The Relation between Low-Temperature Rheology of Lubricating Mineral Oils and Gelatin Index

2008 ◽  
pp. 133-133-19
Author(s):  
RM Webber ◽  
HF George ◽  
MJ Covitch
Keyword(s):  
Low Temperature ◽  
Mineral Oils

Fluid Convection Models for Low-Temperature Grinding and Effect of Fluid Warming

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Lei Zhang ◽  
W. Brian Rowe
Keyword(s):  
Low Temperature ◽  
Convection Heat Transfer ◽  
Wheel Speed ◽  
Convection Heat Transfer Coefficient ◽  
Mineral Oils ◽  
Basic Assumptions ◽  
Fluid Convection ◽  
Heat Dispersion ◽  
Fluid Cooling ◽  
Experimental Values

Abstract The paper considers fluid convection in low-temperature grinding. Fluid cooling often predominates over all other forms of heat dispersion in the grinding zone particularly in low-temperature grinding. Experimental values of convection heat transfer coefficient (CHTC) up to and in excess of 200,000 W/m2K have been found by various researchers both for water-based emulsions and in one case for mineral oils employed in high wheel-speed grinding. Several convection models have been developed in recent years for the prediction of CHTCs in low-temperature grinding. This paper reviews advances in convection modeling and reconsiders the basic assumptions implied. A proposal is made for improved estimation for highly churned flow assuming a degree of fluid warming. Predicted coefficients are compared with measured values.

The influence of ethylene/α-olefin copolymers used as additives on the viscosity and low-temperature properties of mineral oils

Polimery ◽  
2000 ◽  
Vol 45 (05) ◽  
pp. 366-367
Author(s):  
NIKOLAI A. OSTROVSKY ◽  
SOFI T. BASHKATOVA ◽  
INESSA A. GRITSKOVA ◽  
EDWARD J. GRZYWA
Keyword(s):  
Low Temperature ◽  
Mineral Oils

Low-Temperature Ketone Dewaxing of Mineral Oils by Direct Cooking

1977 ◽  
Vol 16 (1) ◽  
pp. 120-124 ◽  
Author(s):  
C. Passut ◽  
P. Barton ◽  
E. Klaus ◽  
E. Tewksbury
Keyword(s):  
Low Temperature ◽  
Mineral Oils

An Experimental Study of Grease in Elastohydrodynamic Lubrication

1972 ◽  
Vol 94 (1) ◽  
pp. 27-34 ◽  
Author(s):  
S. Y. Poon
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Low Temperature ◽  
Elastohydrodynamic Lubrication ◽  
Time Dependent ◽  
Base Oil ◽  
Mineral Oils ◽  
Lubricating Film ◽  
Dependent Behavior ◽  
Inlet Zone

The formation of a lubricating film by grease in conditions pertinent to elastohydrodynamic lubrication is studied in a disk machine, and the thickness measured by means of a magnetic reluctance technique. The greases examined are three lithium hydroxystearate greases, of different soap structures and soap contents, a low temperature sodium-based grease, and a high temperature clay-based grease, all in mineral oils. The film thickness of greases in EHL differs from that of pure mineral oils in one important aspect: with one charge of the lubricant the thickness decreases continuously with time. The time-dependent behavior of greases is examined in relation to the thickener structure, viscosity of the base oil, and the conditions of the inlet zone.

scholarly journals Low-Temperature Rheology and Thermoanalytical Investigation of Lubricating Oils: Comparison of Phase Transition, Viscosity, and Pour Point

Lubricants ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 99
Author(s):  
Andreas Conrad ◽  
Annika Hodapp ◽  
Bernhard Hochstein ◽  
Norbert Willenbacher ◽  
Karl-Heinz Jacob
Keyword(s):  
Low Temperature ◽  
Crystallization Temperature ◽  
Pour Point ◽  
Flow Behavior ◽  
Petroleum Products ◽  
Lubricating Oils ◽  
Mineral Oils ◽  
Cooling Conditions ◽  
Viscosity Increase

According to the ASTM D97, the pour point is the temperature below which petroleum products cease to flow. To evaluate the relevance of pour point measurements for synthetic lubricating oils, we investigated the crystallization, melting temperature and low-temperature flow behavior of one mineral and five synthetic lubricating oils. The classification of three groups emerged from this process. The formation of paraffin crystals in mineral oils (I) below the crystallization temperature causes shear-thinning behavior and a yield point. The crystallization temperature determined in the thermal analysis and rheology correlates well with the pour point. Synthetic lubricating oils, which solidify glass-like (II), exhibit a steady viscosity increase with falling temperature. The temperature at which viscosity reaches 1000 Pas corresponds well to the pour point. Synthetic oils, especially esters, with complex crystallization behavior (III), exhibit supercooling depending on the shear rate and cooling conditions. For these lubricating oils, the pour point provides no information for low-temperature applicability.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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