NUMERICAL ANALYSIS OF THE INFLUENCE OF TEMPERATURE ON THE FRICTION RESISTANCE OF A METAL-POLYMER SLIDING PAIR

Tribologia ◽  
2020 ◽  
Vol 292 (4) ◽  
pp. 17-26
Author(s):  
Mariusz Opałka ◽  
Piotr Kowalewski ◽  
Anita Ptak
Keyword(s):  
Tribological Properties ◽  
Low Temperatures ◽  
Polymer Materials ◽  
The Finite Element Method ◽  
Sliding Bearings ◽  
Influence Of Temperature ◽  
Friction Resistance ◽  
Mechanical And Tribological Properties ◽  
Influence Of Temperature On ◽  
Polymer Bearing

The paper presents numerical calculations of polymer sliding bearings during their operation at low temperatures. Calculations of the frictional moment and the contact area were performed for bearing pans made of PA and PEEK. In the numerical model, the influence of temperature on the mechanical properties (modulus of longitudinal elasticity) and tribological properties (coefficient of friction) were taken into account. The diversified influence of the temperature and thickness of the polymer bearing pans was demonstrated with regards to elements made of different polymer materials. At low temperatures (up to T = -50°C), a different (depending on the used polymer) influence of mechanical and tribological properties on the resistance to motion was found. The ABAQUS calculation package and the finite element method (FEM) were used in the calculations.

Optical Transitions in Chalcogenide Glasses From the Point of View of a Barrier-Cluster Model

2008 ◽  
Vol 39-40 ◽  
pp. 253-256
Author(s):  
Ivan Baník
Keyword(s):  
Optical Absorption ◽  
Low Temperatures ◽  
Cluster Model ◽  
Chalcogenide Glasses ◽  
Temperature Shift ◽  
Point Of View ◽  
Optical Transitions ◽  
Influence Of Temperature ◽  
Exponential Tails ◽  
Influence Of Temperature On

A barrier-cluster model of chalcogenide glasses is employed to analyze optical transitions near the absorption edge. The influence of temperature on the optical absorption is studied. The model is used to explain the temperature shift of exponential tails of the optical absorption and the temperature dependence of the optical forbidden-band width at low temperatures.

The influence of temperature on the succession of redial and cercarial generations of Fasciola gigantica in a snail host

Parasitology ◽  
1964 ◽  
Vol 54 (1) ◽  
pp. 59-65 ◽  
Author(s):  
J. A. Dinnik ◽  
N. N. Diknik
Keyword(s):  
Larval Development ◽  
Low Temperatures ◽  
First Generation ◽  
Cold Season ◽  
Snail Host ◽  
Fasciola Gigantica ◽  
Natural Conditions ◽  
Influence Of Temperature ◽  
Cercarial Production ◽  
Influence Of Temperature On

Experiments on the larval development of Fasciola gigantica carried out under natural conditions have shown that at temperatures of 16° C. or less the rediae did not produce cercariae. The first-generation rediae, developed from the sporocyst, and all the rediae of subsequent generations produced only daughter rediae and did not change over to the production of cercariae as long as the low temperatures of the cold season lasted.As soon as the cold season ended and the temperature of the water in the aquaria containing the infected snails rose to a mean maximum of 20° C. all the rediae switched from redial to cercarial production.

Influence of Temperature on Performance in Guinea Pigs

1957 ◽  
Vol 190 (3) ◽  
pp. 457-458 ◽  
Author(s):  
Charles G. Wilber
Keyword(s):  
Low Temperatures ◽  
Guinea Pigs ◽  
Peak Performance ◽  
Albino Rats ◽  
Small Animals ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Endocrine Factors ◽  
The Difference ◽  
Large Animals

Guinea pigs were forced to swim to total exhaustion in water at various temperatures. Small animals (400 gm) showed peak performance at about 40°C, large ones (1000 gm) at about 35°C. Large animals swam longer at low temperatures but shorter at high temperatures than did small ones. At 35°C all guinea pigs swam for an average of about 150 minutes. In general this species shows much less capacity for swimming than do albino rats. The difference may be related to diet or to endocrine factors.

scholarly journals THE INFLUENCE OF TEMPERATURE ON THE ACTION OF STRYCHNIN IN FROGS

1913 ◽  
Vol 18 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Thomas Stotesbury Githens
Keyword(s):  
Low Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Room Temperature ◽  
Drug Action ◽  
The State ◽  
Great Caution ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

In order to establish the influence of temperature upon the effect of varying doses of strychnin injected into frogs, the animals must be kept under observation for several days and at various definite degrees of temperature. Statements that the animal was kept "cold," "at room temperature," or "warm" are insufficient. With a certain dose tetanus may result constantly at 30° C. yet never appear at 21° C., and either of these temperatures might be described as warm, when compared to a room temperature of 15° C. Furthermore an animal may apparently fail to respond in the cold to an injection of certain doses of strychnin and yet be found in tetanic convulsions the next day. That an animal may have late, long lasting, or strong tetanus while kept at such a low temperature as 5° C. after an injection of a dose of strychnin smaller than 0.01 of a milligram per frog emphasizes the fact that great caution must be exercised in formulating laws as to the influence of temperature on drug action. The main results of this investigation may be summarized as follows: Doses of strychnin amounting to 0.0006 of a milligram per gram of frog will cause tetanus at all temperatures between 5° C. and 30° C., although at low temperatures the tetanus may appear late. A dose of 0.0003 of a milligram per gram of frog will frequently produce tetanus at 5° C. as well as at 30° or 27° C., but may nevertheless fail to produce any reaction at such an intermediary temperature as 21° C. Smaller doses, 0.0002 of a milligram per gram, will cause tetanus in the cold but not at high temperatures. It may be stated in general that in frogs kept at low temperatures the tetanic state sets in later, continues longer, and each tetanic attack is of longer duration, while in the interval between the attacks the state of tonus is higher and the animals are more irritable than when they are kept at higher temperatures.

scholarly journals Evaluation of Tribological Properties of Polymer Materials Used for Sliding Bearings in Agricultural Machinery

2017 ◽  
Vol 21 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Mariusz Walczak ◽  
Jacek Caban ◽  
Andrzej Marczuk
Keyword(s):  
Tribological Properties ◽  
Technological Development ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Agricultural Machinery ◽  
Sliding Bearings ◽  
Economic Criterion ◽  
Agricultural Engineering ◽  
Polymer Metal ◽  
Materials Used

Abstract The continuous technological development requires the use of modern materials also in agricultural engineering. Knowledge of the characteristics of tribological materials pairs cooperating with each other is useful for developing sliding nodes of agricultural machinery. Tribological properties of materials should be assessed for selection of technological materials beyond the economic criterion. The article presents analysis of the characteristics of tribological ball-on-disc wear of polymeric materials used as sliding elements for farm machines. Tribological tests were carried out under dry friction for a polymer-metal pair, and a wear rate and friction coefficient of the sample; the signs of wear were submitted to SEM observations.

Evaluation of the combined temperature and relative humidity preferences of the Colombian terrestrial salamander Bolitoglossa ramosi (Amphibia: Plethodontidae)

2018 ◽  
Vol 96 (11) ◽  
pp. 1230-1235 ◽  
Author(s):  
C.A. Galindo ◽  
E.X. Cruz ◽  
M.H. Bernal
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Low Temperatures ◽  
Environmental Temperature ◽  
Critical Factors ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Thermal Preferences ◽  
Cutaneous Respiration ◽  
Field Location

Temperature and humidity are critical factors for terrestrial lungless salamanders, as their body temperatures are largely determined by the environmental temperature and require moisture to sustain cutaneous respiration. Herein, we evaluated the preference of Bolitoglossa ramosi Brame and Wake, 1972 between a high temperature and a high relative humidity (RH), the influence of temperature on RH preferences, and the influence of RH on the thermal preferences. This study was performed in a field location in the municipality of Líbano, Tolima, Colombia. There, on different nights, we collected 84 adult B. ramosi and carried out the preference experiments, using aluminum troughs with different thermal and RH gradients. We found that between high temperature and high RH, B. ramosi preferred high RH. However, B. ramosi selected high temperatures when the gradient had a high RH and low temperatures when the gradient had a low RH. These results show that B. ramosi is able to thermoregulate and hydroregulate. Nevertheless, hydroregulation seems to be more important than thermoregulation because B. ramosi always selected the high RH gradients, while their thermal selection relied on the hydric environment.

scholarly journals Microstructure and Tribological Properties of Self-Lubricating FeS Coating Prepared by Chemical Bath Deposition Coating Technique

2019 ◽  
Vol 9 (20) ◽  
pp. 4422 ◽  
Author(s):  
Jianjun Hu ◽  
Chuan He ◽  
Xian Yang ◽  
Hui Li ◽  
Hongbin Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Chemical Bath Deposition ◽  
Tribological Properties ◽  
Energy Dispersive Spectrometry ◽  
X Ray Diffraction ◽  
Influence Of Temperature ◽  
X Ray ◽  
Coating Technique ◽  
Influence Of Temperature On ◽  
Scanning Electron

The FeS solid lubricating coatings were prepared on the AISI 5140 steel by chemical bath deposition (CBD) coating technique at various temperatures from 30 to 90 °C. The influence of temperature on microstructure, microcracks, and tribological properties was characterized and studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometry (EDS). The results show that the coating mainly consists of FexSy (FeS, FeS2, and Fe1−xS), and has a chrysanthemum-shaped (CS) morphology composed of the FeS crystal petals. The CS particles nucleate at about 30 °C, rapidly grow and reach a peak thickness at about 50–70 °C, and finally disappear and are replaced by disordered thick petals at 90 °C. The wear resistance of the steel was improved obviously after introducing of FeS coatings, owing to that the coatings can provide better lubrication and improve the wear resistance.

scholarly journals ACOUSTIC EMISSION UNDER TEMPERATURE TESTS OF MATERIALS

Aviation ◽  
2005 ◽  
Vol 9 (4) ◽  
pp. 24-28 ◽  
Author(s):  
Vitalii Babak ◽  
Sergay Filonenko ◽  
Viktor Kalita
Keyword(s):  
Plastic Deformation ◽  
Acoustic Emission ◽  
High Temperatures ◽  
Low Temperatures ◽  
Theoretical Research ◽  
Influence Of Temperature ◽  
Intermediate Area ◽  
Influence Of Temperature On

The theoretical research of the influence of temperature on the parameters of the alteration of acoustic emission signals from plastic deformation is considered. It is shown that increasing temperatures cause an increase in the amplitude of acoustic emission signals in an area of low temperatures and a decrease in an area of high temperatures. At the same time, there is an intermediate area of temperatures in which the amplitude of acoustic emission signals remains constant when temperature is increased. As shown in the article, this fact is connected with the alteration of the process of plastic deformation.

Sign in / Sign up

Export Citation Format

Share Document