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Articles 61 - 84 of 84
Full-Text Articles in Nuclear Engineering
X-Ray Digital Industrial Radiography (Dir) For Local Liquid Velocity (Vll) Measurement In Trickle Bed Reactors (Tbrs): Validation Of The Technique, K. A. M. Salleh, M. F. A. Rahman, Hyoung-Koo Lee, Muthanna H. Al-Dahhan
X-Ray Digital Industrial Radiography (Dir) For Local Liquid Velocity (Vll) Measurement In Trickle Bed Reactors (Tbrs): Validation Of The Technique, K. A. M. Salleh, M. F. A. Rahman, Hyoung-Koo Lee, Muthanna H. Al-Dahhan
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Local liquid velocity measurements in Trickle Bed Reactors (TBRs) are one of the essential components in its hydrodynamic studies. These measurements are used to effectively determine a reactor's operating condition. This study was conducted to validate a newly developed technique that combines Digital Industrial Radiography (DIR) with Particle Tracking Velocimetry (PTV) to measure the Local Liquid Velocity (VLL) inside TBRs. Three millimeter-sized Expanded Polystyrene (EPS) beads were used as packing material. Three validation procedures were designed to test the newly developed technique. All procedures and statistical approaches provided strong evidence that the technique can be used to measure …
Detector Response Function Of An Energy-Resolved Cdte Single Photon Counting Detector, Xin Liu, Hyoung Koo Lee
Detector Response Function Of An Energy-Resolved Cdte Single Photon Counting Detector, Xin Liu, Hyoung Koo Lee
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
BACKGROUND: While spectral CT using single photon counting detector has shown a number of advantages in diagnostic imaging, knowledge of the detector response function of an energy-resolved detector is needed to correct the signal bias and reconstruct the image more accurately.
Neutron Irradiation Effects On Domain Wall Mobility And Reversibility In Lead Zirconate Titanate Thin Films, Joseph T. Graham, Geoff L. Brennecka, Paulo Ferreira, Leo Small, David Duquette, Christopher Apblett, Sheldon Landsberger, Jon F. Ihlefeld
Neutron Irradiation Effects On Domain Wall Mobility And Reversibility In Lead Zirconate Titanate Thin Films, Joseph T. Graham, Geoff L. Brennecka, Paulo Ferreira, Leo Small, David Duquette, Christopher Apblett, Sheldon Landsberger, Jon F. Ihlefeld
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr0.52Ti0.48O3 films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16± 0.03) x 1015 cm-2. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was …
Method And System For Scatter Correction In X-Ray Imaging, X. Wu, J. Hsieh, P. Sainath, Xin Liu
Method And System For Scatter Correction In X-Ray Imaging, X. Wu, J. Hsieh, P. Sainath, Xin Liu
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Approaches for deriving scatter information using inverse tracking of scattered X-rays is disclosed. In certain embodiments scattered rays are tracked from respective locations on a detector to a source of the X-ray radiation, as opposed to tracking schemes that proceed from the source to the detector. In one such approach, the inverse tracking is implemented using a density integrated volume that reduces the integration steps performed.
Method And Apparatus For Adaptive Scatter Correction, Xin Liu, J. Hsieh, X. Wu
Method And Apparatus For Adaptive Scatter Correction, Xin Liu, J. Hsieh, X. Wu
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
A CT system includes a rotatable gantry having an opening to receive an object to be scanned, an x-ray source configured to project an x-ray beam toward the object having a primary intensity, a detector configured to detect high frequency electromagnetic energy passing through the object and output imaging data, and a data acquisition system (DAS) connected to the detector and configured to receive the imaging data. The system also includes a computer programmed to obtain image projection data of the object from the DAS, correct the projection data using a scatter function that is based at least on a …
Optical Microresonator Based On Hollow Sphere With Porous Wall For Chemical Sensing, Hanzheng Wang, Lei Yuan, Cheol Woon Kim, Qun Han, Tao Wei, Xinwei Lan, Hai Xiao
Optical Microresonator Based On Hollow Sphere With Porous Wall For Chemical Sensing, Hanzheng Wang, Lei Yuan, Cheol Woon Kim, Qun Han, Tao Wei, Xinwei Lan, Hai Xiao
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
A porous-wall hollow glass microsphere (PW-HGM) was investigated as an optical resonator for chemical vapor sensing. a single mode optical fiber taper was used to interrogate the micro resonator. Adsorption of chemical molecules into the nanosized pores induced a refractive index change of the thin wall and thus a shift in its resonance spectrum. the PW-HGM resonator had shown higher vapor detection sensitivity in comparison with a solid microsphere under similar test conditions. © 2011 Optical Society of America.
Interaction Between Supersonic Disintegrating Liquid Jets And Their Shock Waves, K.-S. Im, S.-K. Cheong, Xin Liu, J. Wang, M.-C. Lai, M. W. Tate, A. Ercan, M. J. Renzi, D. R. Schuette, S. M. Gruner
Interaction Between Supersonic Disintegrating Liquid Jets And Their Shock Waves, K.-S. Im, S.-K. Cheong, Xin Liu, J. Wang, M.-C. Lai, M. W. Tate, A. Ercan, M. J. Renzi, D. R. Schuette, S. M. Gruner
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The use of additional spectral filtration for dual-energy (DE) imaging using a dual-source CT (DSCT) system was investigated and its effect on the material-specific DEratio was evaluated for several clinically relevant materials. The x-ray spectra, data acquisition, and reconstruction processes for a DSCT system (Siemens Definition) were simulated using information provided by the system manufacturer, resulting in virtual DE images. The factory-installed filtration for the 80 kV spectrum was left unchanged to avoid any further reductions in tube output, and only the filtration for the high-energy spectrum was modified. Only practical single-element filter materials within the atomic number range of …
System And Method For Quantitative Imaging Of Chemical Composition To Decompose More Than Two Materials, Xin Liu, L. Yu, C. H. Mccollough
System And Method For Quantitative Imaging Of Chemical Composition To Decompose More Than Two Materials, Xin Liu, L. Yu, C. H. Mccollough
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
A system and method for decomposing more than two materials in an imaging object includes performing a CT imaging acquisition of a portion of an imaging object using at least two energy levels to acquire imaging data associated with each of the at least two energy levels. A total mass attenuation of the imaging data is expressed as a weighted sum of constituent element mass attenuation coefficients and an effective atomic number and density of the constituent elements in the portion of the imaging object is determined by one of a number of methods. Accordingly, concentration of the constituent elements …
System And Method For Quantitative Imaging Of Chemical Composition To Decompose Multiple Materials, Xin Liu, L. Yu, C. H. Mccollough
System And Method For Quantitative Imaging Of Chemical Composition To Decompose Multiple Materials, Xin Liu, L. Yu, C. H. Mccollough
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The present invention provides a material decomposition method capable of determining the distribution of density and constituent material concentration throughout an imaged object. The concentration, in the form of a mass fraction, mass percent, weight fraction, or weight percent, is determined from CT images acquired at different energy levels. The ratio of attenuation coefficients associated with one energy level to attenuation coefficients associated with another energy level is determined and used as an index in a lookup table to determine the concentration of a given material throughout the imaged object.
Preliminary Evidence Of Field Induced Rhenium Etching By Xef₂ At High Vacuum, M. Aghazarian, D. N. Ruzic, Carlos Henry Castano Giraldo
Preliminary Evidence Of Field Induced Rhenium Etching By Xef₂ At High Vacuum, M. Aghazarian, D. N. Ruzic, Carlos Henry Castano Giraldo
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Preliminary evidence of enhanced etching of rhenium by XeF2 under the influence of an electric field (3.36 GV/m) is presented. Scanning electron microscope photographs of sharp rhenium tips show etching of at least 0.40 µm ±0.07 in 32 min at the point of maximum electric field, indicating a field enhanced etching rate of 13 nm/min ±2. A control experiment shows a maximum spontaneous etching of rhenium by XeF2 of 0.1 µm ±0.07 in 30 min, indicating a maximum possible spontaneous etching rate of rhenium by XeF2 of 3 nm/min ±2. The spontaneous rate of tungsten by XeF2 reported in the …
Reactivity Control Schemes For Fast Spectrum Space Nuclear Reactors, Aaron E. Craft, Jeffrey C. King
Reactivity Control Schemes For Fast Spectrum Space Nuclear Reactors, Aaron E. Craft, Jeffrey C. King
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Several different reactivity control schemes are considered for future space nuclear reactor power systems. Each of these control schemes uses a combination of boron carbide absorbers and/or beryllium oxide reflectors to achieve sufficient reactivity swing to keep the reactor subcritical during launch and to provide sufficient excess reactivity to operate the reactor over its expected 7-15 year lifetime. The size and shape of the control system directly impacts the size and mass of the space reactor's reflector and shadow shield, leading to a tradeoff between reactivity swing and total system mass. This paper presents a trade study of drum, shutter, …
Phantom For Evaluating Accuracy Of Image Registration Software, B. Y. Choe, H. S. Jin, R. H. Juh, Hyoung-Koo Lee, J. Y. Song, T. S. Suh
Phantom For Evaluating Accuracy Of Image Registration Software, B. Y. Choe, H. S. Jin, R. H. Juh, Hyoung-Koo Lee, J. Y. Song, T. S. Suh
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Provided is a phantom for evaluating the accuracy of image registration software based on a result of matching tomograms of a predetermined position of the phantom, taken using two or more imaging apparatuses. Accordingly, it is possible to more efficiently evaluate the accuracy of the image registration software by comparing the tomograms with one another using a three-dimensional analysis. In addition, it is possible to facilitate the comparison of the tomograms with one another by installing a plurality of indicating bars in the phantom so that their cross sections can appear on each of the tomograms.
Reduced Shell Model Calculations Of 111Sb And 112Sb, E. Dikmen, T. Akyürek
Reduced Shell Model Calculations Of 111Sb And 112Sb, E. Dikmen, T. Akyürek
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The low-lying states of the mid-heavy odd-even 111Sb and odd-odd 112Sb isotopes are calculated for the first time within the shell model framework. The shell model calculations have been carried out within the reduced model space including the single particle orbits 1d5/2, 0g7/2, 1d3/2, 2s1/2. We obtain the energy spectra for the 111Sb and 112Sb isotopes in the reduced model space by using CD-Bonn two-body effective nucleon-nucleon interaction. The energy spectra are compared to the experimental results to give some discussion about the low-lying states of 111Sb and 112Sb. © 2007 Chinese Physical Society and IOP Publishing Ltd.
Gamma-Ray Induced Photoconductivity In Pyrex, Quartz, And Vycor, Shoaib Usman, Lubna Shoaib, James N. Anno
Gamma-Ray Induced Photoconductivity In Pyrex, Quartz, And Vycor, Shoaib Usman, Lubna Shoaib, James N. Anno
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Results of an experimental investigation are reported on photoconductive response of Pyrex, Quartz and Vycor. This research was conducted as a feasibility study for developing a new gamma dose measurement device based on the principle of photoconductivity. However, data collected in this study are equally valuable for various other applications where these materials are to be used in high radiation field. Our experiments and analyzes indicated that the selected dosimeter materials exhibit photoconductivity and respond to changes in gamma dose rate within a useful range. Pyrex glass suffered radiation damage at a relatively high dose rate of 0.25 Gys/sup -1/. …
Niel Calculations For High-Energy Heavy Ions, John W. Wilson, I. Jun, M. A. Xapsos, E. A. Burke, F. F. Badavi, L. W. Townsend
Niel Calculations For High-Energy Heavy Ions, John W. Wilson, I. Jun, M. A. Xapsos, E. A. Burke, F. F. Badavi, L. W. Townsend
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Calculations of NIEL are reported for heavy ions prominent in the space environment for energies ranging from 200 MeV per nucleon to 2 GeV per nucleon.
An Integral Form Of The Variational Nodal Method, M. A. Smith, G. Palmiotti, E. E. Lewis, Nicholas Tsoulfanidis
An Integral Form Of The Variational Nodal Method, M. A. Smith, G. Palmiotti, E. E. Lewis, Nicholas Tsoulfanidis
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
An integral form of the variational nodal method is formulated, implemented, and tested. the method combines an integral transport treatment of the even-parity flux within the spatial node with an odd-parity spherical harmonics expansion of the Lagrange multipliers at the node interfaces. the response matrices that result from this formulation are compatible with those in the VARIANT code at Argonne National Laboratory. Spatial discretization within each node allows for accurate treatment of homogeneous or heterogeneous node geometries. the integral method is implemented in Cartesian x-y geometry and applied to three benchmark problems. the method's accuracy is compared to that of …
A Finite Subelement Generalization Of The Variational Nodal Method, M. A. Smith, Nicholas Tsoulfanidis, E. E. Lewis, G. Palmiotti, T. A. Taiwo
A Finite Subelement Generalization Of The Variational Nodal Method, M. A. Smith, Nicholas Tsoulfanidis, E. E. Lewis, G. Palmiotti, T. A. Taiwo
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The variational nodal method is generalized by dividing each spatial node into a number of triangular finite elements designated as subelements. the finite subelement trial functions allow for explicit geometry representations within each node, thus eliminating the need for nodal homogenization. the method is implemented within the Argonne National Laboratory code VARIANT and applied to two-dimensional multigroup problems. Eigenvalue and pin-power results are presented for a four-assembly Organization for Economic Cooperation and Development/Nuclear Energy Agency benchmark problem containing enriched UO2 and mixed oxide fuel pins. Our seven-group model combines spherical or simplified spherical harmonic approximations in angle with isoparametric linear …
Radiation Resistance Testing Of Mosfet And Cmos As A Means Of Risk Management, Akira Tokuhiro, Massimo F. Bertino
Radiation Resistance Testing Of Mosfet And Cmos As A Means Of Risk Management, Akira Tokuhiro, Massimo F. Bertino
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Whether for military, research (space, accelerator physics) and/or civilian use, risk avoidance against radiation-induced damage is not possible with COTS parts. Thus the sensible approach is risk management. We recommend a sensible risk management approach as follows: 1) know the radiation environment of the intended application to the extent possible; 2) know the effects of ionizing radiation on the component(s) of interest; 3) know the requirements of the application; 4) identify the candidate or chosen components; 5) test the components; 6) design-in safety factor margins to the extent possible.
Traditional Signal Pattern Recognition Versus Artificial Neural Networks For Nuclear Plant Diagnostics, Shahla Keyvan
Traditional Signal Pattern Recognition Versus Artificial Neural Networks For Nuclear Plant Diagnostics, Shahla Keyvan
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
This paper introduces a new tool based on a traditional noise analysis technique for monitoring reactor components' signal condition. It also presents the performance of artificial neural networks for pattern recognition to the same set of reactor signals and provides a comparison of these two techniques. Reactor pump signals from the Experimental Breeder Reactor (EBR-II) are utilized here. Collected signals such as pump power, pump speed, and pump pressure are obtained from already installed sensors in the reactor. The signals utilized are collected signals as well as generated signals simulating the pump shaft degradation progress. From the study of time …
Nuclear Fuel Pellet Inspection Using Artificial Neural Networks, Shahla Keyvan, Xiaolong Song, Mark Kelly
Nuclear Fuel Pellet Inspection Using Artificial Neural Networks, Shahla Keyvan, Xiaolong Song, Mark Kelly
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Nuclear fuel must be of high quality before being placed into service in a reactor. Fuel vendors currently use manual inspection for quality control of fabricated nuclear fuel pellets. In order to reduce workers' exposure to radiation and increase the inspection accuracy and speed, the feasibility of automation of fuel pellet inspection using artificial neural networks (ANNs) is studied in this paper. Three kinds of neural network architectures are examined for evaluation of the ANN performance in proper classification of good versus bad pellets. Two supervised neural networks, back-propagation and fuzzy ARTMAP, and one unsupervised neural network called ART2-A are …
Spherical Harmonics - Finite Element Treatment Of Neutron Transport In Cylindrical Geometry, Hatem Khouaja, D. Ray Edwards, Nicholas Tsoulfanidis
Spherical Harmonics - Finite Element Treatment Of Neutron Transport In Cylindrical Geometry, Hatem Khouaja, D. Ray Edwards, Nicholas Tsoulfanidis
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
A variational spherical harmonics (DPN) method is used in conjunction with the finite element method to solve the transport of neutron beams. The method is developed for finite axisymmetric cylindrical geometry. In this model, the angular distribution along the path of neutron travel is separated into two sub-ranges of the forward and the backward moving particles. The system of the model equations is cast in terms of an even and an odd vector analogue to the even-parity transport technique. The finite element method is applied in space to solve the resulting coupled system of equations. A source-free cylinder with specified …
Sensor Signal Analysis By Neural Networks For Surveillance In Nuclear Reactors, Shahla Keyvan
Sensor Signal Analysis By Neural Networks For Surveillance In Nuclear Reactors, Shahla Keyvan
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
The application of neural networks as a tool for reactor diagnostics is examined here. Reactor pump signals utilized in a wear-out monitoring system developed for early detection of the degradation of a pump shaft [17] are analyzed as a semi-benchmark test to study the feasibility of neural networks for monitoring and surveillance in nuclear reactors. The Adaptive Resonance Theory (ART 2 and ART 2-A) paradigm of neural networks is applied in this study. The signals are collected signals as well as generated signals simulating the wear progress. The wear-out monitoring system applies noise analysis techniques and is capable of distinguishing …
Optical Filtering Element Including Fluorescent Material, Gary Edward Mueller
Optical Filtering Element Including Fluorescent Material, Gary Edward Mueller
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Optical filtering elements having two opposed surfaces and including at least one thin layer of stable non-reflective fluorescent material provide transparent articles which, when exposed to incident electromagnetic radiation at one surface of the fluorescent layer, absorb certain wavelengths within the fluorescent layer and emit other wavelengths at the opposed surface of the fluorescent layer. In preferred embodiments, when radiation (light) in the visible range (about 400 nm to about 700 nm) is incident on the element from one side, certain wavelengths of radiation which transverse the element are absorbed in the fluorescent layer and other radiation of greater, but …
Optical Filtering Element, Gary Edward Mueller, Timothy D. Ziebarth
Optical Filtering Element, Gary Edward Mueller, Timothy D. Ziebarth
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Optical filtering elements having two opposed surfaces and including at least one thin layer of stable non-reflective fluorescent material provide transparent articles which, when exposed to incident electromagnetic radiation at one surface of the fluorescent layer, absorb certain wavelengths within the fluorescent layer and emit other wavelengths at the opposed surface of the fluorescent layer. In preferred embodiments, when radiation (light) in the visible range (about 400 nm to about 700 nm) is incident on the element from one side, certain wavelengths of radiation which transverse the element are absorbed in the fluorescent layer and other radiation of greater, but …