Richard Kyung

Biomechanical analysis of aortic valve

The purpose of this study was to investigate the physical effects of aortic valve stenosis on the human heart, as well as to link the progression of aortic valve stenosis to the homeostatic mechanisms and sensitivity of the heart. Mean systolic pressure gradient (in mmHg) values are used as input into the equation produced aortic valve areas. Higher pressure gradient values produced smaller aortic valve areas, and thus indicated that aortic valve stenosis area was inversely proportional to mean systolic pressure gradient value across the valve. With the conclusion of our findings, it was determined that aortic valve stenosis was responsible for initial aortic valve area decrease, but progression of aortic valve stenosis was compelled by the maladaptive and contradictory feedback mechanisms of the heart responsible for maintaining blood flow stability.

Stability analysis of tibial bone

By using the bone remodeling technique, the physiological solutions and stress distributions of the tibial bone and impact conditions causing the fracture in the bone have been found using computational simulations. Also, assuming that the energy carried by the moving objects mass before collision is totally transferred to the tibial bone during impact, this paper presented the total energy that causes the tibia to fracture. The results can be compared to the empirical results found by other scientists, and the data could help improve the surgical treatment of knee arthroplasty.

Influence of Eccentric Loading and Size of Implant Fixture on the Stress Distribution in the Implant

The relation between eccentricity loading and implant diameter and the reaction force versus implant diameter were analyzed. Under distributed loading, the stress was larger at the abutment/fixture interface and in the crestal bone, compared to the stress pattern under vertical loading. The amount of stress at the superstructure was similar regardless of the length, diameter, and platform shape of a fixture. Finite element models were constructed in mandible having single screw-type implant fixture connected to the premolar superstructure; this was done in order to evaluate how the length, diameter, and platform shape of a screw-type fixture influence the stress in the supporting tissue around fixtures.

Pressure analysis of the blood flow in the arteriole

Poiseuilles law relates the flow rate with the pressure, viscosity, vessel radius and length. For the purposes of this exhibit, we will assume that the vessel in consideration is a small artery or an arteriole. Specifically, the complete circulatory system has a mean pressure drop of approximately 98 mmHg and the arterioles comprise 50% of this decrease. Using the mean velocity, blood pressure gradient can be expressed in terms of the velocity of the arteriole flow. Based on Poiseuilles law, this paper presented how the blood flow depends on the pressure and diameter of arteriole.