Vertex Reconstruction Using a Single Layer Silicon Detector

Typical vertex finding algorithms use reconstructed tracks, registered in a multi-layer detector, which directly point to the common point of origin. A detector with a single layer of silicon sensors registers the passage of primary particles only in one place. Nevertheless, the information available from these hits can also be used to estimate the vertex position, when the geometrical properties of silicon sensors and the measured ionization energy losses of the particles are fully exploited. In this paper the algorithm used for this purpose in the PHOBOS experiment is described. The vertex reconstruction performance is studied using simulations and compared with results obtained from real data. The very large acceptance of a single-layered multiplicity detector permits vertex reconstruction for low multiplicity events where other methods, using small acceptance subdetectors, fail because of insufficient number of registered primary tracks.Comment: accepted for publication in Nucl. Instr. Meth.

Questioning, exploring, narrating and playing in the control room to maintain system safety

Systems whose design is primarily aimed at ensuring efficient, effective and safe working, such as control rooms, have traditionally been evaluated in terms of criteria that correspond directly to those values: functional correctness, time to complete tasks, etc. This paper reports on a study of control room working that identified other factors that contributed directly to overall system safety. These factors included the ability of staff to manage uncertainty, to learn in an exploratory way, to reflect on their actions, and to engage in problem-solving that has many of the hallmarks of playing puzzles which, in turn, supports exploratory learning. These factors, while currently difficult to measure or explicitly design for, must be recognized and valued in design

Verification-guided modelling of salience and cognitive load

Well-designed interfaces use procedural and sensory cues to increase the cognitive salience of appropriate actions. However, empirical studies suggest that cognitive load can influence the strength of those cues. We formalise the relationship between salience and cognitive load revealed by empirical data. We add these rules to our abstract cognitive architecture, based on higher-order logic and developed for the formal verification of usability properties. The interface of a fire engine dispatch task from the empirical studies is then formally modelled and verified. The outcomes of this verification and their comparison with the empirical data provide a way of assessing our salience and load rules. They also guide further iterative refinements of these rules. Furthermore, the juxtaposition of the outcomes of formal analysis and empirical studies suggests new experimental hypotheses, thus providing input to researchers in cognitive science

Consequences of energy conservation in relativistic heavy-ion collisions

Complete characterization of particle production and emission in relativistic heavy-ion collisions is in general not feasible experimentally. This work demonstrates, however, that the availability of essentially complete pseudorapidity distributions for charged particles allows for a reliable estimate of the average transverse momenta and energy of emitted particles by requiring energy conservation in the process. The results of such an analysis for Au+Au collisions at sqrt{s_{NN}}= 130 and 200 GeV are compared with measurements of mean-p_T and mean-E_T in regions where such measurements are available. The mean-p_T dependence on pseudorapidity for Au+Au collisions at 130 and 200 GeV is given for different collision centralities.Comment: 8 pages, 8 figures, Submitted to Phys. Rev.

Geoneutrinos in Borexino

This paper describes the Borexino detector and the high-radiopurity studies and tests that are integral part of the Borexino technology and development. The application of Borexino to the detection and studies of geoneutrinos is discussed.Comment: Conference: Neutrino Geophysics Honolulu, Hawaii December 14-16, 200

Поэтонимология: из заметок о метаязыке науки

Представлены сведения о развитии метаязыка поэтонимологии как науки о собственных именах в литературных произведениях, определены его термино-логические составляющие. Сформулирована позиция автора, относительно характера терминосистемы ономастики. Основное внимание уделено некоторым аспектам развития собственно ономастической части понятий и терминов поэтонимологии. Показан базовый характер термина "поэтоним" и возможности его использования для формирования специальной поэтонимологической терминологии. Рассмотрены достоинства и недостатки различных наименований дисциплины, изучающей собственные имена художественных произведений.У статі йдеться про розвиток метамови поетонімології як науки про власні імена у літературних творах. Висвітлена позиція автора щодо характеру терміносистеми ономастики. Приділено увагу деяким аспектам розвитку власне ономастичної складової терміносистеми поетонімології. Показаний базовий характер терміна "поетонім" і можливості його використання.The article is devoted to the development of meta-language of poetonymology as a sciences about the proper names in literary works. Author's position is lighted up in relation to the system of onomastic terms. Attention is spared to some aspects of development actually onomastic constituent of poetonymologic term system. Base character of "poetonym" as a term and possibilities of its use are showed

Fundamental study of flow field generated by rotorcraft blades using wide-field shadowgraph

The vortex trajectory and vortex wake generated by helicopter rotors are visualized using a wide-field shadowgraph technique. Use of a retro-reflective Scotchlite screen makes it possible to investigate the flow field generated by full-scale rotors. Tip vortex trajectories are visible in shadowgraphs for a range of tip Mach number of 0.38 to 0.60. The effect of the angle of attack is substantial. At an angle of attack greater than 8 degrees, the visibility of the vortex core is significant even at relatively low tip Mach numbers. The theoretical analysis of the sensitivity is carried out for a rotating blade. This analysis demonstrates that the sensitivity decreases with increasing dimensionless core radius and increases with increasing tip Mach number. The threshold value of the sensitivity is found to be 0.0015, below which the vortex core is not visible and above which it is visible. The effect of the optical path length is also discussed. Based on this investigation, it is concluded that the application of this wide-field shadowgraph technique to a large wind tunnel test should be feasible. In addition, two simultaneous shadowgraph views would allow three-dimensional reconstruction of vortex trajectories

Using ‘TRAPS’ (Transect Recording and Processing System) in Woody Weed Control Studies in Australia

The ‘TRAPS’ (Transect Recording And Processing System) methodology has proven to be a powerful and versatile tool for studying the effects of various woody weed control strategies in studies carried out in Queensland, Australia. ‘TRAPS’ allows the tracking of individual woody plants even when destructive control techniques such as bulldozing, ploughing and burning are used. This methodology also allows the investigator to discriminate between plants present before any treatment is imposed and plants recruited after the treatment

Convective heat transfer in a convergent- divergent nozzle

Turbulent flow convective heat transfer in convergent-divergent nozzle