1,721,036 research outputs found
Mathematical model for batch drying in an inert medium fluidized bed
No full textA modified three-phase model is proposed for batch drying of fine powders in an inert medium fluidized bed. The overall heat and mass transfer coefficients between the interstitial gas and solid phases have been determined by the proposed surface-stripping model in which the Blot number is a governing parameter. The effects of gas velocity, inlet gas temperature and mass ratio of starch to inert particles on the drying characteristics of starch in a 0.083 m ID x 0.80 m high medium fluidized bed have been determined. Based on the proposed model, the internal resistance of mass transfer at the powder is equal to the external resistance. The model predicts well the bed temperature, humidity of outlet gas, moisture content of solid particles, heat and mass transfer in an inert medium fluidized bed
Reference-free damage classification based on cluster analysis
No full textFiber-reinforced polymer (FRP) composite materials have been widely used for retrofitting civil infrastructure systems. The ultimate goal of this study was to develop an in-site non-destructive testing (NDT) technique that can continuously and autonomously inspect the bonding condition between a carbon FRP (CFRP) layer and a host reinforced concrete (RC) structure, when the CRFP layer is used for strengthening the RC structure. The uniqueness of this reference-free NDT is two-fold: First, features, which are sensitive to CFRP debonding but insensitive to operational and environmental variations of the structure, have been extracted only from current data without direct comparison with previously obtained baseline data. Second, damage classification is performed instantaneously without relying on predetermined decision boundaries. The extraction of the reference-free features is accomplished based on the concept of time reversal acoustics, and the instantaneous decision-making is achieved using cluster analysis. Monotonic and fatigue load tests of large-scale CFRP-strengthened RC beams are conducted to demonstrate the potential of the proposed reference-free debonding monitoring technique. Based on the experimental studies, it has been shown that the proposed reference-free NDT technique may minimize false alarms of debonding and unnecessary data interpretation by end users.This research was supported by an NSF Grant No. CMS-
0529208 and Pennsylvania Infrastructure Technology
Alliance (PITA) program, and Smart Infra-Structure
Technology Center (SISTeC). The authors also like to
thank Chiwon In, Seung Bum Kim, Kelly Cronin, and
Dena E. De Iuliis for assisting our experiments. The
second author would like to acknowledge the Electric
Power National Scholarship Program at the Ministry of Commerce, Industry and Energy (MOCIE) in Gwachon,
SouthKorea.The beam testing was assisted by Andrew
Zorn and Benjamin Reeve in theWatkins-Haggart
Structural Engineering Laboratory at the University of
Pittsburgh
Vibration analysis of the tension shadow mask with wire impact damping
No full textNon-linear vibration of the CRT shadow mask with impact damping wires is analyzed in consideration of the mask tension distribution and the effect of wire impact damping. A reduced order FEM model of the shadow mask is obtained from dynamic condensation of the mass and stiffness matrices, and damping wire is modelled using the lumped parameter method to effectively describe its contact interactions with the shadow mask. The non-linear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. The analysis model of the shadow mask with damping wires is experimentally verified through impact tests of shadow masks performed in a vacuum chamber. Using the validated analysis model of the shadow mask with damping wires, the 'design of experiments' technique is applied to search for the optimal damping wire configuration so that the vibration attenuation of the shadow mask is maximized. (C) 2002 Published by Elsevier Science Ltd
HEAT-TRANSFER AND HYDRODYNAMIC STUDIES ON 2-PHASE AND 3-PHASE FLUIDIZED-BEDS OF FLOATING BUBBLE BREAKERS
No full textKorea Science and Engineering Foundatio
Bubble breakage phenomena, phase holdups and mass transfer in three-phase fluidized beds with floating bubble breakers
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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