Apparent Modulus of Elasticity of Dental Amalgams

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66932/2/10.1177_00220345750540043301.pd

Parameters that Affect the Color of Denture Resins

The effect of specular reflection, background color and specimen thickness on the color of four commercial denture resins was studied by reflection spectrophotometry. Higher values of luminous reflectance and excitation purity were obtained with a white than with a black background, whereas dominant wavelength was lowered slightly.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66710/2/10.1177_00220345770560110601.pd

Parameters that Affect the Color of Direct Restorative Resins

The effects of thickness, background color, specular reflection, and surface roughness on the color of five commercial restorative resins were studied by reflection spectrophotometry. As thickness increased, values of luminous reflectance and excitation purity increased for a black background but decreased for a white background. Opacity increased dramatically as thickness increased from 1.3 to 3.9 mm.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67249/2/10.1177_00220345780570090701.pd

Surface Failure of Commercial and Experimental Restorative Resins

The mode of surface failure of commercial and experimental restorative resins and composites was evaluated with a single-pass sliding test. The wear of restorative resins and composites is determined by the resistance of the material to penetration and by the mode of deformation during sliding.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67209/2/10.1177_00220345760550032201.pd

Practical Methodology for the Inclusion of Nonlinear Slosh Damping in the Stability Analysis of Liquid-Propelled Space Vehicles

A method is presented that allows for the prediction of the magnitude of limit cycles due to adverse control-slosh interaction in liquid propelled space vehicles using non-linear slosh damping. Such a method is an alternative to the industry practice of assuming linear damping and relying on: mechanical slosh baffles to achieve desired stability margins; accepting minimal slosh stability margins; or time domain non-linear analysis to accept time periods of poor stability. Sinusoidal input describing functional analysis is used to develop a relationship between the non-linear slosh damping and an equivalent linear damping at a given slosh amplitude. In addition, a more accurate analytical prediction of the danger zone for slosh mass locations in a vehicle under proportional and derivative attitude control is presented. This method is used in the control-slosh stability analysis of the NASA Space Launch System

Photochemical Rearrangements of 6/5 -Fused Cross-conjugated Cyclohexadiensnes in Protic Solvents

Irradiation of the ring A unsubstituted 6/5-fused cross-conjugated cyclohexadienone (1a) and its 2-methyl derivative (1b) in methanolic acetic acid yields, in addition to other products, novel tricyclononane derivatives which have been assigned the structures (3a) and (3b)