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Amount, distance-dependent and structural effects of forest patches on bees in agricultural landscapes (open access)

Amount, distance-dependent and structural effects of forest patches on bees in agricultural landscapes

This article is a review examining the effects of forest patches on bees and pollination services to determine how to increase pollination service in agricultural landscapes.
Date: January 21, 2022
Creator: Rahimi, Ehsan; Barghjelveh, Shahindokht & Dong, Pinliang
System: The UNT Digital Library
Automated extraction of attributes from natural language attribute-based access control (ABAC) Policies (open access)

Automated extraction of attributes from natural language attribute-based access control (ABAC) Policies

Article (1) developing a practical framework to extract authorization attributes of hierarchical ABAC system from natural language artifacts, and (2) generating a set of realistic synthetic natural language access control policies (NLACPs) to evaluate the proposed framework.
Date: January 21, 2019
Creator: Alohaly, Manar; Takabi, Hassan & Blanco, Eduardo
System: The UNT Digital Library
Roles and Responsibilities of Cataloging Managers: An Updated Study of Job Advertisements (open access)

Roles and Responsibilities of Cataloging Managers: An Updated Study of Job Advertisements

Article based on a research study to determine employers' current expectations of cataloging managers in academic libraries. A second purpose was to examine how these expectations have changed since 2008. Through deductive thematic content analysis and a univariate approach, researchers identified new trends in cataloging manager job requirements, including additional technology responsibilities and a growing emphasis on diversity and inclusion.
Date: January 21, 2022
Creator: Brannon, Sian; Sassen, Catherine & Yanowski, Kevin
System: The UNT Digital Library
A Constrained Stochastic Weather Generator for Daily Mean Air Temperature and Precipitation (open access)

A Constrained Stochastic Weather Generator for Daily Mean Air Temperature and Precipitation

This article develops and tests a constrained stochastic weather generator (CSWG) for producing daily mean air temperature and precipitation based on annual mean air temperature and precipitation from tree-ring records. It presents a unique method that can be used to explore historic (e.g., archeological questions) or future (e.g., climate change) daily weather conditions based upon specified annual values.
Date: January 21, 2021
Creator: Pan, Feifei; Nagaoka, Lisa; Wolverton, Steven J.; Atkinson, Samuel F.; Kohler, Timothy A. & O'Neill, Marty
System: The UNT Digital Library
Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible? (open access)

Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible?

Article explores the question of whether animals with switched phenotypes during early development are unable to return to a normal range of adult phenotypes, or whether they do not experience the specific environmental conditions necessary for them to switch back to the normal range of adult phenotypes.
Date: January 21, 2020
Creator: Burggren, Warren W.
System: The UNT Digital Library
The spectrum of two interesting stochastic matrices (open access)

The spectrum of two interesting stochastic matrices

Article discusses the determination of the spectrum of two interesting stochastic matrices appearing in an engineering paper.
Date: January 21, 2020
Creator: Anghel, Nicolae
System: The UNT Digital Library
Current Status of AMOEBA–IL: A Multipolar/Polarizable Force Field for Ionic Liquids (open access)

Current Status of AMOEBA–IL: A Multipolar/Polarizable Force Field for Ionic Liquids

Paper reviews the development and application of the multipolar and polarizable force field AMOEBA for ionic liquid systems, termed AMOEBA–IL.
Date: January 21, 2020
Creator: Vázquez-Montelongo, Erik Antonio; Vázquez-Cervantes, José Enrique & Cisneros, Gerardo Andrés
System: The UNT Digital Library
Fundamentals of wetting and bonding between ceramics and metals (open access)

Fundamentals of wetting and bonding between ceramics and metals

The conditions and the reactions that lead to the realization of chemical equilibrium at interfaces and thus to chemical bonding is discussed with specific attention to the platinum/glass and gold/glass systems. Wetting of the solid by the liquid and formation of an interface are part of the problem. Sessile drop experiments and their interpretation are included. 10 figs, 12 refs. (GHT)
Date: January 21, 1977
Creator: Pask, J. A.
System: The UNT Digital Library
Near-infrared Adaptive Optics Imaging of the Satellites and Individual Rings of Uranus from the W.M. Keck Observatory (open access)

Near-infrared Adaptive Optics Imaging of the Satellites and Individual Rings of Uranus from the W.M. Keck Observatory

None
Date: January 21, 2004
Creator: Gibbard, S G; de Pater, I & Hammel, H B
System: The UNT Digital Library
An Integrated Universal Collapsar Gamma-ray Burst Model (open access)

An Integrated Universal Collapsar Gamma-ray Burst Model

Starting with two assumptions: (1) gamma-ray bursts originate from stellar death phenomena or so called ''collapsars'' and (2) that these bursts are quasi-universal, whereby the majority of the observed variation is due to our perspective of the jet, an integrated gamma-ray burst model is proposed. It is found that several of the key correlations in the data can be naturally explained with this simple picture and another possible correlation is predicted.
Date: January 21, 2004
Creator: Salmonson, J D
System: The UNT Digital Library
Feature Subset Selection, Class Separability, and Genetic Algorithms (open access)

Feature Subset Selection, Class Separability, and Genetic Algorithms

The performance of classification algorithms in machine learning is affected by the features used to describe the labeled examples presented to the inducers. Therefore, the problem of feature subset selection has received considerable attention. Genetic approaches to this problem usually follow the wrapper approach: treat the inducer as a black box that is used to evaluate candidate feature subsets. The evaluations might take a considerable time and the traditional approach might be unpractical for large data sets. This paper describes a hybrid of a simple genetic algorithm and a method based on class separability applied to the selection of feature subsets for classification problems. The proposed hybrid was compared against each of its components and two other feature selection wrappers that are used widely. The objective of this paper is to determine if the proposed hybrid presents advantages over the other methods in terms of accuracy or speed in this problem. The experiments used a Naive Bayes classifier and public-domain and artificial data sets. The experiments suggest that the hybrid usually finds compact feature subsets that give the most accurate results, while beating the execution time of the other wrappers.
Date: January 21, 2004
Creator: Cantu-Paz, E
System: The UNT Digital Library
Open Midplane Dipole Design for Lhc Ir Upgrade. (open access)

Open Midplane Dipole Design for Lhc Ir Upgrade.

The proposed luminosity upgrade of the Large Hadron Collider (LHC), now under construction, will bring a large increase in the number of secondary particles from p-p collisions at the interaction point (IP). Energy deposition will be so large that the lifetime and quench performance of interaction region (IR) magnets may be significantly reduced if conventional designs are used. Moreover, the cryogenic capacity of the LHC will have to be significantly increased as the energy deposition load on the interaction region (IR) magnets by itself will exhaust the present capacity. We propose an alternate open midplane dipole design concept for the dipole-first optics that mitigates these issues. The proposed design takes advantage of the fact that most of the energy is deposited in the midplane region. The coil midplane region is kept free of superconductor, support structure and other material. Initial energy deposition calculations show that the increase in temperature remains within the quench tolerance of the superconducting coils. In addition, most of the energy is deposited in a relatively warm region where the heat removal is economical. We present the basic concept and preliminary design that includes several innovations.
Date: January 21, 2004
Creator: Gupta, R.; Anerella, M.; Harrison, M.; Schmalzle, J. & Mokhov, N.
System: The UNT Digital Library
The Development of a Detailed Chemical Kinetic Mechanism for Diisobutylene and Comparison to Shock Tube Ignition Times (open access)

The Development of a Detailed Chemical Kinetic Mechanism for Diisobutylene and Comparison to Shock Tube Ignition Times

There is much demand for chemical kinetic models to represent practical fuels such as gasoline, diesel and aviation fuel. These blended fuels contain hundreds of components whose identity and amounts are often unknown. A chemical kinetic mechanism that would represent the oxidation of all these species with accompanying chemical reactions is intractable with current computational capabilities, chemical knowledge and manpower resources. The use of surrogate fuels is an approach to make the development of chemical kinetic mechanisms for practical fuels tractable. A surrogate fuel model consists of a small number of fuel components that can be used to represent the practical fuel and still predict desired characteristics of the practical fuel. These desired fuel characteristics may include ignition behavior, burning velocity, fuel viscosity, fuel vaporization, and fuel emissions (carbon monoxide, hydrocarbons, soot and nitric oxides). Gasoline consists of many different classes of hydrocarbons including n-alkanes, alkenes, iso-alkanes, cycloalkanes, cycloalkenes, and aromatics. One approach is to use a fuel surrogate that has a single component from each class of hydrocarbon in gasoline so that the unique molecular structure of each class is represented. This approach may lead to reliable predictions of many of the combustion properties of the practical fuel. In …
Date: January 21, 2005
Creator: Metcalfe, W; Curran, H J; Simmie, J M; Pitz, W J & Westbrook, C K
System: The UNT Digital Library
Playing With Sandpiles. (open access)

Playing With Sandpiles.

The Bak-Tang-Wiesenfeld sandpile model provides a simple and elegant system with which to demonstrate self-organized criticality. This model has rather remarkable mathematical properties first elucidated by Dhar. I demonstrate some of these properties graphically with a simple computer simulation.
Date: January 21, 2003
Creator: Creutz, M.
System: The UNT Digital Library
Permanent Magnet Designs With Large Variations in Field Strength. (open access)

Permanent Magnet Designs With Large Variations in Field Strength.

The use of permanent magnets has been investigated as an option for electron cooling ring for the proposed luminosity upgrade of RHIC. Several methods have been developed that allow a large variation in field strength. These design concepts were verified with computer simulations using finite element codes. It will be shown that the field uniformity is maintained while the field strength is mechanically adjusted.
Date: January 21, 2004
Creator: Gupta, R.
System: The UNT Digital Library
Cryogenic loading of large volume presses for high-pressure experimentation and synthesis of novel materials (open access)

Cryogenic loading of large volume presses for high-pressure experimentation and synthesis of novel materials

We present an efficient easily implemented method for loading cryogenic fluids in a large volume press. We specifically apply this method to the high-pressure synthesis of an extended solid derived from CO using a Paris-Edinburgh cell. This method employs cryogenic cooling of Bridgman type WC anvils well insulated from other press components, condensation of the load gas within a brass annulus surrounding the gasket between the Bridgman anvils. We demonstrate the viability of the described approach by synthesizing macroscopic amounts (several milligrams) of polymeric CO-derived material, which were recovered to ambient conditions after compression of pure CO to 5 GPa or above.
Date: January 21, 2005
Creator: Lipp, M. J.; Evans, W. J. & Yoo, C. S.
System: The UNT Digital Library
Near-conservative behavior of 129Iodine in the Orange County Aquifer System, California (open access)

Near-conservative behavior of 129Iodine in the Orange County Aquifer System, California

Iodine is a biophilic element, with one stable isotope, {sup 127}I, and one long-lived radioisotope, {sup 129}I, which originates in the surface environment almost entirely from anthropogenic activities such as nuclear fuel reprocessing. Very few studies have evaluated the geochemical behavior of iodine isotopes in the subsurface. The concentrations of {sup 129}I and {sup 127}I were measured in wells fed by a series of artificial recharge ponds in the Forebay Area of the Orange County groundwater basin (California, USA) to evaluate their potential use as hydrological tracers. To substantiate interpretation of {sup 129}I and {sup 127}I concentration data, the aquifer system was evaluated using literature values of aquifer water mass age based on {sup 3}H/{sup 3}He, Xenon and {delta}{sup 18}O tracer data, as well as time-series data of Santa Ana River flow rates over the past decade. The aquifer data demonstrate the nearly conservative behavior of {sup 129}I, with {sup 129}I/{sup 127}I ratios likely reflecting variations in source functions as well as climatic conditions, and with inferred particle-water partition coefficients (K{sub d}) of 0.1 cm{sup 3} g{sup -1} or less.
Date: January 21, 2005
Creator: Schwer, K. A.; Santschi, P H; Moran, J. E. & Elmore, D.
System: The UNT Digital Library
A Component Architecture for High-Performance Computing (open access)

A Component Architecture for High-Performance Computing

The Common Component Architecture (CCA) provides a means for developers to manage the complexity of large-scale scientific software systems and to move toward a ''plug and play'' environment for high-performance computing. The CCA model allows for a direct connection between components within the same process to maintain performance on inter-component calls. It is neutral with respect to parallelism, allowing components to use whatever means they desire to communicate within their parallel ''cohort.'' We will discuss in detail the importance of performance in the design of the CCA and will analyze the performance costs associated with features of the CCA.
Date: January 21, 2003
Creator: Bernholdt, D E; Elwasif, W R; Kohl, J A & Epperly, T G W
System: The UNT Digital Library
Borehole induction logging for the Dynamic Underground Stripping Project LLNL gasoline spill site (open access)

Borehole induction logging for the Dynamic Underground Stripping Project LLNL gasoline spill site

Borehole induction logs were acquired for the purpose of characterizing subsurface physical properties and monitoring steam clean up activities at the Lawrence Livermore National Laboratory. This work was part of the Dynamic Underground Stripping Project`s demonstrated clean up of a gasoline spin. The site is composed of unconsolidated days, sands and gravels which contain gasoline both above and below the water table. Induction logs were used to characterize lithology, to provide ``ground truth`` resistivity values for electrical resistance tomography (ERT), and to monitor the movement of an underground steam plume used to heat the soil and drive volatile organic compounds (VOCs) to the extraction wells.
Date: January 21, 1994
Creator: Boyd, S.; Newmark, R. & Wilt, M.
System: The UNT Digital Library
Carbon dioxide cleaning pilot project (open access)

Carbon dioxide cleaning pilot project

In 1989, radioactive-contaminated metal at the Rocky Flats Plant (RFP) was cleaned using a solvent paint stripper (Methylene chloride). One-third of the radioactive material was able to be recycled; two-thirds went to the scrap pile as low-level mixed waste. In addition, waste solvent solutions also required disposal. Not only was this an inefficient process, it was later prohibited by the Resource Conservation and Recovery Act (RCRA), 40 CFR 268. A better way of doing business was needed. In the search for a solution to this situation, it was decided to study the advantages of using a new technology - pelletized carbon dioxide cleaning. A proof of principle demonstration occurred in December 1990 to test whether such a system could clean radioactive-contaminated metal. The proof of principle demonstration was expanded in June 1992 with a pilot project. The purpose of the pilot project was three fold: (1) to clean metal so that it can satisfy free release criteria for residual radioactive contamination at the Rocky Flats Plant (RFP); (2) to compare two different carbon dioxide cleaning systems; and (3) to determine the cost-effectiveness of decontamination process in a production situation and compare the cost of shipping the metal off site for …
Date: January 21, 1994
Creator: Knight, L. & Blackman, T. E.
System: The UNT Digital Library
Kinetic theory of radiation effects (open access)

Kinetic theory of radiation effects

To help achieve the quantitative and mechanistic understanding of these processes, the kinetic theory of radiation effects has been developed in the DOE basic energy sciences radiation effects and fusion reactor materials programs, as well as in corresponding efforts in other countries. This discipline grapples with a very wide range of phenomena and draws on numerous sub-fields of theory such as defect physics, diffusion, elasticity, chemical reaction rates, phase transformations and thermodynamics. The theory is cast in a mathematical framework of continuum dynamics. Issues particularly relevant to the present inquiry can be viewed from the standpoints of applications of the theory and areas requiring further progress.
Date: January 21, 1987
Creator: Mansur, L.K.
System: The UNT Digital Library
Fabrication and evaluation of transmissive multilayer optics for 8 keV x rays (open access)

Fabrication and evaluation of transmissive multilayer optics for 8 keV x rays

We have made and tested several sliced multilayer structures which can function as transmissive x-ray optical elements (diffraction gratings, zone plates, and phase gratings) at 8 keV. Our automated multilayer sputtering system is optimized to sputter layers of arbitrary thickness for very large total deposits at high deposition rates. Diffraction patterns produced by the multilayer devices closely match theoretical predictions. Such transmissive optics have the potential for wide application in high resolution microscope and spectrometer systems. 13 refs., 10 figs.
Date: January 21, 1988
Creator: Bionta, R. M.; Jankowski, Alan Frederic & Makowiecki, D. M.
System: The UNT Digital Library
General CP properties of neutrino mass eigenstates (open access)

General CP properties of neutrino mass eigenstates

We show that the mass eigenvectors of the neutrino mass matrix have definite CP quantum numbers whether or not CP is conserved, and we examine the conditions under which a mixture of even and odd CP eigenstates will occur.
Date: January 21, 1984
Creator: Rosen, S. P.
System: The UNT Digital Library
Radioactive Threat Detection with Scattering Physics: A Model-Based Application (open access)

Radioactive Threat Detection with Scattering Physics: A Model-Based Application

The detection of radioactive contraband is a critical problem in maintaining national security for any country. Emissions from threat materials challenge both detection and measurement technologies especially when concealed by various types of shielding complicating the transport physics significantly. The development of a model-based sequential Bayesian processor that captures both the underlying transport physics including scattering offers a physics-based approach to attack this challenging problem. It is shown that this processor can be used to develop an effective detection technique.
Date: January 21, 2010
Creator: Candy, J V; Chambers, D H; Breitfeller, E F; Guidry, B L; Verbeke, J M; Axelrod, M A et al.
System: The UNT Digital Library