasives
Autorzy:
Szala, Mirosław
Szafran, Michał
Matijošius, Jonas
Drozd, Kazimierz
Powiązania:
https://bibliotekanauki.pl/articles/2201922.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
abrasion
wear resistance
dry sand-rubber wheel test
tribology
steel
wear mechanism
roughness analysis
failure analysis
Opis:
Wear resistance is one of the main indicators of the reliability of machine parts. The selection of wear-resistant material should consider the operational environment and specific types of abrasive material. The steel abrasive wear resistance depends not only on its hardness and microstructure but also on the abrasive material's properties, such as hardness and particle morphology. This work aimed to determine abrasion wear mechanisms of a set of steels, i.e., S235, S355, C45, AISI 304 and Hardox 500, abraded by different types of grit i.e. garnet, corundum and carborundum. The abrasion tests were conducted using T-07 tribometer (rubber wheel method). Wear traces were examined with a scanning electron microscope (SEM), and a contact profilometer. SEM analysis revealed that apart from Hardox 500, ploughing and microfatigue were the dominant wear mechanisms. Microcutting was the main wear mechanism for Hardox 500 tested with carborundum (SiC). The highest mass loss was usually obtained for carborundum. The lowest wear resistance in garnet and carborundum was obtained for the S235JR and S235J2 steels and Hardox 500 tested with corundum. The effect of steel microstructure on the wear mechanism has been confirmed. AISI 304 austenitic steel abraded by carborundum grit, presented outstanding roughness parameters: Ra, Rz, RSm, Rk, Rvk and Rpk than other steels tested with carborundum. Steel hardness affects the morphology of the wear trace reducing the Ra and Rz roughness parameters. The effect of abrasive hardness and grain morphology on abraded surfaces has been stated. Contrary to fine grains of the hardest carborundum, coarse garnet grains caused high roughness parameters (Rk, Rpk and Rvk) determined in wear trace.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 2; 147--160
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands
Autorzy:
Ignaszak, Z.
Prunier, J. B.
Powiązania:
https://bibliotekanauki.pl/articles/380085.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chromite sand
magnetic recuperation
neodymium magnets
furan sand dry
reclamation
ferrous alloys
heavy castings
Opis:
The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium). The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.
Źródło:
Archives of Foundry Engineering; 2016, 16, 3; 162-166
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of abrasive-wear resistance of Brinar and Hardox steels
Analiza porównawcza odporności na zużywanie ścierne stali Brinar i Hardox
Autorzy:
Białobrzeska, B.
Konat, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/187927.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
abrasion wear
low-alloy boron steel
dry sand-rubber wheel test
Brinar
Hardox
zużywanie ścierne
niskostopowe stale z borem
test odporności na zużywanie ścierne
Opis:
One of the most important problems encountered during operation of machine parts exposed to abrasive action is their wear. In addition, these parts often work under dynamic loads, so their satisfactory ductility is also required. A combination of these apparently opposing properties is to a large degree possible in low-alloy martensitic steels containing boron. These steels are manufactured by numerous metallurgical concerns, but their nomenclature is not standardised and they appear under names given by the manufacturers, and their specifications are available in commercial information materials only. Till now, Hardox steels have been objects of great interest but, with regard to the continuous development of materials engineering, the created material database requires regular supplementation. To that end, two grades of steels from this group, Brinar 400 and Brinar 500, were subjected to comparative analysis of their abrasive-wear resistance in relation to properties of competitive grades Hardox 400 and Hardox 500. Abrasive-wear resistance tests were carriedout in laboratory conditions using a tribotester T-07. In addition, to identify the main wear mechanisms, worn surfaces of the specimens were examined with use of a scanning electron microscope.
Jednym z najważniejszych problemów, na jaki napotyka się podczas eksploatacji elementów maszyn narażonych na działanie masy ściernej, jest ich zużywanie. Dodatkowo elementy te pracują często w warunkach obciążeń o charakterze dynamicznym, stąd wymaga się od nich również zadowalającej ciągliwości. Połączenie tych, na pierwszy rzut oka, przeciwstawnych właściwości było w dużej mierze możliwe w niskostopowych, martenzytycznych stalach z borem. Stale te są produkowane przez wiele koncernów hutniczych, ale nazewnictwo ich nie jest znormalizowane i występują pod nazwami nadanymi im przez producentów, a dane o nich dostępne są jedynie w materiałach komercyjnych. Do tej pory intensywnie zajmowano się stalami typu Hardox, ale w związku z ciągłym rozwojem inżynierii materiałowej stworzona baza materiałowa wymaga stałych uzupełnień. W tym celu analizie porównawczej, pod względem odporności na zużywanie ścierne, poddano kolejne dwa gatunki należące do tej grupy stali – Brinar 400 i Brinar 500, których właściwości odniesiono do konkurencyjnych stali Hardox 400 i Hardox 500. Badania odporności na zużywanie ścierne tych stali zrealizowano w warunkach laboratoryjnych za pomocą tribotestera T-07. Dodatkowo, w celu zidentyfikowana głównych mechanizmów zużywania, za pomocą elektronowego mikroskopu skaningowego (SEM) zostały przeprowadzone badania wyeksploatowanych powierzchni próbek analizowanych stali.
Źródło:
Tribologia; 2017, 272, 2; 7-16
0208-7774
Pojawia się w:
Tribologia
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:
Influence of soil fabrics and stress state on the undrained instability of overconsolidated binary granular assemblies
Autorzy:
Mahmoudi, Y.
Taiba, A. C.
Hazout, L.
Baille, W.
Belkhatir, M.
Powiązania:
https://bibliotekanauki.pl/articles/178902.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
instability line
dry funnel pluviation
wet deposition
overconsolidation ratio
sand-silt mixtures
Opis:
The instability of saturated granular soils in field conditions generates drastic collapse in terms of runoff deformation because of its failing to sustain naturally applied loading conditions such as earthquakes, wave actions and vibrations. The objective of this laboratory investigation is to study the effects of the depositional methods, overconsolidation ratio (OCR) and confining pressure on the undrained instability shear strength of medium dense (Dr = 52%) sand-silt mixtures under static loading conditions. For this purpose, a series of undrained monotonic triaxial tests were carried out on reconstituted saturated silty sand samples with fines content ranging from 0% to 40%. Three confining pressures were used (P’c = 100, 200 and 300 kPa) in this research. The sand-silt mixture samples were prepared using two depositional methods, dry funnel pluviation (DFP) and wet deposition (WD), and subjected to two OCRs (1 and 2). The obtained instability lines and friction angles indicate that the funnel pluviated samples exhibit strain hardening compared to the wet deposited samples and that normally consolidated and overconsolidated wet deposited clean sandy samples were very sensitive to static liquefaction. The test results also indicate that the instability friction angle increases with the increase in the OCR expressing soil dilative character tendency increase. The instability friction angle decreases with the increase in the fines content for DFP and the inverse tendency was observed in the case of WD.
Źródło:
Studia Geotechnica et Mechanica; 2018, 40, 2; 96-116
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ stosowania krzemu oraz rodzaju podłoża na plonowanie i skład chemiczny pomidora
The effect of silicon application and type of medium on yielding and chemical composition of tomato
Autorzy:
Jarosz, Z.
Powiązania:
https://bibliotekanauki.pl/articles/11542973.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
plant nutrition
silicon
application
medium type
rockwool
sand
straw
yielding
chemical composition
tomato
dry weight
vitamin C
total sugar
nutrient
Opis:
Fertilization of plants with silicon is particularly justified in soilless culture in which the roots of plants cannot use silicon resources in the soil. Silicon is the only element that does not harm plants when taken up in excessive amounts and its use in plant fertilization improves the yielding ability of plants and their resistance to various stress factors. The effectiveness of silicon application in growing plants is strictly dependent on both the source of this element, plant species and cultivars. The aim of this study was to determine the effect of root application of colloidal silicon as well as of three types of growing media of different silica content and varying ability to release orthosilicate monomers (rockwool, sand, straw) on yield and chemical composition of greenhouse tomato. The research was conducted in greenhouse in the period 2008–2009. Tomato was grown in an extended growth cycle (22 clusters) using a drip irrigation and fertilization system with closed nutrient solution circulation. Tomato plants fertigated with the nutrient solution enriched with silicon showed significantly higher total fruit yield (15.98 kg·plant-1) compare to plant grown in control treatments. In the studies not found significant differences in total and marketable yield as well as in mean fruit weight between plants grown in rockwool and straw mediums. The total fruit yield of tomato plants grown in sand was lower compared to rockwool-grown plants. The fruit of tomato grown in sand was shown to have more dry matter (5.52%), total sugars (2.58% FR.W.) and potassium (4.19% DW) compared to rockwool culture as well as significantly the highest amount of silicon. The leaves of tomato fertilized with the silicon-enriched nutrient solution contained more silicon as well as less manganese and zinc compared to control plants. Fertilization of plants with silicon is particularly justified in soilless culture in which the roots of plants cannot use silicon resources in the soil. Silicon is the only element that does not harm plants when taken up in excessive amounts and its use in plant fertilization improves the yielding ability of plants and their resistance to various stress factors. The effectiveness of silicon application in growing plants is strictly dependent on both the source of this element, plant species and cultivars. The aim of this study was to determine the effect of root application of colloidal silicon as well as of three types of growing media of different silica content and varying ability to release orthosilicate monomers (rockwool, sand, straw) on yield and chemical composition of greenhouse tomato. The research was conducted in greenhouse in the period 2008–2009. Tomato was grown in an extended growth cycle (22 clusters) using a drip irrigation and fertilization system with closed nutrient solution circulation. Tomato plants fertigated with the nutrient solution enriched with silicon showed significantly higher total fruit yield (15.98 kg·plant-1) compare to plant grown in control treatments. In the studies not found significant differences in total and marketable yield as well as in mean fruit weight between plants grown in rockwool and straw mediums. The total fruit yield of tomato plants grown in sand was lower compared to rockwool-grown plants. The fruit of tomato grown in sand was shown to have more dry matter (5.52%), total sugars (2.58% FR.W.) and potassium (4.19% DW) compared to rockwool culture as well as significantly the highest amount of silicon. The leaves of tomato fertilized with the silicon-enriched nutrient solution contained more silicon as well as less manganese and zinc compared to control plants.
żywienie roślin krzemem jest szczególnie uzasadnione w systemie bezglebowym, w którym korzenie roślin nie mogą korzystać z zasobów tego pierwiastka znajdującego się w glebie. Krzem to jedyny pierwiastek nieszkodzący roślinom przy nadmiernym pobraniu, a jego stosowanie w żywieniu poprawia plonowanie roślin oraz ich odporność na różnorodne czynniki stresowe. Efektywność stosowania krzemu w uprawie roślin jest ściśle uzależniona zarówno od źródła tego pierwiastka, jak i od uprawianego gatunku i odmiany. Celem badań było określenie wpływu dokorzeniowego stosowania krzemu koloidalnego oraz trzech podłoży o zróżnicowanej zawartości krzemionki i różnej zdolności uwalniania monomerów ortokrzemianowych (wełna mineralna, piasek, słoma) na plonowanie i skład chemiczny pomidora szklarniowego. Badania przeprowadzono w latach 2008–2009 w szklarni. Uprawę prowadzono w cyklu wydłużonym (22 grona) z wykorzystaniem kroplowego systemu nawożenia i nawadniania z zamkniętym obiegiem pożywki. W badaniach wykazano istotnie większy plon ogólny owoców fertygowanych pożywką wzbogaconą w krzem (15,98 kg·roślina-1) w porównaniu z roślinami uprawianymi w obiektach kontrolnych. Nie stwierdzono istotnych różnic w plonie ogólnym i handlowym, jak również w średniej masie owoców z roślin uprawianych w wełnie mineralnej i w słomie. Plon ogólny pomidorów uprawianych w piasku był mniejszy w porównaniu z roślinami uprawianymi w wełnie mineralnej. W owocach pomidora uprawianego w piasku stwierdzono więcej suchej masy (5,52%), cukrów ogółem (2,58% św. m.) i potasu (4,19% s.m.) w porównaniu z wełną mineralną oraz istotnie najwięcej krzemu. Liście pomidora nawożonego pożywką wzbogaconą w krzem zawierały więcej krzemu oraz mniej manganu i cynku w porównaniu z roślinami kontrolnymi.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2014, 13, 4; 171-183
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synergy of practical knowledge of molding sands reclamation in heavy casting foundry of iron alloys
Autorzy:
Ignaszak, Z.
Prunier, J. B.
Powiązania:
https://bibliotekanauki.pl/articles/379704.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
furan molding sand
dry mechanical reclamation
iron alloy foundry
heavy casting
lifetime
furan sand
thermo mechanical database
masa formierska furanowa
sucha regeneracja mechaniczna
stop żelaza
odlew ciężki
trwałość
baza danych termomechaniczna
Opis:
The paper summarizes research realized by the author in laboratory and industrial conditions (foundries of cast steel and cast iron, castings up to 50 tons) on the effects of the chemically hardened molding sands regeneration using hard/soft rubbing in the dry reclamation. A reference was simultaneously made to advisability of application of the thermal regeneration in conditions, where chromite amount in the circulating (reclaimed) molding sand goes as high as above ten percent. An advisability of connecting standard and specialized methods of examination of the reclaimed sands and molding sands made using it was pointed out. A way of application of studies with the Hot Distortion Plus® method modified by the author for validation of modeling of the thermo-dynamic phenomena in the mold was shown.
Źródło:
Archives of Foundry Engineering; 2013, 13, 3; 30-36
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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