Radioactive Waste Conditioning, Immobilisation, And Encapsulation Processes And Technologies: Overview And Advances (Chapter 7) (open access)

Radioactive Waste Conditioning, Immobilisation, And Encapsulation Processes And Technologies: Overview And Advances (Chapter 7)

The main immobilization technologies that are available commercially and have been demonstrated to be viable are cementation, bituminization, and vitrification. Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either alkali borosilicate glass or alkali aluminophosphate glass. The exact compositions of nuclear waste glasses are tailored for easy preparation and melting, avoidance of glass-in-glass phase separation, avoidance of uncontrolled crystallization, and acceptable chemical durability, e.g., leach resistance. Glass has also been used to stabilize a variety of low level wastes (LLW) and mixed (radioactive and hazardous) low level wastes (MLLW) from other sources such as fuel rod cladding/decladding processes, chemical separations, radioactive sources, radioactive mill tailings, contaminated soils, medical research applications, and other commercial processes. The sources of radioactive waste generation are captured in other chapters in this book regarding the individual practices in various countries (legacy wastes, currently generated wastes, and future waste generation). Future waste generation is primarily driven by interest in sources of clean energy and this has led to an increased interest in advanced nuclear power production. The development of advanced wasteforms is a …
Date: October 19, 2012
Creator: Jantzen, Carol M.; Lee, William E. & Ojovan, Michael I.
System: The UNT Digital Library
Primary Radiation Damage Formation (open access)

Primary Radiation Damage Formation

The physical processes that give rise to changes in the microstructure, and the physical and mechanical properties of materials exposed to energetic particles are initiated by essentially elastic collisions between atoms in what has been called an atomic displacement cascade. The formation and evolution of this primary radiation damage mechanism are described to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the primary variables cascade energy and irradiation temperature are discussed, along with a range of secondary factors that can influence damage formation.
Date: January 1, 2012
Creator: Stoller, Roger E.
System: The UNT Digital Library
Waters, Seas and Wine: Science for Successful Climate Adaptation (open access)

Waters, Seas and Wine: Science for Successful Climate Adaptation

is a growing demand for adaptation science as a vehicle for delivering critical knowledge to public and private organizations that are attempting to adapt to the changing climate. This expansion of adaptation science is occurring, however, in the absence of a robust understanding of how that science can or should contribute to successful adaptation. For the adaptation science enterprise to be successful, it must provide knowledge that has value to adaptation actors. Accomplishing this objective, however, often requires more than just research, and, in fact, may necessitate new cultural perspectives regarding the role of science in public policy as well as new kinds of researchers and research institutions. These issues are explored through a series of case studies from Australia and the United Kingdom that illustrate the various ways in which adaptation science engages with adaptation processes and the extent to which that science can be judged as successful. The case studies demonstrate that there are multiple pathways by which adaptation science can be successful, depending on the knowledge that is needed by a particular actor at a particular stage in the adaptation process. Nevertheless, there are significant opportunities for the more explicit alignment of the needs of decision-makers and …
Date: January 1, 2012
Creator: Preston, Benjamin L
System: The UNT Digital Library
U.S. Patent 8,304,670, Portable Weighing System with Alignment Features (open access)

U.S. Patent 8,304,670, Portable Weighing System with Alignment Features

A system for weighing a load is disclosed. The weighing system includes a pad having at least one transducer for weighing a load disposed on the pad. In some embodiments the pad has a plurality of foot members and the weighing system may include a plate that disposed underneath the pad for receiving the plurality of foot members and for aligning the foot members when the weighing system is installed. The weighing system may include a spacer disposed adjacent the pad and in some embodiments, a spacer anchor operatively secures the spacer to a support surface, such as a plate, a railway bed, or a roadway. In some embodiments the spacer anchor operatively secures both the spacer and the pad to a roadway.
Date: January 1, 2012
Creator: Abercrombie, Robert K; Richardson, Gregory; Scudiere, Matthew B & Sheldon, Frederick T
System: The UNT Digital Library
Data Analysis for Real Time Identification of Grid Disruptions (open access)

Data Analysis for Real Time Identification of Grid Disruptions

The U.S. electric power system comprises multiple distinct interconnections of generators, high voltage transmission systems, and local distribution systems that maintain a continuous balance between generation and load with impressive levels of efficiency and reliability. This critical infrastructure has served the nation remarkably well, but is likely to see more changes over the next decade than it has seen over the past century. In particular, the widespread deployment of renewable generation, smart-grid controls, energy storage, and new conducting materials will require fundamental changes in grid planning and the way we run the power grid. Two challenges in the realization of the smart grid technology are the ability to visualize the deluge of expected data streams for global situational awareness; as well as the ability to detect disruptive and classify such events from spatially-distributed high-speed power system frequency measurements. One element of smart grid technology is the installation of a wide-area frequency measurement system on the electric poles in the streets for conditions monitoring of the distribution lines. This would provide frequency measurements about the status of the electric grid and possible information about impending problems before they start compounding and cascading. The ability to monitor the distribution lines is just …
Date: January 1, 2012
Creator: Chandola, Varun; Omitaomu, Olufemi A & Fernandez, Steven J
System: The UNT Digital Library
X-Ray and Neutron Diffuse Scattering Measurements (open access)

X-Ray and Neutron Diffuse Scattering Measurements

None
Date: January 1, 2012
Creator: Ice, Gene E
System: The UNT Digital Library
Radiation Damage Theory (open access)

Radiation Damage Theory

This chapter presents an overview of basic radiation damage theory, including older and more recent models, to provide framework, within which radiation effects, such as void swelling, can be rationalized. A complete review of the literature is not attempted, but sufficient references are given to provide a decent introduction to a quite large number of publications in the field. Many derivations are different from and, in our view, more elegant than in the original publications. The work is directed to both theoreticians and experimentalists, and, especially, to those passionate individuals who are going to take the radiation damage theory (RDT) to the future.
Date: January 1, 2012
Creator: Golubov, Stanislav I.; Barashev, Aleksandr & Stoller, Roger E.
System: The UNT Digital Library
Correcting transport errors during advection of aerosol and cloud moment sequences in eulerian models (open access)

Correcting transport errors during advection of aerosol and cloud moment sequences in eulerian models

Moment methods are finding increasing usage for simulations of particle population balance in box models and in more complex flows including two-phase flows. These highly efficient methods have nevertheless had little impact to date for multi-moment representation of aerosols and clouds in atmospheric models. There are evidently two reasons for this: First, atmospheric models, especially if the goal is to simulate climate, tend to be extremely complex and take many man-years to develop. Thus there is considerable inertia to the implementation of novel approaches. Second, and more fundamental, the nonlinear transport algorithms designed to reduce numerical diffusion during advection of various species (tracers) from cell to cell, in the typically coarse grid arrays of these models, can and occasionally do fail to preserve correlations between the moments. Other correlated tracers such as isotopic abundances, composition of aerosol mixtures, hydrometeor phase, etc., are subject to this same fate. In the case of moments, this loss of correlation can and occasionally does give rise to unphysical moment sets. When this happens the simulation can come to a halt. Following a brief description and review of moment methods, the goal of this paper is to present two new approaches that both test moment …
Date: March 1, 2012
Creator: R., McGraw
System: The UNT Digital Library
TRITIUM UNCERTAINTY ANALYSIS FOR SURFACE WATER SAMPLES AT THE SAVANNAH RIVER SITE (open access)

TRITIUM UNCERTAINTY ANALYSIS FOR SURFACE WATER SAMPLES AT THE SAVANNAH RIVER SITE

Radiochemical analyses of surface water samples, in the framework of Environmental Monitoring, have associated uncertainties for the radioisotopic results reported. These uncertainty analyses pertain to the tritium results from surface water samples collected at five locations on the Savannah River near the U.S. Department of Energy's Savannah River Site (SRS). Uncertainties can result from the field-sampling routine, can be incurred during transport due to the physical properties of the sample, from equipment limitations, and from the measurement instrumentation used. The uncertainty reported by the SRS in their Annual Site Environmental Report currently considers only the counting uncertainty in the measurements, which is the standard reporting protocol for radioanalytical chemistry results. The focus of this work is to provide an overview of all uncertainty components associated with SRS tritium measurements, estimate the total uncertainty according to ISO 17025, and to propose additional experiments to verify some of the estimated uncertainties. The main uncertainty components discovered and investigated in this paper are tritium absorption or desorption in the sample container, HTO/H{sub 2}O isotopic effect during distillation, pipette volume, and tritium standard uncertainty. The goal is to quantify these uncertainties and to establish a combined uncertainty in order to increase the scientific depth …
Date: July 31, 2012
Creator: Atkinson, R.
System: The UNT Digital Library
DEVELOPMENT AND SELECTION OF IONIC LIQUID ELECTROLYTES FOR HYDROXIDE CONDUCTING POLYBENZIMIDAZOLE MEMBRANES IN ALKALINE FUEL CELLS (open access)

DEVELOPMENT AND SELECTION OF IONIC LIQUID ELECTROLYTES FOR HYDROXIDE CONDUCTING POLYBENZIMIDAZOLE MEMBRANES IN ALKALINE FUEL CELLS

Alkaline fuel cell (AFC) operation is currently limited to specialty applications such as low temperatures and pure H{sub 2}/O{sub 2} due to the corrosive nature of the electrolyte and formation of carbonates. AFCs are the cheapest and potentially most efficient (approaching 70%) fuel cells. The fact that non-Pt catalysts can be used, makes them an ideal low cost alternative for power production. The anode and cathode are separated by and solid electrolyte or alkaline porous media saturated with KOH. However, CO{sub 2} from the atmosphere or fuel feed severely poisons the electrolyte by forming insoluble carbonates. The corrosivity of KOH (electrolyte) limits operating temperatures to no more than 80�C. This chapter examines the development of ionic liquids electrolytes that are less corrosive, have higher operating temperatures, do not chemically bond to CO{sub 2}, and enable alternative fuels. Work is detailed on the IL selection and characterization as well as casting methods within the polybenzimidazole based solid membrane. This approach is novel as it targets the root of the problem (the electrolyte) unlike other current work in alkaline fuel cells which focus on making the fuel cell components more durable.
Date: May 1, 2012
Creator: Fox, E.
System: The UNT Digital Library
Food and drug reward: overlapping circuits in human obesity and addiction (open access)

Food and drug reward: overlapping circuits in human obesity and addiction

Both drug addiction and obesity can be defined as disorders in which the saliency value of one type of reward (drugs and food, respectively) becomes abnormally enhanced relative to, and at the expense of others. This model is consistent with the fact that both drugs and food have powerful reinforcing effects - partly mediated by dopamine increases in the limbic system - that, under certain circumstances or in vulnerable individuals, could overwhelm the brain's homeostatic control mechanisms. Such parallels have generated significant interest in understanding the shared vulnerabilities and trajectories between addiction and obesity. Now, brain imaging discoveries have started to uncover common features between these two conditions and to delineate some of the overlapping brain circuits whose dysfunctions may explain stereotypic and related behavioral deficits in human subjects. These results suggest that both obese and drug addicted individuals suffer from impairments in dopaminergic pathways that regulate neuronal systems associated not only with reward sensitivity and incentive motivation, but also with conditioning (memory/learning), impulse control (behavioral inhibition), stress reactivity and interoceptive awareness. Here, we integrate findings predominantly derived from positron emission tomography that investigate the role of dopamine in drug addiction and in obesity and propose an updated working model …
Date: December 1, 2012
Creator: Volkow, N. D.; Wang, G.; Volkow, N. D.; Wang, G. J.; Fowler, J. S.; Tomasi, D. et al.
System: The UNT Digital Library
Physical and Mechanical Properties of Copper and Copper Alloys (open access)

Physical and Mechanical Properties of Copper and Copper Alloys

High strength, high conductivity copper alloys are prime candidates for high heat flux applications in fusion energy systems. This chapter reviews the physical and mechanical properties of pure copper and copper alloys with the focus on precipitation-hardened CuCrZr and dispersion-strengthened CuAl25 alloys. The effect of neutron irradiation on copper and copper alloys is reviewed in terms of radiation effects on physical properties and mechanical properties (tensile properties, fracture toughness, fatigue and creep-fatigue), irradiation creep and void swelling. The effect of irradiation on the microstructure of copper and copper alloys and dislocation channeling is also presented. Joining techniques for copper alloys in fusion plasma facing components are briefly discussed.
Date: January 1, 2012
Creator: Li, Meimei & Zinkle, Steven J.
System: The UNT Digital Library
Reaction Mechanisms of Pair Transfer (open access)

Reaction Mechanisms of Pair Transfer

None
Date: April 6, 2012
Creator: Thompson, I. J. & Brown, B. A.
System: The UNT Digital Library
Radiation-Induced Effects on Microstructure (open access)

Radiation-Induced Effects on Microstructure

Irradiation of materials with particles that are sufficiently energetic to create atomic displacements can induce significant microstructural alteration, ranging from crystalline-to-amorphous phase transitions to the generation of large concentrations of point defect or solute aggregates in crystalline lattices. These microstructural changes typically cause significant changes in the physical and mechanical properties of the irradiated material. A variety of advanced microstructural characterization tools are available to examine the microstructural changes induced by particle irradiation, including electron microscopy, atom probe field ion microscopy, X-ray scattering and spectrometry, Rutherford backscattering spectrometry, nuclear reaction analysis, and neutron scattering and spectrometry. Numerous reviews, which summarize the microstructural changes in materials associated with electron and heavy ion or neutron irradiation, have been published. These reviews have focused on pure metals as well as model alloys, steels, and ceramic materials. In this chapter, the commonly observed defect cluster morphologies produced by particle irradiation are summarized and an overview is presented on some of the key physical parameters that have a major influence on microstructural evolution of irradiated materials. The relationship between microstructural changes and evolution of physical and mechanical properties is then summarized, with particular emphasis on eight key radiation-induced property degradation phenomena. Typical examples of irradiated …
Date: January 1, 2012
Creator: Zinkle, Steven J.
System: The UNT Digital Library
Scalable Molecular Dynamics with NAMD (open access)

Scalable Molecular Dynamics with NAMD

None
Date: December 14, 2012
Creator: Phillips, J. C.; Schulten, K.; Bhatele, A.; Mei, C.; Sun, Y. & Kale, L. V.
System: The UNT Digital Library
OpenAtom: Ab initio Molecular Dynamics for Petascale Platforms (open access)

OpenAtom: Ab initio Molecular Dynamics for Petascale Platforms

None
Date: December 14, 2012
Creator: Martyna, G. J.; Bohm, E. J.; Venkataraman, R.; Arya, A.; Kale, L. V. & Bhatele, A.
System: The UNT Digital Library
Chapter 10: BlueGene/Q Sequoia and Mira (open access)

Chapter 10: BlueGene/Q Sequoia and Mira

None
Date: April 20, 2012
Creator: Vranas, P.
System: The UNT Digital Library
METALLIC AND HYBRID NANOSTRUCTURES: FUNDAMENTALS AND APPLICATIONS (open access)

METALLIC AND HYBRID NANOSTRUCTURES: FUNDAMENTALS AND APPLICATIONS

This book chapter presents an overview of research conducted in our laboratory on preparation, optical and physico-chemical properties of metallic and nanohybrid materials. Metallic nanoparticles, particularly gold, silver, platinum or a combination of those are the main focus of this review manuscript. These metallic nanoparticles were further functionalized and used as templates for creation of complex and ordered nanomaterials with tailored and tunable structural, optical, catalytic and surface properties. Controlling the surface chemistry on/off metallic nanoparticles allows production of advanced nanoarchitectures. This includes coupled or encapsulated core-shell geometries, nano-peapods, solid or hollow, monometallic/bimetallic, hybrid nanoparticles. Rational assemblies of these nanostructures into one-, two- and tridimensional nano-architectures is described and analyzed. Their sensing, environmental and energy related applications are reviewed.
Date: May 2, 2012
Creator: Murph, S.
System: The UNT Digital Library