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Engineering senior section.

Card, Nathan *, V. Varma. "Self Consolidating Concrete--A Comparison With Conventional Concrete." Self Consolidating Concrete (SCC), also known as Self Compacting Concrete, was first proposed in 1986 by Professor Hajime Okamura of Kochi University of Technology, Japan. SCC is still an emerging technology, only in its infancy. SCC consolidates under its own weight. Unlike conventional concrete that needs vibration to fill all the voids and surround the rebar in the forms, SCC uses little or no vibration. This paper examines many of the aspects of SCC including comparisons of strength and durability with conventional concrete. Also are compared, shrinkage, resistance to cycles of freezing and thawing, and cost. The ability of concrete plants to use locally available material to make SCC is also evaluated in the paper, in addition to discussion on some of the admixtures used in making self consolidating concrete.

Rai, M. and T. Guess. Department of Mechanical Engineering, University of Missouri--Kansas City. Development Of A Three Dimensional Computational Dynamic Model Of The Knee Joint For A Detailed Understanding Of Its Function. The knee is one of the most complex joints in the human body and experiences a significant amount of stress and loading during motion. Two joints exist in the Knee. One is the patellofemoral joint between the patella and femur and the other is the tibiofemoral joint between the tibia and femur. We are developing a rigid body model with deformable contacts that will incorporate the inertial properties of the tibia, femur and patella. The model is being developed in MSC. ADAMS and includes geometries from MRI images of the tibia, femur and patella. Appropriate insertion sites for muscles have been determined and will be used to define the line of action of muscle forces. In addition, major ligaments crossing the knee will be modeled as non-linear springs. The material properties of cartilage covering the articulating surfaces of the knee will be formulated into contact parameters for the deformable contacts at the patello-femoral and tibiofemoral joints. The three dimensional model will help in the analysis of muscle activation patterns and the motion of the patella in a step up task. It will also aid in the understanding of the magnitude and direction of forces that will act on the femur, tibia, and patella. This analysis will be used for the study of dynamic stress development on the patella and to find ways of reducing it.

Rayaprolu, J. and T. Guess. Department of Mechanical Engineering, University of Missouri --Kansas City. Control Of Muscle Activation And Force To Minimize Stresses In The Patello-Femoral Joint. The Patello-femoral joint is a complex joint that experiences high forces during everyday activities. This joint is comprised primarily of the patella, femur, tibia, quadriceps muscles, and the patellar tendon. Bone geometries provide static constraints to patellar motion and muscle forces provide dynamic constraints. It is generally believed that poor tracking of the patella is a prevailing cause in the onset of patello-femoral pain. In this project we are trying to minimize the patellar stress while performing a step up task using a 3-Dimensional dynamic knee model focusing on the dynamic constraints. The model is being constructed as a rigid body model that includes muscle forces, ligament constraints, and anatomical bone geometries with deformable contacts. Clinical studies have shown that the muscle activation pattern of the quadriceps has a relation to patello-femoral joint pain. This pattern will affect muscle forces which could in turn control patellar tracking; our study will prove or disprove this hypothesis by controlling the muscle activation to minimize stress and analyze the results. To this end we will be developing a control algorithm with a defined "Joint Stress" as an error signal. The difference between maximum stress and the average stress over a finite area would give the stress which is a variable. This variable stress is fed as an error signal to minimize the joint stress. Our study will help give better insight into the dynamics of the knee joint and could contribute to the prevention and treatment of patello-femoral pain.

Virendra K. Varma

Missouri Western State College
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Title Annotation:Collegiate & Senior Divisions
Author:Varma, Virendra K.
Publication:Transactions of the Missouri Academy of Science
Geographic Code:1U4MO
Date:Jan 1, 2004
Previous Article:Conservation senior section.
Next Article:Geology & geophysics senior section.

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