Abstracts / Journal of Biomechanics 44 (2011) ee1–e21 ee17

affected by the geometry of the artery. Shapes of the velocity historiesat most of the selected points are very similar to the shape of therelevant inlet velocity histories while it is very different for someselected points.

Study concludes that the input boundary conditions and slope/curvature discontinuities in the geometry affect the velocity, pressureand WSS distributions highly. The conclusion is supported by thedevelopment of secondary flow at inflexion regions and vortex atespecially the sinus area.

doi: 10.1016/j.jbiomech.2011.02.059

A comparison between non-Newtonian andNewtonian blood viscosity models

Hasret Turkeri, Senol Piskin, M. Serdar Celebi

Istanbul Technical University, Informatic Institute, Computational

Science and Engineering, Istanbul, Turkey

In this study the effects of some non-Newtonian viscosity andNewtonian viscosity models on the Wall Shear Stress and velocitydistributions in carotid artery are investigated. Three distinct non-Newtonian viscosity models named Carreua, Casson and General-ised Power Method and Newtonian model are employed in thesimulations. 3D Navier–Stokes equations is solved numerically onanatomically realistic geometry which is obtained from CT data. Atthe inlet of the numerical model experimental flow data which ismeasured at a real common carotid artery is imposed. The WSSand velocity distributions which are calculated using differentviscosity models are compared. Results show that the differencesbetween non-Newtonian models and Newtonian model areimportant at the regions having low velocity.

doi: 10.1016/j.jbiomech.2011.02.060

Production of a bio-compatible metallic implantvia electropolymetrization method by coating asynthetic hydrogel on a titanium alloy

Duygu Korsacilar, Aylin Albayrak, Ugur Malayoglu

Dokuz Eylul University, Metallurgy and Materials Engineering

Department, Tinaztepe, Izmir, Turkey

Recently, titanium implants are used to solve many differenthealth problems. Features of titanium, such as lightness,strength, high corrosion resistance and bio-compatibility haveincreased the usage of titanium in bio-materials. Titanium platestake an important role, especially in integrating bone fractures.Although titanium implants are essential materials for thispurpose, to minimize the risks during healing period, bio-activetitanium surfaces are desired.

The aim of this study is to coat titanium alloy (Ti–6Al–4V)which is used as an implant material with a synthetic bio-compatible hydrogel, poly(HEMA–GDMA), by electropolymer-ization method in order to develop the functionality and thebio-compatibility of the material.

In order to improve the adhesion of the coatings to the metalsurface, first titanium working electrodes, were encapsulated inbakelite as circular plates and polished flat to a 3 mm finish. Then,each electrode was cleaned in an ultrasonic bath using ethanolfor 10 min, rinsed with water and dried.

All potentiostatic coating experiments were carried out usinga potentiostat–galvanostat and an H-type glass cell. In the cell,(NH4)2S2O8 and H2SO4 were used as the initiators of the electro-polymerization where HEMA was the monomer and GDMA wasthe crosslinker. Na2SO4 was also added to increase the conduc-tivity of the solution as well as the thickness of the coatings.Titanium alloy (Ti6Al4V), reticulated vitreous carbon electrode(RVC) and saturated calomel electrode (SCE) were chosen asworking electrode, counter electrode, and reference electrode,respectively. The electrochemical cell was purged with nitrogenfor 30 min before any potential was applied. Then potential wasramped at 1 mV/s from 0 V (vs. SCE) to the desired potential andheld for 30 min. During the electropolymerization, nitrogenpurging was continued.

First optimum coating conditions were determined in termsof applied potential, initiators, monomer and cross-linkerconcentrations. Then the surface morphologies of the coatingswere examined by optical microscope and scanning electronmicroscope (SEM), the chemical characterizations were doneusing Fourier Transform Infrared Spectroscopy (FT-IR). Surfaceroughness and thickness of the coatings were obtained bythe surface profilometer device. As a result, white and opaquecoatings of poly(HEMA–GDMA) were produced uniformly onTi6Al4V cathodes via electropolymerization method. Hazy sur-faces of the coatings indicate the diffusion of light on reflectanceas a result of rough surface morphology. Na2SO4 addition isimportant as it increases the conductivity leading to thickercoatings.

doi: 10.1016/j.jbiomech.2011.02.061

Comparison of 3D and 2D models editing process inpre-osteotomy planning

_Ibrahim Mutlu a, Arif Ozkan a, Halil Atmaca a, Talip C- elik b,M. Yavuz Cirpici c, Yasin Kisioglu a

a Department of Mechanical Education, Kocaeli University, Umuttepe,

41380 Kocaeli, Turkeyb Department of Orthopaedics and Traumatology, Kocaeli University,

Umuttepe, 41380 Kocaeli, Turkeyc Department of Orthopaedics and Traumatology, Istinye State

Hospital, Istanbul, Turkey

Surgeons are generally applying the surgical corrections topatients having different anatomical deformities. Based onthese deformities, a suitable preoperative planning is reducingthe adverse effects during the operations and even postopera-tions. Preoperative planning is usually done using the 2DX-rays. In addition to this, some computerized 3D developedprograms use the CT and the MR images to create the 3D solidmodel of the orthopedical patients are used for preoperativeplanning. In this study, 2D picture image program, AdobePhotoshop, and computer aided 3D image process program,MIMICS, are used to model in 2D and correct the lowerextremity deformities of two patients. Based on these