Whether blood flow during cardiopulmonary resuscitation (CPR) results from intrathoracic pressure fluctuations or direct cardiac compression remains controversial. From modeling considerations, blood flow due to intrathoracic pressure fluctuations should be insensitive to compression rate over a wide range, but dependent on the applied force and compression duration. If direct compression of th...

In this article, curvature effects on elastic thermal buckling of double-walled carbon nanotubes under axially compressed force are investigated using cylindrical shell model. Also, the small scale effect is taken into account in the formulation. The dependence of the interlayer van der Waals (vdW) pressure on the change of the curvatures of the inner and outer tubes at that point is considered...

BACKGROUND Duty cycle is the portion of time spent in compression relative to total time of the compression-decompression cycle. Guidelines recommend a 50% duty cycle based largely on animal investigation. We undertook a descriptive evaluation of duty cycle in human resuscitation, and whether duty cycle correlates with other CPR measures. METHODS We calculated the duty cycle, compression dept...

Actual applications of the energy absorbers showed that actual loads are not applied in the form of pure axial compression, pure bending or pure torsion. In reality, an energy absorber component may be subjected to combined loading of compression, bending and torsion. A number of previous articles have investigated the behavior of energy absorbers under oblique loading. In such cases, the obliq...

In this paper, crashworthiness characteristics of conical steel tubes stiffened by annular rings and rigid polyurethane foam are investigated. For this purpose, wide circumferential rings are created from the outer surface of the conical tube at some determined areas along tube length. In fact, this method divides a long conical tube into several tubes of shorter length. When this structure is ...

some numerical and experimental investigations are made on the performance of five different hyperelastic constitutive models (second order polynomial, yeoh, arruda-boyce, ogden and marlow) in tension and compressionmodes. first, the results of the tensile and compression tests on a rubber sample were used to determine the parameters of the models by curve fitting methods. next, by using an alg...

BACKGROUND Cricoid pressure or to be more exact cricoid force (CF) can cause airway obstruction and subsequent difficulty with airway management during an emergency induction. METHODS We studied 30 children with an age range of 3 months to 15 yr who presented for routine bronchoscopy or other surgical procedures requiring tracheal intubation. We looked at the effect of CF on the calibre of th...

A single keycap on a standard alphanumeric computer keyboard was instrumented with a piezoelectric load cell and the fingertip motion was recorded with a high-speed video motion analysis system. Contact force histories between the fingertip and the keycap were recorded while four subjects typed a standard text for five minutes. Each keystroke force history is characterized by three distinct pha...

The topic of this article is the compression physics of different gum bases which can be used to prepare chewing gumtablets by direct compression. Three different gum bases, Pharmagum® C, M and S, were tested alone and in differentcombinations. The preparations were compressed with a Korsch EK0 eccentric tableting machine at compressionforces of 5, 7.5, 10, 12.5 and 15 kN. The c...

BACKGROUND Pelvic circumferential compression devices are designed to stabilize the pelvic ring and reduce the volume of the pelvis following trauma. It is uncertain whether pelvic circumferential compression devices can be safely applied for all types of pelvic fractures because the effects of the devices on the reduction of fracture fragments are unknown. The aim of this study was to compare ...