20,358 research outputs found
Aspects of Coulomb damping in rotors supported on hydrodynamic bearings
The paper is concerned with the effect of friction in drive couplings on the non-sychronous whirling of a shaft. A simplified model is used to demonstrate the effect of large coupling misalignments on the stability of the system. It is concluded that provided these misalignments are large enough, the system becomes totally stable provided the shaft is supported on bearings exhibiting a viscous damping capacity
CAT-generating mechanisms
The development of instability configurations; the transition from unstable growth of these configurations into turbulence; a description of the nature of that turbulence; the question of decay of turbulence; and the existence of what is called fossil turbulence are discussed
Honeylocust Twig-gall Midge (Diptera: Cecidomyiidae) in Michigan
Emergence and oviposition data were gathered for Neolasioptera brevis, a recently described pest of honeylocust. In 1984 the insects first emerged on 21 May and first oviposited on 4 June; in 1985 they first emerged on 28 April and first oviposited between 5-20 May. Average raceme length at emergence and at oviposition were 2.7 and 4.4 cm in 1984 and 2.6 and 4.8 cm in 1985. Approximate duration of the emergence period was one week. In 1985 observed oviposition wounds averaged 0.5/cm
Geometrical relations and plethysms in the Homfly skein of the annulus
The oriented framed Homfly skein C of the annulus provides the natural
parameter space for the Homfly satellite invariants of a knot. It contains a
submodule C+ isomorphic to the algebra of the symmetric functions.
We collect and expand formulae relating elements expressed in terms of
symmetric functions to Turaev's geometrical basis of C+. We reformulate the
formulae of Rosso and Jones for quantum sl(N) invariants of cables in terms of
plethysms of symmetric functions, and use the connection between quantum sl(N)
invariants and C+ to give a formula for the satellite of a cable as an element
of C+. We then analyse the case where a cable is decorated by the pattern which
corresponds to a power sum in the symmetric function interpretation of C+ to
get direct relations between the Homfly invariants of some diagrams decorated
by power sums.Comment: 28 pages, 15 figure
Theoretical study of the mechanisms of fatigue in photomultipliers, phase 2 Final report
Fatigue testing of photomultipliers with gallium phosphide dynode
Pressure and velocity measurements in a three-dimensional wall jet
The effects on the flow fields of varying the ratio of the velocity at the exit plane of the nozzle to the outer tunnel flow are reported. The pressure-velocity correlations are taken and some trends are discussed. Emphasis is placed on comparing the coherence between the fluctuating pressure and velocity fields at various locations in the different flow configurations
An experimental investigation of an axisymmetric jet in a coflowing airstream
The flow development of an axisymmetric jet exhausting into a moving airstream has been studied. The jet has a Reynolds number of 22,600, and the ratio of the jet velocity to the wind tunnel velocity is 5.1 to 1. The flow field of the axisymmetric jet was examined at locations varying from approximately zero to eight diameters downstream of the orifice. Of primary concern at each downstream location was the mapping of the one point statistical properties of the flow, including mean velocity, turbulent intensity, and intermittency. Autocorrelations and power spectral density curves were determined for both the fluctuating velocity field and the concentration signal at various distances from the jet's center line for different downstream locations. A laser Doppler velocimeter, using a phase locked loop processor, was used to make the desired velocity field measurements which were compared with hot wire anemometer and pressure probe data
Chrono: A System for Normalizing Temporal Expressions
The Chrono System: Chrono is a hybrid rule-based and machine learning system written in Python and built from the ground up to identify temporal expressions in text and normalizes them into the SCATE schema. Input text is preprocessed using Python’s NLTK package, and is run through each of the four primary modules highlighted here. Note that Chrono does not remove stopwords because they add temporal information and context, and Chrono does not tokenize sentences. Output is an Anafora XML file with annotated SCATE entities. After minor parsing logic adjustments, Chrono has emerged as the top performing system for SemEval 2018 Task 6. Chrono is available on GitHub at https://github.com/AmyOlex/Chrono.
Future Work: Chrono is still under development. Future improvements will include: additional entity parsing, like “event”; evaluating the impact of sentence tokenization; implement an ensemble ML module that utilizes all four ML methods for disambiguation; extract temporal phrase parsing algorithm to be stand-alone and compare to similar systems; evaluate performance on THYME medical corpus; migrate to UIMA framework and implement Ruta Rules for portability and easier customization
Fracture clinic redesign reduces the cost of outpatient orthopaedic trauma care
Objectives: “Virtual fracture clinics” have been reported as a safe and effective alternative to the traditional fracture clinic. Robust protocols are used to identify cases that do not require further review, with the remainder triaged to the most appropriate subspecialist at the optimum time for review. The objective of this study was to perform a “top-down” analysis of the cost effectiveness of this virtual fracture clinic pathway.
Methods: National Health Service financial returns relating to our institution were examined for the time period 2009 to 2014 which spanned the service redesign.
Results: The total staffing costs rose by 4% over the time period (from ÂŁ1 744 933 to ÂŁ1 811 301) compared with a national increase of 16%. The total outpatient department rate of attendance fell by 15% compared with a national fall of 5%. Had our local costs increased in line with the national average, an excess expenditure of ÂŁ212 705 would have been required for staffing costs.
Conclusions: The virtual fracture clinic system was associated with less overall use of staff resources in comparison to national cost data. Adoption of this system nationally may have the potential to achieve significant cost savings
Blood Money: A Study of the Effect of Fighting on Player Salaries in the National Hockey League
Fighting has been a centerpiece of the National Hockey League since it was formed in 1917. Although rules have been introduced regulating the physicality of play in the NHL, fighting is demanded—and encouraged—by fans and players alike. Fans have long been attracted to the violence of professional hockey; previous studies have documented that professional hockey is a “blood sport” that generates revenues with violence. This research investigates the effect of fighting on player salaries in the NHL, examining the way in which fighting has become a strategic element of the game, describing the way players enforce their own “Code” of hockey rules and police the ice in ways referees cannot, and comparing the salaries of fighters and skilled players to determine how players in different roles are valued
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