We analyze theoretically the subspace best approximating images of a convex Lambertian object under different distant illumination conditions. Since the lighting is an arbitrary function, the space of all possible images is formally infinite-dimensional. However, previous empirical work by Hallinan [7] and Epstein et al. [4] has shown that images of largely diffuse objects actually lie very clo...

Pyroplastic deformation is a distortion of the ceramic shape during the sintering process. It occurs because the flow of the vitreous phase at high temperature and the applied stress due to the weight of the product during sintering process. The aim of this paper deals with describing a numerical-experimental method to evaluate the pyroplastic deformation, to predict the anisotropic shrinkage a...

We show how Principal Component Analysis can be used to analyse the structure of Cepheid light curves. This method is more efficient than Fourier analysis at bringing out changes in light curve shape as a function of period. Using this technique, we study the shape of fundamental and first overtone mode Cepheid light curves in the Galaxy, LMC and SMC over a wide period range. For fundamentals, ...

Ring rolling is one of the most significant methods for producing rings with highly precise dimensions and superior qualities such as high strength uniformity, all accomplished without wasting any materials. In this article, we have achieved analytical formulas for calculating the pressure and shear friction over the contact arcs between the rollers and ring in the ring rolling process for the ...

Objectives: This study sought to assess the level of stress in general dentists in the 2nd district of Tehran city in 2014 to find out the stressors and suggest strategies to overcome them. Methods: This descriptive, analytical, cross-sectional study was conducted on 130 general dentists from the 2nd district of Tehran city selected via weighted randomization. Level of stress was assessed us...