WorldWideScience

Sample records for chemical enrichment patterns

  1. Silica Retention and Enrichment in Open-System Chemical Weathering on Mars

    Science.gov (United States)

    Yen, A. S.; Ming, D. W.; Gellert, R.; Clark, B. C.; Mittlefehldt, D. W.; Morris, R. V.; Thompson, L. M.; Berger, J.

    2015-01-01

    Chemical signatures of weathering are evident in the Alpha Particle X-ray Spectrometer (APXS) datasets from Gusev Crater, Meridiani Planum, and Gale Crater. Comparisons across the landing sites show consistent patterns indicating silica retention and/or enrichment in open-system aqueous alteration.

  2. Energy consumption of chemical uranium enrichment

    International Nuclear Information System (INIS)

    Miyake, T.; Takeda, K.; Obanawa, H.

    1987-01-01

    A quantitative study of chemical separation energy for enriching uranium-235 by the redox chromatography was conducted. Isotope exchange reactions between U 4+ -UO 2 2+ ions in the enrichment column are maintained by the redox reactions. The chemical separation energy is ultimately supplied by hydrogen and oxygen gas for regenerating redox agents. The redox energy for the isotope separation is theoretically predicted as a function of the dynamic enrichment factor observed in the chromatographic development of uranium adsorption band. Thermodynamic treatments of the equilibrium reactions implies and inverse redox reaction which can be enhanced by the chemical potential of the ion-exchange reaction of oxidant. Experimental results showed 30 to 90% recovery of the redox energy by the inverse reaction. These results will devise a simplified redox chromatography process where a number of columns in one module is reduced

  3. A view of the H-band light-element chemical patterns in globular clusters under the AGB self-enrichment scenario

    Science.gov (United States)

    Dell'Agli, F.; García-Hernández, D. A.; Ventura, P.; Mészáros, Sz; Masseron, T.; Fernández-Trincado, J. G.; Tang, B.; Shetrone, M.; Zamora, O.; Lucatello, S.

    2018-04-01

    We discuss the self-enrichment scenario by asymptotic giant branch (AGB) stars for the formation of multiple populations in globular clusters (GCs) by analysing data set of giant stars observed in nine Galactic GCs, covering a wide range of metallicities and for which the simultaneous measurements of C, N, O, Mg, Al, and Si are available. To this aim, we calculated six sets of AGB models, with the same chemical composition as the stars belonging to the first generation of each GC. We find that the AGB yields can reproduce the set of observations available, not only in terms of the degree of contamination shown by stars in each GC but, more important, also the observed trend with metallicity, which agrees well with the predictions from AGB evolution modelling. While further observational evidences are required to definitively fix the main actors in the pollution of the interstellar medium from which new generation of stars formed in GCs, the present results confirm that the gas ejected by stars of mass in the range 4 M_{⊙} ≤ M ≤ 8 M_{⊙} during the AGB phase share the same chemical patterns traced by stars in GCs.

  4. Neuron-Enriched Gene Expression Patterns are Regionally Anti-Correlated with Oligodendrocyte-Enriched Patterns in the Adult Mouse and Human Brain.

    Science.gov (United States)

    Tan, Powell Patrick Cheng; French, Leon; Pavlidis, Paul

    2013-01-01

    An important goal in neuroscience is to understand gene expression patterns in the brain. The recent availability of comprehensive and detailed expression atlases for mouse and human creates opportunities to discover global patterns and perform cross-species comparisons. Recently we reported that the major source of variation in gene transcript expression in the adult normal mouse brain can be parsimoniously explained as reflecting regional variation in glia to neuron ratios, and is correlated with degree of connectivity and location in the brain along the anterior-posterior axis. Here we extend this investigation to two gene expression assays of adult normal human brains that consisted of over 300 brain region samples, and perform comparative analyses of brain-wide expression patterns to the mouse. We performed principal components analysis (PCA) on the regional gene expression of the adult human brain to identify the expression pattern that has the largest variance. As in the mouse, we observed that the first principal component is composed of two anti-correlated patterns enriched in oligodendrocyte and neuron markers respectively. However, we also observed interesting discordant patterns between the two species. For example, a few mouse neuron markers show expression patterns that are more correlated with the human oligodendrocyte-enriched pattern and vice-versa. In conclusion, our work provides insights into human brain function and evolution by probing global relationships between regional cell type marker expression patterns in the human and mouse brain.

  5. Early history of chemical exchange isotope enrichment and lessons we learn

    International Nuclear Information System (INIS)

    Ishida, Takanobu; Ono, Yuriko

    2006-01-01

    The chemical exchange isotope enrichment process has an advantage over other isotope separation methods in that it involves two chemicals rather than one and, consequently, relatively large separation factors can be obtained. However, the chemical exchange method requires a chemical conversion of the substance enriched in the target isotope into the second substance. The idiosyncrasies of the isotope separation process by this method are pointed out using McCabe-Thiele diagram and, from them, the difficulties involved in the chemical exchange methods are itemized. Examples of the points being made are taken from the pioneering works of this field carried out by Harold C. Urey, his contemporaries, the students and the students' students. Lessons we learn from these works are discussed. (author)

  6. Enrichment of 15N and 10B isotopes by chemical exchange process

    International Nuclear Information System (INIS)

    D'Souza, A.B.; Sonwalkar, A.S.; Subrahmanyam, B.V.; Valladares, B.A.

    1994-01-01

    Many processes are available for separation of stable isotopes like distillation, chemical exchange, thermal diffusion, gaseous diffusion, centrifuge etc. Chemical exchange process is eminently suitable for separation of isotopes of light elements. Work done on separation and enrichment of two of the stable isotopes viz. 15 N and 10 B in Chemical Engineering Division is presented. 15 N is widely used as a tracer in agricultural research and 10 B is used in nuclear industry as control rod material, soluble reactor poison, neutron detector etc. The work on 15 N isotope resulted in a pilot plant, which was the only source of this material in the country for many years and later it was translated into a production plant as M/s. RCF Ltd. The work done on the ion-exchange process for enrichment of 10 B isotope which is basically a chemical exchange process, is now being updated into a pilot plant to produce enriched 10 B to be used as soluble reactor poison. (author)

  7. Interactive design of generic chemical patterns.

    Science.gov (United States)

    Schomburg, Karen T; Wetzer, Lars; Rarey, Matthias

    2013-07-01

    Every medicinal chemist has to create chemical patterns occasionally for querying databases, applying filters or describing functional groups. However, the representations of chemical patterns have been so far limited to languages with highly complex syntax, handicapping the application of patterns. Graphic pattern editors similar to chemical editors can facilitate the work with patterns. In this article, we review the interfaces of frequently used web search engines for chemical patterns. We take a look at pattern editing concepts of standalone chemical editors and finally present a completely new, unpublished graphical approach to pattern design, the SMARTSeditor. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. The changing pattern of the Western world enrichment industry

    International Nuclear Information System (INIS)

    Paleit, J.A.

    1988-01-01

    Past and future changes in the long-term enrichment market of the Western world are discussed, mainly from an economic point of view. Major trends and issues are summarized in the following subjects: an abstract economic model of market forms; factors specific to the enrichment market for defining its overall place within the economic model; a description of the changing pattern (market forms) of the Western world enrichment market and its major regional components in the period 1973-95 (one of the last years of the US world-wide monopoly, and one of the last years of contracts concluded in the early 1970s, respectively); a commentary, on the basis of four 'perfect market' criteria, on the main factors influencing these changes; an outlook on the market in the year 2000. (author)

  9. Enrichment of {sup 15}N and {sup 10}B isotopes by chemical exchange process

    Energy Technology Data Exchange (ETDEWEB)

    D` Souza, A B; Sonwalkar, A S; Subrahmanyam, B V; Valladares, B A [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Many processes are available for separation of stable isotopes like distillation, chemical exchange, thermal diffusion, gaseous diffusion, centrifuge etc. Chemical exchange process is eminently suitable for separation of isotopes of light elements. Work done on separation and enrichment of two of the stable isotopes viz. {sup 15}N and {sup 10}B in Chemical Engineering Division is presented. {sup 15}N is widely used as a tracer in agricultural research and {sup 10}B is used in nuclear industry as control rod material, soluble reactor poison, neutron detector etc. The work on {sup 15}N isotope resulted in a pilot plant, which was the only source of this material in the country for many years and later it was translated into a production plant as M/s. RCF Ltd. The work done on the ion-exchange process for enrichment of {sup 10}B isotope which is basically a chemical exchange process, is now being updated into a pilot plant to produce enriched {sup 10}B to be used as soluble reactor poison. (author). 5 refs., 2 figs., 3 tabs.

  10. Current status of uranium enrichment by way of chemical exchange reactions

    International Nuclear Information System (INIS)

    El Basyouny, A.; Bechthold, H.C.; Knoechel, A.; Vollmer, H.J.

    1985-04-01

    For this report, conference proceedings, patents and other types of literature have been collected to present an account of the current status of uranium enrichment by way of chemical exchange reactions. The report further presents a new concept along with the relevant process strategy developed by the authors. The principal process of the new concept is a chemical exchange process with crown ethers, complexed or free, playing an important part in the reactions. The authors also describe their experiments carried out for establishing suitable chemical systems. (orig./PW) [de

  11. Detection of interstellar DNC - Difficulties of chemical equilibrium hypothesis for enrichment

    Science.gov (United States)

    Godfrey, P. D.; Brown, R. D.; Gunn, H. I.; Blackman, G. L.; Storey, J. W. V.

    1977-01-01

    The J = 1-0 transition of DNC at 76.3058 GHz has been observed in emission in NGC 2264. Comparison with previous observations of HN(C-13) indicates that deuterium is enriched in DNC similarly to the enrichment reported for DCO(+) in this source. The DNC/HNC ratio is estimated to be about 1/24. The results cannot readily be interpreted in terms of chemical equilibria relating to the formation of DNC. It is suggested that the explanation must be sought in isotope effects on rates of formation of interstellar molecules.

  12. Atypical Mg-poor Milky Way Field Stars with Globular Cluster Second-generation-like Chemical Patterns

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Trincado, J. G.; Geisler, D.; Tang, B.; Villanova, S.; Mennickent, R. E. [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Zamora, O.; García-Hernández, D. A.; Dell’Agli, F.; Prieto, Carlos Allende [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Souto, Diogo; Cunha, Katia [Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400 (Brazil); Schiavon, R. P. [Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Hasselquist, Sten [New Mexico State University, Las Cruces, NM 88003 (United States); Shetrone, M. [University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734 (United States); Vieira, K. [Centro de Investigaciones de Astronomía, AP 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Zasowski, G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Sobeck, J.; Hayes, C. R.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States); Placco, V. M., E-mail: jfernandezt@astro-udec.cl, E-mail: jfernandezt87@gmail.com [Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States); and others

    2017-09-01

    We report the peculiar chemical abundance patterns of 11 atypical Milky Way (MW) field red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). These atypical giants exhibit strong Al and N enhancements accompanied by C and Mg depletions, strikingly similar to those observed in the so-called second-generation (SG) stars of globular clusters (GCs). Remarkably, we find low Mg abundances ([Mg/Fe] < 0.0) together with strong Al and N overabundances in the majority (5/7) of the metal-rich ([Fe/H] ≳ −1.0) sample stars, which is at odds with actual observations of SG stars in Galactic GCs of similar metallicities. This chemical pattern is unique and unprecedented among MW stars, posing urgent questions about its origin. These atypical stars could be former SG stars of dissolved GCs formed with intrinsically lower abundances of Mg and enriched Al (subsequently self-polluted by massive AGB stars) or the result of exotic binary systems. We speculate that the stars Mg-deficiency as well as the orbital properties suggest that they could have an extragalactic origin. This discovery should guide future dedicated spectroscopic searches of atypical stellar chemical patterns in our Galaxy, a fundamental step forward to understanding the Galactic formation and evolution.

  13. Laboratory studies of 235U enrichment by chemical separation methods

    International Nuclear Information System (INIS)

    Daloisi, P.J.; Orlett, M.J.; Tracy, J.W.; Saraceno, A.J.

    1976-01-01

    Laboratory experiments on 235 U enrichment processes based on column redox ion exchange, electrodialysis, and gas exchange chromatography performed from August 1972 to September 1974 are summarized. Effluent from a 50 to 50 weight mixture of U +4 and U +6 (as UO 2 2+ ), at a total uranium concentration of 5 mg U per ml in 0.25N H 2 SO 4 -0.03N NaF solution, passing through a 100 cm length cation exchange column at 0.5 ml/min flow rates, was enriched in 235 U by 1.00090 +- .00012. The enriched fraction was mostly in the +6 valence form while the depleted fraction was U +4 retained on the resin. At flow rates of 2 ml/min, the enrichment factor decreases to 1.00033 +- .00003. In the electrodialysis experiments, the fraction of uranium diffusing through the membranes (mostly as +6 valence state) in 4.2 hours is enriched in 235 U by 1.00096 +- .00012. Gas exchange chromatography tests involved dynamic and static exposure of UF 6 over NaF. In dynamic tests, no significant change in isotopic abundance occurred in the initial one-half weight cut of UF 6 . The measured relative 235 U/ 238 U mole ratios were 1.00004 +- .00004 for these runs. In static runs, enrichment became evident. For the NaF(UF 6 )/sub x/-UF 6 system, there is 235 U depletion in the gas phase, with a single-stage factor of 1.00033 at 100 0 C and 1.00025 at 25 0 C after 10 days of equilibration. The single-stage or unit holdup time is impractically long for all three chemical processes

  14. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    Science.gov (United States)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  15. Enrichment: CRISLA [chemical reaction by isotope selective activation] aims to reduce costs

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1989-01-01

    Every year, more than $3 billion is spent on enriching uranium. CRISLA (Chemical Reaction by Isotope Selective Activation) uses a laser-catalyzed chemical reaction which, its proponents claim, could substantially reduce these costs. In CRISLA, an infrared CO laser illuminates the intracavity reaction cell (IC) at a frequency tuned to excite primarily UF 6 . When UF 6 and co-reactant RX are passed through the IC, the tuned laser photons preferentially enhance the reaction of UF 6 with RX ten-thousand-fold over the thermal reaction rate. Thus the laser serves as an activator and the chemical energy for separation is largely chemical. (author)

  16. Chemical enrichment in halo planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Peimbert, S; Rayo, J F; Peimbert, M [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    Photoelectric spectrophotometry of emission lines in the 3400-7400 A region is presented for the planetary nebulae 108-76/sup 0/1(BB1). From these observations the relative abundances of H, He, C, N, O and Ne are derived. The abundances of the halo PN (BB1, H4-1 and K648) are compared to those predicted by stellar evolution theory under the assumption that the envelope has the chemical composition of the matter located between the H burning shell and the surface. The observed He/H and C/O values are higher than predicted which implies that halo PN contain matter from deeper layers than the H burning shell. Furthermore, the O/Ar, N/Ar and Ne/Ar values in halo PN are higher than in the solar neighbourhood, at least part of this enrichment is produced by the PN progenitors.

  17. Influence of social upbringing on the activity pattern of captive lion Panthera leo cubs: Benefits of behavior enrichment

    Directory of Open Access Journals (Sweden)

    Sibonokuhle NCUBE, Hilton Garikai Taambuka NDAGURWA

    2010-08-01

    Full Text Available The influence of social upbringing on the activity pattern of lion Panthera leo cubs was investigated at three sites. In this study, stimulus objects such as sticks, grass, fresh dung (elephant Loxondota africana, zebra Equus quagga, impala Aepyceros melampus, duiker Sylvicapra grimmia, kudu Tragelaphus strepsiceros, giraffe Giraffa camelopardalis and wildebeest Connochaetes taurinus and cardboard boxes, were utilized in an enrichment program aimed at encouraging active behaviors of captive lion cubs at Antelope Park and Masuwe. Lion cubs at Chipangali were not behaviorally enriched. Activity patterns were recorded for 10 days at each site. We recorded moving, resting, playing, grooming, visual exploration and display of hunting instincts. We found that behavioral enrichment enhanced the active behaviors of captive lion cubs. Orphan-raised cubs spent more time moving, playing and displaying hunting instincts than mother-raised cubs, but the time spent grooming was similar across areas and suggests that grooming is not influenced by enrichment. Mother-raised cubs spent more time engaged in visual exploration than orphan-raised cubs and this could be a behavior acquired from mothers or a result of confidence to explore because of their presence. Activity patterns were different among time treatments across our three study sites. Based on these findings, we suggest that lion cubs raised in captivity could benefit from behavioral enrichment to encourage active behaviors essential for eventual reintroduction into the wild [Current Zoology 56 (4: 389–394, 2010].

  18. Multi-layer solid-phase extraction and evaporation-enrichment methods for polar organic chemicals from aqueous matrices.

    Science.gov (United States)

    Köke, Niklas; Zahn, Daniel; Knepper, Thomas P; Frömel, Tobias

    2018-03-01

    Analysis of polar organic chemicals in the aquatic environment is exacerbated by the lack of suitable and widely applicable enrichment methods. In this work, we assessed the suitability of a novel combination of well-known solid-phase extraction (SPE) materials in one cartridge as well as an evaporation method and for the enrichment of 26 polar model substances (predominantly log D evaporation method were investigated for the recovery and matrix effects of the model substances and analyzed with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). In total, 65% of the model substances were amenable (> 10% recovery) to the mlSPE method with a mean recovery of 76% while 73% of the model substances were enriched with the evaporation method achieving a mean recovery of 78%. Target and non-target screening comparison of both methods with a frequently used reversed-phase SPE method utilizing "hydrophilic and lipophilic balanced" (HLB) material was performed. Target analysis showed that the mlSPE and evaporation method have pronounced advantages over the HLB method since the HLB material retained only 30% of the model substances. Non-target screening of a ground water sample with the investigated enrichment methods showed that the median retention time of all detected features on a HILIC system decreased in the order mlSPE (3641 features, median t R 9.7 min), evaporation (1391, 9.3 min), HLB (4414, 7.2 min), indicating a higher potential of the described methods to enrich polar analytes from water compared with HLB-SPE. Graphical abstract Schematic of the method evaluation (recovery and matrix effects) and method comparison (target and non-target analysis) of the two investigated enrichment methods for very polar chemicals in aqueousmatrices.

  19. Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R{sub 200}

    Energy Technology Data Exchange (ETDEWEB)

    Ezer, Cemile; Ercan, E. Nihal [Department of Physics, Boğaziçi University, Istanbul (Turkey); Bulbul, Esra; Bautz, Mark W.; McDonald, Mike; Miller, Eric D. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Smith, Randall K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Loewenstein, Mike, E-mail: cemile.ezer@boun.edu.tr [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2017-02-10

    The spatial distribution of the metals residing in the intra-cluster medium (ICM) of galaxy clusters records all the information on a cluster’s nucleosynthesis and chemical enrichment history. We present measurements from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out to its virial radius (∼1470 kpc). We find that the ratio of the observed supernova type Ia explosions to the total supernova explosions has a uniform distribution at a level of 12%–16% out to the cluster’s virial radius. The observed fraction of type Ia supernova explosions is in agreement with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the ICM in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during a period of intense star formation activity. Additionally, we find that the 2D delayed detonation model CDDT produce significantly worse fits to the X-ray spectra compared to simple 1D W7 models. This is due to the relative overestimate of Si, and the underestimate of Mg in these models with respect to the measured abundances.

  20. Chemically Patterned Inverse Opal Created by a Selective Photolysis Modification Process.

    Science.gov (United States)

    Tian, Tian; Gao, Ning; Gu, Chen; Li, Jian; Wang, Hui; Lan, Yue; Yin, Xianpeng; Li, Guangtao

    2015-09-02

    Anisotropic photonic crystal materials have long been pursued for their broad applications. A novel method for creating chemically patterned inverse opals is proposed here. The patterning technique is based on selective photolysis of a photolabile polymer together with postmodification on released amine groups. The patterning method allows regioselective modification within an inverse opal structure, taking advantage of selective chemical reaction. Moreover, combined with the unique signal self-reporting feature of the photonic crystal, the fabricated structure is capable of various applications, including gradient photonic bandgap and dynamic chemical patterns. The proposed method provides the ability to extend the structural and chemical complexity of the photonic crystal, as well as its potential applications.

  1. Discriminative Chemical Patterns: Automatic and Interactive Design.

    Science.gov (United States)

    Bietz, Stefan; Schomburg, Karen T; Hilbig, Matthias; Rarey, Matthias

    2015-08-24

    The classification of molecules with respect to their inhibiting, activating, or toxicological potential constitutes a central aspect in the field of cheminformatics. Often, a discriminative feature is needed to distinguish two different molecule sets. Besides physicochemical properties, substructures and chemical patterns belong to the descriptors most frequently applied for this purpose. As a commonly used example of this descriptor class, SMARTS strings represent a powerful concept for the representation and processing of abstract chemical patterns. While their usage facilitates a convenient way to apply previously derived classification rules on new molecule sets, the manual generation of useful SMARTS patterns remains a complex and time-consuming process. Here, we introduce SMARTSminer, a new algorithm for the automatic derivation of discriminative SMARTS patterns from preclassified molecule sets. Based on a specially adapted subgraph mining algorithm, SMARTSminer identifies structural features that are frequent in only one of the given molecule classes. In comparison to elemental substructures, it also supports the consideration of general and specific SMARTS features. Furthermore, SMARTSminer is integrated into an interactive pattern editor named SMARTSeditor. This allows for an intuitive visualization on the basis of the SMARTSviewer concept as well as interactive adaption and further improvement of the generated patterns. Additionally, a new molecular matching feature provides an immediate feedback on a pattern's matching behavior across the molecule sets. We demonstrate the utility of the SMARTSminer functionality and its integration into the SMARTSeditor software in several different classification scenarios.

  2. The Populations of Carina. II. Chemical Enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Norris, John E.; Yong, David; Casagrande, Luca; Dotter, Aaron [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Venn, Kim A. [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1 (Canada); Gilmore, Gerard, E-mail: jen@mso.anu.edu.au, E-mail: yong@mso.anu.edu.au, E-mail: luca@mso.anu.edu.au, E-mail: aaron.dotter@gmail.com, E-mail: kvenn@uvic.ca, E-mail: gil@ast.cam.ac.uk [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2017-06-01

    Chemical abundances are presented for 19 elements in a sample of 63 red giants in the Carina dwarf spheroidal galaxy (dSph), based on homogeneous 1D/LTE model atmosphere analyses of our own observations (32 stars) and data available in the literature (a further 31 independent stars). The (Fe) metallicity and [ α /Fe] distribution functions have mean values and dispersions of −1.59 and 0.33 dex ([Fe/H] range: −2.68 to −0.64) and 0.07 and 0.13 dex ([ α /Fe] range: −0.27 to 0.25), respectively. We confirm the finding of Venn et al. that a small percentage (some 10% in the present investigation) of the sample shows clear evidence for significant enrichment by Type Ia supernova (SN Ia) ejecta. Calcium, with the most accurately determined abundance of the α -elements, shows an asymmetric distribution toward smaller values of [Ca/Fe] at all [Fe/H], most significantly over −2.0 < [Fe/H] < −1.0, suggestive of incomplete mixing of the ejecta of SNe Ia with the ambient medium of each of Carina’s generations. Approximate color–magnitude diagram age estimates are presented for the sample, and together with our chemical abundances, compared with the results of our previous synthetic color–magnitude diagram analysis, which reported the details of Carina’s four well-defined populations. We searched for the Na–O anticorrelation universally reported in the Galaxy’s globular clusters and confirm that this phenomenon does not exist in Carina. We also found that one of the 32 stars in our sample has an extremely enhanced lithium abundance— A (Li){sub NLTE} = +3.36, consistent with membership of the ∼1% group of Li-rich stars in dSph described by Kirby et al.

  3. Analysis of 235U enrichment by chemical exchange in U(IV) - U(VI) system on anionite

    International Nuclear Information System (INIS)

    Raica, Paula; Axente, Damian

    2007-01-01

    Full text: A theoretical study about the 235 U enrichment by chemical exchange method in U(IV)-U(VI) system on anion-exchange resins is presented. The 235 U isotope concentration profiles along the band were numerically calculated using an accurate mathematical model and simulations were carried out for the situation of product and waste withdrawal and feed supply. By means of numerical simulation, an estimation of the migration time, necessary for a desired enrichment degree, was obtained. The required migration distance, the production of uranium 3 at.% 235 U per year and the plant configuration are calculated for different operating conditions. An analysis of the process scale for various experimental conditions is also presented. (authors)

  4. Uranium enrichment by gas centrifuge

    International Nuclear Information System (INIS)

    Heriot, I.D.

    1988-01-01

    After recalling the physical principles and the techniques of centrifuge enrichment the report describes the centrifuge enrichment programmes of the various countries concerned and compares this technology with other enrichment technologies like gaseous diffusion, laser, aerodynamic devices and chemical processes. The centrifuge enrichment process is said to be able to replace with advantage the existing enrichment facilities in the short and medium term. Future prospects of the process are also described, like recycled uranium enrichment and economic improvements; research and development needs to achieve the economic prospects are also indicated. Finally the report takes note of the positive aspect of centrifuge enrichment as far as safeguards and nuclear safety are concerned. 27 figs, 113 refs

  5. Modeling chemical kinetics of avocado oil ethanolysis catalyzed by solid glycerol-enriched calcium oxide

    International Nuclear Information System (INIS)

    Avhad, M.R.; Sánchez, M.; Bouaid, A.; Martínez, M.; Aracil, J.; Marchetti, J.M.

    2016-01-01

    Highlights: • Raw materials for biodiesel production can be obtained from the natural resources. • The glycerol-enriched CaO catalyst was tested for the ethanolysis of avocado oil. • CaO synthesized through the thermal treatment of Mytilus Galloprovincialis shells. • The ethanol-adsorption step controlled the overall ethanolysis process. • The physico-chemical properties of avocado oil and FAEEs is presented. - Abstract: The catalytic activity of glycerol-enriched calcium oxide for the alcoholysis reaction between avocado oil and ethanol was investigated. The calcium oxide was derived from Mytilus Galloprovincialis shells. This study systematically examined the influence of temperature, ethanol-to-oil molar ratio, and the catalyst amount on the variation in the concentration of triacylglycerols and biodiesel with reaction time. The interaction between the reaction variables (ethanol-to-oil molar ratio and catalyst amount), their influence on the ethanolysis process, and the optimum variables affecting the process were determined through the response surface methodology. A previously developed mathematical model was applied for the current ethanolysis process, and the model parameters were determined. The ethanolysis reaction occurred between the surface chemisorbed ethoxide ions and oil molecules in the liquid phase, while, the overall process was controlled by the ethanol-adsorption step. The physico-chemical properties of biodiesel, produced using potassium methoxide catalyst, were additionally measured.

  6. Evaporation of liquids on chemically patterned surfaces

    NARCIS (Netherlands)

    Vieyra Salas, J.A.; Darhuber, A.A.

    2011-01-01

    We studied evaporation rates of volatile liquids deposited onto chemically patterned surfaces by means of experiments and numerical simulations. We quantified the influence of the droplet geometry, in particular circular, triangular, rectangular and square shapes, as well as the influence of contact

  7. The One-Pot Directed Assembly of Cylinder-Forming Block Copolymer on Adjacent Chemical Patterns for Bimodal Patterning.

    Science.gov (United States)

    Chang, Tzu-Hsuan; Xiong, Shisheng; Liu, Chi-Chun; Liu, Dong; Nealey, Paul F; Ma, Zhenqiang

    2017-09-01

    The direct self-assembly of cylinder-forming poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) block copolymer is successfully assembled into two orientations, according to the underlying guiding pattern in different areas. Lying-down and perpendicular cylinders are formed, respectively, depending on the design of chemical pattern: sparse line/space pattern or hexagonal dot array. The first chemical pattern composed of prepatterned cross-linked polystyrene (XPS) line/space structure has a period (L S ) equal to twice the intercylinder period of the block copolymer (L 0 ). The PS-b-PMMA thin film on the prepared chemical template after thermal annealing forms a lying-down cylinder morphology when the width of the PS strips is less than the width of PS block in the PS-b-PMMA block copolymer. The morphology is only applicable at the discrete thickness of the PS-b-PMMA film. In addition to forming the lying-down cylinders directly on the XPS guiding pattern, the cylinder-forming block copolymer can also be assembled in a perpendicular way on the second guiding pattern (the hexagonal dot array). The block copolymer films are registered into two orientations in a single directed self-assembly process. The features of the assembled patterns are successfully transferred down to the silicon oxide substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Chemical Enrichment and Physical Conditions in IZw18*

    Science.gov (United States)

    Lebouteiller, V.; Heap, S.; Hubeny, I.; Kunth, D.

    2013-01-01

    Low-metallicity star-forming dwarf galaxies are prime targets to understand the chemical enrichment of the interstellar medium. The H I region contains the bulk of the mass in blue compact dwarfs, and it provides important constraints on the dispersal and mixing of heavy elements released by successive star-formation episodes. The metallicity of the H I region is also a critical parameter to investigate the future star-formation history, as metals provide most of the gas cooling that will facilitate and sustain star formation. Aims. Our primary objective is to study the enrichment of the H I region and the interplay between star-formation history and metallicity evolution. Our secondary obje ctive is to constrain the spatial- and time-scales over which the HI and H II regions are enriched, and the mass range of stars responsible for the heavy element production. Finally, we aim to examine the gas heating and cooling mechanisms in the H I region. Methods. We observed the most metal-poor star-forming galaxy in the Local Universe, I Zw 18, with the Cosmic Origin Spectrograph onboard Hubble. The abundances in the neutral gas are derived from far-ultraviolet absorption-lines (H I, CIII, CIIi*, N I, OI,...) and are compared to the abundances in the H II region. Models are constructed to calculate the ionization structure and the thermal processes. We investigate the gas cooling in the HIi region through physical diagnostics drawn from the fine-structure level of C+. Results. We find that H I region abundances are lower by a factor of approx 2 as compared to the H II region. There is no differential depletion on dust between the H I and H II region. Using sulfur as a metallicity tracer, we calculate a metallicity of 1/46 Z(solar) (vs. 1/31 Z(solar) in the H II region). From the study of the C/O, [O/Fe], and N/O abundance ratios, we propose that C, N, O, and Fe are mainly produced in massive stars. We argue that the H I envelope may contain pockets of pristine gas with a

  9. Uranium enrichment. Enrichment processes

    International Nuclear Information System (INIS)

    Alexandre, M.; Quaegebeur, J.P.

    2009-01-01

    Despite the remarkable progresses made in the diversity and the efficiency of the different uranium enrichment processes, only two industrial processes remain today which satisfy all of enriched uranium needs: the gaseous diffusion and the centrifugation. This article describes both processes and some others still at the demonstration or at the laboratory stage of development: 1 - general considerations; 2 - gaseous diffusion: physical principles, implementation, utilisation in the world; 3 - centrifugation: principles, elementary separation factor, flows inside a centrifuge, modeling of separation efficiencies, mechanical design, types of industrial centrifuges, realisation of cascades, main characteristics of the centrifugation process; 4 - aerodynamic processes: vortex process, nozzle process; 5 - chemical exchange separation processes: Japanese ASAHI process, French CHEMEX process; 6 - laser-based processes: SILVA process, SILMO process; 7 - electromagnetic and ionic processes: mass spectrometer and calutron, ion cyclotron resonance, rotating plasmas; 8 - thermal diffusion; 9 - conclusion. (J.S.)

  10. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

    NARCIS (Netherlands)

    Jiang, Y.; Mikova, G.; Kleerebezem, R.; Van der Wielen, L.A.M.; Cuellar Soares, M.C.

    2015-01-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS

  11. A mathematical basis for plant patterning derived from physico-chemical phenomena.

    Science.gov (United States)

    Beleyur, Thejasvi; Abdul Kareem, Valiya Kadavu; Shaji, Anil; Prasad, Kalika

    2013-04-01

    The position of leaves and flowers along the stem axis generates a specific pattern, known as phyllotaxis. A growing body of evidence emerging from recent computational modeling and experimental studies suggests that regulators controlling phyllotaxis are chemical, e.g. the plant growth hormone auxin and its dynamic accumulation pattern by polar auxin transport, and physical, e.g. mechanical properties of the cell. Here we present comprehensive views on how chemical and physical properties of cells regulate the pattern of leaf initiation. We further compare different computational modeling studies to understand their scope in reproducing the observed patterns. Despite a plethora of experimental studies on phyllotaxis, understanding of molecular mechanisms of pattern initiation in plants remains fragmentary. Live imaging of growth dynamics and physicochemical properties at the shoot apex of mutants displaying stable changes from one pattern to another should provide mechanistic insights into organ initiation patterns. Copyright © 2013 WILEY Periodicals, Inc.

  12. FORMATION RATES OF POPULATION III STARS AND CHEMICAL ENRICHMENT OF HALOS DURING THE REIONIZATION ERA

    International Nuclear Information System (INIS)

    Trenti, Michele; Stiavelli, Massimo

    2009-01-01

    The first stars in the universe formed out of pristine primordial gas clouds that were radiatively cooled to a few hundreds of degrees kelvin either via molecular or atomic (Lyman-α) hydrogen lines. This primordial mode of star formation was eventually quenched once radiative and/or chemical (metal enrichment) feedbacks marked the transition to Population II stars. In this paper, we present a model for the formation rate of Population III stars based on Press-Schechter modeling coupled with analytical recipes for gas cooling and radiative feedback. Our model also includes a novel treatment for metal pollution based on self-enrichment due to a previous episode of Population III star formation in progenitor halos. With this model, we derive the star formation history of Population III stars, their contribution to the reionization of the universe and the time of the transition from Population III star formation in minihalos (M ∼ 10 6 M sun , cooled via molecular hydrogen) to that in more massive halos (M ∼> 2 x 10 7 M sun , where atomic hydrogen cooling is also possible). We consider a grid of models highlighting the impact of varying the values for the free parameters used, such as star formation and feedback efficiency. The most critical factor is the assumption that only one Population III star is formed in a halo. In this scenario, metal-free stars contribute only to a minor fraction of the total number of photons required to reionize the universe. In addition, metal-free star formation is primarily located in minihalos, and chemically enriched halos become the dominant locus of star formation very early in the life of the universe-at redshift z ∼ 25-even assuming a modest fraction (0.5%) of enriched gas converted in stars. If instead multiple metal-free stars are allowed to form out of a single halo, then there is an overall boost of Population III star formation, with a consequent significant contribution to the reionizing radiation budget. In addition

  13. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

    NARCIS (Netherlands)

    Jiang, Y.; Mikova, G.; Kleerebezem, R.; van der Wielen, L.A.M.; Cuellar, M.C.

    2015-01-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS

  14. Metal-Poor Stars and the Chemical Enrichment of the Universe

    OpenAIRE

    Frebel, Anna; Norris, John E.

    2011-01-01

    Metal-poor stars hold the key to our understanding of the origin of the elements and the chemical evolution of the Universe. This chapter describes the process of discovery of these rare stars, the manner in which their surface abundances (produced in supernovae and other evolved stars) are determined from the analysis of their spectra, and the interpretation of their abundance patterns to elucidate questions of origin and evolution. More generally, studies of these stars contribute to other ...

  15. Development of the chemical decontamination process of uranium enrichment gas centrifuges

    International Nuclear Information System (INIS)

    Mita, Yutaka; Endo, Yuji; Yamanaka, Toshihiro; Oohashi, Yusuke

    2002-01-01

    In Ningyo-Toge Environmental Engineering Center, many of the centrifuges that were tested for uranium enrichment are kept in storage. In the future, it will be necessary to dispose of them properly. By categorizing these centrifuges as 'items that are not required to be treated as radioactive waste', chemical decontamination tests were conducted with the wet process (diluted sulfuric acid) to reduce the amount of such radioactive waste. As a result, concerning the rotors, the assumed radioactive level was attained as items that are not required to be treated as radioactive waste', but the effectiveness of the casings varied. As a future subject, in order to find the optimal decontamination process, the basic test shall be conducted continuously. By taking economical efficiency and the processing time into consideration, the decontamination process will be evaluated and a rational method examined. (author)

  16. Patterning characteristics of a chemically-amplified negative resist in synchrotron radiation lithography

    International Nuclear Information System (INIS)

    Deguchi, Kimiyoshi; Miyoshi, Kazunori; Ishii, Tetsuyoshi; Matsuda, Tadahito

    1992-01-01

    To explore the applicability of synchrotron radiation X-ray lithography for fabricating sub-quartermicron devices, we investigate the patterning characteristics of the chemically-amplified negative resist SAL601-ER7. Since these characteristics depend strongly on the conditions of the chemical amplification process, the effects of post-exposure baking and developing conditions on sensitivity and resolution are examined. The resolution-limiting factors are investigated, revealing that pattern collapse during the development process and fog caused by Fresnel diffraction, photo-electron scattering, and acid diffusion in the resist determine the resolution and the maximum aspect ratio of the lines and spaces pattern. Using the model of a swaying beam supported at one end, it is shown that pattern collapse depends on the resist pattern's flexural stiffness. Patterning stability, which depends on the delay time between exposure and baking, is also discussed. (author)

  17. The advanced CECE process for enriching tritium by the chemical exchange method with a hydrophobic catalyst

    International Nuclear Information System (INIS)

    Kitamoto, Asashi; Shimizu, Masami; Masui, Takashi.

    1992-01-01

    The monothermal chemical exchange process with electrolysis, i.e., CECE process, was an effective method for enriching and removing tritium from tritiated water with low to middle level activity. The purpose of this study is to propose the theoretical background of the two-parameter evaluation method, which is based on a two-step isotope exchange reaction between hydrogen gas and liquid water, for improvement of the performance of a hydrophobic catalyst by a trickle bed-type column. Finally, a two-parameter method could attain the highest performance of isotope separation and the lowest liquid holdup for a trickle bed-type column. Therefore, this method will present some effective and practical procedures in scaling up a tritium enrichment process. The main aspect of the CECE process in engineering design and system evaluation was to develop the isotope exchange column with a high performance catalyst. (author)

  18. Kinetics of directed self-assembly of block copolymers on chemically patterned substrates

    International Nuclear Information System (INIS)

    Müller, Marcus; Li, Weihua; Rey, Juan Carlos Orozco; Welling, Ulrich

    2015-01-01

    Chemically patterned surfaces have been successfully employed to direct the kinetics of self-assembly of block copolymers into dense, periodic morphologies (”chemoepitaxy”). Significant efforts have been directed towards understanding the kinetics of structure formation and, particularly, the formation and annihilation of defects. In the present manuscript we use computer simulations of a soft, coarse-grained polymer model to study the kinetics of structure formation of lamellar-forming block copolymer thin films on a chemical pattern of lines and spaces. The case where the copolymer material replicates the surface pattern and the more subtle scenario of sparse guiding patterns are considered. Our simulation results highlight (1) the importance of the early stages of pattern-directed self-assembly that template the subsequent morphology and (2) the dependence of the free-energy landscape on the incompatibility between the two blocks of the copolymer. (paper)

  19. Bifunctional, Chemically Patterned Flat Stamps for Microcontact Printing of Polar Inks

    NARCIS (Netherlands)

    Duan, X.; Sadhu, V.B.; Perl, A.; Péter, M.; Reinhoudt, David; Huskens, Jurriaan

    2008-01-01

    Different methods to create chemically patterned, flat PDMS stamps with two different chemical functionalities were compared. The best method for making such stamps, functionalized with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFDTS) and 3-(aminopropyl)triethoxysilane (APTS), appeared to be full

  20. Reversible chemical patterning on stimuli-responsive polymer film: Environment-responsive lithography

    International Nuclear Information System (INIS)

    Ionov, Leonid; Minko, Sergiy; Stamm, Manfred; Gohy, Jean-Francois; Jerome, Robert; Scholl, Andreas

    2003-01-01

    We report on a novel type of chemical patterning based on thin stimuli-responsive polymer films. The basic concept is the permanent storage (writing) of a pattern, which is reversibly developed and erased upon exposure to appropriate environment, e.g., solvent, pH, and temperature. The smart surface is fabricated from the mixed brush of poly(2-vinylpyridine) and polyisoprene. The mixed brush demonstrates switching behavior upon exposure to different solvents. Cross-linking of polyisoprene via illumination through a photomask results in formation of patterns with suppressed switching. Due to the contrast in switching between illuminated and dark areas, exposure of the smart surface to different solvents causes either reversible formation or erasing of chemical contrast between the illuminated and dark areas. Thus, the pattern surface can very locally attract colloidal particles or can be wetted by water only upon exposure to the special solvent which introduces the contrast between the illuminated and dark areas. Appearance of the patterns indicates particular environment and can be used for local switching of adsorption

  1. INSIGHTS INTO PRE-ENRICHMENT OF STAR CLUSTERS AND SELF-ENRICHMENT OF DWARF GALAXIES FROM THEIR INTRINSIC METALLICITY DISPERSIONS

    International Nuclear Information System (INIS)

    Leaman, Ryan

    2012-01-01

    Star clusters are known to have smaller intrinsic metallicity spreads than dwarf galaxies due to their shorter star formation timescales. Here we use individual spectroscopic [Fe/H] measurements of stars in 19 Local Group dwarf galaxies, 13 Galactic open clusters, and 49 globular clusters to show that star cluster and dwarf galaxy linear metallicity distributions are binomial in form, with all objects showing strong correlations between their mean linear metallicity Z-bar and intrinsic spread in metallicity σ(Z) 2 . A plot of σ(Z) 2 versus Z-bar shows that the correlated relationships are offset for the dwarf galaxies from the star clusters. The common binomial nature of these linear metallicity distributions can be explained with a simple inhomogeneous chemical evolution model, where the star cluster and dwarf galaxy behavior in the σ(Z) 2 - Z-bar diagram is reproduced in terms of the number of enrichment events, covering fraction, and intrinsic size of the enriched regions. The inhomogeneity of the self-enrichment sets the slope for the observed dwarf galaxy σ(Z) 2 - Z-bar correlation. The offset of the star cluster sequence from that of the dwarf galaxies is due to pre-enrichment, and the slope of the star cluster sequence represents the remnant signature of the self-enriched history of their host galaxies. The offset can be used to separate star clusters from dwarf galaxies without a priori knowledge of their luminosity or dynamical mass. The application of the inhomogeneous model to the σ(Z) 2 - Z-bar relationship provides a numerical formalism to connect the self-enrichment and pre-enrichment between star clusters and dwarf galaxies using physically motivated chemical enrichment parameters. Therefore we suggest that the σ(Z) 2 - Z-bar relationship can provide insight into what drives the efficiency of star formation and chemical evolution in galaxies, and is an important prediction for galaxy simulation models to reproduce.

  2. CHEMICAL ABUNDANCE PATTERNS AND THE EARLY ENVIRONMENT OF DWARF GALAXIES

    International Nuclear Information System (INIS)

    Corlies, Lauren; Johnston, Kathryn V.; Bryan, Greg; Tumlinson, Jason

    2013-01-01

    Recent observations suggest that abundance pattern differences exist between low metallicity stars in the Milky Way stellar halo and those in the dwarf satellite galaxies. This paper takes a first look at what role the early environment for pre-galactic star formation might have played in shaping these stellar populations. In particular, we consider whether differences in cross-pollution between the progenitors of the stellar halo and the satellites could help to explain the differences in abundance patterns. Using an N-body simulation, we find that the progenitor halos of the main halo are primarily clustered together at z = 10 while the progenitors of the satellite galaxies remain on the outskirts of this cluster. Next, analytically modeled supernova-driven winds show that main halo progenitors cross-pollute each other more effectively while satellite galaxy progenitors remain more isolated. Thus, inhomogeneous cross-pollution as a result of different high-z spatial locations of each system's progenitors can help to explain observed differences in abundance patterns today. Conversely, these differences are a signature of the inhomogeneity of metal enrichment at early times

  3. The extent of chemically enriched gas around star-forming dwarf galaxies

    Science.gov (United States)

    Johnson, Sean

    2018-01-01

    Supernovae driven winds are often invoked to remove chemically enriched gas from galaxies to match the low metallicities of dwarf galaxies. In such shallow potential wells, outflows may produce massive amounts of enriched halo gas (circum-galactic medium or CGM) and pollute the intergalactic medium (IGM). I will present a survey of the CGM and IGM around 18 star-forming field dwarf galaxies with stellar masses of log M*/M⊙ ≈ 8 ‑ 9 at z ≈ 0.2. Eight of these have CGM probed by quasar absorption spectra at projected distances, d, less than the host virial radius, Rh. Ten are probed at d/Rh = 1 ‑ 3 to study the surrounding IGM. The absorption measurements include neutral hydrogen (H I), the dominant silicon ions for diffuse cool gas (T ∼ 104 K; Si II, Si III, and Si IV), more highly ionized carbon (C IV), and highly ionized oxygen (O VI). The metal absorption from the CGM of the dwarf galaxies is less common and ≈ 4× weaker compared to massive star-forming galaxies though O VI absorption is still common. None of the dwarfs probed at d/Rh = 1 ‑ 3 have definitive metal-line detections. Combining the available silicon ions, we estimate that the cool CGM accounts for only 2 ‑ 6% of the expected silicon budget. CGM absorption from O VI can account for ≈ 8% of the expected oxygen budget. As O VI traces an ion with expected equilibrium ion fractions of 0.2, this highly ionized phase of the CGM may represent a significant metal reservoir even for dwarf galaxies not expected to maintain gravitationally shock heated hot halos.

  4. Distribution patterns and enrichment of lead, zinc and copper in surface sediments of the central Portuguese shelf and upper slope

    NARCIS (Netherlands)

    Jesus, C.C.; de Stigter, H.; Miranda, P.; Oliveira, A.; Rocha, F.

    2013-01-01

    Geographic patterns of Cu, Pb and Zn enrichment on the Lisbon-Setúbal-Sines continental shelf and upper slope (central Portuguese margin) were studied in this paper to gain insight into current pathways of trace metal dispersal. Our study is based on the analysis of elemental concentrations and

  5. Exploring consumer exposure pathways and patterns of use for chemicals in the environment through the Chemical/Product Categories Database

    Science.gov (United States)

    Exploring consumer exposure pathways and patterns of use for chemicals in the environment through the Chemical/Product Categories Database (CPCat) (Presented by: Kathie Dionisio, Sc.D., NERL, US EPA, Research Triangle Park, NC (1/23/2014).

  6. An experimental design method leading to chemical Turing patterns.

    Science.gov (United States)

    Horváth, Judit; Szalai, István; De Kepper, Patrick

    2009-05-08

    Chemical reaction-diffusion patterns often serve as prototypes for pattern formation in living systems, but only two isothermal single-phase reaction systems have produced sustained stationary reaction-diffusion patterns so far. We designed an experimental method to search for additional systems on the basis of three steps: (i) generate spatial bistability by operating autoactivated reactions in open spatial reactors; (ii) use an independent negative-feedback species to produce spatiotemporal oscillations; and (iii) induce a space-scale separation of the activatory and inhibitory processes with a low-mobility complexing agent. We successfully applied this method to a hydrogen-ion autoactivated reaction, the thiourea-iodate-sulfite (TuIS) reaction, and noticeably produced stationary hexagonal arrays of spots and parallel stripes of pH patterns attributed to a Turing bifurcation. This method could be extended to biochemical reactions.

  7. Stable isotope enrichment: Current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1992-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities

  8. Stable isotope enrichment - current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1993-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. (orig.)

  9. Using Star Clusters as Tracers of Star Formation and Chemical Evolution: The Chemical Enrichment History of the Large Magellanic Cloud

    Science.gov (United States)

    Chilingarian, Igor V.; Asa’d, Randa

    2018-05-01

    The star formation (SFH) and chemical enrichment (CEH) histories of Local Group galaxies are traditionally studied by analyzing their resolved stellar populations in a form of color–magnitude diagrams obtained with the Hubble Space Telescope. Star clusters can be studied in integrated light using ground-based telescopes to much larger distances. They represent snapshots of the chemical evolution of their host galaxy at different ages. Here we present a simple theoretical framework for the chemical evolution based on the instantaneous recycling approximation (IRA) model. We infer a CEH from an SFH and vice versa using observational data. We also present a more advanced model for the evolution of individual chemical elements that takes into account the contribution of supernovae type Ia. We demonstrate that ages, iron, and α-element abundances of 15 star clusters derived from the fitting of their integrated optical spectra reliably trace the CEH of the Large Magellanic Cloud obtained from resolved stellar populations in the age range 40 Myr age–metallicity relation. Moreover, the present-day total gas mass of the LMC estimated by the IRA model (6.2× {10}8 {M}ȯ ) matches within uncertainties the observed H I mass corrected for the presence of molecular gas (5.8+/- 0.5× {10}8 {M}ȯ ). We briefly discuss how our approach can be used to study SFHs of galaxies as distant as 10 Mpc at the level of detail that is currently available only in a handful of nearby Milky Way satellites. .

  10. Ultrastructure and electrophoretic protein pattern of a nuclear fraction enriched in interchromatin granule conglomerations

    Energy Technology Data Exchange (ETDEWEB)

    Krzyzowska-Gruca, S.; Zborek, A.; Gruca, S.

    1986-01-01

    Rats were injected with a cytostatic 1-nitro-9/3'-dimethylpropyloamine/acridine.2HCl to induce aggregation of interchromatin granules (IG). The conglomerations of IG were well preserved in isolated liver nuclei and in nuclear structures deprived of chromatin. This feature enabled obtaining a nuclear fraction enriched in IG. The method consisted in extraction of isolated nuclei with a non-ionic detergent and digestion with DNase I in a high ionic strength. Each step of isolation was ultrastructurally monitored using both the routine electron microscopy as well as a preferential staining of IG with bismuth. Presence of spots of tightly packed granules within IG conglomerations in the final fraction like in the nuclei in situ was a good ultrastructural marker of IG. The resulting fraction consisted predominantly of IG conglomerations. Their preferential staining with bismuth was well preserved. Minute amounts of fibrillar material originating from nuclear matrix and residual nuclei could be observed. Protein composition of the fraction enriched in IG was studied by SDS-polyacrylamide gel electrophoresis. After electrotransfer, nitrocellulose filters were fixed with glutaraldehyde and stained with bismuth method in order to identify IG proteins. The results of ultrastructural and cytochemical studies in comparison to electrophoretic protein pattern are discussed.

  11. AEC determines uranium enrichment policy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The Advisory Committee on Uranium Enrichment of the Atomic Energy Commission (AEC) has submitted a report to AEC chairman concerning the promotion of the introduction of advanced material, high performance centrifuges to replace conventional metallic drum centrifuges, and the development of next generation advanced centrifuges. The report also called for the postponement until around 1997 of the decision whether the development should be continued or not on atomic vapor laser isotope separation (AVLIS) and molecular laser isotope separation (MLIS) processes, as well as the virtual freezing of the construction of a chemical process demonstration plant. The report was approved by the AEC chairman in August. The uranium enrichment service market in the world will continue to be characterized by oversupply. The domestic situation of uranium enrichment supply-demand trend, progress of the expansion of Rokkasho enrichment plant, the trend in the development of gas centrifuge process and the basic philosophy of commercializing domestic uranium enrichment are reported. (K.I.)

  12. Uranium enrichment techniques

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

    This article includes an introduction about the isotopes of natural uranium, their existence and the difficulty of the separation between them. Then it goes to the details of a number of methods used to enrich uranium: Gaseous Diffusion method, Electromagnetic method, Jet method, Centrifugal method, Chemical method, Laser method and Plasma method.

  13. Oak Ridge National Laboratory's isotope enrichment program

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.C.

    1997-01-01

    The Isotope Enrichment Program (IEP) at Oak Ridge National Laboratory (ORNL) is responsible for the production and distribution of ∼225 enriched stable isotopes from 50 multi-isotopic elements. In addition, ORNL distributes enriched actinide isotopes and provides extensive physical- and chemical-form processing of enriched isotopes to meet customer requirements. For more than 50 yr, ORNL has been a major provider of enriched isotopes and isotope-related services to research, medical, and industrial institutions throughout the world. Consolidation of the Isotope Distribution Office (IDO), the Isotope Research Materials Laboratory (IRML), and the stable isotope inventories in the Isotope Enrichment Facility (IEF) have improved operational efficiencies and customer services. Recent changes in the IEP have included adopting policies for long-term contracts, which offer program stability and pricing advantages for the customer, and prorated service charges, which greatly improve pricing to the small research users. The former U.S. Department of Energy (DOE) Loan Program has been converted to a lease program, which makes large-quantity or very expensive isotopes available for nondestructive research at a nominal cost. Current efforts are being pursued to improve and expand the isotope separation capabilities as well as the extensive chemical- and physical-form processing that now exists. The IEF's quality management system is ISO 9002 registered and accredited in the United States, Canada, and Europe

  14. Solvent extraction as a method of promoting uranium enrichment by chemical exchange

    International Nuclear Information System (INIS)

    Fathurrachman.

    1995-01-01

    This thesis examines a chemical exchange process for uranium enrichment using solvent extraction. The system selected is the isotope exchange for uranium species in the form of uranous and uranyl chloride complexes. Solvent extraction has been studied before by French workers for this application but little was published on this. Much of this present work is therefore novel. The equilibrium data for the extraction of U(IV) as U 4+ and U(VI) as UO 2 2+ from hydrochloric media into an organic phase containing tri-n-octylamine (TOA) in benzene is given. Benzene is used to prevent third phase formation. In 4 M HCl U(VI) was found to be very soluble in the organic phase but U(IV) was virtually insoluble. Most of the equilibrium data has been correlated by the Langmuir isotherm. This thesis also outlines the methodology that has to be used to design a plant based on this process. (author)

  15. REE enrichment in granite-derived regolith deposits of the southeast United States: Prospective source rocks and accumulation processes

    Science.gov (United States)

    Foley, Nora K.; Ayuso, Robert A.; Simandl, G.J.; Neetz, M.

    2015-01-01

    The Southeastern United States contains numerous anorogenic, or A-type, granites, which constitute promising source rocks for REE-enriched ion adsorption clay deposits due to their inherently high concentrations of REE. These granites have undergone a long history of chemical weathering, resulting in thick granite-derived regoliths, akin to those of South China, which supply virtually all heavy REE and Y, and a significant portion of light REE to global markets. Detailed comparisons of granite regolith profiles formed on the Stewartsville and Striped Rock plutons, and the Robertson River batholith (Virginia) indicate that REE are mobile and can attain grades comparable to those of deposits currently mined in China. A REE-enriched parent, either A-type or I-type (highly fractionated igneous type) granite, is thought to be critical for generating the high concentrations of REE in regolith profiles. One prominent feature we recognize in many granites and mineralized regoliths is the tetrad behaviour displayed in REE chondrite-normalized patterns. Tetrad patterns in granite and regolith result from processes that promote the redistribution, enrichment, and fractionation of REE, such as late- to post- magmatic alteration of granite and silicate hydrolysis in the regolith. Thus, REE patterns showing tetrad effects may be a key for discriminating highly prospective source rocks and regoliths with potential for REE ion adsorption clay deposits.

  16. On the enrichment of low-abundant isotopes of light chemical elements by gas centrifuges

    International Nuclear Information System (INIS)

    Borisevich, V.D.; Morozov, O.E.; Zaozerskiy, Yu.P.; Shmelev, G.M.; Shipilov, Yu.D.

    2000-01-01

    A brief review of the main areas for the application of the isotopes 15 N and 13 C is made. Separation of the nitrogen isotopes in a single gas centrifuge in the form of pure nitrogen, ammonia, and trifluoride of nitrogen as well as the carbon isotopes in the form of carbon dioxide has been studied by means of numerical simulation. The parameters of the centrifugal machine investigated were close to the parameters of the Iguassu machine. The dependence of the efficiency criterion versus the basic parameters of the separation process has been explored in the computational experiments. Comparisons of the calculated results with the experimental data have shown good agreement. The results obtained have demonstrated the possibility of using gas centrifuge technology to enrich successfully the low-abundant isotopes of light chemical elements

  17. Chemically selective soft x-ray patterning of polymers

    International Nuclear Information System (INIS)

    Wang, J.; Stover, H.D.; Hitchcock, A.P.; Tyliszczak, T.

    2007-01-01

    The chemically selective modification of polymer mixtures by monochromated soft X-rays has been explored using the high-brightness fine-focused 50 nm beam of a scanning transmission X-ray microscope. Four different polymer systems were examined: a polymethylmethacrylate (PMMA) polyacrylonitrile (PAN) bilayer film; a PMMA-blend-PAN microphase-separated film; a poly(MMA-co-AN) copolymer film; and a poly(ethyl cyanoacrylate) homopolymer film. A high level of chemically selective modification was achieved for the PMMA/PAN bilayer; in particular, irradiation at 288.45 eV selectively removed the carbonyl group from PMMA while irradiation at 286.80 eV selectively reduced the nitrile group of PAN, even when these irradiations were carried out at the same (x,y) position of the sample. In the last two homogeneous polymer systems, similar amounts of damage to the nitrile and carbonyl groups occurred during irradiation at either 286.80 or 288.45 eV. This is attributed to damage transfer between the C=N and C=O groups mediated by primary electrons, secondary electrons or radical/ionic processes, aided by their close spatial proximity. Although the overall thickness of the bilayer sample at 70 nm is smaller than the lateral line spreading of 100 nm, the interface between the layers appears to effectively block the transport of energy, and hence damage, between the two layers. The origins of the line spreading in homogeneous phases and possible origins of the damage blocking effect of the interface are discussed. To demonstrate chemically selective patterning, high-resolution multi-wavelength patterns were created in the PMMA/PAN bilayer system

  18. Chemical uranium enrichment with ion exchanger

    International Nuclear Information System (INIS)

    Takeda, Kunihiko; Onitsuka, Hatsuki; Obanawa, Heiichiro

    1991-01-01

    The uranium enrichment by using ion-exchange has been studied and developed since 1972. The ion-exchange rate has been improved approx. 3000 times and the electron exchange reaction, which occurs with ion-exchange reaction, was also accelerated with catalyst. Flow disturbance in a ion-exchange column has been fully studied and the value of turbulence has been reduced to 150μm. These results allowed us to design a very fine separation column, in which about 10000 stages can be obtained even when the column is more than 1 m in diameter. In the course of the development, a self-regenerating reaction between the redox agents was discovered and incorporated into the process, and has resulted in a reduction of 70 % in the separation energy requirement. (author)

  19. ELEMENTAL ABUNDANCES AND THEIR IMPLICATIONS FOR THE CHEMICAL ENRICHMENT OF THE BOOeTES I ULTRAFAINT GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Gerard [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Norris, John E.; Yong, David [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia); Monaco, Lorenzo [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago 19 (Chile); Wyse, Rosemary F. G. [Department of Physics and Astronomy, The Johns Hopkins University, 3900 North Charles Street, Baltimore, MD 21218 (United States); Geisler, D., E-mail: gil@ast.cam.ac.uk, E-mail: jen@mso.anu.edu.au, E-mail: yong@mso.anu.edu.au, E-mail: lmonaco@eso.org, E-mail: wyse@pha.jhu.edu, E-mail: dgeisler@astro-udec.cl [Departamento de Astronomia, Universidad de Concepcion (Chile)

    2013-01-20

    We present a double-blind analysis of high-dispersion spectra of seven red giant members of the Booetes I ultrafaint dwarf spheroidal galaxy, complemented with re-analysis of a similar spectrum of an eighth-member star. The stars cover [Fe/H] from -3.7 to -1.9 and include a CEMP-no star with [Fe/H] = -3.33. We conclude from our chemical abundance data that Booetes I has evolved as a self-enriching star-forming system, from essentially primordial initial abundances. This allows us uniquely to investigate the place of CEMP-no stars in a chemically evolving system, in addition to limiting the timescale of star formation. The elemental abundances are formally consistent with a halo-like distribution, with enhanced mean [{alpha}/Fe] and small scatter about the mean. This is in accord with the high-mass stellar initial mass function in this low-stellar-density, low-metallicity system being indistinguishable from the present-day solar neighborhood value. There is a non-significant hint of a decline in [{alpha}/Fe] with [Fe/H]; together with the low scatter, this requires low star formation rates, allowing time for supernova ejecta to be mixed over the large spatial scales of interest. One star has very high [Ti/Fe], but we do not confirm a previously published high value of [Mg/Fe] for another star. We discuss the existence of CEMP-no stars, and the absence of any stars with lower CEMP-no enhancements at higher [Fe/H], a situation that is consistent with knowledge of CEMP-no stars in the Galactic field. We show that this observation requires there be two enrichment paths at very low metallicities: CEMP-no and 'carbon-normal'.

  20. ELEMENTAL ABUNDANCES AND THEIR IMPLICATIONS FOR THE CHEMICAL ENRICHMENT OF THE BOÖTES I ULTRAFAINT GALAXY

    International Nuclear Information System (INIS)

    Gilmore, Gerard; Norris, John E.; Yong, David; Monaco, Lorenzo; Wyse, Rosemary F. G.; Geisler, D.

    2013-01-01

    We present a double-blind analysis of high-dispersion spectra of seven red giant members of the Boötes I ultrafaint dwarf spheroidal galaxy, complemented with re-analysis of a similar spectrum of an eighth-member star. The stars cover [Fe/H] from –3.7 to –1.9 and include a CEMP-no star with [Fe/H] = –3.33. We conclude from our chemical abundance data that Boötes I has evolved as a self-enriching star-forming system, from essentially primordial initial abundances. This allows us uniquely to investigate the place of CEMP-no stars in a chemically evolving system, in addition to limiting the timescale of star formation. The elemental abundances are formally consistent with a halo-like distribution, with enhanced mean [α/Fe] and small scatter about the mean. This is in accord with the high-mass stellar initial mass function in this low-stellar-density, low-metallicity system being indistinguishable from the present-day solar neighborhood value. There is a non-significant hint of a decline in [α/Fe] with [Fe/H]; together with the low scatter, this requires low star formation rates, allowing time for supernova ejecta to be mixed over the large spatial scales of interest. One star has very high [Ti/Fe], but we do not confirm a previously published high value of [Mg/Fe] for another star. We discuss the existence of CEMP-no stars, and the absence of any stars with lower CEMP-no enhancements at higher [Fe/H], a situation that is consistent with knowledge of CEMP-no stars in the Galactic field. We show that this observation requires there be two enrichment paths at very low metallicities: CEMP-no and 'carbon-normal'.

  1. Shape-dependent guidance of active Janus particles by chemically patterned surfaces

    Science.gov (United States)

    Uspal, W. E.; Popescu, M. N.; Tasinkevych, M.; Dietrich, S.

    2018-01-01

    Self-phoretic chemically active Janus particles move by inducing—via non-equilibrium chemical reactions occurring on their surfaces—changes in the chemical composition of the solution in which they are immersed. This process leads to gradients in chemical composition along the surface of the particle, as well as along any nearby boundaries, including solid walls. Chemical gradients along a wall can give rise to chemi-osmosis, i.e., the gradients drive surface flows which, in turn, drive flow in the volume of the solution. This bulk flow couples back to the particle, and thus contributes to its self-motility. Since chemi-osmosis strongly depends on the molecular interactions between the diffusing molecular species and the wall, the response flow induced and experienced by a particle encodes information about any chemical patterning of the wall. Here, we extend previous studies on self-phoresis of a sphere near a chemically patterned wall to the case of particles with rod-like, elongated shape. We focus our analysis on the new phenomenology potentially emerging from the coupling—which is inoperative for a spherical shape—of the elongated particle to the strain rate tensor of the chemi-osmotic flow. Via detailed numerical calculations, we show that the dynamics of a rod-like particle exhibits a novel ‘edge-following’ steady state: the particle translates along the edge of a chemical step at a steady distance from the step and with a steady orientation. Moreover, within a certain range of system parameters, the edge-following state co-exists with a ‘docking’ state (the particle stops at the step, oriented perpendicular to the step edge), i.e., a bistable dynamics occurs. These findings are rationalized as a consequence of the competition between the fluid vorticity and the rate of strain by using analytical theory based on the point-particle approximation which captures quasi-quantitatively the dynamics of the system.

  2. Enrichment situation outside the United States

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Different enrichment technologies are briefly characterized which include gaseous diffusion, which is presently the production mainstay of the United States and France; the gaseous centrifuge which is the production plant for Urenco and the technology for future United States enrichment expansion; the aero-dynamic processes which include the jet nozzle (also known as the Becker process) and the fixed-wall centrifuge (also known as the Helikon process); chemical processes; laser isotope separation processes (also referred to in the literature as LIS); and plasma technology

  3. Contemporary technology of enrichment of kaolins of Angren deposit. II. Removal of impurities and whitening of kaolins: using electrophysical and chemical methods of cleaning

    International Nuclear Information System (INIS)

    Krivorotov, V.F.; Usmanov, ZH.M.; Fridman, A.A.

    2012-01-01

    The contemporary methods of enrichment of Angren kaolins have been described. The electrophoresis and chemical whitening are demonstrated to be the most effective methods of scavenging. Application of ultrasonic dispersion, electrophoresis and chemical whitening methods allows one to obtain kaolin with whiteness ≅ 88% and content of iron oxides ≅ 0.4%. Using such kaolin as a sorbent at de coloration of plant oil have been shown good adsorption properties, meeting the level of world-wide standards for such class of materials. (authors)

  4. Safety criteria of uranium enrichment plants

    International Nuclear Information System (INIS)

    Nardocci, A.C.; Oliveira Neto, J.M. de

    1994-01-01

    The applicability of nuclear reactor safety criteria applied to uranium enrichment plants is discussed, and a new criterion based on the soluble uranium compounds and hexafluoride chemical toxicities is presented. (L.C.J.A.). 21 refs, 4 tabs

  5. Light Rare Earth Elements enrichment in an acidic mine lake (Lusatia, Germany)

    International Nuclear Information System (INIS)

    Bozau, Elke; Leblanc, Marc; Seidel, Jean Luc; Staerk, Hans-Joachim

    2004-01-01

    The distribution of Rare Earth Elements (REE) was investigated in the acidic waters (lake and groundwater) of a lignite mining district (Germany). The Fe- and SO 4 -rich lake water (pH 2.7) displays high REE contents (e.g. La∼70 μg/l, Ce∼160 μg/l) and an enrichment of light REE (LREE) in the NASC normalised pattern. Considering the hydrodynamic model and geochemical data, the lake water composition may be calculated as a mixture of inflowing Quaternary and mining dump groundwaters. The groundwater of the dump aquifer is LREE enriched. Nevertheless, the leachates of dump sediments generally have low REE contents and display flat NASC normalised patterns. However, geochemical differences and REE pattern in undisturbed lignite (LREE enriched pattern and low water soluble REE contents) and the weathered lignite of the dumps (flat REE pattern and high water soluble REE contents) suggest that lignite is probably the main REE source rock for the lake water

  6. Use of enriched 74Se and 77Se in combination with isotope pattern deconvolution to differentiate and determine endogenous and supplemented selenium in lactating rats

    International Nuclear Information System (INIS)

    Gonzalez Iglesias, H.; Fernandez Sanchez, M.L.; Garcia Alonso, J.I.; Sanz-Medel, A.

    2007-01-01

    A quantitative methodology has been developed to differentiate between endogenous and supplemented selenium in lactating rats using two enriched selenium isotopes. Lactating rats were fed for 2 weeks with formula milk containing one enriched Se isotope, 77 Se, as the metabolic tracer. The isotopic composition of selenium in serum and urine samples was then measured by collision cell ICP-MS after the addition of a solution containing another enriched isotope, 74 Se, as quantitation tracer, before analysis. Isotope pattern deconvolution allowed the transformation of measured Se isotopic abundances into concentrations of natural abundance (endogenous) selenium and enriched 77 Se (supplemented) present in the samples. The proposed methodology was validated using serum and urine reference materials spiked with both 77 Se and 74 Se. The obtained results are discussed in terms of selenium exchange and half-life in lactating rats (11-12 days) and selenium levels in serum in comparison with non-supplemented rats and control rats after maternal feeding. (orig.)

  7. Chemical processes for the extreme enrichment of tellurium into marine ferromanganese oxides

    Science.gov (United States)

    Kashiwabara, Teruhiko; Oishi, Yasuko; Sakaguchi, Aya; Sugiyama, Toshiki; Usui, Akira; Takahashi, Yoshio

    2014-04-01

    Tellurium, an element of growing economic importance, is extremely enriched in marine ferromanganese oxides. We investigated the mechanism of this enrichment using a combination of spectroscopic analysis and adsorption/coprecipitation experiments. X-ray Absorption Near-Edge Structure (XANES) analysis showed that in adsorption/coprecipitation systems, Te(IV) was oxidized on δ-MnO2 and not oxidized on ferrihydrite. Extended X-ray Absorption Fine Structure (EXAFS) analysis showed that both Te(IV) and Te(VI) were adsorbed on the surface of δ-MnO2 and ferrihydrite via formation of inner-sphere complexes. In addition, Te(VI) can be structurally incorporated into the linkage of Fe octahedra through a coprecipitation process because of its molecular geometry that is similar to the Fe octahedron. The largest distribution coefficient obtained in the adsorption/coprecipitation experiments was for the Te(VI)/ferrihydrite coprecipitation system, and it was comparable to those calculated from the distribution between natural ferromanganese oxides and seawater. Our XAFS and micro-focused X-ray fluorescence (μ-XRF) mapping of natural ferromanganese oxides showed that Te was structurally incorporated as Te(VI) in Fe (oxyhydr)oxide phases. We conclude that the main process for the enrichment of Te in ferromanganese oxides is structural incorporation of Te(VI) into Fe (oxyhydr)oxide phases through coprecipitation. This mechanism can explain the unique degree of enrichment of Te compared with other oxyanions, which are mainly enriched via adsorption on the surface of the solid structures. In particular, the great contrast in the distributions of Te and Se is caused by their oxidized species: (i) the similar geometry of the Te(VI) molecule to Fe octahedron, and (ii) quite soluble nature of Se(VI). Coexisting Mn oxide phases may promote structural incorporation of Te(VI) by oxidation of Te(IV), although the surface oxidation itself may not work as the critical enrichment process as

  8. Novel meat-enriched foods for older consumers.

    Science.gov (United States)

    Farouk, Mustafa M; Yoo, Michelle J Y; Hamid, Nazimah S A; Staincliffe, Maryann; Davies, Briar; Knowles, Scott O

    2018-02-01

    Red meat enriched versions of bread, spaghetti, yoghurt, ice cream and chocolate were prototyped and assessed for some of their physical, chemical and microbiological properties, as well as sensory appeal. The protein content of the products were significantly increased and their colour went darker with meat enrichment (pice cream meltability and yoghurt apparent viscosity decreased with meat enrichment (pice cream and spaghetti were not affected (p>0.05) but that of non-flavoured ice cream and yoghurt went down (pindustry stretch its established business models, and encouraging further development of novel food choices for elderly and other groups of consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. GSL-enriched membrane microdomains in innate immune responses.

    Science.gov (United States)

    Nakayama, Hitoshi; Ogawa, Hideoki; Takamori, Kenji; Iwabuchi, Kazuhisa

    2013-06-01

    Many pathogens target glycosphingolipids (GSLs), which, together with cholesterol, GPI-anchored proteins, and various signaling molecules, cluster on host cell membranes to form GSL-enriched membrane microdomains (lipid rafts). These GSL-enriched membrane microdomains may therefore be involved in host-pathogen interactions. Innate immune responses are triggered by the association of pathogens with phagocytes, such as neutrophils, macrophages and dendritic cells. Phagocytes express a diverse array of pattern-recognition receptors (PRRs), which sense invading microorganisms and trigger pathogen-specific signaling. PRRs can recognize highly conserved pathogen-associated molecular patterns expressed on microorganisms. The GSL lactosylceramide (LacCer, CDw17), which binds to various microorganisms, including Candida albicans, is expressed predominantly on the plasma membranes of human mature neutrophils and forms membrane microdomains together with the Src family tyrosine kinase Lyn. These LacCer-enriched membrane microdomains can mediate superoxide generation, migration, and phagocytosis, indicating that LacCer functions as a PRR in innate immunity. Moreover, the interactions of GSL-enriched membrane microdomains with membrane proteins, such as growth factor receptors, are important in mediating the physiological properties of these proteins. Similarly, we recently found that interactions between LacCer-enriched membrane microdomains and CD11b/CD18 (Mac-1, CR3, or αMβ2-integrin) are significant for neutrophil phagocytosis of non-opsonized microorganisms. This review describes the functional role of LacCer-enriched membrane microdomains and their interactions with CD11b/CD18.

  10. Industrial plants for production of highly enriched nitrogen-15

    International Nuclear Information System (INIS)

    Krell, E.; Jonas, C.

    1977-01-01

    A discussion is presented of the present stage of development of large-scale enrichment of 15 N. The most important processes utilized to separate nitrogen isotopes, namely chemical exchange in the NO/NO 2 /HNO 3 system and low-temperature distillation of NO at -151 0 C, are compared, especially with respect to their economics and use of energy. As examples, chemical exchange plants in the GDR are discussed, and the research activities necessary to optimize the process, especially to solve aerodynamic, hydrodynamic, interface and processing problems, are reviewed. Good results were obtained by the choice of an optimum location and the design of a plant for pre-enrichment to 10 at.% 15 N and an automatically operating two-section cascade for the high enrichment of 15 N to more than 99 at.%. The chemical industry has taken over operation of the plant with the consequence that the raw materials are all available without additional transport. All by-products (nitrous gases and sulphuric acid) are returned for use elsewhere within the industry. The technology of the plant has been chosen so that the quantity of highly enriched product can be varied within a wide range. The final product is used to synthesize more than 250 different 15 N-labelled compounds which are also produced on an industrial scale. (author)

  11. Mechanism of regional enrichment of groundwater by boron: the examples of Bangladesh and Michigan, USA

    International Nuclear Information System (INIS)

    Ravenscroft, P.; McArthur, J.M.

    2004-01-01

    In Bangladesh, concentrations of boron in groundwater reach 2.1 mg L -1 and are high regionally in alluvial aquifers of Late Pleistocene/Holocene age. Concentrations exceed 0.5 mg L -1 across approximately 6700 km 2 of the deep aquifer (>150 m depth) and 3000 km 2 of the shallow aquifer ( -1 and high values are widespread in the NE of the county. These concentrations exceed the regulatory guideline values for human consumption of 0.5 mg L -1 (WHO) or 0.9 mg L -1 (USA). The boron has desorbed from mineral surfaces as freshwater flushing displaces saline waters from the aquifers. In Bangladesh, desorption is driven by decreasing ionic strength, the equilibrium re-adjustment of mineral sorption sites to the low boron concentration in freshwater, and competitive exchange with HCO 3 /CO 3 . In deep Bangladesh aquifers in Barisal District (>250 m deep), boron enrichment delineates a buried estuary marking a previous course of the Ganges and/or Brahmaputra rivers. Boron enrichment is accompanied by ion-exchange that depletes Ca and enriches Na in the flushing freshwater. The patterns of enrichment and depletion indicate the direction of water quality change, in terms of salinization or freshening, with greater sensitivity than absolute chemical parameters

  12. Analysis of Wetting and Contact Angle Hysteresis on Chemically Patterned Surfaces

    KAUST Repository

    Xu, Xianmin; Wang, Xiaoping

    2011-01-01

    Wetting and contact angle hysteresis on chemically patterned surfaces in two dimensionsare analyzed from a stationary phase-field model for immiscible two phase fluids. We first study the sharp-interface limit of the model by the method of matched asymptotic expansions. We then justify the results rigorously by the γ-convergence theory for the related variational problem and study the properties of the limiting minimizers. The results also provide a clear geometric picture of the equilibrium configuration of the interface. This enables us to explicitly calculate the total surface energy for the two phase systems on chemically patterned surfaces with simple geometries, namely the two phase flow in a channel and the drop spreading. By considering the quasi-staticmotion of the interface described by the change of volume (or volume fraction), we can follow the change-of-energy landscape which also reveals the mechanism for the stick-slip motion of the interface and contact angle hysteresis on the chemically patterned surfaces. As the interface passes throughpatterned surfaces, we observe not only stick-slip of the interface and switching of the contact angles but also the hysteresis of contact point and contact angle. Furthermore, as the size of the patternde creases to zero, the stick-slip becomes weaker but the hysteresis becomes stronger in the sense that one observes either the advancing contact angle or the receding contact angle (when the interface ismoving in the opposite direction) without the switching in between. © 2011 Society for Industrial and Applied Mathematics.

  13. Potential for supernova-induced chemical enrichment of protoglobular cluster clouds

    International Nuclear Information System (INIS)

    Dopita, M.A.; Smith, G.H.; Dominion Astrophysical Observatory, Victoria, Canada)

    1986-01-01

    This paper seeks to explain the large internal abundance variations that are seen in the globular cluster Omega Cen in terms of supernova-induced chemical enrichment that occurred when the cluster was still largely in a gaseous phase and star formation was continuing. Using a simple power-law density model of this protoglobular gas cloud, the conditions under which this can occur have been established analytically. Clouds less massive than about 100,000 solar masses are completely disrupted by supernova explosions in their adiabatic phase. In clouds of greater mass, supernova explosions occurring near the tidal radius tend to lose their hot gas and metals to the intercloud medium. For explosions occurring closer to the mass center the ejecta must be slowed below the escape velocity, and this can only occur in clouds more massive than about 3 x 10 to the 6th solar masses. If this condition is met, then the slow isothermal momentum-conserving shocks generated by the supernova explosions may eventually induce secondary star formation. For such shocks converging on the mass center, it is found that a cloud mass of at least 10 to the 7th solar masses is required for this process to be efficient. From the observed properties of Omega Cen, a primordial mass of order 10 to the 8th solar masses is estimated, which emphasizes the unusual character of this object. 39 references

  14. A numerical study of three-dimensional droplets spreading on chemically patterned surfaces

    KAUST Repository

    Zhong, Hua; Wang, Xiao-Ping; Sun, Shuyu

    2016-01-01

    We study numerically the three-dimensional droplets spreading on physically flat chemically patterned surfaces with periodic squares separated by channels. Our model consists of the Navier-Stokes-Cahn-Hilliard equations with the generalized Navier

  15. The Gaia-ESO Survey: Lithium enrichment histories of the Galactic thick and thin disc

    Science.gov (United States)

    Fu, X.; Romano, D.; Bragaglia, A.; Mucciarelli, A.; Lind, K.; Delgado Mena, E.; Sousa, S. G.; Randich, S.; Bressan, A.; Sbordone, L.; Martell, S.; Korn, A. J.; Abia, C.; Smiljanic, R.; Jofré, P.; Pancino, E.; Tautvaišienė, G.; Tang, B.; Magrini, L.; Lanzafame, A. C.; Carraro, G.; Bensby, T.; Damiani, F.; Alfaro, E. J.; Flaccomio, E.; Morbidelli, L.; Zaggia, S.; Lardo, C.; Monaco, L.; Frasca, A.; Donati, P.; Drazdauskas, A.; Chorniy, Y.; Bayo, A.; Kordopatis, G.

    2018-02-01

    Lithium abundance in most of the warm metal-poor main sequence stars shows a constarnt plateau (A(Li) 2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites, which carry information about the chemical composition of the interstellar medium (ISM) at the solar system formation time, show a lithium abundance A(Li) 3.26 dex. This pattern reflects the Li enrichment history of the ISM during the Galaxy lifetime. After the initial Li production in big bang nucleosynthesis, the sources of the enrichment include asymptotic giant branch (AGB) stars, low-mass red giants, novae, type II supernovae, and Galactic cosmic rays. The total amount of enriched Li is sensitive to the relative contribution of these sources. Thus different Li enrichment histories are expected in the Galactic thick and thin disc. We investigate the main sequence stars observed with UVES in Gaia-ESO Survey iDR4 catalogue and find a Li-anticorrelation independent of [Fe/H], Teff, and log(g). Since in stellar evolution different α enhancements at the same metallicity do not lead to a measurable Li abundance change, the anticorrelation indicates that more Li is produced during the Galactic thin disc phase than during the Galactic thick disc phase. We also find a correlation between the abundance of Li and s-process elements Ba and Y, and they both decrease above the solar metallicity, which can be explained in the framework of the adopted Galactic chemical evolution models. The full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A38

  16. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    International Nuclear Information System (INIS)

    Escalante, Maryana; Maury, Pascale; Bruinink, Christiaan M; Werf, Kees van der; Olsen, John D; Timney, John A; Huskens, Jurriaan; Hunter, C Neil; Subramaniam, Vinod; Otto, Cees

    2008-01-01

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures

  17. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Escalante, Maryana [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Maury, Pascale [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Bruinink, Christiaan M [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Werf, Kees van der [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Olsen, John D [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Timney, John A [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Huskens, Jurriaan [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hunter, C Neil [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Subramaniam, Vinod [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Otto, Cees [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands)

    2008-01-16

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures.

  18. Involvement of glycosphingolipid-enriched lipid rafts in inflammatory responses.

    Science.gov (United States)

    Iwabuchi, Kazuhisa

    2015-01-01

    Glycosphingolipids (GSLs) are membrane components consisting of hydrophobic ceramide and hydrophilic sugar moieties. GSLs cluster with cholesterol in cell membranes to form GSL-enriched lipid rafts. Biochemical analyses have demonstrated that GSL-enriched lipid rafts contain several kinds of transducer molecules, including Src family kinases. Among the GSLs, lactosylceramide (LacCer, CDw17) can bind to various microorganisms, is highly expressed on the plasma membranes of human phagocytes, and forms lipid rafts containing the Src family tyrosine kinase Lyn. LacCer-enriched lipid rafts mediate immunological and inflammatory reactions, including superoxide generation, chemotaxis, and non-opsonic phagocytosis. Therefore, LacCer-enriched membrane microdomains are thought to function as pattern recognition receptors (PRRs), which recognize pathogen-associated molecular patterns (PAMPs) expressed on microorganisms. LacCer also serves as a signal transduction molecule for functions mediated by CD11b/CD18-integrin (αM/β2-integrin, CR3, Mac-1), as well as being associated with several key cellular processes. LacCer recruits PCKα/ε and phospholipase A2 to stimulate PECAM-1 expression in human monocytes and their adhesion to endothelial cells, as well as regulating β1-integrin clustering and endocytosis on cell surfaces. This review describes the organizational and inflammation-related functions of LacCer-enriched lipid rafts.

  19. Elemental Abundances and their Implications for the Chemical Enrichment of the Boötes I Ultrafaint Galaxy

    Science.gov (United States)

    Gilmore, Gerard; Norris, John E.; Monaco, Lorenzo; Yong, David; Wyse, Rosemary F. G.; Geisler, D.

    2013-01-01

    We present a double-blind analysis of high-dispersion spectra of seven red giant members of the Boötes I ultrafaint dwarf spheroidal galaxy, complemented with re-analysis of a similar spectrum of an eighth-member star. The stars cover [Fe/H] from -3.7 to -1.9 and include a CEMP-no star with [Fe/H] = -3.33. We conclude from our chemical abundance data that Boötes I has evolved as a self-enriching star-forming system, from essentially primordial initial abundances. This allows us uniquely to investigate the place of CEMP-no stars in a chemically evolving system, in addition to limiting the timescale of star formation. The elemental abundances are formally consistent with a halo-like distribution, with enhanced mean [α/Fe] and small scatter about the mean. This is in accord with the high-mass stellar initial mass function in this low-stellar-density, low-metallicity system being indistinguishable from the present-day solar neighborhood value. There is a non-significant hint of a decline in [α/Fe] with [Fe/H]; together with the low scatter, this requires low star formation rates, allowing time for supernova ejecta to be mixed over the large spatial scales of interest. One star has very high [Ti/Fe], but we do not confirm a previously published high value of [Mg/Fe] for another star. We discuss the existence of CEMP-no stars, and the absence of any stars with lower CEMP-no enhancements at higher [Fe/H], a situation that is consistent with knowledge of CEMP-no stars in the Galactic field. We show that this observation requires there be two enrichment paths at very low metallicities: CEMP-no and "carbon-normal." Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal P82.182.B-0372, PI: G. Gilmore).

  20. Elucidation of the substitution pattern of 9,10-anthraquinones through the chemical shifts of peri-hydroxyl protons

    DEFF Research Database (Denmark)

    Schripsema, Jan; Danigno, Denise

    1996-01-01

    In 9,10-anthraquinones the chemical shift of a peri-hydroxyl proton is affected by the substituents in the other benzenoid ring. These effects are additive. They are useful for the determination of substitution patterns and have been used to revise the structures of six previously reported...... anthraquinones containing methoxyl, hydroxyl, methylenedioxy and beta-methyl substituents. Because the chemical shifts of the other protons are hardly affected by substitutions in the other ring, the characteristic chemical shifts for a wide variety of substitution patterns could be derived....

  1. Artificial muscles' enrichment text: Chemical Literacy Profile of pre-service teachers

    Science.gov (United States)

    Hernani, Ulum, Luthfi Lulul; Mudzakir, Ahmad

    2017-08-01

    This research aims to determine the profile of chemical literacy abilities of pre-service teachers based on scientific attitudes and scientific competencies in PISA 2015 through individualized learning by using an artificial muscle context based-enrichment book. This research uses descriptive method, involving 20 of the 90 randomly selected population. This research uses a multiple-choice questions instrument. The result of this research are : 1) in the attitude aspects of interest in science and technology, valuing scientific approaches to inquiry, and environmental awareness, the results obtained respectively for 90%, 80%, and 30%. 2) for scientific competence of apply appropriate scientific knowledge, identify models and representations, make appropriate predictions, and explain the potential implications of scientific knowledge for society, the results obtained respectively for 30%, 50%, 60%, and 55%. 3) For scientific competence of identify the question explored in a given scientific study and distinguish questions that could be investigated scientifically, the results obtained respectively for 30 % and 50%. 4) For scientific competence of transform data from one representation to another and draw appropriate conclusions, the results obtained respectively for 60% and 45%. Based on the results, which need to be developed in pre-service chemistry teachers are environmental awareness, apply appropriate scientific knowledge, identify the question explored in a given scientific study, and draw appropriate conclusions.

  2. Micro-patterned ZnO semiconductors for high performance thin film transistors via chemical imprinting with a PDMS stamp.

    Science.gov (United States)

    Seong, Kieun; Kim, Kyongjun; Park, Si Yun; Kim, Youn Sang

    2013-04-07

    Chemical imprinting was conducted on ZnO semiconductor films via a chemical reaction at the contact regions between a micro-patterned PDMS stamp and ZnO films. In addition, we applied the chemical imprinting on Li doped ZnO thin films for high performance TFTs fabrication. The representative micro-patterned Li doped ZnO TFTs showed a field effect mobility of 4.2 cm(2) V(-1) s(-1) after sintering at 300 °C.

  3. A numerical study of three-dimensional droplets spreading on chemically patterned surfaces

    KAUST Repository

    Zhong, Hua

    2016-09-26

    We study numerically the three-dimensional droplets spreading on physically flat chemically patterned surfaces with periodic squares separated by channels. Our model consists of the Navier-Stokes-Cahn-Hilliard equations with the generalized Navier boundary conditions. Stick-slip behavior and con-tact angle hysteresis are observed. Moreover, we also study the relationship between the effective advancing/receding angle and the two intrinsic angles of the surface patterns. By increasing the volume of droplet gradually, we find that the advancing contact line tends gradually to an equiangular octagon with the length ratio of the two adjacent sides equal to a fixed value that depends on the geometry of the pattern.

  4. Method of deuterium isotope separation and enrichment

    International Nuclear Information System (INIS)

    Benson, S.W.

    1978-01-01

    A method of separating deuterium, i.e., heavy hydrogen, from certain naturally occurring sources using tuned infrared lasers to selectively decompose specified classes of organic molecules (i.e., RX) into enriched molecular products containing deuterium atoms is described. The deuterium containing molecules are easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. The undecomposed molecules and the other reaction products which are depleted of their deuterium containing species can be catalytically treated, preferably using normal water, to restore the natural abundance of deuterium and such restored molecules can then be recycled

  5. Use of enriched {sup 74}Se and {sup 77}Se in combination with isotope pattern deconvolution to differentiate and determine endogenous and supplemented selenium in lactating rats

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Iglesias, H.; Fernandez Sanchez, M.L.; Garcia Alonso, J.I.; Sanz-Medel, A. [University of Oviedo, Department of Physical and Analytical Chemistry, Faculty of Chemistry, Oviedo (Spain)

    2007-10-15

    A quantitative methodology has been developed to differentiate between endogenous and supplemented selenium in lactating rats using two enriched selenium isotopes. Lactating rats were fed for 2 weeks with formula milk containing one enriched Se isotope, {sup 77}Se, as the metabolic tracer. The isotopic composition of selenium in serum and urine samples was then measured by collision cell ICP-MS after the addition of a solution containing another enriched isotope, {sup 74}Se, as quantitation tracer, before analysis. Isotope pattern deconvolution allowed the transformation of measured Se isotopic abundances into concentrations of natural abundance (endogenous) selenium and enriched {sup 77}Se (supplemented) present in the samples. The proposed methodology was validated using serum and urine reference materials spiked with both {sup 77}Se and {sup 74}Se. The obtained results are discussed in terms of selenium exchange and half-life in lactating rats (11-12 days) and selenium levels in serum in comparison with non-supplemented rats and control rats after maternal feeding. (orig.)

  6. Spatially Localized Chemical Patterns around an A + B → Oscillator Front.

    Science.gov (United States)

    Budroni, M A; Lemaigre, L; Escala, D M; Muñuzuri, A P; De Wit, A

    2016-02-18

    When two gels, each loaded with a different set of reactants A and B of an oscillatory reaction, are brought into contact, reaction-diffusion patterns such as waves or Turing patterns can develop in the reactive contact zone. The initial condition which separates the reactants at the beginning leads to a localization in space of the different dynamical regimes accessible to the chemical oscillator. We study here both numerically and experimentally the composite traveling structures resulting from the interaction between chemical fronts and localized waves in the case in which the reactants of such an A + B → oscillator system are those of the canonical Belousov-Zhabotinsky (BZ) oscillating reaction. A transition between different dynamics is obtained by varying the initial concentration of the organic substrate of the BZ reactants, which is one of the parameters controlling the local excitability. We show that the dynamical regime (excitable or oscillatory) characterizing the BZ oscillator in the initial contact area is the key feature which determines the spatiotemporal evolution of the system. The experimental results are in qualitative agreement with the theoretical predictions.

  7. Mineralogy and chemical composition and distribution of rare earth elements of clay-rich sediments, Central Uganda

    International Nuclear Information System (INIS)

    Nyakairu, G.W.A.

    2001-02-01

    In Uganda, Precambrian rocks are extensively weathered to sediments, which are locally altered to form considerable clay deposits. Clay-rich sediment samples were collected from the Kajjansi, Kitiko, Kitetika, and Ntawo valleys (central Uganda), all of which are currently used for traditional brick, tile, and pottery manufacture. The mineralogical and chemical characteristics, and source rocks of these clay-rich sediments is not well understood. A study using modern analytical techniques, such as XRD, to obtain the bulk mineralogical composition, and XRF and INAA analyses for whole rock major and trace element abundances was performed. The results show that the sediments are dominated by kaolinite and quartz, and minor phases include smectite, chlorite, and illite/muscovite. Whole rock chemistry shows that sediment samples rich in SiO2 have low Al, Fe, Sc and Cr contents. The high chemical index of alteration (CIA) values (87 to 96), chemical index of weathering (CIW) values around 98 and low contents of the alkali and alkali earth elements of the clay-rich sediments suggest a relatively more intense weathering source area. The clay-rich sediments as raw materials for industry were classified as silty clays from grain size analysis. The chemical and mineralogical composition results show that, taken as a whole, the clay-rich sediments possess characteristics satisfactory for brick production. The chondrite-normalized rare earth elements (REE) patterns of the clay-rich sediments show LREE enrichments and a negative Eu anomaly. The high chondrite-normalized La/Yb ratios, and Gd/Yb ratios lower than 2.0, confirm that the sediments are enriched in the LREEs. The mineralogical composition, REE contents, and elemental ratios in these sediments suggest a provenance from mainly felsic rocks, with only minor contributions from basic sources. The basic sediments were most likely derived from metasedimentary rocks, such as muscovite-biotite schists, which are characteristic

  8. Silver surface enrichment controlled by simultaneous RBS for reliable PIXE analysis of ancient coins

    International Nuclear Information System (INIS)

    Beck, L.; Alloin, E.; Berthier, C.; Reveillon, S.; Costa, V.

    2008-01-01

    Evidence of silver surface enrichment of ancient silver-copper coins has been pointed out in the past years. Surface enrichment can be fortuitous or intentional. In this paper, we have investigated the cleaning procedures usually performed after excavation or in museums. We have shown that chemicals or commercial products routinely used dissolve preferentially the copper phase and consequently contribute to the silver surface enrichment. As a result, surface analyses such as PIXE or XRF can be strongly affected by this effect. By using simultaneously RBS and PIXE, it is possible to check through the silver surface enrichment and then select the reliable measurements, characteristic of the bulk composition. Results on coins recently discovered and mechanically or chemically cleaned are presented

  9. Thermodiffusion as a means to manipulate liquid film dynamics on chemically patterned surfaces.

    Science.gov (United States)

    Kalpathy, Sreeram K; Shreyes, Amrita Ravi

    2017-06-07

    The model problem examined here is the stability of a thin liquid film consisting of two miscible components, resting on a chemically patterned solid substrate and heated from below. In addition to surface tension gradients, the temperature variations also induce gradients in the concentration of the film by virtue of thermodiffusion/Soret effects. We study the stability and dewetting behaviour due to the coupled interplay between thermal gradients, Soret effects, long-range van der Waals forces, and wettability gradient-driven flows. Linear stability analysis is first employed to predict growth rates and the critical Marangoni number for chemically homogeneous surfaces. Then, nonlinear simulations are performed to unravel the interfacial dynamics and possible locations of the film rupture on chemically patterned substrates. Results suggest that appropriate tuning of the Soret parameter and its direction, in conjunction with either heating or cooling, can help manipulate the location and time scales of the film rupture. The Soret effect can either potentially aid or oppose film instability depending on whether the thermal and solutal contributions to flow are cooperative or opposed to each other.

  10. Low-enriched fuel particle performance review

    International Nuclear Information System (INIS)

    Homan, F.; Nabielek, H.; Yang, L.

    1978-08-01

    The available data on low-enriched uranium (LEU) fuel particles were reviewed under the United States-Federal Republic of Germany Agreement. The most influential factors controlling the irradiation performance of LEU fuel particles were found to be plutonium transport, fission product transport, fuel particle mechanical performance, and fuel particle chemical performance

  11. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    Science.gov (United States)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  12. Biocompatibility of Titania Nanotube Coatings Enriched with Silver Nanograins by Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Piotr Piszczek

    2017-09-01

    Full Text Available Bioactivity investigations of titania nanotube (TNT coatings enriched with silver nanograins (TNT/Ag have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS. The metabolic activity assay (MTT was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells—PBMCs isolated from rats allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9. The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.

  13. Low-enriched fuel particle performance review

    International Nuclear Information System (INIS)

    Homan, F.; Nabielek, H.; Yang, L.

    1978-08-01

    The available data on low-enriched (LEU) fuel particles were reviewed under the United States-Federal Republic of Germany Agreement. The most influential factors controlling the irradiation performance of LEU fuel particles were found to be plutonium transport, fission product transport, fuel particle mechanical performance and fuel particle chemical performande. (orig.) [de

  14. Elucidation of time-dependent systems biology cell response patterns with time course network enrichment

    DEFF Research Database (Denmark)

    Wiwie, Christian; Rauch, Alexander; Haakonsson, Anders

    2018-01-01

    , no methods exist to integrate time series data with networks, thus preventing the identification of time-dependent systems biology responses. We close this gap with Time Course Network Enrichment (TiCoNE). It combines a new kind of human-augmented clustering with a novel approach to network enrichment...

  15. The uranium enrichment market and long-term technological options

    International Nuclear Information System (INIS)

    Schneider-Maunoury, A.

    1992-01-01

    The world enrichment market situation is clearly delineated up to the year 2000. Including the East European countries, worldwide enriched uranium requirements should reach 40 million separative work units (SWUs) a year and production capacity should reach 44 millions SWUs. Two-thirds of this capacity will be supplied by the gaseous diffusion process and one-third by the centrifuge process. The enrichment processes currently considered are: (i) the gaseous diffusion process, (ii) the centrifuge process, (iii) the chemical treatment process and (iv) the laser processes, long-term assessment of the enrichment market up to the year 2015. Two scenarios may be envisioned for the (i) Public opinion will continue to block the development of nuclear power, and requirements will level off at 40 million SWUs. (ii) Changing attitudes will favor a reasonable approach enabling a revival of nuclear power expansion around 1995. Requirements should then increase starting in 2005 and would readily attain 60 million SWUs a year by 2015. Depending on market conditions, enrichment process options will be influenced either entirely by cost considerations, without allowance for the time factor, or by need to meet demand. Demonstrations of the industrial validity of laser processes are expected by 1992 - 1995 and, if interest in nuclear power makes a comeback, decisions should be made between 1995 and 2000 to build new large-capacity enrichment plants. The gaseous diffusion process may still be used for a long time if nuclear power is judiciously employed. The centrifuge process will be fully mature by the year 2000. The uranium vapor laser processes offer the most promise and should ultimately prevail. the chemical processes, though outsiders, deserve watching. (author)

  16. Chemical pattern of brazilian apples: a chemometric approach based on the Fuji and Gala varieties

    OpenAIRE

    Vieira,Renato Giovanetti; Prestes,Rosilene Aparecida; Denardi,Frederico; Nogueira,Alessandro; Wosiacki,Gilvan

    2011-01-01

    The chemical composition of apple juices may be used to discriminate between the varieties for consumption and those for raw material. Fuji and Gala have a chemical pattern that can be used for this classification. Multivariate methods correlate independent continuous chemical descriptors with the categorical apple variety. Three main descriptors of apple juice were selected: malic acid, total reducing sugar and total phenolic compounds. A chemometric approach, employing PCA and SIMCA, was us...

  17. Comparative proteomic assessment of matrisome enrichment methodologies

    Science.gov (United States)

    Krasny, Lukas; Paul, Angela; Wai, Patty; Howard, Beatrice A.; Natrajan, Rachael C.; Huang, Paul H.

    2016-01-01

    The matrisome is a complex and heterogeneous collection of extracellular matrix (ECM) and ECM-associated proteins that play important roles in tissue development and homeostasis. While several strategies for matrisome enrichment have been developed, it is currently unknown how the performance of these different methodologies compares in the proteomic identification of matrisome components across multiple tissue types. In the present study, we perform a comparative proteomic assessment of two widely used decellularisation protocols and two extraction methods to characterise the matrisome in four murine organs (heart, mammary gland, lung and liver). We undertook a systematic evaluation of the performance of the individual methods on protein yield, matrisome enrichment capability and the ability to isolate core matrisome and matrisome-associated components. Our data find that sodium dodecyl sulphate (SDS) decellularisation leads to the highest matrisome enrichment efficiency, while the extraction protocol that comprises chemical and trypsin digestion of the ECM fraction consistently identifies the highest number of matrisomal proteins across all types of tissue examined. Matrisome enrichment had a clear benefit over non-enriched tissue for the comprehensive identification of matrisomal components in murine liver and heart. Strikingly, we find that all four matrisome enrichment methods led to significant losses in the soluble matrisome-associated proteins across all organs. Our findings highlight the multiple factors (including tissue type, matrisome class of interest and desired enrichment purity) that influence the choice of enrichment methodology, and we anticipate that these data will serve as a useful guide for the design of future proteomic studies of the matrisome. PMID:27589945

  18. Searching for self-enrichment in Cygnus OB2

    Science.gov (United States)

    Berlanas, Sara R.; Herrero, Artemio; Comerón, Fernando; Pasquali, Anna; Simón-Díaz, Sergio

    2017-11-01

    Cygnus OB2 is a rich and relatively close (d~1.4 kpc) OB association in our Galaxy. It represents an ideal testbed for our theories about self-enrichment processes produced by pollution of the interstellar medium by successive generations of massive stars. Comerón & Pasquali (2012, A&A, 543, A101) found a correlation between the age of young stellar groups in Cygnus OB2 and their Galactic longitude. If is associated with a chemical composition gradient, it could support these self-enrichment processes.

  19. South Australia, uranium enrichment

    International Nuclear Information System (INIS)

    1976-02-01

    The Report sets out the salient data relating to the establishment of a uranium processing centre at Redcliff in South Australia. It is conceived as a major development project for the Commonwealth, the South Australian Government and Australian Industry comprising the refining and enrichment of uranium produced from Australian mines. Using the data currently available in respect of markets, demand, technology and possible financial return from overseas sales, the project could be initiated immediately with hexafluoride production, followed rapidly in stages by enrichment production using the centrifuge process. A conceptual development plan is presented, involving a growth pattern that would be closely synchronised with the mining and production of yellowcake. The proposed development is presented in the form of an eight-and-half-year programme. Costs in this Report are based on 1975 values, unless otherwise stated. (Author)

  20. Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Gregory R. Mockos; William A. Smith; Frank J. Loge; David N. Thompson

    2007-04-01

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

  1. Stick-Slip Motion of Moving Contact Line on Chemically Patterned Surfaces

    KAUST Repository

    Wu, Congmin; Lei, Siulong; Qian, Tiezheng; Wang, Xiaoping

    2009-01-01

    Based on our continuum hydrodynamic model for immiscible two-phase flows at solid surfaces, the stick-slip motion has been predicted for moving contact line at chemically patterned surfaces [Wang et al., J. Fluid Mech., 605 (2008), pp. 59-78]. In this paper we show that the continuum predictions can be quantitatively verified by molecular dynamics (MD) simulations. Our MD simulations are carried out for two immiscible Lennard-Jones fluids confined by two planar solid walls in Poiseuille flow geometry. In particular, one solid surface is chemically patterned with alternating stripes. For comparison, the continuum model is numerically solved using material parameters directly measured in MD simulations. From oscillatory fluid-fluid interface to intermittent stick-slip motion of moving contact line, we have quantitative agreement between the continuum and MD results. This agreement is attributed to the accurate description down to molecular scale by the generalized Navier boundary condition in our continuum model. Numerical results are also presented for the relaxational dynamics of fluid-fluid interface, in agreement with a theoretical analysis based on the Onsager principle of minimum energy dissipation. © 2010 Global-Science Press.

  2. Physical-chemical mechanisms of pattern formation during gastrulation

    Science.gov (United States)

    Bozorgui, Behnaz; Kolomeisky, Anatoly B.; Teimouri, Hamid

    2018-03-01

    Gastrulation is a fundamental phase during the biological development of most animals when a single layer of identical embryo cells is transformed into a three-layer structure, from which the organs start to develop. Despite a remarkable progress in quantifying the gastrulation processes, molecular mechanisms of these processes remain not well understood. Here we theoretically investigate early spatial patterning in a geometrically confined colony of embryonic stem cells. Using a reaction-diffusion model, a role of Bone-Morphogenetic Protein 4 (BMP4) signaling pathway in gastrulation is specifically analyzed. Our results show that for slow diffusion rates of BMP4 molecules, a new length scale appears, which is independent of the size of the system. This length scale separates the central region of the colony with uniform low concentrations of BMP molecules from the region near the colony edge where the concentration of signaling molecules is elevated. The roles of different components of the signaling pathway are also explained. Theoretical results are consistent with recent in vitro experiments, providing microscopic explanations for some features of early embryonic spatial patterning. Physical-chemical mechanisms of these processes are discussed.

  3. Airborne uranium, its concentration and toxicity in uranium enrichment facilities

    International Nuclear Information System (INIS)

    Thomas, J.; Mauro, J.; Ryniker, J.; Fellman, R.

    1979-02-01

    The release of uranium hexafluoride and its hydrolysis products into the work environment of a plant for enriching uranium by means of gas centrifuges is discussed. The maximum permissible mass and curie concentration of airborne uranium (U) is identified as a function of the enrichment level (i.e., U-235/total U), and chemical and physical form. A discussion of the chemical and radiological toxicity of uranium as a function of enrichment and chemical form is included. The toxicity of products of UF 6 hydrolysis in the atmosphere, namely, UO 2 F 2 and HF, the particle size of toxic particulate material produced from this hydrolysis, and the toxic effects of HF and other potential fluoride compounds are also discussed. Results of an investigation of known effects of humidity and temperature on particle size of UO 2 F 2 produced by the reaction of UF 6 with water vapor in the air are reported. The relationship of the solubility of uranium compounds to their toxic effects was studied. Identification and discussion of the standards potentially applicable to airborne uranium compounds in the working environment are presented. The effectiveness of High Efficiency Particulate (HEPA) filters subjected to the corrosive environment imposed by the presence of hydrogen fluoride is discussed

  4. Designing Focused Chemical Libraries Enriched in Protein-Protein Interaction Inhibitors using Machine-Learning Methods

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O.; Sperandio, Olivier

    2010-01-01

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  5. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Directory of Open Access Journals (Sweden)

    Christelle Reynès

    2010-03-01

    Full Text Available Protein-protein interactions (PPIs may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific. Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI

  6. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O; Sperandio, Olivier

    2010-03-05

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  7. Enriching services and uranium markets from an international supplier's perspective

    International Nuclear Information System (INIS)

    Guais, J.C.; Peterson, C.H.

    1987-01-01

    In the past 10 yr, the international market for nuclear fuel cycle products and services, mainly yellowcake and separative work units (SWUs), has been characterized by shifting patterns in global demand and resource allocation. For suppliers as well as buyers, the analysis of the supply and demand pattern over the next 10 yr can be a useful exercise, especially if it highlights geopolitical realities and the influence of new technologies. This paper will attempt to answer two questions related to the marketing of natural uranium and enrichment services: (1) on a global basis (i.e., for the Western World), are uranium and enrichment capacities now on line sufficient to meet long-term demand. (2) On a regional basis (the US, Europe, and Far East), what is the short-to-medium term pattern of the supply-and-demand balance

  8. R-process enrichment from a single event in an ancient dwarf galaxy.

    Science.gov (United States)

    Ji, Alexander P; Frebel, Anna; Chiti, Anirudh; Simon, Joshua D

    2016-03-31

    Elements heavier than zinc are synthesized through the rapid (r) and slow (s) neutron-capture processes. The main site of production of the r-process elements (such as europium) has been debated for nearly 60 years. Initial studies of trends in chemical abundances in old Milky Way halo stars suggested that these elements are produced continually, in sites such as core-collapse supernovae. But evidence from the local Universe favours the idea that r-process production occurs mainly during rare events, such as neutron star mergers. The appearance of a plateau of europium abundance in some dwarf spheroidal galaxies has been suggested as evidence for rare r-process enrichment in the early Universe, but only under the assumption that no gas accretes into those dwarf galaxies; gas accretion favours continual r-process enrichment in these systems. Furthermore, the universal r-process pattern has not been cleanly identified in dwarf spheroidals. The smaller, chemically simpler, and more ancient ultrafaint dwarf galaxies assembled shortly after the first stars formed, and are ideal systems with which to study nucleosynthesis events such as the r-process. Reticulum II is one such galaxy. The abundances of non-neutron-capture elements in this galaxy (and others like it) are similar to those in other old stars. Here, we report that seven of the nine brightest stars in Reticulum II, observed with high-resolution spectroscopy, show strong enhancements in heavy neutron-capture elements, with abundances that follow the universal r-process pattern beyond barium. The enhancement seen in this 'r-process galaxy' is two to three orders of magnitude higher than that detected in any other ultrafaint dwarf galaxy. This implies that a single, rare event produced the r-process material in Reticulum II. The r-process yield and event rate are incompatible with the source being ordinary core-collapse supernovae, but consistent with other possible sources, such as neutron star mergers.

  9. Conversion and Blending Facility Highly enriched uranium to low enriched uranium as uranium hexafluoride. Revision 1

    International Nuclear Information System (INIS)

    1995-01-01

    This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF 6 and a (2) blend the pure HEU UF 6 with diluent UF 6 to produce LWR grade LEU-UF 6 . The primary emphasis of this blending be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The chemical and isotopic concentrations of the blended LEU product will be held within the specifications required for LWR fuel. The blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry

  10. Conversion and Blending Facility Highly enriched uranium to low enriched uranium as uranium hexafluoride. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-05

    This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF{sub 6} and a (2) blend the pure HEU UF{sub 6} with diluent UF{sub 6} to produce LWR grade LEU-UF{sub 6}. The primary emphasis of this blending be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The chemical and isotopic concentrations of the blended LEU product will be held within the specifications required for LWR fuel. The blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry.

  11. Method of deuterium isotope separation and enrichment

    International Nuclear Information System (INIS)

    Benson, S.W.

    1980-01-01

    A method of deuterium isotope separation and enrichment using infrared laser technology in combination with chemical processes for treating and recycling the unreacted and deuterium-depleted starting materials is described. Organic molecules of the formula RX (where R is an ethyl, isopropyl, t-butyl, or cyclopentenyl group and X is F, Cl, Br or OH) containing a normal abundance of hydrogen and deuterium are exposed to intense laser infrared radiation. An olefin containing deuterium (olefin D) will be formed, along with HX. The enriched olefin D can be stripped from the depleted stream of RX and HX, and can be burned to form enriched water or pyrolyzed to produce hydrogen gas with elevated deuterium content. The depleted RX is decomposed to olefins and RX, catalytically exchanged with normal water to restore the deuterium content to natural levels, and recombined to form RX which can be recycled. (LL)

  12. Zinc-enriched boutons in rat spinal cord

    DEFF Research Database (Denmark)

    Schrøder, H D; Danscher, G; Jo, S M

    2000-01-01

    The rat spinal cord reveals a complex pattern of zinc-enriched (ZEN) boutons. As a result of in vivo exposure to selenide ions, nanosized clusters of zinc selenide are created in places where zinc ions are present, including the zinc-containing synaptic vesicles of ZEN boutons. The clusters can...

  13. Characterization and modeling of the thermal hydraulic and chemical environment of fuel claddings of PWR reactors during boiling

    International Nuclear Information System (INIS)

    March, Ph.

    1999-01-01

    In pressurised water reactors (PWR), nucleate boiling can strongly influence the oxidation rate of the fuel cladding. To improve our understanding of the effect of the boiling phenomenon on corrosion kinetics, information about the chemical and thermal hydraulic boundary conditions at the heating rod surface is needed. Moreover, very few data are available in the range of thermal hydraulic parameters of PWR cores (15,5 MPa and 340 deg C) concerning the two-phase flow pattern close to the fuel cladding. A visualization device has been adapted on an out-of-pile loop Reggae to obtain both qualitative and quantitative data. These observations provide a direct access to the geometrical properties of the vapor inclusions, the onset of nucleate boiling and the gas velocity and trajectory. An image processing method has been validated to measure both void fraction and interfacial area concentration in a bubbly two-phase flow. Thus, the visualization device proves to be a suitable and accurate instrumentation to characterize nucleate boiling in PWR conditions. The experimental results analysis indicates that a local approach is needed for the modelling of the fuel rod chemical environment. To simulate the chemical additives enrichment, a new model is proposed where the vapor bubbles are now considered as physical obstacles for the liquid access to the rod surface. The influence of the two-phase flow pattern appears to be of major importance for the enrichment phenomenon. This study clearly demonstrates the existence of strong interactions between the two-phase flow pattern, the rod surface condition, the corrosion process and the water chemistry. (author)

  14. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  15. WaveSeq: a novel data-driven method of detecting histone modification enrichments using wavelets.

    Directory of Open Access Journals (Sweden)

    Apratim Mitra

    Full Text Available BACKGROUND: Chromatin immunoprecipitation followed by next-generation sequencing is a genome-wide analysis technique that can be used to detect various epigenetic phenomena such as, transcription factor binding sites and histone modifications. Histone modification profiles can be either punctate or diffuse which makes it difficult to distinguish regions of enrichment from background noise. With the discovery of histone marks having a wide variety of enrichment patterns, there is an urgent need for analysis methods that are robust to various data characteristics and capable of detecting a broad range of enrichment patterns. RESULTS: To address these challenges we propose WaveSeq, a novel data-driven method of detecting regions of significant enrichment in ChIP-Seq data. Our approach utilizes the wavelet transform, is free of distributional assumptions and is robust to diverse data characteristics such as low signal-to-noise ratios and broad enrichment patterns. Using publicly available datasets we showed that WaveSeq compares favorably with other published methods, exhibiting high sensitivity and precision for both punctate and diffuse enrichment regions even in the absence of a control data set. The application of our algorithm to a complex histone modification data set helped make novel functional discoveries which further underlined its utility in such an experimental setup. CONCLUSIONS: WaveSeq is a highly sensitive method capable of accurate identification of enriched regions in a broad range of data sets. WaveSeq can detect both narrow and broad peaks with a high degree of accuracy even in low signal-to-noise ratio data sets. WaveSeq is also suited for application in complex experimental scenarios, helping make biologically relevant functional discoveries.

  16. Enrichment of 15N and 18O by chemical exchange reactions between nitrogen oxides (NO, NO2) and aqueous nitric acid

    International Nuclear Information System (INIS)

    Abrudean, M.; Axente, D.; Baldea, A.

    1981-01-01

    The enrichment of 15 N and 18 O by chemical exchange in the NO, NO 2 -H 2 O, HNO 3 system is described. A laboratory experimental plant and a cascade for producing the two isotopes has been used. The production plant consists of two exchange columns for 15 N separation and two 18 O separation columns feeded with nitrogen oxides, depleted of 15 N, from the top of the first 15 N separation column. The by-products nitric acid and sulphuric acid, both depleted of 15 N and 18 O, are of commercial interest. (author)

  17. 136 Xe enrichment through cryogenic distillation

    Energy Technology Data Exchange (ETDEWEB)

    Back, Henning O.; Bottenus, Daniel R.; Clayton, Christopher K.; Stephenson, David E.; TeGrotenhuis, Ward E.

    2017-09-01

    The next generation of 136Xe neutrinoless double beta decay experiments will require on the order of 5 tons of enriched 136Xe. By estimating the relative volatilities of the xenon isotopes and using standard chemical engineering techniques we explore the feasibility of using cryogenic distillation to produce 5 tons of 80% enriched 136Xe in 5-6 years. With current state-of-the-art distillation column packing materials we can estimate the total height of a traditional cryogenic distillation column. We also, report on how Micro Channel Distillation may reduce the overall size of a distillation system for 136Xe production.

  18. Conversion and Blending Facility highly enriched uranium to low enriched uranium as oxide. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-05

    This Conversion and Blending Facility (CBF) will have two missions: (1) convert HEU materials into pure HEU oxide and (2) blend the pure HEU oxide with depleted and natural uranium oxide to produce an LWR grade LEU product. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. To the extent practical, the chemical and isotopic concentrations of blended LEU product will be held within the specifications required for LWR fuel. Such blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry. Otherwise, blended LEU will be produced as a waste suitable for storage or disposal.

  19. Patterns of development of unspecific reaction of cells and modification of chemical protection

    International Nuclear Information System (INIS)

    Veksler, A.M.; Korystov, Yu.N.; Kublik, L.N.; Ehjdus, L.Kh.

    1980-01-01

    A study was made of a correlation between radioprotective efficiency of different chemical agents (weak electrolytes) and conditions of treatment. It was demonstrated that the pattern of changes in the protection efficiency, with modification thereof, is similar to that of the development of unspecific reaction and determined by the intracellular concentration of the chemical agents, which, in turn, is function of physicochemical parameters of the substance and pH gradient between cell and medium. With similar intracellular concentration, caffeine-benzoate, thioglicolic acid and caffeine proved to be equally effective, while the protective effect of cysteamine was appreciably higher

  20. Deposition of thermal and hot-wire chemical vapor deposition copper thin films on patterned substrates.

    Science.gov (United States)

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    In this work we study the hot-wire chemical vapor deposition (HWCVD) of copper films on blanket and patterned substrates at high filament temperatures. A vertical chemical vapor deposition reactor was used in which the chemical reactions were assisted by a tungsten filament heated at 650 degrees C. Hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) vapors were used, directly injected into the reactor with the aid of a liquid injection system using N2 as carrier gas. Copper thin films grown also by thermal and hot-wire CVD. The substrates used were oxidized silicon wafers on which trenches with dimensions of the order of 500 nm were formed and subsequently covered with LPCVD W. HWCVD copper thin films grown at filament temperature of 650 degrees C showed higher growth rates compared to the thermally ones. They also exhibited higher resistivities than thermal and HWCVD films grown at lower filament temperatures. Thermally grown Cu films have very uniform deposition leading to full coverage of the patterned substrates while the HWCVD films exhibited a tendency to vertical growth, thereby creating gaps and incomplete step coverage.

  1. MARCC (Matrix-Assisted Reader Chromatin Capture): an antibody-free method to enrich and analyze combinatorial nucleosome modifications

    Science.gov (United States)

    Su, Zhangli

    2016-01-01

    Combinatorial patterns of histone modifications are key indicators of different chromatin states. Most of the current approaches rely on the usage of antibodies to analyze combinatorial histone modifications. Here we detail an antibody-free method named MARCC (Matrix-Assisted Reader Chromatin Capture) to enrich combinatorial histone modifications. The combinatorial patterns are enriched on native nucleosomes extracted from cultured mammalian cells and prepared by micrococcal nuclease digestion. Such enrichment is achieved by recombinant chromatin-interacting protein modules, or so-called reader domains, which can bind in a combinatorial modification-dependent manner. The enriched chromatin can be quantified by western blotting or mass spectrometry for the co-existence of histone modifications, while the associated DNA content can be analyzed by qPCR or next-generation sequencing. Altogether, MARCC provides a reproducible, efficient and customizable solution to enrich and analyze combinatorial histone modifications. PMID:26131849

  2. Dewetting of thin liquid films on chemically patterned substrates : front propatation along narrow lyophobic stripes and stripe arrays

    NARCIS (Netherlands)

    Brasjen, B.J.; Gu, H.; Darhuber, A.A.

    2013-01-01

    Using experiments and numerical simulations, we investigate the dewetting of thin liquid films on chemically patterned substrates. The patterns consist of long and narrow hydrophobic stripes, separated by larger hydrophilic domains. We characterize the morphology and dynamics of the dewetting front

  3. Enrichment and isolation of microbial strains degrading bioplastic ...

    African Journals Online (AJOL)

    acer

    2015-07-08

    Jul 8, 2015 ... The sea sediments and sea water samples were collected from sites highly polluted with plastic waste from one of the beaches of Mumbai, India. Polymer sample. PVA (M.W. 125000) in powdered form was purchased from S. D.. Fine Chemicals, Mumbai, India. Enrichment of PVA degrading microbial stains.

  4. Modular enrichment measurement system for in-situ enrichment assay

    International Nuclear Information System (INIS)

    Stewart, J.P.

    1976-01-01

    A modular enrichment measurement system has been designed and is in operation within General Electric's Nuclear Fuel Fabrication Facility for the in-situ enrichment assay of uranium-bearing materials in process containers. This enrichment assay system, which is based on the ''enrichment meter'' concept, is an integral part of the site's enrichment control program and is used in the in-situ assay of the enrichment of uranium dioxide (UO 2 ) powder in process containers (five gallon pails). The assay system utilizes a commercially available modular counting system and a collimnator designed for compatability with process container transport lines and ease of operator access. The system has been upgraded to include a microprocessor-based controller to perform system operation functions and to provide data acquisition and processing functions. Standards have been fabricated and qualified for the enrichment assay of several types of uranium-bearing materials, including UO 2 powders. The assay system has performed in excess of 20,000 enrichment verification measurements annually and has significantly contributed to the facility's enrichment control program

  5. Conversion and Blending Facility highly enriched uranium to low enriched uranium as uranyl nitrate hexahydrate. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-05

    This Conversion and Blending Facility (CBF) will have two missions: (1) convert HEU materials to pure HEU uranyl nitrate (UNH) and (2) blend pure HEU UNH with depleted and natural UNH to produce HEU UNH crystals. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. To the extent practical, the chemical and isotopic concentrations of blended LEU product will be held within the specifications required for LWR fuel. Such blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry. Otherwise, blended LEU Will be produced as a waste suitable for storage or disposal.

  6. Criticality of mixtures of plutonium and high enriched uranium

    International Nuclear Information System (INIS)

    Grolleau, E.; Lein, M.; Leka, G.; Maidou, B.; Klenov, P.

    2003-01-01

    This paper presents a criticality evaluation of moderated homogeneous plutonium-uranium mixtures. The fissile media studied are homogeneous mixtures of plutonium and high enriched uranium in two chemical forms: aqueous mixtures of metal and mixtures of nitrate solutions. The enrichment of uranium considered are 93.2wt.% 235 U and 100wt.% 235 U. The 240 Pu content in plutonium varies from 0wt.% 240 Pu to 12wt.% 240 Pu. The critical parameters (radii and masses of a 20 cm water reflected sphere) are calculated with the French criticality safety package CRISTAL V0. The comparison of the calculated critical parameters as a function of the moderator-to-fuel atomic ratio shows significant ranges in which high enriched uranium systems, as well as plutonium-uranium mixtures, are more reactive than plutonium systems. (author)

  7. Optimal pin enrichment distributions in nuclear reactor fuel bundles

    International Nuclear Information System (INIS)

    Lim, E.Y.

    1976-01-01

    A methodology has been developed to determine the fuel pin enrichment distribution that yields the best approximation to a prescribed power distribution in nuclear reactor fuel bundles. The problem is formulated as an optimization problem in which the optimal pin enrichments minimize the sum of squared deviations between the actual and prescribed fuel pin powers. A constant average enrichment constraint is imposed to ensure that a suitable value of reactivity is present in the bundle. When constraints are added that limit the fuel pins to a few enrichment types, one must determine not only the optimal values of the enrichment types but also the optimal distribution of the enrichment types amongst the pins. A matrix of boolean variables is used to describe the assignment of enrichment types to the pins. This nonlinear mixed integer programming problem may be rigorously solved with either exhaustive enumeration or branch and bound methods using a modification of the algorithm from the continuous problem as a suboptimization. Unfortunately these methods are extremely cumbersome and computationally overwhelming. Solutions which require only a moderate computational effort are obtained by assuming that the fuel pin enrichments in this problem are ordered as in the solution to the continuous problem. Under this assumption search schemes using either exhaustive enumeration or branch and bound become computationally attractive. An adaptation of the Hooke--Jeeves pattern search technique is shown to be especially efficient

  8. Thin polymer films on chemically patterned, corrugated substrates

    International Nuclear Information System (INIS)

    Geoghegan, Mark; Wang Chun; Rehse, Nicolaus; Magerle, Robert; Krausch, Georg

    2005-01-01

    We study the effect of a chemical pattern on the wetting and dewetting behaviour of thin polystyrene (PS) films on regularly corrugated silicon substrates. Our results reveal that the film preparation, annealing method, and confinement play a critical role in the final film structure. On evaporating gold on both sides of the facets (such that it covered the crests of the facets, and not the troughs), we observed dewetting, which proceeded to the gold, demonstrating an enthalpic effect contrary to the outcome previously observed when gold was only evaporated on one side of the facet. We also coated the substrate with octadecyltrichlorosilane (OTS); this led to a gold and OTS striped structure. PS films several nanometres thick dewet such substrates, with a preferential direction for dewetting in the direction of the stripes forming droplets of a considerably larger size than the stripes

  9. A design pattern for event-based processing of security-enriched SOAP messages

    DEFF Research Database (Denmark)

    Gruschka, Nils; Jensen, Meiko; Lo Iacono, Luigi

    2010-01-01

    For Web Services in Cloud Computing contexts, the efficient processing of XML documents is a major topic of interest. Especially for WS-Security-enriched messages, processing performance nowadays tends to become a major issue. Streaming XML processing approaches lead to valuable optimization due ...

  10. A working plan for working group 2 'enrichment' within the scope of INFCE

    International Nuclear Information System (INIS)

    1977-01-01

    A working plan for INFCE/WG.2 is presented, outlining the major questions which the group needs to answer under the headings: 1. Enrichment needs and supply, 2. Models for cross-investment, 3. Market situation, 4. Technical and economic assessment of the different enrichment technologies, and 5. Safeguards aspects. It is suggested that the group's assessment should include: 1. Future enrichment capacities, 2. Multinational or regional fuel cycle centres, 3. Possible patterns for guarantees of supply, and 4. Special needs of developing countries

  11. Foraging-Based Enrichment Promotes More Varied Behaviour in Captive Australian Fur Seals (Arctocephalus pusillus doriferus)

    Science.gov (United States)

    Hocking, David P.; Salverson, Marcia; Evans, Alistair R.

    2015-01-01

    During wild foraging, Australian fur seals (Arctocephalus pusillus doriferus) encounter many different types of prey in a wide range of scenarios, yet in captive environments they are typically provided with a narrower range of opportunities to display their full repertoire of behaviours. This study aimed to quantitatively explore the effect of foraging-based enrichment on the behaviour and activity patterns displayed by two captive Australian fur seals at Melbourne Zoo, Australia. Food was presented as a scatter in open water, in a free-floating ball device, or in a static box device, with each treatment separated by control trials with no enrichment. Both subjects spent more time interacting with the ball and static box devices than the scatter feed. The total time spent pattern swimming was reduced in the enrichment treatments compared to the controls, while the time spent performing random swimming behaviours increased. There was also a significant increase in the total number of bouts of behaviour performed in all three enrichment treatments compared to controls. Each enrichment method also promoted a different suit of foraging behaviours. Hence, rather than choosing one method, the most effective way to increase the diversity of foraging behaviours, while also increasing variation in general activity patterns, is to provide seals with a wide range of foraging scenarios where food is encountered in different ways. PMID:25946412

  12. Short communication: Using diurnal patterns of (13)C enrichment of CO2 to evaluate the effects of nitrate and docosahexaenoic acid on fiber degradation in the rumen of lactating dairy cows.

    Science.gov (United States)

    Klop, G; Bannink, A; Dieho, K; Gerrits, W J J; Dijkstra, J

    2016-09-01

    Nitrate decreases enteric CH4 production in ruminants, but may also negatively affect fiber degradation. In this experiment, 28 lactating Holstein dairy cows were grouped into 7 blocks. Within blocks, cows were randomly assigned to 1 of 4 isonitrogenous treatments in a 2×2 factorial arrangement: control (CON); NO3 [21g of nitrate/kg of dry matter (DM)]; DHA [3g of docosahexaenoic acid (DHA)/kg of DM]; or NO3+DHA (21g of nitrate/kg of DM and 3g of DHA/kg of DM). Cows were fed a total mixed ration consisting of 21% grass silage, 49% corn silage, and 30% concentrates on a DM basis. Based on the difference in natural (13)C enrichment and neutral detergent fiber and starch content between grass silage and corn silage, we investigated whether a negative effect on rumen fiber degradation could be detected by evaluating diurnal patterns of (13)C enrichment of exhaled carbon dioxide. A significant nitrate × DHA interaction was found for neutral detergent fiber digestibility, which was reduced on the NO3 treatment to an average of 55%, as compared with 61, 64, and 65% on treatments CON, DHA, and NO3+DHA, respectively. Feeding nitrate, but not DHA, resulted in a pronounced increase in (13)C enrichment of CO2 in the first 3 to 4 h after feeding only. Results support the hypothesis that effects of a feed additive on the rate of fiber degradation in the rumen can be detected by evaluating diurnal patterns of (13)C enrichment of CO2. To be able to detect this, the main ration components have to differ considerably in fiber and nonfiber carbohydrate content as well as in natural (13)C enrichment. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Application of the iron-enriched basalt waste form for immobilizing commercial transuranic waste

    International Nuclear Information System (INIS)

    Owen, D.E.

    1981-08-01

    The principal sources of commercial transuranic (TRU) waste in the United States are identified. The physical and chemical nature of the wastes from these sources are discussed. The fabrication technique and properties of iron-enriched basalt, a rock-like waste form developed for immobilizing defense TRU wastes, are discussed. The application of iron-enriched basalt to commercial TRU wastes is discussed. Review of commercial TRU wastes from mixed-oxide fuel fabrication, light water reactor fuel reprocessing, and miscellaneous medical, research, and industrial sources, indicates that iron-enriched basalt is suitable for most types of commercial TRU wastes. Noncombustible TRU wastes are dissolved in the high temperature, oxidizing iron-enriched basalt melt. Combustible TRU wastes are immobilized in iron-enriched basalt by incinerating the wastes and adding the TRU-bearing ash to the melt. Casting and controlled cooling of the melt produces a devitrified, rock-like iron-enriched basalt monolith. Recommendations are given for testing the applicability of iron-enriched basalt to commercial TRU wastes

  14. Probabilistic Neural Networks for Chemical Sensor Array Pattern Recognition: Comparison Studies, Improvements and Automated Outlier Rejection

    National Research Council Canada - National Science Library

    Shaffer, Ronald E

    1998-01-01

    For application to chemical sensor arrays, the ideal pattern recognition is accurate, fast, simple to train, robust to outliers, has low memory requirements, and has the ability to produce a measure...

  15. Recovery of Three Arctic Stream Reaches From Experimental Nutrient Enrichment.

    Science.gov (United States)

    Green, A. C.; Benstead, J. P.; Deegan, L. A.; Peterson, B. J.; Bowden, W. B.; Huryn, A. D.; Slavik, K.; Hershey, A. E.

    2005-05-01

    We examined multi-year patterns in community recovery from experimental low-concentration nutrient (N+P and P only) enrichment in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (USA). Rates of recovery varied among community components and depended on duration of enrichment (2 to 13 consecutive growing seasons). Biomass and C:P ratio of epilithic algae returned to reference levels rapidly (within 2 years), regardless of enrichment duration. Bryophyte cover, which increased greatly after long-term enrichment (>8 years), recovered to reference levels only after 7 years, when a storm scoured most remnant moss in the recovering reach. Persistence of bryophytes slowed recovery rates of insect taxa that had either been positively (e.g., Ephemerella, most chironomid taxa) or negatively (e.g., Orthocladius rivulorum) affected by this shift in dominant primary producer and its consequence for benthic habitat. Growth of Arctic grayling (adults and young-of-year), the top predator, returned to reference rates within two years. Recovery of these Arctic stream ecosystems from nutrient enrichment was consequently controlled largely by interactions between duration of enrichment and physical disturbance, mediated through physical habitat shifts caused by bryophytes.

  16. Cheese bread enriched with biofortified cowpea flour

    Directory of Open Access Journals (Sweden)

    Rodrigo Barbosa Monteiro Cavalcante

    2016-02-01

    Full Text Available ABSTRACT The development and enrichment of food are of great importance not only for the industry but also to improve the population's nutrition, where you can create new products or optimize existing ones. The consumption of fortified products in the diet is an option for the control of deficiency diseases. This study aimed to develop enriched cheese bread with whole biofortified cowpea flour and evaluate their acceptance and chemical composition. Two formulations, F1 and F2, were prepared containing 5.6 and 8% of cowpea flour as a substitute for starch, respectively. To check acceptance, three sensory tests were used (Hedonic Scale, Purchase Intent, and Paired Comparison, F1 being sensory viable according to assessors, being chemically analyzed. Minerals were determined by atomic emission spectrometry with inductively coupled plasma source. The moisture was determined by drying at 105 °C, ash by calcination in muffle at 550 °C, proteins by the macro-Kjeldahl method, and lipids by hot extraction in a Soxhlet extractor. Carbohydrates were obtained by difference and the calories were calculated. The addition of cowpea increased the amounts of copper, iron, phosphorus, magnesium, manganese, and zinc, as well as protein and carbohydrate values. On the other hand, there was a reduction of the moisture concerning lipids and the total caloric value compared to the standard formulation. It was concluded , therefore, that the cowpea, a regional raw material in market expansion is presented as an option for the enrichment of baked foods that do not contain gluten, such as cheese bread.

  17. Comparing bee species responses to chemical mixtures: Common response patterns?

    Directory of Open Access Journals (Sweden)

    Alex Robinson

    Full Text Available Pollinators in agricultural landscapes can be exposed to mixtures of pesticides and environmental pollutants. Existing mixture toxicity modelling approaches, such as the models of concentration addition and independent action and the mechanistic DEBtox framework have been previously shown as valuable tools for understanding and ultimately predicting joint toxicity. Here we apply these mixture models to investigate the potential to interpret the effects of semi-chronic binary mixture exposure for three bee species: Apis mellifera, Bombus terrestris and Osmia bicornis within potentiation and mixture toxicity experiments. In the potentiation studies, the effect of the insecticide dimethoate with added propiconazole fungicide and neonicotinoid insecticide clothianidin with added tau-fluvalinate pyrethroid acaricide showed no difference in toxicity compared to the single chemical alone. Clothianidin toxicity showed a small scale, but temporally conserved increase in exposure conducted in the presence of propiconazole, particularly for B. terrestris and O. bicornis, the latter showing a near three-fold increase in clothianidin toxicity in the presence of propiconazole. In the mixture toxicity studies, the dominant response patterns were of additivity, however, binary mixtures of clothianidin and dimethoate in A. mellifera, B. terrestris and male O. bicornis there was evidence of a predominant antagonistic interaction. Given the ubiquitous nature of exposures to multiple chemicals, there is an urgent need to consider mixture effects in pollinator risk assessments. Our analyses suggest that current models, particularly those that utilise time-series data, such as DEBtox, can be used to identify additivity as the dominant response pattern and also those examples of interactions, even when small-scale, that may need to be taken into account during risk assessment.

  18. Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.

    Science.gov (United States)

    Kalpathy, Sreeram K; Francis, Lorraine F; Kumar, Satish

    2013-10-15

    A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Report of Sectional Committee on Industrialization of Uranium Enrichment

    International Nuclear Information System (INIS)

    1981-01-01

    In order to accelerate the development and utilization of atomic energy which is the core of the substitute energies for petroleum, it is indispensable requirement to establish independent fuel cycle as the base. In particular, the domestic production of enriched uranium is necessary to eliminate the obstacles to secure the energy supply in Japan. The construction and operation of the pilot plant for uranium enrichment by centrifugal separation method have progressed smoothly, and the technical base for the domestic production of enriched uranium is being consolidated. For the time being, the service of uranium enrichment is given by USA and France, but it is expected that the short supply will arise around 1990. The start of operation of the uranium enrichment plant in Japan is scheduled around 1990, and the scale of the plant will be expanded stepwise thereafter. The scale of production is assumed as 3000 t SWU/year in 2000. Prior to this commercial plant, the prototype plant of up to 250 t SWU/year capacity will be operated in 1986, starting the production of centrifugal separators in 1983. The production line for centrifugal separators will have the capacity of up to 125 t SWU/year. The organization for operating these plants, the home production of natural uranium conversion, the uranium enrichment by chemical method and others are described. (Kako, I.)

  20. Technical status study of heavy water enrichment

    International Nuclear Information System (INIS)

    Sukarsono; Imam Dahroni; Didik Herhady

    2007-01-01

    Technical status study of heavy water enrichment in Indonesia and also in the world has been done. Heavy water enrichment processes have been investigated were water distillation, hydrogen distillation, laser enrichment, electrolysis and isotop exchange. For the isotop exchange, the chemical pair can be used were water-hydrogen sulphite, ammonium-hydrogen, aminomethane-hydrogen, and water-hydrogen. For the isotope exchange, there was carried out by mono thermal or bi thermal. The highest producer of heavy water is Canada, and the other producer is USA, Norwegian and India. The processes be used in the world are isotope exchange Girdler Sulphide (GS), distillation and electrolysis. Research of heavy water carried out in Batan Yogyakarta, has a purpose to know the characteristic of heavy water purification. Several apparatus which has erected were 3 distillation column: Pyrex glass of 2 m tall, stainless steel column of 3 m tall and steel of 6 m tall. Electrolysis apparatus is 50 cell electrolysis and an isotope exchange unit which has catalyst: Ni- Cr 2 O 3 and Pt-Carbon. These apparatus were not ready to operate. (author)

  1. Vertical profiles and enrichment pattern of natural radionuclides in monazite areas of coastal Kerala

    International Nuclear Information System (INIS)

    Shetty, P.K.; Narayana, Y.; Siddappa, K.

    2006-01-01

    Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The sand samples collected at different distances from sea waterline and at different depths, were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of sand to study the enrichment pattern. The highest activity was found confined in 125-63 μm particle size fraction in sand. The minimum 232 Th activity was 9.4 Bq kg -1 , found in Kollam at a depth of 10-20 cm, 40 m away from waterline in 500-250 μm particle size fraction and maximum activity of 136,811.2 Bq kg -1 was observed in Chavara in grains of size 125-63 μm at a depth of 0-10 cm for a sample collected 20 m away from waterline. The lowest 226 Ra activity observed was 29.6 Bq kg -1 at Kollam beach for a sample 40 m away from waterline in grains of size 1000-500 μm and at a depth of 20-30 cm and the highest activity observed was 10,309 Bq kg -1 in grains of size 125-63 μm for a sample collected at a distance 20 m away from waterline and at a depth of 0-10 cm. The activity of 4 K was below detectable level in most of the samples collected from the high background monazite area. The 232 Th, 226 Ra activities decrease with depth for the samples collected 20 m away from the waterline and increase with depth for the samples collected 40 m away from the waterline at Chavara and Kollam beaches. No definite correlation was found between variation of the concentrations of 232 Th and 226 Ra with depth at Karunagapalli and Neendakara beach sands. There exists a strong correlation between 226 Ra and 232 Th activities in the region. The results of these investigations are presented and discussed in this paper

  2. Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

    Science.gov (United States)

    Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

    2015-09-01

    Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions.

  3. Effect of increasing helium content and disk dwarfs evolution on the chemical enrichment of the galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Caimmi, R [Padua Univ. (Italy). Ist. di Astronomia

    1979-07-01

    The author deals with two main effects: First the empirical metal abundance distribution in Main Sequence disk dwarfs of the solar neighbourhood, and second, the theoretical possibility of (i) an increased helium content as the Galaxy evolves, and (ii) the presence of evolutionary effects in disk dwarfs (i.e., the age of some or all stars considered up to the subgiant phase is not necessarily longer than the age of the galactic disk). Account is taken of a linear increase of helium content with metal content, and some constraints are imposed relative to initial, solar and present-day observed values of Y and Z, and to observed relative helium to heavy element enrichment, ..delta..Y/..delta..Z. In this way, little influence is found on the empirical metal abundance distribution in the range 0<=..delta..Y/..delta..Z<=3, while larger values of ..delta..Y/..delta..Zwould lead to a more significant influence. 'Evolved' and 'unevolved' theoretical metal abundance distributions are derived by accounting for a two-phase model of chemical evolution of galaxies and for a linear mass dependence of star lifetimes in the spectral range G2V-G8V and are compared with the empirical distribution. All are in satisfactory agreement due to systematic shift data by different observations; several values of collapse time Tsub(c) and age of the Galaxy T are also considered. Finally, models of chemical evolution invoking homogeneous collapse without infall and inhomogeneous collapse with infall, are briefly discussed relative to the empirical metal abundance distribution in Main Sequence disk dwarfs of the solar neighbourhood.

  4. Constellation Map: Downstream visualization and interpretation of gene set enrichment results [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Yan Tan

    2015-06-01

    Full Text Available Summary: Gene set enrichment analysis (GSEA approaches are widely used to identify coordinately regulated genes associated with phenotypes of interest. Here, we present Constellation Map, a tool to visualize and interpret the results when enrichment analyses yield a long list of significantly enriched gene sets. Constellation Map identifies commonalities that explain the enrichment of multiple top-scoring gene sets and maps the relationships between them. Constellation Map can help investigators take full advantage of GSEA and facilitates the biological interpretation of enrichment results. Availability: Constellation Map is freely available as a GenePattern module at http://www.genepattern.org.

  5. Centrifugal partition chromatography enables selective enrichment of trimeric and tetrameric proanthocyanidins for biomaterial development.

    Science.gov (United States)

    Phansalkar, Rasika S; Nam, Joo-Won; Chen, Shao-Nong; McAlpine, James B; Leme, Ariene A; Aydin, Berdan; Bedran-Russo, Ana-Karina; Pauli, Guido F

    2018-02-02

    Proanthocyanidins (PACs) find wide applications for human use including food, cosmetics, dietary supplements, and pharmaceuticals. The chemical complexity associated with PACs has triggered the development of various chromatographic techniques, with countercurrent separation (CCS) gaining in popularity. This study applied the recently developed DESIGNER (Depletion and Enrichment of Select Ingredients Generating Normalized Extract Resources) approach for the selective enrichment of trimeric and tetrameric PACs using centrifugal partition chromatography (CPC). This CPC method aims at developing PAC based biomaterials, particularly for their application in restoring and repairing dental hard tissue. A general separation scheme beginning with the depletion of polymeric PACs, followed by the removal of monomeric flavan-3-ols and a final enrichment step produced PAC trimer and tetramer enriched fractions. A successful application of this separation scheme is demonstrated for four polyphenol rich plant sources: grape seeds, pine bark, cinnamon bark, and cocoa seeds. Minor modifications to the generic DESIGNER CCS method were sufficient to accommodate the varying chemical complexities of the individual source materials. The step-wise enrichment of PAC trimers and tetramers was monitored using normal phase TLC and Diol-HPLC-UV analyses. CPC proved to be a reliable tool for the selective enrichment of medium size oligomeric PACs (OPACs). This method plays a key role in the development of dental biomaterials considering its reliability and reproducibility, as well as its scale-up capabilities for possible larger-scale manufacturing. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. BiNChE: a web tool and library for chemical enrichment analysis based on the ChEBI ontology.

    Science.gov (United States)

    Moreno, Pablo; Beisken, Stephan; Harsha, Bhavana; Muthukrishnan, Venkatesh; Tudose, Ilinca; Dekker, Adriano; Dornfeldt, Stefanie; Taruttis, Franziska; Grosse, Ivo; Hastings, Janna; Neumann, Steffen; Steinbeck, Christoph

    2015-02-21

    Ontology-based enrichment analysis aids in the interpretation and understanding of large-scale biological data. Ontologies are hierarchies of biologically relevant groupings. Using ontology annotations, which link ontology classes to biological entities, enrichment analysis methods assess whether there is a significant over or under representation of entities for ontology classes. While many tools exist that run enrichment analysis for protein sets annotated with the Gene Ontology, there are only a few that can be used for small molecules enrichment analysis. We describe BiNChE, an enrichment analysis tool for small molecules based on the ChEBI Ontology. BiNChE displays an interactive graph that can be exported as a high-resolution image or in network formats. The tool provides plain, weighted and fragment analysis based on either the ChEBI Role Ontology or the ChEBI Structural Ontology. BiNChE aids in the exploration of large sets of small molecules produced within Metabolomics or other Systems Biology research contexts. The open-source tool provides easy and highly interactive web access to enrichment analysis with the ChEBI ontology tool and is additionally available as a standalone library.

  7. Chemical Applications for Enhanced World Security

    Energy Technology Data Exchange (ETDEWEB)

    Leibman, Christopher Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-19

    The purpose of this project is to reduce complexity of chemical analysis by combining chemical and physical processing steps into on package; develop instrumentation that cost less and is easy to use in a field laboratory by non-experts; and develop this "chemical application" so uranium enrichment can be measured onsite, eliminating the need for radioactive sample transport.

  8. Uranium enrichment

    International Nuclear Information System (INIS)

    1990-01-01

    This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

  9. Behavioral responses of three lemur species to different food enrichment devices.

    Science.gov (United States)

    Shapiro, Morgan E; Shapiro, Hannah G; Ehmke, Erin E

    2018-05-01

    Environmental enrichment is a tool used to promote the welfare and well-being of captive animals by encouraging the display of species-specific behaviors and reducing the stress or boredom induced by captive environments. Lemurs are highly endangered, yet few studies have analyzed the behavioral impacts of enrichment on captive populations. We studied the impacts of two novel enrichment devices on three lemur species (ring-tailed lemurs [Lemur catta], red-ruffed lemurs [Varecia rubra], and Coquerel's sifaka [Propithecus coquereli]) to determine both the overall and species-specific impacts of enrichment on lemur behavior. We recorded lemur behavior using the continuous sampling method to obtain behavior duration and analyzed our results using ANOVA Repeated Measures. Results showed enrichment effectiveness differed for each species and that different enrichment devices had varying impacts on lemur behavior across all species. We attributed the differences in species-specific responses to the unique locomotor patterns and methods of diet acquisition of each species, and the variances in behavioral responses across all species to the characteristics of each device. Our study highlights the importance of species-specific enrichment and encourages further research in this field in order to maximize the positive effects of enrichment, which in turn has the potential to affect the overall well-being of captive populations. © 2018 Wiley Periodicals, Inc.

  10. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: a model study.

    Science.gov (United States)

    Brandt-Pollmann, U; Lebiedz, D; Diehl, M; Sager, S; Schlöder, J

    2005-09-01

    Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.

  11. Patterns and trends in injuries due to chemicals based on OSHA occupational injury and illness statistics

    Energy Technology Data Exchange (ETDEWEB)

    Mannan, M. Sam [Mary Kay O' Connor Process Safety Center, Chemical Engineering Department, Texas A and M University System, College Station, TX 77843-3122 (United States)], E-mail: mannan@tamu.edu; O' Connor, T. Michael [Mary Kay O' Connor Process Safety Center, Chemical Engineering Department, Texas A and M University System, College Station, TX 77843-3122 (United States); Keren, Nir [Department of Agriculture and Biosystems Engineering, 102 Industrial Education Building II, Iowa State University, Ames, IA 50011-3130 (United States)

    2009-04-15

    The Occupational Safety and Health Administration (OSHA) and the Bureau of Labor Statistics (BLS) provide the Survey of Occupational Illness and Injury (SOII) statistics from 1992 to 2006, which is often used to measure the rate of injuries and illness in industry. The present system of gathering and classifying this data was implemented in 1992 with minor changes in 2002. It is hoped that using these statistics to measure safety progress and determine patterns of injury will guide further improvements in chemical safety. Recognizing such factors as what chemicals most frequently cause injury can help to focus safety efforts regarding that chemical. Factors such as what part of the body is most commonly affected by particular chemicals can lead to improved personnel protection practices. This paper provides a detailed analysis of injuries due to chemicals using OSHA's SOII data, which offers valuable insight into measures that should be taken to reduce injuries due to chemicals.

  12. Patterns and trends in injuries due to chemicals based on OSHA occupational injury and illness statistics

    International Nuclear Information System (INIS)

    Mannan, M. Sam; O'Connor, T. Michael; Keren, Nir

    2009-01-01

    The Occupational Safety and Health Administration (OSHA) and the Bureau of Labor Statistics (BLS) provide the Survey of Occupational Illness and Injury (SOII) statistics from 1992 to 2006, which is often used to measure the rate of injuries and illness in industry. The present system of gathering and classifying this data was implemented in 1992 with minor changes in 2002. It is hoped that using these statistics to measure safety progress and determine patterns of injury will guide further improvements in chemical safety. Recognizing such factors as what chemicals most frequently cause injury can help to focus safety efforts regarding that chemical. Factors such as what part of the body is most commonly affected by particular chemicals can lead to improved personnel protection practices. This paper provides a detailed analysis of injuries due to chemicals using OSHA's SOII data, which offers valuable insight into measures that should be taken to reduce injuries due to chemicals

  13. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    Directory of Open Access Journals (Sweden)

    Nicholas A Paul

    Full Text Available All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells. To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  14. Gas-phase UF6 enrichment monitor for enrichment plant safeguards

    International Nuclear Information System (INIS)

    Strittmatter, R.B.; Tape, J.W.

    1980-03-01

    An in-line enrichment monitor is being developed to provide real-time enrichment data for the gas-phase UF 6 feed stream of an enrichment plant. The nondestructive gamma-ray assay method can be used to determine the enrichment of natural UF 6 with a relative precision of better than 1% for a wide range of pressures

  15. Nano-patterning of perpendicular magnetic recording media by low-energy implantation of chemically reactive ions

    International Nuclear Information System (INIS)

    Martin-Gonzalez, M.S.; Briones, F.; Garcia-Martin, J.M.; Montserrat, J.; Vila, L.; Faini, G.; Testa, A.M.; Fiorani, D.; Rohrmann, H.

    2010-01-01

    Magnetic nano-patterning of perpendicular hard disk media with perpendicular anisotropy, but preserving disk surface planarity, is presented here. Reactive ion implantation is used to locally modify the chemical composition (hence the magnetization and magnetic anisotropy) of the Co/Pd multilayer in irradiated areas. The procedure involves low energy, chemically reactive ion irradiation through a resist mask. Among N, P and As ions, P are shown to be most adequate to obtain optimum bit density and topography flatness for industrial Co/Pd multilayer media. The effect of this ion contributes to isolate perpendicular bits by destroying both anisotropy and magnetic exchange in the irradiated areas. Low ion fluences are effective due to the stabilization of atomic displacement levels by the chemical effect of covalent impurities.

  16. Development and industrial application of gas centrifuges to uranium enrichment in the USSR

    International Nuclear Information System (INIS)

    Abbakumov, E.I.; Bazhenov, V.A.; Verbin, Yu.V.

    1989-01-01

    Review of state and studies in the field of gaseous diffusion technology and centrifugal method of uranium enrichment in the USSR is given. Domestic industrial gas centrifuges, forming to-day the main part of separation capacities in the USSR, are noted for low specific energy consumption and high reliability. Centrifugal technology in the USSR is applied both to uranium enrichment (including one for export) and to separation of isotopes of other chemical elements

  17. EU REPRO: The Production of fish feed enriched with poly-unsaturated fatty acid

    CSIR Research Space (South Africa)

    Erasmus, C

    2007-01-01

    Full Text Available .2 The Production of Fish Feed enriched with poly-unsaturated fatty acids Corinda Erasmus Annali Jacobs Gerda Lombard Petrus van Zyl Judy Reddy Ntombikayise Nkomo Elizabeth Timme Partner 11 Slide 2 © CSIR 2006 www... www.csir.co.za FLOW DIAGRAM OF THE PRODUCTION OF EPA- ENRICHED FISH FEED BSG (SPENT GRAIN) Eicosapentaenoic Acid (EPA) Protein-rich BSG FISH FEED PELLETS MODIFICATION OF BSG (ENZYME/CHEMICAL/MECHANICAL) FERMENTATION (RECOVERY OF EPA...

  18. R and D on laser uranium enrichment

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    An AEC Advisory Committee on Uranium Enrichment has completed investigations into the actual condition of laser isotope separation. The working group set up for the purpose has issued a report on the series of investigations made on its development and measures for promoting it. The report says that the development of the process in Japan is at a fundamental stage. Noting that further efforts are needed before its future can be predicted, the report proposes a cource of research and development for the immediate future. For the atomic vapor laser isotope separation (AVLIS), government organizations are engaged in data base buildup and conducting basis engineering tests, and Japan Atomic Energy Research Institute will consider the re-enrichment of uranium recovered from reprocessing. Non-governmental unions of researchers will promote the combination of copper-vapor laser and dye laser. For the molecular laser isotope separation (MLIS), the Institute of Physical and Chemical Research will take up studies with the cooperation of the Power Reactor and Nuclear Fuel Development Corporation. In chapters covering the philosophy of laser uranium enrichment technology development, the report deals with its significance, actual conditions and tasks, and goals and measures for its promotion. (Nogami, K.)

  19. Prediction of Effective Drug Combinations by Chemical Interaction, Protein Interaction and Target Enrichment of KEGG Pathways

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2013-01-01

    Full Text Available Drug combinatorial therapy could be more effective in treating some complex diseases than single agents due to better efficacy and reduced side effects. Although some drug combinations are being used, their underlying molecular mechanisms are still poorly understood. Therefore, it is of great interest to deduce a novel drug combination by their molecular mechanisms in a robust and rigorous way. This paper attempts to predict effective drug combinations by a combined consideration of: (1 chemical interaction between drugs, (2 protein interactions between drugs’ targets, and (3 target enrichment of KEGG pathways. A benchmark dataset was constructed, consisting of 121 confirmed effective combinations and 605 random combinations. Each drug combination was represented by 465 features derived from the aforementioned three properties. Some feature selection techniques, including Minimum Redundancy Maximum Relevance and Incremental Feature Selection, were adopted to extract the key features. Random forest model was built with its performance evaluated by 5-fold cross-validation. As a result, 55 key features providing the best prediction result were selected. These important features may help to gain insights into the mechanisms of drug combinations, and the proposed prediction model could become a useful tool for screening possible drug combinations.

  20. Method for separation and enrichment of isotopes

    International Nuclear Information System (INIS)

    Kakihana, H.; Miyamatsu, T.

    1977-01-01

    Boron or uranium isotopes can be chemically separated and enriched with high speed and with high separating efficiency by using weakly basic anion exchange fibers having a diameter of not more than 100 μ, an aspect ratio of at least 5 and an exchange capacity of at least 2 meq/g-dry fiber, which are packed in a column at a specific volume of 2.0 to 20.0 ml/g-dry fiber

  1. Uranium enrichment

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.

    1988-06-01

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  2. Cellular attachment and spatial control of cells using micro-patterned ultra-violet/ozone treatment in serum enriched media.

    Science.gov (United States)

    Mitchell, S A; Poulsson, A H C; Davidson, M R; Emmison, N; Shard, A G; Bradley, R H

    2004-08-01

    Ultra-violet Ozone (UVO) modified polystyrene (PS) surfaces were analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle (CA), optical microscopy (OM) and cell culture experiments. UV/Ozone treatment up to 900 s was used to increase the surface oxygen concentration of PS surfaces from 0% to approximately 35% (unwashed) and 0% to approximately 27% (washed). The observed differences in oxygen concentration, between washed and unwashed surfaces, have been previously attributed to the removal of low molecular weight debris produced in this treatment process. Surface roughness (Rq) is known to affect cellular attachment and proliferation. AFM studies of the UV/Ozone treated PS surfaces show the surface roughness is an order of magnitude less than that expected to cause an effect. UV/Ozone treatment of PS showed a marked change in CA which decreased to approximately 60 degrees after 900 s treatment. The increased attachment and proliferation of Chinese hamster ovarian (CHO) and mouse embryo 3T3-L1 (3T3) cells on the treated surfaces compared to untreated PS were found to correlate strongly with the increase in surface oxygen concentration. Surface chemical oxidation patterns on the PS were produced using a simple masking technique and a short UV/Ozone treatment time, typically 20-45 s. The chemical patterns on PS were visualized by water condensation and the spatially selective attachment of CHO and 3T3-L1 cells cultured with 10% (v/v) serum. This paper describes an easily reproducible, one step technique to produce a well-defined, chemically heterogeneous surface with a cellular resolution using UV/Ozone modification. By using a variety of cell types, that require different media conditions, we have been able to expand the potential applications of this procedure.

  3. Chemical modifications of Au/SiO2 template substrates for patterned biofunctional surfaces.

    Science.gov (United States)

    Briand, Elisabeth; Humblot, Vincent; Landoulsi, Jessem; Petronis, Sarunas; Pradier, Claire-Marie; Kasemo, Bengt; Svedhem, Sofia

    2011-01-18

    The aim of this work was to create patterned surfaces for localized and specific biochemical recognition. For this purpose, we have developed a protocol for orthogonal and material-selective surface modifications of microfabricated patterned surfaces composed of SiO(2) areas (100 μm diameter) surrounded by Au. The SiO(2) spots were chemically modified by a sequence of reactions (silanization using an amine-terminated silane (APTES), followed by amine coupling of a biotin analogue and biospecific recognition) to achieve efficient immobilization of streptavidin in a functional form. The surrounding Au was rendered inert to protein adsorption by modification by HS(CH(2))(10)CONH(CH(2))(2)(OCH(2)CH(2))(7)OH (thiol-OEG). The surface modification protocol was developed by testing separately homogeneous SiO(2) and Au surfaces, to obtain the two following results: (i) SiO(2) surfaces which allowed the grafting of streptavidin, and subsequent immobilization of biotinylated antibodies, and (ii) Au surfaces showing almost no affinity for the same streptavidin and antibody solutions. The surface interactions were monitored by quartz crystal microbalance with dissipation monitoring (QCM-D), and chemical analyses were performed by polarization modulation-reflexion absorption infrared spectroscopy (PM-RAIRS) and X-ray photoelectron spectroscopy (XPS) to assess the validity of the initial orthogonal assembly of APTES and thiol-OEG. Eventually, microscopy imaging of the modified Au/SiO(2) patterned substrates validated the specific binding of streptavidin on the SiO(2)/APTES areas, as well as the subsequent binding of biotinylated anti-rIgG and further detection of fluorescent rIgG on the functionalized SiO(2) areas. These results demonstrate a successful protocol for the preparation of patterned biofunctional surfaces, based on microfabricated Au/SiO(2) templates and supported by careful surface analysis. The strong immobilization of the biomolecules resulting from the described

  4. Arsenic in the environment: enrichments in the Slovenian soils

    Directory of Open Access Journals (Sweden)

    Mateja Gosar

    2005-12-01

    Full Text Available Arsenic, a toxic element with metalloid properties, is found in detectable concentrations in environmental samples. In nature it is enriched in metal (sulphide ore deposits, mainly as arsenides of Cu, Ni and Fe. Arsenic compounds are used mainly in agricultureand forestry as pesticides and herbicides. The ecosystem can be contaminated with arsenic via both natural and anthropogenic sources. Uses of arsenic contaminated water present so far the greatest health hazard. Occurrences of mining related arsenic problems havealso been recorded in many parts of the world.The impact of mining and metallurgic industry with regard to arsenic contents in soils in some potentially contaminated areas in Slovenia is discussed. Enriched contents of arsenic were found in Mežica. Arsenic correlates very well with lead, zinc and other heavymetals which are enriched as a result of long lasting lead production in the area. Also in Celje and Jesenice arsenic has the same distribution pattern as other anthropogenically introduced pollutants. In Idrija there are some slightly arsenic enriched areas, but there is no correlation with mercury, so the origin of arsenic in not clear yet.

  5. The effects of auditory enrichment on gorillas.

    Science.gov (United States)

    Robbins, Lindsey; Margulis, Susan W

    2014-01-01

    Several studies have demonstrated that auditory enrichment can reduce stereotypic behaviors in captive animals. The purpose of this study was to determine the relative effectiveness of three different types of auditory enrichment-naturalistic sounds, classical music, and rock music-in reducing stereotypic behavior displayed by Western lowland gorillas (Gorilla gorilla gorilla). Three gorillas (one adult male, two adult females) were observed at the Buffalo Zoo for a total of 24 hr per music trial. A control observation period, during which no sounds were presented, was also included. Each music trial consisted of a total of three weeks with a 1-week control period in between each music type. The results reveal a decrease in stereotypic behaviors from the control period to naturalistic sounds. The naturalistic sounds also affected patterns of several other behaviors including locomotion. In contrast, stereotypy increased in the presence of classical and rock music. These results suggest that auditory enrichment, which is not commonly used in zoos in a systematic way, can be easily utilized by keepers to help decrease stereotypic behavior, but the nature of the stimulus, as well as the differential responses of individual animals, need to be considered. © 2014 Wiley Periodicals, Inc.

  6. Transgenerational effects of environmental enrichment on repetitive motor behavior development.

    Science.gov (United States)

    Bechard, Allison R; Lewis, Mark H

    2016-07-01

    The favorable consequences of environmental enrichment (EE) on brain and behavior development are well documented. Much less is known, however, about transgenerational benefits of EE on non-enriched offspring. We explored whether transgenerational effects of EE might extend to the development of repetitive motor behaviors in deer mice. Repetitive motor behaviors are invariant patterns of movement that, across species, can be reduced by EE. We found that EE not only attenuated the development of repetitive behavior in dams, but also in their non-enriched offspring. Moreover, maternal behavior did not seem to mediate the transgenerational effect we found, although repetitive behavior was affected by reproductive experience. These data support a beneficial transgenerational effect of EE on repetitive behavior development and suggest a novel benefit of reproductive experience. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Chemical pattern of brazilian apples: a chemometric approach based on the Fuji and Gala varieties

    Directory of Open Access Journals (Sweden)

    Renato Giovanetti Vieira

    2011-06-01

    Full Text Available The chemical composition of apple juices may be used to discriminate between the varieties for consumption and those for raw material. Fuji and Gala have a chemical pattern that can be used for this classification. Multivariate methods correlate independent continuous chemical descriptors with the categorical apple variety. Three main descriptors of apple juice were selected: malic acid, total reducing sugar and total phenolic compounds. A chemometric approach, employing PCA and SIMCA, was used to classify apple juice samples. PCA was performed with 24 juices from Fuji and Gala, and SIMCA, with 15 juices. The exploratory and predictive models recognized 88% and 64%, respectively, as belonging to a mixed domain. The apple juice from commercial fruits shows a pattern related to cv. Fuji and Gala with boundaries from 0.18 to 0.389 g.100 mL-1 (malic acid, from 8.65 to 15.18 g.100 mL-1 (total reducing sugar and from 100 to 400 mg.L-1 (total phenolic compounds, but such boundaries were slightly shorter in the remaining set of commercial apple juices, specifically from 0.16 to 0.36 g.100 mL-1, from 9.25 to 15.5 g.100 mL-1 and from 180 to 606 mg.L-1 for acidity, reducing sugar and phenolic compounds, respectively, representing the acid, sweet and bitter tastes.

  8. Environmental Enrichment Effect on Fecal Glucocorticoid Metabolites and Captive Maned Wolf (Chrysocyon brachyurus) Behavior.

    Science.gov (United States)

    Coelho, Carlyle Mendes; de Azevedo, Cristiano Schetini; Guimarães, Marcelo Alcino de Barros Vaz; Young, Robert John

    2016-01-01

    Environmental enrichment is a technique that may reduce the stress of nonhuman animals in captivity. Stress may interfere with normal behavioral expression and affect cognitive decision making. Noninvasive hormonal studies can provide important information about the stress statuses of animals. This study evaluated the effectiveness of different environmental enrichment treatments in the diminution of fecal glucocorticoid metabolites (stress indicators) of three captive maned wolves (Chrysocyon brachyurus). Correlations of the fecal glucocorticoid metabolite levels with expressed behaviors were also determined. Results showed that environmental enrichment reduced fecal glucocorticoid metabolite levels. Furthermore, interspecific and foraging enrichment items were most effective in reducing stress in two of the three wolves. No definite pattern was found between behavioral and physiological responses to stress. In conclusion, these behavioral and physiological data showed that maned wolves responded positively from an animal well being perspective to the enrichment items presented.

  9. Advanced enrichment techniques

    International Nuclear Information System (INIS)

    Johnson, A.

    1988-01-01

    BNFL is in a unique position in that it has commercial experience of diffusion enrichment, and of centrifuge enrichment through its associate company Urenco. In addition BNFL is developing laser enrichment techniques as part of a UK development programme in this area. The paper describes the development programme which led to the introduction of competitive centrifuge enrichment technology by Urenco and discusses the areas where improvements have and will continue to be made in the centrifuge process. It also describes the laser development programme currently being undertaken in the UK. The paper concludes by discussing the relative merits of the various methods of uranium enrichment, with particular reference to the enrichment market likely to obtain over the rest of the century

  10. Advanced enrichment techniques

    International Nuclear Information System (INIS)

    Johnson, A.

    1987-01-01

    BNFL is in a unique position in that it has commercial experience of diffusion enrichment, and of centrifuge enrichment through its associate company Urenco. In addition BNFL is developing laser enrichment techniques as part of a UK development programme in this area. The paper describes the development programme which led to the introduction of competitive centrifuge enrichment technology by Urenco and discusses the areas where improvements have and will continue to be made in the centrifuge process. It also describes the laser development programme currently being undertaken in the UK. The paper concludes by discussing the relative merits of the various methods of uranium enrichment, with particular reference to the enrichment market likely to obtain over the rest of the century. (author)

  11. Chemical composition and fermentative parameters of heart of palm waste produced from Alexander Palm ensiled with chemical additives

    Directory of Open Access Journals (Sweden)

    Geraldo Fábio Viana Bayão

    Full Text Available ABSTRACT The objective of this study was to evaluate the chemical composition and the fermentative parameters of heart of palm waste produced from Alexander Palm, ensiled with chemical additives. Treatments consisted of silage of the sheath with or without calcium oxide. In the silage without calcium oxide, we evaluated the control silage (without additive and the silage enriched with 5.0 g kg−1 urea (urea. In the silage with calcium oxide, we evaluated the silage enriched with 5.0 g kg−1 calcium oxide (control and the silage enriched with 5.0 g kg−1 urea and 5.0 g kg−1 calcium oxide (urea. Experimental silos were distributed in a completely randomized design in a 2 × 2 factorial arrangement (inclusion or lack of lime × inclusion or lack of urea, with four replicates. Crude protein concentration was greater in the silages that received urea, whereas in the case of neutral detergent fiber and acid detergent fiber, the lowest levels were found in the control silage. Control silage had the lowest pH (3.75 and the silages that received lime displayed the lowest lactic acid content. Effluent losses were greater in the control silage and in the silage with lime (56.1 kg t−1 and 58.4 kg t−1, respectively. Silages prepared with waste from heart of palm production and enriched only with urea showed a better chemical composition and improved fermentation parameter estimates. We recommend the use of this waste only with additives that can improve the chemical characteristics of the forage. Without additives, unwanted fermentation processes may occur and compromise the quality of the silage.

  12. Juvenile psittacine environmental enrichment.

    Science.gov (United States)

    Simone-Freilicher, Elisabeth; Rupley, Agnes E

    2015-05-01

    Environmental enrichment is of great import to the emotional, intellectual, and physical development of the juvenile psittacine and their success in the human home environment. Five major types of enrichment include social, occupational, physical, sensory, and nutritional. Occupational enrichment includes exercise and psychological enrichment. Physical enrichment includes the cage and accessories and the external home environment. Sensory enrichment may be visual, auditory, tactile, olfactory, or taste oriented. Nutritional enrichment includes variations in appearance, type, and frequency of diet, and treats, novelty, and foraging. Two phases of the preadult period deserve special enrichment considerations: the development of autonomy and puberty. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. On the pathologically altered pulmonary pattern

    International Nuclear Information System (INIS)

    Ginzburg, M.A.; Kinoshenko, Yu.T.

    1982-01-01

    The notions ''normal'' and ''pathologically altered pulmonary pattern'' are specified. A grouping of lung pattern alterations based on morphopathogenetic features is provided: blood and lymphatic vascular alterations, changes in the bronchi, lung stroma, and combined alterations. Radiologic appearance of the altered pulmonary pattern is classified in keeping with the basic principles of an X-ray shade examination. The terms, such as ''enriching'', ''strengthening'', ''deformation'', etc., used for describing the pathologically altered pulmonary pattern are defined

  14. Uranium enrichment

    International Nuclear Information System (INIS)

    1989-01-01

    GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

  15. Nutrient enrichment is associated with altered nectar and pollen chemical composition in Succisa pratensis Moench and increased larval mortality of its pollinator Bombus terrestris L.

    Directory of Open Access Journals (Sweden)

    Tobias Ceulemans

    Full Text Available Pollinators are declining worldwide and possible underlying causes include disease, invasive pest species and large scale land use changes resulting in habitat loss and degradation. One particular cause of habitat degradation is the increased inflow of nutrients due to anthropogenic combustion processes and large scale application of agricultural fertilizers. This nutrient pollution has been shown to affect pollinators through the loss of nectar and pollen-providing plant species. However, it may also affect pollinators through altering the nectar and pollen chemical composition of plant species, hence influencing pollinator food quality. Here, we experimentally investigated the effect of nutrient enrichment on amino acid and sugar composition of nectar and pollen in the grassland plant Sucissa pratensis, and the subsequent colony size and larval mortality of the pollinating bumblebee Bombus terrestris. We found less of the essential amino acids glycine and arginine in the pollen of fertilized plants, and more arginine, ornithine and threonine in the pollen of control plants. Nectar glucose and pollen fructose levels were lower in fertilized plants as compared to control plants. Furthermore, bumblebee colonies visiting fertilized plants showed more dead larvae than colonies visiting control plants. Our results suggest that the fitness of bumblebees can be negatively affected by changes in their food quality following nutrient pollution. If similar patterns hold for other plant and pollinator species, this may have far reaching implications for the maintenance of pollination ecosystem services, as nutrient pollution continues to rise worldwide.

  16. Nutrient enrichment is associated with altered nectar and pollen chemical composition in Succisa pratensis Moench and increased larval mortality of its pollinator Bombus terrestris L.

    Science.gov (United States)

    Ceulemans, Tobias; Hulsmans, Eva; Vanden Ende, Wim; Honnay, Olivier

    2017-01-01

    Pollinators are declining worldwide and possible underlying causes include disease, invasive pest species and large scale land use changes resulting in habitat loss and degradation. One particular cause of habitat degradation is the increased inflow of nutrients due to anthropogenic combustion processes and large scale application of agricultural fertilizers. This nutrient pollution has been shown to affect pollinators through the loss of nectar and pollen-providing plant species. However, it may also affect pollinators through altering the nectar and pollen chemical composition of plant species, hence influencing pollinator food quality. Here, we experimentally investigated the effect of nutrient enrichment on amino acid and sugar composition of nectar and pollen in the grassland plant Sucissa pratensis, and the subsequent colony size and larval mortality of the pollinating bumblebee Bombus terrestris. We found less of the essential amino acids glycine and arginine in the pollen of fertilized plants, and more arginine, ornithine and threonine in the pollen of control plants. Nectar glucose and pollen fructose levels were lower in fertilized plants as compared to control plants. Furthermore, bumblebee colonies visiting fertilized plants showed more dead larvae than colonies visiting control plants. Our results suggest that the fitness of bumblebees can be negatively affected by changes in their food quality following nutrient pollution. If similar patterns hold for other plant and pollinator species, this may have far reaching implications for the maintenance of pollination ecosystem services, as nutrient pollution continues to rise worldwide.

  17. Isotope enrichment

    International Nuclear Information System (INIS)

    Lydtin, H-J.; Wilden, R.J.; Severin, P.J.W.

    1978-01-01

    The isotope enrichment method described is based on the recognition that, owing to mass diffusion and thermal diffusion in the conversion of substances at a heated substrate while depositing an element or compound onto the substrate, enrichment of the element, or a compound of the element, with a lighter isotope will occur. The cycle is repeated for as many times as is necessary to obtain the degree of enrichment required

  18. Chemical mechanical polishing of BTO thin film for vertical sidewall patterning of high-density memory capacitor

    International Nuclear Information System (INIS)

    Kim, Nam-Hoon; Ko, Pil-Ju; Seo, Yong-Jin; Lee, Woo-Sun

    2006-01-01

    Most high-k materials cannot to be etched easily. Problems such as low etch rate, poor sidewall angle, plasma damage, and process complexity have emerged in high-density DRAM fabrication. Chemical mechanical polishing (CMP) by the damascene process has been used to pattern high-k materials for high-density capacitor. Barium titanate (BTO) thin film, a typical high-k material, was polished with three types of silica slurry having different pH values. Sufficient removal rate with adequate selectivity to realize the pattern mask of tetra-ethyl ortho-silicate (TEOS) film for the vertical sidewall angle was obtained. The changes of X-ray diffraction pattern and dielectric constant by CMP process were negligible. Planarization was also achieved for the subsequent multilevel processes. Our new CMP approach will provide a guideline for effective patterning of high-k materials by CMP

  19. Ge-rich islands grown on patterned Si substrates by low-energy plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Bollani, M; Fedorov, A; Chrastina, D; Sordan, R; Picco, A; Bonera, E

    2010-01-01

    Si 1-x Ge x islands grown on Si patterned substrates have received considerable attention during the last decade for potential applications in microelectronics and optoelectronics. In this work we propose a new methodology to grow Ge-rich islands using a chemical vapour deposition technique. Electron-beam lithography is used to pre-pattern Si substrates, creating material traps. Epitaxial deposition of thin Ge films by low-energy plasma-enhanced chemical vapour deposition then leads to the formation of Ge-rich Si 1-x Ge x islands (x > 0.8) with a homogeneous size distribution, precisely positioned with respect to the substrate pattern. The island morphology was characterized by atomic force microscopy, and the Ge content and strain in the islands was studied by μRaman spectroscopy. This characterization indicates a uniform distribution of islands with high Ge content and low strain: this suggests that the relatively high growth rate (0.1 nm s -1 ) and low temperature (650 deg. C) used is able to limit Si intermixing, while maintaining a long enough adatom diffusion length to prevent nucleation of islands outside pits. This offers the novel possibility of using these Ge-rich islands to induce strain in a Si cap.

  20. Ge-rich islands grown on patterned Si substrates by low-energy plasma-enhanced chemical vapour deposition.

    Science.gov (United States)

    Bollani, M; Chrastina, D; Fedorov, A; Sordan, R; Picco, A; Bonera, E

    2010-11-26

    Si(1-x)Ge(x) islands grown on Si patterned substrates have received considerable attention during the last decade for potential applications in microelectronics and optoelectronics. In this work we propose a new methodology to grow Ge-rich islands using a chemical vapour deposition technique. Electron-beam lithography is used to pre-pattern Si substrates, creating material traps. Epitaxial deposition of thin Ge films by low-energy plasma-enhanced chemical vapour deposition then leads to the formation of Ge-rich Si(1-x)Ge(x) islands (x > 0.8) with a homogeneous size distribution, precisely positioned with respect to the substrate pattern. The island morphology was characterized by atomic force microscopy, and the Ge content and strain in the islands was studied by μRaman spectroscopy. This characterization indicates a uniform distribution of islands with high Ge content and low strain: this suggests that the relatively high growth rate (0.1 nm s(-1)) and low temperature (650 °C) used is able to limit Si intermixing, while maintaining a long enough adatom diffusion length to prevent nucleation of islands outside pits. This offers the novel possibility of using these Ge-rich islands to induce strain in a Si cap.

  1. Laser-assisted chemical vapor deposition setup for fast synthesis of graphene patterns

    Science.gov (United States)

    Zhang, Chentao; Zhang, Jianhuan; Lin, Kun; Huang, Yuanqing

    2017-05-01

    An automatic setup based on the laser-assisted chemical vapor deposition method has been developed for the rapid synthesis of graphene patterns. The key components of this setup include a laser beam control and focusing unit, a laser spot monitoring unit, and a vacuum and flow control unit. A laser beam with precision control of laser power is focused on the surface of a nickel foil substrate by the laser beam control and focusing unit for localized heating. A rapid heating and cooling process at the localized region is induced by the relative movement between the focalized laser spot and the nickel foil substrate, which causes the decomposing of gaseous hydrocarbon and the out-diffusing of excess carbon atoms to form graphene patterns on the laser scanning path. All the fabrication parameters that affect the quality and number of graphene layers, such as laser power, laser spot size, laser scanning speed, pressure of vacuum chamber, and flow rates of gases, can be precisely controlled and monitored during the preparation of graphene patterns. A simulation of temperature distribution was carried out via the finite element method, providing a scientific guidance for the regulation of temperature distribution during experiments. A multi-layer graphene ribbon with few defects was synthesized to verify its performance of the rapid growth of high-quality graphene patterns. Furthermore, this setup has potential applications in other laser-based graphene synthesis and processing.

  2. Applying and Developing Patterns in Teaching

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Eriksen, Ole

    2003-01-01

    A community of teachers and researchers within computer science has adopted the idea of patterns and developed a set of pedagogical patterns. These patterns capture best practices in teaching. From our research and teaching practice we have observed that pedagogical patterns are useful...... enriches the notion of pedagogical patterns. Inspired by conditions for learning we identify three values in teaching in the field of engineering-related educations. Further we present a value-based template for guidelines in teaching, causing a better understanding of the patterns and help teachers...

  3. Susceptibility patterns and the role of extracellular DNA in Staphylococcus epidermidis biofilm resistance to physico-chemical stress exposure.

    Science.gov (United States)

    Olwal, Charles Ochieng'; Ang'ienda, Paul Oyieng'; Onyango, David Miruka; Ochiel, Daniel Otieno

    2018-05-02

    Over 65% of human infections are ascribed to bacterial biofilms that are often highly resistant to antibiotics and host immunity. Staphylococcus epidermidis is the predominant cause of recurrent nosocomial and biofilm-related infections. However, the susceptibility patterns of S. epidermidis biofilms to physico-chemical stress induced by commonly recommended disinfectants [(heat, sodium chloride (NaCl), sodium hypochlorite (NaOCl) and hydrogen peroxide (H 2 O 2 )] in domestic and human healthcare settings remains largely unknown. Further, the molecular mechanisms of bacterial biofilms resistance to the physico-chemical stresses remain unclear. Growing evidence demonstrates that extracellular DNA (eDNA) protects bacterial biofilms against antibiotics. However, the role of eDNA as a potential mechanism underlying S. epidermidis biofilms resistance to physico-chemical stress exposure is yet to be understood. Therefore, this study aimed to evaluate the susceptibility patterns of and eDNA release by S. epidermidis biofilm and planktonic cells to physico-chemical stress exposure. S. epidermidis biofilms exposed to physico-chemical stress conditions commonly recommended for disinfection [heat (60 °C), 1.72 M NaCl, solution containing 150 μL of waterguard (0.178 M NaOCl) in 1 L of water or 1.77 M H 2 O 2 ] for 30 and 60 min exhibited lower log reductions of CFU/mL than the corresponding planktonic cells (p chemical stress induced by the four commonly recommended disinfectants than the analogous planktonic cells. Further, S. epidermidis biofilms enhanced eDNA release in response to the sub-lethal heat and oxidative stress exposure than the corresponding planktonic cells suggesting a role of eDNA in biofilms resistance to the physico-chemical stresses.

  4. Substrate-Driven Convergence of the Microbial Community in Lignocellulose-Amended Enrichments of Gut Microflora from the Canadian Beaver (Castor canadensis) and North American Moose (Alces americanus).

    Science.gov (United States)

    Wong, Mabel T; Wang, Weijun; Lacourt, Michael; Couturier, Marie; Edwards, Elizabeth A; Master, Emma R

    2016-01-01

    Strategic enrichment of microcosms derived from wood foragers can facilitate the discovery of key microbes that produce enzymes for the bioconversion of plant fiber (i.e., lignocellulose) into valuable chemicals and energy. In this study, lignocellulose-degrading microorganisms from the digestive systems of Canadian beaver (Castor canadensis) and North American moose (Alces americanus) were enriched under methanogenic conditions for over 3 years using various wood-derived substrates, including (i) cellulose (C), (ii) cellulose + lignosulphonate (CL), (iii) cellulose + tannic acid (CT), and (iv) poplar hydrolysate (PH). Substantial improvement in the conversion of amended organic substrates into biogas was observed in both beaver dropping and moose rumen enrichment cultures over the enrichment phases (up to 0.36-0.68 ml biogas/mg COD added), except for enrichments amended with tannic acid where conversion was approximately 0.15 ml biogas/mg COD added. Multiplex-pyrosequencing of 16S rRNA genes revealed systematic shifts in the population of Firmicutes, Bacteroidetes, Chlorobi, Spirochaetes, Chloroflexi, and Elusimicrobia in response to the enrichment. These shifts were predominantly substrate driven, not inoculum driven, as revealed by both UPGMA clustering pattern and OTU distribution. Additionally, the relative abundance of multiple OTUs from poorly defined taxonomic lineages increased from less than 1% to 25-50% in microcosms amended with lignocellulosic substrates, including OTUs from classes SJA-28, Endomicrobia, orders Bacteroidales, OPB54, and family Lachnospiraceae. This study provides the first direct comparison of shifts in microbial communities that occurred in different environmental samples in response to multiple relevant lignocellulosic carbon sources, and demonstrates the potential of enrichment to increase the abundance of key lignocellulolytic microorganisms and encoded activities.

  5. DNA-Encoded Dynamic Combinatorial Chemical Libraries.

    Science.gov (United States)

    Reddavide, Francesco V; Lin, Weilin; Lehnert, Sarah; Zhang, Yixin

    2015-06-26

    Dynamic combinatorial chemistry (DCC) explores the thermodynamic equilibrium of reversible reactions. Its application in the discovery of protein binders is largely limited by difficulties in the analysis of complex reaction mixtures. DNA-encoded chemical library (DECL) technology allows the selection of binders from a mixture of up to billions of different compounds; however, experimental results often show low a signal-to-noise ratio and poor correlation between enrichment factor and binding affinity. Herein we describe the design and application of DNA-encoded dynamic combinatorial chemical libraries (EDCCLs). Our experiments have shown that the EDCCL approach can be used not only to convert monovalent binders into high-affinity bivalent binders, but also to cause remarkably enhanced enrichment of potent bivalent binders by driving their in situ synthesis. We also demonstrate the application of EDCCLs in DNA-templated chemical reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Chemical evolution of the galactic disk

    International Nuclear Information System (INIS)

    Wyse, R.F.G.; Gilmore, G.

    1987-01-01

    The distribution of enriched material in the stars and gas of their Galaxy contains information pertaining to the chemical evolution of the Milky Way from its formation epoch to the present day, and provides general constraints on theories of galaxy formation. The separate stellar components of the Galaxy cannot readily be understood if treated in isolation, but a reasonably self-consistent model for Galactic chemical evolution may be found if one considers together the chemical properties of the extreme spheroid, thick disk and thin disk populations of the Galaxy. The three major stellar components of the Galaxy are characterized by their distinct spatial distributions, metallicity structure, and kinematics, with the newly-identified thick disk being approximately three times more massive than the classical metal-poor, non-rotating extreme spheroid. Stellar evolution in the thick disk straightforwardly provides the desired pre-enrichment for resolution of the thin disk G dwarf problem

  7. New generation enrichment monitoring technology for gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Ianakiev, Kiril D.; Alexandrov, Boian S.; Boyer, Brian D.; Hill, Thomas R.; Macarthur, Duncan W.; Marks, Thomas; Moss, Calvin E.; Sheppard, Gregory A.; Swinhoe, Martyn T.

    2008-01-01

    The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF 6 containing low enriched (approximately 4% 235 U) and highly enriched (above 20% 235 U) uranium. This instrument used the 22-keV line from a 109 Cd source as a transmission source to achieve a high sensitivity to the UF 6 gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF 6 product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

  8. Volume Reduction of Decommissioning Burnable Waste with Oxygen Enrich Incinerator

    International Nuclear Information System (INIS)

    Min, B. Y.; Yang, D. S.; Lee, K. W.; Choi, J. W.

    2016-01-01

    The incineration technology is an effective treatment method that contains hazardous chemicals as well as radioactive contamination. The volume reduction of the combustible wastes through the incineration technologies has merits from the view point of a decrease in the amount of waste to be disposed of resulting in a reduction of the disposal cost. Incineration is generally accepted as a method of reducing the volume of radioactive waste. The incineration technology is an effective treatment method that contains hazardous chemicals as well as radioactive contamination. This paper covers the general facility operation of an oxygen-enriched incinerator for the treatment of decommissioning wastes generated from a decommissioning project. The combustible wastes have been treated by the utilization of incinerator the capacity of the average 20 kg/hr. The decommissioning combustible waste of about 31 tons has been treated using Oxygen Enriched incinerator by at the end of 2016. The off-gas flow and temperature were maintained constant or within the desired range. The measured gases and particulate materials in the stack were considerably below the regulatory limits.

  9. Volume Reduction of Decommissioning Burnable Waste with Oxygen Enrich Incinerator

    Energy Technology Data Exchange (ETDEWEB)

    Min, B. Y.; Yang, D. S.; Lee, K. W.; Choi, J. W. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The incineration technology is an effective treatment method that contains hazardous chemicals as well as radioactive contamination. The volume reduction of the combustible wastes through the incineration technologies has merits from the view point of a decrease in the amount of waste to be disposed of resulting in a reduction of the disposal cost. Incineration is generally accepted as a method of reducing the volume of radioactive waste. The incineration technology is an effective treatment method that contains hazardous chemicals as well as radioactive contamination. This paper covers the general facility operation of an oxygen-enriched incinerator for the treatment of decommissioning wastes generated from a decommissioning project. The combustible wastes have been treated by the utilization of incinerator the capacity of the average 20 kg/hr. The decommissioning combustible waste of about 31 tons has been treated using Oxygen Enriched incinerator by at the end of 2016. The off-gas flow and temperature were maintained constant or within the desired range. The measured gases and particulate materials in the stack were considerably below the regulatory limits.

  10. Limitations of patterning thin films by shadow mask high vacuum chemical vapor deposition

    International Nuclear Information System (INIS)

    Reinke, Michael; Kuzminykh, Yury; Hoffmann, Patrik

    2014-01-01

    A key factor in engineering integrated devices such as electro-optic switches or waveguides is the patterning of high quality crystalline thin films into specific geometries. In this contribution high vacuum chemical vapor deposition (HV-CVD) was employed to grow titanium dioxide (TiO 2 ) patterns onto silicon. The directed nature of precursor transport – which originates from the high vacuum environment during the process – allows shading certain regions on the substrate by shadow masks and thus depositing patterned thin films. While the use of such masks is an emerging field in stencil or shadow mask lithography, their use for structuring thin films within HV-CVD has not been reported so far. The advantage of the employed technique is the precise control of lateral spacing and of the distance between shading mask and substrate surface which is achieved by manufacturing them directly on the substrate. As precursor transport takes place in the molecular flow regime, the precursor impinging rates (and therefore the film growth rates) on the surface can be simulated as function of the reactor and shading mask geometry using a comparatively simple mathematical model. In the current contribution such a mathematical model, which predicts impinging rates on plain or shadow mask structured substrates, is presented. Its validity is confirmed by TiO 2 -deposition on plain silicon substrates (450 °C) using titanium tetra isopropoxide as precursor. Limitations of the patterning process are investigated by the deposition of TiO 2 on structured substrates and subsequent shadow mask lift-off. The geometry of the deposits is according to the mathematical model. Shading effects due to the growing film enables to fabricate deposits with predetermined variations in topography and non-flat top deposits which are complicated to obtain by classical clean room processes. As a result of the enhanced residual pressure of decomposition products and titanium precursors and the

  11. Enrichment of 13C by chemical exchange between CO2 and amine carbamate in nonaqueous solvent

    International Nuclear Information System (INIS)

    Raica, Paula; Axente, D.

    2009-01-01

    Full text: Enrichment of 13 C by chemical exchange between CO 2 and amine carbamate in nonaqueous solvent has been mathematically modelled in two ways. The height equivalent to a theoretical plate and steady-state separation, based on the two models, have been obtained. If only the isotopic exchange between CO 2 gas and amine carbamate is considered, the model can estimate the process performance for pressures close to the atmospheric one and room temperature. For process analysis at pressures higher than atmospheric one and lower temperatures, a two-step model has been developed. Using the two models the effects of pressure increasing have been studied. At atmospheric pressure and 2M DNBA - methanol solution the isotope transfer rate is lower at 5 deg. C than at 25 deg. C. The isotope transfer is supported by pressure increasing according the increase of the CO 2 concentration in the amine solution. A lower temperature determines also an increase in the concentration of dissolved CO 2 and, for this reason, at 5 deg.C and higher pressures the isotope exchange reaction rate is higher than at 25 deg. C, HETP being lower with more than 100% at 5 deg. C than at 25 deg. C. (authors)

  12. Chemical fingerprints of He-sdO stars

    Directory of Open Access Journals (Sweden)

    Schindewolf Markus

    2018-02-01

    Full Text Available The chemical composition of helium-rich hot subluminous O stars plays an important role to understand and model their formation history. We present a spectroscopic analysis of four He-sdO stars,CD-31° 4800, [CW83] 0904- 02, LSS 1274 and LS IV +10° 9. The analysis is based on archival optical and UV high-resolution spectra. We used Tlusty200/Synspec48 to compute line blanketed non-LTE model atmospheres and their corresponding synthetic spectra and derive the atmospheric parameters as well as the abundances of the most prominent elements. All stars have helium-dominated atmospheres with hardly any hydrogen and temperatures between 42000 K and 47000 K while their surface gravity spans between log g = 5.4 and 5.7. CD-31° 4800 shows an enrichment of nitrogen and the characteristic pattern of hydrogen burning via the CNO-cycle, while the rest of the elements have about the solar abundance. This points to the slow merger of two helium white dwarfs as the most likely origin for this system. The other three stars are enriched in carbon, nitrogen and neon while their intermediate mass element’s abundance scatters around the solar value. They were possibly formed in the deep mixing late hot flasher scenario.

  13. Chemical fingerprints of He-sdO stars

    Science.gov (United States)

    Schindewolf, Markus; Németh, Peter; Heber, Ulrich; Battich, Tiara; Miller Bertolami, Marcelo M.; Latour, Marilyn

    2018-02-01

    The chemical composition of helium-rich hot subluminous O stars plays an important role to understand and model their formation history. We present a spectroscopic analysis of four He-sdO stars,CD-31° 4800, [CW83] 0904- 02, LSS 1274 and LS IV +10° 9. The analysis is based on archival optical and UV high-resolution spectra. We used Tlusty200/Synspec48 to compute line blanketed non-LTE model atmospheres and their corresponding synthetic spectra and derive the atmospheric parameters as well as the abundances of the most prominent elements. All stars have helium-dominated atmospheres with hardly any hydrogen and temperatures between 42000 K and 47000 K while their surface gravity spans between log g = 5.4 and 5.7. CD-31° 4800 shows an enrichment of nitrogen and the characteristic pattern of hydrogen burning via the CNO-cycle, while the rest of the elements have about the solar abundance. This points to the slow merger of two helium white dwarfs as the most likely origin for this system. The other three stars are enriched in carbon, nitrogen and neon while their intermediate mass element's abundance scatters around the solar value. They were possibly formed in the deep mixing late hot flasher scenario.

  14. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Thomas, D.C.; Gagne, R.W.

    1978-01-01

    The following topics are covered: the status of the Government's existing uranium enrichment services contracts, natural uranium requirements based on the latest contract information, uncertainty in predicting natural uranium requirements based on uranium enrichment contracts, and domestic and foreign demand assumed in enrichment planning

  15. Effect of saffron (Crocus sativus L.) enrichment on antioxidant and sensorial properties of wheat flour pasta.

    Science.gov (United States)

    Armellini, R; Peinado, I; Pittia, P; Scampicchio, M; Heredia, A; Andres, A

    2018-07-15

    Saffron, used in cookery as a flavouring and colouring agent, is well-known for its antioxidant and beneficial health properties. In the present work, the effect of saffron addition (0-control, 0.1, 0.2 and 0.4%, w/w) in the formulation of fresh pasta was evaluated on textural, physical-chemical, and sensory properties of the cooked product. Content and retention of the bioactive molecules of saffron (crocins) were evaluated by HPLC along with the corresponding antioxidant activity of enriched pasta. The presence of saffron significantly influenced textural and physical-chemical properties of pasta. Higher saffron concentrations enhanced the antioxidant activity of pasta with the higher values of crocins in samples enriched with 0.4% saffron extract even after 3 min of cooking (4.23-5.06 mg/g db). Sensory analysis showed an increased acceptability of the saffron enriched pasta for all descriptors selected (visual aspect, colour, aroma, taste, chewiness, hardness, gumminess and overall acceptability). Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Growth and characterization of isotopically enriched 70Ge and 74Ge single crystals

    International Nuclear Information System (INIS)

    Itoh, K.

    1992-10-01

    Isotopically enriched 70 Ge and 74 Ge single crystals were successfully gown by a newly developed vertical Bridgman method. The system allows us to reliably grow high purity Ge single crystals of approximately 1 cm 3 volume. To our knowledge, we have grown the first 70 Ge single crystal. The electrically active chemical impurity concentration for both crystals was found to be ∼2 x cm -3 which is two order of magnitude better that of 74 Ge crystals previously grown by two different groups. Isotopic enrichment of the 70 Ge and the 74 Ge crystals is 96.3% and 96.8%, respectively. The residual chemical impurities present in both crystals were identified as phosphorus, copper, aluminum, and indium. A wide variety of experiments which take advantage of the isotopic purity of our crystals are discussed

  17. Automated nuclear fuel rod pattern loading system

    International Nuclear Information System (INIS)

    Lambert, D.V.; Nyland, T.W.; Byers, J.W.; Haley, D.E. Jr.; Cioffi, J.V.

    1990-01-01

    This patent describes an apparatus for loading fuel rods in a desired pattern. It comprises: a carousel having a plurality of movable gondolas for stocking thereon fuel rods of known enrichments; an elongated magazine defining a matrix of elongated slots being open at their forward ends for receiving fuel rods; a workstation defining a fuel rod feed path; and a holder and indexing mechanism for movably supporting the magazine and being actuatable for moving the magazine along X-Y axes to successively align one at a time selected ones of the slots with the feed path for loading in the magazine the successive fuel rods in a desired enrichment pattern

  18. Other enrichment related contracts

    International Nuclear Information System (INIS)

    Hall, J.C.

    1978-01-01

    In addition to long-term enrichment contracts, DOE has other types of contracts: (1) short-term, fixed-commitment enrichment contract; (2) emergency sales agreement for enriched uranium; (3) feed material lease agreement; (4) enriched uranium storage agreement; and (5) feed material usage agreement

  19. Physicochemical and sensorial characteristics of noodle enriched with oyster mushroom (Pleorotus ostreatus) powder

    Science.gov (United States)

    Wahyono, A.; Novianti; Bakri, A.; Kasutjianingati

    2018-01-01

    Oyster Mushroom is a mushroom that can be used for food and medicine. It contains highly nutritious and functional substances such as statins and beta-glucan. A comprehensive evaluation of noodle-enriched with Oyster Mushroom powder has not been performed so far. In this study, we performed a comprehensive evaluation of noodle-enriched with Oyster Mushroom powder. The aim of this study was to assess the effects of enrichment of Oyster Mushroom Powder (OMP) on the quality of noodle. The quality of noodle was evaluated based on physical, chemical and sensorial characteristics. This study was done by substituting wheat flour with OMP at the level of 0 (control); 5; 7.5; 10; 12.5; and 15%. The results showed that OMP significantly affected (Pvalues of noodle.

  20. Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

    International Nuclear Information System (INIS)

    Liu, W.X.; Li, X.D.; Shen, Z.G.; Wang, D.C.; Wai, O.W.H.; Li, Y.S.

    2003-01-01

    Multivariate statistical analysis identified the heavy metal accumulation layers of sediment profiles and showed the various sources of metals in the estuary. - The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206 Pb/ 207 Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary

  1. [Hydroxylamine conversion by anammox enrichment].

    Science.gov (United States)

    Hu, Anhui; Zheng, Ping; Lu, Huifeng; Ding, Shuang; Wang, Caihua

    2010-04-01

    Hydroxylamine is an important intermediate product of anammox. This study was focused on the characteristics of hydroxylamine and nitrite conversions by anammox enrichment. The changes of nitrogenous substrates and related products with time were measured using batch tests with anammox enrichment as inoculum. Since hydroxylamine didn't react with nitrite in uninoculated control culture, these two compounds were chemically stable. Both of them decreased with time in anammox enrichment inoculated cultures, in which ammonia as intermediate product would be produced and converted with the maximum concentration being 0.338 mg/L. The total nitrogen concentration decreased from 4.694 mmol/L to 0.812 mmol/L with conversion rate 82.7% in the end. When hydroxylamine and nitrite concentrations were about 2.5 mmol/L respectively, the maximum specific sludge conversion rates of hydroxylamine was 0.535 mmol/(gVSS.h), which was 1.81 times bigger than that of ammonia in ammonia reaction system; the maximum specific sludge rate of total nitrogen was slightly higher than that in ammonia reaction system. When hydroxylamine concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 26.7% and 120.7% respectively; and the maximum ammonia accumulated was 1.810 mmol/L. When nitrite concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 6.9% and 9.0% respectively; and the maximum ammonia accumulated was 0.795 mmol/L. Anammox enrichment was capable of converting hydroxylamine and nitrite simultaneously and had the higher conversion rate of hydroxylamine than ammonia conversion rate. Hydroxylamine and nitrite conversion rates were less affected by increase in nitrite concentration, but more significantly influenced by increase in hydroxylamine. The maximum ammonia concentration accumulated would rise as the result of increasing both hydroxylamine and nitrite. The result of experiment was consistent with pathway

  2. Tritium enrichment from aqueous solutions using cryosublimation of mono- and polysaccharides

    International Nuclear Information System (INIS)

    Wierczinski, B.; Muellen, G.; Rosenhauer, S.

    2008-01-01

    Cryosublimation is one technique, which allows the accumulation of tritium from aqueous solutions using certain chemical compounds. After studying several inorganic compounds such as zeolites and metal salts, as well as some humic substances, we have now investigated several mono- and polysaccharides, such as glucose, maltose, galactose, starch, agar, and gelatine. Except for starch all of the above mentioned compounds showed a clear enrichment of tritium. The highest value was reached for Agartine, which gave an enrichment factor of 6.2. Since mono- and polysaccharides form weak hydrogen bonds, these results prove again our theory that tritium is preferably accumulated in exchangeable hydrogen bonds. (author)

  3. Laterally Stitched Heterostructures of Transition Metal Dichalcogenide: Chemical Vapor Deposition Growth on Lithographically Patterned Area

    KAUST Repository

    Li, Henan

    2016-10-31

    Two-dimensional transition metal dichalcogenides (TMDCs) have shown great promise in electronics and optoelectronics due to their unique electrical and optical properties. Heterostructured TMDC layers such as the laterally stitched TMDCs offer the advantages of better electronic contact and easier band offset tuning. Here, we demonstrate a photoresist-free focused ion beam (FIB) method to pattern as-grown TMDC monolayers by chemical vapor deposition, where the exposed edges from FIB etching serve as the seeds for growing a second TMDC material to form desired lateral heterostructures with arbitrary layouts. The proposed lithographic and growth processes offer better controllability for fabrication of the TMDC heterostrucuture, which enables the construction of devices based on heterostructural monolayers. © 2016 American Chemical Society.

  4. Prioritising lexical patterns to increase axiomatisation in biomedical ontologies. The role of localisation and modularity.

    Science.gov (United States)

    Quesada-Martínez, M; Fernández-Breis, J T; Stevens, R; Mikroyannidi, E

    2015-01-01

    This article is part of the Focus Theme of METHODS of Information in Medicine on "Managing Interoperability and Complexity in Health Systems". In previous work, we have defined methods for the extraction of lexical patterns from labels as an initial step towards semi-automatic ontology enrichment methods. Our previous findings revealed that many biomedical ontologies could benefit from enrichment methods using lexical patterns as a starting point.Here, we aim to identify which lexical patterns are appropriate for ontology enrichment, driving its analysis by metrics to prioritised the patterns. We propose metrics for suggesting which lexical regularities should be the starting point to enrich complex ontologies. Our method determines the relevance of a lexical pattern by measuring its locality in the ontology, that is, the distance between the classes associated with the pattern, and the distribution of the pattern in a certain module of the ontology. The methods have been applied to four significant biomedical ontologies including the Gene Ontology and SNOMED CT. The metrics provide information about the engineering of the ontologies and the relevance of the patterns. Our method enables the suggestion of links between classes that are not made explicit in the ontology. We propose a prioritisation of the lexical patterns found in the analysed ontologies. The locality and distribution of lexical patterns offer insights into the further engineering of the ontology. Developers can use this information to improve the axiomatisation of their ontologies.

  5. Analysis of copper-nickel ores by gamma-gamma method in ore enrichment works

    International Nuclear Information System (INIS)

    Bol'shakov, A.Yu.; Tovstenko, Yu.G.; Chinskij, E.B.; Eliseev, G.I.

    1973-01-01

    The paper presents experimental data on continuous gamma-gamma assay of copper-nickel ores on conveyor belts and of dry discrete samples of classifier overflow at the enrichment plants of the Pechenganikel' group. The relative errors are given of the results of comparison of two-hour rapid analyses and shift and 24-hour chemical analyses of classifier overflow samples with the figures for gamma-gamma assay. The factors affecting the accuracy of the latter technique are elucidated. Practical recommendations are given on the use of this technique at the above enrichment plants. (author)

  6. Enrichment of reactive macerals in coal: its characterization and utilization in coke making

    Science.gov (United States)

    Nag, Debjani; Kopparthi, P.; Dash, P. S.; Saxena, V. K.; Chandra, S.

    2018-01-01

    Macerals in coal are of different types: reactive and inert. These macerals are differ in their physical and chemical properties. Column flotation method has been used to separate the reactive macerals in a non-coking coal. The enriched coal is then characterized in order to understand the changes in the coking potential by different techniques. It is then used in making of metallurgical coke by proper blending with other coals. Enriched coal enhance the properties of metallurgical coke. This shows a path of utilization of non-coking coal in metallurgical coke making.

  7. Magnesium enriched lactic acid bacteria as a carrier for probiotic ice cream production.

    Science.gov (United States)

    Góral, Małgorzata; Kozłowicz, Katarzyna; Pankiewicz, Urszula; Góral, Dariusz

    2018-01-15

    The following strains of bacteria: Lactobacillus rhamnosus B 442, Lactobacillus rhamnosus 1937, and Lactococcus lactis JBB 500 were enriched with magnesium ions using Pulsed Electric Fields. The potentially probiotic strains were added to the mixture in the DVS process and applied for the production of ice cream which were then analyzed physicochemically and microbiologically. Results showed that addition of bacteria enriched with magnesium did not change chemical parameters of the ice cream and did not affect the freezing process, meltability, and hardness. No significant differences were noted in colour of the samples. The ice cream with addition of bacteria enriched with magnesium had higher adhesiveness. The results of viability determination showed that the total number of microorganisms in the ice cream was higher than in the starter cultures. Viability of the bacteria enriched with magnesium in the obtained ice cream was lower in comparison to the control samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. On-Line Enrichment Monitor for UF{sub 6} Gas Centrifuge Enrichment Plant

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, K. D.; Boyer, B.; Favalli, A.; Goda, J. M.; Hill, T.; Keller, C.; Lombardi, M.; Paffett, M.; MacArthur, D. W.; McCluskey, C.; Moss, C. E.; Parker, R.; Smith, M. K.; Swinhoe, M. T. [Los Alamos National Laboratory, Los Alamos (United States)

    2012-06-15

    This paper is a continuation of the Advanced Enrichment Monitoring Technology for UF{sub 6} Gas Centrifuge Enrichment Plant (GCEP) work, presented in the 2010 IAEA Safeguards Symposium. Here we will present the system architecture for a planned side-by-side field trial test of passive (186-keV line spectroscopy and pressure-based correction for UF{sub 6} gas density) and active (186-keV line spectroscopy and transmission measurement based correction for UF{sub 6} gas density) enrichment monitoring systems in URENCO's enrichment plant in Capenhurst. Because the pressure and transmission measurements of UF{sub 6} are complementary, additional information on the importance of the presence of light gases and the UF{sub 6} gas temperature can be obtained by cross-correlation between simultaneous measurements of transmission, pressure and 186-keV intensity. We will discuss the calibration issues and performance in the context of accurate, on-line enrichment measurement. It is hoped that a simple and accurate on-line enrichment monitor can be built using the UF{sub 6} gas pressure provided by the Operator, based on online mass spectrometer calibration, assuming a negligible (a small fraction of percent) contribution of wall deposits. Unaccounted-for wall deposits present at the initial calibration will lead to unwanted sensitivity to changes in theUF{sub 6} gas pressure and thus to error in the enrichment results. Because the accumulated deposits in the cascade header pipe have been identified as an issue for Go/No Go measurements with the Cascade Header Enrichment Monitor (CHEM) and Continuous Enrichment Monitor (CEMO), it is important to explore their effect. Therefore we present the expected uncertainty on enrichment measurements obtained by propagating the errors introduced by deposits, gas density, etc. and will discuss the options for a deposit correction during initial calibration of an On-Line Enrichment Monitor (OLEM).

  9. Atrazine and its metabolites degradation in mineral salts medium and soil using an enrichment culture.

    Science.gov (United States)

    Kumar, Anup; Singh, Neera

    2016-03-01

    An atrazine-degrading enrichment culture was used to study degradation of atrazine metabolites viz. hydroxyatrazine, deethylatrazine, and deisopropylatrazine in mineral salts medium. Results suggested that the enrichment culture was able to degrade only hydroxyatrazine, and it was used as the sole source of carbon and nitrogen. Hydroxyatrazine degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as the additional sources of carbon and nitrogen, respectively. The enrichment culture could degrade high concentrations of atrazine (up to 110 μg/mL) in mineral salts medium, and neutral pH was optimum for atrazine degradation. Further, except in an acidic soil, enrichment culture was able to degrade atrazine in three soil types having different physico-chemical properties. Raising the pH of acidic soil to neutral or alkaline enabled the enrichment culture to degrade atrazine suggesting that acidic pH inhibited atrazine-degrading ability. The study suggested that the enrichment culture can be successfully utilized to achieve complete degradation of atrazine and its persistent metabolite hydroxyatrazine in the contaminated soil and water.

  10. Historical review of CEA researches on uranium enrichment

    International Nuclear Information System (INIS)

    Camarcat, N.

    1997-01-01

    The various uranium enrichment processes that have been studied at the CEA since 1953 are briefly reviewed: gaseous diffusion (which led to the construction of EURODIF plant), chemical treatments (which were abandoned in 1988 for cost reasons), gaseous ultracentrifugation, electromagnetic processes, laser techniques (since 1980) and especially the SILVA technique (atomic vapour laser isotopic separation) which could take the place of the gaseous diffusion technique when the EURODIF plant will need to be renewed before 2010

  11. Effects of grinding on properties of Mg-PSZ ceramics prepared by the surface enrichment of zirconia powders

    International Nuclear Information System (INIS)

    Deb, S.; Das, S.R.

    1995-01-01

    Commercial grade zirconia powders of mean particle size of 3.21 microns were super-ground in wet condition in alcoholic medium in a Planetary Ball-Mill for 12-hours using a zirconia pot as well as balls, in order to avoid contaminations from the grinding media. Sedigraph analysis data show the mean particle sizes within the range of 0.4 to 0.2 micron. The super-ground zirconia powders were then treated with appropriate acid and alkali solutions in order to enrich the surfaces of zirconia powders. The chemical analysis reports depict the enrichment phenomena of the processed zirconia powders. Magnesium oxide of different mole percentages (3 to 9%) have been incorporated to the above super-ground and enriched zirconia powder and green specimens were prepared by pressing with a suitable pressure of 200 MPa to yield the green compaction density of 3.06 gm/cm 3 . The compacted green specimens were sintered without pressure at 1,480 C in air followed by normal cooling. X-ray diffraction patterns of the above sintered and cooled specimens have confirmed the formation of Mg-PSZ ceramics with 40% tetragonal phase. The sintered PSZ-products have shown very good surface properties but at the cost of transverse rupture strength. The effects of grinding were observed on the above Mg-PSZ ceramics which exhibit very little change in the tetragonal phase even after 30-minutes of grinding with a 60-mesh diamond wheel at a normal pressure of 4 kg/cm 2

  12. Status of stable isotope enrichment, products, and services at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Aaron, W.S.; Tracy, J.G.; Collins, E.D.

    1997-01-01

    The Oak Ridge national laboratory (ORNL) has been supplying enriched stable and radioactive isotopes to the research, medical, and industrial communities for over 50 y. Very significant changes have occurred in this effort over the past several years, and, while many of these changes have had a negative impact on the availability of enriched isotopes, more recent developments are actually improving the situation for both the users and the producers of enriched isotopes. ORNL is still a major producer and distributor of radioisotopes, but future isotope enrichment operations to be conducted at the isotope enrichment facility (IEF)fwill be limited to stable isotopes. Among the positive changes in the enriched stable isotope area are a well-functioning, long-term contract program, which offers stability and pricing advantages; the resumption of calutron operations; the adoption of prorated conversion charges, which greatly improves the pricing of isotopes to small users; ISO 9002 registration of the IEF's quality management system; and a much more customer-oriented business philosophy. Efforts are also being made to restore and improve upon the extensive chemical and physical form processing capablities that once existed in the enriched stable isotope program. Innovative ideas are being pursued in both technical and administrative areas to encourage the beneficial use of enriched stable isotopes and the development of related technologies. (orig.)

  13. Status of stable isotope enrichment, products, and services at the Oak Ridge National Laboratory

    Science.gov (United States)

    Scott Aaron, W.; Tracy, Joe G.; Collins, Emory D.

    1997-02-01

    The Oak Ridge National Laboratory (ORNL) has been supplying enriched stable and radioactive isotopes to the research, medical, and industrial communities for over 50 y. Very significant changes have occurred in this effort over the past several years, and, while many of these changes have had a negative impact on the availability of enriched isotopes, more recent developments are actually improving the situation for both the users and the producers of enriched isotopes. ORNL is still a major producer and distributor of radioisotopes, but future isotope enrichment operations to be conducted at the Isotope Enrichment Facility (IEF) will be limited to stable isotopes. Among the positive changes in the enriched stable isotope area are a well-functioning, long-term contract program, which offers stability and pricing advantages; the resumption of calutron operations; the adoption of prorated conversion charges, which greatly improves the pricing of isotopes to small users; ISO 9002 registration of the IEF's quality management system; and a much more customer-oriented business philosophy. Efforts are also being made to restore and improve upon the extensive chemical and physical form processing capablities that once existed in the enriched stable isotope program. Innovative ideas are being pursued in both technical and administrative areas to encourage the beneficial use of enriched stable isotopes and the development of related technologies.

  14. Status of stable isotope enrichment, products, and services at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Aaron, W.S.; Tracy, J.G.; Collins, E.D.

    1996-01-01

    The Oak Ridge National Laboratory (ORNL) has been supplying enriched stable and radioactive isotopes to the research, medical, and industrial communities for over 50 years. Very significant changes have occurred in this effort over the past several years, and, while many of these changes have had a negative impact on the availability of enriched isotopes, more recent developments are actually improving the situation for both the users and the producers of enriched isotopes. ORNL is still a major producer and distributor of radioisotopes, but future isotope enrichment operations conducted at the Isotope Enrichment Facility (IEF) will be limited to stable isotopes. Among the positive changes in the enriched stable isotope area are a well-functioning, long-term contract program, which offers stability and pricing advantages; the resumption of calutron operations; the adoption of prorated conversion charges, which greatly improves the pricing of isotopes to small users; SIO 9002 registration of the IEF's quality management system; and a much more customer-oriented business philosophy. Efforts are also being made to restore and improve upon the extensive chemical and physical form processing capabilities that once existed in the enriched stable isotope program. Innovative ideas are being pursued in both technical and administrative areas to encourage the beneficial use of enriched stable isotopes and the development of related technologies

  15. Origin of enormous trace metal enrichments in weathering mantles of Jurassic carbonates: evidence from Sr, Nd and Pb isotopes

    Science.gov (United States)

    Hissler, C.; Stille, P.; Juilleret, J.; Iffly, J.; Perrone, T.; Morvan, G.

    2013-12-01

    Weathering mantels are widespread worldwide and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved carbonate rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual content of associated trace elements in this type of weathering mantle. For instance, these enrichments can represent about five times the content of the underlying Bajocian to Oxfordian limestone/marl complexes, which have been relatively poorly studied compared to weathering mantle developed on magmatic bedrocks. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources (saprolite, Bajocian silty marls and limestones, atmospheric particles deposition...). Of special interest has also been the origin of trace metals and the processes causing their enrichments. Especially Rare Earth Element (REE) distribution patterns and Sr, Nd and Pb isotope ratios are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments shall help to identify mobile phases in the soil system. This may inform on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. Trace metal migration and enrichments were studied on a cambisol developing on an underlying Jurassic limestone. The base is strongly enriched among others in rare earth elements (ΣREE: 2640ppm) or redox-sensitive elements such as Fe (44 wt.%), V (920ppm), Cr (700ppm), Zn (550ppm), As (260ppm), Co (45ppm

  16. Multisensor analyzer detector (MSAD) for low cost chemical and aerosol detection and pattern fusion

    Science.gov (United States)

    Swanson, David C.; Merdes, Daniel W.; Lysak, Daniel B., Jr.; Curtis, Richard C.; Lang, Derek C.; Mazzara, Andrew F.; Nicholas, Nicholas C.

    2002-08-01

    MSAD is being developed as a low-cost point detection chemical and biological sensor system designed around an information fusion inference engine that also allows additional sensors to be included in the detection process. The MSAD concept is based on probable cause detection of hazardous chemical vapors and aerosols of either chemical or biological composition using a small portable unit containing an embedded computer system and several integrated sensors with complementary capabilities. The configuration currently envisioned includes a Surface-Enhanced Raman Spectroscopy (SERS) sensor of chemical vapors and a detector of respirable aerosols based on Fraunhofer diffraction. Additional sensors employing Ion Mobility Spectrometry (IMS), Surface Acoustic Wave (SAW) detection, Flame Photometric Detection (FPD), and other principles are candidates for integration into the device; also, available commercial detectors implementing IMS, SAW, and FPD will be made accessible to the unit through RS232 ports. Both feature and decision level information fusion is supported using a Continuous Inference Network (CINET) of fuzzy logic. Each class of agents has a unique CINET with information inputs from a number of available sensors. Missing or low confidence sensor information is gracefully blended out of the output confidence for the particular agent. This approach constitutes a plug and play arrangement between the sensors and the information pattern recognition algorithms. We are currently doing simulant testing and developing out CINETs for actual agent testing at Edgewood Chemical and Biological Center (ECBC) later this year.

  17. Simulation of transportation of low enriched uranium solutions

    International Nuclear Information System (INIS)

    Hope, E.P.; Ades, M.J.

    1996-01-01

    A simulation of the transportation by truck of low enriched uranium solutions has been completed for NEPA purposes at the Savannah River Site. The analysis involves three distinct source terms, and establishes the radiological risks of shipment to three possible destinations. Additionally, loading accidents were analyzed to determine the radiological consequences of mishaps during handling and delivery. Source terms were developed from laboratory measurements of chemical samples from low enriched uranium feed materials being stored at SRS facilities, and from manufacturer data on transport containers. The transportation simulations were accomplished over the INTERNET using the DOE TRANSNET system at Sandia National Laboratory. The HIGHWAY 3.3 code was used to analyze routing scenarios, and the RADTRAN 4 code was used to analyze incident free and accident risks of transporting radiological materials. Loading accidents were assessed using the Savannah River Site AXAIR89Q and RELEASE 2 codes

  18. Laser photochemical studies on di-isopropyl ether for oxygen-18 enrichment

    International Nuclear Information System (INIS)

    Mathi, P.; Kumar, Awadhesh; Ghosh, Ayan; Nayak, A.K.; Parthasarathy, V.; Nataraju, V.; Jadhav, K.A.; Babu, K.Rajendra; Sarkar, S.K.

    2013-05-01

    Oxygen-18 is needed for the production of Fluorine-18 in medical cyclotron for use in positron emission tomography. This report deals with our work on Oxygen-18 selective photo dissociation of natural di-isopropyl ether under various conditions leading to various oxygen bearing products having different levels of 18 O enrichment. Apart from obtaining 18 O enrichment in products 2-propanol and acetaldehyde, we have observed unusually high enrichment (about 39%) in another photoproduct, acetone, as measured by mass spectrometry. This new finding is attributed to 18 O selective secondary reaction channels which is supported by molecular orbital calculations. The investigation required characterization and quantitative estimation of various chemical species, viz., di-isopropyl ether, acetaldehyde, acetone and isopropanol by various instrumental methods of analysis. These methods include gas chromatography, Fourier transform infrared spectrometry and quadrupole mass spectrometry. Detailed Gas Chromatographic (GC) studies summarize the interference problems encountered for quantitatively identifying different photo-products and establish the right experimental conditions for optimum separation. This exercise is extremely useful for an isotope enrichment scheme as it generates a valuable database to understand the processes involved for both selectivity enhancement and degradation. (author)

  19. Uranium Enrichment, an overview

    International Nuclear Information System (INIS)

    Coates, J.H.

    1994-01-01

    This general presentation on uranium enrichment will be followed by lectures on more specific topics including descriptions of enrichment processes and assessments of the prevailing commercial and industrial situations. I shall therefore avoid as much as possible duplications with these other lectures, and rather dwell on: some theoretical aspects of enrichment in general, underlying the differences between statistical and selective processes, a review and comparison between enrichment processes, remarks of general order regarding applications, the proliferation potential of enrichment. It is noteworthy that enrichment: may occur twice in the LWR fuel cycle: first by enriching natural uranium, second by reenriching uranium recovered from reprocessing, must meet LWR requirements, and in particular higher assays required by high burn up fuel elements, bears on the structure of the entire front part of the fuel cycle, namely in the conversion/reconversion steps only involving UF 6 for the moment. (author). tabs., figs., 4 refs

  20. Criteria for the safe storage of enriched uranium at the Y-12 Plant

    International Nuclear Information System (INIS)

    Cox, S.O.

    1995-07-01

    Uranium storage practices at US Department of Energy (DOE) facilities have evolved over a period spanning five decades of programmatic work in support of the nuclear deterrent mission. During this period, the Y-12 Plant in Oak Ridge, Tennessee has served as the principal enriched uranium facility for fabrication, chemical processing, metallurgical processing and storage. Recent curtailment of new nuclear weapons production and stockpile reduction has created significant amounts of enriched uranium available as a strategic resource which must be properly and safely stored. This standard specifies criteria associated with the safe storage of enriched uranium at the Y-12 Plant. Because programmatic needs, compliance regulations and desirable materials of construction change with time, it is recommended that these standards be reviewed and amended periodically to ensure that they continue to serve their intended purpose

  1. Enrichr: interactive and collaborative HTML5 gene list enrichment analysis tool.

    Science.gov (United States)

    Chen, Edward Y; Tan, Christopher M; Kou, Yan; Duan, Qiaonan; Wang, Zichen; Meirelles, Gabriela Vaz; Clark, Neil R; Ma'ayan, Avi

    2013-04-15

    System-wide profiling of genes and proteins in mammalian cells produce lists of differentially expressed genes/proteins that need to be further analyzed for their collective functions in order to extract new knowledge. Once unbiased lists of genes or proteins are generated from such experiments, these lists are used as input for computing enrichment with existing lists created from prior knowledge organized into gene-set libraries. While many enrichment analysis tools and gene-set libraries databases have been developed, there is still room for improvement. Here, we present Enrichr, an integrative web-based and mobile software application that includes new gene-set libraries, an alternative approach to rank enriched terms, and various interactive visualization approaches to display enrichment results using the JavaScript library, Data Driven Documents (D3). The software can also be embedded into any tool that performs gene list analysis. We applied Enrichr to analyze nine cancer cell lines by comparing their enrichment signatures to the enrichment signatures of matched normal tissues. We observed a common pattern of up regulation of the polycomb group PRC2 and enrichment for the histone mark H3K27me3 in many cancer cell lines, as well as alterations in Toll-like receptor and interlukin signaling in K562 cells when compared with normal myeloid CD33+ cells. Such analyses provide global visualization of critical differences between normal tissues and cancer cell lines but can be applied to many other scenarios. Enrichr is an easy to use intuitive enrichment analysis web-based tool providing various types of visualization summaries of collective functions of gene lists. Enrichr is open source and freely available online at: http://amp.pharm.mssm.edu/Enrichr.

  2. The patterns of energy use in the chemical industry

    International Nuclear Information System (INIS)

    Steinmeyer, D.

    1997-01-01

    This paper was sculpted from a report commissioned by the Department of Energy to assess the impact of proposed energy taxes on energy use by the US chemical industry. The discussion of energy taxes is eliminated here, however the broader discussion of the impact of energy prices on energy use is retained. The US chemical industry is currently the world leader by many important measures, such as technology contributions and employment. This leadership traces to a slate of advantages: science base, low cost energy, large market and economic/political stability. The focus of this paper is on the patterns of energy use: (1) There is an optimum economic trade of capital against energy. Industry optimizes this trade to lower its costs. For the large volume chemicals which dominate energy use, this tradable capital cost exceeds energy cost by a factor of 1.5. (2) The capital/energy trade follows clearly defined rules. The basic rules are rooted in thermodynamics. (3) An increase in energy prices would result in a drop in process energy use: a doubling of process energy prices would cut process energy use by approximately 1/3 but the capital cost would be in excess of $100 billion if driven into a short time span, such as 5 years. This is because of the long useful lifetime of capital facilities. (4) Process energy is about half the total energy use, with feedstock being the balance. Feedstock use is much less sensitive to price. Restated, the doubling of energy price will result in roughly a 1/6 reduction in total energy use. (5) Technology progress will also reduce energy use. This reduction is distinct from the impact of energy price. Technological progress will be at least as important in reducing energy use as will energy pricing, for the foreseeable future. (6) Technology progress can be sorted into two themes: (a) Learning curve improvements, which are almost inherent in the production process and the nature of competition; and (b) Breakthroughs that happen in a

  3. Novel fabrication of flexible graphene-based chemical sensors with heaters using soft lithographic patterning method.

    Science.gov (United States)

    Jung, Min Wook; Myung, Sung; Song, Wooseok; Kang, Min-A; Kim, Sung Ho; Yang, Cheol-Soo; Lee, Sun Sook; Lim, Jongsun; Park, Chong-Yun; Lee, Jeong-O; An, Ki-Seok

    2014-08-27

    We have fabricated graphene-based chemical sensors with flexible heaters for the highly sensitive detection of specific gases. We believe that increasing the temperature of the graphene surface significantly enhanced the electrical signal change of the graphene-based channel, and reduced the recovery time needed to obtain a normal state of equilibrium. In addition, a simple and efficient soft lithographic patterning process was developed via surface energy modification for advanced, graphene-based flexible devices, such as gas sensors. As a proof of concept, we demonstrated the high sensitivity of NO2 gas sensors based on graphene nanosheets. These devices were fabricated using a simple soft-lithographic patterning method, where flexible graphene heaters adjacent to the channel of sensing graphene were utilized to control graphene temperature.

  4. Uranium enrichment

    International Nuclear Information System (INIS)

    Mohrhauer, H.

    1982-01-01

    The separation of uranium isotopes in order to enrich the fuel for light water reactors with the light isotope U-235 is an important part of the nuclear fuel cycle. After the basic principals of isotope separation the gaseous diffusion and the centrifuge process are explained. Both these techniques are employed on an industrial scale. In addition a short review is given on other enrichment techniques which have been demonstrated at least on a laboratory scale. After some remarks on the present situation on the enrichment market the progress in the development and the industrial exploitation of the gas centrifuge process by the trinational Urenco-Centec organisation is presented. (orig.)

  5. United States uranium enrichment policies

    International Nuclear Information System (INIS)

    Roberts, R.W.

    1977-01-01

    ERDA's uranium enrichment program policies governing the manner in which ERDA's enrichment complex is being operated and expanded to meet customer requirements for separative work, research and development activities directed at providing technology alternatives for future enrichment capacity, and establishing the framework for additional domestic uranium enrichment capacity to meet the domestic and foreign nuclear industry's growing demand for enrichment services are considered. The ERDA enrichment complex consists of three gaseous diffusion plants located in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Today, these plants provide uranium enrichment services for commercial nuclear power generation. These enrichment services are provided under contracts between the Government and the utility customers. ERDA's program involves a major pilot plant cascade, and pursues an advanced isotope separation technique for the late 1980's. That the United States must develop additional domestic uranium enrichment capacity is discussed

  6. Blueprint for domestic uranium enrichment

    International Nuclear Information System (INIS)

    1981-01-01

    The AEC advisory committee on domestic production of uranium enrichment has studied for more than a year how to achieve the domestic enrichment of uranium by the construction and operation of a commercial enriching plant using centrifugal separation method, and the report was submitted to the Atomic Energy Commission on August 18, 1980. Japan has depended wholly on overseas services for her uranium enrichment needs, but the development of domestic enrichment has been carried on in parallel. The AEC decided to construct a uranium enrichment pilot plant using centrifuges, and it has been forwarded as a national project. The plant is operated by the Power Reactor and Nuclear Fuel Development Corp. since 1979. The capacity of the plant will be raised to approximately 75 ton SWU a year. The centrifuges already operated have provided the first delivery of fuel of about 1 ton for the ATR ''Fugen''. The demand-supply balance of uranium enrichment service, the significance of the domestic enrichment of uranium, the evaluation of uranium enrichment technology, the target for domestic enrichment plan, the measures to promote domestic uranium enrichment, and the promotion of the construction of a demonstration plant are reported. (Kako, I.)

  7. Reactive Imprint Lithography: Combined Topographical Patterning and Chemical Surface Functionalization of Polystyrene-block-poly(tert-butyl acrylate) Films

    NARCIS (Netherlands)

    Duvigneau, Joost; Cornelissen, Stijn; Bardajı´Valls, Nuria; Schönherr, Holger; Vancso, Gyula J.

    2009-01-01

    Here, reactive imprint lithography (RIL) is introduced as a new, one-step lithographic tool for the fabrication of large-area topographically patterned, chemically activated polymer platforms. Films of polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) are imprinted with PDMS master stamps at

  8. Can nutrient enrichment influence the invasion of Phragmites australis?

    Science.gov (United States)

    Uddin, Md Nazim; Robinson, Randall William

    2018-02-01

    Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO 3 - ), phosphorous (PO 4 3- ), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO 3 - ) and phosphorous (PO 4 3- ) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers. Copyright © 2017. Published by

  9. Automated extraction of chemical structure information from digital raster images

    Directory of Open Access Journals (Sweden)

    Shedden Kerby A

    2009-02-01

    Full Text Available Abstract Background To search for chemical structures in research articles, diagrams or text representing molecules need to be translated to a standard chemical file format compatible with cheminformatic search engines. Nevertheless, chemical information contained in research articles is often referenced as analog diagrams of chemical structures embedded in digital raster images. To automate analog-to-digital conversion of chemical structure diagrams in scientific research articles, several software systems have been developed. But their algorithmic performance and utility in cheminformatic research have not been investigated. Results This paper aims to provide critical reviews for these systems and also report our recent development of ChemReader – a fully automated tool for extracting chemical structure diagrams in research articles and converting them into standard, searchable chemical file formats. Basic algorithms for recognizing lines and letters representing bonds and atoms in chemical structure diagrams can be independently run in sequence from a graphical user interface-and the algorithm parameters can be readily changed-to facilitate additional development specifically tailored to a chemical database annotation scheme. Compared with existing software programs such as OSRA, Kekule, and CLiDE, our results indicate that ChemReader outperforms other software systems on several sets of sample images from diverse sources in terms of the rate of correct outputs and the accuracy on extracting molecular substructure patterns. Conclusion The availability of ChemReader as a cheminformatic tool for extracting chemical structure information from digital raster images allows research and development groups to enrich their chemical structure databases by annotating the entries with published research articles. Based on its stable performance and high accuracy, ChemReader may be sufficiently accurate for annotating the chemical database with links

  10. Enrichment Wastes' Processing of Manganiferous Ores with the Use of Mechanochemical Methods

    Science.gov (United States)

    Kubekova, Sholpan N.; Kapralova, Viktoria I.; Ibraimova, Gulnur T.; Batyrbayeva, Aigul A.

    2016-01-01

    The aim of the research is the study of the chemical and phase composition of enrichment wastes of manganiferous ore in Ushkatyn-III deposit and the synthesis of new materials by mechanochemical activation and subsequent heat treatment of the mechanical activation products. The use of XFA, infrared spectroscopy and electron probe microanalysis…

  11. AN IN-DEPTH STUDY OF THE ABUNDANCE PATTERN IN THE HOT INTERSTELLAR MEDIUM IN NGC 4649

    International Nuclear Information System (INIS)

    Loewenstein, Michael; Davis, David S.

    2012-01-01

    We present our X-ray imaging spectroscopic analysis of data from deep Suzaku and XMM-Newton Observatory exposures of the Virgo Cluster elliptical galaxy NGC 4649 (M60), focusing on the abundance pattern in the hot interstellar medium (ISM). All measured elements show a radial decline in abundance, with the possible exception of O. We construct steady-state solutions to the chemical evolution equations that include infall in addition to stellar mass return and Type Ia supernova (SNIa) enrichment, and consider recently published SNIa yields. By adjusting a single model parameter to obtain a match to the global abundance pattern in NGC 4649, we infer that introduction of subsolar metallicity external gas has reduced the overall ISM metallicity and diluted the effectiveness of SNIa to skew the pattern toward low α/Fe ratios, and estimate the combination of SNIa rate and level of dilution. Evidently, newly introduced gas is heated as it is integrated into, and interacts with, the hot gas that is already present. These results indicate a complex flow and enrichment history for NGC 4649, reflecting the continual evolution of elliptical galaxies beyond the formation epoch. The heating and circulation of accreted gas may help reconcile this dynamic history with the mostly passive evolution of elliptical stellar populations. In an Appendix, we examine the effects of the recent updated atomic database AtomDB in spectral fitting of thermal plasmas with hot ISM temperatures in the elliptical galaxy range.

  12. Promotion of uranium enrichment business

    International Nuclear Information System (INIS)

    Kurushima, Morihiro

    1981-01-01

    The Committee on Nuclear Power has studied on the basic nuclear power policy, establishing its five subcommittees, entrusted by the Ministry of Nternational Trade and Industry. The results of examination by the subcommittee on uranium enrichment business are given along with a report in this connection by the Committee. In order to establish the nuclear fuel cycle, the aspect of uranium enrichment is essential. The uranium enrichment by centrifugal process has proceeded steadily in Power Reactor and Nuclear Fuel Development Corporation. The following matters are described: the need for domestic uranium enrichment, the outlook for overseas enrichment services and the schedule for establishing domestic enrichment business, the current state of technology development, the position of the prototype enrichment plant, the course to be taken to establish enrichment business the main organization operating the prototype and commercial plants, the system of supplying centrifuges, the domestic conversion of natural uranium the subsidies for uranium enrichment business. (J.P.N.)

  13. Specific Affinity Enrichment of Electrochemically Cleaved Peptides Based on Cu(II)-Mediated Spirolactone Tagging

    NARCIS (Netherlands)

    Zhang, Tao; de Vries, Marcel P.; Permentier, Hjalmar P.; Bischoff, Rainer

    2017-01-01

    Specific digestion of proteins is an essential step for mass spectrometry-based proteomics, and the chemical labeling of the resulting peptides is often used for peptide enrichment or the introduction of desirable tags. Electrochemical oxidation yielding specific cleavage C-terminal to tyrosine

  14. Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg196 enrichment

    International Nuclear Information System (INIS)

    Grossman, M.W.

    1993-01-01

    The present invention is directed to a method of eliminating the cold spot zones presently used on Hg 196 isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment

  15. Blue-enriched office light competes with natural light as a zeitgeber.

    Science.gov (United States)

    Vetter, Céline; Juda, Myriam; Lang, Dieter; Wojtysiak, Andreas; Roenneberg, Till

    2011-09-01

    Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the "zeitgeber" light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.

  16. From high enriched to low enriched uranium fuel in research reactors

    Energy Technology Data Exchange (ETDEWEB)

    Van Den Berghe, S.; Leenaers, A.; Koonen, E.; Moons, F.; Sannen, L. [Nuclear Materials Science Institute, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium)

    2010-07-01

    Since the 1970's, global efforts have been going on to replace the high-enriched (>90% {sup 235}U), low-density UAlx research reactor fuel with high-density, low enriched (<20% {sup 235}U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U{sub 3}Si{sub 2} dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U{sub 3}Si{sub 2} (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development. (authors)

  17. From high enriched to low enriched uranium fuel in research reactors

    International Nuclear Information System (INIS)

    Van Den Berghe, S.; Leenaers, A.; Koonen, E.; Moons, F.; Sannen, L.

    2010-01-01

    Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235 U), low-density UAlx research reactor fuel with high-density, low enriched ( 235 U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U 3 Si 2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U 3 Si 2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development. (authors)

  18. Derived enriched uranium market

    International Nuclear Information System (INIS)

    Rutkowski, E.

    1996-01-01

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

  19. Zinc-enriched (ZEN) terminals in mouse spinal cord

    DEFF Research Database (Denmark)

    Jo, S M; Danscher, G; Schrøder, H D

    2000-01-01

    The general distribution of zinc-enriched (ZEN) terminals in mouse spinal cord was investigated at light microscopic level by means of zinc transporter-3 immunohistochemistry (ZnT3(IHC)) and zinc selenium autometallography (ZnSe(AMG)). Staining for ZnT3(IHC) corresponded closely to the Zn...... dendrites. These ZEN terminals in the ventral horn were in general larger than those in the dorsal horn. This is the first description of the pattern of ZEN terminals in mouse spinal cord....

  20. Polar ecosystem dynamics: recovery of communities from organic enrichment in McMurdo Sound, Antarctica.

    Science.gov (United States)

    Kim, Stacy; Hammerstom, Kamille K; Conlan, Kathleen E; Thurber, Andrew R

    2010-12-01

    Community structure and diversity are influenced by patterns of disturbance and input of food. In Antarctica, the marine ecosystem undergoes highly seasonal changes in availability of light and in primary production. Near research stations, organic input from human activities can disturb the regular productivity regime with a consistent input of sewage. McMurdo Sound has both high-productivity and low-productivity habitats, thereby providing an ideal test bed for community recovery dynamics under polar conditions. We used experimental manipulations of the subtidal communities to test the hypotheses that (1) benthic communities respond differently to disturbance from organic enrichment versus burial and (2) community response also varies in areas with different natural patterns of food supply. Both in low- and high-food habitats, the strongest community response was to organic enrichment and resulted in dominance of typical organic-enrichment specialists. In habitats with highly seasonal productivity, community response was predictable and recovery was rapid. In habitats with low productivity, community variability was high and caging treatments suggested that inconsistencies were due to patchy impacts by scavengers. In areas normally subject to regular organic enrichment, either from primary production or from further up the food web (defecation by marine mammals), recovery of benthic communities takes only years even in a polar system. However, a low-productivity regime is as common in near shore habitats around the continent; under these conditions, recovery of benthic communities from disturbance is likely to be much slower and follow a variable ecological trajectory.

  1. Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation.

    Science.gov (United States)

    Sutton, Nora B; Atashgahi, Siavash; Saccenti, Edoardo; Grotenhuis, Tim; Smidt, Hauke; Rijnaarts, Huub H M

    2015-01-01

    While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose

  2. Quantitative phase analysis using the whole-powder-pattern decomposition method. Pt. 1. Solution from knowledge of chemical compositions

    International Nuclear Information System (INIS)

    Toraya, H.; Tusaka, S.

    1995-01-01

    A new procedure for quantitative phase analysis using the whole-powder-pattern decomposition method is proposed. The procedure consists of two steps. In the first, the whole powder patterns of single-component materials are decomposed separately. The refined parameters of integrated intensity, unit cell and profile shape for respective phases are stored in computer data files. In the second step, the whole powder pattern of a mixture sample is fitted, where the parameters refined in the previous step are used to calculate the profile intensity. The integrated intensity parameters are, however, not varied during the least-squares fitting, while the scale factors for the profile intensities of individual phases are adjusted instead. Weight fractions are obtained by solving simultaneous equations, coefficients of which include the scale factors and the mass-absorption coefficients calculated from chemical formulas of respective phases. The procedure can be applied to all mixture samples, including those containing an amorphous material, if single-component samples with known chemical compositions and their approximate unit-cell parameters are provided. The procedure has been tested by using two-to five-component samples, giving average deviations of 1 to 1.5%. Optimum refinement conditions are discussed in connection with the accuracy of the procedure. (orig.)

  3. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal; Yang, Yang; Ng, Tien Khee; Dursun, Ibrahim; Shi, Dong; Saidaminov, Makhsud I.; Priante, Davide; Bakr, Osman; Ooi, Boon S.

    2015-01-01

    is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability

  4. In silico prediction of Tetrahymena pyriformis toxicity for diverse industrial chemicals with substructure pattern recognition and machine learning methods.

    Science.gov (United States)

    Cheng, Feixiong; Shen, Jie; Yu, Yue; Li, Weihua; Liu, Guixia; Lee, Philip W; Tang, Yun

    2011-03-01

    There is an increasing need for the rapid safety assessment of chemicals by both industries and regulatory agencies throughout the world. In silico techniques are practical alternatives in the environmental hazard assessment. It is especially true to address the persistence, bioaccumulative and toxicity potentials of organic chemicals. Tetrahymena pyriformis toxicity is often used as a toxic endpoint. In this study, 1571 diverse unique chemicals were collected from the literature and composed of the largest diverse data set for T. pyriformis toxicity. Classification predictive models of T. pyriformis toxicity were developed by substructure pattern recognition and different machine learning methods, including support vector machine (SVM), C4.5 decision tree, k-nearest neighbors and random forest. The results of a 5-fold cross-validation showed that the SVM method performed better than other algorithms. The overall predictive accuracies of the SVM classification model with radial basis functions kernel was 92.2% for the 5-fold cross-validation and 92.6% for the external validation set, respectively. Furthermore, several representative substructure patterns for characterizing T. pyriformis toxicity were also identified via the information gain analysis methods. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Corexit 9500 Enhances Oil Biodegradation and Changes Active Bacterial Community Structure of Oil-Enriched Microcosms

    OpenAIRE

    Techtmann, Stephen M.; Zhuang, Mobing; Campo, Pablo; Holder, Edith; Elk, Michael; Hazen, Terry C.; Conmy, Robyn; Santo Domingo, Jorge W.

    2017-01-01

    To better understand the impacts of Corexit 9500 on the structure and activity levels of hydrocarbon-degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at 5 and 25°C using both DNA and RNA extracts as the sequencing templates. Oil biodegradation patterns in both 5 and 25°C enrichments were consistent with those reported in the literature (i.e., aliphatics were degraded faster than aromatics). Slight increases in bio...

  6. Chemical weathering and loess inputs to soils in New Zealand's Wairarapa region

    Science.gov (United States)

    Lukens, C. E.; Norton, K. P.

    2017-12-01

    Geochemical mass-balance approaches are commonly used in soils to evaluate patterns in chemical weathering. In conjuction with cosmogenic nuclide measurements of total denudation or soil production, mass-balance approaches have been used to constrain rates of chemical weathering across a variety of landscapes. Here we present geochemical data from a series of soil pits in the Wairarapa region of New Zealand's North Island, where rates of soil production equal rates of total denudation measured using 10Be at sites nearby (i.e., the landscape is in steady state). Soil density increases with depth, consistent with steady weathering over the average soil residence time. However, soil geochemistry indicates very little chemical weathering has occurred, and immobile elements (Zr, Ti, and V) are depleted in soils relative to bedrock. This is contrary to the expected observation, wherein immobile elements should be enriched in soils relative to parent bedrock as weathered mobile solutes are progressively removed from soil. Our geochemical measurements suggest contributions from an exernal source, which has a different chemical composition than the underlying bedrock. We hypothesize that loess constitutes a substantial influx of additional material, and use a mixing model to predict geochemical patterns within soil columns. We evaluate the relative contributions of several likely loess sources, including tephra from the nearby Taupo Volcanic Center, local loess deposits formed during glacial-interglacial transitions, and far-travelling Australian dust. Using an established mass-balance approach with multiple immobile elements, we calculate the fraction of mass in soils contributed by loess to be as much as 25%. Combined with 10Be-derived estimates of soil production, we calculate average loess fluxes up to 320 t/km2/yr, which are consistent with previous estimates of loess acculumation over the late Holocene. Accounting for loess input, we find that chemical weathering

  7. History of enrichment research at the CEA

    International Nuclear Information System (INIS)

    Camarcat, N.

    1996-01-01

    French researches about uranium enrichment have been carried out at the CEA for about 40 years. In the beginning, these researches were considered as marginal and were carried out by a small team from the Powders Central Laboratory. They became intensive since 1955 and culminated in 1967 with the conception of Pierrelatte's factory. Several processes were studied: the gaseous diffusion, the chemical treatments, the centrifugation, the laser and electromagnetic separation processes on atomic and molecular vapors. Only a few of them were fully developed. This paper summarizes the development of these different processes in their historical context. (J.S.). 1 fig

  8. Radiometric enrichment of nonradioactive ores

    International Nuclear Information System (INIS)

    Mokrousov, V.A.; Lileev, V.A.

    1979-01-01

    Considered are the methods of mineral enrichment based on the use of the radioation of various types. The physical essence of enrichment processes is presented, their classification is given. Described are the ore properties influencing the efficiency of radiometric enrichment, methods of the properties study and estimation of ore enrichment. New possibilities opened by radiometric enrichment in the technology of primary processing of mineral raw materials are elucidated. A considerable attention is paid to the main and auxiliary equipment for radiometric enrichment. The foundations of the safety engineering are presented in a brief form. Presented are also results of investigations and practical works in the field of enrichment of ores of non-ferrous, ferrous and non-metallic minerals with the help of radiometric methods

  9. Patterns and sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in surficial sediments of Lakes Erie and Ontario

    International Nuclear Information System (INIS)

    Shen Li; Gewurtz, Sarah B.; Reiner, Eric J.; MacPherson, Karen A.; Kolic, Terry M.; Helm, Paul A.; Brindle, Ian D.; Marvin, Chris H.

    2008-01-01

    This study determines spatial trends and congener patterns of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surficial sediments of Lakes Erie and Ontario. Sediments are enriched in 2378-PCDFs in Lake Ontario, and the PCDD/F concentrations increased from shallow near-shore sediments towards deep-water depositional zone sediments. In Lake Erie, sediments were dominated by octachlorodibenzo-p-dioxin, and the highest PCDD/F concentrations were observed in the western basin and the southern shoreline of the central basin with a decrease towards the eastern basin and the northern shoreline of the central basin. Principal components analysis revealed that chemical manufacture and disposal of chemical waste along the Niagara River has been a major PCDD/F source to Lake Ontario; while PCDD/Fs in Lake Erie are from multiple sources including industrial sources along the Detroit River, major tributaries along the southern shoreline of the lake, and atmospherically-derived material from the upper lakes and connecting channels. - Lake-wide 2378-PCDD/F congener patterns are first reported in L. Erie and L. Ontario sediments

  10. PWR fuel of high enrichment with erbia and enriched gadolinia

    International Nuclear Information System (INIS)

    Bejmer, Klaes-Håkan; Malm, Christian

    2011-01-01

    Today standard PWR fuel is licensed for operation up to 65-70 MWd/kgU, which in most cases corresponds to an enrichment of more than 5 w/o "2"3"5U. Due to criticality safety reason of storage and transportation, only fuel up to 5 w/o "2"3"5U enrichment is so far used. New fuel storage installations and transportation casks are necessary investments before the reactivity level of the fresh fuel can be significantly increased. These investments and corresponding licensing work takes time, and in the meantime a solution that requires burnable poisons in all pellets of the fresh high-enriched fuel might be used. By using very small amounts of burnable absorber in every pellet the initial reactivity can be reduced to today's levels. This study presents core calculations with fuel assemblies enriched to almost 6 w/o "2"3"5U mixed with a small amount of erbia. Some of the assemblies also contain gadolinia. The results are compared to a reference case containing assemblies with 4.95 w/o "2"3"5U without erbia, utilizing only gadolinia as burnable poison. The comparison shows that the number of fresh fuel assemblies can be reduced by 21% (which increases the batch burnup by 24%) by utilizing the erbia fuel concept. However, increased cost of uranium due to higher enrichment is not fully compensated for by the cost gain due to the reduction of the number assemblies. Hence, the fuel cycle cost becomes slightly higher for the high enrichment erbia case than for the reference case. (author)

  11. 77 FR 14838 - General Electric-Hitachi Global Laser Enrichment LLC, Commercial Laser-Based Uranium Enrichment...

    Science.gov (United States)

    2012-03-13

    ... Laser Enrichment LLC, Commercial Laser-Based Uranium Enrichment Facility, Wilmington, North Carolina... a license to General Electric-Hitachi Global Laser Enrichment LLC (GLE or the applicant) to authorize construction of a laser-based uranium enrichment facility and possession and use of byproduct...

  12. THE CHEMICAL EVOLUTION OF THE MONOCEROS RING/GALACTIC ANTICENTER STELLAR STRUCTURE

    International Nuclear Information System (INIS)

    Chou Meiyin; Majewski, Steven R.; Patterson, Richard J.; Cunha, Katia; Smith, Verne V.; MartInez-Delgado, David

    2010-01-01

    The origin of the Galactic Anticenter Stellar Structure (GASS) or 'Monoceros Ring' - a low-latitude overdensity at the edge of the Galactic disk spanning at least the second and third Galactic quadrants-remains controversial. Models for the origin of GASS generally fall into scenarios where either it is a part (e.g., warp) of the Galactic disk or it represents tidal debris from the disruption of a Milky Way (MW) satellite galaxy. To further constrain models for the origin of GASS, we derive chemical abundance patterns from high-resolution spectra for 21 M giants spatially and kinematically identified with it. The abundances of the (mostly) α-element, titanium, and s-process elements, yttrium and lanthanum, for these GASS stars are found to be lower at the same [Fe/H] than those for MW stars, but similar to those of stars in the Sagittarius stream, other dwarf spheroidal galaxies, and the Large Magellanic Cloud. This demonstrates that GASS stars have a chemical enrichment history typical of dwarf galaxies-and unlike those of typical MW stars (at least MW stars near the Sun). Nevertheless, these abundance results cannot definitively rule out the possibility that GASS was dynamically created out of a previously formed, outer MW disk because ΛCDM-based structure formation models show that galactic disks grow outward by accretion of dwarf galaxies. On the other hand, the chemical patterns seen in GASS stars do provide striking verification that accretion of dwarf galaxies has indeed happened at the edge of the MW disk.

  13. Chemical Enrichment of the Solar System by Stellar Ejecta

    Science.gov (United States)

    Kwok, Sun

    2015-03-01

    Spectroscopic observations of evolved stars have shown signatures of aromatic and aliphatic compounds. This suggests that complex organics with chemical structures similar to those of insoluble organic matter (IOM) found in carbonaceous meteorites are made in stars. This raises the possibility that in addition to known pre-solar grains such as silicon carbide, organic star dust may also have traveled across the Galaxy to the Solar System.

  14. Fluorine nuclear magnetic resonance study of enrichment effects in gaseous, liquid and solid uranium hexafluoride

    International Nuclear Information System (INIS)

    Ursu, I.; Demco, D.E.; Simplaceanu, V.; Valcu, N.

    1977-01-01

    The nuclear magnetic resonance method is able to provide information concerning the isotopic content of 235 U in UF 6 by means of measuring the nuclear magnetic transverse relaxation time (T,L2) of 19 F nuclei in liquid UF 6 . In this work, the sources of errors in the T 2 measurements have been analysed and methods for reducing them are dicussed. Typical errors in T 2 determinations are below 2%. The enrichment estimations made by using the linear calibration curves had a deviation of less than 2% with some exceptions. It was found that the chemical impurities may significantly affect the enrichment estimations. 19 F NMR spectra of liquid and gaseous UF 6 at low pressures did not reveal any structure or enrichment effect. The longitudinal nuclear magnetic relaxation of 19 F nuclei in low pressure, gaseous and solid UF 6 showed no enrichment dependence, nor the dipolar relaxation time in solid UF 6 did. (author)

  15. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Gietzen, A.

    1993-01-01

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with General Atomic's standard commercial warranty

  16. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Gietzen, A.

    1993-01-01

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium-zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched-uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with GA's standard commercial warranty

  17. Visual Querying in Chemical Databases using SMARTS Patterns

    OpenAIRE

    Šípek, Vojtěch

    2014-01-01

    The purpose of this thesis is to create framework for visual querying in chemical databases which will be implemented as a web application. By using graphical editor, which is a part of client side, the user creates queries which are translated into chemical query language SMARTS. This query is parsed on the application server which is connected to the chemical database. This framework also contains tooling for creating the database and index structure above it. 1

  18. Turkey's regulatory plans for high enriched to low enriched conversion of TR-2 reactor core

    International Nuclear Information System (INIS)

    Guelol Oezdere, Oya

    2003-01-01

    Turkey is a developing country and has three nuclear facilities two of which are research reactors and one pilot fuel production plant. One of the two research reactors is TR-2 which is located in Cekmece site in Istanbul. TR-2 Reactor's core is composed of both high enriched and low enriched fuel and from high enriched to low enriched core conversion project will take place in year 2005. This paper presents the plans for drafting regulations on the safety analysis report updates for high enriched to low enriched core conversion of TR-2 reactor, the present regulatory structure of Turkey and licensing activities of nuclear facilities. (author)

  19. High enrichment to low enrichment core's conversion. Technical securities

    International Nuclear Information System (INIS)

    Abbate, P.; Madariaga, M.R.

    1990-01-01

    This work presents the fulfillment of the technical securities subscribed by INVAP S.E. for the conversion of a high enriched uranium core. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. These are neutronic and thermohydraulic securities. (Author) [es

  20. Beta activity of enriched uranium

    International Nuclear Information System (INIS)

    Nambiar, P.P.V.J.; Ramachandran, V.

    1975-01-01

    Use of enriched uranium as reactor fuel necessitates its handling in various forms. For purposes of planning and organising radiation protection measures in enriched uranium handling facilities, it is necessary to have a basic knowledge of the radiation status of enriched uranium systems. The theoretical variations in beta activity and energy with U 235 enrichment are presented. Depletion is considered separately. Beta activity build up is also studied for two specific enrichments, in respect of which experimental values for specific alpha activity are available. (author)

  1. Gasket for uranium enrichment plant

    Energy Technology Data Exchange (ETDEWEB)

    Kishi, S; Aiyoshi, H

    1977-02-08

    A gasket to be inserted between flange joints in the equipments and pipe lines of an uranium enrichment plant having neither permeability nor adsorptivity to water while maintaining mechanical, physical and chemical properties of an elastomer gasket is described. A gasket made of an elastomeric material such as a polymer is integratedly formed at its surface with anti-slip projections. The gasket is further surrounded at its upper and lower peripheral sides, as well as outer circumferential portion with a U-sectioned cover (enclosure) made of fluoro-plastics. In this arrangement, the gasket main body shows a gas-tightness for uranium hexafluoride gas and the cover exhibits a gas-tightness for other component gases such as moisture to thereby prevent degradation of the gasket due to absorption and permeation of the moisture.

  2. Ecosystem differences in the trophic enrichment of 13C in aquatic food webs

    International Nuclear Information System (INIS)

    France, R.L.; Peters, R.H.

    1997-01-01

    Data from 35 published studies were collated to examine patterns in the trophic enrichment of 13 C of consumers. Because both δ 13 C and δ 14 N vary systematically across ecosystems, it was necessary to standardize for such differences before combining data from numerous sources. Relationships of these measures of ecosystem-standardized δ 13 C to ecosystem-standardized trophic position (Δδ 15 N) for freshwater, estuarine, coastal, and open-ocean and for all aquatic ecosystems yielded regression equations of low predictive capability (average of 20% explained variance in δ 13 C). However, differences were observed in the slopes between δ 13 C and standardized trophic position when data were examined study-specifically: the average trophic fractionation of 13 C was found to increase from +0.2micron for freshwater to +0.5micron for estuarine to +0.8micron for coastal, and to +1.1micron for open-ocean food webs. This ecosystem-specific gradient in 13 C enrichment for consumers supports previous findings of a similar continuum existing for zooplankton - particulate organic matter differences in δ 13 C. Possible mechanisms to explain these ecosystem-specific patterns in 13 C enrichment may be related to the relative importance of detritus, heterotrophic respiration, partial reliance on alternative food sources, and lipid influences in the different ecosystems. (author)

  3. Isotope enrichment

    International Nuclear Information System (INIS)

    Garbuny, M.

    1979-01-01

    The invention discloses a method for deriving, from a starting material including an element having a plurality of isotopes, derived material enriched in one isotope of the element. The starting material is deposited on a substrate at less than a critical submonatomic surface density, typically less than 10 16 atoms per square centimeter. The deposit is then selectively irradiated by a laser (maser or electronic oscillator) beam with monochromatic coherent radiation resonant with the one isotope causing the material including the one istope to escape from the substrate. The escaping enriched material is then collected. Where the element has two isotopes, one of which is to be collected, the deposit may be irradiated with radiation resonant with the other isotope and the residual material enriched in the one isotope may be evaporated from the substrate and collected

  4. Laser and gas centrifuge enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Heinonen, Olli [Senior Fellow, Belfer Center for Science and International Affairs, Harvard Kennedy School, Cambridge, Massachusetts (United States)

    2014-05-09

    Principles of uranium isotope enrichment using various laser and gas centrifuge techniques are briefly discussed. Examples on production of high enriched uranium are given. Concerns regarding the possibility of using low end technologies to produce weapons grade uranium are explained. Based on current assessments commercial enrichment services are able to cover the global needs of enriched uranium in the foreseeable future.

  5. Enrichment technology. Dependable vendor of gas centrifuges; Enrichment Technology. Zuverlaessiger Lieferant von Gaszentrifugen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2011-10-15

    Enrichment Technology is an innovative, high-tech company that develops, manufactures and installs gas centrifuges for enriching uranium. In addition, Enrichment Technology designs enrichment plants that use gas centrifuge technology. This technology offers the most efficient and cost-effective method for enriching uranium yet: high-performance, safe technology that dominates the market with a global share of 45 percent. A determining factor in Enrichment Technology's success is its mission: supplying its customers with safe, reliable technology. Production of the centrifuges requires versatile know-how and collaboration between different departments as well as interdisciplinary teams at the various sites. More than 2000 operators at 8 sites in 5 countries contribute their individual knowledge and personal skills in order to produce this exceptional technology. The head office is in Beaconsfield near London and the operational headquarters are in Almelo in the Netherlands. There are other sites in Germany (Juelich und Gronau), Great Britain (Capenhurst) as well as project sites in the USA and France. Capenhurst is where experienced engineers design new enrichment plants and organise their construction. Centrifuge components are manufactured in Almelo and Juelich, while the pipework needed to connect up the centrifuges is produced at the site in Gronau. In Juelich, highly qualified scientists in interdisciplinary teams are continuously researching ways of improving the current centrifuges. Communication between specialists in the fields of chemistry, physics and engineering forms the basis for the company's success and the key to extending this leading position in the global enrichment market. (orig.)

  6. Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg.sup.196 enrichment

    Science.gov (United States)

    Grossman, Mark W.

    1993-01-01

    The present invention is directed to a method of eliminating the cold spot zones presently used on Hg.sup.196 isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

  7. Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg[sup 196] enrichment

    Science.gov (United States)

    Grossman, M.W.

    1993-02-16

    The present invention is directed to a method of eliminating the cold spot zones presently used on Hg[sup 196] isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

  8. 76 FR 11523 - Atomic Safety and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility...

    Science.gov (United States)

    2011-03-02

    ... and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility); Notice of... Governmental Entities Regarding Environmental Portion of Enrichment Facility Licensing Proceeding February 24.... White. In this 10 CFR part 70 proceeding regarding the request of applicant AREVA Enrichment Services...

  9. 76 FR 34103 - In the Matter of Areva Enrichment Services, LLC (Eagle Rock Enrichment Facility); Notice of...

    Science.gov (United States)

    2011-06-10

    .... 10-899-02-ML-BD01] In the Matter of Areva Enrichment Services, LLC (Eagle Rock Enrichment Facility...'' portion of this proceeding regarding the December 2008 application by AREVA Enrichment Services, LLC (AES... gas centrifuge uranium enrichment facility--denoted as the Eagle Rock Enrichment Facility (EREF)--in...

  10. Enrichment plants. A survey of major new uranium enriching projects

    International Nuclear Information System (INIS)

    Kovan, D.

    1976-01-01

    The work enrichment situation is reported. The development of enrichment in the U.S. and in Europe is outlined. A brief description is given of the technology of separation by diffusion and by centrifugation and the advantages and disadvantages of the two processes are compared. Finally the supply and demand situation is briefly considered. (U.K.)

  11. Pattern of Morbidity and Mortality in Kurdistan / Iraq with an Emphasis on Exposure to Chemical Weapon

    International Nuclear Information System (INIS)

    Dizaye, K.; Jaff, H.

    2007-01-01

    A cross-sectional survey was carried out in kurdistan -Iraq during the period 2000-2001 to determine patterns of morbidity and mortality among kurdistan population with special emphasis on those exposed to bombs and shell injuries and chemical weapons. Kurdistan was divided in to 300 sectors; from each sector, one household was selected randomly. The total study samples were 6805 including number of the household who have died since 1935. They have a male: female ratio of 1.03:1. An interview was carried out using a special questionnaire form. The mean age of the sample was 51.5 ± 0.6 years (51.1 ± 0.75 for males and 52.9 ± 0.97 for females ) 1.5% and 2.8% of surveyed population have been exposed to non - chemical weapons (bomb and shells ) or chemical weapons , respectively; 0.23% of the alive population had cancer at the time of the study. 12.6% in the study sample were complaining from respiratory disease and 6.5 had a history of miscarriage and stillbirth. Both complaints might be attributed to expose to chemical weapons. 869 (12.5 %) of the study have died since 1935, 68.4% of them have died during the period 1980 - 1999. 3 % of all deaths were due to exposure to shells or chemical weapons; 7.9 % were lost in Al - anfal campaign in 1980s of the last century. 8.5 % of all death were due to cancer probably due to exposure to chemical weapons. (author)

  12. EXTERNAL PHOTOEVAPORATION OF THE SOLAR NEBULA: JUPITER's NOBLE GAS ENRICHMENTS

    International Nuclear Information System (INIS)

    Monga, Nikhil; Desch, Steven

    2015-01-01

    We present a model explaining the elemental enrichments in Jupiter's atmosphere, particularly the noble gases Ar, Kr, and Xe. While He, Ne, and O are depleted, seven other elements show similar enrichments (∼3 times solar, relative to H). Being volatile, Ar is difficult to fractionate from H 2 . We argue that external photoevaporation by far-ultraviolet (FUV) radiation from nearby massive stars removed H 2 , He, and Ne from the solar nebula, but Ar and other species were retained because photoevaporation occurred at large heliocentric distances where temperatures were cold enough (≲ 30 K) to trap them in amorphous water ice. As the solar nebula lost H, it became relatively and uniformly enriched in other species. Our model improves on the similar model of Guillot and Hueso. We recognize that cold temperatures alone do not trap volatiles; continuous water vapor production is also necessary. We demonstrate that FUV fluxes that photoevaporated the disk generated sufficient water vapor in regions ≲ 30 K to trap gas-phase species in amorphous water ice in solar proportions. We find more efficient chemical fractionation in the outer disk: whereas the model of Guillot and Hueso predicts a factor of three enrichment when only <2% of the disk mass remains, we find the same enrichments when 30% of the disk mass remains. Finally, we predict the presence of ∼0.1 M ⊕ of water vapor in the outer solar nebula and protoplanetary disks in H II regions

  13. Developments in uranium enrichment

    International Nuclear Information System (INIS)

    Mohrhauer, H.

    1995-01-01

    The enrichment services market is still characterized by overcapacities. While consumption worldwide will rise by some 15% to 39,000 t SWU/a over the next ten years, capacities amount to nearly 50,000 t SWU/a. The price for enrichment services probably has reached its all time low. Prices below U.S. $ 100/kg SWU are not likely to cover costs even of the economically most advanced enrichment processes. Urenco has prepared for the difficult enrichment business in the years to come by streamlining and cost cutting measures. The company intends to hold and increase its share of more than 10% in the world market. The uranium enrichment plant of Gronau will be expanded further. Expansion beyond 1000 t is subject to another permit being granted under the Atomic Energy Act, an application for which was filed in December 1994. Centrifuge technology is the superior enrichment technology, i.e., there is still considerable potential for further development. Construction of enrichment plants employing the centrifuge technology in the United States and in France is being pursued in various phases, from feasibility studies to licensing procedures. Before these plants could be implemented, however, considerable problems of organization would have to be solved, and the market would have to change greatly, respectively. The laser process, at the present time, does not seem to be able to develop into a major industrial competitor. (orig.) [de

  14. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Gagne, R.W.; Thomas, D.C.

    1977-01-01

    The status of existing uranium enrichment contracts in the US is reviewed and expected natural uranium requirements for existing domestic uranium enrichment contracts are evaluated. Uncertainty in natural uranium requirements associated with requirements-type and fixed-commitment type contracts is discussed along with implementation of variable tails assay

  15. Complex temporal and spatial patterns in nonequilibrium processes

    International Nuclear Information System (INIS)

    1992-01-01

    Dynamical systems methods have been used to study bifurcations and pattern formation in nonequilibrium systems. Accomplishments during this period include: information-theoretic methods for analyzing chaos, chemical reactors for studying sustained reaction-diffusion patterns, a reactor exploiting pattern formation to extract short- lived intermediate species, observation of bifurcation from periodic to quasiperiodic rotating chemical spiral patterns, observation of a Turing bifurcation (transition from uniform state to a stationary chemical pattern), method for extracting noise strength in ramped convection, self-similar fractal structure of Zn clusters in electrodeposition, and dynamical instability in crack propagation

  16. Centrifuge enrichment program

    International Nuclear Information System (INIS)

    Astley, E.R.

    1976-01-01

    Exxon Nuclear has been active in privately funded research and development of centrifuge enrichment technology since 1972. In October of 1975, Exxon Nuclear submitted a proposal to design, construct, and operate a 3000-MT SWU/yr centrifuge enrichment plant, under the provisions of the proposed Nuclear Fuel Assurance Act of 1975. The U.S. Energy Research and Development Administration (ERDA) accepted the proposal as a basis for negotiation. It was proposed to build a 1000-MT SWU/yr demonstration increment to be operational in 1982; and after successful operation for about one year, expand the facilities into a 3000-MT SWU/yr plant. As part of the overall centrifuge enrichment plant, a dedicated centrifuge manufacturing plant would be constructed; sized to support the full 3000-MT SWU/yr plant. The selection of the centrifuge process by Exxon Nuclear was based on an extremely thorough evaluation of current and projected enrichment technology; results show that the technology is mature and the process will be cost effective. The substantial savings in energy (about 93%) from utilization of the centrifuge option rather than gaseous diffusion is a compelling argument. As part of this program, Exxon Nuclear has a large hardware R and D program, plus a prototype centrifuge manufacturing capability in Malta, New York. To provide a full-scale machine and limited cascade test capability, Exxon Nuclear is constructing a $4,000,000 Centrifuge Test Facility in Richland, Washington. This facility was to initiate operations in the Fall of 1976. Exxon Nuclear is convinced that the centrifuge enrichment process is the rational selection for emergence of a commercial enrichment industry

  17. The population of planetary nebulae near the Galactic Centre: chemical abundances

    Science.gov (United States)

    Mollá, M.; Cavichia, O.; Costa, R. D. D.; Maciel, W. J.

    2017-10-01

    In this work, we report physical parameters and abundances derived for a sample of 15 high extinction planetary nebulae located in the inner 2° of the Galactic bulge, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman spectrograph. The new data allow us to extend our database including older, weaker objects that are at the faint end of the planetary nebulae luminosity function. The data provide chemical compositions for PNe located in this region of the bulge to explore the chemical enrichment history of the central region of the Galactic bulge. The results show that the abundances of our sample are skewed to higher metallicities than previous data in the outer regions of the bulge. This can indicate a faster chemical enrichment taking place at the Galactic centre.

  18. Modeling study of vibrational photochemical isotope enrichment. [HBr + Cl/sub 2/; HCl + Br/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Badcock, C.C.; Hwang, W.C.; Kalsch, J.F.

    1978-09-29

    Chemical kinetic modeling studies of vibrational-photochemical isotope enrichment have been performed on two systems: Model (I), H/sup 79/Br(H/sup 81/Br) + Cl/sub 2/ and, Model (II), H/sup 37/Cl(H/sup 35/Cl) + Br. Pulsed laser excitation was modeled to the first excited vibrational level of H/sup 79/Br in Model I and the first and second excited vibrational levels of both HCl isotopes in Model II. These are prototype systems of exoergic (Model I) and endoergic (Model II) reactions. The effects on enrichment of varying the external parameters (pressure, laser intensity) and the internal parameters (rate constants for V-V exchange and excited-state reactions) were examined. Studies of these prototype systems indicate that a favorable reaction for enrichment, with isotopically-specific excitation and a significantly accelerated vibrationally-excited-state reaction should have the following properties: the reaction from v = 0 should be only moderately exoergic, and the most favorable coreactant should be a polyatomic species, such as alkyl radical. Direct excitation of the reacting vibrational level is at least an order of magnitude more favorable for enrichment than is population by energy transfer. Enrichment of the minor isotope by these processes is more effective than is major isotope enrichment. Within limits, increased laser intensity is beneficial. However, for sequential excitation of a second vibrational level, major isotope enrichment can be diminished by high populations of the first vibrational level.

  19. Studies of MHD generator performance with oxygen enriched coal combustion

    Science.gov (United States)

    Wormhoudt, J.; Yousefian, V.; Kolb, C. E.; Martinez-Sanchez, M.

    1980-07-01

    This paper presents calculations made using the Aerodyne PACKAGE (Plasma Analysis, Chemical Kinetics, and Generator Efficiency) computer code which bear on two questions which arise in connection with choices between oxygen enrichment and air preheating to attain the high combustion temperatures needed for open-cycle, coal-fired MHD power generation. The first question is which method produces the highest enthalpy extraction per unit channel length. The second is, in test facilities intended to study tradeoffs between oxygen enrichment and preheated air, can good generator performance be obtained from the same physical channel for different combustor compositions. The answer to the first question is found to depend on what combustor conditions are taken to be comparable. As for the second question, it is found that operation with channel input from off-design combustor conditions can cause serious problems, which can be partially alleviated by changing the channel load factors.

  20. Candidate processes for diluting the 235U isotope in weapons-capable highly enriched uranium

    International Nuclear Information System (INIS)

    Snider, J.D.

    1996-02-01

    The United States Department of Energy (DOE) is evaluating options for rendering its surplus inventories of highly enriched uranium (HEU) incapable of being used to produce nuclear weapons. Weapons-capable HEU was earlier produced by enriching uranium in the fissile 235 U isotope from its natural occurring 0.71 percent isotopic concentration to at least 20 percent isotopic concentration. Now, by diluting its concentration of the fissile 235 U isotope in a uranium blending process, the weapons capability of HEU can be eliminated in a manner that is reversible only through isotope enrichment, and therefore, highly resistant to proliferation. To the extent that can be economically and technically justified, the down-blended uranium product will be made suitable for use as commercial reactor fuel. Such down-blended uranium product can also be disposed of as waste if chemical or isotopic impurities preclude its use as reactor fuel

  1. A Systematic Approach to Marital Enrichment.

    Science.gov (United States)

    Dinkmeyer, Don; Carlson, Jon

    1986-01-01

    Presents a systematic approach to enriching marital relationships. The history and current status of marital enrichment is reviewed. An Adlerian approach to marital enrichment is described. Applications of the program in enrichment groups, marriage therapy and couple groups are included. (Author)

  2. Cell patterning on poly(sodium 4-styrenesulfonate)-patterned fluoropolymer substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wan-Joong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Department of Polymer Science and Engineering, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Jung, Chang-Hee; Hwang, In-Tae [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Jung, Chan-Hee, E-mail: jch@kaeri.re.kr [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Choi, Jae-Hak, E-mail: jaehakchoi@cnu.ac.kr [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Department of Polymer Science and Engineering, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Hong, Sung-Kwon [Department of Polymer Science and Engineering, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2013-10-15

    Highlights: •PFA films were functionalized by ion-beam induced surface graft polymerization. •Poly(sodium 4-styrenesulfonate) (PSS)-patterned PFA films were prepared. •Well-organized cell patterns were obtained on PSS-patterned PFA films. •This method is useful to fabricate bio-platforms for cell-based biodevices. -- Abstract: The surface functionalization of bio-inert fluoropolymer films through ion beam-induced surface graft polymerization was investigated to control the cellular behavior. The surface of poly(tetrafluoroethylene-co-perfluoropropl vinyl ether) (PFA) films was selectively activated by 150 keV H{sup +} ion implantation in the presence of a pattern mask and sodium 4-styrenesulfonate (SS) was then graft polymerized onto the implanted PFA films to form hydrophilic poly(sodium 4-styrenesulfonate) (PSS)-patterned PFA films. The surface of the resulting PSS-patterned PFA films was investigated in terms of the degree of graft polymerization, chemical structure, chemical composition, wettability, and morphology. The analytical results revealed that PSS was selectively grafted onto the implanted regions of the PFA films. Furthermore, in vitro cell culture on the PSS-patterned PFA films exhibited a preferential adhesion and growth of cells onto the PSS-grafted regions, resulting in well-organized 100 μm cell patterns.

  3. Cell patterning on poly(sodium 4-styrenesulfonate)-patterned fluoropolymer substrate

    International Nuclear Information System (INIS)

    Kim, Wan-Joong; Jung, Chang-Hee; Hwang, In-Tae; Jung, Chan-Hee; Choi, Jae-Hak; Hong, Sung-Kwon

    2013-01-01

    Highlights: •PFA films were functionalized by ion-beam induced surface graft polymerization. •Poly(sodium 4-styrenesulfonate) (PSS)-patterned PFA films were prepared. •Well-organized cell patterns were obtained on PSS-patterned PFA films. •This method is useful to fabricate bio-platforms for cell-based biodevices. -- Abstract: The surface functionalization of bio-inert fluoropolymer films through ion beam-induced surface graft polymerization was investigated to control the cellular behavior. The surface of poly(tetrafluoroethylene-co-perfluoropropl vinyl ether) (PFA) films was selectively activated by 150 keV H + ion implantation in the presence of a pattern mask and sodium 4-styrenesulfonate (SS) was then graft polymerized onto the implanted PFA films to form hydrophilic poly(sodium 4-styrenesulfonate) (PSS)-patterned PFA films. The surface of the resulting PSS-patterned PFA films was investigated in terms of the degree of graft polymerization, chemical structure, chemical composition, wettability, and morphology. The analytical results revealed that PSS was selectively grafted onto the implanted regions of the PFA films. Furthermore, in vitro cell culture on the PSS-patterned PFA films exhibited a preferential adhesion and growth of cells onto the PSS-grafted regions, resulting in well-organized 100 μm cell patterns

  4. All SNPs are not created equal: genome-wide association studies reveal a consistent pattern of enrichment among functionally annotated SNPs

    DEFF Research Database (Denmark)

    Schork, Andrew J; Thompson, Wesley K; Pham, Phillip

    2013-01-01

    Recent results indicate that genome-wide association studies (GWAS) have the potential to explain much of the heritability of common complex phenotypes, but methods are lacking to reliably identify the remaining associated single nucleotide polymorphisms (SNPs). We applied stratified False...... Discovery Rate (sFDR) methods to leverage genic enrichment in GWAS summary statistics data to uncover new loci likely to replicate in independent samples. Specifically, we use linkage disequilibrium-weighted annotations for each SNP in combination with nominal p-values to estimate the True Discovery Rate...... in introns, and negative enrichment for intergenic SNPs. Stratified enrichment directly leads to increased TDR for a given p-value, mirrored by increased replication rates in independent samples. We show this in independent Crohn's disease GWAS, where we find a hundredfold variation in replication rate...

  5. 77 FR 13367 - General Electric-Hitachi Global Laser Enrichment, LLC, Proposed Laser-Based Uranium Enrichment...

    Science.gov (United States)

    2012-03-06

    ... NUCLEAR REGULATORY COMMISSION [NRC-2009-0157] General Electric-Hitachi Global Laser Enrichment, LLC, Proposed Laser-Based Uranium Enrichment Facility, Wilmington, NC AGENCY: Nuclear Regulatory... Impact Statement (EIS) for the proposed General Electric- Hitachi Global Laser Enrichment, LLC (GLE...

  6. The enrichment secondary market

    International Nuclear Information System (INIS)

    Einbund, D.R.

    1986-01-01

    This paper will addresses two topics: the background to the present status of the enrichment secondary market and the future outlook of the secondary market in enrichment services, and the viability of the nuclear fuel brokerage industry. These two topics are inevitably connected, as most secondary market activity, not only in enrichment but also in natural uranium, has traditionally been conducted with the participation of brokers. Therefore, the author interrelates these topics

  7. Thermal breeder fuel enrichment zoning

    International Nuclear Information System (INIS)

    Capossela, H.J.; Dwyer, J.R.; Luce, R.G.; McCoy, D.F.; Merriman, F.C.

    1992-01-01

    A method and apparatus for improving the performance of a thermal breeder reactor having regions of higher than average moderator concentration are disclosed. The fuel modules of the reactor core contain at least two different types of fuel elements, a high enrichment fuel element and a low enrichment fuel element. The two types of fuel elements are arranged in the fuel module with the low enrichment fuel elements located between the high moderator regions and the high enrichment fuel elements. Preferably, shim rods made of a fertile material are provided in selective regions for controlling the reactivity of the reactor by movement of the shim rods into and out of the reactor core. The moderation of neutrons adjacent the high enrichment fuel elements is preferably minimized as by reducing the spacing of the high enrichment fuel elements and/or using a moderator having a reduced moderating effect. 1 figure

  8. Uranium enrichment in the United States

    International Nuclear Information System (INIS)

    Hill, J.H.; Parks, J.W.

    1975-01-01

    History, improvement programs, status of electrical power availability, demands for uranium enrichment, operating plan for the U. S. enriching facilities, working inventory of enriched uranium, possible factors affecting deviations in the operating plan, status of gaseous diffusion technology, status of U. S. gas centrifuge advances, transfer of enrichment technology, gaseous diffusion--gas centrifuge comparison, new enrichment capacity, U. S. separative work pricing, and investment in nuclear energy are discussed. (LK)

  9. Natural uranium utilization without enrichment and reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, H.; Toshinsky, V.; Ryu, K. [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

    2001-07-01

    Two types of fast reactor are investigated to utilize the natural uranium without enrichment and reprocessing in an equilibrium state. The first trial is SFPR. Its fuel-shuffling pattern is optimized. An obtained result gives its peak fuel burnup of 22,5%, power peaking factor of 1.5 and peak excess reactivity of 2,15%. The second trial is CANDLE burnup scheme, where distribution shapes of neutron flux and nuclide densities are constant but move in axial direction with a constant velocity. A feasible solution gives the speed of burning region of 4,1 cm/year, k{sub eff} of 1,02 and average spent fuel burnup of 41%. (author)

  10. Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

    Directory of Open Access Journals (Sweden)

    Jason D Thompson

    Full Text Available Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

  11. Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

    Science.gov (United States)

    Thompson, Jason D; Shibahara, Gosuke; Rajan, Sweta; Pel, Joel; Marziali, Andre

    2012-01-01

    Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

  12. Enrichment into the 21st century

    International Nuclear Information System (INIS)

    Rutkowski, E.

    1995-01-01

    This article discusses the future of the enrichment services market into the next century. It is estimated that demand for enrichment services will reach 31 million SWU by the end of the century and remain constant for the following 10 years. The current world enrichment capacity is 44 million SWU, or some 50% ahead of the demand. This oversupply is projected to continue into the next century, but in spite of this, several suppliers are planning new enrichment facilities. HEU as a source of enriched uranium is examined. Overall, long-term prices for enrichment services are expected to decline in the coming decade

  13. The commercial role for centrifuge enrichment

    International Nuclear Information System (INIS)

    Readle, P.H.; Wilcox, P.

    1987-01-01

    The enrichment market is extremely competitive and capacity greatly exceeds demand. BNFL [British Nuclear Fuels Ltd.] is in a unique position in having commercial experience of the two enrichment technologies currently used industrially: diffusion, and centrifuge enrichment through its associate company Urenco. In addition, BNFL is developing laser enrichment techniques as part of a UK development programme. The paper describes the enrichment market, briefly discusses the relative merits of the various methods of uranium enrichment and concludes that the gas centrifuge will be best able to respond to market needs for at least the remainder of the century. (author)

  14. High enrichment to low enrichment core's conversion. Accidents analysis

    International Nuclear Information System (INIS)

    Abbate, P.; Rubio, R.; Doval, A.; Lovotti, O.

    1990-01-01

    This work analyzes the different accidents that may occur in the reactor's facility after the 20% high-enriched uranium core's conversion. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. This analysis includes: a) accidents by reactivity insertion; b) accidents by coolant loss; c) analysis by flow loss and d) fission products release. (Author) [es

  15. Microbial biomass, community structure and metal tolerance of a naturally Pb-enriched forest soil.

    Science.gov (United States)

    Bååth, E; Díaz-Raviña, M; Bakken, L R

    2005-11-01

    The effect of long-term elevated soil Pb levels on soil microbiota was studied at a forest site in Norway, where the soil has been severely contaminated with Pb since the last period of glaciation (several thousand years). Up to 10% Pb (total amount, w/w) has been found in the top layer. The microbial community was drastically affected, as judged from changes in the phospholipid fatty acid (PLFA) pattern. Specific PLFAs that were high in Pb-enriched soil were branched (especially br17:0 and br18:0), whereas PLFAs common in eukaryotic organisms such as fungi (18:2omega6,9 and 20:4) were low compared with levels at adjacent, uncontaminated sites. Congruent changes in the PLFA pattern were found upon analyzing the culturable part of the bacterial community. The high Pb concentrations in the soil resulted in increased tolerance to Pb of the bacterial community, measured using both thymidine incorporation and plate counts. Furthermore, changes in tolerance were correlated to changes in the community structure. The bacterial community of the most contaminated soils showed higher specific activity (thymidine and leucine incorporation rates) and higher culturability than that of control soils. Fungal colony forming units (CFUs) were 10 times lower in the most Pb-enriched soils, the species composition was widely different from that in control soils, and the isolated fungi had high Pb tolerance. The most commonly isolated fungus in Pb-enriched soils was Tolypocladium inflatum. Comparison of isolates from Pb-enriched soil and isolates from unpolluted soils showed that T. inflatum was intrinsically Pb-tolerant, and that the prolonged conditions with high Pb had not selected for any increased tolerance.

  16. Advanced Neutron Source enrichment study

    International Nuclear Information System (INIS)

    Bari, R.A.; Ludewig, H.; Weeks, J.R.

    1996-01-01

    A study has been performed of the impact on performance of using low-enriched uranium (20% 235 U) or medium-enriched uranium (35% 235 U) as an alternative fuel for the Advanced Neutron Source, which was initially designed to use uranium enriched to 93% 235 U. Higher fuel densities and larger volume cores were evaluated at the lower enrichments in terms of impact on neutron flux, safety, safeguards, technical feasibility, and cost. The feasibility of fabricating uranium silicide fuel at increasing material density was specifically addressed by a panel of international experts on research reactor fuels. The most viable alternative designs for the reactor at lower enrichments were identified and discussed. Several sensitivity analyses were performed to gain an understanding of the performance of the reactor at parametric values of power, fuel density, core volume, and enrichment that were interpolations between the boundary values imposed on the study or extrapolations from known technology

  17. A Model-Based Analysis of Chemical and Temporal Patterns of Cuticular Hydrocarbons in Male Drosophila melanogaster

    Science.gov (United States)

    Kent, Clement; Azanchi, Reza; Smith, Ben; Chu, Adrienne; Levine, Joel

    2007-01-01

    Drosophila Cuticular Hydrocarbons (CH) influence courtship behaviour, mating, aggregation, oviposition, and resistance to desiccation. We measured levels of 24 different CH compounds of individual male D. melanogaster hourly under a variety of environmental (LD/DD) conditions. Using a model-based analysis of CH variation, we developed an improved normalization method for CH data, and show that CH compounds have reproducible cyclic within-day temporal patterns of expression which differ between LD and DD conditions. Multivariate clustering of expression patterns identified 5 clusters of co-expressed compounds with common chemical characteristics. Turnover rate estimates suggest CH production may be a significant metabolic cost. Male cuticular hydrocarbon expression is a dynamic trait influenced by light and time of day; since abundant hydrocarbons affect male sexual behavior, males may present different pheromonal profiles at different times and under different conditions. PMID:17896002

  18. A model-based analysis of chemical and temporal patterns of cuticular hydrocarbons in male Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Clement Kent

    Full Text Available Drosophila Cuticular Hydrocarbons (CH influence courtship behaviour, mating, aggregation, oviposition, and resistance to desiccation. We measured levels of 24 different CH compounds of individual male D. melanogaster hourly under a variety of environmental (LD/DD conditions. Using a model-based analysis of CH variation, we developed an improved normalization method for CH data, and show that CH compounds have reproducible cyclic within-day temporal patterns of expression which differ between LD and DD conditions. Multivariate clustering of expression patterns identified 5 clusters of co-expressed compounds with common chemical characteristics. Turnover rate estimates suggest CH production may be a significant metabolic cost. Male cuticular hydrocarbon expression is a dynamic trait influenced by light and time of day; since abundant hydrocarbons affect male sexual behavior, males may present different pheromonal profiles at different times and under different conditions.

  19. Prospects and problems of uranium enrichment

    International Nuclear Information System (INIS)

    Imai, Ryukichi

    1974-01-01

    The problem of uranium enrichment now concerns principally peaceful nuclear power generation. With the current oil crisis, energy resources assume unprecedented importance. However, the requirements for enriched uranium vary with the vicissitude of the world situation in nuclear power generation; the enterprise of uranium enrichment is related to economic aspect. The following matters are described: dimension of enrichment problem, political factors, changes in requirements, projects in each country, and strategy of enrichment in Japan. (Mori, K.)

  20. Uranium enrichment: an overview

    International Nuclear Information System (INIS)

    Cazalet, J.

    1995-01-01

    This paper is a general presentation of uranium enrichment processes and assessments of the prevailing commercial and industrial situations. It gives first some theoretical aspects of enrichment in general and explains the differences between statistical and selective processes in particular. Then a review of the different processes is made with a comparison between them. Finally, some general remarks concerning applications are given and the risks of proliferation related to enrichment are mentioned. (J.S.). 4 refs., 5 figs., 8 tabs

  1. Bacterial Community Profiling of H2/CO2 or Formate-Utilizing Acetogens Enriched from Diverse Ecosystems

    Science.gov (United States)

    Han, R.; Zhang, L.; Fu, B.; Liu, H.

    2014-12-01

    Synthetic gases are usually generated from either cellulosic agricultural waste combustion or industrial release and could be subsequently transformed into acetate, ethanol, and/or butyrate by homoacetogenic bacteria, which commonly possess reductive acetyl-CoA synthesis pathway. Homoacetogen-based syngas fermentation technology provides an alternative solution to link greenhouse gas emission control and cellulosic solid waste treatment with biofuels production. The objective of our current project is to hunt for homoacetogens with capabilities of highly efficiently converting syngases to chemical solvents. In this study, we evaluated homoacetogens population dynamics during enrichments and pinpointed dominant homoacetogens representing diverse ecosystems enriched by different substrates. We enriched homoacetogens from four different samples including waste activate sludge, freshwater sediment, anaerobic methanogenic sludge, and cow manure using H2/CO2 (4:1) or formate as substrate for homoacetogen enrichment. Along with the formyltetrahydrofolate synthetase (FTHFS) gene (fhs gene)-specific real time qPCR assay and Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis, 16S rRNA based 454 high-throughput pyrosequencing was applied to reveal the population dynamic and community structure during enrichment from different origins. Enrichment of homoacetogenic populations coincided with accumulations of short chain fatty acids such as acetate and butyrate. 454 high-throughput pyrosequencing revealed Firmicutes and Spirochaetes populations became dominant while the overall microbial diversity decreased after enrichment. The most abundant sequences among the four origins belonged to the following phyla: Firmicutes, Spirochaetes, Proteobacteria, and Bacteroidetes, accounting for 62.1%-99.1% of the total reads. The major putative homoacetogenic species enriched on H2/CO2 or formate belonged to Clostridium spp., Acetobacterium spp., Acetoanaerobium spp

  2. Engineering Enriched Microenvironments with Gradients of Platelet Lysate in Hydrogel Fibers.

    Science.gov (United States)

    Santo, Vítor E; Babo, Pedro; Amador, Miguel; Correia, Cláudia; Cunha, Bárbara; Coutinho, Daniela F; Neves, Nuno M; Mano, João F; Reis, Rui L; Gomes, Manuela E

    2016-06-13

    Gradients of physical and chemical cues are characteristic of specific tissue microenvironments and contribute toward morphogenesis and tissue regeneration upon injury. Recent advances on microfluidics and hydrogel manipulation raised the possibility of generating biomimetic biomaterials enriched with bioactive factors and encapsulating cells following designs specifically tailored for a target application. The novelty of this work relies on the combination of methacrylated gellan gum (MeGG) with platelet lysate (PL), aiming to generate novel advanced 3D PL-enriched photo-cross-linkable hydrogels and overcoming the lack of adhesion sites provided by the native MeGG hydrogels. This combination takes advantage of the availability, enriched growth factor composition, and potential autologous application of PL while simultaneously preserving the ability provided by MeGG to tailor mechanical properties, protein release kinetics, and shape of the construct according to the desired goal. Incorporation of PL in the hydrogels significantly improved cellular adhesion and viability in the constructs. The use of microfluidic tools allowed the design of a fiber-like hydrogel incorporating a gradient of PL along the length of the fiber. These spatial protein gradients led to the viability and cell number gradients caused by maintenance of human umbilical vein endothelial cells (HUVECs) survival in the fibers toward the PL-enriched sections in comparison with the nonloaded MeGG sections of the fibers. Altogether, we propose a proof of concept strategy to design a PL gradient biomaterial with potential in tissue engineering approaches and analysis of cell-microenvironment interactions.

  3. Enrichment Mechanism of Semiconducting Single-walled Carbon Nanotubes by Surfactant Amines

    Science.gov (United States)

    Ju, Sang-Yong; Utz, Marcel; Papadimitrakopoulos, Fotios

    2009-01-01

    Utilization of single-walled carbon nanotubes (SWNTs) in high-end applications hinges on separating metallic (met-) from semiconducting (sem-) SWNTs. Surfactant amines, like octadecylamine (ODA) have proven instrumental for the selective extraction of sem-SWNTs from tetrahydrofuran (THF) nanotube suspensions. The chemical shift differences along the tail of an asymmetric, diacetylenic surfactant amine were used to probe the molecular dynamics in the presence and absence of nanotubes via NMR. The results suggest that the surfactant amine head is firmly immobilized onto the nanotube surface together with acidic water, while the aliphatic tail progressively gains larger mobility as it gets farther from the SWNT. X-ray and high-resolution TEM studies indicate that the sem-enriched sample is populated mainly by small nanotube bundles containing ca. three SWNTs. Molecular simulations in conjunction with previously determined HNO3/H2SO4 oxidation depths for met- and sem-SWNTs indicate that the strong pinning of the amine surfactants on the sem-enriched SWNTs bundles is a result of a well-ordered arrangement of nitrate/amine salts separated with a monomolecular layer of H2O. Such continuous 2D arrangement of nitrate/amine salts shields the local environment adjacent to sem-enriched SWNTs bundles and maintains an acidic pH that preserves nanotube oxidation (i.e. SWNTn+). This, in turn, results in strong interactions with charge-balancing NO3- counter ions that through their association with neutralized surfactant amines provide effective THF dispersion and consequent sem-enrichment. PMID:19397291

  4. Supply of low enriched (LEU) and highly enriched uranium (HEU) for research reactors

    International Nuclear Information System (INIS)

    Mueller, H.

    1997-01-01

    Enriched uranium for research reactors in the form of LEU /= low enriched uranium at 19.75% U-235) and HEU (= highly enriched uranium at 90 to 93% U-235) was and is - due to its high U-235 enrichment - a political fuel other than enriched uranium for power reactors. The sufficient availability of LEU and HEU is a vital question for research reactors, especially in Europe, in order to perform their peaceful research reactor programs. In the past the USA were in the Western hemisphere sole supplier of LEU and HEU. Today the USA have de facto stopped the supply of LEU and HEU, for HEU mainly due to political reasons. This paper deals, among others, with the present availability of LEU and HEU for European research reactors and touches the following topics: - historical US supplies, - influence of the RERTR-program, - characteristics of LEU and HEU, - military HEU enters the civil market, -what is the supply situation for LEU and HEU today? - outlook for safe supplies of LEU and HEU. (author)

  5. Growth of nicotiana in response to atmospheric CO sub 2 enrichment and various light regimes

    Energy Technology Data Exchange (ETDEWEB)

    Pope, S.; Thomas, J.F. (North Carolina State Univ., Raleigh (USA))

    1989-04-01

    Nicotiana tabacum NCTG-22, N. tabacum Petite Havana and N. plumbaginifolia were grown in chambers (24 C, 12-h light) under daytime atmospheric CO{sub 2} levels of 340 ppm (ambient) or 1000 ppm (enriched). All 3 types of tobacco grew faster and had open flowers sooner under CO2 enrichment, but patterns of dry weight distribution varied with type of tobacco. In N. plumbaginifolia significant proportions of dry weight were allocated to stems and branches, while in tabacum types, less was allocated to stems and more to leaves and roots. Increases in dry weight due to CO2 enrichment were accompanied by increases in leaf area and thickness. Plants given a far-red low intensity night break exhibited few differences from controls except having thinner leaves under ambient CO2; but under enriched CO2, had greater total dry weight and thicker leaves containing a higher proportion of spongy mesophyll than controls. A 50% reduction in light intensity led to a comparable reduction in dry weight and leaf area across treatments.

  6. Phylogeny is a powerful tool for predicting plant biomass responses to nitrogen enrichment.

    Science.gov (United States)

    Wooliver, Rachel C; Marion, Zachary H; Peterson, Christopher R; Potts, Brad M; Senior, John K; Bailey, Joseph K; Schweitzer, Jennifer A

    2017-08-01

    -independence, eucalypt responses to N were not associated with functional traits (although post-hoc analyses show a phylogenetic pattern in specific root length similar to that of responses to N), nor were responses differentially limited by P. Overall, our model results suggest that phylogeny is a powerful predictor of winners and losers in anthropogenic N enrichment scenarios in Tasmanian eucalypts, which may have implications for other species. © 2017 by the Ecological Society of America.

  7. Lanthanide-IMAC enrichment of carbohydrates and polyols.

    Science.gov (United States)

    Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

    2014-03-01

    In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes

    Directory of Open Access Journals (Sweden)

    P. Ginot

    2006-01-01

    Full Text Available A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l, 30°08' S, 69°55' W was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Assuming that, like measured during the field campaign, the enrichment of chloride was always related to sublimation, the chemical record along the ice core may be applied to reconstruct the history of such secondary processes linked to the past climatic conditions over northern Chile. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation is related with the Southern Oscillation Index (SOI: higher net-accumulation during El-Niño years and more sublimation during La Niña years. The deepest part of the ice record shows a time discontinuity; with an ice body deposited under different climatic conditions: 290 mm higher precipitation but with reduced seasonal distribution (+470 mm in winter and –180 mm in summer and –3°C lower mean annual temperature. Unfortunately, its age is unknown. The comparison with regional proxy data however let us conclude that the glacier buildup did most likely occur after the dry mid-Holocene.

  9. The competitive enrichment market

    International Nuclear Information System (INIS)

    Parks, J.W.; Huffman, F.C.

    1984-01-01

    With the enactment of the ''Private Ownership of Special Nuclear Materials Act'' in 1964, the U.S. Government made provisions to enter into the uranium enrichment services business. Since nuclear power was in its infancy and the Government was promoting its growth as well as trying to help U.S. industry sell reactors overseas, the initial contracts (Requirements Contracts) for enrichment services placed most of the risks associated with the supplying of the services on the Government. Projections of nuclear power additions continued to grow and in 1972 the Atomic Energy Commission (AEC) stopped contracting under Requirements Contracts in order to study which mode of contracting best suited the commercial development of the industry. In mid-1973, the AEC introduced the Long-Term Fixed Commitment (LTFC) contract which shifted the risk to the customer. By mid-1974, AEC had contracts which completely used the enrichment capacity of its complex and refused to accept requests for additional contracts. This action further convinced European nations that they should continue to develop their own enrichment capacity and resulted in the EURODIF and URENCO projects. Before this time the U.S. supplied 100% of the world market for enriching services

  10. Enrichment: Dealing with overcapacity

    International Nuclear Information System (INIS)

    Peterson, C.H.

    1989-01-01

    Today's surplus of enrichment capacity will continue until at least the end of this century. This will challenge the ingenuity of the separative work unit (SWU) suppliers as they attempt to keep market share and remain profitable in a very competitive marketplace. The utilities will be faced with attractive choices, but making the best choice will require careful analysis and increased attention to market factors. Current demand projections will probably prove too high to the extent that more reactors are canceled or delayed. The DOE has the vast majority of the unused capacity, so it will feel the most immediate impact of this large surplus in productive capacity. The DOE has responded to these market challenges by planning another reorganization of its enriching operations. Without a major agreement among the governments affected by the current surplus in enrichment capacity, the future will see lower prices, more competitive terms, and the gradual substitution of centrifuge or laser enrichment for the gaseous diffusion plants. The competition that is forcing the gaseous diffusion prices down to marginal cost will provide the long-term price basis for the enrichment industry

  11. The Effect of Mangrove Leaf Litter Enrichment on Macrobenthic Colonization of Defaunated Sandy Substrates

    Science.gov (United States)

    Lee, S. Y.

    1999-11-01

    The importance of exported mangrove materials to nearshore macrobenthos has largely been predicted based upon decomposition and utilization studies conducted within the mangrove environment, and from quantitative measurements of export. The present study evaluated the impact of mangrove leaf litter enrichment on non-mangrove substrates in a high-salinity microcosm experiment. Fortnightly addition of Kandelia candel leaf detritus at levels equivalent to 0·66 and 0·33 mg cm -2day -1in defaunated sand in microcosms maintained under high salinity conditions and on a sandy substrate resulted in no significant differences from the control in total faunal dry biomass or ash-free dry weight (AFDW) after 28, 73, 137 and 217 days of experiment. Duration of experiment was significant in determining the biomass (both dry weight and AFDW) of the macrofaunal assemblage in the microcosms, but neither enrichment nor its interaction with time had an effect. Species richness, Shannon diversity and evenness, and the total number of individuals, however, decreased in the order control>low enrichment>high enrichment for almost all sampling dates. By contrast, soluble tannins in the microcosm sediment demonstrated the reverse pattern. Both duration of experiment and enrichment were significant in determining species richness and the total number of individuals. The interaction between time and enrichment level was significant in the former but not the latter case. Discriminant analysis performed on the species abundance data indicated distinct animal assemblages characteristic of the three enrichment levels. These findings suggest that mangrove organic matter may not necessarily result in enhancement effects on marine benthos but high concentrations of tannins may hamper colonization by the macrobenthos.

  12. Development of on-line uranium enrichment monitor of gaseous UF6 for uranium enrichment plant

    International Nuclear Information System (INIS)

    Lu Xuesheng; Liu Guorong; Jin Huimin; Zhao Yonggang; Li Jinghuai; Hao Xueyuan; Ying Bin; Yu Zhaofei

    2013-01-01

    An on-line enrichment monitor was developed to measure the enrichment of UF 6 , flowing through the processing pipes in uranium enrichment plant. A Nal (Tl) detector was used to measure the count rates of the 185.7 keV γ-ray emitted from 235 U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade can be monitored continuously by using the device. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant. (authors)

  13. Oxygen enrichment incineration

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  14. Oxygen enrichment incineration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  15. A route for oxygen isotope enrichment of α-COOH groups in amino acids

    International Nuclear Information System (INIS)

    Steinschneidner, A.; St Armour, T.; Valentine, B.; Burgar, M.I.; Fiat, D.

    1981-01-01

    Oxygen-17 was introduced into leucine, proline, phenylalanine and tyrosine. The corresponding tert-butyloxycarbonyl amino acids were first converted to their O-methyl esters. Following saponification with Na 17 OH, the tert-butyloxycarbonyl group was removed to yield free amino acid enriched with oxygen-17 by approximately 1000-fold. Oxygen-17 NMR revealed well-resolved peaks for the labelled amino acids. The chemical shifts are reported. (author)

  16. SignalSpider: Probabilistic pattern discovery on multiple normalized ChIP-Seq signal profiles

    KAUST Repository

    Wong, Kachun

    2014-09-05

    Motivation: Chromatin immunoprecipitation (ChIP) followed by high-throughput sequencing (ChIP-Seq) measures the genome-wide occupancy of transcription factors in vivo. Different combinations of DNA-binding protein occupancies may result in a gene being expressed in different tissues or at different developmental stages. To fully understand the functions of genes, it is essential to develop probabilistic models on multiple ChIP-Seq profiles to decipher the combinatorial regulatory mechanisms by multiple transcription factors. Results: In this work, we describe a probabilistic model (SignalSpider) to decipher the combinatorial binding events of multiple transcription factors. Comparing with similar existing methods, we found SignalSpider performs better in clustering promoter and enhancer regions. Notably, SignalSpider can learn higher-order combinatorial patterns from multiple ChIP-Seq profiles. We have applied SignalSpider on the normalized ChIP-Seq profiles from the ENCODE consortium and learned model instances. We observed different higher-order enrichment and depletion patterns across sets of proteins. Those clustering patterns are supported by Gene Ontology (GO) enrichment, evolutionary conservation and chromatin interaction enrichment, offering biological insights for further focused studies. We also proposed a specific enrichment map visualization method to reveal the genome-wide transcription factor combinatorial patterns from the models built, which extend our existing fine-scale knowledge on gene regulation to a genome-wide level. Availability and implementation: The matrix-algebra-optimized executables and source codes are available at the authors\\' websites: http://www.cs.toronto.edu/∼wkc/SignalSpider. Contact: Supplementary information: Supplementary data are available at Bioinformatics online.

  17. Low enrichment Mo-99 target development program at ANSTO

    International Nuclear Information System (INIS)

    Donlevy, Therese M.; Anderson, Peter J.; Beattie, David; Braddock, Ben; Fulton, Scott; Godfrey, Robert; Law, Russell; McNiven, Scott; Sirkka, Pertti; Storr, Greg; Wassink, David; Wong, Alan; Yeoh, Guan

    2002-01-01

    The Australian Nuclear Science and Technology Organisation (ANSTO, formerly AAEC) has been producing fission product Mo-99 in HIFAR, from the irradiation of Low Enrichment Uranium (LEU) UO 2 targets, for nearly thirty years. Over this period, the U-235 enrichment has been increased in stages, from natural to 1.8% to 2.2%. The decision to provide Australia with a replacement research reactor (RRR) for HIFAR has created an ideal opportunity to review and improve the current Mo-99 production process from target design through to chemical processing and waste management options. ANSTO has entered into a collaboration with Argonne National Laboratory (RERTR) to develop a target using uranium metal foil with U-235 enrichment of less than 20% The initial focus has been to demonstrate use of LEU foil targets in HIFAR, using existing irradiation methodology. The current effort focussed on designing a target assembly with optimised thermohydraulic characteristics to accommodate larger LEU foils to meet Mo-99 production needs. The ultimate goal is to produce an LEU target suitable for use in the Replacement Research Reactor when it is commissioned in 2005. This paper reports our activities on: - The regulatory approval processes required in order to undertake irradiation of this new target; -Supporting calculations (neutronics, computational fluid dynamics) for safety submission; - Design challenges and changes to prototype irradiation; - Trial irradiation of LEU foil target in HIFAR; - Future target and rig development program at ANSTO. (author)

  18. 75 FR 10525 - In the Matter of: AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) and All Other...

    Science.gov (United States)

    2010-03-08

    ...: AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) and All Other Persons Who Seek or Obtain... for the Implementation of a Safeguards Information Program (Effective Immediately) I AREVA Enrichment... it to construct and operate a uranium enrichment facility in Bonneville County, Idaho. AES submitted...

  19. Replacement of highly enriched uranium by medium or low-enriched uranium in fuels for research reactors

    International Nuclear Information System (INIS)

    Schwartz, J.P.

    To exclude the possibility of an explosive use of the uranium obtained from an elementary chemical process, one needs to use a fuel less enriched than 20 weight percent in U 235 . This goal can be reached by two ways: 1. The low density fuels, i.e. U or U 3 O 8 /Al fuels. One has to increase their U content from 1.3 g U/cm 3 presently qualified under normal operation conditions. Several manufacturers such as CERCA in France developed these fuels with a near-term objective of about 2 g U/cm 3 and a long-term objective of 3 g U/cm 3 . 2. The high density fuels. They are the UO 2 Caramel plate type fuels now under consideration, and U 3 Si and UMo as a long-term potential

  20. How the First Stars Regulated Star Formation. II. Enrichment by Nearby Supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ke-Jung [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan); Whalen, Daniel J. [Institute of Cosmology and Gravitation, Portsmouth University, Portsmouth (United Kingdom); Wollenberg, Katharina M. J.; Glover, Simon C. O.; Klessen, Ralf S., E-mail: ken.chen@nao.ac.jp [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg (Germany)

    2017-08-01

    Metals from Population III (Pop III) supernovae led to the formation of less massive Pop II stars in the early universe, altering the course of evolution of primeval galaxies and cosmological reionization. There are a variety of scenarios in which heavy elements from the first supernovae were taken up into second-generation stars, but cosmological simulations only model them on the largest scales. We present small-scale, high-resolution simulations of the chemical enrichment of a primordial halo by a nearby supernova after partial evaporation by the progenitor star. We find that ejecta from the explosion crash into and mix violently with ablative flows driven off the halo by the star, creating dense, enriched clumps capable of collapsing into Pop II stars. Metals may mix less efficiently with the partially exposed core of the halo, so it might form either Pop III or Pop II stars. Both Pop II and III stars may thus form after the collision if the ejecta do not strip all the gas from the halo. The partial evaporation of the halo prior to the explosion is crucial to its later enrichment by the supernova.

  1. Automated nuclear fuel rod pattern loading system

    International Nuclear Information System (INIS)

    Lambert, D.V.; Nylund, T.W.; Byers, J.W.; Haley, D.E. Jr.; Cioffi, J.V.

    1991-01-01

    This patent describes a method for loading fuel rods in a desired pattern. It comprises providing a supply of fuel rods of known enrichments; providing a magazine defining a matrix of elongated slots open at their forward ends for receiving fuel rods; defining a fuel rod feed path; receiving successively one at a time along the feed path fuel rods selected from the supply thereof; verifying successively one at a time along the feed path the identity of the selected fuel rods, the verifying including blocking passage of each selected fuel rod along the feed path until the identity of each selected fuel rod is confirmed as correct; feeding to the magazine successively one at a time along the feed path the selective and verified fuel rods; and supporting and moving the magazine along X-Y axes to successively align one at a time selected ones of the slots with the feed path for loading in the magazine the successive fuel rods in a desired enrichment pattern

  2. Flux pinning in MOD YBCO films by chemical doping

    International Nuclear Information System (INIS)

    Zhou, Y X; Ghalsasi, S; Rusakova, I; Salama, K

    2007-01-01

    A novel nanomaterial synthesis technique has been developed to introduce 0D (particles), 1D (columnar defects) and 3D (domains) nanoscale pinning centres in MOD Y 1 Ba 2 Cu 3 O 7 (YBCO) coated conductors. We have succeeded in introducing nanoscale Y enriched particles, nanoscale 90 0 rotated Y 1/3 Sm 2/3 Ba 2 Cu 3 O 7 domains and nanoscale Zr enriched columnar defects into YBCO layers by different chemical doping. The pinning force density in Y 2 O 3 -doped YBCO film is found to be larger than that of pure YBCO film at all fields. Also it was found that YBCO films with Sm substituting for Y have yielded improved critical current density characteristics over a wide range of magnetic fields. Maximum pinning force densities exceeding 7 and 8 GN m -3 are obtained in 5% BZO-doped and Sm substituted YBCO films, respectively. Additionally, TEM studies revealed nanoscale Zr enriched columnar defects distributing in the matrix of the c-oriented YBCO film throughout the whole cross section. This indicates that chemical doping is a promising fabrication technique to create specific pinning landscapes in YBCO coated conductors

  3. Stability of flavoured phytosterol-enriched drinking yogurts during storage as affected by different packaging materials.

    Science.gov (United States)

    Semeniuc, Cristina Anamaria; Cardenia, Vladimiro; Mandrioli, Mara; Muste, Sevastiţa; Borsari, Andrea; Rodriguez-Estrada, Maria Teresa

    2016-06-01

    The aim of this study was to investigate the influence of different packaging materials on storage stability of flavoured phytosterol-enriched drinking yogurts. White vanilla (WV) and blood orange (BO) phytosterol-enriched drinking yogurts conditioned in mono-layer and triple-layer co-extruded plastic bottles were stored at +6 ± 1 °C for 35 days (under alternating 12 h light and 12 h darkness) to simulate shelf-life conditions. Samples were collected at three different storage times and subjected to determination of total sterol content (TSC), peroxide value (PV) and thiobarbituric acid reactive substances (TBARs). TSC was not significantly affected by packaging material or storage time and met the quantity declared on the label. PV was significantly influenced by yogurt type × packaging material × storage time interaction and TBARs by packaging material × storage time interaction. Between the two packaging materials, the triple-layer plastic mini bottle with black coloured and completely opaque intermediate layer offered the best protection against lipid oxidation. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  4. 76 FR 387 - Atomic Safety and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility)

    Science.gov (United States)

    2011-01-04

    ... and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) December 17, 2010... construction and operation of a gas centrifuge uranium enrichment facility--denoted as the Eagle Rock... site at http://www.nrc.gov/materials/fuel-cycle-fac/arevanc.html . These and other documents relating...

  5. Isotopic and chemical investigations on Angra dos Reis

    International Nuclear Information System (INIS)

    Wasserburg, G.J.; Tera, F.; Papanastassiou, D.A.; Huneke, J.C.

    1977-01-01

    Extensive isotopic studies of Pb, Sr and Xe and chemical abundance measurements of K, Rb, Sr, Ba, Nd, Sm, U and Th for total meteorite and mineral separates of the Angra dos Reis achondrite are reported on. U-Pb, Th-Pb and Pb-Pb ages are concordant at 4.54 AE for the total meteorite and for high-purity whitlockite in Angra dos Reis. This establishes Angra dos Reis as an early planetary differentiate which has not been disturbed for these systems since 4.54 AE ago. Measured 87 Sr/ 86 Sr in pyroxene and whitlockite for Angra dos Reis (ADOR) are distinctly below BABI by two parts in 10 4 and only one part in 10 4 above the lowest 87 Sr/ 86 Sr (ALL) measured in an Allende inclusion. The difference in ADOR-ALL corresponds to an interval of condensation in the solar nebula of approximately 3 m.y. If 26 Al was the heat source for the magmatism on the parent planets of Angra dos Reis and the basaltic achondrites (BABI) then the relatively large difference in 87 Sr/ 86 Sr, BABI - ALL, must be the result of planetary evolution rather than condensation over approximately 10 m.y. Xe isotopic measurements confirm the presence of large amounts of 244 Pu-produced fission Xe and show that 244 Pu was enriched in the whitlockite relative to the pyroxene by a factor of approximately 18. Chemical element enrichment factors between the whitlockite and the fassaitic pyroxene in Angra dos Reis are presented. The enrichment factors demonstrate close analogy between the rare earth elements and their actinide analogs. The enrichment factor for Pu is intermediate to the enrichment factors of Nd and Sm. (Auth.)

  6. The effect of a crosslinking chemical reaction on pattern formation in viscous fingering of miscible fluids in a Hele-Shaw cell

    Science.gov (United States)

    Bunton, Patrick H.; Tullier, Michael P.; Meiburg, Eckart; Pojman, John A.

    2017-10-01

    Viscous fingering can occur in fluid motion whenever a high mobility fluid displaces a low mobility fluid in a Darcy type flow. When the mobility difference is primarily attributable to viscosity (e.g., flow between the two horizontal plates of a Hele-Shaw cell), viscous fingering (VF) occurs, which is sometimes termed the Saffman-Taylor instability. Alternatively, in the presence of differences in density in a gravity field, buoyancy-driven convection can occur. These instabilities have been studied for decades, in part because of their many applications in pollutant dispersal, ocean currents, enhanced petroleum recovery, and so on. More recent interest has emerged regarding the effects of chemical reactions on fingering instabilities. As chemical reactions change the key flow parameters (densities, viscosities, and concentrations), they may have either a destabilizing or stabilizing effect on the flow. Hence, new flow patterns can emerge; moreover, one can then hope to gain some control over flow instabilities through reaction rates, flow rates, and reaction products. We report effects of chemical reactions on VF in a Hele-Shaw cell for a reactive step-growth cross-linking polymerization system. The cross-linked reaction product results in a non-monotonic viscosity profile at the interface, which affects flow stability. Furthermore, three-dimensional internal flows influence the long-term pattern that results.

  7. Photon production in an expanding and chemically equilibrating gluon-enriched plasma

    International Nuclear Information System (INIS)

    Kaempfer, B.; Technische Univ. Dresden; Pavlenko, O.P.; AN Ukrainskoj SSR, Kiev

    1993-12-01

    Photon production in a longitudinally and transversely expanding gluon plasma with initially little quark admixture is considered. Chemical equilibration of quarks and gluons is followed by rate equations. The yields of hard photons with E ≥ 2 GeV are insensitive to chemical equilibration and depend mainly on the initial thermalized state. Medium-energy photons with E ∼ 1 GeV are more frequently produced in case of faster equilibration, despite of faster cooling. For an assumed fast equilibration we follow the evolution of matter through mixed and hadron phases. The transverse momentum kick, due to transverse expansion, of photons from hadron matter is shown to be reduced for an equation of state with reduced latent heat. The photon yield in the region E > 1 GeV from deconfined matter dominates for conditions, estimated to be achieved at RHIC, in case of a weakly first-order confinement transition. (orig.)

  8. The low-enrichment fuel development program

    International Nuclear Information System (INIS)

    Stahl, D.

    1993-01-01

    In the 1950s and 1960s, low-power research reactors were built around the world utilized MTR-type fuel elements containing 20% enriched uranium. However, the demand for higher specific power created a need for greater uranium-235 concentrations. Early difficulties in increasing uranium content led to the substitution of highly enriched uranium in place of the 20% enriched fuel previously utilized. The highly enriched material also yielded other benefits including longer core residence time, higher specific reactivity, and somewhat lower cost. Highly enriched material then became readily available and was used for high-power reactors as well as in low-power reactors where 20% enriched material would have sufficed. The trend toward higher and higher specific power also led to the development of the dispersion-type fuels which utilized highly enriched uranium at a concentration of about 40 wt%. In the 1970's, however, concerns were raised about the proliferation resistance of fuels and fuel cycles. As a consequence, the U.S. Department of State has recently prohibited the foreign shipment of highly enriched material, except where prior contractual obligation or special merit exists. This will impact on the availability and utilization of highly enriched uranium for research and test reactor fuel. It has also stimulated development programs on fuels with higher uranium content which would allow the use of uranium of lower enrichment. The purpose of this report is to briefly describe the overall fuel-development program which is coordinated by Argonne National Laboratory for the Department of Energy, and to indicate the current and potential uranium loadings. Other reports will address the individual fuel-development activities in greater detail

  9. Hydrogen-enriched non-premixed jet flames : analysis of the flame surface, flame normal, flame index and Wobbe index

    NARCIS (Netherlands)

    Ranga Dinesh, K.K.J.; Jiang, X.; Oijen, van J.A.

    2014-01-01

    A non-premixed impinging jet flame is studied using three-dimensional direct numerical simulation with detailed chemical kinetics in order to investigate the influence of fuel variability on flame surface, flame normal, flame index and Wobbe index for hydrogen-enriched combustion. Analyses indicate

  10. Gaseous diffusion -- the enrichment workhorse

    International Nuclear Information System (INIS)

    Shoemaker, J.E. Jr.

    1984-01-01

    Construction of the first large-scale gaseous diffusion facility was started as part of the Manhattan Project in Oak Ridge, Tennessee, in 1943. This facility, code named ''K-25,'' began operation in January 1945 and was fully on stream by September 1945. Four additional process buildings were later added in Oak Ridge as the demand for enriched uranium escalated. New gaseous diffusion plants were constructed at Paducah, Kentucky, and Portsmouth, Ohio, during this period. The three gaseous diffusion plants were the ''workhorses'' which provided the entire enriched uranium demand for the United States during the 1950s and 1960s. As the demand for enriched uranium for military purposes decreased during the early 1960s, power to the diffusion plants was curtailed to reduce production. During the 1960s, as plans for the nuclear power industry were formulated, the role of the diffusion plants gradually changed from providing highly-enriched uranium for the military to providing low-enriched uranium for power reactors

  11. ToNER: A tool for identifying nucleotide enrichment signals in feature-enriched RNA-seq data.

    Directory of Open Access Journals (Sweden)

    Yuttachon Promworn

    Full Text Available Biochemical methods are available for enriching 5' ends of RNAs in prokaryotes, which are employed in the differential RNA-seq (dRNA-seq and the more recent Cappable-seq protocols. Computational methods are needed to locate RNA 5' ends from these data by statistical analysis of the enrichment. Although statistical-based analysis methods have been developed for dRNA-seq, they may not be suitable for Cappable-seq data. The more efficient enrichment method employed in Cappable-seq compared with dRNA-seq could affect data distribution and thus algorithm performance.We present Transformation of Nucleotide Enrichment Ratios (ToNER, a tool for statistical modeling of enrichment from RNA-seq data obtained from enriched and unenriched libraries. The tool calculates nucleotide enrichment scores and determines the global transformation for fitting to the normal distribution using the Box-Cox procedure. From the transformed distribution, sites of significant enrichment are identified. To increase power of detection, meta-analysis across experimental replicates is offered. We tested the tool on Cappable-seq and dRNA-seq data for identifying Escherichia coli transcript 5' ends and compared the results with those from the TSSAR tool, which is designed for analyzing dRNA-seq data. When combining results across Cappable-seq replicates, ToNER detects more known transcript 5' ends than TSSAR. In general, the transcript 5' ends detected by ToNER but not TSSAR occur in regions which cannot be locally modeled by TSSAR.ToNER uses a simple yet robust statistical modeling approach, which can be used for detecting RNA 5'ends from Cappable-seq data, in particular when combining information from experimental replicates. The ToNER tool could potentially be applied for analyzing other RNA-seq datasets in which enrichment for other structural features of RNA is employed. The program is freely available for download at ToNER webpage (http://www4a

  12. ToNER: A tool for identifying nucleotide enrichment signals in feature-enriched RNA-seq data.

    Science.gov (United States)

    Promworn, Yuttachon; Kaewprommal, Pavita; Shaw, Philip J; Intarapanich, Apichart; Tongsima, Sissades; Piriyapongsa, Jittima

    2017-01-01

    Biochemical methods are available for enriching 5' ends of RNAs in prokaryotes, which are employed in the differential RNA-seq (dRNA-seq) and the more recent Cappable-seq protocols. Computational methods are needed to locate RNA 5' ends from these data by statistical analysis of the enrichment. Although statistical-based analysis methods have been developed for dRNA-seq, they may not be suitable for Cappable-seq data. The more efficient enrichment method employed in Cappable-seq compared with dRNA-seq could affect data distribution and thus algorithm performance. We present Transformation of Nucleotide Enrichment Ratios (ToNER), a tool for statistical modeling of enrichment from RNA-seq data obtained from enriched and unenriched libraries. The tool calculates nucleotide enrichment scores and determines the global transformation for fitting to the normal distribution using the Box-Cox procedure. From the transformed distribution, sites of significant enrichment are identified. To increase power of detection, meta-analysis across experimental replicates is offered. We tested the tool on Cappable-seq and dRNA-seq data for identifying Escherichia coli transcript 5' ends and compared the results with those from the TSSAR tool, which is designed for analyzing dRNA-seq data. When combining results across Cappable-seq replicates, ToNER detects more known transcript 5' ends than TSSAR. In general, the transcript 5' ends detected by ToNER but not TSSAR occur in regions which cannot be locally modeled by TSSAR. ToNER uses a simple yet robust statistical modeling approach, which can be used for detecting RNA 5'ends from Cappable-seq data, in particular when combining information from experimental replicates. The ToNER tool could potentially be applied for analyzing other RNA-seq datasets in which enrichment for other structural features of RNA is employed. The program is freely available for download at ToNER webpage (http://www4a.biotec.or.th/GI/tools/toner) and Git

  13. Chemical aspects of nuclear fuel fabrication processes

    Energy Technology Data Exchange (ETDEWEB)

    Naylor, A; Ellis, J F; Watson, R H

    1986-04-01

    Processes used by British Nuclear Fuels plc for the conversion of uranium ore concentrates to uranium metal and uranium hexafluoride, are reviewed. Means of converting the latter compound, after enrichment, to sintered UO/sub 2/ fuel bodies are also described. An overview is given of the associated chemical engineering technology.

  14. Pattern formation in arrays of chemical oscillators

    Indian Academy of Sciences (India)

    Chemical oscillators; phase flip; oscillation death. PACS No. 05.45 .... array oscillate (with varying amplitudes and frequencies), while the others experience oscillation death .... Barring the boundary cells, one observes near phase flip and near ...

  15. Dry-plasma-free chemical etch technique for variability reduction in multi-patterning (Conference Presentation)

    Science.gov (United States)

    Kal, Subhadeep; Mohanty, Nihar; Farrell, Richard A.; Franke, Elliott; Raley, Angelique; Thibaut, Sophie; Pereira, Cheryl; Pillai, Karthik; Ko, Akiteru; Mosden, Aelan; Biolsi, Peter

    2017-04-01

    Scaling beyond the 7nm technology node demands significant control over the variability down to a few angstroms, in order to achieve reasonable yield. For example, to meet the current scaling targets it is highly desirable to achieve sub 30nm pitch line/space features at back-end of the line (BEOL) or front end of line (FEOL); uniform and precise contact/hole patterning at middle of line (MOL). One of the quintessential requirements for such precise and possibly self-aligned patterning strategies is superior etch selectivity between the target films while other masks/films are exposed. The need to achieve high etch selectivity becomes more evident for unit process development at MOL and BEOL, as a result of low density films choices (compared to FEOL film choices) due to lower temperature budget. Low etch selectivity with conventional plasma and wet chemical etch techniques, causes significant gouging (un-intended etching of etch stop layer, as shown in Fig 1), high line edge roughness (LER)/line width roughness (LWR), non-uniformity, etc. In certain circumstances this may lead to added downstream process stochastics. Furthermore, conventional plasma etches may also have the added disadvantage of plasma VUV damage and corner rounding (Fig. 1). Finally, the above mentioned factors can potentially compromise edge placement error (EPE) and/or yield. Therefore a process flow enabled with extremely high selective etches inherent to film properties and/or etch chemistries is a significant advantage. To improve this etch selectivity for certain etch steps during a process flow, we have to implement alternate highly selective, plasma free techniques in conjunction with conventional plasma etches (Fig 2.). In this article, we will present our plasma free, chemical gas phase etch technique using chemistries that have high selectivity towards a spectrum of films owing to the reaction mechanism ( as shown Fig 1). Gas phase etches also help eliminate plasma damage to the

  16. Chemical enrichment in isolated barred spiral galaxies.

    Science.gov (United States)

    Martel, Hugo; Carles, Christian; Robichaud, Fidéle; Ellison, Sara L.; Williamson, David J.

    2018-04-01

    To investigate the role of bars in the chemical evolution of isolated disc galaxies, we performed a series of 39 gas dynamical simulations of isolated barred and unbarred galaxies with various masses, initial gas fractions, and AGN feedback models. The presence of a bar drives a substantial amount of gas toward the central region of the galaxy. In the most massive galaxies, this results in a violent starburst, followed by a drop in star formation resulting from gas exhaustion. The time delay between Type Ia and Type II supernovae explosions means that barred galaxies experience a rapid increase in [O/H] in the central region, and a much more gradual increase in [Fe/H]. In unbarred galaxies, star formation proceeds at a slow and steady rate, and oxygen and iron are produced at steady rates which are similar except for a time offset. Comparing the abundance ratios in barred and unbarred galaxies with the same central stellar mass M*, we find in barred galaxies an enhancement of 0.07 dex in [O/H], 0.05 dex in [Fe/H], and 0.05 dex in [O/Fe]. The [O/H] enhancement is in excellent agreement with observations from the SDSS. The initial gas fraction has very little effect on the abundance ratios in barred and unbarred galaxies, unless the galaxies experience a starburst. We considered AGN-host galaxies located near the bottom of the AGN regime, M* ≳ 3 × 1010M⊙, where AGN feedback dominates over supernovae feedback. We found that the impact of AGN feedback on the central abundances is marginal.

  17. Considering the post-1995 enrichment market

    International Nuclear Information System (INIS)

    Gunter, L.

    1994-01-01

    World demand for uranium enrichment services is likely to grow only a little over the next decade, from the current 28 million separative work units (SWU) per year to 33 MSWU per year. Much of the growth will come from Asia where nuclear generating capacity is still increasing. The current situation of the primary enrichment companies is summarized. The primary Western suppliers, Cogema, United States Enrichment Corporation and Urenco, are competing for increased market share in the USA, Europe and Asia as utilities purchase their post-1995 requirements. Entry of the Russian enrichment company, Tenex, into Western markets has been limited by trade restrictions. As a consequence of disarmament, blended weapons material has resulted in a surplus of low-enriched uranium. Together with over-capacity amongst the primary enrichers this has led to an expectation that reduced prices will be negotiable in the medium term. (3 figures). (UK)

  18. Present state of development of uranium enrichment

    International Nuclear Information System (INIS)

    1979-01-01

    The pilot plant for uranium enrichment started the operation on September 12, 1979. The pilot plant has been constructed by the Power Reactor and Nuclear Fuel Development Corp. in Ningyo Pass, Okayama Prefecture. 7000 centrifugal separators will be installed by mid 1981, and yearly production of 70 t SWU is expected. The Uranium Enrichment Committee of Japan Atomic Industrial Forum has made the proposal on the method of forwarding the development of uranium enrichment in Japan to Atomic Energy Commission and related government offices in December, 1978. This survey summarized the trends of uranium enrichment in Japan and foreign countries and the problems about nuclear non-proliferation, and provides with the reference materials. The demand and supply of uranium enrichment in the world, the present states and plans in USA, Europe, USSR and others, the demand and supply of uranium enrichment and the measures for securing it in Japan, the present state and future plan of uranium enrichment project in Japan, the international regulation of uranium enrichment, the recent policy of USA and INFCE, and the trend of the regulation of utilizing enriched uranium are described. Moreover, the concept of separation works in uranium enrichment and the various technologies of separation are explained. (Kako, I.)

  19. Effect of mass loss on the chemical yields from massive stars

    Energy Technology Data Exchange (ETDEWEB)

    Chiosi, C; Caimmi, R [Padua Univ. (Italy). Istituto di Astronomia

    1979-01-01

    Recent results on the calculation of the chemical yields from massive stars, are rediscussed by taking into account the occurrence of mass loss by stellar wind during the core H- and He-burning phases. The new yields are found to be compatible with the observed distribution of chemical abundances in the solar system, except for He. The net enrichment of several elements over the galaxy's lifetime is found to be consistent with the current estimate of the star formation rate, if we adopt a two phase process of galaxy formation (halodisk). The relative He to heavy element enrichment rate ..delta..Y/..delta..Z turns out to agree with the observational value when mass loss by stellar wind is taken into account.

  20. Aqueous chemical growth and patterning of ZnO nanopillars on different substrate materials

    Energy Technology Data Exchange (ETDEWEB)

    Kreye, M.; Postels, B.; Wehmann, H.H.; Waag, A. [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, 38106 Braunschweig (Germany)

    2006-03-15

    Aqueous chemical growth (ACG) is a low-temperature approach that is only weakly influenced by the substrate and allows for the growth of ZnO nanopillars on various substrates. ACG is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars even on polymer materials. Photoluminescence (PL) characterisation clearly shows a comparatively strong band-edge luminescence even at room temperature that is accompanied with a rather weak visible luminescence in the yellow/orange spectral range. We introduce a rather simple postgrowth lithographic technique. Patterning of ZnO nanopillars even on layered conducting and flexible substrate materials using ACG as a low-temperature growth technique is demonstrated. The economical potential for future applications and devices using ZnO nanopillar arrays is discussed. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Inoculation stress hypothesis of environmental enrichment.

    Science.gov (United States)

    Crofton, Elizabeth J; Zhang, Yafang; Green, Thomas A

    2015-02-01

    One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy System

    Science.gov (United States)

    Hasselquist, Sten; Shetrone, Matthew D.; Smith, Verne V.; Holtzman, Jon A.; McWilliam, Andrew; APOGEE Team

    2018-06-01

    The Apache Point Observatory Galactic Evolution Experiment provides the opportunity of measuring elemental abundances for C, N, O, Na, Mg, Al, Si, P, K, Ca, V, Cr, Mn, Fe, Co, and Ni in vast numbers of stars. We analyze the chemical-abundance patterns of these elements for 158 red giant stars belonging to the Sagittarius dwarf galaxy (Sgr). This is the largest sample of Sgr stars with detailed chemical abundances, and it is the first time that C, N, P, K, V, Cr, Co, and Ni have been studied at high resolution in this galaxy. We find that the Sgr stars with [Fe/H] > -0.8 are deficient in all elemental abundance ratios (expressed as [X/Fe]) relative to the Milky Way, suggesting that the Sgr stars observed today were formed from gas that was less enriched by Type II SNe than stars formed in the Milky Way. By examining the relative deficiencies of the hydrostatic (O, Na, Mg, and Al) and explosive (Si, P, K, and Mn) elements, our analysis supports the argument that previous generations of Sgr stars were formed with a top-light initial mass function, one lacking the most massive stars that would normally pollute the interstellar medium with the hydrostatic elements. We use a simple chemical-evolution model, flexCE, to further support our claim and conclude that recent stellar generations of Fornax and the Large Magellanic Cloud could also have formed according to a top-light initial mass function. We then exploit the unique chemical abundance patters of the Sgr core to trace stars belonging to the Sgr tidal streams elsewhere in the Milky Way.

  3. Design of chemical plant

    International Nuclear Information System (INIS)

    Lee, Dong Il; Kim, Seung Jae; Yang, Jae Ho; Ryu, Hwa Won

    1993-01-01

    This book describes design of chemical plant, which includes chemical engineer and plan for chemical plant, development of chemical process, cost engineering pattern, design and process development, general plant construction plan, project engineering, foundation for economy on assets and depreciation, estimation for cost on capital investment and manufacturing cost, design with computers optimal design and method like fluid mechanics design chemical device and estimation for cost, such as dispatch of material and device writing on design report and appendixes.

  4. Magneto-capillary valve for integrated purification and enrichment of nucleic acids and proteins.

    Science.gov (United States)

    den Dulk, Remco C; Schmidt, Kristiane A; Sabatté, Gwénola; Liébana, Susana; Prins, Menno W J

    2013-01-07

    We describe the magneto-capillary valve (MCV) technology, a flexible approach for integrated biological sample preparation within the concept of stationary microfluidics. Rather than moving liquids in a microfluidic device, discrete units of liquid are present at fixed positions in the device and magnetic particles are actuated between the fluids. The MCV concept is characterized by the use of two planar surfaces at a capillary mutual distance, with specific features to confine the fluids by capillary forces, and the use of a gas or a phase-change material separating the stationary aqueous liquids. We have studied the physics of magneto-capillary valving by quantifying the magnetic force as a function of time and position, which reveals the balance of magnetic, capillary and frictional forces in the system. By purification experiments with a fluorescent tracer we have measured the amount of co-transported liquid, which is a key parameter for efficient purification. To demonstrate the versatility of the technology, several MCV device architectures were tested in a series of biological assays, showing the purification and enrichment of nucleic acids and proteins. Target recovery comparable to non-miniaturized commercial kits was observed for the extraction of DNA from human cells in buffer, using a device architecture with patterned air valves. Experiments using an enrichment module and patterned air valves demonstrate a 40-fold effective enrichment of DNA in buffer. DNA was also successfully purified from blood plasma using paraffin phase-change valves. Finally, the enrichment of a protein biomarker (prostate-specific antigen) using geometrical air valves resulted in a 7-fold increase of detection signal. The MCV technology is versatile, offers extensive freedom for the design of fully integrated systems, and is expected to be manufacturable in a cost-effective way. We conclude that the MCV technology can become an important enabling technology for point

  5. Recommendations to the NRC on acceptable standard format and content for the Fundamental Nuclear Material Control (FNMC) Plan required for low-enriched uranium enrichment facilities

    International Nuclear Information System (INIS)

    Moran, B.W.; Belew, W.L.; Hammond, G.A.; Brenner, L.M.

    1991-11-01

    A new section, 10 CFR 74.33, has been added to the material control and accounting (MC ampersand A) requirements of 10 CFR Part 74. This new section pertains to US Nuclear Regulatory Commission (NRC)-licensed uranium enrichment facilities that are authorized to produce and to possess more than one effective kilogram of special nuclear material (SNM) of low strategic significance. The new section is patterned after 10 CFR 74.31, which pertains to NRC licensees (other than production or utilization facilities licensed pursuant to 10 CFR Part 50 and 70 and waste disposal facilities) that are authorized to possess and use more than one effective kilogram of unencapsulated SNM of low strategic significance. Because enrichment facilities have the potential capability of producing SNM of moderate strategic significance and also strategic SNM, certain performance objectives and MC ampersand A system capabilities are required in 10 CFR 74.33 that are not contained in 10 CFR 74.31. This document recommends to the NRC information that the licensee or applicant should provide in the fundamental nuclear material control (FNMC) plan. This document also describes methods that should be acceptable for compliance with the general performance objectives. While this document is intended to cover various uranium enrichment technologies, the primary focus at this time is gas centrifuge and gaseous diffusion

  6. Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist process: III. Post exposure baking on quartz substrates

    Science.gov (United States)

    Kozawa, Takahiro

    2015-09-01

    Electron beam (EB) lithography is a key technology for the fabrication of photomasks for ArF immersion and extreme ultraviolet (EUV) lithography and molds for nanoimprint lithography. In this study, the temporal change in the chemical gradient of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) was calculated until it became constant, independently of postexposure baking (PEB) time, to clarify the feasibility of single nano patterning on quartz substrates using EB lithography with chemically amplified resist processes. When the quencher diffusion constant is the same as the acid diffusion constant, the maximum chemical gradient of the line-and-space pattern with a 7 nm quarter-pitch did not differ much from that with a 14 nm half-pitch under the condition described above. Also, from the viewpoint of process control, a low quencher diffusion constant is considered to be preferable for the fabrication of line-and-space patterns with a 7 nm quarter-pitch on quartz substrates.

  7. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone

    Directory of Open Access Journals (Sweden)

    Zhe eZhang

    2013-03-01

    Full Text Available Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein 3 implicate that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  8. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone.

    Science.gov (United States)

    Zhang, Zhe; Voothuluru, Priyamvada; Yamaguchi, Mineo; Sharp, Robert E; Peck, Scott C

    2013-01-01

    Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM) proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein implicates that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  9. Noble gas enrichment studies at JET

    International Nuclear Information System (INIS)

    Groth, M.; Andrew, P.; Fundamenski, W.; Guo, H.Y.; Hillis, D.L.; Hogan, J.T.; Horton, L.D.; Matthews, G.F.; Meigs, A.G.; Morgan, P.M.; Stamp, M.F.; Hellermann, M. von

    2001-01-01

    Adequate helium exhaust has been achieved in reactor-relevant ELMy H-mode plasmas in JET performed in the MKII AP and MKII GB divertor geometry. The divertor-characteristic quantities of noble gas compression and enrichment have been experimentally inferred from Charge Exchange Recombination Spectroscopy measurements in the core plasma, and from spectroscopic analysis of a Penning gauge discharge in the exhaust gas. The retention of helium was found to be satisfactory for a next-step device, with enrichment factors exceeding 0.1. The helium enrichment decreases with increasing core plasma density, while the neon enrichment has the opposite behaviour. Analytic and numerical analyses of these plasmas using the divertor impurity code package DIVIMP/NIMBUS support the explanation that the enrichment of noble gases depends significantly on the penetration depth of the impurity neutrals with respect to the fuel atoms. Changes of the divertor plasma configuration and divertor geometry have no effect on the enrichment

  10. Extraosseus enrichments in bone scintigraphy

    International Nuclear Information System (INIS)

    Jochens, R.; Schumacher, T.; Amthauer, H.; Wolter, M.; Stock, W.; Stroszczynski, C.; Moersler, J.P.; Eichstaedt, H.

    1996-01-01

    Extraosseus enrichments are common findings in bone scintigraphy. Main causes are artifacts by skin or cloth contamination, paravenous and subcutaneous injection. Physical examination, removal of cloths, skin cleaning or further images in differing projections lead to the correct diagnosis artefact or extraosseous enrichments. Further on, extraosseous enrichments are seen in physiological variants. In different diseases extraosseous enrichments are common, especially in urinary tract, liver and extremities. Further diagnostics, e.g. conventional radiologic procedures, sonography and CT scans, have to be performed. In individual cases side results in bone scintigraphy lead to formerly unknown diagnosis, further diagnostic procedure is influenced decisively. Own cases show for example a cerebral apoplectic insult, formerly unknown liver metastasis or metastasis in extraosseous Ewings's sarcoma. (orig.) [de

  11. Report of the Subcommittee on Domestic Uranium Enrichment

    International Nuclear Information System (INIS)

    1981-01-01

    A report by the Subcommittee on Domestic Uranium Enrichment to the Atomic Energy Commission is described; which covers the procedure of the domestic uranium enrichment by centrifugal process up to the commercial production, reviewing the current situation in this field. Domestic uranium enrichment is important in the aspects of securing stable enrichment service, establishing sound fuel cycle, and others. As the future target, the production around the year 2000 is set at 3,000 tons SWU per year at least. The business of uranium enrichment, which is now developed in the Power Reactor and Nuclear Fuel Development Corporation, is to be carried out by private enterprise. The contents are as follows: demand and supply balance of uranium enrichment service, significance of domestic uranium enrichment, evaluation of centrifugal uranium enrichment technology, the target of domestic uranium enrichment, the policy of domestic uranium enrichment promotion. (J.P.N.)

  12. 31 CFR 540.316 - Uranium enrichment.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium enrichment. 540.316 Section 540.316 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF... REGULATIONS General Definitions § 540.316 Uranium enrichment. The term uranium enrichment means the process of...

  13. Enabling complex nanoscale pattern customization using directed self-assembly.

    Science.gov (United States)

    Doerk, Gregory S; Cheng, Joy Y; Singh, Gurpreet; Rettner, Charles T; Pitera, Jed W; Balakrishnan, Srinivasan; Arellano, Noel; Sanders, Daniel P

    2014-12-16

    Block copolymer directed self-assembly is an attractive method to fabricate highly uniform nanoscale features for various technological applications, but the dense periodicity of block copolymer features limits the complexity of the resulting patterns and their potential utility. Therefore, customizability of nanoscale patterns has been a long-standing goal for using directed self-assembly in device fabrication. Here we show that a hybrid organic/inorganic chemical pattern serves as a guiding pattern for self-assembly as well as a self-aligned mask for pattern customization through cotransfer of aligned block copolymer features and an inorganic prepattern. As informed by a phenomenological model, deliberate process engineering is implemented to maintain global alignment of block copolymer features over arbitrarily shaped, 'masking' features incorporated into the chemical patterns. These hybrid chemical patterns with embedded customization information enable deterministic, complex two-dimensional nanoscale pattern customization through directed self-assembly.

  14. Wading bird guano enrichment of soil nutrients in tree islands of the Florida Everglades

    Energy Technology Data Exchange (ETDEWEB)

    Irick, Daniel L. [University of Florida, Soil and Water Science Department, Tropical Research and Education Center, 18905 SW 280th St., Homestead, FL 33031 (United States); Gu, Binhe [University of Florida, Soil and Water Science Department, 2181 McCarty Hall, Gainesville, FL 32611 (United States); Li, Yuncong C., E-mail: yunli@ufl.edu [University of Florida, Soil and Water Science Department, Tropical Research and Education Center, 18905 SW 280th St., Homestead, FL 33031 (United States); Inglett, Patrick W. [University of Florida, Soil and Water Science Department, 2181 McCarty Hall, Gainesville, FL 32611 (United States); Frederick, Peter C. [University of Florida, Department of Wildlife Ecology and Conservation, 110 Newins-Ziegler Hall, PO Box 110430, Gainesville, FL 32611 (United States); Ross, Michael S. [Florida International University, Department of Earth and Environment, Southeast Environmental Research Center, 11200 SW 8th St, Miami, FL 33199 (United States); Wright, Alan L. [University of Florida, Soil and Water Science Department, Everglades Research and Education Center, 3200 E. Palm Beach Rd., Belle Glade, FL 33430 (United States); Ewe, Sharon M.L. [Ecology and Environment, Inc., 12300 South Shore Blvd, Wellington, FL 33414 (United States)

    2015-11-01

    Differential distribution of nutrients within an ecosystem can offer insight of ecological and physical processes that are otherwise unclear. This study was conducted to determine if enrichment of phosphorus (P) in tree island soils of the Florida Everglades can be explained by bird guano deposition. Concentrations of total carbon, nitrogen (N), and P, and N stable isotope ratio (δ{sup 15}N) were determined on soil samples from 46 tree islands. Total elemental concentrations and δ{sup 15}N were determined on wading bird guano. Sequential chemical extraction of P pools was also performed on guano. Guano contained between 53.1 and 123.7 g-N kg{sup −1} and 20.7 and 56.7 g-P kg{sup −1}. Most of the P present in guano was extractable by HCl, which ranged from 82 to 97% of the total P. Total P of tree islands classified as having low or high P soils averaged 0.71 and 40.6 g kg{sup −1}, respectively. Tree island soil with high total P concentration was found to have a similar δ{sup 15}N signature and total P concentration as bird guano. Phosphorus concentrations and δ{sup 15}N were positively correlated in tree island soils (r = 0.83, p < 0.0001). Potential input of guano with elevated concentrations of N and P, and {sup 15}N enriched N, relative to other sources suggests that guano deposition in tree island soils is a mechanism contributing to this pattern. - Highlights: • Tree island soil P concentration and δ{sup 15}N values exceed other Everglades soils. • Characteristics of Everglades tree island soil may indicate guano deposition. • Deposition of stable guano P can exceed other P sources to tree island soil.

  15. Forging patterns and making waves from biology to geology: a commentary on Turing (1952) 'The chemical basis of morphogenesis'.

    Science.gov (United States)

    Ball, Philip

    2015-04-19

    Alan Turing was neither a biologist nor a chemist, and yet the paper he published in 1952, 'The chemical basis of morphogenesis', on the spontaneous formation of patterns in systems undergoing reaction and diffusion of their ingredients has had a substantial impact on both fields, as well as in other areas as disparate as geomorphology and criminology. Motivated by the question of how a spherical embryo becomes a decidedly non-spherical organism such as a human being, Turing devised a mathematical model that explained how random fluctuations can drive the emergence of pattern and structure from initial uniformity. The spontaneous appearance of pattern and form in a system far away from its equilibrium state occurs in many types of natural process, and in some artificial ones too. It is often driven by very general mechanisms, of which Turing's model supplies one of the most versatile. For that reason, these patterns show striking similarities in systems that seem superficially to share nothing in common, such as the stripes of sand ripples and of pigmentation on a zebra skin. New examples of 'Turing patterns' in biology and beyond are still being discovered today. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

  16. Searching for chemical classes among metal-poor stars using medium-resolution spectroscopy

    Science.gov (United States)

    Cruz, Monique A.; Cogo-Moreira, Hugo; Rossi, Silvia

    2018-04-01

    Astronomy is in the era of large spectroscopy surveys, with the spectra of hundreds of thousands of stars in the Galaxy being collected. Although most of these surveys have low or medium resolution, which makes precise abundance measurements not possible, there is still important information to be extracted from the available data. Our aim is to identify chemically distinct classes among metal-poor stars, observed by the Sloan Digital Sky Survey, using line indices. The present work focused on carbon-enhanced metal-poor (CEMP) stars and their subclasses. We applied the latent profile analysis technique to line indices for carbon, barium, iron and europium, in order to separate the sample into classes with similar chemical signatures. This technique provides not only the number of possible groups but also the probability of each object to belong to each class. The method was able to distinguish at least two classes among the observed sample, with one of them being probable CEMP stars enriched in s-process elements. However, it was not able to separate CEMP-no stars from the rest of the sample. Latent profile analysis is a powerful model-based tool to be used in the identification of patterns in astrophysics. Our tests show the potential of the technique for the attainment of additional chemical information from `poor' data.

  17. Directed Self-Assembly of Triblock Copolymer on Chemical Patterns for Sub-10-nm Nanofabrication via Solvent Annealing.

    Science.gov (United States)

    Xiong, Shisheng; Wan, Lei; Ishida, Yoshihito; Chapuis, Yves-Andre; Craig, Gordon S W; Ruiz, Ricardo; Nealey, Paul F

    2016-08-23

    Directed self-assembly (DSA) of block copolymers (BCPs) is a leading strategy to pattern at sublithographic resolution in the technology roadmap for semiconductors and is the only known solution to fabricate nanoimprint templates for the production of bit pattern media. While great progress has been made to implement block copolymer lithography with features in the range of 10-20 nm, patterning solutions below 10 nm are still not mature. Many BCP systems self-assemble at this length scale, but challenges remain in simultaneously tuning the interfacial energy atop the film to control the orientation of BCP domains, designing materials, templates, and processes for ultra-high-density DSA, and establishing a robust pattern transfer strategy. Among the various solutions to achieve domains that are perpendicular to the substrate, solvent annealing is advantageous because it is a versatile method that can be applied to a diversity of materials. Here we report a DSA process based on chemical contrast templates and solvent annealing to fabricate 8 nm features on a 16 nm pitch. To make this possible, a number of innovations were brought in concert with a common platform: (1) assembling the BCP in the phase-separated, solvated state, (2) identifying a larger process window for solvated triblock vs diblock BCPs as a function of solvent volume fraction, (3) employing templates for sub-10-nm BCP systems accessible by lithography, and (4) integrating a robust pattern transfer strategy by vapor infiltration of organometallic precursors for selective metal oxide synthesis to prepare an inorganic hard mask.

  18. Distribution of uranium supply and enrichment

    International Nuclear Information System (INIS)

    Bamford, F.W.

    1982-01-01

    Uranium supply and demand is examined from the perspective of companies in the uranium hexafluoride (UF6) conversion business whose main interest is their sources of uranium supply and UF6 destinations because of transportation costs. Because of the variations in yellowcake transport, charges for conversion, and UF6 transport costs, most converters don't have standard prices. Companies try to look ahead to determine patterns of supplies and delivery points when they analyze the market and estimate future prices. Market analyses must take into account the purchasing policies of utilities around the world. The presentation shows North America supplying about 40% of world uranium, with about 13% of the enrichment done elsewhere. It also shows North American converters getting 53% of the business, but that will require importing uranium from outside North America. 6 tables

  19. Exploring the Origins of Deuterium Enrichments in Solar Nebular Organics

    Science.gov (United States)

    Cleeves, L. Ilsedore; Bergin, Edwin A.; O'D. Alexander, Conel M.; Du, Fujun; Graninger, Dawn; Öberg, Karin I.; Harries, Tim J.

    2016-03-01

    Deuterium-to-hydrogen (D/H) enrichments in molecular species provide clues about their original formation environment. The organic materials in primitive solar system bodies generally have higher D/H ratios and show greater D/H variation when compared to D/H in solar system water. We propose this difference arises at least in part due to (1) the availability of additional chemical fractionation pathways for organics beyond that for water, and (2) the higher volatility of key carbon reservoirs compared to oxygen. We test this hypothesis using detailed disk models, including a sophisticated, new disk ionization treatment with a low cosmic-ray ionization rate, and find that disk chemistry leads to higher deuterium enrichment in organics compared to water, helped especially by fractionation via the precursors CH2D+/CH3+. We also find that the D/H ratio in individual species varies significantly depending on their particular formation pathways. For example, from ˜20-40 au, CH4 can reach {{D}}/{{H}}˜ 2× {10}-3, while D/H in CH3OH remains locally unaltered. Finally, while the global organic D/H in our models can reproduce intermediately elevated D/H in the bulk hydrocarbon reservoir, our models are unable to reproduce the most deuterium-enriched organic materials in the solar system, and thus our model requires some inheritance from the cold interstellar medium from which the Sun formed.

  20. Enrichment of anaerobic syngas-converting bacteria from thermophilic bioreactor sludge.

    Science.gov (United States)

    Alves, Joana I; Stams, Alfons J M; Plugge, Caroline M; Alves, M Madalena; Sousa, Diana Z

    2013-12-01

    Thermophilic (55 °C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2 , and CO2 ) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate - cultures T-Syn-CO. Incubation with syngas and CO caused a rapid decrease in the microbial diversity of the anaerobic consortium. T-Syn and T-Syn-CO showed identical microbial composition and were dominated by Desulfotomaculum and Caloribacterium species. Incubation initiated with CO resulted in the enrichment of bacteria from the genera Thermincola and Thermoanaerobacter. Methane was detected in the first two to three transfers of T-Syn, but production ceased afterward. Acetate was the main product formed by T-Syn and T-Syn-CO. Enriched T-CO cultures showed a two-phase conversion, in which H2 was formed first and then converted to acetate. This research provides insight into how thermophilic anaerobic communities develop using syngas/CO as sole energy and carbon source can be steered for specific end products and subsequent microbial synthesis of chemicals. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  1. The reduced enrichment program for JRR-4

    International Nuclear Information System (INIS)

    Takayanagi, M.

    1992-01-01

    Japan Research Reactor No. 4(JRR-4) with the rated power of 3.5 MW, swimming pool type research reactor, 93 % enriched uranium ETR-type fuel used, light water moderated and cooled. The first criticality reached on 28th January, 1965. The reactor has operated for about 26 years. However, it was planed to the reduced enrichment of the fuels to low enrichment according to the International Reduced Enrichment for Research and Test Reactors (RERTR) program. This paper describes the program for conversion of the enrichment of fuel from 93 % to less than 20 %. (author)

  2. The Regional Patterns of Chemical Composition in the Otolith Core of Larval Fish

    Science.gov (United States)

    Chang, M. Y.; Geffen, A. J.; Nash, R. D. M.; Clemmesen, C.

    2012-04-01

    The elemental composition of fish otoliths can record the environmental information because once a trace element is deposited in the otolith; it presents a permanent record of the environmental conditions experienced by the fish at a particular time. The elemental signature of the otolith nucleus, the area lying within the first annual growth ring, is likely to be characteristic of the nursery areas of the species, and could be used as biological tracer for tracking origin and dispersal. However, ocean acidification may alter otolith growth and element incorporation, and it is important to establish baseline information about the sources of variation - both biotic and abiotic. The objectives of this study, as part of the wider CalMarO network, is to examine the regional differences in the otolith cores of selected fish species, contrast these differences with those measured between these same species in areas where their larvae co-exist and to find out the maternal effect to the chemical composition during the first forming of otoliths. The laboratory and field experiments were included to produce otolith material reflecting the maternal and regional patterns. Otolith composition was measured using laser-ablation ICPMS. For clarifying the regional patterns, juveniles from six locations and seven spawning groups along the west of the British Isles and larvae from the North Sea were sampled to distinguish the origin of spawning herring. There are three main nursery-ground groups, the Irish Sea, Scottish sea lochs and the Minch, contributing to the spawning herring in the west of the British Isles according to the otolith elemental composition data. However, the spawning origin of the North Sea herring larvae was still unclear. The otolith concentrations of Li, Na, Mg, Mn, Cu, Ru and Sr were significantly different among nursery-ground populations. Together with length-at-age data, at least two nursery-ground groups contributed to each spawning population. The

  3. Detection of creatinine enriched on a surface imprinted polystyrene film using FT-ATR-IR.

    Science.gov (United States)

    Sreenivasan, K

    2006-01-01

    The surface of polystyrene (PS) was chemically modified by coating a thin layer of polyaniline (PANI) by oxidizing aniline using ammonium persulfate. Affinity sites for creatinine, a clinically relevant molecule, were created in the coated layer by adding creatinine as print molecules during the oxidation. The imprinted layer adsorbed creatinine was compared to non-imprinted surface reflecting the creation of creatinine-specific sites on the surface. The equilibrium was attained rapidly, indicating that a material of this kind is suitable for sensing applications. The adsorbed creatinine on the surface was detected using the technique of Fourier transform attenuated total internal reflection infra red spectroscopy (FT-ATR-IR). The results show that molecularly imprinted surface can enrich molecules of interest and the enriched molecules can be detected using FT-IR.

  4. Subtle Gardeners: Inland Predators Enrich Local Topsoils and Enhance Plant Growth.

    Science.gov (United States)

    Fedriani, José M; Garrote, Pedro José; Delgado, María del Mar; Penteriani, Vincenzo

    2015-01-01

    Inland vertebrate predators could enrich of nutrients the local top soils in the area surrounding their nests and dens by depositing faeces, urine, and prey remains and, thus, alter the dynamics of plant populations. Surprisingly, and in contrast with convincing evidence from coastal habitats, whether and how this phenomenon occurs in inland habitats is largely uncertain even though these habitats represent a major fraction of the earth's surface. We investigated during two consecutive breeding seasons the potential enrichment of the top-soils associated with inland ground-nesting eagle owls Bubo bubo, as well as its possible consequences in the growth of two common annual grasses in southern Spain. Top-soils associated with owl nests differed strongly and significantly from control top-soils in chemical parameters, mainly fertility-related properties. Specifically, levels of available phosphorus, total nitrogen, organic matter, and available potassium were 49.1, 5.6, 3.1, and 2.7 times higher, respectively, in top-soils associated with owl nests as compared to control top-soils. Germination experiments in chambers indicated that nutrient enrichment by nesting owls enhanced seedling growth in both annual grasses (Phalaris canariensis and Avena sativa), with seedling size being 1.4-1.3 times higher in owl nest top-soils than in control top-soils. Our experimental study revealed that pervasive inland, predatory birds can profoundly enrich the topsoil around their nests and, thus, potentially enhance local vegetation growth. Because diverse inland vertebrate predators are widespread in most habitats they have a strong potential to enhance spatial heterogeneity, impinge on plant communities, and exert an overlooked effect on primary productivity worldwide.

  5. Subtle Gardeners: Inland Predators Enrich Local Topsoils and Enhance Plant Growth.

    Directory of Open Access Journals (Sweden)

    José M Fedriani

    Full Text Available Inland vertebrate predators could enrich of nutrients the local top soils in the area surrounding their nests and dens by depositing faeces, urine, and prey remains and, thus, alter the dynamics of plant populations. Surprisingly, and in contrast with convincing evidence from coastal habitats, whether and how this phenomenon occurs in inland habitats is largely uncertain even though these habitats represent a major fraction of the earth's surface. We investigated during two consecutive breeding seasons the potential enrichment of the top-soils associated with inland ground-nesting eagle owls Bubo bubo, as well as its possible consequences in the growth of two common annual grasses in southern Spain. Top-soils associated with owl nests differed strongly and significantly from control top-soils in chemical parameters, mainly fertility-related properties. Specifically, levels of available phosphorus, total nitrogen, organic matter, and available potassium were 49.1, 5.6, 3.1, and 2.7 times higher, respectively, in top-soils associated with owl nests as compared to control top-soils. Germination experiments in chambers indicated that nutrient enrichment by nesting owls enhanced seedling growth in both annual grasses (Phalaris canariensis and Avena sativa, with seedling size being 1.4-1.3 times higher in owl nest top-soils than in control top-soils. Our experimental study revealed that pervasive inland, predatory birds can profoundly enrich the topsoil around their nests and, thus, potentially enhance local vegetation growth. Because diverse inland vertebrate predators are widespread in most habitats they have a strong potential to enhance spatial heterogeneity, impinge on plant communities, and exert an overlooked effect on primary productivity worldwide.

  6. Competing for the non-US enrichment markets

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The article discusses three basic steps: first, the historical perspectives; second, where the enrichment industry and the non-US markets for enrichment stand today (the present situation); and third, the likely future developments, which, for practical purposes, are dealt with in two parts: the non-US enrichment markets in the 1980s; and the non-US enrichment markets beyond the 1980s;

  7. Enriched uranium sales: effect on supply industry

    International Nuclear Information System (INIS)

    Andersen, R.K.

    1985-01-01

    The subject is covered in sections: introduction (combined effect of low-enriched uranium (LEU) inventory sales and utility services enrichment contract terms); enrichment market overview; enrichment market dynamics; the reaction of the US Department of Energy; elimination of artificial demand; draw down of inventories; purchase and sale of LEU inventories; tails assay option; unfulfilled requirements for U 3 O 8 ; conclusions. (U.K.)

  8. U.S. forms uranium enrichment corporation

    International Nuclear Information System (INIS)

    Seltzer, R.

    1993-01-01

    After almost 40 years of operation, the federal government is withdrawing from the uranium enrichment business. On July 1, the Department of Energy turned over to a new government-owned entity--the US Enrichment Corp. (USEC)--both the DOE enrichment plants at Paducah, Ky., and Portsmouth, Ohio, and domestic and international marketing of enriched uranium from them. Pushed by the inability of DOE's enrichment operations to meet foreign competition, Congress established USEC under the National Energy Policy Act of 1992, envisioning the new corporation as the first step to full privatization. With gross revenues of $1.5 billion in fiscal 1992, USEC would rank 275th on the Fortune 500 list of top US companies. USEC will lease from DOE the Paducah and Portsmouth facilities, built in the early 1950s, which use the gaseous diffusion process for uranium enrichment. USEC's stock is held by the US Treasury, to which it will pay annual dividends. Martin Marietta Energy Systems, which has operated Paducah since 1984 and Portsmouth since 1986 for DOE, will continue to operate both plants for USEC. Closing one of the two facilities will be studied, especially in light of a 40% world surplus of capacity over demand. USEC also will consider other nuclear-fuel-related ventures. USEC will produce only low-enriched uranium, not weapons-grade material. Indeed, USEC will implement a contract now being completed under which the US will purchase weapons-grade uranium from dismantled Russian nuclear weapons and convert it into low-enriched uranium for power reactor fuel

  9. Coastal Antarctic aerosol: the seasonal pattern of its chemical composition and radionuclide content

    International Nuclear Information System (INIS)

    Wagenbach, D.; Goerlach, U.; Moser, K.; Muennich, K.O.

    1988-01-01

    At the German Antarctic research station (70 degrees S, 8 degrees W), long-term observations of the chemical and radio-chemical composition of atmospheric particulate matter were started in spring 1983. Based on the analysis of high-volume aerosol filters sampled continuously for nearly 5 years, concentration records of the following aerosol components are presented here: (a) major ions (sea-salt, sulfate, nitrate); (b) cosmogenic 7 Be and terrigeneous 210 Pb; (c) trace elements (crustal Mn, heavy metal Pb). All species mentioned, with the exception of stable and radioactive Pb, show annual cycles. The maximum occurs in austral summer for 7 Be, sulfate, and crustal Mn. For sea-salt, however, the maximum is found in local autumn, and for nitrate in local spring. In local summer, the enhanced 7 Be to 210 Pb ratio is attributed to intenser large scale vertical mixing. The pattern of total sulfate seems to be controlled by the nss-sulfate production from marine organo-sulfur species during local summer, whereas in polar night, nss-sulfate shows very low or even negative concentration. Crustal aerosol (indicated by Mn) shows a mean summer contribution of 16 ng/SCM which exceeds the mean winter level by more than a factor of two. Based on a mean wash-out ratio of 0.27x10 6 observed for 210 Pb bearing aerosol particles, a Pb snow concentration of 3.0 pg/g is deduced from the mean air concentration of 11 pg/SCM. (authors)

  10. Uranium Conversion & Enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U3O8 yellowcake into UF6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

  11. Uranium enrichment. Technology, economics, capacity

    International Nuclear Information System (INIS)

    Voigt, W.R. Jr.; Saire, D.E.; Gestson, D.K.; Peske, S.E.; Vanstrum, P.R.

    1983-01-01

    Large-scale enrichment of uranium has now been carried out for 40 years. While the gaseous diffusion process was the original choice of several countries and continues today to provide the major component of the world production of separative work, the last two decades have witnessed the development of a number of alternative processes for enrichment. These processes, which are being studied and deployed around the world, offer a wide range of technical and economic characteristics which will be useful in assuring adequate capacity to meet projected reactor fuel market needs through the rest of this century at competitive prices. With present uncertainties in future enriched uranium needs, it is apparent that flexibility in the deployment and operation of any enrichment process will be one of the prime considerations for the future. More economical production of separative work not only can have a beneficial impact on reactor fuel costs, but also tends to conserve natural uranium resources. This paper reviews the world scene in the enrichment component of the fuel cycle, including existing or planned commercial-scale facilities and announced R+D efforts on various processes. (author)

  12. Uranium enrichment: technology, economics, capacity

    Energy Technology Data Exchange (ETDEWEB)

    Voigt, Jr., W. R.; Vanstrum, P. R.; Saire, D. E.; Gestson, D. K.; Peske, S. E.

    1982-08-01

    Large-scale enrichment of uranium has now been carried out for 40 years. While the gaseous diffusion process was the original choice of several countries and continues today to provide the major component of the world production of separative work, the last two decades have witnessed the development of a number of alternative processes for enrichment. These processes, which are being studied and deployed around the world, offer a wide range of technical and economic characteristics which will be useful in assuring adequate capacity to meet projected reactor fuel market needs through the rest of this century at competitive prices. With present uncertainties in future enriched uranium needs, it is apparent that flexibility in the deployment and operation of any enrichment process will be one of the prime considerations for the future. More economical production of separative work not only can have a beneficial impact on reactor fuel costs, but also tends to conserve natural uranium resources. This paper reviews the world scene in the enrichment component of the fuel cycle, including existing or planned commercial-scale facilities and announced R and D efforts on various processes.

  13. Uranium enrichment: technology, economics, capacity

    International Nuclear Information System (INIS)

    Voigt, W.R. Jr.; Vanstrum, P.R.; Saire, D.E.; Gestson, D.K.; Peske, S.E.

    1982-01-01

    Large-scale enrichment of uranium has now been carried out for 40 years. While the gaseous diffusion process was the original choice of several countries and continues today to provide the major component of the world production of separative work, the last two decades have witnessed the development of a number of alternative processes for enrichment. These processes, which are being studied and deployed around the world, offer a wide range of technical and economic characteristics which will be useful in assuring adequate capacity to meet projected reactor fuel market needs through the rest of this century at competitive prices. With present uncertainties in future enriched uranium needs, it is apparent that flexibility in the deployment and operation of any enrichment process will be one of the prime considerations for the future. More economical production of separative work not only can have a beneficial impact on reactor fuel costs, but also tends to conserve natural uranium resources. This paper reviews the world scene in the enrichment component of the fuel cycle, including existing or planned commercial-scale facilities and announced R and D efforts on various processes

  14. Development of long-life low enrichment fuel

    International Nuclear Information System (INIS)

    Gietzen, A.J.; West, G.B.

    1978-01-01

    With only a few exceptions, TRIGA reactors have always used low-enriched-uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on non-proliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U. S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of this year, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with GA's standard commercial warranty

  15. Spatial and Temporal Patterns In Ecohydrological Separation

    Science.gov (United States)

    Jarvis, S. K.; Barnard, H. R.; Singha, K.; Harmon, R. E.; Szutu, D.

    2017-12-01

    The model of ecohydrological separation suggests that trees source water from a different subsurface pool than what is contributing to stream flow during dry periods, however diel fluctuations in stream flow and transpiration are tightly coupled. To better understand the mechanism of this coupling, this study examines spatiotemporal patterns in water isotopic relationships between tree, soil, and stream water. Preliminary analysis of data collected in 2015 show a trend in δ18O enrichment in xylem water, suggesting an increased reliance on enriched soil water not flowing to the stream as the growing season progresses, while xylem samples from 2016, a particularly wet year, do not have this trend. Variations in these temporal trends are explored with regard to distance from stream, aspect of hillslope, position in the watershed, size of the tree, and soil depth. Additionally, a near-stream site is examined at high resolution using water isotope data, sap flow, and electrical resistivity surveying to examine soil moisture and water use patterns across the riparian-hillslope transition.

  16. World enrichment requirements to 2005

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The primary enrichment suppliers-Eurodif, Techsnabexport, Urenco, and the US DOE - are positioning themselves to take advantage of the post - 1995 market. Overall, unfilled requirements represent about 40 percent of world requirements in the year 2000. The USA will be the primary market, as US utilities' unfilled enrichment requirements account for over 60 percent of the world's total unfilled requirements. The enrichment market is moving toward more global competition, as each supplier tries to maintain its current regional market base and then to capture additional market share in other regions

  17. DOE enrichment plants-safeguards means business

    International Nuclear Information System (INIS)

    Donnelly, R.

    1987-01-01

    The Portsmouth Gaseous Diffusion Plant, owned by the US Department of Energy (DOE) and operated by Martin Marietta Energy Systems, Inc., is a full service enrichment plant. Its long enriching cascade can process uranium hexafluoride (UF 6 ) feeds at almost any 235 U level and can produce UF 6 over the complete spectrum from depleted to very highly enriched uranium. The DOE uranium enrichment program is a government-owned enterprise operating as a business. The operating concerns of the DOE uranium enrichment plants and their safeguards programs have evolved together over the past three decades, and that evolution will likely continue. As the risk associated with possession, processing, and shipment of strategic nuclear material increased, the protection and control of it increased; as the value of the product grew with time, better ways were found to measure and conserve it. In each of these areas, safeguards objectives and the business requirements of the plant are complementary, and the progress made in one area has been reflected by progress in the other. The plant's material control and accountability program has become crucial to such business requirements as quantifying the enriched uranium (separative work units) produced in each monthly period and convincing financial auditors that the multibillion dollar enriched uranium assets located at the Portsmouth plant are properly stated

  18. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-08-01

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  19. Origin of middle rare earth element enrichments in acid waters of a Canadian high Arctic lake.

    Science.gov (United States)

    Johannesson, Kevin H.; Zhou, Xiaoping

    1999-01-01

    -Middle rare earth element (MREE) enriched rock-normalized rare earth element (REE) patterns of a dilute acidic lake (Colour Lake) in the Canadian High Arctic, were investigated by quantifying whole-rock REE concentrations of rock samples collected from the catchment basin, as well as determining the acid leachable REE fraction of these rocks. An aliquot of each rock sample was leached with 1 N HNO 3 to examine the readily leachable REE fraction of each rock, and an additional aliquot was leached with a 0.04 M NH 2OH · HCl in 25% (v/v) CH 3COOH solution, designed specifically to reduce Fe-Mn oxides/oxyhydroxides. Rare earth elements associated with the leachates that reacted with clastic sedimentary rock samples containing petrographically identifiable Fe-Mn oxide/oxyhydroxide cements and/or minerals/amorphous phases, exhibited whole-rock-normalized REE patterns similar to the lake waters, whereas whole-rock-normalized leachates from mafic igneous rocks and other clastic sedimentary rocks from the catchment basin differed substantially from the lake waters. The whole-rock, leachates, and lake water REE data support acid leaching or dissolution of MREE enriched Fe-Mn oxides/oxyhydroxides contained and identified within some of the catchment basin sedimentary rocks as the likely source of the unique lake water REE patterns. Solution complexation modelling of the REEs in the inflow streams and lake waters indicate that free metal ions (e.g., Ln 3+, where Ln = any REE) and sulfate complexes (LnSO 4+) are the dominant forms of dissolved REEs. Consequently, solution complexation reactions involving the REEs during weathering, transport to the lake, or within the lake, cannot be invoked to explain the MREE enrichments observed in the lake waters.

  20. Availability of enrichment services

    International Nuclear Information System (INIS)

    Svenke, E.

    1977-01-01

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increment in demand the timely need for enrichment capacity will be particularly sensitive to assumptions about growth rates. Existing worldwide capacity together with capacities under construction will be sufficient well into the 1980's. However, long decision and construction leadtime, uncertainty as to future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of increment. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, is requesting both long term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more cooperative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that request the highest degree of industrial processing of nuclear fuel, i.e. the compulsory enrichment of natural uranium, do not serve the interests of overall industrial efficiency

  1. Benchmarking methods and data sets for ligand enrichment assessment in virtual screening.

    Science.gov (United States)

    Xia, Jie; Tilahun, Ermias Lemma; Reid, Terry-Elinor; Zhang, Liangren; Wang, Xiang Simon

    2015-01-01

    Retrospective small-scale virtual screening (VS) based on benchmarking data sets has been widely used to estimate ligand enrichments of VS approaches in the prospective (i.e. real-world) efforts. However, the intrinsic differences of benchmarking sets to the real screening chemical libraries can cause biased assessment. Herein, we summarize the history of benchmarking methods as well as data sets and highlight three main types of biases found in benchmarking sets, i.e. "analogue bias", "artificial enrichment" and "false negative". In addition, we introduce our recent algorithm to build maximum-unbiased benchmarking sets applicable to both ligand-based and structure-based VS approaches, and its implementations to three important human histone deacetylases (HDACs) isoforms, i.e. HDAC1, HDAC6 and HDAC8. The leave-one-out cross-validation (LOO CV) demonstrates that the benchmarking sets built by our algorithm are maximum-unbiased as measured by property matching, ROC curves and AUCs. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Analysis of the performance of fuel cells PWR with a single enrichment and radial distribution of enrichments

    International Nuclear Information System (INIS)

    Vargas, S.; Gonzalez, J. A.; Alonso, G.; Del Valle, E.; Xolocostli M, J. V.

    2008-01-01

    One of the main challenges in the design of fuel assemblies is the efficient use of uranium achieving burnt homogeneous of the fuel rods as well as the burnt maximum possible of the same ones to the unload. In the case of the assemblies type PWR has been decided actually for fuel assemblies with a single radial enrichment. The present work has like effect to show the because of this decision, reason why a comparison of the neutronic performance of two fuel cells takes place with the same enrichment average but one of them with radial distribution of enrichment and the other with a single enrichment equal to the average. The results shown in the present study of the behavior of the neutron flow as well as the power distribution through of assembly sustain the because of a single radial enrichment. (Author)

  3. Civilian inventories of plutonium and highly enriched uranium

    International Nuclear Information System (INIS)

    Albright, D.

    1987-01-01

    In the future, commercial laser isotope enrichment technologies, currently under development, could make it easier for national to produce highly enriched uranium secretly. The head of a US firm that is developing a laser enrichment process predicts that in twenty years, major utilities and small countries will have relatively small, on-site, laser-based uranium enrichment facilities. Although these plants will be designed for the production of low enriched uranium, they could be modified to produce highly enriched uranium, an option that raises the possibility of countries producing highly enriched uranium in small, easily hidden facilities. Against this background, most of this report describes the current and future quantities of plutonium and highly enriched uranium in the world, their forms, the facilities in which they are produced, stored, and used, and the extent to which they are transported. 5 figures, 10 tables

  4. NRC licensing of uranium enrichment plants

    International Nuclear Information System (INIS)

    Moran, B.W.

    1991-01-01

    The US Nuclear Regulatory Commission (NRC) is preparing a rule making that establishes the licensing requirements for low-enriched uranium enrichment plants. Although implementation of this rule making is timed to correspond with receipt of a license application for the Louisiana Energy Services centrifuge enrichment plant, the rule making is applicable to all uranium enrichment technologies. If ownership of the US gaseous diffusion plants and/or atomic vapor laser isotope separation is transferred to a private or government corporation, these plants also would be licensable under the new rule making. The Safeguards Studies Department was tasked by the NRC to provide technical assistance in support of the rule making and guidance preparation process. The initial and primary effort of this task involved the characterization of the potential safeguards concerns associated with a commercial enrichment plant, and the licensing issues associated with these concerns. The primary safeguards considerations were identified as detection of the loss of special nuclear material, detection of unauthorized production of material of low strategic significance, and detection of production of uranium enriched to >10% 235 U. The primary safeguards concerns identified were (1) large absolute limit of error associated with the material balance closing, (2) the inability to shutdown some technologies to perform a cleanout inventory of the process system, and (3) the flexibility of some technologies to produce higher enrichments. Unauthorized production scenarios were identified for some technologies that could prevent conventional material control and accounting programs from detecting the production and removal of 5 kg 235 U as highly enriched uranium. Safeguards techniques were identified to mitigate these concerns

  5. Autoantigens targeted in scleroderma patients with vascular disease are enriched in endothelial lineage cells

    Science.gov (United States)

    McMahan, Zsuzsanna H.; Cottrell, Tricia R.; Wigley, Fredrick M.; Antiochos, Brendan; Zambidis, Elias T.; Park, Tea Soon; Halushka, Marc K.; Gutierrez-Alamillo, Laura; Cimbro, Raffaello; Rosen, Antony; Casciola-Rosen, Livia

    2016-01-01

    Objective Scleroderma patients with autoantibodies to centromere proteins (CENPs) and/or interferon-inducible protein 16 (IFI16) are at increased risk of severe vascular complications. We set out to define whether these autoantigens are enriched in cells of the vasculature. Methods Successive stages of embryoid bodies (EBs) as well as vascular progenitors were used to evaluate the expression of scleroderma autoantigens IFI16 and CENP by immunoblotting. CD31 was included to mark early blood vessels. IFI16 and CD31 expression were defined in skin paraffin sections from scleroderma patients and from healthy controls. IFI16 expression was determined by flow cytometry in circulating endothelial cells (CECs) and circulating progenitor cells (CPCs). Results Expression of CENP-A, IFI16 and CD31 was enriched in EBs at days 10 and 12 of differentiation, and particularly in cultures enriched in vascular progenitors (IFI16, CD31, CENPs A and-B). This pattern was distinct from that of comparator autoantigens. Immunohistochemical staining of skin paraffin sections showed enrichment of IFI16 in CD31-positive vascular endothelial cells in biopsies from scleroderma patients and normal controls. Flow cytometry analysis revealed IFI16 expression in CPCs, but minimal expression in CECs. Conclusion Expression of scleroderma autoantigens IFI16 and CENPs, which are associated with severe vascular disease, is increased in vascular progenitors and mature endothelial cells. High level, lineage-enriched expression of autoantigens may explain the striking association between clinical phenotypes and the immune targeting of specific autoantigens. PMID:27159521

  6. Environmental enrichment choices of shelter cats.

    Science.gov (United States)

    Ellis, J J; Stryhn, H; Spears, J; Cockram, M S

    2017-08-01

    Choices made by cats between different types of environmental enrichment may help shelters to prioritize how to most effectively enrich cat housing, especially when limited by space or funds. This study investigates the environmental enrichment use of cats in a choice test. Twenty-six shelter cats were kept singularly in choice chambers for 10days. Each chamber had a central area and four centrally-linked compartments containing different types of environmental enrichment: 1) an empty control, 2) a prey-simulating toy, 3) a perching opportunity, and 4) a hiding opportunity. Cat movement between compartments was quantitatively recorded using a data-logger. Enriched compartments were visited significantly more frequently during the light period than during the dark period. Cats spent a significantly greater percentage of time in the hiding compartment (median=55%, IQR=46) than in the toy compartment (median=2%, IQR=9), or in the empty control compartment (median=4%, IQR=4). These results provide additional evidence to support the value of a hiding box to cats housed in a novel environment, in that they choose hiding relative to other types of environmental enrichment. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weight Adults.

    Directory of Open Access Journals (Sweden)

    Ivy N Cheung

    Full Text Available Increasing evidence points to associations between light-dark exposure patterns, feeding behavior, and metabolism. This study aimed to determine the acute effects of 3 hours of morning versus evening blue-enriched light exposure compared to dim light on hunger, metabolic function, and physiological arousal. Nineteen healthy adults completed this 4-day inpatient protocol under dim light conditions (<20lux. Participants were randomized to 3 hours of blue-enriched light exposure on Day 3 starting either 0.5 hours after wake (n = 9; morning group or 10.5 hours after wake (n = 10; evening group. All participants remained in dim light on Day 2 to serve as their baseline. Subjective hunger and sleepiness scales were collected hourly. Blood was sampled at 30-minute intervals for 4 hours in association with the light exposure period for glucose, insulin, cortisol, leptin, and ghrelin. Homeostatic model assessment of insulin resistance (HOMA-IR and area under the curve (AUC for insulin, glucose, HOMA-IR and cortisol were calculated. Comparisons relative to baseline were done using t-tests and repeated measures ANOVAs. In both the morning and evening groups, insulin total area, HOMA-IR, and HOMA-IR AUC were increased and subjective sleepiness was reduced with blue-enriched light compared to dim light. The evening group, but not the morning group, had significantly higher glucose peak value during blue-enriched light exposure compared to dim light. There were no other significant differences between the morning or the evening groups in response to blue-enriched light exposure. Blue-enriched light exposure acutely alters glucose metabolism and sleepiness, however the mechanisms behind this relationship and its impacts on hunger and appetite regulation remain unclear. These results provide further support for a role of environmental light exposure in the regulation of metabolism.

  8. Complex temporal and spatial patterns in nonequilibrium processes

    International Nuclear Information System (INIS)

    Swinney, H.L.

    1992-01-01

    We have used dynamical systems methods to study and characterize bifurcations and pattern formation in a variety of nonequilibrium systems. In this paper we describe our work on dynamical systems, chemical oscillations and chaos, chemical spatial patterns, instabilities in fluid dynamics, electrodeposition clusters, the ballast resistor, and crack propagation

  9. Uranium enrichment: heading for a cliff

    International Nuclear Information System (INIS)

    Norman, C.

    1987-01-01

    Thanks to drastic cost cutting in the past 2 years, US enrichment plants now have the lowest cost production in the world, but US prices are still higher than those of overseas competitors because the business is paying for past mistakes. The most serious difficulty is that the Department of Energy (DOE), which owns and operates the US enrichment enterprise, is paying more than $500 million a year to the Tennessee Valley Authority (TVA) for electricity it once thought it would need but no longer requires. Another is that billions of dollars were spent in the 1970s and early 1980s to build new capacity that is now not needed. As a result, the enrichment enterprise has accumulated a debt to the US Treasury that the General Accounting Office (GAO) estimates at $8.8 billion. This paper presents the background and current debate in Congress about the difficulties facing the enrichment industry. In the midst of this debate over the future of the enterprise, the development of the next generation of enrichment technology is being placed in jeopardy. Known as atomic vapor laser isotope separation, or AVLIS, the process was viewed as the key to the long-term competitiveness of US enrichment. As the federal deficit mounted, however, funding for the AVLIS program was cut back and the timetable was stretched out. The US enrichment program has reached the point at which Congress will be forced to make some politically difficult decisions

  10. Safety of uranium enrichment plant

    International Nuclear Information System (INIS)

    Yonekawa, Shigeru; Morikami, Yoshio; Morita, Minoru; Takahashi, Tsukasa; Tokuyasu, Takashi.

    1991-01-01

    With respect to safety evaluation of the gas centrifuge enrichment facility, several characteristic problems are described as follows. Criticality safety in the cascade equipments can be obtained to maintain the enrichment of UF 6 below 5 %. External radiation dose equivalent rate of the 30B cylinder is low enough, the shield is not necessary. Penetration ratio of the two-stage HEPA filters for UF 6 aerosol is estimated at 10 -9 . From the experimental investigation, vacuum tightness is not damaged by destruction of gas centrifuge rotor. Carbon steel can be used for uranium enrichment equipments under the condition below 100degC. (author)

  11. Profile of World Uranium Enrichment Programs - 2007

    International Nuclear Information System (INIS)

    Laughter, Mark D.

    2007-01-01

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring weapons grade fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, while HEU is produced using a uranium enrichment process. Enrichment is also an important step in the civil nuclear fuel cycle, in producing low enriched uranium (LEU) for use in fuel for nuclear reactors. However, the same equipment used to produce LEU for nuclear fuel can also be used to produce HEU for weapons. Safeguards at an enrichment plant are the array of assurances and verification techniques that ensure uranium is only enriched to LEU, no undeclared LEU is produced, and no uranium is enriched to HEU or secretly diverted. There are several techniques for enriching uranium. The two most prevalent are gaseous diffusion, which uses older technology and requires a lot of energy, and gas centrifuge separation, which uses more advanced technology and is more energy efficient. Gaseous diffusion plants (GDPs) provide about 40% of current world enrichment capacity, but are being phased out as newer gas centrifuge enrichment plants (GCEPs) are constructed. Estimates of current and future enrichment capacity are always approximate, due to the constant upgrades, expansions, and shutdowns occurring at enrichment plants, largely determined by economic interests. Currently, the world enrichment capacity is approximately 53 million kg-separative work units (SWU) per year, with 22 million in gaseous diffusion and 31 million in gas centrifuge plants. Another 23 million SWU/year of capacity are under construction or planned for the near future, almost entirely using gas centrifuge separation. Other less-efficient techniques have also been used in the past, including electromagnetic and aerodynamic separations, but these are considered obsolete, at least from a commercial perspective. Laser isotope separation shows promise as a possible enrichment technique

  12. Detection of Group B Streptococcus in Brazilian pregnant women and antimicrobial susceptibility patterns

    Directory of Open Access Journals (Sweden)

    Didier Silveira Castellano-Filho

    2010-12-01

    Full Text Available Group B Streptococcus (GBS is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5% of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6% specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7% were resistant to erythromycin and 50% were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.

  13. Atom interaction propensities of oxygenated chemical functions in crystal packings

    Directory of Open Access Journals (Sweden)

    Christian Jelsch

    2017-03-01

    Full Text Available The crystal contacts of several families of hydrocarbon compounds substituted with one or several types of oxygenated chemical groups were analyzed statistically using the Hirshfeld surface methodology. The propensity of contacts to occur between two chemical types is described with the contact enrichment descriptor. The systematic large enrichment ratios of some interactions like the O—H...O hydrogen bonds suggests that these contacts are a driving force in the crystal packing formation. The same statement holds for the weaker C—H...O hydrogen bonds in ethers, esters and ketones, in the absence of polar H atoms. The over-represented contacts in crystals of oxygenated hydrocarbons are generally of two types: electrostatic attractions (hydrogen bonds and hydrophobic interactions. While Cl...O interactions are generally avoided, in a minority of chloro-oxygenated hydrocarbons, significant halogen bonding does occur. General tendencies can often be derived for many contact types, but outlier compounds are instructive as they display peculiar or rare features. The methodology also allows the detection of outliers which can be structures with errors. For instance, a significant number of hydroxylated molecules displaying over-represented non-favorable oxygen–oxygen contacts turned out to have wrongly oriented hydroxyl groups. Beyond crystal packings with a single molecule in the asymmetric unit, the behavior of water in monohydrate compounds and of crystals with Z′ = 2 (dimers are also investigated. It was found in several cases that, in the presence of several oxygenated chemical groups, cross-interactions between different chemical groups (e.g. water/alcohols; alcohols/phenols are often favored in the crystal packings. While some trends in accordance with common chemical principles are retrieved, some unexpected results can however appear. For example, in crystals of alcohol–phenol compounds, the strong O—H...O hydrogen bonds between

  14. Enriched but not depleted uranium affects central nervous system in long-term exposed rat.

    Science.gov (United States)

    Houpert, Pascale; Lestaevel, Philippe; Bussy, Cyrill; Paquet, François; Gourmelon, Patrick

    2005-12-01

    Uranium is well known to induce chemical toxicity in kidneys, but several other target organs, such as central nervous system, could be also affected. Thus in the present study, the effects on sleep-wake cycle and behavior were studied after chronic oral exposure to enriched or depleted uranium. Rats exposed to 4% enriched uranium for 1.5 months through drinking water, accumulated twice as much uranium in some key areas such as the hippocampus, hypothalamus and adrenals than did control rats. This accumulation was correlated with an increase of about 38% of the amount of paradoxical sleep, a reduction of their spatial working memory capacities and an increase in their anxiety. Exposure to depleted uranium for 1.5 months did not induce these effects, suggesting that the radiological activity induces the primary events of these effects of uranium.

  15. The future cost of uranium enrichment

    International Nuclear Information System (INIS)

    Pouris, A.

    1986-01-01

    The cost of uranium enrichment is the most important factor determining the fuel cost of nuclear energy. This paper attempts to forecast the future direction of the price of separative work by examining the forces that determine it. It is argued that the interplay among the characteristics of enrichment technologies, the structure of the international market, and the balance of supply and demand determine the enrichment price. The analysis indicates that all forces point towards a price much lower than the current one. It is predicted that, depending on the technological advances, the price of separative work unit for uranium enrichment will range between $40 and $90 by the year 2000. (author)

  16. 31 CFR 540.308 - Low Enriched Uranium (LEU).

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Low Enriched Uranium (LEU). 540.308... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.308 Low Enriched Uranium (LEU). The term low enriched...

  17. Enrichment and desalting of tryptic protein digests and the protein depletion using boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Fischnaller, Martin; Köck, Rainer; Bakry, Rania, E-mail: rania.bakry@uibk.ac.at; Bonn, Günther K.

    2014-05-01

    Highlights: • Protein tryptic digests were desalted and enriched utilizing hexagonal boron nitride. • Phosphopeptides were desalted with high recovery rates. • Boron nitride exhibits high wettability allowing fast sample preparation. • Boron nitride shows protein depletion capability applied for peptide purification. - Abstract: Sample preparation still remains a great challenge in modern bioanalysis and the interest in new efficient solid phase extraction (SPE) materials still remains high. In this work, hexagonal boron nitride (h-BN) is introduced as a new SPE material for the isolation and enrichment of peptides. The h-BN is isoelectronic and structurally similar to graphite. It has remarkable properties including good thermal conductivity, excellent thermal and chemical stability and a better oxidation resistance than graphite. BN attracts increasing interest because of its wide range of applicability. In the present work, the great potential of h-BN, as a new SPE-material, on the enrichment, preconcentration and desalting of tryptic digest of model proteins is demonstrated. A special attention was dedicated to the efficient enrichment of hydrophilic phosphopeptides. Two elution protocols were developed for the enrichment of peptides compatible for subsequent MALDI-MS and ESI-MS analysis. In addition, the recoveries of 5 peptides and 3 phosphopeptides with wide range of pI values utilizing h-BN materials with different surface areas were investigated. 84–106% recovery rate could be achieved using h-BN materials. The results were compared with those obtained using graphite and silica C18 under the same elution conditions, and lower recoveries were obtained. In addition, h-BN was found to have a capability of protein depletion, which is requisite for the peptide profiling.

  18. Enrichment and desalting of tryptic protein digests and the protein depletion using boron nitride

    International Nuclear Information System (INIS)

    Fischnaller, Martin; Köck, Rainer; Bakry, Rania; Bonn, Günther K.

    2014-01-01

    Highlights: • Protein tryptic digests were desalted and enriched utilizing hexagonal boron nitride. • Phosphopeptides were desalted with high recovery rates. • Boron nitride exhibits high wettability allowing fast sample preparation. • Boron nitride shows protein depletion capability applied for peptide purification. - Abstract: Sample preparation still remains a great challenge in modern bioanalysis and the interest in new efficient solid phase extraction (SPE) materials still remains high. In this work, hexagonal boron nitride (h-BN) is introduced as a new SPE material for the isolation and enrichment of peptides. The h-BN is isoelectronic and structurally similar to graphite. It has remarkable properties including good thermal conductivity, excellent thermal and chemical stability and a better oxidation resistance than graphite. BN attracts increasing interest because of its wide range of applicability. In the present work, the great potential of h-BN, as a new SPE-material, on the enrichment, preconcentration and desalting of tryptic digest of model proteins is demonstrated. A special attention was dedicated to the efficient enrichment of hydrophilic phosphopeptides. Two elution protocols were developed for the enrichment of peptides compatible for subsequent MALDI-MS and ESI-MS analysis. In addition, the recoveries of 5 peptides and 3 phosphopeptides with wide range of pI values utilizing h-BN materials with different surface areas were investigated. 84–106% recovery rate could be achieved using h-BN materials. The results were compared with those obtained using graphite and silica C18 under the same elution conditions, and lower recoveries were obtained. In addition, h-BN was found to have a capability of protein depletion, which is requisite for the peptide profiling

  19. Polycrystalline thin films of antimony selenide via chemical bath deposition and post deposition treatments

    International Nuclear Information System (INIS)

    Rodriguez-Lazcano, Y.; Pena, Yolanda; Nair, M.T.S.; Nair, P.K.

    2005-01-01

    We report a method for obtaining thin films of polycrystalline antimony selenide via chemical bath deposition followed by heating the thin films at 573 K in selenium vapor. The thin films deposited from chemical baths containing one or more soluble complexes of antimony, and selenosulfate initially did not show X-ray diffraction (XRD) patterns corresponding to crystalline antimony selenide. Composition of the films, studied by energy dispersive X-ray analyses indicated selenium deficiency. Heating these films in presence of selenium vapor at 573 K under nitrogen (2000 mTorr) resulted in an enrichment of Se in the films. XRD peaks of such films matched Sb 2 Se 3 . Evaluation of band gap from optical spectra of such films shows absorption due to indirect transition occurring in the range of 1-1.2 eV. The films are photosensitive, with dark conductivity of about 2 x 10 -8 (Ω cm) -1 and photoconductivity, about 10 -6 (Ω cm) -1 under tungsten halogen lamp illumination with intensity of 700 W m -2 . An estimate for the mobility life time product for the film is 4 x 10 -9 cm 2 V -1

  20. Enrichment of Zinc in Galactic Chemodynamical Evolution Models

    Science.gov (United States)

    Hirai, Yutaka; Saitoh, Takayuki R.; Ishimaru, Yuhri; Wanajo, Shinya

    2018-03-01

    The heaviest iron-peak element Zinc (Zn) has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show an increasing trend of [Zn/Fe] ratios toward lower metallicity. However, the enrichment of Zn in galaxies is not well understood due to poor knowledge of astrophysical sites of Zn, as well as metal mixing in galaxies. Here we show possible explanations for the observed trend by taking into account electron-capture supernovae (ECSNe) as one of the sources of Zn in our chemodynamical simulations of dwarf galaxies. We find that the ejecta from ECSNe contribute to stars with [Zn/Fe] ≳ 0.5. We also find that scatters of [Zn/Fe] in higher metallicities originate from the ejecta of type Ia supernovae. On the other hand, it appears difficult to explain the observed trends if we do not consider ECSNe as a source of Zn. These results come from an inhomogeneous spatial metallicity distribution due to the inefficiency of the metal mixing. We find that the optimal value of the scaling factor for the metal diffusion coefficient is ∼0.01 in the shear-based metal mixing model in smoothed particle hydrodynamics simulations. These results suggest that ECSNe could be one of the contributors of the enrichment of Zn in galaxies.

  1. Bioactive compounds from orange epicarp to enrich fish burgers.

    Science.gov (United States)

    Spinelli, Sara; Lecce, Lucia; Likyova, Desislava; Del Nobile, Matteo Alessandro; Conte, Amalia

    2018-05-01

    The orange industry produces considerable amounts of by-products, traditionally used for animal feed or fuel production. Most of these by-products could be used as functional ingredients. To assess the potential food application of orange epicarp, different percentages of micro-encapsulated orange extract were added to fresh fish burgers. Then, an in vitro digestion was also carried out, before and after micro-encapsulation, to measure the bio-accessibility of the active compounds. A significant increase of bio-accessibility of bioactive compounds has been observed in the orange epicarp extract after micro-encapsulation by spray-drying. From the sensory point of view, the fish sample enriched with 50 g kg -1 micro-encapsulated extract was the most comparable to the control burger, even if it showed a higher phenolic, flavonoid and carotenoid bio-accessibility. Orange epicarp may be used as a food additive to enhance the health content of food products. The micro-encapsulation is a valid technique to protect the bioactive compounds and increase their bio-accessibility. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  2. Industrial aspects in uranium enrichment

    International Nuclear Information System (INIS)

    Mezin, M.

    1982-05-01

    Characteristics of isotope separation processes in operation and under development are discussed. These include the number of stages in series, the number of components, the component unit capacity and enery requirements. The implementation of an enrichment process and the question of an enrichment plant in Australia are also considered

  3. Stripping voltammetric behavior of technetium at various chemically modified electrodes

    International Nuclear Information System (INIS)

    Dick, R.

    1990-09-01

    In monitoring of nuclear processing plants and storage facilities the necessity arises of assaying traces of the artificial radioactive element technetium. The oxidation states IV and VII are of particular interest. Stripping voltammetry is among the methods of assay which are suited for this purpose. It allows an enhanced selectivity to be achieved by preconcentration of the analyte and of an oxidation state of the analyte, respectively, at the electrode used. This specific enrichment is successful after appropriate chemical modification of the electrode through immobilization of a Tc-specific reagent. When various approaches of chemical modification of a glassy carbon electrode were examined, the tetraphenylarsonium chloride extractant, which is highly selective with respect to technetium, proved to be the best suited reagent, capable of fixation both by ionic and by covalent bonding on an electrodeposited polymer film. For ionic immobilization the reagent was reacted to m-sulfophenyltriphenyl arsonium and then bound to a copolymer of vinylferrocene and vinylpyridine, which had been provided with cations. It was possible to enrich Tc(VII) at such an electrode and to determine it by stripping voltammetry down to a concentration of 1x10 -8 M after 5 minutes enrichment time. (orig./EF) [de

  4. Chemical and olfactometric characterization of volatile flavor compounds in a fish oil enriched milk emulsion

    DEFF Research Database (Denmark)

    Venkateshwarlu Venkat, Guidipati; Bruni Let, Mette; Meyer, Anne S.

    2004-01-01

    cold storage (2 degreesC) for 14 days by dynamic headspace sampling followed by gas chromatography-mass spectrometry analyses. Different volatiles (n = 60) comprising alkenals, alkadienals, alkatrienals, and vinyl ketones were identified in the fish oil enriched milk. The potent odorants identified...... by gas chromatography-olfactometry were 1-penten-3-one, (Z)-4-heptenal, 1-octen-3-one, (Z)-1,5-octadien-3-one, (E,E)-2,4-heptadienal, and (E,Z)-2,6-nonadienal, but despite their potency, none of the separated volatiles imparted a fishy or metallic odor. Two isomers, (E,Z,Z) and (E,E,Z) of 2...

  5. APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy

    International Nuclear Information System (INIS)

    Hasselquist, Sten; Holtzman, Jon; Shetrone, Matthew; Smith, Verne; Nidever, David L.; McWilliam, Andrew; Fernández-Trincado, J. G.; Tang, Baitian; Beers, Timothy C.; Majewski, Steven R.; Anguiano, Borja; Tissera, Patricia B.; Alvar, Emma Fernández; Carigi, Leticia; Delgado Inglada, Gloria; Allende Prieto, Carlos; Battaglia, Giuseppina; García-Hernández, D. A.; Almeida, Andres; Frinchaboy, Peter

    2017-01-01

    The Apache Point Observatory Galactic Evolution Experiment provides the opportunity of measuring elemental abundances for C, N, O, Na, Mg, Al, Si, P, K, Ca, V, Cr, Mn, Fe, Co, and Ni in vast numbers of stars. We analyze thechemical-abundance patterns of these elements for 158 red giant stars belonging to the Sagittarius dwarf galaxy (Sgr). This is the largest sample of Sgr stars with detailed chemical abundances, and it is the first time that C, N, P, K, V, Cr, Co, and Ni have been studied at high resolution in this galaxy. We find that the Sgr stars with [Fe/H] ≳ −0.8 are deficient in all elemental abundance ratios (expressed as [X/Fe]) relative to the Milky Way, suggesting that the Sgr stars observed today were formed from gas that was less enriched by Type II SNe than stars formed in the Milky Way. By examining the relative deficiencies of the hydrostatic (O, Na, Mg, and Al) and explosive (Si, P, K, and Mn) elements, our analysis supports the argument that previous generations of Sgr stars were formed with a top-light initial mass function, one lacking the most massive stars that would normally pollute the interstellar medium with the hydrostatic elements. We use a simple chemical-evolution model, flexCE, to further support our claim and conclude that recent stellar generations of Fornax and the Large Magellanic Cloud could also have formed according to a top-light initial mass function.

  6. APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hasselquist, Sten; Holtzman, Jon [New Mexico State University, Las Cruces, NM 88003 (United States); Shetrone, Matthew [University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734 (United States); Smith, Verne; Nidever, David L. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); McWilliam, Andrew [The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Fernández-Trincado, J. G.; Tang, Baitian [Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Concepción (Chile); Beers, Timothy C. [Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States); Majewski, Steven R.; Anguiano, Borja [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Tissera, Patricia B. [Department of Physics, Universidad Andres Bello, 700 Fernandez Concha (Chile); Alvar, Emma Fernández; Carigi, Leticia; Delgado Inglada, Gloria [Instituto de Astronomía, Universidad Nacional Autnoma de México, Apdo. Postal 70264, Ciudad de México, 04510 (Mexico); Allende Prieto, Carlos; Battaglia, Giuseppina; García-Hernández, D. A. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Almeida, Andres [Departamento de Física, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena (Chile); Frinchaboy, Peter, E-mail: sten@nmsu.edu, E-mail: holtz@nmsu.edu, E-mail: shetrone@astro.as.utexas.edu, E-mail: vsmith@email.noao.edu [Texas Christian University, Fort Worth, TX 76129 (United States); and others

    2017-08-20

    The Apache Point Observatory Galactic Evolution Experiment provides the opportunity of measuring elemental abundances for C, N, O, Na, Mg, Al, Si, P, K, Ca, V, Cr, Mn, Fe, Co, and Ni in vast numbers of stars. We analyze thechemical-abundance patterns of these elements for 158 red giant stars belonging to the Sagittarius dwarf galaxy (Sgr). This is the largest sample of Sgr stars with detailed chemical abundances, and it is the first time that C, N, P, K, V, Cr, Co, and Ni have been studied at high resolution in this galaxy. We find that the Sgr stars with [Fe/H] ≳ −0.8 are deficient in all elemental abundance ratios (expressed as [X/Fe]) relative to the Milky Way, suggesting that the Sgr stars observed today were formed from gas that was less enriched by Type II SNe than stars formed in the Milky Way. By examining the relative deficiencies of the hydrostatic (O, Na, Mg, and Al) and explosive (Si, P, K, and Mn) elements, our analysis supports the argument that previous generations of Sgr stars were formed with a top-light initial mass function, one lacking the most massive stars that would normally pollute the interstellar medium with the hydrostatic elements. We use a simple chemical-evolution model, flexCE, to further support our claim and conclude that recent stellar generations of Fornax and the Large Magellanic Cloud could also have formed according to a top-light initial mass function.

  7. Advances in uranium enrichment processes

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.; Slater, J.B.

    1986-05-01

    Advances in gas centrifuges and development of the atomic vapour laser isotope separation process promise substantial reductions in the cost of enriched uranium. The resulting reduction in LWR fuel costs could seriously erode the economic advantage of CANDU, and in combination with LWR design improvements, shortened construction times and increased operational reliability could allow the LWR to overtake CANDU. CANDU's traditional advantages of neutron economy and high reliability may no longer be sufficient - this is the challenge. The responses include: combining neutron economy and dollar economy by optimizing CANDU for slightly enriched uranium fuel; developing cost-reducing improvements in design, manufacture and construction; and reducing the cost of heavy water. Technology is a renewable resource which must be continually applied to a product for it to remain competitive in the decades to come. Such innovation is a prerequisite to Canada increasing her share of the international market for nuclear power stations. The higher burn-up achievable with enriched fuel in CANDU can reduce the fuel cycle costs by 20 to 40 percent for a likely range of costs for yellowcake and separative work. Alternatively, some of the benefits of a higher fissile content can take the form of a cheaper reactor core containing fewer fuel channels and less heavy water, and needing only a single fuelling machine. An opportunity that is linked to this need to introduce an enriched uranium fuel cycle into CANDU is to build an enrichment business in Canada. This could offer greater value added to our uranium exports, security of supply for enriched CANDUs, technological growth in Canada and new employment opportunities. AECL has a study in progress to define this opportunity

  8. Aptamer based peptide enrichment for quantitative analysis of gonadotropin-releasing hormone by LC-MS/MS.

    Science.gov (United States)

    Richards, S L; Cawley, A T; Cavicchioli, R; Suann, C J; Pickford, R; Raftery, M J

    2016-04-01

    Over recent years threats to racing have expanded to include naturally occurring biological molecules, such as peptides and proteins, and their synthetic analogues. Traditionally, antibodies have been used to enable detection of these compounds as they allow purification and concentration of the analyte of interest. The rapid expansion of peptide-based therapeutics necessitates a similarly rapid development of suitable antibodies or other means of enrichment. Potential alternative enrichment strategies include the use of aptamers, which offer the significant advantage of chemical synthesis once the nucleic acid sequence is known. A method was developed for the enrichment, detection and quantitation of gonadotropin-releasing hormone (GnRH) in equine urine using aptamer-based enrichment and LC-MS/MS. The method achieved comparable limits of detection (1 pg/mL) and quantification (2.5 pg/mL) to previously published antibody-based enrichment methods. The intra- and inter-assay precision achieved was less than 10% at both 5 and 20 pg/mL, and displayed a working dynamic range of 2.5-100 pg/mL. Significant matrix enhancement (170 ± 8%) and low analytical recovery (29 ± 15%) was observed, although the use of an isotopically heavy labelled GnRH peptide, GnRH (Pro(13)C5,(15)N), as the internal standard provides compensation for these parameters. Within the current limits of detection GnRH was detectable up to 1h post administration in urine and identification of a urinary catabolite extended this detection window to 4h. Based on the results of this preliminary investigation we propose the use of aptamers as a viable alternative to antibodies in the enrichment of peptide targets from equine urine. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Low-enriched uranium high-density target project. Compendium report

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, George; Brown, M. Alex; Jerden, James L.; Gelis, Artem V.; Stepinski, Dominique C.; Wiedmeyer, Stanley; Youker, Amanda; Hebden, Andrew; Solbrekken, G; Allen, C; Robertson., D; El-Gizawy, Sherif; Govindarajan, Srisharan; Hoyer, Annemarie; Makarewicz, Philip; Harris, Jacob; Graybill, Brian; Gunn, Andy; Berlin, James; Bryan, Chris; Sherman, Steven; Hobbs, Randy; Griffin, F. P.; Chandler, David; Hurt, C. J.; Williams, Paul; Creasy, John; Tjader, Barak; McFall, Danielle; Longmire, Hollie

    2016-09-01

    At present, most 99Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 µm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world’s supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassembly of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration.

  10. Repository emplacement costs for Al-clad high enriched uranium spent fuel

    International Nuclear Information System (INIS)

    McDonell, W.R.; Parks, P.B.

    1994-01-01

    A range of strategies for treatment and packaging of Al-clad high-enriched uranium (HEU) spent fuels to prevent or delay the onset of criticality in a geologic repository was evaluated in terms of the number of canisters produced and associated repository costs incurred. The results indicated that strategies in which neutron poisons were added to consolidated forms of the U-Al alloy fuel generally produced the lowest number of canisters and associated repository costs. Chemical processing whereby the HEU was removed from the waste form was also a low cost option. The repository costs generally increased for isotopic dilution strategies, because of the substantial depleted uranium added. Chemical dissolution strategies without HEU removal were also penalized because of the inert constituents in the final waste glass form. Avoiding repository criticality by limiting the fissile mass content of each canister incurred the highest repository costs

  11. Chemical toxicity and radiological health detriment associated with the inhalation of various enrichments of uranium

    International Nuclear Information System (INIS)

    3C Limited, Queen Square House, 18-21 Queen Square, Bristol BS1 4NH (United Kingdom))" data-affiliation=" (SR3C Limited, Queen Square House, 18-21 Queen Square, Bristol BS1 4NH (United Kingdom))" >Bryant, P A

    2014-01-01

    The occupational risks associated with the chemical toxicity of uranium can be overlooked during the processing, handling and storage of the material, as the radioactivity of the material is often used alone to assess the health consequences of exposure to uranium compounds. This note provides a summary of the current United Kingdom occupational standards for uranium based on radiation dose and/or chemical toxicity with a particular focus on intake via inhalation. A simple model is subsequently presented to allow a comparison to be drawn between the occupational exposure standard for chemical toxicity and radiological dose limit. Using these data a set of suggested limits on occupational exposure to airborne uranium is proposed that indicate where the legal annual radiological dose limit for workers or the Health and Safety Executive occupational exposure standard for chemical toxicity are at risk of being breached. (note)

  12. Environmental enrichment for aquatic animals.

    Science.gov (United States)

    Corcoran, Mike

    2015-05-01

    Aquatic animals are the most popular pets in the United States based on the number of owned pets. They are popular display animals and are increasingly used in research settings. Enrichment of captive animals is an important element of zoo and laboratory medicine. The importance of enrichment for aquatic animals has been slower in implementation. For a long time, there was debate over whether or not fish were able to experience pain or form long-term memories. As that debate has reduced and the consciousness of more aquatic animals is accepted, the need to discuss enrichment for these animals has increased. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Nitrogen-enriched bituminous coal-based active carbons as materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    R. Pietrzak; K. Jurewicz; P. Nowicki; K. Babel; H. Wachowska [A. Mickiewicz University, Poznan (Poland). Laboratory of Coal Chemistry and Technology

    2010-11-15

    The paper presents the results of a study on obtaining N-enriched active carbons from bituminous coal and on testing its use as an electrode material in supercapacitors. The coal was carbonised, activated with KOH and ammoxidised by a mixture of ammonia and air at the ratio 1:3 at 300{sup o}C or 350{sup o}C, at different stages of the production, that is, at those of precursor, carbonisate, and active carbon. The products were microporous N-enriched active carbon samples of well-developed surface area reaching from 1577 to 2510 m{sup 2}/g and containing 1.0 to 8.5 wt% of nitrogen. The XPS measurements have shown that in the active carbons enriched in nitrogen at the stage of precursor and at the stage of carbonisate, the dominant nitrogen species are the N-5 groups, while in the samples ammoxidised at the last stage of the treatment the dominant nitrogen species are the surface groups of imines and/or nitriles, probably accompanied by amines and amides. The paper reports the results of a comprehensive study of the effect of the structure and chemical composition of a series of active carbon samples of different properties on their capacity performance in water solutions of H{sub 2}SO{sub 4} or KOH, with the behaviour of positive and negative electrodes analysed separately. 33 refs., 7 figs., 8 tabs.

  14. The global chemical systematics of arc front stratovolcanoes: Evaluating the role of crustal processes

    Science.gov (United States)

    Turner, Stephen J.; Langmuir, Charles H.

    2015-07-01

    Petrogenetic models for convergent margins should be consistent with the global systematics of convergent margin volcanic compositions. A newly developed tool for compiling and screening data from the GEOROC database was used to generate a global dataset of whole rock chemical analyses from arc front stratovolcano samples. Data from 227 volcanoes within 31 volcanic arc segments were first averaged by volcano and then by arc to explore global systematics. Three different methods of data normalization produce consistent results that persist across a wide range of Mg# [Mg# =Mg / (Mg +Fe) ]. Remarkably coherent systematics are present among major and trace element concentrations and ratios, with the exception of three arcs influenced by mantle plumes and Peru/N. Chile, which is built on exceptionally thick crust. Chemical parameters also correlate with the thickness of the overlying arc crust. In addition to previously established correlations of Na6.0 with Ca6.0 and crustal thickness, correlations are observed among major elements, trace elements, and trace element ratios (e.g. La/Yb, Dy/Yb, Zr/Sm, Zr/Ti). Positive correlations include "fluid mobile," "high field strength," and "large ion lithophile" element groups, with concentrations that vary by a factor of five in all groups. Incompatible element enrichments also correlate well with crustal thickness, with the greatest enrichment found at arcs with the thickest crust. Intra-crustal processes, however, do not reproduce the global variations. High pressure fractionation produces intermediate magmas enriched in aluminum, but such magmas are rare. Furthermore, differences among magma compositions at various volcanic arcs persist from primitive to evolved compositions, which is inconsistent with the possibility that global variations are produced by crystal fractionation at any pressure. Linear relationships among elements appear to be consistent with mixing between depleted primary magma and an enriched contaminant

  15. Modelling Chemical Patterns of Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) in the Iberian Peninsula

    Science.gov (United States)

    Ratola, Nuno; Jiménez-Guerrero, Pedro

    2013-04-01

    Semi-volatile organic compounds (SVOCs) such as PBDEs, PCBs, organochlorine pesticides (OCPs) or PAHs, are widespread and generated in a multitude of anthropogenic (and natural for PAHs) processes and although they are found in the environment at low concentrations, possess an extraordinary carcinogenic capacity (Baussant et al., 2001) and high ecotoxicity due to their persistence in different matrices (air, soil, water, living organisms). In particular, PAHs are originated by combustion processes or release from fossil fuels and can be transported in the atmosphere over long distances in gaseous or particulate matter (Baek et al., 1991). The establishment of strategies for sampling and chemical transport modelling of SVOCs in the atmosphere aiming the definition and validation of the spatial, temporal and chemical transport patterns of contaminants can be achieved by an integrated system of third-generation models that represent the current state of knowledge in air quality modelling and experimental data collected in field campaigns. This has implications in the fields of meteorology, atmospheric chemistry and even climate change. In this case, an extensive database already obtained on levels of atmospheric PAHs from biomonitoring schemes in the Iberian Peninsula fuelled the establishment of the first models of behaviour for PAHs. The modelling system WRF+CHIMERE was implemented with high spatial and temporal resolution to the Iberian Peninsula in this first task (9 km for the Iberian Peninsula, 3 km to Portugal, 1 hour), using PAHs atmospheric levels collected over a year-long sampling scheme comprising 4 campaigns (one per season) in over 30 sites. Daily information on meteorological parameters such as air temperature, humidity, rainfall or wind speed and direction was collected from the weather stations closest to the sampling sites. Diagnosis and forecasts of these meteorological variables using MM5 or WRF were used to feed a chemistry transport model

  16. Characterization of Porous Phosphate Coatings Enriched with Magnesium or Zinc on CP Titanium Grade 2 under DC Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Krzysztof Rokosz

    2018-02-01

    Full Text Available The aim of the paper is to study and determine the effect of voltage increasing from 500 up to 650 VDC on chemical and electrochemical properties of the obtained porous coatings with plasma electrolytic oxidation (PEO processes, known also as micro arc oxidation (MAO. In the present paper, the chemical and electrochemical characterization of porous phosphate coatings enriched with magnesium or zinc on commercially pure (CP Titanium Grade 2 under DC-PEO obtained in electrolytes based on concentrated 85% analytically pure H3PO4 (98 g/mole acid with additions of 500 g·L−1 of zinc nitrate Zn(NO32∙6H2O or magnesium nitrate Mg(NO32∙6H2O, are described. These materials were characterized using scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDS, X-ray photoelectron spectroscopy (XPS and glow discharge optical emission spectroscopy (GDOES. It was found that the voltage of PEO process has influence on the chemical composition and thickness of the obtained porous coatings as well as on their electrochemical behavior. The higher the potential of PEO treatment, the higher the amount of zinc-to-phosphorus ratio for zinc enriched coatings was obtained, whereas in magnesium enriched coatings, the average amount of magnesium detected in PEO coating is approximately independent of the PEO voltages. Based on XPS studies, it was found out that most likely the top 10 nm of porous coatings is constructed of titanium (Ti4+, magnesium (Mg2+, zinc (Zn2+, and phosphates PO43− and/or HPO42− and/or H2PO4− and/or P2O74−. On the basis of GDOES studies, a four-sub-layer model of PEO coatings is proposed. Analysis of the potentiodynamic corrosion curves allowed to conclude that the best electrochemical repeatability was noted for magnesium and zinc enriched coatings obtained at 575 VDC.

  17. Review of uranium enrichment prospects in Canada, 1976

    International Nuclear Information System (INIS)

    Developments since 1971 which affect the prospects for uranium enrichment in Canada from the federal government point of view are reviewed. The market for enriched uranium to the year 2000 is similar to that projected in 1971. The committed enrichment capacity of the world will be sufficient until 1990. The Canadian uranium mining capability may be adequate to supply an enrichment plant, but the present reserves policy along with the currently known resources are likely to restrict exports of its products during the plant life. Prices for enriched uranium produced in Canada would be higher than those reported by other proposed new plants; however, newer enrichment techniques have some potential for cost reductions. Application of enrichment with U235 (or plutonium and U233/thorium) to CANDU offers some uranium resource conservation and possible slight power cost reductions. Construction of an enrichment plant in Canada to supply the export market is less attractive in 1976 than in 1971, but there is potential for such a business in the future. (L.L.)

  18. Profile of World Uranium Enrichment Programs-2009

    International Nuclear Information System (INIS)

    Laughter, Mark D.

    2009-01-01

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, whereas HEU is produced using a uranium enrichment process. Enrichment is also an important step in the civil nuclear fuel cycle, in producing low enriched uranium (LEU) for use as fuel for nuclear reactors to generate electricity. However, the same equipment used to produce LEU for nuclear reactor fuel can also be used to produce HEU for weapons. Safeguards at an enrichment plant are the array of assurances and verification techniques that ensure uranium is not diverted or enriched to HEU. There are several techniques for enriching uranium. The two most prevalent are gaseous diffusion, which uses older technology and requires a lot of energy, and gas centrifuge separation, which uses more advanced technology and is more energy efficient. Gaseous diffusion plants (GDPs) provide about 40% of current world enrichment capacity but are being phased out as newer gas centrifuge enrichment plants (GCEPs) are constructed. Estimates of current and future enrichment capacity are always approximate, due to the constant upgrades, expansions, and shutdowns occurring at enrichment plants, largely determined by economic interests. Currently, the world enrichment capacity is approximately 56 million kilogram separative work units (SWU) per year, with 22.5 million in gaseous diffusion and more than 33 million in gas centrifuge plants. Another 34 million SWU/year of capacity is under construction or planned for the near future, almost entirely using gas centrifuge separation. Other less-efficient techniques have also been used in the past, including electromagnetic and aerodynamic separations, but these are considered obsolete, at least from a commercial perspective. Laser isotope separation shows promise as a possible enrichment technique of the future but has yet to be

  19. Evaluating biomarkers for prognostic enrichment of clinical trials.

    Science.gov (United States)

    Kerr, Kathleen F; Roth, Jeremy; Zhu, Kehao; Thiessen-Philbrook, Heather; Meisner, Allison; Wilson, Francis Perry; Coca, Steven; Parikh, Chirag R

    2017-12-01

    A potential use of biomarkers is to assist in prognostic enrichment of clinical trials, where only patients at relatively higher risk for an outcome of interest are eligible for the trial. We investigated methods for evaluating biomarkers for prognostic enrichment. We identified five key considerations when considering a biomarker and a screening threshold for prognostic enrichment: (1) clinical trial sample size, (2) calendar time to enroll the trial, (3) total patient screening costs and the total per-patient trial costs, (4) generalizability of trial results, and (5) ethical evaluation of trial eligibility criteria. Items (1)-(3) are amenable to quantitative analysis. We developed the Biomarker Prognostic Enrichment Tool for evaluating biomarkers for prognostic enrichment at varying levels of screening stringency. We demonstrate that both modestly prognostic and strongly prognostic biomarkers can improve trial metrics using Biomarker Prognostic Enrichment Tool. Biomarker Prognostic Enrichment Tool is available as a webtool at http://prognosticenrichment.com and as a package for the R statistical computing platform. In some clinical settings, even biomarkers with modest prognostic performance can be useful for prognostic enrichment. In addition to the quantitative analysis provided by Biomarker Prognostic Enrichment Tool, investigators must consider the generalizability of trial results and evaluate the ethics of trial eligibility criteria.

  20. Effects of Stress and Social Enrichment on Alcohol Intake, Biological and Psychological Stress Responses in Rats

    Science.gov (United States)

    2010-06-28

    used were not sophisticated enough to elucidate the pattern. Using a more advanced statistical approach (e.g., Canonical discriminitive analysis...corticotrophin-releasing factor in stress-induced relapse to alcohol- seeking behavior in rats. Psychopharmacology (Berl) 150:317-324. Lex BW (1991) Some gender ...Prunell M, Dimitsantos V, Nadal R, Escorihuela RM (2006) Environmental enrichment effects in social investigation in rats are gender dependent

  1. Foam patterns

    Science.gov (United States)

    Chaudhry, Anil R; Dzugan, Robert; Harrington, Richard M; Neece, Faurice D; Singh, Nipendra P; Westendorf, Travis

    2013-11-26

    A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

  2. Enrichment of Acinetobacter spp. from food samples.

    Science.gov (United States)

    Carvalheira, Ana; Ferreira, Vânia; Silva, Joana; Teixeira, Paula

    2016-05-01

    Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p enrichment. Next, the Dijkshoorn's enrichment followed by direct plating on CHROMagar™ Acinetobacter was applied to detect Acinetobacter spp. in different foods. Fourteen different presumptive acinetobacters were recovered and assumed to represent nine different strains on the basis of REP-PCR typing. Eight of these strains were identified by rpoB gene analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Enrichment of sub-milligram size carbon samples

    NARCIS (Netherlands)

    Kitagawa, H; vanderPlicht, J

    We have developed a carbon isotope enrichment system for use in conjunction with the Groningen Accelerator Mass Spectrometer. Using thermal diffusion of CO, we obtained an enrichment factor of about 3 for C-13 for half-gram carbon in 5 days. This means we expect for C-14 an enrichment factor of 6,

  4. Tritium analysis in natural waters: experimental characteristics of the electrolitic enrichment system of the Chemical Department - Sao Carlos Federal University

    International Nuclear Information System (INIS)

    Mozeto, A.A.; Fontanetti, A.R.

    1986-01-01

    The working conditions of a system for low-level tritium analyses in natural waters were determined using eletrolytic enrichment and liquid scintillation counting techniques. The system installed at the Departamento de Quimica - UFScar is characterized by the following experimental parameters: (a) sample volume reduction factor during eletrolysis = 16.7; (b) tritium recovery factor = 80%; (c) tritium enrichment factor = 13.4; (d) counting efficiency = 12.5%; (e) background level = 11.5 cpm; (f) counting time per sample = 500 minutes; (g) sensitivity = 8.3 TU/cpm; (h) lower detection limit = 3.6 TU + - 50% and (i) analytical capacity = 30 samples/month. It is also discussed the suitability of the analytical system in terms of rain and ground water samples as well. (Author) [pt

  5. Problems of accounting, cost concerns and economic analysis in the mining enrichment industry

    Energy Technology Data Exchange (ETDEWEB)

    Slabinskiy, V T

    1980-01-01

    Mining enrichment enterprises of the ferrous and nonferrous metallurgy, coal and chemical industry have much in common in the area of technology of production, technical base, organization of labor and production. This in turn presupposes the possible development of a common procedure of accounting of expenditures for production, calculation of net cost of output and analysis of production-economic activity of enterprises. Based on scientific research and generalization of advanced experience of practical workers, means of improvement of economic operation in mining enrichment enterprises are outlined according to increasing demands of production control. An outline of analytic accounting of expenditures which provides for multitarget use of information has been developed: for organization of operational control of the formulation of net cost of output, determination of the results of self support activities of structural subdivisions of an enterprise, computation of the efficiency of scientific and technical progress. Experience of use of economic and mathematical methods in computers for this purpose is discussed.

  6. CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY

    International Nuclear Information System (INIS)

    Simon, Joshua D.; Thompson, Ian B.; Shectman, Stephen A.; Jacobson, Heather R.; Frebel, Anna; Adams, Joshua J.

    2015-01-01

    We present a homogeneous chemical abundance analysis of five of the most metal-poor stars in the Sculptor dwarf spheroidal galaxy. We analyze new and archival high resolution spectroscopy from Magellan/MIKE and VLT/UVES and determine stellar parameters and abundances in a consistent way for each star. Two of the stars in our sample, at [Fe/H] = −3.5 and [Fe/H] = −3.8, are new discoveries from our Ca K survey of Sculptor, while the other three were known in the literature. We confirm that Scl 07-50 is the lowest metallicity star identified in an external galaxy, at [Fe/H] = −4.1. The two most metal-poor stars both have very unusual abundance patterns, with striking deficiencies of the α elements, while the other three stars resemble typical extremely metal-poor Milky Way halo stars. We show that the star-to-star scatter for several elements in Sculptor is larger than that for halo stars in the same metallicity range. This scatter and the uncommon abundance patterns of the lowest metallicity stars indicate that the oldest surviving Sculptor stars were enriched by a small number of earlier supernovae, perhaps weighted toward high-mass progenitors from the first generation of stars the galaxy formed

  7. Review of environmental enrichment for broiler chickens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch; Van de Weerd, H.A.; de Jong, I.C.

    2018-01-01

    to improvements of the biological function. This definition has been broadened to include practical and economic aspects, as any enrichment strategy that adversely affects the health of animals or that has too many economic or practical constraints will never be implemented on commercial farms and thus never...... benefit animals. Environmental enrichment for broilers often has the purpose of satisfying behavioral needs and/or stimulating the broilers to an increased level of activity, which among others will reduce the occurrence of leg problems. Potentially successful environmental enrichments for broiler...... chickens are elevated resting-places, panels, barriers, and bales of straw (“point-source enrichment”), as well as covered verandas and outdoor ranges (“complex enriched environments”). Many of the ideas for environmental enrichment for broilers need to be further developed and studied, preferably...

  8. Current perspective of the uranium enrichment market

    International Nuclear Information System (INIS)

    Laughon, K.O.

    1986-01-01

    Over the past several years, developments in the uranium enrichment market have required the Department of Energy (DOE) to make a number of changes in the U.S. enrichment enterprise. These changes have been made to allow DOE to conduct our enrichment business so as to be more responsive to changing market forces. Needless to say, some of these changes have been difficult, but they have been necessary if they are to conduct a healthy and competitive uranium enrichment business in the United States. This paper discusses several topics, including: The Uranium Enrichment Market, Utility Services (US) Contracts, Reduced Prices, Incentive Pricing, Better Customer Services, and Advanced Technology. In addition to these topics, information is provided on the recent court action regarding the US Contracts and the viability finding on the uranium mining industry

  9. CHEMICAL DIVERSITY IN THE ULTRA-FAINT DWARF GALAXY TUCANA II

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Alexander P.; Frebel, Anna; Ezzeddine, Rana [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Casey, Andrew R., E-mail: alexji@mit.edu [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)

    2016-11-20

    We present the first detailed chemical abundance study of the ultra-faint dwarf galaxy Tucana II, based on high-resolution Magellan/MIKE spectra of four red giant stars. The metallicities of these stars range from [Fe/H] = −3.2 to −2.6, and all stars are low in neutron-capture abundances ([Sr/Fe] and [Ba/Fe] < −1). However, a number of anomalous chemical signatures are present. One star is relatively metal-rich ([Fe/H] = −2.6) and shows [Na, α , Sc/Fe] < 0, suggesting an extended star formation history with contributions from AGB stars and SNe Ia. Two stars with [Fe/H] < −3 are mildly carbon-enhanced ([C/Fe] ∼ 0.7) and may be consistent with enrichment by faint supernovae, if such supernovae can produce neutron-capture elements. A fourth star with [Fe/H] = −3 is carbon-normal, and exhibits distinct light element abundance ratios from the carbon-enhanced stars. This carbon-normal star implies that at least two distinct nucleosynthesis sources, both possibly associated with Population III stars, contributed to the early chemical enrichment of this galaxy. Despite its very low luminosity, Tucana II shows a diversity of chemical signatures that preclude it from being a simple “one-shot” first galaxy yet still provide a window into star and galaxy formation in the early universe.

  10. CHEMICAL DIVERSITY IN THE ULTRA-FAINT DWARF GALAXY TUCANA II

    International Nuclear Information System (INIS)

    Ji, Alexander P.; Frebel, Anna; Ezzeddine, Rana; Casey, Andrew R.

    2016-01-01

    We present the first detailed chemical abundance study of the ultra-faint dwarf galaxy Tucana II, based on high-resolution Magellan/MIKE spectra of four red giant stars. The metallicities of these stars range from [Fe/H] = −3.2 to −2.6, and all stars are low in neutron-capture abundances ([Sr/Fe] and [Ba/Fe] < −1). However, a number of anomalous chemical signatures are present. One star is relatively metal-rich ([Fe/H] = −2.6) and shows [Na, α , Sc/Fe] < 0, suggesting an extended star formation history with contributions from AGB stars and SNe Ia. Two stars with [Fe/H] < −3 are mildly carbon-enhanced ([C/Fe] ∼ 0.7) and may be consistent with enrichment by faint supernovae, if such supernovae can produce neutron-capture elements. A fourth star with [Fe/H] = −3 is carbon-normal, and exhibits distinct light element abundance ratios from the carbon-enhanced stars. This carbon-normal star implies that at least two distinct nucleosynthesis sources, both possibly associated with Population III stars, contributed to the early chemical enrichment of this galaxy. Despite its very low luminosity, Tucana II shows a diversity of chemical signatures that preclude it from being a simple “one-shot” first galaxy yet still provide a window into star and galaxy formation in the early universe.

  11. Review of environmental enrichment for broiler chickens.

    Science.gov (United States)

    Riber, A B; van de Weerd, H A; de Jong, I C; Steenfeldt, S

    2018-02-01

    Welfare problems are commonly found in both conventional and organic production of broiler chickens. In order to reduce the extent of welfare problems, it has been suggested to provide stimulating, enriched environments. The aim of the present paper is to provide a review of the effect on behavior and welfare of the different kinds of environmental enrichments in the production of broilers that have been described in the scientific literature. Environmental enrichment is defined as an improvement of the environment of captive animals, which increases the behavioral opportunities of the animal and leads to improvements of the biological function. This definition has been broadened to include practical and economic aspects, as any enrichment strategy that adversely affects the health of animals or that has too many economic or practical constraints will never be implemented on commercial farms and thus never benefit animals. Environmental enrichment for broilers often has the purpose of satisfying behavioral needs and/or stimulating the broilers to an increased level of activity, which among others will reduce the occurrence of leg problems. Potentially successful environmental enrichments for broiler chickens are elevated resting-places, panels, barriers, and bales of straw ("point-source enrichment"), as well as covered verandas and outdoor ranges ("complex enriched environments"). Many of the ideas for environmental enrichment for broilers need to be further developed and studied, preferably in commercial trials, with respect to the use, the effect on behavior and on other welfare aspects such as leg health, and the interaction with genotype, production system, stocking density, light, and flock size. In addition, information on the practical application and the economics of the production system is often lacking, although it is important for application in practice. © 2017 Poultry Science Association Inc.

  12. Super enrichment of Fe-group nuclei in solar flares and their association with large 3He enrichments

    International Nuclear Information System (INIS)

    Anglin, J.D.; Dietrich, W.F.; Simpson, J.A.

    1977-01-01

    ''Fe''/He ratios at approximately 2 MeV/n have been measured in 60 solar flares and periods of enhanced fluxes during the interval 1972-1976. The observed ditribution of ratios is extremely wide with values ranging from approximately 1 to more than 1000 times the solar abundance ratio. In constrast, most of the CHO/He ratios for the same flares lie within a factor 2 of the observed mean value of 2 x 10 -2 . While experimental limitations prevent a complete correlation study of Fe-group and 3 He abundances, comparison of flares with large Fe enrichments with flares with large 3 He enrichments for the period 1969-1976 shows that a 3 He-rich flare is also likely to be rich in iron. We feel that the association of 3 He and Fe enrichments may be explained by a two-stage process in which a preliminary enrichment of heavy nuclei precedes the preferential acceleration of ambient 3 He. Nuclear interactions are ruled out as the principal source of the enriched 3 He. (author)

  13. A Detailed Study of Chemical Enrichment History of Galaxy Clusters out to Virial Radius

    Science.gov (United States)

    Loewenstein, Michael

    The origin of the metal enrichment of the intracluster medium (ICM) represents a fundamental problem in extragalactic astrophysics, with implications for our understanding of how stars and galaxies form, the nature of Type Ia supernova (SNIa) progenitors, and the thermal history of the ICM. These heavy elements are ultimately synthesized by supernova (SN) explosions; however, the details of the sites of metal production and mechanisms that transport metals to the ICM remain unclear. To make progress, accurate abundance profiles for multiple elements extending from the cluster core out to the virial radius (r180) are required for a significant cluster sample. We propose an X-ray spectroscopic study of a carefully-chosen sample of archival Suzaku and XMM-Newton observations of 23 clusters: XMM-Newton data probe the cluster temperature and abundances out to (0.5-1)r500, while Suzaku data probe the cluster outskirts. A method devised by our team to utilize all elements with emission lines in the X-ray bandpass to measure the relative contributions of supernova explosions by direct modeling of their X-ray spectra will be applied in order to constrain the demographics of the enriching supernova population. In addition we will conduct a stacking analysis of our already existing Suzaku and XMM-Newton cluster spectra to search for weak emssion lines that are important SN diagnostics, and to look for trends with cluster mass and redshift. The funding we propose here will also support the data analysis of our recent Suzaku observations of the archetypal cluster A3112 (200 ks each on the core and outskirts). Our data analysis, intepreted using theoretical models we have developed, will enable us to constrain the star formation history, SN demographics, and nature of SNIa progenitors associated with galaxy cluster stellar populations - and, hence, directly addresess NASA s Strategic Objective 2.4.2 in Astrophysics that aims to improve the understanding of how the Universe works

  14. Study on the radiotoxicology of enriched uranium

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Zheng Siying; Wang Guolin; Wang Chongdao; Cao Genfa

    1987-12-01

    A study on the retentive peculiarity of soluble enriched uranium UO 2 F 2 were observed after iv once or consecutive ip qd x 3d to Wistar male rats. The dynamic retention of radioactivity in the body showed that the enriched uranium UO 2 F 2 was chiefly localized in kidney, and then in skeleton and liver. The radioactivity of the enriched uranium UO 2 F 2 in skeleton rose steadily while the concentratoin in kidney and liver droped. When enriched uranium UO 2 F 2 was accumulated in organism, it caused chromosome aberrations on bone marrow cells. Results indicated that the chromosome aberration rates were elevated when the dose of the enriched uranium UO 2 F 2 was increased, at the same time, the cell division was depressed. Accumulation of insoluble enriched uranium U 3 O 8 in gastrointestinal tract was well described by a two exponential expression. Values of retention estimate for fast component, T 1 = 0.34 d, and for relatively long term component, T 2 = 4.05 d. The deposition of UO 2 F 2 in the intact skin was only 0.16 to 0.18% of the total contaminated UO 2 F 2 . Penetration of the enriched uranium UO 2 F 2 was dominantly increased in abraded skin. This value is about 25 to 32 times as compaired with that in intact skin. Retention of the enriched uranium UO 2 F 2 through abraded skins was dominantly localized in kidney and skeleton

  15. Enrichment technology. Dependable vendor of gas centrifuges

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    Enrichment Technology is an innovative, high-tech company that develops, manufactures and installs gas centrifuges for enriching uranium. In addition, Enrichment Technology designs enrichment plants that use gas centrifuge technology. This technology offers the most efficient and cost-effective method for enriching uranium yet: high-performance, safe technology that dominates the market with a global share of 45 percent. A determining factor in Enrichment Technology's success is its mission: supplying its customers with safe, reliable technology. Production of the centrifuges requires versatile know-how and collaboration between different departments as well as interdisciplinary teams at the various sites. More than 2000 operators at 8 sites in 5 countries contribute their individual knowledge and personal skills in order to produce this exceptional technology. The head office is in Beaconsfield near London and the operational headquarters are in Almelo in the Netherlands. There are other sites in Germany (Juelich und Gronau), Great Britain (Capenhurst) as well as project sites in the USA and France. Capenhurst is where experienced engineers design new enrichment plants and organise their construction. Centrifuge components are manufactured in Almelo and Juelich, while the pipework needed to connect up the centrifuges is produced at the site in Gronau. In Juelich, highly qualified scientists in interdisciplinary teams are continuously researching ways of improving the current centrifuges. Communication between specialists in the fields of chemistry, physics and engineering forms the basis for the company's success and the key to extending this leading position in the global enrichment market. (orig.)

  16. Comments on applications of reduced enrichment fuels

    International Nuclear Information System (INIS)

    Winkler, M.H.

    1983-01-01

    Full text: I will briefly describe the experience gained using different fuels in the SAPHIR reactor in Switzerland. The SAPHIR has been operating since 1957 and was the first swimming pool reactor built outside of the United States, which was originally known as the Geneva Conference Reactor. The first core was loaded with 20 percent enriched high density UO 2 fuel with a density of about 2.5 grams per cc, fabricated in 1955 by Oak Ridge National Laboratory. After a few years of operation at a power level of one MW, more than one batch of the elements released small amounts of fission products mainly Xe and Kr. When these releases were discovered, high enriched fuel was becoming available so that the fuel fabricators began to produce the lower density high enriched fuels. During this transition from fabrication of low to high enriched fuels no one could foresee that the stone age of nuclear fuel fabrication would come back again. Therefore, we did not investigate the reasons for the fission product release from the high density low enriched UO 2 fuel. The second fuel type used in the SAPHIR was the 90 percent enriched low density U 3 O 8 fuel fabricated by NUKEM. This high enriched fuel has performed satisfactorily over the years. Since 1968, the core has been using improved 23 plate fuel elements with a loading of 280 grams of uranium. The reactor power has been recently increased to five MW. An additional increase in the power level to 10 MW is planned at the end of next year so that heavier loaded elements will be needed. In order to follow the recommendations of the INFCE working group 8C and in cooperation with the reduced enrichment program, we intend to initially reduce the fuel enrichment to 45 percent. Last year we ordered five fuel elements with a loading of 320 grams 235 U/element and 45 percent enrichment for full power tests. Unfortunately, the delivery of the necessary enriched fuel uranium has been delayed and it is not available at this time. If

  17. Descendants of the first stars: the distinct chemical signature of second generation stars

    Science.gov (United States)

    Hartwig, Tilman; Yoshida, Naoki; Magg, Mattis; Frebel, Anna; Glover, Simon C. O.; Gómez, Facundo A.; Griffen, Brendan; Ishigaki, Miho N.; Ji, Alexander P.; Klessen, Ralf S.; O'Shea, Brian W.; Tominaga, Nozomu

    2018-05-01

    Extremely metal-poor (EMP) stars in the Milky Way (MW) allow us to infer the properties of their progenitors by comparing their chemical composition to the metal yields of the first supernovae. This method is most powerful when applied to mono-enriched stars, i.e. stars that formed from gas that was enriched by only one previous supernova. We present a novel diagnostic to identify this subclass of EMP stars. We model the first generations of star formation semi-analytically, based on dark matter halo merger trees that yield MW-like halos at the present day. Radiative and chemical feedback are included self-consistently and we trace all elements up to zinc. Mono-enriched stars account for only ˜1% of second generation stars in our fiducial model and we provide an analytical formula for this probability. We also present a novel analytical diagnostic to identify mono-enriched stars, based on the metal yields of the first supernovae. This new diagnostic allows us to derive our main results independently from the specific assumptions made regarding Pop III star formation, and we apply it to a set of observed EMP stars to demonstrate its strengths and limitations. Our results may provide selection criteria for current and future surveys and therefore contribute to a deeper understanding of EMP stars and their progenitors.

  18. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal

    2015-12-22

    The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  19. Continuous monitoring of variations in the 235U enrichment of uranium in the header pipework of a centrifuge enrichment plant

    International Nuclear Information System (INIS)

    Packer, T.W.

    1991-01-01

    Non-destructive assay equipment, based on gamma-ray spectrometry and x-ray fluorescence analysis has previously been developed for confirming the presence of low enriched uranium in the header pipework of UF 6 gas centrifuge enrichment plants. However inspections can only be carried out occasionally on a limited number of pipes. With the development of centrifuge enrichment technology it has been suggested that more frequent, or ideally, continuous measurements should be made in order to improve safeguards assurance between inspections. For this purpose we have developed non-destructive assay equipment based on continuous gamma-ray spectrometry and x-ray transmission measurements. This equipment is suitable for detecting significant changes in the 235 U enrichment of uranium in the header pipework of new centrifuge enrichment plants. Results are given in this paper of continuous measurements made in the laboratory and also on header pipework of a centrifuge enrichment plant at Capenhurst

  20. Enriching an effect calculus with linear types

    DEFF Research Database (Denmark)

    Egger, Jeff; Møgelberg, Rasmus Ejlers; Simpson, Alex

    2009-01-01

    We define an ``enriched effect calculus'' by conservatively extending  a type theory for computational effects with primitives from linear logic. By doing so, we obtain a generalisation of linear type theory, intended as a formalism for expressing linear aspects of effects. As a worked example, we...... formulate  linearly-used continuations in the enriched effect calculus. These are captured by a fundamental translation of the enriched effect calculus into itself, which extends existing call-by-value and call-by-name linearly-used CPS translations. We show that our translation is involutive. Full...... completeness results for the various linearly-used CPS translations  follow. Our main results, the conservativity of enriching the effect calculus with linear primitives, and the involution property of the fundamental translation, are proved using a category-theoretic semantics for the enriched effect calculus...

  1. Highly specific purification of N-glycans using phosphate-based derivatization as an affinity tag in combination with Ti{sup 4+}-SPE enrichment for mass spectrometric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying [Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Key Laboratory of Glycoconjugates Research Ministry of Public Health, Fudan University, Shanghai 200032 (China); Peng, Ye; Bin, Zhichao [Department of Chemistry, Fudan University, Shanghai 200032 (China); Wang, Huijie [Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Lu, Haojie, E-mail: luhaojie@fudan.edu.cn [Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Department of Chemistry, Fudan University, Shanghai 200032 (China); Key Laboratory of Glycoconjugates Research Ministry of Public Health, Fudan University, Shanghai 200032 (China)

    2016-08-31

    N-linked protein glycosylation is involved in regulation of a wide variety of cellular processes and associated with numerous diseases. Highly specific identification of N-glycome remains a challenge while its biological significance is acknowledged. The relatively low abundance of glycan in complex biological mixtures, lack of basic sites for protonation, and suppression by other highly abundant proteins/peptides lead to the particularly poor detection sensitivity of N-glycans in the MS analysis. Therefore, the highly specific purification procedure becomes a crucial step prior to MS analysis of the N-glycome. Herein, a novel N-glycans enrichment approach based on phosphate derivatization combined with Ti{sup 4+}-SPE (solid phase extraction) was developed. Briefly, in this strategy, N-glycans were chemically labeled with a phospho-group at their reducing ends, such that the Ti{sup 4+}-SPE microspheres were able to capture the phospho-containing glycans. The enrichment method was developed and optimized using model oligosaccharides (maltoheptaose DP7 and sialylated glycan A1) and also glycans from a standard glycoprotein (asialofetuin, ASF). This method experimentally showed high derivatization efficiency (almost 100%), excellent selectivity (analyzing DP7 in the digests of bovine serum albumin at a mass ratio of 1:100), high enriching recovery (90%), good reproducibility (CV<15%) as well as high sensitivity (LOD at fmol level). At last, the proposed method was successfully applied in the profiling of N-glycome in human serum, in which a total of 31 N-glycan masses were identified. - Graphical abstract: A selective enrichment method for the N-glycome is reported. N-glycans were chemically labeled with a phosphate derivatization reagent (AMS), then the phospho-containing glycans were enriched using Ti{sup 4+}-microspheres. - Highlights: • A highly specific N-glycans purification method based on phosphate derivatization combined with Ti{sup 4+}-SPE was developed

  2. Hypothalamic digoxin, hemispheric chemical dominance, and the tridosha theory.

    Science.gov (United States)

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-05-01

    Ayurveda, the traditional Indian System of Medicine, deals with the theory of the three tridosha states (both physical and psychological): Vata, Pitta, and Kapha. They are the three major human constitutional types that both depend on psychological and physical characteristics. The Pitta state is described as a critical, discriminative, and rational psychological state of mind, while the Kapha state is described as being dominant for emotional stimuli. The Vata state is an intermediate unstable shifting state. The Pitta types are of average height and built with well developed musculature. The Vata types are thin individuals with low body mass index. The Kapha types are short stocky individuals that tend toward obesity, and who are sedentary. The study assessed the biochemical differences between right hemispheric dominant, bihemispheric dominant, and left hemispheric dominant individuals, and then compared this with the patterns obtained in the Vata, Pitta, and Kapha states. The isoprenoid metabolites (digoxin, dolichol, and ubiquinone), glycoconjugate metabolism, free radical metabolism, and the RBC membrane composition were studied. The hemispheric chemical dominance in various systemic diseases and psychological states was also investigated. The results showed that right hemispheric chemically dominant/Kapha state had elevated digoxin levels, increased free radical production and reduced scavenging, increased tryptophan catabolites and reduced tyrosine catabolites, increased glycoconjugate levels and increased cholesterol: phospholipid ratio of RBC membranes. Left hemispheric chemically dominant/Pitta states had the opposite biochemical patterns. The patterns were normal or intermediate in the bihemispheric chemically dominant/Vata state. This pattern could be correlated with various systemic and neuropsychiatric diseases and personality traits. Right hemispheric chemical dominance/Kapha state represents a hyperdigoxinemic state with membrane sodium

  3. Multinational uranium enrichment in the Middle East

    International Nuclear Information System (INIS)

    Ahmad, Ali; Salahieh, Sidra; Snyder, Ryan

    2017-01-01

    The Joint Comprehensive Plan of Action (JCPOA) agreed to by Iran and the P5+1 in July 2015 placed restrictions on Iran’s nuclear program while other Middle Eastern countries– Egypt, Jordan, Saudi Arabia, Turkey, and the United Arab Emirates–are planning to build their own nuclear power plants to meet increasing electricity demands. Although the JCPOA restricts Iran's uranium enrichment program for 10–15 years, Iran's neighbors may choose to develop their own national enrichment programs giving them a potential nuclear weapons capability. This paper argues that converting Iran's national enrichment program to a more proliferation-resistant multinational arrangement could offer significant economic benefits–reduced capital and operational costs–due to economies of scale and the utilization of more efficient enrichment technologies. In addition, the paper examines policy aspects related to financing, governance, and how multinational enrichment could fit into the political and security context of the Middle East. A multinational enrichment facility managed by regional and international partners would provide more assurance that it remains peaceful and could help build confidence between Iran and its neighbors to cooperate in managing other regional security challenges. - Highlights: • Freezing Iran's nuclear program is an opportunity to launch joint initiatives in ME. • A joint uranium enrichment program in the Middle East offers economic benefits. • Other benefits include improved nuclear security and transparency in the region.

  4. PURIFICATION AND ENRICHMENT OF BIOGAS IN ASH-WATER MIXTURE

    Directory of Open Access Journals (Sweden)

    Andrzej Brudniak

    2014-10-01

    Full Text Available Biogas, produced in an aerobic digestion process, is a mixture of gases, and that is why its inexpensive and effective valorisation is essential. Research on this process is necessary in order to use biogas as a renewable energy source. The aim of this thesis is to present methods of biogas purification and enrichment in the fly ash - water mixture, that is generated on the base of fly ash produced during burning coal in power industry. Experience presented that the fly ash absorbs CO2 and H2S, even in conventional conditions. The absorption efficiency depends not only on the chemical composition of the ash but also on its physical properties. There was also a strong neutralization of alkaline waste combustion.

  5. Bio-active nanoemulsions enriched with gold nanoparticle, marigold extracts and lipoic acid: In vitro investigations.

    Science.gov (United States)

    Guler, Emine; Barlas, F Baris; Yavuz, Murat; Demir, Bilal; Gumus, Z Pinar; Baspinar, Yucel; Coskunol, Hakan; Timur, Suna

    2014-09-01

    A novel and efficient approach for the preparation of enriched herbal formulations was described and their potential applications including wound healing and antioxidant activity (cell based and cell free) were investigated via in vitro cell culture studies. Nigella sativa oil was enriched with Calendula officinalis extract and lipoic acid capped gold nanoparticles (AuNP-LA) using nanoemulsion systems. The combination of these bio-active compounds was used to design oil in water (O/W) and water in oil (W/O) emulsions. The resulted emulsions were characterized by particle size measurements. The phenolic content of each nanoemulsion was examined by using both colorimetric assay and chromatographic analyses. Two different methods containing cell free chemical assay (1-diphenyl-2-picrylhydrazyl method) and cell based antioxidant activity test were used to evaluate the antioxidant capacities. In order to investigate the bio-activities of the herbal formulations, in vitro cell culture experiments, including cytotoxicity, scratch assay, antioxidant activity and cell proliferation were carried out using Vero cell line as a model cell line. Furthermore, to monitor localization of the nanoemulsions after application of the cell culture, the cell images were monitored via fluorescence microscope after FITC labeling. All data confirmed that the enriched N. sativa formulations exhibited better antioxidant and wound healing activity than N. sativa emulsion without any enrichment. In conclusion, the incorporation of AuNP-LA and C. officinalis extract into the N. sativa emulsions significantly increased the bio-activities. The present work may support further studies about using the other bio-active agents for the enrichment of herbal preparations to strengthen their activities. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. 21 CFR 137.260 - Enriched corn meals.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched corn meals. 137.260 Section 137.260 Food... Flours and Related Products § 137.260 Enriched corn meals. (a) Enriched corn meals are the foods, each of which conforms to the definition and standard of identity prescribed for a kind of corn meal by §§ 137...

  7. PC based uranium enrichment analyser

    International Nuclear Information System (INIS)

    Madan, V.K.; Gopalakrishana, K.R.; Bairi, B.R.

    1991-01-01

    It is important to measure enrichment of unirradiated nuclear fuel elements during production as a quality control measure. An IBM PC based system has recently been tested for enrichment measurements for Nuclear Fuel Complex (NFC), Hyderabad. As required by NFC, the system has ease of calibration. It is easy to switch the system from measuring enrichment of fuel elements to pellets and also automatically store the data and the results. The system uses an IBM PC plug in card to acquire data. The card incorporates programmable interval timers (8253-5). The counter/timer devices are executed by I/O mapped I/O's. A novel algorithm has been incorporated to make the system more reliable. The application software has been written in BASIC. (author). 9 refs., 1 fig

  8. A Summary of Actinide Enrichment Technologies and Capability Gaps

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Bradley D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robinson, Sharon M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    The evaluation performed in this study indicates that a new program is needed to efficiently provide a national actinide radioisotope enrichment capability to produce milligram-to-gram quantities of unique materials for user communities. This program should leverage past actinide enrichment, the recent advances in stable isotope enrichment, and assessments of the future requirements to cost effectively develop this capability while establishing an experience base for a new generation of researchers in this vital area. Preliminary evaluations indicate that an electromagnetic isotope separation (EMIS) device would have the capability to meet the future needs of the user community for enriched actinides. The EMIS technology could be potentially coupled with other enrichment technologies, such as irradiation, as pre-enrichment and/or post-enrichment systems to increase the throughput, reduce losses of material, and/or reduce operational costs of the base EMIS system. Past actinide enrichment experience and advances in the EMIS technology applied in stable isotope separations should be leveraged with this new evaluation information to assist in the establishment of a domestic actinide radioisotope enrichment capability.

  9. Multicomponent patterned ultrathin carbon nanomembranes by laser ablation

    Science.gov (United States)

    Frese, Natalie; Scherr, Julian; Beyer, André; Terfort, Andreas; Gölzhäuser, Armin; Hampp, Norbert; Rhinow, Daniel

    2018-01-01

    Carbon nanomembranes (CNMs) are a class of two-dimensional materials, which are obtained by electron beam-induced crosslinking of aromatic self-assembled monolayers (SAMs) on solid substrates. CNMs made from a single type of precursor molecule are uniform with homogeneous chemical and physical properties. We have developed a method for the fabrication of internally patterned CNMs resembling a key feature of biological membranes. Direct laser patterning is used to obtain multicomponent patterned SAMs on gold, which are subsequently crosslinked by electron irradiation. We demonstrate that the structure of internally patterned CNMs is preserved upon transfer to different substrates. The method enables rapid fabrication of patterned 2D materials with local variations in chemical and physical properties on the micrometer to centimeter scale.

  10. Uranium enrichment (a strategy analysis overview)

    International Nuclear Information System (INIS)

    Blahnik, C.

    1979-08-01

    An analysis of available information on enrichment technology, separative work supply and demand, and SWU cost is presented. Estimates of present and future enrichment costs are provided for use in strategy analyses of alternate nuclear fuel cycles and systems. (auth)

  11. Providing incentives to buy US enrichment

    International Nuclear Information System (INIS)

    Steyn, J.

    1985-01-01

    The U.S. Department of Energy is making a series of commercial and technological decisions crucial to its future as an enriching enterprise. The state of US enrichment, as revealed in this years AIF Fuel Cycle conference, is reported. (U.K.)

  12. Isotope pattern deconvolution as a tool to study iron metabolism in plants.

    Science.gov (United States)

    Rodríguez-Castrillón, José Angel; Moldovan, Mariella; García Alonso, J Ignacio; Lucena, Juan José; García-Tomé, Maria Luisa; Hernández-Apaolaza, Lourdes

    2008-01-01

    Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using 57Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned 57Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low 57Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of 57Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample.

  13. Isotope pattern deconvolution as a tool to study iron metabolism in plants

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Castrillon, Jose A.; Moldovan, Mariella; Garcia Alonso, J.I. [University of Oviedo, Department of Physical and Analytical Chemistry, Oviedo (Spain); Lucena, Juan J.; Garcia-Tome, Maria L.; Hernandez-Apaolaza, Lourdes [Autonoma University of Madrid, Department of Agricultural Chemistry, Madrid (Spain)

    2008-01-15

    Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using {sup 57}Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned {sup 57}Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low {sup 57}Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of {sup 57}Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample. (orig.)

  14. Exploring consumer exposure pathways and patterns of use for chemicals in the environment

    Directory of Open Access Journals (Sweden)

    Kathie L. Dionisio

    Full Text Available •To assign use-related information to chemicals to help prioritize which will be given more scrutiny relative to human exposure potential.•Categorical chemical use and functional information are presented through the Chemical/Product Categories Database (CPCat.•CPCat contains information on >43,000 unique chemicals mapped to ∼800 terms categorizing their usage or function.•The CPCat database is useful for modeling and prioritizing human chemical exposures.Humans are exposed to thousands of chemicals in the workplace, home, and via air, water, food, and soil. A major challenge in estimating chemical exposures is to understand which chemicals are present in these media and microenvironments. Here we describe the Chemical/Product Categories Database (CPCat, a new, publically available (http://actor.epa.gov/cpcat database of information on chemicals mapped to “use categories” describing the usage or function of the chemical. CPCat was created by combining multiple and diverse sources of data on consumer- and industrial-process based chemical uses from regulatory agencies, manufacturers, and retailers in various countries. The database uses a controlled vocabulary of 833 terms and a novel nomenclature to capture and streamline descriptors of chemical use for 43,596 chemicals from the various sources. Examples of potential applications of CPCat are provided, including identifying chemicals to which children may be exposed and to support prioritization of chemicals for toxicity screening. CPCat is expected to be a valuable resource for regulators, risk assessors, and exposure scientists to identify potential sources of human exposures and exposure pathways, particularly for use in high-throughput chemical exposure assessment. keywords: ACToR,Aggregated Computational Toxicology Resource,AICS,Australian Inventory of Chemical Substances,CAS RN,Chemical Abstracts Service Registry Number,CDR,Chemical Data Reporting Rule,CPCat,Chemical

  15. TRU waste form studies with special reference to iron-enriched basalt: 1980. Annual report

    International Nuclear Information System (INIS)

    Flinn, J.E.; Henslee, S.P.; Kelsey, P.V. Jr.

    1981-06-01

    Material studies were performed on iron-enriched basalt (IEB) as a waste form containment medium for transuranic wastes. Specimens from laboratory scale, as well as large scale melts, were used in the evaluation. The studies included melting and casting, slag-refractory interaction, slag fruit assessments, volatility of sodium salts from IEB melts, chemical and structure homogeneity, metallic dissolution tests, physical properties, and devitrification associated with the development of mineral phases. In addition, durability tests, which included leaching and mechanical behavior, were performed

  16. Diesel-Enriched Particulate Matter Functionally Activates Human Dendritic Cells

    Science.gov (United States)

    Porter, Michael; Karp, Matthew; Killedar, Smruti; Bauer, Stephen M.; Guo, Jia; Williams, D'Ann; Breysse, Patrick; Georas, Steve N.; Williams, Marc A.

    2007-01-01

    Epidemiologic studies have associated exposure to airborne particulate matter (PM) with exacerbations of asthma. It is unknown how different sources of PM affect innate immunity. We sought to determine how car- and diesel exhaust–derived PM affects dendritic cell (DC) activation. DC development was modeled using CD34+ hematopoietic progenitors. Airborne PM was collected from exhaust plenums of Fort McHenry Tunnel providing car-enriched particles (CEP) and diesel-enriched particles (DEP). DC were stimulated for 48 hours with CEP, DEP, CD40-ligand, or lipopolysaccharide. DC activation was assessed by flow cytometry, enzyme-linked immunosorbent assay, and standard culture techniques. DEP increased uptake of fluorescein isothiocyanate–dextran (a model antigen) by DC. Diesel particles enhanced cell-surface expression of co-stimulatory molecules (e.g., CD40 [P < 0.01] and MHC class II [P < 0.01]). By contrast, CEP poorly affected antigen uptake and expression of cell surface molecules, and did not greatly affect cytokine secretion by DC. However, DEP increased production of TNF, IL-6, and IFN-γ (P < 0.01), IL-12 (P < 0.05), and vascular endothelial growth factor (P < 0.001). In co-stimulation assays of PM-exposed DC and alloreactive CD4+ T cells, both CEP and DEP directed a Th2-like pattern of cytokine production (e.g., enhanced IL-13 and IL-18 and suppressed IFN-γ production). CD4+ T cells were not functionally activated on exposure to either DEP or CEP. Car- and diesel-enriched particles exert a differential effect on DC activation. Our data support the hypothesis that DEP (and to a lesser extent CEP) regulate important functional aspects of human DC, supporting an adjuvant role for this material. PMID:17630318

  17. Nitrogen-enriched hierarchically porous carbons prepared from polybenzoxazine for high-performance supercapacitors.

    Science.gov (United States)

    Wan, Liu; Wang, Jianlong; Xie, Lijing; Sun, Yahui; Li, Kaixi

    2014-09-10

    Nitrogen-enriched hierarchically porous carbons (HPCs) were synthesized from a novel nitrile-functionalized benzoxazine based on benzoxazine chemistry using a soft-templating method and a potassium hydroxide (KOH) chemical activation method and used as electrode materials for supercapacitors. The textural and chemical properties could be easily tuned by adding a soft template and changing the activation temperature. The introduction of the soft-templating agent (surfactant F127) resulted in the formation of mesopores, which facilitated fast ionic diffusion and reduced the internal resistance. The micropores of HPCs were extensively developed by KOH activation to provide large electrochemical double-layer capacitance. As the activation temperature increased from 600 to 800 °C, the specific surface area of nitrogen-enriched carbons increased dramatically, micropores were enlarged, and more meso/macropores were developed, but the nitrogen and oxygen content decreased, which affected the electrochemical performance. The sample HPC-800 activated at 800 °C possesses a high specific surface area (1555.4 m(2) g(-1)), high oxygen (10.61 wt %) and nitrogen (3.64 wt %) contents, a hierarchical pore structure, a high graphitization degree, and good electrical conductivity. It shows great pseudocapacitance and the largest specific capacitance of 641.6 F g(-1) at a current density of 1 A g(-1) in a 6 mol L(-1) KOH aqueous electrolyte when measured in a three-electrode system. Furthermore, the HPC-800 electrode exhibits excellent rate capability (443.0 F g(-1) remained at 40 A g(-1)) and good cycling stability (94.3% capacitance retention over 5000 cycles).

  18. Chemical fingerprint of iron oxides related to iron enrichment of banded iron formation from the Cauê Formation - Esperança Deposit, Quadrilátero Ferrífero, Brazil: a laser ablation ICP-MS study

    Directory of Open Access Journals (Sweden)

    Lucilia Aparecida Ramos de Oliveira

    Full Text Available Chemical signatures of iron oxides from dolomitic itabirite and high-grade iron ore from the Esperança deposit, located in the Quadrilátero Ferrífero, indicate that polycyclic processes involving changing of chemical and redox conditions are responsible for the iron enrichment on Cauê Formation from Minas Supergroup. Variations of Mn, Mg and Sr content in different generations of iron oxides from dolomitic itabirite, high-grade iron ore and syn-mineralization quartz-carbonate-hematite veins denote the close relationship between high-grade iron ore formation and carbonate alteration. This indicates that dolomitic itabirite is the main precursor of the iron ore in that deposit. Long-lasting percolation of hydrothermal fluids and shifts in the redox conditions have contributed to changes in the Y/Ho ratio, light/heavy rare earth elements ratio and Ce anomaly with successive iron oxide generations (martite-granular hematite, as well as lower abundance of trace elements including rare earth elements in the younger specularite generations.

  19. Linking environmental nutrient enrichment and disease emergence in humans and wildlife

    Science.gov (United States)

    Johnson, Pieter T. J.; Townsend, Alan R.; Cleveland, Cory C.; Glibert, Patricia M.; Howarth, Robert W.; McKenzie, Valerie J.; Rejmankova, Eliska; Ward, Mary H.

    2009-01-01

    Worldwide increases in the numbers of human and wildlife diseases present ecologists with the challenge of understanding how large-scale environmental changes affect host-parasite interactions. One of the most profound changes to Earth’s ecosystems is the alteration of global nutrient cycles, including those of phosphorus (P) and especially nitrogen (N). Alongside the obvious direct benefits of nutrient application for food production, growing evidence suggests that anthropogenic inputs of N and P can indirectly affect the abundance of infectious and noninfectious pathogens, sometimes leading to epidemic conditions. However, the mechanisms underpinning observed correlations, and how such patterns vary with disease type, have long remained conjectural. Here, we discuss recent experimental advances in this area to critically evaluate the relationship between environmental nutrient enrichment and disease. Given the inter-related nature of human and wildlife disease emergence, we include a broad range of human and wildlife examples from terrestrial, marine and freshwater ecosystems. We examine the consequences of nutrient pollution on directly transmitted, vector-borne, complex life cycle, and noninfectious pathogens, including West Nile virus, malaria, harmful algal blooms, coral reef diseases and amphibian malformations. Our synthetic examination suggests that the effects of environmental nutrient enrichment on disease are complex and multifaceted, varying with the type of pathogen, host species and condition, attributes of the ecosystem and the degree of enrichment; some pathogens increase in abundance whereas others decline or disappear. Nevertheless, available evidence indicates that ecological changes associated with nutrient enrichment often exacerbate infection and disease caused by generalist parasites with direct or simple life cycles. Observed mechanisms include changes in host/vector density, host distribution, infection resistance, pathogen virulence or

  20. Chemical Abundance Analysis of Three α-poor, Metal-poor Stars in the Ultrafaint Dwarf Galaxy Horologium I

    Science.gov (United States)

    Nagasawa, D. Q.; Marshall, J. L.; Li, T. S.; Hansen, T. T.; Simon, J. D.; Bernstein, R. A.; Balbinot, E.; Drlica-Wagner, A.; Pace, A. B.; Strigari, L. E.; Pellegrino, C. M.; DePoy, D. L.; Suntzeff, N. B.; Bechtol, K.; Walker, A. R.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; Davis, C.; Desai, S.; Doel, P.; Eifler, T. F.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Hartley, W. G.; Honscheid, K.; James, D. J.; Jeltema, T.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; March, M.; Miquel, R.; Nord, B.; Roodman, A.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; Wechsler, R. H.; Wolf, R. C.; Yanny, B.

    2018-01-01

    We present chemical abundance measurements of three stars in the ultrafaint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high-resolution spectroscopic observations, we measure the metallicity of the three stars, as well as abundance ratios of several α-elements, iron-peak elements, and neutron-capture elements. The abundance pattern is relatively consistent among all three stars, which have a low average metallicity of [Fe/H] ∼ ‑2.6 and are not α-enhanced ([α/Fe] ∼ 0.0). This result is unexpected when compared to other low-metallicity stars in the Galactic halo and other ultrafaint dwarfs and suggests the possibility of a different mechanism for the enrichment of Hor I compared to other satellites. We discuss possible scenarios that could lead to this observed nucleosynthetic signature, including extended star formation, enrichment by a Population III supernova, and or an association with the Large Magellanic Cloud. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This paper also includes data based on observations made with the ESO Very Large Telescope at Paranal Observatory, Chile (ID 096.D-0967(B); PI: E. Balbinot).

  1. Synthesis of 15N-enriched fertilizers. Pt. II. Synthesis of 15N-enriched urea

    International Nuclear Information System (INIS)

    Bondassolli, J.A.; Trivelin, P.C.O.; Mortatti, J.; Victoria, R.L.

    1988-01-01

    The results of studies on the production of 15 N-urea through the reaction between 15 N-enriched anhidrous ammonia, carbon monoxide and sulfur, using hydrogen sulfite as a auto catalizers and methyl alcohol as a liquid reaction medium is presented. The influence of the quantities of reagents on final yield of synthesised urea were studied. Analysis of the cost of 5 Atoms % 15 N-enriched urea were made. (M.A.C.) [pt

  2. Content of bioactive compounds and antioxidant capacity of pumpkin puree enriched with japanese quince, cornelian cherry, strawberry and apples.

    Science.gov (United States)

    Nawirska-Olszańska, Agnieszka; Biesiada, Anita; Sokół-Łętowska, Anna; Kucharska, Alicja Z

    2011-01-01

    When evaluated in terms of taste, smell or active ingredients, pumpkin in itself is not very attractive as a raw material. Hence, it is recommended to blend pumpkin with other fruits, which are aromatic, have a defined taste, and contain a large quantity of active ingredients and organic acids to improve its palatibility. The pumpkin chosen for the experiments was of the variety Karowita, of species Cucurbita maxima. Ten different of compositions were prepared for the purpose of the study: 10, 20 and 30% (w/w) of Japanese quince and cornelian cherry each, or 20 and 30% (w/w) of strawberry and apple each. The puree was then analysed for dry matter, extract, viscosity, colour, vitamin C, total polyphenols, carotenoids and DPPH. The highest content of vitamin C, which was in direct proportion to the quantity of the supplement added (17.88 to 23.43 mg·100 g(-1)), was detected in the quince-enriched puree. The lowest vitamin C content was determined in apple-enriched samples (1.36 to 1.6 mg·100 g(-1)). A similar pattern was observed with total polyphenols: the highest values were measured in quince-enriched puree, and the lowest in the puree supplemented with apple. Taking into account antioxidant properties of the samples, quince-enriched pumpkin puree was found to be the most attractive, and apple-enriched pumpkin puree the least attractive one. The results suggest a wide range of application for pumpkin puree enriched with various additives.

  3. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    Mohapatra, K.K.; Bose, Arun

    2014-01-01

    10 B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10 B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH) 4 - ) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10 B and 11 B

  4. Exploring consumer exposure pathways and patterns of use for chemicals in the environment.

    Science.gov (United States)

    Dionisio, Kathie L; Frame, Alicia M; Goldsmith, Michael-Rock; Wambaugh, John F; Liddell, Alan; Cathey, Tommy; Smith, Doris; Vail, James; Ernstoff, Alexi S; Fantke, Peter; Jolliet, Olivier; Judson, Richard S

    2015-01-01

    Humans are exposed to thousands of chemicals in the workplace, home, and via air, water, food, and soil. A major challenge in estimating chemical exposures is to understand which chemicals are present in these media and microenvironments. Here we describe the Chemical/Product Categories Database (CPCat), a new, publically available (http://actor.epa.gov/cpcat) database of information on chemicals mapped to "use categories" describing the usage or function of the chemical. CPCat was created by combining multiple and diverse sources of data on consumer- and industrial-process based chemical uses from regulatory agencies, manufacturers, and retailers in various countries. The database uses a controlled vocabulary of 833 terms and a novel nomenclature to capture and streamline descriptors of chemical use for 43,596 chemicals from the various sources. Examples of potential applications of CPCat are provided, including identifying chemicals to which children may be exposed and to support prioritization of chemicals for toxicity screening. CPCat is expected to be a valuable resource for regulators, risk assessors, and exposure scientists to identify potential sources of human exposures and exposure pathways, particularly for use in high-throughput chemical exposure assessment.

  5. Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis

    Science.gov (United States)

    Brimhall, George H.; Dietrich, William E.

    1987-03-01

    Relations characterizing the chemical, physical, and mechanical changes resulting from metasomatic hydrochemical processes are developed using mass balance models which formally link chemical composition to bulk density, mineral density, volumetric properties, porosity, and amount of deformation (strain). Rigorous analysis of aqueous solute transport effects is then made possible in a variety of porous media flow environments including chemical weathering, pedogenesis (soil formation), diagenesis, ore deposition and enrichment, and metamorphism. Application of these linear constitutive relations to chemical weathering profiles shows that immobile and locally mobile chemical elements, with masses conserved on the scale of soil profiles, can be accurately identified from analysis of appropriate data arrays and then used as natural geochemical tracers to infer the nature and extent of hydrochemical weathering processes and volume changes during pedogenesis. Assumptions commonly made in the past about the supposed immobility of certain elements, e.g., Ti and Zr, become unnecessary. Quantitative differentiation between the effects of residual and supergene fractionation is then easily made. These methods are applied to Ni-rich laterites developed by weathering of ultramafic rocks, showing that during ordinary residual enrichment, Ni is concentrated by as much as 4× protolith peridotite concentrations. This occurs simply by silicate mineral dissolution and removal of chemical elements other than Ni ( e.g., Mg) with a corresponding reduction in saprolite density and increase in bulk porosity without significant deformation. In contrast, laterites with mineable concentrations of Ni which are similarly undeformed (such as the Nickel Mountain Mine in Riddle, Oregon) have experienced, in addition to residual enrichment, strong supergene enrichment by fractionation of ore elements between a leached zone from which Ni is extracted and a complementary enriched zone positioned

  6. Long term assurance of supply of uranium enrichment

    International Nuclear Information System (INIS)

    1978-01-01

    After elaborating a number of key questions on uranium enrichment, the representatives of 10 countries and of the EC commission present their answers. Attention is paid to the assurance of uranium supply, to uranium enrichment, market trends and flexibility in enrichment agreements

  7. GOMA: functional enrichment analysis tool based on GO modules

    Institute of Scientific and Technical Information of China (English)

    Qiang Huang; Ling-Yun Wu; Yong Wang; Xiang-Sun Zhang

    2013-01-01

    Analyzing the function of gene sets is a critical step in interpreting the results of high-throughput experiments in systems biology.A variety of enrichment analysis tools have been developed in recent years,but most output a long list of significantly enriched terms that are often redundant,making it difficult to extract the most meaningful functions.In this paper,we present GOMA,a novel enrichment analysis method based on the new concept of enriched functional Gene Ontology (GO) modules.With this method,we systematically revealed functional GO modules,i.e.,groups of functionally similar GO terms,via an optimization model and then ranked them by enrichment scores.Our new method simplifies enrichment analysis results by reducing redundancy,thereby preventing inconsistent enrichment results among functionally similar terms and providing more biologically meaningful results.

  8. Silver surface enrichment of silver-copper alloys: a limitation for the analysis of ancient silver coins by surface techniques

    International Nuclear Information System (INIS)

    Beck, L.; Bosonnet, S.; Reveillon, S.; Eliot, D.; Pilon, F.

    2004-01-01

    The surface enrichment of archaeological silver-copper alloys has been recognized for many years. However, the origin of this enrichment is not well defined and many hypotheses have been put forward to account for this behaviour: segregation of the components during casting, deliberate thermal and/or chemical post-treatment, abrasion or corrosion. Among the hypotheses mentioned above, we have focused our study on the first step of coin manufacturing. Replications of silver-copper standards of various compositions ranging from 30% to 80% Ag, reflecting the composition of silver blanks, have been produced. Metallographic examination, PIXE and SEM-EDS have been used for the characterization of each sample. A model of the direct enrichment has been established. This model allows us to propose a relationship between the surface composition and the silver content of the core. Comparison with data of Roman coins from the Roman site of Cha-hat teaubleau (France) and from the literature and consequences for the analyses of ancient coins by surface methods are presented

  9. Enrichment of light hydrocarbon mixture

    Science.gov (United States)

    Yang,; Dali, [Los Alamos, NM; Devlin, David [Santa Fe, NM; Barbero, Robert S [Santa Cruz, NM; Carrera, Martin E [Naperville, IL; Colling, Craig W [Warrenville, IL

    2010-08-10

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  10. Uranium enrichment capacity: public versus private ownership

    International Nuclear Information System (INIS)

    Fraser, J.T.

    1977-01-01

    Continual growth of conventional nuclear capacity requires an assured supply of enriched uranium and, hence, potential expansion of domestic uranium enrichment capacity. The question of ownership of new enrichment capacity, i.e., public or private, entails not only the social-opportunity costs of alternative investments but also technical parameters of uranium utilization and advanced reactor development. Inclusion of risk preferences in both the public and private sectors produces interesting results in terms of optimal investment strategies with respect to choice of technology and scale of investment. Utilization of a nuclear fuel cycle requirements process model allows explicit specification of production technology. Integration of process model output with a least-cost investment model permits flexibility in parametric analysis. Results indicate minimum incentive for Government subsidy of a private enrichment sector through 2000 given moderate to low nuclear growth assumptions. The long-run scenario, to 2020, exhibits potentially greater incentives for private enrichment investment

  11. Evaluation of the uranium enrichment demonstration plant project

    International Nuclear Information System (INIS)

    Sugitsue, Noritake

    2001-01-01

    In this report, the organization system of the uranium enrichment business is evaluated, based on the operation of the uranium enrichment demonstration plant. As a result, in uranium enrichment technology development or business, it was acknowledged that maintenance of the organization which has the Trinity of a research/engineering/operation was necessary in an industrialization stage by exceptional R and D cycle. Japan Nuclear Fuel Ltd. (JNFL) set up the Rokkashomura Aomori Uranium Enrichment Research and Development Center in November 2000. As a result, the system that company directly engaged in engineering development was prepared. And results obtained in this place is expected toward certain establishment of the uranium enrichment business of Japan. (author)

  12. Uranium enrichment: a vital new industry

    International Nuclear Information System (INIS)

    1975-10-01

    The energy problem facing the nation and the need for nuclear power are pointed out. Uranium enrichment and the demand for it are discussed. Reasons for, and obstacles to, private enrichment are outlined. The President's plan (including the Nuclear Fuel Assurance Act) is summarized

  13. Chemical Evolution of a Protoplanetary Disk

    Science.gov (United States)

    Semenov, Dmitry A.

    2011-12-01

    In this paper we review recent progress in our understanding of the chemical evolution of protoplanetary disks. Current observational constraints and theoretical modeling on the chemical composition of gas and dust in these systems are presented. Strong variations of temperature, density, high-energy radiation intensities in these disks, both radially and vertically, result in a peculiar disk chemical structure, where a variety of processes are active. In hot, dilute and heavily irradiated atmosphere only the most photostable simple radicals and atoms and atomic ions exist, formed by gas-phase processes. Beneath the atmosphere a partly UV-shielded, warm molecular layer is located, where high-energy radiation drives rich ion-molecule and radical-radical chemistry, both in the gas phase and on dust surfaces. In a cold, dense, dark disk midplane many molecules are frozen out, forming thick icy mantles where surface chemistry is active and where complex polyatomic (organic) species are synthesized. Dynamical processes affect disk chemical composition by enriching it in abundances of complex species produced via slow surface processes, which will become detectable with ALMA.

  14. The Helikon technique for isotope enrichment

    International Nuclear Information System (INIS)

    Haarhoff, P.C.

    1976-11-01

    The separating element employed in the UCOR process for uranium enrichment has an enriched stream which is much smaller than the depleted stream. To deal with this small cut and to exploit the full potential of the process, a new cascade technique has been developed, the so-called helikon technique. It is based on the principle that an axial flow compressor can simultaneously compress a number of streams of different isotopic composition, which flow through it in parallel, without any significant mixing between them. The technique makes it possible to achieve the desired enrichment with a relatively small number of separating units, by making the best use of the high enrichment factor available. A further feature of the helikon technique is that a module yields an enrichment factor which is not constant, but can vary. In this way a cascade can be built up from modules of a fixed size, which is a great advantage when compared to conventional cascade arrangements where several unit sizes are required. A general theoretical treatment of the helikon technique is given and the similarity between helikon and conventional cascades is pointed out. Practical helikon cascades are subsequently discussed on the basis of the UCOR process

  15. Preparation of carbon dioxide adsorbents from the chemical activation of urea-formaldehyde and melamine-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Drage; A. Arenillas; K.M. Smith; C. Pevida; S. Piippo; C.E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2007-01-15

    Adsorption is considered to be one of the more promising technologies for the capture of CO{sub 2} from flue gases. In general, nitrogen enrichment is reported to be effective in enhancing the specific adsorbent-adsorbate interaction for CO{sub 2}. Nitrogen enriched carbons were produced from urea-formaldehyde and melamine-formaldehyde resins polymerised in the presence of K{sub 2}CO{sub 3} as a chemical activation agent, with activation undertaken over a range of temperatures. CO{sub 2} adsorption capacity was determined to be dependent upon both textural properties and more importantly nitrogen functionality. Adsorbents capable of capturing above 8 wt.% CO{sub 2} at 25{sup o}C were produced from the chemical activation of urea-formaldehyde resin at 500{sup o}C. Chemical activation seems to produce more effective adsorbents than CO{sub 2} activation. 29 refs., 4 figs., 3 tabs.

  16. Phosphopeptide Enrichment by Covalent Chromatography after Derivatization of Protein Digests Immobilized on Reversed-Phase Supports

    Science.gov (United States)

    Nika, Heinz; Nieves, Edward; Hawke, David H.; Angeletti, Ruth Hogue

    2013-01-01

    A rugged sample-preparation method for comprehensive affinity enrichment of phosphopeptides from protein digests has been developed. The method uses a series of chemical reactions to incorporate efficiently and specifically a thiol-functionalized affinity tag into the analyte by barium hydroxide catalyzed β-elimination with Michael addition using 2-aminoethanethiol as nucleophile and subsequent thiolation of the resulting amino group with sulfosuccinimidyl-2-(biotinamido) ethyl-1,3-dithiopropionate. Gentle oxidation of cysteine residues, followed by acetylation of α- and ε-amino groups before these reactions, ensured selectivity of reversible capture of the modified phosphopeptides by covalent chromatography on activated thiol sepharose. The use of C18 reversed-phase supports as a miniaturized reaction bed facilitated optimization of the individual modification steps for throughput and completeness of derivatization. Reagents were exchanged directly on the supports, eliminating sample transfer between the reaction steps and thus, allowing the immobilized analyte to be carried through the multistep reaction scheme with minimal sample loss. The use of this sample-preparation method for phosphopeptide enrichment was demonstrated with low-level amounts of in-gel-digested protein. As applied to tryptic digests of α-S1- and β-casein, the method enabled the enrichment and detection of the phosphorylated peptides contained in the mixture, including the tetraphosphorylated species of β-casein, which has escaped chemical procedures reported previously. The isolates proved highly suitable for mapping the sites of phosphorylation by collisionally induced dissociation. β-Elimination, with consecutive Michael addition, expanded the use of the solid-phase-based enrichment strategy to phosphothreonyl peptides and to phosphoseryl/phosphothreonyl peptides derived from proline-directed kinase substrates and to their O-sulfono- and O-linked β-N-acetylglucosamine (O

  17. Enrichment of Probiotic Fermented Milk with Green Banana Pulp: Characterization Microbiological, Physicochemical and Sensory

    Directory of Open Access Journals (Sweden)

    Carolina de Oliveira Vogado

    2018-03-01

    Full Text Available The aims of this study were (i to evaluate the growth kinetic of L. paracasei LBC 81 in fermented milks enriched with green banana pulp (GBP; (ii to evaluate the effect of the incorporation of GBP on the chemical composition and the sensory acceptance; and (iii to study the viability of the probiotic and technological properties during refrigerated storage. The amount of GBP used were 3.0, 6.0 and 9.0 g/100 g. The results show that the higher the concentration of GBP added, the shorter the time taken to reach pH 4.6. It was observed that the incorporation of GBP did not affect negatively the viability of L. paracasei LBC 81 during storage. The fermented milk elaborated with 6.0 g/100 g of GBP was the most accepted. The present study indicates that the enrichment of fermented milk with GBP favors the stability of the probiotic strain, L. paracasei LBC 81 during storage.

  18. Effects of chronic iTBS-rTMS and enriched environment on visual cortex early critical period and visual pattern discrimination in dark-reared rats.

    Science.gov (United States)

    Castillo-Padilla, Diana V; Funke, Klaus

    2016-01-01

    Early cortical critical period resembles a state of enhanced neuronal plasticity enabling the establishment of specific neuronal connections during first sensory experience. Visual performance with regard to pattern discrimination is impaired if the cortex is deprived from visual input during the critical period. We wondered how unspecific activation of the visual cortex before closure of the critical period using repetitive transcranial magnetic stimulation (rTMS) could affect the critical period and the visual performance of the experimental animals. Would it cause premature closure of the plastic state and thus worsen experience-dependent visual performance, or would it be able to preserve plasticity? Effects of intermittent theta-burst stimulation (iTBS) were compared with those of an enriched environment (EE) during dark-rearing (DR) from birth. Rats dark-reared in a standard cage showed poor improvement in a visual pattern discrimination task, while rats housed in EE or treated with iTBS showed a performance indistinguishable from rats reared in normal light/dark cycle. The behavioral effects were accompanied by correlated changes in the expression of brain-derived neurotrophic factor (BDNF) and atypical PKC (PKCζ/PKMζ), two factors controlling stabilization of synaptic potentiation. It appears that not only nonvisual sensory activity and exercise but also cortical activation induced by rTMS has the potential to alleviate the effects of DR on cortical development, most likely due to stimulation of BDNF synthesis and release. As we showed previously, iTBS reduced the expression of parvalbumin in inhibitory cortical interneurons, indicating that modulation of the activity of fast-spiking interneurons contributes to the observed effects of iTBS. © 2015 Wiley Periodicals, Inc.

  19. Sub-micrometer-scale patterning on Zr-based metallic glass using focused ion beam irradiation and chemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Kawasegi, Noritaka [Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Morita, Noboru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Yamada, Shigeru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Takano, Noboru [Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Oyama, Tatsuo [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Ashida, Kiwamu [Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Momota, Sadao [Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, 185 Tosayamada, Kochi 782-8502 (Japan); Taniguchi, Jun [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Miyamoto, Iwao [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Ofune, Hitoshi [YKK Corporation, 200 Yoshida, Kurobe, Toyama 938-8601 (Japan)

    2007-09-19

    This report describes a method of sub-micrometer-scale rapid patterning on a Zr-based metallic glass surface using a combination of focused ion beam irradiation and wet chemical etching. We found that a Zr-based metallic glass surface irradiated with Ga{sup +} ions could be selectively etched; a concave structure with a width and depth of several tens to hundreds of nanometers rapidly formed in the irradiated area. Moreover, we determined that the etching was enhanced by the presence of Ga{sup +} ions rather than a change in the crystal structure, and the structure could be fabricated while the substrate remained amorphous. The shape of the structure was principally a function of the dose and the etch time.

  20. 31 CFR 540.306 - Highly Enriched Uranium (HEU).

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Highly Enriched Uranium (HEU). 540...) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.306 Highly Enriched Uranium (HEU). The term highly...

  1. Regional-to-Urban Enviro-HIRLAM Downscaling for Meteorological and Chemical Patterns over Chinese Megacities

    Science.gov (United States)

    Mahura, Alexander; Nuterman, Roman; Gonzalez-Aparicio, Iratxe; Amstrup, Bjarne; Baklanov, Alexander; Yang, Xiaohua; Nielsen, Kristian

    2015-04-01

    Due to strong economic growth in the past decades, air pollution became a serious problem in megacities and major industrial agglomerations of China. So, information on air quality in these urbanized areas is important for population. In particular, the metropolitan areas of Shanghai, Beijing, and Pearl River Delta are well known as main regions with serious air pollution issues. One of the aims of the EU FP7 MarcoPolo project is to improve existing regional-meso-urban/city scale air quality forecasts using improved emission inventories and to validate modelling results using satellite and ground-based measurements. The Enviro-HIRLAM (Environment - HIgh Resolution Limited Area Model) adapted for the Shanghai region of China is applied for forecasting. The model is urbanized using the Building Effects Parameterization module, which describes different types of urban districts such as industrial commercial, city center, high density and residential with its own characteristics. For sensitivity studies, the model was run in downscaling chain from regional-to-urban scales at subsequent horizontal resolutions of 15-5-2.5 km for selected dates with elevated pollution levels and unfavorable meteorological conditions. For these dates, the effects of urbanization are analyzed for atmospheric transport, dispersion, deposition, and chemical transformations. The evaluation of formation and development of meteorological and chemical/aerosol patterns due to influence of the urban areas is performed. The impact of selected (in a model domain) megacities of China is estimated on regional-to-urban scales, as well as relationship between air pollution and meteorology are studied.

  2. Chemical composition of extremely metal-poor stars in the Sextans dwarf spheroidal galaxy

    OpenAIRE

    Aoki, W.; Arimoto, N.; Sadakane, K.; Tolstoy, E.; Battaglia, G.; Jablonka, P.; Shetrone, M.; Letarte, B.; Irwin, M.; Hill, V.; Francois, P.; Venn, K.; Primas, F.; Helmi, A.; Kaufer, A.

    2009-01-01

    Context. Individual stars in dwarf spheroidal galaxies around the Milky Way Galaxy have been studied both photometrically and spectroscopically. Extremely metal-poor stars among them are very valuable because they should record the early enrichment in the Local Group. However, our understanding of these stars is very limited because detailed chemical abundance measurements are needed from high resolution spectroscopy. Aims. To constrain the formation and chemical evolution of dwarf galaxi...

  3. Comparative studies on mitochondria isolated from neuron-enriched and glia-enriched fractions of rabbit and beef brain.

    Science.gov (United States)

    Hamberger, A; Blomstrand, C; Lehninger, A L

    1970-05-01

    Fractions enriched in neuronal and glial cells were obtained from dispersions of whole beef brain and rabbit cerebral cortex by large-scale density gradient centrifugation procedures. The fractions were characterized by appropriate microscopic observation. Mitochondria were then isolated from these fractions by differential centrifugation of their homogenates. The two different types of mitochondria were characterized with respect to certain enzyme activities, respiratory rate, rate of protein synthesis, and their buoyant density in sucrose gradients. The mitochondria from the neuron-enriched fraction were distinguished by a higher rate of incorporation of amino acids into protein, higher cytochrome oxidase activity, and a higher buoyant density in sucrose density gradients. Mitochondria from the glia-enriched fraction showed relatively high monoamine oxidase and Na(+)- and K(+)-stimulated ATPase activities. The rates of oxidation of various substrates and the acceptor control ratios did not differ appreciably between the two types of mitochondria. The difference in the buoyant density of mitochondria isolated from the neuron-enriched and glia-enriched cell fractions was utilized in attempts to separate neuronal and glial mitochondria from the mixed mitochondria obtained from whole brain homogenates in shallow sucrose gradients. The appearance of two peaks of cytochrome oxidase, monoamine oxidase, and protein concentration in such gradients shows the potential feasibility of such an approach.

  4. Seasonality of Leaf Carbon Isotopic Composition and Leaf Water Isotopic Enrichment in a Mixed Evergreen Forest in Southern California

    Science.gov (United States)

    Santiago, L. S.; Sickman, J. O.; Goulden, M.; DeVan, C.; Pasquini, S. C.; Pivovaroff, A. L.

    2011-12-01

    Leaf carbon isotopic composition and leaf water isotopic enrichment reflect physiological processes and are important for linking local and regional scale processes to global patterns. We investigated how seasonality affects the isotopic composition of bulk leaf carbon, leaf sugar carbon, and leaf water hydrogen under a Mediterranean climate. Leaf and stem samples were collected monthly from four tree species (Calocedrus decurrens, Pinus lambertiana, Pinus ponderosa, and Quercus chrysolepis) at the James San Jacinto Mountain Reserve in southern California. Mean monthly bulk leaf carbon isotopic composition varied from -34.5 % in P. ponderosa to -24.7 % in P. lambertiana and became more depleted in 13C from the spring to the summer. Mean monthly leaf sugar varied from -29.3 % in P. ponderosa to -21.8 % in P. lambertiana and was enriched in 13C during the winter, spring and autumn, but depleted during the mid-summer. Leaf water hydrogen isotopic composition was 28.4 to 68.8 % more enriched in deuterium than source water and this enrichment was greater as seasonal drought progressed. These data indicate that leaf carbon and leaf water hydrogen isotopic composition provide sensitive measures that connect plant physiological processes to short-term climatic variability.

  5. Enriched uranium recovery flowsheet improvements

    International Nuclear Information System (INIS)

    Holt, D.L.

    1986-01-01

    Savannah River uses 7.5% TBP to recover and purify enriched uranium. Adequate decontamination from fission products is necessary to reduce personnel exposure and to ensure that the enriched uranium product meets specifications. Initial decontamination of the enriched uranium from the fission products is carried out in the 1A bank, 16 stages of mixer-settlers. Separation of the enriched uranium from the fission product, 95 Zr, has been adequate, but excessive solvent degradation caused by the long phase contact times in the mixer-settlers has limited the 95 Zr decontamination factor (DF). An experimental program is investigating the replacement of the current 1A bank with either centrifugal contactors or a combination of centrifugal contactors and mixer-settlers. Experimental work completed has compared laboratory-scale centrifugal contactors and mixer-settlers for 95 Zr removal efficiencies. Feed solutions spiked with actual plant solutions were used. The 95 Zr DF was significantly better in the mixer-settlers than in the centrifugal contactors. As a result of this experimental study, a hybrid equipment flowsheet has been proposed for plant use. The hybrid equipment flowsheet combines the advantages of both types of solvent extraction equipment. Centrifugal contactors would be utilized in the extraction and initial scrub sections, followed by additional scrub stages of mixer-settlers

  6. Use of starter cultures of lactic acid bacteria and yeasts as inoculum enrichment for the production of gowé, a sour beverage from Benin

    DEFF Research Database (Denmark)

    Vieira-Dalodé, G.; Madodé, Y.E.; Hounhouigan, J.

    2008-01-01

    Lactobacillus fermentum, Weissella confusa, Kluyveromyces marxianus and Pichia anomala, previously isolated during natural fermentation of traditional gowé, were tested as inoculum enrichment for controlled fermentation of gowé. The final product was subjected to chemical analysis and sensory eva...

  7. Stable isotope enrichment by thermal diffusion

    International Nuclear Information System (INIS)

    Vasaru, Gheorghe

    2003-01-01

    Thermal diffusion (TD) in both gaseous and liquid phase has been the subject of extensive experimental and theoretical investigations, especially after the invention by K. Clusius and G. Dickel of the thermal diffusion column, sixty years ago. This paper gives a brief overview of the most important applications and developments of this transport phenomenon for enrichment of 13 C and of some noble gases isotopes in our institute. The results of calculations of the transport coefficients H and K for a concentric tube type TD column, operated with methane as process gas, are presented. Static separation factor at equilibrium vs gas pressure has been calculated for various molecular models. The experimental separation factors for different gas pressure were found to be consistent with those calculated for the inverse power repulsion model and the Lennard-Jones model. The most important characteristics of a seven-stage cascade consisting of 19 TD columns of concentric tube type are given. This system has been constructed and successfully operated at a temperature of 673 K and produces an enrichment of methane of natural isotopic 13 C abundance, up to the concentration of 25% 13 CH 4 . Enrichment of the noble gases isotopes implies: - a . Enrichment of 20 Ne and 22 Ne in a eight-stage cascade consisting of 8 TD columns; - b. enrichment of 46 Ar in a seven-stage cascade consisting of TD columns and finally; - c. enrichment of 78 Kr and 86 Kr in a fifteen-stage cascade, consisting of 35 TD columns. For all these installations we have adopted TD columns of hot wire type (4 m in length), operated at a temperature of 1073 K. (author)

  8. MICROBIOLOGICAL AND NUTRITIONAL QUALITY OF WARANKASHI ENRICHED BREAD

    Directory of Open Access Journals (Sweden)

    O. E. Dudu

    2012-08-01

    Full Text Available The study was carried out to determine the microbiological and nutritional quality, organoleptic, rheological and textural effect as well as the effect on the shelf life of wheat bread enriched with West African cottage cheese (warankashi at different substitution levels (1 %, 3 % and 5 %. The protein and fat content of wheat bread significantly increased but carbohydrate levels decreased significantly as enrichment with Warankashi increased. The amino acid profile of the wheat bread increased with increasing enrichment. The incorporation of Warankashi into wheat flour affected the rheological and textural properties of wheat flour; the rate of water absorption of the wheat flour decreased as Warankashi incorporation levels increased. Also, the dough stability time of the enriched flours was lesser than that of the wheat flour. The 3 % enrichment level had the highest dough consistency (520 BU. The extensibility of 1 % and 3 % wara bread dough were the same while that of wheat flour bread and 5 % Warankashi were the same. The 3 % wara bread dough had the highest resistance to extension. Shelf life of the bread remained unaffected by Warankashi incorporation but the rate of bacteria and fungi (yeast and mould growth decreased significantly (P < 0.05 as enrichment levels increased. There was no significant difference between the organoleptic properties of wheat bread to that of the enriched breads but the 3 % Warankshi enriched bread had the highest consumer acceptability.

  9. Enrichment of glioma stem cell-like cells on 3D porous scaffolds composed of different extracellular matrix.

    Science.gov (United States)

    Wang, Xuanzhi; Dai, Xingliang; Zhang, Xinzhi; Li, Xinda; Xu, Tao; Lan, Qing

    2018-04-15

    Cancer stem cells (CSCs), being tumor-initiating with self-renewal capacity and heterogeneity, are most likely the cause of tumor resistance, reoccurrence and metastasis. To further investigate the role of CSCs in tumor biology, there is a need to develop an effective culture system to grow, maintain and enrich CSCs. Three-dimensional (3D) cell culture model has been widely used in tumor research and drug screening. Recently, researchers have begun to utilize 3D models to culture cancer cells for CSCs enrichment. In this study, glioma cell line was cultured with 3D porous chitosan (CS) scaffolds or chitosan-hyaluronic acid (CS-HA) scaffolds to explore the possibility of glioma stem cells (GSCs)-like cells enrichment, to study the morphology, gene expression, and in vivo tumorigenicity of 3D scaffolds cells, and to compare results to 2D controls. Results showed that glioma cells on both CS and CS-HA scaffolds could form tumor cell spheroids and increased the expression of GSCs biomarkers compared to conventional 2D monolayers. Furthermore, cells in CS-HA scaffolds had higher expression levels of epithelial-to-mesenchymal transition (EMT)-related gene. Specifically, the in vivo tumorigenicity capability of CS-HA scaffold cultured cells was greater than 2D cells or CS scaffold cultured cells. It is indicated that the chemical composition of scaffold plays an important role in the enrichment of CSCs. Our results suggest that CS-HA scaffolds have a better capability to enrich GSCs-like cells and can serve as a simple and effective way to cultivate and enrich CSCs in vitro to support the study of CSCs biology and development of novel anti-cancer therapies. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Safety aspects of gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Hansen, A.H.

    1987-01-01

    Uranium enrichment by gas centrifuge is a commercially proven, viable technology. Gas centrifuge enrichment plant operations pose hazards that are also found in other industries as well as unique hazards as a result of processing and handling uranium hexafluoride and the handling of enriched uranium. Hazards also found in other industries included those posed by the use of high-speed rotating equipment and equipment handling by use of heavy-duty cranes. Hazards from high-speed rotating equipment are associated with the operation of the gas centrifuges themselves and with the operation of the uranium hexafluoride compressors in the tail withdrawal system. These and related hazards are discussed. It is included that commercial gas centrifuge enrichment plants have been designed to operate safely

  11. Geochemical and rare earth elements distribution pattern in gaiman F M.phosphatic levels, Chubu t, Argentina

    International Nuclear Information System (INIS)

    Castro, L.; Fazio, A.; Tourn, S.; Scasso, R.

    2004-01-01

    Phosphatic concretions in the Early Miocene marine sediments of the Gaiman Formation (Miocene) were analyzed for rare earth elements (REE), in order to discuss their pattern in the context of paleoenvironmental interpretations. P2O5 in concretions is between 15,61 to 21,82%. Two types of concretions are found: Type 1 represented by in situ ones developed within transgressive-early highstand system tracts which shows little evidence for significant transportation, and Type 2 related to reworking, winnowing and mechanical concentration of resistant particles. Type 1 exhibits higher REE/P ratios and a significant enrichment in HREE than Type 2. The REE pattern in both shows a slight depletion in LREE with a weak Ce anomaly (-0.08 to 0.04), and an enrichment in high rare earth elements, in comparison to the a verage shale. Their mean content in REE (915 ppm) and Y (500 ppm) doubles the worldwide phosphorite average (462 ppm and 275 ppm). No significant correlation is found between REEs and P2O5. On the other hand, HREE enrichment (Lu/Ce) increases with the REEs bulk content. The pattern is consistent with shallow water inner shelf marine environment which is also suggested by sedimentological and paleontological evidence [es

  12. Uranium enrichment: an evolving market

    International Nuclear Information System (INIS)

    Longenecker, J.; Witzel, R.

    1997-01-01

    With over half of the world uranium enrichment market uncommitted to any supplier early in the next century, competition is certain to be fierce. In the meantime the outlood remains unclear, with the market dominated by a number of developments -privatisation of the United States Enrichment Corp (USEC), increasing availability of Russian and US military inventories, the deployment of advanced technology and the closure of nuclear power plants due to deregulation. (author)

  13. A theory of surface enrichment in ordered alloys

    NARCIS (Netherlands)

    Santen, van R.A.; Sachtler, W.M.H.

    1974-01-01

    A simple theory was developed to explain exptl. data on surface enrichment in Pt3Sn. The computed surface enrichment is in accord with exptl. findings. The theory predicts that in the Pt3Sn system enrichment occurs by interchange of atoms of the element with the lower heat of sublimation from the

  14. Detection of uranium enrichment activities using environmental monitoring techniques

    International Nuclear Information System (INIS)

    Belew, W.L.; Carter, J.A.; Smith, D.H.; Walker, R.L.

    1993-01-01

    Uranium enrichment processes have the capability of producing weapons-grade material in the form of highly enriched uranium. Thus, detection of undeclared uranium enrichment activities is an international safeguards concern. The uranium separation technologies currently in use employ UF 6 gas as a separation medium, and trace quantities of enriched uranium are inevitably released to the environment from these facilities. The isotopic content of uranium in the vegetation, soil, and water near the plant site will be altered by these releases and can provide a signature for detecting the presence of enriched uranium activities. This paper discusses environmental sampling and analytical procedures that have been used for the detection of uranium enrichment facilities and possible safeguards applications of these techniques

  15. The enriched chromium neutrino source for GALLEX

    International Nuclear Information System (INIS)

    Hartmann, F.X.; Hahn, R.L.

    1991-01-01

    The preparation and study of an intense source of neutrinos in the form of neutron irradiated materials which are enriched in Cr-50 for use in the GALLEX solar neutrino experiment are discussed. Chromyl fluoride gas is enriched in the Cr-50 isotope by gas centrifugation and subsequently converted to a very stable form of chromium oxide. The results of neutron activation analyses of such chromium samples indicate low levels of any long-lived activities, but show that short-lived activities, in particular Na-24, may be of concern. These results show that irradiating chromium oxide enriched in Cr-50 is preferable to irradiating either natural chromium or argon gas as a means of producing a neutrino source to calibrate the GALLEX detector. These results of the impurity level analysis of the enriched chromyl fluoride gas and its conversion to the oxide are also of interest to work in progress by other members of the Collaboration investigating an alternative conversion of the enriched gas to chromium metal. 35 refs., 12 figs., 5 tabs

  16. High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

    Science.gov (United States)

    Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

    2015-12-01

    Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm2. The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs.

  17. How is uranium supply affecting enrichment?

    International Nuclear Information System (INIS)

    Steve Kidd

    2007-01-01

    As a result of the enlivened uranium market, momentum has in turn picked up in the enrichment sector. What are the consequences of higher uranium prices? There is, of course, a link between uranium and enrichment supply to the extent that they are at least partial substitutes. On the enrichment supply side, the most obvious feature is the gradual replacement of the old gas diffusion facilities of Usec in the USA and EURODIF in France with more modern and economical centrifuge plants. Assuming Usec can overcome the financing and technical issues surrounding its plans, the last gas diffusion capacity should disappear around 2015 and the entire enrichment market should then be using centrifuges. On the commercial side, the key anticipated developments are mostly in Russia. Although there should still continue to be substantial quantities of surplus Russian HEU available for down blending in the period beyond 2013, it is now reasonable to expect that it will be mostly consumed by internal needs, to fuel Russian-origin reactors both at home and in export markets such as China and India. Finally, as a key sensitive area for the non-proliferation of nuclear weapons, the enrichment sector is likely to be a central point of the new international arrangements which must be developed to support a buoyant nuclear sector throughout this century.

  18. Fructose decomposition kinetics in organic acids-enriched high temperature liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yinghua; Lu, Xiuyang; Yuan, Lei; Liu, Xin [Department of Chemical and Biochemical Engineering, Zhejiang University, Zheda Road 38, Hangzhou 310027, Zhejiang (China)

    2009-09-15

    Biomass continues to be an important candidate as a renewable resource for energy, chemicals, and feedstock. Decomposition of biomass in high temperature liquid water is a promising technique for producing industrially important chemicals such as 5-hydroxymethylfurfural (5-HMF), furfural, levulinic acid with high efficiency. Hexose, which is the hydrolysis product of cellulose, will be one of the most important starting chemicals in the coming society that is highly dependent on biomass. Taking fructose as a model compound, its decomposition kinetics in organic acids-enriched high temperature liquid water was studied in the temperature range from 180 C to 220 C under the pressure of 10 MPa to further improve reaction rate and selectivity of the decomposition reactions. The results showed that the reaction rate is greatly enhanced with the addition of organic acids, especially formic acid. The effects of temperature, residence time, organic acids and their concentrations on the conversion of fructose and yield of 5-HMF were investigated. The evaluated apparent activation energies of fructose decomposition are 126.8 {+-} 3.3 kJ mol{sup -1} without any catalyst, 112.0 {+-} 13.7 kJ mol{sup -1} catalyzed with formic acid, and 125.6 {+-} 3.8 kJ mol{sup -1} catalyzed with acetic acid, respectively, which shows no significant difference. (author)

  19. Toward a predictive theory for environmental enrichment.

    Science.gov (United States)

    Watters, Jason V

    2009-11-01

    There have been many applications of and successes with environmental enrichment for captive animals. The theoretical spine upon which much enrichment work hangs largely describes why enrichment should work. Yet, there remains no clear understanding of how enrichment should be applied to achieve the most beneficial results. This lack of understanding may stem in part from the assumptions that underlie the application of enrichment by practitioners. These assumptions are derived from an understanding that giving animals choice and control in their environment stimulates their motivation to perform behaviors that may indicate a heightened state of well-being. Learning theory provides a means to question the manner in which these constructs are routinely applied, and converting learning theory's findings to optimality predictions suggests a particularly vexing paradox-that motivation to perform appears to be maintained best when acquiring a payoff for expressing the behavior is uncertain. This effect occurs even when the actual value of the payoff is the same for all schedules of certainty of payoff acquisition. The paradox can be resolved by invoking rewards of an alternative type, such as cognitive rewards, or through an understanding of how the average payoff changes with changes in the probability of reward. This model, with measures of the average change of the payoff, suggests testable scenarios by which practitioners can measure the quality of environmental uncertainty in enrichment programs.

  20. The isotopic enrichment of uranium in 1979

    International Nuclear Information System (INIS)

    Baron, M.

    1979-01-01

    The Eurodif uranium enrichment plant built on the Tricastin site is described. The uranium isotope separation plants in service abroad are presented. The main characteristics of the international enrichment market are defined [fr