BACKGROUND Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS A cylindrical type traveling wave ultrasonic motor usin...

BACKGROUND For many long standing practices, the rationale for them is often lost as time passes. This is the situation with respect to the storage and handling of equimolar 50% nitrous oxide and 50% oxygen volume/volume (v/v) mixtures. METHODS A review was undertaken of existing literature to examine the developmental history of nitrous oxide and oxygen mixtures for anesthesia and analgesia ...

Combining several materials (“phases”) into a composite material permits creation of new materials with tunable overall response, e.g., elastic properties, which can be related to the elastic moduli, arrangement, and concentrations of the composite’s phases. A recent advance predicts use of one phase having correctly tuned non-positive-definite elastic moduli (i.e., negative stiffness) in a two...

in the present  paper electrical conductivity (ec) of colloidal gas aphron (cga) suspensions was measured for anionic and cationic surfactants (sodium dodecyl sulfate (sds) and tetradecyl trimethyl ammonium bromide (ttab)). experiments were made for different concentrations of sds (6, 8.1, 10 mm) and ttab (2, 3.51, 5 mm). cga drainage behavior was observed and measured using 1 liter measuring c...

in this paper, numerical simulation of frp composite cylinder tubes progressive crushing processes is conducted using ls-dyna. details on the numerical modeling strategy are given and discussed. it is found that triggers introduced in the numerical simulation can effectively model the bevel trigger at the end of the tubular specimens. it is also found that two-layer finite element model based o...

The Steady state creep behaviour of a functionally graded cylinder made of isotropic composite containing varying distribution of silicon carbide particles has been investigated by a mathematical model. The creep behaviour of the FGM is described by a Norton's Power law. The effect of varying distribution of SiCP particles of creep stresses and creep rates in the FGM cylinder has been anal...

Organic phase change material (PCM) with macro-encapsulation is attractive in energy storage applications as it has relatively low cost. This study focuses on using PET plastic pipes to encapsulate paraffin and using low-cost float stones to increase the thermal conductivity of PCM modules as they have a special structure of high porosity. Float stones were immersed in the liquid PCM and an ult...