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Tytuł:
Determination of variable pseudo-viscosity coefficients for oils with the Rivlin - Ericksen properties
Autorzy:
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/247350.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
pseudo-viscosity coefficients
apparent viscosity
Rivlin-Ericksen equation
viscosity curves
Opis:
Modern oils, that lubricate the sliding friction pairs, contain more and more additives. These additives change the oil properties to the non-Newtonian. Furthermore, the friction and wear products and also the products of combustion in internal combustion engines, result in a change of the oil properties, from Newtonian to the non-Newtonian. Frequently, researchers suggest to use so-called „smart fluids”, for example, the ferro-oils as lubricants of sliding friction pairs exposed to strong magnetic fields or the absence of gravity. The ferro-oils are also characterized by the non-Newtonian properties. The viscosity characteristics of these oils are described rather well by the Rivlin-Ericksen constitutive equation. The Rivlin-Ericksen constitutive equation contains the coefficients, which are difficult to estimate or determine experimentally. One of the possibilities to determine these coefficients is the method proposed by Prof. K. Wierzcholski [12]. This method requires the experimental results of dynamic viscosity changes as a function of shear rate. The measurements of dynamic viscosity should be conducted for the widest possible range of shear rates. Then, using the viscosity curves and nonlinear system of equations, the auxiliary coefficients are determined. These coefficients generate the equations that describe the variable pseudo-viscosity coefficients. Not all oils have an intensive exponential character of viscosity changes in dependence on shear rate. In these cases it is possible to determine the constant coefficients of pseudo-viscosity [1, 3, 7, 8]. This paper presents the examples of determination of the variable pseudo-viscosity coefficients for the selected lubricating oils and ferro-oils.
Źródło:
Journal of KONES; 2013, 20, 1; 201-208
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of measuring process properties on phosphate rock slurry rheology based on Brookfield method
Autorzy:
Chen, Aoao
Zhang, Qin
Powiązania:
https://bibliotekanauki.pl/articles/2175436.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
phosphate rock
grinding
concentration
rheological properties
apparent viscosity
Opis:
This research aims to explore how the flotation process conditions influence the rheological properties of phosphate rock slurry. The apparent viscosity of phosphate rock slurry was measured by Brookfield DVNext rheometer. Different mineral types, grinding time, slurry mass concentration and reagent systems were adopted to study the viscosity behavior of phosphate rock slurry. The results showed that under the same conditions, the apparent viscosity of apatite and dolomite slurry was basically the same, and the apparent viscosity of the slurry after mixing the two minerals was basically the same as that of single mineral. For the same slurry concentration, the mineral particle size had a significant effect on the rheological behavior of the slurry, and its apparent viscosity increased exponentially with the decrease of particle size. In addition, phosphate rock slurry showed shear thickening fluids characteristics when the slurry concentration is 20%-40%, but changed to pseudoplastic fluid at high concentration (60%). Sulfuric acid as pH regulator and inhibitor had little effect on the rheology of slurry; when GJBW and NaOL were added as collectors, the rheology of slurry changed, and the effect of GJBW was more obvious.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 156202
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Różnorodność zachowań reologicznych wodnych roztworów wybranych hydrokoloidów spożywczych podczas mieszania długotrwałego
Rheological behavior diversity during long-lasting mixing of water solutions of selected food-type hydrocolloids
Autorzy:
Kabziński, M.
Ptaszek, P.
Ptaszek, A.
Grzesik, M.
Powiązania:
https://bibliotekanauki.pl/articles/2073219.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
mieszanie
hydrokoloidy
lepkość pozorna
mixing
hydrocolloids
apparent viscosity
Opis:
Przedstawiono właściwości reologiczne roztworów wybranych hydrokoloidów spożywczych poddawanych ścinaniu w warunkach mieszania długotrwałego. Roztwory karboksymetylocelulozy, gumy ksantanowej oraz karagenu mieszano w czasie pięciu godzin w warunkach wzrastających obrotów mieszadła. W eksperymencie zastosowano mieszadła: kotwicowe, ramowe i wstęgowe. Lepkość pozorną obliczono korzystając z zasad reometrii mieszadłowej. Wyniki badań potwierdziły odmienność zachowań teologicznych omawianych hydrokoloidów mieszanych przy użyciu mieszadeł o różnej geometrii oraz pozwoliły na określenie warunków występowania zmian lepkości pozornej w funkcji czasu.
Differences in rheological behavior between solutions of selected food-type hydrocolloids undergoing long-lasting shear mixing are presented. Solutions of carboxymethylcellulose, xanthan gum and carrageenan were subjected to mixing for five hours under conditions of increasing stirrer rotational frequency. The anchor, frame and ribbon stirrers were applied in experiments. Apparent viscosity was calculated using the principles of mixer rheometry. The results confirmed differences in rheological behavior of hydrocolloids mixed using mixers of different geometry and allowed to define conditions of changes of apparent viscosity as a function of time.
Źródło:
Inżynieria i Aparatura Chemiczna; 2016, 5; 182--185
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of physical and physico-chemical factors on pulp rheology of smithsonite
Autorzy:
Shang, Yanbo
Sun, Chuanyao
Powiązania:
https://bibliotekanauki.pl/articles/10933093.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
smithsonite
pulp rheology
apparent viscosity
yield stress
particle agglomerate
Opis:
Pulp rheology is an important factor affecting flotation. The effects of particle size (150-74 μm, 74-38 μm, 38-23 μm, -23 μm), pulp density (11.76%-34.78%), pH (5.3-12.4), collector concentration (25-500 mg/dm3), and stirring intensity (400-900 rpm) on the rheology of smithsonite, kaolinite, quartz, and calcite minerals were investigated in detail. Additionally, the agglomerate morphology of particles was observed by a polarizing microscope. The results showed that as the mineral particle size decreased and pulp density increased, the apparent viscosity and yield stress of the pulp increased. Especially the fine mineral particles (-23 μm) presented a higher apparent viscosity and yield stress. The order of apparent viscosity and yield stress for the minerals from large to small was: kaolinite>calcite>smithsonite>quartz under different pH values, the collector concentrations, and stirring intensities. In the presence of collector of octadecylamine, smithsonite, kaolinite, and calcite particles could form aggregates, especially smithsonite particles presented obvious agglomeration with large particle size and compact network structure. The agglomeration effect of calcite and kaolinite particles were weaker than that of smithsonite. The particle agglomeration resulted in the increase of the apparent viscosity and yield stress of the pulp. Quartz particles did not form clusters, hence the pulp’s apparent viscosity and yield stress were the lowest. The research on the changes in rheological properties of the pulp will hopefully provide some guidance for future flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 157244
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of hindered amine light stabilizers on the resistance of polypropylene towards ionizing radiation
Autorzy:
Przybytniak, G.
Mirkowski, K.
Rafalski, A.
Nowicki, A.
Legocka, I.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/148686.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
polypropylene
stabilizers
HALS
electron beam
apparent viscosity
nucleation agent
Opis:
The influence of hindered amine light stabilizers (HALSs) on physical and mechanical properties of irradiated and non-irradiated isotactic polypropylene (PP) was studied. The stabilizers under investigation were: Tinuvin 765 (T765) and Tinuvin 622 (T622) - derivatives of 1,2,2,6,6-pentamethyl piperidine and Chimassorb 944 (C944) - a derivative of 2,2,6,6-tetramethyl piperidine. It was found that the stabilizers reduce the amount of peroxyl radicals in the amorphous phase of PP. The irradiation with electron beam causes a drop of apparent viscosity both in the original and in the modified PP however the effect is smaller in the presence of HALSs. Admixture of T622 and T765 stabilizers increases the crystallization temperature of non-irradiated PP by about 8 10°C (measured by DSC) what results from the facilitated formation of a large number small microcrystals. It was concluded that HALSs initiate two opposite tendencies - chemical protection against damage initiated by free radicals and, simultaneously, physical enhancement of sensitivity towards irradiation by the increase of nucleation density. In the studied systems, the presence of maleic anhydride does not improve compatibility between the polymeric matrix and HALSs.
Źródło:
Nukleonika; 2005, 50, 4; 153-159
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of particle properties on rheology of low-concentration coal suspensions
Autorzy:
Hou, Jinying
Ma, Xiaomin
Fan, Yuping
Dong, Xianshu
Yao, Suling
Powiązania:
https://bibliotekanauki.pl/articles/1845222.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
apparent viscosity
coal suspension
particle property
hydrophobicity
effective volume
Opis:
In wet coal preparation, the products of some processes are transported as low-concentration suspensions. Their rheology is greatly affected by the properties of the coal particles that result from the formation and weathering during preparation. In this study, the properties of coal particles, including volumetric properties (i.e., solids content, granularity, and clay mineral fraction) and surface characteristics (i.e., dynamic potential, degree of coalification, and degree of surface oxidization), were studied to determine their effects on the apparent viscosity of low-concentration coal suspensions. With increasing solids content and smaller particle size in the suspension, the interactions between the coal particles became stronger due to the increased particle content, thus increasing the coal suspension’s apparent viscosity. Adding clay minerals to the suspension gradually changed its composition and structure and increased its viscosity. The dynamic potential of the coal particles and inter-particle electrostatic repulsive forces were reduced with the addition of Ca2+ ions, and the coal particles collided and aggregated, which increased the apparent viscosity of the suspension. For coal with a low degree of coalification or coal had been oxidized by a hydrogen peroxide solution, the suspension of the hydrophilic coal particles was associated with a lower apparent viscosity than that of highly hydrophobic solids, which tended to aggregate and form flocculent masses.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 984-995
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mieszanie wolnoobrotowe roztworów karagenu – wpływ na właściwości reologiczne ®
Low-speed agitating of carrageenan solutions – impact on rheological properties®
Autorzy:
Kabziński, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/227668.pdf
Data publikacji:
2019
Wydawca:
Wyższa Szkoła Menedżerska w Warszawie
Tematy:
mieszanie wolnoobrotowe
lepkość pozorna
karagen
low-speed agitating
apparent viscosity
carrageenan
Opis:
Artykuł przedstawia wpływ stężenia hydrokoloidu na kształtowanie się charakteru reologicznego wodnych roztworów karagenu w warunkach mieszania wolnoobrotowego. Badany płyn potraktowano jako modelowy układ spożywczy imitujący rzeczywiste środki spożywcze o konsystencji żelu twardego. Operację mieszania prowadzono w warunkach skokowo zmiennej liczby obrotów mieszadła. Na podstawie danych pomiarowych wyznaczono parametry równania Herschela- Bulkleya: granicę płynięcia, współczynnik konsystencji oraz wskaźnik płynięcia. Przeanalizowano nieliniowość zależności opisanych powyżej parametrów oraz zmieniające się wraz ze stężeniem karagenu efekty zależności naprężenia ścinającego od czasu mieszania.
The article presents the effect of hydrocolloid concentration on the rheological character of aqueous carrageenan solutions under low-speed agitating. The test fluid was treated as a model food system imitating real foodstuffs with the consistency of hard gel. The mixing operation was carried out under the conditions of a rapidly variable stirrer speed. Based on the measurement data, the parameters of the Herschel -Bulkley equation were determined: flow limit, consistency coefficient and flow index. Non-linearities of dependences of the parameters described above were analyzed as well as the effects of shear stress from mixing time changing along with the carrageenan concentration.
Źródło:
Postępy Techniki Przetwórstwa Spożywczego; 2019, 1; 52-54
0867-793X
2719-3691
Pojawia się w:
Postępy Techniki Przetwórstwa Spożywczego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ zawartości suchej masy na właściwości reologiczne soku marchwiowego
The impact of dry matter content on the rheological properties of carrot juice
Autorzy:
Kobus, Z.
Kusińska, E.
Guz, T.
Powiązania:
https://bibliotekanauki.pl/articles/292099.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
sok marchwiowy
lepkość pozorna
właściwości reologiczne
carrot juice
apparent viscosity
rheological properties
Opis:
W pracy badano wpływ zawartości suchej masy na właściwości reologiczne soku marchwiowego. Właściwości te określano za pomocą lepkościomierza Brookfield, stosując wrzeciono S-62 i prędkości obrotowe z zakresu od 6 do 60 min-1. Pomiary przeprowadzono dla pięciu stężeń: 9,8%, 6,82%, 4,83%, 2,41% i 1,2% w temperaturze 22°C. Otrzymane wyniki wykazały, że wraz z rozcieńczaniem soku marchwiowego zmniejsza się jego lepkość oraz zmienia charakter reologiczny z płynu pseudoplastycznego na niutonowski.
The work presents the study on the impact of dry matter content on the rheological properties of carrot juice. The researchers were determining these properties with the Brookfield viscometer, using the S-62 spindle and applying rotational speed ranging from 6 to 60 min-1. The measurements were carried out for five concentration values: 9.8%, 6.82%, 4.83%, 2.41% and 1.2% at temperature of 22°C. The obtained results have proven that carrot juice diluting is followed by reduction in its viscosity and rheological character change from pseudoplastic fluid to the Newtonian fluid.
Źródło:
Inżynieria Rolnicza; 2011, R. 15, nr 4, 4; 121-126
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of pH and stabilization time on apparent viscosity of aqueous dispersion of wholemeal barley flour
Autorzy:
Zarzycki, P.
Wirkijowska, A.
Sobota, A.
Sykut-Domanska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2083676.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
apparent viscosity
barley
dietary fibre
pH
(1→3)
(1→4)–β–D glucans
INTRODUCTION
Opis:
The effect of stabilization time (0.5-3 h), pH (1.5-12), and shear rate (200-1200 s–1) on the apparent viscosity of the aqueous dispersion of wholemeal barley flour was determined. Six barley flours with different (1→3), (1→4)β–D–glucan contents were used in this study. The results revealed the significant effect of pH on apparent viscosity, but no unidirectional relationships were observed. The highest values of apparent viscosity were obtained at the highest pH (pH 12). An increase in the apparent viscosity of the barley flour dispersion with the passage of time was observed. A significant linear correlation between the apparent viscosity of aqueous dispersions of wholemeal barley flour and the content of (1→3), (1→4)–β–D glucans in wholemeal barley flour was found. These results suggest that measurements of apparent viscosity may be used to rapidly estimate (1→3), (1→4)–β–D glucan content in barley wholemeal flour. The content of (1→3), (1→4)–β–D glucans may be determined with an accuracy of 87% by the apparent viscosity of the barley flour dispersion (R2 = 0.87) with the following measurement conditions: 10% w/w wholemeal barley flour water dispersions, shear rate 1200 s–1, pH 12, 1.5-2 h time stabilization.
Źródło:
Acta Agrophysica; 2019, 26, 2; 19-28
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rheological properties of chitosan blends with partially hydrolyzed polyacrylamide in different solvents
Autorzy:
Lewandowska, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/1035377.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
apparent shear viscosity
chitosan
polyacrylamide
polymer blends
rheological properties.
Opis:
In the present paper, the results of rheological measurements in solutions of chitosan (Ch) with partially hydrolyzed polyacrylamide (HPAM) are presented. Aqueous acetic acid, lactic acid and aqueous acetic acid/NaCl were used as solvents for chitosan, HPAM and Ch/HPAM solution blends. The criterion of miscibility of solution blends, based on the additivity rule of apparent shear viscosity (ηa) has been discussed. The rheological parameters from power law (Ostwald de Waele model) and activation energy of viscous flow (Ea) have been calculated from the flow curves and Arrhenius plots, respectively. It was found that studied polymer solutions exhibited the non-Newtonian behaviour with shear-thinning and/or shear-thickening areas. The final result depends on the thermodynamic goodness of the solvent and on the blend composition.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2012, 17; 53-62
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 23

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