Understanding the friction mechanisms between the human finger and flat contacting surfaces in moist conditions

Human hands sweat in different circumstances and the presence of sweat can alter the friction between the hand and contacting surface. It is, therefore, important to understand how hand moisture varies between people, during different activities and the effect of this on friction. In this study, a survey of fingertip moisture was done. Friction tests were then carried out to investigate the effect of moisture. Moisture was added to the surface of the finger, the finger was soaked in water, and water was added to the counter-surface; the friction of the contact was then measured. It was found that the friction increased, up until a certain level of moisture and then decreased. The increase in friction has previously been explained by viscous shearing, water absorption and capillary adhesion. The results from the experiments enabled the mechanisms to be investigated analytically. This study found that water absorption is the principle mechanism responsible for the increase in friction, followed by capillary adhesion, although it was not conclusively proved that this contributes significantly. Both these mechanisms increase friction by increasing the area of contact and therefore adhesion. Viscous shearing in the liquid bridges has negligible effect. There are, however, many limitations in the modelling that need further exploration

North of the Nullarbor Plain

For a few hardy dingo-trappers—experienced bushmen able and willing to endure the rigours pf a nomadic existence in a waterless country - the area to the north of the Nullabor Plains has long been a favoured watering ground. In the 1949-1950 season bounties were paid on about 3,000 dingo scalps from this area

Dingo destruction—destroying wild dog pups

Quite apart from the heavy financial losses caused in the sheep industry by the depredations of wild dogs (we use the term to cover both the true dingoes and various breeds of domesticated dogs running wild), the ghastly suffering which they cause should make every sheep-owner anxious to destroy these canine scourges wherever an opportunity offers. Wild dogs on killing sprees will maim and kill far more sheep than they can eat, but they cause the greatest suffering when teaching pups to kill. At such times, the adult dogs will disable sheep and leave them till the pups are brought up to inflict further suffering on the helpless victims. This process will be repeated again and again until the pups are able to make their own kills

Wildlife hazards from 1080 baiting

ONE-SHOT oat baiting with sodium fluoroacetate (1080) is a relatively safe method of trail baiting rabbits. The hazard to wildlife is small and every effort is made to further reduce the hazard by selective application of the poison

Wild dog investigations

Following the information gained during the expedition to the north of the Nullabor plains in 1951, which indicated that dogs were moving along well defined leads on to the Plains from the direction of the Warburton Ranges, the Agriculture Protection Board authorised a further expedition by the Vermin Control Branch to endeavor to trace the origin of the migrations. Large sandhills had prevented the Nullabor Plains expedition from following the leads as far north as planned

Rabbit control with 1080

The lower South-West areas have for some time past been regarded as perhaps the most difficult areas in Western Australia from the point of view of rabbit control. The farmer here has to contend with several factors, peculiar to this area, which make his work more difficult. Such obstacles as bracken fern, falling timber, good burrowing soil and a long breeding season combined with small holdings, lack of rabbit control experience, partial use of the cleared areas (tobacco and potato growers) and a low income potential, have rendered the task of rabbit control exceedingly difficult for the average farmer, especially in the Manjimup-Pemberton areas