American Psychological Association Commission on Violence and Youth.

Lists the membership of the commission and discusses its objective of analyzing the roles of perpetrators and victims of violence and the psychosocial consequences of witnessing violent acts and living with the constant threat of violence. The commission is using interdisciplinary expertise to examine the developmental and sustaining factors of violence, as well as frequently targeted groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improvement in the Reliability of Mechanical Flux Feed Systems for Continuous Slab-Casting Machine Molds

Metallurgist - We discuss the operating principle and design features for an improved mechanical flux feed system to be used in continuous slab-casting machine molds; this system provides increased...     

Relationship of TV viewing habits and aggressive behavior in children.

Information about TV habits, (a) length of time watched and (b) extent of violence in favorite programs, was obtained from 689 mothers and 522 fathers in individual interviews having to do with the psychosocial antecedents of aggressive behavior in their children. This information was related to ratings of aggressive behavior of 3rd-grade children made by their peers. It was found that there was a significant positive relationship between the violence ratings of favorite programs as reported by both mothers and fathers and aggressive behavior of boys as rated in school. Also there was a significant negative relation between total time watched by boys as reported by mothers and aggressive behavior. The results for fathers' reports in this latter case were in the same direction, although not significant. No consistent relationships were noted between girls' TV habits as reported by either mother or father and aggression as rated in school by the peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Television violence and aggression: The causal effect remains.

Replies to criticisms by G. Becker (1972), R. M. Kaplan (1972), and H. Kay (1972) on the article by L. D. Eron et al (see record 1973-09034-001) concerning television violence and aggression. There is no reason to change the conclusion that early exposure to TV violence probably has a causal influence on aggression in males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fast replacement of submersible tundish nozzles in a continuous slab-casting machine

The prospects for fast replacement of submersible tundish nozzles in a continuous slab-casting machine are assessed. It is shown that further improvement is required so as to increase the reliability. The operational forces in the drives of the submersible nozzles are studied experimentally, with different supporting structures in the casting system so as to ensure slipping friction and rolling friction between the supporting surface of the metal housing in the protective refractory component and the clamping elements. When flat sprung elements are replaced by rollers, the total drag on the submersible nozzles during fast replacement may be reduced from 0.6–1.3 to 0.4–1.0. That reduces the load on the hydraulic drive of the tundish casting system by a factor of 1.2–1.3 and also increases its fault-free life in long continuous-casting runs. The results are used in the design of an improved system for fast replacement of the submersible nozzles.     

Hydraulic simulation of the replacement of submerged nozzles in slab continuous casters

A physical model is used to study the effect of submerged nozzles during their replacement on the trajectory of motion of the metal streams in the mold of a slag continuous caster in the course of casting. Recommendations are made to decrease the time of action of this factor on the ingot formation conditions.     

Surface fatigue and wear of PVD coated punches during fine blanking operation

Performance of two different physical vapour deposited (PVD) TiCN and Alcrona® (AlCrN) coatings systems is under investigation. Coatings were deposited on the punches produced from the Böhler S390 Microclean steel. Two different surface preparation techniques were used – wet polishing (high surface roughness) and dry polishing (low surface roughness).Industrial trials of PVD coated punches in fine blanking operation were performed and studied. Wear of punches was analysed in regard to the punch geometry, position in the die and surface roughness, and measured after maximum 100,000 cycles at high loads.Punches with higher surface roughness seem to withstand numerous loading cycles with some traces of coating delamination and wear. On the other hand performance of PVD coatings with smaller surface roughness in a striking way was much worse.Comparative trials of the coatings surface fatigue wear and indentation surface fatigue testing were performed in the laboratory as well. In surface fatigue wear testing coatings were dynamically indented by ball (spherical) indenters made from conventional hardmetal (WC-6 wt.%). Testing parameters were identical to those of industrial trials. The Vickers diamond pyramid indenter was cyclically pressed with 500 N load at single point during indentation surface fatigue testing. Results are in agreement with surface fatigue wear tests results.Finally the microstructural investigations using SEM and XRD techniques were performed for better understanding of the surface fatigue and wear mechanisms during fine blanking process.Results of both trials are in good agreement and allow predicting performance of coatings.     

Short-term loss of strength of as-drawn silica optical fibers

It is established that the strength of as-drawn silica fibers exhibits a 15% drop for about an hour after drawing. The nature of this phenomenon is related to a change in the content of moisture in a polymer coating of the fiber. Based on analysis of the observed phenomenon, it is recommended to modify the process of silica-fiber drawing.     

Development of ultra wideband, high efficiency, distributed power amplifiers using discrete GaN HEMTs

This study describes the design and performance of a discrete ultra wideband GaN HEMT distributed power amplifier (DPA) with over 5 W (37 dBm) output power and a PAE exceeding 27 in the 0.02-3 GHz frequency range. The implemented DPA design is comprised of three discrete GaN HEMT devices. Its performance was enhanced using tapered drain lines and non-uniform gate capacitive coupling. The design methodology is based on both small and large signal analysis using harmonic balance technique, and their associated predicted and experimental results are discussed here in detail.