Light scattering was used to measure the time-dependent loss of air entrapped within a submerged microporous hydrophobic surface subjected to different environmental conditions. The loss of trapped air resulted in a measurable decrease in surface reflectivity and the kinetics of the process was determined in real time and compared to surface properties, such as porosity and morphology. The ligh...

This paper presents a comparative study among friction behavior of several double-acting pneumatic actuators available to industrial use. A brief review covering the manner that pneumatic actuator manufacturers and current literature approach friction force and its usual models also is presented. After depicting friction test methodology and test apparatus, the comparison work is carried out th...

We study numerically the spatial properties of relaxation clusters in a two dimensional sandpile automaton with dynamic rules depending stochastically on a parameter p, which models the eeects of static friction. In the limiting cases p = 1 and p = 0 the model reduces to the critical height model and critical slope model, respectively. At p = p c , a continuous phase transition occurs to the st...

|III Abstract Powder metallurgy (PM) is usually used in manufacturing parts with complex geometries, such as gears and structural parts. The main attractions of PM are the high rate of material utilization, environmental friendliness of production, economic advantages (especially for complex geometries), and possibility of obtaining lighter components. To find a wide range of applications and c...

This paper investigates how the losses in a Free Piston Energy Converter during start, stop and idling affects energy consumption and required power from the supply system. Simulation results indicate that the electrical machine efficiency is the most critical factor during start. Moreover, by choosing the correct amplitude of the starting force, energy consumption during start can be reduced. ...

Nanoscale sliding friction involving a polystyrene melt near its glass transition temperature Tg (373 K) exhibited dissipation phenomena that provide insight into the underlying molecular relaxation processes. A dissipative length scale that shows significant parallelism with the size of cooperatively rearranging regions (CRRs) could be experimentally deduced from friction-velocity isotherms, c...

The creep theory of multipulley belt drive systems is reexamined and the belt is modeled as an elastic extensible string. An exact solution of the nonlinear steady state equations of a string is obtained which includes, elastic extension, Coulomb friction, radial and tangential accelerations, and the power loss due to friction between the belt and the pulleys. Most importantly, the present solu...

Distinctly quantum friction effects of three types are surveyed: internal friction, measurement-induced friction, and quantum-fluctuation-induced friction. We demonstrate that external driving will lead to quantum internal friction, and critique the measurement-based interpretation of friction. We conclude that in general systems will experience internal and external quantum friction over and b...

The friction is detrimental to the normal work of the servo system, but the friction mechanism is very complicated. In this paper, Tustin friction model is used as the friction parameter identification, reflecting the phenomenon of friction in the system, and laying the foundation for the friction compensation. Tustin model is a nonlinear friction one, and the friction properties can be reflect...

This study proposes two fuzzy logic controllers (FLCs) for operating control force of piezoelectric friction dampers used for seismic protection of base-isolated buildings against various types of earthquake excitations. The first controller employs a hierarchic control strategy in which a higher-level supervisory controller operates a single sub-level FLC by modifying its input normalization f...