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1,718 Matching Results

Start Over Year 1994

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(open access)

59. Cold Spring Harbor symposium on quantitative biology: Molecular genetics of cancer

Investigation of the mechanistic aspects of cancer has its roots in the studies on tumor viruses and their effects on cell proliferation, function, and growth. This outstanding progress was well documented in previous Cold Spring Harbor Symposia on Quantitative Biology. In the early to mid 1980s, progress on the development of chromosome mapping strategies and the accumulation of DNA probes that identified polymorphisms, encouraged by the international Human Genome Project, enabled the identification of other genes that contributed to familial inheritance of high susceptibility to specific cancers. This approach was very successful and led to a degree of optimism that one aspect of cancer, the multistep genetic process from early neoplasia to metastatic tumors, was beginning to be understood. It therefore seemed appropriate that the 59th Symposium on Quantitative Biology focus attention on the Molecular Genetics of Cancer. The concept was to combine the exciting progress on the identification of new genetic alterations in human tumor cells with studies on the function of the cancer gene products and how they go awry in tumor cells.

Date: December 31, 1994

Creator: unknown

Object Type: Article

System: The UNT Digital Library

(open access)

A Compton scatter camera for spectral imaging of 0.5 to 3.0 MeV gamma rays

A prototype Compton scatter camera for imaging gamma rays has been built and tested. This camera addresses unique aspects of gamma-ray imaging at nuclear industrial sites, including gamma-ray energies in the 0.5 to 3.0 MeV range and polychromatic fields. Analytic models of camera efficiency, resolution and contaminating events are developed. The response of the camera bears strong similarity to emission computed tomography devices used in nuclear medicine. A direct Fourier based algorithm is developed to reconstruct two-dimensional images of measured gamma-ray fields. Iterative ART and MLE algorithms are also investigated. The point response of the camera to gamma rays of energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms are also investigated. The point response of the camera to gamma rays energies from 0.5 to 2.8 MeV is measured and compared to the analytic models. The direct reconstruction algorithm is at least ten times more efficient than the iterative algorithms and produces images that are, in general, of the same quality. Measured images of several phantoms are shown. Important results include angular resolutions as low as 4.4{degrees}, reproduction of phantom …

Date: December 31, 1994

Creator: Martin, J.B.

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

Computational and experimental studies of hydrodynamic instabilities and turbulent mixing: Review of VNIIEF efforts. Summary report

The report presents the basic results of some calculations, theoretical and experimental efforts in the study of Rayleigh-Taylor, Kelvin-Helmholtz, Richtmyer-Meshkov instabilities and the turbulent mixing which is caused by their evolution. Since the late forties the VNIIEF has been conducting these investigations. This report is based on the data which were published in different times in Russian and foreign journals. The first part of the report deals with calculations an theoretical techniques for the description of hydrodynamic instabilities applied currently, as well as with the results of several individual problems and their comparison with the experiment. These methods can be divided into two types: direct numerical simulation methods and phenomenological methods. The first type includes the regular 2D and 3D gasdynamical techniques as well as the techniques based on small perturbation approximation and on incompressible liquid approximation. The second type comprises the techniques based on various phenomenological turbulence models. The second part of the report describes the experimental methods and cites the experimental results of Rayleigh-Taylor and Richtmyer-Meskov instability studies as well as of turbulent mixing. The applied methods were based on thin-film gaseous models, on jelly models and liquid layer models. The research was done for plane and cylindrical …

Date: December 31, 1994

Creator: Andronov, V. A.; Zhidov, I. G.; Meskov, E. E.; Nevmerzhitskii, N. V.; Nikiforov, V. V.; Razin, A. N. et al.

Object Type: Report

System: The UNT Digital Library

(open access)

Environmental Sciences Division annual progress report for period ending September 30, 1994

This progress report summarizes the research and development activities conducted in the Environmental Sciences Division (ESD) of Oak Ridge National Laboratory during fiscal year (FY) 1994, which extended from October 1, 1993, through September 30, 1994. The report is structured to provide descriptions of current activities and accomplishments in each of the division`s major organizational units. Following the sections describing the organizational units are sections highlighting ESD Scientific, Technical, and Administrative Achievement awards and listing information necessary to covey the scope of the work in the division. An organizational chart of staff and long-term guests who wee in ESD at the end of FY 1994 is located in the final section of the report.

Date: December 31, 1994

Creator: unknown

Object Type: Report

System: The UNT Digital Library

(open access)

Exploration of new perspectives and limitations in Agrobacterium mediated gene transfer technology. Progress report, [June 1, 1992-- May 31, 1994]

This report describes progress aimed at constructing gene-transfer technology for Nicotiana plumbaginifolia. Most actual effort as described herein has so far been directed at exploring new perspectives and limitations in Agrobacterium mediated gene transfer. Accomplishments are described using a core homologous gene targeting vector.

Date: December 31, 1994

Creator: Marton, L.

Object Type: Report

System: The UNT Digital Library

(open access)

Fifth international conference on hyperbolic problems -- theory, numerics, applications: Abstracts

The conference demonstrated that hyperbolic problems and conservation laws play an important role in many areas including industrial applications and the studying of elasto-plastic materials. Among the various topics covered in the conference, the authors mention: the big bang theory, general relativity, critical phenomena, deformation and fracture of solids, shock wave interactions, numerical simulation in three dimensions, the level set method, multidimensional Riemann problem, application of the front tracking in petroleum reservoir simulations, global solution of the Navier-Stokes equations in high dimensions, recent progress in granular flow, and the study of elastic plastic materials. The authors believe that the new ideas, tools, methods, problems, theoretical results, numerical solutions and computational algorithms presented or discussed at the conference will benefit the participants in their current and future research.

Date: December 31, 1994

Creator: unknown

Object Type: Article

System: The UNT Digital Library

(open access)

Geohydrologic data collected from shallow neutron-access boreholes and resultant-preliminary geohydrologic evaluations, Yucca Mountain area, Nye County, Nevada

In cooperation with the US Department of Energy, 74 neutron-access boreholes were drilled in and near the southwestern part of the Nevada Test Site, Nye County, Nevada. Drilling, coring, sample collection and handling, and lithologic and preliminary geohydrologic data are presented in this report. The boreholes were drilled in a combination of alluvium/colluvium, ash-flow tuff, ash-fall tuff, or bedded tuff to depths of 4.6 to 36.6 meters. Air was used as a drilling medium to minimize disturbance of the water content and water potential of drill cuttings, core, and formation rock. Drill cuttings were collected at approximately 0.6-meter intervals. Core was taken at selected intervals from the alluvium/colluvium using drive-coring methods and from tuff using rotary-coring methods. Nonwelded and bedded tuffs were continuously cored using rotary-coring methods. Gravimetric water-content and water-potential values of core generally were greater than those of corresponding drill cuttings. Gravimetric water-content, porosity, and water-potential values of samples generally decreased, and bulk density values increased, as the degree of welding increased. Grain-density values remained fairly constant with changes in the degree of welding. A high degree of spatial variability in water-content and water-potential profiles was noted in closely spaced boreholes that penetrate similar lithologic subunits and was …

Date: December 31, 1994

Creator: Blout, Daniel O.; Hammermeister, Dale P.; Loskot, Carole L. & Chornack, Michael P.

Object Type: Report

System: The UNT Digital Library

(open access)

Geothermal Program Review XII: proceedings. Geothermal Energy and the President's Climate Change Action Plan

Geothermal Program Review XII, sponsored by the Geothermal Division of US Department of Energy, was held April 25--28, 1994, in San Francisco, California. This annual conference is designed to promote effective technology transfer by bringing together DOE-sponsored researchers; utility representatives; geothermal energy developers; suppliers of geothermal goods and services; representatives from federal, state, and local agencies; and others with an interest in geothermal energy. In-depth reviews of the latest technological advancements and research results are presented during the conference with emphasis on those topics considered to have the greatest potential to impact the near-term commercial development of geothermal energy.

Date: December 31, 1994

Creator: unknown

Object Type: Article

System: The UNT Digital Library

(open access)

LLE Review, Quarterly Report: Volume 60, July-September 1994

This volume contains articles on efficient generation of second-harmonic radiation from short-pulse lasers; calculation of the stabilization cutoff wave numbers for the Rayleigh-Taylor instability; a high-frequency silicon optical modulator; the angular dependence of stimulated Brillouin scattering; and femtosecond dynamics of ladder polymers. Three of these articles--second-harmonic generation, Rayleigh-Taylor cutoff wave numbers, and angular dependence of Brillouin scattering--are directly related to the OMEGA Upgrade, currently under construction. A summary of the status of the OMEGA Upgrade laser facility and the NLUF News for FY94 are included in this volume.

Date: December 31, 1994

Creator: Knauer, J. P.

Object Type: Report

System: The UNT Digital Library

(open access)

Managing cumulative impacts: A key to sustainability?

This paper addresses how science can be more effectively used in creating policy to manage cumulative effects on ecosystems. The paper focuses on the scientific techniques that we have to identify and to assess cumulative impacts on ecosystems. The term ``sustainable development`` was brought into common use by the World Commission on Environment and Development (The Brundtland Commission) in 1987. The Brundtland Commission report highlighted the need to simultaneously address developmental and environmental imperatives simultaneously by calling for development that ``meets the needs of the present generation without compromising the needs of future generations.`` We cannot claim to be working toward sustainable development until we can quantitatively assess cumulative impacts on the environment: The two concepts are inextricibally linked in that the elusiveness of cumulative effects likely has the greatest potential of keeping us from achieving sustainability. In this paper, assessment and management frameworks relevant to cumulative impacts are discussed along with recent literature on how to improve such assessments. When possible, examples are given for marine ecosystems.

Date: December 31, 1994

Creator: Hunsaker, C.T.

Object Type: Article

System: The UNT Digital Library

(open access)

Molecular genetics of cancer

This volume contains abstracts of oral and poster presentations made at the LIX Cold Springs Harbor Symposium on Quantitative Biology held June 1--8, 1994.

Date: December 31, 1994

Creator: Stillman, B.

Object Type: Article

System: The UNT Digital Library

(open access)

The oceanic cycle and global atmospheric budget of carbonyl sulfide

A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

Date: December 31, 1994

Creator: Weiss, P.S.

Object Type: Report

System: The UNT Digital Library

(open access)

Originating super-strong liquid crystalline polymers (SSLCPs). Final report

The work at the University of North Carolina at Chapel Hill focused on the experimental characterization of ring mobility in labeled polyaramides with deuterium Nuclear Magnetic Resonance (NMR). Los Alamos National Laboratory prepared the deuterium-labeled analogs of Super-Strong (SS), Liquid Crystalline Polymers (LCPs) and oligomers. These materials were studied to ascertain the influence of substituent size (at the diacid moiety) on the mobility of the labeled diamine. The results are currently being finalized for publication.

Date: December 31, 1994

Creator: unknown

Object Type: Report

System: The UNT Digital Library

(open access)

Processing and properties of iridium alloys for space power applications

Iridium alloys are used as fuel cladding in radioisotope thermoelectric generators due to their high-melting point, high- temperature strength, and oxidation and corrosion resistance. Although iridium has a face-centered cubic crystal structure, it undergoes a distinct ductile-to-brittle transition characteristic of many body-centered cubic metals. Improved ductility in the alloys is achieved through material purification and controlled alloy additions at the parts per million (ppm) level. A vacuum arc remelt operation produces a nearly defect-free casting, which is further processed to sheet products. A change in processing from drop castings of small arc-melted buttons to large arc-remelted ingots has substantially improved product yields. The effects of processing changes on alloy microstructure, sheet textures, oxidation effects, high-strain-rate ductility, and fabricability are discussed.

Date: December 31, 1994

Creator: Ohriner, E. K.

Object Type: Article

System: The UNT Digital Library

$Sensor for measuring the atomic fraction in highly dissociated hydrogen$ (open access)

Sensor for measuring the atomic fraction in highly dissociated hydrogen

Atomic hydrogen is a very important constituent for processes ranging from cleaning oxide from GaAs and annealing amorphous silicon to the deposition of diamond. Because the usual techniques for measuring atomic fraction are either expensive and cumbersome to use, or unsuitable for application to highly dissociated hydrogen, a specially designed sensor was developed. Sensor design is based on a diffusion tube with noncatalytic walls, having one end open to the atom source and a catalytic closure at the other end. The sensor is simple and inexpensive to fabricate, and determining atom density is straightforward. Sensor design also inhibits thermal runaway, which occurs when atom density is high enough to impart enough recombination energy to the non-catalytic surface to substantially raise its temperature. While recombination coefficients for such surfaces are very low near room temperature, they increase nearly exponentially with temperature unless actively cooled. With the use of a straightforward calibration scheme to determine the variation in species fraction along the diffusion tube, the atomic fraction at the tube opening is determined. Design strategy, implementation considerations, and calibration method are presented. In addition, data obtained from an atomic hydrogen source are compared to relevant published data.

Date: December 31, 1994

Creator: Gardner, W.L.

Object Type: Report

System: The UNT Digital Library

(open access)

Uncertainty analysis for low-level radioactive waste disposal performance assessment at Oak Ridge National Laboratory

A performance assessment of the operating Solid Waste Storage Area 6 (SWSA 6) facility for the disposal of low-level radioactive waste at the Oak Ridge National Laboratory has been prepared to provide the technical basis for demonstrating compliance with the performance objectives of DOE Order 5820.2A, Chapter 111.2 An analysis of the uncertainty incorporated into the assessment was performed which addressed the quantitative uncertainty in the data used by the models, the subjective uncertainty associated with the models used for assessing performance of the disposal facility and site, and the uncertainty in the models used for estimating dose and human exposure. The results of the uncertainty analysis were used to interpret results and to formulate conclusions about the performance assessment. This paper discusses the approach taken in analyzing the uncertainty in the performance assessment and the role of uncertainty in performance assessment.

Date: December 31, 1994

Creator: Lee, D. W.; Yambert, M. W. & Kocher, D. C.

Object Type: Article

System: The UNT Digital Library

(open access)

Altus Times (Altus, Okla.), Vol. 94, No. 251, Ed. 1 Friday, December 30, 1994

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.

Date: December 30, 1994

Creator: Lomenick, Rick

Object Type: Newspaper

System: The Gateway to Oklahoma History

(open access)

Summary report of Hanford Site well remediation and decommissioning activities for fiscal year 1994

Remediation and decommissioning of Hanford Site wells has become an integral part of Hanford Site Environmental Restoration (ER) and Resource Conservation and Recovery Act of 1976 (RCRA) groundwater monitoring programs. A well remediation and decommissioning program was funded and implemented in fiscal year (FY) 1993 under the RCRA and Operational Monitoring (ROM) Program. Funding for this work increased in FY 1994. In FY 1994 well decommissioning activities conducted for the ROM program were centered around the 200 West Area; activities for the ER program were centered in the Fitzner/Eberhart Arid Land Ecology (ALE) (Reserve) unit and the Wahluke Slope (North Slope) area. A total of 116 wells and test borings were decommissioned between the two programs during FY 1994. Additionally, five wells were identified as in need of remediation and were successfully brought into compliance with regulatory requirements. As Hanford Site restoration and remediation efforts increase in scope, the well decommissioning program will remain dynamic. The program will aggressively seek to fulfill the needs of the various environmental cleanup and groundwater/vadose monitoring programs. Wells that do not meet regulatory requirements for preservation will continually be identified and remediated or decommissioned accordingly.

Date: December 30, 1994

Creator: Reynolds, K. D.

Object Type: Report

System: The UNT Digital Library