Let X and Y be proper birational varieties, say with only rational double points over a perfect field k of positive characteristic. If X lifts to Wn(k), is it true that Y has the same lifting property? This is true for smooth surfaces, but we show by example that this is false for smooth varieties in higher dimension, and for surfaces with canonical singularities. We also answer a stacky analog...

We study the extension generated by the x-coordinates of the petorsion points of an elliptic curve over a function field of characteristic p. If S → C is a non-isotrivial elliptic surface in characteristic p with a pe-torsion section, then for pe > 11 our results imply restrictions on the genus, the gonality, and the p-rank of the base curve C, whereas for pe ≤ 11 such a surface can be construc...

In this paper we give the first example of a surface bundle over a surface with at least three fiberings. In fact, for each n ≥ 3 we construct 4-manifolds E admitting at least n distinct fiberings pi : E → Σgi as a surface bundle over a surface with base and fiber both closed surfaces of negative Euler characteristic. We give examples of surface bundles admitting multiple fiberings for which th...

Icings on moving machinery, such as wind turbines and aircraft wings, degrade their performance safety. Ultrasonic vibration is considered one of the deicing methods. In this research, simulations experiments are carried out to explore effect ultrasonic adhesive characteristic ice aluminum alloy plates. Harmonic response analyses conducted analyze changing distributions shear stresses at interf...

A skilled welder determines the weld joint penetration from his/her observation of the weld pool surface during the welding process. This paper addresses the characterization of the 3D weld pool surface in gas tungsten arc welding (GTAW), i.e., extracting a set of characteristic parameters from the 3D weld pool surface to determine the backside bead width that measures the degree of weld joint ...