522 Matching Results

Search Results

Advanced search parameters have been applied.

Further Investigations of Natural Environmental Radiation

Description: Report documenting the investigation of cosmic and terrestrial background radiation. "Remeasurements in many locations furnished estimates of dosimetric increase in terrestrial levels due to fallout. Radiation measurement sin residential dwellings in he New York metropolitan areas are described" (p. 1).
Date: November 3, 1959
Creator: Solon, Leonard R.; Lowder, Wayne M.; Shambon, Arthur & Blatz, Hanson
Partner: UNT Libraries Government Documents Department

The Crosscorrelation Method of Measuring System Dynamic Response

Description: The basic relations of the crosscorrelation method are presented; and variations of the method for dealing with practical cases for which the idealized relations are inaccurate due to finite experiment length, finite bandwidth of the input signal, and uncorrelated noise in the system response signal are discussed and demonstrated. (D.C.W.)
Date: November 1, 1963
Creator: Balcomb, J. D.
Partner: UNT Libraries Government Documents Department

Introduction to naturally occurring radioactive material

Description: Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from ...
Date: August 1, 1997
Creator: Egidi, P.
Partner: UNT Libraries Government Documents Department

Effects of Background Music on Preschoolers' Attention.

Description: Background music is often used in preschool classrooms with the belief that music makes children smarter and increases attention. The purpose of this study was to determine if background music increased children's focused attention during play activities. Focused attention occurs when children maintain attention to a task regardless of distractions. This quasiexperimental study investigated background music and play in a laboratory setting. I videotaped individual children during play with math manipulatives in a pretest-posttest research design with background music used as the treatment. Forty-three 3-, 4-, and 5-year-olds played for 15 minutes. The first 5 minutes of play had no music (pretest), the second 5-minute play episode had background music (treatment), and the final 5-minute play episode had no background music (posttest). Data were analyzed using one-way repeated measures analysis of variance. Findings revealed that the subjects paid less attention to the play task with background music than they did during the pretest, with no music. Another key finding was that children with more musical experiences at home, as reported by the Child's Home Musical Experience Survey (CHIMES), exhibited longer periods of focused attention with background music. This study confirmed previous research that 3-year-old children have shorter focused attention than 4- and 5-year-old children with and without background music. These findings have implications for teachers and parents that background music, instead of increasing attention in children, might indeed decrease children's focused attention during play activities.
Date: December 2009
Creator: Dartt, Kevin Maurine
Partner: UNT Libraries

Background Investigations: Office of Personnel Management Needs to Improve Transparency of Its Pricing and Seek Cost Savings

Description: A letter report issued by the Government Accountability Office with an abstract that begins "OPM’s reported costs to conduct background investigations increased by almost 79 percent, from about $602 million in fiscal year 2005 to almost $1.1 billion in fiscal ear 2011 (in fiscal year 2011 dollars). However, the extent to which OPM’s cost data are reliable is unknown because an audit of OPM’s revolving fund, which finances business-type operations, has not been conducted. Independent audits of OPM’s overall financial management system, where revolving fund transactions are recorded, identified material weaknesses in internal controls, which could affect the reliability of these cost data. OPM’s background investigation program has three principal cost drivers. The first cost driver is investigation fieldwork and support contracts, which represent nearly half of OPM’s fiscal year 2011 reported costs— about $532 million. These contracts allow OPM to assign an investigation to a contractor and buy clerical support for case-management. The second cost driver is personnel compensation and benefits for OPM's background investigation federal workforce, which represents about 25 percent of OPM’s fiscal year 2011 reported costs—about $265 million. The third cost driver is OPM’s information technology investments. While these investments represent less than 10 percent of fiscal year 2011 reported costs, they have increased more than 682 percent over 6 years (in fiscal year 2011 dollars), from about $12 million in fiscal year 2005 to over $91 million in fiscal year 2011. OPM attributed cost increases to more comprehensive subject interviews, increased FBI fees, and compliance with investigation timeliness requirements."
Date: February 28, 2012
Creator: United States. Government Accountability Office.
Partner: UNT Libraries Government Documents Department

Background Investigations: Program Deficiencies May Lead DEA to Relinquish Its Authority to OPM

Description: A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on background investigations conducted by the Drug Enforcement Administration (DEA), focusing on: (1) the circumstances that led DEA to consider relinquishing its authority to conduct personnel background investigations; and (2) whether the Office of Personnel Management (OPM) acted in an independent and objective manner in choosing to review DEA and its background investigations."
Date: September 7, 1999
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department


Description: BS>The theories of the origin of the aurora are discussed from two points of view. The two basic structural types of auroras are described. A discussion is included of radio whistlers. (W.L.H.)
Date: April 1, 1959
Creator: Chamberlain, J.W.
Partner: UNT Libraries Government Documents Department

Fontecilla mix II

Description: Recording of Andrés Lewin Richter's Fontecilla mix II. The piece is a reduction and organization of a 90-minute piece created to be MUZAK type background music -- mainly as climate manipulation rather than a sound poem -- for Chilean painter Ernesto Fontecilla's painting exhibition at Barcelona Galeria Trece in 1977. All material is electronic in origin.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: 1978
Creator: Lewin Richter, Andrés, 1937-
Partner: UNT Music Library

Boltzmann babies in the proper time measure

Description: After commenting briefly on the role of the typicality assumption in science, we advocate a phenomenological approach to the cosmological measure problem. Like any other theory, a measure should be simple, general, well defined, and consistent with observation. This allows us to proceed by elimination. As an example, we consider the proper time cutoff on a geodesic congruence. It predicts that typical observers are quantum fluctuations in the early universe, or Boltzmann babies. We sharpen this well-known youngness problem by taking into account the expansion and open spatial geometry of pocket universes. Moreover, we relate the youngness problem directly to the probability distribution for observables, such as the temperature of the cosmic background radiation. We consider a number of modifications of the proper time measure, but find none that would make it compatible with observation.
Date: December 20, 2007
Creator: Bousso, Raphael; Bousso, Raphael; Freivogel, Ben & Yang, I-Sheng
Partner: UNT Libraries Government Documents Department

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

Description: We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.
Date: November 1, 2013
Creator: Alarcon, Ricardo; Balascuta, S.; Benson, Stephen V.; Bertozzi, William; Boyce, James R.; Cowan, Ray et al.
Partner: UNT Libraries Government Documents Department

Skyshine Contribution to Gamma Ray Background Between 0 and 4 MeV

Description: Natural gamma-ray background is composed of four components; which include cosmic rays, cosmic ray produced atmospheric activity, terrestrial sources, and skyshine from terrestrial sources. Skyshine is radiation scattered from the air above a source that can produce a signal in radiation detection instrumentation. Skyshine has been studied for many years but its contribution to the natural background observed in a detector has not been studied. A large NaI(Tl) detector was used to investigate each of the four components of the natural background using a series of 48-hour measurements and appropriate lead shielding configured to discriminate contributions from each component. It was found that while the contribution from skyshine decreases rapidly with energy, it represents a significant portion of the background spectrum below ~500keV. A similar campaign of measurements using a HPGe detector is underway.
Date: August 14, 2009
Creator: Mitchell, Allison L.; Borgardt, James D. & Kouzes, Richard T.
Partner: UNT Libraries Government Documents Department

Majorana DUSEL R&D Final Report

Description: This report summarizes the work performed at PNNL under the project Majorana Neutrinoless Double Beta Decay DUSEL R&D over the period of FY07-FY09.
Date: September 21, 2010
Creator: Fast, James E.; Hoppe, Eric W.; Mintzer, Esther E.; Aalseth, Craig E.; Day, Anthony R.; Gerlach, David C. et al.
Partner: UNT Libraries Government Documents Department

MADmap: A Massively Parallel Maximum-Likelihood Cosmic Microwave Background Map-Maker

Description: MADmap is a software application used to produce maximum-likelihood images of the sky from time-ordered data which include correlated noise, such as those gathered by Cosmic Microwave Background (CMB) experiments. It works efficiently on platforms ranging from small workstations to the most massively parallel supercomputers. Map-making is a critical step in the analysis of all CMB data sets, and the maximum-likelihood approach is the most accurate and widely applicable algorithm; however, it is a computationally challenging task. This challenge will only increase with the next generation of ground-based, balloon-borne and satellite CMB polarization experiments. The faintness of the B-mode signal that these experiments seek to measure requires them to gather enormous data sets. MADmap is already being run on up to O(1011) time samples, O(108) pixels and O(104) cores, with ongoing work to scale to the next generation of data sets and supercomputers. We describe MADmap's algorithm based around a preconditioned conjugate gradient solver, fast Fourier transforms and sparse matrix operations. We highlight MADmap's ability to address problems typically encountered in the analysis of realistic CMB data sets and describe its application to simulations of the Planck and EBEX experiments. The massively parallel and distributed implementation is detailed and scaling complexities are given for the resources required. MADmap is capable of analysing the largest data sets now being collected on computing resources currently available, and we argue that, given Moore's Law, MADmap will be capable of reducing the most massive projected data sets.
Date: June 9, 2009
Creator: Cantalupo, Christopher; Borrill, Julian; Jaffe, Andrew; Kisner, Theodore & Stompor, Radoslaw
Partner: UNT Libraries Government Documents Department

Higher Education and Entrepreneurship: The Relation between College Educational Background and Small Business Success in Texas

Description: This study examined the relationship between success of small businesses and the educational backgrounds of their owners. A survey composed of questions concerning demographics, educational backgrounds, and business success was mailed to 1100 businesses in Dallas, Denton, and Tarrant counties in Texas. There were 228 usable responses which were analyzed by using the Statistical Package of Social Sciences (SPSS12). Data were sorted so that educational level, sales volume, number of employees, and longevity, were identified on a 5-point ordinal scale. Educational major was identified on a 5-point nominal scale. Pearson's correlation was used to determine whether relationships existed between founders' educational background and small business success. Spearman's correlation was used to determine the direction and strength of the relationships. Then educational level and major were combined with age, gender, ethnicity, and industry, to determine the relationships between founders' educational background, and business success. For this purpose a canonical correlation was used. Five opinion questions concerned influence of college education on business success among college graduates and non-college graduates were identified on a 5-point Likert scale and tested using one-way ANOVA, and independent sample t-test. When educational level and major were the only predictors of business success, a statistically significant relationship was found between years of formal education, and sales volume. When educational level and major were combined with age, gender, ethnicity, and industry, a statistically significant relationship was found between founders' educational level and age, and business success. A statistically significant and negative relationship was found between founders' educational major and industry, and business success. All opinion questions revealed statistically significant relationships between owner's college education and business success. These relationships indicate the ability for the owner to learn, adapt and maintain a successful business. The influence of a college education on small business success was noticeable and reflects the ...
Date: May 2005
Creator: Al-Zubeidi, Mohammad
Partner: UNT Libraries

Background noise spectra of global seismic stations

Description: Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.
Date: August 1, 1996
Creator: Wada, M.M. & Claassen, J.P.
Partner: UNT Libraries Government Documents Department

Limitations on the precision of 238U/235U measurements and implications for environmental monitoring

Description: The ability to determine the isotopic composition of uranium in environmental samples is an important component of the International Atomic Energy Agency`s (IAEA) safeguards program, and variations in the isotopic ratio {sup 238}U/{sup 235}U provide the most direct evidence of isotopic enrichment activities. The interpretation of observed variations in {sup 238}U/{sup 235}U depends on the ability to distinguish enrichment from instrumental biases and any variations occurring in the environment but not related to enrichment activities. Instrumental biases that have historically limited the accuracy of {sup 238}U/{sup 235}U determinations can be eliminated by the use of the {sup 233}U/{sup 236}U double-spike technique. With this technique, it is possible to determine the {sup 238}U/{sup 235}U in samples to an accuracy equal to the precision of the measurement, ca. 0.1% for a few 10`s of nanograms of uranium. Given an accurate determination of {sup 238}U/{sup 235}U, positive identification of enrichment activities depends on the observed value being outside the range of {sup 238}U/{sup 235}U`s expected as a result of natural or environmental variations. Analyses of a suite of soil samples showed no variation beyond 0.2% in {sup 238}U/{sup 235}U.
Date: August 1, 1997
Creator: Russ III, G.P.
Partner: UNT Libraries Government Documents Department

Preliminary noise survey and data report of Saudi Arabian data

Description: From November 1995 to March 1996 a total of 9 broadband temporary stations were deployed across Saudi Arabian shield. These stations consisted of STS-2 seismometers recorded continuously at 40 sps on RefTek dataloggers. All installations were at bedrock sites. Using data sections selected randomly during the deployment, noise studies showed that most stations were exceptionally quiet with noise level near the USGS low noise model for frequencies higher than 0.1 Hz. At lower frequencies, the horizontal components showed increased noise levels, possibly due to instrumental characteristics. High-frequency (greater than 1 Hz) noise varied as much as 10 db between day and night for some stations (RAYN, TAIF) while more isolated stations (HALM) were constant. Seasonal noise levels also varied, with April to June being the quietest months. Slight changes in peak microseism frequency also occurred seasonally.
Date: August 1, 1997
Creator: Mellors, R.
Partner: UNT Libraries Government Documents Department