A 3-D Simulation of the Upper Extremity and Trunk Movements during Wheelchair Propulsion
M. H. Moeinzadeh,* M. Haghpanahi,* M. R. Mallakzadeh
University of Illinois; Iran University of Science and Technology

Many long-term wheelchair users suffer from chronic shoulder pain. This problem is significantly caused by the loads acting upon the upper extremity and trunk during the wheelchair propulsion. This project involves the mathematical development and determination of the upper extremity joint forces and moments during wheelchair propulsion. The upper extremity and the trunk are modeled by a 3-D four-bar link system representing trunk, arm, forearm, and hand and with 10 degrees of freedom. Included in the model also are the significant muscle forces. Knowing the hand-rim interface loads and geometric factors of the wheelchair, the optimal wheelchair/user match may be obtained.

Electromagnetic Stimulator for Speeding the Bone-healing Process
M. H. Moeinzadeh,* M. Zardoshti-Kermani,* M. Ahanian
University of Illinois, Amirkabir University of Technology

Bones in normal condition are electropositive. When one is broken, there are electronegative charges around the broken part which enhances the healing process. Although there are some invasive approaches to maintain this electronegativity, noninvasive electromagnetic stimulators are preferred. This project involves the development of a biomechanical model of the bone-healing process. The model is used to obtain the optimal design parameters, such as wave form, intensity, and geometric parameters, for the most efficient bone-healing process. Two new strategies, discontinuous stimulation and time-dependent stimulation, are considered. A laboratory prototype stimulator using optimal parameters to be designed and manufactured.

Ground Reaction Force Analysis of Changing Direction during Walking
M. H. Moeinzadeh,* D. Xu*
University of Illinois (Conducted in the Department of Kinesiology)

Walking is the basic means of locomotion for human beings. Various aspects of walking have been studied by a number of researchers; however, there is limited information on the unique characteristics of changing direction during walking. This study investigates the kinetic walking patterns and properties of the ground reaction forces (GRF) in changing direction. Thirty-three subjects are tested through a walking protocol representative of all of the complex movements of directional walking. Their GRF and body movements are recorded via a force plate and motion analysis systems, respectively. The insight gained in this study will be helpful in the clinical diagnosis of dysfunctional walking.

Rigidity of External Fracture Fixation Devices
G. J. Pijanowski* (Vet. Biosci.), M. H. Moeinzadeh*
University of Illinois

There is growing evidence that the local mechanical environment has an important influence on the process of fracture healing. The configuration of an external skeletal fixator frame is known to affect the stiffness of the frame, and thus, the local mechanical environment. The purpose of this work is to develop a computer model of the frame and provide the clinician with information about the mechanical environment of the healing fracture. This will allow the clinician to alter the configuration of the frame to optimize the healing.

Effectiveness of the Integration of Human Factors in the Design of Power Tools
M. G. Strauss*
Privately funded

Power tools are used daily by the professional and the handyman. They can be great time savers or products that can deliver lacerations, amputations, or death. Research has focused on the guards on saws and how the saws are used. Tests have shown that some saws have guards that will move out of the way if they are accidentally bumped by the user. A 5500 rpm blade is the next object to come in contact with the hand after the guard has moved. Considering human movements when designing power tools will increase their safety.