93-GT-300 CALIBRATING ULTRASONIC IMAGES FOR THE NDE OF STRUCTURAL MATERIALS

ABSTRACT Ultrasonic imaging is taking a larger and larger role in the NDE of turbine engine materials and in support of fracture mechanics calculations. It is also playing an increasing role in quality and process control

Advances in Transient-Liquid-Phase Bonding of Ultra-high Temperature ZrC Ceramics

AbstractFull exploitation of the many attractive engineering properties of ultra-high temperature ceramics (UHTCs) requires that they can be joined. This paper explores progress in identifying joining strategies based on the use of transient liquid phases (TLPs). Wetting studies are used to explore the suitability of specific liquids for joining, while bonding studies provide the ultimate test. Sintering aids in the UHTC provide a major potential obstacle to successful joining, and dissolved impurities in the TLP can also complicate the joining process. Nonetheless, we show that well-bonding interfaces can be achieved when ZrC ceramics are bonded at 1673 K using a Ni/Nb/Ni multilayer interlayer

Individualization as driving force of clustering phenomena in humans

One of the most intriguing dynamics in biological systems is the emergence of clustering, the self-organization into separated agglomerations of individuals. Several theories have been developed to explain clustering in, for instance, multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of fish, and animal herds. A persistent puzzle, however, is clustering of opinions in human populations. The puzzle is particularly pressing if opinions vary continuously, such as the degree to which citizens are in favor of or against a vaccination program. Existing opinion formation models suggest that "monoculture" is unavoidable in the long run, unless subsets of the population are perfectly separated from each other. Yet, social diversity is a robust empirical phenomenon, although perfect separation is hardly possible in an increasingly connected world. Considering randomness did not overcome the theoretical shortcomings so far. Small perturbations of individual opinions trigger social influence cascades that inevitably lead to monoculture, while larger noise disrupts opinion clusters and results in rampant individualism without any social structure. Our solution of the puzzle builds on recent empirical research, combining the integrative tendencies of social influence with the disintegrative effects of individualization. A key element of the new computational model is an adaptive kind of noise. We conduct simulation experiments to demonstrate that with this kind of noise, a third phase besides individualism and monoculture becomes possible, characterized by the formation of metastable clusters with diversity between and consensus within clusters. When clusters are small, individualization tendencies are too weak to prohibit a fusion of clusters. When clusters grow too large, however, individualization increases in strength, which promotes their splitting.Comment: 12 pages, 4 figure

Can Internet Ads Serve as an Indicator of Homeownership Rates?

In this paper, we propose an indicator of the homeownership rate based on Internet ads offering the housing for rent and sale. We constructed the HOR estimate using the number of ads in four different markets (flats for rent, flats for sale, houses for rent, and houses for sale). Our HOR indicator was tested using data of German NUTS1 and planning (ROR) regions. The correlation between our estimate of the HOR and the alternative HOR figures varies between 0.834 and 0.874 at NUTS1 level and is 0.761 at the ROR level. All correlation coefficients are statistically significant. Our HOR estimate is particularly highly correlated with the official HOR figures. Thus, it is shown that our Internet-based indices could serve as a good indicator of the homeownership rate in German regions

Private Enforcement, Corruption, and Antitrust Design

Recent adoption of competition laws across the globe has highlighted the importance of institutional considerations for antitrust effectiveness and the need for comparative institutional analyses of antitrust that extend beyond matters of substantive law. Contributing to the resulting nascent research agenda, we examine how the rationale for enabling versus precluding private antitrust enforcement as one salient choice in antitrust design depends on whether antitrust enforcement is corruption-free or plagued by corruption. Contingent on the nature of adjudicatory bias, bribery either discourages private antitrust lawsuits or incentivizes firms to engage in frivolous litigation. Corruption expectedly reduces the effectiveness of antitrust enforcement at deterring antitrust violations. Yet private antitrust enforcement as a complement to public enforcement can be social welfare-enhancing even in the presence of corruption. Under some circumstances, corruption actually increases the relative social desirability of private antitrust enforcement. Our analysis highlights that the appropriate design of antitrust institutions is context-specific