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Dust mobilization in a vacuum vessel is one of the key issues endangering the security of the International Thermonuclear Experimental Reactor (ITER) in case of loss of vacuum accidents. The turbulent behavior of particles in turbulent flows has to be modeled for successful numerical simulations about particle mobilization. In this study a Lagrangian approach is adopted to formulate the particle transport especially for dust-dilute flows mostly encountered in the vacuum vessel of ITER. Based on the logic frame of the approach and the used computational fluid dynamics (CFD) computer code in the study, a hybrid turbulent particle dispersion model is proposed. The hybrid model features both a deterministic separated flow model and a stochastic separated flow (SSF) model which are two popular turbulent dispersion models applied in particle simulations, and takes the advantages of the both models. The proposed model is implemented into the particle model of the CFD code successfully and the simulation results are verified against the experimental data. The verifications manifest the validities of the proposed model In this paper general information about the work of dust mobilization is introduced and the particle turbulent dispersion models are reviewed briefly at first. The hybrid model is then proposed based on the SSF model. An experiment about particle dispersions in an advective wind channel flow with decaying turbulence in the streamwise direction is reviewed in the third section. In the following section about model verification, the decaying turbulence parameters in the channel flow are verified against the experimental data as the first step, and the parameters about the particle dispersions in the verified flow field are then verified against the data. The work is concluded finally. [DOI: 10.1115/1.2983142]

Male circumcision employed as a prophylactic surgical intervention for HIV transmission reduction has been publicized in the media following recent results from observational trials conducted in Africa. Yet in all [...]

Cancer has been arguably the most feared disease in the United States for the past several decades. Now, as the baby boom generation starts to inch past middle age, a [...]

Commercial spectrophotometers typically use absorption-based wavelength calibration reference materials to provide wavelength accuracy for their applications. Low-mass fractions of holmium oxide ([Ho.sub.2][O.sub.3]) in dilute acidic aqueous solution and in glass matrixes have been favored for use as wavelength calibration materials on the basis of spectral coverage and absorption band shape. Both aqueous and glass [Ho.sub.2][O.sub.3] reference materials are available commercially and through various National Metrology Institutes (NMIs). Three NMIs of the North American Cooperation in Metrology (NORAMET) have evaluated the performance of [Ho.sup.3+](aq)-based Certified Reference Materials (CRMs) under 'routine' operating conditions using commercial instrumentation. The study was not intended to intercompare national wavelength scales but to demonstrate comparability of wavelength measurements among the participants and between two versions of the CRMs. It was also designed to acquire data from a variety of spectrophotometers for use in a NIST study of wavelength assignment algorithms and to provide a basis for a possible reassessment of NIST-certified [Ho.sup.3+](aq) band locations. The resulting data show a substantial level of agreement among laboratories, instruments, CRM preparations, and peak-location algorithms. At the same time, it is demonstrated that the wavelength comparability of the five participating instruments can actually be improved by calibrating all of the instruments to the consensus [Ho.sup.3+](aq) band locations. This finding supports the value of absorption-based wavelength standards for calibrating absorption spectrophotometers. Coupled with the demonstrated robustness of the band position values with respect to preparation and measurement conditions, it also supports the concept of extending the present approach to additional NMIs in order to certify properly prepared dilute acidic [Ho.sub.2][O.sub.3] solution as an intrinsic wavelength standard.

1. Introduction Absorbance spectroscopy is an essential measurement tool for the measurement and analysis of proteins [1] and nucleic acids [2]. However, these substances are often only available in very [...]

The intrinsic wavelength scale in a modern reference laser-controlled Michelson interferometer - sometimes referred to as the Connes advantage - offers excellent wavelength accuracy with relative ease. Truly superb wavelength accuracy, with total relative uncertainty in line position of the order of several parts in [10.sup.8], should be within reach with single-point, multiplicative calibration. The need for correction of the wavelength scale arises from two practical effects: the use of a finite aperture, from which off-axis rays propagate through the interferometer, and imperfect geometric alignment of the sample beam with the reference beam and the optical axis of the moving mirror. Although an analytical correction can be made for the finite-aperture effect, calibration with a trusted wavelength standard is typically used to accomplish both corrections. Practical aspects of accurate calibration of an interferometer in the UV-visible region are discussed. Critical issues regarding accurate use of a standard external to the sample source and the evaluation and selection of an appropriate standard are addressed. Anomalous results for two different potential wavelength standards measured by Fabry-Perot interferometry (At II and 198Hg I) are observed. Key words: Wavelength calibration, Fourier-transform spectroscopy, wavelength accuracy, wavelength standards, inductively coupled-plasma spectroscopy, spectral interferences, spectral atlas.

As Mars Observer closed in on the red planet last month, Alden Albee, the mission's project scientist, thought about calling Science to discuss the possibility of publishing a report of [...]

Colleagues of this year's Nobelists were pleased but not surprised by the news from Stockholm last week; all of the recipients had made seminal contributions to their fields. Perhaps the [...]

There are times when scientists would prefer to be wrong. Such was the case last week as Ivor van Heerden and other researchers reflected upon the devastation that Hurricane Katrina [...]

In 1980, Adrienne Salm, then a fledgling neuroscience graduate student at Michigan State University, attended her first Society for Neuroscience meeting. Participants by the thousands were rushing through the corridors [...]

Navigating the interstates from New York to San Francisco is a tough job for a driver - but it's easy compared to what the neurons of the developing nervous system [...]

Three new measurements peg the celebrated Hubble constant at values high enough to give theorists nightmares. Is the debate finally over? Don't bet on it In life, it has been [...]

There's a boom in new U.S. telescope construction, but this richness is deceptive--there may be no new money to run the new scopes. The result: a looming battle over resources [...]

Rough seas are pounding against the National Oceanic and Atmospheric Administration (NOAA) these days, as waves of criticism have battered plans to rejuvenate its aging oceanographic fleet. Over the past [...]

Cambridge, Massachusetts--Excitedly talking about plans for her next child, Lynn Andrea Stein doesn't even pause when a robot the size of a hat box scurries by the open door of [...]

Back in the 1940s and 50s, when the first antibiotics such as penicillin began making their way into clinical use, they were hailed as miracle drugs - and rightly so. [...]

The Marine Biological Laboratory has been home (at least temporarily)to more Nobel Prize-winners than perhaps any other U.S. institution. But it has recently hit rough waters WOODS HOLE, MASSACHUSETTS - [...]

From inflammation to cancer, the common cold to blood clotting, the potential of treatment based on 'sticky' molecules is thrilling industry Slightly more than a decade ago, the cell adhesion [...]

The potential prize would be great: the first glimpses of gravitational waves. But a messy dispute at Caltech has again raised the question of whether it's too long a shot [...]

An aging explorer gone to pieces, the deep-sea research submersible Alvin recently sat high and dry in a garage at Cape Cod's Woods Hole Oceanographic Institution (WHOI). In for its [...]

Cell biologists are getting a better view of how the internal structure of the nucleus may influence gene replication and activity In high school - or even college - biology, [...]

A few weeks ago, the American Paralysis Association (APA) celebrated its 10th anniversary with a 2-day scientific meeting.[*] And yes, celebrated is the appropriate word. For while researchers have not [...]

The tools and ingredients for making this first atom of antimatter are in hand; now researchers need to choose the right recipe Dreams of antimatter have been troubling physicists' sleep [...]

You've hung that Ph.D., framed and laminated, right next to the old bachelor's degree. That piece of sheepskin is proof positive that you've mastered some arcane piece of science, perhaps [...]

Less is more, exult researchers, as mice with punched-out genes make their mark on fields such as immunology and developmental biology Genetic engineering may be all the rage today, but [...]

A number-crunching brand of chemistry bypasses the traditional laboratory. Its practitioners create and study new molecules without ever leaving their computer terminals The traditional picture of chemistry--white-coated scientists at black [...]