Several transitions in the friction coefficient with increasing load are found on Au(111) in sulfuric acid electrolyte containing Cu ions when a monolayer (or submonolayer) of Cu is adsorbed. At the corresponding normal loads, a transition to double or multiple slips in stick-slip friction is observed. The stick length in this case corresponds to multiples of the lattice distance of the adsorbe...

For individuals with upper-extremity motor disabilities , the head-stick is a simple and intuitive means of performing manipulations because it provides direct proprioceptive information to the user. Through practice and use of inherent proprioceptive cues, users may become quite adept at using the head-stick for a number of diierent tasks. The traditional head-stick is limited, however, to the...

The theory of stick-slip is developed, based on the concept of a static and dynamic coefficient of friction. The dynamic coefficient is assumed to be independent of displacement and to depend wholly on normal stress across the surface. It is also assumed to be velocity-independent. The theory predicts that the stress drop during stick-slip is independent of machine stiffness. The displacement d...

The fluctuations in the vertical displacement angle of a stick balanced at the fingertip exhibit on-off intermitency. However, even a skilled balancer cannot indefinitely maintain a stick balanced at their fingertip. The survival function for stick balancing, P (tesc > t), is shown to have the form of a Weibul function, exp(−λt)β , where λ is a constant and β > 1. The measured survival function...

Even the most regular stick-slip frictional sliding is always stochastic, with irregularity in both the intervals between slip events and the sizes of the associated stress drops. Applying small-amplitude oscillations to the shear force, we show, experimentally and theoretically, that the stick-slip periods synchronize. We further show that this phase locking is related to the inhibition of slo...

S ince its introduction three decades ago, self-monitoring of blood glucose (SMBG) using finger-stick blood samples, test strips, and portable meters has aided diabetes management, principally by enabling patients— particularly those treated with insulin—to become full partners along with health professionals in striving for excellent glycemic control. Over time the use of glucose meters has be...

The ability to aid the visually impaired is a field that has the potential to advance itself with the improvement of technology. Many of these products that assist those in need can cost up to $650, which is an expense that not everybody in need can afford. This means that the technology doesn't get into the hands of all those who need the devices. The sonar walking stick designed in this repor...