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Acoustic imaging of vapor bubbles through optically non-transparent media

Description: A preliminary investigation of the feasibility of acoustic imaging of vapor bubbles through optically nontransparent media is described. Measurements are reported showing the echo signals produced by air filled glass spheres of various sizes positioned in an aqueous medium as well as signals produced by actual vapor bubbles within a water filled steel pipe. In addition, the influence of the metallic wall thickness and material on the amplitude of the echo signals is investigated. Finally severa… more
Date: October 1, 1983
Creator: Kolbe, W.F.; Turko, B.T. & Leskovar, B.
Partner: UNT Libraries Government Documents Department
open access

Fast ultrasonic imaging in a liquid filled pipe

Description: A new method is described for the imaging of the interior of a liquid filled metallic pipe using acoustical techniques. The experimental system incorporates an array of 20 acoustical transducers and is capable of capturing the images of moving bubbles at a frame rate in excess of 300/s. The transducers are mounted circumferentially around the pipe. Each transducer is pulsed in sequence, and the echoes reflected from vapor bubbles in the interior are detected, digitized and processed by a comput… more
Date: October 1, 1985
Creator: Kolbe, W.F.; Turko, B.T. & Leskovar, B.
Partner: UNT Libraries Government Documents Department
open access

Kinetics of fission product release prior to fuel slumping

Description: This paper describes the primary physical/chemical models recently incorporated into a mechanistic code (FASTGRASS) for the estimation of fission product release from fuel, and compares predicted results with test data. The theory of noble gas behavior is discussed in relation to its effect on the release behavior of I, Cs, Te, Ba, and Sr. The behavior of these fission products in the presence of fuel liquefaction/dissolution and oxidation grain-growth phenomena is presented, as is the chemistr… more
Date: October 1, 1987
Creator: Rest, J.
Partner: UNT Libraries Government Documents Department
open access

Thermal-hydraulic studies on molten core-concrete interactions

Description: This report discusses studies carried out in connection with light water power reactor accidents. Recent assessments have indicated that the consequences of molten-core concrete interactions dominate the considerations of severe accidents. The two areas of interest that have been investigated are interlayer heat and mass transfer and liquid-liquid boiling. Interlayer heat and mass transfer refers to processes that occur within a core melt between the stratified, immiscible phases of core oxides… more
Date: October 1, 1986
Creator: Greene, G.A.
Partner: UNT Libraries Government Documents Department
open access

Bubbles and their implications for laser-fusion

Description: Bubbles are concentrations of electromagnetic energy in the region of the critical density that force out the plasma to form a void. Since the critical density surface is cratered, absorption may be greater than a smooth surface since a larger area will be available for absorption and the reflected light will have a large probability of restriking the critical density. The distance between bubbles is several wavelengths and consequently they may encourage Rayleigh--Taylor instabilities. The thr… more
Date: October 28, 1975
Creator: Estabrook, K. G. & Valeo, E. J.
Partner: UNT Libraries Government Documents Department
open access

Measurement and Analysis of Gas Bubbles Near a Reference Electrode in Aqueous Solutions

Description: Bubble size distributions (BSDs) near a reference electrode (RE) in aqueous glycerol solutions of an electrolyte NaCl have been investigated under various gas superficial velocities (U{sub S}). BSD and voltage reading of the solution were measured by using a high-speed digital camera and a pH/voltage meter, respectively. The results show that bubble size (b) increases with liquid viscosity ({mu}{sub c}) and U{sub S}. Self-similarity is seen and can be described by the log-normal form of the con… more
Date: October 1, 2005
Creator: Phongikaroon, Supathorn; Herrmann, Steve; Li, Shelly & Simpson, Michael
Partner: UNT Libraries Government Documents Department
open access

Microscopic Return Point Memory in Co/Pd Multilayer Films

Description: We report soft x-ray speckle metrology measurements of microscopic return point and complementary point memory in Co/Pd magnetic films having perpendicular anisotropy. We observe that the domains assemble into a common labyrinth phase with a period that varies by nearly a factor of two between initial reversal and fields near saturation. Unlike previous studies of similar systems, the ability of the film to reproduce its domain structure after magnetic cycling through saturation varies from loo… more
Date: October 1, 2009
Creator: Seu, K.A.; Su, R.; Roy, S.; Parks, D.; Shipton, E.; Fullerton, E.E. et al.
Partner: UNT Libraries Government Documents Department
open access

Development of Interfacial Structure in a Confined Air-Water Cap-Turbulent and Churn-Turbulent Flow

Description: The objective of the present work is to study and model the interfacial structure development of air-water two-phase flow in a confined test section. Experiments of a total of 9 flow conditions in a cap-turbulent and churn-turbulent flow regimes are carried out in a vertical air-water upward two-phase flow experimental loop with a test section of 20-cm in width and 1-cm in gap. The miniaturized four-sensor conductivity probes are used to measure local two-phase parameters at three different ele… more
Date: October 31, 2001
Creator: Sun, X.; Kim, S.; Cheng, L.; Ishii, M. & Beus, S.G.
Partner: UNT Libraries Government Documents Department
open access

Cap Bubble Drift Velocity in a Confined Test Section

Description: In the two-group interfacial area transport equation, bubbles are categorized into two groups, i.e., spherical/distorted bubbles as group 1 and cap/slug/churn-turbulent bubbles as group 2. The bubble rise velocities for both groups of bubbles may be estimated by the drift flux model by applying different distribution parameters and drift velocities for both groups. However, the drift velocity for group 2 bubbles is not always applicable (when the wall effect becomes important) as in the current… more
Date: October 9, 2002
Creator: Sun, Xiaodong; Kim, Seungjin; Ishii, Mamoru; Lincoln, Frank W. & Beus, Stephen G.
Partner: UNT Libraries Government Documents Department
open access

Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site

Description: In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except fo… more
Date: October 20, 1999
Creator: ANANTATMULA, R.P.
Partner: UNT Libraries Government Documents Department
open access

CNEA/ANL collaboration program to develop an optimized version of DART validation and assessment by means of U{sub 3}Si{sub x} and U{sub 3}O{sub 8-}Al dispersed CNEA miniplate irradiation behavior.

Description: The DART code is based upon a thermomechanical model that can predict swelling, recrystallization, fuel-meat interdiffusion and other issues related with MTR dispersed FE behavior under irradiation. As a part of a common effort to develop an optimized version of DART, a comparison between DART predictions and CNEA miniplates irradiation experimental data was made. The irradiation took place during 1981-82 for U3O8 miniplates and 1985-86 for U{sub 3}Si{sub x} at Oak Ridge Research Reactor (ORR).… more
Date: October 16, 1998
Creator: Solis, D.
Partner: UNT Libraries Government Documents Department
open access

Downward flow of water with entrained air in a nonuniformaly heated subdivided annulus

Description: This paper describes an experimental study in which water was fed to a vertical annulus, entraining air in downward flow. The annulus was subdivided by longitudinal fins into four subchannels and was heated with an azimuthally varying heat flux. A bypass was provided to simulate flow in parallel channels. For steady liquid flow, inlet temperature, and pressure boundary conditions, the power was increased until critical heat flux was reached. Overheating characteristics were grouped according to… more
Date: October 1, 1992
Creator: Johnston, B. S. & May, C. P.
Partner: UNT Libraries Government Documents Department
open access

Implicit Eulerian method for analyzing transient phenomena in fast reactors

Description: An Eulerian compressible hydrodynamic method is presented for analyzing transient phenomena in nuclear reactors following hypothetical excursions. The method uses the implicit integration scheme to solve nonlinear equations of fluid dynamics in conjunction with a thin-shell analysis to calculate the response of the wall boundary. Detailed formulations are given. Results are presented for two example problems and compared with available experimental data. 6 references. (auth)
Date: October 1, 1975
Creator: Wang, C. Y.
Partner: UNT Libraries Government Documents Department
open access

Kinetics of helium bubble formation in nuclear materials

Description: The formation and growth of helium bubbles due to self-irradiation in plutonium has been modeled by a discrete kinetic equations for the number densities of bubbles having k atoms. Analysis of these equations shows that the bubble size distribution function can be approximated by a composite of: (1) the solution of partial differential equations describing the continuum limit of the theory but corrected to take into account the effects of discreteness, and (2) a local expansion about the advanc… more
Date: October 13, 2005
Creator: Bonilla, L L; Carpio, A; Neu, J C & Wolfer, W G
Partner: UNT Libraries Government Documents Department
open access

A Very Deep Chandra Observation of the Perseus Cluster: Shocks, Ripples And Conduction

Description: We present the first results from a very deep Chandra X-ray observation of the core of the Perseus cluster of galaxies. A pressure map reveals a clear thick band of high pressure around the inner radio bubbles. The gas in the band must be expanding outward and the sharp front to it is identified as a shock front, yet we see no temperature jump across it; indeed there is more soft emission behind the shock than in front of it. We conclude that in this inner region either thermal conduction opera… more
Date: October 26, 2005
Creator: Fabian, A. C.; Sanders, Jeremy S.; Taylor, G. B.; Allen, S. W.; Crawford, C. S.; Johnstone, R. M. et al.
Partner: UNT Libraries Government Documents Department
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