15,501 research outputs found
Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles, volume 1
The efficiency of internal noise radiation through coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken to: (1) define the test parameters which influence the internal noise radiation; (2) develop a test methodology which could realistically be used to examine the effects of the test parameters; (3) and to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the in the jet nozzles. Noise transmission characteristics of a nozzle system were then investigated. In particular, the effects of fan nozzle convergence angle, core extention length to annulus height ratio, and flow Mach number and temperatures were studied. The results are presented as normalized directivity plots
The unreasonable effectiveness of equilibrium-like theory for interpreting non-equilibrium experiments
There has been great interest in applying the results of statistical
mechanics to single molecule experiements. Recent work has highlighted
so-called non-equilibrium work-energy relations and Fluctuation Theorems which
take on an equilibrium-like (time independent) form. Here I give a very simple
heuristic example where an equilibrium result (the barometric law for colloidal
particles) arises from theory describing the {\em thermodynamically}
non-equilibrium phenomenon of a single colloidal particle falling through
solution due to gravity. This simple result arises from the fact that the
particle, even while falling, is in {\em mechanical} equilibrium (gravitational
force equal the viscous drag force) at every instant. The results are
generalized by appeal to the central limit theorem. The resulting time
independent equations that hold for thermodynamically non-equilibrium (and even
non-stationary) processes offer great possibilities for rapid determination of
thermodynamic parameters from single molecule experiments.Comment: 6 page
First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System
First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control
System The roots of ATLAS (Argonne Tandem-Linac Accelerator System) date back
to the early 1960s. Located at the Argonne National Laboratory, the accelerator
has been designated a National User Facility, which focuses primarily on
heavy-ion nuclear physics. Like the accelerator it services, the control system
has been in a constant state of evolution. The present real-time portion of the
control system is based on the commercial product Vsystem [1]. While Vsystem
has always been capable of distributed I/O processing, the latest offering of
this product provides for the use of relatively inexpensive PC hardware and
software. This paper reviews the status of the ATLAS control system, and
describes first experiences with PC distributed I/O.Comment: ICALEPCS 2001 Conference, PSN WEAP027, 3 pages, 1 figur
Androhermaphrodites of Lychnis Alba
Lychnis alba was found to produce four categories of flowers; i.e. pistillate, staminate, gynohermaphrodite and androhermaphrodite. Hermaphrodites are formed when a rudimentary pistil (pistillodium) or stamens (staminodea) develop into mature organs on the ovaries of otherwise pistillate or staminate flowers. Androhermaphrodites, in particular, were studied and their structure and behavior found to be essentially similar to corresponding parts of regular staminate and pistillate flowers. Ovaries of androhermaphrodite flowers exhibited variations in style number ranging from one to five. Ovaries with two to five styles were self- or cross-fertile with any good Lychnis alba pollen. One-styled ovaries of androhermaphrodite flowers were of unusual interest because they occurred so commonly, showed a range of development from a pistillodium to a mature ovary, and because they were characteristically self- and cross-sterile
AIOps for a Cloud Object Storage Service
With the growing reliance on the ubiquitous availability of IT systems and
services, these systems become more global, scaled, and complex to operate. To
maintain business viability, IT service providers must put in place reliable
and cost efficient operations support. Artificial Intelligence for IT
Operations (AIOps) is a promising technology for alleviating operational
complexity of IT systems and services. AIOps platforms utilize big data,
machine learning and other advanced analytics technologies to enhance IT
operations with proactive actionable dynamic insight.
In this paper we share our experience applying the AIOps approach to a
production cloud object storage service to get actionable insights into
system's behavior and health. We describe a real-life production cloud scale
service and its operational data, present the AIOps platform we have created,
and show how it has helped us resolving operational pain points.Comment: 5 page
Literature searches and reviews related to the prevalence of food allergy in Europe
In 2011, the European Food Safety Authority (EFSA) received a mandate from the Food Safety Authority of Ireland (FSAI) to review the available scientific data on the prevalence of each food allergy in Europe, to derive threshold concentrations for each allergen in foods when possible, and to review the analytical methods available for the detection/quantification of food allergens. This report presents the findings of a series of systematic reviews of the literature related to these aims. Systematic searches of relevant bibliographic databases and the grey literature were conducted, studies were selected for inclusion according to pre-specified criteria, relevant data was extracted from all included studies, and the quality of included studies assessed. The first systematic review examined the literature on the prevalence of food allergy (IgE-mediated and non-IgE mediated) in different regions of the World and in individual European countries for different age groups in relation to each of the following food allergens: milk/dairy, eggs, cereals, peanuts, nuts, celery, crustaceans, fish, molluscs, soy, lupin, mustard and sesame. For each of these allergens changes in prevalence trends over time were also examined. Additionally, emerging food allergens in different European countries were identified. Of the 7333 articles identified by the searches, data from 92 studies was included, 52 of which reported on studies conducted within Europe. The second systematic review examined the effects of food processing on the allergenicity of foods in relation to each of the following food allergens: milk/dairy, eggs, cereals, peanuts, nuts, celery, crustaceans, fish, molluscs, soy, lupin, mustard and sesame. From 1040 articles identified by the searches, 25 studies were included in this review. The final systematic review examined the evidence regarding the new analytical methods available to analyse/detect the food allergens considered in the previous systematic reviews in processed foods. From 1475 articles identified by the searches, 84 studies were included
Seeing the smart city on Twitter: Colour and the affective territories of becoming smart
This paper pays attention to the immense and febrile field of digital image files which picture the smart city as they circulate on the social media platform Twitter. The paper considers tweeted images as an affective field in which flow and colour are especially generative. This luminescent field is territorialised into different, emergent forms of becoming âsmartâ. The paper identifies these territorialisations in two ways: firstly, by using the data visualisation software ImagePlot to create a visualisation of 9030 tweeted images related to smart cities; and secondly, by responding to the affective pushes of the image files thus visualised. It identifies two colours and three ways of affectively becoming smart: participating in smart, learning about smart, and anticipating smart, which are enacted with different distributions of mostly orange and blue images. The paper thus argues that debates about the power relations embedded in the smart city should consider the particular affective enactment of being smart that happens via social media. More generally, the paper concludes that geographers must pay more attention to the diverse and productive vitalities of social media platforms in urban life and that this will require experiment with methods that are responsive to specific digital qualities
On the temperature dependence of the symmetry energy
We perform large-scale shell model Monte Carlo (SMMC) calculations for many
nuclei in the mass range A=56-65 in the complete pfg_{9/2}d_{5/2} model space
using an effective quadrupole-quadrupole+pairing residual interaction. Our
calculations are performed at finite temperatures between T=0.33-2 MeV. Our
main focus is the temperature dependence of the symmetry energy which we
determine from the energy differences between various isobaric pairs with the
same pairing structure and at different temperatures. Our SMMC studies are
consistent with an increase of the symmetry energy with temperature. We also
investigate possible consequences for core-collapse supernovae events
Electronic compressibility of layer polarized bilayer graphene
We report on a capacitance study of dual gated bilayer graphene. The measured
capacitance allows us to probe the electronic compressibility as a function of
carrier density, temperature, and applied perpendicular electrical displacement
D. As a band gap is induced with increasing D, the compressibility minimum at
charge neutrality becomes deeper but remains finite, suggesting the presence of
localized states within the energy gap. Temperature dependent capacitance
measurements show that compressibility is sensitive to the intrinsic band gap.
For large displacements, an additional peak appears in the compressibility as a
function of density, corresponding to the presence of a 1-dimensional van Hove
singularity (vHs) at the band edge arising from the quartic bilayer graphene
band structure. For D > 0, the additional peak is observed only for electrons,
while D < 0 the peak appears only for holes. This asymmetry that can be
understood in terms of the finite interlayer separation and may be useful as a
direct probe of the layer polarization
The field theoretic derivation of the contact value theorem in planar geometries and its modification by the Casimir effect
The contact value theorem for Coulomb gases in planar or film-like geometries
is derived using a Hamiltonian field theoretic representation of the system.
The case where the film is enclosed by a material of different dielectric
constant to that of the film is shown to contain an additional Casimir-like
term which is generated by fluctuations of the electric potential about its
mean-field value.Comment: Link between Sine-Gordon and Coulomb gas pressures via subtraction of
self interaction terms included. Discussion of results within Debye-Huckel
approximation included. Added reference
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