Wyniki wyszukiwania - Biblioteka Nauki

1

Sposoby obliczania lepkości wodno-olejowych mieszanin emulsyjnych

100%

Hapanowicz J. , Czernek K. , Pendyk B.

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tom Nr 6

13-17

PL

Dokonano przeglądu, podawanych w literaturze, sposobów obliczania lepkości mieszanin emulsyjnych. Podjęto próbę oceny możliwości wykorzystania tych metod do opisu lepkości skoncentrowanych wodno—olejowych mieszanin emulsyjnych. Analizę cytowanych równań, oparto na wynikach własnych badań eksperymentalnych. Na podstawie przeprowadzonych prac, wskazano na równania najlepiej opisujące lepkość mieszaniny emulsyjnej.

EN

A literature survey of calculation methods dealing with viscosity of emulsion mixtures is given. An attempt of employing these methods in the description of viscosity of concentrated oil—water emulsion mixtures was made. The analysis of equations cited was based on the own experimental results. The best equations for calculation of viscosity of emulsion mixture were selected.

2

Thermodynamic analysis of the influence of potassium on the thermal behavior of kaolin raw material

100%

Hernández-Chávez M. , Vargas-Ramírez M. , Herrera-González A. M. , García-Serrano J. , Cruz-Ramírez A. , Romero-Serrano J. A. , Sánchez-Alvarado R. G.

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tom Vol. 57, iss. 1

39--52

EN

The mineralogy and thermal properties of two kaolin clay samples from Agua Blanca (Hidalgo-México) were determined by XRD, SEM-EDS, TGA-DSC techniques. Kaolin clay A contains a higher Al2O3 and lower impurities (K2O, TiO2, Fe2O3) amount than kaolin clay B, while the SiO2 amount is similar for both kaolin clays. A theoretical approach was carried out by a thermodynamic analysis considering the chemical composition of both kaolin clay samples with the FactSage 7.3 software. Stability phase diagrams were obtained to different K2O content from 0.1 to 3 wt % and temperatures in the range from 600 to 1600°C based on the chemical composition of the kaolin clay samples. The main mineralogical compounds predicted are andalusite (Al2O3•SiO2), K-Potash feldspar (K2O•Al2O3•6SiO2), and the SiO2 polymorphs (quartz, tridymite, and cristobalite) with small amounts of ferric-pseudobrookite (Fe2O5Ti), and rutile (TiO2). As K2O content is increased, the amounts of mullite and tridymite decrease meanwhile the potash feldspar is increased at high temperatures. A liquid phase is formed at around 1350 and 1400°C for the kaolin clay samples A and B, respectively. The viscosity of the melt is increased for the evaluated K2O additions to 1400, 1500, and 1600°C.

3

Analysis of the modern oil viscosity changes during their operation in combustion engines

100%

Młynarczak A. , Sikora G.

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tom Vol. 21, No. 4

361--368

EN

During normal operation, oxidation products gradually foul lubricating oil and external contaminants like fuel, water, sulphur compounds and friction nodes wearing products. As a result, lubricating oil changes its properties, among other things viscosity. In normal service conditions of marine diesel engines lubricating oil viscosity increases due to vaporizing of lube oil light ends during operation in high-temperature areas and oxidation process. Quantity of organic particulates accumulated in lubricating oil increases as a result of oxidation process. Oxidation products have bigger than lubricating oil molecular weight. So as to prevent oxidation process-lubricating oils are provided with antioxidant additives. On the other hand mechanical breakdown of high molecular substances in diesel engine bearings and gas oil leakages cause lubricating oil viscosity drop. The test results presented in the paper show that the lubricating oil viscosity during its operation in the internal combustion engines decreases. The value of viscosity decrease depends mainly on the motor's technical condition, the amount of oil in lube oil system, mode of ignition and its operation. Viscosity tests were performed for the lubricating systems of different engines on a Haake III Mars rheometer at 90 􀃛C for variable shear rates. Additionally, in order to determine engine condition, the detail analysis of the tested oil chemical content has been made oil using Spectrol Q100 spectrometer. In the most cases, the research results indicate lubricating oils viscosity decrease and it is possible to determine the relationship between the dynamic viscosity changes and shear rates for the particular engines. In authors opinion the viscosity drop of the tested modern lubricating oils may be caused by better antioxidant additives, which effectively moderate or even prevent the oxidation process. Lubricating oils viscosity drop is dangerous phenomena due to the lowering of the bearings capacity force and possibility of boundary friction.

4

Badanie olejów silnikowych klas lepkości 10W, 15W, 20W

100%

Fall J. , Voelkel A.

Przemysł Chemiczny

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2002

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tom T. 81, nr 1

25-31

5

High Temperature Study of Industrial Slag from Further Modelling Point of View

100%

Ślęzak M. , Karbowniczek M. , Migas P. , Ślęzak W. , Ślęzak M. , Karbowniczek M. , Migas P. , Ślęzak W.

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nr 2

6

Effect of temperature and concentration on rheological properties of beetroot juice

100%

Kobus Z. , Nadulski R. , Guz T. , Kamińska I.

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tom nr 17(1)

67--76

EN

The rheological behaviour of beetroot juice as a function of soluble solid content (from 10oBx to 50oBx) at a wide range of temperatures (from 10oC to 60 oC) was studied. The measurements were made using rotational rheometer (Brookfield Engineering Laboratories: model LVDV-II+ PRO). The investigation showed that the beetroot juice was Newtonian in behaviour and the viscosity was changed from 0.77 mPa s to 28.4 mPa s. The Arrhenius-Guzman equation was used to calculate the values of flow activation energy. In order to evaluate the influence of soluble solid content two models were applied: the power law and exponential equation. A new equation was proposed to express the combined effect of temperature and concentration on beetroot juice viscosity.

7

Modyfikaty skrobii o dużej lepkości

100%

Rupiński S. , Brzozowski Z. K. , Skwara K. , Zatorski W.

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tom T. 82, nr 8-9

1157-1160

PL

Przedstawiono wyniki badań nowo opracowanych pochodnych skrobi o dużej lepkości, zawierających grupy karbamoiloetylowe. Badano reakcje fosforanu diskrobiowego z akryloamidem na drodze addycji. Wielkościami poddanymi badaniom były: zawartość wodorotlenku sodu, czas i temperatura reakcji. Scharakteryzowano podstawowe właściwości tych polimerów przy użyciu różnych technik instrumentalnych, takich jak analiza elementarna, FT-IR oraz badania lepkości. Stwierdzono, że otrzymane pochodne skrobi są dobrze rozpuszczalne w wodzie i tworzą 4–8-proc. żele.

EN

Di-starch phosphate, 5 g in 50 mL H2O at 30°C, alkalized with 0.75 g NaOH (in 20 mL H2O), was carbamoylethylated 6 h with 2.5 g acrylamide (in 20 mL H2O) at 45°C, degree of substitution, 0.207% (max). The mixture was neutralized at 25°C to pH 7 with aq. 10% HCl; the product was precipitated with 1000 mL MeOH and dried at 75–80°C. At NaOH > 0.80 g, the degree of substitution fell owing to hydrolysis of amide groups to -COOH, and NH3 was released. At shear rates of 5–10 s-1, the (25°C, aq. 5%) viscosities of the products modified 2.5 h and 6 h were resp. 24 and 16 Pa·s vs. the 8 Pa·s of the starting di-starch phosphate. Product structure was confirmed by elementary analysis and FTIR.

8

Denaturation and aggregation of lysozyme in water-ethanol solution

100%

Szymańska A. , Hornowski T. , Ślósarek G.

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2012

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tom 59

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nr 2

317-322

EN

We have applied rheological methods for the analysis of ethanol-lysozyme interaction during the process of denaturation and aggregation of the protein. At low concentration of ethanol a destruction of the hydration shell of lysozyme is observed. With the increase in the ethanol concentration a structural transformation takes place. It leads to the formation of a protein aggregate with an elongated structure. The rheological characteristics of lysozyme-water-ethanol solution changes from Newtonian to pseudoplastic.

9

On one simulation method of turbulent flows

100%

Pavlenko A. A. , Nadrygailo T. Z.

Journal of New Technologies in Environmental Science

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2019

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tom Vol. 3, nr 4

169--178

EN

The article deals with the method of turbulent flows modeling with the help of turbulence models, which have the form of algebraic expressions. In well-known numerical simulation systems such models were not used to simulate the flowing of viscous liquid. The proposed models of turbulence make it possible to simplify the software implementation of the equations describing the turbulent behavior of fluid flowing and increase the speed of computation. The developed system of the computer modelling using the specified models, has the simple and clear interface, takes a little space on a disk, is undemanding to system resources, can be supplemented with new problems at plug-in level. The obtained results of computer simulation of liquid flowing around solids of different shapes confirm the adequacy of the turbulence models used. It allows to apply them for modeling turbulent flows at the solution of practical problems.

10

Studies of densities, viscosities and ultrasonic speeds of binary mixtures containing isopropyl alcohol and ketones at different temperatures

100%

Srinivas S. S. J. , Tulasi Koteswari Bai B. , Babu Rao K. , Narendra K. , Sarath Babu M.

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tom Vol. 10, iss. 2

151-158

EN

The densities, viscosities and ultrasonic velocities of binary liquid mixtures of Isopropyl alcohol with acetophenone and methyl isobutyl ketone (MIBK) have been measured at temperatures 298.15 and 308.15 K over the entire range of mole fraction. From these data, acoustical parameters such as adiabatic compressibility (β), free volume (Vf) and free length (Lf) have been estimated using the standard relations. The results are interpreted in terms of molecular interactions present in the mixtures.

11

Solvent Isotope Effect on Viscosity of Polystyrene-Benzene Solutions

100%

Siporska A. , Szydłowski J.

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tom Vol. 77 / nr 8

1007-1017

EN

The concentration and temperature dependences of viscosity and density of solutions of nearly monodisperse polystyrene samples (Mw/Mn < 1.06) in benzene and deuterated benzene have been determined. The measurements were conducted with samples of different molecular weights (Mw ) ranging from 4_103 to 4_105 between 293-313 K. Isotope H/D substitution in benzene causes visible changes in viscosity and density of solutions, however, its influence on intrinsic viscosities and Huggins constants, derived from the concentration dependences of viscosity, is negligible. No isotope effects on the exponents in the power law relationships have been detected. The viscosities of the solutions have been also correlated with the densities. The apparent close-packed volumes are practically constant for all solutions and seem to be determined by the properties of the solvent. The deuterium substitution visibly affects the close-packed volumes - they decrease by approximately 13%, both in pure solvent and in solutions.

12

Modelowanie charakterystyki konstytutywnej materiału SMA z uwzględnieniem lepkości

100%

Grzesikiewicz W. , Zbiciak A.

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tom T. 5, nr 36

113-118

PL

Celem pracy jest prezentacja matematycznego opisu związków konstytutywnych materiału SMA z uwzględnieniem zjawiska lepkości. Istota matematycznego opisu relacji fizycznych sprowadza się do sformułowania równania różniczkowego pierwszego rzędu względem tensora określającego niesprężystą część odkształcenia. Wykorzystano odpowiednio skonstruowany schemat reologiczny materiału SMA. Otrzymane relacje konstytutywne zostały zaprogramowanie w ramach procedury VUMAT, komercyjnego systemu MES ABAQUS/Explicit.

EN

The objective of the paper is the formulation of constitutive equations of viscous SMA material model. The key problem of the method proposed herein is to derive the 1st order differential equation with respect to the tensor describing non-elastic part of the strain field. This equation may be obtained in explicit form starting from the variational inequalities defining non-elastic parts of rheological model. The constitutive relationships were coded within VUMAT subroutine of the commercial FEM software ABAQUS/Explicit.

13

The use of a new technique to immobilize yeast cells in alginate capsules

100%

Wójcik M. , Grubecki I. , Trawczyńska I.

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tom No. 9/10

77--82

EN

A new technique for the encapsulation of yeast cells by elimination of any thickening agent has been evaluated. The proposed procedure is based on the application of a concentrated suspension of cells which already has the sufficient viscosity to obtain spherical capsules with a semipermeable membrane. Measurements have been conducted which show that, for suspensions with yeast cell concentrations higher than 20% dry weight, apparent viscosity depends not only on the yeast concentration, but also on shear rate. The influence of sodium alginate and calcium chloride concentrations on membrane thickness has also been studied.

14

Densities, Viscosities and Speeds of Sound of Binary Mixtures of Stereoisomeric Decalins

100%

Siporska A. , Szydłowski L.

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tom Vol. 81, nr 4

599-605

EN

Densities, viscosities and speeds of sound for the binary mixture of cis- and transdecalins have been measured over the whole composition range at 293.15 K and 305.15 K. The limiting partial volumes, excess volumes, deviations in viscosity and isentropic compressibilitywere calculated. It appeared that the mixture of stereoisomeric decalins is characterized by a moderate excess volume and relatively small deviations in viscosity and isentropic compressibility. The results were fitted to the Redlich – Kister equation.

15

Effect of concentrated microwave field on the rheological properties of liquid whole egg

100%

Oziemblowski M. , Regiec P.

Acta Agrophysica

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2002

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tom 77

16

Direct measurements of reaction time for extractive processes

88%

Gotfryd L. , Becker K. , Pietek G. , Szołomicki Z. , Piwowonska J.

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tom Vol. 52, iss. 2

909--919

EN

Extraction times for selected metal cations (Mg2+, Al3+, Zn2+, Cd2+, Cu2+, Ni2+, Co2+, Mn2+, Fe2+ and Fe3+) have been measured using cation-exchanging extractants - Versatic 10 (neodecanoic acid), DEHPA (bis(2-ethylhexyl)phosphoric acid) and Cyanex 272 (bis(2,4,4-trimetylpentyl)phosphinic acid). Data was collected directly by measuring and recording pH of the two phase reaction mixture with maintaining continuity of the aqueous phase. Similarly, the stripping rate of selected cations (Mg2+, Al3+, Zn2+, Cu2+, Ni2+, Co2+) in a sulphuric acid solution was measured. Viscosities of organic phases, saturated with cations, were measured before their stripping. Additionally, the extraction dependence of Mg2+, Al3+, Fe2+ and Fe3+ on pH was measured using Versatic 10 at various concentrations (7.5, 15 and 30 %).

17

Modelling of Love-type waves in an elastic layer sandwiched between viscous liquid half space and size dependent couple stress substrate

88%

Sharma V. , Kumar S.

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tom Vol. 57 nr 4

1009--1019

EN

Dispersion curves employed for designing Love wave based liquid sensing devices may provide more accurate information if due consideration is given to parameters describing microstructural behavior of the substrate. The present study involves mathematical modelling of Love waves propagating in a hybrid structure consisting of an elastic layer in the middle overlying a size dependent substrate, loaded with a viscous liquid (Newtonian) half space. Numerical computations are carried out to graphically demonstrate the effects of various parameters: characteristic length of the substrate, thickness of the elastic layer, viscosity and density of the overlying viscous liquid (Newtonian) on dispersion characteristics.

18

Ultrasonic speed, density, viscosity and associated acoustical parameters of chloroform solutions of symmetric double Schiff bases at 308.15K

88%

Gangan B. J. , Parsania P. H.

International Letters of Chemistry, Physics and Astronomy

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2015

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tom Vol. 45

16--23

EN

The density, viscosity and ultrasonic speed (2MHz) of chloroform and symmetric double Schiff bases have been investigated at 308.15K. Various acoustical parameters such as specific acoustical impedance(Z), adiabatic compressibility(Кa), Rao’s molarsound function(Rm), Vander Waals constant(b), internal pressure(π), free volume(Vf), intermolecular free path length(Lf), classical absorption coefficient(α/f2)Cl) and viscous relaxation time(τ) were determined using ultrasonic speed(U), viscosity(ƞ) and density(ƿ) data of Schiff bases solutions and correlated with concentration. Increasing linear or nonlinear trends of ( Z, Rm, b, τ and (α/f2)Cl) and decreasing trend of Кa, Lf, π and Vf with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions and solvophilic nature of the Schiff bases, which is further supported by the positive values of solvation number. The nature and position of substituent also affected the strength of molecular interactions.

19

Effervescent atomization of glycerol aqueous solutions

88%

Broniarz-Press L. , Ochowiak M. , Włodarczyk S. , Markuszewska M.

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tom nr 125

29--38

EN

Paper presents the rheological characteristics of glycerol aqueous solutions and spray structures, droplets diameters, drop size histograms for effervescent atomizers. The study shows a nonlinear relation between the Sauter mean diameter and the gas to liquid mass flow ratio. By increasing the concentration of glycerol the solution viscosity tends also to increase. The experimental results show that the size of droplets depends on the liquid viscosity. The diameter of droplets increases with increase of liquid viscosity. Drops size histograms based on the number of drops showed the increase in number of large and the decrease in small droplets with increase of concentration of glycerol. Additionally, the characteristic stages of atomized liquid have been presented: the jet with built-in bubbles (slug flow), satellite bubbles and connected bubbles.

20

The exergetic analysis for predicting of energy efficiency of the hydraulic drive systems

88%

Yakhno O. , Gubarev A. , Ganpantsurova O. , Murashhenko A.

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nr 5