Sample records for two-layer tbp oxidation

  1. Study on Properties of TBP-HNO3 Complex Used for Direct Dissolution of Lanthanide and Actinide Oxides in Supercritical Fluid CO2

    Institute of Scientific and Technical Information of China (English)

    DUAN Wu-Hua; ZHU Li-Yang; JING Shan; ZHU Yong-Jun; CHEN Jing


    The tri-n-butyl phosphate-nitric acid (TBP-HNO3) complex prepared by contacting the pure TBP with the concentrated HNO3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide (SCF-CO2). Properties of the TBP-HNO3 complex have been studied. Experimental results showed that when the initial HNO3/TBP volume ratio was varied from 1 : 7 to 5 : 1, the concentration of HNO3 in the TBP-HNO3 complex changed from 1.95 to 5.89 mol/L, the [HNO3]/[TBP] ratio of the TBP-HNO3 complex changed from 0.61 to 2.22, and the content of H2O in the TBP-HNO3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO3 complex changed with the concentration of HNO3 in the complex, and were higher than those of the pure TBP. The protons of HNO3 and H2O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO3 were formed that can be detected by NMR.

  2. High-Performanced Cathode with a Two-Layered R-P Structure for Intermediate Temperature Solid Oxide Fuel Cells. (United States)

    Huan, Daoming; Wang, Zhiquan; Wang, Zhenbin; Peng, Ranran; Xia, Changrong; Lu, Yalin


    Driven by the mounting concerns on global warming and energy crisis, intermediate temperature solid-oxide fuel cells (IT-SOFCs) have attracted special attention for their high fuel efficiency, low toxic gas emission, and great fuel flexibility. A key obstacle to the practical operation of IT-SOFCs is their sluggish oxygen reduction reaction (ORR) kinetics. In this work, we applied a new two-layered Ruddlesden-Popper (R-P) oxide, Sr3Fe2O7-δ (SFO), as the material for oxygen ion conducting IT-SOFCs. Density functional theory calculation suggested that SFO has extremely low oxygen ion formation energy and considerable energy barrier for O(2-) diffusion. Unfortunately, the stable SrO surface of SFO was demonstrated to be inert to O2 adsorption and dissociation reaction, and thus restricts its catalytic activity toward ORR. Based on this observation, Co partially substituted SFO (SFCO) was then synthesized and applied to improve its surface vacancy concentration to accelerate the oxygen adsorptive reduction reaction rate. Electrochemical performance results suggested that the cell using the SFCO single phase cathode has a peak power density of 685 mW cm(-2) at 650 °C, about 15% higher than those when using LSCF cathode. Operating at 200 mA cm(-2), the new cell using SFCO is quite stable within the 100-h' test.

  3. Analysis list: Tbp [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Tbp Blood,Embryonic fibroblast,Liver,Placenta,Pluripotent stem cell + mm9,,,http://d

  4. Analysis list: Tbp [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Tbp Embryo + dm3 ...

  5. Analysis list: tbp-1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available tbp-1 Embryo + ce10 ...

  6. TBP-associated factors in Arabidopsis. (United States)

    Lago, Clara; Clerici, Elena; Mizzi, Luca; Colombo, Lucia; Kater, Martin M


    Initiation of transcription mediated by RNA polymerase II requires a number of transcription factors among which TFIID is the major core promoter recognition factor. TFIID is composed of highly conserved factors which include the TATA-binding protein (TBP) and about 14 TBP-associated factors (TAFs). Since TAFs play important roles in transcription they have been extensively studied in organisms like yeast, Drosophila and human. Surprisingly, TAFs have been poorly characterized in plants. With the completion of the Arabidopsis genome sequence, it is possible to search for TAFs, since many of them have conserved amino acid sequences. Mining the genome of Arabidopsis for TAFs resulted in the identification of 18 putative Arabidopsis TAFs (AtTAFs). We have analyzed their protein structure and their genomic localisation. Expression profiling by RT-PCR showed that these TAFs are expressed in all parts of the plant which is in agreement with their general role in transcription. These analyses in combination with their evolutionary conservation with TAFs of other organisms are discussed.


    Institute of Scientific and Technical Information of China (English)

    GaoHaoqi; CaoZhikai; 等


    Adsorption of gold on TBP extracting resin from HCl solution was researched.All the effects of factors,such as solution acidity,TBP content,temperature,etc.,on adsorption equilibrium were discussed and the equilibrium equation was formulated.The breakthough time of adsorption process with fixed bed was studied through experiment.

  8. Recovery of Pu,Np in 1BP of Dilute TBP Extraction Process

    Institute of Scientific and Technical Information of China (English)


    <正>In the TBP extraction process, Np and Pu need to be recovered from effluents of the TBP extraction process. In this work, the recovery of Np and Pu from TBP extraction effluents is studied was investigated

  9. Two-Layer Quantum Key Distribution

    CERN Document Server

    Ramos, Rubens Viana


    Recently a new quantum key distribution protocol using coherent and thermal states was proposed. In this work this kind of two-layer QKD protocol is formalized and its security against the most common attacks, including external control and Trojan horse attacks, is discussed.


    Institute of Scientific and Technical Information of China (English)

    Dong-dong Peng; Ran-xing Nancy Li; Chi-hang Lam; Ophelia K.C.Tsui


    Experiments in the past two decades have shown that the glass transition temperature of polymer films can become noticeably different from that of the bulk when the film thickness is decreased below ca.100 nm.It is broadly believed that these observations are caused by a nanometer interfacial layer with dynamics faster or slower than that of the bulk.In this paper,we examine how this idea may be realized by using a two-layer model assuming a hydrodynamic coupling between the interfacial layer and the remaining,bulk-like layer in the film.Illustrative examples will be given showing how the two-layer model is applied to the viscosity measurements of polystyrene and polymethylmethacrylate films supported by silicon oxide,where divergent thickness dependences are observed.

  11. Development of a new surfactant liquid formulation for TBP removal in reprocessing plants for decommissioning purposes

    Energy Technology Data Exchange (ETDEWEB)

    Fournel, B.; Bisel, I.; Pochon, P.; Delagrange, J.; Fulconis, J.M. [French Atomic Energy Commission, CEA/Siege, 31-33, rue de la Federation, 75752 Paris cedex 15 (France); Causse, J. [Universite de Montpellier, Place Eugene Bataillon 34095 Montpellier Cedex II (France)


    eliminated by working in acidic conditions. Moreover, secondary liquid wastes can be easily addressed to the vitrification unit as they contain no sodium ions. A pretreatment including oxidation with peroxide hydrogen and evaporation has been further validated. The scale one experiment is being now set up at the Pilot Reprocessing Facility in Marcoule. In the future, it is aimed to benefit from this experiment in the frame of larger scale decommissioning projects. In parallel to these industrial objectives, basic studies have been launched together with Montpellier University to get a better understanding of basic phenomena involved in the TBP solubilization.

  12. The brominated flame retardants TBP-AE and TBP-DBPE antagonize the chicken androgen receptor and act as potential endocrine disrupters in chicken LMH cells. (United States)

    Asnake, Solomon; Pradhan, Ajay; Kharlyngdoh, Joubert Banjop; Modig, Carina; Olsson, Per-Erik


    Increased exposure of birds to endocrine disrupting compounds has resulted in developmental and reproductive dysfunctions. We have recently identified the flame retardants, allyl-2,4,6-tribromophenyl ether (TBP-AE), 2-3-dibromopropyl-2,4,6-tribromophenyl ether (TBP-DBPE) and the TBP-DBPE metabolite 2-bromoallyl-2,4,6-tribromophenyl ether (TBP-BAE) as antagonists to both the human androgen receptor (AR) and the zebrafish AR. In the present study, we aimed at determining whether these compounds also interact with the chicken AR. In silico modeling studies showed that TBP-AE, TBP-BAE and TBP-DBPE were able to dock into to the chicken AR ligand-binding pocket. In vitro transfection assays revealed that all three brominated compounds acted as chicken AR antagonists, inhibiting testosterone induced AR activation. In addition, qRT-PCR studies confirmed that they act as AR antagonists and demonstrated that they also alter gene expression patterns of apoptotic, anti-apoptotic, drug metabolizing and amino acid transporter genes. These studies, using chicken LMH cells, suggest that TBP-AE, TBP-BAE and TBP-DBPE are potential endocrine disrupters in chicken.

  13. File list: Oth.PSC.50.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.50.Tbp.AllCell mm9 TFs and others Tbp Pluripotent stem cell SRX022047,SRX09...1896,SRX022048,SRX159084 ...

  14. File list: Oth.ALL.05.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.Tbp.AllCell dm3 TFs and others Tbp All cell types SRX197575,SRX197571,SR...X197570,SRX372806,SRX372807,SRX197583,SRX197584 ...

  15. File list: Oth.ALL.20.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.20.Tbp.AllCell dm3 TFs and others Tbp All cell types SRX197575,SRX197571,SR...X372806,SRX197570,SRX372807,SRX197583,SRX197584 ...

  16. File list: Oth.PSC.10.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.10.Tbp.AllCell mm9 TFs and others Tbp Pluripotent stem cell SRX091896,SRX02...2047,SRX022048,SRX159084 ...

  17. File list: Oth.PSC.20.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.20.Tbp.AllCell mm9 TFs and others Tbp Pluripotent stem cell SRX022047,SRX09...1896,SRX022048,SRX159084 ...

  18. File list: Oth.Emb.50.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Emb.50.Tbp.AllCell dm3 TFs and others Tbp Embryo SRX197575,SRX372806,SRX197571,...SRX197570,SRX372807,SRX197583,SRX197584 ...

  19. File list: Oth.Emb.05.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Emb.05.Tbp.AllCell dm3 TFs and others Tbp Embryo SRX197575,SRX197571,SRX197570,...SRX372806,SRX372807,SRX197583,SRX197584 ...

  20. Cloning and Expression of Actinobacillus pleuropneumoniae Gene Coding for TbpA and Development of an Indirect TbpA-ELISA

    Institute of Scientific and Technical Information of China (English)

    LIANG Wang-wang; HE Qi-gai; CHEN Huan-chun; XU Di-ping; WU Rui; ZHANG Rong-rong


    This study presents the cloning and expression of gene encoding transferrin-binding protein A from Actinobacillus pleuropneumoniae in Escherichia coli expression system and the development of an indirect TbpA-ELISA. The gene coding TbpA was amplified from the A. pleuropneumoniae serotype 2 genome using polymerase chain reaction and cloned to pET-28b expression vector under the control of strong, inducible T7 promoter. The recombinant plasmid was expressed in E. coli BL21 (DE3). The expressed fusion protein was analyzed using SDS-PAGE and Western blotting. The diagnostic potential of recombinant TbpA (rTbpA) was evaluated through an antibody-detection indirect ELISA based on the purified rTbpA. The TbpA antibodies were detectable in mice on day 7 after vaccination with purified rTbpA protein or infection with A. pleuropneumoniae serotype 10 with the TbpA-based ELISA. In addition, the TbpA-ELISA was able to detect 12 serotyping rabbit antisera postinoculation (PI) with A. pleuropneumoniae 12 serotypes experimentally. The comparable result was obtained by detecting the 117 clinical serum samples using, respectively, the TbpA-ELISA and indirect hemagglutination test (IHA) based on multiplex antigen. The result indicates that the TbpA-ELISA was the more sensitive method compared with the Mix-IHA method because of its consistent presence in A. pleuropneumoniae serotypes. In conclusion, the conserved TbpA of A. pleuropneumoniae can be used for the development of a cross-serotype diagnostic method for the detection of antibodies against A. pleuropneumoniae.

  1. Radiolysis of TBP in the presence of plutonium and uranium

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, I.A.; Kermanova, N.V.; Vladimirova, M.V.

    The yields of the decomposition products of TBP as the result of ..cap alpha..- and ..gamma..-radiolysis in the two-phase system 30% TBP in n-paraffin-3.0 moles/liter HNO/sub 3/ in the presence of Pu (sup/IV/) (10/sup -3/-10/sup -1/ mole/liter) and U(sup/VI/) (0.01-0.3 mole/liter) are determined by the methods of potentiometry, spectrophotometry, and chromatography. The yields of the formation of complexes of Pu (sup/IV/) with dibutylphosphoric acid (DBPA) and monobutylphosphoric acid (MBPA) are determined in the two-phase system studied. It is shown that with an increase of (Me) from 0.01 to 0.3 mole/liter, G, DBPA is increased from 1.9 to 3.0, and G, MBPA from 0.3 to 0.45 molecules /100 eV. The radiation gas, the composition, and the yields of gaseous radiolysis products of the organic phase are studied. The kinetics of the formation of DBPA in the presence of plutonium are considered. The velocity constants of the formation and decomposition of DBPA are determined. Based on the experimental data, the maximum decomposition yield of TBP is calculated, equal to approx.6.0 molecules/100 eV.

  2. File list: Oth.ALL.50.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.Tbp.AllCell mm9 TFs and others Tbp All cell types SRX202800,SRX202801,SR...X140376,SRX022047,SRX140363,SRX091896,SRX026512,SRX547082,SRX547083,SRX160415,SRX022048,SRX159084 ...

  3. File list: Oth.ALL.05.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.Tbp.AllCell mm9 TFs and others Tbp All cell types SRX202801,SRX202800,SR...X140376,SRX022047,SRX140363,SRX091896,SRX022048,SRX547082,SRX026512,SRX160415,SRX159084,SRX547083 ...

  4. File list: Oth.ALL.20.Tbp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.20.Tbp.AllCell mm9 TFs and others Tbp All cell types SRX202800,SRX022047,SR...X202801,SRX091896,SRX140363,SRX140376,SRX547082,SRX022048,SRX026512,SRX160415,SRX547083,SRX159084 ...

  5. Extraction of Aminobenzoic Acid with TOA and TBP

    Institute of Scientific and Technical Information of China (English)

    张瑾; 戴猷元


    A series of extraction equilibrium experiments for aminobenzoic acid were carried out. Tri-n-octylamine (TOA) and tributyl phosphate (TBP) were selected as complexing agents. 1-Octanol and kerosene were selected as diluents. The effects of extractant concentration and pH on the distribution ratio were discussed in detail. It was found that there are ion-pair association and hydrogen-bond complexing in the extraction. Expressions of the equilibrium distribution for different solvent systems are proposed. The precision of the models is satisfactoy.

  6. Extraction Behaviour of Hexavalent Plutonium in the System of Dilute TBP/Kerosene

    Institute of Scientific and Technical Information of China (English)


    On the basis of the preparation and stabilization of Pu(Ⅵ), the distribution of it between dilute TBP/kerosene and aqueous phase is studied. The influences of the concentration of TBP, HNO3, A1(NO3)3, TBP and UO2(NO3)2 on the extraction of Pu(Ⅵ) by 5%TBP/kerosene are investigated at 28 ℃. The extraction reaction equation, the corresponding apparent equilibrium constant and the free energy change of it at temperature of 28 ℃ are obtained as follows:

  7. Interfacial Stability in a Two-Layer Benard Problem. (United States)


    STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy Technical Summary Report #2814 April 1985 I cti- Work Unit Number 2 - Physical Mathematics...34•"• -••’-’• ^ ••’••• VI , •• W -•- • •- ’•"• INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy I. INTRODUCTION Two layers of fluids are...Subtltl») INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM 7. AUTMORf.; Yuriko Renardy »• PERFORMING ORGANIZATION NAME AND ADDRESS

  8. Molecular Mechanism of Mot1, a TATA-binding Protein (TBP)-DNA Dissociating Enzyme. (United States)

    Viswanathan, Ramya; True, Jason D; Auble, David T


    The essential Saccharomyces cerevisiae ATPase Mot1 globally regulates transcription by impacting the genomic distribution and activity of the TATA-binding protein (TBP). In vitro, Mot1 forms a ternary complex with TBP and DNA and can use ATP hydrolysis to dissociate the TBP-DNA complex. Prior work suggested an interaction between the ATPase domain and a functionally important segment of DNA flanking the TATA sequence. However, how ATP hydrolysis facilitates removal of TBP from DNA is not well understood, and several models have been proposed. To gain insight into the Mot1 mechanism, we dissected the role of the flanking DNA segment by biochemical analysis of complexes formed using DNAs with short single-stranded gaps. In parallel, we used a DNA tethered cleavage approach to map regions of Mot1 in proximity to the DNA under different conditions. Our results define non-equivalent roles for bases within a broad segment of flanking DNA required for Mot1 action. Moreover, we present biochemical evidence for two distinct conformations of the Mot1 ATPase, the detection of which can be modulated by ATP analogs as well as DNA sequence flanking the TATA sequence. We also show using purified complexes that Mot1 dissociation of a stable, high affinity TBP-DNA interaction is surprisingly inefficient, suggesting how other transcription factors that bind to TBP may compete with Mot1. Taken together, these results suggest that TBP-DNA affinity as well as other aspects of promoter sequence influence Mot1 function in vivo.

  9. Theoretical Permeability of Two-layered Nonwoven Geotextiles

    Institute of Scientific and Technical Information of China (English)

    LIU Li-fang; CHU Cai-yuan


    The two-layered nonwoven geotextile, which consists of a layer constructed with fine fibers for providing optimal filtration characteristics and another layer constructed with coarse fibers for providing the required mechanical properties, is desirable for drainage and filtration system.Based on Darcy's law and drag force theory, a mathematical model on vertical permeability coefficient of two-layered nonwoven geotextile is estabilished. Comparison with experimental results shows that the present model possesses 83.6% accuracy for needle-punched two-layered nonwoven geotextiles. And experimental results also show that with the increasing of needle density the vertical permeability coefficient of two-layered nonwoven geotextiless firstly decreases and then increases, reaching the smallest value at 470 p/cm2.

  10. Separation of zirconium and hafnium by solvent extraction using mixture of TBP and Cyanex 923

    Energy Technology Data Exchange (ETDEWEB)

    Taghizadeh, M., E-mail: [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, End of North Karegar Ave., P.O. Box 14395-836, Tehran (Iran, Islamic Republic of); Ghanadi, M.; Zolfonoun, E. [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, End of North Karegar Ave., P.O. Box 14395-836, Tehran (Iran, Islamic Republic of)


    In this study, a new Zr/Hf separation procedure by solvent extraction is proposed. The method is based on using the mixture of TBP and Cyanex 923 as extractant in the organic phase. Several parameters including; TBP/Cyanex 923 volume ratio, extractant concentration in the organic phase, nitric acid and NaNO{sub 3} concentration in aqueous phase have been investigated. The results demonstrate better condition respect to traditional TBP/HNO{sub 3} process. Lower required acid concentration and more zirconium extraction are some advantages of the new separation process.

  11. Separation of zirconium and hafnium by solvent extraction using mixture of TBP and Cyanex 923 (United States)

    Taghizadeh, M.; Ghanadi, M.; Zolfonoun, E.


    In this study, a new Zr/Hf separation procedure by solvent extraction is proposed. The method is based on using the mixture of TBP and Cyanex 923 as extractant in the organic phase. Several parameters including; TBP/Cyanex 923 volume ratio, extractant concentration in the organic phase, nitric acid and NaNO 3 concentration in aqueous phase have been investigated. The results demonstrate better condition respect to traditional TBP/HNO 3 process. Lower required acid concentration and more zirconium extraction are some advantages of the new separation process.

  12. Study of the extraction mechanisms by TBP saturated by uranyl nitrate; Etude des mecanismes d'extraction du TBP sature par le nitrate d'uranyle

    Energy Technology Data Exchange (ETDEWEB)

    Meze, F


    This work deals with a particular phenomenon likely to occur in the nuclear waste reprocessing process PUREX. It was shown earlier by Russian works that the extractant molecule, tributyl phosphate (TBP), saturated by uranyl nitrate keeps its extraction capacities for nitric acid and tetravalent actinides. This study is composed of three parts. Firstly, some liquid-liquid extraction experiments were conducted to verify the ability of TBP saturated by uranyl nitrate to conserve its extraction capacities for nitric acid. Then, during these experiments, the UV and infrared spectra of both phases were recorded to obtain the organic phase speciation. At last, the informations gathered during the experimental part were used to build a general species distribution model of the H{sub 2}O/HNO{sub 3}/UO{sub 2}(NO{sub 3}){sub 2}/TBP system. (author)

  13. Transcriptional activation requires protection of the TATA-binding protein Tbp1 by the ubiquitin-specific protease Ubp3. (United States)

    Chew, Boon Shang; Siew, Wee Leng; Xiao, Benjamin; Lehming, Norbert


    Tbp1, the TATA-binding protein, is essential for transcriptional activation, and Gal4 and Gcn4 are unable to fully activate transcription in a Saccharomyces cerevisiae TBP1E86D mutant strain. In the present study we have shown that the Tbp1E186D mutant protein is proteolytically instable, and we have isolated intragenic and extragenic suppressors of the transcription defects of the TBP1E186D mutant strain. The TBP1R6S mutation stabilizes the Tbp1E186D mutant protein and suppresses the defects of the TBP1E186D mutant strain. Furthermore, we found that the overexpression of the de-ubiquitinating enzyme Ubp3 (ubiquitin-specific protease 3) also stabilizes the Tbp1E186D mutant protein and suppresses of the defects of the TBP1E186D mutant strain. Importantly, the deletion of UBP3 and its cofactor BRE5 lead to increased degradation of wild-type Tbp1 protein and to defects in transcriptional activation by Gal4 and Gcn4. Purified GST (glutathione transferase)-Ubp3 reversed Tbp1 ubiquitination, and the deletion of UBP3 lead to the accumulation of poly-ubiquitinated species of Tbp1 in a proteaseome-deficient genetic background, demonstrating that Ubp3 reverses ubiquitination of Tbp1 in vitro and in vivo. Chromatin immunoprecipitation showed that Ubp3 was recruited to the GAL1 and HIS3 promoters upon the induction of the respective gene, indicating that protection of promoter-bound Tbp1 by Ubp3 is required for transcriptional activation.

  14. Compound of Feed for Pyrolyzing and Combusting Spent TBP/Kerosene

    Institute of Scientific and Technical Information of China (English)


    Pyrolysis and combustion technology is an available method to treat spent organic solvent, such asintermediate-level radioactive TBP /kerosene. In the process TBP is decomposed into C4H8 and P2O5 thatwill corrode equipment and pipes. In order to convert P2O5 into calcium phosphate or pyrophosphate, andthen separate them from the pyrolysis reactor, calcium hydroxide and emulsifier solutions are added to the

  15. The genes that encode the gonococcal transferrin binding proteins, TbpB and TbpA, are differentially regulated by MisR under iron-replete and iron-depleted conditions. (United States)

    Kandler, Justin L; Acevedo, Rosuany Vélez; Dickinson, Mary Kathryne; Cash, Devin R; Shafer, William M; Cornelissen, Cynthia Nau


    Neisseria gonorrhoeae produces two transferrin binding proteins, TbpA and TbpB, which together enable efficient iron transport from human transferrin. We demonstrate that expression of the tbp genes is controlled by MisR, a response regulator in the two-component regulatory system that also includes the sensor kinase MisS. The tbp genes were up-regulated in the misR mutant under iron-replete conditions but were conversely down-regulated in the misR mutant under iron-depleted conditions. The misR mutant was capable of transferrin-iron uptake at only 50% of wild-type levels, consistent with decreased tbp expression. We demonstrate that phosphorylated MisR specifically binds to the tbpBA promoter and that MisR interacts with five regions upstream of the tbpB start codon. These analyses confirm that MisR directly regulates tbpBA expression. The MisR binding sites in the gonococcus are only partially conserved in Neisseria meningitidis, which may explain why tbpBA was not MisR-regulated in previous studies using this related pathogen. This is the first report of a trans-acting protein factor other than Fur that can directly contribute to gonococcal tbpBA regulation.

  16. Improved efficient routing strategy on two-layer complex networks (United States)

    Ma, Jinlong; Han, Weizhan; Guo, Qing; Zhang, Shuai; Wang, Junfang; Wang, Zhihao


    The traffic dynamics of multi-layer networks has become a hot research topic since many networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the traditional shortest path routing (SPR) protocol is susceptible to congestion on two-layer complex networks. In this paper, we propose an efficient routing strategy named improved global awareness routing (IGAR) strategy which is based on the betweenness centrality of nodes in the two layers. With the proposed strategy, the routing paths can bypass hub nodes of both layers to enhance the transport efficiency. Simulation results show that the IGAR strategy can bring much better traffic capacity than the SPR and the global awareness routing (GAR) strategies. Because of the significantly improved traffic performance, this study is helpful to alleviate congestion of the two-layer complex networks.

  17. Targeting TBP-associated factors in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Jennifer R Ribeiro


    Full Text Available As ovarian tumors progress, they undergo a process of dedifferentiation, allowing adaptive changes in growth and morphology that promote metastasis and chemoresistance. Herein, we outline a hypothesis that TATA-box binding protein (TBP associated factors (TAFs, which compose the RNA Polymerase II initiation factor, TFIID, contribute to regulation of dedifferentiation states in ovarian cancer. Numerous studies demonstrate that TAFs regulate differentiation and proliferation states; their expression is typically high in pluripotent cells and reduced upon differentiation. Strikingly, TAF2 exhibits copy number increases or mRNA overexpression in 73% of high grade serous ovarian cancers (HGSC. At the biochemical level, TAF2 directs TFIID to TATA-less promoters by contact with an Initiator element, which may lead to the deregulation of the transcriptional output of these tumor cells. TAF4, which is altered in 66% of HGSC, is crucial for the stability of the TFIID complex and helps drive dedifferentiation of mouse embryonic fibroblasts to induced pluripotent stem cells. Its ovary-enriched paralog, TAF4B, is altered in 26% of HGSC. Here, we show that Taf4b mRNA correlates with Cyclin D2 mRNA expression in human granulosa cell tumors. TAF4B may also contribute to regulation of tumor microenvironment due to its estrogen-responsiveness and ability to act as a cofactor for NFκB. Conversely, TAF9, a cofactor for p53 in regulating apoptosis, may act as a tumor suppressor in ovarian cancer, since it is downregulated or deleted in 98% of HGSC. We conclude that a greater understanding of mechanisms of transcriptional regulation that execute signals from oncogenic signaling cascades is needed in order to expand our understanding of the etiology and progression of ovarian cancer, and most importantly to identify novel targets for therapeutic intervention.

  18. Synchronization of Stochastic Two-Layer Geophysical Flows

    Institute of Scientific and Technical Information of China (English)

    HAN Yongqian


    In this paper, the two-layer quasigeostrophic flow model under stochastic wind forcing is considered. It is shown that when the layer depth or density difference across the layers tends to zero, the dynamics on both layers synchronizes to an averaged geophysical flow model.

  19. Linear waves in two-layer fluids over periodic bottoms

    NARCIS (Netherlands)

    Yu, J.; Maas, L.R.M.


    A new, exact Floquet theory is presented for linear waves in two-layer fluidsover a periodic bottom of arbitrary shape and amplitude. A method of conformaltransformation is adapted. The solutions are given, in essentially analytical form, forthe dispersion relation between wave frequency and general

  20. Linear waves in two-layer fluids over periodic bottoms

    NARCIS (Netherlands)

    Yu, Jie; Maas, L.R.M.


    A new, exact Floquet theory is presented for linear waves in two-layer fluids over a periodic bottom of arbitrary shape and amplitude. A method of conformal transformation is adapted. The solutions are given, in essentially analytical form, for the dispersion relation between wave frequency and gene

  1. Screening of TODGA/TBP/OK solvent mixtures for the grouped extraction of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jamie; Carrott, Michael J; Maher, Chris J; Mason, Chris; McLachlan, Fiona; Sarsfield, Mark J; Taylor, Robin J; Woodhead, Dave A [National Nuclear Laboratory, B170, Sellafield, Seascale, CUMBRIA, CA20 1PG (United Kingdom); Fox, O Danny, E-mail: [Nuclear Decommissioning Authority, Herdus House, Westlakes Science and Technology Park, Moor Row, CA24 3HU (United Kingdom)


    The solvent combination N,N,N'N'- tetraoctyl diglycolamide (TODGA)/tributyl phosphate (TBP)/odourless kerosene (OK) is examined as a potential solvent system for a Grouped Actinide Extraction (GANEX) process to separate all of the actinides from fission products when reprocessing spent nuclear fuel. A series of solvent extraction batch experiments were performed with a range of TODGA/TBP/OK solvent combinations to assess the sensitivity of distribution values for a number of key elements towards [TBP] (0 - 1.1M), [TODGA] (0.1-0.4M), [HNO{sub 3}] (0.1-5M) and heavy metal loading ([U] 0-200g/l). There is little impact on D{sub Am} or D{sub Eu} across the solvent range and no influence from U loading. Excellent D{sub Np} values (> 10) are observed, increasing with increasing [TODGA], with [TBP] having little influence. Such high D{sub Np} values may obviate the need for preconditioning of dissolved fuel feeds to control Np routing. High D{sub Tc} values are found even at 5M HNO{sub 3}, therefore Tc is expected to remain in the solvent phase. Both Pu(III) and Pu(IV) are readily extracted with D{sub Pu(III)} > D{sub Pu(IV)}. Uranium is extracted by both TBP and TODGA and TBP is shown to effectively compete with TODGA for uranium coordination sites. Third phase formation occurs at high [U] loading and [HNO{sub 3}] but is suppressed by increasing [TBP].

  2. Kinetics of reactive extraction of Nd from nd203 with tbp-hno3 complex in supercritical carbon dioxide%在超临界二氧化碳中用TBP-HN03络合剂反应萃取Nd203中Nd的动力学

    Institute of Scientific and Technical Information of China (English)

    朱礼洋; 段五华; 徐景明; 朱永贝睿


    The process based on supercriticaI fluid extraction for reprocessing Of the spent nuclear fuel has some remarkable advantages over the plutonium-uranium extraction(PUREX) process.Especially,it can minimize the generation of secondary waste.Dynamic reactive extraction of neodymium oxide(Nd2 O3)in supercritical carbon dioxide(SC-CO2)containing tri-n-butyl phosphate-nitric acid(TBP-HNO3)complex was investigated.Temperature showed a positive effect on the extraction efficiency,while pressure showed a negative effect when the unsaturated TBP-HNO3 complex was employed for the dynamic reactive extraction of Nd2O3 in SC-CO2.Both temperature and pressure effects indicated that the kinetic proccss of the reactive extraction was controlled by the chemical reaction.A kinetic model was proposed to describe the extraction process.

  3. Thioredoxin Binding Protein-2 Regulates Autophagy of Human Lens Epithelial Cells under Oxidative Stress via Inhibition of Akt Phosphorylation (United States)

    Yao, Ke; Zhang, Yidong; Chen, Guangdi; Lai, Kairan; Yin, Houfa


    Oxidative stress plays an essential role in the development of age-related cataract. Thioredoxin binding protein-2 (TBP-2) is a negative regulator of thioredoxin (Trx), which deteriorates cellular antioxidant system. Our study focused on the autophagy-regulating effect of TBP-2 under oxidative stress in human lens epithelial cells (LECs). Human lens epithelial cells were used for cell culture and treatment. Lentiviral-based transfection system was used for overexpression of TBP-2. Cytotoxicity assay, western blot analysis, GFP/mCherry-fused LC3 plasmid, immunofluorescence, and transmission electronic microscopy were performed. The results showed that autophagic response of LECs with increased LC3-II, p62, and GFP/mCherry-LC3 puncta (P < 0.01) was induced by oxidative stress. Overexpression of TBP-2 further strengthens this response and worsens the cell viability (P < 0.01). Knockdown of TBP-2 attenuates the autophagic response and cell viability loss induced by oxidative stress. TBP-2 mainly regulates autophagy in the initiation stage, which is mTOR-independent and probably caused by the dephosphorylation of Akt under oxidative stress. These findings suggest a novel role of TBP-2 in human LECs under oxidative stress. Oxidative stress can cause cell injury and autophagy in LECs, and TBP-2 regulates this response. Hence, this study provides evidence regarding the role of TBP-2 in lens and the possible mechanism of cataract development. PMID:27656263

  4. Treatment of low level radioactive liquid waste containing appreciable concentration of TBP degraded products. (United States)

    Valsala, T P; Sonavane, M S; Kore, S G; Sonar, N L; De, Vaishali; Raghavendra, Y; Chattopadyaya, S; Dani, U; Kulkarni, Y; Changrani, R D


    The acidic and alkaline low level radioactive liquid waste (LLW) generated during the concentration of high level radioactive liquid waste (HLW) prior to vitrification and ion exchange treatment of intermediate level radioactive liquid waste (ILW), respectively are decontaminated by chemical co-precipitation before discharge to the environment. LLW stream generated from the ion exchange treatment of ILW contained high concentrations of carbonates, tributyl phosphate (TBP) degraded products and problematic radio nuclides like (106)Ru and (99)Tc. Presence of TBP degraded products was interfering with the co-precipitation process. In view of this a modified chemical treatment scheme was formulated for the treatment of this waste stream. By mixing the acidic LLW and alkaline LLW, the carbonates in the alkaline LLW were destroyed and the TBP degraded products got separated as a layer at the top of the vessel. By making use of the modified co-precipitation process the effluent stream (1-2 μCi/L) became dischargeable to the environment after appropriate dilution. Based on the lab scale studies about 250 m(3) of LLW was treated in the plant. The higher activity of the TBP degraded products separated was due to short lived (90)Y isotope. The cement waste product prepared using the TBP degraded product was having good chemical durability and compressive strength. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Pattern Synchronization in a Two-Layer Neuronal Network

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-Juan; LU Qi-Shao


    Pattern synchronization in a two-layer neuronal network is studied.For a single-layer network of Rulkov map neurons,there are three kinds of patterns induced by noise.Additive noise can induce ordered patterns at some intermediate noise intensities in a resonant way;however,for small and large noise intensities there exist excitable patterns and disordered patterns,respectively.For a neuronal network coupled by two single-layer networks with noise intensity differences between layers,we find that the two-layer network can achieve synchrony as the interlayer coupling strength increases.The synchronous states strongly depend on the interlayer coupling strength and the noise intensity difference between layers.

  6. Training two-layered feedforward networks with variable projection method. (United States)

    Kim, C T; Lee, J J


    The variable projection (VP) method for separable nonlinear least squares (SNLLS) is presented and incorporated into the Levenberg-Marquardt optimization algorithm for training two-layered feedforward neural networks. It is shown that the Jacobian of variable projected networks can be computed by simple modification of the backpropagation algorithm. The suggested algorithm is efficient compared to conventional techniques such as conventional Levenberg-Marquardt algorithm (LMA), hybrid gradient algorithm (HGA), and extreme learning machine (ELM).

  7. Electromagnetic Scattering in a Two-layered Medium

    Institute of Scientific and Technical Information of China (English)

    FENG LI-XIN; LI YUAN; Ma Fu-ming


    The object of this paper is to investigate the three-dimensional electro-magnetic scattering problems in a two-layered background medium.These problems have an important application in today's technology,such as to detect objects that are buried in soil.Here,we model both the exterior impedance problem and the inhomogeneous medium problem in R3.We establish uniqueness and existence for the solution of the two scattering problems,respectively.

  8. The Distribution of Plutonium(Ⅲ,Ⅳ) Nitrate Between Dilute TBP/OK and Aqueous Phase

    Institute of Scientific and Technical Information of China (English)


    The distribution of plutonium (Ⅲ, Ⅳ) nitrate between dilute TBP/OK and aqueous phase is systematically investigated. On the basis of the preparation and stabilization of Pu(Ⅲ, Ⅳ), the influences of the concentration of HNO3, Al(NO3)3, TBP and UO2(NO3)2 on the distribution ratio of them are studied at 25℃. The results indicate that the distribution ratio of Pu(Ⅳ) has a maximum while that of Pu(Ⅲ) increases with the concentration of HNO3. The distribution ratio of Pu(Ⅲ, Ⅳ) increases along with the concentration of Al(NO3)3 and TBP. The extraction reaction

  9. Coextraction of uranium(VI) form nitric acid solutions by N,N—diethyldecanamide and TBP

    Institute of Scientific and Technical Information of China (English)

    SunGuo-Xin; SunSi-Xiu; 等


    The partition of uranium(VI) between nitric acid and N,N-diethydecanamide,C9H19CON(C2H5)2,(DEDEA)in kerosene has been investigated at various concentrations of nitric acid,extractant and slating -out agent LiNO3.The mechanism of extraction is discussed in the light of the results obtained.The effect of TBP on the extraction of uranium(VI) with DEDEA has also been considered.There is apparent synergism between these two extractants at low concentration of TBP;however,at higher concentration,distributioin ratio decreases.

  10. Singlet Ground State Magnetism: III Magnetic Excitons in Antiferromagnetic TbP

    DEFF Research Database (Denmark)

    Knorr, K.; Loidl, A.; Kjems, Jørgen


    The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.......The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined....

  11. Two-Layer Feedback Neural Networks with Associative Memories

    Institute of Scientific and Technical Information of China (English)

    WU Gui-Kun; ZHAO Hong


    We construct a two-layer feedback neural network by a Monte Carlo based algorithm to store memories as fixed-point attractors or as limit-cycle attractors. Special attention is focused on comparing the dynamics of the network with limit-cycle attractors and with fixed-point attractors. It is found that the former has better retrieval property than the latter. Particularly, spurious memories may be suppressed completely when the memories are stored as a long-limit cycle. Potential application of limit-cycle-attractor networks is discussed briefly.

  12. Tidal modulation of two-layer hydraulic exchange flows

    Directory of Open Access Journals (Sweden)

    L. M. Frankcombe


    Full Text Available Time-dependent, two layer hydraulic exchange flow is studied using an idealised shallow water model. It is found that barotropic time-dependent perturbations, representing tidal forcing, increase the baroclinic exchange flux above the steady hydraulic limit, with flux increasing monotonically with tidal amplitude (measured either by height or flux amplitude over a tidal period. Exchange flux also depends on the non-dimensional tidal period, γ, which was introduced by Helfrich (1995. Resonance complicates the relationship between exchange flux and height amplitude, but, when tidal strength is characterised by flux amplitude, exchange flux is a monotonic function of γ.

  13. Baroclinic instability in the two-layer model. Interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Egger, Joseph [Meteorological Inst., Univ. of Munich (Germany)


    Two new interpretations of the wellknown instability criterion of the two-layer model of baroclinic instability are given whereby also a slight generalization of this model is introduced by admitting an interface on top with a reduced gravity g. It is found that instability sets in when the horizontal potential temperature advection by the barotropic mode becomes more important than the vertical temperature advection due to this mode. The second interpretation is based on potential vorticity (PV) thinking. Instability implies a dominance of the vertical PV coupling coefficient compared to horizontal mean state PV advection generated at the same level. The interface damps with decreasing g. (orig.)

  14. Interference testing of a two-layer commingled reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Onur, M.; Reynolds, A.C. (Tulsa Univ., OK (USA))


    A two-well system in an infinite-acting, commingled, two-layer reservoir is considered. One well, the active well, is produced at a constant total rate, and the second well, the observation well, is shut in at all times. An analytical solution in Laplace space is presented, and the parametric groups that uniquely determine the pressure and rate solutions are identified. Results regarding crossflow through the observation well are presented. Conditions under which the line-source solution can be used to analyze observations-well pressure data are delineated.

  15. Spatial frequency domain spectroscopy of two layer media (United States)

    Yudovsky, Dmitry; Durkin, Anthony J.


    Monitoring of tissue blood volume and oxygen saturation using biomedical optics techniques has the potential to inform the assessment of tissue health, healing, and dysfunction. These quantities are typically estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in superficial tissue such as the skin can be confounded by the strong absorption of melanin in the epidermis. Furthermore, epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. This study describes a technique for decoupling the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. An artificial neural network was used to map input optical properties to spatial frequency domain diffuse reflectance of two layer media. Then, iterative fitting was used to determine the optical properties from simulated spatial frequency domain diffuse reflectance. Additionally, an artificial neural network was trained to directly map spatial frequency domain reflectance to sets of optical properties of a two layer medium, thus bypassing the need for iteration. In both cases, the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis were determined independently. The accuracy and efficiency of the iterative fitting approach was compared with the direct neural network inversion.

  16. Nonlinear topographic effects in two-layer flows

    Directory of Open Access Journals (Sweden)

    Peter George Baines


    Full Text Available We consider the nature of non-linear flow of a two-layer fluid with a rigid lid over a long obstacle, such that the flow may be assumed to be hydrostatic. Such flows can generate hydraulic jumps upstream, and the model uses a new model of internal hydraulic jumps, which results in corrections to flows that have been computed using earlier models of jumps that are now known to be incorrect. The model covers the whole range of ratios of the densities of the two fluids, and is not restricted to the Boussinesq limit. The results are presented in terms of flow types in various regions of a Froude number-obstacle height (F0 – Hm diagram, in which the Froude number F0 is based on the initial flow conditions. When compared with single-layer flow, and some previous results with two layers, some surprising and novel patterns emerge on these diagrams. Specifically, in parts of the diagram where the flow may be supercritical (F0 > 1, there are regions where hysteresis may occur, implying that the flow may have two and sometimes three multiple flow states for the same conditions (i.e. values of F0 and Hm.

  17. Two-Layer Elastographic 3-D Traction Force Microscopy (United States)

    Álvarez-González, Begoña; Zhang, Shun; Gómez-González, Manuel; Meili, Ruedi; Firtel, Richard A.; Lasheras, Juan C.; Del Álamo, Juan C.


    Cellular traction force microscopy (TFM) requires knowledge of the mechanical properties of the substratum where the cells adhere to calculate cell-generated forces from measurements of substratum deformation. Polymer-based hydrogels are broadly used for TFM due to their linearly elastic behavior in the range of measured deformations. However, the calculated stresses, particularly their spatial patterns, can be highly sensitive to the substratum’s Poisson’s ratio. We present two-layer elastographic TFM (2LETFM), a method that allows for simultaneously measuring the Poisson’s ratio of the substratum while also determining the cell-generated forces. The new method exploits the analytical solution of the elastostatic equation and deformation measurements from two layers of the substratum. We perform an in silico analysis of 2LETFM concluding that this technique is robust with respect to TFM experimental parameters, and remains accurate even for noisy measurement data. We also provide experimental proof of principle of 2LETFM by simultaneously measuring the stresses exerted by migrating Physarum amoeboae on the surface of polyacrylamide substrata, and the Poisson’s ratio of the substrata. The 2LETFM method could be generalized to concurrently determine the mechanical properties and cell-generated forces in more physiologically relevant extracellular environments, opening new possibilities to study cell-matrix interactions.

  18. Design and analysis of two-layer anonymous communication system

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-ping; WANG Jian-xin


    A new architecture for scalable anonymous communication system(SACS) was proposed. The users were divided into several subgroups managed by different sub-blenders, and all sub-blenders were managed by the main-blender using two layers management scheme. The identity information of members are distributed on different sub-blenders, which makes each member keep much less information and network overload greatly reduce. The anonymity and the overhead of the new scheme were analyzed and compared with that of Crowds, which shows the cost of storage and network overhead for the new scheme largely decreases while the anonymity is little degraded. The experiment results also show that the new system architecture is well scalable. The ratio of management cost of SACS to that of Crowds is about 1:25 while the value of P(I|H1+) only increases by 0.001-0.020, which shows that SACS keeps almost the same anonymity with Crowds.

  19. Synergistic extraction of U(VI) and Th(IV) from nitric acid media with HBMPPT and TBP in toluene

    Institute of Scientific and Technical Information of China (English)

    YUShaoning; BAOBorong


    The sysnergistic extraction of U(VI)and Th(IV) from nitric acid solution by HBMPPT(4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione) and TBP( tributylphosphate)in toluene was studied.The extraction ability of HBMPPT for U(VI) and Th(IV) was not so high.but when a little TBP was added in,the ability to extract U(VI) and Th(IV) was improved.The extracted complexes may be presented as UO2NO3.BMPPT.TBP and UO2(BMPPT)2.TBP for U(VI).and Th(NO3)3.BMPPT.TBP and Th(NO3)2(BMPPT)2.TBP for Th(IV),respectively,in the synergistic extraction system.The synergistic effect of HBMPPT and TBP makes the separation cofeeicient of U(VI)/Th (IV) or U(VI)/Eu(Ⅲ) reach a high value.

  20. Quantify Water Extraction by TBP/Dodecane via Molecular Dynamics Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Khomami, Bamin [Univ. of Tennessee, Knoxville, TN (United States); Cui, Shengting [Univ. of Tennessee, Knoxville, TN (United States); de Almeida, Valmor F. [Oak Ridge National Lab., Oak Ridge, TN (United States); Felker, Kevin [Oak Ridge National Lab., Oak Ridge, TN (United States)


    The purpose of this project is to quantify the interfacial transport of water into the most prevalent nuclear reprocessing solvent extractant mixture, namely tri-butyl- phosphate (TBP) and dodecane, via massively parallel molecular dynamics simulations on the most powerful machines available for open research. Specifically, we will accomplish this objective by evolving the water/TBP/dodecane system up to 1 ms elapsed time, and validate the simulation results by direct comparison with experimentally measured water solubility in the organic phase. The significance of this effort is to demonstrate for the first time that the combination of emerging simulation tools and state-of-the-art supercomputers can provide quantitative information on par to experimental measurements for solvent extraction systems of relevance to the nuclear fuel cycle. Results: Initially, the isolated single component, and single phase systems were studied followed by the two-phase, multicomponent counterpart. Specifically, the systems we studied were: pure TBP; pure n-dodecane; TBP/n-dodecane mixture; and the complete extraction system: water-TBP/n-dodecane two phase system to gain deep insight into the water extraction process. We have completely achieved our goal of simulating the molecular extraction of water molecules into the TBP/n-dodecane mixture up to the saturation point, and obtained favorable comparison with experimental data. Many insights into fundamental molecular level processes and physics were obtained from the process. Most importantly, we found that the dipole moment of the extracting agent is crucially important in affecting the interface roughness and the extraction rate of water molecules into the organic phase. In addition, we have identified shortcomings in the existing OPLS-AA force field potential for long-chain alkanes. The significance of this force field is that it is supposed to be optimized for molecular liquid simulations. We found that it failed for dodecane and

  1. Synergistic extraction of U(VI) and Th(IV) from nitric acid media withHBMPPT and TBP in toluene

    Institute of Scientific and Technical Information of China (English)


    The synergistic extraction of U(VI) and Th(IV) from nitric acid solutionby HBMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione) andTBP (tributylphosphate ) in toluene was studied. The extraction abilityof HBMPPT for U(VI) and Th(IV) was not so high, but when a little TBP was added in, theability to extract U(VI) and Th(IV) was improved. The extracted complexes may be presented as UO2NO3.BMPPT.TBP and UO2(BMPPT)2 .TBP for U(VI), and Th(NO3)3.BMPPT.TBP andTh(NO3)2 (BMPPT)2.TBP for Th(IV),respectively, in the synergisticextraction system. The synergistic effect of HBMPPT and TBP makes the separationcoefficient of U(VI) /Th(IV) or U(VI)/Eu(III) reach a high value.

  2. In vivo spatial frequency domain spectroscopy of two layer media (United States)

    Yudovsky, Dmitry; Nguyen, John Quan M.; Durkin, Anthony J.


    Monitoring of tissue blood volume and local oxygen saturation can inform the assessment of tissue health, healing, and dysfunction. These quantities can be estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in skin can be confounded by the strong absorption of melanin in the epidermis and epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. Therefore, a method is desired that decouples the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. A previously developed inverse method based on a neural network forward model was applied to simulated spatial frequency domain reflectance of skin for multiple wavelengths in the near infrared. It is demonstrated that the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis can be determined independently and with minimal coupling. Then, the same inverse method was applied to reflectance measurements from a tissue simulating phantom and in vivo human skin. Oxygen saturation and total hemoglobin concentrations were estimated from the volar forearms of weakly and strongly pigmented subjects using a standard homogeneous model and the present two layer model.

  3. Radiolysis of TBP in the presence of plutonium and uranium. [Gamma radiation; alpha sources

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, I.A.; Kermanov, N.V.; Vladimirova, M.V.


    Using the methods of potentiometry, spectrophotometry and chromatography the yields of TBP decomposition products during ..cap alpha..- and ..gamma..-radiolysis in the two-phase system of 30% TBP in n-paraffin-3.0 mol/l HNO/sub 3/ in the presence of Pusup((4)) (10/sup -3/-10/sup -1/ mol/l) and Usup((6)) (0.01-0.3 mol/l) have been determined. Formation yields of Pusup((4)) complexes with dibutylphosphoric acid (DBPA) and monobutylphosphoric (MBPA) acid in the two-phase system studied are found. It is shown that, with an increase in (Me) from 0.01 to 0.3 mol/l, the G of DBPA increases from 1.9 to 3.0, and the G of MBPA - from 0.3 to 0.45 molecules/100 eV. Radiative gas evolution composition and yields of gaseous radiolysis products of the organic phase have been studied. Kinetics of DBPA formation in the presence of plutonium is considered. Constants of DBPA formation and decomposition rates are determined. On the basis of experimental data the maximum yield of the TBP decomposition is calculated to be equal to approximately 6.0 molecules/100 eV.

  4. Influence of alpha and gamma radiolysis on Pu retention in the solvent TBP/kerosene

    Directory of Open Access Journals (Sweden)

    Gao Yang


    Full Text Available In light of the issue of radiolysis of the solvent system in PUREX process, alpha and gamma radiation stability of tributyl phosphate (TBP/kerosene (OK have been studied in this paper, in which 238Pu dissolved in the organic phase and 60Co are selected as alpha and gamma irradiation sources, respectively. The amount of the degradation products not easily removed after the washing process has been measured by the plutonium retention. The effects of the absorbed dose, the TBP volume fraction, the cumulative absorbed dose and the presence of UO2 2+ and Zr4+ on the radiolysis of the solvents have been investigated. The results have indicated that the Pu retention increases with the increase of the absorbed dose after alpha or gamma irradiation, and is larger for the solvent containing less TBP. There is competition between UO2 2+ and Pu4+ to complex with the degradation products, and Zr4+ accelerates the radiolysis of the system.

  5. Designing Two-Layer Optical Networks with Statistical Multiplexing (United States)

    Addis, B.; Capone, A.; Carello, G.; Malucelli, F.; Fumagalli, M.; Pedrin Elli, E.

    The possibility of adding multi-protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question that arises is whether it is suitable to have MPLS nodes just at the edge of the network to collect packet traffic from users, or also to introduce MPLS facilities on a subset of the core nodes in order to exploit packet switching flexibility and multiplexing, thus providing induction of a better bandwidth allocation. In this article, we address this complex decisional problem with the support of a mathematical programming approach. We consider two-layer networks where MPLS is overlaid on top of transport networks-synchronous digital hierarchy (SDH) or wavelength division multiplexing (WDM)-depending on the required link speed. The discussions' decisions take into account the trade-off between the cost of adding MPLS support in the core nodes and the savings in the link bandwidth allocation due to the statistical multiplexing and the traffic grooming effects induced by MPLS nodes. The traffic matrix specifies for each point-to-point request a pair of values: a mean traffic value and an additional one. Using this traffic model, the effect of statistical multiplexing on a link allows the allocation of a capacity equal to the sum of all the mean values of the traffic demands routed on the link and only the highest additional one. The proposed approach is suitable to solve real instances in reasonable time.

  6. The synergic extraction of uranium (Ⅵ) with tri-n-butyl phosphate (TBP) and petroleum sulfoxides(PSO)/benzene

    Institute of Scientific and Technical Information of China (English)


    The synergistic extraction of uranium (Ⅵ) from nitric acid aqueous solution with a mixture of tri-n-butyl phosphate (TBP) and petroleum sulfoxides(PSO) in benzene was studied. It has been found that the maximum synergistic extraction effect occurs where the molar ratio of PSO to TBP is one to two. The composition of the complex of synergistic extraction is UO2(NO3)2.TB P.PSO. The formation constant of the complex KTp=57.44.

  7. Promotion of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on titanium

    Directory of Open Access Journals (Sweden)

    Xin-Yu Li


    Full Text Available AIM:To investigate the influence of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on titanium (Ti surface.METHODS:The chimeric peptide RKLPDAPRGDN (minTBP-1-PRGDN was synthesized by connecting RKLPDA (minTBP-1 to the N-terminal of PRGDN , the influence of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on Ti surface were tested using PRGDN and minTBP-1as controls. The keratocytes attached to the surface of Ti were either stained with FITC-labeled phalloidin and viewed with fluorescence microscope or quantified with alamar Blue method. The proliferation of keratocytes on Ti were quantified with 3-(4,5-dim- ethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide up-taking methods. The secretion of type I collagen were determined using an ELISA kit.RESULTS:The results showed that minTBP-1-PRGDN at a concentration of 100ng/mL was the most potent peptide to enhance the attachment of human keratocytes to the surface of Ti (1.40±0.03 folds, P=0.003, to promote the proliferation (1.26±0.05 folds, P=0.014 and the synthesis of type I collagen (1.530±0.128, P=0.008. MinTBP-1 at the same concentration could only promote the attachment (1.13±0.04 folds, P=0.020 and proliferation(1.15±0.06 folds, P=0.021, while PRGDN had no significant influence (P>0.05.CONCLUSION:Our data shows that the novel chimeric peptide minTBP-1-PRGDN could promote the attachment, proliferation and type I collagen synthesis of human keratocytes on the surface of Ti.

  8. Measurement of tributyl phosphate (TBP) in groundwater at a legacy radioactive waste site and its possible role in contaminant mobilisation. (United States)

    Rowling, Brett; Kinsela, Andrew S; Comarmond, M Josick; Hughes, Catherine E; Harrison, Jennifer J; Johansen, Mathew P; Payne, Timothy E


    At many legacy radioactive waste sites, organic compounds have been co-disposed, which may be a factor in mobilisation of radionuclides at these sites. Tri-butyl phosphate (TBP) is a component of waste streams from the nuclear fuel cycle, where it has been used in separating actinides during processing of nuclear fuels. Analyses of ground waters from the Little Forest Legacy Site (LFLS) in eastern Australia were undertaken using solid-phase extraction (SPE) followed by gas chromatographic mass spectrometry (GCMS). The results indicate the presence of TBP several decades after waste disposal, with TBP only being detected in the immediate vicinity of the main disposal area. TBP is generally considered to degrade in the environment relatively rapidly. Therefore, it is likely that its presence is due to relatively recent releases of TBP, possibly stemming from leakage due to container degradation. The ongoing presence and solubility of TBP has the potential to provide a mechanism for nuclide mobilisation, with implications for long term management of LFLS and similar legacy waste sites. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  9. Deficiency of thioredoxin binding protein-2 (TBP-2 enhances TGF-β signaling and promotes epithelial to mesenchymal transition.

    Directory of Open Access Journals (Sweden)

    So Masaki

    Full Text Available BACKGROUND: Transforming growth factor beta (TGF-β has critical roles in regulating cell growth, differentiation, apoptosis, invasion and epithelial-mesenchymal transition (EMT of various cancer cells. TGF-β-induced EMT is an important step during carcinoma progression to invasion state. Thioredoxin binding protein-2 (TBP-2, also called Txnip or VDUP1 is downregulated in various types of human cancer, and its deficiency results in the earlier onset of cancer. However, it remains unclear how TBP-2 suppresses the invasion and metastasis of cancer. PRINCIPAL FINDINGS: In this study, we demonstrated that TBP-2 deficiency increases the transcriptional activity in response to TGF-β and also enhances TGF-β-induced Smad2 phosphorylation levels. Knockdown of TBP-2 augmented the TGF-β-responsive expression of Snail and Slug, transcriptional factors related to TGF-β-mediated induction of EMT, and promoted TGF-β-induced spindle-like morphology consistent with the depletion of E-Cadherin in A549 cells. CONCLUSIONS/SIGNIFICANCE: Our results indicate that TBP-2 deficiency enhances TGF-β signaling and promotes TGF-β-induced EMT. The control of TGF-β-induced EMT is critical for the inhibition of the invasion and metastasis. Thus TBP-2, as a novel regulatory molecule of TGF-β signaling, is likely to be a prognostic indicator or a potential therapeutic target for preventing tumor progression.

  10. Phylogenetic Analysis of por and tbpB Genetic Variations and Their Association with Evolution of Neisseria Gonorrhoeae%淋球菌por,tbpB基因序列变异和系统进化探讨

    Institute of Scientific and Technical Information of China (English)

    黄美容; 黄健; 闵迅; 杨昌伟; 张绍基; 颜利江


    目的 分析遵义地区淋球菌por,tbpB基因序列变异及系统进化关系.方法 对淋球菌por,tbpB基因进行测序鉴定,利用NG-MAST分型法对por,tbpB基因进行比对编号.用MEGA5.22软件中的邻接法构建系统发育树,并以Kimura 2-parameter模型计算序列间的遗传距离;Felsenstein法计算同义替换率(dS)和非同义替换率(dN).以RDP3软件对por,tbpB基因中的基因重组事件进行分析.结果 65株淋球菌共鉴定出19种por基因型和22种tbpB基因型.19种por基因型被划分为2个进化簇群,基因间平均遗传距离0.09.22种tbB基因型被划分为3个进化簇群,基因间平均遗传距离0.13.por,tbpB基因的dN<dS.在tbpB基因中检测出8个基因重组事件,而por基因仅有1个.结论 本地区淋球菌por基因与tbpB基因的进化速度与方式存在一定差异,其中tbpB基因主要以基因重组的方式参与进化,por基因则可能以突变或缺失的方式参与进化.纯选择作用是维持本地区por,tbpB基因多态性的重要机制.

  11. Extraction of Gentamycin from Fermentation Filtrate with NaDEHP-TBP -Isooctane Reverse Micelle%NaDEHP-TBP-异辛烷反胶束萃取庆大霉素的研究

    Institute of Scientific and Technical Information of China (English)

    李夏兰; 翁连进; 蔡婀娜; 陈培钦



  12. Np(Ⅳ)在稀TBP/煤油与水相间的分配%Extraction of Np(Ⅳ) by Dilute TBP/kerosene

    Institute of Scientific and Technical Information of China (English)

    贾永芬; 朱志瑄; 罗方祥; 胡景炘; 叶国安


    研究了25 ℃下HNO3、Al(NO3)3和U(Ⅵ)浓度对5 %TBP/煤油萃取Np(Ⅳ)分配比的影响,求出了相应条件下的经验公式.考察了TBP浓度对Np(Ⅳ)萃取的影响,Np(Ⅳ)以Np(NO3)4·2TBP形式被萃入有机相,25 ℃下TBP萃取Np(Ⅳ)的反应平衡常数Kex=2.60 mol-6·L6.考察了温度对Np(Ⅳ)萃取分配的影响,该反应为吸热反应,反应的焓变ΔH=1.18 kJ/mol,25 ℃下萃取反应的自由能ΔG=-2.37 kJ/mol.

  13. Reflected light intensity profile of two-layer tissues: phantom experiments. (United States)

    Ankri, Rinat; Taitelbaum, Haim; Fixler, Dror


    Experimental measurements of the reflected light intensity from two-layer phantoms are presented. We report, for the first time, an experimental observation of a typical reflected light intensity behavior for the two-layer structure characterized by two different slopes in the reflected light profile of the irradiated tissue. The point in which the first slope changes to the second slope, named as the crossover point, depends on the upper layer thickness as well as on the ratio between the absorption coefficients of the two layers. Since similar experiments from one-layer phantoms present a monotonic decay behavior, the existence and the location of the crossover point can be used as a diagnostic fingerprint for two-layer tissue structures. This pertains to two layers with greater absorptivity in the upper layer, which is the typical biological case in tissues like skin.


    Directory of Open Access Journals (Sweden)

    Baghdad Medjahed


    Full Text Available The sorption of copper (II present in an aqueous media using a supported liquid membrane (SLM by chloride tri-N-octylmethylammonium (Aliquat 336 and Tri-n-butylphosphate (TBP from molar ratio 1:1, with polytetrafluoroethylene (PTFE as a membrane support was studied. The effects of various parameters as initial pH, KSCN concentration and ammonium acetate concentration on the extraction yield were carried out. By a calculation program using CHEAQS V. L20.1, the determination of the percentages of the present species before and after extraction were given, in aqueous medium and on the membrane to be able to determine the relation between the nature of the extracted species and the extraction yield. The 23 factorial design achieve the best conditions of recovery procedure. The recovery of copper (II is almost quantitative (94 %, in one step.

  15. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    National Research Council Canada - National Science Library

    E. Ramdan; N. M. Nor; K. Ramar


    Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode...

  16. Extraction equilibria of trimellitic and [1,1'-Biphenyl]-2,2'-dicarboxylic Acid with 1-Octanol, 50%TBP, and 10%TRPO in Kerosene%正辛醇、50%TBP/煤油和10%TRPO/煤油对偏苯三甲酸和2,2'-联苯二甲酸的萃取平衡

    Institute of Scientific and Technical Information of China (English)

    周智勇; 秦炜; 戴猷元


    To explore the feasibility of extracting aromatic acid products from oxidizing coal, two aromatic acids, trimellitic and [1,1'-biphenyl]-2,2'-dicarboxylic acid, were selected as the solutes, and the extraction equilibrium of the acids were studied with 1-octanol, 50% tributyl phosphate (TBP) in kerosene, and 10% trialkylphosphine oxide (TRPO) in kerosene. The results showed that the degree of extraction of [1,1'-biphenyl]-2,2'-dicarboxylic acid was larger than that of trimellitic acid for all of the solvent, and the extraction capacity with TRPO is more effective than the one with TBP. The extraction behavior of aromatic polyacid is different from that of carboxylic acid, and the reactive extraction function of aromatic acids with TBP and TRPO is not as effective as that of carboxylic acid. 1-octanol could be used to remove [1,1'-biphenyl]-2,2'-dicarboxylic acid from the mixture of trimellitic acid and [1,1'-biphenyl]-2,2'-dicarboxylic acid. Because the weak hydrogen bond association exists between -OH in 1-octanol and -COOH in aromatic acid, the extractive selectivity of [1,1'-biphenyl]-2,2'-dicarboxylic to trimellitic acid depends on the stoichiometric ratio.

  17. Study on Gold(Ⅰ) Solvent Extraction from Alkaline Cyanide Solution by TBP with Addition of Surfactant

    Institute of Scientific and Technical Information of China (English)


    The new solvent extraction system for gold(Ⅰ) from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organic phase, molar ratio of CPB∶Au(CN)2-, extraction time, aqueous/organic phase ratio, different initial gold concentration, equilibrium temperature, different diluent, different types of extractants and surfactants etc., was inspected. The results show that gold(Ⅰ) can be extracted quantitatively by controlling the quantity of surfactant (CPB); both the equilibrium pH and diluent hardly influence percent extraction. Gold(Ⅰ) percent extraction reaches more than 98% under the optimal experimental conditions. 30% vol TBP diluted by sulphonating kerosene can load gold(Ⅰ) to rather high levels. Loading capacity is in excess of 38 g/L. The extraction mechanism is discussed and the overall extraction reaction is deduced.

  18. Characterization, Leaching, and Filtration Testing for Tributyl Phosphate (TBP, Group 7) Actual Waste Sample Composites

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Matthew K.; Billing, Justin M.; Blanchard, David L.; Buck, Edgar C.; Casella, Amanda J.; Casella, Andrew M.; Crum, J. V.; Daniel, Richard C.; Draper, Kathryn E.; Fiskum, Sandra K.; Jagoda, Lynette K.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Shimskey, Rick W.; Snow, Lanee A.; Swoboda, Robert G.


    .A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. The actual waste-testing program included homogenizing the samples by group, characterizing the solids and aqueous phases, and performing parametric leaching tests. The tributyl phosphate sludge (TBP, Group 7) is the subject of this report. The Group 7 waste was anticipated to be high in phosphorus as well as aluminum in the form of gibbsite. Both are believed to exist in sufficient quantities in the Group 7 waste to address leaching behavior. Thus, the focus of the Group 7 testing was on the removal of both P and Al. The waste-type definition, archived sample conditions, homogenization activities, characterization (physical, chemical, radioisotope, and crystal habit), and caustic leaching behavior as functions of time, temperature, and hydroxide concentration are discussed in this report. Testing was conducted according to TP-RPP-WTP-467.

  19. TBP binding-induced folding of the glucocorticoid receptor AF1 domain facilitates its interaction with steroid receptor coactivator-1.

    Directory of Open Access Journals (Sweden)

    Shagufta H Khan

    Full Text Available The precise mechanism by which glucocorticoid receptor (GR regulates the transcription of its target genes is largely unknown. This is, in part, due to the lack of structural and functional information about GR's N-terminal activation function domain, AF1. Like many steroid hormone receptors (SHRs, the GR AF1 exists in an intrinsically disordered (ID conformation or an ensemble of conformers that collectively appears to be unstructured. The GR AF1 is known to recruit several coregulatory proteins, including those from the basal transcriptional machinery, e.g., TATA box binding protein (TBP that forms the basis for the multiprotein transcription initiation complex. However, the precise mechanism of this process is unknown. We have earlier shown that conditional folding of the GR AF1 is the key for its interactions with critical coactivator proteins. We hypothesize that binding of TBP to AF1 results in the structural rearrangement of the ID AF1 domain such that its surfaces become easily accessible for interaction with other coactivators. To test this hypothesis, we determined whether TBP binding-induced structure formation in the GR AF1 facilitates its interaction with steroid receptor coactivator-1 (SRC-1, a critical coactivator that is important for GR-mediated transcriptional activity. Our data show that stoichiometric binding of TBP induces significantly higher helical content at the expense of random coil configuration in the GR AF1. Further, we found that this induced AF1 conformation facilitates its interaction with SRC-1, and subsequent AF1-mediated transcriptional activity. Our results may provide a potential mechanism through which GR and by large other SHRs may regulate the expression of the GR-target genes.

  20. Recombinant transferrin binding protein A (rTbpA) fragments of Pasteurella multocida serogroup B:2 provide variable protection following homologous challenge in mouse model. (United States)

    Shivachandra, Sathish Bhadravati; Yogisharadhya, Revanaiah; Kumar, Abhinendra; Mohanty, Nihar Nalini; Nagaleekar, Viswas Konasagara


    Transferrin binding protein A (TbpA), an iron acquisition surface protein that also acts as virulence factor, is widely distributed among strains of Pasteurella multocida. In the present study, a total of seven clones of TbpA fragments (39D to F777; 39D to Q697; 188V to F777; 188V to Q697; 39D to P377; 188V to P377 and 39D to F187) belonging to P. multocida B:2 were constructed, over-expressed and purified as recombinant fusion proteins from Escherichia coli using affinity chromatography. Immunization of mice with rTbpA fragments resulted in a significant (p multocida B:2 resulted in a variable protective efficacy up to 50%. The study indicated the potential possibilities to incorporate full length TbpA in subunit vaccine formulation composed of synergistic subunit antigens against haemorrhagic septicaemia (HS) in cattle and buffalo.

  1. Process analysis of two-layered tube hydroforming with analytical and experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Seyedkashi, S. M. Hossein [The University of Birjand, Birjand (Iran, Islamic Republic of); Panahizadeh R, Valiollah [Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Xu, Haibin; Kim, Sang Yun; Moon, Young Hoon [Pusan National University, Busan (Korea, Republic of)


    Two-layered tubular joints are suitable for special applications. Designing and manufacturing of two layered components require enough knowledge about the tube material behavior during the hydroforming process. In this paper, hydroforming of two-layered tubes is investigated analytically, and the results are verified experimentally. The aim of this study is to derive an analytical model which can be used in the process design. Fundamental equations are written for both of the outer and inner tubes, and the total forming pressure is obtained from these equations. Hydroforming experiments are carried out on two different combinations of materials for inner and outer tubes; case 1: copper/aluminum and case 2: carbon steel/stainless steel. It is observed that experimental results are in good agreement with the theoretical model obtained for estimation of forming pressure able to avoid wrinkling.

  2. Lie symmetry analysis and exact solutions of the quasigeostrophic two-layer problem (United States)

    Bihlo, Alexander; Popovych, Roman O.


    The quasigeostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximal Lie invariance algebra is constructed. On the basis of these subalgebras, we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Wherever possible, reference to the physical meaning of the exact solutions is given. In particular, the well-known baroclinic Rossby wave solutions in the two-layer model are rediscovered.

  3. On stratification, barotropic tides, and secular changes in surface tidal elevations: Two-layer analytical models

    CERN Document Server

    Wetzel, Alfredo N; Cerovecki, Ivana; Hendershott, Myrl C; Karsten, Richard H; Miller, Peter D


    In this study the influence of stratification on surface tidal elevations in a two-layer analytical model is examined. The model assumes linearized, non-rotating, shallow-water dynamics in one dimension with astronomical forcing and allows for arbitrary topography. Both large scale (barotropic) and small scale (baroclinic) components of the surface tidal elevation are shown to be affected by stratification. It is also shown that the topography and basin boundaries affect the sensitivity of the barotropic surface tide to stratification significantly. In a companion paper it is shown that the barotropic tide in two-layer numerical models run in realistic global domains differs from its value in one-layer numerical models by amounts qualitatively consistent with analytic predictions from this paper. The analytical model also roughly predicts the sensitivity to perturbations in stratification in the two-layer domain model. Taken together, this paper and the companion paper therefore provide a framework to underst...

  4. Wave scattering by undulating bed topography in a two-layer ocean

    Institute of Scientific and Technical Information of China (English)



    The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.


    Institute of Scientific and Technical Information of China (English)

    ZHU Wei


    The Wave-making characteristics of a moving body in a two-layer fluid with free surface is investigated numerically and experimentally. The numerical analysis is based on the modified layered boundary integral equation system. The wave characteristics on the free surface and interface generated by a moving sphere and an ellipsoid is numerically simulated in both finite depth and infinite depth of lower layer model. The numerical results of the sphere are compared with the analytical results for a dipole with the same velocity in a two-layer fluid of finite depth. The dependence of the wave systems and structures on the characteristic quantities is discussed. Three kinds of measurement techniques are used in model experiments on the internal waves generated by a sphere advancing in a two-layer fluid. The effects of the varying velocity and stratification on the wavelength, wave amplitudes and the maximum half angles of internal waves are analyzed qualitatively.

  6. Band splitting and relative spin alignment in two-layer systems

    CERN Document Server

    Ovchinnikov, A A


    It is shown that the single-particle spectra of the low Hubbard zone in the two-layer correlated 2D-systems sharply differ in the case of different relative alignment of the layers spin systems. The behavior of the two-layer splitting in the Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub + subdelta gives all reasons for the hypothesis on the possible rearrangement of the F sub z -> AF sub z alignment configuration, occurring simultaneously with the superconducting transition. The effects of the spin alignment on the magnetic excitations spectrum, as the way for studying the spin structure of the two-layer systems, are discussed by the example of homogenous solutions for the effective spin models

  7. Ultrasound evaluation of the cesarean scar: comparison between one- and two layer uterotomy closure

    DEFF Research Database (Denmark)

    Glavind, Julie; Madsen, Lene Duch; Uldbjerg, Niels

    Objectives: To compare the residual myometrial thickness and the size of the cesarean scar defect after one- and two layer uterotomy closure. Methods: From July 2010 a continuous two-layer uterotomy closure technique replaced a continuous one-layer technique after cesarean delivery...... at the Department of Obstetrics and Gynecology at Aarhus University Hospital. A total of 149 consecutively invited women (68 women with one-layer and 81 women with two-layer closure) had their cesarean scar examined with 2D transvaginal sonography (TVS) 6-16 months post partum. Inclusion criteria were non......-pregnant women with one previous elective cesarean, no post-partum uterine infection or uterine re-operation, and no type 1 diabetes. Scar defect width, depth, and residual myometrial thickness were measured on the sagittal plane, and scar defect length was measured on the transverse plane. Results: The median...

  8. Design of two-layer switching rule for stabilization of switched linear systems with mismatched switching

    Institute of Scientific and Technical Information of China (English)

    Dan MA


    A two-layer switching architecture and a two-layer switching rule for stabilization of switched linear control systems are proposed, under which the mismatched switching between switched systems and their candidate hybrid controllers can be allowed. In the low layer, a state-dependent switching rule with a dwell time constraint to exponentially stabilize switched linear systems is given;in the high layer, supervisory conditions on the mismatched switching frequency and the mismatched switching ratio are presented, under which the closed-loop switched system is still exponentially stable in case of the candidate controller switches delay with respect to the subsystems. Different from the traditional switching rule, the two-layer switching architecture and switching rule have robustness, which in some extend permit mismatched switching between switched subsystems and their candidate controllers.

  9. Random Boundary Simulation of Pumping Groundwater on Two-layer Soft Soil Structure with Porous Media

    Institute of Scientific and Technical Information of China (English)


    Based on random theory,fluid dynamics,porous media and soil mechanics,the porosity and random characteristic of the two-layer soft soil in Wuhan region were studied in this paper.The random seepage coefficient on the two-layer soft soil was analyzed,and the seepage model and its random distribution function were given.The groundwater flow differential equations related to the two layer soft soil structure were also established.The evaluation procedure of effect boundary on the pumping water in deep foundation pit was put forward.Moreover,with an engineering example,the probability distribution on random boundary prediction for pumping water of foundation pit was computed.

  10. Interaction between TATA-Binding Protein (TBP and Multiprotein Bridging Factor-1 (MBF1 from the Filamentous Insect Pathogenic Fungus Beauveria bassiana.

    Directory of Open Access Journals (Sweden)

    Chi Song

    Full Text Available TATA-binding protein (TBP is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1 is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regulator of insect populations and can form intimate associations with certain plants. In order to gain a better understanding of the function of MBF1 in filamentous fungi, its interaction with TBP was demonstrated. The MBF1 and TBP homologs in B. bassiana were cloned and purified from a heterologous E. coli expression system. Whereas purified BbTBP was shown to be able to bind oligonucleotide sequences containing the TATA-motif (Kd ≈ 1.3 nM including sequences derived from the promoters of the B. bassiana chitinase and protease genes. In contrast, BbMBF1 was unable to bind to these same target sequences. However, the formation of a ternary complex between BbMBF1, BbTBP, and a TATA-containing target DNA sequence was seen in agarose gel electrophoretic mobility shift assays (EMSA. These data indicate that BbMBF1 forms direct interactions with BbTBP, and that the complex is capable of binding to DNA sequences containing TATA-motifs, confirming that BbTBP can link BbMBF1 to target sequences as part of the RNA transcriptional machinery in fungi.

  11. Interaction between TATA-Binding Protein (TBP) and Multiprotein Bridging Factor-1 (MBF1) from the Filamentous Insect Pathogenic Fungus Beauveria bassiana


    Chi Song; Almudena Ortiz-Urquiza; Sheng-Hua Ying; Jin-Xia Zhang; Nemat O Keyhani


    TATA-binding protein (TBP) is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1) is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regula...

  12. Lie symmetry analysis and exact solutions of the quasi-geostrophic two-layer problem

    CERN Document Server

    Bihlo, Alexander


    The quasi-geostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximum Lie invariance algebra is constructed. On the basis of these subalgebras we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Where possible, reference to the physical meaning of the exact solutions is given.

  13. Free surface simulation of a two-layer fluid by boundary element method

    Directory of Open Access Journals (Sweden)

    Weoncheol Koo


    Full Text Available A two-layer fluid with free surface is simulated in the time domain by a two-dimensional potential-based Numerical Wave Tank (NWT. The developed NWT is based on the boundary element method and a leap-frog time integration scheme. A whole domain scheme including interaction terms between two layers is applied to solve the boundary integral equation. The time histories of surface elevations on both fluid layers in the respective wave modes are verified with analytic results. The amplitude ratios of upper to lower elevation for various density ratios and water depths are also compared.

  14. The Generalized Energy Equation and Instability in the Two-layer Barotropic Vortex

    Institute of Scientific and Technical Information of China (English)


    The linear two-layer barotropic primitive equations in cylindrical coordinates are used to derive a generalized energy equation, which is subsequently applied to explain the instability of the spiral wave in the model. In the two-layer model, there are not only the generalized barotropic instability and the super highspeed instability, but also some other new instabilities, which fall into the range of the Kelvin-Helmholtz instability and the generalized baroclinic instability, when the upper and lower basic flows are different.They are perhaps the mechanisms of the generation of spiral cloud bands in tropical cyclones as well.

  15. Fabrication of a P-stabilized InP(0 0 1) surface at low pressure and temperature using t-butylphosphine (TBP) (United States)

    Fukuda, Yasuo; Kumano, Hiroshi; Nakamura, Hiroyuki


    Fabrication of a P-stabilized InP(0 0 1)-(2 × 1) surface at low pressure and temperature using t-butylphosphine (TBP) has been studied. The (2 × 1) surface was fabricated at 260 °C using TBP (5 × 10 -6 Torr) cracked with a hot W-filament although the (2 × 4) structure was not changed by exposing to TBP (5 × 10 -6-1 × 10 -5 Torr) at 260-280 °C without the filament. Mass spectra of the cracked TBP indicate that the relative spectral intensities of P and P 2 are increased by 1.3-1.5 times higher than TBP without the filament, leading to the result that the surface can be fabricated at low pressure and temperature. The formation rate of the (2 × 1) surface by our method is higher by about one order of magnitude even at lower pressure and temperature than the reported ALE method. The (2 × 1) surface is stable at 260-280 °C in an ultrahigh vacuum. This suggests that atomic layer epitaxy (ALE) of InP can be performed at low pressure and temperature using the hot W-filament. The Auger electron spectroscopy (AES) result indicates that carbon contamination does not occur on the surface by adsorption of TBP cracked by the filament.

  16. A two-layered approach to recognize high-level human activities

    NARCIS (Netherlands)

    N. Hu; G. Englebienne; B. Kröse


    Automated human activity recognition is an essential task for Human Robot Interaction (HRI). A successful activity recognition system enables an assistant robot to provide precise services. In this paper, we present a two-layered approach that can recognize sub-level activities and high-level activi

  17. Novel procedure to compute a contact zone magnitude of vibrations of two-layered uncoupled plates

    Directory of Open Access Journals (Sweden)

    Awrejcewicz J.


    Full Text Available A novel iteration procedure for dynamical problems, where in each time step, a contacting plates' zone is improved, is proposed. Therefore, a zone and magnitude of a contact load are also improved. Investigations of boundary conditions' influence on externally driven vibrations of uncoupled two-layer plates, where for each of the layers, the Kirchhoff hypothesis holds, are carried out.

  18. Learning behavior and temporary minima of two-layer neural networks

    NARCIS (Netherlands)

    Annema, Anne J.; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans


    This paper presents a mathematical analysis of the occurrence of temporary minima during training of a single-output, two-layer neural network, with learning according to the back-propagation algorithm. A new vector decomposition method is introduced, which simplifies the mathematical analysis of

  19. Bilateral telemanipulation With time delays: a two-layer approach combining passivity and transparency

    NARCIS (Netherlands)

    Franken, Michel; Stramigioli, Stefano; Misra, Sarthak; Secchi, Cristian; Macchelli, Alessandro


    In this paper, a two-layer approach is presented to guarantee the stable behavior of bilateral telemanipulation sys- tems in the presence of time-varying destabilizing factors such as hard contacts, relaxed user grasps, stiff control settings, and/or communication delays. The approach splits the con

  20. Coupling of Flexural and Longitudinal Damped Vibration in a Two-Layered Beam

    Directory of Open Access Journals (Sweden)

    F. Pourroy


    Full Text Available In dynamics, the effect of varying the constitutive materials’ thickness of a two-layered beam is investigated. Resonance frequencies and damping variations are determined. It is shown that for specific thicknesses the coupling of longitudinal and flexural vibrations influences the global modal damping ratio significantly.

  1. Two-layer sheet of gelatin: A new topical hemostatic agent. (United States)

    Takagi, Toshitaka; Tsujimoto, Hiroyuki; Torii, Hiroko; Ozamoto, Yuki; Hagiwara, Akeo


    Uncontrolled surgical bleeding is associated with increased morbidity, mortality, and hospital cost. Topical hemostatic agents available today have problems controlling hemostatic effects; furthermore, their handling is difficult and they are unsafe. We devised a new hemostatic agent comprising gelatin sponge and film designed to be applied to the bleeding site, thereby creating a topical hemostatic agent made of gelatin alone. The gelatin was prepared by alkali treatment to eliminate viral activity. Hemostatic effects, surgical handling, and tissue reactions of the materials, namely a two-layer sheet of gelatin, TachoSil, and gelatin sponge, were evaluated using 21 dogs' spleens. The two-layer gelatin sheet and gelatin sponge exhibited superior hemostatic effects (100% hemostasis completed) compared with TachoSil (0-17% hemostasis). The gelatin matrix immediately absorbed blood flowing from wounds and activated the autologous components in the absorbed blood that promoted coagulation at the bleeding site. The two-layer gelatin sheet had the best surgical handling among the evaluated materials. Materials made of gelatin were associated with fewer inflammatory reactions compared with materials of TachoSil. The two-layer sheet of gelatin is a useful topical agent because of its superior hemostatic effects and usability, and is associated with a lower risk of transmitting diseases and inflammatory reactions. Copyright © 2016. Published by Elsevier Taiwan.

  2. Single-layer versus two-layer stamps for reduced pressure thermal nanoimprint (United States)

    Papenheim, Marc; Dhima, Khalid; Wang, Si; Steinberg, Christian; Scheer, Hella-Christin


    Low-pressure imprint is interesting to avoid stamp deformation, stamp failure as well as polymer recovery. When large-area stamps are prepared with a stepping procedure, low pressure is required to optimize the stitching. However, with low-pressure imprint, conformal contact between stamp and substrate is critical. Admittedly, the imprint pressure required for conformal contact depends on the stamp material and its thickness. To get an idea to which extent the imprint pressure can be reduced with a flexible stamp, we compared different stamp materials and stamp architectures, single-layer stamps and two-layer stamps. The two-layer stamps are replica stamps, where the structures were replicated in a thin layer of OrmoStamp, fixed by a backplane. On the background of plate theory, we deduce the pressure reduction compared to a Si stamp by calculating the respective pressure ratio, independent from geometries. In addition, temperature-induced issues are addressed which are of relevance for a thermal imprint process. These issues are related to the mismatch between the thermal expansion coefficients of the stamp and the substrate, and in case of a two-layer stamp, to the mismatch between the backplane material and the top layer. The latter results in temperature-induced stamp bending. On the basis of simple analytical calculations, the potential of single-layer stamps and two-layer stamps with respect to thermal imprint at reduced pressure is discussed and guidelines are provided to assess the imprint situation when replica stamps are used for imprint. The results demonstrate the attractiveness of two-layer stamps for reduced pressure nanoimprint, even in a temperature-based process.

  3. Waves induced by a submerged moving dipole in a two-layer fluid of finite depth

    Institute of Scientific and Technical Information of China (English)

    Gang Wei; Dongqiang Lu; Shiqiang Dai


    The waves induced by a moving dipole in a twofluid system are analytically and experimentally investigated.The velocity potential of a dipole moving horizontally in the lower layer of a two-layer fluid with finite depth is derived by superposing Green's functions of sources (or sinks). The far-field waves are studied by using the method of stationary phase. The effects of two resulting modes, i.e. the surfaceand internal-wave modes, on both the surface divergence field and the interfacial elevation are analyzed. A laboratory study on the internal waves generated by a moving sphere in a two-layer fluid is conducted in a towing tank under the same conditions as in the theoretical approach. The qualitative consistency between the present theory and the laboratory study is examined and confirmed.

  4. Analysis of Two-Layered Random Interfaces for Two Dimensional Widom-Rowlinson's Model

    Directory of Open Access Journals (Sweden)

    Jun Wang


    Full Text Available The statistical behaviors of two-layered random-phase interfaces in two-dimensional Widom-Rowlinson's model are investigated. The phase interfaces separate two coexisting phases of the lattice Widom-Rowlinson model; when the chemical potential μ of the model is large enough, the convergence of the probability distributions which describe the fluctuations of the phase interfaces is studied. In this paper, the backbones of interfaces are introduced in the model, and the corresponding polymer chains and cluster expansions are developed and analyzed for the polymer weights. And the existence of the free energy for two-layered random-phase interfaces of the two-dimensional Widom-Rowlinson model is given.

  5. Nonlinear dynamics at the interface of two-layer stratified flows over pronounced obstacles

    CERN Document Server

    Cabeza, C; Bove, I; Freire, D; Marti, Arturo C; Sarasua, L G; Usera, G; Montagne, R; Araújo, M


    The flow of a two--layer stratified fluid over an abrupt topographic obstacle, simulating relevant situations in oceanographic problems, is investigated numerically and experimentally in a simplified two--dimensional situation. Experimental results and numerical simulations are presented at low Froude numbers in a two-layer stratified flow and for two abrupt obstacles, semi--cylindrical and prismatic. We find four different regimes of the flow immediately past the obstacles: sub-critical (I), internal hydraulic jump (II), Kelvin-Helmholtz at the interface (III) and shedding of billows (IV). The critical condition for delimiting the experiments is obtained using the hydraulic theory. Moreover, the dependence of the critical Froude number on the geometry of the obstacle are investigated. The transition from regime III to regime IV is explained with a theoretical stability analysis. The results from the stability analysis are confirmed with the DPIV measurements. In regime (IV), when the velocity upstream is lar...

  6. Nonstationary Axisymmetric Temperature Field in a Two-Layer Slab Under Mixed Heating Conditions (United States)

    Turchin, I. N.; Timar, I.; Kolodii, Yu. A.


    With the use of the Laguerre and Hankel integral transforms, the solution of a two-dimensional initial-boundary-value heat conduction problem for a two-layer slab under mixed boundary conditions is constructed: one of the surfaces is heated by a heat flux distributed axisymmetrically in a circle of radius R and is cooled by the Newton law outside this circle. The solution of the problem is reduced to a sequence of infinite quasi-regular systems of algebraic equations. The results of numerical analysis of the temperature field in the two-layer slab made from an aluminum alloy and ceramicsare presented depending on the relative geometric properties of the components and cooling intensity.

  7. A Two-layer Model for the Simulation of the VARTM Process with Resin Distribution Layer (United States)

    Young, Wen-Bin


    Vacuum assisted resin transfer molding (VARTM) is one of the important processes to fabricate high performance composites. In this process, resin is drawn into the mold to impregnate the fiber reinforcement to a form composite. A resin distribution layer with high permeability was often introduced on top of the fiber reinforcement to accelerate the filling speed. Due to the difference of the flow resistance in the resin distribution layer and the reinforcement as well as the resulting through thickness transverse flow, the filling flow field is intrinsically three-dimensional. This study developed a two-layer model with two-dimensional formulation to simulate the filling flow of the VARTM process with a resin distribution layer. Two-dimensional flow was considered in each layer and a transverse flow in the thickness direction was estimated between the two layers. Thermal analysis including the transverse convection was also performed to better simulate the temperature distribution.

  8. Estimation of apparent soil resistivity for two-layer soil structure

    Energy Technology Data Exchange (ETDEWEB)

    Nassereddine, M.; Rizk, J.; Nagrial, M.; Hellany, A. [School of Computing, Engineering and Mathematics, University of Western Sydney (Australia)


    High voltage (HV) earthing design is one of the key elements when it comes to safety compliance of a system. High voltage infrastructure exposes workers and people to unsafe conditions. The soil structure plays a vital role in determining the allowable and actual step/touch voltage. This paper presents vital information when working with two-layer soil structure. It shows the process as to when it is acceptable to use a single layer instead of a two-layer structure. It also discusses the simplification of the soil structure approach depending on the reflection coefficient. It introduces the reflection coefficient K interval which determines if single layer approach is acceptable. Multiple case studies are presented to address the new approach and its accuracy.


    Institute of Scientific and Technical Information of China (English)

    Xu Zhaoting; Xu Hao; Samuel Shan-pu Shen


    A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations(AKdV),which are derived by the authors in terms of Whitham's method of averaging[1,2].From the AKdV equations,group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains,furthermore an analytical solution of the tailing wavetrain generation is found theoretically.A comparison between the theoretical and numerical results is carried out in the present paper,which shows that the theoretical results are in good agreement with the numerical ones,obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.

  10. Asymptotic Modelling of Crystallisation in Two Layers Systems. Application to Methane Hydrate Formation in Batch Reactor.


    Cournil, Michel; Herri, Jean-Michel


    6 pages; This paper proposes to re-visit the problem of gas-liquid crystallization in the framework of a two-layer model and with the help of data coming from experiments on methane hydrate crystallization in a semi-batch reactor. Preliminary quantitative discussion of the order of magnitude of different effects makes possible realistic simplifications in the theoretical models. In particular, the role of the interfacial film is clearly defined. As previous authors did, we use a formulation i...

  11. Unidirectional light propagation through two-layer nanostructures based on optical near-field interactions

    CERN Document Server

    Naruse, Makoto; Ishii, Satoshi; Drezet, Aurélien; Huant, Serge; Hoga, Morihisa; Ohyagi, Yasuyuki; Matsumoto, Tsutomu; Tate, Naoya; Ohtsu, Motoichi


    We theoretically demonstrate direction-dependent polarization conversion efficiency, yielding unidirectional light transmission, through a two-layer nanostructure by using the angular spectrum representation of optical near-fields. The theory provides results that are consistent with electromagnetic numerical simulations. This study reveals that optical near-field interactions among nanostructured matter can provide unique optical properties, such as the unidirectionality observed here, and offers fundamental guiding principles for understanding and engineering nanostructures for realizing novel functionalities.

  12. Two-layer cold storage method for pancreas and islet cell transplantation

    Institute of Scientific and Technical Information of China (English)

    Yasuhiro; Fujino


    The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging ...

  13. SH-TM mathematical analogy for the two-layer case. A magnetotellurics application


    J. Carcione; F. Poletto


    The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission) problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised) and TM (transverse-magnetic) waves. In particular, w...

  14. On Theory of Dispersive Transport in a Two-Layer Polymer Structure (United States)

    Sibatov, R. T.; Morozova, E. V.


    Dispersive transport of charge carriers in a two-layer polymer structure is modeled on the basis of the integrodifferential equation of hereditary diffusion. The model of multiple trapping in a bilayer is generalized to the case of an arbitrary density of localized states. With the help of an efficient Monte Carlo algorithm, curves of the transient current are calculated and their features are explained within the framework of a stochastic interpretation of the process.

  15. On two-layer models and the similarity functions for the PBL (United States)

    Brown, R. A.


    An operational Planetary Boundary Layer model which employs similarity principles and two-layer patching to provide state-of-the-art parameterization for the PBL flow is used to study the popularly used similarity functions, A and B. The expected trends with stratification are shown. The effects of baroclinicity, secondary flow, humidity, latitude, surface roughness variation and choice of characteristic height scale are discussed.

  16. Two-layer cold storage method for pancreas and islet cell transplantation


    Fujino, Yasuhiro


    The two-layer cold storage method (TLM) was first reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins’ solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storag...

  17. A Two Layer Approach to the Computability and Complexity of Real Functions

    DEFF Research Database (Denmark)

    Lambov, Branimir Zdravkov


    We present a new model for computability and complexity of real functions together with an implementation that it based on it. The model uses a two-layer approach in which low-type basic objects perform the computation of a real function, but, whenever needed, can be complemented with higher type...... in computable analysis, while the efficiency of the implementation is not compromised by the need to create and maintain higher-type objects....

  18. Mutation analysis of the TATA box-binding protein (TBP) gene in Chinese Han patients with spinocerebellar ataxia. (United States)

    Xu, Q; Li, X H; Wang, J L; Jiang, H; Zhang, S; Lei, L F; Shen, L; Xia, K; Pan, Q; Long, Z G; Tang, B S


    Spinocerebellar ataxia type 17 (SCA17) is a rare autosomal dominant progressive neurodegenerative disease caused by the CAG/CAA expansion in the TATA box-binding protein (TBP) gene. This study aimed to assess the frequency of SCA17 in patients from mainland China. Analysis of CAG/CAA expansion in this gene was performed in 263 patients consisting of 100 probands with dominantly inherited ataxias and 163 patients with sporadic ataxias. Abnormal expansion of CAG/CAA repeats in the SCA17 locus was found in a proband and her younger sister. To our knowledge, we are providing the first kindred analysis of SCA17 in mainland China.

  19. Huntington's disease-like and ataxia syndromes: identification of a family with a de novo SCA17/TBP mutation

    DEFF Research Database (Denmark)

    Bech, Sara; Petersen, Thor; Nørremølle, Anne;


    The autosomal dominant spinocerebellar ataxias, commonly referred to as SCAs, are clinically and genetically heterogeneous neurodegenerative disorders. Twenty-eight genetic subtypes have been identified, of which 7 are caused by expansion of a CAG trinucleotide repeat that encodes a polyglutamine...... with a Huntington's disease-like phenotype without the HD-gene mutation and 178 patients with genetically unclassified cerebellar ataxia for the mutation in TBP. A 33-year old woman presenting with an HD like phenotype with a de novo 54 CAG/CAA repeat expansion was identified. Her normal allele included 38 repeats......-like phenotypes and ataxia syndromes, also in isolated cases....

  20. Phase transitions and kinetic properties of gold nanoparticles confined between two-layer graphene nanosheets (United States)

    Wang, Gang; Wu, Nanhua; Chen, Jionghua; Wang, Jinjian; Shao, Jingling; Zhu, Xiaolei; Lu, Xiaohua; Guo, Lucun


    The thermodynamic and kinetic behaviors of gold nanoparticles confined between two-layer graphene nanosheets (two-layer-GNSs) are examined and investigated during heating and cooling processes via molecular dynamics (MD) simulation technique. An EAM potential is applied to represent the gold-gold interactions while a Lennard-Jones (L-J) potential is used to describe the gold-GNS interactions. The MD melting temperature of 1345 K for bulk gold is close to the experimental value (1337 K), confirming that the EAM potential used to describe gold-gold interactions is reliable. On the other hand, the melting temperatures of gold clusters supported on graphite bilayer are corrected to the corresponding experimental values by adjusting the εAu-C value. Therefore, the subsequent results from current work are reliable. The gold nanoparticles confined within two-layer GNSs exhibit face center cubic structures, which is similar to those of free gold clusters and bulk gold. The melting points, heats of fusion, and heat capacities of the confined gold nanoparticles are predicted based on the plots of total energies against temperature. The density distribution perpendicular to GNS suggests that the freezing of confined gold nanoparticles starts from outermost layers. The confined gold clusters exhibit layering phenomenon even in liquid state. The transition of order-disorder in each layer is an essential characteristic in structure for the freezing phase transition of the confined gold clusters. Additionally, some vital kinetic data are obtained in terms of classical nucleation theory.

  1. Long-term persistence of oil from the Exxon Valdez spill in two-layer beaches (United States)

    Li, Hailong; Boufadel, Michel C.


    Oil spilled from the tanker Exxon Valdez in 1989 (refs 1, 2) persists in the subsurface of gravel beaches in Prince William Sound, Alaska. The contamination includes considerable amounts of chemicals that are harmful to the local fauna. However, remediation of the beaches was stopped in 1992, because it was assumed that the disappearance rate of oil was large enough to ensure a complete removal of oil within a few years. Here we present field data and numerical simulations of a two-layered beach with a small freshwater recharge in the contaminated area, where a high-permeability upper layer is underlain by a low-permeability lower layer. We find that the upper layer temporarily stored the oil, while it slowly and continuously filled the lower layer wherever the water table dropped below the interface of the two layers, as a result of low freshwater recharge from the land. Once the oil entered the lower layer, it became entrapped by capillary forces and persisted there in nearly anoxic conditions that are a result of the tidal hydraulics in the two-layered beaches. We suggest that similar dynamics could operate on tidal gravel beaches around the world, which are particularly common in mid- and high-latitude regions, with implications for locating spilled oil and for its biological remediation.

  2. Steady internal waves in an exponentially stratified two-layer fluid (United States)

    Makarenko, Nikolay; Maltseva, Janna; Ivanova, Kseniya


    The problem on internal waves in a weakly stratified two-layered fluid is studied analytically. We suppose that the fluid possess exponential stratification in both the layers, and the fluid density has discontinuity jump at the interface. By that, we take into account the influence of weak continuous stratification outside of sharp pycnocline. The model equation of strongly nonlinear interfacial waves propagating along the pycnocline is considered. This equation extends approximate models [1-3] suggested for a two-layer fluid with one homogeneous layer. The derivation method uses asymptotic analysis of fully nonlinear Euler equations. The perturbation scheme involves the long wave procedure with a pair of the Boussinesq parameters. First of these parameters characterizes small density slope outside of pycnocline and the second one defines small density jump at the interface. Parametric range of solitary wave solutions is characterized, including extreme regimes such as plateau-shape solitary waves. This work was supported by RFBR (grant No 15-01-03942). References [1] N. Makarenko, J. Maltseva. Asymptotic models of internal stationary waves, J. Appl. Mech. Techn. Phys, 2008, 49(4), 646-654. [2] N. Makarenko, J. Maltseva. Phase velocity spectrum of internal waves in a weakly-stratified two-layer fluid, Fluid Dynamics, 2009, 44(2), 278-294. [3] N. Makarenko, J. Maltseva. An analytical model of large amplitude internal solitary waves, Extreme Ocean Waves, 2nd ed. Springer 2015, E.Pelinovsky and C.Kharif (Eds), 191-201.

  3. A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves (United States)

    Lee, V.; Payne, A. J.; Gregory, J. M.


    We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer. The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.

  4. A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves

    Directory of Open Access Journals (Sweden)

    V. Lee


    Full Text Available We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer.

    The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.

  5. A two-layer optimization model for high-speed railway line planning

    Institute of Scientific and Technical Information of China (English)

    Li WANG; Li-min JIA; Yong QIN; Jie XU; Wen-ring MO


    Line planning is the first important strategic element in the railway operation planning process,which will directly affect the successive planning to determine the efficiency of the whole railway system.A two-layer optimization model is proposed within a simulation framework to deal with the high-speed railway (HSR) line planning problem.In the model,the top layer aims at achieving an optimal stop-schedule set with the service frequencies,and is formulated as a nonlinear program,solved by genetic algorithm.The objective of top layer is to minimize the total operation cost and unserved passenger volume.Given a specific stop-schedule,the bottom layer focuses on weighted passenger flow assignment,formulated as a mixed integer program with the objective of maximizing the served passenger volume and minimizing the total travel time for all passengers.The case study on Taiwan HSR shows that the proposed two-layer model is better than the existing techniques.In addition,this model is also illustrated with the Beijing-Shanghai HSR in China.The result shows that the two-layer optimization model can reduce computation complexity and that an optimal set of stop-schedules can always be generated with less calculation time.

  6. Diffraction of Water Waves by A Vertically Floating Cylinder in A Two-Layer Fluid

    Institute of Scientific and Technical Information of China (English)


    In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer luid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder are obtained by use of the method of eigenfunction expansions. The hydrodynamic loads on the vertically floating cylinder in a two-layer fluid include not only the surge, heave and pitch exciting forces due to the incident wave of the surface-wave mode, but also those due to the incident wave of the internal-wave mode. This is different from the case of a homogenous fluid. Some given examples show that, for a two-layer fluid system with a small density difference, the hydrodynamic loads for the surface-wave mode do not differ significantly from those due to surface waves in a single-layer fluid, but the hydrodynamic loads for the internal-wave mode are important over a wide range of frequencies. Moreover, also considered are the free surface and interface elevations generated by the diffraction wave due to the incident wave of the surface-wave and internal-wave modes, and transfer of energy between modes.

  7. Photochemical Oxidation of a Manganese(III) Complex with Oxygen and Toluene Derivatives to Form a Manganese(V)-Oxo Complex (United States)

    Jung, Jieun; Ohkubo, Kei; Prokop-Prigge, Katharine A.; Neu, Heather M.; Goldberg, David P.; Fukuzumi, Shunichi


    Visible light photoirradiation of an oxygen-saturated benzonitrile solution of a manganese(III) corrolazine complex [(TBP8Cz)MnIII (1): [TBP8Cz = octakis(p-tert-butylphenyl)corrolazinato3−] in the presence of toluene derivatives resulted in formation of the manganese(V)-oxo complex [(TBP8Cz)MnV(O)]. The photochemical oxidation of (TBP8Cz)MnIII with O2 and hexamethylbenzene (HMB) led to the isosbestic conversion of 1 to (TBP8Cz)MnV(O), accompanied by the selective oxidation of HMB to pentamethylbenzyl alcohol (87%). The formation rate of (TBP8Cz)MnV(O) increased with methyl group substitution, from toluene, p-xylene, mesitylene, durene, pentamethylbenzene, up to hexamethylbenzene. Deuterium kinetic isotope effects (KIEs) were observed for toluene (KIE = 5.4) and mesitylene (KIE = 5.3). Femtosecond laser flash photolysis of (TBP8Cz)MnIII revealed the formation of a tripquintet excited state, which was rapidly converted to a tripseptet excited state. The tripseptet excited state was shown to be the key, activated state that reacts with O2 via a diffusion-limited rate constant. The data allow for a mechanism to be proposed in which the tripseptet excited state reacts with O2 to give the putative (TBP8Cz)MnIV(O2•−), which then abstracts a hydrogen atom from the toluene derivatives in the rate-determining step. The mechanism of hydrogen abstraction is discussed by comparison of the reactivity with the hydrogen abstraction from the same toluene derivatives by cumylperoxyl radical. Taken together, the data suggest a new catalytic method is accessible for the selective oxidation of C-H bonds with O2 and light, and the first evidence for catalytic oxidation of C–H bonds was obtained with 10-methyl-9,10-dihydroacridine as a substrate. PMID:24219426

  8. TBP-like Protein (TLP) Disrupts the p53-MDM2 Interaction and Induces Long-lasting p53 Activation. (United States)

    Maeda, Ryo; Tamashiro, Hiroyuki; Takano, Kazunori; Takahashi, Hiro; Suzuki, Hidefumi; Saito, Shinta; Kojima, Waka; Adachi, Noritaka; Ura, Kiyoe; Endo, Takeshi; Tamura, Taka-Aki


    Stress-induced activation of p53 is an essential cellular response to prevent aberrant cell proliferation and cancer development. The ubiquitin ligase MDM2 promotes p53 degradation and limits the duration of p53 activation. It remains unclear, however, how p53 persistently escapes MDM2-mediated negative control for making appropriate cell fate decisions. Here we report that TBP-like protein (TLP), a member of the TBP family, is a new regulatory factor for the p53-MDM2 interplay and thus for p53 activation. We found that TLP acts to stabilize p53 protein to ensure long-lasting p53 activation, leading to potentiation of p53-induced apoptosis and senescence after genotoxic stress. Mechanistically, TLP interferes with MDM2 binding and ubiquitination of p53. Moreover, single cell imaging analysis shows that TLP depletion accelerates MDM2-mediated nuclear export of p53. We further show that a cervical cancer-derived TLP mutant has less p53 binding ability and lacks a proliferation-repressive function. Our findings uncover a role of TLP as a competitive MDM2 blocker, proposing a novel mechanism by which p53 escapes the p53-MDM2 negative feedback loop to modulate cell fate decisions.


    Directory of Open Access Journals (Sweden)

    K. S. Kurochka


    Full Text Available Subject of Research. Computation of composite material designs requires application of numerical methods. The finiteelement method usage is connected with surface approximation problems. Application of volumetric and laminar elements leads to systems with large sizes and a great amount of computation. The objective of this paper is to present an equivalent two-layer mathematical model for evaluation of displacements and stresses of cross-ply laminated cone shells subjected to uniformly distributed load. An axially symmetric element for shell problems is described. Method. Axially symmetric finite element is proposed to be applied in calculations with use of correlation for the inner work of each layer separately. It gives the possibility to take into account geometric and physical nonlinearities and non-uniformity in the layers of the shell. Discrete mathematical model is created on the base of the finite-element method with the use of possible motions principle and Kirchhoff–Love assumptions. Hermite element is chosen as a finite one. Cone shell deflection is considered as the quantity sought for. Main Results. One-layered and two-layered cone shells have been considered for proposed mathematical model verification with known analytical and numerical analytical solutions, respectively. The axial displacements of the two-layered cone are measured with an error not exceeding 5.4 % for the number of finite elements equal to 30. The proposed mathematical model requires fewer nodes to define the finite element meshing of the system and much less computation time. Thereby time for finding solution decreases considerably. Practical Relevance. Proposed model is applicable for computation of multilayered designs under axially symmetric loads: composite high-pressure bottles, cylinder shaped fiberglass pipes, reservoirs for explosives and flammable materials, oil and gas storage tanks.


    Directory of Open Access Journals (Sweden)

    A. R. Baev


    Full Text Available Peculiarities of the plate wave propagation through two-layered thin plate have been analyzed and formulas for velocity determination of the quickest plate mode have been proposed.  The ascertained interaction makes it possible   to determine coating layer thickness in accordance with the given and known elastic parameters of contacting materials. On the basis of the developed methodology experiments have been carried out that revealed qualitative and quantitative correspondence  between theoretical and experimental data. The paper shows a principle possibility for assessment  of  material separation surface by time propagation data of the investigated mode .

  11. Determination of homeostatic elastic moduli in two layers of the esophagus

    DEFF Research Database (Denmark)

    Gregersen, Hans; Liao, Donghua; Fung, Yuan Cheng


    for determination of incremental moduli in circumferential, axial, and cross directions in the two layers. The experiments are inflation, axial stretching, circumferential bending, and axial bending. The analysis takes advantage of knowing the esophageal zero-stress state (an open sector with an opening angle of 59......The function of the esophagus is mechanical. To understand the function, it is necessary to know how the stress and strain in the esophagus can be computed, and how to determine the stress-strain relationship of the wall materials. The present article is devoted to the issue of determining...

  12. A novel two-layer compact electromagnetic bandgap (EBG) structure and its applications in microwave circuits

    Institute of Scientific and Technical Information of China (English)

    YANG; Ning(杨宁); CHEN; Zhining; (陈志宁); WANG; Yunyi; (王蕴仪); Chia; M.; Y.; W.


    This paper presents a novel two-layer electromagnetic bandgap (EBG) structure. The studies on the characteristics of the cell are carried out numerically and experimentally. A lumped-LC equivalent circuit extracted from the numerical simulation is used to model the bandgap characteristics of the proposed EBG structure. The influences of geometric parameters on the operation frequency and equivalent LC parameters are discussed. A meander line high performance bandstop filter and a notch type duplexer are designed and measured. These EBG structures are shown to have potential applications in microwave and RF systems.

  13. A Two-Layered Model for Dynamic Supply Chain Management Considering Transportation Constraint (United States)

    Tanimizu, Yoshitaka; Harada, Kana; Ozawa, Chisato; Iwamura, Koji; Sugimura, Nobuhiro

    This research proposes a two-layered model for dynamic supply chain management considering transportation constraint. The model provides a method for suppliers to estimate suitable prices and delivery times of products based on not only production schedules but also transportation plans in consideration of constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the model. The prototype system is available to determine suitable shipping times and loading capacities of transportation vehicles.

  14. Flows induced by sorption on fibrous material in a two-layer oil-water system (United States)

    Chaplina, T. O.; Chashechkin, Yu. D.; Stepanova, E. V.


    The processes of sorption on fibrous materials in the open elliptic cell filled with a two-layer oil-water liquid at rest are investigated experimentally. When the sorption efficiency dependent on the type of material proves to be reasonably high, large-scale flows are formed in the liquid. In this case, the uniformity of distribution of oil is violated and the free surface of the water is partially restored. The trajectories of motion of individual oil droplets on a released water surface are tracked, and the transfer rates are calculated in various phases of the process.

  15. SH-TM mathematical analogy for the two-layer case. A magnetotellurics application

    Directory of Open Access Journals (Sweden)

    J. Carcione


    Full Text Available The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised and TM (transverse-magnetic waves. In particular, we illustrate examples related to the magnetotelluric method applied to geothermal systems and consider the effects of anisotropy. The solution is tested with the classical solution for stratified isotropic media.

  16. Solitary SH waves in two-layered traction-free plates (United States)

    Djeran-Maigre, Irini; Kuznetsov, Sergey


    A solitary wave, resembling a soliton wave, is observed when analyzing the linear problem of polarized shear (SH) surface acoustic waves propagating in elastic orthotropic two-layered traction-free plates. The analysis is performed by applying a special complex formalism and the Modified Transfer Matrix (MTM) method. Conditions for the existence of solitary SH waves are obtained. Analytical expressions for the phase speed of the solitary wave are derived. To cite this article: I. Djeran-Maigre, S. Kuznetsov, C. R. Mecanique 336 (2008).

  17. Theories of multiple equilibria and weather regimes : A critical reexamination. II - Baroclinic two-layer models (United States)

    Cehelsky, Priscilla; Tung, Ka Kit


    Previous results based on low- and intermediate-order truncations of the two-layer model suggest the existence of multiple equilibria and/or multiple weather regimes for the extratropical large-scale flow. The importance of the transient waves in the synoptic scales in organizing the large-scale flow and in the maintenance of weather regimes was emphasized. The result shows that multiple equilibria/weather regimes that are present in lower-order models examined disappear when a sufficient number of modes are kept in the spectral expansion of the solution to the governing partial differential equations. Much of the chaotic behavior of the large-scale flow that is present in intermediate-order models is now found to be spurious. Physical reasons for the drastic modification are offered. A peculiarity in the formulation of most existing two-layer models is noted that also tends to exaggerate the importance of baroclinic processes and increase the degree of unpredictability of the large-scale flow.

  18. Photoacoustic investigation of the effective diffusivity of two-layer semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Medina, J; Gurevich, Yu. G; Logvinov G, N; Rodriguez, P; Gonzalez de la Cruz, G. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)


    In this work, the problem of the effective thermal diffusivity of two-layer systems is investigated using the photoacoustic spectroscopy. The experimental results are examined in terms of the effective thermal parameters of the composite system determined from an homogeneous material which produces the same physical response under an external perturbation in the detector device. It is shown, that the effective thermal conductivity is not symmetric under exchange of the two layers of the composite; i.e., the effective thermal parameters depend upon which layer is illuminated in the photoacoustic experiments. Particular emphasis is given to the characterization of the interface thermal conductivity between the layer-system. [Spanish] En el presente trabajo se utiliza la espectroscopia fotoacustica para medir la difusividad termica de un sistema de dos capas. Los resultados experimentales son analizados en terminos de los parametros termicos efectivos determinados a partir de un material homogeneo, el cual produce la misma respuesta fisica bajo una perturbacion externa. Se puso particular enfasis en la caracterizacion de los efectos de interfase en el flujo de calor en el sistema de dos capas. Los resultados experimentales se comparan con el modelo teorico propuesto en este trabajo.

  19. Modelling of fast jet formation under explosion collision of two-layer alumina/copper tubes

    Directory of Open Access Journals (Sweden)

    I Balagansky


    Full Text Available Under explosion collapse of two-layer tubes with an outer layer of high-modulus ceramics and an inner layer of copper, formation of a fast and dense copper jet is plausible. We have performed a numerical simulation of the explosion collapse of a two-layer alumina/copper tube using ANSYS AUTODYN software. The simulation was performed in a 2D-axis symmetry posting on an Eulerian mesh of 3900x1200 cells. The simulation results indicate two separate stages of the tube collapse process: the nonstationary and the stationary stage. At the initial stage, a non-stationary fragmented jet is moving with the velocity of leading elements up to 30 km/s. The collapse velocity of the tube to the symmetry axis is about 2 km/s, and the pressure in the contact zone exceeds 700 GPa. During the stationary stage, a dense jet is forming with the velocity of 20 km/s. Temperature of the dense jet is about 2000 K, jet failure occurs when the value of effective plastic deformation reaches 30.

  20. Validation of the Two-Layer Model for Correcting Clear Sky Reflectance Near Clouds (United States)

    Wen, Guoyong; Marshak, Alexander; Evans, K. Frank; Vamal, Tamas


    A two-layer model was developed in our earlier studies to estimate the clear sky reflectance enhancement near clouds. This simple model accounts for the radiative interaction between boundary layer clouds and molecular layer above, the major contribution to the reflectance enhancement near clouds for short wavelengths. We use LES/SHDOM simulated 3D radiation fields to valid the two-layer model for reflectance enhancement at 0.47 micrometer. We find: (a) The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; and (b) The magnitude of the 2-layer modeled enhancement agree reasonably well with the "truth" with some expected underestimation. We further extend our model to include cloud-surface interaction using the Poisson model for broken clouds. We found that including cloud-surface interaction improves the correction, though it can introduced some over corrections for large cloud albedo, large cloud optical depth, large cloud fraction, large cloud aspect ratio. This over correction can be reduced by excluding scenes (10 km x 10km) with large cloud fraction for which the Poisson model is not designed for. Further research is underway to account for the contribution of cloud-aerosol radiative interaction to the enhancement.

  1. Risks of an epidemic in a two-layered railway-local area traveling network (United States)

    Ruan, Zhongyuan; Hui, Pakming; Lin, Haiqing; Liu, Zonghua


    In view of the huge investments into the construction of high speed rails systems in USA, Japan, and China, we present a two-layer traveling network model to study the risks that the railway network poses in case of an epidemic outbreak. The model consists of two layers with one layer representing the railway network and the other representing the local-area transportation subnetworks. To reveal the underlying mechanism, we also study a simplified model that focuses on how a major railway affects an epidemic. We assume that the individuals, when they travel, take on the shortest path to the destination and become non-travelers upon arrival. When an infection process co-evolves with the traveling dynamics, the railway serves to gather a crowd, transmit the disease, and spread infected agents to local area subnetworks. The railway leads to a faster initial increase in infected agents and a higher steady state infection, and thus poses risks; and frequent traveling leads to a more severe infection. These features revealed in simulations are in agreement with analytic results of a simplified version of the model.

  2. Traffic dynamics on two-layer complex networks with limited delivering capacity (United States)

    Ma, Jinlong; Han, Weizhan; Guo, Qing; Wang, Zhenyong


    The traffic dynamics of multi-layer networks has attracted a great deal of interest since many real networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the average delivery capacity allocation strategy is susceptible to congestion with the wildly used shortest path routing protocol on two-layer complex networks. In this paper, we introduce a delivery capacity allocation strategy into the traffic dynamics on two-layer complex networks and focus on its effect on the traffic capacity measured by the critical point Rc of phase transition from free flow to congestion. When the total nodes delivering capacity is fixed, the delivering capacity of each node in physical layer is assigned to the degree distributions of both the physical and logical layers. Simulation results show that the proposed strategy can bring much better traffic capacity than that with the average delivery capacity allocation strategy. Because of the significantly improved traffic performance, this work may be useful for optimal design of networked traffic dynamics.

  3. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    Directory of Open Access Journals (Sweden)

    E. Ramdan


    Full Text Available Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode. The aim of this study is to measure and calculate the earth resistance of a combined grid-multiple rods electrode buried in a two-layer soil and to confirm the simplicity and accuracy of the used formula. Approach: Soil resistivity was measured using Wenner four point method. Advanced earth resistivity measurement interpretation techniques which include graphical curve matching based on master curves and an advanced computer program based on a genetic algorithm are used in this study. Results: Based on the resistivity data, the earth resistance value was calculated using the formulas obtained from the literature. Measurements of the earth resistance of the earthing system were also conducted using the fall of potential method. Conclusion/Recommendations: A very good agreement was obtained between the measured and calculated earth resistance values. This research is the first time ever conducted where the measured earth resistance values are compared directly with the calculated earth values.

  4. Numerical simulation and analysis of complex patterns in a two-layer coupled reaction diffusion system

    Institute of Scientific and Technical Information of China (English)

    李新政; 白占国; 李燕; 贺亚峰; 赵昆


    The resonance interaction between two modes is investigated using a two-layer coupled Brusselator model. When two different wavelength modes satisfy resonance conditions, new modes will appear, and a variety of superlattice patterns can be obtained in a short wavelength mode subsystem. We find that even though the wavenumbers of two Turing modes are fixed, the parameter changes have infl uences on wave intensity and pattern selection. When a hexagon pattern occurs in the short wavelength mode layer and a stripe pattern appears in the long wavelength mode layer, the Hopf instability may happen in a nonlinearly coupled model, and twinkling-eye hexagon and travelling hexagon patterns will be obtained. The symmetries of patterns resulting from the coupled modes may be different from those of their parents, such as the cluster hexagon pattern and square pattern. With the increase of perturbation and coupling intensity, the nonlinear system will con-vert between a static pattern and a dynamic pattern when the Turing instability and Hopf instability happen in the nonlinear system. Besides the wavenumber ratio and intensity ratio of the two different wavelength Turing modes, perturbation and coupling intensity play an important role in the pattern formation and selection. According to the simulation results, we find that two modes with different symmetries can also be in the spatial resonance under certain conditions, and complex patterns appear in the two-layer coupled reaction diffusion systems.

  5. Two-Layer Tight Frame Sparsifying Model for Compressed Sensing Magnetic Resonance Imaging (United States)

    Peng, Xi; Dong, Pei


    Compressed sensing magnetic resonance imaging (CSMRI) employs image sparsity to reconstruct MR images from incoherently undersampled K-space data. Existing CSMRI approaches have exploited analysis transform, synthesis dictionary, and their variants to trigger image sparsity. Nevertheless, the accuracy, efficiency, or acceleration rate of existing CSMRI methods can still be improved due to either lack of adaptability, high complexity of the training, or insufficient sparsity promotion. To properly balance the three factors, this paper proposes a two-layer tight frame sparsifying (TRIMS) model for CSMRI by sparsifying the image with a product of a fixed tight frame and an adaptively learned tight frame. The two-layer sparsifying and adaptive learning nature of TRIMS has enabled accurate MR reconstruction from highly undersampled data with efficiency. To solve the reconstruction problem, a three-level Bregman numerical algorithm is developed. The proposed approach has been compared to three state-of-the-art methods over scanned physical phantom and in vivo MR datasets and encouraging performances have been achieved. PMID:27747226

  6. Analysis and Control of Two-Layer Frenkel-Kontorova Model

    Institute of Scientific and Technical Information of China (English)

    TANG Wen-Yan; QU Zhi-Hua; GUO Yi


    A one-dimensional two-layer Frenkel-Kontorova model is studied.Firstly,a feedback tracking control law is given.Then,the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method.Especially,the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity.Simulations illustrate the accuracy of the derived results.Recently,the Frenkel-Kontorova (FK) model,which describes a chain of classical particles interacting with its nearest neighbors and subjected to a periodic one-site potential,has become a useful tool to study nanotribology.[1-6] There are several generalizations of the FK model that have been introduced with the hope of understanding friction dynamics at nanoscale.These models include a manylayer model with harmonic interactions,the FrenkelKontorova-Tomlinson model (FKT) and the singlelayer model with harmonic interactions.%A one-dimensional two-layer Frenkel-Kontorova model is studied. Firstly, a feedback tracking control law is given. Then, the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method. Especially, the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity. Simulations illustrate the accuracy of the derived results.

  7. Reverse-feeding effect of epidemic by propagators in two-layered networks (United States)

    Dayu, Wu; Yanping, Zhao; Muhua, Zheng; Jie, Zhou; Zonghua, Liu


    Epidemic spreading has been studied for a long time and is currently focused on the spreading of multiple pathogens, especially in multiplex networks. However, little attention has been paid to the case where the mutual influence between different pathogens comes from a fraction of epidemic propagators, such as bisexual people in two separated groups of heterosexual and homosexual people. We here study this topic by presenting a network model of two layers connected by impulsive links, in contrast to the persistent links in each layer. We let each layer have a distinct pathogen and their interactive infection is implemented by a fraction of propagators jumping between the corresponding pairs of nodes in the two layers. By this model we show that (i) the propagators take the key role to transmit pathogens from one layer to the other, which significantly influences the stabilized epidemics; (ii) the epidemic thresholds will be changed by the propagators; and (iii) a reverse-feeding effect can be expected when the infective rate is smaller than its threshold of isolated spreading. A theoretical analysis is presented to explain the numerical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11135001, 11375066, and 11405059) and the National Basic Key Program of China (Grant No. 2013CB834100).


    Institute of Scientific and Technical Information of China (English)


    Gully erosion is one of the main causes of top soil loss, land deterioration and sources of sediment deposition in streams. Headcut often occurs in the gully erosion process when erodability of the soil layers varies, and the gully cuts through a hard layer at a point. A scouring hole appears downstream of the head cut which migrates upstream due to strong erosion in the scour hole. This paper presents numerical analyses of turbulent flow and sediment transport processes of a head-cut associated with a two-layer soil stratigraphic formation. The flow in the scour hole is three-dimensional induced by the water jet from the brink of the top layer; the sediment transport model considers sediment entrainment by the impinging jet, erosion underneath the hard layer and the retreat of the brink of the hard layer. The 3D flow simulation in the scour hole and the scouring process was verified with physical model data. The two-layer head cut migration is simulated with different flow and soil parameters, the trends of the simulated results reasonably revealed contributions of these parameters to the scouring and migration process.

  9. Two-layer wireless distributed sensor/control network based on RF (United States)

    Feng, Li; Lin, Yuchi; Zhou, Jingjing; Dong, Guimei; Xia, Guisuo


    A project of embedded Wireless Distributed Sensor/Control Network (WDSCN) based on RF is presented after analyzing the disadvantages of traditional measure and control system. Because of high-cost and complexity, such wireless techniques as Bluetooth and WiFi can't meet the needs of WDSCN. The two-layer WDSCN is designed based on RF technique, which operates in the ISM free frequency channel with low power and high transmission speed. Also the network is low cost, portable and moveable, integrated with the technologies of computer network, sensor, microprocessor and wireless communications. The two-layer network topology is selected in the system; a simple but efficient self-organization net protocol is designed to fit the periodic data collection, event-driven and store-and-forward. Furthermore, adaptive frequency hopping technique is adopted for anti-jamming apparently. The problems about power reduction and synchronization of data in wireless system are solved efficiently. Based on the discussion above, a measure and control network is set up to control such typical instruments and sensors as temperature sensor and signal converter, collect data, and monitor environmental parameters around. This system works well in different rooms. Experiment results show that the system provides an efficient solution to WDSCN through wireless links, with high efficiency, low power, high stability, flexibility and wide working range.

  10. Molecular Cloning of a cDNA Encoding for Taenia solium TATA-Box Binding Protein 1 (TsTBP1) and Study of Its Interactions with the TATA-Box of Actin 5 and Typical 2-Cys Peroxiredoxin Genes. (United States)

    Rodríguez-Lima, Oscar; García-Gutierrez, Ponciano; Jiménez, Lucía; Zarain-Herzberg, Ángel; Lazzarini, Roberto; Landa, Abraham


    TATA-box binding protein (TBP) is an essential regulatory transcription factor for the TATA-box and TATA-box-less gene promoters. We report the cloning and characterization of a full-length cDNA that encodes a Taenia solium TATA-box binding protein 1 (TsTBP1). Deduced amino acid composition from its nucleotide sequence revealed that encodes a protein of 238 residues with a predicted molecular weight of 26.7 kDa, and a theoretical pI of 10.6. The NH2-terminal domain shows no conservation when compared with to pig and human TBP1s. However, it shows high conservation in size and amino acid identity with taeniids TBP1s. In contrast, the TsTBP1 COOH-terminal domain is highly conserved among organisms, and contains the amino acids involved in interactions with the TATA-box, as well as with TFIIA and TFIIB. In silico TsTBP1 modeling reveals that the COOH-terminal domain forms the classical saddle structure of the TBP family, with one α-helix at the end, not present in pig and human. Native TsTBP1 was detected in T. solium cysticerci´s nuclear extract by western blot using rabbit antibodies generated against two synthetic peptides located in the NH2 and COOH-terminal domains of TsTBP1. These antibodies, through immunofluorescence technique, identified the TBP1 in the nucleus of cells that form the bladder wall of cysticerci of Taenia crassiceps, an organism close related to T. solium. Electrophoretic mobility shift assays using nuclear extracts from T. solium cysticerci and antibodies against the NH2-terminal domain of TsTBP1 showed the interaction of native TsTBP1 with the TATA-box present in T. solium actin 5 (pAT5) and 2-Cys peroxiredoxin (Ts2-CysPrx) gene promoters; in contrast, when antibodies against the anti-COOH-terminal domain of TsTBP1 were used, they inhibited the binding of TsTBP1 to the TATA-box of the pAT5 promoter gene.

  11. Activation of silenced cytokine gene promoters by the synergistic effect of TBP-TALE and VP64-TALE activators.

    Directory of Open Access Journals (Sweden)

    Kim Anthony

    Full Text Available Recent work has shown that the combinatorial use of multiple TALE activators can selectively activate certain cellular genes in inaccessible chromatin regions. In this study, we aimed to interrogate the activation potential of TALEs upon transcriptionally silenced immune genes in the context of non-immune cells. We designed a unique strategy, in which a single TALE fused to the TATA-box binding protein (TBP-TALE is coupled with multiple VP64-TALE activators. We found that our strategy is significantly more potent than multiple TALE activators alone in activating expression of IL-2 and GM-CSF in diverse cell origins in which both genes are otherwise completely silenced. Chromatin analysis revealed that the gene activation was due in part to displacement of a distinctly positioned nucleosome. These studies provide a novel epigenetic mechanism for artificial gene induction and have important implications for targeted cancer immunotherapy, DNA vaccine development, as well as rational design of TALE activators.

  12. Activation of silenced cytokine gene promoters by the synergistic effect of TBP-TALE and VP64-TALE activators. (United States)

    Anthony, Kim; More, Abhijit; Zhang, Xiaoliu


    Recent work has shown that the combinatorial use of multiple TALE activators can selectively activate certain cellular genes in inaccessible chromatin regions. In this study, we aimed to interrogate the activation potential of TALEs upon transcriptionally silenced immune genes in the context of non-immune cells. We designed a unique strategy, in which a single TALE fused to the TATA-box binding protein (TBP-TALE) is coupled with multiple VP64-TALE activators. We found that our strategy is significantly more potent than multiple TALE activators alone in activating expression of IL-2 and GM-CSF in diverse cell origins in which both genes are otherwise completely silenced. Chromatin analysis revealed that the gene activation was due in part to displacement of a distinctly positioned nucleosome. These studies provide a novel epigenetic mechanism for artificial gene induction and have important implications for targeted cancer immunotherapy, DNA vaccine development, as well as rational design of TALE activators.

  13. Using FRET to Measure the Angle at Which a Protein Bends DNA: TBP Binding a TATA Box as a Model System (United States)

    Kugel, Jennifer F.


    An undergraduate biochemistry laboratory experiment that will teach the technique of fluorescence resonance energy transfer (FRET) while analyzing protein-induced DNA bending is described. The experiment uses the protein TATA binding protein (TBP), which is a general transcription factor that recognizes and binds specific DNA sequences known as…

  14. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC; Determinacion Espectrofotometrica de Microcantidades de Uranio previa extraccin con Metilisobutilcetona-Fosfato de Tributilo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement, J.; Fernandez Cellini, R.


    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs.

  15. Formation of new lipoaminopeptides, acremostatins A, B, and C, by co-cultivation of Acremonium sp. Tbp-5 and Mycogone rosea DSM 12973. (United States)

    Degenkolb, Thomas; Heinze, Stephan; Schlegel, Brigitte; Strobel, Gary; Gräfe, Udo


    Formation of new lipoaminopeptides, acremostatins A, B, and C, was observed during co-cultivation of Acremonium sp. Tbp-5 and Mycogone rosea DSM 12973. Thus, co-cultivation of microorganisms producing related products could be suggested as a suitable way towards diversification of microbial structures.

  16. Wave turbulence in a two-layer fluid: coupling between free surface and interface waves

    CERN Document Server

    Issenmann, Bruno; Falcon, Eric


    We experimentally study gravity-capillary wave turbulence on the interface between two immiscible fluids of close density with free upper surface. We locally measure the wave height at the interface between both fluids by means of a highly sensitive laser Doppler vibrometer. We show that the inertial range of the capillary wave turbulence regime is significantly extended when the upper fluid depth is increased: The crossover frequency between the gravity and capillary wave turbulence regimes is found to decrease whereas the dissipative cut-off frequency of the spectrum is found to increase. We explain most of these observations by the progressive decoupling between waves propagating at the interface and the ones at the free surface, using the full dispersion relation of gravity-capillary waves in a two-layer fluid of finite depths.s.

  17. Spin-3/2 Ising model AFM/AFM two-layer lattice with crystal field

    Institute of Scientific and Technical Information of China (English)

    Erhan Albayrak; Ali Yigit


    The spin-3/2 Ising model is investigated for the case of antiferromagnetic (AFM/AFM) interactions on the two-layer Bethe lattice by using the exact recursion relations in the pairwise approach for given coordination numbers q = 3, 4 and 6 when the layers are under the influences of equal external magnetic and equal crystal fields. The ground state, (GS) phase diagrams are obtained on the different planes in detail and then the temperature-dependent phase diagrams of the system are calculated accordingly. It is observed that the system presents both second- and first-order phase transitions for all q, therefore, tricritical points. It is also found that the system exhibits double-critical end points and isolated points. The model aiso presents two Néel temperatures, T_N, and the existence of which leads to the reentrant behaviour.

  18. Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach (United States)

    Camassa, R.; Falqui, G.; Ortenzi, G.


    The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite two-dimensional channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids’ inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, albeit in a non-trivial way. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, a family of approximate constants of the motion are explicitly constructed and used to find local solutions of the evolution equations by means of hodograph-like formulae.

  19. Central-Upwind Schemes for Two-Layer Shallow Water Equations

    KAUST Repository

    Kurganov, Alexander


    We derive a second-order semidiscrete central-upwind scheme for one- and two-dimensional systems of two-layer shallow water equations. We prove that the presented scheme is well-balanced in the sense that stationary steady-state solutions are exactly preserved by the scheme and positivity preserving; that is, the depth of each fluid layer is guaranteed to be nonnegative. We also propose a new technique for the treatment of the nonconservative products describing the momentum exchange between the layers. The performance of the proposed method is illustrated on a number of numerical examples, in which we successfully capture (quasi) steady-state solutions and propagating interfaces. © 2009 Society for Industrial and Applied Mathematics.

  20. Two-layer fragile watermarking method secured with chaotic map for authentication of digital Holy Quran. (United States)

    Khalil, Mohammed S; Kurniawan, Fajri; Khan, Muhammad Khurram; Alginahi, Yasser M


    This paper presents a novel watermarking method to facilitate the authentication and detection of the image forgery on the Quran images. Two layers of embedding scheme on wavelet and spatial domain are introduced to enhance the sensitivity of fragile watermarking and defend the attacks. Discrete wavelet transforms are applied to decompose the host image into wavelet prior to embedding the watermark in the wavelet domain. The watermarked wavelet coefficient is inverted back to spatial domain then the least significant bits is utilized to hide another watermark. A chaotic map is utilized to blur the watermark to make it secure against the local attack. The proposed method allows high watermark payloads, while preserving good image quality. Experiment results confirm that the proposed methods are fragile and have superior tampering detection even though the tampered area is very small.

  1. Transient response of a vertical electric dipole (VED) on a two-layer medium (United States)

    Poh, S. Y.; Kong, J. A.

    The transient electromagnetic radiation by a vertical electric dipole on a two-layer medium is analyzed using the double deformation technique, which is a modal technique based on identification of singularities in the complex frequency and wavenumber planes. Previous application of the double deformation technique to the solution of this problem is incomplete in the early time response. In this paper it is shown that the existence of a pole locus on the negative imaginary frequency axis, which dominates the early time response, proves crucial in obtaining the solution for all times. A variety of combinations of parameters are used to illustrate the double deformation technique, and results will be compared with those obtained via explicit inversion, and a single deformation method.

  2. Two-Layer Coding Rate Optimization in Relay-Aided Systems

    DEFF Research Database (Denmark)

    Sun, Fan


    We consider a three-node transmission system, where a source node conveys a data block to a destination node with the help of a half-duplex decode and-forward (DF) relay node. The whole data block is transmitted as a sequence of packets. For reliable transmission in the three-node system, a two......-layer coding scheme is proposed, where physical layer channel coding is utilized within each packet for error-correction and random network coding is applied on top of channel coding for network error-control. There is a natural tradeoff between the physical layer coding rate and the network coding rate given...... requirement. Numerical results are also provided to show the optimized physical layer coding and network coding rate pairs in different system scenarios....

  3. The peak effect (PE) region of the antiferromagnetic two layer Ising nanographene

    Energy Technology Data Exchange (ETDEWEB)

    Şarlı, Numan, E-mail: [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Akbudak, Salih [Department of Physics, Adiyaman University, 02100 Adiyaman (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, 06800 Ankara (Turkey); Ellialtıoğlu, Mehmet Recai [Department of Physics Engineering, Hacettepe University, 06800 Ankara (Turkey)


    In this work, the magnetic properties of the ferromagnetic and antiferromagnetic two layer spin-1/2 Ising nanographene systems are investigated within the effective field theory. We find that the magnetizations and the hysteresis behaviors of the central graphene atoms are similar to those of the edge graphene atoms in the ferromagnetic case. But, they are quite different in the antiferromagnetic case. The antiferromagnetic central graphene atoms exhibit type II superconductivity and they have triple hysteresis loop. The peak effect (PE) region is observed on the hysteresis curves of the antiferromagnetic Ising nanographene system. Therefore, we suggest that there is a strong relationship between the antiferromagnetism and the peak effect. Our results are in agreement with some experimental works in recent literature.


    Directory of Open Access Journals (Sweden)



    Full Text Available Multilayer pressure vessel is designed to work under high-pressure condition. This paper introduces the stress analysis and the burst pressure calculation of a two-layer shrink fitted pressure vessel. In the shrink-fitting problems, considering long hollow cylinders, the plane strain hypothesis can be regarded as more natural. Generally hoops stress distribution is non-linear and sharply reduced toward the outer surface. By shrink fitting concentric shells towards the inner shells are placed in residual compression so that the initial compressive hoop stress must be relieved by internal pressure before hoop tensile stress are developed. Therefore the maximum hoop stress will be reduced, resulting more burst pressure. The analytical results of stress distribution and burst pressure is calculated and validated by ANSYS Workbench results.

  5. Testing the Two-Layer Model for Correcting Clear Sky Reflectance near Clouds (United States)

    Wen, Guoyong; Marshak, Alexander; Evans, Frank; Varnai, Tamas; Levy, Rob


    A two-layer model (2LM) was developed in our earlier studies to estimate the clear sky reflectance enhancement due to cloud-molecular radiative interaction at MODIS at 0.47 micrometers. Recently, we extended the model to include cloud-surface and cloud-aerosol radiative interactions. We use the LES/SHDOM simulated 3D true radiation fields to test the 2LM for reflectance enhancement at 0.47 micrometers. We find: The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; the cloud-molecular interaction alone accounts for 70 percent of the enhancement; the cloud-surface interaction accounts for 16 percent of the enhancement; the cloud-aerosol interaction accounts for an additional 13 percent of the enhancement. We conclude that the 2LM is simple to apply and unbiased.

  6. Study of electronic and optical properties of two-layered hydrogenated aluminum nitrate nanosheet (United States)

    Faghihzadeh, Somayeh; Shahtahmasebi, Nasser; Rezaee Roknabadi, Mahmood


    First principle calculations based on density functional theory using GW approximation and two particle Bethe-Salpeter equation with electron-hole effect were performed to investigate electronic structure and optical properties of two-layered hydrogenated AlN. According to many body green function due to decrease in dimension and considering electron-electron effect, direct (indirect) band gap change from 2 (1.01) eV to 4.83 (3.62) eV. The first peak in imaginary part of dielectric function was observed in parallel direction to a plane obtaining 3.4 was achieved by bound exciton states possess 1.39 eV. The first absorption peak was seen in two parallel and perpendicular directions to a plane which are in UV region.

  7. Initial stresses in two-layer metal domes due to imperfections of their production and assemblage

    Directory of Open Access Journals (Sweden)

    Lebed Evgeniy Vasil’evich


    Full Text Available The process of construction of two-layer metal domes is analyzed to illustrate the causes of initial stresses in the bars of their frames. It has been noticed that it is impossible to build such structures with ideal geometric parameters because of imperfections caused by objective reasons. These imperfections cause difficulties in the process of connection of the elements in the joints. The paper demonstrates the necessity of fitting operations during assemblage that involve force fitting and yield initial stresses due to imperfections. The authors propose a special method of computer modeling of enforced elimination of possible imperfections caused by assemblage process and further confirm the method by an analysis of a concrete metal dome.

  8. Analysis of data recorded by the LCTPC equipped with a two layer GEM-system

    CERN Document Server

    Ljunggren, M


    wire based readout. The prototype TPC is placed in a 1 Tesla magnet at DESY and tested using an electron beam. Analyses of data taken during two different measurement series, in 2009 and 2010, are presented here. The TPC was instrumented with a two layer GEM system and read out using modified electronics from the ALICE experiment, including the programmable charge sensitive preamp-shaper PCA16. The PCA16 chip has a number of programmable parameters which allows studies to determine the settings optimal to the final TPC. Here, the impact of the shaping time on the space resolution in the drift direction was studied. It was found that a shaping time of 60 ns is the b...


    Directory of Open Access Journals (Sweden)

    Jelena M Djoković


    Full Text Available In this paper is considered a problem of the semi-infinite crack at the interface between the two elastic isotropic layers in conditions of the environmental temperature change. The energy release rate needed for the crack growth along the interface was determined, for the case when the two-layered sample is cooled from the temperature of the layers joining down to the room temperature. It was noticed that the energy release rate increases with the temperature difference increase. In the paper is also presented the distribution of stresses in layers as a function of the temperature and the layers' thickness variations. Analysis is limited to the case when the bimaterial sample is exposed to uniform temperature.

  10. High Performance Hybrid Two Layer Router Architecture for FPGAs Using Network On Chip

    CERN Document Server

    Ezhumalai, P; Arun, C; Sakthivel, P; Sridharan, D


    Networks on Chip is a recent solution paradigm adopted to increase the performance of Multicore designs. The key idea is to interconnect various computation modules (IP cores) in a network fashion and transport packets simultaneously across them, thereby gaining performance. In addition to improving performance by having multiple packets in flight, NoCs also present a host of other advantages including scalability, power efficiency, and component reuse through modular design. This work focuses on design and development of high performance communication architectures for FPGAs using NoCs Once completely developed, the above methodology could be used to augment the current FPGA design flow for implementing multicore SoC applications. We design and implement an NoC framework for FPGAs, MultiClock OnChip Network for Reconfigurable Systems (MoCReS). We propose a novel microarchitecture for a hybrid two layer router that supports both packetswitched communications, across its local and directional ports, as well as...

  11. The fuzzy coat of pathological human Tau fibrils is a two-layered polyelectrolyte brush. (United States)

    Wegmann, Susanne; Medalsy, Izhar D; Mandelkow, Eckhard; Müller, Daniel J


    The structure and properties of amyloid-like Tau fibrils accumulating in neurodegenerative diseases have been debated for decades. Although the core of Tau fibrils assembles from short β-strands, the properties of the much longer unstructured Tau domains protruding from the fibril core remain largely obscure. Applying immunogold transmission EM, and force-volume atomic force microscopy (AFM), we imaged human Tau fibrils at high resolution and simultaneously mapped their mechanical and adhesive properties. Tau fibrils showed a ≈ 16-nm-thick fuzzy coat that resembles a two-layered polyelectrolyte brush, which is formed by the unstructured short C-terminal and long N-terminal Tau domains. The mechanical and adhesive properties of the fuzzy coat are modulated by electrolytes and pH, and thus by the cellular environment. These unique properties of the fuzzy coat help in understanding how Tau fibrils disturb cellular interactions and accumulate in neurofibrillary tangles.

  12. Sparse/DCT (S/DCT) two-layered representation of prediction residuals for video coding. (United States)

    Kang, Je-Won; Gabbouj, Moncef; Kuo, C-C Jay


    In this paper, we propose a cascaded sparse/DCT (S/DCT) two-layer representation of prediction residuals, and implement this idea on top of the state-of-the-art high efficiency video coding (HEVC) standard. First, a dictionary is adaptively trained to contain featured patterns of residual signals so that a high portion of energy in a structured residual can be efficiently coded via sparse coding. It is observed that the sparse representation alone is less effective in the R-D performance due to the side information overhead at higher bit rates. To overcome this problem, the DCT representation is cascaded at the second stage. It is applied to the remaining signal to improve coding efficiency. The two representations successfully complement each other. It is demonstrated by experimental results that the proposed algorithm outperforms the HEVC reference codec HM5.0 in the Common Test Condition.

  13. Development of an algebraic stress/two-layer model for calculating thrust chamber flow fields (United States)

    Chen, C. P.; Shang, H. M.; Huang, J.


    Following the consensus of a workshop in Turbulence Modeling for Liquid Rocket Thrust Chambers, the current effort was undertaken to study the effects of second-order closure on the predictions of thermochemical flow fields. To reduce the instability and computational intensity of the full second-order Reynolds Stress Model, an Algebraic Stress Model (ASM) coupled with a two-layer near wall treatment was developed. Various test problems, including the compressible boundary layer with adiabatic and cooled walls, recirculating flows, swirling flows and the entire SSME nozzle flow were studied to assess the performance of the current model. Detailed calculations for the SSME exit wall flow around the nozzle manifold were executed. As to the overall flow predictions, the ASM removes another assumption for appropriate comparison with experimental data, to account for the non-isotropic turbulence effects.

  14. Cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate

    Institute of Scientific and Technical Information of China (English)

    Xiang Yan-Xun; Deng Ming-Xi


    The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of acoustic waves at an interface.In general,the cumulative second-harmonic generation of a dispersive guided wave propagation does not occur.However,the present paper shows that the second-harmonic of Lamb wave propagation arising from the nonlinear interaction of the partial bulk acoustic waves and the restriction of the three boundaries of the solid plates does have a cumulative growth effect if some conditions are satisfied.Through boundary condition and initial condition of excitation,the analytical expression of cumulative second-harmonic of Lamb waves propagation is determined.Numerical results show the cumulative effect of Lamb waves on second-harmonic field patterns.

  15. Convergent flow in a two-layer system and mountain building

    CERN Document Server

    Perazzo, Carlos Alberto


    With the purpose of modelling the process of mountain building, we investigate the evolution of the ridge produced by the convergent motion of a system consisting of two layers of liquids that differ in density and viscosity to simulate the crust and the upper mantle that form a lithospheric plate. We assume that the motion is driven by basal traction. Assuming isostasy, we derive a nonlinear differential equation for the evolution of the thickness of the crust. We solve this equation numerically to obtain the profile of the range. We find an approximate self-similar solution that describes reasonably well the process and predicts simple scaling laws for the height and width of the range as well as the shape of the transversal profile. We compare the theoretical results with the profiles of real mountain belts and find and excellent agreement.


    Directory of Open Access Journals (Sweden)

    Sen-Tarng Lai


    Full Text Available E-commerce is an important information system in the network and digital age. However, the network intrusion, malicious users, virus attack and system security vulnerabilities have continued to threaten the operation of the e-commerce, making e-commerce security encounter serious test. How to improve ecommerce security has become a topic worthy of further exploration. Combining routine security test and security event detection procedures, this paper proposes the Two-Layer Secure Prevention Mechanism (TLSPM. Applying TLSPM, routine security test procedure can identify security vulnerability and defect, and develop repair operations. Security event detection procedure can timely detect security event, and assist follow repair. TLSPM can enhance the e-commerce security and effectively reduce the security risk of e-commerce critical data and asset.

  17. Calculation of AC loss in two-layer superconducting cable with equal currents in the layers (United States)

    Erdogan, Muzaffer


    A new method for calculating AC loss of two-layer SC power transmission cables using the commercial software Comsol Multiphysics, relying on the approach of the equal partition of current between the layers is proposed. Applying the method to calculate the AC-loss in a cable composed of two coaxial cylindrical SC tubes, the results are in good agreement with the analytical ones of duoblock model. Applying the method to calculate the AC-losses of a cable composed of a cylindrical copper former, surrounded by two coaxial cylindrical layers of superconducting tapes embedded in an insulating medium with tape-on-tape and tape-on-gap configurations are compared. A good agreement between the duoblock model and the numerical results for the tape-on-gap cable is observed.

  18. 2-DE combined with two-layer feature selection accurately establishes the origin of oolong tea. (United States)

    Chien, Han-Ju; Chu, Yen-Wei; Chen, Chi-Wei; Juang, Yu-Min; Chien, Min-Wei; Liu, Chih-Wei; Wu, Chia-Chang; Tzen, Jason T C; Lai, Chien-Chen


    Taiwan is known for its high quality oolong tea. Because of high consumer demand, some tea manufactures mix lower quality leaves with genuine Taiwan oolong tea in order to increase profits. Robust scientific methods are, therefore, needed to verify the origin and quality of tea leaves. In this study, we investigated whether two-dimensional gel electrophoresis (2-DE) and nanoscale liquid chromatography/tandem mass spectroscopy (nano-LC/MS/MS) coupled with a two-layer feature selection mechanism comprising information gain attribute evaluation (IGAE) and support vector machine feature selection (SVM-FS) are useful in identifying characteristic proteins that can be used as markers of the original source of oolong tea. Samples in this study included oolong tea leaves from 23 different sources. We found that our method had an accuracy of 95.5% in correctly identifying the origin of the leaves. Overall, our method is a novel approach for determining the origin of oolong tea leaves.

  19. A Two-Layer Mathematical Modelling of Drug Delivery to Biological Tissues

    CERN Document Server

    Chakravarty, Koyel


    Local drug delivery has received much recognition in recent years, yet it is still unpredictable how drug efficacy depends on physicochemical properties and delivery kinetics. The purpose of the current study is to provide a useful mathematical model for drug release from a drug delivery device and consecutive drug transport in biological tissue, thereby aiding the development of new therapeutic drug by a systemic approach. In order to study the complete process, a two-layer spatio-temporal model depicting drug transport between the coupled media is presented. Drug release is described by considering solubilisation dynamics of drug particle, diffusion of the solubilised drug through porous matrix and also some other processes like reversible dissociation / recrystallization, drug particle-receptor binding and internalization phenomena. The model has led to a system of partial differential equations describing the important properties of drug kinetics. This model contributes towards the perception of the roles...

  20. Some considerations on numerical schemes for treating hyperbolicity issues in two-layer models (United States)

    Sarno, L.; Carravetta, A.; Martino, R.; Papa, M. N.; Tai, Y.-C.


    Multi-layer depth-averaged models are widely employed in various hydraulic engineering applications. Yet, such models are not strictly hyperbolic. Their equation systems typically lose hyperbolicity when the relative velocities between layers become too large, which is associated with Kelvin-Helmholtz instabilities involving turbulent momentum exchanges between the layers. Focusing on the two-layer case, we present a numerical improvement that locally avoids the loss of hyperbolicity. The proposed modification introduces an additional momentum exchange between layers, whose value is iteratively calculated to be strictly sufficient to keep the system hyperbolic. The approach can be easily implemented in any finite volume scheme and there is no limitation concerning the density ratio between layers. Numerical examples, employing both HLL-type and Roe-type approximate Riemann solvers, are reported to validate the method and its key features.


    Institute of Scientific and Technical Information of China (English)

    Liu Shidong; Zhang Shunyi; Zhou Jinquan; Qiu Gong'an


    Overlay multicast has become one of the most promising multicast solutions for IP network, and Neutral Network(NN) has been a good candidate for searching optimal solutions to the constrained shortest routing path in virtue of its powerful capacity for parallel computation. Though traditional Hopfield NN can tackle the optimization problem, it is incapable of dealing with large scale networks due to the large number of neurons. In this paper, a neural network for overlay multicast tree computation is presented to reliably implement routing algorithm in real time. The neural network is constructed as a two-layer recurrent architecture, which is comprised of Independent Variable Neurons (IDVN) and Dependent Variable Neurons (DVN), according to the independence of the decision variables associated with the edges in directed graph. Compared with the heuristic routing algorithms, it is characterized as shorter computational time, fewer neurons, and better precision.

  2. Two-layer networked learning control using self-learning fuzzy control algorithms

    Institute of Scientific and Technical Information of China (English)


    Since the existing single-layer networked control systems have some inherent limitations and cannot effectively handle the problems associated with unreliable networks, a novel two-layer networked learning control system (NLCS) is proposed in this paper. Its lower layer has a number of local controllers that are operated independently, and its upper layer has a learning agent that communicates with the independent local controllers in the lower layer. To implement such a system, a packet-discard strategy is firstly developed to deal with network-induced delay and data packet loss. A cubic spline interpolator is then employed to compensate the lost data. Finally, the output of the learning agent based on a novel radial basis function neural network (RBFNN) is used to update the parameters of fuzzy controllers. A nonlinear heating, ventilation and air-conditioning (HVAC) system is used to demonstrate the feasibility and effectiveness of the proposed system.

  3. Artery buckling analysis using a two-layered wall model with collagen dispersion. (United States)

    Mottahedi, Mohammad; Han, Hai-Chao


    Artery buckling has been proposed as a possible cause for artery tortuosity associated with various vascular diseases. Since microstructure of arterial wall changes with aging and diseases, it is essential to establish the relationship between microscopic wall structure and artery buckling behavior. The objective of this study was to developed arterial buckling equations to incorporate the two-layered wall structure with dispersed collagen fiber distribution. Seven porcine carotid arteries were tested for buckling to determine their critical buckling pressures at different axial stretch ratios. The mechanical properties of these intact arteries and their intima-media layer were determined via pressurized inflation test. Collagen alignment was measured from histological sections and modeled by a modified von-Mises distribution. Buckling equations were developed accordingly using microstructure-motivated strain energy function. Our results demonstrated that collagen fibers disperse around two mean orientations symmetrically to the circumferential direction (39.02°±3.04°) in the adventitia layer; while aligning closely in the circumferential direction (2.06°±3.88°) in the media layer. The microstructure based two-layered model with collagen fiber dispersion described the buckling behavior of arteries well with the model predicted critical pressures match well with the experimental measurement. Parametric studies showed that with increasing fiber dispersion parameter, the predicted critical buckling pressure increases. These results validate the microstructure-based model equations for artery buckling and set a base for further studies to predict the stability of arteries due to microstructural changes associated with vascular diseases and aging.

  4. Quantification of the specific yield in a two-layer hard-rock aquifer model (United States)

    Durand, Véronique; Léonardi, Véronique; de Marsily, Ghislain; Lachassagne, Patrick


    Hard rock aquifers (HRA) have long been considered to be two-layer systems, with a mostly capacitive layer just below the surface, the saprolite layer, and a mainly transmissive layer underneath, the fractured layer. Although this hydrogeological conceptual model is widely accepted today within the scientific community, it is difficult to quantify the respective storage properties of each layer with an equivalent porous medium model. Based on an HRA field site, this paper attempts to quantify in a distinct manner the respective values of the specific yield (Sy) in the saprolite and the fractured layer, with the help of a deterministic hydrogeological model. The study site is the Plancoët migmatitic aquifer located in north-western Brittany, France, with piezometric data from 36 observation wells surveyed every two weeks for eight years. Whereas most of the piezometers (26) are located where the water table lies within the saprolite, thus representing the specific yield of the unconfined layer (Sy1), 10 of them are representative of the unconfined fractured layer (Sy2), due to their position where the saprolite is eroded or unsaturated. The two-layer model, based on field observations of the layer geometry, runs with the MODFLOW code. 81 values of the Sy1/Sy2 parameter sets were tested manually, as an inverse calibration was not able to calibrate these parameters. In order to calibrate the storage properties, a new quality-of-fit criterion called ;AdVar; was also developed, equal to the mean squared deviation of the seasonal piezometric amplitude variation. Contrary to the variance, AdVar is able to select the best values for the specific yield in each layer. It is demonstrated that the saprolite layer is about 2.5 times more capacitive than the fractured layer, with Sy1 = 10% (7% < Sy1 < 15%) against Sy2 = 2% (1% < Sy2 < 3%), in this particular example.

  5. Single- and Two-Layer Coatings of Metal Blends onto Carbon Steel: Mechanical, Wear, and Friction Characterizations (United States)

    Yilbas, Bekir Sami; Kumar, Aditya; Bhushan, Bharat


    Single- and two-layer coatings were deposited onto carbon steel using a high-velocity oxy-fuel deposition gun. The two-layer coating consisted of a top layer of tungsten carbide cobalt/nickel alloy blend that provides wear resistance and a bottom layer of iron/molybdenum blend that provides corrosion resistance. The morphological changes in the single- and two-layer coatings were examined using scanning electron microscopy. The residual stresses formed on the surface of various coatings were determined from x-ray diffraction data. Nanomechanical properties were measured using the nanoindentation technique. Microhardness and fracture toughness were measured incorporating the microindentation tests. Macrowear and macrofriction characteristics were measured using the pin-on-disk testing apparatus. The goal of this study was to ensure that the mechanical properties, friction, and wear resistance of the two-layer coating are similar to that of the single-layer coating.

  6. Storage capacity and learning algorithms for two-layer neural networks (United States)

    Engel, A.; Köhler, H. M.; Tschepke, F.; Vollmayr, H.; Zippelius, A.


    A two-layer feedforward network of McCulloch-Pitts neurons with N inputs and K hidden units is analyzed for N-->∞ and K finite with respect to its ability to implement p=αN random input-output relations. Special emphasis is put on the case where all hidden units are coupled to the output with the same strength (committee machine) and the receptive fields of the hidden units either enclose all input units (fully connected) or are nonoverlapping (tree structure). The storage capacity is determined generalizing Gardner's treatment [J. Phys. A 21, 257 (1988); Europhys. Lett. 4, 481 (1987)] of the single-layer perceptron. For the treelike architecture, a replica-symmetric calculation yields αc~ √K for a large number K of hidden units. This result violates an upper bound derived by Mitchison and Durbin [Biol. Cybern. 60, 345 (1989)]. One-step replica-symmetry breaking gives lower values of αc. In the fully connected committee machine there are in general correlations among different hidden units. As the limit of capacity is approached, the hidden units are anticorrelated: One hidden unit attempts to learn those patterns which have not been learned by the others. These correlations decrease as 1/K, so that for K-->∞ the capacity per synapse is the same as for the tree architecture, whereas for small K we find a considerable enhancement for the storage per synapse. Numerical simulations were performed to explicitly construct solutions for the tree as well as the fully connected architecture. A learning algorithm is suggested. It is based on the least-action algorithm, which is modified to take advantage of the two-layer structure. The numerical simulations yield capacities p that are slightly more than twice the number of degrees of freedom, while the fully connected net can store relatively more patterns than the tree. Various generalizations are discussed. Variable weights from hidden to output give the same results for the storage capacity as does the committee

  7. Optical measurements of absorption changes in two-layered diffusive media

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Francesco [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Sassaroli, Angelo [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Henry, Michael E [McLean Hospital and Department of Psychiatry, Harvard Medical School, 115 Mill Street, Belmont, MA 02478 (United States); Fantini, Sergio [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States)


    We have used Monte Carlo simulations for a two-layered diffusive medium to investigate the effect of a superficial layer on the measurement of absorption variations from optical diffuse reflectance data processed by using: (a) a multidistance, frequency-domain method based on diffusion theory for a semi-infinite homogeneous medium; (b) a differential-pathlength-factor method based on a modified Lambert-Beer law for a homogeneous medium and (c) a two-distance, partial-pathlength method based on a modified Lambert-Beer law for a two-layered medium. Methods (a) and (b) lead to a single value for the absorption variation, whereas method (c) yields absorption variations for each layer. In the simulations, the optical coefficients of the medium were representative of those of biological tissue in the near-infrared. The thickness of the first layer was in the range 0.3-1.4 cm, and the source-detector distances were in the range 1-5 cm, which is typical of near-infrared diffuse reflectance measurements in tissue. The simulations have shown that (1) method (a) is mostly sensitive to absorption changes in the underlying layer, provided that the thickness of the superficial layer is {approx}0.6 cm or less; (2) method (b) is significantly affected by absorption changes in the superficial layer and (3) method (c) yields the absorption changes for both layers with a relatively good accuracy of {approx}4% for the superficial layer and {approx}10% for the underlying layer (provided that the absorption changes are less than 20-30% of the baseline value). We have applied all three methods of data analysis to near-infrared data collected on the forehead of a human subject during electroconvulsive therapy. Our results suggest that the multidistance method (a) and the two-distance partial-pathlength method (c) may better decouple the contributions to the optical signals that originate in deeper tissue (brain) from those that originate in more superficial tissue layers.

  8. A replication study for genome-wide gene expression levels in two layer lines elucidates differentially expressed genes of pathways involved in bone remodeling and immune responsiveness.

    Directory of Open Access Journals (Sweden)

    Christin Habig

    Full Text Available The current replication study confirmed significant differences in gene expression profiles of the cerebrum among the two commercial layer lines Lohmann Selected Leghorn (LSL and Lohmann Brown (LB. Microarray analyses were performed for 30 LSL and another 30 LB laying hens kept in the small group housing system Eurovent German. A total of 14,103 microarray probe sets using customized Affymetrix ChiGene-1_0-st Arrays with 20,399 probe sets were differentially expressed among the two layer lines LSL and LB (FDR adjusted P-value <0.05. An at least 2-fold change in expression levels could be observed for 388 of these probe sets. In LSL, 214 of the 388 probe sets were down- and 174 were up-regulated and vice versa for the LB layer line. Among the 174 up-regulated probe sets in LSL, we identified 51 significantly enriched Gene ontology (GO terms of the biological process category. A total of 63 enriched GO-terms could be identified for the 214 down-regulated probe sets of the layer line LSL. We identified nine genes significantly differentially expressed between the two layer lines in both microarray experiments. These genes play a crucial role in protection of neuronal cells from oxidative stress, bone mineral density and immune response among the two layer lines LSL and LB. Thus, the different regulation of these genes may significantly contribute to phenotypic trait differences among these layer lines. In conclusion, these novel findings provide a basis for further research to improve animal welfare in laying hens and these layer lines may be of general interest as an animal model.

  9. Recuperação de cádmio de baterias níquel-cádmio via extração seletiva com tributilfosfato (TBP Recovery of cadmium from nickel-cadmium batteries via selective extraction with tributylphosphate (TBP

    Directory of Open Access Journals (Sweden)

    Ana Paula Mauro Gonçalves Barandas


    Full Text Available This work describes a recovery process of cadmium from spent nickel-cadmium batteries by a new hydrometallurgical route based on the selective extraction in hydrochloric acid medium with tributylphosphate (TBP, alone or dissolved in kerosene. The best results were obtained when TBP concentration was at least 75 vol%. Nickel extraction was negligible under these conditions. It was isolated after processing the rafinate through an anionic ion-exchange column. Final wastes generated are basically sodium chloride solutions, with no turbidity, color or heavy metals present in significant amounts.

  10. Thermal properties of composite two-layer systems with a fractal inclusion structure (United States)

    Reyes-Salgado, J. J.; Dossetti, V.; Bonilla-Capilla, B.; Carrillo, J. L.


    In this work, we study the thermal transport properties of platelike composite two-layer samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy and thermal relaxation, their effective thermal diffusivity and conductivity were experimentally measured. The composite layers were prepared under the action of a static magnetic field, resulting in anisotropic (fractal) inclusion structures with the formation of chain-like magnetite aggregates parallel to the faces of the layers. In one kind of the bilayers, a composite layer was formed on top of a resin layer while their relative thickness was varied. These samples can be described by known models. In contrast, bilayers with the same concentration of inclusions and the same thickness on both sides, where only the angle between their inclusion structures was systematically varied, show a nontrivial behaviour of their thermal conductivity as a function of this angle. Through a multifractal and lacunarity analysis, we explain the observed thermal response in terms of the complexity of the interface between the layers.

  11. Two layer asymptotic model for the wave propagation in the presence of vorticity (United States)

    Kazakova, M. Yu; Noble, P.


    In the present study, we consider the system of two layers of the immiscible constant density fluids which are modeled by the full Euler equations. The domain of the flow is infinite in the horizontal directions and delimited above by a free surface. Bottom topography is taken into account. This is a simple model of the wave propagation in the ocean where the upper layer corresponds to the (thin) layer of fluid above the thermocline whereas the lower layer is under the thermocline. Though even this simple framework is computationally too expensive and mathematically too complicated to describe efficiently propagation of waves in the ocean. Modeling assumption such as shallowness, vanishing vorticity and hydrostatic pressure are usually made to get the bi-layer shallow water models that are mathematically more manageable. Though, they cannot describe correctly the propagation of both internal and free surface waves and dispersive/non hydrostatic must be added. Our goal is to consider the regime of medium to large vorticities in shallow water flow. We present the derivation of the model for internal and surface wave propagation in the case of constant and general vorticities in each layer. The model reduces to the classical Green-Naghdi equations in the case of vanishing vorticities.

  12. Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach

    CERN Document Server

    Camassa, R; Ortenzi, G


    The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite 2D channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids' inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, and thence, in a non-trivial way, to the dispersionless non-linear Schr\\"odinger equation. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, it is shown that at first order the deformed system possesses an infinite sequence of constants of the motion, thus casting this system within the framework of comp...

  13. Method of the Moulding Sands Binding Power Assessment in Two-Layer Moulds Systems

    Directory of Open Access Journals (Sweden)

    M. Holtzer


    Full Text Available More and more foundry plants applying moulding sands with water-glass or its substitutes for obtaining the high-quality casting surface at the smallest costs, consider the possibility of implementing two-layer moulds, in which e.g. the facing sand is a sand with an organic binder (no-bake type and the backing sand is a sand with inorganic binder. Both kinds of sands must have the same chemical reaction. The most often applied system is the moulding sand on the water-glass or geopolymer bases - as the backing sand and the moulding sand from the group of self-hardening sands with a resol resin - as the facing sand. Investigations were performed for the system: moulding sand with inorganic GEOPOL binder or moulding sand with water glass (as a backing sand and moulding sand, no-bake type, with a resol resin originated from various producers: Rezolit AM, Estrofen, Avenol NB 700 (as a facing sand. The LUZ apparatus, produced by Multiserw Morek, was adapted for investigations. A special partition with cuts was mounted in the attachment for making test specimens for measuring the tensile strength. This partition allowed a simultaneous compaction of two kinds of moulding sands. After 24 hours of hardening the highest values were obtained for the system: Geopol binder - Avenol resin.

  14. Display of the β-effect in the Black Sea Two-Layer Model

    Directory of Open Access Journals (Sweden)

    A.A. Pavlushin


    Full Text Available The research is a continuation of a series of numerical experiments on modeling formation of wind currents and eddies in the Black Sea within the framework of a two-layer eddy-resolving model. The main attention is focused on studying the β-effect role. The stationary cyclonic wind is used as an external forcing and the bottom topography is not considered. It is shown that at the β-effect being taken into account, the Rossby waves propagating from east to west are observed both during the currents’ formation and at the statistical equilibrium mode when the mesoscale eddies are formed. In the integral flows’ field the waves are visually manifested in a form of the alternate large-scale cyclonic gyres and zones in which the meso-scale anti-cyclones are formed. This spatial pattern constantly propagates to the west that differs from the results of calculations using the constant Coriolis parameter when the spatially alternate cyclonic and anti-cyclonic vortices are formed, but hold a quasi-stationary position. The waves with the parameters of the Rossby wave first barotropic mode for the closed basin are most clearly pronounced. Interaction of the Rossby waves with large-scale circulation results in intensification of the of the currents’ hydrodynamic instability and in formation of the mesoscale eddies. Significant decrease of kinetic and available potential energy as compared to the values obtained at the constant Coriolis parameter is also a consequence of the eddy formation intensification.

  15. Inferring topologies via driving-based generalized synchronization of two-layer networks (United States)

    Wang, Yingfei; Wu, Xiaoqun; Feng, Hui; Lu, Jun-an; Xu, Yuhua


    The interaction topology among the constituents of a complex network plays a crucial role in the network’s evolutionary mechanisms and functional behaviors. However, some network topologies are usually unknown or uncertain. Meanwhile, coupling delays are ubiquitous in various man-made and natural networks. Hence, it is necessary to gain knowledge of the whole or partial topology of a complex dynamical network by taking into consideration communication delay. In this paper, topology identification of complex dynamical networks is investigated via generalized synchronization of a two-layer network. Particularly, based on the LaSalle-type invariance principle of stochastic differential delay equations, an adaptive control technique is proposed by constructing an auxiliary layer and designing proper control input and updating laws so that the unknown topology can be recovered upon successful generalized synchronization. Numerical simulations are provided to illustrate the effectiveness of the proposed method. The technique provides a certain theoretical basis for topology inference of complex networks. In particular, when the considered network is composed of systems with high-dimension or complicated dynamics, a simpler response layer can be constructed, which is conducive to circuit design. Moreover, it is practical to take into consideration perturbations caused by control input. Finally, the method is applicable to infer topology of a subnetwork embedded within a complex system and locate hidden sources. We hope the results can provide basic insight into further research endeavors on understanding practical and economical topology inference of networks.

  16. Extreme events statistics in a two-layer quasi-geostrophic atmospheric model (United States)

    Galfi, Vera Melinda; Bodai, Tamas; Lucarini, Valerio


    Extreme events statistics provides a theoretical framework to analyze and predict extreme events based on the convergence of the distribution of the extremes to some limiting distribution. In this work we analyze the convergence of the distribution of extreme events to the Generalized Extreme Value (GEV) distribution and to the Generalized Pareto Distribution (GPD), using a two-layer quasi-geostrophic atmospheric model, and compare our results with theoretical findings from the field of extreme value theory for dynamical systems. We study the behavior of the GEV shape parameter by increasing the block size and of the GPD shape parameter by increasing the threshold, and compare the inferred parameters with a theoretical shape parameter that depends only on the geometrical properties of the attractor. The main objective is to find out whether this theoretical shape parameter can be used to evaluate extreme event analysis based on model output. For this, we perform very long simulations. We run our system with two different levels of forcing determined by two different meridional temperature gradients, one inducing a medium level of chaos and the other one a high level of chaos. We analyze in both cases extremes of energy variables.

  17. Deposition, Heat Treatment And Characterization of Two Layer Bioactive Coatings on Cylindrical PEEK. (United States)

    Durham, John W; Rabiei, Afsaneh


    Polyether ether ketone (PEEK) rods were coated via ion beam asssited deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength.

  18. A novel approach to ECG classification based upon two-layered HMMs in body sensor networks. (United States)

    Liang, Wei; Zhang, Yinlong; Tan, Jindong; Li, Yang


    This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient's ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS) filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs) are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC) in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN) platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.

  19. Dynamics and flow-coupling in two-layer turbulent thermal convection

    CERN Document Server

    Xie, Yi-Chao


    We present an experimental investigation of the dynamics and flow-coupling of convective turbulent flows in a cylindrical Rayleigh-Benard convection cell with two immiscible fluids, water and fluorinert FC-77 electronic liquid (FC77). It is found that one large-scale circulation (LSC) roll exists in each of the fluid layers, and that their circulation planes have two preferred azimuthal orientations separated by $\\sim\\pi$. A surprising finding of the study is that cessations/reversals of the LSC in FC77 of the two-layer system occur much more frequently than they do in single-layer turbulent RBC, and that a cessation is most likely to result in a flow reversal of the LSC, which is in sharp contrast with the uniform distribution of the orientational angular change of the LSC before and after cessations in single-layer turbulent RBC. This implies that the dynamics governing cessations and reversals in the two systems are very different. Two coupling modes, thermal coupling (flow directions of the two LSCs are o...

  20. MHD two-layered unsteady fluid flow and heat transfer through a horizontal channel between

    Directory of Open Access Journals (Sweden)

    Raju T. Linga


    Full Text Available An unsteady magnetohydrodynamic (MHD two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a constant uniform pressure gradient in the channel bounded by two parallel insulating plates, when both fluids are considered as electrically conducting, incompressible with variable properties, viz. different viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperatures. The governing partial differential equations are then reduced to the ordinary linear differential equations using two-term series. Closed form solutions for primary and secondary velocity, also temperature distributions are obtained in both the fluid regions of the channel. Profiles of these solutions are plotted to discuss the effects of the flow and heat transfer characteristics, and their dependence on the governing parameters involved, such as the Hartmann number, rotation parameter, ratios of the viscosities, heights, electrical and thermal conductivities

  1. A Two-Layer Method for Sedentary Behaviors Classification Using Smartphone and Bluetooth Beacons. (United States)

    Cerón, Jesús D; López, Diego M; Hofmann, Christian


    Among the factors that outline the health of populations, person's lifestyle is the more important one. This work focuses on the caracterization and prevention of sedentary lifestyles. A sedentary behavior is defined as "any waking behavior characterized by an energy expenditure of 1.5 METs (Metabolic Equivalent) or less while in a sitting or reclining posture". To propose a method for sedentary behaviors classification using a smartphone and Bluetooth beacons considering different types of classification models: personal, hybrid or impersonal. Following the CRISP-DM methodology, a method based on a two-layer approach for the classification of sedentary behaviors is proposed. Using data collected from a smartphones' accelerometer, gyroscope and barometer; the first layer classifies between performing a sedentary behavior and not. The second layer of the method classifies the specific sedentary activity performed using only the smartphone's accelerometer and barometer data, but adding indoor location data, using Bluetooth Low Energy (BLE) beacons. To improve the precision of the classification, both layers implemented the Random Forest algorithm and the personal model. This study presents the first available method for the automatic classification of specific sedentary behaviors. The layered classification approach has the potential to improve processing, memory and energy consumption of mobile devices and wearables used.

  2. Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence

    CERN Document Server

    Farhat, Aseel; Titi, Edriss S; Ziane, Mohammed


    We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integra...

  3. A two-layer $\\alpha\\omega$ dynamo model, and its implications for 1-D dynamos

    CERN Document Server

    Roald, C B


    I will discuss an attempt at representing an interface dynamo in a simplified, essentially 1D framework. The operation of the dynamo is broken up into two 1D layers, one containing the $\\alpha$ effect and the other containing the $\\omega$ effect, and these two layers are allowed to communicate with each other by the simplest possible representation of diffusion, an analogue of Newton's law of cooling. Dynamical back-reaction of the magnetic field on them with diagrams I computed for a comparable purely 1D model. The bifurcation structure shows remarkable similarity, but a couple of subtle changes imply dramatically different physical behaviour for the model. In particular, the solar-like dynamo mode found in the 1-layer model is not stable in the 2-layer version; instead there is an (apparent) homoclinic bifurcation and a sequence of periodic, quasiperiodic, and chaotic modes. I argue that the fragility of these models makes them effectively useless as predictors or interpreters of more complex dynamos.

  4. Two-Layer Linear MPC Approach Aimed at Walking Beam Billets Reheating Furnace Optimization

    Directory of Open Access Journals (Sweden)

    Silvia Maria Zanoli


    Full Text Available In this paper, the problem of the control and optimization of a walking beam billets reheating furnace located in an Italian steel plant is analyzed. An ad hoc Advanced Process Control framework has been developed, based on a two-layer linear Model Predictive Control architecture. This control block optimizes the steady and transient states of the considered process. Two main problems have been addressed. First, in order to manage all process conditions, a tailored module defines the process variables set to be included in the control problem. In particular, a unified approach for the selection on the control inputs to be used for control objectives related to the process outputs is guaranteed. The impact of the proposed method on the controller formulation is also detailed. Second, an innovative mathematical approach for stoichiometric ratios constraints handling has been proposed, together with their introduction in the controller optimization problems. The designed control system has been installed on a real plant, replacing operators’ mental model in the conduction of local PID controllers. After two years from the first startup, a strong energy efficiency improvement has been observed.

  5. A global-scale two-layer transient groundwater model: Development and application to groundwater depletion (United States)

    de Graaf, Inge E. M.; van Beek, Rens L. P. H.; Gleeson, Tom; Moosdorf, Nils; Schmitz, Oliver; Sutanudjaja, Edwin H.; Bierkens, Marc F. P.


    Groundwater is the world's largest accessible source of freshwater to satisfy human water needs. Moreover, groundwater buffers variable precipitation rates over time, thereby effectively sustaining river flows in times of droughts and evaporation in areas with shallow water tables. In this study, building on previous work, we simulate groundwater head fluctuations and groundwater storage changes in both confined and unconfined aquifer systems using a global-scale high-resolution (5‧) groundwater model by deriving new estimates of the distribution and thickness of confining layers. Inclusion of confined aquifer systems (estimated 6-20% of the total aquifer area) improves estimates of timing and amplitude of groundwater head fluctuations and changes groundwater flow paths and groundwater-surface water interaction rates. Groundwater flow paths within confining layers are shorter than paths in the underlying aquifer, while flows within the confined aquifer can get disconnected from the local drainage system due to the low conductivity of the confining layer. Lateral groundwater flows between basins are significant in the model, especially for areas with (partially) confined aquifers were long flow paths crossing catchment boundaries are simulated, thereby supporting water budgets of neighboring catchments or aquifer systems. The developed two-layer transient groundwater model is used to identify hot-spots of groundwater depletion. Global groundwater depletion is estimated as 7013 km3 (137 km3y-1) over 1960-2010, which is consistent with estimates of previous studies.

  6. A Novel Approach to ECG Classification Based upon Two-Layered HMMs in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Wei Liang


    Full Text Available This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient’s ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.

  7. A two-layer recurrent neural network for nonsmooth convex optimization problems. (United States)

    Qin, Sitian; Xue, Xiaoping


    In this paper, a two-layer recurrent neural network is proposed to solve the nonsmooth convex optimization problem subject to convex inequality and linear equality constraints. Compared with existing neural network models, the proposed neural network has a low model complexity and avoids penalty parameters. It is proved that from any initial point, the state of the proposed neural network reaches the equality feasible region in finite time and stays there thereafter. Moreover, the state is unique if the initial point lies in the equality feasible region. The equilibrium point set of the proposed neural network is proved to be equivalent to the Karush-Kuhn-Tucker optimality set of the original optimization problem. It is further proved that the equilibrium point of the proposed neural network is stable in the sense of Lyapunov. Moreover, from any initial point, the state is proved to be convergent to an equilibrium point of the proposed neural network. Finally, as applications, the proposed neural network is used to solve nonlinear convex programming with linear constraints and L1 -norm minimization problems.

  8. Convergence of Extreme Value Statistics in a Two-Layer Quasi-Geostrophic Atmospheric Model

    Directory of Open Access Journals (Sweden)

    Vera Melinda Gálfi


    Full Text Available We search for the signature of universal properties of extreme events, theoretically predicted for Axiom A flows, in a chaotic and high-dimensional dynamical system. We study the convergence of GEV (Generalized Extreme Value and GP (Generalized Pareto shape parameter estimates to the theoretical value, which is expressed in terms of the partial information dimensions of the attractor. We consider a two-layer quasi-geostrophic atmospheric model of the mid-latitudes, adopt two levels of forcing, and analyse the extremes of different types of physical observables (local energy, zonally averaged energy, and globally averaged energy. We find good agreement in the shape parameter estimates with the theory only in the case of more intense forcing, corresponding to a strong chaotic behaviour, for some observables (the local energy at every latitude. Due to the limited (though very large data size and to the presence of serial correlations, it is difficult to obtain robust statistics of extremes in the case of the other observables. In the case of weak forcing, which leads to weaker chaotic conditions with regime behaviour, we find, unsurprisingly, worse agreement with the theory developed for Axiom A flows.

  9. Critical properties of XY model on two-layer Villain-ferromagnetic lattice

    Institute of Scientific and Technical Information of China (English)

    Wang Yi; R. Quartu; Liu Xiao-Yan; Han Ru-Qi; Horiguchi Tsuyoshi


    We investigate phase transitions of the XY model on a two-layer square lattice which consists of a Villain plane(J) and a ferromagnetic plane (I), using Monte Carlo simulations and a histogram method. Depending on the values of interaction parameters (I, J), the system presents three phases: namely, a Kosterlitz-Thouless (KT) phase in which the two planes are critical for I predominant over J, a chiral phase in which the two planes have a chiral order for J predominant over I and a new phase in which only the Villain plane has a chiral order and the ferromagnetic plane is paramagnetic with a small value of chirality. We clarify the nature of phase transitions by using a finite size scaling method. We find three different kinds of transitions according to the values of (I, J): the KT transition, the Ising transition and an XY-Ising transition with v = 0.849(3). It turns out that the Ising or XY-Ising transition is associated with the disappearance of the chiral order in the Villain plane.

  10. Powerful Amplification Cascades of FRET-Based Two-Layer Nonenzymatic Nucleic Acid Circuits. (United States)

    Quan, Ke; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Ying, Le; Wang, He; Xie, Nuli; Ou, Min; Wang, Kemin


    Nucleic acid circuits have played important roles in biological engineering and have increasingly attracted researchers' attention. They are primarily based on nucleic acid hybridizations and strand displacement reactions between nucleic acid probes of different lengths. Signal amplification schemes that do not rely on protein enzyme show great potential in analytical applications. While the single amplification circuit often achieves linear amplification that may not meet the need for detection of target in a very small amount, it is very necessary to construct cascade circuits that allow for larger amplification of inputs. Herein, we have successfully engineered powerful amplification cascades of FRET-based two-layer nonenzymatic nucleic acid circuits, in which the outputs of catalyzed hairpin assembly (CHA) activate hybridization chain reactions (HCR) circuits to induce repeated hybridization, allowing real-time monitoring of self-assembly process by FRET signal. The cascades can yield 50000-fold signal amplification with the help of the well-designed and high-quality nucleic acid circuit amplifiers. Subsequently, with coupling of structure-switching aptamer, as low as 200 pM adenosine is detected in buffer, as well as in human serum. To our knowledge, we have for the first time realized real-time monitoring adaptation of HCR to CHA circuits and achieved amplified detection of nucleic acids and small molecules with relatively high sensitivity.

  11. Synthesis of a mathematical model of the UO/sub 2/(NO/sub 3/)/sub 2/-HNO/sub 3/-H/sub 2/O-TBP system from mathematical models of constituent subsystems

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaeva, L.S.; Prikhod' ko, N.V.; Evseev, A.M.; Pozen, A.M.; Kolychev, A.E.; Gontar' , V.G. (Moskovskij Gosudarstvennyj Univ. (USSR))


    A mathematical model of the UO/sub 2/(NO/sub 3/)/sub 2/-HNO/sub 3/-H/sub 2/O-TBP system is synthesized from the obtained earlier mathematical models of its constituent subsystems: HNO/sub 3/-H/sub 2/O-TBP and UO/sub 2/(NO/sub 3/)/sub 2/-TBP. The model has been checked for consistency with the literature data. The synthesized model predicts extraction of nitric acid and uranyl microamounts into the organic phase with a 15% error.

  12. Gamma-radiolysis of TBP and DBPA in the presence of HNO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, I.A.; Kermanova, N.V.; Vladimirova, M.V.


    The authors show that DBPA, MBPA, H/sub 3/PO/sub 4/, polymer, nitration and oxidation products, hydrogen, and gaseous products (methane, ethane, etc.) are formed. When oxygen or air is bubbled through the two-phase system, the rate of formation of acidic radiolysis products is constant over gamma irradiation doses and is greater than the rate of formation in oxygen-deficient systems. It has been shown that /sup G/ DBPA and /sup G/ MBPA and the equilibrium concentrations of DBPA are greater. Other conditions being equal, the greater is the concentration of metal ions (Pu/sup 4 +/, UO/sup 2 +//sub 2/) in the extractant.

  13. Dependences of optical properties of spherical two-layered nanoparticles on parameters of gold core and material shell (United States)

    Pustovalov, V. K.; Astafyeva, L. G.; Zharov, V. P.


    Modeling of nonlinear dependences of optical properties of spherical two-layered gold core and some material shell nanoparticles (NPs) placed in water on parameters of core and shell was carried out on the basis of the extended Mie theory. Efficiency cross-sections of absorption, scattering and extinction of radiation with wavelength 532 nm by core-shell NPs in the ranges of core radii r00=5-40 nm and of relative NP radii r1/r00=1-8 were calculated (r1-radius of two-layered nanoparticle). Shell materials were used with optical indexes in the ranges of refraction n1=0.2-1.5 and absorption k1=0-3.5 for the presentation of optical properties of wide classes of shell materials (including dielectrics, metals, polymers, vapor shell around gold core). Results show nonlinear dependences of optical properties of two-layered NPs on optical indexes of shell material, core r00 and relative NP r1/r00 radii. Regions with sharp decrease and increase of absorption, scattering and extinction efficiency cross-sections with changing of core and shell parameters were investigated. These dependences should be taken into account for applications of two-layered NPs in laser nanomedicine and optical diagnostics of tissues. The results can be used for experimental investigation of shell formation on NP core and optical determination of geometrical parameters of core and shell of two-layered NPs.


    Institute of Scientific and Technical Information of China (English)


    In this paper, the adaptation process in low latitude atmosphere is discussed by means of a two-layer baroclinic model on the equator β plane, showing that the adaptation process in low latitude is mainly dominated by the internal inertial gravity waves. The initial ageostrophic energy is dispersed by the internal inertial gravity waves, and as a result, the geostrophic motion is obtained in zonal direction while the ageostrophic motion maintains in meridional direction, which can be called semi-geostrophic balance in barotropic model as well as semi-thermal-wind balance in baroclinic model. The vertical motion is determined both by the distribution of the initial vertical motion and that of the initial vertical motion tendency, but it is unrelated to the initial potential vorticity. Finally, the motion tends to be horizontal. The discussion of the physical mechanism of the semi-thermal-wind balance in low latitude atmosphere shows that the achievement of the semi-thermal-wind balance is due to the adjustment between the stream field and the temperature field through the horizontal convergence and divergence which is related to the vertical motion excited by the internal inertial gravity waves. The terminal adaptation state obtained shows that the adaptation direction between the mean temperature field and the shear flow field is determined by the ratio of the scale of the initial ageostrophic disturbance to the scale of one character scale related to the baroclinic Rossby radius of deformation. The shear stream field adapts to the mean temperature field when the ratio is greater than 1, and the mean temperature field adapts to the shear stream field when the ratio is smaller than 1.

  15. Convective instability in a two-layer system of reacting fluids with concentration-dependent diffusion (United States)

    Aitova, E. V.; Bratsun, D. A.; Kostarev, K. G.; Mizev, A. I.; Mosheva, E. A.


    The development of convective instability in a two-layer system of miscible fluids placed in a narrow vertical gap has been studied theoretically and experimentally. The upper and lower layers are formed with aqueous solutions of acid and base, respectively. When the layers are brought into contact, the frontal neutralization reaction begins. We have found experimentally a new type of convective instability, which is characterized by the spatial localization and the periodicity of the structure observed for the first time in the miscible systems. We have tested a number of different acid-base systems and have found a similar patterning there. In our opinion, it may indicate that the discovered effect is of a general nature and should be taken into account in reaction-diffusion-convection problems as another tool with which the reaction can govern the movement of the reacting fluids. We have shown that, at least in one case (aqueous solutions of nitric acid and sodium hydroxide), a new type of instability called as the concentration-dependent diffusion convection is responsible for the onset of the fluid flow. It arises when the diffusion coefficients of species are different and depend on their concentrations. This type of instability can be attributed to a variety of double-diffusion convection. A mathematical model of the new phenomenon has been developed using the system of reaction-diffusion-convection equations written in the Hele-Shaw approximation. It is shown that the instability can be reproduced in the numerical experiment if only one takes into account the concentration dependence of the diffusion coefficients of the reagents. The dynamics of the base state, its linear stability and nonlinear development of the instability are presented. It is also shown that by varying the concentration of acid in the upper layer one can achieve the occurrence of chemo-convective solitary cell in the bulk of an almost immobile fluid. Good agreement between the

  16. Global chaotization of fluid particle trajectories in a sheared two-layer two-vortex flow

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhov, Evgeny A., E-mail: [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Koshel, Konstantin V., E-mail: [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Far Eastern Federal University, 8, Sukhanova Street, Vladivostok 690950 (Russian Federation)


    In a two-layer quasi-geostrophic approximation, we study the irregular dynamics of fluid particles arising due to two interacting point vortices embedded in a deformation flow consisting of shear and rotational components. The two vortices are arranged within the bottom layer, but an emphasis is on the upper-layer fluid particle motion. Vortices moving in one layer induce stirring of passive scalars in the other layer. This is of interest since point vortices induce singular velocity fields in the layer they belong to; however, in the other layer, they induce regular velocity fields that generally result in a change in passive particle stirring. If the vortices are located at stagnation points, there are three different types of the fluid flow. We examine how properties of each flow configuration are modified if the vortices are displaced from the stagnation points and thus circulate in the immediate vicinity of these points. To that end, an analysis of the steady-state configurations is presented with an emphasis on the frequencies of fluid particle oscillations about the elliptic stagnation points. Asymptotic relations for the vortex and fluid particle zero–oscillation frequencies are derived in the vicinity of the corresponding elliptic points. By comparing the frequencies of fluid particles with the ones of the vortices, relations between the parameters that lead to enhanced stirring of fluid particles are established. It is also demonstrated that, if the central critical point is elliptic, then the fluid particle trajectories in its immediate vicinity are mostly stable making it harder for the vortex perturbation to induce stirring. Change in the type of the central point to a hyperbolic one enhances drastically the size of the chaotic dynamics region. Conditions on the type of the central critical point also ensue from the derived asymptotic relations.

  17. Interaction of plutonium(iv) with mono-n-butylphosphoric acid in nitric acid solutions and in the system 30% TBP + n-dodecane

    Energy Technology Data Exchange (ETDEWEB)

    Rovnyi, S.I.; Boikova, I.A.; Fedoseev, D.A.; Goncharuk, L.V.; Milovanova, A.S.; Sokhina, L.P.


    The methods of elementary and spectrophotometric analysis at the temperature 22 + or - 2 degrees C were used to investigate the interaction of mono-n-butylphosphoric acid (MBPA, H/sub 2/B) with Pu(IV) in nitric acid solutions and in the system 30% TBP + n-dodecane. The conditions of formatin, solubility, and composition of precipitates of MBPA with Pu(OV) were investigated; the effective stability constants K of complexes of Pu(IV) with MBPA of various compositions were determined. The results of the studies are discussed in comparison with the interaction of Zn(IV) with MBPA in nitric acid solutions and in the system 30% TBP + n-dodecane.

  18. Extracción de cromo con disolventes orgánicos. II parte. Extracción con TBP y con Primene 81R

    Directory of Open Access Journals (Sweden)

    Juan, D.


    Full Text Available The use of a neutral reactive (TBP and an alkalyne one (Primene 81R in order to carry out the extraction of chromium from aqueous solutions was studied. The following systems were tested: Cr(VI/TBP, Cr(III/Primene 81R, Cr(VI/Primene 81R. In the same way the stripping of both systems were studied. TBP can easily extract Cr(VI using pure TBP as organic phase and an aqueous phase with a concentration of sulphuric acid between 0.5 and 2 N. The kinetics of the process is very fast. NaOH solutions were used for stripping, reaching maximum yields with IN NaOH solutions. Primene 81R can extract not only Cr(III but also Cr(VI. Extraction of Cr(III must be made at values of pH around 6; this value has to be reached by addition of extraction agent. Extraction of Cr(VI must be made at values of pH between 3 and 5. Extraction kinetics of Cr(III and Cr(VI are both fast. In order to carry out the reextraction, NaOH solutions can be used. Cr(III is recovered as a chromium hydroxide precipitate if final pH is alkalyne; solutions of NaOH with a concentration equal or higher than 4N must be used for the stripping of Cr(VI, and the solution obtained contains chromium as Cr(III and Cr(VI.

    Se estudia el empleo de un reactivo de carácter neutro (TBP y otro de carácter básico (Primene 81R para llevar a cabo la extracción del cromo presente en disoluciones acuosas. Los sistemas investigados han sido el Cr(VI/TBP, el Cr(III/Primene 81R y el Cr(VI/Primene 81R. Asimismo, se abordan los procesos de reextracción en dichos sistemas. El TBP ha demostrado su capacidad para extraer el Cr(VI, debiendo estar constituida la fase orgánica por TBP puro y la fase acuosa poseer una concentración en ácido sulfúrico entre 0,5 y 2 N. La cinética del proceso es rápida. Se han empleado disoluciones de NaOH para proceder a la reextracción, alcanzándose el máximo rendimiento con disoluciones de NaOH 1N. El Primene 81R puede extraer tanto al Cr(III como al Cr(VI. La

  19. Dipole Strength Calculation Based on Two-Level System Approximation to Study Q/B-Band Intensity Ratio of ZnTBP in Solvent (United States)

    Rusydi, Febdian; Shukri, Ganes; Saputro, Adithya G.; Agusta, Mohammad K.; Dipojono, Hermawan K.; Suprijadi, Suprijadi


    We study the Q/B-band dipole strength of zinc tetrabenzoporphyrin (ZnTBP) using density functional theory (DFT) in various solvents. The solvents are modeled using the polarized continuum model (PCM). The dipole strength calculations are approached by a two-level system, where the Q-band is described by the HOMO → LUMO electronic transition and the B-band by the HOMO-1 → LUMO electronic transition. We compare the results with the experimental data of the Q/B-band intensity ratio. We also perform time-dependent DFT coupled with PCM to calculate the Q/B-band oscillator strength ratio of ZnTBP. The results of both methods show a general trend with respect to the experimental Q/B-band intensity ratio in solvents, except for the calculation in the water solvent. Even so, the approximation is a good starting point for studying the UV-vis spectrum based on DFT study alone.

  20. An operational two-layer remote sensing model to estimate surface flux in regional scale: Physical background

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Renhua; SUN; Xiaomin; WANG; Weimin; XU; Jinping; ZH


    Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.

  1. New Data on Joint Extraction of Nitric Acid, Uranium(VI) and Tetravalent Elements by Diluted TBP and New Approach to Modeling of their Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Zilberman, B.Ya.; Fedorov, Yu.S.; Puzikov, E.A.; Blazheva, I.V. [RPA ' V.G. Khlopin Radium Institute' , 28, 2nd Murinskiy av., Saint-Petersburg, 194021 (Russian Federation)


    HNO{sub 3} and U(IV) extraction by diluted TBP (tributyl phosphate) appeared significantly higher than believed earlier, requiring correction of mathematical model for extraction of all the species. The proposed model of HNO{sub 3} extraction includes its dissolving in the extracted water, as well as its abduction to UO{sub 2}(NO{sub 3}){sub 2}(TBP){sub 2}. Extraction of U(VI) and tetravalent elements is considered as reaction of their hydrated or partially hydrolyzed forms, the latter could be extracted themselves or as neutral forms with water liberation. The equation of element chemical reaction for modeling is determined by the slope of the linear part of the S-shaped curve representing D/S{sup 2} function as a plot of HNO{sub 3} concentration, where D is a distribution coefficient of the micro-component and S is a TBP concentration free of HNO{sub 3}. The description of tetravalent element extraction in U(VI) presence needs the assumption of cation-cation interaction of element hydrolyzed forms with U(VI) in aqueous phase. Zr distribution is affected by micellar effects. (authors)

  2. Electromagnetic fields due to a horizontal electric dipole antenna laid on the surface of a two-layer medium (United States)

    Tsang, L.; Kong, J. A.


    With applications to geophysical subsurface probings, electromagnetic fields due to a horizontal electric dipole laid on the surface of a two-layer medium are solved by a combination of analytic and numerical methods. Interference patterns are calculated for various layer thickness. The results are interpreted in terms of normal modes, and the accuracies of the methods are discussed.

  3. [Two-layer adhesive film Diplen-denta C--a new compound containing polymer base and active component Solcoseryl]. (United States)

    Abakarova, D S


    Characteristics of the main components of a new effective long-lasting dosage form--biopolymer two-layer adhesive solcoseryl containing film Diplen-denta C--are presented. It has a potent wound-healing action on oral mucosa, retains therapeutic properties during long time, is self dissolving and can be easily fixed on oral mucous membrane.

  4. Screen-Capturing System with Two-Layer Display for PowerPoint Presentation to Enhance Classroom Education (United States)

    Lai, Yen-Shou; Tsai, Hung-Hsu; Yu, Pao-Ta


    This paper proposes a new presentation system integrating a Microsoft PowerPoint presentation in a two-layer method, called the TL system, to promote learning in a physical classroom. With the TL system, teachers can readily control hints or annotations as a way of making them visible or invisible to students so as to reduce information load. In…

  5. Hamiltonian Particle-Mesh Method for Two-Layer Shallow-Water Equations Subject to the Rigid-Lid Approximation

    NARCIS (Netherlands)

    Cotter, C.J.; Frank, J.E.; Reich, S.


    We develop a particle-mesh method for two-layer shallow-water equations subject to the rigid-lid approximation. The method is based on the recently proposed Hamiltonian particle-mesh (HPM) method and the interpretation of the rigid-lid approximation as a set of holonomic constraints. The suggested s

  6. ATLAS-TPX: a two-layer pixel detector setup for neutron detection and radiation field characterization (United States)

    Bergmann, B.; Caicedo, I.; Leroy, C.; Pospisil, S.; Vykydal, Z.


    A two-layer pixel detector setup (ATLAS-TPX), designed for thermal and fast neutron detection and radiation field characterization is presented. It consists of two segmented silicon detectors (256 × 256 pixels, pixel pitch 55 μm, thicknesses 300 μm and 500 μm) facing each other. To enhance the neutron detection efficiency a set of converter layers is inserted in between these detectors. The pixelation and the two-layer design allow a discrimination of neutrons against γs by pattern recognition and against charged particles by using the coincidence and anticoincidence information. The neutron conversion and detection efficiencies are measured in a thermal neutron field and fast neutron fields with energies up to 600 MeV. A Geant4 simulation model is presented, which is validated against the measured detector responses. The reliability of the coincidence and anticoincidence technique is demonstrated and possible applications of the detector setup are briefly outlined.

  7. Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka


    Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

  8. Tensile Properties with or without Heat Dispersion of Automotive Needlepunched Carpets Made up of Two Layers of Different Materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunqing; GUO Zhiying; DONG Xianghuai; LI Dequn


    Tensile properties of automotive needlepunched carpets made up of two layers of different materials (a fabric layer and a foam layer) in their thermoforming temperatures ranges with or without heat dispersion were discussed. Effects of forming temperature, extensile speed and fiber orientation on the tensile properties were studied based on an orthogonal experiment design. The experimental results show that automotive carpets are rate-dependent anisotropic materials and more strongly depend on forming temperature than the extensile speed and fiber orientation. Furthermore,contributions of the fabric layer and the foam layer to the overall tensile performance were investigated by comparing the tensile results of single fabric layer with those of the overall carpet. Both the fabric layer and the foam layer show positive effects on the overall tensile strength which is the combination of the two layers' tensile strength and independent of temperature, extensile speed and fiber orientation.On the other hand, their influences on the overall deformation are relatively complicated.

  9. Determining particle size distribution and refractive index in a two-layer tissue phantom by linearly polarized light

    Institute of Scientific and Technical Information of China (English)

    Yong Deng; Qiang Lu; Qingming Luo


    We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer in a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scattering components in the returned signal. The theoretical model based on Mie theory is presented and a nonlinear inversion method - floating genetic algorithm - is applied to inverting the azimuth dependence of component of polarization light backscattered. The experiment results demonstrate that the size distribution and refractive index of the scatters of the top layer can be determined by measuring and analyzing the differential signal of the parallel and perpendicular components from a two-layer tissue phantom. The method implies to detect precancerous changes in human epithelial tissue.

  10. Two-layer critical dimensions and overlay process window characterization and improvement in full-chip computational lithography (United States)

    Sturtevant, John L.; Liubich, Vlad; Gupta, Rachit


    Edge placement error (EPE) was a term initially introduced to describe the difference between predicted pattern contour edge and the design target for a single design layer. Strictly speaking, this quantity is not directly measurable in the fab. What is of vital importance is the relative edge placement errors between different design layers, and in the era of multipatterning, the different constituent mask sublayers for a single design layer. The critical dimensions (CD) and overlay between two layers can be measured in the fab, and there has always been a strong emphasis on control of overlay between design layers. The progress in this realm has been remarkable, accelerated in part at least by the proliferation of multipatterning, which reduces the available overlay budget by introducing a coupling of overlay and CD errors for the target layer. Computational lithography makes possible the full-chip assessment of two-layer edge to edge distances and two-layer contact overlap area. We will investigate examples of via-metal model-based analysis of CD and overlay errors. We will investigate both single patterning and double patterning. For single patterning, we show the advantage of contour-to-contour simulation over contour to target simulation, and how the addition of aberrations in the optical models can provide a more realistic CD-overlay process window (PW) for edge placement errors. For double patterning, the interaction of 4-layer CD and overlay errors is very complex, but we illustrate that not only can full-chip verification identify potential two-layer hotspots, the optical proximity correction engine can act to mitigate such hotspots and enlarge the joint CD-overlay PW.

  11. Dynamics of the outflow and its effect on the hydraulics of two-layer exchange flows in a channel

    Institute of Scientific and Technical Information of China (English)


    This paper reports that an experimental study is conducted to examine the dynamics of the outflow in two-layer exchange flows in a channel connecting between two water bodies with a small density difference. The experiments reveal the generation of Kelvin-Helmholtz (KH) instabilities within the hydraulically sub-critical flow region of the channel. During maximal exchange, those KH instabilities develops into large-amplitude KH waves as they escape the channel exit into the reservoir. The propagation speed ...

  12. Two-Layer Microstructures Fabricated by One-Step Anisotropic Wet Etching of Si in KOH Solution

    Directory of Open Access Journals (Sweden)

    Han Lu


    Full Text Available Anisotropic etching of silicon in potassium hydroxide (KOH is an important technology in micromachining. The residue deposition from KOH etching of Si is typically regarded as a disadvantage of this technology. In this report, we make use of this residue as a second masking layer to fabricate two-layer complex structures. Square patterns with size in the range of 15–150 μm and gap distance of 5 μm have been designed and tested. The residue masking layer appears when the substrate is over-etched in hydrofluoric acid (HF solution over a threshold. The two-layer structures of micropyramids surrounded by wall-like structures are obtained according to the two different masking layers of SiO2 and residue. The residue masking layer is stable and can survive over KOH etching for long time to achieve deep Si etching. The process parameters of etchant concentration, temperature, etching time and pattern size have been investigated. With well-controlled two-layer structures, useful structures could be designed for applications in plasmonic and microfluidic devices in the future.

  13. Laboratory Research of the Two-Layer Liquid Dynamics at the Wind Surge in a Strait Canal

    Directory of Open Access Journals (Sweden)

    S.F. Dotsenko


    Full Text Available The results of laboratory experiments in a straight aerohydrocanal of the rectangular cross-section filled with the two-layer (fresh-salty liquid are represented. The disturbance generator is the air flow directed to the area above the canal. The cases of the two-layer liquid dynamics in the canal with the horizontal flat bottom and in the presence of the bottom obstacle of finite width are considered. It is shown that during the surge in the straight canal, one of the possible exchange mechanisms on the boundary of fresh and salty layers may consist in the salt water emissions (resulted from the Kelvin-Helmholtz instability to the upper freshwater layer. The subsequent eviction can possibly be accompanied by occurrence of undulations at the interface. Besides, the evictions can be followed by formation of the oscillating layer, i.e. the layer with maximum density gradient the oscillations of which propagate to the overlying layers. Presence of the bottom obstacle complicates the structure of the two-layer liquid motions. In particular, it results in emergence of the mixed layers and transformation of the flow behind the obstacle into a turbulent one, formation of the wave-like disturbances over the obstacle, sharp change of the interface position and occurrence of large-scale vortices with the horizontal axes. It is revealed that the maximum peak of the flow velocity horizontal component is shifted upstream from the obstacle.

  14. Distributed Processing System for Restoration of Electric Power Distribution Network Using Two-Layered Contract Net Protocol (United States)

    Kodama, Yu; Hamagami, Tomoki

    Distributed processing system for restoration of electric power distribution network using two-layered CNP is proposed. The goal of this study is to develop the restoration system which adjusts to the future power network with distributed generators. The state of the art of this study is that the two-layered CNP is applied for the distributed computing environment in practical use. The two-layered CNP has two classes of agents, named field agent and operating agent in the network. In order to avoid conflicts of tasks, operating agent controls privilege for managers to send the task announcement messages in CNP. This technique realizes the coordination between agents which work asynchronously in parallel with others. Moreover, this study implements the distributed processing system using a de-fact standard multi-agent framework, JADE(Java Agent DEvelopment framework). This study conducts the simulation experiments of power distribution network restoration and compares the proposed system with the previous system. We confirmed the results show effectiveness of the proposed system.

  15. Optical characterization of two-layered turbid media for non-invasive, absolute oximetry in cerebral and extracerebral tissue.

    Directory of Open Access Journals (Sweden)

    Bertan Hallacoglu

    Full Text Available We introduce a multi-distance, frequency-domain, near-infrared spectroscopy (NIRS method to measure the optical coefficients of two-layered media and the thickness of the top layer from diffuse reflectance measurements. This method features a direct solution based on diffusion theory and an inversion procedure based on the Levenberg-Marquardt algorithm. We have validated our method through Monte Carlo simulations, experiments on tissue-like phantoms, and measurements on the forehead of three human subjects. The Monte Carlo simulations and phantom measurements have shown that, in ideal two-layered samples, our method accurately recovers the top layer thickness (L, the absorption coefficient (µ a and the reduced scattering coefficient (µ' s of both layers with deviations that are typically less than 10% for all parameters. Our method is aimed at absolute measurements of hemoglobin concentration and saturation in cerebral and extracerebral tissue of adult human subjects, where the top layer (layer 1 represents extracerebral tissue (scalp, skull, dura mater, subarachnoid space, etc. and the bottom layer (layer 2 represents cerebral tissue. Human subject measurements have shown a significantly greater total hemoglobin concentration in cerebral tissue (82±14 µM with respect to extracerebral tissue (30±7 µM. By contrast, there was no significant difference between the hemoglobin saturation measured in cerebral tissue (56%±10% and extracerebral tissue (62%±6%. To our knowledge, this is the first time that an inversion procedure in the frequency domain with six unknown parameters with no other prior knowledge is used for the retrieval of the optical coefficients and top layer thickness with high accuracy on two-layered media. Our absolute measurements of cerebral hemoglobin concentration and saturation are based on the discrimination of extracerebral and cerebral tissue layers, and they can enhance the impact of NIRS for cerebral hemodynamics and

  16. Radiative transfer theory for passive microwave remote sensing of a two-layer random medium with cylindrical structures (United States)

    Chuang, S. L.; Kong, J. A.; Tsang, L.


    A model of the vegetation layer as a two-layer random medium with a small correlation length l sub rho in the horizontal direction, and a large correlation length l sub z in the vertical direction, is presented for fields with cylindrical structures. As l sub z approaches infinity, closed form solutions are derived for the brightness temperatures; the kernels in the scattering terms of the radiative transfer equations result in delta functions showing that forward scattering is dominant over all other directions. The results are compared with the Gaussian quadrature method data for numerical solution of the radiative transfer equations.


    Institute of Scientific and Technical Information of China (English)

    ZHU Wei; YOU Yun-xiang; MIAO Guo-ping; ZHAO Feng; ZHANG Jun


    This paper is concerned with the waves generated by a 3-D body advancing beneath the free surface with constant speed in a two-layer fluid of finite depth. By applying Green's theorem, a layered integral equation system based on the Rankine source for the perturbed velocity potential generated by the moving body was derived with the potential flow theory. A four-node isoparametric element method was used to treat with the solution of the layered integral equation system. The surface and interface waves generated by a moving ball were calculated numerically. The results were compared with the analytical results for a moving source with constant velocity.

  18. Quasi-two-layer finite-volume scheme for modeling shallow water flows with the presence of external forces

    CERN Document Server

    Karelsky, K V; Slavin, A G


    The numerical method for study of hydrodynamic flows over an arbitrary bed profile in the presence of external force is proposed in this paper. This method takes into account the external force effect, it uses the quasi-two-layer model of hydrodynamic flows over a stepwise boundary with consideration of features of the flow near the step. A distinctive feature of the proposed method is the consideration of the properties of the process of the waterfall, namely the fluid flow on the step in which the fluid does not wet part of the vertical wall of the step. The presence of dry zones in the vertical part of the step indicates violation of the conditions of hydrostatic flow. The quasi-two-layer approach allows to determine the size of the dry zone of the vertical component of the step. Consequently it gives an opportunity to figure out the amount of kinetic energy dissipation. There are performed the numerical simulations based on the proposed algorithm of various physical phenomena, such as a breakdown of the r...

  19. Linear and nonlinear properties of reduced two-layer models for non-hydrostatic free-surface flow (United States)

    Bai, Yefei; Cheung, Kwok Fai


    A two-layer model with uniform non-hydrostatic pressure in the bottom produces favorable dispersion properties for coastal wave transformation at the computational requirements of a one-layer model. We derive the nonlinear governing equations and the corresponding dispersion relation, shoaling gradient, and super- and sub-harmonics to understand the theoretical performance of this reduced model. With the layer interface near the bottom, the dispersion relation shows an extended applicable range into deeper water at the expense of a slight overestimation of the celerity in intermediate water depth. The shoaling gradient rapidly converges to the exact solution in the shallow and intermediate depth range. These complementary characteristics allow identification of an optimal interface position for both linear wave properties. The resulting model exhibits good nonlinear performance in shallow and intermediate water depth and produces super- and sub-harmonics comparable to a two-layer model. Numerical tests involving standing waves show the reduced model has smaller discretization errors in the dispersion relation comparing to a one-layer model. Case studies of regular wave transformation over a submerged bar and a uniform slope provide comparison with laboratory data and demonstrate the linear and nonlinear properties derived from the governing equations. The good shoaling and nonlinear properties give rise to accurate waveforms in both cases, while dispersion errors from the governing equations and numerical schemes accumulate over time leading to phase shifts of the modeled waves.

  20. Acoustic scattering by a two-layer cylindrical tube immersed in a fluid medium: Existence of a pseudo wave. (United States)

    Elhanaoui, Abdelkader; Aassif, Elhoucein; Maze, Gérard; Décultot, Dominique


    The present paper studies the acoustic signal backscattered by an air-filled copper–solid polymer two-layer cylindrical tube immersed in water. The work is done from the calculation of the backscattered pressure, an inverse Fourier Transform, which allows us to obtain an impulse signal. Smoothed pseudo Wigner–Ville and Concentrated spectrogram representations have been chosen to analyze the scattering phenomenon. For reduced frequencies ranging from 0.1 to 200, the resonance trajectories and time–frequency images have shown the presence of the guided waves. The bifurcation of the A0 wave into the A0(-) and the A0(+) waves has also been observed. The authors provide the phase and the group velocities of guided waves and investigate the differences between curves. The findings are then compared with those obtained for the copper and the solid polymer one-layer cylindrical tubes. Group velocity values have also been extracted from smoothed pseudo Wigner–Ville and Concentrated spectrogram time–frequency images. A good agreement with the theory has, therefore, been observed. The study of acoustic backscattering by a copper–solid polymer two-layer tube has revealed the interaction and the coupling of guided waves, specially the presence of a pseudo A1 wave; which is a very interesting, remarkable phenomenon.

  1. Modeling of PZT-induced Lamb wave propagation in structures by using a novel two-layer spectral finite element (United States)

    Liu, Xiaotong; Zhou, Li; Ouyang, Qinghua


    This paper presents a novel two-layer spectral finite element model, consisting of PZT wafer and host structure, to simulate PZT-induced Lamb wave propagation in beam-like and plate-like structures. Based on the idea of equal displacement on the interface between PZT wafer and host structure, the one-dimensional spectral beam element of PZT-host beam and two-dimensional spectral plate element of PZT-host plate are considered as one hybrid element, respectively. A novel approach is proposed by taking the coupling effect of piezoelectric transducers in the thickness direction into account. The dynamic equation of the two-layer spectral element is derived from Hamilton's principle. Validity of the developed spectral finite element is verified through numerical simulation. The result indicates that, compared with the conventional finite element method (FEM) based on elasticity, the proposed spectral finite element is proved to have a high accuracy in modeling Lamb wave propagation, meanwhile, significantly improve the calculation efficiency.

  2. A Numerical Study on Water Waves Generated by A Submerged Moving Body in A Two-Layer Fluid System

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-Zhen; NG Chiu-On; ZHANG Dao-Hua


    This is a numerical study on the time development of surface waves generated by a submerged body moving steadily in a two-layer fluid system, in which a layer of water is underlain by a layer of viscous mud. The fully nonlinear Navier-Stokes equations are solved on FLUENT with the Volume-of-Fluid (VOF) multiphase scheme in order to simulate the free surface waves as well as the water-mud interface waves as functions of time. The numerical model is validated by mimick-ing a reported experiment in a one-layer system before it is applied to a two-layer system, it is found that the presence of bottom mud in a water layer can lead to large viscous damping of the surface waves. For the investigation of the problem systematically, the effects of the Froude number and the mud layer thickness, density and viscosity relative to those of water are evaluated and discussed in detail.

  3. A two-layer structured PbI2 thin film for efficient planar perovskite solar cells (United States)

    Ying, Chao; Shi, Chengwu; Wu, Ni; Zhang, Jincheng; Wang, Mao


    In this paper, a two-layer structured PbI2 thin film was constructed by the spin-coating procedure using a 0.80 M PbI2 solution in DMF and subsequent close-spaced vacuum thermal evaporation using PbI2 powder as a source. The bottom PbI2 thin film was compact with a sheet-like appearance, parallel to the FTO substrate, and can be easily converted to a compact perovskite thin film to suppress the charge recombination of the electrons of the TiO2 conduction band and the holes of the spiro-OMeTAD valence band. The top PbI2 thin film was porous with nano-sheet arrays, perpendicular to the FTO substrate, and can be easily converted to a porous perovskite thin film to improve the hole migration from the perovskite to spiro-OMeTAD and the charge separation at the perovskite/spiro-OMeTAD interface. The planar perovskite solar cells based on the two-layer structured PbI2 thin film exhibited a photoelectric conversion efficiency of 11.64%, along with an open-circuit voltage of 0.90 V, a short-circuit photocurrent density of 19.29 mA cm-2 and a fill factor of 0.67.

  4. Equivalent circuit models of two-layer flexure beams with excitation by temperature, humidity, pressure, piezoelectric or piezomagnetic interactions

    Directory of Open Access Journals (Sweden)

    U. Marschner


    Full Text Available Two-layer flexure beams often serve as basic transducers in actuators and sensors. In this paper a generalized description of their stimuli-influenced mechanical behavior is derived. For small deflection angles this description includes a multi-port circuit or network representation with lumped elements for a beam part of finite length. A number of coupled finite beam parts model the dynamic behavior including the first natural frequencies of the beam. For piezoelectric and piezomagnetic interactions, reversible transducer models are developed. The piezomagnetic two-layer beam model is extended to include solenoid and planar coils. Linear network theory is applied in order to determine network parameters and to simplify the circuit representation. The resulting circuit model is the basis for a fast simulation of the dynamic system behavior with advanced circuit simulators and, thus, the optimization of the system. It is also a useful tool for understanding and explaining this multi-domain system through basic principles of general system theory.

  5. Interaction of water waves with small undulations on a porous bed in a two-layer ice-covered fluid (United States)

    Panda, Srikumar; Martha, S. C.


    The scattering problem involving water waves by small undulation on the porous ocean-bed in a two-layer fluid, is investigated within the framework of the two-dimensional linear water wave theory where the upper layer is covered by a thin uniform sheet of ice modeled as a thin elastic plate. In such a two-layer fluid there exist waves with two different modes, one with a lower wave number propagate along the ice-cover whilst those with a higher wave number propagate along the interface. An incident wave of a particular wave number gets reflected and transmitted over the bottom undulation into waves of both modes. Perturbation analysis in conjunction with the Fourier transform technique is used to derive the first-order corrections of reflection and transmission coefficients for both the modes due to incident waves of two different modes. One special type of bottom topography is considered as an example to evaluate the related coefficients in detail. These coefficients are depicted in graphical forms to demonstrate the transformation of wave energy between the two modes and also to illustrate the effects of the ice sheet and the porosity of the undulating bed.

  6. A constructive algorithm to solve "convex recursive deletion" (CoRD) classification problems via two-layer perceptron networks. (United States)

    Cabrelli, C; Molter, U; Shonkwiler, R


    A sufficient condition that a region be classifiable by a two-layer feedforward neural net (a two-layer perceptron) using threshold activation functions is that either it be a convex polytope or that intersected with the complement of a convex polytope in its interior, or that intersected with the complement of a convex polytope in its interior or ... recursively. These have been called convex recursive deletion (CoRD) regions.We give a simple algorithm for finding the weights and thresholds in both layers for a feedforward net that implements such a region. The results of this work help in understanding the relationship between the decision region of a perceptron and its corresponding geometry in input space. Our construction extends in a simple way to the case that the decision region is the disjoint union of CoRD regions (requiring three layers). Therefore this work also helps in understanding how many neurons are needed in the second layer of a general three-layer network. In the event that the decision region of a network is known and is the union of CoRD regions, our results enable the calculation of the weights and thresholds of the implementing network directly and rapidly without the need for thousands of backpropagation iterations.

  7. Transient flexural-and capillary-gravity waves due to disturbances in two-layer density-stratified fluid

    Institute of Scientific and Technical Information of China (English)

    LU Dong-qiang; SUN Cui-zhi


    Generation of the transient flexural-and capillary-gravity waves by impulsive disturbances in a two-layer fluid is investigated analytically.The upper fluid is covered by a thin elastic plate or by an inertial surface with the capillary effect.The density of each of the two immiscible layers is constant.The fluids are assumed to be inviscid and incompressible and the motion be irrotational.A point force on the surface and simple mass sources in the upper and lower fluid layers are considered.A linear system is established within the framework of potential theory.The integral solutions for the surface and interfacial waves are obtained by means of the Laplace-Fourier transform.A new representation for the dispersion relation of flexural-and capillary-gravity waves in a two-layer fluid is derived.The asymptotic representations of the wave motions are derived for large time with a fixed distance-to-time ratio with the Stokes and Scorer methods of stationary phase.It is shown that there are two different modes,namely the surface and interfacial wave modes.The wave systems observed depend on the relation between the observer's moving speed and the intrinsic minimal and maximal group velocities.

  8. Summary Report on Gamma Radiolysis of TBP/n-dodecane in the Presence of Nitric Acid Using the Radiolysis/Hydrolysis Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Dean R. Peterman; Bruce J. Mincher; Catherine L. Riddle; Richard D. Tillotson


    Design and installation has been completed for a state-of-the-art radiolysis/hydrolysis test loop system. The system is used to evaluate the effects of gamma radiolysis and acid hydrolysis on the stability and performance of solvent extraction process solvents. The test loop is comprised of two main sections; the solvent irradiation and hydrolysis loop and the solvent reconditioning loop. In the solvent irradiation and hydrolysis loop, aqueous and organic phases are mixed and circulated through a gamma irradiator until the desired absorbed dose is achieved. Irradiation of the mixed phases is more representative of actual conditions in a solvent extraction process. Additionally, the contact of the organic phase with the aqueous phase will subject the solvent components to hydrolysis. This hydrolysis can be accelerated by controlling the system at an elevated temperature. At defined intervals, the organic from the irradiation/hydrolysis loop will be transferred to the solvent reconditioning loop where the solvent is contacted with scrub, strip, and solvent wash solutions which simulate process flowsheet conditions. These two processes are repeated until the total desired dose is achieved. Since all viable solvent extraction components in an advanced fuel cycle must exhibit high radiolytic and hydrolytic stability, this test loop is not limited to any one solvent system but is applicable to all systems of interest. Also, the test loop is not limited to testing of process flowsheets. It is also a valuable tool in support of fundamental research on newly identified extractants/modifiers and the impact of gamma radiation on their stability in a dynamic environment. The investigation of the radiolysis of a TBP/n-dodecane process solvent in contact with aqueous nitric acid has been performed. These studies were intended to confirm/optimize the operability of the test loop system. Additionally, these data are directly applicable to numerous other solvent extraction

  9. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters. (United States)

    Inoue, Yuki; Hamada, Takaho; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru


    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2).

  10. Identification of a Segment of the Yield Surface of a Two-Layer Pa38/M2R Composite (United States)

    Uscinowicz, R. R.


    The aim of this study was to identify the initial yield surface of a two-layer aluminum alloy-copper composite in the range of small elastic-plastic deformations. Experimental tests in a plane stress state were conducted by loading tubular composite specimens with various combinations of axial forces and torque. The metal layers were joined together by using an epoxy resin. Independent studies were carried out for component of the composite under identical conditions. The yield surfaces obtained were compared with those given by the Huber-von Mises-Hencky and Tresca-Guest yield criteria. The yield criterion for the tested composite found by using a modified form of the rule of mixtures is presented. The yield surfaces of a Pa38/M2R composite and its components demonstrated the isotropic hardening.

  11. Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications

    KAUST Repository

    Elshurafa, Amro M.


    In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single-layer MEMS fractal capacitors. Explicitly, a capacitor with a woven structure and another with an interleaved configuration were fabricated in the standard PolyMUMPS surface micromachining process and tested at S-band frequencies. The self-resonant frequencies of the fabricated capacitors were close to 10GHz, which is better than that of the parallel-plate capacitor, which measured only 5.5GHz. Further, the presented capacitors provided a higher capacitance when compared with the state-of-the-art-reported MEMS fractal capacitors created using a single layer at the expense of a lower quality factor. © 2012 The Institution of Engineering and Technology.

  12. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters

    CERN Document Server

    Inoue, Yuki; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru


    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for the use at cryogenic temperatures in millimeter wave measurements. Thermally- sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background (CMB) polarization measurements, such as POLARBEAR-2 (PB-2).

  13. Efficient and stable proton acceleration by irradiating a two-layer target with a linearly polarized laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. Y.; Yan, X. Q.; Chen, J. E.; He, X. T. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China) and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Ma, W. J.; Bin, J. H.; Schreiber, J.; Tajima, T.; Habs, D. [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Am Coulombwall 1, 85748 Garching (Germany) and Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany)


    We report an efficient and stable scheme to generate {approx}200 MeV proton bunch by irradiating a two-layer targets (near-critical density layer+solid density layer with heavy ions and protons) with a linearly polarized Gaussian pulse at intensity of 6.0 Multiplication-Sign 10{sup 20} W/cm{sup 2}. Due to self-focusing of laser and directly accelerated electrons in the near-critical density layer, the proton energy is enhanced by a factor of 3 compared to single-layer solid targets. The energy spread of proton is also remarkably reduced. Such scheme is attractive for applications relevant to tumor therapy.

  14. Hierarchical modeling and control of hybrid systems with two layers; Hierarchische Modellierung und Regelung hybrider Systeme auf zwei Ebenen

    Energy Technology Data Exchange (ETDEWEB)

    Stursberg, Olaf; Paschedag, Tina; Rungger, Matthias; Ding, Hao [Kassel Univ. (Germany). Fachgebiet Regelungs- und Systemtheorie


    While hybrid dynamic models are, to a certain degree, established for modeling systems with heterogeneous dynamics, most approaches for design and analysis of hybrid systems are restricted to monolithic models without hierarchy. This contribution first shows, how modular hybrid systems with two layers of decision, as appropriate for representing manufacturing systems for example, can be modeled systematically. The second part proposes a technique for fixing discrete inputs (for coordinating control) and continuous inputs (for embedded continuous controllers) in combination. The method uses a graph-based search on the upper decision layer, while principles of predictive control are used on the lower layer. The procedure of modeling and control is illustrated for a manufacturing process. (orig.)

  15. Two-layer optical model of skin for early, non-invasive detection of wound development on the diabetic foot (United States)

    Yudovsky, Dmitry; Nouvong, Aksone; Schomacker, Kevin; Pilon, Laurent


    Foot ulceration is a debilitating comorbidity of diabetes that may result in loss of mobility and amputation. Optical detection of cutaneous tissue changes due to inflammation and necrosis at the preulcer site could constitute a preventative strategy. A commercial hyperspectral oximetry system was used to measure tissue oxygenation on the feet of diabetic patients. A previously developed predictive index was used to differentiate preulcer tissue from surrounding healthy tissue with a sensitivity of 92% and specificity of 80%. To improve prediction accuracy, an optical skin model was developed treating skin as a two-layer medium and explicitly accounting for (i) melanin content and thickness of the epidermis, (ii) blood content and hemoglobin saturation of the dermis, and (iii) tissue scattering in both layers. Using this forward model, an iterative inverse method was used to determine the skin properties from hyperspectral images of preulcerative areas. The use of this information in lowering the false positive rate was discussed.

  16. Oblique wave scattering by an undulating porous bottom in a two-layer ice-covered fluid (United States)

    Panda, Srikumar


    The present study analyzes the reflection and transmission phenomenon of water-waves in a two-layer ice-covered system. The upper layer is covered by an ice-sheet, whereas the bottom of the lower layer is undulated and permeable. By using regular perturbation analysis and Fourier transform technique, the problem is solved and the first order reflection and transmission coefficients are determined. It is found that these coefficients depend on the shape as well as the permeability of the undulating bottom. Therefore, from the practical viewpoint, an undulating bottom topography is considered to determine all the aforesaid coefficients. The role of various system parameters, such as porosity, angle of incidence and ice parameters, are discussed to analyze the transformation of incident water wave energy from one layer to another layer. The outcomes are demonstrated in graphical forms.

  17. Synthesis and absorbing mechanism of two-layer microwave absorbers containing polycrystalline iron fibers and carbonyl iron (United States)

    Ding, Qingwei; Zhang, Mingang; Zhang, Cunrui; Qian, Tianwei


    Polycrystalline iron fibers were fabricated by α-FeOOH fiber precursors. Two-layer microwave absorber had been prepared by as-prepared polycrystalline iron fibers and carbonyl iron. The structure, morphology and properties of the composites were characterized with X-ray diffraction, scanning electron microscope and Network Analyzer. The complex permittivity and reflection loss (dB) of the composites were measured employing vector network analyzer model PNA 3629D vector in the frequency range between 30 and 6000 MHz. The thickness effect of the carbonyl iron layer on the microwave loss properties of the composites was investigated. A possible microwave-absorbing mechanism of polycrystalline iron fibers/carbonyl iron composite was proposed. The polycrystalline iron fibers/carbonyl iron composite can find applications in suppression of electromagnetic interference, and reduction of radar signature.

  18. Synchronization in a coupled two-layer quasigeostrophic model of baroclinic instability – Part 1: Master-slave configuration

    Directory of Open Access Journals (Sweden)

    P. L. Read


    Full Text Available Synchronization is studied using a pair of diffusively-coupled, two-layer quasi-geostrophic systems each comprising a single baroclinic wave and a zonal flow. In particular, the coupling between the systems is in the well-known master-slave or one-way configuration. Nonlinear time series analysis, phase dynamics, and bifurcation diagrams are used to study the dynamics of the coupled system. Phase synchronization, imperfect synchronization (phase slips, or complete synchronization are found, depending upon the strength of coupling, when the systems are either in a periodic or a chaotic regime. The results of investigations when the dynamics of each system are in different regimes are also presented. These results also show evidence of phase synchronization and signs of chaos control.

  19. Monte carlo diffusion hybrid model for photon migration in a two-layer turbid medium in the frequency domain. (United States)

    Alexandrakis, G; Farrell, T J; Patterson, M S


    We propose a hybrid Monte Carlo (MC) diffusion model for calculating the spatially resolved reflectance amplitude and phase delay resulting from an intensity-modulated pencil beam vertically incident on a two-layer turbid medium. The model combines the accuracy of MC at radial distances near the incident beam with the computational efficiency afforded by a diffusion calculation at further distances. This results in a single forward calculation several hundred times faster than pure MC, depending primarily on model parameters. Model predictions are compared with MC data for two cases that span the extremes of physiologically relevant optical properties: skin overlying fat and skin overlying muscle, both in the presence of an exogenous absorber. It is shown that good agreement can be achieved for radial distances from 0.5 to 20 mm in both cases. However, in the skin-on-muscle case the choice of model parameters and the definition of the diffusion coefficient can lead to some interesting discrepancies.

  20. A two-layer depth-averaged approach to describe the regime stratification in collapses of dry granular columns (United States)

    Sarno, L.; Carravetta, A.; Martino, R.; Tai, Y. C.


    The dynamics of dry granular flows is still insufficiently understood. Several depth-averaged approaches, where the flow motion is described through hydrodynamic-like models with suitable resistance laws, have been proposed in the last decades to describe the propagation of avalanches and debris flows. Yet, some important features of the granular flow dynamics cannot be well delivered. For example, it is very challenging to capture the progressive deposition process, observed in collapses and dam-break flows over rough beds, where an upper surface flow is found to coexist with a lower creeping flow. The experimental observations of such flows suggest the existence of a flow regime stratification caused by different momentum transfer mechanisms. In this work, we propose a two-layer depth-averaged model, aiming at describing such a stratification regime inside the flowing granular mass. The model equations are derived for both two-dimensional plane and axi-symmetric flows. Mass and momentum balances of each layer are considered separately, so that different constitutive laws are introduced. The proposed model is equipped with a closure equation accounting for the mass flux at the interface between the layers. Numerical results are compared with experimental data of axi-symmetric granular collapses to validate the proposed approach. The model delivers sound agreement with experimental data when the initial aspect ratios are small. In case of large initial aspect ratios, it yields a significant improvement in predicting the final shape of deposit and also the run-out distances. Further comparisons with different numerical models show that the two-layer approach is capable of correctly describing the main features of the final deposit also in the case of two-dimensional granular collapses.

  1. Mem-ADSVM: A two-layer multi-label predictor for identifying multi-functional types of membrane proteins. (United States)

    Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan


    Identifying membrane proteins and their multi-functional types is an indispensable yet challenging topic in proteomics and bioinformatics. However, most of the existing membrane-protein predictors have the following problems: (1) they do not predict whether a given protein is a membrane protein or not; (2) they are limited to predicting membrane proteins with single-label functional types but ignore those with multi-functional types; and (3) there is still much room for improvement for their performance. To address these problems, this paper proposes a two-layer multi-label predictor, namely Mem-ADSVM, which can identify membrane proteins (Layer I) and their multi-functional types (Layer II). Specifically, given a query protein, its associated gene ontology (GO) information is retrieved by searching a compact GO-term database with its homologous accession number. Subsequently, the GO information is classified by a binary support vector machine (SVM) classifier to determine whether it is a membrane protein or not. If yes, it will be further classified by a multi-label multi-class SVM classifier equipped with an adaptive-decision (AD) scheme to determine to which functional type(s) it belongs. Experimental results show that Mem-ADSVM significantly outperforms state-of-the-art predictors in terms of identifying both membrane proteins and their multi-functional types. This paper also suggests that the two-layer prediction architecture is better than the one-layer for prediction performance. For reader׳s convenience, the Mem-ADSVM server is available online at

  2. Improved lumped models for transient combined convective and radiative cooling of a two-layer spherical fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alice Cunha da; Su, Jian, E-mail:, E-mail: [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)


    The High Temperature Gas cooled Reactor (HTGR) is a fourth generation thermal nuclear reactor, graphite-moderated and helium cooled. The HTGRs have important characteristics making essential the study of these reactors, as well as its fuel element. Examples of these are: high thermal efficiency,low operating costs and construction, passive safety attributes that allow implication of the respective plants. The Pebble Bed Modular Reactor (PBMR) is a HTGR with spherical fuel elements that named the reactor. This fuel element is composed by a particulate region with spherical inclusions, the fuel UO2 particles, dispersed in a graphite matrix and a convective heat transfer by Helium happens on the outer surface of the fuel element. In this work, the transient heat conduction in a spherical fuel element of a pebble-bed high temperature reactor was studied in a transient situation of combined convective and radiative cooling. Improved lumped parameter model was developed for the transient heat conduction in the two-layer composite sphere subjected to combined convective and radiative cooling. The improved lumped model was obtained through two-point Hermite approximations for integrals. Transient combined convective and radiative cooling of the two-layer spherical fuel element was analyzed to illustrate the applicability of the proposed lumped model, with respect to die rent values of the Biot number, the radiation-conduction parameter, the dimensionless thermal contact resistance, the dimensionless inner diameter and coating thickness, and the dimensionless thermal conductivity. It was shown by comparison with numerical solution of the original distributed parameter model that the improved lumped model, with H2,1/H1,1/H0,0 approximation yielded significant improvement of average temperature prediction over the classical lumped model. (author)

  3. Radiation chemical behaviour of actinides in extraction systems. 1. Pusup((4)), Npsup((4)), Thsup((4)) in 30% tbp-n-dodecane solution during. gamma. -radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Vladimirova, M.V.; Fedoseev, D.A.; Kulikov, I.A.; Milovanova, A.S.; Bojkova, I.A.; Sosnovskij, O.A.; Kermanova, N.V.; Bulkin, V.I.


    Physicochemical state (valent, complex, aggregative) of Pusup((4)), Npsup((4)) and Thsup((4)) in gamma irradiated TBP solutions in n-dodecane is studied by the spectrophotometric method. Mono- and dibutylphosphoric acids (MBPA and DBPA) accumulating in the irradiated organic solution form with metal ions stable complexes and precipitates impeding in such a way processes of their reextraction. It is determined that ..gamma..-irradiation of investigated solutions does not result in the change of valence and the formation of complexes with DBPA is the main process determining radiation chemical behaviour of Pusup((4)), Npsup((4)) and Thsup((4)). Absorption spectra of irradiated and nonirradiated solutions and dependences of their optical density on the absorbed dose are presented.

  4. Study on the Extraction of Actinides From Simulated High-level Liquid Waste by Mixture of DHDECMP and TBP in Kerosene

    Institute of Scientific and Technical Information of China (English)


    The distribution ratios of U(VI), Np(V), Pu(IV) and Am(III) are measured by the single stage extraction experiments of simulated high-level liquid waste with 22%DHDECMP-42%TBP/OK. The extraction behavior of U, Np, Pu and Am in simulated high-level liquid waste is determined on miniature countercurrent centrifugal contactor cascade (6 stages for extraction, 2 stages for scrubbing, 6 stages for stripping, AF : AX : AS=1 : 1.5 : 0.5; BF : BX=1 : 1). The experimental results show that removal efficiency of U(VI), Np(V), Pu(IV) and Am(III) from simulated high-level liquid waste, all of them ,is equal or more than 99.9%. The stripping efficiency of U(VI),

  5. radiation chemical behavior of actinides in extraction systems. III. Pu(IV) Precipitates from gamma -irradiated 30% tbp + n-dodecane

    Energy Technology Data Exchange (ETDEWEB)

    Vladimirova, M.V.; Boikova, I.A.; Fedoseev, D.A.; Teterin, E.G.


    Spectrophotometric, gravimetric, and ..gamma..-spectrometric analyses, together with solubility and IR methods, were used to investigate the composition and structure, as well as the conditions and behavior in various polar and low-polarity solvents, of Pu(IV) precipitates formed in the ..gamma..-irradiated system 30% TBP + n-dodecane. It was found that the formation of precipitates in solutions containing Pu(IV) in the range 4.10/sup -3/ to 2.10/sup -2/ M occurs at an absorbed ..gamma..-radiation doses E..gamma.. in the range 2.10/sup 5/ to 2.6.10/sup 6/ Gy. At the same time the molar ratio of DBPA (formed by the ..gamma..-radiolysis of TBP) to metal lies in the range 3-5. In the given range of values of E..gamma.. effectively all the plutonium passes into the precipitate. The precipitates form a gelatinous mass. 30-50 wt. % of which consists of the mother liquor. The plutonium content amounts to 11-14 wt. %. The molar ratios of DBPA and MBPA to plutonium (nD and nM, respectively) in precipitates formed at values of E..gamma.. in the range 7.0.10/sup 5/ to 2.6.10/sup 6/ Gy are 2.9 +/- 0.5 and 0.5 +/0.1, respectively. Analyses of the IR spectra of washed and unwashed precipitates indicate the presence of hydrogen-bonded DMPA, carbonyl compounds (butyraldehyde or the anhydride), and NO/sub 3//sup -/ ions in precipitates washed with n-dodecane and the absence of these components in precipitates washed with ethanol. On the basis of the experimental data assumptions are made about the composition of the precipitates formed at doses E..gamma.. in the range 2.10/sup 5/ to 2.6.10/sup 6/ Gy.

  6. Anti-inflammatory activity of the artificial antioxidants 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP), and their various combinations. (United States)

    Murakami, Yukio; Kawata, Akifumi; Katayama, Tadashi; Fujisawa, Seiichiro


    The artificial complex phenols, 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP) exert efficient antioxidant activity; however, they are considerable toxic and potentially tumor-promoting. These phenols, particularly in combinations, have enhanced antioxidant activity due to synergistic interactions and produce bioactive intermediates such as quinone methide. We investigated the anti-inflammatory activity of BHA, BHT and TBP, and combinations of BHT/BHA (in molar ratios of 1:1, 1:2, 1:3 and 2:1), BHT/TBP (1:1), and BHA/TBP (1:1), using gene-expression systems for cyclooxygenase-2 (Cox2) and tumor necrosis facto-alpha (Tnfa) in RAW264.7 cells. The inhibitory effects of BHA, BHT and TBP on expression of Cox2 and Tnfa genes upon stimulation with Escherichia coli lipopolysaccharide (LPS) or Porphyomonas gingivalis (Pg) fimbriae were determined using real-time polymerase chain reaction. The inhibitory effect on expression of Cox2 and Tnfa genes upon stimulation with LPS and fimbriae was greatly enhanced by the combination of two antioxidants (molar ratio 1:1), BHT/BHA. In addition, that of the Cox2 gene, but not of Tnfa gene was slightly enhanced by a combination of equimolar BHT/TBP and BHA/TBP. None of the antioxidants alone exerted any anti-inflammatory activity upon stimulation with LPS, but a slight anti-inflammatory activity was observed upon stimulation with Pg fimbriae. The inhibitory effect of the BHT/BHA combination on expression of Cox2 mRNA upon stimulation with LPS was investigated at afferent molar ratios, and a molar ratio of 1:1 was found to have considerably less effect than a molar ratio of 1:2 or 2:1. The 1:3 combination had no effect. The combination of BHT and BHA at a molar ratio of 0.5-2 exerts potent anti-inflammatory activity. This anti-inflammatory activity on the generation of inflammatory mediators in LPS-activated RAW264.7 cells may be attributable to complex synergistic

  7. Two-layer ZnO nanowire arrays: Fabrication and its photovoltaic property sensitized by CdSe and CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jingzhi [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Wang, Jianxiong; Sun, Xiaowei [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)


    Two-layer ZnO nanowire arrays have been synthesized by a low temperature hydrothermal method. The two-layer structure enables the absorption of CdSe and CdS quantum dots (QDs) on different nanostructured layers, respectively. Solar cell based on the QD sensitized ZnO nanowire arrays is fabricated. Because sequential light adsorption of different sensitizers happens in two different layers, the photoanode can reduce the interaction possibility among different QDs and extend the absorption range, and result in improved photovoltaic properties. - Highlights: • Two-layer ZnO nanowire array has been synthesized by a low temperature hydrothermal. • A two-layer quantum dot sensitized ZnO nanowire array solar cell has been fabricated. • The structure can reduce interaction possibility among different quantum dots. • The structure can extend the range of light absorption.

  8. Forced phase-locked states and information retrieval in a two-layer network of oscillatory neurons with directional connectivity (United States)

    Kazantsev, Victor; Pimashkin, Alexey


    We propose two-layer architecture of associative memory oscillatory network with directional interlayer connectivity. The network is capable to store information in the form of phase-locked (in-phase and antiphase) oscillatory patterns. The first (input) layer takes an input pattern to be recognized and their units are unidirectionally connected with all units of the second (control) layer. The connection strengths are weighted using the Hebbian rule. The output (retrieved) patterns appear as forced-phase locked states of the control layer. The conditions are found and analytically expressed for pattern retrieval in response on incoming stimulus. It is shown that the system is capable to recover patterns with a certain level of distortions or noises in their profiles. The architecture is implemented with the Kuramoto phase model and using synaptically coupled neural oscillators with spikes. It is found that the spiking model is capable to retrieve patterns using the spiking phase that translates memorized patterns into the spiking phase shifts at different time scales.

  9. Spin torque driven dynamics of a coupled two-layer structure: Interplay between conservative and dissipative coupling (United States)

    Romera, M.; Lacoste, B.; Ebels, U.; Buda-Prejbeanu, L. D.


    The general concepts of spin wave theory are adapted to the spin torque driven dynamics of a self-polarized system based on two layers coupled via interlayer exchange (conservative coupling) and mutual spin torque (dissipative coupling). An analytical description of the nonlinear dynamics is proposed and validated through numerical simulations. In contrast to the single layer model, the phase equation of the coupled system has a contribution coming from the dissipative part of the LLGS equation. It is shown that this is a major contribution to the frequency mandatory to describe well the most basic features of the dynamics of this coupled system. Using the proposed model a specific feature of coupled dynamics is addressed: the redshift to blueshift transition observed in the frequency current dependence of this kind of exchange coupled systems upon increasing the applied field. It is found that the blueshift regime can only occur in a region of field where the two linear eigenmodes contribute equally to the steady state mode (i.e., high mode hybridization). Finally, a general perturbed Hamiltonian equation for the coupled system is proposed.

  10. TargetCrys: protein crystallization prediction by fusing multi-view features with two-layered SVM. (United States)

    Hu, Jun; Han, Ke; Li, Yang; Yang, Jing-Yu; Shen, Hong-Bin; Yu, Dong-Jun


    The accurate prediction of whether a protein will crystallize plays a crucial role in improving the success rate of protein crystallization projects. A common critical problem in the development of machine-learning-based protein crystallization predictors is how to effectively utilize protein features extracted from different views. In this study, we aimed to improve the efficiency of fusing multi-view protein features by proposing a new two-layered SVM (2L-SVM) which switches the feature-level fusion problem to a decision-level fusion problem: the SVMs in the 1st layer of the 2L-SVM are trained on each of the multi-view feature sets; then, the outputs of the 1st layer SVMs, which are the "intermediate" decisions made based on the respective feature sets, are further ensembled by a 2nd layer SVM. Based on the proposed 2L-SVM, we implemented a sequence-based protein crystallization predictor called TargetCrys. Experimental results on several benchmark datasets demonstrated the efficacy of the proposed 2L-SVM for fusing multi-view features. We also compared TargetCrys with existing sequence-based protein crystallization predictors and demonstrated that the proposed TargetCrys outperformed most of the existing predictors and is competitive with the state-of-the-art predictors. The TargetCrys webserver and datasets used in this study are freely available for academic use at: .

  11. A novel technique for chest drain removal using a two layer method with triclosan-coated sutures (United States)

    Yokoyama, Yujiro; Nakagomi, Takahiro; Shikata, Daichi


    In thoracic surgery, a thoracic drain is always inserted after the surgical procedure. Repair of the wound after removal of the thoracic tube is performed postoperatively, but no universally standard methods currently exists for this tube removal. Here we report a technique using triclosan-coated sutures that is used in thoracic surgery in our hospital. There are several advantages of this technique. First, there is no need for stitches removal on follow-up. Second, it prevents the leakage of pleural exudate because of the tight two-layer sutures. In addition, it was observed to be superior in terms of both wound healing and cosmetic aspects, due to the layer-to-layer sutures. The use of triclosan-coated sutures helps prevent infection and empyema is quite unlikely to occur as the result of the tight ligating of the muscular layer using these sutures. We applied this method in 168 patients over a period of 24 months. There were no complications on removal of the chest tube such as infection, fluid leakage or opening of the surgical wound. PMID:28203426

  12. Diffraction of Oblique Water Waves by Small Uneven Channel-bed in a Two-layer Fluid

    Institute of Scientific and Technical Information of China (English)

    Smrutiranjan Mohapatra


    Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.

  13. An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation. (United States)

    Guan, C; Xie, H J; Wang, Y Z; Chen, Y M; Jiang, Y S; Tang, X W


    An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems.

  14. Multiresidue analysis of pesticides in vegetables and fruits using two-layered column with graphitized carbon and water absorbent polymer. (United States)

    Obana, H; Akutsu, K; Okihashi, M; Hori, S


    A high-throughput multiresidue analysis of pesticides in non-fatty vegetables and fruits was developed. The method consisted of a single extraction and a single clean-up procedure. Food samples were extracted with ethyl acetate and the mixture of extract and food dregs were poured directly into the clean-up column. The clean-up column consisted of two layers of water-absorbent polymer (upper) and graphitized carbon (lower), which were packed in a reservoir (75 ml ) of a cartridge column. The polymer removed water in the extract while the carbon performed clean-up. In a recovery test, 110 pesticides were spiked and average recoveries were more than 95% from spinach and orange. Most pesticides were recovered in the range 70-115% with RSD usually < 10% for five experiments. The residue analyses were performed by the extraction of 12 pesticides from 13 samples. The two methods resulted in similar residue levels except chlorothalonil in celery, for which the result was lower with the proposed method. The results confirmed that the proposed method could be applied to monitoring of pesticide residue in foods.

  15. Thickness Determination for a Two-Layered Composite of a Film and a Plate by Low-Frequency Ultrasound

    Institute of Scientific and Technical Information of China (English)

    MAO Jie; LI Ming-Xuan; WANG Xiao-Min


    We present an ultrasonic method for determining the thickness of a composite consisting of a soft thin film attached to a hard plate substrate, by resonance spectra in the low frequency region. The interrogating waves can be incident only to the two-layered composite from the substrate side. The reflection spectra are obtained by FFT analysis of the compressive pulsed echoes from the composite, and the thicknesses of the film and the substrate are simultaneously inversed by the simulated annealing method from the resonant frequencies knowing other acoustical parameters in prior. The sensitivity of the method to individual thickness, its convergence and stability against experimental noises are studied. Experiment with interrogating wavelength 4 times larger than the film thickness in a sample of a polymer film (0.054 mm) on an aluminium plate (6.24 mm) verifies the validity of the method. The average relative errors in the measurement of the thicknesses of the film and the substrate are found to be -4.1% and -0.62%, respectively.

  16. Diffraction of oblique water waves by small uneven channel-bed in a two-layer fluid (United States)

    Mohapatra, Smrutiranjan


    Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.

  17. Reflection of a plane wave from a two-layered seafloor with non-parallel interface between the layers. (United States)

    Papadakis, Panagiotis I; Piperakis, George S; Kalogerakis, Michael A


    This work studies the reflection coefficient of a plane wave incident on a seafloor consisting of two layers (sediment and substrate), whose interface is linear but not parallel to the water-sediment interface. This is an extension of the well-established and studied reflection coefficient concept for seafloors with parallel layers. Moreover this study introduces the concept of the Coherent Reflection Coefficient (CRC) that extends the usual Rayleigh reflection coefficient definition not only at the water-sediment interface but inside the water column as well. The mathematical formulation of the CRC is derived and its numerical implementation is explained. Based on this implementation a numerical code is developed and incorporated-among other codes-in a user-friendly graphics toolbox that was built to facilitate CRC calculations. Numerical examples for realistic seafloors are presented and the derived results are compared to similar ones for parallel layers, indicating that even for small inclination angles the reflection coefficient difference between parallel and slanted interface layers is substantial, hence cannot be ignored. An imminent application of the extended seafloor model and the CRC introduced in this work is the enhancement of geophysics inversion schemes for the estimation of the seafloor parameters.

  18. Calculation of the outcomes of remodeling of arteries subjected to sustained hypertension using a 3D two-layered model. (United States)

    Rachev, Alexander; Taylor, W Robert; Vito, Raymond P


    Arteries manifest a remodeling response to long-term alterations in arterial pressure and blood flow by changing geometry, structure, and composition through processes driven by perturbations of the local stresses in the vascular wall from their baseline values. The objective of this study is twofold--to develop a general method for calculating the remodeling responses of an artery considered as a two-layered tube; and to provide results for adaptive and maladaptive remodeling of a coronary artery. By formulating an inverse problem of vascular mechanics, the geometrical dimensions and mechanical properties of an artery are calculated from a prescribed deformed configuration, stress field, structural stiffness, and applied load. As an illustrative example we consider a human LAD coronary artery in both a perfect and incomplete adaptive response to a sustained step-wise change in pressure and a maladaptive response due to impaired remodeling of adventitia. The results obtained show that adventitia plays an important role in vascular mechanics when an artery is subjected to high arterial pressure. In addition to its well-known short term function of preventing over-inflation of an artery, it seems reasonable to accept that the manner by which adventitia remodels in response to a chronic increase in pressure is essential for preserving normal arterial function or may lead to an increased risk of developing vascular disorders.

  19. Study of an unitised bidirectional vanadium/air redox flow battery comprising a two-layered cathode (United States)

    grosse Austing, Jan; Nunes Kirchner, Carolina; Hammer, Eva-Maria; Komsiyska, Lidiya; Wittstock, Gunther


    The performance of a unitised bidirectional vanadium/air redox flow battery (VARFB) is described. It contains a two-layered cathode consisting of a gas diffusion electrode (GDE) with Pt/C catalyst for discharging and of an IrO2 modified graphite felt for charging. A simple routine is shown for the modification of a graphite felt with IrO2. A maximum energy efficiency of 41.7% at a current density of 20 mA cm-2 as well as an average discharge power density of 34.6 mW cm-2 at 40 mA cm-2 were obtained for VARFB operation at room temperature with the novel cathode setup. A dynamic hydrogen electrode was used to monitor half cell potentials during operation allowing to quantify the contribution of the cathode to the overall performance of the VARFB. Four consecutive cycles revealed that crossover of vanadium ions took place and irreversible degradation processes within the reaction unit lead to a performance decrease.

  20. On the stability of discrete tripole, quadrupole, Thomson' vortex triangle and square in a two-layer/homogeneous rotating fluid (United States)

    Kurakin, Leonid G.; Ostrovskaya, Irina V.; Sokolovskiy, Mikhail A.


    A two-layer quasigeostrophic model is considered in the f-plane approximation. The stability of a discrete axisymmetric vortex structure is analyzed for the case when the structure consists of a central vortex of arbitrary intensity Γ and two/three identical peripheral vortices. The identical vortices, each having a unit intensity, are uniformly distributed over a circle of radius R in a single layer. The central vortex lies either in the same or in another layer. The problem has three parameters ( R, Γ, α), where α is the difference between layer thicknesses. A limiting case of a homogeneous fluid is also considered. A limiting case of a homogeneous fluid is also considered. The theory of stability of steady-state motions of dynamic systems with a continuous symmetry group G is applied. The two definitions of stability used in the study are Routh stability and G-stability. The Routh stability is the stability of a one-parameter orbit of a steady-state rotation of a vortex multipole, and the G-stability is the stability of a three-parameter invariant set O G , formed by the orbits of a continuous family of steady-state rotations of a multipole. The problem of Routh stability is reduced to the problem of stability of a family of equilibria of a Hamiltonian system. The quadratic part of the Hamiltonian and the eigenvalues of the linearization matrix are studied analytically. The cases of zero total intensity of a tripole and a quadrupole are studied separately. Also, the Routh stability of a Thomson vortex triangle and square was proved at all possible values of problem parameters. The results of theoretical analysis are sustained by numerical calculations of vortex trajectories.

  1. Testing the two-layer model for correcting near-cloud reflectance enhancement using LES/SHDOM-simulated radiances (United States)

    Wen, Guoyong; Marshak, Alexander; Várnai, Tamás.; Levy, Robert


    A transition zone exists between cloudy skies and clear sky; such that, clouds scatter solar radiation into clear-sky regions. From a satellite perspective, it appears that clouds enhance the radiation nearby. We seek a simple method to estimate this enhancement, since it is so computationally expensive to account for all three-dimensional (3-D) scattering processes. In previous studies, we developed a simple two-layer model (2LM) that estimated the radiation scattered via cloud-molecular interactions. Here we have developed a new model to account for cloud-surface interaction (CSI). We test the models by comparing to calculations provided by full 3-D radiative transfer simulations of realistic cloud scenes. For these scenes, the Moderate Resolution Imaging Spectroradiometer (MODIS)-like radiance fields were computed from the Spherical Harmonic Discrete Ordinate Method (SHDOM), based on a large number of cumulus fields simulated by the University of California, Los Angeles (UCLA) large eddy simulation (LES) model. We find that the original 2LM model that estimates cloud-air molecule interactions accounts for 64% of the total reflectance enhancement and the new model (2LM + CSI) that also includes cloud-surface interactions accounts for nearly 80%. We discuss the possibility of accounting for cloud-aerosol radiative interactions in 3-D cloud-induced reflectance enhancement, which may explain the remaining 20% of enhancements. Because these are simple models, these corrections can be applied to global satellite observations (e.g., MODIS) and help to reduce biases in aerosol and other clear-sky retrievals.

  2. Oblique Water Wave Scattering by Bottom Undulation in a Two-layer Fluid Flowing Through a Channel

    Institute of Scientific and Technical Information of China (English)

    Smrutiranjan Mohapatra; Swaroop Nandan Bora


    The problem of oblique wave (internal wave) propagation over a small deformation in a channel flow consisting of two layers was considered.The upper fluid was assumed to be bounded above by a rigid lid,which is an approximation for the free surface,and the lower one was bounded below by an impermeable bottom surface having a small deformation; the channel was unbounded in the horizontal directions.Assuming irrotational motion,the perturbation technique was employed to calculate the first-order corrections of the velocity potential in the two fluids by using Green's integral theorem suitably with the introduction of appropriate Green's functions.Those functions help in calculating the reflection and transmission coefficients in terms of integrals involving the shape function c(x) representing the bottom deformation.Three-dimensional linear water wave theory was utilized for formulating the relevant boundary value problem.Two special examples of bottom deformation were considered to validate the results.Consideration of a patch of sinusoidal ripples (having the same wave number) shows that the reflection coefficient is an oscillatory function of the ratio of twice the x-component of the wave number to the ripple wave number.When this ratio approaches one,the theory predicts a resonant interaction between the bed and the interface,and the reflection coefficient becomes a multiple of the number of tipples.High reflection of incident wave energy occurs if this number is large.Similar results were observed for a patch of sinusoidal tipples having different wave numbers.It was also observed that for small angles of incidence,the reflected energy is greater compared to other angles of incidence up to π / 4.These theoretical observations are supported by graphical results.

  3. A two-layer ONIOM study of thiophene cracking catalyzed by proton- and cation-exchanged FAU zeolite. (United States)

    Sun, Yingxin; Mao, Xinfeng; Pei, Supeng


    A two-layer ONIOM study on the hydrodesulfurization mechanism of thiophene in H-FAU and M-FAU (M = Li(+), Na(+), and K(+)) has been carried out. The calculated results reveal that in H-FAU, for a unimolecular mechanism, the rate-determining step is hydrogenation of alkoxide intermediate. The assistance of H2O and H2S molecules does not reduce the difficulty of the C-S bond cracking step more effectively. A bimolecular hydrodesulfurization mechanism is more favorable due to the lower activation barriers. The rate-determining step is the formation of 2-methylthiophene, not the C-S bond cracking of thiophene. Moreover, the ring opening of thiophene is much easier to occur than the desulfurization step. A careful analysis of energetics indicates that H2S, propene, and methyl thiophene are the major products for the hydrodesulfurization process of thiophene over H-FAU zeolite, in good agreement with experimental findings. In M-FAU zeolites, both unimolecular and bimolecular cracking processes are difficult to occur because of the high energy barriers. Compared to the case on H-FAU, the metal cations on M-FAU increase the difficulty of occurrence of bimolecular polymerization and subsequent C-S bond cracking steps. Graphical abstract Hydrodesulfurization process of thiophene can take place in H-FAU zeolite. Two different mechanisms, unimolecular and bimolecular ones, have been proposed and evaluated in detail. The bimolecular mechanism is more favorable due to lower activation barrier as described in the picture above. Our calculated data indicate that H2S, propene, and methylthiophene are the major products, in good agreement with experimental observations. The effect of metal cations on the reaction mechanism is also investigated in this work.

  4. Synchronization and chaos control in a periodically forced quasi-geostrophic two-layer model of baroclinic instability

    Directory of Open Access Journals (Sweden)

    F. J. R. Eccles


    Full Text Available Cyclic forcing on many timescales is believed to have a significant effect on various quasi-periodic, geophysical phenomena such as El Niño, the Quasi-Biennial Oscillation, and glacial cycles. This variability has been investigated by numerous previous workers, in models ranging from simple energy balance constructions to full general circulation models. We present a numerical study in which periodic forcing is applied to a highly idealised, two-layer, quasi-geostrophic model on a β-plane. The bifurcation structure and (unforced behaviour of this particular model has been extensively examined by Lovegrove et al. (2001 and Lovegrove et al. (2002. We identify from their work three distinct regimes on which we perform our investigations: a steady, travelling wave regime, a quasi-periodic, modulated wave regime and a chaotic regime. In the travelling wave regime a nonlinear resonance is found. In the periodic regime, Arnol'd tongues, frequency locking and a Devil's staircase is seen for small amplitudes of forcing. As the forcing is increased the Arnol'd tongues undergo a period doubling route to chaos, and for larger forcings still, the parameter space we explored is dominated by either period 1 behaviour or chaotic behaviour. In the chaotic regime we extract unstable periodic orbits (UPOs and add the periodic forcing at periods corresponding to integer multiples of the UPO periods. We find regions of synchronization, similar to Arnol'd tongue behaviour but more skewed and centred approximately on these periods. The regions where chaos suppression took place are smaller than the synchronization regions, and are contained within them.

  5. Three-dimensional linear instability in pressure-driven two-layer channel flow of a Newtonian and a Herschel-Bulkley fluid (United States)

    Sahu, K. C.; Matar, O. K.


    The three-dimensional linear stability characteristics of pressure-driven two-layer channel flow are considered, wherein a Newtonian fluid layer overlies a layer of a Herschel-Bulkley fluid. We focus on the parameter ranges for which Squire's theorem for the two-layer Newtonian problem does not exist. The modified Orr-Sommerfeld and Squire equations in each layer are derived and solved using an efficient spectral collocation method. Our results demonstrate the presence of three-dimensional instabilities for situations where the square root of the viscosity ratio is larger than the thickness ratio of the two layers; these "interfacial" mode instabilities are also present when density stratification is destabilizing. These results may be of particular interest to researchers studying the transient growth and nonlinear stability of two-fluid non-Newtonian flows. We also show that the "shear" modes, which are present at sufficiently large Reynolds numbers, are most unstable to two-dimensional disturbances.

  6. Theoretical research on enhancement of gain for Ni-like Ag 13.9 nm x-ray laser using a new two-layer target

    Institute of Scientific and Technical Information of China (English)

    Zhang Guo-Ping; Zhang Tan-Xin; Zheng Wu-Di; Qiao Xiu-Mei


    For experiments such as on Ni-like Ag x-ray laser, driven by 1ω laser, the gain region is only several nrn depth near the target surface, this paper proposes a new two-layer target, in which a thin layer (several nm depth) of silver is plated on the surface of some other materials. Furthermore, the Ni-like Ag 13.9 nm x-ray laser produced by three new kinds of two-layer target with CH, Al and Ge as foundation, was theoretically studied.

  7. Micro distillation of crude oil to obtain TBP (True Boiling Points) curve; Micro destilacao de petroleo para obtencao da curva PEV (Ponto de Ebulicao Verdadeiro)

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Maria de Lourdes S.P.; Mendes, Luana de Jesus [Fundacao Gorceix, Ouro Preto, MG (Brazil); Medina, Lilian Carmen [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)


    PETROBRAS and others petroleum companies adopt the ASTM norms as reference method for oil distillation, ASTM D2892 (2005) that uses columns with 14 to 18 theoretical plates and the ASTM D 5236 (2003) , that distills mixture of heavy hydrocarbons with boiling point over 150 deg C. The result of these two distillations is the TBP (True Boiling Point) curve that is the main tool to define the yield of oil derivatives, the 'royalties' payment, the oil price for commercialization and the logistic support of oil location or in new plants projects of distillation and optimization studies. This procedure has some limitations as the volume sample, at least 1L, and the time of distillation, 2 to 4 days. The objective of this work is to propose a new alternative to attain de PEV curve, developing a new methodology using micro scale distillation that uses a more efficient column than the conventional method. Graphics of both methods were created and the results between the conventional and the micro distillation received statistical treatment to prove the equivalence between them. (author)

  8. Application of the Baxter model for hard-spheres with surface adhesion to SANS data for the U(VI) - HNO{sub 3}, TBP-n-dodecane system.

    Energy Technology Data Exchange (ETDEWEB)

    Chiarizia, R.; Nash, K. L.; Jensen, M. P.; Thiyagarajan, P.; Littrell, K. C.


    Small-angle neutron scattering (SANS) data for the tri-n-butyl phosphate (TBP)-n-dodecane, HNO{sub 3}-UO{sub 2}(NO{sub 3}){sub 2} solvent extraction system have been interpreted using the Baxter model for hard spheres with surface adhesion. The increase in the scattering intensity in the low Q range observed when increasing amounts of HNO{sub 3} or UO{sub 2}(NO{sub 3}){sub 2} are transferred into the organic phase has been interpreted as arising from interactions between solute particles. The SANS data have been reproduced using a 12--16 {angstrom} diameter of the hard sphere, d{sub hs}, and a 5.6k{sub B}T-7.1k{sub B}T stickiness parameter, {tau}{sup -1}. When in contact with an aqueous phase, TBP in n-dodecane forms small reverse micelles containing three TBP molecules. Upon extraction of water, HNO{sub 3}, and UO{sub 2}(NO{sub 3}){sub 2}, the swollen micelles interact through attractive forces between their polar cores with a potential energy of about 2k{sub B}T and an effective Hamaker constant of about 4k{sub B}T. The intermicellar attraction, under suitable conditions, leads to third-phase formation. Upon phase splitting, most of the solutes in the original organic phase (water, TBP, HNO{sub 3}, and UO{sub 2}(NO{sub 3}){sub 2}) separate in a continuous phase containing interspersed layers of n-dodecane.

  9. A theoretical, two-layer, reduced-gravity model for descending dense water flow on continental shelves/slopes (United States)

    Wang, Jia; Ikeda, Moto; Saucier, Francois J.


    A theoretical, two-layer, reduced-gravity model for descending dense water flow on continental shelves/slopes has been developed to investigate the dynamics of bottom dense water plumes. The model is nonsteady state and includes vertical viscosity, the Coriolis force, and bottom friction. An integral solution rather than a perfect analytical expression is derived and, thus, the Simpson's 1/3 rule to approximate the integral is applied. At the very bottom, the dense water plume moves about 45° to the right (left) in the Northern (Southern) Hemisphere, looking downslope. From the bottom, the velocity vector rotates anticyclonically upward, indicating a bottom Ekman spiral that mimics the atmospheric Ekman boundary layer. The dense water within the bottom Ekman layer obeys a three-force balance, while the dense water above the bottom Ekman layer is governed by a two-force balance, which is a geostrophic flow with superimposed cycloidal inertial oscillations oriented from about 25° to 140° to the right (left) of the downslope direction in the Northern (Southern) Hemisphere. The transport within the bottom Ekman layer is directed about 60-70° to the right (left) of the downslope direction in the Northern (Southern) Hemisphere, forming an offshore (cross-isobath) transport in the absence of eddy flux and wind-forcing. The ratio of offshore transport to alongshore transport within the bottom Ekman layer is about 0.19 (19%), while the ratio above the bottom Ekman layer (i.e., geostrophic layer of the dense water) is only 3% (negligible compared to its alongshore transport), which, however, is equivalent in magnitude to its counterpart in the bottom Ekman layer if O(DE/h) ˜ 0.1 (where DE is the bottom Ekman layer thickness and h is the dense water layer thickness). In other words, the bottom Ekman layer and the geostrophic (dense) layer contribute equivalent dense water offshore (each contributes 50%). The magnitude of the descending dense water velocity depends

  10. Remediation of PCE-contaminated aquifer by an in situ two-layer biobarrier: laboratory batch and column studies. (United States)

    Kao, C M; Chen, S C; Wang, J Y; Chen, Y L; Lee, S Z


    The industrial solvent tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to develop an in situ two-layer biobarrier system consisting of an organic-releasing material layer followed by an oxygen-releasing material layer. The organic-releasing material, which contained sludge cakes from a domestic wastewater treatment plant, is able to release biodegradable organics continuously. The oxygen-releasing material, which contained calcium peroxide, is able to release oxygen continuously upon contact with water. The first organic-releasing material layer was to supply organics (primary substrates) to reductively dechlorinate PCE in situ. The second oxygen-releasing material layer was to release oxygen to aerobic biodegrade or cometabolize PCE degradation byproducts from the first anaerobic layer. Batch experiments were conducted to design and identify the components of the organic and oxygen-releasing materials, and evaluate the organic substrate (presented as chemical oxygen demand (COD) equivalent) and oxygen release rates from the organic-releasing material and oxygen-releasing materials, respectively. The observed oxygen and COD release rates were approximately 0.0368 and 0.0416 mg/d/g of material, respectively. A laboratory-scale column experiment was then conducted to evaluate the feasibility of this proposed system for the bioremediation of PCE-contaminated groundwater. This system was performed using a series of continuous-flow glass columns including a soil column, an organic-releasing material column, two consecutive soil columns, and an oxygen-releasing material column, followed by two other consecutive soil columns. Anaerobic acclimated sludges were inoculated in the first four columns, and aerobic acclimated sludges were inoculated in the last three columns to provide microbial consortia for contaminant biodegradation. Simulated PCE-contaminated groundwater with a

  11. 双亚砜与TBP对铀(Ⅵ)萃取行为的比较%Comparision of extraction of U(Ⅵ) from nitric acid by disulfoxides and TBP

    Institute of Scientific and Technical Information of China (English)

    朱利明; 匡华; 崔立燕; 孙永辉; 曹正白


    研究了PhSO(CH2)nSOPh(n=2、3、4、6)-三氯甲烷体系从硝酸介质中萃取铀的行为。n=2的双亚砜在萃取时出现三相,n=3、4、6的三种双亚砜对铀的萃取规律类似于TBP,萃取性能略优于TBP。铀的溶剂化数均为1。%The extraction of dioxouranium(Ⅵ) from nitric acid solution byPhSO(CH2)nSOPh (n=2,3,4,6)-trichloromethane was studied. When the disulfoxide was PhSO(CH2)2SOPh, the third phase formed. The extraction laws of dioxouranium(Ⅵ) by the disulfoxides (n=3,4,6) were similar to that by tributyl-phosphate(TBP). Their extracting ability was slightly better than that of TBP.

  12. Synergistic extraction of U(VI) with mixtures of 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (PC-88A) and TBP, TOPO or Cyanex 923

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.K.; Singh, H. [Rare Earth Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Mathur, J.N. [Radiochemistry Div., Bhabha Atomic Research Centre, Trombay, Mumbai (India)


    The extraction of uranium (VI) from hydrochloric acid medium with PC-88A (H{sub 2}A{sub 2} in dimeric form) and neutral organo phosphorous donors like TBP, TOPO and Cyanex 923 (S) in dodecane is reported. Experiments were performed with PC-88A, TOPO and Cyanex 923 alone and with the mixtures of PC-88A with TBP, TOPO or Cyanex 923. The presence of neutral donors in PC-88A solutions gave synergistic enhancement in the extraction of uranium (VI), the order being Cyanex 923 > TOPO > TBP. The species extracted with PC-88A alone is UO{sub 2}(HA{sub 2}){sub 2}, whereas with TOPO or Cyanex 923 alone, it is UO{sub 2}Cl{sub 2}.2S and with the synergistic mixtures it is UO{sub 2}(HA{sub 2}){sub 2}.S. The power dependencies of S and PC-88A under experimental conditions have also been evaluated using non-linear regression analysis. The equilibrium constants of synergistic extraction have been calculated and the mechanism of the extraction is discussed. The effect of different organic diluents on uranium (VI) extraction with PC-88A has also been examined. (orig.)

  13. A two Layer Convecting Mantle With Exchange : A Unified Model Based on Geochemical, Seismic and Heat Flow Observations (United States)

    Allègre, C. J.; Jaupart, C.; Nolet, G.


    -penetrating slabs as emphasized by Fukao and al.(2001) and the recent observation of the large energy spectrum differences at 670 km depth (Gu and al., 2006). We discuss the problem of return flow, which is crucial for both energy budget and convection regime. The recent work on plume by Montelli and al. (2004, 2006) shows the existence of broad plumes in the lower mantle and thin plumes in the upper mantle. d) The estimate of heat flow coming from the lower mantle of 35-32 TW. The work of Davies(1990) and Sleep(1992) shows clearly that this transfer is not the result of plumes reaching the surface, because they correspond at most to 3TW. At the reverse the estimated heat flow carried by the lower mantle plumes is much higher (Nolet and al., 2006). We also discuss the heat flow paradox to explain a Urey ratio of 0.4 with whole mantle convection. In conclusion, we propose mantle with two layers convecting separately but with some exchange of matter, this global exchange corresponding to 1.1024kg since 4.4 Gy. Plume genesis is a two-stage process. Lower mantle plumes heat the Mesosphere boundary layer generating second generation plumes which reach the surface (Allègre and Turcotte; 1983; Allègre, 1987). In the upper mantle itself, we have to distinguish between a vigorously convecting asthenosphere and a sluggish convecting transition zone, both convecting in same cells.

  14. Distribution Coefficient Model of Main Component in Th(NO3)4-UO2 (NO3)2-HNO3-H2 O/30%TBP-dodecane Extraction System%Th(NO3)4-UO2(NO3)2-HNO3-H2 O/30%TBP-正十二烷萃取体系主要组分分配比模型

    Institute of Scientific and Technical Information of China (English)

    于婷; 李峥; 赵皓贵; 何淑华; 何辉; 李晴暖; 张岚


    Based on distribution coefficient data of thorium (Th),uranium (U)and nitric acid in the tributyl phosphate (TBP)extraction system,and by comparing and analyzing the presented distribution coefficient models in the literature,a new mathe-matical distribution coefficient model with relative computer program for simulating the extraction behavior of Th(Ⅳ),U(Ⅵ)and HNO3 in the TBP extraction system.The reliability of the new model with computer program was verified by 34 sets of distribu-tion coefficient data.The calculated results agree well with the experimental data.The results by comparing the actual distribution coefficient data with the computing results indicate that the calculated results by using this new model are more reliable and accu-rate than those of SEPHIS model reported previously.The model presented in this work can be a foundation for simulating the extraction behavior of thorium,uranium and nitric acid in the extraction system of Th (NO3 )4-UO2 (NO3 )2-HNO3-H2 O/30%TBP-dodecane with uranium concentrations from 0 g/L to 100 g/L,thorium from 0 g/L to 232 g/L,and HNO3 from 0 g/L to 4.5 mol/L at 25 ℃.%利用文献报道的Th(NO3)4-UO2(NO3)2-HNO3-H2 O/30%TBP-正十二烷体系各组分的分配比实验数据对现有的分配比模型进行分析和比对,提出了一个计算该体系各组分分配比的新模型。利用34组实验数据对新模型进行了验证,符合情况良好。计算结果表明,本文提出的模型明显优于原模型,可作为Th(NO3)4-UO2(NO3)2-HNO3-H2 O/30%TBP-正十二烷萃取体系中 Th(Ⅳ)、U(Ⅵ)和 HNO3萃取行为计算机模拟的基础。模型建立的条件为:温度,25℃;U(Ⅵ)浓度,0~100 g/L;Th(Ⅳ)浓度,0~232 g/L;硝酸浓度,0~4.5 mol/L。

  15. Kinetics of reductive stripping of Np(VI) by acetohydroxamic acid from 30%TBP/kerosene to nitrate medium using a high-speed stirred cell

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chuanbo; Yan, Taihong; Zuo, Chen; Zheng, Weifang [China Institute of Atomic Energy, Beijing (China)


    The kinetics of reductive stripping of Np(VI) by Acetohydroxamic Acid from 30%TBP/kerosene was investigated using a high-speed stirred cell designed by ourselves. The phase separator for sampling was simple and powerful. The interfacial areas of different stirring speeds were determined by microphotograph method at 21 C before the experiments. The effects of the different parameters as well as temperature were investigated systemically. The results showed that, at 21 C the rate equation is -d[Np(VI)]/dt = k(S/V)[Np(VI)]{sup 0.78}[AHA]{sup 0.46}[HNO{sub 3}]{sup -0.20} - k'(S/V)[Np(V)]{sup 2.87}, where k = (8.7 ± 0.7) x 10{sup -7}(mol/L){sup -0.04} ms{sup -1}, k' = 1.1 ± 0.2(mol/L){sup -2.87} ms{sup -1}, as c[HNO{sub 3}] <=1.0 mol/L, -d[Np(VI)]/dt = k(S/V)[Np(VI)]{sup 0.78}[AHA]{sup 0.46}[HNO{sub 3}]{sup -1.42} - k'(S/V)[Np(V)]{sup 2.87}, where k = (3.2 ± 0.3) x 10{sup -7} (mol/L){sup 1.18} ms{sup -1}, k' = 1.1 ± 0.2(mol/L){sup -2.87} ms{sup -1} as c[HNO{sub 3}] > = 1.0 mol/L, and S is the interfacial area, V the organic phase volume. The reductive stripping process is controlled by chemical reactions (kinetics regime) taking place at the interface. The apparent activation energy is 13.5 ± 0.2 kJ/mol.

  16. Creating and controlling overlap in two-layer networks. Application to a mean-field SIS epidemic model with awareness dissemination

    CERN Document Server

    Juher, David


    We study the properties of the potential overlap between two networks $A,B$ sharing the same set of $N$ nodes (a two-layer network) whose respective degree distributions $p_A(k), p_B(k)$ are given. Defining the overlap coefficient $\\alpha$ as the Jaccard index, we derive upper bounds for the minimum and maximum overlap coefficient in terms of $p_A(k)$, $p_B(k)$ and $N$. We also present an algorithm based on cross-rewiring of links to obtain a two-layer network with any prescribed $\\alpha$ inside the permitted range. Finally, to illustrate the importance of the overlap for the dynamics of interacting contagious processes, we derive a mean-field model for the spread of an SIS epidemic with awareness against infection over a two-layer network, containing $\\alpha$ as a parameter. A simple analytical relationship between $\\alpha$ and the basic reproduction number follows. Stochastic simulations are presented to assess the accuracy of the upper bounds of $\\alpha$ and the predictions of the mean-field epidemic model...

  17. Unconventional but tunable phase transition above the percolation threshold by two-layer conduction in electroless-deposited Au nanofeatures on silicon substrate. (United States)

    Lee, Seung-Hoon; Shin, Muncheol; Hwang, Seongpil; Jang, Jae-Won


    Previous research has shown that disorder, dislocation, and carrier concentration are the main factors impacting transitions in the traditional metal-insulator transition (MIT) and metal-semiconductor transition (MST). In this study, it is demonstrated that a non-traditional metal-semiconductor transition governed by two-layer conduction is possible by tuning the conducting channel of one layer of the two-layer conduction system. By means of the electroless deposition method we produced Au nanofeatures (AuNFs) on p-type silicon (p-Si) as the two-layer conduction system, controlling AuNF coverage (Au%) below and above the percolation threshold (p c). Even when the AuNF coverage percentage is larger than p c, the resistivities of the AuNFs on p-Si show MST as the temperature increases. To demonstrate this finding, we present a conduction model based upon two predominant parallel conductions by AuNFs and p-Si in the present paper. In the results, we show how the temperature of the MST (T MST) is tuned from 145 to 232 K as Au% is changed from 82.7 to 54.3%.

  18. Optimisation on the two-layer stack gamma detectors of CsI(Tl) coupled with a pin photodiode for non-destructive testing. (United States)

    Bai, Jin Hyoung; Whang, Joo Ho


    This paper proposed the two-layer stack scintillator-coupled photodiode detector to improve the measurement accuracy of the gamma-ray scanning. Both MCNPX and DETECT97 code were used to design the detector. The two manufactured two-layer stack gamma detectors were used to measure the density profile of the distillation column of the radiographic non-intrusive process diagnostic area. To compare the measurement accuracy of the density profile through the non-destructive transmission test, the relative error of the four fluids used for the process diagnostics was analysed. To summarise the measurement results with regard to the relative error of the NaI(Tl) detector and the manufactured detector by material as well as the total relative error, the total relative error of the NaI(Tl) detector was about 15.7 %, whereas that of the two-layer stack CsI(Tl) with photodiode detectors were about 5 %. This paper confirmed that the measurement accuracy of the detector proposed was improved by about three times as compared with the NaI(Tl) detector mostly used for non-destructive testing.

  19. Spinocerebellar ataxia type 17: Report of a family with reduced penetrance of an unstable Gln49 TBP allele, haplotype analysis supporting a founder effect for unstable alleles and comparative analysis of SCA17 genotypes

    Directory of Open Access Journals (Sweden)

    Schwinger Eberhard


    Full Text Available Abstract Background Spinocerebellar ataxia type 17 (SCA17, a neurodegenerative disorder in man, is caused by an expanded polymorphic polyglutamine-encoding trinucleotide repeat in the gene for TATA-box binding protein (TBP, a main transcription factor. Observed pathogenic expansions ranged from 43 – 63 glutamine (Gln codons (Gln43–63. Reduced penetrance is known for Gln43–48 alleles. In the vast majority of families with SCA17 an expanded CAG repeat interrupted by a CAA CAG CAA element is inherited stably. Results Here, we report the first pedigree with a Gln49 allele that is a not interrupted, b unstable upon transmission, and c associated with reduced penetrance or very late age of onset. The 76-year-old father of two SCA17 patients carries the Gln49 TBP allele but presents without obvious neurological symptoms. His children with Gln53 and Gln52 developed ataxia at the age of 41 and 50. Haplotype analysis of this and a second family both with uninterrupted expanded and unstable pathological SCA17 alleles revealed a common core genotype not present in the interrupted expansion of an unrelated SCA17 patient. Review of the literature did not present instability in SCA17 families with expanded alleles interrupted by the CAA CAG CAA element. Conclusion The presence of a Gln49 SCA17 allele in an asymptomatic 76-year-old male reams the discussion of reduced penetrance and genotypes producing very late disease onset. In SCA17, uninterrupted expanded alleles of TBP are associated with repeat instability and a common founder haplotype. This suggests for uninterrupted expanded alleles a mutation mechanism and some clinical genetic features distinct from those alleles interrupted by a CAA CAG CAA element.

  20. Supercritical water oxidation of spent extraction solvent simulants

    Institute of Scientific and Technical Information of China (English)

    王帅; 秦强; 陈土方方; 夏晓彬; 马洪军; 乔延波; 何柳斌


    The rapid development of nuclear technology has led to more liquid organic radioactive wastes. Different from the regular aqueous radioactive wastes, these liquids possess a higher hazard potential and cannot be disposed through the conventional methods due to their radioactivity and chemical nature. Spent extraction solvent is a kind of common liquid organic radioactive wastes. In this work, tri-butyl phosphate (TBP), which is more difficult to degrade in the spent extraction solvent, was used as the model compound. Influences of reaction conditions on total organic carbon (TOC) removal and the volume percentage of each gas component under supercritical water oxidation (SCWO) were studied. The SCWO behaviors of spent extraction solvent simulants were studied under the optimal conditions derived from the TBP experiment. The SCWO experiments were studied at 400–550◦C, oxidant stoichiometric ratio of 0–200%, feed concentration of 1.5%–4%and pressure of 25 MPa for 15–75 s. The results show that the TOC removal of the simulants was greater than 99.7%and CH4, H2 and CO were not detected at 550◦C, 25 MPa, oxidant stoichiometric ratio of 150%, feed concentration of 3%, and residence time of 30 s.

  1. Waste treatment in NUCEF facility with silver mediated electrochemical oxidation technique

    Energy Technology Data Exchange (ETDEWEB)

    Umeda, M.; Sugikawa, S. [Tokai Establishment, Japan Atomic Energy Research Institute, Tokai-Mura, Naka-Gun, Ibaraki-Ken (Japan)


    Silver mediated electrochemical oxidation technique has been considered one of promising candidates for alpha-bearing waste treatment. Destruction tests of organic compounds, such as insoluble tannin, TBP and dodecane, were carried out by this technique and the experimental data such as destruction rates, current efficiencies and intermediates were obtained. These compounds could be completely mineralized without the formation of reactive organic nitrate associated to safety hazards. On the basis of these results, the applicability of silver mediated electrochemical oxidation technique to waste treatment in NUCEF was evaluated. (authors)

  2. Heat absorbtion by earth coil systems placed in two layers in one trench. [Heat pumps]. Varmeoptagelse fra jordslanger i to lag i samme grav

    Energy Technology Data Exchange (ETDEWEB)

    Willumsen, O.


    The aim of the project is to evaluate the performance of a new technique of installing earth coil systems for heat pumps. In order to reduce the costs of an efficient heat absorber, two coils were placed in the same trench in two different levels, generally in a depth of 0.7 and 1.1 metres. Usually the total pipe length was increased with 20 - 30% compared to the one-layer design. The digging expences, however, were still smaller than those of the one-layer design. The evaluation is based on measurements on 4 heat pump installations using the two-layer concept, where the extracted heat energy from the higher and lower earth coils were metered individually on a monthly basis. Furthermore, the in- and outlet temperature of the coils and the energy comsumption of the heat pump was measured. The main conclusions of the project are: - A two-layer design leads to a slightly cheaper earth coil. The performance of the earth coil is not negatively affected by this technique, provided that the vertical distance between the coils is at least 0.4 metres at any place. - Two-layer coils may be designed with the same total length as used in one-layer coils - which means half the trench length. This design gives a more intensive exploitation of the available soil area, without decreasing the performance of the heat pump. - The disadvantage of the technique is an increasing risk of earth elevation due to freezing. This risk should be minimized by keeping a minimum distance of 0.40 meters between the individual pipes and thermal insulation if more than two pipes are placed near to each other. (AB).

  3. 双层界面重磁联合反演方法研究%Joint inversion of gravity and magnetic data for a two-layer model

    Institute of Scientific and Technical Information of China (English)

    江凡; 吴健生; 王家林


    Based on the synchronous joint gravity and magnetic inversion of single interface by Pilkington and the need of revealing Cenozoic and crystalline basement thickness in the new round of oil-gas exploration, we propose a joint gravity and magnetic inversion method for two-layer models by concentrating on the relationship between the change of thickness and position of the middle layer and anomaly and discuss the effects of the key parameters. Model tests and application to field data show the validity of this method.

  4. Protein fold recognition with a two-layer method based on SVM-SA, WP-NN and C4.5 (TLM-SNC). (United States)

    Zangooei, Mohammad Hossein; Jalili, Saeed


    The structural knowledge of protein is crucial in understanding its biological role. An effort is made to assign a fold to a given protein in a protein fold recognition problem. A computational Two-Layer Method (TLM) based on the Support Vector Machine (SVM), the Neural Network (NN) and the Decision Tree (C4.5) has been developed in this study for the assignment of a protein sequence to a folding class in SCOP. Prediction accuracy is measured on a dataset and the accuracy of the proposed method is very promising in comparison with other classification methods.

  5. Interaction between transactivation domain of p53 and middle part of TBP-like protein (TLP is involved in TLP-stimulated and p53-activated transcription from the p21 upstream promoter.

    Directory of Open Access Journals (Sweden)

    Ryo Maeda

    Full Text Available TBP-like protein (TLP is involved in transcriptional activation of an upstream promoter of the human p21 gene. TLP binds to p53 and facilitates p53-activated transcription from the upstream promoter. In this study, we clarified that in vitro affinity between TLP and p53 is about one-third of that between TBP and p53. Extensive mutation analyses revealed that the TLP-stimulated function resides in transcription activating domain 1 (TAD1 in the N-terminus of p53. Among the mutants, #22.23, which has two amino acid substitutions in TAD1, exhibited a typical mutant phenotype. Moreover, #22.23 exhibited the strongest mutant phenotype for TLP-binding ability. It is thus thought that TLP-stimulated and p53-dependent transcriptional activation is involved in TAD1 binding of TLP. #22.23 had a decreased transcriptional activation function, especially for the upstream promoter of the endogenous p21 gene, compared with wild-type p53. This mutant did not facilitate p53-dependent growth repression and etoposide-mediated cell-death as wild-type p53 does. Moreover, mutation analysis revealed that middle part of TLP, which is requited for p53 binding, is involved in TLP-stimulated and p53-dependent promoter activation and cell growth repression. These results suggest that activation of the p21 upstream promoter is mediated by interaction between specific regions of TLP and p53.

  6. Efficient calculation of potential distribution in two-layer earth; Niso kozo daichikei ni okeru denki tansa no tame no koritsuteki den`i keisan shuho

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, M.; Okamoto, Y. [Chiba Institute of Technology, Chiba (Japan); Endo, M.; Noguchi, K. [Waseda University, Tokyo (Japan); Teramachi, Y.; Akabane, H. [University of Industrial Technology, Kanagawa (Japan); Agu, M. [Ibaraki University, Ibaraki (Japan)


    An efficient calculation method of potential distribution in the presence of an embedded body in multi-layer earth has been proposed by expanding the method of image with a consideration of multiple reflection between the ground surface and each underground boundary. For this method, when solving boundary integral equation with the potential of embedded body surface as only one unknown, i.e., when obtaining discretization equation, ordinary boundary element program developed for analyzing the finite closed region can be used. As an example, numerical calculation was conducted for the two-layer earth. The analysis expression of potential distribution in the case of the certain embedded body in two-layer earth has never published. Accordingly, the calculated results were compared with those by the integral equation method. As a result, it was concluded that the primary potential obtained from the present method agreed well with that obtained from the integral equation method. However, there was a disregarded difference in the secondary potential. For confirming the effectiveness, it was necessary to compare with another numerical calculation method, such as finite element method. 5 refs., 5 figs.

  7. 两层损耗土壤媒质附近HEMP环境%HEMP Environment Over Two-layer Lossy Soil

    Institute of Scientific and Technical Information of China (English)

    孙蓓云; 周辉


    To understand the HEMP environment near ground is important for HEMP effects research of ground -base electrical system.The methods to calculate the reflection wave of plane wave and electromagnetic environment over two-layer lossy media are presented.The reflection wave and electromagnetic environment of HEMP over two-layered soil are calculated.The results indicate that there are two peaks in the reflection wave and the time of the second peak is determined by the thickness of the first layer soil.The tail-wave amplitude of x-direction HEMP environment is reduced than one layer's,and the tail-wave amplitude of z-direction is increased.%介绍了分层损耗媒质反射波的计算方法,计算了大地由一定厚度的干土和湿土构成时,x方向和z方向的HEMP反射波及地面附近电磁环境.计算结果表明x方向和z方向的反射波都有双峰,第2个峰出现的时间与第1层土壤的厚度有关;地面附近x方向HEMP环境场波尾的幅度较单层的会有下降,而z方向较单层的会有增加.

  8. On the Transformation Mechanism for Formulating a Multiproduct Two-Layer Supply Chain Network Design Problem as a Network Flow Model

    Directory of Open Access Journals (Sweden)

    Mi Gan


    Full Text Available The multiproduct two-layer supply chain is very common in various industries. In this paper, we introduce a possible modeling and algorithms to solve a multiproduct two-layer supply chain network design problem. The decisions involved are the DCs location and capacity design decision and the initial distribution planning decision. First we describe the problem and give a mixed integer programming (MIP model; such problem is NP-hard and it is not easy to reduce the complexity. Inspired by it, we develop a transformation mechanism of relaxing the fixed cost and adding some virtual nodes and arcs to the original network. Thus, a network flow problem (NFP corresponding to the original problem has been formulated. Given that we could solve the NFP as a minimal cost flow problem. The solution procedures and network simplex algorithm (INS are discussed. To verify the effectiveness and efficiency of the model and algorithms, the performance measure experimental has been conducted. The experiments and result showed that comparing with MIP model solved by genetic algorithm (GA and Benders, decomposition algorithm (BD the NFP model and INS are also effective and even more efficient for both small-scale and large-scale problems.

  9. A Two-Layered Diffusion Model Traces the Dynamics of Information Processing in the Valuation-and-Choice Circuit of Decision Making

    Directory of Open Access Journals (Sweden)

    Pietro Piu


    Full Text Available A circuit of evaluation and selection of the alternatives is considered a reliable model in neurobiology. The prominent contributions of the literature to this topic are reported. In this study, valuation and choice of a decisional process during Two-Alternative Forced-Choice (TAFC task are represented as a two-layered network of computational cells, where information accrual and processing progress in nonlinear diffusion dynamics. The evolution of the response-to-stimulus map is thus modeled by two linked diffusive modules (2LDM representing the neuronal populations involved in the valuation-and-decision circuit of decision making. Diffusion models are naturally appropriate for describing accumulation of evidence over the time. This allows the computation of the response times (RTs in valuation and choice, under the hypothesis of ex-Wald distribution. A nonlinear transfer function integrates the activities of the two layers. The input-output map based on the infomax principle makes the 2LDM consistent with the reinforcement learning approach. Results from simulated likelihood time series indicate that 2LDM may account for the activity-dependent modulatory component of effective connectivity between the neuronal populations. Rhythmic fluctuations of the estimate gain functions in the delta-beta bands also support the compatibility of 2LDM with the neurobiology of DM.

  10. Piezoelectric Resonator with Two Layers (United States)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)


    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  11. A Bio-Inspired Two-Layer Sensing Structure of Polypeptide and Multiple-Walled Carbon Nanotube to Sense Small Molecular Gases

    Directory of Open Access Journals (Sweden)

    Li-Chun Wang


    Full Text Available In this paper, we propose a bio-inspired, two-layer, multiple-walled carbon nanotube (MWCNT-polypeptide composite sensing device. The MWCNT serves as a responsive and conductive layer, and the nonselective polypeptide (40 mer coating the top of the MWCNT acts as a filter into which small molecular gases pass. Instead of using selective peptides to sense specific odorants, we propose using nonselective, peptide-based sensors to monitor various types of volatile organic compounds. In this study, depending on gas interaction and molecular sizes, the randomly selected polypeptide enabled the recognition of certain polar volatile chemical vapors, such as amines, and the improved discernment of low-concentration gases. The results of our investigation demonstrated that the polypeptide-coated sensors can detect ammonia at a level of several hundred ppm and barely responded to triethylamine.

  12. Convergence Improved Lax-Friedrichs Scheme Based Numerical Schemes and Their Applications in Solving the One-Layer and Two-Layer Shallow-Water Equations

    Directory of Open Access Journals (Sweden)

    Xinhua Lu


    Full Text Available The first-order Lax-Friedrichs (LF scheme is commonly used in conjunction with other schemes to achieve monotone and stable properties with lower numerical diffusion. Nevertheless, the LF scheme and the schemes devised based on it, for example, the first-order centered (FORCE and the slope-limited centered (SLIC schemes, cannot achieve a time-step-independence solution due to the excessive numerical diffusion at a small time step. In this work, two time-step-convergence improved schemes, the C-FORCE and C-SLIC schemes, are proposed to resolve this problem. The performance of the proposed schemes is validated in solving the one-layer and two-layer shallow-water equations, verifying their capabilities in attaining time-step-independence solutions and showing robustness of them in resolving discontinuities with high-resolution.

  13. Label-free logic modules and two-layer cascade based on stem-loop probes containing a G-quadruplex domain. (United States)

    Guo, Yahui; Cheng, Junjie; Wang, Jine; Zhou, Xiaodong; Hu, Jiming; Pei, Renjun


    A simple, versatile, and label-free DNA computing strategy was designed by using toehold-mediated strand displacement and stem-loop probes. A full set of logic gates (YES, NOT, OR, NAND, AND, INHIBIT, NOR, XOR, XNOR) and a two-layer logic cascade were constructed. The probes contain a G-quadruplex domain, which was blocked or unfolded through inputs initiating strand displacement and the obviously distinguishable light-up fluorescent signal of G-quadruplex/NMM complex was used as the output readout. The inputs are the disease-specific nucleotide sequences with potential for clinic diagnosis. The developed versatile computing system based on our label-free and modular strategy might be adapted in multi-target diagnosis through DNA hybridization and aptamer-target interaction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Influence of a fat layer on the near infrared spectra of human muscle: quantitative analysis based on two-layered Monte Carlo simulations and phantom experiments (United States)

    Yang, Ye; Soyemi, Olusola O.; Landry, Michelle R.; Soller, Babs R.


    The influence of fat thickness on the diffuse reflectance spectra of muscle in the near infrared (NIR) region is studied by Monte Carlo simulations of a two-layer structure and with phantom experiments. A polynomial relationship was established between the fat thickness and the detected diffuse reflectance. The influence of a range of optical coefficients (absorption and reduced scattering) for fat and muscle over the known range of human physiological values was also investigated. Subject-to-subject variation in the fat optical coefficients and thickness can be ignored if the fat thickness is less than 5 mm. A method was proposed to correct the fat thickness influence. c2005 Optical Society of America.

  15. Solitons, Bäcklund transformation and Lax pair for a generalized variable-coefficient Boussinesq system in the two-layered fluid flow (United States)

    Zhao, Xue-Hui; Tian, Bo; Chai, Jun; Wu, Yu-Xiao; Guo, Yong-Jiang


    Under investigation in this paper is a generalized variable-coefficient Boussinesq system, which describes the propagation of the shallow water waves in the two-layered fluid flow. Bilinear forms, Bäcklund transformation and Lax pair are derived by virtue of the Bell polynomials. Hirota method is applied to construct the one- and two-soliton solutions. Propagation and interaction of the solitons are illustrated graphically: kink- and bell-shape solitons are obtained; shapes of the solitons are affected by the variable coefficients α1, α3 and α4 during the propagation, kink- and anti-bell-shape solitons are obtained when α3 > 0, anti-kink- and bell-shape solitons are obtained when α3 < 0; Head-on interaction between the two bidirectional solitons, overtaking interaction between the two unidirectional solitons are presented; interactions between the two solitons are elastic.

  16. Two-layer hierarchical control solutions for traffic signal%面向交通信号的两层递阶控制解决方案

    Institute of Scientific and Technical Information of China (English)

    戈军; 周莲英


    针对现有交通信号控制系统的诸多不足,提出了一种用于交通信号控制的两层递阶多Agent系统解决方案。通过将交通网络进行区域划分,利用底层Agent控制各交叉口,顶层Agent控制区域,从而实现两层递阶控制。底层Agent采用经典Q学习同步学习最优策略,顶层Agent利用Tile Coding非凡的连续空间处理能力,实现Q学习的动作值函数逼近方法。仿真实验结果表明,该分层递阶控制不但提高了交通信号控制系统效率,而且也为大规模应用提供了很好的可伸缩解决方案。%In view of the existing deficiencies of traffic signal control system, this paper proposes two-layer hierarchical multi-Agent system solution for traffic signal control. Through regional division of the traffic network, it uses the bottom level Agent to control the intersection, the top level Agent to control areas, so as to achieve the two-layer hierarchical con-trol. The bottom level Agent uses the classical Q-learning to synchronize the optimal strategy, the top level Agent utilizes the special continuous space processing ability of Tile Coding to achieve Q learning of action value function approxima-tion method. The simulation test results show that, the hierarchical control not only improves the efficiency of traffic signal control system, but also provides a good scalable solution for large-scale applications.

  17. 胡椒碱在磷酸三丁酯修饰电极上的电化学行为研究%Investigation on Preconcentration and Electrochemical Behaviour of Piperine at TBP Modified Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    汪振辉; 张钱丽; 周漱萍


    研究了胡椒碱在磷酸三丁酯(TBP)修饰玻碳电极上的电化学行为.在pH4.6的Britton-Robison缓冲溶液中,胡椒碱在-1.40V(vs.SCE)处有一灵敏的极谱还原峰.吸附溶出峰电流与胡椒碱的量浓度在7.40×10-9~2.22×10-7mol/L范围内有良好的线性关系.富集6min检出限为 2.22×10-11mol/L.已用于天然胡椒中胡椒碱的测定.

  18. Desert shrub responses to experimental modification of precipitation seasonality and soil depth: relationship to the two-layer model and ecohydrological niche (United States)

    Germino, Matthew J.; Reinhardt, Keith


    1. Ecohydrological niches are important for understanding plant community responses to climate shifts, particularly in dry lands. According to the two-layer hypothesis, selective use of deep-soil water increases growth or persistence of woody species during warm and dry summer periods and thereby contributes to their coexistence with shallow-rooted herbs in dry ecosystems. The resource-pool hypothesis further suggests that shallow-soil water benefits growth of all plants while deep-soil water primarily enhances physiological maintenance and survival of woody species. Few studies have directly tested these by manipulating deep-soil water availability and observing the long-term outcomes. 2. We predicted that factors promoting infiltration and storage of water in deep soils, specifically greater winter precipitation and soil depth, would enhance Artemisia tridentata (big sagebrush) in cold, winter-wet/summer-dry desert. Sagebrush responses to 20 years of winter irrigation were compared to summer- or no irrigation, on plots having relatively deep or shallow soils (2 m vs. 1 m depths). 3. Winter irrigation increased sagebrush cover, and crown and canopy volumes, but not density (individuals/plot) compared to summer or no irrigation, on deep-soil plots. On shallow-soil plots, winter irrigation surprisingly decreased shrub cover and size, and summer irrigation had no effect. Furthermore, multiple regression suggested that the variations in growth were related (i) firstly to water in shallow soils (0-0.2 m) and secondly to deeper soils (> 1 m deep) and (ii) more by springtime than by midsummer soil water. Water-use efficiency increased considerably on shallow soils without irrigation and was lowest with winter irrigation. 4. Synthesis. Sagebrush was more responsive to the seasonal timing of precipitation than to total annual precipitation. Factors that enhanced deep-water storage (deeper soils plus more winter precipitation) led to increases in Artemisia tridentata that

  19. Estimation of available water capacity components of two-layered soils using crop model inversion: Effect of crop type and water regime (United States)

    Sreelash, K.; Buis, Samuel; Sekhar, M.; Ruiz, Laurent; Kumar Tomer, Sat; Guérif, Martine


    Characterization of the soil water reservoir is critical for understanding the interactions between crops and their environment and the impacts of land use and environmental changes on the hydrology of agricultural catchments especially in tropical context. Recent studies have shown that inversion of crop models is a powerful tool for retrieving information on root zone properties. Increasing availability of remotely sensed soil and vegetation observations makes it well suited for large scale applications. The potential of this methodology has however never been properly evaluated on extensive experimental datasets and previous studies suggested that the quality of estimation of soil hydraulic properties may vary depending on agro-environmental situations. The objective of this study was to evaluate this approach on an extensive field experiment. The dataset covered four crops (sunflower, sorghum, turmeric, maize) grown on different soils and several years in South India. The components of AWC (available water capacity) namely soil water content at field capacity and wilting point, and soil depth of two-layered soils were estimated by inversion of the crop model STICS with the GLUE (generalized likelihood uncertainty estimation) approach using observations of surface soil moisture (SSM; typically from 0 to 10 cm deep) and leaf area index (LAI), which are attainable from radar remote sensing in tropical regions with frequent cloudy conditions. The results showed that the quality of parameter estimation largely depends on the hydric regime and its interaction with crop type. A mean relative absolute error of 5% for field capacity of surface layer, 10% for field capacity of root zone, 15% for wilting point of surface layer and root zone, and 20% for soil depth can be obtained in favorable conditions. A few observations of SSM (during wet and dry soil moisture periods) and LAI (within water stress periods) were sufficient to significantly improve the estimation of AWC

  20. Optimal estimation reconstruction of the optical properties of a two-layered tissue phantom from time-resolved single-distance measurements (United States)

    Martelli, Fabrizio; Del Bianco, Samuele; Spinelli, Lorenzo; Cavalieri, Stefano; Di Ninni, Paola; Binzoni, Tiziano; Jelzow, Alexander; Macdonald, Rainer; Wabnitz, Heidrun


    In this work, we have tested the optimal estimation (OE) algorithm for the reconstruction of the optical properties of a two-layered liquid tissue phantom from time-resolved single-distance measurements. The OE allows a priori information, in particular on the range of variation of fit parameters, to be included. The purpose of the present investigations was to compare the performance of OE with the Levenberg-Marquardt method for a geometry and real experimental conditions typically used to reconstruct the optical properties of biological tissues such as muscle and brain. The absorption coefficient of the layers was varied in a range of values typical for biological tissues. The reconstructions performed demonstrate the substantial improvements achievable with the OE provided a priori information is available. We note the extreme reliability, robustness, and accuracy of the retrieved absorption coefficient of the second layer obtained with the OE that was found for up to six fit parameters, with an error in the retrieved values of less than 10%. A priori information on fit parameters and fixed forward model parameters clearly improves robustness and accuracy of the inversion procedure.

  1. Improving the prediction accuracy of residue solvent accessibility and real-value backbone torsion angles of proteins by guided-learning through a two-layer neural network. (United States)

    Faraggi, Eshel; Xue, Bin; Zhou, Yaoqi


    This article attempts to increase the prediction accuracy of residue solvent accessibility and real-value backbone torsion angles of proteins through improved learning. Most methods developed for improving the backpropagation algorithm of artificial neural networks are limited to small neural networks. Here, we introduce a guided-learning method suitable for networks of any size. The method employs a part of the weights for guiding and the other part for training and optimization. We demonstrate this technique by predicting residue solvent accessibility and real-value backbone torsion angles of proteins. In this application, the guiding factor is designed to satisfy the intuitive condition that for most residues, the contribution of a residue to the structural properties of another residue is smaller for greater separation in the protein-sequence distance between the two residues. We show that the guided-learning method makes a 2-4% reduction in 10-fold cross-validated mean absolute errors (MAE) for predicting residue solvent accessibility and backbone torsion angles, regardless of the size of database, the number of hidden layers and the size of input windows. This together with introduction of two-layer neural network with a bipolar activation function leads to a new method that has a MAE of 0.11 for residue solvent accessibility, 36 degrees for psi, and 22 degrees for phi. The method is available as a Real-SPINE 3.0 server in

  2. Integration of Ground and Multi-Resolution Satellite Data for Predicting the Water Balance of a Mediterranean Two-Layer Agro-Ecosystem

    Directory of Open Access Journals (Sweden)

    Piero Battista


    Full Text Available The estimation of site water budget is important in Mediterranean areas, where it represents a crucial factor affecting the quantity and quality of traditional crop production. This is particularly the case for spatially fragmented, multi-layer agricultural ecosystems such as olive groves, which are traditional cultivations of the Mediterranean basin. The current paper aims at demonstrating the effectiveness of spatialized meteorological data and remote sensing techniques to estimate the actual evapotranspiration (ETA and the soil water content (SWC of an olive orchard in Central Italy. The relatively small size of this orchard (about 0.1 ha and its two-layer structure (i.e., olive trees and grasses require the integration of remotely sensed data with different spatial and temporal resolutions (Terra-MODIS, Landsat 8-OLI and Ikonos. These data are used to drive a recently proposed water balance method (NDVI-Cws and predict ETA and then site SWC, which are assessed through comparison with sap flow and soil wetness measurements taken in 2013. The results obtained indicate the importance of integrating satellite imageries having different spatio-temporal properties in order to properly characterize the examined olive orchard. More generally, the experimental evidences support the possibility of using widely available remotely sensed and ancillary datasets for the operational estimation of ETA and SWC in olive tree cultivation systems.

  3. Production of Steel Casts in Two-Layer Moulds with Alkaline Binders Part 1. Backing sand with the alkaline inorganic binder RUDAL

    Directory of Open Access Journals (Sweden)

    M. Holtzer


    Full Text Available Steel casts in Z.N. POMET were produced in moulds made of the moulding sand Floster. This sand did not have good knocking outproperties, required a significant binder addition (4.5-5.0 parts by weight, and the casting surface quality gave rise to clients objections.Therefore a decision of implementing two-layer moulds, in which the facing sand would consist of the moulding sand with an alkalineorganic binder while the backing sand would be made of the moulding sand with an inorganic binder also of an alkaline character - wasundertaken. The fraction of this last binder in the moulding sand mass would be smaller than that of the binder used up to now (waterglass. The application of two moulding sands of the same chemical character (highly alkaline should facilitate the reclamation processand improve the obtained reclaimed material quality, due to which it would be possible to increase the reclaim fraction in the mouldingsand (up to now it was 50%. The results of the laboratory investigations of sands with the RUDAL binder are presented in the paper.

  4. MHD Heat Transfer in Two-Layered Flow of Conducting Fluids through a Channel Bounded by Two Parallel Porous Plates in a Rotating System (United States)

    Linga Raju, T.; Neela Rao, B.


    The paper aims to analyze the heat transfer aspects of a two-layered fluid flow in a horizontal channel under the action of an applied magnetic and electric fields, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a common constant pressure gradient in the channel bounded by two parallel porous insulating plates, one being stationary and the other one oscillatory. The fluids in the two regions are considered electrically conducting, and are assumed to be incompressible with variable properties, namely, different densities, viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperature. The governing partial differential equations are then reduced to the ordinary linear differential equations by using a two-term series. The temperature distributions in both fluid regions of the channel are derived analytically. The results are presented graphically to discuss the effect on the heat transfer characteristics and their dependence on the governing parameters, i.e., the Hartmann number, Taylor number, porous parameter, and ratios of the viscosities, heights, electrical and thermal conductivities. It is observed that, as the Coriolis forces become stronger, i.e., as the Taylor number increases, the temperature decreases in the two fluid regions. It is also seen that an increase in porous parameter diminishes the temperature distribution in both the regions.

  5. Physicochemical properties of hull-less barley fibre-rich fractions varying in particle size and their potential as functional ingredients in two-layer flat bread. (United States)

    Izydorczyk, M S; Chornick, T L; Paulley, F G; Edwards, N M; Dexter, J E


    The performance of barley fibre-rich fractions (FRF), as high dietary fibre ingredients, in two-layer flat bread was investigated. In addition, the effects of particle size reduction by pin milling on functional properties of FRF were studied. FRF enriched in non-starch polysaccharides (β-glucans and arabinoxylans) were obtained by roller milling of hull-less barley. Pin milling (PM) of FRF significantly reduced their particle size, slightly increased the solubility of β-glucans and arabinoxylans, and increased the viscosity of water slurries containing FRF. The addition of 20% of barley FRF to wheat flour significantly increased dough water absorption and weakened the dough properties, as indicated by farinograph mixing curves, but the FRF-enriched doughs exhibited good handling characteristics at the dividing and sheeting stages. The appearance, diameter, layer separation, crumb, and aroma of the FRF-enriched flat breads were comparable to that of the control. The PM of FRF did not significantly affect the dough handling or the quality characteristics of flat breads. The addition of 20% of barley FRF to wheat flour flat bread provided substantial health benefits by significantly increasing the total and soluble dietary fibre contents and by decreasing starch digestibility.

  6. Construction of Wave-free Potentials and Multipoles in a Two-layer Fluid Having Free-surface Boundary Condition with Higher-order Derivatives

    Institute of Scientific and Technical Information of China (English)

    Dilip Das


    There is a large class of problems in the field of fluid structure interaction where higher-order boundary conditions arise for a second-order partial differential equation. Various methods are being used to tackle these kind of mixed boundary-value problems associated with the Laplace’s equation (or Helmholtz equation) arising in the study of waves propagating through solids or fluids. One of the widely used methods in wave structure interaction is the multipole expansion method. This expansion involves a general combination of a regular wave, a wave source, a wave dipole and a regular wave-free part. The wave-free part can be further expanded in terms of wave-free multipoles which are termed as wave-free potentials. These are singular solutions of Laplace’s equation or two-dimensional Helmholz equation. Construction of these wave-free potentials and multipoles are presented here in a systematic manner for a number of situations such as two-dimensional non-oblique and oblique waves, three dimensional waves in two-layer fluid with free surface condition with higher order partial derivative are considered. In particular, these are obtained taking into account of the effect of the presence of surface tension at the free surface and also in the presence of an ice-cover modelled as a thin elastic plate. Also for limiting case, it can be shown that the multipoles and wave-free potential functions go over to the single layer multipoles and wave-free potential.

  7. A Two Layers Novel Low-Cost and Optimized Embedded Board Based on TMS320C6713 DSP and Spartan-3 FPGA

    Directory of Open Access Journals (Sweden)

    Bahram Rashidi


    Full Text Available This paper presents the design and implementation of a new low-cost and minimum embedded board based on TMS320C6713 (PYP 208-PIN (PQFP DSP and Spartan-3 (XCS400-4PQG208C FPGA in two layers with mount elements on two sides of the board. The proposed embedded board was developed satisfactorily for different applications such as data acquisition of sensor’s with serial port, control units, finite state machines, signal processing algorithms, navigation computing, Kalman filtering etc. Goal of the design was to implement as many as possible low-cost and minimum sizes of the board, also to receive input signals in a short time period and as real time. The board features are include: mount elements in two side of the board for minimization of the proposed board and also placed decoupling capacitors (by pass for the DSP and FPGA in bottom layer of board strictly below these two ICs because should be placed as close as possible to the power supply pins DSP and FPGA, GND polygon layer is used in total top layer and microcomputer ground for DSP & FPGA in bottom layer, use FPGA for two aim ones for implementation of glue logic total of board and interface between serial connectors, use three RS-232 serial port, one RS-422, and SPI serial port on FPGA, use MT48LC16M16A SDRAM-256MB(4*4MB*16, Am29LV400B Flash memory 4 Megabit (512 K x 8-Bit/256 K x 16-Bit and XCF02S configuration PROM. The size of the proposed embedded board is 11.1cm*17. 7cm so this board is optimized of aspect cost, performance, power, weight, and size.

  8. Assembly of 1D nanofibers into a 2D bi-layered composite nanofibrous film with different functionalities at the two layers via layer-by-layer electrospinning. (United States)

    Wang, Zijiao; Ma, Qianli; Dong, Xiangting; Li, Dan; Xi, Xue; Yu, Wensheng; Wang, Jinxian; Liu, Guixia


    A two-dimensional (2D) bi-layered composite nanofibrous film assembled by one-dimensional (1D) nanofibers with trifunctionality of electrical conduction, magnetism and photoluminescence has been successfully fabricated by layer-by-layer electrospinning. The composite film consists of a polyaniline (PANI)/Fe3O4 nanoparticle (NP)/polyacrylonitrile (PAN) tuned electrical-magnetic bifunctional layer on one side and a Tb(TTA)3(TPPO)2/polyvinylpyrrolidone (PVP) photoluminescent layer on the other side, and the two layers are tightly combined face-to-face together into the novel bi-layered composite film of trifunctionality. The brand-new film has totally different characteristics at the double layers. The electrical conductivity and magnetism of the electrical-magnetic bifunctional layer can be, respectively, tunable via modulating the PANI and Fe3O4 NP contents, and the highest electrical conductivity can reach up to the order of 10(-2) S cm(-1), and predominant intense green emission at 545 nm is obviously observed in the photoluminescent layer under the excitation of 357 nm single-wavelength ultraviolet light. More importantly, the luminescence intensity of the photoluminescent layer remains almost unaffected by the electrical-magnetic bifunctional layer because the photoluminescent materials have been successfully isolated from dark-colored PANI and Fe3O4 NPs. By comparing with the counterpart single-layered composite nanofibrous film, it is found that the bi-layered composite nanofibrous film has better performance. The novel bi-layered composite nanofibrous film with trifunctionality has potential in the fields of nanodevices, molecular electronics and biomedicine. Furthermore, the design conception and fabrication technique for the bi-layered multifunctional film provide a new and facile strategy towards other films of multifunctionality.

  9. Supervised Learning of Two-Layer Perceptron under the Existence of External Noise — Learning Curve of Boolean Functions of Two Variables in Tree-Like Architecture — (United States)

    Uezu, Tatsuya; Kiyokawa, Shuji


    We investigate the supervised batch learning of Boolean functions expressed by a two-layer perceptron with a tree-like structure. We adopt continuous weights (spherical model) and the Gibbs algorithm. We study the Parity and And machines and two types of noise, input and output noise, together with the noiseless case. We assume that only the teacher suffers from noise. By using the replica method, we derive the saddle point equations for order parameters under the replica symmetric (RS) ansatz. We study the critical value αC of the loading rate α above which the learning phase exists for cases with and without noise. We find that αC is nonzero for the Parity machine, while it is zero for the And machine. We derive the exponents barβ of order parameters expressed as (α - α C)bar{β} when α is near to αC. Furthermore, in the Parity machine, when noise exists, we find a spin glass solution, in which the overlap between the teacher and student vectors is zero but that between student vectors is nonzero. We perform Markov chain Monte Carlo simulations by simulated annealing and also by exchange Monte Carlo simulations in both machines. In the Parity machine, we study the de Almeida-Thouless stability, and by comparing theoretical and numerical results, we find that there exist parameter regions where the RS solution is unstable, and that the spin glass solution is metastable or unstable. We also study asymptotic learning behavior for large α and derive the exponents hat{β } of order parameters expressed as α - hat{β } when α is large in both machines. By simulated annealing simulations, we confirm these results and conclude that learning takes place for the input noise case with any noise amplitude and for the output noise case when the probability that the teacher's output is reversed is less than one-half.

  10. Long-term effects of dietary supplementation with an essential oil mixture on the growth and laying performance of two layer strains

    Directory of Open Access Journals (Sweden)

    Abdullah U. Çatli


    Full Text Available One thousand two hundred 1-day-old Lohmann LSL white and Lohmann Brown layer chickens were fed diets supplemented with either an antibiotic growth promoter (AGP or an herbal essential oil mixture (EOM till 58 wk of age to reveal the long-term effects of those additives on growth, performance and wholesome egg quality parameters. The study was arranged in a 2x3 factorial design with two layer strains and three feed additive regimens. Thus, the layer birds of both strains were randomly assigned to the three dietary treatments, i.e., standard basal diet (control, control with AGP (specifically, avilamycin, 10 mg/kg diet and control with EOM (24 mg/kg diet. The data regarding egg production were recorded between 22 to 58 weeks of age. Neither the dietary treatments nor the bird strain influenced the body weight and mortality of the birds in both the growing and laying period. AGP or EOM supplementation to the laying hen diet significantly increased the egg production rate and egg weight as compared to the control  diet alone, but egg mass output, feed consumption, and feed conversion ratio were not effected  by the dietary treatments. Neither dietary treatment created any statistically significantly differences in egg quality parameters with the exception of Haugh unit. The research findings have confirmed the beneficial effects of supplementation with feed-grade EOM on the laying rate and egg weight of both white and brown layers. Indeed, EOM, being a novel feed additive natural origin, proved to be as efficacious as AGP in promoting egg yield.

  11. Unsteady two-layered fluid flow of conducting fluids in a channel between parallel porous plates under transverse magnetic field in a rotating system

    Directory of Open Access Journals (Sweden)

    Linga Raju T.


    Full Text Available An unsteady MHD two-layered fluid flow of electrically conducting fluids in a horizontal channel bounded by two parallel porous plates under the influence of a transversely applied uniform strong magnetic field in a rotating system is analyzed. The flow is driven by a common constant pressure gradient in a channel bounded by two parallel porous plates, one being stationary and the other oscillatory. The two fluids are assumed to be incompressible, electrically conducting with different viscosities and electrical conductivities. The governing partial differential equations are reduced to the linear ordinary differential equations using two-term series. The resulting equations are solved analytically to obtain exact solutions for the velocity distributions (primary and secondary in the two regions respectively, by assuming their solutions as a combination of both the steady state and time dependent components of the solutions. Numerical values of the velocity distributions are computed for different sets of values of the governing parameters involved in the study and their corresponding profiles are also plotted. The details of the flow characteristics and their dependence on the governing parameters involved, such as the Hartmann number, Taylor number, porous parameter, ratio of the viscosities, electrical conductivities and heights are discussed. Also an observation is made how the velocity distributions vary with the rotating hydromagnetic interaction in the case of steady and unsteady flow motions. The primary velocity distributions in the two regions are seen to decrease with an increase in the Taylor number, but an increase in the Taylor number causes a rise in secondary velocity distributions. It is found that an increase in the porous parameter decreases both the primary and secondary velocity distributions in the two regions.


    Directory of Open Access Journals (Sweden)

    A. V. Chernyshev


    Full Text Available In carrying out eddy current thickness measurement of two-layer conductive objects one from the interfering factors is the presence of variations in the value of the electrical conductivity of the material of the upper layer (coating when moving from point to point on the surface of object of control or when passing from one object of control to another. The aim of this work is to evaluate the accuracy of determining the thickness of the conductive coating disposed on a conducting ferromagnetic basis, using the phase method of eddy current testing. The reason of the error is variation of the electrical conductivity of the material of coating.Determination of the error is based on calculations using known analytical expressions for the loop with current of sinusoidal form arranged over the infinite half space with a covering as a thin layer. Selected in calculating electromagnetic parameters of coating and substrate approximately correspond to the case -chromium layer on a nickel base. Calculations are performed for different frequencies of current passed through coil.It is shown that at reduction of frequency of the current passes through the coil the error is reduced. The value of the lowest possible operating frequency of the excitation current is determined by the condition of absence influence on the phase introduced into the superimposed transducer emf variations in the thickness of the basis.To reduce the indicated error it is proposed to determine, on the basis of phase method at a relatively high frequency transducer current excitation, conductivity of the material of coating. After this, at a low frequency excitation current and using phase method, the coating thickness is determined, taking into consideration the previously determined value of the conductivity of coating. Also discussed ways to improve the accuracy of phase measurements in the MHz region of the excitation current frequency. 

  13. Using stable water isotopes in a two-layer soil moisture conceptual framework to understand transpiration dynamics in a semiarid shrubland (United States)

    Szutu, D. J.; Papuga, S. A.; Wehr, R.


    Semiarid shrublands and other dryland ecosystems are highly sensitive to precipitation pulses. Because the frequency and magnitude of precipitation events have been projected to change for these ecosystems, the nature of these pulses and how they are distributed as moisture in the soil profile are also expected to change. Previous research has suggested that transpiration dynamics in drylands are associated with deep soil moisture, which accumulates after large rainfall events. Because transpiration is the productive component of evapotranspiration in that it is water used toward biomass accumulation, a hypothetical decrease in large rainfall events would have major consequences for the health and functioning of dryland ecosystems. Furthermore, as drylands account for nearly 40% of terrestrial biomes, these cascading changes have the potential to impact global water and carbon budgets. Still, in pulse-dependent dryland ecosystems, the relative contribution of transpiration to evapotranspiration and the temporal dynamics of this contribution are not well understood. The objective of this research is to better characterize the temporal dynamics of transpiration in dryland ecosystems. We present the relative contribution of transpiration to evapotranspiration over the course of a year from eddy covariance and sap flow measurements taken at a creosotebush-dominated shrubland ecosystem in southern Arizona. We analyze soil moisture and stable water isotopes within the context of a two-layer soil moisture conceptual framework in an attempt to identify the source water for transpiration. We use these results to explain the temporal dynamics of transpiration in this semiarid shrubland. Finally, we put our results in the context of regional climate projections to suggest how this dryland ecosystem might be impacted in the future. We expect our study will contribute to understanding where precipitation pulses are distributed in the soil moisture profile and when these pulses

  14. 异经多纬双层织物的生产%Production of Two-layer Fabric with Different Warp and Multiple Weft

    Institute of Scientific and Technical Information of China (English)

    郭凯军; 刘渊民; 邓红卫


    Design and key points in producing two-layer fabric with different warp and multiple wefts were discussed. The differences between warp and weft were larger,the production difficulties were larger than that of traditional fabric,two kinds of warp tension should be controlled well in warping. Slub yarn was dyed in sizing process to ensure correct reed-in. In weaving process, weft-inserting pressure of main nozzle was adjusted properly, loom tension was increased properly, loom processing was optimized rationally to prevent weft movement in back and weft shrinkage et al After adjusting processing, loom efficiency can be reached above 87% , storage rate of first-class product can be reached above 99. 8% , design and production demands can be reached.%探讨异经多纬双层织物的设计与生产技术要点.针对织物经纬纱差异、生产难度比传统织物大的特点,整经工序要控制好两种经纱的张力;浆纱时对其中的竹节纱进行上色,确保穿筘工序按工艺排列正确穿筘;织造工序合理调节主喷嘴引纬气压,适当增加上机张力,合理调试上机工艺,防止反面纬纱游移、纬缩等疵点造成染整后布面风格与质量变差.通过对工艺进行调整后,织机效率达到87%以上,产品入库一等品率达99.8%以上,满足了设计及生产要求.

  15. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts (United States)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir


    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  16. Radiation chemical behavior of actinides in extraction systems. IV. Interaction of Pu(IV) with H/sub 3/PO/sub 4/ in the system 30% TBP + n-dodecane

    Energy Technology Data Exchange (ETDEWEB)

    Fedoseev, D.A.; Boikova, I.A.; Milovanova, A.S.; Fedotov, S.N.; Naumov, M.A.; Vladimirova, M.V.


    Spectrophotometric, radiometric (..gamma..-spectrophotometric), and elemental analyses were used to determine the composition, solubility, and concentration stability constant K of complexes of Pu(IV) with H/sub 3/PO/sub 4/ in the system 30% TBP + n-dodecane containing 0.45 M HNO/sub 3/. For a Pu(IV) concentration of approx. 1 x 10/sup -2/ M and a molar concentration ratio of H/sub 3/PO/sub 4/ and Pu(IV) of less than or equal to 2.5 the sparingly soluble (1.8 x 10/sup -3/ M) complex Pu(HPO/sub 4/)/sub 2/ is formed. In the range of H/sub 3/PO/sub 4/ concentrations (C/sub L//sup 0/) from 5 x 10/sup -3/ to 3.0 x 10/sup -2/ M the value of K does not depend on C/sub L//sup 0/ and is (1.8 +/- 0.6) x 10/sup 5/ liter/sup 2//mole/sup 2/. The results are discussed and compared with the interaction of Pu(IV) with DBPA and MBPA in aqueous and organic solutions.

  17. 磷酸二(2-乙基己基)酯-磷酸三丁酯-异辛烷反胶束萃取卡那霉素的研究%Study on Extraction of Kanamycin with HDEHP-TBP-Isooctane Reverse Micelles

    Institute of Scientific and Technical Information of China (English)

    李夏兰; 翁连进; 陈培钦; 蔡婀娜


    目的 研究反胶束提取氨基糖苷类抗生素的可能性,寻求高效且环境友好的氨基糖苷类抗生素的生产工艺.方法 将磷酸二(2-乙基己基)酯(HDEHP)、磷酸三丁酯(TBP)、异辛烷形成反胶束,与卡那霉素溶液或发酵滤液混合、振荡、离心.结果 反胶束萃取率与水相pH值、盐浓度密切相关.当KCl浓度为0.05 mol·L-1,萃取前水相pH为10,HDEHP浓度为1 mol·L-1时,HDEHP-TBP-异辛烷反胶束萃取发酵滤液的萃取率为88.6%.结论 HDEHP-TBP-异辛烷反胶束萃取反胶束是可行的.

  18. Optimized analysis and experimental study for two-layer contact of crystalline silicon solar cells%晶体硅太阳电池双层电极优化分析与实验研究

    Institute of Scientific and Technical Information of China (English)

    李涛; 周春兰; 刘振刚; 赵雷; 李海玲; 刁宏伟; 王文静


    相对于单层电极结构,优化的前表面双层电极能够明显减小功率损失,改善晶体硅太阳电池的电学特性.本文对晶体硅太阳电池的双层电极进行了优化分析和实验研究.通过扫描电子显微镜观测将双层电极的截面抽象为更接近于实际的半椭圆型,建立了太阳电池前表面的双层电极模型,理论分析了双层电极的电学损失和光学损失.结合丝网印刷后光诱导电镀太阳电池的实验,得到了理论和实验上的最优化光诱导电镀增厚电极厚度与丝网印刷电极宽度的关系.所得到的理论和实验结果符合良好.由于并不涉及电极制备的具体技术,双层电极理论模型普遍适用于多种类型的双层电极结构.%Compared with single-layer contact,optimized two-layer contact of front side could diminish power losses distinctly and improve the electrical performance of crystalline silicon solar cell.In this paper,the optimized analysis and experimental study for two-layer contact of crystalline silicon solar cell are carried out.The model of two-layer contact is established by abstracting the crosssection of two-layer contact into semi-elliptical shape closer to the realistic situation according to the SEM observation.The electrical losses and the optical losses of two-layer contact are analyzed in theory.In combination with experimental screen-printed contact thickened by light-induced electroplating solar cell,the relationship between the optimum thickening contact thickness by light-induced electroplating and the screen-printed contact width is achieved in theory and experiment.The corresponding theory and experimental results are in good agreement with each other.Due to involving no concrete technology of contact preparation,the theoretical model of two-layer contact is generally appticable for many types of two-layer contact structures in consequence.

  19. 面向个性化推荐的两层混合图模型%Hybrid Graph Model with Two Layers for Personalized Recommendation

    Institute of Scientific and Technical Information of China (English)

    张少中; 陈德人


    A hybrid graph model for personalized recom-mendation,which is based on small world network and Bayesian network,is presented.The hybrid graph model has two-layers.The bottom level means user's layer and the upper one means merchandise's layer.The user's layer is an undirected arcs graph,which describes the relation of the user's nodes by small world network.The undirected arcs inside the connected nodes of user's layer mean the similarity of the preference of users.These arcs are weighted by relational strength.The weight represents node's similarity or link's strength and intensity.Nodes in the same group are more similar to each other or more strongly connected.Users in a produce to others.It is connected by directed links,which means an implicated definition among merchandises,a user that purchase certain merchandise also tends to purchase another.The properties and content of merchandise can be used to show the similarity of the merchandise.The relations between user's layer and merchandise's layer are connected by directed links.The start nede of the directed links is a user node in user's layer belonging to some node group,which is gained by small world network.The end node of links is the node of some merchandise of the merchandise's layer.The directed links between the user's layer and the merchandise's layer are connected based on trade information of users.The strength of the relation between users and merchandises can be denoted by the probability parameter.The probability parameter shows a possibility of some users selecting for some merchandises. Firstly,algorithms for users clustering and for analysis of new user interest are presented to construct a hybrid graph model.Two important characteristic parameters,which are in small-world network,are introduced.These are characteristic path length and clustering coefficient.New user interest analysis is to judge which clustering group is the best match by calculating the distance of the new user node to

  20. Direct determination of uranium and co-extracted elements in the organic phases (D2EHPA/TOPO, TBP, TDA) in kerosene by TXRF technique. (United States)

    Stas, J; Khuder, A; Karjou, J


    The total reflection X-ray fluorescence (TXRF) spectrometry was used for direct determination of uranium concentration in the organic phase di-(2-ethyl hexyl) phosphoric acid and trioctyl phosphine oxide (D(2)EHPA-TOPO)/kerosene, which resulted from first and second cycles of uranium extraction from wet-process phosphoric acid. The TXRF measurements were performed using gallium as an internal standard. A linear relationship between relative intensity of uranium vs. gallium (I(U)/S(Ga)) against uranium concentration has been obtained. Four calibration curves, 0-5, 5-100, 100-1000 and 1000-7000 microgmL(-1), according to uranium concentration in the studied samples, were constructed. The detection limit was found to be 0.15 microgmL(-1). The effect of D(2)EHPA and TOPO concentration in kerosene on uranium determination was considered. The TXRF spectrometry was also applied for the multi-elemental analysis of the co-extracted impurities with uranium, such as (Fe, Ni, Cu and Zn) in the organic phase, and four calibration curves, 0-500 microgmL(-1) Fe, 0-20 microgmL(-1) Ni, 0-10 microgmL(-1) Cu and 0-20 microgmL(-1) Zn, according to Fe, Ni, Cu and Zn concentration in the studied samples were performed, respectively, using gallium as an internal standard. The obtained results using direct TXRF analysis method were in a very good agreement with those obtained by fluorometry method, which is suitable for aqueous solutions after stripping of uranium from the organic phase by 1M Na(2)CO(3).

  1. Extraction of rare earth elements from their oxides using organophosphorus reagent complexes with HNO_3 and H_2O in supercritical CO_2

    Institute of Scientific and Technical Information of China (English)

    段五华; 曹丕佳; 朱永(贝睿)


    Direct extraction of metals from solids with complexing agents in supercritical CO2(SC-CO2) has recently attracted interests in separation,purification,recovery,and analysis of metals.In the present study,the static/dynamic extraction of rare earth elements(Nd,Ce) from their oxides(Nd2O3,CeO2) with organophosphorus complexes with HNO3 and H2O in SC-CO2 was investigated.The static extraction efficiency of Nd from Nd2O3 with the tri-n-butylphosphate(TBP)-HNO3 complex could reach 95% under optimized experiment...

  2. Analysis of the Deformability of Two-Layer Materials AZ31/Eutectic / Analiza Możliwości Odkształcania Plastycznego Materiału Dwuwarstwowego AZ31/Eutektyka

    Directory of Open Access Journals (Sweden)

    Mola R.


    Full Text Available The paper present the results of physical simulation of the deformation of the two-layered AZ31/eutectic material using the Gleeble 3800 metallurgical processes simulator. The eutectic layer was produced on the AZ31 substrate using thermochemical treatment. The specimens of AZ31 alloy were heat treated in contact with aluminium powder at 445°C in a vacuum furnace. Depending on the heating time, Al-enriched surface layers with a thickness of 400, 700 and 1100 μm were fabricated on a substrate which was characterized by an eutectic structure composed of the Mg17Al12 phase and a solid solution of aluminium in magnesium. In the study, physical simulation of the fabricated two-layered specimens with a varying thickness of the eutectic layer were deformed using the plane strain compression test at various values of strain rates. The testing results have revealed that it is possible to deform the two-layered AZ31/eutectic material at low strain rates and small deformation values.

  3. Three-dimensional random resistor-network model for solid oxide fuel cell composite electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Abbaspour, Ali [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6 (Canada); Luo Jingli, E-mail: jingli.luo@ualberta.c [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6 (Canada); Nandakumar, K. [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA (United States)


    A three-dimensional reconstruction of solid oxide fuel cell (SOFC) composite electrodes was developed to evaluate the performance and further investigate the effect of microstructure on the performance of SOFC electrodes. Porosity of the electrode is controlled by adding pore former particles (spheres) to the electrode and ignoring them in analysis step. To enhance connectivity between particles and increase the length of triple-phase boundary (TPB), sintering process is mimicked by enlarging particles to certain degree after settling them inside the packing. Geometrical characteristics such as length of TBP and active contact area as well as porosity can easily be calculated using the current model. Electrochemical process is simulated using resistor-network model and complete Butler-Volmer equation is used to deal with charge transfer process on TBP. The model shows that TPBs are not uniformly distributed across the electrode and location of TPBs as well as amount of electrochemical reaction is not uniform. Effects of electrode thickness, particle size ratio, electron and ion conductor conductivities and rate of electrochemical reaction on overall electrochemical performance of electrode are investigated.

  4. Saliva of TBP digests double stranded RNAs (United States)

    The tarnished plant bug (TPB), Lygus lineolaris, is a generalist pest of many crops including cotton, strawberries, and alfalfa. While studying gene expression and gene knockdown through RNA interference, my lab was frustrated by an observation. We were unable to replicate knock down effects observe...

  5. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell. (United States)

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud


    Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition.

  6. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell (United States)

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud


    Zinc zirconate (ZnZrO3) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO2) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO3 as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff = 56%) compared to ZnO working electrode (ff = 40%) under the same condition.

  7. Structural characterization of tellurite glasses doped with transition metal oxides using Raman spectra and ab initio calculations (United States)

    Mohamed, Tarek A.; Shaltout, I.; Al Yahyaei, K. M.


    Systems of iron tellurite glasses were prepared by melt quenching with compositions of [85%TeO 2 + 5%Fe 2O 3 + 10%TMO], where transition metal oxides (TMO) are TiO 2, V 2O 5, MnO, CoO, NiO and CuO. Furthermore, the main structural units of these samples have been characterized by means of Raman spectra (150-1200 cm -1) as well as wavenumber predictions by means of Gaussian 98 ab initio calculations for the proposed site symmetries of TeO 44- triagonal bipyramid ( C2v) and Te 2O 76- bridged tetrahedra ( Cs and C1). Aided by normal coordinate analysis, calculated vibrational frequencies, Raman scattering activities, force constants in internal coordinates and potential energy distributions (PEDs), revised vibrational assignments for the fundamental modes have been proposed. The main structural features are correlated to the dominant units of triagonal bipyramid (tbp) or bridged tetrahedral (TeO 3+1 binds to TeO 3 through TeOTe bridge; corner sharing). Moreover, the Raman spectra of the investigated tellurites reflect a structural change from tbp (coordination number is four) to triagonal pyramidal (coordination number is three).

  8. Feynman Algorithm Implementation for Comparison with Euler in a Uniform Elastic Two-Layer 2D and 3D Object Dynamic Deformation Framework in OpenGL with GUI

    CERN Document Server

    Song, Miao


    We implement for comparative purposes the Feynman algorithm within a C++-based framework for two-layer uniform facet elastic object for real-time softbody simulation based on physics modeling methods. To facilitate the comparison, we implement initial timing measurements on the same hardware against that of Euler integrator in the softbody framework by varying different algorithm parameters. Due to a relatively large number of such variations we implement a GLUI-based user-interface to allow for much more finer control over the simulation process at real-time, which was lacking completely in the previous versions of the framework. We show our currents results based on the enhanced framework. The two-layered elastic object consists of inner and outer elastic mass-spring surfaces and compressible internal pressure. The density of the inner layer can be set differently from the density of the outer layer; the motion of the inner layer can be opposite to the motion of the outer layer. These special features, whic...

  9. Progress in Polyimide Films for Two-Layer Type Flexible Copper Clad Laminate%二层型挠性覆铜板用聚酰亚胺的研究进展

    Institute of Scientific and Technical Information of China (English)

    刁恩晓; 李帆; 舒适; 肖炳瑞; 黄永发; 王平; 刘峰


    The fast development of electronic industry puts forward higher requirements for the property of flexible copper clad laminate (FCCL). The research progress of two-layer type FCCL, which using polyimide film as substract, was reviewed from improving the adhesive property, dielectric property and heat resistance, and the research directions of two-layer type FCCL were proposed.%电子行业的快速发展对二层型挠性覆铜板的性能提出了更高的要求,针对以聚酰亚胺薄膜为基底材料的二层型挠性覆铜板,分别从改善粘结性能、介电性能和耐热性能3个方面综述了二层型挠性覆铜板的研究进展,并展望了二层型挠性覆铜板的研究方向。

  10. The phosphine oxides Cyanex 921 and Cyanex 923 as carriers for facilitated transport of chromium (VI)-chloride aqueous solutions. (United States)

    Alguacil, Francisco José; López-Delgado, Aurora; Alonso, Manuel; Sastre, Ana Maria


    The behaviour of the phosphine oxides Cyanex 921 and Cyanex 923 in the facilitated transport of chromium (VI) from chloride solutions is described. Transport is studied as a function of several variables such as stirring speeds of the aqueous phases, membrane phase diluent, hydrochloric acid concentration in the source phase and chromium and carrier concentrations. The separation of chromium (VI) from other metals presented in the source phase as well as the behaviour of phosphine oxides with respect to other neutral organophosphorous derivatives (tri-n-butylphosphate (TBP) and dibutyl butylphosphonate (DBBP)) are also investigated. Moreover, by using hydrazine sulphate in the receiving phase, Cr(VI) is immediately reduced to the less toxic Cr(III).

  11. Treatment of waste by the Molten Salt Oxidation process at the Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Crosley, S.M.; Lorenzo, D.K.; Van Cleve, J.E. [Oak Ridge National Lab., TN (United States); Gay, R.L.; Barclay, K.M.; Newcomb, J.C.; Yosim, S.J.


    The Molten Salt Oxidation (MSO) process has been under development by Rockwell International to treat hazardous, radioactive, and mixed waste. Testing of the system was done on a number of wastes to demonstrate the technical feasibility of the process. This testing included simulated intermediate level waste (ILW) from the Oak Ridge National Laboratory. The intermediate level waste stream consisted of a slurry of concentrated aqueous solutions of sodium hydroxide and sodium nitrate, with a small amount of miscellaneous combustible components (PVC, TBP, kerosene, and ion exchange resins). The purpose of these tests was to evaluate the destruction of the organics, evaporation of the water, and conversion of the hazardous salts (hydroxide and nitrate) to non-hazardous sodium carbonate. Results of the tests are discussed and analyzed, and the possibilities of applying the MSO process to different waste streams at ORNL in the future are explored.

  12. 尼莫地平双层渗透泵片的制备及其体外释放度考察%Preparation and in Vitro Release of Nimodipine Two-layer Osmotic Pump Tablets

    Institute of Scientific and Technical Information of China (English)

    张冠男; 白靖; 曹德英


    目的:制备尼莫地平双层渗透泵控释片,并考察其体外释放度.方法:以体外累积释放度作为评价指标,以含药层助悬剂聚氧化乙烯(PEO)200000的用量、促渗剂氯化钠的用量、致孔剂聚乙二醇(PEG)2000的含量及包衣增重为考察因素,采用正交设计优化尼莫地平双层渗透泵控释片的处方;参照《中国药典》释放度测定法第二法测定其体外释放度.结果:最优处方为含药层PEO 200000 80 mg,氯化钠10 mg,助推层PEO 5000000 40 mg,PEG 2000用量8%,包衣增重8%.所制片剂释药速率恒定,12 h的体外累积释放度达90%以上.结论:尼莫地平双层渗透泵片工艺稳定,体外释放行为在12 h内具有明显的零级释放特征(r=0.990 3),达到了控释要求.%OBJECTIVE: To prepare Nimodipine two-layer osomatic pump tablets and to study the in vitro release of it. METHODS: The preparation formula of Nimodipine two-layer osomatic pump tablets was optimized by orthogonal design with accumulative release rate as index using the amount of PEO 200000 and osmotic promoter NaCl, the content of PEG 2000 and the weight growth of coating membrane as factors. The in vitro release of preparation was determined in accordance with the method stated in Chinese Pharmacopeia. RESULTS: The optimal formula was as follows: PEO 200000 in drug-containing layer of 80 mg, NaCl of 10 mg, PEO 5000000 in push layer of 40 mg, PEG 2000 of 8%, weight gain for coating membrane of 8%. The release rate was constant, the accumulative release rate was above 90% in 12 h. CONCLUSION: The preparation of Nimodipine two-layer osomatic pump tablets is stable, and the in vitro drug release shows excellent zero-release profile within 12 h (r=0.990 3), and in line with controlled requirements.

  13. Two-dimensional heterospectral correlation analysis of the redox-induced conformational transition in cytochrome c using surface-enhanced Raman and infrared absorption spectroscopies on a two-layer gold surface. (United States)

    Zou, Changji; Larisika, Melanie; Nagy, Gabor; Srajer, Johannes; Oostenbrink, Chris; Chen, Xiaodong; Knoll, Wolfgang; Liedberg, Bo; Nowak, Christoph


    The heme protein cytochrome c adsorbed to a two-layer gold surface modified with a self-assembled monolayer of 2-mercaptoethanol was analyzed using a two-dimensional (2D) heterospectral correlation analysis that combined surface-enhanced infrared absorption spectroscopy (SEIRAS) and surface-enhanced Raman spectroscopy (SERS). Stepwise increasing electric potentials were applied to alter the redox state of the protein and to induce conformational changes within the protein backbone. We demonstrate herein that 2D heterospectral correlation analysis is a particularly suitable and useful technique for the study of heme-containing proteins as the two spectroscopies address different portions of the protein. Thus, by correlating SERS and SEIRAS data in a 2D plot, we can obtain a deeper understanding of the conformational changes occurring at the redox center and in the supporting protein backbone during the electron transfer process. The correlation analyses are complemented by molecular dynamics calculations to explore the intramolecular interactions.

  14. Web实时环境两级过滤中文文本内容自学习算法%Self-Study Algorithm for Filtering Chinese Text Content through Two Layers in Web Real-Time Environment

    Institute of Scientific and Technical Information of China (English)

    段磊; 唐常杰; 左劫; 彭京; 刘婷婷; 苟驰


    用户在互联网发布信息的自由性对Web信息内容过滤提出新的挑战.为此,给出一种自学习的两级内容过滤算法SAFE (self-study algorithm of filtering Chinese text content).SAFE以数据流的方式处理文本,并根据Apriori性质,在不依赖词典的情况下,通过挖掘关键字和关键词实现对文档的两级内容过滤.利用真实世界Web文档验证了SAFE的有效性,实验表明对给定的主题进行文本内容过滤,SAFE的查全率达到93.75%以上,查准率达到100%,执行时间能够满足Web应用的实时性要求.%The publishing freedom of users on Internet poses new challenges in Web content filtering. This paper presents a self-study algorithm, called SAFE (self-study algorithm of filtering Chinese text content), for Chinese content filtering through two layers. It processes texts in the form of data stream. Based on Apriori property, SAFE filters Chinese text content through two layers by mining key characters and keywords without manual dictionary. The performance research of SAFE on the real-world data shows that for the given theme, the recall of SAFE is greater than 93.75% and the precision is 100%. The runtime of SAFE satisfies the real-time requirement of Web applications.

  15. Computational fluid dynamics analysis of core bypass flow and crossflow in a prismatic very high temperature gas-cooled nuclear reactor based on a two-layer block model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huhu, E-mail: [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Dominguez-Ontiveros, Elvis, E-mail: [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Hassan, Yassin A., E-mail: [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Department of Mechanical Engineering, Texas A and M University, 3123 TAMU, College Station, TX 77840 (United States)


    Highlights: • A CFD model was built based on a two-layer block experimental facility at Texas A and M University. • The coolant characterizations within the uniform and wedge-shaped crossflow gap regions were investigated. • The influence on the coolant distribution from the bypass flow gap width was studied. • Discretization and iterative errors involved in the simulations were quantified. - Abstract: The very high temperature gas-cooled nuclear reactor (VHTR) has been designated as one of the promising reactors that will serve for the Next Generation (Generation IV) Nuclear Plant. For a prismatic VHTR core, the bypass flow and crossflow phenomena are important design considerations. To investigate the coolant distribution in the reactor core based on the two-layer block facility built at Texas A and M University, a three-dimensional steady-state CFD analysis was performed using the commercial code STAR-CCM+ v6.04. Results from this work serve as a guideline and validating source for the related experiments. A grid independence study was conducted to quantify related errors in the simulations. The simulation results show that the bypass flow fraction was not a strong function of the Reynolds number. The presence of the crossflow gap had a significant effect on the distribution of the coolant in the core. Uniform and wedge-shape crossflow gaps were studied. It was found that a significant secondary flow in the crossflow gap region moved from the bypass flow gap toward coolant holes, which resulted in up to a 28% reduction of the coolant mass flow rate in the bypass flow gap.


    Directory of Open Access Journals (Sweden)

    Andreev Vladimir Igorevich


    Full Text Available In the paper, the authors provide the results of analysis of a real construction facility performed with the help of a model of a two-layer beam of variable rigidity resting on the elastic bedding. The bottom layer of a two-layer beam simulates the foundation, the upper payer stands for the structure, and the weight of each layer is taken into consideration. The characteristics of the upper layer change alongside its length. Analytical and numerical methods of calculation were applied to solve this problem. The analytical solution is based on the method of initial parameters and backed by the practical data extracted from "Frame and Towerlike Buildings: Mattress Foundation Design Manual". According to the above manual, whenever the length-to-width ratio of a building exceeds 1.5, one-dimensional pattern composed of a composite beam resting on the elastic bedding may be used. The beam is divided into several sections, and deflection of each section is identified. It is equal to the settlements of the bedding surface. The rigidity change alongside the length of each section is assumed to be permanent, i.e. the beam is considered as the one that demonstrates its piecewise-constant rigidity. The following conclusion can be made on the basis of the calculations performed by the authors: the calculation of the «structure-foundation-bedding» system may require a simplified model representing composite beams and plates resting on the elastic bedding. More accurate models, such as sets of finite elements, are recommend for use in conjunction with simplified ones.

  17. Review of magnetocaloric effect in perovskite-type oxides

    Institute of Scientific and Technical Information of China (English)

    Zhong Wei; Au Chak-Tong; Du You-Wei


    We survey the magnetocaloric effect in perovskite-type oxides (including doped ABO3-type manganese oxides,A3B2O7-type two-layered perovskite oxides,and A2B'B''O6-type ordered double-perovskite oxides).Magnetic entropy changes larger than those of gadolinium can be observed in polycrystalline La(Ⅰ)-xCaxMnO3 and alkali-metal (Na or K)doped La0.8Ca0.2MnO3 perovskite-type manganese oxides.The large magnetic entropy change produced by an abrupt reduction of magnetization is attributed to the anomalous thermal expansion at the Curie temperature.Considerable magnetic entropy changes can also be observed in two-layered perovskites La1.6Ca1.4Mn2O7 and La2.5-xK0.5+xMn2O7+δ(0 < x < 0.5),and double-perovskite Ba2Fe1+xMo1-xO6(0 ≤ x ≤ 0.3) near their respective Curie temperatures.Compared with rare earth metals and their alloys,the perovskite-type oxides are lower in cost,and they exhibit higher chemical stability and higher electrical resistivity,which together favor lower eddy-current heating.They are potential magnetic refrigerants at high temperatures,especially near room temperature.

  18. Transp ortation of Gaussian light beam in two-layer clouds by Monte Carlo simulation%高斯光束在双层云中传输的蒙特卡罗模拟

    Institute of Scientific and Technical Information of China (English)

    孙贤明; 肖赛; 王海华; 万隆; 申晋


    基于辐射传输理论,利用蒙特卡罗方法模拟了无限窄(冲击函数)准直光束入射到典型水云以及冰水双层云时的后向散射特性,进而将得到的冲击响应与高斯光束卷积,得到高斯光束在云层中传输的多次散射特性.文中给出了两种波束入射时水云以及冰水双层云的反射函数随径向r和天顶角α的变化关系, 并给出了光强在云层内部的二维分布图. 计算结果表明, 高斯光束入射时, 云层反射函数的特点与无限窄准直光束入射时有较大区别. 因此在利用激光雷达进行云层探测时需要考虑激光的散斑,文中的方法可以为此提供理论依据.%Based on the radiative transfer theory, the backscattering characteristics of water clouds and ice-water two layers clouds irradiated by infinite narrow collimated light beam are studied by using the Monte Carlo method. The incident wavelength is 0.532 μm, and the cloud particle shape is assumed to be of sphere or plate. The single scattering char-acteristics of the clouds are computed based on the Mie theory, and the scattering angle sampling is based on the Mie phase function. The photon step adjustment is considered when the step is large enough to cross the cloud layer. The variations of reflection functions of the water clouds and ice-water two layers clouds with the radial length r and zenith angle are given, and the interior light intensity distribution of clouds are given in two dimensions. From the computed results, we find that the reflection characteristics of the two layer clouds are greatly different from those of the pure water clouds. The reflection intensity of ice clouds covered with water clouds is bigger than that of ice clouds covered with water clouds. This reason is that the sizes of ice clouds are larger than those of the water clouds, so more photons will be scattered into the interior of the clouds. The cloud layer is assumed to be linear and invariant, so the

  19. 两层土壤中正方形接地网接地电阻的解析计算%The Analytic Calculation for the Grounding Resistance of a Square Grounding Grid within a Two-layer soil

    Institute of Scientific and Technical Information of China (English)



    M.M.A.salama和Y.L.chow等人基于多重镜像原理及组合渐近线法所导出的两层土壤接地网电阻公式在一些情况下的计算误差较大,可达20%以上。为此,该文提出了改进的公式,与计算机数值方法比较,其计算误差通常都小于10%。%The deviation, under certain conditions, in calculation for grounding resistance of a grounding grid within a two-layer soil by the formula which was derived eceording to the multiple-image principle and compositive asymptetic-line solution by authors including M. M. A. Salama and Y. L. Chow, maybe up to more than 20 %. Therefore, this paper recommends a revised formula, the obtained result therefrom, in comparison with the calculated value by computer, will deviate generally less than 10%.

  20. Fibroblast growth factor 21 and its novel association with oxidative stress

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Gómez-Sámano


    Full Text Available Fibroblast growth factor 21 (FGF21 is an endocrine-member of the FGF family. It is synthesized mainly in the liver, but it is also expressed in adipose tissue, skeletal muscle, and many other organs. It has a key role in glucose and lipid metabolism, as well as in energy balance. FGF21 concentration in plasma is increased in patients with obesity, insulin resistance, and metabolic syndrome. Recent findings suggest that such increment protects tissue from an increased oxidative stress environment. Different types of physical stress, such as strenuous exercising, lactation, diabetic nephropathy, cardiovascular disease, and critical illnesses, also increase FGF21 circulating concentration. FGF21 is now considered a stress-responsive hormone in humans. The discovery of an essential response element in the FGF21 gene, for the activating transcription factor 4 (ATF4, involved in the regulation of oxidative stress, and its relation with genes such as NRF2, TBP-2, UCP3, SOD2, ERK, and p38, places FGF21 as a key regulator of the oxidative stress cell response. Its role in chronic diseases and its involvement in the treatment and follow-up of these diseases has been recently the target of new studies. The diminished oxidative stress through FGF21 pathways observed with anti-diabetic therapy is another clue of the new insights of this hormone.

  1. RNA oxidation

    DEFF Research Database (Denmark)

    Kjaer, L. K.; Cejvanovic, V.; Henriken, T.


    in diabetes resulting from the diabetic state, a dysfunction that includes increased production of hydrogen peroxide. We suggest that the intracellular RNA oxidation is compartmentalized from the traditional biomarkers in the extracellular compartment, and therefore provides independent prognostic value...... diabetes. In agreement with our previous finding, DNA oxidation did not show any prognostic value. RNA oxidation represents oxidative stress intracellularly, presumably predominantly in the cytosol. The mechanism of RNA oxidation is not clear, but hypothesized to result from mitochondrial dysfunction...

  2. 超临界CO2从含铀氧化物粉末中直接萃取铀方法研究%Study on Direct Extraction of Uranium from Uranium Oxides Powder Using Supercritical CO2

    Institute of Scientific and Technical Information of China (English)

    李佳; 朱常桂; 刘小龙; 任萌; 刘锦洪


    采用超临界CO2/硝酸-磷酸三丁酯(SC-CO2/HNO3-TBP)为萃取体系,研究各影响因素对其直接从含铀氧化物粉末中萃取铀的影响规律.结果表明:HNO3/TBP比值增大,铀萃取效率(EU)明显增大,比值为1.4时有利于萃取;比值一定时,随有机相总体积增加EU呈线性增加;萃取反应大致分为3个阶段:体系趋于稳定时的较慢阶段,稳定状态下的快速萃取阶段以及受粉末状态影响的缓慢阶段;随温度升高,EU在60℃时达到最大值91.4%;随萃取体系压力增大,EU在12 MPa时达到萃取峰值94.7%;萃取产物分离采用二级减压分离方式,在1#分离器8 MPa、2#分离器5 MPa条件下,能对萃取产物实现很好地分离.%The factors with effects on direct extraction of uranium from uranium oxides powder is studied using supercritical CO2/TBP-HNO3 extraction system.The results show that the extraction efficiency of uranium (EU) is increasing obviously with an increased HNO3/TBP,and EU is the best at the ratio value of 1.4;Under certain HNO3/TBP,EU is direct proportional to the volume of organic phase.The extraction reaction can be divided into three phases:react slowly in initial phase,fast in stable phase and slowly in final phase due to powder condition; As temperature increasing,EU has maximum value 91.4% at 60℃; As pressure increasing,EU has maximum value 94.7% at 12 MPa; According to extraction equipment condition,the best separation of extraction products can be achieved in 8 MPa (separation vessel 1) and 5 MPa (separation vessel 2).

  3. 二层SA/GA算法解决时间依赖中国邮路问题%Time-dependent Chinese Postman Problem Solved by TWO Layers SA/GA Algorithm

    Institute of Scientific and Technical Information of China (English)

    孙景昊; 吴雄; 谭国真; 闫超


    The Chinese postman problem is one of the classical problems in graph theory and has been widely and deeply researched since it was proposed. It is applicable in a wide range of fields. With the rapid development of computer networks,computer communication and intelligent transportation system, problems in time-dependent networks become more realistic than the classical problems. First, we presented the definition of time-dependent Chinese postman problem (TDCPP) and the property of TDCPP. Then we showed that the classical algorithms of Chinese postman problem (CPP) can't work in the time-dependent circumstances. Finally, two layers SA/GA algorithm(simulated annealing/genetic algorithm) was proposed, this approach was tested on some randomly generated data, the computational results were analyzed by comparing with lower bound of the problem.%中国邮路问题是图论中的经典问题,得到了深入研究和广泛应用.近年来,由于计算机网络与通信、智能交通系统等复杂应用领域的需求,研究时间依赖网络中的问题具有更为重要的现实应用意义.首先给出了时间依赖中国邮路问题的定义,然后证明了传统中国邮路问题的定理在时间依赖中国邮路问题中不成立,最后设计了二层SA/GA算法(模拟退火/遗传算法)来解决该问题,对随机产生的实例进行了测试,并根据问题下界对算法结果进行了分析.

  4. 双层堆垛长波长InAs/GaAs量子点发光性质研究%Photoluminescence Study of Two Layer Stacked InAs/GaAs Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    魏全香; 吴兵朋; 任正伟; 贺振宏; 牛智川


    研究了双层堆垛InAs/GaAs/InAs自组织量子点的生长和光致发光(PL)的物理性质.通过优化InAs淀积量、中间GaAs层厚度以及InAs量子点生长温度等生长条件,获得了室温光致发光1391~1438 nm的高质量InAs量子点.研究发现对量子点GaAs间隔层实施原位退火、采用Sb辅助生长InGaAs盖层等方法可以增强高密度(2×1010 cm-2)InAs量子点的发光强度,减小光谱线宽,改善均匀性和红移发光波长.%The molecular beam epitaxy growth and physical property of photoluminescence (PL) of two layer stacked InAs/GaAs quantum dots have been investigated. The emission wavelengths of the InAs quantum dots (QD) are extended to 1391 ~1438 nm through optimizations of growth conditions including InAs deposition amounts, thicknesses of GaAs space layers and growth temperatures. It is found that the PL intensities, wavelengths, line widths and uniformities of the high density (2X 1010 cm-2) InAs QD are improved by using in-situ annealing of GaAs interval layers and Sb assisted growth of InGaAs cover layers.

  5. Magnesium Oxide (United States)

    Magnesium is an element your body needs to function normally. Magnesium oxide may be used for different reasons. Some ... to relieve heartburn, sour stomach, or acid indigestion. Magnesium oxide also may be used as a laxative ...

  6. 二元地基基坑抽水试验及数值分析%Pumping Test and Numerical Analysis for Foundation Pit of Two-layer Foundation

    Institute of Scientific and Technical Information of China (English)

    段衍伟; 李守德; 王保田


    The foundation soil form in Qinhuai River’s lock area is the typical two-layer structure .As the pilot well loca-tion selection ,existed seepage channels ,as well as radius value selection and other factors make the calculated value of permeability coefficient in geological exploration stage having larger gap compared with the empirical value in past engi-neering practices ,for a more accurate description of the hydrogeologic conditions in site so as to provide accurate hydroge-ological parameters for precipitation design and construction ,the pumping test data is used to establish the space axisym-metric model for the foundation soil in site ,and by using the established foundation soil’s observation well model and the water level from remote bore-pressure meter for the expansion analysis of the model ,the reverse calculation is made for the soil’s permeability coefficient ,so to a certain extent ,some errors from the influencing radius and empirical fomula as well as the effect of the piping channel within the scope of on-site excavation are reduced .The subsoil’s permeability co-efficient obtained by comparing is less than that obtained in the geological exploration stage ,and closer to the empirical value from engineering practices ,thus the pit’s water out flow is made for a more accurate quantification ,which could provide a certain guiding significance for engineering practices .%秦淮河船闸地基土呈典型的二元结构地基形式,由于地质勘察阶段试验井位置选取、已有渗流通道以及影响半径取值等影响因素的存在使得地质勘查阶段渗透系数的计算值与以往的工程实践经验数值差距较大,为了更加准确的描述现场的水文地质条件,为工程降水设计、施工提供准确的水文地质参数,利用抽水试验得到的数据,对现场的地基土建立空间轴对称模型,根据建立的地基土层观测井模型以及远端孔压计所测得的水位对模型

  7. [Nitric oxide]. (United States)

    Rovira, I


    Nitric oxide was identified as the relaxing factor derived from the endothelium in 1987. Nitric oxide synthesis allows the vascular system to maintain a state of vasodilation, thereby regulating arterial pressure. Nitric oxide is also found in platelets, where it inhibits adhesion and aggregation; in the immune system, where it is responsible for the cytotoxic action of macrophages; and in the nervous system, where it acts as neurotransmitter. A deficit in endogenous synthesis of nitric oxide contributes to such conditions as essential arterial hypertension, pulmonary hypertension and heart disease. An excess of nitrous oxide induced by endotoxins and cytokinins, meanwhile, is believed to be responsible for hypotension in septic shock and for hyperdynamic circulatory state in cirrhosis of the liver. Nitric oxide has also been implicated in the rejection of transplanted organs and in cell damage after reperfusion. Inhaled nitrous oxide gas reduces pulmonary hypertension without triggering systemic hypotension in both experimental and clinical conditions. It also produces selective vasodilation when used to ventilate specific pulmonary areas, thereby improving the ventilation/perfusion ratio and, hence, oxygenation. Nitric oxide inhalation is effective in pulmonary hypertension-coincident with chronic obstructive lung disease, in persistent neonatal pulmonary hypertension and in pulmonary hypertension with congenital or acquired heart disease. Likewise, it reduces intrapulmonary shunt in acute respiratory failure and improves gas exchange. Under experimental conditions nitric oxide acts as a bronchodilator, although it seems to be less effective for this purpose in clinical use.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Oxidation behavior of Incoloy 800 under simulated supercritical water conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fulger, M. [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania)], E-mail:; Ohai, D.; Mihalache, M.; Pantiru, M. [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Malinovschi, V. [University of Pitesti, Research Center for Advanced Materials, Targul din Vale Street, No. 1, 110040 Pitesti (Romania)


    For a correct design of supercritical water-cooled reactor (SCWR) components, data regarding the behavior of candidate materials in supercritical water are necessary. Corrosion has been identified as a critical problem because the high temperature and the oxidative nature of supercritical water may accelerate the corrosion kinetics. The goal of this paper is to investigate the oxidation behavior of Incoloy 800 exposed in autoclaves under supercritical water conditions for up to 1440 h. The exposure conditions (thermal deaerated water, temperatures of 723, 773, 823 and 873 K and a pressure of 25 MPa) have been selected as relevant for a supercritical power plant concept. To investigate the structural changes of the oxide films, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and electrochemical impedance spectroscopy (EIS) analyses were used. Results show changes in the oxides chemical composition, microstructure and thickness versus testing conditions (pressure, temperature and time). The oxide films are composed of two layers: an outer layer enriched in Fe oxide and an inner layer enriched in Cr and Ni oxides corresponding to small cavities supposedly due to internal oxidation.

  9. Tunable magnetic interaction at the atomic scale in oxide heterostructures. (United States)

    Seo, J W; Prellier, W; Padhan, P; Boullay, P; Kim, J-Y; Lee, Hangil; Batista, C D; Martin, I; Chia, Elbert E M; Wu, T; Cho, B-G; Panagopoulos, C


    We report on a systematic study of a number of structurally identical but chemically distinct transition metal oxides in order to determine how the material-specific properties such as the composition and the strain affect the properties at the interface of heterostructures. Our study considers a series of structures containing two layers of ferromagnetic SrRuO₃, with antiferromagnetic insulating manganites sandwiched in between. The results demonstrate how to control the strength and relative orientation of interfacial ferromagnetism in correlated electron materials by means of valence state variation and substrate-induced strain, respectively.

  10. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H


    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  11. Effects of alloy heat treatment on oxidation kinetics and scale morphology for Crofer 22 APU (United States)

    Magdefrau, Neal J.; Chen, Lei; Sun, Ellen Y.; Aindow, Mark


    The effect of alloy heat treatment on the oxidation kinetics and oxide scale microstructure of Crofer 22 APU has been studied. Parabolic oxidation rate constants were measured for the as-received alloy and after pre-oxidation heat treatment in argon at 1050 °C for 1 and 4 h. The oxide scale microstructure was investigated using scanning electron microscopy, focused ion beam milling and transmission electron microscopy. It was found that the alloy forms a two-layer scale with a continuous chromia layer and a discontinuous MnCr2O4 overlayer. Two forms of internal oxides were also formed: subscale pockets of spinel and isolated TiOx precipitates in the underlying alloy. The pre-oxidation heat treatment had a profound effect on the grain size and morphology of the Cr2O3 and MnCr2O4 layers in the scale. The heat-treated samples exhibit a 3.5× lower parabolic oxidation rate constant than the as-received Crofer 22 APU. This improvement in oxidation resistance is attributed to the dramatic differences in the morphology of the oxide scale that forms during the earliest stages of oxidation (<5 h). The implications of these findings for oxidation mechanisms and long-term SOFC performance are discussed.

  12. Improve oxidation resistance at high temperature by nanocrystalline surface layer. (United States)

    Xia, Z X; Zhang, C; Huang, X F; Liu, W B; Yang, Z G


    An interesting change of scale sequence occurred during oxidation of nanocrystalline surface layer by means of a surface mechanical attrition treatment. The three-layer oxide structure from the surface towards the matrix is Fe3O4, spinel FeCr2O4 and corundum (Fe,Cr)2O3, which is different from the typical two-layer scale consisted of an Fe3O4 outer layer and an FeCr2O4 inner layer in conventional P91 steel. The diffusivity of Cr, Fe and O is enhanced concurrently in the nanocrystalline surface layer, which causes the fast oxidation in the initial oxidation stage. The formation of (Fe,Cr)2O3 inner layer would inhabit fast diffusion of alloy elements in the nanocrystalline surface layer of P91 steel in the later oxidation stage, and it causes a decrease in the parabolic oxidation rate compared with conventional specimens. This study provides a novel approach to improve the oxidation resistance of heat resistant steel without changing its Cr content.

  13. Iron Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla; Amonette, James E.


    Abstract: Fe oxides are common clay-sized oxide, oxyhydroxide and hydroxide soil minerals. They are compounds of Fe, O, and H that have structures based on close-packed arrays of O. The octahedral and tetrahedral cavities within these arrays are filled with either Fe3+ or Fe2+ to form Fe(O/OH)6, FeO6, or FeO4 structural units. All of the naturally occurring Fe oxide minerals usually undergo some degree of isomorphous substitution of other metal ions for Fe in their structures. Relatively simple techniques may be used to identify Fe oxides in the field based on their typical colors and magnetic properties. In the laboratory, a variety of instrumental techniques can be used to confirm phase identity and to quantify amount. Of these, X-ray diffraction, infrared spectroscopy, electron microscopy, thermal analysis, and Mössbauer spectroscopy are the most commonly used techniques. As oxides, the functional groups on their surfaces may have positive, negative, or no charge depending on pH and on the concentration and nature of other ions in the contact solution. A net positive surface charge usually is observed in soils because Fe oxides have a point-of-zero-charge in the neutral or slightly basic pHs. The functional groups on the surface form complexes with cations and anions from the aqueous phase. Their sorption and electron-buffering properties significantly affect the geochemical cycles of almost all elements having agronomic or environmental significance.

  14. Natural convection of the oxide pool in a three-layer configuration of core melts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Su-Hyeon; Park, Hae-Kyun; Chung, Bum-Jin, E-mail:


    Highlights: • Natural convection of oxide pool in 3-layer configuration during IVR was investigated. • High Ra was achieved by using mass transfer experiments based on analogy concept. • Heat ratio to light metal layer was 14% higher for 3-layer configuration than 2-layer one. • Heat transfer to heavy metal layer was poor and hence heat load to side wall increased. • Angular heat loads to side wall showed strengthened heat focusing at uppermost location. - Abstract: We investigated the natural convection of the oxide layer in a three-layer configuration of core melts in a severe accident. In order to achieve high modified Rayleigh numbers of 10{sup 12}–10{sup 13}, mass transfer experiments were performed using a copper sulfate electroplating system based upon the analogy between heat and mass transfer. Four different cooling conditions of the top and the bottom plates were tested. The upward heat ratios were 14% higher for three-layer than for two-layer due to the reduced heights and the downward heat ratios were lower the same amount. The local Nusselt numbers for the top and the bottom plates were measured and compared with the two layer configuration. To explore the heat load to the reactor vessel, the angle-dependent heat fluxes at the side wall, were measured and compared with the two-layer configuration. Heat load to the side wall and peak heat at the uppermost location were intensified for the three-layer configuration.

  15. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Osredkar Joško


    Full Text Available The human organism is exposed to the influence of various forms of stress, either physical, psychological or chemical, which all have in common that they may adversely affect our body. A certain amount of stress is always present and somehow directs, promotes or inhibits the functioning of the human body. Unfortunately, we are now too many and too often exposed to excessive stress, which certainly has adverse consequences. This is especially true for a particular type of stress, called oxidative stress. All aerobic organisms are exposed to this type of stress because they produce energy by using oxygen. For this type of stress you could say that it is rather imperceptibly involved in our lives, as it becomes apparent only at the outbreak of certain diseases. Today we are well aware of the adverse impact of radicals, whose surplus is the main cause of oxidative stress. However, the key problem remains the detection of oxidative stress, which would allow us to undertake timely action and prevent outbreak of many diseases of our time. There are many factors that promote oxidative stress, among them are certainly a fast lifestyle and environmental pollution. The increase in oxidative stress can also trigger intense physical activity that is directly associated with an increased oxygen consumption and the resulting formation of free radicals. Considering generally positive attitude to physical activity, this fact may seem at first glance contradictory, but the finding has been confimed by several studies in active athletes. Training of a top athlete daily demands great physical effort, which is also reflected in the oxidative state of the organism. However, it should be noted that the top athletes in comparison with normal individuals have a different defense system, which can counteract the negative effects of oxidative stress. Quite the opposite is true for irregular or excessive physical activity to which the body is not adapted.

  16. Oxidation catalyst (United States)

    Ceyer, Sylvia T.; Lahr, David L.


    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  17. Photoelectrochemical water splitting for hydrogen production with metal oxide (hematite and cupric oxide) based photocatalysts (United States)

    Tang, Houwen

    generated photocurrent, we developed a two-layer structure in which a thin layer of Cu-Ti-O was deposited on bare CuO thin film as a protective layer. Our experimental results indicated that this two-layer structure has an ideal thickness for the protection layer and is suitable for high-performance and long-term application for PEC water splitting.

  18. Thin coatings for protecting titanium aluminides in high-temperature oxidizing environments (United States)

    Wiedemann, K. E.; Taylor, P. J.; Clark, R. K.; Wallace, T. A.


    Titanium aluminides have high specific strengths at high temperatures but are susceptible to environmental attack. Their use in many aerospace applications would require that they be protected with coatings that, for structural efficiency, must be thin. It is conceivable that acceptable coatings might be found in several oxide systems, and consequently, oxide coatings of many compositions were prepared from sol-gels for study. Response-surface methodology was used to refine coating compositions and factorial experiments were used to develop coating strategies. Oxygen permeability diagrams of two-layer coatings for several oxide systems, an analysis of multiple-layer coatings on rough and polished surfaces, and modeling of the oxidation weight gain are presented.

  19. MOS structure fabrication by thermal oxidation of multilayer metal thin films

    Institute of Scientific and Technical Information of China (English)

    Mohammad Orvatiniat; Atefeh Chahkoutahi


    A novel approach for the fabrication of a metal oxide semiconductor (MOS) structure was reported.The process comprises electrochemical deposition of aluminum and zinc layers on a base of nickel-chromium alloy.This two-layer structure was thermally oxidized at 400 ℃ for 40 min to produce thin layers of aluminum oxide as an insulator and zinc oxide as a semiconductor on a metallic substrate.Using deposition parameters,device dimensions and SEM micrographs of the layers,the device parameters were calculated.The resultant MOS structure was characterized by a C-V curve method.From this curve,the device maximum capacitance and threshold voltage were estimated to be about 0.74 nF and -2.9 V,respectively,which are in the order of model-based calculations.

  20. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka


    Full Text Available The unceasing need for oxygen is in contradiction to the fact that it is in fact toxic to mammals. Namely, its monovalent reduction can have as a consequence the production of short-living, chemically very active free radicals and certain non-radical agents (nitrogen-oxide, superoxide-anion-radicals, hydroxyl radicals, peroxyl radicals, singlet oxygen, peroxynitrite, hydrogen peroxide, hypochlorous acid, and others. There is no doubt that they have numerous positive roles, but when their production is stepped up to such an extent that the organism cannot eliminate them with its antioxidants (superoxide-dismutase, glutathione-peroxidase, catalase, transferrin, ceruloplasmin, reduced glutathion, and others, a series of disorders is developed that are jointly called „oxidative stress.“ The reactive oxygen species which characterize oxidative stress are capable of attacking all main classes of biological macromolecules, actually proteins, DNA and RNA molecules, and in particular lipids. The free radicals influence lipid peroxidation in cellular membranes, oxidative damage to DNA and RNA molecules, the development of genetic mutations, fragmentation, and the altered function of various protein molecules. All of this results in the following consequences: disrupted permeability of cellular membranes, disrupted cellular signalization and ion homeostasis, reduced or loss of function of damaged proteins, and similar. That is why the free radicals that are released during oxidative stress are considered pathogenic agents of numerous diseases and ageing. The type of damage that will occur, and when it will take place, depends on the nature of the free radicals, their site of action and their source. [Projekat Ministarstva nauke Republike Srbije, br. 173034, br. 175061 i br. 31085

  1. Defects and ferromagnetism in transition metal doped zinc oxide (United States)

    Thapa, Sunil

    Transition metal doped zinc oxide has been studied recently due to its potential application in spintronic devices. The magnetic semiconductor, often called Diluted Magnetic Semiconductors (DMS), has the ability to incorporate both charge and spin into a single formalism. Despite a large number of studies on ferromagnetism in ZnO based DMS and the realization of its room temperature ferromagnetism, there is still a debate about the origin of the ferromagnetism. In this work, the synthesis and characterization of transition metal doped zinc oxide have been carried out. The sol-gel method was used to synthesize thin films, and they were subsequently annealed in air. Characterization of doped zinc oxide films was carried out using the UV-visible range spectrometer, scanning electron microscopy, superconducting quantum interference device (SQUID), x-ray diffraction(XRD) and positron annihilation spectroscopy. Hysteresis loops were obtained for copper and manganese doped zinc oxide, but a reversed hysteresis loop was observed for 2% Al 3% Co doped zinc oxide. The reversed hysteresis loop has been explained using a two-layer model.

  2. Effect of intense pulsed ion beams irradiation on the oxidation behavior of gamma sup ' -based superalloy

    CERN Document Server

    Zhang Hong Tao; Han Bao Xi; Yan Sha; Zhao Wei Jiang; Han Ya Fan


    Intense pulsed ion beams (IPIB) with three different power densities (25, 37.5 and 50 MW/cm sup 2) are employed for the surface treatment of gamma sup ' -based superalloy IC6. The influence of IPIB irradiation on the oxidation behavior of IC6 at 1100 degree sign C for up to 100 h is investigated. It is found that the phase states of IC6 are dramatically changed after IPIB irradiation and the oxidation behavior of the irradiated coupons depends greatly on the power density of IPIB. IPIB irradiation with a power density of 25 or 37.5 MW/cm sup 2 significantly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to a change in the oxidation products from a three-layered scale of Ni-rich oxides for the unirradiated coupon to a two-layered scale of Mo- and Al-rich oxides. In contrast, IPIB irradiation with a power density of 50 MW/cm sup 2 proves to be detrimental, causing a higher oxidation rate. The oxidation mechanism for IPIB irradiat...

  3. PREFACE: Semiconducting oxides Semiconducting oxides (United States)

    Catlow, Richard; Walsh, Aron


    Semiconducting oxides are amongst the most widely studied and topical materials in contemporary condensed matter science, with interest being driven both by the fundamental challenges posed by their electronic and magnetic structures and properties, and by the wide range of applications, including those in catalysis and electronic devices. This special section aims to highlight recent developments in the physics of these materials, and to show the link between developing fundamental understanding and key application areas of oxide semiconductors. Several aspects of the physics of this wide and expanding range of materials are explored in this special section. Transparent semiconducting oxides have a growing role in several technologies, but challenges remain in understanding their electronic structure and the physics of charge carriers. A related problem concerns the nature of redox processes and the reactions which interconvert defects and charge carriers—a key issue which may limit the extent to which doping strategies may be used to alter electronic properties. The magnetic structures of the materials pose several challenges, while surface structures and properties are vital in controlling catalytic properties, including photochemical processes. The field profits from and exploits a wide range of contemporary physical techniques—both experimental and theoretical. Indeed, the interplay between experiment and computation is a key aspect of contemporary work. A number of articles describe applications of computational methods whose use, especially in modelling properties of defects in these materials, has a long and successful history. Several papers in this special section relate to work presented at a symposium within the European Materials Research Society (EMRS) meeting held in Warsaw in September 2010, and we are grateful to the EMRS for supporting this symposium. We would also like to thank the editorial staff of Journal of Physics: Condensed Matter for

  4. Two-Layer Models for Landslide-Generated Tsunamis (United States)

    Kirby, J. T., Jr.; Nicolsky, D.; Ma, G.; Shi, F.; Hsu, T. J.; Schnyder, J. S. D.


    We describe the development of a model for landslide tsunami generation based on a depth-integrated, fully deformable lower layer, and apply the resulting model to several laboratory and field cases. The approach follows on earlier studies where models for the slide layer and overlying water layer are formulated in the depth integrated, shallow water approximation, with kinematic and pressure coupling between the layers. In the present study, we use the 3D nonhydrostatic model of Ma et al (2012) to retain fully dispersive behavior in the upper fluid layer. In perfect fluid applications for shallow or intermediate depth waves, the model has been shown to predict tsunami response to solid slides (Enet and Grilli, 2007) with good accuracy using only three vertical sigma levels, making it computationally competitive with weakly dispersive Boussinesq formulations using a single depth-integrated layer. The effect of non-hydrostatic acceleration effects in the lower, depth integrated layer (resulting from steep substrate slopes) is implemented using the approach of Yamazaki et al (2009), who used a layer-averaged approximation for vertical acceleration to correct the hydrostatic pressure distribution. The two coupled models are formulated using a finite volume, TVD approach. Lateral boundaries of the slide volume may be arbitrarily approached relative to the initial still water shoreline, and thus the triggering event may be either submarine, subaerial, or a combination of the two. In our first implementation, we assume the lower layer to be a simple, viscous Newtonian fluid, following the approach of Jiang and LeBlond (1994) as corrected by Fine et al (1998). An alternate model is also constructed based on a rheology model representing a granular or debris flow supported by intergranular stresses, following Savage and Hutter (1989) and Iverson (1997). Both models amount to the addition of a single mass and horizontal momentum equation to the three-layer perfect fluid model, and hence the added complexity over the solid slide case of Ma et al (2012) is minimal. Each model is then applied to a range of cases, including laboratory measurements of a rapid subaerial slide (Mohammed and Fritz, 2012), and a potential collapse of the the southern Great Bahama Bank platform margin (Schnyder et al, 2013).

  5. Two layers of Australian impact ejecta in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.; Gupta, S.M.; Kodagali, V.N.

    Only 2 Australian tektites have been found in the Indian Ocean, and both are associated with surficial sediments. Cores from both locations are collected, where the tektites have been reported. The microtektites in these cores (and both the tekties...

  6. Merging polygons on two-layer printed circuit board

    Directory of Open Access Journals (Sweden)

    Murov S. Yu.


    Full Text Available A method is proposed for solving the problem of connection of maximum number of isolated islands of metallized areas of the same chain, located on different layers of the printed circuit board. The method can be used in the automatic tracing of the boards.

  7. Palladium Electrodeposition onto Pt(100): Two-Layer Underpotential Deposition. (United States)

    Previdello, Bruno A F; Sibert, Eric; Maret, Mireille; Soldo-Olivier, Yvonne


    Electrodeposition of the first Pd layers onto Pt(100) was investigated using cyclic voltammetry at a low scan rate (0.1 mV·s(-1)). Ultrathin films were characterized by cyclic voltammetry in 0.1 M H2SO4 solution and with ex situ AFM (atomic force microscopy). For the first time, we evidenced the underpotential character of the deposition of the first two Pd layers, characterized by a two-step mechanism, each step corresponding to the deposition of a complete Pd atomic layer. For thicker deposits, especially above 10 monolayers as equivalent thickness, the electrochemical characterization displays a strong irreversibility and a broadening of the adsorption/desorption peaks, associated with a reduction of long-range ordered flat areas. Ex situ AFM images are in agreement with this description. They show rough thick deposits and the growth of (100)-oriented rectangular shaped islands with their sides aligned with the two [011] and [0-11] perpendicular directions of the (100) Pt surface.

  8. Ultraefficient reduced model for countercurrent two-layer flows (United States)

    Lavalle, Gianluca; Vila, Jean-Paul; Lucquiaud, Mathieu; Valluri, Prashant


    We investigate the dynamics of two superposed layers with density contrast flowing countercurrent inside a channel, when the lower layer is much thinner than the wavelength of interfacial waves. We apply a low-dimensional film model to the bottom (heavier) layer and introduce a fast and efficient method to predict the onset of flow reversal in this phase. We study three vertical scenarios with different applied pressure gradients and compare the temporal growth rates of linear and weakly nonlinear waves to the Orr-Sommerfeld problem and to the weakly nonlinear theory, respectively. At the loading point, i.e., when a large wave hump stands at the interface, our spatiotemporal analysis shows that the system is absolutely unstable. We then present profiles of nonlinear saturated waves, pressure field, and streamline distribution in agreement with direct numerical simulation. The reduced model presented here allows us to explore the effect of the upper-layer speed on the wave pattern, showing that the wave profile is very sensitive when the mean film thickness, rather than the liquid flow rate, is maintained constant in the simulation. In addition, we show the strong effect of surface tension on both the maximum wave hump and the crest steepness before the loading point. Finally, we reveal how the nonlinear wave speed affects the vortex distribution within the lower layer by analyzing the stream function under different scenarios.

  9. Influences of Yttrium on Cyclic Oxidation Behavior of Fe-Cr-Al Alloy

    Institute of Scientific and Technical Information of China (English)

    辛丽; 李美栓; 钱余海; 李铁藩


    The 1100 ℃ cyclic oxidation behavior of Fe-23Cr-5Al alloy modified by yttrium was studied. Yttrium was added to this alloy in the form of (1) metallic addition, (2) yttrium oxide dispersion and (3) ion implantation. Cracking and spalling occurred on the convoluted scale formed on Y-free alloy and the substrate was exposed. A flat dense scale without spallation was formed on the yttrium alloying addition or yttrium oxide dispersion alloy. Spallation mainly occurred between two layers of the scale on the 1×1017Y ions/cm2-implanted alloy. The results indicate the main reason that the adhesion of alumina scale was improved by yttrium addition lies in that yttrium is liable to form a stable yttrium sulfide with sulfur in the alloy and prevent sulfur interface segregation. Another reason is that the growth mechanism of alumina scale was changed by yttrium addition.

  10. Work function shifts of a zinc oxide surface upon deposition of self-assembled monolayers: a theoretical insight. (United States)

    Cornil, D; Van Regemorter, T; Beljonne, D; Cornil, J


    We have investigated at the theoretical Density Functional Theory level the way the work function of zinc oxide layers is affected upon deposition of self-assembled monolayers (SAMs). 4-tert-Butylpyridine (4TBP) and various benzoic acids (BA) were adsorbed on the apolar (101[combining macron]0) ZnO and used as probe systems to assess the influence of several molecular parameters. For the benzoid acids, we have investigated the impact of changing the nature of the terminal group (H, CN, OCH3) and the binding mode of the carboxylic acid (monodentate versus bidentate) on the apolar (101[combining macron]0) surface. For each system, we have quantified the contribution from the molecular core and the anchoring group as well as of the degree of surface reconstruction on the work function shift. For the benzoic acids, the structural reorganization of the surface induces a negative shift of the work function by about 0.3 ± 0.15 eV depending on the nature of the binding mode, irrespective of the nature of the terminal function. The bond-dipole potential strongly contributes to the modification of the work function, with values in the range +1.2 to +2.0 eV. In the case of 4TBP, we further characterized the influence of the degree of coverage and of co-adsorbed species (H, OH, and water molecules) on the ZnO/SAM electronic properties as well as the influence of the ZnO surface polarity by considering several models of the polar (0001) ZnO surface. The introduction of water molecules in the (un)dissociated form at full coverage on the non-polar surface only reduces the work function by 0.3-0.4 eV compared to a reference system without co-adsorbed species. Regarding the polar surface, the work function is also significantly reduced upon deposition of a single 4BTP molecule (from -1.44 eV to -1.73 eV for our model structures), with a shift similar in direction and magnitude compared to the non-polar surfaces.

  11. 双层CuO2铜酸盐高温超导体的临界温度与电负性标度%Electronegativity and Tc in High-Temperature Superconduct ors of Cuprate HTSC with Two Layers of CuO2

    Institute of Scientific and Technical Information of China (English)



    The diffence between the geometri averages of ne gative of energy of valence orbit for cations and anions in suggested conducting -resonance-elements of some cuprate high-temperature superconductors with two layers of CuO2 are evaluated.The relationship between ΔX0 and crisis t hemperature Tc was found to fit line.%一些有代表性的双层CuO2铜酸盐高温超导体中假 设的导电共振单元的阴离子和阳离子的价层轨道能负值的几何平均值的差(ΔX0 )与临界温度Tc存在线性关系.

  12. 液层厚度比对环形腔内双层液体的热毛细对流稳定性的影响%Influence of liquid layer depth ratio on stability of thermocapillary flow in annular two-layer system with upper rigid wall

    Institute of Scientific and Technical Information of China (English)



    In order to understand the liquid layer depth ratio on the stability of two-layer system with upper rigid walls at the microgravity condition,a linear stability analysis of thermocapillary flow in the annular immiscible two-layer system of 5cSt silicone oil and HT-70 was carried out using Implicity Restarted Arnoldi Method (IRAM).Critical values of Marangoni number,wave number and phase velocity were obtained at different liquid layer depth ratios,different aspect ratios of the cavity and different radius rations.The thermofluid wave pattern at the liquid-liquid interface near the critical Marangoni number was also exhibited.%为了了解微重力条件下、水平温度梯度作用时,上部为固壁的环形腔内双层流体系统中液层厚度比对流动稳定性的影响,采用隐式重启 Arnoldi方法(IRAM)对环形池内5cSt 硅油/HT-70双层流体的热对流过程进行了线性稳定性分析,获得了不同液层厚度比下系统流动的临界 Marangoni 数、临界波数、临界相速度,并通过计算特征向量,得到了临界 Marangoni数附近液-液界面的热流体波形态。

  13. Thermally exfoliated graphite oxide (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)


    A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

  14. Photo-oxidation catalysts (United States)

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis


    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  15. 基于令牌环的两层工业无线测控网络系统的设计与实现%The Design and Implementation of Token Ring-based Two-layer Industrial Wireless Monitoring and Control Network System

    Institute of Scientific and Technical Information of China (English)

    杨之乐; 王秉臣; 费敏锐; 姚奇; 侯维岩


    为应对工业无线测控需要而提出的单跳令牌环网受无线模块通信距离限制,无法满足实际工业应用需求.为了延长通信距离,扩大令牌环网应用范围,提出一种在基于原令牌环协议的基础上挂接主从的两层无线监控网络WICN - TL( Wireless Industrial Control Network -Two Layers),介绍了其协议模型的拓扑结构及通信流程,将该协议在基于IEEE802.15.4a的硬件平台NanoNET 上加以实现,并接入PROFIBUS - DP现场总线系统,在某污水处理厂进行了实地测试.测试结果表明,该协议具有良好的通信能力和较大的覆盖范围,能够适应工业环境的应用需要.

  16. The Effect of Zirconium Addition on the Oxidation Resistance of Aluminide Coatings (United States)

    Zagula-Yavorska, Maryana; Pytel, Maciej; Romanowska, Jolanta; Sieniawski, Jan


    Nickel, Mar M247, and Mar M200 superalloys were coated with zirconium-doped aluminide deposited by the chemical vapor deposition method. All coatings consisted of two layers: an additive one, comprising of the β-NiAl phase and the interdiffusion one. The interdiffusion layer on pure nickel consisted of the γ'-Ni3Al phase and β-NiAl phase on superalloys. Precipitations of zirconium-rich particles were found near the coating's surface and at the interface between the additive and the interdiffusion layer. Zirconium doping of aluminide coating improved the oxidation resistance of aluminide coatings deposited both on the nickel substrate and on the Mar M200 superalloy. Precipitations of ZrO2 embedded by the Al2O3 oxide were formed during oxidation. It seems that the ZrO2 oxide increases adhesion of the Al2O3 oxide to the coating and decreases the propensity of the Al2O3 oxide rumpling and spalling.

  17. Oxidation and Hot Corrosion of Gradient Thermal Barrier Coatings Prepared by EB-PVD

    Institute of Scientific and Technical Information of China (English)


    The performances of gradient thermal barrier coatings (GTBCs) produced by EB-PVD were evaluated by isothermaloxidation and cyclic hot corrosion (HTHC) tests. Compared with conventional two-layered TBCs, the GTBCs exhibitebetter resistance to not only oxidation but also hot-corrosion. A dense Al2O3 layer in the GTBCs effectively prohibitesinward diffusion of O and S and outward diffusion of Al and Cr during the tests. On the other hand, an "inlaid"interface, resulting from oxidation of the Al along the columnar grains of the bond coat, enhances the adherence ofAl2O3 layer. Failure of the GTBC finally occurred by cracking at the interface between the bond coat and Al2O3layer, due to the combined effect of sulfidation of the bond coat and thermal cycling.

  18. Oxidation and thermal fatigue of EB-PVD thermal barrier coatings on tube superalloy substrate

    Institute of Scientific and Technical Information of China (English)

    GAO Yu; ZHANG Chun-xia; ZHOU Chun-gen; GONG Sheng-kai; XU Hui-bin


    Two-layer structure thermal barrier coatings (TBCs) (NiCoCrAlY (bond coat)+(6%-8%, mass fraction) Y2O3-stabilized ZrO2(YSZ top coat)) were deposited by electron beam physical vapor deposition (EB-PVD) on tube superalloy substrates. The samples were investigated by isothermal oxidation and thermal shock tests. It is found that the mass gains of the substrate with and without TBCs are 0.165 and 7.34 mg/cm2, respectively. So the TBCs system is a suitable protection for the substrate. In thermal shock tests the vertical cracks initiate at the top coat and grow into the bond coat, causing the oxidation of the bond coat along the cracks. Failure of the TBCs system occurs by the spallation of the YSZ from the bond coat, and some micro-cracks are found at the location where the fragment of the YSZ top coat spalled from.

  19. Oxidative stress and myocarditis. (United States)

    Tada, Yuko; Suzuki, Jun-Ichi


    Reactive oxygen species (ROS) such as superoxide anion and hydrogen peroxide are produced highly in myocarditis. ROS, which not only act as effectors for pathogen killing but also mediate signal transduction in the stress responsive pathways, are closely related with both innate and adaptive immunity. On the other hand, oxidative stress overwhelming the capacity of anti-oxidative system generated in severe inflammation has been suggested to damage tissues and exacerbate inflammation. Oxidative stress worsens the autoimmunological process of myocarditis, and suppression of the anti-oxidative system and long-lasting oxidative stress could be one of the pathological mechanisms of cardiac remodeling leading to inflammatory cardiomyopathy. Oxidative stress is considered to be one of the promising treatment targets of myocarditis. Evidences of anti-oxidative treatments in myocarditis have not been fully established. Basic strategies of anti-oxidative treatments include inhibition of ROS production, activation of anti-oxidative enzymes and elimination of generated free radicals. ROS are produced by mitochondrial respiratory chain reactions and enzymes including NADPH oxidases, cyclooxygenase, and xanthine oxidase. Other systems involved in inflammation and stress response, such as NF-κB, Nrf2/Keap1, and neurohumoral factors also influence oxidative stress in myocarditis. The efficacy of anti-oxidative treatments could also depend on the etiology and the phases of myocarditis. We review in this article the pathological significance of ROS and oxidative stress, and the potential anti-oxidative treatments in myocarditis.

  20. Electrolytic oxidation of anthracite (United States)

    Senftle, F.E.; Patton, K.M.; Heard, I.


    An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

  1. Zinc oxide overdose (United States)

    Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

  2. Bridged graphite oxide materials (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)


    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  3. Oxidative Stress in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Varsha Shukla


    Full Text Available It has been demonstrated that oxidative stress has a ubiquitous role in neurodegenerative diseases. Major source of oxidative stress due to reactive oxygen species (ROS is related to mitochondria as an endogenous source. Although there is ample evidence from tissues of patients with neurodegenerative disorders of morphological, biochemical, and molecular abnormalities in mitochondria, it is still not very clear whether the oxidative stress itself contributes to the onset of neurodegeneration or it is part of the neurodegenerative process as secondary manifestation. This paper begins with an overview of how oxidative stress occurs, discussing various oxidants and antioxidants, and role of oxidative stress in diseases in general. It highlights the role of oxidative stress in neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis. The last part of the paper describes the role of oxidative stress causing deregulation of cyclin-dependent kinase 5 (Cdk5 hyperactivity associated with neurodegeneration.

  4. Nitrous Oxide Flux (United States)

    U.S. Geological Survey, Department of the Interior — Nitrous Oxide (N20) flux is the net rate of nitrous oxide exchange between an ecosystem and the atmosphere. Data of this variable were generated by the USGS...

  5. Oxidative Stress in BPH

    Directory of Open Access Journals (Sweden)

    Murat Savas


    The present study has shown that there were not relationship between potency of oxidative stress and BPH. Further well designed studies should be planned to find out whether the oxidative stress-related parameters play role in BPH as an interesting pathology in regard of the etiopathogenesis. Keywords: benign prostatic hyperplasia, oxidative stress, prostate

  6. Transient Oxidation of a γ-Ni-28Cr-11Al Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, L; Hovis, D B; Heuer, A H [Case Western


    γ-NiCrAl alloys with relatively low Al contents tend to form a layered oxide scale during the early stages of oxidation, rather than an exclusive α-Al2O3 scale, the so-called 'thermally grown oxide' (TGO). A layered oxide scale was established on a model γ-Ni-28Cr-11Al (at.%) alloy after isothermal oxidation for several minutes at 1100 °C. The layered scale consisted of an NiO layer at the oxide/gas interface, an inner Cr2O3 layer, and an α-Al2O3 layer at the oxide/alloy interface. The evolution of such an NiO/Cr2O3/Al2O3 layered structure on this alloy differs from that proposed in earlier work. During heating, a Cr2O3 outer layer and a discontinuous inner layer of Al2O3 initially formed, with metallic Ni particles dispersed between the two layers. A rapid transformation occurred in the scale shortly after the sample reached maximum temperature (1100°C), when two (possibly coupled) phenomena occurred: (i) the inner transition alumina transformed to α-Al2O3, and (ii) Ni particles oxidized to form the outer NiO layer. Subsequently, NiO reacted with Cr2O3 and Al2O3 to form spinel. Continued growth of the oxide scale and development of the TGO was dominated by growth of the inner α-Al2O3 layer.

  7. Oxide catalysts for oxidation of xylene

    Directory of Open Access Journals (Sweden)

    Kusman Dossumov


    Full Text Available Polioxide granulated catalysts based on transition and rare earth metals for oxidative conversion of xylene by oxygen have been investigated. It was defined the effect of the composition and concentration of the active phase of oxide catalysts: Cu-Mn-Ln; Cu-Mn-Ce and Cu-Mn-Nd on the o-xylene oxidation. It was found that the Cu-Mn-Ce catalyst has the highest activity at the concentrations of metals: copper – 3.0%; manganese – 3.0%; cerium – 1.0%.

  8. Characterization of high-temperature oxide films on dysprosium-doped Fe-20Cr alloys by electrochemical techniques

    Institute of Scientific and Technical Information of China (English)

    GUO Pingyi; ZENG Chaoliu; SHAO Yong; QIN Zeshang


    The oxidation propegies of Fe-20Cr,Fe-20Cr-0.2Dy and Fe-20Cr-1Dy alloys were studied using gravimetric and electrochemical techniques.The high-temperature oxide films of Dy-doped Fe-20Cr alloys were prepared in air at 900 ℃ for 24,48 and 100 h,respectively.The electrochemical experiment was performed by a three-electrode electrochemical cell and in 0.1 mol/L Na2SO4 aqueous solution.Proper models were built for describing electrochemical impedance spectroscopy of the different oxide layers and the spectra were interpreted in terms of a two-layer model of the films.The results revealed that the oxide films of Dy-doped Fe-20Cr alloys became compacter than that of undoped alloys and retained their good protective ability for a relatively long time.With increasing content of Dy,the protection of the oxide films slightly decreased.Mott-Schottky curves indicated that all the oxides were n-type semi-conductors,and the Nd value of oxide film on Fe-20Cr was much larger than that of Dy-doped Fe-20Cr alloys.The results of kinetic curves and SEM were in agreement with electrochemical impedance spectroscopy and Mott-Schottky data.

  9. Microstructure of GaAs/AlAs/GaAs with and without oxidation

    CERN Document Server

    Wang Yong; Wang Wen Chong; Liu Cui Xiu; Chen Xiang Ming; Mai Zhen Hong; Zheng Wen Li; Jia Quan Jie; Jiang Xiao Ming


    The Changes of compositions and microstructures of GaAs/AlAS/GaAs trilayer before and after oxidation were investigated. GaAs/Al sub 2 O sub 3 /GaAs thin film was obtained from GaAs/AlAs/GaAs by lateral oxidation and its microstructures were investigated by use of X-ray small angle reflectivity and high angle diffraction. The results show that before oxidation there exists an even transition layer with the thickness of 110 Angstrom between the AlAs layer and the upper GaAs layer. The AlAs layer was separated into two layers, one is of 40 Angstrom thickness and the other 1050 Angstrom. The average atomic density of the thin AlAs layer is less than that of the thick AlAs layer. After lateral oxidation, AlAs was oxidized into Al sub 2 O sub 3 , and the thickness and roughness of the transition layer mentioned above decrease

  10. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.


    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  11. All-Oxide Photovoltaics. (United States)

    Rühle, Sven; Anderson, Assaf Y; Barad, Hannah-Noa; Kupfer, Benjamin; Bouhadana, Yaniv; Rosh-Hodesh, Eli; Zaban, Arie


    Recently, a new field in photovoltaics (PV) has emerged, focusing on solar cells that are entirely based on metal oxide semiconductors. The all-oxide PV approach is very attractive due to the chemical stability, nontoxicity, and abundance of many metal oxides that potentially allow manufacturing under ambient conditions. Already today, metal oxides (MOs) are widely used as components in PV cells such as transparent conducting front electrodes or electron-transport layers, while only very few MOs have been used as light absorbers. In this Perspective, we review recent developments of all-oxide PV systems, which until today were mostly based on Cu2O as an absorber. Furthermore, ferroelectric BiFeO3-based PV systems are discussed, which have recently attracted considerable attention. The performance of all-oxide PV cells is discussed in terms of general PV principles, and directions for progress are proposed, pointing toward the development of novel metal oxide semiconductors using combinatorial methods.


    Energy Technology Data Exchange (ETDEWEB)

    Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.


    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  13. Oxidation Resistant Graphite Studies

    Energy Technology Data Exchange (ETDEWEB)

    W. Windes; R. Smith


    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  14. Anticonvulsant drugs, oxidative stress and nitric oxide. (United States)

    Vega Rasgado, L A; Ceballos Reyes, G M; Vega-Diaz, M F


    Nitric Oxide (NO) is thought to play a fundamental role in the genesis and the spreading of epileptiform hyperactivity, although its function is unclear and controversial. As a free radical, NO may cause oxidative stress, which is emerging as an important mechanism in the etiology of seizure-induced neuronal death. Here we investigated the role of NO in seizure mechanisms through oxidative stress generation by studying the effect of anticonvulsant drugs such as amino oxyacetic acid (AAOA), valproate (VALP), diazepam (DIAZ) and gabapentin (GBPTNA) on oxidative stress in the brain, estimated as free carbonyls by the method of Dalle and Rossi, and by measuring NO by the indirect method based on the Griess reaction. Results show that, except for AAOA and VALP, anticonvulsants did not significantly affect or decreased free carbonyls, but reversed the oxidative stress produced by pentylenetetrazole (PTZ) induced convulsions. Anticonvulsants except AAOA diminished NO levels and with the exception of VALP, counteracted the increase in NO generated by PTZ. Anticonvulsants decreased oxidative stress and NO especially in hippocampus (HI) and cortex (CX), and reversed PTZ effects on both parameters. PTZ diminished NO in HI, which could be explained since PTZ caused an increase on endothelial NO synthase but a decrease in neuronal NOS expression in this brain area. Since the drugs studied are modulating GABA levels, our results suggest that seizures generated by alterations in GABAergic transmission produce oxidative stress caused by NO, which can be reversed by anticonvulsants. The effects described differ among the brain regions studied and the NO synthase isoform affected.

  15. Barium oxide, calcium oxide, magnesia, and alkali oxide free glass (United States)

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar


    A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

  16. Oxidizer Scoping Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chancellor, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The purpose of this report is to present the results of the acceptable knowledge (AK) review of oxidizers present in active waste streams, provide a technical analysis of the oxidizers, and report the results of the scoping study testing. This report will determine the fastest burning oxidizer to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-002, Sorbent Scoping Studies, contains similar information for sorbents identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.


    Energy Technology Data Exchange (ETDEWEB)



    This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

  18. Metal oxides as photocatalysts

    Directory of Open Access Journals (Sweden)

    Mohammad Mansoob Khan


    Full Text Available Metal oxides are of great technological importance in environmental remediation and electronics because of their capability to generate charge carriers when stimulated with required amount of energy. The promising arrangement of electronic structure, light absorption properties, and charge transport characteristics of most of the metal oxides has made possible its application as photocatalyst. In this article definition of metal oxides as photocatalyst, structural characteristics, requirements of the photocatalyst, classification of photocatalysts and the mechanism of the photocatalytic process are discussed.

  19. Molecular water oxidation catalysis

    CERN Document Server

    Llobet, Antoni


    Photocatalytic water splitting is a promising strategy for capturing energy from the sun by coupling light harvesting and the oxidation of water, in order to create clean hydrogen fuel. Thus a deep knowledge of the water oxidation catalysis field is essential to be able to come up with useful energy conversion devices based on sunlight and water splitting. Molecular Water Oxidation Catalysis: A Key Topic for New Sustainable Energy Conversion Schemes presents a comprehensive and state-of-the-art overview of water oxidation catalysis in homogeneous phase, describing in detail the most importan

  20. Pyrite oxidation by microbial consortia (United States)

    Bostick, B. C.; Revill, K. L.; Doyle, C.; Kendelewicz, T.; Brown, G. E.; Spormann, A. M.; Fendorf, S.


    Acid mine drainage (AMD) is formed through pyrite oxidation, which produces acidity and releases toxic metals associated with pyrite and other sulfide minerals. Microbes accelerate pyrite oxidation markedly, thereby playing a major role in the production of AMD. Here, we probe pyrite oxidation by consortia of Thiobacillus ferrooxidans and thiooxidans using surface-sensitive photoelectron spectroscopy and X-ray absorption spectroscopy and compare them with surfaces oxidized through chemical and single species cultures. Microbial oxidation resulted in the formation of distinct oxidized surface species distributed non-uniformly over the pyrite surface; consortia produced a surface both more heterogeneous and more oxidized. In contrast, chemical oxidation proceeds without the build-up of passivating oxidation products. Surface morphology was not correlated with sites of nucleation or oxidation in any obvious manner. These results demonstrate that microbial oxidation occurs through a similar mechanism to chemical oxidation, but that the presence of complex microbial communities may impact the manner by which pyrite oxidation proceeds.

  1. Catalytic process for formaldehyde oxidation (United States)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)


    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  2. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)


    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  3. Reducible oxide based catalysts (United States)

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.


    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  4. Technical review of Molten Salt Oxidation

    Energy Technology Data Exchange (ETDEWEB)


    The process was reviewed for destruction of mixed low-level radioactive waste. Results: extensive development work and scaleup has been documented on coal gasification and hazardous waste which forms a strong experience base for this MSO process; it is clearly applicable to DOE wastes such as organic liquids and low-ash wastes. It also has potential for processing difficult-to-treat wastes such as nuclear grade graphite and TBP, and it may be suitable for other problem waste streams such as sodium metal. MSO operating systems may be constructed in relatively small units for small quantity generators. Public perceptions could be favorable if acceptable performance data are presented fairly; MSO will likely require compliance with regulations for incineration. Use of MSO for offgas treatment may be complicated by salt carryover. Figs, tabs, refs.

  5. RNA modifications by oxidation

    DEFF Research Database (Denmark)

    Poulsen, Henrik E; Specht, Elisabeth; Broedbaek, Kasper


    The past decade has provided exciting insights into a novel class of central (small) RNA molecules intimately involved in gene regulation. Only a small percentage of our DNA is translated into proteins by mRNA, yet 80% or more of the DNA is transcribed into RNA, and this RNA has been found...... to encompass various classes of novel regulatory RNAs, including, e.g., microRNAs. It is well known that DNA is constantly oxidized and repaired by complex genome maintenance mechanisms. Analogously, RNA also undergoes significant oxidation, and there are now convincing data suggesting that oxidation......, and the consequent loss of integrity of RNA, is a mechanism for disease development. Oxidized RNA is found in a large variety of diseases, and interest has been especially devoted to degenerative brain diseases such as Alzheimer disease, in which up to 50-70% of specific mRNA molecules are reported oxidized, whereas...

  6. A Two-Layer Classifier with Rejection Feature based on Discrimination Projection and Minimum L1-ball Covering Model%区分性投影结合最小L1球覆盖的可拒识双层分类器

    Institute of Scientific and Technical Information of China (English)

    胡正平; 贾千文; 许成谦


    Classical classifier supposed that the test pattern must be the same class as the trainning pattern, while that maybe make error judgment in some applications such as network security biological ID recognition and medical diagnoses , because the classical classifier cann't make rejecting judgment for the existing uncooperative exceptional input pattern. A two-layer classifier with rejection feature based on discrimination projection and minimum L1-ball covering model is proposed to solve this problem. Aiming at the problem that one-class classification ignores discrimination between a given set of classes, the differential vector is defined to represent the detail information of each class, which forms into a new differential feature space. Combined with PCA-L1, a new discrimination projection called differential vector PCA-L1 is computed. Then, minimum L1-ball covering model as the decision boundary around each class is constructed. Thus the input pattem of no-object classes could be rejected hy the first decision boundary descriptor model. Finally, if a pattern ia accepted by the above L1-ball covering model, the recognition result is judged by the nearest neighbor classification model. Experiments on the UCI database, the MNIST database of handwritten digitals and the CMU AMP face expression datahase prove that the method proposed in this paper could achieve good recognition and rejection performance, and it could be applicable in many real pattern recognition fields.%经典分类模型总是假定测试样本属于训练类之一,然而在网络安全、身份识别、医学诊断等非合作模式识别中往往存在许多非训练类例外模式,这时由于分类器缺乏拒识能力,只能给出错误判决.为此,本文构造了一种基于区分性投影结合最小L1球覆盖的可拒识双层近邻分类器.该方法针对一类分类器忽略类别间区分性描述的不足,定义一种能够表征各训练类模式细节信息的差分矢量,形成

  7. Protein oxidation in aquatic foods

    DEFF Research Database (Denmark)

    Baron, Caroline P.


    The chapter discusses general considerations about protein oxidation and reviews the mechanisms involved in protein oxidation and consequences of protein oxidation on fish proteins. It presents two case studies, the first deals with protein and lipid oxidation in frozen rainbow trout......, and the second with oxidation in salted herring. The mechanisms responsible for initiation of protein oxidation are unclear, but it is generally accepted that free radical species initiating lipid oxidation can also initiate protein oxidation. The chapter focuses on interaction between protein and lipid...... oxidation. The protein carbonyl group measurement is the widely used method for estimating protein oxidation in foods and has been used in fish muscle. The chapter also talks about the impact of protein oxidation on protein functionality, fish muscle texture, and food nutritional value. Protein oxidation...

  8. Effect of magnesium in aluminum alloys on characteristics of microarc oxidation coatings

    Institute of Scientific and Technical Information of China (English)

    LIU Yao-hui; LI Song; YU Si-rong; ZHU Xian-yong; XU Bai-ming


    Microarc oxidation(MAO) coatings were prepared on the surface of aluminum alloys with different contents of magnesium. The morphologies and surface roughness of the coatings were characterized by Confocal laser scanning microscopy(CLSM). Phase and chemical composition of the MAO coatings were analyzed by X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The experimental results show that the coatings formed on different substrates have two-layer morphologies and are mainly composed of Al2O3 and Al-Si-O phases. In addition, the content of Al2O3 increases with increasing the content of magnesium. XPS results prove that magnesium from substrate indeed participates in the MAO process and is incorporated into the coating in the form of MgO. The coating formed on Al-3Mg substrate has the smallest mass loss and the lowest friction coefficient of 0.17-0.19.

  9. Design, fabrication and characterization of a double layer solid oxide fuel cell (DLFC) (United States)

    Wang, Guangjun; Wu, Xiangying; Cai, Yixiao; Ji, Yuan; Yaqub, Azra; Zhu, Bin


    A double layer solid oxide fuel cell (DLSOFC) without using the electrolyte (layer) has been designed by integrating advantages of positive electrode material of lithium ion battery(LiNi0.8Co0.15Al0.05O2) and oxygen-permeable membranes material (trace amount cobalt incorporated terbium doped ceria, TDC + Co) based on the semiconductor physics principle. Instead of using an electrolyte layer, the depletion layer between the anode and cathode served as an electronic insulator to block the electrons but to maintain the electrolyte function for ionic transport. Thus the device with two layers can realize the function of SOFC and at the same time avoids the electronic short circuiting problem. Such novel DLFC showed good performance at low temperatures, for instance, a maximum power density of 230 mWcm-2 was achieved at 500 °C. The working principle of the new device is presented.

  10. Preparation of electrolyte membranes for micro tubular solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)


    Yttria-stabilized zirconia (YSZ) micro tubular electrolyte membranes for solid oxide fuel cells (SOFCs) were prepared via the combined wet phase inversion and sintering technique. The as-derived YSZ mi- cro tubes consist of a thin dense skin layer and a thick porous layer that can serve as the electrode of fuel cells. The dense and the porous electrolyte layers have the thickness of 3-5 μm and 70-90 μm, respectively, while the inner surface porosity of the porous layer is higher than 28.1%. The two layers are perfectly integrated together to preclude the crack or flake of electrolyte film from the electrode. The presented method possesses distinct advantages such as technological simplicity, low cost and high reliability, and thus provides a new route for the preparation of micro tubular SOFCs.

  11. Highly oxidized graphene oxide and methods for production thereof

    Energy Technology Data Exchange (ETDEWEB)

    Tour, James M.; Kosynkin, Dmitry V.


    A highly oxidized form of graphene oxide and methods for production thereof are described in various embodiments of the present disclosure. In general, the methods include mixing a graphite source with a solution containing at least one oxidant and at least one protecting agent and then oxidizing the graphite source with the at least one oxidant in the presence of the at least one protecting agent to form the graphene oxide. Graphene oxide synthesized by the presently described methods is of a high structural quality that is more oxidized and maintains a higher proportion of aromatic rings and aromatic domains than does graphene oxide prepared in the absence of at least one protecting agent. Methods for reduction of graphene oxide into chemically converted graphene are also disclosed herein. The chemically converted graphene of the present disclosure is significantly more electrically conductive than is chemically converted graphene prepared from other sources of graphene oxide.

  12. Lignite oxidative desulphurization

    Institute of Scientific and Technical Information of China (English)

    Volodymyr Gunka; Serhiy Pyshyev


    The process of lignite desulphurization via its treatment by an oxidant (air or air–steam mixture) has been studied. The research objective was useful determination of steam application in oxidative lignite desulphurization. It has been proved that the water steam should be included in the oxidant composition to increase the hydrogen sulphide and combustible constituent content in the gases obtained during the processes under research. The impact of factors which affect the reactions between solid (in our case–lignite) and gaseous reagent (oxidant, i.e. air and or air–steam mixture) upon the research process has been investigated, if these reactions occur in the kinetic area. Such factors are linear rate of oxidant movement and coal grain size. The values of oxidant movement linear rate and coal grain size, which the reaction transfer from pyrite sulphur and organic content of lignite from diffusion into kinetic area occurs by, have been determined. Under these‘‘transfer’’ conditions, the values of coefficients of oxidant mass transfer (b, m/s) as well as Sherwood criteria and boiling layer differences have been calculated.

  13. Paraffin Oxidation Studies

    Directory of Open Access Journals (Sweden)

    Mrs. S. J. Purohit


    Full Text Available The oxidation of paraffin has been studied with keen interest by several workers from all over the world; as oxidation leads to the introduction of various functional groups in hydrocarbon chains. Processes involving the Oxidation of Paraffin’s in the liquid phase, using air or oxygen are of great importance to industrialized economies because of their role in converting petroleum hydrocarbon feed stocks such as alkanes, olefins and aromatics into industrial organic chemicals important in the polymer, petrochemicals ,cosmetics and detergent industries. The oxidation leads predominantly to the formation of secondary alcohols consisting of a mixture of all possible isomers with the same number of carbon atoms in the molecules as the initial hydrocarbons. The secondary alcohols which are oxidation products of paraffin exhibit excellent hydrolytic, oxidative and color stability, because of the nature of their branching. These alcohols have lower melting points than straight chain alcohols of corresponding length, while retaining their high temperature stability. The oxidation of paraffin wax to fatty acids is carried out in temperature range 110 0C- 140 0C. Paraffin oxidation which is carried out by ALFOL, Oxo-processes, are high temperature, high pressure processes which utilize expensive catalysts, making them energy intensive as well as expensive. The maximum conversion achieved yet by existing processes is 15�0for a batch time of 4 hours. A cheaper alternative in this article has been studied, in which paraffin Oxidation has been carried out in a foam reactor at moderate temperature and pressure with suitable catalyst , the output of the products is increased up to 62%.

  14. Photocatalytic Oxygenation of Substrates by Dioxygen with Protonated Manganese(III) Corrolazine. (United States)

    Jung, Jieun; Neu, Heather M; Leeladee, Pannee; Siegler, Maxime A; Ohkubo, Kei; Goldberg, David P; Fukuzumi, Shunichi


    UV-vis spectral titrations of a manganese(III) corrolazine complex [Mn(III)(TBP8Cz)] with HOTf in benzonitrile (PhCN) indicate mono- and diprotonation of Mn(III)(TBP8Cz) to give Mn(III)(OTf)(TBP8Cz(H)) and [Mn(III)(OTf)(H2O)(TBP8Cz(H)2)][OTf] with protonation constants of 9.0 × 10(6) and 4.7 × 10(3) M(-1), respectively. The protonated sites of Mn(III)(OTf)(TBP8Cz(H)) and [Mn(III)(OTf)(H2O)(TBP8Cz(H)2)][OTf] were identified by X-ray crystal structures of the mono- and diprotonated complexes. In the presence of HOTf, the monoprotonated manganese(III) corrolazine complex [Mn(III)(OTf)(TBP8Cz(H))] acts as an efficient photocatalytic catalyst for the oxidation of hexamethylbenzene and thioanisole by O2 to the corresponding alcohol and sulfoxide with 563 and 902 TON, respectively. Femtosecond laser flash photolysis measurements of Mn(III)(OTf)(TBP8Cz(H)) and [Mn(III)(OTf)(H2O)(TBP8Cz(H)2)][OTf] in the presence of O2 revealed the formation of a tripquintet excited state, which was rapidly converted to a tripseptet excited state. The tripseptet excited state of Mn(III)(OTf)(TBP8Cz(H)) reacted with O2 with a diffusion-limited rate constant to produce the putative Mn(IV)(O2(•-))(OTf)(TBP8Cz(H)), whereas the tripseptet excited state of [Mn(III)(OTf)(H2O)(TBP8Cz(H)2)][OTf] exhibited no reactivity toward O2. In the presence of HOTf, Mn(V)(O)(TBP8Cz) can oxidize not only HMB but also mesitylene to the corresponding alcohols, accompanied by regeneration of Mn(III)(OTf)(TBP8Cz(H)). This thermal reaction was examined for a kinetic isotope effect, and essentially no KIE (1.1) was observed for the oxidation of mesitylene-d12, suggesting a proton-coupled electron transfer (PCET) mechanism is operative in this case. Thus, the monoprotonated manganese(III) corrolazine complex, Mn(III)(OTf)(TBP8Cz(H)), acts as an efficient photocatalyst for the oxidation of HMB by O2 to the alcohol.

  15. Fatty Acid Oxidation Disorders (United States)

    ... acid oxidation disorders are tested for in newborn screening? The March of Dimes recommends that all babies ... in behavior Diarrhea, nausea (feeling sick to your stomach) and throwing up Drowsiness Fever Fussiness Little appetite ...


    NARCIS (Netherlands)

    Rispens, Minze T.; Zondervan, Charon; Feringa, Bernard


    Several chiral Cu(II)-complexes of cyclic amino acids catalyse the enantioselective allylic oxidation of cyclohexene to cyclohexenyl esters. Cyclohexenyl propionate was obtained in 86% yield with e.e.'s up to 61%.

  17. Cathodoluminescence of uranium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Winer, K.; Colmenares, C.; Wooten, F.


    The cathodoluminescence of uranium oxide surfaces prepared in-situ from clean uranium exposed to dry oxygen was studied. The broad asymmetric peak observed at 470 nm is attributed to F-center excitation.

  18. Markers of protein oxidation

    DEFF Research Database (Denmark)

    Headlam, Henrietta A; Davies, Michael Jonathan


    Exposure of proteins to radicals in the presence of O2 gives both side-chain oxidation and backbone fragmentation. These processes can be interrelated, with initial side-chain oxidation giving rise to backbone damage via transfer reactions. We have shown previously that alkoxyl radicals formed...... of this process depends on the extent of oxidation at C-3 compared with other sites. HO*, generated by gamma radiolysis, gave the highest total carbonyl yield, with protein-bound carbonyls predominating over released. In contrast, metal ion/H2O2 systems, gave more released than bound carbonyls, with this ratio...... modulated by EDTA. This is ascribed to metal ion-protein interactions affecting the sites of initial oxidation. Hypochlorous acid gave low concentrations of released carbonyls, but high yields of protein-bound material. The peroxyl radical generator 2,2'-azobis(2-amidinopropane) hydrochloride...

  19. Mercuric oxide poisoning (United States)

    ... of mercury salt. There are different types of mercury poisonings . This article discusses poisoning from swallowing mercuric oxide. ... Disinfectants Fungicides There have been reports of inorganic mercury poisoning from the use of skin-lightening creams. Note: ...



    L. I. IVANKIV; O. V. DZYUPYN; O.A. Balitskii


    This paper describes the oxygen adsorption properties on magnesium oxide surface. The results are compared with theoretical adsorption kinetics. Temperature and time dependences of adsorption mechanisms and chemiluminescence are discussed.

  1. Periodontal treatment decreases plasma oxidized LDL level and oxidative stress. (United States)

    Tamaki, Naofumi; Tomofuji, Takaaki; Ekuni, Daisuke; Yamanaka, Reiko; Morita, Manabu


    Periodontitis induces excessive production of reactive oxygen species in periodontal lesions. This may impair circulating pro-oxidant/anti-oxidant balance and induce the oxidation of low-density lipoprotein (LDL) in blood. The purpose of this study was to monitor circulating oxidized LDL and oxidative stress in subjects with chronic periodontitis following non-surgical periodontal treatment. Plasma levels of oxidized LDL and oxidative stress in 22 otherwise healthy non-smokers with chronic periodontitis (mean age 44.0 years) were measured at baseline and at 1 and 2 months after non-surgical periodontal treatment. At baseline, chronic periodontitis patients had higher plasma levels of oxidized LDL and oxidative stress than healthy subjects (p surgical periodontal treatment were effective in decreasing oxLDL, which was positively associated with a reduction in circulating oxidative stress.

  2. Silver(II) Oxide or Silver(I,III) Oxide? (United States)

    Tudela, David


    The often called silver peroxide and silver(II) oxide, AgO or Ag[subscript 2]O[subscript 2], is actually a mixed oxidation state silver(I,III) oxide. A thermochemical cycle, with lattice energies calculated within the "volume-based" thermodynamic approach, explain why the silver(I,III) oxide is more stable than the hypothetical silver(II) oxide.…

  3. Reduction property of rare earth oxide doped molybdenum oxide

    Institute of Scientific and Technical Information of China (English)


    Rare earth oxide doped molybdenum powders were prepared by the reduction of rare earth nitrites doped MoO3. The effect of rare earth oxide on the reduction behavior of molybdenum oxide had been studied by means of Temperature Programmed Reduction (TPR), thermal analysis, X-ray diffraction. Doping rare earth oxide in the powder could lower the reduction temperature of molybdenum oxide and decrease the particle size of molybdenum. The mechanism for the effects had been discussed in this paper.

  4. Pyrite oxidation by sulfolobus acidocaldarius

    Energy Technology Data Exchange (ETDEWEB)

    Tobita, M.; Yokozeki, M.; Nishikawa, N.; Kawakami, Y. (Institute of Research and Innovation, Kashiwa (Japan). Dept. of Biotechnology)


    Two strains of Sulfolobus acidocaldarius, a thermoacidophilic archaebacterium, were examined for their pyrite-oxidizing ability. S. acidocaldarius ATCC 33909 was shown to possess iron-oxidizing activity by ferrous sulfate oxidizing experiments, but S. acidocaldarius No. 7 did not have it. Pyrite-oxidizing rate of S. acidocaldarius ATCC 33909 was 1.6-fold higher than that of strain 7 though they had a similar level of self-oxidizing ability. These results show that the iron-oxidizing activity accelerates pyrite oxidation.

  5. Staphylococcal response to oxidative stress

    Directory of Open Access Journals (Sweden)

    Rosmarie eGaupp


    Full Text Available Staphylococci are a versatile genus of bacteria that are capable of causing acute and chronic infections in diverse host species. The success of staphylococci as pathogens is due in part to their ability to mitigate endogenous and exogenous oxidative and nitrosative stress. Endogenous oxidative stress is a consequence of life in an aerobic environment; whereas, exogenous oxidative and nitrosative stress are often due to the bacteria’s interaction with host immune systems. To overcome the deleterious effects of oxidative and nitrosative stress, staphylococci have evolved protection, detoxification, and repair mechanisms that are controlled by a network of regulators. In this review, we summarize the cellular targets of oxidative stress, the mechanisms by which staphylococci sense oxidative stress and damage, oxidative stress protection and repair mechanisms, and regulation of the oxidative stress response. When possible, special attention is given to how the oxidative stress defense mechanisms help staphylococci control oxidative stress in the host.

  6. Enargite oxidation: A review (United States)

    Lattanzi, Pierfranco; Da Pelo, Stefania; Musu, Elodia; Atzei, Davide; Elsener, Bernhard; Fantauzzi, Marzia; Rossi, Antonella


    Enargite, Cu 3AsS 4, is common in some deposit types, e.g. porphyry systems and high sulphidation epithermal deposits. It is of environmental concern as a potential source of arsenic. In this communication, we review the current knowledge of enargite oxidation, based on the existing literature and our own original data. Explicit descriptions of enargite oxidation in natural environments are scarce. The most common oxidized alteration mineral of enargite is probably scorodite, FeAsO 4.2H 2O, with iron provided most likely by pyrite, a phase almost ubiquitously associated with enargite. Other secondary minerals after enargite include arsenates such as chenevixite, Cu 2Fe 2(AsO 4) 2(OH) 4.H 2O, and ceruleite, Cu 2Al 7(AsO 4) 4.11.5H 2O, and sulphates such as brochantite, Cu 4(SO 4)(OH) 6, and posnjakite, Cu 4(SO 4)(OH) 6·H 2O. Detailed studies of enargite field alteration at Furtei, Sardinia, suggest that most alteration occurs through dissolution, as testified by the appearance of etch pits at the surface of enargite crystals. However, apparent replacement by scorodite and cuprian melanterite was observed. Bulk oxidation of enargite in air is a very slow process. However, X-ray photoelectron spectroscopy (XPS) reveals subtle surface changes. From synchrotron-based XPS it was suggested that surface As atoms react very fast, presumably by forming bonds with oxygen. Conventional XPS shows the formation, on aged samples, of a nanometer-size alteration layer with an appreciably distinct composition with respect to the bulk. Mechanical activation considerably increases enargite reactivity. In laboratory experiments at acidic to neutral pH, enargite oxidation/dissolution is slow, although it is accelerated by the presence of ferric iron and/or bacteria such as Acidithiobacillus ferrooxidans and Sulfolobus BC. In the presence of sulphuric acid and ferric iron, the reaction involves dissolution of Cu and formation of native sulphur, subsequently partly oxidized to sulphate

  7. Antibacterial activity of graphite, graphite oxide, graphene oxide, and reduced graphene oxide: membrane and oxidative stress. (United States)

    Liu, Shaobin; Zeng, Tingying Helen; Hofmann, Mario; Burcombe, Ehdi; Wei, Jun; Jiang, Rongrong; Kong, Jing; Chen, Yuan


    Health and environmental impacts of graphene-based materials need to be thoroughly evaluated before their potential applications. Graphene has strong cytotoxicity toward bacteria. To better understand its antimicrobial mechanism, we compared the antibacterial activity of four types of graphene-based materials (graphite (Gt), graphite oxide (GtO), graphene oxide (GO), and reduced graphene oxide (rGO)) toward a bacterial model-Escherichia coli. Under similar concentration and incubation conditions, GO dispersion shows the highest antibacterial activity, sequentially followed by rGO, Gt, and GtO. Scanning electron microscope (SEM) and dynamic light scattering analyses show that GO aggregates have the smallest average size among the four types of materials. SEM images display that the direct contacts with graphene nanosheets disrupt cell membrane. No superoxide anion (O(2)(•-)) induced reactive oxygen species (ROS) production is detected. However, the four types of materials can oxidize glutathione, which serves as redox state mediator in bacteria. Conductive rGO and Gt have higher oxidation capacities than insulating GO and GtO. Results suggest that antimicrobial actions are contributed by both membrane and oxidation stress. We propose that a three-step antimicrobial mechanism, previously used for carbon nanotubes, is applicable to graphene-based materials. It includes initial cell deposition on graphene-based materials, membrane stress caused by direct contact with sharp nanosheets, and the ensuing superoxide anion-independent oxidation. We envision that physicochemical properties of graphene-based materials, such as density of functional groups, size, and conductivity, can be precisely tailored to either reducing their health and environmental risks or increasing their application potentials.

  8. The oxidative coupling of methane

    Energy Technology Data Exchange (ETDEWEB)

    Helton, T.; Anthony, R.G.; Gadalla, A.M. (Texas A and M Univ., College Park, TX (US))


    In this paper the spinel phase of cobalt oxide is evaluated as a potential coupling catalyst for converting methane to C/sub 2/+ hydrocarbons. Thermodynamic calculations indicate that the Gibbs free energies for forming higher hydrocarbons using the spinel form of cobalt oxide are similar to the free energies obtained for manganese (III) oxide. The oxidative coupling of methane was performed in an oxidation-reduction cycle.

  9. Stabilized tin-oxide-based oxidation/reduction catalysts (United States)

    Jordan, Jeffrey D. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Leighty, Bradley D. (Inventor); Watkins, Anthony Neal (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor); Gulati, Suresh T. (Inventor); Summers, Jerry C. (Inventor)


    The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

  10. Erythropoietin and oxidative stress. (United States)

    Maiese, Kenneth; Chong, Zhao Zhong; Hou, Jinling; Shang, Yan Chen


    Unmitigated oxidative stress can lead to diminished cellular longevity, accelerated aging, and accumulated toxic effects for an organism. Current investigations further suggest the significant disadvantages that can occur with cellular oxidative stress that can lead to clinical disability in a number of disorders, such as myocardial infarction, dementia, stroke, and diabetes. New therapeutic strategies are therefore sought that can be directed toward ameliorating the toxic effects of oxidative stress. Here we discuss the exciting potential of the growth factor and cytokine erythropoietin for the treatment of diseases such as cardiac ischemia, vascular injury, neurodegeneration, and diabetes through the modulation of cellular oxidative stress. Erythropoietin controls a variety of signal transduction pathways during oxidative stress that can involve Janus-tyrosine kinase 2, protein kinase B, signal transducer and activator of transcription pathways, Wnt proteins, mammalian forkhead transcription factors, caspases, and nuclear factor kappaB. Yet, the biological effects of erythropoietin may not always be beneficial and may be poor tolerated in a number of clinical scenarios, necessitating further basic and clinical investigations that emphasize the elucidation of the signal transduction pathways controlled by erythropoietin to direct both successful and safe clinical care.

  11. Low thermal conductivity oxides

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Wei; Phillpot, Simon R.; Wan, Chunlei; Chernatynskiy, Aleksandr; Qu, Zhixue


    Oxides hold great promise as new and improved materials for thermal-barrier coating applications. The rich variety of structures and compositions of the materials in this class, and the ease with which they can be doped, allow the exploration of various mechanisms for lowering thermal conductivity. In this article, we review recent progress in identifying specific oxides with low thermal conductivity from both theoretical and experimental perspectives. We explore the mechanisms of lowering thermal conductivity, such as introducing structural/chemical disorder, increasing material density, increasing the number of atoms in the primitive cell, and exploiting the structural anisotropy. We conclude that further systematic exploration of oxide crystal structures and chemistries are likely to result in even further improved thermal-barrier coatings.

  12. Methanol partial oxidation reformer (United States)

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael


    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  13. Electrochemical oxidation of methylenedioxyamphetamines. (United States)

    Squella, J A; Cassels, B K; Arata, M; Bavestrello, M P; Nuñez-Vergara, L J


    Four amphetamine derivatives bearing a methylenedioxy group at positions 3 and 4 of the benzene ring and differing in their substitution at C(6) were studied by differential pulse voltammetry in aqueous media. These experiments showed a single oxidation peak for the C(6)-H, -Br and -Cl compounds, while the C(6)-NO(2) analogue was not oxidized. The oxidation peak is interpreted as due to the removal of one electron from the aromatic electrophore with formation of a radical cation stabilized by the dioxole ring. The linear relationship between the peak current and the concentration of the derivatives is appropriate for development of a quantitative method for their determination. pK' values were determined using both electrochemical and spectrophotometric methods.

  14. Crystalline mesoporous metal oxide

    Institute of Scientific and Technical Information of China (English)

    Wenbo Yue; Wuzong Zhou


    Since the discovery of many types of mesoporous silicas, such as SBA-15, KIT-6, FDU-12 and SBA-16, porous crystalline transition metal oxides, such as Cr2O3, Co3O4, In2O3, NiO, CeO2, WO3, Fe2O3 and MnO2, have been synthesized using the mesoporous silicas as hard templates. Several synthetic methods have been developed. These new porous materials have high potential applications in catalysis, Li-ion rechargeable batteries and gas sensors. This article gives a brief review of the research of porous crystals of metal oxides in the last four years.

  15. Nitric oxide supersensitivity

    DEFF Research Database (Denmark)

    Olesen, J; Iversen, Helle Klingenberg; Thomsen, L L


    in a double blind design to 17 migraine patients, 17 age and sex matched healthy controls and 9 subjects with tension-type headache. The nitroglycerin-induced headache was significantly more severe in migraine sufferers, lasted longer and fulfilled diagnostic criteria for migraine more often. We have...... previously shown a similar supersensitivity to histamine which in human cerebral arteries activates endothelial H1 receptors and causes endothelial production of nitric oxide. Migraine patients are thus supersensitive to exogenous nitric oxide from nitroglycerin as well as to endothelially produced nitric...

  16. A fully spray-coated fuel cell membrane electrode assembly using Aquivion ionomer with a graphene oxide/cerium oxide interlayer (United States)

    Breitwieser, Matthias; Bayer, Thomas; Büchler, Andreas; Zengerle, Roland; Lyth, Stephen M.; Thiele, Simon


    A novel multilayer membrane electrode assembly (MEA) for polymer electrolyte membrane fuel cells (PEMFCs) is fabricated in this work, within a single spray-coating device. For the first time, direct membrane deposition is used to fabricate a PEMFC by spraying the short-side-chain ionomer Aquivion directly onto the gas diffusion electrodes. The fully sprayed MEA, with an Aquivion membrane 10 μm in thickness, achieved a high power density of 1.6 W/cm2 for H2/air operation at 300 kPaabs. This is one of the highest reported values for thin composite membranes operated in H2/air atmosphere. By the means of confocal laser scanning microscopy, individual carbon fibers from the gas diffusion layer are identified to penetrate through the micro porous layer (MPL), likely causing a low electrical cell resistance in the range of 150 Ω cm2 through the thin sprayed membranes. By spraying a 200 nm graphene oxide/cerium oxide (GO/CeO2) interlayer between two layers of Aquivion ionomer, the impact of the electrical short is eliminated and the hydrogen crossover current density is reduced to about 1 mA/cm2. The peak power density of the interlayer-containing MEA drops only by 10% compared to a pure Aquivion membrane of similar thickness.

  17. Effect of Oxide Layer in Metal-Oxide-Semiconductor Systems

    Directory of Open Access Journals (Sweden)

    Fan Jung-Chuan


    Full Text Available In this work, we investigate the electrical properties of oxide layer in the metal-oxide semiconductor field effect transistor (MOSFET. The thickness of oxide layer is proportional to square root of oxidation time. The feature of oxide layer thickness on the growth time is consistent with the Deal-Grove model effect. From the current-voltage measurement, it is found that the threshold voltages (Vt for MOSFETs with different oxide layer thicknesses are proportional to the square root of the gate-source voltages (Vgs. It is also noted that threshold voltage of MOSFET increases with the thickness of oxide layer. It indicates that the bulk effect of oxide dominates in this MOSFET structure.

  18. Copolymerization Kinetics of Ethylene Oxide and Propylene Oxide

    Institute of Scientific and Technical Information of China (English)

    尹红; 陈志荣


    The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticparameters are obtained by numerical optimization of the kinetic model.

  19. Doped zinc oxide microspheres (United States)

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.


    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  20. Highly oxidized superconductors (United States)

    Morris, Donald E.


    Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.

  1. Oxidative Stress in Myopia

    Directory of Open Access Journals (Sweden)

    Bosch-Morell Francisco


    Full Text Available Myopia affected approximately 1.6 billion people worldwide in 2000, and it is expected to increase to 2.5 billion by 2020. Although optical problems can be corrected by optics or surgical procedures, normal myopia and high myopia are still an unsolved medical problem. They frequently predispose people who have them to suffer from other eye pathologies: retinal detachment, glaucoma, macular hemorrhage, cataracts, and so on being one of the main causes of visual deterioration and blindness. Genetic and environmental factors have been associated with myopia. Nevertheless, lack of knowledge in the underlying physiopathological molecular mechanisms has not permitted an adequate diagnosis, prevention, or treatment to be found. Nowadays several pieces of evidence indicate that oxidative stress may help explain the altered regulatory pathways in myopia and the appearance of associated eye diseases. On the one hand, oxidative damage associated with hypoxia myopic can alter the neuromodulation that nitric oxide and dopamine have in eye growth. On the other hand, radical superoxide or peroxynitrite production damage retina, vitreous, lens, and so on contributing to the appearance of retinopathies, retinal detachment, cataracts and so on. The objective of this review is to suggest that oxidative stress is one of the key pieces that can help solve this complex eye problem.

  2. Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)


    The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

  3. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz


    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  4. Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)


    The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

  5. Oxidative stress in myopia. (United States)

    Francisco, Bosch-Morell; Salvador, Mérida; Amparo, Navea


    Myopia affected approximately 1.6 billion people worldwide in 2000, and it is expected to increase to 2.5 billion by 2020. Although optical problems can be corrected by optics or surgical procedures, normal myopia and high myopia are still an unsolved medical problem. They frequently predispose people who have them to suffer from other eye pathologies: retinal detachment, glaucoma, macular hemorrhage, cataracts, and so on being one of the main causes of visual deterioration and blindness. Genetic and environmental factors have been associated with myopia. Nevertheless, lack of knowledge in the underlying physiopathological molecular mechanisms has not permitted an adequate diagnosis, prevention, or treatment to be found. Nowadays several pieces of evidence indicate that oxidative stress may help explain the altered regulatory pathways in myopia and the appearance of associated eye diseases. On the one hand, oxidative damage associated with hypoxia myopic can alter the neuromodulation that nitric oxide and dopamine have in eye growth. On the other hand, radical superoxide or peroxynitrite production damage retina, vitreous, lens, and so on contributing to the appearance of retinopathies, retinal detachment, cataracts and so on. The objective of this review is to suggest that oxidative stress is one of the key pieces that can help solve this complex eye problem.

  6. Nanostructured transition metal oxides useful for water oxidation catalysis (United States)

    Frei, Heinz M; Jiao, Feng


    The present invention provides for a composition comprising a nanostructured transition metal oxide capable of oxidizing two H.sub.2O molecules to obtain four protons. In some embodiments of the invention, the composition further comprises a porous matrix wherein the nanocluster of the transition metal oxide is embedded on and/or in the porous matrix.

  7. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram


    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  8. Staged membrane oxidation reactor system (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh


    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  9. Nitrous Oxide Micro Engines Project (United States)

    National Aeronautics and Space Administration — Nitrous Oxide Micro Engines (NOME) are a new type of nitrous oxide dissociation thruster designed to generate low levels of thrust that can be used for RCS control...


    Energy Technology Data Exchange (ETDEWEB)

    Donna L. Quach; Bruce J. Mincher; Chien M. Wai


    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO2 modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO2 and counter current stripping columns is presented.

  11. Oxidative Stress and Antioxidant Defense



    Abstract Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism and environmental factors, such as air pollutants or cigarette smoke. ROS are highly reactive molecules and can damage cell structures such as carbohydrates, nucleic acids, lipids, and proteins and alter their functions. The shift in the balance between oxidants and antioxidants in favor of oxidants is termed “oxidative stress.” Regulation of reducing and oxidizing (redox) state i...


    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P.


    A brief review of plutonium oxidation literature was conducted. The purpose of the review was to ascertain the effect of oxidation conditions on oxide morphology to support the design and operation of the PDCF direct metal oxidation (DMO) furnace. The interest in the review was due to a new furnace design that resulted in oxide characteristics that are different than those of the original furnace. Very little of the published literature is directly relevant to the DMO furnace operation, which makes assimilation of the literature data with operating conditions and data a convoluted task. The oxidation behavior can be distilled into three regimes, a low temperature regime (RT to 350 C) with a relatively slow oxidation rate that is influenced by moisture, a moderate temperature regime (350-450 C) that is temperature dependent and relies on more or less conventional oxidation growth of a partially protective oxide scale, and high temperature oxidation (> 500 C) where the metal autocatalytically combusts and oxidizes. The particle sizes obtained from these three regimes vary with the finest being from the lowest temperature. It is surmised that the slow growth rate permits significant stress levels to be achieved that help break up the oxides. The intermediate temperatures result in a fairly compact scale that is partially protective and that grows to critical thickness prior to fracturing. The growth rate in this regime may be parabolic or paralinear, depending on the oxidation time and consequently the oxide thickness. The high temperature oxidation is invariant in quiescent or nearly quiescent conditions due to gas blanketing while it accelerates with temperature under flowing conditions. The oxide morphology will generally consist of fine particles (<15 {micro}m), moderately sized particles (15 < x < 250 {micro}m) and large particles (> 250 {micro}m). The particle size ratio is expected to be < 5%, 25%, and 70% for fine, medium and large particles, respectively, for

  13. Molybdenum oxide nanowires: synthesis & properties

    Directory of Open Access Journals (Sweden)

    Liqiang Mai


    Full Text Available Molybdenum oxide nanowires have been found to show promise in a diverse range of applications, ranging from electronics to energy storage and micromechanics. This review focuses on recent research on molybdenum oxide nanowires: from synthesis and device assembly to fundamental properties. The synthesis of molybdenum oxide nanowires will be reviewed, followed by a discussion of recent progress on molybdenum oxide nanowire based devices and an examination of their properties. Finally, we conclude by considering future developments.

  14. Protein oxidation in aquatic foods

    DEFF Research Database (Denmark)

    Baron, Caroline P.


    oxidation. The protein carbonyl group measurement is the widely used method for estimating protein oxidation in foods and has been used in fish muscle. The chapter also talks about the impact of protein oxidation on protein functionality, fish muscle texture, and food nutritional value. Protein oxidation...... may not only induce quality losses but may be desirable in some type of foods, such as salted herring....

  15. Oxidants and antioxidants in disease

    DEFF Research Database (Denmark)

    Lykkesfeldt, Jens; Svendsen, Ove


    Important infectious diseases in farm animals, such as pneumonia and enteritis, are thought to be associated with the so-called oxidative stress, i.e. a chemical phenomenon involving an imbalance in the redox status of the individual animal. The specifics of oxidative stress and how it may result...... theoretically, oxidative stress should be easily prevented with antioxidants yet the use of antioxidants as therapy remains controversial. The present knowledge on oxidative stress in farm animals is the topic of this review....

  16. Self-assembled manganese oxide structures through direct oxidation

    KAUST Repository

    Zhao, Chao


    The morphology and phase of self-assembled manganese oxides during different stages of thermal oxidation were studied. Very interesting morphological patterns of Mn oxide films were observed. At the initial oxidation stage, the surface was characterized by the formation of ring-shaped patterns. As the oxidation proceeded to the intermediate stage, concentric plates formed to relax the compressive stress. Our experimental results gave a clear picture of the evolution of the structures. We also examined the properties of the structures. © 2012 Elsevier B.V.

  17. Catalytic oxidation of dimethyl ether (United States)

    Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing


    A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

  18. The aqueous chemistry of oxides

    CERN Document Server

    Bunker, Bruce C


    The Aqueous Chemistry of Oxides is a comprehensive reference volume and special topics textbook that explores all of the major chemical reactions that take place between oxides and aqueous solutions. The book highlights the enormous impact that oxide-water reactions have in advanced technologies, materials science, geochemistry, and environmental science.

  19. Oxidation of Quercetin by Myeloperoxidase


    Tatjana Momić; Jasmina Savić; Vesna Vasić


    Study of effect of myeloperoxidase on quercetin at pH 6.0 indicated quercetin oxidation via the formation of the oxidation product. The stability of quercetin and oxidation product was investigated as a function of time by using spectrophotometric and HPLC techniques. The apparent pseudo first-order rate constants were calculated and discussed.

  20. Riboflavin photosensitized oxidation of myoglobin

    DEFF Research Database (Denmark)

    Grippa, Juliana M.; de Zawadzki, Andressa; Grossi, Alberto Blak


    The reaction of the fresh meat pigment oxymyoglobin, MbFe(II)O, and its oxidized form metmyoglobin, MbFe(III), with triplet-state riboflavin involves the pigment protein, which is oxidatively cleaved or dimerized as shown by SDS-PAGE and Western blotting. The overall rate constant for oxidation...

  1. Oxide fiber targets at ISOLDE

    DEFF Research Database (Denmark)

    Köster, U.; Bergmann, U.C.; Carminati, D.


    Many elements are rapidly released from oxide matrices. Some oxide powder targets show a fast sintering, thus losing their favorable release characteristics. Loosely packed oxide fiber targets are less critical since they may maintain their open structure even when starting to fuse together at so...

  2. Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Ekerdt, J.G.


    This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.

  3. Oxidation kinetics of aluminum nitride at different oxidizing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Hou Xinmei [Metallurgical and Ecological Engineering School, University of Science and Technology Beijing, Beijing 100083 (China); Chou, K.-C. [Metallurgical and Ecological Engineering School, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail:; Zhong Xiangchong [High Temperature Ceramics Institute, Zhengzhou University, Henan Province 450052 (China); Seetharaman, Seshadri [Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm (Sweden)


    In the present work, the oxidation kinetics of AlN powder was investigated by using thermogravimetric analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experiments were carried out both in isothermal as well as non-isothermal modes under two different oxidizing atmospheres. The results showed that the oxidation reaction started at around 1100 K and the rate increased significantly beyond 1273 K forming porous aluminum oxide as the reaction product. The oxidation rate was affected by temperature and oxygen partial pressure. A distinct change in the oxidation mechanism was noticed in the temperature range 1533-1543 K which is attributed to the phase transformation in oxidation product, viz. alumina. Diffusion is the controlling step during the oxidation process. Based on the experimental data, a new model for predicting the oxidation process of AlN powder had been developed, which offered an analytic form expressing the oxidation weight increment as a function of time, temperature and oxygen partial pressure. The application of this new model to this system demonstrated that this model could be used to describe the oxidation behavior of AlN powder.

  4. Factors Affection Cr(Ⅲ) Oxidation by Manganese Oxides

    Institute of Scientific and Technical Information of China (English)



    The high oxidation ability of manganese oxides or soils was used to study effects of PH and coating on Cr(Ⅲ) oxidation,The results indicated that Cr(Ⅲ) oxidation peaked in PH 4.0-6.5,The amount and rate of Cr(Ⅲ) being oxidized by uncoated δ-MnO2 were larger than those by Fe oxide- of CaCo3-coated one.Inorganic Cr(Ⅲ) wa more easily oxidzed by MnO2 than organic complex Cr(Ⅲ) due to different surface affinities. Precipitated Cr(Ⅲ) and adsorbed Cr(Ⅲ) might be transferred onto MnO2 surface and then oxidized to Cr(Ⅵ)

  5. Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts. (United States)

    Chen, Xuxing; Li, Yunpeng; Pan, Xiaoyang; Cortie, David; Huang, Xintang; Yi, Zhiguo


    The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation.

  6. Iron oxide surfaces (United States)

    Parkinson, Gareth S.


    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  7. Manganese Oxidation by Bacteria: Biogeochemical Aspects

    Digital Repository Service at National Institute of Oceanography (India)

    Sujith, P.P.; LokaBharathi, P.A.

    Manganese is an essential trace metal that is not as readily oxidizable like iron. Several bacterial groups posses the ability to oxidize Mn effectively competing with chemical oxidation. The oxides of Mn are the strongest of the oxidants, next...

  8. Oxidative stress & male infertility. (United States)

    Makker, Kartikeya; Agarwal, Ashok; Sharma, Rakesh


    The male factor is considered a major contributory factor to infertility. Apart from the conventional causes for male infertility such as varicocoele, cryptorchidism, infections, obstructive lesions, cystic fibrosis, trauma, and tumours, a new and important cause has been identified: oxidative stress. Oxidative stress is a result of the imbalance between reactive oxygen species (ROS) and antioxidants in the body. It is a powerful mechanism that can lead to sperm damage, deformity and eventually, male infertility. This review discusses the physiological need for ROS and their role in normal sperm function. It also highlights the mechanism of production and the pathophysiology of ROS in relation to the male reproductive system and enumerate the benefits of incorporating antioxidants in clinical and experimental settings.

  9. Thin Solid Oxide Cell

    DEFF Research Database (Denmark)


    The present invention relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material, at least one metal and a catalyst...... material, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention also relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous...... cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material and a catalyst material, wherein the electrolyte material is doper zirconia, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same...

  10. Defects at oxide surfaces

    CERN Document Server

    Thornton, Geoff


    This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

  11. Thin Solid Oxide Cell

    DEFF Research Database (Denmark)


    The present invention relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material, at least one metal and a catalyst...... material, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention also relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous...... cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material and a catalyst material, wherein the electrolyte material is doper zirconia, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same...

  12. Oxidation of visbreaker bitumens

    Energy Technology Data Exchange (ETDEWEB)

    Giavarini, C.; Saporito, S.


    A series of oxidation tests was carried out on a small-scale blowing unit fed with two different visbreaker (VB) bitumens, and with two straight-run (SR) soft bitumens for reference. The purpose was to study the possibility of applying the blowing process to VB feeds, and to evaluate process kinetics and product characteristics. The results showed that industrial blowing of VB bitumens is feasible and that the rate of reaction can be expressed by a first order equation with respect to change in softening point. Production of distillate oils was quite high, especially when iron trichloride was used as a catalyst; in industrial application it is suggested that VB bitumens may be oxidized without any catalyst, the kinetics of the non-catalytic process being satisfactory. Air consumption was unsteady compared with the SR operation, and plugging of the air coil was more frequent. 20 refs., 3 figs., 3 tabs.

  13. Hemoglobin oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Croci, S.; Ortalli, I.; Pedrazzi, G. [University of Parma, Istituto di Scienze Fisiche, INFM-Udr Parma (Italy); Passeri, G. [University of Parma, Dipartimento di Medicina Interna e Scienze Biomediche (Italy); Piccolo, P. [University of Parma, Istituto di Clinica chirurgica Generale, Toracica e Vascolare (Italy)


    Venous blood obtained from healthy donors and from patients suffering from breast cancer have been treated with acetylphenylhydrazine (APH) for different time. Moessbauer spectra of the packed red cells have been recorded and compared. The largest difference occurs after 50 min of treatment with APH where the patient samples show a broad spectral pattern indicating an advanced hemoglobin oxidation. These results may have some relevance in early cancer diagnosis.

  14. Lipid oxidation induced oxidative degradation of cereal beta-glucan. (United States)

    Wang, Yu-Jie; Mäkelä, Noora; Maina, Ndegwa Henry; Lampi, Anna-Maija; Sontag-Strohm, Tuula


    In food systems, lipid oxidation can cause oxidation of other molecules. This research for the first time investigated oxidative degradation of β-glucan induced by lipid oxidation using an oil-in-water emulsion system which simulated a multi-phased aqueous food system containing oil and β-glucan. Lipid oxidation was monitored using peroxide value and hexanal production while β-glucan degradation was evaluated by viscosity and molecular weight measurements. The study showed that while lipid oxidation proceeded, β-glucan degradation occurred. Emulsions containing β-glucan, oil and ferrous ion showed significant viscosity and molecular weight decrease after 1 week of oxidation at room temperature. Elevated temperature (40°C) enhanced the oxidation reactions causing higher viscosity drop. In addition, the presence of β-glucan appeared to retard the hexanal production in lipid oxidation. The study revealed that lipid oxidation may induce the degradation of β-glucan in aqueous food systems where β-glucan and lipids co-exist.

  15. Autotrophic Biofilters for Oxidation of Nitric Oxide

    Institute of Scientific and Technical Information of China (English)

    陈建孟; 陈浚; LanceHershman; 王家德; DanielP.Y.Chang


    Carbon foam—a kind of new engineering material as packing material was adopted in three biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was developed on the surface of carbon foams using nitrite as its only nitric source. The moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize the thickness of the liquid film. The liquid phase nitrification test was conducted to determine the variability and the potential of performance among the three carbon foam biofilters. The investigation showed that during the NO2-—N inlet concentration of 200 g·L-1·min-1 to 800 g·L-1·min-1, the 24PPC (pores per centimeter) carbon foam biofilter had the greatest potential, achieving the NO2-—N removal efficiency of 94% to 98%. The 8PPC and 18PPC carbon foam biofilters achieved the NO2-—N removal efficiency of 15% to 21% and of 30% to 40%, respectively. The potential for this system to remove NO from a gas stream was shown on the basis of a steady removal efficiency of 41% to 50% which was attained for the 24PPC carbon foam biofilter at specified NO inlet concentration of 66.97 mg·m-3 to 267.86mg·m-3 and an empty-bed residence time of 3.5 min.

  16. Chromatographic study of element 104 in the system HCl/triisobutylphosphate (TBP)

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R.; Paulus, W.; Kratz, J.V.; Seibert, A.; Thoerle, P.; Zauner, S. [Mainz Univ. (Germany); Bruechle, W.; Jaeger, E.; Schaedel, M.; Schausten, B. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Schumann, D. [Technische Univ. Dresden (Germany); Eichler, B.; Jost, D.T.; Tuerler, A.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    With the Automated Rapid Chemistry Apparatus ARCA chromatic experiments have been performed using the chemical system hydrochloric acid/tributylphosphate with element 104 (Rf). The results indicate that Rf behaves more like its homolog Hf. (author) 2 figs., 5 refs.

  17. Arsenite oxidation by three types of manganese oxides

    Institute of Scientific and Technical Information of China (English)


    Oxidation of As(Ⅲ) by three types of manganese oxides and the effects of pH, ion strength and tartaric acid on the oxidation were investigated by means of chemical analysis, equilibrium redox, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Three synthesized Mn oxide minerals, birnessite, cryptomelane, and hausmarnite, which widely occur in soil and sediments, could actively oxidize As(Ⅲ) to As(Ⅴ). However, their ability in As(Ⅲ)-oxidation varied greatly depending on their structure, composition and surface properties. Tunnel structured cryptomelane exhibited the highest ability of As (Ⅲ) oxidation, followed by the layer structured birnessite and the lower oxide hausmannite. The maximum amount of As (Ⅴ) produced by the oxidation was in the order (mmol/kg) ofcryptomelane (824.2) > birnessite (480.4) > hausmannite (117.9). As pH increased from the very low value(pH 2.5), the amount of As(Ⅲ) oxidized by the tested Mn oxides was firstly decreased, then negatively peaked in pH 3.0-6.5,and eventually increased remarkably. Oxidation of As(Ⅲ) by the Mn oxides had a buffering effects on the pH variation in the solution.It is proposed that the oxidative reaction processes between As( Ⅲ ) and birnessite(or cryptomelane) are as follows: (1) at lower pH condition: (MnO2)x + H3AsO3 + 0.5H+=0.5H2AsO4- + 0.5HAsO42- +Mn2++ (MnO2)x-1 + H2O; (2) at higher pH condition: (MnO2)x +cryptomelane decreased and was negatively correlated with ion strength. However, ion strength had little influence on As (Ⅲ) oxidation by the hausmannite. The presence of tartaric acid promoted oxidation of As(Ⅲ) by birnessite. As for cryptomelane and hausmannite, the same effect was observed when the concentration of tartaric acid was below 4 mmol/L, otherwise the oxidized As(Ⅲ)decreased. These findings are of great significance in improving our understanding of As geochemical cycling and controlling As contamination.

  18. The competing oxide and sub-oxide formation in metal-oxide molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Patrick; Bierwagen, Oliver [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)


    The hetero-epitaxial growth of the n-type semiconducting oxides β-Ga{sub 2}O{sub 3}, In{sub 2}O{sub 3}, and SnO{sub 2} on c- and r-plane sapphire was performed by plasma-assisted molecular beam epitaxy. The growth-rate and desorbing flux from the substrate were measured in-situ under various oxygen to metal ratios by laser reflectometry and quadrupole mass spectrometry, respectively. These measurements clarified the role of volatile sub-oxide formation (Ga{sub 2}O, In{sub 2}O, and SnO) during growth, the sub-oxide stoichiometry, and the efficiency of oxide formation for the three oxides. As a result, the formation of the sub-oxides decreased the growth-rate under metal-rich growth conditions and resulted in etching of the oxide film by supplying only metal flux. The flux ratio for the exclusive formation of the sub-oxide (e.g., the p-type semiconductor SnO) was determined, and the efficiency of oxide formation was found to be the highest for SnO{sub 2}, somewhat lower for In{sub 2}O{sub 3}, and the lowest for Ga{sub 2}O{sub 3}. Our findings can be generalized to further oxides that possess related sub-oxides.

  19. Neighboring amide participation in thioether oxidation: relevance to biological oxidation. (United States)

    Glass, Richard S; Hug, Gordon L; Schöneich, Christian; Wilson, George S; Kuznetsova, Larisa; Lee, Tang-man; Ammam, Malika; Lorance, Edward; Nauser, Thomas; Nichol, Gary S; Yamamoto, Takuhei


    To investigate neighboring amide participation in thioether oxidation, which may be relevant to brain oxidative stress accompanying beta-amyloid peptide aggregation, conformationally constrained methylthionorbornyl derivatives with amido moieties were synthesized and characterized, including an X-ray crystallographic study of one of them. Electrochemical oxidation of these compounds, studied by cyclic voltammetry, revealed that their oxidation peak potentials were less positive for those compounds in which neighboring group participation was geometrically possible. Pulse radiolysis studies provided evidence for bond formation between the amide moiety and sulfur on one-electron oxidation in cases where the moieties are juxtaposed. Furthermore, molecular constraints in spiro analogues revealed that S-O bonds are formed on one-electron oxidation. DFT calculations suggest that isomeric sigma*(SO) radicals are formed in these systems.

  20. Partial Oxidation of Methane Over the Perovskite Oxides

    Institute of Scientific and Technical Information of China (English)


    Ba0.sSr0.5Co0.8Fe0.2O3-δ and Ba0.5Sr0.5Co0.8Ti0.2O3-δ oxides were synthesized by a combined EDTA-citrate complexing method. The catalytic behavior of these two oxides with the perovskite structure was studied during the reaction of methane oxidation. The pre-treatment with methane has different effect on the catalytic activities of both the oxides. The methane pre-treatment has not resulted in the change of the catalytic activity of BSCFO owing to its excellent reversibility of the perovskite structure resulting from the excellent synergistic interaction between Co and Fe in the oxide. However, the substitution with Ti on Fe-site in the lattice makes the methane pre-treatment have an obvious influence on the activity of the formed BSCTO oxide.