Dwayne Arola

Bio: Dwayne Arola is an academic researcher from University of Washington. The author has contributed to research in topics: Dentin & Enamel paint. The author has an hindex of 47, co-authored 227 publications receiving 7190 citations. Previous affiliations of Dwayne Arola include University of Maryland, Baltimore & University of Maryland, Baltimore County.

Orthogonal cutting mechanisms of graphite/epoxy composite. Part II: multi-directional laminate

Abstract: An experimental study of orthogonal cutting mechanisms was conducted in the edge trimming of unidirectional Graphite/Epoxy composite with polycrystalline diamond tools. The effects of tool geometry and operating conditions were evaluated from an analysis of chip formation, cutting force and machined surface topography. All aspects of material removal were found to be primarily dependent on the fibre orientation. Discontinuous chip formation was noted throughout this study, regardless of trimming parameters. Chip dimensions and force measurements depicted a change in chip formation with fibre orientation, and the presence of three distinct mechanisms in the edge trimming of fiber reinforced composite material. A combination of cutting, shearing and fracture along the fibre/matrix interface was observed.

Applications of digital image correlation to biological tissues

Abstract: Optical methods are becoming commonplace in investiga- tions of the physical and mechanical behavior of biological tissues. Digital image correlation (DIC) is a versatile optical method that shows tremendous promise for applications involving biological tis- sues and biomaterials. We present the fundamentals of DIC with an emphasis on the application to biological materials. An approach for surface preparation is described that facilitates its application to hy- drated substrates. Three examples are presented that highlight the use of DIC for biomedical research. The first example describes the use of DIC to study the mechanical behavior of arterial tissues up to 40% elongation. The second example describes an evaluation of the me- chanical properties of bovine hoof horn in the dehydrated and fully hydrated states. Uniaxial tension experiments are performed to deter- mine the elastic modulus (E) and Poisson's ratio (n) of both the arterial and dermal tissues. Spatial variations in the mechanical properties are evident from the full-field characterization of both tissues. Finally, an application of DIC to study the evolution of loosening in cemented total hip replacements is described. The noncontact analysis enables measurement of the relative displacement between the bone/bone ce- ment and bone cement/prosthesis interfaces. Based on the elementary optical arrangement, the simple surface preparation, and the ability to acquire displacement/strain measurements over a large range of de- formation, DIC should serve as a valuable tool for biomedical re- search. Further developments will enable the use of DIC for in vivo

Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review

Abstract: As a practical and effective tool for quantitative in-plane deformation measurement of a planar object surface, two-dimensional digital image correlation (2D DIC) is now widely accepted and commonly used in the field of experimental mechanics. It directly provides full-field displacements to sub-pixel accuracy and full-field strains by comparing the digital images of a test object surface acquired before and after deformation. In this review, methodologies of the 2D DIC technique for displacement field measurement and strain field estimation are systematically reviewed and discussed. Detailed analyses of the measurement accuracy considering the influences of both experimental conditions and algorithm details are provided. Measures for achieving high accuracy deformation measurement using the 2D DIC technique are also recommended. Since microscale and nanoscale deformation measurement can easily be realized by combining the 2D DIC technique with high-spatial-resolution microscopes, the 2D DIC technique should find more applications in broad areas.

Ncorr: Open-Source 2D Digital Image Correlation Matlab Software

Abstract: Digital Image Correlation (DIC) is an important and widely used non-contact technique for measuring material deformation. Considerable progress has been made in recent decades in both developing new experimental DIC techniques and in enhancing the performance of the relevant computational algorithms. Despite this progress, there is a distinct lack of a freely available, high-quality, flexible DIC software. This paper documents a new DIC software package Ncorr that is meant to fill that crucial gap. Ncorr is an open-source subset-based 2D DIC package that amalgamates modern DIC algorithms proposed in the literature with additional enhancements. Several applications of Ncorr that both validate it and showcase its capabilities are discussed.

The initial stages of template-controlled CaCO3 formation revealed by Cryo-TEM

Abstract: Biogenic calcium carbonate forms the inorganic component of seashells, otoliths, and many marine skeletons, and its formation is directed by an ordered template of macromolecules. Classical nucleation theory considers crystal formation to occur from a critical nucleus formed by the assembly of ions from solution. Using cryotransmission electron microscopy, we found that template-directed calcium carbonate formation starts with the formation of prenucleation clusters. Their aggregation leads to the nucleation of amorphous nanoparticles in solution. These nanoparticles assemble at the template and, after reaching a critical size, develop dynamic crystalline domains, one of which is selectively stabilized by the template. Our findings have implications for template-directed mineral formation in biological as well as in synthetic systems.