scholarly journals Behavior of Friction in Pneumatic Cylinders with Different Relative Humidity

2020 ◽  
Vol 42 (3) ◽  
pp. 400-406
Author(s):  
V.-H. Pham ◽  
T.-D. Nguyen ◽  
T.-A. Bui
Author(s):  
Thuy Nguyen ◽  
Van Hung Pham

The pneumatic cylinder is influenced by many various factors at work, including the climate environment. The climatic environment consists of two characteristic factors as temperature (T) and relative humidity (RH), which change according to seasons and different geographical regions. Therefore, changing the climate characteristic factors will affect the friction characteristic of pneumatic cylinders when operating at different speeds. This article presents empirical research on the simultaneous effects of temperature and relative humidity of the environment with the humid tropical climate in Vietnam on the pneumatic cylinder's friction properties. According to experimental planning, the studies were conducted on industrial pneumatic cylinders with two input factors: the temperature of 150C, 320C and 490C and relative humidity of 51%, 75% and 99%, with velocities of 30, 50 and 100 mm/s. The results show that the static friction force and dynamic friction decrease when T, RH increases, and the influence of air relative humidity on friction force is more significant than temperature. The experiment also gives an empirical regression equation on the relationship of friction in the pneumatic cylinder, depending on the two factors of temperature and relative humidity of the humid tropical climate in Vietnam with velocities of 30, 50 and 100 mm/s.


2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040139
Author(s):  
Thuy-Duong Nguyen ◽  
Van-Hung Pham

The movement of a piston rod in a pneumatic cylinder is directly affected by the air humidity in the atmosphere, especially in the case of piston rods without any means of protection or grease on their surfaces. In a pneumatic cylinder system, the friction between the piston rod and the rod seal is sliding friction, and it has a significant value that varies with the variation in the moisture on the piston rod’s surface. In this paper, an investigation of the friction characteristics of piston rods and rod seals in a pneumatic cylinder was carried out with different humidity and velocity values to understand the effect of lubricants on the moving parts of pneumatic systems in humid environments, where the friction characteristics of the displacements corresponding to the static and dynamic friction forces were displayed on a measuring device. The research results showed that the static friction forces tended to decrease by [Formula: see text] and that the dynamic friction forces tended to decrease by [Formula: see text] when the relative humidity increased from 51% to 99% at different velocities between 5 and 100 mm/s.


2018 ◽  
Vol 24 (1) ◽  
Author(s):  
LAKSHMI CHOUDHARY ◽  
PRABHAWATI PRABHAWATI

Prevalence of soil transmitted helminthes infections in apparently healthy school going children and other 528 people of different districts of Koshi regions of North Bihar were evaluated. Over all incidences of STHs infection was 39.39% during study. High incidence of STH was seen in the rainy season i.e., in the month of July and August, September, significantly higher (P<0.05) .The incidence of Ascaris lumbricoides was highest in the month of August (18.64%). The month of September was 15.25% followed by that of July (14.4%) and October with 10.16%. Also the incidence of hookworm registered the highest incidence in the month of June (19.27%) and lowest in the month of December (4.82%) during the study period. However prevalence of Trichuris trichiura was negligible and it was almost nil in the most of the months but was highest in month of September with 28.57% and lowest in October with 14.00% The climatic factors are responsible for soil transmitted helminthes which are temperature, rainfall and relative humidity. Ascariasis, Trichuriasis and Ancyclostomiasis (Hookworm infection) are found to be endemic in this region.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
MASROOR ALI KHAN ◽  
KHALID AL GHAMDI ◽  
JAZEM A. MEHYOUB ◽  
RAKHSHAN KHAN

The focus of this study is to find the relationship between El Nino and dengue fever cases in the study area.Mosquito density was recorded with the help of light traps and through aspirators collection. Climate data were obtained from National Meteorology and Environment centre. (Year wise El Nino and La Nina data are according to NOAA & Golden Gate Weather Services). Statistical methods were used to establish the correlation coefficient between different factors. A high significant relationship was observed between Relative Humidity and Dengue fever cases, but Aedes abundance had no significant relationship with either Relative humidity and Temperature. Our conclusion is that the El Nino does not affect the dengue transmission and Aedes mosquito abundance in this region, which is supported by earlier works.


2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 417-422 ◽  
Author(s):  
W. Oueslati ◽  
M. S. Karmous ◽  
H. Ben Rhaiem ◽  
B. Lanson ◽  
A. Ben Haj Amara

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