Common-value all-pay auctions with asymmetric information

We study two-player common-value all-pay auctions in which the players have ex-ante asymmetric information represented by finite connected partitions of the set of states of nature. Our focus is on a family of such auctions in which no player has an information advantage over his opponent. We find sufficient conditions for the existence of equilibrium with monotone strategies, and show that such an equilibrium is unique. We further show that the ex-ante distribution of equilibrium effort is the same for every player (and hence the players’ expected efforts are equal), although their expected payoffs are different and they do not have the same ex-ante probability of winning.     

On semi-rational finite simple groups

An element of a group G is called semi-rational if all generators of \(\langle x\rangle \) lie in the union of two conjugacy classes of G. If all elements of G are semi-rational, then G is called a semi-rational group. In this paper, we determine all semi-rational simple groups. Our study in this article generalises Feit and Seitz’s result (Ill J Math 33(1):103–131, 1989) to semi-rational groups.     

Ultrasonic detection of microstructure changes in cast iron

Ultrasonic waves are monitored to detect the microstructure changes in cast iron. Specimens are made from nonalloyed spheroidal graphite cast iron (before and after heat treatment), eutectoid carbon steel (0.8% C), and ingot iron. The ultrasonic longitudinal wave speed increased with increase in the graphite shape factor, pearlite volume fraction, specific length of grain boundaries and cementite-ferrite interface boundaries. Decrease in the wave speed corresponds to increase in the graphite volume fraction, graphite precipitates and austenitizing temperature and time.     

Unsteadiness of the shock wave structure in attached and separated compression ramp flows

Wall pressure fluctuations have been measured upstream of the corner-line in several two dimensional, adiabatic, compression ramp flows. The nominal freestream Mach number was 3 and the Reynolds number, based on boundary layer thickness, was 1.4 million. The measurements show that the shockwave structure is unsteady in both separated and attached flows, resulting in a region in which the wall pressure signal is intermittent. Statistical properties of this intermittent region, and of the separated flow, are presented and correlated with results from other studies.     

Porcelain tile surface modification with isocyanate coupling agent: interactions between EVA modified mortar and silane improving adherence

Adhesion between tiles and mortar is of paramount importance to the overall stability of ceramic tile systems. The interfaces between ceramic tiles and polymer‐modified Portland cement mortar are derived from several physical and chemical phenomena that take place during their formation. From the chemical perspective, weak forces are expected to occur preferably at the tiles and polymer‐modified Portland cement mortar interfaces. Therefore, the purpose of this study was to promote a new chemical functionalization of ceramic tile surfaces by modifying with isocyanate‐trialkoxysilane coupling agent in order to enhance the interfacial adhesion with poly (ethylene‐co‐vinyl acetate), EVA, polymer‐modified mortar. Pull‐off tests and Fourier Transformed Infrared Spectroscopy (FTIR), using the Attenuated Total Reflectance method, were carried out in order to characterize the system. The bond strength results have provided evidence toward improvements in adherence at the tile–polymer modified mortar interface, thus reflecting the development of urethane linkages between silane and EVA polymer, as detected by FTIR. Copyright © 2010 John Wiley & Sons, Ltd.     

Self-trapping of optical beams through thermophoresis

We demonstrate, theoretically and experimentally, self-trapping of optical beams in nanoparticle suspensions by virtue of thermophoresis. We use light to control the local concentration of nanoparticles, and increase their density at the center of the optical beam, thereby increasing the effective refractive index in the beam vicinity, causing the beam to self-trap.