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Sample records for aldol condensation estrutura

  1. A Green Enantioselective Aldol Condensation for the Undergraduate Organic Laboratory

    Science.gov (United States)

    Bennett, George D.

    2006-01-01

    A number of laboratory exercises for the organic chemistry curriculum that emphasize enantioselective synthesis of the aldol condensation which involves the proline-catalyzed condensation between acetone and isobutyraldehyde are explored. The experiment illustrates some of the trade-offs involved in green chemistry like the use of acetone in large…

  2. Aldol condensation of furfural and acetone on zeolites

    Czech Academy of Sciences Publication Activity Database

    Kikhtyanin, O.; Kelbichová, V.; Vitvarová, Dana; Kubů, Martin; Kubička, D.

    2014-01-01

    Roč. 227, MAY 2014 (2014), s. 154-162 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : aldol condensation * oligomerization * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  3. Activated hydrotalcites as solid base catalysts in aldol condensations

    NARCIS (Netherlands)

    Roelofs, J.C.A.A.

    2001-01-01

    The development of new catalytic materials and routes to replace environmentally unacceptable processes in the fine chemical industry is emerging due to stringent legislation. Replacement of currently applied alkali bases in liquid-phase aldol condensations can result in diminishing of waste water

  4. Molecular shape selectivity of hydrotalcite in mixed aldol condensations of aldehydes and ketones

    Czech Academy of Sciences Publication Activity Database

    Červený, J.; Šplíchalová, J.; Kačer, P.; Kovanda, F.; Kuzma, Marek; Červený, L.

    2008-01-01

    Roč. 285, 1-2 (2008), s. 150-154 ISSN 1381-1169 R&D Projects: GA ČR GA104/07/1239 Institutional research plan: CEZ:AV0Z50200510 Keywords : hydrocalcite * aldol condensation * molecular modeling Subject RIV: EE - Microbiology, Virology Impact factor: 2.814, year: 2008

  5. Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

    NARCIS (Netherlands)

    Hernández-giménez, Ana M.; Ruiz-martínez, Javier; Puértolas, Begoña; Pérez-ramírez, Javier; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2017-01-01

    The gas-phase aldol condensation of propanal, taken as model for the aldehyde components in bio-oils, has been studied with a combined operando set-up allowing to perform FT-IR & UV–Vis diffuse reflectance spectroscopy (DRS) with on-line mass spectrometry (MS). The selected solid base catalysts, a

  6. A green, inexpensive and efficient organocatalyzed procedure for aqueous aldol condensations

    Energy Technology Data Exchange (ETDEWEB)

    Abaee, M. Saeed; Mojtahedi, Mohammad M.; Forghani, Soudabeh; Sharifi, Roholah [Chemistry and Chemical Engineering Research Center of Iran, Tehran (Iran, Islamic Republic of). Faculty of Organic Chemistry and Natural Products; Ghandchi, Nafiseh M. [Islamic Azad University, Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Forouzani, Mehdi; Chaharnazm, Behnam [Payam Noor University, Sari (Iran, Islamic Republic of)

    2009-07-01

    A facile and general procedure is presented for diethylamine-catalyzed double crossed aldol condensation of cyclic ketones with various aromatic aldehydes under aqueous conditions. Excellent yields of 3,5-bisarylmethylidenes of homocyclic and heterocyclic ketones are achieved in a one-pot procedure. Furthermore, the methodology is efficiently applied to the synthesis of chalcones from their corresponding methyl ketones. In the majority of the cases studied, products precipitate from the reaction mixtures and the medium is recycled in subsequent several reactions without significant loss of activity. (author)

  7. Boehmite-An Efficient and Recyclable Acid-Base Bifunctional Catalyst for Aldol Condensation Reaction.

    Science.gov (United States)

    Reshma, P C Rajan; Vikneshvaran, Sekar; Velmathi, Sivan

    2018-06-01

    In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3·9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α, β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.

  8. Toward understanding of the role of Lewis acidity in aldol condensation of acetone and furfural using MOF and zeolite catalysts

    Czech Academy of Sciences Publication Activity Database

    Kikhtyanin, O.; Kubička, D.; Čejka, Jiří

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 158-162 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : metal organic framework * aldol condensation * acidic catalysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  9. An overview of dehydration, aldol-condensation and hydrogenation processes for production of liquid alkanes from biomass-derived carbohydrates

    Energy Technology Data Exchange (ETDEWEB)

    Chheda, Juben N.; Dumesic, James A. [University of Wisconsin-Madison, Department of Chemical and Biological Engineering, Madison, WI 53706 (United States)

    2007-05-30

    We present results for the conversion of carbohydrate feedstocks to liquid alkanes by the combination of dehydration, aldol-condensation/hydrogenation, and dehydration/hydrogenation processing. With respect to the first dehydration step, we demonstrate that HMF can be produced in good selectivity from abundantly available polysaccharides (such as inulin, sucrose) containing fructose monomer units using a biphasic batch reactor system. The reaction system can be optimized to achieve good yields to 5-hydroxymethylfurfural (HMF) from fructose by varying the contents of aqueous-phase modifiers such as dimethylsulfoxide (DMSO) and 1-methyl-2-pyrrolidinone (NMP). Regarding the aldol-condensation/hydrogenation step, we present the development of stable, solid base catalysts in aqueous environments. We address the effects of various reaction parameters such as the molar ratio of reactants and temperature on overall product yield for sequential aldol-condensation and hydrogenation steps. Overall, our results show that it is technically possible to convert carbohydrate feedstocks to produce liquid alkanes by the combination of dehydration, aldol-condensation/hydrogenation, and dehydration/hydrogenation processing; however, further optimization of these processes is required to decrease the overall number of separate steps (and reactors) required in this conversion. (author)

  10. Cu/MgAl(2)O(4) as bifunctional catalyst for aldol condensation of 5-hydroxymethylfurfural and selective transfer hydrogenation.

    Science.gov (United States)

    Pupovac, Kristina; Palkovits, Regina

    2013-11-01

    Copper supported on mesoporous magnesium aluminate has been prepared as noble-metal-free solid catalyst for aldol condensation of 5-hydroxymethylfurfural with acetone, followed by hydrogenation of the aldol condensation products. The investigated mesoporous spinels possess high activity as solid-base catalysts. Magnesium aluminate exhibits superior activity compared to zinc and cobalt-based aluminates, reaching full conversion and up to 81 % yield of the 1:1 aldol product. The high activity can be correlated to a higher concentration of basic surface sites on magnesium aluminate. Applying continuous regeneration, the catalysts can be recycled without loss of activity. Focusing on the subsequent hydrogenation of aldol condensation products, Cu/MgAl2 O4 allows a selective hydrogenation and CO bond cleavage, delivering 3-hydroxybutyl-5-methylfuran as the main product with up to 84 % selectivity avoiding ring saturation. Analysis of the hydrogenation activity reveals that the reaction proceeds in the following order: CC>CO>CO cleavage>ring hydrogenation. Comparable activity and selectivity can be also achieved utilizing 2-propanol as solvent in the transfer hydrogenation, providing the possibility for partial recycling of acetone and optimization of the hydrogen management. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Improvement of the stability of basic mixed oxides used as catalysts for aldol condensation of bio-derived compounds by palladium addition

    International Nuclear Information System (INIS)

    Faba, Laura; Díaz, Eva; Ordóñez, Salvador

    2013-01-01

    Aqueous-phase aldol condensation of biomass-derived ketones and aldehydes is a key step in the preparation of fuels and chemicals from renewable resources. Furfural–acetone aldol condensation yielding C 8 and C 13 adducts was studied at 323 K and 1 MPa in a stirred batch reactor. We propose a new strategy for minimizing catalytic deactivation, consisting of modifying catalysts (MgO–ZrO 2 and MgO–Al 2 O 3 ) by Pd addition (2%). This modification slightly changes the morphology and surface chemistry of the supports, leading to changes on the catalysts performance but not reaction mechanism modifications. If condensation is performed in hydrogen atmosphere, the partial hydrogenation of the condensation adducts increases its water solubility, minimizing catalyst deactivation. In that way, the selectivity for C13 adduct decreases only 25% between two successive reaction cycles using Pd/MgO–ZrO 2 catalyst, whereas this decrease is of 90% for the un-doped mixed oxides. These effects are less marked for the MgO–Al 2 O 3 catalyst. Highlights: •Furfural and acetone aldolization on Pd/MgO–ZrO 2 and Pd/MgO–Al 2 O 3 . •Conversion and selectivity towards C8 and C13 low and unstable catalysts. •Aldolization in H 2 decreases coke formation: higher reusability of the catalysts

  12. Aldol condensation of furfural with acetone over ion-exchanged and impregnated potassium BEA zeolites

    Czech Academy of Sciences Publication Activity Database

    Kikhtyanin, O.; Bulánek, R.; Frolich, K.; Čejka, Jiří; Kubička, D.

    2016-01-01

    Roč. 424, DEC 2016 (2016), s. 358-368 ISSN 1381-1169 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : activated hydrotalcites * carbon-monoxide * cyclic-ketones * Acetone * Furfural * Condensation * Potassium-BEA * Zeolite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.211, year: 2016

  13. Hydroxyapatite catalyzed aldol condensation: Synthesis, spectral linearity, antimicrobial and insect antifeedant activities of some 2,5-dimethyl-3-furyl chalcones

    Science.gov (United States)

    Subramanian, M.; Vanangamudi, G.; Thirunarayanan, G.

    2013-06-01

    A series of 2,5-dimethyl-3-furyl chalcones [2E-1-(2,5-dimethyl-3-furyl)-3-(substituted phenyl)-2-propen-1-ones] have been synthesized by Hydrotalcite catalyzed aldol condensation between 3-acetyl-2,5-dimethylfuron and substituted benzaldehydes. Yields of chalcones are more than 80%. These chalcones were characterized by their physical constants and spectral data. The group frequencies of infrared ν(cm-1) of CO s-cis and s-trans, CH in-plane and out of plane, CHdbnd CH out of plane, lbond2 Cdbnd Crbond2 out of plane modes, NMR chemical shifts δ(ppm) of Hα, Hβ, CO, Cα and Cβ of these chalcones were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analyses. From the results of statistical analyses, the effects of substituents on the group frequencies are explained. Antibacterial, antifungal and insect antifeedant activities of these chalcones have been studied.

  14. Modified calcium oxide as stable solid base catalyst for Aldol ...

    Indian Academy of Sciences (India)

    A highly efficient and stable solid-base catalyst for Aldol condensation was prepared by modifying commercial CaO with benzyl bromide in a simple way. It was found that modified CaO can effectively catalyse the Aldol condensation of cyclohexanone and benzaldehyde, as well as various benzaldehydes, to produce ...

  15. Influence of the Organocatalyst in the Aldol/Mannich-Type Product Selectivities in C−C Bond Forming Reactions

    NARCIS (Netherlands)

    Dominguez de Maria, Pablo; Bracco, Paula; Castelhano, Luiz Fernando; Bargeman, Gerrald

    2011-01-01

    Several organocatalysts were tested in the cross condensation of isobutyraldehyde and acetone. Formation of aldol-type and Mannich-type (“aldol condensation”) products was assessed, and Aldol/Mannich proportion studied under several reaction conditions and at different conversions. Organocatalysts

  16. Condensers

    International Nuclear Information System (INIS)

    Andrieux, M.B.

    1984-01-01

    Characteristics of the condenser cooling waters of various French 900 MW nuclear power plants. Design and description of various types of condensers: condensers feeded directly with river water, condensers feeded by cooling towers, condensers feeded with sea water of brackish water. Presentation of the main problems encountered with the brass bundles (ammoniacal corrosion, erosion of the peripheral tubes, vibrations of the tubes), with the titanium bundles, with the tubular plates, the tubes-tubular plates assemblies, the coatings of the condenser water chamber (sea water), the vapor by-pass and with the air inlet. Analysis of the in service performances such as condensation pressure, oxygen content and availability [fr

  17. Metal-catalyzed asymmetric aldol reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Luiz C.; Lucca Junior, Emilio C. de; Ferreira, Marco A. B.; Polo, Ellen C., E-mail: ldias@iqm.unicamp.br [Universidade de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2012-12-15

    The aldol reaction is one of the most powerful and versatile methods for the construction of C-C bonds. Traditionally, this reaction was developed in a stoichiometric version; however, great efforts in the development of chiral catalysts for aldol reactions were performed in recent years. Thus, in this review article, the development of metal-mediated chiral catalysts in Mukaiyama-type aldol reaction, reductive aldol reaction and direct aldol reaction are discussed. Moreover, the application of these catalysts in the total synthesis of complex molecules is discussed. (author)

  18. Mukaiyama Aldol Reactions in Aqueous Media

    OpenAIRE

    Kitanosono, Taku; Kobayashi, Shū

    2013-01-01

    Mukaiyama aldol reactions in aqueous media have been surveyed. While the original Mukaiyama aldol reactions entailed stoichiometric use of Lewis acids in organic solvents under strictly anhydrous conditions, Mukaiyama aldol reactions in aqueous media are not only suitable for green sustainable chemistry but are found to produce singular phenomena. These findings led to the discovery of a series of water-compatible Lewis acids such as lanthanide triflates in 1991. Our understanding on these be...

  19. Inter- and intramolecular aldol reactions promiscuously catalyzed by a proline-based tautomerase

    NARCIS (Netherlands)

    Rahimi, Mehran; Geertsema, Edzard M; Miao, Yufeng; van der Meer, Jan-Ytzen; Bosch, van den Thea; de Haan, Pim; Zandvoort, Ellen; Poelarends, Gerrit J

    2017-01-01

    The enzyme 4-oxalocrotonate tautomerase (4-OT), which in nature catalyzes a tautomerization step as part of a catabolic pathway for aromatic hydrocarbons, was found to promiscuously catalyze different types of aldol reactions. These include the self-condensation of propanal, the cross-coupling of

  20. Inter- and intramolecular aldol reactions promiscuously catalyzed by a proline-based tautomerase.

    Science.gov (United States)

    Rahimi, Mehran; Geertsema, Edzard M; Miao, Yufeng; van der Meer, Jan-Ytzen; van den Bosch, Thea; de Haan, Pim; Zandvoort, Ellen; Poelarends, Gerrit J

    2017-03-28

    The enzyme 4-oxalocrotonate tautomerase (4-OT), which in nature catalyzes a tautomerization step as part of a catabolic pathway for aromatic hydrocarbons, was found to promiscuously catalyze different types of aldol reactions. These include the self-condensation of propanal, the cross-coupling of propanal and benzaldehyde, the cross-coupling of propanal and pyruvate, and the intramolecular cyclizations of hexanedial and heptanedial. Mutation of the catalytic amino-terminal proline (P1A) greatly reduces 4-OT's aldolase activities, whereas mutation of another active site residue (F50A) strongly enhances 4-OT's aldolase activities, indicating that aldolization is an active site process. This catalytic promiscuity of 4-OT could be exploited as starting point to create tailor-made, artificial aldolases for challenging self- and cross-aldolizations.

  1. alpha-Methoxymethyl ketones via aldol reaction

    Czech Academy of Sciences Publication Activity Database

    Kasal, Alexander; Buděšínský, Miloš

    2013-01-01

    Roč. 69, č. 46 (2013), s. 9663-9674 ISSN 0040-4020 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:61388963 Keywords : NMR * steroids * synthesis * aldol reaction Subject RIV: CC - Organic Chemistry Impact factor: 2.817, year: 2013

  2. Acid-Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization.

    Science.gov (United States)

    Lewis, Jennifer D; Van de Vyver, Stijn; Román-Leshkov, Yuriy

    2015-08-17

    Hf-, Sn-, and Zr-Beta zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

    Full Text Available Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination.

  4. Peculiar behavior of MWW materials in aldol condensation of furfural and acetone

    Czech Academy of Sciences Publication Activity Database

    Kikhtyanin, O.; Eliášová, Pavla; Jindrová, T.; Kubička, D.

    2014-01-01

    Roč. 43, č. 27 (2014), s. 10628-10641 ISSN 1477-9226 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : acetone * aldehydes * batch reactors Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.197, year: 2014

  5. Estrutura & História.

    Directory of Open Access Journals (Sweden)

    Alicia Ferreira Gonçalves

    2015-06-01

    Full Text Available O presente artigo discorre sobre as ligações entre estrutura e história a partir das perspectivas estruturalista francesa e culturalista norte-americana, focalizando as interlocuções teóricas entre Claude Lévi-Strauss e Marshall Sahlins entre o final dos anos 1940 e ao longo dos anos 1990 do século XX.

  6. Water Condensation

    DEFF Research Database (Denmark)

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund

    2014-01-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...

  7. Unexpected Retroaldol-Aldol Reaction during O-Alkylation of Hydroxylated Vince Lactam Derivatives.

    Science.gov (United States)

    Bengtsson, Christoffer; Wetzel, Alexander; Bergman, Joakim; Brånalt, Jonas

    2016-01-15

    The unexpected retroaldol-aldol reaction during O-alkylation of a β-hydroxy lactam was found to be highly dependent on the temperature and shows a remarkable solvent effect. In DMF, O-alkylation is faster than retroaldol-aldol rearrangement giving exclusively products with retention of configuration. In THF, O-alkylation is slower than rearrangement, giving selectively products with inversion of stereochemistry. In DMSO, a retroaldol reaction followed by fast intramolecular proton transfer occurs to give the ring-opened aldehyde.

  8. Steam condenser

    International Nuclear Information System (INIS)

    Masuda, Fujio

    1980-01-01

    Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)

  9. Catalytic asymmetric synthesis of acyclic arrays by tandem 1,4-addition-aldol reactions

    NARCIS (Netherlands)

    Howell, Gareth P.; Fletcher, Stephen P.; Geurts, Koen; ter Horst, Bjorn; Feringa, Ben L.

    2006-01-01

    Herein, we report efficient acyclic stereocontrol in tandem 1,4-addition-aldol reactions triggered by catalytic asymmetric organometallic addition. Grignard reagents add to alpha,beta-unsaturated thioesters in a 1,4-fashion and the resulting magnesium enolatesare trapped with aromatic or aliphatic

  10. Asymmetric Aldol Additions: A Guided-Inquiry Laboratory Activity on Catalysis

    Science.gov (United States)

    King, Jorge H. Torres; Wang, Hong; Yezierski, Ellen J.

    2018-01-01

    Despite the importance of asymmetric catalysis in both the pharmaceutical and commodity chemicals industries, asymmetric catalysis is under-represented in undergraduate chemistry laboratory curricula. A novel guided-inquiry experiment based on the asymmetric aldol addition was developed. Students conduct lab work to compare the effectiveness of…

  11. Highly diastereoselective preparation of aldol products using new functionalized allylic aluminum reagents.

    Science.gov (United States)

    Shen, Zhi-Liang; Peng, Zhihua; Yang, Chun-Ming; Helberg, Julian; Mayer, Peter; Marek, Ilan; Knochel, Paul

    2014-02-07

    Chloro-substituted triethylsilyl enol ethers derived from cyclohexanone and related ketones are converted with aluminum powder in the presence of indium trichloride to functionalized allylic aluminum reagents which represent a new type of synthetic equivalent of metal enolates. These allylic organometallics undergo highly diastereoselective additions to aldehydes and methyl aryl ketones, giving aldol products with a β-quaternary center.

  12. Catalyst-free aldol reaction of N-substituted rhodanines on aqueous ...

    Indian Academy of Sciences (India)

    N S DEVI

    2018-02-07

    Feb 7, 2018 ... Abstract. Rhodanine derivatives are highly valuable heterocycles in drug discovery. Here, we developed aldol reaction of N-substituted rhodanines and aromatic aldehydes on water. The reaction was performed at room temperature affording the products in good to high yield. This synthetic protocol uses ...

  13. Aggregation and Cooperative Effects in the Aldol Reactions of Lithium Enolates

    NARCIS (Netherlands)

    Larrañaga, O.; de Cózar, A.; Bickelhaupt, F.M.; Zangi, R.; Cossío, F.P.

    2013-01-01

    Density functional theory and Car-Parrinello molecular dynamics simulations have been carried out for model aldol reactions involving aggregates of lithium enolates derived from acetaldehyde and acetone. Formaldehyde and acetone have been used as electrophiles. It is found that the geometries of the

  14. Catalyst-free aldol reaction of N-substituted rhodanines on aqueous ...

    Indian Academy of Sciences (India)

    hp

    Catalyst-free aldol reaction of N-substituted rhodanines on aqueous media. N S DEVI and NIRADA DEVI*. Department of Chemistry, Cotton University, Guwahati, Assam 781 001, India. *Email: niradadevicu@gmail.com. List of Contents. 1. Data of all compounds. S2 – S5. 2. Spectra of selected compounds. S6 – S25 ...

  15. Heterogeneously Catalysed Aldol Reactions in Supercritical Carbon Dioxide as Innovative and Non-Flammable Reaction Medium

    DEFF Research Database (Denmark)

    Musko, Nikolai; Grunwaldt, Jan-Dierk

    2011-01-01

    hydrogenation of 2-butenal and is therefore a potential catalyst for the “one-pot” synthesis of 2-ethyl-2-hexenal and 2-ethylhexanal via combined hydrogenation and aldol reaction from 2-butenal. A number of characterisation techniques, such as temperature-programmed desorption of ammonia (NH3-TPD), transmission...

  16. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.

    Science.gov (United States)

    In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

  17. ALDOL- AND MANNICH-TYPE REACTIONS VIA IN SITU OLEFIN MIGRATION IN IONIC LIQUID

    Science.gov (United States)

    An aldol-type and a Mannich-type reaction via the cross-coupling of aldehydes and imines with allylic alcohols catalyzed by RuCl2(PPh3)3 was developed with ionic liquid as the solvent. The solvent/catalyst system could be reused for at least five times with no loss of reactiv...

  18. As estruturas territoriais dos insetos

    Directory of Open Access Journals (Sweden)

    Witold Zmitrowicz

    2001-04-01

    Full Text Available AS SOCIEDADES de insetos utilizam muitos tipos de materiais e recursos biológicos para construir seus abrigos. As disposições espaciais e estruturas de apoio são criadas de forma engenhosa, oferecendo condições adequadas para a criação da prole, a produção ou o armazenamento de alimentos. A sua localização e as suas interconexões as inserem nas áreas circundantes, e elas podem aproveitar vantagens circunstanciais oferecidas pelo meio ambiente. As técnicas de construção e de manutenção fazem parte da cultura desses seres, e permitem uma visão interessante de soluções obtidas mediante a utilização eficiente de uma ampla gama de recursos disponíveis.INSECT SOCIETIES use many kinds of materials and biologic resources to build their shelters. Space arrangements and supporting structures are created in an ingenious way to provide adequate conditions for development of the young, for food production or storage. Their location and interconnections insert them into the surrounding areas, and they may take advantage of circumstantial benefits of their environment. Building and maintenance techniques belong to the culture of these beings, and they offer an interesting vision of solutions based on efficient use of a wide range of available resources.

  19. Asymmetric Michael-aldol tandem reaction of 2-substituted benzofuran-3-ones and enones: a facile synthesis of griseofulvin analogues.

    Science.gov (United States)

    Dong, Nan; Li, Xin; Wang, Feng; Cheng, Jin-Pei

    2013-09-20

    A highly enantioselective Michael-aldol tandem reaction with respect to prochiral 2-substituted benzofuran-3-ones and enones by a facile primary amine catalyst was investigated. The approach provides rapid access to the desired pharmaceutically active griseofulvin analogues.

  20. Cooperative Effects Between Arginine and Glutamic Acid in the Amino Acid-Catalyzed Aldol Reaction.

    Science.gov (United States)

    Valero, Guillem; Moyano, Albert

    2016-08-01

    Catalysis of the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde by mixtures of L-Arg and of L-Glu in wet dimethyl sulfoxide (DMSO) takes place with higher enantioselectivity (up to a 7-fold enhancement in the anti-aldol for the 1:1 mixture) than that observed when either L-Glu or L-Arg alone are used as the catalysts. These results can be explained by the formation of a catalytically active hydrogen-bonded complex between both amino acids, and demonstrate the possibility of positive cooperative effects in catalysis by two different α-amino acids. Chirality 28:599-605, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Synthesis of non-racemic α-hydroxyphosphonates via asymmetric phospho-aldol reaction.

    Science.gov (United States)

    Spilling, Christopher D; Malla, Raj K

    2015-01-01

    It has been more than 50 years since the first phospho-aldol reactions of dialkyl phosphites were reported. These efficient P-C bond-forming reactions have become the cornerstone of methods for the synthesis of α-hydroxyphosphonates and, by numerous available substitution reactions, the synthesis of other α- and γ-substituted phosphonates and phosphonic acids. Much of the interest in α- and γ-substituted phosphonates and phosphonic acids has been stimulated by reports of their biological activity, which is often dependent upon their absolute and relative stereochemistry. In this chapter, we review diastereoselective and enantioselective additions of dialkyl phosphites to aldehydes and ketones, otherwise called the phospho-aldol, Pudovik or Abramov reactions.

  2. Cooperative organocatalysis of Mukaiyama-type aldol reactions by thioureas and nitro compounds

    KAUST Repository

    Bukhriakov, Konstantin

    2016-05-16

    A unique organocatalytic system for Mukaiyama-type aldol reactions based on the cooperative action of nitro compounds and thioureas has been identified. This system is compatible with a wide range of substrates and does not require low temperatures, inert atmospheres, or an aqueous workup. A catalytic mechanism based on nitro group-mediated silyl cation transfer has been proposed. © The Royal Society of Chemistry 2016.

  3. Catalytic enantioselective N-nitroso aldol reaction of γ,δ-unsaturated δ-lactones.

    Science.gov (United States)

    Yanagisawa, Akira; Fujinami, Takeo; Oyokawa, Yu; Sugita, Takuya; Yoshida, Kazuhiro

    2012-05-18

    A catalytic asymmetric N-nitroso aldol reaction of γ,δ-didehydro-δ-lactones with nitrosoarenes was achieved using chiral tin dibromide as the chiral precatalyst and sodium ethoxide as the base precatalyst in the presence of ethanol. Optically active α-hydroxyamino ketones with up to 99% ee were regioselectively obtained in moderate to high yields from various δ-aryl-substituted γ,δ-didehydro-δ-valerolactones and o-substituted nitrosoarenes.

  4. Emergency condensator

    International Nuclear Information System (INIS)

    Hamazaki, Ryoichi.

    1992-01-01

    The condensator of the present invention has a condensate return pipe for returning condensates formed by concentration of steams in a bundle of heat transfer tubes. A flow rate control valve is disposed to the return pipe, and the opening degree of the control valve is controlled by a valve opening degree control device which receives a reactor pressure signal under control. The valve opening degree control device outputs a control signal of 0% valve opening degree when reactor pressure is lower than the lowermost control value and outputs control signal of 100% value opening degree if it is greater than the uppermost control value. On the other hand, when it is between the lowermost value and the uppermost value, it outputs a control signal for demanding an opening degree in proportion to the difference between the reactor pressure and the lowermost control value. Since it is thus controlled, even if steams and condensaes are circulated as they are by natural convection, there is no worry that reactor pressure lowers excessively and no operator's manual handling is necessary. (T.M.)

  5. Remarkable phosphine-effect on the intramolecular aldol reactions of unsaturated 1,5-diketones: highly regioselective synthesis of cross-conjugated dienones.

    Science.gov (United States)

    Thalji, Reema K; Roush, William R

    2005-12-07

    We report a phosphine-mediated intramolecular aldol cyclization of unsaturated diketones that proceeds with extremely high levels of regioselectivity for the cross-conjugated bicyclic dienone products. The sense of regioselectivity observed in this reaction is complementary to that obtained using traditional aldol conditions. Experimental evidence that supports the involvement of a phosphine Michael adduct is described.

  6. Sustentabilidade organizacional: as estruturas e as agencias

    OpenAIRE

    Domingues, Ivo; Silva, Carlos; Araújo, Raquel

    2013-01-01

    Neste texto é problematizada a regulação e a sustentabilidade organizacional a partir de conceitos tradicionalmente reconhecidos na teoria organizacional - estruturas organizacionais e sociais, racionalização, conhecimentos e aprendizagem organizacional, tecnologia e cultura organizacional. A reflexão é orientada para a análise de continuidades e descontinuidades, de alinhamentos e desalinhamentos e dos seus reflexos na regulação e na sustentabilidade organizacionais.

  7. Halogeno Aldol Reaction of Ethyl Vinyl Ketone and Aldehydes Mediated by Titanium Tetrachloride

    Directory of Open Access Journals (Sweden)

    Guigen Li

    2000-12-01

    Full Text Available A three-component halogeno aldol reaction has been developed by using titanium tetrachloride as the halogen source as well as the Lewis acid mediator. The dehydration and elimination of hydrogen chloride were inhibited by conducting the reaction at 0 °C in dichloromethane or at room temperature with a shortened reaction time. Seven examples were examined, giving good to high yields (61 - 92% and modest stereoselectivity (syn/anti: 2.2/1.0 - 8.4/1.0.

  8. Stereocontrolled synthesis of syn-β-Hydroxy-α-amino acids by direct aldolization of pseudoephenamine glycinamide.

    Science.gov (United States)

    Seiple, Ian B; Mercer, Jaron A M; Sussman, Robin J; Zhang, Ziyang; Myers, Andrew G

    2014-04-25

    β-Hydroxy-α-amino acids figure prominently as chiral building blocks in chemical synthesis and serve as precursors to numerous important medicines. Reported herein is a method for the synthesis of β-hydroxy-α-amino acid derivatives by aldolization of pseudoephenamine glycinamide, which can be prepared from pseudoephenamine in a one-flask protocol. Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide in the presence of LiCl followed by addition of an aldehyde or ketone substrate affords aldol addition products that are stereochemically homologous with L- or D-threonine, respectively. These products, which are typically solids, can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction with sodium borohydride. This new chemistry greatly facilitates the construction of novel antibiotics of several different classes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Lewis base activation of Lewis acids: catalytic, enantioselective vinylogous aldol addition reactions.

    Science.gov (United States)

    Denmark, Scott E; Heemstra, John R

    2007-07-20

    The generality of Lewis base catalyzed, Lewis acid mediated, enantioselective vinylogous aldol addition reactions has been investigated. The combination of silicon tetrachloride and chiral phosphoramides is a competent catalyst for highly selective additions of a variety of alpha,beta-unsaturated ketone-, 1,3-diketone-, and alpha,beta-unsaturated amide-derived dienolates to aldehydes. These reactions provided high levels of gamma-site selectivity for a variety of substitution patterns on the dienyl unit. Both ketone- and morpholine amide-derived dienol ethers afforded high enantio- and diastereoselectivity in the addition to conjugated aldehydes. Although alpha,beta-unsaturated ketone-derived dienolate did not react with aliphatic aldehydes, alpha,beta-unsaturated amide-derived dienolates underwent addition at reasonable rates affording high yields of vinylogous aldol product. The enantioselectivities achieved with the morpholine derived-dienolate in the addition to aliphatic aldehydes was the highest afforded to date with the silicon tetrachloride-chiral phosphoramide system. Furthermore, the ability to cleanly convert the morpholine amide to a methyl ketone was demonstrated.

  10. Dropwise condensation originating

    International Nuclear Information System (INIS)

    Croix, J.-M.

    1975-01-01

    Both principal modes of steam condensation (film or dropwise condensation) are surveyed. Available results are exposed as for contact angle measurements, and the heat transfer mechanisms proposed. The efficiency of the dropwise condensation mode is illustrated from the excellent results obtained in the laboratory by J.M. NIEZBORALA, using an organic compound (fluorinated disulfide) for originating the condensation [fr

  11. Asymmetric assembly of aldose carbohydrates from formaldehyde and glycolaldehyde by tandem biocatalytic aldol reactions

    Science.gov (United States)

    Szekrenyi, Anna; Garrabou, Xavier; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Clapés, Pere

    2015-09-01

    The preparation of multifunctional chiral molecules can be greatly simplified by adopting a route via the sequential catalytic assembly of achiral building blocks. The catalytic aldol assembly of prebiotic compounds into stereodefined pentoses and hexoses is an as yet unmet challenge. Such a process would be of remarkable synthetic utility and highly significant with regard to the origin of life. Pursuing an expedient enzymatic approach, here we use engineered D-fructose-6-phosphate aldolase from Escherichia coli to prepare a series of three- to six-carbon aldoses by sequential one-pot additions of glycolaldehyde. Notably, the pertinent selection of the aldolase variant provides control of the sugar size. The stereochemical outcome of the addition was also altered to allow the synthesis of L-glucose and related derivatives. Such engineered biocatalysts may offer new routes for the straightforward synthesis of natural molecules and their analogues that circumvent the intricate enzymatic pathways forged by evolution.

  12. Multicomponent, Enantioselective Michael-Michael-Aldol-β-Lactonizations Delivering Complex β-Lactones.

    Science.gov (United States)

    Van, Khoi N; Romo, Daniel

    2018-01-19

    Optically active, tertiary amine Lewis bases react with unsaturated acid chlorides to deliver chiral, α,β-unsaturated acylammonium salts. These intermediates participate in a catalytic, enantioselective, three-component process delivering bi- and tricyclic β-lactones through a Michael-Michael-aldol-β-lactonization. In a single operation, the described multicomponent, organocascade process forms complex bi- and tricyclic β-lactones by generating four new bonds, two rings, and up to four contiguous stereocenters. In the racemic series, yields of 22-75% were achieved using 4-pyrrolidinopyridine as Lewis base. In the enantioselective series employing isothiourea catalysts, a kinetic resolution of the initially formed racemic Michael adduct appears operative, providing yields of 46% to quantitative (based on 50% max) with up to 94:6 er. Some evidence for a dynamic kinetic asymmetric transformation for tricyclic-β-lactone 1d was obtained following optimization (yields up to 61%, 94:6 er) through a presumed reversible Michael.

  13. Quests em World Of Warcraft como estrutura narrativa seriada

    Directory of Open Access Journals (Sweden)

    Jônatas Kerr de Oliveira

    2010-10-01

    Full Text Available Assumindo que as quests em World of Warcraft funcionam como uma estrutura narrativa dentro do jogo, busca-se verificar se esta estrutura apresenta características que possam caracterizá-la como uma narrativa seriada. Para tal, é feita uma análise das principais características da narrativa seriada televisiva, assim como da estrutura de quests, para verificar a viabilidade de tal aproximação. Sendo a estrutura narrativa de quests em MMORPGs uma estrutura narrativa seriada, abre-se um grande leque de possibilidades, tanto para as análises teóricas dos videogames, utilizando o ferramental adaptado, como para os game designers utilizarem este referencial para acrescer detalhes aos mundos ficcionais criados.

  14. Condensate treatment system

    International Nuclear Information System (INIS)

    Masumitsu, Isao; Ito, Tomoaki; Kajio, Shozo; Takayama, Toshio; Ishikawa, Yasuyuki

    1992-01-01

    Condensate treatment system is installed for purifying condensate in thermal and nuclear power stations. Once-through boilers appeared, and in order to maintain the high purity water quality of condensate, condensate desalting facilities were installed in 1962 in Japan. There are the single type using condensate desalting facility only and the combined type of condensate prefilter and condensate desalting facility. The purpose of installing condensate treatment system is to remove corrosion products and ion components generated from the structural materials of plants and to remove sea water composition if it leaks. The general steam-condensate system in thermal power plants is explained. A standard JIS B 8223 'Quality of feedwater and boiler water for boilers' is instituted. The water treatment for boilers is carried out by the treatment of makeup feed, chemical treatment in boilers and blow. In the case of once-through boilers, blow cannot be done, accordingly, very high purity water is required. Condensate prefilter, condensate desalting facility, the watching of condensate treatment system and the operation in combined water treatment are reported. Also the condensate prefilters and the condensate desalting facilities for BWR and PWR plants are described. (K.I.)

  15. N-Heterocyclic Carbene-Catalyzed Vinylogous Mukaiyama Aldol Reaction of α-Keto Esters and α-Trifluoromethyl Ketones

    KAUST Repository

    Du, Guang-Fen

    2015-11-05

    © Georg Thieme Verlag Stuttgart · New York · Synthesis 2016. N-Heterocyclic carbene (NHC)-catalyzed vinylogous Mukaiyama aldol reaction of ketones was developed. Under the catalysis of 5 mol% NHC, α-keto esters and α-trifluoromethyl ketones reacted with 2-(trimethysilyloxy)furan efficiently to produce γ-substituted butenolides containing adjacent quaternary and tertiary carbon centers in high yields with good diastereoselectivities.

  16. Accurate Reaction Enthalpies and Sources of Error in DFT Thermochemistry for Aldol, Mannich, and α-Aminoxylation Reactions

    Science.gov (United States)

    Wheeler, Steven E.; Moran, Antonio; Pieniazek, Susan N.; Houk, K. N.

    2009-08-01

    Enthalpies for bond-forming reactions that are subject to organocatalysis have been predicted using the high-accuracy CBS-QB3 model chemistry and six DFT functionals. Reaction enthalpies were decomposed into contributions from changes in bonding and other intramolecular effects via the hierarchy of homodesmotic reactions. The order of the reaction exothermicities (aldol Mannich ≈ α-aminoxylation) arises primarily from changes in formal bond types mediated by contributions from secondary intramolecular interactions. In each of these reaction types, methyl substitution at the β- and γ-positions stabilizes the products relative to the unsubstituted case. The performance of six DFT functionals (B3LYP, B3PW91, B1B95, MPW1PW91, PBE1PBE, and M06-2X), MP2, and SCS-MP2 has been assessed for the prediction of these reaction enthalpies. Even though the PBE1PBE and M06-2X functionals perform well for the aldol and Mannich reactions, errors roughly double when these functionals are applied to the α-aminoxylation reactions. B3PW91 and B1B95, which offer modest accuracy for the aldol and Mannich reactions, yield reliable predictions for the two α-aminoxylation reactions. The excellent performance of the M06-2X and PBE1PBE functionals for aldol and Mannich reactions stems from the cancellation of sizable errors arising from inadequate descriptions of the underlying bond transformations and intramolecular interactions. SCS-MP2/cc-pVTZ performs most consistently across these three classes of reactions, although the reaction exothermicities are systematically underestimated by 1-3 kcal mol-1. Conventional MP2, when paired with the cc-pVTZ basis set, performs somewhat better than SCS-MP2 for some of these reactions, particularly the α-aminoxylations. Finally, the merits of benchmarking DFT functionals for the set of simple chemically meaningful transformations underlying all bond-forming reactions are discussed.

  17. Accurate reaction enthalpies and sources of error in DFT thermochemistry for aldol, Mannich, and alpha-aminoxylation reactions.

    Science.gov (United States)

    Wheeler, Steven E; Moran, Antonio; Pieniazek, Susan N; Houk, K N

    2009-09-24

    Enthalpies for bond-forming reactions that are subject to organocatalysis have been predicted using the high-accuracy CBS-QB3 model chemistry and six DFT functionals. Reaction enthalpies were decomposed into contributions from changes in bonding and other intramolecular effects via the hierarchy of homodesmotic reactions. The order of the reaction exothermicities (aldol Mannich approximately alpha-aminoxylation) arises primarily from changes in formal bond types mediated by contributions from secondary intramolecular interactions. In each of these reaction types, methyl substitution at the beta- and gamma-positions stabilizes the products relative to the unsubstituted case. The performance of six DFT functionals (B3LYP, B3PW91, B1B95, MPW1PW91, PBE1PBE, and M06-2X), MP2, and SCS-MP2 has been assessed for the prediction of these reaction enthalpies. Even though the PBE1PBE and M06-2X functionals perform well for the aldol and Mannich reactions, errors roughly double when these functionals are applied to the alpha-aminoxylation reactions. B3PW91 and B1B95, which offer modest accuracy for the aldol and Mannich reactions, yield reliable predictions for the two alpha-aminoxylation reactions. The excellent performance of the M06-2X and PBE1PBE functionals for aldol and Mannich reactions stems from the cancellation of sizable errors arising from inadequate descriptions of the underlying bond transformations and intramolecular interactions. SCS-MP2/cc-pVTZ performs most consistently across these three classes of reactions, although the reaction exothermicities are systematically underestimated by 1-3 kcal mol(-1). Conventional MP2, when paired with the cc-pVTZ basis set, performs somewhat better than SCS-MP2 for some of these reactions, particularly the alpha-aminoxylations. Finally, the merits of benchmarking DFT functionals for the set of simple chemically meaningful transformations underlying all bond-forming reactions are discussed.

  18. Engineering the donor selectivity of D-fructose-6-phosphate aldolase for biocatalytic asymmetric cross-aldol additions of glycolaldehyde.

    Science.gov (United States)

    Szekrenyi, Anna; Soler, Anna; Garrabou, Xavier; Guérard-Hélaine, Christine; Parella, Teodor; Joglar, Jesús; Lemaire, Marielle; Bujons, Jordi; Clapés, Pere

    2014-09-22

    D-Fructose-6-phosphate aldolase (FSA) is a unique catalyst for asymmetric cross-aldol additions of glycolaldehyde. A combination of a structure-guided approach of saturation mutagenesis, site-directed mutagenesis, and computational modeling was applied to construct a set of FSA variants that improved the catalytic efficiency towards glycolaldehyde dimerization up to 1800-fold. A combination of mutations in positions L107, A129, and A165 provided a toolbox of FSA variants that expand the synthetic possibilities towards the preparation of aldose-like carbohydrate compounds. The new FSA variants were applied as highly efficient catalysts for cross-aldol additions of glycolaldehyde to N-carbobenzyloxyaminoaldehydes to furnish between 80-98 % aldol adduct under optimized reaction conditions. Donor competition experiments showed high selectivity for glycolaldehyde relative to dihydroxyacetone or hydroxyacetone. These results demonstrate the exceptional malleability of the active site in FSA, which can be remodeled to accept a wide spectrum of donor and acceptor substrates with high efficiency and selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Characterization and mechanism insight of accelerated catalytic promiscuity of Sulfolobus tokodaii (ST0779) peptidase for aldol addition reaction.

    Science.gov (United States)

    Li, Rong; Perez, Bianca; Jian, Hui; Jensen, Mads Mørk; Gao, Renjun; Dong, Mingdong; Glasius, Marianne; Guo, Zheng

    2015-11-01

    A novel peptidase from thermophilic archaea Sulfolobus tokodaii (ST0779) is examined for its catalytic promiscuity of aldol addition, which shows comparable activity as porcine pancreatic lipase (PPL, one of the best enzymes identified for biocatalytic aldol addition) at 30 °C but much accelerated activity at elevated temperature. The molecular catalytic efficiency kcat/Km (M(-1) s(-1)) of this thermostable enzyme at 55 °C adds up to 140 times higher than that of PPL at its optimum temperature 37 °C. The fluorescence quenching analysis depicts that the binding constants of PPL are significantly higher than those of ST0779, and their numbers of binding sites show opposite temperature dependency. Thermodynamic parameters estimated by fluorescence quenching analysis unveil distinctly different substrate-binding modes between PPL and ST0779: the governing binding interaction between PPL and substrates is hydrophobic force, while the dominating substrate-binding forces for ST0779 are van der Waals and H-bonds interactions. A reasonable mechanism for ST0779-catalyzed aldol reaction is proposed based on kinetic study, spectroscopic analysis, and molecular stereostructure simulation. This work represents a successful example to identify a new enzyme for catalytic promiscuity, which demonstrates a huge potential to discover and exploit novel biocatalyst from thermophile microorganism sources.

  20. Aldol Reactions of Axially Chiral 5-Methyl-2-(o-arylimino-3-(o-aryl-thiazolidine-4-ones

    Directory of Open Access Journals (Sweden)

    Sule Erol Gunal

    2016-06-01

    Full Text Available Axially chiral 5-methyl-2-(o-arylimino-3-(o-aryl-thiazolidine-4-ones have been subjected to aldol reactions with benzaldehyde to produce secondary carbinols which have been found to be separable by HPLC on a chiral stationary phase. Based on the reaction done on a single enantiomer resolved via a chromatographic separation from a racemic mixture of 5-methyl-2-(α-naphthylimino-3-(α-naphthyl-thiazolidine-4-one by HPLC on a chiral stationary phase, the aldol reaction was shown to proceed via an enolate intermediate. The axially chiral enolate of the thiazolidine-4-one was found to shield one face of the heterocyclic ring rendering face selectivity with respect to the enolate. The selectivities observed at C-5 of the ring varied from none to 11.5:1 depending on the size of the ortho substituent. Although the aldol reaction proceeded with a lack of face selectivity with respect to benzaldehyde, recrystallization returned highly diastereomerically enriched products.

  1. Condensation in insulated homes

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, R A

    1978-05-28

    A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)

  2. Os efeitos da estrutura organizacional no processo de aprendizagem organizacional

    OpenAIRE

    Moraes Júnior, Macário

    2001-01-01

    Este trabalho tem como objetivo analisar os efeitos da estrutura organizacional nos processos de aprendizagem organizacional, considerando o contexto ambiental que circunscreve esta relação e os aspectos moderadores de facilitadores e bloqueadores dos processos de aprendizagem organizacional. A unidade de análise é a organização. O estudo descreve a relação dos dois construtos de pesquisa (estrutura organizacional e processos de aprendizagem organizacional), utilizando uma meto...

  3. Modelling of condensation phenomena

    International Nuclear Information System (INIS)

    Jeong, Jae Jun; Chang, Won Pyo

    1996-07-01

    Condensation occurs when vapor is cooled sufficiently below the saturation temperature to induce the nucleation of droplets. Such nucleation may occur homogeneously within the vapor or heterogeneously on entrained particular matter. Heterogeneous nucleation may occur on the walls of the system, where the temperature is below the saturation temperature. There are two forms of heterogeneous condensation, drop-wise and film-wise. Another form of condensation occurs when vapor directly contacts to subcooled liquid. In nuclear power plant systems, all forms of condensation may occur during normal operation or accident conditions. In this work the modelling of condensation is surveyed, including the Nusselts' laminar film condensation theory in 1916, Rohsenow's turbulent film condensation model in 1950s, and Chen's models in 1987. Major attention is paid on the film condensation models among various research results because of its importance in engineering applications. It is found that theory, experiment, and empirical correlations for film condensation are well established, but research for drop-wise and direct-contact condensation are not sufficient yet. Condensation models in the best-estimate system codes such as RELAP5/MOD3 and CATHARE2 are also investigated. 3 tabs., 11 figs., 36 refs. (Author)

  4. Expedient synthesis of C-aryl carbohydrates by consecutive biocatalytic benzoin and aldol reactions.

    Science.gov (United States)

    Hernández, Karel; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Pohl, Martina; Clapés, Pere

    2015-02-16

    The introduction of aromatic residues connected by a C-C bond into the non-reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C-aril-sLex). In this work, an expedient asymmetric "de novo" synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the α-hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary D-fructose-6-phosphate aldolase and L-rhamnulose-1-phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphate-dependent aldolases require. In this way, 6-C-aryl-L-sorbose, 6-C-aryl-L-fructose, 6-C-aryl-L-tagatose, and 5-C-aryl-L-xylose derivatives are prepared by using this methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Teratoma do ovario com estruturas semelhando cristalino

    Directory of Open Access Journals (Sweden)

    C. Magarinos Torres

    1940-01-01

    Full Text Available Em uma mulher, brasileira, de côr parda, com 48 anos de idade, morta com tuberculose do peritoneo, tuberculose peribronquica do lóbo superior do pulmão esquerdo e tuberculose cronica fibrosa do apice de ambos os pulmões, a necropsía revelou a existencia de um teratoma no ovario esquerdo. O ovario, pouco aumentado de volume, é constituído por duas porções de tamanho sensivelmente egual, de consistencia firme, separadas, em sua superficie, por profundo sulco. Ao córte, tem a aparencia de tecido fibroso em cuja espessura existem numerosos pequenos cistos. Ao microscopio, os cistos são revestidos por epitelio descontinuo, despertando grande interesse o seu conteúdo. Este é formado por fibras e células com morfologia semelhante ás do cristalino. Sugerimos a possibilidade de que, no presente teratoma (Teratoma lentifer, de lens, lentis: cristalino, e ferre: produzir haja participado, de modo dominante, o ectodérme, e mesmo uma região circumscrita do ectodérme, a qual corresponderia aquela emque se desenvolve, habitualmente, a placa do cristalino (« Linsenplatte ». A multiplicidade e a presença exclusiva de estruturas figurando saculos cristalinicos (« Linsensäckchen » são argumentos a favor de uma origem de ponto restrito do ectodérme, destinado a desenvolvimento posterior especifico, qual o da formação do cristalino.

  6. Proceedings: Condenser technology conference

    International Nuclear Information System (INIS)

    Tsou, J.L.; Mussalli, Y.G.

    1991-08-01

    Seam surface condenser and associated systems performance strongly affects availability and heat rate in nuclear and fossil power plants. Thirty-six papers presented at a 1990 conference discuss research results, industry experience, and case histories of condenser problems and solutions. This report contains papers on life extension, performance improvement, corrosion and failure analysis, fouling prevention, and recommendation for future R ampersand D. The information represents recent work on condenser problems and solutions to improve the procurement, operation, and maintenance functions of power plant personnel. Several key points follow: A nuclear and a fossil power plant report show that replacing titanium tube bundles improves condenser availability and performance. One paper reports 10 years of experience with enhanced heat transfer tubes in utility condensers. The newly developed enhanced condenser tubes could further improve condensing heat transfer. A new resistance summation method improves the accuracy of condenser performance prediction, especially for stainless steel and titanium tubed condensers. Several papers describe improved condenser fouling monitoring techniques, including a review of zebra mussel issues

  7. Condensate cleaning systems

    International Nuclear Information System (INIS)

    Yamamoto, Michiyoshi; Oosumi, Katsumi; Takashima, Yoshie; Mitani, Shinji.

    1982-01-01

    Purpose: To decrease the frequency for the backwash and regeneration operations due to the increase in the differential pressure resulted from claddings captured in a mixed floor type desalter, and decrease the amount of radioactive liquid wastes of claddings from the condensate systems by removing claddings with electromagnetic filters. Constitution: In an existent plant, a valves is disposed between a condensate pump and a mixed floor type desalter. A pipeway is branched from a condensate pipe between the condensate pipe and the valve, through which condensates are transferred by a pump to an electromagnetic filter such as of a high gradient type electromagntic filter to remove claddings, then returned to a condensate pipe between the valve and the mixed floor type desalter and, thereafter, are removed with ionic components in the mixed floor type desalter and fed to the reactor. (Yoshino, Y.)

  8. Estrutura social e criação de empresas

    Directory of Open Access Journals (Sweden)

    Gláucia Maria Vasconcelos Vale

    2015-12-01

    Full Text Available RESUMO Para a Sociologia Econômica, as estruturas sociais, no formato de redes interpessoais, influenciam as iniciativas individuais e os resultados econômicos daí derivados. Segundo Granovetter, existem três tipos básicos de estruturas: fortemente acopladas; fortemente desacopladas; fracamente acopladas. Este trabalho situa-se no contexto dessas reflexões, e procura-se, por meio de uma pesquisa amostral realizada com 100 empreendedores, localizados no município de Belo Horizonte, Minas Gerais, Brasil: identificar as estruturas sociais de origem desses indivíduos, em consonância com a tipologia genérica de Granovetter; avaliar a presença de associações entre essas estruturas e a trajetória dos empreendimentos, em particular, a motivação para empreender e o acesso ao mercado. Termina-se por elaborar uma tipologia de estruturas/redes sociais específicas para a análise do empreendedor, composta por três categorias: familiar, profissional e difusa.

  9. Tandem Aldol-Michael Reactions in Aqueous Diethylamine Medium: A Greener and Efficient Approach to Bis-Pyrimidine Derivatives

    Directory of Open Access Journals (Sweden)

    Abdullah M. Al-Majid

    2013-12-01

    Full Text Available A simple protocol, involving the green synthesis for the construction of novel bis-pyrimidine derivatives, 3a–i and 4a–e are accomplished by the aqueous diethylamine media promoted tandem Aldol-Michael reaction between two molecules of barbituric acid derivatives 1a,b with various aldehydes. This efficient synthetic protocol using an economic and environmentally friendly reaction media with versatility and shorter reaction time provides bis-pyrimidine derivatives with high yields (88%–99%.

  10. Direct asymmetric vinylogous aldol reaction of allyl ketones with isatins: Divergent synthesis of 3-hydroxy-2-oxindole derivatives

    KAUST Repository

    Zhu, Bo

    2013-05-03

    6 in 1: The highly enantioselective title reaction is mediated by a bifunctional catalyst and leads to E-configured vinylogous aldol products (see scheme). These products are used as common intermediates in the synthesis of six biologically active 3-hydroxy-2-oxindole derivatives (e.g., CPC-1). Computational studies indicated that the observed stereoselectivity is a result of favorable secondary π-π* and H-bonding interactions in the transition state. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Systematic text condensation

    DEFF Research Database (Denmark)

    Malterud, Kirsti

    2012-01-01

    To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies.......To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies....

  12. Chromosome condensation and segmentation

    International Nuclear Information System (INIS)

    Viegas-Pequignot, E.M.

    1981-01-01

    Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr

  13. Condensation in complex geometries

    International Nuclear Information System (INIS)

    Lauro, F.

    1975-01-01

    A mathematical evaluation of the condensation exchange coefficient can only succeds for well specified cases: small upright or inclined plates, horizontal tubes, small height vertical tubes. Among the main hypotheses accounted for this mathematical development in the case of the condensate, a laminar flow and uniform surface temperature are always considered. In practice certain shapes of surfaces significantly increase the heat transfer during the vapor condensation on a surface wet by the condensate. Such surfaces are rough surfaces such as the condensate is submitted to surface tension effects, negligeable for plane or large curvature surfaces, and the nature of the material may play an important role (temperature gradients). Results from tests on tubes with special shapes, performed in France or out of France, are given [fr

  14. Quartet condensation of fermions.

    Science.gov (United States)

    Talukdar, Aseem; Ma, Michael; Zhang, Fu-Chun

    2007-10-01

    We investigate quartet condensation in fermion systems with four internal states. This is the generalization of the well known BCS superconductor formed by Cooper pair (CP) condensation. Physical examples include spin-3/2 fermionic atoms, bi-layered systems with electrons and holes, quadra-layer spin polarized electron hole system, and two band electronic system. We derive the Landau Ginzberg (LG) free energy for such system in terms of the CP amplitudes. The LG free energy is found to contain attractive interactions among different types of CP's. This will allow them to form bound states of CP's called Cooper quartets (CQ). Using a variational calculation based on the Bogoliubov inequality, we find that CQ condensation may be favored over pair condensation at low temperature. We also study the pairing structures in such systems when pair condensation is preferred.

  15. Environmentally friendly paint and varnish additives based on isobutyrate aldehyde condensation products

    Science.gov (United States)

    Guziałowska-Tic, Joanna; Jan Tic, Wilhelm

    2017-10-01

    The demand for exploitation of new plasticizers and coalescents to be used for production of water dispersion adhesives based on poli(vinyl acetate), turned to be recently of particular significance because the use of all kind of toxic phthalates was banned and certain restrictions were made to use glycol derivatives classified as volatile organic compounds. An alternative for toxic plasticizers used for production of adhesives is hydroxyester (HE-1) obtained from isobutanal during the process of aldol condensation under subsequent Cannizaro and Tischenko reactions. The paper presents selected results of ecotoxicological tests on the environmental impact of hydroxyester HE-1. It was found that the substance is biodegradable and has no negative impact on algae growth rate, however it may inhibit algae biomass growth. The results of Daphnia immobilization test shows that the substance is safe for the aquatic environment. Whereas, at higher concentrations, hydroxyester HE-1 may exhibit acute toxicity to rainbow trout.

  16. Physics of condensed matter

    CERN Document Server

    Misra, Prasanta K

    2012-01-01

    Physics of Condensed Matter is designed for a two-semester graduate course on condensed matter physics for students in physics and materials science. While the book offers fundamental ideas and topic areas of condensed matter physics, it also includes many recent topics of interest on which graduate students may choose to do further research. The text can also be used as a one-semester course for advanced undergraduate majors in physics, materials science, solid state chemistry, and electrical engineering, because it offers a breadth of topics applicable to these majors. The book be

  17. Unexpected Synthesis of 5,6-Dihydropyridin-2(1H)-ones by a Domino Ugi/Aldol/Hydrolysis Reaction Starting from Baylis-Hillman Phosphonium Salts.

    Science.gov (United States)

    Zeng, Xiao-Hua; Wang, Hong-Mei; Ding, Ming-Wu

    2015-05-01

    A one-pot synthetic approach to 5,6-dihydropyridin-2(1H)-ones has been developed using a domino process involving Ugi, aldol, and hydrolysis reactions, starting with Baylis-Hillman phosphonium salts, primary amines, isocyanides, and arylglyoxals.

  18. Catalyst-free synthesis of α1-oxindole-α-hydroxyphosphonates via phospha-aldol reaction of isatins employing N-heterocyclic phosphine (NHP)-thiourea.

    Science.gov (United States)

    Molleti, Nagaraju; Yong Kang, Jun

    2016-09-26

    A highly efficient phospha-aldol reaction for the synthesis of α 1 -oxindole-α-hydroxyphosphonates is developed utilizing N-heterocyclic phosphine (NHP)-thiourea as a phosphonylation reagent under catalyst, additive free conditions. This methodology encompasses a variety of isatin derivatives to provide α 1 -oxindole- α-hydroxyphosphonates up to 99% yield.

  19. In situ generation of less accessible Boc-imines from aldehydes: construction of a quaternary carbon by the Mannich reaction or unprecedented aldol reaction.

    Science.gov (United States)

    Kano, Taichi; Homma, Chihiro; Maruoka, Keiji

    2017-05-31

    In situ generation of less accessible N-Boc-protected imines from aldehydes and their application to the direct three-component Mannich reaction with β-dicarbonyls were realized. The catalyst-free aldol reaction of ynals with β-dicarbonyls was also developed.

  20. Condensation in Microchannels

    National Research Council Canada - National Science Library

    Ameel, Timothy

    1999-01-01

    .... Evaporators and condensers for meso-scale energy systems will most likely be constructed of microchannels due to the microfabrication constraints that limit most structures to two-dimensional planar geometries...

  1. Condensate feeding system

    International Nuclear Information System (INIS)

    Iwami, Hiroshi.

    1981-01-01

    Purpose: To control the dissolved oxygen concentration in water of a condensate feeding system to a desired level. Constitution: Coolant is fed to a nuclear reactor through a route from the steam exit of the reactor and by way of turbine, turbine condensator, condensate pump, condensate desalinator, feedwater heater and feed pump. Steam extraction lines are branched from the turbines, and pipeways are further branched from the steam extraction lines for feeding steam by way of extraction steam injection valves to steam-water mixers disposed on the upstream of the feedwater heater. On the downstream of the feedwater heater, is provided a dissolved oxygen concentration meter, the indication value of which controls the opening degree of the steam injection valves which, in turn, controls the opening degree of the steam feed valves for the feedwater heater to adjust the amount for the injection steams. Accordingly, the dissolved oxygen concentration in the water of the condensate feeding system can be controlled by the inclusion of steams with high dissolved oxygen concentration into the feedwater system from the turbine steam extraction lines by way of the mixers. (Furukawa, Y.)

  2. Observation of the intermediates of in-source aldolization reaction in electrospray ionization mass spectrometry analysis of heteroaromatic aldehydes.

    Science.gov (United States)

    Jiang, Kezhi; Zhang, Xiaoping; Bai, Xingfeng; Lv, Huiqing; Li, Zuguang; Lee, Maw-Rong

    2015-01-01

    Electrospray ionization mass spectrometry (ESI-MS) analyses of 2-(1,2,4-triazole-1-yl)-6-methyl-3- quinolinecarboxaldehyde were carried out by using an ion trap mass spectrometer in a positive-ion mode. Interestingly, several unusual [M + 15](+), [M + 33](+), and [M + 47](+) ions were observed with a high abundance in the ESI-MS spectrum when methanol was used as the ESI solvent. However, only the protonated molecule was obtained with acetonitrile as the ESI solvent. These unusual ions have been proposed as the intermediates of an aldolization reaction occurring in the ESI source, which have been validated by a tandem mass spectrometry experiment, high-performance liquid chromatography/mass spectrometry analysis, and theoretical calculations. A full understanding of this reaction can contribute to the avoidance of analysis errors in the ESI-MS analysis of unknown heteroaromatic aldehydes.

  3. Condensed matter physics

    CERN Document Server

    Isihara, A

    2007-01-01

    More than a graduate text and advanced research guide on condensed matter physics, this volume is useful to plasma physicists and polymer chemists, and their students. It emphasizes applications of statistical mechanics to a variety of systems in condensed matter physics rather than theoretical derivations of the principles of statistical mechanics and techniques. Isihara addresses a dozen different subjects in separate chapters, each designed to be directly accessible and used independently of previous chapters. Topics include simple liquids, electron systems and correlations, two-dimensional

  4. Illustrating the Utility of X-Ray Crystallography for Structure Elucidation through a Tandem Aldol Condensation/Diels-Alder Reaction Sequence

    Science.gov (United States)

    Hoang, Giang T.; Kubo, Tomohiro; Young, Victor G., Jr.; Kautzky, Jacob A.; Wissinger, Jane E.

    2015-01-01

    Two introductory organic chemistry laboratory experiments are described based on the Diels-Alder reaction of 2,3,4,5-tetraphenylcyclopentadienone, which is synthesized prior to or in a one-pot reaction, with styrene. Students are presented with three possible products, the "endo" and "exo" diastereomers and the decarbonylated…

  5. Application of a new tandem isomerization-aldolization reaction of allylic alcohols to the synthesis of three diastereoisomers of (2R)-1,2-O-isopropylidene-4-methylpentane-1,2,3,5-tetraol.

    Science.gov (United States)

    Cuperly, David; Crévisy, Christophe; Grée, René

    2003-08-08

    The tandem isomerization-aldolization reaction of (2R)-1,2-O-isopropylidene-4-penten-1,2,3-triol 3 and formaldehyde gives a mixture of two aldol products 2a and 2b. The stereoselective reduction of each compound by l-Selectride affords two diastereoisomers of (2R)-1,2-O-Isopropylidene-4-methylpentane-1,2,3,5-tetraol while a third diastereoisomer is obtained by stereoselective reduction with Me(4)NHB(OAc)(3).

  6. Condensed matter physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The condensed matter physics research in the Physics Department of Risoe National Laboratory is predominantly experimental utilising diffraction of neutrons and x-rays. The research topics range from studies of structure, excitations and phase transitions in model systems to studies of ion transport, texture and recrystallization kinetics with a more applied nature. (author)

  7. Modular invariant gaugino condensation

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, M.K.

    1991-05-09

    The construction of effective supergravity lagrangians for gaugino condensation is reviewed and recent results are presented that are consistent with modular invariance and yield a positive definite potential of the noscale type. Possible implications for phenomenology are briefly discussed. 29 refs.

  8. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    have quoted, London noted that at the density of liquid helium, the temperature for Bose-Einstein condensation of an ideal gas would be about three degrees above absolute zero.4 Liquid helium shows new properties below 2.1 degrees Kelvin [3]. London boldly suggested that these new properties were a consequence of ...

  9. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 12. Bose-Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. Volume 10 Issue 12 December 2005 pp 142-147. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 4. Bose–Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. General Article Volume 5 Issue 4 April 2000 pp 46-51. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. Bose-Einstein condensation

    Indian Academy of Sciences (India)

    Bose-Einstein Condensation. Vasant Natarajan is at the. Department of Physics,. Indian Institute of. Science. His current research involves trapping of atoms to carry out high precision tests of fundamental physics. He has earlier worked on high precision mass spectrom- etry and on the focussing of atomic beams by laser.

  12. Confinement contains condensates

    DEFF Research Database (Denmark)

    Brodsky, S. J.; Roberts, C. D.; Shrock, R.

    2012-01-01

    Dynamical chiral symmetry breaking and its connection to the generation of hadron masses has historically been viewed as a vacuum phenomenon. We argue that confinement makes such a position untenable. If quark-hadron duality is a reality in QCD, then condensates, those quantities that have common...... evidence and incidentally expose misconceptions in a recent Comment....

  13. Condensed matter physics

    International Nuclear Information System (INIS)

    1990-01-01

    This is a summary of condensed matter physics in Brazil. It discusses as well, the perspectives and financing evolved in this research area for the next decade. It is specially concerned with semiconductors, magnetic materials, superconductivity, polymers, glasses, crystals ceramics, statistical physics, magnetic resonance and Moessbauer spectroscopy. (A.C.A.S.)

  14. Electrons in Condensed Matter

    Indian Academy of Sciences (India)

    Electrons in Condensed Matter. T V Ramakrishnan. Introduction. A hundred years ago, J J Thomson tore light negatively charged particles out of many different kinds of atoms by subjecting them to strong electric fields in discharge tubes. He showed that the same particle (with identical charge e and charge to mass ratio ...

  15. Simple Simulations of DNA Condensation

    Energy Technology Data Exchange (ETDEWEB)

    STEVENS,MARK J.

    2000-07-12

    Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.

  16. An Expeditious and Safe Synthesis of Some Exocyclic α,β-Unsaturated Ketones by Microwave-Assisted Condensation of Cyclic Ketones with Aromatic Aldehydes over Anhydrous Potassium Carbonate

    Directory of Open Access Journals (Sweden)

    Rina Mondal

    2012-01-01

    Full Text Available A rapid, efficient, and solvent-free methodology for synthesis of exocyclic α,β-unsaturated ketones of the categories E-3-arylidene-4-chromanones, E-2-arylidene-1-tetralones, E-2-arylidene-1-indanones, E-3-cinnamylidene-4-chromanones, E-2-cinnamylidene-1-tetralones, E-2-cinnamylidene-1-indanones, α,α′-(E,E-bis(arylidene-cycloalkanones, and α,α′-(E,E-bis(cinnamylidene-cycloalkanones has been developed through cross-aldol condensation of the constituent cyclic ketones and aldehydes by microwave irradiation over anhydrous potassium carbonate. However, for condensation of 1-thio-4-chromanones with aromatic aldehydes by this method, the initially formed exocyclic α,β-unsaturated ketone has been found to undergo isomerization yielding 3-(arylmethylthiochromones.

  17. Catalytic Aldol-Cyclization Cascade of 3-Isothiocyanato Oxindoles with α-Ketophosphonates for the Enantioselective Synthesis of β-Amino-α-hydroxyphosphonates.

    Science.gov (United States)

    Kayal, Satavisha; Mukherjee, Santanu

    2015-11-06

    A cascade aldol-cyclization reaction between 3-isothiocyanato oxindoles and α-ketophosphonates has been developed for the synthesis of β-amino-α-hydroxyphosphonate derivatives. Catalyzed by a quinine-based tertiary amino-thiourea derivative, this reaction delivers 2-thioxooxazolidinyl phosphonates based on a spirooxindole scaffold bearing two contiguous quaternary stereogenic centers in high yields with excellent diastereo- (up to >20:1 dr) and enantioselectivities (up to >99:1 er).

  18. Enantioselective organocatalyzed Oxa-Michael-Aldol cascade reactions: Construction of chiral 4H-chromenes with a trifluoromethylated tetrasubstituted carbon stereocenter

    KAUST Repository

    Zhang, Jing

    2015-03-13

    The first organocatalytic asymmetric synthesis of 4H-chromenes bearing a trifluoromethylated tetrasubstituted carbon center is presented. Chiral secondary amines promote the oxa-Michael-aldol cascade reaction between alkynals and 2-trifluoroacetylphenols via iminium-allenamine activation to produce pharmaceutically important heterocycles with excellent enantioselectivities. The proposed reaction can be scaled-up easily with maintenance of the excellent enantioselectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Catalytic asymmetric access to alpha,beta unsaturated delta-lactones through a vinylogous aldol reaction: application to the total synthesis of the Prelog-Djerassi lactone.

    Science.gov (United States)

    Bluet, G; Bazán-Tejeda, B; Campagne, J M

    2001-11-15

    [reaction--see text] A one-step catalytic asymmetric access to alpha,beta unsaturated delta-lactones is described, using a vinylogous Mukaiyama-aldol reaction between a gamma-substituted dienolate and various aldehydes in the presence of Carreira catalyst CuF.(S)-tolBinap. This methodology has been further applied to a straightforward access to the Prelog-Djerassi lactone.

  20. Organocatalytic decarboxylative aldol reaction of β-ketoacids with α-ketophosphonates en route to the enantioselective synthesis of tertiary α-hydroxyphosphonates.

    Science.gov (United States)

    Vamisetti, Ganga B; Chowdhury, Raghunath; Ghosh, Sunil K

    2017-05-10

    The first example of an asymmetric organocatalyzed decarboxylative aldol reaction of β-ketoacids (aroylacetic acids) with α-ketophosphonates that produces a quaternary chiral centre has been developed. A quinidine based bifunctional urea derivative was identified as the preferred catalyst affording γ-aroyl tertiary α-hydroxyphosphonates in good yield and enantioselectivity. The 31 P NMR spectroscopic study was performed to shed light on the reaction mechanism.

  1. Influence of non condensable gases on condenser performance. Bibliographical study

    International Nuclear Information System (INIS)

    Phong, Vinh

    1970-09-01

    The author proposes a synthesis of a bibliographical study on condenser performance, and more particularly on the influence of non-condensables on these performance. He distinguishes experimental studies, and analytical or theoretical studies. As far as experimental studies are concerned, he discusses various factors: influence of the rate of non condensables and of scan rate, influence of condenser geometry, influence of the exchanged heat flow, influence of the operational pressure, empirical correlations. As far as analytical studies on the influence of non-condensables are concerned, the author discusses and comments diffusion laws, and some specific studies [fr

  2. Research Status of Evaporative Condenser

    Science.gov (United States)

    Wang, Feifei; Yang, Yongan

    2018-02-01

    Reducing energy consumption, saving water resources, recycling cool water are main directions of China’s development. Evaporative condenser using latent heat reduces water resources waste, with energy-saving advantages. This paper reviews the research status of evaporative condenser at home and abroad, and introduces the principle, classification, various influencing factors of evaporative condenser, and puts forward the future research direction.

  3. Recovery of condensate water quality in power generator's surface condenser

    Science.gov (United States)

    Kurniawan, Lilik Adib

    2017-03-01

    In PT Badak NGL Plant, steam turbines are used to drive major power generators, compressors, and pumps. Steam exiting the turbines is condensed in surface condensers to be returned to boilers. Therefore, surface condenser performance and quality of condensate water are very important. One of the recent problem was caused by the leak of a surface condenser of Steam Turbine Power Generator. Thesteam turbine was overhauled, leaving the surface condenser idle and exposed to air for more than 1.5 years. Sea water ingress due to tube leaks worsens the corrosionof the condenser shell. The combination of mineral scale and corrosion product resulting high conductivity condensate at outlet condenser when we restarted up, beyond the acceptable limit. After assessing several options, chemical cleaning was the best way to overcome the problem according to condenser configuration. An 8 hour circulation of 5%wt citric acid had succeed reducing water conductivity from 50 μmhos/cm to below 5 μmhos/cm. The condensate water, then meets the required quality, i.e. pH 8.3 - 9.0; conductivity ≤ 5 μmhos/cm, therefore the power generator can be operated normally without any concern until now.

  4. Condensed matter physics

    CERN Document Server

    Marder, Michael P

    2010-01-01

    This Second Edition presents an updated review of the whole field of condensed matter physics. It consolidates new and classic topics from disparate sources, teaching not only about the effective masses of electrons in semiconductor crystals and band theory, but also about quasicrystals, dynamics of phase separation, why rubber is more floppy than steel, granular materials, quantum dots, Berry phases, the quantum Hall effect, and Luttinger liquids.

  5. Loteamentos, expansão e estrutura urbana

    Directory of Open Access Journals (Sweden)

    Décio Rigatti

    2002-06-01

    Full Text Available O rápido processo de urbanização que as cidades brasileiras apresentam, principalmente, a partir do final da década de 40, gera um crescimento acelerado da população urbana e produz nas cidades uma enorme demanda por terra urbanizada. O presente trabalho tem como objetivos centrais: analisar o parcelamento do solo urbano como modalidade de expansão de áreas urbanas; avaliar de que modo a incorporação de novas áreas, como urbanas, insere-se no tecido preexistente; examinar como os diversos parcelamentos do solo urbano estruturam o conjunto do tecido urbano, gerando diferentes níveis de acessibilidade geral; indicar medidas que o poder público municipal pode inserir como formas de controle e superação dos problemas apresentados presentemente. Como estudo de caso, discutiremos a formação e estruturação da cidade de Alvorada, localizada no limite leste de Porto Alegre, cidade que se originou da implantação de sucessivos loteamentos, ao invés da expansão de um núcleo urbano preexistente. O trabalho consiste, essencialmente, na reconstituição do processo de formação da estrutura urbana de Alvorada, a partir da inclusão sistemática de parcelamentos do solo ao longo do tempo e na avaliação da estrutura urbana resultante e suas relações com os potenciais de práticas sociais no espaço.

  6. Panorama da estrutura presidiária brasileira

    Directory of Open Access Journals (Sweden)

    Renata de Oliveira Cartaxo

    2013-06-01

    Full Text Available Objetivo: Descrever, a partir do Sistema Integrado de Informações Penitenciárias – Infopen, aspectos da estrutura prisional nacional, características dos apenados e perfil dos profissionais existentes para garantir o preceito constitucional de assistência à saúde. Métodos: Estudo descritivo, de base documental, realizado a partir de dados secundários disponíveis no Sistema Integrado de Informações Penitenciárias, no qual analisaram-se a estrutura carcerária brasileira, o perfil do apenado no que tange a características pessoais e do crime cometido, e os profissionais envolvidos na assistência à saúde. Resultados: Constata-se que existem 298.275 vagas, ocupadas por 496.251 presos nos 1.857 estabelecimentos penais. No tocante ao perfil dos presos, verifica-se que 92,3% (461.444 são do sexo masculino, na faixa etária entre 18 e 24 anos (25,6% - 126.929, da cor parda (36,7% - 82.354, comensino fundamental incompleto (40,7% - 201.938, que cometeram, principalmente, o crime de tráfico de entorpecentes (23,5% - 100.648. Quanto à composição da equipe de assistência à saúde, evidencia-se um total de 5.132 profissionais registrados no sistema. Conclusão: Constata-se, a partir do sistema integrado de informações penitenciárias, que a estrutura carcerária brasileira se caracteriza por apresentar um déficit de vagas, ocasionada pelasuperlotação e/ou saturação dos estabelecimentos existentes, o que dificulta, em especial, a garantia do atendimento às necessidades de saúde dos apenados.

  7. Asymmetric condensed dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Anthony; Diez-Tejedor, Alberto, E-mail: aguirre@scipp.ucsc.edu, E-mail: alberto.diez@fisica.ugto.mx [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA, 95064 (United States)

    2016-04-01

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

  8. RELAÇÕES DE PODER E ESTRUTURA ORGANIZACIONAL EM WEBER E CHIAVENATO

    OpenAIRE

    de Souza, Caio Calmon Vinícius; Esteves, Camila Reynaud; de Souza, Djalma; Oliveira, Jéssica

    2012-01-01

    O presente artigo tem por objetivo discutir a relação entre poder e estrutura organizacional buscando apontar a importância das relações de poder para a estruturação da organização. Para isso recorreu-se às contribuições de Max Weber (1979) e de Chiavenato (2003), ambos teóricos que trataram de questões envolvendo poder e estrutura organizacional. 

  9. Estrutura de capitais da Indústria Transformadora Portuguesa

    OpenAIRE

    Gameiro, João Manuel Martins da Costa

    2015-01-01

    A estrutura de capitais tem assumido nas últimas décadas um relevante interesse na literatura financeira. Prova disso, são os vários estudos que têm surgido desde a publicação do trabalho pioneiro de Modigliani & Miller (1958). Apesar de grande parte dos estudos incidirem sobre as grandes empresas, são já conhecidos, ainda que em pequena escala, alguns estudos que se focalizam no universo das micro, pequenas e médias empresas. O presente trabalho tem como objetivo estudar os determinantes ...

  10. A estrutura retórica do verbete Spinoza

    Directory of Open Access Journals (Sweden)

    Marilena Chaui

    2009-12-01

    Full Text Available Propomos uma análise do verbete "Spinoza" do Dictionnaire Historique et Critique salientando a estrutura retórica do texto, em cujo centro se encontra a nova figura do ateu, construída por Bayle, o ateu especulativo ou "o ateu de sistema".The paper presents a study of the rhetorical framework of the article "Spinoza" in Bayle's Dictionnaire Historique et Critique and the new image of the atheist as athée de système.

  11. Comportamento dinâmico de um modelo simples solo-estrutura

    OpenAIRE

    Gonçalves, Fábio André Vaz

    2012-01-01

    Dissertação para obtencão do Grau de Mestre em Engenharia Civil - Perfil Estruturas O comportamento de uma estrutura sujeita a cargas dinâmicas depende de características como a massa, a rigidez dos vários elementos e da capacidade de dissipação de energia. A resposta dinâmica da estrutura apoiada num solo depende das propriedades dinâmicas dos dois sistemas. A resposta do sistema é influenciada pelos efeitos de interacção solo-estrutura. Nesta dissertação estudou-se um m...

  12. Highly selective condensation of biomass-derived methyl ketones as a source of aviation fuel.

    Science.gov (United States)

    Sacia, Eric R; Balakrishnan, Madhesan; Deaner, Matthew H; Goulas, Konstantinos A; Toste, F Dean; Bell, Alexis T

    2015-05-22

    Aviation fuel (i.e., jet fuel) requires a mixture of C9 -C16 hydrocarbons having both a high energy density and a low freezing point. While jet fuel is currently produced from petroleum, increasing concern with the release of CO2 into the atmosphere from the combustion of petroleum-based fuels has led to policy changes mandating the inclusion of biomass-based fuels into the fuel pool. Here we report a novel way to produce a mixture of branched cyclohexane derivatives in very high yield (>94 %) that match or exceed many required properties of jet fuel. As starting materials, we use a mixture of n-alkyl methyl ketones and their derivatives obtained from biomass. These synthons are condensed into trimers via base-catalyzed aldol condensation and Michael addition. Hydrodeoxygenation of these products yields mixtures of C12 -C21 branched, cyclic alkanes. Using models for predicting the carbon number distribution obtained from a mixture of n-alkyl methyl ketones and for predicting the boiling point distribution of the final mixture of cyclic alkanes, we show that it is possible to define the mixture of synthons that will closely reproduce the distillation curve of traditional jet fuel. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Estruturas elásticas e fadiga muscular

    Directory of Open Access Journals (Sweden)

    Gláucia Andreza Kronbauer

    2013-06-01

    Full Text Available A fadiga muscular pode ser definida pela incapacidade de manter certa tarefa ao longo do tempo; os mecanismos neuromusculares e metabólicos envolvidos na contração muscular estão diretamente associados a esse fenômeno. Este estudo bibliográfico busca descrever as alterações nos elementos contráteis e elásticos envolvidos na contração muscular e sua relação com o desempenho na locomoção. As estruturas contráteis são aquelas que desenvolvem força ativa com gasto de energia metabólica - mecanismo de pontes cruzadas; as elásticas são aquelas que oferecem resistência mecânica ao alongamento sem custo energético - força passiva - e conservam energia elástica para uma nova contração. Após a análise de ambas, é possível afirmar que a fadiga muscular está associada à função das estruturas contráteis e elásticas.

  14. Soft Condensed Matter

    International Nuclear Information System (INIS)

    Jones, Richard A L

    2002-01-01

    The author states in the preface of the book that the aim is '...to give a unified overview of the various aspects of the physics of soft condensed matter'. The book succeeds in fulfilling this aim in many respects. The style is fluent and concise and gives the necessary explanations to make its content understandable to people with some knowledge of the basic principles of physics. The content of the book is complete enough to give a panoramic view of the landscape of soft condensed matter. The first two chapters give, respectively, a short introduction and a presentation of forces, energies and timescales, giving a general overview and pointing out the particular importance of different aspects such as timescales, which are much more important in soft condensed matter than in traditional or 'hard' condensed matter. The next chapter, devoted to phase transition, recalls that the equilibrium between two phases is controlled by free energy considerations. Spinodal decomposition is presented as a counterpart of nucleation and growth. Again, characteristic length scales are considered and applied to a phase separation mixture of polymers in a common solvent. The following three chapters are devoted respectively to specific topics: colloidal dispersion, polymers and gelation. The stability and phase behaviour of colloids are related to the interaction between colloidal particles. Properties of colloidal crystals as well as colloidal dispersion are depicted in terms of stabilization of crystalline colloids. The flow properties of colloidal dispersion are presented in terms of free energy minimization and the structure of the dispersion. After a brief introduction to polymer chemistry and architecture, the coil-globule transition is discussed. Viscoelasticity of polymers is described and discussed by introducing the notion of entanglement. This leads to the introduction of the tube model and the theory of reptation. The sol-gel transition is presented phenomenologically

  15. Condensed Matter Nuclear Science

    Science.gov (United States)

    Biberian, Jean-Paul

    2006-02-01

    1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research

  16. The condensed matter physics

    International Nuclear Information System (INIS)

    Sapoval, B.

    1988-01-01

    The 1988 progress report of the laboratory of the Condensed Matter Physics (Polytechnic School, France), is presented. The Laboratory activities are related to the physics of semiconductors and disordered phases. The electrical and optical properties of the semiconductors, mixed conductor, superionic conductors and ceramics, are studied. Moreover, the interfaces of those systems and the sol-gel inorganic polymerization phenomena, are investigated. The most important results obtained, concern the following investigations: the electrochemical field effect transistor, the cathodoluminescence, the low energy secondary electrons emission, the fluctuations of a two-dimensional diffused junction and the aerogels [fr

  17. Topology in Condensed Matter

    CERN Document Server

    Monastyrsky, M I

    2006-01-01

    This book reports new results in condensed matter physics for which topological methods and ideas are important. It considers, on the one hand, recently discovered systems such as carbon nanocrystals and, on the other hand, new topological methods used to describe more traditional systems such as the Fermi surfaces of normal metals, liquid crystals and quasicrystals. The authors of the book are renowned specialists in their fields and present the results of ongoing research, some of it obtained only very recently and not yet published in monograph form.

  18. Ice condenser experimental plan

    International Nuclear Information System (INIS)

    Kannberg, L.D.; Piepel, G.F.; Owczarski, P.C.; Liebetrau, A.M.

    1986-01-01

    An experimental plan is being developed to validate the computer code ICEDF. The code was developed to estimate the extent of aerosol retention in the ice compartments of pressurized water reactor ice condenser containment systems during severe accidents. The development of the experimental plan began with review of available information on the conditions under which the code will be applied. Computer-generated estimates of thermohydraulic and aerosol conditions entering the ice condenser were evaluated and along with other information, used to generate design criteria. The design criteria have been used for preliminary test assembly design and for generation of statistical test designs. Consideration of the phenomena to be evaluated in the testing program, as well as equipment and measurement limitations, have led to changes in the design criteria and to subsequent changes in the test assembly design and statistical test design. The overall strategy in developing the experimental plan includes iterative generation and evaluation of candidate test designs using computer codes for statistical test design and ICEDF for estimation of experimental results. Estimates of experimental variability made prior to actual testing will be verified by replicate testing at preselected design points

  19. Ferminoic physics in dipolariton condensates.

    Science.gov (United States)

    Su, Jung-Jung; Kim, Na Young; Yamamoto, Yoshihisa; Macdonald, Allan H

    2014-03-21

    An exciton polariton is an extremely light bosonic quasiparticle that is composed of an exciton and a photon. We report on a theoretical study of exciton-polariton condensation in a system with tunnel-coupled quantum wells. Because their excitons can carry an electric dipole moment, these systems have been referred to as dipolariton condensates. We use a fermionic mean-field theory that can address quantum well and other internal exciton degrees of freedom to describe the new physics present in dipolariton condensates. We find that the role of underlying fermonic degrees of freedom is enhanced and predict that metallic condensates can occur at high carrier densities.

  20. A estrutura do sentido: Goldstein e Merleau-Ponty

    Directory of Open Access Journals (Sweden)

    Claudinei Aparecido de Freitas da Silva

    2012-12-01

    Full Text Available Ao reatar o elo mais profundo entre a psicologia e a filosofia, Merleau-Ponty revisita a obra clínica de Kurt Goldstein (1878-1965, reavivando, em especial, seu contributo fenomenológico. As noções de "estrutura" (Gestalt e "sentido" são, aqui, agenciadas quanto a uma compreensão mais integral do comportamento, da vida e da linguagem; alcance que Goldstein obtém, ao estudar os diferentes distúrbios linguísticos, na contramão das teorias intelectualistas e empiristas, essencialmente causais. Ao retomar esse inventário crítico, Merleau-Ponty atenta para o caráter original, dinâmico e, sobretudo, ontológico dessa proposta.

  1. Estrutura populacional da raça Girolando.

    OpenAIRE

    CANAZA-CAYO, A. W.; LOPES, P. S.; SILVA, M. V. G. B.; COBUCI, J. A.; TORRES, R. de A.; MARTINS, M. F.; ARBEX, W. A.

    2015-01-01

    O objetivo neste estudo foi avaliar a estrutura genética da população de bovinos da raça Girolando no Brasil. Analisou-se o arquivo de pedigree de 26.969 animais, composto de 3.031 machos e 23.938 fêmeas. O nível de conteúdo de informação do pedigree na geração atual foi 61%, mostrando ser de qualidade moderada. O coeficiente de endogamia médio e o coeficiente de relação médio da população Girolando foram 0,1...

  2. As estruturas reflexivas no português afro-brasileiro

    OpenAIRE

    Souza, Jurgen Alves de

    2013-01-01

    Vários estudos linguísticos a respeito das estruturas ditas reflexivas presentes no português falado no Brasil têm revelado algumas características que parecem ser traços típicos do português popular brasileiro. Tais estudos, porém, não consideraram o contato linguístico ocorrido no período da colonização brasileira – destacadamente o contato do português com as línguas africanas – como uma explicação provável para que se imprimissem essas marcas no processo de reflexivização utilizado na fal...

  3. Estrutura de mercado e tendências da atividade comercial

    Directory of Open Access Journals (Sweden)

    Jefferson Mariano

    2007-11-01

    Full Text Available O presente artigo busca realizar uma caracterização do setor comercial, com ênfase na RMSP, destacando o processo de concentração, evidenciado principalmente no segmento de hiper e supermercados. Na primeira seção, busca-se ilustrar o processo de concentração em alguns segmentos do comércio varejista, à luz das teorias de estrutura de mercado. Na segunda, apresenta se um painel com o perfil dessa atividade econômica, com informações agregadas para Brasil, Estado de São Paulo e Região Metropolitana de São Paulo. Na terceira, são apontadas as tendências e perspectivas do setor.

  4. Estruturas elásticas e fadiga muscular

    OpenAIRE

    Kronbauer, Gláucia Andreza; Castro, Flávio Antônio de Souza

    2013-01-01

    A fadiga muscular pode ser definida pela incapacidade de manter certa tarefa ao longo do tempo; os mecanismos neuromusculares e metabólicos envolvidos na contração muscular estão diretamente associados a esse fenômeno. Este estudo bibliográfico busca descrever as alterações nos elementos contráteis e elásticos envolvidos na contração muscular e sua relação com o desempenho na locomoção. As estruturas contráteis são aquelas que desenvolvem força ativa com gasto de energia metabólica - mecanism...

  5. Busca de estruturas em grandes escalas em altos redshifts

    Science.gov (United States)

    Boris, N. V.; Sodré, L., Jr.; Cypriano, E.

    2003-08-01

    A busca por estruturas em grandes escalas (aglomerados de galáxias, por exemplo) é um ativo tópico de pesquisas hoje em dia, pois a detecção de um único aglomerado em altos redshifts pode por vínculos fortes sobre os modelos cosmológicos. Neste projeto estamos fazendo uma busca de estruturas distantes em campos contendo pares de quasares próximos entre si em z Â3 0.9. Os pares de quasares foram extraídos do catálogo de Véron-Cetty & Véron (2001) e estão sendo observados com os telescópios: 2,2m da University of Hawaii (UH), 2,5m do Observatório de Las Campanas e com o GEMINI. Apresentamos aqui a análise preliminar de um par de quasares observado nos filtros i'(7800 Å) e z'(9500 Å) com o GEMINI. A cor (i'-z') mostrou-se útil para detectar objetos "early-type" em redshifts menores que 1.1. No estudo do par 131046+0006/J131055+0008, com redshift ~ 0.9, o uso deste método possibilitou a detecção de sete objetos candidatos a galáxias "early-type". Num mapa da distribuição projetada dos objetos para 22 escala. Um outro argumento em favor dessa hipótese é que eles obedecem uma relação do tipo Kormendy (raio equivalente X brilho superficial dentro desse raio), como a apresentada pelas galáxias elípticas em z = 0.

  6. Microgravity condensing heat exchanger

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

    2011-01-01

    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  7. Bose-Einstein Condensation

    International Nuclear Information System (INIS)

    Jaksch, D

    2003-01-01

    The Gross-Pitaevskii equation, named after one of the authors of the book, and its large number of applications for describing the properties of Bose-Einstein condensation (BEC) in trapped weakly interacting atomic gases, is the main topic of this book. In total the monograph comprises 18 chapters and is divided into two parts. Part I introduces the notion of BEC and superfluidity in general terms. The most important properties of the ideal and the weakly interacting Bose gas are described and the effects of nonuniformity due to an external potential at zero temperature are studied. The first part is then concluded with a summary of the properties of superfluid He. In Part II the authors describe the theoretical aspects of BEC in harmonically trapped weakly interacting atomic gases. A short and rather rudimentary chapter on collisions and trapping of atomic gases which seems to be included for completeness only is followed by a detailed analysis of the ground state, collective excitations, thermodynamics, and vortices as well as mixtures of BECs and the Josephson effect in BEC. Finally, the last three chapters deal with topics of more recent interest like BEC in optical lattices, low dimensional systems, and cold Fermi gases. The book is well written and in fact it provides numerous useful and important relations between the different properties of a BEC and covers most of the aspects of ultracold weakly interacting atomic gases from the point of view of condensed matter physics. The book contains a comprehensive introduction to BEC for physicists new to the field as well as a lot of detail and insight for those already familiar with this area. I therefore recommend it to everyone who is interested in BEC. Very clearly however, the intention of the book is not to provide prospects for applications of BEC in atomic physics, quantum optics or quantum state engineering and therefore the more practically oriented reader might sometimes wonder why exactly an equation is

  8. Supersymmetry is afraid of condensates

    Directory of Open Access Journals (Sweden)

    G. Domokos

    1983-01-01

    Full Text Available Supersymmetry is never broken by pair condensates of chiral superfields: the supersymmetry breaking part of Green's functions satisfies an equation which always has an identically vanishing solution. Hence any phase containing pair condensates is unstable due to its positive vacuum energy.

  9. A Combined DFT and NMR Investigation of the Zinc Organometallic Intermediate Proposed in the Syn-Selective Tandem Chain Extension-Aldol Reaction of β-Keto Esters

    Science.gov (United States)

    Aiken, Karelle S.; Eger, Wilhelm A.; Williams, Craig M.; Spencer, Carley M.

    2012-01-01

    The tandem chain extension-aldol (TCA) reaction of β-keto esters provides a α-substituted γ-keto ester with an average syn:anti selectivity of 10:1. It is proposed that the reaction proceeds via a carbon-zinc bound organometallic intermediate potentially bearing mechanistic similarity to the Reformatsky reaction. Evidence, derived from control Reformatsky reactions and a study of the structure of the TCA intermediate utilizing DFT methods and NMR-spectroscopy, suggests the γ-keto group of the TCA intermediate plays a significant role in diastereoselectivity observed in this reaction. Such coordination effects have design implications for future zinc mediated reactions. PMID:22703563

  10. Curiosities about aldollic reaction used as a key step in the Brazilian synthesis of pteridic acids A and B; Curiosidades sobre a reacao aldolica utilizada como etapa chave na sintese brasileira dos acidos pteridicos A e B

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Luiz C.; Salles Junior, Airton G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2010-07-01

    This work describes an overview of our synthesis of pteridic acids A and B and discloses some interesting results related to the lithium enolate-mediated aldol reaction used as key step to set up the C5-C15 fragment of these natural products. This first example, as far we know, of an aldol reaction between a chiral enolate of a (Z) enone and a chiral aldehyde has driven us to a series of experiments showing the remarkable relation between enolization selectivity and reaction conditions. (author)

  11. RELAÇÕES DE PODER E ESTRUTURA ORGANIZACIONAL EM WEBER E CHIAVENATO

    Directory of Open Access Journals (Sweden)

    Caio Calmon Vinícius de Souza

    2012-03-01

    Full Text Available O presente artigo tem por objetivo discutir a relação entre poder e estrutura organizacional buscando apontar a importância das relações de poder para a estruturação da organização. Para isso recorreu-se às contribuições de Max Weber (1979 e de Chiavenato (2003, ambos teóricos que trataram de questões envolvendo poder e estrutura organizacional.

  12. Determinantes da folga organizacional em uma empresa com estrutura descentralizada.

    Directory of Open Access Journals (Sweden)

    Ilse Maria Beuren

    2015-08-01

    Full Text Available O objetivo do estudo é identificar os determinantes da folga organizacional em uma empresa com estrutura descentralizada, com ênfase no modo como os controllers das unidades de negócios afetam a folga. Foi realizada uma pesquisa descritiva com abordagem quantitativa, por meio de survey, utilizando o instrumento de pesquisa concebido por Indjejikian e Matëjka (2006, que se constitui de dois questionários, um para o gestor e outro para o controller de cada UN. A empresa objeto de estudo apresenta estrutura descentralizada com 45 UNs, das quais 32 responderam aos questionários. Os resultados da pesquisa indicam que as metas de desempenho, quando o crescimento das UNs é provocado pelo aumento das vendas e do market share, com sacrifício do retorno sobre o investimento no curto e médio prazos, são mais fáceis de alcançar e permitem maior folga organizacional do que em situações de UNs mais estáveis. Também indicam que a folga organizacional é maior em ambientes caracterizados por maior assimetria de informação entre a holding e os gestores das UNs, definidos pelo foco do controller da UN. Os resultados dos testes da relação entre as variáveis foco do controller da UN e folga organizacional evidenciam que os controllers das UNs priorizam o apoio à tomada de decisão na UN, em detrimento de suas responsabilidades com o sistema de controle gerencial corporativo. Quanto maior o tempo de atuação do controller na UN, maior é a sua dedicação às responsabilidades relacionadas à gestão da UN em detrimento do foco nas tarefas da holding. Conclui-se que a relação constatada nesta pesquisa entre o nível de folga organizacional e o foco dos controllers das UNs se coaduna com aquela enunciada no estudo de referência. De maneira geral, os resultados das análises estão alinhados com os da pesquisa de Indjejikian e Matëjka (2006, consideradas as limitações de comparabilidade em função das diferenças amostrais.

  13. Condenser retubing-criteria manual

    International Nuclear Information System (INIS)

    Impagliazzo, A.M.; Bell, R.J.; Curlett, P.L.; Gordon, H.L.

    1982-05-01

    The objective of this document is to provide engineering assistance to utilities involved in retubing steam surface condensers with corrosion-resistant materials, such as titanium, and the recently developed high alloy pit-resistant steels. Field tests and recent operating experience have shown titanium and at least one of the high alloy pit-resistant steels to be virtually immune to the usual forms of corrosion occurring in steam surface condensers. This, together with the trend toward elimination of copper alloys in the circulating water system, has caused many utilities to retube their condensers with these materials

  14. Bose condensation in (random traps

    Directory of Open Access Journals (Sweden)

    V.A. Zagrebnov

    2009-01-01

    Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.

  15. Condensation coefficient of water in a weak condensation state

    International Nuclear Information System (INIS)

    Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

    2008-01-01

    The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

  16. Condensation coefficient of water in a weak condensation state

    Science.gov (United States)

    Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

    2008-07-01

    The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

  17. A estrutura fatorial do Teste de Criatividade Figural Infantil

    Directory of Open Access Journals (Sweden)

    Tatiana de Cássia Nakano

    Full Text Available Com o objetivo de investigar evidências de validade do Teste de Criatividade Figural Infantil, instrumento que visa avaliar 12 características criativas (Fluência, Flexibilidade, Elaboração, Originalidade, Expressão de Emoção, Perspectiva Incomum, Perspectiva Interna, Fantasia, Movimento, Uso de Contexto, Extensão de Limites e Títulos Expressivos, uma análise fatorial foi realizada visando uma melhor compreensão acerca do agrupamento dessas características. Estudantes de 1a a 8a séries do Ensino Fundamental (n=1253, 599F / 654M responderam ao instrumento. A análise fatorial apontou uma estrutura composta por quatro fatores (enriquecimento de idéias, aspectos cognitivos, emotividade e preparação criativa, que foi adotado como modelo de interpretação do instrumento devido à sua consistência com a literatura científica.

  18. Atitude do Consumidor: Estrutura dos Modelos Teóricos

    Directory of Open Access Journals (Sweden)

    Rafael Barreiros Porto

    2010-10-01

    Full Text Available Este trabalho visa oferecer uma organização de teorias de atitude originada por meio de levantamento bibliográfico da literatura de psicologia do consumidor. O pesquisador de marketing poderá ver algumas limitações e utilidades da medição do constructo - atitude - muitas vezes concebido através de pesquisas acadêmicas com o fim de compreender o processo de compra ou escolha. Pretendeu-se prover explicações sobre as estruturas formadoras de atitudes em modelos teóricos, ofertando uma classificação de ênfase de investigação empírica dos componentes da atitude. Este ensaio propõe uma agenda de pesquisa na área para que novas estratégias de investigação possam ser elaboradas em marketing.DOI: 10.5585/remark.v9i2.2145

  19. Raízes e estruturas da sociedade brasileira

    Directory of Open Access Journals (Sweden)

    Leonor Natividade de Campos Medeiros

    2014-05-01

    Full Text Available Este estudo teve como objetivo conhecer e refletir as raízes e estruturas da sociedade brasileira, na visão de dois grandes pensadores: Sérgio Buarque de Holanda com Raízes do Brasil e Gilberto Freyre com Casa-Grande & Senzala. Holanda dividiu o Brasil em duas fases a primeira da colonização portuguesa e a segunda uma critica ao Estado Novo. Freyre mostra a organização social, política e econômica da época da colonização e desenvolve seus estudos ao final da década de 1920, época em que o ambiente intelectual brasileiro está sob a força do modernismo. Conclui-se que o pensamento de Holanda e Freyre se assemelha em alguns aspectos e diverge em outros.   Sociologia de Freyre; Sociologia de Holanda; Raízes da sociedade brasileira

  20. Efficient, Long-Life Biocidal Condenser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity in manned modules. Condensing surfaces...

  1. Condenser assembly system for an appliance

    Energy Technology Data Exchange (ETDEWEB)

    Litch, Andrew David

    2017-10-17

    An appliance includes a compact condenser assembly formed with at least two separately and independently produced wire on tube condensers. Each of the at least two wire on tube condensers has a condenser inlet and a condenser outlet. The at least two wire on tube condensers are at least substantially locked and positioned in a matingly engaged configuration forming a compact condenser assembly. The at least two wire on tube condensers are configured to be operationally connected in at least one of a parallel configuration, a series configuration, a selectable configuration, and a bypass configuration.

  2. Steam generators, turbines, and condensers. Volume six

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)

  3. OPTIMAL EVAPORATING AND CONDENSING TEMPERATURES ...

    African Journals Online (AJOL)

    ORC) in a hot and humid environment. A theoretical procedure is proposed for the determination of the optimal evaporation temperature (OET) and optimal condensing temperature (OCT) of a subcritical ORC plant, which is based on ...

  4. Solar engineering - a condensed course

    Energy Technology Data Exchange (ETDEWEB)

    Broman, Lars

    2011-11-15

    The document represents the material covered in a condensed two-week course focusing on the most important thermal and PV solar energy engineering topics, while also providing some theoretical background.

  5. A new synthesis of enantiomerically pure syn-(S)-β-hydroxy-α-amino acids via asymmetric aldol reactions of aldehydes with a homochiral Ni(II)-glycine/(S)-BPB Schiff base complex

    NARCIS (Netherlands)

    Belokon, Yuri N.; Kochetkov, Konstantin A.; Ikonnikov, Nikolai S.; Strelkova, Tatiana V.; Harutyunyan, Syuzanna R.; Saghiyan, Ashot S.

    2001-01-01

    syn-(S)-β-Hydroxy-α-amino acids were synthesised stereoselectively via elaboration of the asymmetric aldol reactions of aldehydes with a chiral Ni(II)-(S)-BPB/glycine Schiff base complex in the presence of equimolar NaH in THF. The stereoselectivity of the reaction was studied as a function of time,

  6. Condensed Matter Nuclear Science

    Science.gov (United States)

    Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

    Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation

  7. Estrutura populacional da raça Girolando

    Directory of Open Access Journals (Sweden)

    Ali William Canaza-Cayo

    2014-11-01

    Full Text Available O objetivo neste estudo foi avaliar a estrutura genética da população de bovinos da raça Girolando no Brasil. Analisou-se o arquivo de pedigree de 26.969 animais, composto de 3.031 machos e 23.938 fêmeas. O nível de conteúdo de informação do pedigree na geração atual foi 61%, mostrando ser de qualidade moderada. O coeficiente de endogamia médio e o coeficiente de relação médio da população Girolando foram 0,11 e 0,13%, respectivamente. O tamanho efetivo da população, considerando a geração completa traçada, foi 188, acima do nível crítico. Do total de 9.457 ancestrais que contribuíram para a população de referência, 457 explicaram 50% da variabilidade genética da população. O número efetivo de fundadores foi 551 e o de ancestrais 393. O intervalo médio de geração foi de 5,26 anos, sendo ligeiramente maior nas trilhas gaméticas mãe-filho e pai-filha. A partir dos coeficientes estimados, pode-se concluir que a endogamia nos rebanhos da raça Girolando foi de pequena magnitude e que as práticas de acasalamento foram adequadas durante o período avaliado. No entanto, é importante continuar com o monitoramento desses coeficientes a fim de prevenir perda de variabilidade genética

  8. Condensation: the new deal; Condensation: la nouvelle donne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-06-01

    The principle of condensation boilers is based on the recovery of the latent heat of the steam generated by the combustion of natural gas. This technology was introduced in France at the end of the 80's but failed in its promise because of the complexity of the equipments available at that time. Today, constructors' offer is more mature and reliable and the context has changed. This technology can conciliate three goals: a mastery of energy consumptions, the comfort of the user and the respect of environment. This meeting organized by the research center of Gaz de France (Cegibat), was a good opportunity to makes a status of the market of individual condensation systems in France and in Europe, to present the situation of this technology today and the 10 golden rules for the fitting and maintenance of individual condensation boilers, and to present some technical references, examples and results of today's offer. (J.S.)

  9. Research progress of control of condensate depression for condenser

    Science.gov (United States)

    Liu, Ying; Liang, Run; Li, Fengyu

    2017-08-01

    It is introduced that significance and structure of the condensate depression control system. In accordance with controller devised procedure, we analyze and elaborate how to construct the lumped parameter and dynamic mathematical model which possesses distinct physics significance. Neural network model being called black-box model is also introduced. We analyze and contrast the control technique of condensate depression as conventional PI control, fuzzy PI control and fuzzy control. It is indicated that if the controller of condensate depression were devised inappropriate, while the steam discharged of turbine varying by a large margin, would result in the rotation rate of cooling water circulating pump accelerating at a great lick even to trigger the galloping danger which is less impressive for the units operating safely.

  10. Introduction. Cosmology meets condensed matter.

    Science.gov (United States)

    Kibble, T W B; Pickett, G R

    2008-08-28

    At first sight, low-temperature condensed-matter physics and early Universe cosmology seem worlds apart. Yet, in the last few years a remarkable synergy has developed between the two. It has emerged that, in terms of their mathematical description, there are surprisingly close parallels between them. This interplay has been the subject of a very successful European Science Foundation (ESF) programme entitled COSLAB ('Cosmology in the Laboratory') that ran from 2001 to 2006, itself built on an earlier ESF network called TOPDEF ('Topological Defects: Non-equilibrium Field Theory in Particle Physics, Condensed Matter and Cosmology'). The articles presented in this issue of Philosophical Transactions A are based on talks given at the Royal Society Discussion Meeting 'Cosmology meets condensed matter', held on 28 and 29 January 2008. Many of the speakers had participated earlier in the COSLAB programme, but the strength of the field is illustrated by the presence also of quite a few new participants.

  11. Condensational theory of stationary tornadoes

    International Nuclear Information System (INIS)

    Makarieva, A.M.; Gorshkov, V.G.; Nefiodov, A.V.

    2011-01-01

    Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated. -- Highlights: → Water vapor condensation causes a logarithmic drop of air pressure towards tornado center. → The first ever theoretical description of tornado velocities is obtained. → The maximum vortex velocity grows logarithmically with decreasing tornado eye radius. → Air motion with high velocities can only develop in sufficiently large condensation areas.

  12. Scrutinizing the pion condensed phase

    Energy Technology Data Exchange (ETDEWEB)

    Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)

    2017-02-15

    When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)

  13. Asymmetric catalysis in aqueous media: use of metal-chiral crown ethers as efficient chiral Lewis acid catalysts in asymmetric aldol reactions

    Directory of Open Access Journals (Sweden)

    Shu Kobayashi

    2001-01-01

    Full Text Available Metal-chiral crown ether complexes have been developed as efficient chiral Lewis acid catalysts for asymmetric aldol reactions of silyl enol ethers with aldehydes in aqueous media. While many excellent catalytic asymmetric reactions have been developed recently, most of them have to be carried out under strictly anhydrous conditions in organic solvents. This is probably due to the instability of many catalysts and/or intermediates in the presence of even a small amount of water. To address this issue, we searched for metal-crown ether complexes on the basis of our "multi-coordination" hypothesis, and found that lead(II and lanthanide(III catalysts worked well as chiral Lewis acids in aqueous media. To the best of our knowledge, these are the first examples of chiral crown-based Lewis acids that can be successfully used in catalytic asymmetric reactions. The catalysts have been characterized by X-ray diffraction, and their unique structures as chiral catalysts have been revealed. Use of water as a solvent is essential in these asymmetric catalysis, and the role of water on these reactions to explain the high reactivity and selectivity has been suggested. Another important point is that kinetic studies have shown the possibility that these types of crown ether complexes would be suitable as chiral catalysts employed in aqueous media. In addition, although the catalytic asymmetric aldol reactions are one of the most powerful carbon-carbon bond-forming methodologies and several successful examples have been reported, the use of aprotic anhydrous solvents and low reaction temperatures (-78 °C has been needed in almost all successful cases. On the other hand, the present reactions proceeded smoothly at -10-0 °C in water-alcohol solutions while retaining high levels of diastereo- and enantioselectivities.

  14. Oportunismo como determinante da estrutura de capital: Um estudo de caso em nanotecnologia

    Directory of Open Access Journals (Sweden)

    Milena de Cassia Rocha

    2017-06-01

    Full Text Available A discussão sobre os determinantes da estrutura de capital é algo que vem sendo realizado há algum tempo. Contudo, é observado uma lacuna a respeito do tema em empresas de nanotecnologia, assim como trabalhos que enfoquem a ideia do oportunismo como determinante da estrutura de capital. Sendo assim, o presente artigo traz uma discussão sobre a ideia do oportunismo como determinante da estrutura de capital em empresas de nanotecnologia no Brasil. Para tal, foi realizado um estudo de caso abordando aspectos ligados a estrutura de capital adotada, a verificação da utilização de determinadas teorias sobre o tema e a relevância de algumas fontes. Foi observado que a empresa analisada utiliza a ideia do oportunismo como determinante da estrutura de capital devido aos fatores relacionados ao custo das fontes e as exigências por parte dos credores. Assim, em momentos em que os custos e as exigências são aceitáveis, para a empresa, se opta por tais fontes.

  15. The chiral condensate in matter

    International Nuclear Information System (INIS)

    Brockmann, R.; Weise, W.

    1995-01-01

    The change of the chiral condensate in dense matter is discussed. Especially the higher order terms in the density of nuclear matter are evaluated (in the relativistic Brueckner-Hartree-Fock approach). Implications for nuclear physics and relativistic heavy ion collisions are discussed, such as the strong Dirac scalar mean field that results from the density dependence of . (orig.)

  16. KAON CONDENSATION IN NEUTRON STARS.

    Energy Technology Data Exchange (ETDEWEB)

    RAMOS,A.; SCHAFFNER-BIELICH,J.; WAMBACH,J.

    2001-04-24

    We discuss the kaon-nucleon interaction and its consequences for the change of the properties of the kaon in the medium. The onset of kaon condensation in neutron stars under various scenarios as well its effects for neutron star properties are reviewed.

  17. Approaching Bose-Einstein Condensation

    Science.gov (United States)

    Ferrari, Loris

    2011-01-01

    Bose-Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial…

  18. Modeling of Kerena Emergency Condenser

    Science.gov (United States)

    Bryk, Rafał; Schmidt, Holger; Mull, Thomas; Wagner, Thomas; Ganzmann, Ingo; Herbst, Oliver

    2017-12-01

    KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA) was built in Karlstein, Germany. The emergency condenser (EC) system transfers heat from the reactor pressure vessel (RPV) to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA). The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

  19. Modeling of Kerena Emergency Condenser

    Directory of Open Access Journals (Sweden)

    Bryk Rafał

    2017-12-01

    Full Text Available KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA was built in Karlstein, Germany. The emergency condenser (EC system transfers heat from the reactor pressure vessel (RPV to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA. The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

  20. ESTRUTURA DO SOLO SOB FEIJÃO IRRIGADO E DIFERENTES MANEJO DO SOLO

    OpenAIRE

    Lorena Adriana de Gennaro; Zigomar Menezes de Souza; Laura Fernanda Simões da Silva; Miguel Cooper; Milton César Costa Campos

    2015-01-01

    O manejo agrícola influencia a estrutura do solo, modificando os atributos físicos e o comportamento hídrico do solo. O objetivo deste trabalho foi avaliar os efeitos da semeadura direta (SD) e do preparo convencional (PC) sobre a estrutura do solo, por meio de atributos físicos e da distribuição dos poros, utilizando imagens digitais 2-D. O estudo foi realizado em um Latossolo Vermelho distroférrico com delineamento de blocos casualizados. A densidade do so...

  1. Estudo de ligações em estruturas mistas de concreto-madeira

    OpenAIRE

    Elias Antonio Nicolas

    2001-01-01

    Resumo: Esta pesquisa se refere ao estudo do comportamento mecânico de conectores empregados em estruturas mistas de concreto e madeira, estruturas estas normalmente utilizadas em construções civis tais como pontes, pisos e coberturas residenciais. Neste sentido, foi realizado um estudo teórico-experimental sobre os conectores onde se determinou o valor do módulo de deslizamento (K) através de curvas cargas x deslizamentos obtidas a partir ensaios de laboratório. Os corpos-de-prova foram mold...

  2. ESTRUTURA FAMILIAR E GRAVIDEZ NA ADOLESCÊNCIA: UM ENFOQUE SISTÊMICO

    OpenAIRE

    MARY LÚCIA ADLER EWERTON

    2010-01-01

    Estudo qualitativo, tendo como objetivo abordar a relação existente entre estrutura familiar e gravidez na adolescência em um enfoque sistêmico. Parte do pressuposto que a estrutura familiar atua no comportamento dos seus membros influenciando em suas decisões. A pesquisa foi realizada no Núcleo de Atenção à Saúde da Adolescente (NASA), da Unidade Materno-Infantil, sendo iniciada após a aprovação do Comitê de Ética em Pesquisa HUUFMA. O critério de inclusão adotado foi ter a fa...

  3. Falhas de estruturas de aço soldadas devido a reduzida ductilidade

    Directory of Open Access Journals (Sweden)

    Ivan Guerra Machado

    2013-12-01

    Full Text Available O principal propósito deste artigo é demonstrar para os (as engenheiros(as projetistas e de soldagem, que numa estrutura de aço estrutural soldada a ductilidade possui importância equivalente ou ainda maior do que a resistência e a rigidez. Porém, o elevado nível requerido para a ductilidade não pode ser somente dos metais base e de solda. A análise tem que ser abrangente, envolvendo todos os componentes e também a estrutura completa.

  4. Desenvolvimento de metodologia para identificação modal automática de estruturas.

    OpenAIRE

    Cardoso, Rharã de Almeida

    2015-01-01

    Programa de Pós Graduação em Engenharia Civil. Departamento de Engenharia Civil, Escola de Minas, Universidade Federal de Ouro Preto. O monitoramento da integridade estrutural (SHM – Structural Health Monitoring) de estruturas é de grande importância prática para engenharia civil. Grandes obras como a ponte Rio-Niterói, no Brasil, a ponte Z24, na Suíça, ou o viaduto de Millau, na França, são monitoradas há algum tempo. De fato, algumas estruturas são monitoradas 24 horas por dia,7 dias por...

  5. POTENTIAL DIMETHYLMERCURY CONCENTRATION IN WATER & ORGANIC CONDENSATE

    Energy Technology Data Exchange (ETDEWEB)

    MEACHAM, J.E.

    2004-12-28

    This document bounds potential dimethylmercury concentration in water or organic condensate that might form in ventilation systems or cooler tank regions. Dimethylmercury concentrations were extremely low and would be below drinking water standards in the water condensate.

  6. Some concepts in condensed phase chemical kinetics

    International Nuclear Information System (INIS)

    Adelman, S.A.

    1986-01-01

    Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms

  7. Pion condensation and neutron star dynamics

    International Nuclear Information System (INIS)

    Kaempfer, B.

    1983-01-01

    The question of formation of pion condensate via a phase transition in nuclear matter, especially in the core of neutron stars is reviewed. The possible mechanisms and the theoretical restrictions of pion condensation are summarized. The effects of ultradense equation of state and density jumps on the possible condensation phase transition are investigated. The possibilities of observation of condensation process are described. (D.Gy.)

  8. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.

    Science.gov (United States)

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim

    2013-11-01

    This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.

  9. Condensed matter analogues of cosmology

    Science.gov (United States)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

  10. Charge Screening in a Charged Condensate

    International Nuclear Information System (INIS)

    Gabadadze, Gregory; Rosen, Rachel A.

    2009-01-01

    We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.

  11. Computations for a condenser. Experimental results

    International Nuclear Information System (INIS)

    Walden, Jean.

    1975-01-01

    Computations for condensers are presented with experimental results. The computations are concerned with the steam flux at the condenser input, and inside the tube bundle. Experimental results are given for the flux inside the condenser sleeve and the flow passing through the tube bundle [fr

  12. Direct, nondestructive observation of a Bose condensate

    NARCIS (Netherlands)

    Andrews, M.R.; Mewes, M.O.; van Druten, N.J.; Durfee, D.S.; Kurn, D.M.; Ketterle, W.

    1996-01-01

    The spatial observation of a Bose condensate is reported. Dispersive light scattering was used to observe the separation between the condensed and normal components of the Bose gas inside a magnetic trap. This technique is nondestructive, and about a hundred images of the same condensate can be

  13. Droplet size distribution in condensing flow

    NARCIS (Netherlands)

    Sidin, R.S.R.

    2009-01-01

    In this thesis, the problem of predicting the droplet size distribution in condensing ow is in- vestigated numerically and analytically. The work focuses on two types of problems: one where condensation occurs during the transonic expansion of a vapor-mixture, and a second one where condensation

  14. Modelling of film condensation in presence of non condensable gases

    International Nuclear Information System (INIS)

    Genevieve Geffraye; Dominique Bestion; Vladimir Kalitvianski

    2005-01-01

    Full text of publication follows: This paper presents recent developments in the modelling of the condensation due to heat removal from a wall with a possible presence of hydrogen, nitrogen, or air. This work is mainly concerned with nuclear reactor safety with particular reference to situations related to new reactor design, cold shutdown state and severe accident analysis. Film condensation of steam in presence of nitrogen and helium in a tube has been investigated in the COTURNE experiment in a rather large range of parameters, pressure (from 0.1 to 7 Mpa), heat flux (0.1 to 6 W/cm 2 ), mass fraction of noncondensable gas (0 to 1) and also in presence of superheated steam. The experiment represents a Steam Generator tube of a Pressurised Water Reactor and can simulate both co-current or countercurrent flow of steam and water.The models are implemented in the CATHARE code used for nuclear reactor thermal-hydraulics. The code uses two mass balance equations for liquid and gas, two momentum balance equations for liquid and gas and two energy balance equations for liquid and gas. Additional mass transport equations can be added for each non condensable gas. Heat transfers from wall to liquid film, from liquid to interface and gas to interface are modelled. The liquid film heat transfer coefficient is first investigated in pure saturated steam conditions in the pressure range from 0.1 to 7 Mpa. The CATHARE film condensation model in pure steam conditions is derived from Chen's correlation. Chen proposes a general correlation for the film condensation, covering the wavy-laminar and the turbulent film regimes and taking into account the interfacial friction effect. A large data base of laminar film regime was used including COTURNE data other available data found in the literature. The analysis of these data base suggests an influence of the liquid Reynolds number, according to the Nusselt theory, and also of the Eoetvoes number, with surface tension effects. A

  15. Fundamentals of condensed matter physics

    CERN Document Server

    Cohen, Marvin L

    2016-01-01

    Based on an established course and covering the fundamentals, central areas, and contemporary topics of this diverse field, Fundamentals of Condensed Matter Physics is a much-needed textbook for graduate students. The book begins with an introduction to the modern conceptual models of a solid from the points of view of interacting atoms and elementary excitations. It then provides students with a thorough grounding in electronic structure as a starting point to understand many properties of condensed matter systems - electronic, structural, vibrational, thermal, optical, transport, magnetic and superconductivity - and methods to calculate them. Taking readers through the concepts and techniques, the text gives both theoretically and experimentally inclined students the knowledge needed for research and teaching careers in this field. It features 200 illustrations, 40 worked examples and 150 homework problems for students to test their understanding. Solutions to the problems for instructors are available at w...

  16. Enantioselective Synthesis of α-Methylene-β-hydroxy Carboxylic Acid Derivatives via a Diastereoselective Aldol-β-Elimination Sequence: Application to the C(15)–C(21) Fragment of Tedanolide C

    Science.gov (United States)

    Barth, Roland; Roush, William R.

    2010-01-01

    An enantioselective synthesis of α-methylene-β-hydroxy carboxylic acid derivatives via a highly diastereoselective, one-pot syn-aldol and β-elimination sequence utilizing the chiral β-(phenylselenyl)propionyl imide 15 is described. This new method, which constitutes an alternative to the Baylis-Hillman reaction, has been applied to the synthesis of the C(15)-C(21) fragment of tedanolide C. PMID:20405855

  17. LOFCON-LOFT condenser program

    International Nuclear Information System (INIS)

    Lemmon, E.C.; MacKay, D.B.

    1978-01-01

    LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation

  18. LOFCON-LOFT condenser program

    Energy Technology Data Exchange (ETDEWEB)

    Lemmon, E.C.; MacKay, D.B.

    1978-05-26

    LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation.

  19. Advances in condensed matter optics

    CERN Document Server

    Chen, Liangyao; Jiang, Xunya; Jin, Kuijuan; Liu, Hui; Zhao, Haibin

    2015-01-01

    This book describes some of the more recent progresses and developmentsin the study of condensed matter optics in both theoretic and experimental fields.It will help readers, especially graduate students and scientists who are studying and working in the nano-photonic field, to understand more deeply the characteristics of light waves propagated in nano-structure-based materials with potential applications in the future.

  20. Accelerators for condensed matter research

    International Nuclear Information System (INIS)

    Williams, P.R.

    1990-01-01

    The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

  1. Theory of laminar film condensation

    CERN Document Server

    Fujii, Tetsu

    1991-01-01

    Since the petroleum crisis in the 1970s, a lot of effort to save energy was made in industry, and remarkable achievements have been made. In the research and development concerning thermal energy, however, it was clar­ ified that one of the most important problems was manufacturing con­ densing systems with smaller size and higher performance. To solve this problem we need a method which synthesizes selections_ of the type of con­ denser, cooling tube and its arrangement, assessment of fouling on the cooling surfaces, consideration of transient characteristics of a condenser, etc. The majority of effort, however, has been to devise a surface element which enhances the heat transfer coefficient in condensation of a single or multicomponent vapor. Condensation phenomena are complexly affected by a lot of physical property values, and accordingly the results of theo­ retical research are expressed with several dimensionless parameters. On the other hand, the experimental research is limited to those with som...

  2. Estrutura fatorial da escala de atitudes frente a relacionamentos afetivos estáveis

    Directory of Open Access Journals (Sweden)

    Taciano Lemos Milfont

    Full Text Available O presente estudo visa contribuir para a comprovação da estrutura fatorial da Escala de Atitudes Frente a Relacionamentos Afetivos Estáveis (RAE; Reis, 1995. Participaram da pesquisa 658 estudantes universitários com idade média 19,9 anos (DP=2,5. Análises fatoriais exploratórias e confirmatórias indicaram a existência de uma estrutura multidimensional. Os cinco fatores encontrados (Comprometimento, Edificação, Mutualidade, Envolvimento e Indulgência apresentaram índices de consistência interna satisfatórios (0,68<α<0,83, itens com saturações altas (0,46<λy<0,75 e significativas (p<0,05. Esta estrutura multidimensional apresentou melhores índices de bondade de ajuste (χ2/gl=3,07; GFI=0,91; CFI=0,97; RMSEA=0,056 e foi estatisticamente superior [Δχ2(111=676,69, p<0,001] à estrutura unidimensional. Resultados de correlações com as auto-imagens independente e interdependente (Singelis, 1994, com os valores humanos básicos (Gouveia, 2003, além de diferenças quanto ao sexo, confirmam a validade dos cinco novos fatores.

  3. Universal Themes of Bose-Einstein Condensation

    Science.gov (United States)

    Proukakis, Nick P.; Snoke, David W.; Littlewood, Peter B.

    2017-04-01

    Foreword; List of contributors; Preface; Part I. Introduction: 1. Universality and Bose-Einstein condensation: perspectives on recent work D. W. Snoke, N. P. Proukakis, T. Giamarchi and P. B. Littlewood; 2. A history of Bose-Einstein condensation of atomic hydrogen T. Greytak and D. Kleppner; 3. Twenty years of atomic quantum gases: 1995-2015 W. Ketterle; 4. Introduction to polariton condensation P. B. Littlewood and A. Edelman; Part II. General Topics: Editorial notes; 5. The question of spontaneous symmetry breaking in condensates D. W. Snoke and A. J. Daley; 6. Effects of interactions on Bose-Einstein condensation R. P. Smith; 7. Formation of Bose-Einstein condensates M. J. Davis, T. M. Wright, T. Gasenzer, S. A. Gardiner and N. P. Proukakis; 8. Quenches, relaxation and pre-thermalization in an isolated quantum system T. Langen and J. Schmiedmayer; 9. Ultracold gases with intrinsic scale invariance C. Chin; 10. Berezinskii-Kosterlitz-Thouless phase of a driven-dissipative condensate N. Y. Kim, W. H. Nitsche and Y. Yamamoto; 11. Superfluidity and phase correlations of driven dissipative condensates J. Keeling, L. M. Sieberer, E. Altman, L. Chen, S. Diehl and J. Toner; 12. BEC to BCS crossover from superconductors to polaritons A. Edelman and P. B. Littlewood; Part III. Condensates in Atomic Physics: Editorial notes; 13. Probing and controlling strongly correlated quantum many-body systems using ultracold quantum gases I. Bloch; 14. Preparing and probing chern bands with cold atoms N. Goldman, N. R. Cooper and J. Dalibard; 15. Bose-Einstein condensates in artificial gauge fields L. J. LeBlanc and I. B. Spielman; 16. Second sound in ultracold atomic gases L. Pitaevskii and S. Stringari; 17. Quantum turbulence in atomic Bose-Einstein condensates N. G. Parker, A. J. Allen, C. F. Barenghi and N. P. Proukakis; 18. Spinor-dipolar aspects of Bose-Einstein condensation M. Ueda; Part IV. Condensates in Condensed Matter Physics: Editorial notes; 19. Bose

  4. A estrutura da brincadeira e a regulação das relações

    Directory of Open Access Journals (Sweden)

    Fernando Augusto Ramos Pontes

    Full Text Available A brincadeira tradicional de rua é um fenômeno paradigmático da organização social de crianças e da cultura infantil. O estudo das brincadeiras tradicionais infantis possibilita a investigação de um fenômeno "espontâneo", sem o planejamento adulto e sem o recurso da escrita. Cada brincadeira, em cada cultura, possui uma estrutura peculiar que a define. A estrutura da brincadeira, no geral determina o desenrolar dos acontecimentos no jogo, prevendo padrões, estratégias e sanções típicas. Apesar desta estrutura ter sua origem histórica nas relações, constitui um elemento supra-relacional, ritualizado. Cada característica estrutural, verbalmente codificada, existe independente das relações, é um dos seus determinantes. Na verdade, a estrutura de uma brincadeira não determina totalmente e linearmente as interações entre os sujeitos de modo a eliminar as peculiaridades das relações; a estrutura interage com as relações anteriormente dadas. As interações nas brincadeiras serão fruto do institucionalmente dado e das relações entre seus membros. A partir de exemplos de brincadeiras tradicionais tais como, peteca (bola de gude, papagaio, tratos, elástico e outras, serão analisados aspectos estruturais que condicionam e interagem com as relações. Acredita-se que a investigação de tais fatores seja importante tanto para melhor descrição da brincadeira quanto para compreensão das relações entre os membros do grupo bem como da transmissão da cultura da brincadeira.

  5. Condensation on slippery asymmetric bumps

    Science.gov (United States)

    Park, Kyoo-Chul; Kim, Philseok; Grinthal, Alison; He, Neil; Fox, David; Weaver, James C.; Aizenberg, Joanna

    2016-03-01

    Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be

  6. Quantum tunnelling in condensed media

    CERN Document Server

    Kagan, Yu

    1992-01-01

    The essays in this book deal with of the problem of quantum tunnelling and related behavior of a microscopic or macroscopic system, which interacts strongly with an ""environment"" - this being some form of condensed matter. The ""system"" in question need not be physically distinct from its environment, but could, for example, be one particular degree of freedom on which attention is focussed, as in the case of the Josephson junction studied in several of the papers. This general problem has been studied in many hundreds, if not thousands, of articles in the literature, in contexts as diverse

  7. Análise dos diferentes modelos de estruturação de procurement em empresas de real estate

    OpenAIRE

    Mauricio Bertoldi Sanchez Neves

    2016-01-01

    Percebe-se no mercado brasileiro que a área de suprimentos - Procurement - nas empresas do segmento de real estate de construção civil se apresenta, tanto em termos de estrutura quanto em procedimentos, de diferentes formas. É possível observar estruturas centralizadas responsáveis por toda a gestão na companhia, enquanto há outras em que as obras são autônomas com suporte corporativo. Para cada estrutura, as formas de atuação das áreas diferem, objetivando satisfazer as premissas gerenciais ...

  8. On scalar condensate baryogenesis model

    International Nuclear Information System (INIS)

    Kiriloval, D.P.; Valchanov, T.V.

    2004-09-01

    We discuss the scalar field condensate baryogenesis model, which is among the baryogenesis scenarios preferred today, compatible with inflation. According to that model a complex scalar field φ, carrying baryon charge B≠0 is generated at inflation. The baryon excess in the Universe results from the φ decay at later stages of Universe evolution (T 15 GeV). We updated the model's parameters range according to the current observational cosmological constraints and analyzed numerically φ evolution after the inflationary stage till its decay φ → qq-barlγ. During that period oscillated with a decreasing amplitude due to Universe expansion and particle production processes due to the coupling of the field to fermions gφf 1 f 2 . It was shown that particle creation processes play an essential role for evolution and its final value. It may lead to a considerable decrease of the field's amplitude for large g and/or large H values, which reflects finally into strong damping of the baryon charge carried by the condensate. The analysis suggests that for a natural range of the model's parameters the observed value of the baryon asymmetry can be obtained and the model can serve as a successful baryogenesis model, compatible with inflation. (author)

  9. Condensation induced water hammer safety

    Energy Technology Data Exchange (ETDEWEB)

    Gintner, M.A.

    1997-03-10

    Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer.

  10. Muonic Chemistry in Condensed Matter

    CERN Multimedia

    2002-01-01

    When polarized muons (@m|+) stop in condensed matter, muonic atoms are formed in the final part of their range, and direct measurements of the @m|+-spin polarization are possible via the asymmetric decay into positrons. The hyperfine interaction determines the characteristic precession frequencies of the @m|+ spin in muonium, @w(Mu). Such frequencies can be altered by the interactions of the muonium's electron spin with the surrounding medium. The measurement of @w(Mu) in a condensed system is known often to provide unique information regarding the system. \\\\ \\\\ In particular, the use of muonium atoms as a light isotope of the simple reactive radical H|0 allows the investigation of fast reactions of radicals over a typical time scale 10|-|9~@$<$~t~@$<$~10|-|5~sec, which is determined by the instrumental resolution at one end and by the @m|+ lifetime at the other. \\\\ \\\\ In biological macromolecules transient radicals, such as the constituents of DNA itself, exist on a time scale of sub-microseconds, acco...

  11. Magnon condensation and spin superfluidity

    Science.gov (United States)

    Bunkov, Yury M.; Safonov, Vladimir L.

    2018-04-01

    We consider the Bose-Einstein condensation (BEC) of quasi-equilibrium magnons which leads to spin superfluidity, the coherent quantum transfer of magnetization in magnetic material. The critical conditions for excited magnon density in ferro- and antiferromagnets, bulk and thin films, are estimated and discussed. It was demonstrated that only the highly populated region of the spectrum is responsible for the emergence of any BEC. This finding substantially simplifies the BEC theoretical analysis and is surely to be used for simulations. It is shown that the conditions of magnon BEC in the perpendicular magnetized YIG thin film is fulfillied at small angle, when signals are treated as excited spin waves. We also predict that the magnon BEC should occur in the antiferromagnetic hematite at room temperature at much lower excited magnon density compared to that of ferromagnetic YIG. Bogoliubov's theory of Bose-Einstein condensate is generalized to the case of multi-particle interactions. The six-magnon repulsive interaction may be responsible for the BEC stability in ferro- and antiferromagnets where the four-magnon interaction is attractive.

  12. Condensation induced water hammer safety

    International Nuclear Information System (INIS)

    Gintner, M.A.

    1997-01-01

    Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer

  13. ESTRUTURA ORGANIZACIONAL E GESTÃO DO CONHECIMENTO

    Directory of Open Access Journals (Sweden)

    Edoardo Perrotti

    2005-11-01

    -style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->

    Resumo

    Determinar quais os efeitos dos critérios de departamentalização em estruturas organizacionais na geração e disseminação do conhecimento é o objetivo principal proposto nesta pesquisa. Para isto há necessidade de entender como o conhecimento e as informações circulam dentro das organizações, quais tipos de conhecimento são estes, quais processos são utilizados para disseminação dos novos conhecimentos adquiridos, como são gerados os conhecimentos nas organizações, como a empresa está estruturada, dentre outros temas relevantes para o estudo. Com os dados gerais obtidos através da aplicação das entrevistas, foi elaborada uma análise qualitativa para detecção de correlação efetiva entre questões e variáveis. O presente estudo permitiu concluir que a Estrutura Organizacional pode ter efeito substancialmente positivo sobre a Gestão do

  14. Bio-oil fractionation and condensation

    Science.gov (United States)

    Brown, Robert C; Jones, Samuel T; Pollard, Anthony

    2013-07-02

    A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

  15. The physics of exciton-polariton condensates

    CERN Document Server

    Lagoudakis, Konstantinos

    2013-01-01

    In 2006 researchers created the first polariton Bose-Einstein condensate at 19K in the solid state. Being inherently open quantum systems, polariton condensates open a window into the unpredictable world of physics beyond the “fifth state of matter”: the limited lifetime of polaritons renders polariton condensates out-of-equilibrium and provides a fertile test-bed for non-equilibrium physics. This book presents an experimental investigation into exciting features arising from this non-equilibrium behavior. Through careful experimentation, the author demonstrates the ability of polaritons to synchronize and create a single energy delocalized condensate. Under certain disorder and excitation conditions the complete opposite case of coexisting spatially overlapping condensates may be observed. The author provides the first demonstration of quantized vortices in polariton condensates and the first observation of fractional vortices with full phase and amplitude characterization. Finally, this book investigate...

  16. THE STABILITY OF VAPOR CONDENSATION EQUILIBRIUM

    OpenAIRE

    SHIMIN ZHANG

    2005-01-01

    The system must get across an energy peak of unstable equilibrium during the condensation of pure vapor; as the supersaturated extent of vapor increases and the temperature decreases, the energy peak shortens and vapor condensation becomes easier. The system must get across an energy peak of unstable equilibrium first, and then get into an energy valley of stable equilibrium during the condensation of impure vapor; as the partial pressure of vapor decreases, the energy peak becomes taller, th...

  17. Nonlinear behavior of the radiative condensation instability

    International Nuclear Information System (INIS)

    McCarthy, D.; Drake, J.F.

    1991-01-01

    An investigation of the nonlinear behavior of the radiative condensation instability is presented in a simple one-dimensional magnetized plasma. It is shown that the radiative condensation is typically a nonlinear instability---the growth of the instability is stronger once the disturbance reaches finite amplitude. Moreover, classical parallel thermal conduction is insufficient by itself to saturate the instability. Radiative collapse continues until the temperature in the high density condensation falls sufficiently to reduce the radiation rate

  18. Physics of hollow Bose-Einstein condensates

    OpenAIRE

    Padavić, Karmela; Sun, Kuei; Lannert, Courtney; Vishveshwara, Smitha

    2016-01-01

    Bose-Einstein condensate shells, while occurring in ultracold systems of coexisting phases and potentially within neutron stars, have yet to be realized in isolation on Earth due to the experimental challenge of overcoming gravitational sag. Motivated by the expected realization of hollow condensates by the space-based Cold Atomic Laboratory in microgravity conditions, we study a spherical condensate undergoing a topological change from a filled sphere to a hollow shell. We argue that the col...

  19. Advances in modelling of condensation phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.S.; Zaltsgendler, E. [Ontario Hydro Nuclear, Toronto (Canada); Hanna, B. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

    1997-07-01

    The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described.

  20. Strangeness condensation and ''clearing'' of the vacuum

    International Nuclear Information System (INIS)

    Brown, G.E.; Kubodera, Kuniharu; Rho, M.; State Univ. of New York, Stony Brook

    1987-01-01

    We show that a substantial amount of strange quark-antiquark pair condensates in the nucleon required by the πN sigma term implies that kaons could condense in nuclear matter at a density about three times that of normal nuclear matter. This phenomenon can be understood as the ''cleansing'' of qanti q condensates from the QCD vacuum by a dense nuclear matter, resulting in a (partial) restoration of the chiral symmetry explicitly broken in the vacuum. It is suggested that the condensation signals a new phase distinct from that of quark plasma and that of ordinary dense hadronic matter. (orig.)

  1. Estrutura de um fragmento florestal no Engenho Humaitá, Catende, Pernambuco, Brasil

    OpenAIRE

    Guimarães,Francisco J. P.; Ferreira,Rinaldo L. C.; Marangon,Luiz C.; Silva,José A. A. da; Aparício,Perseu da S.; Alves Júnior,Francisco T.

    2009-01-01

    Avaliou-se, neste trabalho, a estrutura de um fragmento florestal antropizado denominado Mata das Galinhas, Engenho Humaitá, Catende, Pernambuco, e se utilizaram, para avaliar a composição florística e a estrutura fitossociológica, 14 parcelas de 10 x 25 m a fim de amostrar os indivíduos arbóreos com circunferência a 1,30 m do solo (CAP) ≥ 10 cm. Foram estimados, então, densidade, frequência e dominância e valor de importância (VI) e o índice de Shannon, além de registrados 438 indivídu...

  2. Domo de Izumo: estudos integrados sobre arquitetura, estrutura e construção

    Directory of Open Access Journals (Sweden)

    Marta Etsuko Tamura Waragaya

    2008-06-01

    Full Text Available O presente trabalho traz uma análise crítica sobre o domo de Izumo e suas relações intrínsecas entre arquitetura, estrutura e sistema construtivo, verificando-se que as soluções adotadas refletem a interdisciplinaridade existente nessa obra, a qual alia conceitos de arquitetura de grandes vãos; estrutura mista em madeira laminada, conexões metálicas e construção racionalizada em push-up. Verifica também as características do espaço construído, comportamento do sistema estrutural e operações construtivas do domo de Izumo por meio do modelo físico e comparação gráfica.

  3. Erosões nas estruturas de concreto das galerias de aguas pluviais urbanas

    OpenAIRE

    Aguiar,J. E. de; Baptista,M. B.

    2011-01-01

    Este trabalho apresenta as conseqüências do surgimento das erosões no interior das estruturas de concreto das galerias de águas pluviais urbanas, com base em inspeções feita em mais de 180 km na rede de drenagem da cidade de Belo Horizonte (Brasil). O artigo descreve a gênese das erosões que po­dem ser por abrasão, por cavitação e por ataque químico, mostrando os processos de formação e evolução das patologias, chamando a atenção que elas podem levar as estruturas ao colapso. São apresentados...

  4. Proteção catódica de estruturas de concreto

    OpenAIRE

    Araujo,A.; Panossian,Z.; Lourenço,Z.

    2013-01-01

    A adoção de técnicas de proteção às estruturas do concreto é recomendada quando há preocupação com a corrosão das armaduras de aço-carbono. Dentre as principais técnicas, destaque-se a proteção catódica que pode tanto evitar a corrosão prematura como diminuir um processo corrosivo em curso. No exterior, a técnica de proteção catódica tem sido aplicada em vários tipos de estruturas de concreto, especialmente nas sujeitas à corrosão pelo ataque de íons cloreto. No Brasil, essa técnica é pouco u...

  5. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: NEW CONDENSATOR, INC.--THE CONDENSATOR DIESEL ENGINE RETROFIT CRANKCASE VENTILATION SYSTEM

    Science.gov (United States)

    EPA's Environmental Technology Verification Program has tested New Condensator Inc.'s Condensator Diesel Engine Retrofit Crankcase Ventilation System. Brake specific fuel consumption (BSFC), the ratio of engine fuel consumption to the engine power output, was evaluated for engine...

  6. Proteção catódica de estruturas de concreto

    Directory of Open Access Journals (Sweden)

    A. Araujo

    Full Text Available A adoção de técnicas de proteção às estruturas do concreto é recomendada quando há preocupação com a corrosão das armaduras de aço-carbono. Dentre as principais técnicas, destaque-se a proteção catódica que pode tanto evitar a corrosão prematura como diminuir um processo corrosivo em curso. No exterior, a técnica de proteção catódica tem sido aplicada em vários tipos de estruturas de concreto, especialmente nas sujeitas à corrosão pelo ataque de íons cloreto. No Brasil, essa técnica é pouco usada em estruturas de concreto, o que decorre, em parte, do desconhecimento sobre o seu princípio de funcionamento e da ausência de sistemas disponíveis para aplicação ao concreto (armado ou protendido. O objetivo deste trabalho é apresentar o princípio da proteção catódica para estruturas com armaduras de aço-carbono novas ou já em processo de corrosão. Os métodos de proteção catódica por corrente impressa e por anodo de sacrifício são discutidos. Um caso prático com uso de proteção catódica por corrente impressa, também, é apresentado.

  7. Mudança de estrutura moraica do latim ao português

    Directory of Open Access Journals (Sweden)

    Evellyne Patrícia Figueiredo de Sousa Costa

    2011-12-01

    Full Text Available Este estudo tem como objetivo investigar a evolução da estrutura moraica do latim ao português. A língua latina apresenta distinção quantitativa vocálica e consonantal: (i sílabas leves, portadoras de uma mora (e.le.men.tum; (ii sílabas pesadas, portadoras de duas moras (bul.ga; (iii sílabas superpesadas, portadoras de três moras segundo a nossa proposta (paul.lum. Diacronicamente, há a perda da distintividade quantitativa dentre as vogais e, na passagem às línguas neorromânicas, a estrutura moraica tem seus efeitos. Diante desse cenário e a partir dos pressupostos da Teoria Moraica de Hayes (1989, investigamos os efeitos dessa mudança através de processos fonológicos envolvidos, tais como ditongação e monotongação. A Teoria Moraica busca caracterizar de que modo as línguas atribuem estrutura moraica e que princípios atuam nessas línguas. Hayes (1989 define mora como uma unidade de peso do tier prosódico que caracteriza o contraste entre sílabas longas e breves, além de contar como uma posição fonológica (segmento longo é representado como duplamente ligado. Propomos que as escolhas feitas pela língua portuguesa, tais como ditongação e monotongação, para lidar com a estrutura moraica latina já estão disponíveis em latim vulgar e que princípios como Stray Erasure e Parasitic Delinking, relacionados com Licenciamento Prosódico atuam na referida mudança.

  8. Um estudo da estrutura organizacional e as mudanças organizacionais: proposta de um novo modelo

    Directory of Open Access Journals (Sweden)

    Maria Clara Fraga da Costa

    2012-03-01

    Full Text Available O estudo apresenta como objetivo a proposição de novo modelo de estrutura organizacional, frente às mudanças impostas pela atualidade. A partir de pesquisa bibliográfica sistematizada, evidenciou-se a evolução das estruturas organizacionais dentro da literatura existente sobre o tema. A nova proposta foi denominada estrutura organizacional por conjunto e utiliza a base gráfica de união de conjuntos matemáticos e teóricos sobre a estrutura organizacional de hipertexto.  Ela está fundamentada na ideia de adequação às mudanças e exigência de sustentabilidade das empresas, levando em consideração a possibilidade de crescimento dentro de um ambiente turbulento.

  9. Provisão pública e privada da infra-estrutura e desenvolvimento econômico

    Directory of Open Access Journals (Sweden)

    Andrew B. Bernard

    2013-12-01

    Full Text Available Este artigo faz um levantamento da literatura em infra-estrutura e desenvolvimento econômico e discute vários exemplos de provisão de infra-estrutura pelo setor privado. A primeira parte do artigo apresenta uma discussão teórica sobre a função dos gastos públicos com investimento no crescimento econômico de longo prazo. A segunda parte discute alguns dos trabalhos empíricos que verificam a existência de uma relação positiva entre níveis de infra-estrutura e taxas de crescimento. A parte final apresenta diversos exemplos de parceria público-privada em projetos de infra-estrutura no mundo.

  10. Um estudo da estrutura organizacional e as mudanças organizacionais: proposta de um novo modelo

    Directory of Open Access Journals (Sweden)

    Maria Clara Fraga da Costa

    2012-03-01

    Full Text Available O estudo apresenta como objetivo a proposição de novo modelo de estrutura organizacional, frente às mudanças impostas pela atualidade. A partir de pesquisa bibliográfica sistematizada, evidenciou-se a evolução das estruturas organizacionais dentro da literatura existente sobre o tema. A nova proposta foi denominada estrutura organizacional por conjunto e utiliza a base gráfica de união de conjuntos matemáticos e teóricos sobre a estrutura organizacional de hipertexto. Ela está fundamentada na ideia de adequação às mudanças e exigência de sustentabilidade das empresas, levando em consideração a possibilidade de crescimento dentro de um ambiente turbulento.

  11. Verificação da resistência de estruturas de aço ao fogo

    OpenAIRE

    Mesquita, Alex

    2013-01-01

    Dissertação para obtenção do Grau de Mestre em Engenharia Civil – Ramo de estruturas Esta dissertação tem como objetivo a análise e dimensionamento de estruturas de aço ao fogo segundo o Eurocódigo 3, dando maior ênfase à parte 1-2 que diz respeito a estruturas de aço em situação de incêndio. As estruturas de aço são amplamente utilizadas na construção de edifícios devido à sua elevada resistência mecânica, boa ductilidade e rápida execução da obra. No entanto, devido à deterioração ...

  12. Quasiparticles in condensed matter systems

    Science.gov (United States)

    Wölfle, Peter

    2018-03-01

    Quasiparticles are a powerful concept of condensed matter quantum theory. In this review, the appearence and the properties of quasiparticles are presented in a unifying perspective. The principles behind the existence of quasiparticle excitations in both quantum disordered and ordered phases of fermionic and bosonic systems are discussed. The lifetime of quasiparticles is considered in particular near a continuous classical or quantum phase transition, when the nature of quasiparticles on both sides of a transition into an ordered state changes. A new concept of critical quasiparticles near a quantum critical point is introduced, and applied to quantum phase transitions in heavy fermion metals. Fractional quasiparticles in systems of restricted dimensionality are reviewed. Dirac quasiparticles emerging in so-called Dirac materials are discussed. The more recent discoveries of topologically protected chiral quasiparticles in topological matter and Majorana quasiparticles in topological superconductors are briefly reviewed.

  13. Investimentos em infra-estrutura e produtividade total dos fatores na agricultura brasileira: 1985-2004

    Directory of Open Access Journals (Sweden)

    Sérgio Magno Mendes

    2009-06-01

    Full Text Available Investimentos em infra-estrutura no Brasil reduziram-se significativamente desde a década de 1980, possivelmente comprometendo a Produtividade Total dos Fatores (PTF e a competitividade da agropecuária. Uma adaptação do modelo de Zhang and Fan (2004 para a Índia, utilizando-se o Método Generalizado de Momentos, foi aplicada para verificar os efeitos dos investimentos em infra-estrutura na PTF. Estimou-se que esses investimentos afetam a PTF logo nos primeiros anos, com retorno ocorrendo de 0 a 2 anos. Dos elementos de infra-estrutura analisados, investimentos em rodovia tiveram o maior impacto na PTF, seguidos por investimento em pesquisa, telecomunicações, irrigação e energia elétrica.Infrastructure investments in Brazil were reduced significantly since the decade of 1980, possibly compromising Total Factor Productivity (TFP and agricultural competitivity. In this paper, Solow's growth model with panel data is used to estimate TFP. An adaptation of the model of Zhang and Fan (2004 for India, using the Generalized Method of Moments, was applied to find effect of infrastructure investments on TFP. Estimations suggest that these investments affect agriculture TFP in the first years and its return occurs in the period of 0 to 2 years. Road investments have the highest impact on TFP, followed by investments on research, telecommunications, irrigation, and electric energy.

  14. Possibility of removing condensate and scattered oil from gas-condensate field during bed flooding

    Energy Technology Data Exchange (ETDEWEB)

    Belkina, N.A.; Yagubov, M.S.

    1984-01-01

    The problem is set of evaluating the possible removal from the bed of scattered oil and condensate during flooding of the bed. For this purpose, an experimental study was made of the displacement by water from the porous medium of the oil and condensate saturating it. The obtained experimental results permit evaluation of the possible removal from the gas-condensate bed of scattered oil and condensate during flooding of the bed.

  15. Statistical physics and condensed matter

    International Nuclear Information System (INIS)

    2003-01-01

    This document is divided into 4 sections: 1) General aspects of statistical physics. The themes include: possible geometrical structures of thermodynamics, the thermodynamical foundation of quantum measurement, transport phenomena (kinetic theory, hydrodynamics and turbulence) and out of equilibrium systems (stochastic dynamics and turbulence). The techniques involved here are typical of applied analysis: stability criteria, mode decomposition, shocks and stochastic equations. 2) Disordered, glassy and granular systems: statics and dynamics. The complexity of the systems can be studied through the structure of their phase space. The geometry of this phase space is studied in several works: the overlap distribution can now be computed with a very high precision; the boundary energy between low lying states does not behave like in ordinary systems; and the Edward's hypothesis of equi-probability of low lying metastable states is invalidated. The phenomenon of aging, characteristic of glassy dynamics, is studied in several models. Dynamics of biological systems or of fracture is shown to bear some resemblance with that of disordered systems. 3) Quantum systems. The themes include: mesoscopic superconductors, supersymmetric approach to strongly correlated electrons, quantum criticality and heavy fermion compounds, optical sum rule violation in the cuprates, heat capacity of lattice spin models from high-temperature series expansion, Lieb-Schultz-Mattis theorem in dimension larger than one, quantum Hall effect, Bose-Einstein condensation and multiple-spin exchange model on the triangular lattice. 4) Soft condensed matter and biological systems. Path integral representations are invaluable to describe polymers, proteins and self-avoiding membranes. Using these methods, problems as diverse as the titration of a weak poly-acid by a strong base, the denaturation transition of DNA or bridge-hopping in conducting polymers have been addressed. The problems of RNA folding has

  16. Physical-chemical properties of the surface of B2O3-P2O5-MeOx/SiO2 catalysts and its effect on the parameters of the process of aldol condensation of propionic acid with formaldehyde

    International Nuclear Information System (INIS)

    Yivasyiv, V.V.; Pyikh, Z.G.; Zhiznevs'kij, V.M.; Nebesnij, R.V.

    2011-01-01

    Effect of catalyst B 2 O 3 -P 2 O 5 -MeO x /SiO 2 composition on its physical-chemical properties has been investigated. Relations between physical-chemical and catalytic properties of catalysts in the gas-phase reaction of propionic acid with formaldehyde to methacrylic acid have been found. Effect of the specific surface area and the specific surface acidity on the propionic acid conversion has been determined. Effect of the acidic active site's strength on the selectivity of reaction products has been determined. It has been pointed that methacrylic acid is formed on the moderate strength acidic active sites, whereas the by-product (diethyl ketone) - on the strong acidic active sites of the catalyst.

  17. Connections between quantum chromodynamics and condensed ...

    Indian Academy of Sciences (India)

    Abstract. Features of QCD can be seen qualitatively in certain condensed matter systems. Recently some of the analyses that originated in condensed matter physics have found applications in QCD. Using examples we discuss some of the connections between the two fields and show how progress can be made by ...

  18. Condensate growth in trapped Bose gates

    NARCIS (Netherlands)

    Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

    2000-01-01

    We study the dynamics of condensate fromation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field efects in the condensed and the noncondensed parts of the gas.

  19. Condensate growth in trapped Bose gases

    NARCIS (Netherlands)

    Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

    2000-01-01

    We study the dynamics of condensate formation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field effects in the condensed and the noncondensed parts of the gas.

  20. Tunneling of trapped-atom Bose condensates

    Indian Academy of Sciences (India)

    Tunneling of trapped-atom Bose condensates. SUBODH R SHENOY. Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, Trieste 34100, Italy. Abstract. We obtain the dynamics in number and phase difference, for Bose condensates that tun- nel between two wells of a double-well atomic trap, using the ...

  1. Collision of Bose Condensate Dark Matter structures

    International Nuclear Information System (INIS)

    Guzman, F. S.

    2008-01-01

    The status of the scalar field or Bose condensate dark matter model is presented. Results about the solitonic behavior in collision of structures is presented as a possible explanation to the recent-possibly-solitonic behavior in the bullet cluster merger. Some estimates about the possibility to simulate the bullet cluster under the Bose Condensate dark matter model are indicated.

  2. Soliton resonance in bose-einstein condensate

    Science.gov (United States)

    Zak, Michail; Kulikov, I.

    2002-01-01

    A new phenomenon in nonlinear dispersive systems, including a Bose-Einstein Condensate (BEC), has been described. It is based upon a resonance between an externally induced soliton and 'eigen-solitons' of the homogeneous cubic Schrodinger equation. There have been shown that a moving source of positive /negative potential induces bright /dark solitons in an attractive / repulsive Bose condensate.

  3. Effective thermal conductivity of condensed polymeric nanofluids ...

    Indian Academy of Sciences (India)

    Thermal properties of polymeric nanosolids, obtained by condensing the corresponding nanofluids, are investigated using photothermal techniques. The heat transport properties of two sets of polyvinyl alcohol (PVA) based nanosolids, TiO2/PVA and Cu/PVA, prepared by condensing the respective nanofluids, which are ...

  4. Quantum monodromy in trapped Bose condensates

    NARCIS (Netherlands)

    Waalkens, H.

    2002-01-01

    Bose-Einstein condensation of ultra cold atoms is typically realized in magnetic traps which effectively lead to an axially symmetric harmonic potential. This letter shows that the spectrum of collective vibrational modes of a repulsive condensate in a prolate potential displays a defect known as

  5. Born-Kothari Condensation for Fermions

    Directory of Open Access Journals (Sweden)

    Arnab Ghosh

    2017-09-01

    Full Text Available In the spirit of Bose–Einstein condensation, we present a detailed account of the statistical description of the condensation phenomena for a Fermi–Dirac gas following the works of Born and Kothari. For bosons, while the condensed phase below a certain critical temperature, permits macroscopic occupation at the lowest energy single particle state, for fermions, due to Pauli exclusion principle, the condensed phase occurs only in the form of a single occupancy dense modes at the highest energy state. In spite of these rudimentary differences, our recent findings [Ghosh and Ray, 2017] identify the foregoing phenomenon as condensation-like coherence among fermions in an analogous way to Bose–Einstein condensate which is collectively described by a coherent matter wave. To reach the above conclusion, we employ the close relationship between the statistical methods of bosonic and fermionic fields pioneered by Cahill and Glauber. In addition to our previous results, we described in this mini-review that the highest momentum (energy for individual fermions, prerequisite for the condensation process, can be specified in terms of the natural length and energy scales of the problem. The existence of such condensed phases, which are of obvious significance in the context of elementary particles, have also been scrutinized.

  6. Dropwise Condensation Enhancement on Geometric Features

    Science.gov (United States)

    Zhao, Yajing; Preston, Daniel J.; Lu, Zhengmao; Wang, Evelyn N.

    Dropwise condensation, which has been demonstrated to exhibit a 5-7X higher heat transfer coefficient compared with state-of-the-art filmwise condensation, contributes to energy savings in a wide range of applications such as desalination systems, steam cycles and dew harvesting. In order to enhance dropwise condensation performance, previous studies have investigated the effects of surface geometric features on droplet growth rates and found that bumps protruding from surfaces can effectively promote dropwise condensation. In this work, we show that while bumps on surfaces enable droplets to grow faster in some cases, there are also cases where bumps on surfaces actually degrade dropwise condensation. We numerically simulated and experimentally demonstrated that even the same surface geometric feature can exert completely opposite effects on dropwise condensation of water under two different working conditions (pure vapor vs. air vapor mixture). This phenomenon is explained by comparing the heat and mass transfer resistance of the surface structure to that of the vapor transport during dropwise condensation. We expect that the fundamental understanding developed in this study will provide useful guidelines for relevant condensation applications.

  7. Assessment of the controllability of condensible emissions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Shareef, G.S.; Waddell, J.T.

    1990-10-01

    The report gives results of a study to gain insights into the condensible emissions area from an air toxics perspective, with emphasis on controllability and chemical composition of these emissions. The study: compiled existing data on condensible emissions; determined the chemical composition of condensible emissions, where possible; identified source categories that are major emitters of condensibles; evaluated the effectiveness of various control devices in reducing condensible emissions; and evaluated how the performance of currently available control technologies can be improved to better control condensible emissions. Two data bases were developed: the Condensibles Data Base contains 43 emission source categories; the Specialized Condensibles Data Base focuses on the chemical composition of condensible emissions.

  8. Capillary Condensation in 8 nm Deep Channels.

    Science.gov (United States)

    Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David

    2018-02-01

    Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.

  9. Effects of Composition and Structure of Mg/Al Oxides on Their Activity and Selectivity for the Condensation of Methyl Ketones

    KAUST Repository

    Shylesh, Sankaranarayanapillai

    2016-09-22

    The effects of chemical composition and pretreatment on Mg–Al hydrotalcites and alumina-supported MgO were evaluated for the gas-phase, self-condensation reaction of C3–C5 biomass-derived methyl ketones. We show that the selectivity toward the acyclic dimer enone and the cyclic enone trimer can be tuned by controlling the temperature of hydrotalcite calcination. Methyl ketone cyclization is promoted by Lewis acidic sites present on the hydrotalcite catalysts. XRD and thermal decomposition analysis reveal that the formation of periclase MgO starts above 623 K accompanied by complete disappearance of the hydrotalcite structure and is accompanied by an increase in hydroxyl condensation as the formation of well-crystallized periclase. 27Al MQMAS and 25Mg MAS NMR show that at progressively higher temperatures, Al3+ cations diffuses out of the octahedral brucite layers and incorporate into the tetrahedral and octahedral sites of the MgO matrix thereby creating defects to compensate the excess positive charge generated. The oxygen anions adjacent to the Mg2+/Al3+ defects become coordinatively unsaturated, leading to the formation of new basic sites. A kinetic isotope effect, kH/kD = 0.96, is observed at 473 K for the reaction of (CH3)2CO versus (CD3)2CO, which suggests that carbon–carbon bond formation leading to the dimer aldol product is the rate-determining step in the condensation reaction of methyl ketones. We also show that acid–base catalysts having similar reactivity and higher hydrothermal stability to that of calcined hydrotalcites can be achieved by creating defects in MgO crystallites supported alumina as a consequence of the diffusion of Al3+ cations into MgO. The physical properties of these materials are shown to be very similar to those of hydrotalcite calcined at 823 K.

  10. A new synthesis of enantiomerically pure syn-(S)-β-hydroxy-α-amino acids via asymmetric aldol reactions of aldehydes with a homochiral Ni(II)-glycine/(S)-BPB Schiff base complex

    OpenAIRE

    Belokon, Yuri N.; Kochetkov, Konstantin A.; Ikonnikov, Nikolai S.; Strelkova, Tatiana V.; Harutyunyan, Syuzanna R.; Saghiyan, Ashot S.

    2001-01-01

    syn-(S)-β-Hydroxy-α-amino acids were synthesised stereoselectively via elaboration of the asymmetric aldol reactions of aldehydes with a chiral Ni(II)-(S)-BPB/glycine Schiff base complex in the presence of equimolar NaH in THF. The stereoselectivity of the reaction was studied as a function of time, the reaction conditions, the nature of the carbonyl compounds and the base used. The synthetic potential of this asymmetric method was demonstrated in the preparation of syn-(S)-β-hydroxyleucine o...

  11. Curiosidades sobre a reação aldólica utilizada como etapa chave na síntese Brasileira dos ácidos pterídicos A e B Curiosities about the aldol reaction employed as a key step in the synthesis of pteridic acids A and B

    Directory of Open Access Journals (Sweden)

    Luiz C. Dias

    2010-01-01

    Full Text Available This work describes an overview of our synthesis of pteridic acids A and B and discloses some interesting results related to the lithium enolate-mediated aldol reaction used as key step to set up the C5-C15 fragment of these natural products. This first example, as far we know, of an aldol reaction between a chiral enolate of a (Z enone and a chiral aldehyde has driven us to a series of experiments showing the remarkable relation between enolization selectivity and reaction conditions.

  12. Condensing boiler applications in the process industry

    International Nuclear Information System (INIS)

    Chen, Qun; Finney, Karen; Li, Hanning; Zhang, Xiaohui; Zhou, Jue; Sharifi, Vida; Swithenbank, Jim

    2012-01-01

    Major challenging issues such as climate change, energy prices and fuel security have focussed the attention of process industries on their energy efficiency and opportunities for improvement. The main objective of this research study was to investigate technologies needed to exploit the large amount of low grade heat available from a flue gas condensing system through industrial condensing boilers. The technology and application of industrial condensing boilers in various heating systems were extensively reviewed. As the condensers require site-specific engineering design, a case study was carried out to investigate the feasibility (technically and economically) of applying condensing boilers in a large scale district heating system (40 MW). The study showed that by recovering the latent heat of water vapour in the flue gas through condensing boilers, the whole heating system could achieve significantly higher efficiency levels than conventional boilers. In addition to waste heat recovery, condensing boilers can also be optimised for emission abatement, especially for particle removal. Two technical barriers for the condensing boiler application are corrosion and return water temperatures. Highly corrosion-resistant material is required for condensing boiler manufacture. The thermal design of a 'case study' single pass shell-and-tube condensing heat exchanger/condenser showed that a considerable amount of thermal resistance was on the shell-side. Based on the case study calculations, approximately 4900 m 2 of total heat transfer area was required, if stainless steel was used as a construction material. If the heat transfer area was made of carbon steel, then polypropylene could be used as the corrosion-resistant coating material outside the tubes. The addition of polypropylene coating increased the tube wall thermal resistance, hence the required heat transfer area was approximately 5800 m 2 . Net Present Value (NPV) calculations showed that the choice of a carbon

  13. Condensing embryology teaching: alternative perspectives

    Directory of Open Access Journals (Sweden)

    Hasan M

    2018-03-01

    Full Text Available Mohammad Hasan, Syed Maaz Tariq, Syed Ali Haider Department of MBBS, Jinnah Sindh Medical University, Karachi, PakistanWe read the article “Condensing embryology teaching for medical students: can it be taught in 2 hours?” by Kazzazi and Bartlett quite attentively. The authors were successful in mentioning an effective mode of teaching embryology. Embryology is indeed an important subject that forms the base for appreciating anatomy and has immense practical implementations in different parts of medicine, for example, in pediatrics and ENT surgery. However, it is often neglected and is only taught in preclinical years.1 The authors proposed a method for teaching embryology splendidly from their perspective; therefore, we felt the need to expand the discussion from the perspective of third-year medical students who have just completed their preclinical years. Hence, we would like to mention few limitations to this study as well.Authors’ replyFawz Kazzazi, Jonathan Bartlett School of Clinical Medicine, University of Cambridge, Cambridge, UKWe read with interest the response letter by Hasan et al. We must first commend the editor and journal on their great ability to unify the medical community and extend topics for debate internationally.View the original paper by Kazzazi and Bartlett.

  14. Topology and condensed matter physics

    CERN Document Server

    Mj, Mahan; Bandyopadhyay, Abhijit

    2017-01-01

    This book introduces aspects of topology and applications to problems in condensed matter physics. Basic topics in mathematics have been introduced in a form accessible to physicists, and the use of topology in quantum, statistical and solid state physics has been developed with an emphasis on pedagogy. The aim is to bridge the language barrier between physics and mathematics, as well as the different specializations in physics. Pitched at the level of a graduate student of physics, this book does not assume any additional knowledge of mathematics or physics. It is therefore suited for advanced postgraduate students as well. A collection of selected problems will help the reader learn the topics on one's own, and the broad range of topics covered will make the text a valuable resource for practising researchers in the field.  The book consists of two parts: one corresponds to developing the necessary mathematics and the other discusses applications to physical problems. The section on mathematics is a qui...

  15. Ice-condenser aerosol tests

    International Nuclear Information System (INIS)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K.

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m 3 /s resulted in stable thermal stratification whereas flows less than 0.1 m 3 /s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs

  16. Ice-condenser aerosol tests

    Energy Technology Data Exchange (ETDEWEB)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K. (Pacific Northwest Lab., Richland, WA (United States))

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between {approximately}0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m{sup 3}/s resulted in stable thermal stratification whereas flows less than 0.1 m{sup 3}/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs.

  17. Direct contact condensation in packed beds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-12-15

    A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

  18. Emergency condensator for BWR type reactor

    International Nuclear Information System (INIS)

    Ubakai, Yoichi; Narumi, Yuichi; Sakata, Yuji.

    1992-01-01

    An emergency condensator is constituted with heat transfer pipes, a steam chamber, an upper pipe plate, a lower pipe plate and a condensate chamber. The upper pipe plate is secured by supports, and a steam pipe is connected to the upper pipe plate. A condensate pipeline and a incondensible gas vent pipe are disposed to the condensate chamber. Taking thermal expansion of the steam pipes and thermal expansion of the heat transfer pipes into consideration, the heat transfer pipe is made as an L-shaped pipe having a vertical portion and a horizontal portion so as to absorb each of the thermal expansion smoothly. The L-shaped heat transfer pipes are constituted as a bundle of pipes having the end portions thereof secured to the upper pipe plate and the lower pipe plate. The emergency condensator is disposed in a emergency condensator pool chamber. Cooling water in contact with the outer side of the L-shaped heat transfer pipes is the pool water in the pool chamber, and the condensator chamber is disposed in concrete walls of the pool chamber. With such a constitution, stress due to thermal expansion of the heat transfer pipes is mitigated, and heat transfer performance, earth quake resistance and maintenancability are improved. (I.N.)

  19. Low-temperature Condensation of Carbon

    Science.gov (United States)

    Krasnokutski, S. A.; Goulart, M.; Gordon, E. B.; Ritsch, A.; Jäger, C.; Rastogi, M.; Salvenmoser, W.; Henning, Th.; Scheier, P.

    2017-10-01

    Two different types of experiments were performed. In the first experiment, we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium, while in the second experiment, we studied the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high temperatures, supposedly higher than 1000°C, during condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperature condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers. Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via the addition of carbon atoms to H2 and CO molecules ({{C}}+{{{H}}}2\\to {HCH},{HCH}+{CO}\\to {{OCCH}}2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.

  20. Active condensation of water by plants

    Directory of Open Access Journals (Sweden)

    Prokhorov Alexey Anatolievich

    2013-10-01

    Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.

  1. Quark virtuality and QCD vacuum condensates

    International Nuclear Information System (INIS)

    Zhou Lijuan; Ma Weixing

    2004-01-01

    Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions

  2. Open string decoupling and tachyon condensation

    International Nuclear Information System (INIS)

    Chalmers, G.

    2001-01-01

    The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants g s and g YM at general values of the tachyon condensate. The closed sector is generated at the quantum level; it is also generated at the classical level through the condensation of the propagating open string modes on the D-brane degrees of freedom.

  3. Preoperational test report, primary ventilation condensate system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-01-29

    Preoperational test report for Primary Ventilation Condensate System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides a collection point for condensate generated by the W-030 primary vent offgas cooling system serving tanks AYIOI, AY102, AZIOI, AZI02. The system is located inside a shielded ventilation equipment cell and consists of a condensate seal pot, sampling features, a drain line to existing Catch Tank 241-AZ-151, and a cell sump jet pump. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  4. The Dynamics of Aerosols in Condensational Scrubbers

    DEFF Research Database (Denmark)

    Johannessen, Jens Tue; Christensen, Jan A.; Simonsen, Ole

    1997-01-01

    A mathematical model for the simulation of the dynamics of aerosol change in condensational scrubbers and scrubbing condensers is proposed. The model is applicable for packed column gas/liquid contact when plug flow can be assumed. The model is compared with experimental data for particle removal...... in a pilot plant condensational scrubber. The model can satisfactorily predict particle growth and particle deposition by diffusional, convective and inertial mechanisms for a wide range of conditions. The parameters of principal importance for the model precision are identified and a procedure...

  5. Model of a chromomagnetic condensate in QCD

    International Nuclear Information System (INIS)

    Vladimirsky, V.V.

    1996-01-01

    The simplest form of the effective Lagrangian of a gluon field leads to a deep degeneracy of a magnetic condensate that arises when the stability of the standard perturbative vacuum is violated by quantum effects. The inclusion of terms in the effective Lagrangian that conserve color and Lorentz invariance enables the possible types of Abelian and non-Abelian condensate fields to be classified. The degeneracy is partially removed. One of the four types of the condensate permits the emergence of closed vortex lines that correspond to cyclic permutations of colors upon circumventions around stringlike singularities

  6. Bimodal condensation silicone elastomers as dielectric elastomers

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

    unimodal refers to that there is one polymer only in the system. As an alternative to unimodal networks there are the bimodal networks where two polymers with significantly different molecular weights are mixed with one crosslinker. [2]Silicone rubber can be divided into condensation type and addition type...... according to the curing reaction. The advantages of condensation silicones compared to addition are the relatively low cost, the curing rate largely being independent of temperature, the excellent adhesion, and the catalyst being nontoxic. [3]In this work, a series of bimodal condensation silicone...

  7. ESTRUTURA DO SOLO SOB FEIJÃO IRRIGADO E DIFERENTES MANEJO DO SOLO

    Directory of Open Access Journals (Sweden)

    Lorena Adriana de Gennaro

    2015-04-01

    Full Text Available O manejo agrícola influencia a estrutura do solo, modificando os atributos físicos e o comportamento hídrico do solo. O objetivo deste trabalho foi avaliar os efeitos da semeadura direta (SD e do preparo convencional (PC sobre a estrutura do solo, por meio de atributos físicos e da distribuição dos poros, utilizando imagens digitais 2-D. O estudo foi realizado em um Latossolo Vermelho distroférrico com delineamento de blocos casualizados. A densidade do solo, macroporosidade, diâmetro médio ponderado (DMP, condutividade hidráulica do solo saturado (Kfs e análise de imagens digitais 2-D (resolução de 156,25 μm2 foram avaliadas nas profundidades de 0-0,20 e 0,20-0,40 m. Os manejos não diferiram para a densidade e macroporosidade do solo. A SD revelou maior DMP e Kfs em relação ao PC. O PC apresentou maior área total de poros na profundidade de 0-0,20 m em relação ao SD, ocorrendo o inverso na profundidade de 0,20-0,40 m. A SD apresentou maior quantidade de poros complexos de tamanho grande (>0,156 mm2 na camada de 0,20-0,40 m em relação ao PC, que evidenciou predomínio de poros arredondados. A SD demonstrou melhorias na estrutura do solo em relação ao PC, com maior estabilidade dos agregados, condutividade hidráulica e área total de poros, contribuindo para a conservação do solo e da água em sistemas produtivos.

  8. Holography, Gravity and Condensed Matter

    Energy Technology Data Exchange (ETDEWEB)

    Hartnoll, Sean [Stanford Univ., CA (United States). Dept. of Physics

    2017-12-20

    Over the five years of funding from this grant, I produced 26 publications. These include a book-long monograph on "Holographic Quantum Matter" that is currently in press with MIT press. The remainder were mostly published in Physical Review Letters, the Journal of High Energy Physics, Nature Physics, Classical and Quantum Gravity and Physical Review B. Over this period, the field of holography applied to condensed matter physics developed from a promising theoretical approach to a mature conceptual and practical edifice, whose ideas were realized in experiments. My own work played a central role in this development. In particular, in the final year of this grant, I co-authored two experimental papers in which ideas that I had developed in earlier years were shown to usefully describe transport in strongly correlated materials — these papers were published in Science and in the Proceedings of the National Academy of Sciences (obviously my contribution to these papers was theoretical). My theoretical work in this period developed several new directions of research that have proven to be influential. These include (i) The construction of highly inhomogeneous black hole event horizons, realizing disordered fixed points and describing new regimes of classical gravity, (ii) The conjecture of a bound on diffusivities that could underpin transport in strongly interacting media — an idea which may be proven in the near future and has turned out to be intimately connected to studies of quantum chaos in black holes and strongly correlated media, (iii) The characterization of new forms of hydrodynamic transport, e.g. with phase-disordered order parameters. These studies pertain to key open questions in our understanding of how non-quasiparticle, intrinsically strongly interacting systems can behave. In addition to the interface between holography and strongly interacting condensed matter systems, I made several advances on understanding the role of entanglement in quantum

  9. Efficient, Long-Life Biocidal Condenser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity. Condensing surfaces must be...

  10. Conectores inovadores de elevado desempenho para estruturas mistas aço-betão

    OpenAIRE

    Duarte, Gonçalo Santos

    2015-01-01

    Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra A presente dissertação de Mestrado Integrado apresenta um estudo sobre conectores inovadores de elevado desempenho para estruturas mistas aço-betão. Esta tese tem forte ênfase em ensaios laboratoriais, tendo sido efectuados 8 ensaios push-out no Departamento de Engenharia Civil da Universidade de Coimbra, respeitando as especificações indicadas no Eu...

  11. Estudo do estabelecimento de configurações em estruturas celulares

    OpenAIRE

    Verônica Albers Grieneisen

    2004-01-01

    Esta dissertação investiga os processos que levam células a se organizarem em certas configurações, focando propriedades topológicas, geométricas e aquelas originadas na sua dinâmica. Para tanto, começamos revisando propriedades de topologia de equilíbrio de sistemas que minimizam áreas de contato entre células. Prosseguimos com o estudo de estruturas de células biológicas, incorporando as devidas modificações provenientes das propriedades biológicas, sendo introduzida, por exemplo, a Hipótes...

  12. A ictiofauna da ria de Aveiro: estrutura, dinâmica e populações

    OpenAIRE

    Pombo, Lúcia Maria Teixeira

    1998-01-01

    O objectivo global deste trabalho consistiu em estudar aspectos da estrutura e dinâmica da ictiofauna da Ria de Aveiro, sistema lagunar estuarino com 43 km2 de extensão, em baixa-mar, que sofre influências dulçaquícolas e marinhas e fica situado entre 40º 30’-40º52’N and 8º35’-8º47W no litoral da costa Portuguesa. A ictiofauna foi capturada mensalmente, de Dezembro de 1996 a Novembro de 1997, em nove estações de amostragem dispersas pela laguna, com uma rede de pesca tradici...

  13. Estrutura e significado em "Uma rosa para Emily", de William Faulkner

    OpenAIRE

    Daghlian,Carlos

    2004-01-01

    Trata-se de uma análise do consagrado conto "Uma Rosa para Emily", de William Faulkner, voltada para alguns dos principais aspectos de sua estrutura. Após considerarmos o enredo, discutimos a construção das personagens, com destaque para a protagonista, fazendo um levantamento e comentários sobre possíveis fontes de inspiração, destacando, entre outras, aspectos da biografia da poeta Emily Dickinson, a ficção e a poesia de E. A. Poe, romances de Charles Dickens e Henry James, o conto de Sherw...

  14. O micropoder no processo de trabalho dentro da estrutura hospitalar: vivenciando uma história

    Directory of Open Access Journals (Sweden)

    Elisabeta Albertina Nietsche

    1996-09-01

    Full Text Available Este artigo procura retratar, através de uma história, as relações de micropoderes que perpassam pelo processo de trabalho de alguns profissionais dentro dos serviços de um hospital. A base teórica que sustenta a interpretação da história está nos estudos de Foucault e autores que interpretam seus escritos. São trabalhados os seguintes micropoderes: da Instituição-Estrutura Hospitalar, da Informação e sobre o Corpo.

  15. A paradiplomacia financeira em países emergentes de estrutura federativa

    OpenAIRE

    Maia, José Nelson Bessa; Saraiva, José Flávio Sombra

    2016-01-01

    O presente artigo objetiva elaborar uma análise de política comparada por meio do mapeamento da experiência de paradiplomacia financeira em alguns países emergentes. O trabalho expõe o conceito de paradiplomacia financeira; esboça o modelo da paradiplomacia financeira em países de estrutura de governo federativo; compara as experiências de paradiplomacia financeira em quatro países emergentes (Argentina, Índia, México e Rússia); e faz uma síntese das experiências em comparação com o Brasil...

  16. Cut, sindicato orgânico e reforma da estrutura sindical

    OpenAIRE

    Mota, Daniel Pestana [UNESP

    2006-01-01

    O trabalho analisa o desenvolvimento do projeto cutista que visa instituir um modelo de sindicato orgânico, projeto que ganhou impulso na Proposta de Reforma Sindical enviada ao Congresso Nacional pelo Governo Lula após discussões que saíram do Fórum Nacional do Trabalho (FNT), espaço tripartite criado para discutir alterações na estrutura sindical e legislação trabalhista brasileiras. Articulou-se com a hipótese de que, por meio do citado projeto, a Central Única dos Trabalhadores (CUT) acab...

  17. A estruturação de atividades criminosas: um estudo de caso

    OpenAIRE

    Beato,Cláudio; Zilli,Luís Felipe

    2012-01-01

    Tendo como pano de fundo o problema da atuação de grupos armados ilegais em favelas e bairros pobres das periferias urbanas brasileiras, o presente artigo tem como objetivo esboçar um modelo dinâmico de estruturação de atividades criminosas, na expectativa de fornecer subsídios para uma compreensão mais abrangente e sistêmica de como o fenômeno vem se desenvolvendo no país ao longo das últimas décadas. Trabalhando sob a perspectiva de um modelo evolutivo complexo, propomos a ideia de que, a d...

  18. Patologia dos edifícios em estrutura metálica.

    OpenAIRE

    Castro, Eduardo Mariano Cavalcante de

    1999-01-01

    Programa de Pós Graduação em Engenharia Civil. Departamento de Engenharia Civil, Escola de Minas, Universidade Federal de Ouro Preto. Atualmente existem vários estudos e publicações envolvendo patologia dos edifícios no meio acadêmico, mas, na grande maioria deles, o tipo de construção abordada é aquela em que a estrutura é executada em concreto armado. Com menos ênfase, temos ainda alguns estudos envolvendo as patologias das construções em madeiras e por último, de modo bem su...

  19. Estrutura tridimensional da bothropasina, uma metaloprotease/desintegrina do veneno de bothrops jararaca

    OpenAIRE

    João Renato Carvalho Muniz

    2007-01-01

    A bothropasina é uma proteína hemorrágica de 48 kDa, pertencente à classe P-III das metaloproteases, isolada a partir do veneno bruto da serpente brasileira Bothrops jararaca, e que possui os domínios adesivos desintegrina (D) e rico em cisteína (C). Neste trabalho, nós apresentamos a estrutura cristalográfica da bothropasina complexada ao inibidor POL647. O domínio catalítico , metaloprotease (M), pode ser dividido em dois subdomínios, dispostos de maneira muito similar aos descritos para es...

  20. Nautilus Centripetal Capillary Condenser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A Nautilus Centripetal Capillary Condenser (NCCC) is proposed for the microgravity compatible removal of water from a saturated air stream. Successful development of...

  1. High temperature Bose-Einstein condensation

    Directory of Open Access Journals (Sweden)

    Begun Viktor

    2016-01-01

    Full Text Available The indications of a possible pion condensation at the LHC are summarized. The condensation is predicted by the non-equilibrium hadronization model for 2.76 TeV Pb+Pb collisions at the LHC. The model solves the proton/pion puzzle and reproduces the low pT enhancement of the pion spectra, as well as the spectra of protons and antiprotons, charged kaons, K0S, K*(8920 and ϕ(1020. The obtained parameters allow to estimate the amount of pion condensate on the level of 5% from the total number of pions at the LHC. The condensate is located at pT < 250 MeV.

  2. Kaon condensation in dense stellar matter

    International Nuclear Information System (INIS)

    Lee, Chang-Hwan; Rho, M.; Washington Univ., Seattle, WA

    1995-03-01

    This article combines two talks given by the authors and is based on Works done in collaboration with G.E. Brown and D.P. Min on kaon condensation in dense baryonic medium treated in chiral perturbation theory using heavy-baryon formalism. It contains, in addition to what was recently published, astrophysical backgrounds for kaon condensation discussed by Brown and Bethe, a discussion on a renormalization-group analysis to meson condensation worked out together with H.K. Lee and S.J. Sin, and the recent results of K.M. Westerberg in the bound-state approach to the Skyrme model. Negatively charged kaons are predicted to condense at a critical density 2 approx-lt ρ/ρo approx-lt 4, in the range to allow the intriguing new phenomena predicted by Brown and Bethe to take place in compact star matter

  3. Fundamentals of evaporation and condensation phenomena

    International Nuclear Information System (INIS)

    Munir, Z.A.

    1979-01-01

    Fundamental relationships governing evaporation and condensation processes are reviewed. The terrace-ledge-kink (TLK) model is discussed in terms of atomic steps comprising growth and evaporation of crystals. Recent results in the field are described

  4. Accretion of Ghost Condensate by Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A

    2004-06-02

    The intent of this letter is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as tenth of a solar mass per second for 10MeV-scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

  5. Recent developments in Bose-Einstein condensation

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, G.

    1997-09-22

    This paper contains viewgraphs on developments on Bose-Einstein condensation. Some topics covered are: strongly coupled coulomb systems; standard response functions of the first and second kind; dynamical mean field theory; quasi localized charge approximation; and the main equations.

  6. Interação solo-estrutura para sistemas estruturais reticulados sobre fundações rasas

    Directory of Open Access Journals (Sweden)

    R. C. Pavan

    Full Text Available Neste artigo apresenta-se um programa para consideração da interação solo-estrutura na análise espacial de estruturas reticulares. O método empregado baseia-se na hipótese de Winkler, que admite molas discretas adjacentes as fundações rasas, simulando a influência dos recalques de apoio em estruturas tridimensionais. Embora o modelo seja 3D e, portanto, todos os seis graus de liberdade de cada apoio possam sofrer deslocamentos devidos a um recalque, neste artigo, a análise foi feita considerando apenas a influência da translação verticaldos apoios. O trabalho consiste em incorporar a metodologia para consideração de apoios flexíveis aos fluxogramas apresentados por Geree Weaver Jr. [1], utilizando o Método da Rigidez, o qual é amplamente empregado para análise de estruturas reticulares. Através da análiseintegrada, contemplando parâmetros da infraestrutura, supraestrutura e do terreno de fundação, comprovou-se que a deformabilidade do solotem influência significativa na redistribuição dos esforços e a vinculação entre solo e a estrutura que melhor descreve o comportamento físicode uma edificação é condição de apoios flexíveis.

  7. Conditions for maximum isolation of stable condensate during separation in gas-condensate systems

    Energy Technology Data Exchange (ETDEWEB)

    Trivus, N.A.; Belkina, N.A.

    1969-02-01

    A thermodynamic analysis is made of the gas-liquid separation process in order to determine the relationship between conditions of maximum stable condensate separation and physico-chemical nature and composition of condensate. The analysis was made by considering the multicomponent gas-condensate fluid produced from Zyrya field as a ternary system, composed of methane, an intermediate component (propane and butane) and a heavy residue, C/sub 6+/. Composition of 5 ternary systems was calculated for a wide variation in separator conditions. At each separator pressure there is maximum condensate production at a certain temperature. This occurs because solubility of condensate components changes with temperature. Results of all calculations are shown graphically. The graphs show conditions of maximum stable condensate separation.

  8. Stabilization flyuorytopodibnoyi structure in oxide vacuum condensate

    Directory of Open Access Journals (Sweden)

    О.М. Заславський

    2006-01-01

    Full Text Available  The influence of the oxide-stabilizer content, M'-cation radius and film deposition temperature on the stabilization of the fluorite-like solid solutions in the zirconium and hafnium oxides-based vacuum condensates, obtained by Laser-evaporating method, was investigated. The optimum parameters of the coatication of the isotropic thermostable coverings was determined. This results were explained by using of the high-speed condensation in vacuum theory.

  9. Gauge independence of the Ao-condensate

    International Nuclear Information System (INIS)

    Skalozub, V.V.

    1992-01-01

    The problem of gauge dependence of the zero gauge field component condensate. A o =const, in the framework of finite temperature SU(2) gluodynamics is investigated. In straight-forward calculations it is shown that the two-loop effective action W(A o ,ζ) satisfies the generalized Nielsen identity. Thus, the gauge invariance of the A o -condensation is proved. 12 refs. (author)

  10. Condenser cooling water quality at Kaiga

    International Nuclear Information System (INIS)

    Namboodiri, E.G.A.

    1995-01-01

    Once-through circulation of river water is envisaged in Kaiga for cooling the condenser and other related equipment. Water drawn from Kali river will be used for this purpose. After cooling the condenser, the water is let into the river through the outfall system. The materials used in the cooling water system consist mainly of SS 316 and carbon steel. Chlorination is the treatment proposed to the cooling water. The cooling water quality is found to be satisfactory. (author). 2 refs

  11. Condensate of massive graviton and dark matter

    OpenAIRE

    Aoki, Katsuki; Maeda, Kei-ichi

    2018-01-01

    We study coherently oscillating massive gravitons in the ghost-free bigravity theory. This coherent field can be interpreted as a condensate of the massive gravitons. We first define the effective energy-momentum tensor of the coherent massive gravitons in a curved spacetime. We then study the background dynamics of the universe and the cosmic structure formation including the effects of the coherent massive gravitons. We find that the condensate of the massive graviton behaves as a dark matt...

  12. Vector condensate model of electroweak interactions

    International Nuclear Information System (INIS)

    Cynolter, G.; Pocsik, G.

    1997-01-01

    Motivated by the fact that the Higgs is not seen, a new version of the standard model is proposed where the scalar doublet is replaced by a vector doublet and its neutral member forms a nonvanishing condensate. Gauge fields are coupled to the new vector fields B in a gauge invariant way leading to mass terms for the gauge fields by condensation. The model is presented and some implications are discussed. (K.A.)

  13. Fermion condensation and gapped domain walls in topological orders

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Yidun [Department of Physics and Center for Field Theory and Particle Physics, Fudan University,Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University,Nanjing 210093 (China); Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada); Wang, Chenjie [Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada)

    2017-03-31

    We study fermion condensation in bosonic topological orders in two spatial dimensions. Fermion condensation may be realized as gapped domain walls between bosonic and fermionic topological orders, which may be thought of as real-space phase transitions from bosonic to fermionic topological orders. This picture generalizes the previous idea of understanding boson condensation as gapped domain walls between bosonic topological orders. While simple-current fermion condensation was considered before, we systematically study general fermion condensation and show that it obeys a Hierarchy Principle: a general fermion condensation can always be decomposed into a boson condensation followed by a minimal fermion condensation. The latter involves only a single self-fermion that is its own anti-particle and that has unit quantum dimension. We develop the rules of minimal fermion condensation, which together with the known rules of boson condensation, provides a full set of rules for general fermion condensation.

  14. Spatial Control of Condensation using Chemical Micropatterns

    Science.gov (United States)

    Murphy, Kevin; Hansen, Ryan; Nath, Saurabh; Retterer, Scott; Collier, Patrick; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team; CenterNanophase Materials Sciences Team

    2015-11-01

    Surfaces exhibiting wettability patterns can spatially control the nucleation of condensation to enable enhanced fog harvesting and phase-change heat transfer. To date, studies of patterned condensation have utilized a combination of chemical and topographical features, making it difficult to isolate the effects of intrinsic wettability versus surface roughness on spatially controlling the condensate. Here, we fabricate chemical micropatterns consisting of hydrophilic silicon oxide and a smooth hydrophobic silane monolayer to isolate the effects of changes in intrinsic wettability on the spatial control of condensation. Complete spatial control, defined as every nucleation and growth event occurring exclusively on the hydrophilic features, was observed even for supercooled droplets at high water vapor supersaturation. However, this complete spatial control was found to break down beyond a critical spacing that depended upon the extent of supersaturation. The average diameter of condensate was found to be smaller for the chemically micropatterned surfaces compared to a uniformly hydrophobic surface. Control of inter-droplet spacing between supercooled condensate through chemical patterning can be employed to minimize the growth of inter-droplet frost on cold surfaces.

  15. Primes, Geometry and Condensed Matter

    Directory of Open Access Journals (Sweden)

    Al Rabeh R. H.

    2009-07-01

    Full Text Available Fascination with primes dates back to the Greeks and before. Primes are named by some “the elementary particles of arithmetic” as every nonprime integer is made of a unique set of primes. In this article we point to new connections between primes, geometry and physics which show that primes could be called “the elementary particles of physics” too. This study considers the problem of closely packing similar circles / spheres in 2D / 3D space. This is in effect a discretization process of space and the allowable num- ber in a pack is found to lead to some unexpected cases of prime configurations which is independent of the size of the constituents. We next suggest that a non-prime can be considered geometrically as a symmetric collection that is separable (factorable into similar parts- six is two threes or three twos for example. A collection that has no such symmetry is a prime. As a result, a physical prime aggregate is more difficult to split symmetrically resulting in an inherent stability. This “number / physical” stability idea applies to bigger collections made from smaller (prime units leading to larger sta- ble prime structures in a limitless scaling up process. The distribution of primes among numbers can be understood better using the packing ideas described here and we further suggest that differing numbers (and values of distinct prime factors making a nonprime collection is an important factor in determining the probability and method of possible and subsequent disintegration. Disintegration is bound by energy conservation and is closely related to symmetry by Noether theorems. Thinking of condensed matter as the packing of identical elements, we examine plots of the masses of chemical elements of the periodic table, and also those of the elementary particles of physics, and show that prime packing rules seem to play a role in the make up of matter. The plots show con- vincingly that the growth of prime numbers and that

  16. Primes, Geometry and Condensed Matter

    Directory of Open Access Journals (Sweden)

    Al Rabeh R. H.

    2009-07-01

    Full Text Available Fascination with primes dates back to the Greeks and before. Primes are named by some "the elementary particles of arithmetic" as every nonprime integer is made of a unique set of primes. In this article we point to new connections between primes, geometry and physics which show that primes could be called "the elementary particles of physics" too. This study considers the problem of closely packing similar circles/spheres in 2D/3D space. This is in effect a discretization process of space and the allowable number in a pack is found to lead to some unexpected cases of prime configurations which is independent of the size of the constituents. We next suggest that a non-prime can be considered geometrically as a symmetric collection that is separable (factorable into similar parts- six is two threes or three twos for example. A collection that has no such symmetry is a prime. As a result, a physical prime aggregate is more difficult to split symmetrically resulting in an inherent stability. This "number/physical" stability idea applies to bigger collections made from smaller (prime units leading to larger stable prime structures in a limitless scaling up process. The distribution of primes among numbers can be understood better using the packing ideas described here and we further suggest that differing numbers (and values of distinct prime factors making a nonprime collection is an important factor in determining the probability and method of possible and subsequent disintegration. Disintegration is bound by energy conservation and is closely related to symmetry by Noether theorems. Thinking of condensed matter as the packing of identical elements, we examine plots of the masses of chemical elements of the periodic table, and also those of the elementary particles of physics, and show that prime packing rules seem to play a role in the make up of matter. The plots show convincingly that the growth of prime numbers and that of the masses of

  17. Mitotic chromosome condensation in vertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Vagnarelli, Paola, E-mail: P.Vagnarelli@ed.ac.uk

    2012-07-15

    Work from several laboratories over the past 10-15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292-301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories-a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307-316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119-1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579-589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different classes

  18. Mitotic chromosome condensation in vertebrates

    International Nuclear Information System (INIS)

    Vagnarelli, Paola

    2012-01-01

    Work from several laboratories over the past 10–15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292–301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories—a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307–316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119–1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579–589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different

  19. Descontinuidades produtivas e tecnológicas na estrutura industrial da economia brasileira

    Directory of Open Access Journals (Sweden)

    Rosembergue Valverde

    Full Text Available Resumo O objetivo deste artigo é avaliar a capacidade da economia brasileira de sustentar taxas de crescimento em longo prazo, considerando as complementaridades técnicas intersetoriais como vetor de absorção e difusão tecnológicas na estrutura industrial. Para realizar essa tarefa, recorre-se às teorias neo-schumpeteriana, que descrevem os processos de absorção e difusão tecnológicas e à construção de um modelo de crescimento multissetorial de inspiração neorricardiana do tipo Sraffa-Von Neumann. Em acordo com os procedimentos metodológicos adotados, identificam-se descontinuidades produtivas, características de estrangulamentos da produção, que comprometem as condições de crescimento de longo prazo e os processos de absorção e difusão tecnológicas da economia brasileira. Em conclusão, destaca-se a existência de pontos de estrangulamentos de produção em setores com elevado grau de basicidade, fundamentais para a reprodução da estrutura produtiva da economia brasileira.

  20. Biologia de ninfas e adultos do percevejo-verde em estruturas reprodutivas de algodoeiro

    Directory of Open Access Journals (Sweden)

    Rosalia Azambuja

    2014-06-01

    Full Text Available O objetivo deste trabalho foi determinar a biologia de ninfas e adultos do percevejo-verde em estruturas reprodutivas do algodoeiro. Os alimentos testados foram: dieta padrão, contendo vagem de feijão, amendoim cru e frutos de ligustro; vagem verde de soja; semente de soja; botão floral de algodoeiro; e maçãs e sementes de algodoeiro. Foram avaliados os parâmetros biológicos: período de desenvolvimento e sobrevivência ninfal; longevidade de fêmeas e machos; percentagem de fêmeas em oviposição; períodos de pré-oviposição e oviposição; número total de ovos por fêmea; e viabilidade dos ovos. Ninfas alimentadas com estruturas reprodutivas do algodoeiro morreram no segundo ou no terceiro ínstar. Adultos alimentados com botão floral e semente de algodoeiro não se reproduzem; porém, há reprodução quando adultos os de percevejo-verde são alimentados com maçã de algodoeiro, o que indica a capacidade de adaptação da espécie na fase reprodutiva do algodoeiro.

  1. BSC E A ESTRUTURA DE ATRIBUTOS DA CONTABILIDADE GERENCIAL: UMA ANÁLISE NO AMBIENTE BRASILEIRO

    Directory of Open Access Journals (Sweden)

    Fábio Frezatti

    2010-04-01

    Full Text Available Este artigo tem por objetivo investigar se existe associação entre a estrutura de atributos da contabilidade gerencial e a existênciado balanced scorecard (BSC em empresas brasileiras. A pesquisa utilizou a estrutura de atributos da contabilidadegerencial desenvolvida por Chenhall e Morris (1986 e aperfeiçoada por Moores e Yuen (2001. Por meio dessa associação,buscou-se identificar as características das empresas que implantaram ou estão em fase de implementação do BSC e analisaras possíveis causas para sua pouca utilização. Foi possível identificar relações significativas entre a implantação do BSC e osatributos da contabilidade gerencial em três dos quatro grupos de empresas discriminados pelas variáveis de questionamento.A utilidade do conhecimento revelado reside no potencial de orientação aos gestores quanto aos requisitos e condiçõesestruturais para uso do BSC, diminuindo o risco de insucesso e facilitando a implementação.

  2. O toxicômano: dados psico-sociais e estrutura psico-dinâmica

    Directory of Open Access Journals (Sweden)

    Richard Bucher

    Full Text Available Toxicómanos foram examinados mediante um questionário e o teste projetivo de Szondi. A divisão em três grupos (dois masculinos e um feminino permitiu efetuar comparações estatísticas e interpretar as estruturas pulsionais bem como suas características diferenciais. Os resultados do teste de Szondi revelam um desequilíbrio profundo da personalidade e de suas possibilidades de relacionar-se com outros, sendo que estas dificuldades afetam os dois sexos de maneira diferente. Ambos os grupos em cura de desintoxicação apresentam numerosos sintomas psicopatológicos, consequências prováveis tanto do consumo de tóxicos como de desestruturações anteriores. O terceiro grupo (toxicômanos encarcerados apresenta conflitos que parecem ser mais diretamente sociais do que familiares ou psicológicos. Nos outros grupos, as dificuldades de estruturação psíquica e de integração psicossocial parecem ser devidas à problemática familiar.

  3. Estrutura e organização espacial de duas comunidades de anuros do bioma Pampa

    Directory of Open Access Journals (Sweden)

    Victor M. Lipinski

    2014-12-01

    Full Text Available O Pampa é o menor bioma brasileiro e está entre os mais ameaçados devido ao rápido avanço das culturas agropastoris e da silvicultura; é um dos biomas com menor representação no sistema de unidades de conservação. Neste estudo são apresentadas informações sobre a estrutura e a organização espacial das comunidades de anuros de duas das quatro regiões fisiográficas em que o bioma é dividido. Foram amostrados dez corpos d’água em cada região entre os meses de setembro de 2011 e agosto de 2012. Foram registradas 24 espécies caracterizadas como generalistas, de ampla distribuição e típicas de ambientes abertos. A curva de acumulação de espécies apresentou a formação de uma assíntota após o 12° mês de amostragem. A análise de similaridade mostrou uma segregação na estrutura das duas comunidades, que foram influenciadas pelos descritores ambientais e da paisagem.

  4. Implementation of non-condensable gases condensation suppression model into the WCOBRA/TRAC-TF2 LOCA safety evaluation code

    International Nuclear Information System (INIS)

    Liao, J.; Cao, L.; Ohkawa, K.; Frepoli, C.

    2012-01-01

    The non-condensable gases condensation suppression model is important for a realistic LOCA safety analysis code. A condensation suppression model for direct contact condensation was previously developed by Westinghouse using first principles. The model is believed to be an accurate description of the direct contact condensation process in the presence of non-condensable gases. The Westinghouse condensation suppression model is further revised by applying a more physical model. The revised condensation suppression model is thus implemented into the WCOBRA/TRAC-TF2 LOCA safety evaluation code for both 3-D module (COBRA-TF) and 1-D module (TRAC-PF1). Parametric study using the revised Westinghouse condensation suppression model is conducted. Additionally, the performance of non-condensable gases condensation suppression model is examined in the ACHILLES (ISP-25) separate effects test and LOFT L2-5 (ISP-13) integral effects test. (authors)

  5. Avaliação visual da qualidade da estrutura do solo em sistemas de uso das terras

    OpenAIRE

    Joelcio Eurich; Pedro Henrique Weirich Neto; Carlos Hugo Rocha; Zíngara Rocio dos Santos Eurich

    2014-01-01

    Sistemas sustentáveis de produção agropecuária demandam solos com boa estrutura, por isso, são necessários métodos eficientes para avaliação dessa estrutura. Objetivou-se, com este estudo, aplicar a metodologia de avaliação visual da estrutura do solo, em áreas previamente cobertas por Floresta com Araucária, em longo período de uso após o desmatamento. Selecionaram-se áreas sob três tipos de usos: floresta nativa, pastagem e cultivo agrícola, considerados como tratamento, sendo realizadas de...

  6. Cold Vacuum Drying facility condensate collection system design description

    International Nuclear Information System (INIS)

    PITKOFF, C.C.

    1999-01-01

    This document describes the Cold Vacuum Drying Facility (CVDF) condensate collection system (CCS). The function of the CCS is to collect cooling coil condensate from air-handling units in the CVDF and to isolate the condensate in collection tanks until the condensate is determined to be acceptable to drain to the effluent drain collection basin

  7. Estrutura genética da população de Sclerotinia sclerotiorum em feijoais de Minas Gerais

    OpenAIRE

    Lehner, Miller da Silva

    2011-01-01

    O conhecimento sobre a estrutura genética da população de Sclerotinia sclerotiorum é importante para direcionar as estratégias de controle do mofo-branco do feijoeiro, principalmente o desenvolvimento e uso de cultivares resistentes ao patógeno. Objetivou-se estudar a estrutura genética das populações de S. sclerotiorum em lavouras de feijão em Minas Gerais. Analisaram-se 127 isolados provenientes de quatro regiões produtoras de feijão (subpopulações) em Minas Gerais quanto ...

  8. Comportamento de atributos relacionados com a forma da estrutura de Latossolo Vermelho sob sistemas de preparo e plantas de cobertura

    OpenAIRE

    Argenton,Jeferson; Albuquerque,Jackson Adriano; Bayer,Cimélio; Wildner,Leandro do Prado

    2005-01-01

    Os sistemas de preparo de solo e de culturas têm influência significativa na estrutura do solo e nos fluxos de água e ar. Este trabalho objetivou avaliar os efeitos do manejo do solo sobre as propriedades relacionadas com estrutura de um Latossolo Vermelho cultivado com milho intercalado com plantas de cobertura de verão. Dois experimentos foram realizados em Chapecó (SC), em preparo reduzido (PR), de 1993 a 1998, e preparo convencional (PC), de 1994 a 1998, nos quais foram avaliados três sis...

  9. Estrutura das maternidades: aspectos relevantes para a qualidade da atenção ao parto e nascimento

    OpenAIRE

    Bittencourt, Sonia Duarte de Azevedo; Reis, Lenice Gnocchi da Costa; Ramos, Márcia Melo; Rattner, Daphne; Rodrigues, Patrícia Lima; Neves, Dilma Costa Oliveira; Arantes, Sandra Lúcia; Leal, Maria do Carmo

    2014-01-01

    Avaliar aspectos da estrutura de uma amostra de maternidades do Brasil. A estrutura foi avaliada tendo como referências as normas do Ministério da Saúde e englobou: localização geográfica, volume de partos, existência de UTI, atividade de ensino, qualificação de recursos humanos, disponibilidade de equipamentos e medicamentos. Os resultados evidenciam diferenças na qualificação e na disponibilidade de equipamentos e insumos dos serviços de atenção ao parto e nascimento segundo o tipo de finan...

  10. Influência da estrutura molecular dos policarboxilatos na hidratação do cimento Portland

    OpenAIRE

    Rojas,Carolina Martínez; Cincotto,Maria Alba

    2013-01-01

    O objetivo deste trabalho é apresentar os dados de literatura que enfatizam a influência da estrutura molecular de policarboxilatos na hidratação do cimento, estudada por ensaios de calor de hidratação, tempos de pega e análise termogravimétrica em pastas de cimento. Com essa mesma metodologia foram avaliados dois policarboxilatos, agente ativo de dois aditivos nacionais cujas estruturas moleculares diferem no tamanho das cadeias laterais. Tanto os dados da literatura quanto os resultados dos...

  11. A influência da estrutura organizacional na execução das atividades de marketing

    OpenAIRE

    Roberto Fava Scare

    2008-01-01

    O estudo sobre organização de marketing e estruturas organizacionais de marketing é crucial para a implementação dos esforços de marketing, principalmente em um cenário competitivo em que as empresas precisam modificar constantemente suas estratégias e suas estruturas para atender às novas exigências do mercado. Apesar de histórico, esse debate é atualmente relegado a segundo plano por pesquisadores e executivos de marketing, sendo a proposta desta tese reavivar essa discussão. Assim, o objet...

  12. Improved condenser design and condenser-fan operation for air-cooled chillers

    International Nuclear Information System (INIS)

    Yu, F.W.; Chan, K.T.

    2006-01-01

    Air-cooled chillers traditionally operate under head pressure control via staging constant-speed condenser fans. This causes a significant drop in their coefficient of performance (COP) at part load or low outdoor temperatures. This paper describes how the COP of these chillers can be improved by a new condenser design, using evaporative pre-coolers and variable-speed fans. A thermodynamic model for an air-cooled screw-chiller was developed, within which the condenser component considers empirical equations showing the effectiveness of an evaporative pre-cooler in lowering the outdoor temperature in the heat-rejection process. The condenser component also contains an algorithm to determine the number and speed of the condenser fans staged at any given set point of condensing temperature. It is found that the chiller's COP can be maximized by adjusting the set point based on any given chiller load and wet-bulb temperature of the outdoor air. A 5.6-113.4% increase in chiller COP can be achieved from the new condenser design and condenser fan operation. This provides important insights into how to develop more energy-efficient air-cooled chillers

  13. GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS BETWEEN ASSAYS AND CONDENSATES

    Science.gov (United States)

    What is the study? This the first assessment of a set of cigarette smoke condensates from a range of cigarette types in a variety (4) of short-term genotoxicity assays. Why was it done? No such comparative study of cigarette smoke condensates has been reported. H...

  14. Steam condensation modelling in aerosol codes

    International Nuclear Information System (INIS)

    Dunbar, I.H.

    1986-01-01

    The principal subject of this study is the modelling of the condensation of steam into and evaporation of water from aerosol particles. These processes introduce a new type of term into the equation for the development of the aerosol particle size distribution. This new term faces the code developer with three major problems: the physical modelling of the condensation/evaporation process, the discretisation of the new term and the separate accounting for the masses of the water and of the other components. This study has considered four codes which model the condensation of steam into and its evaporation from aerosol particles: AEROSYM-M (UK), AEROSOLS/B1 (France), NAUA (Federal Republic of Germany) and CONTAIN (USA). The modelling in the codes has been addressed under three headings. These are the physical modelling of condensation, the mathematics of the discretisation of the equations, and the methods for modelling the separate behaviour of different chemical components of the aerosol. The codes are least advanced in area of solute effect modelling. At present only AEROSOLS/B1 includes the effect. The effect is greater for more concentrated solutions. Codes without the effect will be more in error (underestimating the total airborne mass) the less condensation they predict. Data are needed on the water vapour pressure above concentrated solutions of the substances of interest (especially CsOH and CsI) if the extent to which aerosols retain water under superheated conditions is to be modelled. 15 refs

  15. Increasing the efficiency of the condensing boiler

    Science.gov (United States)

    Zaytsev, ON; Lapina, EA

    2017-11-01

    Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

  16. Laser Isotope Separation Employing Condensation Repression

    Energy Technology Data Exchange (ETDEWEB)

    Eerkens, Jeff W.; Miller, William H.

    2004-09-15

    Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

  17. The NSF Condensed Matter Physics Program

    Science.gov (United States)

    Sokol, Paul

    The Condensed Matter Physics (CMP) program in the NSF Division of Materials Research (DMR) supports experimental, as well as combined experiment and theory projects investigating the fundamental physics behind phenomena exhibited by condensed matter systems. CMP is the largest Individual Investigator Award program in DMR and supports a broad portfolio of research spanning both hard and soft condensed matter. Representative research areas include: 1) phenomena at the nano- to macro-scale including: transport, magnetic, and optical phenomena; classical and quantum phase transitions; localization; electronic, magnetic, and lattice structure or excitations; superconductivity; topological insulators; and nonlinear dynamics. 2) low-temperature physics: quantum fluids and solids; 1D & 2D electron systems. 3) soft condensed matter: partially ordered fluids, granular and colloid physics, liquid crystals, and 4) understanding the fundamental physics of new states of matter as well as the physical behavior of condensed matter under extreme conditions e.g., low temperatures, high pressures, and high magnetic fields. In this talk I will review the current CMP portfolio and discuss future funding trends for the program. I will also describe recent activities in the program aimed at addressing the challenges facing current and future principal investigators.

  18. Condensate and feedwater systems, pumps, and water chemistry. Volume seven

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Subject matter includes condensate and feedwater systems (general features of condensate and feedwater systems, condenser hotwell level control, condensate flow, feedwater flow), pumps (principles of fluid flow, types of pumps, centrifugal pumps, positive displacement pumps, jet pumps, pump operating characteristics) and water chemistry (water chemistry fundamentals, corrosion, scaling, radiochemistry, water chemistry control processes, water pretreatment, PWR water chemistry, BWR water chemistry, condenser circulating water chemistry

  19. Heavy-quark expansion, factorization and 8-dimensional gluon condensates

    International Nuclear Information System (INIS)

    Bagan, E.; Latorre, J.I.; Pascual, P.; Tarrach, R.

    1985-01-01

    We analyze the phenomenon of heavy-quark condensation within the framework of the QCD sum rule approach, and apply the consequences of this analysis to the heavy-quark expansion. This technique allows one to relate 6-dimensional quark condensates with quartic 8-dimensional gluon condensates. Factorization of the quark condensates together with the specific feature of 3 condensates, which we believe to be well-founded. (orig.)

  20. Preoperational test report, recirculation condenser cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  1. Preoperational test report, recirculation condenser cooling systems

    International Nuclear Information System (INIS)

    Clifton, F.T.

    1997-01-01

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

  2. Bose-Einstein condensation of atomic gases

    International Nuclear Information System (INIS)

    Anglin, J. R.; Ketterle, W.

    2003-01-01

    The early experiments on Bose-Einstein condensation in dilute atomic gases accomplished three longstanding goals. First, cooling of neutral atoms into their motional state, thus subjecting them to ultimate control, limited only by Heisenberg uncertainty relation. Second, creation of a coherent sample of atoms, in which all occupy the same quantum states, and the realization of atom lasers - devices that output coherent matter waves. And third, creation of gaseous quantum fluid, with properties that are different from the quantum liquids helium-3 and helium-4. The field of Bose-Einstein condensation of atomic gases has continued to progress rapidly, driven by the combination of new experimental techniques and theoretical advances. The family of quantum degenerate gases has grown, and now includes metastable and fermionic atoms. condensates have become an ultralow-temperature laboratory for atom optics, collisional physics and many-body physics, encompassing phonons, superfluidity, quantized vortices, Josephson junctions and quantum phase transitions. (author)

  3. From particle condensation to polymer aggregation

    Science.gov (United States)

    Janke, Wolfhard; Zierenberg, Johannes

    2018-01-01

    We draw an analogy between droplet formation in dilute particle and polymer systems. Our arguments are based on finite-size scaling results from studies of a two-dimensional lattice gas to three-dimensional bead-spring polymers. To set the results in perspective, we compare with in part rigorous theoretical scaling laws for canonical condensation in a supersaturated gas at fixed temperature, and derive corresponding scaling predictions for an undercooled gas at fixed density. The latter allows one to efficiently employ parallel multicanonical simulations and to reach previously not accessible scaling regimes. While the asymptotic scaling can not be observed for the comparably small polymer system sizes, they demonstrate an intermediate scaling regime also observable for particle condensation. Altogether, our extensive results from computer simulations provide clear evidence for the close analogy between particle condensation and polymer aggregation in dilute systems.

  4. Dropwise condensation on inclined textured surfaces

    CERN Document Server

    Khandekar, Sameer

    2014-01-01

    Dropwise Condensation on Textured Surfaces presents a holistic framework for understanding dropwise condensation through mathematical modeling and meaningful experiments. The book presents a review of the subject required to build up models as well as to design experiments. Emphasis is placed on the effect of physical and chemical texturing and their effect on the bulk transport phenomena. Application of the model to metal vapor condensation is of special interest. The unique behavior of liquid metals, with their low Prandtl number and high surface tension, is also discussed. The model predicts instantaneous drop size distribution for a given level of substrate subcooling and derives local as well as spatio-temporally averaged heat transfer rates and wall shear stress.

  5. Condensate of massive graviton and dark matter

    Science.gov (United States)

    Aoki, Katsuki; Maeda, Kei-ichi

    2018-02-01

    We study coherently oscillating massive gravitons in the ghost-free bigravity theory. This coherent field can be interpreted as a condensate of the massive gravitons. We first define the effective energy-momentum tensor of the coherent massive gravitons in a curved spacetime. We then study the background dynamics of the Universe and the cosmic structure formation including the effects of the coherent massive gravitons. We find that the condensate of the massive graviton behaves as a dark matter component of the Universe. From the geometrical point of view the condensate is regarded as a spacetime anisotropy. Hence, in our scenario, dark matter is originated from the tiny deformation of the spacetime. We also discuss a production of the spacetime anisotropy and find that the extragalactic magnetic field of a primordial origin can yield a sufficient amount for dark matter.

  6. Temporal dynamics of Bose-condensed gases

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo Martinez, Mauricio

    2014-03-19

    We perform a detailed quantum dynamical study of non-equilibrium trapped, interacting Bose-condensed gases. We investigate Josephson oscillations between interacting Bose-Einstein condensates confined in a finite size double-well trap and the non-trivial time evolution of a coherent state placed at the center of a two dimensional optical lattice. For the Josephson oscillations three time scales appear. We find that Josephson junction can sustain multiple undamped oscillations up to a characteristic time scale τ{sub c} without exciting atoms out of the condensates. Beyond the characteristic time scale τ{sub c} the dynamics of the junction are governed by fast, non-condensed particles assisted Josephson tunnelling as well as the collisions between non-condensed particles. In the non-condensed particles dominated regime we observe strong damping of the oscillations due to inelastic collisions, equilibrating the system leading to an effective loss of details of the initial conditions. In addition, we predict that an initially self-trapped BEC state will be destroyed by these fast dynamics. The time evolution of a coherent state released at the center of a two dimensional optical lattice shows a ballistic expansion with a decreasing expansion velocity for increasing two-body interactions strength and particle number. Additionally, we predict that if the two-body interactions strength exceeds a certain value, a forerunner splits up from the expanding coherent state. We also observe that this system, which is prepared far from equilibrium, can evolve to a quasistationary non-equilibrium state.

  7. Estrutura de bases de dados: modelos de metadados e a qualidade de resposta

    Directory of Open Access Journals (Sweden)

    Marta Lígia Pomim Valentim

    Full Text Available A estrutura das bases de dados, bem como a forma com que as bases de dados desenham seu modelo de dados são objetos de análise deste artigo. Alguns tipos de bases de dados, como: bibliográficas, diretórios, fiannceiras, numéricas e texto completo, são analisadas a partir das diferentes tipologias documentais que as compõem e a relação com o desenho do modelo de dados utilizados por elas. A partir disso, defende-se a hipótese de que qunato melhor desenhado o modelo de dados em relação as diferentes tipologias documentais, maior será a qualidade de resposta da base de dados.

  8. Projeto de estruturas com perfis em aço enformados a frio

    OpenAIRE

    Bastos, Rui Paulo Soares de

    2014-01-01

    Nesta dissertação apresentará alguns dos principais materiais empregues nas construções com perfis em aço leves ou Light Steel Framing, habitualmente designado por LSF. Apresenta-se também a conhecer o processo construtivo desde a fundação até a cobertura. As construções em LSF são construções a seco com estruturas em aço galvanizado e placas estruturais de OSB, que posteriormente é revestida com materiais de qualidade. Este método em LSF aborda e colmata de forma eficaz as lacunas ecológicas...

  9. Estrutura das taxocenoses de lagartos nos biomas caatinga, cerrado e Amazônia.

    OpenAIRE

    Costa, Taís Borges

    2015-01-01

    A tese está dividida em três capítulos. No primeiro capítulo apresentamos a lista de espécies de répteis e anfíbios da Estação Ecológica de Aiuaba, Ceará, Brasil. Registramos 36 espécies distribuídas em 19 famílias para a unidade de conservação (15 lagartos, uma anfisbena, 10 serpentes, um quelônio e 9 anfíbios). No segundo capítulo investigamos a existência de padrões de estruturação, averiguando a influência dos fatores ecológicos e históricos, na dieta e no uso de microhábit...

  10. Composition of gases vented from a condenser

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, R.N.

    1980-08-01

    Designers of systems that involve condensers often need to predict the amount of process vapor that accompanies the noncondensable gases that are vented from the condensers. An approximation is given that appears to provide, in many cases, reasonably accurate values for the mole ratio of process vapor to noncondensable gases in the vented mixture. The approximation is particularly applicable to flash and direct-contact power systems for geothermal brines and ocean thermal energy conversion (OTEC). More regorous relationships are available for exceptional cases.

  11. Bose-condensation through resonance decay

    International Nuclear Information System (INIS)

    Ornik, U.; Pluemer, M.; Strottman, D.

    1993-04-01

    We show that a system described by an equation of state which contains a high number of degrees of freedom (resonances) can create a considerable amount of superfluid (condensed) pions through the decay of short-lived resonances, if baryon number and entropy are large and the dense matter decouples from chemical equilibrium earlier than from thermal equilibrium. The system cools down faster in the presence of a condensate, an effect that may partially compensate the enhancement of the lifetime expected in the case of quark-gluon-plasma formation. (orig.). 3 figs

  12. Tunneling problems between Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Watabe, Shohei; Kato, Yusuke

    2009-01-01

    We investigate transmission and reflection of Bose-Einstein condensate excitations in the low-energy limit across a potential barrier separating two condensates with different densities. Bogoliubov excitation in the low-energy limit has an incident angle where perfect transmission occurs. This condition corresponds to the Brewster's law for the electromagnetic wave. There also exists the total internal reflection of the Bogoliubov excitation in the low-energy limit. In the case of the normal incidence, our result in the low-energy limit is consistent with a result for weakly interacting one-dimensional Bose gases treated as Tomonaga-Luttinger liquids.

  13. Tunneling problems between Bose-Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Watabe, Shohei [Department of Physics, University of Tokyo, Tokyo, Tokyo, 113-0033 (Japan); Kato, Yusuke [Department of Basic Science, University of Tokyo, Tokyo, 153-8902 (Japan)], E-mail: watabe@vortex.c.u-tokyo.ac.jp

    2009-02-01

    We investigate transmission and reflection of Bose-Einstein condensate excitations in the low-energy limit across a potential barrier separating two condensates with different densities. Bogoliubov excitation in the low-energy limit has an incident angle where perfect transmission occurs. This condition corresponds to the Brewster's law for the electromagnetic wave. There also exists the total internal reflection of the Bogoliubov excitation in the low-energy limit. In the case of the normal incidence, our result in the low-energy limit is consistent with a result for weakly interacting one-dimensional Bose gases treated as Tomonaga-Luttinger liquids.

  14. Turbulent meson condensation in quark deconfinement

    Directory of Open Access Journals (Sweden)

    Koji Hashimoto

    2015-06-01

    Full Text Available In a QCD-like strongly coupled gauge theory at large Nc, using the AdS/CFT correspondence, we find that heavy quark deconfinement is accompanied by a coherent condensation of higher meson resonances. This is revealed in non-equilibrium deconfinement transitions triggered by static, as well as quenched electric fields even below the Schwinger limit. There, we observe a “turbulent” energy flow to higher meson modes, which finally results in the quark deconfinement. Our observation is consistent with seeing deconfinement as a condensation of long QCD strings.

  15. Colored condensates deep inside neutron stars

    Directory of Open Access Journals (Sweden)

    Blaschke David

    2014-01-01

    Full Text Available It is demonstrated how in the absence of solutions for QCD under conditions deep inside compact stars an equation of state can be obtained within a model that is built on the basic symmetries of the QCD Lagrangian, in particular chiral symmetry and color symmetry. While in the vacuum the chiral symmetry is spontaneously broken, it gets restored at high densities. Color symmetry, however, gets broken simultaneously by the formation of colorful diquark condensates. It is shown that a strong diquark condensate in cold dense quark matter is essential for supporting the possibility that such states could exist in the recently observed pulsars with masses of 2 Mʘ.

  16. Impactos da Modernização Sobre as Estruturas Sociais: O Exemplo dos Pecuaristas de Poconé-MT

    Directory of Open Access Journals (Sweden)

    André Luiís Ribeiro Lacerda

    2015-06-01

    Full Text Available Este trabalho parte da constatação de um processo social de transformação, identificado na estrutura do status ocupacional de pecuarista pantaneiro, a partir de entrevistas de surveys realizadas entre 2014 e 2015 com pecuaristas pantaneiros que têm propriedades no município de Poconé-MT. Considerando o status ocupacional como variável dependente, identificamos algumas variáveis familiares ao que a literatura sociológica chama de teoria da modernização e que consideramos potenciais variáveis independentes. A hipótese de que o impacto da modernização nas estruturas sociais parece uma boa explicação para as transformações na estrutura ocupacional de pecuarista pantaneiro é defendida a partir do que os trabalhos empíricos sociológicos chamam de padrões de movimento nas estruturas ocupacionais de maneira geral e da relação entre o background dos fazendeiros e o processo de estratificação social.

  17. Nova filosofia de cálculo de estruturas de aço-eurocódigo 3

    OpenAIRE

    Ramos, Rui António Rodrigues

    1993-01-01

    Dissertação apresentada para obtenção do grau de Mestre em Estruturas de Engenharia Civil, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor José António F. Mota Freitas

  18. Estrutura e personalidade na neurose: da metapsicologia do sintoma à narrativa do sofrimento

    Directory of Open Access Journals (Sweden)

    Christian Ingo Lenz Dunker

    2014-04-01

    Full Text Available Neste artigo, originalmente uma aula para concurso de professor titular junto ao Instituto de Psicologia da USP, são examinadas as noções de personalidade e de estrutura em sua aplicação ao diagnóstico de neurose, em psicopatologia de extração psicanalítica. Examina-se a consistência das relações de ordem, classe e gênero, que, por hipótese, ao lado da concepção de causalidade, subsidiam a força e pertinência de uma categoria diagnóstica. Discute-se o valor da exceção e a potência normativa de conformação da experiência clínica à racionalidade diagnóstica. Os resultados deste exame epistemológico preliminar nos levam a propor a tese crítica de que há menos homogeneidade no emprego da noção freudiana de neurose do que a recepção corrente vem admitindo. Argumenta-se que cada modelo metapsicológico, no qual emergem redefinições de neurose, corresponde a uma valência narrativa e uma forma de sofrimento distinto, sendo a exclusão da narrativa de sofrimento uma dimensão relevante para reconsiderar a noção de personalidade e de estrutura na diagnóstica psicanalítica.

  19. Pollen grains are efficient cloud condensation nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pope, F D, E-mail: fdp21@cam.ac.uk [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2010-10-15

    This letter presents a laboratory study investigating the ability of pollen grains to act as cloud condensation nuclei. The hygroscopicity of pollen is measured under subsaturated relative humidities using an electrodynamic balance. It is found, along with other results, that pollen exhibits bulk uptake of water under subsaturated conditions. Through the use of an environmental scanning electron microscope it was observed that the surface of pollen is wettable at high subsaturated humidities. The hygroscopic response of the pollen to subsaturated relative humidities is parametrized using {kappa}-Koehler theory and values of the parameter {kappa} for pollen are between 0.05 and 0.1. It is found that while pollen grains are only moderately hygroscopic, they can activate at critical supersaturations of 0.001% and lower, and thus pollen grains will readily act as cloud condensation nuclei. While the number density of pollen grains is too low for them to represent a significant global source of cloud condensation nuclei, the large sizes of pollen grains suggest that they will be an important source of giant cloud condensation nuclei. Low temperature work using the environmental scanning electron microscope indicated that pollen grains do not act as deposition ice nuclei at temperatures warmer than - 15 deg. C.

  20. The quark condensate in a nuclear environment

    Energy Technology Data Exchange (ETDEWEB)

    Weise, W. [Regensburg Univ. (Germany). Inst. of Theoretical Physics

    1995-12-31

    A summary and survey on the change of the chiral condensate in dense (and hot) matter is presented. Implications for nuclear physics and relativistic heavy ion collisions are discussed, such as the strong Dirac scalar mean field that results from the density dependence of , and possible consequences for decreasing hadron masses in matter. (author). 22 refs., 4 figs.

  1. Condensation energy of the superconducting bilayer cuprates

    Indian Academy of Sciences (India)

    May & June 2002 physics pp. 861–866. Condensation energy of the superconducting bilayer cuprates. GOVIND1, AJAY2 and S K JOSHI1,3,∗. 1Theory Group, National Physical Laboratory, Dr. K.S. ... 2Department of Physics, G.B. Pant University of Agriculture and Technology, ..... [1] B Batlogg, Physics Today 44, 45 (1991).

  2. Cloud condensation nuclei from biomass burning

    International Nuclear Information System (INIS)

    Rogers, C.F.; Hudson, J.G.; Zielinska, B.; Tanner, R.L.; Hallett, J.; Watson, J.G.

    1991-01-01

    In this work, the authors have analyzed biomass and crude oil smoke samples for ionic and organic species. The cloud condensation nuclei activities of the smoke particles are discussed in terms of the measured chemical compositions of the smoke samples. The implications of biomass burning to global climatic change are discussed

  3. Free convective condensation in a vertical enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Fox, R.J.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States); Corradini, M.L.; Pernsteiner, A.P. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    Free convective condensation in a vertical enclosure was studied numerically and the results were compared with experiments. In both the numerical and experimental investigations, mist formation was observed to occur near the cooling wall, with significant droplet concentrations in the bulk. Large recirculation cells near the end of the condensing section were generated as the heavy noncondensing gas collecting near the cooling wall was accelerated downward. Near the top of the enclosure the recirculation cells became weaker and smaller than those below, ultimately disappearing near the top of the condenser. In the experiment the mist density was seen to be highest near the wall and at the bottom of the condensing section, whereas the numerical model predicted a much more uniform distribution. The model used to describe the formation of mist was based on a Modified Critical Saturation Model (MCSM), which allows mist to be generated once the vapor pressure exceeds a critical value. Equilibrium, nonequilibrium, and MCSM calculations were preformed, showing the experimental results to lie somewhere in between the equilibrium and nonequilibrium predictions of the numerical model. A single adjustable constant (indicating the degree to which equilibrium is achieved) is used in the model in order to match the experimental results.

  4. Mathematical modelling of dropwise condensation on textured ...

    Indian Academy of Sciences (India)

    Abstract. Vapor-to-liquid phase change in the form of discrete drops on or under- neath a substrate is called dropwise condensation. The process is hierarchical in the sense that it occurs over a wide range of length and timescales. As the associated heat transfer coefficient is much higher than the film and mixed mode of ...

  5. Fractional condensation of biomass pyrolysis vapors

    NARCIS (Netherlands)

    Westerhof, Roel Johannes Maria; Brilman, Derk Willem Frederik; Garcia Perez, M.; Wang, Zhouhong; Oudenhoven, Stijn; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.

    2011-01-01

    In this paper, we have investigated the possibilities to steer the composition and, thus, the quality of pyrolysis liquids by the reactor temperature and the pyrolysis vapor condenser temperature. Pine wood was pyrolyzed in a 1 kg/h fluidized-bed pyrolysis reactor operated at 330 or 480 °C. The

  6. Production of clean gasoline from the condensate

    Directory of Open Access Journals (Sweden)

    Noureddin Bentahar

    2013-12-01

    Full Text Available The locally available Algerian bentonite is explored to prepare catalysts for the isomerization of the light fractions of Algerian condensate to produce high quality gasoline of high octane number. Satisfying results are obtained which render these catalysts applicable for a large scale production.

  7. Scalar Condensation of Holographic Superconductors using ...

    Indian Academy of Sciences (India)

    2016-01-27

    Landau action with the -quartic term |Ψ|4. Our results show that -term plays a role in the scalar condensation. It is found that the system displays two kinds of critical temperatures. One is independent of . But the other increases ...

  8. Thermal condensation mode in a dusty plasma

    Indian Academy of Sciences (India)

    Abstract. In the present work, the radiative condensation instability is investigated in the presence of dust charge fluctuations. We find that the charge variability of the grain reduces the growth rate of radiative mode only for fluctuation wavelength smaller or of the order of the Debye length and this reduction is not very large.

  9. optimal evaporating and condensing temperatures of organic

    African Journals Online (AJOL)

    user

    36, No. 1, January, 2017 111. The heat input to the ORCplants is dependent on a wide range of heat sources ‒ namely waste heat from the condenser of a conventional or a nuclear power plant, waste heat from industrial processes, solar radiation, and geothermal energy. The solar power plant has a well-.

  10. Factorised steady states and condensation transitions in ...

    Indian Academy of Sciences (India)

    I will then consider a more general class of mass trans- port models, encompassing continuous mass variables and discrete time updating, and present a necessary and sufficient condition for the steady state to factorise. The prop- erty of factorisation again allows an analysis of the condensation transitions which may occur.

  11. CONVECTION IN CONDENSIBLE-RICH ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Ding, F. [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States); Pierrehumbert, R. T., E-mail: fding@uchicago.edu [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)

    2016-05-01

    Condensible substances are nearly ubiquitous in planetary atmospheres. For the most familiar case—water vapor in Earth’s present climate—the condensible gas is dilute, in the sense that its concentration is everywhere small relative to the noncondensible background gases. A wide variety of important planetary climate problems involve nondilute condensible substances. These include planets near or undergoing a water vapor runaway and planets near the outer edge of the conventional habitable zone, for which CO{sub 2} is the condensible. Standard representations of convection in climate models rely on several approximations appropriate only to the dilute limit, while nondilute convection differs in fundamental ways from dilute convection. In this paper, a simple parameterization of convection valid in the nondilute as well as dilute limits is derived and used to discuss the basic character of nondilute convection. The energy conservation properties of the scheme are discussed in detail and are verified in radiative-convective simulations. As a further illustration of the behavior of the scheme, results for a runaway greenhouse atmosphere for both steady instellation and seasonally varying instellation corresponding to a highly eccentric orbit are presented. The latter case illustrates that the high thermal inertia associated with latent heat in nondilute atmospheres can damp out the effects of even extreme seasonal forcing.

  12. Tunneling of trapped-atom Bose condensates

    Indian Academy of Sciences (India)

    Abstract. We obtain the dynamics in number and phase difference, for Bose condensates that tun- nel between two wells of a double-well atomic trap, using the (nonlinear) Gross–Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamil- tonian corresponds to that ...

  13. Condensate formation in a Bose gas

    NARCIS (Netherlands)

    Stoof, H.T.C.

    1995-01-01

    Using magnetically trapped atomic hydrogen as an example, we investigate the prospects of achieving Bose-Einstein condensation in a dilute Bose gas. We show that, if gas is quenched sufficiently far into the critical region of the phase transition, the typical time scale for the nucleation of the

  14. A transport-based condensed history algorithm

    International Nuclear Information System (INIS)

    Tolar, D. R. Jr.

    1999-01-01

    Condensed history algorithms are approximate electron transport Monte Carlo methods in which the cumulative effects of multiple collisions are modeled in a single step of (user-specified) path length s 0 . This path length is the distance each Monte Carlo electron travels between collisions. Current condensed history techniques utilize a splitting routine over the range 0 le s le s 0 . For example, the PEnELOPE method splits each step into two substeps; one with length ξs 0 and one with length (1 minusξ)s 0 , where ξ is a random number from 0 0 is fixed (not sampled from an exponential distribution), conventional condensed history schemes are not transport processes. Here the authors describe a new condensed history algorithm that is a transport process. The method simulates a transport equation that approximates the exact Boltzmann equation. The new transport equation has a larger mean free path than, and preserves two angular moments of, the Boltzmann equation. Thus, the new process is solved more efficiently by Monte Carlo, and it conserves both particles and scattering power

  15. ISOSPIN BREAKING AND THE CHIRAL CONDENSATE.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ, M.

    2005-07-25

    With two degenerate quarks, the chiral condensate exhibits a jump as the quark masses pass through zero. I discuss how this single transition splits into two Ising like transitions when the quarks are made non-degenerate. The order parameter is the expectation of the neutral pion field. The transitions represent long distance coherent phenomena occurring without the Dirac operator having vanishingly small eigenvalues.

  16. Orientifold Planar Equivalence: The Chiral Condensate

    DEFF Research Database (Denmark)

    Armoni, Adi; Lucini, Biagio; Patella, Agostino

    2008-01-01

    ) representation and $N_f$ flavours of Majorana fermions in the adjoint representation have the same large $N$ value for any value of the mass of the (degenerate) fermions. Assuming the invariance of the theory under charge conjugation, we prove this statement on the lattice for staggered quenched condensates...

  17. PECVD silicon nitride diaphragms for condenser microphones

    NARCIS (Netherlands)

    Scheeper, P.R.; Scheeper, P.R.; Voorthuyzen, J.A.; Voorthuyzen, J.A.; Bergveld, Piet

    1991-01-01

    The application of plasma-enhanced chemical vapour deposited (PECVD) silicon nitride as a diaphragm material for condenser microphones has been investigated. By means of adjusting the SiH4/NH3 gas-flow composition, silicon-rich silicon nitride films have been obtained with a relatively low tensile

  18. Connections between quantum chromodynamics and condensed ...

    Indian Academy of Sciences (India)

    Recently some of the analyses that originated in condensed matter physics have found applications in QCD. Using examples we discuss some of the connections between the two fields and show how progress can be made by exploiting this connection. Some of the challenges that remain in the two fields are quite similar.

  19. Tachyon condensation and black hole entropy.

    Science.gov (United States)

    Dabholkar, Atish

    2002-03-04

    String propagation on a cone with deficit angle 2pi(1-1 / N) is considered for the purpose of computing the entropy of a large mass black hole. The entropy computed using the recent results on condensation of twisted-sector tachyons in this theory is found to be in precise agreement with the Bekenstein-Hawking entropy.

  20. Tunneling of trapped-atom Bose condensates

    Indian Academy of Sciences (India)

    We obtain the dynamics in number and phase difference, for Bose condensates that tunnel between two wells of a double-well atomic trap, using the (nonlinear) Gross–Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamiltonian corresponds to that of a ...

  1. Condensation in a two-phase pool

    International Nuclear Information System (INIS)

    Duffey, R.B.; Hughes, E.D.

    1991-01-01

    We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases

  2. Vast Antimatter Regions and Scalar Condensate Baryogenesis

    OpenAIRE

    Kirilova, D P; Panayotova, M P; Valchanov, T

    2002-01-01

    The possibility of natural and abundant creation of antimatter in the Universe in a SUSY-baryogenesis model with a scalar field condensate is described. This scenario predicts vast quantities of antimatter, corresponding to galaxy and galaxy cluster scales today, separated from the matter ones by baryonically empty voids. Theoretical and observational constraints on such antimatter regions are discussed.

  3. Activity, purification, and analysis of condensed tannins

    Science.gov (United States)

    As a class of plant polyphenolic compounds contained in some forages (i.e., sanfoin, big trefoil, birdfoot trefoil), condensed tannins (CTs), also referred to as proanthocyanidins (PAs), exhibit a variety of biological effects on ruminants and on the dairy farm nitrogen cycle. Interest in CTs stems ...

  4. Condensed matter studies by nuclear methods

    International Nuclear Information System (INIS)

    Krolas, K.; Tomala, K.

    1988-01-01

    The separate abstract was prepared for 1 of the papers in this volume. The remaining 13 papers dealing with the use but not with advances in the use of nuclear methods in studies of condensed matter, were considered outside the subject scope of INIS. (M.F.W.)

  5. Fundamentals of neutron scattering by condensed matter

    Energy Technology Data Exchange (ETDEWEB)

    Scherm, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1996-12-31

    The purpose of this introductory lecture is to give the basic facts about the scattering of neutrons by condensed matter. This lecture is restricted to nuclear scattering, whereas magnetic scattering will be dealt with in an other course. Most of the formalism, however, can also be easily extended to magnetic scattering. (author) 17 figs., 3 tabs., 10 refs.

  6. A simple analytic solution for Tachyon condensation

    Czech Academy of Sciences Publication Activity Database

    Erler, T.; Schnabl, Martin

    -, č. 10 (2009), 066/1-066/35 ISSN 1126-6708 Grant - others:EUROHORC and ESF(XE) EYI/07/E010 Institutional research plan: CEZ:AV0Z10100502 Keywords : string field theory * Tachyon condensation Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 6.019, year: 2009 http://arxiv.org/abs/0906.0979

  7. Spermine Condenses DNA, but Not RNA Duplexes

    Energy Technology Data Exchange (ETDEWEB)

    Katz, Andrea M.; Tolokh, Igor S.; Pabit, Suzette A.; Baker, Nathan; Onufriev, Alexey V.; Pollack, Lois

    2017-01-01

    Interactions between the polyamine spermine and nucleic acids drive important cellular processes. Spermine condenses DNA, and some RNAs such as poly(rA):poly(rU). A large fraction of the spermine present in cells is bound to RNA, but apparently does not condense it. Here, we study the effect of spermine binding to short duplex RNA and DNA and compare our findings with predictions of molecular dynamics simulations. When small numbers of spermine are introduced, RNA with a designed sequence, containing a mixture of 14 GC pairs and 11 AU pairs, resists condensation relative to DNA of an equivalent sequence or to 25 base pair poly(rA):poly(rU) RNA. Comparison of wide-angle x-ray scattering profiles with simulation suggests that spermine is sequestered deep within the major groove of mixed sequence RNA, preventing condensation by limiting opportunities to bridge to other molecules as well as stabilizing the RNA by locking it into a particular conformation. In contrast, for DNA, simulations suggest that spermine binds external to the duplex, offering opportunities for intermolecular interaction. The goal of this study is to explain how RNA can remain soluble, and available for interaction with other molecules in the cell, despite the presence of spermine at concentrations high enough to precipitate DNA.

  8. Condensation enhancement by means of electrohydrodynamic techniques

    Directory of Open Access Journals (Sweden)

    Butrymowicz Dariusz

    2014-12-01

    Full Text Available Short state-of-the-art on the enhancement of condensation heat transfer techniques by means of condensate drainage is presented in this paper. The electrohydrodynamic (EHD technique is suitable for dielectric media used in refrigeration, organic Rankine cycles and heat pump devices. The electric field is commonly generated in the case of horizontal tubes by means of a rod-type electrode or mesh electrodes. Authors proposed two geometries in the presented own experimental investigations. The first one was an electrode placed just beneath the tube bottom and the second one consisted of a horizontal finned tube with a double electrode placed beneath the tube. The experimental investigations of these two configurations for condensation of refrigerant R-123 have been accomplished. The obtained results confirmed that the application of the EHD technique for the investigated tube and electrode arrangement caused significant increase in heat transfer coefficient. The condensation enhancement depends both on the geometry of the electrode system and on the applied voltage.

  9. Counterion condensation and release in micellar solutions

    Science.gov (United States)

    Hsiao, Chin Chieh; Wang, Tzu-Yu; Tsao, Heng-Kwong

    2005-04-01

    Counterion condensation and release in micellar solutions are investigated by direct measurement of counterion concentration with ion-selective electrode. Monte Carlo simulations based on the cell model are also performed to analyze the experimental results. The degree of counterion condensation is indicated by the concentration ratio of counterions in the bulk to the total ionic surfactant added, α⩽1. The ionic surfactant is completely dissociated below the critical micelle concentration (cmc). However, as cmc is exceeded, the free counterion ratio α declines with increasing the surfactant concentration and approaches an asymptotic value owing to counterion condensation to the surface of the highly charged micelles. Micelle formation leads to much stronger electrostatic attraction between the counterion and the highly charged sphere in comparison to the attraction of single surfactant ion with its counterion. A simple model is developed to obtain the true degree of ionization, which agrees with our Monte Carlo results. Upon addition of neutral polymer or monovalent salts, some of the surfactant counterions are released to the bulk. The former is due to the decrease of the intrinsic charge (smaller aggregation number) and the degree of ionization is increased. The latter is attributed to competitive counterion condensation, which follows the Hefmeister series. This consequence indicates that the specific ion effect plays an important role next to the electrostatic attraction.

  10. Condensed tannins. Structure of the "phenolic scids"

    Science.gov (United States)

    Peter E. Laks; Richard W. Hemingway

    1987-01-01

    Conifer bark-derived condensed tannins can be used in formulating adhesives. Under some extraction conditions and during normal adhesive formulation, the tannin is exposed to strongly alkaline conditions. Alkaline rearrangement results in partial or total rearrangement of tannins of the procyanidin class to "phenolic acids" which have less phloroglucinol...

  11. Scalar Condensation of Holographic Superconductors using ...

    Indian Academy of Sciences (India)

    Abstract. We study holographic superconductors analytically by using the Ginzburg–Landau action with the γ-quartic term | |4. Our results show that γ-term plays a role in the scalar condensation. It is found that the system displays two kinds of critical temperatures. One is independent of γ. But the other increases with ...

  12. Homogeneous cosmologies as group field theory condensates

    Energy Technology Data Exchange (ETDEWEB)

    Gielen, Steffen [Perimeter Institute for Theoretical Physics,31 Caroline St. N., Waterloo, Ontario N2L 2Y5 (Canada); Oriti, Daniele; Sindoni, Lorenzo [Max Planck Institute for Gravitational Physics (Albert Einstein Institute),Am Mühlenberg 1, 14476 Golm (Germany)

    2014-06-03

    We give a general procedure, in the group field theory (GFT) formalism for quantum gravity, for constructing states that describe macroscopic, spatially homogeneous universes. These states are close to coherent (condensate) states used in the description of Bose-Einstein condensates. The condition on such states to be (approximate) solutions to the quantum equations of motion of GFT is used to extract an effective dynamics for homogeneous cosmologies directly from the underlying quantum theory. The resulting description in general gives nonlinear and nonlocal equations for the ‘condensate wavefunction’ which are analogous to the Gross-Pitaevskii equation in Bose-Einstein condensates. We show the general form of the effective equations for current quantum gravity models, as well as some concrete examples. We identify conditions under which the dynamics becomes linear, admitting an interpretation as a quantum-cosmological Wheeler-DeWitt equation, and give its semiclassical (WKB) approximation in the case of a kinetic term that includes a Laplace-Beltrami operator. For isotropic states, this approximation reproduces the classical Friedmann equation in vacuum with positive spatial curvature. We show how the formalism can be consistently extended from Riemannian signature to Lorentzian signature models, and discuss the addition of matter fields, obtaining the correct coupling of a massless scalar in the Friedmann equation from the most natural extension of the GFT action. We also outline the procedure for extending our condensate states to include cosmological perturbations. Our results form the basis of a general programme for extracting effective cosmological dynamics directly from a microscopic non-perturbative theory of quantum gravity.

  13. Gravitationally Driven Wicking for Enhanced Condensation Heat Transfer.

    Science.gov (United States)

    Preston, Daniel J; Wilke, Kyle L; Lu, Zhengmao; Cruz, Samuel S; Zhao, Yajing; Becerra, Laura L; Wang, Evelyn N

    2018-04-05

    Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Filmwise condensation is prevalent in typical industrial-scale systems, where the condensed fluid forms a thin liquid film due to the high surface energy associated with many industrial materials. Conversely, dropwise condensation, where the condensate forms discrete liquid droplets which grow, coalesce, and shed, results in an improvement in heat transfer performance of an order of magnitude compared to filmwise condensation. However, current state-of-the-art dropwise technology relies on functional hydrophobic coatings, for example, long chain fatty acids or polymers, which are often not robust and therefore undesirable in industrial conditions. In addition, low surface tension fluid condensates, such as hydrocarbons, pose a unique challenge because common hydrophobic condenser coatings used to shed water (with a surface tension of 73 mN/m) often do not repel fluids with lower surface tensions (heat transfer using gravitationally driven flow through a porous metal wick, which takes advantage of the condensate's affinity to wet the surface and also eliminates the need for condensate-phobic coatings. The condensate-filled wick has a lower thermal resistance than the fluid film observed during filmwise condensation, resulting in an improved heat transfer coefficient of up to an order of magnitude and comparable to that observed during dropwise condensation. The improved heat transfer realized by this design presents the opportunity for significant energy savings in natural gas processing, thermal management, heating and cooling, and power generation.

  14. Condensation shocks in high momentum two-phase flows in condensing injectors

    International Nuclear Information System (INIS)

    Anand, G.; Christensen, R.N.

    1993-01-01

    This study presents a phenomenological and mathematical model of condensation shocks in high momentum two-phase flows in condensing injectors. The characteristics of the shock were related to the mode of vapor bubble collapse. Using cavitation terminology, the bubble collapse can be classified as inertially controlled or thermally controlled. Inertial bubble collapse occurs rapidly whereas, a thermally controlled collapse results in a significantly longer collapse time. The interdependence between the bubble collapse mode and the momentum and pressure of the flow, was analyzed in this study. For low-temperature-high-velocity flows a steep pressure rise with complete condensation was obtained. For a high-temperature-low velocity flow with noncondensables, low pressure recovery with incomplete condensation was observed. These trends are in agreement with previous experimental observations

  15. A Test Condenser to Measure Condensate Inundation Effects in a Tube Bundle.

    Science.gov (United States)

    1981-03-01

    total weight of a steam propulsion plant by reducing the size and amount of material required. Depending upon the condenser material , initial and...water heater ( feedwater tank) (not required) 4. #4 - Condensate pumps 5 #5 - Boiler (not required) 6. #6 - Cooling tower 7. #7 - Cooling water pump...coefficient for a column of N tubes (W/m 2 -OK) - Heat transfer coefficient calculated from the hNu Nusselt equation (W/m2-°K) h I - Experimentally determined

  16. Gênese e Morfologia de Estruturas Sedimentares Induzidas por Atividade Microbiana (MISS em Sedimentos da Lagoa Vermelha (Região dos Lagos – Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Lorena da Fonseca Sampaio

    2015-01-01

    Full Text Available dimentos. O desconhecimento dos critérios que permitem a identificação dessas estruturas no registro geológico dificulta seu amplo reconhecimento, sendo por vezes confundidas com estruturas físicas de deposição e erosão. Historicamente, a Lagoa Vermelha é reconhecida por estudos biológicos, mineralógicos, geoquímicos e isotópicos, relacionados a estromatólitos e esteiras microbianas. Contudo, as estruturas sedimentares induzidas por atividade microbiana nunca foram objeto de estudo. Dessa forma, o presente estudo objetiva a análise e caracterização das MISS que ocorrem nos sedimentos da Lagoa Vermelha, reconhecendo os principais fatores biossedimentológicos envolvidos em sua gênese. Foi possível a distinção de onze estruturas resultantes dos processos de crescimento microbial (estrutura de nivelamento laminada, bioestabilização (gretas de dessecamento; mat curls; mat chips, metabolismo da esteira (biolaminito; estromatólito; estromatólito biscuit; nódulo trombolítico, binding, baffling e trapping e estruturas resultantes de mais de uma atividade microbial interagindo com a dinâmica sedimentar (wrinkles; estrutura de descolamento; petees. Análises petrográficas permitiram o reconhecimento dessas estruturas em microescala e de outras feições organossedimentares associadas à atividade microbial. Os resultados gerados permitem a melhor compreensão da interação entre processos microbiais e fatores ambientais atuantes na formação de estruturas sedimentares induzidas por micro-organismos, bem como, auxiliam seu reconhecimento no registro geológico em sucessões continentais e marinhas.

  17. Bubbler condenser related research work. Present situation

    International Nuclear Information System (INIS)

    2001-02-01

    Intensive discussions within the OECD Support Group on 'VVER-440 Bubbler Condenser Containment Research Work' between 1991 and 1994 demonstrated the need for supplementary research work to achieve an adequate level of basic knowledge. In 1994, the European Commission (EC) asked for a specific 'VVER-440/213 Bubble Condenser Qualification Feasibility Study', which was finished early in 1996, confirming the need for additional research in this field. The Feasibility study formed the basis for the Bubble Condenser Experimental Qualification Project (BCEQ) with two separate experimental activities to be executed within the frame of the PHARE/TACIS 2.13/95 project of the European Commission. A first activity served to study the thermal-hydraulic phenomena and the associated structure dynamic interactions. This part of the project was performed at EREC, in Elektrogorsk, Russia. The design of the test facility was based on the prototypical bubbler condenser configuration for the Hungarian Paks nuclear power plant. A second activity addressed the structural integrity of certain components of the bubbler condenser steel structures under DBA-typical conditions. This part of the project was performed at VUEZ, in Levice, Slovak Republic. The design of the components of this facility was based on the structural properties of the Dukovany and/or Bohunice nuclear power plants. A third component of the BCEQ project was specified later asking for analytical studies, which should be supported by a number of small-scale separate effects tests to be performed at SVUSS, in Bechovice, Czech Republic. The main experimental and analytical results of the BCEQ test campaigns have been presented and discussed within the frame of the 4. meeting of the Technical Advisory Committee to the BCEQ (Bubble Condenser Experimental Qualification) Project in Brussels in December 1999 and on occasion of the 11. OECD Support Group Meeting in Berlin in April 2000. The discussions had evidenced several

  18. Condensation: Passenger Not Driver in Atmospheric Thermodynamics

    Directory of Open Access Journals (Sweden)

    Jack Denur

    2016-11-01

    Full Text Available The second law of thermodynamics states that processes yielding work or at least capable of yielding work are thermodynamically spontaneous, and that those costing work are thermodynamically nonspontaneous. Whether a process yields or costs heat is irrelevant. Condensation of water vapor yields work and hence is thermodynamically spontaneous only in a supersaturated atmosphere; in an unsaturated atmosphere it costs work and hence is thermodynamically nonspontaneous. Far more of Earth’s atmosphere is unsaturated than supersaturated; based on this alone evaporation is far more often work-yielding and hence thermodynamically spontaneous than condensation in Earth’s atmosphere—despite condensation always yielding heat and evaporation always costing heat. Furthermore, establishment of the unstable or at best metastable condition of supersaturation, and its maintenance in the face of condensation that would wipe it out, is always work-costing and hence thermodynamically nonspontaneous in Earth’s atmosphere or anywhere else. The work required to enable supersaturation is most usually provided at the expense of temperature differences that enable cooling to below the dew point. In the case of most interest to us, convective weather systems and storms, it is provided at the expense of vertical temperature gradients exceeding the moist adiabatic. Thus, ultimately, condensation is a work-costing and hence thermodynamically nonspontaneous process even in supersaturated regions of Earth’s or any other atmosphere. While heat engines in general can in principle extract all of the work represented by any temperature difference until it is totally neutralized to isothermality, convective weather systems and storms in particular cannot. They can extract only the work represented by partial neutralization of super-moist-adiabatic lapse rates to moist-adiabaticity. Super-moist-adiabatic lapse rates are required to enable convection of saturated air

  19. Confinement and magnetic condensation for N → infinity

    International Nuclear Information System (INIS)

    Olesen, P.

    1982-01-01

    The author discusses why magnetic condensation is necessary for confinement. Using the Makeenko-Migdal equation he then indicates that for N → infinity (in SU(N)) one has a condensate of magnetic strings in the QCD vacuum. (Auth.)

  20. Refrigeration. Heat Transfer. Part I: Evaporators and Condensers

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation.......The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation....

  1. Condensation of water vapor in the gravitational field

    Energy Technology Data Exchange (ETDEWEB)

    Gorshkov, V. G.; Makarieva, A. M.; Nefiodov, A. V., E-mail: anef@thd.pnpi.spb.ru [Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)

    2012-10-15

    Physical peculiarities of water vapor condensation under conditions of hydrostatic equilibrium are considered. The power of stationary dynamic air fluxes and the vertical temperature distribution caused by condensation on large horizontal scales are estimated.

  2. Theoretical Investigations of Trapped Interacting Bose-Einstein Condensates

    National Research Council Canada - National Science Library

    You, Li

    1999-01-01

    .... Primary topics being addressed are: (1) To understand the properties of atomic Bose-Einstein condensates, in particular, the low energy excitations, dynamics of Bose-Einstein condensation, vortex states creation and detection. (2...

  3. NAMMA CVI CLOUD CONDENSED WATER CONTENT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — In the NAMMA CVI Cloud Condensed Water Content dataset the counterflow virtual impactor (CVI) was used to measure condensed water content (liquid water or ice in...

  4. Automação e integração CAD/CAE no projeto de estruturas metalicas, utilizando perfis tubulares

    OpenAIRE

    Mauricio Guilherme Quilez Souza

    2006-01-01

    Resumo: Este trabalho tem como objetivo o desenvolvimento de códigos de computador que têm a finalidade de automatizar as etapas principais de um projeto de estruturas metálicas através das linguagens AutoLISP e Delphi5. Os projetos de estruturas metálicas em estudo são os de coberturas com treliças planas constituídas de barras com perfis tubulares laminados sem costuras e seus contraventamentos. Estes perfis tubulares, ainda pouco utilizados em estruturas planas no Brasil, vêm sendo dissemi...

  5. Efeitos do strike das estruturas geológicas de duas dimensões nas pseudos-seções de IP resistividade

    OpenAIRE

    GUIMARÃES, Paulo Buarque de Macedo

    1983-01-01

    Os levantamentos de IP-resistividade efetuados na Serra dos Carajás não foram executados ortogonalmente às estruturas geológicas, pois utilizaram linhas anteriormente abertas pelas equipes de geoquímica. Este fato motivou este estudo teórico da influência da direção das linhas de medidas de IP-resistividade em relação ao "strike" da estrutura. Foi usado o programa de elementos finitos de Rijo (1977), desenvolvido para levantamentos perpendiculares às estruturas com as adaptações necessárias. ...

  6. Spin-Orbit Coupled Bose-Einstein Condensates

    Science.gov (United States)

    2016-11-03

    Spin-Orbit Coupled Bose- Einstein Condensates This ARO research proposal entitled "SPIN-ORBIT COUPLED BOSE- EINSTEIN CONDENSATES" (SOBECs) explored...Administration 3112 Lee Building 7809 Regents Drive College Park, MD 20742 -5141 ABSTRACT Final Report: Spin-Orbit Coupled Bose- Einstein Condensates...Report Title This ARO research proposal entitled "SPIN-ORBIT COUPLED BOSE- EINSTEIN CONDENSATES" (SOBECs) explored properties of the fundamentally new

  7. Estrutura de capital: o papel das fontes de financiamento nas quais companhias abertas brasileiras se baseiam

    Directory of Open Access Journals (Sweden)

    Wilson Tarantin Junior

    2015-01-01

    Full Text Available ResumoEste estudo avaliou a estrutura de capital de companhias abertas brasileiras, no período de 2005 a 2012, verificando o papel das fontes de financiamento nas quais tais companhias se baseiam. Para tanto, foi avaliada a proporção das dívidas em 3 fontes distintas: as instituições financeiras, o mercado de capitais e as fontes com taxas de juros subsidiadas, estas últimas representando um fator institucional da economia brasileira. Foi utilizada uma amostra de 95 empresas, dentre as 150 maiores empresas com ações negociadas na Bolsa de Valores, Mercadorias e Futuros de São Paulo (BM&FBOVESPA. Por meio de modelos com dados em painel, os resultados mostram que as fontes de financiamento impactam a formação da estrutura de capital das empresas, exercendo influência tanto na alavancagem quanto na maturidade das dívidas. Em relação à alavancagem, empresas que têm maior proporção de seus recursos captados no mercado de capitais são mais alavancadas. O mesmo não acontece com as empresas que têm maior proporção de recursos subsidiados. Em relação à maturidade das dívidas, recursos de diferentes maturidades são captados em diferentes fontes: os recursos de menores maturidades são captados em instituições financeiras e os recursos de maiores maturidades são captados no mercado de capitais e nas fontes com taxas de juros subsidiadas - leia-se Banco Nacional de Desenvolvimento Econômico e Social (BNDES. Comparando-se os recursos do mercado de capitais com os recursos subsidiados, verifica-se que os primeiros têm maior maturidade. Tal resultado pode ser justificado em virtude do crescimento do mercado de capitais brasileiro nos últimos anos, a partir de 2009, de modo que as companhias estão se baseando no mercado de capitais para seus financiamentos de maior maturidade e nos recursos subsidiados, do BNDES, para seus financiamentos de maturidades intermediárias.

  8. ESTRUTURA DE MADEIRA PARA COBERTURA DE AVIÁRIOS NO ESTADO DA PARAÍBA

    Directory of Open Access Journals (Sweden)

    Marluce Araújo de Azevedo

    1999-12-01

    Full Text Available RESUMO Este trabalho apresenta o cálculo estrutural de cobertura com treliça do tipo "Howe", utilizando-se as madeiras roxinho ( Peltogyne sp., Leguminosae e maçaranduba ( Manilkara sp., Sapotaceae disponíveis no mercado de Campina Grande, Paraíba, e visa a execução de projeto de estrutura para aviário, considerando-se as recomendações da norma técnica brasileira NBR 7190/1997 e duas situações de galpão: aviário com oitões em alvenaria e ventilação artificial e aviário com oitões abertos e túnel de vento no sentido longitudinal, ambas com 12 m de vão e 125 m de comprimento. Devido à globalização da economia, a escolha do projeto arquitetônico se deu em função do tipo de exploração, dos parâmetros de conforto térmico, manejo, custo e uso racional da madeira. Os resultados obtidos indicam que a estrutura formada por treliça composta de banzos com seções transversais simples de 7,5 x 12,5 cm, diagonais com seções transversais simples de 7,5 x 10,0 cm e montantes com seções transversais duplas de 3,5 x 12,5 cm, terças com seções transversais de 7,5 x 15 cm, contraventamento tendo seção transversal de 7,5 x 12,5 cm e espaçamento entre treliças de 2,72 m, apresenta o menor consumo de madeira por metro quadrado de área coberta e, conseqüentemente, o menor custo.

  9. Film condensation on non-isothermal vertical plates

    NARCIS (Netherlands)

    Brouwers, Jos

    1989-01-01

    An analytical study is presented of the condensation of a pure saturated vapour on a cooled channel plate, including the interaction between the cooling liquid, the condensate and the vapour. The governing equations of co-, counter- and cross-current condensation are derived, set dimensionless and

  10. 21 CFR 131.120 - Sweetened condensed milk.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Sweetened condensed milk. 131.120 Section 131.120... FOR HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.120 Sweetened condensed milk. (a) Description. Sweetened condensed milk is the food obtained by partial removal...

  11. Collapsing dynamics of attractive Bose-Einstein condensates

    DEFF Research Database (Denmark)

    Bergé, L.; Juul Rasmussen, J.

    2002-01-01

    The self-similar collapse of 3D and quasi-2D atom condensates with negative scattering length is examined. 3D condensates are shown to blow up following the scenario of weak collapse, for which 3-body recombination weakly dissipates the atoms. In contrast, 2D condensates undergo a strong collapse...

  12. CFD modelling of condensers for freeze-drying processes

    Indian Academy of Sciences (India)

    ... the condenser, in order to evaluate condenser efficiency and gain deeper insights of the process to be used for the improvement of its design. Both a complete laboratory-scale freeze-drying apparatus and an industrial-scale condenser have been investigated in this work, modelling the process of water vapour deposition.

  13. 40 CFR 63.447 - Clean condensate alternative.

    Science.gov (United States)

    2010-07-01

    ... concentrations in the pulping process water used within the clean condensate alternative affected source. (c... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Clean condensate alternative. 63.447... Standards for Hazardous Air Pollutants from the Pulp and Paper Industry § 63.447 Clean condensate...

  14. Condensate storage vessel cleaning device for nuclear power plant

    International Nuclear Information System (INIS)

    Nagase, Tatsuo; Yamamoto, Osamu

    1998-01-01

    An ordinary condensate storage vessel which is a water source of an ordinary water absorbing load and an emergency condensate storage vessel which is a water source such as of an emergency reactor core cooling facility are disposed separately and connected by a water feeding line, and there is disposed a returning line connecting a filtering desalting device of a fuel pool cleaning facility for cooling and cleaning spent fuel pool water and the emergency condensate storage vessel, a suppression pool. When condensate stored in the emergency condensate storage vessel is cleaned by the filtering desalting device of the fuel pool cleaning facility and returned to the emergency condensate storage vessel by the returning line, the condensate can be cleaned periodically. In addition, condensate after purification is optionally supplied from the ordinary condensate storage vessel to the emergency condensate storage vessel to store water. Then, the emergency condensate storage vessel can be reduced in the size, and the construction cost for the ordinary condensate storage vessel can be reduced. (N.H.)

  15. Variability in condensed tannins and bitterness in spider plant ...

    African Journals Online (AJOL)

    Total phenolic compounds and condensed tannins were quantified in five genotypes. The amount of total phenolic compounds were not significant, but quite significant (P<0.001) for condensed tannins. Genotype CGSKGP had the highest (0.49 mg g-1) and twice as much condensed tannins as CGKEX and CGSKP.

  16. Formaldehyde condensation products of model phenols for conifer bark tannins

    Science.gov (United States)

    Richard W. Hemingway; Gerald W. McGraw

    1978-01-01

    Gel permeation chromatography of the condensation products of phenols and formaldehyde proved effective in understanding the reactions of condensed tannins with formaldehyde. Rates of condensation of phloroglucinols, resorcinols, catechols, (+)catechins, and (-)epicatechin were examined to determine if methylol-tannins from southern pine bark could be prepared as resin...

  17. Evaporation and Condensation Flows of a Vapor-Gas Mixture from or onto the Condensed Phase with an Internal Structure

    National Research Council Canada - National Science Library

    Onishi, Yoshimoto; Yamada, Ken

    2005-01-01

    Transient motions of a vapor-gas mixture due to the evaporation and condensation processes from or onto the plane condensed phase, with a temperature field as its internal structure, have been studied...

  18. Bose-Einstein condensation in microgravity.

    Science.gov (United States)

    van Zoest, T; Gaaloul, N; Singh, Y; Ahlers, H; Herr, W; Seidel, S T; Ertmer, W; Rasel, E; Eckart, M; Kajari, E; Arnold, S; Nandi, G; Schleich, W P; Walser, R; Vogel, A; Sengstock, K; Bongs, K; Lewoczko-Adamczyk, W; Schiemangk, M; Schuldt, T; Peters, A; Könemann, T; Müntinga, H; Lämmerzahl, C; Dittus, H; Steinmetz, T; Hänsch, T W; Reichel, J

    2010-06-18

    Albert Einstein's insight that it is impossible to distinguish a local experiment in a "freely falling elevator" from one in free space led to the development of the theory of general relativity. The wave nature of matter manifests itself in a striking way in Bose-Einstein condensates, where millions of atoms lose their identity and can be described by a single macroscopic wave function. We combine these two topics and report the preparation and observation of a Bose-Einstein condensate during free fall in a 146-meter-tall evacuated drop tower. During the expansion over 1 second, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter.

  19. Quantum monodromy in trapped Bose condensates

    International Nuclear Information System (INIS)

    Waalkens, H.

    2002-01-01

    Bose-Einstein condensation of ultra cold atoms is typically realized in magnetic traps which effectively lead to an axially symmetric harmonic potential. This letter shows that the spectrum of collective vibrational modes of a repulsive condensate in a prolate potential displays a defect known as quantum monodromy. The monodromy is analysed on the basis of the dynamics of quasiparticles. In terms of the quasiparticles the regime of collective modes or the so-called hydrodynamic regime is characterized through kinetic energies much smaller than the chemical potential. In this limit the classical dynamics of the quasiparticles is integrable. The monodromy is quantitatively described by a monodromy matrix that is calculated from classical actions. (authors)

  20. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  1. Hydrogen behavior in ice condenser containments

    Energy Technology Data Exchange (ETDEWEB)

    Lundstroem, P.; Hongisto, O. [Power Plant Lab., Helsinki (Finland); Theofanous, T.G. [Univ. of California, Santa Barbara, CA (United States)] [and others

    1995-09-01

    A new hydrogen management strategy is being developed for the Loviisa ice condenser containment. The strategy relies on containment-wide natural circulations that develop, once the ice condenser doors are forced open, to effectively produce a well-mixed behavior, and a correspondingly slow rise in hydrogen concentration. Levels can then be kept low by a distributed catalytic recombiner system, and (perhaps) an igniter system as a backup, while the associated energy releases can be effectively dissipated in the ice bed. Verification and fine-tuning of the approach is carried out experimentally in the VICTORIA facility and by associated scaling/modelling studies. VICTORIA represents an 1/15th scale model of the Loviisa containment, hydrogen is simulated by helium, and local concentration measurements are obtained by a newly developed instrument specifically for this purpose, called SPARTA. This paper is focused on experimental results from several key experiments that provide a first delineation of key behaviors.

  2. Faraday waves in Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Nicolin, Alexandru I.; Carretero-Gonzalez, R.; Kevrekidis, P. G.

    2007-01-01

    Motivated by recent experiments on Faraday waves in Bose-Einstein condensates we investigate both analytically and numerically the dynamics of cigar-shaped Bose-condensed gases subject to periodic modulation of the strength of the transverse confinement. We offer a fully analytical explanation of the observed parametric resonance, based on a Mathieu-type analysis of the non-polynomial Schroedinger equation. The theoretical prediction for the pattern periodicity versus the driving frequency is directly compared to the experimental data, yielding good qualitative and quantitative agreement between the two. These results are corroborated by direct numerical simulations of both the one-dimensional non-polynomial Schroedinger equation and of the fully three-dimensional Gross-Pitaevskii equation

  3. Condensation Mechanism of Hydrocarbon Field Formation.

    Science.gov (United States)

    Batalin, Oleg; Vafina, Nailya

    2017-08-31

    Petroleum geology explains how hydrocarbon fluids are generated, but there is a lack of understanding regarding how oil is expelled from source rocks and migrates to a reservoir. To clarify the process, the multi-layer Urengoy field in Western Siberia was investigated. Based on this example, we have identified an alternative mechanism of hydrocarbon field formation, in which oil and gas accumulations result from the phase separation of an upward hydrocarbon flow. There is evidence that the flow is generated by the gases released by secondary kerogen destruction. This study demonstrates that oil components are carried by the gas flow and that when the flow reaches a low-pressure zone, it condenses into a liquid with real oil properties. The transportation of oil components in the gas flow provides a natural explanation for the unresolved issues of petroleum geology concerning the migration process. The condensation mechanism can be considered as the main process of oil field formation.

  4. Development status of condensed cluster fusion theory

    International Nuclear Information System (INIS)

    Takahashi, Akito

    2015-01-01

    The condensed cluster fusion theory has been developed since 1989, under the view that dynamic ordering processes of confined transient clusters of D(H)-particles in catalytic surface sites, vacancies and global mesoscopic potential well of metal nanoparticles may induce simultaneous multi-body fusion reactions. One thorough answer is obtained for the condensation motion of clusters under platonic symmetry like 4D(H)/TSC, 6D(H)/RDC and 8D(H)/RDC and their fusion reaction rates. Theoretical analysis for initial dynamic clustering process on/in catalytic sites is still speculative and under searching a technique to combine the electron density functional method and the QM Langevin method. (author)

  5. Laser Processed Condensing Heat Exchanger Technology Development

    Science.gov (United States)

    Hansen, Scott; Wright, Sarah; Wallace, Sarah; Hamilton, Tanner; Dennis, Alexander; Zuhlke, Craig; Roth, Nick; Sanders, John

    2017-01-01

    The reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. The Laser Processed Condensing Heat Exchanger project aims to solve these problems through the use of femtosecond laser processed surfaces, which have unique wetting properties and potentially exhibit anti-microbial growth properties. These surfaces were investigated to identify if they would be suitable candidates for a replacement CHX surface. Among the areas researched in this project include microbial growth testing, siloxane flow testing in which laser processed surfaces were exposed to siloxanes in an air stream, and manufacturability.

  6. Performance characterization of isolation condenser of SBWR

    International Nuclear Information System (INIS)

    Khan, H.J.; Rohatgi, U.S.

    1992-01-01

    A systematic study of the performance of the Isolation Condenser (IC) for a conceptual design of SBWR is presented. The objective of the IC is to passively remove heat and control the pressure variation in the Reactor Pressure Vessel (RPV). According to the observed trends, the IC cooling capacity and condensate flow can independently influence the ultimate performance of the IC. The transient pressure profile for the IC reaches different equilibrium values for each of the cases analyzed. The absolute magnitude of these values are a function of the cooling capacity and flow rates. With appropriate control of the liquid flow loss coefficients, the performance of the IC can be well predicted. Due to the lack of useful data, this study is limited to the numerical simulation of the IC

  7. A superheated Bose-condensed gas

    Science.gov (United States)

    Gaunt, Alexander L.; Fletcher, Richard J.; Smith, Robert P.; Hadzibabic, Zoran

    2013-05-01

    Our understanding of various states of matter usually relies on the assumption of thermodynamic equilibrium. However, the transitions between different phases of matter can be strongly affected by non-equilibrium phenomena. Here we demonstrate and explain an example of non-equilibrium stalling of a continuous, second-order phase transition. We create a superheated atomic Bose gas, in which a Bose-Einstein condensate (BEC) persists above the equilibrium critical temperature, Tc, if its coupling to the surrounding thermal bath is reduced by tuning interatomic interactions. For vanishing interactions the BEC persists in the superheated regime for a minute. However, if strong interactions are suddenly turned on, it rapidly boils away. Our observations can be understood within a two-fluid picture, treating the condensed and thermal components of the gas as separate equilibrium systems with a tunable inter-component coupling. We experimentally reconstruct a non-equilibrium phase diagram of our gas, and theoretically reproduce its main features.

  8. A tumbling top-quark condensate model

    International Nuclear Information System (INIS)

    Martin, S.P.

    1992-01-01

    We propose a renormalizable model with no fundamental scalars which breaks itself in the manner of a ''tumbling'' gauge theory down to the standard model with a top-quark condensate. Because of anomaly cancellation requirements, this model contains two color sextet fermions (quixes), which are vector-like with respect to the standard model gauge group. The model also has a large number of pseudo-Nambu-Goldstone bosons, some of which can be light. The top-quark condensate is responsible for breaking the electroweak gauge symmetry and gives the top quark a large mass. We discuss the qualitative features and instructive shortcomings of the model in its present form. We also show that this model can be naturally embedded into an aesthetically pleasing model in which the standard model fermion appear symmetrically

  9. Essence of the Vacuum Quark Condensate

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Roberts, Craig D.; /Argonne, PHY /Peking U.; Shrock, Robert; /YITP, Stony Brook; Tandy, Peter C.; /Kent State U.

    2010-08-25

    We show that the chiral-limit vacuum quark condensate is qualitatively equivalent to the pseudoscalar meson leptonic decay constant in the sense that they are both obtained as the chiral-limit value of well-defined gauge-invariant hadron-to-vacuum transition amplitudes that possess a spectral representation in terms of the current-quark mass. Thus, whereas it might sometimes be convenient to imagine otherwise, neither is essentially a constant mass-scale that fills all spacetime. This means, in particular, that the quark condensate can be understood as a property of hadrons themselves, which is expressed, for example, in their Bethe-Salpeter or light-front wavefunctions.

  10. Kaon condensation and multi-strange matter

    Czech Academy of Sciences Publication Activity Database

    Gazda, Daniel; Friedman, E.; Gal, A.; Mareš, Jiří

    2010-01-01

    Roč. 835, 1-4 (2010), s. 287-294 ISSN 0375-9474. [10th International Conference on Hypernuclear and Strange Particle Physics. Tokai, 14.09.2009-18.09.2009] Institutional research plan: CEZ:AV0Z10480505 Keywords : K)over-bar deeply bound nuclear states * multi-(K)over-bar nuclei * kaon condensation Subject RIV: BE - Theoretical Physics Impact factor: 1.986, year: 2010

  11. Bouncing cosmologies from quantum gravity condensates

    Science.gov (United States)

    Oriti, Daniele; Sindoni, Lorenzo; Wilson-Ewing, Edward

    2017-02-01

    We show how the large-scale cosmological dynamics can be obtained from the hydrodynamics of isotropic group field theory condensate states in the Gross-Pitaevskii approximation. The correct Friedmann equations are recovered in the classical limit for some choices of the parameters in the action for the group field theory, and quantum gravity corrections arise in the high-curvature regime causing a bounce which generically resolves the big-bang and big-crunch singularities.

  12. Inflation induced by Gravitino Condensation in Supergravity

    CERN Document Server

    Ellis, John

    2013-01-01

    We discuss the emergence of an inflationary phase in supergravity with the super-Higgs effect due to dynamical spontaneous breaking of supersymmetry, in which the role of the inflaton is played by the gravitino condensate. Realistic models compatible with the Planck satellite CMB data are found in conformal supergravity scenarios with dynamical gravitino masses that are small compared to the Planck mass, as could be induced by a non-trivial vacuum expectation value of the dilaton superfield of appropriate magnitude.

  13. THE COLOUR GLASS CONDENSATE: AN INTRODUCTION

    International Nuclear Information System (INIS)

    Iancu, E.; Leonidov, A.; McLerran, L.

    2001-01-01

    In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory

  14. THE COLOUR GLASS CONDENSATE: AN INTRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    IANCU,E.; LEONIDOV,A.; MCLERRAN,L.

    2001-08-06

    In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory.

  15. Synthesis of double condensed cesium gallium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Chudinova, N.N.; Grunze, I.; Guzeeva, L.S.; Avaliani, M.A.

    1987-09-01

    By crystallization from melts of polyphosphoric acids there are obtained double condensed phosphates of cesium and gallium of the following compositions: Cs/sub 2/GaH/sub 3/(P/sub 2/O/sub 7/)/sub 2/, CsGaHP/sub 3/O/sub 10/, Cs/sub 3/Ga/sub 3/P/sub 12/O/sub 36/. Their x-ray characteristics are given.

  16. A simple analytic solution for tachyon condensation

    Czech Academy of Sciences Publication Activity Database

    Erler, Theodore

    2010-01-01

    Roč. 163, č. 3 (2010), s. 705-709 ISSN 0040-5779 Grant - others:EUROHORC(XE) EYI/07/E010 Institutional research plan: CEZ:AV0Z10100502 Keywords : tachyon condensation * string field theory Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 0.748, year: 2010 http://www.springerlink.com/content/h22568xk246j1781/

  17. Landau damping in trapped Bose condensed gases

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, B; Zaremba, E [Department of Physics, Queen' s University, Kingston, ON K7L 3N6 (Canada)

    2003-07-01

    We study Landau damping in dilute Bose-Einstein condensed gases in both spherical and prolate ellipsoidal harmonic traps. We solve the Bogoliubov equations for the mode spectrum in both of these cases, and calculate the damping by summing over transitions between excited quasiparticle states. The results for the spherical case are compared to those obtained in the Hartree-Fock (HF) approximation, where the excitations take on a single-particle character, and excellent agreement between the two approaches is found. We have also taken the semiclassical limit of the HF approximation and obtain a novel expression for the Landau damping rate involving the time-dependent self-diffusion function of the thermal cloud. As a final approach, we study the decay of a condensate mode by making use of dynamical simulations in which both the condensate and thermal cloud are evolved explicitly as a function of time. A detailed comparison of all these methods over a wide range of sample sizes and trap geometries is presented.

  18. Measuring non-condensable gases in steam.

    Science.gov (United States)

    van Doornmalen, J P C M; Kopinga, K

    2013-11-01

    In surgery, medical devices that are used should be sterilized. To obtain surface steam sterilization conditions, not only in the sterilizer chamber itself but also in the loads to be sterilized, the amount of non-condensable gases (NCGs), for instance air, should be very low. Even rather small fractions of NCGs (below 1%) seriously hamper steam penetration in porous materials or devices with hollow channels (e.g., endoscopes). A recently developed instrument which might detect the presence of residual NCGs in a reliable and reproducible way is the 3M(TM) Electronic Test System (ETS). In this paper, a physical model is presented that describes the behavior of this instrument. This model has been validated by experiments in which known fractions of NCGs were introduced in a sterilizer chamber in which an ETS was placed. Despite several approximations made in the model, a good agreement is found between the model predictions and the experimental results. The basic principle of the ETS, measuring the heat transfer by condensation on a cooled surface, permits a very sensitive detection of NCGs in harsh environments like water vapor at high temperatures and pressures. Our model may serve to develop adapted and optimized versions of this instrument for use outside the field of sterilization, e.g., in heat exchangers based on steam condensation.

  19. Physics of hollow Bose-Einstein condensates

    Science.gov (United States)

    Padavić, Karmela; Sun, Kuei; Lannert, Courtney; Vishveshwara, Smitha

    2017-10-01

    Bose-Einstein condensate shells, while occurring in ultracold systems of coexisting phases and potentially within neutron stars, have yet to be realized in isolation on Earth due to the experimental challenge of overcoming gravitational sag. Motivated by the expected realization of hollow condensates by the space-based Cold Atomic Laboratory in microgravity conditions, we study a spherical condensate undergoing a topological change from a filled sphere to a hollow shell. We argue that the collective modes of the system show marked and robust signatures of this hollowing transition accompanied by the appearance of a new boundary. In particular, we demonstrate that the frequency spectrum of the breathing modes shows a pronounced depression as it evolves from the filled-sphere limit to the hollowing transition. Furthermore, when the center of the system becomes hollow surface modes show a global restructuring of their spectrum due to the availability of a new, inner, surface for supporting density distortions. We pinpoint universal features of this topological transition as well as analyse the spectral evolution of collective modes in the experimentally relevant case of a bubble-trap.

  20. Geysers advanced direct contact condenser research

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, J.; Bahning, T.; Bharathan, D.

    1997-12-31

    The first geothermal application of the Advanced Direct Contact Condenser (ADCC) technology developed by the National Renewable Energy Laboratory (NREL) is now operational and is being tested at The Geysers Power Plant Unit 11. This major research effort is being supported through the combined efforts of NREL, The Department of Energy (DOE), and Pacific Gas and Electric (PG&E). NREL and PG&E have entered into a Cooperative Research And Development Agreement (CRADA) for a project to improve the direct-contact condenser performance at The Geysers Power Plant. This project is the first geothermal adaptation of an advanced condenser design developed for the Ocean Thermal Energy Conversion (OTEC) systems. PG&E expects this technology to improve power plant performance and to help extend the life of the steam field by using steam more efficiently. In accordance with the CRADA, no money is transferred between the contracting parties. In this case the Department of Energy is funding NREL for their efforts in this project and PG&E is contributing funds in kind. Successful application of this technology at The Geysers will provide a basis for NREL to continue to develop this technology for other geothermal and fossil power plant systems.

  1. Improvements of condenser performance with granulate balls

    International Nuclear Information System (INIS)

    Bratthaell, L.

    1986-05-01

    At the nuclear power plant Oskarshamn has during time Nov 1983 - Apr 1985 test series been done to investigate the improvements of condensor performance with granulate balls. This type of ball is a normal sponge rubber ball coated with granulated plastic material. This material is, different from carborundum and pumice not abrasive to the tube material. The test results show that granulate balls give an improvement of the overall heat transfer coefficient of 5-7 percent compared to continous cleaning with normal sponge rubber balls. Granulate balls remove the utmost thin coating of organic material that the spong rubber balls are not able to remove and a practically metallic clean surface is established. This has been verified by laboratory inspection of tubes withdrawn from the tube bundle and site inspections of the condenser. When the condenser is cleaned by granulate balls during a period of about three days it is possible to keep the performance at a high level for a long time with continous cleaning with normal sponge rubber balls. After about three days the plastic layer on the balls is practically worned out. The balls have during that time fulfilled their function. The improvement in condenser temperature is 1,0-1,5 degree C. For the 02-turbine this means additional delivered energy of about 15000 MWh per year. (author)

  2. Análise de imagens em ensaios em modelo reduzido de estruturas de proteção costeira

    OpenAIRE

    Courela, Joana Maria Lopes

    2015-01-01

    Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra Os quebra-mares de talude são estruturas de proteção costeira que ao longo da sua vida útil, necessitam muitas vezes de manutenção e reparação. O dimensionamento hidráulico de um quebra-mar baseia-se habitualmente na utilização de fórmulas semi-empíricas, a partir das quais é obtido o peso dos blocos a utilizar. De forma a verificar a estabilidade da estrutura, ...

  3. Corrosão do aço inoxidável em estruturas de betão

    OpenAIRE

    Feliciano, Filipa João Lopes, 1989-

    2012-01-01

    Tese de mestrado em Química Tecnológica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012 O uso de aço inoxidável como armadura em estruturas de betão é visto como uma promissora medida preventiva de processos de corrosão, diminuindo o impacto socioeconómico das consequências de deterioração destas estruturas. No entanto, o elevado custo de implementação e o pouco conhecimento do comportamento do sistema, são obstáculos na aplicação prática e em larga escala des...

  4. Dois problemas em análise de formas de estruturas de ramificação

    OpenAIRE

    Jorge de Jesus Gomes Leandro

    2008-01-01

    O presente texto descreve métodos e apresenta resultados do projeto de pesquisa de mestrado intitulado \\"Dois Problemas em Análise de Formas de Estruturas de Ramificação\\". Ambos os problemas abordados estão relacionados às sub-áreas da Análise de Formas denominadas Caracterização e Descrição de Formas. O primeiro problema consiste na investigação de um conjunto de características propostas para distingüir, primeiramente, entre estruturas de ramificação de vasos sangüíneos em imagens de retin...

  5. Análise da estrutura organizacional e conceitual da educação especial brasileira (2008-2013

    Directory of Open Access Journals (Sweden)

    Franco Ezequiel Harlos

    2014-12-01

    Full Text Available Nesta pesquisa objetivou-se desvelar e analisar a estrutura organizacional e conceitual da Educação Especial brasileira, configurada nos documentos que orientam as políticas públicas relacionadas com esta modalidade de ensino e que foram publicados entre janeiro de 2008 e abril de 2013. Empregando-se pesquisa documental e análise categorial, efetuou-se a compilação e análise de trinta documentos apresentados no portal do Ministério de Educação como orientadores da Política Nacional de Educação Especial na Perspectiva da Educação Inclusiva. A análise da estrutura organizacional e conceitual da Educação Especial revelou a perpetuação de tradicionais contradições dos discursos associados com esta modalidade de ensino.

  6. Descrição de recursos em uma estrutura de metadados pautada no modelo FRBR

    Directory of Open Access Journals (Sweden)

    Elisabete Gonçalves de Souza

    2016-04-01

    Full Text Available Analisa os impactos da web semântica nos processos de organização e acesso à informação e as perspectivas trazidas pelo modelo conceitual FRBR para o cam-po da catalogação descritiva. Objetiva testar a aplicação de atributos FRAD em um repositório de modo a averiguar os limites e as possibilidades de uso de mo-delos conceituais na estrutura descritiva deste tipo de biblioteca digital. Demons-tra como o uso de modelos conceituais quando associado a outras tecnologias, como as boas práticas indicadas pelo uso de linked data, pode contribuir para enriquecer os processos de busca e recuperação da informação. Conclui que a possibilidade de substituir metadados textuais por identificadores universais permitirá que os agentes de softwares identifiquem com precisão as entidades essenciais à recuperação dos diferentes recursos, como as pessoas (criadoras das obras científicas, interligando o repositório, de forma lógica e segura, a outros dados disponíveis sobre elas na Web.

  7. Estrutura e processo assistencial de enfermagem ao paciente com câncer

    Directory of Open Access Journals (Sweden)

    Nilce Piva Adami

    1997-12-01

    Full Text Available Esta pesquisa objetivou avaliar a estrutura para o atendimento ao paciente com câncer e o processo asssistencial em quimioterapia antineoplásica. Foi realizada em seis unidades de internação e uma ambulatorial de um hospital universitário, utilizando-se a observação sistematizada e entrevista semi-estruturada, no período de janeiro a junho de 1996. Constatou-se que existem deficiências na área física e instalações das unidades estudadas. O pessoal de enfermagem, de modo geral, não possui preparo formal em Oncologia, com exceção do Setor de Quimioterapia. Verificou-se falta de sistematização da assistência de enfermagem e diferenças entre as unidades estudadas no que tange aos aspectos técnico-organizacionais da administração de antineoplásicos, bem como na interação entre profissionais e pacientes atendidos. As inadequações observadas poderiam ser minimizadas com uma política que contemple o aumento do financiamento do setor público da saúde, a implantação da sistematização da assistência e a inclusão da Oncologia na educação permanente do pessoal de enfermagem.

  8. Estrutura de uma floresta brejosa em substrato turfoso, Sul de Santa Catarina, Brasil

    Directory of Open Access Journals (Sweden)

    Rafael Martins

    2013-04-01

    Full Text Available Objetivou-se descrever a diversidade e a estrutura do componente lenhoso de uma floresta brejosa em substrato turfoso no sul do Estado de Santa Catarina, correlacionando dados florísticos com variáveis ambientais. Indivíduos com DAP ≥ 5 cm foram amostrados em 100 parcelas de 10 x 10 m em um quadrado permanente de 1 ha. As variáveis ambientais foram classificadas em topográficas, químicas e texturais do solo e de luminosidade. Correlações espécie-ambiente foram obtidas por Análise de Correspondência Canônica (CCA. Comparações florísticas foram realizadas por análise de agrupamento (UPGMA e análise de correspondência. A diversidade específica foi considerada baixa, pois foram amostradas apenas 26 espécies. A CCA evidenciou que as variáveis ambientais mensuradas possuem pouca influência na distribuição das espécies, ressaltando assim sua adaptação ao ambiente anóxico, fortemente limitante. Dados de similaridade demonstraram que o substrato turfoso age como um filtro ambiental adicional, além do estresse hídrico, na composição de espécies nas formações turfosas/brejosas.

  9. Estrutura de uma Floresta Tropical com Caesalpinia echinata Lam. (Pau Brasil

    Directory of Open Access Journals (Sweden)

    Valderes Bento Sarnaglia Junior

    2014-04-01

    Full Text Available Este trabalho teve por objetivo analisar a estrutura da vegetação do componente arbóreo em um remanescente de Floresta Ombrófila Densa das Terras Baixas com populações naturais de Caesalpinia echinata Lam. (pau-brasil no município de Aracruz (ES. Foram instaladas 10 parcelas de 10 x 50 m, de modo sistemático, totalizando 0,5 ha de área amostral. Todos os indivíduos com DAP (Diâmetro à Altura do Peito  ≥10 cm foram amostrados. Amostraram-se 259 indivíduos distribuídos em 119 espécies. As famílias com maior riqueza de espécies foram Leguminosae (22, Sapotaceae (9 e Myrtaceae (9. As espécies com os mais altos valores de importância foram Eriotheca macrophylla (K. Schum. A. Robyns, Caesalpinia echinata Lam. e Astrocaryum aculeatissimum (Schott Burret. O índice de Shannon (H’ foi de 4,51 e a equabilidade (J’ foi de 0,94.  O fragmento apresenta sinais de perturbações antrópicas, porém os altos valores de diversidade e riqueza mostram a importância da conservação, assim como para a preservação de C. echinata.

  10. Estrutura metabólica e genética de comunidades bacterianas em solo de cerrado sob diferentes manejos

    Directory of Open Access Journals (Sweden)

    Leandro Moraes de Souza

    2012-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a estrutura metabólica e genética de comunidades bacterianas em Latossolo de cerrado sob vegetação nativa ou cultivado em sistema de rotação soja/milho sob preparo convencional e plantio direto. Foram utilizadas microplacas EcoPlate para determinar o perfil e a diversidade metabólica das comunidades bacterianas, e eletroforese em gel com gradiente desnaturante (DGGE para avaliar a estrutura genética. O teste estatístico de Mantel foi utilizado para avaliar a relação entre a estrutura metabólica e a genética. A comunidade bacteriana sob vegetação nativa apresentou perfil metabólico diferente do encontrado em solos cultivados. No solo cultivado com soja sob preparo convencional, o padrão de utilização das fontes de carbono diferenciou-se dos demais tratamentos. Com base nos resultados de DGGE, a comunidade bacteriana sob vegetação nativa apresentou 35% de similaridade com as de áreas cultivadas. Foram formados grupos distintos de comunidades bacterianas do solo entre as áreas sob preparo convencional e plantio direto. Houve correlação significativa de 62% entre as matrizes geradas pelas microplacas EcoPlate e pela DGGE. Variações no perfil metabólico estão relacionadas às variações na estrutura genética das comunidades bacterianas do solo.

  11. On inflation in the presence of a gaugino condensate

    International Nuclear Information System (INIS)

    Lebedev, Oleg; Papineau, Chloe

    2009-07-01

    We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)

  12. On inflation in the presence of a gaugino condensate

    International Nuclear Information System (INIS)

    Lebedev, Oleg; Papineau, Chloe; Postma, Marieke

    2010-01-01

    We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.

  13. On inflation in the presence of a gaugino condensate

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Oleg; Papineau, Chloe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Postma, Marieke [NIKHEF, Amsterdam (Netherlands)

    2009-07-15

    We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)

  14. On inflation in the presence of a gaugino condensate

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Oleg [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Papineau, Chloe, E-mail: chloe.papineau@desy.d [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Postma, Marieke [NIKHEF, Kruislaan 409, 1098 Amsterdam (Netherlands)

    2010-02-08

    We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.

  15. Competition between Bose-Einstein Condensation and Spin Dynamics.

    Science.gov (United States)

    Naylor, B; Brewczyk, M; Gajda, M; Gorceix, O; Maréchal, E; Vernac, L; Laburthe-Tolra, B

    2016-10-28

    We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations.

  16. A INFLUÃNCIA DA ESTRUTURA ORGANIZACIONAL NA EXECUÃÃO DOS PROCESSOS DE MANUTENÃÃO

    Directory of Open Access Journals (Sweden)

    Gustavo A. C. Guzman

    2003-12-01

    Full Text Available No contexto atual de competitividade, uma eficiência maior dos processos executados pelo departamento de manutenção é um dos fatores que contribui paRI o aumento de produtividade das empresas. Diferentes autores têm reconhecido a importância da estrutura organizacional do departamento de manutençào no seu desempenho. Entretanto, esses autores não detalham a influência da estrutura organizacional para a adequada execução dos processos de manutenção. Este artigo descreve um trabalho cujo objetivo foi procurar entender como a estrutura organizacional influência os processos do departamento de manutenção de urna empresa. Para isso foram realizados uma vasta pesquisa bibliográfica relativa ao gerenciamento de manutenção e à teoria sobre análise organizacional, além de um estudo de caso numa empresa de grande porte. O trabalho apresentado neste artigo serve como piloto e base para estudos futuros. As conclusões, se confirmadas em pesquisas posteriores, poderão subsidiar acomplementação da teoria existente.

  17. Mineralogia da fração argila e estrutura de latossolos da região sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    M. M. Ferreira

    1999-09-01

    Full Text Available Este trabalho objetivou estudar a relação entre os constituintes mineralógicos da fração argila e o desenvolvimento da micro e macroestrutura de Latossolos do sudeste brasileiro. Para tanto, foram obtidas amostras do horizonte B de sete Latossolos, representativos deste grupamento, ocorrentes nos estados de Minas Gerais e Espírito Santo. As diferentes amostras foram submetidas à caracterização morfológica, química, física, mineralógica e micromorfológica. A partir dos diferentes resultados, foi possível concluir que caulinita e gibbsita são os principais constituintes mineralógicos responsáveis pelo desenvolvimento da estrutura dos Latossolos estudados. Latossolos cauliníticos apresentam estrutura em blocos, reflexo do ajuste face a face das placas de caulinita, enquanto os gibbsíticos apresentam estrutura granular, reflexo da ausência daquele ajuste.

  18. Influência da estrutura molecular dos policarboxilatos na hidratação do cimento Portland

    Directory of Open Access Journals (Sweden)

    Carolina Martínez Rojas

    Full Text Available O objetivo deste trabalho é apresentar os dados de literatura que enfatizam a influência da estrutura molecular de policarboxilatos na hidratação do cimento, estudada por ensaios de calor de hidratação, tempos de pega e análise termogravimétrica em pastas de cimento. Com essa mesma metodologia foram avaliados dois policarboxilatos, agente ativo de dois aditivos nacionais cujas estruturas moleculares diferem no tamanho das cadeias laterais. Tanto os dados da literatura quanto os resultados dos ensaios realizados mostram que o fator da estrutura molecular do policarboxilato que determina o retardo da pasta de cimento é a densidade de carga aniônica presente no sistema, a qual é maior quanto menor a densidade de cadeias laterais. Adicionalmente, se comparada a influência na hidratação do cimento de policarboxilatos com igual densidade de cadeias laterais, porém, de tamanhos diferentes, utilizados em igual quantidade em massa, observa-se que aqueles com cadeias laterais menores geram maior retardo.

  19. Governança em estruturas proprietárias concentradas: novas evidências para o Brasil

    Directory of Open Access Journals (Sweden)

    Igor Bernardi Sonza

    2014-06-01

    Full Text Available Neste artigo, o objetivo é analisar a influência da estrutura de propriedade na eficiência das empresas de capital aberto brasileiras, em que é identificada maior concentração de ações nas mãos de um grupo restrito de pessoas. No estudo, unem-se técnicas de otimização estática por meio de análise envoltória de dados, para identificar a eficiência das empresas de capital aberto, com dados em painel, para identificar a influência da estrutura de propriedade na eficiência das empresas, buscando agregar governança corporativa à literatura de eficiência produtiva no contexto de diferenças institucionais no ambiente brasileiro, a fim de complementar os estudos prévios que consideram somente os outputs como medidas de eficiência. Nos resultados obtidos, mostra-se que a estrutura de propriedade influencia negativamente a eficiência, contrariando grande parte dos estudos baseados no modelo norte-americano e evidenciando que as peculiaridades dos países devem ser levadas em consideração, principalmente com relação à sua origem legal.

  20. 40 CFR 405.110 - Applicability; description of the condensed whey subcategory.

    Science.gov (United States)

    2010-07-01

    ... condensed whey subcategory. 405.110 Section 405.110 Protection of Environment ENVIRONMENTAL PROTECTION... Condensed Whey Subcategory § 405.110 Applicability; description of the condensed whey subcategory. The... whey and condensed acid whey. ...

  1. Quantification of chromatin condensation level by image processing.

    Science.gov (United States)

    Irianto, Jerome; Lee, David A; Knight, Martin M

    2014-03-01

    The level of chromatin condensation is related to the silencing/activation of chromosomal territories and therefore impacts on gene expression. Chromatin condensation changes during cell cycle, progression and differentiation, and is influenced by various physicochemical and epigenetic factors. This study describes a validated experimental technique to quantify chromatin condensation. A novel image processing procedure is developed using Sobel edge detection to quantify the level of chromatin condensation from nuclei images taken by confocal microscopy. The algorithm was developed in MATLAB and used to quantify different levels of chromatin condensation in chondrocyte nuclei achieved through alteration in osmotic pressure. The resulting chromatin condensation parameter (CCP) is in good agreement with independent multi-observer qualitative visual assessment. This image processing technique thereby provides a validated unbiased parameter for rapid and highly reproducible quantification of the level of chromatin condensation. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  2. Estrutura e estratégia: evolução de paradigmas Structure and strategy: evolution of paradigms

    Directory of Open Access Journals (Sweden)

    Fernando Carvalho de Almeida

    2006-06-01

    Full Text Available O presente trabalho analisa as relações de interdependência existentes entre a estrutura da empresa e as estratégias a serem implementadas. É feita uma breve revisão da literatura sobre estratégia, administração estratégica e as diversas formas de conduzir a implementação das que se apresentam como as mais adequadas à consecução dos objetivos organizacionais. Foram analisados os modelos tradicionais de estrutura organizacional, bem como as vantagens e desvantagens estratégicas que cada um apresenta. Por fim, foram estudadas as abordagens de diferentes autores sobre as relações de interdependência entre a estrutura da empresa e as suas estratégias. Em conclusão, verifica-se que, embora as estratégias da empresa possam ser fixadas a partir da análise da sua estrutura organizacional, dos seus pontos fortes e fracos, esta atitude nem sempre é viável. Numa época em que as tecnologias evoluem de forma extremamente rápida e a competitividade se acelera em nível global, tornam-se necessárias estruturas organizacionais flexíveis, que possam modificar-se rapidamente, para atender às estratégias capazes de permitir a adequada inserção da empresa em um ambiente externo extremamente volátil.The interdependent relations that exist between the structure of an organization and the organizational strategies to be implemented were analyzed. A review was made of literature on strategy, strategic management and methods of implementing strategies appropriate for organization objectives. Traditional models of organization structures were then analyzed as well as the inherent strategic advantages and disadvantages. Then the approach of various authors to these interdependent relations was studied. It was concluded that although organizational strategy can be established by analyzing organization structure as well as the strong and weak aspects involved, this is not always feasible. With fast paced technologies and sharpening global

  3. Assessment of RELAP5/MOD3.3 condensation models for the tube bundle condensation in the PCCS of ESBWR

    International Nuclear Information System (INIS)

    Zhou, W.; Wolf, B.; Revankar, S.T.

    2011-01-01

    The passive containment condenser system (PCCS) in an ESBWR reactor consists of vertical tube bundle submerged in a large pool of water. The condensation model for the PCCS in a thermalhydraulics code RELAP5/MOD3.3 consists of the default Nusselt model and an alternate condensation model from UCB condensation correlation. An assessment of the PCCS condensation model in RELAP5/MOD3.3 was carried out using experiments conducted on a single tube and tube bundle PCCS tests at Purdue University. The experimental conditions were simulated with the default and the alternate condensation models in the REALP5/MOD3.3 beta version of the code. The default model and the UCB model (alternate model) give quite different results on condensation heat transfer for the PCCS. The default model predicts complete condensation well whereas the UCB model predicts the through flow condensation well. Based on this study it was found that none of the models in REALP5 can predict complete condensation as well as the through flow condensation well. (author)

  4. Condensation energy density in Bi-2212 superconductors

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Kiuchi, Masaru; Haraguchi, Teruhisa; Imada, Takeki; Okamura, Kazunori; Okayasu, Satoru; Uchida, Satoshi; Shimoyama, Jun-ichi; Kishio, Kohji

    2006-01-01

    The relationship between the condensation energy density and the anisotropy parameter, γ a , has been derived for Bi-2212 superconductors in various anisotropic states by analysing the critical current density due to columnar defects introduced by heavy ion irradiation. The critical current density depended on the size of the defects, determined by the kind and irradiation energy of the ions. A significantly large critical current density of 17.0 MA cm -2 was obtained at 5 K and 0.1 T even for the defect density of a matching field of 1 T in a specimen irradiated with iodine ions. The dependence of the critical current density on the size of the defects agreed well with the prediction from the summation theory of pinning forces, and the condensation energy density could be obtained consistently from specimens irradiated with different ions. The condensation energy density obtained increased with decreasing γ a over the entire range of measurement temperature, and reached about 60% of the value for the most three-dimensional Y-123 observed by Civale et al at 5 K. This gives the reason for the very strong pinning in Bi-2212 superconductors at low temperatures. The thermodynamic critical field obtained decreased linearly with increasing temperature and extrapolated to zero at a certain characteristic temperature, T * , lower than the critical temperature, T c . T * , which seems to be associated with the superconductivity in the block layers, was highest for the optimally doped specimen. This shows that the superconductivity becomes more inhomogeneous as the doped state of a superconductor deviates from the optimum condition

  5. Estrutura, ultraestrutura e morfometria da veia cava de paca (Cuniculus paca Linnaeus, 1766 criada em cativeiro

    Directory of Open Access Journals (Sweden)

    Sérgio Pinter Garcia Filho

    2013-05-01

    Full Text Available A paca (Cuniculus paca é o segundo maior roedor da fauna brasileira. Apresenta carne de excelente qualidade, o que incentiva a criação comercial. Além disso, este animal pode tornar-se uma opção válida em experimentação embora poucas sejam as informações detalhadas sobre sua morfologia. Assim, objetivou-se descrever a morfologia, morfometria e ultraestrutura de segmentos das porções cranial e caudal da veia cava de quatro pacas (Cuniculus paca adultas excedentes do plantel do Setor de Animais Silvestres do Departamento de Zootecnia da FCAV-Unesp. Os segmentos venosos foram analisados à microscopia de luz e à microscopia eletrônica de varredura. Foram mensuradas as espessuras do complexo formado pelas túnicas íntima e média, além da túnica adventícia e analisou-se os resultados pela estatística descritiva, teste "T" pareado (p<0,05. Em relação à espessura das túnicas estudadas, comprovou-se que os valores da espessura das túnicas íntima, média e adventícia, para todos os animais, foram significativamente maiores no segmento cranial. As camadas das paredes dos vasos apresentaram variações entre si quanto à estrutura e espessura, supostamente devido a uma adaptação à exigência funcional.

  6. Comportamento espectral de materiais de solos e de estruturas biogênicas associadas

    Directory of Open Access Journals (Sweden)

    J. A. M. Demattê

    1998-12-01

    Full Text Available No presente estudo, verificou-se a interferência da macrofauna edáfica sobre os atributos físicos e químicos e sua relação com a reflectância espectral de um Latossolo Vermelho-Amarelo (LV, Terra Roxa Estruturada latossólica (TR e Vertissolo (V. Esses solos localizam-se em três pontos ao longo de uma toposseqüência da região de Piracicaba (SP. As amostras foram direcionadas para os agregados formados pelas formigas cortadeiras (Atta sp., cupins (Cornitermes cumulans e minhocas (Pontoscolex corethrurus, os quais foram comparados com o solo-controle sem atividade visível e recente dos animais (testemunha. Foram avaliadas a granulometria e a composição química das amostras de solo. O comportamento espectral do solo foi obtido em laboratório, utilizando espectroradiômetro entre 400 e 2.500 nm. Os coprólitos de minhoca apresentaram 2 a 3 vezes mais fósforo e um incremento de 30 a 50% na matéria orgânica em relação ao horizonte superficial do solo. Os agregados de cupins e formigas apresentaram composição química semelhante à dos horizontes subsuperficiais dos solos. O comportamento espectral dos agregados biológicos variou conforme sua composição química e profundidade de ação dos animais. No caso da minhoca, as curvas de reflectância foram semelhantes às do horizonte superficial para os três solos. Para as estruturas de cupim e formiga, tanto a composição química como o comportamento espectral corresponderam ao horizonte subsuperficial no LV e TR.

  7. Estrutura e significado em "Uma rosa para Emily", de William Faulkner

    Directory of Open Access Journals (Sweden)

    Carlos Daghlian

    2004-01-01

    Full Text Available Trata-se de uma análise do consagrado conto "Uma Rosa para Emily", de William Faulkner, voltada para alguns dos principais aspectos de sua estrutura. Após considerarmos o enredo, discutimos a construção das personagens, com destaque para a protagonista, fazendo um levantamento e comentários sobre possíveis fontes de inspiração, destacando, entre outras, aspectos da biografia da poeta Emily Dickinson, a ficção e a poesia de E. A. Poe, romances de Charles Dickens e Henry James, o conto de Sherwood Anderson e a poesia de William Blake, Emily Dickinson, Robert Browning e John Crowe Ransom, acrescentando paralelos com o conto "Bartleby, o escrivão", de Herman Melville. Analisamos, então, o foco narrativo, os símbolos e o significado, ressaltando aqui o desenvolvimento temático da narrativa.This is an analysis of the well-known short story "A Rose for Emily," by William Faulkner, concentrating on some of the main aspects of its structure. A consideration of the plot is followed by a discussion of characterization, with emphasis on the protagonist, by means of a survey and comments on possible sources of inspiration including, among others, aspects of Emily Dickinson's biography, E. A. Poe's fiction and poetry, novels by Charles Dickens and Henry James, Sherwood Anderson's short stories, and the poetry of William Blake, Emily Dickinson, Robert Browning, and John Crowe Ransom, in addition to Herman Melville's short story "Bartleby, the Scrivener." The narrative focus, symbolism and meaning, stressing the thematic development of the narrative, are then analyzed.

  8. Composição e estrutura de uma floresta ribeirinha no sul do Brasil

    Directory of Open Access Journals (Sweden)

    Daniel Dutra Saraiva

    2011-09-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2011v24n4p49 A vegetação ribeirinha ocupa uma das áreas mais dinâmicas da paisagem, e apresenta espécies altamente especializadas e adaptadas a uma variedade de distúrbios ocorrentes na zona ripária. Foi realizado um levantamento fitossociológico com o objetivo de descrever a composição florística e a estrutura fitossociológica do componente arbóreo, assim como destacar algumas características dinâmicas das espécies que o compõem, em uma floresta ribeirinha no rio Jaguarão, sul do Brasil.  Foram amostradas todas as árvores com DAP ≥ 5 cm em 25 parcelas de 10 × 10 m (0,25 ha. Foram registradas 725 árvores vivas pertencentes a 27 espécies, 24 gêneros e 16 famílias botânicas, e 51 mortas ainda em pé. As famílias com maior riqueza específica foram Myrtaceae e Salicaceae. As espécies com os maiores valores de cobertura (VC e de importância (VI foram Sebastiania commersoniana, Allophylus edulis, Eugenia uniflora e Pouteria salicifolia, acumulando mais de 80% da abundância total registrada.  A diversidade (H’ foi estimada em 1,84 nats.ind.-1 e a equabilidade (J’ em 0,56 nats.ind.-1. Prevaleceram espécies zoocóricas de categorias inciais e intermediárias de sucessão, sendo em sua maior parte provenientes do contingente oeste de migração e de ampla distribuição nas regiões sudeste e sul do Brasil.

  9. Aspectos da estrutura da raiz e do desenvolvimento de plantas de soja em solos compactados

    Directory of Open Access Journals (Sweden)

    QUEIROZ-VOLTAN RACHEL BENETTI

    2000-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da compactação do solo na anatomia da raiz e no desenvolvimento de duas cultivares de soja (Glycine max (L. Merrill, IAC-8 e IAC-14, em vasos. O solo utilizado foi um Latossolo Roxo, tirado da camada superficial (0-200 mm. Os níveis de compactação consistiram de 0,95 (controle, 1,20, 1,35 e 1,50 kg L-1, e foram obtidos pela compactação de determinada massa de solo por prensa hidráulica, em cilindros de ferro. A compactação do solo não afetou a estrutura anatômica da raiz, em nenhuma das duas cultivares. Na cultivar IAC-8, o número de folhas, a altura das plantas e o peso da matéria seca da raiz e do caule diminuíram com o aumento da densidade do solo, e o comprimento da raiz aumentou. Na cultivar IAC-14, o número de folhas, a área foliar, o número de vagens, a altura das plantas, o peso da matéria seca da raiz, do caule e das folhas foram diminuindo à medida que aumentava a densidade do solo, embora nas densidades intermediárias (1,20 e 1,35 se tenha notado uma tendência de aumento naquelas variáveis. A produção de soja não foi afetada pela compactação do solo, com exceção do número de vagens da cultivar IAC-14, que apresentou diferenças em razão do tratamento. Os resultados sugerem que as duas cultivares podem ser bem adaptadas a solos compactados, nos níveis analisados.

  10. Vortex molecules in Bose-Einstein condensates

    OpenAIRE

    Nitta, Muneto; Eto, Minoru; Cipriani, Mattia

    2013-01-01

    Stable vortex dimers are known to exist in coherently coupled two component Bose-Einstein condensates (BECs). We construct stable vortex trimers in three component BECs and find that the shape can be controlled by changing the internal coherent (Rabi) couplings. Stable vortex N-omers are also constructed in coherently coupled N-component BECs. We classify all possible N-omers in terms of the mathematical graph theory. Next, we study effects of the Rabi coupling in vortex lattices in two-compo...

  11. Dissipative phenomena in condensed matter some applications

    CERN Document Server

    Dattagupta, Sushanta

    2004-01-01

    From the field of nonequilibrium statistical physics, this graduate- and research-level volume treats the modeling and characterization of dissipative phenomena. A variety of examples from diverse disciplines like condensed matter physics, materials science, metallurgy, chemical physics etc. are discussed. Dattagupta employs the broad framework of stochastic processes and master equation techniques to obtain models for a wide range of experimentally relevant phenomena such as classical and quantum Brownian motion, spin dynamics, kinetics of phase ordering, relaxation in glasses, dissipative tunneling. It provides a pedagogical exposition of current research material and will be useful to experimentalists, computational physicists and theorists.

  12. Bose-Einstein Condensation in Complex Networks

    Energy Technology Data Exchange (ETDEWEB)

    Bianconi, Ginestra; Barabasi, Albert-Laszlo

    2001-06-11

    The evolution of many complex systems, including the World Wide Web, business, and citation networks, is encoded in the dynamic web describing the interactions between the system's constituents. Despite their irreversible and nonequilibrium nature these networks follow Bose statistics and can undergo Bose-Einstein condensation. Addressing the dynamical properties of these nonequilibrium systems within the framework of equilibrium quantum gases predicts that the {open_quotes}first-mover-advantage,{close_quotes} {open_quotes}fit-get-rich,{close_quotes} and {open_quotes}winner-takes-all{close_quotes} phenomena observed in competitive systems are thermodynamically distinct phases of the underlying evolving networks.

  13. Construction of the blowdown and condensation loop

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choon Kyung; Song, Chul Kyung; Cho, Seok; Chun, S. Y.; Chung, Moon Ki

    1997-12-01

    The blowdown and condensation loop (B and C loop) has been constructed to get experimental data for designing the safety depressurization system (SDS) and steam sparger which are considered to implement in the Korea Next Generation Reactor (KNGR). In this report, system description on the B and C loop is given in detail, which includes the drawings and technical specification of each component, instrumentation and control system, and the operational procedures and the results of the performance testing. (author). 7 refs., 11 tabs., 48 figs.

  14. Long range correlations in condensed matter

    International Nuclear Information System (INIS)

    Bochicchio, R.C.

    1990-01-01

    Off diagonal long range order (ODLRO) correlations are strongly related with the generalized Bose-Einstein condensation. Under certain boundary conditions, one implies the other. These phenomena are of great importance in the description of quantum situations with a macroscopic manifestation (superfluidity, superconductivity, etc.). Since ion pairs are not bosons, the definition of ODLRO is modified. The information contained with the 2-particle propagator (electron pairs) and the consequences that lead to pairs statistics are shown in this presentation. The analogy between long range correlations and fluids is also analyzed. (Author). 17 refs

  15. Diffusion in condensed matter methods, materials, models

    CERN Document Server

    Kärger, Jörg

    2005-01-01

    Diffusion as the process of particle transport due to stochastic movement is a phenomenon of crucial relevance for a large variety of processes and materials. This comprehensive, handbook- style survey of diffusion in condensed matter gives detailed insight into diffusion as the process of particle transport due to stochastic movement. Leading experts in the field describe in 23 chapters the different aspects of diffusion, covering microscopic and macroscopic experimental techniques and exemplary results for various classes of solids, liquids and interfaces as well as several theoretical concepts and models. Students and scientists in physics, chemistry, materials science, and biology will benefit from this detailed compilation.

  16. HADRONIC SCATTERING IN THE COLOR GLASS CONDENSATE.

    Energy Technology Data Exchange (ETDEWEB)

    VENUGOPALAN, R.

    2005-05-15

    Multi-particle production in QCD is dominated by higher twist contributions. The operator product expansion is not very effective here because the number of relevant operators grow rapidly with increasing twist. The Color Glass Condensate (CGC) provides a framework in QCD to systematically discuss ''classical'' (multiple scattering) and ''quantum'' evolution (shadowing) effects in multi-particle production. The apparently insuperable problem of nucleus-nucleus scattering in QCD simplifies greatly in the CGC. A few examples are discussed with emphasis on open problems.

  17. Exhaled Breath Condensate for Proteomic Biomarker Discovery

    Directory of Open Access Journals (Sweden)

    Sean W. Harshman

    2014-07-01

    Full Text Available Exhaled breath condensate (EBC has been established as a potential source of respiratory biomarkers. Compared to the numerous small molecules identified, the protein content of EBC has remained relatively unstudied due to the methodological and technical difficulties surrounding EBC analysis. In this review, we discuss the proteins identified in EBC, by mass spectrometry, focusing on the significance of those proteins identified. We will also review the limitations surrounding mass spectral EBC protein analysis emphasizing recommendations to enhance EBC protein identifications by mass spectrometry. Finally, we will provide insight into the future directions of the EBC proteomics field.

  18. A color magnetic vortex condensate in QCD

    International Nuclear Information System (INIS)

    Ambjoern, J.; Olesen, P.

    1980-03-01

    It is shown that there exists a very close analogy between a lattice of vorticies in a superconductor near the critical field and a condensate of color magnetic flux tubes due to the unstable mode in QCD. This analogy makes it possible to identify a dynamical Higgs field in QCD. It is shown that the color magnetic flux tubes are quantized in terms of the center group Z(2) in the SU(2) case. In the case of SU(N) it is possible to select a color direction of the field such that one has Z(N) quantization. (Auth.)

  19. STRANGE BARYONIC MATTER AND KAON CONDENSATION

    Czech Academy of Sciences Publication Activity Database

    Gazda, Daniel; Friedman, E.; Gal, A.; Mareš, Jiří

    2011-01-01

    Roč. 26, 3-4 (2011), s. 567-569 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/09/1441 Institutional research plan: CEZ:AV0Z10480505 Keywords : (K)over-bar-nuclear bound states * strange baryonic matter * kaon condensation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

  20. Potentially Prebiotic Syntheses of Condensed Phosphates

    Science.gov (United States)

    Keefe, Anthony D.; Miller, Stanley L.

    1996-01-01

    In view of the importance of a prebiotic source of high energy phosphates, we have investigated a number of potentially prebiotic processes to produce condensed phosphates from orthophosphate and cyclic trimetaphosphate from tripolyphosphate. The reagents investigated include polymerizing nitriles, acid anhydrides, lactones, hexamethylene tetramine and carbon suboxide. A number of these processes give substantial yields of pyrophosphate from orthophosphate and trimetaphosphate from tripolyphosphate. Although these reactions may have been applicable in local areas, they are not sufficiently robust to have been of importance in the prebiotic open ocean.

  1. The dielectric function of condensed systems

    CERN Document Server

    Keldysh, LV; Kirzhnitz, DA

    1989-01-01

    Much progress has been made in the understanding of the general properties of the dielectric function and in the calculation of this quantity for many classes of media. This volume gathers together the considerable information available and presents a detailed overview of the present status of the theory of electromagnetic response functions, whilst simultaneously covering a wide range of problems in its application to condensed matter physics.The following subjects are covered:- the dielectric function of the homogeneous electron gas, of crystalline systems, and of inh

  2. Bose-Einstein Condensation in Complex Networks

    International Nuclear Information System (INIS)

    Bianconi, Ginestra; Barabasi, Albert-Laszlo

    2001-01-01

    The evolution of many complex systems, including the World Wide Web, business, and citation networks, is encoded in the dynamic web describing the interactions between the system's constituents. Despite their irreversible and nonequilibrium nature these networks follow Bose statistics and can undergo Bose-Einstein condensation. Addressing the dynamical properties of these nonequilibrium systems within the framework of equilibrium quantum gases predicts that the 'first-mover-advantage,' 'fit-get-rich,' and 'winner-takes-all' phenomena observed in competitive systems are thermodynamically distinct phases of the underlying evolving networks

  3. Hidden Scale Invariance in Condensed Matter

    DEFF Research Database (Denmark)

    Dyre, J. C.

    2014-01-01

    . This means that the phase diagram becomes effectively one-dimensional with regard to several physical properties. Liquids and solids with isomorphs include most or all van der Waals bonded systems and metals, as well as weakly ionic or dipolar systems. On the other hand, systems with directional bonding...... (hydrogen bonds or covalent bonds) or strong Coulomb forces generally do not exhibit hidden scale invariance. The article reviews the theory behind this picture of condensed matter and the evidence for it coming from computer simulations and experiments...

  4. Disoriented chiral condensate: Theory and phenomenology

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1997-12-01

    These notes are an abbreviated version of lectures given at the 1997 Zakopane School. They contain two topics. The first is a description in elementary terms of the basic ideas underlying the speculative hypothesis that pieces of strong-interaction vacuum with a rotated chiral order parameter, disoriented chiral condensate or DCC, might be produced in high energy elementary particle collisions. The second topic is a discussion of the phenomenological techniques which may be applied to data in order to experimentally search for the existence of DCC

  5. Liquid-Infused Smooth Surface for Improved Condensation Heat Transfer.

    Science.gov (United States)

    Tsuchiya, Hirotaka; Tenjimbayashi, Mizuki; Moriya, Takeo; Yoshikawa, Ryohei; Sasaki, Kaichi; Togasawa, Ryo; Yamazaki, Taku; Manabe, Kengo; Shiratori, Seimei

    2017-09-12

    Control of vapor condensation properties is a promising approach to manage a crucial part of energy infrastructure conditions. Heat transfer by vapor condensation on superhydrophobic coatings has garnered attention, because dropwise condensation on superhydrophobic surfaces with rough structures leads to favorable heat-transfer performance. However, pinned condensed water droplets within the rough structure and a high thermodynamic energy barrier for nucleation of superhydrophobic surfaces limit their heat-transfer increase. Recently, slippery liquid-infused surfaces (SLIPS) have been investigated, because of their high water sliding ability and surface smoothness originating from the liquid layer. However, even on SLIPS, condensed water droplets are eventually pinned to degrade their heat-transfer properties after extended use, because the rough base layer is exposed as infused liquid is lost. Herein, we report a liquid-infused smooth surface named "SPLASH" (surface with π electron interaction liquid adsorption, smoothness, and hydrophobicity) to overcome the problems derived from the rough structures in previous approaches to obtain stable, high heat-transfer performance. The SPLASH displayed a maximum condensation heat-transfer coefficient that was 175% higher than that of an uncoated substrate. The SPLASH also showed higher heat-transfer performance and more stable dropwise condensation than superhydrophobic surfaces and SLIPS from the viewpoints of condensed water droplet mobility and the thermodynamic energy barrier for nucleation. The effects of liquid-infused surface roughness and liquid viscosity on condensation heat transfer were investigated to compare heat-transfer performance. This research will aid industrial applications using vapor condensation.

  6. Development of balanced downflow type surface condensers, (2)

    International Nuclear Information System (INIS)

    Tomida, Akira; Oshima, Yoshikuni; Okochi, Isao; Izumi, Kenkichi.

    1976-01-01

    As the size of the condensers for power generation plants grew large, the new balanced downflow type condenser was developed and completed on the basis of the experiment on steam flow according to the two-dimensional flow model, the analysis of the performance in a tube nest with a computer, and the studies on the effect of outside liquid film and the reheating deaeration of condensate. When the balanced downflow type condensers were adopted for actual plants, the construction, strength and production method were examined, and the reliability of the new condenser was confirmed by the thermal characteristic experiment with the model similar to the actual machine. The condenser comprises a condenser body, supporting plates, cooling tubes, tube plates, water chambers, and reinforcements, and the cooling tubes are arranged so as to exchange heat effectively. The arrangement of tubes is divided into three regions, namely radiation portion, densely arranged portion, and air cooling portion. In the balanced downflow type condensers, the dilution by utilizing condensate is provided against ammonia attack. The apparatuses for the thermal characteristic experiment and the experimental results, and the results of the performance test on the actual balanced downflow type condenser are reported. (Kako, I.)

  7. GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS AMONG ASSAYS AND CONDENSATES

    Science.gov (United States)

    The particulate fraction of cigarette smoke, cigarette smoke condensate (CSC), is genotoxic in many short-term in vitro tests and carcinogenic in rodents. However, no study has evaluatedd a set of CSCs prepared from a diverse set of cigarettes in a variety of short-term genotoxic...

  8. Regioselective Synthesis of Procyanidin B6, A 4-6-Condensed (+-Catechin Dimer, by Intramolecular Condensation

    Directory of Open Access Journals (Sweden)

    Yusuke Higashino

    2018-01-01

    Full Text Available Proanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+-catechin-(4-6-(+-catechin dimer, by Lewis acid-catalyzed intramolecular condensation. The 5-O-t-butyldimethylsilyl (TBDMS group of 5,7,3′4′-tetra-O-TBDMS-(+-catechin was regioselectively removed using trifluoroacetic acid, leading to the “regio-controlled” synthesis of procyanidin B6. The 5-hydroxyl group of the 7,3′,4′-tri-O-TBDMS-(+-catechin nucleophile and the 3-hydroxyl group of 5,7,3′,4′-tetra-O-benzylated-(+-catechin electrophile were connected with an azelaic acid. The subsequent SnCl4-catalyzed intramolecular condensation proceeded smoothly to give the 4-6-condensed catechin dimer. This is the first report on the complete regioselective synthesis of a 4-6-connected oligomer without modifying the 8-position.

  9. Condensation phenomena in a turbine blade passage

    International Nuclear Information System (INIS)

    Skillings, S.A.

    1989-02-01

    The mechanisms associated with the formation and growth of water droplets in the large low-pressure (LP) turbines used for electrical power generation are poorly understood and recent measurements have indicated that an unusually high loss is associated with the initial nucleation of these droplets. In order to gain an insight into the phenomena which arise in the turbine situation, some experiments were performed to investigate the behaviour of condensing steam flows in a blade passage. This study has revealed the fundamental significance of droplet nucleation in modifying the single-phase flow structure and results are presented which show the change in shock wave pattern when inlet superheat and outlet Mach number are varied. The trailing-edge shock wave structure appears considerably more robust towards variation of inlet superheat than purely one-dimensional considerations may suggest and the inadequacies of adopting a one-dimensional theory to analyse multi-dimensional condensing flows are demonstrated. Over a certain range of outlet Mach numbers an oscillating shock wave will establish in the throat region of the blade passage and this has been shown to interact strongly with droplet nucleation, resulting in a considerably increased mean droplet size. The possible implications of these results for turbine performance are also discussed. (author)

  10. Inverted Leidenfrost-like Effect during Condensation.

    Science.gov (United States)

    Narhe, Ramchandra; Anand, Sushant; Rykaczewski, Konrad; Medici, Marie-Gabrielle; González-Viñas, Wenceslao; Varanasi, Kripa K; Beysens, Daniel

    2015-05-19

    Water droplets condensing on solidified phase change materials such as benzene and cyclohexane near their melting point show in-plane jumping and continuous "crawling" motion. The jumping drop motion has been tentatively explained as an outcome of melting and refreezing of the materials surface beneath the droplets and can be thus considered as an inverted Leidenfrost-like effect (in the classical case vapor is generated from a droplet on a hot substrate). We present here a detailed investigation of jumping movements using high-speed imaging and static cross-sectional cryogenic focused ion beam scanning electron microscope imaging. Our results show that drop motion is induced by a thermocapillary (Marangoni) effect. The in-plane jumping motion can be delineated to occur in two stages. The first stage occurs on a millisecond time scale and comprises melting the substrate due to drop condensation. This results in droplet depinning, partial spreading, and thermocapillary movement until freezing of the cyclohexane film. The second stage occurs on a second time scale and comprises relaxation motion of the drop contact line (change in drop contact radius and contact angle) after substrate freezing. When the cyclohexane film cannot freeze, the droplet continuously glides on the surface, resulting in the crawling motion.

  11. NUCLEAR CONDENSATE AND HELIUM WHITE DWARFS

    International Nuclear Information System (INIS)

    Bedaque, Paulo F.; Berkowitz, Evan; Cherman, Aleksey

    2012-01-01

    We consider a high-density region of the helium phase diagram, where the nuclei form a Bose-Einstein condensate rather than a classical plasma or a crystal. Helium in this phase may be present in helium-core white dwarfs. We show that in this regime there is a new gapless quasiparticle not previously noticed, arising when the constraints imposed by gauge symmetry are taken into account. The contribution of this quasiparticle to the specific heat of a white dwarf core turns out to be comparable in a range of temperatures to the contribution from the particle-hole excitations of the degenerate electrons. The specific heat in the condensed phase is two orders of magnitude smaller than in the uncondensed plasma phase, which is the ground state at higher temperatures, and four orders of magnitude smaller than the specific heat that an ion lattice would provide, if formed. Since the specific heat of the core is an important input for setting the rate of cooling of a white dwarf star, it may turn out that such a change in the thermal properties of the cores of helium white dwarfs has observable implications.

  12. Open problems in condensed matter physics, 1987

    International Nuclear Information System (INIS)

    Falicov, L.M.

    1988-08-01

    The 1970's and 1980's can be considered the third stage in the explosive development of condensed matter physics. After the very intensive research of the 1930's and 1940's, which followed the formulation of quantum mechanics, and the path-breaking activity of the 1950's and 1960's, the problems being faced now are much more complex and not always susceptible to simple modelling. The (subjectively) open problems discussed here are: high temperature superconductivity, its properties and the possible new mechanisms which lead to it; the integral and fractional quantum Hall effects; new forms of order in condensed-matter systems; the physics of disorder, especially the problem of spin glasses; the physics of complex anisotropic systems; the theoretical prediction of stable and metastable states of matter; the physics of highly correlated states (heavy fermions); the physics of artificially made structures, in particular heterostructures and highly metastable states of matter; the determination of the microscopic structure of surfaces; and chaos and highly nonlinear phnomena. 82 refs

  13. Equation of state of warm condensed matter

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, T.W., III; Young, D.A.; Rogers, F.J.

    1998-03-01

    Recent advances in computational condensed matter theory have yielded accurate calculations of properties of materials. These calculations have, for the most part, focused on the low temperature (T=0) limit. An accurate determination of the equation of state (EOS) at finite temperature also requires knowledge of the behavior of the electron and ion thermal pressure as a function of T. Current approaches often interpolate between calculated T=0 results and approximations valid in the high T limit. Plasma physics-based approaches are accurate in the high temperature limit, but lose accuracy below T{approximately}T{sub Fermi}. We seek to ``connect up`` these two regimes by using ab initio finite temperature methods (including linear-response[1] based phonon calculations) to derive an equation of state of condensed matter for T{<=}T{sub Fermi}. We will present theoretical results for the principal Hugoniot of shocked materials, including carbon and aluminum, up to pressures P>100 GPa and temperatures T>10{sup 4}K, and compare our results with available experimental data.

  14. The Solar Photosphere: Evidence for Condensed Matter

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2006-04-01

    Full Text Available The stellar equations of state treat the Sun much like an ideal gas, wherein the photosphere is viewed as a sparse gaseous plasma. The temperatures inferred in the solar interior give some credence to these models, especially since it is counterintuitive that an object with internal temperatures in excess of 1 MK could be existing in the liquid state. Nonetheless, extreme temperatures, by themselves, are insufficient evidence for the states of matter. The presence of magnetic fields and gravity also impact the expected phase. In the end, it is the physical expression of a state that is required in establishing the proper phase of an object. The photosphere does not lend itself easily to treatment as a gaseous plasma. The physical evidence can be more simply reconciled with a solar body and a photosphere in the condensed state. A discussion of each physical feature follows: (1 the thermal spectrum, (2 limb darkening, (3 solar collapse, (4 the solar density, (5 seismic activity, (6 mass displacement, (7 the chromosphere and critical opalescence, (8 shape, (9 surface activity, (10 photospheric/coronal flows, (11 photospheric imaging, (12 the solar dynamo, and (13 the presence of Sun spots. The explanation of these findings by the gaseous models often requires an improbable combination of events, such as found in the stellar opacity problem. In sharp contrast, each can be explained with simplicity by the condensed state. This work is an invitation to reconsider the phase of the Sun.

  15. The development of air cooled condensation systems

    International Nuclear Information System (INIS)

    Bodas, J.

    1990-01-01

    EGI - Contracting/Engineering has had experience with the development of air cooled condensing systems since the 1950's. There are two accepted types of dry cooling systems,the direct and the indirect ones. Due to the fact that the indirect system has several advantages over the direct one, EGI's purpose was to develop an economic, reliable and efficient type of indirect cooling system, both for industrial and power station applications. Apart from system development, the main components of dry cooling plant have been developed as well. These are: the water-to-air heat exchangers; the direct contact (DC, or jet) condenser; the cooling water circulating pumps and recovery turbines; and the peak cooling/preheating units. As a result of this broad development work which was connected with intensive market activity, EGI has supplied about 50% of the dry cooling plants employed for large power stations all over the world. This means that today the cumulated capacity of power units using Heller type dry cooling systems supplied and contracted by EGI is over 6000 MW

  16. Condensed matter view of giant resonance phenomena

    International Nuclear Information System (INIS)

    Zangwill, A.

    1987-01-01

    The intent of this article is to present a view of giant resonance phenomena (an essentially atomic phenomenon) from the perspective of a condensed matter physicist with an interest in the optical properties of matter. As we shall see, this amounts to a particular prejudice about how one should think about many-body effects in a system of interacting electrons. Some of these effects are special to condensed matter systems and will be dealt with in the second half of this paper. However, it turns out that the authors view of the main ingredient to a giant resonance differs significantly from that normally taken by scientists trained in the traditional methods of atomic physics. Therefore, in the first section the author will take advantage of the fact that his contribution to this volume was composed and delivered to the publishers somewhat after the conclusion of the School (rather than before as requested by the organizers) and try to clearly distinguish the differences of opinion presented by the lecturers from the unalterable experimental facts. 46 references, 9 figures

  17. Aspects of Landau condensation in atomic physics

    International Nuclear Information System (INIS)

    Gay, J.C.

    1980-01-01

    Some aspects of Landau condensation in atomic physics are reviewed both as regards current work on Rydberg states under laboratory conditions and from the viewpoint of the prospects of spontaneous decay of neutral vacuum with superheavy elements. The characteristics of the hydrogen-atom spectrum in a strong magnetic field are presented and discussed using essentially semiclassical arguments. Some schematic attempt at a global interpretation of the Rydberg spectrum near the ionization limit is also given. Then the action of an electric field on the quasi-Landau spectrum is discussed. The conditions for spontaneous production of positrons from neutral vacuum decay with superheavy elements are reconsidered for the case when the system experiences ultrastrong magnetic fields, as in pulsars and white dwarfs. It is shown that spontaneous decay of neutral vacuum may occur at lower Z values than 169. The possible importance of such effects during heavy-ion collisions is briefly discussed. We deal with some qualitative trends of the problem of an atom in a magnetic field with particular emphasis on diamagnetic effects. In the last few years, we have had the capability of making accurate experimental investigations of Rydberg atoms, and perhaps in the future we will develop fundamentally new means of studying heavy-ion collisions. Accordingly it seems of interest to make qualitative remarks regarding the present state of the problem and the possible importance of Landau condensation in various domains of atomic physics now under active development. (author)

  18. Quark and gluon condensate in vacuum

    International Nuclear Information System (INIS)

    Vajnshtejn, A.I.; Zakharov, V.I.; Shifman, M.A.

    1979-01-01

    The mechanism of quark confinement has been reviewed. The fact that coloured particles in a free state cannot be observed is connected with specific properties of vacuum in quantum chromodynamics. The basic hypothesis consists in the existence of vacuum fields, quark and gluon condensates, which affect the coloured objects. The vacuum transparent relative to noncharged ''white'' states serves as a source of the force acting upon the coloured particles. It has been a sucess to examine strictly the action of the vacuum fields on quarks when the distance between them is relatively small and the force of the vacuum fields on quarks is relatively small too. It is shown that the interaction with the vacuum fields manifests itself earlier than the forces connected with the gluon exchange do. It is assumed that the vacuum condensate of quarks and gluons and its relation to properties of resonances and to the bag model exist in reality. The dispersion sum rules are used for calculating masses and lepton widths of resonances

  19. DFT Investigation of the Diastereoselectivity of the MX2and MX3Lewis-Acid-Catalyzed Mukaiyama Aldol Reaction between C,O,O-Tris(trimethylsilyl)ketene Acetal and Aldehydes.

    Science.gov (United States)

    Mohamed, Slim Hadj; Champagne, Benoît; Trabelsi, Mahmoud

    2018-03-01

    The kinetics and diastereoselectivity of the Mukaiyama aldol reaction between C,O,O-tris(trimethylsilyl)ketene acetal and aldehydes bearing alkyl, vinyl, and aromatic substituents is influenced by the nature of Lewis acid catalysts. A density functional theory investigation using the M06-2X exchange-correlation functional and the PCM scheme to account for solvent effects has been carried out to characterize the structure and energetics of the transition state when the Lewis acid is ZnBr 2 (MX 2 ) or GaCl 3 (MX 3 ) in comparison to the uncatalyzed reaction. The main observations are that (i) the pro-syn transition states are always more stable than the pro-anti ones; (ii) for MX 2 , the transition state presents a cyclic structure, whereas it is open for MX 3 , owing to steric interactions; (iii) the difference of activation free enthalpy between the pro-anti and pro-syn transition states decreases when the reaction is catalyzed, by either MX 2 or MX 3 , demonstrating a reduction of the diastereoselectivity with respect to the uncatalyzed reaction; (iv) this decrease of diastereoselectivity is larger for MX 3 - than for MX 2 -catalyzed reactions; and (v) the MX 3 -catalyzed reactions are kinetically favored by 1-2 kcal mol -1 with respect to the MX 2 ones.

  20. Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

    KAUST Repository

    Gemici, Zekeriyya

    2009-03-11

    Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

  1. Entropy generation in a condenser and related correlations

    Directory of Open Access Journals (Sweden)

    Askowski Rafał

    2015-06-01

    Full Text Available The paper presents an analysis of relations describing entropy generation in a condenser of a steam unit. Connections between entropy generation, condenser ratio, and heat exchanger effectiveness, as well as relations implied by them are shown. Theoretical considerations allowed to determine limits of individual parameters which describe the condenser operation. Various relations for average temperature of the cold fluid were compared. All the proposed relations were verified against data obtained using a simulator and actual measurement data from a 200 MW unit condenser. Based on data from a simulator it was examined how the sum of entropy rates, steam condenser effectiveness, terminal temperature difference and condenser ratio vary with the change in the inlet cooling water temperature, mass flow rate of steam and the cooling water mass flow rate.

  2. Assessment of Condenser Design in the Cooling System of PWR

    International Nuclear Information System (INIS)

    Sukmanto Dibyo

    2008-01-01

    This paper explains various cases related to the problem of condenser design principle. Condenser equipment is circuit component of cooling that is very important. Steam that goes down from the turbine, flowing to the condenser and the steam is condensate to be water. Step of design is beginning from identification of problem until mechanic design. Usually, the condenser is designed by conservative certain levels, as well as thermal aspect or mechanic. Beside that, the design analysis is also anticipated to the existing of degradation due to aging therefore safety aspect and requirement are accepted. The assessment that related to the condenser design has been discussed. Most important aspect is obtaining of performances. Beside that, the discussion is also described about design method and that complication should consider aspect of thermal design, physics, economic, aspect of corrosion and others factors. (author)

  3. Suppressing Ice Nucleation of Supercooled Condensate with Biphilic Topography

    Science.gov (United States)

    Hou, Youmin; Yu, Miao; Shang, Yuhe; Zhou, Peng; Song, Ruyuan; Xu, Xiaonan; Chen, Xuemei; Wang, Zuankai; Yao, Shuhuai

    2018-02-01

    Preventing or minimizing ice formation in supercooled water is of prominent importance in many infrastructures, transportation, and cooling systems. The overall phase change heat transfer on icephobic surfaces, in general, is intentionally sacrificed to suppress the nucleation of water and ice. However, in a condensation frosting process, inhibiting freezing without compromising the water condensation has been an unsolved challenge. Here we show that this conflict between anti-icing and efficient condensation cooling can be resolved by utilizing biphilic topography with patterned high-contrast wettability. By creating a varying interfacial thermal barrier underneath the supercooled condensate, the biphilic structures tune the nucleation rates of water and ice in the sequential condensation-to-freezing process. Our experimental and theoretical investigation of condensate freezing dynamics further unravels the correlation between the onset of droplet freezing and its characteristic radius, offering a new insight for controlling the multiphase transitions among vapor, water, and ice in supercooled conditions.

  4. Comparison of condensation correlations in CATHARE for modelling isolation condenser experiment

    International Nuclear Information System (INIS)

    Sorjonen, J.; Kalli, H.

    1996-01-01

    CATHARE is a thermal-hydraulic computer code developed at the Centre d'Etudes Nucleaires de Grenoble (CENG) for nuclear power plant safety analysis. Behaviour of a new Cathare condensation correlation have been studied. The code has been applied to Isolation Condenser (IC) experiment conducted in PIPER-ONE facility. PIPER-ONE simulates a General Electric BWR-6 with volume and height scaling ratios 1/2200 and 1/1, respectively. The facility is installed at Dipartimento di Costruzioni Meccaniche e Nucleari of Pisa University. The facility was equipped with an once-through heat exchanger immersed in a pool of ambient temperature water, installed roughly 10 m above the core, in the aim to reproduce qualitatively the phenomenologies expected for Isolation Condenser in the Simplified BWR (SBWR). Experiment PO-IC-02 included two subsequent power levels with initial pressure of 5.1 MPa. The IC was active during the whole experiment except in the time period between the two different power levels. A previous calculation of above mentioned experiment by Cathare2 V1.3E showed some lacks in the condensation correlation of the code. A new correlation has been developed in Centre d'Etudes Nucleaires de Grenoble (CENG). The new calculation of the PO-IC-02 experiment by Cathare2 Vl.3U 1 with the new correlation gave results consistent with the experiment in the condensing zone of the IC. Also the overall pressure trend was reproduced with estimated heat losses to the environment. A comparison with previously obtained Relap5/Mod3. 1 results is also shown in the present document. (author) (18 refs.)

  5. Sobre a revisão da norma brasileira de projeto de estruturas de aço e estruturas mistas de aço e concreto, a NBR 8800

    OpenAIRE

    Fakury,Ricardo Hallal

    2007-01-01

    Esse artigo apresenta, inicialmente, um breve histórico dos trabalhos de revisão da norma brasileira de projeto de estruturas de aço e mistas de aço e concreto, que culminaram no projeto de norma de setembro de 2006, denominado aqui de PR NBR 8800:2006. Em seguida, procura fornecer as bases utilizadas na produção do PR NBR 8800:2006, as diretrizes fundamentais seguidas e as principais mudanças ocorridas em relação à norma em vigência, datada de 1986. Finalmente, procura destacar a importância...

  6. A simple air-cooled reflux condenser for laboratory use

    International Nuclear Information System (INIS)

    Boult, K.A.

    1979-10-01

    This Memorandum describes the design of a simple compact air-cooled reflux condenser suitable for gloveboxes, cells or other locations where the provision of cooling water presents a problem. In a typical application the condenser functioned satisfactorily when used to condense water from a flask heated by a 100 watt mantle. There was no measurable loss of water from the boiling flask in 100 hours. (author)

  7. Generation of dark solitons in oscillating Bose-Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Theocharis, G. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-4515 (United States); Nistazakis, H.E. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece); Department of Telecommunications Science and Technology, University of Peloponnese, Tripolis 22100 (Greece); Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece)]. E-mail: dfrantz@cc.uoa.gr; Bishop, A.R. [Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2005-04-11

    We propose an experimentally tractable setting for observing an 'instability' of a repulsive oscillating Bose-Einstein condensate that leads to the generation of dark solitons. We illustrate that when the trap of the condensate (which incorporates a localized impurity) is displaced so that the condensate flow is characterized by an atomic velocity larger than the local speed of sound, dark solitons are generated. The subcritical, near critical and supercritical are analyzed in detail.

  8. Synchronous Condenser Allocation for Improving System Short Circuit Ratio

    DEFF Research Database (Denmark)

    Jia, Jundi; Yang, Guangya; Nielsen, Arne Hejde

    2018-01-01

    With converter-based renewable energy sources increasingly integrated into power systems and conventional power plants gradually phased out, future power systems will experience reduced short circuit strength. The deployment of synchronous condensers can serve as a potential solution. This paper...... presents an optimal synchronous condenser allocation method for improving system short circuit ratio at converter point of common coupling using a modified short circuit analysis approach. The total cost of installing new synchronous condensers is minimized while the system short circuit ratios...

  9. Incorporation of Condensation Heat Transfer in a Flow Network Code

    Science.gov (United States)

    Anthony, Miranda; Majumdar, Alok

    2002-01-01

    Pure water is distilled from waste water in the International Space Station. The distillation assembly consists of an evaporator, a compressor and a condenser. Vapor is periodically purged from the condenser to avoid vapor accumulation. Purged vapor is condensed in a tube by coolant water prior to entering the purge pump. The paper presents a condensation model of purged vapor in a tube. This model is based on the Finite Volume Method. In the Finite Volume Method, the flow domain is discretized into multiple control volumes and a simultaneous analysis is performed.

  10. Theory of decoherence in Bose-Einstein condensate interferometry

    International Nuclear Information System (INIS)

    Dalton, B J

    2007-01-01

    A full treatment of decoherence and dephasing effects in BEC interferometry has been developed based on using quantum correlation functions for treating interferometric effects. The BEC is described via a phase space distribution functional of the Wigner type for the condensate modes and the positive P type for the non-condensate modes. Ito equations for stochastic condensate and non-condensate field functions replace the functional Fokker-Planck equation for the distribution functional and stochastic averages of field function products determine the quantum correlation functions

  11. Cytoskeletal Reorganization Drives Mesenchymal Condensation and Regulates Downstream Molecular Signaling.

    Directory of Open Access Journals (Sweden)

    Poulomi Ray

    Full Text Available Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF, Bone Morphogenetic Protein (BMP and Transforming Growth Factor beta (TGF-β signaling pathways. Rho Kinase (ROCK-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis.

  12. 1D models for condensation induced water hammer in pipelines

    International Nuclear Information System (INIS)

    Bloemeling, Frank; Neuhas, Thorsten; Schaffrath, Andreas

    2013-01-01

    Condensation induced water hammer (CIWH) are caused by contact of steam and subcooled water. Thus, modeling the direct contact condensation is a crucial step towards the simulation of condensation induced water hammer with 1D pressure surge codes. Therefore, also the TUeV NORD SysTec GmbH and Co. KG inhouse pressure surge code DYVRO has been equipped with a new contact condensation model. The validation of DYVRO against an experiment dealing with CIWH is presented in this contribution. (orig.)

  13. Cytoskeletal Reorganization Drives Mesenchymal Condensation and Regulates Downstream Molecular Signaling

    Science.gov (United States)

    Ray, Poulomi; Chapman, Susan C.

    2015-01-01

    Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF), Bone Morphogenetic Protein (BMP) and Transforming Growth Factor beta (TGF-β) signaling pathways. Rho Kinase (ROCK)-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis. PMID:26237312

  14. Evaporation and condensation at a liquid surface. II. Methanol

    Science.gov (United States)

    Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

    1994-11-01

    The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

  15. Atenção primária em diabetes no Sul do Brasil: estrutura, processo e resultado

    Directory of Open Access Journals (Sweden)

    Assunção Maria Cecília F

    2001-01-01

    Full Text Available OBJETIVO: Descrever e avaliar a estrutura, o processo e o resultado do cuidado do paciente diabético atendido em nível primário de atenção à saúde em Pelotas, RS. MÉTODOS: O delineamento foi transversal. Foram estudados todos os 32 postos de saúde e 61 médicos que atendem pacientes diabéticos nesses locais. Foi identificada uma amostra de 378 pacientes que tiveram consulta médica nos postos. Os pacientes foram entrevistados em casa, e sua glicemia capilar, pressão arterial e índice de massa corporal foram avaliados e comparados a padrões. Componentes da estrutura e do processo de atendimento foram comparados a padrões recomendados ao manejo de pacientes diabéticos. RESULTADOS: A maioria dos serviços carece de aproximadamente todos os requerimentos mínimos. A aferição da pressão arterial foi o item do exame físico mais relatado na visita inicial. Como plano de tratamento na consulta inicial, cerca de 85% dos médicos relataram prescrever dieta, e 72% exercício físico. Todos os médicos relataram solicitar glicemia de jejum, e 60% hemoglobina glicosilada na monitorização laboratorial dos pacientes. O controle da doença variou de 6% a 11%, conforme os diferentes parâmetros utilizados. CONCLUSÕES: A rede pública de saúde está deficiente, mas existe potencial de melhoria dos três aspectos (estrutura, processo e resultado através de treinamento em serviço e seguimento de normas-padrão.

  16. Atenção primária em diabetes no Sul do Brasil: estrutura, processo e resultado

    Directory of Open Access Journals (Sweden)

    Maria Cecília F Assunção

    2001-02-01

    Full Text Available OBJETIVO: Descrever e avaliar a estrutura, o processo e o resultado do cuidado do paciente diabético atendido em nível primário de atenção à saúde em Pelotas, RS. MÉTODOS: O delineamento foi transversal. Foram estudados todos os 32 postos de saúde e 61 médicos que atendem pacientes diabéticos nesses locais. Foi identificada uma amostra de 378 pacientes que tiveram consulta médica nos postos. Os pacientes foram entrevistados em casa, e sua glicemia capilar, pressão arterial e índice de massa corporal foram avaliados e comparados a padrões. Componentes da estrutura e do processo de atendimento foram comparados a padrões recomendados ao manejo de pacientes diabéticos. RESULTADOS: A maioria dos serviços carece de aproximadamente todos os requerimentos mínimos. A aferição da pressão arterial foi o item do exame físico mais relatado na visita inicial. Como plano de tratamento na consulta inicial, cerca de 85% dos médicos relataram prescrever dieta, e 72% exercício físico. Todos os médicos relataram solicitar glicemia de jejum, e 60% hemoglobina glicosilada na monitorização laboratorial dos pacientes. O controle da doença variou de 6% a 11%, conforme os diferentes parâmetros utilizados. CONCLUSÕES: A rede pública de saúde está deficiente, mas existe potencial de melhoria dos três aspectos (estrutura, processo e resultado através de treinamento em serviço e seguimento de normas-padrão.

  17. Sobre um hiper-romance ou a estrutura narrativa de Se um viajante numa noite de inverno, de Italo Calvino

    Directory of Open Access Journals (Sweden)

    Tatiane Aparecida da Silva Severino

    2015-04-01

    Full Text Available O romance Se um viajante numa noite de inverno (1979 encerra a produção ficcional de Italo Calvino da década de 1970, composta ainda por As cidades invisíveis (1972 e O castelo dos destinos cruzados (1973. Esses livros são resultantes de um intenso trabalho de pesquisa, com o qual Calvino busca e testa novas formas e materiais para composição literária, impactando notadamente a organização narrativa. A pesquisa objetivou estudar a estrutura narrativa de Se um viajante numa noite de inverno, buscando compreender como se dá a interação entre os diferentes níveis narrativos da obra. Para tanto foram realizadas análises descritivas desta e os dados obtidos foram estudados à luz do conceito de mise en abyme, reportados por Rita (2014, e das reflexões acerca dos pronomes pessoais no romance, expostas por Butor (1977 e Cacciatori (1990. Verificou-se que a estrutura narrativa divide-se em dois níveis distintos: romance-moldura e microrromances, que, por sua vez, se entrelaçam. Além disso, notou-se o emprego do recurso da mise en abyme, tanto no nível enunciativo quanto do enunciado, instaurando a relação especular. Concluiu-se que esses elementos são responsáveis pela articulação dos dois planos narrativos e pela organicidade da estrutura modular do romance.

  18. Estruturação de redes sociais virtuais em organizações: um estudo de caso

    Directory of Open Access Journals (Sweden)

    Debora Bobsin

    2014-06-01

    Full Text Available O uso das redes sociais virtuais resulta em mudanças nas interações e na comunicação entre pessoas e grupos. Como as pesquisas têm enfatizado menos a adoção e o uso dessas redes nas organizações, o objetivo neste estudo é compreender o processo de estruturação das redes sociais virtuais em organizações, usando a teoria da estruturação como base. Analisou-se esse processo em uma organização universitária em consolidação, adotando o estudo de caso como metodologia e a observação participante como principal técnica de coleta de dados. Identificou-se que as redes representaram um importante vetor de formação de identidade e de construção de significados para os participantes e para a própria organização. Com base nos objetivos e propósitos dos participantes das redes, em suas interações criaram-se e recriaram-se estruturas e alteraram-se papéis, regras e o uso de recursos (tecnológicos e outros. Como conclusão, destacam-se os principais elementos de uma rede social virtual e seus usos por organizações, e são oferecidos direcionamentos para pesquisas futuras.

  19. Economia de redes, externalidades e estruturas de mercado: o conceito de concorrência qualitativa

    Directory of Open Access Journals (Sweden)

    Alain Herscovici

    2013-05-01

    Full Text Available This paper aims to realize, from Rohfls’ model, a micro and meso analyze of the electronic networks and of internet. In regard to the complexity of the Information and Communication System (ICS, I will add the variables that correspond to these evolutions, and I will study the new competition forms. In this regard, I will propose a typology of the different markets, and I will demonstrate why the markets where the competition is qualitative are the most competitive. In a first part, I will present Rohfls’ model, I will show how the complexification of the system explains the emergence of new forms of competition, and I will highlight the limits of this model, in regard to these evolutions. In a second part, I will add some variables to Rohfls’ model, and I will construct a typology of the different kinds of competition and of market structures.O objetivo deste trabalho consiste em realizar, a partir do modelo de Rohfls,  uma análise micro e mesoeconômica das redes eletrônicas e da internet. Em função da complexificação dos Sistemas de Informação e Comunicação (SIC , acrescentarei as  variáveis que correspondem a essas evoluções, e analisarei as novas formas concorrenciais que caracterizam esses mercados. A este respeito, proporei uma tipologia dos diferentes mercados, e mostrarei porque os mercados nos quais se exerce uma concorrência qualitativa são os mais concorrenciais. Em uma primeira parte, apresentarei o modelo de Rohlfs (1974,  mostrarei em que medida   a complexificação do SIC se traduz por novas modalidades de concorrência, e ressaltarei os limites explicativos deste modelo diante dessas evoluções. Numa segunda parte,  acrescentarei uma série de variáveis ao modelo original de Rohlfs, e  construirei assim uma tipologia das diferentes formas de concorrência e das estruturas de mercado.

  20. Análise de impactos socioambientais da infra-estrutura de transporte na Bacia do Purus-AM.

    OpenAIRE

    Andrés Leandro Gumiero Jaime

    2008-01-01

    A bacia do rio Purus, na Amazônia Ocidental, apesar de figurar como uma das menos antropizadas bacias da margem direita do complexo Solimões-Amazonas, já apresenta pontos de impacto antrópico associado à expansão da fronteira agropecuária. Tal impacto tem no estabelecimento da infra-estrutura de transportes seu principal eixo de avanço. Foi feita a simulação de alguns trechos de rodovias interligando municípios correspondente ao médio Purus (conforme designação proposta por SOUSA JÚNIOR et al...

  1. As estruturas de sentimento história e desenvolvimento da noção cultural por Raymond Williams

    OpenAIRE

    Oliveira, Luciano Dutra de

    2017-01-01

    A presente dissertação tem como escopo principal discutir a noção de “Estruturas de Sentimento” desenvolvida por Raymond Williams (1921-1988) no período compreendido entre 1950 e 1977. Seu objetivo, portanto, é localizar tal formulação teórica no conjunto da produção do autor acerca de temas interligados como cultura, política, literatura e comunicação, identificando, em alguma medida, sua gênese histórica (especialmente em seus quatro primeiros livros) seu desenvolvimento nas obras posterior...

  2. Desempenho de ligantes geopoliméricos na reparação de estruturas de betão

    OpenAIRE

    Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, Said

    2007-01-01

    Apresentam-se, neste artigo, alguns resultados sobre o desenvolvimento de um novo material ligante geopolimérico, obtido por activação alcalina de lamas residuais das Minas da Panasqueira (AALRM) e a possibilidade da sua utilização como material de reparação de estruturas de betões de cimento portland normal (CPN). Foi investigada a aderência entre betões CPN e três materiais de reparação ; um ligante geopolimérico AALRM e dois produtos comerciais. A aderência foi avaliada através da quantif...

  3. A estrutura da oração em línguas indígenas brasileiras

    Directory of Open Access Journals (Sweden)

    MAIA Marcus

    1999-01-01

    Full Text Available Compara-se neste artigo um conjunto de fatos relacionados a interface sintaxe/morfologia em quatro línguas indígenas brasileiras, a saber, Kuikuro, Guarani, Karaja e Tikuna. Investiga-se o papel das categorias funcionais na derivação da estrutura básica da oração nessas línguas. Discutem-se os problemas que se colocam para a linearização da ordem SOV, propondo-se análises alternativas.

  4. Estruturas mistas em madeira-concreto: uma técnica racional para pontes de estradas vicinais

    OpenAIRE

    Soriano,Julio; Mascia,Nilson Tadeu

    2009-01-01

    De modo geral, a aplicação racional de materiais de construção requer o desenvolvimento ou aprimoramento de técnicas construtivas. Nesse sentido, a utilização do concreto e da madeira, materiais tradicionais e de grande aceitação em construções rurais, formando estruturas mistas, constitui-se em uma solução viável por apresentar desempenhos estrutural e econômico adequados, bem como boa durabilidade. Particularmente, a efetivação desse sistema estrutural deve ser assegurada por meio de uma li...

  5. Composição floristica e estrutura da comunidade arborea num gradiente altitudinal da Mata Atlantica

    OpenAIRE

    Maryland Sanchez Lacerda

    2001-01-01

    Resumo: Este estudo foi realizado para verificar como ocorrem as mudanças na composição e estrutura da vegetação com a altitude, em uma montanha com 1200 m.s.m. localizada no Parque Estadual da Serra do Mar - Núcleo Picinguaba, município de Ubatuba, SP. A vegetação é considerada como Floresta Ombrófila Densa, genericamente chamada Mata Atlântica. A área de estudo escolhida foi uma encosta situada no vale formado pelos Morros do Corisco e Cuscuzeiro, cobrindo a bacia hidrográfica formada pelos...

  6. Efeitos do pastoreio de bovinos na estrutura populacional de plantas em fragmentos de floresta ombrófila mista

    OpenAIRE

    Sampaio,Maurício Bonesso; Guarino,Ernestino de Souza Gomes

    2007-01-01

    Fragmentos de Floresta Ombrófila Mista têm sido freqüentemente utilizados para o manejo de bovinos na região do médio rio Pelotas, Sul do Brasil. Para avaliar o efeito dos animais na estrutura populacional de Araucaria angustifolia, Clethra scabra, Dicksonia sellowiana e Maytenus ilicifolia, foram amostrados sítios, sujeitos à alta e baixa intensidade de pastoreio, em cinco fragmentos, utilizando-se parcelas de 20 x 20 m. Apesar do pequeno tamanho dos fragmentos e da alta perturbação pelo man...

  7. Cadeia reversa do óleo de cozinha: coordenação, estrutura e aspectos relacionais

    OpenAIRE

    Zucatto,Luis Carlos; Welle,Iara; Silva,Tania Nunes da

    2013-01-01

    As atividades de produção e consumo geram resíduos que, conforme o destino, produzem impactos negativos no meio ambiente. Essa situação agravou-se, de maneira crítica, a partir da Revolução Industrial. Para reaproveitar esses resíduos, são necessárias novas formas de produzir, consumir e dar um destino adequado aos produtos após o final de seu ciclo de vida útil. Com base nesse contexto, o objetivo deste estudo é analisar como se estrutura e é coordenada uma cadeia de suprimentos reversa, ten...

  8. Adequabilidade da estrutura produtiva das empresas de celulose de mercado, no Brasil, para competir em preço.

    OpenAIRE

    Hildebrando Hilton de Souza Oliveira

    2009-01-01

    Este trabalho replica pesquisa, no campo da estratégia competitiva, especificamente investigando a adequabilidade da estrutura produtiva das empresas de celulose de mercado, sediadas no Brasil, para produzir com custos baixos buscando competitividade em preço. O trabalho apresenta uma breve análise do setor de celulose e papel, no Brasil, e faz também uma revisão da literatura sobre estratégia, centrando-se sobre aspectos da teoria da competitividade de Contador (1996). Palavras-cha...

  9. A duality web in condensed matter systems

    Science.gov (United States)

    Ma, Chen-Te

    2018-03-01

    We study various dualities in condensed matter systems. The dualities in three dimensions can be derived from a conjecture of a duality between a Dirac fermion theory and an interacting scalar field theory at a Wilson-Fisher fixed point and zero temperature in three dimensions. We show that the dualities are not affected by non-trivial holonomy, use a mean-field method to study the dualities, and discuss the dualities at a finite temperature. Finally, we combine a bulk theory, which is an Abelian p-form theory with a theta term in 2 p + 2 dimensions, and a boundary theory, which is a 2 p + 1 dimensional theory, to discuss constraints and difficulties of a 2 p + 1 dimensional duality web.

  10. Vortex Molecules in Bose-Einstein Condensates

    Science.gov (United States)

    Nitta, Muneto; Eto, Minoru; Cipriani, Mattia

    2014-04-01

    Stable vortex dimers are known to exist in coherently coupled two component Bose-Einstein condensates (BECs). We construct stable vortex trimers in three component BECs and find that the shape can be controlled by changing the internal coherent (Rabi) couplings. Stable vortex N-omers are also constructed in coherently coupled N-component BECs. We classify all possible N-omers in terms of the mathematical graph theory. Next, we study effects of the Rabi coupling in vortex lattices in two-component BECs. We find how the vortex lattices without the Rabi coupling known before are connected to the Abrikosov lattice of integer vortices with increasing the Rabi coupling. In this process, vortex dimers change their partners in various ways at large couplings. We then find that the Abrikosov lattices are robust in three-component BECs.

  11. Black holes as quantum gravity condensates

    Science.gov (United States)

    Oriti, Daniele; Pranzetti, Daniele; Sindoni, Lorenzo

    2018-03-01

    We model spherically symmetric black holes within the group field theory formalism for quantum gravity via generalized condensate states, involving sums over arbitrarily refined graphs (dual to three-dimensional triangulations). The construction relies heavily on both the combinatorial tools of random tensor models and the quantum geometric data of loop quantum gravity, both part of the group field theory formalism. Armed with the detailed microscopic structure, we compute the entropy associated with the black hole horizon, which turns out to be equivalently the Boltzmann entropy of its microscopic degrees of freedom and the entanglement entropy between the inside and outside regions. We recover the area law under very general conditions, as well as the Bekenstein-Hawking formula. The result is also shown to be generically independent of any specific value of the Immirzi parameter.

  12. Bimodal condensation silicone elastomers as dielectric elastomers

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

    as well as high electrical and mechanical breakdown strengths. [1] Most model elastomers are prepared by an end-linking process using a crosslinker with a certain functionality ƒ and a linear polymer with functional groups in both ends, and the resulting networks are so-called unimodal networks where...... unimodal refers to that there is one polymer only in the system. As an alternative to unimodal networks there are the bimodal networks where two polymers with significantly different molecular weights are mixed with one crosslinker. [2]Silicone rubber can be divided into condensation type and addition type...... elastomers were prepared by mixing different mass ratios (9:1, 8:2, 7:3, 6:4, 5:5, 4:6) between long polydimethylsiloxane (PDMS) chains and short PDMS chains. The resulting elastomers were investigated with respect to their rheology, dielectric properties, tensile strength, electrical breakdown, as well...

  13. Fidelity of a Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Liu Jie; Zhang Chuanwei; Niu Qian; Li Baowen

    2006-01-01

    We investigate fidelity for the quantum evolution of a Bose-Einstein condensate and reveal its general property with a simple model. We find the fidelity decay with time in various ways depending on the form of initial states as well as on mean-field dynamics. When the initial state is a coherent state, the fidelity decays with time in the ways of exponential, Gaussian, and power-law, having a close relation to the classical mean-field dynamics. With the initial state prepared as a maximally entangled state, we find the behavior of fidelity has no classical correspondence and observe a novel behavior of the fidelity: periodic revival, where the period is inversely proportional to the number of bosons and the perturbation strength. An experimental observation of the fidelity decay is suggested

  14. Yield stress materials in soft condensed matter

    Science.gov (United States)

    Bonn, Daniel; Denn, Morton M.; Berthier, Ludovic; Divoux, Thibaut; Manneville, Sébastien

    2017-07-01

    A comprehensive review is presented of the physical behavior of yield stress materials in soft condensed matter, which encompasses a broad range of materials from colloidal assemblies and gels to emulsions and non-Brownian suspensions. All these disordered materials display a nonlinear flow behavior in response to external mechanical forces due to the existence of a finite force threshold for flow to occur: the yield stress. Both the physical origin and rheological consequences associated with this nonlinear behavior are discussed and an overview is given of experimental techniques available to measure the yield stress. Recent progress is discussed concerning a microscopic theoretical description of the flow dynamics of yield stress materials, emphasizing, in particular, the role played by relaxation time scales, the interplay between shear flow and aging behavior, the existence of inhomogeneous shear flows and shear bands, wall slip, and nonlocal effects in confined geometries.

  15. Holographic duality in condensed matter physics

    CERN Document Server

    Zaanen, Jan; Sun, Ya-Wen; Schalm, Koenraad

    2015-01-01

    A pioneering treatise presenting how the new mathematical techniques of holographic duality unify seemingly unrelated fields of physics. This innovative development morphs quantum field theory, general relativity and the renormalisation group into a single computational framework and this book is the first to bring together a wide range of research in this rapidly developing field. Set within the context of condensed matter physics and using boxes highlighting the specific techniques required, it examines the holographic description of thermal properties of matter, Fermi liquids and superconductors, and hitherto unknown forms of macroscopically entangled quantum matter in terms of general relativity, stars and black holes. Showing that holographic duality can succeed where classic mathematical approaches fail, this text provides a thorough overview of this major breakthrough at the heart of modern physics. The inclusion of extensive introductory material using non-technical language and online Mathematica not...

  16. PAC Spectrometer for Condensed Matter Investigation

    CERN Document Server

    Brudanin, V B; Kochetov, O I; Korolev, N A; Milanov, M; Ostrovsky, I V; Pavlov, V N; Salamatin, A V; Timkin, V V; Velichkov, A I; Fomicheva, L N; Tsvyaschenko, A V; Akselrod, Z Z

    2005-01-01

    A four-detector spectrometer of perturbed angular $\\gamma \\gamma $ correlations is developed for investigation of hyperfine interactions in condensed matter. It allows measurements with practically any types of detectors. A unique circuit design involving a specially developed Master PAC unit combined with a computer allows a substantially higher efficiency, reduced setup time and simpler operation in comparison with traditional PAC spectrometers. A cryostat and a high-temperature oven allow measurements in the temperature range from 120 to 1300 K. An encased electromagnet makes it possible to generate a magnetic field up to 2 T on a sample. The measurement system includes a press with a specially designed high-pressure chamber allowing on-line PAC measurements in samples under pressure up to 60 GPa.

  17. Gauge field condensation in geometric quantum chromodynamics

    International Nuclear Information System (INIS)

    Guendelman, E.I.

    1991-09-01

    In odd number of dimensions, it is possible to construct general covariant gauge theories, where the metric is not an independent variable, but local function of the gauge fields. Starting from standardly defined gauge theory, upon functional integration of some variables, we could end up with such moodels. For models with SU(2) and SU(3) symmetry in three dimensions, gauge field condensation take place in the vacuum, which is nevertheless homogeneous and isotropic up to a gauge transformation, provided the space is flat. Introducing Higgs fields that spontaneously break the gauge symmetry, we get a breakdown of the homogenity and isotropy of the vacuum. Finally, we discuss how some of this ideas can be generalized to four and other even dimensions. (author)

  18. Magnetic polarons in a nonequilibrium polariton condensate

    Science.gov (United States)

    Mietki, Paweł; Matuszewski, Michał

    2017-09-01

    We consider a condensate of exciton polaritons in a diluted magnetic semiconductor microcavity. Such a system may exhibit magnetic self-trapping in the case of sufficiently strong coupling between polaritons and magnetic ions embedded in the semiconductor. We investigate the effect of the nonequilibrium nature of exciton polaritons on the physics of the resulting self-trapped magnetic polarons. We find that multiple polarons can exist at the same time, and we derive a critical condition for self-trapping that is different from the one predicted previously in the equilibrium case. Using the Bogoliubov-de Gennes approximation, we calculate the excitation spectrum and provide a physical explanation in terms of the effective magnetic attraction between polaritons, mediated by the ion subsystem.

  19. Edge effects on water droplet condensation.

    Science.gov (United States)

    Medici, Marie-Gabrielle; Mongruel, Anne; Royon, Laurent; Beysens, Daniel

    2014-12-01

    In this study we investigate the effect of geometrical or thermal discontinuities on the growth of water droplets condensing on a cooled substrate. Edges, corners, and cooled and noncooled boundaries can have a strong effect on the vapor concentration profile and mass diffusion around the drops. In comparison to growth in a pattern where droplets have to compete to catch vapor, which results in a linear water concentration profile directed perpendicularly to the substrate, droplets near discontinuities can get more vapor (outer edges, corners), resulting in faster growth or less vapor (inner edges), giving lower growth. When the cooling heat flux limits growth instead of mass diffusion (substrate with low thermal conductivity, strong heat exchange with air), edge effects can be canceled. In certain cases, growth enhancement can reach nearly 500% on edges or corners.

  20. Characterization of DWPF recycle condensate materials

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Adamson, D. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); King, W. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-04-01

    A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to understand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF the Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here.