the repetitious nature of propelling a wheelchair has been associated with the high incidence of injury among manual wheelchair users (mwus), mainly in the shoulder, elbow and wrist. recent literature has found a link between handrim biomechanics and risk of injury to the upper extremity. the valid measurement of three‑dimensional net joint forces and torques, however, can lead to a better unde...

Undergraduates observed configurations of point-lights undergoing wheel-generated motions and judged how wheel-like the movement of each stimulus appeared on a 7-point scale. Viewer judgments were predicted by a metric defining the variable parameters for the motion path of each configuration’s geometric center--the centroid. The effects on judgments of eye movement and the stimulus characteris...

A set P = H ∪ {w} of n + 1 points in the plane is called a wheel set if all points but w are extreme. We show that for the purpose of counting crossing-free geometric graphs on P , it suffices to know the so-called frequency vector of P . While there are roughly 2 distinct order types that correspond to wheel sets, the number of frequency vectors is only about 2n/2. We give simple formulas in t...

A thin-film balance employing either a Sheludko capillary or a Mysels-inspired porous-medium film holder provides a direct measurement of disjoining-pressure isotherms in free, liquid thin films. However, each film holder suffers its own distinct disadvantages spanning non-uniform and slow liquid exchange, a limited range of measurable disjoining pressures, an inability for reuse, and a require...

Although its absolute motion is the same, the path of a single moving point is often perceived differently when viewed alone than when viewed as a part of a dynamic configuration of many points. A point’s perceived motion path depends on the configuration in which it is embedded, with different configurations producing different perceived paths. The results of our research suggest that the perc...

The single wheel, gyroscopically stabilized robot Gyrover, is a dynamically stable but statically unstable, underactuated system. In this paper, based on the dynamic model of the robot, we investigate two classes of nonholonomic constraints associated with the system. Then, based on the backstepping technology, we propose a control law for balance control of Gyrover. Next, through transferring ...

tillage and press wheel weight play an important role in seedling emergence, crop establishment and growth. an optimal combination of tillage implements and suitable press wheel weights should increase grain yield. this study investigated the effect of tillage systems and press wheel weights on dry land wheat (triticum aestivum l.) seedling emergence and grain yields in izeh, khuzestan province...

We find an explicit expression of the Tutte polynomial of an $n$-fan. We also find a formula of the Tutte polynomial of an $n$-wheel in terms of the Tutte polynomial of $n$-fans. Finally, we give an alternative expression of the Tutte polynomial of an $n$-wheel and then prove the explicit formula for the Tutte polynomial of an $n$-wheel.

Articulated Wheeled Robotic (AWR) locomotion systems consist of chassis connected to a set of wheels through articulated linkages. Such articulated “leg-wheel systems” facilitate reconfigurability that has significant applications in many arenas, but also engender constraints that make the design, analysis and control difficult. We will study this class of systems in the context of design, anal...