The work presented here provides a mathematical model for solving the problem of lubrication (calculation of efficiency) of worm gear drives, including a description of the engagement geometry and comprehensive modeling of the worm gear drive lubrication process based on the physical characteristics of the lubricant and the applied materials of contact bodies. The established mathematical model is based on the thermo-elasto-hydrodynamic (TEHD) lubrication theory that has proven to be successful in the analysis of journal bearings. The solution of the problem on hand by analyzing the loss of power in gearing, i.e. by analyzing the efficiency ratio of the gear, is basically reduced to the problem of mathematical modeling of local friction coefficients in the oil film along the contact line of the gears. The applicability of TEHD lubrication and the developed computer program were verified by comparing numerical results with experimental values obtained on a test bench using a real worm gear.

In the article are presented the results of our research on chlamydophilosis in parrots, free-living and breeding pigeons, and intensive breeding chickens in Bosnia and Herzegovina. For detection of the antigen two immunoenzyme tests for the detection of antibodies against Chlamydophila psittaci and a complement fixation test by a Kolmer and indirect immunofluorescence method (BioMerieux, France) were used. From a total of 275 samples of cloacal swabs the presence of Chlamydophila psittaci antigen was detected by ELISA (DAKO Ltd., United Kingdom) in 34.9% birds: 45.5% in intensive breeding chickens, 12.1% in free-living pigeons and 8.0% in parrots. By the same method the presence of Chlamydophila psittaci antigen in breeding pigeons was not detected. Sixty cloacal swabs from intensive breeding chickens and pigeons were tested by immunoenzyme test (Unipath Limited, England) and the presence of the pathogen was found in 6.7% cases. Fifty-eight sera from free-living pigeons and intensive breeding chickens were tested for the presence of specific antibodies to Chlamydophila psittaci by indirect immunofluorescence method and were found in 42.1% examined sera of pigeons, and in 27.6% pigeons from the total number of examined birds. The presence of specific antibodies was not found in sera of intensive breeding chickens. Using a complement fixation test, antibodies were not detected in the examined sera in pigeons nor in intensive breeding chickens. The results of this study show that the presence of antigens and antibodies for Chlamydophila psittaci is obvious in tested sera samples, but the clinical disease was not found in any of the examined birds.