Origin and reduction of wakefields in photonic crystal accelerator cavities

Photonic crystal (PhC) defect cavities that support an accelerating mode tend to trap unwanted higher-order modes (HOMs) corresponding to zero-group-velocity PhC lattice modes at the top of the bandgap. The effect is explained quite generally from photonic band and perturbation theoretical arguments. Transverse wakefields resulting from this effect are observed in a hybrid dielectric PhC accelerating cavity based on a triangular lattice of sapphire rods. These wakefields are, on average, an order of magnitude higher than those in the waveguide-damped Compact Linear Collider (CLIC) copper cavities. The avoidance of translational symmetry (and, thus, the bandgap concept) can dramatically improve HOM damping in PhC-based structures.Comment: 11 pages, 18 figures, 2 table

Search Theory and U-Boats in the Bay of Biscay

Threats to our nation\u27s resources and forces are becoming increasingly lethal and mobile. Therefore, our ability to locate and interdict these threats is more important than ever. Search theory is one tool that is vital to countering the increasing threat. This research presents a multi-agent simulation, built around the Allied search for U-boats in the Bay of Biscay during World War II, which extends several classic search theory algorithms. Comparison of techniques is based on the effectiveness of finding high- valued, mobile assets. A JAVA-based multi-agent simulation model is designed, built and tested, and used to demonstrate the existence of differing emergent behaviors between search patterns currently used by the United States military

The Child\u27s Perceptual Awareness of His Own Segmented Facial Parts

The purpose of this paper is to demonstrate the developmental abilities of young middle-class, caucasian children to perceptually discriminate their own segmented facial parts. The Segmented Facial Parts Test, which utilized a black and white, 8 inch by 10 inch photograph, was developed by the investigator as a part of the study. it was designed to explore degrees of developmental variance on facial awareness tasks. The SFPT was incorporated as the testing instrument. Children ages 8 1/2, 6 1/2 and 4 1/2 years were examined on nine facial segment tasks. Sociological, psychological and psychiatric theories were employed in order to explain the possible interconnections between body awareness and self concept maturation and enhancement. Whole-part perception theory was also clarified and substantiated by this study. Results indicated that mental and chronological maturity are significant variables affecting the amount of facial awareness occurring in young children. Young males and females exhibit no substantial differences in their segmented facial parts awareness. According to this study, younger children adhere to a holistic style of perceptual functioning. Part perception becomes more and more apparent as the child\u27s age increases

NASCAR Winston Cup Drivers: A Sociological Profile

NASCAR racing is a popular competitive pastime for many Americans. This study examines Winston Cup stock car drivers from sociological perspective, analyzing their demographic information and their racing motivations and history. The researcher used a 33 item questionnaire to develop a qualitative and quantitative profile of a “typical” 1987 Winston Cup driver. The researcher obtained data on 77 Winston Cup racers during the 1987 season. Information included drivers’ age, race, gender, marital status, number of children, education, place of birth, place of upbringing, family involvement in racing, motivation for racing, fitness training, athletic participation, racing experience, career satisfaction, and feelings of success. Results include indications that NASCAR racing is a white, male dominated sport, and that prior family involvement in racing and spending one’s childhood in the southeastern US are influencing factors in becoming a professional racer. On average, Winston Cup drivers need 20 years of racing experience, however, colleges do not provide racing training and so most professional racers do not pursue higher education. Suggestions for further study include investigating the gender divide in racing and a sociological study of “racing communities” at Winston Cup tracks

Affective Symmetry: Affect and Networks in Blizzard’s StarCraft II: Legacy of the Void

This paper employs a social network analysis of StarCraft II: Legacy of the Void to examine how the single-player campaign structures a largely non-player character (NPC) community. This analysis, which includes a convergence of social network analysis and affect theory, explores the dynamic interactive gameplay network experience of Legacy of the Void. Additionally, the data visualizations map the complex network of communal interactions that exist even in the single player campaign through the virtual community of NPCs into which a player immerses him or herself

A Two-Coordinate Nickel Imido Complex That Effects C−H Amination

An exceptionally low coordinate nickel imido complex, (IPr*)Ni═N(dmp) (2) (dmp = 2,6-dimesitylphenyl), has been prepared by the elimination of N_2 from a bulky aryl azide in its reaction with (IPr*)Ni(η^6-C_7H_8) (1). The solid-state structure of 2 features two-coordinate nickel with a linear C−Ni−N core and a short Ni−N distance, both indicative of multiple-bond character. Computational studies using density functional theory showed a Ni═N bond dominated by Ni(dπ)−N(pπ) interactions, resulting in two nearly degenerate singly occupied molecular orbitals (SOMOs) that are Ni−N π* in character. Reaction of 2 with CO resulted in nitrene-group transfer to form (dmp)NCO and (IPr*)Ni(CO)_3 (3). Net C−H insertion was observed in the reaction of 2 with ethene, forming the vinylamine (dmp)NH(CH═CH_2) (5) via an azanickelacyclobutane intermediate, (IPr*)Ni{N,C:κ^2-N(dmp)CH_2CH_2} (4)