Application and performance of remote bioventing systems powered by wind

International Nuclear Information System (INIS)

Graves, D.; Hague, K.; Wilson, B.; Dillon, T. Jr.; Klein, J.; McLaughlin, J.; Olson, G.

1995-01-01

Wind-powered bioventing systems were designed to operate at remote locations in the absence of electrical power. Laboratory measurements of soil respiration under bioventing conditions indicated the biodegradation of up to 25 mg of weathered diesel per kg of site soil per day. Further testing demonstrated the potential for harnessing wind-power to stimulate air movement through vadose zone soil. A 12-in. attic turbine in a 10-mph wind was found to generate 0.025 in. of water vacuum with an airflow of approximately 2.5 ft 3 per min. Two wind-powered bioventing systems were installed near Nome, Alaska. In situ respiration tests and soil gas composition measurements indicated that the systems were capable of aerating the soil. Measurements of diesel-range organics (DRO) taken during installation and at the end of the treatment season show concentration reductions of 29 and 87% at the two sites

Soil moisture effects during bioventing in fuel-contaminated arid soils

International Nuclear Information System (INIS)

Zwick, T.C.; Leeson, A.; Hinchee, R.E.; Hoeppel, R.E.; Bowling, L.

1995-01-01

This study evaluated the effects of soil moisture addition on microbial activity during bioventing of dry, sandy soils at the Marine Corps Air Ground Combat Center (MCAGCC), Twentynine Palms, California. Soils at the site have been contaminated to a depth of approximately 80 ft (24 m) with gasoline, JP-5 jet fuel, and diesel fuel. Based on the low soil moisture measured at the site (2 to 3% by weight), it was determined that soil moisture may be limiting biodegradation. To evaluate the effect that moisture addition had on microbial activity under field conditions, a subsurface drip irrigation system was installed above the fuel hydrocarbon plume. Irrigation water was obtained from two monitoring wells on the site, where groundwater was approximately 192 ft (59 m) below ground surface. Advancement of the wetting front was monitored. In situ respiration rates increased significantly after moisture addition. The results of this study provide evidence for the potential applicability of moisture addition in conjunction with bioventing for site remediation in arid environments. Further work is planned to investigate optimization of moisture addition

Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

International Nuclear Information System (INIS)

Marshall, T.R.

1995-01-01

Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

Bioventing feasibility test to aid remediation strategy

CSIR Research Space (South Africa)

Pearce, K

1998-01-01

Full Text Available A case study is presented where the feasibility of bioventing was assessed for the remediation of a petroleum-contaminated site. This was achieved through the determination of the radius of influence of a single vent well, the soil gas permeability...

Natural bioventing remediation from tidal wave action at a field site

International Nuclear Information System (INIS)

Kampbell, D.H.; Kittel, J.A.

1996-01-01

A remediation research study has been implemented at a jet fuel spill site on an island airport. A buried pipeline fracture several years ago resulted in a fuel spill exceeding 160,000 gallons. The site hydrogeology is a fragmented coral matrix with fresh water overlying more dense salt water. Water table fluctuations of about two feet occur once every twelve hours from tidal action. The research approach being pursued is to recover free-phase floating petroleum liquid using vacuum-mediated subsurface skimming wells. The vacuum will create an active vadose zone aeration to enhance aerobic biodegradation processes and vaporization of fuel. Once the floating fuel is removed, a natural bioventing action caused by tidal oscillations will complete remediation of the spill site

Benzene, toluene and p-xylene interactions and the role of microbial communities in remediation using bioventing

Energy Technology Data Exchange (ETDEWEB)

Sui, H. [Tianjin Univ., Tianjin (China). School of Chemical Engineering and Technology; Tianjin Univ., Tianjin (China). National Engineering Research Center for Distillation Technology; Li, X.G.; Jiang, B. [Tianjin Univ., Tianjin (China). National Engineering Research Center for Distillation Technology

2005-04-01

Bioventing is a promising in-situ soil remediation technology used to clean soils and groundwater contaminated by aromatic hydrocarbon components benzene, toluene and xylene (BTX). These contaminants are present at numerous hazardous waste sites. Bioventing provides enough oxygen to stimulate aerobic biodegradation by indigenous microorganisms. It is not constrained by contaminant volatility and can therefore be applied to contaminants that are readily biodegradable even if they are not highly volatile. This study examined the volatilization and biodegradation of BTX during bioventing from unsaturated soil. It focused on the occurrence of any substrate interaction and the effects of indigenous microbial inocula. The soil was inoculated with indigenous microorganisms obtained from the Dagang Oil Field in Tianjin, China. Then, different amounts of BTX were added to the soil in a stainless steel column through which carbon dioxide free air and pure nitrogen flowed. The volatilization-to-biodegradation ratios of BTX were 6:1, 2:1 and 2:1 respectively. After 3 weeks, the final concentration in the soil gas was 0.128 mg/L benzene, 0.377 mg/L toluene and 0.143 mg/L xylene. The substrate interactions that occurred were as follows: benzene and xylene degradation was accelerated while toluene was being degraded; and, the presence of xylene increased the lag period for benzene degradation. It was concluded that bioventing is an effective remediation technology for aromatic hydrocarbons and can significantly reduce the remediation time if target residual BTX concentration of 0.1 mg/L is to be reached. BTX removal becomes more significant with time, particularly when soils are inoculated with indigenous microbial communities from contaminated soil. 22 refs., 5 tabs., 7 figs.

Remedial Action Plan for Expanded Bioventing System Facility 6454

National Research Council Canada - National Science Library

1996-01-01

This draft remedial action plan (RAP) presents the scope for an expanded bioventing system for in situ treatment of fuel-contaminated soils at Site 6454 at Vandenberg Air Force Base (AFB), California...

Installation of a bio-venting remediation system using directionally drilled horizontal wells

International Nuclear Information System (INIS)

Hardy, L.; Stolz, A.P.

1997-01-01

The installation of a remediation system for off-site contamination was discussed. The site was contaminated with gasoline and diesel from an abandoned bulk fuel storage and distribution terminal located near a highway. The dissolved phase hydrocarbon plume extended beneath several houses down gradient of the site. Bioventing was considered to be the only remediation option to recover the liquid phase hydrocarbons beneath the highway in a way that would satisfy all the clean-up objectives and the design constraints. Bioventing is closely related to soil vapour extraction (SVE). The main difference is that in bioventing, the mechanism for removal of contaminants is bio-degradation by indigenous bacteria, whereas in SVE, contaminants are simply removed by volatilization. Bioventing systems enhance the activity of the indigenous bacteria by inducing air flow in the subsurface through the use of vapour injection or extraction wells. Two horizontal vapour extraction wells were installed with a directional drill. A soil pile was utilized as a bio-filter for the extracted hydrocarbon vapours and a backfilled trench was used to inject vapours recovered from the soil pile to the subsurface. The total mass of hydrocarbons degraded by this system in 230 days was estimated to be 1,000 kg. It was concluded that under appropriate conditions the in-situ treatment of contaminated soil using directionally drilled wells can be justified on both economic and technical grounds. 3 refs., 1 tab., 5 figs

Bioventing - a new twist on soil vapor remediation of the vadose zone and shallow ground water

International Nuclear Information System (INIS)

Yancheski, T.B.; McFarland, M.A.

1992-01-01

Bioventing, which is a combination of soil vapor remediation and bioremediation techniques, may be an innovative, cost-effective, and efficient remedial technology for addressing petroleum contamination in the vadose zone and shallow ground water. The objective of bioventing is to mobilize petroleum compounds from the soil and ground water into soil vapor using soil vapor extraction and injection technology, and to promote the migration of the soil vapor upward to the turf root zone for degradation by active near-surface microbiological activity. Promoting and maintaining optimum microbiological activity in the turf root rhizosphere is a key component to the bioventing technique. Preliminary ongoing USEPA bioventing pilot studies (Kampbell, 1991) have indicated that this technique is a promising remediation technology, although feasibility studies are not yet complete. However, based on the preliminary data, it appears that proper bioventing design and implementation will result in substantial reductions of petroleum compounds in the capillary zone and shallow ground water, complete degradation of petroleum compounds in the turf root zone, and no surface emissions. A bioventing system was installed at a site in southern Delaware with multiple leaking underground storage tanks in early 1992 to remediate vadose zone and shallow ground-water contaminated by petroleum compounds. The system consists of a series of soil vapor extraction and soil vapor/atmospheric air injection points placed in various contamination areas and a central core remediation area (a large grassy plot). This system was chosen for this site because it was least costly to implement and operate as compared to other remedial alternatives (soil vapor extraction with carbon or catalytic oxidation of off-gas treatment, insitu bioremediation, etc.), and results in the generation of no additional wastes

Soil Vapor Extraction and Bioventing Test Work Plan for the MOGAS Site, Myrtle Beach Air Force Base, South Carolina

National Research Council Canada - National Science Library

1995-01-01

This work plan presents an evaluation of soil vapor extraction (SVE) and bioventing, and describes the SVE pilot scale and bioventing activities to be conducted to extract and treat soil gas at Installation Restoration Program (IRP...

MICHIGAN SOIL VAPOR EXTRACTION REMEDIATION (MISER) MODEL: A COMPUTER PROGRAM TO MODEL SOIL VAPORT EXTRACTION AND BIOVENTING OF ORGANIC MATERIALS IN UNSATURATED GEOLOGICAL MATERIAL

Science.gov (United States)

This report describes the formulation, numerical development, and use of a multiphase, multicomponent, biodegradation model designed to simulate physical, chemical, and biological interactions occurring primarily in field scale soil vapor extraction (SVE) and bioventing (B...

MICHIGAN SOIL VAPOR EXTRACTION REMEDIATION (MISER) MODEL: A COMPUTER PROGRAM TO MODEL SOIL VAPOR EXTRACTION AND BIOVENTING OF ORGANIC CHEMICALS IN UNSATURATED GEOLOGICAL MATERIAL

Science.gov (United States)

Soil vapor extraction (SVE) and bioventing (BV) are proven strategies for remediation of unsaturated zone soils. Mathematical models are powerful tools that can be used to integrate and quantify the interaction of physical, chemical, and biological processes occurring in field sc...

Interim Measures Work Plan Expanded Bioventing System SWMU 55 (IRP Site FT-03)

National Research Council Canada - National Science Library

1997-01-01

This interim measures work plan (IMWP) presents the scope for an expanded bioventing system to conduct in situ treatment of the remaining fuel-contaminated soils at solid waste management unit (SWMU...

Operations and Maintenance Manual for Expanded Bioventing System Site FC-2 Kelly AFB, Texas

National Research Council Canada - National Science Library

1996-01-01

This Operations and Maintenance Manual has been created as a guide for monitoring and maintaining the performance of the bioventing blower and vent well plumbing at the Fire Training Area (Site FC-2...

Pilot-scale studies of soil vapor extraction and bioventing for remediation of a gasoline spill at Cameron Station, Alexandria, Virginia

Energy Technology Data Exchange (ETDEWEB)

Harrison, W.; Joss, C.J.; Martino, L.E. [and others

1994-07-01

Approximately 10,000 gal of spilled gasoline and unknown amounts Of trichloroethylene and benzene were discovered at the US Army`s Cameron Station facility. Because the base is to be closed and turned over to the city of Alexandria in 1995, the Army sought the most rapid and cost-effective means of spill remediation. At the request of the Baltimore District of the US Army Corps of Engineers, Argonne conducted a pilot-scale study to determine the feasibility of vapor extraction and bioventing for resolving remediation problems and to critique a private firm`s vapor-extraction design. Argonne staff, working with academic and private-sector participants, designed and implemented a new systems approach to sampling, analysis and risk assessment. The US Geological Survey`s AIRFLOW model was adapted for the study to simulate the performance of possible remediation designs. A commercial vapor-extraction machine was used to remove nearly 500 gal of gasoline from Argonne-installed horizontal wells. By incorporating numerous design comments from the Argonne project team, field personnel improved the system`s performance. Argonne staff also determined that bioventing stimulated indigenous bacteria to bioremediate the gasoline spin. The Corps of Engineers will use Argonne`s pilot-study approach to evaluate remediation systems at field operation sites in several states.

Bioventing feasibility study of low permeability soils for remediation of petroleum contamination

International Nuclear Information System (INIS)

Brackney, K.M.

1994-01-01

A site characterization of leaking underground gasoline and diesel storage tanks at the University of Idaho, West Farm Operations Center, identified approximately 800 cubic yards of petroleum-contaminated soil exceedingly regulatory action limits of 100 ppm TPH. Bioventing, a combination of in situ soil vapor extraction and microbial degradation, was selected as a remedial alternative on the basis of the presumably unsaturated paleo-soil with a 45-foot depth to groundwater, and a microbial study which concluded that indigenous petroleum-degrading microorganisms existed throughout the contamination. Soil vapor extraction tests were conducted by applying a 60-inch water column vacuum to a soil vapor extraction well and monitoring pneumatic pressure drawdown in 12 adjacent pneumatic piezometers and vertically distributed piezometer clusters. Pressure drawdown vs time data plots indicated that air permeability is inadequate everywhere at the site except at 20 feet below ground surface. Low soil permeability creates conditions for a perched water table that was documented during the investigation, resulting in unsatisfactory conditions for in situ bioventing. 8 refs., 14 figs

Remedial Action Plan for Expanded Bioventing System Buildings 2034/2035, Fairchild Air Force Base, Washington

National Research Council Canada - National Science Library

1996-01-01

This remedial action plan (RAP) presents the scope for an expanded bioventing system for in situ treatment of fuel-contaminated soils in the vicinity of Buildings 2034 and 2035 at Fairchild Air Force Base (AFB), Washington...

Corrective Action Plan for Expanded Bioventing System Site FT-03, Charleston Air Force Base, South Carolina

National Research Council Canada - National Science Library

1996-01-01

.... The primary objectives of the bioventing system upgrade are to: ̂ Deliver oxygen to additional areas of the site that have subsurface soils contaminated with fuel hydrocarbons that did not receive...

Evaluación de las técnicas de atenuación natural, bioventing, bioaumentación y bioaumentación- bioventing, para la biodegradación de diésel en un suelo arenoso, en experimentos en columna

Directory of Open Access Journals (Sweden)

Angélica María Muskus Morales

2013-08-01

Full Text Available El presente estudio fue desarrollado dentro del convenio de cooperación institucional realizado entre laUniversidad Pontifi cia Bolivariana, Seccional Bucaramanga y el Instituto Colombiano de Petróleos – ICP, con el fi nde dar solución a una problemática que se presenta en las zonas de manejo de hidrocarburos, donde se evidenciansuelos arenosos contaminados con diésel hasta concentraciones del 6% y a una profundidad máxima de 80 cm.Para el desarrollo metodológico se contaminó un suelo artifi cialmente con diésel para evaluar las técnicas deBioventing, Atenuación Natural, Bioaumentación y Bioventing-Bioaumentación, utilizando montajes en columnas.Se defi nieron los parámetros de diseño y seguimiento como dimensiones de las columnas, caudal de entrada,concentración de diésel, oxígeno disuelto y crecimiento bacteriano; para la bioaumentación se inoculó el suelocon un consorcio bacteriano producido por el ICP. Se realizaron los montajes experimentales por triplicado y secontroló el proceso durante cuatro meses. Los resultados obtenidos mostraron que en la técnica de Bioventingse obtuvieron porcentajes de remoción de diésel hasta del 97%. Con la técnica de Bioventing-Bioaumentación sealcanzaron porcentajes de remoción hasta del 75% y con las técnicas de Atenuación Natural y Bioaumentación,los porcentajes de remoción no superaron el 48%. El estudio mostró que el consorcio bacteriano utilizado yevaluado mediante las técnicas de Bioaumentación y Bioventing-Bioaumentación, no potencializó la efi cienciade los procesos de biorremediación del suelo arenoso contaminado con diésel.

Corrective Action Plan for Expanded Bioventing System Site FT-03, Charleston Air Force Base, South Carolina

National Research Council Canada - National Science Library

1996-01-01

... (former Fire Protection Training Area No. 3), Charleston Air Force Base (AFB), South Carolina. A one-year bioventing pilot study previously conducted at this site had successful results in reducing fuel hydrocarbons in soils...

Cold climate bioventing with soil warming in Alaska

International Nuclear Information System (INIS)

Sayles, G.D.; Brenner, R.C.; Leeson, A.; Hinchee, R.E.; Vogel, C.M.

1995-01-01

In the heart of Alaska, a 3-year field study was conducted of bioventing in conjunction with several soil warming methods. The contamination was JP-4 jet fuel. The soil warming methods evaluated, chosen for their apparent low cost, were (1) application of warm water at a low rate, (2) enhanced solar warming by covering the surface with clear plastic in the summer and covering the surface with insulation in the winter, and (3) buried heat pipe. The warm water and buried heat tape methods performed best, maintaining summer-like 10 to 20 C temperatures in the test plots year round, compared to the temperature of the unheated control plot, which dipped to -1 C in the winter. The solar/insulation warming method showed a modest improvement in temperature over the unheated control test plot. The annual average temperatures of the warm water, heat tape, solar, and control plots were 16.9, 14.5, 6.1, and 3.5 C, respectively. The biodegradation rates, measured by in situ respirometry, were higher in plots with higher temperatures and followed the Arrhenius relationship. Despite the low temperature, significant biodegradation was observed in the unheated plot during the winter

The effect of temperature on the bioventing of soil contaminated with toluene and decane

NARCIS (Netherlands)

Malina, G.; Grotenhuis, J.T.C.; Rulkens, W.H.

1999-01-01

The effect of temperature on evaporation and biodegradation rates during soil bioventing (SBV) was studied for a mixture of toluene and decane in bench-scale soil columns at a continuous air flow and consecutively at two different flow rates. The effect of temperature on SBV was monitored by GC

BIODEGRADATION OF DIESEL OIL IN SOIL AND ITS ENHANCEMENT BY APPLICATION OF BIOVENTING AND AMENDMENT WITH BREWERY WASTE EFFLUENTS AS BIOSTIMULATION-BIOAUGMENTATION AGENTS

Directory of Open Access Journals (Sweden)

Samuel Agarry

2015-02-01

Full Text Available The purpose of this study is to investigate and evaluate the effects of natural bioattenuation, bioventing, and brewery waste effluents amendment as biostimulation-bioaugmentation agent on biodegradation of diesel oil in unsaturated soil. A microcosm system was constructed consisting of five plastic buckets containing 1 kg of soil, artificially contaminated or spiked with 10% w/w of diesel oil. Biodegradation was monitored over 28 days by determining the total petroleum hydrocarbon content of the soil and total hydrocarbon degrading bacteria. The results showed that combination of brewery waste effluents amendment and bioventing technique was the most effective, reaching up to 91.5% of diesel removal from contaminated soil; with the brewery waste effluents amendment (biostimulation-bioaugmentation, the percentage of diesel oil removal was 78.7%; with bioventing, diesel oil percentage degradation was 61.7% and the natural bioattenuation technique resulted in diesel oil removal percentage be not higher than 40%. Also, the total hydrocarbon-degrading bacteria (THDB count in all the treatments increased throughout the remediation period. The highest bacterial growth was observed for combined brewery waste effluents amendment with bioventing treatment strategy. A first-order kinetic model was fitted to the biodegradation data to evaluate the biodegradation rate and the corresponding half-life time was estimated. The model revealed that diesel oil contaminated-soil microcosms under combined brewery waste effluents amendment with bioventing treatment strategy had higher biodegradation rate constants, k as well as lower half-life times, t1/2 than other remediation systems. This study showed that the microbial consortium, organic solids, nitrogen and phosphorus present in the brewery waste effluents proved to be efficient as potential biostimulation-bioaugmentation agents for bioremediation processes of soils contaminated with diesel oil

Vapor Extraction/Bioventing Sequential Treatment of Soil Contaminated with Volatile and SemiVolatile Hydrocarbon Mixtures

NARCIS (Netherlands)

Malina, G.; Grotenhuis, J.T.C.; Rulkens, W.H.

2002-01-01

A cost-effective removal strategy was studied in bench-scale columns that involved vapor extraction and bioventing sequential treatment of toluene- and decane-contaminated soil. The effect of operating mode on treatment performance was examined at a continuous air flow and consecutively at two

Interim Corrective Measures Work Plan for the Expanded Bioventing System Eglin Main Base Old Fire Training Area

National Research Council Canada - National Science Library

1997-01-01

This interim corrective measures work plan (ICM work plan) presents the scope for an expanded bioventing system for in situ treatment of fuel-contaminated soils at the Eglin Main Base Old Fire Training Area (old Eglin FTA...

Final technology report for D-Area oil seepage basin bioventing optimization test, environmental restoration support

International Nuclear Information System (INIS)

Radway, J.C.; Lombard, K.H.; Hazen, T.C.

1997-01-01

One method proposed for the cleanup of the D-Area Oil Seepage Basin was in situ bioremediation (bioventing), involving the introduction of air and gaseous nutrients to stimulate contaminant degradation by naturally occurring microorganisms. To test the feasibility of this approach, a bioventing system was installed at the site for use in optimization testing by the Environmental Biotechnology Section of the Savannah River Technology Center. During the interim action, two horizontal wells for a bioventing remediation system were installed eight feet below average basin grade. Nine piezometers were also installed. In September of 1996, a generator, regenerative blower, gas cylinder station, and associated piping and nutrient injection equipment were installed at the site and testing was begun. After baseline characterization of microbial activity and contaminant degradation at the site was completed, four injection campaigns were carried out. These consisted of (1) air alone, (2) air plus triethylphosphate (TEP), (3) air plus nitrous oxide, and (4) air plus methane. This report describes results of these tests, together with conclusions and recommendations for further remediation of the site. Natural biodegradation rates are high. Oxygen, carbon dioxide, and methane levels in soil gas indicate substantial levels of baseline microbial activity. Oxygen is used by indigenous microbes for biodegradation of organics via respiration and hence is depleted in the soil gas and water from areas with high contamination. Carbon dioxide is elevated in contaminated areas. High concentrations of methane, which is produced by microbes via fermentation once the oxygen has been depleted, are found at the most contaminated areas of this site. Groundwater measurements also indicated that substantial levels of natural contaminant biodegradation occurred prior to air injection

Enhanced biodegradation of hydrocarbons in-situ via bioventing

International Nuclear Information System (INIS)

Newman, B.; Martinson, M.; Smith, G.; McCain, L.

1993-01-01

This case study discusses the remediation of soils beneath a former service station impacted with volatile and semi-volatile petroleum compounds. Subsurface investigation revealed hydrocarbon contamination representative of weathered gasoline and diesel fuel in a stratified soil profile consisting of sand and silts. Only unsaturated soils were contaminated with no impact to ground water. A bioventing corrective action approach was selected which included excavation of 6,100 cubic yards of impacted soils with soil mixing to add inorganic nutrients and eliminate soil heterogeneities. Soils were then returned to the excavation after forced-air ventilation lateral lines were installed at the floor of the excavation. Soil vapor concentrations of benzene, toluene, ethylbenzene, xylenes (BTEX) rapidly declined within the first three months of system operation to nondetectable levels

Operations and Maintenance Manual for Full-Scale Bioventing System at FSA-1, Air Force Plant 4, Fort Worth, Texas

National Research Council Canada - National Science Library

1996-01-01

This Operations and Maintenance (O&M) Manual has been created as a guide for monitoring and maintaining the performance of the full-scale bioventing blower system and vent well plumbing at FSA-1 at Air Force Plant 4 (AFP4), Texas...

Respiration testing for bioventing and biosparging remediation of petroleum contaminated soil and ground water

International Nuclear Information System (INIS)

Gray, A.L.; Brown, A.; Moore, B.J.; Payne, R.E.

1996-01-01

Respiration tests were performed to measure the effect of subsurface aeration on the biodegradation rates of petroleum hydrocarbon contamination in vadose zone soils (bioventing) and ground water (biosparging). The aerobic biodegradation of petroleum contamination is typically limited by the absence of oxygen in the soil and ground water. Therefore, the goal of these bioremediation technologies is to increase the oxygen concentration in the subsurface and thereby enhance the natural aerobic biodegradation of the organic contamination. One case study for biosparging bioremediation testing is presented. At this site atmospheric air was injected into the ground water to increase the dissolved oxygen concentration in the ground water surrounding a well, and to aerate the smear zone above the ground water table. Aeration flow rates of 3 to 8 cfm (0.09 to 0.23 m 3 /min) were sufficient to increase the dissolved oxygen concentration. Petroleum hydrocarbon biodegradation rates of 32 to 47 microg/l/hour were calculated based on measurements of dissolved oxygen concentration in ground water. The results of this test have demonstrated that biosparging enhances the biodegradation of petroleum hydrocarbons, but the results as they apply to remediation are not known. Two case studies for bioventing respiration testing are presented

Final Bioventing Pilot Test Work Plan for Base Exchange Service Station Underground Storage Tank Area, Vandenberg Air Force Base, California. Part I

National Research Council Canada - National Science Library

1992-01-01

This pilot test work plan presents the scope of an in situ enhanced biological degradation, or "bioventing", pilot test for treatment of gasoline- contaminated soils at the Base Exchange Service Station (BXSS...

Monitoring biodegradation of diesel fuel in bioventing processes using in situ respiration rate.

Science.gov (United States)

Lee, T H; Byun, I G; Kim, Y O; Hwang, I S; Park, T J

2006-01-01

An in situ measuring system of respiration rate was applied for monitoring biodegradation of diesel fuel in a bioventing process for bioremediation of diesel contaminated soil. Two laboratory-scale soil columns were packed with 5 kg of soil that was artificially contaminated by diesel fuel as final TPH (total petroleum hydrocarbon) concentration of 8,000 mg/kg soil. Nutrient was added to make a relative concentration of C:N:P = 100:10:1. One soil column was operated with continuous venting mode, and the other one with intermittent (6 h venting/6 h rest) venting mode. On-line O2 and CO2 gas measuring system was applied to measure O2 utilisation and CO2 production during biodegradation of diesel for 5 months. Biodegradation rate of TPH was calculated from respiration rate measured by the on-line gas measuring system. There were no apparent differences between calculated biodegradation rates from two columns with different venting modes. The variation of biodegradation rates corresponded well with trend of the remaining TPH concentrations comparing other biodegradation indicators, such as C17/pristane and C18/phytane ratio, dehydrogenase activity, and the ratio of hydrocarbon utilising bacteria to total heterotrophic bacteria. These results suggested that the on-line measuring system of respiration rate would be applied to monitoring biodegradation rate and to determine the potential applicability of bioventing process for bioremediation of oil contaminated soil.

Electrokinetic enhanced bioventing of gasoline in clayey soil: A case history

International Nuclear Information System (INIS)

Loo, W.W.; Wang, I.S.; Fan, J.

1994-01-01

This paper presents a case history on the bioventing of gasoline in soil with electrokinetic enhancement. The gasoline in soil was related to a 10,000-gallon underground storage tank spill, San Diego, California. The gasoline soil plume covers an area of about 2,400 square feet and to a depth of about 30 feet. The upper 15 feet of the soil plume consists of highly conductive marine clay. The lower 15 feet of the soil plume consists of dense cemented conglomerate sandstone. The gasoline concentration in the soil plume range from 100 to 2,200 mg/Kg(ppm) and the target cleanup level is below 100 ppm. Total gasoline in soil plume is estimated at about 1,000 pounds of gasoline in about 3,500 tons of soil. The soil remediation effort was completed after about 90 days of treatment. The concentration of gasoline in soil after treatment was way below the proposed cleanup level of less than 100 mg/Kg(ppm). The cost of treatment is about $50 per ton for this advanced soil treatment process which provides a cost effective solution to this soil plume with minimum disruption to business operation at the facility

Demonstrating practical application of soil and groundwater clean-up and recovery technologies at natural gas processing facilities: Bioventing, air sparging and wetlands remediation

International Nuclear Information System (INIS)

Moore, B.

1996-01-01

This issue of the project newsletter described the nature of bioventing, air sparging and wetland remediation. It reviewed their effectiveness in remediating hydrocarbon contaminated soil above the groundwater surface. Bioventing was described as an effective, low cost treatment in which air is pumped below ground to stimulate indigenous bacteria. The bacteria then use the oxygen to consume the hydrocarbons, converting them to CO 2 and water. Air sparging involves the injection of air below the groundwater surface. As the air rises, hydrocarbons are stripped from the contaminated soil and water. The advantage of air sparging is that it cleans contaminated soil and water from below the groundwater surface. Hydrocarbon contamination of wetlands was described as fairly common. Conventional remediation methods of excavation, trenching, and bellholes to remove contamination often cause extreme harm to the ecosystem. Recent experimental evidence suggests that wetlands may be capable of attenuating contaminated water through natural processes. Four hydrocarbon contaminated wetlands in Alberta are currently under study. Results to date show that peat's high organic content promotes sorption and biodegradation and that some crude oil spills can been resolved by natural processes. It was suggested that assuming peat is present, a good clean-up approach may be to contain the contaminant source, monitor the lateral and vertical extent of contamination, and wait for natural processes to resolve the problem. 3 figs

PART I: Bioventing Pilot Test Work Plan for Fire Protection Training Area Site FY-03, Charleston AFB, South Carolina. PART II: Draft Interim Pilot Test Results Report for Fire Protection Training Area Site FT-03, Charleston AFB, South Carolina

National Research Council Canada - National Science Library

1993-01-01

This site-specific work plan presents the scope of a bioventing pilot test for in situ treatment of fuel contaminated soils at the Fire Protection Training Area designated as Site FT-O3, Charleston Air Force Base (AFB), South Carolina...

Report on bioventing of petroleum contaminated soils at 108-3C: Active extraction and passive injection (barometric pumping) of a gaseous nutrient

International Nuclear Information System (INIS)

Kastner, J.R.; Lombard, K.; Radway, J.

1997-01-01

A bioventing system was constructed with horizontal extraction wells and vertical injection wells in an area which had previously been excavated and then backfilled. Initial in-situ respiration rates (air addition only) suggest that hydrocarbon degradation may be nutrient limited. The rate of TPH degradation was maximum (0.8-1.2 mg/kg/day) between 10-15 ft (bgs), but dropped to essentially zero 30 ft (bgs) within the contaminated zone (even though previous analysis at this depth indicated a TPH concentration of 3800 ppm). Analysis of the soil at 17 ft showed that NO 3 and PO 4 were below detection limits (0.5 ppm), indicating that nutrient limitation may be occurring. Nitrate levels were highest at 10 ft (bgs), correlating with the highest respiration rates. However, phosphate levels were at/or below detection levels throughout tile site (indicating possible PO 4 limitation). Viable cells increased from 3 x 10 6 cfu/g at 3 ft (bgs) to 1 x 10 7 cfu/g at 10 ft (bgs) and remained relatively constant down to 17 ft. Cell numbers in the control area were significantly lower than in the contaminated zone (4.5 x 10 3 ). Gas phase nutrients (triethlyphosphate and nitrous oxide) will be injected to see if the hydrocarbon degradation rate can be increased

The Swarm Initial Field Model for the 2014 Geomagnetic Field

Science.gov (United States)

Olsen, Nils; Hulot, Gauthier; Lesur, Vincent; Finlay, Christopher C.; Beggan, Ciaran; Chulliat, Arnaud; Sabaka, Terence J.; Floberghagen, Rune; Friis-Christensen, Eigil; Haagmans, Roger

2015-01-01

Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites, explicit advantage is taken of the constellation aspect by including east-west magnetic intensity gradient information from the lower satellite pair. Along-track differences in magnetic intensity provide further information concerning the north-south gradient. The SIFM static field shows excellent agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for east-west intensity differences between the lower satellite pair being only 0.12 nT.

Entropy for the Quantized Field in the Atom-Field Interaction: Initial Thermal Distribution

Directory of Open Access Journals (Sweden)

Luis Amilca Andrade-Morales

2016-09-01

Full Text Available We study the entropy of a quantized field in interaction with a two-level atom (in a pure state when the field is initially in a mixture of two number states. We then generalise the result for a thermal state; i.e., an (infinite statistical mixture of number states. We show that for some specific interaction times, the atom passes its purity to the field and therefore the field entropy decreases from its initial value.

The Swarm Initial Field Model for the 2014 geomagnetic field

DEFF Research Database (Denmark)

Olsen, Nils; Hulot, Gauthier; Lesur, Vincent

2015-01-01

agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for East...

Initial singularity and pure geometric field theories

Science.gov (United States)

Wanas, M. I.; Kamal, Mona M.; Dabash, Tahia F.

2018-01-01

In the present article we use a modified version of the geodesic equation, together with a modified version of the Raychaudhuri equation, to study initial singularities. These modified equations are used to account for the effect of the spin-torsion interaction on the existence of initial singularities in cosmological models. Such models are the results of solutions of the field equations of a class of field theories termed pure geometric. The geometric structure used in this study is an absolute parallelism structure satisfying the cosmological principle. It is shown that the existence of initial singularities is subject to some mathematical (geometric) conditions. The scheme suggested for this study can be easily generalized.

Inhomogeneous initial data and small-field inflation

Science.gov (United States)

Marsh, M. C. David; Barrow, John D.; Ganguly, Chandrima

2018-05-01

We consider the robustness of small-field inflation in the presence of scalar field inhomogeneities. Previous numerical work has shown that if the scalar potential is flat only over a narrow interval, such as in commonly considered inflection-point models, even small-amplitude inhomogeneities present at the would-be onset of inflation at τ = τi can disrupt the accelerated expansion. In this paper, we parametrise and evolve the inhomogeneities from an earlier time τIC at which the initial data were imprinted, and show that for a broad range of inflationary and pre-inflationary models, inflection-point inflation withstands initial inhomogeneities. We consider three classes of perturbative pre-inflationary solutions (corresponding to energetic domination by the scalar field kinetic term, a relativistic fluid, and isotropic negative curvature), and two classes of exact solutions to Einstein's equations with large inhomogeneities (corresponding to a stiff fluid with cylindrical symmetry, and anisotropic negative curvature). We derive a stability condition that depends on the Hubble scales H(τi) and H(τIC), and a few properties of the pre-inflationary cosmology. For initial data imprinted at the Planck scale, the absence of an inhomogeneous initial data problem for inflection-point inflation leads to a novel, lower limit on the tensor-to-scalar ratio.

Halo shapes, initial shear field, and cosmic web

International Nuclear Information System (INIS)

Rossi, G

2014-01-01

The ellipsoidal collapse model, combined with the excursion set theory, allows one to estimate the shapes of dark matter halos as seen in high-resolution numerical simulations. The same theoretical framework predicts a quasi-universal behaviour for the conditional axis ratio distributions at later times, set by initial conditions and unaltered by non-linear evolution. The formalism for halo shapes is also useful in making the connection with the initial shear field of the cosmic web, which plays a crucial role in the formation of large-scale structures. The author has briefly discussed the basic aspects of the modelling, as well as the implications of a new formula for the constrained eigenvalues of the initial shear field, given the fact that positions are peaks or dips in the corresponding density field – and not random locations. This formula leads to a new generalized excursion set algorithm for peaks in Gaussian random fields. The results highlighted, here, are relevant for a number of applications, especially for weak lensing studies and for devising algorithms to find and classify structures in the cosmic web

An iterative reconstruction of cosmological initial density fields

Science.gov (United States)

Hada, Ryuichiro; Eisenstein, Daniel J.

2018-05-01

We present an iterative method to reconstruct the linear-theory initial conditions from the late-time cosmological matter density field, with the intent of improving the recovery of the cosmic distance scale from the baryon acoustic oscillations (BAOs). We present tests using the dark matter density field in both real and redshift space generated from an N-body simulation. In redshift space at z = 0.5, we find that the reconstructed displacement field using our iterative method are more than 80% correlated with the true displacement field of the dark matter particles on scales k < 0.10h Mpc-1. Furthermore, we show that the two-point correlation function of our reconstructed density field matches that of the initial density field substantially better, especially on small scales (<40h-1 Mpc). Our redshift-space results are improved if we use an anisotropic smoothing so as to account for the reduced small-scale information along the line of sight in redshift space.

In-situ active/passive bioreclamation of vadose zone soils contaminated with gasoline and waste oil using soil vapor extraction/bioventing: Laboratory pilot study to full scale site operation

International Nuclear Information System (INIS)

Zachary, S.P.; Everett, L.G.

1993-01-01

The use of soil venting to supply oxygen and remove metabolites from the biodegradation of light hydrocarbons is a cost effective in-situ remediation approach. To date, little data exists on the effective in-situ bioreclamation of vadose zone soil contaminated with waste/hydraulic oil without excavation or the addition of water or nutrients to degrade the heavy petroleum contaminants. Gasoline and waste/hydraulic oil contaminated soils below an active commercial building required an in-situ non-disruptive remediation approach. Initial soil vapor samples collected from the vadose zone revealed CO 2 concentrations in excess of 16% and O 2 concentrations of less than 1% by volume. Soil samples were collected from below the building within the contaminated vadose zone for laboratory chemical and physical analysis as well as to conduct a laboratory biotreatability study. The laboratory biotreatability study was conducted for 30 days to simulate vadose zone bioventing conditions using soil taken from the contaminated vadose zone. Results of the biotreatability study revealed that the waste oil concentrations had been reduced from 960 mg/Kg to non-detectable concentrations within 30 days and the volatile hydrocarbon content had decreased exponentially to less than 0.1% of the original concentration. Post treatability study biological enumeration revealed an increase in the microbial population of two orders of magnitude

Initial time singularities and admissible initial states for a system of coupled scalar fields

Energy Technology Data Exchange (ETDEWEB)

Baacke, Juergen [Technische Univ. Dortmund (Germany). Fakultaet Physik; Kevlishvili, Nina [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); GAS, Tbilisi (Georgia). Andronikashvili Inst. of Physics

2009-10-15

We discuss the problem of initial states for a system of coupled scalar fields out of equilibrium in the one-loop approximation. The fields consist of classical background fields, taken constant in space, and quantum fluctuations. If the initial state is the adiabatic vacuum, i.e., the ground state of a Fock space of particle excitations that diagonalize the mass matrix, the energy-momentum tensor is infinite at t=0, its most singular part behaves as 1/t. When the system is coupled to gravity this presents a problem that we solve by a Bogoliubov transformation of the naive initial state. As a side result we also discuss the canonical formalism and the adiabatic particle number for such a system. Most of the formalism is presented for Minkowksi space. Embedding the system and its dynamics into a flat FRW universe is straightforward and we briefly address the essential modifications. (orig.)

Initial time singularities and admissible initial states for a system of coupled scalar fields

International Nuclear Information System (INIS)

Baacke, Juergen; Kevlishvili, Nina; GAS, Tbilisi

2009-10-01

We discuss the problem of initial states for a system of coupled scalar fields out of equilibrium in the one-loop approximation. The fields consist of classical background fields, taken constant in space, and quantum fluctuations. If the initial state is the adiabatic vacuum, i.e., the ground state of a Fock space of particle excitations that diagonalize the mass matrix, the energy-momentum tensor is infinite at t=0, its most singular part behaves as 1/t. When the system is coupled to gravity this presents a problem that we solve by a Bogoliubov transformation of the naive initial state. As a side result we also discuss the canonical formalism and the adiabatic particle number for such a system. Most of the formalism is presented for Minkowksi space. Embedding the system and its dynamics into a flat FRW universe is straightforward and we briefly address the essential modifications. (orig.)

APPLICATION, PERFORMANCE, AND COSTS OF ...

Science.gov (United States)

A critical review of biological treatment processes for remediation of contaminated soils is presented. The focus of the review is on documented cost and performance of biological treatment technologies demonstrated at full- or field-scale. Some of the data were generated by the U.S. Environmental Protection Agency's (EPA's) Bioremediation in the Field Program, jointly supported by EPA's Office of Research and Development, EPA's Office of Solid Waste and Emergency Waste, and the EPA Regions through the Superfund Innovative Technology Evaluation Program (SITE) Program. Military sites proved to be another fertile data source. Technologies reviewed in this report include both ex-situ processes, (land treatment, biopile/biocell treatment, composting, and bioslurry reactor treatment) and in-situ alternatives (conventional bioventing, enhanced or cometabolic bioventing, anaerobic bioventing, bioslurping, phytoremediation, and natural attenuation). Targeted soil contaminants at the documented sites were primarily organic chemicals, including BTEX, petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), chlorinated aliphatic hydrocarbons (CAHs), organic solvents, polychlorinated biphenyls (PCBs), pesticides, dioxin, and energetics. The advantages, limitations, and major cost drivers for each technology are discussed. Box and whisker plots are used to summarize before and after concentrations of important contaminant groups for those technologies consider

Phase 1 remediation of jet fuel contaminated soil and groundwater at JFK International Airport using dual phase extraction and bioventing

International Nuclear Information System (INIS)

Roth, R.; Bianco, P. Rizzo, M.

1995-01-01

Soil and groundwater contaminated with jet fuel at Terminal One of the JFK International Airport in New York have been remediated using dual phase extraction (DPE) and bioventing. Two areas were remediated using 51 DPE wells and 20 air sparging/air injection wells. The total area remediated by the DPE wells is estimated to be 4.8 acres. Groundwater was extracted to recover nonaqueous phase and aqueous phase jet fuel from the shallow aquifer and treated above ground by the following processes; oil/water separation, iron-oxidation, flocculation, sedimentation, filtration, air stripping and liquid-phase granular activated carbon (LPGAC) adsorption. The extracted vapors were treated by vapor-phase granular activated carbon (VPGAC) adsorption in one area, and catalytic oxidation and VPGAC adsorption in another area. After 6 months of remediation, approximately 5,490 lbs. of volatile organic compounds (VOCs) were removed by soil vapor extraction (SVE), 109,650 lbs. of petroleum hydrocarbons were removed from the extracted groundwater, and 60,550 lbs. of petroleum hydrocarbons were biologically oxidized by subsurface microorganisms. Of these three mechanisms, the rate of petroleum hydrocarbon removal was the highest for biological oxidation in one area and by groundwater extraction in another area

Initiation of Positive Streamers near Uncharged Ice Hydrometeors in the Thundercloud Field

Science.gov (United States)

Babich, L. P.; Bochkov, E. I.

2018-05-01

Since the threshold electric field required for breakdown of air is much higher than the maximum field strength measured in thunderstorm clouds, the problem of lightning initiation still remains unsolved. According to the popular hypothesis, lightning can be initiated by a streamer discharge in the field enhanced near a hydrometeor. To verify the adequacy of this hypothesis, the development of a positive streamer propagating along the thunderstorm electric field in the vicinity of an ice needle at an air pressure corresponding to an altitude of 5 km (which is typical of the lightning initiation conditions) was simulated numerically. The hydrometeor dimensions are determined at which streamers can be initiated at different strengths of the thunderstorm electric field.

Initial magnetic field decay of the superconducting magnet in persistent current mode

International Nuclear Information System (INIS)

Yamamoto, S.; Yanada, T.

1988-01-01

The initial magnetic field decay in the persistent current mode of a magnetic resonance imaging magnet has been studied experimentally. The field decay is greater than the steady field decay due to joint resistances of conductors. Imaging experiments cannot be carried out during the periods, which last ten or more hours. The current distribution in the multifilamentory conductor is non-uniform just after the energization. It is suggested that the change of the current distribution causes the initial magnetic field decay. A 6th order superconducting magnet was prepared for experiments (central field = 0.35 T, inner diameters = 1 m, length = 1.86 m). The steady state magnetic field decay was 7*10/sup -8//hr. The initial magnetic field decay was 3*10/sup -6//hr. Overshoot currents (101 and 105 percent of the rated current) were applied to the magnet and the current reduced to the rated current to improve the initial decay. The energizing and de-energizing rate of the field was 1.8 gauss/second. No initial decay was observed when 105 percent current pattern was applied to the magnet

Full-field initialized decadal predictions with the MPI earth system model: an initial shock in the North Atlantic

Science.gov (United States)

Kröger, Jürgen; Pohlmann, Holger; Sienz, Frank; Marotzke, Jochem; Baehr, Johanna; Köhl, Armin; Modali, Kameswarrao; Polkova, Iuliia; Stammer, Detlef; Vamborg, Freja S. E.; Müller, Wolfgang A.

2017-12-01

Our decadal climate prediction system, which is based on the Max-Planck-Institute Earth System Model, is initialized from a coupled assimilation run that utilizes nudging to selected state parameters from reanalyses. We apply full-field nudging in the atmosphere and either full-field or anomaly nudging in the ocean. Full fields from two different ocean reanalyses are considered. This comparison of initialization strategies focuses on the North Atlantic Subpolar Gyre (SPG) region, where the transition from anomaly to full-field nudging reveals large differences in prediction skill for sea surface temperature and ocean heat content (OHC). We show that nudging of temperature and salinity in the ocean modifies OHC and also induces changes in mass and heat transports associated with the ocean flow. In the SPG region, the assimilated OHC signal resembles well OHC from observations, regardless of using full fields or anomalies. The resulting ocean transport, on the other hand, reveals considerable differences between full-field and anomaly nudging. In all assimilation runs, ocean heat transport together with net heat exchange at the surface does not correspond to OHC tendencies, the SPG heat budget is not closed. Discrepancies in the budget in the cases of full-field nudging exceed those in the case of anomaly nudging by a factor of 2-3. The nudging-induced changes in ocean transport continue to be present in the free running hindcasts for up to 5 years, a clear expression of memory in our coupled system. In hindcast mode, on annual to inter-annual scales, ocean heat transport is the dominant driver of SPG OHC. Thus, we ascribe a significant reduction in OHC prediction skill when using full-field instead of anomaly initialization to an initialization shock resulting from the poor initialization of the ocean flow.

Initial plasma production by induction electric field on QUEST tokamak

International Nuclear Information System (INIS)

Hasegawa, Makoto; Nakamura, Kazuo; Sato, Kohnosuke

2007-01-01

Induction electric field by center solenoid coil plays a roll to produce initial plasma. According to Townsend avalanche theory, minimum electric field for plasma breakdown depends on neutral gas pressure and connection length. On QUEST spherical tokamak, a connection length is evaluated as 966m on null point neighborhood with coil current ratio I PF26 /I CS =0.1, and induction electric field considering eddy current of vacuum vessel is evaluated as about 0.1 V/m on null point neighborhood. With Townsend avalanche theory, these values manage to produce initial plasma on QUEST. (author)

Ecohealth Field-building Leadership Initiative in Southeast Asia ...

International Development Research Centre (IDRC) Digital Library (Canada)

Ecohealth Field-building Leadership Initiative in Southeast Asia ... This grant will allow a consortium of research centres in China, Indonesia, Thailand ... Kunming Institute of Botany, Chinese Academy of Sciences as represented by Sun Hang.

Turbulent flow field structure of initially asymmetric jets

International Nuclear Information System (INIS)

Kim, Kyung Hoon; Kim, Bong Whan; Kim, Suk Woo

2000-01-01

The near field structure of round turbulent jets with initially asymmetric velocity distributions is investigated experimentally. Experiments are carried out using a constant temperature hot-wire anemomentry system to measure streamwise velocity in the jets. The measurements are undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distributions of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stresses. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend upstream of the exit. Three pipes used here include a straight pipe, and 90 and 160 degree-bend pipes. Therefore, at the upstream of the pipe exit, secondary flow through the bend and mean streamwise velocity distribution could be controlled by changing the curvature of pipes. The jets into the atmosphere have two levels of initial velocity skewness in addition to an axisymmetric jet from a straight pipe. In case of the curved pipe, a six diameterlong straight pipe section follows the bend upstream of the exit. The Reynolds number based on the exit bulk velocity is 13,400. The results indicate that the near field structure is considerably modified by the skewness of an initial mean velocity distribution. As the skewness increases, the decay rate of mean velocity at the centerline also increases

Calculation of the Initial Magnetic Field for Mercury's Magnetosphere Hybrid Model

Science.gov (United States)

Alexeev, Igor; Parunakian, David; Dyadechkin, Sergey; Belenkaya, Elena; Khodachenko, Maxim; Kallio, Esa; Alho, Markku

2018-03-01

Several types of numerical models are used to analyze the interactions of the solar wind flow with Mercury's magnetosphere, including kinetic models that determine magnetic and electric fields based on the spatial distribution of charges and currents, magnetohydrodynamic models that describe plasma as a conductive liquid, and hybrid models that describe ions kinetically in collisionless mode and represent electrons as a massless neutralizing liquid. The structure of resulting solutions is determined not only by the chosen set of equations that govern the behavior of plasma, but also by the initial and boundary conditions; i.e., their effects are not limited to the amount of computational work required to achieve a quasi-stationary solution. In this work, we have proposed using the magnetic field computed by the paraboloid model of Mercury's magnetosphere as the initial condition for subsequent hybrid modeling. The results of the model have been compared to measurements performed by the Messenger spacecraft during a single crossing of the magnetosheath and the magnetosphere. The selected orbit lies in the terminator plane, which allows us to observe two crossings of the bow shock and the magnetopause. In our calculations, we have defined the initial parameters of the global magnetospheric current systems in a way that allows us to minimize paraboloid magnetic field deviation along the trajectory of the Messenger from the experimental data. We have shown that the optimal initial field parameters include setting the penetration of a partial interplanetary magnetic field into the magnetosphere with a penetration coefficient of 0.2.

On the initial conditions of time-dependent mean-field equations of evolution. Pt. 2

International Nuclear Information System (INIS)

Troudet, T.; Paris-11 Univ., 91 - Orsay

1986-01-01

We analyze the problem so far untouched of determining the initial mean-field wavefunction in the context of zero-temperature mean-field descriptions of time-dependent expectation values and quantum fluctuations of nuclear observables. The nucleus, at zero temperature, is taken to be in a low-lying excited many-body eigenstate and is approximated by the corresponding RPA wavefunction as a continuous superposition of coherent states (i.e. Slater determinants). A generating function Gsub(A)(lambda) for time-dependent expectation values and quantum fluctuations is constructed within the formalism of functional integration. By applying the saddle-point method to the functional action of Gsub(A)(lambda) and then taking its lambda-derivatives, we recover the well-known TDHF theory and propose a simple determination of the initial Slater determinant for an appropriate mean-field description of time-dependent expectation values. The analog mean-field description of quadratic-quantum fluctuations proceeds similarly and in addition includes the contribution of the uncorrelated TDHF-RPA phonons coupled to collective excitations of the initial (static) mean-field configuration. When the collective TDHF-RPA excitations are solely taken into account, we obtain an improved version of the Balian-Veneroni dispersion formula by showing how to determine the initial mean-field wavefunction. By first taking the lambda-derivatives of Gsub(A)(lambda) before applying the saddle-point method, the initial mean-field wavefunction is found to be non-linearly coupled to the mean-field dynamics themselves. In return, and in contrast to the first quantization scheme, these both depend non-trivially upon the observable A being measured so that approximations must be proposed to simplify the resulting mean-field equations. (orig.)

British Isles Field Experience: An Initiative in International Education.

Science.gov (United States)

Martin, William J.

The British Isles Field Experience (BIFE) program was initiated at Williamsport Area Community College (WACC) to provide a group of WACC faculty and staff members with individual and group activities of a personal, professional, and cultural nature in order to promote an international perspective that can be infused into student, collegiate, and…

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

Energy Technology Data Exchange (ETDEWEB)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India)

2017-05-01

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections at the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.

The Frontier Fields: Survey Design and Initial Results

Energy Technology Data Exchange (ETDEWEB)

Lotz, J. M.; Koekemoer, A.; Grogin, N.; Mack, J.; Anderson, J.; Avila, R.; Barker, E. A.; Borncamp, D.; Durbin, M.; Gunning, H.; Hilbert, B.; Jenkner, H.; Khandrika, H.; Levay, Z.; Lucas, R. A.; MacKenty, J.; Ogaz, S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Coe, D.; Capak, P.; Brammer, G., E-mail: lotz@stsci.edu [European Space Agency/Space Telescope Science Institute, 3700 Sam Martin Drive, Baltimore, MD 21218 (United States); and others

2017-03-01

What are the faintest distant galaxies we can see with the Hubble Space Telescope ( HST ) now, before the launch of the James Webb Space Telescope ? This is the challenge taken up by the Frontier Fields, a Director’s discretionary time campaign with HST and the Spitzer Space Telescope to see deeper into the universe than ever before. The Frontier Fields combines the power of HST and Spitzer with the natural gravitational telescopes of massive high-magnification clusters of galaxies to produce the deepest observations of clusters and their lensed galaxies ever obtained. Six clusters—Abell 2744, MACSJ0416.1-2403, MACSJ0717.5+3745, MACSJ1149.5+2223, Abell S1063, and Abell 370—have been targeted by the HST ACS/WFC and WFC3/IR cameras with coordinated parallel fields for over 840 HST orbits. The parallel fields are the second-deepest observations thus far by HST with 5 σ point-source depths of ∼29th ABmag. Galaxies behind the clusters experience typical magnification factors of a few, with small regions magnified by factors of 10–100. Therefore, the Frontier Field cluster HST images achieve intrinsic depths of ∼30–33 mag over very small volumes. Spitzer has obtained over 1000 hr of Director’s discretionary imaging of the Frontier Field cluster and parallels in IRAC 3.6 and 4.5 μ m bands to 5 σ point-source depths of ∼26.5, 26.0 ABmag. We demonstrate the exceptional sensitivity of the HST Frontier Field images to faint high-redshift galaxies, and review the initial results related to the primary science goals.

Primordial non-Gaussianities in single field inflationary models with non-trivial initial states

Energy Technology Data Exchange (ETDEWEB)

Bahrami, Sina; Flanagan, Éanna É., E-mail: sb933@cornell.edu, E-mail: eef3@cornell.edu [Department of Physics, Cornell University, Ithaca, NY 14853 (United States)

2014-10-01

We compute the non-Gaussianities that arise in single field, slow roll inflationary models arising from arbitrary homogeneous initial states, as well as subleading contributions to the power spectrum. Non Bunch-Davies vacuum initial states can arise if the transition to the single field, slow roll inflation phase occurs only shortly before observable modes left the horizon. They can also arise from new physics at high energies that has been integrated out. Our general result for the bispectrum exhibits several features that were previously seen in special cases.

RECONSTRUCTING THE INITIAL DENSITY FIELD OF THE LOCAL UNIVERSE: METHODS AND TESTS WITH MOCK CATALOGS

International Nuclear Information System (INIS)

Wang Huiyuan; Mo, H. J.; Yang Xiaohu; Van den Bosch, Frank C.

2013-01-01

Our research objective in this paper is to reconstruct an initial linear density field, which follows the multivariate Gaussian distribution with variances given by the linear power spectrum of the current cold dark matter model and evolves through gravitational instabilities to the present-day density field in the local universe. For this purpose, we develop a Hamiltonian Markov Chain Monte Carlo method to obtain the linear density field from a posterior probability function that consists of two components: a prior of a Gaussian density field with a given linear spectrum and a likelihood term that is given by the current density field. The present-day density field can be reconstructed from galaxy groups using the method developed in Wang et al. Using a realistic mock Sloan Digital Sky Survey DR7, obtained by populating dark matter halos in the Millennium simulation (MS) with galaxies, we show that our method can effectively and accurately recover both the amplitudes and phases of the initial, linear density field. To examine the accuracy of our method, we use N-body simulations to evolve these reconstructed initial conditions to the present day. The resimulated density field thus obtained accurately matches the original density field of the MS in the density range 0.3∼ –1 , much smaller than the translinear scale, which corresponds to a wavenumber of ∼0.15 h Mpc –1

Bioremediation of Petroleum and Radiological Contaminated Soils at the Savannah River Site: Laboratory to Field Scale Applications

Energy Technology Data Exchange (ETDEWEB)

BRIGMON, ROBINL.

2004-06-07

In the process of Savannah River Site (SRS) operations limited amounts of waste are generated containing petroleum, and radiological contaminated soils. Currently, this combination of radiological and petroleum contaminated waste does not have an immediate disposal route and is being stored in low activity vaults. SRS developed and implemented a successful plan for clean up of the petroleum portion of the soils in situ using simple, inexpensive, bioreactor technology. Treatment in a bioreactor removes the petroleum contamination from the soil without spreading radiological contamination to the environment. This bioreactor uses the bioventing process and bioaugmentation or the addition of the select hydrocarbon degrading bacteria. Oxygen is usually the initial rate-limiting factor in the biodegradation of petroleum hydrocarbons. Using the bioventing process allowed control of the supply of nutrients and moisture based on petroleum contamination concentrations and soil type. The results of this work have proven to be a safe and cost-effective means of cleaning up low level radiological and petroleum-contaminated soil. Many of the other elements of the bioreactor design were developed or enhanced during the demonstration of a ''biopile'' to treat the soils beneath a Polish oil refinery's waste disposal lagoons. Aerobic microorganisms were isolated from the aged refinery's acidic sludge contaminated with polycyclic aromatic hydrocarbons (PAHs). Twelve hydrocarbon-degrading bacteria were isolated from the sludge. The predominant PAH degraders were tentatively identified as Achromobacter, Pseudomonas Burkholderia, and Sphingomonas spp. Several Ralstonia spp were also isolated that produce biosurfactants. Biosurfactants can enhance bioremediation by increasing the bioavailability of hydrophobic contaminants including hydrocarbons. The results indicated that the diversity of acid-tolerant PAH-degrading microorganisms in acidic oil wastes may

Broccoli (Brassica oleracea var. italica head initiation under field conditions

Directory of Open Access Journals (Sweden)

Alina Kałużewicz

2012-12-01

Full Text Available A two–year study on the influence of temperature on broccoli head initiation was carried out at the ''Marcelin'' experimental station of the Poznań University of Life Sciences. In each year of the study, plants were planted in the field at four dates. The evaluation of the developmental phase of the broccoli shoot apex was based on the analysis of microscope slides. The date of head initiation was assumed as the day on which the first of the examined apices were found to be at the early generative phase. The plant characteristics (number of leaves, leaf area and stem diameter on the date of initiation were also determined. Variation in length of the period from planting to head initiation was found both between dates of planting and between experimental years. The shortest period from planting to initiation was when the plants were planted in April and June (17-18 days in the first year and the longest one for planting in April in the first year of the study (29 days. The length of the period from planting to head initiation depended on mean daily air temperature. The higher the temperature was, the shorter was the period.

Restoration of the covariant gauge α in the initial field of gravity in de Sitter spacetime

Energy Technology Data Exchange (ETDEWEB)

Cheong, Lee Yen; Yan, Chew Xiao [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Tronoh 31750, Perak (Malaysia)

2014-03-05

The gravitational field generated by a mass term and the initial surface through covariant retarded Green's function for linearized gravity in de Sitter spacetime was studied recently [4, 5] with the covariant gauges set to β = 2/3 and α = 5/3. In this paper we extend the work to restore the gauge parameter α in the field coming from the initial data using the method of shifting the parameter. The α terms in the initial field cancels exactly with the one coming from the source term. Consequently, the correct field configuration, with two equal mass points moving in its geodesic, one located at the North pole and another one located at the South pole, is reproduced in the whole manifold of de Sitter spacetime.

Deep Vadose Zone–Applied Field Research Initiative Fiscal Year 2012 Annual Report

Energy Technology Data Exchange (ETDEWEB)

Wellman, Dawn M.; Truex, Michael J.; Johnson, Timothy C.; Bunn, Amoret L.; Golovich, Elizabeth C.

2013-03-14

This annual report describes the background of the Deep Vadose Zone-Applied Field Research Initiative, and some of the programmatic approaches and transformational technologies in groundwater and deep vadose zone remediation developed during fiscal year 2012.

Reconstructing the Initial Density Field of the Local Universe: Methods and Tests with Mock Catalogs

Science.gov (United States)

Wang, Huiyuan; Mo, H. J.; Yang, Xiaohu; van den Bosch, Frank C.

2013-07-01

Our research objective in this paper is to reconstruct an initial linear density field, which follows the multivariate Gaussian distribution with variances given by the linear power spectrum of the current cold dark matter model and evolves through gravitational instabilities to the present-day density field in the local universe. For this purpose, we develop a Hamiltonian Markov Chain Monte Carlo method to obtain the linear density field from a posterior probability function that consists of two components: a prior of a Gaussian density field with a given linear spectrum and a likelihood term that is given by the current density field. The present-day density field can be reconstructed from galaxy groups using the method developed in Wang et al. Using a realistic mock Sloan Digital Sky Survey DR7, obtained by populating dark matter halos in the Millennium simulation (MS) with galaxies, we show that our method can effectively and accurately recover both the amplitudes and phases of the initial, linear density field. To examine the accuracy of our method, we use N-body simulations to evolve these reconstructed initial conditions to the present day. The resimulated density field thus obtained accurately matches the original density field of the MS in the density range 0.3 \\lesssim \\rho /\\bar{\\rho } \\lesssim 20 without any significant bias. In particular, the Fourier phases of the resimulated density fields are tightly correlated with those of the original simulation down to a scale corresponding to a wavenumber of ~1 h Mpc-1, much smaller than the translinear scale, which corresponds to a wavenumber of ~0.15 h Mpc-1.

Influence of initial velocity on trajectories of a charged particle in uniform crossed electric and magnetic fields

International Nuclear Information System (INIS)

Khotimah, Siti Nurul; Viridi, Sparisoma; Widayani

2017-01-01

Magnetic and electric fields can cause a charged particle to form interesting trajectories. In general, each trajectory is discussed separately in university physics textbooks for undergraduate students. In this work, a solution of a charged particle moving in a uniform electric field at right angles to a uniform magnetic field (uniform crossed electric and magnetic fields) is reported; it is limited to particle motion in a plane. Specific solutions and their trajectories are obtained only by varying the initial particle velocity. The result shows five basic trajectory patterns, i.e., straight line, sinusoid-like, cycloid, cycloid-like with oscillation, and circle-like. The region of each trajectory is also mapped in the initial velocity space of the particle. This paper is intended for undergraduate students and describes further the trajectories of a charged particle through the regions of electric and magnetic fields influenced by initial condition of the particle, where electromagnetic radiation of an accelerated particle is not considered. (paper)

Effect of initial material on the electrolytic parameters of field-effect transistors

International Nuclear Information System (INIS)

Antonov, A.V.; Sinitsyn, V.N.; Fursov, V.V.

1978-01-01

The effect of initial material parameters upon the main electric characteristics of field transistors at room and optimum (170 deg C) temperatures is studied. For that purpose, the values of parasitic resistances rsub(s), specific resistances rho and steepness S of field transistors, depending on temperature and electrical conditions were measured. The output volt-ampere characteristics of the transistors at room and optimum temperatures are given. An analysis of the results obtained permits to conclude that there is an unambiguous relationship between rho and rsub(s). Impact ionization is shown to occur for field transistors with lower rho at lower drain voltage. When manufacturing field transistors designed for operation at low temperatures, one should remember that a minimum rho may restrict maximum possible steepness. When designing field transistors with optimum noise characteristics, one should variate not only such material parameters as mobility and carrier density, but also select optimum geometry

Initial particle loadings for a nonuniform simulation plasma in a magnetic field

International Nuclear Information System (INIS)

Naitou, Hiroshi; Kamimura, Tetsuo; Tokuda, Sinji.

1978-09-01

Improved methods for initially loading particles in a magnetized simulation plasma with nonuniform density and temperature distributions are proposed. In the usual guiding center loading (GCL), a charge separation coming from finite Larmor radius effects remains due to the difference between the guiding center density and the actual density. The modified guiding center loading (MGCL) presented here eliminates the electric field so generated and can be used for arbitrary density and temperature profiles. Some applications of these methods to actual simulations are given for comparison. The significance of these methods of initial particle loadings is also discussed. (author)

Scalar field cosmology: I. Asymptotic freedom and the initial-value problem

International Nuclear Information System (INIS)

Huang, Kerson; Low, Hwee-Boon; Tung, Roh-Suan

2012-01-01

The purpose of this work is to use a renormalized quantum scalar field to investigate very early cosmology, in the Planck era immediately following the big bang. Renormalization effects make the field potential dependent on length scale, and are important during the big bang era. We use the asymptotically free Halpern-Huang scalar field, which is derived from renormalization-group analysis, and solve Einstein's equation with Robertson-Walker metric as an initial-value problem. The main prediction is that the Hubble parameter follows a power law: H≡ a-dot /a∼t -p , and the universe expands at an accelerated rate: a ∼ expt 1-p . This gives 'dark energy', with an equivalent cosmological constant that decays in time like t -2p , which avoids the 'fine-tuning' problem. The power law predicts a simple relation for the galactic redshift. Comparison with data leads to the speculation that the universe experienced a crossover transition, which was completed about seven billion years ago. (paper)

X-Ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti-Galactic Center Fields

Science.gov (United States)

Hong, JaeSub; van den Berg, Maureen; Schlegel, Eric M.; Grindlay, Jonathan E.; Koenig, Xavier; Laycock, Silas; Zhao, Ping

2005-12-01

We describe the X-ray analysis procedure of the ongoing Chandra Multiwavelength Plane (ChaMPlane) Survey and report the initial results from the analysis of 15 selected anti-Galactic center observations (90degusing custom-developed analysis tools appropriate for Galactic sources but also of general use: optimum photometry in crowded fields using advanced techniques for overlapping sources, rigorous astrometry and 95% error circles for combining X-ray images or matching to optical/IR images, and application of quantile analysis for spectral analysis of faint sources. We apply these techniques to 15 anti-Galactic center observations (of 14 distinct fields), in which we have detected 921 X-ray point sources. We present logN-logS distributions and quantile analysis to show that in the hard band (2-8 keV) active galactic nuclei dominate the sources. Complete analysis of all ChaMPlane anti-Galactic center fields will be given in a subsequent paper, followed by papers on sources in the Galactic center and bulge regions.

Building the field of population health intervention research: The development and use of an initial set of competencies

Directory of Open Access Journals (Sweden)

Barbara Riley

2015-01-01

This initial set of competencies, released in 2013, may be used to develop graduate student curriculum, recruit trainees and faculty to academic institutions, plan non-degree professional development, and develop job descriptions for PHIR-related research and professional positions. The competencies provide some initial guideposts for the field and will need to be adapted as the PHIR field matures and to meet unique needs of different jurisdictions.

The Effect of Magnetic Field and Initial Stress on Fractional Order Generalized Thermoelastic Half-Space

Directory of Open Access Journals (Sweden)

Sunita Deswal

2013-01-01

Full Text Available The aim of this paper is to study magneto-thermoelastic interactions in an initially stressed isotropic homogeneous half-space in the context of fractional order theory of generalized thermoelasticity. State space formulation with the Laplace transform technique is used to obtain the general solution, and the resulting formulation is applied to the ramp type increase in thermal load and zero stress. Solutions of the problem in the physical domain are obtained by using a numerical method of the Laplace inverse transform based on the Fourier expansion technique, and the expressions for the displacement, temperature, and stress inside the half-space are obtained. Numerical computations are carried out for a particular material for illustrating the results. Results obtained for the field variables are displayed graphically. Some comparisons have been shown in figures to present the effect of fractional parameter, ramp parameter, magnetic field, and initial stress on the field variables. Some particular cases of special interest have been deduced from the present investigation.

Deep Vadose Zone-Applied Field Research Initiative Fiscal Year 2011 Annual Report

International Nuclear Information System (INIS)

Wellman, Dawn M.; Johnson, Timothy C.; Smith, Ronald M.; Truex, Michael J.; Matthews, Hope E.

2011-01-01

This annual report describes the background of the Deep Vadose Zone-Applied Field Research Initiative, and some of the programmatic approaches and transformational technologies in groundwater and deep vadose zone remediation developed during fiscal year 2011. The Department of Energy (DOE) Office of Technology Innovation and Development's (OTID) mission is to transform science into viable solutions for environmental cleanup. In 2010, OTID developed the Impact Plan, Science and Technology to Reduce the Life Cycle Cost of Closure to outline the benefits of research and development of the lifecycle cost of cleanup across the DOE complex. This plan outlines OTID's ability to reduce by $50 billion, the $200 billion life-cycle cost in waste processing, groundwater and soil, nuclear materials, and deactivation and decommissioning. The projected life-cycle costs and return on investment are based on actual savings realized from technology innovation, development, and insertion into remedial strategies and schedules at the Fernald, Mound, and Ashtabula sites. To achieve our goals, OTID developed Applied Field Research Initiatives to facilitate and accelerate collaborative development and implementation of new tools and approaches that reduce risk, cost and time for site closure. The primary mission of the Deep Vadose Zone-Applied Field Research Initiative (DVZ-AFRI) is to protect our nation's water resources, keeping them clean and safe for future generations. The DVZ-AFRI was established for the DOE to develop effective, science-based solutions for remediating, characterizing, monitoring, and predicting the behavior and fate of deep vadose zone contamination. Subsurface contaminants include radionuclides, metals, organics, and liquid waste that originated from various sources, including legacy waste from the nation's nuclear weapons complexes. The DVZ-AFRI project team is translating strategy into action by working to solve these complex challenges in a collaborative

Risk-based approach for bioremediation of fuel hydrocarbons at a major airport

International Nuclear Information System (INIS)

Wiedemeier, T.H.; Guest, P.R.; Blicker, B.R.

1994-01-01

This paper describes a risk-based approach for bioremediation of fuel-hydrocarbon-contaminated soil and ground water at a major airport in Colorado. In situ bioremediation pilot testing, natural attenuation modeling, and full-scale remedial action planning and implementation for soil and ground water contamination has conducted at four airport fuel farms. The sources of fuel contamination were leaking underground storage tanks (USTs) or pipelines transporting Jet A fuel and aviation gasoline. Continuing sources of contamination were present in several small cells of free-phase product and in fuel residuals trapped within the capillary fringe at depths 15 to 20 feet below ground surface. Bioventing pilot tests were conducted to assess the feasibility of using this technology to remediate contaminated soils. The pilot tests included measurement of initial soil gas chemistry at the site, determination of subsurface permeability, and in situ respiration tests to determine fuel biodegradation rates. A product recovery test was also conducted. ES designed and installed four full-scale bioventing systems to remediate the long-term sources of continuing fuel contamination. Benzene, toluene, ethylbenzene, and xylenes (BTEX) and total petroleum hydrocarbons (TPH) were detected in ground water at concentrations slightly above regulatory guidelines

Flight Muscle Dimorphism and Heterogeneity in Flight Initiation of Field-Collected Triatoma infestans (Hemiptera: Reduviidae)

OpenAIRE

Gurevitz, Juan M.; Kitron, Uriel; Gürtler, Ricardo E.

2007-01-01

Recent experiments demonstrated that most field-collected Triatoma infestans (Klug) (Hemiptera: Reduviidae) adults from northern Argentina either never initiated flight or did so repeatedly in both sexes. This pattern could not be explained by sex, adult age, weight, weight-to-length ratio (W/L), or chance. We examined whether bugs that never initiated flight possessed developed flight muscles, and whether flight muscle mass relative to total body mass (FMR) was related to the probability of ...

Ørsted Initial Field Model

DEFF Research Database (Denmark)

Olsen, Nils; Holme, R.; Hulot, G.

2000-01-01

Magnetic measurements taken by the Orsted satellite during geomagnetic quiet conditions around January 1, 2000 have been used to derive a spherical harmonic model of the Earth's magnetic field for epoch 2000.0. The maximum degree and order of the model is 19 for internal, and 2 for external, source...... fields; however, coefficients above degree 14 may not be robust. Such a detailed model exists for only one previous epoch, 1980. Achieved rms misfit is ... to the Orsted mission, this model supercedes IGRF 2000....

Preparing beginning reading teachers: An experimental comparison of initial early literacy field experiences

OpenAIRE

Al Otaiba, Stephanie; Lake, Vickie E.; Greulich, Luana; Folsom, Jessica S.; Guidry, Lisa

2012-01-01

This randomized-control trial examined the learning of preservice teachers taking an initial Early Literacy course in an early childhood education program and of the kindergarten or first grade students they tutored in their field experience. Preservice teachers were randomly assigned to one of two tutoring programs: Book Buddies and Tutor Assisted Intensive Learning Strategies (TAILS), which provided identical meaning-focused instruction (shared book reading), but differed ...

Scientific investigation plan for initial engineered barrier system field tests

International Nuclear Information System (INIS)

Wunan Lin.

1993-02-01

The purpose of this Scientific Investigation Plan (SIP) is to describe tests known as Initial Engineered Barrier System Field Tests (IEBSFT) and identified by Work Breakdown Structure as WBS 1.2.2.2.4. The IEBSFT are precursors to the Engineered Barrier System Field Test (EBSFT), WBS 1.2.2.2.4, to be conducted in the Exploratory Study Facility (ESF) at Yucca Mountain. The EBSFT and IEBSFT are designed to provide information on the interaction between waste packages (simulated by heated containers) and the surrounding rock mass, its vadose water, and infiltrated water. Heater assemblies will be installed in drifts or boreholes openings and heated to measure moisture movement during heat-up and subsequent cool-down of the rock mass. In some of the tests, infiltration of water into the heated rock mass will be studied. Throughout the heating and cooling cycle, instruments installed in the rock will monitor such parameters as temperature, moisture content, concentration of some chemical species, and stress and strain. Rock permeability measurements, rock and fluid (water and gas) sampling, and fracture pattern measurements will also be made before and after the test

Building the field of population health intervention research: The development and use of an initial set of competencies.

Science.gov (United States)

Riley, Barbara; Harvey, Jean; Di Ruggiero, Erica; Potvin, Louise

2015-01-01

Population health intervention research (PHIR) is a relatively new research field that studies interventions that can improve health and health equity at a population level. Competencies are one way to give legitimacy and definition to a field. An initial set of PHIR competencies was developed with leadership from a multi-sector group in Canada. This paper describes the development process for these competencies and their possible uses. Methods to develop the competencies included key informant interviews; a targeted review of scientific and gray literature; a 2-round, online adapted Delphi study with a 24-member panel; and a focus group with 9 international PHIR experts. The resulting competencies consist of 25 items grouped into 6 categories. They include principles of good science applicable though not exclusive to PHIR, and more suitable for PHIR teams rather than individuals. This initial set of competencies, released in 2013, may be used to develop graduate student curriculum, recruit trainees and faculty to academic institutions, plan non-degree professional development, and develop job descriptions for PHIR-related research and professional positions. The competencies provide some initial guideposts for the field and will need to be adapted as the PHIR field matures and to meet unique needs of different jurisdictions.

Initial Characterization of Colombian High School Physics Teachers' Pedagogical Content Knowledge on Electric Fields

Science.gov (United States)

Melo-Niño, Lina Viviana; Cañada, Florentina; Mellado, Vicente

2017-01-01

We explore the initial characterization of the pedagogical content knowledge of four, in-service, Colombian pre-university secondary education physics teachers on the concept of electric field. Two of them teach the content in English as a second language. The aim of the study was to obtain an image of the participants' teaching of electric field…

Initial Characterization of Colombian High School Physics Teachers' Pedagogical Content Knowledge on Electric Fields

Science.gov (United States)

Melo-Niño, Lina Viviana; Cañada, Florentina; Mellado, Vicente

2017-02-01

We explore the initial characterization of the pedagogical content knowledge of four, in-service, Colombian pre-university secondary education physics teachers on the concept of electric field. Two of them teach the content in English as a second language. The aim of the study was to obtain an image of the participants' teaching of electric field and the inherent complexities that go with that. The results revealed that factors which involved their personal educational models, such as, how they interpret their school's curriculum, the relationship they see between physics and mathematics, the most effective strategies for teaching physics, and the time they have available to develop the topic played a significant role. The teachers considered it essential to establish new strategies that would motivate the pupils by helping them visualize the electric field.

Inflation with generalized initial conditions

International Nuclear Information System (INIS)

Albrecht, A.; Brandenberger, R.; Matzner, R.

1987-01-01

In many current models of the early Universe a scalar field phi which is only very weakly coupled to other quantum fields is used to generate inflation. In such models there are no forces which could thermalize the scalar field, and previous assumptions about its preinflation ''initial'' conditions must be abandoned. In this paper the onset of inflation is studied classically for more general initial conditions of the scalar field configuration. In particular, initial conditions with a nonvanishing spatial average of phi, with phi chosen at random in each initial horizon volume, and with random initial momenta are considered. We identify and discuss several mechanisms that can drive these more general initial conditions toward an inflationary state. The analysis is done in one spatial dimension

Novel Field test design and initial result for AC and DC characterization for PV-panels

DEFF Research Database (Denmark)

Thorsteinsson, Sune; Riedel, Nicholas; Santamaria Lancia, Adrian Alejo

This work describes the design and initial test results of a field test for PV modules, where the PV modules the majority of the time operates to produce power at their maximum power point. Sequentially the individual modules are switched into a measurement circuitry for IV curves and impedance s...

Preliminary investigation of the structural influence of entry-entry intersections and inhomogeneous initial-stress fields on repository disposal rooms

International Nuclear Information System (INIS)

Loken, M.C.

1983-07-01

The structural influence of entry-entry intersections and inhomogeneous initial stress fields on a repository configuration has been investigated. The out-of-plane stress increases rapidly into the pillar from the rib of the connecting corridor to the plane strain value within one pillar width of the intersection, indicating that a two-dimensional analysis is valid over a major portion of the disposal room and pillar. Inhomogeneous initial stress fields do not significantly alter the trends of the resulting post-excavation stress fields. However, the magnitude of the vertical stress and the effective stress is slightly greater near the corner at the intersection. Further nonlinear analyses are required to assess the stability of the pillar at the intersection because of the high deviatoric stresses occurring in that region. 6 references

Effect of initial void shape on ductile failure in a shear field

DEFF Research Database (Denmark)

Tvergaard, Viggo

2015-01-01

For voids in a shear field unit cell model analyses have been used to show that ductile failure is predicted even though the stress triaxiality is low or perhaps negative, so that the void volume fraction does not grow during deformation. Here, the effect of the void shape is studied by analyzing...... with circular cross-section, i.e. the voids in shear flatten out to micro-cracks, which rotate and elongate until interaction with neighboring micro-cracks gives coalescence. Even though the mechanism of ductile failure is the same, the load carrying capacity predicted, for the same initial void volume fraction...

A content analysis of dissemination and implementation science resource initiatives: what types of resources do they offer to advance the field?

Science.gov (United States)

Darnell, Doyanne; Dorsey, Caitlin N; Melvin, Abigail; Chi, Jonathan; Lyon, Aaron R; Lewis, Cara C

2017-11-21

The recent growth in organized efforts to advance dissemination and implementation (D & I) science suggests a rapidly expanding community focused on the adoption and sustainment of evidence-based practices (EBPs). Although promising for the D & I of EBPs, the proliferation of initiatives is difficult for any one individual to navigate and summarize. Such proliferation may also result in redundant efforts or missed opportunities for participation and advancement. A review of existing D & I science resource initiatives and their unique merits would be a significant step for the field. The present study aimed to describe the global landscape of these organized efforts to advance D & I science. We conducted a content analysis between October 2015 and March 2016 to examine resources and characteristics of D & I science resource initiatives using public, web-based information. Included resource initiatives must have engaged in multiple efforts to advance D & I science beyond conferences, offered D & I science resources, and provided content in English. The sampling method included an Internet search using D & I terms and inquiry among internationally representative D & I science experts. Using a coding scheme based on a priori and grounded approaches, two authors consensus coded website information including interactive and non-interactive resources and information regarding accessibility (membership, cost, competitive application, and location). The vast majority (83%) of resource initiatives offered at least one of seven interactive resources (consultation/technical assistance, mentorship, workshops, workgroups, networking, conferences, and social media) and one of six non-interactive resources (resource library, news and updates from the field, archived talks or slides, links pages, grant writing resources, and funding opportunities). Non-interactive resources were most common, with some appearing frequently across resource initiatives (e.g., news and updates from the

Initial Results from the Vector Electric Field Investigation on the C/NOFS Satellite

Science.gov (United States)

Pfaff, R.; Rowland, D.; Acuna, M.; Le, G.; Farrell, W.; Holzworth, R.; Wilson, G.; Burke, W.; Freudenreich, H.; Bromund, K.;

A content analysis of dissemination and implementation science resource initiatives: what types of resources do they offer to advance the field?

Directory of Open Access Journals (Sweden)

Doyanne Darnell

2017-11-01

Full Text Available Abstract Background The recent growth in organized efforts to advance dissemination and implementation (D & I science suggests a rapidly expanding community focused on the adoption and sustainment of evidence-based practices (EBPs. Although promising for the D & I of EBPs, the proliferation of initiatives is difficult for any one individual to navigate and summarize. Such proliferation may also result in redundant efforts or missed opportunities for participation and advancement. A review of existing D & I science resource initiatives and their unique merits would be a significant step for the field. The present study aimed to describe the global landscape of these organized efforts to advance D & I science. Methods We conducted a content analysis between October 2015 and March 2016 to examine resources and characteristics of D & I science resource initiatives using public, web-based information. Included resource initiatives must have engaged in multiple efforts to advance D & I science beyond conferences, offered D & I science resources, and provided content in English. The sampling method included an Internet search using D & I terms and inquiry among internationally representative D & I science experts. Using a coding scheme based on a priori and grounded approaches, two authors consensus coded website information including interactive and non-interactive resources and information regarding accessibility (membership, cost, competitive application, and location. Results The vast majority (83% of resource initiatives offered at least one of seven interactive resources (consultation/technical assistance, mentorship, workshops, workgroups, networking, conferences, and social media and one of six non-interactive resources (resource library, news and updates from the field, archived talks or slides, links pages, grant writing resources, and funding opportunities. Non-interactive resources were most common, with some appearing frequently across

Initial Results of the SSPX Transient Internal Probe System for Measuring Toroidal Field Profiles

Science.gov (United States)

Holcomb, C. T.; Jarboe, T. R.; Mattick, A. T.; Hill, D. N.; McLean, H. S.; Wood, R. D.; Cellamare, V.

2000-10-01

Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. The Sustained Spheromak Physics Experiment (SSPX) is using a field profile diagnostic called the Transient Internal Probe (TIP). TIP consists of a verdet-glass bullet that is used to measure the magnetic field by Faraday rotation. This probe is shot through the spheromak by a light gas gun at speeds near 2 km/s. An argon laser is aligned along the path of the probe. The light passes through the probe and is retro-reflected to an ellipsometer that measures the change in polarization angle. The measurement is spatially resolved down to the probes’ 1 cm length to within 15 Gauss. Initial testing results are given. This and future data will be used to determine the field profile for equilibrium reconstruction. TIP can also be used in conjunction with wall probes to map out toroidal mode amplitudes and phases internally. This work was performed under the auspices of US DOE by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.

Effect of Surface Tension Anisotropy and Welding Parameters on Initial Instability Dynamics During Solidification: A Phase-Field Study

Science.gov (United States)

Yu, Fengyi; Wei, Yanhong

2018-05-01

The effects of surface tension anisotropy and welding parameters on initial instability dynamics during gas tungsten arc welding of an Al-alloy are investigated by a quantitative phase-field model. The results show that the surface tension anisotropy and welding parameters affect the initial instability dynamics in different ways during welding. The surface tension anisotropy does not influence the solute diffusion process but does affect the stability of the solid/liquid interface during solidification. The welding parameters affect the initial instability dynamics by varying the growth rate and thermal gradient. The incubation time decreases, and the initial wavelength remains stable as the welding speed increases. When welding power increases, the incubation time increases and the initial wavelength slightly increases. Experiments were performed for the same set of welding parameters used in modeling, and the results of the experiments and simulations were in good agreement.

Positive streamer initiation from raindrops in thundercloud fields

DEFF Research Database (Denmark)

Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

2016-01-01

required for the streamer formation is larger than the measured thunderstorm fields. Therefore, the results of simulations suggest that second mechanisms must operate to amplify the local field. Such mechanisms could be electric field space variations via collective effects of many hydrometeors or runaway...

Independence and Interdependence: An Analysis of Pre-Service Candidates' Use of Focused Assignments on an Electronic Discussion Forum during the Initial Field Experience

Science.gov (United States)

Fisch, Audrey A.; Bennett, Deborah J.

2011-01-01

This article describes a case study using an electronic learning platform for creating an interactive learning community through asynchronous discussion to enhance the initial field experience of secondary math and English teacher candidates enrolled in Field Experience. We identified three problems with the field experience course--lack of…

Initial geomagnetic field model from Magsat vector data

Science.gov (United States)

Langel, R. A.; Mead, G. D.; Lancaster, E. R.; Estes, R. H.; Fabiano, E. B.

1980-01-01

Magsat data from the magnetically quiet days of November 5-6, 1979, were used to derive a thirteenth degree and order spherical harmonic geomagnetic field model, MGST(6/80). The model utilized both scalar and high-accuracy vector data and fit that data with root-mean-square deviations of 8.2, 6.9, 7.6 and 7.4 nT for the scalar magnitude, B(r), B(theta), and B(phi), respectively. The model includes the three first-order coefficients of the external field. Comparison with averaged Dst indicates that zero Dst corresponds with 25 nT of horizontal field from external sources. When compared with earlier models, the earth's dipole moment continues to decrease at a rate of about 26 nT/yr. Evaluation of earlier models with Magsat data shows that the scalar field at the Magsat epoch is best predicted by the POGO(2/72) model but that the WC80, AWC/75 and IGS/75 are better for predicting vector fields.

Reduction of initial shock in decadal predictions using a new initialization strategy

Science.gov (United States)

He, Yujun; Wang, Bin; Liu, Mimi; Liu, Li; Yu, Yongqiang; Liu, Juanjuan; Li, Ruizhe; Zhang, Cheng; Xu, Shiming; Huang, Wenyu; Liu, Qun; Wang, Yong; Li, Feifei

2017-08-01

A novel full-field initialization strategy based on the dimension-reduced projection four-dimensional variational data assimilation (DRP-4DVar) is proposed to alleviate the well-known initial shock occurring in the early years of decadal predictions. It generates consistent initial conditions, which best fit the monthly mean oceanic analysis data along the coupled model trajectory in 1 month windows. Three indices to measure the initial shock intensity are also proposed. Results indicate that this method does reduce the initial shock in decadal predictions by Flexible Global Ocean-Atmosphere-Land System model, Grid-point version 2 (FGOALS-g2) compared with the three-dimensional variational data assimilation-based nudging full-field initialization for the same model and is comparable to or even better than the different initialization strategies for other fifth phase of the Coupled Model Intercomparison Project (CMIP5) models. Better hindcasts of global mean surface air temperature anomalies can be obtained than in other FGOALS-g2 experiments. Due to the good model response to external forcing and the reduction of initial shock, higher decadal prediction skill is achieved than in other CMIP5 models.

Initial ionization stage of FRC formation

International Nuclear Information System (INIS)

Commisso, R.J.; Armstrong, W.T.; Cochrane, J.C.; Ekdahl, C.A.; Lipson, J.; Linford, R.K.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

1980-01-01

A Field-Reversed Configuration (FRC) is a prolate compact torus that is confined by poloidal fields only. Theta-pinch formation of an FRC employs an initial bias field, B 1 , whose direction is opposite to that of the main theta-pinch field. Some fraction of the flux associated with this bias field eventually constitutes the closed-field-line flux of the FRC. Experimental and theoretical evidence suggest that the longest-lived FRC's are obtained when the closed flux is maximized. Because the initial ionization is done in the presence of the bias field, the actual bias flux available at the time of application of the main theta-pinch field depends strongly on the initial ionization, or preionization, technique used. In this paper we report on experiments characterizing the previously used theta-pinch preionization technique that employed a net field (bias plus preionization) null, or zero-crossing, of the axial component of the magnetic field to break down the gas. We also discuss results of experiments designed to develop preionization techniques in which the gas breakdown is not accomplished by a zero-crossing

Transient loss of plasma from a theta pinch having an initially reversed magnetic field

International Nuclear Information System (INIS)

Heidrich, J.E.

1981-01-01

The results of an experimental study of the transient loss of plasma from a 25-cm-long theta pinch initially containing a reversed trapped magnetic field are presented. The plasma, amenable to MHD analyses, was a doubly ionized helium plasma characterized by an ion density N/sub i/ = 2 x 10 16 cm -3 and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10 16 cm -3 and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil

Automated Identification of Initial Storm Electrification and End-of-Storm Electrification Using Electric Field Mill Sensors

Science.gov (United States)

Maier, Launa M.; Huddleston, Lisa L.

2017-01-01

Kennedy Space Center (KSC) operations are located in a region which experiences one of the highest lightning densities across the United States. As a result, on average, KSC loses almost 30 minutes of operational availability each day for lightning sensitive activities. KSC is investigating using existing instrumentation and automated algorithms to improve the timeliness and accuracy of lightning warnings. Additionally, the automation routines will be warning on a grid to minimize under-warnings associated with not being located in the center of the warning area and over-warnings associated with encompassing too large an area. This study discusses utilization of electric field mill data to provide improved warning times. Specifically, this paper will demonstrate improved performance of an enveloping algorithm of the electric field mill data as compared with the electric field zero crossing to identify initial storm electrification. End-of-Storm-Oscillation (EOSO) identification algorithms will also be analyzed to identify performance improvement, if any, when compared with 30 minutes after the last lightning flash.

Final Confirmation Sampling and Analysis Report for the POL Yard, Sites SS-06 and ST-40, Wurtsmith AFB, Michigan

National Research Council Canada - National Science Library

1999-01-01

.... Wurtsmith AFBCA and AFCEE/ERT had no comments on the draft final report. This report represents the final contract deliverable for the AFCEE Extended Bioventing Project at the Wurtsmith AFB POL Yard...

Initial ionization stage of FRC formation

Energy Technology Data Exchange (ETDEWEB)

Commisso, R.J.; Armstrong, W.T.; Cochrane, J.C.; Ekdahl, C.A.; Lipson, J.; Linford, R.K.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

1980-01-01

A Field-Reversed Configuration (FRC) is a prolate compact torus that is confined by poloidal fields only. Theta-pinch formation of an FRC employs an initial bias field, B/sub 1/, whose direction is opposite to that of the main theta-pinch field. Some fraction of the flux associated with this bias field eventually constitutes the closed-field-line flux of the FRC. Experimental and theoretical evidence suggest that the longest-lived FRC's are obtained when the closed flux is maximized. Because the initial ionization is done in the presence of the bias field, the actual bias flux available at the time of application of the main theta-pinch field depends strongly on the initial ionization, or preionization, technique used. In this paper we report on experiments characterizing the previously used theta-pinch preionization technique that employed a net field (bias plus preionization) null, or zero-crossing, of the axial component of the magnetic field to break down the gas. We also discuss results of experiments designed to develop preionization techniques in which the gas breakdown is not accomplished by a zero-crossing.

Initial behavior of a quantized scalar field the associated pair-creation in several anisotropic universes

International Nuclear Information System (INIS)

Nariai, Hidekazu

1981-01-01

As a sequel to previous works on the definition of a positive frequency part of a quantized scalar field near an initial stage of several Robertson-Walker universes with flat, open or closed 3-space and the associated pair-creation of those particles, an attempt is made to seek for the same concept in several Bianchi-type I anisotropic universes. It is shown that, if the positive frequency part is introduced, the pair-creation of scalar particles and their spectral law are uniquely determined, as in the case of isotropic universes. (author)

Free massless fields of arbitrary spin in the de Sitter space and initial data for a higher spin superalgebra

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, M A

1987-11-01

Linearized curvatures are constructed for massless higher spin fields on the (anti-) de Sitter background. The quite uniform description for free massless fields of all integer and half-integer spins s greater than or equal to 3/2 is presented, based on these curvatures. In particular, the actions and the equations of motion are given in a simple form. The proposed linearized curvatures provide 'initial data' for determination of a non-Abelian higher spin symmetry that may correspond to a hypothetical non-trivial theory of higher spins interacting with gravity and themselves. It is noted that the conjugation law for fermion fields should be modified drastically after transition from the anti-de-Sitter geometry to the de Sitter one.

Initial field measurements on the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Ormrod, J.H.; Chan, K.C.; Hill, J.H.

1980-12-01

The midplane magnetic field of the Chalk River superconducting cyclotron has been mapped in detail over the full operating range of 2.5 to 5 tesla. The field measuring apparatus is described and results given include measurements of the field stability, reproducibility and harmonic content. (author)

The magnetic field investigation on the ARASE (ERG) mission: Data characteristics and initial scientific results

Science.gov (United States)

Matsuoka, A.; Teramoto, M.; Nomura, R.; Nose, M.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Nagatsuma, T.; Shiokawa, K.; Obana, Y.; Miyoshi, Y.; Takashima, T.; Shinohara, I.

2017-12-01

The ARASE (ERG) satellite was successfully launched on December 20 2016. A fluxgate magnetometer (MGF) was built for the ARASE satellite to measure DC and low-frequency magnetic field. The requirements to the magnetic field measurements by ARASE was defined as (1) accuracy of the absolute field intensity is within 5 nT (2) angular accuracy of the field direction is within 1 degree (3) measurement frequency range is from DC to 60Hz or wider. MGF measures the vector magnetic field with the original sampling frequency of 256 Hz. The dynamic range is switched between +/-8000nT and +/- 60000nT according to the background field intensity. The MGF initial checkout was carried on January 10th 2017, when the MGF normal performance and downlinked data were confirmed. The 5-m length MAST for the sensor was deployed on 17th January. The nominal operation of MGF started in March 2017. The MGF data are calibrated based on the results from the ground experiments and in-orbit data analysis. The MGF CDF files are distributed by the ARASE Science Center and available by Space Physics Environment Data Analysis Software (SPEDAS). The acceleration process of the charged particles in the inner magnetosphere is considered to be closely related to the deformation and perturbation of the magnetic field. Accurate measurement of the magnetic field is required to understand the acceleration mechanism of the charged particles, which is one of the major scientific objectives of the ARASE mission. We designed a fluxgate magnetometer which is optimized to investigate following topics; (1) accurate measurement of the background magnetic field - the deformation of the magnetic field and its relationship with the particle acceleration. (2) MHD waves - measurement of the ULF electromagnetic waves of frequencies about 1mHz (Pc4-5), and investigation of the radiation-belt electrons radially diffused by the resonance with the ULF waves. (3) EMIC waves - measurement of the electromagnetic ion

Part 2: A field study of enhanced remediation of Toluene in the vadose zone using a nutrient solution

Science.gov (United States)

Tindall, J.A.; Weeks, E.P.; Friedel, M.

2005-01-01

The objective of this study was to test the effectiveness of a nitrate-rich nutrient solution and hydrogen peroxide (H2O2) to enhance in-situ microbial remediation of toluene in the unsaturated zone. Three sand-filled plots were tested in three phases (each phase lasting approximately 2 weeks). During the control phase, toluene was applied uniformly via sprinkler irrigation. Passive remediation was allowed to occur during this phase. A modified Hoagland nutrient solution, concentrated in 150 L of water, was tested during the second phase. The final phase involved addition of 230 moles of H2O2 in 150 L of water to increase the available oxygen needed for aerobic biodegradation. During the first phase, measured toluene concentrations in soil gas were reduced from 120 ppm to 25 ppm in 14 days. After the addition of nutrients during the second phase, concentrations were reduced from 90 ppm to about 8 ppm within 14 days, and for the third phase (H 2O2), toluene concentrations were about 1 ppm after only 5 days. Initial results suggest that this method could be an effective means of remediating a contaminated site, directly after a BTEX spill, without the intrusiveness and high cost of other abatement technologies such as bioventing or soil-vapor extraction. However, further tests need to be completed to determine the effect of each of the BTEX components. ?? Springer 2005.

Confirmation Sampling and Analysis Plan for Spill Site Number 1

National Research Council Canada - National Science Library

1998-01-01

... No. 1 to document the effectiveness of bioventing for the remediation of petroleum-hydrocarbon-contaminated soils and to provide data for a risk-based assessment of contaminants remaining in site soils and groundwater. Spill Site...

Microphysical and Kinematic Characteristics of Regions of Flash Initiation in a Supercell Storm and a Multicell Storm Observed During the DC3 Field Program

Science.gov (United States)

DiGangi, E.; MacGorman, D. R.; Ziegler, C.; Betten, D.; Biggerstaff, M. I.

2017-12-01

Lightning initiation in thunderstorms requires that the local electric field magnitude exceed breakdown values somewhere, and this tends to occur between regions of positive and negative charge, where the largest electric field magnitudes tend to occur. Past studies have demonstrated that, near updrafts, storms with very strong updrafts tend to elevate regions of charge and of flash initiations higher, as well as to have more flashes initiated by small pockets of charge, than in storms with much weaker updrafts. In all thunderstorms, the source of these charge regions is generally thought to be microscopic charge separation via the relative growth rate noninductive mechanism, followed by macroscopic charge separation via sedimentation, although other charge generation mechanisms can contribute to charge in some regions. Charge generation and lightning initiation are therefore inherently dependent on the microphysical and kinematic characteristics of a given storm. This study compares the results of a hydrometeor classification algorithm applied to C-band mobile radar data with mixing ratios calculated by a diabatic Lagrangian analysis retrieval from the dual-Doppler wind fields for two storms, the 29-30 May 2012 supercell storm and the 21 June 2012 multicell storm, observed during the Deep Convective Clouds and Chemistry experiment. Using these data, we then compare the inferred microphysical and kinematic characteristics of regions in which the Oklahoma Lightning Mapping Array indicated that flashes were initiated in these two very different storms.

Robustness of inflation to inhomogeneous initial conditions

Energy Technology Data Exchange (ETDEWEB)

Clough, Katy; Lim, Eugene A. [Theoretical Particle Physics and Cosmology Group, Physics Department, Kings College London, Strand, London WC2R 2LS (United Kingdom); DiNunno, Brandon S.; Fischler, Willy; Flauger, Raphael; Paban, Sonia, E-mail: katy.clough@kcl.ac.uk, E-mail: eugene.a.lim@gmail.com, E-mail: bsd86@physics.utexas.edu, E-mail: fischler@physics.utexas.edu, E-mail: flauger@physics.utexas.edu, E-mail: paban@physics.utexas.edu [Department of Physics, The University of Texas at Austin, Austin, TX, 78712 (United States)

2017-09-01

We consider the effects of inhomogeneous initial conditions in both the scalar field profile and the extrinsic curvature on different inflationary models. In particular, we compare the robustness of small field inflation to that of large field inflation, using numerical simulations with Einstein gravity in 3+1 dimensions. We find that small field inflation can fail in the presence of subdominant gradient energies, suggesting that it is much less robust to inhomogeneities than large field inflation, which withstands dominant gradient energies. However, we also show that small field inflation can be successful even if some regions of spacetime start out in the region of the potential that does not support inflation. In the large field case, we confirm previous results that inflation is robust if the inflaton occupies the inflationary part of the potential. Furthermore, we show that increasing initial scalar gradients will not form sufficiently massive inflation-ending black holes if the initial hypersurface is approximately flat. Finally, we consider the large field case with a varying extrinsic curvature K , such that some regions are initially collapsing. We find that this may again lead to local black holes, but overall the spacetime remains inflationary if the spacetime is open, which confirms previous theoretical studies.

IN SITU BIOREMEDIATION STRATEGIES FOR ORGANIC WOOD PRESERVATIVES

Science.gov (United States)

Laboratory biotreatability studies evaluated the use of bioventing and biosparging plus groundwater circulation (UVB technology) for their potential abililty to treat soil and groundwater containing creosote and pentachlorophenol. Soils from two former wood-treatment facilities w...

Soil and Sediment remediation, mechanisms, technologies and applications

NARCIS (Netherlands)

Lens, P.N.L.; Grotenhuis, J.T.C.; Malina, G.; Tabak, H.H.

2005-01-01

Technologies for the treatment of soils and sediments in-situ (landfarming, bioscreens, bioventing, nutrient injection, phytoremediation) and ex-situ (landfarming, bio-heap treatment, soil suspension reactor) will be discussed. The microbiological, process technological and socio-economical aspects

Dynamics of leaf and spikelet primordia initiation in wheat as affected by Ppd-1a alleles under field conditions.

Science.gov (United States)

Ochagavía, Helga; Prieto, Paula; Savin, Roxana; Griffiths, Simon; Slafer, GustavoA

2018-04-27

Wheat adaptation is affected by Ppd genes, but the role of these alleles in the rates of leaf and spikelet initiation has not been properly analysed. Twelve near isogenic lines (NILs) combining Ppd-1a alleles from different donors introgressed in A, B, and/or D genomes were tested under field conditions during two growing seasons together with the wild type, Paragon. Leaf initiation rate was unaffected by Ppd-1a alleles so the final leaf number (FLN) was reduced in parallel with reductions in the duration of the vegetative phase. Spikelet primordia initiation was accelerated and consequently the effect on spikelets per spike was less than proportional to the effect on the duration of spikelet initiation. The magnitude of these effects on spikelet plastochron depended on the doses of Ppd-1 homoeoalleles and the specific insensitivity alleles carried. Double ridge was consistently later than floral initiation, but the difference between them was not affected by Ppd-1a alleles. These findings have potential for selecting the best combinations from the Ppd-1 homoeoallelic series for manipulating adaptation taking into consideration particular effects on spikelet number.

Citizen participation and citizen initiatives

International Nuclear Information System (INIS)

Matthoefer, H.

1977-01-01

Contents: Social conditions for citizen initiatives - technical change and employment - crisis behaviour - socio-psychological analysis of political planning; legitimation - presentation and criticism - conditions for citizen initiatives coming into being within the field of tension citizen : administration - legal problems of citizen initiatives - environmental protection in the energy discussion; participation; models. (HP) [de

Monitoring of Gasoline-ethanol Degradation In Undisturbed Soil

Science.gov (United States)

Österreicher-Cunha, P.; Nunes, C. M. F.; Vargas, E. A.; Guimarães, J. R. D.; Costa, A.

Environmental contamination problems are greatly emphasised nowadays because of the direct threat they represent for human health. Traditional remediation methods fre- quently present low efficiency and high costs; therefore, biological treatment is being considered as an accessible and efficient alternative for soil and water remediation. Bioventing, commonly used to remediate petroleum hydrocarbon spills, stimulates the degradation capacity of indigenous microorganisms by providing better subsur- face oxygenation. In Brazil, gasoline and ethanol are mixed (78:22 v/v); some authors indicate that despite gasoline high degradability, its degradation in subsurface is hin- dered by the presence of much more rapidly degrading ethanol. Contaminant distribu- tion and degradation in the subsurface can be monitored by several physical, chemical and microbiological methodologies. This study aims to evaluate and follow the degra- dation of a gasoline-ethanol mixture in a residual undisturbed tropical soil from Rio de Janeiro. Bioventing was used to enhance microbial degradation. Shifts in bacte- rial culturable populations due to contamination and treatment effects were followed by conventional microbiology methods. Ground Penetrating Radar (GPR) measure- ments, which consist of the emission of electro-magnetic waves into the soil, yield a visualisation of contaminant degradation because of changes in soil conductivity due to microbial action on the pollutants. Chemical analyses will measure contaminant residue in soil. Our results disclosed contamination impact as well as bioventing stim- ulation on soil culturable heterotrophic bacterial populations. This multidisciplinary approach allows for a wider evaluation of processes occurring in soil.

Alliance members' roles in collective field-building: an assessment of leadership and championship within the Population Health Intervention Research Initiative for Canada.

Science.gov (United States)

Di Ruggiero, Erica; Kishchuk, Natalie; Viehbeck, Sarah; Edwards, Nancy; Robinson, Kerry; Riley, Barbara; Fowler, Heather Smith

2017-12-06

The Population Health Intervention Research Initiative for Canada (PHIRIC) is a multi-stakeholder alliance founded in 2006 to advance population health intervention research (PHIR). PHIRIC aimed to strengthen Canada's capacity to conduct and use such research to inform policy and practice to improve the public's health by building PHIR as a field of research. In 2014, an evaluative study of PHIRIC at organisational and system levels was conducted, guided by a field-building and collaborative action perspective. The study involved 17 qualitative key informant interviews with 21 current and former PHIRIC Planning Committee and Working Group members. The interviews examined how individuals and organisations were acting as champions and exerting leadership in building the field of PHIR. Founding PHIRIC organisational members have been championing PHIR at organisational and system levels. While the PHIR field has progressed in terms of enhanced funding, legitimacy, profile and capacity, some members and organisations faced constraints and challenges acting as leaders and champions in their respective environments. Expectations about the future of PHIRIC and field-building of PHIR were mixed, where longer-term and founding members of PHIRIC expressed more optimism than recent members. All agreed on the need for incorporating perspectives of decision-makers into PHIR directions and initiatives. The findings contribute to understanding alliance members' roles in leadership and championship for field-building more generally, and for population health and PHIR specifically. Building this field requires multi-level efforts, collaborative action and distributed leadership to create the necessary conditions for PHIRIC members to both benefit from and contribute to advancing PHIR as a field. Lessons from this 'made in Canada' model may be of interest to other countries regarding the structures needed for PHIR field-building.

Trapped field recovery of bulk superconductor magnets by static field magnetization

Energy Technology Data Exchange (ETDEWEB)

Deng, Z., E-mail: zigang@kaiyodai.ac.jp [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan); Tsuzuki, K.; Miki, M.; Felder, B.; Hara, S.; Izumi, M. [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan)

2011-11-15

A series of initial trapped fields after ZFC or FC magnetization are used to simulate the attenuated trapped field. It is possible and easy to recover the lost trapped field and regain the best trapped field performance as before. In the re-magnetization process, the initial magnetic flux inside the bulk magnets will help to recover the trapped field. The optimum recovery field is recommended to be 2.5 times the saturation field of the bulk at LN2 temperature. Thanks to the trapped field of bulk high-temperature superconductors, they can be used as field-pole magnets in the high temperature superconducting (HTS) rotating machines. For example, an output power of 10 kW at 720 rpm was realized by an average trapped field of 0.56 T of eight melt-textured GdBa{sub 2}Cu{sub 3}O{sub y} (Gd-123) bulks at liquid nitrogen temperature in TUMSAT in 2004. Similarly to the HTS machines involving 1G or 2G wires, the trapped field of the bulk is possibly sensitive and even can be attenuated by the AC component field during the operation. Hence, it is necessary to recover the trapped field once being decreased to some extent in the practical application. From this point, we have investigated the trapped field recovery of HTS bulk magnets by static field magnetization in the paper. A series of different initial trapped fields after zero-field-cooling or field-cooling magnetization are used to simulate the attenuated trapped field. By comparing the trapped field peak and its distribution, the trapped field was found to be able to recover by the static field magnetization method with a stronger excitation field and the initial trapped flux inside the bulk also has an influence on the recovery process. The optimum recovery field was found to be about 2.5 times the saturated trapped field of the bulk at liquid nitrogen temperature, by which the bulk can regain the former best trapped field performance.

Developing and Field Testing a Community Based Youth Initiative to Increase Tuberculosis Awareness in Remote Arctic Inuit Communities.

Science.gov (United States)

Alvarez, Gonzalo G; Van Dyk, Deborah D; Colquhoun, Heather; Moreau, Katherine A; Mulpuru, Sunita; Graham, Ian D

2016-01-01

Inuit in Canada have the highest reported tuberculosis (TB) incidence rate in Canada, even higher than other Canadian Indigenous groups. The aim of this study was to increase TB awareness among Inuit youth and their communities by equipping those who can best reach this population with a community based, youth focused, education initiative built on interventions adapted from a previous TB awareness study. The Taima TB Youth Education Initiative was a field test case study of a knowledge translation (KT) strategy aimed at community members who provide health education in these communities. In the first stage of this study, interventions from a larger TB awareness campaign were adapted to focus on youth living in remote Inuit communities. During the second stage of the study, investigators field tested the initiative in two isolated Inuit communities. It was then applied by local implementation teams in two other communities. Evaluation criteria included feasibility, acceptability, knowledge uptake and health behavior change. Implementation of the adapted KT interventions resulted in participation of a total of 41 youth (19 females, 22 males) with an average age of 16 years (range 12-21 years) in four different communities in Nunavut. Community celebration events were attended by 271 community members where TB messaging were presented and discussed. All of the health care workers and community members surveyed reported that the adapted interventions were acceptable and a useful way of learning to some extent. Knowledge uptake measures indicated an average TB knowledge score of 64 out of 100. Local partners in all four communities indicated that they would use the Taima TB Youth Education Initiative again to raise awareness about TB among youth in their communities. The TB awareness interventions adapted for the Taima TB Youth Education Initiative were acceptable to the Inuit communities involved in the study. They resulted in uptake of knowledge among participants

Initial Field Test of a Cloud-Based Cardiac Auscultation System to Determine Murmur Etiology in Rural China.

Science.gov (United States)

Pyles, Lee; Hemmati, Pouya; Pan, J; Yu, Xiaoju; Liu, Ke; Wang, Jing; Tsakistos, Andreas; Zheleva, Bistra; Shao, Weiguang; Ni, Quan

2017-04-01

A system for collection, distribution, and long distant, asynchronous interpretation of cardiac auscultation has been developed and field-tested in rural China. We initiated a proof-of-concept test as a critical component of design of a system to allow rural physicians with little experience in evaluation of congenital heart disease (CHD) to obtain assistance in diagnosis and management of children with significant heart disease. The project tested the hypothesis that acceptable screening of heart murmurs could be accomplished using a digital stethoscope and internet cloud transmittal to deliver phonocardiograms to an experienced observer. Of the 7993 children who underwent school-based screening in the Menghai District of Yunnan Province, Peoples Republic of China, 149 had a murmur noted by a screener. They had digital heart sounds and phonocardiograms collected with the HeartLink tele auscultation system, and underwent echocardiography by a cardiology resident from the First Affiliated Hospital of Kunming Medical University. The digital phonocardiograms, stored on a cloud server, were later remotely reviewed by a board-certified American pediatric cardiologist. Fourteen of these subjects were found to have CHD confirmed by echocardiogram. Using the HeartLink system, the pediatric cardiologist identified 11 of the 14 subjects with pathological murmurs, and missed three subjects with atrial septal defects, which were incorrectly identified as venous hum or Still's murmur. In addition, ten subjects were recorded as having pathological murmurs, when no CHD was confirmed by echocardiography during the field study. The overall test accuracy was 91% with 78.5% sensitivity and 92.6% specificity. This proof-of-concept study demonstrated the feasibility of differentiating pathologic murmurs due to CHD from normal functional heart murmurs with the HeartLink system. This field study is an initial step to develop a cost-effective CHD screening strategy in low

APPLICATION STRATEGIES AND DESIGN CRITERIA FOR IN SITU BIOREMEDIATION OF SOIL AND GROUNDWATER IMPACTED BY PAHS

Science.gov (United States)

Biotreatability studies conducted in our laboratory used soils from two former wood-treatment facilities to evaluate the use of in situ bioventing and biosparging applications for their potential ability to remediate soil and groundwater containing creosote. The combination of ph...

Exo-electrons and initiation of electric discharges

International Nuclear Information System (INIS)

Laube, Sylvain

1992-01-01

As some observations seemed to indicate that glass submitted to an electric field could be a source of electrons, and that any dielectric could play the role, this research thesis aimed at verifying this hypothesis, at least for two industrially used dielectrics (Teflon and Kapton). The author also shows the advantage which could be taken from such an emission, as well in the field of electric discharges as in the field of their applications. Electrons emitted in such conditions are herein called exo-electrons. In a first part, the author analysed the characteristic magnitudes which govern the conditions of discharge initiation, i.e. the initiation voltage and the statistic delay between the application of an electric field and the initiative occurrence. The second part presents the different measurements devices which have been designed, and the third part presents and discusses experimental results, and shows that the theoretical model is in compliance with initiation voltage measurements. As far as electron emission is concerned, a possible explication of this phenomenon is proposed [fr

Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment

International Nuclear Information System (INIS)

Reass, W.A.; Miera, D.A.; Wurden, G.A.

1997-01-01

This paper presents the initial electrical and mechanical design of two phase-locked 30 Megawatt RMS, 150 kHz oscillator systems used for current drive and plasma sustainment of the ''Translation, Confinement, and Sustainment'' (TCS) field reversed configuration (FRC) plasma. By the application of orthogonally-placed saddle coils on the surface of the glass vacuum vessel, the phase-controlled rotating magnetic field perturbation will induce an electric field in the plasma which should counter the intrinsic ohmic decay of the plasma, and maintain the FRC. Each system utilizes a bank of 6 parallel magnetically beamed ML8618 triodes. These devices are rated at 250 Amperes cathode current and a 45 kV plate voltage. An advantage of the magnetically beamed triode is their extreme efficiency, requiring only 2.5 kW of filament and a few amps and a few kV of grid drive. Each 3.5 uH saddle coil is configured with an adjustable tank circuit (for tuning). Assuming no losses and a nominal 18 kV plate voltage, the tubes can circulate about 30 kV and 9 kA (pk to pk) in the saddle coil antenna, a circulating power of over 33 megawatts RMS. On each cycle the tubes can kick in up to 1500 Amperes, providing a robust phase control. DC high-voltage from the tubes is isolated from the saddle coil antennas and tank circuits by a 1:1 coaxial air-core balun transformer. To control the ML8618's phase and amplitude, fast 150 Ampere ''totem-pole'' grid drivers, an ''on'' hot-deck and an ''off'' hot-deck are utilized. The hot-decks use up to 6 each 3CPX1500A7 slotted radial beam triodes. By adjusting the conduction angle, amplitude may be regulated, with inter-pulse timing, phase angle can be controlled. A central feedback timing chassis monitors each systems' saddle coil antenna and appropriately derives each systems timing signals. Fiber-optic cables are used to isolate between the control room timing chassis and the remote power oscillator system. Complete system design detail will be

Initial states in integrable quantum field theory quenches from an integral equation hierarchy

Directory of Open Access Journals (Sweden)

D.X. Horváth

2016-01-01

Full Text Available We consider the problem of determining the initial state of integrable quantum field theory quenches in terms of the post-quench eigenstates. The corresponding overlaps are a fundamental input to most exact methods to treat integrable quantum quenches. We construct and examine an infinite integral equation hierarchy based on the form factor bootstrap, proposed earlier as a set of conditions determining the overlaps. Using quenches of the mass and interaction in Sinh-Gordon theory as a concrete example, we present theoretical arguments that the state has the squeezed coherent form expected for integrable quenches, and supporting an Ansatz for the solution of the hierarchy. Moreover we also develop an iterative method to solve numerically the lowest equation of the hierarchy. The iterative solution along with extensive numerical checks performed using the next equation of the hierarchy provides a strong numerical evidence that the proposed Ansatz gives a very good approximation for the solution.

Use of Iodine-based contrast media in digital full-field mammography - initial experience

International Nuclear Information System (INIS)

Diekmann, F.; Diekmann, S.; Taupitz, M.; Bick, U.; Winzer, K.-J.; Huettner, C.; Muller, S.; Jeunehomme, F.; Hamm, B.

2003-01-01

Aim: To investigate the use of iodine-based contrast media in digital full-field mammography. Methods: After performing initial phantom studies, seven patients underwent digital mammography (Senographe 2000D, GE Medical Systems, Milwaukee, USA) using a specially filtered beam before as well as 60, 120, and 180 seconds after injection of 80 ml of iodine contrast medium (Ultravist 370, Schering AG, Germany). The precontrast mammograms were then subtracted from the postcontrast mammograms and the resulting images compared with a contrast-enhanced dynamic MRI study, performed on all women. Results: Contrast medium accumulation within the tumors was visualized with a good quality in all cases. The conditions under which successful contrast-enhanced digital mammography can be performed were determined in phantom studies. Conclusions: Contrast-enhanced digital mammography has a potential for improving the visualization of breast tumors in mammography using special beam filtering, adjusted X-ray parameters, proper timing, and suitable subtraction software. (orig.) [de

Initial states in integrable quantum field theory quenches from an integral equation hierarchy

Energy Technology Data Exchange (ETDEWEB)

Horváth, D.X., E-mail: esoxluciuslinne@gmail.com [MTA-BME “Momentum” Statistical Field Theory Research Group, Budafoki út 8, 1111 Budapest (Hungary); Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, 1111 Budapest (Hungary); Sotiriadis, S., E-mail: sotiriad@sissa.it [SISSA and INFN, Via Bonomea 265, 34136 Trieste (Italy); Takács, G., E-mail: takacsg@eik.bme.hu [MTA-BME “Momentum” Statistical Field Theory Research Group, Budafoki út 8, 1111 Budapest (Hungary); Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, 1111 Budapest (Hungary)

2016-01-15

We consider the problem of determining the initial state of integrable quantum field theory quenches in terms of the post-quench eigenstates. The corresponding overlaps are a fundamental input to most exact methods to treat integrable quantum quenches. We construct and examine an infinite integral equation hierarchy based on the form factor bootstrap, proposed earlier as a set of conditions determining the overlaps. Using quenches of the mass and interaction in Sinh-Gordon theory as a concrete example, we present theoretical arguments that the state has the squeezed coherent form expected for integrable quenches, and supporting an Ansatz for the solution of the hierarchy. Moreover we also develop an iterative method to solve numerically the lowest equation of the hierarchy. The iterative solution along with extensive numerical checks performed using the next equation of the hierarchy provides a strong numerical evidence that the proposed Ansatz gives a very good approximation for the solution.

Accelerated expansion of the Universe without an inflaton and resolution of the initial singularity from Group Field Theory condensates

Directory of Open Access Journals (Sweden)

Marco de Cesare

2017-01-01

Full Text Available We study the expansion of the Universe using an effective Friedmann equation obtained from the dynamics of GFT (Group Field Theory isotropic condensates. The evolution equations are classical, with quantum correction terms to the Friedmann equation given in the form of effective fluids coupled to the emergent classical background. The occurrence of a bounce, which resolves the initial spacetime singularity, is shown to be a general property of the model. A promising feature of this model is the occurrence of an era of accelerated expansion, without the need to introduce an inflaton field with an appropriately chosen potential. We discuss possible viability issues of this scenario as an alternative to inflation.

Evolution of solar magnetic fields - A new approach to MHD initial-boundary value problems by the method of nearcharacteristics

Science.gov (United States)

Nakagawa, Y.

1980-01-01

A method of analysis for the MHD initial-boundary problem is presented in which the model's formulation is based on the method of nearcharacteristics developed by Werner (1968) and modified by Shin and Kot (1978). With this method, the physical causality relationship can be traced from the perturbation to the response as in the method of characteristics, while achieving the advantage of a considerable reduction in mathematical procedures. The method offers the advantage of examining not only the evolution of nonforce free fields, but also the changes of physical conditions in the atmosphere accompanying the evolution of magnetic fields. The physical validity of the method is demonstrated with examples, and their significance in interpreting observations is discussed.

Inhomogeneous inflation: The initial-value problem

International Nuclear Information System (INIS)

Laguna, P.; Kurki-Suonio, H.; Matzner, R.A.

1991-01-01

We present a spatially three-dimensional study for solving the initial-value problem in general relativity for inhomogeneous cosmologies. We use York's conformal approach to solve the constraint equations of Einstein's field equations for scalar field sources and find the initial data which will be used in the evolution. This work constitutes the first stage in the development of a code to analyze the effects of matter and spacetime inhomogeneities on inflation

Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results

Science.gov (United States)

Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.; Ridley, A. J.

2009-01-01

Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored.

Continuum and Discrete Initial-Boundary Value Problems and Einstein's Field Equations

Directory of Open Access Journals (Sweden)

Olivier Sarbach

2012-08-01

Full Text Available Many evolution problems in physics are described by partial differential equations on an infinite domain; therefore, one is interested in the solutions to such problems for a given initial dataset. A prominent example is the binary black-hole problem within Einstein's theory of gravitation, in which one computes the gravitational radiation emitted from the inspiral of the two black holes, merger and ringdown. Powerful mathematical tools can be used to establish qualitative statements about the solutions, such as their existence, uniqueness, continuous dependence on the initial data, or their asymptotic behavior over large time scales. However, one is often interested in computing the solution itself, and unless the partial differential equation is very simple, or the initial data possesses a high degree of symmetry, this computation requires approximation by numerical discretization. When solving such discrete problems on a machine, one is faced with a finite limit to computational resources, which leads to the replacement of the infinite continuum domain with a finite computer grid. This, in turn, leads to a discrete initial-boundary value problem. The hope is to recover, with high accuracy, the exact solution in the limit where the grid spacing converges to zero with the boundary being pushed to infinity. The goal of this article is to review some of the theory necessary to understand the continuum and discrete initial boundary-value problems arising from hyperbolic partial differential equations and to discuss its applications to numerical relativity; in particular, we present well-posed initial and initial-boundary value formulations of Einstein's equations, and we discuss multi-domain high-order finite difference and spectral methods to solve them.

Continuum and Discrete Initial-Boundary Value Problems and Einstein's Field Equations.

Science.gov (United States)

Sarbach, Olivier; Tiglio, Manuel

2012-01-01

Many evolution problems in physics are described by partial differential equations on an infinite domain; therefore, one is interested in the solutions to such problems for a given initial dataset. A prominent example is the binary black-hole problem within Einstein's theory of gravitation, in which one computes the gravitational radiation emitted from the inspiral of the two black holes, merger and ringdown. Powerful mathematical tools can be used to establish qualitative statements about the solutions, such as their existence, uniqueness, continuous dependence on the initial data, or their asymptotic behavior over large time scales. However, one is often interested in computing the solution itself, and unless the partial differential equation is very simple, or the initial data possesses a high degree of symmetry, this computation requires approximation by numerical discretization. When solving such discrete problems on a machine, one is faced with a finite limit to computational resources, which leads to the replacement of the infinite continuum domain with a finite computer grid. This, in turn, leads to a discrete initial-boundary value problem. The hope is to recover, with high accuracy, the exact solution in the limit where the grid spacing converges to zero with the boundary being pushed to infinity. The goal of this article is to review some of the theory necessary to understand the continuum and discrete initial boundary-value problems arising from hyperbolic partial differential equations and to discuss its applications to numerical relativity; in particular, we present well-posed initial and initial-boundary value formulations of Einstein's equations, and we discuss multi-domain high-order finite difference and spectral methods to solve them.

A brave new world: considering the pedagogic potential of Virtual World Field Trips (VWFTs in initial teacher education

Directory of Open Access Journals (Sweden)

Fitzsimons Sabrina

2016-07-01

Full Text Available In its broadest and historical sense, place-based education refers to education that occurs outside of the physical boundaries of a school building (Dewey 1910; Sobel 1996; Theobald 1997; Woodhouse and Knapp 2000. Place-based education, colloquially referred to as the ‘field trip’, is predominantly considered a pedagogic tool of the sciences. It involves a physical movement from the school-based location to a place of interest, for example, a geography field trip to an ecological landscape or science visit to a local museum. This paper considers the use of virtual world field trips (VWFTs within the context of a pre-service Teacher Education programme. The paper presents data from one undergraduate module offered on a programme of initial teacher education. The paper identifies three significant elements of virtual world field trips: place, people and content. First, the virtual world can provide access to places not possible in the offline context as a result of geographic, economic or religious factors. Second, exposure to and dialogue with a variety of world views can challenge students’ assumptions, facilitate reflection and provide an opportunity for oneto-one teaching encounters. Third, from a teacher educator perspective, engagement in virtual world field trips can provide a space for teachers to model teaching methodologies and model creative learning techniques, thus providing student teachers with an insight into different approaches to teaching.

Assisted bioremediation tests on three natural soils contaminated with benzene

Directory of Open Access Journals (Sweden)

Maria Manuela Carvalho

2015-07-01

Full Text Available Bioremediation is an attractive and useful method of remediation of soils contaminated with petroleum hydrocarbons because it is simple to maintain, applicable in large areas, is economic and enables an effective destruction of the contaminant. Usually, the autochthone microorganisms have no ability to degrade these compounds, and otherwise, the contaminated sites have inappropriate environmental conditions for microorganism’s development. These problems can be overcome by assisted bioremediation (bioaugmentation and/or biostimulation. In this study the assisted bioremediation capacity on the rehabilitation of three natural sub-soils (granite, limestone and schist contaminated with benzene was evaluated. Two different types of assisted bioremediation were used: without and with ventilation (bioventing. The bioaugmentation was held by inoculating the soil with a consortium of microorganisms collected from the protection area of crude oil storage tanks in a refinery. In unventilated trials, biostimulation was accomplished by the addition of a nutrient mineral media, while in bioventing oxygen was also added. The tests were carried out at controlled temperature of 25 ºC in stainless steel columns where the moist soil contaminated with benzene (200 mg per kg of soil occupied about 40% of the column’s volume. The processes were daily monitored in discontinued mode. Benzene concentration in the gas phase was quantified by gas chromatography (GC-FID, oxygen and carbon dioxide concentrations were monitored by respirometry. The results revealed that the three contaminated soils were remediated using both technologies, nevertheless, the bioventing showed faster rates. With this work it was proved that respirometric analysis is an appropriate instrument for monitoring the biological activity.

The NuSTAR Extragalactic Surveys: Initial Results and Catalog from the Extended Chandra Deep Field South

DEFF Research Database (Denmark)

Mullaney, J. R.; Del-Moro, A.; Aird, J.

2015-01-01

We present the initial results and the source catalog from the Nuclear Spectroscopic Telescope Array (NuSTAR) survey of the Extended Chandra Deep Field South (hereafter, ECDFS)—currently the deepest contiguous component of the NuSTAR extragalactic survey program. The survey covers the full ≈30......V fluxes) span the range L10 40 keV (0.7 300) 10 erg s» - ´ 43 1 -- ,sampling below the “knee” of the X-ray luminosity function out to z ~ 0.8-1. Finally, we identify oneNuSTAR source that has neither a Chandra nor an XMM-Newton counterpart, but that shows evidence of nuclearactivity at infrared...

Tripolar electric field Structure in guide field magnetic reconnection

OpenAIRE

S. Fu; S. Huang; M. Zhou; B. Ni; X. Deng

2018-01-01

It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplit...

Wetting front instability in an initially wet unsaturated fracture

International Nuclear Information System (INIS)

Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

1992-01-01

Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

Wetting front instability in an initially wet unsaturated fracture

International Nuclear Information System (INIS)

Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

1993-01-01

Experimental results exploring gravity-driven wetting from instability in a pre-wetted, rough-walled analog fractures such as those at Yucca Mountain are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

Wire Probe Antenna (WPT) and Electric Field Detector (EFD) of Plasma Wave Experiment (PWE) aboard the Arase satellite: specifications and initial evaluation results

Science.gov (United States)

Kasaba, Yasumasa; Ishisaka, Keigo; Kasahara, Yoshiya; Imachi, Tomohiko; Yagitani, Satoshi; Kojima, Hirotsugu; Matsuda, Shoya; Shoji, Masafumi; Kurita, Satoshi; Hori, Tomoaki; Shinbori, Atsuki; Teramoto, Mariko; Miyoshi, Yoshizumi; Nakagawa, Tomoko; Takahashi, Naoko; Nishimura, Yukitoshi; Matsuoka, Ayako; Kumamoto, Atsushi; Tsuchiya, Fuminori; Nomura, Reiko

2017-12-01

This paper summarizes the specifications and initial evaluation results of Wire Probe Antenna (WPT) and Electric Field Detector (EFD), the key components for the electric field measurement of the Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite. WPT consists of two pairs of dipole antennas with 31-m tip-to-tip length. Each antenna element has a spherical probe (60 mm diameter) at each end of the wire (15 m length). They are extended orthogonally in the spin plane of the spacecraft, which is roughly perpendicular to the Sun and enables to measure the electric field in the frequency range of DC to 10 MHz. This system is almost identical to the WPT of Plasma Wave Investigation aboard the BepiColombo Mercury Magnetospheric Orbiter, except for the material of the spherical probe (ERG: Al alloy, MMO: Ti alloy). EFD is a part of the EWO (EFD/WFC/OFA) receiver and measures the 2-ch electric field at a sampling rate of 512 Hz (dynamic range: ± 200 mV/m) and the 4-ch spacecraft potential at a sampling rate of 128 Hz (dynamic range: ± 100 V and ± 3 V/m), with the bias control capability of WPT. The electric field waveform provides (1) fundamental information about the plasma dynamics and accelerations and (2) the characteristics of MHD and ion waves in various magnetospheric statuses with the magnetic field measured by MGF and PWE-MSC. The spacecraft potential provides information on thermal electron plasma variations and structure combined with the electron density obtained from the upper hybrid resonance frequency provided by PWE-HFA. EFD has two data modes. The continuous (medium-mode) data are provided as (1) 2-ch waveforms at 64 Hz (in apoapsis mode, L > 4) or 256 Hz (in periapsis mode, L < 4), (2) 1-ch spectrum within 1-232 Hz with 1-s resolution, and (3) 4-ch spacecraft potential at 8 Hz. The burst (high-mode) data are intermittently obtained as (4) 2-ch waveforms at 512 Hz and (5) 4-ch spacecraft potential at 128 Hz and downloaded with the WFC

An initial response of magnetic fields at geosynchronous orbit to Pi 2 onset as observed from the dip-equator

Directory of Open Access Journals (Sweden)

O. Saka

1998-05-01

Full Text Available Fluxgate magnetometer data recorded at the dip-equator (Huancayo, Peru; 1.44°N, 355.9° in geomagnetic coordinates; 12.1°S, 75.2°W in geographic coordinates; L = 1.00 with higher accuracy of timing (0.1 s and amplitude resolution (0.01 nT were utilized to survey an onset of Pi 2 pulsations in the midnight sector (2100–0100 LT during PROMIS (Polar Region and Outer Magnetosphere International Study periods (1 March–20 June, 1986. It is found that changing field line magnitude and vector as observed by magnetometer on board the synchronous satellites in the midnight sector often takes place simultaneously with the onset of Pi 2 pulsations at the dip-equator. The field disturbances that follow thereafter tend to last for some time both at the geosynchronous altitudes and the dip-equator. In this report, we examine the initial response of the field lines in space, and attempt to classify how the field line vector changed in the meridional plane. Key words. Magnetospheric physics · Magnetospheric configuration and dynamics · MHD waves and instabilities · Plasmasphere

An initial response of magnetic fields at geosynchronous orbit to Pi 2 onset as observed from the dip-equator

Directory of Open Access Journals (Sweden)

O. Saka

Full Text Available Fluxgate magnetometer data recorded at the dip-equator (Huancayo, Peru; 1.44°N, 355.9° in geomagnetic coordinates; 12.1°S, 75.2°W in geographic coordinates; L = 1.00 with higher accuracy of timing (0.1 s and amplitude resolution (0.01 nT were utilized to survey an onset of Pi 2 pulsations in the midnight sector (2100–0100 LT during PROMIS (Polar Region and Outer Magnetosphere International Study periods (1 March–20 June, 1986. It is found that changing field line magnitude and vector as observed by magnetometer on board the synchronous satellites in the midnight sector often takes place simultaneously with the onset of Pi 2 pulsations at the dip-equator. The field disturbances that follow thereafter tend to last for some time both at the geosynchronous altitudes and the dip-equator. In this report, we examine the initial response of the field lines in space, and attempt to classify how the field line vector changed in the meridional plane.

Key words. Magnetospheric physics · Magnetospheric configuration and dynamics · MHD waves and instabilities · Plasmasphere

Soil remediation via bioventing, vapor extraction and transition regime between vapor extraction and bioventing

Directory of Open Access Journals (Sweden)

Mohammad Mehdi Amin

2014-01-01

Conclusion: Comparison of the BV, SVE and AIBV technologies indicated that all of those technologies are efficient for remediation of unsaturated zone, but after specific remediation time frames, only AIBV able to support guide line values and protect ground waters.

Tensor-based morphometry with mappings parameterized by stationary velocity fields in Alzheimer's disease neuroimaging initiative.

Science.gov (United States)

Bossa, Matías Nicolás; Zacur, Ernesto; Olmos, Salvador

2009-01-01

Tensor-based morphometry (TBM) is an analysis technique where anatomical information is characterized by means of the spatial transformations between a customized template and observed images. Therefore, accurate inter-subject non-rigid registration is an essential prerrequisite. Further statistical analysis of the spatial transformations is used to highlight some useful information, such as local statistical differences among populations. With the new advent of recent and powerful non-rigid registration algorithms based on the large deformation paradigm, TBM is being increasingly used. In this work we evaluate the statistical power of TBM using stationary velocity field diffeomorphic registration in a large population of subjects from Alzheimer's Disease Neuroimaging Initiative project. The proposed methodology provided atrophy maps with very detailed anatomical resolution and with a high significance compared with results published recently on the same data set.

Current initiatives in the mass production and field release of the Mexican fruit fly, Anastrepha ludens, in the lower Rio Grande valley of Texas

International Nuclear Information System (INIS)

Worley, J.N.; Forrester, O.T.

1999-01-01

In order to reduce the program operating expenses in the South Texas Mexican Fruit Fly Sterile Release Program, four cost reduction initiatives are in progress at the U.S. Department of Agriculture's Mexican Fruit Fly Rearing Facility. These initiatives include implementation of a less expensive larval diet formulation, automation of the larval diet dispensing process, processing and reutilization of spent larval diet medium, and a more efficient system for emerging and feeding sterile flies prior to field release. (author)

EXPERIENCES WITH IDEA PROMOTING INITIATIVES

DEFF Research Database (Denmark)

Gish, Liv

2011-01-01

In new product development a central activity is to provide new ideas. Over the last decades experiences with stimulating employee creativity and establishing idea promoting initiatives have been made in industrial practice. Such initiatives are often labeled Idea Management – a research field...... with a growing interest. In this paper I examine three different idea promoting initiatives carried out in Grundfos, a leading pump manufacturer. In the analysis I address what understandings of idea work are inscribed in the initiatives and what role these initiatives play in the organization with respect...... understandings of idea work are inscribed in the idea promoting initiatives as they to some degree have to fit with the understandings embedded in practice in order to work....

Full-field and anomaly initialization using a low-order climate model: a comparison and proposals for advanced formulations

Science.gov (United States)

Carrassi, A.; Weber, R. J. T.; Guemas, V.; Doblas-Reyes, F. J.; Asif, M.; Volpi, D.

2014-04-01

Initialization techniques for seasonal-to-decadal climate predictions fall into two main categories; namely full-field initialization (FFI) and anomaly initialization (AI). In the FFI case the initial model state is replaced by the best possible available estimate of the real state. By doing so the initial error is efficiently reduced but, due to the unavoidable presence of model deficiencies, once the model is let free to run a prediction, its trajectory drifts away from the observations no matter how small the initial error is. This problem is partly overcome with AI where the aim is to forecast future anomalies by assimilating observed anomalies on an estimate of the model climate. The large variety of experimental setups, models and observational networks adopted worldwide make it difficult to draw firm conclusions on the respective advantages and drawbacks of FFI and AI, or to identify distinctive lines for improvement. The lack of a unified mathematical framework adds an additional difficulty toward the design of adequate initialization strategies that fit the desired forecast horizon, observational network and model at hand. Here we compare FFI and AI using a low-order climate model of nine ordinary differential equations and use the notation and concepts of data assimilation theory to highlight their error scaling properties. This analysis suggests better performances using FFI when a good observational network is available and reveals the direct relation of its skill with the observational accuracy. The skill of AI appears, however, mostly related to the model quality and clear increases of skill can only be expected in coincidence with model upgrades. We have compared FFI and AI in experiments in which either the full system or the atmosphere and ocean were independently initialized. In the former case FFI shows better and longer-lasting improvements, with skillful predictions until month 30. In the initialization of single compartments, the best

Assessment of crown fire initiation and spread models in Mediterranean conifer forests by using data from field and laboratory experiments

Energy Technology Data Exchange (ETDEWEB)

Rodríguez y Silva, F.; Guijarro, M.; Madrigal, J.; Jiménez, E.; Molina, J.R.; Hernando, C.; Vélez, R.; Vega, J.A.

2017-11-01

Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation. Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain. Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model. Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena. Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.

Assessment of crown fire initiation and spread models in Mediterranean conifer forests by using data from field and laboratory experiments

International Nuclear Information System (INIS)

Rodríguez y Silva, F.; Guijarro, M.; Madrigal, J.; Jiménez, E.; Molina, J.R.; Hernando, C.; Vélez, R.; Vega, J.A.

2017-01-01

Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation. Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain. Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model. Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena. Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.

Methods for initial characterization of Campylobacter jejuni bacteriophages

DEFF Research Database (Denmark)

Sørensen, Martine Camilla Holst; Gencay, Yilmaz Emre; Brøndsted, Lone

2017-01-01

Here we describe an initial characterization of Campylobacter jejuni bacteriophages by host range analysis, genome size determination by pulsed-field gel electrophoresis, and receptor-type identification by screening mutants for phage sensitivity.......Here we describe an initial characterization of Campylobacter jejuni bacteriophages by host range analysis, genome size determination by pulsed-field gel electrophoresis, and receptor-type identification by screening mutants for phage sensitivity....

REFIR/BB initial observations in the water vapour rotational band: Results from a field campaign

International Nuclear Information System (INIS)

Esposito, F.; Grieco, G.; Leone, L.; Restieri, R.; Serio, C.; Bianchini, G.; Palchetti, L.; Pellegrini, M.; Cuomo, V.; Masiello, G.; Pavese, G.

2007-01-01

There is a growing interest in the far infrared spectral region 17-50 μm as a remote sensing tool in atmospheric sciences, since this portion of the spectrum contains the characteristic molecular rotational band for water vapour. Much of the Earth energy lost to space is radiated through this spectral region. The Radiation Explorer in the Far InfraRed Breadboard (REFIR/BB) spectrometer was born because of the quest to make observations in the far infrared. REFIR/BB is a Fourier Transform Spectrometer with a sampling resolution of 0.5 cm -1 and it was tested for the first time in the field to check its reliability and radiometric performance. The field campaign was held at Toppo di Castelgrande (40 o 49' N, 15 o 27' E, 1258 m a. s. l.), a mountain site in South Italy. The spectral and radiometric performance of the instrument and initial observations are shown in this paper. Comparisons to both (1) BOMEM MR100 Fourier Transform spectrometer observations and (2) line-by-line radiative transfer calculations for selected clear sky are presented and discussed. These comparisons (1) show a very nice agreement between radiance measured by REFIR/BB and by BOMEM MR100 and (2) demonstrate that REFIR/BB accurately observes the very fine spectral structure in the water vapour rotational band

The impact of nudging coefficient for the initialization on the atmospheric flow field and the photochemical ozone concentration of Seoul, Korea

Science.gov (United States)

Choi, Hyun-Jung; Lee, Hwa Woon; Sung, Kyoung-Hee; Kim, Min-Jung; Kim, Yoo-Keun; Jung, Woo-Sik

In order to incorporate correctly the large or local scale circulation in the model, a nudging term is introduced into the equation of motion. Nudging effects should be included properly in the model to reduce the uncertainties and improve the air flow field. To improve the meteorological components, the nudging coefficient should perform the adequate influence on complex area for the model initialization technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to evaluate the effects on air quality modeling by comparing the performance of the meteorological result with variable nudging coefficient experiment. All experiments are calculated by the upper wind conditions (synoptic or asynoptic condition), respectively. Consequently, it is important to examine the model response to nudging effect of wind and mass information. The MM5-CMAQ model was used to assess the ozone differences in each case, during the episode day in Seoul, Korea and we revealed that there were large differences in the ozone concentration for each run. These results suggest that for the appropriate simulation of large or small-scale circulations, nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, so appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. The statistical verifications showed that adequate nudging coefficient for both wind and temperature data throughout the model had a consistently positive impact on the atmospheric and air quality field. On the case dominated by large-scale circulation, a large nudging coefficient shows a minor improvement in the atmospheric and air quality field. However, when small-scale convection is present, the large nudging coefficient produces consistent improvement in the atmospheric and air quality field.

Preparing beginning reading teachers: An experimental comparison of initial early literacy field experiences.

Science.gov (United States)

Al Otaiba, Stephanie; Lake, Vickie E; Greulich, Luana; Folsom, Jessica S; Guidry, Lisa

2012-01-01

This randomized-control trial examined the learning of preservice teachers taking an initial Early Literacy course in an early childhood education program and of the kindergarten or first grade students they tutored in their field experience. Preservice teachers were randomly assigned to one of two tutoring programs: Book Buddies and Tutor Assisted Intensive Learning Strategies (TAILS), which provided identical meaning-focused instruction (shared book reading), but differed in the presentation of code-focused skills. TAILS used explicit, scripted lessons, and the Book Buddies required that code-focused instruction take place during shared book reading. Our research goal was to understand which tutoring program would be most effective in improving knowledge about reading, lead to broad and deep language and preparedness of the novice preservice teachers, and yield the most successful student reading outcomes. Findings indicate that all pre-service teachers demonstrated similar gains in knowledge, but preservice teachers in the TAILS program demonstrated broader and deeper application of knowledge and higher self-ratings of preparedness to teach reading. Students in both conditions made similar comprehension gains, but students tutored with TAILS showed significantly stronger decoding gains.

Initial value formulation of higher derivative gravity

International Nuclear Information System (INIS)

Noakes, D.R.

1983-01-01

The initial value problem is considered for the conformally coupled scalar field and higher derivative gravity, by expressing the equations of each theory in harmonic coordinates. For each theory it is shown that the (vacuum) equations can take the form of a diagonal hyperbolic system with constraints on the initial data. Consequently these theories possess well-posed initial value formulations

Quantum interference induced by initial system–environment correlations

International Nuclear Information System (INIS)

Man, Zhong-Xiao; Smirne, Andrea; Xia, Yun-Jie; Vacchini, Bassano

2012-01-01

We investigate the quantum interference induced by a relative phase in the correlated initial state of a system which consists in a two-level atom interacting with a damped mode of the radiation field. We show that the initial relative phase has significant effects on both the evolution of the atomic excited-state population and the information flow between the atom and the reservoir, as quantified by the trace distance. Furthermore, by considering two two-level atoms interacting with a common damped mode of the radiation field, we highlight how initial relative phases can affect the subsequent entanglement dynamics. -- Highlights: ► We study the effect of initial correlations in system–bath excitation transfer. ► We study the information flow from the bath to the system via the trace distance. ► We show how entanglement dynamics can be controlled via initial relative phases.

Initial results from the TST-2 spherical tokamak

International Nuclear Information System (INIS)

Takase, Y.; Ejiri, A.; Kasuya, N.

2001-01-01

A new spherical tokamak TST-2 was constructed at the University of Tokyo and started operation in September 1999. Reliable plasma initiation is achieved with typically 1 kW of ECH power at 2.45 GHz. Plasma currents of up to 90 kA and toroidal fields of up to 0.2 T have been achieved during the initial experimental campaign. The ion temperature is typically 100 eV. Internal reconnection events (IREs) are often observed. The internal magnetic field measured at r/a=2/3 indicated growth of fluctuations up to the 4 th harmonic, suggesting the existence of modes with several different mode numbers. In the presence of a toroidal field and a vertically oriented mirror field, noninductively driven currents of order 1 kA were observed with 1 kW of ECH power. The driven current increased with decreasing filling pressure, down to 3x10 -6 torr. A study of high harmonic fast wave (HHFW) excitation and propagation has begun. Initial results indicate highly efficient wave launching. (author)

Trapped field recovery of bulk superconductor magnets by static field magnetization

Science.gov (United States)

Deng, Z.; Tsuzuki, K.; Miki, M.; Felder, B.; Hara, S.; Izumi, M.

2011-11-01

Thanks to the trapped field of bulk high-temperature superconductors, they can be used as field-pole magnets in the high temperature superconducting (HTS) rotating machines. For example, an output power of 10 kW at 720 rpm was realized by an average trapped field of 0.56 T of eight melt-textured GdBa2Cu3Oy (Gd-123) bulks at liquid nitrogen temperature in TUMSAT in 2004. Similarly to the HTS machines involving 1G or 2G wires, the trapped field of the bulk is possibly sensitive and even can be attenuated by the AC component field during the operation. Hence, it is necessary to recover the trapped field once being decreased to some extent in the practical application. From this point, we have investigated the trapped field recovery of HTS bulk magnets by static field magnetization in the paper. A series of different initial trapped fields after zero-field-cooling or field-cooling magnetization are used to simulate the attenuated trapped field. By comparing the trapped field peak and its distribution, the trapped field was found to be able to recover by the static field magnetization method with a stronger excitation field and the initial trapped flux inside the bulk also has an influence on the recovery process. The optimum recovery field was found to be about 2.5 times the saturated trapped field of the bulk at liquid nitrogen temperature, by which the bulk can regain the former best trapped field performance.

What is Happening in the Petišovci Fields? An Edited Conversation with an Activist of the Initiative “Stop the Fracking in Slovenia”

Directory of Open Access Journals (Sweden)

Danijela Tamše

2015-12-01

Full Text Available The article is an edited conversation with an activist of an initiative “Stop the fracking in Slovenia”. In order to start the process of fracking for natural gas extraction in the Prekmurje region, companies still have to obtain some environmental permits from the government environmental agency, which seems to have taken the companies’ side. The initiative is struggling to stop this. The conversation was focused on the developments in the Petišovci fields, formal procedures connected to obtaining permits, and the companies involved. The article also contains the explanation of what fracking is.

Toluene removal from sandy soils via in situ technologies with an emphasis on factors influencing soil vapor extraction.

Science.gov (United States)

Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

2014-01-01

The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

Directory of Open Access Journals (Sweden)

Mohammad Mehdi Amin

2014-01-01

Full Text Available The integration of bioventing (BV and soil vapor extraction (SVE appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5% of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

Initiating a New Research Phase in the Field of International Entrepreneurship

DEFF Research Database (Denmark)

Coviello, Nicole; Tanev, Stoyan

2017-01-01

In a recent publication, Nicole Coviello (2015) emphasized the need to re-think existing research on international entrepreneurship and, more specifically, research on born-global firms. She pointed out that the main value of a critical review lies in initiating a new research phase focusing on t...... be of relevance for new technology firms aiming at an international or global engagement from their very inception.......In a recent publication, Nicole Coviello (2015) emphasized the need to re-think existing research on international entrepreneurship and, more specifically, research on born-global firms. She pointed out that the main value of a critical review lies in initiating a new research phase focusing...

New method for initial density reconstruction

Science.gov (United States)

Shi, Yanlong; Cautun, Marius; Li, Baojiu

2018-01-01

A theoretically interesting and practically important question in cosmology is the reconstruction of the initial density distribution provided a late-time density field. This is a long-standing question with a revived interest recently, especially in the context of optimally extracting the baryonic acoustic oscillation (BAO) signals from observed galaxy distributions. We present a new efficient method to carry out this reconstruction, which is based on numerical solutions to the nonlinear partial differential equation that governs the mapping between the initial Lagrangian and final Eulerian coordinates of particles in evolved density fields. This is motivated by numerical simulations of the quartic Galileon gravity model, which has similar equations that can be solved effectively by multigrid Gauss-Seidel relaxation. The method is based on mass conservation, and does not assume any specific cosmological model. Our test shows that it has a performance comparable to that of state-of-the-art algorithms that were very recently put forward in the literature, with the reconstructed density field over ˜80 % (50%) correlated with the initial condition at k ≲0.6 h /Mpc (1.0 h /Mpc ). With an example, we demonstrate that this method can significantly improve the accuracy of BAO reconstruction.

Chaotic inflation as an attractor in initial-condition space

International Nuclear Information System (INIS)

Kung, J.H.; Brandenberger, R.H.

1990-01-01

We study the evolution of scalar field inhomogeneities in the preinflationary phase of an inflationary universe. We decompose the scalar field configuration in Fourier modes and consider initial conditions in which more than one mode is excited. We find that the long-wavelength modes are stable against perturbations due to short-wavelength excitations and that chaotic inflation results even if at the initial time the short waves contain most of the energy density

Effect of intervention initiation timing of pulsed electromagnetic field on ovariectomy-induced osteoporosis in rats.

Science.gov (United States)

Zhou, Jun; Liao, Yuan; Zeng, Yahua; Xie, Haitao; Fu, Chengxiao; Li, Neng

2017-09-01

The aim of this study is to explore the effect of timing of initiation of pulsed electromagnetic field (PEMF) therapy on bone mass, microarchitecture, and biomechanical properties, and to investigate receptor activator of NF-kB (RANK) expression in ovariectomized (OVX) rats. Sixty female Sprague-Dawley rats were randomly divided into two equal batches of three groups each (10 rats in each group). The first batch comprised of sham-operated (Sham-0 group), ovariectomized (OVX-0 group), and ovariectomized plus treated with PEMF starting from the day of OVX (Early PEMF group). The second batch comprised of sham-operated (Sham-12 group), ovariectomized (OVX-12 group), and ovariectomized plus treated with PEMF starting 12 weeks after OVX (Late PEMF group). Rats (whole body) in the early and late PEMF groups were exposed to PEMF (3.8 mT peak, 8 Hz pulse burst repetition rate). After 12 weeks of PEMF therapy, Early PEMF prevented OVX-induced deterioration in bone mineral density (BMD) and mechanical properties in lumbar vertebral body and femur, and deterioration in bone microarchitecture in lumbar vertebral body and proximal tibia. Late PEMF intervention only inhibited deterioration of BMD, bone microarchitecture, and mechanical properties in lumbar vertebral body. Both early and late PEMF therapy suppressed RANK protein expression in OVX rats without a concomitant effect on RANK mRNA expression. These results demonstrate that timing of initiation of PEMF therapy plays an important role in achieving optimal beneficial effects. The specific PEMF parameters may exert these favorable biological responses, at least partially, via inhibition of protein expression of RANK. Bioelectromagnetics. 38:456-465, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Behavior of pentacene initial nucleation on various dielectrics and its effect on carrier transport in organic field-effect transistor.

Science.gov (United States)

Qi, Qiong; Yu, Aifang; Wang, Liangmin; Jiang, Chao

2010-11-01

The influence of dielectric surface energy on the initial nucleation and the growth of pentacene films as well as the electrical properties of the pentacene-based field-effect transistors are investigated. We have examined a range of organic and inorganic dielectrics with different surface energies, such as polycarbonate/SiO2, polystyrene/SiO2, and PMMA/SiO2 bi-layered dielectrics and also the bare SiO2 dielectric. Atomic force microscopy measurements of sub-monolayer and thick pentacene films indicated that the growth of pentacene film was in Stranski-Kranstanow growth mode on all the dielectrics. However, the initial nucleation density and the size of the first-layered pentacene islands deposited on different dielectrics are drastically influenced by the dielectric surface energy. With the increasing of the surface energy, the nucleation density increased and thus the average size of pentacene islands for the first mono-layer deposition decreased. The performance of fabricated pentacene-based thin film transistors was found to be highly related to nucleation density and the island size of deposited Pentacene film, and it had no relationship to the final particle size of the thick pentacene film. The field effect mobility of the thin film transistor could be achieved as high as 1.38 cm2Ns with on/off ratio over 3 x 10(7) on the PS/SiO2 where the lowest surface energy existed among all the dielectrics. For comparison, the values of mobility and on/off ratio were 0.42 cm2Ns and 1 x 10(6) for thin film transistor deposited directly on bare SiO2 having the highest surface energy.

Alaska North Slope National Energy Strategy initiative: Analysis of five undeveloped fields

International Nuclear Information System (INIS)

Thomas, C.P.; Allaire, R.B.; Doughty, T.C.; Faulder, D.D.; Irving, J.S.; Jamison, H.C.; White, G.J.

1993-05-01

The US Department of Energy was directed in the National Energy Strategy to establish a federal interagency task force to identify specific technical and regulatory barriers to the development of five undeveloped North Slope Alaska fields and make recommendations for their resolution. The five fields are West Sak, Point Thomson, Gwydyr Bay, Seal Island/Northstar, and Sandpiper Island. Analysis of environmental, regulatory, technical, and economic information, and data relating to the development potential of the five fields leads to the following conclusions: Development of the five fields would result in an estimated total of 1,055 million barrels of oil and 4.4 trillion cubic feet of natural gas and total investment of $9.4 billion in 1992 dollars. It appears that all five of the fields will remain economically marginal developments unless there is significant improvement in world oil prices. Costs of regulatory compliance and mitigation, and costs to reduce or maintain environmental impacts at acceptable levels influence project investments and operating costs and must be considered in the development decision making process. The development of three of the fields (West Sak, Point Thomson, and Gwydyr Bay) that are marginally feasible would have an impact on North Slope production over the period from about 2000 to 2014 but cannot replace the decline in Prudhoe Bay Unit production or maintain the operation of the Trans-Alaska Pipeline System (TAPS) beyond about 2014 with the assumption that the TAPS will shut down when production declines to the range of 400 to 200 thousand barrels of oil/day. Recoverable reserves left in the ground in the currently producing fields and soon to be developed fields, Niakuk and Point McIntyre, would range from 1 billion to 500 million barrels of oil corresponding to the time period of 2008 to 2014 based on the TAPS shutdown assumption

Alaska North Slope National Energy Strategy initiative: Analysis of five undeveloped fields

Energy Technology Data Exchange (ETDEWEB)

Thomas, C.P.; Allaire, R.B.; Doughty, T.C.; Faulder, D.D.; Irving, J.S.; Jamison, H.C.; White, G.J.

1993-05-01

The US Department of Energy was directed in the National Energy Strategy to establish a federal interagency task force to identify specific technical and regulatory barriers to the development of five undeveloped North Slope Alaska fields and make recommendations for their resolution. The five fields are West Sak, Point Thomson, Gwydyr Bay, Seal Island/Northstar, and Sandpiper Island. Analysis of environmental, regulatory, technical, and economic information, and data relating to the development potential of the five fields leads to the following conclusions: Development of the five fields would result in an estimated total of 1,055 million barrels of oil and 4.4 trillion cubic feet of natural gas and total investment of $9.4 billion in 1992 dollars. It appears that all five of the fields will remain economically marginal developments unless there is significant improvement in world oil prices. Costs of regulatory compliance and mitigation, and costs to reduce or maintain environmental impacts at acceptable levels influence project investments and operating costs and must be considered in the development decision making process. The development of three of the fields (West Sak, Point Thomson, and Gwydyr Bay) that are marginally feasible would have an impact on North Slope production over the period from about 2000 to 2014 but cannot replace the decline in Prudhoe Bay Unit production or maintain the operation of the Trans-Alaska Pipeline System (TAPS) beyond about 2014 with the assumption that the TAPS will shut down when production declines to the range of 400 to 200 thousand barrels of oil/day. Recoverable reserves left in the ground in the currently producing fields and soon to be developed fields, Niakuk and Point McIntyre, would range from 1 billion to 500 million barrels of oil corresponding to the time period of 2008 to 2014 based on the TAPS shutdown assumption.

Evolution of the Orszag-Tang vortex system in a compressible medium. I - Initial average subsonic flow

Science.gov (United States)

Dahlburg, R. B.; Picone, J. M.

1989-01-01

The results of fully compressible, Fourier collocation, numerical simulations of the Orszag-Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2-0.6. These values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.

A prototype tap test imaging system: Initial field test results

Science.gov (United States)

Peters, J. J.; Barnard, D. J.; Hudelson, N. A.; Simpson, T. S.; Hsu, D. K.

2000-05-01

This paper describes a simple, field-worthy tap test imaging system that gives quantitative information about the size, shape, and severity of defects and damages. The system consists of an accelerometer, electronic circuits for conditioning the signal and measuring the impact duration, a laptop PC and data acquisition and processing software. The images are generated manually by tapping on a grid printed on a plastic sheet laid over the part's surface. A mechanized scanner is currently under development. The prototype has produced images for a variety of aircraft composite and metal honeycomb structures containing flaws, damages, and repairs. Images of the local contact stiffness, deduced from the impact duration using a spring model, revealed quantitatively the stiffness reduction due to flaws and damages, as well as the stiffness enhancement due to substructures. The system has been field tested on commercial and military aircraft as well as rotor blades and engine decks on helicopters. Field test results will be shown and the operation of the system will be demonstrated.—This material is based upon work supported by the Federal Aviation Administration under Contract #DTFA03-98-D-00008, Delivery Order No. IA016 and performed at Iowa State University's Center for NDE as part of the Center for Aviation Systems Reliability program.

Initial value problem for plasma oscillations

International Nuclear Information System (INIS)

Li, J.; Spies, G.O.

1991-01-01

The solution of the initial value problem for the linearized one-dimensional electron Vlasov--Poisson equations in a field-free homogeneous equilibrium is examined for small and for large ratios κ of Debye length and wavelength, assuming initial perturbing distribution functions varying on the same velocity scale as the equilibrium. Previously known approximations of the initial evolution (which, unlike the time-asymptotic one, does not depend on analyticity assumptions) are extended to longer times, and to arbitrary stable or unstable equilibria: In the quasifluid regime (small κ), the electric field, within an additive error O(κ 2 ), and independently of the initial data, performs an oscillation near the plasma frequency that corresponds to an eigenmode if it is unstable or marginal, but to an approximate eigenmode arising from the continuous spectrum otherwise. If other unstable or marginal modes are present, these influence only the time-asymptotic behavior because their amplitudes are O(κ 2 ) initially. In the ballistic regime (large κ), there are no instabilities and the perturbing density, now within an error O(κ -2 ), is the Fourier transform of the initial perturbing distribution function, thus following an arbitrary decay law that is independent of the equilibrium. The errors are shown to be time-independent, implying that either approximation is relevant at least until the perturbing density has essentially damped out. Hence the dominating damping mechanism (in the stable case) is Landau damping if κ much-lt 1, but ballistic particle mixing if κ much-gt 1

Gibbs perturbations of a two-dimensional gauge field

International Nuclear Information System (INIS)

Petrova, E.N.

1981-01-01

Small Gibbs perturbations of random fields have been investigated up to now for a few initial fields only. Among them there are independent fields, Gaussian fields and some others. The possibility for the investigation of Gibbs modifications of a random field depends essentially on the existence of good estimates for semiinvariants of this field. This is the reason why the class of random fields for which the investigation of Gibbs perturbations with arbitrary potential of bounded support is possible is rather small. The author takes as initial a well-known model: a two-dimensional gauge field. (Auth.)

Initial state with shear in peripheral heavy ion collisions

Science.gov (United States)

Magas, V. K.; Gordillo, J.; Strottman, D.; Xie, Y. L.; Csernai, L. P.

2018-06-01

In the present work we propose a new way of constructing the initial state for further hydrodynamic simulation of relativistic heavy ion collisions based on Bjorken-like solution applied streak by streak in the transverse plane. Previous fluid dynamical calculations in Cartesian coordinates with an initial state based on a streak by streak Yang-Mills field led for peripheral higher energy collisions to large angular momentum, initial shear flow and significant local vorticity. Recent experiments verified the existence of this vorticity via the resulting polarization of emitted Λ and Λ ¯ particles. At the same time parton cascade models indicated the existence of more compact initial state configurations, which we are going to simulate in our approach. The proposed model satisfies all the conservation laws, including conservation of a strong initial angular momentum, which is present in noncentral collisions. As a consequence of this large initial angular momentum we observe the rotation of the whole system as well as the fluid shear in the initial state, which leads to large flow vorticity. Another advantage of the proposed model is that the initial state can be given in both [t,x,y,z] and [τ ,x ,y ,η ] coordinates and thus can be tested by all 3+1D hydrodynamical codes which exist in the field.

Polyhomogeneous expansions from time symmetric initial data

Science.gov (United States)

Gasperín, E.; Valiente Kroon, J. A.

2017-10-01

We make use of Friedrich’s construction of the cylinder at spatial infinity to relate the logarithmic terms appearing in asymptotic expansions of components of the Weyl tensor to the freely specifiable parts of time symmetric initial data sets for the Einstein field equations. Our analysis is based on the assumption that a particular type of formal expansions near the cylinder at spatial infinity corresponds to the leading terms of actual solutions to the Einstein field equations. In particular, we show that if the Bach tensor of the initial conformal metric does not vanish at the point at infinity then the most singular component of the Weyl tensor decays near null infinity as O(\\tilde{r}-3\\ln \\tilde{r}) so that spacetime will not peel. We also provide necessary conditions on the initial data which should lead to a peeling spacetime. Finally, we show how to construct global spacetimes which are candidates for non-peeling (polyhomogeneous) asymptotics.

Tripolar electric field Structure in guide field magnetic reconnection

Science.gov (United States)

Fu, Song; Huang, Shiyong; Zhou, Meng; Ni, Binbin; Deng, Xiaohua

2018-03-01

It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

Tripolar electric field Structure in guide field magnetic reconnection

Directory of Open Access Journals (Sweden)

S. Fu

2018-03-01

Full Text Available It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection. In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg. Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Tyburski, J.R.

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application

On the study of the magnetic domain pattern via the initial magnetization curve

International Nuclear Information System (INIS)

Wu, T.

1997-01-01

This study inquires into the relationships between the initial magnetization curve and the magnetic domain pattern in the demagnetized states for amorphous TbFeCo as well as multilayered Co/Pd thin film samples. This was done specifically through an investigation of different demagnetized states of samples demagnetized by a variety of methods. The magnetic domain pattern for the sample demagnetized by an in-plane magnetic field and for the sample demagnetized by a perpendicular magnetic field was found to be quite different even though both states have zero magnetization. The former state has denser and finer domains than the latter. In addition, both states were studied in light of the initial magnetization curves obtained by measurements of the magneto-optic Kerr effect and the extraordinary Hall effect. Moreover, the initial magnetization for the fine domains increases with an increase in magnetic field, while for the coarse domains, the initial magnetization remains at zero for magnetic field below coercivity H c , then rises sharply to saturated magnetization when magnetic field is nearly equal to H c . copyright 1997 American Institute of Physics

Lightning-Discharge Initiation as a Noise-Induced Kinetic Transition

Science.gov (United States)

Iudin, D. I.

2017-10-01

The electric fields observed in thunderclouds have the peak values one order of magnitude smaller than the electric strength of air. This fact renders the issue of the lightning-discharge initiation one of the most intriguing problems of thunderstorm electricity. In this work, the lightning initiation in a thundercloud is considered as a noise-induced kinetic transition. The stochastic electric field of the charged hydrometeors is the noise source. The considered kinetic transition has some features which distinguish it from other lightning-initiation mechanisms. First, the dynamic realization of this transition, which is due to interaction of the electron and ion components, is extended for a time significantly exceeding the spark-discharge development time. In this case, the fast attachment of electrons generated by supercritical bursts of the electric field of hydrometeors is balanced during long-term time intervals by the electron-release processes when the negative ions are destroyed. Second, an important role in the transition kinetics is played by the stochastic drift of electrons and ions caused by the small-scale fluctuations of the field of charged hydrometeors. From the formal mathematical viewpoint, this stochastic drift is indistinguishable from the scalar-impurity advection in a turbulent flow. In this work, it is shown that the efficiency of "advective mixing" is several orders of magnitude greater than that of the ordinary diffusion. Third, the considered transition leads to a sharp increase in the conductivity in the exponentially rare compact regions of space against the background of the vanishingly small variations in the average conductivity of the medium. In turn, the spots with increased conductivity are polarized in the mean field followed by the streamer initiation and discharge contraction.

Magnetic Field Topology in Jets

Science.gov (United States)

Gardiner, T. A.; Frank, A.

2000-01-01

We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

Lower Crustal Seismicity, Volatiles, and Evolving Strain Fields During the Initial Stages of Cratonic Rifting

Science.gov (United States)

Lambert, C.; Muirhead, J.; Ebinger, C. J.; Tiberi, C.; Roecker, S. W.; Ferdinand-Wambura, R.; Kianji, G.; Mulibo, G. D.

2014-12-01

The volcanically active East African rift system in southern Kenya and northern Tanzania transects thick cratonic lithosphere, and comprises several basins characterized by deep crustal seismicity. The US-French-Tanzania-Kenya CRAFTI project aims to understand the role of magma and volatile movement during the initiation and evolution of rifting in cratonic lithosphere. Our 38-station broadband network spans all or parts of fault-bounded rift segments, enabling comparison of lithospheric structure, fault kinematics, and seismogenic layer thickness with age and proximity to the deeply rooted Archaen craton. Seismicity levels are high in all basins, but we find profound differences in seismogenic layer thickness along the length of the rift. Seismicity in the Manyara basin occurs almost exclusively within the lower crust, and in spatial clusters that have been active since 1990. In contrast, seismicity in the ~ 5 My older Magadi basin is localized in the upper crust, and the long border fault bounding the west side of the basin is seismically inactive. Between these two basins lies the Natron rift segment, which shows seismicity between ~ 20 and ~2 km depth, and high concentrations at Oldoinyo Lengai and Gelai volcanoes. Older volcanoes on the uplifted western flank (e.g., Ngorongoro) experience swarms of activity, suggesting that active magmatism and degassing are widespread. Focal mechanisms of the frequent earthquakes recorded across the array are spatially variable, and indicate a stress field strongly influenced by (1) Holocene volcanoes, (2) mechanical interactions between adjacent rift basins, and (3) a far-field ESE-WNW extensional stress regime. We explore the spatial correlation between zones of intense degassing along fault systems and seismicity, and examine the influence of high gas pressures on lower and upper crustal seismicity in this youthful cratonic rift zone.

Initial study - compilation and synthesis of knowledge about energy crops from field to energy production

Energy Technology Data Exchange (ETDEWEB)

Berg, Magnus; Bubholz, Monika; Forsberg, Maya; Myringer, Aase; Palm, Ola; Roennbaeck, Marie; Tullin, Claes

2007-11-15

Energy crops constitute an yet not fully utilised potential as fuel for heating and power production. As competition for biomass increases interest in agricultural fuels such as straw, energy grain, willow, reed canary grass and hemp is increasing. Exploiting the potential for energy crops as fuels will demand that cultivation and harvest be coordinated with transportation, storage and combustion of the crops. Together, Vaermeforsk and the Swedish Farmers' Foundation for Agricultural Research (SLF), have taken the initiative to a common research programme. The long-term aim of the programme is to increase production and utilisation of bioenergy from agriculture to combustion for heat and power production in Sweden. The vision is that during the course of the 2006 - 2009 programme, decisive steps will be taken towards a functioning market for biofuels for bioenergy from agriculture. This survey has compiled and synthesised available knowledge and experiences about energy crops from field to energy production. The aim has been to provide a snapshot of knowledge today, to identify knowledge gaps and to synthesise knowledge we have today into future research needs. A research plan proposal has been developed for the research programme

Multipoint propagators for non-Gaussian initial conditions

International Nuclear Information System (INIS)

Bernardeau, Francis; Sefusatti, Emiliano; Crocce, Martin

2010-01-01

We show here how renormalized perturbation theory calculations applied to the quasilinear growth of the large-scale structure can be carried on in presence of primordial non-Gaussian (PNG) initial conditions. It is explicitly demonstrated that the series reordering scheme proposed in Bernardeau, Crocce, and Scoccimarro [Phys. Rev. D 78, 103521 (2008)] is preserved for non-Gaussian initial conditions. This scheme applies to the power spectrum and higher-order spectra and is based on a reorganization of the contributing terms into the sum of products of multipoint propagators. In case of PNG, new contributing terms appear, the importance of which is discussed in the context of current PNG models. The properties of the building blocks of such resummation schemes, the multipoint propagators, are then investigated. It is first remarked that their expressions are left unchanged at one-loop order irrespective of statistical properties of the initial field. We furthermore show that the high-momentum limit of each of these propagators can be explicitly computed even for arbitrary initial conditions. They are found to be damped by an exponential cutoff whose expression is directly related to the moment generating function of the one-dimensional displacement field. This extends what had been established for multipoint propagators for Gaussian initial conditions. Numerical forms of the cutoff are shown for the so-called local model of PNG.

Solutions to the Cosmic Initial Entropy Problem without Equilibrium Initial Conditions

Directory of Open Access Journals (Sweden)

Vihan M. Patel

2017-08-01

Full Text Available The entropy of the observable universe is increasing. Thus, at earlier times the entropy was lower. However, the cosmic microwave background radiation reveals an apparently high entropy universe close to thermal and chemical equilibrium. A two-part solution to this cosmic initial entropy problem is proposed. Following Penrose, we argue that the evenly distributed matter of the early universe is equivalent to low gravitational entropy. There are two competing explanations for how this initial low gravitational entropy comes about. (1 Inflation and baryogenesis produce a virtually homogeneous distribution of matter with a low gravitational entropy. (2 Dissatisfied with explaining a low gravitational entropy as the product of a ‘special’ scalar field, some theorists argue (following Boltzmann for a “more natural” initial condition in which the entire universe is in an initial equilibrium state of maximum entropy. In this equilibrium model, our observable universe is an unusual low entropy fluctuation embedded in a high entropy universe. The anthropic principle and the fluctuation theorem suggest that this low entropy region should be as small as possible and have as large an entropy as possible, consistent with our existence. However, our low entropy universe is much larger than needed to produce observers, and we see no evidence for an embedding in a higher entropy background. The initial conditions of inflationary models are as natural as the equilibrium background favored by many theorists.

Bioremediation at a petroleum refinery

International Nuclear Information System (INIS)

Carson, A.W.; Jarvis, J.; Richardson, K.E.

1994-01-01

This paper presents a summary of three projects at the Mobil Refinery in Torrance, California where bioremediation technologies were successfully employed for the remediation of hydrocarbon contaminated soil. The three projects represent variations of implementation of bioremediation, both in-situ and ex-situ. Soil from all of the projects was considered non-hazardous designated waste under the California Code of Regulations, Title 23, section 2522. The projects were permitted and cleanup requirements were defined with the Los Angeles Regional Water Quality Control Board. In all of the projects, different methods were used for supplying water, oxygen, and nutrients to the hydrocarbon degrading bacteria to stimulate growth. The Stormwater Retention Basin Project utilized in-situ mechanical mixing of soils to supply solid nutrients and oxygen, and a self-propelled irrigation system to supply water. The Tank Farm Lake project used an in-situ active bioventing technology to introduce oxygen, moisture, and vapor phase nutrients. The Tank 1340X247 project was an ex-situ bioventing remediation project using a drip irrigation system to supply water and dissolved nutrients, and a vapor extraction system to provide oxygen

Initial value formulation of dynamical Chern-Simons gravity

Science.gov (United States)

Delsate, Térence; Hilditch, David; Witek, Helvi

2015-01-01

We derive an initial value formulation for dynamical Chern-Simons gravity, a modification of general relativity involving parity-violating higher derivative terms. We investigate the structure of the resulting system of partial differential equations thinking about linearization around arbitrary backgrounds. This type of consideration is necessary if we are to establish well-posedness of the Cauchy problem. Treating the field equations as an effective field theory we find that weak necessary conditions for hyperbolicity are satisfied. For the full field equations we find that there are states from which subsequent evolution is not determined. Generically the evolution system closes, but is not hyperbolic in any sense that requires a first order pseudodifferential reduction. In a cursory mode analysis we find that the equations of motion contain terms that may cause ill-posedness of the initial value problem.

Space Technology 5 Multi-point Measurements of Near-Earth Magnetic Fields: Initial Results

Science.gov (United States)

Slavin, James A.; Le, G.; Strangeway, R. L.; Wang, Y.; Boardsen, S.A.; Moldwin, M. B.; Spence, H. E.

2007-01-01

The Space Technology 5 (ST-5) mission successfully placed three micro-satellites in a 300 x 4500 km dawn-dusk orbit on 22 March 2006. Each spacecraft carried a boom-mounted vector fluxgate magnetometer that returned highly sensitive and accurate measurements of the geomagnetic field. These data allow, for the first time, the separation of temporal and spatial variations in field-aligned current (FAC) perturbations measured in low-Earth orbit on time scales of approximately 10 sec to 10 min. The constellation measurements are used to directly determine field-aligned current sheet motion, thickness and current density. In doing so, we demonstrate two multi-point methods for the inference of FAC current density that have not previously been possible in low-Earth orbit; 1) the "standard method," based upon s/c velocity, but corrected for FAC current sheet motion, and 2) the "gradiometer method" which uses simultaneous magnetic field measurements at two points with known separation. Future studies will apply these methods to the entire ST-5 data set and expand to include geomagnetic field gradient analyses as well as field-aligned and ionospheric currents.

Predicting the susceptibility to gully initiation in data-poor regions

Science.gov (United States)

Dewitte, Olivier; Daoudi, Mohamed; Bosco, Claudio; Van Den Eeckhaut, Miet

2015-01-01

Permanent gullies are common features in many landscapes and quite often they represent the dominant soil erosion process. Once a gully has initiated, field evidence shows that gully channel formation and headcut migration rapidly occur. In order to prevent the undesired effects of gullying, there is a need to predict the places where new gullies might initiate. From detailed field measurements, studies have demonstrated strong inverse relationships between slope gradient of the soil surface (S) and drainage area (A) at the point of channel initiation across catchments in different climatic and morphological environments. Such slope-area thresholds (S-A) can be used to predict locations in the landscape where gullies might initiate. However, acquiring S-A requires detailed field investigations and accurate high resolution digital elevation data, which are usually difficult to acquire. To circumvent this issue, we propose a two-step method that uses published S-A thresholds and a logistic regression analysis (LR). S-A thresholds from the literature are used as proxies of field measurement. The method is calibrated and validated on a watershed, close to the town of Algiers, northern Algeria, where gully erosion affects most of the slopes. The gullies extend up to several kilometres in length and cover 16% of the study area. First we reconstruct the initiation areas of the existing gullies by applying S-A thresholds for similar environments. Then, using the initiation area map as the dependent variable with combinations of topographic and lithological predictor variables, we calibrate several LR models. It provides relevant results in terms of statistical reliability, prediction performance, and geomorphological significance. This method using S-A thresholds with data-driven assessment methods like LR proves to be efficient when applied to common spatial data and establishes a methodology that will allow similar studies to be undertaken elsewhere.

Influence of changes in initial conditions for the simulation of dynamic systems

Energy Technology Data Exchange (ETDEWEB)

Kotyrba, Martin [Department of Informatics and Computers, University of Ostrava, 30 dubna 22, Ostrava (Czech Republic)

2015-03-10

Chaos theory is a field of study in mathematics, with applications in several disciplines including meteorology, sociology, physics, engineering, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions—a paradigm popularly referred to as the butterfly effect. Small differences in initial conditions field widely diverging outcomes for such dynamical systems, rendering long-term prediction impossible in general. This happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved. In this paperinfluence of changes in initial conditions will be presented for the simulation of Lorenz system.

Theoretical and numerical studies of crack initiation and propagation in rock masses under freezing pressure and far-field stress

Directory of Open Access Journals (Sweden)

Yongshui Kang

2014-10-01

Full Text Available Water-bearing rocks exposed to freezing temperature can be subjected to freeze–thaw cycles leading to crack initiation and propagation, which are the main causes of frost damage to rocks. Based on the Griffith theory of brittle fracture mechanics, the crack initiation criterion, propagation direction, and crack length under freezing pressure and far-field stress are analyzed. Furthermore, a calculation method is proposed for the stress intensity factor (SIF of the crack tip under non-uniformly distributed freezing pressure. The formulae for the crack/fracture propagation direction and length of the wing crack under freezing pressure are obtained, and the mechanism for coalescence of adjacent cracks is investigated. In addition, the necessary conditions for different coalescence modes of cracks are studied. Using the topology theory, a new algorithm for frost crack propagation is proposed, which has the capability to define the crack growth path and identify and update the cracked elements. A model that incorporates multiple cracks is built by ANSYS and then imported into FLAC3D. The SIFs are then calculated using a FISH procedure, and the growth path of the freezing cracks after several calculation steps is demonstrated using the new algorithm. The proposed method can be applied to rocks containing fillings such as detritus and slurry.

Aquarius: The Instrument and Initial Results

Science.gov (United States)

Vine, David M Le; Lagerloef, G.S.E.; Ruf, C.; Wentz, F.; Yueh, S.; Piepmeier, J.; Lindstrom, E.; Dinnat, E.

2012-01-01

Aquarius was launched on June 10, 2011 aboard the Aquarius/SAC-D observatory and the instrument has been operating continuously since the initial turned-on was completed on August 25. The initial observed antenna temperatures were close to predicted and the first salinity map was released in September. In order to map the ocean salinity field, Aquarius includes several special features such as the inclusion of a scatterometer to provide a roughness correction, measurement of the third Stokes parameter to correct for Faraday rotation, and fast sampling to mitigate the effects of RFI. This paper provides an overview of the instrument and an example of initial results. Details are covered in subsequent papers in the session on Aquarius

Short initial length quench on CICC of ITER TF coils

Energy Technology Data Exchange (ETDEWEB)

Nicollet, S.; Ciazynski, D.; Duchateau, J.-L.; Lacroix, B. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Bessette, D.; Rodriguez-Mateos, F. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Coatanea-Gouachet, M. [ELC Engineering, 350 chemin du Verladet, F-13290 Les Milles (France); Gauthier, F. [Soditech Ingenierie, 4 bis allée des Gabians, ZI La Frayère, 06150 Cannes (France)

2014-01-29

Previous quench studies performed for the International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) Coils have led to identify two extreme families of quench: first 'severe' quenches over long initial lengths in high magnetic field, and second smooth quenches over short initial lengths in low field region. Detailed analyses and results on smooth quench propagation and detectability on one TF Cable In Conduit Conductor (CICC) with a lower propagation velocity are presented here. The influence of the initial quench energy is shown and results of computations with either a Fast Discharge (FD) of the magnet or without (failure of the voltage quench detection system) are reported. The influence of the central spiral of the conductor on the propagation velocity is also detailed. In the cases of a regularly triggered FD, the hot spot temperature criterion of 150 K (with helium and jacket) is fulfilled for an initial quench length of 1 m, whereas this criterion is exceed (Tmax ≈ 200 K) for an extremely short length of 5 cm. These analyses were carried out using both the Supermagnet(trade mark, serif) and Venecia codes and the comparisons of the results are also discussed.

Short initial length quench on CICC of ITER TF coils

International Nuclear Information System (INIS)

Nicollet, S.; Ciazynski, D.; Duchateau, J.-L.; Lacroix, B.; Bessette, D.; Rodriguez-Mateos, F.; Coatanea-Gouachet, M.; Gauthier, F.

2014-01-01

Previous quench studies performed for the International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) Coils have led to identify two extreme families of quench: first 'severe' quenches over long initial lengths in high magnetic field, and second smooth quenches over short initial lengths in low field region. Detailed analyses and results on smooth quench propagation and detectability on one TF Cable In Conduit Conductor (CICC) with a lower propagation velocity are presented here. The influence of the initial quench energy is shown and results of computations with either a Fast Discharge (FD) of the magnet or without (failure of the voltage quench detection system) are reported. The influence of the central spiral of the conductor on the propagation velocity is also detailed. In the cases of a regularly triggered FD, the hot spot temperature criterion of 150 K (with helium and jacket) is fulfilled for an initial quench length of 1 m, whereas this criterion is exceed (Tmax ≈ 200 K) for an extremely short length of 5 cm. These analyses were carried out using both the Supermagnet(trade mark, serif) and Venecia codes and the comparisons of the results are also discussed

In Situ Warming and Soil Venting to Enhance the Biodegradation of JP-4 in Cold Climates: A Critical Study and Analysis

Science.gov (United States)

1995-12-01

1178-1180 (1991). Atlas , Ronald M. and Richard Bartha . Microbial Ecology : Fundamentals and Applications. 3d ed. Redwood City CA: The Benjamin/Cummings...technique called bioventing. In cold climates, in situ bioremediation is limited to the summer when soil temperatures are sufficient to support microbial ...actively warmed the soil -- warm water circulation and heat tape; the other passively warmed the plot with insulatory covers. Microbial respiration (02

Impact of high resolution land surface initialization in Indian summer ...

Indian Academy of Sciences (India)

The direct impact of high resolution land surface initialization on the forecast bias in a regional climate model in recent years ... surface initialization using a regional climate model. ...... ization of the snow field in a cloud model; J. Clim. Appl.

Initial Analysis of VOCs Speciation in CREATE Emissions Inventory using the MAPS-Seoul Aircraft Field Campaign

Science.gov (United States)

Bu, C.; Woo, J. H.; Lee, Y.; Kim, J.; Choi, K. C.; Kim, Y.; Kim, J.; Jang, Y. K.; Kim, S.

2016-12-01

As the first international cooperative air quality field study, the MAPS-Seoul (Megacity Air Pollution Studies-Seoul) aircraft mission was conducted in May - June 2016 over the South Korea, to understand of climate and atmospheric environment. The aircraft carried observation instruments for measurements of GHGs, ozone and its precursors, aerosols, and chemical tracers. The CREATE (Comprehensive Regional Emissions inventory for Atmospheric Environment) emissions inventory and SMOKE-Asia emission processing system were used to support chemical forecasting and to serve as a priori for evaluation. Initial results of comparison studies show large discrepancies in VOC species over the South Korea - especially over urban regions. Several VOC species observed high near megacities and petro-chemical plants but under-predicted by chemical transport models (CTMs) - possibly due to relatively low emissions. The chemical speciation profiles and emissions inventory for each emission sources, therefore, have to be re-visited to improve emissions information. In this study, we have; 1) re-examined our emissions inventory and emission speciation processes, 2) and tried to find possible missing sources and alternative chemical speciation profiles, to improve our modelling emissions inventory. Initial review of the mapping and classification profiles, the original US chemical speciation profiles were found to be low in partitioning painting and surface coating sources, although they are the very significant contributors. Unlike other major national cities in China, Shanghai's VOC emissions fraction seems very similar to that of Seoul. Continuous analysis of major urban and industrial areas of the country will be presented at site.Acknowledgements : This subject is supported by Korea Ministry of Environment as "Climate Change Correspondence Program". This work was supported by a grant from the National Institute of Environment Research (NIER), funded by the Ministry of Environment

The transverse field Richtmyer-Meshkov instability in magnetohydrodynamics

KAUST Repository

Wheatley, V.; Samtaney, Ravi; Pullin, D. I.; Gehre, R. M.

2014-01-01

The magnetohydrodynamic Richtmyer-Meshkov instability is investigated for the case where the initial magnetic field is unperturbed and aligned with the mean interface location. For this initial condition, the magnetic field lines penetrate the perturbed density interface, forbidding a tangential velocity jump and therefore the presence of a vortex sheet. Through simulation, we find that the vorticity distribution present on the interface immediately after the shock acceleration breaks up into waves traveling parallel and anti-parallel to the magnetic field, which transport the vorticity. The interference of these waves as they propagate causes the perturbation amplitude of the interface to oscillate in time. This interface behavior is accurately predicted over a broad range of parameters by an incompressible linearized model derived presently by solving the corresponding impulse driven, linearized initial value problem. Our use of an equilibrium initial condition results in interface motion produced solely by the impulsive acceleration. Nonlinear compressible simulations are used to investigate the behavior of the transverse field magnetohydrodynamic Richtmyer-Meshkov instability, and the performance of the incompressible model, over a range of shock strengths, magnetic field strengths, perturbation amplitudes and Atwood numbers.

The transverse field Richtmyer-Meshkov instability in magnetohydrodynamics

KAUST Repository

Wheatley, V.

2014-01-10

The magnetohydrodynamic Richtmyer-Meshkov instability is investigated for the case where the initial magnetic field is unperturbed and aligned with the mean interface location. For this initial condition, the magnetic field lines penetrate the perturbed density interface, forbidding a tangential velocity jump and therefore the presence of a vortex sheet. Through simulation, we find that the vorticity distribution present on the interface immediately after the shock acceleration breaks up into waves traveling parallel and anti-parallel to the magnetic field, which transport the vorticity. The interference of these waves as they propagate causes the perturbation amplitude of the interface to oscillate in time. This interface behavior is accurately predicted over a broad range of parameters by an incompressible linearized model derived presently by solving the corresponding impulse driven, linearized initial value problem. Our use of an equilibrium initial condition results in interface motion produced solely by the impulsive acceleration. Nonlinear compressible simulations are used to investigate the behavior of the transverse field magnetohydrodynamic Richtmyer-Meshkov instability, and the performance of the incompressible model, over a range of shock strengths, magnetic field strengths, perturbation amplitudes and Atwood numbers.

Profiles of an initially perturbed electron beam

International Nuclear Information System (INIS)

Abdelsalam, F.W.

1991-01-01

This paper discusses the solutions for the profiles of an electron beam which is launched into a constant magnetic field with an initial boundary slope and injected with a radius which is greater or less than the cathode radius. It has been found that the outermost electron traces sine waves and executes limited excursions when the initial boundary slope corresponds to angles up to 1 degree, no matter whether the initial radius is 0.90 or 1.10 times the radius of the cathode. For initial inclination angles close to 2 degrees, the beam boundary does not preserve a sinusoidal shape, this statement holds true for focusing magnetic flux densities varying from 200x10 -4 to 700x10 -4 weber per square meter

Passive notch circuit for pulsed-off compression fields

International Nuclear Information System (INIS)

Nunnally, W.C.

1976-06-01

The operation and simulated results of a passive notch circuit used to pulse off the field in a multiturn, fusion-power system, compression coil are presented. The notch circuit permits initial plasma preparation at field zero, adiabatic compression as the field returns to its initial value, and long field decay time for plasma confinement. The major advantages and disadvantages of the notch circuit are compared with those of a standard capacitor power supply system. The major advantages are that: (1) slow-rising fields can be used for adiabatic compression, (2) solid-state switches can be used because of the inherent current and voltage waveforms, and (3) long field decay times are easier to attain than with single-turn coils

The Southern African Regional Science Initiative (SAFARI 2000): Overview of the Dry Season Field Campaign

Science.gov (United States)

Swap, R. J.; Annegarn, H. J.; Suttles, J. T.; Haywood, J.; Helmlinger, M. C.; Hely, C.; Hobbs, P. V.; Holben, B. N.; Ji, J.; King, M. D.

2002-01-01

The Southern African Regional Science Initiative (SAFARI 2000) is an international project investigating the earth atmosphere -human system in southern Africa. The programme was conducted over a two year period from March 1999 to March 2001. The dry season field campaign (August-September 2000) was the most intensive activity involved over 200 scientist from eighteen countries. The main objectives were to characterize and quantify biogenic, pyrogenic and anthropogenic aerosol and trace gas emissions and their transport and transformations in the atmosphere and to validate NASA's Earth Observing System's Satellite Terra within a scientific context. Five aircraft-- two South African Weather Service Aeorcommanders, the University of Washington's CV-880, the U.K. Meteorological Office's C-130, and NASA's ER-2 --with different altitude capabilities, participated in the campaign. Additional airborne sampling of southern African air masses, that had moved downwind of the subcontinent, was conducted by the CSIRO over Australia. Multiple Observations were made in various geographical sections under different synoptic conditions. Airborne missions were designed to optimize the value of synchronous over-flights of the Terra Satellite platform, above regional ground validation and science targets. Numerous smaller scale ground validation activities took place throughout the subcontinent during the campaign period.

Field Operations For The "Intelligent River" Observation System: A Basin-wide Water Quality Observation System In The Savannah River Basin And Platform Supporting Related Diverse Initiatives.

Science.gov (United States)

Sutton, A.; Koons, M.; O'Brien-Gayes, P.; Moorer, R.; Hallstrom, J.; Post, C.; Gayes, P. T.

2017-12-01

The Intelligent River (IR) initiative is an NSF sponsored study developing new data management technology for a range of basin-scale applications. The technology developed by Florida Atlantic and Clemson University established a network of real-time reporting water quality sondes; from the mountains to the estuary of the Savannah River basin. Coastal Carolina University led the field operations campaign. Ancillary studies, student projects and initiatives benefitted from the associated instrumentation, infrastructure and operational support of the IR program. This provided a vehicle for students to participate in fieldwork across the watershed and pursue individual interests. Student projects included: 1) a Multibeam sonar survey investigating channel morphology in the area of an IR sensor station and 2) field tests of developing techniques for acquiring and assimilating flood velocity data into model systems associated with a separate NSF Rapid award. The multibeam survey within the lower Savannah basin exhibited a range of complexity in bathymetry, bedforms and bottom habitat in the vicinity of one of the water quality stations. The complex morphology and bottom habitat reflect complex flow patterns, localized areas of depositional and erosive tendencies providing a valuable context for considering point-source water quality time series. Micro- Lagrangian drifters developed by ISENSE at Florida Atlantic University, a sled mounted ADCP, and particle tracking from imagery collected by a photogrammetric drone were tested and used to develop methodology for establishing velocity, direction and discharge levels to validate, initialize and assimilate data into advance models systems during future flood events. The prospect of expanding wide scale observing systems can serve as a platform to integrate small and large-scale cooperative studies across disciplines as well as basic and applied research interests. Such initiatives provide opportunities for embedded education

Back-reaction beyond the mean field approximation

International Nuclear Information System (INIS)

Kluger, Y.

1993-01-01

A method for solving an initial value problem of a closed system consisting of an electromagnetic mean field and its quantum fluctuations coupled to fermions is presented. By tailoring the large N f expansion method to the Schwinger-Keldysh closed time path (CTP) formulation of the quantum effective action, causality of the resulting equations of motion is ensured, and a systematic energy conserving and gauge invariant expansion about the electromagnetic mean field in powers of 1/N f is developed. The resulting equations may be used to study the quantum nonequilibrium effects of pair creation in strong electric fields and the scattering and transport processes of a relativistic e + e - plasma. Using the Bjorken ansatz of boost invariance initial conditions in which the initial electric mean field depends on the proper time only, we show numerical results for the case in which the N f expansion is truncated in the lowest order, and compare them with those of a phenomenological transport equation

Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

International Nuclear Information System (INIS)

Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

1980-01-01

Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

International Nuclear Information System (INIS)

Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

1980-01-01

Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are dramatically improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

Vacuum type D initial data

Science.gov (United States)

García-Parrado Gómez-Lobo, Alfonso

2016-09-01

A vacuum type D initial data set is a vacuum initial data set of the Einstein field equations whose data development contains a region where the space–time is of Petrov type D. In this paper we give a systematic characterisation of a vacuum type D initial data set. By systematic we mean that the only quantities involved are those appearing in the vacuum constraints, namely the first fundamental form (Riemannian metric) and the second fundamental form. Our characterisation is a set of conditions consisting of the vacuum constraints and some additional differential equations for the first and second fundamental forms These conditions can be regarded as a system of partial differential equations on a Riemannian manifold and the solutions of the system contain all possible regular vacuum type D initial data sets. As an application we particularise our conditions for the case of vacuum data whose data development is a subset of the Kerr solution. This has applications in the formulation of the nonlinear stability problem of the Kerr black hole.

Initial magnetic susceptibility of the diluted magnetopolymer elastic composites

International Nuclear Information System (INIS)

Borin, D.Yu.; Odenbach, S.

2017-01-01

In this work diluted magnetopolymer elastic composites based on magnetic microparticles are experimentally studied. Considered samples have varied concentration of the magnetic powder and different structural anisotropy. Experimental data on magnetic properties are accomplished by microstructural observations performed using X-Ray tomography. Influence of the particles amount and structuring effects on the initial magnetic susceptibility of the composites as well as the applicability of the Maxwell-Garnett approximation, which is widely used in considerations of magnetopolymer elastic composites, are evaluated. It is demonstrated that the approximation works well for diluted samples containing randomly distributed magnetic particles and for the diluted samples with chain-like structures oriented perpendicular to an externally applied field, while it fails to predict the susceptibility of the samples with structures oriented parallel to the field. Moreover, it is shown, that variation of the chains morphology does not significantly change the composite initial magnetic susceptibility. - Highlights: • The Maxwell-Garnet prediction works well for the diluted isotropic composites. • The Maxwell-Garnet prediction can be used for composites with structures oriented perpendicular to an applied field. • Chains oriented parallel to an applied field significantly increase the composite initial magnetic susceptibility. • The number and thickness of chains is not of the highest importance for the diluted composites. • The crucial reason of the observed effect is expected to be the demagnetisation factor of the chains.

ENERGETIC PARTICLE TRANSPORT ACROSS THE MEAN MAGNETIC FIELD: BEFORE DIFFUSION

International Nuclear Information System (INIS)

Laitinen, T.; Dalla, S.

2017-01-01

Current particle transport models describe the propagation of charged particles across the mean field direction in turbulent plasmas as diffusion. However, recent studies suggest that at short timescales, such as soon after solar energetic particle (SEP) injection, particles remain on turbulently meandering field lines, which results in nondiffusive initial propagation across the mean magnetic field. In this work, we use a new technique to investigate how the particles are displaced from their original field lines, and we quantify the parameters of the transition from field-aligned particle propagation along meandering field lines to particle diffusion across the mean magnetic field. We show that the initial decoupling of the particles from the field lines is slow, and particles remain within a Larmor radius from their initial meandering field lines for tens to hundreds of Larmor periods, for 0.1–10 MeV protons in turbulence conditions typical of the solar wind at 1 au. Subsequently, particles decouple from their initial field lines and after hundreds to thousands of Larmor periods reach time-asymptotic diffusive behavior consistent with particle diffusion across the mean field caused by the meandering of the field lines. We show that the typical duration of the prediffusive phase, hours to tens of hours for 10 MeV protons in 1 au solar wind turbulence conditions, is significant for SEP propagation to 1 au and must be taken into account when modeling SEP propagation in the interplanetary space.

ENERGETIC PARTICLE TRANSPORT ACROSS THE MEAN MAGNETIC FIELD: BEFORE DIFFUSION

Energy Technology Data Exchange (ETDEWEB)

Laitinen, T.; Dalla, S., E-mail: tlmlaitinen@uclan.ac.uk [Jeremiah Horrocks Institute, University of Central Lancashire, Preston (United Kingdom)

2017-01-10

Current particle transport models describe the propagation of charged particles across the mean field direction in turbulent plasmas as diffusion. However, recent studies suggest that at short timescales, such as soon after solar energetic particle (SEP) injection, particles remain on turbulently meandering field lines, which results in nondiffusive initial propagation across the mean magnetic field. In this work, we use a new technique to investigate how the particles are displaced from their original field lines, and we quantify the parameters of the transition from field-aligned particle propagation along meandering field lines to particle diffusion across the mean magnetic field. We show that the initial decoupling of the particles from the field lines is slow, and particles remain within a Larmor radius from their initial meandering field lines for tens to hundreds of Larmor periods, for 0.1–10 MeV protons in turbulence conditions typical of the solar wind at 1 au. Subsequently, particles decouple from their initial field lines and after hundreds to thousands of Larmor periods reach time-asymptotic diffusive behavior consistent with particle diffusion across the mean field caused by the meandering of the field lines. We show that the typical duration of the prediffusive phase, hours to tens of hours for 10 MeV protons in 1 au solar wind turbulence conditions, is significant for SEP propagation to 1 au and must be taken into account when modeling SEP propagation in the interplanetary space.

THE TOPOLOGICAL CHANGES OF SOLAR CORONAL MAGNETIC FIELDS. II. THE RECLOSING OF AN OPENED FIELD

International Nuclear Information System (INIS)

Low, B. C.; Janse, A. M.

2009-01-01

This is a study of the spontaneous formation of current sheets responding to the closing of an opened magnetic field by resistive reconnection in an electrically, highly conducting atmosphere outside a unit sphere. Pairs of initial-final equilibrium states are calculated explicitly, taking the field to be composed of three systems of untwisted flux in both states. In the initial state, two of the three flux systems are closed potential fields whereas the third system contains an equilibrium current sheet that keeps the potential fields on its two sides globally open. The final state is an everywhere potential field, with all three flux systems closed, produced by the resistive dissipation of the current sheet in the initial state. The unit sphere is taken to be a rigid, perfectly conducting wall during reconnection, so that the normal flux distribution is unchanged on the unit sphere. Field solutions subject to this unchanging boundary condition are obtained with and without the assumption of axisymmetry. The mathematical model has been designed to show that the topological changes produced by the current-sheet dissipation are simple under axisymmetry but radically different in the absence of axisymmetry, a fundamental point established in the first paper of this series. In the general case, the topological changes imply that other current sheets must have formed. Some of these current sheets form on the separatrix flux surfaces of the multipolar field. Others form throughout the closed-flux systems induced by volumetric changes. The opening and reclosing of magnetic fields during a solar coronal mass ejection may produce a multitude of current sheets not previously anticipated in the current understanding of this phenomenon. Basic to this study is a general topological property of magnetic flux tubes treated separately in the Appendix.

Impact of local electrostatic field rearrangement on field ionization

Science.gov (United States)

Katnagallu, Shyam; Dagan, Michal; Parviainen, Stefan; Nematollahi, Ali; Grabowski, Blazej; Bagot, Paul A. J.; Rolland, Nicolas; Neugebauer, Jörg; Raabe, Dierk; Vurpillot, François; Moody, Michael P.; Gault, Baptiste

2018-03-01

Field ion microscopy allows for direct imaging of surfaces with true atomic resolution. The high charge density distribution on the surface generates an intense electric field that can induce ionization of gas atoms. We investigate the dynamic nature of the charge and the consequent electrostatic field redistribution following the departure of atoms initially constituting the surface in the form of an ion, a process known as field evaporation. We report on a new algorithm for image processing and tracking of individual atoms on the specimen surface enabling quantitative assessment of shifts in the imaged atomic positions. By combining experimental investigations with molecular dynamics simulations, which include the full electric charge, we confirm that change is directly associated with the rearrangement of the electrostatic field that modifies the imaging gas ionization zone. We derive important considerations for future developments of data reconstruction in 3D field ion microscopy, in particular for precise quantification of lattice strains and characterization of crystalline defects at the atomic scale.

The initial value problem as it relates to numerical relativity.

Science.gov (United States)

Tichy, Wolfgang

2017-02-01

Spacetime is foliated by spatial hypersurfaces in the 3+1 split of general relativity. The initial value problem then consists of specifying initial data for all fields on one such a spatial hypersurface, such that the subsequent evolution forward in time is fully determined. On each hypersurface the 3-metric and extrinsic curvature describe the geometry. Together with matter fields such as fluid velocity, energy density and rest mass density, the 3-metric and extrinsic curvature then constitute the initial data. There is a lot of freedom in choosing such initial data. This freedom corresponds to the physical state of the system at the initial time. At the same time the initial data have to satisfy the Hamiltonian and momentum constraint equations of general relativity and can thus not be chosen completely freely. We discuss the conformal transverse traceless and conformal thin sandwich decompositions that are commonly used in the construction of constraint satisfying initial data. These decompositions allow us to specify certain free data that describe the physical nature of the system. The remaining metric fields are then determined by solving elliptic equations derived from the constraint equations. We describe initial data for single black holes and single neutron stars, and how we can use conformal decompositions to construct initial data for binaries made up of black holes or neutron stars. Orbiting binaries will emit gravitational radiation and thus lose energy. Since the emitted radiation tends to circularize the orbits over time, one can thus expect that the objects in a typical binary move on almost circular orbits with slowly shrinking radii. This leads us to the concept of quasi-equilibrium, which essentially assumes that time derivatives are negligible in corotating coordinates for binaries on almost circular orbits. We review how quasi-equilibrium assumptions can be used to make physically well motivated approximations that simplify the elliptic

Light-initiated detonation systems

Science.gov (United States)

Cooper, Stafford S.; Malone, Philip G.; Bartholomew, Stephen W.; Necker, William J.

1986-09-01

Numerous light sources could be employed in detonation systems, but lasers have the most efficient coupling to optical fibers and can generate energetic light pulses required for detonation. Flash lamp-pumped, solid state lasers are presently the most useful light source for explosive initiation. Laser diodes in current production cannot generate enough energy for practical applications. The most useful optical fiber for blast line application is a step index fiber with a large core-to-cladding ratio. The large core minimizes energy losses due to misalignment core of fibers in connectors. Couplers that involve mechanically crimped connectors and cleaved fibers, rather than the epoxy-cemented connectors with polished fibers, provide superior energy transmission due to the reduced carbonization at the fiber end. Detonators for optical initiation systems are similar in basic construction to those employed in electrical initiation systems. Explosive and pyrotechnic charges can also be similar. Either primary or secondary explosives can be initiated in present laser-based systems. Two laser detonation systems are presently accessible; a multiple-shot laser with a single-shot, single fiber system designed for use with detonators containing primary explosives. Additional research related to development of low-energy, photoreactive detonators, continuity checking techniques and improved connectors and fibers can produce significant improvements in presently fielded systems.

Appendix I1-2 to Wind HUI Initiative 1: Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

John Zack; Deborah Hanley; Dora Nakafuji

2012-07-15

This report is an appendix to the Hawaii WindHUI efforts to dev elop and operationalize short-term wind forecasting and wind ramp event forecasting capabilities. The report summarizes the WindNET field campaign deployment experiences and challenges. As part of the WindNET project on the Big Island of Hawaii, AWS Truepower (AWST) conducted a field campaign to assess the viability of deploying a network of monitoring systems to aid in local wind energy forecasting. The data provided at these monitoring locations, which were strategically placed around the Big Island of Hawaii based upon results from the Oahu Wind Integration and Transmission Study (OWITS) observational targeting study (Figure 1), provided predictive indicators for improving wind forecasts and developing responsive strategies for managing real-time, wind-related system events. The goal of the field campaign was to make measurements from a network of remote monitoring devices to improve 1- to 3-hour look ahead forecasts for wind facilities.

Diffusive processes in a stochastic magnetic field

International Nuclear Information System (INIS)

Wang, H.; Vlad, M.; Vanden Eijnden, E.; Spineanu, F.; Misguich, J.H.; Balescu, R.

1995-01-01

The statistical representation of a fluctuating (stochastic) magnetic field configuration is studied in detail. The Eulerian correlation functions of the magnetic field are determined, taking into account all geometrical constraints: these objects form a nondiagonal matrix. The Lagrangian correlations, within the reasonable Corrsin approximation, are reduced to a single scalar function, determined by an integral equation. The mean square perpendicular deviation of a geometrical point moving along a perturbed field line is determined by a nonlinear second-order differential equation. The separation of neighboring field lines in a stochastic magnetic field is studied. We find exponentiation lengths of both signs describing, in particular, a decay (on the average) of any initial anisotropy. The vanishing sum of these exponentiation lengths ensures the existence of an invariant which was overlooked in previous works. Next, the separation of a particle's trajectory from the magnetic field line to which it was initially attached is studied by a similar method. Here too an initial phase of exponential separation appears. Assuming the existence of a final diffusive phase, anomalous diffusion coefficients are found for both weakly and strongly collisional limits. The latter is identical to the well known Rechester-Rosenbluth coefficient, which is obtained here by a more quantitative (though not entirely deductive) treatment than in earlier works

Tree-level correlations in the strong field regime

Science.gov (United States)

Gelis, François

2017-09-01

We consider the correlation function of an arbitrary number of local observables in quantum field theory, in situations where the field amplitude is large. Using a quasi-classical approximation (valid for a highly occupied initial mixed state, or for a coherent initial state if the classical dynamics has instabilities), we show that at tree level these correlations are dominated by fluctuations at the initial time. We obtain a general expression of the correlation functions in terms of the classical solution of the field equation of motion and its derivatives with respect to its initial conditions, that can be arranged graphically as the sum of labeled trees where the nodes are the individual observables, and the links are pairs of derivatives acting on them. For 3-point (and higher) correlation functions, there are additional tree-level terms beyond the quasi-classical approximation, generated by fluctuations in the bulk.

Pyrolysis of attapulgite clay blended with yak dung enhances pasture growth and soil health: Characterization and initial field trials.

Science.gov (United States)

Rafiq, Muhammad Khalid; Joseph, Stephen D; Li, Fei; Bai, Yanfu; Shang, Zhanhuan; Rawal, Aditya; Hook, James M; Munroe, Paul R; Donne, Scott; Taherymoosavi, Sara; Mitchell, David R G; Pace, Ben; Mohammed, Mohanad; Horvat, Joseph; Marjo, Christopher E; Wagner, Avital; Wang, Yanlong; Ye, Jun; Long, Rui-Jun

2017-12-31

Recent studies have shown that the pyrolysis of biomass combined with clay can result in both lower cost and increase in plant yields. One of the major sources of nutrients for pasture growth, as well as fuel and building materials in Tibet is yak dung. This paper reports on the initial field testing in a pasture setting in Tibet using yak dung, biochar, and attapulgite clay/yak dung biochars produced at ratios of 10/90 and 50/50 clay to dung. We found that the treatment with attapulgite clay/yak dung (50/50) biochar resulted in the highest pasture yields and grass nutrition quality. We also measured the properties and yields of mixtures of clay/yak dung biochar used in the field trials produced at 400°C and 500°C to help determine a possible optimum final pyrolysis temperature and dung/clay ratio. It was observed that increasing clay content increased carbon stability, overall biochar yield, pore size, carboxyl and ketone/aldehyde functional groups, hematite and ferrous/ferric sulphate/thiosulphate concentration, surface area and magnetic moment. Decreasing clay content resulted in higher pH, CEC, N content and an enhanced ability to accept and donate electrons. The resulting properties were a complex function of both processing temperature and the percentage of clay for the biochars processed at both 400°C and 500°C. It is possible that the increase in yield and nutrient uptake in the field trial is related to the higher concentration of C/O functional groups, higher surface area and pore volume and higher content of Fe/O/S nanoparticles of multiple oxidation state in the 50/50 clay/dung. These properties have been found to significantly increase the abundance of beneficial microorganisms and hence improve the nutrient cycling and availability in soil. Further field trials are required to determine the optimum pyrolysis production conditions and application rate on the abundance of beneficial microorganisms, yields and nutrient quality. Copyright © 2017

Applying PPM to ERP Maintenance and Continuous Improvement Initiatives

DEFF Research Database (Denmark)

El-Tal, Nada Maria; Fonnesbæk, Majbrit; Kræmmergaard, Pernille

2006-01-01

to gain business benefits from the systems. However the ERP literature on how to do this is limited. The purpose of this article is to explore how Project Portfolio Management (PPM) from the Research and Development (R&D) literature can be applied to an ERP second wave context, when companies...... are to prioritize and select maintenance and continuous improvement initiatives. This is done by reviewing the existing literature in the fields of PPM from R&D literature and then by reviewing the existing literature about maintenance and improvement initiatives in the ERP literature, after which the two...... are compared and discussed using three case-studies. The paper contributes with a discussion on how PPM from R&D can be applied to maintenance and continuous improvement initiatives in the second wave of ERP. The paper ends with arguing that emphasis needs to be given to this field, since a conscious...

TESTING MAGNETIC FIELD MODELS FOR THE CLASS 0 PROTOSTAR L1527

International Nuclear Information System (INIS)

Davidson, J. A.; Li, Z.-Y.; Hull, C. L. H.; Plambeck, R. L.; Kwon, W.; Crutcher, R. M.; Looney, L. W.; Novak, G.; Chapman, N. L.; Matthews, B. C.; Stephens, I. W.; Tobin, J. J.; Jones, T. J.

2014-01-01

For the Class 0 protostar L1527 we compare 131 polarization vectors from SCUPOL/JCMT, SHARP/CSO, and TADPOL/CARMA observations with the corresponding model polarization vectors of four ideal-MHD, nonturbulent, cloud core collapse models. These four models differ by their initial magnetic fields before collapse; two initially have aligned fields (strong and weak) and two initially have orthogonal fields (strong and weak) with respect to the rotation axis of the L1527 core. Only the initial weak orthogonal field model produces the observed circumstellar disk within L1527. This is a characteristic of nearly all ideal-MHD, nonturbulent, core collapse models. In this paper we test whether this weak orthogonal model also has the best agreement between its magnetic field structure and that inferred from the polarimetry observations of L1527. We found that this is not the case; based on the polarimetry observations, the most favored model of the four is the weak aligned model. However, this model does not produce a circumstellar disk, so our result implies that a nonturbulent, ideal-MHD global collapse model probably does not represent the core collapse that has occurred in L1527. Our study also illustrates the importance of using polarization vectors covering a large area of a cloud core to determine the initial magnetic field orientation before collapse; the inner core magnetic field structure can be highly altered by a collapse, and so measurements from this region alone can give unreliable estimates of the initial field configuration before collapse

TESTING MAGNETIC FIELD MODELS FOR THE CLASS 0 PROTOSTAR L1527

Energy Technology Data Exchange (ETDEWEB)

Davidson, J. A. [University of Western Australia, School of Physics, 35 Stirling Highway, Crawley, WA 6009 (Australia); Li, Z.-Y. [Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States); Hull, C. L. H.; Plambeck, R. L. [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 (United States); Kwon, W. [SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD, Groningen (Netherlands); Crutcher, R. M.; Looney, L. W. [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Novak, G.; Chapman, N. L. [Northwestern University, Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Matthews, B. C. [Herzberg Astronomy and Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Stephens, I. W. [Boston University, Institute for Astrophysical Research, Boston, MA 02215 (United States); Tobin, J. J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Jones, T. J., E-mail: jackie.davidson@uwa.edu.au [University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

2014-12-20

For the Class 0 protostar L1527 we compare 131 polarization vectors from SCUPOL/JCMT, SHARP/CSO, and TADPOL/CARMA observations with the corresponding model polarization vectors of four ideal-MHD, nonturbulent, cloud core collapse models. These four models differ by their initial magnetic fields before collapse; two initially have aligned fields (strong and weak) and two initially have orthogonal fields (strong and weak) with respect to the rotation axis of the L1527 core. Only the initial weak orthogonal field model produces the observed circumstellar disk within L1527. This is a characteristic of nearly all ideal-MHD, nonturbulent, core collapse models. In this paper we test whether this weak orthogonal model also has the best agreement between its magnetic field structure and that inferred from the polarimetry observations of L1527. We found that this is not the case; based on the polarimetry observations, the most favored model of the four is the weak aligned model. However, this model does not produce a circumstellar disk, so our result implies that a nonturbulent, ideal-MHD global collapse model probably does not represent the core collapse that has occurred in L1527. Our study also illustrates the importance of using polarization vectors covering a large area of a cloud core to determine the initial magnetic field orientation before collapse; the inner core magnetic field structure can be highly altered by a collapse, and so measurements from this region alone can give unreliable estimates of the initial field configuration before collapse.

Gauge fields and inflation

Science.gov (United States)

Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.

2013-07-01

The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic

Gravitational Collapse of Massless Fields in an Expanding Universe

Directory of Open Access Journals (Sweden)

Yoo Chul-Moon

2018-01-01

Full Text Available Gravitational collapse of a massless scalar field with the periodic boundary condition in a cubic box is reported. This system can be regarded as a lattice universe model. The initial data is constructed for a Gaussian like profile of the scalar field taking the integrability condition associated with the periodic boundary condition into account. For a large initial amplitude, a black hole is formed after a certain period of time. While the scalar field spreads out in the whole region for a small initial amplitude. The difference of the late time expansion law of the lattice universe depending on the final fate of the gravitational collapse is discussed.

Analytical expression for initial magnetization curve of Fe-based soft magnetic composite material

Energy Technology Data Exchange (ETDEWEB)

Birčáková, Zuzana, E-mail: zuzana.bircakova@upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 04154 Košice (Slovakia); Kollár, Peter; Füzer, Ján [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 04154 Košice (Slovakia); Bureš, Radovan; Fáberová, Mária [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia)

2017-02-01

The analytical expression for the initial magnetization curve for Fe-phenolphormaldehyde resin composite material was derived based on the already proposed ideas of the magnetization vector deviation function and the domain wall annihilation function, characterizing the reversible magnetization processes through the extent of deviation of magnetization vectors from magnetic field direction and the irreversible processes through the effective numbers of movable domain walls, respectively. As for composite materials the specific dependences of these functions were observed, the ideas were extended meeting the composites special features, which are principally the much higher inner demagnetizing fields produced by magnetic poles on ferromagnetic particle surfaces. The proposed analytical expression enables us to find the relative extent of each type of magnetization processes when magnetizing a specimen along the initial curve. - Highlights: • Analytical expression of the initial curve derived for SMC. • Initial curve described by elementary magnetization processes. • Influence of inner demagnetizing fields on magnetization process in SMC.

Initial-boundary-value problem of the self-gravitating scalar field in the Bondi-Sachs gauge

International Nuclear Information System (INIS)

Frittelli, Simonetta; Gomez, Roberto

2007-01-01

It is shown that, in the Bondi-Sachs gauge that fixes the speed of incoming light rays to the value 1, the Einstein equations coupled to a scalar field in spherical symmetry are cast into a symmetric-hyperbolic system of equations for the scalar field, lapse and shift as fundamental variables. In this system of equations, the lapse and shift are incoming characteristic fields, and the scalar field has three components: incoming, outgoing and static. A constraint-preserving boundary condition is prescribed by imposing the projection of the Einstein equation normal to the boundary at the outer value of the radial coordinate. The boundary condition specifies one of the two incoming metric fields. The remaining incoming metric field and the incoming scalar field component need to be specified arbitrarily. Numerical simulations of the scattering of the scalar field by a black hole in the nonlinear regime are presented that illustrate interesting facts about black-hole physics and the behavior of the characteristic variables of the problem

Field Model: An Object-Oriented Data Model for Fields

Science.gov (United States)

Moran, Patrick J.

2001-01-01

We present an extensible, object-oriented data model designed for field data entitled Field Model (FM). FM objects can represent a wide variety of fields, including fields of arbitrary dimension and node type. FM can also handle time-series data. FM achieves generality through carefully selected topological primitives and through an implementation that leverages the potential of templated C++. FM supports fields where the nodes values are paired with any cell type. Thus FM can represent data where the field nodes are paired with the vertices ("vertex-centered" data), fields where the nodes are paired with the D-dimensional cells in R(sup D) (often called "cell-centered" data), as well as fields where nodes are paired with edges or other cell types. FM is designed to effectively handle very large data sets; in particular FM employs a demand-driven evaluation strategy that works especially well with large field data. Finally, the interfaces developed for FM have the potential to effectively abstract field data based on adaptive meshes. We present initial results with a triangular adaptive grid in R(sup 2) and discuss how the same design abstractions would work equally well with other adaptive-grid variations, including meshes in R(sup 3).

Improvement in equipment for initiating combustion of bituminous beds

Energy Technology Data Exchange (ETDEWEB)

Kleyev, A M; Galimov, R R; Smerkovich, Y S

1981-01-01

An experimental sample of a unit is developed based on the logging lifter PK-2 which was tested with initiation of intrabed combustion at the Sugushlinskiy field (viscosity of bitumen over 10/sup 3/ Pa.s) and Mordovo-Karmal'skiy field (viscosity of bitumen up to 3 Pa.s). Technical characteristics and operating principles of the unit are presented.

Strengthening field epidemiology in Africa: The Zimbabwe Field ...

African Journals Online (AJOL)

In addition the health directorates of the major cities in the country are designated field training sites. Since 1993, the program has had 18 Cohorts trained of which three are part-time. The part-time program was initiated in 2008 with an intake of 10 trainees. Since 2003, the full time program has experienced an increase in ...

Biological Treatment of Petroleum in Radiologically Contaminated Soil

Energy Technology Data Exchange (ETDEWEB)

BERRY, CHRISTOPHER

2005-11-14

This chapter describes ex situ bioremediation of the petroleum portion of radiologically co-contaminated soils using microorganisms isolated from a waste site and innovative bioreactor technology. Microorganisms first isolated and screened in the laboratory for bioremediation of petroleum were eventually used to treat soils in a bioreactor. The bioreactor treated soils contaminated with over 20,000 mg/kg total petroleum hydrocarbon and reduced the levels to less than 100 mg/kg in 22 months. After treatment, the soils were permanently disposed as low-level radiological waste. The petroleum and radiologically contaminated soil (PRCS) bioreactor operated using bioventing to control the supply of oxygen (air) to the soil being treated. The system treated 3.67 tons of PCRS amended with weathered compost, ammonium nitrate, fertilizer, and water. In addition, a consortium of microbes (patent pending) isolated at the Savannah River National Laboratory from a petroleum-contaminated site was added to the PRCS system. During operation, degradation of petroleum waste was accounted for through monitoring of carbon dioxide levels in the system effluent. The project demonstrated that co-contaminated soils could be successfully treated through bioventing and bioaugmentation to remove petroleum contamination to levels below 100 mg/kg while protecting workers and the environment from radiological contamination.

Paramedic Initiation of Neuroprotective Agent Infusions: Successful Achievement of Target Blood Levels and Attained Level Effect on Clinical Outcomes in the FAST-MAG Pivotal Trial (Field Administration of Stroke Therapy - Magnesium).

Science.gov (United States)

Shkirkova, Kristina; Starkman, Sidney; Sanossian, Nerses; Eckstein, Marc; Stratton, Samuel; Pratt, Frank; Conwit, Robin; Hamilton, Scott; Sharma, Latisha; Liebeskind, David; Restrepo, Lucas; Valdes-Sueiras, Miguel; Saver, Jeffrey L

2017-07-01

Paramedic use of fixed-size lumen, gravity-controlled tubing to initiate intravenous infusions in the field may allow rapid start of neuroprotective therapy for acute stroke. In a large, multicenter trial, we evaluated its efficacy in attaining target serum levels of candidate neuroprotective agent magnesium sulfate and the relation of achieved magnesium levels to outcome. The FAST-MAG phase 3 trial (Field Administration of Stroke Therapy - Magnesium) randomized 1700 patients within 2 hours of onset to paramedic-initiated, a 15-minute loading intravenous infusion of magnesium or placebo followed by a 24-hour maintenance dose. The drug delivery strategy included fixed-size lumen, gravity-controlled tubing for field drug administration, and a shrink-wrapped ambulance kit containing both the randomized field loading and hospital maintenance doses for seamless continuation. Among patient randomized to active treatment, magnesium levels in the first 72 hours were assessed 987 times in 572 patients. Mean patient age was 70 years (SD±14 years), and 45% were women. During the 24-hour period of active infusion, mean achieved serum level was 3.91 (±0.8), consistent with trial target. Mg levels were increased by older age, female sex, lower weight, height, body mass index, and estimated glomerular filtration rate, and higher blood urea nitrogen, hemoglobin, and higher hematocrit. Adjusted odds for clinical outcomes did not differ by achieved Mg level, including disability at 90 days, symptomatic hemorrhage, or death. Paramedic infusion initiation using gravity-controlled tubing permits rapid achievement of target serum levels of potential neuroprotective agents. The absence of association of clinical outcomes with achieved magnesium levels provides further evidence that magnesium is not biologically neuroprotective in acute stroke. © 2017 American Heart Association, Inc.

Modeling of Coastal Effluent Transport: an Approach to Linking of Far-field and Near-field Models

International Nuclear Information System (INIS)

Yang, Zhaoqing; Khangaonkar, Tarang P.

2008-01-01

One of the challenges in effluent transport modeling in coastal tidal environments is the proper calculation of initial dilution in connection with the far-field transport model. In this study, an approach of external linkage of far-field and near-field effluent transport models is presented, and applied to simulate the effluent transport in the Port Angeles Harbor, Washington in the Strait of Juan de Fuca. A near-field plume model was used to calculate the effluent initial dilution and a three-dimensional (3-D) hydrodynamic model was developed to simulate the tidal circulation and far-field effluent transport in the Port Angeles Harbor. In the present study, the hydrodynamic model was driven by tides and surface winds. Observed water surface elevation and velocity data were used to calibrate the model over a period covering the neap-spring tidal cycle. The model was also validated with observed surface drogue trajectory data. The model successfully reproduced the tidal dynamics in the study area and good agreements between model results and observed data were obtained. This study demonstrated that the linkage between the near-field and far-field models in effluent transport modeling can be achieved through iteratively adjusting the model grid sizes such that the far-field modeled dilution ratio and effluent concentration in the effluent discharge model grid cell match the concentration calculated by the near-field plume model

The operations of quantum logic gates with pure and mixed initial states.

Science.gov (United States)

Chen, Jun-Liang; Li, Che-Ming; Hwang, Chi-Chuan; Ho, Yi-Hui

2011-04-07

The implementations of quantum logic gates realized by the rovibrational states of a C(12)O(16) molecule in the X((1)Σ(+)) electronic ground state are investigated. Optimal laser fields are obtained by using the modified multitarget optimal theory (MTOCT) which combines the maxima of the cost functional and the fidelity for state and quantum process. The projection operator technique together with modified MTOCT is used to get optimal laser fields. If initial states of the quantum gate are pure states, states at target time approach well to ideal target states. However, if the initial states are mixed states, the target states do not approach well to ideal ones. The process fidelity is introduced to investigate the reliability of the quantum gate operation driven by the optimal laser field. We found that the quantum gates operate reliably whether the initial states are pure or mixed.

Initial conditions for critical Higgs inflation

Science.gov (United States)

Salvio, Alberto

2018-05-01

It has been pointed out that a large non-minimal coupling ξ between the Higgs and the Ricci scalar can source higher derivative operators, which may change the predictions of Higgs inflation. A variant, called critical Higgs inflation, employs the near-criticality of the top mass to introduce an inflection point in the potential and lower drastically the value of ξ. We here study whether critical Higgs inflation can occur even if the pre-inflationary initial conditions do not satisfy the slow-roll behavior (retaining translation and rotation symmetries). A positive answer is found: inflation turns out to be an attractor and therefore no fine-tuning of the initial conditions is necessary. A very large initial Higgs time-derivative (as compared to the potential energy density) is compensated by a moderate increase in the initial field value. These conclusions are reached by solving the exact Higgs equation without using the slow-roll approximation. This also allows us to consistently treat the inflection point, where the standard slow-roll approximation breaks down. Here we make use of an approach that is independent of the UV completion of gravity, by taking initial conditions that always involve sub-planckian energies.

Piezoelectrically Initiated Pyrotechnic Igniter

Science.gov (United States)

Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

2013-01-01

This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first

Random fields of initial out of straightness leading to column buckling

DEFF Research Database (Denmark)

Kala, Zdeněk; Valeš, Jan; Jönsson, Jeppe

2017-01-01

The elastic load-carrying capacity and buckling trajectory of steel columns under compression with open and hollow cross-sections, whose axis is curved by spatial random fields, are studied in the article. As a result of the spatial curvature of the axis the cross-sections are subjected to compre...

Microrelief-Controlled Overland Flow Generation: Laboratory and Field Experiments

Directory of Open Access Journals (Sweden)

Xuefeng Chu

2015-01-01

Full Text Available Surface microrelief affects overland flow generation and the related hydrologic processes. However, such influences vary depending on other factors such as rainfall characteristics, soil properties, and initial soil moisture conditions. Thus, in-depth research is needed to better understand and evaluate the combined effects of these factors on overland flow dynamics. The objective of this experimental study was to examine how surface microrelief, in conjunction with the factors of rainfall, soil, and initial moisture conditions, impacts overland flow generation and runoff processes in both laboratory and field settings. A series of overland flow experiments were conducted for rough and smooth surfaces that represented distinct microtopographic characteristics and the experimental data were analyzed and compared. Across different soil types and initial moisture conditions, both laboratory and field experiments demonstrated that a rough soil surface experienced a delayed initiation of runoff and featured a stepwise threshold flow pattern due to the microrelief-controlled puddle filling-spilling-merging dynamics. It was found from the field experiments that a smooth plot surface was more responsive to rainfall variations especially during an initial rainfall event. However, enhanced capability of overland flow generation and faster puddle connectivity of a rough field plot occurred during the subsequent rain events.

Review of WAG Field Experience

DEFF Research Database (Denmark)

Christensen, Jes Reimer; Stenby, Erling Halfdan; Skauge, A.

2001-01-01

well spacing is in the order of 1000 m. For the fields reviewed, a common trend for the successful injections is an increased oil recovery in the range of 5 to 10% of the oil initially in place (OIIP). Very few field trials have been reported as unsuccessful, but operational problems are often noted...

Deriving force field parameters for coordination complexes

DEFF Research Database (Denmark)

Norrby, Per-Ola; Brandt, Peter

2001-01-01

The process of deriving molecular mechanics force fields for coordination complexes is outlined. Force field basics are introduced with an emphasis on special requirements for metal complexes. The review is then focused on how to set up the initial model, define the target, refine the parameters......, and validate the final force field, Alternatives to force field derivation are discussed briefly....

Initiation devices, initiation systems including initiation devices and related methods

Energy Technology Data Exchange (ETDEWEB)

Daniels, Michael A.; Condit, Reston A.; Rasmussen, Nikki; Wallace, Ronald S.

2018-04-10

Initiation devices may include at least one substrate, an initiation element positioned on a first side of the at least one substrate, and a spark gap electrically coupled to the initiation element and positioned on a second side of the at least one substrate. Initiation devices may include a plurality of substrates where at least one substrate of the plurality of substrates is electrically connected to at least one adjacent substrate of the plurality of substrates with at least one via extending through the at least one substrate. Initiation systems may include such initiation devices. Methods of igniting energetic materials include passing a current through a spark gap formed on at least one substrate of the initiation device, passing the current through at least one via formed through the at least one substrate, and passing the current through an explosive bridge wire of the initiation device.

Assessment of field training for nuclear operations personnel

International Nuclear Information System (INIS)

White, M.

1995-08-01

Training of station personnel is an important component of the safe operation of the nuclear generating station. On-the-job training (OJT) is an important component of training. The AECB initiated this project to develop a process to assess the effectiveness of OJT for field operators, and perform an initial trial of the developed process. This report describes the recommended process to assess the effectiveness of OJT for field operators, as well as the results of the initial assessment at Pickering Nuclear Generating Station. The assessment's conclusions included: (1) Ontario Hydro policies and procedures are generally consistent with industry guidelines requiring a systematic approach to training; (2) Pickering NGS field operator performance is not always consistent with documented station requirements and standards, nor industry guidelines and practices; and (3) The Pickering NGS field operator on-the-job training is not consistent with a systematic approach to training, a requirement recognized in Ontario Hydro's Policy NGD 113, and does not contribute to a high level of performance in field operator tasks. Recommendations are made regarding the use of the developed process for future assessments of on-the-job training at nuclear power plants. (author). 36 refs., 4 tabs., 3 figs

A corporate social responsibility initiative in the field of nuclear power

International Nuclear Information System (INIS)

Stiopol, M.; Rizea, L.

2009-01-01

Societatea Nationala Nuclearelectrica SA is the operator of the Cernavoda nuclear power plant and the second largest energy producer in Romania, after Hidroelectrica, ensuring 18% of the internal energy demand. The production of nuclear power differs from other industrial activities through the risks it involves and through the legacy it leaves to the future generations, i.e. the nuclear waste. Taking into account these considerations, public acceptance represents a constant preoccupation for nuclear companies around the world. Corporate Social Responsibility (CSR) is a new practice in the nuclear industry. After a long tradition of involvement in the life of the local community through the Social Program for Cernavoda, Nuclearelectrica has initiated a CSR campaign with the theme 'Welcome a tree in your family', addressed to pupils and high school students from Cernavoda. By this campaign, we aimed at creating relevance, not just green lots and to launch a chain of reactions among the citizens of Cernavoda through 'word of mouth communication' so that our initiative may become a sustainable activity. In order to establish the basis of a long term program, the essential element was to change the attitude and behavior of the target population from lack of involvement to responsibility towards the environment. The ecological campaign developed in two phases of planting trees, has recorded significant results among the target population increasing the level of information and acceptance towards nuclear power. (authors)

The start of lightning: Evidence of bidirectional lightning initiation

OpenAIRE

van der Velde, Oscar; Williams, Earle R.; Montanya, Joan

2015-01-01

Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leader...

Kinetic approach to the initial value problem in quantum field theory

International Nuclear Information System (INIS)

Lin Chi Yong; Toledo Piza, A.F.R. de.

1989-06-01

Time-dependente projection techniques developed to derive kinetic equations in the context of the quantum many-body problem are applied to φ 4 field theory. The approach is illustrated by working out the 0+1 dimensional case explicitly, including numerical solutions of the kinetic equations. Extension to higher dimensions is briefly discussed. (author) [pt

Initial field test of High-Energy Corona process for treating a contaminated soil-offgas stream

International Nuclear Information System (INIS)

Shah, R.R.; Garcia, R.E.; Jeffs, J.T.; Virden, J.W.; Heath, W.O.

1995-04-01

The High-Energy Corona (HEC) technology for treating process offgases has been under development at Pacific Northwest Laboratory (PNL) since 1991. The HEC process uses high-voltage electrical discharges in air to ionize the air, forming a low-temperature plasma that would be expected to destroy a wide variety of organic compounds in air. The plasma contains strong oxidants, possibly including hydroxyl radicals, hydroperoxy radicals, superoxide radicals, various excited as well as ionized forms of oxygen, high-energy electrons, and ultraviolet (UV) light. Because the high-voltage plasma is produced near ambient temperatures and pressures, yet exhibits extremely rapid destruction kinetics with relatively low power requirements, the HEC technique appears promising as a low-cost treatment technique (Virden et al. 1992). As part of the Volatile Organic Compound (VOC) Nonarid Integrated Demonstration (ID) at the DOE Savannah River Site, research activities were initiated in December 1991 to develop a prototype HEC process for a small-scale field demonstration to treat a soil-offgas stream contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) at varying concentrations. Over an 18-month period, the HEC technology was developed on a fast track, through bench and pilot scales into a trailer-mounted system that was tested at the Nonarid ID. Other national laboratories, universities, and private companies have also participated at the Nonarid ID to demonstrate a number of conventional, emerging and innovative approaches for treating the same soil-offgas stream

The effect of coronae on leader initiation and development under thunderstorm conditions and in long air gaps

International Nuclear Information System (INIS)

Aleksandrov, N.L.; Bazelyan, E.M.; Carpenter Jr, R.B.; Drabkin, M.M.; Raizer, Yu P.

2001-01-01

The initiation and development of a leader is theoretically studied by considering an electrode which is embedded in a cloud of space charge injected by a corona discharge. The focus is on the initiation of upward lightning from a stationary grounded object in a thundercloud electric field. The main results are also applicable to the leader process in long laboratory air gaps at direct voltage. Simple physical models of non-stationary coronae developing in free space near a solitary stressed sphere and of a leader propagating in the space charge cloud of coronae are suggested. It is shown that the electric field redistribution due to the space charge released by the long corona discharge near the top of a high object hinders the initiation and development of an upward leader from the object in a thundercloud electric field. The conditions for the formation of corona streamers that are required to initiate a leader are derived. The criteria are obtained for a leader to be initiated and propagate in the space charge cloud. A hypothesis is proposed that the streamers are never initiated near the top of a high object under thunderstorm conditions if at ground level there is only a slowly-varying electric field of the thundercloud. The streamers may be induced by the fast-rising electric field of distant downward leaders or intracloud discharges. (author)

A Model for Periodic Nonlinear Electric Field Structures in Space Plasmas

International Nuclear Information System (INIS)

Qureshi, M.N.S.; Shi Jiankui; Liu Zhenxing

2009-01-01

In this study, we present a physical model to explain the generation mechanism of nonlinear periodic waves with a large amplitude electric field structures propagating obliquely and exactly parallel to the magnetic field. The 'Sagdeev potential' from the MHD equations is derived and the nonlinear electric field waveforms are obtained when the Mach number, direction of propagation, and the initial electric field satisfy certain plasma conditions. For the parallel propagation, the amplitude of the electric field waves with ion-acoustic mode increases with the increase of initial electric field and Mach number but its frequency decreases with the increase of Mach number. The amplitude and frequency of the electric field waves with ion-cyclotron mode decrease with the increase of Mach number and become less spiky, and its amplitude increases with the increase of initial electric field. For the oblique propagation, only periodic electric field wave with an ion-cyclotron mode obtained, its amplitude and frequency increase with the increase of Mach number and become spiky. From our model the electric field structures show periodic, spiky, and saw-tooth behaviours corresponding to different plasma conditions.

Field-Metered Data from Portable Unit Dehumidifiers in the U.S. Residential Sector: Initial Results of a Pilot Study

Energy Technology Data Exchange (ETDEWEB)

Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Beraki, Bereket [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Burke, Tom [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Melody, Moya [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Nagaraju, Mythri [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Ni, Chun Chun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Pratt, Stacy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Dominique Yang, Hung-Chia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division

2013-01-29

The work described herein is intended to enrich the body of literature regarding dehumidifiers in residential settings—in particular the hours of use and energy consumption of various types of dehumidifiers. In the United States, portable unit dehumidifiers most commonly are used in basements during humid summer days in northern climates. Dehumidifier energy consumption differs among households depending on settings selected by the user, frequency of use, and conditions of operation. Although some estimates of dehumidifier use have been developed, and a few metering studies performed, there remains a paucity of metered data collected from individual households that use dehumidifiers. For this study we obtained field data on the energy consumption of dehumidifiers to supplement currently available analyses. Our goal was to obtain data from a pilot study that we could use to develop initial distributions describing the capacities and applications of dehumidifiers used in individual homes. More precisely characterizing the use of dehumidifiers in real-world applications will enable a more accurate estimate of the range of energy use in various operational modes. Our pilot field-metering exercise was aimed at compiling real-time data on the energy consumption of portable dehumidifiers in residential households in the New England and Mid-Atlantic areas. Our analysis furthers the process of developing a more precise estimate of dehumidifier energy use, which will support the evaluation of the potential energy savings and attendant costs associated with more energy efficient dehumidifiers.

Existence of solutions for Hamiltonian field theories by the Hamilton-Jacobi technique

International Nuclear Information System (INIS)

Bruno, Danilo

2011-01-01

The paper is devoted to prove the existence of a local solution of the Hamilton-Jacobi equation in field theory, whence the general solution of the field equations can be obtained. The solution is adapted to the choice of the submanifold where the initial data of the field equations are assigned. Finally, a technique to obtain the general solution of the field equations, starting from the given initial manifold, is deduced.

Channel-closing effects in strong-field ionization by a bicircular field

Science.gov (United States)

Milošević, D. B.; Becker, W.

2018-03-01

Channel-closing effects, such as threshold anomalies and resonantlike intensity-dependent enhancements in strong-field ionization by a bicircular laser field are analyzed. A bicircular field consists of two coplanar corotating or counter-rotating circularly polarized fields having different frequencies. For the total detachment rate of a negative ion by a bicircular field we observe threshold anomalies and explain them using the Wigner threshold law and energy and angular momentum conservation. For the corotating bicircular case, these effects are negligible, while for the counter-rotating case they are pronounced and their position depends on the magnetic quantum number of the initial state. For high-order above-threshold ionization of rare-gas atoms by a counter-rotating bicircular laser field we observe very pronounced intensity-dependent enhancements. We find all four types of threshold anomalies known from collision theory. Contrary to the case of linear polarization, channel-closing effects for a bicircular field are visible also in the cutoff region of the electron energy spectrum, which is explained using quantum-orbit theory.

Time independent mean-field theory

International Nuclear Information System (INIS)

Negele, J.W.

1980-02-01

The physical and theoretical motivations for the time-dependent mean-field theory are presented, and the successes and limitations of the time-dependent Hartree-Fock initial-vaue problem are reviewed. New theoretical developments are described in the treatment of two-body correlations and the formulation of a quantum mean-field theory of large-amplitude collective motion and tunneling decay. Finally, the mean-field theory is used to obtain new insights into the phenomenon of pion condensation in finite nuclei. 18 figures

Influence of error fields on the plasma confining field and the plasma confinement in tokamak

International Nuclear Information System (INIS)

Matsuda, Shinzaburo

1977-05-01

Influence of error fields on the plasma confining field and the plasma confinement is treated in the standpoint of design. In the initial breakdown phase before formation of the closed magnetic surfaces, the vertical field properly applied is the most important. Once the magnetic surfaces are formed, the non-axisymmetric error field is important. Effect of the shell gap associated with iron core and with pulsed vertical coils is thus studied. The formation of magnetic islands due to the external non-axisymmetric error field is studied with a simple model. A method of suppressing the islands by choosing the minor periodicity is proposed. (auth.)

On crack initiation in notched, cross-plied polymer matrix composites

Science.gov (United States)

Yang, Q. D.; Schesser, D.; Niess, M.; Wright, P.; Mavrogordato, M. N.; Sinclair, I.; Spearing, S. M.; Cox, B. N.

2015-05-01

The physics of crack initiation in a polymer matrix composite are investigated by varying the modeling choices made in simulations and comparing the resulting predictions with high-resolution in situ images of cracks. Experimental data were acquired using synchrotron-radiation computed tomography (SRCT) at a resolution on the order of 1 μm, which provides detailed measurement of the location, shape, and size of small cracks, as well as the crack opening and shear displacements. These data prove sufficient to discriminate among competing physical descriptions of crack initiation. Simulations are executed with a high-fidelity formulation, the augmented finite element method (A-FEM), which permits consideration of coupled damage mechanisms, including both discrete cracks and fine-scale continuum damage. The discrete cracks are assumed to be nonlinear fracture events, governed by reasonably general mixed-mode cohesive laws. Crack initiation is described in terms of strength parameters within the cohesive laws, so that the cohesive law provides a unified model for crack initiation and growth. Whereas the cracks investigated are typically 1 mm or less in length, the fine-scale continuum damage refers to irreversible matrix deformation occurring over gauge lengths extending down to the fiber diameter (0.007 mm). We find that the location and far-field stress for crack initiation are predicted accurately only if the variations of local stress within plies and in the presence of stress concentrators (notches, etc.) are explicitly computed and used in initiation criteria; stress redistribution due to matrix nonlinearity that occurs prior to crack initiation is accounted for; and a mixed-mode criterion is used for crack initiation. If these factors are not all considered, which is the case for commonly used failure criteria, predictions of the location and far-field stress for initiation are not accurate.

Regularity of solutions of a phase field model

KAUST Repository

Amler, Thomas

2013-01-01

Phase field models are widely-used for modelling phase transition processes such as solidification, freezing or CO2 sequestration. In this paper, a phase field model proposed by G. Caginalp is considered. The existence and uniqueness of solutions are proved in the case of nonsmooth initial data. Continuity of solutions with respect to time is established. In particular, it is shown that the governing initial boundary value problem can be considered as a dynamical system. © 2013 International Press.

Scalar field dark matter and the Higgs field

Directory of Open Access Journals (Sweden)

O. Bertolami

2016-08-01

Full Text Available We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10−6–10−4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall–Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.

The US proliferation security initiative (PSI); L'initiative americaine de securite contre la proliferation (PSI)

Energy Technology Data Exchange (ETDEWEB)

Gregoire, B

2004-10-01

The proliferation security initiative (PSI), launched by President Bush on May 31, 2003, aims at intercepting any transfer of mass destruction weapons, of their vectors and related equipments, towards or coming from countries or organizations suspected to have a proliferation activity. This initiative, which involves coercive means to fight against proliferation, raises international lawfulness and legal questions, the answers of which are today under construction. This article analyzes the place of the European Union in the PSI, the action means (optimization of existing means, cooperation between intelligence and interception services), and the PSI stakes (lawfulness with respect to the international law, bilateral agreements, draft boarding agreement, sustain of the United Nations, widening of the partnership and of the field of action). (J.S.)

Intraoperative Scintigraphy Using a Large Field-of-View Portable Gamma Camera for Primary Hyperparathyroidism: Initial Experience

Directory of Open Access Journals (Sweden)

Nathan C. Hall

2015-01-01

Full Text Available Background. We investigated a novel technique, intraoperative 99 mTc-Sestamibi (MIBI imaging (neck and excised specimen (ES, using a large field-of-view portable gamma camera (LFOVGC, for expediting confirmation of MIBI-avid parathyroid adenoma removal. Methods. Twenty patients with MIBI-avid parathyroid adenomas were preoperatively administered MIBI and intraoperatively imaged prior to incision (neck and immediately following resection (neck and/or ES. Preoperative and intraoperative serum parathyroid hormone monitoring (IOPTH and pathology (path were also performed. Results. MIBI neck activity was absent and specimen activity was present in 13/20 with imaging after initial ES removal. In the remaining 7/20 cases, residual neck activity and/or absent ES activity prompted excision of additional tissue, ultimately leading to complete hyperfunctioning tissue excision. Postexcision LFOVGC ES imaging confirmed parathyroid adenoma resection 100% when postresection imaging qualitatively had activity (ES and/or no activity (neck. The mean ± SEM time saving using intraoperative LFOVGC data to confirm resection versus first IOPTH or path result would have been 22.0 ± 2 minutes (specimen imaging and 26.0 ± 3 minutes (neck imaging. Conclusion. Utilization of a novel real-time intraoperative LFOVGC imaging approach can provide confirmation of MIBI-avid parathyroid adenoma removal appreciably faster than IOPTH and/or path and may provide a valuable adjunct to parathyroid surgery.

SIMULATING MAGNETIC FIELDS IN THE ANTENNAE GALAXIES

International Nuclear Information System (INIS)

Kotarba, H.; Karl, S. J.; Naab, T.; Johansson, P. H.; Lesch, H.; Dolag, K.; Stasyszyn, F. A.

2010-01-01

We present self-consistent high-resolution simulations of NGC 4038/4039 (the A ntennae galaxies ) including star formation, supernova feedback, and magnetic fields performed with the N-body/smoothed particle hydrodynamic (SPH) code GADGET, in which magnetohydrodynamics are followed with the SPH method. We vary the initial magnetic field in the progenitor disks from 10 -9 to 10 -4 G. At the time of the best match with the central region of the Antennae system, the magnetic field has been amplified by compression and shear flows to an equilibrium field value of ∼10 μG, independent of the initial seed field. These simulations are a proof of the principle that galaxy mergers are efficient drivers for the cosmic evolution of magnetic fields. We present a detailed analysis of the magnetic field structure in the central overlap region. Simulated radio and polarization maps are in good morphological and quantitative agreement with the observations. In particular, the two cores with the highest synchrotron intensity and ridges of regular magnetic fields between the cores and at the root of the southern tidal arm develop naturally in our simulations. This indicates that the simulations are capable of realistically following the evolution of the magnetic fields in a highly nonlinear environment. We also discuss the relevance of the amplification effect for present-day magnetic fields in the context of hierarchical structure formation.

Assessment of field training for nuclear operations personnel

Energy Technology Data Exchange (ETDEWEB)

White, M [Safety Management Services, Inc. (Canada)

1995-08-01

Training of station personnel is an important component of the safe operation of the nuclear generating station. On-the-job training (OJT) is an important component of training. The AECB initiated this project to develop a process to assess the effectiveness of OJT for field operators, and perform an initial trial of the developed process. This report describes the recommended process to assess the effectiveness of OJT for field operators, as well as the results of the initial assessment at Pickering Nuclear Generating Station. The assessment`s conclusions included: (1) Ontario Hydro policies and procedures are generally consistent with industry guidelines requiring a systematic approach to training; (2) Pickering NGS field operator performance is not always consistent with documented station requirements and standards, nor industry guidelines and practices; and (3) The Pickering NGS field operator on-the-job training is not consistent with a systematic approach to training, a requirement recognized in Ontario Hydro`s Policy NGD 113, and does not contribute to a high level of performance in field operator tasks. Recommendations are made regarding the use of the developed process for future assessments of on-the-job training at nuclear power plants. (author). 36 refs., 4 tabs., 3 figs.

Generation of a field development plan, North Field, North Oman

International Nuclear Information System (INIS)

Bostock, D.R.; Adams, S.; Mercadier, C.; Milatz, H.; van der Weerd, H.; Walker, T.

1991-01-01

This paper reports on the Natih Field in North Oman which is a complex domal fractured limestone structure with a STOIIP of some 50 million m 3 . Initially subjected to a depletion drive, rapidly dropping pressures resulted in a switch to water injection and then to gas injection to promote gas oil gravity drainage. In determining which production mechanism to promote an integrated approach has been taken. Field tests used tracers to investigate the problems associated with water injection; fracture orientation and intensity has been determined using core data including palaeomagnetics, FMS logs and out-crop studies; initial oil saturations have been determined within a give range using resistivity and pulsed neutron logs as well as capillary pressure curves to overcome problems of mixed wettability; to monitor gas saturation development in the matrix recourse has been made to Borehole Gravity Meter; special core analysis on restored state cores has been utilized to characterize wettability and relative permeability as input to both monitoring the water influx and to reservoir simulation. Development of a simulator to incorporate all the necessary physics of gravity drainage, including block to block interaction, has been undertaken at the research laboratories in the Netherlands and, using the understanding of the field built up through the above studies, a successful history match was achieved

Performance evaluation of parallel electric field tunnel field-effect transistor by a distributed-element circuit model

Science.gov (United States)

Morita, Yukinori; Mori, Takahiro; Migita, Shinji; Mizubayashi, Wataru; Tanabe, Akihito; Fukuda, Koichi; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shin-ichi; Liu, Yongxun; Masahara, Meishoku; Ota, Hiroyuki

2014-12-01

The performance of parallel electric field tunnel field-effect transistors (TFETs), in which band-to-band tunneling (BTBT) was initiated in-line to the gate electric field was evaluated. The TFET was fabricated by inserting an epitaxially-grown parallel-plate tunnel capacitor between heavily doped source wells and gate insulators. Analysis using a distributed-element circuit model indicated there should be a limit of the drain current caused by the self-voltage-drop effect in the ultrathin channel layer.

Next generation initiation techniques

Science.gov (United States)

Warner, Tom; Derber, John; Zupanski, Milija; Cohn, Steve; Verlinde, Hans

1993-01-01

Four-dimensional data assimilation strategies can generally be classified as either current or next generation, depending upon whether they are used operationally or not. Current-generation data-assimilation techniques are those that are presently used routinely in operational-forecasting or research applications. They can be classified into the following categories: intermittent assimilation, Newtonian relaxation, and physical initialization. It should be noted that these techniques are the subject of continued research, and their improvement will parallel the development of next generation techniques described by the other speakers. Next generation assimilation techniques are those that are under development but are not yet used operationally. Most of these procedures are derived from control theory or variational methods and primarily represent continuous assimilation approaches, in which the data and model dynamics are 'fitted' to each other in an optimal way. Another 'next generation' category is the initialization of convective-scale models. Intermittent assimilation systems use an objective analysis to combine all observations within a time window that is centered on the analysis time. Continuous first-generation assimilation systems are usually based on the Newtonian-relaxation or 'nudging' techniques. Physical initialization procedures generally involve the use of standard or nonstandard data to force some physical process in the model during an assimilation period. Under the topic of next-generation assimilation techniques, variational approaches are currently being actively developed. Variational approaches seek to minimize a cost or penalty function which measures a model's fit to observations, background fields and other imposed constraints. Alternatively, the Kalman filter technique, which is also under investigation as a data assimilation procedure for numerical weather prediction, can yield acceptable initial conditions for mesoscale models. The

Massive scalar field evolution in de Sitter

Energy Technology Data Exchange (ETDEWEB)

Markkanen, Tommi [Department of Physics, King’s College London,Strand, London WC2R 2LS (United Kingdom); Rajantie, Arttu [Department of Physics, Imperial College London,London SW7 2AZ (United Kingdom)

2017-01-30

The behaviour of a massive, non-interacting and non-minimally coupled quantised scalar field in an expanding de Sitter background is investigated by solving the field evolution for an arbitrary initial state. In this approach there is no need to choose a vacuum in order to provide a definition for particle states, nor to introduce an explicit ultraviolet regularization. We conclude that the expanding de Sitter space is a stable equilibrium configuration under small perturbations of the initial conditions. Depending on the initial state, the energy density can approach its asymptotic value from above or below, the latter of which implies a violation of the weak energy condition. The backreaction of the quantum corrections can therefore lead to a phase of super-acceleration also in the non-interacting massive case.

Emission Spectrum Property of Modulated Atom-Field Coupling System

International Nuclear Information System (INIS)

Gao Yun-Feng; Feng Jian; Li Yue-Ke

2013-01-01

The emission spectrum of a two-level atom interacting with a single mode radiation field in the case of periodic oscillation coupling coefficient is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in pure number stare are calculated. It is found that the effect of the coupling coefficient modulation on the spectral structure is very obvious in the case of a low modulation frequency and larger amplitude when the initial field is vacuum, which is potentially useful for exploring a modulated light source. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Evaluation of initial collector field performance at the Langley Solar Building Test Facility

Science.gov (United States)

Boyle, R. J.; Knoll, R. H.; Jensen, R. N.

1977-01-01

The thermal performance of the solar collector field for the NASA Langley Solar Building Test Facility is given for October 1976 through January 1977. An 1180 square meter solar collector field with seven collector designs helped to provide hot water for the building heating system and absorption air conditioner. The collectors were arranged in 12 rows with nominally 51 collectors per row. Heat transfer rates for each row are calculated and recorded along with sensor, insolation, and weather data every 5 minutes using a mini-computer. The agreement between the experimental and predicted collector efficiencies was generally within five percentage points.

The US proliferation security initiative (PSI)

International Nuclear Information System (INIS)

Gregoire, B.

2004-01-01

The proliferation security initiative (PSI), launched by President Bush on May 31, 2003, aims at intercepting any transfer of mass destruction weapons, of their vectors and related equipments, towards or coming from countries or organizations suspected to have a proliferation activity. This initiative, which involves coercive means to fight against proliferation, raises international lawfulness and legal questions, the answers of which are today under construction. This article analyzes the place of the European Union in the PSI, the action means (optimization of existing means, cooperation between intelligence and interception services), and the PSI stakes (lawfulness with respect to the international law, bilateral agreements, draft boarding agreement, sustain of the United Nations, widening of the partnership and of the field of action). (J.S.)

Information loss in effective field theory: Entanglement and thermal entropies

Science.gov (United States)

Boyanovsky, Daniel

2018-03-01

Integrating out high energy degrees of freedom to yield a low energy effective field theory leads to a loss of information with a concomitant increase in entropy. We obtain the effective field theory of a light scalar field interacting with heavy fields after tracing out the heavy degrees of freedom from the time evolved density matrix. The initial density matrix describes the light field in its ground state and the heavy fields in equilibrium at a common temperature T . For T =0 , we obtain the reduced density matrix in a perturbative expansion; it reveals an emergent mixed state as a consequence of the entanglement between light and heavy fields. We obtain the effective action that determines the time evolution of the reduced density matrix for the light field in a nonperturbative Dyson resummation of one-loop correlations of the heavy fields. The Von-Neumann entanglement entropy associated with the reduced density matrix is obtained for the nonresonant and resonant cases in the asymptotic long time limit. In the nonresonant case the reduced density matrix displays an incipient thermalization albeit with a wave-vector, time and coupling dependent effective temperature as a consequence of memory of initial conditions. The entanglement entropy is time independent and is the thermal entropy for this effective, nonequilibrium temperature. In the resonant case the light field fully thermalizes with the heavy fields, the reduced density matrix loses memory of the initial conditions and the entanglement entropy becomes the thermal entropy of the light field. We discuss the relation between the entanglement entropy ultraviolet divergences and renormalization.

Computing discrete signed distance fields from triangle meshes

DEFF Research Database (Denmark)

Bærentzen, Jakob Andreas; Aanæs, Henrik

2002-01-01

A method for generating a discrete, signed 3D distance field is proposed. Distance fields are used in a number of contexts. In particular the popular level set method is usually initialized by a distance field. The main focus of our work is on simplifying the computation of the sign when generating...

The oil field chemists role during field abandonment

Energy Technology Data Exchange (ETDEWEB)

Read, P.A.; Alfsnes, K.

1996-12-31

During the next ten years an increasing number of redundant oil and gas production facilities are scheduled for decommissioning on the Norwegian continental shelf. The oil field chemists role in this connection is discussed. Many of the facilities are large combined drilling and production platforms, others no more than field control centres. Their construction materials and methods are very varied, ranging from steel jackets to concrete gravity structures. Many sub sea templates and flow lines will be targeted for removal. An initial review of a simple production platform has revealed the presence of almost 800 chemical substances. The environmental fate of the materials is needed for estimating the best possible environmental option for the disposal of installations and their contents

Local fields and their extensions

CERN Document Server

Fesenko, I B

2002-01-01

This book offers a modern presentation of local fields whose spectacular development was initiated almost one hundred years ago by K. Hensel. The volume consists of nine chapters divided into four parts: arithmetic properties of local fields, class field theory for various types of local fields and generalizations, explicit formulas for the Hilbert pairing, and Milnor K-groups of fields and of local fields. The first three parts essentially simplify, revise, and update the first edition. This second edition contains about sixty additional pages reflecting several aspects of the developments in local number theory in the last ten years. Exercises point to many other paths for exploration. The book is designed for graduate students and research mathematicians interested in local number theory and its applications in arithmetic algebraic geometry.

Cross-validated detection of crack initiation in aerospace materials

Science.gov (United States)

Vanniamparambil, Prashanth A.; Cuadra, Jefferson; Guclu, Utku; Bartoli, Ivan; Kontsos, Antonios

2014-03-01

A cross-validated nondestructive evaluation approach was employed to in situ detect the onset of damage in an Aluminum alloy compact tension specimen. The approach consisted of the coordinated use primarily the acoustic emission, combined with the infrared thermography and digital image correlation methods. Both tensile loads were applied and the specimen was continuously monitored using the nondestructive approach. Crack initiation was witnessed visually and was confirmed by the characteristic load drop accompanying the ductile fracture process. The full field deformation map provided by the nondestructive approach validated the formation of a pronounced plasticity zone near the crack tip. At the time of crack initiation, a burst in the temperature field ahead of the crack tip as well as a sudden increase of the acoustic recordings were observed. Although such experiments have been attempted and reported before in the literature, the presented approach provides for the first time a cross-validated nondestructive dataset that can be used for quantitative analyses of the crack initiation information content. It further allows future development of automated procedures for real-time identification of damage precursors including the rarely explored crack incubation stage in fatigue conditions.

Magnetic field propagation in a two ion species planar plasma opening switch

International Nuclear Information System (INIS)

Strauss, H. R.; Doron, R.; Arad, R.; Rubinstein, B.; Maron, Y.; Fruchtman, A.

2007-01-01

Three fluid plasma evolution equations are applied to the problem of magnetic field propagation in a planar plasma opening switch. For certain initial conditions in which Hall parameter H∼1, magnetic field penetration due to the Hall field, initially, as expected, either opposes or adds to the hydromagnetic pushing, depending on the polarity of the magnetic field relative to the density gradient. Later, however, the plasma pushing by the magnetic field is found in the case studied here to modify the plasma density in a way that the density gradient tends to align with the magnetic field gradient, effectively turning off the Hall effect. The penetration of the magnetic field then ceases and plasma pushing becomes the dominant process

The p53 codon 72 PRO/PRO genotype may be associated with initial central visual field defects in caucasians with primary open angle glaucoma.

Directory of Open Access Journals (Sweden)

Janey L Wiggs

Full Text Available Loss of vision in glaucoma is due to apoptotic retinal ganglion cell loss. While p53 modulates apoptosis, gene association studies between p53 variants and glaucoma have been inconsistent. In this study we evaluate the association between a p53 variant functionally known to influence apoptosis (codon 72 Pro/Arg and the subset of primary open angle glaucoma (POAG patients with early loss of central visual field.Genotypes for the p53 codon 72 polymorphism (Pro/Arg were obtained for 264 POAG patients and 400 controls from the U.S. and in replication studies for 308 POAG patients and 178 controls from Australia (GIST. The glaucoma patients were divided into two groups according to location of initial visual field defect (either paracentral or peripheral. All cases and controls were Caucasian with European ancestry.The p53-PRO/PRO genotype was more frequent in the U.S. POAG patients with early visual field defects in the paracentral regions compared with those in the peripheral regions or control group (p=2.7 × 10(-5. We replicated this finding in the GIST cohort (p  =7.3 × 10(-3, and in the pooled sample (p=6.6 × 10(-7 and in a meta-analysis of both the US and GIST datasets (1.3 × 10(-6, OR 2.17 (1.58-2.98 for the PRO allele.These results suggest that the p53 codon 72 PRO/PRO genotype is potentially associated with early paracentral visual field defects in primary open-angle glaucoma patients.

Initial behavior of a quantized scalar field and the associated pair-creation in several isotropic closed and open universes

International Nuclear Information System (INIS)

Nariai, Hidekazu.

1981-01-01

The concept of a positive frequency part near the initial epoch in a big-bang universe or its counterpart in other (say, de Sitter) one for a canonically quantized scalar field is important in discussing the associated pair-creation of those particles. Therefore, an attempt is made to define the positive frequency part in such isotropic closed and open universes that the scalar wave equation can be exactly solved. Except for some closed universe, the parts in question and, therefore, the Feynman propagators in the remaining universes are uniquely settled. Then it is shown that (1) the pair-creation in the Friedmann open universe (which is very interesting not only from observational, but also from theoretical viewpoints) is essentially equivalent to that in the Chitre-Hartle universe with flat 3-space and (2) the respective pair-creations in expanding metrics with open and flat 3-spaces of the de Sitter universe are different from each other, as insisted upon by Gibbons and Hawking basing on the original static metric. (author)

Initial behavior of a quantized scalar field and the associated pair-creation in several isotropic closed and open universes

International Nuclear Information System (INIS)

Nariai, Hidekazu

1982-01-01

The concept of a positive frequency part near the initial epoch in a big-bang universe or its counterpart in other (say, de Sitter) one for a canonically quantized scalar field is important in discussing the associated pair-creation of those particles. Therefore, an attempt is made to define the positive frequency part in such isotropic closed and open universes that the scalar wave equation can be exactly solved. Except for some closed universe, the parts in question and, therefore, the Feynman propagators in the remaining universes are uniquely settled. Then it is shown that (1) the pair-creation in the Friedmann open universe (which is very interesting not only from observational, but also from theoretical viewpoints) is essentially equivalent to that in the Chitre-Hartle universe with flat 3-space and (2) the respective pair-creations in expanding metrics with open and flat 3-spaces of the de Sitter universe are different from each other, as insisted upon by Gibbons and Hawking basing on the original static metric. (author)

Overlay control methodology comparison: field-by-field and high-order methods

Science.gov (United States)

Huang, Chun-Yen; Chiu, Chui-Fu; Wu, Wen-Bin; Shih, Chiang-Lin; Huang, Chin-Chou Kevin; Huang, Healthy; Choi, DongSub; Pierson, Bill; Robinson, John C.

2012-03-01

Overlay control in advanced integrated circuit (IC) manufacturing is becoming one of the leading lithographic challenges in the 3x and 2x nm process nodes. Production overlay control can no longer meet the stringent emerging requirements based on linear composite wafer and field models with sampling of 10 to 20 fields and 4 to 5 sites per field, which was the industry standard for many years. Methods that have emerged include overlay metrology in many or all fields, including the high order field model method called high order control (HOC), and field by field control (FxFc) methods also called correction per exposure. The HOC and FxFc methods were initially introduced as relatively infrequent scanner qualification activities meant to supplement linear production schemes. More recently, however, it is clear that production control is also requiring intense sampling, similar high order and FxFc methods. The added control benefits of high order and FxFc overlay methods need to be balanced with the increased metrology requirements, however, without putting material at risk. Of critical importance is the proper control of edge fields, which requires intensive sampling in order to minimize signatures. In this study we compare various methods of overlay control including the performance levels that can be achieved.

Blasting agents and initiation systems

Energy Technology Data Exchange (ETDEWEB)

Fiscor, S.

2000-01-01

Although blasting differs between and within each industry, as a whole, the mines and quarries are making a shift from a purely ammonium nitrate/fuel oil (ANFO) mixture to a blend of emulsion and ANFO on a straight emulsion. Non-electric (shock tube) initiation systems have provided a viable alternative to the electric detonator (blasting cap). Explosives manufacturers are seeing their roles changes to being blasting contractors or consultants rather than just suppliers. The article discusses these trends and gives examples of typical blasting techniques and amounts of blasting agent used at large USA surface coal mines. Electric caps are still used in blasting underground coal. The Ensign Bickford Co. (EBCo) is developing electronic detonators and has been field testing an electronic initiator, the DIGIDET detonator, for the last four years. When commercially available, electronic detonators will be accurate but will come with a hefty price tag. 2 photos.

South American Field Experience: An Initiative in International Education. The Implementation Journal for the South American Field Experience.

Science.gov (United States)

Martin, William J.

A description is provided of Williamsport Area Community College's (WACC's) South American Field Experience program, a travel/study program for faculty and staff designed to provide a variety of learning experiences through a three week trip to Peru, Chile, Argentina, and Brazil. Chapter I presents an overview of the development of the project,…

Initial assessments of ignition spherical torus

International Nuclear Information System (INIS)

Peng, Y.K.M.; Borowski, S.K.; Bussell, G.T.

1985-12-01

Initial assessments of ignition spherical tori suggest that they can be highly cost effective and exceptionally small in unit size. Assuming advanced methods of current drive to ramp up the plasma current (e.g., via lower hybrid wave at modest plasma densities and temperatures), the inductive solenoid can largely be eliminated. Given the uncertainties in plasma energy confinement times and the effects of strong paramagnetism on plasma pressure, and allowing for the possible use of high-strength copper alloys (e.g., C-17510, Cu-Ni-Be alloy), ignition spherical tori with a 50-s burn are estimated to have major radii ranging from 1.0 to 1.6 m, aspect ratios from 1.4 to 1.7, vacuum toroidal fields from 2 to 3 T, plasma currents from 10 to 19 MA, and fusion power from 50 to 300 MW. Because of its modest field strength and simple poloidal field coil configuration, only conventional engineering approaches are needed in the design. A free-standing toroidal field coil/vacuum vessel structure is assessed to be feasible and relatively independent of the shield structure and the poloidal field coils. This exceptionally simple configuration depends significantly, however, on practical fabrication approaches of the center conductor post, about which there is presently little experience. 19 refs

arXiv Initial Conditions for Critical Higgs Inflation

CERN Document Server

Salvio, Alberto

2018-05-10

It has been pointed out that a large non-minimal coupling ξ between the Higgs and the Ricci scalar can source higher derivative operators, which may change the predictions of Higgs inflation. A variant, called critical Higgs inflation, employs the near-criticality of the top mass to introduce an inflection point in the potential and lower drastically the value of ξ . We here study whether critical Higgs inflation can occur even if the pre-inflationary initial conditions do not satisfy the slow-roll behavior (retaining translation and rotation symmetries). A positive answer is found: inflation turns out to be an attractor and therefore no fine-tuning of the initial conditions is necessary. A very large initial Higgs time-derivative (as compared to the potential energy density) is compensated by a moderate increase in the initial field value. These conclusions are reached by solving the exact Higgs equation without using the slow-roll approximation. This also allows us to consistently treat the inflection poi...

Entropy squeezing of the field interacting with a nearly degenerate V-type three-level atom

Institute of Scientific and Technical Information of China (English)

Zhou Qing-Chun; Zhu Shi-Ning

2005-01-01

The position- and momentum-entopic squeezing properties of the optical field in the system of a nearly degenerate three-level atom interacting with a single-mode field are investigated. Calculation results indicate that when the field is initially in the vacuum state, it may lead to squeezing of the position entropy or the momentum entropy of the field if the atom is prepared properly. The effects of initial atomic state and the splitting of the excited levels of the atom on field entropies are discussed in this case. When the initial field is in a coherent state, we find that position-entropy squeezing of the field is present even if the atom is prepared in the ground state. By comparing the variance squeezing and entropy squeezing of the field we confirm that entropy is more sensitive than variance in measuring quantum fluctuations.

Time dependence of the field energy densities surrounding sources: Application to scalar mesons near point sources and to electromagnetic fields near molecules

International Nuclear Information System (INIS)

Persico, F.; Power, E.A.

1987-01-01

The time dependence of the dressing-undressing process, i.e., the acquiring or losing by a source of a boson field intensity and hence of a field energy density in its neighborhood, is considered by examining some simple soluble models. First, the loss of the virtual field is followed in time when a point source is suddenly decoupled from a neutral scalar meson field. Second, an initially bare point source acquires a virtual meson cloud as the coupling is switched on. The third example is that of an initially bare molecule interacting with the vacuum of the electromagnetic field to acquire a virtual photon cloud. In all three cases the dressing-undressing is shown to take place within an expanding sphere of radius r = ct centered at the source. At each point in space the energy density tends, for large times, to that of the ground state of the total system. Differences in the time dependence of the dressing between the massive scalar field and the massless electromagnetic field are discussed. The results are also briefly discussed in the light of Feinberg's ideas on the nature of half-dressed states in quantum field theory

A regularization method for extrapolation of solar potential magnetic fields

Science.gov (United States)

Gary, G. A.; Musielak, Z. E.

1992-01-01

The mathematical basis of a Tikhonov regularization method for extrapolating the chromospheric-coronal magnetic field using photospheric vector magnetograms is discussed. The basic techniques show that the Cauchy initial value problem can be formulated for potential magnetic fields. The potential field analysis considers a set of linear, elliptic partial differential equations. It is found that, by introducing an appropriate smoothing of the initial data of the Cauchy potential problem, an approximate Fourier integral solution is found, and an upper bound to the error in the solution is derived. This specific regularization technique, which is a function of magnetograph measurement sensitivities, provides a method to extrapolate the potential magnetic field above an active region into the chromosphere and low corona.

The start of lightning: Evidence of bidirectional lightning initiation.

Science.gov (United States)

Montanyà, Joan; van der Velde, Oscar; Williams, Earle R

2015-10-16

Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leaders. We report here a serendipitous recording of bidirectional lightning initiation in virgin air under the cloud base at ~11,000 images per second, and the differences in characteristics of opposite polarity leader sections during the earliest stages of the discharge. This case reveals natural lightning initiation, propagation and a return stroke as in negative cloud-to-ground flashes, upon connection to another lightning channel - without any masking by cloud.

Crack initiation under generalized plane strain conditions

International Nuclear Information System (INIS)

Shum, D.K.M.; Merkle, J.G.

1991-01-01

A method for estimating the decrease in crack-initiation toughness, from a reference plane strain value, due to positive straining along the crack front of a circumferential flaw in a reactor pressure vessel is presented in this study. This method relates crack initiation under generalized plane strain conditions with material failure at points within a distance of a few crack-tip-opening displacements ahead of a crack front, and involves the formulation of a micromechanical crack-initiation model. While this study is intended to address concerns regarding the effects of positive out-of- plane straining on ductile crack initiation, the approach adopted in this work can be extended in a straightforward fashion to examine conditions of macroscopic cleavage crack initiation. Provided single- parameter dominance of near-tip fields exists in the flawed structure, results from this study could be used to examine the appropriateness of applying plane strain fracture toughness to the evaluation of circumferential flaws, in particular to those in ring-forged vessels which have no longitudinal welds. In addition, results from this study could also be applied toward the analysis of the effects of thermal streaming on the fracture resistance of circumferentially oriented flaws in a pressure vessel. 37 refs., 8 figs., 1 tab

Initial thermal state of the Los Humeros, Puebla, Mexico, geothermal field; Estado termico inicial del campo geotermico de Los Humeros, Puebla, Mexico

Energy Technology Data Exchange (ETDEWEB)

Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: aggarcia@iie.org.mx

2009-01-15

The initial temperatures field is presented for 40 wells in the Los Humeros geothermal reservoir, along with an elevation curve based on the formation temperature or the most probable reservoir temperature. Stabilized temperatures were estimated using the Radial Spherical Heat Flow method, chosen over the Horner method based on the numerical simulation of the circulation and stop processes of well H-26. In this well, the last temperature log series was reproduced, considering circulation losses. The temperatures were used to produce isothermal curves over three geological sections of the field, which represent the initial distribution of temperatures in the reservoir and show the thermal characteristics and the relationships among thermal anomalies and faults in the reservoir. The elevation curve plotted against the initial temperature of the formation was generated based on detection of the main feed zones at each well, which in turn was developed using detailed analyses of diverse information, such as temperature logs, circulation losses, lithology, well completion, and heat velocities. Based on the results, two groups of wells may be distinguished: one between 1000 and 1600 masl with temperatures from 290 to 330 degrees Celsius, and one between 900 and 0 masl with temperatures from 300 to 400 degrees Celsius. [Spanish] En este trabajo se presenta el campo de temperatura inicial del yacimiento geotermico de Los Humeros y una curva de elevacion contra la temperatura de formacion o temperatura mas probable del yacimiento, obtenida para 40 pozos del campo. Las temperaturas estabilizadas se estimaron mediante el metodo de Flujo de Calor Esferico Radial, y su eleccion sobre las temperaturas del metodo de Horner se soporta con simulacion numerica de los procesos de circulacion y paro del pozo H-26, en la cual la ultima serie de registros se reprodujo considerando perdidas de circulacion. Con estas temperaturas se generaron curvas isotermicas para tres secciones

Initial temperature distribution in Los Humeros, Mexico, geothermal field; Distribucion de temperatura inicial en el campo geotermico de Los Humeros, Puebla

Energy Technology Data Exchange (ETDEWEB)

Garcia, A; Arellano, V; Aragon, A; Barragan, R.M; Izquierdo, G [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Pizano, A [Comision federal de Electricidad, Los Humeros, Puebla (Mexico)

2000-12-01

The initial formation temperatures surrounding 40 wells from the Los Humeros geothermal field are presented. These temperatures were estimated using the Horner and the sphere methods. A brief discussion on the applicability of each method is presented and previous applications are detailed. Then the more likely reservoir temperature of each well versus elevation is plotted based on the estimations about the main feed zone and the temperature of each well. The boiling with depth curve for pure water is also included. Two longitudinal and one traverse geological sections are presented to illustrate the field initial temperature distribution, the lithology and layers thickness, the basement topography and the wells traversed along each sections. Also, the main feed zones of the wells are indicated. Finally, the last series of measured temperature logs in well H-26 are produced by numerical simulation. This considers the well circulation losses and an assumed initial temperature profile. This profile iteratively modified until the computed profiles match the measured temperature profiles. The last assumed temperature profile is then considered as the best approximation to the undisturbed formation temperature around well H-26 and it is then compared with the stabilized temperatures obtained via the Horner and Sphere methods. [Spanish] Se presentan las temperaturas iniciales o estabilizadas de la formacion circundante a 40 pozos del campo geotermico Los Humeros, las cuales se estimaron mediante los metodos de Horner y el metodo de la esfera. Se presenta una discusion sobre la aplicacion de cada metodo y se detallan las aplicaciones previas del metodo de la esfera. Posteriormente y con base en las estimaciones de las principales zonas de aporte de cada pozo y sus correspondientes temperaturas se grafican las temperaturas mas probables de yacimiento para cada pozo contra la elevacion y se incluye en la misma grafica la curva de ebullicion del agua contra la elevacion. Se

On the hyperbolicity of Einstein's and other gauge field equations

International Nuclear Information System (INIS)

Friedrich, H.

1985-01-01

It is shown that Einstein's vacuum field equations (respectively the conformal vacuum field equations) in a frame formalism imply a symmetric hyperbolic system of ''reduce'' propagation equations for any choice of coordinate system and frame field (and conformal factor). Certain freely specifiable ''gauge source'' functions occurring in the reduced equations reflect the choice of gauge. Together with the initial data they determine the gauge uniquely. Their choice does not affect the isometry class (conformal class) of a solution of an initial value problem. By the same method symmetric hyperbolic propagation equations are obtained from other gauge field equations, irrespective of the gauge. Using the concept of source functions one finds that Einstein's field equation, considered as second order equations for the metric coefficients, are of wave equation type in any coordinate system. (orig.)

Particle-in-cell simulations of collisionless magnetic reconnection with a non-uniform guide field

International Nuclear Information System (INIS)

Wilson, F.; Neukirch, T.; Harrison, M. G.; Hesse, M.; Stark, C. R.

2016-01-01

Results are presented of a first study of collisionless magnetic reconnection starting from a recently found exact nonlinear force-free Vlasov–Maxwell equilibrium. The initial state has a Harris sheet magnetic field profile in one direction and a non-uniform guide field in a second direction, resulting in a spatially constant magnetic field strength as well as a constant initial plasma density and plasma pressure. It is found that the reconnection process initially resembles guide field reconnection, but that a gradual transition to anti-parallel reconnection happens as the system evolves. The time evolution of a number of plasma parameters is investigated, and the results are compared with simulations starting from a Harris sheet equilibrium and a Harris sheet plus constant guide field equilibrium.

Initial reversed-field pinch experiments on ZT-40 and recent advances in RFP theory

International Nuclear Information System (INIS)

Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

1980-01-01

The ZT-40 reversed-field pinch (RFP) has been operated in several modes: (1) without reversed toroidal field, (2) with self reversal, and (3) with aided reversal. An analytic ohmic heating and ignition model both confirm and provide guidance for transport codes. Nondissipative formation schemes have been analyzed and ideal MHD stable evolution and burn scenarios have been found. Particle and fluid simulations have produced qualitative agreement with respect to the nonlinear behavior of m = 0 resistive g-modes. Helical ohmic reversed field states are produced by a 2-D dynamical simulation, and nonlinear analytic work describes the final state. A fast resistive MHD code for linear stability has clarified the relations between several kinds of resistive instabilities. Ballooning modes and g-modes in systems with arbitrary magnetic shear including resistivity and viscosity, have been studied in a unified treatment with growth rate vs wavenumber showing the existence of important cutoffs

Effects of sub-domain structure on initial magnetization curve and domain size distribution of stacked media

International Nuclear Information System (INIS)

Sato, S.; Kumagai, S.; Sugita, R.

2015-01-01

In this paper, in order to confirm the sub-domain structure in stacked media demagnetized with in-plane field, initial magnetization curves and magnetic domain size distribution were investigated. Both experimental and simulation results showed that an initial magnetization curve for the medium demagnetized with in-plane field (MDI) initially rose faster than that for the medium demagnetized with perpendicular field (MDP). It is inferred that this is because the MDI has a larger number of domain walls than the MDP due to the existence of the sub-domains, resulting in an increase in the probability of domain wall motion. Dispersion of domain size for the MDI was larger than that for the MDP. This is because sub-domains are formed not only inside the domain but also at the domain boundary region, and they change the position of the domain boundary to affect the domain size. - Highlights: • An initial magnetization curve for MDI initially rose faster than that for MDP. • Dispersion of domain size for the MDI was larger than that for the MDP. • Experimental and simulation results can be explained by existence of sub-domains

Magnetic field induced dynamical chaos.

Science.gov (United States)

Ray, Somrita; Baura, Alendu; Bag, Bidhan Chandra

2013-12-01

In this article, we have studied the dynamics of a particle having charge in the presence of a magnetic field. The motion of the particle is confined in the x-y plane under a two dimensional nonlinear potential. We have shown that constant magnetic field induced dynamical chaos is possible even for a force which is derived from a simple potential. For a given strength of the magnetic field, initial position, and velocity of the particle, the dynamics may be regular, but it may become chaotic when the field is time dependent. Chaotic dynamics is very often if the field is time dependent. Origin of chaos has been explored using the Hamiltonian function of the dynamics in terms of action and angle variables. Applicability of the present study has been discussed with a few examples.

IAEA Technical Meeting on Status of IAEA Fast Reactor Knowledge Preservation Initiative. Presentations

International Nuclear Information System (INIS)

2013-01-01

The objectives of the technical meeting were to: • exchange information between the Member States/International Organizations on national and international initiatives addressing knowledge preservation and data retrieval/collection in the field of fast neutron systems; • present and discuss the Member States’/International Organizations’ policies and conditions for releasing to the IAEA both publicly available and confidential information on fast neutron systems; • collect data on fast neutron systems provided by participating Member States/International Organizations and encourage participants to contribute in data collection; • provide recommendations for further IAEA initiatives in the field of fast reactor knowledge preservation

INITIAL DATA RELEASE OF THE KEPLER-INT SURVEY

Energy Technology Data Exchange (ETDEWEB)

Greiss, S.; Steeghs, D.; Gaensicke, B. T. [Department of Physics, Astronomy and Astrophysics group, University of Warwick, CV4 7AL Coventry (United Kingdom); Martin, E. L. [INTA-CSIC Centro de Astrobiologia, Carretera de Ajalvir km 4, 28550 Torrejon de Ardoz (Spain); Groot, P. J.; Verbeek, K.; Jonker, P. G.; Scaringi, S. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Irwin, M. J.; Gonzalez-Solares, E. [Cambridge Astronomy Survey Unit, Institute of Astronomy, University of Cambridge, Madingley Road, CB3 0HA Cambridge (United Kingdom); Greimel, R. [Institut fuer Physik, Karl-Franzen Universitaet Graz, Universitaetsplatz 5, 8010 Graz (Austria); Knigge, C. [School of Physics and Astronomy, University of Southampton, Southampton, Hampshire SO17 1BJ (United Kingdom); Ostensen, R. H. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium); Drew, J. E.; Farnhill, H. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Drake, J.; Wright, N. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ripepi, V. [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, Naples I-80131 (Italy); Southworth, J. [Astrophysics Group, Keele University, Newcastle-under-Lyme ST5 5BG (United Kingdom); Still, M., E-mail: s.greiss@warwick.ac.uk [NASA Ames Research Center, M/S 244-40, Moffett Field, CA 94035 (United States); and others

2012-07-15

This paper describes the first data release of the Kepler-INT Survey (KIS) that covers a 116 deg{sup 2} region of the Cygnus and Lyra constellations. The Kepler field is the target of the most intensive search for transiting planets to date. Despite the fact that the Kepler mission provides superior time-series photometry, with an enormous impact on all areas of stellar variability, its field lacks optical photometry complete to the confusion limit of the Kepler instrument necessary for selecting various classes of targets. For this reason, we follow the observing strategy and data reduction method used in the IPHAS and UVEX galactic plane surveys in order to produce a deep optical survey of the Kepler field. This initial release concerns data taken between 2011 May and August, using the Isaac Newton Telescope on the island of La Palma. Four broadband filters were used, U, g, r, i, as well as one narrowband one, H{alpha}, reaching down to a 10{sigma} limit of {approx}20th mag in the Vega system. Observations covering {approx}50 deg{sup 2}, thus about half of the field, passed our quality control thresholds and constitute this first data release. We derive a global photometric calibration by placing the KIS magnitudes as close as possible to the Kepler Input Catalog (KIC) photometry. The initial data release catalog containing around 6 million sources from all the good photometric fields is available for download from the KIS Web site (www.astro.warwick.ac.uk/research/kis/) as well as via MAST (KIS magnitudes can be retrieved using the MAST enhanced target search page http://archive.stsci.edu/kepler/kepler{sub f}ov/search.php and also via Casjobs at MAST Web site http://mastweb.stsci.edu/kplrcasjobs/).

INITIAL DATA RELEASE OF THE KEPLER-INT SURVEY

International Nuclear Information System (INIS)

Greiss, S.; Steeghs, D.; Gänsicke, B. T.; Martín, E. L.; Groot, P. J.; Verbeek, K.; Jonker, P. G.; Scaringi, S.; Irwin, M. J.; González-Solares, E.; Greimel, R.; Knigge, C.; Østensen, R. H.; Drew, J. E.; Farnhill, H.; Drake, J.; Wright, N. J.; Ripepi, V.; Southworth, J.; Still, M.

2012-01-01

This paper describes the first data release of the Kepler-INT Survey (KIS) that covers a 116 deg 2 region of the Cygnus and Lyra constellations. The Kepler field is the target of the most intensive search for transiting planets to date. Despite the fact that the Kepler mission provides superior time-series photometry, with an enormous impact on all areas of stellar variability, its field lacks optical photometry complete to the confusion limit of the Kepler instrument necessary for selecting various classes of targets. For this reason, we follow the observing strategy and data reduction method used in the IPHAS and UVEX galactic plane surveys in order to produce a deep optical survey of the Kepler field. This initial release concerns data taken between 2011 May and August, using the Isaac Newton Telescope on the island of La Palma. Four broadband filters were used, U, g, r, i, as well as one narrowband one, Hα, reaching down to a 10σ limit of ∼20th mag in the Vega system. Observations covering ∼50 deg 2 , thus about half of the field, passed our quality control thresholds and constitute this first data release. We derive a global photometric calibration by placing the KIS magnitudes as close as possible to the Kepler Input Catalog (KIC) photometry. The initial data release catalog containing around 6 million sources from all the good photometric fields is available for download from the KIS Web site (www.astro.warwick.ac.uk/research/kis/) as well as via MAST (KIS magnitudes can be retrieved using the MAST enhanced target search page http://archive.stsci.edu/kepler/kepler_fov/search.php and also via Casjobs at MAST Web site http://mastweb.stsci.edu/kplrcasjobs/).

Measurements of magnetic field sources in schools

International Nuclear Information System (INIS)

Johnson, G.B.

1992-01-01

The Electrical Systems Division of the Electric Power Research Institute (EPRI) has initiated several research projects to investigate magnetic field levels, their characteristics, and their sources. This paper describes measurements of magnetic field sources in schools. Magnetic field measurements were made at four schools in the service areas of two utility companies. Magnetic field measurements included profiles of the magnetic field versus distance near power lines, around the perimeter of the school buildings, and at several locations within each school. Twenty-four hour measurements were also made to record the temporal variation of the magnetic field at several locations at each school. The instrumentation, measurement techniques, and magnetic field sources identified are discussed

The Saudi Initiative for asthma

Directory of Open Access Journals (Sweden)

Al-Moamary Mohamed

2009-01-01

Full Text Available The Saudi Initiative for Asthma (SINA provides up-to-date guidelines for healthcare workers managing patients with asthma. SINA was developed by a panel of Saudi experts with respectable academic backgrounds and long-standing experience in the field. SINA is founded on the latest available evidence, local literature, and knowledge of the current setting in Saudi Arabia. Emphasis is placed on understanding the epidemiology, pathophysiology, medications, and clinical presentation. SINA elaborates on the development of patient-doctor partnership, self-management, and control of precipitating factors. Approaches to asthma treatment in SINA are based on disease control by the utilization of Asthma Control Test for the initiation and adjustment of asthma treatment. This guideline is established for the treatment of asthma in both children and adults, with special attention to children 5 years and younger. It is expected that the implementation of these guidelines for treating asthma will lead to better asthma control and decrease patient utilization of the health care system.

Electromagnetic fields and cancer

International Nuclear Information System (INIS)

Singh, Neeta; Mathur, R.; Behari, J.

1997-01-01

Several studies in recent years have raised the possibility that exposure to electromagnetic fields (EMFs) may be hazardous to human health, in particular by promotion or initiation of cancer. Recent reports have indicated increased cancer risk from industrial and domestic exposure to environmental ELF fields and to RF fields that are amplitude modulated at ELF. EMF fields have been reported to affect biological systems in various ways, affecting changes in the morphology and or functional behavior of cells, which have been observed in a variety of tissues. Although the mechanism of interaction of EMFs with living cells are not known, it has been proposed that they have multiple effects and can affect cell signalling, including modification of plasma membrane permeability and ion transport. Our findings suggest that EMFs can affect post translational modification of proteins such as poly ADP-ribosylation by epigenetic mechanism and that the effect of EMFs are highly specific regarding both the cell type and the frequency and amplification of the applied field. (author)

The effect of inhomogeneous initial stress on Love wave propagation in layered magneto-electro-elastic structures

International Nuclear Information System (INIS)

Zhang, J; Shen, Y P; Du, J K

2008-01-01

The effect of inhomogeneous initial stress on Love wave propagation in layered magneto-electro-elastic structures is investigated in this paper. The coupled magneto-electro-elastic field equations are solved by adopting the Wentzel–Kramers–Brillouin (WKB) approximate approach. Then the phase velocity can be calculated by applying boundary and continuity conditions. A specific example of a structure consisting of a CoFe 2 O 4 layer and a BaTiO 3 substrate is used to illustrate the influence of inhomogeneous initial stress on the phase velocity, corresponding coupled magneto-electric factor and stress fields. The different influence between constant initial stress and inhomogeneous initial stress is discussed and the results are expected to be helpful for the preparation and application of Love wave sensors

Risk estimation for LCF crack initiation

OpenAIRE

Schmitz, Sebastian; Rollmann, Georg; Gottschalk, Hanno; Krause, Rolf

2013-01-01

An accurate risk assessment for fatigue damage is of vital importance for the design and service of today's turbomachinery components. We present an approach for quantifying the probability of crack initiation due to surface driven low-cycle fatigue (LCF). This approach is based on the theory of failure-time processes and takes inhomogeneous stress fields and size effects into account. The method has been implemented as a finite-element postprocessor which uses quadrature formulae of higher o...

Multiple fields in stochastic inflation

Energy Technology Data Exchange (ETDEWEB)

Assadullahi, Hooshyar [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Firouzjahi, Hassan [School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Noorbala, Mahdiyar [Department of Physics, University of Tehran,P.O. Box 14395-547, Tehran (Iran, Islamic Republic of); School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Vennin, Vincent; Wands, David [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)

2016-06-24

Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary e-folds. Solving the resulting partial differential equations in multi-dimensional field space is more challenging than the single-field case. A few tractable examples are discussed, which show that the number of fields is, in general, a critical parameter. When more than two fields are present for instance, the probability to explore arbitrarily large-field regions of the potential, otherwise inaccessible to single-field dynamics, becomes non-zero. In some configurations, this gives rise to an infinite mean number of e-folds, regardless of the initial conditions. Another difference with respect to single-field scenarios is that multi-field stochastic effects can be large even at sub-Planckian energy. This opens interesting new possibilities for probing quantum effects in inflationary dynamics, since the moments of the numbers of e-folds can be used to calculate the distribution of primordial density perturbations in the stochastic-δN formalism.

Scalar-field amplitudes in black-hole evaporation

International Nuclear Information System (INIS)

Farley, A.N.St.J.; D'Eath, P.D.

2004-01-01

We consider the quantum-mechanical decay of a Schwarzschild-like black hole into almost-flat space and weak radiation at a very late time. That is, we are concerned with evaluating quantum amplitudes (not just probabilities) for transitions from initial to final states. In this quantum description, no information is lost because of the black hole. The Lagrangian is taken, in the first instance, to consist of the simplest locally supersymmetric generalization of Einstein gravity and a massless scalar field. The quantum amplitude to go from given initial to final bosonic data in a slightly complexified time-interval T=τexp(-iθ) at infinity may be approximated by the form constxexp(-I), where I is the (complex) Euclidean action of the classical solution filling in between the boundary data. Additionally, in a pure supergravity theory, the amplitude constxexp(-I) is exact. Suppose that Dirichlet boundary data for gravity and the scalar field are posed on an initial spacelike hypersurface extending to spatial infinity, just prior to collapse, and on a corresponding final spacelike surface, sufficiently far to the future of the initial surface to catch all the Hawking radiation. Only in an averaged sense will this radiation have an approximately spherically-symmetric distribution. If the time-interval T had been taken to be exactly real, then the resulting 'hyperbolic Dirichlet boundary-value problem' would, as is well known, not be well posed. Provided instead ('Euclidean strategy') that one takes T complex, as above (0<θ=<π/2), one expects that the field equations become strongly elliptic, and that there exists a unique solution to the classical boundary-value problem. Within this context, by expanding the bosonic part of the action to quadratic order in perturbations about the classical solution, one obtains the quantum amplitude for weak-field final configurations, up to normalization. Such amplitudes are here calculated for weak final scalar fields

High-field magnetization of dilute rare earths in yttrium

DEFF Research Database (Denmark)

Touborg, P.; Høg, J.; Cock, G. J.

1974-01-01

Magnetization measurements have been performed on single crystals of Y containing small amounts of Tb, Dy, or Er at 4.2 K in fields up to 295 × 105 A/m (370 kOe). Crystal-field and molecular-field parameters obtained from measurements of the initial susceptibility versus temperature give a satisf...... a satisfactory quantitative account of the high-field magnetization. This includes characteristic features due to the crossing and mixing of crystal-field levels....

Charged particles scattering in the presence of an homogeneous magnetic field

International Nuclear Information System (INIS)

Brandi, J.S.; Koiller, B.; Barros, H.G.P.L. de; Miranda, L.C.M.

1977-01-01

The scattering of charged particles in the presence of an homogeneous magnetic field, is studied. Using the Green's function formalism, an appropriate transition amplitude for the scattering process is defined, and an application is done for the scattering by a Coulomb potential in the high energy approximation. For this case, the transition amplitude is obtained in a closed form; its behavior with the magnetic field intensity and initial translational energy is qualitatively discussed. In the ultra-strong field limit, the total transition probability presents periodic resonances with increasing values of the initial translational energy [pt

Dynamics of atom-field entanglement for Tavis-Cummings models

Science.gov (United States)

Bashkirov, Eugene K.

2018-04-01

An exact solution of the problem of two-atom one- and two-mode Jaynes-Cummings model with intensity- dependent coupling is presented. Asymptotic solutions for system state vectors are obtained in the approximation of large initial coherent fields. The atom-field entanglement is investigated on the basis of the reduced atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process for both models is shown. Conditions and times of disentanglement are derived.

Phase Structure of Strong-Field Tunneling Wave Packets from Molecules.

Science.gov (United States)

Liu, Ming-Ming; Li, Min; Wu, Chengyin; Gong, Qihuang; Staudte, André; Liu, Yunquan

2016-04-22

We study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo model to describe the laser-driven dynamics of photoelectron momentum distributions of molecules. Using our model, we reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N_{2} reported by M. Meckel et al. [Nat. Phys. 10, 594 (2014)]. In addition to modeling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both the initial transverse momentum distribution and the molecular internuclear distance. We further show that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. The phase structure of the photoelectron wave packet is a key ingredient for modeling strong-field molecular photoelectron holography, high-harmonic generation, and molecular orbital imaging.

Vortex rings and jets recent developments in near-field dynamics

CERN Document Server

Yu, Simon

2015-01-01

In this book, recent developments in our understanding of fundamental vortex ring and jet dynamics will be discussed, with a view to shed light upon their near-field behaviour which underpins much of their far-field characteristics. The chapters provide up-to-date research findings by their respective experts and seek to link near-field flow physics of vortex ring and jet flows with end-applications in mind. Over the past decade, our knowledge on vortex ring and jet flows has grown by leaps and bounds, thanks to increasing use of high-fidelity, high-accuracy experimental techniques and numerical simulations. As such, we now have a much better appreciation and understanding on the initiation and near-field developments of vortex ring and jet flows under many varied initial and boundary conditions. Chapter 1 outlines the vortex ring pinch-off phenomenon and how it relates to the initial stages of jet formations and subsequent jet behaviour, while Chapter 2 takes a closer look at the behaviour resulting from vor...

Magnetomigration of rare-earth ions in inhomogeneous magnetic fields.

Science.gov (United States)

Franczak, Agnieszka; Binnemans, Koen; Jan Fransaer

2016-10-05

The effects of external inhomogenous (gradient) magnetic fields on the movement of the rare-earth ions: Dy 3+ , Gd 3+ and Y 3+ , in initially homogeneous aqueous solutions have been investigated. Differences in the migration of rare-earth ions in gradient magnetic fields were observed, depending on the magnetic character of the ions: paramagnetic ions of Dy 3+ and Gd 3+ move towards regions of the sample where the magnetic field gradient is the strongest, while diamagnetic ions of Y 3+ move in the opposite direction. It has been showed that the low magnetic field gradients, such the ones generated by permanent magnets, are sufficient to observe the magnetomigration effects of the ions in solution. The present work clearly establishes the behavior of magnetically different ions in initially homogeneous aqueous solutions exposed to magnetic field gradients. To this avail, a methodology for measuring the local concentration differences of metal ions in liquid samples was developed.

Clinical indications for high-field 1.5 T intraoperative magnetic resonance imaging and neuro-navigation for neurosurgical procedures. Review of initial 100 cases

International Nuclear Information System (INIS)

Maesawa, Satoshi; Nakahara, Norimoto; Watanabe, Tadashi; Fujii, Masazumi; Saito, Kiyoshi; Kajita, Yasukazu; Nagatani, Tetsuya; Wakabayashi, Toshihiko; Yoshida, Jun

2009-01-01

Initial experiences are reviewed in an integrated operation theater equipped with an intraoperative high-field (1.5 T) magnetic resonance (MR) imager and neuro-navigation (BrainSUITE), to evaluate the indications and limitations. One hundred consecutive cases were treated, consisting of 38 gliomas, 49 other tumors, 11 cerebrovascular diseases, and 2 functional diseases. The feasibility and usefulness of the integrated theater were evaluated for individual diseases, focusing on whether intraoperative images (including diffusion tensor imaging) affected the surgical strategy. The extent of resection and outcomes in each histological category of brain tumors were examined. Intraoperative high-field MR imaging frequently affected or modified the surgical strategy in the glioma group (27/38 cases, 71.1%), but less in the other tumor group (13/49 cases, 26.5%). The surgical strategy was not modified in cerebrovascular or functional diseases, but the success of procedures and the absence of complications could be confirmed. In glioma surgery, subtotal or greater resection was achieved in 22 of the 31 patients (71%) excluding biopsies, and intraoperative images revealed tumor remnants resulting in the extension of resection in 21 of the 22 patients (95.4%), the highest rate of extension among all types of pathologies. The integrated neuro-navigation improved workflow. The best indication for intraoperative high-field MR imaging and integrated neuro-navigation is brain tumors, especially gliomas, and is supplementary in assuring quality in surgery for cerebrovascular or functional diseases. Immediate quality assurance is provided in several types of neurosurgical procedures. (author)

Dynamics of floret initiation/death determining spike fertility in wheat as affected by Ppd genes under field conditions.

Science.gov (United States)

Prieto, Paula; Ochagavía, Helga; Savin, Roxana; Griffiths, Simon; Slafer, Gustavo A

2018-04-27

As wheat yield is linearly related to grain number, understanding the physiological determinants of the number of fertile florets based on floret development dynamics due to the role of the particular genes is relevant. The effects of photoperiod genes on dynamics of floret development are largely ignored. Field experiments were carried out to (i) characterize the dynamics of floret primordia initiation and degeneration and (ii) to determine which are the most critical traits of such dynamics in establishing genotypic differences in the number of fertile florets at anthesis in near isogenic lines (NILs) carrying photoperiod-insensitive alleles. Results varied in magnitude between the two growing seasons, but in general introgression of Ppd-1a alleles reduced the number of fertile florets. The actual effect was affected not only by the genome and the doses but also by the source of the alleles. Differences in the number of fertile florets were mainly explained by differences in the floret generation/degeneration dynamics, and in most cases associated with floret survival. Manipulating photoperiod insensitivity, unquestionably useful for changing flowering time, may reduce spike fertility but much less than proportionally to the change in duration of development, as the insensitivity alleles did increase the rate of floret development.

Computer analysis of multicircuit shells of revolution by the field method

International Nuclear Information System (INIS)

Cohen, G.A.

1975-01-01

The method of analysis developed which has been termed the 'field method' converts the boundary-value problem into two successive initial-value problems. In the first initial-value problem, a forward integration over the shell meridian is made for the 'field functions', which may be interpreted physically as influence functions (plus additional functions to account for external loading) of the structure. The second initial-value problem consists of a backward integration (i.e., in the reverse direction) for the physical force and displacement functions, the differential equations for which are dependent on the already calculated field functions. In this method, no artificial subdivision of the meridian is necessary since both initial-value problems are numerically stable. Also, because the physical response functions are obtained directly from the backward integration, their storage points may be chosen automatically during execution to obtain a uniformly 'dense' description of these functions. Studies comparing the efficiency (i.e., execution time) of the field method with that of a conventional superposition (Zarghamee) method have been made, for the simple case of the linear static response of a clamped cylindrical shell. The field method has been presented previously for shells of revolution with open branched meridians. This work is now extended to the case of meridians which contain circuits. Also, a new method for the treatment of arbitrary kinematic constraints is presented

Manifestation of interplanetary medium parameters in development of a geomagnetic storm initial phase

International Nuclear Information System (INIS)

Chkhetiya, A.M.

1988-01-01

The role of solar wind plasma parameters in formation of a geomagnetic storm initial phase is refined. On the basis of statistical analysis an empirical formula relating the interplanetary medium parameters (components of interplanetary magnetic field, proton velocity and concentration) and D st -index during the geomagnetic storm initial phase is proposed

Invited Article: First flight in space of a wide-field-of-view soft x-ray imager using lobster-eye optics: Instrument description and initial flight results.

Science.gov (United States)

Collier, Michael R; Porter, F Scott; Sibeck, David G; Carter, Jenny A; Chiao, Meng P; Chornay, Dennis J; Cravens, Thomas E; Galeazzi, Massimiliano; Keller, John W; Koutroumpa, Dimitra; Kujawski, Joseph; Kuntz, Kip; Read, Andy M; Robertson, Ina P; Sembay, Steve; Snowden, Steven L; Thomas, Nicholas; Uprety, Youaraj; Walsh, Brian M

2015-07-01

We describe the development, launch into space, and initial results from a prototype wide field-of-view soft X-ray imager that employs lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The sheath transport observer for the redistribution of mass is the first instrument using this type of optics launched into space and provides proof-of-concept for future flight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the Moon, and the solar wind interaction with planetary bodies like Venus and Mars [Kuntz et al., Astrophys. J. (in press)].

Rapid change of field line connectivity and reconnection in stochastic magnetic fields

International Nuclear Information System (INIS)

Huang, Yi-Min; Bhattacharjee, A.; Boozer, Allen H.

2014-01-01

Magnetic fields without a direction of continuous symmetry have the generic feature that neighboring field lines exponentiate away from each other and become stochastic, and hence the ideal constraint of preserving magnetic field line connectivity becomes exponentially sensitive to small deviations from ideal Ohm's law. The idea of breaking field line connectivity by stochasticity as a mechanism for fast reconnection is tested with numerical simulations based on reduced magnetohydrodynamics equations with a strong guide field line-tied to two perfectly conducting end plates. Starting from an ideally stable force-free equilibrium, the system is allowed to undergo resistive relaxation. Two distinct phases are found in the process of resistive relaxation. During the quasi-static phase, rapid change of field line connectivity and strong induced flow are found in regions of high field line exponentiation. However, although the field line connectivity of individual field lines can change rapidly, the overall pattern of field line mapping appears to deform gradually. From this perspective, field line exponentiation appears to cause enhanced diffusion rather than reconnection. In some cases, resistive quasi-static evolution can cause the ideally stable initial equilibrium to cross a stability threshold, leading to formation of intense current filaments and rapid change of field line mapping into a qualitatively different pattern. It is in this onset phase that the change of field line connectivity is more appropriately designated as magnetic reconnection. Our results show that rapid change of field line connectivity appears to be a necessary, but not a sufficient condition for fast reconnection.

340 and 310 drawing field verification

International Nuclear Information System (INIS)

Langdon, J.

1996-01-01

The purpose of the drawing field verification work plan is to provide reliable drawings for the 310 Treated Effluent Disposal Facility (TEDF) and 340 Waste Handling Facility (340 Facility). The initial scope of this work plan is to provide field verified and updated versions of all the 340 Facility essential drawings. This plan can also be used for field verification of any other drawings that the facility management directs to be so updated. Any drawings revised by this work plan will be issued in an AutoCAD format

Initial Pressure Distribution in the Geothermal Field of Los Humeros, Puebla, Mexico; Distribucion de presion inicial en el campo geotermico de Los Humeros, Puebla, Mexico

Energy Technology Data Exchange (ETDEWEB)

Arellano, Victor M.; Izquierdo, Georgina; Aragon, Alfonso; Barragan, Rosa Maria; Garcia, Alfonso [Instituto de Investigaciones Electricas (Mexico); Pizano, Arturo [Comision Federal de Electricidad (Mexico)

2001-09-01

To obtain the undisturbed distribution of pressures of a field flow, a significant amount of data concerning geological, geochemical, geophysical, and field drilling and engineering aspects, from 42 wells located at the geothermal field of Los Humeros, was analysed. Based on the studied data, models of the field pressure distribution in its initial state were developed. The models reveal the existence of at least two deposits. One of them, the most superficial, is located between 1025 and 1600 meters over the sea level, and from its excellent congruence with the pressure profile of a boiling water column, it may be considered as a predominantly liquid field. The pressure profile of this field is that of a boiling water column, at a temperature of about 300-330 Celsius degrees. The second field is below 850 meters over the sea level and from the known data it reaches at least 100 meters over the sea level. It is considered a low-liquid saturated field. The temperatures of the wells supplied by this field were estimated to be about 300-40 Celsius degrees. [Spanish] Para inferir las distribuciones de presion no perturbadas del fluido del yacimiento, se analizo una considerable cantidad de informacion relacionada con los aspectos geologicos, geoquimicos, geofisicos, de perforacion e ingenieria de yacimientos, correspondiente a 42 pozos del camo geotermico de Los Humeros, Puebla. Sobre la base de los datos analizados se desarrollaron modelos de distribucion de la presion del yacimiento en su estado inicial. Dichos modelos revelan la existencia de, cuando menos, dos yacimientos. El primero y mas superficial se encuentra localizado entre 1,600 y 1,025 metros sobre el nivel del mar (msnm), y dada su excelente concordancia con el perfil de presion correspondiente a una columna de agua en ebullicion, puede afirmarse que se trata de un yacimiento de liquido dominante. El perfil de presion de este yacimiento corresponde a una columna de agua en ebullicion de 300 a 330

Initiative de renforcement du leadership en recherche en écosanté ...

International Development Research Centre (IDRC) Digital Library (Canada)

Institution. Kunming Institute of Botany, Chinese Academy of Sciences as represented by Sun Hang ... Ecohealth research in Southeast Asia : past, present and the way forward ... Ecohealth Field-building Leadership Initiative in Southeast Asia.

Environmental biotechnologies for the fossil fuel industry

Energy Technology Data Exchange (ETDEWEB)

Lee, D W; Donald, G M [Hycal Energy Research Labs. Ltd., Calgary, AB (Canada)

1997-09-01

Five recent technologies that have been proven to be viable means to mitigate the environmental impact of the fossil fuel industry were described as evidence of the industry`s concern about environmental pollution. The technologies were: bioventing, bioslurping, biofiltration, phytoremediation and the use of genetically engineered organisms. Special attention was paid to genetic modification strategies with reference to improved degradation rates and the regulations in Canada affecting genetically engineered organisms and their use. Case histories were cited to illustrate application of the various processes. 34 refs.

Environmental biotechnologies for the fossil fuel industry

International Nuclear Information System (INIS)

Lee, D. W.; Donald, G. M.

1997-01-01

Five recent technologies that have been proven to be viable means to mitigate the environmental impact of the fossil fuel industry were described as evidence of the industry's concern about environmental pollution. The technologies were: bioventing, bioslurping, biofiltration, phytoremediation and the use of genetically engineered organisms. Special attention was paid to genetic modification strategies with reference to improved degradation rates and the regulations in Canada affecting genetically engineered organisms and their use. Case histories were cited to illustrate application of the various processes. 34 refs

Weaving Knotted Vector Fields with Tunable Helicity.

Science.gov (United States)

Kedia, Hridesh; Foster, David; Dennis, Mark R; Irvine, William T M

2016-12-30

We present a general construction of divergence-free knotted vector fields from complex scalar fields, whose closed field lines encode many kinds of knots and links, including torus knots, their cables, the figure-8 knot, and its generalizations. As finite-energy physical fields, they represent initial states for fields such as the magnetic field in a plasma, or the vorticity field in a fluid. We give a systematic procedure for calculating the vector potential, starting from complex scalar functions with knotted zero filaments, thus enabling an explicit computation of the helicity of these knotted fields. The construction can be used to generate isolated knotted flux tubes, filled by knots encoded in the lines of the vector field. Lastly, we give examples of manifestly knotted vector fields with vanishing helicity. Our results provide building blocks for analytical models and simulations alike.

Teachers’ perceptions of their own initiative: Collective initiative vs. personal initiative

Directory of Open Access Journals (Sweden)

Džinović Vladimir

2013-01-01

Full Text Available Current trends in education demand from teachers to exhibit proactive behaviour and assume responsibility for the implementation of changes in school practice. In that sense, it is important to study how teachers perceive their own initiative and to gain insight into the activities where such initiative is demonstrated. This study has been conceived as a mixed-methods research. The qualitative study implied forming four focus groups with subject teachers and class teachers (N=38, while the quantitative study entailed surveying 1441 teachers in forty primary schools in Serbia using the questionnaire constructed based on qualitative data. Data from focus groups were processed by qualitative thematic analysis, while the questionnaire data were processed by principal component analysis and univariate analysis of variance. The findings of the study have shown that teachers mostly demonstrate initiative through co­operative activities that include planning of joint teaching as well as conducting joint projects within school and with the local community actors. Teachers are least ready to demonstrate personal initiative and the initiative aimed at accomplishing considerable changes in school work. The concluding part includes the recommendations for encouraging teachers’ personal initiative and building organizational culture that would support such initiative. [Projekat Ministarstva nauke Republike Srbije, br. br. 47008: Unapređivanje kvaliteta i dostupnosti obrazovanja u procesima modernizacije Srbije i br. 179034: Od podsticanja inicijative, saradnje i stvaralaštva u obrazovanju do novih uloga i identiteta u društvu

NASA Gulf of Mexico Initiative Hypoxia Research

Science.gov (United States)

Armstrong, Curtis D.

2012-01-01

The Applied Science & Technology Project Office at Stennis Space Center (SSC) manages NASA's Gulf of Mexico Initiative (GOMI). Addressing short-term crises and long-term issues, GOMI participants seek to understand the environment using remote sensing, in-situ observations, laboratory analyses, field observations and computational models. New capabilities are transferred to end-users to help them make informed decisions. Some GOMI activities of interest to the hypoxia research community are highlighted.

Construction of a field trap for initiating an ovipositional response in Aedes taeniorhynchus.

Science.gov (United States)

Wallace, F L

1996-09-01

An oviposition trap was constructed for the black saltmarsh mosquito, Aedes taeniorhynchus. The trap consisted of a 50 x 60-cm piece of contaminated 100% cotton bath towel, saturated with 85% tap water, a container, and a cover of dried plant parts placed over the contaminated toweling. This combination initiated oviposition. Contamination of the toweling was due to populations of bacteria and fungi. The eggs recovered were free from soil and debris.

Teachers' Personal Learning Networks (PLNs): Exploring the Nature of Self-Initiated Professional Learning Online

Science.gov (United States)

Tour, Ekaterina

2017-01-01

In the field of Literacy Studies, online spaces have been recognised as providing many opportunities for spontaneous and self-initiated learning. While some progress has been made in understanding these important learning experiences, little attention has been paid to teachers' self-initiated professional learning. Contributing to the debates…

Southern African Regional Science Initiative (SAFARI 2000): wet season campaigns

CSIR Research Space (South Africa)

Otter, LB

2002-03-01

Full Text Available The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia...

[The subject repositories of strategy of the Open Access initiative].

Science.gov (United States)

Soares Guimarães, M C; da Silva, C H; Horsth Noronha, I

2012-11-01

The subject repositories are defined as a set of digital objects resulting from the research related to a specific disciplinary field and occupy a still restricted space in the discussion agenda of the Free Access Movement when compared to amplitude reached in the discussion of Institutional Repositories. Although the Subject Repository comes to prominence in the field, especially for the success of initiatives such as the arXiv, PubMed and E-prints, the literature on the subject is recognized as very limited. Despite its roots in the Library and Information Science, and focus on the management of disciplinary collections (subject area literature), there is little information available about the development and management of subject repositories. The following text seeks to make a brief summary on the topic as a way to present the potential to develop subject repositories in order to strengthen the initiative of open access.

Initiation of vacuum breakdown and failure mechanism of the carbon nanotube during thermal field emission

Science.gov (United States)

Dan, Cai; Lie, Liu; Jin-Chuan, Ju; Xue-Long, Zhao; Hong-Yu, Zhou; Xiao, Wang

2016-04-01

The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method. Project supported by the National Natural Science Foundation of China (Grant Nos. 11305263 and 61401484).

Internal magnetic field measurements in a translating field-reversed configuration

International Nuclear Information System (INIS)

Armstrong, W.T.; Chrien, R.E.; McKenna, K.F.; Rej, D.J.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

1984-01-01

Magnetic field probes have been employed to study the internal field structure of Field-Reversed Configurations (FRCs) translating past the probes in the FRX-C/T device. Internal closed flux surfaces can be studied in this manner with minimal perturbation because of the rapid transit of the plasma (translational velocity v/sub z/ approx. 10 cm/μs). Data have been taken using a low-field (5 kG), 5-mtorr-D 2 gas-puff mode of operation in the FRC source coil which yields an initial plasma density of approx. 1 x 10 15 cm -3 and x/sub s/ approx. 0.04. FRCs translate from the approx. 25 cm radius source coil into a 20 cm radius metal translation vessel. Two translation conditions are studied: (1) translation into a 4 kG guide field (matched guide-field case), resulting in similar plasma parameters but with x/sub s/ approx. .45, and (2) translation into a 1 kG guide field (reduced guide-field case), resulting in expansion of the FRC to conditions of density approx. 3 x 10 14 , external field B 0 approx. 2 kG and x/sub s/ approx. 0.7. The expected reversed B/sub z/ structure is observed in both cases. However, the field measurements indicate a possible sideways offset of the FRC from the machine axis in the matched case. There is also evidence of island structure in the reduced guide-field case. Fluctuating levels of B/sub theta/ are ovserved with amplitudes less than or equal to B 0 /3 in both cases. Field measurements on the FRC symmetry axis in the reduced guide-field case indicate β on the separatrix of β/sub s/ approx. = 0.3 (indexed to the external field) has been achieved. This decrease of β/sub s/ with increased x/sub s/ is expected, and desirable for improved plasma confinement

Killing fields; The epidemiological evidence

Energy Technology Data Exchange (ETDEWEB)

Best, Simon

1990-02-01

The threat posed by low frequency fields emerged initially because a researcher, looking for environmental factors in childhood leukaemia, observed a link between low voltage, high current power lines and disease occurrence. Cellular evidence now supports the findings but epidemiology still leads the argument. (43 references). (author).

SU-F-T-261: Reconstruction of Initial Photon Fluence Based On EPID Images

Energy Technology Data Exchange (ETDEWEB)

Seliger, T; Engenhart-Cabillic, R [Philipp University of Marburg, Marburg (Germany); Czarnecki, D; Maeder, U; Zink, K [Technische Hochschule Mittelhessen - University of Applied Sciences, Giessen (Germany); Kussaether, R [MedCom GmbH, Darmstadt (Germany); Poppe, B [University Hospital for Medical Radiation Physics, Pius-Hospital, Medical Campus, Carl von Ossietzky University of Oldenburg (Germany)

2016-06-15

Purpose: Verifying an algorithm to reconstruct relative initial photon fluence for clinical use. Clinical EPID and CT images were acquired to reconstruct an external photon radiation treatment field. The reconstructed initial photon fluence could be used to verify the treatment or calculate the applied dose to the patient. Methods: The acquired EPID images were corrected for scatter caused by the patient and the EPID with an iterative reconstruction algorithm. The transmitted photon fluence behind the patient was calculated subsequently. Based on the transmitted fluence the initial photon fluence was calculated using a back-projection algorithm which takes the patient geometry and its energy dependent linear attenuation into account. This attenuation was gained from the acquired cone-beam CT or the planning CT by calculating a water-equivalent radiological thickness for each irradiation direction. To verify the algorithm an inhomogeneous phantom consisting of three inhomogeneities was irradiated by a static 6 MV photon field and compared to a reference flood field image. Results: The mean deviation between the reconstructed relative photon fluence for the inhomogeneous phantom and the flood field EPID image was 3% rising up to 7% for off-axis fluence. This was probably caused by the used clinical EPID calibration, which flattens the inhomogeneous fluence profile of the beam. Conclusion: In this clinical experiment the algorithm achieved good results in the center of the field while it showed high deviation of the lateral fluence. This could be reduced by optimizing the EPID calibration, considering the off-axis differential energy response. In further progress this and other aspects of the EPID, eg. field size dependency, CT and dose calibration have to be studied to realize a clinical acceptable accuracy of 2%.

Initial pen and field assessment of baits to use in oral rabies vaccination of Formosan ferret-badgers in response to the re-emergence of rabies in Taiwan.

Science.gov (United States)

Wallace, Ryan M; Lai, Yuching; Doty, Jeffrey B; Chen, Chen-Chih; Vora, Neil M; Blanton, Jesse D; Chang, Susan S; Cleaton, Julie M; Pei, Kurtis J C

2018-01-01

Taiwan had been considered rabies free since 1961, until a newly established wildlife disease surveillance program identified rabies virus transmission within the Formosan ferret-badger (Melogale moschata subaurantiaca) in 2013. Ferret-badgers occur throughout southern China and Southeast Asia, but their ecological niche is not well described. As an initial feasibility assessment for potential rabies control measures, field camera trapping and pen assessment of 6 oral rabies vaccine (ORV) baits were conducted in Taiwan in 2013. 46 camera nights were recorded; 6 Formosan ferret-badgers and 14 non-target mammals were sighted. No baits were consumed by ferret-badgers and 8 were consumed by non-target mammals. Penned ferret-badgers ingested 5 of the 18 offered baits. When pen and field trials were combined, and analyzed for palatability, ferret-badgers consumed 1 of 9 marshmallow baits (11.1%), 1 of 21 fishmeal baits (4.8%), 0 of 3 liver baits, and 3 of 3 fruit-flavored baits. It took an average of 261 minutes before ferret-badgers made oral contact with the non-fruit flavored baits, and 34 minutes for first contact with the fruit-based bait. Overall, ferret-badgers sought out the fruit baits 8 times faster, spent a greater proportion of time eating fruit baits, and were 7.5 times more likely to have ruptured the vaccine container of the fruit-based bait. Ferret-badgers are now recognized as rabies reservoir species in China and Taiwan, through two independent 'dog to ferret-badger' host-shift events. Species of ferret-badgers can be found throughout Indochina, where they may be an unrecognized rabies reservoir. Findings from this initial study underscore the need for further captive and field investigations of fruit-based attractants or baits developed for small meso-carnivores. Non-target mammals' competition for baits, ants, bait design, and dense tropical landscape represent potential challenges to effective ORV programs that will need to be considered in future

Initial pen and field assessment of baits to use in oral rabies vaccination of Formosan ferret-badgers in response to the re-emergence of rabies in Taiwan.

Directory of Open Access Journals (Sweden)

Ryan M Wallace

Full Text Available Taiwan had been considered rabies free since 1961, until a newly established wildlife disease surveillance program identified rabies virus transmission within the Formosan ferret-badger (Melogale moschata subaurantiaca in 2013. Ferret-badgers occur throughout southern China and Southeast Asia, but their ecological niche is not well described.As an initial feasibility assessment for potential rabies control measures, field camera trapping and pen assessment of 6 oral rabies vaccine (ORV baits were conducted in Taiwan in 2013. 46 camera nights were recorded; 6 Formosan ferret-badgers and 14 non-target mammals were sighted. No baits were consumed by ferret-badgers and 8 were consumed by non-target mammals. Penned ferret-badgers ingested 5 of the 18 offered baits. When pen and field trials were combined, and analyzed for palatability, ferret-badgers consumed 1 of 9 marshmallow baits (11.1%, 1 of 21 fishmeal baits (4.8%, 0 of 3 liver baits, and 3 of 3 fruit-flavored baits. It took an average of 261 minutes before ferret-badgers made oral contact with the non-fruit flavored baits, and 34 minutes for first contact with the fruit-based bait. Overall, ferret-badgers sought out the fruit baits 8 times faster, spent a greater proportion of time eating fruit baits, and were 7.5 times more likely to have ruptured the vaccine container of the fruit-based bait.Ferret-badgers are now recognized as rabies reservoir species in China and Taiwan, through two independent 'dog to ferret-badger' host-shift events. Species of ferret-badgers can be found throughout Indochina, where they may be an unrecognized rabies reservoir. Findings from this initial study underscore the need for further captive and field investigations of fruit-based attractants or baits developed for small meso-carnivores. Non-target mammals' competition for baits, ants, bait design, and dense tropical landscape represent potential challenges to effective ORV programs that will need to be

Initial pen and field assessment of baits to use in oral rabies vaccination of Formosan ferret-badgers in response to the re-emergence of rabies in Taiwan

Science.gov (United States)

Wallace, Ryan M.; Lai, Yuching; Doty, Jeffrey B.; Chen, Chen-Chih; Vora, Neil M.; Blanton, Jesse D.; Chang, Susan S.; Pei, Kurtis J. C.

2018-01-01

Background Taiwan had been considered rabies free since 1961, until a newly established wildlife disease surveillance program identified rabies virus transmission within the Formosan ferret-badger (Melogale moschata subaurantiaca) in 2013. Ferret-badgers occur throughout southern China and Southeast Asia, but their ecological niche is not well described. Methodology/Principle findings As an initial feasibility assessment for potential rabies control measures, field camera trapping and pen assessment of 6 oral rabies vaccine (ORV) baits were conducted in Taiwan in 2013. 46 camera nights were recorded; 6 Formosan ferret-badgers and 14 non-target mammals were sighted. No baits were consumed by ferret-badgers and 8 were consumed by non-target mammals. Penned ferret-badgers ingested 5 of the 18 offered baits. When pen and field trials were combined, and analyzed for palatability, ferret-badgers consumed 1 of 9 marshmallow baits (11.1%), 1 of 21 fishmeal baits (4.8%), 0 of 3 liver baits, and 3 of 3 fruit-flavored baits. It took an average of 261 minutes before ferret-badgers made oral contact with the non-fruit flavored baits, and 34 minutes for first contact with the fruit-based bait. Overall, ferret-badgers sought out the fruit baits 8 times faster, spent a greater proportion of time eating fruit baits, and were 7.5 times more likely to have ruptured the vaccine container of the fruit-based bait. Conclusions/Significance Ferret-badgers are now recognized as rabies reservoir species in China and Taiwan, through two independent ‘dog to ferret-badger’ host-shift events. Species of ferret-badgers can be found throughout Indochina, where they may be an unrecognized rabies reservoir. Findings from this initial study underscore the need for further captive and field investigations of fruit-based attractants or baits developed for small meso-carnivores. Non-target mammals’ competition for baits, ants, bait design, and dense tropical landscape represent potential

Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

Energy Technology Data Exchange (ETDEWEB)

Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

1992-01-01

Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site's microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog [reg sign] evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog[reg sign] activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

Energy Technology Data Exchange (ETDEWEB)

Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

1992-12-31

Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site`s microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog {reg_sign} evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog{reg_sign} activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

Conformal changes of metrics and the initial-value problem of general relativity

International Nuclear Information System (INIS)

Mielke, E.W.

1977-01-01

Conformal techniques are reviewed with respect to applications to the initial-value problem of general relativity. Invariant transverse traceless decompositions of tensors, one of its main tools, are related to representations of the group of 'conformeomorphisms' acting on the space of all Riemannian metrics on M. Conformal vector fields, a kernel in the decomposition, are analyzed on compact manifolds with constant scalar curvature. The realization of arbitrary functions as scalar curvature of conformally equivalent metrics, a generalization of Yamabe's (Osaka Math. J.; 12:12 (1960)) conjecture, is applied to the Hamiltonian constraint and to the issue of positive energy of gravitational fields. Various approaches to the solution of the initial-value equations produced by altering the scaling behaviour of the second fundamental form are compared. (author)

Frontier Fields: Bringing the Distant Universe into View

Science.gov (United States)

Eisenhamer, Bonnie; Lawton, Brandon L.; Summers, Frank; Ryer, Holly

2014-06-01

The Frontier Fields is a multi-cycle program of six deep-field observations of strong-lensing galaxy clusters that will be taken in parallel with six deep “blank fields.” The three-year long collaborative program centers on observations from NASA’s Great Observatories, who will team up to look deeper into the universe than ever before, and potentially uncover galaxies that are as much as 100 times fainter than what the telescopes can typically see. Because of the unprecedented views of the universe that will be achieved, the Frontier Fields science program is ideal for informing audiences about scientific advances and topics in STEM. For example, the program provides an opportunity to look back on the history of deep field observations and how they changed (and continue to change) astronomy, while exploring the ways astronomers approach big science problems. As a result, the Space Telescope Science Institute’s Office of Public Outreach has initiated an education and public outreach (E/PO) project to follow the progress of the Frontier Fields program - providing a behind-the-scenes perspective of this observing initiative. This poster will highlight the goals of the Frontier Fields E/PO project and the cost-effective approach being used to bring the program’s results to both the public and educational audiences.

Stress and strain field singularities, micro-cracks, and their role in failure initiation at the composite laminate free-edge

Science.gov (United States)

Dustin, Joshua S.

A state-of-the-art multi-scale analysis was performed to predict failure initiation at the free-edge of an angle-ply laminate using the Strain Invariant Failure Theory (SIFT), and multiple improvements to this analysis methodology were proposed and implemented. Application of this analysis and theory led to the conclusion that point-wise failure criteria which ignore the singular stress and strain fields from a homogenized analysis and the presence of free-edge damage in the form of micro-cracking, may do so at the expense of failure prediction capability. The main contributions of this work then are made in the study of the laminate free-edge singularity and in the effects of micro-cracking at the composite laminate free-edge. Study of both classical elasticity and finite element solutions of the laminate free-edge stress field based upon the assumption of homogenized lamina properties reveal that the order of the free-edge singularity is sufficiently small such that the domain of dominance of this term away from the laminate free-edge is much smaller than the relevant dimensions of the microstructure. In comparison to a crack-tip field, these free-edge singularities generate stress and strain fields which are half as intense as those at the crack-tip, leading to the conclusion that existing flaws at the free-edge in the form of micro-cracks would be more prone to the initiation of free-edge failure than the existence of a singularity in the free-edge elasticity solutions. A methodical experiment was performed on a family of [±25°/90°] s laminates made of IM7/8552 carbon/epoxy composite, to both characterize micro-cracks present at the laminate free-edge and to study their behavior under the application of a uniform extensional load. The majority of these micro-cracks were of length on the order of a few fiber diameters, though larger micro-cracks as long as 100 fiber diameters were observed in thicker laminates. A strong correlation between the application of

Threats to ultra-high-field MRI

Science.gov (United States)

Le Bihan, Denis

2009-08-01

In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are necessary to prevent workers from suffering any undue acute health effects. But although not initially intended, the biggest impact of the directive could be on magnetic resonance imaging (MRI), which is used in hospitals worldwide to produce images of unrivalled quality of the brain and other soft tissues.

Engineering and Design: Soil Vapor Extraction and Bioventing

Science.gov (United States)

2002-06-03

up to 25 mm thick and radiating out from the point of injection as much as 6 meters. A viscous mixture of sand (termed a “proppant”), guar gum gel...be specified and is normally one 42.6-kg (94-lb) bag of cement, (optionally with up to 2.25 kg of bentonite powder ), with less than 18 liters of clean

Persistence of lindane and endosulfan under field conditions in Zambia

International Nuclear Information System (INIS)

Mwangala, F.S.; Mundia, P.M.; Nondo, J.C.; Banda, R.; Mangoye, C.

1997-01-01

The persistence of lindane and endosulfan was studied under field conditions in Zambia in 1992 to 1994. Both pesticides dissipated rapidly under field conditions. About 29% and 73% of initial concentration was lost during the first 30 and 60 days after treatment, respectively in 1992. After 180 days, about 11% of the initial concentration was recovered from the soil. In 1993, 40% of initial residues were lost during the first 30 days. At 180 days after spraying, slightly more residues (25% of the initial values) were recovered at this time than in 1992. This indicated a change in the longer term behaviour of lindane in the soil since the calculated half-lives of lindane, covering the shorter term behaviour, were 55-80 days in 1992 and ∼ 17 days in 1993. In 1994, losses of α-Endosulfan and β-Endosulfan were 40% and 37% respectively during the initial 30 days after treatment. A further 25% of α-Endosulfan and 33% of β-Endosulfan were lost during the following 30 days. These data allow estimates of the half-lives of α- and β-Endosulfan (40 and 38 days) under the field conditions pertaining in Zambia at the time of the trials showing that this compound has only moderate persistence and unlikely to cause long term environmental problems. (author). 7 refs, 8 tabs

Continuous Time Finite State Mean Field Games

International Nuclear Information System (INIS)

Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigão

2013-01-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games

Continuous Time Finite State Mean Field Games

Energy Technology Data Exchange (ETDEWEB)

Gomes, Diogo A., E-mail: dgomes@math.ist.utl.pt [Instituto Superior Tecnico, Center for Mathematical Analysis, Geometry, and Dynamical Systems, Departamento de Matematica (Portugal); Mohr, Joana, E-mail: joana.mohr@ufrgs.br; Souza, Rafael Rigao, E-mail: rafars@mat.ufrgs.br [UFRGS, Instituto de Matematica (Brazil)

2013-08-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N{yields}{infinity} of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games.

Electrostatic ion confinement in a magnetic mirror field

International Nuclear Information System (INIS)

Nishida, Y.; Kawamata, S.; Ishii, K.

1976-08-01

The electrostatic ion stoppering at the mirror point is demonstrated experimentally in a magnetic mirror field. The ion losses from the mirror throat are decreased to about 15% of the initial losses in a rather high plasma density (10 10 0 13 cm -3 ). It is discussed as a confinement mechanism of ions that particles are reflected back adiabatically at the throat of the magnetic mirror field supplemented by DC electric field. (auth.)

Near-field characteristics of highly non-paraxial subwavelength optical fields with hybrid states of polarization

International Nuclear Information System (INIS)

Chen Rui-Pin; Gao Teng-Yue; Chew Khian-Hooi; Dai Chao-Qing; Zhou Guo-Quan; He Sai-Ling

2017-01-01

The vectorial structure of an optical field with hybrid states of polarization (SoP) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions. (paper)

Experimental Investigation of Free Field and Shock-Initiated Implosion of Composite Structures

Science.gov (United States)

2017-02-06

knowledge by examining the pressure pulses emitted in collapse of carbon- fiber reinforced composite tubes and capturing full-field displacements...34:--::-::-=---= 1 2 R c R 0 G (1) Here, E1 and E2 are the longitudinal and transverse moduli, respectively, v12 and v21 are Poisson ’ s ratios of the two major...resin-rich interfibrillar region parallel to the reinforcing fibers . Fractured fibers in underlying plies are also seen in this micrograph, denoted

The analysis of initial Juno magnetometer data using a sparse magnetic field representation

DEFF Research Database (Denmark)

Moore, Kimberly M.; Bloxham, Jeremy; Connerney, John E. P.

2017-01-01

Juno's first perijove pass (PJ1; to within 1.06 RJ of Jupiter's center). We calculate the residuals between the vector magnetic field observations and that calculated using the VIP4 spherical harmonic model and fit these residuals using an elastic net regression. The resulting model demonstrates how...

Hybrid Inflation: Multi-field Dynamics and Cosmological Constraints

Science.gov (United States)

Clesse, Sébastien

2011-09-01

The dynamics of hybrid models is usually approximated by the evolution of a scalar field slowly rolling along a nearly flat valley. Inflation ends with a waterfall phase, due to a tachyonic instability. This final phase is usually assumed to be nearly instantaneous. In this thesis, we go beyond these approximations and analyze the exact 2-field dynamics of hybrid models. Several effects are put in evidence: 1) the possible slow-roll violations along the valley induce the non existence of inflation at small field values. Provided super-planckian fields, the scalar spectrum of the original model is red, in agreement with observations. 2) The initial field values are not fine-tuned along the valley but also occupy a considerable part of the field space exterior to it. They form a structure with fractal boundaries. Using bayesian methods, their distribution in the whole parameter space is studied. Natural bounds on the potential parameters are derived. 3) For the original model, inflation is found to continue for more than 60 e-folds along waterfall trajectories in some part of the parameter space. The scalar power spectrum of adiabatic perturbations is modified and is generically red, possibly in agreement with CMB observations. Topological defects are conveniently stretched outside the observable Universe. 4) The analysis of the initial conditions is extended to the case of a closed Universe, in which the initial singularity is replaced by a classical bounce. In the third part of the thesis, we study how the present CMB constraints on the cosmological parameters could be ameliorated with the observation of the 21cm cosmic background, by future giant radio-telescopes. Forecasts are determined for a characteristic Fast Fourier Transform Telescope, by using both Fisher matrix and MCMC methods.

Axiomatics of Galileo-invariant quantum field theory

International Nuclear Information System (INIS)

Dadashev, L.A.

1986-01-01

The aim of this paper is to construct the axiomatics of Galileo-invariant quantum field theory. The importance of this problem is demonstrated from various points of view: general properties that the fields and observables must satisfy are considered; S-matrix nontriviality of one such model is proved; and the differences from the relativistic case are discussed. The proposed system of axioms is in many respects analogous to Wightman axiomatics, but is less general. The main result is contained in theorems which describe the admissible set of initial fields and total Hamiltonians, i.e., precisely the two entities that completely determine interacting fields. The author considers fields that prove the independence of some axioms

Path integral methods for primordial density perturbations - sampling of constrained Gaussian random fields

International Nuclear Information System (INIS)

Bertschinger, E.

1987-01-01

Path integrals may be used to describe the statistical properties of a random field such as the primordial density perturbation field. In this framework the probability distribution is given for a Gaussian random field subjected to constraints such as the presence of a protovoid or supercluster at a specific location in the initial conditions. An algorithm has been constructed for generating samples of a constrained Gaussian random field on a lattice using Monte Carlo techniques. The method makes possible a systematic study of the density field around peaks or other constrained regions in the biased galaxy formation scenario, and it is effective for generating initial conditions for N-body simulations with rare objects in the computational volume. 21 references

Surfactant-aided recovery/in situ bioremediation for oil-contaminated sites

International Nuclear Information System (INIS)

Ducreaux, J.; Baviere, M.; Seabra, P.; Razakarisoa, O.; Shaefer, G.; Arnaud, C.

1995-01-01

Bioremediation has been the most commonly used method way for in situ cleaning of soils contaminated with low-volatility petroleum products such as diesel oil. However, whatever the process (bioventing, bioleaching, etc.), it is a time-consuming technique that may be efficiency limited by both accessibility and too high concentrations of contaminants. A currently developed process aims at quickly recovering part of the residual oil in the vadose and capillary zones by surfactant flushing, then activating in situ biodegradation of the remaining oil in the presence of the same or other surfactants. The process has been tested in laboratory columns and in an experimental pool, located at the Institut Franco-Allemand de Recherche sur l'Environnement (IFARE) in Strasbourg, France. Laboratory column studies were carried out to fit physico-chemical and hydraulic parameters of the process to the field conditions. The possibility of recovering more than 80% of the oil in the flushing step was shown. For the biodegradation step, forced aeration as a mode of oxygen supply, coupled with nutrient injection aided by surfactants, was tested

Multilevel soil-vapor extraction test for heterogeneous soil

International Nuclear Information System (INIS)

Widdowson, M.A.; Haney, O.R.; Reeves, H.W.

1997-01-01

The design, performance, and analysis of a field method for quantifying contaminant mass-extraction rates and air-phase permeability at discrete vertical locations of the vadose zones are presented. The test configuration consists of a multiscreen extraction well and multilevel observation probes located in soil layers adjacent to the extraction well. For each level tested an inflatable packer system is used to pneumatically isolate a single screen in the extraction well, and a vacuum is applied to induce air flow through the screen. Test data include contaminant concentration and flow characteristics at the extraction well, and transient or steady-state pressure drawdown data at observation probes located at variable radii from the extraction well. The test method is applicable to the design of soil-vapor extraction (SVE) and bioventing remediation systems in a variety of geologic settings, particularly stratified soils. Application of the test method at a gasoline-polluted site located in the Piedmont physiographic region is described. Contaminant mass-extraction rates, expressed in terms of volatile hydrocarbons, varied from 0.16 to 14 kg/d

Assessment of a biological in situ remediation

International Nuclear Information System (INIS)

Wuerdemann, H.; Lund, N.C.; Gudehus, G.

1995-01-01

A field experiment using a bioventing technique has been conducted at the center of contamination at a former gasworks site for 3 years. The emphasis of this investigation is to determine the efficiency of in situ remediation. Due to an extremely heterogeneous distribution of contamination it was impossible to satisfactorily quantify the reduction of hydrocarbons. However, a comparison of highly contaminated soil samples shows a qualitative alteration. The analyses of pollutant composition reveal a significant decrease of low condensed PAHs up to anthracene. The relative increase of high condensed PAHs in the contaminant composition indicates a PAH degradation of 54%. Soil respiration is used to assess the course of remediation. Continuous monitoring of O 2 and CO 2 in the used air leads to an amount of about 2,400 kg of decomposed organics. Large-scale elution tests show a reduction of the sum parameters for the organic pollution of the flushing water of 80%. The PAHs have dropped about 97%. The Microtox test indicates a detoxification of 98%

Discharge initiation experiments in the Tokapole II tokamak

International Nuclear Information System (INIS)

Shepard, D.A.

1984-06-01

Experiments in the Tokapole II tokamak demonstrate the benefits of high density (n/sub e//n 0 greater than or equal to 0.01) preionization by reducing four quantities at startup: necessary toroidal loop voltage (V 1 ) (50%), volt-second consumption (40 to 50%), impurity radiation (25 to 50%), and runaway electron production (approx. 80 to 100%). A zero-dimensional code models the loop voltage reduction dependence on preionization density and predicts a similar result for reactor scale devices. The code shows low initial resistivity and a high resistivity time derivative contribute to loop voltage reduction. The power balance of the ECR plasma in a toroidal-field-only case was studied. Langmuir probes and impurity doping were used. The vertical electric field (E/sub v/) and current (I/sub v/), which result from curvature drift, were measured (E/sub v/ approx. 10 V/cm and I/sub v/ approx. 50 Amps) and exceeded expected values for the bulk electron temperature (approx. 10 eV). A series of experiments with external windings to simulate field errors perpendicular to the toroidal field was done. The results imply that an error field of 0.1% of the toroidal field is deleterious to ECR plasma density

Classical and quantum initial conditions for Higgs inflation

Directory of Open Access Journals (Sweden)

Alberto Salvio

2015-11-01

Full Text Available We investigate whether Higgs inflation can occur in the Standard Model starting from natural initial conditions or not. The Higgs has a non-minimal coupling to the Ricci scalar. We confine our attention to the regime where quantum Einstein gravity effects are small in order to have results that are independent of the ultraviolet completion of gravity. At the classical level we find no tuning is required to have successful Higgs inflation, provided the initial homogeneity condition is satisfied. On the other hand, at the quantum level we obtain that the renormalization for large non-minimal coupling requires an additional degree of freedom, unless a tuning of the initial values of the running parameters is made. In order to see that this effect may change the predictions we finally include such degree of freedom in the field content and show that Starobinsky's R2 inflation dominates over Higgs inflation.

Singularity, initial conditions and quantum tunneling in modern cosmology

International Nuclear Information System (INIS)

Khalatnikov, I M; Kamenshchik, A Yu

1998-01-01

The key problems of modern cosmology, such as the cosmological singularity, initial conditions, and the quantum tunneling hypothesis, are discussed. The relationship between the latest cosmological trends and L D Landau's old ideas is analyzed. Particular attention is given to the oscillatory approach to singularity; quantum tunneling processes determining wave function of the Universe in the presence of a compex scalar field; and the role of quantum corrections in these processes. The classical dynamics of closed models with a real scalar field is investigated from the standpoint of chaotic, fractal, and singularity-avoiding properties. (special issue)

Lab, Field, Gallery and Beyond

DEFF Research Database (Denmark)

Binder, Thomas; Koskinen, Ilpo; Redström, Johan

2009-01-01

Over the last ten years we have seen a growing number of researchers integrating design experiments in their research inquiries. Initially, this work borrowed heavily from neighboring fields, employing a dual strategy in which design experiments and their evaluation were largely treated as separate...... processes that were often carried out by different people. More recently, design researchers have developed several approaches that integrate design-specific work methods to research. This paper takes a methodological look at three such established approaches that we call Lab, Field, and Gallery. We...

Soil stabilization field trial : final report.

Science.gov (United States)

2006-01-01

A five-year study was initiated seeking materials/additives and procedures that help to mitigate : crack susceptibility in cement-treated material (CTM). A field test program of six 305-m (1000-ft) test : sections was implemented in August 2000. The ...

Site remediation using biological processes

International Nuclear Information System (INIS)

Lei, J.; Sansregret, J.L.; Cyr, B.; Pouliot, Y.

1995-01-01

The main process used in the bioremediation of contaminated sites is the microbial degradation and mineralization of pollutants. The bioengineering processes developed and applied by the company to optimize the microbial degradation are described and full scale case studies are reviewed. In each case, the site characteristics (type of contaminants, nature of soil, geographic location, etc.) and the results obtained are presented. The selected projects cover different bioremediation techniques (biopile, bioventing and air sparging), different contaminants (PAH, PCP, hydrocarbons) and different types of industrial sites (former gas work plant, petroleum depot, refinery, etc.)

Quantum processes: A Whiteheadian interpretation of quantum field theory

Science.gov (United States)

Bain, Jonathan

Quantum processes: A Whiteheadian interpretation of quantum field theory is an ambitious and thought-provoking exercise in physics and metaphysics, combining an erudite study of the very complex metaphysics of A.N. Whitehead with a well-informed discussion of contemporary issues in the philosophy of algebraic quantum field theory. Hättich's overall goal is to construct an interpretation of quantum field theory. He does this by translating key concepts in Whitehead's metaphysics into the language of algebraic quantum field theory. In brief, this Hättich-Whitehead (H-W, hereafter) interpretation takes "actual occasions" as the fundamental ontological entities of quantum field theory. An actual occasion is the result of two types of processes: a "transition process" in which a set of initial possibly-possessed properties for the occasion (in the form of "eternal objects") is localized to a space-time region; and a "concrescence process" in which a subset of these initial possibly-possessed properties is selected and actualized to produce the occasion. Essential to these processes is the "underlying activity", which conditions the way in which properties are initially selected and subsequently actualized. In short, under the H-W interpretation of quantum field theory, an initial set of possibly-possessed eternal objects is represented by a Boolean sublattice of the lattice of projection operators determined by a von Neumann algebra R (O) associated with a region O of Minkowski space-time, and the underlying activity is represented by a state on R (O) obtained by conditionalizing off of the vacuum state. The details associated with the H-W interpretation involve imposing constraints on these representations motivated by principles found in Whitehead's metaphysics. These details are spelled out in the three sections of the book. The first section is a summary and critique of Whitehead's metaphysics, the second section introduces the formalism of algebraic quantum field

Optical Emissions of Sprite Streamers in Weak Electric Fields

Science.gov (United States)

Liu, N.; Pasko, V. P.

2004-12-01

Sprites commonly consist of large numbers of needle-shaped filaments of ionization [e.g., Gerken and Inan, JASTP, 65, 567, 2003] and typically initiate at altitudes 70-75 km in a form of upward and downward propagating streamers [Stanley et al., GRL, 26, 3201, 1999; Stenbaek-Nielsen et al., GRL, 27, 3829, 2000; McHarg et al., JGR, 107, 1364, 2002; Moudry et al., JASTP, 65, 509, 2003]. The strong electric fields E exceeding the conventional breakdown threshold field Ek are needed for initiation of sprite streamers from single electron avalanches and recent modeling studies indicate that streamers propagating in fields E>Ek experience strong acceleration and expansion in good agreement with the above cited observations [Liu and Pasko, JGR, 109, A04301, 2004]. The initiated streamers are capable of propagating in fields substantially lower than Ek [Allen and Ghaffar, J. Phys. D: Appl. Phys., 28, 331, 1995] and it is expected that a significant part of sprite optical output comes from regions with EEk). Additionally, the values of electric fields inside of the streamer channel are always well below Ek and since the excitation coefficients for optical emissions are very sensitive to the driving electric field magnitude most of the optical luminosity of streamers in this case arises from streamer tips, indicating that observed streamer filaments in many cases may be produced by time averaging of optical luminosity coming from localized regions around streamer tips as streamers move through an instrument's field of view. We will discuss pressure dependent differences of optical emissions at different sprite altitudes, and important similarities between observed sprite streamers and recent time resolved (van Veldhuizen et al., IEEE Trans. Plasma Sci., 30, 162, 2002; Yi and Williams, J. Phys. D. Appl. Phys., 35, 205, 2002].

Measurements of Rayleigh-Taylor-Induced Magnetic Fields in the Linear and Non-linear Regimes

Science.gov (United States)

Manuel, Mario

2012-10-01

Magnetic fields are generated in plasmas by the Biermann-battery, or thermoelectric, source driven by non-collinear temperature and density gradients. The ablation front in laser-irradiated targets is susceptible to Rayleigh-Taylor (RT) growth that produces gradients capable of generating magnetic fields. Measurements of these RT-induced magnetic fields in planar foils have been made using a combination of x-ray and monoenergetic-proton radiography techniques. At a perturbation wavelength of 120 μm, proton radiographs indicate an increase of the magnetic-field strength from ˜1 to ˜10 Tesla during the linear growth phase. A characteristic change in field structure was observed later in time for irradiated foils of different initial surface perturbations. Proton radiographs show a regular cellular configuration initiated at the same time during the drive, independent of the initial foil conditions. This non-linear behavior has been experimentally investigated and the source of these characteristic features will be discussed.

Initiating Service Encounter-based Innovation by Word-of-Business

DEFF Research Database (Denmark)

Mattsson, Jan

2015-01-01

Purpose – This paper aims to set up a natural experiment as action research and to develop a framework of cognitive distance of informants to improve the initiation of service encounter-based innovation. Design/methodology/approach – Natural experiment as action research in one Scandinavian case...... transcriptions of interviews and transcriptions. Research limitations/implications – Only one Scandinavian company and a limited number of informants were activated. Also, the time period only included the initiation phase of service encounter-based innovation. Practical implications – Three different strategies...... in an emerging innovation field, open/user-driven innovation. Theory from business marketing, service encounter and innovation is also used....

Diversity in laboratory animal science: issues and initiatives.

Science.gov (United States)

Alworth, Leanne; Ardayfio, Krystal L; Blickman, Andrew; Greenhill, Lisa; Hill, William; Sharp, Patrick; Talmage, Roberta; Plaut, Victoria C; Goren, Matt

2010-03-01

Since diversity in the workplace began receiving scholarly attention in the late 1980s, many corporations and institutions have invested in programs to address and manage diversity. We encourage laboratory animal science to address the challenges and to build on the strengths that personal diversity brings to our field and workplaces. Diversity is already becoming increasingly relevant in the workplace and the laboratory animal science field. By addressing issues related to diversity, laboratory animal science could benefit and potentially fulfill its goals more successfully. To date, diversity has received minimal attention from the field as a whole. However, many individuals, workplaces, and institutions in industry, academia, and the uniformed services that are intimately involved with the field of laboratory animal science are actively addressing issues concerning diversity. This article describes some of these programs and activities in industry and academia. Our intention is that this article will provide useful examples of inclusion-promoting activities and prompt further initiatives to address diversity awareness and inclusion in laboratory animal science.

Meromorphic Vector Fields and Circle Packings

DEFF Research Database (Denmark)

Dias, Kealey

The objective of the Ph.D. project is to initiate a classification of bifurcations of meromorphic vector fields and to clarify their relation to circle packings. Technological applications are to image analysis and to effective grid generation using discrete conformal mappings. The two branches...... of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions or meromorphic (allowing poles...... as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic vector fields. Restricting...

Whole-Home Dehumidifiers: Field-Monitoring Study

Energy Technology Data Exchange (ETDEWEB)

Burke, Tom; Willem, Henry; Ni, Chun Chun; Stratton, Hannah; Whitehead, Camilla Dunham; Johnson, Russell

2014-09-23

Lawrence Berkeley National Laboratory (LBNL) initiated a WHD field-metering study to expand current knowledge of and obtain data on WHD operation and energy consumption in real-world applications. The field study collected real-time data on WHD energy consumption, along with information regarding housing characteristics, consumer behavior, and various outdoor conditions expected to affect WHD performance and efficiency. Although the metering study collected similar data regarding air conditioner operation, this report discusses only WHDs. The primary objectives of the LBNL field-metering study are to (1) expand knowledge of the configurations, energy consumption profiles, consumer patterns of use (e.g., relative humidity [RH] settings), and environmental parameters of whole-home dehumidification systems; and (2) develop distributions of hours of dehumidifier operation in four operating modes: off, standby, fan-only, and compressor (also called dehumidification mode). Profiling energy consumption entails documenting the power consumption, duration of power consumption in different modes, condensate generation, and properties of output air of an installed system under field conditions of varying inlet air temperature and RH, as well as system configuration. This profiling provides a more detailed and deeper understanding of WHD operation and its complexities. This report describes LBNL’s whole-home dehumidification field-metering study conducted at four homes in Wisconsin and Florida. The initial phase of the WHD field-metering study was conducted on one home in Madison, Wisconsin, from June to December of 2013. During a second phase, three Florida homes were metered from June to October of 2014. This report presents and examines data from the Wisconsin site and from the three Florida sites.

Continuous time finite state mean field games

KAUST Repository

Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigã o

2013-01-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.

Continuous time finite state mean field games

KAUST Repository

Gomes, Diogo A.

2013-04-23

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.

Biological actions and effects of low-frequency fields

International Nuclear Information System (INIS)

Brix, J.

1993-01-01

Cell culture studies have shown that low-frequency electromagnetic fields may affect cell behaviour. The fact that the corresponding field strengths are too weak to affect membrane potential, suggests that these fields trigger enzymatic reactions at the outer face of the membrane, i.e. cell-intrinsic reaction cascades and a biological modification of the affected biological system take place. These are working models and hypotheses which need to substantiated by further studies in this field. Epidemiological studies suggest that electromagnetic fields influence cancer development in man. However there is no action model indicating exposure to fields to be a genotoxic agent possible triggering a direct genetic modification which precludesr any initialization. (orig.) [de

Exploring Proposals for Resolving the Initial Conditions and Multiverse Problems in Inflation

Science.gov (United States)

Panithanpaisal, Nondh; Steinhardt, Paul

2018-01-01

The theory of cosmic inflation with the plateau-like potentials for the scalar field is very successful in predicting standard cosmological parameters. However, if the quantum effects are included, the theory inherently contains serious problems, namely, the multiverse problem and the initial conditions problem. It has been suggested in Mukhanov 2015 and Deen et al. 2016 to add a potential wall to the potential, so that the field never reaches the self-reproduction point. We examine these two proposals by varying the positions of the potential wall as well as varying the initial ratios of kinetic energy, potential energy and curvature. We demonstrate that both proposals are fine-tuned, at best, as they suffer from the drift in the predictions of the spectral tilt (ns) and the tensor-to-scalar ratio (r).

Wind field forecast for accidental release of radiative materials

International Nuclear Information System (INIS)

Kang Ling; Chen Jiayi; Cai Xuhui

2003-01-01

A meso-scale wind field forecast model was designed for emergency environmental assessment in case of accidental release of radiative materials from a nuclear power station. Actual practice of the model showed that it runs fast, has wind field prediction function, and the result given is accurate. With meteorological data collected from weather stations, and pre-treated by a wind field diagnostic model, the initial wind fields at different times were inputted as initial values and assimilation fields for the forecasting model. The model, in turn, worked out to forecast meso-scale wind field of 24 hours in a horizontal domain of 205 km x 205 km. And then, the diagnostic model was employed again with the forecasting data to obtain more detail information of disturbed wind field by local terrain in a smaller domain of 20.5 km x 20.5 km, of which the nuclear power station is at the center. Using observation data in January, April, July and October of 1996 over the area of Hangzhou Bay, wind fields in these 4 months were simulated by different assimilation time and number of the weather stations for a sensitive test. Results indicated that the method used here has increased accuracy of the forecasted wind fields. And incorporating diagnostic method with the wind field forecast model has greatly increased efficiency of the wind field forecast for the smaller domain. This model and scheme have been used in Environmental Consequence Assessment System of Nuclear Accident in Qinshan Area

Analysis on the Initial Cracking Parameters of Cross-Measure Hydraulic Fracture in Underground Coal Mines

Directory of Open Access Journals (Sweden)

Yiyu Lu

2015-07-01

Full Text Available Initial cracking pressure and locations are important parameters in conducting cross-measure hydraulic fracturing to enhance coal seam permeability in underground coalmines, which are significantly influenced by in-situ stress and occurrence of coal seam. In this study, stress state around cross-measure fracturing boreholes was analyzed using in-situ stress coordinate transformation, then a mathematical model was developed to evaluate initial cracking parameters of borehole assuming the maximum tensile stress criterion. Subsequently, the influences of in-situ stress and occurrence of coal seams on initial cracking pressure and locations in underground coalmines were analyzed using the proposed model. Finally, the proposed model was verified with field test data. The results suggest that the initial cracking pressure increases with the depth cover and coal seam dip angle. However, it decreases with the increase in azimuth of major principle stress. The results also indicate that the initial cracking locations concentrated in the second and fourth quadrant in polar coordinate, and shifted direction to the strike of coal seam as coal seam dip angle and azimuth of maximum principle stress increase. Field investigation revealed consistent rule with the developed model that the initial cracking pressure increases with the coal seam dip angle. Therefore, the proposed mathematical model provides theoretical insight to analyze the initial cracking parameters during cross-measure hydraulic fracturing for underground coalmines.

Wind laws for shockless initialization. [numerical forecasting model

Science.gov (United States)

Ghil, M.; Shkoller, B.

1976-01-01

A system of diagnostic equations for the velocity field, or wind laws, was derived for each of a number of models of large-scale atmospheric flow. The derivation in each case is mathematically exact and does not involve any physical assumptions not already present in the prognostic equations, such as nondivergence or vanishing of derivatives of the divergence. Therefore, initial states computed by solving these diagnostic equations should be compatible with the type of motion described by the prognostic equations of the model and should not generate initialization shocks when inserted into the model. Numerical solutions of the diagnostic system corresponding to a barotropic model are exhibited. Some problems concerning the possibility of implementing such a system in operational numerical weather prediction are discussed.

Diagnosis of initial changes in patients suffering from rheumatoid arthritis. A comparison between low-field magnetic resonance imaging, 3-phase bone scintigraphy and conventional X-ray

International Nuclear Information System (INIS)

Hoepfner, S.; Dresel, S.; Weiss, M.; Hahn, K.; Treitl, M.; Krolak, C.; Becker-Gaab, C.; Schattenkirchner, M.

2002-01-01

Besides conventional X-rays, in the diagnostic work up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The aim of this study was to compare the diagnostic value of the newly developed low field MRI with the proven methods X-rays and 3P-Sz. Methods: 65 patients (47f, 18m; 20-86 yrs) were studied on a one day protocol with 3P-Sz (550 MBq Tc-99m DPD), MRI and X-rays of the hands. Images were visually analysed by two blinded nuclear medicine physicians and radiologists and classified as a) RA-typical, b) inflammatory, non-RA-typical and c) non inflammatory changes. All methods were compared to 3P-Sz as golden standard. Results: In comparison to 3P-Sz, low field MRI presents with almost equal sensitivity and specificity in rheumatoid-typical and inflammatory changes. Conventional X-rays revealed in arthritis-typical changes as well as in inflammatory changes a significantly lower sensitivity and also a lower negative predictive value while specificity equals the one of MRI. Quantitative analysis of 3P-Sz using ROI-technique unveiled significantly higher values in patients with rheumatoid arthritis than in those with no inflammatory changes. Conclusion: MRI represents an equally sensitive method in the initial diagnosis of rheumatoid-typical and inflammatory changes in the region of the hands as compared to the 3P-Sz. Besides the basic diagnosis with conventional X-rays, 3P-Sz is still the recommended method of choice to evaluate the whole body when RA is suspected. Additionally, quantitative analysis of the 3P-Sz using the ROI technique in the region of the hands reveals statistically significant results and should therefore be taken into account in the assessment of inflammatory changes. (orig.) [de

Initial Field Trial of a Coach-Supported Web-Based Depression Treatment.

Science.gov (United States)

Schueller, Stephen M; Mohr, David C

2015-08-01

Early web-based depression treatments were often self-guided and included few interactive elements, instead focusing mostly on delivering informational content online. Newer programs include many more types of features. As such, trials should analyze the ways in which people use these sites in order to inform the design of subsequent sites and models of support. The current study describes of a field trial consisting of 9 patients with major depressive disorder who completed a 12-week program including weekly coach calls. Patients usage varied widely, however, patients who formed regular patterns tended to persist with the program for the longest. Future sites might be able to facilitate user engagement by designing features to support regular use and to use coaches to help establish patterns to increase long-term use and benefit.

On multiplying methods in the field of research evaluation

Energy Technology Data Exchange (ETDEWEB)

Derrick, G.; Molas-Gallart, J.; De Rijcke, S.; Meijer, I.; Van der Weijden, I.; Wouters, P.

2016-07-01

This special session forms part of a larger program aimed at the multiplication and integration of methodological approaches in the research evaluation and innovation policy field. The session builds on previous initiatives by Gemma Derrick and colleagues at CWTS, INGENIO, the Rathenau Instituut and SPRU, exploring the advantages of qualitative methodological tools at the STI/ENID conference in Lugano, and an international workshop in London in October 2015. The program is highly topical: the research evaluation field is currently reconsidering its methodological foundations in light of new research questions arising from policy initiatives regarding a) the move toward open science; b) a reconceptualization of research excellence to include societal relevance; c) diversification of academic careers, and d) the search for indicators showcasing responsible research behavior and innovation. This new special session at STI2016 will advance and broaden the scope of previous initiatives by building bridges between cutting edge research involving quantitative, qualitative, and mixed methodological research designs. Bringing together leading experts and promising researchers with distinctive methodological skill-sets, the session will demonstrate the advantages of cross-fertilization between ‘core’ and ‘peripheral’ methodological approaches for the research evaluation and science indicators field. (Author)

Chemical, Biological, Radiological and Nuclear Regional Centres of Excellence Initiative

International Nuclear Information System (INIS)

Bril, L.V.

2013-01-01

This series of slides presents the initiative launched in May 2010 by the European Union to develop at national and regional levels the necessary institutional capacity to fight against the CBRN (Chemical, Biological, Radiological and Nuclear) risk. The origin of the risk can be: -) criminal (proliferation, theft, sabotage and illicit traffics), -) accidental (industrial catastrophes, transport accidents...) and -) natural (mainly pandemics). The initiative consists in the creation of Centres of Excellence for providing assistance and cooperation in the field of CBRN risk and the creation of experts networks for sharing best practices, reviewing laws and regulation, developing technical capacities in order to mitigate the CBRN risk. The initiative is complementary to the instrument for nuclear safety cooperation. Regional Centres of Excellence are being set up in 6 regions: South East Europe, South East Asia, North Africa, West Africa, Middle East, and Central Asia covering nearly 40 countries. A global budget of 100 million Euros will be dedicated to this initiative for the 2009-2013 period. (A.C.)

Electromagnetic field effects in explosives

Science.gov (United States)

Tasker, Douglas

2009-06-01

Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: measurements of conductivity; enhancement of performance; and control of initiation and growth of reaction. Hayes...()^1 showed a strong correlation of peak electrical conductivity with carbon content of the detonation products. Ershov.......^2 linked detailed electrical conductivity measurements with reaction kinetics and this work was extended to enhance detonation performance electrically;...^3 for this, electrical power densities of the order of 100 TW/m^2 of explosive surface normal to the detonation front were required. However, small electrical powers are required to affect the initiation and growth of reaction.......^4,5 A continuation of this work will be reported. LA-UR 09-00873 .^1 B. Hayes, Procs. of 4th Symposium (International) on Detonation (1965), p. 595. ^2 A. Ershov, P. Zubkov, and L. Luk'yanchikov, Combustion, Explosion, and Shock Waves 10, 776-782 (1974). ^3 M. Cowperthwaite, Procs. 9th Detonation Symposium (1989), p. 388-395. ^4 M. A. Cook and T. Z. Gwyther, ``Influence of Electric Fields on Shock to Detonation Transition,'' (1965). ^5 D. Salisbury, R. Winter, and L. Biddle, Procs. of the APS Topical Conference on Shock Compression of Condensed Matter (2005) p. 1010-1013.

Statistics of peaks in cosmological nonlinear density fields

International Nuclear Information System (INIS)

Suginohara, Tatsushi; Suto, Yasushi.

1990-06-01

Distribution of the high-density peaks in the universe is examined using N-body simulations. Nonlinear evolution of the underlying density field significantly changes the statistical properties of the peaks, compared with the analytic results valid for the random Gaussian field. In particular, the abundances and correlations of the initial density peaks are discussed in the context of biased galaxy formation theory. (author)

Time dependent convection electric fields and plasma injection

International Nuclear Information System (INIS)

Kaye, S.M.; Kivelson, M.G.

1979-01-01

Large-scale electric fields associated with storms or substorms are responsible for inward convection and energization of plasma sheet plasma. Calculations based on steady state convection theory show that the response to such electric fields qualitatively accounts for many features of the injected particle distribution, but quantitative agreement with the theory has not yet been obtained. It is known that the predictions can be improved by introducing the concept of convection in response to a time dependent electric field. On the other hand, time dependent calculations are sensitive to the choice of initial conditions, and most models have failed to incorporate these conditions in a realistic and self-consistent manner. In this paper we present a more complete model consisting of realisic initial conditions and time dependent convection to explain a typical substorm-associated electron injection event. We find very good agreement between the observed electron flux changes and those predicted by our model

Funding Initiatives | Women in Science | Initiatives | Indian Academy ...

Indian Academy of Sciences (India)

Home; Initiatives; Women in Science; Funding Initiatives ... The Fellowship Scheme for Women Scientists for societal programmes is initiative of the ... at a young age of 52, after a valiant battle with cancer, today on 29th March 2016 in Delhi.

Testing the initial-final mass relationship of white dwarfs

International Nuclear Information System (INIS)

Catalan, S; Isern, J; Garcia-Berro, E; Ribas, I

2009-01-01

In this contribution we revisit the initial-final mass relationship of white dwarfs, which links the mass of a white dwarf with that of its progenitor in the main-sequence. Although this function is of paramount importance to several fields in modern astrophysics, it is still not well constrained either from the theoretical or the observational points of view. We present here a revision of the present semi-empirical initial-final mass relationship using all the available data and including our recent results obtained from studying white dwarfs in common proper motion pairs. We have also analyzed the results obtained so far to provide some clues on the dependence of this relationship on metallicity. Finally, we have also performed an indirect test of the initial-final mass relationship by studying its effect on the luminosity function and on the mass distribution of white dwarfs.

Impact ionization dynamics in silicon by MV/cm THz fields

DEFF Research Database (Denmark)

Tarekegne, Abebe Tilahun; Hirori, Hideki; Tanaka, Koichiro

2017-01-01

We investigate the dynamics of the impact ionization (IMI) process in silicon in extremely high fields in the MV/cm range and at low initial carrier concentrations; conditions that are not accessible with conventional transport measurements. We use ultrafast measurements with high-intensity terah......We investigate the dynamics of the impact ionization (IMI) process in silicon in extremely high fields in the MV/cm range and at low initial carrier concentrations; conditions that are not accessible with conventional transport measurements. We use ultrafast measurements with high......-intensity terahertz pulses to show that IMI is significantly more efficient at lower than at higher initial carrier densities. Specifically, in the case of silicon with an intrinsic carrier concentration (∼1010 cm−3), the carrier multiplication process can generate more than 108 electrons from just a single free...

Parsec-scale Obscuring Accretion Disk with Large-scale Magnetic Field in AGNs

Energy Technology Data Exchange (ETDEWEB)

Dorodnitsyn, A.; Kallman, T. [Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD, 20771 (United States)

2017-06-10

A magnetic field dragged from the galactic disk, along with inflowing gas, can provide vertical support to the geometrically and optically thick pc-scale torus in AGNs. Using the Soloviev solution initially developed for Tokamaks, we derive an analytical model for a rotating torus that is supported and confined by a magnetic field. We further perform three-dimensional magneto-hydrodynamic simulations of X-ray irradiated, pc-scale, magnetized tori. We follow the time evolution and compare models that adopt initial conditions derived from our analytic model with simulations in which the initial magnetic flux is entirely contained within the gas torus. Numerical simulations demonstrate that the initial conditions based on the analytic solution produce a longer-lived torus that produces obscuration that is generally consistent with observed constraints.

Initial education and training pathways for danish adult educators

DEFF Research Database (Denmark)

Milana, Marcella

2008-01-01

The contribution aims at mapping out initial education and training opportunities for Danish adult educators and to examine key structural features that characterise professionalisation processes in the field of adult education. The analysis draws on policy documents and available research...... three provides a detailed account of existing qualification pathways for individuals willing to enter the system as adult educators. Notwithstanding the range of opportunities to acquire pedagogical qualifications in teaching adults, the knowledge and skills provided may vary substantially. Consequently......, the author's main argument is that it is not possible to speak of tailored-made pathways of professionalisation in the field of adult education, at least in the Danish context....

The Field Lysimeter Test Facility (FLTF) at the Hanford Site: Installation and initial tests

International Nuclear Information System (INIS)

Gee, G.W.; Kirkham, R.R.; Downs, J.L.; Campbell, M.D.

1989-02-01

The objectives of this program are to test barrier design concepts and to demonstrate a barrier design that meets established performance criteria for use in isolating wastes disposed of near-surface at the Hanford Site. Specifically, the program is designed to assess how well the barriers perform in controlling biointrusion, water infiltration, and erosion, as well as evaluating interactions between environmental variables and design factors of the barriers. To assess barrier performance and design with respect to infiltration control, field lysimeters and small- and large-scale field plots are planned to test the performance of specific barrier designs under actual and modified (enhanced precipitation) climatic conditions. The Field Lysimeter Test Facility (FLTF) is located in the 600 Area of the Hanford Site just east of the 200 West Area and adjacent to the Hanford Meteorological Station. The FLTF data will be used to assess the effectiveness of selected protective barrier configurations in controlling water infiltration. The facility consists of 14 drainage lysimeters (2 m dia x 3 m deep) and four precision weighing lysimeters (1.5 m x 1.5 m x 1.7 m deep). The lysimeters are buried at grade and aligned in a parallel configuration, with nine lysimeters on each side of an underground instrument chamber. The lysimeters were filled with materials to simulate a multilayer protective barrier system. Data gathered from the FLTF will be used to compare key barrier components and to calibrate and test models for predicting long-term barrier performance

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.A. [Sandia National Labs., Albuquerque, NM (United States); Case, J.B.; Tyburski, J.R. [I. T. Corp., Albuquerque, NM (United States)

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application.

Discharge initiation experiments in the Tokapole II tokamak

International Nuclear Information System (INIS)

Shepard, D.A.

1984-01-01

Experiments in the Tokapole II tokamak demonstrate the benefits of high density (n/sub e//n/sub o/ greater than or equal to 0.01) preionization by reducing four quantities at startup: necessary toroidal loop voltage (V 1 ) (50%), volt-second consumption (40-50%), impurity radiation (25-50%), and runaway electron production (approx. 80-100%). A zero-dimensional code models the loop voltage reduction dependence on preionization density and predicts a similar result for reactor scale devices. The code shows low initial resistivity and a high resistivity time derivative contribute to loop voltage reduction. Microwaves at the electron cyclotron resonance (ECR) frequency and plasma gun injection produce high density preionization, which reduces the initial V 1 , volt-second consumption, and runaways. The ECR preionization also reduces impurity radiation by shortening the time from voltage application to current channel formation. This, evidently, reduces the total plasma-wall interaction at startup. The power balance of the ECR plasma in a toroidal-field-only case was studied using Langmuir probes and impurity doping. The vertical electric field and current, which result from curvature drift, were measured as approx. 10 V/cm and 50 amps, respectively, and exceeded expected values for the bulk electron temperature (approx. 10 eV)

Anisotropy in wavelet-based phase field models

KAUST Repository

Korzec, Maciek; Mü nch, Andreas; Sü li, Endre; Wagner, Barbara

2016-01-01

When describing the anisotropic evolution of microstructures in solids using phase-field models, the anisotropy of the crystalline phases is usually introduced into the interfacial energy by directional dependencies of the gradient energy coefficients. We consider an alternative approach based on a wavelet analogue of the Laplace operator that is intrinsically anisotropic and linear. The paper focuses on the classical coupled temperature/Ginzburg--Landau type phase-field model for dendritic growth. For the model based on the wavelet analogue, existence, uniqueness and continuous dependence on initial data are proved for weak solutions. Numerical studies of the wavelet based phase-field model show dendritic growth similar to the results obtained for classical phase-field models.

Anisotropy in wavelet-based phase field models

KAUST Repository

Korzec, Maciek

2016-04-01

When describing the anisotropic evolution of microstructures in solids using phase-field models, the anisotropy of the crystalline phases is usually introduced into the interfacial energy by directional dependencies of the gradient energy coefficients. We consider an alternative approach based on a wavelet analogue of the Laplace operator that is intrinsically anisotropic and linear. The paper focuses on the classical coupled temperature/Ginzburg--Landau type phase-field model for dendritic growth. For the model based on the wavelet analogue, existence, uniqueness and continuous dependence on initial data are proved for weak solutions. Numerical studies of the wavelet based phase-field model show dendritic growth similar to the results obtained for classical phase-field models.

Dynamics of Dust in a Plasma Sheath with Magnetic Field

International Nuclear Information System (INIS)

Duan Ping; Liu Jinyuan; Gon Ye; Liu Yue; Wang Xiaogang

2007-01-01

Dynamics of dust in a plasma sheath with a magnetic field was investigated using a single particle model. The result shows that the radius, initial position, initial velocity of the dust particles and the magnetic field do effect their movement and equilibrium position in the plasma sheath. Generally, the dust particles with the same size, whatever original velocity and position they have, will locate at the same position in the end under the net actions of electrostatic, gravitational, neutral collisional, and Lorentz forces. But the dust particles will not locate in the plasma sheath if their radius is beyond a certain value

Coherent and Semiclassical States of a Charged Particle in a Constant Electric Field

Science.gov (United States)

Adorno, T. C.; Pereira, A. S.

2018-05-01

The method of integrals of motion is used to construct families of generalized coherent states of a nonrelativistic spinless charged particle in a constant electric field. Families of states, differing in the values of their standard deviations at the initial time, are obtained. Depending on the initial values of the standard deviations, and also on the electric field, it turns out to be possible to identify some families with semiclassical states.

Out-of-Field Cell Survival Following Exposure to Intensity-Modulated Radiation Fields

International Nuclear Information System (INIS)

Butterworth, Karl T.; McGarry, Conor K.; Trainor, Colman; O'Sullivan, Joe M.; Hounsell, Alan R.; Prise, Kevin M.

2011-01-01

Purpose: To determine the in-field and out-of-field cell survival of cells irradiated with either primary field or scattered radiation in the presence and absence of intercellular communication. Methods and Materials: Cell survival was determined by clonogenic assay in human prostate cancer (DU145) and primary fibroblast (AGO1552) cells following exposure to different field configurations delivered using a 6-MV photon beam produced with a Varian linear accelerator. Results: Nonuniform dose distributions were delivered using a multileaf collimator (MLC) in which half of the cell population was shielded. Clonogenic survival in the shielded region was significantly lower than that predicted from the linear quadratic model. In both cell lines, the out-of-field responses appeared to saturate at 40%-50% survival at a scattered dose of 0.70 Gy in DU-145 cells and 0.24 Gy in AGO1522 cells. There was an approximately eightfold difference in the initial slopes of the out-of-field response compared with the α-component of the uniform field response. In contrast, cells in the exposed part of the field showed increased survival. These observations were abrogated by direct physical inhibition of cellular communication and by the addition of the inducible nitric oxide synthase inhibitor aminoguanidine known to inhibit intercellular bystander effects. Additional studies showed the proportion of cells irradiated and dose delivered to the shielded and exposed regions of the field to impact on response. Conclusions: These data demonstrate out-of-field effects as important determinants of cell survival following exposure to modulated irradiation fields with cellular communication between differentially irradiated cell populations playing an important role. Validation of these observations in additional cell models may facilitate the refinement of existing radiobiological models and the observations considered important determinants of cell survival.

Model for initiation of quality factor degradation at high accelerating fields in superconducting radio-frequency cavities

International Nuclear Information System (INIS)

Dzyuba, A; Romanenko, A; Cooley, L D

2010-01-01

A model for the onset of the reduction in superconducting radio-frequency (SRF) cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H pen . Such defects were argued to be the worst case by Buzdin and Daumens (1998 Physica C 294 257), whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter κ. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of H pen when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower H pen was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice versa. To test the model with actual data, coupons were prepared by buffered chemical polishing and electropolishing, and stylus profilometry was used to obtain distributions of angles. From these data, curves for surface resistance generated by simple flux flow as a function of magnetic field were generated by integrating over the distribution of angles for reasonable values of κ. This showed that combined effects of roughness and contamination indeed reduce the Q-drop onset field by ∼ 20%, and that contamination contributes to Q-drop as much as roughness. The latter point may be overlooked by SRF cavity research, since access to the cavity interior by spectroscopy tools is very difficult, whereas optical images have become commonplace. The model

Model for initiation of quality factor degradation at high accelerating fields in superconducting radio-frequency cavities

Science.gov (United States)

Dzyuba, A.; Romanenko, A.; Cooley, L. D.

2010-12-01

A model for the onset of the reduction in superconducting radio-frequency (SRF) cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration Hpen. Such defects were argued to be the worst case by Buzdin and Daumens (1998 Physica C 294 257), whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter κ. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of Hpen when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower Hpen was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice versa. To test the model with actual data, coupons were prepared by buffered chemical polishing and electropolishing, and stylus profilometry was used to obtain distributions of angles. From these data, curves for surface resistance generated by simple flux flow as a function of magnetic field were generated by integrating over the distribution of angles for reasonable values of κ. This showed that combined effects of roughness and contamination indeed reduce the Q-drop onset field by ~ 20%, and that contamination contributes to Q-drop as much as roughness. The latter point may be overlooked by SRF cavity research, since access to the cavity interior by spectroscopy tools is very difficult, whereas optical images have become commonplace. The model was

Field reversal produced by a plasma gun

International Nuclear Information System (INIS)

Hartman, C.W.; Condit, W.; Granneman, E.H.A.; Prono, D.; Smith, A.C. Jr.; Taska, J.; Turner, W.C.

1980-01-01

Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode

Role of initial depth at basin margins in sequence architecture: field examples and computer models

Czech Academy of Sciences Publication Activity Database

Uličný, David; Nichols, G.; Waltham, D.

2002-01-01

Roč. 14, č. 3 (2002), s. 347-360 ISSN 0950-091X R&D Projects: GA ČR GA205/01/0629 Institutional research plan: CEZ:AV0Z3012916 Keywords : basin margin * initial depth * sedimentation * depositional sequences Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.022, year: 2002

Avoiding the blue spectrum and the fine-tuning of initial conditions in hybrid inflation

International Nuclear Information System (INIS)

Clesse, Sebastien; Rocher, Jonathan

2009-01-01

Hybrid inflation faces two well-known problems: the blue spectrum of the nonsupersymmetric version of the model and the fine-tuning of the initial conditions of the fields leading to sufficient inflation to account for the standard cosmological problems. They are investigated by studying the exact two-fields dynamics instead of assuming slow-roll. When the field values are restricted to be less than the reduced Planck mass, a non-negligible part of the initial condition space (around 15% depending on potential parameters) leads to successful inflation. Most of it is located outside the usual inflationary valley and organized in continuous patterns instead of being isolated as previously found. Their existence is explained and their properties are studied. This shows that no excessive fine-tuning is required for successful hybrid inflation. Moreover, by extending the initial condition space to Planckian-like or super-Planckian values, inflation becomes generically sufficiently long and can produce a red-tilted scalar power spectrum due to slow-roll violations. The robustness of these properties is confirmed by conducting our analysis on three other models of hybrid-type inflation in various framework: 'smooth' and 'shifted' inflation in SUSY and SUGRA, and 'radion assisted' gauge inflation. A high percentage of successful inflation for smooth hybrid inflation (up to 80%) is observed.

Runaway breakdown and hydrometeors in lightning initiation.

Science.gov (United States)

Gurevich, A V; Karashtin, A N

2013-05-03

The particular electric pulse discharges are observed in thunderclouds during the initiation stage of negative cloud-to-ground lightning. The discharges are quite different from conventional streamers or leaders. A detailed analysis reveals that the shape of the pulses is determined by the runaway breakdown of air in the thundercloud electric field initiated by extensive atmospheric showers (RB-EAS). The high amplitude of the pulse electric current is due to the multiple microdischarges at hydrometeors stimulated and synchronized by the low-energy electrons generated in the RB-EAS process. The series of specific pulse discharges leads to charge reset from hydrometeors to the free ions and creates numerous stretched ion clusters, both positive and negative. As a result, a wide region in the thundercloud with a sufficiently high fractal ion conductivity is formed. The charge transport by ions plays a decisive role in the lightning leader preconditioning.

Initial angular momentum and flow in high energy nuclear collisions

Science.gov (United States)

Fries, Rainer J.; Chen, Guangyao; Somanathan, Sidharth

2018-03-01

We study the transfer of angular momentum in high energy nuclear collisions from the colliding nuclei to the region around midrapidity, using the classical approximation of the color glass condensate (CGC) picture. We find that the angular momentum shortly after the collision (up to times ˜1 /Qs , where Qs is the saturation scale) is carried by the "β -type" flow of the initial classical gluon field, introduced by some of us earlier. βi˜μ1∇iμ2-μ2∇iμ1 (i =1 ,2 ) describes the rapidity-odd transverse energy flow and emerges from Gauss's law for gluon fields. Here μ1 and μ2 are the averaged color charge fluctuation densities in the two nuclei, respectively. Interestingly, strong coupling calculations using anti-de Sitter/conformal field theory (AdS/CFT) techniques also find an energy flow term featuring this particular combination of nuclear densities. In classical CGC the order of magnitude of the initial angular momentum per rapidity in the reaction plane, at a time 1 /Qs , is |d L2/d η |≈ RAQs-3ɛ¯0/2 at midrapidity, where RA is the nuclear radius, and ɛ¯0 is the average initial energy density. This result emerges as a cancellation between a vortex of energy flow in the reaction plane aligned with the total angular momentum, and energy shear flow opposed to it. We discuss in detail the process of matching classical Yang-Mills results to fluid dynamics. We will argue that dissipative corrections should not be discarded to ensure that macroscopic conservation laws, e.g., for angular momentum, hold. Viscous fluid dynamics tends to dissipate the shear flow contribution that carries angular momentum in boost-invariant fluid systems. This leads to small residual angular momentum around midrapidity at late times for collisions at high energies.

Numerical simulations of quiet Sun magnetic fields seeded by the Biermann battery

Science.gov (United States)

Khomenko, E.; Vitas, N.; Collados, M.; de Vicente, A.

2017-08-01

The magnetic fields of the quiet Sun cover at any time more than 90% of its surface and their magnetic energy budget is crucial to explain the thermal structure of the solar atmosphere. One of the possible origins of these fields is the action of the local dynamo in the upper convection zone of the Sun. Existing simulations of the local solar dynamo require an initial seed field and sufficiently high spatial resolution in order to achieve the amplification of the seed field to the observed values in the quiet Sun. Here we report an alternative model of seeding based on the action of the Bierman battery effect. This effect generates a magnetic field due to the local imbalances in electron pressure in the partially ionized solar plasma. We show that the battery effect self-consistently creates from zero an initial seed field of a strength of the order of micro G, and together with dynamo amplification allows the generation of quiet Sun magnetic fields of a similar strength to those from solar observations.

The national geomagnetic initiative

Science.gov (United States)

1993-01-01

The Earth's magnetic field, through its variability over a spectrum of spatial and temporal scales, contains fundamental information on the solid Earth and geospace environment (the latter comprising the atmosphere, ionosphere, and magnetosphere). Integrated studies of the geomagnetic field have the potential to address a wide range of important processes in the deep mantle and core, asthenosphere, lithosphere, oceans, and the solar-terrestrial environment. These studies have direct applications to important societal problems, including resource assessment and exploration, natural hazard mitigation, safe navigation, and the maintenance and survivability of communications and power systems on the ground and in space. Studies of the Earth's magnetic field are supported by a variety of federal and state agencies as well as by private industry. Both basic and applied research is presently supported by several federal agencies, including the National Science Foundation (NSF), U.S. Geological Survey (USGS), U.S. Department of Energy (DOE), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), and U.S. Department of Defense (DOD) (through the Navy, Air Force, and Defense Mapping Agency). Although each agency has a unique, well-defined mission in geomagnetic studies, many areas of interest overlap. For example, NASA, the Navy, and USGS collaborate closely in the development of main field reference models. NASA, NSF, and the Air Force collaborate in space physics. These interagency linkages need to be strengthened. Over the past decade, new opportunities for fundamental advances in geomagnetic research have emerged as a result of three factors: well-posed, first-order scientific questions; increased interrelation of research activities dealing with geomagnetic phenomena; and recent developments in technology. These new opportunities can be exploited through a national geomagnetic initiative to define objectives and

An initial study on atmospheric pressure ion transport by laser ionization and electrostatic fields.

OpenAIRE

Peralta Conde, Álvaro; Romero, Carolina; Boyero, Juan; Apiñaniz Aginako, Jon Imanol; Raposo Funcia, Cesar; Roso Franco, Luis; Padilla Moreno, Carlos Manuel

2014-01-01

Laser ionization of mixtures of gases at atmospheric pressure and the subsequent transport through electrostatic field is studied. A prototype is designed to perform the transport and detection of the ions. Relevance of the composition of the mixture of gases and ionization parameters is shown

Compressions of electrorheological fluids under different initial gap distances.

Science.gov (United States)

Tian, Yu; Wen, Shizhu; Meng, Yonggang

2003-05-01

Compressions of electrorheological (ER) fluids have been carried out under different initial gap distances and different applied voltages. The nominal yield stresses of the compressed ER fluid under different conditions, according to the mechanics of compressing continuous fluids considering the yield stress of the plastic fluid, have been calculated. Curves of nominal yield stress under different applied voltages at an initial gap distance of 4 mm overlapped well and were shown to be proportional to the square of the external electric field and agree well with the traditional description. With the decrease of the initial gap distance, the difference between the nominal yield stress curves increased. The gap distance effect on the compression of ER fluids could not be explained by the traditional description based on the Bingham model and the continuous media theory. An explanation based on the mechanics of particle chain is proposed to describe the gap distance effect on the compression of ER fluids.

Projectile-power-compressed magnetic-field pulse generator

International Nuclear Information System (INIS)

Barlett, R.H.; Takemori, H.T.; Chase, J.B.

1983-01-01

Design considerations and experimental results are presented of a compressed magnetic field pulsed energy source. A 100-mm-diameter, gun-fired projectile of approx. 2MJ kinetic energy was the input energy source. An initial magnetic field was trapped and compressed by the projectile. With a shorted load, a magajoule in a nanohenry was the design goal, i.e., 50 percent energy transformation from kinetic to magnetic. Five percent conversion was the highest recorded before gauge failure

Field Dependence-Field Independence Cognitive Style, Gender, Career Choice and Academic Achievement of Secondary School Students in Emohua Local Government Area of Rivers State

Science.gov (United States)

Onyekuru, Bruno Uchenna

2015-01-01

This is a descriptive study that investigated the relationships among field dependence-field independence cognitive style and gender, career choice and academic achievement of secondary school students in Emohua Local Government Area of Rivers State, Nigeria. From the initial sample of 320 senior secondary school one (SS1) students drawn from the…

The field size matters: low dose external beam radiotherapy for thumb carpometacarpal osteoarthritis : Importance of field size.

Science.gov (United States)

Kaltenborn, Alexander; Bulling, Elke; Nitsche, Mirko; Carl, Ulrich Martin; Hermann, Robert Michael

2016-08-01

The purpose of this work was to evaluate the efficacy of low-dose radiotherapy (RT) for thumb carpometacarpal osteoarthritis (rhizarthrosis). The responses of 84 patients (n = 101 joints) were analyzed 3 months after therapy (n = 65) and at 12 months (n = 27). Patients were treated with 6 fractions of 1 Gy, two times a week, with a linear accelerator. At the end of therapy, about 70 % of patients reported a response (partial remission or complete remission), 3 months later about 60 %, and 1 year after treatment 70 %. In univariate regression analysis, higher patient age and field size greater than 6 × 4 cm were associated with response to treatment, while initial increase of pain under treatment was predictive for treatment failure. Duration of RT series (more than 18 days), gender, time of symptoms before RT, stress pain or rest pain, or prior ortheses use, injections, or surgery of the joint were not associated with treatment efficacy. In multivariate regression analysis, only field size and initial pain increase were highly correlated with treatment outcome. In conclusion, RT represents a useful treatment option for patients suffering from carpometacarpal osteoarthritis. In contrast to other benign indications, a larger field size (>6 × 4 cm) seems to be more effective than smaller fields and should be evaluated in further prospective studies.

Initial results from the Tokapole-II poloidal divertor device

International Nuclear Information System (INIS)

Biddle, A.P.; Dexter, R.N.; Groebner, R.J.; Holly, D.J.; Lipschultz, B.; Phillips, M.W.; Prager, S.C.; Sprott, J.C.

1979-01-01

The latest in a series of internal-ring devices, called Tokapole II, has recently begun operation at the University of Wisconsin. Its purpose is to permit the study of the production and confinement of hot, dense plasmas in either a toroidal octupole (with or without toroidal field) or a tokamak with a four-node poloidal divertor. The characteristics of the device and the results of its initial operation are described here. Quantitative measurements of impurity concentration and radiated power have been made. Poloidal divertor equilibria of square and dee shapes have been produced, and an axisymmetric instability has been observed with the inverse dee. Electron cyclotron resonance heating is used to initiate the breakdown near the axis and to control the initial influx of impurities. A 2-MW RF source at the second harmonic of the ion cyclotron frequency is available and has been used to double the ion temperature when operated at low power with an unoptimized antenna. Initial results of operation as a pure octupole with poloidal Ohmic heating suggest a tokamak-like scaling of density (n proportional to Bsub(p)) and confinement time (tau proportional to n). (author)

Electron dynamics in inhomogeneous magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Nogaret, Alain, E-mail: A.R.Nogaret@bath.ac.u [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom)

2010-06-30

This review explores the dynamics of two-dimensional electrons in magnetic potentials that vary on scales smaller than the mean free path. The physics of microscopically inhomogeneous magnetic fields relates to important fundamental problems in the fractional quantum Hall effect, superconductivity, spintronics and graphene physics and spins out promising applications which will be described here. After introducing the initial work done on electron localization in random magnetic fields, the experimental methods for fabricating magnetic potentials are presented. Drift-diffusion phenomena are then described, which include commensurability oscillations, magnetic channelling, resistance resonance effects and magnetic dots. We then review quantum phenomena in magnetic potentials including magnetic quantum wires, magnetic minibands in superlattices, rectification by snake states, quantum tunnelling and Klein tunnelling. The third part is devoted to spintronics in inhomogeneous magnetic fields. This covers spin filtering by magnetic field gradients and circular magnetic fields, electrically induced spin resonance, spin resonance fluorescence and coherent spin manipulation. (topical review)

Density matrix of a quantum field in a particle-creating background

International Nuclear Information System (INIS)

Gavrilov, S.P.; Gitman, D.M.; Tomazelli, J.L.

2008-01-01

We examine the time evolution of a quantized field in external backgrounds that violate the stability of vacuum (particle-creating backgrounds). Our purpose is to study the exact form of the final quantum state (the density operator at the final instant of time) that has emerged from a given arbitrary initial state (from a given arbitrary density operator at the initial time instant) in the course of evolution. We find a generating functional that allows one to obtain density operators for an arbitrary initial state. Averaging over states of the subsystem of antiparticles (particles), we obtain explicit forms of reduced density operators for the subsystem of particles (antiparticles). Analyzing one-particle correlation functions, we establish a one-to-one correspondence between these functions and the reduced density operators. It is shown that in the general case a presence of bosons (e.g., gluons) in the initial state increases the creation rate of the same type of bosons. We discuss the question (and its relation to the initial stage of quark-gluon plasma formation) whether a thermal form of one-particle distribution can appear even if the final state of the complete system is not in thermal equilibrium. In this respect, we discuss some cases when pair-creation by an electric-like field can mimic the one-particle thermal distribution. We apply our technics to some QFT problems in slowly varying electric-like backgrounds: electric, SU(3) chromoelectric, and metric. In particular, we analyze the time and temperature behavior of the mean numbers of created particles, provided that the effects of switching the external field on and off are negligible. It is demonstrated that at high temperatures and in slowly varying electric fields the rate of particle-creation is essentially time-dependent

Density matrix of a quantum field in a particle-creating background

Energy Technology Data Exchange (ETDEWEB)

Gavrilov, S.P. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05315-970 Sao Paulo, SP (Brazil)], E-mail: gavrilovsergeyp@yahoo.com; Gitman, D.M. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05315-970 Sao Paulo, SP (Brazil)], E-mail: gitman@dfn.if.usp.br; Tomazelli, J.L. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05315-970 Sao Paulo, SP (Brazil)], E-mail: tomazelli@fsc.ufsc.br

2008-06-01

We examine the time evolution of a quantized field in external backgrounds that violate the stability of vacuum (particle-creating backgrounds). Our purpose is to study the exact form of the final quantum state (the density operator at the final instant of time) that has emerged from a given arbitrary initial state (from a given arbitrary density operator at the initial time instant) in the course of evolution. We find a generating functional that allows one to obtain density operators for an arbitrary initial state. Averaging over states of the subsystem of antiparticles (particles), we obtain explicit forms of reduced density operators for the subsystem of particles (antiparticles). Analyzing one-particle correlation functions, we establish a one-to-one correspondence between these functions and the reduced density operators. It is shown that in the general case a presence of bosons (e.g., gluons) in the initial state increases the creation rate of the same type of bosons. We discuss the question (and its relation to the initial stage of quark-gluon plasma formation) whether a thermal form of one-particle distribution can appear even if the final state of the complete system is not in thermal equilibrium. In this respect, we discuss some cases when pair-creation by an electric-like field can mimic the one-particle thermal distribution. We apply our technics to some QFT problems in slowly varying electric-like backgrounds: electric, SU(3) chromoelectric, and metric. In particular, we analyze the time and temperature behavior of the mean numbers of created particles, provided that the effects of switching the external field on and off are negligible. It is demonstrated that at high temperatures and in slowly varying electric fields the rate of particle-creation is essentially time-dependent.

The significance of vector magnetic field measurements

Science.gov (United States)

Hagyard, M. J.

1990-01-01

Observations of four flaring solar active regions, obtained during 1980-1986 with the NASA Marshall vector magnetograph (Hagyard et al., 1982 and 1985), are presented graphically and characterized in detail, with reference to nearly simultaneous Big Bear Solar Observatory and USAF ASW H-alpha images. It is shown that the flares occurred where local photospheric magnetic fields differed most from the potential field, with initial brightening on either side of a magnetic-neutral line near the point of maximum angular shear (rather than that of maximum magnetic-field strength, typically 1 kG or greater). Particular emphasis is placed on the fact that these significant nonpotential features were detected only by measuring all three components of the vector magnetic field.

International Initiatives To Eliminate Corruption: Has Bribery Declined?

OpenAIRE

Claire R. La Roche; Mary A. Flanigan

2011-01-01

Bribery discriminates against honest companies by creating a barrier to entry in the form of a competitive disadvantage. An important legal issue with significant implications is whether recent international anti-corruption laws have leveled the playing field for firms doing business abroad. One of the first laws proscribing illicit payments to foreign public officials is the Foreign Corrupt Practices Act (FCPA), initially enacted by the U.S. Congress in 1977. From its inception, the FCPA has...

Numerical study of the initial dynamics in tormac

International Nuclear Information System (INIS)

Aydemir, A.Y.

1979-01-01

Using a single fluid magnetohydrodynamic (MHD) code, we study the initial plasma dynamics in Tormac, an experimental device which attempts to confine plasma in a toroidal, two-pole cusp field. The code is in two dimensions and includes classical electrical conductivity and a constant heat conductivity. The full set of nonlinear MHD equations for the mass density, fluid velocity, temperature, the poloidal flux function, and the poloidal current function are solved using a predictor-corrector method

Initiation of Solar Eruptions: Recent Observations and Implications for Theories

Science.gov (United States)

Sterling, A. C.

2006-01-01

Solar eruptions involve the violent disruption of a system of magnetic field. Just how the field is destabilized and explodes to produce flares and coronal mass ejections (CMEs) is still being debated in the solar community. Here I discuss recent observational work into these questions by ourselves (me and my colleagues) and others. Our work has concentrated mainly on eruptions that include filaments. We use the filament motion early in the event as a tracer of the motion of the general erupting coronal field in and around the filament, since that field itself is hard to distinguish otherwise. Our main data sources are EUV images from SOHO/EIT and TRACE, soft Xray images from Yohkoh, and magnetograms from SOHO/MDI, supplemented with coronagraph images from SOHO/LASCO, hard X-ray data, and ground-based observations. We consider the observational findings in terms of three proposed eruption-initiation mechanisms: (i) runaway internal tether-cutting reconnection, (ii) slow external tether-cutting reconnection ("breakout"), and (iii) ideal MHD instability.

Evaluating Teachers' Professional Development Initiatives: Towards an Extended Evaluative Framework

Science.gov (United States)

Merchie, Emmelien; Tuytens, Melissa; Devos, Geert; Vanderlinde, Ruben

2018-01-01

Evaluating teachers' professional development initiatives (PDI) is one of the main challenges for the teacher professionalisation field. Although different studies have focused on the effectiveness of PDI, the obtained effects and evaluative methods have been found to be widely divergent. By means of a narrative review, this study provides an…

The dynamics of coupled atom and field assisted by continuous external pumping

International Nuclear Information System (INIS)

Burlak, G.; Hernandez, J.A.; Starostenko, O.

2006-01-01

The dynamics of a coupled system comprising a two-level atom and cavity field assisted by a continuous external classical field (driving Jaynes-Cummings model) is studied. When the initial field is prepared in a coherent state, the dynamics strongly depends on the algebraic sum of both fields. If this sum is zero (the compensative case) in the system, only the vacuum Rabi oscillations occur. The results with dissipation and external field detuning from the cavity field are also discussed. (Author)

The dynamics of coupled atom and field assisted by continuous external pumping

Energy Technology Data Exchange (ETDEWEB)

Burlak, G.; Hernandez, J.A. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma de Morelos, Cuernavaca, Morelos (Mexico); Starostenko, O. [Departamento de Fisica, Electronica, Sistemas y Mecatronica, Universidad de las Americas, 72820 Puebla (Mexico)

2006-07-01

The dynamics of a coupled system comprising a two-level atom and cavity field assisted by a continuous external classical field (driving Jaynes-Cummings model) is studied. When the initial field is prepared in a coherent state, the dynamics strongly depends on the algebraic sum of both fields. If this sum is zero (the compensative case) in the system, only the vacuum Rabi oscillations occur. The results with dissipation and external field detuning from the cavity field are also discussed. (Author)

Optimisation of applied field pulses for microwave assisted magnetic recording

Directory of Open Access Journals (Sweden)

Simon John Greaves

2017-05-01

Full Text Available Grains in a recording medium experience field pulses from a write head during recording. In general, a short head field rise time and a square pulse shape have been viewed as optimal. This work investigates the optimum field pulse shape for microwave assisted magnetic recording on single layer and ECC media. A square pulse was found to give the best recording performance on single layer media, but an initially negative field pulse increasing at a constant rate was more suitable for ECC media.

Innovation technology in the initial training of children by the example of sport games

Directory of Open Access Journals (Sweden)

Ruslana Sushko

2015-04-01

Full Text Available Purpose: to determine the characteristics of innovative technologies and the current state of organizational work with children at the initial stage of training in sports. Material and Methods: to understand the application of innovative technologies used coaches poll and summarized expert assessment specialists in the field of sports. Results: the current state of the question concerning the possibility of the initial training of children in early specialization in sports for example basketball, volleyball and tennis. Clarified the importance and necessity of innovative activities for children at the initial stage of training in sports. Conclusions: the identified innovative approaches for constructing the process of initial training in tennis, which are not observed in other kinds of sports.

Simulation study of effects of initial particle size distribution on dissolution

International Nuclear Information System (INIS)

Wang, G.; Xu, D.S.; Ma, N.; Zhou, N.; Payton, E.J.; Yang, R.; Mills, M.J.; Wang, Y.

2009-01-01

Dissolution kinetics of γ' particles in binary Ni-Al alloys with different initial particle size distributions (PSD) is studied using a three-dimensional (3D) quantitative phase field model. By linking model inputs directly to thermodynamic and atomic mobility databases, microstructural evolution during dissolution is simulated in real time and length scales. The model is first validated against analytical solution for dissolution of a single γ' particle in 1D and numerical solution in 3D before it is applied to investigate the effects of initial PSD on dissolution kinetics. Four different types of PSD, uniform, normal, log-normal and bimodal, are considered. The simulation results show that the volume fraction of γ' particles decreases exponentially with time, while the temporal evolution of average particle size depends strongly on the initial PSD

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field.

Science.gov (United States)

Cadiz, Fabian; Djeffal, Abdelhak; Lagarde, Delphine; Balocchi, Andrea; Tao, Bingshan; Xu, Bo; Liang, Shiheng; Stoffel, Mathieu; Devaux, Xavier; Jaffres, Henri; George, Jean-Marie; Hehn, Michel; Mangin, Stephane; Carrere, Helene; Marie, Xavier; Amand, Thierry; Han, Xiufeng; Wang, Zhanguo; Urbaszek, Bernhard; Lu, Yuan; Renucci, Pierre

2018-04-11

The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to 35% at zero applied magnetic field. The injection of spin-polarized electrons is achieved by combining ultrathin CoFeB electrodes on top of a spin-LED device with p-type InGaAs quantum dots in the active region. We measure an Overhauser shift of several microelectronvolts at zero magnetic field for the positively charged exciton (trion X + ) EL emission, which changes sign as we reverse the injected electron spin orientation. This is a signature of dynamic polarization of the nuclear spins in the quantum dot induced by the hyperfine interaction with the electrically injected electron spin. This study paves the way for electrical control of nuclear spin polarization in a single quantum dot without any external magnetic field.

The North Field Development

International Nuclear Information System (INIS)

1993-01-01

The Qatar Europe LNG Company's activities include gas production, gathering, treatment, liquefaction, shipping and marketing of Liquefied Natural Gas (LNG) and by-products. The (LNG) project to be developed by the Company shall be initially capable of processing 1200 mmscfd of raw gas and associated quantities of condensate from the North Field. Hydrocarbons produced will be delivered to shore in the industrial area (Ras Laffan) via a sub sea pipeline system. Raw gas is used as a feedstock into the liquefaction plant which is initially capable of producing 6.1 Million Tonnes Per Annum (MTPA) of (LNG). The initial quantity of (LNG) will be exported from (Ras Laffan) loading terminal to a receiving terminal located on the North East coast of Italy via a dedicated fleet of (LNG) carriers. The whole project (Upstream, Downstream and Shipping) shall be executed on an integrated scheme basis under the the direct control of the Qatar Europe LNG Company and in accordance with the overall Master Schedule in order to ensure a delivery of first shipment of (LNG) in the 2 nd half of 1997. 3 figs

Biotropic parameters of magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Shishlo, M.A.

The use of magnetic fields (MF) in biology and medicine to control biological systems has led to appearance of the term, biotropic parameters of MF. They include the physical characteristics of MF, which determine the primary biologically significant physicochemical mechanisms of field action causing formation of corresponding reactions on the level of the integral organism. These parameters include MF intensity, gradient, vector, pulse frequency and shape, and duration of exposure. Factors that elicit responses by the biological system include such parameter of MF interaction with the integral organism as localization of exposure and volume of tissues interacting with the field, as well as the initial state of the organism. In essence, the findings of experimental studies of biotropic parameters of MF make it possible to control physiological processes and will aid in optimizing methods of MF therapy.

Primordial black holes as seeds of magnetic fields in the universe

Science.gov (United States)

Safarzadeh, Mohammadtaher

2018-06-01

Although it is assumed that magnetic fields in accretion disks are dragged from the interstellar medium, the idea is likely not applicable to primordial black holes (PBHs) formed in the early universe. Here we show that magnetic fields can be generated in initially unmagnetized accretion disks around PBHs through the Biermann battery mechanism, and therefore provide the small scale seeds of magnetic field in the universe. The radial temperature and vertical density profiles of these disks provide the necessary conditions for the battery to operate naturally. The generated seed fields have a toroidal structure with opposite sign in the upper and lower half of the disk. In the case of a thin accretion disk around a rotating PBH, the field generation rate increases with increasing PBH spin. At a fixed r/risco, where r is the radial distance from the PBH and risco is the radius of the innermost stable circular orbit, the battery scales as M-9/4, where M is the PBH's mass. The very weak dependency of the battery on accretion rate, makes this mechanism a viable candidate to provide seed fields in an initially unmagnetized accretion disk, following which the magnetorotational instability could take over.

Modelling vacuum arcs : from plasma initiation to surface interactions

International Nuclear Information System (INIS)

Timko, H.

2011-01-01

A better understanding of vacuum arcs is desirable in many of today's 'big science' projects including linear colliders, fusion devices, and satellite systems. For the Compact Linear Collider (CLIC) design, radio-frequency (RF) breakdowns occurring in accelerating cavities influence efficiency optimisation and cost reduction issues. Studying vacuum arcs both theoretically as well as experimentally under well-defined and reproducible direct-current (DC) conditions is the first step towards exploring RF breakdowns. In this thesis, we have studied Cu DC vacuum arcs with a combination of experiments, a particle-in-cell (PIC) model of the arc plasma, and molecular dynamics (MD) simulations of the subsequent surface damaging mechanism. We have also developed the 2D Arc-PIC code and the physics model incorporated in it, especially for the purpose of modelling the plasma initiation in vacuum arcs. Assuming the presence of a field emitter at the cathode initially, we have identified the conditions for plasma formation and have studied the transitions from field emission stage to a fully developed arc. The 'footing' of the plasma is the cathode spot that supplies the arc continuously with particles; the high-density core of the plasma is located above this cathode spot. Our results have shown that once an arc plasma is initiated, and as long as energy is available, the arc is self-maintaining due to the plasma sheath that ensures enhanced field emission and sputtering.The plasma model can already give an estimate on how the time-to-breakdown changes with the neutral evaporation rate, which is yet to be determined by atomistic simulations. Due to the non-linearity of the problem, we have also performed a code-to-code comparison. The reproducibility of plasma behaviour and time-to-breakdown with independent codes increased confidence in the results presented here. Our MD simulations identified high-flux, high-energy ion bombardment as a possible mechanism forming the early

Irrigation initiation timing in soybean grown on sandy soils in Northeast Arkansas

Science.gov (United States)

Irrigation initiation timing was evaluated in furrow-irrigated soybean field with sandy soils in Mississippi County, AR. A major objective of this 2015 study was to validate and expand irrigation timing recommendations that pair plant growth measures with weather cues including use of local weather ...

Second quantization of classical nonlinear relativistic field theory. Pt. 2

International Nuclear Information System (INIS)

Balaban, T.

1976-01-01

The construction of a relativistic interacting local quantum field is given in two steps: first the classical nonlinear relativistic field theory is written down in terms of Poisson brackets, with initial conditions as canonical variables: next a representation of Poisson bracket Lie algebra by means of linear operators in the topological vector space is given and an explicit form of a local interacting relativistic quantum field PHI is obtained. (orig./BJ) [de

The CRINE initiative -- Education and training

International Nuclear Information System (INIS)

Littlewood, S.K.

1995-01-01

CRINE's aim is to have everyone in the industry working in new ways and doing so because it is second nature. CRINE is an acronym for Cost Reduction Initiative for the New Era, is an industry-wide program now under way in the UK continental shelf oil and gas fields whose main objective is to achieve thirty percent or more savings in capital costs and to half the operating costs over the next few years. Such a culture change is only feasible through an extensive program of education and training. This is under way, helped in many organizations by CRINE 'champions' driving the courses and training aids

Stabilization and destabilization effects of the electric field on stochastic precipitate pattern

NARCIS (Netherlands)

Lagzi, István; Izsak, F.

2004-01-01

Stabilization and destabilization effects of an applied electric field on the Liesegang pattern formation in low concentration gradient were studied with numerical model simulations. In the absence of an electric field pattern formation exhibits increasingly stochastic behaviour as the initial

Initial stage of cavitation in liquids and its observation by Rayleigh scattering

Energy Technology Data Exchange (ETDEWEB)

Pekker, M [Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052, United States of America (United States); Shneider, M N, E-mail: m.n.shneider@gmail.com [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, United States of America (United States)

2017-06-15

A theory is developed for the initial stage of cavitation in the framework of Zel’dovich–Fisher theory of nucleation in the field of negative pressure, while taking into account the surface tension dependence on the nanopore radius. A saturation mechanism is proposed that limits the exponential dependence of the nucleation rate on the energy required to create nanopores. An estimate of the saturated density of nanopores at the nucleation stage is obtained. It is shown that Rayleigh scattering can detect nanopores arising at the initial stage of cavitation development. (paper)

On the initial conditions for a universe with variable G and c

International Nuclear Information System (INIS)

Gomide, F.M.; Uehara, M.

1978-01-01

Initial conditions are discussed for a closed universe with matter injection process and with time varying G and c. It is shown that the usual interpretation for the cosmic microwave background radiation can be accepted for this model universe, provided a certain initial condition is imposed on the Pryce-Hoyle field. The time varying c is responsible for two red-shift laws one for wave-length and the other for the frequency. If radiation temperature obeys the red-shift law for frequency, the primordial Planck spectrum can be reproduced along cosmic expansion [pt

New approach to the problem of gauge field quantization

International Nuclear Information System (INIS)

Skachkov, N.B.; Shevchenko, O.Yu.

1987-01-01

A new scheme of calibration field quantization containing considerable change of the procedure of calibration conditions application on field variables is suggested. The above approach is based on a proved theorem on the subordination of fields to the additional Lorenz condition when applying a wide class of initial calibration conditions on these fields. This condition has the sense of the secondary bond, which must be included in the system of bonds during field quantization. The fact of secondary bond presence in the form of Lorenz condition was not earlier considered in literature and used in quantization. Due to this, the report suggests modification of all existing methods of field quantization: according to Dirac-Bergman, covariant approach using an indefinite metric and the method of functional integration

The evolution of helical cosmic magnetic fields as predicted by MHD closure theory

Energy Technology Data Exchange (ETDEWEB)

Saveliev, Andrey; Sigl, Guenter [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Jedamzik, Kartsen [Univ. Montpellier-2. (France). Laboratoire Univers et Particules de Montpellier

2013-04-15

We extend our recent derivation of the time evolution equations for the energy content of magnetic fields and turbulent motions for incompressible, homogeneous, and isotropic turbulence to include the case of non-vanishing helicity. These equations are subsequently numerically integrated in order to predict the present day primordial magnetic field strength and correlation length, depending on its initial helicity and magnetic energy density. We find that all prior analytic predictions for helical magnetic fields, such as the epoch when they become maximally helical and their subsequent growth of correlation length L {proportional_to} a{sup 1/3} and decrease of magnetic field strength B {proportional_to} a{sup -1/3} with scale factor a are well confirmed by the simulations. An initially fully helical primordial magnetic field is a factor 4 x 10{sup 4} stronger at the present epoch then its non-helical counterpart when generated during the electroweak epoch.

Numerical simulation of positive streamer development in thundercloud field enhanced near raindrops

DEFF Research Database (Denmark)

Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

2016-01-01

As the threshold field strength for the breakdown in air significantly exceeds the maximum measured thundercloud strength 3 kV/cm/atm, the problem of lightning initiation remains unclear. According to the popular idea, lightning can be initiated from streamer discharges developed in the enhanced...

Ionization and recombination in attosecond electric field pulses

International Nuclear Information System (INIS)

Dimitrovski, Darko; Solov'ev, Eugene A.; Briggs, John S.

2005-01-01

Based on the results of a previous communication [Dimitrovski et al., Phys. Rev. Lett. 93, 083003 (2004)], we study ionization and excitation of a hydrogenic atom from the ground and first excited states in short electric field pulses of several cycles. A process of ionization and recombination which occurs periodically in time is identified, for both small and extremely large peak electric field strengths. In the limit of large electric peak fields closed-form analytic expressions for the population of the initial state after single- and few-cycle pulses are derived. These formulas, strictly valid for asymptotically large momentum transfer from the field, give excellent agreement with fully numerical calculations for all momentum transfers

Ambiguities on electric and magnetic fields for an extended gauge model

International Nuclear Information System (INIS)

Colatto, L.P.; Doria, R.M.

1990-01-01

Generalized electric and magnetic fields in a system containing N-potential fields in the same U (1) - group are obtained. Bianchi identities, equations of motions, conserved charges and Lorentz forces are developed in association to each of these fields. Such facts confirm that the same parameter α (x) is able to organize the presence of distinct fields. The physics generated from the minimal action principle is independent of the initial definition for the electric (magnetic) field. Nevertheless, such a choice reveals differences in the Bianchi identity context. (author)

Oil and gas field development: an NOC perspective

Energy Technology Data Exchange (ETDEWEB)

Kronman, George [Halliburton Energy Services (United States). Landmark Division

2004-07-01

Every day, oil companies around the world face real-life field development and management problems like the ones described above. Making timely and well-informed field development decisions are among the most important decisions the management of any oil company can make. The field development phase of the oil and gas life cycle extends from the discovery of a hydrocarbon deposit through initial production. It also includes revitalization of mature and marginal fields. Field development projects require the greatest level of cross-disciplinary integration and the largest investment decisions in the entire oil field life cycle. The ultimate economic success or failure of most fields is set by the quality of decisions made during field development. Oil companies take many different approaches to field development based on unique business drivers, their asset portfolio mix and risk tolerance, access to data and experienced manpower, adoption of technology, availability of capital, ownership, management style and so on. This paper focuses on understanding and addressing the particular field development challenges facing NOCs today. (author)

Initial operation of a high-power quasi-optical gyrotron

International Nuclear Information System (INIS)

Fliflet, A.W.; Hargreaves, T.A.; Manheimer, W.M.; Fischer, R.P.; Barsanti, M.L.

1990-01-01

Results from the initial operating of a high-power quasi-optical gyrotron based on the 90-kV 50-A Varian VUW-8144 electron gun are reported. The output power and efficiency have been measured for a resonator mirror separation of 19.4 cm with a magnetic field of 4.95 T, corresponding to resonator output coupling of 1.9%, and for a resonator mirror separation of 21.4 cm with a magnetic field of 4.7 T, corresponding to a resonator output coupling of 3.1%. Operation was multimoded with 3--6 modes excited in the range of 125--130 GHz for the 4.95-T magnetic field. A peak efficiency of 15% at an output power of 161 kW was obtained for a gun voltage of 93 kV and a current of 12 A. A peak-output power of 364 kW at an efficiency of 10% was obtained at a voltage of 95.6 kV and 37.5 A

Developing agricultural opportunities on mine tailings : the Green Mines green energy initiative