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
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
Geologic carbon sequestration as a global strategy to mitigate CO2 emissions: Sustainability and environmental risk (open access)

Geologic carbon sequestration as a global strategy to mitigate CO2 emissions: Sustainability and environmental risk

Fossil fuels are abundant, inexpensive to produce, and are easily converted to usable energy by combustion as demonstrated by mankind's dependence on fossil fuels for over 80% of its primary energy supply (13). This reliance on fossil fuels comes with the cost of carbon dioxide (CO{sub 2}) emissions that exceed the rate at which CO{sub 2} can be absorbed by terrestrial and oceanic systems worldwide resulting in increases in atmospheric CO{sub 2} concentration as recorded by direct measurements over more than five decades (14). Carbon dioxide is the main greenhouse gas linked to global warming and associated climate change, the impacts of which are currently being observed around the world, and projections of which include alarming consequences such as water and food shortages, sea level rise, and social disruptions associated with resource scarcity (15). The current situation of a world that derives the bulk of its energy from fossil fuel in a manner that directly causes climate change equates to an energy-climate crisis. Although governments around the world have only recently begun to consider policies to avoid the direst projections of climate change and its impacts, sustainable approaches to addressing the crisis are available. The common thread of feasible strategies …
Date: April 1, 2011
Creator: Oldenburg, C.M.
System: The UNT Digital Library
A View on Future Building System Modeling and Simulation (open access)

A View on Future Building System Modeling and Simulation

This chapter presents what a future environment for building system modeling and simulation may look like. As buildings continue to require increased performance and better comfort, their energy and control systems are becoming more integrated and complex. We therefore focus in this chapter on the modeling, simulation and analysis of building energy and control systems. Such systems can be classified as heterogeneous systems because they involve multiple domains, such as thermodynamics, fluid dynamics, heat and mass transfer, electrical systems, control systems and communication systems. Also, they typically involve multiple temporal and spatial scales, and their evolution can be described by coupled differential equations, discrete equations and events. Modeling and simulating such systems requires a higher level of abstraction and modularisation to manage the increased complexity compared to what is used in today's building simulation programs. Therefore, the trend towards more integrated building systems is likely to be a driving force for changing the status quo of today's building simulation programs. Thischapter discusses evolving modeling requirements and outlines a path toward a future environment for modeling and simulation of heterogeneous building systems.A range of topics that would require many additional pages of discussion has been omitted. Examples include computational fluid dynamics …
Date: April 1, 2011
Creator: Wetter, Michael
System: The UNT Digital Library
National Library of Medicine Web Resources for Student Health Professionals (open access)

National Library of Medicine Web Resources for Student Health Professionals

Familiarize students affiliated with the Student National Medical Association with the National Library of Medicine's online resources that address medical conditions, health disparities, and public health preparedness needs.
Date: April 2, 2010
Creator: Womble, R.
System: The UNT Digital Library
Hydrogeophysics (open access)

Hydrogeophysics

Developing a predictive understanding of subsurface flow and transport is complicated by the disparity of scales across which controlling hydrological properties and processes span. Conventional techniques for characterizing hydrogeological properties (such as pumping, slug, and flowmeter tests) typically rely on borehole access to the subsurface. Because their spatial extent is commonly limited to the vicinity near the wellbores, these methods often can not provide sufficient information to describe key controls on subsurface flow and transport. The field of hydrogeophysics has evolved in recent years to explore the potential that geophysical methods hold for improving the quantification of subsurface properties and processes relevant for hydrological investigations. This chapter is intended to familiarize hydrogeologists and water resource professionals with the state-of-the-art as well as existing challenges associated with hydrogeophysics. We provide a review of the key components of hydrogeophysical studies, which include: geophysical methods commonly used for shallow subsurface characterization; petrophysical relationships used to link the geophysical properties to hydrological properties and state variables; and estimation or inversion methods used to integrate hydrological and geophysical measurements in a consistent manner. We demonstrate the use of these different geophysical methods, petrophysical relationships, and estimation approaches through several field-scale case studies. Among other applications, …
Date: April 1, 2010
Creator: Hubbard, S. S. & Linde, N.
System: The UNT Digital Library
Experimental Mathematics and Computational Statistics (open access)

Experimental Mathematics and Computational Statistics

The field of statistics has long been noted for techniques to detect patterns and regularities in numerical data. In this article we explore connections between statistics and the emerging field of 'experimental mathematics'. These includes both applications of experimental mathematics in statistics, as well as statistical methods applied to computational mathematics.
Date: April 30, 2009
Creator: Bailey, David H. & Borwein, Jonathan M.
System: The UNT Digital Library
MANHATTAN PROJECT B REACTOR HANFORD WASHINGTON [HANFORD'S HISTORIC B REACTOR (12-PAGE BOOKLET)] (open access)

MANHATTAN PROJECT B REACTOR HANFORD WASHINGTON [HANFORD'S HISTORIC B REACTOR (12-PAGE BOOKLET)]

The Hanford Site began as part of the United States Manhattan Project to research, test and build atomic weapons during World War II. The original 670-square mile Hanford Site, then known as the Hanford Engineer Works, was the last of three top-secret sites constructed in order to produce enriched uranium and plutonium for the world's first nuclear weapons. B Reactor, located about 45 miles northwest of Richland, Washington, is the world's first full-scale nuclear reactor. Not only was B Reactor a first-of-a-kind engineering structure, it was built and fully functional in just 11 months. Eventually, the shoreline of the Columbia River in southeastern Washington State held nine nuclear reactors at the height of Hanford's nuclear defense production during the Cold War era. The B Reactor was shut down in 1968. During the 1980's, the U.S. Department of Energy began removing B Reactor's support facilities. The reactor building, the river pumphouse and the reactor stack are the only facilities that remain. Today, the U.S. Department of Energy (DOE) Richland Operations Office offers escorted public access to B Reactor along a designated tour route. The National Park Service (NPS) is studying preservation and interpretation options for sites associated with the Manhattan Project. …
Date: April 28, 2009
Creator: MS, GERBER
System: The UNT Digital Library
CHAPTER 7. BERYLLIUM ANALYSIS BY NON-PLASMA BASED METHODS (open access)

CHAPTER 7. BERYLLIUM ANALYSIS BY NON-PLASMA BASED METHODS

The most common method of analysis for beryllium is inductively coupled plasma atomic emission spectrometry (ICP-AES). This method, along with inductively coupled plasma mass spectrometry (ICP-MS), is discussed in Chapter 6. However, other methods exist and have been used for different applications. These methods include spectroscopic, chromatographic, colorimetric, and electrochemical. This chapter provides an overview of beryllium analysis methods other than plasma spectrometry (inductively coupled plasma atomic emission spectrometry or mass spectrometry). The basic methods, detection limits and interferences are described. Specific applications from the literature are also presented.
Date: April 20, 2009
Creator: Ekechukwu, A
System: The UNT Digital Library
OVERVIEW OF BERYLLIUM SAMPLING AND ANALYSIS (open access)

OVERVIEW OF BERYLLIUM SAMPLING AND ANALYSIS

Because of its unique properties as a lightweight metal with high tensile strength, beryllium is widely used in applications including cell phones, golf clubs, aerospace, and nuclear weapons. Beryllium is also encountered in industries such as aluminium manufacturing, and in environmental remediation projects. Workplace exposure to beryllium particulates is a growing concern, as exposure to minute quantities of anthropogenic forms of beryllium may lead to sensitization and to chronic beryllium disease, which can be fatal and for which no cure is currently known. Furthermore, there is no known exposure-response relationship with which to establish a 'safe' maximum level of beryllium exposure. As a result, the current trend is toward ever lower occupational exposure limits, which in turn make exposure assessment, both in terms of sampling and analysis, more challenging. The problems are exacerbated by difficulties in sample preparation for refractory forms of beryllium, such as beryllium oxide, and by indications that some beryllium forms may be more toxic than others. This chapter provides an overview of sources and uses of beryllium, health risks, and occupational exposure limits. It also provides a general overview of sampling, analysis, and data evaluation issues that will be explored in greater depth in the remaining …
Date: April 1, 2009
Creator: Brisson, M
System: The UNT Digital Library
Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory (open access)

Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

The last decade witnessed the rapid development and implementation of aberration correction in electron optics, realizing a more-than-70-year-old dream of aberration-free electron microscopy with a spatial resolution below one angstrom [1-9]. With sophisticated aberration correctors, modern electron microscopes now can reveal local structural information unavailable with neutrons and x-rays, such as the local arrangement of atoms, order/disorder, electronic inhomogeneity, bonding states, spin configuration, quantum confinement, and symmetry breaking [10-17]. Aberration correction through multipole-based correctors, as well as the associated improved stability in accelerating voltage, lens supplies, and goniometers in electron microscopes now enables medium-voltage (200-300kV) microscopes to achieve image resolution at or below 0.1nm. Aberration correction not only improves the instrument's spatial resolution but, equally importantly, allows larger objective lens pole-piece gaps to be employed thus realizing the potential of the instrument as a nanoscale property-measurement tool. That is, while retaining high spatial resolution, we can use various sample stages to observe the materials response under various temperature, electric- and magnetic- fields, and atmospheric environments. Such capabilities afford tremendous opportunities to tackle challenging science and technology issues in physics, chemistry, materials science, and biology. The research goal of the electron microscopy group at the Dept. of Condensed Matter Physics and …
Date: April 1, 2008
Creator: Zhu, Y. & Wall, J.
System: The UNT Digital Library
MSTD 2007 Publications and Patents (open access)

MSTD 2007 Publications and Patents

The Materials Science and Technology Division (MSTD) supports the central scientific and technological missions of the Laboratory, and at the same time, executes world-class, fundamental research and novel technological development over a wide range of disciplines. Our organization is driven by the institutional needs in nuclear weapons stockpile science, high-energy-density science, nuclear reactor science, and energy and environment science and technology. We maintain expertise and capabilities in many diverse areas, including actinide science, electron microscopy, laser-materials interactions, materials theory, simulation and modeling, materials synthesis and processing, materials science under extreme conditions, ultrafast materials science, metallurgy, nanoscience and technology, nuclear fuels and energy security, optical materials science, and surface science. MSTD scientists play leadership roles in the scientific community in these key and emerging areas.
Date: April 1, 2008
Creator: King, W. E.
System: The UNT Digital Library
Philosophy of Mind and the Problem of FreeWill in the Light of Quantum Mechanics. (open access)

Philosophy of Mind and the Problem of FreeWill in the Light of Quantum Mechanics.

Arguments pertaining to the mind-brain connection and to the physical effectiveness of our conscious choices have been presented in two recent books, one by John Searle, the other by Jaegwon Kim. These arguments are examined, and it is argued that the difficulties encountered arise from a defective understanding and application of a pertinent part of contemporary science, namely quantum mechanics.
Date: April 1, 2008
Creator: Stapp, Henry & Stapp, Henry P
System: The UNT Digital Library
Biomolecular Modification of Inorganic Crystal Growth (open access)

Biomolecular Modification of Inorganic Crystal Growth

The fascinating shapes and hierarchical designs of biomineralized structures are an inspiration to materials scientists because of the potential they suggest for biomolecular control over materials synthesis. Conversely, the failure to prevent or limit tissue mineralization in the vascular, skeletal, and urinary systems is a common source of disease. Understanding the mechanisms by which organisms direct or limit crystallization has long been a central challenge to the biomineralization community. One prevailing view is that mineral-associated macromolecules are responsible for either inhibiting crystallization or initiating and stabilizing non-equilibrium crystal polymorphs and morphologies through interactions between anionic moieties and cations in solution or at mineralizing surfaces. In particular, biomolecules that present carboxyl groups to the growing crystal have been implicated as primary modulators of growth. Here we review the results from a combination of in situ atomic force microscopy (AFM) and molecular modeling (MM) studies to investigate the effect of specific interactions between carboxylate-rich biomolecules and atomic steps on crystal surfaces during the growth of carbonates, oxalates and phosphates of calcium. Specifically, we how the growth kinetics and morphology depend on the concentration of additives that include citrate, simple amino acids, synthetic Asp-rich polypeptides, and naturally occurring Asp-rich proteins found in both …
Date: April 27, 2007
Creator: De Yoreo, J. J.
System: The UNT Digital Library
Pulsed Power for Solid-State Lasers (open access)

Pulsed Power for Solid-State Lasers

Beginning in the early 1970s, a number of research and development efforts were undertaken at U.S. National Laboratories with a goal of developing high power lasers whose characteristics were suitable for investigating the feasibility of laser-driven fusion. A number of different laser systems were developed and tested at ever larger scale in pursuit of the optimum driver for laser fusion experiments. Each of these systems had associated with it a unique pulsed power option. A considerable amount of original and innovative engineering was carried out in support of these options. Ultimately, the Solid-state Laser approach was selected as the optimum driver for the application. Following this, the Laser Program at the Lawrence Livermore National Laboratory and the University of Rochester undertook aggressive efforts directed at developing the technology. In particular, at Lawrence Livermore National Laboratory, a series of laser systems beginning with the Cyclops laser and culminating in the present with the National Ignition Facility were developed and tested. As a result, a large amount of design information for solid-state laser pulsed power systems has been documented. Some of it is in the form of published papers, but most of it is buried in internal memoranda, engineering reports and LLNL …
Date: April 19, 2007
Creator: Gagnon, W.; Albrecht, G.; Trenholme, J. & Newton, M.
System: The UNT Digital Library
The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces (open access)

The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces

Over the past decade there has been a natural drive to extend the investigation of dynamic surfaces in fluid environments to higher resolution characterization tools. Various aspects of solution crystal growth have been directly visualized for the first time. These include island nucleation and growth using transmission electron microscopy and scanning tunneling microscopy; elemental step motion using scanning probe microscopy; and the time evolution of interfacial atomic structure using various diffraction techniques. In this lecture we will discuss the use of one such in situ method, scanning probe microscopy, as a means of measuring surface dynamics during crystal growth and dissolution. We will cover both practical aspects of imaging such as environmental control, fluid flow, and electrochemical manipulation, as well as the types of physical measurements that can be made. Measurements such as step motion, critical lengths, nucleation density, and step fluctuations, will be put in context of the information they provide about mechanistic processes at surfaces using examples from metal and mineral crystal growth.
Date: April 16, 2007
Creator: Orme, C. A. & Giocondi, J. L.
System: The UNT Digital Library
Macroscopic Modeling of Polymer-Electrolyte Membranes (open access)

Macroscopic Modeling of Polymer-Electrolyte Membranes

In this chapter, the various approaches for the macroscopic modeling of transport phenomena in polymer-electrolyte membranes are discussed. This includes general background and modeling methodologies, as well as exploration of the governing equations and some membrane-related topic of interest.
Date: April 1, 2007
Creator: Weber, A.Z. & Newman, J.
System: The UNT Digital Library
Hydrogen Outgassing from Lithium Hydride (open access)

Hydrogen Outgassing from Lithium Hydride

Lithium hydride is a nuclear material with a great affinity for moisture. As a result of exposure to water vapor during machining, transportation, storage and assembly, a corrosion layer (oxide and/or hydroxide) always forms on the surface of lithium hydride resulting in the release of hydrogen gas. Thermodynamically, lithium hydride, lithium oxide and lithium hydroxide are all stable. However, lithium hydroxides formed near the lithium hydride substrate (interface hydroxide) and near the sample/vacuum interface (surface hydroxide) are much less thermally stable than their bulk counterpart. In a dry environment, the interface/surface hydroxides slowly degenerate over many years/decades at room temperature into lithium oxide, releasing water vapor and ultimately hydrogen gas through reaction of the water vapor with the lithium hydride substrate. This outgassing can potentially cause metal hydriding and/or compatibility issues elsewhere in the device. In this chapter, the morphology and the chemistry of the corrosion layer grown on lithium hydride (and in some cases, its isotopic cousin, lithium deuteride) as a result of exposure to moisture are investigated. The hydrogen outgassing processes associated with the formation and subsequent degeneration of this corrosion layer are described. Experimental techniques to measure the hydrogen outgassing kinetics from lithium hydride and methods employing …
Date: April 20, 2006
Creator: Dinh, L. N.; Schildbach, M. A.; Smith, R. A.; Balazs, B. & McLean, W., II
System: The UNT Digital Library
The CKM quark-mixing matrix (open access)

The CKM quark-mixing matrix

None
Date: April 1, 2006
Creator: Ligeti, Zoltan; Ceccucci, Augusto; Ligeti, Zoltan & Sakai, Yoshihide
System: The UNT Digital Library
Sequencing and comparing whole mitochondrial genomes ofanimals (open access)

Sequencing and comparing whole mitochondrial genomes ofanimals

Comparing complete animal mitochondrial genome sequences is becoming increasingly common for phylogenetic reconstruction and as a model for genome evolution. Not only are they much more informative than shorter sequences of individual genes for inferring evolutionary relatedness, but these data also provide sets of genome-level characters, such as the relative arrangements of genes, that can be especially powerful. We describe here the protocols commonly used for physically isolating mtDNA, for amplifying these by PCR or RCA, for cloning,sequencing, assembly, validation, and gene annotation, and for comparing both sequences and gene arrangements. On several topics, we offer general observations based on our experiences to date with determining and comparing complete mtDNA sequences.
Date: April 22, 2005
Creator: Boore, Jeffrey L.; Macey, J. Robert & Medina, Monica
System: The UNT Digital Library
Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors (open access)

Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful technique for studying bi-molecular interactions at the atomic scale. Our NMR lab is involved in the identification of small molecules, or ligands that bind to target protein receptors, such as tetanus (TeNT) and botulinum (BoNT) neurotoxins, anthrax proteins and HLA-DR10 receptors on non-Hodgkin's lymphoma cancer cells. Once low affinity binders are identified, they can be linked together to produce multidentate synthetic high affinity ligands (SHALs) that have very high specificity for their target protein receptors. An important nanotechnology application for SHALs is their use in the development of robust chemical sensors or biochips for the detection of pathogen proteins in environmental samples or body fluids. Here, we describe a recently developed NMR competition assay based on transferred nuclear Overhauser effect spectroscopy (trNOESY) that enables the identification of sets of ligands that bind to the same site, or a different site, on the surface of TeNT fragment C (TetC) than a known ''marker'' ligand, doxorubicin. Using this assay, we can identify the optimal pairs of ligands to be linked together for creating detection reagents, as well as estimate the relative binding constants for ligands competing for the same site.
Date: April 29, 2004
Creator: Cosman, M; Krishnan, V V & Balhorn, R
System: The UNT Digital Library
Solid Nitrogen at Extreme Conditions of High Pressure and Temperature (open access)

Solid Nitrogen at Extreme Conditions of High Pressure and Temperature

We review the phase diagram of nitrogen in a wide pressure and temperature range. Recent optical and x-ray diffraction studies at pressures up to 300 GPa and temperatures in excess of 1000 K have provided a wealth of information on the transformation of molecular nitrogen to a nonmolecular (polymeric) semiconducting and two new molecular phases. These newly found phases have very large stability (metastability) range. Moreover, two new molecular phases have considerably different orientational order from the previously known phases. In the iota phase (unlike most of other known molecular phases), N{sub 2} molecules are orientationally equivalent. The nitrogen molecules in the theta phase might be associated into larger aggregates, which is in line with theoretical predictions on polyatomic nitrogen.
Date: April 5, 2004
Creator: Goncharov, A. & Gregoryanz, E.
System: The UNT Digital Library
Microscopic Uses of Nanogold. (open access)

Microscopic Uses of Nanogold.

Gold has been used for immunocytochemistry since 1971 when Faulk and Taylor discovered adsorption of antibodies to colloidal gold. It is an ideal label for electron microscopy (EM) due to its high atomic number, which scatters electrons efficiently, and the fact that preparative methods have been developed to make uniform particles in the appropriate size range of 5 to 30 nm. Use in light microscopy (LM) generally requires silver enhancement (autometallography; AMG) of these small gold particles. Significant advances in this field since that time have included a better understanding of the conditions for best antibody adsorption, more regular gold size production, adsorption of other useful molecules, like protein A, and advances in silver enhancement. Many studies have also been accomplished showing the usefulness of these techniques to cell biology and biomedical research. A further advance in this field was the development of Nanogold{trademark}, a 1.4 nm gold cluster. A significant difference from colloidal gold is that Nanogold is actually a coordination compound containing a gold core covalently linked to surface organic groups. These in turn may be covalently attached to antibodies. This approach to immunolabeling has several advantages compared to colloidal gold such as vastly better penetration into tissues, …
Date: April 17, 2003
Creator: Hainfeld, J. F.; Powell, R. D. & Furuya, F. R.
System: The UNT Digital Library
Improving Fan System Performance: A Sourcebook for Industry (open access)

Improving Fan System Performance: A Sourcebook for Industry

This is one of a series of sourcebooks on motor-driven equipment produced by the Industrial Technologies Program. It provides a reference for industrial fan systems users, outlining opportunities to improve fan system performance.
Date: April 1, 2003
Creator: unknown
System: The UNT Digital Library