scholarly journals The Investigation of Viscometric Properties of the Most Reputable Types of Viscosity Index Improvers in Different Lubricant Base Oils: API Groups I, II, and III

Lubricants ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Seyed Ali Khalafvandi ◽  
Muhammad Ali Pazokian ◽  
Ehsan Fathollahi
Keyword(s):  
Viscosity Index ◽  
Behavioral Differences ◽  
Base Oil ◽  
Polymer Molecules ◽  
Base Oils ◽  
Two Temperatures ◽  
Higher Temperature ◽  
Viscosity Index Improvers ◽  
Lower Temperature ◽  
Definition Of

Four commercial viscosity index improvers (VII) have been used to investigate the behavioral differences of these compounds in three types of universally applicable base oils. The used VIIs are structurally three types of co-polymer: ethylene-propylene, star isoprene, and two di-block styrene-isoprene. After dissolving of different amounts of VIIs in different base oils, the kinematic viscosities at two standard temperatures were determined and the intrinsic viscosities were calculated according to Huggins method, then the effects of changes in base oil and polymer type were investigated. Intrinsic viscosities as criteria for polymer molecules sizes were found to be higher at lower temperature than at higher temperature. Dependence of intrinsic viscosity on the polymer molecular weight was observed. In the previous works, one or two types of VIIs were studied in only one type of base oil and/or solvent, not different base oils. Furthermore, different ranges of temperatures and concentrations not necessarily applied ranges were selected, but in this work, common base oils and most commercial VIIs were used and the viscometric properties were compared at two temperatures. Viscosities at these temperatures are used for determining VI and definition of lubricant’s viscosity grades. VI improvement is the main cause of VII usage.

The study of the qualities of light and oil fractions of Azeri oil

2021 ◽  
Vol 02 ◽  
pp. 28-31
Author(s):  
G.S. Mukhtrova ◽  
◽  
Yu.A. Abdullayeva ◽  
R.Z. Hasanova ◽  
S.B. Logmanova ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Pour Point ◽  
Viscosity Index ◽  
Antioxidant Properties ◽  
Hydrocarbon Composition ◽  
Base Oil ◽  
Base Oils ◽  
Oil Fraction ◽  
Oil Fractions ◽  
Light Oil

The article provides research on the qualities of Azeri oil and its light and oil fractions. A characteristic feature of Azeri oil is its high content of light fractions. This oil is light, low-sulfur, and paraffinic. Azeri oil in terms of density, sulfur content, content of light (light) fractions corresponds to marketing grades of oils and is called Azeri Light. Along with light fractions, Azeri Light oil contains up to 30-32% of oil fractions boiling above 350°C. Studies of 50°C oil fractions 350-500°C showed that the viscosity of the fractions at 100°C is in the range of 2.5-10.2 mm2/s, the viscosity index is 72-79.3, and the pour point is 12-36°С, potential content of base oils - 25.73%, their hydrocarbon composition, %: n-paraffinic oils - 50.7; isoparaffinic + naphthenic - 10.67; aromatic - 8.94%. Using traditional methods of purification using a selective solvent, followed by dewaxing and hydrotreating, from 50°C oil fractions of Azeri oil, base oils with a viscosity of 4.2-9.0 mm2/s at 100°C and a viscosity index of 91.0 can be obtained - 95.8, pour point minus 15°С / minus 20°С. By cleaning a wide oil fraction of 350-500°C, it is possible to obtain a base oil with a viscosity at 100 C of 6.5 mm2/s (SAE 20), a viscosity index of 95, a pour point of minus 15°C, an oil yield (350-500°C) is 20.3% for distillate (12.4% for oil). In terms of saturated hydrocarbons content (≥90%, sulfur content less than 0.03%), viscosity index > 90, the oil has good antioxidant properties and can be assigned to API group II.

scholarly journals Temperature affects the repeatability of evolution in the microbial eukaryote Tetrahymena thermophila

2020 ◽  
Author(s):  
Jason A Tarkington ◽  
Rebecca Zufall
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Tetrahymena Thermophila ◽  
Correlated Responses ◽  
Trade Offs ◽  
Evolutionary Trajectories ◽  
Two Temperatures ◽  
Higher Temperature ◽  
Lower Temperature

AbstractEvolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliate Tetrahymena thermophila at low and high temperatures and followed changes in growth rate over 4,000 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes converged as evolution proceeded at both temperatures, but this convergence was quicker at the higher temperature. Likewise, we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found no evidence of trade-offs in fitness between temperatures, but did observe asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories.

Two Representations of the Moscow Art Theater Audience

2020 ◽  
Vol 17 (5) ◽  
pp. 462-476
Author(s):  
Alexander A. Ushkarev ◽  
Galina G. Gedovius ◽  
Tatyana V. Petrushina
Keyword(s):  
Online Community ◽  
Modern Art ◽  
Virtual Space ◽  
Demographic Parameters ◽  
Cultural Consumption ◽  
Cultural Activity ◽  
Behavioral Differences ◽  
Technological Revolution ◽  
Definition Of

The technological revolution of recent decades has already brought art to the broadest masses, and the unexpected intervention of the pandemic has significantly accelerated the process of migration of theatrical art to the virtual space, causing the corresponding dynamics of the audience. What is the theater audience in the era of digitalization and the spread of alternative forms of cultural consumption? How does the theater build its relationship with the audience today? In search of answers, we conducted a series of sociological surveys of the Chekhov Moscow Art Theater’s audience — both at the theater’s performances and in the online community of its fans. The purpose of this phase of the study was to answer the fundamental questions: do spectators surveyed in the theater and those surveyed online represent the same audience; what are their main differences; and what are the drivers of their spectator behavior? The article presents the main results of a comparative analysis of two images of the Moscow Art Theatre’s audience based on a number of content parameters by two types of surveys, as well as the results of a regression analysis of the theater attendance. The study resulted in definition of the qualitative and behavioral differences between the theater visitors and the viewers surveyed online, and identification of the factors of theater attendance for both of the represented audience groups. The study made it possible to clarify the role of age and other socio-demographic parameters in cultural activity, as well as the influence of preferred forms of cultural consumption (live contacts or online views) on one’s attitude to art, motivation and spectator behavior. The conclusions of the study, despite the uniqueness of the object, reflect the general patterns of the modern art audience’s dynamics.

scholarly journals Sprouting of Sorghum (Sorghum bicolor [L.] Moench): Effect of Drying Treatment on Protein and Starch Features

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 407 ◽  
Author(s):  
Mia Marchini ◽  
Alessandra Marti ◽  
Claudia Folli ◽  
Barbara Prandi ◽  
Tommaso Ganino ◽  
...  
Keyword(s):  
Food Production ◽  
Cost Effective ◽  
High Exposure ◽  
Effective Technology ◽  
Drying Treatment ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The One ◽  
Drying Conditions ◽  
Sorghum Bicolor L

The nutritional and physicochemical properties of sorghum proteins and starch make the use of this cereal for food production challenging. Sprouting is a cost-effective technology to improve the nutritional and functional profile of grains. Two drying treatments were used after sorghum sprouting to investigate whether the drying phase could improve the protein and starch functionalities. Results showed that the drying treatment at lower temperature/longer time (40 °C for 12 h) extended the enzymatic activity that started during sprouting compared to the one performed at higher temperature/shorter time (50 °C for 6 h). An increased protein hydrolysis and water- and oil-holding capacity were found in the flour obtained by the former treatment. Higher protein matrix hydrolysis caused high exposure of starch to enzymes, thus increasing its digestibility, while worsening the technological functionality. Overall, modulating drying conditions could represent a further way, in addition to sprouting, to improve sorghum flour’s nutritional profile.

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