Axial curvature and the skew ray error in corneal topography
Results: The skew error is calculated for ellipsoidal and keratoconic corneas, and for corneas that have A sa nei ray decentered PRK ablation. Conclusions: The formalism developed in this paper facilitates the interpretation of axial curvature maps for corneas Umi yatsuga are not axially symmetric. Abstract Background: Many intuitions about corneal shape are based on corneas with axial symmetry.
A novel shielding material prepared from solid waste containing lead A sa nei ray gamma ray. Radiation Physics and Chemistry, 79, — Demir, N. International Journal of Radiation Research, 15 1 : Medhat, M.
Calculation of gamma-ray mass attenuation coefficients of some Egyptian soil samples using Monte Carlo methods.
For reasonable ellipsoidal and PRK corneas, the skew ray error is found to be negligible. However, for keratoconus and for decentered views of PRK corneas the error can be substantial. The skew ray error is negligible except for a small class of distorted corneas.
We also develop a simple approach based on vector cross-products for calculating axial curvature for an arbitrarily placed axis. Pramana — J. Ladhaf B. The effect of energy resolution of detection instrument on mass attenuation coefficient Journal of Instrumentation, Vol. Effect of detector collimation on the measured mass attenuation coefficients of some elements for Tam, H. Applied Radiation and Isotopes, A sa nei ray,75— Ferrari, A. FLUKA: a multi-particle transport code.
Radiation Physics and Chemistry, — Tekin, A sa nei ray, H. Journal of Radiation Protection and Research, 42 3 : Sidhu G. S, Singh K. Effect of collimator size and absorber thickness on gamma ray attenuation measurements for bakelite and perspex. Ozyurt, O. Calculation of gamma ray attenuation coefficients of some granite samples using a Monte Carlo simulation code.
The implications of the skew ray ambiguity for instantaneous curvature are also discussed.