When moving objects with a precision grip, fingertip forces normal to the object surface (grip force) change in parallel with forces tangential to the object (load force). We investigated whether voluntary wrist actions can affect grip force independent of load force, because the extrinsic finger muscles cross the wrist. Grip force increased with wrist angular speed during wrist motion in the h...

This study evaluated the mechanical performance of teardrop-shaped loops and teardrop-shaped loops with helix used in orthodontic space closure. Sixty retraction loops made with 0.019" x 0.025" stainless steel (SS) and beta-titanium (BT) wires were used. They were attached to a testing machine to measure the magnitudes of the sagittal force and the load-deflection ratio necessary for 1 mm, 2 mm...

introduction: the resistance to fracture of endodontically treated teeth restored with esthetic post systems has not been extensively researched. this in vitro study compared the fracture patterns of endodontically treated teeth with esthetic post systems with different analysis methods. materials and methods: a total of 26 recently extracted human maxillary central incisors were decoronated an...

introduction: many studies have been performed to evaluate the stress distribution around endodontic posts; those which compared posts composed of different materials are rare. the aim of this study was to compare stresses induced in dentin by three structurally different posts using photoelasticity method. materials and methods: nine blocks of psm-5 photoelastic material with 45×45×10 mm dimen...

The aim of this study was to determine how an additional load influences the force-vs-time relationship of the countermovement vertical jump (CMVJ). The participants that took part in the experiment were 18 male university students who played sport recreationally, including regular games of volleyball. They were asked to perform a CMVJ without involving the arms under four conditions: without a...

soil compaction can occur as a result of a number of factors. one of the most important factors is soil response to pressures imposed by wheels and soil engaging tools. this research investigated the effect of tyre load and inflation pressure on soil compaction-related factors. these factors include rut width, rut depth, cone index and horizontal force in different layers of soil profile. in th...

it is proposed to use a single base platform in the persian gulf considering its low depth and more appropriate environmental conditions in comparison to north sea and mexico gulf where this kind of platform is very popular. the pile of platform is responsible for transmission of environmental loads resulted from waves, currents, wind and dead loads to foundation of platform. using sacs 5.3 sof...

This paper explores grasping in robot-aided upper extremity rehabilitation, with a special focus on reaching and grasping exercises and the coordination between load force and grasp force. Six healthy subjects and two hemiparetic subjects performed \pick and place"movements with a haptic robot and virtual environment. These movements were segmented into three phases: grasping, transport and rel...

Assessing the behavior of composite structures which are subjected to impact loads is one of the important subjects in the field of mechanical sciences. Using thin-walled tubes which collapsed and absorbed the impact energy is a well-known method to prevent damages to the other parts of the structures. In this paper, deformations, crushing length, peak load, mean force and energy absorption cap...

The author has proposed a method, the Levitation Mass Method (LMM). In the LMM, the inertial force of a mass levitated using a pneumatic linear bearing is used as the reference force applied to the objects under test, such as force sensors, materials or structures. The inertial force of the levitated mass is measured using an optical interferometer. The author has modified it as calibration met...