WorldWideScience

Sample records for berkelium 252

  1. New berkelium isotope: 242Bk

    International Nuclear Information System (INIS)

    A new isotope of berkelium, 242Bk, was produced with a cross section of approx. 10 μb in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7 +- 1.3 minutes. The branching ratio for this isotope for alpha decay is less than 1% and that for spontaneous fission is less than 0.03%. 2 figures, 2 tables

  2. Characterization of berkelium(III) dipicolinate and borate compounds in solution and the solid state.

    Science.gov (United States)

    Silver, Mark A; Cary, Samantha K; Johnson, Jason A; Baumbach, Ryan E; Arico, Alexandra A; Luckey, Morgan; Urban, Matthew; Wang, Jamie C; Polinski, Matthew J; Chemey, Alexander; Liu, Guokui; Chen, Kuan-Wen; Van Cleve, Shelley M; Marsh, Matthew L; Eaton, Teresa M; van de Burgt, Lambertus J; Gray, Ashley L; Hobart, David E; Hanson, Kenneth; Maron, Laurent; Gendron, Frédéric; Autschbach, Jochen; Speldrich, Manfred; Kögerler, Paul; Yang, Ping; Braley, Jenifer; Albrecht-Schmitt, Thomas E

    2016-08-26

    Berkelium is positioned at a crucial location in the actinide series between the inherently stable half-filled 5f(7) configuration of curium and the abrupt transition in chemical behavior created by the onset of a metastable divalent state that starts at californium. However, the mere 320-day half-life of berkelium's only available isotope, (249)Bk, has hindered in-depth studies of the element's coordination chemistry. Herein, we report the synthesis and detailed solid-state and solution-phase characterization of a berkelium coordination complex, Bk(III)tris(dipicolinate), as well as a chemically distinct Bk(III) borate material for comparison. We demonstrate that berkelium's complexation is analogous to that of californium. However, from a range of spectroscopic techniques and quantum mechanical calculations, it is clear that spin-orbit coupling contributes significantly to berkelium's multiconfigurational ground state. PMID:27563098

  3. Californium-252 neutron sources

    International Nuclear Information System (INIS)

    Major production programs for the Savannah River reactors and the High Flux Isotopes Reactor at Oak Ridge have made 252Cf one of the most available and, at the USAEC's sales price of $10/μg, one of the least-expensive isotopic neutron sources. Reactor production has totaled approximately 2 g, and, based on expected demand, an additional 10 g will be produced in the next decade. The approximately 800 mg chemically separated to date has been used to prepare over 600 neutron sources. Most, about 500, have been medical sources containing 1 to 5 μg of 252Cf plated in needles for experimental cancer therapy studies. The remainder have generally been point sources containing 10 μg to 12 mg of oxide for activation, well logging, or radiography uses. Bulk sources have also been supplied to the commercial encapsulators. The latest development has been the production of 252Cf cermet wire which can be cut into almost contamination-free lengths of the desired 252Cf content. Casks are available for transport of sources up to 50 mg. Subcritical assemblies have been developed to multiply the source neutrons by a factor of 10 to 40, and collimators and thermalizers have also been extensively developed to shape the neutron flux and energy distributions for special applications. (U.S.)

  4. Oxidation-reduction properties of americium, curium, berkelium, californium, einsteinium and fermium, and thermodynamic consequences for the 5f series

    International Nuclear Information System (INIS)

    The amalgamation of 5f elements from Am to Fm has been studied by using 241Am, 244Cm, 249Bk, 249Cf, 252Cf, 253Es, 254Es, 252Fm and 255Fm with two electrochemical methods, radiocoulometry and radiopolarography, perfectly adapted to investigate extremely diluted solutions when the concentration of electroactive species is as low as 10-16M. The theory of radiocoulometry has been developed in the general cases of reversible and irreversible electrode process. It has been used to interpret the experimental data on the kinetic curves of amalgamation, and to estimate the standard rate constant of the electrode process in complexing medium (citric). On the other hand the radiopolarographic method has been applied to study the mechanism of reduction at the dropping mercury electrode of cations M3+ in aqueous medium to the metal M with formation of amalgam. The results are exploited into two directions: 1- Acquisition of some data concerning the oxidation-reduction properties of elements from Am to Fm. Therefore the standard electrode E0 [M(III-0)] potentials for Bk, Cf and Es, and the standard electrode E0 [M(II-0)] potential for Fm are estimated and the relative stability of each oxidation state (from II to VII) of 5f elements is discussed; 2- Acquisition of unknown thermodynamic data on transcalifornium elements. Correlations between 4f and 5f elements are precised and some divergences appear for the second half of 4f and 5f series (i.e. for 65<=Z<=71 and 97<=Z<=103)

  5. Quantitative determination of 252Cf

    International Nuclear Information System (INIS)

    Sealed 252Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. The authors propose to use gamma-ray spectroscopy for such analysis. In particular, high-energy gamma rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. They have measured the gamma/alpha ratio for 252Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin 252Cf sources, alpha pulse height analysis, determination of alpha decay rate, and the measurement of gamma singles spectrum with a well shielded germanium spectrometer. The measured ratio and the gamma ray spectroscopy of unknown samples can provide the activity of 252Cf in these samples

  6. Quantitative determination of 252Cf

    International Nuclear Information System (INIS)

    Sealed 252Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. We propose to use γ-ray spectroscopy for such analysis. In particular, high-energy γ rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. It is found that the 1435.8-keV γ-ray of 138Cs and the 1596.5-keV γ-ray of 140La are well isolated and sufficiently above the background under these peaks. We have measured the γ/α ratio for the 252Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin 252Cf sources, alpha pulse height analysis, determination of α decay rate, and the measurement of γ singles spectrum with a well-shielded germanium spectrometer. The measured ratio and the γ-ray spectroscopy of unknown samples can provide the activity of 252Cf in these samples

  7. 14 CFR 252.13 - Small aircraft.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Small aircraft. 252.13 Section 252.13 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.13 Small aircraft. Air carriers shall prohibit smoking on...

  8. 15 CFR 25.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Definitions. 25.2 Section 25.2 Commerce and Foreign Trade Office of the Secretary of Commerce PROGRAM Fraud Civil Remedies § 25.2 Definitions. ALJ means an Administrative Law Judge in the authority appointed pursuant to 5 U.S.C. 3105...

  9. Graphite moderated (252)Cf source.

    Science.gov (United States)

    Sajo-Bohus, Laszlo; Barros, Haydn; Greaves, Eduardo D; Vega-Carrillo, Hector Rene

    2015-06-01

    The Thorium molten-salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid-fuel reactor. The neutron source to run this subcritical reactor is a (252)Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the (252)Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. PMID:25770393

  10. Graphite moderated 252Cf source

    International Nuclear Information System (INIS)

    The thorium molten salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid fuel reactor. The neutron source to run this subcritical reactor is a 252Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the 252Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. (Author)

  11. Radionuclide 252Cf neutron source

    International Nuclear Information System (INIS)

    Characteristics of radionuclide neutron sourses of 252Cf base with the activity from 106 to 109 n/s have been investigated. Energetic distributions of neutrons and gamma-radiation have been presented. The results obtained have been compared with other data available. The hardness parameter of the neutron spectrum for the energy range from 3 to 15 MeV is 1.4 +- 0.02 MeV

  12. 7 CFR 3565.252 - Housing types.

    Science.gov (United States)

    2010-01-01

    ... housing must meet Agency requirements contained in 7 CFR part 1924, subpart A or a successor regulation... 7 Agriculture 15 2010-01-01 2010-01-01 false Housing types. 3565.252 Section 3565.252 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF...

  13. 46 CFR 252.13 - Contract.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Contract. 252.13 Section 252.13 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS AFFECTING SUBSIDIZED VESSELS AND OPERATORS OPERATING... Contract. Upon approval by the Board of an application for ODS, the applicant and the United States...

  14. 24 CFR 221.252 - Substitute mortgagors.

    Science.gov (United States)

    2010-04-01

    ... Cost Homes § 221.252 Substitute mortgagors. (a) Selling mortgagor. The mortgagee may effect the release... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 221.252... approval of a substitute mortgagor, as provided by this section. (b) Purchasing mortgagor. The...

  15. 14 CFR 252.9 - Ventilation systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC... as to provide the level and quality of ventilation specified and designed by the manufacturer for...

  16. 40 CFR 265.252 - Waste analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Waste analysis. 265.252 Section 265... FACILITIES Waste Piles § 265.252 Waste analysis. In addition to the waste analyses required by § 265.13, the... in the pile to which it is to be added. The analysis conducted must be capable of...

  17. Dicty_cDB: AFM252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AF (Link to library) AFM252 (Link to dictyBase) - - - - AFM252P (Link to Original site) AFM252F 544 AFM...252Z 683 AFM252P 1207 - - Show AFM252 Library AF (Link to library) Clone ID AFM252 (Link... to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/AF/AFM...2-C/AFM252Q.Seq.d/ Representative seq. ID AFM252P (Link to... Original site) Representative DNA sequence >AFM252 (AFM252Q) /CSM/AF/AFM2-C/AFM252Q.Seq.d/ AAAAAAATGCAAGATA

  18. Dicty_cDB: VHD252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VH (Link to library) VHD252 (Link to dictyBase) - - - Contig-U16379-1 VHD252P (Link to Original site) VHD2...52F 596 VHD252Z 740 VHD252P 1316 - - Show VHD252 Library VH (Link to library) Clone ID VHD2...e URL http://dictycdb.biol.tsukuba.ac.jp/CSM/VH/VHD2-C/VHD252Q.Seq.d/ Representative seq. ID VHD2...52P (Link to Original site) Representative DNA sequence >VHD252 (VHD252Q) /CSM/VH/VHD2-C/VHD2...KIYQ Homology vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value VHD252 (VHD252Q) /CSM/VH/VHD2-C/VHD2

  19. Californium-252: a remarkable versatile radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Osborne-Lee, I.W.; Alexander, C.W.

    1995-10-10

    A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

  20. Californium-252: a remarkable versatile radioisotope

    International Nuclear Information System (INIS)

    A product of the nuclear age, Californium-252 (252Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, 252Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of 252Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the 252Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, 252Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of 252Cf from ORNL is summarized herein

  1. 14 CFR 252.8 - Extent of smoking restrictions.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Extent of smoking restrictions. 252.8... PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.8 Extent of smoking restrictions. The restrictions on smoking described in §§ 252.3 through 252.7 shall apply to all locations within the aircraft....

  2. Californium-252 progress, report No. 7, April 1971

    Energy Technology Data Exchange (ETDEWEB)

    1971-12-31

    This report contains discusses of the following topics on Californium-252: First sales of californium-252; encapsulation services discussed; three new participants in market evaluation program; summer training programs to use californium; Californium-252 shipping casks available; Californium-252 questions and answers, radiotherapy; neutron radiography; natural resources exploration; nuclear safeguards; process control; dosimetry; neutron radiography; neutron shielding; and nuclear safeguards.

  3. Xe-135 Production from Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    C. A. McGrath; T. P. Houghton; J. K. Pfeiffer; R. K. Hague

    2012-03-01

    135Xe is a good indicator that fission has occurred and is a valuable isotope that helps enforce the Comprehensive Test Ban Treaty. Due to its rather short half life and minimal commercial interest, there are no known sources where 135Xe can be purchased. Readily available standards of this isotope for calibrating collection and analytical techniques would be very useful. 135Xe can be produced in the fissioning of actinide isotopes, or by neutron capture on 134Xe. Since the neutron capture cross section of 134Xe is 3 mB, neutron capture is a low yield, though potentially useful, production route. 135Xe is also produced by spontaneous fission of 252Cf. 252Cf has a spontaneous fission rate of about 6 x 1011 s-1g-1. The cumulative yield from the spontaneous fission of 252Cf is 4.19%; and the competing neutron capture reaction that depletes 135Xe in thermal reactor systems is negligible because the neutron capture cross-section is low for fast fission neutrons. At the INL, scientists have previously transported fission products from an electroplated 252Cf thin source for the measurement of nuclear data of short-lived fission products using a technique called He-Jet collection. We have applied a similar system to the collection of gaseous 135Xe, in order to produce valuable standards of this isotope.

  4. 29 CFR 1910.252 - General requirements.

    Science.gov (United States)

    2010-07-01

    ... atmospheres penetrated by the ultraviolet radiation of gas-shielded welding operations. (12) Cutting of... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.252 General requirements. (a) Fire... contractors) and those in management on whose property cutting and welding is to be performed, see...

  5. 27 CFR 25.252 - Records.

    Science.gov (United States)

    2010-04-01

    ... TREASURY LIQUORS BEER Removal of Brewer's Yeast and Other Articles § 25.252 Records. (a) Production. The brewer shall keep records of the production of malt syrup, wort, and other articles which are removed... of brewer's yeast, malt and other articles from the brewery. The record shall include the...

  6. 18 CFR 25.2 - Hearings.

    Science.gov (United States)

    2010-04-01

    ... 25.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT APPLICATION FOR VACATION OF WITHDRAWAL AND FOR... determination: (a) That where lands of the United States have heretofore been, or hereafter may be, reserved...

  7. 252Cf encapsulation and shipping at SRL

    International Nuclear Information System (INIS)

    Techniques were developed at the Savannah River Laboratory to encapsulate 252Cf sources for research and for medical and industrial applications. The sources are for sale or loan under the USAEC market evaluation program. A new facility is described which limits radiation exposure rates to less than mrem/h in normally occupied areas, except for short periods when maximum amounts of up to 100 mg of 252Cf may be handled. Sources as large as 10 mg have been made in this facility. The entire complex is surrounded by up to 48 in. of gamma and neutron shielding. Equipment was designed for remote handling, assembly, and examination of microliter quantities of solutions and capsule components as small as 1/8-in. cylinders. Special equipment, procedures, and carriers are described for safe, practical handling, storage, and shipment of encapsulated 252Cf. Brief descriptions and photographs of six casks most commonly used for transporting quantities ranging from 100 μg to 50 mg of 252Cf are included. (U.S.)

  8. 14 CFR 252.7 - No-smoking sections.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false No-smoking sections. 252.7 Section 252.7... REGULATIONS SMOKING ABOARD AIRCRAFT § 252.7 No-smoking sections. (a) Except as provided in paragraph (b) of... shall provide, at a minimum: (1) A no-smoking section for each class of service; (2) A sufficient...

  9. 27 CFR 41.252 - Change in ownership or control.

    Science.gov (United States)

    2010-04-01

    ... control. 41.252 Section 41.252 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... § 41.252 Change in ownership or control. (a) Fiduciary successor. If an administrator, executor... any occurrence that results in a person acquiring ownership or control of more than ten percent...

  10. Historical review of californium-252 discovery and development

    International Nuclear Information System (INIS)

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving 252Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed

  11. 48 CFR 252.246-7002 - Warranty of construction (Germany).

    Science.gov (United States)

    2010-10-01

    ... (Germany). 252.246-7002 Section 252.246-7002 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.246-7002 Warranty of construction (Germany). As prescribed in 246.710(4), use the following clause: Warranty of Construction (Germany) (JUN 1997) (a) In addition to any...

  12. 48 CFR 252.217-7004 - Job orders and compensation.

    Science.gov (United States)

    2010-10-01

    ... compensation. 252.217-7004 Section 252.217-7004 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.217-7004 Job orders and compensation. As prescribed in 217.7104(a), use the following clause: JOB ORDERS AND COMPENSATION (MAY 2006) (a) The Contracting Officer shall...

  13. 48 CFR 252.211-7003 - Item identification and valuation.

    Science.gov (United States)

    2010-10-01

    ... valuation. 252.211-7003 Section 252.211-7003 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.211-7003 Item identification and valuation. As prescribed in 211.274-6(a), use the following clause: Item Identification and Valuation (AUG 2008) (a) Definitions. As...

  14. 46 CFR 252.33 - Hull and machinery insurance.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Hull and machinery insurance. 252.33 Section 252.33... Subsidy Rates § 252.33 Hull and machinery insurance. (a) Subsidy items. The fair and reasonable net premium costs (including stamp taxes) of hull and machinery, increased value, excess general...

  15. 40 CFR 180.252 - Tetrachlorvinphos; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... residues. 180.252 Section 180.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.252 Tetrachlorvinphos; tolerances for residues. (a) General. Tolerances are established for...

  16. Graphite moderated {sup 252}Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Sajo B, L.; Barros, H.; Greaves, E. D. [Universidad Simon Bolivar, Nuclear Physics Laboratory, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of); Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    The thorium molten salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid fuel reactor. The neutron source to run this subcritical reactor is a {sup 252}Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the {sup 252}Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. (Author)

  17. Material recognition with a 252Cf source

    CERN Document Server

    Fabris, Daniela; Lunardon, Marcello; Moretto, Sandra; Nebbia, Giancarlo; Pesente, Silvia; Stevanato , Luca; Viesti, Giuseppe; Sajo-Bohusb, Laszlo

    2010-01-01

    Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged 252Cf source. Light elements (C,N,O) are identified by using the measured transmission versus neutron time of flight. The yield of the transmitted gamma ray as a function of energy provides high precision identification of the atomic number of the sample up to Z=83 . A tomography system, currently under construction, is described.

  18. Californium-252 Neutron Therapy in China

    International Nuclear Information System (INIS)

    Californium-252 brachytherapy, believed to be the most successful source for neutron therapy, gives most of the cures as well as long-term and complication-free survivals. Chinese radiation oncologists were interested in californium neutron therapy (Cf-NT) in the early 1980s, but 252Cf sources for medical use were not available in China until 1992 when a californium joint venture was established by the China Institute of Atomic Energy (Beijing) and the Research Institute for Nuclear Reactors (Dimitrovgrad) of Russia. In 1995, 25 seeds of 252Cf with a strength of 3 μg each were sent to China for preclinical investigation. Three years later, a high dose rate (HDR) 252Cf source was imported and transferred into a home-made remote after-loader for intracavitary treatment in Chongqing, and a clinical trail was started in February 1999. This is the first time that Cf-NT was performed for cancer patients in China. Since then, Cf-NT in China has developed rapidly. It is estimated that one-tenth of those radiation oncology centers with brachytherapy practice will be equipped with californium units in 5 yr. That means more than 30 units will be in use in hospitals. That is significant compared with other countries, but it is just one, on average, for each province or one per 40 million people in China. Progress also has been achieved in the 252Cf treatment delivery equipment. Preliminary clinical trails showed complete response observed in all cases treated, with a rapid clearance of tumors and mild reactions in normal tissues. The short-term results are quite encouraging. To deal with problems due to the demand for Cf-NT in China, attention should be paid to the following particulars: (1) A high-strength miniature source is needed for HDR/MDR interstitial therapy to extend the Cf-NT coverage. (2) Basic work on radiophysics and radiobiology needs to be done, including source calibration, clinical dosimetry, clinical RBE determination, and Cf-NT quality assurance

  19. 48 CFR 252.236-7005 - Airfield safety precautions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Airfield safety precautions. 252.236-7005 Section 252.236-7005 Federal Acquisition Regulations System DEFENSE ACQUISITION... to contract performance might result in vertical projections at or above the...

  20. 48 CFR 252.228-7001 - Ground and flight risk.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Ground and flight risk. 252.228-7001 Section 252.228-7001 Federal Acquisition Regulations System DEFENSE ACQUISITION...) Conventional winged aircraft, as well as helicopters, vertical take-off or landing aircraft,...

  1. 48 CFR 252.229-7001 - Tax relief.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Tax relief. 252.229-7001... Clauses 252.229-7001 Tax relief. As prescribed in 229.402-70(a), use the following clause: Tax Relief (JUN 1997) (a) Prices set forth in this contract are exclusive of all taxes and duties from which the...

  2. 48 CFR 252.232-7000 - Advance payment pool.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Advance payment pool. 252... Provisions And Clauses 252.232-7000 Advance payment pool. As prescribed in 232.412-70(a), use the following clause: Advance Payment Pool (DEC 1991) (a) Notwithstanding any other provision of this contract,...

  3. Historical Review of Californium-252 Discovery and Development

    Science.gov (United States)

    Stoddard, D. H.

    1985-01-01

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed. (PLG)

  4. 43 CFR 2.52 - Conduct of employees.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Conduct of employees. 2.52 Section 2.52 Public Lands: Interior Office of the Secretary of the Interior RECORDS AND TESTIMONY; FREEDOM OF... employee of the Department may disclose records subject to the Privacy Act unless disclosure is...

  5. 14 CFR 252.3 - Smoking ban: air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Smoking ban: air carriers. 252.3 Section... PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.3 Smoking ban: air carriers. Air carriers shall prohibit smoking on all scheduled passenger flights....

  6. 14 CFR 252.5 - Smoking ban: foreign air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Smoking ban: foreign air carriers. 252.5... PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.5 Smoking ban: foreign air carriers. (a) Foreign air carriers shall prohibit smoking on all scheduled passenger flight segments: (1) Between...

  7. 48 CFR 252.237-7017 - Individual laundry.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Individual laundry. 252... Provisions And Clauses 252.237-7017 Individual laundry. As prescribed in 237.7101(f), use the following clause: Individual Laundry (DEC 1991) (a) The Contractor shall provide laundry service under...

  8. 48 CFR 252.217-7015 - Safety and health.

    Science.gov (United States)

    2010-10-01

    ... U.S.C. 651, et seq.); (b) The Safety and Health Regulations for Ship Repairing (29 CFR part 1915... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Safety and health. 252.217... Clauses 252.217-7015 Safety and health. As prescribed in 217.7104(a), use the following clause: Safety...

  9. 7 CFR 765.252 - Lease of security.

    Science.gov (United States)

    2010-01-01

    ... subpart G of 7 CFR part 1940. (c) Lease of chattel security. Lease of chattel security is not authorized... 7 Agriculture 7 2010-01-01 2010-01-01 false Lease of security. 765.252 Section 765.252 Agriculture... Lease of security. (a) Real estate leases. The borrower may lease real estate security provided...

  10. The U.S. Department of Energy 252Cf program

    International Nuclear Information System (INIS)

    Soon after the discovery of the 252Cf radioisotope in 1952, researchers realized its potential as a spontaneous source of neutrons. Under the guidance of the Atomic Energy Commission, the Savannah River Laboratory (SRL) undertook an ambitious market evaluation and source fabrication program in the 1960s. Routine production of 252Cf was initiated at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL), initially from plutonium oxide target rods and ultimately from more productive recycle curium oxide target rods. The 252Cf radioisotope was then shipped to SRL for incorporation into a variety of SRL-designed sources for industrial, medical, and research applications. ORNL independently developed another line of sources, primarily for research applications. Industrial source fabrication operations were consolidated at ORNL in 1986. In 1992, SRL fabricated its last 252Cf sources. Today, most of the world's supply of 252Cf is processed, purified, and encapsulated for shipment at the Radiochemical Engineering Development Center (REDC) of ORNL

  11. Californium-252 sales and loans at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The production and distribution in the United States of 252Cf has recently been consolidated at the Oak Ridge National Laboratory (ORNL). The 252Cf Industrial Sales/Loan Program and the 252Cf University Load Program, which were formerly located at the Savannah River Plant (SRP), have been combined with the californium production and distribution activities of the Transuranium Element Production Program at ORNL. Californium-252 is sold to commercial users in the form of bulk californium oxide, palladium-californium alloy pellets, or alloy wires. Neutron source capsules, which are fabricated for loans to DOE or other US government agencies, are still available in all forms previously available. The consolidation of all 252Cf distribution activities at the production site is expected to result in better service to users. In particular, customers for neutrons sources will be ale to select from a wider range of neutron source forms, including custom designs, through a single contact point

  12. System control for the modulated 252Cf source ''Shuffler''

    International Nuclear Information System (INIS)

    The design and theory of operation of the control chassis for a 252Cf nondestructive assay system are described. This system repetitively transfers a 252Cf source from the irradiation region to a shielded position before measuring the delayed neutrons. The design criteria for the system were: rapid movement and precise positioning of the 252Cf source, precise positioning of the sample, and very accurate timing of the irradiate and count cycles. To achieve these results crystal oscillators were used for timing, and stepping motors were used to position the sample and the source. (U.S.)

  13. Boron dose enhancement for Cf-252 brachytherapy

    International Nuclear Information System (INIS)

    Full text: Monte Carlo modelling of a Cf-252 source in water and in tissue has shown that there is a significant therapeutic advantage obtained if B-10 is present in the tumour cells. This study analyses the advantage in terms of therapeutic margin, defined as the distance from the border of the treatment volume where boron-loaded tumour cells will receive a therapeutic dose. Calculations were made with MCNP version 4a on a Pentium 60 MHz computer. Large voxel sizes allowed 70 minute runs to achieve statistical uncertainties of 5% or less for 100,000 source neutrons. Later runs with smaller voxels confirmed the accuracy of the initial calculations. Calculations were made for treatment volume radii up to 11 cm and 30 ppm boron-10. The therapeutic margin for radii in the range 3-9 cm is approximately 10% of the tumour radius. This results in a 30% increase in the volume inside which peripheral tumour cells may receive a therapeutic dose. The median therapeutic ratio within the therapeutic margin varied from 1.05 at 3 cm up to 1.25 at 10 cm. Thus there is little benefit for less advanced tumours with thickness less than 3 cm. However, cervical cancer frequently presents in an advanced state in Southeast Asia and in Aboriginal communities in Australia, partially attributable to low Pap smear screening rates. These conclusions support the development and testing of boron compounds in in vitro and in vivo models for cervical cancer

  14. Survey of potential markets for devices using Californium-252

    International Nuclear Information System (INIS)

    Potential applications for devices or systems containing 252Cf in the years from 1975 to 1980 are estimated. The estimated number of devices and associated business value were derived from a survey of 46 industrial, educational and governmental organizations conducted from Jan. to May, 1975. Applications for devices and systems based on 252Cf are expected to increase by a factor of 7 in the 6-y period from 1975 to 1980. The annual business value of 252Cf devices should increase from 1.5 million dollars in 1975 to 10.8 million dollars in 1980. The potential European market should be several times as large as the US market, based on actual sales of 252Cf, which have been two to four times greater in Europe than in the US

  15. 46 CFR 252.30 - Amount of subsidy payable.

    Science.gov (United States)

    2010-10-01

    ... OPERATORS OPERATING-DIFFERENTIAL SUBSIDY FOR BULK CARGO VESSELS ENGAGED IN WORLDWIDE SERVICES Calculation of..., as described separately in § 252.32. The daily ODS rate represents the cost differential between...

  16. Prompt neutron spectrum of the spontaneous fission of californium-252

    International Nuclear Information System (INIS)

    The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

  17. 50 CFR 216.252 - Permissible methods of taking.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE... Mexico § 216.252 Permissible methods of taking. (a) Under Letters of Authorization issued pursuant...

  18. 48 CFR 53.236-2 - Architect-engineer services (SF's 252 and 330).

    Science.gov (United States)

    2010-10-01

    ... services (SF's 252 and 330). 53.236-2 Section 53.236-2 Federal Acquisition Regulations System FEDERAL... services (SF's 252 and 330). The following forms are prescribed for use in contracting for architect-engineer and related services: (a) SF 252 (Rev. 10/83), Architect-Engineer Contract. SF 252 is...

  19. Personnel exposure experience related to use of 252Cf sources

    International Nuclear Information System (INIS)

    Studies are presented of personnel exposures to 252Cf neutrons and gamma radiation during dosimetry experiments in mouse phantoms, fission foil detectors, and small tissue equivalent ionization chambers. Sensitivity of film badge emulsions to observed levels of 252Cf neutrons is discussed. Long-term personnel exposure histories are presented. Comparisons are made between neutron dose calculated from observed neutron-gamma ratios and the dose observed in neutron emulsions. Shielding used during experiments is described

  20. Production, distribution and applications of californium-252 neutron sources

    International Nuclear Information System (INIS)

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 1011 neutrons s-1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations

  1. Production, distribution and applications of californium-252 neutron sources.

    Science.gov (United States)

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

  2. Comet 252P/LINEAR: born (almost) dead?

    CERN Document Server

    Ye, Quan-Zhi; Wiegert, Paul A

    2016-01-01

    Previous studies have revealed Jupiter-family comet 252P/LINEAR as a comet that was recently transported into the near-Earth object (NEO) region in $\\sim1800$~AD yet only being weakly active. In this Letter, we examine the "formed (almost) dead" hypothesis for 252P/LINEAR using both dynamical and observational approaches. By statistically examining the dynamical evolution of 252P/LINEAR over a period of $10^7$~years, we find the median elapsed residency in the NEO region to be $4\\times10^2$~years which highlights the likelihood of 252P/LINEAR as an (almost) first-time NEO. With available cometary and meteor observations, we find the dust production rate of 252P/LINEAR to be at the order of $10^6$~kg per orbit since its entry to the NEO region. These two lines of evidence support the hypothesis that the comet was likely to have formed in a volatile-poor environment. Cometary and meteor observations during the comet's unprecedented close approach to the Earth around 2016 Mar. 21 would be useful for the understa...

  3. Californium-252 encapsulation at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    More than 1 g of the neutron-emitting isotope californium-252 has been encapsulated at SRL for worldwide medical, industrial, and research uses. Bulk sales packages have been prepared for the USDOE sales program since 1971. Doubly-encapsulated sources have been prepared for USDOE's market evaluation program since 1968. Californium-252 sources for loan and sales packages satisfy the criteria for Special Form Radioactive Material. Encapsulation is performed in special neutron-shielded containment facilities at SRL. Development of improved source and shipping package designs and processes is continuing. 17 figures

  4. Theoretical analysis of the Cf-252 fission neutron spectrum

    International Nuclear Information System (INIS)

    A complex cascade evaporation model is used to analyse energy and angular distributions of Cf-252 fission neutrons for specified scission configurations. The sensitivity of the calculation with regard to the most important input data as well as certain approximations has been studied for typical fragment mass numbers. The paper includes a brief summary on the characteristics of the scission neutron component and its influence on energy spectra and angular distributions of fission neutrons. The model was also applied to calculate the distortion of the measurable Cf-252 fission neutron spectrum by the anisotropic fragment detection in time-of-flight spectrometer arrangements. (author)

  5. Microscopic description of Cf-252 cold fission yields

    OpenAIRE

    Mirea, M.; Delion, D. S.; Sandulescu, A.

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioact...

  6. 40 CFR 264.252 - Action leakage rate.

    Science.gov (United States)

    2010-07-01

    ... 264.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Waste... for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  7. The 252Cf neutron spectrum in ISO Standard 8529

    International Nuclear Information System (INIS)

    The provenance of the 252Cf neutron spectrum tabulated in ISO Standard 8529 Part 1 is discussed in the light of queries raised in an earlier ESARDA article. It is shown that neither the ISO spectrum nor a Maxwellian representation is compatible with the most recent evaluation of this important standard spectrum.

  8. 48 CFR 252.237-7001 - Compliance with audit standards.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Compliance with audit... of Provisions And Clauses 252.237-7001 Compliance with audit standards. As prescribed in 237.270(d)(2), use the following clause: Compliance With Audit Standards (MAY 2000) The Contractor, in performance...

  9. 48 CFR 252.225-7041 - Correspondence in English.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Correspondence in English... of Provisions And Clauses 252.225-7041 Correspondence in English. As prescribed in 225.1103(2), use the following clause: Correspondence in English (JUN 1997) The Contractor shall ensure that...

  10. 48 CFR 252.247-7025 - Reflagging or repair work.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Reflagging or repair work... of Provisions And Clauses 252.247-7025 Reflagging or repair work. As prescribed in 247.574(d), use the following clause: Reflagging or Repair Work (JUN 2005) (a) Definition. Reflagging or repair...

  11. 48 CFR 252.229-7002 - Customs exemptions (Germany).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Customs exemptions... of Provisions And Clauses 252.229-7002 Customs exemptions (Germany). As prescribed in 229.402-70(b), use the following clause: Customs Exemptions (Germany) (JUN 1997) Imported products required for...

  12. Californium-252 neutron activation facility at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    A neutron irradiation facility has been established to develop new analytical methods and for the support of research programs. A major component of this facility is a 252Cf source which provides both fission spectrum and thermal neutrons. (U.S.)

  13. 24 CFR 207.252 - First, second and third premiums.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false First, second and third premiums... AUTHORITIES MULTIFAMILY HOUSING MORTGAGE INSURANCE Contract Rights and Obligations Premiums § 207.252 First, second and third premiums. The mortgagee, upon the initial endorsement of the mortgage for...

  14. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  15. 48 CFR 252.228-7000 - Reimbursement for war-hazard losses.

    Science.gov (United States)

    2010-10-01

    ...-hazard losses. 252.228-7000 Section 252.228-7000 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.228-7000 Reimbursement for war-hazard losses. As prescribed in 228.370(a), use the following clause: Reimbursement for War-Hazard Losses (DEC 1991) (a) Costs...

  16. 48 CFR 252.211-7004 - Alternate preservation, packaging, and packing.

    Science.gov (United States)

    2010-10-01

    ..., packaging, and packing. 252.211-7004 Section 252.211-7004 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.211-7004 Alternate preservation, packaging, and packing. As prescribed in 211.272, use the following provision: Alternate Preservation, Packaging, and Packing (DEC...

  17. 48 CFR 252.246-7003 - Notification of Potential Safety Issues.

    Science.gov (United States)

    2010-10-01

    ... Safety Issues. 252.246-7003 Section 252.246-7003 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.246-7003 Notification of Potential Safety Issues. As prescribed in 246.371(a), use the following clause: Notification of Potential Safety Issues (JAN 2007)...

  18. 48 CFR 252.242-7004 - Material management and accounting system.

    Science.gov (United States)

    2010-10-01

    ... accounting system. 252.242-7004 Section 252.242-7004 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.242-7004 Material management and accounting system. As prescribed in 242.7204, use the following caluse: Material Management and Accounting System (JUL 2009)...

  19. 48 CFR 252.225-7008 - Restriction on Acquisition of Specialty Metals.

    Science.gov (United States)

    2010-10-01

    ... of Specialty Metals. 252.225-7008 Section 252.225-7008 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7008 Restriction on Acquisition of Specialty Metals. As prescribed in 225.7003-5(a)(1), use the following clause: Restriction on Acquisition of Specialty Metals...

  20. 48 CFR 252.222-7005 - Prohibition on use of nonimmigrant aliens-Guam.

    Science.gov (United States)

    2010-10-01

    ... nonimmigrant aliens-Guam. 252.222-7005 Section 252.222-7005 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.222-7005 Prohibition on use of nonimmigrant aliens—Guam. As prescribed in 222.7302, use the following clause: Prohibition on Use of Nonimmigrant Aliens—Guam (SEP...

  1. 48 CFR 252.247-7023 - Transportation of supplies by sea.

    Science.gov (United States)

    2010-10-01

    ... by sea. 252.247-7023 Section 252.247-7023 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.247-7023 Transportation of supplies by sea. As prescribed in 247.573(b)(1), use the following clause: Transportation of Supplies by Sea (MAY 2002) (a) Definitions. As...

  2. 48 CFR 252.229-7008 - Relief from import duty (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... (United Kingdom). 252.229-7008 Section 252.229-7008 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.229-7008 Relief from import duty (United Kingdom). As prescribed in 229.402-70(h), use the following clause: Relief from Import Duty (United Kingdom) (JUN...

  3. 48 CFR 252.216-7001 - Economic price adjustment-nonstandard steel items.

    Science.gov (United States)

    2010-10-01

    ...-nonstandard steel items. 252.216-7001 Section 252.216-7001 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.216-7001 Economic price adjustment—nonstandard steel items. As prescribed in 216.203-4-70(b), use the following clause: Economic Price Adjustment—Nonstandard Steel...

  4. 48 CFR 252.222-7004 - Compliance with Spanish social security laws and regulations.

    Science.gov (United States)

    2010-10-01

    ... Condition of the Enterprise) from the Ministerio de Trabajo y S.S., Tesoreria General de la Seguridad Social... social security laws and regulations. 252.222-7004 Section 252.222-7004 Federal Acquisition Regulations... PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.222-7004 Compliance with Spanish...

  5. 48 CFR 252.225-7011 - Restriction on acquisition of supercomputers.

    Science.gov (United States)

    2010-10-01

    ... of supercomputers. 252.225-7011 Section 252.225-7011 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7011 Restriction on acquisition of supercomputers. As prescribed in 225.7012-3, use the following clause: Restriction on Acquisition of Supercomputers (JUN...

  6. Microscopic description of Cf-252 cold fission yields

    CERN Document Server

    Mirea, M; Sandulescu, A

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioactivity, related the other two "magic radioactivities", namely alpha-decay and heavy-cluster decay, called also Pb-like radioactivity. This calculation provides the necessary theoretical confidence to estimate the penetration cross section in producing superheavy nuclei, by using the inverse fusion process.

  7. A pneumatic transfer system for special form 252Cf

    International Nuclear Information System (INIS)

    A pneumatic transfer system has been developed for use with series 100 Special Form 252Cf. It was developed to reduce the exposure to personnel handling sources of 252Cf with masses up to 150 microg by permitting remotely activated two-way transfer between the storage container and the irradiation position. The pneumatic transfer system also permits transfers for reproducible repetitive irradiation periods. In addition to the storage container equipped with quick-release fittings, the transfer system consists of an irradiation station, a control box with momentary contact switches to activate the air-pressure control valves and indicators to identify the location of the source, and connecting air hose and electrical wire. A source of 20 psig air and 110 volt electrical power are required for operation of the transfer system which can be easily moved and set up by one individual in 5 to 10 minutes. Tests have shown that rarely does a source become lodged in the transfer tubing, but two methods have been developed to handle incomplete transfers of the 252Cf source. The first method consists of closing one air vent to allow a pressure impulse to propel the source to the opposite side. The second method applies to those 252Cf capsules with a threaded or tapped end to which a small ferromagnetic piece can be attached; an incompletely transferred source in the transfer tube can then be guided to a position of safety by surrounding the transfer tubing containing the capsule with a horseshoe magnet attached to the end of a long pole

  8. Material recognition by using a tagged {sup 252}Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Viesti, G. [Dipartimento di Fisica dell Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)], E-mail: viesti@pd.infn.it; Cossutta, L. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); Fabris, D. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Lunardon, M.; Moretto, S. [Dipartimento di Fisica dell Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nebbia, G.; Pesente, S. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Pino, F.; Sajo-Bohus, L. [Universidad Simon-Bolivar, Laboratorio Fisica Nuclear, Apartado 8900, 1080 A. Caracas (Venezuela, Bolivarian Republic of)

    2008-08-11

    Material recognition by measuring simultaneously the transmission of neutron and gamma ray produced by a {sup 252}Cf source has been studied, determining the average atomic number resolving power. In addition, it is demonstrated the possibility to derive direct signatures able to identify light elements (C, N, O) using the measured transmission versus neutron time-of-flight. This allows one to determine the relevant elemental ratios (C/O and C/N) normally used to identify threat organic materials such as explosives and drugs.

  9. Terahertz Transmission Imaging with 2.52 THz Continuous Wave

    Institute of Scientific and Technical Information of China (English)

    Xiao-Tong Guan; De-Wei Zheng; Min Hu; Wen-Jie Fu; Yu-Meng Cui; Xiang Fan; Liang Zhang; Ye Yuan; Jing-Yuan Xu; Yuan Li

    2013-01-01

    In this article, two terahertz transmission imaging systems are built with a 2.52 THz continuous wave laser and two types of sensors. One is array scanning system using a 124×124 pyro-electric array camera as the detector; the other is a point-wise scanning system utilizing a Golay cell as the detector. The imaging speed and quality is briefly analyzed. Terahertz (THz) imaging results demonstrate that the array scanning system has higher imaging speed with lower resolution. The point-wise scanning system has higher imaging quality with lower speed.

  10. 48 CFR 252.225-7016 - Restriction on acquisition of ball and roller bearings.

    Science.gov (United States)

    2010-10-01

    ... of ball and roller bearings. 252.225-7016 Section 252.225-7016 Federal Acquisition Regulations System... and roller bearings. As prescribed in 225.7009-5, use the following clause: Restriction on Acquisition of Ball and Roller Bearings (MAR 2006) (a) Definitions. As used in this clause' (1)...

  11. 48 CFR 252.205-7000 - Provision of information to cooperative agreement holders.

    Science.gov (United States)

    2010-10-01

    ... to cooperative agreement holders. 252.205-7000 Section 252.205-7000 Federal Acquisition Regulations... cooperative agreement holders. As prescribed in 205.470, use the following clause: Provision of Information to Cooperative Agreement Holders (DEC 1991) (a) Definition. Cooperative agreement holder means a State or...

  12. 24 CFR 220.252 - Forbearance of foreclosure and assignment of mortgage.

    Science.gov (United States)

    2010-04-01

    ... assignment of mortgage. 220.252 Section 220.252 Housing and Urban Development Regulations Relating to Housing... COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE AND INSURED IMPROVEMENT LOANS FOR URBAN RENEWAL...

  13. 48 CFR 252.222-7006 - Restrictions on the Use of Mandatory Arbitration Agreements.

    Science.gov (United States)

    2010-10-01

    ... Mandatory Arbitration Agreements. 252.222-7006 Section 252.222-7006 Federal Acquisition Regulations System... Arbitration Agreements. As prescribed in 222.7404, use the following clause: Restrictions on the Use of Mandatory Arbitration Agreements (MAY 2010) (a) Definitions. As used in this clause— Covered...

  14. 48 CFR 252.247-7024 - Notification of transportation of supplies by sea.

    Science.gov (United States)

    2010-10-01

    ... transportation of supplies by sea. 252.247-7024 Section 252.247-7024 Federal Acquisition Regulations System... supplies by sea. As prescribed in 247.574(c), use the following clause: Notification of Transportation of Supplies by Sea (MAR 2000) (a) The Contractor has indicated by the response to the solicitation...

  15. 48 CFR 252.247-7022 - Representation of extent of transportation by sea.

    Science.gov (United States)

    2010-10-01

    ... of transportation by sea. 252.247-7022 Section 252.247-7022 Federal Acquisition Regulations System... transportation by sea. As prescribed in 247.574(a), use the following provision: Representation of Extent of Transportation By Sea (AUG 1992) (a) The Offeror shall indicate by checking the appropriate blank in paragraph...

  16. 48 CFR 252.227-7027 - Deferred ordering of technical data or computer software.

    Science.gov (United States)

    2010-10-01

    ... technical data or computer software. 252.227-7027 Section 252.227-7027 Federal Acquisition Regulations... data or computer software. As prescribed at 227.7103-8(b), use the following clause: Deferred Ordering of Technical Data or Computer Software (APR 1988) In addition to technical data or computer...

  17. 48 CFR 252.227-7019 - Validation of asserted restrictions-Computer software.

    Science.gov (United States)

    2010-10-01

    ... restrictions-Computer software. 252.227-7019 Section 252.227-7019 Federal Acquisition Regulations System...—Computer software. As prescribed in 227.7104(e)(3) or 227.7203-6(c), use the following clause: Validation of Asserted Restrictions—Computer Software (JUN 1995) (a) Definitions. (1) As used in this...

  18. 48 CFR 252.227-7026 - Deferred delivery of technical data or computer software.

    Science.gov (United States)

    2010-10-01

    ... technical data or computer software. 252.227-7026 Section 252.227-7026 Federal Acquisition Regulations... data or computer software. As prescribed at 227.7103-8(a), use the following clause: Deferred Delivery of Technical Data or Computer Software (APR 1988) The Government shall have the right to require,...

  19. 38 CFR 3.252 - Annual income; pension; Mexican border period and later war periods.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Annual income; pension; Mexican border period and later war periods. 3.252 Section 3.252 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity...

  20. 48 CFR 252.223-7004 - Drug-free work force.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Drug-free work force. 252... Provisions And Clauses 252.223-7004 Drug-free work force. As prescribed in 223.570-2, use the following clause: Drug-Free Work Force (SEP 1988) (a) Definitions. (1) Employee in a sensitive position, as used...

  1. 48 CFR 252.229-7010 - Relief from customs duty on fuel (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... on fuel (United Kingdom). 252.229-7010 Section 252.229-7010 Federal Acquisition Regulations System... (United Kingdom). As prescribed in 229.402-70(j), use the following clause: Relief from Customs Duty on Fuel (United Kingdom) (JUN 1997) (a) Pursuant to an agreement between the United States Government...

  2. 48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

    Science.gov (United States)

    2010-10-01

    ... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and...

  3. 48 CFR 252.203-7002 - Requirement to Inform Employees of Whistleblower Rights.

    Science.gov (United States)

    2010-10-01

    ... Employees of Whistleblower Rights. 252.203-7002 Section 252.203-7002 Federal Acquisition Regulations System... Whistleblower Rights. As prescribed in 203.970, use the following clause: Requirement To Inform Employees of Whistleblower Rights (JAN 2009) The Contractor shall inform its employees in writing of employee...

  4. 48 CFR 252.245-7000 - Government-furnished mapping, charting, and geodesy property.

    Science.gov (United States)

    2010-10-01

    ... mapping, charting, and geodesy property. 252.245-7000 Section 252.245-7000 Federal Acquisition Regulations..., charting, and geodesy property. As prescribed in 245.107-70, use the following clause: Government-Furnished Mapping, Charting, and Geodesy Property (DEC 1991) (a) Definition—Mapping, charting, and geodesy...

  5. 48 CFR 252.227-7014 - Rights in noncommercial computer software and noncommercial computer software documentation.

    Science.gov (United States)

    2010-10-01

    ... container and each page, or portions thereof, of printed material containing computer software for which... computer software and noncommercial computer software documentation. 252.227-7014 Section 252.227-7014... Rights in noncommercial computer software and noncommercial computer software documentation....

  6. The Extreme Type I Planetary Nebula M2-52

    Directory of Open Access Journals (Sweden)

    M. Peña

    2002-01-01

    Full Text Available Se presentan los resultados obtenidos a partir de espectroscopía de alta resolución de la parte central de la nebulosa planetaria bipolar M2-52 que muestra un tipo morfológico Br. Hemos confirmado que M2-52 es una nebulosa de Tipo I de Peimbert, con un espectro rico en líneas de alto y bajo grado de ionización y un fuerte enriquecimiento de He y N. La composición química del gas ionizado es: He/H = 0:165 0:010, O/H = (2:6 0:5 x 10_4, N/O = 2:3 0:3, Ne/O = 0:37 0:10, Ar/O = (9:2 2:0 x 10_3 y S/O > 2:0 x 10_3. La velocidad de expansión de la nebulosa es, en promedio, de 20 2 km s_1 y varía ligeramente dependiendo del ión considerado. Los iones de menor grado de ionización, N+ y S+, muestran vexp _ 18 km s_1, O++ y He+ muestran vexp _ 20 km s_1, en tanto que He++ y H+ muestran vexp _ 22 km s_1. Es posible que la zona de N+ y S+ esté siendo frenada por el anillo de material molecular encontrado alrededor de la estrella.

  7. Brachytherapy of carcinoma of vulva with 252Cf

    International Nuclear Information System (INIS)

    Thirty patients with carcinoma of vulva were treated with interstitial neutron radiotherapy with 252Cf. Age of patients was from 32 to 83 years. Stage I was in I patient, stage II - in 12, stage III was in 10 patients. The diagnosis of vulvar cancer was made for the first time in 11 cases, 19 patients had recurrences after the initial treatment. Most of these patients also received external irradiation for cancer of vulva and bilateral inguinal sites with a single fraction dose of 2 Gy to a total dose 30-50 Gy. Enlarged inguinal lymph nodes were irradiated additionally to 60 Gy with reduced field of irradiation. When radiotherapy was used repeatedly interstitial brachytherapy comprised the major part of irradiation dose or the therapy was used alone delivering 35-55 iGy. We used 252Cf sources with increased activity at the ends 20-30 mm long. A number of inserted sources varied from 2 to 10, irradiation dose rate from 20.3 to 236.7 cGy/h, time of irradiation from 10.2 to 12. hours, RBE from 4.6 to 6.33. Special template device made it possible to implant sources in strictly pre-set geometry. Analysis of survival of patients showed that 2 years survival was 66%, 3 years - 60%, and 5 years survival was 49%. In two cases necrotic epithelitis developed with following radiation ulcer which were cured in 3-4 months. Clinical data showed great effectiveness of interstitial neutron therapy having in mind that 19 patients were treated for recurrences of vulvar cancer after previuos treatment

  8. Neutron Spectra, Fluence and Dose Rates from Bare and Moderated Cf-252 Sources

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-01

    A new, stronger 252Cf source (serial number SR-CF-3050-OR) was obtained from Oak Ridge National Laboratory (ORNL) in 2014 to supplement the existing 252Cf sources which had significantly decayed. A new instrument positioning track system was designed and installed by Hopewell Designs, Inc. in 2011. The neutron field from the new, stronger 252Cf source in the modified calibration environment needed to be characterized as well as the modified neutron fields produced by the new source and seven different neutron moderators. Comprehensive information about our 252Cf source, its origin, production, and isotopic content and decay characteristics needed to be compiled as well. This technical report is intended to address these issues.

  9. Development of high-activity 252Cf sources for neutron brachytherapy

    International Nuclear Information System (INIS)

    The Gershenson Radiation Oncology Center of Wayne State University (WSU), Detroit, Michigan, is using 252Cf medical sources for neutron brachytherapy. These sources are based on a 20-year-old design containing ≤ 30 microg 252Cf in the form of a cermet wire of Cf2O3 in a palladium matrix. The Radiochemical Engineering Development Center (REDC) of Oak Ridge National Laboratory has been asked to develop tiny high-activity 252Cf neutron sources for use with remote afterloading equipment to reduce treatment times and dose to clinical personnel and to expedite treatment of brain and other tumors. To date, the REDC has demonstrated that 252Cf loadings can be greatly increased in cermet wires much smaller than before. Equipment designed for hot cell fabrication of these wires is being tested. A parallel program is under way to relicense the existing source design for fabrication at the REDC

  10. Functional design criteria for project W-252, phase II liquid effluent treatment and disposal. Revision 2

    International Nuclear Information System (INIS)

    This document is the Functional Design Criteria for Project W-252. Project W-252 provides the scope to provide BAT/AKART (best available technology...) to 200 Liquid Effluent Phase II streams (B-Plant). This revision (Rev. 2) incorporates a major descoping of the project. The descoping was done to reflect a combination of budget cutting measures allowed by a less stringent regulatory posture toward the Phase II streams

  11. Role of antibiotic production by Erwinia herbicola Eh252 in biological control of Erwinia amylovora.

    OpenAIRE

    Vanneste, J L; Yu, J.; Beer, S V

    1992-01-01

    Erwinia herbicola Eh252 is a nonpathogenic epiphytic bacterium that reduces fire blight incidence when sprayed onto apple blossoms before inoculation with Erwinia amylovora, the causal agent of fire blight. Eh252 was found to produce on minimal medium an antibiotic that inhibited the growth of E. amylovora. This antibiotic was inactivated by histidine but not by Fe(II), was sensitive to proteolytic enzymes, and showed a narrow host range of activity. To determine the role of this antibiotic i...

  12. Termocoagulación facetaria lumbar: Experiencia en 252 pacientes Thermocoagulation of lumbar facet joints: Experience in 252 patients

    Directory of Open Access Journals (Sweden)

    J. E. Martínez-Suárez

    2005-10-01

    Full Text Available Se presentan 252 pacientes con el diagnóstico de dolor lumbar facetario a los que se le realizó la técnica quirúrgica de termocoagulación percutánea de la faceta articular. Nuestro propósito principal fue aliviar el dolor en estos pacientes, evaluamos la eficacia de la técnica con un 74,7% de resultados quirúrgicos satisfactorios, así como la descripción de diferentes aspectos como: edad, sexo, causas y la topografía segmentaria del dolor.Two hundred fifty two patients with diagnosis of lumbar facet joint pain underwent the surgical technique of percutaneous thermocoagulation of the facet joint. Our major aim was to relief pain in those patients. We assess the effectiveness of the technique, with 74.7% of surgical success, and we also describe different aspects such as: age, sex, causes and segmentary pain topography.

  13. Attributes and templates from active measurements with 252Cf

    International Nuclear Information System (INIS)

    Active neutron interrogation is useful for the detection of shielded HEU and could also be used for Pu. In an active technique, fissile material is stimulated by an external neutron source to produce fission with the emanation of neutrons and gamma rays. The time distribution of particles leaving the fissile material is measured with respect to the source emission in a variety of ways. A variety of accelerator and radioactive sources can be used. Active interrogation of nuclear weapons/components can be used in two ways: template matching or attribute estimation. Template matching compares radiation signatures with known reference signatures and for treaty applications has the problem of authentication of the reference signatures along with storage and retrieval of templates. Attribute estimation determines, for example, the fissile mass from various features of the radiation signatures and does not require storage of radiation signatures but does require calibration, which can be repeated as necessary. A nuclear materials identification system (NMIS) has been in use at the Oak Ridge Y-12 Plant for verification of weapons components being received and in storage by template matching and has been used with calibrations for attribute (fissile mass) estimation for HEU metal. NMIS employs a 252Cf source of low intensity (6 n/sec) such that the dose at 1 m is approximately twice that on a commercial airline at altitude. The use of such a source presents no significant safety concerns either for personnel or nuclear explosive safety, and has been approved for use at the Pantex Plant on fully assembled weapons systems

  14. Automated absolute activation analysis with californium-252 sources

    Energy Technology Data Exchange (ETDEWEB)

    MacMurdo, K.W.; Bowman, W.W.

    1978-09-01

    A 100-mg /sup 252/Cf neutron activation analysis facility is used routinely at the Savannah River Laboratory for multielement analysis of many solid and liquid samples. An absolute analysis technique converts counting data directly to elemental concentration without the use of classical comparative standards and flux monitors. With the totally automated pneumatic sample transfer system, cyclic irradiation-decay-count regimes can be pre-selected for up to 40 samples, and samples can be analyzed with the facility unattended. An automatic data control system starts and stops a high-resolution gamma-ray spectrometer and/or a delayed-neutron detector; the system also stores data and controls output modes. Gamma ray data are reduced by three main programs in the IBM 360/195 computer: the 4096-channel spectrum and pertinent experimental timing, counting, and sample data are stored on magnetic tape; the spectrum is then reduced to a list of significant photopeak energies, integrated areas, and their associated statistical errors; and the third program assigns gamma ray photopeaks to the appropriate neutron activation product(s) by comparing photopeak energies to tabulated gamma ray energies. Photopeak areas are then converted to elemental concentration by using experimental timing and sample data, calculated elemental neutron capture rates, absolute detector efficiencies, and absolute spectroscopic decay data. Calculational procedures have been developed so that fissile material can be analyzed by cyclic neutron activation and delayed-neutron counting procedures. These calculations are based on a 6 half-life group model of delayed neutron emission; calculations include corrections for delayed neutron interference from /sup 17/O. Detection sensitivities of < or = 400 ppB for natural uranium and 8 ppB (< or = 0.5 (nCi/g)) for /sup 239/Pu were demonstrated with 15-g samples at a throughput of up to 140 per day. Over 40 elements can be detected at the sub-ppM level.

  15. Antibiosis Contributes to Biological Control of Fire Blight by Pantoea agglomerans Strain Eh252 in Orchards.

    Science.gov (United States)

    Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

    2002-11-01

    ABSTRACT Fire blight, caused by Erwinia amylovora, is the most serious bacterial disease of pear and apple trees. Biological control with strains of Pantoea agglomerans (syn. Erwinia herbicola) may provide an effective disease management strategy for fire blight. Most strains of P. agglomerans evaluated for suppression of fire blight produce compounds that inhibit the growth of E. amylovora in culture. The role of these inhibitory compounds in fire blight suppression in orchard environments has not been studied. In seven field trials in Oregon, we compared the population dynamics and disease suppression with P. agglomerans Eh252, a strain that produces a single antibiotic, with its near-isogenic antibiotic-deficient derivative, strain 10:12. Water or suspensions of Eh252 or 10:12 (1 x 10(8) CFU/ml) were applied at 30 and 70% bloom to pear or apple trees. Aqueous suspensions of freeze-dried cells of E. amylovora (3 x 10(5) CFU/ml) were applied at full bloom. Additional trees were treated with streptomycin or oxytetracycline at 30 and 70% bloom and in some experiments, 1 day after application of the pathogen. Population sizes of Eh252 or 10:12 on pear blossoms were estimated by spreading dilutions of blossom washes on culture media. Average population sizes of Eh252 and 10:12 on blossoms ranged from 10(5) to 10(7) CFU, and in five of six trials, the relative area under the population curve of Eh252 was not significantly different than that of its derivative 10:12. Both Eh252 and 10:12 reduced the growth of the pathogen on blossoms compared with inoculated water-treated controls. Eh252 significantly decreased the incidence of fire blight in six of seven field trials compared with the incidence on water-treated trees, and 10:12 similarly reduced the incidence of fire blight in four of seven trials. In three of seven field trials, trees treated with Eh252 had a significantly lower incidence of fire blight compared with trees treated 3 with 10:12. Overall,3 Eh252 reduced

  16. Long-term effects of an intracavitary treatment with californium-252 on normal tissue

    International Nuclear Information System (INIS)

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with 252Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from 252Cf and 7000 rad from 226Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for 252Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from 252Cf and 5000 rad from 226Ra

  17. Effects of 252Cf neutrons, transmitted through an iron block on human lymphocyte chromosome

    International Nuclear Information System (INIS)

    Chromosome aberration of human peripheral blood lymphocytes exposed to californium-252 (252Cf) neutrons transmitted through a 15 cm thick iron block was analysed. The spectrum of the filtered neutrons ranged from 0.1 to 2MeV with a peak at 0.7 MeV, simulating the Hiroshima atomic bomb neutron spectrum as shown in the Dosimetry System 1986 (DS86). Chromosome aberration frequencies after exposure to filtered and unfiltered 252Cf radiation were compared. Acentric ring chromosomes were significantly increased (p 0.1). The relative biological effectiveness (RBE) of the neutrons with respect to the formation of dicentrics and centric rings was 10.9 and 12.3 in the filtered and unfiltered conditions respectively, but the difference was not statistically significant. These results provide useful information for the re-evaluation of the biological effect of the Hiroshima atomic bomb radiations. (Author)

  18. Relative biological efficiency of powerful 252Cf mixed α-neutron radiation

    International Nuclear Information System (INIS)

    Comprehensive radiobiological studies of the relative biological and genetic efficacy (RBE and RGE) of powerful 252Cf radiation (the ANET-B unit) were conducted using research tools of various radiosensitivity (bacteria, Drosophila, Chinese hamster cells, murine thymocytes, human and murine bone marrow stem cells, human peripheral blood lymphocytes, Lewis lung carcinoma cells). It was shown in the tests of reproductive or interphase death and chromosome aberrations that the RBE and the RGE values of a sup(252)Cf new source varied within the same limits from 1.3 to 3.0 whereas in the tests of gene mutations the RGE of the source did not exceed the efficacy of 60Co γ-radiation and in some cases it was much lower. Thus the RBE of the new source in induced lethal and chromosome demages was 2-4 times lower than the efficacy of a low-activity sup(252)Cf source used now in radiotherapy

  19. Response of CR-39 plastic track detector to 239Pu and 252Cf sources

    International Nuclear Information System (INIS)

    CR-39 plastic track detectors have been irradiated with 239Pu and 252Cf sources separately at nuclear physics laboratory B.H.U., Varanasi to investigate track recording properties of detector material. All detectors etched in 6.25N NaOH solution at different temperatures for different hours. The bulk and track etch rates are calculated for both detectors (irradiated by 239Pu and 252Cf sources separately). The diameter and sensitivity along the trajectory of the track have been determined at different temperatures. (author)

  20. Water-extended polyester neutron shield for a 252Cf neutron source

    International Nuclear Information System (INIS)

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, 252Cf and shielding were modelled and the neutron spectra as well as the H*(10) were calculated in four sites. The calculation was extended to include a water shielding, the source in vacuum and in air. Besides neutron shielding characteristics, the Kerma in air due to gammas emitted by 252Cf and due to capture γ rays in the shielding were included. (authors)

  1. 24 CFR 207.252c - Premiums-mortgages insured pursuant to section 238(c) of the Act.

    Science.gov (United States)

    2010-04-01

    ... HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MULTIFAMILY HOUSING MORTGAGE INSURANCE Contract Rights.... All of the provisions of §§ 207.252 and 207.252a governing mortgage insurance premiums shall apply...

  2. 48 CFR 252.229-7009 - Relief from customs duty and value added tax on fuel (passenger vehicles) (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... and value added tax on fuel (passenger vehicles) (United Kingdom). 252.229-7009 Section 252.229-7009... Relief from customs duty and value added tax on fuel (passenger vehicles) (United Kingdom). As prescribed in 229.402-70(i), use the following clause: Relief from Customs Duty and Value Added Tax on...

  3. 48 CFR 252.209-7001 - Disclosure of ownership or control by the government of a terrorist country.

    Science.gov (United States)

    2010-10-01

    ... control by the government of a terrorist country. 252.209-7001 Section 252.209-7001 Federal Acquisition... ownership or control by the government of a terrorist country. As prescribed in 209.104-70(a), use the following provision: Disclosure of Ownership or Control by the Government of a Terrorist Country (JAN...

  4. 40 CFR 436.252 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Effluent limitations guidelines... technology currently available. 436.252 Section 436.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE...

  5. 47 CFR 51.809 - Availability of agreements to other telecommunications carriers under section 252(i) of the Act.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Availability of agreements to other telecommunications carriers under section 252(i) of the Act. 51.809 Section 51.809 Telecommunication FEDERAL... Implementation of Section 252 of the Act § 51.809 Availability of agreements to other telecommunications...

  6. 48 CFR 252.227-7039 - Patents-reporting of subject inventions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Patents-reporting of... CLAUSES Text of Provisions And Clauses 252.227-7039 Patents—reporting of subject inventions. As prescribed in 227.303(1), use the following clause: Patents—Reporting of Subject Inventions (APR 1990)...

  7. 48 CFR 252.227-7012 - Patent license and release contract.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Patent license and release... of Provisions And Clauses 252.227-7012 Patent license and release contract. As prescribed at 227.7012, insert the following clause in patent releases, license agreements, and assignments: (Contract...

  8. 46 CFR 252.22 - Substantiality and extent of foreign-flag competition.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Substantiality and extent of foreign-flag competition... WORLDWIDE SERVICES Operation § 252.22 Substantiality and extent of foreign-flag competition. (a) Type and tonnage groupings. Foreign-flag competition shall be determined, as of January 1 of the year...

  9. 48 CFR 252.219-7003 - Small business subcontracting plan (DoD contracts).

    Science.gov (United States)

    2010-10-01

    ... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.219-7003 Small business subcontracting plan...-9, Small Business Subcontracting Plan, clause of this contract. (a) Definitions. Historically black... Education to meet the requirements of 34 CFR 608.2. The term also means any nonprofit research...

  10. Combination of HPLC and 252-Cf plasma desorption mass spectrometry for identifying composition of ginseng tinctures.

    Science.gov (United States)

    Elkin, Y N; Makhankov, V V; Uvarova, N L; Bondarenko, P V; Zubarev, R A; Knysh, A N

    1993-03-01

    The 252-Cf plasma desorption mass spectrometry (252-Cf PDMS) determination or confirmation of the ginsenoside saponins has been proposed to investigate the composition of high performance liquid chromatography (HPLC) peaks of ginseng tinctures and galenic preparations. That ionization technique is well suitable for the analysis of natural mixtures of these saponins. The 252-Cf PD mass spectra of standard ginsenosides Rb1, Rb2, Rc, Re, Rg1, Rd, NG-R2, Z-R1 contain the peaks of two types of ions, namely, molecular adduct ions (MAI) and aglycone ions. By mass the latter may be referred to either protopanaxadiol or protopanaxatriol. The masses of MAI and aglycone ions are determined by the carbohydrate chains. The collected HPLC fractions of P ginseng tincture can be tested for content of ginsenosides. After studying two MAI peaks from the 252-Cf PD mass spectra of the basic ginsenosides, an example of distinction between two galenic preparations from different Panax has been shown. PMID:8352021

  11. LARGE GAMMA ANISOTROPY OBSERVED IN THE CF-252 SPONTANEOUS-FISSION PROCESS

    NARCIS (Netherlands)

    VANDERPLOEG, H; BACELAR, JC; VANDENBERG, T; IACOB, VE; JONGMAN, [No Value; VANDERWOUDE, A

    1992-01-01

    The energy spectrum and the angular dependence relative to the fission direction of photons in the energy region between 2 and 40 MeV have been measured for the spontaneous fission of Cf-252. A large anisotropy was found in the energy region 8 to 12 MeV implying that photons in this region are emitt

  12. STUDY OF THE GAMMA EMISSION PROBABILITY ACCOMPANYING THE SPONTANEOUS FISSION OF CF-252

    NARCIS (Netherlands)

    VANDERPLOEG, H; LAURENS, CR; BACELAR, JCS; BUDA, A; GAARDHOJE, JJ; VANTHOF, G; KALANTARNAYESTANAKI, N; VANDERWOUDE, A; ZELAZNY, Z

    1994-01-01

    A study of the gamma emission accompanying the spontaneous fission process of Cf-252 has been performed. The photon emission probability between 3 and 70 MeV and its angular dependence with respect to the fission direction were measured. These measurements were performed as a function of the mass as

  13. 48 CFR 252.228-7006 - Compliance with Spanish laws and insurance.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Compliance with Spanish... CLAUSES Text of Provisions And Clauses 252.228-7006 Compliance with Spanish laws and insurance. As prescribed at 228.370(e), use the following clause: Compliance with Spanish Laws and Insurance (DEC 1998)...

  14. OER of californium-252 at low dose rate for growth inhibition in Vicia faba

    International Nuclear Information System (INIS)

    OER of 252Cf, at low dose rate, has been determined for growth inhibition in Vicia faba roots. A new strain ''BelB'' was used; it was found to be more resistant to prolonged anoxia. Two sets of linear 252Cf sources were used (linear activity 0.31 and 0.47 (μg.cm-1)) in somewhat different geometrical arrangements. The (n+γ) 252Cf dose rates at the level of the root tips were 0.11 and 0.13 Gy.h-1 respectively. The relative contribution of the γ component Dsub(γ) to the total absorbed dose Dsub(n+γ) at the level of the root tips was evaluated Dsub(γ)/Dsub(n+γ)=0.35 for the first source-geometry and 0.42 for the second source-geometry. The reference radiation was the γ emission of 192Ir, used in the same geometrical conditions and for similar irradiation times. Irradiations performed in aerobic and anoxic conditions were alternated. OER values of 1.4 +- 0.1 and 1.5 +- 0.1 were observed for the 252Cf emission with the first and second source-geometry respectively. The corresponding OER values for 192Ir were 2.3 +- 0.2 and 2.6 +- 0.1; the derived oxygen gain factors were then equal to 1.6 and 1.7 repectively

  15. 48 CFR 252.239-7016 - Telecommunications security equipment, devices, techniques, and services.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Telecommunications... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.239-7016 Telecommunications... clause: Telecommunications Security Equipment, Devices, Techniques, and Services (DEC 1991)...

  16. 48 CFR 252.239-7012 - Title to telecommunication facilities and equipment.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Title to telecommunication... CLAUSES Text of Provisions And Clauses 252.239-7012 Title to telecommunication facilities and equipment. As prescribed in 239.7411(b), use the following clause: Title to Telecommunication Facilities...

  17. 48 CFR 252.229-7006 - Value added tax exclusion (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Value added tax exclusion... CLAUSES Text of Provisions And Clauses 252.229-7006 Value added tax exclusion (United Kingdom). As prescribed in 229.402-70(f), use the following clause: Value Added Tax Exclusion (United Kingdom) (JUN...

  18. 48 CFR 252.229-7011 - Reporting of Foreign Taxes-U.S. Assistance Programs.

    Science.gov (United States)

    2010-10-01

    ... all value added taxes and customs duties imposed by the recipient country. This exemption is in... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Reporting of Foreign Taxes... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.229-7011 Reporting of Foreign...

  19. 50 CFR 14.252 - What definitions do I need to know?

    Science.gov (United States)

    2010-10-01

    ... by the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) under the Animal Welfare Act (AWA) (7 U.S.C. 2131 et seq.) (See definition of “licensee” in 9 CFR 1.1.). Prohibited... PLANTS IMPORTATION, EXPORTATION, AND TRANSPORTATION OF WILDLIFE Captive Wildlife Safety Act § 14.252...

  20. 48 CFR 252.225-7045 - Balance of Payments Program-Construction Material Under Trade Agreements.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Balance of Payments... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.225-7045 Balance of Payments... clause: Balance of Payments Program—Construction Material Under Trade Agreements (NOV 2009)...

  1. 48 CFR 252.225-7044 - Balance of Payments Program-Construction Material.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Balance of Payments... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.225-7044 Balance of Payments Program—Construction Material. As prescribed in 225.7503(a), use the following clause: Balance of Payments...

  2. 48 CFR 252.232-7003 - Electronic submission of payment requests and receiving reports.

    Science.gov (United States)

    2010-10-01

    ... PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.232-7003 Electronic submission of payment... administering the contract for payment has determined, in writing, that electronic submission would be unduly... non-electronic payment requests using the method or methods specified in Section G of the contract....

  3. Multi-element neutron activation analysis of sediment using a californium-252 source

    International Nuclear Information System (INIS)

    The application of a 252Cf source to the neutron activation analysis of several elements in small (approximately 1.5 in. in dia) cores was studied using high-resolution gamma ray spectroscopy and manual data reduction. (U.S.)

  4. 48 CFR 252.225-7032 - Waiver of United Kingdom Levies-Evaluation of offers.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Waiver of United Kingdom... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.225-7032 Waiver of United Kingdom Levies—Evaluation of offers. As prescribed in 225.1101(8), use the following provision: Waiver of United...

  5. 48 CFR 252.225-7033 - Waiver of United Kingdom levies.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Waiver of United Kingdom... of Provisions And Clauses 252.225-7033 Waiver of United Kingdom levies. As prescribed in 225.1101(9), use the following clause: Waiver of United Kingdom Levies (APR 2003) (a) The U.S. Government...

  6. Remark on the prompt-fission-neutron spectrum of 252Cf

    International Nuclear Information System (INIS)

    Good resolution time-of-flight measurements show small structure in the prompt fission neutron spectrum of 252Cf that is identified with air-scattering effects. The observed high energy portion of the neutron spectrum is consistent with a Maxwellian distribution having a temperature of 1.42 MeV

  7. 48 CFR 252.222-7003 - Permit from Italian Inspectorate of Labor.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Permit from Italian... CLAUSES Text of Provisions And Clauses 252.222-7003 Permit from Italian Inspectorate of Labor. As prescribed in 222.7201(b), use the following clause: Permit from Italian Inspectorate of Labor (JUN...

  8. 7 CFR 1710.252 - Construction work plans-power supply borrowers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Construction work plans-power supply borrowers. 1710... LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.252 Construction work plans..., environmental and other studies and plans needed to support the construction of facilities, when such cost...

  9. Clinical Report on Californium-252 Neutron Intraluminal Brachytherapy Combined with External Irradiation for Cervical Carcinoma Treatment

    Institute of Scientific and Technical Information of China (English)

    Huanyu Zhao; Keming Wang; Jian Sun; Xin Geng; Weiming Zhang

    2006-01-01

    OBJECTIVE To observe the curative effects and complications of californium-252 (252Cf) neutron intraluminal brachytherapy (IBT) combined with external irradiation (El) for treatment of cervical carcinoma.METHODS From December 2000 to December 2004, 128 cases of cervical carcinoma staged into ⅡA~ⅢB according to the International Federation of Gynecology and Obstetrics (FIGO) standards were treated with 252Cf neutron IBT using 8~10 Gy per fraction, once a week. The total dose at reference A point was 36~40 Gy in 4~5 fractions. From the second day after 252Cf neutron IBT treatment, the whole pelvic cavity was treated with 60Co γ-ray El, applying 2 Gy per fraction, 4 times per week. After 20~25 Gy of El, the center of the whole pelvic field was blocked with 4 cm of lead in width. The total dose of El was 45~50 Gy.RESULTS The short-term therapeutic effects were CR 95.3% and PR 4.7%. The 3 and 5-year local control rates were 93.5% and 87.9%. The overall 3-year survival rate was 87.5% and for Stages Ⅱ and Ⅲ , 90.9%and 81.5% respectively; the overall 5-year survival rate was 70% and for Stages Ⅱ and Ⅲ, 76.2% and 61% respectively. The rate of radiation complications was 4.7% for radiation cystitis, 7.8% for radiation proctitis, 6.3%for vagina contracture and adhesion and 5.5% for protracted radiation proctitis.CONCLUSION An combination of 252Cf neutron IBT with El for treatment of cervical carcinoma can be well-tolerated by cervical carcinoma patients. The rate of local tumor control is high and radiation complications are few.

  10. 利用示踪252Cf中子源的材料鉴别技术%Material Recognition by Using 252Cf Source

    Institute of Scientific and Technical Information of China (English)

    郝昕; L. Sajo-Bohus; 竺礼华; L. Stevanato; D. Fabris; M. Lunardon; S. Moretto; G. Nebbia; S. Pesente; G. Viesti

    2011-01-01

    Non-destructive assay of parcels using a tagged 252Cf source and time of flight technique was studied.The method of material recognition was achieved by measuring simultaneously the transmission of neutron and gamma ray to determine the average atomic number.The automatic tomography was realized with the movement of motors and autostart of the digital acquisition system.With the calibration of the detectors, the average atomic number for each pixel of the sample was determined which allows one to recognize material with this method.%本文叙述了利用252Cf裂变中子源结合飞行时间技术对包裹进行无损检测的可行性研究,通过联合测量中子和伽玛射线的吸收谱确定样品的平均原子序数,完成被测材料的鉴定.实验采用自发裂变的252Cf中子源作为白中子源和伽马射线源,用塑料闪烁探测器探测中子和伽马射线.通过LabVIEW程序控制步进电机运动并整合获取的实验数据,实现了待测样品断层扫描数据采集工作的自动化.在对闪烁探测器进行能量和时间刻度后,对几种典型材料组成的样品进行实验分析,采集数据重建其分布图像,确认了用这项技术对材料无损检测的可行性.

  11. Bacterial community shift in the coastal Gulf of Mexico salt-marsh sediment microcosm in vitro following exposure to the Mississippi Canyon Block 252 oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-07-10

    In this study, we examined the responses by the indigenous bacterial communities in salt-marsh sediment microcosms in vitro following treatment with Mississippi Canyon Block 252 oil (MC252). Microcosms were constructed of sediment and seawater collected from Bayou La Batre located in coastal Alabama on the Gulf of Mexico. We used an amplicon pyrosequencing approach on microcosm sediment metagenome targeting the V3–V5 region of the 16S rRNA gene. Overall, we identified a shift in the bacterial community in three distinct groups. The first group was the early responders (orders Pseudomonadales and Oceanospirillales within class Gammaproteobacteria), which increased their relative abundance within 2 weeks and were maintained 3 weeks after oil treatment. The second group was identified as early, but transient responders (order Rhodobacterales within class Alphaproteobacteria; class Epsilonproteobacteria), which increased their population by 2 weeks, but returned to the basal level 3 weeks after oil treatment. The third group was the late responders (order Clostridiales within phylum Firmicutes; order Methylococcales within class Gammaproteobacteria; and phylum Tenericutes), which only increased 3 weeks after oil treatment. Furthermore, we identified oil-sensitive bacterial taxa (order Chromatiales within class Gammaproteobacteria; order Syntrophobacterales within class Deltaproteobacteria), which decreased in their population after 2 weeks of oil treatment. Detection of alkane (alkB), catechol (C2,3DO) and biphenyl (bph) biodegradation genes by PCR, particularly in oil-treated sediment metacommunity DNA, delineates proliferation of the hydrocarbon degrading bacterial community. Overall, the indigenous bacterial communities in our salt-marsh sediment in vitro microcosm study responded rapidly and shifted towards members of the taxonomic groups that are capable of surviving in an MC252 oil-contaminated environment.

  12. Deoxyribonucleic acid initiation mutation dnaB252 is suppressed by elevated dnaC+ gene dosage.

    OpenAIRE

    Sclafani, R A; Wechsler, J A

    1981-01-01

    The Escherichia coli dnaB252 allele is the only dnaB mutation which confers a deoxyribonucleic acid initiation-defective phenotype on the cell. The presence of a multicopy hybrid plasmid containing the dnaC+ gene in a dnaB252 strain completely suppressed the temperature-sensitive phenotype. It is suggested that at high temperature the dnaB252 protein has a lowered affinity for dnaC protein, and that the formation of a dnaB-dnaC complex is mandatory for initiation.

  13. Cf-252 based neutron radiography using real-time image processing system

    International Nuclear Information System (INIS)

    For compact Cf-252 based neutron radiography, a real-time image processing system by particle counting technique has been developed. The electronic imaging system consists of a supersensitive imaging camera, a real-time corrector, a real-time binary converter, a real-time calculator for centroid, a display monitor and a computer. Three types of accumulated NR image; ordinary, binary and centroid images, can be observed during a measurement. Accumulated NR images were taken by the centroid mode, the binary mode and ordinary mode using of Cf-252 neutron source and those images were compared. The centroid mode presented the sharpest image and its statistical characteristics followed the Poisson distribution, while the ordinary mode showed the smoothest image as the averaging effect by particle bright spots with distributed brightness was most dominant. (author)

  14. Dynamics of the tri-nuclear system at spontaneous fission of $^{252}$Cf

    CERN Document Server

    Tashkhodjaev, R B; Alpomeshev, E Kh

    2016-01-01

    To describe of dynamics of ternary fission of $^{252}$Cf an equation of motion of the tri-nuclear system is calculated. The fission of the $^{70}$Ni+$^{50}$Ca+$^{132}$Sn channel was chosen as one of the more probable channels of true ternary fission of $^{252}$Cf. The collinearity of ternary fission has been checked by analyzing results of the equation of motion. The results show that if initially all nuclei are placed collinearly (potential energy of this position is the smallest) and the component of the middle fragment's initial velocity which is perpendicular to this line, is zero then ternary fission is collinear, otherwise the non collinear ternary fission takes place.

  15. Parallel and optimized genetic Elman network for 252Cf source-driven verification system

    Institute of Scientific and Technical Information of China (English)

    冯鹏; 魏彪; 金晶

    2015-01-01

    The 252Cf source-driven verification system (SDVS) can recognize the enrichment of fissile material with the enrichment-sensitive autocorrelation functions of a detector signal in 252Cf source-driven noise-analysis (SDNA) measurements. We propose a parallel and optimized genetic Elman network (POGEN) to identify the enrich-ment of 235U based on the physical properties of the measured autocorrelation functions. Theoretical analysis and experimental results indicate that, for 4 different enrichment fissile materials, due to higher information utilization, more efficient network architecture, and optimized parameters, the POGEN-based algorithm can ob-tain identification results with higher recognition accuracy, compared to the integrated autocorrelation function (IAF) method.

  16. Microbial response to the MC252 Oil and Corexit 9500 in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Romy eChakraborty

    2012-10-01

    Full Text Available The Deepwater Horizon spill released over 4.1 million barrels of crude oil into the Gulf of Mexico. In an effort to mitigate large oil slicks, the dispersant Corexit 9500 was sprayed onto surface slicks and injected directly at the wellhead at water depth of 1,500 meters. Several research groups were involved in investigating the fate of the MC-252 oil using newly advanced molecular tools to elucidate microbial interactions with oil, gases and dispersant. Presented here is a comprehensive overview of the ecogenomics of microbial degradation of MC-252 oil and gases in the water column and shorelines and some insight into the fate of the dispersant Corexit 9500 that was added to aid in oil dispersion process. We also present data that show the dispersant was not toxic to the indigenous microbes at concentrations added, and several bacterial species were able to degrade the various components of Corexit 9500.

  17. State Waste Discharge Permit application for industrial discharge to land: 200 East Area W-252 streams

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    This document constitutes the WAC 173-216 State Waste Discharge Permit application for six W-252 liquid effluent streams at the Hanford Site. Appendices B through H correspond to Section B through H in the permit application form. Within each appendix, sections correspond directly to the respective questions on the application form. The appendices include: Product or service information; Plant operational characteristics; Water consumption and waterloss; Wastewater information; Stormwater; Other information; and Site assessment.

  18. Structure of spontaneous fission spectrum of 252Cf and its impact on neutron albedo experiments' simulation

    International Nuclear Information System (INIS)

    Aimed at the problem of the energy spectrum of spontaneous fission source, which was used in neutron albedo experiments, we selected two sets of 252Cf fission spectra, which were fitted by formulae and were universally accepted. And they were applied in neutron albedo experiments independently. Neutron fluence and fission rate on each detecting point were compared and analyzed. The results show that Watt spectrum agrees the experiment data better than that of Maxwell spectrum. (authors)

  19. Oxygen enhancement ratio (OER) and therapeutic gain factor (GF) for californium-252 at low dose rate

    International Nuclear Information System (INIS)

    The potential benefit of the introduction of californium-252 in interstitial and intracavitary therapy is related to the greater efficiency of its neutron emission against anoxic cancer cells. In that respect, the oxygen enhancement ratio (OER) of the 252Cf emission has been determined for a continuous low dose rate irradiation. The biological system is growth inhibition in Vicia faba bean roots. A new Vicia faba ''BelB'' strain has been used, which better tolerates long periods (up to about 10 hours) of anoxia. In a first series of experiments, for a 252Cf (Dsub(n+γ)) dose rate of 0.11 Gy.h-1, an OER of 1.4+-0.1 was observed (the γ contribution Dγ to the total absorbed dose Dsub(n+γ) was 0.35 at the position of the root tips). In a second series of experiments, in somewhat different geometrical conditions with a 252Cf (Dsub(n+γ)) dose rate of 0.13 Gy.h-1, an OER of 1.5+-0.1 was observed (Dγ/Dsub(n+γ)=0.42). The OER values observed for similar irradiation times, with iridium-192 γ-rays, were 2.3+-0.2 and 2.6+-0.1 respectively, which leads to therapeutic gain factors (GF) of 1.6 and 1.7 respectively. These GF values are slightly lower than those previously obtained (GF=1.8) on the same system, with d(50)-Be p(75)-Be and 15 MeV neutron beams

  20. Functional design criteria for Project W-252, Phase II Liquid Effluent Treatment and Disposal: Revision 1

    International Nuclear Information System (INIS)

    This document provides the functional design criteria required for the Phase 2 Liquid Effluent Treatment and Disposal Project, Project W-252. Project W-252 shall provide new facilities and existing facility modifications required to implement Best Available Technology/All Known, Available, and Reasonable Methods of Prevention, Control, and Treatment (BAT/AKART) for the 200 East Phase II Liquid Effluent Streams. The project will also provide a 200 East Area Phase II Effluent Collection System (PTECS) for connection to a disposal system for relevant effluent streams to which BAT/AKART has been applied. Liquid wastestreams generated in the 200 East Area are currently discharged to the soil column. Included in these wastestreams are cooling water, steam condensate, raw water, and sanitary wastewaters. It is the policy of the DOE that the use of soil columns to treat and retain radionuclides and nonradioactive contaminants be discontinued at the earliest practical time in favor of wastewater treatment and waste minimization. In 1989, the DOE entered into an interagency agreement with Ecology and EPA. This agreement is referred to as the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). Project W-252 is one of the projects required to achieve the milestones set forth in the Tri-Party Agreement. One of the milestones requires BAT/AKART implementation for Phase II streams by October 1997. This Functional Design Criteria (FDC) document provides the technical baseline required to initiate Project W-252 to meet the Tri-Party Agreement milestone for the application of BAT/AKART to the Phase II effluents

  1. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    International Nuclear Information System (INIS)

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for 252Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  2. 252Cf-based borehole logging system for in-situ assaying of uranium ore

    International Nuclear Information System (INIS)

    A 252Cf based borehole logging system for in-situ assaying of uranium ore has been designed and constructed, and preliminary tests of system operation have been performed. The system employs a delayed neutron activation analysis (DNAA) technique for which the downhole feasibility was demonstrated by Kerr--McGee. DNAA measures uranium directly, thereby circumventing the disequilibrium problems which are inherent to natural gamma ray logging. An improved DNAA technique has been implemented which utilizes a smaller 252Cf source and is more sensitive than the Kerr--McGee system. In particular, the size of the 252Cf source has been reduced by more than a factor of 10 with respect to the source employed by Kerr--McGee. Shielding for the 252Cf source has been designed for ease of operation while meeting occupational radiological safety requirements. The present system is vehicle mounted and includes the downhole sonde, logging winch with 1,000 meters of 4HO cable, data handling electronics, data recording and display equipment, and source shielding. The design of the system includes the following features: logging speeds from stationary to 8 meters/min with the capacity for determining 0.01% U3O8 concentration at 1.5 meters/min; uranium concentration readout independent of source intensity; auxiliary neutron measurement for accurate correlation of DNAA signal to actual U3O8 present; natural gamma ray detector for gauging disequilibrium; and short normal resistivity for lithology. The present system is a fully operational prototype. An extensive field calibration and evaluation program will begin shortly to uncover design problems and to allow simplification of the system for production logging. Commercially available units will reflect the operational experience gained from the testing program

  3. Advanced conceptual design report. Phase II. Liquid effluent treatment and disposal Project W-252

    International Nuclear Information System (INIS)

    This Advanced Conceptual Design Report (ACDR) provides a documented review and analysis of the Conceptual Design Report (CDR), WHC-SD-W252-CDR-001, June 30, 1993. The ACDR provides further design evaluation of the major design approaches and uncertainties identified in the original CDR. The ACDR will provide a firmer basis for the both the design approach and the associated planning for the performance of the Definitive Design phase of the project

  4. State Waste Discharge Permit application for industrial discharge to land: 200 East Area W-252 streams

    International Nuclear Information System (INIS)

    This document constitutes the WAC 173-216 State Waste Discharge Permit application for six W-252 liquid effluent streams at the Hanford Site. Appendices B through H correspond to Section B through H in the permit application form. Within each appendix, sections correspond directly to the respective questions on the application form. The appendices include: Product or service information; Plant operational characteristics; Water consumption and waterloss; Wastewater information; Stormwater; Other information; and Site assessment

  5. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    OpenAIRE

    Elango, Vijaikrishnah; Urbano, Marilany; Lemelle, Kendall R.; Pardue, John H.

    2014-01-01

    Unique oil:sand aggregates, termed surface residue balls (SRBs), were formed on coastal headland beaches along the northern Gulf of Mexico as emulsified MC252 crude oil mixed with sand following the Deepwater Horizon spill event. The objective of this study is to assess the biodegradation potential of crude oil components in these aggregates using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 19-month period on the supratid...

  6. Advanced conceptual design report. Phase II. Liquid effluent treatment and disposal Project W-252

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-31

    This Advanced Conceptual Design Report (ACDR) provides a documented review and analysis of the Conceptual Design Report (CDR), WHC-SD-W252-CDR-001, June 30, 1993. The ACDR provides further design evaluation of the major design approaches and uncertainties identified in the original CDR. The ACDR will provide a firmer basis for the both the design approach and the associated planning for the performance of the Definitive Design phase of the project.

  7. Burnout and gate rupture of power MOS transistors with fission fragments of 252Cf

    International Nuclear Information System (INIS)

    A study to determine the single event burnout (SEB) and single event gate rupture (SEGR) sensitivities of power MOSFET devices is carried out by exposure to fission fragments from 252Cf source. The test method, test results, a description of observed burnout current waveforms and a discussion of a possible failure mechanism are presented. The test results include the observed dependence upon applied drain or gate to source bias and effect of external capacitors and limited resistors

  8. Experiment research on single event burnout of power MOSFET devices with 252Cf source

    International Nuclear Information System (INIS)

    The method in simulation of radiation effect test by 252Cf source was introduced, and the single event burnout experiment was carried out. The research result indicates that power MOSFET devices should be operated at the lowest voltage range un- der the radiation environment in the space, and adding a resister to confine the current in the circuit is an effective reinforce to avoid single event burnout. (authors)

  9. Oil in the Gulf of Mexico after the capping of the BP/Deepwater Horizon Mississippi Canyon (MC-252) well.

    Science.gov (United States)

    Kolian, Steve R; Porter, Scott A; Sammarco, Paul W; Birkholz, Detlef; Cake, Edwin W; Subra, Wilma A

    2015-08-01

    Evidence of fresh oil from the BP/Deepwater Horizon Mississippi Canyon-252 (MC-252) well was found in the northern Gulf of Mexico up to 1 year and 10 months after it was capped on 15 July 2010. Offshore and coastal samples collected after capping displayed ratios of biomarkers matching those of MC-252 crude oil. Pre- and post-capping samples were compared. Little weathering had occurred, based on the abundance of low-molecular-weight (LMW) n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in the post-capping samples. The occurrence of fresh oil in offshore waters and coastal areas suggest that the MC-252 well continued to leak hydrocarbons into the Gulf of Mexico at least until 22 May 2012, the end of this study period. PMID:25874429

  10. A Young Eclipsing Binary and its Luminous Neighbors in the Embedded Star Cluster Sh 2-252E

    CERN Document Server

    Lester, Kathryn V; Guo, Zhao

    2016-01-01

    We present a photometric and light curve analysis of an eccentric eclipsing binary in the K2 Campaign 0 field that resides in Sh 2-252E, a young star cluster embedded in an H II region. We describe a spectroscopic investigation of the three brightest stars in the crowded aperture to identify which is the binary system. We find that none of these stars are components of the eclipsing binary system, which must be one of the fainter nearby stars. These bright cluster members all have remarkable spectra: Sh 2-252a (EPIC 202062176) is a B0.5 V star with razor sharp absorption lines, Sh 2-252b is a Herbig A0 star with disk-like emission lines, and Sh 2-252c is a pre-main sequence star with very red color.

  11. On the 252Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    Science.gov (United States)

    Ghassoun, J.; Merzouki, A.; El Morabiti, A.; Jehouani, A.

    2007-10-01

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by 252Cf fission and also the primary gamma rays emitted directly by the 252Cf source at the exit face of a compact system designed for the BNCT. The system consists of a 252Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system.

  12. On the {sup 252}Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Merzouki, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco); Remote Sensing and Geomatics of the Environnement Laboratory, Ottawa-Carleton Geoscience Centre, Marion Hall-140Louis Pasteur Ottawa, ON, KIN 6N5 (Canada); El Morabiti, A.; Jehouani, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)

    2007-10-15

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by {sup 252}Cf fission and also the primary gamma rays emitted directly by the {sup 252}Cf source at the exit face of a compact system designed for the BNCT. The system consists of a {sup 252}Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system.

  13. On the 252Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    International Nuclear Information System (INIS)

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by 252Cf fission and also the primary gamma rays emitted directly by the 252Cf source at the exit face of a compact system designed for the BNCT. The system consists of a 252Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system

  14. 252Cf spectrum-averaged cross section for the 63Cu(n, p)63Ni reaction

    Science.gov (United States)

    Imamura, M.; Shibata, T.; Shibata, S.; Ohkubo, T.; Satoh, S.; Nogawa, N.

    1999-01-01

    The 63Ni produced by the 63Cu(n, p)63Ni reaction provides a unique measure to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bomb. In the similarity of the fission neutron spectrum of 252Cf to that of 235U, we have measured activation cross sections of the 63Cu(n, p)63Ni reaction averaged for the 252Cf fission spectrum.

  15. Measurement of 248cm/252Cf Spontaneous Prompt Fission Neutron Spectrum%248 Cm和252Cf自发裂变瞬发中子谱测量

    Institute of Scientific and Technical Information of China (English)

    包尚联; 刘文龙; 温琛林; 樊铁栓; 巴登柯夫; 马尧罗夫

    2001-01-01

    用飞行时间方法测量200keV-12MeV能区内248Cm和252Cf自发裂变瞬发中子谱,以国际原子能机构推荐的252Cf自发裂变瞬发中子谱为标准,可以免去探测器效率刻度的问题并消除系统误差,提高测量精度.实验用一个微型电离室作为裂变碎片探测器,两个芪晶体中子探测器测量中子及一套基于微机的CAMAC系统组成的飞行时间测量谱仪,在一个空旷的测量室内完成的.飞行距离分别为32,50和100cm,经过对数据的处理和分析给出了200keV-12MeV的中子能区内的实验数据.用Maxwell分布对实验数据进行拟合,得到的核温度为(1.401±0.006)MeV.%In order to treat the waste material of nuclear power and develop new type of clean nuclear power, it is necessary to measure the neutron data of long half life nuclei existed in the waste material. The prompt spontaneous neutron spectrum is one of the most important nuclear data for new type nuclear power facilities as well as for understanding the mechanism of fission neutron emission. The measurements of 248Cm/252Cf spontaneous prompt fission neutron spectrum in the neutron energy range from 200keV to 12MeV were performed by using TOF method. A micro-ionization chamber was used as fission fragment detector and stibene crystal as neutron detector. The flying paths of neutrons for the measurements were 30cm, 50cm and 100cm respectively. The spontaneous prompt fission neutron spectrum of 248Cm was fitted by the Maxwellian distribution and the temperature was determined as(1.401±0.006)MeV in the corresponding neutron energy range.

  16. 252Cf放射性同位素中子源辐照杀灭炭疽杆菌的理论研究%THEORY STUDY ON GERMICIDAL EFFICACY OF ANTHRAX SPORES BY RADIOISOTOPE Cf- 252 NEUTRON SOURCE

    Institute of Scientific and Technical Information of China (English)

    刘滨; 徐佳梁; 王凯; 胡文超

    2012-01-01

    目的 研究252Cf放射性同位素中子源辐照杀菌的可能性.方法 通过MCNP模拟计算方法,推算其所使用的模型,计算出252Cf中子辐射杀灭炭疽杆菌芽孢的辐照剂量和辐照时间.结果 经MCNP理论模拟研究,建立了MCNP模拟252Cf中子源产生的中子辐射消毒的模型,推演出使用石蜡作为反射材料可取得最好的结果.计算出用252Cf中子辐射杀灭炭疽杆菌芽孢的辐照剂量为1000 Gy,辐照时间为18 min.结论 利用252Cf中子辐射杀灭炭疽杆菌芽孢具有实际应用的可能性.%Objective To study the gerraicidal possibility of anthrax spores by radioisotope Cf - 252 neutron source. Method MCNP simulation calculation method was used to build the suitable model, calculate the radiation dose and radi-ation time required to sterilize the anthrax spores by the radioisotope Cf - 252 neutron source. Results The model was build to sterilize the anthrax spores by the radioisotope Cf - 252 neutron source. Simulation results showed that using paraffin as the reflecting materials in the model was the most effective in sterilization of the anthrax spores. The radiation dose calculated by the model was 1 000 Gy required to sterilize the anthrax spore by the radioisotope Cf - 252 neutron source, and the radiation time was about 18 min. Conclusion It is an effective and economic method to sterilize the anthrax spores by the radioisotope Cf - 252 neutron source in practical applications.

  17. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    Energy Technology Data Exchange (ETDEWEB)

    Cebulska-Wasilewska, A.; Rekas, K. [Institute of Nuclear Physics, Cracow (Poland); Kim, J.K. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of)

    1997-12-31

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  18. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    International Nuclear Information System (INIS)

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  19. Dosimetric analysis of BNCT - Boron Neutron Capture Therapy - coupled to 252Cf brachytherapy

    International Nuclear Information System (INIS)

    The incidence of brain tumors is increasing in world population; however, the treatments employed in this type of tumor have a high rate of failure and in some cases have been considered palliative, depending on histology and staging of tumor. Its necessary to achieve the control tumor dose without the spread irradiation cause damage in the brain, affecting patient neurological function. Stereotactic radiosurgery is a technique that achieves this; nevertheless, other techniques that can be used on the brain tumor control must be developed, in order to guarantee lower dose on health surroundings tissues other techniques must be developing. The 252Cf brachytherapy applied to brain tumors has already been suggested, showing promising results in comparison to photon source, since the active source is placed into the tumor, providing greater dose deposition, while more distant regions are spared. BNCT - Boron Neutron Capture Therapy - is another technique that is in developing to brain tumors control, showing theoretical superiority on the rules of conventional treatments, due to a selective irradiation of neoplasics cells, after the patient receives a borate compound infusion and be subjected to a epithermal neutrons beam. This work presents dosimetric studies of the coupling techniques: BNCT with 252Cf brachytherapy, conducted through computer simulation in MCNP5 code, using a precise and well discretized voxel model of human head, which was incorporated a representative Glioblastoma Multiform tumor. The dosimetric results from MCNP5 code were exported to SISCODES program, which generated isodose curves representing absorbed dose rate in the brain. Isodose curves, neutron fluency, and dose components from BNCT and 252Cf brachytherapy are presented in this paper. (author)

  20. Measurement of reflect neutron for 252Cf in cement cylinder by method of 235U fission

    International Nuclear Information System (INIS)

    The experiment theory of Research of neutron reflected coefficient for 252Cf in cement reflector was introduced. The fission rate of 235U with reflector, without reflector and with background was measured. The neutron reflected coefficient with cement reflector was concluded from fission rate and the reflected coefficient for different neutron source in the same experiment model was compared. The relation of reflected coefficient with angle was analyzed. The technology of solid track was researched and the best etch condition was explored. The trend of discharge count with coders thickness and etch thickness was gained. Efficiency for spark auto counters was measured and the technology of solid track was developed. (authors)

  1. Molecular vibrational states in the binary cold fission of $^{252}$Cf

    OpenAIRE

    Misicu, S.; Sandulescu, A.; Greiner, W.

    1998-01-01

    We predict a molecular vibrational state in the cold binary fission of $^{252}$Cf using a simple decay cluster model. The Hamiltonian of two even-even fragments in the pole-pole configuration is built in the same fashion as that for the dinuclear molecule formed in heavy-ions collisions. The interaction between the two fragments is described by the double-folding M3Y potential. The spectrum of the butterfly vibrations is derived and its dependence on fragments deformation and mass-assymetry i...

  2. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Mostacci, D.; Molinari, V. [Laboratorio di Ingegneria Nucleare di Montecuccolino, via dei Colli 16, 40136 Bologna (Italy); Jehouani, A. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)

    2010-02-15

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for {sup 252}Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  3. Effect of tissue inhomogeneities on dose distributions from Cf-252 brachytherapy source.

    Science.gov (United States)

    Ghassoun, J

    2013-01-01

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. PMID:23069196

  4. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D; Molinari, V; Jehouani, A

    2010-02-01

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for (252)Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect. PMID:19889549

  5. Rotational properties of $^{252, 253, 254}$No. Influence of pairing correlations

    OpenAIRE

    Duguet, T.; Bonche, P.; Heenen, P. -H.

    2000-01-01

    Rotational bands of $^{252, 253, 254}$No and the fission barriers of $^{254}$No at spin 0$\\hbar$ and 20$\\hbar$ are calculated with the Hartree-Fock-Bogolyubov theory and the Lipkin-Nogami approximate particle number projection. The SLy4 Skyrme force is used in the particle-hole channel. A zero-range force with and without density-dependence is used in the particle-particle channel. The experimental ground state deformation (${\\cal{Q}}_{20}$ = 32.8 b) is reproduced as well as the increase of t...

  6. Characterization of DNA helicase II from a uvrD252 mutant of Escherichia coli.

    OpenAIRE

    Washburn, B K; Kushner, S R

    1993-01-01

    The loss of DNA helicase II (UvrD) in Escherichia coli results in sensitivity to UV light and increased levels of spontaneous mutagenesis. While the effects of various uvrD alleles have been analyzed in vivo, the proteins produced by these alleles have not been examined in any detail. We have cloned one of these alleles, uvrD252, and determined the site of the mutation conferring the phenotype. In addition, the protein it encodes has been purified to homogeneity and characterized in vitro. Th...

  7. Analysis of molasses samples from various sugar industries in Maharashtra using 252Cf neutron source

    International Nuclear Information System (INIS)

    The molasses samples from various sugar industries in Maharashtra State have been analysed for their physico-chemical characteristics as well as elemental contents. The elements sodium, potassium, chlorine and manganese were determined using 252Cf neutron source by instrumental neutron activation analysis (INAA). Other parameters such as ash, moisture, total dissolved solids, pH as well as element Ca were estimated by usual conventional chemical methods. The percentage of various parameters varies from industry to industry and the concentration of elements is found in the order K > Ca > Cl > Na> Mn. (author). 3 refs., 2 tabs

  8. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    OpenAIRE

    JohnHPardue

    2014-01-01

    Biodegradation potential of MC252 in oil:sand aggregates, termed surface residue balls (SRBs), was examined using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 16-month period on the supratidal beach environment where reasonable control existed on the residence time of the aggregates on the beach surface. PAH and alkane concentration ratios were measured including PAH/C30-hopane, C2/C3 phenanthrenes, C2/C3 dibenzothiophenes...

  9. Role of energy cost in the yield of cold ternary fission of 252Cf

    Indian Academy of Sciences (India)

    P V Kunhikrishnan; K P Santhosh

    2013-01-01

    The energy costs in the cold ternary fission of 252Cf for various light charged particle emission are calculated by includingWong's correction for Coulomb potential. Energy cost is found to be higher in cold fission than in normal fission. It is found that energy cost always increases with decrease in experimental yield in all the light charged particle emissions. The higher ground state deformation of the fragments, the odd–even effect and the enhanced yield in the octupole region observed in cold fission are found to be consistent with the concept of energy cost.

  10. Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

    1976-01-01

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

  11. Neutron dose rate for {sup 252} Cf AT source in medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, L.; Balcazar, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico); Francois, J.L. [FI-UNAM, 04510 Mexico D.F. (Mexico)

    2006-07-01

    The AAPM TG-43 modified protocol was used for the calculation of the neutron dose rate of {sup 252}Cf sources for two tissue substitute materials, five normal tissues and six tumours. The {sup 252}Cf AT source model was simulated using the Monte Carlo MCNPX code in spherical geometry for the following factors: a) neutron air kerma strength conversion factor, b) dose rate constant, c) radial dose function, d) geometry factor, e) anisotropy function and f) neutron dose rate. The calculated dose rate in water at 1 cm and 90 degrees from the source long axis, using the Watt fission spectrum, was D{sub n}(r{sub 0}, {theta}{sub 0})= 1.9160 cGy/h-{mu}g. When this value is compared with Rivard et al. calculation using MCNP4B code, 1.8730 cGy/h-{mu}g, a difference of 2.30% is obtained. The results for the reference neutron dose rate in other media show how small variations in the elemental composition between the tissues and malignant tumours, produce variations in the neutron dose rate up to 12.25%. (Author)

  12. Young stellar population and ongoing star formation in the HII complex Sh2-252

    CERN Document Server

    Jose, Jessy; Samal, M R; Ojha, D K; Ogura, K; Kim, J S; Kobayashi, N; Goyal, A; Chauhan, N; Eswaraiah, C

    2013-01-01

    In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the cluster...

  13. Fragment angular momenta and descent dynamics in 252 Cf spontaneous fission

    International Nuclear Information System (INIS)

    Average angular momentum values of primary fission fragments as a function of neutron multiplicity and neutron-to-proton ratio were extracted for the first time for the Mo-Ba and Zr-Ce charge splittings of 252 Cf. The results are discussed in terms of the energy balance occurring at the scission point. For the first time we show that for large fragment elongation associated with larger numbers of evaporated neutrons (vtot ≥6), essentially only zero point bending oscillation takes places, i.e. T = 0 for this degree of freedom. For the major part of the fission events, with vtot = 2-5, the banding oscillation is excited to a temperature of 2-3 MeV. Such a high bending temperature implies that the coupling between the collective and internal degrees of freedom is weak at the descent of the even-even nucleus of 252 Cf to the scission point. The dipole oscillations occurring at the descent take away some 2.5 - 3.0 MeV from the release energy. A correlation between the fragment angular momentum and the mass asymmetry dependent yields of primary fragment pairs is reported. This correlation shows that the subtraction of 2.5 - 3.0 MeV from the total energy balance results in a remarkable reduction of the bending temperature. (authors)

  14. Multi-modal fission in collinear ternary cluster decay of 252Cf(sf, fff

    Directory of Open Access Journals (Sweden)

    W. von Oertzen

    2015-06-01

    Full Text Available We discuss the multiple decay modes of collinear fission in 252Cf(sf, fff, with three fragments as suggested by the potential energy surface (PES. Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of 252Cf(sf into three different masses (e.g. 132–140Sn, 52–48Ca, 68–72Ni, observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions of the JINR (Dubna the collinear cluster tripartition (CCT, is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay.

  15. [Radiation safety during work on the ANET-V therapeutic apparatus with 252Cf sources].

    Science.gov (United States)

    Chekhonadskiĭ, V N; Drygin, V N; Vaĭnberg, M Sh; Komar, V Ia; Elisiutin, G P

    1985-03-01

    The Soviet ANET-W intracavitary neutron therapy apparatus is charged with 252Cf sources, the total mass of the radionuclide being 2100 micrograms. The radiation exposure of the staff has been studied and the results presented. Possible emergency situations have been analysed, methods of their prevention and liquidation worked out. Induced radioactivity in the patient's body has been estimated. Radiation dose levels for the medical staff are 10-15 times lower for the ANET-W apparatus than those for 252Cf sources administered by the manual series system but 10 times higher than those for the AGAT-W gamma-apparatus. The design, blocking system and emergency reset of the sources provide for safe work on the ANET-W apparatus. During liquidation of an emergency situation irradiation of the staff does not exceed 0.3 of the annual maximum tolerance dose. The level of induced activity in the patient's body is insignificant as in 10.5 min it does not exceed background values. PMID:3982256

  16. GEANT4 and PHITS simulations of the shielding of neutrons from $^{252}$Cf source

    CERN Document Server

    Shin, Jae Won

    2014-01-01

    Neutron shielding simulations by using GEANT4 and PHITS code are performed. As a neutron source, $^{252}$Cf is considered and the energy distribution of the neutrons emitted from $^{252}$Cf is assumed the Watt fission spectrum. The neutron dose equivalent rates with and without the shield are estimated for shielding materials such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. For the neutron shielding simulations by using GEANT4, high precision (G4HP) model with G4NDL 4.2 based on ENDF-VII data are used. And for PHITS simulations, JENDL-4.0 library are used for the same purpose. It is found that differences between the shielding calculations by using GEANT4 with G4NDL 4.2 and PHITS with JENDL-4.0 library are not significant for all cases considered in this work. We investigate the accuracy of the neutron dose equivalent rates obtained from GEANT4 and PHITS by comparing our simulation results with experimental data and other values calculated earlier. Calculated neutron dose equivalent rates agree w...

  17. Investigation of forming mechanism of instantaneous neutron spectrum of 235U, 239Pu, 252Cf nuclei fission

    International Nuclear Information System (INIS)

    Formation mechanism of prompt neutrons spectrum during the fission of the 235U, 239Pu nuclei by thermal and fast neutrons and spontaneous fission of 252Cf is investigated. The formation procedure for prompt neutrons spectrum during the fission of nuclei as superposition of three partial evaporation Weisskopf spectra with the mean energy of neutrons 0.4, 2.06 and 2.8 MeV is proposed. Formation mechanism of the spectrum just as during the fission of the 235U, 239Pu nuclei by thermal and fast neutrons, so spontaneous fission of the 252Cf nuclei is identical

  18. 47 CFR 51.807 - Arbitration and mediation of agreements by the Commission pursuant to section 252(e)(5) of the Act.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Arbitration and mediation of agreements by the... Implementation of Section 252 of the Act § 51.807 Arbitration and mediation of agreements by the Commission... proceeding or matter. (c) In resolving, by arbitration under section 252(b) of the Act, any open issues...

  19. 48 CFR 252.209-7004 - Subcontracting with firms that are owned or controlled by the government of a terrorist country.

    Science.gov (United States)

    2010-10-01

    ... that are owned or controlled by the government of a terrorist country. 252.209-7004 Section 252.209....209-7004 Subcontracting with firms that are owned or controlled by the government of a terrorist... Controlled by the Government of a Terrorist County (DEC 2006) (a) Unless the Government determines that...

  20. On the use of a ({sup 252}Cf-{sup 3}He) assembly for landmine detection by the neutron back-scattering method

    Energy Technology Data Exchange (ETDEWEB)

    Elsheikh, N., E-mail: nassreldeen.elsheikh@yahoo.com [College of Applied and Industrial Science, Department of Physics, University of Juba, Khartoum, P.O. Box 12327/1 (Sudan); Viesti, G. [Dipartimento di Fisica ed Astronomia dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); ElAgib, I. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia); Habbani, F. [Faculty of Science, Physics Department, University of Khartoum, Khartoum, P.O. Box 321 (Sudan)

    2012-04-15

    Experiments were carried out to optimize the performance of the neutron back-scattering (NBS) technique in landmine detection using an assembly consisting of three different layers placed above a {sup 252}Cf neuron source, producing about 10{sup 4} s{sup -1}, in conjunction with a {sup 3}He detector. The assembly was optimized experimentally. The selected assembly configuration was then examined against different {sup 252}Cf stand-off distances and mine burial depths using dummy landmines. Furthermore, Monte Carlo simulations were performed to study the effect of the shield when a {sup 252}Cf source in the range 10{sup 4}-10{sup 7} s{sup -1} was employed, and to optimize the geometry for future prototypes. - Highlights: Black-Right-Pointing-Pointer A suitable shielded ({sup 252}Cf-{sup 3}He) assembly for landmine detection was developed. Black-Right-Pointing-Pointer Experimental tests and MCNP simulations were performed for a {sup 252}Cf of (10{sup 4}-10{sup 7})s{sup -1}. Black-Right-Pointing-Pointer Experimental and MCNP results for {sup 252}Cf of 10{sup 4}s{sup -1} supports the use of the shield. Black-Right-Pointing-Pointer MCNP Results recommends {sup 252}Cf of 10{sup 6}s{sup -1} for hand-held detection system. Black-Right-Pointing-Pointer MCNP Results recommends {sup 252}Cf of 10{sup 7}s{sup -1} for a robotic detection system.

  1. An algorithm for 252Cf-Source-Driven neutron signal denoising based on Compressive Sensing

    Institute of Scientific and Technical Information of China (English)

    李鹏程; 魏彪; 冯鹏; 何鹏; 米德伶

    2015-01-01

    As photoelectrically detected 252Cf-source-driven neutron signals always contain noise, a denoising algorithm is proposed based on compressive sensing for the noised neutron signal. In the algorithm, Empirical Mode Decomposition (EMD) is applied to decompose the noised neutron signal and then find out the noised Intrinsic Mode Function (IMF) automatically. Thus, we only need to use the basis pursuit denoising (BPDN) algorithm to denoise these IMFs. For this reason, the proposed algorithm can be called EMDCSDN (Empirical Mode Decomposition Compressive Sensing Denoising). In addition, five indicators are employed to evaluate the denoising effect. The results show that the EMDCSDN algorithm is more effective than the other denoising algorithms including BPDN. This study provides a new approach for signal denoising at the front-end.

  2. Molecular Collective Vibrations in the Ternary Neutronless Fission of $^{252}Cf$

    CERN Document Server

    Misicu, S; Sandulescu, A; Greiner, W

    1999-01-01

    Based on a recent experimental finding which may suggest the existence of a tri-nuclear molecular structure before the cold ternary fragmentation of $^{252}$Cf takes place, we solved the eigenvalue problem of a certain class of vibrations which are very likely to occur in these molecules. These oscillations are the result of the joined action of rotations of the heavier fragments and the transversal vibrations of the lighter spherical cluster with respect to the fission axis. In the calculation of the interaction between the heavier fragments we took into account higher multipole deformations, including the hexadecupole one, and introduced a repulsive nuclear part to insure the creation of a potential pocket in which a few molecular states can be accommodated. The possibility to observe the de-excitation of such states is discussed in connection with the molecular life-time.

  3. Fragment angular momentum and descent dynamics in 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    Fragment angular momenta as a function of neutron multiplicity were extracted for the first time for the Mo-Ba and Zr-Ce charge splits of 252Cf by studying prompt coincident γ-rays. The obtained primary fragment angular momenta do not continuously rise with the increase in the number of neutrons evaporated. In frame of the scission point bending oscillation model such regularity is explained due the decrease of the bending temperature. Adiabatic bending oscillations (T=0) are obtained at large (νtot>5) and small (νtot=0) scission point elongation. These oscillations are excited to the temperature of 2-3 MeV for the most probable scission configurations indicating a weak coupling between collective and internal degrees of freedom. A strong coupling between the collective bending and dipole oscillations was found

  4. Fragment angular momentum and descent dynamics in 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    Fragment angular momenta as a function of neutron multiplicity were extracted for the first time for the Mo-Ba and Zr-Ce charge splits of 252Cf by studying prompt coincident γ-rays. The obtained primary fragment angular momenta do not continuously rise with the increase in the number of neutrons evaporated. In frame of the scission point bending oscillation model such regularity is explained due the decrease of the bending temperature. Adiabatic bending oscillations (T=0) are obtained at large (νtot>5) and small (νtot=0) scission point elongation. These oscillations are excited to the temperature of 2 - 3 MeV for the most probable scission configurations indicating a weak coupling between collective and internal degrees of freedom. A strong coupling between the collective bending and dipole oscillations was found. copyright 1998 American Institute of Physics

  5. Beta decay of 252Cf on the way to scission from the exit point

    CERN Document Server

    Pomorski, K; Quentin, P

    2015-01-01

    Upon increasing significantly the nuclear elongation, the beta-decay energy grows. This paper investigates within a simple yet partly microscopic approach, the transition rate of the beta decay of the 252Cf nucleus on the way to scission from the exit point for a spontaneous fission process. A rather crude classical approximation is made for the corresponding damped collective motion assumed to be one dimensional. Given these assumptions, we only aim in this paper at providing the order of magnitudes of such a phenomenon. At each deformation the energy available for beta decay, is determined from such a dynamical treatment. Then, for a given elongation, transition rates for the allowed (Fermi) beta decay are calculated from pair correlated wave functions obtained within a macroscopic-microscopic approach and then integrated over the time corresponding to the whole descent from exit to scission. The results are presented as a function of the damping factor (inverse of the characteristic damping time) in use in...

  6. Gamma-ray studies of the spontaneous fission of 242Pu and 252Cr using gammasphere

    International Nuclear Information System (INIS)

    The authors report on the new results on 242Pu and 252Cf spontaneous fission gamma-rays with emphasis on the dependence of spin distributions on numbers of neutrons emitted. The analysis has concentrated first on extracting relative intensities of ground rotational transitions as a function of number of neutrons emitted. open-quotes Cold fissionclose quotes, or zero-neutron fission, is observed in a number of fissioning systems. Some isotopic series show a trend of decreasing fragment average spin with increasing numbers of neutrons emitted, contrary to the initial expectations of a simple quantal model based on neck thickness expected at scission. A simple open-quotes atomic orbitalclose quotes model plus Coulomb excitation is compared with the data. Preliminary results from an April 1994 run using 36 Ge detectors in Early Implementation of Gammasphere coupled with 4 neutron detectors and 1 X-ray detector are shown

  7. Effect of tissue Inhomogeneities on dose distributions from Cf-252 brachytherapy source

    International Nuclear Information System (INIS)

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. - Highlights: ► The effect of tissue inhomogeneities on dose distribution has been investigated. ► A comparison of our results with experimental data available in the literature is presented. ► Obtained results showed a significant change in neutron dose rate distributions.

  8. Biogeochemical characterization of MC252 oil:sand aggregates on a coastal headland beach.

    Science.gov (United States)

    Urbano, Marilany; Elango, Vijaikrishnah; Pardue, John H

    2013-12-15

    MC252 oil:sand aggregates, termed surface residue balls (SRBs), were sampled for physical, chemical and microbial characteristics from different tidal zones on a coastal headland beach in Louisiana, USA. Supratidal SRBs were smaller, had low moisture content, and salinities that were oil components were highest in the intertidal "oil mat" SRBs with C1- and C2-phenanthrenes, C2- and C3-dibenzothiophenes comprising the majority of the PAH concentrations. In the other SRB categories, PAHs and alkanes were depleted and profiles were skewed toward higher molecular weight compounds. Oxygen microelectrode measurements demonstrated that saturated O2 is present immediately after wetting, but O2 consumption in the interior of the aggregate occurs after a few days. Microbial populations varied with position on the beach but sequences similar to known PAH-degrading taxa (Mycobacterium sp. and Stenotrophomonas sp.) were observed.

  9. Investigation of the prompt-neutron spectrum for spontaneously-fissioning /sup 252/Cf

    Energy Technology Data Exchange (ETDEWEB)

    Poenitz, W.P.; Tamura, T.

    1982-01-01

    The prompt-fission-neutron spectrum of /sup 252/Cf was investigated. The spectrum was measured with Black Neutron Detectors which have a well known efficiency. Considerations of various issues in such measurements lead to an experiment in which a time-calibration pulser, a random pulser, the neutron detector time-of-flight spectrum, the pulse-shape-discriminator gamma time-of-flight spectrum, and the detector-response spectra were simultaneously recorded for the prompt-fission neutrons, transmission through carbon, and shadowbars in a total-cross-section-type measurement. Corrections and associated uncertainties were applied for a large variety of effects which may have been overlooked in many of the previously reported measurements. Preliminary results indicate deviations from a Maxwellian shape toward a Watt-spectrum shape. Agreement is good with the shape differences relative to a Maxwellian from the recent theoretical calculation by Madland and Nix, however, a lower average energy was found.

  10. Characteristics of the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators

    International Nuclear Information System (INIS)

    The authors established the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators at the Japan Nuclear Cycle Development Inst. (JNC), Tokai Works. The moderators are annular cylinders made of polymethyl methacrylate and steel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP-4B and the measurements by the Bonner multisphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields can provide the realistic neutron spectra similar to those encountered around the glove-boxes of the fabrication process of MOX (PuO2-UO2 mixed oxide) fuel. (authors)

  11. Characterization of core clinical phenotypes associated with recurrent proximal 15q25.2 microdeletions.

    Science.gov (United States)

    Burgess, Trent; Brown, Natasha J; Stark, Zornitza; Bruno, Damien L; Oertel, Ralph; Chong, Belinda; Calabro, Vanessa; Kornberg, Andrew; Sanderson, Christine; Kelly, Julian; Howell, Katherine B; Savarirayan, Ravi; Hinds, Rupert; Greenway, Anthea; Slater, Howard R; White, Susan M

    2014-01-01

    A recurrent proximal microdeletion at 15q25.2 with an approximate 1.5 megabase smallest region of overlap has recently been reported in seven patients and is proposed to be associated with congenital diaphragmatic hernia (CDH), mild to moderate cognitive deficit, and/or features consistent with Diamond-Blackfan anemia. We report on four further patients and define the core phenotypic features of individuals with this microdeletion to include mild to moderate developmental delay or intellectual disability, postnatal short stature, anemia, and cryptorchidism in males. CDH and structural organ malformations appear to be less frequent associations, as is venous thrombosis. There is no consistent facial dysmorphism. Features novel to our patient group include dextrocardia, obstructive sleep apnea, and cleft lip.

  12. Metronidazole in the treatment of cervical cancer using Cf-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Metronidazole was tested for its possible use in the Cf-252 brachytherapy of cervical cancer as a radiosensitizer and to deal with anaerobic pelvic infection. 15 patients were treated by only 14 were evaluable. All stages from stage IB-IVB were treated and complete local tumor regression was noted in all cases although it could take place very slowly. 5/14 (36%) are 1.5-3 year survivors but only among the patients with stage I-II disease. No unusual radio-enhancing action was observed but metronidazole appeared to be useful to treat the vaginal, cervix and uterine infections often associated with high stage disease and bulky, ulcerative or necrotic tumors

  13. Investigation of the prompt-neutron spectrum for spontaneously-fissioning 252Cf

    International Nuclear Information System (INIS)

    The prompt-fission-neutron spectrum of 252Cf was investigated. The spectrum was measured with Black Neutron Detectors which have a well known efficiency. Considerations of various issues in such measurements lead to an experiment in which a time-calibration pulser, a random pulser, the neutron detector time-of-flight spectrum, the pulse-shape-discriminator gamma time-of-flight spectrum, and the detector-response spectra were simultaneously recorded for the prompt-fission neutrons, transmission through carbon, and shadowbars in a total-cross-section-type measurement. Corrections and associated uncertainties were applied for a large variety of effects which may have been overlooked in many of the previously reported measurements. Preliminary results indicate deviations from a Maxwellian shape toward a Watt-spectrum shape. Agreement is good with the shape differences relative to a Maxwellian from the recent theoretical calculation by Madland and Nix, however, a lower average energy was found

  14. Clusters in true ternary fission in the 252Cf (Sf) reaction

    International Nuclear Information System (INIS)

    In the paper effect of the formation of clusters on production of the true ternary fission at simultaneous fission of 2'52Cf is investigated. Unlike conventional ternary fission with the emission of the alpha particle and binary fission, in true ternary fission reaction products are observed with the comparable masses and charges. By studying the potential energy surface calculated for the ternary system before splitting, charge and mass distributions of the nascent products at the spontaneous fission of 252Cf are estimated. Probabilities of the true ternary fission products will be greater where the potential energy surface has minima deeper. Results showed that the products of true ternary fission with magical numbers 20, 28, 50 and 82 for protons and neutrons are formed with a high probability. (authors)

  15. Variability of stalagmite-inferred Indian monsoon precipitation over the past 252,000 y.

    Science.gov (United States)

    Cai, Yanjun; Fung, Inez Y; Edwards, R Lawrence; An, Zhisheng; Cheng, Hai; Lee, Jung-Eun; Tan, Liangcheng; Shen, Chuan-Chou; Wang, Xianfeng; Day, Jesse A; Zhou, Weijian; Kelly, Megan J; Chiang, John C H

    2015-03-10

    A speleothem δ(18)O record from Xiaobailong cave in southwest China characterizes changes in summer monsoon precipitation in Northeastern India, the Himalayan foothills, Bangladesh, and northern Indochina over the last 252 kyr. This record is dominated by 23-kyr precessional cycles punctuated by prominent millennial-scale oscillations that are synchronous with Heinrich events in the North Atlantic. It also shows clear glacial-interglacial variations that are consistent with marine and other terrestrial proxies but are different from the cave records in East China. Corroborated by isotope-enabled global circulation modeling, we hypothesize that this disparity reflects differing changes in atmospheric circulation and moisture trajectories associated with climate forcing as well as with associated topographic changes during glacial periods, in particular redistribution of air mass above the growing ice sheets and the exposure of the "land bridge" in the Maritime continents in the western equatorial Pacific.

  16. Angular Momenta of Even-Even Fragments in the Neutronless Fission of $^{252}Cf$

    CERN Document Server

    Misicu, S; Ter-Akopian, G M; Greiner, W

    1999-01-01

    The recent advent of experimental techniques in which the dynamical characteristics of fission fragments are determined more accurately, prompted us to investigate the angular momentum acquired by fragments in a model which describes the cold(neutronless) fission of $^{252}$Cf as the decay of a giant nuclear molecule. The molecular configuration is a consequence of the interplay between the attractive nuclear part and the repulsive Coulomb+nuclear forces. The basic ideea of the present approach is to separate the radial(fission) modes describing the decay of the molecule from the modes associated to transversal vibrations(bending) of the fragments. The distance between the centers of the two fragments is fixed by the requirement that the energy released in the fission reaction $Q$, equals the sum of quantum zero-energies of radial and transversal modes and the total excitation energy $E^*$. Using a semiclassical coupled channel formalism we computed the additional angular momenta acquired by the fragments dur...

  17. Relative Yields of 149-153Pr in Spontaneous Fission of 252Cf

    Science.gov (United States)

    Eldridge, Jonathan; Wang, Enhong; Hwang, J. K.; Hamilton, Joe; Ramayya, A. V.; Luo, Y. X.; Rasmussen, J. O.; Zhu, S. J.; Liu, S. H.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.

    2013-10-01

    The relative yields of the fission partners of 149-153Pr, resulting from the spontaneous fission of 252Cf, were studied. This study was done by means of γ - γ - γ , and γ - γ - γ - γ coincidence data taken in 2000 by the multi-HPGe, Compton-suppressed, gamma detector array, Gammasphere, at Lawrence Berkeley National Lab. The coincidence data were analyzed by double- and triple-gating on transitions in 149-153Pr and obtaining the intensities of the 93-101Y transitions. For 150 , 151 , 152 , 153Pr the 3n channel was found to be the strongest. The 149Pr, however, was found to peak at the 4n channel. These results were used to verify the assignments of the level schemes of 151 , 152 , 153Pr. The data are found to be in agreement with Wahl's independent yield tables.

  18. 7 CFR 1726.252 - Prior approved contract modification related to liability for special and consequential damages.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Prior approved contract modification related to... Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES Modifications to RUS Standard Contract Forms § 1726.252 Prior...

  19. 48 CFR 252.225-7007 - Prohibition on Acquisition of United States Munitions List Items from Communist Chinese Military...

    Science.gov (United States)

    2010-10-01

    ... Regulation in 22 CFR Part 121. (b) Any supplies or services covered by the United States Munitions List that... of United States Munitions List Items from Communist Chinese Military Companies. 252.225-7007 Section... Chinese Military Companies. As prescribed in 225.1103(4), use the following clause: Prohibition...

  20. 8 CFR 252.3 - Great Lakes vessels and tugboats arriving in the United States from Canada; special procedures.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Great Lakes vessels and tugboats arriving... DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS LANDING OF ALIEN CREWMEN § 252.3 Great Lakes vessels... and tugboats. An immigration examination shall not be required of any crewman aboard a Great...

  1. 48 CFR 252.226-7001 - Utilization of Indian organizations, Indian-owned economic enterprises, and native Hawaiian small...

    Science.gov (United States)

    2010-10-01

    ... organizations, Indian-owned economic enterprises, and native Hawaiian small business concerns. 252.226-7001... Hawaiian small business concerns. As prescribed in 226.104, use the following clause: Utilization of Indian Organizations, Indian-Owned Economic Enterprises, and Native Hawaiian Small Business Concerns (SEP 2004)...

  2. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Science.gov (United States)

    2010-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Innovation Research (SBIR) Program. As prescribed in 227.7104(a), use the following clause: Rights in Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (JUN...

  3. 48 CFR 252.222-7001 - Right of first refusal of employment-Closure of military installations.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Right of first refusal of... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.222-7001 Right of first refusal...: Right of First Refusal of Employment—Closure of Military Installations (APR 1992) (a) The...

  4. PIXE, 252Cf-PDMS and radiochemistry applied for soil and vegetable analysis

    International Nuclear Information System (INIS)

    The aim of this work is to identify the elements present in vegetables and soils using PIXE (particle induced X-rays emission) and 252Cf-PDMS (252Cf plasma desorption mass spectrometry) techniques in order to estimate the possible influence of soil and agricultural techniques in the metal absorption by the vegetables. In this work, metal concentrations were evaluated in soil and vegetable samples from several regions, where different agricultural techniques were employed. Si, Zr, Ce, Th, Sc and Pb identified in the soil samples were not biologically available. Ga, Ge, As and Br identified in the tubercles indicate that spray pesticide used on the vegetable leaves was absorbed by them. 232Th and 238U present in the soil were not absorbed by the vegetables. The airborne particles from anthropogenic sources (as CFn, VCn) were absorbed by the vegetables. Compounds from mineral sources present in soil as V+, VCO3, HPO4, Cr+, CrOH+, Mn+, FeH+, Fe(OH)n and in the bioorganic compounds as N+, Ca(China)n+ and CnH+ were identified in vegetables. The metal absorption by the vegetables is not dependent of the metal concentration in soil. Different tubercles cultivated in the same soil show similar metal absorption. The exogenous contributions such as the elements present in water irrigation, pesticides, fertilizers and airborne particles deposited on leaves can be absorbed by vegetables. The absorption by the roots depends on the chemical compound of the elements. The use of pesticide sprays and air pollution can cause more contamination in the vegetables than in soil. The use of this methodology allows the identification of possible sources of metals in soils and in vegetables and the metal speciation

  5. Long repair replication patches are produced by the short-patch pathway in a uvrD252 (recL152) mutant of Escherichia coli K-12.

    OpenAIRE

    Rothman, R H; Fried, B

    1984-01-01

    The uvrD252 mutation leads to increased UV sensitivity, diminished dimer excision and host cell reactivation capacity, and an increase in the average patch size after repair replication. A recA56 uvrD252 double mutant was far more resistant to UV than was a recA56 uvrB5 double mutant. Its host cell reactivation capacity was identical to that of uvrD252 single mutant and was far greater than that of the uvrB5 single mutant. The strain showed no Weigle reactivation. From these results, we concl...

  6. Photoreactivation of ICR 2A frog cells after exposure to monochromatic ultraviolet radiation in the 252-313 nm range

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to photoreactivating light after treatment with monochromatic ultraviolet (UV) radiation in the 252-313nm range resulted in an increase in survival with similar photoreactivable sectors for each of the wavelengths tested. As photoreactivating enzyme is specific for the repair of pyrimidine dimers in DNA, these findings support the hypothesis that these are critical lesions responsible for killing of cells exposed to UV radiation in this wavelength range. The action spectra for cell killing and production of UV-endonuclease sensitive sites were similar to the DNA absorption spectrum though not identical. Because the number of endonuclease sensitive sites is a reflection of the yield of pyrimidine dimers, these data also suggest that the induction of dimers in DNA by UV radiation in the 252-313 nm range is the principle event leading to cell death. (author)

  7. Radioactive Beams from 252CF Fission Using a Gas Catcher and an ECR Charge Breeder at ATLAS

    CERN Document Server

    Pardo, Richard C; Hecht, Adam; Moore, Eugene F; Savard, Guy

    2005-01-01

    An upgrade to the radioactive beam capability of the ATLAS facility has been proposed using 252Cf fission fragments thermalized and collected into a low-energy particle beam using a helium gas catcher. In order to reaccelerate these beams an existing ATLAS ECR ion source will be reconfigured as a charge breeder source. A 1Ci 252Cf source is expected to provide sufficient yield to deliver beams of up to ~106 far from stability ions per second on target. A facility description, the expected performance and the expected performance will be presented in this paper. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract W-31-109-ENG-38.

  8. A comparison of dosimetric parameters and dose distribution around CF -252 and IR-192 LDR Brachytherapy Sources

    International Nuclear Information System (INIS)

    Full text: The purpose of this work is the evaluation and comparison of the dose rate distributions around a 252Cf Applicator Tube (AT) and 192Ir LDR sources. The dosimetric parameters were determined for both sources according to the updated AAPM TG-43U1 protocol. The calculations were performed using the Monte Carlo N-particle MCNP code, version 5C. To validate the results of this study, they were compared to experimental and analytical dosimetric data available in the literature for similar source configurations. After validation, the Monte Carlo computer code was applied to investigate the difference between dose rate distributions around the two brachytherapy sources, with the purpose of comparing their efficiency in treatment. The data so obtained also provide further information about spatial dose distributions and are important for detailed treatment planning with 252 Cf or 192Ir LDR sources for interstitial and intracavitary therapy

  9. Absolute measurement of anti ν/sub p/ for 252Cf using the ORNL large liquid scintillator neutron detector

    International Nuclear Information System (INIS)

    The ORNL large liquid scintillator detector was used in a precise determination of anti ν/sub p/, the number of neutrons emitted promptly, for spontaneous fission of 252Cf. Measurements of the detector efficiency over a broad energy region were made by means of a proton-recoil technique employing the ORELA white neutron source. Monte Carlo calculation of the detector efficiency for a spectrum representative of 252Cf fission neutrons was calibrated with these elaborate measurements. The unusually flat response of the neutron detector resulted in elimination of several known sources of error. Experimental measurement was coupled with calculational methods to correct for other known errors. These measurements lead to an unusually small estimated uncertainty of 0.2% in the value obtained, anti ν/sub p/ = 3.773 +- 0.007

  10. Neutron dosimetry for low dose rate Cf-252 AT sources and adherence to recent clinical dosimetry protocol for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, M.J.; Wierzbicki, J.G.; Van den Heuvel, F. [Wayne State Univ., Detroit, MI (United States). Dept. of Radiation Oncology; Martin, R.C. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.

    1997-12-01

    In 1995, the American Association of Physicists in Medicine Task Group 43 (AAPM TG-43) published a protocol obsoleting all mixed-field radiation dosimetry for Cf-252. Recommendations for a new brachytherapy dosimetry formalism made by this Task Group favor quantification of source strength in terms of air kerma rather than apparent Curies or other radiation units. Additionally, representation of this dosimetry data in terms of radial dose functions, anisotropy functions, geometric factors, and dose rate constants are in an angular and radial (spherical) coordinate system as recommended, rather than the along-away dosimetry data (Cartesian coordinate system) currently available. This paper presents the initial results of calculated neutron dosimetry in a water phantom for a Cf-252 applicator tube (AT) type medical source soon available from Oak Ridge National Laboratory (ORNL).

  11. A Monte Carlo simulation and setup optimization of output efficiency to PGNAA thermal neutron using 252Cf neutrons

    Science.gov (United States)

    Zhang, Jin-Zhao; Tuo, Xian-Guo

    2014-07-01

    We present the design and optimization of a prompt γ-ray neutron activation analysis (PGNAA) thermal neutron output setup based on Monte Carlo simulations using MCNP5 computer code. In these simulations, the moderator materials, reflective materials, and structure of the PGNAA 252Cf neutrons of thermal neutron output setup are optimized. The simulation results reveal that the thin layer paraffin and the thick layer of heavy water moderating effect work best for the 252Cf neutron spectrum. Our new design shows a significantly improved performance of the thermal neutron flux and flux rate, that are increased by 3.02 times and 3.27 times, respectively, compared with the conventional neutron source design.

  12. Decoupling of uranium metal with borated plaster using 252Cf nose analysis methods

    International Nuclear Information System (INIS)

    The use of borated plaster to isolate uranium (93.2 wt % 235U) metal was studied in a series of subcritical experiments with uranium metal cylinders (7.0 in. diam, 2.0 in. thick) and slabs (approx.1.4 x approx.5.4 x approx.10.1 in. dimensions). In the cylindrical experiments, the thickness of borated plaster was varied up to 10 in. and the subcriticality measured using the 252Cf-source-driven neutron noise analysis method. In the experiments with the uranium slabs, an array of slabs 3 wide and 8 high was assembled in steps to demonstrate the subcriticality of this array with 3.75-in.-thick borated plaster as an isolating material between all uranium slabs. In the slab experiments, both noise analysis and source neutron multiplication measurements were performed. Before assembly of the slab array the presence of boron in the plaster was verified by neutron transmission and gamma-ray spectrometry measurements

  13. Regional heat loss in resting man during immersion in 25.2 degrees C water.

    Science.gov (United States)

    Wade, C E; Dacanay, S; Smith, R M

    1979-06-01

    Five male subjects having a wide range of relative body fat, 9.2-20.2%, were studied during total body immersion in water at 25.2 degrees C. The regional surface area of each subject was calculated from anthropometric data utilizing a segmental geometric model. Skin temperatures (Tsk) and regional skin heat loss were measured prior to and during 30 min immersion at 13 sites. During immersion, mean Tsk was 25.9 degrees C and remained significantly higher than the water temperature. A measurable temperature gradient for heat flow was observed from all body segments. Segimental temperature in water ranged from 26.7-25.4 degrees C, being warmest at the neck and coolest at the foot. Heat the flow per regional area was highest in the neck, 187 W/m2, and least at the foot, 12 W/m2. Heat flow from each body region was dependent on regional Tsk. Skinfold thickness was a minor factor in altering regional heat flow in the foot, hand, lower arm, upper arm, thigh, and calf; in the torso, neck, and head regions it was of major importance in detering heat loss.

  14. Structures of the neutron-rich nuclei observed in fission of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Ramayya, A. V.; Hamilton, J. H.; Goodin, C. J.; Brewer, N. T.; Hwang, J. K. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 USA and Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liu, S. H. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 USA and UNRIB/Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Stone, N. J. [Department of Physics, Oxford University, Oxford OX1 3PU (United Kingdom); Daniel, A. V. [Flerov Laboratory of Nuclear Reactions, JINR, Dubna (Russian Federation); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China)

    2014-08-14

    Analysis of high statistics triple coincidence fission γ data from {sup 252}Cf at Gammasphere including angular correlations yielded well-expanded high-spin level schemes with more complete and reliable spin/parity assignments for {sup 82}Ge, {sup 118,120,122}Cd and {sup 114,115}Rh. Both the quasi-particle/hole couplings and quasi-rotational degrees of freedom are implied to play roles in these Cd isotopes. Evidence for triaxial shapes and octupole components in the Cd isotopes is presented. These Cd isotopes may have triaxial deformations. High-spin level schemes of {sup 114,115}Rh have been established for the first time. The existence of a relatively large signature splitting and an yrare band shows typical features of a triaxially deformed nucleus. Possible excited deformed rotational bands are observed, for the first time, in {sup 82}Ge. From the multipole mixing ratio measurement, the ground state configurations of {sup 109,111}Ru, as well as excited states in {sup 103,107}Mo and {sup 111}Ru were determined.

  15. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

    International Nuclear Information System (INIS)

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55Mn (n.gamma)56 Mn, high concentration of manganese in the matrix and short half - life of 56Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56Fe(n,p)56Mn and 59 Co (n, α)56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  16. Regional heat loss in resting man during immersion in 25.2 degrees C water.

    Science.gov (United States)

    Wade, C E; Dacanay, S; Smith, R M

    1979-06-01

    Five male subjects having a wide range of relative body fat, 9.2-20.2%, were studied during total body immersion in water at 25.2 degrees C. The regional surface area of each subject was calculated from anthropometric data utilizing a segmental geometric model. Skin temperatures (Tsk) and regional skin heat loss were measured prior to and during 30 min immersion at 13 sites. During immersion, mean Tsk was 25.9 degrees C and remained significantly higher than the water temperature. A measurable temperature gradient for heat flow was observed from all body segments. Segimental temperature in water ranged from 26.7-25.4 degrees C, being warmest at the neck and coolest at the foot. Heat the flow per regional area was highest in the neck, 187 W/m2, and least at the foot, 12 W/m2. Heat flow from each body region was dependent on regional Tsk. Skinfold thickness was a minor factor in altering regional heat flow in the foot, hand, lower arm, upper arm, thigh, and calf; in the torso, neck, and head regions it was of major importance in detering heat loss. PMID:475707

  17. OER by survival time for Cf-252, low dose rate Cs-137 and acute Co-60 for LSA lymphoma

    International Nuclear Information System (INIS)

    RBE and OER were determined for LSA tumor by survival time assay. The RBEn of Cf vs. Cs-137 was 5.8 and the OER was ∼ 1.4 by experiments performed in vitro and assayed in vivo. When tumor was irradiated in an advanced state in the living mouse, the RBEn was determined to be 5.2 vs. Cs-137. The RBE for hypoxic tumor is larger than for the oxic tumor for Cf-252 neutron irradiation. (Auth.)

  18. New source moderator geometry to improve performance of 252Cf and 241Am Be source-based PGNAA setups

    Science.gov (United States)

    Naqvi, A. A.; Abdelmonem, M. S.; Al-Misned, Ghada; Al-Ghamdi, Hanan

    2006-06-01

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups.

  19. Research and experimental work at Groote Schuur Hospital and the University of Cape Town using californium-252 sources

    International Nuclear Information System (INIS)

    Experiments have been undertaken to determine the high-LET and low-LET components of the absorbed dose from neutron beams. This is achieved by measuring the fluxes of the high-LET and low-LET radiations in a tissue-equivalent phantom individually and simultaneously using a scintillation probe fitted with a pulse shape discriminator. This system was successfully used with a 22 MeV neutron beam from the T(d,n) reaction and has been employed with 252Cf sources. Results obtained in the low-energy ranges (up to 3 MeV) indicate that the electron counts exceed the high-LET counts by a factor of 2 to 3. These results are related to the absorbed dose. Calculations have also been undertaken to establish whether the Paterson-Parker system could be used for the design of 252Cf treatments and the optimum needle activities to yield the desired dose. Experiments are under way to determine the variation of RBE and OER for 252Cf radiations around the source. The inhibition of root growth in Vicia Faba is being used to determine any such effects. Dose rates comparable to that employed in interstitial radiotherapy are being aimed at. A study of dose fractionation effects is also being undertaken. (author)

  20. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    OpenAIRE

    Samia de Freitas Brandao; Tarcisio Passos Ribeiro de Campos

    2013-01-01

    Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted int...

  1. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment.

    Science.gov (United States)

    Elango, Vijaikrishnah; Urbano, Marilany; Lemelle, Kendall R; Pardue, John H

    2014-01-01

    Unique oil:sand aggregates, termed surface residue balls (SRBs), were formed on coastal headland beaches along the northern Gulf of Mexico as emulsified MC252 crude oil mixed with sand following the Deepwater Horizon spill event. The objective of this study is to assess the biodegradation potential of crude oil components in these aggregates using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 19-month period on the supratidal beach environment with reasonable control over and knowledge of the residence time of the aggregates on the beach surface. Polycyclic aromatic hydrocarbons (PAHs) and alkane concentration ratios were measured including PAH/C30-hopane, C2/C3 phenanthrenes, C2/C3 dibenzothiophenes and alkane/C30-hopane and demonstrated that biodegradation was occurring in SRBs in the supratidal. These biodegradation reactions occurred over time frames relevant to the coastal processes moving SRBs off the beach. In contrast, submerged oil mat samples from the intertidal did not demonstrate chemical changes consistent with biodegradation. Review and analysis of additional biogeochemical parameters suggested the existence of a moisture and nutrient-limited biodegradation regime on the supratidal beach environment. At this location, SRBs possess moisture contents oil mat samples in the intertidal, an oxygen and salinity-impacted regime is proposed that severely limits biodegradation of alkanes and PAHs in this environment. These results support the hypothesis that SRBs deposited at different locations on the beach have different biogeochemical characteristics (e.g., moisture, salinity, terminal electron acceptors, nutrient, and oil composition) due, in part, to their location on the landscape.

  2. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    Directory of Open Access Journals (Sweden)

    Vijaikrishnah eElango

    2014-04-01

    Full Text Available Biodegradation potential of MC252 in oil:sand aggregates, termed surface residue balls (SRBs, was examined using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 16-month period on the supratidal beach environment where reasonable control existed on the residence time of the aggregates on the beach surface. PAH and alkane concentration ratios were measured including PAH/C30-hopane, C2/C3 phenanthrenes, C2/C3 dibenzothiophenes and alkane/C30-hopane and demonstrated unequivocally that biodegradation was occurring in SRBs in the supratidal. These biodegradation reactions occurred over time frames relevant to the coastal processes moving SRBs off the beach. In contrast, submerged oil mat (SOM samples did not demonstrate chemical changes consistent with biodegradation. Review and analysis of additional biogeochemical parameters suggested the existence of a moisture and N-limited biodegradation regime on the supratidal beach environment. At this location, SRBs possess moisture contents < 2% and molar C:N ratios from 131-323, well outside of optimal values for biodegradation in the literature. Despite these limitations, biodegradation of PAHs and alkanes proceeded at relevant rates (2-8 year-1 due in part to the presence of degrading populations, i.e., Mycobacterium sp., adapted to these conditions. For SOM samples in the intertidal, an oxygen and salinity-impacted regime is proposed that severely limits biodegradation of alkanes and PAHs in this environment. These results support the hypothesis that SRBs deposited at different locations on the beach have different biogeochemical characteristics (e.g., moisture; salinity; terminal electron acceptors; nutrient; and oil composition due, in part, to their location on the landscape.

  3. 252例儿童急性化脓性中耳炎菌群分布及药敏结果%Discussion of 252 pediatric cases of acute otitis media and appropriate treatment

    Institute of Scientific and Technical Information of China (English)

    马天宝; 韩光辉; 刘燕

    2006-01-01

    目的分析儿童急性化脓性中耳炎菌群分布及药敏结果,寻找有效的抗生素进行治疗.方法对252例0-1 2岁(252耳)经临床诊断为急性化脓性中耳炎患儿的耳道分泌物及鼓膜穿孔前期经鼓膜刺激取分泌物进行细菌培养,同时对培养阳性菌株的种类及药物敏感试验结果进行统计.结果252份分泌物共分离出病原菌260株,总阳性率为95.9%,8例检出2种菌株.其中G+球菌188株(占72.3%);G杆菌19株(占23.5%);真菌11株(占4.2%).结论;G+球菌是本地区儿童急性化脓性中耳炎的主要致病菌,对青霉素及红霉素均有较高的耐药性.提示,临床用药不能仅凭经验,而应根据细菌培养结果和药敏结果用药,以获得理想疗效,减少转化为慢性病程的可能.

  4. Design for TO-252 Transistor's Automatic Test & Mark Handler%TO-252晶体管全自动测试/打标分选机设计

    Institute of Scientific and Technical Information of China (English)

    马利年; 李伟民

    2012-01-01

    In the article, operational principle and the design of software and hardware for the TO-252 transistor's automatic test & mark handler with vision inspection function are introduced in detail. In the design for the handler, We imported the test pusher to solve the problem that the electrical characteristics is tested mistakenly due to the ill contact between the short lead of TO-252 transistor and the finger contactor. In the production flow, we add vision inspection station after test station and mark station to inspect the mark and the dimension of transistor's leads, It is to avoid the accidents happen that the productions with bad vision go into the good productions. It is proved that the handler have the virtues of high automation, high speed and reliable running, easy operation, simple maintenance and high price performance ratio. The handler gets good score from customers.%文章对带有外观检验功能的TO-252晶体管全自动测试/打标分选机的工作原理、软件和硬件设计进行详细介绍。该设计中首次引入测试推管机构,以解决因TO-252管脚太短、产品管脚与金手指接触不良引起的产品电参数测试误测问题;同时,在生产流程中引入外观检验工位,对测试、打标后的产品打标内容和管脚外型尺寸进行自动检验,很好地避免了成品中出现外观不良的产品。实践证明,该机具有自动化程度高、运行高速可靠、操作安全方便、维护简单、性价比高等优点,客户使用后反映良好。

  5. 252Cf自发裂变谱形对中子反射实验数值模拟的影响%Structure of Spontaneous Fission Spectrum of 252Cf and Its Impact on Neutron Albedo Experiments' Simulation

    Institute of Scientific and Technical Information of China (English)

    毛孝勇; 王敏; 温中伟; 王玫

    2009-01-01

    针对裂变源中子反射实验中涉及到的中子源能谱问题,选取两套用公式拟合、被普遍认可的252Cf自发裂变能谱,分别将其应用于该类实验的数值模拟中.对实验测点的中子注量及裂变反应率进行了对比研究,结果表明,相对于Maxwell谱,Watt谱能更好地与实验结果符合.

  6. The legacy of Cf-252 operations at Savannah River Technology Center: Continuous releases of radioiodine to the atmosphere

    International Nuclear Information System (INIS)

    The iodine isotopes I-132, 1-133, I-134, and I-135, which have half-lives ranging from 53 minutes to 21 hours, are measured in the atmospheric effluent from the Savannah River Technology Center (SRTC) at the Savannah River Site (SRS) near Aiken, South Carolina. SRS is operated by Westinghouse Savannah River Company for the US Department of Energy (DOE). The isotopes' release rates range from 10 to 300 microcuries per week compared to the rate. The resulting annual dose from all iodine isotopes is minor; it comprises 0.01 percent of the total offsite dose due to atmospheric releases from SRS in 1990. Circumstantial evidence indicates the radioiodine originates from traces of unencapsulated Cf-252. The determination that spontaneous fission of Cf-252 is the source of the radioiodine has several ramifications. Radioactive fission-product isotopes of the noble gas elements krypton and xenon must also be released. Noble gases are more volatile and mobile than iodine. Also, the released iodine isotopes decay to xenon isotopes. The noble gases decay to non-gaseous elements that are transported along with radioiodine to the terrestrial environment by deposition from the SRTC plume. Only Sr-89 is believed to accumulate sufficiently in the environment to approach detectable levels. Given similar conditions in earlier years, releases of short-lived radioiodine have occurred undetected in routine monitoring since the early 1970s. Release rates 20 years ago would have been 200 times greater than current release rates. This report documents preliminary experiments conducted by SRTC and Environmental Monitoring Section (EMS) scientists. The release process and the environmental impact of fission products from Cf-252 should be thoroughly researched

  7. Detailed Study of the Angular Correlations in the Prompt Neutron Emission in Spontaneous Fission of 252Cf

    Science.gov (United States)

    Kopatch, Yu.; Chietera, A.; Stuttgé, L.; Gönnenwein, F.; Mutterer, M.; Gagarski, A.; Guseva, I.; Chernysheva, E.; Dorvaux, O.; Hambsch, F.-J.; Hanappe, F.; Mezentseva, Z.; Telezhnikov, S.

    An experiment has been performed at IPHC Strasbourg, aimed at the detailed investigation of angular correlations in the neutron emission from spontaneous fission of 252Cf. Fission fragments were measured by the angle-sensitive double ionization chamber CODIS while neutrons were detected by a set of 60 DEMON scintillator counters. The main aim of the experiment is the observation of the correlation between the fragment spins and neutron emission anisotropy. Preliminary results, based on the Monte-Carlo simulations, as well as the preliminary analysis of the experimental data are shown.

  8. Design of a 252Cf neutron assay system for evaluation at the Savannah River Plant fuel fabrication facility

    International Nuclear Information System (INIS)

    A nondestructive assay (NDA) unit will be evaluated at the Savannah River Plant (SRP) reactor fuel fabrication facility for measurement of a range of highly enriched uranium materials. The unit employs cyclic neutron interrogation with a Cf-252 neutron source followed by delayed-neutron counting to assay the U-235 content of fuel alloys with up to 2.4 kg U-235 per item in addition to scrap and waste with a lower U-235 content. The accuracy goal for the majority of the measurements is 1 to 3 percent

  9. Neutron monitor calibration with 241AmBe(α, n), 252Cf , 252Cf+D2O and 238PuBe(α, n) used in dose evaluation near Linac

    International Nuclear Information System (INIS)

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, 241AmBe (α, n), 252Cf (f, n) and 252Cf+D2O, and a 238PuBe(α, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (author)

  10. Identification of new neutron-rich rare-earth nuclei produced in /sup 252/Cf spontaneous fission

    CERN Document Server

    Greenwood, R C; Gehrke, R J; Meikrantz, D H

    1981-01-01

    A program of systematic study of the decay properties of neutron-rich rare-earth nuclei with 30 s252/Cf spontaneous fission, is currently underway using the Idaho ESOL (Elemental Separation On Line) Facility. The chemistry system used for the rare-earth elemental separations consists of two high-performance chromatography columns connected in series and coupled to the /sup 252 /Cf fission source via a helium gas-jet transport arrangement. The time delay for separation and initiation of gamma -ray counting with results which have been obtained to date with this system include the identification of a number of new neutron-rich rare-earth isotopes including /sup 155/Pm (t/sub 1/2/=48+or-4 s) and /sup 163/Gd (t/sub 1 /2/=68+or-3 s), in addition to 5.51 min /sup 158/Sm which was identified in an earlier series of experiments. (11 refs).

  11. Multi-modal fission in collinear ternary cluster decay of {sup 252}Cf(sf, fff)

    Energy Technology Data Exchange (ETDEWEB)

    Oertzen, W. von, E-mail: oertzen@helmholtz-berlin.de [Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Joint Institute for Nuclear Research, FLNR, 141980 Dubna (Russian Federation); Nasirov, A.K. [Joint Institute for Nuclear Research, FLNR, 141980 Dubna (Russian Federation); Institute of Nuclear Physics, 100214, Tashkent (Uzbekistan); Kyungpook National University, 702-701, Daegu (Korea, Republic of); Tashkhodjaev, R.B. [Institute of Nuclear Physics, 100214, Tashkent (Uzbekistan); Inha University in Tashkent, 100170, Tashkent (Uzbekistan)

    2015-06-30

    We discuss the multiple decay modes of collinear fission in {sup 252}Cf(sf, fff), with three fragments as suggested by the potential energy surface (PES). Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of {sup 252}Cf(sf) into three different masses (e.g. {sup 132–140}Sn, {sup 52–48}Ca, {sup 68–72}Ni), observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions) of the JINR (Dubna) the collinear cluster tripartition (CCT), is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay.

  12. A comparison of {sup 252}Cf and 14-MeV neutron excitation to identify chemical warfare agents by PGNAA

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, A.J.; Harlow, B.D.; Edwards, A.J.; Krebs, K.M.; Jones, J.L.; Yoon, W.; Zabriskie, J.M.; Dougan, A.D.

    2000-07-01

    Since 1992, Idaho National Engineering and Environmental Laboratory's portable isotopic neutron spectrometry (PINS) system has been widely used for the nondestructive assessment of munitions suspected to contain chemical warfare agents, such as the nerve agent sarin. PINS is a {sup 252}Cf-based prompt gamma-ray neutron activation analysis (PGNAA) system. The standard PINS system employs a partially moderated 5-{micro}g {sup 252}Cf source emitting 10{sup 7} n/s to excite the atomic nuclei inside the item under test. The chemical elements inside the item are revealed by their characteristic gamma-ray spectrum, measured by a high-resolution high-purity germanium gamma-ray spectrometer. The system computer then infers the fill compound or mixture from the elemental data extracted from the gamma-ray spectrum. Reliable PINS assessments can be completed in as little as 100 s for favorable cases such as white phosphorus smoke munitions, but normally, a 1000 to 3000 live-second counting interval is required. To improve PINS throughput when hundreds or more munitions must be assessed, they are evaluating the possible advantages of 14-MeV neutron excitation over their current radioisotopic source.

  13. Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis

    Science.gov (United States)

    Senftle, F.E.; Macy, R.J.; Mikesell, J.L.

    1979-01-01

    The fast- and thermal-neutron fluence rates from a 3.7 ??g 252Cf neutron source in a simulated borehole have been measured as a function of the source-to-detector distance using air, water, coal, iron ore-concrete mix, and dry sand as borehole media. Gamma-ray intensity measurements were made for specific spectral lines at low and high energies for the same range of source-to-detector distances in the iron ore-concrete mix and in coal. Integral gamma-ray counts across the entire spectrum were also made at each source-to-detector distance. From these data, the specific neutron-damage rate, and the critical count-rate criteria, we show that in an iron ore-concrete mix (low hydrogen concentration), 252Cf neutron sources of 2-40 ??g are suitable. The source size required for optimum gamma-ray sensitivity depends on the energy of the gamma ray being measured. In a hydrogeneous medium such as coal, similar measurements were made. The results show that sources from 2 to 20 ??g are suitable to obtain the highest gamma-ray sensitivity, again depending on the energy of the gamma ray being measured. In a hydrogeneous medium, significant improvement in sensitivity can be achieved by using faster electronics; in iron ore, it cannot. ?? 1979 North-Holland Publishing Co.

  14. The emission probabilities of long range alpha particles from even-even 244-252Cm isotopes

    CERN Document Server

    Santhosh, K P; Priyanka, B

    2014-01-01

    The alpha accompanied cold ternary fission of even-even 244Cm, 246Cm, 248Cm, 250Cm and 252Cm isotopes have been studied by taking the interacting barrier as the sum of Coulomb and proximity potential with the fragments in equatorial configuration. The favorable fragment combinations are obtained from the cold reaction valley plot and by calculating the relative yield for the charge minimized fragments. In the alpha accompanied ternary fission of 244Cm isotope, the highest yield is found for the fragment combination 110Ru+4He+130Sn, which possess near doubly magic nuclei 130Sn. For the ternary fission of 246Cm, 248Cm, 250Cm and 252Cm isotopes with 4He as light charged particle, the highest yield is obtained for the fragment combination with doubly magic nuclei 132Sn as the heavier fragment. The emission probabilities and kinetic energies of long range alpha particle have been computed for the 242,244,246,248Cm isotopes and are found to be in good agreement with the experimental data. The relative yields for th...

  15. Measurement of the neutron activity of a 252Cf source relative to the average number of prompt neutrons emitted per fission for the spontaneous fission

    International Nuclear Information System (INIS)

    A method was developed for measuring the absolute neutron activity of a large 252Cf source. The neutron counting assembly is composed of eight BF3 counters mounted in a large tank filled with water which is used as a moderator. The detection efficiency is determined using a low activity 252Cf source. The method is based on the identification of every fission event, followed by the counting of the fission neutrons detected by the BF3 counters during a time interval equal to the maximum neutron lifetime in the moderator. The efficiency is thus obtained relative to the average number of prompt neutrons emitted per 252Cf spontaneous fission which is commonly used as a standard. The measurement accuracy is estimated to be of the order of 1%

  16. The Software Design for252Cf Neutron Activation Fuel Rod 235U Enrichment Inspecting Equipment%252Cf中子活化核燃料棒235U富集度检测设备的软件设计

    Institute of Scientific and Technical Information of China (English)

    张雷; 刘明; 马金波

    2013-01-01

    It introduces the software design for 252Cf neutron activation fuel red235U enrichment inspecting equipment.It used multithread technique to control Advantech PCI-1780 counter/timer card,and collect γ-ray signal from the six-path detectors.Process and analyze the collected data can exactly check the actual 235U enrichment and abnormal pellets in the nuclear fuel rods.The software can measure the actual 235U enrichment and judge whether there are abnormal pellets in the nuclear fuel rods accurately,and send customizing messages to PLC which complete automatic sorting,at 6 m/min detection speed.Now the software is used on nondestructive test equipment in Nuclear Fuel Element Factory.%介绍了252Cf中子活化核燃料棒235U富集度检测设备的软件设计,该软件采用多线程技术控制研华PCI-1780采集卡定时采集六路探测器输出的经252Cf中子活化后235U裂变产物的γ射线信号,针对采集数据的特性,进行相应的处理和分析,可以检测出核燃料棒的实际235U富集度以及有无异常芯块.该软件经过实验验证在检测速度为6时,能够准确测量核燃料棒的实际235U富集度值并判断棒中是否混有异常芯块,同时向PLC发送相应信号实现自动分选.目前已应用在核燃料元件厂的核燃料棒235U富集度无损检测设备上.

  17. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources; Importancia del coeficiente de kerma de neutrones en la planeacion de tratamientos de Braquiterapia con fuentes de Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [ININ, 52045 Ocoyocac, Estado de Mexico (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, 09000 Mexico D.F. (Mexico); Francois L, J.L. [UNAM, 04500 Mexico D.F. (Mexico)]. e-mail: lpg@nuclear.inin.mx

    2006-07-01

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 10{sup 6} n/s-{mu}g and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for E{sub n} > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with E{sub n} > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of {sup 252}Cf, to optimize and to individualize the patients treatments. (Author)

  18. Characterization of pKP-M1144, a Novel ColE1-like plasmid encoding IMP-8, GES-5, and BEL-1 β-lactamases, from a Klebsiella pneumoniae sequence type 252 isolate

    NARCIS (Netherlands)

    Papagiannitsis, Costas C.; Dolejska, Monika; Izdebski, Radoslaw; Dobiasova, Hana; Studentova, Vendula; Esteves, Francisco J.; Derde, Lennie P G; Bonten, Marc J M; Hrabák, Jaroslav; Gniadkowski, Marek

    2015-01-01

    IMP-8 metallo-β-lactamase was identified in Klebsiella pneumoniae sequence type 252 (ST252), isolated in a Portuguese hospital in 2009. blaIMP-8 was the first gene cassette of a novel class 3 integron, In1144, also carrying the blaGES-5, blaBEL-1, and aacA4 cassettes

  19. Numerical Simulation of Gas Flow During Arcing Process for 252 kV Puffer Circuit Breakers%Numerical Simulation of Gas Flow During Arcing Process for 252 kV Puffer Circuit Breakers

    Institute of Scientific and Technical Information of China (English)

    吴军辉; 王小华; 马志瀛; 荣命哲; 闫静

    2011-01-01

    A numerical simulation model for 252 kV puffer circuit breaker is constructed, by using a proven commercial computational fluid dynamics (CFD) package, PHOENICS. The model takes into account the moving parts in the circuit breaker, turbulence enhanced momentum and energy transport, radiation transport. The arcing process in a SF6 puffer circuit breaker with two hollow contacts is simulated under different conditions, and the simulation results are verified with experimental results. Through simulation, the pressure, temperature and velocity in the arc quenching chamber can be obtained. The simulation model is also capable of predicting the influence of design parameters variations on breaker performance, and can thus help to reduce the number of short-circuit tests during the design stage.

  20. Monte Carlo simulation optimisation of zinc sulphide based fast-neutron detector for radiography using a 252Cf source

    Science.gov (United States)

    Meshkian, Mohsen

    2016-02-01

    Neutron radiography is rapidly extending as one of the methods for non-destructive screening of materials. There are various parameters to be studied for optimising imaging screens and image quality for different fast-neutron radiography systems. Herein, a Geant4 Monte Carlo simulation is employed to evaluate the response of a fast-neutron radiography system using a 252Cf neutron source. The neutron radiography system is comprised of a moderator as the neutron-to-proton converter with suspended silver-activated zinc sulphide (ZnS(Ag)) as the phosphor material. The neutron-induced protons deposit energy in the phosphor which consequently emits scintillation light. Further, radiographs are obtained by simulating the overall radiography system including source and sample. Two different standard samples are used to evaluate the quality of the radiographs.

  1. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Energy Technology Data Exchange (ETDEWEB)

    Seabury, E.H. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)]. E-mail: Edward.Seabury@inl.gov; Blackburn, B.W. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Chichester, D.L. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Wharton, C.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Caffrey, A.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)

    2007-08-15

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, {gamma}) and (n, n') gamma rays from these elements by each type of neutron source.

  2. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    International Nuclear Information System (INIS)

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n') gamma rays from these elements by each type of neutron source

  3. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Science.gov (United States)

    Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2007-08-01

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.

  4. Magnetic behavior of the oxide spinels: Li0.5Fe2.5-2AlCrO4

    Indian Academy of Sciences (India)

    U N Trivedi; K B Modi; H H Joshi

    2002-05-01

    In order to study the effect of substitution of Fe3+ by Al3+ and Cr3+ in Li0.5Fe2.5O4 on its structural and magnetic properties, the spinel system Li0.5AlCrFe2.5-2O4 ( = 0.0, 0.2, 0.4, 0.5, 0.6 and 0.8) has been characterized by X-ray diffraction, high field magnetization, low field ac susceptibility and 57Fe Mössbauer spectroscopy. Contrary to the earlier reports, about 50% of Al3+ is found to occupy the tetrahedral sites. The system exhibits canted spin structure and a central paramagnetic doublet was found superimposed on magnetic sextet in the Mössbauer spectra ( > 0.5).

  5. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Directory of Open Access Journals (Sweden)

    Samia de Freitas Brandao

    2013-07-01

    Full Text Available Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the I 1 and I 2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the I 1 and I 2 infiltration zones. Conclusion Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.

  6. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    International Nuclear Information System (INIS)

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the /1 and /2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the /1 and /2 infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  7. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Samia de Freitas, E-mail: samiabrandao@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-06-15

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively, on the healthy tissue, on the balloon periphery and on the /{sub 1} and /{sub 2} tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively on the healthy tissue, on the target tumor and on the /{sub 1} and /{sub 2} infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  8. Maximum Alpha to Minimum Fission Pulse Amplitude for a Parallel-Plate and Hemispherical Cf-252 Ion-Chamber Instrumented Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Oberer, R.B.

    2000-12-07

    In an instrumented Cf-252 neutron source, it is desirable to distinguish fission events which produce neutrons from alpha decay events. A comparison of the maximum amplitude of a pulse from an alpha decay with the minimum amplitude of a fission pulse shows that the hemispherical configuration of the ion chamber is superior to the parallel-plate ion chamber.

  9. Experimental research on specific activity of 24Na using Chinese reference man phantom irradiated by 252Cf neutrons source

    International Nuclear Information System (INIS)

    Objective: To investigate the specific activity of '24Na per unit neutron fluence, AB/Φ,in blood produced for Chinese reference man irradiated by 252Cf neutron source,and to analyze the effects of scattering neutrons from ground,wall,and ceiling in irradiation site on it.Methods: A 252Cf neutron source of 3×108 n/s and the anthropomorphic phantom were used for experiments. The phantom was made from 4 mm thick of outer covering by perspex and the liquid tissue-equivalent substitute in it. The data of phantom dimensions fit into Chinese reference man.The weight ratios of H, N, O and C in substitute equal from source to long axis of phantom were 1.1, 2.1, 3.1 and 4.1 m, respectively. Both the neutron source and the position of xiphisternum of the phantom were 1.6 m above the floor. Results: The average specific activity of 24Na per unit neutron fluence was related to the irradiation-distances, d, and its maximum value, AB/ΦM, deduced by experimental data was about 1.85×10-7 Bq·cm2·g-1. Conclusions: The AB/ΦM corresponds to that of phantom irradiated by plane-parallel beams, and the value is about more 3% than that by BOMAB phantom reported in literature. It has shown that floor-(wall-)scattered neutrons in irradiation site have significant contribution to the specific activity of 24Na, but they contributed relatively little to the induced neutron doses. Consequently,using the specific activity of 24Na for assessing accidental neutron doses received by an individual, the contribution of scattered neutrons in accident site will lead dose to be overestimated, and need to be correct. (authors)

  10. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

    Energy Technology Data Exchange (ETDEWEB)

    Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: ce_delgado89@hotmail.com [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)

    2015-10-15

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  11. Radiological Characterization Technical Report on Californium-252 Sealed Source Transuranic Debris Waste for the Off-Site Source Recovery Project at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-04-24

    This document describes the development and approach for the radiological characterization of Cf-252 sealed sources for shipment to the Waste Isolation Pilot Plant. The report combines information on the nuclear material content of each individual source (mass or activity and date of manufacture) with information and data on the radionuclide distributions within the originating nuclear material. This approach allows for complete and accurate characterization of the waste container without the need to take additional measurements. The radionuclide uncertainties, developed from acceptable knowledge (AK) information regarding the source material, are applied to the summed activities in the drum. The AK information used in the characterization of Cf-252 sealed sources has been qualified by the peer review process, which has been reviewed and accepted by the Environmental Protection Agency.

  12. Gamma-ray multiplicity measurement of the spontaneous fission of {sup 252}Cf in a segmented HPGe/BGO detector array

    Energy Technology Data Exchange (ETDEWEB)

    Bleuel, D.L., E-mail: bleuel1@llnl.go [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Bernstein, L.A.; Burke, J.T. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Gibelin, J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Heffner, M.D. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Mintz, J. [Nuclear Engineering Department, University of California, Berkeley, CA 94720 (United States); Norman, E.B. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Nuclear Engineering Department, University of California, Berkeley, CA 94720 (United States); Phair, L. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Scielzo, N.D.; Sheets, S.A.; Snyderman, N.J.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Wiedeking, M. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2010-12-21

    Coincident {gamma} rays from a {sup 252}Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1{mu}Ci{sup 252}Cf source to cover a large solid angle for {gamma}-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt {gamma} rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a {gamma}-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

  13. A cumulative analysis of odontogenic cysts from major dental institutions of Bangalore city: A study of 252 cases

    Directory of Open Access Journals (Sweden)

    Prashanth Ramachandra

    2011-01-01

    Full Text Available Background: The objective of this study was to perform a cumulative analysis of odontogenic cysts obtained from the data of major dental institutions of Bangalore city, as well as to evaluate their distribution during a 5-year period and compare the results with other international studies. Materials and Methods: Data for the study were obtained from the reports of patients diagnosed with odontogenic cysts between 2005 and 2010 from different dental institutions of Bangalore. Case records of patients that fit the histological classification of the World Health Organization (WHO (2005 were included in the study and the following variables were analyzed: age, gender, anatomic location, and histological type. Results: In a total of 252 cyst specimens diagnosed, 79.76% were odontogenic cysts and 20.24% were nonodontogenic cysts. Among the odontogenic cysts most frequent lesions were radicular cysts (50.25%, followed by keratocysts (27.36% and dentigerous cysts (22.39%. Conclusions: Our study provides a cumulative data of odontogenic cysts in the population of Bangalore city. The results of our study showed a similar frequency of odontogenic cysts as compared to other populations of the world, with radicular cyst being identified as the most frequent odontogenic cyst. Keratocyst was the second most common cyst followed by dentigerous cyst.

  14. Improved calculation of the prompt fission neutron spectrum from the spontaneous fission of /sup 252/Cf: Preliminary results

    International Nuclear Information System (INIS)

    An improved calculation is presented for the prompt fission neutron spectrum N(E) from the spontaneous fission of /sup 252/Cf. In this calculation the fission-spectrum model of Madland and Nix is used, but with several improvements leading to a physically more accurate representation of the spectrum. Specifically, the contributions to N(E) from the entire fission-fragment mass and charge distributions will be calculated instead of calculating on the basis of a seven- point approximation to the peaks of these distributions as has been done in the past. Therefore, values of the energy release in fission, fission-fragment kinetic energy, and compound nucleus cross section for the inverse process will be considered on a point-by-point basis over the fragment yield distributions instead of considering averages of these quantities over the peaks of the distributions. Preliminary results will be presented and compared with a measurement, an earlier calculation, and a recent evaluation of the spectrum. 14 refs., 4 figs

  15. A comparative study on experimental and simulation responses of CR-39 to neutron spectra from a 252Cf source

    Directory of Open Access Journals (Sweden)

    Ghergherehchi Mitra

    2013-01-01

    Full Text Available A simulation of the interaction of neutrons emitted from a 252Cf source with a CR-39 detector is presented in this paper. Elastic and inelastic neutron interactions occur with the constituent materials of the CR-39 detector. Inelastic scatterings only consider (n, a and (n, p reactions. Fast neutrons tracks are, mainly, produced by recoil particle tracks in the plastic nuclear track detector as a result of the elastic scattering reaction of neutrons with the constituent materials of the solid-state nuclear track detectors, especially hydrogen nuclei. The energy of the neutron, incident position, direction, and type of interaction were sampled by the Monte Carlo method. The energy threshold, critical angle and scattering angle to the detector surface normal were the most important factors considered in our calculations. The energy deposited per neutron mass unit was calculated. The angular response was determined by both Monte Carlo simulation and experimental results. The number of visible proton tracks and energy deposited per neutron per visible track were calculated and simulated. The threshold energy of the recoil proton as a function of the thickness and incident proton angles was measured by the etchable range of protons at scattering angles, along with the shape and diameter of the track. Experimental and simulations result were in good agreement.

  16. Measurement of the energy spectrum of {sup 252}Cf fission fragments using nuclear track detectors and digital image processing

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Castano, V. M. [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Boulevard Juriquilla 3001, Santiago de Queretaro, 76230 Queretaro (Mexico); Gaso, I. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Mena, M.; Segovia, N. [UNAM, Instituto de Geofisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    The energy spectrum of {sup 252}Cf fission fragments was measured using nuclear track detectors and digital image analysis system. The detection material was fused silica glass. The detectors were chemically etched in an 8% HF solution. After experimenting with various etching time, it was found that the best resolution of the track diameter distribution was obtained after 30 minutes of etching. Both Gaussian and Lorentzian curves were fit to the track diameter distribution histograms and used to determine the basic parameters of the distribution of the light (N{sub L}) and heavy (N{sub H}) formed peaks and the minimum of the central valley (N{sub V}). Advantages of the method presented here include the fully-automated analysis process, the low cost of the nuclear track detectors and the simplicity of the nuclear track method. The distribution resolution obtained by this method is comparable with the resolution obtained by electronic analysis devices. The descriptive variables calculated were very close to those obtained by other methods based on the use of semiconductor detectors. (Author)

  17. Study on the effect of kidney transplantation on the health of the patients' offspring: a report on 252 Chinese children.

    Science.gov (United States)

    Xu, Longgen; Han, Peng; Liu, Yong; Wang, Hongwei; Yang, Yirong; Qiu, Feng; Peng, Wanling; Tang, Ligong; Fu, Jing; Zhu, Xiaofeng; Zhu, Youhua

    2014-01-01

    Even though the incidence of pregnancies in the female recipients is lower and also chronic renal disease in male patients is associated with impaired spermatogenesis, the health of the children born to these patients was not studied. In this report, we discuss information on the growth and development of offspring of 248 male and female kidney recipient patients. Physical and routine clinical measurements of the 252 offspring (129 male and 123 female) born to these transplantation patients were made along with the intelligence tests. In some of these children chest X-ray and immune indices were assessed. Among the recipients, 219 males fathered 223 children with an average birth weight of 3,255 ± 374 g and 29 female recipients gave birth to 29 children with an average birth weight of 2,923 ± 551. While most of these children were normal, we noticed a case of soft double toe, a case of short tongue tie, five cases of marginal mental retardation, three cases of proteinuria, six cases of microscopic hematuria, 15 cases of low hemoglobin, and 21 cases with recurrent respiratory tract infections. We conclude that kidney transplantation has no significant impact on the growth, development, health, and intelligence of the offspring born to recipients. PMID:23733673

  18. Determining the neutron spectrum of 241Am-Be and 252Cf sources using bonner sphere spectrometer

    Directory of Open Access Journals (Sweden)

    M.A Varshabi

    2016-06-01

    Full Text Available Bonner spheres system is one of the ways of measuring neutron energy distribution which is often applied in spectrometry and neutron dosimetry. This system includes a thermal neutron detector, being located in the center of several polyethylene spheres, and it is still workable due to the isotropic response of the system which in turn is derived from the spherical symmetry of moderators and the broad measurable range of the energy. In order to practically use this spectrometer, it is necessary to calibrate this system using standard neutron sources. This research aimed to determine the calibration factor of Bonner spheres spectrometry system and energy spectrum of two standard 241Am-Be and 252Cf sources in the atomic energy organization. Calibration and experimental measurement were done via the two standard sources. The response vector of each detector was derived by using MCNPX simulation code, based on the Monte Carlo method. The spectra unfolding of this system was performed through iterative method using the SPUNIT code done in software NSDUAZ6LiI and BUMS. 

  19. Variability of Indian summer monsoon over the past 252 kyr revealed by stalagmite record in Southwest China

    Science.gov (United States)

    Cai, Y.; Fung, I. Y.; Edwards, R.; An, Z.; Cheng, H.; Lee, J.

    2013-12-01

    Multiple proxies obtained from Arabian Sea sediments have revealed the variability of Indian summer Monsoon (ISM) on time scale of 100-105 years. These proxies mainly capture summertime winds over the Arabian Sea and our understanding of Indian summer monsoon precipitation variability; and the relationship between paleo-ISM and paleo East Asia summer monsoon (EASM) lacks precise articulation, however, due to the scarcity of high-resolution precipitation records spanning a glacial-interglacial cycle. Here, we present an absolutely-dated oxygen isotope record from stalagmites in Xiaobailong (XBL) cave, southwestern China, that documents the variability in local precipitation and the ISM for the past 252,000 years. This record is dominated by 23-kyr precessional cycles punctuated by prominent millennial-scale oscillations that are synchronous with Heinrich events in the North Atlantic. It also shows clear glacial-interglacial variations that are consistent with marine and other terrestrial proxies. The distinct glacial-interglacial range in XBL δ18O is larger than that of speleothem records from eastern China. Corroborated with results from an isotope-enabled global climate model, we hypothesize that these dissimilarities may reflect the different responses of ISM and EASM to changes in global circulation and moisture source, in particular those caused by glacial-interglacial sea-land configuration changes as manifested by notable coastline shifts in the Western Pacific and Maritime Continent.

  20. Effects of Exposure of Pink Shrimp, Farfantepenaeus duorarum, Larvae to Macondo Canyon 252 Crude Oil and the Corexit Dispersant

    Directory of Open Access Journals (Sweden)

    Susan Laramore

    2016-03-01

    Full Text Available The release of oil into the Gulf of Mexico (GOM during the Deepwater Horizon event coincided with the white and pink shrimp spawning season. To determine the potential impact on shrimp larvae a series of static acute (24–96 h toxicity studies with water accommodated fractions (WAFs of Macondo Canyon (MC 252 crude oil, the Corexit 9500A dispersant, and chemically enhanced WAFS (CEWAFs were conducted with nauplii, zoea, mysid, and postlarval Farfantepenaeus duorarum. Median lethal concentrations (LC50 were calculated and behavior responses (swimming, molting, light sensitivity evaluated. Impacts were life stage dependent with zoea being the most sensitive. Behavioral responses for all stages, except postlarvae, occurred at below LC50 values. Dispersants had the greatest negative impact while WAFs had the least. No short-term effects (survival, growth were noted for nauplii exposed to sub-lethal CEWAFs 39 days post-exposure. This study points to the importance of evaluating multiple life stages to assess population effects following contaminant exposure and further, that the use of dispersants as a method of oil removal increases oil toxicity.

  1. Power spectral density measurements with 252Cf for unreflected 17.77-cm-dia uranium (93.2 wt % 235U) metal cylinders

    International Nuclear Information System (INIS)

    The method of reactivity determination using noise analysis correlation measurements with 252Cf was used to determine the reactivity for subcritical 17.77-cm-dia uranium (93.2 wt percent 235U) metal cylinders with reactivities as low as 25 dollars. Far subcritical tests were performed with right circular cylinders of uranium metal for which the subcritical reactivity was known from other inverse kinetics and prompt neutron decay constant measurements

  2. Measurement of the neutron spectrum and ambient neutron dose rate equivalent from the small 252Cf source at 1 meter

    Energy Technology Data Exchange (ETDEWEB)

    Radev, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-07

    NASA Langley Research Center requested a measurement of the neutron spectral distribution and fluence from the 252Cf source (model NS-120, LLNL serial # 7001677, referred as the SMALL Cf source) and determination of the ambient neutron dose rate equivalent and kerma at 100 cm for the Radiation Budget Instrument Experiment (Rad-X). The dosimetric quantities should be based on the neutron spectrum and the current neutron-to-dose conversion coefficients.

  3. Residues 248-252 and 300-304 of the cardiac Na+/Ca2+ exchanger are involved in its regulation by phospholemman.

    Science.gov (United States)

    Zhang, Xue-Qian; Wang, JuFang; Song, Jianliang; Ji, Angi M; Chan, Tung O; Cheung, Joseph Y

    2011-10-01

    Using split cardiac Na(+)/Ca(2+) exchangers (NCX1), we previously demonstrated that phospholemman (PLM) regulates NCX1 by interacting with the proximal linker domain (residues 218-358) of the intracellular loop of NCX1. With the use of overlapping loop deletion mutants, interaction sites are localized to two regions spanning residues 238-270 and residues 300-328 of NCX1. In this study, we used alanine (Ala) linker scanning to pinpoint the residues in the proximal linker domain involved in regulation of NCX1 by PLM. Transfection of human embryonic kidney (HEK)293 cells with wild-type (WT) NCX1 or its Ala mutants but not empty vector resulted in NCX1 current (I(NaCa)). Coexpression of PLM with WT NCX1 inhibited I(NaCa). Mutating residues 248-252 (PASKT) or 300-304 (QKHPD) in WT NCX1 to Ala resulted in loss of inhibition of I(NaCa) by PLM. By contrast, inhibition of I(NaCa) by PLM was preserved when residues 238-242, 243-247, 253-257, 258-262, 263-267, 305-309, 310-314, 315-319, 320-324, or 325-329 were mutated to Ala. While mutating residue 301 to alanine completely abolished PLM inhibition, mutation of any single residue 250-252, 300, or 302-304 resulted in partial reduction in inhibition. Mutating residues 248-252 to Ala resulted in significantly weaker association with PLM. The NCX1-G503P mutant that lacks Ca(2+)-dependent activation retained its sensitivity to PLM. We conclude that residues 248-252 and 300-304 in the proximal linker domain of NCX1 were involved in its inhibition by PLM.

  4. Biological, chemical and other data collected aboard the THOMAS G. THOMPSON during cruise TN252 in the Coastal Waters of SE Alaska and North Pacific Ocean from 2010-07-26 to 2010-08-23 (NODC Accession 0104356)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104356 includes biological, chemical, optical, physical and underway data collected aboard the THOMAS G. THOMPSON during cruise TN252 in the Coastal...

  5. Optical and Near-infrared survey of the stellar contents associated with the star-forming Complex Sh2-252

    CERN Document Server

    Jose, Jessy; Ogura, K; Samal, M R; Ojha, D K; Bhatt, B C; Chauhan, N; Eswaraiah, C; Mito, H; Kobayashi, N; Yadav, R K; 10.1111/j.1365-2966.2012.21175.x

    2013-01-01

    We present the analyses of the stellar contents associated with the HII region Sh2-252 using UBVRI photometry, slit and slitless spectroscopy along with the NIR data from 2MASS for an area ~1 degree x 1 degree. We studied the sub-regions of Sh2-252 which includes four compact-HII (CHII) regions, namely A, B, C and E and two clusters NGC 2175s and Teutsch 136 (Teu 136). Of the fifteen spectroscopically observed bright stars, eight have been identified as massive members of spectral class earlier than B3. From the spectro-photometric analyses, we derived the average distance of the region as 2.4+/-0.2 kpc and the reddening of the massive members is found to vary between 0.35 to 2.1 mag. We found that NGC 2175s and Teu 136, located towards the eastern edge of the complex are the sub-clusters of Sh2-252. The stellar surface density distribution in K-band shows clustering associated with the regions A, C, E, NGC 2175s and Teu 136. We have also identified the candidate ionizing sources of the CHII regions. 61 H_alp...

  6. New source-moderator geometry to improve performance of 252Cf and 241Am-Be source-based PGNAA setups

    International Nuclear Information System (INIS)

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups

  7. New source-moderator geometry to improve performance of {sup 252}Cf and {sup 241}Am-Be source-based PGNAA setups

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Abdelmonem, M.S. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Misned, Ghada [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia); Al-Ghamdi, Hanan [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia)

    2006-06-15

    The gamma ray yield from a {sup 252}Cf and a {sup 241}Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the {sup 252}Cf and the {sup 241}Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a {sup 252}Cf and a {sup 241}Am-Be source-based PGNAA setups.

  8. 252例老年颅内肿瘤术后并发症的相关因素分析%Risk factors related to surgical complications in 252 elderly brain tumors

    Institute of Scientific and Technical Information of China (English)

    陈晓霖; 赵元立; 王硕; 叶迅; 赵继宗

    2013-01-01

    目的 分析与老年颅内肿瘤术后并发症相关的因素.方法 对北京天坛医院2005年1月至2007年12月252例手术治疗的老年颅内肿瘤相关资料进行回顾性研究.分析诸多临床因素与老年颅内肿瘤患者术后发生并发症的关系.应用SPSS 13.0软件进行单因素分析和多因素Logistic 回归分析.结果 单因素分析显示,术前患者卡氏评分(KPS)、肿瘤部位、术中出血量、麻醉时间、手术时间等与术后并发症的发生有关.多因素分析显示,术前患者KPS评分和肿瘤部位是术后并发症的主要影响因素.结论 术前KPS小于90分和肿瘤位于幕下等是术后并发症的主要影响因素.术中出血量、麻醉时间以及手术时间等因素也与术后并发症发生率有一定相关.而年龄、性别、肿瘤切除程度和术前美国麻醉师协会评分(ASA)等在本研究中显示不是术后并发症的主要影响因素.%Objective To investigate the factors associated with surgical complications.Methods A consecutive series of 252 surgeries performed from January 2005 to December 2007 were retrospectively analyzed.Age,sex,preoperative Karnofsky scale (KPS),American Society of Anesthesiologists (ASA) status,anatomic localization,extent of tumor resection,bleeding volume,anesthesia time and duration of the whole operation were evaluated.Results In multivariate analysis,only pre-operative KPS (P =0.001) and infratentorial tumors (P =0.019) showed the significant association with post-operative complications.Conclusion It shows that the preoperative KP5 and infratentorial location are the factors related to post-operative complications,whereas age,sex,ASA status,extent of tumor resection,the bleeding volume,anesthesia time and duration of the whole operation are not the risk factors.

  9. 252 Cases of Trace Elements in Peripheral Blood of Children and Correlation Analysis Results%252例儿童末梢血微量元素的检测结果及相关性分析

    Institute of Scientific and Technical Information of China (English)

    汪玥

    2012-01-01

      Objective In order to understand our city children aged 0 to 7,trace elements intake, clinical guidance, selective reasonable to add trace elements for children. Methods The children randomly selected pediatric patient health cards and children aged 0 to 7 252 cases, using Beijing Optoelectronic Technology Co,Ltd. Bo Hui innovative products BH5100T type five-channel atomic absorption spectrometry for zinc, iron, calcium, magnesium, copper 5 Detection of trace elements, and do statistical analysis. Results The children in our city there are different levels of trace element deficiency, including zinc, iron, calcium deficiency is the most serious, rates were 48.4%,50.8% and 47.6%, lack of magnesium and lack of copper lower incidences of 7.1 per cent, respectively with 9.5%;the results show that various micronutrient deficiencies in the gender difference was not statistically significant(P>0.05). Conclusion The results show that the intake of trace elements in our city children can not be optimistic,reasonable to add trace elements, can effectively prevent children from lack of trace elements, trace elements to prevent the abuse of excessive complement blindness.%  目的为了解我市0~7岁儿童微量元素摄入情况,指导临床,有选择性的给儿童合理补充微量元素.方法随机抽查儿保健卡和儿科门诊的0~7岁儿童252例,利用北京博晖创新光电技术股份有限公司生产的 BH5100T 型五通道原子吸收光谱仪进行锌、铁、钙、镁、铜五种微量元素的检测,并做统计学分析.结果我市儿童存在不同程度的微量元素缺乏情况,其中锌、铁、钙缺乏情况最为严重,发生率分别为48.4%、50.8%和47.6%,缺镁和缺铜的发生率较低,分别为7.1%和9.5%;分析发现各种微量元素缺乏在性别上差异无显著性(P>0.05).结论分析结果表明我市儿童的微量元素摄入不均衡,合理补充微量元素,可以有效的防止儿童微量元

  10. A Monte Carlo comparison of PGNAA system performance using 252Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Science.gov (United States)

    Naqvi, A. A.

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a 252Cf neutron and a 14-MeV neutron-based prompt γ-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a 252Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt γ-ray yields from the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt γ-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the 252Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  11. A Monte Carlo comparison of PGNAA system performance using {sup 252}Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a {sup 252}Cf neutron and a 14-MeV neutron-based prompt {gamma}-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a {sup 252}Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt {gamma}-ray yields from the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt {gamma}-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the {sup 252}Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  12. Simultaneous utilization of neutrons and γ-rays from 252Cf for condition measurement inside a blast furnace

    International Nuclear Information System (INIS)

    This paper describes the possibility of the realization of a multi-function radiation gauge to meet the requirement for more precise and stable control of a blast furnace. A basic concept of the gauge is to measure some quantities with simultaneous use of multi-radiations of neutrons and γ-rays, and to obtain multi-types of information on material flow and gas flow representing the conditions inside the blast furnace. The prototype gauge was assembled and examined which consisted of a radiation source of 252Cf (3.7 MBq), neutron moderator, lead shield, a bismuth germanate detector, stainless casing and a control unit. Laboratory experiments showed that the gauge could measure the quantities to be essential to estimate the blast furnace conditions. In practice, it clearly distinguished between iron ore and coke layers, and at the same time measured bulk density (1.0-1.5 g/cm3) of iron contained in iron ore by counting thermal neutron capture γ-rays (6.5-8.5 MeV) from iron. It also gave the information on material bulk density (0.5-2.5 g/cm3) by detecting Compton scattered γ-rays (1.0-1.5 MeV) from material, i.e. iron ore and coke. The relative accuracies in the measurement of iron bulk density and material bulk density were estimated to be within 1 and 4% in 300 s counting time, respectively. The possibility of the gauge has been proved and the on-line trial will be expected in the near future. (author)

  13. 252例先兆流产妇女妊娠结局及相关因素分析%Pregnancy Outcome and Related Factors in 252 Women with Threatened Miscarriage

    Institute of Scientific and Technical Information of China (English)

    谢瑞兰; 李斌; 张海青; 刘颖

    2006-01-01

    目的研究先兆流产不良妊娠结局的危险因素,为先兆流产的干预提供临床依据.方法随访252例先兆流产妇女的妊娠结局,通过病史询问和理化检查获得并登记影响妊娠结局的可能因素.结果20.23%先兆流产的患者最终发生自然流产,不良妊娠率为27.78%.在不良妊娠结局组中,高龄妊娠、低收入、污染接触职业、早期阴道流血、阴道多量流血、宫内大血肿的发生率显著高于良好妊娠结局组(P<0.05).流产史、夫妻关系不和、吸烟、酗酒、吸毒、流产家族史和配偶冶游史在两组之间的差异无显著性.Logistic回归分析:高龄妊娠、低收入、宫内大血肿及早期阴道流血进入回归方程.其中早期阴道流血OR值为2.542,P<0.01,其次,宫内大血肿OR值为2.379,P<0.05,具有统计学意义.高龄妊娠和低收入的OR值分别为1.764和1.930,但P>0.05,不具有统计学意义.结论先兆流产不良妊娠结局发生率较高,早期阴道流血、宫内大血肿是不良妊娠结局独立危险因素,高龄妊娠与低收入是可能的危险因素.

  14. Microarray analysis of DNA damage repair gene expression profiles in cervical cancer cells radioresistant to 252Cf neutron and X-rays

    Directory of Open Access Journals (Sweden)

    Yang Zhen-Zhou

    2010-02-01

    Full Text Available Abstract Background The aim of the study was to obtain stable radioresistant sub-lines from the human cervical cancer cell line HeLa by prolonged exposure to 252Cf neutron and X-rays. Radioresistance mechanisms were investigated in the resulting cells using microarray analysis of DNA damage repair genes. Methods HeLa cells were treated with fractionated 252Cf neutron and X-rays, with a cumulative dose of 75 Gy each, over 8 months, yielding the sub-lines HeLaNR and HeLaXR. Radioresistant characteristics were detected by clone formation assay, ultrastructural observations, cell doubling time, cell cycle distribution, and apoptosis assay. Gene expression patterns of the radioresistant sub-lines were studied through microarray analysis and verified by Western blotting and real-time PCR. Results The radioresistant sub-lines HeLaNR and HeLaXR were more radioresisitant to 252Cf neutron and X-rays than parental HeLa cells by detecting their radioresistant characteristics, respectively. Compared to HeLa cells, the expression of 24 genes was significantly altered by at least 2-fold in HeLaNR cells. Of these, 19 genes were up-regulated and 5 down-regulated. In HeLaXR cells, 41 genes were significantly altered by at least 2-fold; 38 genes were up-regulated and 3 down-regulated. Conclusions Chronic exposure of cells to ionizing radiation induces adaptive responses that enhance tolerance of ionizing radiation and allow investigations of cellular radioresistance mechanisms. The insights gained into the molecular mechanisms activated by these "radioresistance" genes will lead to new therapeutic targets for cervical cancer.

  15. Fine frequency tuning in sum-frequency generation of continuous-wave single-frequency coherent light at 252 nm with dual-wavelength enhancement.

    Science.gov (United States)

    Kumagai, Hiroshi

    2007-01-01

    Fine frequency tuning of the deep-ultraviolet single-mode coherent light at 252 nm was conducted through the PID feedback system automatically by changing the temperature of a beta-BaB(2)O(4) (BBO) crystal in a doubly resonant external cavity for the sum-frequency mixing of 373 and 780 nm light. The temperature-dependent frequency tuning rate is 19.3 MHzK(-1), which is sufficiently fine to realize the laser cooling of neutral silicon atoms because the natural width of the laser cooling transition is 28.8 MHz.

  16. Fine frequency tuning in sum-frequency generation of continuous-wave single-frequency coherent light at 252 nm with dual-wavelength enhancement.

    Science.gov (United States)

    Kumagai, Hiroshi

    2007-01-01

    Fine frequency tuning of the deep-ultraviolet single-mode coherent light at 252 nm was conducted through the PID feedback system automatically by changing the temperature of a beta-BaB(2)O(4) (BBO) crystal in a doubly resonant external cavity for the sum-frequency mixing of 373 and 780 nm light. The temperature-dependent frequency tuning rate is 19.3 MHzK(-1), which is sufficiently fine to realize the laser cooling of neutral silicon atoms because the natural width of the laser cooling transition is 28.8 MHz. PMID:17167584

  17. Calculations of the cross sections for synthesis of new {293-296}118 isotopes in {249-252}Cf(48Ca,xn) reactions

    CERN Document Server

    Cap, T; Kowal, M; Wilczynski, J

    2013-01-01

    A project of using a target consisting of the mixture of (249-252)Cf isotopes to be bombarded with the 48Ca beam, aimed to synthesize new isotopes of the heaviest known element Z = 118, is under way at the FLNR in Dubna. In the present work excitation functions for all the reactions: 249Cf(48Ca,xn)(297-x)118, 250Cf(48Ca,xn)(298-x)118, 251Cf(48Ca,xn)(299-x)118 and 252Cf(48Ca,xn)(300-x)118 have been calculated in the framework of the fusion-by-diffusion model, assuming fission barriers, ground-state masses and shell effects of the superheavy nuclei predicted by Kowal et al. Energy dependence of the effective cross sections for the synthesis of selected new isotopes: (293)118, (294)118, (295)118 and (296)118 is predicted for the particular isotopic composition of the Cf target prepared for the Dubna experiment.

  18. Equilibration in the reaction of 175 and 252 MeV /sup 20/Ne with /sup 197/Au. [Energy, element, and angular distributions

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, J.B.

    1978-06-01

    The highly inelastic nuclear reaction of /sup 197/Au with /sup 20/Ne at 175 and 252 MeV laboratory energies is studied. Energy-, elemental-, and angular- distributions for atomic numbers 5 to 30 (175 MeV) or 34 (252 MeV) are presented. The means and widths of the kinetic energy spectra for detected elements are compared with a theoretical calculation. The calculation postulates thermalization of the incident projectile kinetic energy, and includes one sha(e-vibrational degree of freedom and rigid rotation of the reaction complex. The effect of particle evaporation is considered. Good agreement of the expurimental mean energies with the theory is obtained. Poorer agreement of the kinetic energy widths with the theory may be due to a low-temperature quantal effect. The relative elemental yields are analyzed for their degree of equilibration, based on a model of diffusive nucleon exchange as described by the master equation. A similar degree of equilibration is observed for both reaction energies. The absolute elemental yields are reproduced qualitatively by employing an advanced diffusion code, coupled with calculation of the subsequent fission of heavy reaction products, including the compound nucleus. The angular distributions are analyzed with a simple model, to estimate the reaction lifetime of selected elements.

  19. Rapid Evolution to Blast Crisis Associated with a Q252H ABL1 Kinase Domain Mutation in e19a2 BCR-ABL1 Chronic Myeloid Leukaemia

    Directory of Open Access Journals (Sweden)

    Sarah L. McCarron

    2013-01-01

    Full Text Available A minority of chronic myeloid leukaemia (CML patients express variant transcripts of which the e19a2 BCR-ABL1 fusion is the most common. Instances of tyrosine kinase inhibitor (TKI resistance in e19a2 BCR-ABL1 CML patients have rarely been reported. A case of e19a2 BCR-ABL1 CML is described in whom imatinib resistance, associated with a Q252H ABL1 kinase domain mutation, became apparent soon after initiation of TKI therapy. The patient rapidly transformed to myeloid blast crisis (BC with considerable bone marrow fibrosis and no significant molecular response to a second generation TKI. The clinical course was complicated by comorbidities with the patient rapidly succumbing to advanced disease. This scenario of Q252H-associated TKI resistance with rapid BC transformation has not been previously documented in e19a2 BCR-ABL1 CML. This case highlights the considerable challenges remaining in the management of TKI-resistant BC CML, particularly in the elderly patient.

  20. HIVAP calculations for the synthesis of new isotopes of Z=116 and Z=118 through 250Cm(48Ca, xn) and 250-252Cf(48Ca, xn) reactions

    International Nuclear Information System (INIS)

    The production and study of superheavy elements is an important area of research in contemporary experimental nuclear physics. The heaviest element produced so far is Z=118 (one isotope with A=294) in the 48Ca + 249Cf reaction with a production cross-section of 0.5 pico barns. Here we propose 250Cm(48Ca, xn) and 250-252Cf(48Ca, xn) reactions for the synthesis of heavier isotopes of Z=116 and 118 with comparable theoretical production cross-sections. 250Cm, 250Cf, 251Cf and 252Cf are feasible targets with half lives of 8300, 13.1, 898 and 2.6 years respectively

  1. Inhibition of semiconservative DNA synthesis in ICR 2A frog cells exposed to monochromatic uv wavelengths (252-313 nm) and photoreactivating light

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to monochromatic uv wavelengths in the range 252-313 nm caused an inhibition of semiconservative DNA synthesis which was partially relieved in cells receiving a post irradiation treatment with photoreactivating light (>350 nm). Hence pyrimidine dimers acted as lesions blocking DNA synthesis in uv-irradiated cells based upon the specificity of photoreactivating enzyme for the light-dependent monomerization of dimers in DNA. Compared with the shorter wavelengths tested, however, this recovery of DNA synthesis was not as great in cells exposed to 302-nm radiation and was nearly absent in 313-nm-irradiated cells up to 12 hr after treatment. These results suggest that nondimer photoproducts also play an important role in causing DNA synthesis inhibition in cells exposed to wavelengths greater than 300 nm

  2. Shielding measures of photo-electrical receiving system of X-ray flash radiography in the surroundings of 252Cf radiation

    International Nuclear Information System (INIS)

    The integrative shielding system based on boron polyethylene, lead and lead glass is designed and esta blushed for the effective use of the photo-electrical receiving system of high energy X-ray flash radiography in the surroundings of 252Cf radiation. The theoretical analysis indicated that the influence of typical research levels of radiation relative to the noise of the charge-coupled device (CCD) camera was small when suitable shielding measures were used. The experiments based on this theoretical analysis indicate that the background gray scale noise due to the radiation in the CCD camera is less than the inherent background noise of the scientific-level CCD. The ratio of the white-dot noise that is created by radiation directly in the CCD chip is about 1 pixel/104 pixels, so the imaging quality can be ensured. (authors)

  3. Some characteristics of two azoreductase systems in rat liver. Relevance to the activity of 2-[4'-di(2"-bromopropyl)-aminophenylazo]benzoic acid (CB10-252), a compound possessing latent cytotoxic activity

    DEFF Research Database (Denmark)

    1975-01-01

    The system involved in the reduction of 2-[4'-di(2″-bromopropyl)aminophenylazo]benzoic acid (CB10-252), an agent designed for treating primary liver cell cancer, has been demonstrated to be localised mainly in the 108 000 × g supernatant fraction of rat liver homogenate. It is also present in other...... organs particularly in the spleen. DAB-azoreductase as shown previously is present almost entirely in the microsomal fraction and is found in high concentration only in liver. The pH maxima for CB10-252-azoreductase and DAB-azoreductase were 6.2 and 6.9, respectively. Methylred-azoreductase had...... properties in most respects similar to CBlO-252-azoreductase implying the importance of the 2'-car☐yl group in determining substrate specificity. The use of enzyme inhibitors and other additives showed that CB10-252 was not xanthine oxidase or dihydrofolate reductase. Its activity was not affected by carbon...

  4. Anatomy of a controversy: Application of the Langevin technique to the analysis of the Californium-252 Source-Driven Noise Analysis method for subcriticality determination

    International Nuclear Information System (INIS)

    The expressions for the power spectral density of the noise equivalent sources have been calculated explicitly for the (a) stochastic transport equation, (b) the one-speed transport equaton, (c) the one-speed P1 equations, (d) the one-speed diffusion equation and (e) the point kinetic equation. The stochastic nature of Fick's law in (d) has been emphasized. The Langevin technique has been applied at various levels of approximation to the interpretation of the Californium-252 Source-Driven Noise Analysis (CSDNA) experiment for determining the reactivity in subcritical media. The origin of the controversy surrounding this method has been explained. The foundations of the CSDNA method as a viable experimental technique to infer subcriticality from a measured ratio of power spectral densities of the outputs of two neutron detectors and a third external source detector has been examined by solving the one-speed stochastic diffusion equation for a point external Californium-252 source and two detectors in an infinite medium. The expression relating reactivity to the measured ratio of PSDs was found to depend implicitly on k itself. Through a numerical analysis fo this expression, the authors have demonstrated that for a colinear detector-source-detector configuration for neutron detectors far from the source, the expression for the subcritical multiplication factor becomes essentially insensitive to k, hence, demonstrating some possibility for the viability of this technique. However, under more realistic experimental conditions, i.e., for finite systems in which diffusion theroy is not applicable, the measurement of the subcritical multiplication factor from a single measured ratio of PSDs, without extensive transport calculations, remains doubtful

  5. Corrective Action Investigation Plan for Corrective Action Unit 252: Area 25 Engine Test Stand 1 Decontamination Pad, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, Nevada Operations Office

    1999-08-20

    This Corrective Action Investigation Plan contains the U.S. Department of Energy, Nevada Operations Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit 252 under the Federal Facility Agreement and Consent Order. Corrective Action Unit 252 consists of Corrective Action Site (CAS) 25-07-02, Engine Test Stand-1 (ETS-1) Decontamination Pad. Located in Area 25 at the intersection of Road H and Road K at the Nevada Test Site, ETS-1 was designed for use as a mobile radiation checkpoint and for vehicle decontamination. The CAS consists of a concrete decontamination pad with a drain, a gravel-filled sump, two concrete trailer pads, and utility boxes. Constructed in 1966, the ETS-1 facility was part of the Nuclear Rocket Development Station (NRDS) complex and used to test nuclear rockets. The ETS-1 Decontamination Pad and mobile radiation check point was built in 1968. The NRDS complex ceased primary operations in 1973. Based on site history, the focus of the field investigation activities will be to determine if any primary contaminants of potential concern (COPCs) (including radionuclides, total volatile organic compounds, total semivolatile organic compounds, total petroleum hydrocarbons as diesel-range organics, Resource Conservation and Recovery Act metals, total pesticides, and polychlorinated biphenyls) are present at this site. Vertical extent of migration of suspected vehicle decontamination effluent COPCs is expected to be less than 12 feet below ground surface. Lateral extent of migration of COPCs is expected to be limited to the sump area or near the northeast corner of the decontamination pad. Using a biased sampling approach, near-surface and subsurface sampling will be conducted at the suspected worst-case areas including the sump and soil near the northeast corner of the decontamination pad. The results of this field investigation will support a defensible e

  6. Conformational dynamics of cancer-associated MyD88-TIR domain mutant L252P (L265P) allosterically tilts the landscape toward homo-dimerization.

    Science.gov (United States)

    Zhan, Chendi; Qi, Ruxi; Wei, Guanghong; Guven-Maiorov, Emine; Nussinov, Ruth; Ma, Buyong

    2016-09-01

    MyD88 is an essential adaptor protein, which mediates the signaling of the toll-like and interleukin-1 receptors' superfamily. The MyD88 L252P (L265P) mutation has been identified in diffuse large B-cell lymphoma. The identification of this mutation has been a major advance in the diagnosis of patients with aldenstrom macroglobulinemia and related lymphoid neoplasms. Here we used computational methods to characterize the conformational effects of the mutation. Our molecular dynamics simulations revealed that the mutation allosterically quenched the global conformational dynamics of the toll/IL-1R (TIR) domain, and readjusted its salt bridges and dynamic community network. Specifically, the mutation changed the orientation and reduced the fluctuation of α-helix 3, possibly through eliminating/weakening ~8 salt bridges and enhancing the salt bridge D225-K258. Using the energy landscape of the TIR domains of MyD88, we identified two dynamic conformational basins, which correspond to the binding sites used in homo- and hetero-oligomerization, respectively. Our results indicate that the mutation stabilizes the core of the homo-dimer interface of the MyD88-TIR domain, and increases the population of homo-dimer-compatible conformational states in MyD88 family proteins. However, the dampened motion restricts its ability to heterodimerize with other TIR domains, thereby curtailing physiological signaling. In conclusion, the L252P both shifts the landscape toward homo-dimerization and restrains the dynamics of the MyD88-TIR domain, which disfavors its hetero-dimerization with other TIR domains. We further put these observations within the framework of MyD88-mediated cell signaling. PMID:27503954

  7. Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-09-10

    The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium,  Pseudoalteromonas,  Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.

  8. Biological Efficiency of Californium-252 Source Evaluated by Comet Assay, Classical Cytogenetics and FISH in Human Lymphocytes Irradiated without and with BSH Pretreatment

    International Nuclear Information System (INIS)

    Biological effectiveness of californium-252 source was evaluated after irradiations in vitro of normal or pre-treated with compound enriched in B-10 ion cells. Peripheral blood lymphocytes were used as a model for human cells. DNA and chromosomal damage were studied to compare biological effectiveness of irradiation. Human blood samples or isolated lymphocytes were irradiated with the isotopic source of 252Cf, at the Faculty of Physics and Nuclear Techniques at the University of Mining and Metallurgy (both neutron source and samples were placed in ''infinite'' polyethylene block). Chemical pretreatment with Na210B12H11SH (BSH) was performed to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Single cell gel electrophoresis also known as the Comet assay was done to investigate the DNA damage. Classical cytogenetic analysis was applied to assess the frequencies of unstable aberrations (dicentrics, rings and a centric fragments). To evaluate the frequencies of stable aberrations the fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 4 (14.3% of the whole genome) was performed. Linear (or close to linear) increase with radiation dose were observed for the DNA damage and aberration frequencies in lymphocytes both untreated or pre-treated with BSH. Levels of translocations evaluated for the whole genome were comparable with the frequencies of dicentrics and rings. No significant differences were detected due to radiation dose in the frequencies of sister chromatid exchanges (SCE) detected in the second mitosis. No statistically significant differences were observed in various biological end-points between normal or boron pre-treated cells. (author)

  9. Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252).

    Science.gov (United States)

    Koo, Hyunmin; Mojib, Nazia; Thacker, Robert W; Bej, Asim K

    2014-11-01

    The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium,  Pseudoalteromonas,  Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.

  10. UvrD and UvrD252 counteract RecQ, RecJ, and RecFOR in a rep mutant of Escherichia coli.

    Science.gov (United States)

    Lestini, Roxane; Michel, Bénédicte

    2008-09-01

    Rep and UvrD are two related Escherichia coli helicases, and inactivating both is lethal. Based on the observation that the synthetic lethality of rep and uvrD inactivation is suppressed in the absence of the recombination presynaptic proteins RecF, RecO, or RecR, it was proposed that UvrD is essential in the rep mutant to counteract a deleterious RecFOR-dependent RecA binding. We show here that the synthetic lethality of rep and uvrD mutations is also suppressed by recQ and recJ inactivation but not by rarA inactivation. Furthermore, it is independent of the action of UvrD in nucleotide excision repair and mismatch repair. These observations support the idea that UvrD counteracts a deleterious RecA binding to forks blocked in the rep mutant. An ATPase-deficient mutant of UvrD [uvrD(R284A)] is dominant negative in a rep mutant, but only in the presence of all RecQJFOR proteins, suggesting that the UvrD(R284A) mutant protein is deleterious when it counteracts one of these proteins. In contrast, the uvrD252 mutant (G30D), which exhibits a strongly decreased ATPase activity, is viable in a rep mutant, where it allows replication fork reversal. We conclude that the residual ATPase activity of UvrD252 prevents a negative effect on the viability of the rep mutant and allows UvrD to counteract the action of RecQ, RecJ, and RecFOR at forks blocked in the rep mutant. Models for the action of UvrD at blocked forks are proposed. PMID:18567657

  11. A fast neutron and dual-energy gamma-ray absorption method (NEUDEG) for investigating materials using a 252Cf source

    International Nuclear Information System (INIS)

    DEXA (dual-energy X-ray absorption) is widely used in airport scanners, industrial scanners and bone densitometers. DEXA determines the properties of materials by measuring the absorption differences of X-rays from a bremsstrahlung tube source with and without filtering. Filtering creates a beam with a higher mean energy, which causes lower material absorption. The absorption difference between measurements (those with a filter subtracted from those without a filter) is a positive number that increases with the effective atomic number of the material. In this paper, the concept of using a filter to create a dual beam and an absorption difference in materials is applied to radiation from a 252Cf source, called NEUDEG (neutron and dual-energy gamma absorption). NEUDEG includes absorptions for fast neutrons as well as the dual photon beams and thus an incentive for developing the method is that, unlike DEXA, it is inherently sensitive to the hydrogen content of materials. In this paper, a model for the absorption difference and absorption sum in NEUDEG is presented using the combined gamma ray and fast neutron mass attenuation coefficients. Absorption differences can be either positive or negative in NEUDEG, increasing with increases in the effective atomic number and decreasing with increases in the hydrogen content. Sample sets of absorption difference curves are calculated for materials with typical gamma-ray and fast neutron mass attenuation coefficients. The model, which uses tabulated mass attenuated coefficients, agrees with experimental data for porcelain tiles and polyethylene sheets. The effects of “beam hardening” are also investigated. - Highlights: • Creation of a dual neutron/gamma beam from 252Cf is described. • An absorption model is developed using mass attenuation coefficients. • A graphical method is used to show sample results from the model. • The model is successfully compared with experimental results. • The importance of

  12. Liver support therapy with molecular adsorbents recirculating system in liver failure:a summary of 252 cases from 14 centers in China

    Institute of Scientific and Technical Information of China (English)

    WANG Min-min; HU Xiao-bin; LUO Hong-tao; LIU Yi-he; WANG Wen-ya; CHEN Shi-jun; YE Qi-fa; YANG Yi-jun; CHEN Shi-bin; ZHOU Xin-min; GUO Li-min; ZHANG Yue-xin; DING Xiao-qiang

    2008-01-01

    Background A liver support therapy,named molecular adsorbents recirculating system (MARS),has been used for more than 700 liver failure patients in China.We made here a summary to evaluate the effects of MARS treatment in different applications with emphasis on hepatitis B virus (HBV) based liver failure.Methods This report analyzed data of 252 patients (mean age (44.9±12.7) years) in three groups:acute severe hepatitis (ASH),subacute severe hepatitis (SSH) and chronic severe hepatitis (CSH).The largest group was CSH (156 patients,61.9%),and 188 patients (74.6%,188/252) were infected with HBV.Results MARS treatments were associated with significant reduction of albumin bound toxins and water-soluble toxins.Most of the patients showed a positive response with a significant improvement of multiple organ function substantiated by a significant increase in prothrombin time activity (PTA) and median arterial pressure (MAP).There was a decrease in hepatic encephalopathy (HE) grade and Child-Turcotte-Pugh (CTP) scale.Thirty-nine of 188 HBV patients (20.7%) dropped out of the commendatory consecutive therapy ending with lower survival of 43.6% while the rest of the 149 patients had a survival rate of 62.4%.Survival within the ASH and SSH groups were 81.2% and 75.0%,respectively.In the CSH group,end stage patients were predominant (65/151,43%),whereas the early and middle stage patients had a better prognosis:early stage survival,including orthotopic liver transplantation (OLT) survival of 91.7%,middle stage survival of 75%,end stage survival of 33.8%.Conclusions MARS continues to be the most favorable extracorporeal treatment for liver support therapy in China for a wide range of conditions,including the majority of hepatitis B related liver failure conditions.The appropriate application of MARS for the right indications and stage of hepatic failure,as well as the fulfillment of prescribed treatments,will lead to the optimal therapeutic result.

  13. Fissible Deposit Characterization at the Former Oak Ridge K-25 Gaseous Diffusion Plant by {sup 252}CF-Source-Driven Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hannon, T.F.; Mihalczo, J.T.; Mullens, J.A.; Uckan, T.; Valentine, T.E.; Wyatt, M.S.

    1998-05-01

    Laboratory (ORNL) characterize the two largest deposits with the {sup 252}Cf-source-driven transmission (CFSDT) technique, an active neutron interrogation method developed for use at the Oak Ridge Y-12 Plant to identify nuclear weapons components in containers. The active CFSDT measurement technique uses CFSDT time-of-flight measurements of prompt neutrons and gamma rays from an externally introduced {sup 252}Cf source.

  14. A probe for neutron activation analysis in a drill hole using 252Cf, and a Ge(Li) detector cooled by a melting cryogen

    Science.gov (United States)

    Tanner, A.B.; Moxham, R.M.; Senftle, F.E.; Baicker, J.A.

    1972-01-01

    A sonde has been built for high-resolution measurement of natural or neutron-induced gamma rays in boreholes. The sonde is 7.3 cm in diameter and about 2.2 m in length and weighs about 16 kg. The lithium-compensated germanium semiconductor detector is stabilized at -185 to -188??C for as much as ten hours by a cryostatic reservoir containing melting propane. During periods when the sonde is not in use the propane is kept frozen by a gravity-fed trickle of liquid nitrogen from a reservoir temporarily attached to the cryostat section. A 252Cf source, shielded from the detector, may be placed in the bottom section of the sonde for anlysis by measurement of neutron-activation or neutron-capture gamma rays. Stability of the cryostat with changing hydrostatic pressure, absence of vibration, lack of need for power to the cryostat during operation, and freedom of orientation make the method desirable for borehole, undersea, space, and some laboratory applications. ?? 1972.

  15. Standard test method for nondestructive assay of nuclear material in scrap and waste by passive-Active neutron counting using 252Cf shuffler

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the nondestructive assay of scrap and waste items for U, Pu, or both, using a 252Cf shuffler. Shuffler measurements have been applied to a variety of matrix materials in containers of up to several 100 L. Corrections are made for the effects of matrix material. Applications of this test method include measurements for safeguards, accountability, TRU, and U waste segregation, disposal, and process control purposes (1, 2, 3). 1.1.1 This test method uses passive neutron coincidence counting (4) to measure the 240Pu-effective mass. It has been used to assay items with total Pu contents between 0.03 g and 1000 g. It could be used to measure other spontaneously fissioning isotopes such as Cm and Cf. It specifically describes the approach used with shift register electronics; however, it can be adapted to other electronics. 1.1.2 This test method uses neutron irradiation with a moveable Cf source and counting of the delayed neutrons from the induced fissions to measure the 235U equiva...

  16. Analysis of unmodified endotoxin preparations by 252Cf plasma desorption mass spectrometry. Determination of molecular masses of the constituent native lipopolysaccharides.

    Science.gov (United States)

    Caroff, M; Deprun, C; Karibian, D; Szabó, L

    1991-10-01

    Nine unmodified endotoxin preparations constituted of Re-, Rd-, and Rc-type lipopolysaccharides (2 to 5 glycoses), representing four species of enterobacteria were analyzed by 252Cf plasma desorption mass spectrometry. The constituent lipopolysaccharides were characterized by the ion pair: (M-H)- and its corresponding lipid fragment ion. The lipid fragment ion is produced by cleavage of the glycosidic bond of the 3-deoxy-D-manno-oct-2-ulosonic acid unit that substitutes O-6' of the glucosamin beta 1'-6glucosamine ("lipid A backbone") disaccharide of the lipid A moiety. These lipid fragment ions were identical to the (M-H)- ions seen in the spectra of homologous isolated lipid A preparations that were obtained by hydrolysis (pH 4.5, 100 degrees C) promoted by sodium dodecyl sulfate. Since the molecular components present in the endotoxin preparations analyzed are known, the ion pair (M-H)(-)-lipid fragment ion defines the molecular compositions of each individual lipopolysaccharide. Heterogeneity of the R-type endotoxin preparations analyzed was due almost exclusively to differing lipid A moieties. In three Salmonella minnesota 595 Re endotoxin preparations 10 different lipopolysaccharides were identified, only two of which were common to all three preparations. Of the nine lipopolysaccharides identified in two S. minnesota R7 endotoxin preparations, only two were present in both.

  17. Identification of stochastic neutron pulse signal of 252Cf nuclear system based on Elman neural network%基于Elman神经网络的252Cf源核系统随机中子脉冲信号识别方法

    Institute of Scientific and Technical Information of China (English)

    冯鹏; 刘思远; 米德伶

    2011-01-01

    针对252 Cf自发裂变中子源构成的核信息系统,以实际所测随机中子脉冲数据的自相关函数为研究对象,借助仿真实验,利用Elman神经网络对不同质量核材料进行识别.在实测数据的基础上,通过叠加随机抖动,模拟产生了不同质量核材料的相关函数样本,并将其用于神经网络的训练与测试,实验结果表明,训练过的Elman神经网络能够较好地识别相关函数的特征,分辨不同质量的核材料,平均识别率达到85%,综合平均误差为0.04,且具有较高的鲁棒性.%Correct and effective identification of nuclear material is a key part for nuclear weapon's verification. Based on the nuclear information system constructed with 252Cf spontaneous neutron source, the simulated autocorrelation functions are utilized for identification of different fissile mass with Elman neural network. The experimental results show the trained Elman neural net work is able to distinguish the characteristics of autocorrelation function, identify different fissile mass, and the average identifica tion rate reaches 85% and keep average synthesis error smaller than 0. 04 with high robustness.

  18. Experimental microcosm study of the effects of Deepwater Horizon MC-252 oil on the geochemistry and microbiology of Gulf Coast sediment

    Science.gov (United States)

    Donahoe, R. J.; Bej, A.; Raulerson, A.; Rentschler, E. K.

    2011-12-01

    Microcosm experiments were conducted to examine the impact of oil contamination on Gulf Coast sediment geochemistry and microbial population dynamics. Coastal sediment and seawater were collected from a salt marsh at Bayou la Batre, Alabama, which was not severely impacted by the BP Deepwater Horizon accident of April 2010. Sediment/seawater microcosms were set up in glass jars combusted for 5 hours at 450 degrees C. Non-sterile microcosms spiked with 500 ppm of MC-252 oil were sacrificed in duplicate at various time intervals over a 14 day period to establish a data time series. Sterile controls with and without oil and a non-sterile control without oil were sacrificed in duplicate at 14 days for comparison with the time-series experiments. Solid and aqueous phases were separated by centrifugation and prepared for analysis. Sediment mineralogy was determined using X-ray diffraction and acid-extractable sediment chemistry determined using EPA Method 3051A and ICP-OES analysis. The aqueous phase chemistry was analyzed by ICP-OES and ion chromatography. The mineralogy of the salt marsh sediment is predominantly quartz, but includes reactive phases such as clays (smectite, illite), feldspar, and iron oxide. Iron-bearing clays and iron oxides can serve as electron acceptors for the growth of Fe(III)-reducing bacteria. Microwave digestions of the microcosm substrate samples were performed in triplicate and show no significant variation in major element chemistry over the course of the two week experiment, suggesting that observed temporal trends in aqueous geochemistry may be due to ion exchange processes, rather than mineral dissolution reactions. Microcosm substrate trace element data which indicate possible differences with time are being analyzed for statistical significance. Analysis of aqueous solution geochemistry reveals several interesting temporal trends. Iron and manganese were released to solution after 2 days, suggesting the presence of facultative

  19. Determination of the Primary Nuclear Charge of Fission Fragments from their Characteristic K-X-Ray Emission in Spontaneous Fission of Cf252

    International Nuclear Information System (INIS)

    The distribution of nuclear charge in the spontaneous fission of Cf252 has been determined directly by simultaneous measurement of the masses and characteristic K-X-ray energies associated with the primary fission products. The X-rays were detected by a thin Nal (Tl) crystal (or by an argon-filled proportional counter) in coincidence with a pair of solid-state detectors for the complementary fission fragments. Preliminary to the three-parameter study of the charge-mass distribution the gross characteristics of the K-X-rays were examined in some detail. The average yield of K-X-rays is 0.55 ± 0.1 pet fission (the heavy group accounting fot 70% of the total). From delayed-coincidence and fragment time-of-flight experiments it was.found that about 30% of the X-rays are emitted within 0.1 ns after fission, another 30% between 0.1 and 1 ns, 25% between 1 and 10 ns, the remainder appearing as two delayed components of equal intensity with half-lives of ∼30 ns and ∼100 ns. These characteristics indicate that the X-rays arise from internal conversion during de-excitation of the primary fission fragments, an interpretation supported by the observed yield 1 per fission) of 50 - 300 - keV electrons emitted within 2 ps of fission. In the three-parameter experiments the yield and energy of K-X-rays emitted in the first centimeter (ns) of fragment flight were determined as a function of fragment mass. The yield of K-X-rays per fragment is a pronounced saw-tooth function of mass, rising from p) function in better agreement with the empirical rule of equal charge displacement (ECD) than with other postulates for charge division in nuclear fission. (author)

  20. B-cell-specific conditional expression of Myd88p.L252P leads to the development of diffuse large B-cell lymphoma in mice.

    Science.gov (United States)

    Knittel, Gero; Liedgens, Paul; Korovkina, Darya; Seeger, Jens M; Al-Baldawi, Yussor; Al-Maarri, Mona; Fritz, Christian; Vlantis, Katerina; Bezhanova, Svetlana; Scheel, Andreas H; Wolz, Olaf-Oliver; Reimann, Maurice; Möller, Peter; López, Cristina; Schlesner, Matthias; Lohneis, Philipp; Weber, Alexander N R; Trümper, Lorenz; Staudt, Louis M; Ortmann, Monika; Pasparakis, Manolis; Siebert, Reiner; Schmitt, Clemens A; Klatt, Andreas R; Wunderlich, F Thomas; Schäfer, Stephan C; Persigehl, Thorsten; Montesinos-Rongen, Manuel; Odenthal, Margarete; Büttner, Reinhard; Frenzel, Lukas P; Kashkar, Hamid; Reinhardt, H Christian

    2016-06-01

    The adaptor protein MYD88 is critical for relaying activation of Toll-like receptor signaling to NF-κB activation. MYD88 mutations, particularly the p.L265P mutation, have been described in numerous distinct B-cell malignancies, including diffuse large B-cell lymphoma (DLBCL). Twenty-nine percent of activated B-cell-type DLBCL (ABC-DLBCL), which is characterized by constitutive activation of the NF-κB pathway, carry the p.L265P mutation. In addition, ABC-DLBCL frequently displays focal copy number gains affecting BCL2 Here, we generated a novel mouse model in which Cre-mediated recombination, specifically in B cells, leads to the conditional expression of Myd88(p.L252P) (the orthologous position of the human MYD88(p.L265P) mutation) from the endogenous locus. These mice develop a lymphoproliferative disease and occasional transformation into clonal lymphomas. The clonal disease displays the morphologic and immunophenotypical characteristics of ABC-DLBCL. Lymphomagenesis can be accelerated by crossing in a further novel allele, which mediates conditional overexpression of BCL2 Cross-validation experiments in human DLBCL samples revealed that both MYD88 and CD79B mutations are substantially enriched in ABC-DLBCL compared with germinal center B-cell DLBCL. Furthermore, analyses of human DLBCL genome sequencing data confirmed that BCL2 amplifications frequently co-occurred with MYD88 mutations, further validating our approach. Finally, in silico experiments revealed that MYD88-mutant ABC-DLBCL cells in particular display an actionable addiction to BCL2. Altogether, we generated a novel autochthonous mouse model of ABC-DLBCL that could be used as a preclinical platform for the development and validation of novel therapeutic approaches for the treatment of ABC-DLBCL. PMID:27048211

  1. 中国有色将斥资2.52 亿澳元收购澳洲稀土矿商莱纳多数股权

    Institute of Scientific and Technical Information of China (English)

    中国稀土网

    2009-01-01

    @@ 中国有色矿业集团(CN-MC)已同意斥资2.52亿澳元(1.857亿美元)收购澳洲稀土矿商Lynas Corp多数股份. Lynas近日在声明中称,中国有色矿业集团将以每股0.36澳元的价格买人该公司7亿股新股,从而获得51.66%的股份,该消息推动该股最高上涨66%,至0.49澳元.

  2. Measurement of the ambient gamma dose equivalent and kerma from the small 252Cf source at 1 meter and the small 60Co source at 2 meters

    Energy Technology Data Exchange (ETDEWEB)

    Carl, W. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-30

    NASA Langley Research Center requested a measurement and determination of the ambient gamma dose equivalent rate and kerma at 100 cm from the 252Cf source and determination of the ambient gamma dose equivalent rate and kerma at 200 cm from the 60Co source for the Radiation Budget Instrument Experiment (Rad-X). An Exradin A6 ion chamber with Shonka air-equivalent plastic walls in combination with a Supermax electrometer were used to measure the exposure rate and free-in-air kerma rate of the two sources at the requested distances. The measured gamma exposure, kerma, and dose equivalent rates are tabulated.

  3. 252Cf中子照射中国参考人模体24Na比活度的实验研究%Experimental research on specific activity of 24Na using Chinese reference man phantom irradiated by 252Cf neutrons source

    Institute of Scientific and Technical Information of China (English)

    王月兴; 杨翊方; 鲁永杰; 张建国; 邢宏传

    2011-01-01

    Objective To investigate the specific activity of 24Na per unit neutron fluence,AB/Φ,in blood produced for Chinese reference man irratiaded by 252Cf neutron source,and to analyze the effects of scattering neutrons from ground,wall,and ceiling in irradiation site on it.MethodsA 252Cf neutron source of 3 × 108 n/s and the anthropomorphic phantom were used for experiments.The phantom was made from 4 mm thick of outer covering by perspex and the liquid tissue-equivalent substitute in it.The data of phantom dimensions fit into Chinese reference man.The weight ratios of H,N,O and C in substitute equal from source to long axis of phantom were 1.1,2.1,3.1 and 4.1 m,respectively.Both the neutron source and the position of xiphisternum of the phantom were 1.6 m above the floor.ResultsThe average specific activity of 24Na per unit neutron fluence was related to the irradiation-distances,d,and its The AB/ΦM corresponds to that of phantom irradiated by plane-parallel beams,and the value is about more 3% than that by BOMAB phantom reported in literature.It has shown that floor-( wall-)scattered neutrons in irradiation site have significant contribution to the specific activity of 24Na ,but they contributed relatively little to the induced neutron doses.Consequently,using the specific activity of 24 Na for assessing accidental neutron doses received by an individual,the contribution of scattered neutrons in accident site will lead dose to be overestimated,and need to be correct.%目的 研究裂变中子谱照射中国参考人单位中子注量在血液中产生的24Na比活度AB/φ,并分析实验场所地板、墙壁和天花板等的散射中子对测量结果的影响.方法 利用强度约3×108中子/s的252Cf中子源对中国参考人模体进行照射.模体躯干尺寸按中国参考人制作,外壳由4 mm有机玻璃制成,内有人体组织当量液,主要元素的重量比为H∶N∶O∶C=10.6∶2.5∶63.2∶23.7,密度1.007g/cm3(20℃).中子源到模体长轴

  4. Simulation study on highly-enriched uranium components with reflector based on 252Cf source-driven noise analysis method%基于252Cf源驱动噪声分析法的高浓缩铀部件外加反射层效应

    Institute of Scientific and Technical Information of China (English)

    周密; 魏彪; 米德伶; 杨帆

    2014-01-01

    针对高浓缩铀部件外加的反射层材质及厚度之效应可以巧妙避开核查这一问题,依据252Cf中子源驱动噪声分析法原理,采用蒙特卡罗方法模拟研究了高浓缩球形金属铀部件的不同材料、厚度的反射层的效应,获得了相应的时间关联符合计数分布和中子产额.研究结果表明,对同一材料的反射层,反射层厚度愈大,中子产额愈大,即反射效果愈好.对于同一厚度的反射层,反射层材料的密度愈大,中子产额愈大,反射效果愈好.

  5. 252 kV GIS隔离开关特快速暂态过电压试验中触头间隙重复击穿过程研究%Research on Repeated Breakdown Process of Disconnector Contact Gap During Very Fast Transient Overvoltage Test of Overall Switching Process of Disconnector in 252 kV GIS

    Institute of Scientific and Technical Information of China (English)

    詹花茂; 姚林志; 李志兵; 段韶峰; 李成榕; 赵琳

    2014-01-01

    为深入研究气体绝缘开关设备(gas insulated switchgear,GIS)中隔离开关分合空载短母线产生的触头间隙重复击穿现象,实现隔离开关操作全过程特快速暂态过电压(very fast transient overvoltage,VFTO)的准确仿真,建立了252 kV GIS试验平台,对GIS隔离开关分合产生的间隙重复击穿过程及影响因素进行了试验研究。通过同步测量触头间隙电压及长度,获得了隔离开关分合操作中触头间隙击穿电压与间隙长度的统计关系。统计结果表明,操作过程中间隙击穿电压与间隙长度的关系与工频电压下各长度的击穿电压基本吻合,且具有极性效应。每次间隙放电产生的空间电荷促进了后续击穿的发生,且首次放电越剧烈,这种趋势越明显。负载侧残余电压衰减时间常数约为160 min,仿真时可不计重复击穿间歇残余电压的衰减。相同的触头间隙恢复电压下,接地腔体对间隙电场分布影响不大。基于上述研究结果建立了隔离开关操作全过程 VFTO 仿真模型,仿真结果与实测结果基本吻合。%To research the phenomena of repeated breakdown of contact gap of the disconnector in 252 kV gas insulted switchgear (GIS) thoroughly when the disconnector is used to switch on/off no-load short bus and to implement accurate simulation of very fast transient overvoltage (VFTO) during the whole switching process of the disconnector, a test platform for 252 kV GIS is constructed to perform experimental research on repeated breakdown process of the disconnector contact gap and its influencing factors. Through synchronously measuring the gap voltage and the length of contact clearance, the statistic relationship between the breakdown voltage of contact gap and the length of contact clearance during the switching on/off of the disconnector is obtained. Statistical results show that the relationship between contact gap breakdown voltages and the

  6. Measurement of Inclusive ep Cross Sections at High Q2 at sqrt(s) = 225 and 252 GeV and of the Longitudinal Proton Structure Function FL at HERA

    CERN Document Server

    Andreev, V.; Baghdasaryan, S.; Begzsuren, K.; Belousov, A.; Belov, P.; Boudry, V.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Dainton, J.B.; Daum, K.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Herbst, M.; Hildebrandt, M.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jung, A.W.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Morozov, A.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nowak, G.; Nowak, K.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Radescu, V.; Raicevic, N.; Raspereza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Straumann, U.; Sykora, T.; Thompson, P.D.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zhang, Z.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2014-01-01

    Inclusive ep double differential cross sections for neutral current deep inelastic scattering are measured with the H1 detector at HERA. The data were taken with a lepton beam energy of 27.6 GeV and two proton beam energies of Ep = 460 and 575 GeV corresponding to centre-of-mass energies of 225 and 252 GeV, respectively. The measurements cover the region of 6.5 *10^{-4}<=x<= 0.65 for 35<=Q^2<=800 GeV^2 up to y = 0.85. The measurements are used together with previously published H1 data at Ep = 920 GeV and lower Q2 data at Ep = 460, 575 and 920 GeV to extract the longitudinal proton structure function FL in the region 1.5<=Q^2 <=800 GeV^2.

  7. Measurement of inclusive ep cross sections at high Q{sup 2} at √(s) = 225 and 252 GeV and of the longitudinal proton structure function F{sub L} at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Radescu, V.; Raspereza, A.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Bradt, G. [Oxford University, Department of Physics, Oxford (United Kingdom); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Buniatyan, A.; Huber, F.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Rostovtsev, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Cantun Avila, K.B.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Ceccopieri, F.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C.; Olivier, B. [Max-Planck-Institut fuer Physik, Munich (Germany); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K.; Meyer, H. [Universitaet Wuppertal, Fachbereich C, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C. [CPPM, Aix-Marseille Univ, CNRS/IN2P3, Marseille (France); Dobre, M.; Rotaru, M. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Dossanov, A. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Max-Planck-Institut fuer Physik, Munich (Germany); Dubak, A. [Max-Planck-Institut fuer Physik, Munich (Germany); University of Montenegro, Faculty of Science, Podgorica (Montenegro); Egli, S.; Hildebrandt, M.; Horisberger, R. [Paul Scherrer Institut, Villigen (Switzerland); Feltesse, J.; Perez, E.; Schoeffel, L. [CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Turnau, J. [Institute for Nuclear Physics, Cracow (Poland); Grab, C. [ETH, Institut fuer Teilchenphysik, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Lancaster (United Kingdom); Herbst, M.; Jung, A.W.; Schultz-Coulon, H.C. [Universitaet Heidelberg, Kirchhoff-Institut fuer Physik, Heidelberg (Germany); Hladka, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Prague (Czech Republic); Jung, H. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (RU); Kogler, R.; Nowak, K. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (DE); Kostka, P.; Lange, W.; Naumann, T. [DESY, Zeuthen (DE); Landon, M.P.J.; Rizvi, E.; Traynor, D. [University of London, School of Physics and Astronomy, Queen Mary, London (GB); Lubimov, V. [Institute for Theoretical and Experimental Physics, Moscow (RU); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (DE); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (CH); Newman, P.R.; Thompson, P.D. [School of Physics and Astronomy, University of Birmingham, Birmingham (GB); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (ME); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Oxfordshire (GB); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Universita di Roma Tre (IT); INFN Roma 3, Dipartimento di Fisica, Rome (IT); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Prague (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Wegener, D. [Institut fuer Physik, TU Dortmund, Dortmund (DE); Collaboration: H1 Collaboration

    2014-04-15

    Inclusive ep double differential cross sections for neutral current deep inelastic scattering are measured with the H1 detector at HERA.The data were taken with a lepton beam energy of 27.6 GeV and two proton beam energies of E{sub p} = 460 and 575 GeV corresponding to centre-of-mass energies of 225 and 252 GeV, respectively. The measurements cover the region of 6.5 x 10{sup -4} ≤ x ≤ 0.65 for 35 ≤ Q{sup 2} ≤ 800 GeV{sup 2} up to y = 0.85. The measurements are used together with previously published H1 data at E{sub p} = 920 GeV and lower Q{sup 2} data at E{sub p} = 460, 575 and 920 GeV to extract the longitudinal proton structure function F{sub L} in the region 1.5 ≤ Q{sup 2} ≤ 800 GeV{sup 2}. (orig.)

  8. Discovery of a Series of 2-phenyl-N-(2-(pyrrolidin-1-yl)phenyl)acetamides as Novel Molecular Switches that Modulate Modes of Kv7.2 (KCNQ2) Channel Pharmacology: Identification of (S)-2-phenyl-N-(2-(pyrrolidin-1-yl)phenyl)butanamide (ML252) as a Potent, Brain Penetrant Kv7.2 Channel Inhibitor

    Science.gov (United States)

    Cheung, Yiu-Yin; Yu, Haibo; Xu, Kaiping; Zou, Beiyan; Wu, Meng; McManus, Owen B.; Li, Min; Lindsley, Craig W.; Hopkins, Corey R.

    2012-01-01

    A potent and selective inhibitor of KCNQ2, (S)-5 (ML252, IC50 = 69 nM), was discovered after a high-throughput screen of the MLPCN library was performed. SAR studies revealed a small structural change (ethyl group to hydrogen) caused a functional shift from antagonist to agonist activity (37, EC50 = 170 nM), suggesting an interaction at a critical site for controlling gating of KCNQ2 channels. PMID:22793372

  9. 30 CFR 252.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... process of searching for oil and natural gas, including: (1) Geophysical surveys where magnetic, gravity... Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OUTER CONTINENTAL SHELF (OCS) OIL... locality which will be significantly affected by oil and gas activities on the OCS. (c) Affected...

  10. BDML Metadata: 252 [SSBD[Archive

    Lifescience Database Archive (English)

    Full Text Available b0-5fef-4e7a-ae16-30a1dc42b18a 0.105 x 0.105 x 0.5 (micrometer), 40 (second) http://ssbd.qbic.riken.jp/data/...source/Ce_KK_P002/RNAi_Y43F4B.6_061214_03/ http://ssbd.qbic.riken.jp/data/bdml/Ce..._KK_P002/RNAi_Y43F4B.6_061214_03.bdml0.15.xml http://ssbd.qbic.riken.jp/data/pdpml/Ce_KK_P002.pdpml0.05.xml ...http://ssbd.qbic.riken.jp/search/f9cae7b0-5fef-4e7a-ae16-30a1dc42b18a/ http://ssbd.qbic.riken.jp/omero/webclient/?show=dataset-206 ...

  11. 15 CFR 904.252 - Witnesses.

    Science.gov (United States)

    2010-01-01

    ... the witness, or any other action deemed appropriate by the Judge. (f) Testimony in a foreign language... and mileage as witnesses in the courts of the United States. (b) Witness counsel. Any witness not a... otherwise participate in the hearing. (c) Witness exclusion. Witnesses who are not parties may be...

  12. 28 CFR 25.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... Administration DEPARTMENT OF JUSTICE DEPARTMENT OF JUSTICE INFORMATION SYSTEMS The National Instant Criminal... criminal justice agency recognized by the FBI as the agency responsible for providing state-or territory-wide service to criminal justice users of NCIC data. Data source means an agency that provided...

  13. 6 CFR 25.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... the United States, or in the case of a domestic United States air carrier or a United States-flag... a contract or contractual arrangement relating to the manufacture, sale, use, or operation of...

  14. 40 CFR 61.252 - Standard.

    Science.gov (United States)

    2010-07-01

    ... that are no more than 40 acres in area and meet the requirements of 40 CFR 192.32(a) as determined by... owners or operators shall comply with the provisions of 40 CFR 192.32(a) in the operation of tailings piles, the exemption for existing piles in 40 CFR 192.32(a) notwithstanding....

  15. 28 CFR 2.52 - Revocation decisions.

    Science.gov (United States)

    2010-07-01

    ... be to consider granting credit for time on parole in the case of a parole violator originally classified in the very good risk category (pursuant to 28 CFR 2.20) if the following conditions are met. The... CFR 2.21, and an adequate period of renewed supervision following release from reimprisonment...

  16. 7 CFR 252.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... the end product by the agreement value of the donated commodity. NCP Program means a program under... issued to a distributor in an amount equal to the NCP contract value of donated foods contained in an end... recipient agency in an amount equal to the NCP contract value of donated foods contained in an end...

  17. 7 CFR 252.6 - Miscellaneous provisions.

    Science.gov (United States)

    2010-01-01

    ... verification sample to the total NCP sales reported by the processor. (d) Sanctions. Any processor or recipient... the Department, be disqualified from further participation in the NCP Program. Reinstatement may be... misapplies, steals, or obtains by fraud commodities donated for use in the NCP Program, or any funds,...

  18. 7 CFR 252.3 - Administration.

    Science.gov (United States)

    2010-01-01

    ... NCP Program. Only commodities made available without charge or credit under any nutrition program administered by USDA will be available under NCP. FNS will act as the distributing agency and the contracting agency under the NCP Program. The Department will pay costs for delivering donated commodities...

  19. Oxidation of 2,2'-Dihydroxy-3,3'-di-tert-buty-5,5'-dimethoxyl-biphenyl to 3,3'-Di-tert-butylbiphenyl-2,5,2',5'-diquinone with Copper(Ⅱ)Chloride as Catalyst:Synthesis,Structure and Spectral Properties of Diquinone

    Institute of Scientific and Technical Information of China (English)

    LI Jun-Xia; WANG Jian-Ge; HUANG Wei-Ping

    2011-01-01

    Use of free air as oxidant and copper(II)chloride as catalyst,3,3'-di-tert-butylbi-phenyl-2,5,2',5'-diquinone(BBDQ)was prepared via catalytic oxidation of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxy-biphenyl(di-BHA).The yield of reaction attained 95% and the selectivity for BBDQ was 100%.The single-crystal X-ray diffraction analysis reveals that the dihedral angle between two rings(benzene rings for di-BHA and quinone rings for BBDQ)changes from 89.8 to 45.3o,indicating the steric hindrance effects of methyl disappear in the oxidation process.The crystal structures of di-BHA and BBDQ are further confirmed by their spectral characterizations.The probable mechanism for this oxidation process is also discussed.

  20. Use of trioctylphosphine oxide for transplutonium element extraction and purification

    International Nuclear Information System (INIS)

    Investigated was extraction of tri-valent curium, berkelium, californium, einsteinium as well as cerium and europium with trioctylphosphin oxide from lactic acid solutions, containing DTPA and aluminium nitrate depending on the aluminium nitrate and TOPO concentrations and nitric acid solutions of variable concentration as well. Under optimum conditions of extraction chromatography of berkelium studied was the distribution of cobalt, nickel, chromium, iron, aluminium, titanium, zirconium and niobium ions, and the coefficients of berkelium purification from cations investigated were determined. The effect of weight quantities of cation impurities on extraction chromatographic yield of berkelium has been investigated. Examples of practice application of the extraction chromatography with the use of TOPO are given

  1. Progress measures of reducing the steam consumption of QF-W25-2 type turbine generator%降低 QF-W 25-2型汽轮发电机组蒸汽单耗的进步措施

    Institute of Scientific and Technical Information of China (English)

    付江

    2016-01-01

    According to the QF-W25-2 turbo generator unit of actual production , systematically an-alyzed the cause waste of steam .From two aspects of process equipment and implementation of the im-provement measures , the steam consumption from the 3.85 kg/kWh decreased to 3.75 kg/kWh, and formulated the 25 MW generator group of the air quantity regulating valve operation .%结合QF-W25-2型汽轮发电机组生产实际,系统地分析了造成蒸汽浪费的原因,从设备和工艺两个方面实施改进措施,将蒸汽单耗从3.85 kg/kWh降低到3.75 kg/kWh,同时制定了25 MW发电机组气量调节阀操作标准。

  2. Insufficient medications for atrial fibrillation and cardiac dysfunction in elderly hospitalized patients by comparison with related guidelines%252例老年心房纤颤合并心力衰竭的药物治疗与相关指南的差距

    Institute of Scientific and Technical Information of China (English)

    徐军; 缪东培; 包知达; 肖继明; 吕磊; 殷宇刚; 张凯

    2009-01-01

    目的:了解在住院的老年心房纤颤(简称房颤)合并心力衰竭的患者中β受体阻滞剂(Beta blocker)、血管紧张素转换酶抑制剂(ACEI)或血管紧张素Ⅱ受体拮抗剂(ARB)以及抗凝药物的应用现状,探讨与相关指南的差距.方法:通过回顾性分析,对在2004年2月至2007年12月期间住院的252例老年心房纤颤合并心力衰竭的患者进行调查.记录和统计有关的资料. 结果:入院时Beta-blocker、ACEI或ARB和抗凝治疗分别达到85.0%,78.2%,96.4%;但出院时减少至50.4%,54.8%,77.0%,仅8.7%的患者服华法林钠.各种药物的剂量均低于指南的要求,停药或减量的主要原因是药物相关的副作用和对治疗的不依从性. 结论:在住院的老年房颤合并心力衰竭患者中,Beta-blocker、ACEI或ARB以及抗凝药物的应用不足,主要与药物的副作用有关.

  3. Study on Growth Regularity of College Graduates Serving as Village Leaders———Based on Survey Data of 4 252 College Graduates Serving as Village Leaders over China%大学生村官成长规律研究——以全国4252名大学生村官实证调研为样本

    Institute of Scientific and Technical Information of China (English)

    袁芳

    2015-01-01

    Based on the survey data of 4252 college graduates serving as village leaders all over China ,through detailed analysis of four growth stages of college graduates serving as village leaders ,four kinds of internal quality , and four kinds of external conditions ,this paper reveals the essencial relation between various factors in the growth process of college graduates serving as village leaders .It is found that the growth of college graduates serving as village leaders depends on the selection and employment mechanism ,the education and training mechanism ,the ef-ficient and effective coordination and management mechanism ,evaluation and motivation mechanism ,which consti-tutes the dynamical system for the growth of college graduates serving as village leaders .%以全国4 252名大学生村官的调研数据为样本展开研究 ,通过对大学生村官成长四个阶段、四种内在素质、四种外部条件的深入分析 ,揭示了大学生村官成长过程中各种因素的本质联系 ,即大学生村官的成长成才依赖于选拨聘用机制、教育培训机制、考核激励机制和协同管理机制的有效运行 ,它们构成了大学生村官成长成才的动力系统.

  4. 大学生村官成长规律研究——以全国4252名大学生村官实证调研为样本%Study on Growth Regularity of College Graduates Serving as Village Leaders———Based on Survey Data of 4 252 College Graduates Serving as Village Leaders over China

    Institute of Scientific and Technical Information of China (English)

    袁芳

    2015-01-01

    以全国4 252名大学生村官的调研数据为样本展开研究 ,通过对大学生村官成长四个阶段、四种内在素质、四种外部条件的深入分析 ,揭示了大学生村官成长过程中各种因素的本质联系 ,即大学生村官的成长成才依赖于选拨聘用机制、教育培训机制、考核激励机制和协同管理机制的有效运行 ,它们构成了大学生村官成长成才的动力系统.%Based on the survey data of 4252 college graduates serving as village leaders all over China ,through detailed analysis of four growth stages of college graduates serving as village leaders ,four kinds of internal quality , and four kinds of external conditions ,this paper reveals the essencial relation between various factors in the growth process of college graduates serving as village leaders .It is found that the growth of college graduates serving as village leaders depends on the selection and employment mechanism ,the education and training mechanism ,the ef-ficient and effective coordination and management mechanism ,evaluation and motivation mechanism ,which consti-tutes the dynamical system for the growth of college graduates serving as village leaders .

  5. Dicty_cDB: CHP252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available deum elongation factor 2 mRNA, complete cds. 561 0.0 3 CK811111 |CK811111.1 Rasgsc6510 Salivary Gland 4th instar 3rd period (spinning....1 Rasgsc0236 Salivary Gland 4th instar 3rd period (spinning cocoon) Rhynchosciar...a americana cDNA, mRNA sequence. 84 2e-12 2 CK808524 |CK808524.1 Rasgsc1215 Salivary Gland 4th instar 3rd period (spinning...38 Salivary Gland 4th instar 3rd period (spinning cocoon) Rhynchosciara americana cDNA, mRNA sequence. 84 2e...-12 2 CK808525 |CK808525.1 Rasgsc1216 Salivary Gland 4th instar 3rd period (spinning

  6. Library Support Staff Position Classification Studies. SPEC Kit 252.

    Science.gov (United States)

    Stambaugh, Laine, Comp.; Gomez, Joni, Comp.

    1999-01-01

    This survey of Association of Research Libraries (ARL) members gathered data on library support staff classification specifications in ARL libraries, the process for classifying these positions, and salary and title comparisons with similar positions outside of the library. It also asked when the last classification study was performed within the…

  7. Energy dissipation in the cold fission of 252Cf

    International Nuclear Information System (INIS)

    The conversion of energy of collective nuclear motion into internal single particle excitation energy is one of the modes of nuclear energy dissipation. Dissipation and its relation to pair breaking is one of the challenges in nuclear field. A characteristic of low energy fission is odd-even effect. Odd-even staggering in the mass or charge yields and in the total kinetic energies will be of useful to analyze dissipation energy. The odd even effects in the charge distribution of cold fission fragments can be analysed to extract information on the energy dissipation during the passage from the first potential well towards the scission point through the fission barrier. The Q value during a fission process is decomposed into the total kinetic and excitation energies (TKE and TXE)

  8. 24 CFR 252.2 - GNMA right to assignment.

    Science.gov (United States)

    2010-04-01

    ....2 GNMA right to assignment. If the lender-issuer defaults on its obligations under the GNMA Mortgage... defaulting lender-issuer, GNMA will have the right to perfect an assignment of the mortgage to itself. However, before exercising this right, GNMA will attempt to have the Mortgage assigned to another...

  9. /sup 252/Cf plasma desorption in ion implanted mica

    Energy Technology Data Exchange (ETDEWEB)

    Maurette, M. (Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse); Banifatemi, A.; Della-Negra, S.; Le Beyec, Y. (Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire)

    1983-05-12

    The potential of heavy-ion stimulated desorption of ions (HISD) for investigating ion implantation effects in insulators is outlined, and a very strong enhancement in HISD of ionized species from ion implanted mica is reported. This enhancement, which generates heavy-ion clusters up to mass approximately equal to 500 AMU, grows around a critical fluence of implanted ions, and originates from two distinct types of radiation damage defects.

  10. Dicty_cDB: VSA252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .1 Oryza sativa (japonica cultivar-group) genomic DNA, chromosome 9, PAC clone:P0705B06, WORKING DRAFT SEQUE...hromosome 9, BAC clone:OJ1655_B12, WORKING DRAFT SEQUENCE, 1 ordered pieces. 52 0....005 1 AP004777 |AP004777.1 Oryza sativa (japonica cultivar-group) genomic DNA, chromosome 2, PAC clone:P0458B05, WORK...4 1 AC007698 |AC007698.1 Homo sapiens chromosome 4, WORKING DRAFT SEQUENCE, 32 unordered pieces. 46 0.34 1 A...C116804 |AC116804.4 Mus musculus clone RP24-343C24, WORKING DRAFT SEQUENCE, 9 uno

  11. 48 CFR 252.229-7003 - Tax Exemptions (Italy).

    Science.gov (United States)

    2010-10-01

    ... contract number. (ii) The IVA tax exemption claimed pursuant to Article 72 of Decree Law 633, dated October... this transaction is not subject to the tax in accordance with Article 72 of Decree Law 633, dated... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Tax Exemptions...

  12. 48 CFR 252.211-7006 - Radio Frequency Identification.

    Science.gov (United States)

    2010-10-01

    ... supply, as defined in DoD 4140.1-R, DoD Supply Chain Materiel Management Regulation, AP1.1.11: (A... immediate, automatic, and accurate identification of any item in the supply chain of any company, in any..., organizational tool kits, hand tools, and administrative and housekeeping supplies and equipment. (C) Class...

  13. 48 CFR 252.229-7005 - Tax exemptions (Spain).

    Science.gov (United States)

    2010-10-01

    ... Transactions). (6) Impuesto Sobre el Trafico de Empresas (Business Trade Tax). (7) Impuestos Especiales de... Territorial Rustica y Pecuaria (Farmland Real Estate Tax). (16) Impuestos de la Diputacion (County Service Charges). (17) Impuestos Municipal y Tasas Parafiscales (Municipal Tax and Charges). (End of clause)...

  14. 46 CFR 252.31 - Wages of officers and crews.

    Science.gov (United States)

    2010-10-01

    ... OPERATORS OPERATING-DIFFERENTIAL SUBSIDY FOR BULK CARGO VESSELS ENGAGED IN WORLDWIDE SERVICES Calculation of... for the predominant ship type (most voyages) on the service. The purpose of the per month calculation... comparable foreign costs for them. (1) Calculation of per diem WC. The per diem WC shall be calculated by...

  15. 46 CFR 252.34 - Protection and indemnity insurance.

    Science.gov (United States)

    2010-10-01

    ...), as determined in the calculation of the wage differential. (6) U.S.-Foreign cost differential. The U... differential, and determined in the calculation of wage subsidy for the appropriate fiscal period. The... adjusted by substituting a zero cost for such foreign competitor in the calculation of the...

  16. 50 CFR 665.252 - Harvest limitation program.

    Science.gov (United States)

    2010-10-01

    ... sales reports from previous years, and may use information from research sampling and other sources to... permit holders of the reporting method, schedule, and logistics at least 30 days prior to the opening...

  17. Dicty_cDB: SHA252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available estivum cDNA clone G750108G22, mRNA sequence. 44 3.8 1 CD453775 |CD453775.1 WHE2108_D02_H04ZT CS wheat salt-stressed crown...BQ487459.1 WHE2108_D02_H04ZY Wheat salt-stressed crown cDNA library Triticum aestivum cDNA clone WHE2108_D02

  18. Dicty_cDB: VSI252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AGCTAATCTTTAATAGNATTAACAAACCC sequence update 2001. 3.22 Translated Amino Acid sequence ltk**milkkrlttlvll*l...VSSMEAKSMTW*rfryrtwfiifs kknktlklkyenkik*s*slixltn Frame B: ltk**milkkrlttlvll*lhflfqnln*rnsqsnkklylpntlqklv...yri*qrslsqkn *ilp*kklkii*kiltdlaeqii*kllvffkkrfhlwrlnl*lgkdlgielgslfflkki kh*n*nmkik*NKANHLIVINKPSLYVKLKKK--- ---ltk**milk

  19. Dicty_cDB: VSJ252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ber of extensions: 0 Number of successful extensions: 0 Number of sequences better than 10.0: 0 Number of HS...P's better than 10.0 without gapping: 0 Number of HSP's successfully gapped in prelim test: 0 Number of HSP'

  20. 48 CFR 252.225-7013 - Duty-free entry.

    Science.gov (United States)

    2010-10-01

    ...) Scrap or salvage; or (ii) Competitive sale made, directed, or authorized by the Contracting Officer. (d... shipment under 19 CFR part 142 and notify Commander, Defense Contract Management Agency (DCMA) New York... Contractor's name, address, and Commercial and Government Entity (CAGE) code; (2) Prime contract number...

  1. 48 CFR 252.225-7021 - Trade agreements.

    Science.gov (United States)

    2010-10-01

    ...)). These exclusions presently consist of— (A) Textiles, apparel articles, footwear, handbags, luggage, flat..., Belgium, Bulgaria, Canada, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany,...

  2. 48 CFR 252.217-7027 - Contract definitization.

    Science.gov (United States)

    2010-10-01

    ... required by law on the date of execution of the definitive contract action, and (3) any other mutually... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Contract definitization... REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES...

  3. 48 CFR 52.252-2 - Clauses Incorporated by Reference.

    Science.gov (United States)

    2010-10-01

    ..., with the same force and effect as if they were given in full text. Upon request, the Contracting Officer will make their full text available. Also, the full text of a clause may be accessed... (CONTINUED) CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses...

  4. 7 CFR 25.2 - Objective and purpose.

    Science.gov (United States)

    2010-01-01

    ... Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES General... Empowerment Zones and Enterprise Communities in rural areas in order to facilitate the empowerment of the... strategic plan for any nominated rural Empowerment Zone or Enterprise Community; (c) Tax incentives...

  5. 40 CFR 98.252 - GHGs to report.

    Science.gov (United States)

    2010-07-01

    ... for sulfur recovery operations under this subpart. You must follow the calculation methodologies from... recordkeeping requirements of this subpart. (d) CO2 process emissions from each on-site sulfur recovery plant...) CO2 and CH4 emissions from asphalt blowing operations under this subpart. (g) CH4 emissions...

  6. 7 CFR 252.1 - Purpose and scope.

    Science.gov (United States)

    2010-01-01

    ... processing of commodities designated by the Secretary of Agriculture and the minimum requirements which NCP...) Eligible recipient agencies. Recipient agencies shall be eligible to participate in the NCP Program to the extent of their eligibility to receive the food involved in the NCP Program, pursuant to § 250.8 and...

  7. 7 CFR 252.5 - Recipient agency responsibilities.

    Science.gov (United States)

    2010-01-01

    ... participate in the NCP Program. Upon request, FNS will provide recipient agencies with registration forms... products under the NCP Program from a processor utilizing a refund system shall submit a refund application... processors under the NCP Program. The recipient agency may be requested to verify actual purchases of...

  8. 7 CFR 252.4 - Application to participate and agreement.

    Science.gov (United States)

    2010-01-01

    ... products, in accordance with 7 CFR part 210, 225, or 226 appendix A. (17) The processor shall return to FNS... participate. Any food processor is eligible to apply for participation in the NCP Program. Agreement... terms and conditions of the regulations and the NCP agreement; ability to accept and store...

  9. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Science.gov (United States)

    2010-10-01

    ... applied; (2) Produces verifiable, supportable, and documented cost estimates that are an acceptable basis... the cost estimating system to the ACO on a timely basis. (e) Estimating system deficiencies. (1) The... historical costs, and other analyses used to generate cost estimates. (b) General. The Contractor...

  10. Deepwater Horizon MC252 - Oil Spill: Oil Trajectories Maps

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Trajectory maps are produced using GNOME (General NOAA Operational Modeling Environment), which is an oil spill trajectory model developed by OR and...

  11. Transuranium Processing Plant semiannual report of production, status, and plans for period ending December 31, 1975

    Energy Technology Data Exchange (ETDEWEB)

    King, L.J.; Bigelow, J.E.; Collins, E.D.

    1976-10-01

    Between July 1, 1975, and December 31, 1975, maintenance was conducted at TRU for a period of three months, 295 g of curium oxide (enough for approximately 26 HFIR targets) were prepared, 100 mg of high-purity /sup 248/Cm, were separated from /sup 252/Cf that had been purified during earlier periods, 11 HFIR targets were fabricated, and 28 product shipments were made. No changes were made in the chemical processing flowsheets normally used at TRU during this report period. However, three equipment racks were replaced (with two new racks) during this time. In Cubicle 6, the equipment replaced was that used to decontaminate the transplutonium elements from rare earth fission products and to separate curium from the heavier elements by means of the LiCl-based anion-exchange process. In Cubicle 5, the equipment used to separate the transcurium elements by high-pressure ion exchange and to purify berkelium by batch solvent extraction was replaced. Two neutron sources were fabricated, bringing the total fabricated to 79. One source that had been used in a completed project was returned to the TRU inventory and is available for reissue. Three sources, for which no further use was foreseen, were processed to isolate and recover the ingrown /sup 248/Cm and the residual /sup 252/Cf. Eight pellets, each containing 100 ..mu..g of high-purity /sup 248/Cm were prepared for irradiation in HFIR to study the production of /sup 250/Cm. The values currently being used for transuranium element decay data and for cross-section data in planning irradiation-processing cycles, calculating production forecasts, and assaying products are tabulated.

  12. Alicia Poderti, Diccionario del peronismo, Buenos Aires, Editorial Biblos, 2010, 252 p.

    OpenAIRE

    Cristiá, Moira

    2011-01-01

    La editorial Biblios acaba de lanzar dentro de su línea “Lexicon” este diccionario que reúne expresiones, fechas, personajes y conceptos ligados al fenómeno peronista. Mientras que este género de obras suelen presentarse como aportes colectivos, aquí Alicia Poderti asume enteramente el trabajo. Extendiendo y profundizando aquellas reflexiones publicadas en 2005 en el artículo “Peronismo/antiperonismo y el diccionario de los argentinos (1945-1976)”, la doctora en Ciencias Sociales y Humanidade...

  13. 8 CFR 252.5 - Special procedures for deserters from Spanish or Greek ships of war.

    Science.gov (United States)

    2010-01-01

    ... Greek ships of war. (a) General. Under E.O. 11267 of January 19, 1966 (31 FR 807) and 28 CFR 0.109, and E.O. 11300 of August 17, 1966, (31 FR 11009), and 28 CFR 0.110, the Commissioner and immigration... under 8 CFR part 292 without expense to the Government, and that he or she may present such evidence...

  14. 48 CFR 252.222-7002 - Compliance with local labor laws (overseas).

    Science.gov (United States)

    2010-10-01

    ... governing work hours; and (2) Labor regulations including collective bargaining agreements, workers... regulations relating to the performance of work required by this contract. (c) Notwithstanding paragraph (b... ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND...

  15. 24 CFR 92.252 - Qualification as affordable housing: Rental housing.

    Science.gov (United States)

    2010-04-01

    ... established by HUD under 24 CFR 888.111; or (2) A rent that does not exceed 30 percent of the adjusted income... certificate or voucher holder under 24 CFR part 982—Section 8 Tenant-Based Assistance: Unified Rule for Tenant... amount that exceeds the market rent for comparable, unassisted units in the neighborhood. (j) Fixed...

  16. 48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

    Science.gov (United States)

    2010-10-01

    ... cooperative agreements with international or multi-national defense organizations, or sales or transfers by... ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT... government contract, or any combination thereof. (i) Private expense determinations should be made at...

  17. 48 CFR 252.217-7005 - Inspection and manner of doing work.

    Science.gov (United States)

    2010-10-01

    ... Shipping, the U.S. Coast Guard, and the Institute of Electrical and Electronic Engineers, in effect at the... accordance with Occupational Safety and Health Administration regulations (29 CFR 1915.14) before any hot... shall at all times keep the site of the work on the vessel free from accumulation of waste material...

  18. 48 CFR 252.229-7004 - Status of contractors as a direct contractor (Spain).

    Science.gov (United States)

    2010-10-01

    ... commensurate with contingent import tax and duty-free liability. This bank guaranty or fund shall not be released to the Contractor until the Spanish General Directorate of Customs verifies the accounting, export... DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION...

  19. 48 CFR 252.239-7007 - Cancellation or termination of orders.

    Science.gov (United States)

    2010-10-01

    ..., under generally accepted accounting procedures applicable to the provision of telecommunication services... foreseeable reuse. (b) The amount of the Government's liability upon cancellation or termination of any of the... liability upon cancellation or termination of any of the services ordered under this...

  20. 48 CFR 252.209-7007 - Prohibited Financial Interests for Lead System Integrators.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Prohibited Financial... Financial Interests for Lead System Integrators (JUL 2009) (a) Definitions. As used in this clause— (1) Lead... system responsibility. Unless an exception is granted, the Contractor shall not have any direct...

  1. People and things. CERN Courier, Mar 1985, v. 25(2)

    International Nuclear Information System (INIS)

    The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. The main decisions taken at the eleventh meeting of the International Committee for Future Accelerators (ICFA) - held last October at the Leningrad Institute of Nuclear Physics, Gatchina - concerned the setting up of the four international panels which were proposed and agreed at the ICFA Seminar held at the Japanese KEK Laboratory earlier in the year. On 14 January the last of the 48 bending magnets of DESY-II, the new 9 GeV injection synchrotron for electrons and positrons, was installed in the tunnel of the 20 year-old DESY synchrotron in Hamburg. An international history symposium on 'Particle Physics in the 1950s: pions to quarks,' will be held at Fermilab in Batavia, Illinois on 1-4 May 1985

  2. Pressure and Arc Voltage Measurement in a 252 kV SF6 Puffer Circuit Breaker

    Science.gov (United States)

    Zhong, Jianying; Guo, Yujing; Zhang, Hao

    2016-05-01

    The pressure distribution in an arcing chamber is critically important for the SF6 puffer circuit breaker design. In this paper, the pressure variation of four locations in the nozzle was measured by piezoresistive and fiber optical pressure sensors at two current levels of 10 kA and 50 kA. An arc voltage measurement was also taken. The results demonstrate that using either type of sensor with a connecting tube is able to detect the fast pressure variation in circuit breakers, however the possible distortion and delay to the pressure transient caused by the tube need further study.

  3. 24 CFR 236.252 - First, second, and third mortgage insurance premiums.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false First, second, and third mortgage... COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE AND INTEREST REDUCTION PAYMENT FOR RENTAL...

  4. 24 CFR 207.252e - Method of payment of mortgage insurance premiums.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Method of payment of mortgage... COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MULTIFAMILY HOUSING MORTGAGE INSURANCE Contract Rights and...

  5. Calculated neutron air kerma strength conversion factors for a generically encapsulated Cf-252 brachytherapy source

    CERN Document Server

    Rivard, M J; D'Errico, F; Tsai, J S; Ulin, K; Engler, M J

    2002-01-01

    The sup 2 sup 5 sup 2 Cf neutron air kerma strength conversion factor (S sub K sub N /m sub C sub f) is a parameter needed to convert the radionuclide mass (mu g) provided by Oak Ridge National Laboratory into neutron air kerma strength required by modern clinical brachytherapy dosimetry formalisms indicated by Task Group No. 43 of the American Association of Physicists in Medicine (AAPM). The impact of currently used or proposed encapsulating materials for sup 2 sup 5 sup 2 Cf brachytherapy sources (Pt/Ir-10%, 316L stainless steel, nitinol, and Zircaloy-2) on S sub K sub N /m sub C sub f was calculated and results were fit to linear equations. Only for substantial encapsulation thicknesses, did S sub K sub N /m sub C sub f decrease, while the impact of source encapsulation composition is increasingly negligible as Z increases. These findings are explained on the basis of the non-relativistic kinematics governing the majority of sup 2 sup 5 sup 2 Cf neutron interactions. Neutron kerma and energy spectra resul...

  6. Deepwater Horizon MC252 - Oil Spill: Ocean Imaging Corp.'s Aerial Multispectral Oil Mapping System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean Imaging Corp.'s Aerial Multispectral Oil Mapping System employs a customizable 4-spectral channel system and IR imager integrated to allow simultaneous data...

  7. 48 CFR 252.225-7012 - Preference for certain domestic commodities.

    Science.gov (United States)

    2010-10-01

    ..., the following are qualifying countries: Australia Austria Belgium Canada Denmark Egypt Finland France... thereof. Clothing includes items such as outerwear, headwear, underwear, nightwear, footwear,...

  8. Simulation and verification of neutron scattering at 252Cf (D2O) neutron laboratory

    International Nuclear Information System (INIS)

    Background: Although the measurement of neutron dose equivalent was initiated several decades ago, the accuracy of the measurement is not high enough due to the dosimeter's sensitivity and fluence response. Purpose: The aim of this work is to accurately scale the performance parameters and insure the design accuracy of neutron dose equivalent instrument. Methods: MCNP5 was used for simulation analysis of the impact of air, walls, and paraffin in the laboratory respectively on the barrels of neutron counting before experiment. Results: The experimental results show that under ideal conditions, the neutron counting rate decreased with the increase of distance between the source and probe. The air impact on neutron count was up at first and then became weakened, but tended to be strengthened again finally. The neutron scattering rate was less than 10%. And the shorter the distance was, the weaker became air scattering neutrons impact on probe counting. When the probe and the source distance reached 260 cm, the influence of the paraffin barrels was the weakest, which was 1%. The influence of the wall on the neutron count increased with the source-probe distance. When the probe and the source distance was 360 cm, the neutron scattering from the wall was 2 times of that from the source. When the source and the probe distance was 175 cm, all of influences to the neutron scattering reached the minimum, and the measurement data tended to be the most accurate. Conclusion: Through the comparison between experimental and theoretical data, the error of the count rate is less than 30% when the source and the probe distance is between 125-300 cm, confirming with the requirements of the neutron dose measurement technology, which verifies the accuracy of the neutron dose equivalent instrument design. (authors)

  9. 48 CFR 252.211-7005 - Substitutions for military or Federal specifications and standards.

    Science.gov (United States)

    2010-10-01

    ...: Substitutions For Military or Federal Specifications and Standards (NOV 2005) (a) Definition. “SPI process,” as... the Department of Defense under the Single Process Initiative (SPI) for use in lieu of a specific military or Federal specification or standard at specific facilities. Under SPI, these processes...

  10. 48 CFR 252.235-7010 - Acknowledgment of support and disclaimer.

    Science.gov (United States)

    2010-10-01

    ...) contract number(s)). (b) All material, except scientific articles or papers published in scientific...) The Contractor shall include an acknowledgment of the Government's support in the publication of...

  11. 37 CFR 2.52 - Types of drawings and format for drawings.

    Science.gov (United States)

    2010-07-01

    ... applicant must name the color(s), describe where the color(s) appear on the mark, and submit a claim that..., letters, numbers, or any combination thereof without claim to any particular font style, size, or color... is in standard characters and no claim is made to any particular font style, size, or color; (2)...

  12. 48 CFR 52.252-1 - Solicitation Provisions Incorporated by Reference.

    Science.gov (United States)

    2010-10-01

    ... given in full text. Upon request, the Contracting Officer will make their full text available. The... and submitted with its quotation or offer. In lieu of submitting the full text of those provisions... with its quotation or offer. Also, the full text of a solicitation provision may be...

  13. 48 CFR 252.209-7006 - Limitations on Contractors Acting as Lead System Integrators.

    Science.gov (United States)

    2010-10-01

    ... construction of any individual system or element of any system of systems. (c) Representations. (1) The offeror...(s), system of systems, or services described in this solicitation. (d) If the offeror answered...

  14. 48 CFR 252.223-7002 - Safety precautions for ammunition and explosives.

    Science.gov (United States)

    2010-10-01

    ...) (a) Definition. Ammunition and explosives, as used in this clause— (1) Means liquid and solid propellants and explosives, pyrotechnics, incendiaries and smokes in the following forms: (i) Bulk, (ii... components containing no explosives, propellants, or pyrotechnics; (ii) Flammable liquids; (iii) Acids;...

  15. 48 CFR 252.235-7000 - Indemnification under 10 U.S.C. 2354-fixed price.

    Science.gov (United States)

    2010-10-01

    ... or direction of— (i) All or substantially all of the Contractor's business; (ii) All or substantially... Contractor shall buy and maintain, to the extent available, insurance against unusually hazardous risks in... papers and the like, between the Contractor and the subcontractor, as exist between the Government...

  16. 48 CFR 252.225-7009 - Restriction on Acquisition of Certain Articles Containing Specialty Metals.

    Science.gov (United States)

    2010-10-01

    ... using the same production facilities, a common supply chain, and the same or similar production... modified prior to contractual acceptance by the next higher tier in the supply chain. (A) Specialty metals...) Modify paragraph (c)(6) of this clause as necessary to facilitate management of the minimal...

  17. 48 CFR 252.219-7004 - Small business subcontracting plan (test program).

    Science.gov (United States)

    2010-10-01

    ... Subcontracting Plan (Test Program) (AUG 2008) (a) Definition. Subcontract, as used in this clause, means any... Contractor shall submit Standard Form (SF) 295, Summary Subcontract Report, in accordance with the... completed to include semi-annual cumulative— (i) Small business, small disadvantaged business, and...

  18. 48 CFR 252.227-7038 - Patent Rights-Ownership by the Contractor (Large Business).

    Science.gov (United States)

    2010-10-01

    ... corporate structure of which the Contractor is a part; (B) Includes the right to grant sublicenses to the... Contractor made in the performance of work under this contract. (b) Contractor's rights—(1) Ownership. The... subject invention pursuant to an application for an exclusive license submitted in accordance with 37...

  19. Pressure and Arc Voltage Measurement in a 252 kV SF6 Puffer Circuit Breaker

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jianying; GUO Yujing; ZHANG Hao

    2016-01-01

    The pressure distribution in an arcing chamber is critically important for the SF6 puffer circuit breaker design.In this paper,the pressure variation of four locations in the nozzle was measured by piezoresistive and fiber optical pressure sensors at two current levels of 10 kA and 50 kA.An arc voltage measurement was also taken.The results demonstrate that using either type of sensor with a connecting tube is able to detect the fast pressure variation in circuit breakers,however the possible distortion and delay to the pressure transient caused by the tube need further study.

  20. Discovery of Isotopes of the Transuranium Elements with 93 <= Z <= 98

    CERN Document Server

    Fry, C

    2012-01-01

    One hundred and five isotopes of the transuranium elements neptunium, plutonium, americium, curium, berkelium and californium have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  1. Improvement of 2.52 THz Array Transmission Imaging System and Resolution Analysis%2.52THz面阵透射成像系统改进及分辨率分析

    Institute of Scientific and Technical Information of China (English)

    姚睿; 丁胜晖; 李琦; 王骐

    2011-01-01

    THz Array imaging has wide application foreground because of the high imaging speed and large detection area. The design of optical path has great effect on image quality. The THz real imaging system is constructed by use of the SIFIR-50 THz laser as imaging illuminant and Pyrocam Ⅲ thermal imager as array detector. The system has been improved using a series of off-axis parabolic reflectors and polyethylene lens. Imaging experiments on the object of water mark, hollowed-out metal board and resolution board have been made and clear images are obtained. By comparing with original imaging results, it is validated that the imaging quality is well improved. By analyzing the imaging results, resolution of the imaging system can be evaluated and reaches up to 0.6 mm.%太赫兹(THz)面阵成像具有成像速度快和像素多等特点,因此具有广阔的应用前景.成像系统的光路设计对成像质量具有很大影响.利用Pyroeam Ⅲ热像仪作为面阵探测器,利用相干公司SIFIR-50连续太赫兹激光器作为成像光源,搭建太赫兹面阵实时成像系统,并通过多个离轴抛面镜和聚乙烯透镜对原有成像系统进行改进,以人民币水印、镂空金属板和分辨率板为目标进行实时面阵成像,获得了较为清晰的图像,通过与原有成像结果对比,验证了成像质量的提高,并通过分析成像结果对该成像系统的分辨率进行估计,该成像系统分辨率可以达到0.6 mm.

  2. Analytical development of the sup 252 Cf-plasma desorption mass spectroscopy for the structure analysis of biopolymers and synthetic polymers. Analytische Entwicklung der sup 252 Cf-Plasmadesorptions-Massenspektrometrie zur Strukturanalyse von Biopolymeren und synthetischen Polymeren

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, K.

    1991-01-01

    The dissertation had the following aims: A systematic, analytical development of the plasma desorption method, and applications of the plasma desorption mass spectroscopy (PDMS) in primary structure investigations of polypeptides and proteins, and for the determination of the molecular weight of synthetic polymers. For the analytical development of the PDMS, aspects of main interest were the preparation and characterization techniques, and systematic model investigations of the analytical sensitivity, reproducibility and accuray of the molecular weight determination, as well as of the mixture analysis. The objective in the second part of the dissertation was to show application potentials and limits of the PDMS within the framework of analytical tasks of a primary structure characterization of polypeptides and proteins, as well as with regard to the determination of molecular weight and molecular weight distribution of synthetic polymers. (orig.).

  3. Geologic interpretation of seismic data relocation Route 2, Littleton Road grade separation stations 243-252 in Harvard, Mass.

    Science.gov (United States)

    May, James E.; Linehan, Rev. Daniel

    1950-01-01

    During parts of June and July 1949 nine seismic traverses were made at this site. Upon preliminary office development, the velocity data for some of these traverses were though to be inadequate and it was recommended that these lines be re-surveyed. Later surveys (March 1950), however, of nearby sites indicated that the original data were reliable and that a re-survey was unnecessary. The work was done as part of a cooperative program of the Massachusetts Department of Public Works and the United States Geological Survey.

  4. 47 CFR 25.252 - Special requirements for ancillary terrestrial components operating in the 2000-2020 MHz/2180...

    Science.gov (United States)

    2010-10-01

    ..., including takeoff and landing paths. (5) Exceed an aggregate power flux density of −51.8 dBW/m2 in a 1.23... 2200-2290 MHz band. (7) Generate EIRP density, averaged over any two millisecond active transmission... measure wideband EIRP density for purposes of this rule, and narrowband EIRP shall be measured with a...

  5. Health-hazard evaluation report No. HETA 90-252-2167, Northland Terrace Nursing and Rehabilitation Center, Columbus, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, K.W.; Deitchman, S.

    1991-12-01

    In response to a request from management at the Northland Terrace Nursing and Rehabilitation Center (SIC-8051), Columbus, Ohio, a study was undertaken of headaches in workers in the laundry facility and upper respiratory infections associated with delivering Attends diapers. The study included employee interviews, environmental monitoring, and an assessment of the adequacy of the design and performance of the heating, ventilating, and air conditioning system. Northland Terrace was a nursing and rehabilitation center. Employees who work in the laundry facility reported that they experience headache while present in this area which was renovated in 1989. Carbon-dioxide (124389) concentrations exceeded 1000 parts per million. Biologically significant carbon-monoxide (630080) concentrations were not observed. Temperatures in the laundry rooms ranged from 86 to 92 degrees-F. Relative humidities ranged from 48 to 56%. A possible reaction to the dust or the fragrance associated with Attends diapers was not followed to completion as the nursing facility stopped using this product during the study. The authors conclude that there was an inadequate supply of outside air in the laundry and basement areas. The authors recommend measures to improve the ventilation system and reduce the potential for heat stress in the laundry.

  6. 24 CFR 207.252b - Premiums-mortgages insured pursuant to section 223(f) of the Act.

    Science.gov (United States)

    2010-04-01

    ... HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MULTIFAMILY HOUSING MORTGAGE INSURANCE Contract Rights.... (a) The mortgagee, upon the initial-final endorsement of the mortgage for insurance pursuant to...

  7. Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Traub, Richard J.

    2010-03-26

    The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.

  8. 48 CFR 252.225-7043 - Antiterrorism/force protection policy for defense contractors outside the United States.

    Science.gov (United States)

    2010-10-01

    ... foreign government; or (3) A foreign corporation wholly owned by a foreign government. (d) Information and... contract, shall— (1) Affiliate with the Overseas Security Advisory Council, if the Contractor...

  9. SU-E-J-252: Reproducibility of Radiogenomic Image Features: Comparison of Two Semi-Automated Segmentation Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M; Woo, B; Kim, J [Seoul National University, Seoul (Korea, Republic of); Jamshidi, N; Kuo, M [UCLA School of Medicine, Los Angeles, CA (United States)

    2015-06-15

    Purpose: Objective and reliable quantification of imaging phenotype is an essential part of radiogenomic studies. We compared the reproducibility of two semi-automatic segmentation methods for quantitative image phenotyping in magnetic resonance imaging (MRI) of glioblastoma multiforme (GBM). Methods: MRI examinations with T1 post-gadolinium and FLAIR sequences of 10 GBM patients were downloaded from the Cancer Image Archive site. Two semi-automatic segmentation tools with different algorithms (deformable model and grow cut method) were used to segment contrast enhancement, necrosis and edema regions by two independent observers. A total of 21 imaging features consisting of area and edge groups were extracted automatically from the segmented tumor. The inter-observer variability and coefficient of variation (COV) were calculated to evaluate the reproducibility. Results: Inter-observer correlations and coefficient of variation of imaging features with the deformable model ranged from 0.953 to 0.999 and 2.1% to 9.2%, respectively, and the grow cut method ranged from 0.799 to 0.976 and 3.5% to 26.6%, respectively. Coefficient of variation for especially important features which were previously reported as predictive of patient survival were: 3.4% with deformable model and 7.4% with grow cut method for the proportion of contrast enhanced tumor region; 5.5% with deformable model and 25.7% with grow cut method for the proportion of necrosis; and 2.1% with deformable model and 4.4% with grow cut method for edge sharpness of tumor on CE-T1W1. Conclusion: Comparison of two semi-automated tumor segmentation techniques shows reliable image feature extraction for radiogenomic analysis of GBM patients with multiparametric Brain MRI.

  10. 252Cf-based thermal-neutron cross-section gauge for interpretation of neutron logs for oil exploration

    International Nuclear Information System (INIS)

    A newly developed neutron absorption cell measures the thermal-neutron absorption cross sections (Σ/sub w/) of formation brines encountered in logging operations. Thermal-neutron decay time logs with pulsed neutron logging systems are important tools of modern oil exploration technology. These logs yield information about oil saturation characteristics of the formation and oil-water contact location, provided the thermal-neutron cross-section behavior of the host formation is known. This cross section is determined to an important degree by that of the formation brine (Σ/sub w/). Presently, Σ/sub w/ is in most cases estimated from the chemically determined salinity of the brine, since actual measurements with a pulsed neutron logging tool are impractical, requiring several hundred gallons of the brine in a large tank. The chemical analyses are typically performed in a laboratory which is remote from the exploration site. With the portable neutron absorption cell, this measurement is made on site on a sample as small as four liters, with a precision of 0.1% in less than 5 minutes. The results of cell analyses on seventeen brine samples from oil fields in the United States and Canada are discussed. The cross sections measured have been compared with cross sections calculated from chemical and atomic absorption analyses. The agreement is within the experimental errors of the chemical analyses in all cases. Importantly, in all cases boron contributed a noticeable amount to the total absorption cross section. This boron contribution is ignored by conventional brine analyses precluding an accurate estimate of oil saturation, especially in the case of expensive log-inject-log measurements of residual oil preceding secondary or tertiary recovery

  11. Characterization of the occupational exposure and air transported particles using the techniques of PIXE 252Cf PMDS and alpha spectrometry

    International Nuclear Information System (INIS)

    The risk for human health due to exposure to aerosols depends on the intake pattern, the mass concentration and the speciation of the elements present in airborne particles. In this work PDMS (Plasma Desorption Mass Spectrometry) was used as complementary technique to the PIXE (Particle Induced X ray Emission) technique to characterize aerosols samples collected in the environment. The PIXE technique allows the identification of the elements present in the sample and to determine their mass concentrations. The mass spectrometry (PDMS) was used to identify the speciation of these elements present in the samples. The aerosol samples were collected using a six stage cascade impactor in three sites. The Mass Median Aerodynamic Diameter (MMAD) measured indicated that the airborne particulate were in the fine fraction of the aerosols. The theoretical uranium concentration in urine samples using ICRP lung model parameters suggest that the elemental mass concentration in respirable fraction of aerosol and the chemical speciation are important factors to determine the uranium concentration in urine and that the determination of specific solubility parameters for each compound is the most important factor to calculate the uranium concentration in urine. PIXE allows to identify and quantify the elements heavier than Na (Z=11) while PDMS allows to identify the organic and inorganic compounds present in the samples. As these techniques are used as complementary techniques they provide important information about the aerosols characterization. (author)

  12. 75 FR 26091 - Safety Zone; Riser for DEEPWATER HORIZON at Mississippi Canyon 252 Outer Continental Shelf MODU...

    Science.gov (United States)

    2010-05-11

    ... of natural gas, and thereby protect the safety of life, property, and the environment. Oil response... releases of natural gas and increase the safety of life, property, and the environment in the Gulf of... SECURITY Coast Guard 33 CFR Part 147 RIN 1625-AA00 Safety Zone; Riser for DEEPWATER HORIZON at...

  13. 48 CFR 252.251-7001 - Use of Interagency Fleet Management System (IFMS) vehicles and related services.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Use of Interagency Fleet... Fleet Management System (IFMS) vehicles and related services. As prescribed in 251.205, use the following clause: Use of Interagency Fleet Management System (IFMS) Vehicles and Related Services (DEC...

  14. SU-E-T-252: On the Evaluation of Patient Specific IMRT QA Using EPID, Dynalog Files and Patient Anatomy

    International Nuclear Information System (INIS)

    Purpose: This research, investigates the viability of using the Electronic portal imaging device (EPID) coupled with the treatment planning system (TPS), to calculate the doses delivered and verify agreement with the treatment plan. The results of QA analysis using the EPID, Delta4 and fluence calculations using the multi-leaf collimator (MLC) dynalog files on 10 IMRT patients are presented in this study. Methods: EPID Fluence Images in integrated mode and Dynalog files for each field were acquired for 10 IMRT (6MV) patients and processed through an in house MatLab program to create an opening density matrix (ODM) which was used as the input fluence for dose calculation with the TPS (Pinnacle3, Philips). The EPID used in this study was the aSi1000 Varian on a Novalis TX linac equipped with high definition MLC. The resulting dose distributions were then exported to VeriSoft (PTW) where a 3D gamma was calculated using 3mm-3% criteria. The Scandidos Delta4 phantom was also used to measure a 2D dose distribution for all 10 patients and a 2D gamma was calculated for each patient using the Delta4 software. Results: The average 3D gamma for all 10 patients using the EPID images was 98.2% ± 2.6%. The average 3D gamma using the dynalog files was 94.6% ± 4.9%. The average 2D gamma from the Delta4 was 98.1% ± 2.5%. The minimum 3D gamma for the EPID and dynalog reconstructed dose distributions was found on the same patient which had a very large PTV, requiring the jaws to open to the maximum field size. Conclusion: Use of the EPID, combined with a TPS is a viable method for QA of IMRT plans. A larger ODM size can be implemented to accommodate larger field sizes. An adaptation of this process to Volumetric Arc Therapy (VMAT) is currently under way

  15. 40 CFR 421.252 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Science.gov (United States)

    2010-07-01

    ... technology currently available. Except as provided in 40 CFR 125.30 through 125.32, any existing point source... suspended solids 2.050 0.975 pH (1) (1) 1 Within the range of 7.5 to 10.0 at all times. (e) Calciner wet air... solids 721.600 343.200 pH (1) (1) 1 Within the range of 7.5 to 10.0 at all times. (g) Calciner stack...

  16. 48 CFR 252.225-7036 - Buy American Act-Free Trade Agreements-Balance of Payments Program.

    Science.gov (United States)

    2010-10-01

    ...: Buy American Act—Free Trade Agreements—Balance of Payments Program (JUL 2009) (a) Definitions. As used..., Guatemala, Honduras, Mexico, Morocco, Nicaragua, Peru, or Singapore; (8) Free Trade Agreement country end product means an article that— (i) Is wholly the growth, product, or manufacture of a Free Trade...

  17. 48 CFR 252.225-7035 - Buy American Act-Free Trade Agreements-Balance of Payments Program Certificate.

    Science.gov (United States)

    2010-10-01

    ... following provision: Buy American Act—Free Trade Agreements—Balance of Payments Program Certificate (DEC...,” “component,” “domestic end product,” “Free Trade Agreement country,” “Free Trade Agreement country end... States,” as used in this provision, have the meanings given in the Buy American Act—Free Trade......

  18. Neutron multiplicities for the transplutonium nuclides

    International Nuclear Information System (INIS)

    This paper continues, with respect to the transplutonium nuclides, earlier efforts to collate and evaluate data from the scientific literature on the prompt neutron multiplicity distribution from fission and its first moment = ΣnuPnu. The isotopes considered here for which P/sub nu/ and or data (or both) were found in the literature are of americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), and nobelium (No)

  19. Safety evaluation report related to the renewal of the operating license for the University of New Mexico Research Reactor (Docket No. 50-252)

    International Nuclear Information System (INIS)

    This Safety Evaluation Report for the application filed by the University of New Mexico (UNM) for renewal of Operating License No. R-102 to continue to operate its research reactor has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. The facility is located on the campus of the University of New Mexico in Albuquerque, New Mexico. The staff concludes that the reactor can continue to be operated by the University of New Mexico without endangering the health and safety of the public. 7 refs., 7 figs., 2 tabs

  20. Oil-material fractionation in Gulf deep water horizontal intrusion layer: Field data analysis with chemodynamic fate model for Macondo 252 oil spill.

    Science.gov (United States)

    Melvin, A T; Thibodeaux, L J; Parsons, A R; Overton, E; Valsaraj, K T; Nandakumar, K

    2016-04-15

    Among the discoveries of the Deepwater Horizon blowout was the so-called "sub-surface plume"; herein termed the "oil-trapping layer". Hydrocarbons were found positioned at ~1100-1300m with thickness ~100-150m and moving horizontally to the SW in a vertically stratified layer at the junction of the cold abyssal water and the permanent thermocline. This study focuses on its formation process and fate of the hydrocarbons within. The originality of this work to the field is two-fold, first it provides a conceptual framework which places layer origin in the context of a horizontal "intrusion" from the near-field, vertical, blow-out plume and second, it offers a theoretical model for the hydrocarbon chemicals within the horizontal layer as it moves far-afield. The model quantifies the oil-material fractionation process for the soluble and fine particle. The classical Box model, retrofitted with an internal gradient, the "G-Box", allows an approach that includes turbulent eddy diffusion coupled with droplet rise velocity and reactive decay to produce a simple, explicit, transparent, algebraic model with few parameters for the fate of the individual fractions. Computations show the soluble and smallest liquid droplets moving very slowly vertically through the layer appearing within the trapping layer at low concentration with high persistence. The larger droplets move-through this trapping zone quickly, attain high concentrations, and eventually form the sea surface slick. It impacts the field of oil spill engineering science by providing the conceptual idea and the algorithms for projecting the quantities and fractions of oil-material in a deep water, horizontal marine current being dispersed and moving far afield. In the field of oil spill modeling this work extends the current generation near-field plume source models to the far-field. The theory portrays the layer as an efficient oil-material trap. The model-forecasted concentration profiles for alkanes and aromatics against the available field data support the proposed theory and the resulting model.

  1. Dispersants as Used in Response to the MC252-Spill Lead to Higher Mobility of Polycyclic Aromatic Hydrocarbons in Oil-Contaminated Gulf of Mexico Sand

    OpenAIRE

    Zuijdgeest, A.; M. Huettel

    2012-01-01

    After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-column experiments we show that the addition of chemical dispersants (Corexit 9500A) increases the mobility of polycyclic aromatic hydrocarbons (PAHs) in saturated permeable sediments by up to two orde...

  2. Residues 248–252 and 300–304 of the cardiac Na+/Ca2+ exchanger are involved in its regulation by phospholemman

    OpenAIRE

    Zhang, Xue-Qian; Wang, JuFang; Song, Jianliang; Ji, Angi M.; Chan, Tung O.; Cheung, Joseph Y.

    2011-01-01

    Using split cardiac Na+/Ca2+ exchangers (NCX1), we previously demonstrated that phospholemman (PLM) regulates NCX1 by interacting with the proximal linker domain (residues 218–358) of the intracellular loop of NCX1. With the use of overlapping loop deletion mutants, interaction sites are localized to two regions spanning residues 238–270 and residues 300–328 of NCX1. In this study, we used alanine (Ala) linker scanning to pinpoint the residues in the proximal linker domain involved in regulat...

  3. 48 CFR 252.225-7040 - Contractor Personnel Authorized to Accompany U.S. Armed Forces Deployed Outside the United States.

    Science.gov (United States)

    2010-10-01

    ... carry and use them— (A) Safely; (B) With full understanding of, and adherence to, the rules of the use... data. (2) The Contractor shall ensure that all employees in the database have a current DD Form...

  4. Dispersants as used in response to the MC252-spill lead to higher mobility of polycyclic aromatic hydrocarbons in oil-contaminated Gulf of Mexico sand.

    Science.gov (United States)

    Zuijdgeest, Alissa; Huettel, Markus

    2012-01-01

    After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-column experiments we show that the addition of chemical dispersants (Corexit 9500A) increases the mobility of polycyclic aromatic hydrocarbons (PAHs) in saturated permeable sediments by up to two orders of magnitude. Distribution and concentrations of PAHs, measured in the solid phase and effluent water of the columns using GC/MS, revealed that the mobility of the PAHs depended on their hydrophobicity and was species specific also in the presence of dispersant. Deepest penetration was observed for acenaphthylene and phenanthrene. Flushing of the columns with seawater after percolation of the oiled water resulted in enhanced movement by remobilization of retained PAHs. An in-situ benthic chamber experiment demonstrated that aromatic hydrocarbons are transported into permeable sublittoral sediment, emphasizing the relevance of our laboratory column experiments in natural settings. We conclude that the addition of dispersants permits crude oil components to penetrate faster and deeper into permeable saturated sands, where anaerobic conditions may slow degradation of these compounds, thus extending the persistence of potentially harmful PAHs in the marine environment. Application of dispersants in nearshore oil spills should take into account enhanced penetration depths into saturated sands as this may entail potential threats to the groundwater.

  5. UvrD and UvrD252 Counteract RecQ, RecJ, and RecFOR in a rep Mutant of Escherichia coli▿

    OpenAIRE

    Lestini, Roxane; Michel, Bénédicte

    2008-01-01

    Rep and UvrD are two related Escherichia coli helicases, and inactivating both is lethal. Based on the observation that the synthetic lethality of rep and uvrD inactivation is suppressed in the absence of the recombination presynaptic proteins RecF, RecO, or RecR, it was proposed that UvrD is essential in the rep mutant to counteract a deleterious RecFOR-dependent RecA binding. We show here that the synthetic lethality of rep and uvrD mutations is also suppressed by recQ and recJ inactivation...

  6. Dispersants as used in response to the MC252-spill lead to higher mobility of polycyclic aromatic hydrocarbons in oil-contaminated Gulf of Mexico sand.

    Directory of Open Access Journals (Sweden)

    Alissa Zuijdgeest

    Full Text Available After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-column experiments we show that the addition of chemical dispersants (Corexit 9500A increases the mobility of polycyclic aromatic hydrocarbons (PAHs in saturated permeable sediments by up to two orders of magnitude. Distribution and concentrations of PAHs, measured in the solid phase and effluent water of the columns using GC/MS, revealed that the mobility of the PAHs depended on their hydrophobicity and was species specific also in the presence of dispersant. Deepest penetration was observed for acenaphthylene and phenanthrene. Flushing of the columns with seawater after percolation of the oiled water resulted in enhanced movement by remobilization of retained PAHs. An in-situ benthic chamber experiment demonstrated that aromatic hydrocarbons are transported into permeable sublittoral sediment, emphasizing the relevance of our laboratory column experiments in natural settings. We conclude that the addition of dispersants permits crude oil components to penetrate faster and deeper into permeable saturated sands, where anaerobic conditions may slow degradation of these compounds, thus extending the persistence of potentially harmful PAHs in the marine environment. Application of dispersants in nearshore oil spills should take into account enhanced penetration depths into saturated sands as this may entail potential threats to the groundwater.

  7. Dispersants as used in response to the MC252-Spill Lead to higher mobility of polycyclic aromatic hydrocarbons in oil-contaminated Gulf of Mexico sand

    NARCIS (Netherlands)

    Zuijdgeest, A.; Huettel, M.

    2012-01-01

    After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-colu

  8. The 1-way on-line coupled model system MECO(n) – Part 4: Chemical evaluation (based on MESSy v2.52)

    OpenAIRE

    Mertens, Mariano; Kerkweg, Astrid; Jöckel, Patrick; Tost, Holger; Hofmann, Christiane

    2016-01-01

    For the first time a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSyfied ECHAM and COSMO model nested n-times. It features an on-line coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COSMO/MESSy), with the global atmospheric chemistry model ECHAM5/MESSy for Atmospheric Chemistry (EMAC). This on-line coupling allows a consistent mod...

  9. Maria Victoria Navas Sánchez-Élez, Romancero y cancionero de los Navalmorales (toledo), Los Navalmorales, Vientos del Pueblo, 2002, 252 pp.

    OpenAIRE

    González, Raúl Eduardo

    2007-01-01

    Los Navalmorales es una comunidad agrícola de alrededor de 2695 habitantes ubicada en el suroeste de la provincia de Toledo, España, en la comunidad autónoma de Castilla-La Mancha, cerca de los límites con Extremadura. En el volumen aquí reseñado se publica un rico panorama del acervo de romances y cantos cultivados en la localidad, aprovechando la labor previa de algunos recopiladores locales de romances, canciones y coplas, como el trabajo de campo emprendido por María Victoria Navas Sán...

  10. 48 CFR 252.211-7007 - Reporting of Government-Furnished Equipment in the DoD Item Unique Identification (IUID) Registry.

    Science.gov (United States)

    2010-10-01

    ... for sale, and does not ordinarily lose its identity or become a component part of another article when...). (iv) Added or removed code/flag. (v) Marker code (designates which code is used in the...

  11. Genome-wide association analysis of self-reported events in 6135 individuals and 252 827 controls identifies 8 loci associated with thrombosis

    DEFF Research Database (Denmark)

    Hinds, David A; Buil, Alfonso; Ziemek, Daniel;

    2016-01-01

    belonging to the 23andMe cohort of research participants. Eight loci exceeded genome-wide significance. Among the genome-wide significant results, our study replicated previously known venous thromboembolism (VTE) loci near the F5, FGA-FGG, F11, F2, PROCR and ABO genes, and the more recently discovered...

  12. Characterization of surface oil thickness distribution patterns observed during the Deepwater Horizon (MC-252) oil spill with aerial and satellite remote sensing.

    Science.gov (United States)

    Svejkovsky, Jan; Hess, Mark; Muskat, Judd; Nedwed, Tim J; McCall, Jenifer; Garcia, Oscar

    2016-09-15

    Knowledge of the spatial distribution of oil thickness patterns within an on-water spill is of obvious importance for immediate spill response activities as well as for subsequent evaluation of the spill impacts. For long-lasting continuous spills like the 2010 3-month Deepwater Horizon (DWH) event in the Gulf of Mexico, it is also important to identify changes in the dominant oil features through time. This study utilized very high resolution (≤5m) aerial and satellite imagery acquired during the DWH spill to evaluate the shape, size and thickness of surface oil features that dominated the DWH slick. Results indicate that outside of the immediate spill source region, oil distributions did not encompass a broad, varied range of thicknesses. Instead, the oil separated into four primary, distinct characterizations: 1) invisible surface films detectable only with Synthetic Aperture Radar imaging because of the decreased surface backscatter, 2) thicker sheen & rainbow areas (oil (>1mm) that were consistently hundreds of meters long but most commonly only 10-50m wide. Where present within the slick footprint, each of the three distinct visible oil thickness classes maintained its shape characteristics both spatially (at different distances from the source and in different portions of the slick), and temporally (from mid-May through July 2010). The region over the source site tended to contain a more continuous range of oil thicknesses, however, our results indicate that the continuous injection of subsurface dispersants starting in late May significantly altered (lowered) that range. In addition to characterizing the oil thickness distribution patterns through the timeline of one of the world's largest oil spills, this paper also details the extension of using high resolution aerial imagery to calibrate medium resolution satellite data sources such as USA's Thematic Mapper (30m) to provide larger-scale spatial views of major spills, and discusses implications for utilizing such data for oil spill characterizations and spill response. PMID:27389454

  13. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Science.gov (United States)

    2010-10-01

    ... fundamental frequency following the provisions of § 15.31(m). (3) For systems operating in the 23.12-29.0 GHz... are used only for back-up assistance and that operate only when the vehicle is engaged in reverse. (1... emission appear shall be greater than 24.075 GHz. (4) These devices shall operate only when the vehicle...

  14. 78 FR 12252 - Energy Efficiency Program for Commercial and Industrial Equipment: Public Meeting and...

    Science.gov (United States)

    2013-02-22

    ...Detail;dct=FR%252BPR%252BN%252BO%252BSR%252BPS;rpp=25;po=0;D=EER E-2012-BT-STD-0029. This Web page... Standard 90.1- 1999. 73 FR 58772 (Oct. 7, 2008). Section 305 of the Energy Independence and Security Act...

  15. 论海上保险代位求偿权制度--兼谈对我国《海商法》第252~254条的修改%On the System of Right of Subrogation in Marine Insurance--Revision of the Art.252~254 of CMC

    Institute of Scientific and Technical Information of China (English)

    张贤伟

    2001-01-01

    文中结合实体法和程序法有关海上保险代位求偿权的具体规定,力求将二者融会贯通,指出实践中出现或可能出现的问题,明确立法存在的缺陷并提出修改意见,试图更加完善我国海上保险代位求偿权制度.

  16. 76 FR 30089 - Submission for OMB Review; Comment Request

    Science.gov (United States)

    2011-05-24

    ... Application, FNS-252-C, Corporate Supplemental Application, and FNS 252-R, Supplemental Nutrition Assistance... reduced ability to effectively monitor accountability for program compliance and to detect fraud and...

  17. Composition containing transuranic elements for use in the homeopathic treatment of aids

    Energy Technology Data Exchange (ETDEWEB)

    Lustig, D.

    1996-04-18

    A homeopathic remedy consisting of a composition containing one or more transuranic elements, particularly plutonium, for preventing and treating acquired immunodeficiency syndrome (AIDS) in humans, as well as seropositivity for human immunodeficiency virus (HIV). Said composition is characterized in that it uses any chemical or isotopic form of one or more transuranic elements (neptunium, plutonium, americium, curium, berkelium, californium or einsteinium), particularly plutonium, said form being diluted and dynamized according to conventional homeopathic methods, particularly the so-called Hahnemann and Korsakov methods, and provided preferably but not exclusively in the form of lactose and/or saccharose globules or granules impregnated with the active principle of said composition. (author).

  18. TOWARD AN IMPROVED UNDERSTANDING OF STRUCTURE AND MAGNETISM IN NEPTUNIUM AND PLUTONIUM PHOSPHONATES AND SULFONATES

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht-Schmitt, Thomas

    2012-03-01

    This grant supported the exploratory synthesis of new actinide materials with all of the actinides from thorium to californium with the exceptions of protactinium and berkelium. We developed detailed structure-property relationships that allowed for the identification of novel materials with selective ion-exchange, selective oxidation, and long-range magnetic ordering. We found novel bonding motifs and identified periodic trends across the actinide series. We identified structural building units that would lead to desired structural features and novel topologies. We also characterized many different spectroscopic trends across the actinide series. The grant support the preparation of approximately 1200 new compounds all of which were structurally characterized.

  19. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Phuoc [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State; Mcintyre, Dustin [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  20. Composition containing transuranic elements for use in the homeopathic treatment of aids

    International Nuclear Information System (INIS)

    A homeopathic remedy consisting of a composition containing one or more transuranic elements, particularly plutonium, for preventing and treating acquired immunodeficiency syndrome (AIDS) in humans, as well as seropositivity for human immunodeficiency virus (HIV). Said composition is characterized in that it uses any chemical or isotopic form of one or more transuranic elements (neptunium, plutonium, americium, curium, berkelium, californium or einsteinium), particularly plutonium, said form being diluted and dynamized according to conventional homeopathic methods, particularly the so-called Hahnemann and Korsakov methods, and provided preferably but not exclusively in the form of lactose and/or saccharose globules or granules impregnated with the active principle of said composition. (author)

  1. PROCEEDINGS OF THE SYMPOSIUM COMMEMORATING THE 25th ANNIVERSARY OF ELEMENTS 97 and 98 HELD ON JAN. 20, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Seaborg, Glenn T.; Street Jr., Kenneth; Thompson, Stanley G.; Ghiorso, Albert

    1976-07-01

    This volume includes the talks given on January 20, 1975, at a symposium in Berkeley on the occasion of the celebration of the 25th anniversary of the discovery of berkelium and californium. Talks were given at this symposium by the four people involved in the discovery of these elements and by a number of people who have made significant contributions in the intervening years to the investigation of their nuclear and chemical properties. The papers are being published here, without editing, in the form in which they were submitted by the authors in the months following the anniversary symposium, and they reflect rather faithfully the remarks made on that occasion.

  2. 77 FR 41334 - Request for Comments: Customer Due Diligence Requirements for Financial Institutions; Public Hearing

    Science.gov (United States)

    2012-07-13

    ... Requirements for Financial Institutions,'' 77 FR 13046 (March 5, 2012), available at http://www.regulations.gov/#!docketDetail ;D=FINCEN-2012-0001;dct=FR%252BPR%252BN%252BO%252BSR. DATES: This public hearing will be... Comments: Customer Due Diligence Requirements for Financial Institutions; Public Hearing AGENCY:...

  3. 77 FR 76831 - Energy Conservation Program for Consumer Products: Test Procedures for Residential Furnaces and...

    Science.gov (United States)

    2012-12-31

    ... page can be found at: http://www.regulations.gov/#!docketDetail ;dct=FR%252BPR%252BN%252BO%252BSR;rpp... descriptor for each covered product, unless the Secretary determines that: (1) The current test procedures... mode and off mode energy consumption of these products, as required by EISA 2007. 75 FR 64621. For...

  4. Le palais d’Aiétès et son jardin chez Apollonios de Rhodes (Arg., III, v. 194-252). Un exemple de paysage-palimpseste antique ? The Palace of Aeetes and its Garden in Apollonius of Rhodes (Arg., III, lines 194-252). An example of ancient landscape as palimpsest? Il palazzo di Eeta e il suo giardino in Apollonio Rodio (Arg., III, 194-252). Un esempio di paesaggio-palinsesto antico?

    OpenAIRE

    Laury-Nuria André

    2012-01-01

    Lorsque le lecteur découvre au chant III des Argonautiques d’Apollonios de Rhodes l’espace du « paysage urbain » colque, au fur et à mesure de la progression visuelle des personnages, se dessine mentalement tout un espace littéraire fait de réminiscences homériques. L’espace végétal semble composé d’un bouquet d’intertextes de nature endogène tandis que l’architecture palatiale combine structure archaïque et ornements hellénistiques. Nulle trace d’exotisme donc, mais un espace composé de réfé...

  5. Le palais d’Aiétès et son jardin chez Apollonios de Rhodes (Arg., III, v. 194-252. Un exemple de paysage-palimpseste antique ? The Palace of Aeetes and its Garden in Apollonius of Rhodes (Arg., III, lines 194-252. An example of ancient landscape as palimpsest? Il palazzo di Eeta e il suo giardino in Apollonio Rodio (Arg., III, 194-252. Un esempio di paesaggio-palinsesto antico?

    Directory of Open Access Journals (Sweden)

    Laury-Nuria André

    2012-07-01

    Full Text Available Lorsque le lecteur découvre au chant III des Argonautiques d’Apollonios de Rhodes l’espace du « paysage urbain » colque, au fur et à mesure de la progression visuelle des personnages, se dessine mentalement tout un espace littéraire fait de réminiscences homériques. L’espace végétal semble composé d’un bouquet d’intertextes de nature endogène tandis que l’architecture palatiale combine structure archaïque et ornements hellénistiques. Nulle trace d’exotisme donc, mais un espace composé de référents grecs typiques. Du fait de ces référents littéraires, la construction de l’espace palatial urbain emprunte sa configuration même au type d’écriture poétique sollicité par le poète épique : la réécriture. Comment comprendre alors que le palais d’Aiétès puisse être à l’image du palais du souverain grec hellénistique, image idéale d’une architecture s’inscrivant dans l’ordre divin ? Il faut voir ici non seulement la mise en image, l’illustration concrète via l’architecture et, partant, le « paysage urbain » qui se singularise par sa nature hybride, de la volonté de rapprocher Orient et Occident, mais aussi et surtout les moyens mêmes de cette mise en œuvre. Le palais et son jardin ne seraient alors qu’une promesse, un prototype d’un modèle idéal à étendre, grandeur nature, sur l’ensemble du territoire colque, et de l’oïkoumène tout entière.When the reader of the third book of Apollonius of Rhodes discovers, in the course of the characters’ visual progression, the space of a Colchian “urban landscape”, s/he mentally creates a literary space made of Homeric recollections. The garden space seems composed of a bouquet of intertexts of endogenous nature, whereas the palatial architecture combines archaic structure with hellenistic ornamentation. So no trace of the exotic, but a space composed of typical Greek references. As a result of these literary references, the construction of palatial urban space borrows its own configuration from the type of poetic writing the epic poet himself solicits: re-writing. How else can one explain that the palace of Aeetes can be the image of a hellenistic Greek royal palace, the perfect image of an architecture that inscribes itself into a divine order? One should see here not only the reconfiguration, the concrete illustration through the archictecture and, consequently, the urban “landscape” of such an unusual hybrid character, as a result of the wish to reconcile East and West, but also, perhaps especially, the means of its implementation. The palace and garden would then only be a promise, an ideal prototype to be extended, on a large scale, over all of the Colchian land and the entire oekoumene.Quando il lettore scopre, nel terzo libro delle Argonautiche di Apollonio Rodio, lo spazio del ‘paesaggio urbano’ colco, via che progredisce la visuale dei personaggi, viene tracciato mentalmente tutto uno spazio letterario fatto di reminiscenze omeriche. Lo spazio vegetale sembra composto da un insieme di intertesti endogeni, laddove l’architettura palaziale combina struttura arcaica e decorazioni ellenistiche. Nessuna traccia d’esotismo, quindi, ma uno spazio composto di tipici referenti greci. A partire da questi referenti letterari, la costruzione dello spazio palaziale urbano deve la sua stessa configurazione al tipo di scrittura poetica sollecitata dal poeta epico: la riscrittura. Come comprendere, allora, che il palazzo di Eeta possa essere a immagine del palazzo del sovrano greco ellenistico, immagine ideale di un’architettura che si inscrive nell’ordine divino? Occorre vedere qui non soltanto la raffigurazione, l’illustrazione concreta tramite l’architettura e, perciò, il ‘paesaggio urbano’ che si distingue per la sua natura ibrida, dalla volontà di avvicinare Oriente e Occidente, ma anche e soprattutto i mezzi stessi di questa attuazione. Il palazzo e il suo giardino non sarebbero allora altro che una promessa, un prototipo di un modello ideale da estendere, in scala naturale, all’insieme del territorio colco e dell’intera ecumene.

  6. 78 FR 9631 - Energy Efficiency Program for Consumer Products: Energy Conservation Standards for Residential...

    Science.gov (United States)

    2013-02-11

    ...=FR%252BPR%252BN%252BO%252BSR%252BPS;rpp=25;po=0;D=EER E-2012-BT-STD-0047. This Web page contains a... the first required review of minimum standards for boilers under 42 U.S.C. 6295(f)(4)(B). 72 FR 65136... residential boilers. 73 FR 43611. DOE is initiating this rulemaking pursuant to 42 U.S.C. 6295(f)(4)(C),...

  7. Multibeam collection for TN252: Multibeam data collected aboard Thomas G. Thompson from 2010-07-26 to 2010-08-23, departing from Seattle, WA and returning to Newport, OR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at...

  8. Comparison between effectiveness of a low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating dentine hypersensitivity--a 25.2-month evaluation.

    NARCIS (Netherlands)

    Polderman, R.N.; Frencken, J.E.F.M.

    2007-01-01

    OBJECTIVES: The null-hypothesis tested was; there is no difference in effectiveness between a new low-viscosity glass ionomer and a resin-based glutaraldehyde containing primer in treating hypersensitive teeth after 2 years. METHODS: Using a split-mouth design, hypersensitive teeth in 14 adult patie

  9. Le palais d’Aiétès et son jardin chez Apollonios de Rhodes (Arg., III, v. 194-252). Un exemple de paysage-palimpseste antique ?

    OpenAIRE

    André, Laury-Nuria

    2013-01-01

    Lorsque le lecteur découvre au chant III des Argonautiques d’Apollonios de Rhodes l’espace du « paysage urbain » colque, au fur et à mesure de la progression visuelle des personnages, se dessine mentalement tout un espace littéraire fait de réminiscences homériques. L’espace végétal semble composé d’un bouquet d’intertextes de nature endogène tandis que l’architecture palatiale combine structure archaïque et ornements hellénistiques. Nul...

  10. State Children's Health Insurance Program. CMS Should Improve Efforts to Assess whether SCHIP is Substituting for Private Insurance: Report to the Chairman, Committee on Finance, U.S. Senate. GAO-09-252

    Science.gov (United States)

    US Government Accountability Office, 2009

    2009-01-01

    Congress created the State Children's Health Insurance Program (SCHIP) to reduce the number of uninsured children in low-income families that do not qualify for Medicaid. States have flexibility in structuring their SCHIP programs, and their income eligibility limits vary. Concerns have been raised that individuals might substitute SCHIP for…

  11. « Premières domestications proche-orientales : le regard d’un ethnologue », Paléorient, 25/2, (1999), pp. 81-85.

    OpenAIRE

    Bromberger, Christian

    2010-01-01

    Contribution d’un ethnologue, spécialiste des relations entre l’homme et l’animal, au débat sur les premières domestications proche-orientales. L’A. soutient notamment que la domestication 1) est un processus qui ne modifie pas nécessairement l’état biologique de l’animal (on a donc tort de prendre pour seuls critères du passage à l’élevage les transformations morphologiques des populations animales) ; 2) ne répond pas tant à des nécessités économiques qu’à des besoins intellectuels et psychi...

  12. CHARACTERIZATION OF A SYNTHETIC 37-RESIDUE FRAGMENT OF A MONOCLONAL-ANTIBODY AGAINST HERPES-VIRUS BY CAPILLARY ELECTROPHORESIS ELECTROSPRAY (IONSPRAY) MASS-SPECTROMETRY AND CF-252 PLASMA DESORPTION MASS-SPECTROMETRY

    NARCIS (Netherlands)

    KOSTIAINEN, R; LASONDER, E; BLOEMHOFF, W; VANVEELEN, PA; WELLING, GW; BRUINS, AP

    1994-01-01

    A peptide comprising 37 amino acids of the antigen binding site of a monoclonal antibody directed against glycoprotein D of herpes simplex virus was synthesized. The synthetic peptide and the impurities formed in the synthesis were characterized by capillary electrophoresis/ionspray mass spectrometr

  13. Carcaça e não-componentes da carcaça de cordeiros recebendo polpa cítrica úmida prensada em substituição à silagem de milho - DOI: 10.4025/actascianimsci.v29i1.252 Carcass and non-carcass components of lambs fed with pressed citrus pulp replacing corn silage - DOI: 10.4025/actascianimsci.v29i1.252

    Directory of Open Access Journals (Sweden)

    Lina Yumi Noro

    2007-11-01

    Full Text Available O objetivo deste trabalho foi avaliar a substituição da silagem de milho pela polpa cítrica úmida prensada (PCUP sobre as características de carcaça e dos não-componentes da carcaça de cordeiros da raça Santa Inês. Vinte quatro cordeiros com idade média de 90 dias e peso vivo inicial médio de 18 kg foram confinados durante 67 dias, alimentados com dietas contendo níveis crescentes de PCUP em substituição à silagem de milho (0, 25, 50, 75% da MS. Não foi verificada diferença (p>0,05 para peso vivo ao abate (32,8 kg, rendimento de carcaça quente (44,7%, rendimento verdadeiro (50,3% e não-componentes da carcaça. Em relação aos rendimentos dos cortes, apenas o rendimento de lombo foi afetado (pThe objective of this study was to evaluate the replacement of corn silage by pressed citrus pulp (PCP on carcass characteristics and non-carcass components of Santa Ines lambs. Twenty-four lambs with average age of 90 days and initial weight of 18 kg were maintained in feedlot for 67 days, fed with increasing levels of PCP replacing corn silage (0, 25, 50, 75%, DM basis. There was no difference (p>0.05 for live weight at slaughter (32.8 kg, hot carcass yield (44.7%, true yield (50.3% and non-carcass components. In relation to cut yields, only loin yield was affected (p<0.05 by the diet, which showed quadratic response. For the carcass measurements, only the arm length was affected by the diet, showing quadratic behavior. The percentage of fat and muscle showed quadratic behavior according to replacement levels. The results suggest that pressed citrus pulp can substitute corn silage for lambs in feedlot without affecting the carcass characteristics and the non-carcass components.

  14. 77 FR 1474 - Decision and Order Granting a Waiver to Samsung From the Department of Energy Residential...

    Science.gov (United States)

    2012-01-10

    ... Appendix A test procedure DOE published in an interim final rule (75 FR 78810, Dec. 16, 2010) (codified at... on the interim final rule and specifically requested comment on this topic. 76 FR 57613-57614 (Sept....regulations.gov/#!docketDetail ;dct=FR%252BPR%252BN%252BO%252BSR;rpp=10;po=0;D=EERE- 2009-BT-TP-0003. \\3\\...

  15. An atomic beam source for actinide elements: concept and realization

    International Nuclear Information System (INIS)

    For ultratrace analysis of actinide elements and studies of their atomic properties with resonance ionization mass spectroscopy (RIMS), efficient and stable sources of actinide atomic beams are required. The thermodynamics and kinetics of the evaporation of actinide elements and oxides from a variety of metals were considered, including diffusion, desorption, and associative desorption. On this basis various sandwich-type filaments were studied. The most promising system was found to consist of tantalum as the backing material, an electrolytically deposited actinide hydroxide as the source of the element, and a titanium covering layer for its reduction to the metal. Such sandwich sources were experimentally proven to be well suited for the production of atomic beams of plutonium, curium, berkelium and californium at relatively low operating temperatures and with high and reproducible yields. (orig.)

  16. Nuclear fission and the transuranium elements

    Energy Technology Data Exchange (ETDEWEB)

    Seaborg, G.T.

    1989-02-01

    Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs.

  17. Production of transuranium elements

    International Nuclear Information System (INIS)

    The Radiochemical Engineering Development Center (REDC) has the programmatic responsibility for the Department of Energy's Transuranium Element Program. Principle elements from the program are einsteinium, berkelium, and fermium. Targets containing curium oxide mixed with aluminum powder are fabricated by the REDC and irradiated in the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor. Following an irradiation period of 6-12 months, targets are returned to the REDC for chemical processing. Processing operations consists of aluminum dejacketing in a caustic-nitrate solution, filtration, acid dissolution, solvent extraction, anion exchange, and finally a cation exchange to recover the actinides. The processing operations take place in heavily shielded hot cell facilities and all operations are carried out remotely. The chemistry for the separations has been well established over the 26-yr. operating life of the facility

  18. 76 FR 11363 - Defense Federal Acquisition Regulation Supplement; Government Support Contractor Access to...

    Science.gov (United States)

    2011-03-02

    ... Computer Software and Noncommercial Computer Software Documentation. (3) For Small Business Innovation... (noncommercial technical data), 252.227-7014 (noncommercial software and software documentation), 252.227-7015 (commercial technical data), and 252.227-7018 (Small Business Innovation Research (SBIR)). The exception...

  19. 76 FR 71922 - Defense Federal Acquisition Regulation Supplement: Separation of Combined Provisions and Clauses...

    Science.gov (United States)

    2011-11-21

    .... * * * * * (ii) 252.209-7002, Disclosure of Ownership or Control by a Foreign Government. (iii) 252.209-7003...) 252.209-7001, Disclosure of Ownership or Control by the Government of a Terrorist Country. Applies to... part in a foreign country; and (B) A foreign government controls wage rates or material prices and...

  20. 78 FR 72033 - Approval and Promulgation of Implementation Plans; Florida: General Requirements and Gasoline...

    Science.gov (United States)

    2013-12-02

    ... 5/9/2007 6/1/2009......... Permit Forms. 63 FR 26103...... * * * * * * * Chapter 62-252 Gasoline...-252.300 Gasoline 5/9/2007 6/1/2009......... Dispensing 63 FR 26103...... Facilities-Stage I Vapor Recovery. 62-252.400 Gasoline 5/9/2007 6/1/2009......... Dispensing 63 FR 26103...... Facilities Stage...

  1. Comment on Spracklandus Hoser, 2009 (Reptilia, Serpentes, ELAPIDAE): request for confirmation of availability of the generic name and for the nomenclatural validation of the journal in which it was published (Case 3601; BZN 70:234–237; 71:30–38; 133-135,181-182 ,252-253)

    Science.gov (United States)

    Rhodin, Anders G.J.; Kaiser, Hinrich; van Dijk, Peter Paul; Wüster, Wolfgang; O’Shea, Mark; Archer, Michael; Auliya, Mark; Boitani, Luigi; Bour, Roger; Clausnitzer, Viola; Contreras-MacBeath, Topiltzin; Crother, Brian I.; Daza, Juan M.; Driscoll, Carlos A.; Flores-Villela, Oscar; Frazier, Jack; Fritz, Uwe; Gardner, Alfred L.; Gascon, Claude; Georges, Arthur; Glaw, Frank; Grazziotin, Felipe G.; Groves, Colin P.; Haszprunar, Gerhard; Havaš, Peter; Hero, Jean-Marc; Hoffmann, Michael; Hoogmoed, Marinus S.; Horne, Brian D.; Iverson, John B.; Jäch, Manfred; Jenkins, Christopher L.; Jenkins, Richard K.B.; Kiester, A. Ross; Keogh, J. Scott; Lacher, Thomas E.; Lovich, Jeffrey E.; Luiselli, Luca; Mahler, D. Luke; Mallon, David P.; Mast, Roderic; McDiarmid, Roy W.; Measey, John; Mittermeier, Russell A.; Molur, Sanjay; Mosbrugger, Volker; Murphy, Robert W.; Naish, Darren; Niekisch, Manfred; Ota, Hidetoshi; Parham, James F.; Parr, Michael J.; Pilcher, Nicolas J.; Pine, Ronald H.; Rylands, Anthony B.; Sanderson, James G.; Savage, Jay M.; Schleip, Wulf; Scrocchi, Gustavo J.; Shaffer, H. Bradley; Smith, Eric N.; Sprackland, Robert; Stuart, Simon N.; Vetter, Holger; Vitt, Laurie J.; Waller, Tomás; Webb, Grahame; Wilson, Edward O.; Zaher, Hussam; Thomson, Scott

    2015-01-01

    In Case 3601 Raymond Hoser has asked the Commission to validate for the purposes of nomenclature the name Spracklandus Hoser, 2009, and ‘the journal in which it was published,’ issue 7 of the Australasian Journal of Herpetology (AJH). We note that the entire run of AJH has been written, edited, and published solely by Hoser. Although his requests to the Commission were presented as narrow and, in his words, ‘routine matters,’ we are convinced that they represent an important tipping-point with broad implications of major concern for zoological taxonomy and nomenclature as a whole and, by extension, the greater scientific community. Since Hoser’s actions and works have failed to follow scientific best practices (e.g. Turtle Taxonomy Working Group, 2007, 2014; Kaiser et al., 2013; Kaiser, 2014) and both the Commission’s general Recommendations and Code of Ethics in Appendix A, the global herpetological community has widely rejected his taxonomic decisions and resultant nomenclature. This has unfortunately caused a confusing dual nomenclature to develop in the herpetological community, with most boycotting or ignoring Hoser’s 700+ new names coined in the AJH, while he and a few personal followers actively promote their usage. We believe that suppression of the name Spracklandus, and all issues of AJH, is the only effective way to bring this contentious and confusing issue to resolution. The plenary power available under Article 81.1 of the Code exist specifically to allow the Commission to make rulings in individual cases that disturb stability and cause confusion, whether the works are Code-compliant or not. We maintain that it is in the interest of nomenclatural stability, not only for herpetology, but for all of zoological taxonomy, that the plenary power be invoked to declare the works in AJH unavailable, regardless of any narrow interpretation of their technical Code-compliance. We present our arguments for rejection of the validity of AJH in the following commentary. In view of the wide-reaching implications of this case for all of zoology, and reflecting the deep and broad-based community concern over these issues, our contributing authors include 70 global scientific leaders and accomplished amateurs from a wide variety of zoological disciplines.

  2. Dietary exposure to benzoates (E210-E213), parabens (E214-E219), nitrites (E249-E250), nitrates (E251-E252), BHA (E320), BHT (E321) and aspartame (E951) in children less than 3 years old in France.

    Science.gov (United States)

    Mancini, F R; Paul, D; Gauvreau, J; Volatier, J L; Vin, K; Hulin, M

    2015-01-01

    This study aimed to estimate the exposure to seven additives (benzoates, parabens, nitrites, nitrates, BHA, BHT and aspartame) in children aged less than 3 years old in France. A conservative approach, combining individual consumption data with maximum permitted levels, was carried out for all the additives. More refined estimates using occurrence data obtained from products' labels (collected by the French Observatory of Food Quality) were conducted for those additives that exceeded the acceptable daily intake (ADI). Information on additives' occurrence was obtained from the food labels. When the ADI was still exceeded, the exposure estimate was further refined using measured concentration data, if available. When using the maximum permitted level (MPL), the ADI was exceeded for benzoates (1.94 mg kg(-1) bw day(-1)), nitrites (0.09 mg kg(-1) bw day(-1)) and BHA (0.39 mg kg(-1) bw day(-1)) in 25%, 54% and 20% of the entire study population respectively. The main food contributors identified with this approach were current foods as these additives are not authorised in specific infant food: vegetable soups and broths for both benzoates and BHA, delicatessen and meat for nitrites. The exposure estimate was significantly reduced when using occurrence data, but in the upper-bound scenario the ADI was still exceeded significantly by the age group 13-36 months for benzoates (2%) and BHA (1%), and by the age group 7-12 months (16%) and 13-36 months (58%) for nitrites. Measured concentration data were available exclusively for nitrites and the results obtained using these data showed that the nitrites' intake was below the ADI for all the population considered in this study. These results suggest that refinement of exposure, based on the assessment of food levels, is needed to estimate the exposure of children to BHA and benzoates for which the risk of exceeding the ADI cannot be excluded when using occurrence data. PMID:25686474

  3. Dietary exposure to benzoates (E210-E213), parabens (E214-E219), nitrites (E249-E250), nitrates (E251-E252), BHA (E320), BHT (E321) and aspartame (E951) in children less than 3 years old in France.

    Science.gov (United States)

    Mancini, F R; Paul, D; Gauvreau, J; Volatier, J L; Vin, K; Hulin, M

    2015-01-01

    This study aimed to estimate the exposure to seven additives (benzoates, parabens, nitrites, nitrates, BHA, BHT and aspartame) in children aged less than 3 years old in France. A conservative approach, combining individual consumption data with maximum permitted levels, was carried out for all the additives. More refined estimates using occurrence data obtained from products' labels (collected by the French Observatory of Food Quality) were conducted for those additives that exceeded the acceptable daily intake (ADI). Information on additives' occurrence was obtained from the food labels. When the ADI was still exceeded, the exposure estimate was further refined using measured concentration data, if available. When using the maximum permitted level (MPL), the ADI was exceeded for benzoates (1.94 mg kg(-1) bw day(-1)), nitrites (0.09 mg kg(-1) bw day(-1)) and BHA (0.39 mg kg(-1) bw day(-1)) in 25%, 54% and 20% of the entire study population respectively. The main food contributors identified with this approach were current foods as these additives are not authorised in specific infant food: vegetable soups and broths for both benzoates and BHA, delicatessen and meat for nitrites. The exposure estimate was significantly reduced when using occurrence data, but in the upper-bound scenario the ADI was still exceeded significantly by the age group 13-36 months for benzoates (2%) and BHA (1%), and by the age group 7-12 months (16%) and 13-36 months (58%) for nitrites. Measured concentration data were available exclusively for nitrites and the results obtained using these data showed that the nitrites' intake was below the ADI for all the population considered in this study. These results suggest that refinement of exposure, based on the assessment of food levels, is needed to estimate the exposure of children to BHA and benzoates for which the risk of exceeding the ADI cannot be excluded when using occurrence data.

  4. Synthesis and Crystal Structure of One Mixed- ligand Coordination Polymer Based on the Novel Terphenyl-2,5,2',5'-tetracarboxylic Acid Ligand%Synthesis and Crystal Structure of One Mixed- ligand Coordination Polymer Based on the Novel Terphenyl-2,5,2',5'-tetracarboxylic Acid Ligand

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiu-Tang; ZHANG Lu-Qing; ZHANG Liang-Dong; FAN Li-Ming; WEI Pei-Hai; ZHANG Shu-Xiang

    2012-01-01

    Solvothermal reaction of aromatic terphenyl-2,5,2',5'-tetracarboxylic acid (Hnqptc) ligand and the transitional metal cation of Mn11 in the presence of 3-(2-pyridyl)pyrazole (pp) affords one new coordination polymer, [Mn(qptc)0.5(pp)2]n·n(H2O) (1). The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, TGA, and magnetism. The carboxyl groups of qptc4 exhibit a μ1-η1:η0 coordination mode, and the qptc4- acts as a H-shaped ligand linking the Mn11 centers together to form a 2D polymeric [Mn(qptc)0.5]n layer. The crystal of 1 crystallizes in orthorhombic, space group Pbca with a = 9.3119(12), b = 20.848(3), c = 26.134(3) A, V= 5073.4(11) A3, Z= 8, C27HIgMnN6O5,Mr=562.42, Dc = 1.473 g/cm3, F(000) = 2304 and μ(MoKa) = 0.571 mm-1. The final R = 0.0468 and wR = 0.1196 for 4429 observed reflections with I 〉 2σ(I) and R = 0.0797 and wR = 0.1383 for all data.

  5. Subroutines to Simulate Fission Neutrons for Monte Carlo Transport Codes

    OpenAIRE

    Lestone, J. P.

    2014-01-01

    Fortran subroutines have been written to simulate the production of fission neutrons from the spontaneous fission of 252Cf and 240Pu, and from the thermal neutron induced fission of 239Pu and 235U. The names of these four subroutines are getnv252, getnv240, getnv239, and getnv235, respectively. These subroutines reproduce measured first, second, and third moments of the neutron multiplicity distributions, measured neutron-fission correlation data for the spontaneous fission of 252Cf, and meas...

  6. 78 FR 16443 - Energy Efficiency Program for Consumer Products: Energy Conservation Standards for Ceiling Fans...

    Science.gov (United States)

    2013-03-15

    ... to the docket Web page can be found at: www.regulations.gov/#!docketDetail ;dct=FR%252BPR%252BN%252BO... light kits in the CFR at 10 CFR 430.32(s). 70 FR 60407, 60413. An additional final rule technical... sockets other than medium-screw base or pin-based fluorescent lamps in the CFR. 72 FR 1270. In a...

  7. Anthropometric Somatotype of Kshatriya and Kurmi of Uttar Pradesh: population and gender differences

    OpenAIRE

    Shivani Chandel; S.L. Malik

    2012-01-01

    The aim of this cross-sectional study was to describe the population and gender related variations of the somatotype, employing Heath and Carter's method, in Kshatriya and Kurmi population residing in a rural region of Uttar Pradesh. The sample included 1008 adult Kshatriya (252 males and 252 females) and Kurmi (252 males and 252 females), belonging to the age group of 18-40 yrs. The population and gender differences were evaluated by one-way ANOVA. The results suggest that average body physi...

  8. 48 CFR 552.211-92 - Radio Frequency Identification (RFID) using passive tags.

    Science.gov (United States)

    2010-10-01

    ... with 48 CFR clause 252.211-7006. Shipments to GSA Distribution Centers with final destinations to DLA and DoD shall be in compliance to 48 CFR 252.211-7006. Copies may be obtained from http://www.access.gpo.gov/nara/cfr/cfr-table-search.html. (End of clause)...

  9. 77 FR 19128 - Defense Federal Acquisition Regulation Supplement: Separation of Combined Provisions and Clauses...

    Science.gov (United States)

    2012-03-30

    ... grammatical changes to paragraph (a) of 252.229-7005, Tax Exemptions (Spain). III. Executive Orders 12866 and... proposed rule in the Federal Register at 76 FR 71922 on November 21, 2011, to separate provisions and... (Spain)... 252.229-7013, Tax Exemptions (Spain)--Representation. Conforming changes are also required...

  10. Genetic and bibliographic information: PLEKHG4 [GenLibi

    Lifescience Database Archive (English)

    Full Text Available 4 human Autosomal dominant cerebellar ataxia; Cerebellar Ataxia (MeSH) Nervous System Diseases (C10) > Central Nervous System Diseas...es (C10.228) > Brain Diseases (C10.228.140) > Cerebellar Diseases (C10.228.140.252)... > Cerebellar Ataxia (C10.228.140.252.190) Nervous System Diseases (C10) > Neurol

  11. 48 CFR 229.402-70 - Additional clauses.

    Science.gov (United States)

    2010-10-01

    ... performance will be in Spain. (f) Use the clause at 252.229-7006, Value Added Tax Exclusion (United Kingdom.... (i) Use the clause at 252.229-7009, Relief from Customs Duty and Value Added Tax on Fuel (Passenger... SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING REQUIREMENTS TAXES Contract Clauses...

  12. NCBI nr-aa BLAST: CBRC-CBRE-01-0523 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CBRE-01-0523 ref|YP_040542.1| hypothetical protein SAR1129 [Staphylococcus aureus subsp. aureus... MRSA252] emb|CAG40132.1| putative membrane protein [Staphylococcus aureus subsp. aureus MRSA252] YP_040542.1 8e-04 25% ...

  13. Si+ ion implantation reduces the bacterial accumulation on the Ti6Al4V surface under flow

    OpenAIRE

    González-Martín, M. L.; Gallardo-Moreno, A. M.; Pacha-Olivenza, M. A.; González-Carrasco, José Luis

    2010-01-01

    Póster presentado al BIO-COAT: "Surface modification and functionalization of materials for biomedical applications" celebrado en Zaragoza el 24 de junio de 2010.-- Publicado como artículo en Journal of Physics: Conference Series 252(1): http://dx.doi.org/10.1088/1742-6596/252/1/012017

  14. 78 FR 71558 - Insurance Cost Information Regulation

    Science.gov (United States)

    2013-11-29

    ... April 11, 2000 (65 FR 19477-78). For access to the docket to read background documents or comments... their prospective purchasers.\\4\\ \\4\\ 58 FR 12545. B. Public Law 112-252 Public Law 112-252, passed by... April 11, 2000 (65 FR 19477-78) or you may visit http://www.dot.gov/privacy.html . Authority: 49...

  15. 78 FR 36108 - Defense Federal Acquisition Regulation Supplement; Defense Trade Cooperation Treaties With...

    Science.gov (United States)

    2013-06-17

    ... contractor to be aware of export controls as they apply to the performance of DoD contracts. (b) It is the.... 225.7901-4 Contract clause. Use the clause at 252.225-7048, Export-Controlled Items, in all... Treaty- eligible requirements'' are defined in contract clause DFARS 252.225- 7047, Exports by...

  16. Dicty_cDB: AFO251 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) Pyrocystis lunula actin mRNA, comp... 252 3e-66 AY221950_1( AY221950 |pid:none) Pseudo-nitzschia multise...ries actin... 252 3e-66 protein update 2009. 4.26 PSORT psg: 0.84 gvh: 0.59 alm: 0.

  17. Nuclear Chemistry Institute, Mainz University. Annual Report 1995

    International Nuclear Information System (INIS)

    The annual report of the Institut fuer Kernchemie addresses inter alia three main research activities. The first belongs to the area of basic research, covering studies in the fields of nuclear fission, chemistry of the super-heavy elements and of heavy-ion reactions extending from the Coulomb barrier to relativistic energies, and nuclear astrophysics in connection with the ''r process''. By means of laser technology, high-precision data could be measured of the ionization energies of berkelium and californium. Studies of atomic clusters in the vacuum of an ionization trap revealed interesting aspects. The second major activity was devoted to the analysis of environmental media, applying inter alia neutron activation analysis and resonance ionization mass spectroscopy (RIMS). The third activity resulted in the development of novel processes, or the enhancement of existing processes or methods, for applications in basic research work and in environmental analytics. Another item of interest is the summarizing report on the operation of the TRIGA research reactor. (orig./SR)

  18. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Chemistry; Smith, B.F. [Los Alamos National Lab., NM (United States)

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about a factor of 5 to 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  19. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry); Smith, B.F. (Los Alamos National Lab., NM (United States))

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}'s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}'s for these actinides are about a factor of 5 to 10 greater than the K{sub d}'s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}'s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  20. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-Dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and Tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States); Smith, B.F. [Los Alamos National Lab., NM (United States)

    1992-07-01

    The first measurements of distribution coefficients (k{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about about a factor of 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand. 9 refs., 2 figs., 1 tab.

  1. Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

    Science.gov (United States)

    Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

    2016-09-01

    A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

  2. Paul Scherrer Institute Scientific Report 1999. Volume I: Particles and Matter

    International Nuclear Information System (INIS)

    Although originally planned for fundamental research in nuclear physics, the particle beams of pions, muons, protons and neutrons are now used in a large variety of disciplines in both natural science and medicine. The beams at PSI have the world's highest intensities and therefore allow certain experiments to be performed, which would not be possible elsewhere. The highlight of research this year was the first-ever determination of the chemical properties of the superheavy element 107 Bohrium. This was undertaken, by an international team led by H. Gaeggeler of PSI's Laboratory for Radiochemistry. Bohrium was produced by bombarding a Berkelium target with Neon ions from the Injector I cyclotron and six atoms were detected after having passed through an online gas chromatography device. At the Laboratory for Particle Physics the focus has shifted from nuclear physics to elementary particle physics with about a fifty-fifty split between investigations of rare processes or particle decays using the high intensity muon, pion and recently also polarized neutron beams of PSI, and research at the highest energy frontier at CERN (Geneva) and DESY (Hamburg). Important space instrumentation has been contributed by the Laboratory for Astrophysics to the European Space Agency and NASA satellite programmes. The Laboratory for Micro and Nanotechnology continued to focus on research into molecular nanotechnology and SiGeC nanostructures, the latter with the aim of producing silicon based optoelectronics. Progress in 1999 in these topical areas is described in this report. A list of scientific publications in 1999 is also provided

  3. Biomedical neutron research at the Californium User Facility for neutron science

    International Nuclear Information System (INIS)

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252Cf sources. Three projects at the CUF that demonstrate the versatility of 252Cf for biological and biomedical neutron-based research are described: future establishment of a 252Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy

  4. Biomedical neutron research at the Californium User Facility for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.C. [Oak Ridge National Lab., TN (United States); Byrne, T.E. [Roane State Community College, Harriman, TN (United States); Miller, L.F. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact {sup 252}Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with {sup 252}Cf sources. Three projects at the CUF that demonstrate the versatility of {sup 252}Cf for biological and biomedical neutron-based research are described: future establishment of a {sup 252}Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded {sup 252}Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy.

  5. Californium Multiplier (CFX)

    International Nuclear Information System (INIS)

    The availability of 252Cf as an economical high-intensity neutron source has made it possible to construct compact neutron irradiation devices with widespread applications. The simplest such device consists of a single 252Cf source within a moderating and shielding medium. Higher neutron flux levels can be attained either through the use of more 252Cf or through source multiplication by means of a subcritical uranium assembly. Although the use of larger 252Cf sources to achieve higher neutron flux is technically straightforward, an economic penalty is paid as the source strength is increased. Larger californium sources imply larger initial investments to cover the cost of source material and larger operating costs resulting from the decay of the 252Cf source. A Californium Multiplier, the CFX, which produces a flux enhancement of 30 when compared to a conventional moderated 252Cf system has been designed, licensed, built, and tested by IRT Corporation. Such systems are now available on a commercial basis for both neutron radiography and neutron activation analysis. The first commercial CFX system was installed at the Research Laboratories of Eastman Kodak Company in Rochester, NY, in March 1975. This device, using 1 mg of 252Cf, is very stable and the neutron flux generated by the CFX is very reproducible. The performance characteristics of this system are summarized

  6. Application of TSH bioindicator for studying the biological efficiency of radiation

    International Nuclear Information System (INIS)

    Dose response relationships for various endpoints (gene and lethal mutations, cell cycle alterations) in somatic cells of Tradescantia clone 4430 were established for X-rays and for mixed fast and thermal neutrons from Cf-252 source of KAERI and from U-120 cyclotron of INP. This was a pilot experiment to check if it is possible to establish the relative biological effectiveness values for Cf-252 irradiated TSH cells, with and without boron ion pretreatment, in conditions of mutual KAERI-INP experiment. When T-4430 was pretreated with boron ion, there was and enhancement in biological efficacy of neutron form Cf-252 source. 2 tabs., 7 figs., 7 refs. (Author)

  7. Dicty_cDB: Contig-U11827-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available r (1..6, M) - Chromosome length - Start point - End point - Strand (PLUS/MINUS) -...U11827-1Q.Seq.d Length = 1277 Score = 500 bits (252), Expect = e-141 Identities = 252/252 (100%) Strand = Pl...cttaacct 743 Score = 317 bits (160), Expect = 2e-86 Identities = 160/160 (100%) Strand...re = 226 bits (114), Expect = 5e-59 Identities = 114/114 (100%) Strand = Plus / Plus Query: 776 taaatgataatc...), Expect = 6e-46 Identities = 92/92 (100%) Strand = Plus / Plus Query: 979 gataacaatggttcttcaggtggaggatttaa

  8. HOME Rent Limits

    Data.gov (United States)

    Department of Housing and Urban Development — In accordance with 24 CFR Part 92.252, HUD provides maximum HOME rent limits. The maximum HOME rents are the lesser of: The fair market rent for existing housing...

  9. Dicty_cDB: Contig-U13016-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available tntgntg 72 Query: 73 atttngatccnaaaccnttcntttgtaaaactgcngctgntgtttcngttggngttgctg 132 ||||||||||||||||||||||...|||||||||||||||||||||||||||||||||||||| Sbjct: 73 atttngatccnaaaccnttcntttgtaaaactgcngctgntgtttcngttggngttgct...gtntttatttttgnnggnaanaaag 192 Query: 193 gttatgacttntggaaancnagtcaaggngntncnatggccccntcnaatgccnatcccc 252 ||...|||||||||||||||||||||||||||||||||||||||||||||||||||||||||| Sbjct: 193 gttatgacttntggaaancnagtcaaggngntncnatggccccntcnaatgccna...e-30 Identities = 165/186 (88%) Strand = Plus / Plus Query: 71 tgatttngatccnaaaccnttcntttgtaaaactgcngctgntgt

  10. Designing Learning Networks for Lifelong Learners

    NARCIS (Netherlands)

    Koper, Rob

    2005-01-01

    Koper, R. (2005). Designing Learning Networks for Lifelong Learners. In: Koper, R. & Tattersall, C., Learning Design: A Handbook on Modelling and Delivering Networked Education and Training (pp. 239-252). Berlin-Heidelberg: Springer Verlag.

  11. Data of evolutionary structure change: 1MBQA-2TGDA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1MBQA-2TGDA 1MBQ 2TGD A A IVGGYECKAYSQPHQVSLNSGYHFCGGSLVNENWVVSAA...CNNSYPGMITNAMFCAGYLEGGKDSCQGDSGGPVVCNGELQGVVSWGYGCAEPGNPGVYAKVCIFNDWLTSTMA-- -VGGYTCGANTVPYQVSL...VASISLPTSCASAGTQCLISGWGNTKSSGTSYPDVLKCLKAPILSDSSCKSAYPGQITSNMFCAGYLEGGKDSCQGDSGGPVVCSGKLQGIVSWGSGCAQKNKPGVYT...P CA 252 LYS CA 335 ASN CA 345 2TGD... A 2TGDA NTK

  12. Ten-Competence: Life-Long Competence Development and Learning

    NARCIS (Netherlands)

    Koper, Rob; Specht, Marcus

    2006-01-01

    Koper, R., & Specht, M. (2008). Ten-Competence: Life-Long Competence Development and Learning. In M-A. Cicilia (Ed.), Competencies in Organizational e-learning: concepts and tools (pp. 234-252). Hershey: IGI-Global.

  13. Proceedings of the First Environmental Physics Conference (EPC-2004)

    International Nuclear Information System (INIS)

    The publication has been set up as proceedings of the environmental physics conference. the conference consistes of environmental monitoring, the Eco system, natural radioactivity, hazards and risks, activity reviews, environmental mangement. this conference consistes of 252p., figs., tabs., refrs

  14. 77 FR 20688 - 29th Meeting: RTCA Special Committee 206, Aeronautical Information and Meteorological Data Link...

    Science.gov (United States)

    2012-04-05

    ... Status. Discuss previously proposed TOR changes and DO-252 Revision. Discuss TOR changes for the June PMC... release to the PMC. Agree upon TOR changes for June PMC meeting. Other business. Adjourn--1...

  15. AcEST: BP920729 [AcEST

    Lifescience Database Archive (English)

    Full Text Available SPSWMGREGSNNNVQGPKSKKASPRREDLYSKSN-FTAVSN 252 K+ S+P + KSSS+E + N+ + KK S ++ L SK N ++ Sbjct: 352 KELESIPTVEDKSSSVEEEINNINSHINE...+D Sbjct: 4899 SIPTVEDKSSELENEINNINSHINEKNSKNAEQEKKNSELQQQLESKKNELESIPTVEDK 4958 Query: 239 SKELEKAI--LNAQIG

  16. Subroutines to Simulate Fission Neutrons for Monte Carlo Transport Codes

    CERN Document Server

    Lestone, J P

    2014-01-01

    Fortran subroutines have been written to simulate the production of fission neutrons from the spontaneous fission of 252Cf and 240Pu, and from the thermal neutron induced fission of 239Pu and 235U. The names of these four subroutines are getnv252, getnv240, getnv239, and getnv235, respectively. These subroutines reproduce measured first, second, and third moments of the neutron multiplicity distributions, measured neutron-fission correlation data for the spontaneous fission of 252Cf, and measured neutron-neutron correlation data for both the spontaneous fission of 252Cf and the thermal neutron induced fission of 235U. The codes presented here can be used to study the possible uses of neutron-neutron correlations in the area of transparency measurements and the uses of neutron-neutron correlations in coincidence neutron imaging.

  17. 48 CFR 247.572 - Policy.

    Science.gov (United States)

    2010-10-01

    ...) DoD contractors must transport supplies, as defined in the clause at 252.247-7023, Transportation of... Army determines that the proposed freight charges are excessive or unreasonable in accordance with...

  18. PGNAA neutron source moderation setup optimization

    OpenAIRE

    Zhang, Jinzhao; Tuo, Xianguo

    2013-01-01

    Monte Carlo simulations were carried out to design a prompt {\\gamma}-ray neutron activation analysis (PGNAA) thermal neutron output setup using MCNP5 computer code. In these simulations the moderator materials, reflective materials and structure of the PGNAA 252Cf neutrons of thermal neutron output setup were optimized. Results of the calcuations revealed that the thin layer paraffin and the thick layer of heavy water moderated effect is best for 252Cf neutrons spectrum. The new design compar...

  19. The establishment, nurturing, and fruition of a national transplutonium production program

    International Nuclear Information System (INIS)

    The first two slides describe the discovery of 252Cf and the properties that make it useful as a neutron source. The next two describe the applications. The next two cover the history of the Market Development Program, which is pretty much phased out now, with most residual responsibilities transferred to Oak Ridge. The final slide illustrates the uses of 252Cf that has been sold and commercially fabricated into neutron sources

  20. Minor Actinide Burning in Thermal Reactors. A Report by the Working Party on Scientific Issues of Reactor Systems

    International Nuclear Information System (INIS)

    The actinides (or actinoids) are those elements in the periodic table from actinium upwards. Uranium (U) and plutonium (Pu) are two of the principal elements in nuclear fuel that could be classed as major actinides. The minor actinides are normally taken to be the triad of neptunium (Np), americium (Am) and curium (Cm). The combined masses of the remaining actinides (i.e. actinium, thorium, protactinium, berkelium, californium, einsteinium and fermium) are small enough to be regarded as very minor trace contaminants in nuclear fuel. Those elements above uranium in the periodic table are known collectively as the transuranics (TRUs). The operation of a nuclear reactor produces large quantities of irradiated fuel (sometimes referred to as spent fuel), which is either stored prior to eventual deep geological disposal or reprocessed to enable actinide recycling. A modern light water reactor (LWR) of 1 GWe capacity will typically discharge about 20-25 tonnes of irradiated fuel per year of operation. About 93-94% of the mass of uranium oxide irradiated fuel is comprised of uranium (mostly 238U), with about 4-5% fission products and ∼1% plutonium. About 0.1-0.2% of the mass is comprised of neptunium, americium and curium. These latter elements accumulate in nuclear fuel because of neutron captures, and they contribute significantly to decay heat loading and neutron output, as well as to the overall radio-toxic hazard of spent fuel. Although the total minor actinide mass is relatively small - approximately 20-25 kg per year from a 1 GWe LWR - it has a disproportionate impact on spent fuel disposal, and thus the longstanding interest in transmuting these actinides either by fission (to fission products) or neutron capture in order to reduce their impact on the back end of the fuel cycle. The combined masses of the trace actinides actinium, thorium, protactinium, berkelium and californium in irradiated LWR fuel are only about 2 parts per billion, which is far too low for