A New Model for Virtual Radiometers

2012 ◽  
Author(s):  
Isaac L. Hunsaker ◽  
David J. Glaze ◽  
Jeremy N. Thornock ◽  
Philip J. Smith
Keyword(s):  
High Accuracy ◽  
Radiative Fluxes ◽  
New Model ◽  
Nuclear Security ◽  
Wholly Owned Subsidiary ◽  
Structured Meshes ◽  
Tracing Algorithm ◽  
Validation Testing ◽  
The U.S ◽  
Good Agreement

There exists a general need to compare radiative fluxes from experimental radiometers with fluxes computed in Thermal/Fluid simulations. Unfortunately, typical numerical simulation suites lack the ability to predict fluxes to objects with small view angles thus preventing validation of simulation results. A new model has been developed that allows users to specify arbitrary view angles, orientations, and locations of multiple radiometers, and receive as the output, high-accuracy radiative fluxes to these radiometers. This virtual radiometer model incorporates a reverse monte-carlo ray tracing algorithm adapted to meet these user specifications and runs on both unstructured and structured meshes. Verification testing of the model demonstrated the expected order of convergence. Validation testing showed good agreement between calculated fluxes from the model and measured fluxes from radiometers used in propellant fires. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DEAC0494AL85000.

scholarly journals The Stationary Concentrated Vortex Model

Climate ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 39
Author(s):  
Oleg Onishchenko ◽  
Viktor Fedun ◽  
Wendell Horton ◽  
Oleg Pokhotelov ◽  
Natalia Astafieva ◽  
...  
Keyword(s):  
Vortex Structure ◽  
Radial Direction ◽  
Symmetry Axis ◽  
Outer Part ◽  
Vertical Direction ◽  
Axially Symmetric ◽  
New Model ◽  
Vortex Model ◽  
Axis Of Symmetry ◽  
Good Agreement

A new model of an axially-symmetric stationary concentrated vortex for an inviscid incompressible flow is presented as an exact solution of the Euler equations. In this new model, the vortex is exponentially localised, not only in the radial direction, but also in height. This new model of stationary concentrated vortex arises when the radial flow, which concentrates vorticity in a narrow column around the axis of symmetry, is balanced by vortex advection along the symmetry axis. Unlike previous models, vortex velocity, vorticity and pressure are characterised not only by a characteristic vortex radius, but also by a characteristic vortex height. The vortex structure in the radial direction has two distinct regions defined by the internal and external parts: in the inner part the vortex flow is directed upward, and in the outer part it is downward. The vortex structure in the vertical direction can be divided into the bottom and top regions. At the bottom of the vortex the flow is centripetal and at the top it is centrifugal. Furthermore, at the top of the vortex the previously ascending fluid starts to descend. It is shown that this new model of a vortex is in good agreement with the results of field observations of dust vortices in the Earth’s atmosphere.

scholarly journals Thermal conductivity of unsaturated clay-rocks

2010 ◽  
Vol 14 (1) ◽  
pp. 91-98 ◽  
Author(s):  
D. Jougnot ◽  
A. Revil
Keyword(s):  
Thermal Conductivity ◽  
Porous Material ◽  
Solid Phase ◽  
Model Parameters ◽  
Electrical Parameters ◽  
New Model ◽  
Unsaturated Clay ◽  
Unsaturated Porous Material ◽  
Clay Rocks ◽  
Good Agreement

Abstract. The parameters used to describe the electrical conductivity of a porous material can be used to describe also its thermal conductivity. A new relationship is developed to connect the thermal conductivity of an unsaturated porous material to the thermal conductivity of the different phases of the composite, and two electrical parameters called the first and second Archie's exponents. A good agreement is obtained between the new model and thermal conductivity measurements performed using packs of glass beads and core samples of the Callovo-Oxfordian clay-rocks at different saturations of the water phase. We showed that the three model parameters optimised to fit the new model against experimental data (namely the thermal conductivity of the solid phase and the two Archie's exponents) are consistent with independent estimates. We also observed that the anisotropy of the effective thermal conductivity of the Callovo-Oxfordian clay-rock was mainly due to the anisotropy of the thermal conductivity of the solid phase.

scholarly journals Contact angle of water on iron ore fines: Measurement and analysis

2015 ◽  
Vol 51 (1) ◽  
pp. 33-40 ◽  
Author(s):  
X.B. Huang ◽  
X X.W. ◽  
J.J. Song ◽  
C.G. Bai ◽  
R.D. Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Iron Ore ◽  
Contact Angles ◽  
Physical Parameters ◽  
Iron Ores ◽  
New Model ◽  
Pressure Method ◽  
Measurement And Analysis ◽  
Iron Ore Fines ◽  
Good Agreement

The relative contact angle (?RCA) for seven iron ore fines was measured by using Washburn Osmotic Pressure method under laboratory conditions. By choosing cyclohexane as the reference that can perfectly wet iron ore particles, the relative contact angles were measured and varied from 57? to 73?. With the volume % of goethite (?G) as the variable, a new model for relative contact angle was developed. The expected relative contact angle for pure goethite is about 56?, while that for goethite free samples is about 77?. Physical properties, such as surface morphology (SMI) and pore volume (Vpore) can influence the relative contact angle. The ?G can be expressed as a function of SMI and VPore. Thus, we inferred that the relative contact angle is a function of ?G for the iron ores used. The measured relative contact angles were found to be in good agreement (Radj 2 >0.97) with the calculated ones based on the research from Iveson, et al. (2004). Comparing with the model developed by Iveson et al.(2004), the new model for contact angle proposed in this paper is similar, but more detailed with two meaningful physical parameters. The modification of physicochemical properties on iron ores would be another topic in the further study on granulation.

scholarly journals Body composition analysis by DEXA by using dynamically changing samarium filtration

1997 ◽  
Vol 82 (4) ◽  
pp. 1200-1209 ◽  
Author(s):  
Anders Gotfredsen ◽  
Lene Bæksgaard ◽  
And Jannik Hilsted
Keyword(s):  
Body Composition ◽  
Reference Method ◽  
High Accuracy ◽  
Composition Analysis ◽  
Fat Percentage ◽  
Beam Hardening ◽  
Tissue Mass ◽  
Body Composition Analysis ◽  
Filtration System ◽  
Good Agreement

Gotfredsen, Anders, Lene Bæksgaard, and Jannik Hilsted.Body composition analysis by DEXA by using dynamically changing samarium filtration. J. Appl. Physiol.82(4): 1200–1209, 1997.—Dual-energy X-ray absorptiometry (DEXA) has a high accuracy for body composition analysis but is influenced by beam hardening and other error sources in the extremes of measurement. To compensate for beam hardening, the Norland XR-36 introduces a dynamically changing samarium filtration system, which depends on the current-absorber thickness. With this system we found a good agreement ( r = 0.99) between reference and measured amounts of tissue or fat percentages in a plastic phantom and in smaller (∼0.5–4 kg) and larger (∼5–20 kg) piles of tissue (ox muscle and lard). Scans of six healthy volunteers covered with combinations of beef and lard (∼5–15 kg) showed a good agreement ( r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic filtration) has a high accuracy for body composition analysis. It has a potential for gaining status as a reference method in the future and may presently be used as a supplement to the traditional methods for body composition analysis.

scholarly journals Energy levels of one-dimensional anharmonic oscillator via neural networks

2019 ◽  
Vol 34 (12) ◽  
pp. 1950088 ◽  
Author(s):  
Halil Mutuk
Keyword(s):  
Neural Network ◽  
Field Theory ◽  
Anharmonic Oscillator ◽  
Energy Levels ◽  
High Accuracy ◽  
Network System ◽  
Quantum Field ◽  
One Dimensional ◽  
Neural Network System ◽  
Good Agreement

In this work, we obtained energy levels of one-dimensional quartic anharmonic oscillator by using neural network system. Quartic anharmonic oscillator is a very important tool in quantum mechanics and also in the quantum field theory. Our results are in good agreement in high accuracy with the reference studies.

Detecting Multiple Ground Contacts in Cloud-to-Ground Lightning Flashes

2009 ◽  
Vol 26 (11) ◽  
pp. 2392-2402 ◽  
Author(s):  
Christina A. Stall ◽  
Kenneth L. Cummins ◽  
E. Philip Krider ◽  
John A. Cramer
Keyword(s):  
Standard Deviation ◽  
Rise Time ◽  
Random Errors ◽  
Peak Current ◽  
Video Recordings ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
The U.S ◽  
Good Agreement ◽  
Cg Lightning

Abstract Video recordings of cloud-to-ground (CG) lightning flashes have been analyzed in conjunction with correlated stroke reports from the U.S. National Lightning Detection Network (NLDN) to determine whether the NLDN is capable of identifying the different ground contacts in CG flashes. For 39 negative CG flashes that were recorded on video near Tucson, Arizona, the NLDN-based horizontal distances between the first stroke and the 62 subsequent strokes remaining in a preexisting channel had a mean and standard deviation of 0.9 ± 0.8 km and a median of 0.7 km. The horizontal distances between the first stroke and the 59 new ground contacts (NGCs) had a mean and standard deviation of 2.3 ± 1.7 km and a median of 2.1 km. These results are in good agreement with prior measurements of the random errors in NLDN positions in southern Arizona as well as video- and thunder-based measurements of the distances between all ground contacts in Florida. In cases where the distances between ground contacts are small and obscured by random errors in the NLDN locations, measurements of the stroke rise time, estimated peak current, and stroke order can be utilized to enhance the ability of the NLDN to identify strokes that produce new ground terminations.

scholarly journals Compositional Dependence of Structural Properties of Prepared Alloys and Films

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
M. F. A. Alias ◽  
A. A. J. Al-Douri ◽  
E. M. N. Al-Fawadi ◽  
A. A. Alnajjar
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
High Accuracy ◽  
Compositional Dependence ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates ◽  
Different Temperatures ◽  
Good Agreement

Results of a study of alloys and films with various Pb content have been reported and discussed. Films of of thickness 1.5 μm have been deposited on glass substrates by flash thermal evaporation method at room temperature, under vacuum at constant deposition rate. These films were annealed under vacuum around 10−6Torr at different temperatures up to 523 K. The composition of the elements in alloys was determined by standard surfaces techniques such as atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF), and the results were found of high accuracy and in very good agreement with the theoretical values. The structure for alloys and films is determined by using X-ray diffraction. This measurement reveals that the structure is polycrystalline with cubic structure and there are strong peaks at the direction (200) and (111). The effect of heat treatment on the crystalline orientation, relative intensity, and grain size of films is presented.

Analysis and Validation of Cutting Forces Prediction Models in Micromachining

2006 ◽  
Vol 526 ◽  
pp. 13-18 ◽  
Author(s):  
H. Perez ◽  
Antonio Vizan Idoipe ◽  
J. Perez ◽  
J. Labarga
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Cutting Forces ◽  
Prediction Models ◽  
Precision Machining ◽  
New Model ◽  
Proposed Model ◽  
On Line ◽  
Machine Control ◽  
Good Agreement

Many investigations have been developed related to precision machining with features in the millimetre scale. In this paper different cutting force models for micromilling are analyzed and compared. A new model based on specific cutting force that also considers run-out errors has been developed. The estimated cutting forces obtained with this model had good agreement with the experimental data. Also, the proposed model allows to be implemented within the machine control for the on-line optimization of the micromilling process.

Analysis of the Electron Traps at the 4H-SiC/SiO2 Interface of a Gate Oxide Obtained by Wet Oxidation of a Nitrogen Pre-Implanted Layer

2009 ◽  
Vol 615-617 ◽  
pp. 533-536
Author(s):  
Ioana Pintilie ◽  
Francesco Moscatelli ◽  
Roberta Nipoti ◽  
Antonella Poggi ◽  
Sandro Solmi ◽  
...  
Keyword(s):  
Low Frequency ◽  
Gate Oxide ◽  
High Accuracy ◽  
Interface Trap Density ◽  
Interface Trap ◽  
High Concentration ◽  
Mos Capacitors ◽  
Order Of Magnitude ◽  
Good Agreement

This work is focusing on the effect of a high concentration of nitrogen (N) introduced by ion implantation at the SiO2/4H-SiC interface in MOS capacitors. The N implanted sample (Ninterface ~1x1019cm-3) is compared with a non-implanted one (Ninterface ~1x1016cm-3) by means of the electron interface trap density (Dit). The Dit is determined via High-Low frequency C-V method and Thermal Dielectric Relaxation Current (TDRC) technique. It is shown that the TDRC method, mainly used so far for determination of near interface oxide charges, can be exploited to gain information about the Dit too. The determined value of Dit in the N-implanted sample is nearly one order of magnitude lower than that in the sample without N implantation. Good agreement between the TDRC results and those obtained from High-Low frequency C-V measurements is obtained. Furthermore, the TDRC method shows a high accuracy and resolution of Dit evaluation in the region close to the majority carrier band edge and gives information about the traps located into the oxide.

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