scholarly journals A preliminary evaluation of the thermal effects of the Ben Franklin Dam project on Columbia River temperatures below the Hanford Plant

1967 ◽  
Author(s):  
R.T. Jaske
Keyword(s):  
Thermal Effects ◽  
Columbia River ◽  
Preliminary Evaluation

A Preliminary Evaluation of a Generation IV Liquid Metal Fast Reactor Due to Sloshing and Thermal Stress

2009 ◽  
Author(s):  
Barbara Vezzoni ◽  
Rosa Lo Frano ◽  
Giuseppe Forasassi
Keyword(s):  
Thermal Effects ◽  
Thermal Analyses ◽  
Fluid Motion ◽  
Structural Response ◽  
Preliminary Evaluation ◽  
Structure Interaction ◽  
Liquid Free Surface ◽  
Set Up ◽  
Accident Conditions ◽  
Residual Heat

The aim of this paper is a preliminary evaluation of the load bearing capability of a generation IV molten metal cooled reactor (LMFR), with reference, as an example, to the ELSY project in the event of a safe shutdown earthquake (SSE). Two relevant safety aspects were considered and analyzed by means finite element (FEM) codes: the fluid-structure interaction and the high thermal loads due to the residual heat levels of the possible high burnup fuel. The first issue depends on the presence of a liquid free surface that especially in seismic accident conditions, allows for fluid motion (“sloshing”) and may have a significant influence on the reactor structures stress levels. The second aspect deals with the irradiated core heat source thermal effects after the reactor shutdown. In order to evaluate the reactor and internal components structural response capability for both high temperature and hydrodynamic loads, appropriate 3-D models were set up. Moreover preliminary thermal analyses were carried out by means of MCNPX and Origen2.2 codes in order to determine the transient input decay power after shutdown. The obtained preliminary results allowed to individuate the structures mostly affected by the assumed loading conditions in order to make possible an upgrading of the design geometry, should any be necessary, for the considered reactor design. The mentioned activities was a part of a CE funded 6th FWP.

Thermal Considerations in Lens Regulator Systems

1970 ◽  
Vol 28 ◽  
pp. 358-359
Author(s):  
K.C. Newton
Keyword(s):  
Electron Microscope ◽  
Thermal Effects ◽  
Environmental Control ◽  
Reference Networks ◽  
Better Than

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.

Direct measurement of electron-diffraction-pattern intensities using an energy loss spectrometer

1989 ◽  
Vol 47 ◽  
pp. 668-669
Author(s):  
A. G. Jackson ◽  
M. Rowe
Keyword(s):  
Thermal Effects ◽  
Dynamic Range ◽  
Scattering Amplitude ◽  
Dynamical Theory ◽  
Site Symmetry ◽  
Proof Of Concept ◽  
Parallel Acquisition ◽  
Kinematic Approximation ◽  
Speed Up ◽  
Structure Calculations

Diffraction intensities from intermetallic compounds are, in the kinematic approximation, proportional to the scattering amplitude from the element doing the scattering. More detailed calculations have shown that site symmetry and occupation by various atom species also affects the intensity in a diffracted beam. [1] Hence, by measuring the intensities of beams, or their ratios, the occupancy can be estimated. Measurement of the intensity values also allows structure calculations to be made to determine the spatial distribution of the potentials doing the scattering. Thermal effects are also present as a background contribution. Inelastic effects such as loss or absorption/excitation complicate the intensity behavior, and dynamical theory is required to estimate the intensity value.The dynamic range of currents in diffracted beams can be 104or 105:1. Hence, detection of such information requires a means for collecting the intensity over a signal-to-noise range beyond that obtainable with a single film plate, which has a S/N of about 103:1. Although such a collection system is not available currently, a simple system consisting of instrumentation on an existing STEM can be used as a proof of concept which has a S/N of about 255:1, limited by the 8 bit pixel attributes used in the electronics. Use of 24 bit pixel attributes would easily allowthe desired noise range to be attained in the processing instrumentation. The S/N of the scintillator used by the photoelectron sensor is about 106 to 1, well beyond the S/N goal. The trade-off that must be made is the time for acquiring the signal, since the pattern can be obtained in seconds using film plates, compared to 10 to 20 minutes for a pattern to be acquired using the digital scan. Parallel acquisition would, of course, speed up this process immensely.

Preliminary Evaluation of a Weibull Function for Fitting Slow-Component Eye Velocity over the Time Course of Caloric-Induced Nystagmus

1989 ◽  
Vol 32 (3) ◽  
pp. 681-687 ◽  
Author(s):  
C. Formby ◽  
B. Albritton ◽  
I. M. Rivera
Keyword(s):  
Time Course ◽  
Slow Component ◽  
Weibull Function ◽  
Preliminary Evaluation ◽  
Mathematical Function ◽  
Before And After ◽  
Best Fitting ◽  
Eye Velocity ◽  
Fitting Parameters ◽  
Weibull Equation

We describe preliminary attempts to fit a mathematical function to the slow-component eye velocity (SCV) over the time course of caloric-induced nystagmus. Initially, we consider a Weibull equation with three parameters. These parameters are estimated by a least-squares procedure to fit digitized SCV data. We present examples of SCV data and fitted curves to show how adjustments in the parameters of the model affect the fitted curve. The best fitting parameters are presented for curves fit to 120 warm caloric responses. The fitting parameters and the efficacy of the fitted curves are compared before and after the SCV data were smoothed to reduce response variability. We also consider a more flexible four-parameter Weibull equation that, for 98% of the smoothed caloric responses, yields fits that describe the data more precisely than a line through the mean. Finally, we consider advantages and problems in fitting the Weibull function to caloric data.

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