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Sample records for aldol condensation products

  1. Iron-catalyzed vinylogous aldol condensation of Biginelli products and its application toward pyrido[4,3-d]pyrimidinones.

    PubMed

    Zhang, Lianqiang; Zhang, Zhiguo; Liu, Qingfeng; Liu, Tongxin; Zhang, Guisheng

    2014-03-01

    A novel iron-catalyzed vinylogous aldol condensation of Biginelli products with aryl aldehydes has been developed for the syntheses of potential bioactive (E)-6-arylvinyl-dihydropyrimidin-2(1H)-ones. These materials are valuable synthetic precursors to drug-like pyrido[4,3-d]pyrimidine derivatives. The amide group at the 5-position of the dihydropyrimidin-2(1H)-ones played an important role in the vinylogous aldol condensation reaction. PMID:24517724

  2. Studies on self-assembly phenomena of hydrophilization of microporous polypropylene membrane by acetone aldol condensation products: New separator for high-power alkaline batteries

    NASA Astrophysics Data System (ADS)

    Ciszewski, Aleksander; Rydzyńska, Bożena

    Commercial hydrophobic polypropylene (PP) membranes were modified by a novel chemical method. This procedure consists of two steps. In the first step, the virgin hydrophobic PP membrane is saturated with acetone; in the second step, the filled membrane is dipped in aqueous KOH solution (d = 1.28 g cm -3), i.e. in the electrolyte typical for the nickel-cadmium cell. This two-step procedure starts the aldol condensation process of acetone and its products accumulated and adsorbed onto walls of micropores make the membrane hydrophilic. The presented method provided the hydrophilic PP membrane, persistent and soaked with KOH solution with electrolytic resistance of 23-29 mΩ cm 2. This result was compared with the data obtained with commercial hydrophilic membranes: Celgard 3501 and Cellophane. The aldol condensation process of acetone was monitored using the HPLC-ES-MS technique, and modified PP membranes were evaluated by FT-IR and SEM measurements. With the above-mentioned membrane as a separator, nickel-cadmium cells showed good high-rate performance.

  3. Mineral catalysis of a potentially prebiotic aldol condensation

    NASA Technical Reports Server (NTRS)

    De Graaf, R. M.; Visscher, J.; Xu, Y.; Arrhenius, G.; Schwartz, A. W.

    1998-01-01

    Minerals may have played a significant role in chemical evolution. In the course of investigating the chemistry of phosphonoacetaldehyde (PAL), an analogue of glycolaldehyde phosphate, we have observed a striking case of catalysis by the layered hydroxide mineral hydrotalcite ([Mg2Al(OH)6][Cl.nH2O]). In neutral or moderately basic aqueous solutions, PAL is unreactive even at a concentration of 0.1 M. In the presence of a large excess of NaOH (2 M), the compound undergoes aldol condensation to produce a dimer containing a C3-C4 double-bond. In dilute neutral solutions and in the presence of the mineral, however, condensation takes place rapidly, to produce a dimer which is almost exclusively the C2-C3 unsaturated product.

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

    ERIC Educational Resources Information Center

    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…

  5. Aldol Condensation Products and Polyacetals in Organic Films Formed from Reactions of Propanal in Sulfuric Acid at Upper Troposphere/Lower Stratosphere (UT/LS) Aerosol Acidities

    NASA Astrophysics Data System (ADS)

    Bui, J. V. H.; Perez-Montano, S.; Li, E. S. W.; Nelson, T. E.; Ha, K. T.; Leong, L.; Iraci, L. T.; Van Wyngarden, A. L.

    2015-12-01

    Aerosols in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt. %) which is highly reflective towards UV and visible radiation. However, airborne measurements have shown that these particles may also contain a significant amount of organic material. Experiments combining organics (propanal, glyoxal and/or methylglyoxal) with sulfuric acid at concentrations typical of UT/LS aerosols produced highly colored surface films (and solutions) that have the potential to impact chemical, optical and/or cloud-forming properties of aerosols. In order to assess the potential for such films to impact aerosol chemistry or climate properties, experiments were performed to identify the chemical processes responsible for film formation. Surface films were analyzed via Attenuated Total Reflectance-FTIR and Nuclear Magnetic Resonance spectroscopies and are shown to consist primarily of aldol condensation products and cyclic and linear polyacetals, the latter of which are likely responsible for separation from the aqueous phase.

  6. Synthesis and Characterization of Aldol Condensation Products from Unknown Aldehydes and Ketones: An Inquiry-Based Experiment in the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Angelo, Nicholas G.; Henchey, Laura K.; Waxman, Adam J.; Canary, James W.; Arora, Paramjit S.; Wink, Donald

    2007-01-01

    An experiment for the undergraduate chemistry laboratory in which students perform the aldol condensation on an unknown aldehyde and an unknown ketone is described. The experiment involves the use of techniques such as TLC, column chromatography, and recrystallization, and compounds are characterized by [to the first power]H NMR, GC-MS, and FTIR.…

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

    PubMed

    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. PMID:24038987

  8. Molecular Dynamics Simulations of Aldol Condensation Catalyzed by Alkylamine-Functionalized Crystalline Silica Surfaces.

    PubMed

    Kim, Ki Chul; Moschetta, Eric G; Jones, Christopher W; Jang, Seung Soon

    2016-06-22

    Molecular dynamics simulations are performed to investigate the cooperatively catalyzed aldol condensation between acetone and 4-nitrobenzaldehyde on alkylamine (or alkylenamine)-grafted silica surfaces, focusing on the mechanism of the catalytic activation of the acetone and 4-nitrobenzaldehyde by the acidic surface silanols followed by the nucleophilic attack of the basic amine functional group toward the activated reactant. From the analysis of the correlations between the catalytically active acid-base sites and reactants, it is concluded that the catalytic cooperativity of the acid-base pair can be affected by two factors: (1) the competition between the silanol and the amine (or enamine) to form a hydrogen bond with a reactant and (2) the flexibility of the alkylamine (or alkylenamine) backbone. Increasing the flexibility of the alkylamine facilitates the nucleophilic attack of the amine on the reactants. From the molecular dynamics simulations, it is found that C3 propylamine and C4 butylamine linkers exhibit the highest probability of reaction, which is consistent with the experimental observation that the activity of the aldol reaction on mesoporous silica depends on the length of alkylamine grafted on the silica surface. This simulation work serves as a pioneering study demonstrating how the molecular simulation approach can be successfully employed to investigate the cooperative catalytic activity of such bifunctional acid-base catalysts.

  9. Stereodefined Acyclic Polysubstituted Silyl Ketene Aminals: Asymmetric Formation of Aldol Products with Quaternary Carbon Stereocenters.

    PubMed

    Nairoukh, Zackaria; Marek, Ilan

    2015-11-23

    The regio- and stereoselective formation of stereodefined polysubstituted silyl ketene aminals is easily achieved through selective combined carbometalation-oxidation-silylation reactions. These substrates are ideal candidates for Mukaiyama aldol reactions with aliphatic aldehydes as they give the aldol products with a quaternary carbon stereocenter α to the carbonyl groups in outstanding diastereoselectivities. PMID:26448575

  10. Stereodefined Acyclic Polysubstituted Silyl Ketene Aminals: Asymmetric Formation of Aldol Products with Quaternary Carbon Stereocenters.

    PubMed

    Nairoukh, Zackaria; Marek, Ilan

    2015-11-23

    The regio- and stereoselective formation of stereodefined polysubstituted silyl ketene aminals is easily achieved through selective combined carbometalation-oxidation-silylation reactions. These substrates are ideal candidates for Mukaiyama aldol reactions with aliphatic aldehydes as they give the aldol products with a quaternary carbon stereocenter α to the carbonyl groups in outstanding diastereoselectivities.

  11. Sequential aldol condensation-transition metal-catalyzed addition reactions of aldehydes, methyl ketones, and arylboronic acids.

    PubMed

    Liao, Yuan-Xi; Xing, Chun-Hui; Israel, Matthew; Hu, Qiao-Sheng

    2011-04-15

    Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step.

  12. Convergent fabrication of a nanoporous two-dimensional carbon network from an aldol condensation on metal surfaces

    NASA Astrophysics Data System (ADS)

    Landers, John; Chérioux, Frédéric; De Santis, Maurizio; Bendiab, Nedjma; Lamare, Simon; Magaud, Laurence; Coraux, Johann

    2014-12-01

    We report a convergent surface polymerization reaction scheme on Au(111), based on a triple aldol condensation, yielding a carbon-rich, covalent nanoporous two-dimensional network. The reaction is not self-poisoning and proceeds up to a full surface coverage. The deposited precursor molecules 1, 3, 5-tri(4’-acetylphenyl) first form supramolecular assemblies that are converted to the porous covalent network upon heating. The formation and structure of the network and of the intermediate steps are studied with scanning tunneling microscopy, Raman spectroscopy and density functional theory.

  13. Synthesis of dibenzoxepine lactams via a Cu-catalyzed one-pot etherification/aldol condensation cascade reaction: application toward the total synthesis of aristoyagonine.

    PubMed

    Lim, Hye Sun; Choi, Young Lok; Heo, Jung-Nyoung

    2013-09-20

    A general synthesis of dibenzoxepine lactams has been developed using a one-pot Cu-catalyzed etherification/aldol condensation cascade reaction. The reaction of 4-hydroxyisoindolin-1-one with a wide range of 2-bromobenzaldehydes in the presence of a copper catalyst provided various aristoyagonine derivatives in good yields. PMID:24000941

  14. Improvement on the catalytic performance of Mg-Zr mixed oxides for furfural-acetone aldol condensation by supporting on mesoporous carbons.

    PubMed

    Faba, Laura; Díaz, Eva; Ordóñez, Salvador

    2013-03-01

    A new procedure for improving the performance of the most common catalysts used in aqueous-phase aldol condensation (Mg-Zr mixed oxides) reactions is presented. This reaction is of interest for upgrading carbohydrate feedstocks. The procedure involves supporting Mg-Zr oxides on non-microporous carbonaceous materials, such as carbon nanofibers (CNFs) or high-surface-area graphites (HSAGs), using either incipient wetness or coprecipitation procedures. The use of HSAGs together with the coprecipitation method provides the best performance. Results obtained for the cross-condensation of acetone and furfural at 323 K reveal that the catalyst performance is greatly improved compared to the bulk oxides (96.5 % conversion vs. 81.4 % with the bulk oxide; 87.8 % selectivity for C13 and C8 adducts vs. 76.2 % with the bulk oxide). This difference is even more prominent in terms of rates per catalytically active basic site (four and seven times greater for C8 and C13 adducts, respectively). The improved performance is explained in terms of a more appropriate basic site distribution and by greater interaction of the reactants with the carbon surface. In addition, deactivation behavior of the catalyst is improved by tuning the morphology of the carbonaceous support. An important enhancement of the catalytic stability can be obtained selecting a HSAG with an appropriate pore diameter. With HSAG100 the activity decreased by less than 20 % between successive reaction cycles and the selectivity for the condensation products remained almost unaltered. The decrease is greater than 80 % for the bulk oxides tested at these conditions, with important increases in the selectivity for by-product formation. PMID:23362138

  15. Asymmetric, Three-Component, One-Pot Synthesis of Spiropyrazolones and 2,5-Chromenediones from Aldol Condensation/NHC-Catalyzed Annulation Reactions.

    PubMed

    Wang, Lei; Li, Sun; Chauhan, Pankaj; Hack, Daniel; Philipps, Arne R; Puttreddy, Rakesh; Rissanen, Kari; Raabe, Gerhard; Enders, Dieter

    2016-04-01

    A novel one-pot, three-component diastereo- and enantioselective synthesis of spiropyrazolones has been developed involving the aldol condensation of an enal to generate α,β-unsaturated pyrazolones, which react with a second equivalent of enal through an N-heterocyclic carbene (NHC)-catalyzed [3+2] annulation. The desired spirocyclopentane pyrazolones are obtained in moderate to good yields and good to excellent stereoselectivities. Alternatively, starting from cyclic 1,3-diketones, 2,5-chromenediones are available through [2+4] annulation.

  16. Asymmetric, Three-Component, One-Pot Synthesis of Spiropyrazolones and 2,5-Chromenediones from Aldol Condensation/NHC-Catalyzed Annulation Reactions.

    PubMed

    Wang, Lei; Li, Sun; Chauhan, Pankaj; Hack, Daniel; Philipps, Arne R; Puttreddy, Rakesh; Rissanen, Kari; Raabe, Gerhard; Enders, Dieter

    2016-04-01

    A novel one-pot, three-component diastereo- and enantioselective synthesis of spiropyrazolones has been developed involving the aldol condensation of an enal to generate α,β-unsaturated pyrazolones, which react with a second equivalent of enal through an N-heterocyclic carbene (NHC)-catalyzed [3+2] annulation. The desired spirocyclopentane pyrazolones are obtained in moderate to good yields and good to excellent stereoselectivities. Alternatively, starting from cyclic 1,3-diketones, 2,5-chromenediones are available through [2+4] annulation. PMID:26864437

  17. The Aldol Addition and Condensation: The Effect of Conditions on Reaction Pathway

    ERIC Educational Resources Information Center

    Crouch, R. David; Richardson, Amie; Howard, Jessica L.; Harker, Rebecca L.; Barker, Kathryn H.

    2007-01-01

    The reaction of a ketone and an aldehyde in aqueous Na[subscript 2]CO[subscript 2] is described. This experiment is performed in the absence of strong bases or organic solvents and offers the opportunity for students to observe the critical role that reaction temperature and base strength have in determining the product of the base-mediated…

  18. The effect of the distance between acidic site and basic site immobilized on mesoporous solid on the activity in catalyzing aldol condensation

    SciTech Connect

    Yu Xiaofang; Yu Xiaobo; Wu Shujie; Liu Bo; Liu Heng; Guan Jingqi; Kan Qiubin

    2011-02-15

    Acid-base bifunctional heterogeneous catalysts containing carboxylic and amine groups, which were immobilized at defined distance from one another on the mesoporous solid were synthesized by immobilizing lysine onto carboxyl-SBA-15. The obtained materials were characterized by X-ray diffraction (XRD), N{sub 2} adsorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron micrographs (SEM), transmission electron micrographs (TEM), elemental analysis, and back titration. Proximal-C-A-SBA-15 with a proximal acid-base distance was more active than maximum-C-A-SBA-15 with a maximum acid-base distance in aldol condensation reaction between acetone and various aldehydes. It appears that the distance between acidic site and basic site immobilized on mesoporous solid should be an essential factor for catalysis optimization. -- Graphical abstract: Proximal-C-A-SBA-15 with a proximal acid-base distance and maximum-C-A-SBA-15 with a maximum acid-base distance were synthesized by immobilizing lysine onto carboxyl-SBA-15. Display Omitted Research highlights: {yields} Proximal-C-A-SBA-15 with a proximal acid-base distance. {yields} Maximum-C-A-SBA-15 with a maximum acid-base distance. {yields} Compared to maximum-C-A-SBA-15, proximal-C-A-SBA-15 was more active toward aldol condensation reaction between acetone and various aldehydes.

  19. Organocatalytic enantioselective Michael-Michael-Michael-aldol condensation reactions: control of five stereocenters in a quadruple-cascade asymmetric synthesis of highly functionalized hexahydrophenanthrenes.

    PubMed

    Raja, Arun; Hong, Bor-Cherng; Lee, Gene-Hsiang

    2014-11-01

    A cascade organocatalysis has been developed for the enantioselective synthesis of a highly functionalized hexahydrophenanthrene-2-carbaldehyde containing five contiguous stereogenic centers with high diastereoselectivity and high enantioselectivity (>99% ee). The one-pot method comprises a cascade of organocatalytic Michael-Michael-Michael-aldol reactions of 2-methyl-1,5-dinitro-3-((E)-2-nitrovinyl)benzene and α,β-unsaturated aldehydes (e.g., cinnamaldehyde). The structure and absolute configuration of a product were confirmed by X-ray analysis of an appropriate derivative.

  20. Chondrules as condensation products

    NASA Technical Reports Server (NTRS)

    Wood, J. A.; Mcsween, H. Y., Jr.

    1977-01-01

    The formation of meteoritic chondrules via condensation from the primordial solar nebula is discussed. Chondrule formation in regions where the gas/dust ratio was enhanced, and where transient high energy events heated the gas and temporarily vaporized the dust, is advocated. The observed diversity of chondrule types can be understood as resulting from local variations in the initial gas/dust proportions and other parameters.

  1. Bifunctional Brønsted Base Catalyzes Direct Asymmetric Aldol Reaction of α-Keto Amides.

    PubMed

    Echave, Haizea; López, Rosa; Palomo, Claudio

    2016-03-01

    The first enantioselective direct cross-aldol reaction of α-keto amides with aldehydes, mediated by a bifunctional ureidopeptide-based Brønsted base catalyst, is described. The appropriate combination of a tertiary amine base and an aminal, and urea hydrogen-bond donor groups in the catalyst structure promoted the exclusive generation of the α-keto amide enolate which reacted with either non-enolizable or enolizable aldehydes to produce highly enantioenriched polyoxygenated aldol adducts without side-products resulting from dehydration, α-keto amide self-condensation, aldehyde enolization, and isotetronic acid formation.

  2. Bifunctional Brønsted Base Catalyzes Direct Asymmetric Aldol Reaction of α-Keto Amides.

    PubMed

    Echave, Haizea; López, Rosa; Palomo, Claudio

    2016-03-01

    The first enantioselective direct cross-aldol reaction of α-keto amides with aldehydes, mediated by a bifunctional ureidopeptide-based Brønsted base catalyst, is described. The appropriate combination of a tertiary amine base and an aminal, and urea hydrogen-bond donor groups in the catalyst structure promoted the exclusive generation of the α-keto amide enolate which reacted with either non-enolizable or enolizable aldehydes to produce highly enantioenriched polyoxygenated aldol adducts without side-products resulting from dehydration, α-keto amide self-condensation, aldehyde enolization, and isotetronic acid formation. PMID:26835655

  3. Enantioselective aldol reactions with masked fluoroacetates

    NASA Astrophysics Data System (ADS)

    Saadi, Jakub; Wennemers, Helma

    2016-03-01

    Despite the growing importance of organofluorines as pharmaceuticals and agrochemicals, the stereoselective introduction of fluorine into many prominent classes of natural products and chemotherapeutic agents is difficult. One long-standing unsolved challenge is the enantioselective aldol reaction of fluoroacetate to enable access to fluorinated analogues of medicinally relevant acetate-derived compounds, such as polyketides and statins. Herein we present fluoromalonic acid halfthioesters as biomimetic surrogates of fluoroacetate and demonstrate their use in highly stereoselective aldol reactions that proceed under mild organocatalytic conditions. We also show that the methodology can be extended to formal aldol reactions with fluoroacetaldehyde and consecutive aldol reactions. The synthetic utility of the fluorinated aldol products is illustrated by the synthesis of a fluorinated derivative of the top-selling drug atorvastatin. The results show the prospects of the method for the enantioselective introduction of fluoroacetate to access a wide variety of highly functionalized fluorinated compounds.

  4. Synthesis of two subunits of the macrolide domain of the immunosuppressive agent sanglifehrin a and assembly of a macrolactone precursor. application of masamune anti-aldol condensation.

    PubMed

    Suttisintong, Khomson; White, James D

    2015-02-20

    Asymmetric anti-aldol coupling of a norephedrine-derived ester with an α-chiral aldehyde was used to synthesize a carboxylic acid representing the C13-C19 segment of the macrocyclic domain present in the immunosuppressive agent sanglifehrin A. Felkin addition set configuration at the C14-C17 stereotetrad in this unit in which hydroxyl functions at C15 and C17 were masked as an internal ketal. The carboxyl group of this segment was coupled to the N-terminus of the tripeptide portion (C1-N12) of sanglifehrin A macrolactone to assemble the C1-C19 domain. Synthesis of the C20-C25 subunit of sanglifehrin A containing a (23S) alcohol was completed via asymmetric allylation of (E)-3-iodo-2-methylprop-2-enal followed by oxidative cleavage of the terminal vinyl appendage and a Takai olefination with pinacol dichloromethylboronate. Esterification of this alcohol with a C1-C19 carboxylic acid furnished an open C1-C25 macrolactone precursor, but this substance failed to undergo macrocyclization via intramolecular Suzuki-Miyaura coupling. PMID:25584782

  5. Computational elucidation of the origins of reactivity and selectivity in non-aldol aldol rearrangements of cyclic epoxides.

    PubMed

    Wang, Hao; Houk, K N; Allen, Damian A; Jung, Michael E

    2011-06-17

    The non-aldol aldol reaction of the isomeric epoxy silyl ethers is controlled by the conformation of the transition states leading to an internal hydride shift. One isomer rearranges to the β-silyloxy ketone whereas the other isomer gives a β-elimination product. Theoretical calculations show that the substrates with substituents that favor the formation of the chairlike transition state rearrange normally while those that do not undergo elimination instead. PMID:21568276

  6. Pd/NbOPO₄ multifunctional catalyst for the direct production of liquid alkanes from aldol adducts of furans.

    PubMed

    Xia, Qi-Neng; Cuan, Qian; Liu, Xiao-Hui; Gong, Xue-Qing; Lu, Guan-Zhong; Wang, Yan-Qin

    2014-09-01

    Great efforts have been made to convert renewable biomass into transportation fuels. Herein, we report the novel properties of NbO(x)-based catalysts in the hydrodeoxygenation of furan-derived adducts to liquid alkanes. Excellent activity and stability were observed with almost no decrease in octane yield (>90% throughout) in a 256 h time-on-stream test. Experimental and theoretical studies showed that NbO(x) species play the key role in C-O bond cleavage. As a multifunctional catalyst, Pd/NbOPO4 plays three roles in the conversion of aldol adducts into alkanes: 1) The noble metal (in this case Pd) is the active center for hydrogenation; 2) NbO(x) species help to cleave the C-O bond, especially of the tetrahydrofuran ring; and 3) a niobium-based solid acid catalyzes the dehydration, thus enabling the quantitative conversion of furan-derived adducts into alkanes under mild conditions. PMID:25045056

  7. Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles.

    PubMed

    Zhang, Song-Lin; Deng, Zhu-Qin

    2016-07-26

    A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions.

  8. Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles.

    PubMed

    Zhang, Song-Lin; Deng, Zhu-Qin

    2016-07-26

    A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions. PMID:27397647

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

    ERIC Educational Resources Information Center

    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…

  10. Chemical transformations during rectification of products of hydroformylation of propylene

    SciTech Connect

    Kuz'mina, L.S.; Maiorova, L.V.; Kharisov, M.A.

    1988-09-10

    The occurrence of reactions related to losses of the target products, aldehydes and alcohols, was established in continuous rectification of the products of hydroformylation of propylene. The sections of the zone of primary occurrence of the reactions of aldol condensation, formation of acetals, and esterification of butyl alcohols with butyric acids were determined in the rectification column. It was shown that with increase in temperature in the rectification column still the degree of aldehyde and alcohol conversion in the overall rectification system decreases with respect to aldol condensation and acetal formation, while increasing with respect to alcohol esterification.

  11. Aldol reactions of the trans-o-hydroxybenzylidenepyruvate hydratase-aldolase (tHBP-HA) from Pseudomonas fluorescens N3.

    PubMed

    Sello, Guido; Di Gennaro, Patrizia

    2013-08-01

    In this paper, a recombinant trans-o-hydroxybenzylidenepyruvate hydratase-aldolase (tHBP-HA) of Pseudomonas fluorescens N3 was used as a new catalyst for aldol condensation reactions. The reaction of some aldehydes with a different electronic activation catalyzed by tHBP-HA is presented and discussed together with some hints on the product structure. The enzyme is strictly pyruvate-dependent but uses different aldehydes as acceptors. The structure of the products is highly dependent on the electronic characteristics of the aldehyde. The results are interesting for both their synthetic importance and the mechanism of the formation of the products. Not only the products obtained and the recognition power are reported, but also some characteristics of its mechanism are analyzed. The results clearly show that the enzyme is efficiently prepared, purified, and stored, that it recognizes many different substrates, and that the products depend on the substrate electronic nature.

  12. Tandem Catalysis of an Aldol-'Click' Reaction System within a Molecular Hydrogel.

    PubMed

    Araújo, Marco; Muñoz Capdevila, Iván; Díaz-Oltra, Santiago; Escuder, Beatriu

    2016-01-01

    A heterogeneous supramolecular catalytic system for multicomponent aldol-'click' reactions is reported. The copper(I) metallohydrogel functionalized with a phenyltriazole fragment was able to catalyze the multicomponent reaction between phenylacetylene, p-nitrobenzaldehyde, and an azide containing a ketone moiety, obtaining the corresponding aldol products in good yields. A possible mechanistic pathway responsible for this unexpected catalytic behavior has been proposed. PMID:27338313

  13. Mukaiyama Aldol Reactions in Aqueous Media

    PubMed Central

    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 beneficial effects in the presence of water will be deepened through the brilliant examples collected in this review. 1 Introduction 2 Rate Enhancement by Water in the Mukaiyama Aldol Reaction 3 Lewis Acid Catalysis in Aqueous or Organic Solvents 3.1 Water-Compatible Lewis Acids 4 Lewis-Base Catalysis in Aqueous or Organic Solvents 5 The Mukaiyama Aldol Reactions in 100% Water 6 Asymmetric Catalysts in Aqueous Media and Water 7 Conclusions and Perspective PMID:24971045

  14. The Direct Catalytic Asymmetric Aldol Reaction

    PubMed Central

    Brindle, Cheyenne S.

    2013-01-01

    Asymmetric aldol reactions are a powerful method for the construction of carbon-carbon bonds in an enantioselective fashion. Historically this reaction has been performed in a stoichiometric fashion to control the various aspects of chemo-, diastereo-, regio- and enantioselectivity, however, a more atom economical approach would unite high selectivity with the use of only a catalytic amount of a chiral promoter. This critical review documents the development of direct catalytic asymmetric aldol methodologies, including organocatalytic and metal-based strategies. New methods have improved the reactivity, selectivity and substrate scope of the direct aldol reaction and enabled the synthesis of complex molecular targets PMID:20419212

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

    PubMed

    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.

  16. Condensation of water vapor and carbon dioxide in the jet exhausts of rocket engines: 1. Heterogeneous condensation of combustion products

    NASA Astrophysics Data System (ADS)

    Platov, Yu. V.; Semenov, A. I.; Filippov, B. V.

    2014-01-01

    Condensation of water vapor and carbon dioxide in the jet exhausts of rocket engines during last stages of Proton, Molniya, and Start launchers operating in the upper atmospheric with different types of fuels is considered. Particle heating is taken into account with emission of latent heat of condensation and energy loss due to radiation and heat exchange with combustion products. Using the solution of the heat balance and condensed particle mass equations, the temporal change in the temperature and thickness of the condensate layer is obtained. Practically, no condensation of water vapor and carbon dioxide in the jet exhaust of a Start launcher occurs. In plumes of Proton and Molniya launchers, the condensation of water vapor and carbon dioxide can start at distances of 120-170 m and 450-650 m from the engine nozzle, respectively. In the course of condensation, the thickness of the "water" layer on particles can exceed 100 Å, and the thickness of carbon dioxide can exceed 60 Å.

  17. Novel condensation products having high activity to insolubilize proteins and protein-insolubilized products

    SciTech Connect

    Krasnobajew, V.; Boeniger, R.

    1980-01-01

    According to the invention a substantially more active product with respect to the fixing or insolubilization pf proteins, including enzymes, is obtained when 1,3 phenylenediamine is condensed with glutardialdehyde. One application of the process is the enzymatic hydrolysis of lactose in milk products by lactase.

  18. Developing novel organocatalyzed aldol reactions for the enantioselective synthesis of biologically active molecules

    PubMed Central

    Bhanushali, Mayur; Zhao, Cong-Gui

    2011-01-01

    Aldol reaction is one of the most important methods for the formation of carbon-carbon bonds. Because of its significance and usefulness, asymmetric versions of this reaction have been realized with different approaches in the past. Over the last decade, the area of organocatalysis has made significant progresses. As one of most studied reactions in organocatalyses, organocatalyzed aldol reaction has emerged as a powerful tool for the synthesis of a large number of useful products in optically enriched forms. In this review, we summarize our efforts on the development of novel organocatalyzed aldol reactions for the enantioselective synthesis of biological active molecules. Literatures closely related to our studies are also covered. PMID:21918584

  19. Binaphthyl-based chiral bifunctional organocatalysts for water mediated asymmetric List-Lerner-Barbas aldol reactions.

    PubMed

    Ashokkumar, Veeramanoharan; Chithiraikumar, Chinnadurai; Siva, Ayyanar

    2016-10-14

    Novel binaphthyl-based chiral bifunctional organocatalysts were designed, synthesized and successfully applied to the asymmetric List-Lerner-Barbas aldol reaction in the presence of water. These organocatalysts were found to be effective catalysts for the reactions of symmetrical, unsymmetrical and cyclic ketones with different aldehydes to give the corresponding aldol products with higher yields (up to 98%) and very good ee's up to 99%. The catalytic system leads to higher yields and selectivities than the previously reported well-known proline based organocatalysts. In addition to the effect of solvent, additives, catalyst concentration, temperature and the substrate scope of the reactions were also investigated. PMID:27604169

  20. Ultraforward particle production from color glass condensate and Lund fragmentation

    NASA Astrophysics Data System (ADS)

    Albacete, Javier L.; Guerrero Rodríguez, Pablo; Nara, Yasushi

    2016-09-01

    We present an analysis of data on single inclusive pion production measured by the LHCf Collaboration in high-energy proton-proton and proton-nucleus at ultraforward rapidities, 8.8 ≤y ≤10.8 . We also analyze forward RHIC data for calibration purposes. Our analysis relies on the use of a Monte Carlo event generator that combines a perturbative description of the elementary scattering process at partonic level based on the hybrid formalism of the color glass condensate with an implementation of hadronization in the framework of the Lund string fragmentation model. This procedure allows us to reach values of the momenta of the produced particles as low as detected experimentally, pt˜0.1 GeV . We achieve a good description of single inclusive spectra of charged particles and neutral pions at the RHIC and the LHC, respectively, and nuclear modification factors for proton-lead collisions at the LHC. Our results add evidence to the idea that particle production in the domain of a very small Bjorken x is dominated by the saturation effects encoded in the unintegrated gluon distribution of the target. With forward particle production being of key importance in the development of air showers, we stress that this approach allows for a theoretically controlled extrapolation of our results to the scale of ultra-high-energy cosmic rays, thus serving as the starting point for future works on this topic.

  1. α-Hydroxyallylsilanes as propionaldehyde enolate equivalents and their use toward iterative aldol reactions.

    PubMed

    Ruiz, Johal; Murthy, Akondi Srirama; Roisnel, Thierry; Chandrasekhar, Srivari; Grée, René

    2015-02-20

    Smooth and efficient reaction conditions have been found for the transformation of protected β-hydroxyacylsilanes into the corresponding aldehydes. This opens a new route to iterative aldol reactions, and it has been used for the synthesis of fragments of several bioactive natural products. PMID:25636066

  2. Chiral condensate in the Schwinger model with matrix product operators

    NASA Astrophysics Data System (ADS)

    Bañuls, Mari Carmen; Cichy, Krzysztof; Jansen, Karl; Saito, Hana

    2016-05-01

    Tensor network (TN) methods, in particular the matrix product states (MPS) ansatz, have proven to be a useful tool in analyzing the properties of lattice gauge theories. They allow for a very good precision, much better than standard Monte Carlo (MC) techniques for the models that have been studied so far, due to the possibility of reaching much smaller lattice spacings. The real reason for the interest in the TN approach, however, is its ability, shown so far in several condensed matter models, to deal with theories which exhibit the notorious sign problem in MC simulations. This makes it prospective for dealing with the nonzero chemical potential in QCD and other lattice gauge theories, as well as with real-time simulations. In this paper, using matrix product operators, we extend our analysis of the Schwinger model at zero temperature to show the feasibility of this approach also at finite temperature. This is an important step on the way to deal with the sign problem of QCD. We analyze in detail the chiral symmetry breaking in the massless and massive cases and show that the method works very well and gives good control over a broad range of temperatures, essentially from zero to infinite temperature.

  3. Direct Access to 6/5/7/5- and 6/7/5/5-Fused Tetracyclic Triterpenoids via Divergent Transannular Aldol Reaction of Lanosterol-Derived Diketone

    PubMed Central

    Ignatenko, Vasily A.; Han, Yong

    2013-01-01

    In an effort to access biologically relevant chemical space, a complex natural product-derived non-symmetrical diketone was prepared as a substrate for divergent transannular aldol reactions. The use of common aldol conditions resulted in predominant syn-addition via pathway a, while the use of alumina provided access to the anti-adduct. Screening of a range of Lewis acids of varying strength unexpectedly resulted in the formation of aldol products with 6/7/5/5-fused molecular skeleton via pathway b. PMID:24161022

  4. Cloud Condensation Nuclei Profile Value-Added Product

    SciTech Connect

    McFarlane, S; Sivaraman, C; Ghan, S

    2012-10-08

    The cloud condensation nuclei (CCN) concentration at cloud base is the most relevant measure of the aerosol that influences droplet formation in clouds. Since the CCN concentration depends on supersaturation, a more general measure of the CCN concentration is the CCN spectrum (values at multiple supersaturations). The CCN spectrum is now measured at the surface at several fixed ARM sites and by the ARM Mobile Facility (AMF), but is not measured at the cloud base. Rather than rely on expensive aircraft measurements for all studies of aerosol effects on clouds, a way to project CCN measurements at the surface to cloud base is needed. Remote sensing of aerosol extinction provides information about the vertical profile of the aerosol, but cannot be directly related to the CCN concentration because the aerosol extinction is strongly influenced by humidification, particularly near cloud base. Ghan and Collins (2004) and Ghan et al. (2006) propose a method to remove the influence of humidification from the extinction profiles and tie the “dry extinction” retrieval to the surface CCN concentration, thus estimating the CCN profile. This methodology has been implemented as the CCN Profile (CCNPROF) value-added product (VAP).

  5. Domino Michael-Michael and Aldol-Aldol Reactions: Diastereoselective Synthesis of Functionalized Cyclohexanone Derivatives Containing Quaternary Carbon Center.

    PubMed

    Ghorai, Manas K; Halder, Sandipan; Das, Subhomoy

    2015-10-01

    A simple strategy for the synthesis of highly functionalized cyclohexanone derivatives containing an all-carbon quaternary center from α-(aryl/alkyl)methylidene-β-keto esters or β-diketones via a K-enolate mediated domino Michael-Michael reaction sequence with moderate to good yield and excellent diastereoselectivity (de > 99%) is described. Interestingly, Li-base mediated reaction of α-arylmethylidene-β-diketones affords functionalized 3,5-dihydroxy cyclohexane derivatives as the kinetically controlled products via a domino aldol-aldol reaction sequence with excellent diastereoselectivity. Li-enolates of the β-keto esters or β-diketones undergo facile domino Michael-Michael reaction with nitro-olefins to afford the corresponding nitrocyclohexane derivatives in good yields and excellent diastereoselectivity (de > 99%). The formation of the products and the observed stereoselectivity were explained by plausible mechanisms and supported by extensive computational study. An asymmetric version of the protocol was explored with (L)-menthol derived nonracemic substrates, and the corresponding nonracemic cyclohexanone derivatives containing an all-carbon quaternary center were obtained with excellent stereoselectivity (de, ee > 99%).

  6. Atmospheric leakage and condensate production in NASA's biomass production chamber. Effect of diurnal temperature cycles

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Drese, John H.; Sager, John C.

    1991-01-01

    A series of tests were conducted to monitor atmospheric leakage rate and condensate production in NASA's Biomass Production Chamber (BPC). Water was circulated through the 64 plant culture trays inside the chamber during the tests but no plants were present. Environmental conditions were set to a 12-hr photoperiod with either a matching 26 C (light)/20 C (dark) thermoperiod, or a constant 23 C temperature. Leakage, as determined by carbon dioxide decay rates, averaged about 9.8 percent for the 26 C/20 C regime and 7.3 percent for the constant 23 C regime. Increasing the temperature from 20 C to 26 C caused a temporary increase in pressure (up to 0.5 kPa) relative to ambient, while decreasing the temperature caused a temporary decrease in pressure of similar magnitude. Little pressure change was observed during transition between 23 C (light) and 23 C (dark). The lack of large pressure events under isothermal conditions may explain the lower leakage rate observed. When only the plant support inserts were placed in the culture trays, condensate production averaged about 37 liters per day. Placing acrylic germination covers over the tops of culture trays reduced condensate production to about 7 liters per day. During both tests, condensate production from the lower air handling system was 60 to 70 percent greater than from the upper system, suggesting imbalances exist in chilled and hot water flows for the two air handling systems. Results indicate that atmospheric leakage rates are sufficiently low to measure CO2 exchange rates by plants and the accumulation of certain volatile contaminants (e.g., ethylene). Control system changes are recommended in order to balance operational differences (e.g., humidity and temperature) between the two halves of the chamber.

  7. Asymmetric Aldol-Tishchenko Reaction of Sulfinimines.

    PubMed

    Foley, Vera M; McSweeney, Christina M; Eccles, Kevin S; Lawrence, Simon E; McGlacken, Gerard P

    2015-11-20

    Methods for the preparation of 1,3-amino alcohols and their derivatives containing two stereogenic centers usually involve a two-step installation of the chiral centers. An aldol-Tishchenko reaction of chiral sulfinimines which involves the first reported reduction of a C═N in this type of reaction is described. Two and even three chiral centers can be installed in one synthetic step, affording anti-1,3-amino alcohols in good diastereo- and enantioselectivity. PMID:26528888

  8. Thermodynamically driven, syn-selective vinylogous aldol reaction of tetronamides.

    PubMed

    Karak, Milandip; Barbosa, Luiz C A; Acosta, Jaime A M; Sarotti, Ariel M; Boukouvalas, John

    2016-06-01

    A stereoselective vinylogous aldol reaction of N-monosubstituted tetronamides with aldehydes is described. The procedure is simple and scalable, works well with both aromatic and aliphatic aldehydes, and affords mainly the corresponding syn-aldol adducts. In many cases, the latter are obtained essentially free of their anti-isomers (dr > 99 : 1) in high yields (70-90%). Experimental and computational studies suggest that the observed diastereoselectivity arises through anti-syn isomer interconversion, enabled by an iterative retro-aldol/aldol reaction.

  9. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.500 Condensed, extracted glutamic acid... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Condensed, extracted glutamic acid...

  10. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.500 Condensed, extracted glutamic acid... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Condensed, extracted glutamic acid...

  11. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.500 Condensed, extracted glutamic acid... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Condensed, extracted glutamic acid...

  12. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.500 Condensed, extracted glutamic acid... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Condensed, extracted glutamic acid...

  13. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.500 Condensed, extracted glutamic acid... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Condensed, extracted glutamic acid...

  14. Nonadiabatic production of spinor condensates with a QUIC trap

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Xu, Zhan; You, Li

    2006-05-01

    A recent experiment [Xiu-Quan Ma et al., Chin. Phys. Lett. 22, 1106 (2005)] reported the observation of a multi-component spinor condensate when the magnetic field of a QUIC trap containing a spin polarized condensate was switched off. Our theoretical study show that this phenomena can be described within a general framework of the nonadiabatic Landau-Zener transition theory. We will discuss the population transfers at the zero field level crossing for this interesting case involving more than two levels, and provide a detailed understanding of the relevant nonadiabatic behavior.

  15. Integrated Rig for the Production of Boron Nitride Nanotubes via the Pressurized Vapor-Condenser Method

    NASA Technical Reports Server (NTRS)

    Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor)

    2014-01-01

    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  16. Integrated rig for the production of boron nitride nanotubes via the pressurized vapor-condenser method

    DOEpatents

    Smith, Michael W; Jordan, Kevin C

    2014-03-25

    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  17. Synthesis of the Cores of Hypocrellin and Shiraiachrome: Diastereoselective 1,8-Diketone Aldol Cyclization

    PubMed Central

    O’Brien, Erin M.; Li, Jingxian; Carroll, Patrick J.

    2009-01-01

    Intramolecular 1,8-diketone aldol reactions were studied as a tool for the construction of the 7-membered rings of hypocrellin and shiraiachrome. Conditions were identified to obtain the relative stereochemistries present in the two natural products with excellent diastereoselectivity. In addition, a nine-membered ring congener, which has yet to be observed in nature, formed with high selectivity when a hindered amine was used in conjunction with silazide bases. PMID:19894740

  18. Torrefaction of almond shells: effects of torrefaction conditions on properties of solid and condensate products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almond shells were torrefied in a fixed bed reactor and their solid and condensate products were collected for analysis. A central composite design and response surface methodology were used to examine effects of torrefaction temperature and time on mass and energy yields of solid products as well a...

  19. Exploring the aldol reaction using catalytic antibodies and "on water" organocatalysts from QM/MM calculations.

    PubMed

    Armacost, Kira; Acevedo, Orlando

    2014-01-01

    The aldol reaction between benzaldehyde and acetone has been investigated using QM/MM Monte Carlo calculations and free-energy perturbation theory to determine the origin of the enhanced rates and enantioselectivities (% ee) derived from an enamine-based catalytic antibody 33F12 and a chiral organocatalyst. Electrostatic stabilization of the general acid/base TyrL36 by TrpH103, SerH100, and AsnL34 enabled the 33F12 active site to exclusively adopt an si-face benzaldehyde orientation for C-C bond formation with the LysH93-enamine. Whereas preorganization was responsible for the exclusive (S)-aldol product in the antibody, the organocatalyst featuring a chiral diphenyl amino alcohol moiety instead derived its preferred (R)-aldol product from an interplay between sterics and electronic stabilization. The si-face benzaldehyde conformation had unfavorable interactions with the organocatalyst in contrast to the re-face. Gas-phase calculations predicted a 73% ee; however, solution boosted the % ee values despite similar reaction geometries. An "on water" environment, defined as a reaction that proceeds in an aqueous organic emulsion, yielded a computed 94% ee (exptl 93% ee) compared to a calculated 87% ee in "neat" acetone (exptl 85% ee). Specific hydrogen bonding between the interfacial waters and an amide oxygen on the catalyst was found to control the % ee. A more compact si-face transition structure reduced solvent accessibility to the amide oxygen with a "closed state" steric barrier compared to an "open state" for the re-face. New insight into the synthetically important aldol reaction and state-of-the-art methodology is presented herein.

  20. Direct Catalytic Enantio- and Diastereoselective Ketone Aldol Reactions of Isocyanoacetates**

    PubMed Central

    delaCampa, Raquel; Ortín, Irene; Dixon, Darren J

    2015-01-01

    A catalytic asymmetric aldol addition/cyclization reaction of unactivated ketones with isocyanoacetate pronucleophiles has been developed. A quinine-derived aminophosphine precatalyst and silver oxide were found to be an effective binary catalyst system and promoted the reaction to afford chiral oxazolines possessing a fully substituted stereocenter with good diastereoselectivities and excellent enantioselectivities. PMID:25735645

  1. Beyond Chemoselectivity: Catalytic Site-Selective Aldolization of Diketones and Exploitation for Enantioselective Alzheimer's Drug Candidate Synthesis.

    PubMed

    Nugent, Thomas C; Najafian, Foad Tehrani; Hussein, Hussein Ali El Damrany; Hussain, Ishtiaq

    2016-09-26

    Site selectivity, differentiating instances of the same functional group type on one substrate, represents a forward-looking theme within chemistry: reduced dependence on protection/deprotection protocols for increased overall yield and step-efficiency. Despite these potential benefits and the expanded tactical advantages afforded to synthetic design, site selectivity remains elusive and especially so for ketone-based substrates. Herein, site-selective intermolecular mono-aldolization has been demonstrated for an array of prochiral 4-keto-substituted cyclohexanones with concomitant regio-, diastereo-, and enantiocontrol. Importantly, the aldol products allow rapid access to molecularly complex ketolactones or keto-1,3-diols, respectively containing three and four stereogenic centers. The reaction conditions are of immediate practical value and general enough to be applicable to other reaction types. These findings are applied in the first enantioselective, formal, synthesis of a leading Alzheimer's research drug, a γ-secretase modulator (GSM), in the highest known yield. PMID:27546719

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

    PubMed

    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. PMID:24692320

  3. Stereocontrolled Synthesis of Syn-β-Hydroxy-α-Amino Acids by Direct Aldolization of Pseudoephenamine Glycinamide

    PubMed Central

    Seiple, Ian B.; Mercer, Jaron A. M.; Sussman, Robin J.; Zhang, Ziyang

    2014-01-01

    β-Hydroxy-α-amino acids figure prominently as chiral building blocks in chemical synthesis, serving as precursors to numerous important medicines. We have developed and here report 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 lithium chloride 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. PMID:24692320

  4. Assessment of natural hydrocarbon bioremediation at two gas condensate production sites

    SciTech Connect

    Barker, G.W.; Raterman, K.T.; Fisher, J.B.; Corgan, J.M.; Trent, G.L.; Brown, D.R.; Sublette, K.L.

    1995-12-31

    Condensate liquids are present in soil and groundwater at two gas production sites in the Denver-Julesburg Basin operated by Amoco. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate endpoint to support a no-intervention decision. Groundwater monitoring and analysis of soil cores strongly suggest that intrinsic bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, Fe(III) reduction, and sulfate reduction.

  5. Rapid Production of Bose-Einstein Condensates at a 1 Hz Rate

    NASA Astrophysics Data System (ADS)

    Farkas, Daniel; Ramirez-Serrano, Jaime; Salim, Evan

    2013-05-01

    The speed at which Bose-Einstein condensates (BECs) can be produced is a key metric for the performance of ultracold-atom inertial sensors, gravimeters, and magnetometers, where production cycle time of ultracold atoms determines sensor bandwidth. Here, we demonstrate production of 87Rb BECs at rates exceeding 1 Hz. Not only can we create a BEC from a hot vapor in less than one second, but we can continuously repeat the process for several cycles. Such speeds are possible because of the short evaporation times that result when atoms are confined in tight traps. In our case, we magnetically trap atoms with an atom chip that seals the top of one of ColdQuanta's RuBECi®vacuum cells. With RF evaporative cooling sequences as short as 450 ms, we attain nearly pure condensates of 2 × 104 atoms. In the future, the apparatus described here will be integrated into a portable system that houses all of the components needed to produce BECs (e.g. lasers, vacuum, electronics, imaging, etc.) in a volume less than 0.3 m3. This work was supported by the Office of Naval Research (SBIR contract N00014-10-C-0282).

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

    PubMed

    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.

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

    PubMed Central

    Delaney, Joshua P.; Henderson, Luke C.

    2011-01-01

    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. PMID:22272120

  8. Stereoselectivity in (Acyloxy)borane-Catalyzed Mukaiyama Aldol Reactions.

    PubMed

    Lee, Joshua M; Zhang, Xin; Norrby, Per-Ola; Helquist, Paul; Wiest, Olaf

    2016-07-01

    The origin of diastereo- and enantioselectivity in a Lewis acid-catalyzed Mukaiyama aldol reaction is investigated using a combination of dispersion corrected DFT calculations and transition state force fields (TSFF) developed using the quantum guided molecular mechanics (Q2MM) method. The reaction proceeds via a closed transition structure involving a nontraditional hydrogen bond that is 3.3 kJ/mol lower in energy than the corresponding open transition structure. The correct prediction of the diastereoselectivity of a Mukaiyama aldol reaction catalyzed by the conformationally flexible Yamamoto chiral (acyloxy) borane (CAB) requires extensive conformational sampling at the transition structure, which is achieved using a Q2MM-derived TSFF, followed by DFT calculations of the low energy conformational clusters. Finally, a conceptual model for the rationalization of the observed diastereo- and enantioselectivity of the reaction using a closed transition state model is proposed. PMID:27247023

  9. Functionalized multi-walled carbon nanotubes in an aldol reaction

    NASA Astrophysics Data System (ADS)

    Chronopoulos, D. D.; Kokotos, C. G.; Karousis, N.; Kokotos, G.; Tagmatarchis, N.

    2015-01-01

    The covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with a proline-based derivative is reported. Initially, MWCNTs were oxidized in order to introduce a large number of carboxylic units on their tips followed by N-tert-butoxycarbonyl-2,2'(ethylenedioxy)bis-(ethylamine) conjugation through an amide bond. Then, a proline derivative bearing a carboxylic terminal moiety at the 4-position was coupled furnishing proline-modified MWCNTs. This new hybrid material was fully characterized by spectroscopic and microscopy means and its catalytic activity in the asymmetric aldol reaction between acetone and 4-nitrobenzaldehyde was evaluated for the first time, showing to proceed almost quantitatively in aqueous media. Furthermore, several amino-modified MWCNTs were prepared and examined in the particular aldol reaction. These new hybrid materials exhibited an enhanced catalytic activity in water, contrasting with the pristine MWCNTs as well as the parent organic molecule, which failed to catalyze the reaction efficiently. Furthermore, the modified MWCNTs proved to catalyze the aldol reaction even after three repetitive cycles. Overall, a green approach for the aldol reaction is presented, where water can be employed as the solvent and modified MWCNTs can be used as catalysts, which can be successfully recovered and reused, while their catalytic activity is retained.The covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with a proline-based derivative is reported. Initially, MWCNTs were oxidized in order to introduce a large number of carboxylic units on their tips followed by N-tert-butoxycarbonyl-2,2'(ethylenedioxy)bis-(ethylamine) conjugation through an amide bond. Then, a proline derivative bearing a carboxylic terminal moiety at the 4-position was coupled furnishing proline-modified MWCNTs. This new hybrid material was fully characterized by spectroscopic and microscopy means and its catalytic activity in the asymmetric aldol reaction

  10. Prebiotic chemistry of phosphonic acids: products derived from phosphonoacetaldehyde in the presence of formaldehyde.

    PubMed

    De Graaf, R M; Visscher, J; Schwartz, A W

    1998-06-01

    Phosphonoacetaldehyde (PAL), a phosphonic acid analogue of glycolaldehyde phosphate, reacts in the presence of formaldehyde under mildly basic conditions to produce several new products. The reaction proceeds in two stages: a fast aldol condensation of formaldehyde with PAL, and a slower reaction to produce products containing two phosphonic acid groups. We report on the derivatization, isolation by means of HPLC and characterization of these compounds. One of the products is of potential interest as a building block for a prebiotic informational polymer. PMID:9611767

  11. Tensor meson production in proton-proton collisions from the color glass condensate

    SciTech Connect

    Fillion-Gourdeau, Francois; Jeon, Sangyong

    2008-05-15

    We compute the inclusive cross section of f{sub 2} tensor-meson production in proton-proton collisions at high energy. We use an effective theory inspired from the tensor-meson dominance hypothesis that couples gluons to f{sub 2} mesons. We compute the differential cross section in the k{sub perpendicular} factorization and in the color glass condensate formalism in the low density regime. We show that the two formalisms are equivalent for this specific observable. Finally, we study the phenomenology of f{sub 2} mesons by comparing theoretical predictions of different parametrizations of the unintegrated gluon distribution function. We find that f{sub 2}-meson production is another observable that can be used to put constraints on these distributions.

  12. Numerical simulation of vortex pyrolysis reactors for condensable tar production from biomass

    SciTech Connect

    Miller, R.S.; Bellan, J.

    1998-08-01

    A numerical study is performed in order to evaluate the performance and optimal operating conditions of vortex pyrolysis reactors used for condensable tar production from biomass. A detailed mathematical model of porous biomass particle pyrolysis is coupled with a compressible Reynolds stress transport model for the turbulent reactor swirling flow. An initial evaluation of particle dimensionality effects is made through comparisons of single- (1D) and multi-dimensional particle simulations and reveals that the 1D particle model results in conservative estimates for total pyrolysis conversion times and tar collection. The observed deviations are due predominantly to geometry effects while directional effects from thermal conductivity and permeability variations are relatively small. Rapid ablative particle heating rates are attributed to a mechanical fragmentation of the biomass particles that is modeled using a critical porosity for matrix breakup. Optimal thermal conditions for tar production are observed for 900 K. Effects of biomass identity, particle size distribution, and reactor geometry and scale are discussed.

  13. Effect of Fodder Tree Species with Condensed Tannin Contents on In vitro Methane Production.

    PubMed

    Vázquez, Ernestina Gutiérrez; Medina, Leonardo Hernández; Benavides, Liliana Márquez; Caratachea, Aureliano Juárez; Razo, Guillermo Salas; Burgos, Armin Javier Ayala; Rodríguez, Ruy Ortiz

    2016-01-01

    The objective was to evaluate the effect of fodder tree species (FTS) with condensed tannin contents: Cordia elaeagnoides, Platymiscium lasiocarpum, Vitex mollis, and Haematoxylon brasiletto, on in vitro methane (CH4) production at 24 h post incubation. The analysis was performed using the in vitro gas production technique, with three levels of inclusion/species: 600, 800, and 1,000 mg and with 4 replicates/species/level of inclusion. The substrate was incubated at 39°C, and the gas and CH4 production were recorded at 4, 8, 12, and 24 h post incubation. The data collected was analyzed through Pearson correlation, polinomial regression and fixed effects models. There were negative correlations between FTS-total gas volume (r = -0.40; p<0.001); FTS-volume of CH4 produced (r = -0.40; p<0.001) and between the inclusion level-volume of CH4 produced (r = -0.20; p<0.001). As well as a positive correlation between hours post incubation-total gas volume (r = 0.42; p<0.001) and between hours post incubation-volume of CH4 produced (r = 0.48; p<0.001). The FTS: C. elaeagnoides, V. mollis, and H. brasiletto have potential, in the three inclusion levels analyzed, to reduce CH4 emission on in vitro trials (>32.7%), taking into account the total CH4 production at 24 h of the forage used as reference (Avena sativa). It's suggested that C. elaeagnoides-according to its crude protein, neutral detergent fiber, and condensed tannins content- is the best alternative within the FTS analyzed, for feeding ruminants and for the control of CH4 emissions during the dry season. PMID:26732330

  14. A new fatty aldol ester from the aerial part of Mimosa invisa (Mimosaceae).

    PubMed

    Nana, Frederic; Sandjo, Louis Pergaud; Keumedjio, Felix; Kuete, Victor; Ngadjui, Bonaventure Tchaleu

    2012-01-01

    A new aldol ester named 17-O-triacontanoylheptadecanal (1) was isolated from the aerial part of Mimosa invisa (Mimosaceae) together with eight known compounds identified as β-sitosterol (2), α-amyrine (3), lupeol (4), 4'-O-methylepinumisoflavone (5), alpinumisoflavone (6), betulinic acid (7), 3-O-β-D-glucopyranoside of sitosterol (8) and epirobinetinidol (9). The structures of compounds were determined on the basis of NMR and mass spectrometry data as well as by comparing the data reported in the literatures. The antimicrobial activities of the crude extract and compounds 1 and 9 were investigated against seven microbial species. The natural products showed moderate activities compared to that of the crude extract.

  15. Noninvasive multiphoton fluorescence microscopy resolves retinol and retinal condensation products in mouse eyes.

    PubMed

    Palczewska, Grazyna; Maeda, Tadao; Imanishi, Yoshikazu; Sun, Wenyu; Chen, Yu; Williams, David R; Piston, David W; Maeda, Akiko; Palczewski, Krzysztof

    2010-12-01

    Multiphoton excitation fluorescence microscopy (MPM) can image certain molecular processes in vivo. In the eye, fluorescent retinyl esters in subcellular structures called retinosomes mediate regeneration of the visual chromophore, 11-cis-retinal, by the visual cycle. But harmful fluorescent condensation products of retinoids also occur in the retina. We report that in wild-type mice, excitation with a wavelength of ∼730 nm identified retinosomes in the retinal pigment epithelium, and excitation with a wavelength of ∼910 nm revealed at least one additional retinal fluorophore. The latter fluorescence was absent in eyes of genetically modified mice lacking a functional visual cycle, but accentuated in eyes of older wild-type mice and mice with defective clearance of all-trans-retinal, an intermediate in the visual cycle. MPM, a noninvasive imaging modality that facilitates concurrent monitoring of retinosomes along with potentially harmful products in aging eyes, has the potential to detect early molecular changes due to age-related macular degeneration and other defects in retinoid metabolism.

  16. Method of carbon chain extension using novel aldol reaction

    DOEpatents

    Silks, Louis A; Gordon, John C; Wu, Ruilan; Hanson, Susan Kloek

    2013-07-30

    Method of producing C.sub.8-C.sub.15 hydrocarbons. comprising providing a ketone starting material; providing an aldol starting material comprising chloromethylfurfural; mixing the ketone starting material and the aldol starting material in a reaction in the presence of a proline-containing catalyst selected from the group consisting of Zn(Pro).sub.2, Yb(Pro).sub.3, and combinations thereof, or a catalyst having one of the structures (I), (II) or (III), and in the presence of a solvent, wherein the solvent comprises water and is substantially free of organic solvents, where (I), (II) and (III) respectively are: ##STR00001## where R.sub.1 is a C.sub.1-C.sub.6 alkyl moiety, X=(OH) and n=2. ##STR00002## In (III), X may be CH.sub.2, sulfur or selenium, M may be Zn, Mg, or a lanthanide, and R.sub.1 and R.sub.2 each independently may be a methyl, ethyl, phenyl moiety.

  17. Method of carbon chain extension using novel aldol reaction

    DOEpatents

    Silks, Louis A; Gordon, John C; Wu, Ruilan; Hangson, Susan Kloek

    2013-08-13

    Method of producing C.sub.8-C.sub.15 hydrocarbons comprising providing a ketone starting material; providing an aldol starting material comprising hydroxymethylfurfural; mixing the ketone starting material and the aldol starting material in a reaction in the presence of a proline-containing catalyst selected from the group consisting of Zn(Pro).sub.2, Yb(Pro).sub.2, and combinations thereof, or a catalyst having one of the structures (I), (II) or (III), and in the presence of a solvent, wherein the solvent comprises water and is substantially free of organic solvents, where (I), (II) and (III) respectively are: ##STR00001## where R.sub.1 is a C.sub.1-C.sub.6 alkyl moiety, X=(OH) and n=2. ##STR00002## In (III), X may be CH.sub.2, sulfur or selenium, M may be Zn, Mg, or a lanthanide, and R.sub.1 and R.sub.2 each independently may be a methyl, ethyl, phenyl moiety.

  18. Effects of condensation products of biogenic amines on human platelet function

    SciTech Connect

    Given, M.B.

    1983-01-01

    Condensation products (CP) are formed by the reaction of biogenic amines with aldehydes and alpha-keto acids. The purpose of this investigation was to examine the effects of CP on platelet function in vitro. The effect of CP on platelet aggregation was examined. Epinephrine-induced aggregation was inhibited, suggesting CP antagonistic activity on the platelet alpha/sub 2/-adrenergic receptors. Adenosine-diphosphate (ADP), collagen and arachidonic acid induced aggregation was inhibited only at high concentrations. Inhibition of epinephrine and ADP aggregation was reversible, suggesting CP are competitive inhibitors of these agonists. Binding affinities for the platelet alpha/sub 2/-adrenergic receptor were determined using (/sup 3/H)-yohimbine, a specific alpha/sup 2/-receptor antagonist. The order of potency for CP inhibition of (/sup 3/H)-yohimbine binding paralleled that determined for inhibition of epinephrine-induced aggregation. Platelet uptake of serotonin (5-HT) was competitively inhibited by CP, with the exception of salsolinol, which appears to be stimulatory. Release of 5-HT from platelets was induced by CP, with betacarbolines being more potent than tetrahydroisoquinolines. Evidence suggests that CP cause release by displacement of 5-HT from intraplatelet storage sites since this effect can be inhibited by imipramine, thus preventing accumulation of CP by platelets.

  19. l-Isoleucine in a Choline Chloride/Ethylene Glycol Deep Eutectic Solvent: A Reusable Reaction Kit for the Asymmetric Cross-Aldol Carboligation.

    PubMed

    Fanjul-Mosteirín, Noé; Concellón, Carmen; Del Amo, Vicente

    2016-09-01

    l-Isoleucine is able to catalyze the cross-aldol reaction between cyclohexanone and aromatic aldehydes in a deep eutectic solvent consisting in choline chloride and ethylene glycol, rendering products with high diatereo- and enantioselectivity. This protocol is straightforward and green: the organocatalyst and the reaction medium can be recycled up to five times, allowing the preparation of different substrates with a single load of solvent and catalyst.

  20. l-Isoleucine in a Choline Chloride/Ethylene Glycol Deep Eutectic Solvent: A Reusable Reaction Kit for the Asymmetric Cross-Aldol Carboligation.

    PubMed

    Fanjul-Mosteirín, Noé; Concellón, Carmen; Del Amo, Vicente

    2016-09-01

    l-Isoleucine is able to catalyze the cross-aldol reaction between cyclohexanone and aromatic aldehydes in a deep eutectic solvent consisting in choline chloride and ethylene glycol, rendering products with high diatereo- and enantioselectivity. This protocol is straightforward and green: the organocatalyst and the reaction medium can be recycled up to five times, allowing the preparation of different substrates with a single load of solvent and catalyst. PMID:27526718

  1. [The thermophilic streptomycetes flora in milk powders and condensed milk products (author's transl)].

    PubMed

    Falkowski, J

    1978-08-01

    247 specimens of powdered milk and 165 of condensed milk were tested for their contamination with thermophile Streptomycetes. Colonies of these contaminants were isolated from all specimens of powdered milk and from 73 samples of condensed sweeted milk. The isolated strains corresponded with the following species of thermophilic Streptomycetes: Thermoactinomyces vulgaris, Tsiklinsky 1899, Thermoactinomyces vulgaris, Tsiklinsky 1899 "giant colonies", Micromonospora sp. (Agre et al., 1).

  2. Origins of the double asymmetric induction on proline-catalyzed aldol reactions.

    PubMed

    Calderón, Félix; Doyagüez, Elisa G; Cheong, Paul Ha-Yeon; Fernández-Mayoralas, Alfonso; Houk, K N

    2008-10-17

    Computational studies to elucidate the origin of the double asymmetric induction on proline-catalyzed aldol reaction have been performed using HF/6-31G(d) calculations. The computed transition structures explain the experimental data obtained. PMID:18811197

  3. Diastereo- and Enantioselective Reductive Aldol Addition of Vinyl Ketones via Catalytic Hydrogenation

    PubMed Central

    Han, Soo Bong; Hassan, Abbas; Krische, Michael J.

    2011-01-01

    An overview of studies on hydrogenative reductive aldol addition is presented. By simply hydrogenating enones in the presence of aldehydes at ambient temperature and pressure, aldol adducts are generated under neutral conditions in the absence of any stoichiometric byproducts. Using cationic rhodium complexes modified by tri(2-furyl)phosphine, highly syn-diastereoselective reductive aldol additions of vinyl ketones are achieved. Finally, using novel monodentate TADDOL-like phosphonite ligands, the first highly diastereo- and enantioselective reductive aldol couplings of vinyl ketones were devised. These studies, along with other works from our laboratory, demonstrate that organometallics arising transiently in the course of catalytic hydrogenation offer byproduct-free alternatives to preformed organometallic reagents employed in classical carbonyl addition processes. PMID:21866204

  4. Fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap

    SciTech Connect

    Heo, Myoung-Sun; Choi, Jae-yoon; Shin, Yong-il

    2011-01-15

    We demonstrate a fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap. A single global minimum of the trapping potential is generated by slightly displacing the plug beam from the center of the quadrupole field. With a dark magneto-optical trap and a simple rf evaporation, our system produces a condensate with N{approx_equal}10{sup 7} atoms every 17 s. The Majorana loss rates and the resultant heating rates for various temperatures are measured with and without plugging. The average energy of a spin-flipped atom is almost linearly proportional to temperature and determined to be about 60% of the average energy of a trapped atom. We present a numerical study of the evaporation dynamics in a plugged linear trap.

  5. The role of free radical condensates in the production of carbon nanotubes during the hydrocarbon CVD process

    SciTech Connect

    Reilly, Pete; Whitten, William B

    2006-06-01

    Hydrocarbon CVD synthesis of carbon nanotubes (CNTs) is not well understood because it does not follow intuitive gas phase kinetics. Consequently, progress towards industrialization of CNT synthesis has been arduously slow. However, an intuitive understanding of the CNT CVD process can be gained through understanding of the chemistry of free radical condensates that are produced during the pyrolysis of any hydrocarbon. It is our contention that free radical condensates act as an intermediate and reaction medium for hydrocarbon-based CVD production of nanotubes. The insight gained from this understanding can be used to explain much of the literature and to coherently direct the efforts to industrialize the CVD process and produce higher quality nanotubes for materials research and commercial exploitation.

  6. Production of large 41K Bose-Einstein condensates using D1 gray molasses

    NASA Astrophysics Data System (ADS)

    Chen, Hao-Ze; Yao, Xing-Can; Wu, Yu-Ping; Liu, Xiang-Pei; Wang, Xiao-Qiong; Wang, Yu-Xuan; Chen, Yu-Ao; Pan, Jian-Wei

    2016-09-01

    We use D1 gray molasses to achieve Bose-Einstein condensation of a large number of 41K atoms in an optical dipole trap. By combining a specific configuration of a compressed magneto-optical trap with D1 gray molasses, we obtain a cold sample of 2.4 ×109 atoms with a temperature as low as 42 μ K . After magnetically transferring the atoms into the final glass cell, we perform a two-stage evaporative cooling. A condensate with up to 1.2 ×106 atoms in the lowest Zeeman state |F =1 , mF=1 > is achieved in the optical dipole trap. Furthermore, we observe two narrow Feshbach resonances in the lowest hyperfine channel, which are in good agreement with theoretical predictions.

  7. Distortion of interference fringes and the resulting vortex production of merging Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Xiong, Bo; Yang, Tao; Benedict, Keith A.

    2013-10-01

    We investigate the effects of interatomic interactions and expansion on the distortion of interference fringes of a pair of initially well-separated, but coherent, condensate clouds trapped in a harmonic trap. The distortion of interference fringes, which can lead to the spontaneous formation of vortices in the atom clouds, depends crucially on two relevant parameters: the center-of-mass velocity and peak density of the initial state. We identify three qualitatively distinct regimes for the interfering condensates: collision, expansion, and merging, by the spatial and temporal features of the fringe spacings. Using a comprehensive set of numerical simulations based on the Gross-Pitaevskii equation, we specify the crossovers between these regimes and propose the optimal system parameters required for dynamical instabilities and vortex creation.

  8. CYCLODEXTRIN-BASED CLASS I ALDOLASE ENZYME MIMICS TO CATALYZE CROSSED ALDOL CONDENSATIONS. (R826653)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  9. Production and condensation of organic gases in the atmosphere of Titan

    NASA Astrophysics Data System (ADS)

    Sagan, C.; Thompson, W. R.

    1984-08-01

    The rates and altitudes for the dissociation of atmospheric constituents on Titan are calculated for solar ultraviolet radiation, the solar wind, Saturn magnetospheric particles, the Saturn co-rotating plasma, and cosmic rays. Laboratory experiments show that a variety of simple gas phase organic molecules and more complex organic solids called tholins are produced by such irradiations of simulated Titanian atmospheres. Except for ultraviolet wavelengths longward of the methane photodissociation continuum, most dissociation events occur between about 3100 and 3600 km altitude, corresponding well to the region of EUV opacity detected by Voyager. For a wide variety of simple to moderately complex organic gases in the Titanian atmosphere, condensation occurs below the top of the main cloud deck at about 2825 km. It is proposed that such condensates, begining with CH4 at about 2615 km comprise the principal mass of the Titan clouds. There is a distinct tendency for the atmosphere of Titan to act as a fractional distillation device, molecules of greater complexity condensing out at higher altitudes.

  10. Production and condensation of organic gases in the atmosphere of Titan

    NASA Technical Reports Server (NTRS)

    Sagan, C.; Thompson, W. R.

    1982-01-01

    The rates and altitudes for the dissociation of atmospheric constituents on Titan are calculated for solar ultraviolet radiation, the solar wind, Saturn magnetospheric particles, the Saturn co-rotating plasma, and cosmic rays. Laboratory experiments show that a variety of simple gas phase organic molecules and more complex organic solids called tholins are produced by such irradiations of simulated Titanian atmospheres. Except for ultraviolet wavelengths longward of the methane photodissociation continuum, most dissociation events occur between about 3100 and 3600 km altitude, corresponding well to the region of EUV opacity detected by Voyager. For a wide variety of simple to moderately complex organic gases in the Titanian atmosphere, condensation occurs below the top of the main cloud deck at about 2825 km. It is proposed that such condensates, beginning with CH4 at about 2615 km, comprise the principal mass of the Titan clouds. There is a distinct tendency for the atmosphere of Titan to act as a fractional distillation device, molecules of greater complexity condensing out at higher altitudes.

  11. Evidence for the formation of an enamine species during aldol and Michael-type addition reactions promiscuously catalyzed by 4-oxalocrotonate tautomerase.

    PubMed

    Poddar, Harshwardhan; Rahimi, Mehran; Geertsema, Edzard M; Thunnissen, Andy-Mark W H; Poelarends, Gerrit J

    2015-03-23

    The enzyme 4-oxalocrotonate tautomerase (4-OT), which has a catalytic N-terminal proline residue (Pro1), can promiscuously catalyze various carbon-carbon bond-forming reactions, including aldol condensation of acetaldehyde with benzaldehyde to yield cinnamaldehyde, and Michael-type addition of acetaldehyde to a wide variety of nitroalkenes to yield valuable γ-nitroaldehydes. To gain insight into how 4-OT catalyzes these unnatural reactions, we carried out exchange studies in D2 O, and X-ray crystallography studies. The former established that H-D exchange within acetaldehyde is catalyzed by 4-OT and that the Pro1 residue is crucial for this activity. The latter showed that Pro1 of 4-OT had reacted with acetaldehyde to give an enamine species. These results provide evidence of the mechanism of the 4-OT-catalyzed aldol and Michael-type addition reactions in which acetaldehyde is activated for nucleophilic addition by Pro1-dependent formation of an enamine intermediate.

  12. Utilization of Condensed Distillers Solubles as Nutrient Supplement for Production of Nisin and Lactic Acid from Whey

    NASA Astrophysics Data System (ADS)

    Liu, Chuanbin; Hu, Bo; Chen, Shulin; Glass, Richard W.

    The major challenge associated with the rapid growth of the ethanol industry is the usage of the coproducts, i.e., condensed distillers solubles (CDS) and distillers dried grains, which are currently sold as animal feed supplements. As the growth of the livestock industries remains flat, alternative usage of these coproducts is urgently needed. CDS is obtained after the removal of ethanol by distillation from the yeast fermentation of a grain or a grain mixture by condensing the thin stillage fraction to semisolid. In this work, CDS was first characterized and yeast biomass was proven to be the major component of CDS. CDS contained 7.50% crude protein but with only 42% of that protein being water soluble. Then, CDS was applied as a nutrient supplement for simultaneous production of nisin and lactic acid by Lactococcus lactis subsp. lactis (ATCC 11454). Although CDS was able to support bacteria growth and nisin production, a strong inhibition was observed when CDS was overdosed. This may be caused by the existence of the major ethanol fermentation byproducts, especially lactate and acetate, in CDS. In the final step, the CDS based medium composition for nisin and lactic acid production was optimized using response surface methodology.

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

    PubMed

    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.

  14. Interaction of yeasts with the products resulting from the condensation reaction between (+)-catechin and acetaldehyde.

    PubMed

    Lopez-Toledano, Azahara; Villaño-Valencia, Debora; Mayen, Manuel; Merida, Julieta; Medina, Manuel

    2004-04-21

    The condensation reaction between (+)-catechin and acetaldehyde was studied in model solutions in the presence and absence yeasts in order to evaluate its contribution to color changes in fermented drinks such as white wine. On the basis of the results, the yeasts retain the oligomers produced in the reaction, their retention ability increasing for higher polymerization degrees. As a result, the color of model solutions, measured as the absorbance at 420 nm, was found to decrease after the addition of yeasts. On the other hand, the yeasts exhibited no inhibitory effect on the condensation reaction, which took place at the same rate in their presence and absence. At acidity levels and reactant concentrations similar to those in wine, with acetaldehyde in high concentration as it is present in sherry wines, the reaction was found to occur very slowly. Taking into account that Yeasts are present during most of the winemaking process; consequently, they retain oligomers, and the studied reaction could mainly contribute to the alteration of the color of white wine after bottling. PMID:15080649

  15. A Compact, Transportable, Microchip-Based System for High Repetition Rate Production of Bose-Einstein Condensates

    NASA Astrophysics Data System (ADS)

    Farkas, Daniel; Hudek, Kai; Salim, Evan; Segal, Stephen; Anderson, Dana

    2010-03-01

    We present a compact, transportable system that produces Bose-Einstein condensates (BECs) near the surface of an integrated atom microchip. Occupying a volume of 0.4 m^3 and consuming an average power of 525 W, the system contains all of the components needed to produce and image BECs, including an ultra-high vacuum system, lasers, data acquisition hardware, electronics, and imaging equipment. RF evaporative cooling forms nearly-pure condensates containing 1.9x10^4 ^87Rb atoms in the |F=2,mF=+2> ground hyperfine state. With trap frequencies of several kHz, evaporative cooling times as short as 1.5 s have been used to create BECs, resulting in production repetition rates as high as 0.3 Hz. The system can be easily reconfigured for use with atom chips having wire patterns designed for different applications. As such, it can serve as a standardized platform for a variety of portable experiments that utilize ultracold matter.

  16. Crystal Structures of Quinolinate Synthase in Complex with a Substrate Analogue, the Condensation Intermediate, and Substrate-Derived Product.

    PubMed

    Volbeda, Anne; Darnault, Claudine; Renoux, Oriane; Reichmann, Debora; Amara, Patricia; Ollagnier de Choudens, Sandrine; Fontecilla-Camps, Juan C

    2016-09-14

    The enzyme NadA catalyzes the synthesis of quinolinic acid (QA), the precursor of the universal nicotinamide adenine dinucleotide (NAD) cofactor. Here, we report the crystal structures of complexes between the Thermotoga maritima (Tm) NadA K219R/Y107F variant and (i) the first intermediate (W) resulting from the condensation of dihydroxyacetone phosphate (DHAP) with iminoaspartate and (ii) the DHAP analogue and triose-phosphate isomerase inhibitor phosphoglycolohydroxamate (PGH). In addition, using the TmNadA K219R/Y21F variant, we have reacted substrates and obtained a crystalline complex between this protein and the QA product. We also show that citrate can bind to both TmNadA K219R and its Y21F variant. The W structure indicates that condensation causes dephosphorylation. We propose that catalysis by the K219R/Y107F variant is arrested at the W intermediate because the mutated protein is unable to catalyze its aldo-keto isomerization and/or cyclization that ultimately lead to QA formation. Intriguingly, PGH binds to NadA with its phosphate group at the site where the carboxylate groups of W also bind. Our results shed significant light on the mechanism of the reaction catalyzed by NadA. PMID:27545412

  17. A self-assembled nanotube for the direct aldol reaction in water.

    PubMed

    Lee, Kwang Soo; Parquette, Jon R

    2015-11-01

    Nanotubes formed by the aqueous assembly of a proline-lysine dipeptide (1) were used to create the hydrophobic microenvironments required to catalyze the aldol reaction in water. The self-assembly process occurred most efficiently in the presence of the substrates, producing an array of homogeneous nanotubes under the reaction conditions. The nanotubes formed by dipeptide 1 served as an efficient catalyst for the aldol reaction that functioned at low loading levels and provided good to excellent conversions. The catalytic activity of 1 was minimal under conditions that dissociated the nanotube into soluble monomers.

  18. Dynamic Kinetic Asymmetric Transformations of β-Stereogenic-α-Keto Esters via Direct Aldolization

    PubMed Central

    Corbett, Michael T.; Johnson, Jeffrey S.

    2014-01-01

    Dynamic kinetic asymmetric transformations (DyKAT) of racemic β-bromo-α-keto esters via direct aldolization of nitromethane and acetone provide access to fully substituted α-glycolic acid derivatives bearing a β-stereocenter. The aldol adducts are obtained in excellent yield with high relative and absolute stereocontrol under mild reaction conditions. Mechanistic studies determined that the reactions proceed through a facile catalyst-mediated racemization of the β-bromo-α-keto esters under a DyKAT Type I manifold. PMID:24222195

  19. Highly active copper-network catalyst for the direct aldol reaction.

    PubMed

    Ohta, Hidetoshi; Uozumi, Yasuhiro; Yamada, Yoichi M A

    2011-09-01

    The development of a highly active solid-phase catechol-copper network catalyst for direct aldol reaction is described. The catalyst was prepared from an alkyl-chain-linked bis(catechol) and a copper(II) complex. The direct aldol reaction between carbonyl compounds (aldehydes and ketones) and methyl isocyanoacetate was carried out using 0.1-1 mol% [Cu] catalyst to give the corresponding oxazolines at yields of up to 99% and a trans/cis ratio of >99:1. The catalyst was reused with no loss of catalytic activity. A plausible reaction pathway is also described. PMID:21751405

  20. Delayed production of sulfuric acid condensation nuclei in the polar stratosphere from El Chichon volcanic vapors

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Rosen, J. M.; Gringel, W.

    1985-01-01

    It is pointed out that measurements of the vertical profiles of atmospheric condensation nuclei (CN) have been conducted since 1973. Studies with a new instrument revealed that the CN concentration undergoes a remarkable annual variation in the 30-km region characterized by a large increase in the late winter/early spring period with a subsequent decay during the remainder of the year. The event particles are observed to be volatile at 150 C, suggesting a sulfuric acid-water composition similar to that found in the normal 20 km aerosol layer. The development of about 10 to the 7th metric tons of sulfuric acid aerosol following the injection of sulfurous gases by El Chichon in April 1982, prompted Hofmann and Rosen (1983) to predict a very large CN event for 1983. The present investigation is concerned with the actual observation of the predicted event. Attention is given to the observation of a very large increase of what appear to be small sulfuric acid droplets at 30-km altitude in January 1983 over Laramie, WY, in January 1983.

  1. Total Synthesis of the Antimicrotubule Agent (+)-Discodermolide Using Boron-Mediated Aldol Reactions of Chiral Ketones.

    PubMed

    Paterson; Florence; Gerlach; Scott

    2000-01-01

    With a similar mechanism of action to taxol, the title compound 1 is a particularly promising candidate for development in cancer chemotherapy. This efficient synthesis, based on stereocontrolled aldol reactions, should help to overcome the scarce natural supply of 1 from the rare sponge source.

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

    EPA Science Inventory


    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...

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

    EPA Science Inventory

    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...

  4. Asymmetric total synthesis of smyrindiol employing an organocatalytic aldol key step

    PubMed Central

    Fronert, Jeanne; Bisschops, Tom; Boeck, Florian

    2012-01-01

    Summary The first organocatalytic asymmetric synthesis of smyrindiol, by using an (S)-proline catalyzed enantioselective intramolecular aldol reaction as the key step, is described. Smyrindiol was synthesized from commercially available 2,4-dihydroxybenzaldehyde in 15 steps, with excellent stereoselectivity (de = 99%, ee = 99%). In the course of this total synthesis a new and mild coumarin assembly was developed. PMID:23019438

  5. Diffractive dijet production in deep inelastic scattering and photon-hadron collisions in the color glass condensate

    NASA Astrophysics Data System (ADS)

    Altinoluk, Tolga; Armesto, Néstor; Beuf, Guillaume; Rezaeian, Amir H.

    2016-07-01

    We study exclusive dijet production in coherent diffractive processes in deep inelastic scattering and real (and virtual) photon-hadron (γ (*)-h) collisions in the Color Glass Condensate formalism at leading order. We show that the diffractive dijet cross section is sensitive to the color-dipole orientation in the transverse plane, and is a good probe of possible correlations between the q q bar -dipole transverse separation vector r and the dipole impact parameter b. We also investigate the diffractive dijet azimuthal angle correlations and t-distributions in γ (*)-h collisions and show that they are sensitive to gluon saturation effects in the small-x region. In particular, we show that the t-distribution of diffractive dijet photo-production off a proton target exhibits a dip-type structure in the saturation region. This effect is similar to diffractive vector meson production. Besides, at variance with the inclusive case, the effect of saturation leads to stronger azimuthal correlations between the jets.

  6. CONDENSATION CAN

    DOEpatents

    Booth, E.T. Jr.; Pontius, R.B.; Jacobsohn, B.A.; Slade, C.B.

    1962-03-01

    An apparatus is designed for condensing a vapor to a solid at relatively low back pressures. The apparatus comprises a closed condensing chamber, a vapor inlet tube extending to the central region of the chamber, a co-axial tubular shield surrounding the inlet tube, means for heating the inlet tube at a point outside the condensing chamber, and means for refrigeratirg the said chamber. (AEC)

  7. Influence of Condensed Tannins from Ficus bengalensis Leaves on Feed Utilization, Milk Production and Antioxidant Status of Crossbred Cows

    PubMed Central

    Dey, Avijit; De, Partha Sarathi

    2014-01-01

    This study was conducted to examine the effects of condensed tannins (CT) from Ficus bengalensis leaves on the feed utilization, milk production and health status of crossbred cows. Eighteen crossbred dairy cows at their second and mid lactation (avg. BW 351.6±10.6 kg) were randomly divided into two groups of nine each in a completely randomized block design and fed two iso-nitrogenous supplements formulated to contain 0% and 1.5% CT through dried and ground leaves of Ficus bengalensis. The diets were designated as CON and FBLM, respectively and fed to cows with a basal diet of rice straw to meet requirements for maintenance and milk production. The daily milk yield was significantly (p<0.05) increased due to supplementation of FBLM diet. The 4% fat corrected milk yield was also significantly (p<0.01) higher due to increased (p<0.05) milk fat in cows under diet FBLM as compared to CON. The inclusion of CT at 1.5% in the supplement did not interfere with the feed intake or digestibility of DM, OM, CP, EE, NDF, and ADF by lactating cows. Digestible crude protein (DCP) and total digestible nutrients (TDN) values of the composite diets were comparable between the groups. The blood biochemical parameters remained unaltered except significantly (p<0.05) lowered serum urea concentration in cows fed FBLM diet. There was a significant (p<0.05) increase intracellular reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) activity in cows supplemented with condensed tannins. The total thiol group (T-SH) was found to be higher with reduction in lipid peroxidation (LPO) in cows of FBLM group. The cost of feeding per kg milk production was also reduced due to supplementation of Ficus bengalensis leaves. Therefore, a perceptible positive impact was evident on milk production and antioxidant status in crossbred cows during mid-lactation given supplement containing 1.5% CT through Ficus bengalensis leaves. PMID:25049960

  8. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2014-07-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1-2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  9. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2015-01-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1-2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes, especially those with relatively low carbon numbers (C4-15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  10. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGES

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2014-07-03

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1–2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products ofmore » both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  11. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGES

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2015-01-16

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1–2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction productsmore » of both aromatics and alkanes, especially those with relatively low carbon numbers (C4–15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  12. Nonequilibrium production of photons via {pi}{sup 0}{r_arrow}2{gamma} in disoriented chiral condensates

    SciTech Connect

    Boyanovsky, D.; de Vega, H.J.; Holman, R.; Prem Kumar, S.

    1997-10-01

    We study the production of photons via the nonequilibrium relaxation of a disoriented chiral condensate with the chiral order parameter having a large initial amplitude along the {pi}{sup 0} direction. Assuming the validity of the low-energy coupling of the neutral pion to photons via the U{sub A}(1) anomalous vertex, we find that for large initial amplitudes along the {pi}{sup 0} direction photon production is enhanced by parametric amplification. These processes are nonperturbative with a large contribution during the nonequilibrium stages of the evolution and result in a distinct distribution of the produced photons and a polarization asymmetry. For initial amplitudes of the {pi}{sup 0} component of the order parameter between 200 and 400 MeV, corresponding to energy densities between 1 and 12 GeV/fm{sup 3}, we find a peak in the photon distribution at energies between {approx}300 and 600 MeV. We also find polarization asymmetries typically between 5{percent} and 10{percent}. We discuss the potential experimental impact of these results as well as the problems associated with its detection. {copyright} {ital 1997} {ital The American Physical Society}

  13. Effects of brewers` condensed solubles (BCS) on the production of ethanol from low-grade starch materials

    SciTech Connect

    Choi, C.H.; Chung, D.S.; Seib, P.A.

    1995-02-01

    Yeast fermentation was performed on grain and bakery byproducts with and without adding the same volume of brewers` condensed solubles (BCS). Starch material in the grain and bakery byproducts effectively was converted to fermentable sugars with conversion ratios of 93-97% by successive treatments of samples with bacterial {alpha}-amylase and fungal glucoamylase. The yeast fermentation of these enzyme-digested byproducts alone showed that ethanol concentrations of 16.4-42.7 mL/100 g dry solid in the broth were achieved with fermentation efficiencies of 87-96%. Addition of BCS to the grain byproducts increased ethanol concentration by 10-86% by increasing the potential glucose content of the broth. The rates of fermentation measured by CO{sub 2} gas production demonstrated that BCS addition to bakery byproducts reduced the fermentation time from 62-72 h to 34-35 h. In bakery byproducts that were low in amino nitrogen, exhaustion of nitrogenous compounds in substrates was found to be a limiting factor for yeast growth. Because BCS is a rich source of nitrogen, adding BCS to these substrates markedly increased the fermentation rate. 15 refs., 4 figs., 3 tabs.

  14. Soliton and phonon production by an oscillating obstacle in a quasi-one-dimensional trapped repulsive Bose-Einstein condensate

    SciTech Connect

    Radouani, Abdelaziz

    2004-07-01

    We use the one-dimensional (1D) Gross-Pitaevskii equation to investigate the dynamical evolution of a dilute repulsive Bose-Einstein condensate (BEC) confined in an elongated static nonharmonic trap and stirred by an oscillating Gaussian obstacle moving at uniform speed in alternate direction. Direct numerical solutions of this equation show that above a critical obstacle velocity, the motion of the obstacle creates gray solitons and phonons. At first, when the velocity of the obstacle increases, the dissipation also increases. But the dissipation reaches a maximal value and then decreases dramatically and vanishes at high obstacle velocities. Our results at low obstacle velocities are similar to those previously obtained experimentally and by simulations in the case of vortice and phonon production in 3D and 2D trapped repulsive BEC's. But at high obstacle velocities, we show that the quasi-1D trapped repulsive BEC behaves as a quasisuperfluid medium with disappearance of gray soliton and phonon excitations. This extends previous results and provides the main dependence of the phenomenon on the obstacle characteristics.

  15. A compact, transportable, microchip-based system for high repetition rate production of Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Farkas, Daniel M.; Hudek, Kai M.; Salim, Evan A.; Segal, Stephen R.; Squires, Matthew B.; Anderson, Dana Z.

    2010-03-01

    We present a compact, transportable system that produces Bose-Einstein condensates near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m3, operates at a repetition rate as high as 0.3 Hz, and consumes an average power of 525 W. Evaporative cooling in a chip trap with trap frequencies of several kilohertz leads to nearly pure condensates containing 1.9×104 R87b atoms. Partial condensates are observed at a temperature of 1.58(8) μK, close to the theoretical transition temperature of 1.1 μK.

  16. Sedimentary condensation and authigenesis

    NASA Astrophysics Data System (ADS)

    Föllmi, Karl

    2016-04-01

    Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin (< 1m) beds, which were accumulated during extremely long time periods (> 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and

  17. Parameterization of the ReaxFF reactive force field for a proline-catalyzed aldol reaction.

    PubMed

    Hubin, Pierre O; Jacquemin, Denis; Leherte, Laurence; Vercauteren, Daniel P

    2016-11-01

    A parameterization of the ReaxFF reactive FF is performed using a Monte Carlo Simulated Annealing procedure for the modeling of a proline-catalyzed aldol reaction. Emphasis is put on the accurate reproduction of the relative stabilities of several key intermediates of the reaction, as well as, on the description of the reaction path bridging these intermediates based on quantum mechanical calculations. Our training sets include new criteria based on geometry optimizations and short Molecular Dynamics simulations to ensure that the trained ReaxFF potentials adequately predict the structures of all key intermediates. The transferability of the sets of parameters obtained is assessed for various steps of the considered aldol reaction, as well as for different substrates, catalysts, and reagents. This works indeed highlights the challenge of reaching transferable parameters for several reaction steps. © 2016 Wiley Periodicals, Inc.

  18. Enantioselective aldol reaction between isatins and cyclohexanone catalyzed by amino acid sulphonamides.

    PubMed

    Wang, Jun; Liu, Qi; Hao, Qing; Sun, Yanhua; Luo, Yiming; Yang, Hua

    2015-04-01

    Sulphonamides derived from primary α-amino acid were successfully applied to catalyze the aldol reaction between isatin and cyclohexanone under neat conditions. More interestingly, molecular sieves, as privileged additives, were found to play a vital role in achieving high enantioselectivity. Consequently, high yields (up to 99%) along with good enantioselectivities (up to 92% ee) and diastereoselectivities (up to 95:5 dr) were obtained. In addition, this reaction was also conveniently scaled up, demonstrating the applicability of this protocol.

  19. Organocatalytic enantioselective tandem aldol-cyclization reaction of α-isothiocyanato imides and activated carbonyl compounds

    PubMed Central

    Guang, Jie; Zhao, Cong-Gui

    2011-01-01

    The organocatalytic enantioselective tandem aldol-cyclization reactions of α-isothiocyanato imides and activated carbonyl compounds, such as isatins, an α-ketolactone and a 1,2-dione, have been studied with cinchona alkaloid-derived thiourea-catalysts. This methodology provided an easy way to access enantiomerically enriched spirobicyclic thiocarbamates with high yields and good to excellent stereoselectivity, which have been demonstrated to be useful precursors for the synthesis of biologically active molecules. PMID:21921975

  20. Development of chiral catalysts for Mukaiyama aldol reactions in aqueous media.

    PubMed

    Kitanosono, Taku; Kobayashi, Shū

    2014-02-01

    Since the discovery of the Mukaiyama aldol reaction in 1973, tremendous efforts have been made to develop a definitive catalyst that catalyzes asymmetric Mukaiyama aldol reactions under mild conditions with broad substrate tolerance. Forty years later, an exhaustive search for a water-compatible Lewis acid was able to uncover the hidden potential of iron(II) and bismuth(III), leading to the establishment of broadly applicable and versatile catalytic systems for asymmetric Mukaiyama aldol reactions in aqueous media. The ternary catalytic system was able to expand the substrate generality considerably as the most distinguished catalyst ever reported. The superiority of this methodology over conventional methods has also been demonstrated in terms of high catalytic activity, simplicity of experimental procedures, and a wide substrate range including aqueous aldehydes, for which the stereochemistry had been regarded as difficult to control. Furthermore, a facile synthesis of the chiral ligand underscores its versatility. The reaction did not proceed at all without use of water. In the postulated mechanism, water plays prominent roles in: (1) producing the active metal complexes with a high water-exchange rate constant (3.2 × 10(6)) to activate substrates effectively and to catalyze the reaction through a rapid proton transfer on the order of picoseconds; (2) facilitating the catalytic turnover with simultaneous desilylation as direct access to aldol adducts or facile recovery of active metal complexes; and (3) stabilizing rigid transition states composed of metal complexes and reactants through entropy-driven aggregation derived from the highest cohesive energy density. PMID:24449534

  1. One-Pot Domino Aldol Reaction of Indium Enolates Affording 6-Deoxy-α-D,L-altropyranose Derivatives: Synthesis, Mechanism, and Computational Results.

    PubMed

    Cinar, M Emin; Schmittel, Michael

    2015-08-21

    The domino-aldol-aldol-hemiacetal-reaction cascade of indium and other group 13 metal enolates furnished 6-deoxy-α-D,L-altropyranose derivatives in up to 99% yield under thermodynamic control. At lower temperature and thus under kinetic control, the reaction proceeded in a much less diastereoselective manner. The changeover from kinetic to thermodynamic control operating in this multistep domino-aldol-aldol-hemiacetal protocol was used for probing the efficiency of DFT computations. Calculations at the B3LYP/6-31G(d)/LANL2DZ level provided a mechanistic picture in full agreement with the experimental outcome. PMID:26258596

  2. One-Pot Domino Aldol Reaction of Indium Enolates Affording 6-Deoxy-α-D,L-altropyranose Derivatives: Synthesis, Mechanism, and Computational Results.

    PubMed

    Cinar, M Emin; Schmittel, Michael

    2015-08-21

    The domino-aldol-aldol-hemiacetal-reaction cascade of indium and other group 13 metal enolates furnished 6-deoxy-α-D,L-altropyranose derivatives in up to 99% yield under thermodynamic control. At lower temperature and thus under kinetic control, the reaction proceeded in a much less diastereoselective manner. The changeover from kinetic to thermodynamic control operating in this multistep domino-aldol-aldol-hemiacetal protocol was used for probing the efficiency of DFT computations. Calculations at the B3LYP/6-31G(d)/LANL2DZ level provided a mechanistic picture in full agreement with the experimental outcome.

  3. A practical synthesis of (+)-discodermolide and analogues: fragment union by complex aldol reactions.

    PubMed

    Paterson, I; Florence, G J; Gerlach, K; Scott, J P; Sereinig, N

    2001-10-01

    A practical stereocontrolled synthesis of (+)-discodermolide (1) has been completed in 10.3% overall yield (23 steps longest linear sequence). The absolute stereochemistry of the C(1)-C(6) (7), C(9)-C(16) (8), and C(17)-C(24) (9) subunits was established via substrate-controlled, boron-mediated, aldol reactions of the chiral ethyl ketones 10, 11, and 12. Key fragment coupling reactions were a lithium-mediated, anti-selective, aldol reaction of aryl ester 8 (under Felkin-Anh induction from the aldehyde component 9), followed by in situ reduction to produce the 1,3-diol 40, and a (+)-diisopinocampheylboron chloride-mediated aldol reaction of methyl ketone 7 (overturning the inherent substrate induction from the aldehyde component 52) to give the (7S)-adduct 58. The flexibility of our overall strategy is illustrated by the synthesis of a number of diastereomers and structural analogues of discodermolide, which should serve as valuable probes for structure-activity studies.

  4. Condensation polyimides

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1989-01-01

    Polyimides belong to a class of polymers known as polyheterocyclics. Unlike most other high temperature polymers, polyimides can be prepared from a variety of inexpensive monomers by several synthetic routes. The glass transition and crystalline melt temperature, thermooxidative stability, toughness, dielectric constant, coefficient of thermal expansion, chemical stability, mechanical performance, etc. of polyimides can be controlled within certain boundaries. This versatility has permitted the development of various forms of polyimides. These include adhesives, composite matrices, coatings, films, moldings, fibers, foams and membranes. Polyimides are synthesized through both condensation (step-polymerization) and addition (chain growth polymerization) routes. The precursor materials used in addition polyimides or imide oligomers are prepared by condensation method. High molecular weight polyimide made via polycondensation or step-growth polymerization is studied. The various synthetic routes to condensation polyimides, structure/property relationships of condensation polyimides and composite properties of condensation polyimides are all studied. The focus is on the synthesis and chemical structure/property relationships of polyimides with particular emphasis on materials for composite application.

  5. Anesthetic effects changeable in habitual drinkers: Mechanistic drug interactions with neuro-active indoleamine-aldehyde condensation products associated with alcoholic beverage consumption.

    PubMed

    Tsuchiya, Hironori

    2016-07-01

    Clinicians often experience the reduced efficacy of general and local anesthetics and anesthesia-related drugs in habitual drinkers and chronic alcoholics. However, the mechanistic background underlying such anesthetic tolerance remains unclear. Biogenic indoleamines condense with alcohol-derived aldehydes during fermentation processes and under physiological conditions to produce neuro-active tetrahydro-β-carbolines and β-carbolines, many of which are contained not only in various alcoholic beverages but also in human tissues and body fluids. These indoleamine-aldehyde condensation products are increased in the human body because of their exogenous and endogenous supply enhanced by alcoholic beverage consumption. Since tetrahydro-β-carbolines and β-carbolines target receptors, ion channels and neuronal membranes which are common to anesthetic agents, we propose a hypothesis that they may pharmacodynamically interact at GABAA receptors, NMDA receptors, voltage-gated Na(+) channels and membrane lipid bilayers to attenuate anesthetics-induced positive allosteric GABAA receptor modulation, NMDA receptor antagonism, ion channel blockade and neuronal membrane modification, thereby affecting anesthetic efficacy. The condensation products may also cooperatively interact with ethanol that induces adaptive changes and cross-tolerance to anesthetics and with dopamine-aldehyde adducts that act on GABAA receptors and membrane lipids. Because tetrahydro-β-carbolines and β-carbolines are metabolized to lose or decrease their neuro-activities, induction of the relevant enzymes by habitual drinking could produce an inter-individual difference of drinkers in susceptibility to anesthetic agents. The present hypothesis would also provide a unified framework for different modes of anesthetic action, which are inhibited by neuro-active indoleamine-aldehyde condensation products associated with alcoholic beverage consumption. PMID:27241259

  6. Resole resin products derived from fractionated organic and aqueous condensates made by fast-pyrolysis of biomass materials

    DOEpatents

    Chum, H.L.; Black, S.K.; Diebold, J.P.; Kreibich, R.E.

    1993-08-10

    A process for preparing phenol-formaldehyde resole resins by fractionating organic and aqueous condensates made by fast-pyrolysis of biomass materials while using a carrier gas to move feed into a reactor to produce phenolic-containing/neutrals in which portions of the phenol normally contained in said resins are replaced by a phenolic/neutral fractions extract obtained by fractionation.

  7. Resole resin products derived from fractionated organic and aqueous condensates made by fast-pyrolysis of biomass materials

    DOEpatents

    Chum, Helena L.; Black, Stuart K.; Diebold, James P.; Kreibich, Roland E.

    1993-01-01

    A process for preparing phenol-formaldehyde resole resins by fractionating organic and aqueous condensates made by fast-pyrolysis of biomass materials while using a carrier gas to move feed into a reactor to produce phenolic-containing/neutrals in which portions of the phenol normally contained in said resins are replaced by a phenolic/neutral fractions extract obtained by fractionation.

  8. The structure investigations of dehydroacetic acid and 1,8-diaminonaphthalene condensation product by NMR, MS, and X-ray measurements

    NASA Astrophysics Data System (ADS)

    Kołodziej, B.; Morawiak, M.; Kamieński, B.; Schilf, W.

    2016-05-01

    A new unexpected product of condensation reaction of 1,8-diaminonaphthalene (DAN) and carbonyl compound (here: dehydroacetic acid (dha)) was synthesized. Discussion about the molecular structure of possible products of this reaction was done on the base of NMR studies. The structure of the titled product in both DMSO solution and in the solid state was resolved by analysis of its spectral data (X-ray structure analysis, multinuclear NMR in solution and solid state spectra) and MS measurements. The presented studies provided clear evidence that the titled product exists in diluted DMSO solution as the mixture of two kinetic free ionic species whereas in concentrated DMSO solution as well as in the solid state this system forms associated ionic pairs bonded together by hydrogen bonds.

  9. Polariton condensates

    SciTech Connect

    Snoke, David; Littlewood, Peter

    2010-08-15

    Most students of physics know about the special properties of Bose-Einstein condensates (BECs) as demonstrated in the two best-known examples: superfluid helium-4, first reported in 1938, and condensates of trapped atomic gases, first observed in 1995. (See the article by Wolfgang Ketterle in PHYSICS TODAY, December 1999, page 30.) Many also know that superfluid {sup 3}He and superconducting metals contain BECs of fermion pairs. An underlying principle of all those condensed-matter systems, known as quantum fluids, is that an even number of fermions with half-integer spin can be combined to make a composite boson with integer spin. Such composite bosons, like all bosons, have the property that below some critical temperature--roughly the temperature at which the thermal de Broglie wavelength becomes comparable to the distance between the bosons--the total free energy is minimized by having a macroscopic number of bosons enter a single quantum state and form a macroscopic, coherent matter wave. Remarkably, the effect of interparticle repulsion is to lead to quantum mechanical exchange interactions that make that state robust, since the exchange interactions add coherently.

  10. A One-Pot Tandem Strategy in Catalytic Asymmetric Vinylogous Aldol Reaction of Homoallylic Alcohols.

    PubMed

    Hou, Xufeng; Jing, Zhenzhong; Bai, Xiangbin; Jiang, Zhiyong

    2016-01-01

    Reported is a rationally-designed one-pot sequential strategy that allows homoallylic alcohols to be employed in a catalytic, asymmetric, direct vinylogous aldol reaction with a series of activated acyclic ketones, including trifluoromethyl ketones, γ-ketoesters, and α-keto phosphonates, in high yields (up to 95%) with excellent regio- and enantio-selectivity (up to 99% ee). This modular combination, including Jones oxidation and asymmetric organocatalysis, has satisfactory compatibility and reliability even at a 20 mmol scale, albeit without intermediary purification. PMID:27355935

  11. Ligand-Promoted, Boron-Mediated Chemoselective Carboxylic Acid Aldol Reaction.

    PubMed

    Nagai, Hideoki; Morita, Yuya; Shimizu, Yohei; Kanai, Motomu

    2016-05-01

    The first carboxylic acid selective aldol reaction mediated by boron compounds and a mild organic base (DBU) was developed. Inclusion of electron-withdrawing groups in the amino acid derivative ligands reacted with BH3·SMe2 forms a boron promoter with increased Lewis acidity at the boron atom and facilitated the carboxylic acid selective enolate formation, even in the presence of other carbonyl groups such as amides, esters, ketones, or aliphatic aldehydes. The remarkable ligand effect led to the broad substrate scope including biologically relevant compounds. PMID:27104352

  12. Furan production from glycoaldehyde over HZSM-5

    DOE PAGES

    Kim, Seonah; Evans, Tabitha J.; Mukarakate, Calvin; Bu, Lintao; Beckham, Gregg T.; Nimlos, Mark R.; Paton, Robert S.; Robichaud, David J.

    2016-04-03

    Catalytic fast pyrolysis of biomass over zeolite catalysts results primarily in aromatic (e.g. benzene, toluene, xylene) and olefin products. However, furans are a higher value intermediate for their ability to be readily transformed into gasoline, diesel, and chemicals. Here we investigate possible mechanisms for the coupling of glycoaldehyde, a common product of cellulose pyrolysis, over HZSM-5 for the formation of furans. Experimental measurements of neat glycoaldehyde over a fixed bed of HZSM-5 confirm furans (e.g. furanone) are products of this reaction at temperatures below 300 degrees C with several aldol condensation products as co-products (e.g. benzoquinone). However, under typical catalyticmore » fast pyrolysis conditions (>400 degrees C), further reactions occur that lead to the usual aromatic product slate. ONIOM calculations were utilized to identify the pathway for glycoaldehyde coupling toward furanone and hydroxyfuranone products with dehydration reactions serving as the rate determining steps with typical intrinsic reaction barriers of 40 kcal mol-1. The reaction mechanisms for glycoaldehyde will likely be similar to that of other small oxygenates such as acetaldehyde, lactaldehyde, and hydroxyacetone and this study provides a generalizable mechanism of oxygenate coupling and furan formation over zeolite catalysts.« less

  13. A new method for rapid determination of indole-3-carbinol and its condensation products in nutraceuticals using core-shell column chromatography method.

    PubMed

    Fibigr, Jakub; Šatínský, Dalibor; Havlíková, Lucie; Solich, Petr

    2016-02-20

    Indole-3-carbinol is a natural glucosinolate known for prevention of human breast, prostate and other types of cancer and it started to be used in commercial preparations, as food supplements. However no analytical method has been proposed for quality control of nutraceuticals with this substance yet. In this paper a new high-performance liquid chromatography (HPLC) method using core-shell column for separation of indole-3-carbinol and its condensation/degradation products was developed and used for the quantitative determination of indole-3-carbinol in nutraceuticals. Separation of indole-3-carbinol, its condensation/degradation products and internal standard ethylparaben was performed on the core-shell column Kinetex 5μ XB-C18 100A (100×4.6mm), particle size 5.0μm, with mobile phase acetonitrile/water according to the gradient program at a flow rate of 1.25mLmin(-1) and at temperature 50°C. The detection wavelength was set at 270nm. Under the optimal chromatographic conditions good linearity of determination was achieved. Available commercial samples of nutraceuticals were extracted with 100% methanol using ultrasound bath. A 5-μL sample volume of the supernatant was directly injected into the HPLC system. The developed method provided rapid and accurate tool for quality control of nutraceuticals based on cruciferous vegetable extracts with indole-3-carbinol content. The presented study showed that the declared content of indole-3-carbinol significantly varied in the different nutraceuticals available on the market. Two analyzed preparations showed the presence of condensation/degradation products of indole-3-carbinol which were not officially declared by the manufacturer. Moreover, further two analyzed nutraceutical preparations showed absolutely no content of declared amount of indole-3-carbinol.

  14. Compounds and methods for the production of long chain hydrocarbons from biological sources

    DOEpatents

    Gordon, John Cameron; Silks, Louis A; Sutton, Andrew D; Wu, Ruilian; Schlaf, Marcel; Waldie, Fraser; West, Ryan; Collias, Dimitris Ioannis

    2016-08-23

    The present invention is directed to the preparation of oxygenated, unsaturated hydrocarbon compounds, such as derivatives of furfural or hydroxymethyl furfural produced by aldol condensation with a ketone or a ketoester, as well as methods of deoxidatively reducing those compounds with hydrogen under acidic conditions to provide saturated hydrocarbons useful as fuels.

  15. Rh(III)-catalyzed dehydrogenative alkylation of (hetero)arenes with allylic alcohols, allowing aldol condensation to indenes.

    PubMed

    Shi, Zhuangzhi; Boultadakis-Arapinis, Mélissa; Glorius, Frank

    2013-07-25

    Efficient Rh(III)-catalyzed C-H activation of different classes of (hetero)arenes such as 2-phenylpyridine, indoles, aryl ketones and acetanilide and their dehydrogenative cross-coupling with allylic alcohols are described. Several important skeletons such as β-aryl aldehydes and ketones, 2-acetylindenes, 3,4-dihydro-1H-quinolin-2-one and quinoline could be produced using this protocol. PMID:23765402

  16. Genotypic variation for condensed tannin production in trembling aspen (POPULUS TREMULOIDES, salicaceae) under elevated CO2 and in high- and low-fertility soil.

    PubMed

    Mansfield, J L; Curtis, P S; Zak, D R; Pregitzer, K S

    1999-08-01

    The carbon/nutrient balance hypothesis suggests that leaf carbon to nitrogen ratios influence the synthesis of secondary compounds such as condensed tannins. We studied the effects of rising atmospheric carbon dioxide on carbon to nitrogen ratios and tannin production. Six genotypes of Populus tremuloides were grown under elevated and ambient CO(2) partial pressure and high- and low-fertility soil in field open-top chambers in northern lower Michigan, USA. During the second year of exposure, leaves were harvested three times (June, August, and September) and analyzed for condensed tannin concentration. The carbon/nutrient balance hypothesis was supported overall, with significantly greater leaf tannin concentration at high CO(2) and low soil fertility compared to ambient CO(2) and high soil fertility. However, some genotypes increased tannin concentration at elevated compared to ambient CO(2), while others showed no CO(2) response. Performance of lepidopteran leaf miner (Phyllonorycter tremuloidiella) larvae feeding on these plants varied across genotypes, CO(2), and fertility treatments. These results suggest that with rising atmospheric CO(2), plant secondary compound production may vary within species. This could have consequences for plant-herbivore and plant-microbe interactions and for the evolutionary response of this species to global climate change.

  17. Phase engineering of Schrodinger cat states and nonadiabatic production of squeezed states in Bose-Einstein Condensates in multiple wells

    NASA Astrophysics Data System (ADS)

    Leung, Mary Ann

    2004-03-01

    We propose a model for the generation of Schrödinger cat states of BEC in multiple wells, and also show how squeezed states can be produced nonadiabatically. The condensate in the multiple well evolves, starting with a certain initial phase difference between the neighboring wells, to a state with a well defined entanglement. We propose a general formula for the initial phase difference: j 2 pi/N where j=1,2,..,N-1, and N is the number of wells. We show the generation of cat states for these different phase configurations in two, three and four wells, and thus generalize this method to any number of wells, even or odd. In addition to the macroscopic superposition states, the method can also be used to generate squeezed states in a nonadiabatic fashion. This work was supported by NSF grant PHY-0140091 and the Computational Science Graduate Fellowship program.

  18. Spatial coherence of a polariton condensate.

    PubMed

    Deng, Hui; Solomon, Glenn S; Hey, Rudolf; Ploog, Klaus H; Yamamoto, Yoshihisa

    2007-09-21

    We perform Young's double-slit experiment to study the spatial coherence properties of a two-dimensional dynamic condensate of semiconductor microcavity polaritons. The coherence length of the system is measured as a function of the pump rate, which confirms a spontaneous buildup of macroscopic coherence in the condensed phase. An independent measurement reveals that the position and momentum uncertainty product of the condensate is close to the Heisenberg limit. An experimental realization of such a minimum uncertainty wave packet of the polariton condensate opens a door to coherent matter-wave phenomena such as Josephson oscillation, superfluidity, and solitons in solid state condensate systems.

  19. Condensation heat transfer

    NASA Astrophysics Data System (ADS)

    Rose, J. W.

    The paper gives a brief description of some of the better understood aspects of condensation heat transfer and includes discussion of the liquid-vapour interface, natural and forced convection laminar film condensation and dropwise condensation.

  20. Condensation in Nanoporous Packed Beds.

    PubMed

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

  1. Epimerization in peptide thioester condensation.

    PubMed

    Teruya, Kenta; Tanaka, Takeyuki; Kawakami, Toru; Akaji, Kenichi; Aimoto, Saburo

    2012-11-01

    Peptide segment couplings are now widely utilized in protein chemical synthesis. One of the key structures for the strategy is the peptide thioester. Peptide thioester condensation, in which a C-terminal peptide thioester is selectively activated by silver ions then condensed with an amino component, is a powerful tool. But the amino acid adjacent to the thioester is at risk of epimerization. During the preparation of peptide thioesters by the Boc solid-phase method, no substantial epimerization of the C-terminal amino acid was detected. Epimerization was, however, observed during a thioester-thiol exchange reaction and segment condensation in DMSO in the presence of a base. In contrast, thioester-thiol exchange reactions in aqueous solutions gave no epimerization. The epimerization during segment condensation was significantly suppressed with a less polar solvent that is applicable to segments in thioester peptide condensation. These results were applied to a longer peptide thioester condensation. The epimer content of the coupling product of 89 residues was reduced from 27% to 6% in a condensation between segments of 45 and 44 residues for the thioester and the amino component, respectively.

  2. Condensation in Nanoporous Packed Beds.

    PubMed

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization. PMID:27115446

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Optimized Bose-Einstein-condensate production in a dipole trap based on a 1070-nm multifrequency laser: Influence of enhanced two-body loss on the evaporation process

    SciTech Connect

    Lauber, T.; Kueber, J.; Wille, O.; Birkl, G.

    2011-10-15

    We present an optimized strategy for the production of tightly confined Bose-Einstein condensates (BEC) of {sup 87}Rb in a crossed dipole trap with direct loading from a magneto-optical trap. The dipole trap is created with light of a multifrequency fiber laser with a center wavelength of 1070 nm. Evaporative cooling is performed by ramping down the laser power only. A comparison of the resulting atom number in an almost pure BEC to the initial atom number and the value for the gain in phase space density per atom lost confirm that this straightforward strategy is very efficient. We observe that the temporal characteristics of evaporation sequence are strongly influenced by power-dependent two-body losses resulting from enhanced optical pumping to the higher-energy hyperfine state. We characterize these losses and compare them to results obtained with a single-frequency laser at 1030 nm.

  5. Condensation model for the ESBWR passive condensers

    SciTech Connect

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

    2012-07-01

    In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

  6. Inhibition of hydrogen sulfide, methane, and total gas production and sulfate-reducing bacteria in in vitro swine manure by tannins, with focus on condensed quebracho tannins.

    PubMed

    Whitehead, Terence R; Spence, Cheryl; Cotta, Michael A

    2013-09-01

    Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use. Odor and emissions produced during storage have increased the tension among rural neighbors and among urban and rural residents. Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacteria populations during storage. In the current study, the inhibitory effects of condensed quebracho tannins on in vitro swine manure for reduction of microbial activity and reduced production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria (SRB), was examined. Swine manure was collected from a local swine facility, diluted in anaerobic buffer, and mixed with 1 % w/v fresh feces. This slurry was combined with quebracho tannins, and total gas and hydrogen sulfide production was monitored over time. Aliquots were removed periodically for isolation of DNA to measure the SRB populations using quantitative PCR. Addition of tannins reduced overall gas, hydrogen sulfide, and methane production by greater than 90 % after 7 days of treatment and continued to at least 28 days. SRB population was also significantly decreased by tannin addition. qRT-PCR of 16S rDNA bacteria genes showed that the total bacterial population was also decreased in these incubations. These results indicate that the tannins elicited a collective effect on the bacterial population and also suggest a reduction in the population of methanogenic microorganisms as demonstrated by reduced methane production in these experiments. Such a generalized effect could be extrapolated to a reduction in other odor-associated emissions during manure storage.

  7. Wilson-line and color charge density correlators and the production of {eta}{sup '} in the color glass condensate for pp and pA collisions

    SciTech Connect

    Fillion-Gourdeau, Francois; Jeon, Sangyong

    2009-02-15

    We compute the inclusive differential cross section production of the pseudoscalar meson {eta}{sup '} in high-energy proton-proton (pp) and proton-nucleus (pA) collisions. We use an effective coupling between gluons and {eta}{sup '} meson to derive a reduction formula that relates the {eta}{sup '} production to a field-strength tensor correlator. For pA collisions, we take into account saturation effects on the nucleus side by using the color glass condensate formalism to evaluate this correlator. We derive new results for Wilson-line color charge correlators in the McLerran-Venugopalan model needed in the computation of {eta}{sup '} production. The unintegrated parton distribution functions are used to characterize the gluon distribution inside protons. We show that in pp collisions, the cross section depends on the parametrization of unintegrated parton distribution functions, and thus it can be used to put constraints on these distributions. We also demonstrate that in pA collisions, the cross section is sensitive to saturation effects, so it can be utilized to estimate the value of the saturation scale.

  8. Highly Stereoselective and Scalable anti-Aldol Reactions using N-(p-dodecylphenylsulfonyl)-2-Pyrrolidinecarboxamide: Scope and Origins of Stereoselectivities

    PubMed Central

    Yang, Hua; Mahapatra, Subham; Cheong, Paul Ha-Yeon; Carter, Rich G.

    2010-01-01

    A highly enantio- and diastereoselective anti-aldol process (up to >99% ee, >99:1 dr) catalyzed by a proline mimetic – N-(p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide – has been developed. Catalyst loading as low as 2 mol% can be employed. Use of industry-friendly solvents for this transformation as well as neat reaction conditions have been demonstrated. The scope of this transformation on a range of aldehydes and ketones is explored. Density Functional Theory computations reveal that the origins of enhanced diastereoselectivity is due to the presence of non-classical hydrogen bonds between the sulfonamide, the electrophile and the catalyst enamine that favor the major Anti-Re aldol TS in the Houk-List model. PMID:20932013

  9. Expansion in condensates

    SciTech Connect

    Chakrabarti, J.; Sajjad Zahir, M.

    1985-03-01

    We show that the product of local current operators in quantum chromodynamics (QCD), when expanded in terms of condensates, such as psi-barpsi, G/sup a//sub munu/ G/sup a//sub munu/, psi-barGAMMA psipsi-barGAMMApsi, f/sub a/bcG/sup a//sub munu/G/sup b//sub nualpha/ x G/sup c//sub alphamu/, etc., yields a series in Planck's constant. This, however, provides no hint that the higher terms in such an expansion may be less significant.

  10. 1,6-asymmetric induction in boron-mediated aldol reactions: application to a practical total synthesis of (+)-discodermolide.

    PubMed

    Paterson, Ian; Delgado, Oscar; Florence, Gordon J; Lyothier, Isabelle; Scott, Jeremy P; Sereinig, Natascha

    2003-01-01

    By relying solely on substrate-based stereocontrol, a practical total synthesis of the microtubule-stabilizing anticancer agent (+)-discodermolide has been realized. This exploits a novel aldol bond construction with 1,6-stereoinduction from the boron enolate of (Z)-enone 3 in addition to aldehyde 2. The 1,3-diol 7 is employed as a common building block for the C(1)-C(5), C(9)-C(16), and C(17)-C(24) subunits. [reaction--see text

  11. 7 CFR 58.238 - Condensed storage tanks.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Condensed storage tanks. 58.238 Section 58.238... Procedures § 58.238 Condensed storage tanks. (a) Excess production of condensed product over that which the dryer will take continuously from the pans should be bypassed through a cooler into a storage tank at...

  12. 7 CFR 58.238 - Condensed storage tanks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Condensed storage tanks. 58.238 Section 58.238... Procedures § 58.238 Condensed storage tanks. (a) Excess production of condensed product over that which the dryer will take continuously from the pans should be bypassed through a cooler into a storage tank at...

  13. 7 CFR 58.238 - Condensed storage tanks.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Condensed storage tanks. 58.238 Section 58.238... Procedures § 58.238 Condensed storage tanks. (a) Excess production of condensed product over that which the dryer will take continuously from the pans should be bypassed through a cooler into a storage tank at...

  14. 7 CFR 58.238 - Condensed storage tanks.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Condensed storage tanks. 58.238 Section 58.238... Procedures § 58.238 Condensed storage tanks. (a) Excess production of condensed product over that which the dryer will take continuously from the pans should be bypassed through a cooler into a storage tank at...

  15. Genetic toxicology and toxicogenomic analysis of three cigarette smoke condensates in vitro reveals few differences among full-flavor, blonde, and light products

    PubMed Central

    Yauk, Carole L; Williams, Andrew; Buick, Julie K; Chen, Guosheng; Maertens, Rebecca M; Halappanavar, Sabina; White, Paul A

    2012-01-01

    Cigarette smoking leads to various detrimental health outcomes. Tobacco companies produce different brands of cigarettes that are marketed as reduced harm tobacco products. Early examples included “light” cigarettes, which differ from regular cigarettes due to filter ventilation and/or differences in chemical constituents. In order to establish baseline similarities and differences among different tobacco brands available in Canada, the present study examined the cytotoxicity, mutagenicity, clastogenicity, and gene expression profiles of cigarette smoke condensate (CSC) from three tobacco products, encompassing a full-flavor, blonde, and “light” variety. Using the Salmonella mutagenicity assay, we confirmed that the three CSCs are mutagenic, and that the potency is related to the presence of aromatic amines. Using the Muta™Mouse FE1 cell line we determined that the CSCs were clastogenic and cytotoxic, but nonmutagenic, and the results showed few differences in potencies among the three brands. There were no clear brand-specific changes in gene expression; each brand yielded highly similar expression profiles within a time point and concentration. The molecular pathways and biological functions affected by exposure included xenobiotic metabolism, oxidative stress, DNA damage response, cell cycle arrest and apoptosis, as well as inflammation. Thus, there was no appreciable difference in toxicity or gene expression profiles between regular brands and products marketed as “light,” and hence no evidence of reduced harm. The work establishes baseline CSC cytotoxicity, mutagenicity, and expression profiles that can be used as a point of reference for comparison with data generated for products marketed as reduced harm and/or modified risk tobacco products. Mol. Mutagen. 2012. © 2012 Wiley Periodicals, Inc.† PMID:22431010

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

    PubMed

    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. PMID:26169629

  17. Condensed-phase pyrolysis of n-tetradecane at elevated pressures for long duration -- Product distribution and reaction mechanisms

    SciTech Connect

    Song, C.; Lai, W.C.; Schobert, H.H. . Fuel Science Program)

    1994-03-01

    For pyrolysis of n-tetradecane at 450 C under elevated pressures (about 2--9 MPa) for 6--480 min, the major products in the early stage are n-alkanes in the carbon number range of C[sub 1]-C[sub 11] and 1-alkenes in the carbon number range of C[sub 2]-C[sub 14]. Formation of the olefinic product with 13 carbon atoms is very limited, but 1-C[sub 12]H[sub 24] is as abundant as the 1-alkenes in the range of C[sub 2]-C[sub 11]. As compared to the well-known gas-phase pyrolysis, the molar ratios of alkenes to alkanes are much smaller ([le]1), except the ratio for the group with 12 carbon atoms where the 1-C[sub 12]H[sub 24]/n-C[sub 12]H[sub 26] ratio can be as high as 9 in the early stage. This is because 1-C[sub 12]H[sub 24] is produced from [beta]-scission of a secondary 4-C[sub 14]H[sub 29] radical, whereas n-C[sub 12]H[sub 26] is formed from a primary 1-C[sub 14]H[sub 29] radical, whose population is much less than the secondary radical due to both higher activation energy and the competing isomerization reaction. There appeared a preferential formation of 1-C[sub 6]H[sub 12] and 1-C[sub 5]H[sub 10] among the 1-alkenes formed after 12 min. This may be attributed to the 1,5-shift and 1,4-shift isomerization of primary radicals formed during tetradecane pyrolysis. The peak of carbon number distribution shifts toward 2 for paraffinic products and toward 3 for olefinic products, and the ratios of alkenes to alkanes decrease with increasing residence time up to 60 min. The general reaction mechanism is characterized by the one-step decomposition of secondary radicals and the 1,5 and 1,4-shift isomerization of primary radicals to secondary radicals. The substrate alkane molecules are the source for hydrogen abstraction in the early stage, but in the later stages the olefinic products also undergo the H-abstraction reactions, which lead to the formation of cyclic alkenes/alkanes and alkylaromatics.

  18. Bio-oil fractionation and condensation

    DOEpatents

    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.

  19. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    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

  20. Rational nanoconjugation improves biocatalytic performance of enzymes: aldol addition catalyzed by immobilized rhamnulose-1-phosphate aldolase.

    PubMed

    Ardao, Inés; Comenge, Joan; Benaiges, M Dolors; Álvaro, Gregorio; Puntes, Víctor F

    2012-04-17

    Gold nanoparticles (AuNPs) are attractive materials for the immobilization of enzymes due to several advantages such as high enzyme loading, absence of internal diffusion limitations, and Brownian motion in solution, compared to the conventional immobilization onto porous macroscopic supports. The affinity of AuNPs to different groups present at the protein surface enables direct enzyme binding to the nanoparticle without the need of any coupling agent. Enzyme activity and stability appear to be improved when the biocatalyst is immobilized onto AuNPs. Rhamnulose-1-phosphate aldolase (RhuA) was selected as model enzyme for the immobilization onto AuNPs. The enzyme loading was characterized by four different techniques: surface plasmon resonance (SPR) shift and intensity, dynamic light scattering (DLS), and transmission electron microscopy (TEM). AuNPs-RhuA complexes were further applied as biocatalyst of the aldol addition reaction between dihydroxyacetone phosphate (DHAP) and (S)-Cbz-alaninal during two reaction cycles. In these conditions, an improved reaction yield and selectivity, together with a fourfold activity enhancement were observed, as compared to soluble RhuA. PMID:22428999

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

    PubMed

    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.

  2. Condensates in Jovian Atmospheres

    NASA Technical Reports Server (NTRS)

    West, R.

    1999-01-01

    Thermochemical equilibrium theory which starts with temperature/pressure profiles, compositional information and thermodynamic data for condensable species in the jovian planet atmospheres predicts layers of condensate clouds in the upper troposphere.

  3. From 2 + 2 to 8 + 8 Condensation Products of Diamine and Dialdehyde: Giant Container-Shaped Macrocycles for Multiple Anion Binding.

    PubMed

    Gregoliński, Janusz; Ślepokura, Katarzyna; Paćkowski, Tomasz; Panek, Jarosław; Stefanowicz, Piotr; Lisowski, Jerzy

    2016-07-01

    The combination of 2,6-diformylpyridine and trans-1,2-diaminocyclopentane fragments results in 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic imine condensation products. These imines can be reduced to the corresponding 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic amines. The X-ray crystal structures of their protonated derivatives show a rich variety of macrocycle conformations ranging from a stepped 2 + 2 macrocycle to a multiply folded 8 + 8 macrocycle of globular shape. These compounds bind anions via hydrogen bonds: two chloride anions are bound above and below the macrocyclic ring of the 2 + 2 amine, one chloride anion is bound approximately in the center of the 3 + 3 macrocycle, and two chloride anions are deeply buried inside a folded container-shaped 4 + 4 macrocycle, while in the case of the previously reported 6 + 6 amine four chloride anions and two solvent molecules are buried inside a container-shaped macrocycle. Yet another situation was observed for a multiply folded protonated 8 + 8 macrocycle which binds six sulfate anions; two of them are deeply buried inside the container structure while four anions interact with the clefts at the surface of the container.

  4. From 2 + 2 to 8 + 8 Condensation Products of Diamine and Dialdehyde: Giant Container-Shaped Macrocycles for Multiple Anion Binding.

    PubMed

    Gregoliński, Janusz; Ślepokura, Katarzyna; Paćkowski, Tomasz; Panek, Jarosław; Stefanowicz, Piotr; Lisowski, Jerzy

    2016-07-01

    The combination of 2,6-diformylpyridine and trans-1,2-diaminocyclopentane fragments results in 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic imine condensation products. These imines can be reduced to the corresponding 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic amines. The X-ray crystal structures of their protonated derivatives show a rich variety of macrocycle conformations ranging from a stepped 2 + 2 macrocycle to a multiply folded 8 + 8 macrocycle of globular shape. These compounds bind anions via hydrogen bonds: two chloride anions are bound above and below the macrocyclic ring of the 2 + 2 amine, one chloride anion is bound approximately in the center of the 3 + 3 macrocycle, and two chloride anions are deeply buried inside a folded container-shaped 4 + 4 macrocycle, while in the case of the previously reported 6 + 6 amine four chloride anions and two solvent molecules are buried inside a container-shaped macrocycle. Yet another situation was observed for a multiply folded protonated 8 + 8 macrocycle which binds six sulfate anions; two of them are deeply buried inside the container structure while four anions interact with the clefts at the surface of the container. PMID:27304017

  5. Condensed astatine: monatomic and metallic.

    PubMed

    Hermann, Andreas; Hoffmann, Roald; Ashcroft, N W

    2013-09-13

    The condensed matter properties of the nominal terminating element of the halogen group with atomic number 85, astatine, are as yet unknown. In the intervening more than 70 years since its discovery significant advances have been made in substrate cooling and the other techniques necessary for the production of the element to the point where we might now enquire about the key properties astatine might have if it attained a condensed phase. This subject is addressed here using density functional theory and structural selection methods, with an accounting for relativistic physics that is essential. Condensed astatine is predicted to be quite different in fascinating ways from iodine, being already at 1 atm a metal, and monatomic at that, and possibly a superconductor (as is dense iodine). PMID:24074111

  6. Condensed astatine: monatomic and metallic.

    PubMed

    Hermann, Andreas; Hoffmann, Roald; Ashcroft, N W

    2013-09-13

    The condensed matter properties of the nominal terminating element of the halogen group with atomic number 85, astatine, are as yet unknown. In the intervening more than 70 years since its discovery significant advances have been made in substrate cooling and the other techniques necessary for the production of the element to the point where we might now enquire about the key properties astatine might have if it attained a condensed phase. This subject is addressed here using density functional theory and structural selection methods, with an accounting for relativistic physics that is essential. Condensed astatine is predicted to be quite different in fascinating ways from iodine, being already at 1 atm a metal, and monatomic at that, and possibly a superconductor (as is dense iodine).

  7. Condensed Astatine: Monatomic and Metallic

    NASA Astrophysics Data System (ADS)

    Hermann, Andreas; Hoffmann, Roald; Ashcroft, N. W.

    2013-09-01

    The condensed matter properties of the nominal terminating element of the halogen group with atomic number 85, astatine, are as yet unknown. In the intervening more than 70 years since its discovery significant advances have been made in substrate cooling and the other techniques necessary for the production of the element to the point where we might now enquire about the key properties astatine might have if it attained a condensed phase. This subject is addressed here using density functional theory and structural selection methods, with an accounting for relativistic physics that is essential. Condensed astatine is predicted to be quite different in fascinating ways from iodine, being already at 1 atm a metal, and monatomic at that, and possibly a superconductor (as is dense iodine).

  8. Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

    NASA Astrophysics Data System (ADS)

    Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

    2016-05-01

    A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes

  9. Strange Disoriented Chiral Condensates

    NASA Astrophysics Data System (ADS)

    Abdel-Aziz, Mohamed; Gavin, Sean

    2002-10-01

    Enhancement of omega and anti-omega baryon production in Pb+Pb collisions at the CERN SPS can be explained by the formation of many small regions of disordered chiral condensate. This explanation implies that neutral and charged kaons as well as pions must exhibit novel isospin fluctuations. Fluctuations due to transient behavior of the Polyakov Loop condensate can produce similar phenomena. Kapusta and Gavin have computed the distribution of the fraction of neutral pions and kaons from such regions. We proposed robust statistical observables that can be used to extract the novel isospin fluctuations from background contributions in neutral/charged pion and K-short/K-charged correlation measurements at RHIC and LHC. The STAR experiment is currently examining K-short/K-charged correlations. Note that Pruneau, Voloshin and Gavin have proposed similar observables to study net-charge fluctuations. To obtain a baseline for comparison to RHIC and SPS experiments, Abdel-Aziz and Gavin compute these observables using numerical simulations using HIJING and URQMD event generators. We also obtain limits on the size and number of disordered regions by comparing to photon and charged-pion searches from WA98 and other SPS experiments. We will compare to the first results from STAR K-short/K-charged analysis.

  10. Divergent Synthesis of Multisubstituted Tetrahydrofurans and Pyrrolidines via Intramolecular Aldol-type Trapping of Onium Ylide Intermediates.

    PubMed

    Jing, Changcheng; Xing, Dong; Gao, Lixin; Li, Jia; Hu, Wenhao

    2015-12-21

    This paper reports a divergent strategy for the synthesis of multisubstituted tetrahydrofurans and pyrrolidines, starting from easily accessible β-hydroxyketones or β-aminoketones to react with diazo compounds. Under Rh(II) catalysis, this transformation is proposed to proceed through a metal-carbene-induced oxonium ylide or ammonium ylide formation followed by an intramolecular aldol-type trapping of these active intermediates. A series of highly substituted tetrahydrofurans and pyrrolidines are synthesized in high yields with good to excellent diastereoselectivities. Preliminary biological evaluations revealed that both types of heterocycles show good PTP1B inhibitory activities. PMID:26592374

  11. Gold-catalyzed construction of two adjacent quaternary stereocenters via sequential C-H functionalization and aldol annulation.

    PubMed

    Yu, Zhunzhun; Qiu, Haile; Liu, Lu; Zhang, Junliang

    2016-02-01

    Herein, a novel and efficient gold-catalyzed intermolecular C(sp(2))-H functionalization (Friedel-Crafts alkylation) and aldol annulation strategy is presented. This cascade process allows the synthesis of a series of indanol and tetrahydronaphthalenol derivatives with two adjacent quaternary stereocenters. The attractive reaction features are the use of readily available starting materials, good diastereoselectivity, good functional-group tolerance and mild reaction conditions. Furthermore, preliminary results indicate that this transformation is amenable to enantioselectivitive synthesis with further chiral ligand screening and design. PMID:26725981

  12. Stereopentads derived from a sequence of Mukaiyama aldolization and free radical reduction on alpha-methyl-beta-alkoxy aldehydes: a general strategy for efficient polypropionate synthesis.

    PubMed

    Brazeau, Jean-François; Mochirian, Philippe; Prévost, Michel; Guindon, Yvan

    2009-01-01

    In a stereodivergent manner, all 16 diastereomeric stereopentads 7-22 were synthesized starting with alpha-methyl-beta-alkoxy aldehydes 25 and 27. We designed an approach based on a sequence of a Mukaiyama aldolization with enoxysilane 24 followed by a hydrogen transfer reaction. Recent advancements concerning these reactions are described, and novel key intermediates are characterized in the aldol step. The synthesis of C(1)-C(11) fragment 60 of zincophorin, which contains a synthetically challenging stereopentad unit, is described attesting the usefulness of our strategy.

  13. Proceedings: Condenser technology conference

    SciTech Connect

    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 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.

  14. Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

  15. Compact setup for the production of (87)Rb |F = 2, m = + 2〉 Bose-Einstein condensates in a hybrid trap.

    PubMed

    Nolli, Raffaele; Venturelli, Michela; Marmugi, Luca; Wickenbrock, Arne; Renzoni, Ferruccio

    2016-08-01

    We present a compact experimental apparatus for Bose-Einstein condensation of (87)Rb in the |F  =  2, mF = + 2〉 state. A pre-cooled atomic beam of (87)Rb is obtained by using an unbalanced magneto-optical trap, allowing controlled transfer of trapped atoms from the first vacuum chamber to the science chamber. Here, atoms are transferred to a hybrid trap, as produced by overlapping a magnetic quadrupole trap with a far-detuned optical trap with crossed beam configuration, where forced radiofrequency evaporation is realized. The final evaporation leading to Bose-Einstein condensation is then performed by exponentially lowering the optical trap depth. Control and stabilization systems of the optical trap beams are discussed in detail. The setup reliably produces a pure condensate in the |F = 2, mF = + 2〉 state in 50 s, which includes 33 s loading of the science magneto-optical trap and 17 s forced evaporation. PMID:27587095

  16. Compact setup for the production of 87Rb |F = 2, mF = + 2> Bose-Einstein condensates in a hybrid trap

    NASA Astrophysics Data System (ADS)

    Nolli, Raffaele; Venturelli, Michela; Marmugi, Luca; Wickenbrock, Arne; Renzoni, Ferruccio

    2016-08-01

    We present a compact experimental apparatus for Bose-Einstein condensation of 87Rb in the |F = 2, mF = + 2> state. A pre-cooled atomic beam of 87Rb is obtained by using an unbalanced magneto-optical trap, allowing controlled transfer of trapped atoms from the first vacuum chamber to the science chamber. Here, atoms are transferred to a hybrid trap, as produced by overlapping a magnetic quadrupole trap with a far-detuned optical trap with crossed beam configuration, where forced radiofrequency evaporation is realized. The final evaporation leading to Bose-Einstein condensation is then performed by exponentially lowering the optical trap depth. Control and stabilization systems of the optical trap beams are discussed in detail. The setup reliably produces a pure condensate in the |F = 2, mF = + 2> state in 50 s, which includes 33 s loading of the science magneto-optical trap and 17 s forced evaporation.

  17. Compact setup for the production of (87)Rb |F = 2, m = + 2〉 Bose-Einstein condensates in a hybrid trap.

    PubMed

    Nolli, Raffaele; Venturelli, Michela; Marmugi, Luca; Wickenbrock, Arne; Renzoni, Ferruccio

    2016-08-01

    We present a compact experimental apparatus for Bose-Einstein condensation of (87)Rb in the |F  =  2, mF = + 2〉 state. A pre-cooled atomic beam of (87)Rb is obtained by using an unbalanced magneto-optical trap, allowing controlled transfer of trapped atoms from the first vacuum chamber to the science chamber. Here, atoms are transferred to a hybrid trap, as produced by overlapping a magnetic quadrupole trap with a far-detuned optical trap with crossed beam configuration, where forced radiofrequency evaporation is realized. The final evaporation leading to Bose-Einstein condensation is then performed by exponentially lowering the optical trap depth. Control and stabilization systems of the optical trap beams are discussed in detail. The setup reliably produces a pure condensate in the |F = 2, mF = + 2〉 state in 50 s, which includes 33 s loading of the science magneto-optical trap and 17 s forced evaporation.

  18. Acetone cataluminescence as an indicator for evaluation of heterogeneous base catalysts in biodiesel production.

    PubMed

    Zhang, Lijuan; Chen, Yingchun; He, Nan; Lu, Chao

    2014-01-01

    Rapid and effective evaluation techniques for heterogeneous base catalysts in biodiesel production are highly desirable with increased global demand for biofuels. In this work, we have discovered direct connections between the number of medium-strength basic sites of heterogeneous base catalysts in biodiesel production and cataluminescence intensity in acetone aldol condensation reactions. Accordingly, acetone cataluminescence has been employed as an indicator for rapid evaluation of heterogeneous base catalysts in biodiesel production. Its practical feasibility has been first established using commercially available heterogeneous base catalysts in biodiesel production (including MgO, Al2O3, TiO2, and ZnO), indicating a good matching between the proposed cataluminescence screening method and routine temperature-programmed desorption measurements. Subsequently, the proposed cataluminescence method can be used to effectively distinguish a set of layered double hydroxides and layered double oxide with fewer differences of basic sites, and the relative standard deviation (RSD) of the proposed method is 2.90%. The developed cataluminescence platform is able to take advantage of low cost, simple configuration, fast response, long-term stability, and easy operation. This work has a great potential in distinguishing weak/strong basic sites and even acidic sites of each catalyst system by tuning molecular probes. PMID:24325398

  19. All-optical scheme for strongly enhanced production of a Bose-Einstein condensate of dipolar molecules in the vibronic ground state

    SciTech Connect

    Mackie, Matt; Debrosse, Catherine

    2010-04-15

    We consider two-color heteronuclear photoassociation of a dual-species Bose-Einstein condensate into a Bose-Einstein condensate of dipolar molecules in the J=1 vibronic ground state, where a free-ground laser couples atoms directly to the ground state and a free-bound laser couples the atoms to an electronically excited state. This problem raises an interest because heteronuclear photoassociation from atoms to near-ground-state molecules is limited by the small size of the target state. Nevertheless, the addition of the electronically excited state creates a second pathway for creating molecules in the vibronic ground state, leading to quantum interference between direct photoassociation and photoassociation via the excited molecular state, as well as a dispersivelike shift of the free-ground resonance position. Using LiNa as an example, these results are shown to depend on the detuning and intensity of the free-bound laser, as well as the semiclassical size of both molecular states. Whereas strong enhancement enables saturation of the free-ground transition, coherent conversion from a two-species condensate of atoms to a condensate of dipolar molecules in the vibronic ground state is only possible for a limited range of free-bound detunings near resonance.

  20. Tandem carbon-carbon bond insertion and intramolecular aldol reaction of benzyne with aroylacetones: novel formation of 4,4'-disubstituted 1,1'-binaphthols.

    PubMed

    Okuma, Kentaro; Itoyama, Ryoichi; Sou, Ayumi; Nagahora, Noriyoshi; Shioj, Kosei

    2012-11-21

    An efficient route to 4-aryl-2-naphthols from arynes and aroylacetones was developed by carbon-carbon bond insertion followed by an intramolecular aldol reaction and dehydration. Benzyne derived from 2-(trimethylsilyl)phenyl triflate reacted with benzoylacetones in refluxing acetonitrile to give 4-aryl-2-naphthols and 3-aryl-1-naphthols.

  1. CALIX[6]ARENE DERIVATIVES BEARING SULFONATE AND ALKYL GROUPS AS SURFACTANTS IN SC(OTF)3-CATALYZED MUKAIYAMA ALDOL REACTIONS IN WATER. (R822668)

    EPA Science Inventory

    Abstract

    Amphiphilic calix[6]arene derivatives 1a¯b were found to be efficient surfactants for Sc(OTf)3-catalyzed Mukaiyama aldol reaction of silyl enol ethers with aldehydes in water. The results indicated t...

  2. THE EFFECTS OF AROMATIC AND ALIPHATIC ANIONIC SURFACTANTS ON SC(OTF)3-CATALYZED MUKAIYAMA ALDOL REACTION IN WATER. (R822668)

    EPA Science Inventory

    Abstract

    Aromatic (2c and 2d) and aliphatic (2a and 2b) anionic surfactants were employed in Sc(OTf)3-catalyzed aldol reactions of some labile silyl enol ethers (3a and

  3. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A; Dakin, B.; Hoeschele, M.

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  4. Geothermal steam condensate reinjection

    NASA Technical Reports Server (NTRS)

    Chasteen, A. J.

    1974-01-01

    Geothermal electric generating plants which use condensing turbines and generate and excess of condensed steam which must be disposed of are discussed. At the Geysers, California, the largest geothermal development in the world, this steam condensate has been reinjected into the steam reservoir since 1968. A total of 3,150,000,000 gallons of steam condensate has been reinjected since that time with no noticeable effect on the adjacent producing wells. Currently, 3,700,000 gallons/day from 412 MW of installed capacity are being injected into 5 wells. Reinjection has also proven to be a satisfactory method of disposing of geothermal condensate a Imperial Valley, California, and at the Valles Caldera, New Mexico.

  5. Freeze-Tolerant Condensers

    NASA Technical Reports Server (NTRS)

    Crowley, Christopher J.; Elkouhk, Nabil

    2004-01-01

    Two condensers designed for use in dissipating heat carried by working fluids feature two-phase, self-adjusting configurations such that their working lengths automatically vary to suit their input power levels and/or heat-sink temperatures. A key advantage of these condensers is that they can function even if the temperatures of their heat sinks fall below the freezing temperatures of their working fluids and the fluids freeze. The condensers can even be restarted from the frozen condition. The top part of the figure depicts the layout of the first condenser. A two-phase (liquid and vapor) condenser/vapor tube is thermally connected to a heat sink typically, a radiatively or convectively cooled metal panel. A single-phase (liquid) condensate-return tube (return artery) is also thermally connected to the heat sink. At intervals along their lengths, the condenser/vapor tube and the return artery are interconnected through porous plugs. This condenser configuration affords tolerance of freezing, variable effective thermal conductance (such that the return temperature remains nearly constant, independently of the ultimate sink temperature), and overall pressure drop smaller than it would be without the porous interconnections. An additional benefit of this configuration is that the condenser can be made to recover from the completely frozen condition either without using heaters, or else with the help of heaters much smaller than would otherwise be needed. The second condenser affords the same advantages and is based on a similar principle, but it has a different configuration that affords improved flow of working fluid, simplified construction, reduced weight, and faster recovery from a frozen condition.

  6. Electrolyte vapor condenser

    DOEpatents

    Sederquist, Richard A.; Szydlowski, Donald F.; Sawyer, Richard D.

    1983-01-01

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

  7. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  8. 21 CFR 573.450 - Fermented ammoniated condensed whey.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.450 Fermented ammoniated condensed whey. (a) Identity. The product is... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Fermented ammoniated condensed whey....

  9. 21 CFR 573.450 - Fermented ammoniated condensed whey.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.450 Fermented ammoniated condensed whey. (a) Identity. The product is... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Fermented ammoniated condensed whey....

  10. Ghost condensate busting

    SciTech Connect

    Bilic, Neven; Tupper, Gary B; Viollier, Raoul D E-mail: gary.tupper@uct.ac.za

    2008-09-15

    Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

  11. THE COLOR GLASS CONDENSATE.

    SciTech Connect

    MCLERRAN,L.

    2001-08-26

    The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

  12. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A.; Dakin, B.; Hoeschele, M.

    2012-03-01

    The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

  13. Evolutionary games of condensates in coupled birth-death processes

    NASA Astrophysics Data System (ADS)

    Weber, Markus F.; Knebel, Johannes; Krueger, Torben; Frey, Erwin

    2015-03-01

    Condensation phenomena occur in many systems, both in a classical and a quantum mechanical context. Typically, the entities that constitute a system collectively concentrate in one distinct state during condensation. For example, cooling of an equilibrated bosonic gas may lead to condensation into the quantum ground state. Notably, the mathematical theory of this Bose-Einstein condensation is not limited to quantum theory but was also successfully applied to condensation in random networks. In our work, we follow the opposite path. We apply the theory of evolutionary dynamics to describe condensation in a bosonic system that is driven and dissipative. It was shown that the system may condense into multiple quantum states, but into which states has remained elusive. We find that vanishing of relative entropy production determines these states. We illuminate the physical principles underlying the condensation and show that the condensates do not need to be static but may engage in ``evolutionary games'' with exchange of particles. On the mathematical level, the condensation is described by coupled birth-death processes. The generic structure of these processes implies that our results also apply to condensation in other systems, ranging from population biology to chemical kinetics.

  14. Condensate dark matter stars

    SciTech Connect

    Li, X.Y.; Harko, T.; Cheng, K.S. E-mail: harko@hkucc.hku.hk

    2012-06-01

    We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by M{sub crit} ≈ 2(l{sub a}/1fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2}M{sub s}un and R{sub crit} ≈ 1.1 × 10{sup 6}(l{sub a}/1 fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2} cm respectively, where l{sub a} and m{sub χ} are the scattering length and the mass of dark matter particle, respectively.

  15. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    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. Mineralogy and petrography of amoeboid olivine aggregates from the reduced CV3 chondrites Efremovka, Leoville and Vigarano: Products of nebular condensation, accretion and annealing

    NASA Astrophysics Data System (ADS)

    Komatsu, Mutsumi; Krot, Alexander N.; Petaev, Mikhail I.; Ulyanov, Alexander A.; Keil, Klaus; Miyamoto, Masamichi

    2001-05-01

    Amoeboid olivine aggregates (AOAs) from the reduced CV chondrites Efremovka, Leoville and Vigarano are irregularly-shaped objects, up to 5 mm in size, composed of forsteritic olivine (Fa<10) and a refractory, Ca,Al-rich component. The AOAs are depleted in moderately volatile elements (Mn, Cr, Na, K), Fe,Ni-metal and sulfides and contain no low-Ca pyroxene. The refractory component consists of fine-grained Ca,Al-rich inclusions (CAIs) composed of Al-diopside, anorthite (An100), and magnesium-rich spinel (~1 wt% FeO) or fine-grained intergrowths of these minerals; secondary nepheline and sodalite are very minor. This indicates that AOAs from the reduced CV chondrites are more pristine than those from the oxidized CV chondrites Allende and Mokoia. Although AOAs from the reduced CV chondrites show evidence for high temperature nebular annealing (e.g., forsterite grain boundaries form 120 deg triple junctions) and possibly a minor degree of melting of Al-diopside-anorthite materials, none of the AOAs studied appear to have experienced extensive (>50%) melting. We infer that AOAs are aggregates of high temperature nebular condensates, which formed in CAI-forming regions, and that they were absent from chondrule-forming regions at the time of chondrule formation. The absence of low-Ca pyroxene and depletion in moderately volatile elements (Mn, Cr, Na, K) suggest that AOAs were either removed from CAI-forming regions prior to condensation of these elements and low-Ca pyroxene or gas-solid condensation of low-Ca-pyroxene was kinetically inhibited.

  17. Origins of opposite syn-anti diastereoselectivities in primary and secondary amino acid-catalyzed intermolecular aldol reactions involving unmodified alpha-hydroxyketones.

    PubMed

    Fu, Aiping; Li, Hongliang; Yuan, Shuping; Si, Hongzong; Duan, Yunbo

    2008-07-18

    The effects of different amino acid catalysts on the stereoselectivity of the direct intermolecular aldol reactions between alpha-hydroxyketones and isobutyraldehyde or 4-nitrobenzaldehyde have been studied with the aid of density functional theory methods. The transition states of the crucial C-C bond-forming step with the enamine intermediate addition to the aldehyde for the proline and threonine-catalyzed asymmetric aldol reactions are reported. B3LYP/6-31+G** calculations provide a good explanation for the opposite syn vs anti diastereoselectivity of these two kinds of amino acid catalysts (anti-selectivity for the secondary cyclic amino acids proline, syn-selectivity for the acyclic primary amino acids like threonine). Calculated and observed diastereomeric ratio and enantiomeric excess values are in good agreement. PMID:18549281

  18. PERVAPORATION SEPARATION IMPROVEMENTS VIA FRACTIONAL CONDENSATION (DEPHLEGMATION): IMPACT OF DEPHLEGMATOR DESIGN ON PERFORMANCE

    EPA Science Inventory

    Traditionally, pervaporation systems have been operated using a total condenser to deliver the final permeate liquid product. Over the past two years, we have investigated the use of a condensation process called "dephlegmation" to enhance the separation performance of pervapora...

  19. The Evans Aldol-Prins cyclization: a general and stereoselective method for the synthesis of 2,3,4,5,6-pentasubstituted tetrahydropyrans.

    PubMed

    Álvarez-Méndez, Sergio J; García, Celina; Martín, Víctor S

    2016-02-25

    A general and stereoselective method to synthesize 2,3,4,5,6-pentasubstituted tetrahydropyrans in three steps starting from three different aldehydes is described. Key substrates β,γ-unsaturated N-acyloxazolidin-2-ones were subjected to an "Evans Aldol-Prins" protocol to generate five σ-bonds and five stereocenters in only a one-pot process with yields up to 60% and excellent stereoselectivities.

  20. The role of synergic interaction in transition state formation for the aldol reaction on a metal oxide catalyst: a DFT investigation.

    PubMed

    An, Wei

    2015-09-21

    This contribution highlights an eight-membered ring transition state for the aldol reaction of propanal on O-terminated ZrO2(111) and CeO2(111) surfaces. The relative heights of activation barriers for α-H abstraction and nucleophilic addition are controlled by surface acid-base pair strength. We report the first theoretical evidence of an alternative to the Zimmerman-Traxler model.

  1. Regulated-stereoselective construction of thirteen stereogenic centers necessary for the frame of (+)-discodermolide, based on iterative Lewis acid-promoted aldol reactions.

    PubMed

    Kiyooka, Syun-ichi; Shahid, Kazi Abdus; Goto, Fumitaka; Okazaki, Momotoshi; Shuto, Yoshihiro

    2003-10-17

    The segments C(1)-C(13) and C(15)-C(21) containing the 13 stereogenic centers required for the frame of (+)-discodermolide were synthesized in good to excellent enantio- and diastereoselectivities from a common racemic aldehyde, derived from 2-methyl-1,3-propanediol. The enantioselective aldol reactions of the racemic aldehyde with a silylketene acetal, derived from ethyl 2-bromopropionate, in the presence of chiral oxazaborolidinones, prepared in situ with N-p-toluenesulfonyl-(R)- and -(S)-valine and BH(3).THF, proceeded under kinetic control to give the stereotriads with a high degree of enantioselectivity. Enantioselective (chiral borane) and diastereoselective (BF(3).OEt(2) and TiCl(4)) aldol reactions with the silylketene acetal, coupled with diastereoselective radical debrominations (Bu(3)SnH, Et(3)B, with or without MgBr(2)), were used iteratively. This aldol reaction strategy for the construction of the polypropionate frame dramatically shortened the steps needed for the construction of the final segments.

  2. Preparation and confinement effect of a heterogeneous 9-amino-9-deoxy-epi-cinchonidine organocatalyst for asymmetric aldol addition in aqueous medium.

    PubMed

    Wang, Wei; Ma, Xuebing; Wan, Jingwei; Cao, Jun; Tang, Qian

    2012-05-14

    A series of novel porous zirconium phosphonate-supported 9-amino-9-deoxy-epi-cinchonidines of general formulae Zr(OH)(4-2x)(O(3)PR)(x)·nH(2)O and Zr(HPO(4))(2-x)(O(3)PR)(x)·nH(2)O with the different arm chain lengths (n = 2-6) and mean diameters of approximately 20-40 nm have been prepared as heterogeneous organocatalysts. The different microtextures of zirconium phosphonates were also obtained by using template guest molecules, such as Et(3)N, NaH(2)PO(4) and sodium dodecyl benzene sulfonate. In the heterogeneous asymmetric aldol addition of p-nitrobenzaldehyde to cyclohexanone, excellent catalytic properties were achieved, especially in an aqueous medium. After completing the reaction, those zirconium phosphonate-supported 9-amino-9-deoxy-epi-cinchonidine organocatalysts could be readily recovered in quantitative yield by centrifugation or filtration, and reused for five consecutive runs without significant loss in catalytic performance. In particular, due to the steric confinement effect of the inorganic backbone, the single different configuration among possible four stereo-isomers in aldol adducts were favorably obtained, respectively depending on the interaction between the o-, m- or p-position of nitrobenzaldehyde and the backbone, which was never observed in homogeneous aldol addition.

  3. Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures

    PubMed Central

    Orazov, Marat; Davis, Mark E.

    2015-01-01

    Retro-aldol reactions have been implicated as the limiting steps in catalytic routes to convert biomass-derived hexoses and pentoses into valuable C2, C3, and C4 products such as glycolic acid, lactic acid, 2-hydroxy-3-butenoic acid, 2,4-dihydroxybutanoic acid, and alkyl esters thereof. Due to a lack of efficient retro-aldol catalysts, most previous investigations of catalytic pathways involving these reactions were conducted at high temperatures (≥160 °C). Here, we report moderate-temperature (around 100 °C) retro-aldol reactions of various hexoses in aqueous and alcoholic media with catalysts traditionally known for their capacity to catalyze 1,2-intramolecular carbon shift (1,2-CS) reactions of aldoses, i.e., various molybdenum oxide and molybdate species, nickel(II) diamine complexes, alkali-exchanged stannosilicate molecular sieves, and amorphous TiO2–SiO2 coprecipitates. Solid Lewis acid cocatalysts that are known to catalyze 1,2-intramolecular hydride shift (1,2-HS) reactions that enable the formation of α-hydroxy carboxylic acids from tetroses, trioses, and glycolaldehyde, but cannot readily catalyze retro-aldol reactions of hexoses and pentoses at these moderate temperatures, are shown to be compatible with the aforementioned retro-aldol catalysts. The combination of a distinct retro-aldol catalyst with a 1,2-HS catalyst enables lactic acid and alkyl lactate formation from ketohexoses at moderate temperatures (around 100 °C), with yields comparable to best-reported chemocatalytic examples at high temperature conditions (≥160 °C). The use of moderate temperatures enables numerous desirable features such as lower pressure and significantly less catalyst deactivation. PMID:26372958

  4. Keeping condensers clean

    SciTech Connect

    Wicker, K.

    2006-04-15

    The humble condenser is among the biggest contributors to a steam power plant's efficiency. But although a clean condenser can provide great economic benefit, a dirty one can raise plant heat rate, resulting in large losses of generation revenue and/or unnecessarily high fuel bills. Conventional methods for cleaning fouled tubes range form chemicals to scrapers to brushes and hydro-blasters. This article compares the available options and describes how one power station, Omaha Public Power District's 600 MW North Omaha coal-fired power station, cleaned up its act. The makeup and cooling water of all its five units comes from the Missouri River. 6 figs.

  5. 21 CFR 573.200 - Condensed animal protein hydrolysate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Condensed animal protein hydrolysate. 573.200... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The...

  6. 21 CFR 573.200 - Condensed animal protein hydrolysate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Condensed animal protein hydrolysate. 573.200... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The...

  7. 21 CFR 573.200 - Condensed animal protein hydrolysate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Condensed animal protein hydrolysate. 573.200... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The...

  8. 21 CFR 573.200 - Condensed animal protein hydrolysate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Condensed animal protein hydrolysate. 573.200... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The...

  9. 16 CFR 1500.123 - Condensation of label information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Condensation of label information. 1500.123 Section 1500.123 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... Condensation of label information. Whenever the statement of the principal hazard or hazards itself...

  10. 16 CFR 1500.123 - Condensation of label information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Condensation of label information. 1500.123 Section 1500.123 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... Condensation of label information. Whenever the statement of the principal hazard or hazards itself...

  11. 16 CFR 1500.123 - Condensation of label information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Condensation of label information. 1500.123 Section 1500.123 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... Condensation of label information. Whenever the statement of the principal hazard or hazards itself...

  12. 16 CFR 1500.123 - Condensation of label information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Condensation of label information. 1500.123 Section 1500.123 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... Condensation of label information. Whenever the statement of the principal hazard or hazards itself...

  13. 16 CFR 1500.123 - Condensation of label information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Condensation of label information. 1500.123 Section 1500.123 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... Condensation of label information. Whenever the statement of the principal hazard or hazards itself...

  14. 21 CFR 573.200 - Condensed animal protein hydrolysate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Condensed animal protein hydrolysate. 573.200... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The...

  15. 40 CFR 65.151 - Condensers used as control devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... requirements. (1) Owners or operators using condensers to meet the 98 weight-percent emission reduction or 20 parts per million by volume outlet concentration requirements as specified in § 65.63(a)(2), or 40 CFR... providing a continuous record or a condenser exit (product side) temperature monitoring device capable...

  16. Simple Simulations of DNA Condensation

    SciTech Connect

    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.

  17. Detail of Bright Angel stone vault, containing condenser, Hoffman condensation ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of Bright Angel stone vault, containing condenser, Hoffman condensation pump, Jennings vacuum heating pump, and misc. pipes and valves. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  18. Condensate removal device

    DOEpatents

    Maddox, James W.; Berger, David D.

    1984-01-01

    A condensate removal device is disclosed which incorporates a strainer in unit with an orifice. The strainer is cylindrical with its longitudinal axis transverse to that of the vapor conduit in which it is mounted. The orifice is positioned inside the strainer proximate the end which is remoter from the vapor conduit.

  19. Inflation from gravitino condensates

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.

    2015-07-01

    We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry(supergravity), entirely independent of any coupling to external matter. The goldstino mode associated with the breaking of (global) supersymmetry is “eaten” by the gravitino field, which becomes massive (via its own vacuum condensation) and breaks supergravity dynamically. The most natural association of gravitino condensates with inflation proceeds in an indirect way, via a Starobinsky-type inflation, in the massive gravitino phase. This inflationary phase is associated with scalar modes hidden in the higher order curvature corrections of the effective action arising from integrating out massive gravitino degrees of freedom. The scenario is in agreement with Planck data phenomenology in a natural and phenomenologically-relevant range of parameters, namely Grand-Unified-Theory values for the supersymmetry breaking energy scale and dynamically-induced gravitino mass. A hill-top inflation, on the other hand, which could also occur in the model, whereby the role of the inflaton field is played by the gravitino condensate itself, would require significant fine tuning in the inflaton's wave function renormalisation and thus may be discarded on naturalness grounds.

  20. Drum drying performance of condensed distillers solubles and comparison to performance of modified condensed distillers solubles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Condensed distillers solubles (CDS) is a viscous, syrupy co-product of ethanol production from corn; CDS exhibits strong recalcitrance to drying due to its chemical composition, which includes a substantial amount of glycerol. The objectives of this study were to determine the drum drying performan...

  1. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    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

  2. Condensed Matter Nuclear Science

    NASA Astrophysics Data System (ADS)

    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

  3. Concise Enantioselective Synthesis of Oxygenated Steroids via Sequential Copper(II)-Catalyzed Michael Addition/Intramolecular Aldol Cyclization Reactions.

    PubMed

    Cichowicz, Nathan R; Kaplan, Will; Khomutnyk, Yaroslav; Bhattarai, Bijay; Sun, Zhankui; Nagorny, Pavel

    2015-11-18

    A new scalable enantioselective approach to functionalized oxygenated steroids is described. This strategy is based on chiral bis(oxazoline) copper(II) complex-catalyzed enantioselective and diastereoselective Michael reactions of cyclic ketoesters and enones to install vicinal quaternary and tertiary stereocenters. In addition, the utility of copper(II) salts as highly active catalysts for the Michael reactions of traditionally unreactive β,β'-enones and substituted β,β'-ketoesters that results in unprecedented Michael adducts containing vicinal all-carbon quaternary centers is also demonstrated. The Michael adducts subsequently undergo base-promoted diastereoselective aldol cascade reactions resulting in the natural or unnatural steroid skeletons. The experimental and computational studies suggest that the torsional strain effects arising from the presence of the Δ(5)-unsaturation are key controlling elements for the formation of the natural cardenolide scaffold. The described method enables expedient generation of polycyclic molecules including modified steroidal scaffolds as well as challenging-to-synthesize Hajos-Parrish and Wieland-Miescher ketones.

  4. Concise Enantioselective Synthesis of Oxygenated Steroids via Sequential Copper(II)-Catalyzed Michael Addition/Intramolecular Aldol Cyclization Reactions

    PubMed Central

    Cichowicz, Nathan R.; Kaplan, Will; Khomutnyk, Yaroslav; Bhattarai, Bijay; Sun, Zhankui; Nagorny, Pavel

    2015-01-01

    A new scalable enantioselective approach to functionalized oxygenated steroids is described. This strategy is based on chiral bis(oxazoline) copper(II) complex-catalyzed enantioselective and diastereoselective Michael reactions of cyclic ketoesters and enones to install vicinal quaternary and tertiary stereocenters. In addition, the utility of copper(II) salts as highly active catalysts for the Michael reactions of traditionally unreactive ββ′-enones and substituted ββ′-ketoesters that results in unprecedented Michael adducts containing vicinal all-carbon quaternary centers is also demonstrated. The Michael adducts subsequently undergo base-promoted diastereoselective aldol cascade reactions resulting in the natural or unnatural steroid skeletons. The experimental and computational studies suggest that the torsional strain effects arising from the presence of the Δ5-unsaturation are key controling elements for the formation of the natural cardenolide scaffold. The described method enables expedient generation of polycyclic molecules including modified steroidal scaffolds as well as challenging-to-synthesize Hajos-Parrish and Wieland-Miescher ketones. PMID:26491886

  5. Thermal decomposition of energetic materials: Temporal behaviors of the rates of formation of the gaseous pyrolysis products from condensed-phase decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

    SciTech Connect

    Behrens, R. Jr. )

    1990-08-23

    The temporal behaviors of the rates of formation of the gaseous products from the pyrolysis of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are determined by simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS). The gaseous products formed from the pyrolysis of HMX, and its deuterium- and {sup 15}NO{sub 2}-labeled analogues, between 210 and 235{degree}C are H{sub 2}O, HCN, CO, CH{sub 2}O, NO, N{sub 2}O, CH{sub 3}NHCHO, (CH{sub 3}){sub 2}NNO, 1-nitroso-3,5,7-trinitro-1,3,5,7-tetrazocine (ONTNTA), and their isotopic analogues. In addition, a nonvolatile residue (NVR) is formed. The NVR is a polyamide that decomposes between 250 and 780{degree}C producing NH{sub 3}, HCN, HNCO, H{sub 2}NCHO, CH{sub 3}NHCHO, and products that include long-chain hydrocarbons. The temporal behaviors of the rates of gas formation of the pyrolysis products along with the macroscopic and microscopic structure of the NVR indicate that complex physical processes and chemical mechanisms within the condensed phase of HMX control the decomposition.

  6. A highly productive, whole-cell DERA chemoenzymatic process for production of key lactonized side-chain intermediates in statin synthesis.

    PubMed

    Ošlaj, Matej; Cluzeau, Jérôme; Orkić, Damir; Kopitar, Gregor; Mrak, Peter; Casar, Zdenko

    2013-01-01

    Employing DERA (2-deoxyribose-5-phosphate aldolase), we developed the first whole-cell biotransformation process for production of chiral lactol intermediates useful for synthesis of optically pure super-statins such as rosuvastatin and pitavastatin. Herein, we report the development of a fed-batch, high-density fermentation with Escherichia coli BL21 (DE3) overexpressing the native E. coli deoC gene. High activity of this biomass allows direct utilization of the fermentation broth as a whole-cell DERA biocatalyst. We further show a highly productive bioconversion processes with this biocatalyst for conversion of 2-substituted acetaldehydes to the corresponding lactols. The process is evaluated in detail for conversion of acetyloxy-acetaldehyde with the first insight into the dynamics of reaction intermediates, side products and enzyme activity, allowing optimization of the feeding strategy of the aldehyde substrates for improved productivities, yields and purities. The resulting process for production of ((2S,4R)-4,6-dihydroxytetrahydro-2H-pyran-2-yl)methyl acetate (acetyloxymethylene-lactol) has a volumetric productivity exceeding 40 g L(-1) h(-1) (up to 50 g L(-1) h(-1)) with >80% yield and >80% chromatographic purity with titers reaching 100 g L(-1). Stereochemical selectivity of DERA allows excellent enantiomeric purities (ee >99.9%), which were demonstrated on downstream advanced intermediates. The presented process is highly cost effective and environmentally friendly. To our knowledge, this is the first asymmetric aldol condensation process achieved with whole-cell DERA catalysis and it simplifies and extends previously developed DERA-catalyzed approaches based on the isolated enzyme. Finally, applicability of the presented process is demonstrated by efficient preparation of a key lactol precursor, which fits directly into the lactone pathway to optically pure super-statins. PMID:23667462

  7. Photon condensation: A new paradigm for Bose-Einstein condensation

    NASA Astrophysics Data System (ADS)

    Rajan, Renju; Ramesh Babu, P.; Senthilnathan, K.

    2016-10-01

    Bose-Einstein condensation is a state of matter known to be responsible for peculiar properties exhibited by superfluid Helium-4 and superconductors. Bose-Einstein condensate (BEC) in its pure form is realizable with alkali atoms under ultra-cold temperatures. In this paper, we review the experimental scheme that demonstrates the atomic Bose-Einstein condensate. We also elaborate on the theoretical framework for atomic Bose-Einstein condensation, which includes statistical mechanics and the Gross-Pitaevskii equation. As an extension, we discuss Bose-Einstein condensation of photons realized in a fluorescent dye filled optical microcavity. We analyze this phenomenon based on the generalized Planck's law in statistical mechanics. Further, a comparison is made between photon condensate and laser. We describe how photon condensate may be a possible alternative for lasers since it does not require an energy consuming population inversion process.

  8. Gravity triggered neutrino condensates

    SciTech Connect

    Barenboim, Gabriela

    2010-11-01

    In this work we use the Schwinger-Dyson equations to study the possibility that an enhanced gravitational attraction triggers the formation of a right-handed neutrino condensate, inducing dynamical symmetry breaking and generating a Majorana mass for the right-handed neutrino at a scale appropriate for the seesaw mechanism. The composite field formed by the condensate phase could drive an early epoch of inflation. We find that to the lowest order, the theory does not allow dynamical symmetry breaking. Nevertheless, thanks to the large number of matter fields in the model, the suppression by additional powers in G of higher order terms can be compensated, boosting them up to their lowest order counterparts. This way chiral symmetry can be broken dynamically and the infrared mass generated turns out to be in the expected range for a successful seesaw scenario.

  9. Feshbach-Einstein Condensates

    SciTech Connect

    Rousseau, V. G.; Denteneer, P. J. H.

    2009-01-09

    We investigate the phase diagram of a two-species Bose-Hubbard model describing atoms and molecules on a lattice, interacting via a Feshbach resonance. We identify a region where the system exhibits an exotic super-Mott phase and regions with phases characterized by atomic and/or molecular condensates. Our approach is based on a recently developed exact quantum Monte Carlo algorithm: the stochastic Green function algorithm with tunable directionality. We confirm some of the results predicted by mean-field studies, but we also find disagreement with these studies. In particular, we find a phase with an atomic but no molecular condensate, which is missing in all mean-field phase diagrams.

  10. Multilayer graphene condenser microphone

    NASA Astrophysics Data System (ADS)

    Todorović, Dejan; Matković, Aleksandar; Milićević, Marijana; Jovanović, Djordje; Gajić, Radoš; Salom, Iva; Spasenović, Marko

    2015-12-01

    Vibrating membranes are the cornerstone of acoustic technology, forming the backbone of modern loudspeakers and microphones. Acoustic performance of a condenser microphone is derived mainly from the membrane’s size, surface mass and achievable static tension. The widely studied and available nickel has been a dominant membrane material for professional microphones for several decades. In this paper we introduce multilayer graphene as a membrane material for condenser microphones. The graphene device outperforms a high end commercial nickel-based microphone over a significant part of the audio spectrum, with a larger than 10 dB enhancement of sensitivity. Our experimental results are supported with numerical simulations, which also show that a 300 layer thick graphene membrane under maximum tension would offer excellent extension of the frequency range, up to 1 MHz.

  11. 40 CFR 405.90 - Applicability; description of the condensed milk subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... condensed milk subcategory. 405.90 Section 405.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.90 Applicability; description of the condensed milk subcategory. The provisions of...

  12. 40 CFR 405.90 - Applicability; description of the condensed milk subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... condensed milk subcategory. 405.90 Section 405.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.90 Applicability; description of the condensed milk subcategory. The provisions of...

  13. 40 CFR 405.90 - Applicability; description of the condensed milk subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... condensed milk subcategory. 405.90 Section 405.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.90 Applicability; description of the condensed milk subcategory. The provisions of...

  14. 40 CFR 405.90 - Applicability; description of the condensed milk subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... condensed milk subcategory. 405.90 Section 405.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.90 Applicability; description of the condensed milk subcategory. The provisions of...

  15. 40 CFR 405.90 - Applicability; description of the condensed milk subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... condensed milk subcategory. 405.90 Section 405.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.90 Applicability; description of the condensed milk subcategory. The provisions of...

  16. Bose-Einstein Condensation

    SciTech Connect

    El-Sherbini, Th.M.

    2005-03-17

    This article gives a brief review of Bose-Einstein condensation. It is an exotic quantum phenomenon that was observed in dilute atomic gases for the first time in 1995. It exhibits a new state of matter in which a group of atoms behaves as a single particle. Experiments on this form of matter are relevant to many different areas of physics- from atomic clocks and quantum computing to super fluidity, superconductivity and quantum phase transition.

  17. Asymmetric condensed dark matter

    NASA Astrophysics Data System (ADS)

    Aguirre, Anthony; Diez-Tejedor, Alberto

    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.

  18. Cooling and condensing of sulfur and water from claus process gas

    SciTech Connect

    Palm, J. W.; Kunkel, L. V.

    1985-07-02

    The Claus process gas is cooled in a condenser to condense most of the sulfur vapor in solid form. The gas leaving the condenser is then further cooled to condense water without producing substantially any sulfur in an undesirable form. The resulting gas of reduced water content is useful in Claus reaction, particularly the low temperature Claus reaction in which the product sulfur is adsorbed on the catalyst.

  19. Condensed phase conversion and growth of nanorods instead of from vapor

    DOEpatents

    Geohegan, David B.; Seals, Roland D.; Puretzky, Alex A.; Fan, Xudong

    2005-08-02

    Compositions, systems and methods are described for condensed phase conversion and growth of nanorods and other materials. A method includes providing a condensed phase matrix material; and activating the condensed phase matrix material to produce a plurality of nanorods by condensed phase conversion and growth from the condensed chase matrix material instead of from vacor. The compositions are very strong. The compositions and methods provide advantages because they allow (1) formation rates of nanostructures necessary for reasonable production rates, and (2) the near net shaped production of component structures.

  20. Condensed phase conversion and growth of nanorods and other materials instead of from vapor

    DOEpatents

    Geohegan, David B.; Seals, Roland D.; Puretzky, Alex A.; Fan, Xudong

    2010-10-19

    Compositions, systems and methods are described for condensed phase conversion and growth of nanorods and other materials. A method includes providing a condensed phase matrix material; and activating the condensed phase matrix material to produce a plurality of nanorods by condensed phase conversion and growth from the condensed phase matrix material instead of from vapor. The compositions are very strong. The compositions and methods provide advantages because they allow (1) formation rates of nanostructures necessary for reasonable production rates, and (2) the near net shaped production of component structures.

  1. Effect of spontaneous condensation on condensation heat transfer in the presence of non-condensable gases

    SciTech Connect

    Karl, J.; Hein, D.

    1999-07-01

    The presence of non condensable gases like nitrogen or air reduces the condensation heat transfer during condensation of binary steam mixtures. The non condensable gas accumulates in the vapor phase boundary layer and causes a high heat transfer resistance. Especially with high pressures and low water temperatures spontaneous condensation reduces heat transfer additionally. Fog forms within the steam-nitrogen boundary layer and the steam condenses on the water droplets of the fog layer. The convective mass transfer to the cooling water interface diminishes. Raman spectroscopy and film theory are used to quantify this effect locally. The calculation of overall condensation rates in large steam nitrogen systems requires to use three dimensional CFD codes. The paper presents equations to predict fog formation in the boundary layer which can be implemented in CFD codes.

  2. Advanced Condenser Boosts Geothermal Power Plant Output (Fact Sheet), The Spectrum of Clean Energy Innovation

    SciTech Connect

    Not Available

    2010-12-01

    When power production at The Geysers geothermal power complex began to falter, the National Renewable Energy Laboratory (NREL) stepped in, developing advanced condensing technology that dramatically boosted production efficiency - and making a major contribution to the effective use of geothermal power. NREL developed advanced direct-contact condenser (ADCC) technology to condense spent steam more effectively, improving power production efficiency in Unit 11 by 5%.

  3. Ti-direct, powerful, stereoselective aldol-type additions of esters and thioesters to carbonyl compounds: application to the synthesis and evaluation of lactone analogs of jasmone perfumes.

    PubMed

    Nagase, Ryohei; Matsumoto, Noriaki; Hosomi, Kohei; Higashi, Takahiro; Funakoshi, Syunsuke; Misaki, Tomonori; Tanabe, Yoo

    2007-01-01

    An efficient TiCl(4)-Et(3)N or Bu(3)N-promoted aldol-type addition of phenyl and thiophenyl esters or thioaryl esters with aldehydes and ketones was performed (total 46 examples). The present method is advantageous from atom-economical and cost-effective viewpoints; good to excellent yields, moderate to good syn-selectivity, substrate variations, reagent availability, and simple procedures. Utilizing the present reaction as the key step, an efficient short synthesis of three lactone [2(5H)-furanone] analogs of jasmine perfumes was performed. Among them, the lactone analog of cis-jasmone had a unique perfume property (tabac).

  4. Confinement Contains Condensates

    SciTech Connect

    Brodsky, Stanley J.; Roberts, Craig D.; Shrock, Robert; Tandy, Peter C.

    2012-03-12

    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 commonly been viewed as constant empirical mass-scales that fill all spacetime, are instead wholly contained within hadrons; i.e., they are a property of hadrons themselves and expressed, e.g., in their Bethe-Salpeter or light-front wave functions. We explain that this paradigm is consistent with empirical evidence, and incidentally expose misconceptions in a recent Comment.

  5. Condensed Plasmas under Microgravity

    NASA Technical Reports Server (NTRS)

    Morfill, G. E.; Thomas, H. M.; Konopka, U.; Rothermel, H.; Zuzic, M.; Ivlev, A.; Goree, J.; Rogers, Rick (Technical Monitor)

    1999-01-01

    Experiments under microgravity conditions were carried out to study 'condensed' (liquid and crystalline) states of a colloidal plasma (ions, electrons, and charged microspheres). Systems with approximately 10(exp 6) microspheres were produced. The observed systems represent new forms of matter--quasineutral, self-organized plasmas--the properties of which are largely unexplored. In contrast to laboratory measurements, the systems under microgravity are clearly three dimensional (as expected); they exhibit stable vortex flows, sometimes adjacent to crystalline regions, and a central 'void,' free of microspheres.

  6. Cloud Condensation in Titan's Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Romani, Paul N.; Anderson, Carrie M.

    2011-01-01

    A 1-D condensation model is developed for the purpose of reproducing ice clouds in Titan's lower stratosphere observed by the Composite Infrared Spectrometer (CIRS) onboard Cassini. Hydrogen cyanide (HCN), cyanoacetylene (HC3N), and ethane (C2H6) vapors are treated as chemically inert gas species that flow from an upper boundary at 500 km to a condensation sink near Titan's tropopause (-45 km). Gas vertical profiles are determined from eddy mixing and a downward flux at the upper boundary. The condensation sink is based upon diffusive growth of the cloud particles and is proportional to the degree of supersaturation in the cloud formation regIOn. Observations of the vapor phase abundances above the condensation levels and the locations and properties of the ice clouds provide constraints on the free parameters in the model. Vapor phase abundances are determined from CIRS mid-IR observations, whereas cloud particle sizes, altitudes, and latitudinal distributions are derived from analyses of CIRS far-IR observations of Titan. Specific cloud constraints include: I) mean particle radii of2-3 J.lm inferred from the V6 506 cm- band of HC3N, 2) latitudinal abundance distributions of condensed nitriles, inferred from a composite emission feature that peaks at 160/cm , and 3) a possible hydrocarbon cloud layer at high latitudes, located near an altitude of 60 km, which peaks between 60 and 80 cm l . Nitrile abundances appear to diminish substantially at high northern latitudes over the time period 2005 to 2010 (northern mid winter to early spring). Use of multiple gas species provides a consistency check on the eddy mixing coefficient profile. The flux at the upper boundary is the net column chemical production from the upper atmosphere and provides a constraint on chemical pathways leading to the production of these compounds. Comparison of the differing lifetimes, vapor phase transport, vapor phase loss rate, and particle sedimentation, sheds light on temporal stability

  7. An Exercise on Structure Elucidation Based on a Tricky Aldol Reaction

    ERIC Educational Resources Information Center

    Sierra, Manuel Gonzalez; Pellegrinet, Silvina C.; Colombo, Maria I.; Ruveda, Edmundo A.

    2008-01-01

    An exercise on structure elucidation for advanced undergraduate students is described. To determine the structure of an unknown product, students are required to use spectra together with an organic chemistry mechanism. This exercise exemplifies the procedure commonly used in research, thus helping students develop problem-solving skills. In…

  8. Quantitative assessment of DNA condensation.

    PubMed

    Trubetskoy, V S; Slattum, P M; Hagstrom, J E; Wolff, J A; Budker, V G

    1999-02-15

    A fluorescent method is proposed for assessing DNA condensation in aqueous solutions with variety of condensing agents. The technique is based on the effect of concentration-dependent self-quenching of covalently bound fluorophores upon DNA collapse. The method allows a more precise determination of charge equivalency in titration experiments with various polycations. The technique's ability to determine the number of DNA molecules that are condensed together in close proximity is under further investigation.

  9. Mitotic chromosome structure and condensation.

    PubMed

    Belmont, Andrew S

    2006-12-01

    Mitotic chromosome structure has been the cell biology equivalent of a 'riddle, wrapped in a mystery, inside an enigma'. Observations that genetic knockout or knockdown of condensin subunits or topoisomerase II cause only minimal perturbation in overall chromosome condensation, together with analysis of early stages of chromosome condensation and effects produced by histone H1 depletion, suggest a need to reconsider textbook models of mitotic chromosome condensation and organization. PMID:17046228

  10. Kaon Condensation with Lattice QCD

    SciTech Connect

    Detmold, Will; Detmold, William; Detmold, Will; Detmold, William; Savage, Martin; Walker-Loud, Andre; Orginos, Konstantinos; Torok, Aaron

    2008-09-01

    doi: http://dx.doi.org/10.1103/PhysRevD.78.054514
    Kaon condensation may play an important role in the structure of hadronic matter at densities greater than that of nuclear matter, as exist in the interior of neutron stars. We present the results of the first lattice QCD calculation of kaon condensation obtained by studying systems containing up to twelve charged kaons. Surprisingly, the equation of state of the condensate is remarkably well reproduced by leading order chiral perturbation theory. We determine the three-kaon interaction from the multi-kaon systems and update our results for pion condensates.

  11. Condensation Processes in Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Norman, D. I.; Moore, J. N.

    2005-12-01

    We model condensation processes in geothermal systems to understand how this process changes fluid chemistry. We assume two processes operate in geothermal systems: 1) condensation of a vapor phase derived by boiling an aqueous geothermal fluid into a cool near surface water and 2) condensation of a magmatic vapor by a deep circulating meteoric thermal fluid. It is assumed that the condensation process has two stages. Initially the condensing fluid is under saturated in gaseous species. Condensation of the vapor phase continues until the pressure on the fluid equals the sum of the partial pressures of water and the dissolved gaseous species. At that time bubbles flux through the condensing fluid. In time the fluid and fluxing gas phase come to equilibrium. Calculation shows that during the second stage of the condensation process the liquid phase becomes enriched in more soluble gaseous species like CO2 and H2S, and depleted in less soluble species like CH4 and N2. Stage 2 condensation processes can therefore be monitored by ratios of more and less condensable species like CO2/N2. Condensation of vapor released by boiling geothermal fluids results in liquids with high concentrations of H2S and CO2 like is seen in geothermal system steam-heated waters. Condensation of a magmatic vapor into circulating meteoric water has been proposed, but not well demonstrated. We compare to our models the Cerro Prieto, Mexico gas analysis data set collected over twelve years time by USGS personnel. It was assumed for modeling that the Cerro Prieto geothermal fluids are circulating meteoritic fluids with N2/Ar ratios about 40 to which is added a magmatic vapor with N2/Ar ratio = 400. The Cerro Prieto analyses show a strong correlation between N2/Ar and CO2/N2 as predicted by calculation. Two dimensional image plots of well N2/Ar + CO2/N2 show a bull's-eye pattern on the geothermal field. Image plots of analyses collected over a year or less time show N2/Ar and CO2/N2 hot spots

  12. Condenser for photolithography system

    SciTech Connect

    Sweatt, William C.

    2004-03-02

    A condenser for a photolithography system, in which a mask image from a mask is projected onto a wafer through a camera having an entrance pupil, includes a source of propagating radiation, a first mirror illuminated by the radiation, a mirror array illuminated by the radiation reflected from said first mirror, and a second mirror illuminated by the radiation reflected from the array. The mirror array includes a plurality of micromirrors. Each of the micromirrors is selectively actuatable independently of each other. The first mirror and the second mirror are disposed such that the source is imaged onto a plane of the mask and the mirror array is imaged into the entrance pupil of the camera.

  13. Microgravity condensing heat exchanger

    NASA Technical Reports Server (NTRS)

    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.

  14. Amine catalyzed condensation of tetraethylorthosilicate

    NASA Technical Reports Server (NTRS)

    Jones, S.

    2001-01-01

    The catalysis of the condensation of hydrolyzed metal alkoxides by amines has been mentioned in the literature, but there has been no systematic study of their influence on the rate of the condensation reaction of the alkoxide and the microstructure of the resultant gel.

  15. APPARATUS FOR CONDENSATION AND SUBLIMATION

    DOEpatents

    Schmidt, R.J.; Fuis, F. Jr.

    1958-10-01

    An apparatus is presented for the sublimation and condensation of uranium compounds in order to obtain an improved crystalline structure of this material. The apparatus comprises a vaporizing chamber and condensing structure connected thereto. There condenser is fitted with a removable liner having a demountable baffle attached to the liner by means of brackets and a removable pin. The baffle is of spiral cross-section and is provided with cooling coils disposed between the surfaces of the baffle for circulation of a temperature controlling liquid within the baffle. The cooling coll provides for controlllng the temperature of the baffle to insure formatlon of a satisfactory condensate, and the removable liner facilitates the removal of condensate formed during tbe sublimation process.

  16. The LICPA-driven collider—a novel efficient tool for the production of ultra-high pressures in condensed media

    NASA Astrophysics Data System (ADS)

    Badziak, J.; Krousky, E.; Kucharik, M.; Liska, R.

    2016-03-01

    Generation of strong shock waves for the production of Mbar or Gbar pressures is a topic of high relevance for contemporary research in various domains, including inertial confinement fusion, laboratory astrophysics, planetology and material science. The pressures in the multi-Mbar range can be produced by the shocks generated using chemical explosions, light-gas guns, Z-pinch machines or lasers. Higher pressures, in the sub-Gbar or Gbar range are attainable only with nuclear explosions or laser-based methods. Unfortunately, due to the low efficiency of energy conversion from a laser to the shock (below a few percent), multi-kJ, multi-beam lasers are needed to produce such pressures with these methods. Here, we propose and investigate a novel scheme for generating high-pressure shocks which is much more efficient than the laser-based schemes known so far. In the proposed scheme, the shock is generated in a dense target by the impact of a fast projectile driven by the laser-induced cavity pressure acceleration (LICPA) mechanism. Using two-dimensional hydrodynamic simulations and the measurements performed at the kilojoule PALS laser facility it is shown that in the LICPA-driven collider the laser-to-shock energy conversion efficiency can reach a very high value ~ 15-20 % and, as a result, the shock pressure ~ 0.5-1 Gbar can be produced using lasers of energy <= 0.5 kJ. On the other hand, the pressures in the multi-Mbar range could be produced in this collider with low-energy (~ 10 J) lasers available on the market. It would open up the possibility of conducting research in high energy-density science also in small, university-class laboratories.

  17. Experimental evidence for chair-like transition states in aldol reactions of methyl ketone lithium enolates: stereoselective synthesis and utilization of a deuterium-labeled enolate as a probe of reaction stereochemistry.

    PubMed

    Liu, Christopher M; Smith, William J; Gustin, Darin J; Roush, William R

    2005-04-27

    Aldol reactions of methyl ketone lithium enolates proceed via chairlike Zimmerman-Traxler transition states with 7:1 to 50:1 preference over alternative, boatlike transition structures, as determined by studies involving the configurationally stable deuterium-labeled enol silane 18 as the lithium enolate precursor.

  18. Maximize revenue from gas condensate wells

    SciTech Connect

    Hall, S.R.

    1988-07-01

    A computerized oil/gas modeling program called C.O.M.P. allows operators to select the economically optimum producing equipment for a given gas-condensate well-stream. This article, the first of two, discusses use of the model to analyze performance of six different production system on the same wellstream and at the same wellhead conditions. All producing equipment options are unattended wellhead facilities designed for high volume gas-condensate wells and are not gas plants. A second article to appear in September will discuss operating experience with one of the producing systems analyzed, integrated multi-stage separation with stabilization and compression (the HERO system), which was developed by U.S. Enertek, Inc. This equipment was chosen for the wellstream analyzed because of the potential revenue increase indicated by the model.

  19. Cosmic rays from cosmic strings with condensates

    SciTech Connect

    Vachaspati, Tanmay

    2010-02-15

    We revisit the production of cosmic rays by cusps on cosmic strings. If a scalar field ('Higgs') has a linear interaction with the string world sheet, such as would occur if there is a bosonic condensate on the string, cusps on string loops emit narrow beams of very high energy Higgses which then decay to give a flux of ultrahigh energy cosmic rays. The ultrahigh energy flux and the gamma to proton ratio agree with observations if the string scale is {approx}10{sup 13} GeV. The diffuse gamma ray and proton fluxes are well below current bounds. Strings that are lighter and have linear interactions with scalars produce an excess of direct and diffuse cosmic rays and are ruled out by observations, while heavier strings ({approx}10{sup 15} GeV) are constrained by their gravitational signatures. This leaves a narrow window of parameter space for the existence of cosmic strings with bosonic condensates.

  20. Water condensation: a multiscale phenomenon.

    PubMed

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

    2014-02-01

    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 the shortcomings of the thermodynamic theory in describing the nucleation and emphasize the importance of nanoscale effects. This leads to the description of condensation from a molecular viewpoint. Also presented is how the nucleation can be simulated by use of molecular models, and how the condensation process is simulated on the macroscale using computational fluid dynamics. Finally, examples of hybrid models combining molecular and macroscale models for the simulation of condensation on a surface are presented.

  1. Characterization of spacecraft humidity condensate

    NASA Technical Reports Server (NTRS)

    Muckle, Susan; Schultz, John R.; Sauer, Richard L.

    1994-01-01

    When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

  2. The evolutionary design of condensers

    NASA Astrophysics Data System (ADS)

    Bejan, A.; Lee, J.; Lorente, S.; Kim, Y.

    2015-03-01

    Condensers are flow architectures needed to provide high rates of condensation (or cooling) per unit volume, in enclosures with fixed volume. Their design has not changed from configurations consisting of the banks of horizontal tubes. In this paper, we outline a free path to evolving the design by exploring new features of flow configuration: flattened tubes, multiple tube sizes, arrays of flattened tubes, vertical tubes with turbulent film flow, forced convection condensation instead of gravity driven condensation, and the optimal length of a horizontal tube, i.e., the number of tubes in a column aligned with vapor cross flow. We show that the condensation density can be increased sizably by varying freely and without bias the morphology of the flow system: the shapes and arrangement of the cooled surfaces on which condensation occurs. The evolution of technology is described in terms of the special time direction of the useful (purposeful) changes in the configuration (shapes, arrangements) of surfaces on which flow/condensation occurs. This explains what "evolution" means. It is an important step for physics, not just technology.

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

    SciTech Connect

    Not Available

    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).

  4. Baryonic condensates on the conifold

    NASA Astrophysics Data System (ADS)

    Benna, Marcus K.; Dymarsky, Anatoly; Klebanov, Igor R.

    2007-08-01

    We provide new evidence for the gauge/string duality between the baryonic branch of the cascading SU(k(M+1)) × SU(kM) gauge theory and a family of type IIB flux backgrounds based on warped products of the deformed conifold and Bbb R3,1. We show that a Euclidean D5-brane wrapping all six deformed conifold directions can be used to measure the baryon expectation values, and present arguments based on κ-symmetry and the equations of motion that identify the gauge bundles required to ensure worldvolume supersymmetry of this object. Furthermore, we investigate its coupling to the pseudoscalar and scalar modes associated with the phase and magnitude, respectively, of the baryon expectation value. We find that these massless modes perturb the Dirac-Born-Infeld and Chern-Simons terms of the D5-brane action in a way consistent with our identification of the baryonic condensates. We match the scaling dimension of the baryon operators computed from the D5-brane action with that found in the cascading gauge theory. We also derive and numerically evaluate an expression that describes the variation of the baryon expectation values along the supergravity dual of the baryonic branch.

  5. Coulomb interactions and fermion condensation

    SciTech Connect

    Capstick, S.; Cutkosky, R.E.; Joensen, M.A. ); Wang, K.C. )

    1990-08-15

    The influence of the Coulomb interaction in states containing massless and flavorless fermion-antifermion pairs is studied, using a continuum formulation within the finite volume {ital S}{sup 3}. Several different forms for the Coulomb interaction are examined, including confining potentials as well as nonconfining potentials. The calculations show that if the interaction is strong enough, the Coulomb interaction leads to condensation of pairs, and that this condensation has a chiral character. The condensation does not depend on whether the interaction is confining. It is found that simplified variational approximations are not accurate enough for an adequate description of the states.

  6. Neonatal hygroscopic condenser humidifier.

    PubMed

    Gedeon, A; Mebius, C; Palmer, K

    1987-01-01

    A hygroscopic condenser humidifier was developed for neonates on mechanical ventilation and was evaluated by laboratory tests and clinically. Humidification provided by the unit was measured in the 10- to 50-ml tidal-volume range at ambient temperatures of 24 degrees C and 38 degrees C. The effect of a leaking patient connection on device performance was investigated. Leakage rates were measured routinely in a neonatal ICU and surgery to determine the clinical significance. In the entire tidal volume and temperature range, the unit provided an inspiratory water content in excess of 30 g/m3 when the leak fraction (volume leaked/volume delivered at Y-piece) was less than 15%. This was found in three out of four cases. In about one out of ten cases, the leak exceeded 30%, which invariably led to corrective action, such as repositioning or changing the endotracheal tube. However, even at a 30% leak, a water content of about 26 g/m3 was still available for humidifying the inspired gas, which corresponds to normal physiologic conditions found in the trachea for nasal breathing of room air.

  7. Thermalization of gluons with Bose-Einstein condensation.

    PubMed

    Xu, Zhe; Zhou, Kai; Zhuang, Pengfei; Greiner, Carsten

    2015-05-01

    We study the thermalization of gluons far from thermal equilibrium in relativistic kinetic theory. The initial distribution of gluons is assumed to resemble that in the early stage of ultrarelativistic heavy ion collisions. Only elastic scatterings in static, nonexpanding gluonic matter are considered. At first we show that the occurrence of condensation in the limit of vanishing particle mass requires a general constraint for the scattering matrix element. Then the thermalization of gluons with Bose-Einstein condensation is demonstrated in a transport calculation. We see a continuously increasing overpopulation of low energy gluons, followed by a decrease to the equilibrium distribution, when the condensation occurs. The times of the completion of the gluon condensation and of the entropy production are calculated. These times scale inversely with the energy density.

  8. Molecular fossils in Cretaceous condensate from western India

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sharmila; Dutta, Suryendu; Dutta, Ratul

    2014-06-01

    The present study reports the biomarker distribution of condensate belonging to the early Cretaceous time frame using gas chromatography-mass spectrometry (GC-MS). The early Cretaceous palaeoenvironment was inscribed into these molecular fossils which reflected the source and conditions of deposition of the condensate. The saturate fraction of the condensate is characterized by normal alkanes ranging from n-C9 to n-C29 (CPI-1.13), cycloalkanes and C14 and C15 sesquiterpanes. The aromatic fraction comprises of naphthalene, phenanthrene, their methylated derivatives and cyclohexylbenzenes. Isohexylalkylnaphthalenes, a product of rearrangement process of terpenoids, is detected in the condensate. Several aromatic sesquiterpenoids and diterpenoids have been recorded. Dihydro- ar-curcumene, cadalene and ionene form the assemblage of sesquiterpenoids which are indicative of higher plant input. Aromatic diterpenoid fraction comprises of simonellite and retene. These compounds are also indicative of higher plants, particularly conifer source which had been a predominant flora during the Cretaceous time.

  9. Using condenser performance measurements to optimize condenser cleaning

    SciTech Connect

    Wolff, P.J.; March, A.; Pearson, H.S.

    1996-05-01

    Because plant personnel perform condenser monitoring primarily to determine cleaning schedules, the accuracy and repeatability of a technique should be viewed within the context of a condenser cleaning schedule. Lower accuracy is acceptable if the cleaning schedule arising from that system is identical to a cleaning schedule arising from a technique with higher accuracy. Three condenser performance monitors were implemented and compared within the context of a condenser cleaning schedule to determine the relative advantages of different condenser monitoring techniques. These systems include a novel on-line system that consists of an electromagnetic flowmeter and an RTD mounted in a compact waterproof cylinder, an overall on-line system, and routine plant tests. The fouling measurements from each system are used in an optimization program which automatically computes a cleaning schedule that minitrack the combined cost of cleaning and the cost of increased fuel consumption caused by condenser fouling. The cleaning schedules resulting from each system`s measurements are compared. The optimization routine is also used to evaluate the sensitivity of optimal cleaning schedules to fouling rate and of the cost in dollars for non-optimal cleaning.

  10. Decoherence effects in Bose-Einstein condensate interferometry I. General theory

    SciTech Connect

    Dalton, B.J.

    2011-03-15

    Research Highlights: > Theory of dephasing, decoherence effects for Bose-Einstein condensate interferometry. > Applies to single component, two mode condensate in double potential well. > Phase space theory using Wigner, positive P representations for condensate, non-condensate fields. > Stochastic condensate, non-condensate field equations and properties of noise fields derived. > Based on mean field theory with condensate modes given by generalised Gross-Pitaevskii equations. - Abstract: The present paper outlines a basic theoretical treatment of decoherence and dephasing effects in interferometry based on single component Bose-Einstein condensates in double potential wells, where two condensate modes may be involved. Results for both two mode condensates and the simpler single mode condensate case are presented. The approach involves a hybrid phase space distribution functional method where the condensate modes are described via a truncated Wigner representation, whilst the basically unoccupied non-condensate modes are described via a positive P representation. The Hamiltonian for the system is described in terms of quantum field operators for the condensate and non-condensate modes. The functional Fokker-Planck equation for the double phase space distribution functional is derived. Equivalent Ito stochastic equations for the condensate and non-condensate fields that replace the field operators are obtained, and stochastic averages of products of these fields give the quantum correlation functions that can be used to interpret interferometry experiments. The stochastic field equations are the sum of a deterministic term obtained from the drift vector in the functional Fokker-Planck equation, and a noise field whose stochastic properties are determined from the diffusion matrix in the functional Fokker-Planck equation. The stochastic properties of the noise field terms are similar to those for Gaussian-Markov processes in that the stochastic averages of odd

  11. 21 CFR 573.450 - Fermented ammoniated condensed whey.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Specifications. The product contains 35 to 55 percent crude protein and not more than 42 percent equivalent crude protein from nonprotein nitrogen sources. (c) Uses. The product is used as a source of protein and... use of fermented ammoniated condensed whey and equivalent crude protein from all other added forms...

  12. 21 CFR 573.450 - Fermented ammoniated condensed whey.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Specifications. The product contains 35 to 55 percent crude protein and not more than 42 percent equivalent crude protein from nonprotein nitrogen sources. (c) Uses. The product is used as a source of protein and... use of fermented ammoniated condensed whey and equivalent crude protein from all other added forms...

  13. 21 CFR 573.450 - Fermented ammoniated condensed whey.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Specifications. The product contains 35 to 55 percent crude protein and not more than 42 percent equivalent crude protein from nonprotein nitrogen sources. (c) Uses. The product is used as a source of protein and... use of fermented ammoniated condensed whey and equivalent crude protein from all other added forms...

  14. Hierarchical condensation near phase equilibrium

    NASA Astrophysics Data System (ADS)

    Olemskoi, A. I.; Yushchenko, O. V.; Borisyuk, V. N.; Zhilenko, T. I.; Kosminska, Yu. O.; Perekrestov, V. I.

    2012-06-01

    A novel mechanism of new phase formation is studied both experimentally and theoretically in the example of quasi-equilibrium stationary condensation in an ion-plasma sputterer. Copper condensates are obtained to demonstrate that a specific network structure is formed as a result of self-assembly in the course of deposition. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. The Langevin equation and the Fokker-Planck equation related are found to describe stationary distribution of thermodynamic potential variations at condensation. Time dependence of the formation probability of branching structures is found to clarify the experimental situation.

  15. Nonequilibrium thermodynamics of wealth condensation

    NASA Astrophysics Data System (ADS)

    Braun, Dieter

    2006-09-01

    We analyze wealth condensation for a wide class of stochastic economy models on the basis of the economic analog of thermodynamic potentials, termed transfer potentials. The economy model is based on three common transfers modes of wealth: random transfer, profit proportional to wealth and motivation of poor agents to work harder. The economies never reach steady state. Wealth condensation is the result of stochastic tunneling through a metastable transfer potential. In accordance with reality, both wealth and income distribution transiently show Pareto tails for high-income subjects. For metastable transfer potentials, exponential wealth condensation is a robust feature. For example with 10% annual profit 1% of the population owns 50% of the wealth after 50 years. The time to reach such a strong wealth condensation is a hyperbolic function of the annual profit rate.

  16. Flow Boiling and Condensation Experiment

    NASA Video Gallery

    The Flow Boiling and Condensation Experiment is another investigation that examines the flow of a mixture of liquids and the vapors they produce when in contact with hot space system equipment. Coo...

  17. Synthesis, double-helix formation, and higher-assembly formation of chiral polycyclic aromatic compounds: conceptual development of polyketide aldol synthesis.

    PubMed

    Yamaguchi, Masahiko; Shigeno, Masanori; Saito, Nozomi; Yamamoto, Koji

    2014-02-01

    Polycyclic aromatic compounds are an important group of substances in chemistry, and the study of their properties is a subject of interest in the development of drugs and materials. We have been conducting studies to develop chiral polycyclic aromatic compounds, i.e., helicenes and equatorenes. These helical molecules showed notable aggregate-forming properties and the capability for chiral recognition exerted by noncovalent bond interactions, which were not observed in compounds with central chirality. Homo- and hetero-double-helix-forming helicene oligomers were developed, and the latter self-assembled to form gels and vesicles. In this article, we describe such hierarchical studies of polycyclic aromatic compounds, which were started from polyketide aldol synthesis.

  18. Rapid Drop Dynamics During Superhydrophobic Condensation

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaodong; Boreyko, Jonathan; Chen, Chuan-Hua

    2008-11-01

    Rapid drop motion is observed on superhydrophobic surfaces during condensation; condensate drops with diameter of order 10 μm can move at above 100G and 0.1 m/s. When water vapor condenses on a horizontal superhydrophobic surface, condensate drops move in a seemingly random direction. The observed motion is attributed to the energy released through coalescence of neighboring condensate drops. A scaling analysis captured the initial acceleration and terminal velocity. Our work is a step forward in understanding the dynamics of superhydrophobic condensation occurring in both natural water-repellant plants and engineered dropwise condensers.

  19. Development of a Market Optimized Condensing Gas Water Heater

    SciTech Connect

    Peter Pescatore

    2006-01-11

    This program covered the development of a market optimized condensing gas water heater for residential applications. The intent of the program was to develop a condensing design that minimized the large initial cost premium associated with traditional condensing water heater designs. Equally important was that the considered approach utilizes design and construction methods that deliver the desired efficiency without compromising product reliability. Standard condensing water heater approaches in the marketplace utilize high cost materials such as stainless steel tanks and heat exchangers as well as expensive burner systems to achieve the higher efficiencies. The key in this program was to develop a water heater design that uses low-cost, available components and technologies to achieve higher efficiency at a modest cost premium. By doing this, the design can reduce the payback to a more reasonable length, increasing the appeal of the product to the marketplace. Condensing water heaters have been in existence for years, but have not been able to significantly penetrate the market. The issue has typically been cost. The high purchase price associated with existing condensing water heaters, sometimes as much as $2000, has been a very difficult hurdle to overcome in the marketplace. The design developed under this program has the potential to reduce the purchase price of this condensing design by as much as $1000 as compared to traditional condensing units. The condensing water heater design developed over the course of this program led to an approach that delivered the following performance attributes: 90%+ thermal efficiency; 76,000 Btu/hr input rate in a 50 gallon tank; First hour rating greater than 180 gph; Rapid recovery time; and Overall operating condition well matched to combination heat and hot water applications. Over the final three years of the program, TIAX worked very closely with A.O. Smith Water Products Company as our commercial partner to optimize

  20. Bose-Einstein condensation on a microelectronic chip.

    PubMed

    Hänsel, W; Hommelhoff, P; Hänsch, T W; Reichel, J

    2001-10-01

    Although Bose-Einstein condensates of ultracold atoms have been experimentally realizable for several years, their formation and manipulation still impose considerable technical challenges. An all-optical technique that enables faster production of Bose-Einstein condensates was recently reported. Here we demonstrate that the formation of a condensate can be greatly simplified using a microscopic magnetic trap on a chip. We achieve Bose-Einstein condensation inside the single vapour cell of a magneto-optical trap in as little as 700 ms-more than a factor of ten faster than typical experiments, and a factor of three faster than the all-optical technique. A coherent matter wave is emitted normal to the chip surface when the trapped atoms are released into free fall; alternatively, we couple the condensate into an 'atomic conveyor belt', which is used to transport the condensed cloud non-destructively over a macroscopic distance parallel to the chip surface. The possibility of manipulating laser-like coherent matter waves with such an integrated atom-optical system holds promise for applications in interferometry, holography, microscopy, atom lithography and quantum information processing.

  1. Bose-Einstein condensation on a microelectronic chip

    NASA Astrophysics Data System (ADS)

    Hänsel, W.; Hommelhoff, P.; Hänsch, T. W.; Reichel, J.

    2001-10-01

    Although Bose-Einstein condensates of ultracold atoms have been experimentally realizable for several years, their formation and manipulation still impose considerable technical challenges. An all-optical technique that enables faster production of Bose-Einstein condensates was recently reported. Here we demonstrate that the formation of a condensate can be greatly simplified using a microscopic magnetic trap on a chip. We achieve Bose-Einstein condensation inside the single vapour cell of a magneto-optical trap in as little as 700ms-more than a factor of ten faster than typical experiments, and a factor of three faster than the all-optical technique. A coherent matter wave is emitted normal to the chip surface when the trapped atoms are released into free fall; alternatively, we couple the condensate into an `atomic conveyor belt', which is used to transport the condensed cloud non-destructively over a macroscopic distance parallel to the chip surface. The possibility of manipulating laser-like coherent matter waves with such an integrated atom-optical system holds promise for applications in interferometry, holography, microscopy, atom lithography and quantum information processing.

  2. Dicarboxylic acid anhydride condensation with compounds containing active methylene groups. 4: Some 4-nitrophthalic anhydride condensation reactions

    NASA Technical Reports Server (NTRS)

    Oskaja, V.; Rotberg, J.

    1985-01-01

    By 4-nitrophthalic anhydride condensation with acetoacetate in acetic anhydride and triethylamine solution with subsequent breakdown of the intermediate condensation product, 5-nitroindanedione-1,3 was obtained. A 4-nitrophthalic anhydride with acetic anhydride, according to reaction conditions, may yield two products: in the presence of potassium acetate and at high temperatures 4-(or 5-)-nitro-2-acetylbenzoic acid is formed: in the presence of triethylamine and at room temperature 5-( or 6-)-nitrophthalic acetic acid is isolated. A 4-nitrophthalic anhydride and malonic acid in pyridine solution according to temperature yield either 5-( or 6-)-nitrophthalic acetic acid or 4-(or 5-)-nitro-2-acetylbenzoic acid.

  3. Polariton condensates at room temperature

    NASA Astrophysics Data System (ADS)

    Guillet, Thierry; Brimont, Christelle

    2016-10-01

    We review the recent developments of the polariton physics in microcavities featuring the exciton-photon strong coupling at room temperature, and leading to the achievement of room-temperature polariton condensates. Such cavities embed active layers with robust excitons that present a large binding energy and a large oscillator strength, i.e. wide bandgap inorganic or organic semiconductors, or organic molecules. These various systems are compared, in terms of figures of merit and of common features related to their strong oscillator strength. The various demonstrations of polariton laser are compared, as well as their condensation phase diagrams. The room-temperature operation indeed allows a detailed investigation of the thermodynamic and out-of-equilibrium regimes of the condensation process. The crucial role of the spatial dynamics of the condensate formation is discussed, as well as the debated issue of the mechanism of stimulated relaxation from the reservoir to the condensate under non-resonant excitation. Finally the prospects of polariton devices are presented.

  4. Condensation modes in magnetized plasmas

    NASA Technical Reports Server (NTRS)

    An, Chang-Hyuk

    1986-01-01

    Condensation modes in magnetized cylindrical plasmas, with concentration on how magnetic field affects the stability were studied. It is found that the effects of magnetic field (shear, twist, and strength) on the condensation modes are different depending on the wave vector. For modes whose wave vector is not perpendicular to magnetic field lines the plasma motion is mainly along the field lines; the effects of magnetic field on the modes are negligible except on the heat flow parallel to the field line. For a mode which is localized near a surface where the wave vector is perpendicular to the field line, the plasma moves perpendicular to the line carrying the field line into the condensed region; magnetic field affects the mode by building up magnetic pressure in the condensed region. The stability of condensation modes strongly depends on how density and temperature vary with field twist. The stable nature of global quiescent prominence magnetic configurations implies that prominences form for low field twist for which ideal MHD modes are stable; plasma temperature should increase with field twist for stable prominence formation.

  5. Acrolein sequestering ability of the endogenous tripeptide glycyl-histidyl-lysine (GHK): characterization of conjugation products by ESI-MSn and theoretical calculations.

    PubMed

    Beretta, Giangiacomo; Arlandini, Emanuele; Artali, Roberto; Anton, Josep M Garcia; Maffei Facino, R

    2008-07-15

    Acrolein (ACR) is a well-known carbonyl toxin produced by lipid peroxidation of polyunsaturated fatty acids, which is involved in several life-threatening pathologies such as Alzheimer disease, arteriosclerosis, diabetes, and nephropathy. The aim of this work was to study the quenching ability of the endogenous tripeptide glycyl-histidyl-lysine (GHK), a liver cell growth factor isolated from human plasma, towards the electrophilic aldehyde ACR and to characterize the reaction products by electrospray mass spectrometry (ESI-MS/MS infusion experiments; positive ion mode). The reaction of ACR (30 microM) with GHK (0.1, 0.25, 0.5, 1.0 mM) was followed by measuring aldehyde consumption by reverse-phase HPLC (phosphate buffer, pH 7.4); after 4h, when the aldehyde had completely disappeared; the reaction products were checked by ESI-MS/MS. Several products were detected in the GHK+ACR reaction (1:1). This indicates a complex reaction cascade involving the sequential addition of ACR (up to 3 mol) to the tripeptide GHK and, in particular, to the epsilon-amino group of the lysine residue and to the N(tau) and N(pi) of the histidine moiety. The Michael addition of two molecules of ACR to the epsilon-amino group of the lysine residue is followed by aldol condensation and dehydration to give the N-(3-formyl-3,4-dehydropiperidino) derivative. The results confirm that the ESI-MS/MS approach in a direct infusion experiment permits rapid profiling of the products of the GHK+ACR reaction. They firstly point to the potential medicinal use of GHK in the prevention of carbonyl stress-linked pathologies, and--second--help shed light on the physiological role of this histidine-containing tripeptide which is claimed to be an endogenous growth factor, but has never been shown to be an ACR quencher. PMID:18378108

  6. On the onset of surface condensation: formation and transition mechanisms of condensation mode

    PubMed Central

    Sheng, Qiang; Sun, Jie; Wang, Qian; Wang, Wen; Wang, Hua Sheng

    2016-01-01

    Molecular dynamics simulations have been carried out to investigate the onset of surface condensation. On surfaces with different wettability, we snapshot different condensation modes (no-condensation, dropwise condensation and filmwise condensation) and quantitatively analyze their characteristics by temporal profiles of surface clusters. Two different types of formation of nanoscale droplets are identified, i.e. the formations with and without film-like condensate. We exhibit the effect of surface tensions on the formations of nanoscale droplets and film. We reveal the formation mechanisms of different condensation modes at nanoscale based on our simulation results and classical nucleation theory, which supplements the ‘classical hypotheses’ of the onset of dropwise condensation. We also reveal the transition mechanism between different condensation modes based on the competition between surface tensions and reveal that dropwise condensation represents the transition states from no-condensation to filmwise condensation. PMID:27481071

  7. On the onset of surface condensation: formation and transition mechanisms of condensation mode

    NASA Astrophysics Data System (ADS)

    Sheng, Qiang; Sun, Jie; Wang, Qian; Wang, Wen; Wang, Hua Sheng

    2016-08-01

    Molecular dynamics simulations have been carried out to investigate the onset of surface condensation. On surfaces with different wettability, we snapshot different condensation modes (no-condensation, dropwise condensation and filmwise condensation) and quantitatively analyze their characteristics by temporal profiles of surface clusters. Two different types of formation of nanoscale droplets are identified, i.e. the formations with and without film-like condensate. We exhibit the effect of surface tensions on the formations of nanoscale droplets and film. We reveal the formation mechanisms of different condensation modes at nanoscale based on our simulation results and classical nucleation theory, which supplements the ‘classical hypotheses’ of the onset of dropwise condensation. We also reveal the transition mechanism between different condensation modes based on the competition between surface tensions and reveal that dropwise condensation represents the transition states from no-condensation to filmwise condensation.

  8. On the onset of surface condensation: formation and transition mechanisms of condensation mode.

    PubMed

    Sheng, Qiang; Sun, Jie; Wang, Qian; Wang, Wen; Wang, Hua Sheng

    2016-08-02

    Molecular dynamics simulations have been carried out to investigate the onset of surface condensation. On surfaces with different wettability, we snapshot different condensation modes (no-condensation, dropwise condensation and filmwise condensation) and quantitatively analyze their characteristics by temporal profiles of surface clusters. Two different types of formation of nanoscale droplets are identified, i.e. the formations with and without film-like condensate. We exhibit the effect of surface tensions on the formations of nanoscale droplets and film. We reveal the formation mechanisms of different condensation modes at nanoscale based on our simulation results and classical nucleation theory, which supplements the 'classical hypotheses' of the onset of dropwise condensation. We also reveal the transition mechanism between different condensation modes based on the competition between surface tensions and reveal that dropwise condensation represents the transition states from no-condensation to filmwise condensation.

  9. On the onset of surface condensation: formation and transition mechanisms of condensation mode.

    PubMed

    Sheng, Qiang; Sun, Jie; Wang, Qian; Wang, Wen; Wang, Hua Sheng

    2016-01-01

    Molecular dynamics simulations have been carried out to investigate the onset of surface condensation. On surfaces with different wettability, we snapshot different condensation modes (no-condensation, dropwise condensation and filmwise condensation) and quantitatively analyze their characteristics by temporal profiles of surface clusters. Two different types of formation of nanoscale droplets are identified, i.e. the formations with and without film-like condensate. We exhibit the effect of surface tensions on the formations of nanoscale droplets and film. We reveal the formation mechanisms of different condensation modes at nanoscale based on our simulation results and classical nucleation theory, which supplements the 'classical hypotheses' of the onset of dropwise condensation. We also reveal the transition mechanism between different condensation modes based on the competition between surface tensions and reveal that dropwise condensation represents the transition states from no-condensation to filmwise condensation. PMID:27481071

  10. Spacecraft Crew Cabin Condensation Control

    NASA Technical Reports Server (NTRS)

    Carrillo, Laurie Y.; Rickman, Steven L.; Ungar, Eugene K.

    2013-01-01

    A report discusses a new technique to prevent condensation on the cabin walls of manned spacecraft exposed to the cold environment of space, as such condensation could lead to free water in the cabin. This could facilitate the growth of mold and bacteria, and could lead to oxidation and weakening of the cabin wall. This condensation control technique employs a passive method that uses spacecraft waste heat as the primary wallheating mechanism. A network of heat pipes is bonded to the crew cabin pressure vessel, as well as the pipes to each other, in order to provide for efficient heat transfer to the cabin walls and from one heat pipe to another. When properly sized, the heat-pipe network can maintain the crew cabin walls at a nearly uniform temperature. It can also accept and distribute spacecraft waste heat to maintain the pressure vessel above dew point.

  11. Condensed hydrogen for thermonuclear fusion

    SciTech Connect

    Kucheyev, S. O.; Hamza, A. V.

    2010-11-15

    Inertial confinement fusion (ICF) power, in either pure fusion or fission-fusion hybrid reactors, is a possible solution for future world's energy demands. Formation of uniform layers of a condensed hydrogen fuel in ICF targets has been a long standing materials physics challenge. Here, we review the progress in this field. After a brief discussion of the major ICF target designs and the basic properties of condensed hydrogens, we review both liquid and solid layering methods, physical mechanisms causing layer nonuniformity, growth of hydrogen single crystals, attempts to prepare amorphous and nanostructured hydrogens, and mechanical deformation behavior. Emphasis is given to current challenges defining future research areas in the field of condensed hydrogens for fusion energy applications.

  12. Introduction. Cosmology meets condensed matter.

    PubMed

    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.

  13. Gravity Effects in Condensing and Evaporating Films

    NASA Technical Reports Server (NTRS)

    Hermanson, J. C.; Som, S. M.; Allen, J. S.; Pedersen, P. C.

    2004-01-01

    A general overview of gravity effects in condensing and evaporating films is presented. The topics include: 1) Research Overview; 2) NASA Recognizes Critical Need for Condensation & Evaporation Research to Enable Human Exploration of Space; 3) Condensation and Evaporation Research in Reduced Gravity is Enabling for AHST Technology Needs; 4) Differing Role of Surface Tension on Condensing/Evaporating Film Stability; 5) Fluid Mechanisms in Condensing and Evaporating Films in Reduced Gravity; 6) Research Plan; 7) Experimental Configurations for Condensing Films; 8) Laboratory Condensation Test Cell; 9) Aircraft Experiment; 10) Condensation Study Current Test Conditions; 11) Diagnostics; 12) Shadowgraph Images of Condensing n- pentane Film in Unstable (-1g) Configuration; 13) Condensing n-Pentane Film in Normal Gravity (-1g) at Constant Pressure; 14) Condensing n-Pentane Film in Normal Gravity (-1g) with Cyclic Pressure; 15) Non-condensing Pumped Film in Normal Gravity (-1g); 16) Heat Transfer Coefficient in Developing, Unstable Condensing Film in Normal Gravity; 17) Heat Transfer for Unsteady Condensing Film (-1g); 18) Ultrasound Measurement of Film Thickness N-pentane Film, Stable (+1g) Configuration; and 19) Ultrasound Measurement of Film Thickness N-pentane Film, Unstable (-1g) Configuration.

  14. 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.

    PubMed

    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.

  15. Turbulent mixing condensation nucleus counter

    NASA Astrophysics Data System (ADS)

    Mavliev, Rashid

    The construction and operating principles of the Turbulent Mixing Condensation Nucleus Counter (TM CNC) are described. Estimations based on the semiempirical theory of turbulent jets and the classical theory of nucleation and growth show the possibility of detecting particles as small as 2.5 nm without the interference of homogeneous nucleation. This conclusion was confirmed experimentally during the International Workshop on Intercomparison of Condensation Nuclei and Aerosol Particle Counters (Vienna, Austria). Number concentration, measured by the Turbulent Mixing CNC and other participating instruments, is found to be essentially equal.

  16. Condensation in Titan's lower atmosphere

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Griffith, C. A.; Yelle, R. V.

    2011-10-01

    We present a self-consistent description of Titan's aerosols-clouds-gases system and compare our results with the optical properties retrieved from measurements made by the Descent Imager / Spectral Radiometer (DISR) experiment on the Huygens probe [4]. Our calculations include the condensation of methane, ethane and hydrogen cyanide on photochemical aerosols produced in the thermosphere. Our results suggest that the two distinct extinction layers observed by DISR below 80 km are produced by HCN and methane condensation, respectively, while for the Huygens' equatorial conditions simulated here, the contribution of ethane clouds to the total opacity is negligible

  17. Adiabatic preparation of Floquet condensates

    NASA Astrophysics Data System (ADS)

    Heinisch, Christoph; Holthaus, Martin

    2016-10-01

    We argue that a Bose-Einstein condensate can be transformed into a Floquet condensate, that is, into a periodically time-dependent many-particle state possessing the coherence properties of a mesoscopically occupied single-particle Floquet state. Our reasoning is based on the observation that the denseness of the many-body system's quasienergy spectrum does not necessarily obstruct effectively adiabatic transport. Employing the idealized model of a driven bosonic Josephson junction, we demonstrate that only a small amount of Floquet entropy is generated when a driving force with judiciously chosen frequency and maximum amplitude is turned on smoothly.

  18. Enantio- and Diastereoselective Synthesis of syn-β-Hydroxy-α-Vinyl Carboxylic Esters via Reductive Aldol Reactions of Ethyl Allenecarboxylate with 10-TMS-9-Borabicyclo[3.3.2]decane and DFT Analysis of the Hydroboration Pathway

    PubMed Central

    Kister, Jeremy; Ess, Daniel H.

    2013-01-01

    An enantio- and diastereoselective synthesis of syn-β-hydroxy-α-vinyl carboxylate esters 3 via the reductive aldol reaction of ethyl allenecarboxylate (2) with 10-trimethylsilyl-9-borabicyclo[3.3.2]decane (1R, Soderquist’s borane) has been developed. Density functional theory calculations suggest that the allene hydroboration involves the 1,4-reduction of 2 with the chiral borane 1R, leading directly to dienolborinate Z-(O)-8a. PMID:24138187

  19. 40 CFR 65.151 - Condensers used as control devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... providing a continuous record or a condenser exit (product side) temperature monitoring device capable of... parts per million by volume outlet concentration requirements as specified in § 65.63(a)(2), or 40 CFR... the design evaluation for storage vessels and low-throughput transfer rack controls. As provided...

  20. Basic Program Plan. Condensed Version.

    ERIC Educational Resources Information Center

    Stanford Univ., CA. Stanford Center for Research and Development in Teaching.

    This condensed version of the Basic Program Plan for the Stanford Center for Research and Development in Teaching (SCDRT) outlines the proposed plans of substantive programs over the next several years (beginning December 1, 1972). Information on projected costs and the Center's institutional capabilities for administering, reviewing, and…

  1. Approaching Bose-Einstein Condensation

    ERIC Educational Resources Information Center

    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…

  2. Condensing Algebra for Technical Mathematics.

    ERIC Educational Resources Information Center

    Greenfield, Donald R.

    Twenty Algebra-Packets (A-PAKS) were developed by the investigator for technical education students at the community college level. Each packet contained a statement of rationale, learning objectives, performance activities, performance test, and performance test answer key. The A-PAKS condensed the usual sixteen weeks of algebra into a six-week…

  3. Condensation during Titan's Polar Winter

    NASA Astrophysics Data System (ADS)

    de Kok, Remco; Irwin, P. G.; Teanby, N. A.; Fletcher, L. N.; Howett, C. J.; Calcutt, S. B.; Bowles, N. E.; Taylor, F. W.

    2007-10-01

    Titan is currently experiencing winter in its northern hemisphere and the lower atmosphere of its north polar region has been in prolonged darkness since the solstice in October 2002. As a result, the north polar region is currently characterised by cold stratospheric temperatures and there is enrichment of trace gases due to downward atmospheric motion (e.g. Teanby et al., Icarus 181 pp. 243-255, 2006). These conditions make the polar winter very suitable for cloud formation in the stratosphere. A simple transport and condensation model has been made to explore condensation processes in Titan's northern stratosphere. In the model, the atmosphere is advected downwards and clouds are formed as the saturation pressure of various gases is reached. Upper limits of the gases C4N2 and propionitrile (C2H5CN) were determined from Cassini Composite Infrared Spectrometer data to assess scenarios of chemical disequilibrium where the gas phase is far less abundant than the solid phase. The upper limit for C4N2 is 9e-9, which discounts the massive C4N2 build-up in the polar winter proposed by Samuelson et al. (PSS 45, pp. 941-948, 1997) to explain the observed C4N2 cloud at the Voyager epoch. The propionitrile upper limit is 8e-9, which is several orders of magnitude less than needed to create the condensate feature at 220 cm-1 of Khanna (Icarus 177, pp. 116-121) and de Kok et al. (Icarus, in press), assuming it is propionitrile ice, under the steady-state conditions explored by the aformentioned model. HCN ice seems to play an important role in the formation of a massive polar cloud (Haze B in de Kok et al., Icarus, in press), because of the unavailability of sufficient condensable gas other than HCN (and possibly HC3N) to produce the condensate features seen in far-infrared spectra at 220 cm-1.

  4. Proceedings: 2000 Workshop on Condensate Polishing

    SciTech Connect

    2001-06-01

    Condensate polishing maintains control of impurities in the nuclear power plant and allows the unit to operate more reliably. This report presents proceedings of EPRI's 2000 Workshop on Condensate Polishing, where 30 papers were presented on current issues and utility experience involving condensate polishing at both pressurized water reactor (PWR) and boiling water reactor (BWR) plants.

  5. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1992-01-01

    Condensation heat transfer in an annular flow regime with and without interfacial waves was experimentally investigated. The study included measurements of heat transfer rate with condensation of vapor flowing inside a horizontal rectangular duct and experiments on the initiation of interfacial waves in condensation, and adiabatic air-liquid flow. An analytical model for the condensation was developed to predict condensate film thickness and heat transfer coefficients. Some conclusions drawn from the study are that the condensate film thickness was very thin (less than 0.6 mm). The average heat transfer coefficient increased with increasing the inlet vapor velocity. The local heat transfer coefficient decreased with the axial distance of the condensing surface, with the largest change at the leading edge of the test section. The interfacial shear stress, which consisted of the momentum shear stress and the adiabatic shear stress, appeared to have a significant effect on the heat transfer coefficients. In the experiment, the condensate flow along the condensing surface experienced a smooth flow, a two-dimensional wavy flow, and a three-dimensional wavy flow. In the condensation experiment, the local wave length decreased with the axial distance of the condensing surface and the average wave length decreased with increasing inlet vapor velocity, while the wave speed increased with increasing vapor velocity. The heat transfer measurements are reliable. And, the ultrasonic technique was effective for measuring the condensate film thickness when the surface was smooth or had waves of small amplitude.

  6. Condensed tannins from Ficus virens as tyrosinase inhibitors: structure, inhibitory activity and molecular mechanism.

    PubMed

    Chen, Xiao-Xin; Shi, Yan; Chai, Wei-Ming; Feng, Hui-Ling; Zhuang, Jiang-Xing; Chen, Qing-Xi

    2014-01-01

    Condensed tannins from Ficus virens leaves, fruit, and stem bark were isolated and their structures characterized by 13C nuclear magnetic resonance spectrometry, high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The results showed that the leaves, fruit, and stem bark condensed tannins were complex mixtures of homo- and heteropolymers of B-type procyanidins and prodelphinidins with degrees of polymerization up to hexamer, dodecamer, and pentadecamer, respectively. Antityrosinase activities of the condensed tannins were studied. The results indicated that the condensed tannins were potent tyrosinase inhibitors. The concentrations for the leaves, fruit, and stem bark condensed tannins leading to 50% enzyme activity were determined to be 131.67, 99.89, and 106.22 μg/ml on monophenolase activity, and 128.42, 43.07, and 74.27 μg/ml on diphenolase activity. The inhibition mechanism, type, and constants of the condensed tannins on the diphenolase activity were further investigated. The results indicated that the condensed tannins were reversible and mixed type inhibitors. Fluorescence quenching, copper interacting, and molecular docking techniques were utilized to unravel the molecular mechanisms of the inhibition. The results showed that the hydroxyl group on the B ring of the condensed tannins could chelate the dicopper irons of the enzyme. Moreover, the condensed tannins could reduce the enzyme product o-quinones into colourless compounds. These results would contribute to the development and design of antityrosinase agents.

  7. Condensed matter analogues of cosmology

    NASA Astrophysics Data System (ADS)

    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

  8. Anderson and Condensed Matter Physics

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, T. V.

    The legacy of P. W. Anderson, perhaps the most fertile and influential condensed matter physicist of the second half of the twentieth century, is briefly mentioned here. I note three pervasive values. They are: emergence with its constant tendency to surprise us and to stretch our imagination, the Baconian emphasis on the experimental moorings of modern science, and mechanism as the explanatory core. Out of his work, which is spread over more than six decades and in many ways has charted modern condensed matter physics, nearly a dozen seminal contributions, chosen idiosyncratically, are mentioned at the risk of leaving out many which may also have started subfields. Some of these are: antiferromagnestism and broken symmetry, superexchange and strong electron correlations, localization in disordered systems, gauge invariance and mass, and the resonating valence bond in magnetic systems as well as in high-temperature superconductivity...

  9. Wealth condensation in pareto macroeconomies.

    PubMed

    Burda, Z; Johnston, D; Jurkiewicz, J; Kamiński, M; Nowak, M A; Papp, G; Zahed, I

    2002-02-01

    We discuss a Pareto macroeconomy (a) in a closed system with fixed total wealth and (b) in an open system with average mean wealth, and compare our results to a similar analysis in a super-open system (c) with unbounded wealth [J.-P. Bouchaud and M. Mézard, Physica A 282, 536 (2000)]. Wealth condensation takes place in the social phase for closed and open economies, while it occurs in the liberal phase for super-open economies. In the first two cases, the condensation is related to a mechanism known from the balls-in-boxes model, while in the last case, to the nonintegrable tails of the Pareto distribution. For a closed macroeconomy in the social phase, we point to the emergence of a "corruption" phenomenon: a sizeable fraction of the total wealth is always amassed by a single individual.

  10. Wealth condensation in pareto macroeconomies

    NASA Astrophysics Data System (ADS)

    Burda, Z.; Johnston, D.; Jurkiewicz, J.; Kamiński, M.; Nowak, M. A.; Papp, G.; Zahed, I.

    2002-02-01

    We discuss a Pareto macroeconomy (a) in a closed system with fixed total wealth and (b) in an open system with average mean wealth, and compare our results to a similar analysis in a super-open system (c) with unbounded wealth [J.-P. Bouchaud and M. Mézard, Physica A 282, 536 (2000)]. Wealth condensation takes place in the social phase for closed and open economies, while it occurs in the liberal phase for super-open economies. In the first two cases, the condensation is related to a mechanism known from the balls-in-boxes model, while in the last case, to the nonintegrable tails of the Pareto distribution. For a closed macroeconomy in the social phase, we point to the emergence of a ``corruption'' phenomenon: a sizeable fraction of the total wealth is always amassed by a single individual.

  11. Atomistic modeling of dropwise condensation

    NASA Astrophysics Data System (ADS)

    Sikarwar, B. S.; Singh, P. L.; Muralidhar, K.; Khandekar, S.

    2016-05-01

    The basic aim of the atomistic modeling of condensation of water is to determine the size of the stable cluster and connect phenomena occurring at atomic scale to the macroscale. In this paper, a population balance model is described in terms of the rate equations to obtain the number density distribution of the resulting clusters. The residence time is taken to be large enough so that sufficient time is available for all the adatoms existing in vapor-phase to loose their latent heat and get condensed. The simulation assumes clusters of a given size to be formed from clusters of smaller sizes, but not by the disintegration of the larger clusters. The largest stable cluster size in the number density distribution is taken to be representative of the minimum drop radius formed in a dropwise condensation process. A numerical confirmation of this result against predictions based on a thermodynamic model has been obtained. Results show that the number density distribution is sensitive to the surface diffusion coefficient and the rate of vapor flux impinging on the substrate. The minimum drop radius increases with the diffusion coefficient and the impinging vapor flux; however, the dependence is weak. The minimum drop radius predicted from thermodynamic considerations matches the prediction of the cluster model, though the former does not take into account the effect of the surface properties on the nucleation phenomena. For a chemically passive surface, the diffusion coefficient and the residence time are dependent on the surface texture via the coefficient of friction. Thus, physical texturing provides a means of changing, within limits, the minimum drop radius. The study reveals that surface texturing at the scale of the minimum drop radius does not provide controllability of the macro-scale dropwise condensation at large timescales when a dynamic steady-state is reached.

  12. Condensation on Slippery Asymmetric Bumps

    NASA Astrophysics Data System (ADS)

    Park, Kyoo-Chul; Kim, Philseok; Aizenberg, Joanna

    Controlling dropwise condensation by designing surfaces that enable droplets to grow rapidly and be shed as quickly as possible is fundamental to water harvesting systems, thermal power generation, distillation towers, etc. However, cutting-edge approaches based on micro/nanoscale 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 couples both aspects of condensation and outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle's bump geometry in promoting condensation, we show how to maximize vapor diffusion flux at the apex of convex millimetric bumps by optimizing curvature and shape. Integrating this apex geometry with a widening slope analogous to cactus spines couples rapid drop growth with fast directional transport, by creating a free energy profile that drives the drop down the slope. This coupling is further enhanced by a slippery, pitcher plant-inspired coating that facilitates feedback between coalescence-driven growth and capillary-driven motion. We further observe an unprecedented six-fold higher exponent in growth rate and much faster shedding time compared to other surfaces. We envision that our fundamental understanding and rational design strategy can be applied to a wide range of phase change applications.

  13. Extreme-UV lithography condenser

    DOEpatents

    Sweatt, William C.; Sweeney, Donald W.; Shafer, David; McGuire, James

    2001-01-01

    Condenser system for use with a ringfield camera in projection lithography where the condenser includes a series of segments of a parent aspheric mirror having one foci at a quasi-point source of radiation and the other foci at the radius of a ringfield have all but one or all of their beams translated and rotated by sets of mirrors such that all of the beams pass through the real entrance pupil of a ringfield camera about one of the beams and fall onto the ringfield radius as a coincident image as an arc of the ringfield. The condenser has a set of correcting mirrors with one of the correcting mirrors of each set, or a mirror that is common to said sets of mirrors, from which the radiation emanates, is a concave mirror that is positioned to shape a beam segment having a chord angle of about 25 to 85 degrees into a second beam segment having a chord angle of about 0 to 60 degrees.

  14. Properties of fragmented repulsive condensates

    SciTech Connect

    Streltsov, Alexej I.; Cederbaum, Lorenz S.

    2005-06-15

    Repulsive Bose-Einstein condensates immersed into a double-well trap potential are studied within the framework of the recently introduced mean-field approach which allows for bosons to reside in several different orthonormal orbitals. In the case of a one-orbital mean-field theory (Gross-Pitaevskii) the ground state of the system reveals a bifurcation scenario at some critical values of the interparticle interaction and/or the number of particles. At about the same values of the parameters the two-orbital mean field predicts that the system becomes twofold fragmented. By applying the three-orbital mean field we verify numerically that for the double-well external potential studied here the overall best mean field is achieved with two orbitals. The variational principle minimizes the energy at a vanishing population of the third orbital. To discuss the energies needed to remove a boson from and the energies gained by adding a boson to the condensate, we introduce boson ionization potentials and boson affinities and relate them to the chemical potentials. The impact of the finite number of bosons in the condensate on these quantities is analyzed. We recall that within the framework of the multiorbital mean-field theory each fragment is characterized by its own chemical potential. Finally, the stability of fragmented states is discussed in terms of the boson transfer energy which is the energy needed to transfer a boson from one fragment to another.

  15. Condensation shocks in hypersonic nitrogen tunnels

    NASA Technical Reports Server (NTRS)

    Hudson, Susan T.; Griffith, Wayland C.; Lederer, Melissa; Ragsdale, William C.; Yanta, William J.

    1990-01-01

    Experimental observations and a theoretical model for the onset and disappearance of condensation are provided for hypersonic flows of pure nitrogen at M = 10, 14, and 18. A method for analyzing the thermodynamic and flow properties of a partially condensed mixture from known supply conditions and measured Pitot pressure yields the local static pressure and temperature, mass fraction of the nitrogen condensed, and the Mach number of the partially condensed flow based on frozen sound speed. The transition between partially condensed-supercooled flow is found to occur at 22-25 K isobaric supercooling with the corresponding mass fraction condensed being 12-14 percent over a range of two orders of magnitude in local static pressure. The heat released and vapor mass removed during condensation ultimately raise the local pressure and temperature and reduce the flow Mach number.

  16. Invited papers presented to a workshop on thermodynamics and kinetics of dust formation in the space medium. [condensation, nucleation, and interstellar dust

    NASA Technical Reports Server (NTRS)

    Robertson, P. C.

    1978-01-01

    Abstracts of 25 papers relating to condensation processes in the early solar system are presented. Special emphasis is given to the transition of an initial vapor phase in the space medium, the characterization of condensation environments, and condensation processes in the space medium. The question of whether some fraction of the solar system solids (particularly exemplified by meteoritic solids) may be interstellar grains that gathered in the region of the proto-sun, rather than being products of local condensation is addressed.

  17. Studies of the condensation of sulfones with ketones and aldehydes.

    PubMed

    Garst, Michael E; Dolby, Lloyd J; Esfandiari, Shervin; Okrent, Rachel A; Avey, Alfred A

    2006-01-20

    [reaction: see text] The condensation of ketones or aldehydes with sulfones was shown to give a variety of products. Condensation of 2-methylcyclohexanone with dimethyl sulfone using potassium t-butoxide as base gave useful yields of 1,2-dimethylenecyclohexane. Under the same conditions, cycloheptanone, 3-methyl-2-butanone, and 2-butanone were converted to dienes. Remarkably, these reaction conditions converted acetophenone into p-terphenyl (10%) and (E)-1,4-diphenyl-3-penten-1-one (44%). Propiophenone was converted to 2'-methyl-p-terphenyl (61%). Using alpha-tetralone produced 1-methynaphthalene and naphthalene. No reaction took place with beta-tetralone. Using diethyl sulfone with alpha-tetralone lead to pure naphthalene. Condensation of isobutyraldehyde and dimethyl sulfone using potassium t-butoxide gave isoprene in low yield. Using benzaldehyde and benzyl phenyl sulfone in N,N-dimethylacetamide gave 1,2-diphenyl-1-phenylsulfonylethylene, N,N-dimethylcinnamide, and a complex condensation product. Only 1,2-diphenyl-1-phenylsulfonylethylene was obtained when the solvent was THF. PMID:16408963

  18. Condensing efficiency of the truncated cone condenser and its comparison with the Winston cone condenser in terahertz region

    NASA Astrophysics Data System (ADS)

    Aoki, Makoto; Hiromoto, Norihisa

    2015-01-01

    The angle-dependent condensing efficiency of a truncated cone condenser (TCC) in the terahertz (THz) region has been examined by 2D ray tracing and 3D electromagnetic simulation. The condensing efficiency in the THz region is transferred to that in the optical region by theoretical dispersive reflection from a rough surface, and it is confirmed that the latter is consistent with the measured condensing efficiency in the optical region. Although the TCC has a gradual field of view (FOV) compared with the Winston cone condenser (WCC), we improved the steepness of the FOV by adding a baffle before the input aperture of the TCC. We also proved that the TCC has a high condensing efficiency at around normal incidence in comparison with the WCC in the THz region.

  19. CDW-Exciton Condensate Competition and a Condensate Driven Force

    NASA Astrophysics Data System (ADS)

    Özgün, Ege; Hakioğlu, Tuğrul

    2016-08-01

    We examine the competition between the charge-density wave (CDW) instability and the excitonic condensate (EC) in spatially separated layers of electrons and holes. The CDW and the EC order parameters (OPs), described by two different mechanisms and hence two different transition temperatures TcCDW and TcEC, are self-consistently coupled by a microscopic mean field theory. We discuss the results in our model specifically focusing on the transition-metal dichalcogenides which are considered as the most typical examples of strongly coupled CDW/EC systems with atomic layer separations where the electronic energy scales are large with the critical temperatures in the range TcEC ˜ TcCDW ˜ 100-200 K. An important consequence of this is that the excitonic energy gap, hence the condensed free energy, vary with the layer separation resulting in a new type of force FEC. We discuss the possibility of this force as the possible driver of the structural lattice deformation observed in some TMDCs with a particular attention on the 1T-TiSe2 below 200 K.

  20. Linked strategy for the production of fuels via formose reaction

    PubMed Central

    Deng, Jin; Pan, Tao; Xu, Qing; Chen, Meng-Yuan; Zhang, Ying; Guo, Qing-Xiang; Fu, Yao

    2013-01-01

    Formose reaction converts formaldehyde to carbohydrates. We found that formose reaction can be used linking the biomass gasification with the aqueous-phase processing (APP) to produce liquid transportation fuel in three steps. First, formaldehyde from syn-gas was converted to triose. This was followed by aldol condensation and dehydration to 4-hydroxymethylfurfural (4-HMF). Finally, 4-HMF was hydrogenated to produce 2,4-dimethylfuran (2,4-DMF) or C9-C15 branched-chain alkanes as liquid transportation fuels. In the linked strategy, high energy-consuming pretreatment as well as expensive and polluting hydrolysis of biomass were omitted, but the high energy recovery of APP was inherited. In addition, the hexoketoses via formose reaction could be converted to HMFs directly without isomerization. A potential platform molecule 4-HMF was formed simultaneously in APP. PMID:23393625

  1. Linked strategy for the production of fuels via formose reaction.

    PubMed

    Deng, Jin; Pan, Tao; Xu, Qing; Chen, Meng-Yuan; Zhang, Ying; Guo, Qing-Xiang; Fu, Yao

    2013-01-01

    Formose reaction converts formaldehyde to carbohydrates. We found that formose reaction can be used linking the biomass gasification with the aqueous-phase processing (APP) to produce liquid transportation fuel in three steps. First, formaldehyde from syn-gas was converted to triose. This was followed by aldol condensation and dehydration to 4-hydroxymethylfurfural (4-HMF). Finally, 4-HMF was hydrogenated to produce 2,4-dimethylfuran (2,4-DMF) or C(9)-C(15) branched-chain alkanes as liquid transportation fuels. In the linked strategy, high energy-consuming pretreatment as well as expensive and polluting hydrolysis of biomass were omitted, but the high energy recovery of APP was inherited. In addition, the hexoketoses via formose reaction could be converted to HMFs directly without isomerization. A potential platform molecule 4-HMF was formed simultaneously in APP. PMID:23393625

  2. Condensation on slippery asymmetric bumps

    NASA Astrophysics Data System (ADS)

    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

  3. Condensation on slippery asymmetric bumps.

    PubMed

    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

  4. Condensation on slippery asymmetric bumps.

    PubMed

    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

  5. Tachyon condensation on brane sphalerons

    NASA Astrophysics Data System (ADS)

    Brito, Francisco A.

    2005-08-01

    We consider a sphaleron solution in field theory that provides a toy model for unstable D-branes of string theory. We investigate the tachyon condensation on a Dp-brane. The localized modes, including a tachyon, arise in the spectrum of a sphaleron solution of a phi4 field theory on Bbb Mp+1 × S1. We use these modes to find a multiscalar tachyon potential living on the sphaleron world-volume. A complete cancelation between brane tension and the minimum of the tachyon potential is found as the size of the circle becomes small.

  6. Turbulent Distortion of Condensate Accretion

    NASA Technical Reports Server (NTRS)

    Hazoume, R.; Orou Chabi, J.; Johnson, J. A., III

    1997-01-01

    When a simple model for the relationship between the density-temperature fluctuation correlation and mean values is used, we determine that the rate of change of turbulent intensity can influence directly the accretion rate of droplets. Considerable interest exists in the accretion rate for condensates in nonequilibrium flow with icing and the potential role which reactant accretion can play in nonequilibrium exothermic reactant processes. Turbulence is thought to play an important role in such flows. It has already been experimentally determined that turbulence influences the sizes of droplets in the heterogeneous nucleation of supersaturated vapors. This paper addresses the issue of the possible influence of turbulence on the accretion rate of droplets.

  7. Predictive thermodynamics for condensed phases.

    PubMed

    Glasser, Leslie; Jenkins, H Donald Brooke

    2005-10-01

    Thermodynamic information is central to assessment of the stability and reactivity of materials. However, because of both the demanding nature of experimental thermodynamics and the virtually unlimited number of conceivable compounds, experimental data is often unavailable or, for hypothetical materials, necessarily impossible to obtain. We describe simple procedures for thermodynamic prediction for condensed phases, both ionic and organic covalent, principally via formula unit volumes (or density); our volume-based approach (VBT) provides a new thermodynamic tool for such assessment. These methods, being independent of detailed knowledge of crystal structures, are applicable to liquids and amorphous materials as well as to crystalline solids. Examples of their use are provided. PMID:16172676

  8. Velocity Condensation for Magnetotactic Bacteria

    NASA Astrophysics Data System (ADS)

    Rupprecht, Jean-François; Waisbord, Nicolas; Ybert, Christophe; Cottin-Bizonne, Cécile; Bocquet, Lydéric

    2016-04-01

    Magnetotactic swimmers tend to align along magnetic field lines against stochastic reorientations. We show that the swimming strategy, e.g., active Brownian motion versus run-and-tumble dynamics, strongly affects the orientation statistics. The latter can exhibit a velocity condensation whereby the alignment probability density diverges. As a consequence, we find that the swimming strategy affects the nature of the phase transition to collective motion, indicating that Lévy run-and-tumble walks can outperform active Brownian processes as strategies to trigger collective behavior.

  9. Process for gasifying carbonaceous material from a recycled condensate slurry

    DOEpatents

    Forney, Albert J.; Haynes, William P.

    1981-01-01

    Coal or other carbonaceous material is gasified by reaction with steam and oxygen in a manner to minimize the problems of effluent water stream disposal. The condensate water from the product gas is recycled to slurry the coal feed and the amount of additional water or steam added for cooling or heating is minimized and preferably kept to a level of about that required to react with the carbonaceous material in the gasification reaction. The gasification is performed in a pressurized fluidized bed with the coal fed in a water slurry and preheated or vaporized by indirect heat exchange contact with product gas and recycled steam. The carbonaceous material is conveyed in a gas-solid mixture from bottom to top of the pressurized fluidized bed gasifier with the solids removed from the product gas and recycled steam in a supported moving bed filter of the resulting carbonaceous char. Steam is condensed from the product gas and the condensate recycled to form a slurry with the feed coal carbonaceous particles.

  10. Axions: Bose Einstein condensate or classical field?

    NASA Astrophysics Data System (ADS)

    Davidson, Sacha

    2015-05-01

    The axion is a motivated dark matter candidate, so it would be interesting to find features in Large Scale Structures specific to axion dark matter. Such features were proposed for a Bose Einstein condensate of axions, leading to confusion in the literature (to which I contributed) about whether axions condense due to their gravitational interactions. This note argues that the Bose Einstein condensation of axions is a red herring: the axion dark matter produced by the misalignment mechanism is already a classical field, which has the distinctive features attributed to the axion condensate (BE condensates are described as classical fields). This note also estimates that the rate at which axion particles condense to the field, or the field evaporates to particles, is negligible.

  11. Production of alkyl-aromatics from light oxygenates over zeolite catalysts for bio-oil refining

    NASA Astrophysics Data System (ADS)

    Hoang, Trung Q.

    Upgrading of light oxygenates derived from biomass conversion, such as propanal and glycerol, to more valuable aromatics for biofuels has been demonstrated on zeolite catalysts. Aromatics with a high ratio of C 9/(C8+C7) and little benzene are produced at much higher yield from oxygenates than from olefins at mild conditions over HZSM-5. It is proposed that C9 aromatics are predominantly produced via acid-catalyzed aldol condensation. This reaction pathway is different from the pathway of propylene and other hydrocarbon aromatization that occurs via a hydrocarbon pool at more severe conditions with major aromatic products C6 and C7. In fact, investigation on the effect of crystallite size HZSM-5 has shown a higher ratio of C9/(C8+C 7) aromatics on small crystallite. This is due to faster removal of products from the shorter diffusion path length. As a result, a longer catalyst lifetime, less isomerization, and less cracking were observed on small crystallites. Beside crystallite size, pore geometry of zeolites was also found to significantly affect aromatic production for both conversion of propanal and glycerol. It is shown that the structure of the HZSM-22, with a one-dimensional and narrower channel system, restricts the formation of aromatics. In contrast, a higher yield of aromatic products is observed over HZSM-5 with its three-dimensional channel system. By increasing channel dimension and connectivity of the channels, increasing catalyst activity was also observed due to more accessible acid sites. It was also found that glycerol is highly active for dehydration on zeolites to produce high yields of acrolein (propenal), a high value chemical. To maximize aromatics from glycerol conversion, HZSM-5 and HY were found to be effective. A two-bed reactor of Pd/ZnO and HZSM-5 was used to first deoxygenate/hydrogenate glycerol over Pd/ZnO to intermediate oxygenates that can further aromatize on HZSM-5. The end results are very promising with significant improvement

  12. High-temperature condensates in carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Grossman, L.

    1977-01-01

    Equilibrium thermodynamic calculations of the sequence of condensation of minerals from a cooling gas of solar composition play an important role in explaining the mineralogy and trace element content of different types of inclusions in carbonaceous chondrites. Group IV B iron meteorites and enstatite chondrites may also be direct condensates from the solar nebula. Condensation theory provides a framework within which chemical fractionations between different classes of chondrites may be understood.

  13. Bose-Einstein condensation of cesium.

    PubMed

    Weber, Tino; Herbig, Jens; Mark, Michael; Nägerl, Hanns-Christoph; Grimm, Rudolf

    2003-01-10

    Bose-Einstein condensation of cesium atoms is achieved by evaporative cooling using optical trapping techniques. The ability to tune the interactions between the ultracold atoms by an external magnetic field is crucial to obtain the condensate and offers intriguing features for potential applications. We explore various regimes of condensate self-interaction (attractive, repulsive, and null interaction strength) and demonstrate properties of imploding, exploding, and non-interacting quantum matter. PMID:12471267

  14. Condensation induced water hammer safety

    SciTech Connect

    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.

  15. The Mukaiyama aldol reaction of in situ generated nitrosocarbonyl compounds: selective C-N bond formation and N-O bond cleavage in one-pot for α-amination of ketones.

    PubMed

    Ramakrishna, Isai; Grandhi, Gowri Sankar; Sahoo, Harekrishna; Baidya, Mahiuddin

    2015-09-21

    A practical protocol for the α-amination of ketones (up to 99% yield) has been developed via the Mukaiyama aldol reaction of in situ generated nitrosocarbonyl compounds. The reaction with silyl enol ethers having a disilane (-SiMe2TMS) backbone proceeded not only with perfect N-selectivity but concomitant N-O bond cleavage was also accomplished. Such a cascade of C-N bond formation and N-O bond cleavage in a single step was heretofore unknown in the field of nitrosocarbonyl chemistry. A very high diastereoselectivity (dr = 19 : 1) was accomplished using (-)-menthol derived chiral nitrosocarbonyl compounds. PMID:26245149

  16. Enhanced condensation heat transfer with wettability patterning

    NASA Astrophysics Data System (ADS)

    Sinha Mahapatra, Pallab; Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Condensation of water vapor on metal surfaces is useful for many engineering applications. A facile and scalable method is proposed for removing condensate from a vertical plate during dropwise condensation (DWC) in the presence of non-condensable gases (NCG). We use wettability-patterned superhydrophilic tracks (filmwise condensing domains) on a mirror-finish (hydrophilic) aluminum surface that promotes DWC. Tapered, horizontal ``collection'' tracks are laid to create a Laplace pressure driven flow, which collects condensate from the mirror-finish domains and sends it to vertical ``drainage tracks'' for gravity-induced shedding. An optimal design is achieved by changing the fractional area of superhydrophilic tracks with respect to the overall plate surface, and augmenting capillary-driven condensate-drainage by adjusting the track spatial layout. The design facilitates pump-less condensate drainage and enhances DWC heat transfer on the mirror-finish regions. The study highlights the relative influences of the promoting and retarding effects of dropwise and filmwise condensation zones on the overall heat transfer improvement on the substrate. The study demonstrated ~ 34% heat transfer improvement on Aluminum surface for the optimized design.

  17. Reflux condensation in a closed tube

    SciTech Connect

    Tien, C.L.

    1984-10-01

    Reflux condensation which may have an appreciable effect on the reflood process in the reactor core during the loss-of-coolant accident is investigated experimentally and analytically in the present work using the vertical two-phase closed thermosyphon. The condensation heat transfer coefficients of the countercurrent vapor-liquid flows are locally measured along the condenser wall. The results indicate that Nusselt's solution for film condensation cannot interpret satisfactorily the observed trend. Further improvements are made to consider the effects of interfacial shear, waviness and non-condensable gas on condensation. The vapor shear retards the condensate flow and thus increases the film thickness, which results in lower heat transfer coefficients than those calculated from Nusselt theory. Modified Fanning friction factors which account for the augmentation of interfacial shear through phase change are used to evaluate the reduction of heat transfer by vapor shear. On the other hand, the waves appearing on the interface can enhance heat transfer rates. Such enhancement is determined by solving numerically the nonlinear equation for the wavy interface. When non-condensable gases are present in the system, they will accumulate at the condenser end forming a gas barrier to the vapor and shut off that portion. A two-dimensional model is developed to include both axial and radial diffusion of gas mass. This two-dimensional analysis indicates the inadequacy of the common one-dimensional diffuse-front model in considering only axial diffusion of gas in most physical systems.

  18. Advances in modelling of condensation phenomena

    SciTech Connect

    Liu, W.S.; Zaltsgendler, E.; Hanna, B.

    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.

  19. Water Condensation Kinetics on a Hydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Linderoth, Trolle R.; Zhdanov, Vladimir P.; Kasemo, Bengt

    2003-04-01

    Employing thermal desorption spectroscopy, we show that the effective probability of water condensation at low water vapor pressure on an octane film is much below unity at 100 120K. This unusual finding is related to a small binding energy of H2O monomers on octane (≃0.08 eV), requiring the formation of critical water clusters for condensation to occur. This results in strong temperature and impingement-rate dependencies of the water condensation rate and a nonlinear uptake as a function of dose time. All these features are rationalized quantitatively by a kinetic model of water condensation.

  20. Treatment of evaporator condensates by pervaporation

    DOEpatents

    Blume, Ingo; Baker, Richard W.

    1990-01-01

    A pervaporation process for separating organic contaminants from evaporator condensate streams is disclosed. The process employs a permselective membrane that is selectively permeable to an organic component of the condensate. The process involves contacting the feed side of the membrane with a liquid condensate stream, and withdrawing from the permeate side a vapor enriched in the organic component. The driving force for the process is the in vapor pressure across the membrane. This difference may be provided for instance by maintaining a vacuum on the permeate side, or by condensing the permeate. The process offers a simple, economic alternative to other separation techniques.

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

    EPA Science Inventory

    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...

  2. Diastereoselective one-pot Knoevenagel condensation/Corey-Chaykovsky cyclopropanation.

    PubMed

    Clemens, Jeremy J; Asgian, Juliana L; Busch, Brett B; Coon, Timothy; Ernst, Justin; Kaljevic, Leonard; Krenitsky, Paul J; Neubert, Timothy D; Schweiger, Edwin J; Termin, Andreas; Stamos, Dean

    2013-01-18

    Efforts to substitute the cyclopropane ring in a series of aryl cyclopropylnitriles led to the discovery of an operationally simple one-pot method for Knoevenagel condensation and subsequent Corey-Chaykovsky cyclopropanation giving diastereomerically pure products as a racemic mixture of enantiomers. Method development and results for variably substituted aryl acetonitriles and aldehydes in the reaction are reported. A concise synthesis of (±)-bicifadine in two steps is provided to demonstrate the utility of the method. PMID:23252964

  3. Traceless OH-Directed Wacker Oxidation-Elimination, an Alternative to Wittig Olefination/Aldol Condensation: One-Pot Synthesis of α,β-Unsaturated and Nonconjugated Ketones from Homoallyl Alcohols.

    PubMed

    Bethi, Venkati; Fernandes, Rodney A

    2016-09-16

    A new method for one-pot synthesis of β-substituted and β,β-disubstituted α,β-unsaturated methyl ketones from homoallyl alcohols by sequential PdCl2/CrO3-promoted Wacker process followed by an acid-mediated dehydration reaction has been developed. Remarkably, internal homoallyl alcohols delivered regioselectively nonconjugated unsaturated carbonyl compounds under the same protocol. A new starting material-based synthesis of α,β-unsaturated and nonconjugated methyl ketones is demonstrated.

  4. Traceless OH-Directed Wacker Oxidation-Elimination, an Alternative to Wittig Olefination/Aldol Condensation: One-Pot Synthesis of α,β-Unsaturated and Nonconjugated Ketones from Homoallyl Alcohols.

    PubMed

    Bethi, Venkati; Fernandes, Rodney A

    2016-09-16

    A new method for one-pot synthesis of β-substituted and β,β-disubstituted α,β-unsaturated methyl ketones from homoallyl alcohols by sequential PdCl2/CrO3-promoted Wacker process followed by an acid-mediated dehydration reaction has been developed. Remarkably, internal homoallyl alcohols delivered regioselectively nonconjugated unsaturated carbonyl compounds under the same protocol. A new starting material-based synthesis of α,β-unsaturated and nonconjugated methyl ketones is demonstrated. PMID:27562136

  5. Zero-temperature damping of Bose-Einstein condensate oscillations by vortex-antivortex pair creation

    SciTech Connect

    Fedichev, Petr O.; Fischer, Uwe R.; Recati, Alessio

    2003-07-01

    We investigate vortex-antivortex pair creation in a supersonically expanding and contracting quasi-two-dimensional Bose-Einstein condensate at zero temperature. For sufficiently large-amplitude condensate oscillations, pair production provides the leading dissipation mechanism. The condensate oscillations decay in a nonexponential manner, and the dissipation rate depends strongly on the oscillation amplitude. These features allow one to distinguish the decay due to pair creation from other possible damping mechanisms. An experimental observation of the predicted oscillation behavior of the superfluid gas provides a direct confirmation of the hydrodynamical analogy of quantum electrodynamics and quantum vortex dynamics in two spatial dimensions.

  6. Bose-Einstein-condensate heating by atomic losses

    SciTech Connect

    Dziarmaga, Jacek; Sacha, Krzysztof

    2003-10-01

    Atomic Bose-Einstein condensate is heated by atomic losses. The losses act as a heat reservoir for the condensate. The condensate is approaching a state of thermal equilibrium with a thermal depletion ranging from 1% for a uniform three-dimensional (3D) condensate to around 13% for a quasi-1D condensate in a harmonic trap.

  7. CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers.

    PubMed

    Li, Jun-De

    2013-02-01

    This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected.

  8. CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers

    PubMed Central

    Li, Jun-De

    2013-01-01

    This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

  9. Chemical remediation of beech condensates.

    PubMed

    Irmouli, Mohammed; Haluk, Jean Pierre

    2005-01-01

    In the present work, beech wood condensates are separated from the aqueous phase. Experimental results reveal an electrostatic interaction between the oppositely charged wood extracts after oxidation and Ca(OH)(2). The increase in aqueous phase pH resulted in enhanced removal of wood extracts from water. The polarographic assays were carried out at 25 degrees C using a Gilson oxygraph equipped with a Clark electrode in order to determine the oxygen uptake during the oxidation reaction. The effect of pH is explained based on oxygen uptake. The organic compounds found in the aqueous effluent are responsible for the brown color. The objective of this study is to find the optimum pH to eliminate the wood extracts from the liquid effluents. PMID:15567404

  10. Transient nucleation in condensed systems

    NASA Technical Reports Server (NTRS)

    Kelton, K. F.; Greer, A. L.; Thompson, C. V.

    1983-01-01

    Using classical nucleation theory we consider transient nucleation occurring in a one-component, condensed system under isothermal conditions. We obtain an exact closed-form expression for the time dependent cluster populations. In addition, a more versatile approach is developed: a numerical simulation technique which models directly the reactions by which clusters are produced. This simulation demonstrates the evolution of cluster populations and nucleation rate in the transient regime. Results from the simulation are verified by comparison with exact analytical solutions for the steady state. Experimental methods for measuring transient nucleation are assessed, and it is demonstrated that the observed behavior depends on the method used. The effect of preexisting cluster distributions is studied. Previous analytical and numerical treatments of transient nucleation are compared to the solutions obtained from the simulation. The simple expressions of Kashchiev are shown to give good descriptions of the nucleation behavior.

  11. Prebiotic condensation reactions using cyanamide

    NASA Technical Reports Server (NTRS)

    Sherwood, E.; Nooner, D. W.; Eichberg, J.; Epps, D. E.; Oro, J.

    1978-01-01

    Condensation reactions in cyanamide, 4-amino-5-imidazole-carboxamide and cyanamide, imidazole systems under dehydrating conditions at moderate temperatures (60 to 100 deg C) were investigated. The cyanamide, imidazole system was used for synthesis of palmitoylglycerols from ammonium palmitate and glycerol. With the addition of deoxythymidine to the former system, P1, P2-dideoxythymidine 5 prime-phosphate was obtained; the same cyanamide, 4-amino-5-imidazole-carboxamide system was used to synthesize deoxythymidine oligonucleotides using deoxythymidine 5 prime-phosphate and deoxythymidine 5 prime-triphosphate, and peptides using glycine, phenylalanine or isoleucine with adenosine 5 prime-triphosphate. The pH requirements for these reactions make their prebiotic significance questionable; however, it is conceivable that they could occur in stable pockets of low interlayer acidity in a clay such as montmorillonite.

  12. Tunable Vapor-Condensed Nanolenses

    PubMed Central

    2015-01-01

    Nanostructured optical components, such as nanolenses, direct light at subwavelength scales to enable, among others, high-resolution lithography, miniaturization of photonic circuits, and nanoscopic imaging of biostructures. A major challenge in fabricating nanolenses is the appropriate positioning of the lens with respect to the sample while simultaneously ensuring it adopts the optimal size and shape for the intended use. One application of particular interest is the enhancement of contrast and signal-to-noise ratio in the imaging of nanoscale objects, especially over wide fields-of-view (FOVs), which typically come with limited resolution and sensitivity for imaging nano-objects. Here we present a self-assembly method for fabricating time- and temperature-tunable nanolenses based on the condensation of a polymeric liquid around a nanoparticle, which we apply to the high-throughput on-chip detection of spheroids smaller than 40 nm, rod-shaped particles with diameter smaller than 20 nm, and biofunctionalized nanoparticles, all across an ultralarge FOV of >20 mm2. Previous nanoparticle imaging efforts across similar FOVs have detected spheroids no smaller than 100 nm, and therefore our results demonstrate the detection of particles >15-fold smaller in volume, which in free space have >240 times weaker Rayleigh scattering compared to the particle sizes detected in earlier wide-field imaging work. This entire platform, with its tunable nanolens condensation and wide-field imaging functions, is also miniaturized into a cost-effective and portable device, which might be especially important for field use, mobile sensing, and diagnostics applications, including, for example, the measurement of viral load in bodily fluids. PMID:24979060

  13. Molecular attraction of condensed bodies

    NASA Astrophysics Data System (ADS)

    Derjaguin, B. V.; Abrikosova, I. I.; Lifshitz, E. M.

    2015-09-01

    From the Editorial Board. As a contribution to commemorating the 100th anniversary of the birth of Evgenii Mikhailovich Lifshitz, it was found appropriate by the Editorial Board of Uspekhi Fizicheskikh Nauk (UFN) [Physics-Uspekhi] journal that the materials of the jubilee-associated Scientific Session of the Physical Sciences Division of the Russian Academy of Sciences published in this issue (pp. 877-905) be augmented by the review paper "Molecular attraction of condensed bodies" reproduced from a 1958 UFN issue. Included in this review, in addition to an account by Evgenii Mikhailovich Lifshitz of his theory of molecular attractive forces between condensed bodies (first published in Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki (ZhETF) in 1955 and in its English translation Journal of Experimental and Theoretical Physics (JETP) in 1956), is a summary of a series of experimental studies beginning in 1949 by Irina Igorevna Abrikosova at the Institute of Physical Chemistry of the Academy of Sciences of the USSR in a laboratory led by Boris Vladimirovich Derjaguin (1902-1994), a Corresponding Member of the USSR Academy of Sciences. In 1958, however, UFN was not yet available in English translation, so the material of the review is insufficiently accessible to the present-day English-speaking reader. This is the reason why the UFN Editorial Board decided to contribute to celebrating the 100th anniversary of E M Lifshitz's birthday by reproducing on the journal's pages a 1958 review paper which contains both E M Lifshitz's theory itself and the experimental data that underpinned it (for an account of how Evgenii Mikhailovich Lifshitz was enlisted to explain the experimental results of I I Abrikosova and B V Derjaguin, see the letter to the editors N P Danilova on page 925 of this jubilee collection of publications).

  14. Proceedings: 2002 Workshop on Condensate Polishing

    SciTech Connect

    2002-06-01

    Condensate polishing aims to control impurities in a nuclear power plant, thus allowing the unit to operate more reliably. This report contains the work presented at EPRI's 2002 Workshop on Condensate Polishing, where 36 papers were presented on current issues, research, and utility experiences involving polishing issues at both pressurized water reactor (PWR) and boiling water reactor (BWR) units.

  15. Soliton resonance in bose-einstein condensate

    NASA Technical Reports Server (NTRS)

    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.

  16. Collision of Bose Condensate Dark Matter structures

    SciTech Connect

    Guzman, F. S.

    2008-12-04

    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.

  17. Hydrophilic structures for condensation management in appliances

    DOEpatents

    Kuehl, Steven John; Vonderhaar, John J.; Wu, Guolian; Wu, Mianxue

    2016-02-02

    An appliance that includes a cabinet having an exterior surface; a refrigeration compartment located within the cabinet; and a hydrophilic structure disposed on the exterior surface. The hydrophilic structure is configured to spread condensation. The appliance further includes a wicking structure located in proximity to the hydrophilic structure, and the wicking structure is configured to receive the condensation.

  18. Dual condensate and QCD phase transition

    SciTech Connect

    Zhang Bo; Bruckmann, Falk; Fodor, Zoltan; Szabo, Kalman K.; Gattringer, Christof

    2011-05-23

    The dual condensate is a new QCD phase transition order parameter, which connnects confinement and chiral symmetry breaking as different mass limits. We discuss the relation between the fermion spectrum at general boundary conditions and the dual condensate and show numerical results for the latter from unquenched SU(3) lattice configurations.

  19. Quantum metrology with Bose-Einstein condensates

    SciTech Connect

    Boixo, Sergio; Datta, Animesh; Davis, Matthew J.; Flammia, Steven T.; Shaji, Anil; Tacla, Alexandre B.; Caves, Carlton M.

    2009-04-13

    We show how a generalized quantum metrology protocol can be implemented in a two-mode Bose-Einstein condensate of n atoms, achieving a sensitivity that scales better than 1/n and approaches 1/n{sup 3/2} for appropriate design of the condensate.

  20. Condensation of liquid metals under low pressures

    SciTech Connect

    Elafify, M.M.

    1988-01-01

    The Direct Simulation Monte Carlo (DSMC) method is used to study one-dimensional condensation phenomena for a pure vapor or vapor/gas mixture. The results are fitted to an interpolation formula describing the condensation mass flux to provide a usable engineering correlation. For pure vapor, the DSMC results are compared with the available experimental data for condensation of mercury under low pressure. Results are compared also with some of the theoretical models. The comparison shows that the DSMC method is able to detect the qualitative behavior of the condensation mass flux, although it overestimates the mass flux by 20-30%. Compared with other introduced theoretical models, the DSMC method has the most-consistent representation of the qualitative behavior of the condensation mass flux. The method was also used to represent condensation in the presence of a noncondensable gas. A formal proof for choosing collision partners was introduced and applied in the case of condensation in the presence of a noncondensable gas. The method is applied to condensation of mercury in the presence of different monatomic noncondensable gases at different partial pressures.

  1. Condensed Matter Theories - Volume 22

    NASA Astrophysics Data System (ADS)

    Reinholz, Heidi; Röpke, Gerd; de Llano, Manuel

    2007-09-01

    pt. A. Fermi liquids. Pressure comparison between the spherical cellular model and the Thomas-Fermi model / G.A. Baker, Jr. Pair excitations and vertex corrections in Fermi fluids and the dynamic structure function of two-dimension 3He / H.M. Böhm, H. Godfrin, E. Krotscheck, H.J. Lauter, M. Meschke and M. Panholzer. Condensation of helium in wedges / E.S. Hernádez ... [et al.]. Non-Fermi liquid behavior from the Fermi-liquid approach / V.A. Khodel ... [et al.]. Theory of third sound and stability of thin 3He-4He superfluid films / E. Krotscheck and M.D. Miller. Pairing in asymmetrical Fermi systems / K.F. Quader and R. Liao. Ground-state properties of small 3He drops from quantum Monte Carlo simulations / E. Sola, J. Casulleras and J. Boronat. Ground-state energy and compressibility of a disordered two-dimensional electron gas / Tanatar ... [et al.]. Quasiexcitons in photoluminescence of incompressible quantum liquids / A. Wójs, A.G ladysiewicz and J.J. Quinn -- pt. B. Bose liquids. Quantum Boltzmann liquids / K.A. Gernoth, M L. Ristig and T. Lindenau. Condensate fraction in the dynamic structure function of Bose fluids / M. Saarela, F. Mazzanti and V. Apaja -- pt. C. Strongly-correlated electronic systems. Electron gas in high-field nanoscopic transport: metallic carbon nanotubes / F. Green and D. Neilson. Evolution and destruction of the Kondo effect in a capacitively coupled double dot system / D.E. Logan and M.R. Galpin. The method of increments-a wavefunction-based Ab-Initio correlation method for solids / B. Paulus. Fractionally charged excitations on frustrated lattices / E. Runge, F. Pollmann and P. Fulde. 5f Electrons in actinides: dual nature and photoemission spectra / G. Zwicknagl -- pt. D. Magnetism. Magnetism in disordered two-dimensional Kondo-Necklace / W. Brenig. On the de Haas-can Alphen oscillation in 2D / S. Fujita and D.L. Morabito. Dynamics in one-dimensional spin systems-density matrix reformalization group study / S. Nishimoto and M

  2. Bose-Einstein condensation of chromium.

    PubMed

    Griesmaier, Axel; Werner, Jörg; Hensler, Sven; Stuhler, Jürgen; Pfau, Tilman

    2005-04-29

    We report on the generation of a Bose-Einstein condensate in a gas of chromium atoms, which have an exceptionally large magnetic dipole moment and therefore underlie anisotropic long-range interactions. The preparation of the chromium condensate requires novel cooling strategies that are adapted to its special electronic and magnetic properties. The final step to reach quantum degeneracy is forced evaporative cooling of 52Cr atoms within a crossed optical dipole trap. At a critical temperature of T(c) approximately 700 nK, we observe Bose-Einstein condensation by the appearance of a two-component velocity distribution. We are able to produce almost pure condensates with more than 50,000 condensed 52Cr atoms.

  3. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1993-01-01

    Condensation heat transfer in a horizontal rectangular duct was experimentally and analytically investigated. To prevent the dripping of condensate on the film, the experiment was conducted inside a horizontal rectangular duct with vapor condensing only on the bottom cooled plate of the duct. R-113 and FC-72 (Fluorinert Electronic Fluid developed by the 3M Company) were used as the condensing fluids. The experimental program included measurements of film thickness, local and average heat transfer coefficients, wave length, wave speed, and a study of wave initiation. The measured film thickness was used to obtain the local heat transfer coefficient. The wave initiation was studied both with condensation and with an adiabatic air-liquid flow. The test sections used in both experiments were identical.

  4. Condensing economizers: Thermal performance and particulate removal efficiencies

    SciTech Connect

    Butcher, T.A.; Litzke, Wai Lin ); Park, N. )

    1992-02-01

    Condensing economizers can be used to increase the thermal efficiency of boilers and furnaces. This project has involved a study of these specifically for application to coal-water mixture fuels although the results can be extended to other fuels. experimental studies to evaluate thermal performance and removal of particulates across indirect contract economizers have been performed. The test arrangement incorporates oil firing with the injection of flyash into the flue gas to simulate coal combustion products. Water sprays into the combustion products are used to achieve variable flue gas moisture content and a variable amount of condensation in the economizers. The economizers are tubular with flue gas on the outside of the tubes. Tube surfaces are plastic coated to prevent corrosion. The gas temperature and condensation profiles through the economizers have been predicted and overall predicted performance has been compared with test results. Mechanisms for particle removal are discussed and predicted removal efficiencies as a functions of particle diameter are presented. It is is shown that inertial impaction is the dominant mechanism and particle removal efficiencies up to 89% have been realized.

  5. Transformation of Litchi Pericarp-Derived Condensed Tannin with Aspergillus awamori

    PubMed Central

    Lin, Sen; Li, Qing; Yang, Bao; Duan, Xuewu; Zhang, Mingwei; Shi, John; Jiang, Yueming

    2016-01-01

    Condensed tannin is a ubiquitous polyphenol in plants that possesses substantial antioxidant capacity. In this study, we have investigated the polyphenol extraction recovery and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the extracted polyphenol after litchi pericarp is treated with Aspergillus awamori, Aspergillus sojae or Aspergillus oryzae. We have further explored the activity of A. awamori in the formation of condensed tannin. The treatment of A. awamori appeared to produce the highest antioxidant activity of polyphenol from litchi pericarp. Further studies suggested that the treatment of A. awamori releases the non-extractable condensed tannin from cell walls of litchi pericarp. The total extractable tannin in the litchi pericarp residue after a six-time extraction with 60% ethanol increased from 199.92 ± 14.47–318.38 ± 7.59 μg/g dry weight (DW) after the treatment of A. awamori. The ESI-TOF-MS and HPLC-MS2 analyses further revealed that treatment of A. awamori degraded B-type condensed tannin (condensed flavan-3-ol via C4–C8 linkage), but exhibited a limited capacity to degrade the condensed tannin containing A-type linkage subunits (C4–C8 coupled C2–O–C7 linkage). These results suggest that the treatment of A. awamori can significantly improve the production of condensed tannin from litchi pericarp. PMID:27420043

  6. Transformation of Litchi Pericarp-Derived Condensed Tannin with Aspergillus awamori.

    PubMed

    Lin, Sen; Li, Qing; Yang, Bao; Duan, Xuewu; Zhang, Mingwei; Shi, John; Jiang, Yueming

    2016-01-01

    Condensed tannin is a ubiquitous polyphenol in plants that possesses substantial antioxidant capacity. In this study, we have investigated the polyphenol extraction recovery and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the extracted polyphenol after litchi pericarp is treated with Aspergillus awamori, Aspergillus sojae or Aspergillus oryzae. We have further explored the activity of A. awamori in the formation of condensed tannin. The treatment of A. awamori appeared to produce the highest antioxidant activity of polyphenol from litchi pericarp. Further studies suggested that the treatment of A. awamori releases the non-extractable condensed tannin from cell walls of litchi pericarp. The total extractable tannin in the litchi pericarp residue after a six-time extraction with 60% ethanol increased from 199.92 ± 14.47-318.38 ± 7.59 μg/g dry weight (DW) after the treatment of A. awamori. The ESI-TOF-MS and HPLC-MS² analyses further revealed that treatment of A. awamori degraded B-type condensed tannin (condensed flavan-3-ol via C4-C8 linkage), but exhibited a limited capacity to degrade the condensed tannin containing A-type linkage subunits (C4-C8 coupled C2-O-C7 linkage). These results suggest that the treatment of A. awamori can significantly improve the production of condensed tannin from litchi pericarp. PMID:27420043

  7. Origin of condensation nuclei in the springtime polar stratosphere

    NASA Technical Reports Server (NTRS)

    Zhao, Jingxia; Toon, Owen B.; Turco, Richard P.

    1995-01-01

    An enhanced sulfate aerosol layer has been observed near 25 km accompanying springtime ozone depletion in the Antarctic stratosphere. We use a one-dimensional aerosol model that includes photochemistry, particle nucleation, condensational growth, coagulation, and sedimentation to study the origin of the layer. Annual cycles of sunlight, temperature, and ozone are incorporated into the model. Our results indicate that binary homogeneous nucleation leads to the formation of very small droplets of sulfuric acid and water under conditions of low temperature and production of H2SO4 following polar sunrise. Photodissociation of carbonyl sulfide (OCS) alone, however, cannot provide sufficient SO2 to create the observed condensation nuclei (CN) layer. When subsidence of SO2 from very high altitudes in the polar night vortex is incorporated into the model, the CN layer is reasonably reproduced. The model predictions, based on the subsidence in polar vortex, agree with in situ measurements of particle concentration, vertical distribution, and persistence during polar spring.

  8. Origin of Condensation Nuclei in the Springtime Polar Stratosphere

    NASA Technical Reports Server (NTRS)

    Zhao, Jingxia; Toon, Owen B.; Turco, Richard P.

    1995-01-01

    An enhanced sulfate aerosol layer has been observed near 25 km accompanying springtime ozone depletion in the Antarctic stratosphere. We use a one-dimensional aerosol model that includes photochemistry, particle nucleation, condensational growth, coagulation, and sedimentation to study the origin of the layer. Annual cycles of sunlight, temperature, and ozone are incorporated into the model. Our results indicate that binary homogeneous nucleation leads to the formation of very small droplets of sulfuric acid and water under conditions of low temperature and production of H2SO4 following polar sunrise. Photodissociation of carbonyl sulfide (OCS) alone, however, cannot provide sufficient SO2 to create the observed condensation nuclei (CN) layer. When subsidence of SO2 from very high altitudes in the polar night vortex is incorporated into the model, the CN layer is reasonably reproduced. The model predictions, based on the subsidence in polar vortex, agree with in situ measurements of particle concentration, vertical distribution, and persistence during polar spring.

  9. Intermediate reboiler and condenser arrangement for binary distillation columns

    SciTech Connect

    Agrawal, R.; Herron, D.M.

    1998-06-01

    The most thermodynamically efficient configuration for adding or removing heat from an intermediate location of an ideal binary distillation column distilling pure products is derived. The optimal policy requires that preconditioning of the feed be part of the overall decision-making process. The optimal configuration can be determined through the use of two parameters, {alpha}{sub IR} and {alpha}{sub IC}, that are solely functions of feed composition. Simple and readily usable heuristics using these parameters are developed that help instantly identify the most efficient selection among (1) totally vaporizing and returning a side-draw liquid stream from an intermediate location of the distillation column, (2) partially or totally vaporizing a portion of the given saturated liquid feed, (3) partially or totally condensing a portion of the given saturated vapor feed, and (4) totally condensing and returning a side-draw vapor stream from an intermediate location of the distillation column.

  10. Dynamics of condensation on lubricant impregnated surfaces

    NASA Astrophysics Data System (ADS)

    Anand, Sushant; Paxson, Adam; Rykaczewski, Konrad; Beysens, Daniel; Varanasi, Kripa

    2013-03-01

    Replacing the filmwise condensation mode with dropwise condensation promises large improvements in heat transfer that will lead to large cost savings in material, water consumption and decreased size of the systems. In this regards, use of superhydrophobic surfaces fabricated by texturing surfaces with nano/microstructures has been shown to lead decrease in contact line pinning of millimetric drops resulting in fast shedding. However, these useful properties are lost during condensation where droplets that nucleate within texture grow by virtue of condensation to large sized droplets while still adhering to the surface. Recently we have shown that liquid impregnated surfaces can overcome many limitations of conventional superhydrophobic surfaces during condensation. Here we discuss aspects related to condensation on lubricant surfaces, such as behavior of growing droplets. We compare the characteristics of droplets condensing on these surfaces with their behavior on conventional un-impregnated superhydrophobic surfaces and show how use of lubricant impregnated surfaces may lead to large enhancement in heat transfer and energy efficiencies.

  11. Enhancing dropwise condensation through bioinspired wettability patterning.

    PubMed

    Ghosh, Aritra; Beaini, Sara; Zhang, Bong June; Ganguly, Ranjan; Megaridis, Constantine M

    2014-11-01

    Dropwise condensation (DWC) heat transfer depends strongly on the maximum diameter (Dmax) of condensate droplets departing from the condenser surface. This study presents a facile technique implemented to gain control of Dmax in DWC within vapor/air atmospheres. We demonstrate how this approach can enhance the corresponding heat transfer rate by harnessing the capillary forces in the removal of the condensate from the surface. We examine various hydrophilic-superhydrophilic patterns, which, respectively, sustain and combine DWC and filmwise condensation on the substrate. The material system uses laser-patterned masking and chemical etching to achieve the desired wettability contrast and does not employ any hydrophobizing agent. By applying alternating straight parallel strips of hydrophilic (contact angle ∼78°) mirror-finish aluminum and superhydrophilic regions (etched aluminum) on the condensing surface, we show that the average maximum droplet size on the less-wettable domains is nearly 42% of the width of the corresponding strips. An overall improvement in the condensate collection rate, up to 19% (as compared to the control case of DWC on mirror-finish aluminum) was achieved by using an interdigitated superhydrophilic track pattern (on the mirror-finish hydrophilic surface) inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern design, particularly under higher humidity conditions in the presence of noncondensable gases (NCG), a condition that is more challenging for maintaining sustained DWC.

  12. Black holes in the ghost condensate

    SciTech Connect

    Mukohyama, Shinji

    2005-05-15

    We investigate how the ghost condensate reacts to black holes immersed in it. A ghost condensate defines a hypersurface-orthogonal congruence of timelike curves, each of which has the tangent vector u{sup {mu}}=-g{sup {mu}}{sup {nu}}{partial_derivative}{sub {nu}}{phi}. It is argued that the ghost condensate in this picture approximately corresponds to a congruence of geodesics. In other words, the ghost condensate accretes into a black hole just like a pressureless dust. Correspondingly, if the energy density of the ghost condensate at large distance is set to an extremely small value by cosmic expansion then the late-time accretion rate of the ghost condensate should be negligible. The accretion rate remains very small even if effects of higher derivative terms are taken into account, provided that the black hole is sufficiently large. It is also discussed how to reconcile the black-hole accretion with the possibility that the ghost condensate might behave like dark matter.

  13. Dispensing fuel with aspiration of condensed vapors

    SciTech Connect

    Butkovich, M.S.; Strock, D.J.

    1993-08-10

    A vapor recovery process is described, comprising the steps of: fueling a motor vehicle with gasoline by discharging gasoline into a fill opening or filler pipe of a tank of said vehicle through a fuel outlet conduit of a nozzle; emitting gasoline vapors from said tank during said fueling; substantially collecting said vapors during said fueling with a vapor return conduit of said nozzle and passing said vapors through said vapor return conduit in counter current flow relationship to said discharging gasoline in said fuel conduit; conveying said vapors from said vapor return conduit to a vapor return hose; at least some of said vapors condensing to form condensate in said vapor return hose; substantially removing said condensate from said vapor return hose during said fueling with a condensate pickup tube from said nozzle by passing said condensate through said condensate pickup tube in counter current flow relationship to said conveying vapors in said vapor return hose; sensing the presence of gasoline with a liquid sensing tube in said vapor return conduit of said nozzle between inner and outer spouts of said nozzle to detect when said tank of said vehicle is filled with said fuel conduit being within the inner spout of said nozzle; and automatically shutting off said fueling and condensate removing when said liquid sensing tube detects when said tank of said vehicle is filled and fuel enters said vapor return conduit.

  14. Boson condensation in topologically ordered quantum liquids

    NASA Astrophysics Data System (ADS)

    Neupert, Titus; He, Huan; von Keyserlingk, Curt; Sierra, Germán; Bernevig, B. Andrei

    2016-03-01

    Boson condensation in topological quantum field theories (TQFT) has been previously investigated through the formalism of Frobenius algebras and the use of vertex lifting coefficients. While general, this formalism is physically opaque and computationally arduous: analyses of TQFT condensation are practically performed on a case by case basis and for very simple theories only, mostly not using the Frobenius algebra formalism. In this paper, we provide a way of treating boson condensation that is computationally efficient. With a minimal set of physical assumptions, such as commutativity of lifting and the definition of confined particles, we can prove a number of theorems linking Boson condensation in TQFT with chiral algebra extensions, and with the factorization of completely positive matrices over Z+. We present numerically efficient ways of obtaining a condensed theory fusion algebra and S matrices; and we then use our formalism to prove several theorems for the S and T matrices of simple current condensation and of theories which upon condensation result in a low number of confined particles. We also show that our formalism easily reproduces results existent in the mathematical literature such as the noncondensability of five and ten layers of the Fibonacci TQFT.

  15. Enhancing dropwise condensation through bioinspired wettability patterning.

    PubMed

    Ghosh, Aritra; Beaini, Sara; Zhang, Bong June; Ganguly, Ranjan; Megaridis, Constantine M

    2014-11-01

    Dropwise condensation (DWC) heat transfer depends strongly on the maximum diameter (Dmax) of condensate droplets departing from the condenser surface. This study presents a facile technique implemented to gain control of Dmax in DWC within vapor/air atmospheres. We demonstrate how this approach can enhance the corresponding heat transfer rate by harnessing the capillary forces in the removal of the condensate from the surface. We examine various hydrophilic-superhydrophilic patterns, which, respectively, sustain and combine DWC and filmwise condensation on the substrate. The material system uses laser-patterned masking and chemical etching to achieve the desired wettability contrast and does not employ any hydrophobizing agent. By applying alternating straight parallel strips of hydrophilic (contact angle ∼78°) mirror-finish aluminum and superhydrophilic regions (etched aluminum) on the condensing surface, we show that the average maximum droplet size on the less-wettable domains is nearly 42% of the width of the corresponding strips. An overall improvement in the condensate collection rate, up to 19% (as compared to the control case of DWC on mirror-finish aluminum) was achieved by using an interdigitated superhydrophilic track pattern (on the mirror-finish hydrophilic surface) inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern design, particularly under higher humidity conditions in the presence of noncondensable gases (NCG), a condition that is more challenging for maintaining sustained DWC. PMID:25295388

  16. Enantioselective Multicomponent Condensation Reactions of Phenols, Aldehydes, and Boronates Catalyzed by Chiral Biphenols.

    PubMed

    Barbato, Keith S; Luan, Yi; Ramella, Daniele; Panek, James S; Schaus, Scott E

    2015-12-01

    Chiral diols and biphenols catalyze the multicomponent condensation reaction of phenols, aldehydes, and alkenyl or aryl boronates. The condensation products are formed in good yields and enantioselectivities. The reaction proceeds via an initial Friedel-Crafts alkylation of the aldehyde and phenol to yield an ortho-quinone methide that undergoes an enantioselective boronate addition. A cyclization pathway was discovered while exploring the scope of the reaction that provides access to chiral 2,4-diaryl chroman products, the core of which is a structural motif found in natural products. PMID:26576776

  17. Condensation of Carbon in Radioactive Supernova Gas

    NASA Astrophysics Data System (ADS)

    Clayton, Donald D.; Deneault, Ethan A.-N.; Meyer, Bradley S.

    2001-11-01

    The chemistry of carbon molecules leading to the formation of large carbon-bearing molecules and dust in the interior of an expanding supernova is explored and the equations governing their abundances are solved. A steady state between production and destruction is set up early and evolves adiabatically as the supernova evolves. Simple solutions for that steady state limit yield the abundance of each linear carbon molecule and its dependence on the C/O atomic ratio in the gas. Carbon dust condenses from initially gaseous C and O atoms because Compton electrons produced by the radioactivity cause dissociation of the CO molecules, which would otherwise form and limit the supply of C atoms. The resulting free C atoms enable carbon dust to grow faster by C association than its destruction by oxidation for various C/O ratios. Nucleation for graphite growth occurs when linear Cn molecules transition to ringed Cn molecules. We survey the dependence of the abundances of these molecules on the C/O ratio and on several other kinetic rate parameters. The concept of ``population control'' is significant for the maximum sizes of carbon particles grown during supernova expansion. Interpretation of presolar micrometer-sized carbon solids found in meteorites and of infrared emission from supernova is relaxed to allow O to be more abundant than C, but the maximum grain size depends upon that ratio.

  18. Dropwise condensation dynamics in humid air

    NASA Astrophysics Data System (ADS)

    Castillo Chacon, Julian Eduardo

    Dropwise condensation of atmospheric water vapor is important in multiple practical engineering applications. The roles of environmental factors and surface morphology/chemistry on the condensation dynamics need to be better understood to enable efficient water-harvesting, dehumidication, and other psychrometric processes. Systems and surfaces that promote faster condensation rates and self-shedding of condensate droplets could lead to improved mass transfer rates and higher water yields in harvesting applications. The thesis presents the design and construction of an experimental facility that allows visualization of the condensation process as a function of relative humidity. Dropwise condensation experiments are performed on a vertically oriented, hydrophobic surface at a controlled relative humidity and surface subcooling temperature. The distribution and growth of water droplets are monitored across the surface at different relative humidities (45%, 50%, 55%, and 70%) at a constant surface subcooling temperature of 15 °C below the ambient temperature. The droplet growth dynamics exhibits a strong dependency on relative humidity in the early stages during which there is a large population of small droplets on the surface and single droplet growth dominates over coalescence effects. At later stages, the dynamics of droplet growth is insensitive to relative humidity due to the dominance of coalescence effects. The overall volumetric rate of condensation on the surface is also assessed as a function of time and ambient relative humidity. Low relative humidity conditions not only slow the absolute rate of condensation, but also prolong an initial transient regime over which the condensation rate remains significantly below the steady-state value. The current state-of-the-art in dropwise condensation research indicates the need for systematic experimental investigations as a function of relative humidity. The improved understanding of the relative humidity

  19. Quasihole condensates in quantum Hall liquids

    SciTech Connect

    Suorsa, J.; Viefers, S.; Hansson, T. H.

    2011-06-15

    We develop a formalism to describe quasihole condensates in quantum Hall liquids and thereby extend the conformal field theory approach to the full hierarchy of spin-polarized Abelian states and to several classes of non-Abelian hierarchical states. Most previously proposed spin-polarized quantum Hall wave functions appear as special cases. In this paper we explain the physical motivations for the approach, and exemplify it by explicitly constructing the level-two quasihole condensate state at filling fraction 2/3, and the two level-three states at 5/13 and 5/7 which are built from combinations of quasielectron and quasihole condensates.

  20. Vortices and turbulence in trapped atomic condensates

    PubMed Central

    White, Angela C.; Anderson, Brian P.; Bagnato, Vanderlei S.

    2014-01-01

    After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880

  1. Deconfinement Phase Transition and the Quark Condensate

    SciTech Connect

    Fischer, Christian S.

    2009-07-31

    We study the dual quark condensate as a signal for the confinement-deconfinement phase transition of QCD. This order parameter for center symmetry has been defined recently by Bilgici et al. within the framework of lattice QCD. In this work we determine the ordinary and the dual quark condensate with functional methods using a formulation of the Dyson-Schwinger equations for the quark propagator on a torus. The temperature dependence of these condensates serves to investigate the interplay between the chiral and deconfinement transitions of quenched QCD.

  2. Bose-Einstein condensation of erbium.

    PubMed

    Aikawa, K; Frisch, A; Mark, M; Baier, S; Rietzler, A; Grimm, R; Ferlaino, F

    2012-05-25

    We report on the achievement of Bose-Einstein condensation of erbium atoms and on the observation of magnetic Feshbach resonances at low magnetic fields. By means of evaporative cooling in an optical dipole trap, we produce pure condensates of 168Er, containing up to 7×10(4) atoms. Feshbach spectroscopy reveals an extraordinary rich loss spectrum with six loss resonances already in a narrow magnetic-field range up to 3 G. Finally, we demonstrate the application of a low-field Feshbach resonance to produce a tunable dipolar Bose-Einstein condensate and we observe its characteristic d-wave collapse. PMID:23003221

  3. Orbital diamagnetic susceptibility in excitonic condensation phase

    NASA Astrophysics Data System (ADS)

    Sugimoto, Koudai; Ohta, Yukinori

    2016-08-01

    We study the orbital diamagnetic susceptibility in excitonic condensation phase using the mean-field approximation for a two-band model defined on a square lattice. We find that, in semiconductors, the excitonic condensation acquires a finite diamagnetic susceptibility due to spontaneous hybridization between the valence and the conduction bands, whereas in semimetals, the diamagnetic susceptibility in the normal phase is suppressed by the excitonic condensation. We also study the orbital diamagnetic and Pauli paramagnetic susceptibilities of Ta2NiSe5 using a two-dimensional three-band model and find that the calculated temperature dependence of the magnetic susceptibility is in qualitative agreement with experiment.

  4. Preoperational test report, primary ventilation condensate system

    SciTech Connect

    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.

  5. Open string decoupling and tachyon condensation

    NASA Astrophysics Data System (ADS)

    Chalmers, Gordon

    2001-06-01

    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 gs and gYM at general values of the tachyon condensate. The closed string sector is generated at the quantum level; it is also generated at the classical level perturbatively through the condensation of propagating open string modes on the D-brane degrees of freedom.

  6. Process of treating gas condensate

    SciTech Connect

    Hitzel, H.

    1984-11-06

    The sewage consists of gas condensates from coal-gasifying plants and/or coal chemical plants and contains the anions SO/sub 4/--, SCN-, NO/sub 3/-, Cl- and F- in a total of at least 2 mval/l and contains organic matter corresponding to a chemical oxygen demand of at least 1000 mg/l. The sewage is passed through a biological purification stage, and a succeeding fine purification stage. In an anion exchanger, strong anions are exchanged with hydrogen carbonate ions. The water leaving the anion exchange stage has an alkalinity of at least 2 mval/l and is passed at least in part through a cation exchanger before the water is recycled to the sewage. The water which has left the anion exchanger may be used as cooling water in a cooling tower before or after the cation exchanger. Organic acids are used for regeneration in the cation exchanger and the regeneration eluate is added to the sewage which is to be treated in the biological purification stage.

  7. Condensation Processes in Astrophysical Environments

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Rietmeijer, Frans J. M.; Hill, Hugh G. M.

    2002-01-01

    Astrophysical systems present an intriguing set of challenges for laboratory chemists. Chemistry occurs in regions considered an excellent vacuum by laboratory standards and at temperatures that would vaporize laboratory equipment. Outflows around Asymptotic Giant Branch (AGB) stars have timescales ranging from seconds to weeks depending on the distance of the region of interest from the star and, on the way significant changes in the state variables are defined. The atmospheres in normal stars may only change significantly on several billion-year timescales. Most laboratory experiments carried out to understand astrophysical processes are not done at conditions that perfectly match the natural suite of state variables or timescales appropriate for natural conditions. Experimenters must make use of simple analog experiments that place limits on the behavior of natural systems, often extrapolating to lower-pressure and/or higher-temperature environments. Nevertheless, we argue that well-conceived experiments will often provide insights into astrophysical processes that are impossible to obtain through models or observations. This is especially true for complex chemical phenomena such as the formation and metamorphism of refractory grains under a range of astrophysical conditions. Data obtained in our laboratory has been surprising in numerous ways, ranging from the composition of the condensates to the thermal evolution of their spectral properties. None of this information could have been predicted from first principals and would not have been credible even if it had.

  8. Ice-condenser aerosol tests

    SciTech Connect

    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 {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.

  9. Diquark Bose-Einstein condensation

    SciTech Connect

    Nawa, K.; Nakano, E.; Yabu, H.

    2006-08-01

    Bose-Einstein condensation of composite diquarks in quark matter (the color superconductor phase) is discussed using the quasichemical equilibrium theory at a relatively low-density region near the deconfinement phase transition, where dynamical quark-pair fluctuations are assumed to be described as bosonic degrees of freedom (diquarks). A general formulation is given for the diquark formation and particle-antiparticle pair-creation processes in the relativistic framework, and some interesting properties are shown, which are characteristic for the relativistic many-body system. Behaviors of transition temperature and phase diagram of the quark-diquark matter are generally presented in model parameter space, and their asymptotic behaviors are also discussed. As an application to the color superconductivity, the transition temperatures and the quark and diquark density profiles are calculated in case with constituent/current quarks, where the diquark is in the bound/resonant state. We obtained T{sub C}{approx}60-80 MeV for constituent quarks and T{sub C}{approx}130 MeV for current quarks at a moderate density ({rho}{sub b}{approx}3{rho}{sub 0}). The method is also developed to include interdiquark interactions into the quasichemical equilibrium theory within a mean-field approximation, and it is found that a possible repulsive diquark-diquark interaction lowers the transition temperature by {approx}50%.

  10. Magnons in a box: Condensation and Application

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Olf, Ryan; Wu, Shun; Kadau, Holger; Marti, G. Edward; Stamper-Kurn, Dan

    2016-05-01

    Ultracold gases offer us a remarkable window into the quantum world, allowing direct access to a wide range of manybody and condensed matter phenomena at convenient macroscopic length and time scales. However, producing ultracold gases at ever lower entropy, and measuring statistical properties such as temperature in these low entropy regimes, is a persistent challenge. Magnons, gapless spin excitations of spinor Bose Einstein Condensate (BEC), are expected to behave like free particles. We show that magnons can be used to cool BEC in a deep trap and serve as a thermometer to measure temperatures at extremely low entropy-per-particle. Unlike atoms trapped in a harmonic trap, trapped magnons experience a box potential due to near exact cancellation of the trapping potential by the mean-field interaction within the condensate. We observe the quasi-condensation of magnon excitations within this nature-made box.

  11. Performance investigation of finned tube condensers

    SciTech Connect

    Mathur, G.D.

    1996-12-31

    A computer program has been developed to optimize the performance of finned tube condensers. The developed program is used to predict the thermal and hydrodynamic performance of finned tube condensers. The model is based on a steady-state finite difference model. The correlations for predicting the heat transfer and pressure drop are used from the literature. In this paper, the performance of a condenser of a 2-1/2 ton residential air conditioning system (split type) is optimized. The working fluid used in this investigation is R-22. ASHRAE`s condition A [Outside 95 F DBT/75 F WBT; Inside 80 F/67 F WBT] is used in this investigation. The predicted performance of the condenser is within {+-}5% of the experimental data.

  12. Condenser design for AMTEC power conversion

    NASA Technical Reports Server (NTRS)

    Crowley, Christopher J.

    1991-01-01

    The condenser and the electrodes are the two elements of an alkali metal thermal-to-electric conversion (AMTEC) cell which most greatly affect the energy conversion performance. A condenser is described which accomplishes two critical functions in an AMTEC cell: management of the fluid under microgravity conditions and optimization of conversion efficiency. The first function is achieved via the use of a controlled surface shape, along with drainage grooves and arteries to collect the fluid. Capillary forces manage the fluid in microgravity and dominate hydrostatic effects on the ground so the device is ground-testable. The second function is achieved via a smooth film of highly reflective liquid sodium on the condensing surface, resulting in minimization of parasitic heat losses due to radiation heat transfer. Power conversion efficiencies of 25 percent to 30 percent are estimated with this condenser using present technology for the electrodes.

  13. Condensation of Chondrules: Conditions for "Fiery Rain"

    NASA Astrophysics Data System (ADS)

    Grossman, L.; Fedkin, A. V.

    2012-09-01

    Equilibrium calculations at total pressures ≥1 bar in systems with CI dust enrichments of 1000 relative to solar composition, yield condensate assemblages whose olivine and coexisting silicate liquid have compositions found in primitive chondrules.

  14. Insulate Steam Distribution and Condensate Return Lines

    SciTech Connect

    Not Available

    2006-01-01

    This revised ITP tip sheet on insulating steam distribution and condensate return lines provides how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.

  15. Recent developments in Bose-Einstein condensation

    SciTech Connect

    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.

  16. Condensation Front Migration in a Protoplanetary Nebula

    NASA Technical Reports Server (NTRS)

    Davis, Sanford S.

    2004-01-01

    Condensation front dynamics are investigated in the mid-solar nebula region. A quasi-steady model of the evolving nebula is combined with equilibrium vapor pressure curves to determine evolutionary condensation fronts for selected species. These fronts are found to migrate inwards from the far-nebula to final positions during a period of 10(exp 7) years. The physical process governing this movement is a combination of local viscous heating and luminescent heating from the central star. Two luminescent heating models are used and their effects on the ultimate radial position of the condensation front are discussed. At first the fronts move much faster than the nebular accretion velocity, but after a time the accreting gas and dust overtakes the slowing condensation front.

  17. Cold condensation of dust in the ISM.

    PubMed

    Rouillé, Gaël; Jäger, Cornelia; Krasnokutski, Serge A; Krebsz, Melinda; Henning, Thomas

    2014-01-01

    The condensation of complex silicates with pyroxene and olivine composition under conditions prevailing in molecular clouds has been experimentally studied. For this purpose, molecular species comprising refractory elements were forced to accrete on cold substrates representing the cold surfaces of surviving dust grains in the interstellar medium. The efficient formation of amorphous and homogeneous magnesium iron silicates at temperatures of about 12 K has been monitored by IR spectroscopy. The gaseous precursors of such condensation processes in the interstellar medium are formed by erosion of dust grains in supernova shock waves. In the laboratory, we have evaporated glassy silicate dust analogs and embedded the released species in neon ice matrices that have been studied spectroscopically to identify the molecular precursors of the condensing solid silicates. A sound coincidence between the 10 microm band of the interstellar silicates and the 10 microm band of the low-temperature siliceous condensates can be noted.

  18. Accretion of Ghost Condensate by Black Holes

    SciTech Connect

    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.

  19. Kaon condensation in dense stellar matter

    SciTech Connect

    Lee, Chang-Hwan; Rho, M. |

    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} {rho}/{rho}o {approx_lt} 4, in the range to allow the intriguing new phenomena predicted by Brown and Bethe to take place in compact star matter.

  20. Spatial density oscillations in trapped dipolar condensates

    SciTech Connect

    Lu, H.-Y.; Zhang, J.-N.; Qiu, R.-Z.; Yi, S.; Lu, H.; Pu, H.

    2010-08-15

    We investigated the ground-state wave function and the free expansion of a trapped dipolar condensate. We find that dipolar interaction may induce both biconcave and dumbbell density profiles in the pancake- and cigar-shaped traps, respectively. In the parameter plane of the interaction strengths, the oscillating density profile in a harmonically trapped dipolar condensate occurs only when the interaction parameters fall into certain isolated areas. The relation between the positions of these areas and the trap geometry is explored. When a box potential is used to confine the condensate, spatial density oscillation becomes a generic feature. By studying the free expansion of the condensate with an oscillating density profile, we show that the spatial density oscillation is detectable from the time-of-flight image.

  1. Condensation and Hydrolysis - An Optical Problem?

    ERIC Educational Resources Information Center

    Kellett, N. C.; Johnstone, A. H.

    1974-01-01

    Recent surveys have shown that pupils find the topics of esterification and condensation difficult. Reasons for the difficulty are not clear. Described is research designed to determine where the difficulties were visual or conceptual in origin. (RH)

  2. Bose condensates and the atom laser

    NASA Astrophysics Data System (ADS)

    Andrews, Michael R.

    In this thesis, I describe four classes of studies of cold, dilute vapors of atomic sodium. The in-situ nondestructive observation of a Bose condensate is presented in the broader context of imaging a cold polarized cloud. Two condensates were made to interfere, and a rudimentary ``atom laser'' was demonstrated. Excitations of a condensate were imaged in- situ and nondestructively, opening up the field of real- time dynamical studies. A related study attempting (unsuccessfully) to create and detect superfluid currents and vortices is discussed. Lastly, Feshbach resonances were used to modify the interactions in a Bose condensate, and the scattering length was observed to vary by over a factor of ten. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  3. Cold condensation of dust in the ISM.

    PubMed

    Rouillé, Gaël; Jäger, Cornelia; Krasnokutski, Serge A; Krebsz, Melinda; Henning, Thomas

    2014-01-01

    The condensation of complex silicates with pyroxene and olivine composition under conditions prevailing in molecular clouds has been experimentally studied. For this purpose, molecular species comprising refractory elements were forced to accrete on cold substrates representing the cold surfaces of surviving dust grains in the interstellar medium. The efficient formation of amorphous and homogeneous magnesium iron silicates at temperatures of about 12 K has been monitored by IR spectroscopy. The gaseous precursors of such condensation processes in the interstellar medium are formed by erosion of dust grains in supernova shock waves. In the laboratory, we have evaporated glassy silicate dust analogs and embedded the released species in neon ice matrices that have been studied spectroscopically to identify the molecular precursors of the condensing solid silicates. A sound coincidence between the 10 microm band of the interstellar silicates and the 10 microm band of the low-temperature siliceous condensates can be noted. PMID:25302393

  4. Experimental simulation of the condensation and metamorphism of seasonal CO2 condensates under martian conditions.

    NASA Astrophysics Data System (ADS)

    Grisolle, F.; Schmitt, B.; Beck, P.; Philippe, S.; Brissaud, O.

    2014-04-01

    An experimental set-up, CARBON-IR, has been developed in order to perform the condensation and metamorphism of CO2 condensates in various controlled martian conditions at, or out of, equilibrium. The sample texture is monitored and near-infrared reflectance spectra are recorded. We present a first set of experiments aimed to simulate the formation of compact translucent slabs by condensation of CO2 gas, the metamorphism of CO2 snow, as well as their sublimation.

  5. Asymmetric catalytic synthesis of the proposed structure of trocheliophorolide B.

    PubMed

    Trost, Barry M; Quintard, Adrien

    2012-09-01

    A concise catalytic asymmetric synthesis of the proposed structure of trocheliophorolide B is reported. The synthetic sequence notably features an asymmetric acetaldehyde alkynylation, a Ru-catalyzed alder-ene reaction, and a Zn-ProPhenol ynone aldol condensation. Comparison with the reported data suggests a misassignment of the natural product structure.

  6. Tandem ring-closing metathesis/isomerization reactions for the total synthesis of violacein.

    PubMed

    Petersen, Mette T; Nielsen, Thomas E

    2013-04-19

    A series of 5-substituted 2-pyrrolidinones was synthesized through a one-pot ruthenium alkylidene-catalyzed tandem RCM/isomerization/nucleophilic addition sequence. The intermediates resulting from RCM/isomerization showed reactivity toward electrophiles in aldol condensation reactions which provided a new entry for the total synthesis of the antileukemic natural product violacein.

  7. A Multistep Synthesis Featuring Classic Carbonyl Chemistry for the Advanced Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Duff, David B.; Abbe, Tyler G.; Goess, Brian C.

    2012-01-01

    A multistep synthesis of 5-isopropyl-1,3-cyclohexanedione is carried out from three commodity chemicals. The sequence involves an aldol condensation, Dieckmann-type annulation, ester hydrolysis, and decarboxylation. No purification is required until after the final step, at which point gravity column chromatography provides the desired product in…

  8. Probing the excitation spectrum of polariton condensates

    SciTech Connect

    Wouters, Michiel; Carusotto, Iacopo

    2009-03-15

    We propose a four-wave mixing experiment to probe the elementary excitation spectrum of a nonequilibrium Bose-Einstein condensate of exciton-polaritons under nonresonant pumping. Analytical calculations based on mean-field theory show that this method is able to reveal the characteristic negative energy feature of the Bogoliubov dispersion. Numerical simulations including the finite spatial profile of the excitation laser spot and a weak disorder confirm the practical utility of the method for realistic condensates.

  9. Proceedings: 2003 EPRI Workshop on Condensate Polishing

    SciTech Connect

    2004-02-01

    Successful condensate polishing operations maintain control of ionic and particulate impurity transport to the pressurized water reactor (PWR) steam generator and the boiling water reactor (BWR) reactor and recirculation system, thus allowing the units to operate more reliably. This report contains the work presented at EPRI's 2003 Workshop on Condensate Polishing, where 30 papers were presented on current issues, research, and utility experiences involving polishing issues at both PWR and BWR units.

  10. Condensate polishers add operating reliability and flexibility

    SciTech Connect

    Layman, C.M.; Bennett, L.L.

    2008-08-15

    Many of today's advanced steam generators favour either an all-volatile treatment or oxygenated treatment chemistry programme, both of which require strict maintenance of an ultra-pure boiler fedwater ro condensate system. Those requirements are many times at odds with the lower-quality water sources, such as greywater, available for plant makeup and cooling water. Adding a condensate polisher can be a simple, cost-effective solution. 4 figs.

  11. Dynamic simulation recalls condensate piping event

    SciTech Connect

    Farrell, R.J.; Reneberg, K.O. ); Moy, H.C. )

    1994-05-01

    This article describes how experience gained from simulating and reconstructing a condensate piping event will be used by Consolidated Edison to analyze control system problems. A cooperative effort by Con Edison and the Chemical Engineering Department at Polytechnic University used modular modeling system to investigate the probable cause of a Con Edison condensate piping event. Con Edison commissioned the work to serve as a case study for the more general problem of control systems analysis using dynamic simulation and MMS.

  12. Silicate condensation in Mira variables

    NASA Astrophysics Data System (ADS)

    Gail, Hans-Peter; Scholz, Michael; Pucci, Annemarie

    2016-06-01

    Context. The formation of dust in winds of cool and highly evolved stars and the rate of injection of dust into the interstellar medium is not yet completely understood, despite the importance of the process for the evolution of stars and galaxies. This holds in particular for oxygen-rich stars, where it is still not known which process is responsible for the formation of the necessary seed particles of their silicate dust. Aims: We study whether the condensation of silicate dust in Mira envelopes could be caused by cluster formation by the abundant SiO molecules. Methods: We solve the dust nucleation and growth equations in the co-moving frame of a fixed mass element for a simplified model of the pulsational motions of matter in the outer layers of a Mira variable, which is guided by a numerical model for Mira pulsations. It is assumed that seed particles form through the clustering of SiO. The calculation of the nucleation rate is based on published experimental data. The quantity of dust formed is calculated via a moment method and the calculation of radiation pressure on dusty gas is based on a dirty silicate model. Results: Dust nucleation occurs in the model at the upper culmination of the trajectory of a gas parcel where it stays for a considerable time at low temperatures. Subsequent dust growth occurs during the descending part of the motion and continues after the next shock reversed motion. It is found that sufficient dust forms that radiation pressure exceeds the gravitational pull of the stars such that the mass element is finally driven out of the star. Conclusions: Nucleation of dust particles by clustering of the abundant SiO molecules could be the mechanism that triggers silicate dust formation in Miras.

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

    SciTech Connect

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

    2012-07-01

    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)

  14. Condensation of the air-steam mixture in a vertical tube condenser

    NASA Astrophysics Data System (ADS)

    Havlík, Jan; Dlouhý, Tomáš

    2016-03-01

    This paper deals with the condensation of water vapour in the presence of non-condensable air. Experimental and theoretical solutions of this problem are presented here. A heat exchanger for the condensation of industrial waste steam containing infiltrated air was designed. The condenser consists of a bundle of vertical tubes in which the steam condenses as it flows downwards with cooling water flowing outside the tubes in the opposite direction. Experiments with pure steam and with mixtures of steam with added air were carried out to find the dependence of the condensation heat transfer coefficient (HTC) on the air concentration in the steam mixture. The experimental results were compared with the theoretical formulas describing the cases. The theoretical determination of the HTC is based on the Nusselt model of steam condensation on a vertical wall, where the analogy of heat and mass transfer is used to take into account the behaviour of air in a steam mixture during the condensation process. The resulting dependencies obtained from the experiments and obtained from the theoretical model have similar results. The significant decrease in the condensation HTC, which begins at very low air concentrations in a steam mixture, was confirmed.

  15. Intrinsic bioremediation of gas condensate hydrocarbons - field and laboratory investigations

    SciTech Connect

    Barker, G.W.; Raterman, K.T.; Fisher, J.B.; Corgan, J.M.

    1995-12-31

    Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July, 1993, to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate endpoint to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways including aerobic oxidation, Fe(III) reduction and sulfate reduction. In laboratory experiments the addition of gas condensate hydrocarbons to saturated soil from the gas production site stimulated sulfate reduction under anaerobic and oxygen-limiting conditions, and nitrate and Fe(III) reduction under oxygen-limiting conditions, compared to biotic controls that lacked hydrocarbon and sterile controls. The sulfate reduction corresponded to a reduction in the amount of toluene relative to other hydrocarbons. These results confirmed that subsurface soils at the gas production site have the potential for intrinsic bioremediation of hydrocarbons.

  16. Wettability Patterning for Enhanced Dropwise Condensation

    NASA Astrophysics Data System (ADS)

    Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

    2014-11-01

    Dropwise condensation (DwC), in order to be sustainable, requires removal of the condensate droplets. This removal is frequently facilitated by gravity. The rate of DwC heat transfer depends strongly on the maximum departing droplet diameter. Based on wettability patterning, we present a facile technique designed to control the maximum droplet size in DwC within vapor/air atmospheres, and demonstrate how this approach can be used to enhance the corresponding heat transfer rate. We examine various hydrophilic-superhydrophilic patterns, which, respectively sustain DwC and filmwise (FwC) condensation on the substrate. The fabrication method does notemploy any hydrophobizing agent. By juxtaposing parallel lines of hydrophilic (CA ~ 78°) and superhydrophilic (CA ~ 0°) regions on the condensing surface, we create alternating domains of DwC and FwC. The average droplet size on the DwC domain is reduced by ~ 60% compared to the theoretical maximum, which corresponds to the line width. We compare heat transfer rate between unpatternend DwC surfaces and patterned DwC surfaces. Even after sacrificing 40% of condensing area, we achieve up to 20% improvement in condensate collection rate using an interdigitated superhydrophilic pattern, inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern, particularly under higher vapor loadings in an air/vapor ambient atmosphere. NSF STTR Grant 1331817 via NBD Nano.

  17. Numerical simulation of condensation on structured surfaces.

    PubMed

    Fu, Xiaowu; Yao, Zhaohui; Hao, Pengfei

    2014-11-25

    Condensation of liquid droplets on solid surfaces happens widely in nature and industrial processes. This phase-change phenomenon has great effect on the performance of some microfluidic devices. On the basis of micro- and nanotechnology, superhydrophobic structured surfaces can be well-fabricated. In this work, the nucleating and growth of droplets on different structured surfaces are investigated numerically. The dynamic behavior of droplets during the condensation is simulated by the multiphase lattice Boltzmann method (LBM), which has the ability to incorporate the microscopic interactions, including fluid-fluid interaction and fluid-surface interaction. The results by the LBM show that, besides the chemical properties of surfaces, the topography of structures on solid surfaces influences the condensation process. For superhydrophobic surfaces, the spacing and height of microridges have significant influence on the nucleation sites. This mechanism provides an effective way for prevention of wetting on surfaces in engineering applications. Moreover, it suggests a way to prevent ice formation on surfaces caused by the condensation of subcooled water. For hydrophilic surfaces, however, microstructures may be submerged by the liquid films adhering to the surfaces. In this case, microstructures will fail to control the condensation process. Our research provides an optimized way for designing surfaces for condensation in engineering systems.

  18. SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES

    SciTech Connect

    Nakamura, Fumitaka; Kawabe, Ryohei; Takakuwa, Shigehisa

    2012-10-20

    We present combined Submillimeter Array and single-dish images of the (sub)millimeter dust continuum emission toward two prestellar cores, SM1 and B2-N5, in the nearest star-cluster-forming region, {rho} Ophiuchus. Our combined images indicate that SM1 and B2-N5 consist of three and four condensations, respectively, with masses of 10{sup -2}-10{sup -1} M{sub Sun} and sizes of a few hundred AU. The individual condensations have mean densities of 10{sup 8}-10{sup 9} cm{sup -3} and the masses are comparable to or larger than the critical Bonner-Ebert mass, indicating that self-gravity plays an important role in the dynamical evolution of the condensations. The coalescence timescale of these condensations is estimated to be about 10{sup 4} yr, which is comparable to the local gravitational collapse timescale, suggesting that merging of the condensations, instead of accretion, plays an essential role in the star formation process. These results challenge the standard theory of star formation, where a single, rather featureless, prestellar core collapses to form at most a couple of condensations, each of which potentially evolves into a protostar that is surrounded by a rotating disk where planets are created.

  19. Numerical simulation of condensation on structured surfaces.

    PubMed

    Fu, Xiaowu; Yao, Zhaohui; Hao, Pengfei

    2014-11-25

    Condensation of liquid droplets on solid surfaces happens widely in nature and industrial processes. This phase-change phenomenon has great effect on the performance of some microfluidic devices. On the basis of micro- and nanotechnology, superhydrophobic structured surfaces can be well-fabricated. In this work, the nucleating and growth of droplets on different structured surfaces are investigated numerically. The dynamic behavior of droplets during the condensation is simulated by the multiphase lattice Boltzmann method (LBM), which has the ability to incorporate the microscopic interactions, including fluid-fluid interaction and fluid-surface interaction. The results by the LBM show that, besides the chemical properties of surfaces, the topography of structures on solid surfaces influences the condensation process. For superhydrophobic surfaces, the spacing and height of microridges have significant influence on the nucleation sites. This mechanism provides an effective way for prevention of wetting on surfaces in engineering applications. Moreover, it suggests a way to prevent ice formation on surfaces caused by the condensation of subcooled water. For hydrophilic surfaces, however, microstructures may be submerged by the liquid films adhering to the surfaces. In this case, microstructures will fail to control the condensation process. Our research provides an optimized way for designing surfaces for condensation in engineering systems. PMID:25347594

  20. Infinite statistics condensate as a model of dark matter

    SciTech Connect

    Ebadi, Zahra; Mirza, Behrouz; Mohammadzadeh, Hosein E-mail: b.mirza@cc.iut.ac.ir

    2013-11-01

    In some models, dark matter is considered as a condensate bosonic system. In this paper, we prove that condensation is also possible for particles that obey infinite statistics and derive the critical condensation temperature. We argue that a condensed state of a gas of very weakly interacting particles obeying infinite statistics could be considered as a consistent model of dark matter.

  1. 46 CFR 56.50-35 - Condensate pumps.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Condensate pumps. 56.50-35 Section 56.50-35 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-35 Condensate pumps. Two means shall be provided for discharging the condensate from the main condenser, one of which shall be...

  2. 46 CFR 56.50-35 - Condensate pumps.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Condensate pumps. 56.50-35 Section 56.50-35 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-35 Condensate pumps. Two means shall be provided for discharging the condensate from the main condenser, one of which shall be...

  3. 46 CFR 56.50-35 - Condensate pumps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Condensate pumps. 56.50-35 Section 56.50-35 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-35 Condensate pumps. Two means shall be provided for discharging the condensate from the main condenser, one of which shall be...

  4. 46 CFR 56.50-35 - Condensate pumps.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Condensate pumps. 56.50-35 Section 56.50-35 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-35 Condensate pumps. Two means shall be provided for discharging the condensate from the main condenser, one of which shall be...

  5. Condensation and Evaporation of Solar System Materials

    NASA Astrophysics Data System (ADS)

    Davis, A. M.; Richter, F. M.

    2003-12-01

    It is widely believed that the materials making up the solar system were derived from a nebular gas and dust cloud that went through an early high-temperature stage during which virtually all of the material was in the gas phase. At one time, it was thought that the entire inner solar nebula was hot, but it is now believed that most material was processed through regions where high temperatures were achieved. Certainly some material, such as presolar grains (cf., Mendybaev et al., 2002a), has never been exposed to high temperatures. As the system cooled, solids and perhaps liquids began to condense, but at some point the partially condensed materials became isolated from the remaining gas. Various lines of evidence support this view. At the largest scale, there is the observation that the Earth, Moon, Mars, and all chondritic meteorites except for the CI chondrites are depleted to varying degrees in the abundances of moderately volatile elements relative to bulk solar system composition. The CI chondrites reflect the bulk composition of the solar system for all but hydrogen, carbon, nitrogen, oxygen, and the rare gases, the most volatile elements (see Chapter 1.03; Palme et al., 1988; McDonough and Sun, 1995; Humayun and Cassen, 2000). The depletions in moderately volatile elements are, to a significant degree, correlated with condensation temperature, suggesting progressive removal of gas as condensation proceeded ( Cassen, 1996). Additional observations that can be explained by partial condensation are that various particularly primitive components of meteorites (e.g., calcium-, aluminum-rich refractory inclusions, and certain metal grains) have mineralogy and/or details of their chemical composition that are remarkably similar to what is calculated for equilibrium condensates from a solar composition gas. For example, the calcium-, aluminum-rich inclusions (CAIs) in chondritic meteorites have compositions very similar to that calculated for the first 5% of total

  6. Dropwise condensation on superhydrophobic surfaces with two-tier roughness

    NASA Astrophysics Data System (ADS)

    Chen, Chuan-Hua; Cai, Qingjun; Tsai, Chialun; Chen, Chung-Lung; Xiong, Guangyong; Yu, Ying; Ren, Zhifeng

    2007-04-01

    Dropwise condensation can enhance heat transfer by an order of magnitude compared to film condensation. Superhydrophobicity appears ideal to promote continued dropwise condensation which requires rapid removal of condensate drops; however, such promotion has not been reported on engineered surfaces. This letter reports continuous dropwise condensation on a superhydrophobic surface with short carbon nanotubes deposited on micromachined posts, a two-tier texture mimicking lotus leaves. On such micro-/nanostructured surfaces, the condensate drops prefer the Cassie state which is thermodynamically more stable than the Wenzel state. With a hexadecanethiol coating, superhydrophobicity is retained during and after condensation and rapid drop removal is enabled.

  7. Improved Cloud Condensation Nucleus Spectrometer

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    2010-01-01

    An improved thermal-gradient cloud condensation nucleus spectrometer (CCNS) has been designed to provide several enhancements over prior thermal- gradient counters, including fast response and high-sensitivity detection covering a wide range of supersaturations. CCNSs are used in laboratory research on the relationships among aerosols, supersaturation of air, and the formation of clouds. The operational characteristics of prior counters are such that it takes long times to determine aerosol critical supersaturations. Hence, there is a need for a CCNS capable of rapid scanning through a wide range of supersaturations. The present improved CCNS satisfies this need. The improved thermal-gradient CCNS (see Figure 1) incorporates the following notable features: a) The main chamber is bounded on the top and bottom by parallel thick copper plates, which are joined by a thermally conductive vertical wall on one side and a thermally nonconductive wall on the opposite side. b) To establish a temperature gradient needed to establish a supersaturation gradient, water at two different regulated temperatures is pumped through tubes along the edges of the copper plates at the thermally-nonconductive-wall side. Figure 2 presents an example of temperature and supersaturation gradients for one combination of regulated temperatures at the thermally-nonconductive-wall edges of the copper plates. c) To enable measurement of the temperature gradient, ten thermocouples are cemented to the external surfaces of the copper plates (five on the top plate and five on the bottom plate), spaced at equal intervals along the width axis of the main chamber near the outlet end. d) Pieces of filter paper or cotton felt are cemented onto the interior surfaces of the copper plates and, prior to each experimental run, are saturated with water to establish a supersaturation field inside the main chamber. e) A flow of monodisperse aerosol and a dilution flow of humid air are introduced into the main

  8. Buckling condensation in constrained growth

    NASA Astrophysics Data System (ADS)

    Dervaux, Julien; Ben Amar, Martine

    2011-03-01

    The multiple complexities inherent to living objects have motivated the search for abiotic substitutes, able to mimic some of their relevant physical properties. Hydrogels provide a highly monitorable counterpart and have thus found many applications in medicine and bioengineering. Recently, it has been recognized that their ability to swell could be used to unravel some of the universal physical processes at work during biological growth. However, it is yet unknown how the microscopic distinctions between swelling and biological growth affect macroscopic changes (shape, stresses) induced by volume variations. To answer this question, we focus on a clinically motivated example of growth. Some solid tumors such as melanoma or glioblastoma undergo a shape transition during their evolution. This bifurcation appears when growth is confined at the periphery of the tumor and is concomitant with the transition from the avascular to the vascular stage of the tumor evolution. To model this phenomenon, we consider in this paper the deformation of an elastic ring enclosing a core of different stiffness. When the volume of the outer ring increases, the system develops a periodic instability. We consider two possible descriptions of the volume variation process: either by imposing a homogeneous volumetric strain (biological growth) or through migration of solvent molecules inside a solid network (swelling). For thin rings, both theories are in qualitative agreement. When the interior is soft, we predict the emergence of a large wavelength buckling. Upon increasing the stiffness of the inner disc, the wavelength of the instability decreases until a condensation of the buckles occurs at the free boundary. This short wavelength pattern is independent of the stiffness of the disc and is only limited by the presence of surface tension. For thicker rings, two scenarios emerge. When a volumetric strain is prescribed, compressive stresses accumulate in the vicinity of the core and the

  9. Mitotic chromosome condensation in vertebrates

    SciTech Connect

    Vagnarelli, Paola

    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 of

  10. Enhanced tubes for steam condensers. Volume 1, Summary of condensation and fouling; Volume 2, Detailed study of steam condensation

    SciTech Connect

    Webb, R.L.; Chamra, L.; Jaber, H.

    1992-02-01

    Electric utility steam condensers typically use plain tubes made of titanium, stainless steel, or copper alloys. Approximately two-thirds of the total thermal resistance is on the water side of the plain tube. This program seeks to conceive and develop a tube geometry that has special enhancement geometries on the tube (water) side and the steam (shell) side. This ``enhanced`` tube geometry, will provide increased heat transfer coefficients. The enhanced tubes will allow the steam to condense at a lower temperature. The reduced condensing temperature will reduce the turbine heat rate, and increase the plant peak load capability. Water side fouling and fouling control is a very important consideration affecting the choice of the tube side enhancement. Hence, we have consciously considered fouling potential in our selection of the tube side surface geometry. Using appropriate correlations and theoretical models, we have designed condensation and water side surface geometries that will provide high performance and be cleanable using sponge ball cleaning. Commercial tube manufacturers have made the required tube geometries for test purposes. The heat transfer test program includes measurement of the condensation and water side heat transfer coefficients. Fouling tests are being run to measure the waterside fouling resistance, and to the test the ability of the sponge ball cleaning system to clean the tubes.

  11. Bose-Einstein Condensation of Dark Matter Axions

    SciTech Connect

    Sikivie, P.; Yang, Q.

    2009-09-11

    We show that cold dark matter axions thermalize and form a Bose-Einstein condensate (BEC). We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the nonlinear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.

  12. Bose-Einstein condensation of dark matter axions.

    PubMed

    Sikivie, P; Yang, Q

    2009-09-11

    We show that cold dark matter axions thermalize and form a Bose-Einstein condensate (BEC). We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the nonlinear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.

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

    SciTech Connect

    Not Available

    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.

  14. Deepak Condenser Model (DeCoM)

    NASA Technical Reports Server (NTRS)

    Patel, Deepak

    2013-01-01

    Development of the DeCoM comes from the requirement of analyzing the performance of a condenser. A component of a loop heat pipe (LHP), the condenser, is interfaced with the radiator in order to reject heat. DeCoM simulates the condenser, with certain input parameters. Systems Improved Numerical Differencing Analyzer (SINDA), a thermal analysis software, calculates the adjoining component temperatures, based on the DeCoM parameters and interface temperatures to the radiator. Application of DeCoM is (at the time of this reporting) restricted to small-scale analysis, without the need for in-depth LHP component integrations. To efficiently develop a model to simulate the LHP condenser, DeCoM was developed to meet this purpose with least complexity. DeCoM is a single-condenser, single-pass simulator for analyzing its behavior. The analysis is done based on the interactions between condenser fluid, the wall, and the interface between the wall and the radiator. DeCoM is based on conservation of energy, two-phase equations, and flow equations. For two-phase, the Lockhart- Martinelli correlation has been used in order to calculate the convection value between fluid and wall. Software such as SINDA (for thermal analysis analysis) and Thermal Desktop (for modeling) are required. DeCoM also includes the ability to implement a condenser into a thermal model with the capability of understanding the code process and being edited to user-specific needs. DeCoM requires no license, and is an open-source code. Advantages to DeCoM include time dependency, reliability, and the ability for the user to view the code process and edit to their needs.

  15. Bose-Einstein condensation of sodium atoms

    NASA Astrophysics Data System (ADS)

    Mewes, Marc-Oliver

    1997-10-01

    Bose-Einstein Condensation in an ultracold gas of neutral sodium atoms has been observed and studied. This was achieved utilizing a combination of laser cooling techniques, magnetic trapping and evaporative cooling. A novel tightly confining dc magnetic trap was developed and demonstrated. This trap combines tight confinement with excellent optical access. Evaporative cooling in this trap produced Bose condensates of 5× 106 atoms, a tenfold improvement over previous results. The Bose-Einstein phase transition was studied and characterized by mapping out the condensed fraction as a function of temperature across the transition point. The characteristic mean-field interaction of particles in the condensate was investigated. Collective excitations of a dilute Bose condensate have been observed. These excitations are analogous to phonons in superfluid helium. The frequencies of the lowest modes were studied for a temperature close to 0 K and compared with theoretical predictions based on mean-field theory. The characteristic damping of one of the modes was measured and compared to damping of 'sound waves' in an ultra-cold gas above the Bose-Einstein transition. We have also demonstrated an output coupler for Bose condensed atoms in a magnetic trap. With short rf pulses Bose condensates were put into a superposition of trapped and untrapped hyperfine states. By varying the rf amplitude we could adjust the fraction of outcoupled atoms between 0 and 100%. This source produces pulses of coherent atoms and can be regarded as a pulsed 'atom laser'. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  16. Efficient use of an intermediate reboiler or condenser in a binary distillation

    SciTech Connect

    Agrawal, R.; Herron, D.M.

    1998-06-01

    The impact of an intermediate reboiler or condenser on the distillation of ideal binary mixtures into pure product streams is studied using a simplified model. The advantage of heuristics derived from this study is that they can quickly tell a process engineer if an intermediate reboiler or condenser is going to be effective in improving the efficiency and, of the two options, which one would be more effective. The heuristics simply states that if the actual fraction of liquid in a given feed is less than that with the maximum thermodynamic efficiency for distillation with no intermediate reboiler or condenser, then an intermediate condenser not only substantially improves the thermodynamic efficiency but is also more effective than an intermediate reboiler. An analogous heuristics exists for the intermediate reboiler when the fraction of liquid in the feed is greater than the optimum. Quick identification of cases that can achieve a substantial improvement in efficiency provides an incentive to search for the proper utilities needed for the intermediate reboiler or condenser. When relatively pure feed streams (concentration of either component greater than 90%) are distilled, the extremely low efficiencies of distillation can be remarkably improved by using an intermediate reboiler or condenser.

  17. Condensation of refractory metals in asymptotic giant branch and other stellar environments

    SciTech Connect

    Schwander, D.; Berg, T.; Schönhense, G.; Ott, U.

    2014-09-20

    The condensation of material from a gas of solar composition has been extensively studied, but less so condensation in the environment of evolved stars, which has been mainly restricted to major compounds and some specific element groups such as the Rare Earth elements. Also of interest, however, are refractory metals like Mo, Ru, Os, W, Ir, and Pt, which may condense to form refractory metal nuggets (RMNs) like the ones that have been found in association with presolar graphite. We have performed calculations describing the condensation of these elements in the outflows of s-process enriched AGB stars as well as from gas enriched in r-process products. While in carbon-rich environments (C > O), the formation of carbides is expected to consume W, Mo, and V (Lodders and Fegley), the condensation sequence for the other refractory metals under these conditions does not significantly differ from the case of a cooling gas of solar composition. The composition in detail, however, is significantly different due to the completely different source composition. Condensation from an r-process enriched source differs less from the solar case. Elemental abundance ratios of the refractory metals can serve as a guide for finding candidate presolar grains among the RMNs in primitive meteorites—most of which have a solar system origin—for confirmation by isotopic analysis. We apply our calculations to the case of the four RMNs found by Croat et al., which may very well be presolar.

  18. Effect of Non-Condensable Gas Mass Fraction on Condensation Heat Transfer for Water-Ethanol Vapor Mixture

    NASA Astrophysics Data System (ADS)

    Wang, Shixue; Utaka, Yoshio

    The condensation heat transfer characteristic curves for a ternary vapor mixture of water, ethanol and air (or nitrogen) under several ethanol concentrations and relatively low concentrations of air (or nitrogen) were measured. The effect of non-condensable gas on several different domains in the condensation curves was discussed. The effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable; whereas that in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, variations due to changes in non-condensable gas concentration of several characteristic points representing the curves were discussed.

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

    EPA Science Inventory

    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...

  20. Non-destructive Measurement of Total Carotenoid Content in Processed Tomato Products: Infrared Lock-In Thermography, Near-Infrared Spectroscopy/Chemometrics, and Condensed Phase Laser-Based Photoacoustics—Pilot Study

    NASA Astrophysics Data System (ADS)

    Bicanic, D.; Streza, M.; Dóka, O.; Valinger, D.; Luterotti, S.; Ajtony, Zs.; Kurtanjek, Z.; Dadarlat, D.

    2015-09-01

    Carotenes found in a diversity of fruits and vegetables are among important natural antioxidants. In a study described in this paper, the total carotenoid content (TCC) in seven different products derived from thermally processed tomatoes was determined using laser photoacoustic spectroscopy (LPAS), infrared lock-in thermography (IRLIT), and near-infrared spectroscopy (NIRS) combined with chemometrics. Results were verified versus data obtained by traditional VIS spectrophotometry (SP) that served as a reference technique. Unlike SP, the IRLIT, NIRS, and LPAS require a minimum of sample preparation which enables practically direct quantification of the TCC.

  1. Simulation Prediction of Transient Dropwise Condensation

    NASA Astrophysics Data System (ADS)

    Macner, Ashley; Daniel, Susan; Steen, Paul

    2014-11-01

    In order to design effective surfaces for large-scale dropwise condensation, an understanding of how surface functionalization affects drop growth and coalescence is needed. The long term technological goal is a set of design conditions to help NASA achieve maximum heat transfer rates of waste heat generated from electronics and habitable environments under microgravity conditions. Prediction of condenser surface heat transfer performance requires accurate simulation and modeling of the evolution of populations of drops in time. At shorter times, drops are primarily isolated and grow mainly by condensation onto the liquid-gas interface. At longer times, drops grow mainly by coalescence with neighbors. Simulation of dropwise condensation on a neutrally wetting surface and comparison with our previous experimental results is reported. A steady-state single drop conduction model is empirically fitted to determine a temperature profile that captures the drop size evolution. The simulation accurately predicts the continuous time evolution of number-density of drops, drop-size distributions, total condensate volume, fractional coverage, and median drop-size for both transient and steady states, all with no free parameters. This work was supported by a NASA Office of the Chief Technologist's Space Technology Research Fellowship.

  2. Why double-stranded RNA resists condensation.

    PubMed

    Tolokh, Igor S; Pabit, Suzette A; Katz, Andrea M; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan; Pollack, Lois; Onufriev, Alexey V

    2014-01-01

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to inter-DNA attraction and eventual condensation. Surprisingly, the condensation is suppressed in double-stranded RNA, which carries the same negative charge as DNA, but assumes a different double helical form. Here, we combine experiment and atomistic simulations to propose a mechanism that explains the variations in condensation of short (25 base-pairs) nucleic acid (NA) duplexes, from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA. Circular dichroism measurements suggest that duplex helical geometry is not the fundamental property that ultimately determines the observed differences in condensation. Instead, these differences are governed by the spatial variation of cobalt hexammine (CoHex) binding to NA. There are two major NA-CoHex binding modes--internal and external--distinguished by the proximity of bound CoHex to the helical axis. We find a significant difference, up to 5-fold, in the fraction of ions bound to the external surfaces of the different NA constructs studied. NA condensation propensity is determined by the fraction of CoHex ions in the external binding mode.

  3. The NSF Condensed Matter Physics Program

    NASA Astrophysics Data System (ADS)

    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.

  4. Rotating trapped Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Fetter, A. L.

    2008-01-01

    Trapped Bose-Einstein condensates (BECs) differ considerably from the standard textbook example of a uniform Bose gas. In an isotropic harmonic potential V( r) = ½ Mω2 r 2, the single-particle ground state introduces a new intrinsic scale of length [the ground-state size d = √ ℏ/( Mω)] and energy [the ground-state energy E 0 = frac{3} {2} ℏω]. When the trap rotates at a low angular velocity, the behavior of a single vortex illustrates the crucial role of discrete quantized vorticity. For more rapid rotation, the condensate contains a vortex array. The resulting centrifugal forces expand the condensate radially and shrink it axially; thus, the condensate becomes effectively two dimensional. If the external rotation speed approaches the frequency of the radial harmonic confining potential, the condensate enters the "lowest-Landau-level" regime, and a simple description again becomes possible. Eventually, the system is predicted to make a quantum phase transition to a highly correlated state analogous to the fractional quantum Hall states of electrons in a strong magnetic field.

  5. Condenser biofouling control with ferrate(VI)

    SciTech Connect

    Fagan, J.; Waite, T.D.

    1982-01-01

    Biofouling is caused by bacterial growth on the walls of the condenser. The cells become attached, increase in number, secrete extracellular material and create a slime. The organic deposits attract additional deposits of organic and inorganic material. Also increases in heat transfer resistance result in less efficient condensation and therefore less backpressure to the turbine. With less vacuum in the system, the steam passes more slowly through the turbine, generating less electricity, and resulting in greater fuel consumption per unit of electrical energy produced. To reduce this extra energy generation cost, condensers must be treated to reduce biofouling. The objective of this study was to investigate the possible use of iron(VI) ferrate as an alternative to chlorine in controlling biofilm formation. The effectiveness of ferrate in controlling film growth was investigated using a model laboratory condenser system. Potassium ferrate was used in this study. Results indicate that ferrate(VI) ion appears to be an effective antifoulant. Short contact times are required for ferrate concentrations of 10/sup -5/M to maintain condenser cleanliness. (DMC)

  6. Laser Isotope Separation Employing Condensation Repression

    SciTech Connect

    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.

  7. A biocompatible condensation reaction for controlled assembly of nanostructures in living cells

    NASA Astrophysics Data System (ADS)

    Liang, Gaolin; Ren, Hongjun; Rao, Jianghong

    2010-01-01

    Through controlled synthesis and molecular assembly, biological systems are able to organize molecules into supramolecular structures that carry out sophisticated processes. Although chemists have reported a few examples of supramolecular assembly in water, the controlled covalent synthesis of large molecules and structures in vivo has remained challenging. Here we report a condensation reaction between 1,2-aminothiol and 2-cyanobenzothiazole that occurs in vitro and in living cells under the control of either pH, disulfide reduction or enzymatic cleavage. In vitro, the size and shape of the condensation products, and the nanostructures subsequently assembled, were different in each case and could thus be controlled by tuning the structure of the monomers. Direct imaging of the products obtained in the cells revealed their locations-near the Golgi bodies under enzymatic cleavage control-demonstrating the feasibility of a controlled and localized reaction in living cells. This intracellular condensation process enabled the imaging of the proteolytic activity of furin.

  8. Condensation heat transfer coefficient versus wettability

    NASA Astrophysics Data System (ADS)

    Roudgar, M.; De Coninck, J.

    2015-05-01

    In this paper we show how condensation on substrates can induce wetting behavior that is quite different from that of deposited or impinging drops. We describe surfaces with the same wettability in ambient conditions presenting different wetting behavior and growth of droplets in condensation. The experimental results show a rapid spread of droplets and formation of the film on the copper surface, while droplets on SU-8 surface remains on the regular shape while they grow within the time, without coalescence, as observed for Cu. Although the heat conductivity of SU-8 is much lower, due to a difference in wetting behavior, the heat transfer coefficient (h) is higher for dropwise condensation on Cu with a thin layer of SU-8 than filmwise on the bare copper.

  9. DROPWISE CONDENSATION ON MICRO- AND NANOSTRUCTURED SURFACES

    SciTech Connect

    Enright, R; Miljkovic, N; Alvarado, JL; Kim, K; Rose, JW

    2014-07-23

    In this review we cover recent developments in the area of surface-enhanced dropwise condensation against the background of earlier work. The development of fabrication techniques to create surface structures at the micro-and nanoscale using both bottom-up and top-down approaches has led to increased study of complex interfacial phenomena. In the heat transfer community, researchers have been extensively exploring the use of advanced surface structuring techniques to enhance phase-change heat transfer processes. In particular, the field of vapor-to-liquid condensation and especially that of water condensation has experienced a renaissance due to the promise of further optimizing this process at the micro-and nanoscale by exploiting advances in surface engineering developed over the last several decades.

  10. Preoperational test report, recirculation condenser cooling systems

    SciTech Connect

    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.

  11. Condensing heat exchangers for maximum boiler efficiency

    SciTech Connect

    Johnson, D.W.; DiVitto, J.G.; Rakocy, M.E.

    1994-12-31

    Until now, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense out, rapid deterioration, due to acid corrosion, of the outlet duct and stack would result. With the development of the condensing heat exchanger, boiler efficiency can now exceed 90%. Approximately 1% gain in boiler efficiency can be expected for every 40 F (4.5 C) reduction in flue gas stack temperature. In the CHX{reg_sign} condensing heat exchanger, all gas wetted surfaces are covered with DuPont Teflon{reg_sign}. The Teflon covered heat exchanger surfaces are impervious to all acids normally resulting from the combustion of fossil fuels. This allows the flue gas to be cooled to below the water vapor dew point with no subsequent corrosion of the heat exchanger surfaces.

  12. An Aerosol Condensation Model for Sulfur Trioxide

    SciTech Connect

    Grant, K E

    2008-02-07

    This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur trioxide

  13. Why double-stranded RNA resists condensation

    SciTech Connect

    Tolokh, Igor S.; Pabit, Suzette; Katz, Andrea M.; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan A.; Pollack, Lois; Onufriev, Alexey

    2014-09-15

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to attraction between the negatively charged helices and eventually to condensation. Surprisingly, this effect is suppressed in double-stranded RNA, which carries the same charge as the DNA, but assumes a different double helical form. However, additional characterization of short (25 base-pairs) nucleic acid (NA) duplex structures by circular dichroism shows that measured differences in condensation are not solely determined by duplex helical geometry. Here we combine experiment, theory, and atomistic simulations to propose a mechanism that connects the observed variations in condensation of short NA duplexes with the spatial variation of cobalt hexammine (CoHex) binding at the NA duplex surface. The atomistic picture that emerged showed that CoHex distributions around the NA reveals two major NA-CoHex binding modes -- internal and external -- distinguished by the proximity of bound CoHex to the helical axis. Decreasing trends in experimentally observed condensation propensity of the four studied NA duplexes (from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA) are explained by the progressive decrease of a single quantity: the fraction of CoHex ions in the external binding mode. Thus, while NA condensation depends on a complex interplay between various structural and sequence features, our coupled experimental and theoretical results suggest a new model in which a single parameter connects the NA condensation propensity with geometry and sequence dependence of CoHex binding.

  14. Condenser optic with sacrificial reflective surface

    DOEpatents

    Tichenor, Daniel A.; Kubiak, Glenn D.; Lee, Sung Hun

    2007-07-03

    Employing collector optics that has a sacrificial reflective surface can significantly prolong the useful life of the collector optics and the overall performance of the condenser in which the collector optics are incorporated. The collector optics is normally subject to erosion by debris from laser plasma source of radiation. The presence of an upper sacrificial reflective surface over the underlying reflective surface effectively increases the life of the optics while relaxing the constraints on the radiation source. Spatial and temporally varying reflectivity that results from the use of the sacrificial reflective surface can be accommodated by proper condenser design.

  15. Condenser optic with sacrificial reflective surface

    DOEpatents

    Tichenor, Daniel A.; Kubiak, Glenn D.; Lee, Sang Hun

    2006-07-25

    Employing collector optics that have a sacrificial reflective surface can significantly prolong the useful life of the collector optics and the overall performance of the condenser in which the collector optics are incorporated. The collector optics are normally subject to erosion by debris from laser plasma source of radiation. The presence of an upper sacrificial reflective surface over the underlying reflective surface effectively increases the life of the optics while relaxing the constraints on the radiation source. Spatial and temporally varying reflectivity that results from the use of the sacrificial reflective surface can be accommodated by proper condenser design.

  16. The antireflective potential of dropwise condensation.

    PubMed

    Tow, Emily W

    2014-03-01

    The transmissivity of fogged glass to visible light incident on the dry side is studied with ray tracing to show that condensation can act as an optically thick antireflective coating. A new simulation method is described that uses symmetry relations and analytical expressions for the intersection of rays and surfaces to include all drop-drop and drop-surface interactions between an infinite number of drops. Angle of incidence, droplet contact angle, and surface coverage are varied. The simulation reveals that in the optimal contact angle range, dropwise condensation can decrease the reflectance of glass to below even that of glass coated with a water film.

  17. Novel insights into mitotic chromosome condensation

    PubMed Central

    Piskadlo, Ewa; Oliveira, Raquel A.

    2016-01-01

    The fidelity of mitosis is essential for life, and successful completion of this process relies on drastic changes in chromosome organization at the onset of nuclear division. The mechanisms that govern chromosome compaction at every cell division cycle are still far from full comprehension, yet recent studies provide novel insights into this problem, challenging classical views on mitotic chromosome assembly. Here, we briefly introduce various models for chromosome assembly and known factors involved in the condensation process (e.g. condensin complexes and topoisomerase II). We will then focus on a few selected studies that have recently brought novel insights into the mysterious way chromosomes are condensed during nuclear division. PMID:27508072

  18. Condensation-induced jumping water drops.

    PubMed

    Narhe, R D; Khandkar, M D; Shelke, P B; Limaye, A V; Beysens, D A

    2009-09-01

    Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length approximately 1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface. PMID:19905120

  19. Effects of oxaliplatin on DNA condensation

    NASA Astrophysics Data System (ADS)

    Ju, HaiPeng; Zhang, HongYan; Li, Wei; Wang, PengYe

    2014-11-01

    In this paper the interactions between DNA and anti-cancer drug oxaliplatin were investigated by using magnetic tweezers. The dynamics of DNA condensation due to oxaliplatin was traced under various forces. It is found that torsion constraint in DNA enhances the ability of oxaliplatin for shortening DNA. The transplatin helps oxaliplatin combine to DNA and increase the rate of DNA condensation. All these results are consistent to the previously proposed model and are helpful for further investigation of interaction between DNA and oxaliplatin.

  20. Condensation-induced jumping water drops

    NASA Astrophysics Data System (ADS)

    Narhe, R. D.; Khandkar, M. D.; Shelke, P. B.; Limaye, A. V.; Beysens, D. A.

    2009-09-01

    Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length ˜1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface.

  1. Condensation-induced jumping water drops.

    PubMed

    Narhe, R D; Khandkar, M D; Shelke, P B; Limaye, A V; Beysens, D A

    2009-09-01

    Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length approximately 1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface.

  2. An Overview of Tachyon Condensation and SFT

    NASA Astrophysics Data System (ADS)

    Bonora, L.

    2010-07-01

    This is short review of tachyon condensation and open strig field theory. After a brief introduction to open string theory, the SFT action is introduced and illustrated. Next comes tachyon condensation in the level truncation approach, which introduces the main topic: the description of the analytic solution and the proof of the first two conjectures by Sen. The third conjecture is discussed in the framework of vacuum SFT. Finally the subject of open--closed string duality is tackled by commenting about an attempt at showing a more explicit connection between open and closed strings.

  3. Analytical Treatment of Normal Condensation Shock

    NASA Technical Reports Server (NTRS)

    Heybey

    1947-01-01

    The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.

  4. Rayleigh-Taylor instability in binary condensates

    SciTech Connect

    Gautam, S.; Angom, D.

    2010-05-15

    We propose a well-controlled experimental scheme to initiate and examine the Rayleigh-Taylor instability in two-species Bose-Einstein condensates. We identify the {sup 85}Rb-{sup 87}Rb mixture as an excellent candidate to observe experimentally. The instability is initiated by tuning the {sup 85}Rb-{sup 85}Rb interaction through a magnetic Feshbach resonance. We show that the observable signature of the instability is the damping of the radial oscillations. We also propose a semianalytic scheme to determine the stationary state of binary condensates with the Thomas-Fermi approximation for axisymmetric traps.

  5. Cloud condensation nuclei near marine stratus

    NASA Technical Reports Server (NTRS)

    Hudson, James G.; Frisbie, Paul R.

    1991-01-01

    Extensive airborne measurements of cloud condensation nucleus (CCN) spectra and concentrations of total particles, or condensation nuclei (CN), below, in, and above the stratus cloud decks off the southern California coast point to important aerosol-cloud interactions. Consistently low CCN concentrations below cloud appear to be due to cloud scavenging processes which include Brownian coagulation, nucleation, coalescence, and drizzle. The higher CCN and CN concentrations above cloud are associated with ambient ozone concentrations which suggest a link with continental, probably anthropogenic, sources, even at distances of 500 km from the California coast.

  6. Experimental Investigation of Flow Condensation in Microgravity

    NASA Technical Reports Server (NTRS)

    Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.; Mackey, Jeffery R.

    2013-01-01

    Future manned missions to Mars are expected to greatly increase the space vehicle's size, weight, and heat dissipation requirements. An effective means to reducing both size and weight is to replace single-phase thermal management systems with two-phase counterparts that capitalize upon both latent and sensible heat of the coolant rather than sensible heat alone. This shift is expected to yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients. A major challenge to this shift is a lack of reliable tools for accurate prediction of two-phase pressure drop and heat transfer coefficient in reduced gravity. Developing such tools will require a sophisticated experimental facility to enable investigators to perform both flow boiling and condensation experiments in microgravity in pursuit of reliable databases. This study will discuss the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS), which was initiated in 2012 in collaboration between Purdue University and NASA Glenn Research Center. This facility was recently tested in parabolic flight to acquire condensation data for FC-72 in microgravity, aided by high-speed video analysis of interfacial structure of the condensation film. The condensation is achieved by rejecting heat to a counter flow of water, and experiments were performed at different mass velocities of FC-72 and water and different FC-72 inlet qualities. It is shown that the film flow varies from smooth-laminar to wavy-laminar and ultimately turbulent with increasing FC-72 mass velocity. The heat transfer coefficient is highest near the inlet of the condensation tube, where the film is thinnest, and decreases monotonically along the tube, except for high FC-72 mass velocities, where the heat transfer coefficient is enhanced downstream. This enhancement is attributed to both turbulence and increased interfacial waviness. One-ge correlations are shown to

  7. Neutron star cooling and pion condensation

    NASA Technical Reports Server (NTRS)

    Umeda, Hideyuki; Nomoto, Ken'ichi; Tsuruta, Sachiko; Muto, Takumi; Tatsumi, Toshitaka

    1994-01-01

    The nonstandard cooling of a neutron star with the central pion core is explored. By adopting the latest results from the pion condensation theory, neutrino emissivity is calulated for both pure charged pions and a mixture of charged and neutral pions, and the equations of state are constructed for the pion condensate. The effect of superfluidity on cooling is investigated, adopting methods more realistic than in previous studies. Our theoretical models are compared with the currently updated observational data, and possible implications are explored.

  8. Bose-Einstein condensation. Twenty years after

    DOE PAGES

    Bagnato, V. S.; Frantzeskakis, D. J.; Kevrekidis, P. G.; Malomed, B. A.; Mihalache, D.

    2015-02-23

    The aim of this introductory article is two-fold. First, we aim to offer a general introduction to the theme of Bose-Einstein condensates, and briefly discuss the evolution of a number of relevant research directions during the last two decades. Second, we introduce and present the articles that appear in this Special Volume of Romanian Reports in Physics celebrating the conclusion of the second decade since the experimental creation of Bose-Einstein condensation in ultracold gases of alkali-metal atoms.

  9. Condensation of gauge interacting massless fermions

    SciTech Connect

    Siringo, Fabio

    2004-09-15

    A single massless fermionic field with an Abelian U(1) gauge interaction (electrodynamics of a massless Dirac fermion) is studied by a variational method. Even without the insertion of any extra interaction the vacuum is shown to be unstable towards a particle-antiparticle condensate. The single particle excitations do acquire a mass and behave as massive Fermi particles. An explicit low-energy gap equation has been derived and numerically solved. Some consequences of condensation and mass generation are discussed in the framework of the standard model.

  10. Experiments on condensation over in-line and staggered condenser tubes in the presence of non-condensable gases

    NASA Astrophysics Data System (ADS)

    Ramadan, Abdulghani; Yamali, Cemil

    2013-12-01

    The problem of the forced film condensation heat transfer of pure steam and steam-air mixture flowing downward a tier of horizontal cylinders is investigated experimentally. An experimental setup was manufactured and mounted at Middle East Technical University workshop. A set of experiments were conducted to observe the condensation heat transfer phenomenon and to verify the theoretical results. The results of the experimental investigation are presented to show the effect of different parameters on the film condensation heat transfer phenomenon over bundle of tubes. These parameters include; free stream velocity, free stream non-condensable gas (air) mass fractions, free stream temperature to wall temperature difference, the angle of inclination. heat transfer coefficients are evaluated at different working conditions for both inline and staggered arrangements. Results show that; a remarked reduction in the vapor side heat transfer coefficient is noticed when very small amounts of air mass fractions present in the vapor. In addition, it decreases by increasing the temperature difference. On the other hand, it increases by increasing the free stream velocity (Reynolds number). Average heat transfer coefficient at the middle and the bottom cylinders increases by increasing the angle of inclination, whereas, no significant change is observed for that of the upper cylinder. Although some discrepancies are noticed, the present study results are inline and in a reasonable agreement with the theory and experiment in the literature.

  11. Condensed tannins increase nitrogen recovery by trees following insect defoliation.

    PubMed

    Madritch, Michael D; Lindroth, Richard L

    2015-10-01

    While the importance of plant secondary metabolites to belowground functioning is gaining recognition, the perception remains that secondary metabolites are produced for herbivore defense, whereas their belowground impacts are ecological by-products, or 'afterlife' effects. However, plants invest a significant amount of resources into production of secondary metabolites that have minimal effects on herbivore resistance (e.g. condensed tannins and insect herbivores). We show that genetically mediated variation in condensed tannin concentration is correlated with plant nitrogen recovery following a severe defoliation event. We used single-tree mesocosms labeled with (15) N to track nitrogen through both the frass and litter cycling pathways. High concentrations of leaf tannins in Populus tremuloides were correlated with (15) N recovery from frass within the same growing season and in the following growing season. Likewise, leaf tannin concentrations were also correlated with (15) N recovery from the litter of defoliated trees in the growing season following the defoliation event. Conversely, tannins were not well correlated with nitrogen uptake under conditions of nominal herbivory. Our results suggest that tannins may confer benefits in response to herbivore pressure through conserved belowground nitrogen cycling, rather than via defensive properties. Consequently, tannins may be considered as chemical mediators of tolerance rather than resistance. PMID:25952793

  12. Condensed tannins increase nitrogen recovery by trees following insect defoliation.

    PubMed

    Madritch, Michael D; Lindroth, Richard L

    2015-10-01

    While the importance of plant secondary metabolites to belowground functioning is gaining recognition, the perception remains that secondary metabolites are produced for herbivore defense, whereas their belowground impacts are ecological by-products, or 'afterlife' effects. However, plants invest a significant amount of resources into production of secondary metabolites that have minimal effects on herbivore resistance (e.g. condensed tannins and insect herbivores). We show that genetically mediated variation in condensed tannin concentration is correlated with plant nitrogen recovery following a severe defoliation event. We used single-tree mesocosms labeled with (15) N to track nitrogen through both the frass and litter cycling pathways. High concentrations of leaf tannins in Populus tremuloides were correlated with (15) N recovery from frass within the same growing season and in the following growing season. Likewise, leaf tannin concentrations were also correlated with (15) N recovery from the litter of defoliated trees in the growing season following the defoliation event. Conversely, tannins were not well correlated with nitrogen uptake under conditions of nominal herbivory. Our results suggest that tannins may confer benefits in response to herbivore pressure through conserved belowground nitrogen cycling, rather than via defensive properties. Consequently, tannins may be considered as chemical mediators of tolerance rather than resistance.

  13. Copper-catalyzed chlorination and condensation of acetylene and dichloroacetylene.

    PubMed

    Taylor, P H; Wehrmeier, A; Sidhu, S S; Lenoir, D; Schramm, K W; Kettrup, A

    2000-06-01

    The chlorination and condensation of acetylene at low temperatures is demonstrated using copper chlorides as chlorinated agents coated to model borosilicate surfaces. Experiments with and without both a chlorine source and borosilicate surfaces indicate the absence of gas-phase and gas-surface reactions. Chlorination and condensation occur only in the presence of the copper catalyst. C2 through C8 organic products were observed in the effluent; PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed that is consistent with the observed product distributions. Similar experiments with dichloroacetylene indicate greater reactivity in the absence of the copper catalyst. Reaction is observed in the gas-phase and in the presence of borosilicate surfaces at low temperatures. The formation of hexachlorobenzene is only observed in the presence of a copper catalyst. PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed for the formation of hexachlorobenzene from dichloroacetylene. PMID:10789968

  14. Condensation heat transfer on two-tier superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Cheng, Jiangtao; Vandadi, Aref; Chen, Chung-Lung

    2012-09-01

    We investigated water vapor condensation on a two-tier superhydrophobic surface in an environmental scanning electron microscope (ESEM) and in a customer-designed vapor chamber. We have observed continuous dropwise condensation (DWC) on the textured surface in ESEM. However, a film layer of condensate was formed on the multiscale texture in the vapor chamber. Due to the filmwise condensation, the condensation heat transfer coefficient of the superhydrophobic surface is lower than that of a flat hydrophobic surface especially under high heat flux situations. Our studies indicate that adaptive and prompt condensate droplet purging is the dominant factor for sustaining long-term DWC.

  15. Condensation Enhancement by Surface Porosity: Three-Stage Mechanism.

    PubMed

    Yarom, Michal; Marmur, Abraham

    2015-08-18

    Surface defects, such as pores, cracks, and scratches, are naturally occurring and commonly found on solid surfaces. However, the mechanism by which such imperfections promote condensation has not been fully explored. In the current paper we thermodynamically analyze the ability of surface porosity to enhance condensation on a hydrophilic solid. We show that the presence of a surface-embedded pore brings about three distinct stages of condensation. The first is capillary condensation inside the pore until it is full. This provides an ideal hydrophilic surface for continuing the condensation. As a result, spontaneous condensation and wetting can be achieved at lower vapor pressure than on a smooth surface.

  16. Enhancing Condensers for Geothermal Systems: the Effect of High Contact Angles on Dropwise Condensation Heat Transfer

    SciTech Connect

    Kennedy, John M.; Kim, Sunwoo; Kim, Kwang J.

    2009-10-06

    Phase change heat transfer is notorious for increasing the irreversibility of, and therefore decreasing the efficiency of, geothermal power plants. Its significant contribution to the overall irreversibility of the plant makes it the most important source of inefficiency in the process. Recent studies here have shown the promotion of drop wise condensation in the lab by means of increasing the surface energy density of a tube with nanotechnology. The use of nanotechnology has allowed the creation of surface treatments which discourage water from wetting a tube surface during a static test. These surface treatments are unique in that they create high- contact angles on the condensing tube surfaces to promote drop wise condensation.

  17. 7 CFR 58.938 - Physical requirements and microbiological limits for sweetened condensed milk.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Administration for sweetened condensed milk (21 CFR 131.120). In addition, the quantity of refined sugar used... Sediment Standard for Milk and Milk Products (7 CFR 58.2726). ... retain a definite form. (e) Microbiological limits. (1) Coliforms, less than 10 per gram; (2)...

  18. 7 CFR 58.938 - Physical requirements and microbiological limits for sweetened condensed milk.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Sediment Standard for Milk and Milk Products (7 CFR 58.2726). ... Administration for sweetened condensed milk (21 CFR 131.120). In addition, the quantity of refined sugar used shall be sufficient to give a sugar-in-water ratio of not less than 61.5 percent. (h) Sediment....

  19. 7 CFR 58.938 - Physical requirements and microbiological limits for sweetened condensed milk.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Sediment Standard for Milk and Milk Products (7 CFR 58.2726). ... Administration for sweetened condensed milk (21 CFR 131.120). In addition, the quantity of refined sugar used shall be sufficient to give a sugar-in-water ratio of not less than 61.5 percent. (h) Sediment....

  20. 7 CFR 58.938 - Physical requirements and microbiological limits for sweetened condensed milk.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Sediment Standard for Milk and Milk Products (7 CFR 58.2726). ... Administration for sweetened condensed milk (21 CFR 131.120). In addition, the quantity of refined sugar used shall be sufficient to give a sugar-in-water ratio of not less than 61.5 percent. (h) Sediment....

  1. 7 CFR 58.938 - Physical requirements and microbiological limits for sweetened condensed milk.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Administration for sweetened condensed milk (21 CFR 131.120). In addition, the quantity of refined sugar used... Sediment Standard for Milk and Milk Products (7 CFR 58.2726). ... retain a definite form. (e) Microbiological limits. (1) Coliforms, less than 10 per gram; (2)...

  2. The improvement of the effectiveness of using natural gas in hot-water boilers by means of condensing economizers

    NASA Astrophysics Data System (ADS)

    Vnukov, A. K.; Rozanova, F. A.

    2013-07-01

    The paper describes the results of the study of the mathematical model of a condensing economizer (CE) interacting with the technological parameter of the particular district heating station. This model has been developed by the authors. It is shown that the CE, due to condensation of water vapor and augmentation of convective heat exchange between products of natural gas combustion, makes it possible to save up to 8% of fuel.

  3. Dropwise condensation on a cold gradient substrate

    NASA Astrophysics Data System (ADS)

    Macner, Ashley; Daniel, Susan; Steen, Paul

    2012-11-01

    Distributions of drops that arise from dropwise condensation evolve by nucleation, growth, and coalescence of drops. An understanding of how surface-energy gradients applied to the substrate affect drop growth and coalescence is needed for design of effective surfaces for large-scale dropwise condensation. Transient dropwise condensation from a vapor phase onto a cold and chemically treated surface is reported. The surfaces were treated to deliver either a uniform contact-angle or a gradient of contact-angles by silanization. The time evolution of drop-size and number-density distributions is reported. For a typical condensation experiment, the drop distributions advance through two stages: an increase in drop density as a result of nucleation and a decrease in drop density as a result of larger scale coalescence events. Because the experiment is transient in nature, the shape of the distribution can be used to predict the number of drop generations and their stage of development. Preliminary results for gradient surfaces will be discussed and compared against observations of behavior on uniformly coated surfaces. NASA Space Technology Research Fellowship (NSTRF).

  4. Condensate-removal device for heat exchangers

    NASA Technical Reports Server (NTRS)

    Trusch, R. B.; Oconnor, E. W.

    1973-01-01

    Device comprises array of perforated tubes manifolded together and connected to a vacuum suction device. Vacuum applied to these tubes pulls mixture of condensate and effluent gas through perforations and along length of tubes to discharge device. Discharge device may be a separator which separates water vapor from effluent air and allows recirculation of both of them.

  5. Condensing Organic Aerosols in a Microphysical Model

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Tsigaridis, K.; Bauer, S.

    2015-12-01

    The condensation of organic aerosols is represented in a newly developed box-model scheme, where its effect on the growth and composition of particles are examined. We implemented the volatility-basis set (VBS) framework into the aerosol mixing state resolving microphysical scheme Multiconfiguration Aerosol TRacker of mIXing state (MATRIX). This new scheme is unique and advances the representation of organic aerosols in models in that, contrary to the traditional treatment of organic aerosols as non-volatile in most climate models and in the original version of MATRIX, this new scheme treats them as semi-volatile. Such treatment is important because low-volatility organics contribute significantly to the growth of particles. The new scheme includes several classes of semi-volatile organic compounds from the VBS framework that can partition among aerosol populations in MATRIX, thus representing the growth of particles via condensation of low volatility organic vapors. Results from test cases representing Mexico City and a Finish forrest condistions show good representation of the time evolutions of concentration for VBS species in the gas phase and in the condensed particulate phase. Emitted semi-volatile primary organic aerosols evaporate almost completely in the high volatile range, and they condense more efficiently in the low volatility range.

  6. Orientation Dependence of Jumping Droplet Condensation

    NASA Astrophysics Data System (ADS)

    Berrier, Austin; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    On nanostructured superhydrophobic surfaces, microscopic condensate exhibits out-of-plane jumping that minimizes the average droplet size for maximal phase-change heat transfer. This jumping-droplet phenomenon occurs independently of gravity and is due to surface energy being partially converted to kinetic energy upon coalescence events. Although the initial departure of the jumping droplets is independent of gravity, the subsequent trajectories exhibit a dependence upon the orientation of the substrate. The drop size distribution of jumping-droplet condensation growing on a superhydrophobic substrate was characterized for both horizontal and vertical surface orientations. With the horizontal orientation, jumping condensate returns to the substrate by gravity. While this can result in chain reactions with other droplets to trigger further jumping events, eventually the rebounding droplets become too large to jump and are stuck on the surface. In contrast, droplets jumping off a vertically oriented surface do not return to the substrate. For this reason, the maximum droplet diameters during condensation growth were found to be significantly larger on the horizontally oriented superhydrophobic surface than on the vertical orientation.

  7. THE COLOR GLASS CONDENSATE, RHIC AND HERA.

    SciTech Connect

    MCLERRAN,L.

    2002-04-30

    In this talk, I discuss a universal form of matter, the Color Glass Condensate. It is this matter which composes the low x part of all hadronic wavefunctions. The experimental programs at RHIC and HERA, and future programs at LHC and eRHIC may allow us to probe and study the properties of this matter.

  8. Condensation enhancement by means of electrohydrodynamic techniques

    NASA Astrophysics Data System (ADS)

    Butrymowicz, Dariusz; Karwacki, Jarosław; Trela, Marian

    2014-12-01

    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. Condensate fraction in superfluid 4He

    NASA Astrophysics Data System (ADS)

    Olinto, A. C.

    1987-04-01

    Recently, a relationship between the chemical potential and the condensate fracton n0(T) has been derived for all temperatures in the superfluid region. An analysis of liquid 4He chemical-potential data yields n0(T=0)=0.062, and n0(T) is in excellent agreement with the empirical results of Svensson, Sears, and Griffin.

  10. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Not Available

    1990-01-01

    This project addresses the problem of acid mist formed by condensation of sulfuric acid vapor in flue gas from coal-fired utility boilers. Acid mists can sometimes constitute a significant portion of the total particulate emissions from power plants burning high-sulfur coals. Complete condensation of 10 ppM of acid vapor produces a condensed acid mass loading of about 0.02 gr/dscf or 0.03 lb/MBtu, equivalent to the total allowable mass emissions under the revised (1979) New Source Performance Standards (2). The purpose of this project is to develop and demonstrated a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. The project is organized in two phases. Phase I involved the WESP fabrication, laboratory and pilot combustor testing, and computer modeling. Phase II involves the solicitation of a utility demonstration site, preliminary site measurements, and planning for the demonstration test program. Only Phase II work will be addressed in this discussion which includes: site selection, site measurements, computer modeling and demonstration plan, and phase II reporting. 9 refs., 11 figs., 7 tabs.

  11. A Moment-Based Condensed History Algorithm

    SciTech Connect

    Tolar, D.R.; Larsen, E.W.

    2000-06-15

    ''Condensed History'' algorithms are Monte Carlo models for electron transport problems, They describe the aggregate effect of multiple collisions that occur when an electron travels a path length s{sub 0}. This path length is the distance each Monte Carlo electron travels between Condensed History steps. Conventional Condensed History schemes employ a splitting routine over the range 0 {le} s {le} s{sub 0}. For example, the Random Hinge method splits each path length step into two substeps; one with length {xi}s{sub 0} and one with length (1-{xi})s{sub 0}, where {xi} is a random number from 0 < {xi} < 1. Here we develop a new Condensed History algorithm to improve the accuracy of electron transport simulations by preserving the mean position and the variance in the mean of electrons that have traveled a path length s and are traveling with the direction cosine {mu}. These means and variances are obtained from the zeroth-, first-, and second-order spatial moments of the Boltzmann transport equation. Hence, our method is a Monte Carlo application of the ''Method of Moments''.

  12. Activity, purification, and analysis of condensed tannins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  13. A transport-based condensed history algorithm

    SciTech Connect

    Tolar Jr, D R

    1999-01-06

    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{sub 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{sub 0}. For example, the PEnELOPE method splits each step into two substeps; one with length {xi}s{sub 0} and one with length (1 {minus}{xi})s{sub 0}, where {xi} is a random number from 0 < {xi} < 1. because s{sub 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.

  14. Convection in Condensible-rich Atmospheres

    NASA Astrophysics Data System (ADS)

    Ding, F.; Pierrehumbert, R. T.

    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 CO2 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.

  15. Imaging of DNA/Nanosphere Condensates

    NASA Astrophysics Data System (ADS)

    Krishnan, R.

    2005-03-01

    DNA forms condensates in a variety of environments. In chromatin, DNA is condensed around 10-nm-diameter, positively-charged histone complexes. To model chromatin formation in cells, lambda-phage (16 microns long) and herring sperm (0.03 to1 micron) DNAs were mixed with polystyrene nanospheres of diameter 40nm and 930nm containing 1.8x10^4 and 2.6x10^8 positive surface charges, respectively, to form condensates. Sphere concentrations were 1-2 times the isoelectric concentration. Condensation vs time was imaged at various concentrations, pH's, viscosities, and ionic strengths. Bright-field and fluorescence (YOYO-1 dye bound to DNA) images were recorded. In general HS DNA aggregate size increased with time. Except in 0.5-0.8 M KCl, herring sperm DNA formed one huge aggregate (100's of microns) and depleted other areas, both in 10% and 20% glycerol. Phage DNA samples rapidly formed longer, fiber-like aggregates. Within 2 hours it formed ordered structures and in most samples, empty, apparently depleted regions were found in the viewing area. Shapes of the phage-DNA aggregates in 20% glycerol, in contrast, formed small clumps like HS DNA.

  16. Condenser designs for binary power cycles

    SciTech Connect

    Michel, J.W.; Murphy, R.W.

    1980-01-01

    For the past four years, work has been in progress at ORNL to develop improved condensers for geothermal binary power cycles. The work has centered on optimizing the design variables associated with fluted surfaces on vertical tubes and comparing the tube performance with available enhanced tubes either for vertical or horizontal operation. Data with seven fluids including a hydrocarbon, fluorocarbons, and ammonia condensing on up to 30 different tubes have been obtained. Data for tubes of different effective lengths (0.15 to 1.20 m) and inclination have also been obtained. The primary conclusion from this work is that fluted tubes can provide an enhancement in condensation coefficient of a factor of 6 over smooth vertical tubes and a factor of 2 over enhanced commercial tubes either operating vertically or horizontally. These data, together with field test data, have formed the basis for designing two prototype condensers, one for the 60 kWe Raft River, Idaho, pilot plant and one for the 500 kWe East Mesa, California, direct-contact demonstration plant.

  17. Free convective condensation in a vertical enclosure

    SciTech Connect

    Fox, R.J.; Peterson, P.F.; Corradini, M.L.; Pernsteiner, A.P.

    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.

  18. Condensation in a two-phase pool

    SciTech Connect

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

    1991-12-31

    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.

  19. Condensation in a two-phase pool

    SciTech Connect

    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.

  20. 242-A evaporator vacuum condenser system

    SciTech Connect

    Smith, V.A.

    1994-09-28

    This document is written for the 242-A evaporator vacuum condenser system (VCS), describing its purpose and operation within the evaporator. The document establishes the operating parameters specifying pressure, temperature, flow rates, interlock safety features and interfacing sub-systems to support its operation.