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Sample records for assisted reaction route

  1. A novel microwave synthesis of calcium hydroxyapatite. Optimisation and investigation of a microwave assisted reaction route

    International Nuclear Information System (INIS)

    Hydroxyapatite is a bioactive calcium phosphate used in non-load bearing applications, such as space-filling in maxillofacial reconstruction. As a coating, hydroxyapatite is used on load-bearing orthopaedic metal prostheses to improve fixation and/or biocompatibility. Conventional synthesis processes for the production of hydroxyapatite are time-consuming and labour-intensive. Microwave irradiation was investigated as a means to enhance the synthesis reaction using calcium hydroxide (Ca(OH)2) and orthophosphoric acid (H3PO4) as reactants. An initial set of reactions indicated the feasibility of the microwave synthesis route. Optimisation reactions were then performed followed by investigation sets of reactions. Parameters such as microwave power, irradiation time, and reactant concentrations were varied. Using 0.5M Ca(OH)2 and 0.3M H3PO4, a phase-pure hydroxyapatite powder with a stoichiometric molar Ca/P ratio of 1.67 was produced in 60 seconds at 450W and 2.45GHz. The microwave synthesis reaction only reached completion when conducted at moderate temperatures (20-30 deg C). At approximately 5 deg C and at temperatures in excess of 45 deg C, the microwave reaction did not reach completion. A preliminary kinetic study of the microwave reaction revealed a 3 to 4-fold increase in the activation energy of the microwave reaction compared to a non-microwave equivalent. The Arrhenius pro-exponential factor was half that of the non-microwave reaction. The kinetic data suggests two energetically different pathways for the reaction between Ca(OH)2 and H3PO4. A fast high-energy pathway is powered by microwave irradiation, while a slow low-energy pathway prevails under conventional synthesis conditions. Microwave synthesis has potential for scaling-up to commercial amounts of hydroxyapatite powder production. Control over the product powder morphology may be achieved with further optimisation. (author)

  2. A novel microwave synthesis of calcium hydroxyapatite. Optimisation and investigation of a microwave assisted reaction route

    CERN Document Server

    Zawahreh, Y

    2001-01-01

    Hydroxyapatite is a bioactive calcium phosphate used in non-load bearing applications, such as space-filling in maxillofacial reconstruction. As a coating, hydroxyapatite is used on load-bearing orthopaedic metal prostheses to improve fixation and/or biocompatibility. Conventional synthesis processes for the production of hydroxyapatite are time-consuming and labour-intensive. Microwave irradiation was investigated as a means to enhance the synthesis reaction using calcium hydroxide (Ca(OH) sub 2) and orthophosphoric acid (H sub 3 PO sub 4) as reactants. An initial set of reactions indicated the feasibility of the microwave synthesis route. Optimisation reactions were then performed followed by investigation sets of reactions. Parameters such as microwave power, irradiation time, and reactant concentrations were varied. Using 0.5M Ca(OH) sub 2 and 0.3M H sub 3 PO sub 4 , a phase-pure hydroxyapatite powder with a stoichiometric molar Ca/P ratio of 1.67 was produced in 60 seconds at 450W and 2.45GHz. The microw...

  3. Quantum chemistry-assisted synthesis route development

    International Nuclear Information System (INIS)

    We have been investigating “quantum chemistry-assisted synthesis route development” using in silico screenings and applied the method to several targets. Another example was conducted to develop synthesis routes for a urea derivative, namely 1-(4-(trifluoromethyl)-2-oxo-2H-chromen-7-yl)urea. While five synthesis routes were examined, only three routes passed the second in silico screening. Among them, the reaction of 7-amino-4-(trifluoromethyl)-2H-chromen-2-one and O-methyl carbamate with BF3 as an additive was ranked as the first choice for synthetic work. We were able to experimentally obtain the target compound even though its yield was as low as 21 %. The theoretical result was thus consistent with that observed. The summary of transition state data base (TSDB) is also provided. TSDB is the key to reducing time of in silico screenings

  4. Quantum chemistry-assisted synthesis route development

    Energy Technology Data Exchange (ETDEWEB)

    Hori, Kenji; Sumimoto, Michinori [Graduate School of Science and Engineering, Yamaguchi University, Tokiwadai, Ube, Yamaguchi 755-8611 (Japan); Murafuji, Toshihiro [Graduate School of Medicine, Yamaguchi University, Yamaguchi, Yamaguchi 753-8512 (Japan)

    2015-12-31

    We have been investigating “quantum chemistry-assisted synthesis route development” using in silico screenings and applied the method to several targets. Another example was conducted to develop synthesis routes for a urea derivative, namely 1-(4-(trifluoromethyl)-2-oxo-2H-chromen-7-yl)urea. While five synthesis routes were examined, only three routes passed the second in silico screening. Among them, the reaction of 7-amino-4-(trifluoromethyl)-2H-chromen-2-one and O-methyl carbamate with BF{sub 3} as an additive was ranked as the first choice for synthetic work. We were able to experimentally obtain the target compound even though its yield was as low as 21 %. The theoretical result was thus consistent with that observed. The summary of transition state data base (TSDB) is also provided. TSDB is the key to reducing time of in silico screenings.

  5. Quantum chemistry-assisted synthesis route development

    Science.gov (United States)

    Hori, Kenji; Sumimoto, Michinori; Murafuji, Toshihiro

    2015-12-01

    We have been investigating "quantum chemistry-assisted synthesis route development" using in silico screenings and applied the method to several targets. Another example was conducted to develop synthesis routes for a urea derivative, namely 1-(4-(trifluoromethyl)-2-oxo-2H-chromen-7-yl)urea. While five synthesis routes were examined, only three routes passed the second in silico screening. Among them, the reaction of 7-amino-4-(trifluoromethyl)-2H-chromen-2-one and O-methyl carbamate with BF3 as an additive was ranked as the first choice for synthetic work. We were able to experimentally obtain the target compound even though its yield was as low as 21 %. The theoretical result was thus consistent with that observed. The summary of transition state data base (TSDB) is also provided. TSDB is the key to reducing time of in silico screenings.

  6. Malic acid assisted precursor route to hierarchical structured nickel oxide

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haizhen [Zhejiang California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang (China); Qian, Yitai [Hefei National Laboratory for Physical Science at Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui (China)

    2010-05-15

    A novel malic acid assisted precursor route to prepare NiO materials with novel hierarchical structures has been investigated in this work. The Ni-based precursors can be synthesized by a malic acid-assisted hydrothermal route, which have been characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA). NiO materials can be prepared via the thermal treatment of the precursor in ambient atmosphere. The XRD, SEM, Energy dispersive X-ray spectroscopy (EDS) and UV-Vis spectroscopy of the NiO materials were also examined. The effects of the reaction conditions, such as the reaction temperature, the quantity of the raw materials on the morphologies of the precursors were discussed, which indicates that it is an effective method to synthesize NiO materials with different hierarchical structures. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Microwave-assisted route for synthesis of nanosized metal oxides

    Directory of Open Access Journals (Sweden)

    Arunkumar Lagashetty et al

    2007-01-01

    Full Text Available Microwave-assisted route for the synthesis of nanomaterials has gained importance in the field of synthetic technology because of its faster, cleaner and cost effectiveness than the other conventional and wet chemical methods for the preparation of metal oxide nanoparticles. In the present work, synthesis of metal oxide nanoparticles viz., γ-Fe2O3, NiO, ZnO, CuO and Co-γ-Fe2O3 were carried out by microwave-assisted route through the thermal decomposition of their respective metal oxalate precursors employing polyvinyl alcohol as a fuel. The metal oxide nanoparticles are then characterized for their size and γ to α (in γ-Fe2O3 transition and structure by employing powder X-ray diffraction (XRD pattern, high-temperature X-ray diffraction (HTXRD pattern and Fourier transform infrared (FT-IR spectral studies. The morphology of the samples ranged from nanorods to irregular-shaped particles for different metal oxide samples on the basis of scanning electron microscopy and transmission electron microscopy images. Frequency-dependent dielectric study of the ferrite samples (γ-Fe2O3 and Co-Fe2O3 showed a similar behaviour, where the dielectric constant decreased rapidly with increase in frequency. Possible explanation for this behaviour is given.

  8. Biomolecule-assisted route to prepare titania mesoporous hollow structures.

    Science.gov (United States)

    Ding, Shangjun; Wang, Yaoming; Hong, Zhanglian; Lü, Xujie; Wan, Dongyun; Huang, Fuqiang

    2011-10-01

    Amino acids, as a particularly important type of biomolecules, have been used as multifunctional templates to intelligently construct mesoporous TiO(2) hollow structures through a simple solvothermal reaction. The structure-directing behaviors of various amino acids were systematically investigated, and it was found that these biomolecules possess the general capability to assist mesoporous TiO(2) hollow-sphere formation. At the same time, the nanostructures of the obtained TiO(2) are highly dependent on the isoelectric points (pI) of amino acids. Their molecular-structure variations can lead to pI differences and significantly influence the final TiO(2) morphologies. Higher-pI amino acids (e.g., L-lysine and L-arginine) have better structure-directing abilities to generate nanosheet-assembled hollow spheres and yolk/shell structures. The specific morphologies and mesopore size of these novel hollow structures can also be tuned by adjusting the titanium precursor concentration. Heat treatment in air and vacuum was further conducted to transform the as-prepared structures to porous nanoparticle-assembled hollow TiO(2) and TiO(2)/carbon nanocomposites, which may be potentially applied in the fields of photocatalysts, dye-sensitized solar cells, and Li batteries. This study provides some enlightenment on the design of novel templates by taking advantage of biomolecules. PMID:21882272

  9. Mobility-Assisted on-Demand Routing Algorithm for MANETs in the Presence of Location Errors

    Directory of Open Access Journals (Sweden)

    Trung Kien Vu

    2014-01-01

    Full Text Available We propose a mobility-assisted on-demand routing algorithm for mobile ad hoc networks in the presence of location errors. Location awareness enables mobile nodes to predict their mobility and enhances routing performance by estimating link duration and selecting reliable routes. However, measured locations intrinsically include errors in measurement. Such errors degrade mobility prediction and have been ignored in previous work. To mitigate the impact of location errors on routing, we propose an on-demand routing algorithm taking into account location errors. To that end, we adopt the Kalman filter to estimate accurate locations and consider route confidence in discovering routes. Via simulations, we compare our algorithm and previous algorithms in various environments. Our proposed mobility prediction is robust to the location errors.

  10. Nanocrystalline spinel ferrites by solid state reaction route

    Indian Academy of Sciences (India)

    T K Kundu; S Mishra

    2008-06-01

    Nanostructured NiFe2O4, MnFe2O4 and (NiZn)Fe2O4 were synthesized by aliovalent ion doping using conventional solid-state reaction route. With the doping of Nb2O5, the size of NiFe2O4 is reduced down to 33 nm. Similarly, nanostructured manganese ferrites (MnFe2O4) with diameters in the range of 45–30 nm were synthesized by Ti4+ ion doping. Particle diameters in all the specimens are found to decrease with increasing dopant content. The substitution of Nb5+ or Ti3+ ions essentially breaks up the ferrimagnetically active oxygen polyhedra. This created nanoscale regions of ferrites. Saturation magnetization and coercive field show a strong dependence on the size of the ferrite grains. Superparamagnetic behaviour is observed from the Mössbauer spectra of nanostructured NiFe2O4, if the particle size is reduced to 30 nm. Zero field cooled and field cooled curves from 30 nm sized MnFe2O4 particles showed a peak at B (∼ 125 K), typical of superparamagnetic blocking temperature. These results are explained in terms of core/shell structure of the materials. The d.c. resistivity of the doped specimens decreases by atleast five orders of magnitude compared to pure sample. This is ascribed to the presence of an interfacial amorphous phase between the sites.

  11. Synthesis of hierarchical CuS flower-like submicrospheres via an ionic liquid-assisted route

    Indian Academy of Sciences (India)

    Lihua Wang; Chao Xu; Dingbing Zou; Hao Luo; Taokai Ying

    2008-12-01

    A facile, ionic liquid-assisted route was developed to synthesize hierarchical CuS flower-like submicrospheres at 80°C for 24 h. The method was based on a reaction between CuCl2 and thioacetamide (TAA) in aqueous solution with using ionic liquid 1--butyl-3-methylimidazolium chloride ([BMIM]Cl) as an assisted agent. The chemical composition, morphology and size of CuS product were characterized by XRD, SEM and TEM. The result shows that the as-prepared CuS consists of flowery spheres with a diameter of 0.6 ∼ 1.0 m, and these submicrospheres are, in fact, built by numerous nanoflakes with a thickness of 10 ∼ 20 nm. The optical property of CuS product was examined by UV-Vis. In general, we suggested an ecologically and environmentally friendly route for the syntheses of hierarchical metal chalcogenides structures in this paper.

  12. Atmospheric Pressure Microwave Assisted Heterogeneous Catalytic Reactions

    Directory of Open Access Journals (Sweden)

    Farid Chemat

    2007-07-01

    Full Text Available The purpose of the study was to investigate microwave selective heatingphenomena and their impact on heterogeneous chemical reactions. We also present a toolwhich will help microwave chemists to answer to such questions as “My reaction yields90% after 7 days at reflux; is it possible to obtain the same yield after a few minutes undermicrowaves?” and to have an approximation of their reactions when conducted undermicrowaves with different heterogeneous procedures. This model predicting reactionkinetics and yields under microwave heating is based on the Arrhenius equation, inagreement with experimental data and procedures.

  13. Preparation of hollow carbon nanospheres at low temperature via new reaction route

    International Nuclear Information System (INIS)

    Hollow carbon nanospheres were obtained at 200oC via a new reaction route, by using magnesium, hexachloroethane and aluminum trichloride as starting materials and benzene as solvent. The products were characterized with X-ray diffraction pattern, transmission electron microscope, high-resolution transmission electron microscope images and Raman spectrum. The reaction conditions are easy to be maintained and controlled. They may provide a new method to produce other carbonaceous materials. A possible mechanism of reaction was proposed

  14. Influence of interface reactions on the YBCO films grown by fluorine-free solution route

    DEFF Research Database (Denmark)

    Zhao, Yue; Wu, Wei; Tang, Xiao;

    2015-01-01

    Fabrication of full-stacked coated conductors by all-chemical-solution routes exhibit a great potential in view of further reducing the cost and increasing the throughput for industrialization. Growth of YBa2Cu3O7−x (YBCO) superconducting films by fluorine-free metal organic deposition routes (FF...... properties studies reveal that the interface reactions between the YBCO-Ag film and the CLO cap layer play an essential role on the nucleation and growth of YBCO-Ag films from the FF solution. Weak texture caused by serious interface reactions at high growth temperature is the main explanations for the poor...

  15. Nanostructured palladium tailored via carbonyl chemical route towards oxygen reduction reaction

    International Nuclear Information System (INIS)

    Graphical Abstract: Mass-depending morphologies of nanostructured Palladium obtained via the carbonyl chemical route. Display Omitted -- Highlights: •Mass-depending morphology was observed in nanostructured palladium supported on carbon prepared by the carbonyl chemical route. •The Morphological effect of carbon supported Pd was investigated towards ORR. -- Abstract: Carbon supported palladium nanostructures were synthesized via the carbonyl chemical route. Compared with nanostructured platinum, prepared via carbonyl chemical route, Pd nanomaterials showed mass-loading morphology, whereas particle size and morphology of Pt nanostructures was constant. The oxygen reduction reaction (ORR) on nanostructured Pd, with different morphology in both acid and alkaline medium was investigated. A relationship, based on X-ray diffraction structural analysis pattern, transmission electron microscope, with the Pd morphological effect on ORR activity was identified

  16. A facile route to synthesize endurable mesopore containing ZSM-5 catalyst for methanol to propylene reaction.

    Science.gov (United States)

    Sun, Chao; Du, Junming; Liu, Jian; Yang, Yisu; Ren, Nan; Shen, Wei; Xu, Hualong; Tang, Yi

    2010-04-21

    A novel route is proposed for the preparation of mesopore containing zeolite ZSM-5 via in situ hydrothermal treatment of a solution containing alkali-dissolved SBA-15 containing carbonized surfactant P123 in the mesopores; it exhibited prominent stability enhancement for methanol to propylene reaction. PMID:20461876

  17. Multifaceted and route-controlled "click" reactions based on vapor-deposited coatings.

    Science.gov (United States)

    Sun, Ting-Pi; Tai, Ching-Heng; Wu, Jyun-Ting; Wu, Chih-Yu; Liang, Wei-Chieh; Chen, Hsien-Yeh

    2016-01-26

    "Click" reactions provide precise and reliable chemical transformations for the preparation of functional architectures for biomaterials and biointerfaces. The emergence of a multiple-click reaction strategy has paved the way for a multifunctional microenvironment with orthogonality and precise multitasking that mimics nature. We demonstrate a multifaceted and route-controlled click interface using vapor-deposited functionalized poly-para-xylylenes. Distinctly clickable moieties of ethynyl and maleimide were introduced into poly-para-xylylenes in one step via a chemical vapor deposition (CVD) copolymerization process. The advanced interface coating allows for a double-click route with concurrent copper(i)-catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) and the thiol-maleimide click reaction. Additionally, double-click reactions can also be performed in a cascade manner by controlling the initiation route to enable the CuAAC and/or thiol-yne reaction using a mono-functional alkyne-functionalized poly-para-xylylene. The use of multifaceted coatings to create straightforward and orthogonal interface properties with respect to protein adsorption and cell attachment is demonstrated and characterized. PMID:26650976

  18. Quantum Molecular Dynamics Simulations of Nanotube Tip Assisted Reactions

    Science.gov (United States)

    Menon, Madhu

    1998-01-01

    In this report we detail the development and application of an efficient quantum molecular dynamics computational algorithm and its application to the nanotube-tip assisted reactions on silicon and diamond surfaces. The calculations shed interesting insights into the microscopic picture of tip surface interactions.

  19. Synthesis and Characterization of Yttrium Doped Nano-zirconia by a Cationic Surfactant-assisted Route

    Institute of Scientific and Technical Information of China (English)

    YU Jian-Chang; HU Shen-Wei

    2006-01-01

    Recently, more and more interest has been focused on zirconia for its unique characteristics. In this paper, via the preceding preparation technique, yttrium can be successfully incorporated into nano-zirconia by a cationic surfactant-assisted route. The methods of XRD, TEM, EDS, Uv-vis and N2 adsorption-desorption are adopted to characterize the synthesized samples. The results show that the yttrium has been successfully incorporated into the zirconia lattice, and the thermal stability of yttrium doped zirconia has been enhanced remarkably.

  20. Cd–cysteine precursor nanowire templated microwave-assisted transformation route to CdS nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao-Lin, E-mail: liu_x_l@sina.cn [School of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000 (China); Zhu, Ying-Jie [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Qian; Li, Zhi-Feng; Yang, Bin [School of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000 (China)

    2012-12-15

    Graphical abstract: Cadmium sulfide polycrystalline nanotubes have been successfully synthesized by microwave-assisted transformation method using Cd–cysteine precursor nanowires as the source material and template in ethylene glycol at 160 °C or ethanol at 60 °C. Display Omitted Highlights: ► Cd–cysteine precursor nanowires were successfully synthesized in alkaline solution. ► CdS nanotubes were prepared by templated microwave-assisted transformation method. ► CdS nanotubes can well duplicate the size and morphology of precursor nanowires. ► This method has the advantages of the simplicity and low cost. -- Abstract: We report the Cd–cysteine precursor nanowire templated microwave-assisted transformation route to CdS nanotubes. In this method, the Cd–cysteine precursor nanowires are synthesized using CdCl{sub 2}·2.5H{sub 2}O, L-cysteine and ethanolamine in water at room temperature. The Cd–cysteine precursor nanowires are used as the source material and template for the subsequent preparation of CdS nanotubes by a microwave-assisted transformation method using ethylene glycol or ethanol as the solvent. This method has the advantages of the simplicity and low cost, and may be extended to the synthesis of nanotubes of other compounds. The products are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  1. A new sonication-assisted ionic liquid-based route to microcrystals of lanthanide fluorides and their photoluminescent properties

    International Nuclear Information System (INIS)

    Highlights: • Microcrystals of lanthanide fluorides were prepared by sonication-assisted IL-based route. • It is a fast, simple, green and mild method to get lanthanide fluoride microcrystals. • The microcrystals are uniform, monodisperse, well-shaped and phase-pure. • IL served as reaction medium, fluoride source as well as template. • Sonication helped to accelerate reaction and get monodisperse uniform microcrystals. - Abstract: We introduce an ionic liquid-based method for the synthesis of uniform lanthanide fluoride microcrystals with the assistance of a sonication-accelerated reaction system. It is a fast, simple and mild process to get uniform monodisperse spherical lanthanide fluoride microcrystals in large scale. Homogeneous precipitation in a biphasic system of ethanol solution of lanthanide nitrates and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] led to the uniform LnF3 microcrystals. The method was applied to the preparation of pure LnF3 (Ln = La, Ce, Pr, Nd) and Eu3+-doped LaF3, Tb3+-doped CeF3. SEM images indicated highly uniform cotton-like spherical microcrystals were obtained. HRTEM image indicated that the microcrystals were aggregated by nanocrystals of 6–10 nm due to agglomeration effect of the ionic liquid. The uniformity and dispersility of LaF3 decreased with the increasing of the molar ratio of [C4mim][PF6] to La(NO3)3·6H2O. Diameter of the microcrystal decreased from La to Nd. Photoluminescence properties of Eu3+-doped LaF3 and Tb3+-doped CeF3 were also studied

  2. Recovery of uranium from fluoride matrix by solid state reaction routes

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhury, S.; Singh Mudher, K.D. E-mail: kdsingh@apsara.barc.ernet.in; Venugopal, V

    2003-11-01

    A simple method is developed for the separation and recovery of uranium in a CaF{sub 2} and MgF{sub 2} matrix, employing a solid state reaction route, heating the uranium slag-composition mixture with (NH{sub 4}){sub 2}SO{sub 4}. Reactions of a synthetic slag-composition mixture with (NH{sub 4}){sub 2}SO{sub 4} above 350 deg. C formed sulfate compounds of uranium, calcium and magnesium. The sulfates of uranium were separated by dissolving in dilute acid. Reactions were monitored by TG-DTA analysis. Products formed at different temperatures were characterised by X-ray powder diffraction. Quantitative analysis of the products was achieved using redox titrimetry. By this method about 95% of the uranium present could be recovered from synthetic mixtures.

  3. Synthesis of flower-like Boehmite (γ-AlOOH) via a one-step ionic liquid-assisted hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhe, E-mail: tangzhe1983@163.com; Liang, Jilei, E-mail: liangjilei_httplan@126.com; Li, Xuehui, E-mail: lxhhmx@163.com; Li, Jingfeng, E-mail: dzcljf@126.com; Guo, Hailing; Liu, Yunqi, E-mail: liuyq@upc.edu.cn; Liu, Chenguang, E-mail: cgliu@upc.edu.cn

    2013-06-01

    A simple and novel synthesis process, one-step ionic liquid-assisted hydrothermal synthesis route, has been developed in the work to synthesize Bohemithe (γ-AlOOH) with flower-like structure. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Ionic liquid [Omim]{sup +}Cl{sup −}, as a template, plays an important role in the morphology and pore structure of the products due to its strong interactions with reaction particles. With the increase in the dosage of ionic liquid [Omim]{sup +}Cl{sup −}, the morphology of the γ-AlOOH was changed from initial bundles of nanosheets (without ionic liquid) into final well-developed monodispersed 3D flower-like architectures ([Omim]{sup +}Cl{sup −}=72 mmol). The pore structure was also altered gradually from initial disordered slit-like pore into final relatively ordered ink-bottle pore. Furthermore, the proposed formation mechanism and other influencing factors such as reaction temperature and urea on formation and morphology of the γ-AlOOH have also been investigated. - Graphical abstract: The flower-like γ-AlOOH architectures composed by nanosheets with narrow size distribution (1.6–2.2 μm) and uniform pore size (6.92 nm) have been synthesized via a one-step ionic liquid-assisted hydrothermal route. - Highlights: • The γ-AlOOH microflowers were synthesized via an ionic liquid-assisted hydrothermal route. • Ionic liquid plays an important role on the morphology and porous structure of the products. • Ionic liquid can be easily removed from the products and reused in recycling experiments. • A “aggregation–recrystallization–Ostwald Ripening“formation mechanism may occur.

  4. Synthesis of flower-like Boehmite (γ-AlOOH) via a one-step ionic liquid-assisted hydrothermal route

    International Nuclear Information System (INIS)

    A simple and novel synthesis process, one-step ionic liquid-assisted hydrothermal synthesis route, has been developed in the work to synthesize Bohemithe (γ-AlOOH) with flower-like structure. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Ionic liquid [Omim]+Cl−, as a template, plays an important role in the morphology and pore structure of the products due to its strong interactions with reaction particles. With the increase in the dosage of ionic liquid [Omim]+Cl−, the morphology of the γ-AlOOH was changed from initial bundles of nanosheets (without ionic liquid) into final well-developed monodispersed 3D flower-like architectures ([Omim]+Cl−=72 mmol). The pore structure was also altered gradually from initial disordered slit-like pore into final relatively ordered ink-bottle pore. Furthermore, the proposed formation mechanism and other influencing factors such as reaction temperature and urea on formation and morphology of the γ-AlOOH have also been investigated. - Graphical abstract: The flower-like γ-AlOOH architectures composed by nanosheets with narrow size distribution (1.6–2.2 μm) and uniform pore size (6.92 nm) have been synthesized via a one-step ionic liquid-assisted hydrothermal route. - Highlights: • The γ-AlOOH microflowers were synthesized via an ionic liquid-assisted hydrothermal route. • Ionic liquid plays an important role on the morphology and porous structure of the products. • Ionic liquid can be easily removed from the products and reused in recycling experiments. • A “aggregation–recrystallization–Ostwald Ripening“formation mechanism may occur

  5. Scalable route to CH3NH3PbI3 perovskite thin films by aerosol assisted chemical vapour deposition

    OpenAIRE

    Bhachu, D. S.; Scanlon, D. O.; Saban, E. J.; Bronstein, H.; Parkin, I. P.; Carmalt, C. J.; Palgrave, R. G.

    2015-01-01

    Methyl-ammonium lead iodide is the archetypal perovskite solar cell material. Phase pure, compositionally uniform methyl-ammonium lead iodide thin films on large glass substrates were deposited using ambient pressure aerosol assisted chemical vapour deposition. This opens up a route to efficient scale up of hybrid perovskite film growth towards industrial deployment.

  6. Phase-controlled synthesis of Cu{sub 2}ZnSnS{sub 4} powders via the microwave-assisted solvothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Hsung; Das, Subrata; Yang, Che-Yuan; Sung, Jen-Cheng; Lu, Chung-Hsin, E-mail: chlu@ntu.edu.tw

    2015-05-25

    Highlights: • Cu{sub 2}ZnSnS{sub 4} powders were prepared via the microwave-assisted solvothermal route. • Kesterite and wurtzite phase were formed via adjusting the amount of ethylenediamine. • Cu{sub 2}S was reacted with constituent ions and hydrogen sulfide ions to form Cu{sub 2}ZnSnS{sub 4}. • Single-phased kesterite and wurtzite Cu{sub 2}ZnSnS{sub 4} powders were derived in this study. - Abstract: Cu{sub 2}ZnSnS{sub 4} was successfully prepared via the microwave-assisted solvothermal route at the reaction temperature as low as 180 °C. In comparison with the conventional solution process for preparing Cu{sub 2}ZnSnS{sub 4} powders, the reaction time was significantly reduced to 1 h, and the preparation procedures were simplified with the incorporation of microwave irradiation technique. The mobility of ions and dipoles are suggested to have been accelerated via the microwave, thereby enhancing the reaction rates. Kesterite and wurtzite Cu{sub 2}ZnSnS{sub 4} powders were formed via adjusting the volume fraction of ethylenediamine in the microwave-solvothermal process. The amount of ethylenediamine affected the morphology of the derived powders due to the selective passivation of ethylenediamine on Cu{sub 2}ZnSnS{sub 4}. The microscopic analysis revealed that the samples prepared with high ethylenediamine concentrations had large particle sizes. The enhanced grain size reduced the surface recombination and increased the photoluminescence intensity of Cu{sub 2}ZnSnS{sub 4} particles. During the microwave-assisted solvothermal process, Cu{sub 2}S was formed first and reacted with the constituent ions and hydrogen sulfide ions to form Cu{sub 2}ZnSnS{sub 4} powders.

  7. Aerosol assisted chemical vapor deposition using nanoparticle precursors: a route to nanocomposite thin films.

    Science.gov (United States)

    Palgrave, Robert G; Parkin, Ivan P

    2006-02-01

    Gold nanoparticle and gold/semiconductor nanocomposite thin films have been deposited using aerosol assisted chemical vapor deposition (CVD). A preformed gold colloid in toluene was used as a precursor to deposit gold films onto silica glass. These nanoparticle films showed the characteristic plasmon absorption of Au nanoparticles at 537 nm, and scanning electron microscopic (SEM) imaging confirmed the presence of individual gold particles. Nanocomposite films were deposited from the colloid concurrently with conventional CVD precursors. A film of gold particles in a host tungsten oxide matrix resulted from co-deposition with [W(OPh)(6)], while gold particles in a host titania matrix resulted from co-deposition with [Ti(O(i)Pr)(4)]. The density of Au nanoparticles within the film could be varied by changing the Au colloid concentration in the original precursor solution. Titania/gold composite films were intensely colored and showed dichromism: blue in transmitted light and red in reflected light. They showed metal-like reflection spectra and plasmon absorption. X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis confirmed the presence of metallic gold, and SEM imaging showed individual Au nanoparticles embedded in the films. X-ray diffraction detected crystalline gold in the composite films. This CVD technique can be readily extended to produce other nanocomposite films by varying the colloids and precursors used, and it offers a rapid, convenient route to nanoparticle and nanocomposite thin films. PMID:16448130

  8. Multiscale Reaction-Diffusion Algorithms: PDE-Assisted Brownian Dynamics

    KAUST Repository

    Franz, Benjamin

    2013-06-19

    Two algorithms that combine Brownian dynami cs (BD) simulations with mean-field partial differential equations (PDEs) are presented. This PDE-assisted Brownian dynamics (PBD) methodology provides exact particle tracking data in parts of the domain, whilst making use of a mean-field reaction-diffusion PDE description elsewhere. The first PBD algorithm couples BD simulations with PDEs by randomly creating new particles close to the interface, which partitions the domain, and by reincorporating particles into the continuum PDE-description when they cross the interface. The second PBD algorithm introduces an overlap region, where both descriptions exist in parallel. It is shown that the overlap region is required to accurately compute variances using PBD simulations. Advantages of both PBD approaches are discussed and illustrative numerical examples are presented. © 2013 Society for Industrial and Applied Mathematics.

  9. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  10. Generic Wavelength-routed Optical Router (GWOR) based on grating-assisted vertical couplers for multilayer optical networks

    Science.gov (United States)

    Calò, Giovanna; Petruzzelli, Vincenzo

    2016-05-01

    A Generic Wavelength-routed Optical Router (GWOR) based on grating-assisted vertical couplers is proposed to be used as 4×4 routing matrix in multilayer optical networks. The device exploits, as basic building blocks, four vertical grating-assisted couplers made of three vertically stacked waveguides. The central waveguide is patterned with a periodic Bragg grating that guarantees the wavelength routing of the signal at the Bragg wavelength. The design and the analysis of the grating-assisted vertical couplers, performed by two different numerical methods, the Bidirectional Beam Propagation Method based on the Method of Lines (MoL-BBPM) and the Finite Difference Time Domain (FDTD) method, are reported. Moreover, the GWOR matrix is analyzed, with a very limited computational effort, by suitably composing the numerically calculated transmittances of the 2×2 elementary building blocks. The proposed GWOR matrix achieves low values of the insertion loss (i.e. maximum insertion loss IL=0.2 dB) and crosstalk below -15 dB.

  11. From roaming atoms to hopping surfaces: mapping out global reaction routes in photochemistry.

    Science.gov (United States)

    Maeda, Satoshi; Taketsugu, Tetsuya; Ohno, Koichi; Morokuma, Keiji

    2015-03-18

    The photodissociation of small molecules occurs upon irradiation by ultraviolet or visible light, and it is a very important chemical process in Earth's atmosphere, in the atmospheres of other planets, and in interstellar media. Photodissociation is an important method used to thoroughly investigate the fundamental issues of chemical reactivity. Photodissociation involves molecules and reaction fragments moving over ground- and excited-state potential surfaces (PESs). Molecules can move on a single PES (adiabatic pathway) or can cross over from one PES to another (nonadiabatic pathways). For a full theoretical understanding of a photodissociation mechanism, all of the important nonadiabatic and adiabatic pathways must be determined. This is not an easy task. We have developed an efficient computational method, called the global reaction route mapping (GRRM) strategy, that allows a theoretical exploration of ground- and excited-state PESs and their crossing seams in an automatic manner. In this Perspective, we summarize our approaches and present examples of their application together with newly determined chemical insights. These include the complex photodissociation mechanism of the formaldehyde molecule, the exclusive excited-state roaming dynamics of the nitrate radical, and all product channels and conformational memory in the photodissociation of the formic acid molecule. Finally, perspectives for the theoretical design of photofunctional molecules are discussed. PMID:25705857

  12. A global reaction route mapping-based kinetic Monte Carlo algorithm

    Science.gov (United States)

    Mitchell, Izaac; Irle, Stephan; Page, Alister J.

    2016-07-01

    We propose a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. Starting from any given equilibrium state, this GRRM-KMC algorithm performs a one-step GRRM search to identify all surrounding transition states. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculated on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde and surface carbon diffusion on an iron nanoparticle. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding potential.

  13. Evaluation of Opportunistic Routing Algorithms on Opportunistic Mobile Sensor Networks with Infrastructure Assistance

    NARCIS (Netherlands)

    Le, Viet-Duc; Scholten, Hans; Havinga, Paul

    2012-01-01

    Recently the increasing number of sensors integrated in smartphones, especially the iPhone and Android phones, has motivated the development of routing algorithms for Opportunistic Mobile Sensor Networks (OppMSNs). Although there are many existing opportunistic routing algorithms, researchers still

  14. Electrochemical properties of submicron-sized LiV3O8 synthesized by a low-temperature reaction route

    International Nuclear Information System (INIS)

    Submicron-sized LiV3O8 cathode materials were synthesized using a low-temperature reaction route with the help of grinding and the following calcination. A mixture of Li(ac).2H2O(ac = acetate), NH4VO3 and excess H2C2O4.2H2O was used as starting material without any solvent. Characterization results of X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge test, and cyclic voltammogram (CV) indicated that the sample heat-treated at 350 deg. C shows the best electrochemical performance. This low-temperature reaction route is a simple but efficient synthesis route for preparing high-performance LiV3O8 cathode material

  15. Energy Considerations for Plasma-Assisted N-Fixation Reactions

    Directory of Open Access Journals (Sweden)

    Aikaterini Anastasopoulou

    2014-09-01

    Full Text Available In a time of increasing concerns about the immense energy consumption and poor environmental performance of contemporary processes in the chemical industry, there is great need to develop novel sustainable technologies that enhance energy efficiency. There is abundant chemical literature on process innovations (laboratory-scale around the plasma reactor itself, which, naturally, is the essential part to be intensified to achieve a satisfactory process. In essence, a plasma process needs attention beyond reaction engineering towards the process integration side and also with strong electrical engineering focus. In this mini-review, we have detailed our future focus on the process and energy intensification of plasma-based N-fixation. Three focal points are mainly stressed throughout the review: (I the integration of renewable energy; (II the power supply system of plasma reactors and (III process design of industrial plasma-assisted nitrogen fixation. These different enabling strategies will be set in a holistic and synergetic picture so as to improve process performance.

  16. Surfactant-assisted Nanocasting Route for Synthesis of Highly Ordered Mesoporous Graphitic Carbon and Its Application in CO2 Adsorption

    Science.gov (United States)

    Wang, Yangang; Bai, Xia; Wang, Fei; Qin, Hengfei; Yin, Chaochuang; Kang, Shifei; Li, Xi; Zuo, Yuanhui; Cui, Lifeng

    2016-05-01

    Highly ordered mesoporous graphitic carbon was synthesized from a simple surfactant-assisted nanocasting route, in which ordered mesoporous silica SBA-15 maintaining its triblock copolymer surfactant was used as a hard template and natural soybean oil (SBO) as a carbon precursor. The hydrophobic domain of the surfactant assisted SBO in infiltration into the template’s mesoporous channels. After the silica template was carbonized and removed, a higher yield of highly-ordered graphitic mesoporous carbon with rod-like morphology was obtained. Because of the improved structural ordering, the mesoporous carbon after amine modification could adsorb more CO2 compared with the amine-functionalized carbon prepared without the assistance of surfactant.

  17. strange beta: An assistance system for indoor rock climbing route setting

    Science.gov (United States)

    Phillips, C.; Becker, L.; Bradley, E.

    2012-03-01

    This paper applies the mathematics of chaos to the task of designing indoor rock-climbing routes. Chaotic variation has been used to great advantage on music and dance, but the challenges here are quite different, beginning with the representation. We present a formalized system for transcribing rock climbing problems and then describe a variation generator that is designed to support human route-setters in designing new and interesting climbing problems. This variation generator, termed strange beta, uses chaos to introduce novelty. We validated this approach with a large blinded study in a commercial climbing gym, in cooperation with experienced climbers and expert route setters. The results show that strange beta can help a human setter produce routes that are at least as good as, and in some cases better than, those produced in the traditional manner.

  18. Microwave-Assisted Organic Synthesis in the Organic Teaching Lab: A Simple, Greener Wittig Reaction

    Science.gov (United States)

    Martin, Eric; Kellen-Yuen, Cynthia

    2007-01-01

    A greener, microwave-assisted Wittig reaction has been developed for the second-semester organic teaching laboratory. Utilizing this microwave technique, a variety of styrene derivatives have been successfully synthesized from aromatic aldehydes in good yields (41-68%). The reaction not only occurs under neat reaction conditions, but also employs…

  19. A route to hydroxylfluorenes: TsOH-mediated condensation reactions of 1,3-diketones with propargylic alcohols

    KAUST Repository

    Yao, Liangfeng

    2012-01-01

    An efficient method of preparing hydroxylfluorenes by TsOH-mediated tandem alkylation/rearrangements of propargylic alcohols with 1,3-diketones is described. These reactions are accomplished in moderate to good yields under mild conditions to offer a straightforward and convenient one step synthetic route to hydroxylfluorene derivatives through a plausible mechanism involving a sequence of dehydration, addition, rearrangement and aromatization. This journal is © The Royal Society of Chemistry 2012.

  20. Continuous Synthesis and Thermal Elimination of Sulfinyl-Route Poly(p-Phenylene Vinylene) in Consecutive Flow Reactions

    OpenAIRE

    Zaquen, Neomy; Baeten, Evelien; Vandenbergh, Joke; Lutsen, Laurence; Vanderzande, Dirk J. M.; Junkers, Thomas

    2015-01-01

    Continuous synthesis of multistep polymerizations at microscale is made available by coupling two microstructured chip reactors in a single reactor setup. Conjugated [2-methoxy-5-(3,7-dimethyloctyloxy)]-1,4-phenylenevinylene (MDMO-PPV) is synthesized via the radical sulfinyl precursor route. Reactions are carried out in separate reactors and optimization of the elimination of polymer can be effectively performed in a defined temperature range, allowing for full polymer conversion within minut...

  1. Relaxor behaviour in BaBi4Ti4O15 ceramics fabricated using the powders obtained by mechanochemically assisted synthesis route

    Indian Academy of Sciences (India)

    Sunil Kumar; K B R Varma

    2014-10-01

    Mechanochemically activated reactants were found to facilitate the synthesis of fine powders comprising 200–400 nm range crystallites of BaBi4Ti4O15 at a significantly lower temperature (700 °C) than that of solid-state reaction route. Reactants (CaCO3, Bi2O3 and TiO2) in stoichiometric ratio were ball milled for 48 h to obtain homogeneous mixture. The evolution of the BaBi4Ti4O15 phase was systematically followed using X-ray powder diffraction (XRD) technique. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to probe its structural and microstructural details. The electron diffraction studies established the presence of correlated octahedral rotations and associated long-range polar ordering. High-resolution TEM imaging nevertheless revealed structural inhomogeneities leading to intergrowth defects. Dense BaBi4Ti4O15 ceramics with an average grain size of 0.9 m were fabricated using mechanochemically assisted synthesized powders at relatively low temperature (1000 °C). The effect of grain size on the dielectric and relaxor behaviour of BaBi4Ti4O15 ceramics was investigated. Fine-grained ceramics (average grain size ∼ 0.9 m) showed higher diffusion in phase transition, lower temperature of phase transition, lower Vogel–Fulcher freezing temperature and higher activation energy for the polarization reversal than those for coarse-grained ceramics (average grain size ∼ 7 m) fabricated via the conventional solid-state reaction route.

  2. Inspired superhydrophobic surfaces by a double-metal-assisted chemical etching route

    International Nuclear Information System (INIS)

    Graphical abstract: A double-metal-assisted chemical etching method is employed to fabricate superhydrophobic surfaces, showing a good superhydrophobicity with the contact angle of about 170°, and the sliding angle of about 0°. Meanwhile, the potential formation mechanism about it is also presented. Highlights: ► A double-metal-assisted chemical etching method is employed to fabricate superhydrophobic surfaces. ► The obtained surfaces show good superhydrophobicity with a high contact angle and low sliding angle. ► The color of the etched substrate dark brown or black and it is so-called black silicon. -- Abstract: Silicon substrates treated by metal-assisted chemical etching have been studied for many years since they could be employed in a variety of electronic and optical devices such as integrated circuits, photovoltaics, sensors and detectors. However, to the best of our knowledge, the chemical etching treatment on the same silicon substrate with the assistance of two or more kinds of metals has not been reported. In this paper, we mainly focus on the etching time and finally obtain a series of superhydrophobic silicon surfaces with novel etching structures through two successive etching processes of Cu-assisted and Ag-assisted chemical etching. It is shown that large-scale homogeneous but locally irregular wire-like structures are obtained, and the superhydrophobic surfaces with low hysteresis are prepared after the modifications with low surface energy materials. It is worth noting that the final silicon substrates not only possess high static contact angle and low hysteresis angle, but also show a black color, indicating that the superhydrophobic silicon substrate has an extremely low reflectance in a certain range of wavelengths. In our future work, we will go a step further to discuss the effect of temperature, the size of Cu nanoparticles and solution concentration on the final topography and superhydrophobicity.

  3. Investigation of primary crystallite sizes in nanocrystalline ZnS powders: comparison of microwave assisted with conventional synthesis routes.

    Science.gov (United States)

    Rath, Thomas; Kunert, Birgit; Resel, Roland; Fritz-Popovski, Gerhard; Saf, Robert; Trimmel, Gregor

    2008-04-21

    ZnS powders with primary crystallite sizes of only a few nanometers were prepared by three different synthesis routes at temperatures below 130 degrees C. The reaction of zinc acetate dihydrate with thioacetamide (TAA) in the presence of pyridine and triphenylphosphite (TPP) was carried out using either conventional heating or microwave heating. The obtained powders exhibit sphalerite structure as determined by X-ray diffraction (XRD). The primary crystallites have diameters between 1 and 7 nm obtained by XRD. Small angle X-ray scattering (SAXS) measurements were analyzed by the model-free inverse Fourier-transformation approach, as well as by a hard sphere-model from which particle size and polydispersity were extracted. The particle sizes by SAXS are in good agreement with the primary crystallite sizes obtained by XRD. It has been found that an increasing amount of sulfur and/or using microwave heating increases crystallite sizes. The presence of TPP decreases the particle sizes but no significant influence on the TPP concentration was observed. In the alternative third preparation route, hexamethyldisilathiane (HMDST) was used as precipitation reagent at ambient temperature, which leads to the smallest crystallite sizes of only 1 nm together with low polydispersities. Scanning electron microscopy, dynamic light scattering and UV-vis spectroscopy showed that all three synthesis routes lead to ZnS powders with aggregate sizes between 650 and 1200 nm. Both of the TAA-precipitation routes lead to spherical agglomerates which consist of spherical substructures, whereas the HMDST agglomerates are assembled from elongated objects. PMID:18351732

  4. Innovative biofilm inhibition and anti-microbial behavior of molybdenum sulfide nanostructures generated by microwave-assisted solvothermal route

    Science.gov (United States)

    Qureshi, Nilam; Patil, Rajendra; Shinde, Manish; Umarji, Govind; Causin, Valerio; Gade, Wasudev; Mulik, Uttam; Bhalerao, Anand; Amalnerkar, Dinesh P.

    2015-03-01

    The incessant use of antibiotics against infectious diseases has translated into a vicious circle of developing new antibiotic drug and its resistant strains in short period of time due to inherent nature of micro-organisms to alter their genes. Many researchers have been trying to formulate inorganic nanoparticles-based antiseptics that may be linked to broad-spectrum activity and far lower propensity to induce microbial resistance than antibiotics. The way-out approaches in this direction are nanomaterials based (1) bactericidal and (2) bacteriostatic activities. We, herein, present hitherto unreported observations on microbial abatement using non-cytotoxic molybdenum disulfide nanostructures (MSNs) which are synthesized using microwave assisted solvothermal route. Inhibition of biofilm formation using MSNs is a unique feature of our study. Furthermore, this study evinces antimicrobial mechanism of MSNs by reactive oxygen species (ROS) dependent generation of superoxide anion radical via disruption of cellular functions.

  5. ZrTiO4 nanowire growth using membrane-assisted Pechini route

    Directory of Open Access Journals (Sweden)

    P. R. de Lucena

    2014-11-01

    Full Text Available The high surface-to-volume ratio of nanowires makes them natural competitors as new device components. In this regard, a current major challenge is to produce quasi-one-dimensional nanostructures composed of well established oxide-based materials. This article reports the synthesis of ZrTiO4 nanowires on a silicon (100 wafer in a single-step deposition/thermal treatment. The template-directed membrane synthesis strategy was associated with the Pechini route and spin-coating deposition technique. ZrTiO4 nanowires were obtained at 700 ˚C with diameters in the range of 80-100 nm. FEG- SEM images were obtained to investigate ZrTiO4 nanowire formation on the silicon surface and energy dispersive x-ray detection (EDS and x-ray diffraction (XRD analyses were performed to confirm the oxide composition and structure.

  6. Hydrogen-Assisted IC Engine Combustion as a Route to Hydrogen Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Andre Boehman; Daniel Haworth

    2008-09-30

    The 'Freedom Car' Initiative announced by the Bush Administration has placed a significant emphasis on development of a hydrogen economy in the United States. While the hydrogen-fueled fuel-cell vehicle that is the focus of the 'Freedom Car' program would rely on electrochemical energy conversion, and despite the large amount of resources being devoted to its objectives, near-term implementation of hydrogen in the transportation sector is not likely to arise from fuel cell cars. Instead, fuel blending and ''hydrogen-assisted'' combustion are more realizable pathways for wide-scale hydrogen utilization within the next ten years. Thus, a large potential avenue for utilization of hydrogen in transportation applications is through blending with natural gas, since there is an existing market for natural-gas vehicles of various classes, and since hydrogen can provide a means of achieving even stricter emissions standards. Another potential avenue is through use of hydrogen to 'assist' diesel combustion to permit alternate combustion strategies that can achieve lower emissions and higher efficiency. This project focused on developing the underlying fundamental information to support technologies that will facilitate the introduction of coal-derived hydrogen into the market. Two paths were envisioned for hydrogen utilization in transportation applications. One is for hydrogen to be mixed with other fuels, specifically natural gas, to enhance performance in existing natural gas-fueled vehicles (e.g., transit buses) and provide a practical and marketable avenue to begin using hydrogen in the field. A second is to use hydrogen to enable alternative combustion modes in existing diesel engines, such as homogeneous charge compression ignition, to permit enhanced efficiency and reduced emissions. Thus, this project on hydrogen-assisted combustion encompassed two major objectives: (1) Optimization of hydrogen-natural gas mixture

  7. Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

    Directory of Open Access Journals (Sweden)

    Ishmael B. Masesane

    2012-12-01

    Full Text Available The reported methodologies for the synthesis of chromane derivatives through the reaction of salicylaldehyde and enolates are discussed. The enolates and their equivalents involved in the reactions discussed in this article were derived from ketones, nitroalkanes, malononitrile and α,β-unsaturated compounds.

  8. Microchips in Organics Chemistry: NMR Microcoils for Reaction Monitoring and Computational Chemistry for Microwave-Assisted Reactions

    OpenAIRE

    Rodríguez García, Antonio Manuel

    2014-01-01

    Durante los últimos cuatro años, he estado trabajando en el desarrollo de mi tesis doctoral titulada Microchip in Organic Chemistry: NMR Microcoils for Reaction Monitorization and Computational Chemistry for Microwave-Assisted reactions, realizada bajo la supervisión del Dr. Antonio de la Hoz Ayuso y la Dra. Victoria Gómez Almagro en el área de Química Orgánica en esta facultad. La novedad principal de esta tesis se recoge en un enfoque de resolución de los problemas mediante una perspectiva...

  9. Particle size and shape modification of hydroxyapatite nanostructures synthesized via a complexing agent-assisted route

    Energy Technology Data Exchange (ETDEWEB)

    Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box. 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of)

    2014-07-01

    In this work, hydroxyapatite (HAP), Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, nanostructures including nanorods, nanobundles and nanoparticles have been prepared via a simple precipitation method. In the present method, Ca(NO{sub 3}){sub 2}·4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4} were used as calcium and phosphorus precursors, respectively. Besides, the Schiff bases derived from 2-hydroxyacetophenone and different diamines were used as complexing agents for the in situ formation of Ca{sup 2+} complexes. The formation mechanism of 0-D and 1-D nanostructures of HAP was also considered. When the complexing agents could coordinate to the Ca{sup 2+} ions through N and O atoms to form the [CaN{sub 2}O{sub 2}]{sup 2+} complexes, HAP nanoparticles were generated. On the other hand, nanorods and nanobundles of HAP were obtained by forming the [CaN{sub 2}]{sup 2+} as well as [CaO{sub 2}]{sup 2+} complexes in the reaction solution. This work is the first successful synthesis of pure HAP nanostructures in the presence of Schiff bases instead of using the common surfactants. - Highlights: • HAP nanostructures have been prepared by a simple precipitation method. • To control shape and particle size of HAP, different Schiff bases were employed. • 0-D and 1-D HAP nanostructures have been formed by this method.

  10. Efficient and 'green' microwave-assisted synthesis of haloalkylphosphonates via the Michaelis-Arbuzov reaction

    Czech Academy of Sciences Publication Activity Database

    Jansa, Petr; Holý, Antonín; Dračínský, Martin; Baszczyňski, Ondřej; Česnek, Michal; Janeba, Zlatko

    2011-01-01

    Roč. 13, č. 4 (2011), s. 882-888. ISSN 1463-9262 R&D Projects: GA AV ČR KJB400550903; GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : microwave-assisted synthesis * haloalkylphosphonates * Michaelis-Arbuzov reaction Subject RIV: CC - Organic Chemistry Impact factor: 6.320, year: 2011

  11. Magnetic field assisted Fenton reactions for the enhanced degradation of methyl blue

    Institute of Scientific and Technical Information of China (English)

    Xiao Long Hao; Lu Yi Zou; Guang Sheng Zhang; Yi Bo Zhang

    2009-01-01

    Magnetic field was tentatively introduced into Fenton reactions system for the degradation and discoloration of methyl blue as the represent of organic chemical dye, which was a bio-refractory organic pollutant in industry wastewater. It was found that under optimal Fenton reaction conditions, with the assistant of magnetic field in Fenton reactions, the degradation rate of methyl blue, the decomposition rate of H2O2 and the conversion rate of Fe2+ were accelerated, the extent of them would be improved by the increase of magnetic field intensity. Meanwhile, the mineralization of methyl blue (CODcr) was improved by over 10% with magnetic fiold.

  12. Dipolar Cycloaddition Reactions with Quinazolinones: A New Route for the Synthesis of Several Annelated Pyrrolo- and Pyridazinoquinazoline Derivatives

    OpenAIRE

    Gaber, Hatem M.; Sami S. Ghabrial

    2003-01-01

    The novel 2-aryl-3a,4,12,12a-tetrahydropyrrolo[3',4':4,3]-pyridazino[6,1-b]-quinazoline-1,3,6-triones (6a–d), 2-aryl-10-oxopyridazino[6,1-b]-quinazoline-3-thio-carboxamides (10a–d) and 2-aryl-3-nitro-1,2,3,4-tetrahydro-pyridazino[6,1-b]quinazolin-10-ones (12a–d) were synthesized via a new, facile one step route involving the reactions of the zwitterion 4, formed in situ, with a variety of N-arylmaleimides 5, 3-aryl-2-cyano-thioacrylamides 8 and É-nitrostyrenes 11. Dehydrogena...

  13. From Roaming Atoms to Hopping Surfaces: Mapping Out Global Reaction Routes in Photochemistry

    OpenAIRE

    MAEDA, SATOSHI; Taketsugu, Tetsuya; OHNO, Koichi; Morokuma, Keiji

    2015-01-01

    The photodissociation of small molecules occurs upon irradiation by ultraviolet visible light, and it is a very important Chemical process in Earth's atmosphere, in the atmospheres of other planets, and in interstellar media. Photodissociation is an important method used to thoroughly investigate the fundamental issues of chemical,reactivity. Photodissociation involves Molecules and reaction fragments moving over ground and excited-state potential surfaces (PESs). Molecules can move on a sing...

  14. From roaming atoms to hopping surfaces: mapping out global reaction routes in photochemistry.

    OpenAIRE

    MAEDA, SATOSHI; Taketsugu, Tetsuya; OHNO, Koichi; Morokuma, Keiji

    2015-01-01

    The photodissociation of small molecules occurs upon irradiation by ultraviolet or visible light, and it is a very important chemical process in Earth's atmosphere, in the atmospheres of other planets, and in interstellar media. Photodissociation is an important method used to thoroughly investigate the fundamental issues of chemical reactivity. Photodissociation involves molecules and reaction fragments moving over ground- and excited-state potential surfaces (PESs). Molecules can move on a ...

  15. Computer aided design, analysis and experimental investigation of membrane assisted batch reaction-separation systems

    DEFF Research Database (Denmark)

    Mitkowski, Piotr Tomasz; Buchaly, Carsten; Kreis, Peter; Jonsson, Gunnar Eigil; Gorak, Andrzej; Gani, Rafiqul

    2009-01-01

    Membrane assisted batch reaction operation offers an interesting option for equilibrium limited reaction systems in chemical and biochemical manufacturing by selective removal of one of the products and thereby increasing the product yield. The design of such hybrid systems need to take into...... account the performance of each constituent element and the optimisation of the design must take into consideration their interdependency. In this paper use of a membrane, to assist in the synthesis of propyl-propionate is investigated through the use of a hybrid process design framework, which consists...... and separation functionalities and to design/analyse the hybrid scheme. The generated hybrid scheme has been validated through experiments involving an esterification reaction....

  16. The production of SiC-matrix composites via the reaction-bonding route

    Science.gov (United States)

    Higgins, I.; Whitehead, A. J.

    The fabrication of reaction-bonded silicon carbide components by infiltrating a silicon carbide:carbon powder preform with molten silicon is a well established commercial technique. In the present work this process has been developed to yield a family of SiC-matrix, particulate reinforced composites by varying compositions of the preform and/or the infiltrating liquid. Examples of both boron- and titanium-containing composites are given and the microstructural developments during firing are discussed using available thermodynamic data. The nature of crack propagation through the materials and the role of the secondary particulate phases are described.

  17. Study on structural and magnetic properties of nanosized M-type Ba-hexaferrites synthesized by urea assisted citrate precursor route

    International Nuclear Information System (INIS)

    Graphical abstract: The correlation between distribution of cations over five crystallographic positions and magnetic properties of Ba-hexaferrites in the coupled substitution of magnetic Co2+ and non-magnetic Zr4+ for Fe3+ is investigated by urea assisted citrate precursor route. BET surface area of sample is 34.86 m2/g. Dopant ions largely prefer 4f1 and 2a sites up to 0.8 level while substitution at 12k, 4f1 and 2a sites is indicated at higher concentrations. The coercive force is steeply reduced from 5017 to 589 Oe with increasing Co–Zr contents but net magnetization is nearly constant (MS = 50.38–63.54 emu/g). - Highlights: • Nanosized M-type hexaferrites have been synthesized by urea assisted citrate precursor method. • Mössbauer study indicates that distribution of Co–Zr on sublattices is monitored by reaction stoichiometry. • Large variations in MS and HC values at same doping level prove their substantially different nature. • Studies shows that magnetic properties can be modulated by varying the preparatory conditions. • BET study indicates that these types of compounds may be used for the catalytic activity. - Abstract: In our efforts to investigate the correlation between the distribution of cations over five crystallographic positions and magnetic properties of Ba-hexaferrites in the coupled substitution of magnetic Co2+ and non-magnetic Zr4+ for Fe3+ by urea assisted citrate precursor route. During present research, the polycrystalline samples of series of BaCoxZrxFe(12−2x)O19 (x = 0.0–1.0) ferrites have been prepared with aim to study the magnetic properties including coercivity, remanance and magnetic saturation at room temperature. Urea and citrate were used as fuels in the presence of nitric acid. Single phase M-type hexagonal ferrites are formed at 800 °C which is confirmed by Powder X-ray diffraction. The average size of hexagonal platelets is 39 nm. BET surface area of sample is 34.86 m2/g. Mössbauer studies suggest that

  18. Study on structural and magnetic properties of nanosized M-type Ba-hexaferrites synthesized by urea assisted citrate precursor route

    Energy Technology Data Exchange (ETDEWEB)

    Mudsainiyan, R.K., E-mail: mudsainiyanrk@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Jassal, A.K. [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Gupta, Munish [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Department of Chemistry, DAV College, Amritsar, Punjab 143001 (India); Chawla, S.K. [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India)

    2015-10-05

    Graphical abstract: The correlation between distribution of cations over five crystallographic positions and magnetic properties of Ba-hexaferrites in the coupled substitution of magnetic Co{sup 2+} and non-magnetic Zr{sup 4+} for Fe{sup 3+} is investigated by urea assisted citrate precursor route. BET surface area of sample is 34.86 m{sup 2}/g. Dopant ions largely prefer 4f{sub 1} and 2a sites up to 0.8 level while substitution at 12k, 4f{sub 1} and 2a sites is indicated at higher concentrations. The coercive force is steeply reduced from 5017 to 589 Oe with increasing Co–Zr contents but net magnetization is nearly constant (M{sub S} = 50.38–63.54 emu/g). - Highlights: • Nanosized M-type hexaferrites have been synthesized by urea assisted citrate precursor method. • Mössbauer study indicates that distribution of Co–Zr on sublattices is monitored by reaction stoichiometry. • Large variations in M{sub S} and H{sub C} values at same doping level prove their substantially different nature. • Studies shows that magnetic properties can be modulated by varying the preparatory conditions. • BET study indicates that these types of compounds may be used for the catalytic activity. - Abstract: In our efforts to investigate the correlation between the distribution of cations over five crystallographic positions and magnetic properties of Ba-hexaferrites in the coupled substitution of magnetic Co{sup 2+} and non-magnetic Zr{sup 4+} for Fe{sup 3+} by urea assisted citrate precursor route. During present research, the polycrystalline samples of series of BaCo{sub x}Zr{sub x}Fe{sub (12−2x)}O{sub 19} (x = 0.0–1.0) ferrites have been prepared with aim to study the magnetic properties including coercivity, remanance and magnetic saturation at room temperature. Urea and citrate were used as fuels in the presence of nitric acid. Single phase M-type hexagonal ferrites are formed at 800 °C which is confirmed by Powder X-ray diffraction. The average size of

  19. Collisions of Rare Earth Nuclei - a New Reaction Route for Synthesis of Super Heavy Nuclei

    CERN Document Server

    Choudhury, R K

    2012-01-01

    Theories have predicted an island of stability in the super heavy mass region with half lives ranging from a few seconds to a few thousands of years. Extensive efforts are being made experimentally to reach these nuclei in the region of Z = 110 and above with suitable combinations of proton and neutron numbers. However, the cross sections for production of these nuclei are seen to be in the range of a few pico barns or less, and pose great experimental challenges. We show in the present note that great advantages can be obtained by carrying out heavy ion reactions with suitable combinations of projectile and target nuclei in the rare earth region, that will lead to compound systems with very small excitation energy, and with better neutron/proton ratio for larger stability.

  20. Effect of reaction systems and surfactant additives on the morphology evolution of hydroxyapatite nanorods obtained via a hydrothermal route

    International Nuclear Information System (INIS)

    Well-dispersed hydroxyapatite (HA) nanorods with different morphologies were synthesized by a hydrothermal method in oleic acid, ethanol and water reaction system, and the surfactant assisted modifications effect was also comparatively studied. The structure and morphology of samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM), respectively. The effect of reaction systems and surfactant additives on the morphology evolution of HA nanorods were discussed in detail. The results showed that the controlled experimental conditions in the systems, such as the content ratio of oleic acid/ethanol, pH value and the content ratio of Ca/P source had an significant effect on the morphology evolution of as-prepared HA nanorods. Further, the selected surfactant additives, such as cetyltriethylammnonium bromide (CTAB), sodium dodecyl sulfate (K12) also play an important role in the formation of the uniform morphology of HA nanorods. Some possible formation mechanisms of the HA nanorods in the present reaction systems is proposed.

  1. Synthesis of high intrinsic loss power aqueous ferrofluids of iron oxide nanoparticles by citric acid-assisted hydrothermal-reduction route

    Energy Technology Data Exchange (ETDEWEB)

    Behdadfar, Behshid, E-mail: bbehdadfar@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, Ahmad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi-Aliabadi, Hojjat [School of Pharmacy, Isfahan Pharmaceutical Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid (Spain); Mozaffari, Morteza [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-03-15

    Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids were stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm{sup 2}/kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: Black-Right-Pointing-Pointer Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. Black-Right-Pointing-Pointer Citric acid acted as reducing agent and surfactant in the route. Black-Right-Pointing-Pointer This is a facile, low energy and environmental friendly route. Black-Right-Pointing-Pointer The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. Black-Right-Pointing-Pointer The calculated intrinsic loss power of the synthesized ferrofluids was very high.

  2. Understanding recovery in children following traffic-related injuries: Exploring acute traumatic stress reactions, child coping, and coping assistance

    OpenAIRE

    Marsac, Meghan L; Donlon, Katharine A.; Hildenbrand, Aimee K.; Winston, Flaura K.; Kassam-Adams, Nancy

    2013-01-01

    Millions of children incur potentially traumatic physical injuries every year. Most children recover well from their injury but many go on to develop persistent traumatic stress reactions. This study aimed to describe children’s coping and coping assistance (i.e., the ways in which parents and peers help children cope) strategies and to explore the association between coping and acute stress reactions following an injury. Children (N = 243) rated their acute traumatic stress reactions within ...

  3. Comparative study of potassium hexatitanate (K2Ti6O13) whiskers prepared by sol-gel and solid state reaction routes

    Science.gov (United States)

    Siddiqui, Mohd Asim; Chandel, Vishal Singh; Azam, Ameer

    2012-07-01

    Polycrystalline phases of the potassium hexatitanate (K2Ti6O13) were synthesized by conventional solid state reaction and sol-gel methods with a view to compare structural, electrical, optical and photocatalytic properties. Single phase K2Ti6O13 prepared by sol-gel method (PSG) revealed higher value of dielectric constant than same obtained by the solid state reaction method (PSS), attributed to smaller particle size in sol-gel method. Band gap (3.48 eV) of K2Ti6O13 prepared by sol-gel method was found higher than (3.06 eV), obtained in solid state reaction method. Additionally, K2Ti6O13 was tested as photocatalyst on the degradation of methyl orange (MO) under UV light and found better activity for sample PSG. Morphological characteristic exhibited formation of nanorods in sol-gel route and formation of microrods in solid state reaction method.

  4. Designing driver assistance systems with crossmodal signals: multisensory integration rules for saccadic reaction times apply.

    Directory of Open Access Journals (Sweden)

    Rike Steenken

    Full Text Available Modern driver assistance systems make increasing use of auditory and tactile signals in order to reduce the driver's visual information load. This entails potential crossmodal interaction effects that need to be taken into account in designing an optimal system. Here we show that saccadic reaction times to visual targets (cockpit or outside mirror, presented in a driving simulator environment and accompanied by auditory or tactile accessories, follow some well-known spatiotemporal rules of multisensory integration, usually found under confined laboratory conditions. Auditory nontargets speed up reaction time by about 80 ms. The effect tends to be maximal when the nontarget is presented 50 ms before the target and when target and nontarget are spatially coincident. The effect of a tactile nontarget (vibrating steering wheel was less pronounced and not spatially specific. It is shown that the average reaction times are well-described by the stochastic "time window of integration" model for multisensory integration developed by the authors. This two-stage model postulates that crossmodal interaction occurs only if the peripheral processes from the different sensory modalities terminate within a fixed temporal interval, and that the amount of crossmodal interaction manifests itself in an increase or decrease of second stage processing time. A qualitative test is consistent with the model prediction that the probability of interaction, but not the amount of crossmodal interaction, depends on target-nontarget onset asynchrony. A quantitative model fit yields estimates of individual participants' parameters, including the size of the time window. Some consequences for the design of driver assistance systems are discussed.

  5. Strange Beta: An Assistance System for Indoor Rock Climbing Route Setting Using Chaotic Variations and Machine Learning

    CERN Document Server

    Phillips, Caleb; Bradley, Elizabeth

    2011-01-01

    This paper applies machine learning and the mathematics of chaos to the task of designing indoor rock-climbing routes. Chaotic variation has been used to great advantage on music and dance, but the challenges here are quite different, beginning with the representation. We present a formalized system for transcribing rock climbing problems, then describe a variation generator that is designed to support human route-setters in designing new and interesting climbing problems. This variation generator, termed Strange Beta, combines chaos and machine learning, using the former to introduce novelty and the latter to smooth transitions in a manner that is consistent with the style of the climbs This entails parsing the domain-specific natural language that rock climbers use to describe routes and movement and then learning the patterns in the results. We validated this approach with a pilot study in a small university rock climbing gym, followed by a large blinded study in a commercial climbing gym, in cooperation w...

  6. Rapid Covalent Modification of Silicon Oxide Surfaces through Microwave-Assisted Reactions with Alcohols.

    Science.gov (United States)

    Lee, Austin W H; Gates, Byron D

    2016-07-26

    We demonstrate the method of a rapid covalent modification of silicon oxide surfaces with alcohol-containing compounds with assistance by microwave reactions. Alcohol-containing compounds are prevalent reagents in the laboratory, which are also relatively easy to handle because of their stability against exposure to atmospheric moisture. The condensation of these alcohols with the surfaces of silicon oxides is often hindered by slow reaction kinetics. Microwave radiation effectively accelerates this condensation reaction by heating the substrates and/or solvents. A variety of substrates were modified in this demonstration, such as silicon oxide films of various thicknesses, glass substrates such as microscope slides (soda lime), and quartz. The monolayers prepared through this strategy demonstrated the successful formation of covalent surface modifications of silicon oxides with water contact angles of up to 110° and typical hysteresis values of 2° or less. An evaluation of the hydrolytic stability of these monolayers demonstrated their excellent stability under acidic conditions. The techniques introduced in this article were successfully applied to tune the surface chemistry of silicon oxides to achieve hydrophobic, oleophobic, and/or charged surfaces. PMID:27396288

  7. CRISPR/Cas9-Assisted Transformation-Efficient Reaction (CRATER) for Near-Perfect Selective Transformation

    Science.gov (United States)

    Rothschild, Lynn J.; Greenberg, Daniel T.; Takahashi, Jack R.; Thompson, Kirsten A.; Maheshwari, Akshay J.; Kent, Ryan E.; McCutcheon, Griffin; Shih, Joseph D.; Calvet, Charles; Devlin, Tyler D.; Ju, Tina; Kunin, Daniel; Lieberman, Erica; Nguyen, Thai; Tran, Forrest; Xiang, Daniel; Fujishima, Kosuke

    2015-01-01

    The CRISPR (Clustered, Regularly Interspaced, Short Palindromic Repeats)/Cas9 system has revolutionized genome editing by providing unprecedented DNA-targeting specificity. Here we demonstrate that this system can be also applied in vitro to fundamental cloning steps to facilitate efficient plasmid selection for transformation and selective gene insertion into plasmid vectors by cleaving unwanted plasmid byproducts with a single-guide RNA (sgRNA)-Cas9 nuclease complex. Using fluorescent and chromogenic proteins as reporters, we demonstrate that CRISPR/Cas9 cleavage excludes multiple plasmids as well as unwanted ligation byproducts resulting in an unprecedented increase in the transformation success rate from approximately 20% to nearly 100%. Thus, this CRISPR/Cas9-Assisted Transformation-Efficient Reaction (CRATER) protocol is a novel, inexpensive, and convenient application to conventional molecular cloning to achieve near-perfect selective transformation.

  8. A New Route to Azafluoranthene Natural Products via Direct Arylation

    OpenAIRE

    Ponnala, Shashikanth; Harding, Wayne W.

    2013-01-01

    Microwave-assisted direct arylation was successfully employed in the synthesis of azafluoranthene alkaloids for the first time. Direct arylation reactions on a diverse set of phenyltetrahydroisoquinolines produces the indeno[1,2,3-ij]isoquinoline nucleus en route to a high yielding azafluoranthene synthesis.

  9. Charge Exchange Reaction in Dopant-Assisted Atmospheric Pressure Chemical Ionization and Atmospheric Pressure Photoionization

    Science.gov (United States)

    Vaikkinen, Anu; Kauppila, Tiina J.; Kostiainen, Risto

    2016-04-01

    The efficiencies of charge exchange reaction in dopant-assisted atmospheric pressure chemical ionization (DA-APCI) and dopant-assisted atmospheric pressure photoionization (DA-APPI) mass spectrometry (MS) were compared by flow injection analysis. Fourteen individual compounds and a commercial mixture of 16 polycyclic aromatic hydrocarbons were chosen as model analytes to cover a wide range of polarities, gas-phase ionization energies, and proton affinities. Chlorobenzene was used as the dopant, and methanol/water (80/20) as the solvent. In both techniques, analytes formed the same ions (radical cations, protonated molecules, and/or fragments). However, in DA-APCI, the relative efficiency of charge exchange versus proton transfer was lower than in DA-APPI. This is suggested to be because in DA-APCI both dopant and solvent clusters can be ionized, and the formed reagent ions can react with the analytes via competing charge exchange and proton transfer reactions. In DA-APPI, on the other hand, the main reagents are dopant-derived radical cations, which favor ionization of analytes via charge exchange. The efficiency of charge exchange in both DA-APPI and DA-APCI was shown to depend heavily on the solvent flow rate, with best efficiency seen at lowest flow rates studied (0.05 and 0.1 mL/min). Both DA-APCI and DA-APPI showed the radical cation of chlorobenzene at 0.05-0.1 mL/min flow rate, but at increasing flow rate, the abundance of chlorobenzene M+. decreased and reagent ion populations deriving from different gas-phase chemistry were recorded. The formation of these reagent ions explains the decreasing ionization efficiency and the differences in charge exchange between the techniques.

  10. Efficient processing of reaction-sintered silicon carbide by anodically oxidation-assisted polishing

    Science.gov (United States)

    Tu, Qunzhang; Shen, Xinmin; Zhou, Jianzhao; He, Xiaohui; Yamamura, Kazuya

    2015-10-01

    Reaction-sintered silicon carbide (RS-SiC) is a promising optical material for the space telescope systems. Anodically oxidation-assisted polishing is a method to machine RS-SiC. The electrolyte used in this study is a mixture of hydrogen peroxide (H2O2) and hydrochloric acid (HCl), and the oxidation potential has two modes: constant potential and high-frequency-square-wave potential. Oxide morphologies are compared by scanning electron microscope/energy dispersive x-ray spectroscopy and scanning white-light interferometer. The results indicate that anodic oxidation under constant potential can not only obtain a relatively smooth surface but also be propitious to obtain high material removal rate. The oxidation depth in anodic oxidation under constant potential is calculated by comparing surface morphologies before and after hydrofluoric acid etching. The theoretical oxidation rate is 5.3 nm/s based on the linear Deal-Grove model. Polishing of the oxidized RS-SiC is conducted to validate the machinability of the oxide layer. The obtained surface roughness root-mean-square is around 4.5 nm. Thus, anodically oxidation-assisted polishing can be considered as an efficient method, which can fill the performance gap between the rough figuring and fine finishing of RS-SiC. It can improve the machining quality of RS-SiC parts and promote the application of RS-SiC products.

  11. The Production of Biodiesel and Bio-kerosene from Coconut Oil Using Microwave Assisted Reaction

    Science.gov (United States)

    SAIFUDDIN, N.; SITI FAZLILI, A.; KUMARAN, P.; PEI-JUA, N.; PRIATHASHINI, P.

    2016-03-01

    Biofuels including biodiesel, an alternative fuel, is renewable, environmentally friendly, non-toxic and low emissions. The raw material used in this work was coconut oil, which contained saturated fatty acids about 90% with high percentage of medium chain (C8-C12), especially lauric acid and myristic acid. The purpose of this research was to study the effect of power and NaOH catalyst in transesterification assisted by microwave for production of biofuels (biodiesel and bio-kerosene) derived from coconut oil. The reaction was performed with oil and methanol using mole ratio of 1:6, catalyst concentration of 0.6% with microwave power at 100W, 180W, 300W, 450W, 600W, and 850W. The reaction time was set at of 3, 5, 7, 10 and 15 min. The results showed that microwave could accelerate the transesterification process to produce biodiesel and bio-kerosene using NaOH catalyst. The highest yield of biodiesel was 97.17 %, or 99.05 % conversion at 5 min and 100W microwave power. Meanwhile, the bio-kerosene obtained was 65% after distillation.

  12. Reaction efficiency of organic alkalis with various classes of lipids during thermally assisted hydrolysis and methylation.

    Science.gov (United States)

    Ishida, Yasuyuki; Katagiri, Mizuho; Ohtani, Hajime

    2009-04-10

    Reaction efficiencies of two organic alkalis, tetramethylammonium hydroxide (TMAH) and trimethylsulfonium hydroxide (TMSH), with lipids during thermally assisted hydrolysis and methylation (THM) were examined focusing on (1) the types of lipids and (2) degree of unsaturation of fatty acid moieties. Different types of lipids such as triglycerides, phospholipids, free fatty acids and cholesteryl esters containing saturated, monounsaturated or polyunsaturated fatty acid (PUFA) residues were subjected to THM-gas chromatography (GC) in the presence of TMAH or TMSH. The obtained results revealed that the THM reaction using TMAH allowed almost quantitative methylation of saturated and monounsaturated fatty acid components independently of the classes of lipids. However, strong alkalinity of TMAH brought about isomerization and/or degradation of PUFA components. In contrast, the use of TMSH was effective to highly sensitive detection of PUFA as well as saturated and monounsaturated fatty acid components contained in triglycerides, phospholipids (phosphatidylcholines) and free fatty acids. On the other hand, TMSH was proved to react hardly with any kind of fatty acid residues in cholesteryl esters due to their steric hindrance. PMID:19223033

  13. Nuclear model analysis of excitation functions of proton induced reactions on 86Sr, 88Sr and natZr: Evaluation of production routes of 86Y

    International Nuclear Information System (INIS)

    The proton induced nuclear reactions on 86Sr, 88Sr and natZr were investigated for the production of 86Y. The literature data were compared with the results of nuclear model calculations using the codes ALICE-IPPE, TALYS 1.6 and EMPIRE 3.2. The thick target yields of 86Y were calculated from the recommended excitation functions. Analysis of radioyttrium impurities was also performed. A comparison of the various production routes showed that for medical applications of 86Y, the reaction 86Sr(p,n)86Y is the method of choice, which gives efficient yield with minimum impurities. - Highlights: • Nuclear model calculations on protons on 86Sr, 88Sr and natZr using the codes ALICE-IPPE, TALYS-1.6 and EMPIRE 3.2 and evaluation of the 86Sr(p,n)86Y and 88Sr(p,3n)86Y reactions for 86Y production. • Calculation of thick target yields of 86Y and comparison with the calculated and experimental yield data given in literature. • Analysis of radionuclidic impurities in the production of 86Y. • Comparison of production routes of 86Y for medical application

  14. A rapid response time and highly sensitive amperometric glucose biosensor based on ZnO nanorod via citric acid-assisted annealing route

    Science.gov (United States)

    Yang, Zao; Ye, Zhizhen; Zhao, Binghui; Zong, Xiaolin; Wang, Ping

    2010-04-01

    ZnO nanorods were synthesized by citric acid-assisted annealing route. In a phosphate buffer solution with a pH value of 7.4, glucose oxidase was immobilized on the surface of ZnO nanorod through chitosan-assisted cross-linking technique. The one-dimensional ZnO nanorods provide a large effective surface area with high surface-to-volume ratio and provide a favorable environment for the immobilization of GO x. The response time of this biosensor is less than 2 s. This biosensor has a very high sensitivity of 25.7 μA cm -2 mM -1. The low detection limit was estimated to be 0.01 mM. Two linear response ranges are 0.01-0.25 mM and 0.3-0.7 mM. The Michaelis-Menten constant is found to be 1.95 mM. These results demonstrate that zinc oxide nanorods have potential applications in biosensors.

  15. Synthesis of Flower-Like Cu2ZnSnS4 Nanoflakes via a Microwave-Assisted Solvothermal Route

    OpenAIRE

    Fei Long; Shuyi Mo; Yan Zeng; Shangsen Chi; Zhengguang Zou

    2014-01-01

    Flower-like Cu2ZnSnS4 (CZTS) nanoflakes were synthesized by a facile and fast one-pot solution reaction using copper(II) acetate monohydrate, zinc acetate dihydrate, tin(IV) chloride pentahydrate, and thiourea as starting materials. The as-synthesized samples were characterized by X-ray diffraction (XRD), Raman scattering analysis, field emission scanning electron microscopy (FESEM) equipped with an energy dispersion X-ray spectrometer (EDS), transmission electron microscopy (TEM), and UV-Vis...

  16. Enhanced photocatalytic degradation of methylene blue by ZnO-reduced graphene oxide composite synthesized via microwave-assisted reaction

    International Nuclear Information System (INIS)

    Highlights: → ZnO-reduced graphene oxide composite is synthesized via microwave assisted reaction. → The method allows a facile, safe and rapid reaction in aqueous media. → A high dye degradation efficiency is achieved under UV light irradiation. - Abstract: A quick and facile microwave-assisted reaction is used to synthesize ZnO-reduced graphene oxide (RGO) hybrid composites by reducing graphite oxide dispersion with zinc nitrate using a microwave synthesis system. Their photocatalytic performance in degradation of methylene blue is investigated and the results show that the RGO plays an important role in the enhancement of photocatalytic performance and the ZnO-RGO composite with 1.1 wt. % RGO achieves a maximum degradation efficiency of 88% in a neutral solution under UV light irradiation for 260 min as compared with pure ZnO (68%) due to the increased light absorption, the reduced charge recombination with the introduction of RGO.

  17. Investigation of Embedded Si/C System Exposed to a Hybrid Reaction of Centrifugal-Assisted Thermite Method.

    Science.gov (United States)

    Mahmoodian, Reza; Yahya, Rosiyah; Dabbagh, Ali; Hamdi, Mohd; Hassan, Mohsen A

    2015-01-01

    A novel method is proposed to study the behavior and phase formation of a Si+C compacted pellet under centrifugal acceleration in a hybrid reaction. Si+C as elemental mixture in the form of a pellet is embedded in a centrifugal tube. The pellet assembly and tube are exposed to the sudden thermal energy of a thermite reaction resulted in a hybrid reaction. The hybrid reaction of thermite and Si+C produced unique phases. X-ray diffraction pattern (XRD) as well as microstructural and elemental analyses are then investigated. XRD pattern showed formation of materials with possible electronic and magnetic properties. The cooling rate and the molten particle viscosity mathematical model of the process are meant to assist in understanding the physical and chemical phenomena took place during and after reaction. The results analysis revealed that up to 85% of materials converted into secondary products as ceramics-matrix composite. PMID:26641651

  18. Investigation of Embedded Si/C System Exposed to a Hybrid Reaction of Centrifugal-Assisted Thermite Method.

    Directory of Open Access Journals (Sweden)

    Reza Mahmoodian

    Full Text Available A novel method is proposed to study the behavior and phase formation of a Si+C compacted pellet under centrifugal acceleration in a hybrid reaction. Si+C as elemental mixture in the form of a pellet is embedded in a centrifugal tube. The pellet assembly and tube are exposed to the sudden thermal energy of a thermite reaction resulted in a hybrid reaction. The hybrid reaction of thermite and Si+C produced unique phases. X-ray diffraction pattern (XRD as well as microstructural and elemental analyses are then investigated. XRD pattern showed formation of materials with possible electronic and magnetic properties. The cooling rate and the molten particle viscosity mathematical model of the process are meant to assist in understanding the physical and chemical phenomena took place during and after reaction. The results analysis revealed that up to 85% of materials converted into secondary products as ceramics-matrix composite.

  19. Charged particle assisted nuclear reactions in solid state environment: renaissance of low energy nuclear physics

    CERN Document Server

    Kálmán, Péter

    2015-01-01

    The features of electron assisted neutron exchange processes in crystalline solids are survayed. It is stated that, contrary to expectations, the cross section of these processes may reach an observable magnitude even in the very low energy case because of the extremely huge increment caused by the Coulomb factor of the electron assisted processes and by the effect of the crystal-lattice. The features of electron assisted heavy charged particle exchange processes, electron assisted nuclear capure processes and heavy charged particle assisted nuclear processes are also overviewed. Experimental observations, which may be related to our theoretical findings, are dealt with. The anomalous screening phenomenon is related to electron assisted neutron and proton exchange processes in crystalline solids. A possible explanation of observations by Fleischmann and Pons is presented. The possibility of the phenomenon of nuclear transmutation is qualitatively explained with the aid of usual and charged particle assisted r...

  20. Fixation of laccase enzyme into polypyrrole, assisted by chemical interaction with modified magnetite nanoparticles: A facile route to synthesize stable electroactive bionanocomposite catalysts

    International Nuclear Information System (INIS)

    Highlights: • Chemically immobilized laccase enzyme on magnetite nanoparticles is presented. • Modified nanoparticles were entrapped in conducting polymer matrix. • Bio-electrocatalytic effect was evidenced in the oxygen reduction reaction. • The method may serve as a general platform for enzyme incorporation. • New avenue for conducting polymer based biocatalytic electrodes. - Abstract: Effective bio-electrocatalysts require stable immobilization of sufficient amounts of the bioactive component. In this study, a novel and efficient method for specific binding of laccase enzyme onto magnetite nanoparticles (NPs) is presented. The interaction between the chemically modified magnetite NPs and the enzyme was evidenced by both infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). Subsequently, the enzyme-coated magnetite NPs were successfully incorporated into polypyrrole (PPy) matrix during galvanostatic electropolymerization. The encapsulation of laccase covered NPs was proved by EQCN, TEM, and FT-IR spectroscopy; whereas the electrochemical behaviour of the formed bionanocomposite was characterized by cyclic voltammetry. In oxygen saturated solution a cathodic charge surplus was observed, related to the electrochemical reduction of oxygen. This surplus was two times higher in the case of the laccase containing layer compared to its only magnetite containing counterpart. Kinetic aspects of the oxygen reduction reaction (ORR) on the laccase containing films were investigated by hydrodynamic voltammetry, and the four-electron route was found to be exclusive, which is promising from the fuel cell perspective. Such synergistic combination of inorganic NPs and enzymes may open new avenues in the application of these bio-nanocomposite materials

  1. Synthesis of Flower-Like Cu2ZnSnS4 Nanoflakes via a Microwave-Assisted Solvothermal Route

    Directory of Open Access Journals (Sweden)

    Fei Long

    2014-01-01

    Full Text Available Flower-like Cu2ZnSnS4 (CZTS nanoflakes were synthesized by a facile and fast one-pot solution reaction using copper(II acetate monohydrate, zinc acetate dihydrate, tin(IV chloride pentahydrate, and thiourea as starting materials. The as-synthesized samples were characterized by X-ray diffraction (XRD, Raman scattering analysis, field emission scanning electron microscopy (FESEM equipped with an energy dispersion X-ray spectrometer (EDS, transmission electron microscopy (TEM, and UV-Vis absorption spectra. The XRD patterns shown that the as-synthesized particles were kesterite CZTS and Raman scattering analysis and EDS confirmed that kesterite CZTS was the only phase of product. The results of FESEM and TEM show that the as-synthesized particles were flower-like morphology with the average size of 1~2 μm which are composed of 50 nm thick nanoflakes. UV-Vis absorption spectrum revealed CZTS nanoflakes with a direct band gap of 1.52 eV.

  2. Investigation of the formation of CuInS2 nanoparticles by the oleylamine route: comparison of microwave-assisted and conventional syntheses.

    Science.gov (United States)

    Pein, Andreas; Baghbanzadeh, Mostafa; Rath, Thomas; Haas, Wernfried; Maier, Eugen; Amenitsch, Heinz; Hofer, Ferdinand; Kappe, C Oliver; Trimmel, Gregor

    2011-01-01

    The formation of copper indium disulfide nanoparticles via the oleylamine route using copper iodide, indium chloride, and elemental sulfur has been investigated by applying conventional thermal heating as well as microwave irradiation. Oleylamine thereby acts as a capping ligand as well as a solvent. In an initial set of experiments, the onset of the reaction was determined to be around 115 °C by an in situ X-ray study using Synchrotron radiation. Using comparatively low synthesis temperatures of 120 °C, it is already possible to obtain nanoparticles of 2-4 nm with both heating methods but with irregular shape and size distribution. By applying higher temperatures of 220 °C, more crystalline and larger nanoparticles were obtained with slight differences in crystallite size and size distribution depending on the synthesis route. The size of the nanoparticles is in the range of 3-10 nm depending on the heating time. Using microwave irradiation, it is possible to obtain nanoparticles in only 90 s of total synthesis time. Control experiments to probe a nonthermal microwave effect were carried out ensuring an identical experimental setup, including the heating profile, the stirring rate, and the volume and concentration of the solutions. These experiments clearly demonstrate that for the preparation of CuInS(2) nanoparticles described herein no differences between conventional and microwave heating could be observed when performed at the same temperature. The nanoparticles obtained by microwave and thermal methods have the same crystal phase, primary crystallite size, shape, and size distribution. In addition, they show no significant differences concerning their optical properties. PMID:21141832

  3. Nano-sized Fe-metal catalyst on ZnO-SiO2: (photo-assisted deposition and impregnation) Synthesis routes and nanostructure characterization

    International Nuclear Information System (INIS)

    Highlights: → We prepared Fe/ZnO-SiO2 by two methods. → We tested photocatalytic activity for degradation of methylene blue dye. → We controlled band gap and size. → We found activity of Fe/ZnO-SiO2 prepared by PAD is hightest photocatalytic activity. - Abstract: A nano-sized Fe metal on ZnO-SiO2 was synthesized using the photo-assisted deposition (PAD) and impregnation routes. The obtained samples were characterized by a series of techniques including X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy, N2 adsorption, extended X-ray absorption fine structure (EXAFS), and transmission electron microscopy (TEM). Photocatalytic reactivity using Fe-ZnO-SiO2 catalysts under visible-light condition on the degradation of methylene blue dye was evaluated. The results of characterization reveal, a notable photocatalytic activity of PAD:Fe-ZnO-SiO2 which was about 9 and 12 times higher than that of Img:Fe-ZnO-SiO2 and ZnO-SiO2, respectively.

  4. A simple route utilizing surfactant-assisted templating sol-gel process for synthesis of mesoporous Dy2O3 nanocrystal.

    Science.gov (United States)

    Sreethawong, Thammanoon; Chavadej, Sumaeth; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

    2006-08-01

    A simple route of combined sol-gel process with surfactant-assisted templating technique was successfully employed for the first time to synthesize nanocrystalline mesoporous Dy(2)O(3) with narrow monomodal pore size distribution under mild conditions. The nanocrystalline Dy(2)O(3) with monomodal mesoporous characteristic was ultimately achieved by controlling the hydrolysis and condensation steps of dysprosium n-butoxide modified with acetylacetone in the presence of laurylamine hydrochloride surfactant aqueous solution. The synthesized material was methodically characterized by thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), N(2) adsorption-desorption, Brunauer-Emmett-Teller (BET) surface area analysis, and Barrett-Joyner-Halenda (BJH) pore size distribution analysis. The particle size of the synthesized Dy(2)O(3) in nanosized range obtained from the SEM and HRTEM micrographs was in good accordance with the crystallite size estimated from the XRD result. The N(2) adsorption-desorption result exhibited hysteresis pattern with single loop, indicating the existence of monomodal mesopore. The extremely narrow pore size distribution with mean pore diameter in the mesopore region of the synthesized Dy(2)O(3) was also confirmed by the BJH result. PMID:16647076

  5. Preparation of nanocrystalline MnFe2O4 by doping with Ti4+ ions using solid-state reaction route

    International Nuclear Information System (INIS)

    Nanostructured manganese ferrites (MnFe2O4) with diameters in the range of 45-30 nm were synthesized by Ti4+ ion doping, using conventional solid-state reaction route. The substitution of Ti4+ ions created vacancies at Mn2+ sites and the coupling of ferrimagnetically active oxygen polyhedra was broken. This created nanoscale regions of ferrites. A reduction of magnetization for decreasing particle size was observed. Coercivity showed an increasing trend. This was explained as arising due to multidomain/monodomain magnetic behaviour of magnetic nanoparticles. DC resistivities of the doped specimens indicated the presence of an interfacial amorphous phase formed by the nanoparticles. Zero-field cooled and field-cooled curves from 30 nm sized particles showed a peak at T B (∼125 K), typical of superparamagnetic blocking temperature

  6. Catalytic synthesis of 2-methylpyrazine over Cr-promoted copper based catalyst via a cyclo-dehydrogenation reaction route

    Indian Academy of Sciences (India)

    Fangli Jing; Yuanyuan Zhang; Shizhong Luo; Wei Chu; Hui Zhang; Xinyu Shi

    2010-07-01

    The cyclo-dehydrogenation of ethylene diamine and propylene glycol to 2-methylpyrazine was performed under the atmospheric conditions at 380°C. The Cr-promoted Cu-Zn/Al2O3 catalysts were prepared by impregnation method and characterized by ICP-AES, N2 adsorption/desorption, XRD, XPS, N2O chemisorption, TPR and NH3-TPD techniques. The amorphous chromium species existing in Cu-Zn-Cr/Al2O3 catalyst enhanced the dispersion of active component Cu, promoted the reduction of catalyst. Furthermore, the catalytic performance was significantly improved. The acidity of the catalyst played an important role in increasing the 2-MP selectivity. To optimize the reaction parameters, influences of different chromium content, reaction temperature, liquid hourly space velocity (LHSV), reactants molar ratio and time on stream on the product pattern were studied. The results demonstrated that addition of chromium promoter revealed satisfying catalytic activity, stability and selectivity of 2-methylpyrazine.

  7. A Convenient Route to Higher Sugars by Two-Carbon Chain Elongation Using Wittig/Dihydroxylation Reactions

    DEFF Research Database (Denmark)

    Jørgensen, Morten; Iversen, Erik Høgh; Madsen, Robert

    2001-01-01

    )-configured alpha,beta -unsaturated esters as the only products in most cases. These are dihydroxylated in a diastereoselective fashion using OsO4/NMO. The stereochemical outcome in the dihydroxylation follows Kishi's empirical rule and gives high diastereoselectivity (5:1-8:1) when starting from sugars with the 2......The combination of a Wittig olefination and a dihydroxylation reaction constitutes a facile synthetic protocol for the transformation of unprotected carbohydrates into higher sugars. The Wittig reaction is carried out with tert-butyl or diphenylmethyl ester stabilized phosphoranes to give (E......,3-threo configuration. When starting from sugars with the 2,3-erythro configuration, the diastereoselectivity in the dihydroxylation is low (2:1-2.5:1). As a result, the Wittig/dihydroxylation protocol is most effective for producing higher sugars with the galacto configuration at the reducing end. The...

  8. Peptides Quantification by Liquid Chromatography with Matrix-Assisted Laser Desorption/Ionization and Selected Reaction Monitoring Detection

    OpenAIRE

    Lesur, Antoine; Varesio, Emmanuel; Domon, Bruno; Hopfgartner, Gérard

    2012-01-01

    We present a novel analytical platform for peptides quantitative assays in biological matrices based on microscale liquid chromatography fractionation and matrix-assisted laser desorption/ionization mass spectrometric detection using the selected reaction monitoring (SRM) mode. The MALDI source was equipped with a high frequency Nd:YAG laser (1000 Hz) and mounted on a triple quadrupole / linear ion trap mass spectrometer (MALDI-QqQLIT). Compared to conventional LC-ESI-SRM/MS, the separated an...

  9. Radical-Molecule Reaction C3H + H2O on Amorphous Water Ice: A Promising Route for Interstellar Propynal

    Science.gov (United States)

    Xie, Hong-bin; Shao, Chang-bin; Ding, Yi-hong

    2007-11-01

    Intriguing propynal (HCCCHO) has been attracting chemist's attention since 1955. However, to date, no satisfying conclusion concerning its formation mechanism in the interstellar medium (ISM) has been reached, although a variety of gas-reaction models, including ion-molecule, radical-molecule, and molecule-molecule, have been postulated. In this paper, we consider for the first time the gas-grain interaction model that involves heterogeneous reaction at the surface of dust grain or in the icy mantles to account for the propynal's formation. Based on the detailed density functional theory (DFT) and Gaussian-3 potential energy surface studies, we found that although the gaseous process C3H+H2O-->propynal+H must surmount a considerable entrance barrier (around 10 kcal mol-1), amorphous water ice can significantly catalyze the propynal's formation to be barrierless. So, this model should be a more reasonable one for propynal's formation in the low-temperature interstellar space. This result may also represent one rare case of the water-catalyzed reaction associated with a molecular radical in space. Future experimental studies are greatly desired to probe such interesting processes.

  10. Expedited Synthesis of Benzofuran-2-Carboxylic Acids via Microwave-Assisted Perkin Rearrangement Reaction

    OpenAIRE

    Marriott, Karla-Sue C.; Bartee, Rena; Morrison, Andrew Z.; Stewart, Leonard; Wesby, Julian

    2012-01-01

    3-Halocoumarins are readily converted into benzofuran-2-carboxylic acids via a Perkin (coumarin-benzofuran ring contraction) rearrangement reaction. This rearrangement entails initial base catalyzed ring fission. The resulting phenoxide anion then attacks a vinyl halide to produce the final benzofuran moiety. We explored this reaction under microwave reaction conditions and were able to significantly reduce reaction times as well as obtain very high yields of a series of benzofuran-2-carboxyl...

  11. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Webler, Geovana D. [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Correia, Ana C.C.; Barreto, Emiliano [Laboratório de Biologia Celular, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Fonseca, Eduardo J.S., E-mail: eduardo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil)

    2015-07-15

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity.

  12. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    International Nuclear Information System (INIS)

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity

  13. A Self-Propagating Foaming Process of Porous Al-Ni Intermetallics Assisted by Combustion Reactions

    Directory of Open Access Journals (Sweden)

    Makoto Kobashi

    2009-12-01

    Full Text Available The self-propagating foaming process of porous Al-Ni intermetallics was investigated. Aluminum and nickel powders were blended, and titanium and boron carbide powders were added as reactive exothermic agents. The blended powder was extruded to make a rod-shape precursor. Only one end of the rod precursor was heated to ignite the reaction. The reaction propagated spontaneously throughout the precursor. Pore formation took place at the same time as the reaction occurred. Adding the exothermic agent was effective to increase the porosity. Preheating the precursor before the ignition was also very effective to produce porous Al-Ni intermetallics with high porosity.

  14. Study on absorbance and laser damage threshold of HfO2 films prepared by ion-assisted reaction deposition

    Institute of Scientific and Technical Information of China (English)

    张大伟; 范树海; 高卫东; 贺洪波; 王英剑; 邵建达; 范正修; 孙浩杰

    2004-01-01

    Using a new kind of EH1000 ion source, hafnium dioxide (HfO2) films are deposited with different depo sition techniques and different conditions. The absorbance and the laser damage threshold of these films have been measured and studied. By comparing these characteristics, one can conclude that under right conditions, such as high partial pressure of oxygen and right kind of ion source, the ion-assisted reaction deposition can prepare HfO2 films with higher laser induced damage threshold.

  15. Efficient and ‘green’ microwave-assisted synthesis of haloalkylphosphonates via Michaelis-Arbuzov reaction

    Czech Academy of Sciences Publication Activity Database

    Česnek, Michal; Jansa, Petr; Holý, Antonín; Dračínský, Martin; Baszczyňski, Ondřej; Janeba, Zlatko

    Lanzarote : -, 2012. s. 50-50. [Zing Conferences: Microwave and Flow Conference. 28.02.2012-02.03.2012, Lanzarote] R&D Projects: GA MŠk 1M0508; GA AV ČR 1QS400550501 Institutional research plan: CEZ:AV0Z40550506 Keywords : microwave-assisted * Michaelis Arbuzov * phosphonates Subject RIV: CC - Organic Chemistry

  16. Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

    Directory of Open Access Journals (Sweden)

    Rita M. Borik

    2007-08-01

    Full Text Available The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

  17. Microwave-Assisted Reaction in Green Solvents Recycles PHB to Functional Chemicals

    OpenAIRE

    Yang, Xi; Odelius, Karin; Hakkarainen, Minna

    2014-01-01

    An efficient microwave-assisted process for chemical recycling of poly(3-hydroxybutyrate) (PHB) in green solvents was demonstrated. Previously, PHB has been thermally recycled to crotonic acid and unsaturated oligomers. Our aim was to utilize green solvents (water, methanol, and ethanol) under alkaline conditions to achieve fast hydrolysis and monomeric or oligomeric degradation products with carboxyl and hydroxyl or methoxy or ethoxy end groups. Preliminary screening confirmed that the most ...

  18. Microwave Assisted Reactions in Organic Chemistry: A Review of Recent Advances

    OpenAIRE

    Jolly Jacob

    2012-01-01

    Revolution in organic compound synthesis has been promoted by microwave assisted organic syntheses (MAOS) by which small molecules are built up into large polymers in a fraction of time. The need for different organic compound libraries for drug discovery, biomaterial development, automated library screening; proteomics etc has supported the emergence of innovative technologies for rapid combinatorial organic synthesis using MAOS synthesis. In previous reviews on this subject the focus of MAO...

  19. Optimization of the production of ethyl esters by ultrasound assisted reaction of soybean oil and ethanol

    Directory of Open Access Journals (Sweden)

    S. Rodrigues

    2009-06-01

    Full Text Available Biodiesel is a renewable liquid fuel that can be produced by a transesterification reaction between a vegetable oil and an alcohol. This paper evaluates and optimizes the production of ethyl esters (biodiesel from soybean oil and ethanol. The reaction was carried out by applying ultrasound under atmospheric pressure and ambient temperature. Response surface methodology was used to evaluate the influence of alcohol to oil molar ratio and catalyst concentration on the yield of conversion of soybean oil into ethyl esters. The process resulted in a maximum yield of 91.8% after 30 minutes of reaction. The process variables alcohol to oil ratio and catalyst to oil ratio were statistically significant regarding the yield of ethyl esters. The optimal operating condition was obtained applying an alcohol to oil molar ratio of 10.2 and a catalyst to oil weight ratio of 0.0035.

  20. Synthesis of BaTiO3 powders by a ball milling-assisted hydrothermal reaction

    International Nuclear Information System (INIS)

    The effects of ball milling during the hydrothermal BaTiO3 synthesis from nano- and sub-micron sized TiO2 powders were studied. The synthesized BaTiO3 powders were characterized by X-ray diffraction (XRD), a laser light scattering particle size distribution analyzer, and field emission scanning electron microscopy (FE-SEM). The XRD patterns showed that BaTiO3 powders could be synthesized using the ball milling system at 100 deg. C and for 5 h with little contamination. The BaTiO3 powders observed by FE-SEM were agglomerated. The agglomerated particle sizes of BaTiO3 prepared from nano- and sub-miron sized TiO2 particles were 152 ± 42 and 148 ± 21 nm, respectively. Furthermore, it was found that the rate constant of BaTiO3 powder prepared from Ba(OH)2 and sub-micrometer sized TiO2 powder with the ball milling process was twice as large compared to a hydrothermal route without ball milling

  1. Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

    Institute of Scientific and Technical Information of China (English)

    Salah ALJBOUR; Tomohiko TAGAWA; Mohammad MATOUQ; Hiroshi YAMADA

    2009-01-01

    The Lewis acid-catalyzed addition of tri-methylsilyl cyanide to p-chlorobenzaldehyde in a micro-channel reactor was investigated. The microchannel was integrated to promote both reaction and separation of the biphase system. FeF3 and Cu(triflate)2 were used as water-stable Lewis acid catalysts. Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphase flow inside the microchannel. It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system. Parallel multiphase flow inside the microchannel was obtained, allowing for continuous and acceptable phase separation. Enhanced selectivity was achieved by operating at lower conversion values.

  2. ATP hydrolysis assists phosphate release and promotes reaction ordering in F1-ATPase

    Science.gov (United States)

    Li, Chun-Biu; Ueno, Hiroshi; Watanabe, Rikiya; Noji, Hiroyuki; Komatsuzaki, Tamiki

    2015-12-01

    F1-ATPase (F1) is a rotary motor protein that can efficiently convert chemical energy to mechanical work of rotation via fine coordination of its conformational motions and reaction sequences. Compared with reactant binding and product release, the ATP hydrolysis has relatively little contributions to the torque and chemical energy generation. To scrutinize possible roles of ATP hydrolysis, we investigate the detailed statistics of the catalytic dwells from high-speed single wild-type F1 observations. Here we report a small rotation during the catalytic dwell triggered by the ATP hydrolysis that is indiscernible in previous studies. Moreover, we find in freely rotating F1 that ATP hydrolysis is followed by the release of inorganic phosphate with low synthesis rates. Finally, we propose functional roles of the ATP hydrolysis as a key to kinetically unlock the subsequent phosphate release and promote the correct reaction ordering.

  3. Aqueous microwave-assisted cross-coupling reactions applied to unprotected nucleosides

    Science.gov (United States)

    Hervé, Gwénaëlle; Len, Christophe

    2015-01-01

    Metal catalyzed cross-coupling reactions have been the preferred tools to access to modified nucleosides (on the C5-position of pyrimidines and on the C7- or C8-positions of purines). Our objective is to focus this mini-review on the Suzuki-Miyaura and on the Heck cross-couplings of nucleosides using microwave irradiations which is an alternative technology compatible with green chemistry and sustainable development PMID:25741506

  4. Solar thermal polymerase chain reaction for smartphone-assisted molecular diagnostics

    OpenAIRE

    Li Jiang; Matthew Mancuso; Zhengda Lu; Gunkut Akar; Ethel Cesarman; David Erickson

    2014-01-01

    Nucleic acid-based diagnostic techniques such as polymerase chain reaction (PCR) are used extensively in medical diagnostics due to their high sensitivity, specificity and quantification capability. In settings with limited infrastructure and unreliable electricity, however, access to such devices is often limited due to the highly specialized and energy-intensive nature of the thermal cycling process required for nucleic acid amplification. Here we integrate solar heating with microfluidics ...

  5. A microwave-assisted and heteropolyacids-catalysed cyclocondensation reaction for the synthesis of 4(3H)-quinazolinones.

    Science.gov (United States)

    Ighilahriz, Karima; Boutemeur, Baya; Chami, Fariza; Rabia, Cherifa; Hamdi, Maâmar; Hamdi, Safouane M

    2008-01-01

    We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction. PMID:18463579

  6. Chemo-selective high yield microwave assisted reaction turns cellulose to green chemicals.

    Science.gov (United States)

    Hassanzadeh, Salman; Aminlashgari, Nina; Hakkarainen, Minna

    2014-11-01

    Exceptionally high cellulose liquefaction yields, up to 87% as calculated from the amount of solid residue, were obtained under mild conditions by utilizing the synergistic effect of microwave radiation and acid catalysis. The effect of processing conditions on degradation products was fingerprinted by rapid laser desorption ionization-mass spectrometry (LDI-MS) method. The reaction was chemo-tunable, enabling production of glucose (Glc) or levulinic acid (LeA) at significantly high selectivity and yields, the relative molar yields being up to 50 and 69%, respectively. A turning point from pure depolymerization to glucose to further degradation to levulinic acid and formic acid was observed at approximately 50% liquefaction or above 140 °C. This was accompanied by the formation of small amounts of solid spherical carbonized residues. The reaction was monitored by multiple analytical techniques. The high yields were connected to the ability of the process to break the strong secondary interactions in cellulose. The developed method has great potential for future production of green platform chemicals. PMID:25129766

  7. Microwave-assisted digestion procedures for biological samples with diluted nitric acid: identification of reaction products.

    Science.gov (United States)

    Gonzalez, Mário H; Souza, Gilberto B; Oliveira, Regina V; Forato, Lucimara A; Nóbrega, Joaquim A; Nogueira, Ana Rita A

    2009-07-15

    Microwave-assisted sample preparation using diluted nitric acid solutions is an alternative procedure for digesting organic samples. The efficiency of this procedure depends on the chemical properties of the samples and in this work it was evaluated by the determination of crude protein amount, fat and original carbon. Soybeans grains, bovine blood, bovine muscle and bovine viscera were digested in a cavity-microwave oven using oxidant mixtures in different acid concentrations. The digestion efficiency was evaluated based on the determination of residual carbon content and element recoveries using inductively coupled plasma optical emission spectrometry (ICP OES). In order to determine the main residual organic compounds, the digests were characterized by nuclear magnetic resonance ((1)H NMR). Subsequently, studies concerning separation of nitrobenzoic acid isomers were performed by ion pair reversed phase liquid chromatography using a C18 stationary phase, water:acetonitrile:methanol (75:20:5, v/v/v)+0.05% (v/v) TFA as mobile phase and ultraviolet detection at 254 nm. Sample preparation based on diluted acids proved to be feasible and a recommendable alternative for organic sample digestion, reducing both the reagent volumes and the variability of the residues as a result of the process of decomposition. It was shown that biological matrices containing amino acids, proteins and lipids in their composition produced nitrobenzoic acid isomers and other organic compounds after cleavage of chemical bonds. PMID:19559896

  8. Analysis and modeling of gas-phase reactions at plasma-assisted diamond and synthesis techniques

    International Nuclear Information System (INIS)

    Low-pressure growth of diamond is a relatively new technique increasingly used for producing diamond coatings and heat sinks. The physical and chemical processes involved can be divided into the gas-phase reactions and the processes at the surface. In this work the gas-phase kinetics of different gas mixtures is investigated. Kinetic modeling as well as the results of time resolved mass spectrometric investigations are used for this purpose. Gas mixtures for low-pressure diamond synthesis consist of small admixtures of hydrocarbons to hydrogen. The addition of oxygen containing species can speed up growth and increase the quality of diamond films. The calculations and experiments were performed with various types of feed gas compositions with and without-oxygen. For this purpose two gas-phase mechanisms were developed which include 15 species in the case of hydrogen/hydrocarbon-mixtures und 23 species when oxygen is present. Modeling was performed using the Chemkin computer code. An electrodeless rf plasma sustained in a quartz tube is the centerpiece of the experimental set-up for mass spectrometric measurements. The gas composition is analyzed by a quadrupole mass spectrometer. The measured mole fractions of Cl4, C2H2, C21H4 and C2H6 are corrected for the reactions inside the probe system and compared with the results of kinetic modeling. Mole fractions of instable species can be derived from the calculations as well. Additionally a model for the gas-phase kinetics of a plasmajet is described. It takes into account the gas recirculation in the deposition chamber. The methyl radical is found to be the dominating species in the jet close to the nozzle, where atomic carbon is the most prominent species at greater distances. Using a growth-model diamond deposition rates are estimated and compared with measured diamond growth. (author)

  9. Synthesis of aluminum nitride powders from a plasma-assisted ball milled precursor through carbothermal reaction

    International Nuclear Information System (INIS)

    Highlights: • A novel and high efficiency synthesizing AlN powders method combining mechanical ball milling and DBDP has been developed. • The particle size, the crystallite size, the lattice distortion, the morphology of Al2O3 powders, and the AlN conversion rate are investigated and compared under the ball milled Al2O3 powders with DBDP and without DBDP. • The ball milled Al2O3 powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. - Abstract: In this paper, aluminum nitride (AlN) powers have been produced with a novel and high efficiency method by thermal annealing at 1100–1600 °C of alumina (Al2O3) powders which were previously ball milled for various time up to 40 h with and without the assistant of dielectric barrier discharge plasma (DBDP). The ball milled Al2O3 powders with DBDP and without DBDP and the corresponding synthesized AlN powers are characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. From the characteristics of the ball milled Al2O3 powders with DBDP and without DBDP, it can be seen that the ball milled Al2O3 powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. Meanwhile, the synthesized AlN powders can be known as hexagonal AlN with fine crystal morphology and irregular lump-like structure, and have uniform distribution with the average particle size of about between 500 nm and 1000 nm. This provides an important method for fabricating ultra fine powders and synthesizing nitrogen compounds

  10. Hydrophilic group formation and cell culturing on polystyrene Petri-dish modified by ion-assisted reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-Hwan E-mail: hama@kist.re.kr; Cho, Jun-Sik; Choi, Doo-Jin; Koh, Seok-Keun

    2001-04-01

    Polystyrene (PS) Petri-dishes were modified by an ion-assisted reaction (IAR) to improve wettability and to supply a suitable surface for cell culturing. Low energy Ar{sup +} ions with 1000 eV were irradiated on the surface of PS in oxygen gas environment. Water contact angles of PS were not reduced much by ion irradiation without oxygen gas and had a value of 40 deg. In the case of ion irradiation with flowing oxygen gas, however, the water contact angles were dropped significantly from 73 deg. to 19 deg. X-ray photoelectron spectroscopy analysis showed that the hydrophilic groups were formed on the surface of PS by a chemical reaction between unstable chains induced by ion irradiation and the oxygen gas. Newly formed hydrophilic groups were identified as -(C-O)-, -(C=O)- and -(C=O)-O- bonds. The influence of the surface modification on growth of the rat pheochromocytoma (PC12) cells was investigated. The IAR-treated PS surfaces showed enhanced attachment and growth in PC12 cell culture test.

  11. Comparative study on upconversion luminescence and temperature sensing of α- and β-NaYF4:Yb3+/Er3+ nano-/micro-crystals derived from a microwave-assisted hydrothermal route

    International Nuclear Information System (INIS)

    Yb3+/Er3+ co-doped α- and β-phase NaYF4 nano-/micro-crystals were prepared through a microwave-assisted hydrothermal route. The crystal structure and microscopic morphology of the samples were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Frequency upconverted emissions from the two thermally coupled excited state 2H11/2 and 4S3/2 levels of Er3+ in both phases of phosphors were recorded at temperatures ranging from room temperature to 573 K under 980 nm infrared laser excitation. The time scanning upconversion spectra were investigated in detail to reveal the thermal effect induced by laser irradiation and the luminescent thermal stability of the two phases NaYF4 polycrystals. Comparison of the upconversion luminescence and the sensitivity between the two phases NaYF4 polycrystals indicated that β-phase NaYF4 won much stronger luminescent intensity, better luminescent thermal stability, and higher temperature sensitivity. - Highlights: • Yb3+/Er3+ codoped NaYF4 were prepared by a microwave-assisted hydrothermal route. • The UC luminescence and temperature sensing properties were studied. • Comparison of the UCL and the sensitivity between α- and β-phase samples were done. • Thermal effect and UCL thermo-stability were studied by time scanning UCL spectra. • β-phase sample won much better luminescent and temperature sensing properties

  12. Solar thermal polymerase chain reaction for smartphone-assisted molecular diagnostics

    Science.gov (United States)

    Jiang, Li; Mancuso, Matthew; Lu, Zhengda; Akar, Gunkut; Cesarman, Ethel; Erickson, David

    2014-02-01

    Nucleic acid-based diagnostic techniques such as polymerase chain reaction (PCR) are used extensively in medical diagnostics due to their high sensitivity, specificity and quantification capability. In settings with limited infrastructure and unreliable electricity, however, access to such devices is often limited due to the highly specialized and energy-intensive nature of the thermal cycling process required for nucleic acid amplification. Here we integrate solar heating with microfluidics to eliminate thermal cycling power requirements as well as create a simple device infrastructure for PCR. Tests are completed in less than 30 min, and power consumption is reduced to 80 mW, enabling a standard 5.5 Wh iPhone battery to provide 70 h of power to this system. Additionally, we demonstrate a complete sample-to-answer diagnostic strategy by analyzing human skin biopsies infected with Kaposi's Sarcoma herpesvirus (KSHV/HHV-8) through the combination of solar thermal PCR, HotSHOT DNA extraction and smartphone-based fluorescence detection. We believe that exploiting the ubiquity of solar thermal energy as demonstrated here could facilitate broad availability of nucleic acid-based diagnostics in resource-limited areas.

  13. Study on microwave-assisted Michael reaction of phosphorus ylides%新型微波辅助磷叶立德Michael加成反应研究

    Institute of Scientific and Technical Information of China (English)

    张龚; 杨一思; 徐晴霞

    2012-01-01

    The microwave-assisted Michael addition reaction of stabilized phosphorus ylides and nitroole-fins and then the Wittig reaction of the intermediate and formaldehyde were studied. The product yield of 78. 1% was attained under the optimized condition. Compared with ordinary reaction,the reaction time under the condition of microwave assistance was obviously shortened and the product yield was higher.%微波条件下,磷叶立德与硝基烯烃发生Michael加成反应,然后中间体与甲醛发生Wittig反应,得到γ-氨基酸前驱体.经过条件筛选,反应收率可达78.1%.微波条件下的反应时间明显少于常规反应时间,且收率更高.

  14. Cu{sub 2}ZnSnS{sub 4} thin films by simple replacement reaction route for solar photovoltaic application

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Devendra, E-mail: devendratiwari.rnd@ecchanga.ac.in [Dr. K. C. Patel Research and Development Centre, Charotar University of Science and Technology, Changa, Anand District, Gujarat 388421 (India); Chaudhuri, Tapas K. [Dr. K. C. Patel Research and Development Centre, Charotar University of Science and Technology, Changa, Anand District, Gujarat 388421 (India); Ray, Arabinda [P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa, Anand District, Gujarat 388421 (India); Tiwari, Krishan Dutt [Powerdeal Energy Systems - India, Private Limited, Nashik 422010, Maharashtra (India)

    2014-01-31

    A process for deposition of Cu{sub 2}ZnSnS{sub 4} (CZTS) films using replacement of Zn{sup 2+} in ZnS is demonstrated. X-ray diffraction pattern and Raman spectroscopy confirm the formation of pure CZTS. Atomic force microscopy shows the films to be homogeneous and compact with root mean squared roughness of 6 nm. The direct band gap of CZTS films as elucidated by UV–Vis-NIR spectroscopy is 1.45 eV. The CZTS films exhibit p-type conduction with electrical conductivity of 4.6 S/cm. The hole concentration and hole mobility is determined to be 3.6 × 10{sup 17} cm{sup −3} and 1.4 cm{sup 2}V{sup −1} s{sup −1} respectively. Solar cells with structure: graphite/CZTS/CdS/ZnO/SnO{sub 2}:In/Soda lime glass are also fabricated, gave photo-conversion efficiency of 6.17% with open circuit voltage and short circuit current density of 521 mV and 19.13 mA/cm{sup 2}, respectively and a high fill factor of 0.62. The external quantum efficiency of the solar cell lies above 60% in the visible region. - Highlights: • Pure kesterite Cu{sub 2}ZnSnS{sub 4} thin films deposited by replacement reaction route • Energy band gap of films is 1.45 eV. • p-type films with conductivity of 4.6 S/cm and mobility of 1.4 cm{sup 2} S{sup −1} V{sup −1} • Fabrication of Graphite/Cu{sub 2}ZnSnS{sub 4}/CdS/ZnO/SnO{sub 2}:In/Glass solar cell • Solar cell delivered efficiency of 6.17% with high fill factor of 0.62.

  15. Synthesis of aluminum nitride powders from a plasma-assisted ball milled precursor through carbothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhi-jie [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Dai, Le-yang [Marine Engineering Institute, Jimei University, Xiamen 361021 (China); Yang, De-zheng; Wang, Sen [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Zhang, Bao-jian [Marine Engineering Institute, Jimei University, Xiamen 361021 (China); Wang, Wen-chun, E-mail: wangwenc@dlut.edu.cn [Key Lab of Materials Modification (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Cheng, Tie-han [Pinggao Group Co. Ltd., State Grid Corporation of China, Pingdingshan 467000 (China)

    2015-01-15

    Highlights: • A novel and high efficiency synthesizing AlN powders method combining mechanical ball milling and DBDP has been developed. • The particle size, the crystallite size, the lattice distortion, the morphology of Al{sub 2}O{sub 3} powders, and the AlN conversion rate are investigated and compared under the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP. • The ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. - Abstract: In this paper, aluminum nitride (AlN) powers have been produced with a novel and high efficiency method by thermal annealing at 1100–1600 °C of alumina (Al{sub 2}O{sub 3}) powders which were previously ball milled for various time up to 40 h with and without the assistant of dielectric barrier discharge plasma (DBDP). The ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP and the corresponding synthesized AlN powers are characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. From the characteristics of the ball milled Al{sub 2}O{sub 3} powders with DBDP and without DBDP, it can be seen that the ball milled Al{sub 2}O{sub 3} powders with DBDP have small spherical structure morphology with very fine particles size and high specific surface area, which result in a higher chemical efficiency and a higher AlN conversion rate at lower thermal temperature. Meanwhile, the synthesized AlN powders can be known as hexagonal AlN with fine crystal morphology and irregular lump-like structure, and have uniform distribution with the average particle size of about between 500 nm and 1000 nm. This provides an important method for fabricating ultra fine powders and synthesizing nitrogen compounds.

  16. Degradation of Corn Oil Wastes by Fenton Reaction and Under Mildly Basic Media in the Presence of Oxidants Assisted with Sun Light

    OpenAIRE

    Josefina V.  Sanchez; Susana S.  Martinez; Maria D.F.T.  Hernandez

    2008-01-01

    The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also under mildly basic media in the presence of oxidants, such as hydrogen peroxide and persulfate, assisted with solar light. The degradation efficiency was obtained by analysis of chemical oxygen demand, carbon dioxide and gas chromatography. Over 90% of both chemical oxygen demand abatement and carbon dioxide recovery was accomplished by Fenton reaction. The presence of oxidants during the photodegrada...

  17. An Unexpected Green and Facile Synthesis of 2,6-Diaryl-4-styrylpyridines via Multi-component Reactions in Microwave-assisted Solvent-free Conditions

    Institute of Scientific and Technical Information of China (English)

    SHI Feng; ZHANG Ge; ZHOU Dianxiang; MA Ning; ZHANG Yajie; CHEN Rongshun; TU Shujiang

    2009-01-01

    An unexpected green and facile synthesis of 2,6-diaryl-4-styryipyridines was realized via microwave-assisted multi-component reactions of 3-arylacrylaldehyde oximes,l-arylethanones and ammonium acetate in solvent-free conditions.This protocol has the prominent advantages of environmental-friendliness,short reaction time,high yields,low cost,easy operation as well as broad scope of applicability.

  18. Scalable graphene synthesised by plasma-assisted selective reaction on silicon carbide for device applications

    Science.gov (United States)

    Tsai, Hsu-Sheng; Lai, Chih-Chung; Medina, Henry; Lin, Shih-Ming; Shih, Yu-Chuan; Chen, Yu-Ze; Liang, Jenq-Horng; Chueh, Yu-Lun

    2014-10-01

    Graphene, a two-dimensional material with honeycomb arrays of carbon atoms, has shown outstanding physical properties that make it a promising candidate material for a variety of electronic applications. To date, several issues related to the material synthesis and device fabrication need to be overcome. Despite the fact that large-area graphene films synthesised by chemical vapour deposition (CVD) can be grown with relatively few defects, the required transfer process creates wrinkles and polymer residues that greatly reduce its performance in device applications. Graphene synthesised on silicon carbide (SiC) has shown outstanding mobility and has been successfully used to develop ultra-high frequency transistors; however, this fabrication method is limited due to the use of costly ultra-high vacuum (UHV) equipment that can reach temperatures over 1500 °C. Here, we show a simple and novel approach to synthesise graphene on SiC substrates that greatly reduces the temperature and vacuum requirements and allows the use of equipment commonly used in the semiconductor processing industry. In this work, we used plasma treatment followed by annealing in order to obtain large-scale graphene films from bulk SiC. After exposure to N2 plasma, the annealing process promotes the reaction of nitrogen ions with Si and the simultaneous condensation of C on the surface of SiC. Eventually, a uniform, large-scale, n-type graphene film with remarkable transport behaviour on the SiC wafer is achieved. Furthermore, graphene field effect transistors (FETs) with high carrier mobilities on SiC were also demonstrated in this study.Graphene, a two-dimensional material with honeycomb arrays of carbon atoms, has shown outstanding physical properties that make it a promising candidate material for a variety of electronic applications. To date, several issues related to the material synthesis and device fabrication need to be overcome. Despite the fact that large-area graphene films

  19. Scalable graphene synthesised by plasma-assisted selective reaction on silicon carbide for device applications.

    Science.gov (United States)

    Tsai, Hsu-Sheng; Lai, Chih-Chung; Medina, Henry; Lin, Shih-Ming; Shih, Yu-Chuan; Chen, Yu-Ze; Liang, Jenq-Horng; Chueh, Yu-Lun

    2014-11-21

    Graphene, a two-dimensional material with honeycomb arrays of carbon atoms, has shown outstanding physical properties that make it a promising candidate material for a variety of electronic applications. To date, several issues related to the material synthesis and device fabrication need to be overcome. Despite the fact that large-area graphene films synthesised by chemical vapour deposition (CVD) can be grown with relatively few defects, the required transfer process creates wrinkles and polymer residues that greatly reduce its performance in device applications. Graphene synthesised on silicon carbide (SiC) has shown outstanding mobility and has been successfully used to develop ultra-high frequency transistors; however, this fabrication method is limited due to the use of costly ultra-high vacuum (UHV) equipment that can reach temperatures over 1500 °C. Here, we show a simple and novel approach to synthesise graphene on SiC substrates that greatly reduces the temperature and vacuum requirements and allows the use of equipment commonly used in the semiconductor processing industry. In this work, we used plasma treatment followed by annealing in order to obtain large-scale graphene films from bulk SiC. After exposure to N2 plasma, the annealing process promotes the reaction of nitrogen ions with Si and the simultaneous condensation of C on the surface of SiC. Eventually, a uniform, large-scale, n-type graphene film with remarkable transport behaviour on the SiC wafer is achieved. Furthermore, graphene field effect transistors (FETs) with high carrier mobilities on SiC were also demonstrated in this study. PMID:25307846

  20. Mechanochemically assisted room temperature solid state metathesis reaction for the synthesis of MMoO4 (M = Ca, Sr and Ba)

    Indian Academy of Sciences (India)

    Purnendu Parhi; Satya Sadhan Singh; Alok R Ray; A Ramanan

    2006-04-01

    This communication reports a novel mechanochemically assisted room temperature solid state metathesis reaction for the synthesis of submicron-size alkaline-earth molybdates crystallizing in a tetragonal Scheelite structure. The solids were characterized by powder XRD, FTIR, TGA, DTA, SEM, EDAX and TEM to ascertain their composition, phase homogeneity and morphology.

  1. New data on cross-sections of deuteron induced nuclear reactions on gold up to 50 MeV and comparison of production routes of medically relevant Au and Hg radioisotopes

    CERN Document Server

    Tárkányi, F; Ditrói, F; Takács, S; Adam-Rebeles, R

    2016-01-01

    Investigations of cross-sections of deuteron induced nuclear reactions on gold were extended up to 50 MeV by using the standard stacked foil irradiation technique and high resolution gamma-ray spectrometry. New cross-sections are reported for the $^{197}$Au(d,xn)$^{197m,197g,195m,195g,193m,193g}$Hg and $^{197}$Au(d,x)$^{198m,198g,196m,196g,195,194}$Au nuclear reactions. The application for production of the medically relevant isotopes $^{198}$Au and $^{195m,195g,197m,197g}$Hg is discussed, including the comparison with other charged particle induced production routes. The possible use of the $^{197}$Au(d,x)$^{197m,197g,195m,193m}$Hg and $^{196m,196g}$Au reactions for monitoring deuteron beam parameters is also investigated.

  2. Dehydrogenation inhibition on nano-Au/ZSM-5 catalyst: a novel route for anti-coking in methanol to propylene reaction.

    Science.gov (United States)

    Sun, Chao; Yang, Yisu; Du, Junming; Qin, Feng; Liu, Zhipan; Shen, Wei; Xu, Hualong; Tang, Yi

    2012-06-11

    A novel route for anti-deactivation of methanol-to-propylene catalyst has been established through supporting nano-gold on ZSM-5, which efficiently reinforces the catalytic stability due to the effect of gold nanoparticles on the stabilization of dehydrogenation intermediates within the coking process. PMID:22549078

  3. Analyzing security of Authenticated Routing Protocol (ARAN)

    OpenAIRE

    Seema Mehla; Bhawna Gupta; Preeti Nagrath

    2010-01-01

    Ad hoc network allow nodes to communicate beyond their direct wireless transmission range by introducing cooperation in mobile computer (nodes). Many proposed routing protocol for ad hoc network operate in an ad hoc fashion, as on demand routing protocol often have low overhead and faster reaction time than other type of routingbased on periodic protocol. However variety of attacks targeting routing protocol have been identified. By attacking the routing protocol attacker can absorb network t...

  4. Aminoacetylation Reaction Catalyzed by Leucyl-tRNA Synthetase Operates via a Self-Assisted Mechanism Using a Conserved Residue and the Aminoacyl Substrate.

    Science.gov (United States)

    Aleksandrov, Alexey; Palencia, Andrés; Cusack, Stephen; Field, Martin

    2016-05-19

    Leucyl-tRNA synthetase catalyzes attachment of leucine amino acid to its cognate tRNA. During the second, aminoacetylation, step of the reaction, the leucyl moiety is transferred from leucyl-adenylate to the terminal A76 adenosine of tRNA. In this work, we have investigated the aminoacetylation step catalyzed by leucyl-tRNA synthase, using ab initio quantum chemical/molecular mechanical hybrid potentials in conjunction with reaction-path-location algorithms and molecular dynamics free energy simulations. We have modeled reaction mechanisms arising from both crystallographic studies and computational work. We invoke various groups as potential proton acceptors-namely, the phosphate and leucyl amino groups of leucyl-adenylate, the A76 base of tRNA, and the Asp80 and Glu532 residues of the protein-and consider both metal-assisted and metal-free reactions. Free energy calculations indicate that both the phosphate group of leucyl adenylate and Glu532 are not strong bases. This agrees with the results of the quantum chemical/molecular mechanical reaction path calculations which give high free energy barriers for the studied pathways involving these groups. A self-assisted mechanism with the leucyl amino group and Asp80 as proton acceptors is the most likely. Furthermore, in this mechanism the presence of a metal ion coordinated by the phosphate group and Glu532 strongly activates the reaction. PMID:27115861

  5. Comparative study on upconversion luminescence and temperature sensing of α- and β-NaYF{sub 4}:Yb{sup 3+}/Er{sup 3+} nano-/micro-crystals derived from a microwave-assisted hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Lili [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Li, Xiangping, E-mail: lixp@dlmu.edu.cn [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Hua, Ruinian [College of Life Science, Dalian Nationalities University, Dalian 116600 (China); Li, Xuejing; Zheng, Hui; Sun, Jiashi; Zhang, Jinsu; Cheng, Lihong [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Chen, Baojiu, E-mail: chenmbj@sohu.com [Department of Physics, Dalian Maritime University, Dalian 116026 (China)

    2015-11-15

    Yb{sup 3+}/Er{sup 3+} co-doped α- and β-phase NaYF{sub 4} nano-/micro-crystals were prepared through a microwave-assisted hydrothermal route. The crystal structure and microscopic morphology of the samples were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Frequency upconverted emissions from the two thermally coupled excited state {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} levels of Er{sup 3+} in both phases of phosphors were recorded at temperatures ranging from room temperature to 573 K under 980 nm infrared laser excitation. The time scanning upconversion spectra were investigated in detail to reveal the thermal effect induced by laser irradiation and the luminescent thermal stability of the two phases NaYF{sub 4} polycrystals. Comparison of the upconversion luminescence and the sensitivity between the two phases NaYF{sub 4} polycrystals indicated that β-phase NaYF{sub 4} won much stronger luminescent intensity, better luminescent thermal stability, and higher temperature sensitivity. - Highlights: • Yb{sup 3+}/Er{sup 3+} codoped NaYF{sub 4} were prepared by a microwave-assisted hydrothermal route. • The UC luminescence and temperature sensing properties were studied. • Comparison of the UCL and the sensitivity between α- and β-phase samples were done. • Thermal effect and UCL thermo-stability were studied by time scanning UCL spectra. • β-phase sample won much better luminescent and temperature sensing properties.

  6. Heritage Route

    Czech Academy of Sciences Publication Activity Database

    Chlustiková, Katarína; Válová, Katarína

    2013. [Kulturstraßen als Konzept. 20 Jahre Straße der Romanik. 14.11.2013-16.11.2013, Merseburg] Grant ostatní: Culture Programme of European Commission(SI) CU7-MULT7/2010-0653/001-001 Source of funding: R - rámcový projekt EK Keywords : cultural routes * Romanesque * heritage Subject RIV: AC - Archeology, Anthropology, Ethnology

  7. A One-Step Microwave-Assisted Synthetic Method for an O/S-Chemoselective Route to Derivatives of the First Adenosine A3 PET Radiotracer

    OpenAIRE

    Karem Shanab; Catharina Neudorfer; Wolfgang Holzer; Markus Mitterhauser; Wolfgang Wadsak; Helmut Spreitzer

    2014-01-01

    The synthesis of reference standards and expected in vivo metabolites of the first adenosine A3 PET radiotracer [18F]FE@SUPPY ([18F]fluoroethyl 4,6-diethyl-5-[(ethyl-sulfanyl)carbonyl]-2-phenylpyridine-3-carboxylate) was achieved by using a straightforward microwave assisted alkylation method, which allowed O/S-chemoselective alkylation of the starting material 1 to give each target compound 2–8 in a single step.

  8. Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

    OpenAIRE

    Weili Wei; Can Xu; Li Wu; Jiasi Wang; Jinsong Ren; Xiaogang Qu

    2014-01-01

    The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicoche...

  9. Peptides quantification by liquid chromatography with matrix-assisted laser desorption/ionization and selected reaction monitoring detection.

    Science.gov (United States)

    Lesur, Antoine; Varesio, Emmanuel; Domon, Bruno; Hopfgartner, Gérard

    2012-10-01

    We present a novel analytical platform for peptides quantitative assays in biological matrices based on microscale liquid chromatography fractionation and matrix-assisted laser desorption/ionization mass spectrometric detection using the selected reaction monitoring (SRM) mode. The MALDI source was equipped with a high frequency Nd:YAG laser (1000 Hz) and mounted on a triple quadrupole/linear ion trap mass spectrometer (MALDI-QqQ(LIT)). Compared to conventional LC-ESI-SRM/MS, the separated analytes are "time-frozen" onto the MALDI plate in fractions, and navigation through the LC chromatogram makes it possible to perform SRM experiments as well as enhanced product ion spectra acquisition for confirmatory analyses without time constraints. The LC spots were analyzed using different rastering speeds ranging from 0.25 to 4 mm/sec with the shortest analysis time of 425 ms/spot. Since the LC runs can be multiplexed and do not need a comprehensive investigation, the present platform offers a valuable alternative to LC-ESI-SRM/MS for high throughput proteomic analyses. In addition, the derivatization of the N-terminal α-amino group by sulfonation was found to be key for the fragmentation of singly charged peptides under low collision energy regime. Under such conditions, y-ion series were observed in the MS/MS spectra, and thus the design of SRM experiments was greatly simplified. The quantitative performance of the platform was compared to that of LC-ESI-SRM/MS by spiking yeast tryptic peptides in human plasma digests. Both platforms exhibited similar sensitivities, accuracy (within ±20%) and precision (under 20%) in the relative quantification mode. As a proof of principle, the relative and absolute quantification of proteins associated with glycolysis, glyoxylate and tricarboxylic acid (TCA) cycles over a growth time course of Saccharomyces cerevisiae on glucose media was successfully performed using isotopic dilution. PMID:22897511

  10. Lipid-assisted protein transport: A diffusion-reaction model supported by kinetic experiments and molecular dynamics simulations

    Science.gov (United States)

    La Rosa, Carmelo; Scalisi, Silvia; Lolicato, Fabio; Pannuzzo, Martina; Raudino, Antonio

    2016-05-01

    The protein transport inside a cell is a complex phenomenon that goes through several difficult steps. The facilitated transport requires sophisticated machineries involving protein assemblies. In this work, we developed a diffusion-reaction model to simulate co-transport kinetics of proteins and lipids. We assume the following: (a) there is always a small lipid concentration of order of the Critical Micellar Concentration (CMC) in equilibrium with the membrane; (b) the binding of lipids to proteins modulates the hydrophobicity of the complexes and, therefore, their ability to interact and merge with the bilayer; and (c) some lipids leave the bilayer to replenish those bound to proteins. The model leads to a pair of integral equations for the time-evolution of the adsorbed proteins in the lipid bilayer. Relationships between transport kinetics, CMC, and lipid-protein binding constants were found. Under particular conditions, a perturbation analysis suggests the onset of kinks in the protein adsorption kinetics. To validate our model, we performed leakage measurements of vesicles composed by either high or low CMC lipids interacting with Islet Amyloid PolyPeptide (IAPP) and Aβ (1-40) used as sample proteins. Since the lipid-protein complex stoichiometry is not easily accessible, molecular dynamics simulations were performed using monomeric IAPP interacting with an increasing number of phospholipids. Main results are the following: (a) 1:1 lipid-protein complexes generally show a faster insertion rate proportional to the complex hydrophobicity and inversely related to lipid CMC; (b) on increasing the number of bound lipids, the protein insertion rate decreases; and (c) at slow lipids desorption rate, the lipid-assisted proteins transport might exhibit a discontinuous behavior and does non-linearly depend on protein concentration.

  11. Nano-organocatalyst: magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal–Knorr reaction, aza-Michael addition, and pyrazole synthesis

    KAUST Repository

    Polshettiwar, Vivek

    2010-01-01

    Postsynthetic Surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity, and high selectivity of nano-organocatalysts for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis. Their insoluble character Coupled with paramagnetic nature enables easy separation of these nano-catalysts from the reaction mixture using external magnet, which eliminates the requirement of catalyst filtration. Published by Elsevier Ltd.

  12. Degradation of Corn Oil Wastes by Fenton Reaction and Under Mildly Basic Media in the Presence of Oxidants Assisted with Sun Light

    Directory of Open Access Journals (Sweden)

    Josefina V.  Sanchez

    2008-01-01

    Full Text Available The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also under mildly basic media in the presence of oxidants, such as hydrogen peroxide and persulfate, assisted with solar light. The degradation efficiency was obtained by analysis of chemical oxygen demand, carbon dioxide and gas chromatography. Over 90% of both chemical oxygen demand abatement and carbon dioxide recovery was accomplished by Fenton reaction. The presence of oxidants during the photodegradation resulted in high chemical oxygen demand abatement of the oil waste with the disappearance of the majority of the initial fatty acids present in the oil waste before treatment.

  13. Reactions to a Partner-Assisted Emotional Disclosure Intervention: Direct Observation and Self-Report of Patient and Partner Communication

    Science.gov (United States)

    Porter, Laura S.; Baucom, Donald H.; Keefe, Francis J.; Patterson, Emily S.

    2012-01-01

    Partner-assisted emotional disclosure is a couple-based intervention designed to help patients disclose cancer-related concerns to their spouses-partners. We previously found that, compared with an education/support control condition, partner-assisted emotional disclosure led to significant improvements in relationship quality and intimacy for…

  14. Facile One-Step Microwave-Assisted Route towards Ni Nanospheres/Reduced Graphene Oxide Hybrids for Non-Enzymatic Glucose Sensing

    Directory of Open Access Journals (Sweden)

    Mojiao Zhou

    2012-04-01

    Full Text Available In this work, a facile one-step microwave-assisted method for deposition of monodisperse Ni nanospheres on reduced graphene oxide (rGO sheets to form Ni-rGO nanohybrids is discussed. In the presence of hydrazine monohydrate, Ni nanospheres are grown onto rGO sheets using nickel precursor and GO as starting materials in ethylene glycol (EG solution under a low level of microwave irradiation (300 W for 20 min, during which GO is also reduced to rGO. The as-prepared nanohybrids exhibit well-dispersed Ni nanosphere (about 80 nm in diameter loadings and effective reduction of graphene oxide. The resulting Ni-rGO nanohybrids-modified glassy carbon electrode (GCE shows significantly improved electrochemical performance in nonenzymatic amperometric glucose detection. In addition, interference from the oxidation of common interfering species under physiological conditions, such as ascorbic acid (AA and uric acid (UA, is effectively avoided.

  15. Clustering-based routing protocol for mobility assistant WSNs%基于分簇的移动协助无线传感器网络路由协议

    Institute of Scientific and Technical Information of China (English)

    兰恒武; 彭舰; 刘唐

    2015-01-01

    提出了一种基于分簇的移动协助( CMA)无线传感器网络路由协议。在圆形网络中,Sink以恒定速率做圆周运动,网络初始阶段根据应用时延要求和能量消耗确定移动 Sink的运动半径,按照确定的Sink运动轨迹,将网络进行分簇。然后在Sink通信范围内确定一批普通节点作为汇聚点( RP),最后Sink对汇聚节点的缓存数据以及其单跳范围内的簇头进行采集。仿真实验结果表明:与现有的几种路由协议相比,CMA在满足时延要求条件下有效地延长了网络生命周期。%Propose a clustering-based routing protocol for mobility assistant( CMA ) wireless sensor networks ( WSNs ). Moving radius of the mobile sink is determined by application delay requirements and energy consumption in initial phase of networks,and the network is clustered according to certain sink motion trail. Select a number of common nodes as the Rendezvous point( RP)within communication range of sink,finally sink gathers cache data of the RP node as well as clusters head within its one-hop range. Simulation results show that compared with several existing routing protocols,CMA effectively prolongs network lifetime in the condition of meeting delay requirements.

  16. Trans-axillary retro-mammary gland route approach of video-assisted breast surgery can perform breast conserving surgery for cancers even in inner side of the breast

    Institute of Scientific and Technical Information of China (English)

    Koji Yamashita; Kazuo Shimizu

    2008-01-01

    Background The endoscopic surgery for inner-side cancer of the breast is usually performed by periareolar approach,but it often makes deformation or malposition of nipple and areola. The trans-axillary approach is favorable without making any injuries on breast skin. Furthermore, we devised a new approach of retro-mammary route without subcutaneous exfoliation, from axillary skin incision, to preserve skin touch sensation.Methods We have performed video-assisted breast surgery (VABS) on 200 patients since December 2001. The newly devised trans-axillary retromammary-route approach (TARM) was performed on 12 patients of early breast cancer. After endoscopic sentinel lymph node biopsy, we lengthened the axillary skin incision to 2.5 cm, and dissected retromammary tissue from superficial pectoral fascia onto major pectoral muscle below the tumor. The working space was made by lifting traction sutures through the gland. We cut the gland vertically at free margin 2 cm apart from the tumor edge, and dissect skin flap over the tumor. The breast reconstruction was done by filling absorbable fiber cotton.Results Traction sutures made it easier to cut the mammary gland vertically. We did not experience any skin damages like bum. All surgical margins were negative. The operation time was needed longer but the blood loss was not different.The postoperative esthetic results were good. The sensory disturbance was minimal. All patients were satisfied with this operation.Conclusion This newly devised TARM approach need no injury on whole breast, and can become a single standard method for breast conserving surgery wherever the cancer situated.

  17. Growth of Co-doped ZnO nanoparticles by porous alumina assisted sol–gel route: Structural optical and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Karak, Nantu [Department of Physics, Visva-Bharati University, Santiniketan 731235, West Bengal (India); Pal, Bappaditya; Sarkar, D. [Department of Physics, Gauhati University, Guwahati 781014, Assam (India); Kundu, Tapas Kumar, E-mail: tapaskumar.kundu@visva-bharati.ac.in [Department of Physics, Visva-Bharati University, Santiniketan 731235, West Bengal (India)

    2015-10-25

    We report a simple sol–gel method with spin coating to grow Co-doped ZnO nanoparticles (NPs) using porous alumina template. X-ray diffraction analysis confirms the wurtzite hexagonal structure for the Zn{sub 1−x}Co{sub x}O NPs. Transmission electron microscopy (TEM) micrograph reveals clearly the formation of NPs with average diameter in the range 40–50 nm. High resolution TEM lattice images and the electron diffraction (SAED) pattern show that the NPs are single crystalline with lattice plane spacing of 2.47 Å for the (101) plane. UV–Vis absorption spectra show a slight blue shift in the absorption edge due to doping related modification in the band structure. PL spectra show a band edge related UV emission around 378 nm at low temperature, while defect (Zn{sub i}, O{sub V}) related visible emission dominates at room temperature. Room temperature ferromagnetism (RTFM) is observed in Zn{sub 1−x}Co{sub x}O NPs with the moment of 450–750 memu/g. The temperature dependent magnetization (M-T) curve shows high transition temperature (T{sub c}) as 750 K. The observed FM is explained using a bound magnetic polaron model and expected to arise from the intrinsic exchange interaction of Co ions and Zn{sub i}, O{sub V} related defects. This study provides an effective way to obtain HTFM with lower doping concentration as well as to have control over NP size by alumina pores in the Zn{sub 1−x}Co{sub x}O system. - Highlights: • Zn{sub 1−x}Co{sub x}O NPs of controlled sizes are grown by Sol-gel route using porus templates. • High density point defects (Zn{sub i}, O{sub V}) are observed in the RT PL spectra. • High temperature FM is observed in the Zn{sub 1−x}Co{sub x}O NPs for low doping concentration. • The observed FM is quantitatively analysed and explained using a BMP model. • FM arises from the intrinsic exchange interaction of Co ions and O{sub V}, Zn{sub i} defects.

  18. Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

    Science.gov (United States)

    Wei, Weili; Xu, Can; Wu, Li; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

  19. Arylation of β,γ-unsaturated lactones by a Heck-Matsuda reaction: an unexpected route to aryldiazene butenolides and pyridazinones

    Directory of Open Access Journals (Sweden)

    Jason G. Taylor

    2010-01-01

    Full Text Available The palladium catalysed coupling of aryldiazonium salts with β-γ-unsaturated lactones under basic conditions has been investigated. Both (3H-furanone and α-angelicalactone were evaluated as substrates in the Heck Matsuda reaction but both failed to afford the desired arylated butenolides. Under basic conditions, β-γ-unsaturated lactones generate highly nucleophilic enolates that preferentially undergo azo coupling reactions with arenediazonium salts to afford aryldiazene butenolides. The electronic and steric effect of the substituents on the aryldiazonium salt in the azo coupling reaction is described. Aryldiazene-lactone derivatives were obtained in good yields from a highly facile and straightforward procedure. An aminoisomaleimide was formed from (3H-furanone and cyclised to the corresponding pyridazinones in modest yield.

  20. Low temperature synthesis of N-doped TiO2 with rice-like morphology through peroxo assisted hydrothermal route: Materials characterization and photocatalytic properties

    Science.gov (United States)

    Bakar, Shahzad Abu; Ribeiro, Caue

    2016-07-01

    Nanorice-shaped N:TiO2 photocatalysts have been prepared by the peroxo assisted hydrothermal method using stabilized titanium complex as a precursor and urea as a N source. The N:TiO2 nanorices were characterised by XRD, FE-SEM, HRTEM, XPS, UV-vis spectroscopy, Raman spectroscopy and measurements of photocatalytic degradation of organic molecules (atrazine and RhB dye) under the UV and visible-light irradiation. XRD analyses showed that pristine TiO2 crystallizes into anatase polymorph and that the N-doping process at 5% introduced a degree of disorder on the TiO2 crystalline structure. XPS study revealed the successful incorporation of the nitrogen atoms at the interstitial sites of the TiO2 crystal lattice. Microscopy studies revealed that the particle size was in the range 50-80 nm for the pristine TiO2. The photocatalysts were assembled in the form of nanorices with a high surface area (102 m2 g-1). The successful incorporation of nitrogen atoms into the TiO2 crystal lattice is expected to be responsible for enhanced photocatalytic activity of the as-prepared samples for the degradation of pollutants (RhB and atrazine) under UV and visible light irradiation. The rate of rad OH radicals formation under visible-light irradiation was examined and found to be correlated with the photocatalytic activity per unit surface area. The N:TiO2 particles with nanorice morphology was efficient photocatalysts for decomposition of organic dyes under UV and visible-light exposure while pristine TiO2 photocatalyst did not show any significant photocatalytic activity when stimulated by visible-light. The 3% doped N:TiO2 sample exhibited the highest photocatalytic activity among all synthesized photocatalysts.

  1. Folic acid bio-inspired route for facile synthesis of AuPt nanodendrites as enhanced electrocatalysts for methanol and ethanol oxidation reactions

    Science.gov (United States)

    Wang, Ai-Jun; Ju, Ke-Jian; Zhang, Qian-Li; Song, Pei; Wei, Jie; Feng, Jiu-Ju

    2016-09-01

    Folic acid (FA), as an important biomolecule in cell division and growth, is firstly employed as the structure director and stabilizing agent for controlled synthesis of uniform Au65Pt35 nanodendrites (NDs) by a one-pot wet-chemical bio-inspired route at room temperature. No pre-seed, template, organic solvent, polymer, surfactant or complex instrument is involved. The products are mainly characterized by transmission electron microscopy (TEM), high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), and X-Ray photoelectron spectroscopy (XPS). The architectures have enlarged electrochemically active surface area (60.6 m2 gPt-1), enhanced catalytic activity and durability for methanol and ethanol oxidation in contrast with commercial Pt black and the other AuPt alloys by tuning the molar ratios of Au to Pt (e.g., Au31Pt69 and Au82Pt18 nanoparticles). This strategy would be applied to fabricate other bimetallic nanocatalysts in fuel cells.

  2. Asymmetric NHC-catalyzed aza-Diels-Alder reactions: Highly enantioselective route to α-amino acid derivatives and DFT calculations

    KAUST Repository

    Yang, Limin

    2014-08-01

    A facile N-heterocyclic carbene catalytic enantioselective aza-Diels-Alder reaction of oxodiazenes with α-chloroaldehydes as dienophile precursors is reported, with excellent enantioselectivity (ee > 99%) and excellent yield (up to 93%). DFT study showed that cis-TSa, formed from a top face approach of oxodiazene to cis-IIa, is the most favorable transition state and is consistent with the experimental observations. © 2014 American Chemical Society.

  3. Thiocyanation of closo-Dodecaborate B12H12 2-. A Novel Synthetic Route and Theoretical Elucidation of the Reaction Mechanism

    Czech Academy of Sciences Publication Activity Database

    Lepšík, Martin; Srnec, Martin; Plešek, Jaromír; Buděšínský, Miloš; Klepetářová, Blanka; Hnyk, Drahomír; Grüner, Bohumír; Rulíšek, Lubomír

    2010-01-01

    Roč. 49, č. 11 (2010), s. 5040-5048. ISSN 0020-1669 R&D Projects: GA MŠk LC512; GA MŠk LC523; GA AV ČR IAAX00320901 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40320502 Keywords : thiocyanation * closo-dodecaborate * reaction mechanism * theoretical calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.326, year: 2010

  4. 2DCOR-GC: an application of the generalized two-dimensional correlation analysis as a route to optimization of continuous flow supercritical fluid reactions.

    Science.gov (United States)

    Hyde, Jason R; Bourne, Richard A; Noda, Isao; Stephenson, Phil; Poliakoff, Martyn

    2004-11-01

    A new approach for optimization and monitoring of continuous reactions has been developed using 2D correlation methods for the analysis of GC data (2DCOR-GC). 2DCOR-GC maps are obtained following perturbation of the system that allow the effect of changing reaction parameters such as time, temperature, pressure, or concentration to be both monitored and sequenced with regard to changes in the raw GC data. In this paper, we describe the application of the 2DCOR-GC technique to monitoring the reverse water-gas shift reaction in scCO(2). 2DCOR-GC is combined with FT-IR data to validate the methodology. We also report the application of 2DCOR-GC to probe the mechanism of the alkylation of m-cresol with isopropyl alcohol in scCO(2) using Nafion SAC-13 as the catalyst. These results identify coeluting peaks that could easily be missed without exhaustive method development. PMID:15516110

  5. An efficient route for catalytic activity promotion via hybrid electro-depositional modification on commercial nickel foam for hydrogen evolution reaction in alkaline water electrolysis

    International Nuclear Information System (INIS)

    Highlights: • Mono-Cu surface modification depress the HER activity of Ni-foam. • Hybrid Ni-foam/Cu0.01/Co0.05 exhibits superior HER performance. • Layer-by-layer structure may contribute to a synergistic promoting effect. - Abstract: In this paper, the single- and hybrid-layered Cu, Ni and Co thin films were electrochemically deposited onto the three-dimensional nickel foam as composite cathode catalyst for hydrogen evolution reaction in alkaline water electrolysis. The morphology, structure and chemical composition of the electrodeposited composite catalysts were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Electrochemical measurement depicted that, for the case of the monometallic layered samples, the general activity for hydrogen evolution reaction followed the sequence: Ni-foam/Ni > Ni-foam/Co > bare Ni-foam > Ni-foam/Cu. It is noteworthy that, the hybrid-layered Ni-foam/Cu0.01/Co0.05 exhibited the highest catalytic activity towards hydrogen evolution reaction with the current density as high as 2.82 times that of the bare Ni-foam. Moreover, both excellent electrochemical and physical stabilities can also be acquired on the Ni-foam/Cu0.01/Co0.05, making this hybrid-layered composite structure as a promising HER electro-catalyst

  6. A novel microwave route for the preparation of ZrC-SiC composites

    Science.gov (United States)

    Das, Bharat. P.; Panneerselvam, M.; Rao, K. J.

    2003-06-01

    A novel microwave-assisted carbothermal reduction and carburization route has been used to prepare ZrC-SiC composite powders. Both zircon and mixtures of ZrO 2 and SiO 2 were used as starting materials along with amorphous carbon. Carbothermal reduction and carburization were examined in both argon and nitrogen atmospheres. Reaction kinetics in microwave field was found to exhibit notable differences for the two different starting materials. However, a complete oxide to carbide conversion was achieved in less than 30 min in both cases when argon was used as an ambient gas. The possible structural mechanism involved in the reactions has been discussed.

  7. A novel microwave route for the preparation of ZrC-SiC composites

    International Nuclear Information System (INIS)

    A novel microwave-assisted carbothermal reduction and carburization route has been used to prepare ZrC-SiC composite powders. Both zircon and mixtures of ZrO2 and SiO2 were used as starting materials along with amorphous carbon. Carbothermal reduction and carburization were examined in both argon and nitrogen atmospheres. Reaction kinetics in microwave field was found to exhibit notable differences for the two different starting materials. However, a complete oxide to carbide conversion was achieved in less than 30 min in both cases when argon was used as an ambient gas. The possible structural mechanism involved in the reactions has been discussed

  8. Mobility Tolerant Firework Routing for Improving Reachability in MANETs

    OpenAIRE

    Gen Motoyoshi; Kenji Leibnitz; Masayuki Murata

    2014-01-01

    In this paper, we investigate our mobility-assisted and adaptive broadcast routing mechanism, called Mobility Tolerant Firework Routing (MTFR), which utilizes the concept of potentials for routing and improves node reachability, especially in situations with high mobility, by including a broadcast mechanism. We perform detailed evaluations by simulations in a mobile environment and demonstrate the advantages of MTFR over conventional potential-based routing. In particular, we show that MTFR p...

  9. A Novel One-Pot and One-Step Microwave-Assisted Cyclization-Methylation Reaction of Amino Alcohols and Acetylated Derivatives with Dimethyl Carbonate and TBAC

    Directory of Open Access Journals (Sweden)

    Adrián Ochoa-Terán

    2014-01-01

    Full Text Available A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction.

  10. A novel one-pot and one-step microwave-assisted cyclization-methylation reaction of amino alcohols and acetylated derivatives with dimethyl carbonate and TBAC.

    Science.gov (United States)

    Ochoa-Terán, Adrián; Guerrero, Leticia; Rivero, Ignacio A

    2014-01-01

    A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction. PMID:25692177

  11. Direct Energy Supply to the Reaction Mixture during Microwave-Assisted Hydrothermal and Combustion Synthesis of Inorganic Materials

    Directory of Open Access Journals (Sweden)

    Roberto Rosa

    2014-05-01

    Full Text Available The use of microwaves to perform inorganic synthesis allows the direct transfer of electromagnetic energy inside the reaction mixture, independently of the temperature manifested therein. The conversion of microwave (MW radiation into heat is useful in overcoming the activation energy barriers associated with chemical transformations, but the use of microwaves can be further extended to higher temperatures, thus creating unusual high-energy environments. In devising synthetic methodologies to engineered nanomaterials, hydrothermal synthesis and solution combustion synthesis can be used as reference systems to illustrate effects related to microwave irradiation. In the first case, energy is transferred to the entire reaction volume, causing a homogeneous temperature rise within a closed vessel in a few minutes, hence assuring uniform crystal growth at the nanometer scale. In the second case, strong exothermic combustion syntheses can benefit from the application of microwaves to convey energy to the reaction not only during the ignition step, but also while it is occurring and even after its completion. In both approaches, however, the direct interaction of microwaves with the reaction mixture can lead to practically gradient-less heating profiles, on the basis of which the main observed characteristics and properties of the aforementioned reactions and products can be explained.

  12. Microwave-assisted reactions: Three-component process for the synthesis of 2-amino-2-chromenes under microwave heating

    Institute of Scientific and Technical Information of China (English)

    Ramadan A. Mekheimer; Kamal U. Sadek

    2009-01-01

    2-Amino-2-chromenes are class of heterocycles that posses considerable interest as pigments, cosmetics, potential agro-chemicals and being the main constituents of many natural products. Although, they are generally prepared either under conventional heating, benign reagents or very recently, a three component condensation in poly-ethylene glycol-water in the presence of nanosized magnesium oxide, most of these methods require prolonged reaction time, reagents in stoichiometric amounts and generate moderate yields of products. Microwave technique performs a better yield in a short reaction time (85-94%;5-8 rain). Also, three-component one step reaction is of great interest for cost savings from the point of raw materials, energy and time. A combination between both techniques will be attractive for researchers in that field.

  13. 8-Membered-ring Transition States of Water Assisted Reactions in Sub-and Super-critical Water

    Institute of Scientific and Technical Information of China (English)

    Kazuya; Kobiro; Pengyu; Wang

    2007-01-01

    1 Results Sub-and super-critical water is an attractive reaction medium for organic transformation because of their unique properties such as low viscosity,high density,low polarity,high solubility to organic compounds,and,of course,the greenness of the medium[1-3]. We report herein some unique reactions of unsaturated compounds in sub-and super-critical water.When allylbenzene was treated in supercritical water (SCW: 380 ℃,10 min,water density=0.35 g/mL),double bond migrated to give a mixture of allylb...

  14. Microwave Assisted Synthesis of Osmium Electrocatalysts for the Oxygen Reduction Reaction in the Absence and Presence of Aqueous Methanol

    Directory of Open Access Journals (Sweden)

    Edgar Borja-Arco

    2011-01-01

    Full Text Available Osmium electrocatalysts for the oxygen reduction reaction (ORR were prepared by microwave irradiation of Os3(CO12 at different experimental conditions. The materials obtained were structurally characterized by FT-IR, micro-Raman spectroscopy and X-ray diffraction. Their chemical compositions were obtained by EDS. The electrocatalytic properties for the oxygen reduction reaction were evaluated by rotating disk electrode measurements in 0.5 mol L-1 H2SO4, in the absence and presence of aqueous methanol. The kinetic parameters, such as Tafel slope, exchange current density, and charge transfer coefficient are reported.

  15. Relevance of the synthesis route of Se-modified Ru/C as methanol tolerant electrocatalysts for the oxygen reduction reaction

    Science.gov (United States)

    Montiel, M.; García-Rodríguez, S.; Hernández-Fernández, P.; Díaz, R.; Rojas, S.; Fierro, J. L. Gª; Fatás, E.; Ocón, P.

    A series of Se-modified Ru/C (Se-Ru/C) samples were prepared from a carbon-supported ruthenium precursor. Selenium was incorporated by two different methods; in the first case, Se was incorporated by treating the Ru/C precursor in a selenious acid solution followed by reduction in H 2 atmosphere. In the second case, Se was incorporated to Ru/C by means of thermal treatment in a selenium atmosphere. The samples thus obtained were characterized by different techniques: X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. A detailed study has been made of the structural properties and chemical composition of the different Se-Ru/C samples. Microscopy results reveal that Se is incorporated homogeneously, being preferentially located on the surface of the Ru atoms. These results agree well with XRD and XPS data. The incorporation of Se in the lattice results in the formation of RuSe 2 only if RuO 2 already exists. On the contrary, if Ru is in its metallic form, Se remains as an amorphous layer located on the surface of the Ru particles. The performance of the catalysts on the oxygen reduction reaction was evaluated either in the absence and presence of methanol. Se-containing samples develop more active and methanol tolerant catalysts, particularly when Se is located on the surface of the Ru particles.

  16. Particle morphology and luminescence properties of green emitting Ba2SiO4:Eu2+ through a hydrothermal reaction route

    International Nuclear Information System (INIS)

    Green-emitting (Ba0.97Eu0.03)2SiO4 phosphors of different morphologies and particle sizes were prepared by varying the conditions of hydrothermal synthesis. Single-phase powders were obtained at 250 °C and autogeneous pressure followed by post annealing at 900 °C for 1 h. The ethanol/water ratio, hydrothermal reaction time, NaOH/Ba2+ ratio and silicon precursor strongly influence the particle size and morphology. The particle size, having spherical or needlelike shapes, ranges from 200 nm to 3 μm, depending on those parameters. These phosphors show strong absorption in the near UV range and the photoluminescence emission spectra consist of a strong broad green band centered around 514 nm. Furthermore, the emission intensities are dependent on the ethanol to water ratio, and 55–79% of that of micron-sized powders with a quantum efficiency of 94%. - Highlights: • (Ba0.97Eu0.03)2SiO4 with sub-micron particle sizes were prepared by hydrothermal synthesis. • Post-synthesis annealing at 900 °C results in single phase powders with a spherical morphology. • The emission intensities are 55–79% of micron-sized powders that have a quantum efficiency of 94%

  17. Particle morphology and luminescence properties of green emitting Ba{sub 2}SiO{sub 4}:Eu{sup 2+} through a hydrothermal reaction route

    Energy Technology Data Exchange (ETDEWEB)

    Han, J.K. [Condensed Matter Physics and Materials Sciences Department, Building 480, Brookhaven National Laboratory, Upton, NY 11973 (United States); Hannah, M.E.; Piquette, A. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Dr. Beverly, MA 01915 (United States); Talbot, J.B. [University of California, San Diego, Dept. of Nanoengineering, La Jolla, CA 92093 (United States); Mishra, K.C. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Dr. Beverly, MA 01915 (United States); McKittrick, J., E-mail: jmckittrick@ucsd.edu [University of California, San Diego, Dept. of Mechanical and Aerospace Engineering, La Jolla, CA 92093 (United States)

    2015-05-15

    Green-emitting (Ba{sub 0.97}Eu{sub 0.03}){sub 2}SiO{sub 4} phosphors of different morphologies and particle sizes were prepared by varying the conditions of hydrothermal synthesis. Single-phase powders were obtained at 250 °C and autogeneous pressure followed by post annealing at 900 °C for 1 h. The ethanol/water ratio, hydrothermal reaction time, NaOH/Ba{sup 2+} ratio and silicon precursor strongly influence the particle size and morphology. The particle size, having spherical or needlelike shapes, ranges from 200 nm to 3 μm, depending on those parameters. These phosphors show strong absorption in the near UV range and the photoluminescence emission spectra consist of a strong broad green band centered around 514 nm. Furthermore, the emission intensities are dependent on the ethanol to water ratio, and 55–79% of that of micron-sized powders with a quantum efficiency of 94%. - Highlights: • (Ba{sub 0.97}Eu{sub 0.03}){sub 2}SiO{sub 4} with sub-micron particle sizes were prepared by hydrothermal synthesis. • Post-synthesis annealing at 900 °C results in single phase powders with a spherical morphology. • The emission intensities are 55–79% of micron-sized powders that have a quantum efficiency of 94%.

  18. A NEW ROUTE TO DIRECT CATALYTIC SYNTHESIS OF ACETIC ACID FROM METHANE BY A LOW-TEMPERATURE REACTION%甲烷低温催化直接合成乙酸的新途径

    Institute of Scientific and Technical Information of China (English)

    丁一慧; 黄伟; 晋萍; 谢克昌

    2001-01-01

    The selective conversion of methane to more useful target products such as acetic acid would be far more attractive. The classical utilization and recent research for methane conversion to acetic acid by both the indirect route involved multi-step process through syngas stage and the direct one avoided syngas production were reviewed in this paper. Technology comparison and results analysis of the indirect route with the direct one, and of homogeneous catalyst systems with heterogeneous ones employed in oxidative carbonylation or carboxylation of methane to synthesize acetic acid directly led to such a suggestion as follows. That is, an environmentally benign route to direct synthesis of acetic acid from inexpensive feedstocks methane and carbon dioxide, in particular, using solid, heterogeneous catalysts at low temperature has its remarkable significance in view of energy, environment and economy. The further research will enrich the theory and practice of green C1 chemistry and performance of thermodynamically unfavo-rable reactions.%对甲烷经合成气路线间接制乙酸的现状及在温和条件下直接转化制乙酸的研究进展作了述评.通过对间接与直接路线的比较,以及在直接路线中,甲烷低温氧化羰化和直接羧化制乙酸均相与非均相催化体系的分析,指出了CH4-CO2低温直接合成乙酸在工艺过程上的显著优势,尤其是采用非均相催化体系.该工艺为乙酸合成和CH4与CO2的绿色化学利用开辟了新途径,其研究将会丰富C1化学化工的理论与实践,并为实现热力学不利反应提供实验方法和理论依据.

  19. A highly efficient group-assisted purification method for the synthesis of poly-functionalized pyrimidin-5-yl-pyrroles via one-pot four-component domino reaction.

    Science.gov (United States)

    Dommaraju, Yuvaraj; Prajapati, Dipak

    2015-02-01

    A highly efficient, catalyst-free group-assisted purification chemical protocol for the construction of pyrimidine containing poly-functionalized pyrroles from a four-component domino reaction of acyclic-1,3-dicarbonyls or electron deficient alkynes, aromatic amines, barbituric acid and arylglyoxal hydrates under mild reaction conditions has been developed. The prominent features of the present protocol are environmentally benign, mild reaction conditions, atom economy, no column chromatography separation, easy isolation of products and excellent yields. PMID:25173493

  20. Nafion®-catalyzed microwave-assisted Ritter reaction: An atom-economic solvent-free synthesis of amides

    Science.gov (United States)

    An atom-economic solvent-free synthesis of amides by the Ritter reaction of alcohols and nitriles under microwave irradiation is reported. This green protocol is catalyzed by solid supported Nafion®NR50 with improved efficiency and reduced waste production.

  1. Route to Renewable PET: Reaction Pathways and Energetics of Diels–Alder and Dehydrative Aromatization Reactions Between Ethylene and Biomass-Derived Furans Catalyzed by Lewis Acid Molecular Sieves

    OpenAIRE

    Pacheco, Joshua J.; Labinger, Jay A.; Alex L Sessions; Davis, Mark E.

    2015-01-01

    Silica molecular sieves that have the zeolite beta topology and contain framework Lewis acid centers (e.g., Zr-β, Sn-β) are useful catalysts in the Diels–Alder and dehydrative aromatization reactions between ethylene and various renewable furans for the production of biobased terephthalic acid precursors. Here, the main side products in the synthesis of methyl 4-(methoxymethyl)benzene carboxylate that are obtained by reacting ethylene with methyl 5-(methoxymethyl)-furan-2-carboxylate are iden...

  2. Routing Proposals for Multipath Interdomain Routing

    OpenAIRE

    Bilal, Sardar M.; Dilber, Muhammad Naveed; Khan, Atta ur Rehman

    2013-01-01

    Internet is composed of numbers of independent autonomous systems. BGP is used to disseminate reachability information and establishing path between autonomous systems. Each autonomous system is allowed to select a single route to a destination and then export the selected route to its neighbors. The selection of single best route imposes restrictions on the use of alternative paths during interdomain link failure and thus, incurred packet loss. Packet loss still occurs even when multiple pat...

  3. Investigation of photo-assisted and crude peroxidase mediated transformations of chlorinated phenols (CPs) from spiked and industrial wastewaters: identification of reaction products.

    Science.gov (United States)

    Sharma, Swati; Mukhopadhyay, Mausumi; Murthy, Z V P

    2015-01-01

    This work focused on photo-assisted crude peroxidase mediated transformations of chlorinated phenols (CPs) from spiked and industrial wastewaters and the identification of reaction products formed. Garden radish Raphanus sativus was the source of crude peroxidase. No chlorine bearing compounds were detected by gas chromatography-high resolution mass spectrometry analysis. Under identical test conditions, the concentrations of 4-chlorophenol and 2,4-dichlorophenol were demoted to zero from 514 mg/L, 652 mg/L and that of 2,4,6-trichlorophenol and pentachlorophenol were reduced to 18 mg/L and 37 mg/L from 790 mg/L and 1066 mg/L, respectively (high-pressure liquid chromatography analysis). Chloride ion release profiles also showed a progressively increasing trend. A neat chemical oxygen demand removal to the extent of 63-79% was achieved in the case of spiked wastewater sample and to the extent of 77% for industrial wastewaters. A hypothesis reaction scheme was also suggested to comprehend the mechanism of degradation reactions. PMID:26287833

  4. Rapid grafting of azido-labeled oligo(ethylene glycol)s onto an alkynyl-terminated monolayer on nonoxidized silicon via microwave-assisted "click" reaction.

    Science.gov (United States)

    Li, Yan; Wang, Jun; Cai, Chengzhi

    2011-03-15

    Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated nonoxidized silicon substrates via copper-catalyzed "click" reaction. The "clickable" monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data obtained were utilized to calculate the surface density of the TMG-alkynyl-functionalized substrate. MW-assisted one-pot deprotection/click reaction was optimized on the surfaces using azido-tagged OEG derivatives. Using MW instead of conventional heating led to a substantial improvement in the rate of the reaction while suppressing the oxidation of the silicon interface and OEG degradation. The antifouling property of the resulting substrates was evaluated using fibrinogen as a model protein. Results show that the OEG-modification reduced the protein adsorption by >90%. PMID:21306165

  5. Oxygen assisted reconstructions of rhodium and platinum nanocrystals and their effects on local catalytic activity of hydrogenation reactions

    Science.gov (United States)

    Barroo, C.; Gilis, N.; Lambeets, S. V.; Devred, F.; Visart de Bocarmé, T.

    2014-06-01

    The reconstruction of rhodium and platinum crystals of some tens of nanometres diameter was investigated during the ongoing hydrogenation of oxygen atoms resulting from the dissociation of O2 and NO2 species. Field ion and field emission electron microscopies (FIM and FEM) were used to characterise the apex of tip samples before, during and after the catalytic reactions. On rhodium samples, the exposure of less than 10 Langmuir of O2 is sufficient to induce significant morphological changes. At higher exposures, the presence of subsurface oxygen causes surface reconstructions illustrated with atomic resolution by FIM at 50 K. The same pattern is also visible at 505 K in the presence of H2 and O2 during water production. Upon the decrease of H2 pressure, surface oxidation shows a strong sensitivity to the local surface initiated along the zone lines. On platinum, the kinetic instabilities of the NO2-H2 reaction are followed by FEM at 390 K starting from a hemispherical tip sample. The instabilities are expressed as surface explosions occurring randomly in time, but synchronised over {0 1 1} facets. These instabilities expand along the lines over the (0 0 1) pole and exhibit self-sustained kinetic oscillations. The analysis of the tips by FIM after the reaction shows dark regions over the {1 1 3} facets, suggesting the extension of those to the detriment of vicinal ones. A well-controlled field evaporation procedure reveals that these regions appear dark due to the presence of surface oxygen. Structural reconstructions are observed but do not lead to the drastic morphological changes suggested by the FIM and FEM patterns. Nanoparticle dynamics must be accounted in models describing the non-linear features of catalytic reactions and more generally included in the description of catalytic properties of nanosized particles.

  6. Oxygen assisted reconstructions of rhodium and platinum nanocrystals and their effects on local catalytic activity of hydrogenation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Barroo, C.; Gilis, N.; Lambeets, S.V.; Devred, F.; Visart de Bocarmé, T., E-mail: tvisart@ulb.ac.be

    2014-06-01

    The reconstruction of rhodium and platinum crystals of some tens of nanometres diameter was investigated during the ongoing hydrogenation of oxygen atoms resulting from the dissociation of O{sub 2} and NO{sub 2} species. Field ion and field emission electron microscopies (FIM and FEM) were used to characterise the apex of tip samples before, during and after the catalytic reactions. On rhodium samples, the exposure of less than 10 Langmuir of O{sub 2} is sufficient to induce significant morphological changes. At higher exposures, the presence of subsurface oxygen causes surface reconstructions illustrated with atomic resolution by FIM at 50 K. The same pattern is also visible at 505 K in the presence of H{sub 2} and O{sub 2} during water production. Upon the decrease of H{sub 2} pressure, surface oxidation shows a strong sensitivity to the local surface initiated along the 〈0 0 1〉 zone lines. On platinum, the kinetic instabilities of the NO{sub 2}–H{sub 2} reaction are followed by FEM at 390 K starting from a hemispherical tip sample. The instabilities are expressed as surface explosions occurring randomly in time, but synchronised over {0 1 1} facets. These instabilities expand along the 〈0 0 1〉 lines over the (0 0 1) pole and exhibit self-sustained kinetic oscillations. The analysis of the tips by FIM after the reaction shows dark regions over the {1 1 3} facets, suggesting the extension of those to the detriment of vicinal ones. A well-controlled field evaporation procedure reveals that these regions appear dark due to the presence of surface oxygen. Structural reconstructions are observed but do not lead to the drastic morphological changes suggested by the FIM and FEM patterns. Nanoparticle dynamics must be accounted in models describing the non-linear features of catalytic reactions and more generally included in the description of catalytic properties of nanosized particles.

  7. Routing in opportunistic networks

    CERN Document Server

    Dhurandher, Sanjay; Anpalagan, Alagan; Vasilakos, Athanasios

    2013-01-01

    This book provides a comprehensive guide to selected topics, both ongoing and emerging, in routing in OppNets. The book is edited by worldwide technical leaders, prolific researchers and outstanding academics, Dr. Isaac Woungang and co-editors, Dr. Sanjay Kumar Dhurandher, Prof. Alagan Anpalagan and Prof. Athanasios Vasilakos. Consisting of contributions from well known and high profile researchers and scientists in their respective specialties, the main topics that are covered in this book include mobility and routing, social-aware routing, context-based routing, energy-aware routing, incentive-aware routing, stochastic routing, modeling of intermittent connectivity, in both infrastructure and infrastructure-less OppNets. Key Features: Discusses existing and emerging techniques for routing in infrastructure and infrastructure-less OppNets. Provides a unified covering of otherwise disperse selected topics on routing in infrastructure and infrastructure-less OppNets.  Includes a set of PowerPoint slides and g...

  8. Kinetic and mechanistic studies of reactive intermediates in photochemical and transition metal-assisted oxidation, decarboxylation and alkyl transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Carraher, Jack McCaslin [Iowa State Univ., Ames, IA (United States)

    2014-01-01

    Reactive species like high-valent metal-oxo complexes and carbon and oxygen centered radicals are important intermediates in enzymatic systems, atmospheric chemistry, and industrial processes. Understanding the pathways by which these intermediates form, their relative reactivity, and their fate after reactions is of the utmost importance. Herein are described the mechanistic detail for the generation of several reactive intermediates, synthesis of precursors, characterization of precursors, and methods to direct the chemistry to more desirable outcomes yielding ‘greener’ sources of commodity chemicals and fuels.

  9. Microwave-assisted heterogeneous cross-coupling reactions catalyzed by nickel-in-charcoal (Ni/C).

    Science.gov (United States)

    Lipshutz, Bruce H; Frieman, Bryan A; Lee, Ching-Tien; Lower, Asher; Nihan, Danielle M; Taft, Benjamin R

    2006-09-18

    A study involving the relatively rare combination of heterogeneous catalysis conducted under microwave conditions is presented. Carbon-carbon bond formation, including Negishi and Suzuki couplings, can be quickly effected with aryl chloride partners by using a base metal (nickel) adsorbed in the pores of activated charcoal. Aminations were also studied, along with cross-couplings of vinyl alanes with benzylic chlorides as a means to stereodefined allylated aromatics. Reaction times for all these processes are typically reduced from several hours to minutes in a microwave reactor. PMID:17441078

  10. Digital Labeling and Narrative Mapping in Mobile Remote Audio Signage: Verbalization of Routes and Generation of New Verbal Route Descriptions from Existing Route Sets

    OpenAIRE

    Tammineni, Tharun Tej

    2013-01-01

    Independent navigation is a great challenge for people with visual impairments. In this project, we have designed and implemented an assisted navigation solution based on the ability of visually impaired travelers to interpret and contextualize verbal route descriptions. Previous studies have validated that if a route is verbally described in sufficient and appropriate manner then VI can use their orientation and mobility skills to successfully follow the route. In this project, we do not con...

  11. Supramolecular gel-assisted synthesis of double shelled Co@CoO@N-C/C nanoparticles with synergistic electrocatalytic activity for the oxygen reduction reaction

    Science.gov (United States)

    Wu, Zexing; Wang, Jie; Han, Lili; Lin, Ruoqian; Liu, Hongfang; Xin, Huolin L.; Wang, Deli

    2016-02-01

    Investigating active, stable, and low-cost materials for the oxygen reduction reaction is one of the key challenges in fuel-cell research. In this work, we describe the formation of N-doped carbon shell coated Co@CoO nanoparticles supported on Vulcan XC-72 carbon materials (Co@CoO@N-C/C) based on a simple supramolecular gel-assisted method. The double-shelled Co@CoO@N-C/C core-shell nanoparticles exhibit superior electrocatalytic activities for the oxygen reduction reaction compared to N-doped carbon and cobalt oxides, demonstrating the synergistic effect of the hybrid nanomaterials. Notably, the Co@CoO@N-C/C nanoparticles give rise to a comparable four-electron selectivity, long-term stability, and high methanol tolerance; all show a multi-fold improvement over the commercial Pt/C catalyst. The progress is of great importance in exploring advanced non-precious metal-based electrocatalysts for fuel cell applications.Investigating active, stable, and low-cost materials for the oxygen reduction reaction is one of the key challenges in fuel-cell research. In this work, we describe the formation of N-doped carbon shell coated Co@CoO nanoparticles supported on Vulcan XC-72 carbon materials (Co@CoO@N-C/C) based on a simple supramolecular gel-assisted method. The double-shelled Co@CoO@N-C/C core-shell nanoparticles exhibit superior electrocatalytic activities for the oxygen reduction reaction compared to N-doped carbon and cobalt oxides, demonstrating the synergistic effect of the hybrid nanomaterials. Notably, the Co@CoO@N-C/C nanoparticles give rise to a comparable four-electron selectivity, long-term stability, and high methanol tolerance; all show a multi-fold improvement over the commercial Pt/C catalyst. The progress is of great importance in exploring advanced non-precious metal-based electrocatalysts for fuel cell applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07929b

  12. Photocatalytic Properties of Silver Core/Titania Shell Nano-Wires Grown on a Glass Substrate Using a Glycothermal Process Assisted by a Photochemical Reaction.

    Science.gov (United States)

    Song, Duck-Hyun; Hirato, Tetsuji

    2015-07-01

    A silver core/titania shell nano-wire film was successfully prepared on a glass substrate via a glycothermal process that was assisted by a photochemical reaction using tetra-n-butyl titanate as the titanium source and silver nitrate as the silver source in an autoclave with ethylene glycol as a solvent. The morphology, diameter, length, and density of the core/shell nano-wires that were synthesized could be varied by changing the silver/titanium molar ratio of the starting materials. The samples produced were characterized by X-ray diffraction and scanning electron microscopy. The photocatalytic activity of the silver core/titania shell nano-wire film was investigated by measuring the photodegradation rate of rhodamine B in aqueous solution. PMID:26373082

  13. Mobility Tolerant Firework Routing for Improving Reachability in MANETs

    Directory of Open Access Journals (Sweden)

    Gen Motoyoshi

    2014-03-01

    Full Text Available In this paper, we investigate our mobility-assisted and adaptive broadcast routing mechanism, called Mobility Tolerant Firework Routing (MTFR, which utilizes the concept of potentials for routing and improves node reachability, especially in situations with high mobility, by including a broadcast mechanism. We perform detailed evaluations by simulations in a mobile environment and demonstrate the advantages of MTFR over conventional potential-based routing. In particular, we show that MTFR produces better reachability in many aspects at the expense of a small additional transmission delay and intermediate traffic overhead, making MTFR a promising routing protocol and feasible for future mobile Internet infrastructures.

  14. One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger–aza-Wittig reaction

    Directory of Open Access Journals (Sweden)

    Diego Carnaroglio

    2013-11-01

    Full Text Available A fast and efficient protocol for the synthesis of N,N'-disubstituted urea derivatives from alkyl halides and primary or secondary amines has been developed. The synthetic pathway combines nucleophilic substitutions and a Staudinger–aza-Wittig reaction in the presence of polymer-bound diphenylphosphine under 14 bar of CO2 pressure and has been performed in a one-pot two-step process. The protocol has been optimized under microwave irradiation and the scale-up experiment has been conducted under conventional conditions in a Parr reactor. The final compounds were isolated after simple filtration in almost quantitative overall yields which makes this procedure facile and rapid to execute.

  15. Enhanced photoluminescence of SrWO4:Eu3+ red phosphor synthesized by mechanochemically assisted solid state metathesis reaction method at room temperature

    International Nuclear Information System (INIS)

    Optically efficient europium activated alkaline earth metal tungstate nano phosphor (SrWO4) with different doping concentrations have been synthesized by mechanochemically assisted solid state metathesis reaction at room temperature for the first time. The XRD and Raman spectra results indicated that the prepared powders exhibit a scheelite-type tetragonal structure. FTIR spectra exhibited a high absorption band situated at around 854 cm−1, which was ascribed to the W–O antisymmetric stretching vibrations into the [WO4]2− tetrahedron groups. Analysis of the emission spectra with different Eu3+ concentrations revealed that the optimum dopant concentration for SrWO4: x Eu3+ phosphor is about 8 mol% of Eu3+.The red emission intensity of the SSM prepared SrWO4: 0.08Eu3+ phosphors are 2 times greater than that of the commercial Y2O2S: Eu3+ red phosphor prepared by the conventional solid state reaction method. All the results indicate that the phosphor is a promising red phosphor pumped by NUV InGaN chip for fabricating WLED

  16. Microwave-assisted reaction of peptide formation by amino acid with phosphate: Exploration of the most possible channels for the origin of life

    Institute of Scientific and Technical Information of China (English)

    HU Rong; TIAN Jinping; YIN Yingwu

    2006-01-01

    Microwave-assisted reaction of peptide formation by amino acids with phosphate was studied. The results showed that the products were a mixture of peptides containing dipeptide, octapeptides and cyclic peptides, which could be obtained in a short time. Polyphosphate was also produced synchronously by the intermolecular condensation of phosphate. The polymerization degree reached 99% (pyrophosphate 64%, trimetaphosphate 35%) after 2 h at 200℃ under microwave irradiation. The intermediates of the mixed anhydrides formed by the intermolecular condensation of phosphates and glycin were determined by ESI-MS. Peptides were also produced by the reaction of amino acids with trimetaphosphate in aqueous solution. The conversion degree of valine reached 46.5% even at room temperature. The cyclic process of peptide formation and phosphate polymerization, regeneration and utilization in amino acids-phosphate system under microwave irradiation was detected and proved. Peptides could be continually formed only by inputting energy into this system. The above recycle may be the most possible process for primitive peptide formation in the origin of life.

  17. Routing and scheduling problems

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander

    to a destination on a predefined network, the routing and scheduling of vessels in a liner shipping network given a demand forecast to be covered, the routing of manpower and vehicles transporting disabled passengers in an airport and the vehicle routing with time windows where one version studied includes edge...

  18. Preparation of lithium aluminate via polymeric precursor routes

    International Nuclear Information System (INIS)

    Gamma lithium aluminate is a potential candidate for tritium breeding material. Various preparation routes have been proposed including solid state reaction methods and wet chemical methods such as sol-gel process. But it is still needed to develop reliable and economic preparation methods that can be used for large production. In this paper, we examined three polymeric precursor methods - amorphous citrate process, Pechini process, and polyvinyl alcohol-assisted process - by studying thermal behavior of the precursor powders by X-ray diffractometry, differential thermal analysis, infrared spectrometry, and BET surface area analysis. All these three processes produced phase pure gamma lithium aluminate powders at a relatively low temperature. The phase purity and processing temperature were comparable to the alkoxide derived sol-gel method and yet these polymeric precursor methods did not require high quality starting materials such as alkoxides. (orig.)

  19. State alternative route designations

    Energy Technology Data Exchange (ETDEWEB)

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a ``state routing agency,`` defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  20. State alternative route designations

    Energy Technology Data Exchange (ETDEWEB)

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a state routing agency,'' defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  1. Silver Nanolabels-Assisted Ion-Exchange Reaction with CdTe Quantum Dots Mediated Exciton Trapping for Signal-On Photoelectrochemical Immunoassay of Mycotoxins.

    Science.gov (United States)

    Lin, Youxiu; Zhou, Qian; Tang, Dianping; Niessner, Reinhard; Yang, Huanghao; Knopp, Dietmar

    2016-08-01

    Mycotoxins, highly toxic secondary metabolites produced by many invading species of filamentous fungi, contaminate different agricultural commodities under favorable temperature and humidity conditions. Herein, we successfully devised a novel signal-on photoelectrochemical immunosensing platform for the quantitative monitoring of mycotoxins (aflatoxin B1, AFB1, used as a model) in foodstuffs on the basis of silver nanolabels-assisted ion-exchange reaction with CdTe quantum dots (QDs) mediated hole-trapping. Initially, a competitive-type immunoreaction was carried out on a high-binding microplate by using silver nanoparticle (AgNP)-labeled AFB1-bovine serum albumin (AFB1-BSA) conjugates as the tags. Then, the carried AgNPs with AFB1-BSA were dissolved by acid to release numerous silver ions, which could induce ion-exchange reaction with the CdTe QDs immobilized on the electrode, thus resulting in formation of surface exciton trapping. Relative to pure CdTe QDs, the formed exciton trapping decreased the photocurrent of the modified electrode. In contrast, the detectable photocurrent increased with the increase of target AFB1 in a dynamic working range from 10 pg mL(-1) to 15 ng mL(-1) at a low limit of detection (LOD) of 3.0 pg mL(-1) under optimal conditions. In addition, the as-prepared photoelectrochemical immunosensing platform also displayed high specificity, good reproducibility, and acceptable method accuracy for detecting naturally contaminated/spiked blank peanut samples with consistent results obtained from the referenced enzyme-linked immunosorbent assay (ELISA) method. PMID:27348353

  2. Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode.

    Science.gov (United States)

    Kovarik, Peter; Grivet, Chantal; Bourgogne, Emmanuel; Hopfgartner, Gérard

    2007-01-01

    The present work investigates various method development aspects for the quantitative analysis of pharmaceutical compounds in human plasma using matrix-assisted laser desorption/ionization and multiple reaction monitoring (MALDI-MRM). Talinolol was selected as a model analyte. Liquid-liquid extraction (LLE) and protein precipitation were evaluated regarding sensitivity and throughput for the MALDI-MRM technique and its applicability without and with chromatographic separation. Compared to classical electrospray liquid chromatography/mass spectrometry (LC/ESI-MS) method development, with MALDI-MRM the tuning of the analyte in single MS mode is more challenging due to interfering matrix background ions. An approach is proposed using background subtraction. With LLE and using a 200 microL human plasma aliquot acceptable precision and accuracy could be obtained in the range of 1 to 1000 ng/mL without any LC separation. Approximately 3 s were required for one analysis. A full calibration curve and its quality control samples (20 samples) can be analyzed within 1 min. Combining LC with the MALDI analysis allowed improving the linearity down to 50 pg/mL, while reducing the throughput potential only by two-fold. Matrix effects are still a significant issue with MALDI but can be monitored in a similar way to that used for LC/ESI-MS analysis. PMID:17295425

  3. Free MoS2 Nanoflowers Grown on Graphene by Microwave-Assisted Synthesis as Highly Efficient Non-Noble-Metal Electrocatalysts for the Hydrogen Evolution Reaction

    Science.gov (United States)

    Cao, Jiamu; Zhang, Xuelin; Zhang, Yufeng; Zhou, Jing; Chen, Yinuo; Liu, Xiaowei

    2016-01-01

    Advanced approaches to preparing non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) are considered to be a significant breakthrough in promoting the exploration of renewable resources. In this work, a hybrid material of MoS2 nanoflowers (NFs) on reduced graphene oxide (rGO) was synthesized as a HER catalyst via an environmentally friendly, efficient approach that is also suitable for mass production. Small-sized MoS2 NFs with a diameter of ca. 190 nm and an abundance of exposed edges were prepared by a hydrothermal method and were subsequently supported on rGO by microwave-assisted synthesis. The results show that MoS2 NFs were distributed uniformly on the remarkably reduced GO and preserved the outstanding original structural features perfectly. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER activity, with a small Tafel slope of 80 mV/decade and a low overpotential of 170 mV. PMID:27556402

  4. Reaction kinetics and growth window for plasma-assisted molecular beam epitaxy of Ga2O3: Incorporation of Ga vs. Ga2O desorption

    Science.gov (United States)

    Vogt, Patrick; Bierwagen, Oliver

    2016-02-01

    A detailed study of the reaction kinetics of the plasma-assisted molecular beam epitaxy (MBE) growth of the n-type semiconducting oxide Ga2O3 is presented. The growth rate as a function of gallium flux is measured in situ by laser reflectometry at different growth temperatures (TG) and gallium-to-oxygen ratios (rGa). The flux of the suboxide Ga2O desorbed off the growth surface is identified in situ by line-of-sight quadrupole mass spectroscopy. The measurements reveal the influence of TG and rGa on the competing formation of Ga2O3 and desorption of Ga2O resulting in three different growth regimes: (i) Ga transport limited, (ii) Ga2O desorption limited, and (iii) O transport limited. As a result, we present a growth diagram of gallium oxide. This diagram illustrates the regimes of complete, partial, and no Ga incorporation as a function of TG and rGa, and thus provides guidance for the MBE growth of Ga2O3.

  5. Traffic-Adaptive Routing

    OpenAIRE

    Kammenhuber, Nils

    2011-01-01

    Despite the bursty and highly volatile traffic, routing in the Internet today is optimised only on coarse time scales, as load-adaptive routing is known to induce performance deterioration by causing massive oscillations. We describe ReplEx, an universally applicable distributed algorithm for dynamic routing/traffic engineering, which is based on game theory. We show through extensive realistic simulations that ReplEx does not oscillate, and that it achieves performance gains comparable to tr...

  6. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    OpenAIRE

    Ahmed Salama; Mike Neumann; Christina Günter; Andreas Taubert

    2014-01-01

    Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show t...

  7. Contact Graph Routing

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic

  8. Synthesis of aqueous ferrofluids of Zn{sub x}Fe{sub 3-x}O{sub 4} nanoparticles by citric acid assisted hydrothermal-reduction route for magnetic hyperthermia applications

    Energy Technology Data Exchange (ETDEWEB)

    Behdadfar, Behshid, E-mail: bbehdadfar@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, Ahmad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi-Aliabadi, Hojjat [School of Pharmacy, Isfahan Pharmaceutical Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Mozaffari, Morteza [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-07-15

    Superparamagnetic and monodispersed aqueous ferrofluids of Zn substituted magnetite nanoparticles (Zn{sub x}Fe{sub 3-x}O{sub 4}, x=0, 0.25, 0.3, 0.37 and 0.4) were synthesized via hydrothermal-reduction route in the presence of citric acid, which is a facile, low energy and environmental friendly method. The synthesized nanoparticles were characterized by X ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and the dynamic light scattering (DLS) method. The results showed that a certain amount of citric acid was required to obtain single phase Zn substituted magnetite nanoparticles. Citric acid acted as a modulator and reducing agent in the formation of spinel structure and controlled nanoparticle size and crystallinity. Mean particle sizes of the prepared nanoparticles were around 10 nm. The results that are obtained from XRD, magnetic and power loss measurements showed that the crystallinity, saturation magnetization (M{sub S}) and loss power of the synthesized ferrofluids were all influenced by the substitution of Zn in the structure of magnetite. The Zn substituted magnetite nanoparticles obtained by this route showed a good stability in aqueous medium (pH 7) and hydrodynamic sizes below 100 nm and polydispersity indexes below 0.2. The calculated intrinsic loss power (ILP) for the sample x=0.3 (e.g. 2.36 nH m{sup 2}/kg) was comparable to ILP of commercial ferrofluids with similar hydrodynamic sizes. - Highlights: Black-Right-Pointing-Pointer We synthesized Zn substituted magnetite nanoparticles via hydrothermal-reduction route. Black-Right-Pointing-Pointer We used citric acid as a reducing agent in this route. Black-Right-Pointing-Pointer This route is a facile, low energy and environmental friendly method. Black-Right-Pointing-Pointer The nanoparticles obtained by this route were superparamagnetic and stable in water. Black-Right-Pointing-Pointer The calculated intrinsic

  9. REDUCING BURST PACKET LOSS THROUGH ROUTE-FREE FORWARDING

    Institute of Scientific and Technical Information of China (English)

    Ma Hailong; Guo Yunfei; Cheng Dongnian; Zhang Jianwei

    2010-01-01

    It is well known that today's inter-domain routing protocol,Border Gateway Protocol (BGP),converges slowly during network failures. Due to the distribution nature of Internet routing decisions and the rate-limiting timer Minimum Route Advertisement Interval (MRAI) of BGP,unavoidable convergence latency is introduced in reaction to network changes. During the period of convergence temporarily routing table inconsistencies cause short-term routing blackholes and loops which result in widespread temporary burst packet loss. In this paper,we present ROute-Free Forwarding (ROFF) - a novel technique for packet delivering continuously during periods of convergence. With slightly modifications on IP packet header and BGP,route loops and blackholes can be avoided. Our preliminary evaluation demonstrates that ROFF succeeds in reducing the number of Autonomous Systems (ASes) which experience burst packet loss and the duration of packet loss.

  10. Ultra-fast quantitation of saquinavir in human plasma by matrix-assisted laser desorption/ionization and selected reaction monitoring mode detection.

    Science.gov (United States)

    Wagner, Michel; Varesio, Emmanuel; Hopfgartner, Gérard

    2008-09-01

    We present herein an ultra-fast quantitative assay for the quantitation of saquinavir in human plasma, without prior chromatographic separation, with matrix-assisted laser desorption/ionization using the selected reaction monitoring quantitation mode (MALDI-SRM/MS). The method was found to be linear from 5 to 10,000 ng/ml using pentadeuterated saquinavir (SQV-d5) as an internal standard, and from 5 to 1000 ng/ml using reserpine as internal standard (IS). Accuracy and precision were in the range of 101-108%, 3.9-11% with SQV-d5 and in the range 93-108%, 3.5-15% with reserpine. Plasma samples (250 microl) were extracted with a mixture of ethyl acetate/hexane. MALDI spotting of the extract was automated using electrodeposition and the dried droplet method using alpha-cyano-4-hydroxycinnamic acid (CHCA) as matrix. A 96 spots MALDI plate was prepared within 20 min in a fully unattended manner. Each sample was spotted four times and quantitation was based on the average of their analyte/IS area ratio. Samples were analyzed on a triple quadrupole linear ion trap (QqQ(LIT)) equipped with a high repetition laser source (1000 Hz). The analysis time of one sample was approximately 6 s, therefore 96 samples could be analyzed in less than 10 min. With liquid-liquid extraction sample preparation no significant matrix effects were observed. Moreover, the assay showed sufficient selectivity for samples to be analyzed at the lower limit of quantification (LLOQ) in the presence of other antiretroviral drugs, without prior chromatographic steps. In parallel, to assess the selectivity of the assay with real samples, a liquid chromatography (LC)-SRM/MS method was developed and a cross validation with clinical samples was successfully performed. PMID:18657486

  11. Understanding individual routing behaviour.

    Science.gov (United States)

    Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

    2016-03-01

    Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions. PMID:26962031

  12. Sleep-Route: Routing through Sleeping Sensors

    OpenAIRE

    Sarkar, Chayan; Rao, Vijay S.; Prasad, R. Venkatesha

    2014-01-01

    In this article, we propose an energy-efficient data gathering scheme for wireless sensor network called Sleep-Route, which splits the sensor nodes into two sets - active and dormant (low-power sleep). Only the active set of sensor nodes participate in data collection. The sensing values of the dormant sensor nodes are predicted with the help of an active sensor node. Virtual Sensing Framework (VSF) provides the mechanism to predict the sensing values by exploiting the data correlation among ...

  13. Dahomey Breeding Bird Survey Route

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Document contains route directions and map for the naitonal Dahomey BBS route. Includes milage for where specific listening stations are located along the route...

  14. Hollow nanoporous covalent triazine frameworks via acid vapor-assisted solid phase synthesis for enhanced visible light photoactivity

    KAUST Repository

    Huang, Wei

    2016-04-11

    Herein, we report a novel trifluoromethanesulfonic acid vapor-assisted solid phase synthetic method to construct nanoporous covalent triazine frameworks with highly ordered hollow interconnected pores under mild reaction conditions. This unique solid state synthetic route allows not only the avoidance of undesired side reactions caused by traditional high temperature synthesis, but also the maintaining of defined and precise optical and electronic properties of the nonporous triazine frameworks. Promising photocatalytic activity of the polytriazine networks was demonstrated in the photoreduction reaction of 4-nitrophenol into 4-aminophenol under visible light irradiation.

  15. Class network routing

    Science.gov (United States)

    Bhanot, Gyan; Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Takken, Todd E.; Vranas, Pavlos M.

    2009-09-08

    Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

  16. Computer Assisted Design, Prediction, and Execution of Economical Organic Syntheses

    Science.gov (United States)

    Gothard, Nosheen Akber

    The synthesis of useful organic molecules via simple and cost-effective routes is a core challenge in organic chemistry. In industry or academia, organic chemists use their chemical intuition, technical expertise and published procedures to determine an optimal pathway. This approach, not only takes time and effort, but also is cost prohibitive. Many potential optimal routes scratched on paper fail to get experimentally tested. In addition, with new methods being discovered daily are often overlooked by established techniques. This thesis reports a computational technique that assist the discovery of economical synthetic routes to useful organic targets. Organic chemistry exists as a network where chemicals are connected by reactions, analogous to citied connected by roads in a geographic map. This network topology of organic reactions in the network of organic chemistry (NOC) allows the application of graph-theory to devise algorithms for synthetic optimization of organic targets. A computational approach comprised of customizable algorithms, pre-screening filters, and existing chemoinformatic techniques is capable of answering complex questions and perform mechanistic tasks desired by chemists such as optimization of organic syntheses. One-pot reactions are central to modern synthesis since they save resources and time by avoiding isolation, purification, characterization, and production of chemical waste after each synthetic step. Sometimes, such reactions are identified by chance or, more often, by careful inspection of individual steps that are to be wired together. Algorithms are used to discover one-pot reactions and validated experimentally. Which demonstrate that the computationally predicted sequences can indeed by carried out experimentally in good overall yields. The experimental examples are chosen to from small networks of reactions around useful chemicals such as quinoline scaffolds, quinoline-based inhibitors of phosphoinositide 3-kinase delta (PI3

  17. Modeling Routing Overhead Generated by Wireless Reactive Routing Protocols

    CERN Document Server

    Javaid, Nadeem; Javaid, Akmal; Malik, Shahzad A

    2011-01-01

    In this paper, we have modeled the routing over- head generated by three reactive routing protocols; Ad-hoc On-demand Distance Vector (AODV), Dynamic Source Routing (DSR) and DYnamic MANET On-deman (DYMO). Routing performed by reactive protocols consists of two phases; route discovery and route maintenance. Total cost paid by a protocol for efficient routing is sum of the cost paid in the form of energy consumed and time spent. These protocols majorly focus on the optimization performed by expanding ring search algorithm to control the flooding generated by the mechanism of blind flooding. So, we have modeled the energy consumed and time spent per packet both for route discovery and route maintenance. The proposed framework is evaluated in NS-2 to compare performance of the chosen routing protocols.

  18. Modeling Routing Overhead Generated by Wireless Proactive Routing Protocols

    CERN Document Server

    Javaid, Nadeem; Javaid, Akmal; Malik, Shahzad A

    2011-01-01

    In this paper, we present a detailed framework consisting of modeling of routing overhead generated by three widely used proactive routing protocols; Destination-Sequenced Distance Vector (DSDV), Fish-eye State Routing (FSR) and Optimized Link State Routing (OLSR). The questions like, how these protocols differ from each other on the basis of implementing different routing strategies, how neighbor estimation errors affect broadcast of route requests, how reduction of broadcast overhead achieves bandwidth, how to cope with the problem of mobility and density, etc, are attempted to respond. In all of the above mentioned situations, routing overhead and delay generated by the chosen protocols can exactly be calculated from our modeled equations. Finally, we analyze the performance of selected routing protocols using our proposed framework in NS-2 by considering different performance parameters; Route REQuest (RREQ) packet generation, End-to-End Delay (E2ED) and Normalized Routing Load (NRL) with respect to varyi...

  19. mizuRoute version 1: a river network routing tool for a continental domain water resources applications

    Science.gov (United States)

    Mizukami, Naoki; Clark, Martyn P.; Sampson, Kevin; Nijssen, Bart; Mao, Yixin; McMillan, Hilary; Viger, Roland J.; Markstrom, Steve L.; Hay, Lauren E.; Woods, Ross; Arnold, Jeffrey R.; Brekke, Levi D.

    2016-06-01

    This paper describes the first version of a stand-alone runoff routing tool, mizuRoute. The mizuRoute tool post-processes runoff outputs from any distributed hydrologic model or land surface model to produce spatially distributed streamflow at various spatial scales from headwater basins to continental-wide river systems. The tool can utilize both traditional grid-based river network and vector-based river network data. Both types of river network include river segment lines and the associated drainage basin polygons, but the vector-based river network can represent finer-scale river lines than the grid-based network. Streamflow estimates at any desired location in the river network can be easily extracted from the output of mizuRoute. The routing process is simulated as two separate steps. First, hillslope routing is performed with a gamma-distribution-based unit-hydrograph to transport runoff from a hillslope to a catchment outlet. The second step is river channel routing, which is performed with one of two routing scheme options: (1) a kinematic wave tracking (KWT) routing procedure; and (2) an impulse response function - unit-hydrograph (IRF-UH) routing procedure. The mizuRoute tool also includes scripts (python, NetCDF operators) to pre-process spatial river network data. This paper demonstrates mizuRoute's capabilities to produce spatially distributed streamflow simulations based on river networks from the United States Geological Survey (USGS) Geospatial Fabric (GF) data set in which over 54 000 river segments and their contributing areas are mapped across the contiguous United States (CONUS). A brief analysis of model parameter sensitivity is also provided. The mizuRoute tool can assist model-based water resources assessments including studies of the impacts of climate change on streamflow.

  20. Computer Network Routing with a Fuzzy Neural Network

    OpenAIRE

    Brande, Julia K. Jr.

    1997-01-01

    The growing usage of computer networks is requiring improvements in network technologies and management techniques so users will receive high quality service. As more individuals transmit data through a computer network, the quality of service received by the users begins to degrade. A major aspect of computer networks that is vital to quality of service is data routing. A more effective method for routing data through a computer network can assist with the new problems be...

  1. Multihop Wireless Networks Opportunistic Routing

    CERN Document Server

    Zeng, Kai; Li, Ming

    2011-01-01

    This book provides an introduction to opportunistic routing an emerging technology designed to improve the packet forwarding reliability, network capacity and energy efficiency of multihop wireless networks This book presents a comprehensive background to the technological challenges lying behind opportunistic routing. The authors cover many fundamental research issues for this new concept, including the basic principles, performance limit and performance improvement of opportunistic routing compared to traditional routing, energy efficiency and distributed opportunistic routing protocol desig

  2. Collective network routing

    Science.gov (United States)

    Hoenicke, Dirk

    2014-12-02

    Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

  3. Roots and routes

    DEFF Research Database (Denmark)

    Christensen, Ann-Dorte; Jensen, Sune Qvotrup

    2011-01-01

    arguing that there is a dynamic interplay between roots and routes in people's lives. The empirical point of departure is narratives about roots and routes by ethnic minorities settled in Aalborg East, an underprivileged neighbourhood in northern Denmark. One of the main findings is a gap between the...... somewhat paradoxical finding is that it appears to be more difficult for transnational migrants to maintain their roots in the country of origin when they go back than it was to establish new roots in the host country...

  4. Torch Route Twist

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    San Francisco changes Olympic flame route due to security fears The city of San Francisco,the only North American stop for the 2008 Beijing Olympic torch,surprised thousands of supporters,demon- strators and visitors on April 9,by com- pletely changing the planned torch route at the last minute without notification. As scheduled,the torch was expected to start from the McCovey Cove in the south- east of the city at 1:00 p.m.before heading along the waterfront northbound to famous tourist spot Fisherman’s Wharf and finally

  5. Route based forecasting

    Science.gov (United States)

    Zuurendonk, I. W.; Wokke, M. J. J.

    2009-09-01

    Road surface temperatures can differ several degrees on a very short distance due to local effects. In order to get more insight in the local temperature differences and to develop safer gritting routes, Meteogroup has developed a system for route based temperature forecasting. The standard version of the road model is addressed to forecast road surface temperature and condition for a specific location. This model consists of two parts. First a physical part, based on the energy balance equations. The second part of the model performs a statistical correction on the calculated physical road surface temperature. The road model is able to create a forecast for one specific location. From infrared measurements, we know that large local differences in road surface temperature exist on a route. Differences can be up to 5 degrees Celsius over a distance of several hundreds of meters. Based on those measurements, the idea came up to develop a system that forecasts road surface temperature and condition for an entire route: route based forecasting. The route is split up in sections with equal properties. For each section a temperature and condition will be calculated. The main factors that influence the road surface temperature are modelled in this forecasting system: •The local weather conditions: temperature, dew point temperature, wind, precipitation, weather type, cloudiness. •The sky view: A very sheltered place will receive less radiation during daytime and emit less radiation during nighttime. For a very open spot, the effects are reversed. •The solar view: A road section with trees on the southern side, will receive less solar radiation during daytime than a section with tress on the southern side. The route based forecast shows by means of a clear Google Maps presentation which sections will be slippery at what time of the coming night. The final goal of this type of forecast, is to make dynamical gritting possible: a variable salt amount and a different

  6. SET-Routes programme

    CERN Multimedia

    Marietta Schupp, EMBL Photolab

    2008-01-01

    Dr Sabine Hentze, specialist in human genetics, giving an Insight Lecture entitled "Human Genetics – Diagnostics, Indications and Ethical Issues" on 23 September 2008 at EMBL Heidelberg. Activities in a achool in Budapest during a visit of Angela Bekesi, Ambassadors for the SET-Routes programme.

  7. SET-Routes programme

    CERN Multimedia

    CERN audiovisual service

    2009-01-01

    The SET-Routes programme, launched in 2007 with the goal of attracting girls and young women to careers in science, came to an end in April this year. The result of a collaboration between EMBL, EMBO and CERN, the programme established a network of "ambassadors", women scientists who went out to talk about their careers in science at schools and universities across Europe.

  8. Whirlpool routing for mobility

    KAUST Repository

    Lee, Jung Woo

    2010-01-01

    We present the Whirlpool Routing Protocol (WARP), which efficiently routes data to a node moving within a static mesh. The key insight in WARP\\'s design is that data traffic can use an existing routing gradient to efficiently probe the topology, repair the routing gradient, and communicate these repairs to nearby nodes. Using simulation, controlled testbeds, and real mobility experiments, we find that using the data plane for topology maintenance is highly effective due to the incremental nature of mobility updates. WARP leverages the fact that converging flows at a destination make the destination have the region of highest traffic. We provide a theoretical basis for WARP\\'s behavior, defining an "update area" in which the topology must adjust when a destination moves. As long as packets arrive at a destination before it moves outside of the update area, WARP can repair the topology using the data plane. Compared to existing protocols, such as DYMO and HYPER, WARP\\'s packet drop rate is up to 90% lower while sending up to 90% fewer packets.

  9. A diversity-oriented synthesis of pyrazolo[4,3-f]quinoline derivatives with potential bioactivities via microwave-assisted multi-component reactions.

    Science.gov (United States)

    Shi, Feng; Zhang, Shu; Wu, Shan-Shan; Gao, Yuan; Tu, Shu-Jiang

    2011-05-01

    Six new series of pyrazolo[4,3-f]quinoline derivatives with potential bioactivities were synthesized by the three-component reactions of aromatic aldehydes, 5-aminoindazole, and various cyclic 1,3-dicarbonyl compounds under microwave irradiation. This protocol has the valuable features of structural diversity of products, broader substrate scope, operational simplicity, high yields, and short reaction time. Moreover, the structure of compound 88a was confirmed by an X-ray crystallographic analysis and attested to the chemoselectivity of reaction where 1-methyl barbituric acid participated. PMID:20814822

  10. Issues of Routing in VANET

    OpenAIRE

    Raja, Umar Waqas; Mustafa, Bilal

    2010-01-01

    Vehicular Ad Hoc Network (VANET) is a sub class of mobile ad hoc networks. VANET provides wireless communication among vehicles and vehicle to road side equipments. The communication between vehicles is used for safety, comfort and for entertainment as well. The performance of communication depends on how better the routing takes place in the network. Routing of data depends on the routing protocols being used in network. In this study we investigated about different ad hoc routing protocols ...

  11. Alternative iron making routes

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, P.; Sharma, T. [Indian School of Mines, Dhanbad (India)

    2002-07-01

    The versatile route of iron production 'blast furnace' technique is being replaced by widely accepted Corex technology, Midrex process using Fastmelt ironmaking, eco-friendly Romelt process, more innovative Ausmelt & Hismelt technology, TATA KORF Mini blast furnace improvement, 'quickest iron through Orbiting Plasma', Direct iron ore smelting process, Conred, AISI-Hyl, Inred processes, Direct iron ore reduction methods, their comparison and proposed modifications. 18 refs., 11 figs., 14 tabs.

  12. Effective local dynamic routing strategy for air route networks

    Institute of Scientific and Technical Information of China (English)

    Wu Wenjun; Zhao Lingxi

    2015-01-01

    With the rapid development of air transportation, network service ability has attracted a lot of attention in academe. Aiming to improve the throughput of the air route network (ARN), we propose an effective local dynamic routing strategy in this paper. Several factors, such as the rout-ing distance, the geographical distance and the real-time local traffic, are taken into consideration. When the ARN is in the normal free-flow state, the proposed strategy can recover the shortest path routing (SPR) strategy. When the ARN undergoes congestion, the proposed strategy changes the paths of flights based on the real-time local traffic information. The throughput of the Chinese air route network (CARN) is evaluated. Results confirm that the proposed strategy can significantly improve the throughput of CARN. Meanwhile, the increase in the average flying distance and time is tiny. Results also indicate the importance of the distance related factors in a routing strategy designed for the ARN.

  13. Rapid synthesis of polypyrrole nanospheres by greener mechanochemical route

    International Nuclear Information System (INIS)

    A simple, rapid and efficient route to prepare polypyrrole nanospheres by template-free method is described. This greener route has advantages in terms of good yield, short reaction time, neat conditions and cost-effectiveness. The resultant polymeric material was characterized by field-emission scanning electron microscopy, X-ray scattering, cyclic voltammetry, chronoamperometry, Fourier transform infrared spectroscopy and UV-visible spectroscopy. From these studies it is confirmed that the as prepared polypyrrole nanospheres possesses good physicochemical properties.

  14. Enhanced Sodium Ion Storage Behavior of P2-Type Na(2/3)Fe(1/2)Mn(1/2)O2 Synthesized via a Chelating Agent Assisted Route.

    Science.gov (United States)

    Bai, Ying; Zhao, Lixiang; Wu, Chuan; Li, Hui; Li, Yu; Wu, Feng

    2016-02-01

    On the basis of resource abundance and low cost, high capacity layered P2-type Na2/3Fe1/2Mn1/2O2 material is regarded as a potential cathode material for sodium-ion batteries but suffers from its unstable structure during cycling. In this work, P2-type Na2/3Fe1/2Mn1/2O2 layered materials were synthesized by a chelating agent assisted sol-gel method with NH3·H2O. With the addition of NH3·H2O and the control of the synthesis conditions, highly active material with a more stable structure and better electrochemical performance was obtained. Furthermore, the influences of structure changes during different voltage ranges (1.5-4.0 V and 1.5-4.3 V vs Na(+)/Na) on the Na(+) storage behaviors were also evaluated and compared. It is confirmed that, when being charged to 4.2 V, an OP4-type phase emerges, which can reduce the damage by the gilding of the MeO2 layers but leads to an unstable crystal structure. For long-term cycling, it is preferred to cut off at 4.0 V rather than at 4.3 V. For the optimized P2-type Na2/3Fe1/2Mn1/2O2 calcined at 900 °C, a discharge capacity of 92 mAh/g remains after 40 cycles in the voltage range of 1.5-4.0 V, and the Coulombic efficiency remains 100%. PMID:26732022

  15. Stochastic vehicle routing with recourse

    DEFF Research Database (Denmark)

    Gørtz, Inge Li; Nagarajan, Viswanath; Saket, Rishi

    We study the classic Vehicle Routing Problem in the setting of stochastic optimization with recourse. StochVRP is a two-stage problem, where demand is satisfied using two routes: fixed and recourse. The fixed route is computed using only a demand distribution. Then after observing the demand...... instantiations, a recourse route is computed - but costs here become more expensive by a factor λ. We present an O(log2n ·log(nλ))-approximation algorithm for this stochastic routing problem, under arbitrary distributions. The main idea in this result is relating StochVRP to a special case of submodular...

  16. Robustness of airline route networks

    Science.gov (United States)

    Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

    2016-03-01

    Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

  17. Guidelines for applying criteria to designate routes for transporting hazardous materials. Final report

    International Nuclear Information System (INIS)

    These guidelines were prepared to assist State and local officials in the analysis of alternate routes to be used by highway vehicles transportating hazardous materials. A methodology for assessing comparative risks of routing alternatives is discussed and demonstrated through a hypothetical example. Mathematical models are provided for situations in which measured local data may not be easily obtained or adequate

  18. Personal continuous route pattern mining

    Institute of Scientific and Technical Information of China (English)

    Qian YE; Ling CHEN; Gen-cai CHEN

    2009-01-01

    In the daily life, people often repeat regular routes in certain periods. In this paper, a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status, the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining, a novel pattern mining algorithm, continuous route pattern mining (CRPM), is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.

  19. Conventional and microwave-assisted multicomponent reaction of alkyne, halide and sodium azide catalyzed by copper apatite as heterogeneous base and catalyst in water

    Directory of Open Access Journals (Sweden)

    Sandip Kale

    2012-04-01

    Full Text Available The conventional and microwave assisted multicomponent synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide using copper apatite catalyst in water is reported. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the copper hydroxyapatite. The catalyst could be used ten times without further treatment and activation under controlled microwave heating. The protocol was also applicable for various alkynes and halides which affords desired product in good to excellent yield.

  20. A simple route to vertical array of quasi-1D ZnO nanofilms on FTO surfaces: 1D-crystal growth of nanoseeds under ammonia-assisted hydrolysis process

    Directory of Open Access Journals (Sweden)

    Abd Rahman Mohd Yusri

    2011-01-01

    Full Text Available Abstract A simple method for the synthesis of ZnO nanofilms composed of vertical array of quasi-1D ZnO nanostructures (quasi-NRs on the surface was demonstrated via a 1D crystal growth of the attached nanoseeds under a rapid hydrolysis process of zinc salts in the presence of ammonia at room temperature. In a typical procedure, by simply controlling the concentration of zinc acetate and ammonia in the reaction, a high density of vertically oriented nanorod-like morphology could be successfully obtained in a relatively short growth period (approximately 4 to 5 min and at a room-temperature process. The average diameter and the length of the nanostructures are approximately 30 and 110 nm, respectively. The as-prepared quasi-NRs products were pure ZnO phase in nature without the presence of any zinc complexes as confirmed by the XRD characterisation. Room-temperature optical absorption spectroscopy exhibits the presence of two separate excitonic characters inferring that the as-prepared ZnO quasi-NRs are high-crystallinity properties in nature. The mechanism of growth for the ZnO quasi-NRs will be proposed. Due to their simplicity, the method should become a potential alternative for a rapid and cost-effective preparation of high-quality ZnO quasi-NRs nanofilms for use in photovoltaic or photocatalytics applications. PACS: 81.07.Bc; 81.16.-c; 81.07.Gf.

  1. Linear Network Fractional Routing

    Directory of Open Access Journals (Sweden)

    S.ASOKAN,

    2011-07-01

    Full Text Available A Network is a finite directed acyclic graph with source messages from a fixed alphabet and message demands at sink nodes. Linear Programming is an algorithm design method. It can be used whenthe solution to a problem can be viewed as the result of a sequence of decisions. The Linear Programming model for the network problem where in every variable has a value one or zero. The problem is todetermine a method of transmitting the messages through the network such that all sink demands are satisfied. We will prove fractional routing capacity for some solvable network using Linear Programmingmodel.

  2. Uncovering the Missing Routes

    DEFF Research Database (Denmark)

    Tsirogiannis, Constantinos; Tsirogiannis, Christos

    2016-01-01

    In the present work we model and analyse the global network of the illegal trade in antiquities. Our goal is to use this network to estimate for any given artefact the potential sequence of people in the network among whom this artefact was traded. For this reason, we have implemented and evaluated...... three different algorithms that estimate potential trade routes within the network. We also evaluate the performance of a popular method that estimates direct links in the network, links which may not have been documented in the police records....

  3. Electrochemical performance of Li4Mn5O12 nano-crystallites prepared by spray-drying-assisted solid state reactions

    International Nuclear Information System (INIS)

    Nanosized Li4Mn5O12 has been synthesized by a spray-drying-assisted solid state method. The effect of spray drying and drying temperature on the microstructure and electrochemical performance of the final products has been investigated. The microstructure of the products has been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The electrochemical performance of the products has been studied by galvanostatic cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It has been found that the products prepared with a spray-drying pretreatment of the precursor exhibit a smaller grain size and a narrower size distribution than that prepared without the pretreatment. Among the three samples with a precursor pretreatment, that pretreated at 250 oC shows the best electrochemical performance due to the smallest grain size of below 50 nm and the narrowest size distribution.

  4. Enhancement of charge transition from donor to acceptor in organic and biochemical reactions by the intermediate-mode-assisted tunneling mechanism

    International Nuclear Information System (INIS)

    The intermediate-mode-assisted tunneling mechanism is shown to be relevant for the control of electron (/hole/energy) transfer in donor-bridge-acceptor based symmetric molecular electronic systems. In this case the donor and the acceptor are superpositions of two practically degenerate eigenstates of the system. A molecular eigenstate of the system, which is mainly localized on the bridge, serves as intermediate state. Upon a small symmetry preserving variation of the bridge site geometry this intermediate state is coupled only to one of the two practically degenerate states. Our approach gives the tools to design a molecular switch where 100% ultrafast electron/hole transition occurs. As an illustrative numerical example the electron/hole transition in a cation radical of a polycyclic analogue of norbornadienone (PC-NBDO) molecule is calculated. We observe that, because of a sudden stretch in the CO bond of the bridge site, the electron transfer time has been decreased from infinity to 11 femtoseconds.

  5. Asymmetric effect of route-length difference and bottleneck on route choice in two-route traffic system

    Science.gov (United States)

    Hino, Yuki; Nagatani, Takashi

    2015-06-01

    We study the traffic behavior in the asymmetric two-route traffic system with real-time information. In the asymmetric two-route system, the length on route A is different from that on route B and there exists a bottleneck on route A. We extend the symmetric two-route dynamic model to the asymmetric case. We investigate the asymmetric effects of the route-length difference and bottleneck on the route choice with real-time information. The travel time on each route depends on the road length, bottleneck, and vehicular density. We derive the dependence of the travel time and mean density on the route-length ratio. We show where, when, and how the congestion occurs by the route choice in the asymmetric two-route system. We clarify the effect of the route-length ratio on the traffic behavior in the route choice.

  6. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    Directory of Open Access Journals (Sweden)

    Ahmed Salama

    2014-09-01

    Full Text Available Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show that the cells proliferate on the hybrid materials suggesting that the ionic liquid-based process yields materials that are potentially useful as scaffolds for regenerative therapies.

  7. Central Control Over Distributed Routing

    OpenAIRE

    Vissicchio, Stefano; Tilmans, Olivier; Vanbever, Laurent; Rexford, Jennifer; ACM SIGCOMM

    2015-01-01

    Centralizing routing decisions offers tremendous flexibility, but sacrifices the robustness of distributed protocols. In this paper, we present Fibbing, an architecture that achieves both flexibility and robustness through central control over distributed routing. Fibbing introduces fake nodes and links into an underlying link-state routing protocol, so that routers compute their own forwarding tables based on the augmented topology. Fibbing is expressive, and readily supports flexible load b...

  8. Effects of N{sub 2}O gas addition on the properties of ZnO films grown by catalytic reaction-assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Kanji, E-mail: kyasui@vos.nagaokaut.ac.jp; Morioka, Makoto; Kanauchi, Shingo; Ohashi, Yuki; Kato, Takahiro; Tamayama, Yasuhiro [Department of Electrical, Electronic, and Information Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

    2015-11-15

    The influence of N{sub 2}O gas addition on the properties of zinc oxide (ZnO) films grown on a-plane (11–20) sapphire (a-Al{sub 2}O{sub 3}) substrates was investigated, using a chemical vapor deposition method based on the reaction between dimethylzinc and high-temperature H{sub 2}O produced by a catalytic H{sub 2}-O{sub 2} reaction on platinum (Pt) nanoparticles. The addition of N{sub 2}O was found to increase the size of the crystalline facets and to improve the crystal orientation along the c-axis. The electron mobility at 290 K was also increased to 234 cm{sup 2}/Vs following the addition of N{sub 2}O gas at a pressure of 3.2 × 10{sup −3 }Pa. In addition, the minimum full width at half maximum of the most intense photoluminescence peak derived from neutral donor bound excitons at 10 K decreased to 0.6 meV by the addition of N{sub 2}O gas at a pressure of 3.1 × 10{sup −2 }Pa.

  9. Alternative routes of insulin delivery

    Institute of Scientific and Technical Information of China (English)

    Ranjith K. Krishnankutty; Aju Mathew; Saikiran K. Sedimbi; Shrikumar Suryanarayan; Carani B. Sanjeevi

    2009-01-01

    Parenteral route of insulin administration has been the mode of treatment for all Type 1 diabetics and Type 2 diabetics with complications. Patient compliance has really been a major concern for this route of administration. Several alternative routes of administration are under consideration for effective glycemic control, including oral, inhaled, buccal, nasal, and patch routes. One of the approaches involving inhaled insulin has now reached the market. Several other candidates may reach the market in the near future, the promising one being oral insulin.

  10. Southern States' Routing Agency Report

    International Nuclear Information System (INIS)

    The Southern States' Routing Agency Report is a compendium of 16-southern states' routing program for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed

  11. A Primer of Multicast Routing

    CERN Document Server

    Rosenberg, Eric

    2012-01-01

    Whereas unicast routing determines a path from one source node to one destination node, multicast routing determines a path from one source to many destinations, or from many sources to many destinations. We survey multicast routing methods for when the set of destinations is static, and for when it is dynamic. While most of the methods we review are tree based, some non-tree methods are also discussed. We survey results on the shape of multicast trees, delay constrained multicast routing, aggregation of multicast traffic, inter-domain multicast, and multicast virtual private networks. We focu

  12. A Wire-speed Routing Lookup Algorithm Based on TCAM

    Institute of Scientific and Technical Information of China (English)

    李小勇; 王志恒; 白英彩; 刘刚

    2004-01-01

    An internal structure of Ternary Content Addressable Memory (TCAM) is designed and a Sorting Prefix Block (SPB) algorithm is presented, which is a wire-speed routing lookup algorithm based on TCAM. SPB algorithm makes use of the parallelism of TCAM adequately, and improves the utilization of TCAM by optimum partitions. With the aid of effective management algorithm and memory image, SPB separates critical searching from assistant searching, and improves the searching effect. One performance test indicates that this algorithm can work with different TCAM to meet the requirement of wire-speed routing lookup.

  13. Route Elimination Heuristic for Vehicle Routing Problem with Time Windows

    Directory of Open Access Journals (Sweden)

    Sándor Csiszár

    2005-11-01

    Full Text Available The paper deals with the design of a route elimination (RE algorithm for thevehicle routing problem with time windows (VRPTW. The problem has two objectives, oneof them is the minimal number of routes the other is the minimal cost. To cope with theseobjectives effectively two-phase solutions are often suggested in the relevant literature. Inthe first phase the main focus is the route elimination, in the second one it is the costreduction. The algorithm described here is a part of a complete VRPWT study. The methodwas developed by studying the graph behaviour during the route elimination. For thispurpose a model -called “Magic Bricks” was developed. The computation results on theSolomon problem set show that the developed algorithm is competitive with the best ones.

  14. Inter-Domain Routing Under Scrutiny: Routing Models and Alternative Routing Architectures

    OpenAIRE

    Mühlbauer, Wolfgang

    2010-01-01

    Inter-Domain Routing, also die Verkehrslenkung zwischen Autonomen Systemen (ASen), ist seit Jahren ein lebendiges Forschungsgebiet. Hauptursache hierfür ist dessen Komplexität: Zusammenspiel zwischen Interior und Exterior Gateway Protokollen, eine Vielfalt unterschiedlicher Routing Policies, komplexe Verbindungsstrukturen zwischen ASen, usw. Ein wesentliches Ziel der vorliegenden Dissertation besteht in einem verbesserten Allgemeinverständnis des Inter-Domain Routings. Desweiteren werden neua...

  15. Routing Discovery Algorithm Using Parallel Chase Packet

    OpenAIRE

    Amera Al-Ameri; Muneer Bani Yassein; Khamayseh, Yaser M.

    2013-01-01

    On demand routing protocols for ad hoc networks such as Ad Hoc On Demand Distance Vector (AODV) initiate a route discovery process when a route is needed by flooding the network with a route request packet. The route discovery process in such protocols depends on a simple flooding as a broadcast technique due to its simplicity. Simple flooding results in packet congestion, route request overhead and excessive collisions, namely broadcast storm problem. A number of routing techniques have been...

  16. A solvent evaporation route towards fabrication of hierarchically porous ZSM-11 with highly accessible mesopores

    DEFF Research Database (Denmark)

    Song, Wen; Liu, Zhiting; Liu, Liping;

    2015-01-01

    A route to generate hierarchically porous zeolite ZSM-11 has been paved via solvent evaporation induced self-assembly assisted by hexadecyltrimethoxysilane to produce a preformed dry gel, followed by its subsequent transformation into zeolite via steam-assisted-crystallization. The crystallization...

  17. Producing gestures facilitates route learning.

    Directory of Open Access Journals (Sweden)

    Wing Chee So

    Full Text Available The present study investigates whether producing gestures would facilitate route learning in a navigation task and whether its facilitation effect is comparable to that of hand movements that leave physical visible traces. In two experiments, we focused on gestures produced without accompanying speech, i.e., co-thought gestures (e.g., an index finger traces the spatial sequence of a route in the air. Adult participants were asked to study routes shown in four diagrams, one at a time. Participants reproduced the routes (verbally in Experiment 1 and non-verbally in Experiment 2 without rehearsal or after rehearsal by mentally simulating the route, by drawing it, or by gesturing (either in the air or on paper. Participants who moved their hands (either in the form of gestures or drawing recalled better than those who mentally simulated the routes and those who did not rehearse, suggesting that hand movements produced during rehearsal facilitate route learning. Interestingly, participants who gestured the routes in the air or on paper recalled better than those who drew them on paper in both experiments, suggesting that the facilitation effect of co-thought gesture holds for both verbal and nonverbal recall modalities. It is possibly because, co-thought gesture, as a kind of representational action, consolidates spatial sequence better than drawing and thus exerting more powerful influence on spatial representation.

  18. Producing gestures facilitates route learning.

    Science.gov (United States)

    So, Wing Chee; Ching, Terence Han-Wei; Lim, Phoebe Elizabeth; Cheng, Xiaoqin; Ip, Kit Yee

    2014-01-01

    The present study investigates whether producing gestures would facilitate route learning in a navigation task and whether its facilitation effect is comparable to that of hand movements that leave physical visible traces. In two experiments, we focused on gestures produced without accompanying speech, i.e., co-thought gestures (e.g., an index finger traces the spatial sequence of a route in the air). Adult participants were asked to study routes shown in four diagrams, one at a time. Participants reproduced the routes (verbally in Experiment 1 and non-verbally in Experiment 2) without rehearsal or after rehearsal by mentally simulating the route, by drawing it, or by gesturing (either in the air or on paper). Participants who moved their hands (either in the form of gestures or drawing) recalled better than those who mentally simulated the routes and those who did not rehearse, suggesting that hand movements produced during rehearsal facilitate route learning. Interestingly, participants who gestured the routes in the air or on paper recalled better than those who drew them on paper in both experiments, suggesting that the facilitation effect of co-thought gesture holds for both verbal and nonverbal recall modalities. It is possibly because, co-thought gesture, as a kind of representational action, consolidates spatial sequence better than drawing and thus exerting more powerful influence on spatial representation. PMID:25426624

  19. Perception bias in route choice

    NARCIS (Netherlands)

    Vreeswijk, J.D.; Thomas, T.; Berkum, van E.C.; Arem, van B.

    2014-01-01

    Travel time is probably one of the most studied attributes in route choice. Recently, perception of travel time received more attention as several studies have shown its importance in explaining route choice behavior. In particular, travel time estimates by travelers appear to be biased against non-

  20. Spiral-CT assisted detection and quantification of pulmonary reaction in breast cancer patients treated with cobalt- or linac megavoltage radiation therapy

    International Nuclear Information System (INIS)

    Object : The aim of the study is to sensitively detect and quantify the irradiation induced pulmonary side effects in breast cancer patients, using the quantitative spiral-CT analysis. Material and Method : We prospectively investigated 48 patients at an average of 62 yrs. on pulmonary reactions after postopera-tive radiotherapy on mamma carcinoma. The patients were treated with either tangential thoracic fields alone (26 pat) or tangents with additional opposing ap/pa-fields to the supraclavicular(sc) and axillary(ax) region(18 pat) or tangents and sc-ax-fields with an additional parasternal or dorsal field(4 pat). 44 patients underwent irradiation at the 1MV cobalt with 50Gy, while 4 patients were irradiated at the 6MV linac with 50Gy. Quantitative spiral chest-CT was performed before radiotherapy and six(6), respectively twelve(12) weeks after therapy. Using the 'region of interest (RoI)' technique, the peripheral, subpleural and apical lung parenchyma on corresponding slices of the pretherapeutic- and the follow-up chest-CT's was examined according to its' density and volume changes. Especially, the quantitative spiral-CT marks an distinct advantage, allowing the complete reception of the examined lung volume without skipping a slice because of patient's breathing. Results : While the lung regions, within the treatment volume of the tangents showed an average density increase of 10% ±6% at 6 weeks, respectively of 15% ±8% at 12 weeks after radiotherapy, there was only a minor increase at the apical parenchyma, irradiated with the sc-ax fields of 7% ±4%, respectively 10% ±5%. Two patients, receiving a parasternal field demonstrated a sharp density gain of 24% ±7% and 29% ±8%. There were no clinical symptoms suggesting a radiation pneumonitis. An age related density increase could be observed, revealing a gain of 12% ±7% in those patients older than 60 yrs (28pat), while in the younger group (20pat) the rise was 8% ±5%. Regarding the functional lung

  1. Generalized Maneuvers in Route Planning

    CERN Document Server

    Hlineny, Petr

    2011-01-01

    We study an important practical aspect of the route planning problem in real-world road networks -- maneuvers. Informally, maneuvers are walks that might either decrease or increase the weight of a route by additional costs. One can model a wide range of route restrictions or traffic regulations by maneuvers. For instance turn-prohibitions, traffic light delays, round-abouts, forbidden passages and so on. A new approach to tackle maneuvers during route planning queries without prior adjustments of the underlying road network graph is presented. First, a generic maneuver is defined so that we are able to model almost arbitrarily complex route restriction. In the rest we show how to modify Dijkstra's algorithm to respect maneuvers together with a formal proof of correctness and a complexity analysis of our algorithm.

  2. Security Consideration With Dynamic Routing

    Directory of Open Access Journals (Sweden)

    VISWESWARARAO BOLLA

    2012-03-01

    Full Text Available One of the major issues for data communication over wired and wireless networks is the security. the past work is on the designs of cryptography algorithms and system infrastructures. Dynamic routing algorithm called improved dynamic routing with security consideration, which is based on the concept of Zone Routing Protocol (ZRP that could randomize delivery paths for data transmission. The algorithm is easy to implement and compatible with popular routing protocols, such as the Routing Information Protocol (RIP in wired networks and Destination-Sequenced Distance Vector (DSDV protocol in wireless networks, without introducing extra control messages. This algorithm is mainly proposed to improve the and to overcome the limitations existing with the present cryptographic algorithms and protocols. Although some designs like IP security, Secure Socket Layer provide essential security, E-Mail security they unavoidably introduce substantial overheads in the Gateway/Host performance and effective network bandwidths.

  3. Ultrasonication-assisted ultrafast preparation of multiwalled carbon nanotubes/Au/Co3O4 tubular hybrids as superior anode materials for oxygen evolution reaction

    Science.gov (United States)

    Fang, Yiyun; Li, Xinzhe; Hu, Yiping; Li, Feng; Lin, Xiaoqing; Tian, Min; An, Xingcai; Fu, Yan; Jin, Jun; Ma, Jiantai

    2015-12-01

    Efficient and simple operation electrocatalysts for the oxygen evolution reaction (OER) are essential components of renewable energy technologies. Here, a novel, simple, and efficient routine is presented for the first time by constructing a high-efficiency anode catalyst for OER. With the aid of high intensity ultrasound, a uniformly loading, conductive multiwalled carbon nanotubes/metal/transition metal-oxide (CNTs-Au@Co3O4) tubular hybrids is synthesized. In alkaline media, the materials catalyze OER with an onset potential of 1.56 V vs. reversible hydrogen electrode (RHE) and overpotential only of 350 mV to achieve a stable current density of 10 mA cm-2 for at least 25 h. The unusual catalytic activity and stability is due to the following elements. Firstly, the tubular architecture not only provides sufficient active centers for OER, but also improves rapid mass/charge transport. Secondly, Co3O4 layer protects Au nanoparticles (NPs) against detachment. In addition, we also prove that the highest electronegativity metal Au accelerate the formation of catalytic active sites of CoIV species for OER. It is believed that this simple preparation method paves a way to fabricate a range of CNTs/metal/metal-oxide based composites as superior OER catalysts.

  4. Surgical Assisting

    Science.gov (United States)

    ... specific training over and above a degree in science, nursing, physician assisting, or another health profession. Prerequisites . Recommended eligibility requirements for admission into a surgical assisting program are: Bachelor of Science degree (or higher) Associate degree in an allied ...

  5. Assistive Technology

    Science.gov (United States)

    ... Page Resize Text Printer Friendly Online Chat Assistive Technology Assistive technology (AT) is any service or tool that helps ... be difficult or impossible. For older adults, such technology may be a walker to improve mobility or ...

  6. Assisted Living

    Science.gov (United States)

    ... overwhelming majority of residents are female. Assisted Living Philosophy The philosophy of assisted living is to provide personalized, resident ... loved ones to learn about the care provider philosophy . Freedom of Choice The most progressive state regulations ...

  7. Preparation of Nd-doped barium cerate through different routes

    DEFF Research Database (Denmark)

    Chen, F.L.; Toft Sørensen, O.; Meng, G.Y.; Peng, D.K.

    1997-01-01

    BaCe0.9Nd0.1O3-delta was prepared through different routes: oxalate coprecipitation (OF), carbonate-oxide mixed by ball-milling (COB) and carbonate-oxide mixed by mortar/pestle (COM). The reaction process studied by DTA-TG and XRD showed that calcination of the precursor powders at T greater than...

  8. Production of phosphorous-containing oleochemicals through an epoxide route

    Science.gov (United States)

    Phosphorous was incorporated into the middle of the fatty chain on a methyl ester utilizing an epoxide route. Methyl oleate was epoxidized and then a catalyzed or uncatalyzed ring opening reaction was performed using dibutyl phosphate in order to synthesize a butyl dioxaphospholane-containing deriv...

  9. Vehicle Routing With User Generated Trajectory Data

    DEFF Research Database (Denmark)

    Ceikute, Vaida; Jensen, Christian S.

    shortest nor fastest, indicating that drivers value route properties that are diverse and hard to quantify or even identify. We propose a routing service that uses an existing routing service while exploiting the availability of historical route usage data from local drivers. Given a source and destination......, the service recommends a corresponding route that is most preferred by local drivers. It uses a route preference function that takes into account the number of distinct drivers and the number of trips associated with a route, as well as temporal aspects of the trips. The paper provides empirical...... studies with real route usage data and an existing online routing service....

  10. Reaction mechanism of core–shell MoO2/MoS2 nanoflakes via plasma-assisted sulfurization of MoO3

    Science.gov (United States)

    Kumar, Prabhat; Singh, Megha; Sharma, Rabindar K.; Reddy, G. B.

    2016-05-01

    The sulfurization of MoO3 in an H2S/Ar plasma atmosphere has been experimentally studied and a reaction mechanism has been proposed based on the results obtained. Nanostructured thin films (NTFs) of MoO3 were sulfurized at different temperatures varying from 150 °C to 550 °C. High-resolution transmission electron microscopy (TEM) images depict core–shell nanoflakes with varying shell thicknesses as the sulfurization temperature (T sn) is varied. The shells consist of MoS2 and the core is MoO2/MoO3. X-ray diffraction (XRD) and Raman analysis have been used to study the structural changes as MoO3 is sulfurized. The analyses showed two phases, MoO2 and MoS2, at low temperatures (≤350 °C), whereas the films sulfurized at higher temperatures show predominantly MoS2. The scanning electron microscopy (SEM) results show no noticeable changes in the surface morphology of the NTFs after sulfurization. X-ray photoelectron spectroscopy (XPS) was carried out to calculate the relative percentages of MoO3, MoO2 and MoS2. It is revealed that sulfurization of MoO3 in the plasma is affected by T sn. The sulfurization process occurs in two steps, involving the reduction of MoO3 to form MoO2 in the first step, followed by MoO2 being converted into MoS2. It is also evident that the reduction of MoO3 is more a result of the reactive species of hydrogen (H*) than the replacement of oxygen by sulfur in the second step.

  11. Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

    International Nuclear Information System (INIS)

    Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV–vis (UV–vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

  12. Road Routes for Waste Disposal - MDC_RecyclingRoute

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This CURBSIDE RECYCLING ROUTES BOUNDARIES LAYER IS A polygon feature class created for the Miami-Dade Department of Solid Waste Management (DSWM). It contains the...

  13. Critical Route Network for Earthquake Response and Dynamic Route Analysis

    OpenAIRE

    Peeta, Srinivas; Kalafatas, Georgios

    2007-01-01

    Earthquakes can significantly disrupt societal functioning, cause ecological damage, and lead to loss of human lives and property, warranting a coordinated and efficient response to mitigate their negative impacts. Preparedness against earthquakes entails a pre-disaster planning aspect and a post disaster operational aspect. In the JTRP study “Emergency Earthquake Routes for the State of Indiana; Part I: Criteria for Selection of Primary Routes: Transportation Aspects”, a multicommodity maxim...

  14. Capacity Constrained Routing Algorithms for Evacuation Route Planning

    OpenAIRE

    Shekhar, Shashi; George, Betsy; Lu, Qingsong

    2010-01-01

    Efficient tools are needed to identify routes and schedules to evacuate affected populations to safety in face of natural disasters or terrorist attacks. Challenges arise due to violation of key assumptions (e.g. stationary ranking of alternative routes, Wardrop equilibrium) behind popular shortest path algorithms (e.g. Dijktra's, A*) and microscopic traffic simulators (e.g. DYNASMART). Time-expanded graphs (TEG) based mathematical programming paradigm does not scale up to large urban scenari...

  15. Protocol Independent Adaptive Route Update for VANET

    OpenAIRE

    Asim Rasheed; Sana Ajmal; Amir Qayyum

    2014-01-01

    High relative node velocity and high active node density have presented challenges to existing routing approaches within highly scaled ad hoc wireless networks, such as Vehicular Ad hoc Networks (VANET). Efficient routing requires finding optimum route with minimum delay, updating it on availability of a better one, and repairing it on link breakages. Current routing protocols are generally focused on finding and maintaining an efficient route, with very less emphasis on route update. Adaptiv...

  16. Thermoluminescent dosimetric comparison for two different MgB4O7:Dy production routes

    International Nuclear Information System (INIS)

    There are several routes employed for the production of synthetic magnesium tetraborate, for example, sol–gel method, combustion, wet reaction synthesis, solid-state route and precipitation (crystal growth). The most commonly used synthesis methods are the wet reaction (precipitation) and solid-state synthesis; both production routes are efficient, but is very difficult to find a direct comparison for them. The present work proposes a direct comparison of both production routes used for magnesium tetraborate synthesis for thermoluminescent (TL) dosimetry. In this work, MgB4O7:Dy was prepared by both methods, wet reaction or precipitation-route 1, and solid-state synthesis -route 2, with the same amount of dopant (0.1%). In the first part of work, the crystalline phases were confirmed by X-ray diffraction (XRD) and it was observed that MgB4O7:Dy can be obtained satisfactorily through both routes, although a very intense crystalline phase of H3BO3 for the powder produced through route 1 was observed. The dose response curve of MgB4O7 pellets (produced for both routes) presents linear behavior when the materials are irradiated with 60Co in the dose range of 10–100 Gy. The results showed that both methods produce MgB4O7:Dy efficiently; however, solid-state synthesis produces MgB4O7:Dy more sensitive to gamma radiation. - Highlights: • High doses dosimetry with MgB4O7:Dy. • Some differences about two different routes of MgB4O7:Dy. • Wet reaction and solid state synthesis routes for MgB4O7:Dy production. • The MgB4O7:Dy pellets produced by solid state present some advantages

  17. Minimum energy reaction profiles for ATP hydrolysis in myosin.

    Science.gov (United States)

    Grigorenko, Bella L; Kaliman, Ilya A; Nemukhin, Alexander V

    2011-11-01

    The minimum energy reaction profiles corresponding to two possible reaction mechanisms of adenosine triphosphate (ATP) hydrolysis in myosin are computed in this work within the framework of the quantum mechanics-molecular mechanics (QM/MM) method by using the same partitioning of the model system to the QM and MM parts and the same computational protocol. On the first reaction route, one water molecule performs nucleophilic attack at the phosphorus center P(γ) from ATP while the second water molecule in the closed protein cleft serves as a catalytic base assisted by the Glu residue from the myosin salt bridge. According to the present QM/MM calculations consistent with the results of kinetic studies this reaction pathway is characterized by a low activation energy barrier about 10 kcal/mol. The computed activation energy barrier for the second mechanism, which assumes the penta-coordinated oxyphosphorane transition state upon involvement of single water molecule in the reaction, is considerably higher than that for the two-water mechanism. PMID:21839658

  18. Phosphate valorization by dry chlorination route

    Directory of Open Access Journals (Sweden)

    Kanari N.

    2016-01-01

    Full Text Available This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca2P2O7, is subjected to reactions with Cl2+CO+N2 and Cl2+C+N2 at temperatures ranging from 625 to 950°C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM and XRD examinations of the chlorinated residues allowed the interpretation of phenomena and reactions mechanism occurring during the calcium pyrophosphate carbochlorination. Reaction rate of Ca2P2O7 by Cl2+CO+N2 at 950°C is slowed down due to the formation of a CaCl2 liquid layer acting as a barrier for the diffusion of the reactive gases and further reaction progress. While, the carbochlorination with Cl2+C+N2 led to almost full chlorination of Ca2P2O7 at 750°C and the process proceeds with an apparent activation energy of about 104 kJ/mol between 625 and 750°C. Carbochlorination technique can be considered as an alternative and selective route for the valorization of low grade phosphates and for the phosphorus extraction from its bearing materials.

  19. An attempt to explore the production routes of Astatine radionuclides: Theoretical approach

    OpenAIRE

    Maiti, Moumita; Lahiri, Susanta

    2008-01-01

    In order to fulfil the recent thrust of Astatine radionuclides in the field of nuclear medicine various production routes have been explored in the present work. The possible production routes of $^{209-211}$At comprise both light and heavy ion induced reactions at the bombarding energy range starting from threshold to maximum 100 MeV energy. For this purpose, we have used the nuclear reaction model codes TALYS, ALICE91 and PACE-II. Excitation functions of those radionuclides, produced throug...

  20. New TPG bus route 28

    CERN Multimedia

    2003-01-01

    Geneva's Public Transport services (TPG) have recently inaugurated a new bus line 28, connecting the La Tour Hospital in Meyrin to the international organisations in Geneva, via the airport. All signs associated with this route will be yellow in colour. Timetables and route details can be found at http://www.tpg.ch. Relations with the Host States Service http://www.cern.ch/relations/ Tel. 72848

  1. Template-free polyoxometalate-assisted synthesis for ZnO hollow spheres

    International Nuclear Information System (INIS)

    ZnO hollow spheres with diameters ranging from 400 to 600 nm and the thickness of shell approximate 80 nm were synthesized by a simple polyoxometalate-assisted solvothermal route without using any templates. The effect of polyoxometalate concentration, reaction time and temperature on the formation of the hollow spheres was investigated. The results indicated that the hollow spheres were composed of porous shells with nanoparticles and polyoxometalate play a key role in controlling morphology of ZnO. A possible growth mechanism based on polyoxometalate-assisted assembly and slow Ostwald ripening dissolution in ethanol solution is tentatively proposed. In addition, the room temperature photoluminescence spectrum showed that the ZnO hollow spheres exhibit exciting emission features with wide band covering nearly all the visible region. - Graphical abstract: ZnO hollow spheres with porous shell were synthesized by a one-step polyoxometalate-assisted solvothermal route at low temperature. Room temperature photoluminescence spectrum of the ZnO hollow spheres exhibits exciting emission features with a broad band covering nearly all the visible region.

  2. A Novel Route to Prepare Nanocomposites in Larger Scale

    Institute of Scientific and Technical Information of China (English)

    Wei WU; Lailong LUO; Guangwen CHU; Shengjun BAI; Haikui ZOU; Jianfeng CHEN

    2007-01-01

    A novel route to prepare nanocomposites was illustrated through preparing overbased calcium petroleum sulfonate lubricating oil detergent, where the rotating packed bed (RPB) was used as reactor in place of conventional reaction vessel. The results showed that the carbonation efficiency is improved, the raw materials consumption is reduced, and the dispersibilities, sizes and morphologies of nano-sized CaCO3 particles in overbased detergent are enhanced. It is deduced reasonably that this route can be extensively applied to nanocomposites preparation in appropriate conditions and would be a platform technology in this field.

  3. A new combustion route to -Fe2O3 synthesis

    Indian Academy of Sciences (India)

    A Venkataraman; Vijay A Hiremath; S K Date; S D Kulkarni

    2001-12-01

    A new combustion route for the synthesis of -Fe2O3 is reported by employing purified -Fe2O3 as aprecursor in the present investigation. This synthesis which is similar to a self propagation combustion reaction, involves fewer steps, a shorter overall processing time, is a low energy reaction without the need of any explosives, and also the reaction is completed in a single step yielding magnetic iron oxide i.e. -Fe2O3. The as synthesized -Fe2O3 is characterized employing thermal, XRD, SEM, magnetic hysteresis, and density measurements. The effect of ball-milling on magnetic properties is also presented.

  4. Synthesis and photoluminescence properties of single-crystal ZnO hexagonal pyramids by PEG400-assisted thermal decomposition route%单晶ZnO六棱锥的PEG400辅助热分解合成及其光致发光性能

    Institute of Scientific and Technical Information of China (English)

    刘劲松; 张朔; 李子全; 朱孔军; 陈建康; 裘进浩; 王春花; 高雪琴; 王莉萍

    2012-01-01

    将由Zn(CH3COO)2·2H2O和Na2CO3通过室温研磨反应获得的前驱体在PEG400存在下于240℃热分解获得大量的ZnO六棱锥产物.用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)表征产物的晶体结构和形貌.进步的实验结果表明:PEG400在ZnO六棱锥形成过程中发挥着重要作用,单六棱锥和双六棱锥的结构差异来自于热分解反应.光致发光谱(PL)测试表明:ZnO六棱锥在386 nm处展示强的近带隙发射,在550 nm处展示较弱的绿光发射.435 cm-1处的拉曼振动表明ZnO六棱锥具有良好的晶体质量.%Large-scale synthesis of ZnO hexagonal pyramids was achieved by a simple thermal decomposition route of precursor at 240 ℃ in the presence of PEG400.The precursor was obtained by room-temperature solid-state grinding reaction between Zn(CH3COO)2·2H2O and Na2CO3· Crystal structure and morphology of the products were analyzed and characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM).The results of further experiments show that PEG400 has an important role in the formation of ZnO hexagonal pyramids.Difference between the single and double hexagonal pyramid structure may come from the special thermal decomposition reaction.The photoluminescence (PL) spectra of ZnO hexagonal pyramids exhibit strong near-band-edge emission at about 386 nm and weak green emission at about 550 nm.The Raman-active vibration at about 435 cm-1 suggests that the ZnO hexagonal pyramids have high crystallinity.

  5. How a structured vibrational environment controls the performance of a photosystem II reaction centre-based photocell

    CERN Document Server

    Stones, Richard; van Grondelle, Rienk; Olaya-Castro, Alexandra

    2016-01-01

    Photosynthetic reaction centres are pigment-protein complexes that can transform photo-induced electronic excitations into stable charge separated states with near-unit quantum efficiency. Here we consider a theoretical photovoltaic device that places a single photosystem II reaction centre between electrodes to investigate how the mean photo-current and its fluctuations depend on the vibrational environment that assists energy and electron transfer. Our results indicate that selective coupling to well resolved vibrational modes does not necessarily offer an advantage in terms of power output but does lead to photo-currents with suppressed noise levels. The exciton manifold and the structured vibrations assisting electron transfer can also support the emergence of a phenomenon akin to dynamical channel blockade, whereby excitonic traps can impose competing routes for population transfer under steady state operation. Our results help characterizing the device-like functionality of these complexes for their pot...

  6. Protocol independent adaptive route update for VANET.

    Science.gov (United States)

    Rasheed, Asim; Ajmal, Sana; Qayyum, Amir

    2014-01-01

    High relative node velocity and high active node density have presented challenges to existing routing approaches within highly scaled ad hoc wireless networks, such as Vehicular Ad hoc Networks (VANET). Efficient routing requires finding optimum route with minimum delay, updating it on availability of a better one, and repairing it on link breakages. Current routing protocols are generally focused on finding and maintaining an efficient route, with very less emphasis on route update. Adaptive route update usually becomes impractical for dense networks due to large routing overheads. This paper presents an adaptive route update approach which can provide solution for any baseline routing protocol. The proposed adaptation eliminates the classification of reactive and proactive by categorizing them as logical conditions to find and update the route. PMID:24723807

  7. Dynamic routing using maximal road capacity

    NARCIS (Netherlands)

    Rothkrantz, L.J.M.

    2015-01-01

    Current routing devices route an individual car driver from start to destination in the shortest time. In this paper we propose a routing algorithm, routing the whole population of car drivers in the shortest time. The algorithm is an adapted dynamic version of the shortest path algorithm of Dijkstr

  8. Compressed Transmission of Route Descriptions

    CERN Document Server

    Batz, Gernot Veit; Luxen, Dennis; Sanders, Peter

    2010-01-01

    We present two methods to compress the description of a route in a road network, i.e., of a path in a directed graph. The first method represents a path by a sequence of via edges. The subpaths between the via edges have to be unique shortest paths. Instead of via edges also via nodes can be used, though this requires some simple preprocessing. The second method uses contraction hierarchies to replace subpaths of the original path by shortcuts. The two methods can be combined with each other. Also, we propose the application to mobile server based routing: We compute the route on a server which has access to the latest information about congestions for example. Then we transmit the computed route to the car using some mobile radio communication. There, we apply the compression to save costs and transmission time. If the compression works well, we can transmit routes even when the bandwidth is low. Although we have not evaluated our ideas with realistic data yet, they are quite promising.

  9. Atmospheric Pressure Microwave Assisted Heterogeneous Catalytic Reactions

    Directory of Open Access Journals (Sweden)

    Ken Belmore

    2007-07-01

    Full Text Available The newly synthesized 5,10,15,20-tetra[3-(3-trifluoromethylphenoxy]porphyrin, TTFMPP, has been characterized using mass spectroscopy, 1H-, 13C- and 19F-NMR, MALDI-TOF mass spectrometry, UV-Vis and fluorescence spectrophotometry, andcyclic voltammetry. The NMR confirmed the structure of the compound and the massspectrum was in agreement with the proposed molecular formula. The UV-Vis absorptionspectrum of TTFMPP shows characteristic spectral patterns similar to those of tetraphenylporphryin, with a Soret band at 419 nm and four Q bands at 515, 550, 590, and 648 nm.Protonation of the porphyrin with TFA resulted in the expected red shift of the Soret band.Excitation at 419 nm gave an emission at 650 nm. The quantum yield of the porphyrin wasdetermined to be 0.08. Cyclic voltammetry was used to determine the oxidation andreduction potentials of the new porphyrin. Two quasi-reversible one-electron reductions at–1.00 and –1.32 V and a quasi-reversible oxidation at 1.20 V versus the silver/silverchloride reference electrode with tetrabutylammonium tetrafluoroborate as the supportingelectrolyte in methylene chloride were observed.

  10. ACO based routing for MANETs

    CERN Document Server

    Arif, Mohammad

    2012-01-01

    Mobile ad hoc network (MANET) is a collection of wireless mobile nodes. It dynamically forms a temporary network without using any pre existing network infrastructure or centralized administration i.e. with minimal prior planning. All nodes have routing capabilities and forward data packets to other nodes in multi-hop fashion. As the network is dynamic, the network topology continuously experiences alterations during deployment. The biggest challenge in MANETs is to find a path between communicating nodes. The considerations of the MANET environment and the nature of the mobile nodes create further complications which results in the need to develop special routing algorithms to meet these challenges. Swarm intelligence, a bio-inspired technique, which has proven to be very adaptable in other problem domains, has been applied to the MANET routing problem as it forms a good fit to the problem. In ant societies the activities of the individuals are not regulated by any explicit form of centralized control but ar...

  11. Soft chemical routes to semiconductor nanostructures

    Indian Academy of Sciences (India)

    Ujjal K Gautam; Kripsindhu Sardar; F L Deepak; C N R Rao

    2005-10-01

    Soft chemistry has emerged as an important means of generating nanocrystals, nanowires and other nanostructures of semiconducting materials. We describe the synthesis of CdS and other metal chalcogenide nanocrystals by a solvothermal route. We also describe the synthesis of nanocrystals of AlN, GaN and InN by the reaction of hexamethyldisilazane with the corresponding metal chloride or metal cupferronate under solvothermal conditions. Nanowires of Se and Te have been obtained by a self-seeding solution-based method. A single source precursor based on urea complexes of metal chlorides gives rise to metal nitride nanocrystals, nanowires and nanotubes. The liquid-liquid interface provides an excellent medium for preparing single-crystalline films of metal chalcogenides.

  12. Routing Discovery Algorithm Using Parallel Chase Packet

    Directory of Open Access Journals (Sweden)

    Amera Al-Ameri

    2013-04-01

    Full Text Available On demand routing protocols for ad hoc networks such as Ad Hoc On Demand Distance Vector (AODV initiate a route discovery process when a route is needed by flooding the network with a route request packet. The route discovery process in such protocols depends on a simple flooding as a broadcast technique due to its simplicity. Simple flooding results in packet congestion, route request overhead and excessive collisions, namely broadcast storm problem. A number of routing techniques have been proposed to control the simple flooding technique. Ideally, the broadcast of route request or the route discovery process must be stopped as soon as the destination node is found. This will free the network from many redundant packets that may cause network collision and contention. In this paper, chasing packet technique is used with standard AODV routing protocol to end the fulfilled route requests. The chase packet is initiated by the source node and is broadcasted in parallel with route request packet. As soon as the destination is found the chase packet starts its work by trying to catch and discard the route request in early stages before it broadcasts further in the network. Performance evaluation is conducted using simulation to investigate the performance of the proposed scheme against the existing approach that uses chase packet technique such as Traffic Locality Route Discovery Algorithm with Chase (TLRDA-C. Results reveal that the proposed scheme minimizes end-to-end packet delays and achieves low routing request overhead.

  13. Optimal routing of electric vehicles

    OpenAIRE

    Andelmin, Juho

    2014-01-01

    In this thesis, a vehicle routing problem (VRP) variant tailored for plug-in battery electric vehicles (BEVs) is studied. The studied problem involves a fleet of identical BEVs located at a central depot, a set of customers that must be serviced within given time windows, and a set of charging stations where the vehicles can recharge their batteries. The objective is to design a set of vehicle routes, each starting and ending at the depot, so that each customer is serviced exactly once and th...

  14. Synthesis of New Pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (PCU) Cyanosilylated Derivatives Using Sulphated Zirconia and Hydrotalcite as Catalysts in Microwave-Assisted Reactions under Solvent Free Conditions

    OpenAIRE

    Juan Navarrete-Bolaños; Rubén Gaviño-Ramírez; Eduardo González-Zamora; Leticia Lomas-Romero; Guillermo E. Negrón-Silva; Deyanira Angeles-Beltrán; Laura Nadxieli Palacios-Grijalva; Nahí Adriana Guerra-Navarro

    2011-01-01

    A comparison was made of the effectiveness of the functionalization reactions of pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (PCU) using sulphated zirconia in protection-deprotection reactions and Mg/Al hydrotalcite in a cyanosilylation reaction, under classical thermal conditions and imposing microwave radiation; improved yields and reaction times were considered.

  15. Synthesis of New Pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (PCU Cyanosilylated Derivatives Using Sulphated Zirconia and Hydrotalcite as Catalysts in Microwave-Assisted Reactions under Solvent Free Conditions

    Directory of Open Access Journals (Sweden)

    Juan Navarrete-Bolaños

    2011-08-01

    Full Text Available A comparison was made of the effectiveness of the functionalization reactions of pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (PCU using sulphated zirconia in protection-deprotection reactions and Mg/Al hydrotalcite in a cyanosilylation reaction, under classical thermal conditions and imposing microwave radiation; improved yields and reaction times were considered.

  16. Dynamic Weather Routes Architecture Overview

    Science.gov (United States)

    Eslami, Hassan; Eshow, Michelle

    2014-01-01

    Dynamic Weather Routes Architecture Overview, presents the high level software architecture of DWR, based on the CTAS software framework and the Direct-To automation tool. The document also covers external and internal data flows, required dataset, changes to the Direct-To software for DWR, collection of software statistics, and the code structure.

  17. ACO Based Routing for MANETs

    Directory of Open Access Journals (Sweden)

    Mohammad Arif

    2012-05-01

    Full Text Available Mobile ad hoc network (MANET is a collection of wireless mobile nodes. It dynamically forms atemporary network without using any pre existing network infrastructure or centralized administrationi.e. with minimal prior planning. All nodes have routing capabilities and forward data packets to othernodes in multi-hop fashion. As the network is dynamic, the network topology continuously experiencesalterations during deployment. The biggest challenge in MANETs is to find a path betweencommunicating nodes. The considerations of the MANET environment and the nature of the mobile nodescreate further complications which results in the need to develop special routing algorithms to meet thesechallenges. Swarm intelligence, a bio-inspired technique, which has proven to be very adaptable in otherproblem domains, has been applied to the MANET routing problem as it forms a good fit to the problem.In ant societies the activities of the individuals are not regulated by any explicit form of centralizedcontrol but are the result of self-organizing dynamics driven by local interactions and communicationsamong a number of relatively simple individuals. This unique characteristic has made ant societies anattractive and inspiring model for building new algorithms and new multi-agent systems. In this paper,we have studied and reviewed Ant Colony based routing algorithms and its variants. Finally, aperformance evaluation of the original ARA and the EARA is carried out with respect to each other.

  18. Assisted Ventilation.

    Science.gov (United States)

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear. PMID:25501776

  19. Synthesis of Nano Crystalline MgAl2O4Spinel Powder by Microwave Assisted Combustion%Synthesis of Nano Crystalline MgAl2O4 Spinel Powder by Microwave Assisted Combustion

    Institute of Scientific and Technical Information of China (English)

    Leila Torkian; Mostafa M Amini; Zohreh Bahrami

    2011-01-01

    Stoichiometric MgAl2O4 spinel nanoparticles were synthesized by microwave assisted combustion reaction from aluminium nitrate nanohydrate (Al(NO3)3.9H2O) and Sol-Gel prepared magnesium hydroxide (Mg(OH)2) in the presence of urea ((NH2)2CO) as a fuel, in about 20 min of irradiation. X-ray diffraction (XRD) studies reveal that microwave assisted combustion synthesis route yields single-phase spinel nanoparticles with larger crystalline size (around 75 nm) than other conventional heating methods. Scanning electronic microscope (SEM) images show nanoparticles with spherical shape and homogenous morphology. The surface area measurements (SBET) show crystals with 2.11 m2/g and 0.0033 mL/g pore volume.

  20. An embedded route finder and tracing system for a stepped robot

    Science.gov (United States)

    Wang, Xiangjun; Li, Zhi; Zhou, Xinling

    2003-09-01

    The paper presents a new embedded sensor method of non-contact automatic route-finding and route-tracing for stepped robot. The final system is designed and integrated into a single hardware PCB with size of 30x30x15 mm3. A line scanning charge couple device (CCD) with 1024 pixels is used to obtain the plane scene of route, and a pair of infrared LED is employed to provide the illumination of the route-finder. Moreover, this route-finder still includes a micro lens, CCD driver, instrumentation pre-amplifier, edge extracting circuit, FPGA circuit for position measure and logic control, direction and state display of the route-finder by LED, moving direction control pins output and power manage circuits. The router-finder for stepped robot has the advantages of simple and fast operation, easy assembly with robot, small volume, high sensitivity and precision for route-finding and tracing. The paper outlines in detail the principle of the route-finding and tracing by edge extraction and edge position measure using a CCD image sensor with a micro lens assisted by infrared illumination and a FPGA circuit. Some relational edge extraction and measure algorithms suitable for embedded system with FPGA are introduced in the paper too. Finally, the actual experiment results are given.

  1. Highway route controlled quantity shipment routing reports - An overview

    International Nuclear Information System (INIS)

    US Department of Transportation (DOT) regulations require a postnotification report from the shipper for all shipments of radioactive materials categorized as a Highway Route Controlled Quantity. These postnotification reports, filed in compliance with 49 CFR 172.203(d), have been compiled by the DOT in a database known as the Radioactive Materials Routing Report (RAMRT) since 1982. The data were sorted by each of its elements to establish historical records and trends of Highway Route Controlled Quantity shipments from 1982 through 1987. Approximately 1520 records in the RAMRT database were compiled for this analysis. Approximately half of the shipments reported for the study period were from the US Department of Energy (DOE) and its contractors, with the others being commercial movements. Two DOE installations, EG and G Idaho and Oak Ridge, accounted for nearly half of the DOE activities. Similarly, almost half of the commercial movements were reported by two vendors, Nuclear Assurance Corporation and Transnuclear, Incorporated. Spent fuel from power and research reactors accounted for approximately half of all shipments

  2. Route Scherrer and Route Einstein closed for construction work

    CERN Multimedia

    2015-01-01

    Please note that Route Scherrer will be inaccessible for two and a half months from the beginning of March and that part of Route Einstein will be closed for two weeks from the end of February.   Figure 1. The part of Route Scherrer between Building 510 and Building 53 (see Figure 1) will be closed from the beginning of March until mid-May for civil engineering works.   The superheated water pipes supplying the buildings in this area date back to 1959 and therefore present a significant risk of leakage. In order to ensure the reliable supply of superheated water, and, by extension, heating, to all premises near the Main Building (i.e. Buildings 500, 501, 503, 60, 62, 63 and 64), a new buried service duct will be installed between the basements of Buildings 53 and 61 to house a new superheated water pipe. Figure 2. The following car parks will, however, remain accessible for the duration of the works: the Cèdres car park, the car park for Buildings 4 and 5, and the ca...

  3. Comparison of on Demand Routing Protocols

    Directory of Open Access Journals (Sweden)

    Bharat Bhushan

    2013-02-01

    Full Text Available A routing protocol is used to facilitate communication in ad hoc network. The primary goal of such a routing protocol is to provide an efficient and reliable path between a pair of nodes. The routing protocols for ad hoc network can be categorized into three categories: table driven, on demand and hybrid routing. The table driven and hybrid routing strategies require periodic exchange of hello messages between nodes of the ad hoc network and thus have high processing and bandwidth requirements. On the other hand on demand routing strategy creates routes when required and hence is very much suitable for ad hoc network. This paper therefore examines the performance of three on demand routing protocols at application layer using QualNet-5.01 simulator.

  4. Hearing Assistive Technology

    Science.gov (United States)

    ... for the Public / Hearing and Balance Hearing Assistive Technology Hearing Assistive Technology: FM Systems | Infrared Systems | Induction ... Assistive Technology Systems Solutions What are hearing assistive technology systems (HATS)? Hearing assistive technology systems (HATS) are ...

  5. Vehicle routing and the value of postponement

    OpenAIRE

    Pang, G.; L Muyldermans

    2013-01-01

    We study capacitated vehicle routing problems (CVRPs) in which the client demands occur over time and the collector or distributor performing the service can decide when to visit the clients. It has been reported in the literature that postponement of collection (or delivery) services may decrease the overall routing cost or distance. We investigate this issue in greater detail and report on experiments in different routing settings to uncover the impact of postponement on routing efficiency....

  6. Algorithmic generation of railroad and highway routes

    Energy Technology Data Exchange (ETDEWEB)

    Low, J. T.; Bushnell, R. C.; Shannon, R.; Borsos, R.; Graham, J.; Sherry, R.

    1979-01-01

    A minimum-time algorithm can be used to generate realistic highway routes between specific origins and destinations. Minimizing distances on links will not produce realistic railroad routes if links bear any resemblance to physical trackage. There are also multiple routes between two points since each carrier has its own philosophy. This paper outlines a systematic method of preparing information such that a computer algorithm can generate realistic routes for single- or multiple-carrier movements.

  7. VANET Routing Protocols: Pros and Cons

    OpenAIRE

    Paul, Bijan; Ibrahim, Md.; Bikas, Md. Abu Naser

    2012-01-01

    VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Due to rapid topology changing and frequent disconnection makes it difficult to design an efficient routing protocol for routing data among vehicles, called V2V or vehicle to vehicle communication and vehicle to road side infrastructure, called V2I. The existing routing protocols for VANET are not efficient to meet every traffic scenarios. Thus design of an efficient routing protocol h...

  8. Thematic Routes - Tourist Destinations in Romania

    OpenAIRE

    Mihaela DINU; Adrian CIOACA

    2008-01-01

    Thematic routes have become greatly demanded ”fashionable” tourist destinations, in recent years. In many countries they gained popularity not only through their value as individual objectives, but also through their attraction, generated by the association of tourist objectives, in a larger region. The main purpose of this article is to analyze the main Romanian thematic routes, as part of the European routes, or as regional/local routes, specific on a national level, their actual condition ...

  9. Routing Data Authentication in Wireless Networks; TOPICAL

    International Nuclear Information System (INIS)

    In this paper, we discuss several specific threats directed at the routing data of an ad hoc network. We address security issues that arise from wrapping authentication mechanisms around ad hoc routing data. We show that this bolt-on approach to security may make certain attacks more difficult, but still leaves the network routing data vulnerable. We also show that under a certain adversarial model, most existing routing protocols cannot be secured with the aid of digital signatures

  10. Blind Alley Aware ACO Routing Algorithm

    Science.gov (United States)

    Yoshikawa, Masaya; Otani, Kazuo

    2010-10-01

    The routing problem is applied to various engineering fields. Many researchers study this problem. In this paper, we propose a new routing algorithm which is based on Ant Colony Optimization. The proposed algorithm introduces the tabu search mechanism to escape the blind alley. Thus, the proposed algorithm enables to find the shortest route, even if the map data contains the blind alley. Experiments using map data prove the effectiveness in comparison with Dijkstra algorithm which is the most popular conventional routing algorithm.

  11. Flow-Assisted Synthesis of [10]Cycloparaphenylene through Serial Microreactions under Mild Conditions.

    Science.gov (United States)

    Kim, Heejin; Lee, Hyune-Jea; Kim, Dong-Pyo

    2016-01-22

    Cycloparaphenylene (CPP) has been recognized as an attractive template for the bottom-up synthesis of carbon nanotubes with uniform diameter, and is important for the chemistry of graphitic as well as ring-shaped macromolecules. However, the reported routes from halogenated benzenes have suffered from low yields even under time- and labor-consuming multistep conditions. Herein we report a flow-assisted synthesis of [10]CPP in four steps under mild conditions. For the synthesis, a selective nucleophilic addition of the unprotected diketone without the double-added byproduct was achieved within 3 s in high yield. Subsequently, the obtained compound was reacted with dilithiated benzene at 25 °C to form a U-shaped precursor for CPP in a separate microreactor, which was finally dimerized and aromatized to obtain [10]CPP by a two-step in-flask reaction. Precise control of time and flow facilitated by the flow-assisted system enabled the development of an efficient synthetic route for [10]CPP. PMID:26661931

  12. A route towards immune protection

    OpenAIRE

    Groot Nibbelink, Milou

    2016-01-01

    This work describes a route towards an immune protective device for islet of Langerhans transplantation. We developed a protocol to use MIN6 β cells aggregates as pseudo-islets to overcome the donor shortage issue (chapter 3). In this thesis we explored two different immune protective strategies; a multibore hollow fiber and flat microwell membranes. In chapter 4 we investigated the possibility to use a commercial multibore hollow fiber. In this chapter we showed that we were capable to physi...

  13. Shortest Paths and Vehicle Routing

    OpenAIRE

    Petersen, Bjørn; Pisinger, David

    2011-01-01

    This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown.

  14. Cultural Routes and Intangible Heritage

    Directory of Open Access Journals (Sweden)

    Enza Zabbini

    2012-08-01

    Full Text Available The theoretical interpretation of thematic routes helps to predict the effects on the territories visited by cultured tourists who want to enrich their cultural and emotional baggage. After the analysis of some interpretations, this paper will examine how the practical implementation of an itinerary approved by the Council of Europe has evolved over the years. And it will also reflect on the practical results in the areas involved in that project. "The Hannibal Pathway ", the main overland walk on the "Phoenician Route - Cultural Route recognized by the Council of Europe" – represents a case of study that allows to reflect over the impact of cultural tourism based on immaterial heritage. In fact, in the areas where the battle of 21 June 217 BC took place, nothing tangible is left, except the landscape that has kept its conformation intact. In these areas, thanks to the foresight of the local governments in the last three decades, the landscape of the plain has been preserved. This makes possible today to propose an historical path precisely based on the landscape and on the new techniques for the valorization of the heritage. In the Tuoro plain it is possible to see the battlefields, thus retracing the various stages of the battle, supported by the Documentation Centre of the Capra Palace and virtual reconstructions of high technical quality.

  15. The Pyramidal Capacitated Vehicle Routing Problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

  16. Classification of Dynamic Vehicle Routing Systems

    DEFF Research Database (Denmark)

    Larsen, Allan; Madsen, Oli B.G.; Solomon, Marius M.

    2007-01-01

    classify dynamic vehicle routing systems. Methods for evaluation of the performance of algorithms that solve on-line routing problems are discussed and we list some of the most important issues to include in the system objective. Finally, we provide a three-echelon classification of dynamic vehicle routing...... systems based on their degree of dynamism and the system objective....

  17. The pyramidal capacitated vehicle routing problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    2010-01-01

    This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

  18. Light Routing Algorithm for Utility Networks

    Directory of Open Access Journals (Sweden)

    Rosario Culmone

    2014-06-01

    Full Text Available In several application domains like Ambient Assisted Living systems or in users accounting services, specific network protocols are called for to interconnect different data processing devices having limited processing power and energy [1]. Typically, the interconnections are accomplished through dedicated cables or as power lines, or through wireless, but even if the cables are fully utilized, few protocols have been drawn up or planned to optimize communication among a high number of devices. One reason for the limited development of these protocols lies in the difficulty of reconciling the efficiency and efficacy of a protocol with scarce power computing of the nodes. This article will propose an efficient algorithm for routing applicable to networks with many nodes and with interferences typically present in power lines, and with low management overhead. The algorithm guarantees reliability and transparent distribution over large networks like accounting networks for the distribution of water, gas and tele-heating. Implementation of the protocol can be realized within the European M-Bus [EN13757] [2] [3]. 

  19. Sustainability Assessment of Chemical Processes: Evaluation of Three Synthesis Routes of DMC

    OpenAIRE

    Paula Saavalainen; Satish Kabra; Esa Turpeinen; Kati Oravisjärvi; Ganapati D. Yadav; Riitta L. Keiski; Eva Pongrácz

    2015-01-01

    This paper suggested multicriteria based evaluation tool to assess the sustainability of three different reaction routes to dimethyl carbonate: direct synthesis from carbon dioxide and methanol, transesterification of methanol and propylene carbonate, and oxidative carbonylation of methanol. The first two routes are CO2-based and in a research and development phase, whereas the last one is a commercial process. The set of environmental, social, and economic indicators selected were renewabili...

  20. Assessment of the synthesis routes conditions for obtaining ammonium dinitramide by the FT-IR

    OpenAIRE

    José Irineu Sampaio de Oliveira; Márcio Yuji Nagamachi; Milton Faria Diniz; Elizabeth da Costa Mattos; Rita de Cássia Lazzarini Dutra

    2011-01-01

    Over the last two decades, many routes have been proposed to synthesize ammonium dinitramide (ADN). However, most of them lie in routes in which reactants are too expensive for large-scale production. In this sense, the use of ordinary reactants is of paramount importance in this case. The aim in this synthesis consists on nitrating a starting reactant in a reaction known as nitration. Both the nitrating agent and the starting reactant should preferably be ordinary, narrowing the possibility ...

  1. Metaheuristics applied to vehicle routing. A case study. Part 3: Genetic Clustering and Tabu Routing

    Directory of Open Access Journals (Sweden)

    Guillermo González Vargas

    2010-04-01

    Full Text Available This paper presents hybrid meta-heuristics called Genetic Clustering and Tabu Routing for solving a vehicle routing problem using two phases methodology: first clustering and then routing. The results are compared with those obtained using meta-heuristics and heuristic techniques presented in previous papers. Genetic clustering and Tabu routing average results were 23% and 9.1% better, respectively.

  2. 29 CFR Appendix to Subpart E of... - Exit Routes, Emergency Action Plans, and Fire Prevention Plans

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Exit Routes, Emergency Action Plans, and Fire Prevention..., and Fire Prevention Plans This appendix serves as a nonmandatory guideline to assist employers in.... Fire prevention housekeeping. The standard calls for the control of accumulations of flammable...

  3. n-Butanol derived from biochemical and chemical routes: A review

    Directory of Open Access Journals (Sweden)

    B. Ndaba

    2015-12-01

    Full Text Available Traditionally, bio-butanol is produced with the ABE (Acetone Butanol Ethanol process using Clostridium species to ferment sugars from biomass. However, the route is associated with some disadvantages such as low butanol yield and by-product formation (acetone and ethanol. On the other hand, butanol can be directly produced from ethanol through aldol condensation over metal oxides/ hydroxyapatite catalysts. This paper suggests that the chemical conversion route is more preferable than the ABE process, because the reaction proceeds more quickly compared to the fermentation route and fewer steps are required to get to the product.

  4. Functionalization of anthracene: A selective route to brominated 1,4-anthraquinones

    Directory of Open Access Journals (Sweden)

    Kiymet Berkil Akar

    2011-07-01

    Full Text Available Efficient and stereoselective syntheses are described for the preparation of 2,3,9,10-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydroanthracenes 7, 8 and the corresponding 1,4-diol 17 by silver ion-assisted solvolysis of hexabromotetrahydroanthracene 6. Base-promoted aromatization of 7 and 8 afforded synthetically valuable tribromo-1-methoxyanthracenes 10 and 11. The reaction of 17 with sodium methoxide generated tribromodihydroanthracene-1,4-diol 27, whose oxidation with PCC gave 2,9,10-tribromoanthracene-1,4-dione (28. Therefore a selective and efficient method was developed for the preparation of compound 28 starting from 9,10-dibromoanthracene (1, in a simple four-step process. Compounds 10 and 11, and diol 27 constitute key precursors for the preparation of functionalized substituted anthracene derivatives that are difficult to prepare by other routes. The studies also reveal the broad range of reactivity and selectivity of the stereoisomeric anthracene derivatives.

  5. Routing for wireless multi-hop networks

    CERN Document Server

    Hamid, Sherin Abdel; Takahara, Glen

    2013-01-01

    The focus of this brief is to identify what unifies and what distinguishes the routing functions in four wireless multi-hop network paradigms. The brief introduces a generic routing model that can be used as a foundation of wireless multi-hop routing protocol analysis and design. It demonstrates that such model can be adopted by any wireless multi-hop routing protocol. Also presented is a glimpse of the ideal wireless multi-hop routing protocol along with several open issues.

  6. Submarine Pipeline Routing Risk Quantitative Analysis

    Institute of Scientific and Technical Information of China (English)

    徐慧; 于莉; 胡云昌; 王金英

    2004-01-01

    A new method for submarine pipeline routing risk quantitative analysis was provided, and the study was developed from qualitative analysis to quantitative analysis.The characteristics of the potential risk of the submarine pipeline system were considered, and grey-mode identification theory was used. The study process was composed of three parts: establishing the indexes system of routing risk quantitative analysis, establishing the model of grey-mode identification for routing risk quantitative analysis, and establishing the standard of mode identification result. It is shown that this model can directly and concisely reflect the hazard degree of the routing through computing example, and prepares the routing selection for the future.

  7. Risk-minimal routes for emergency cars

    OpenAIRE

    Woelki, Marko; Nippold, Ronald; Bonert, Michael; Ruppe, Sten

    2013-01-01

    The computation of an optimal route for given start and destination in a static transportation network is used in many applications of private route planning. In this work we focus on route planning for emergency cars, such as for example police, fire brigade and ambulance. In case of private route planning typical quantities to be minimized are travel time or route length. However, the idea of this paper is to minimize the risk of a travel time exceeding a certain limit. This is inspired by ...

  8. MICROWAVE-ASSISTED SYNTHESIS OF NOBLE NANOSTRUCTURES

    Science.gov (United States)

    Microwave-assisted (MW) spontaneous reduction of noble metal salts, silver (Ag), gold (Au), platinum (Pt) and palladium (Pd) is reported using sugar solutions such as -D glucose, sucrose and maltose, etc. to generate nanomaterials. These MW-assisted reactions, conducted in aqueo...

  9. SCRAM: A Sharing Considered Route Assignment Mechanism for Fair Taxi Route Recommendations

    OpenAIRE

    Qian, Shiyou; Cao, Jian; Le Mouël, Frédéric; Sahel, Issam; Li, Minglu

    2015-01-01

    Recommending routes for a group of competing taxi drivers is almost untouched in most route recommender systems. For this kind of problem, recommendation fairness and driving efficiency are two fundamental aspects. In the paper, we propose SCRAM, a sharing considered route assignment mechanism for fair taxi route recommendations. SCRAM aims to provide recommendation fairness for a group of competing taxi drivers, without sacrificing driving efficiency. By designing a concise route assignment ...

  10. Dynamic information routing in complex networks

    Science.gov (United States)

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-01-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function. PMID:27067257

  11. Dynamic information routing in complex networks

    Science.gov (United States)

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-04-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function.

  12. VANET Routing Protocols: Pros and Cons

    CERN Document Server

    Paul, Bijan; Bikas, Md Abu Naser

    2012-01-01

    VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Due to rapid topology changing and frequent disconnection makes it difficult to design an efficient routing protocol for routing data among vehicles, called V2V or vehicle to vehicle communication and vehicle to road side infrastructure, called V2I. The existing routing protocols for VANET are not efficient to meet every traffic scenarios. Thus design of an efficient routing protocol has taken significant attention. So, it is very necessary to identify the pros and cons of routing protocols which can be used for further improvement or development of any new routing protocol. This paper presents the pros and cons of VANET routing protocols for inter vehicle communication.

  13. Study of barytocalcite as a conditioning matrix for carbon 14: Comparison of several synthesis routes

    Energy Technology Data Exchange (ETDEWEB)

    Massoni, Nicolas, E-mail: nicolas.massoni@cea.fr; Rosen, Jeremy; Chartier, Myriam; Cozzika, Théodore

    2013-10-15

    Carbon-14 arising from the spent nuclear fuel reprocessing can disseminate into natural cycles and then its sequestration could be advantageous. In this study, we focus on the ceramic phase barytocalcite BaCa(CO{sub 3}){sub 2} (8.08 wt.% C) obtained from different synthesis routes. We show that several elaboration routes are possible but only two emerge ensuring a high reaction yield for a fast process. The first is a room temperature aqueous precipitation with nitrated precursors and the other is a double salt high temperature reaction with carbonated starting compounds, both of these precursors being compatible with the usual carbon-14 trapping process. The sensibility to experimental conditions of reference synthesis route and the reaction mechanisms are investigated and discussed.

  14. Potential Routes for Thermochemical Biorefineries

    OpenAIRE

    García Haro, Pedro; Ollero de Castro, Pedro Antonio; Vidal-Barrero, José Fernando; Villanueva Perales, Ángel Luis

    2013-01-01

    This critical review focuses on potential routes for the multi-production of chemicals and fuels in the framework of thermochemical biorefineries. The up-to-date research and development in this field has been limited to BTL/G (biomass-to-liquids/gases) studies, where biomass-derived synthesis gas (syngas) is converted into a single product with/without the co-production of electricity and heat. Simultaneously, the interest on biorefineries is growing but mostly refers to the biochemical proc...

  15. The line planning routing game

    OpenAIRE

    Gattermann, P.; Schiewe, A.; Schmidt, M.

    2014-01-01

    In this paper, we propose a novel algorithmic approach to solve line planning problems. To this end, we model the line planning problem as a game where the passengers are players which aim at minimizing individual objective functions composed of travel time, transfer penalties, and a share of the overall cost of the solution. To find equilibria of this routing game, we use a best-response algorithm. We investigate, under which conditions on the line planning model a passenger’s best-response ...

  16. The line planning routing game

    OpenAIRE

    Gattermann, Philine; Schiewe, Alexander; Schmidt, Marie

    2014-01-01

    textabstractIn this paper, we propose a novel algorithmic approach to solve line planning problems. To this end, we model the line planning problem as a game where the passengers are players which aim at minimizing individual objective functions composed of travel time, transfer penalties, and a share of the overall cost of the solution. To find equilibria of this routing game, we use a best-response algorithm. We investigate, under which conditions on the line planning model a passenger’s be...

  17. Foreign assistance

    International Nuclear Information System (INIS)

    This paper reports that providing energy assistance to developing countries remains a relatively low priority of the Agency for International Development. AID is helping some developing countries meet their energy needs, but this assistance varies substantially because of the agency's decentralized structure. Most AID energy funding has gone to a handful of countries-primarily Egypt and Pakistan. With limited funding in most other countries, AID concentrates on providing technical expertise and promoting energy policy reforms that will encourage both energy efficiency and leverage investment by the private sector and other donors. Although a 1989 congressional directive to pursue a global warming initiative has had a marginal impact on the agency's energy programming, many AID energy programs, including those directed at energy conservation, help address global warming concerns

  18. RECONFIGURABLE PRODUCT ROUTING AND CONTROL FOR MASS CUSTOMISATION MANUFACTURING

    Directory of Open Access Journals (Sweden)

    A. J. Walker

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT:Reconfigurable control of flexible manufacturing systems can allow for the efficient and responsive production of customised product instances. This can aid in providing make-to-order business models for various small- to medium-sized enterprises in South Africa, and provide competitive advantage in a dynamic global marketplace. Reconfigurable control application requires an understanding of the modes of production variability in mass customisation manufacturing. Temporally uncorrelated workflow routings are considered as one of these production variability modes. In this light, this paper addresses the flexible material payload routing problem, and presents a mobile robot platform that has been developed to research and design reconfigurable routing systems.

    AFRIKAANSE OPSOMMING:Verstelbare beheer van aanpasbare vervaardigingstelsels kan die doeltreffende en reaktiewe produksie van doelgemaakte produkeksemplare toelaat. Hierdie beheer kan assisteer in die voorsiening van vervaardig-na-bestellingbesigheidsmodelle aan ’n aantal klein- tot medium-grootte ondernemings in Suid-Afrika, en aan hulle ’n kompeterende voorsprong bied in ’n dinamiese globale mark. Die instelling van verstelbare beheer vereis dat die modi van produkveranderlikheid in massa verbruikersaanpassingsvervaardiging verstaan word. Hierdie artikel spreek die probleem van aanpasbare roetebepaling van materiaalvragte in massa verbruikersaanpassingsvervaardiging aan. ’n Mobiele robot-platform, ontwikkel vir navorsing in verstelbare roetebepalingstelsels, word ook voorgelê.

  19. Energy Efficient Routing Protocol for MANET

    Directory of Open Access Journals (Sweden)

    S.Gopinath

    2012-03-01

    Full Text Available In recent years, many energy-efficient routing protocols have been proposed. However, very little efforts have been taken in studying the energy consumption of individual node, overhead and route maintaining issues. While not considering the design of energy efficient routing protocol, it may perform very worst than the normal routing protocol. Here, we have proposed On Demand Based Energy Efficient Routing Protocol (ODBEERP. The main aim of proposed protocol is to discover the minimum power-limitation route. The power limitation of a route is decided by the node which has the minimum energy in that route. So compared with the minimum node energy in any other route, the minimum node energy in the minimum power-limitation route has more energy. We have also proposed a more accurate analysis to track the energy consumptions due to various factors, and improve the performance during path discovery and in mobility scenarios. The proposed protocol is evaluated with object oriented discrete event simulator environment. Simulation results shows that the ODBEERP achieves good throughput, less delay, high packet delivery ratio and good energy efficiency than the existing protocol PEER.

  20. Load Balancing Routing with Bounded Stretch

    Directory of Open Access Journals (Sweden)

    Chen Siyuan

    2010-01-01

    Full Text Available Routing in wireless networks has been heavily studied in the last decade. Many routing protocols are based on classic shortest path algorithms. However, shortest path-based routing protocols suffer from uneven load distribution in the network, such as crowed center effect where the center nodes have more load than the nodes in the periphery. Aiming to balance the load, we propose a novel routing method, called Circular Sailing Routing (CSR, which can distribute the traffic more evenly in the network. The proposed method first maps the network onto a sphere via a simple stereographic projection, and then the route decision is made by a newly defined "circular distance" on the sphere instead of the Euclidean distance in the plane. We theoretically prove that for a network, the distance traveled by the packets using CSR is no more than a small constant factor of the minimum (the distance of the shortest path. We also extend CSR to a localized version, Localized CSR, by modifying greedy routing without any additional communication overhead. In addition, we investigate how to design CSR routing for 3D networks. For all proposed methods, we conduct extensive simulations to study their performances and compare them with global shortest path routing or greedy routing in 2D and 3D wireless networks.

  1. Bicretieria Optimization in Routing Games

    CERN Document Server

    Busch, Costas

    2008-01-01

    Two important metrics for measuring the quality of routing paths are the maximum edge congestion $C$ and maximum path length $D$. Here, we study bicriteria in routing games where each player $i$ selfishly selects a path that simultaneously minimizes its maximum edge congestion $C_i$ and path length $D_i$. We study the stability and price of anarchy of two bicriteria games: - {\\em Max games}, where the social cost is $\\max(C,D)$ and the player cost is $\\max(C_i, D_i)$. We prove that max games are stable and convergent under best-response dynamics, and that the price of anarchy is bounded above by the maximum path length in the players' strategy sets. We also show that this bound is tight in worst-case scenarios. - {\\em Sum games}, where the social cost is $C+D$ and the player cost is $C_i+D_i$. For sum games, we first show the negative result that there are game instances that have no Nash-equilibria. Therefore, we examine an approximate game called the {\\em sum-bucket game} that is always convergent (and ther...

  2. An Improved Multi-Objective Programming with Augmented ε-Constraint Method for Hazardous Waste Location-Routing Problems

    OpenAIRE

    Hao Yu; Wei Deng Solvang

    2016-01-01

    Hazardous waste location-routing problems are of importance due to the potential risk for nearby residents and the environment. In this paper, an improved mathematical formulation is developed based upon a multi-objective mixed integer programming approach. The model aims at assisting decision makers in selecting locations for different facilities including treatment plants, recycling plants and disposal sites, providing appropriate technologies for hazardous waste treatment, and routing tran...

  3. Vehicle routing problem in investment fund allocation

    Science.gov (United States)

    Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Mohd, Ismail

    2013-04-01

    Since its introduction by Dantzig and Ramser in 1959, vehicle routing problem keeps evolving in theories, applications and variability. The evolution in computing and technology are also important contributors to research in solving vehicle routing problem. The main sectors of interests among researchers and practitioners for vehicle routing problem are transportation, distribution and logistics. However, literature found that concept and benefits of vehicle routing problem are not taken advantages of by researchers in the field of investment. Other methods found used in investment include multi-objective programming, linear programming, goal programming and integer programming. Yet the application of vehicle routing problem is not fully explored. A proposal on a framework of the fund allocation optimization using vehicle routing problem is presented here. Preliminary results using FTSE Bursa Malaysia data testing the framework are also given.

  4. Dynamic information routing in complex networks

    CERN Document Server

    Kirst, Christoph; Battaglia, Demian

    2015-01-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this generic mechanism specifically for oscillatory dynamics and analyze how individual unit properties, the network topology and external inputs coact to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine non-local network-wide communication. These results help...

  5. Zone routing in a torus network

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip; Kumar, Sameer

    2013-01-29

    A system for routing data in a network comprising a network logic device at a sending node for determining a path between the sending node and a receiving node, wherein the network logic device sets one or more selection bits and one or more hint bits within the data packet, a control register for storing one or more masks, wherein the network logic device uses the one or more selection bits to select a mask from the control register and the network logic device applies the selected mask to the hint bits to restrict routing of the data packet to one or more routing directions for the data packet within the network and selects one of the restricted routing directions from the one or more routing directions and sends the data packet along a link in the selected routing direction toward the receiving node.

  6. Predicting transportation routes for radioactive wastes

    International Nuclear Information System (INIS)

    Oak Ridge National Laboratory (ORNL) has been involved in transportation logistics of radioactive wastes as part of the overall waste transportation program. A Spent Fuel Logistics Model (SFLM), was developed to predict overall material balances representing the flow of spent fuel assemblies from reactors to away-from-reactor storage facilities and/or to federal repositories. The transportation requirements to make these shipments are also itemized. The next logical step in the overall transportation project was the development of a set of computer codes which would predict likely transportation routes for waste shipments. Two separate routing models are now operational at ORNL. Routes for truck transport can be estimated with the HIGHWAY program, and rail and barge routes can be predicted with the INTERLINE model. This paper discusses examples of the route estimates and applications of the routing models

  7. Modified Rumor Routing for Wireless Sensor Networks

    OpenAIRE

    Chiranjib Patra; Parama Bhaumik; Debina Chakroborty

    2010-01-01

    Due to the limited processing power, and finite power available to each sensor node, regular ad-hoc routing techniques cannot be directly applied to sensor networks domain. Thus, energy-efficient routing algorithms suitable to the inherent characteristics of these types of networks are needed. However highly efficient data centric model of routing will improve the longevity of the network. This paper describes a mechanism of improvisation through simulation of existing feature of Rumor routin...

  8. Routing in Wireless Networks with Position Trees

    OpenAIRE

    Chavez, Edgar; Mitton, Nathalie; Tejeda, Hector

    2007-01-01

    Sensor networks are wireless adhoc networks where all the nodes cooperate for routing messages in the absence of a fixed infrastructure. Non-flooding, guaranteed delivery routing protocols are preferred because sensor networks have limited battery life. Location aware routing protocols are good candidates for sensor network applications, nevertheless they need either an external location service like GPS or Galileo (which are bulky, energy consuming devices) or internal location services prov...

  9. Learning multiple routes in homing pigeons

    OpenAIRE

    Flack, Andrea; Guilford, Tim; Biro, Dora

    2014-01-01

    The aerial lifestyle of central-place foraging birds allows wide-ranging movements, raising fundamental questions about their remarkable navigation and memory systems. For example, we know that pigeons (Columba livia), long-standing models for avian navigation, rely on individually distinct routes when homing from familiar sites. But it remains unknown how they cope with the task of learning several routes in parallel. Here, we examined how learning multiple routes influences homing in pigeon...

  10. Towards Building an Intelligent Call Routing System

    OpenAIRE

    Thien Khai Tran; Dung Minh Pham; Binh Van Huynh

    2016-01-01

    This paper presents EduICR - an Intelligent Call Routing system. This system can route calls to the most appropriate agent using routing rules built by the text classifier. EduICR includes the following main components: telephone communication network; Vietnamese speech recognition; Text classifier/ Natural language processor and Vietnamese speech synthesis. To our best knowledge, this is one of the first systems in Vietnam to implement the integration mechanism of text processing and speech ...

  11. Martel's routes in Mammoth cave, Kentucky, 1912.

    OpenAIRE

    Shaw Trevor R.

    2003-01-01

    Martel’s own copy of the Hovey 1912 guidebook to Mammoth Cave has his routes marked faintly in pencil on the printed cave plans. These plans are reproduced here, with his routes indicated on them. He generally followed the four standard tourist routes which now included Kaemper’s 1908 discoveries to Violet City, but instead of visiting the Maelstrom he went to Hovey’s Cathedral and Gerta’s Grotto.

  12. Routing Protocols in MANET: Comparative Study

    OpenAIRE

    Jayanti; Vikram Nandal

    2014-01-01

    A Mobile Ad Hoc Network (MANET) is composed of mobile nodes without any infrastructure like wireless access points or base stations. MANET describes wireless, mobile and multi-hop networks that operate without the benefit of any existing infrastructure except for the nodes themselves. The main goal of an ad hoc network routing protocol is to establish correct and efficient route between a pair of mobile nodes so that messages delivered within the active route timeout interval. Several protoco...

  13. An Anonymous Secure Routing Using OLSR Protocol

    OpenAIRE

    Osiers Gyamfuah Grace; Dr. John Rajan

    2013-01-01

    Security and privacy concerns are major issues to be considered in Mobile Ad hoc Networking (MANET). Several routing protocols have been proposed to achieve both routing and data packets security. In order to achieve privacy, the anonymous routing concept has been introduced and few protocols have been proposed for use in this area. In this paper, global position system (GPS) device is used to obtain the current location of nodes and with the help of a cryptographic algorithm incorporated int...

  14. Gender differences in virtual route learning

    OpenAIRE

    Larios, Hector

    2011-01-01

    Past studies have found evidence of gender differences in route-learning strategies, indicating that men rely on configurational strategies (e.g., cardinal directions) and women rely on topographic strategies (e.g., landmarks). Whether and how these gender differences in route-learning strategies extend to virtual environments is not fully known. In this dissertation, I investigated gender differences in learning virtual routes from two frames of reference- egocentric and allocentric. One hun...

  15. Advances in optimal routing through computer networks

    Science.gov (United States)

    Paz, I. M.

    1977-01-01

    The optimal routing problem is defined. Progress in solving the problem during the previous decade is reviewed, with special emphasis on technical developments made during the last few years. The relationships between the routing, the throughput, and the switching technology used are discussed and their future trends are reviewed. Economic aspects are also briefly considered. Modern technical approaches for handling the routing problems and, more generally, the flow control problems are reviewed.

  16. Investigation on the shape evolution of 1D mesoporous hematite nanoparticles prepared via anion-assisted hydrothermal approach

    Energy Technology Data Exchange (ETDEWEB)

    Jayashainy, J.; Sagayaraj, P., E-mail: psagayaraj@hotmail.com

    2015-03-25

    Graphical abstract: Hematite nanotires are formed by an anion assisted hydrothermal process at a temperature of 220 °C with a reaction time of 48 h. However, when the synthesis was carried out by including sulfate ion along with phosphate ion without altering the reaction temperature and time, it led to the formation of hematite NTs. - Highlights: • 1D mesoporous hematite nanostructures are synthesized via anion assisted process. • The structural evolution is investigated by considering the experimental conditions. • Weak ferromagnetic behavior and high coercivity was observed in the samples. - Abstract: The fabrication of one-dimensional (1D) porous hematite (α-Fe{sub 2}O{sub 3}) nanorods, nanotires and nanotubes employing an anion-assisted hydrothermal route is reported. The shape evolution of the resulting nanostructures is investigated taking into account the role of the phosphate and sulfate anions along with other experimental conditions. Field Emission Scanning Electron Microscope (FESEM) and High Resolution Transmission Electron microscope (HRTEM) images confirm the 1D morphology and porous nature of the prepared samples. Fourier Transform Infrared (FT-IR) and FT-Raman spectral analysis are carried out. Brunauer–Emmett–Teller (BET) measurements show the surface area and distribution of porosity in the as-prepared nanoparticles. The thermal stability of the samples is analyzed by employing Thermogravimetric (TG) and Differential Thermal Analysis (DTA). The effect of anisotropic shape over the magnetic property of the samples prepared under different synthetic conditions is studied using Vibrating Sample Magnetometer (VSM)

  17. Flood Routing Technique for Data Networks

    OpenAIRE

    Cho, Jaihyung; Breen, James

    1998-01-01

    In this paper, a new routing algorithm based on a flooding method is introduced. Flooding techniques have been used previously, e.g. for broadcasting the routing table in the ARPAnet [1] and other special purpose networks [3][4][5]. However, sending data using flooding can often saturate the network [2] and it is usually regarded as an inefficient broadcast mechanism. Our approach is to flood a very short packet to explore an optimal route without relying on a pre-established routing table, a...

  18. Security Attacks On MANET Routing Protocols

    Directory of Open Access Journals (Sweden)

    Chiragkumar V. Patel

    2013-10-01

    Full Text Available The paper gives idea about various routing protocols for Mobile Ad-Hoc Network against security issues. MANET is vulnerable to various security attacks due to its dynamically changing topology, self configurable nature and lack of centralized control. Malicious node can significantly degrade the performance and reliability of Ad-hoc Network routing protocols. From the survey it has been made quite clear that basic MANET protocols are vulnerable to various routing attacks. While Secure AODV (SAODV routing protocol performs quite well to improve performance in presence of security attack in MANET.

  19. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  20. A Green Approach to the Synthesis of Biologically Important Indeno[2,1-e]pyrazolo[5,4-b]pyridines via Microwave-assisted Multi-component Reactions in Water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A green approach to the synthesis of biologically important indeno[2,1-e]pyrazolo[5,4-b]pyridines was suc-cessfully realized via multi-component reactions of aldehyde, 3-methyl-l-phenyl-1H-pyrazol-5-amine and 1,3-indanedione in water under microwave irradiation without catalyst. This protocol has the prominent advantages of environmental-friendliness, short reaction time, excellent yields, low cost, easy operation as well as broad scope of applicability.

  1. A study of thermal properties of sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Highlights: • The microwave-assisted hydrothermal route was used for titanate nanotubes synthesis. • Conversion to single-phase nanotube morphology completes after 8 h reaction time. • The nanotube morphology is stable up to 600 °C, as determined by in-situ XRD and SEM. • Sodium ions migrate to the surface due to thermal motion and structure condensation. - Abstract: Sodium titanate nanotubes (NaTiNTs) were synthesized by microwave-assisted hydrothermal treatment of commercial TiO2, at constant temperature (135 °C) and different irradiation times (15 min, 1, 4, 8 and 16 h). The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry and specific surface area measurements. The irradiation time turned out to be the key parameter for morphological control of the material. Nanotubes were observed already after 15 min of microwave irradiation. The analyses of the products irradiated for 8 and 16 h confirm the complete transformation of the starting TiO2 powder to NaTiNTs. The nanotubes are open ended with multi-wall structures, with the average outer diameter of 8 nm and specific surface area up to 210 m2/g. The morphology, surface area and crystal structure of the sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method were similar to those obtained by conventional hydrothermal method

  2. A study of thermal properties of sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Preda, Silviu, E-mail: predas01@yahoo.co.uk [Institute of Physical Chemistry “Ilie Murgulescu”, 202 Splaiul Independentei, 060021 Bucharest (Romania); Rutar, Melita [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Jožef Stefan International Postgraduate School, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Umek, Polona [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Zaharescu, Maria [Institute of Physical Chemistry “Ilie Murgulescu”, 202 Splaiul Independentei, 060021 Bucharest (Romania)

    2015-11-15

    Highlights: • The microwave-assisted hydrothermal route was used for titanate nanotubes synthesis. • Conversion to single-phase nanotube morphology completes after 8 h reaction time. • The nanotube morphology is stable up to 600 °C, as determined by in-situ XRD and SEM. • Sodium ions migrate to the surface due to thermal motion and structure condensation. - Abstract: Sodium titanate nanotubes (NaTiNTs) were synthesized by microwave-assisted hydrothermal treatment of commercial TiO{sub 2}, at constant temperature (135 °C) and different irradiation times (15 min, 1, 4, 8 and 16 h). The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry and specific surface area measurements. The irradiation time turned out to be the key parameter for morphological control of the material. Nanotubes were observed already after 15 min of microwave irradiation. The analyses of the products irradiated for 8 and 16 h confirm the complete transformation of the starting TiO{sub 2} powder to NaTiNTs. The nanotubes are open ended with multi-wall structures, with the average outer diameter of 8 nm and specific surface area up to 210 m{sup 2}/g. The morphology, surface area and crystal structure of the sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method were similar to those obtained by conventional hydrothermal method.

  3. Bus Routes, Marta Bus Routes located in Transportation database, Published in unknown, City of Roswell, GA.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Bus Routes dataset as of unknown. It is described as 'Marta Bus Routes located in Transportation database'. Data by this publisher are often provided in State...

  4. Transportation routing analysis geographic information system - tragis, progress on improving a routing tool

    International Nuclear Information System (INIS)

    The Transportation Routing Analysis Geographic Information System (TRAGIS) model provides a useful tool to calculate and analyze transportation routes for radioactive materials within the continental United States. This paper outlines some of the features available in this model. (authors)

  5. Transportation Routing Analysis Geographic Information System -- TRAGIS, progress on improving a routing tool

    International Nuclear Information System (INIS)

    The Transportation Routing Analysis Geographic Information System (TRAGIS) model provides a useful tool to calculate and analyze transportation routes for radioactive materials within the continental US. This paper outlines some of the features available in this model

  6. US Hazardous Materials Routes, Geographic WGS84, BTS (2006) [hazardous_material_routes_BTS_2006

    Data.gov (United States)

    Louisiana Geographic Information Center — The Federal Motor Carrier Safety Administration (FMCSA) Hazardous Material Routes were developed using the 2004 First Edition TIGER/Line files. The routes are...

  7. A Privacy-Preserving Prediction Method for Human Travel Routes

    Directory of Open Access Journals (Sweden)

    Wen-Chen Hu

    2014-12-01

    Full Text Available This paper proposes a kind of location-based research, human travel route prediction, which is to predict the track of a subject's future movements. The proposed method works as follows. The mobile user sends his/her current route along with several dummy routes to the server by using a 3D route matrix, which encodes a set of routes. The server restores the routes from the 3D matrix and matches the restored routes to the saved routes. The predicted route is found as the trunk of the tree, which is built by superimposing the matching results. The server then sends the predicted routes back to the user, who will apply the predicted route to a real-world problem such as traffic control and planning. Preliminary experimental results show the proposed method successfully predicts human travel routes based on current and previous routes. User privacy is also rigorously protected by using a simple method of dummy routes.

  8. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  9. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  10. Network Resilience through Multiple Routing Configurations

    Directory of Open Access Journals (Sweden)

    Naga Raju Pamidi

    2011-11-01

    Full Text Available We propose the use of multi-topology (MT routing for network resilience against link and node failures. We describe the multi-topologies by an n-dimensional vector of different link costs for all links in the network. It is the base for the calculation of n shortest path trees from any node to all other destinations, i.e. for n virtual routing topologies. We define the link costs in such a way that the routing topologies complement each other in the sense that at least one valid route remains in a single link or node failure scenario for each pair of nodes in at least one routing topology. In such a failure case, packets are rather deviated over the intact routing topology than discarded. The recovery speed of the presented mechanism is very fast and can be compared to fast rerouting mechanisms in MPLS, which reduce packet, drops to a minimum. In contrast to MPLS, MT routing is still a pure IP-based solution that retains the scalability and the robustness of IP routing. As the Internet takes an increasingly central role in our communications infrastructure, the slow convergence of routing protocols after a network failure becomes a growing problem. To assure fast recovery from link and node failures in IP networks, we present a new recovery scheme called Multiple Routing Configurations (MRC. Our proposed scheme guarantees recovery in all single failure scenarios, using a single mechanism to handle both link and node failures, and without knowing the root cause of the failure. MRC is strictly connectionless, and assumes only destination based hop-by-hop forwarding. MRC is based on keeping additional routing information in the routers, and allows packet forwarding to continue on an alternative output link immediately after the detection of a failure. It can be implemented with only minor changes to existing solutions.

  11. Routes visualization: Automated placement of multiple route symbols along a physical network infrastructure

    OpenAIRE

    Jules Teulade-Denantes; Adrien Maudet; Cécile Duchêne

    2015-01-01

    This paper tackles the representation of routes carried by a physical network infrastructure on a map. In particular, the paper examines the case where each route is represented by a separate colored linear symbol offset from the physical network segments and from other routes—as on public transit maps with bus routes offset from roads. In this study, the objective is to automate the placement of such route symbols while maximizing their legibility, especially at junctions. The problem is mod...

  12. Metal triflate-mediated coupling of allylgermanes with thiols: a facile route to thiogermanes.

    Science.gov (United States)

    Kuciński, K; Pawluć, P; Hreczycho, G

    2015-06-28

    A novel coupling reaction of thiols with (2-methylallyl)germanes catalyzed by metal triflates has been developed. This reaction provides a direct and efficient method to afford thiogermanes and opens a valuable and general synthetic route for the Ge-S cross-coupling with the elimination of isobutylene as a single by-product. Scandium(iii) triflate demonstrates the highest catalytic activity among the tested triflates. All reactions were carried out under extremely mild conditions to give thiogermanes in excellent yields. This Ge-S coupling reaction shows high generality for the variety of thiols. PMID:26006777

  13. Nuclear Reactions

    OpenAIRE

    Bertulani, C. A.

    2009-01-01

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay of compound nuclei;...

  14. New cross section data and review of production routes of medically used $^{110m}$In

    CERN Document Server

    Tárkányi, F; Ditrói, F; Hermanne, A; Baba, M; Mohsena, B M A; Ignatyuk, A V

    2016-01-01

    Evaluation of nuclear data for production routes of $^{110m}$In is in progress in the frame of an IAEA Coordinated Research Project (CRP). New experimental cross section data for the indirect $^{nat}$In(p,x)$^{110}$Sn $\\longrightarrow$ $^{110m}$In and for the direct $^{107}$Ag($\\alpha$,n)$^{110m}$In and $^{109}$Ag($^{3}$He,2n)$^{110m}$In production routes and for the satellite impurity reactions $^{107}$Ag($\\alpha$,xn)$^{110g,109}$In and $^{109}$Ag($^{3}$He,xn)$^{110g,111,109}$In have been measured by using the activation method, stacked foil irradiation technique and gamma-ray spectrometry. Additional data are reported for production of the $^{111}$In diagnostic gamma-emitter via the $^{109}$Ag($\\alpha$,2n)$^{111}$In reaction. The earlier experimental data were critically reviewed in order to prepare recommended data and optimal production parameters for the different routes.

  15. Optimizing departure times in vehicle routes

    NARCIS (Netherlands)

    Kok, A.L.; Hans, E.W.; Schutten, J.M.J.

    2008-01-01

    Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. However, in practice, temporal traffic congestions make that such solutions are not optimal with respect to minimizing the total duty time. Furthermore, VRPTW sol

  16. Environmental factors along the Northern Sea Route

    International Nuclear Information System (INIS)

    The Northern Sea Route runs ca 5,600 nautical miles across the top of Russia from Murmansk to Vladivostok, and includes half of the Arctic basin. An environmental impact assessment is needed for this route because of the potential for commercial shipping to disturb the vulnerable Arctic environment along the route. For example, Russian development of oil and gas resources in the area served by the route is expected to rise dramatically in the near future. Drilling in the route area offshore has already begun, and potential blowouts or tanker spills are of concern. A pilot study on the environment along this route was conducted in 1990/91, focusing on a study of the literature and communications with Russian scientists working on Arctic ecology. Existing data seem to be insufficient and generally only cover the westernmost and easternmost parts of the route. A five-year research plan is proposed to provide an inventory of Arctic species in the route area and levels of contaminants present, to assess the environmental sensitivity of the area, and analyze impacts that increased shipping might have on the environment. Protection measures will also be suggested. 1 fig

  17. Energy Efficient Routing in Nomadic Networks

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Bouvin, Niels Olof

    2007-01-01

    We present an evaluation of a novel energy-efficient routing protocol for mobile ad-hoc networks. We combine two techniques for optimizing energy levels with a well-known routing protocol. We examine the behavior of this combination in a nomadic network setting, where some nodes are stationary and...

  18. Secure Geographic Routing Protocols: Issues and Approaches

    OpenAIRE

    Mehdi sookhak; Ramin Karimi; NorafidaIthnin; Mahboobeh Haghparast; Ismail FauziISnin

    2011-01-01

    In the years, routing protocols in wireless sensor networks (WSN) have been substantially investigated by researches Most state-of-the-art surveys have focused on reviewing of wireless sensor network .In this paper we review the existing secure geographic routing protocols for wireless sensor network (WSN) and also provide a qualitative comparison of them.

  19. TBRF: Trust Based Routing Framework for WSNs

    Directory of Open Access Journals (Sweden)

    Kushal Gulaskar

    2014-03-01

    Full Text Available The multi-hop routing in wireless sensor networks (WSNs offers little protection against identity deception through replaying routing information. An adversary can exploit this defect to launch various harmful or even devastating attacks against the routing protocols, including sinkhole attacks, wormhole attacks and Sybil attacks. The situation is further aggravated by mobile and harsh network conditions. Traditional cryptographic techniques or efforts at developing trust-aware routing protocols do not effectively address this severe problem. To secure the WSNs against adversaries misdirecting the multi-hop routing, we have designed and implemented TBRF, a robust trust-aware routing framework for dynamic WSNs. Without tight time synchronization or known geographic information, TBRF provides trustworthy and energy-efficient route. Most importantly, TBRF proves effective against those harmful attacks developed out of identity deception; the resilience of TBRF is verified through extensive evaluation with both simulation and empirical experiments on large-scale WSNs under various scenarios including mobile and RF-shielding network conditions. Further, we have implemented a low-overhead TBRF module in TinyOS; as demonstrated, this implementation can be incorporated into existing routing protocols with the least effort. Based on TBRF, we also demonstrated a proof-of-concept mobile target detection application that functions well against an anti-detection mechanism

  20. Secure Geographic Routing Protocols: Issues and Approaches

    CERN Document Server

    sookhak, Mehdi; Haghparast, Mahboobeh; ISnin, Ismail Fauzi

    2011-01-01

    In the years, routing protocols in wireless sensor networks (WSN) have been substantially investigated by researches. Most state-of-the-art surveys have focused on reviewing of wireless sensor network .In this paper we review the existing secure geographic routing protocols for wireless sensor network (WSN) and also provide a qualitative comparison of them.

  1. Parallel Genetic Algorithm for Channel Routing

    OpenAIRE

    Rao, Prahlada BB; Patnaik, LM; Hansdah, RC

    1993-01-01

    In this paper, we propose a new channel routing algorithm based on genetic approach. This involves designing a new encoding scheme and an evaluation function used by the genetic algorithm (GA) for channel routing problem. The algorithm has been implemented as both sequential and distributed CA. The speedup achieved is positive and encouraging.

  2. ROUTE CHOICE MODELLING FOR BICYCLE TRIPS

    Directory of Open Access Journals (Sweden)

    Ehsan Beheshtitabar

    2014-06-01

    Full Text Available This paper intends to find out which parameters have the highest influence on bicyclists’ route-choice-behaviour and how they contribute. There are many attributes considered throughout different studies that are favoured by cyclists. The attributes are the basis for generating a function which predicts the route choice of cyclists. The paper aims at making a comparison between distance-based routes and attribute-based routes. The model for creating the bicycle route choice program is based on the network model of Norrköping, Sweden. The preferred attributes of the model each assign a weight in the cost function of the model for each link of the urban network. The algorithm of the lowest cost function route searches the shortest path in terms of assigned link costs over the whole network. For comparing the results of the cost function and the shortest route (between an origin-destination, the model has a shortest path finding algorithm between different Origin and Destination pairs implemented. It has been viewed that around 25% of all cumulative routes do not show any distance differences between the shortest path distance and attributes based solution. With the used weights of the Standard scenario, it can be seen that the trade-off between shortest distance and safety respectively comfort can be optimized, fulfilling both criteria (distance and safety/comfort.

  3. Using Collective Intelligence to Route Internet Traffic

    OpenAIRE

    David H. Wolpert; Tumer, Kagan; Frank, Jeremy

    1999-01-01

    A COllective INtelligence (COIN) is a set of interacting reinforcement learning (RL) algorithms designed in an automated fashion so that their collective behavior optimizes a global utility function. We summarize the theory of COINs, then present experiments using that theory to design COINs to control internet traffic routing. These experiments indicate that COINs outperform all previously investigated RL-based, shortest path routing algorithms.

  4. Secure Geographic Routing Protocols: Issues and Approaches

    Directory of Open Access Journals (Sweden)

    Mehdi sookhak

    2011-09-01

    Full Text Available In the years, routing protocols in wireless sensor networks (WSN have been substantially investigated by researches Most state-of-the-art surveys have focused on reviewing of wireless sensor network .In this paper we review the existing secure geographic routing protocols for wireless sensor network (WSN and also provide a qualitative comparison of them.

  5. Caspian producers contemplate excess of export routes

    International Nuclear Information System (INIS)

    The fourth quarter of 2005 sees the commissioning of the latest oil export route from the Caspian: the Baku-Tbilisi-Ceyhan (BTC) pipeline from Azerbaijan to Turkey. BTC is one of a series of potential export routes from Central Asia and the Trans-Caucasus. The proposed capacity of all these routes, however, far exceeds the volume of oil likely to be available to fill it at any time in the foreseeable future. Turkey nevertheless continues to press for more export capacity in an attempt to reduce the number of tankers passing through the narrow waterways that connect the Black Sea with the Mediterranean. For their part, Caspian oil producers want their oil to be transported by the cheapest and most direct route, which appears to rule out pipelines designed to divert their exports away from the Black Sea-Mediterranean sea-route. (author)

  6. Highway and interline transportation routing models

    International Nuclear Information System (INIS)

    The potential impacts associated with the transportation of hazardous materials are important issues to shippers, carriers, and the general public. Since transportation routes are a central characteristic in most of these issues, the prediction of likely routes is the first step toward the resolution of these issues. In addition, US Department of Transportation requirements (HM-164) mandate specific routes for shipments of highway controlled quantities of radioactive materials. In response to these needs, two routing models have been developed at Oak Ridge National Laboratory under the sponsorship of the U.S. Department of Energy (DOE). These models have been designated by DOE's Office of Environmental Restoration and Waste Management, Transportation Management Division (DOE/EM) as the official DOE routing models. Both models, HIGHWAY and INTERLINE, are described

  7. Individuality in bird migration: routes and timing.

    Science.gov (United States)

    Vardanis, Yannis; Klaassen, Raymond H G; Strandberg, Roine; Alerstam, Thomas

    2011-08-23

    The exploration of animal migration has entered a new era with individual-based tracking during multiple years. Here, we investigated repeated migratory journeys of a long-distance migrating bird, the marsh harrier Circus aeruginosus, in order to analyse the variation within and between individuals with respect to routes and timing. We found that there was a stronger individual repeatability in time than in space. Thus, the annual timing of migration varied much less between repeated journeys of the same individual than between different individuals, while there was considerable variation in the routes of the same individual on repeated journeys. The overall contrast in repeatability between time and space was unexpected and may be owing to strong endogenous control of timing, while short-term variation in environmental conditions (weather and habitat) might promote route flexibility. The individual variation in migration routes indicates that the birds navigate mainly by other means than detailed route recapitulation based on landmark recognition. PMID:21307045

  8. Latent variables and route choice behavior

    DEFF Research Database (Denmark)

    Prato, Carlo Giacomo; Bekhor, Shlomo; Pronello, Cristina

    2012-01-01

    In the last decade, a broad array of disciplines has shown a general interest in enhancing discrete choice models by considering the incorporation of psychological factors affecting decision making. This paper provides insight into the comprehension of the determinants of route choice behavior by...... proposing and estimating a hybrid model that integrates latent variable and route choice models. Data contain information about latent variable indicators and chosen routes of travelers driving regularly from home to work in an urban network. Choice sets include alternative routes generated with a branch....... Estimation results illustrate that considering latent variables (i.e., memory, habit, familiarity, spatial ability, time saving skills) alongside traditional variables (e.g., travel time, distance, congestion level) enriches the comprehension of route choice behavior....

  9. New routes for allergen immunotherapy.

    Science.gov (United States)

    Johansen, Pål; von Moos, Seraina; Mohanan, Deepa; Kündig, Thomas M; Senti, Gabriela

    2012-10-01

    IgE-mediated allergy is a highly prevalent disease in the industrialized world. Allergen-specific immunotherapy (SIT) should be the preferred treatment, as it has long lasting protective effects and can stop the progression of the disease. However, few allergic patients choose to undergo SIT, due to the long treatment time and potential allergic adverse events. Since the beneficial effects of SIT are mediated by antigen presenting cells inducing Th1, Treg and antibody responses, whereas the adverse events are caused by mast cells and basophils, the therapeutic window of SIT may be widened by targeting tissues rich in antigen presenting cells. Lymph nodes and the epidermis contain high density of dendritic cells and low numbers of mast cells and basophils. The epidermis has the added benefit of not being vascularised thereby reducing the chances of anaphylactic shock due to leakage of allergen. Hence, both these tissues represent highly promising routes for SIT and are the focus of discussion in this review. PMID:23095873

  10. Drug targeting through pilosebaceous route.

    Science.gov (United States)

    Chourasia, Rashmi; Jain, Sanjay K

    2009-10-01

    Local skin targeting is of interest for the pharmaceutical and the cosmetic industry. A topically applied substance has basically three possibilities to penetrate into the skin: transcellular, intercellular, and follicular. The transfollicular path has been largely ignored because hair follicles constitute only 0.1% of the total skin. The hair follicle is a skin appendage with a complex structure containing many cell types that produce highly specialised proteins. The hair follicle is in a continuous cycle: anagen is the hair growth phase, catagen the involution phase and telogen is the resting phase. Nonetheless, the hair follicle has great potential for skin treatment, owing to its deep extension into the dermis and thus provides much deeper penetration and absorption of compounds beneath the skin than seen with the transdermal route. In the case of skin diseases and of cosmetic products, delivery to sweat glands or to the pilosebaceous unit is essential for the effectiveness of the drug. Increased accumulation in the pilosebaceous unit could treat alopecia, acne and skin cancer more efficiently and improve the effect of cosmetic substances and nutrients. Therefore, we review herein various drug delivery systems, including liposomes, niosomes, microspheres, nanoparticles, nanoemulsions, lipid nanocarriers, gene therapy and discuss the results of recent researches. We also review the drugs which have been investigated for pilosebaceous delivery. PMID:19663765

  11. Applying green chemistry to the photochemical route to artemisinin

    Science.gov (United States)

    Amara, Zacharias; Bellamy, Jessica F. B.; Horvath, Raphael; Miller, Samuel J.; Beeby, Andrew; Burgard, Andreas; Rossen, Kai; Poliakoff, Martyn; George, Michael W.

    2015-06-01

    Artemisinin is an important antimalarial drug, but, at present, the environmental and economic costs of its semi-synthetic production are relatively high. Most of these costs lie in the final chemical steps, which follow a complex acid- and photo-catalysed route with oxygenation by both singlet and triplet oxygen. We demonstrate that applying the principles of green chemistry can lead to innovative strategies that avoid many of the problems in current photochemical processes. The first strategy combines the use of liquid CO2 as solvent and a dual-function solid acid/photocatalyst. The second strategy is an ambient-temperature reaction in aqueous mixtures of organic solvents, where the only inputs are dihydroartemisinic acid, O2 and light, and the output is pure, crystalline artemisinin. Everything else—solvents, photocatalyst and aqueous acid—can be recycled. Some aspects developed here through green chemistry are likely to have wider application in photochemistry and other reactions.

  12. Physician-assisted death.

    OpenAIRE

    Senn, John S.

    1995-01-01

    Physician-assisted death includes both euthanasia and assistance in suicide. The CMA urges its members to adhere to the principles of palliative care. It does not support euthanasia and assisted suicide. The following policy summary includes definitions of euthanasia and assisted suicide, background information, basic ethical principles and physician concerns about legalization of physician-assisted death.

  13. Hartlepool/Heysham 1 fuel route consolidation and development

    International Nuclear Information System (INIS)

    The fuel routes at each advanced gas-cooled reactor power station are required to operate safely and reliably to keep the reactors operational. On average, about one-sixth of the total fuel inventory must be renewed each year. A variety of refuelling modes are employed at particular stations arising from detailed design, historical and safety case considerations. At Hartlepool and Heysham 1, which are of the same design, routine refuelling is done in batches with the reactors off-load and depressurized (although pressurized off-load refuelling is also permitted). The batches are as large as practicable in order to minimize output losses due to refuelling. The batch process involves both (a) the exchange of spent fuel assemblies for new ones (b) the transfer of part-burnt fuel assemblies to new positions in the core to improve fuel utilization-known as 'radial shuffling'. Once the batch is complete, a programme of irradiated fuel disposals (separating the fuel assemblies into individual fuel elements and culminating in the dispatch of fuel elements off site in flasks) and new fuel assembly builds is begun. These operations involve the use of several fuel route plant facilities including cooling ponds. The refuelling process from the build of new fuel to the final handling of complete irradiated fuel assemblies is covered by a refuelling safety case. Further safety cases exist for the handling of individual irradiated elements both on and off site. All these cases are updated as necessary via a formal plant modifications procedure and they have recently been subject to a ten-yearly periodic safety review (PSR). Arising from the PSR, work to consolidate the cases is in progress including studies in the seismic and human factors areas. Development work to improve the efficiency of the fuel route is also under way. This involves process improvements to assist operators engineered improvements to improve speed and reliability fuel utilization improvements by increases in

  14. Production of bismuth germanate ceramic scintillators by combustion synthesis route

    International Nuclear Information System (INIS)

    The present work presents the results from production of ceramic scintillator Bi4Ge3O12 (bismuth germanate – BGO), which is very sensitive to beta, gamma and X-rays. The production route adopted was combustion synthesis. In this route, the precursors germanium oxide and bismuth nitrate were mixed to urea, used as fuel, and heated up to the ignition temperature, 500 °C. The ignition starts an exothermic reaction that promotes the formation of the desired crystalline phase. It was observed a dependency of the agglomeration of the synthesized powders upon the pH of the initial mixture. The pH was controlled through the addition of ammonium dioxide, and was varied from zero up to 9. Intermediate crystalline phases were observed by DRX measurements of the product of the combustion reaction. After calcination at 600 °C/24 h, the Bi12GeO20 content was enhanced. The optimum conditions of synthesis and sintering of the samples were determined through auxiliary techniques such as DTA and SEM. The synthesized powders presented particle size near 10 nm, whereas the sintered grains reached near 2 μm. The relative density of sintered ceramics, obtained from Archimedes’ method, was 96%. (author)

  15. Proximity Aware Routing in Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Valerie Alandzi

    2007-01-01

    Full Text Available Most of the existing routing protocols for ad hoc networks are designed to scale in networks of a few hundred nodes. They rely on state concerning all links of the network or links on the route between a source and a destination. This may result in poor scaling properties in larger mobile networks or when node mobility is high. Using location information to guide the routing process is one of the most often proposed means to achieve scalability in large mobile networks. However, location-based routing is difficult when there are holes in the network topology. We propose a novel position-based routing protocol called Proximity Aware Routing for Ad-hoc networks (PARA to address these issues. PARA selects the next hop of a packet based on 2-hops neighborhood information. We introduce the concept of “proximity discovery”. The knowledge of a node’s 2-hops neighborhood enables the protocol to anticipate concave nodes and helps reduce the risks that the routing protocol will reach a concave node in the network. Our simulation results show that PARA’s performance is better in sparse networks with little congestion. Moreover, PARA significantly outperforms GPSR for delivery ratio, transmission delay and path length. Our results also indicate that PARA delivers more packets than AODV under the same conditions.

  16. Integrated Routing Protocol for Opportunistic Networks

    Directory of Open Access Journals (Sweden)

    Anshul Verma

    2011-03-01

    Full Text Available In opportunistic networks the existence of a simultaneous path is not assumed to transmit a message between a sender and a receiver. Information about the context in which the users communicate is a key piece of knowledge to design efficient routing protocols in opportunistic networks. But this kind of information is not always available. When users are very isolated, context information cannot be distributed, and cannot be used for taking efficient routing decisions. In such cases, context oblivious based schemes are only way to enable communication between users. As soon as users become more social, context data spreads in the network, and context based routing becomes an efficient solution. In this paper we design an integrated routing protocol that is able to use context data as soon as it becomes available and falls back to dissemination-based routing when context information is not available. Then, we provide a comparison between Epidemic and PROPHET, these are representative of context oblivious and context aware routing protocols. Our results show that integrated routing protocol is able to provide better result in term of message delivery probability and message delay in both cases when context information about users is available or not.

  17. Routing problems based on hils system platform

    Directory of Open Access Journals (Sweden)

    Andrzej Adamski

    2015-03-01

    Full Text Available Background: The logistic systems are very complex socio-technical systems. In this paper the proposal of application of the hierarchical multi-layers system platform HILS approach for the solution of the complex vehicle routing problems is presented. The interactive system functional structure was proposed which by intelligent dedicated inter-layers interactions enables the professional solutions of these practical problems. To illustrate these capabilities the complex example of the real-time VRP-SPD-TW routing problem was presented in which upper layers offers the context-related real-time updating network specifications that stimulates the adequate routing parameters and specifications updating for problem solution in optimization layer. At the bottom dispatching control layer the DISCON (Dispatching CONtrol method from public transport was adopted to logistics applications in which the actual routing is treated as obligatory reference schedule to be stabilized. The intelligence aspects are related among others to HILS based decomposition, context-related trade-offs between routing modifications and corrective dispatching control capabilities e.g. priority or route guidance actions. Methods: Decomposition of the vehicle routing problem for the HILS layers tasks creating the ILS system hierarchical structure. Dedicated solution method for the VRP-SPD-TW routing problem. The recognition of the control preferences structure by AHP-Entropy methods. DISCON and PIACON multi-criteria interacting control methods. Results: Original formulation and solution of the vehicle routing problem by system-wide approach with essential practical advantages: consistency, lack of redundancy, essential reduction of dimension, dedicated formulation, multi-criteria approach, exploration of the integration and intelligence features supported by the intelligent PIACON-DISCON methods control activities Conclusions: The presented proposal creates the professional

  18. Agent routing algorithm in wireless sensor networks

    Science.gov (United States)

    Zhang, Yuqing; Yang, Shuqun

    2013-03-01

    Wireless sensor networks are a new technology of information acquisition and processing, so they are widely used in all kinds of fields. In the paper we introduce Agent technology into the wireless sensor network, conduct a in-depth research on the four routing schemes, and propose a new improved routing scheme, which considers the energy consumption of both nodes and path. Furthermore, The scheme we proposed has efficient routing function, can balance the energy consumption of nodes and extends the lifetime of the network in a more efficient way.

  19. Dynamic telecast Routing with Security Intensification

    Directory of Open Access Journals (Sweden)

    BeerthiSahadev

    2011-09-01

    Full Text Available Security has become one of the majorissues for data communication over wired and wireless networks. Different from the past work on the designs of network security algorithms and system infrastructures, we will propose a dynamic broadcast routing algorithm that could randomize delivery paths for data transmission. The algorithm is easy to implement and compatible with popular routing protocols, such as the Routing Information Protocol in wired networks and Destination-Sequenced Distance Vector protocol in wireless networks , without introducing extra control messages. The simulation results have been verified from the proposed algorithm and it shows the capability of the proposed algorithm.

  20. Navigation Assistance: A Trade-Off between Wayfinding Support and Configural Learning Support

    Science.gov (United States)

    Munzer, Stefan; Zimmer, Hubert D.; Baus, Jorg

    2012-01-01

    Current GPS-based mobile navigation assistance systems support wayfinding, but they do not support learning about the spatial configuration of an environment. The present study examined effects of visual presentation modes for navigation assistance on wayfinding accuracy, route learning, and configural learning. Participants (high-school students)…

  1. LOTIR: A Routing Protocol for Multi-hop V-to-I Communication Using Local Traffic Information

    Directory of Open Access Journals (Sweden)

    Kun-chan Lan

    2012-08-01

    Full Text Available Vehicular Ad Hoc Network (VANET is an emerging technology that can be applied to safety, transport efficiency, or infotainment applications for roads and highways. However, due to its unique features, such as dynamic mobility patterns and uneven distributions of vehicles, VANET faces many challenging research issues for robust data dissemination in the network. Many routing protocols have been proposed for VANET in the past few years, and the idea of utilizing a navigation system to assist the routing protocol for selecting the next best forwarder has become increasingly popular. However, it might not be realistic to assume that every vehicle is equipped with a navigation system. In addition, due to privacy concerns, drivers might not want to reveal their planned routes to other cars. In this work, we propose a new routing protocol, called LOTIR (LOcal Traffic Information Routing, that relies on only local traffic information and does not require the assistance of a navigation system. LOTIR is a DTN-based routing protocol that utilizes the car-following theory and traffic light information to decide the next carrier to forward the data to. We implement LOTIR in NS-2, and our results show that it can achieve similar performance as prior work which depends on the availability of global network topology information.

  2. Efficient Synthesis of Spirobarbiturates and Spirothiobarbiturates Bearing Cyclopropane Rings by Rhodium(II)-Catalyzed Reactions of Cyclic Diazo Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xue; Lee, Yong Rok [Yeungnam Univ., Gyeongsan (Korea, Republic of)

    2013-06-15

    Rhodium(II)-catalyzed reactions of cyclic diazo compounds derived from barbituric acid and thiobarbituric acid with a variety of styrene moieties were examined. These reactions provide rapid synthetic routes to the preparations of spirobarbiturates and spirothiobarbiturates bearing cyclopropane rings.

  3. History-based route selection for reactive ad hoc routing protocols

    Science.gov (United States)

    Medidi, Sirisha; Cappetto, Peter

    2007-04-01

    Ad hoc networks rely on cooperation in order to operate, but in a resource constrained environment not all nodes behave altruistically. Selfish nodes preserve their own resources and do not forward packets not in their own self interest. These nodes degrade the performance of the network, but judicious route selection can help maintain performance despite this behavior. Many route selection algorithms place importance on shortness of the route rather than its reliability. We introduce a light-weight route selection algorithm that uses past behavior to judge the quality of a route rather than solely on the length of the route. It draws information from the underlying routing layer at no extra cost and selects routes with a simple algorithm. This technique maintains this data in a small table, which does not place a high cost on memory. History-based route selection's minimalism suits the needs the portable wireless devices and is easy to implement. We implemented our algorithm and tested it in the ns2 environment. Our simulation results show that history-based route selection achieves higher packet delivery and improved stability than its length-based counterpart.

  4. Performance Analysis of Route Discovery by Cross Layer Routing Protocol- RDCLRP

    Directory of Open Access Journals (Sweden)

    Mehajabeen Fatima

    2013-06-01

    Full Text Available Wired and wireless network is based on the TCP / IP architecture but it is not sufficient to cope with the dynamics of the MANET. Cross layer design can be an alternative architecture for MANET. Frequent route break is one of the major problems of mobile adhoc network (MANET. Path breaks due to less available battery power and mobility of nodes. Most of the battery power is consumed in flooding of control packets. A key challenge in the design of efficient routing protocol is to reduce link breakage and flooding of control packets. Route breakage can be reduced if the possibility of route breakage is predicted and a handoff is done without drop of data packets. If route breakage is reduced, the more battery power will be available with nodes. In turn it reduces the possibility of route breakage and the possibility of flooding. This is a cumulative effect. So a novel preemptive route repair algorithm is proposed named as RDCLRP- Route discovery by cross layer routing protocol to reduce frequency of control packet flooding and route breakage. Three variants of RDCLRP and their results are illustrated. In this paper, the impact of the number of nodes on performance of RDCLRP are investigated and analyzed. The results show 55.6% reduction in link breakage, 14.7% improvement in residual battery power and an average of 6.7% increase in throughput compared to basic AODV.

  5. Nuclear Many-Body Physics Where Structure And Reactions Meet

    OpenAIRE

    Ahsan, Naureen; Volya, Alexander

    2009-01-01

    The path from understanding a simple reaction problem of scattering or tunneling to contemplating the quantum nuclear many-body system, where structure and continuum of reaction-states meet, overlap and coexist, is a complex and nontrivial one. In this presentation we discuss some of the intriguing aspects of this route.

  6. Advances in technology for integrated route analysis

    Energy Technology Data Exchange (ETDEWEB)

    Carey, N.T.; George, P.J.; Khamhawi, K. [SAGE Engineering Ltd., Bath (United Kingdom)

    1998-12-31

    Pipeline and cable routes are becoming ever complex with routes being chosen in increasingly remote and technically demanding areas. Clients now demand greater information and analysis from the surveys and interpretations. By utilising a range of leading edge equipment, greater information can be obtained, visualised and analysed than ever before. Three case studies are presented, indicating how such technology has been employed to provide the client with a greater understanding of complex engineering projects, and what additional technology could have been utilised to further enhance the project. Examples of data, systems and project management used on two major pipe routes and one major cable route are presented. Swath Bathymetry (ISIS), 3D visualisation (Fledermaus), cone penetrometer testing (SAGE Miniature CPT), GIS databases (INfoXProfessional), and the use of pipeline stress analysis, upheaval buckling and rock dump optimisation software (SAFE Profile) are all examined. (author)

  7. Statistical Analysis to Select Evacuation Route

    Science.gov (United States)

    Musyarof, Z.; Sutarto, D. Y.; Atika, D. R.; Fajriya Hakim, R. B.

    2015-06-01

    Each country should be responsible for the safety of people, especially responsible for the safety of people living in disaster-prone areas. One of those services is provides evacuation route for them. But all this time, the selection of evacuation route is seem does not well organized, it could be seen that when a disaster happen, there will be many accumulation of people on the steps of evacuation route. That condition is dangerous to people because hampers evacuation process. By some methods in Statistical analysis, author tries to give a suggestion how to prepare evacuation route which is organized and based on people habit. Those methods are association rules, sequential pattern mining, hierarchical cluster analysis and fuzzy logic.

  8. On line routing per mobile phone

    DEFF Research Database (Denmark)

    Bieding, Thomas; Görtz, Simon; Klose, Andreas

    2009-01-01

    On-line routing is concerned with building vehicle routes in an ongoing fashion in such a way that customer requests arriving dynamically in time are efficiently and effectively served. An indispensable prerequisite for applying on-line routing methods is mobile communication technology....... Additionally it is of utmost importance that the employed communication system is suitable integrated with the firm’s enterprise application system and business processes. On basis of a case study, we describe in this paper a system that is cheap and easy to implement due to the use of simple mobile phones....... Additionally, we address the question how on-line routing methods can be integrated in this system....

  9. Integrating routing decisions in public transportation problems

    CERN Document Server

    Schmidt, Marie E

    2014-01-01

    This book treats three planning problems arising in public railway transportation planning: line planning, timetabling, and delay management, with the objective to minimize passengers’ travel time. While many optimization approaches simplify these problems by assuming that passengers’ route choice is independent of the solution, this book focuses on models which take into account that passengers will adapt their travel route to the implemented planning solution. That is, a planning solution and passengers’ routes are determined and evaluated simultaneously. This work is technically deep, with insightful findings regarding complexity and algorithmic approaches to public transportation problems with integrated passenger routing. It is intended for researchers in the fields of mathematics, computer science, or operations research, working in the field of public transportation from an optimization standpoint. It is also ideal for students who want to gain intuition and experience in doing complexity proofs ...

  10. Language and Spatial Cognition in Route Navigation

    Institute of Scientific and Technical Information of China (English)

    宋娟

    2013-01-01

    The purpose of this study is to investigate the contrast between using street names or landmarks to process spatial in⁃structions. The study confirms the special cognitive status of landmarks in the mental representation of routes.

  11. IPv6 Network Mobility Route Optimization Survey

    Directory of Open Access Journals (Sweden)

    Samer S. Hassan

    2011-01-01

    Full Text Available Problem statement: This study describes that the Next Generation of Networks (NGN communication will supports multiple technologies, handles the mobility of end users to move through heterogeneous access networks, with ability to connect to different networks. Where the Internet Engineer Task Force maintain (IETF the Mobile IPv6 (MIPv6 to handles the mobility of networks (NEMO, to provide wide band and more scalable network services. One of the MIPv6 built-in features is Route Optimization (RO to solve the inefficient route problem. Conclusion/Recommendations: The main objective of this article is to survey, classify and make a compression between the available schemes for route optimization over the last years depends on the basic criteria generated from the published articles within different network topology. This article presents the problem of suboptimal route which is further increased with increasing of nesting levels and there is no such one scheme is perfect for all network environments.

  12. Rich Vehicle Routing Problems and Applications

    DEFF Research Database (Denmark)

    Wen, Min

    given set of customers. The VRP is a computationally hard combinatorial problem and has been intensively studied by numerous researchers in the last fifty years. Due to the significant economic benefit that can be achieved by optimizing the routing problems in practice, more and more attention has been......The Vehicle Routing Problem (VRP) is one of the most important and challenging optimization problems in the field of Operations Research. It was introduced by Dantzig and Ramser (1959) and defined as the problem of designing the optimal set of routes for a fleet of vehicles in order to serve a...... problems in the sense that consolidation decisions have to be made at the depot and these decisions interact with the planning of pickup and delivery routes. We presented a mathematical model and proposed a Tabu Search based heuristic to solve it. It is shown that the approach can produce near-optimal...

  13. An Anonymous Secure Routing Using OLSR Protocol

    Directory of Open Access Journals (Sweden)

    Osiers Gyamfuah Grace

    2013-01-01

    Full Text Available Security and privacy concerns are major issues to be considered in Mobile Ad hoc Networking (MANET. Several routing protocols have been proposed to achieve both routing and data packets security. In order to achieve privacy, the anonymous routing concept has been introduced and few protocols have been proposed for use in this area. In this paper, global position system (GPS device is used to obtain the current location of nodes and with the help of a cryptographic algorithm incorporated into the existing Optimized Link State Routing protocol (OLSR, it is expected that security services such as authentication, data integrity, privacy and confidentiality will be provided. This work proposes to protect the network against active attacks such as impersonation and modification.

  14. Latent factors and route choice behaviour

    DEFF Research Database (Denmark)

    Prato, Carlo Giacomo

    A behaviourally realistic description of the route choice process should consider variables that are both observable, such as travel time and cost, and unobservable, such as attitudes, perceptions, spatial abilities and network knowledge. This manuscript focuses on automotive route choice behaviour....... A reliable dataset was prepared through measures of internal consistency and sampling adequacy, and data were analyzed with a proper application of factor analysis to the route choice context. For the dataset obtained from the survey, six latent constructs affecting driver behaviour were extracted and scores...... on each factor for each survey participant were calculated. Path generation algorithms were examined with respect to observed behaviour, through a measure of reproduction with deterministic techniques of the routes indicated in the answers to the survey. Results presented evidence that the majority...

  15. Multicriteria Evolutionary Weather Routing Algorithm in Practice

    Directory of Open Access Journals (Sweden)

    Joanna Szlapczynska

    2013-03-01

    Full Text Available The Multicriteria Evolutionary Weather Routing Algorithm (MEWRA has already been introduced by the author on earlier TransNav 2009 and 2011 conferences with a focus on theoretical application to a hybrid-propulsion or motor-driven ship. This paper addresses the topic of possible practical weather routing applications of MEWRA. In the paper some practical advantages of utilizing Pareto front as a result of multicriteria optimization in case of route finding are described. The paper describes the notion of Pareto-optimality of routes along with a simplified, easy to follow, example. It also discusses a choice of the most suitable ranking method for MEWRA (a comparison between Fuzzy TOPSIS and Zero Unitarization Method is presented. In addition to that the paper briefly outlines a commercial application of MEWRA.

  16. Dams and Obstructions along Iowa's Canoe Routes

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This dataset represents obstruction to canoe and boat users of the canoe routes of Iowa. This may represent actual dams, rock dams (natural or man made), large...

  17. A Multistage Method for Multiobjective Route Selection

    Science.gov (United States)

    Wen, Feng; Gen, Mitsuo

    The multiobjective route selection problem (m-RSP) is a key research topic in the car navigation system (CNS) for ITS (Intelligent Transportation System). In this paper, we propose an interactive multistage weight-based Dijkstra genetic algorithm (mwD-GA) to solve it. The purpose of the proposed approach is to create enough Pareto-optimal routes with good distribution for the car driver depending on his/her preference. At the same time, the routes can be recalculated according to the driver's preferences by the multistage framework proposed. In the solution approach proposed, the accurate route searching ability of the Dijkstra algorithm and the exploration ability of the Genetic algorithm (GA) are effectively combined together for solving the m-RSP problems. Solutions provided by the proposed approach are compared with the current research to show the effectiveness and practicability of the solution approach proposed.

  18. Stochastic vehicle routing: from theory to practice

    OpenAIRE

    Weyland, Dennis; Gambardella, Luca Maria; Montemanni, Roberto

    2013-01-01

    In this thesis we discuss practical and theoretical aspects of various stochastic vehicle routing problems. These are combinatorial optimization problems related to the field of transportation and logistics in which input data is (partially) represented in a stochastic way. More in detail, we focus on two-stage stochastic vehicle routing problems and in particular on so-called a priori optimization problems. The results are divided into a theoretical part and a practical part. In fact, the ...

  19. Southern Bohemian route of industrial heritage

    OpenAIRE

    Vladimír Dvořák; Blažena Gehinová; Dagmar Škodová Parmová; Eva Jaderná; Eduard Šitler

    2009-01-01

    This paper deals with the industrial heritage and its usage in the frame of tourism service supply. There were three so called Anchor Points selected based on the ERIH methodology in the southern Bohemia. And there were also other regional and important places and points named for the future tourist route. The Southern Bohemian Route of Industrial Heritage was invented around the Anchor Point of Schwarzenberg Channel because of its importance in European heritage and its location next to the ...

  20. ETOR-Efficient Token based Opportunistic Routing

    OpenAIRE

    A. Saichand; Naseer, A. R.

    2013-01-01

    This paper proposes an Efficient Token based Opportunistic Routing called ETOR, which is animprovement to the token based coordination approach for opportunistic routing proposed by Economy[1].In Economy, method used for finding the connected candidate order chooses neighbor as the nextcandidate by considering ETX of that neighbor towards the source but it does not consider the linkprobability between the relay candidate and neighbor to be selected. ETOR proposes variant methods forfinding th...

  1. Hybrid Routing in Delay Tolerant Networks

    OpenAIRE

    Mayer, Christoph P.

    2012-01-01

    This work addresses the integration of today\\'s infrastructure-based networks with infrastructure-less networks. The resulting Hybrid Routing System allows for communication over both network types and can help to overcome cost, communication, and overload problems. Mobility aspect resulting from infrastructure-less networks are analyzed and analytical models developed. For development and deployment of the Hybrid Routing System an overlay-based framework is presented.

  2. A CONTRIBUTION TO SECURE THE ROUTING PROTOCOL

    Directory of Open Access Journals (Sweden)

    Mohammed ERRITALI

    2011-10-01

    Full Text Available This work presents a contribution to secure the routing protocol GPSR (Greedy Perimeter StatelessRouting for vehicular ad hoc networks, we examine the possible attacks against GPSR and securitysolutions proposed by different research teams working on ad hoc network security. Then, we propose asolution to secure GPSR packet by adding a digital signature based on symmetric cryptographygenerated using the AES algorithm and the MD5 hash function more suited to a mobile environment

  3. A CONTRIBUTION TO SECURE THE ROUTING PROTOCOL

    OpenAIRE

    Mohammed ERRITALI; Oussama Mohamed Reda; Bouabid El Ouahidi

    2011-01-01

    This work presents a contribution to secure the routing protocol GPSR (Greedy Perimeter StatelessRouting) for vehicular ad hoc networks, we examine the possible attacks against GPSR and securitysolutions proposed by different research teams working on ad hoc network security. Then, we propose asolution to secure GPSR packet by adding a digital signature based on symmetric cryptographygenerated using the AES algorithm and the MD5 hash function more suited to a mobile environment

  4. Integrated Routing Protocol for Opportunistic Networks

    OpenAIRE

    Anshul Verma; Dr. Anurag Srivastava

    2012-01-01

    In opportunistic networks the existence of a simultaneous path is not assumed to transmit a message between a sender and a receiver. Information about the context in which the users communicate is a key piece of knowledge to design efficient routing protocols in opportunistic networks. But this kind of information is not always available. When users are very isolated, context information cannot be distributed, and cannot be used for taking efficient routing decisions. In such cases, context o...

  5. Ising model for packet routing control

    International Nuclear Information System (INIS)

    For packet routing control in computer networks, we propose an Ising model which is defined in order to express competition among a queue length and a distance from a node with a packet to its destination node. By introducing a dynamics for a mean-field value of an Ising spin, we show by computer simulations that effective control of packet routing through priority links is possible

  6. Low Carbon Footprint Routes for Bird Watching

    OpenAIRE

    Wei-Ta Fang; Chin-Wei Huang; Jui-Yu Chou; Bai-You Cheng; Shang-Shu Shih

    2015-01-01

    Bird watching is one of many recreational activities popular in ecotourism. Its popularity, therefore, prompts the need for studies on energy conservation. One such environmentally friendly approach toward minimizing bird watching’s ecological impact is ensuring a reduced carbon footprint by using an economic travel itinerary comprising a series of connected routes between tourist attractions that minimizes transit time. This study used a travel-route planning approach using geographic info...

  7. Security Conformance for the Dynamically Routed Data

    OpenAIRE

    Suma Patra; Dr.V.Janaki; Priyanka suram; Nalubala Ranjeeth Kumar

    2011-01-01

    Secure transmission of data plays a crucial role in the networks. To improve the security many methodologies have been proposed till now, like cryptographic designs, intrusion detection, dynamic routing etc. In this paper we consider that the data transmission is done by using the concept of dynamic routing. Sometimes the sender may be neglecting the security due to the lack of personal interest, but the receiver has to take the utmost care. In such cases the receiver after forcing the sender...

  8. Improved Multispanning Tree Routing Using Efficient and Reliable Routing Algorithm for Irregular Networks

    Directory of Open Access Journals (Sweden)

    L. Keerthana

    2012-06-01

    Full Text Available A Strategy of Multispanning Tree Zone Ordered Label Based routing is improved with Efficient and Reliable (EAR routing for irregular networks is presented and analyzed in this work. Most existing deadlock free routing methods for irregular topologies impose several limitations on node and channel labeling in an irregular network is based on a pre-defined spanning tree.It is not possible to form a deadlock free zone of three or four channel labels for two spanning tree. So this existing Multispanning Tree Zone Ordered Label Based routing is modified with Efficient and Reliable (EAR routing. EAR is based on four parameters length of the path,distance traversed,transmission of link and energy levels to dynamically determine and maintain the best routes.. The simulation results have shown highest packet delivery ratio, minimum latency, and energy consumption.

  9. Shape-controlled synthesis and properties of manganese sulfide microcrystals via a biomolecule-assisted hydrothermal process

    International Nuclear Information System (INIS)

    An effective biomolecule-assisted synthetic route has been successfully developed to prepare γ-manganese sulfide (MnS) microtubes under hydrothermal conditions. In the synthetic system, soluble hydrated manganese chloride was employed to supply Mn source and L-cysteine was used as precipitator and complexing reagent. Sea urchin-like γ-MnS and octahedron-like α-MnS microcrystals could also be selectively obtained by adjusting the process parameters such as hydrothermal temperature and reaction time. The phase structures, morphologies and properties of the as-prepared products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and photoluminescence spectra (PL). The photoluminescence studies exhibited the correlations between the morphology, size, and shape structure of MnS microcrystals and its optical properties. The formation mechanisms of manganese sulfide microcrystals were discussed based on the experimental results.

  10. Multirate Anypath Routing in Wireless Mesh Networks

    CERN Document Server

    Laufer, Rafael

    2008-01-01

    In this paper, we present a new routing paradigm that generalizes opportunistic routing in wireless mesh networks. In multirate anypath routing, each node uses both a set of next hops and a selected transmission rate to reach a destination. Using this rate, a packet is broadcast to the nodes in the set and one of them forwards the packet on to the destination. To date, there is no theory capable of jointly optimizing both the set of next hops and the transmission rate used by each node. We bridge this gap by introducing a polynomial-time algorithm to this problem and provide the proof of its optimality. The proposed algorithm runs in the same running time as regular shortest-path algorithms and is therefore suitable for deployment in link-state routing protocols. We conducted experiments in a 802.11b testbed network, and our results show that multirate anypath routing performs on average 80% and up to 6.4 times better than anypath routing with a fixed rate of 11 Mbps. If the rate is fixed at 1 Mbps instead, p...

  11. ACO Agent Based Routing in AOMDV Environment

    Directory of Open Access Journals (Sweden)

    Kaur Amanpreet

    2016-01-01

    Full Text Available Mobile Ad-hoc Network (MANET is a group of moving nodes which can communicate with each other without the help of any central stationary node. All the nodes in the MANET act as router for forwarding data packets. The nodes in the network also move randomly and there exists no fixed infrastructure. So, path breaks are the frequent problem in MANET. The routing protocol faces a lot of problem due these path breaks. Therefore, the routing protocol which is multipath in nature is more reliable than a unipath routing protocol. Ant colony optimization is a relatively new technique which is suitable for the optimization problems. AOMDV is a multipath routing protocol. Thus, if there happens to be path break, the packets can start following the new path which has already been selected. In this paper, we are trying to add ant’s agents into AOMDV behavior. In this way, the new protocol will be benefited by the dual properties i.e. of ant’s nature and multipath nature of AOMDV. The modified concept is simulated and the outcomes are compared with AOMDV, AODV and DSR routing protocols for few performance parameters. Results obtained are encouraging; the new algorithm performs better than traditional unipath and multipath routing protocols.

  12. The Route Analysis Based On Flight Plan

    Science.gov (United States)

    Feriyanto, Nur; Saleh, Chairul; Fauzi, Achmad; Rachman Dzakiyullah, Nur; Riza Iwaputra, Kahfi

    2016-02-01

    Economic development effects use of air transportation since the business process in every aspect was increased. Many people these days was prefer using airplane because it can save time and money. This situation also effects flight routes, many airlines offer new routes to deal with competition. Managing flight routes is one of the problems that must be faced in order to find the efficient and effective routes. This paper investigates the best routes based on flight performance by determining the amount of block fuel for the Jakarta-Denpasar flight route. Moreover, in this work compares a two kinds of aircraft and tracks by calculating flight distance, flight time and block fuel. The result shows Jakarta-Denpasar in the Track II has effective and efficient block fuel that can be performed by Airbus 320-200 aircraft. This study can contribute to practice in making an effective decision, especially helping executive management of company due to selecting appropriate aircraft and the track in the flight plan based on the block fuel consumption for business operation.

  13. Grid data extraction algorithm for ship routing

    Science.gov (United States)

    Li, Yuankui; Zhang, Yingjun; Yue, Xingwang; Gao, Zongjiang

    2015-05-01

    With the aim of extracting environmental data around routes, as the basis of ship routing optimization and other related studies, this paper, taking wind grid data as an example, proposes an algorithm that can effectively extract the grid data around rhumb lines. According to different ship courses, the algorithm calculates the wind grid index values in eight different situations, and a common computational formula is summarised. The wind grids around a ship route can be classified into `best-fitting' grids and `additional' grids, which are stored in such a way that, for example, when the data has a high-spacing resolution, only the `best-fitting' grids around ship routes are extracted. Finally, the algorithm was implemented and simulated with MATLAB programming. As the simulation results indicate, the algorithm designed in this paper achieved wind grid data extraction in different situations and further resolved the extraction problem of meteorological and hydrogeological field grids around ship routes efficiently. Thus, it can provide a great support for optimal ship routing related to meteorological factors.

  14. Route selection issues for NWPA shipments

    International Nuclear Information System (INIS)

    Questions surrounding the designation of routes for the movement of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) by the Office of Civilian Radioactive Waste Management (OCRWM) have broad implications. Federal regulations prescribe rules to be applied in the selection of highway routes. In most cases, these rules will lead to a clear selection of one route between an origin and destination point. However, in other cases, strict application of the regulations does not result in a clear choice of a preferred route. The regulations also provide discretion to State governments and carriers to select alternative routes to enhance the safety of the shipment. Railroad shipments of radioactive materials are not subject to Federal routing regulations. Since the railroads operate on private property, it has been assumed that they know the best way to move freight on their system. This discretion, while desirable for addressing unique local safety concerns or for responding to temporary safety concerns such as road problems, weather conditions, or construction areas, leads to significant opportunity for misunderstandings and uneasiness on the part of local residents

  15. Manet Load Balancing Parallel Routing Protocol

    Directory of Open Access Journals (Sweden)

    Hesham Arafat Ali

    2012-07-01

    Full Text Available In recent years, multi-path routing protocols have attained more attention in mobile ad hoc networks as compared to other routing schemes due to their abilities and efficiency in improving bandwidth of communication, increasing delivery reliability, responding to congestion and heavy traffic. Several protocols have been developed to address multi path routing, but it always has a problem that the discovered paths may be not 100% disjoint and sending data is done in only one path until it's broken; the discovery of multiple paths also generates more overhead on the network. Load Balancing Parallel Routing Protocol [LBPRP] tried to solve previous multi path problems, distributing traffic among multiple paths sending data in parallel form as it uses all paths in the same time. We employed a simple test scenario to be sure of proposed model efficiency and to validate the proposed Load Balancing Parallel Routing Protocol. [LBPRP] will achieve load balancing in sending data, decreasing the end-to-end delay and increasing the packet delivery ratio and throughput, thus the performance of multi-path routing protocols can be improved consequently.

  16. Production of zinc substituted hydroxyapatite using various precipitation routes

    International Nuclear Information System (INIS)

    Substituted hydroxyapatites have been investigated for use as bone grafts and have been investigated for many years. Zinc is of interest due to its potential to reduce bone resorption and antibacterial properties. However, it has proven problematic to substitute biologically significant levels of zinc into the crystal structure through wet chemical routes, whilst retaining the high temperature phase stability required for processing. The aim of this study is to investigate two different precipitation routes used to synthesize zinc substituted hydroxyapatite and to explore the effects of ammonia used in the reactions on the levels of zinc substituted into the crystal lattice. It was found that considerable amounts of ammonia are required to maintain a pH sufficiently high for the production of stoichiometric hydroxyapatite using a reaction between calcium nitrate, zinc nitrate and ammonium phosphate. X-ray fluorescence analysis showed that a significant proportion of the zinc added did not substitute into the hydroxyapatite lattice. Fourier transform infrared spectroscopy revealed the existence of a zinc-ammonia complex that, it is proposed, inhibits zinc substitution for calcium. It was found that by reacting orthophosphoric acid with calcium nitrate and zinc nitrate, the volume of ammonia required in the reaction was reduced and higher levels of zinc substitution were achieved, with up to 0.58 wt% incorporated into the hydroxyapatite lattice. The resulting products were found to be stoichiometric hydroxyapatite and did not appear to contain any extraneous calcium phosphate phases after heat treatment up to 1100 °C. X-ray diffraction and Rietveld analysis revealed that the effect of substituting zinc into the HA lattice was to decrease the a-lattice parameter whilst increasing the c-lattice. Transmission electron microscopy also showed that the incorporation of zinc reduced both the length and width of the precipitated crystals. (paper)

  17. A wavelength-switched time-slot routing scheme for wavelength-routed networks

    OpenAIRE

    Li, CY.; Li, GM; Wai, PKA; Li, VOK

    2004-01-01

    Optical time division multiplexing (OTDM) is an effective approach to improve the performance of wavelength-routed (WR) networks. Implementation of all-optical time-slot routing in OTDM-WR networks is difficult owing to the lack of practical optical buffer and sophisticated optical processing devices. In this paper, we proposed a wavelength-switched time-slot routing scheme that can be implemented with fast wavelength converters only. Simulation results demonstrate that the performance of the...

  18. Are GIS-modelled routes a useful proxy for the actual routes followed by commuters?

    OpenAIRE

    Dalton, Alice M; Jones, Andrew P.; Panter, Jenna; Ogilvie, David

    2014-01-01

    Active commuting offers the potential to increase physical activity among adults by being built into daily routines. Characteristics of the route to work may influence propensity to walk or cycle. Geographic information system (GIS) software is often used to explore this by modelling routes between home and work. However, if the validity of modelled routes depends on the mode of travel used, studies of environmental determinants of travel may be biased. We aimed to understand how well mod...

  19. Microwave assisted template synthesis of silver nanoparticles

    Indian Academy of Sciences (India)

    K J Sreeram; M Nidhin; B U Nair

    2008-12-01

    Easier, less time consuming, green processes, which yield silver nanoparticles of uniform size, shape and morphology are of interest. Various methods for synthesis, such as conventional temperature assisted process, controlled reaction at elevated temperatures, and microwave assisted process have been evaluated for the kind of silver nanoparticles synthesized. Starch has been employed as a template and reducing agent. Electron microscopy, photon correlation spectroscopy and surface plasmon resonance have been employed to characterize the silver nanoparticles synthesized. Compared to conventional methods, microwave assisted synthesis was faster and provided particles with an average particle size of 12 nm. Further, the starch functions as template, preventing the aggregation of silver nanoparticles.

  20. WEAMR — A Weighted Energy Aware Multipath Reliable Routing Mechanism for Hotline-Based WSNs

    Directory of Open Access Journals (Sweden)

    Ki-Hyung Kim

    2013-05-01

    Full Text Available Reliable source to sink communication is the most important factor for an efficient routing protocol especially in domains of military, healthcare and disaster recovery applications. We present weighted energy aware multipath reliable routing (WEAMR, a novel energy aware multipath routing protocol which utilizes hotline-assisted routing to meet such requirements for mission critical applications. The protocol reduces the number of average hops from source to destination and provides unmatched reliability as compared to well known reactive ad hoc protocols i.e., AODV and AOMDV. Our protocol makes efficient use of network paths based on weighted cost calculation and intelligently selects the best possible paths for data transmissions. The path cost calculation considers end to end number of hops, latency and minimum energy node value in the path. In case of path failure path recalculation is done efficiently with minimum latency and control packets overhead. Our evaluation shows that our proposal provides better end-to-end delivery with less routing overhead and higher packet delivery success ratio compared to AODV and AOMDV. The use of multipath also increases overall life time of WSN network using optimum energy available paths between sender and receiver in WDNs.

  1. Primary reactions of recoiling germanium atoms

    International Nuclear Information System (INIS)

    75Ge recoils are made using the (n,2n) reaction. By analogy with Si recoils, two divalent species are suggested as intermediates in the recoil-germane reaction, one formed by H abstraction and the other formed by insertion only. A series of moderator and competition experiments were conducted. Of the noble gases, Kr is the most efficient moderator at removing kinetic energy from the recoils. Xe has a special effect due to its low ionization potential. A reaction scheme is proposed with two routes to digermane, one from a hot neutral atom and the other from a positive ion. 8 figures

  2. Rapid Grafting of Azido-labeled Oligo(ethylene glycol)s onto an Alkynyl-terminated Monolayer on Non-oxidized Silicon via Microwave-assisted “Click” Reaction

    OpenAIRE

    Li, Yan; Wang, Jun; Cai, Chengzhi

    2011-01-01

    Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated non-oxidized silicon substrates via copper-catalyzed “click” reaction. The “clickable” monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data o...

  3. Geographic information based Replication and Drop Routing (GeoRaDR: A Hybrid Message Transmission Approach for DTNs

    Directory of Open Access Journals (Sweden)

    Dr. Santhi Kumaran

    2015-07-01

    Full Text Available Several approaches have been proposed to perform routing in Delay/Disruption Tolerant Networks (DTNs which has a random connectivity pattern. As the routing path from the source to destination will not be available always it results in low delivery ratio and high end-end delay. Most routing schemes are based on uncontrolled replication mechanisms like full flooding or spraying to explore the diversities in routing paths in order to reduce data transmission delay and reliable message delivery. These methods create redundancy of the data in the network and thus cause high resource consumption like bandwidth and storage. In this paper various replication mechanisms used in different routing schemes are reviewed and a novel Replication and Drop Routing mechanism controlled by the location information (Geo-coordinates & the velocity of the nodes dubbed as (GeoRaDR is proposed. With the assistance of the derived moving vector (i.e the direction and the distance between the encountered nodes with respect to the destination node and the number of nodes available in the forward progress region of the half plane of the candidate node, the replication, drop and routing decisions are made. Thus, GeoRaDR performs a knowledge based replication of messages reducing the problem of redundancy and buffer overflows, while handling the local maximum problem and increasing the link reliability.

  4. 超声辅助或无溶剂Claisen-Schmidt反应合成含胡椒环的吲哚查尔酮%A facile synthesis of 1,3-benzodioxole-bearing indole-based chalcone via ultrasound-assisted or solvent-free Claisen-Schmidt condensation reaction

    Institute of Scientific and Technical Information of China (English)

    李阳

    2014-01-01

    A structurally novel 1,3-benzodioxole-bearing indole-based chalcone,namely(E)-3-(benzo[d][1,3]dioxol-5-yl)-1-(2-chloro-1-(4-chlorobenzyl)-1H-indol-3-yl) prop-2-en-1-one(3) was synthesized,involving the ultrasound-assisted or solvent-free Claisen-Schmidt condensation reaction of 3-acetyl-2-chloro-1-(4-chlorobenzyl) indole and piperonaldehyde. The ultrasound-assisted Claisen-Schmidt condensation reaction was carried out using 1,4-dioxane as solvent and KOH as catalyst at room temperature to give the product 3 in 78%yield. Alternatively,the reaction could also be conducted under solvent-free condition by physical grinding in a mortar and pestle to obtain 3 in comparable yield of 75%. The two procedures offered easy access to 1,3-benzodioxole-bearing indole-based chalcone in short reaction time and good yield under mild conditions.%3-乙酰基-2-氯-1-(4-氯苄基)吲哚与胡椒醛通过超声辅助或无溶剂的Claisen-Schmidt缩合反应首次合成含胡椒环的吲哚查尔酮,即(E)-3-(5-胡椒基)-1-(2-氯-1-(4-氯苄基)-1H-3-吲哚查尔酮(3)。超声辅助的合成方法使用5%KOH作为催化剂,1,4-二氧六环作为溶剂,以78%的收率得到产品3。另外,这一 Claisen-Schmidt反应也可以在无溶剂研磨条件下进行,同样也以类似的收率获得产品3(75%)。这两种方法具有操作简便、反应条件温和、收率高等优点。

  5. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  6. Reaction mechanisms

    International Nuclear Information System (INIS)

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported

  7. Study on Reaction Mechanism for Cracking FCC Gasoline on Acid Catalyst

    Institute of Scientific and Technical Information of China (English)

    Xu Youhao; Wang Xieqing

    2004-01-01

    This article is based on the experimental data on reaction of FCC naphtha in the presence of acid catalysts. The data published in the literature were reprocessed and compared with experimental data and the relationship of hydrogen and methane contained in the dry gas with the conversion rate was identified.The similarity between the route for cracking of olefin enriched FCC gasoline and the route for reaction of individual hydrocarbons was deduced, while the route for formation of ethylene in dry gas was also proposed to identify the relationship between the reaction path for formation of ethylene and the conversion rate.

  8. Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki-Miyaura reactions: relative reactivity of K[4-RC6F4BF3] and the role of silver-assistance in acceleration of transmetallation.

    Science.gov (United States)

    Bardin, Vadim V; Shabalin, Anton Yu; Adonin, Nicolay Yu

    2015-01-01

    Small differences in the reactivity of weakly nucleophilic potassium aryltrifluoroborates are revealed in the silver-assisted Pd-catalyzed cross-coupling of K[4-RC6F4BF3] (R = H, Bu, MeO, EtO, PrO, iPrO, BuO, t-BuO, CH2=CHCH2O, PhCH2O, PhCH2CH2O, PhO, F, pyrazol-1-yl, pyrrol-1-yl, and indol-1-yl) with ArX (4-BrC6H4CH3, 4-IC6H4F and 3-IC6H4F). An assumed role of silver(I) compounds Ag m Y (Y = O, NO3, SO4, BF4, F) consists in polarization of the Pd-X bond in neutral complex ArPdL n X with the generation of the related transition state or formation of [ArPdL n ][XAg m Y] with a highly electrophilic cation and subsequent transmetallation with the weakly nucleophilic borate. Efficiency of Ag m Y as a polarizing agent decreases in order Ag2O > AgNO3 ≈ Ag2SO4 > Ag[BF4] > AgF. No clear correlation between the reactivity of K[4-RC6F4BF3] and substituent electron parameters, σI and σR°, of the aryl group 4-RC6F4 was found. PMID:26124862

  9. Anthemis xylopoda flowers aqueous extract assisted in situ green synthesis of Cu nanoparticles supported on natural Natrolite zeolite for N-formylation of amines at room temperature under environmentally benign reaction conditions.

    Science.gov (United States)

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Hatamifard, Arezo

    2015-12-15

    Zeolites, which are nontoxic, abundant, and cheap, are very promising supports for the design and preparation of new and environmentally benign catalysts. In this study, Cu nanoparticles (NPs) were immobilized on the surface of natural Natrolite zeolite by Anthemis xylopoda flowers aqueous extract as a reducing and stabilizing agent. Afterward, the catalytic performance of the prepared catalyst was investigated for N-formylation of amines at room temperature under environmentally benign reaction conditions. The catalyst could be reused at least 5 times without any decrease in activity. The advantages of the present protocol include the use of green catalyst, easy isolation of the products, reusability of catalyst, absence of nontoxic reagents, and excellent yield of the products. PMID:26319331

  10. THERMODYNAMIC ANALYSIS OF CO2 DIRECT HYDROGENATION REACTIONS

    Institute of Scientific and Technical Information of China (English)

    Cao Fahai; Liu Dianhua; Hou Qiushi; Fang Dingye

    2001-01-01

    CO2 hydrogenation is one of important routes for the activation and effective utilization of CO2. In this paper, eighteen CO2 direct hydrogenation reactions are listed and their reaction heats and equilibrium constants are calculated. On the assumption that the reactions of CO2 and H2 are in stoichiometric ratio and the amount of whole reactants is one mole, the equilibrium conversions of CO2 are obtained.

  11. PERFORMANCE EVALUATION OF VANETS ROUTING PROTOCOLS

    Directory of Open Access Journals (Sweden)

    Abduladhim Ashtaiwi

    2014-11-01

    Full Text Available Lately, the concept of VANETs (Vehicular Ad hoc Networks has gotten a huge attention as more wireless communication technologies becoming available. Such networkis expected to be one of the most valuable technology for improving efficiency and safety of the future transportation. Vehicular networks are characterized by high mobility nodes which pose many communication challenging problems. In vehicular networks, routing Collision Avoidance Messages (CAMs among vehicles is a key communication problem.Failure in routing CAMs to their intended destination within the time constraint can render these messages useless. Many routing protocols have been adapted for VANETs, such as DSDV (Destination Sequenced Distance Vector, AODV (Ad-hoc On demand Distance Vector, and DSR (Dynamic Source Routing. This work compares the performance of those routing protocols at different driving environments and scenarios created by using the mobility generator (VanetMobiSim and network simulator(NS2. The obtained results at different vehicular densities, speeds, road obstacles, lanes, traffic lights, and transmission ranges showed that on average AODV protocol outperforms DSR and DSDV protocols in packet delivery ratio and end-toend delay. However, at certain circumstances (e.g., at shorter transmission ranges DSR tends to have better performance than AODV and DSDV protocols.

  12. Service discovery with routing protocols for MANETs

    Science.gov (United States)

    Gu, Xuemai; Shi, Shuo

    2005-11-01

    Service discovery is becoming an important topic as its use throughout the Internet becomes more widespread. In Mobile Ad hoc Networks (MANETs), the routing protocol is very important because it is special network. To find a path for data, and destination nodes, nodes send packets to each node, creating substantial overhead traffic and consuming much time. Even though a variety of routing protocols have been developed for use in MANETs, they are insufficient for reducing overhead traffic and time. In this paper, we propose SDRP: a new service discovery protocol combined with routing policies in MANETs. The protocol is performed upon a distributed network. We describe a service by a unique ID number and use a group-cast routing policy in advertisement and request. The group-cast routing policy decreases the traffic in networks, and it is efficient to find destination node. In addition, the nodes included in the reply path also cache the advertisement information, and it means when each node finds a node next time, they can know where it is as soon as possible, so they minimize the time. Finally, we compare SDRP with both Flood and MAODV in terms of overload, and average delay. Simulation results show SDRP can spend less response time and accommodate even high mobility network environments.

  13. An Indirect Route for Ethanol Production

    Energy Technology Data Exchange (ETDEWEB)

    Eggeman, T.; Verser, D.; Weber, E.

    2005-04-29

    The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

  14. Fuzzy Optimized Metric for Adaptive Network Routing

    Directory of Open Access Journals (Sweden)

    Ahmad Khader Haboush

    2012-04-01

    Full Text Available Network routing algorithms used today calculate least cost (shortest paths between nodes. The cost of a path is the sum of the cost of all links on that path. The use of a single metric for adaptive routing is insufficient to reflect the actual state of the link. In general, there is a limitation on the accuracy of the link state information obtained by the routing protocol. Hence it becomes useful if two or more metrics can be associated to produce a single metric that can describe the state of the link more accurately. In this paper, a fuzzy inference rule base is implemented to generate the fuzzy cost of each candidate path to be used in routing the incoming calls. This fuzzy cost is based on the crisp values of the different metrics; a fuzzy membership function is defined. The parameters of these membership functions reflect dynamically the requirement of the incoming traffic service as well as the current state of the links in the path. And this paper investigates how three metrics, the mean link bandwidth, queue utilization and the mean link delay, can be related using a simple fuzzy logic algorithm to produce a optimized cost of the link for a certain interval that is more „precise‟ than either of the single metric, to solve routing problem .

  15. Eccentricity in Zone Routing Protocol for MANET

    Directory of Open Access Journals (Sweden)

    Mrs Komal Nair

    2012-06-01

    Full Text Available A Mobile Ad-Hoc Network (MANET is a decentralized network of autonomous mobile nodes, able to communicate with each other over wireless links. Due to the mobility of the nodes, the topology ofthe network changes spontaneously, therefore use of conventional routing tables maintained at fixed points (routers is not suggested. Such a network may operate in a standalone fashion. There are variousrouting protocols available for MANETs. The most popular ones are DSR, DSDV and ZRP .The zone routing protocol (ZRP is a hybrid routing protocol that proactively maintains routes within a localregion of the network. ZRP can be configured for a particular network through adjustment of a single parameter, the routing zone radius. In this paper, we address the issue of configuring the ZRP to providethe best performance for a particular network at any time with the concept of eccentricity. The results illustrate the important characteristics of different protocols based on their performance and thus suggest some improvements in the respective protocol. The tools used for the simulation are NS2 which is the main simulator, NAM (Network Animator and Tracegraph which is used for preparing the graphs from the trace files.

  16. Low Carbon Footprint Routes for Bird Watching

    Directory of Open Access Journals (Sweden)

    Wei-Ta Fang

    2015-03-01

    Full Text Available Bird watching is one of many recreational activities popular in ecotourism. Its popularity, therefore, prompts the need for studies on energy conservation. One such environmentally friendly approach toward minimizing bird watching’s ecological impact is ensuring a reduced carbon footprint by using an economic travel itinerary comprising a series of connected routes between tourist attractions that minimizes transit time. This study used a travel-route planning approach using geographic information systems to detect the shortest path, thereby solving the problems associated with time-consuming transport. Based on the results of road network analyses, optimal travel-route planning can be determined. These methods include simulated annealing (SA and genetic algorithms (GA. We applied two algorithms in our simulation research to detect which one is an appropriate algorithm for running carbon-routing algorithms at the regional scale. SA, which is superior to GA, is considered an excellent approach to search for the optimal path to reduce carbon dioxide and high gasoline fees, thereby controlling travel time by using the shortest travel routes.

  17. Alternative routes to olefins. Chances and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Meiswinkel, A.; Delhomme, C.; Ponceau, M. [Linde AG, Pullach (Germany)

    2013-11-01

    In the future, conventional raw materials which are used for the production of olefins will get shorter and more expensive and alternative raw materials and production routes will gain importance. Natural gas, coal, shale oil or bio-mass are potential sources for the production of olefins, especially ethylene and propylene, as major base chemicals. Several potential production routes were already developed in the past, but cost, energy and environmental considerations might make these unattractive or unfeasible in comparison to traditional processes (e.g. steam cracking). Other processes such as methanol to olefins processes were successfully developed and first commercial units are running. In addition, combination of traditional processes (e.g. coal/biomass gasification, Fischer-Tropsch and steam cracking) might enable new pathways. Besides, dehydration of ethanol is opening direct routes from biomass to 'green' ethylene. However, for these 'bio-routes', feedstock availability and potential land use conflict with food production (sugar cane, wheat,..) still need to be evaluated. finally, new oxidative routes, including processes such as oxidative coupling of methane or oxidative dehydrogenation, are still at an early development stage but present potential for future industrial applications. (orig.) (Published in summary form only)

  18. ADVERSE REACTIONS TO VACCINES AND WAYS OF ITS PREVENTION

    Directory of Open Access Journals (Sweden)

    Yelyseyeva I. V

    2011-04-01

    Full Text Available The overview concerns allergic reaction on vaccines and possible ways of increasing safety of immunization on basis of use of local specific immunotherapies (SIT experience, particularly the sublingual route. The use of chemically altered allergens, allergoids; alternative routes of administration, particularly the sublingual route; use of novel adjuvants, such as CpG oligonucleotides and mycobacterial vaccines; other approaches, such as allergenic peptides, relevant T-cell epitope peptide immunotherapy; DNA vaccination, recombinant and engineered allergens, chimeric molecules and combined therapy are all approaches that have yielded positive results to increase safety of SIT and improve its efficacy.

  19. Impact of adaptive intra cluster routing on energy efficiency

    International Nuclear Information System (INIS)

    Speed, size and cost are the basic driving forces that cause research thirst for researchers. These forces have given birth to Wireless Sensor Network (WSN) that is composed of small, cheap and power efficient sensor nodes. These sensor nodes are battery operated that causes need of energy efficient/aware routing for such type of networks. Traditionally there are two routing techniques used for routing Direct Routing and MultiHop Routing, but Energy Efficient Adaptive Cluster Routing (EEACR) technique is proposed in this research work that has increased the energy efficiency, network lifetime and packet delivery ratio when compared with MultiHop routing a traditional routing technique. EEACR is an improved version of Adaptive Intra Cluster Routing (AICR). Results show that EEACR is much better than MultiHop routing techniques. For simulation and verification of results TOSSIM simulator is used. (author)

  20. The cluster beam route to model catalysts and beyond.

    Science.gov (United States)

    Ellis, Peter R; Brown, Christopher M; Bishop, Peter T; Yin, Jinlong; Cooke, Kevin; Terry, William D; Liu, Jian; Yin, Feng; Palmer, Richard E

    2016-07-01

    The generation of beams of atomic clusters in the gas phase and their subsequent deposition (in vacuum) onto suitable catalyst supports, possibly after an intermediate mass filtering step, represents a new and attractive approach for the preparation of model catalyst particles. Compared with the colloidal route to the production of pre-formed catalytic nanoparticles, the nanocluster beam approach offers several advantages: the clusters produced in the beam have no ligands, their size can be selected to arbitrarily high precision by the mass filter, and metal particles containing challenging combinations of metals can be readily produced. However, until now the cluster approach has been held back by the extremely low rates of metal particle production, of the order of 1 microgram per hour. This is more than sufficient for surface science studies but several orders of magnitude below what is desirable even for research-level reaction studies under realistic conditions. In this paper we describe solutions to this scaling problem, specifically, the development of two new generations of cluster beam sources, which suggest that cluster beam yields of grams per hour may ultimately be feasible. Moreover, we illustrate the effectiveness of model catalysts prepared by cluster beam deposition onto agitated powders in the selective hydrogenation of 1-pentyne (a gas phase reaction) and 3-hexyn-1-ol (a liquid phase reaction). Our results for elemental Pd and binary PdSn and PdTi cluster catalysts demonstrate favourable combinations of yield and selectivity compared with reference materials synthesised by conventional methods. PMID:27152749

  1. A Hybrid Routing Algorithm Based on Ant Colony and ZHLS Routing Protocol for MANET

    Science.gov (United States)

    Rafsanjani, Marjan Kuchaki; Asadinia, Sanaz; Pakzad, Farzaneh

    Mobile Ad hoc networks (MANETs) require dynamic routing schemes for adequate performance. This paper, presents a new routing algorithm for MANETs, which combines the idea of ant colony optimization with Zone-based Hierarchical Link State (ZHLS) protocol. Ant colony optimization (ACO) is a class of Swarm Intelligence (SI) algorithms. SI is the local interaction of many simple agents to achieve a global goal. SI is based on social insect for solving different types of problems. ACO algorithm uses mobile agents called ants to explore network. Ants help to find paths between two nodes in the network. Our algorithm is based on ants jump from one zone to the next zones which contains of the proactive routing within a zone and reactive routing between the zones. Our proposed algorithm improves the performance of the network such as delay, packet delivery ratio and overhead than traditional routing algorithms.

  2. ACRR: Ad Hoc On-Demand Distance Vector Routing with Controlled Route Requests

    CERN Document Server

    Kataria, Jayesh; Sanyal, Sugata

    2010-01-01

    Reactive routing protocols like Ad Hoc On-Demand Distance Vector Routing (AODV) and Dynamic Source Routing (DSR)in Ad-Hoc Wireless Networks which are used in Mobile and Ad Hoc Networks (MANETs) work by flooding the network with control packets. There is generally a limit on the number of these packets that can be generated or forwarded. But a malicious node can disregard this limit and flood the network with fake control packets. These packets hog the limited bandwidth and processing power of genuine nodes in the network while being forwarded. Due to this, genuine route requests suffer and many routes either do not get a chance to materialize or they end up being longer than otherwise. In this paper we propose a non cryptographic solution to the above problem and prove its efficiency by means of simulation.

  3. A Review Paper on Route Maintenance in Stability Based Energy Aware Routing Protocol In MANET

    Directory of Open Access Journals (Sweden)

    Gaurav J. Bhatt*,

    2014-05-01

    Full Text Available Mobile Ad hoc Networks (MANETs are temporary formed, infrastructure-less networks. Due to the mobility in nature of mobile nodes, limited battery, congestion, as well as noise, the problem of link failure causes. The performance metrics degrades due to the unstable channel conditions, network connectivity, and mobility and resource limitations. The goal of this paper is to review papers that finds most reliable and energy aware route that is impervious to failures by topological changes by mobile node mobility or lack of energy and various route maintenance approaches in order to establish stable, long lasting route and reduce link failure and packet drops. Make before break mechanism used to achieve route maintenance that predicts link failure before it actually breaks and find alternate route towards destination to avoid unpredictable link failure. Performance increases by considering various parameters like signal strength, energy of node, congestion, noise instead of the minimum hop count approach of the default distance vector algorithm. Keywords -

  4. Routes visualization: Automated placement of multiple route symbols along a physical network infrastructure

    Directory of Open Access Journals (Sweden)

    Jules Teulade-Denantes

    2015-12-01

    Full Text Available This paper tackles the representation of routes carried by a physical network infrastructure on a map. In particular, the paper examines the case where each route is represented by a separate colored linear symbol offset from the physical network segments and from other routes—as on public transit maps with bus routes offset from roads. In this study, the objective is to automate the placement of such route symbols while maximizing their legibility, especially at junctions. The problem is modeled as a constraint optimization problem. Legibility criteria are identified and formalized as constraints to optimize, while focusing on the case of hiking routes in a physical network composed of roads and pedestrian paths. Two solving methods are tested, based on backtracking and simulated annealing meta-heuristics respectively. Encouraging results obtained on real data are presented and discussed.

  5. Research on secure routing algorithm in wireless sensor network

    Science.gov (United States)

    Zhang, Bo

    2013-03-01

    Through the research on the existing wireless sensor network (WSN) and its security technologies, this paper presents a design of the WSN-based secure routing algorithm. This design uses the existing routing algorithm as chief source, adding the security guidance strategy, introducing the location key information, to enhance the security performance of WSN routing. The improved routing algorithm makes the WSN routing achieve better anti-attack in the case of little overhead increase, therefore has high practical value.

  6. The commercial viability of the arctic shipping routes

    OpenAIRE

    Nilsen, Alexander

    2013-01-01

    It is commonly held that the Arctic Ocean and Arctic routes, presents an alternative to the traditional shipping routes through the Suez- and Panama- Channel, which is less time and cost consuming. This thesis strives to uncover weather or not this is the case by assessing the environmental developments, the distance and time characteristics of each defined route, as well as the individual costs associated with each route. The results from the alternative Arctic routes are then compared with ...

  7. The properties of route catchments in orbital - radial cities

    OpenAIRE

    Geoffrey Hyman; Les Mayhew

    2000-01-01

    In this paper we consider the analytical and geometric properties of route catchments in urban areas in which the transport network consists of a combination of radial routes converging on the city centre and one or more major orbital routes around the city. After defining the basic concepts, we examine in detail the analytical and geometric determination of quickest routes through the city centre versus orbital routing and how these vary with location, speed, and urban transport provision. T...

  8. Dynamics of hot-potato routing in IP networks

    OpenAIRE

    Teixeira, Renata; Shaikh, Aman; Griffin, Tim; Rexford, Jennifer

    2004-01-01

    Despite the architectural separation between intradomain and inter-domain routing in the Internet, intradomain protocols do influence the path-selection process in the Border Gateway Protocol (BGP). When choosing between multiple equally-good BGP routes, a router selects the one with the closest egress point, based on the intrado-main path cost. Under such hot-potato routing, an intradomain event can trigger BGP routing changes. To characterize the influ-ence of hot-potato routing, we conduct...

  9. MAP: Medial axis based geometric routing in sensor networks

    OpenAIRE

    Bruck, Jehoshua; Gao, Jie; Jiang, Anxiao

    2007-01-01

    One of the challenging tasks in the deployment of dense wireless networks (like sensor networks) is in devising a routing scheme for node to node communication. Important consideration includes scalability, routing complexity, quality of communication paths and the load sharing of the routes. In this paper, we show that a compact and expressive abstraction of network connectivity by the medial axis enables efficient and localized routing. We propose MAP, a Medial Axis based naming and routing...

  10. Evolution Strategies in the Multipoint Connections Routing

    Directory of Open Access Journals (Sweden)

    L. Krulikovska

    2010-09-01

    Full Text Available Routing of multipoint connections plays an important role in final cost and quality of a found connection. New algorithms with better results are still searched. In this paper, a possibility of using the evolution strategies (ES for routing is presented. Quality of found connection is evaluated from the view of final cost and time spent on a searching procedure. First, parametrical analysis of results of the ES are discussed and compared with the Prim’s algorithm, which was chosen as a representative of the deterministic routing algorithms. Second, ways for improving the ES are suggested and implemented. The obtained results are reviewed. The main improvements are specified and discussed in conclusion.

  11. Genetic algorithms for the vehicle routing problem

    Science.gov (United States)

    Volna, Eva

    2016-06-01

    The Vehicle Routing Problem (VRP) is one of the most challenging combinatorial optimization tasks. This problem consists in designing the optimal set of routes for fleet of vehicles in order to serve a given set of customers. Evolutionary algorithms are general iterative algorithms for combinatorial optimization. These algorithms have been found to be very effective and robust in solving numerous problems from a wide range of application domains. This problem is known to be NP-hard; hence many heuristic procedures for its solution have been suggested. For such problems it is often desirable to obtain approximate solutions, so they can be found fast enough and are sufficiently accurate for the purpose. In this paper we have performed an experimental study that indicates the suitable use of genetic algorithms for the vehicle routing problem.

  12. Predication-Based Intelligence Routing on Telecommunications

    Institute of Scientific and Technical Information of China (English)

    DONGJun; HEJifeng; PANYunhe

    2004-01-01

    The routingtelecommunication networksbeing one of key issues of management influences the switch rate and load balance directly, and becomes more and more important as the telecommunication traffic increases at full speed. It was said that raising one percent of switch rate of current Chinese telecommunication networks would result in revenue about one billion Yuan RMB. On the basis of demerit-analysis of routing scheme being used, a new intelligent routing strategy based on multi-agent systems and recurrent neural network predication is presented, including routing strategy, Calls generating and agent~ recurrent neural network computation, simulation software design, results and discussion. The results show that the new one is better by virtue of its upstanding distribution and intelligence characters, and provides excellent solution to increase network switch rate and balance network load. Meanwhile, its applications will go beyond the scope of telecommunication networks. But whether the strategy will be perfect depends on the cooperation among operator, manufacturer and researchers.

  13. Effective Privacy-Preserving Online Route Planning

    DEFF Research Database (Denmark)

    Ruiz Vicente, Carmen; Assent, Ira; Jensen, Christian Søndergaard

    An online Route Planning Service (RPS) computes a route from one location to another. Current RPSs such as Google Maps require the use of precise locations. However, some users may not want to disclose their source and destination locations due to privacy concerns. An approach that supplies fake...... locations to an existing service incurs a substantial loss of quality of service, and the service may well return a result that may be not helpful to the user. We propose a solution that is able to return accurate route planning results when source and destination regions are used in order to achieve...... privacy. The solution re-uses a standard online RPS rather than replicate this functionality, and it needs no trusted third party. The solution is able to compute the exact results without leaking of the exact locations to the RPS or un-trusted parties. In addition, we provide heuristics that reduce the...

  14. Towards Building an Intelligent Call Routing System

    Directory of Open Access Journals (Sweden)

    Thien Khai Tran

    2016-01-01

    Full Text Available This paper presents EduICR - an Intelligent Call Routing system. This system can route calls to the most appropriate agent using routing rules built by the text classifier. EduICR includes the following main components: telephone communication network; Vietnamese speech recognition; Text classifier/ Natural language processor and Vietnamese speech synthesis. To our best knowledge, this is one of the first systems in Vietnam to implement the integration mechanism of text processing and speech processing. This allows voice applications to be more intelligent, able to communicate with humans in natural language with high accuracy and reasonable speed. Having been built and tested in real environment, our system proves its accuracy attaining more than 95%.

  15. Generalized routing protocols for multihop relay networks

    KAUST Repository

    Khan, Fahd Ahmed

    2011-07-01

    Performance of multihop cooperative networks depends on the routing protocols employed. In this paper we propose the last-n-hop selection protocol, the dual path protocol, the forward-backward last-n-hop selection protocol and the forward-backward dual path protocol for the routing of data through multihop relay networks. The average symbol error probability performance of the schemes is analysed by simulations. It is shown that close to optimal performance can be achieved by using the last-n-hop selection protocol and its forward-backward variant. Furthermore we also compute the complexity of the protocols in terms of number of channel state information required and the number of comparisons required for routing the signal through the network. © 2011 IEEE.

  16. Dielectric Properties of CDS Nanoparticles Synthesized by Soft Chemical Route

    Indian Academy of Sciences (India)

    R Tripathi; A Kumar; T P Sinha

    2009-06-01

    CdS nanoparticles have been synthesized by a chemical reaction route using thiophenol as a capping agent. The frequency-dependent dielectric dispersion of cadmium sulphide (CdS) is investigated in the temperature range of 303–413 K and in a frequency range of 50 Hz–1 MHz by impedance spectroscopy. An analysis of the complex per-mittivity ( and ) and loss tangent (tan ) with frequency is performed by assuming a distribution of relaxation times. The scaling behaviour of dielectric loss spectra sug- gests that the relaxation describes the same mechanism at various temperatures. The frequency-dependent electrical data are analysed in the framework of conductivity and modulus formalisms. The frequency-dependent conductivity spectra obey the power law.

  17. The Porphobilinogen Conundrum in Prebiotic Routes to Tetrapyrrole Macrocycles

    Science.gov (United States)

    Taniguchi, Masahiko; Ptaszek, Marcin; Chandrashaker, Vanampally; Lindsey, Jonathan S.

    2016-05-01

    Attempts to develop a credible prebiotic route to tetrapyrroles have relied on enzyme-free recapitulation of the extant biosynthesis, but this process has foundered from the inability to form the pyrrole porphobilinogen (PBG) in good yield by self-condensation of the precursor δ-aminolevulinic acid (ALA). PBG undergoes robust oligomerization in aqueous solution to give uroporphyrinogen (4 isomers) in good yield. ALA, PBG, and uroporphyrinogen III are universal precursors to all known tetrapyrrole macrocycles. The enzymic formation of PBG entails carbon-carbon bond formation between the less stable enolate/enamine of one ALA molecule (3-position) and the carbonyl/imine (4-position) of the second ALA molecule; without enzymes, the first ALA reacts at the more stable enolate/enamine (5-position) and gives the pyrrole pseudo-PBG. pseudo-PBG cannot self-condense, yet has one open α-pyrrole position and is proposed to be a terminator of oligopyrromethane chain-growth from PBG. Here, 23 analogues of ALA have been subjected to density functional theoretical (DFT) calculations, but no motif has been identified that directs reaction at the 3-position. Deuteriation experiments suggested 5-(phosphonooxy)levulinic acid would react preferentially at the 3- versus 5-position, but a hybrid condensation with ALA gave no observable uroporphyrin. The results suggest efforts toward a biomimetic, enzyme-free route to tetrapyrroles from ALA should turn away from structure-directed reactions and focus on catalysts that orient the two aminoketones to form PBG in a kinetically controlled process, thereby avoiding formation of pseudo-PBG.

  18. Ambient noise near the sea-route

    Institute of Scientific and Technical Information of China (English)

    HE Li; LI ZhengLin; PENG ZhaoHui

    2009-01-01

    Ambient noise data measured in an experiment conducted in shallow water near a sea-route were analyzed. It was observed that, at low frequency, the horizontal correlation has an obvious difference from that predicted by the classical ambient noise model. The theoretical analyses show that this phenomenon is caused by wind noise together with the discrete shipping noise nearby. An ambient noise model was proposed to include the effects caused by both the noise sources. Data measured at different times verify that the proposed model can be used to forecast the ambient noise field in shal-low water near the sea-route.

  19. Ambient noise near the sea-route

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Ambient noise data measured in an experiment conducted in shallow water near a sea-route were analyzed. It was observed that, at low frequency, the horizontal correlation has an obvious difference from that predicted by the classical ambient noise model. The theoretical analyses show that this phenomenon is caused by wind noise together with the discrete shipping noise nearby. An ambient noise model was proposed to include the effects caused by both the noise sources. Data measured at different times verify that the proposed model can be used to forecast the ambient noise field in shallow water near the sea-route.

  20. An Improved Wireless Sensor Network Routing Algorithm

    Institute of Scientific and Technical Information of China (English)

    Shengmei Luo; Xue Li; Yiai Jin; Zhixin Sun

    2015-01-01

    High performance with low power consumption is an essential factor in wireless sensor networks (WSN). In order to address the issue on the lifetime and the consumption of nodes in WSNs, an improved ad hoc on⁃demand distance vector rout⁃ing (IAODV) algorithm is proposed based on AODV and LAR protocols. This algorithm is a modified on⁃demand routing al⁃gorithm that limits data forwarding in the searching domain, and then chooses the route on basis of hop count and power consumption. The simulation results show that the algorithm can effectively reduce power consumption as well as prolong the network lifetime.

  1. Plasma-assisted CuO/CeO2/TiO2-γ-Al2O3 catalysts for NO + CH4 reaction and NO temperature programmed desorption studies

    International Nuclear Information System (INIS)

    The removal of NO and CH4 has been studied with a hybrid system integrating plasma activation and four Cu-based catalysts. The best catalytic performance was observed for catalysts obtained from CuO/CeO2/TiO2/γ-Al2O3. The efficiency of NO removal decreased with the order: 12%CuO/10%CeO2/15%TiO2/γ-Al2O3 > 12%CuO/15%TiO2/γ-Al2O3 > 12%CuO/γ-Al2O3 > 12% CuO/TiO2. Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD) Temperature-programmed reduction (H2-TPR) and NO temperature-programmed desorption (NO-TPD) experiments were carried out to gain insight into the synergetic effects with the catalysts. The results revealed that copper species existed as bulk CuO crystalline for all the catalysts, H2-TPR suggested that the Cu2+ incorporated TiO2 or CeO2 lattice and crystalline CuO might be the most active component for NO removal, and NO-TPD studies indicated that 12%CuO/10%CeO2/15%TiO2/γ-Al2O3 catalyst had lower NO desorption temperature and larger peak area, which seemed to be responsible for the better catalytic activity over NO + CH4 reactions than other catalysts.

  2. Quantification of the Polyisoprenylated Benzophenones Garcinol and Isogarcinol Using Multiple Reaction Monitoring LC/Electrospray Ionization-MS/MS Analysis of Ultrasound-Assisted Extracts of Garcinia indica Fruits.

    Science.gov (United States)

    Bharate, Jaideep Bibishan; Vishwakarma, Ram Ashrey; Bharate, Sandip Bibishan; Kushwaha, Manoj; Gupta, Ajai Prakash

    2014-01-01

    This paper describes a method that includes an optimized extraction process and identification and quantification of two anticancer compounds (garcinol and isogarcinol) by LC/electrospray ionization (ESI)-MS/MS in the multiple reaction monitoring (MRM) mode. The study aimed to develop a fast, accurate, and sensitive method for the quantification of garcinol and isogarcinol in different extracts of Garcinia indica fruits. The compounds were detected using LC/ESI-MS/MS in the positive-ion mode and quantified in the MRM mode using a transition mass of m/z 603.3/411 taken as the quantifier and 603.3/343.2 as the qualifier for garcinol and isogarcinol. Five point calibration curves were linear in the range of 2 to 10 ng/mL for garcinol and 0.5 to 6 ng/mL for isogarcinol, with a correlation coefficient of ≥0.990 for both. LOQ for garcinol and isogarcinol was 0.06 and 0.05 ng/mL, respectively, while LOD was 0.021 and 0.017 ng/mL respectively. Our work demonstrated optimization of extraction procedure, fast and highly sensitive quantification (pg level LOQ), and validation of the developed method for the investigated compounds in fruit extracts of G. indica. PMID:25902981

  3. Sustainability Assessment of Chemical Processes: Evaluation of Three Synthesis Routes of DMC

    Directory of Open Access Journals (Sweden)

    Paula Saavalainen

    2015-01-01

    Full Text Available This paper suggested multicriteria based evaluation tool to assess the sustainability of three different reaction routes to dimethyl carbonate: direct synthesis from carbon dioxide and methanol, transesterification of methanol and propylene carbonate, and oxidative carbonylation of methanol. The first two routes are CO2-based and in a research and development phase, whereas the last one is a commercial process. The set of environmental, social, and economic indicators selected were renewability of feedstock, energy intensity, waste generation, CO2 balance, yield, feedstock price, process costs, health and safety issues of feedstock, process conditions, and innovation potential. The performance in these indicators was evaluated with the normalized scores from 0 to +1; 0 for detrimental and 1 for favorable impacts. The assessment showed that the transesterification route had the best potential toward sustainability, although there is still much development needed to improve yield. Further, the assessment gave clear understanding of the main benefits of each reaction route, as well as the major challenges to sustainability, which can further aid in orienting development efforts to key issues that need improvement. Finally, it was concluded that a multicriteria analysis such as the one presented in this paper was a viable method to be used in the process design stage.

  4. Concise Synthesis of Photocleavable Molecular Tag for Laser Desorption Ionization Mass Spectrometry via Fries Reaction

    OpenAIRE

    Gathirwa, Jeremiah W.; Maki, Toshihide

    2013-01-01

    A new synthetic route for the photocleavable molecular tag for laser desorption ionization mass spectrometry (LDI-MS) was achieved using Fries reaction of 2,6-dimethylphenyl ester as its key reaction. Zirconium chloride was found as uniquely efficient adjuvant to promote the reaction. The molecular tag was obtained in 5 steps without chromatographic purification.

  5. Hybrid chemical vapour and nanoceramic aerosol assisted deposition for multifunctional nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, Michael E.A.; Dunnill, Charles W.; Goodall, Josie; Darr, Jawwad A.; Binions, Russell, E-mail: uccarbi@ucl.ac.uk

    2011-07-01

    Hybrid atmospheric pressure chemical vapour and aerosol assisted deposition via the reaction of vanadium acetylacetonate and a suspension of preformed titanium dioxide or cerium dioxide nanoparticles, led to the production of vanadium dioxide nanocomposite thin films on glass substrates. The preformed nanoparticle oxides used for the aerosol were synthesised using a continuous hydrothermal flow synthesis route involving the rapid reaction of a metal salt solution with a flow of supercritical water in a flow reactor. Multifunctional nanocomposite thin films from the hybrid deposition process were characterised using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The functional properties of the films were evaluated using variable temperature optical measurements to assess thermochromic behaviour and methylene blue photodecolourisation experiments to assess photocatalytic activity. The tests show that the films are multifunctional in that they are thermochromic (having a large change in infra-red reflectivity upon exceeding the thermochromic transition temperature) and have significant photocatalytic activity under irradiation with 254 nm light.

  6. Nanocomposite Coatings Codeposited with Nanoparticles Using Aerosol-Assisted Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Xianghui Hou

    2013-01-01

    Full Text Available Incorporating nanoscale materials into suitable matrices is an effective route to produce nanocomposites with unique properties for practical applications. Due to the flexibility in precursor atomization and delivery, aerosol-assisted chemical vapour deposition (AACVD process is a promising way to synthesize desired nanocomposite coatings incorporating with preformed nanoscale materials. The presence of nanoscale materials in AACVD process would significantly influence deposition mechanism and thus affect microstructure and properties of the nanocomposites. In the present work, inorganic fullerene-like tungsten disulfide (IF-WS2 has been codeposited with Cr2O3 coatings using AACVD. In order to understand the codeposition process for the nanocomposite coatings, chemical reactions of the precursor and the deposition mechanism have been studied. The correlation between microstructure of the nanocomposite coatings and the codeposition mechanism in the AACVD process has been investigated. The heterogeneous reaction on the surface of IF-WS2 nanoparticles, before reaching the substrate surface, is the key feature of the codeposition in the AACVD process. The agglomeration of nanoparticles in the nanocomposite coatings is also discussed.

  7. Microwave-assisted wet digestion with H2O2 at high temperature and pressure using single reaction chamber for elemental determination in milk powder by ICP-OES and ICP-MS.

    Science.gov (United States)

    Muller, Edson I; Souza, Juliana P; Muller, Cristiano C; Muller, Aline L H; Mello, Paola A; Bizzi, Cezar A

    2016-08-15

    In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL(-1) of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation. PMID:27260458

  8. Plasma-assisted CuO/CeO{sub 2}/TiO{sub 2}-γ-Al{sub 2}O{sub 3} catalysts for NO + CH{sub 4} reaction and NO temperature programmed desorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huijuan, E-mail: muzilihuijuan@163.com [Faculty of Science, Southwest Forestry University, Kunming 650224 (China); Jiang, Xiaoyuan; Zheng, Xiaoming [Institute of Catalysis, Faculty of Science, Zhejiang University, Hangzhou, 310028 (China)

    2013-09-01

    The removal of NO and CH{sub 4} has been studied with a hybrid system integrating plasma activation and four Cu-based catalysts. The best catalytic performance was observed for catalysts obtained from CuO/CeO{sub 2}/TiO{sub 2}/γ-Al{sub 2}O{sub 3}. The efficiency of NO removal decreased with the order: 12%CuO/10%CeO{sub 2}/15%TiO{sub 2}/γ-Al{sub 2}O{sub 3} > 12%CuO/15%TiO{sub 2}/γ-Al{sub 2}O{sub 3} > 12%CuO/γ-Al{sub 2}O{sub 3} > 12% CuO/TiO{sub 2}. Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD) Temperature-programmed reduction (H{sub 2}-TPR) and NO temperature-programmed desorption (NO-TPD) experiments were carried out to gain insight into the synergetic effects with the catalysts. The results revealed that copper species existed as bulk CuO crystalline for all the catalysts, H{sub 2}-TPR suggested that the Cu{sup 2+} incorporated TiO{sub 2} or CeO{sub 2} lattice and crystalline CuO might be the most active component for NO removal, and NO-TPD studies indicated that 12%CuO/10%CeO{sub 2}/15%TiO{sub 2}/γ-Al{sub 2}O{sub 3} catalyst had lower NO desorption temperature and larger peak area, which seemed to be responsible for the better catalytic activity over NO + CH{sub 4} reactions than other catalysts.

  9. A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics.

    Science.gov (United States)

    Thiyagarajan, Shanmugam; Genuino, Homer C; van der Waal, Jan C; de Jong, Ed; Weckhuysen, Bert M; van Haveren, Jacco; Bruijnincx, Pieter C A; van Es, Daan S

    2016-01-22

    Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80% selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H-Y was found to perform the best and can be easily reused after calcination. PMID:26684008

  10. Microwave assisted synthesis and in silico screening of steroidal pyrazolines

    Institute of Scientific and Technical Information of China (English)

    Mahboob Alam; Shahab A.A. Nami; M. Parveen; Dong-Ung Lee; Soonheum Park

    2012-01-01

    The present manuscript describes solid-state synthesis of some reported steroidal pyrazolines by a novel eco-friendly route.The synthesized pyrazolines were compared with those obtained from conventional methods in terms of reaction time and overall yield.A substantial enhancement in reaction rate and yield was observed.The antimicrobial activity and the subsequent molecular docking studies of the steroidal pyrazolines have also been carried out.

  11. Assisted Living Community Profile

    Science.gov (United States)

    ... for the Seniors Housing & Care Industry, reflects NCAL's philosophy of assisted living. 2 Data also from the ... Assisted Living Studies Clinical Practice Guidelines Health Information Technology In-Service Training Tools Periodicals State Regulatory Review ...

  12. Assisted Vaginal Delivery

    Science.gov (United States)

    ... having a repeat assisted vaginal delivery in a future pregnancy? If you have had one assisted vaginal ... Education Green Journal Practice Management Coding Health Info Technology Professional Liability Managing Your Practice Patient Safety & Quality ...

  13. ForeignAssistance.gov

    Data.gov (United States)

    US Agency for International Development — ForeignAssistance.gov provides a view of U.S. Government foreign assistance funds across agencies and enables users to explore, analyze, and review aid investments...

  14. Assisted Reproductive Technology (ART)

    Science.gov (United States)

    ... Information Clinical Trials Resources and Publications Assisted Reproductive Technology (ART) Skip sharing on social media links Share ... American Society for Reproductive Medicine. (2012). Assisted reproductive technologies: A guide for patients . Retrieved June 11, 2012, ...

  15. VIDEO ASSISTED THYROIDECTOMY

    OpenAIRE

    C. Bradea

    2009-01-01

    Video assisted techniques were documented by M.Gagner (1996 – video assisted parathyroidectomy), Henry (1999), Shimizu (1999), Ohgami (2000), Miccoli (2000 – video assisted parathyroidectomy and thyroidectomy). The advantage of this kind of surgery: aesthetics i.e. trying to make only small scars on the neck. Our first case of video assisted thyroidectomy was a female 50 years of age, with multinodular goiter, nodules of 2-3 cm in each lobe, admitted in our clinic in December 2008. History of...

  16. Mobile IPv6 Route Optimization Protocol

    Directory of Open Access Journals (Sweden)

    Aumdevi K. Barbudhe

    2013-07-01

    Full Text Available Mobile IPv6 (MIPv6 allows a Mobile Node to talk directly to its peers while retaining the ability to move around and change the currently used IP address. This mode of operation is called Route Optimization (RO, as it allows the packets to traverse a shorter route than the default one through the Home Agent. In Route Optimization, the peer node learns a binding between the Mobile Node’s permanent Home Address and its current temporary Care-ofAddress. Once such a binding is in place, the peer node will send all packets whose destination is the Home Address to the Care-ofAddress. This is potentially dangerous, since a malicious host might be able to establish false bindings, thereby preventing some packets from reaching their intended destination, diverting some traffic to the attacker, or flooding third parties with unwanted traffic. In this paper we discuss the design rationale behind the MIPv6 Route Optimization Security Design

  17. Traffic disruption route Einstein near building 170

    CERN Multimedia

    A Lopez - TS/CE

    2005-01-01

    The TS/CE Group informs you that, for the duration of the work at Building 170, there may be some disruption to traffic on route Einstein in the vicinity of Building 170. The work is due to take place from the 14th to 18th February. For more information, please contact 165029. A. Lopez TS/CE

  18. Wales energy route map consultation : SDC response

    OpenAIRE

    Sustainable Development Commission Wales

    2005-01-01

    Sustainable Development Commission submission to the Welsh Assembly Government’s consultation on 'Energy Wales : route map to a clean, low-carbon and more competitive energy future for Wales'. Topics covered include Raising awareness, energy efficiency, renewable energy, coal/carbon capture storage, energy infrastructure and reducing carbon dioxide emissions. Publisher PDF

  19. Automated Flight Routing Using Stochastic Dynamic Programming

    Science.gov (United States)

    Ng, Hok K.; Morando, Alex; Grabbe, Shon

    2010-01-01

    Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.

  20. Mingling Multipath Routing With Quality Of Service

    Directory of Open Access Journals (Sweden)

    Dr. Shuchita Upadhyaya

    2011-09-01

    Full Text Available The QoS issue in the Internet have become essential for the successful transmission of multimedia applications . The basic problem of QoS routing is to find a path satisfying multiple constraints. It is concerned with identifying the path that will consider multiple parameters like bandwidth, delay, cost, hopcount etc. instead of one .To provide user- or application-level Quality of Service (QoS guarantee Multipath routing strategy can be used for the transmission of QoS sensitive traffic over the network. Multipath routing means using multiple paths instead of using single path to forward the traffic.If multiple paths are being used for the transmission of the traffic then the traffic will be redirected to the back up path if active path fails. In this way robustness can be achieved. On the other hand load balancing for communication network to avoid network congestion optimize network throughput also requires multi paths to distribute flows . Robustness load balancing are aspects of QoS routing . So multipath can be proved very valuable for Quality of service. This paper investigates the approaches of mingling Multipath Quality of service. The approaches considered are based on Dijkstra algorithm, Bellman ford algorithm, Resource reservation MPLS.

  1. Network Routing Optimization Using Swarm Intelligence

    OpenAIRE

    Galil, Mohamed A. El

    2012-01-01

    The aim of this paper is to highlight and explore a traditional problem, which is the minimum spanning tree, and finding the shortest-path in network routing, by using Swarm Intelligence. This work to be considered as an investigation topic with combination between operations research, discrete mathematics, and evolutionary computing aiming to solve one of networking problems.

  2. Routing Algorithms for Wireless Sensor Networks

    OpenAIRE

    Raicu, Ioan

    2004-01-01

    Our contribution in this paper is e3D, a diffusion based routing protocol that prolongs the system lifetime, evenly distributes the power dissipation throughout the network, and incurs minimal overhead for synchronizing communication. We compare e3D with other algorithms in terms of system lifetime, power dissipation distribution, cost of synchronization, and simplicity of the algorithm.

  3. ROUTE PLAN DESIGNER FOR TRACTOR GUIDANCE SYSTEMS

    DEFF Research Database (Denmark)

    Sveistrup, Daniel; Jørgensen, Rasmus Nyholm; Green, Ole;

    2010-01-01

    Earlier works have shown field trial designs to be very labor extensive, even when combining autoguidancesystems with conventional machinery.Designing routes for semi-automated systems in a controlled manner is both resource demandingand complicated. Different types of auto-guidance systems vary ...

  4. Real Time Route for Dynamic Road Congestions

    Directory of Open Access Journals (Sweden)

    A. M. Riad

    2012-05-01

    Full Text Available Minimizing service delivery and travel time during rush hours downtown is strategic target for several organizations, especially the emergency organizations. This paper presents an On-line and Real-time Dynamic Route System (ORDRS which benefits from the advantages and integration between information system and communications technology. It utilizes Global Positioning System (GPS, Geographical Information Systems (GIS, and Global System for Mobile communications (GSM; for producing the real time routes for vehicles. GPS-Tracker is the main input device for ORDRS. It is fixated in a vehicle, sends vehicle's movement data (Geo-info to the control center wirelessly through either Short Message Service (SMS or General Packet Radio Service (GPRS. Geo-info includes time, date, longitude, latitude, speed, and etc., these data is classified over time during weekdays into interval time slices, each slice is 30 minutes. Speeds are treated by GIS tools to determine historical and real time speeds for each street segment in the road network which is being used for calculating time impedance (cost matrix for each street segment dynamically. ORDRS uses a cost matrix of the current time slice for determining the best route to each vehicle in duty attached. Several algorithms was used to calculate the shortest route, a comparison between Dijekstra and Yen algorithms was studied.

  5. Locating Depots for Capacitated Vehicle Routing

    CERN Document Server

    Goertz, Inge Li

    2011-01-01

    We study a location-routing problem in the context of capacitated vehicle routing. The input is a set of demand locations in a metric space and a fleet of k vehicles each of capacity Q. The objective is to locate k depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for this problem. To achieve this result, we reduce to the k-median-forest problem, which generalizes both k-median and minimum spanning tree, and which might be of independent interest. We give a (3+c)-approximation algorithm for k-median-forest, which leads to a (12+c)-approximation algorithm for the above location-routing problem, for any constant c>0. The algorithm for k-median-forest is just t-swap local search, and we prove that it has locality gap 3+2/t; this generalizes the corresponding result known for k-median. Finally we consider the "non-uniform" k-median-forest problem which has different cost ...

  6. Low Mobility Based Geographic Routing Strategy

    Directory of Open Access Journals (Sweden)

    Prashanth Kolandaiswami Arjunan

    2014-02-01

    Full Text Available In geographic routing, nodes need to maintain up-to-date positions of their immediate neighbours for making effective forwarding decisions. Periodic broadcasting of beacon packets regardless of the node mobility and traffic patterns are proved to increase the update cost and decreases the routing performance. If only a small percentage of the nodes are involved in forwarding packets, it is unnecessary for nodes which are located far away from the forwarding path to employ periodic beaconing because these updates are not useful for forwarding the current traffic. Hence Adaptive Position Update (APU Scheme was introduced, (i nodes whose movements are harder to predict update their positions more frequently (and vice versa, and (ii nodes closer to forwarding paths update their positions more frequently (and vice versa. Further we contend that if forwarding nodes have high mobility there is an increased risk of frequent link failures. Thereby we propose a low mobility based forwarding node selection strategy to improve the routing performance and energy efficiency of the nodes in the system. Extensive simulations demonstrated that our routing strategy has two interesting features: 1 Less number of link failures with improved packet delivery ratio. 2 Less energy consumption when compared to APU alone and periodic broadcasting schemes.

  7. Small World Model-Based Polylogarithmic Routing Using Mobile Nodes

    Institute of Scientific and Technical Information of China (English)

    Jie Wu; Shu-Hui Yang

    2008-01-01

    The use of mobile nodes to improve network system performance has drawn considerable attention recently.The movement-assisted model considers mobility as a desirable feature, where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes. The application of such a model has been used in several emerging networks, including mobile ad hoc networks (MANETs), wireless sensor networks (WSNs), and delay tolerant networks (DTNs). It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing, prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors, and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network. Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures,including delay, average number of relays, and moving distance. In this paper, we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals, including delay, the number of relays, and moving distance. The model is based on the small-world model where each static node has "short" link connections to its nearest neighbors and "long" link connections to other nodes following a certain probability distribution. Short links are regular wireless connections whereas long links are implemented using mobile nodes. Various issues are considered, including trade-offs between delay and average number of relays, selection of the number of mobilenodes, and selection of the number of long links. The effectiveness of the proposed model is evaluated analytically as well as through simulation.

  8. Polyoxometalate based soft chemical route for preparation of Pt nanorods and self-assemblies

    Indian Academy of Sciences (India)

    S Shanmugam; B Viswanathan; T K Varadarajan

    2005-10-01

    A soft chemical route is described for the preparation of platinum nanorods and self-assemblies over photochemically reduced polyoxometalate (silicotungstate) containing composite films. Transmission electron microscopy shows that the diameters of the platinum nanorods are around 55–60 nm. The formation of platinum nanorods on solid–liquid interface reactions was explained on the basis of single site growth mechanism and diffusion limitation aggregation process.

  9. A facile route to old and new cyclophanes via self-assembly and capture

    OpenAIRE

    Collins, Mary S.; Carnes, Matthew E.; Nell, Bryan P.; Zakharov, Lev N.; Johnson, Darren W.

    2016-01-01

    Cyclophanes are a venerable class of macrocyclic and/or cage compounds that often feature high strain, unusual conformations and quite surprising properties, many of which are legendary in physical organic chemistry. However, the discovery of new, diverse cyclophanes and derivatives has been hindered by syntheses that are traditionally low-yielding, requiring long reaction times, laborious purification steps and often extreme conditions. Herein, we demonstrate a new self-assembly route to a v...

  10. Shape and size controlled synthesis of uniform iron oxide nanocrystals through new non-hydrolytic routes.

    Science.gov (United States)

    Li, Wenlu; Lee, Seung Soo; Wu, Jiewei; Hinton, Carl H; Fortner, John D

    2016-08-12

    New, non-hydrolytic routes to synthesize highly crystalline iron oxide nanocrystals (8-40 nm, magnetite) are described in this report whereby particle size and morphology were precisely controlled through reactant (precursor, e.g. (FeO(OH)) ratios, co-surfactant and organic additive, and/or reaction time. Particle size, with high monodispersivity (materials synthesized/purified in organic solvents are broadly water dispersible through a variety of phase (aqueous) transfer method(s). PMID:27354334

  11. Preparation of Renewable Fuel from Saponificated China Tallow Oil by Fast Pyrolysis Reaction Assisted with Microwave%乌桕油皂微波催化快速裂解制备可再生燃油研究

    Institute of Scientific and Technical Information of China (English)

    王允圃; 程方园; 刘玉环; 阮榕生; 刘英语; 马雯; 杨倩; 黄伊宁

    2015-01-01

    Preparation of renewable fuel was studied with saponificated China tallow seed oil and stillingia oil as raw materials using microwave pyrolysis. The effects of reaction power and temperature on the yield of pyrolysis products were investigated. The optimum conditions were obtained as pyrolysis power 700 W, pyrolysis temperature 450 ℃. The corresponding liquid yields were 75. 26% and 77. 01% for microwave pyrolysis oil from saponificated China tallow seed oil and stillingia oil, respectively. The GC-MS analysis indicated that the main components of the product were C8-C18 alkanes, alkenes, ring-containing alkanes and aromatic hydrocarbon. Pyrolysis oil properties were also determined. The results indicated that the pyrolysis oil from saponificated China tallow seed oil had higher heat value, lower density and viscosity with the comparation of pyrolysis oil from saponificated China tallow stillingia oil, which was similar to 0# diesel. Freezing point and cold filter plugging point of the pyrolytic products have good low temperature fluidity, which are better than those of the biodiesel.%采用微波催化快速裂解技术,以乌桕木油皂和乌桕梓油皂为原料,利用其强极性羧基端吸收微波迅速的特点,研究了其制备可再生燃油的技术。考察了裂解功率、裂解温度对裂解产物得率的影响。结果表明:裂解功率700 W,裂解温度450℃,乌桕木油皂和乌桕梓油皂微波裂解液体燃料的得率分别为75.26%和77.01%, GC-MS分析表明,产物的主要成分为C8~C18的正构烷烃、烯烃、环烷烃以及芳香烃等烃类化合物。产物的部分燃料油性能测定结果表明,乌桕木油皂裂解燃油比乌桕梓油皂裂解燃油热值略高,密度和运动黏度略低,基本符合0#柴油的标准,冷凝点和冷滤点均优于生物柴油,低温流动性好。

  12. Nuclear reactions

    International Nuclear Information System (INIS)

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

  13. A comparison of the intradermal and subcutaneous routes of influenza vaccination with A/New Jersey/76 (swine flu) and A/Victoria/75: report of a study and review of the literature.

    Science.gov (United States)

    Halperin, W; Weiss, W I; Altman, R; Diamond, M A; Black, K J; Iaci, A W; Black, H C; Goldfield, M

    1979-01-01

    A trail of influenza vaccination, with use of bivalent split virus vaccine (A/New Jersey/76 and A/Victoria/75), was conducted to compare the immunogenicity and reactions when vaccine was given by the subcutaneous and intradermal routes. Volunteers 18 to 24 years old were randomized into equal groups, one group receiving 0.1 ml of vaccine intradermally and the other receiving 0.5 ml subcutaneously. For the A/Victoria vaccine, the immunogenicity of the intradermal route seemed superior; for A/New Jersey vaccine, the routes were equivalent. Adverse reactions were minimal and equivalent for both groups. In times of vaccine shortage, the intradermal route is considered to stretch vaccine supplies. Field trials of new influenza vaccines should include evaluation of the immunogenicity of and adverse reactions caused by the same vaccine given by different routes in varied dosages. PMID:507256

  14. An Analysis of Routing Disruption Attack on Dynamic Source Routing Protocol

    CERN Document Server

    Sen, Jaydip

    2011-01-01

    Dynamic Source Routing (DSR) is a well known source routing protocol for ad hoc networks. The algorithm depends on the cooperative participation of the nodes that enables route discovery from a source node to a destination node. However, if a group of nodes do not cooperate, the performance of the DSR protocol may be severely degraded. This paper presents a probabilistic attack model on the DSR protocol and analyses its effect on the routing performance. Simulations results of the model show that the effect of the attack is catastrophic only if a large number of nodes are compromised and there is no detection mechanism. As an interesting observation, the analysis also shows that the attack model can also be used to improve the performance of the DSR protocol.

  15. PNW River Reach Files -- 1:100k LLID Routed Streams (routes)

    Data.gov (United States)

    Pacific States Marine Fisheries Commission — This feature class includes the ROUTE features from the 2001 version of the PNW River Reach files Arc/INFO coverage. Separate, companion feature classes are also...

  16. Magnetic properties of lanthanum orthoferrite fine powders prepared by different chemical routes

    Indian Academy of Sciences (India)

    Benedict Ita; P Murugavel; V Ponnambalam; A R Raju

    2003-10-01

    Fine powders of lanthanum iron oxide, LaFeO3, have been prepared by solid state reaction as well as sol-gel synthesis and nebulized spray pyrolysis. Structures, morphologies and magnetic susceptibility measurements of these powders have been examined. The powders prepared by all the three low-temperature routes contain nearly spherical particles with an average diameter of 40 nm. These samples show a lower Neel temperature than the powder prepared by solid state reaction besides showing much lower magnetic susceptibility at low temperatures.

  17. Microscopy investigation of Ag-TCNQ micro/nanostructures synthesized via two solution routes.

    Science.gov (United States)

    Cao, Guanying; Fang, Fang; Ye, Chunnuan; Xing, Xiaoyan; Xu, Huahua; Sun, Dalin; Chen, Guorong

    2005-01-01

    The micro/nanostructures of metal-organic complex Ag-TCNQ were successfully synthesized by the reaction between Ag film and TCNQ dissolved in acetonitrile via two solution routes, i.e. immerging and dipping reaction. X-ray diffraction confirmed that the obtained Ag-TCNQ micro/nanostructures were crystalline. The morphology of the as-grown structures varied from straight nanowires and microtubes to complex fractals and dendrites. The growth mechanism of the mainly dendrites may be considered within the framework of DLA model. PMID:15725599

  18. RSRP: A Robust Secure Routing Protocol in MANET

    Directory of Open Access Journals (Sweden)

    Sinha Ditipriya

    2014-05-01

    Full Text Available In this paper, we propose a novel algorithm RSRP to build a robust secure routing protocol in mobile ad-hoc networks (MANETs. This algorithm is based on some basic schemes such as RSA_CRT for encryption and decryption of messages; CRT for safety key generation, Shamir’s secret sharing principle for generation of secure routes. Those routes which are free from any malicious node and which belong to the set of disjoint routes between a source-destination pair are considered as probable routes. Shamir’s secret sharing principle is applied on those probable routes to obtain secure routes. Finally, most trustworthy and stable route is selected among those secure routes. Selection of the final route depends on some criteria of the nodes present in a route e.g.: battery power, mobility and trust value. In addition, complexity of key generation is reduced to a large extent by using RSA-CRT instead of RSA. In turn, the routing becomes less expensive and most secure and robust one. Performance of this routing protocol is then compared with non-secure routing protocols (AODV and DSR, secure routing scheme using secret sharing, security routing protocol using ZRP and SEAD depending on basic characteristics of these protocols. All such comparisons show that RSRP shows better performance in terms of computational cost, end-to-end delay and packet dropping in presence of malicious nodes in the MANET, keeping the overhead in terms of control packets same as other secure routing protocols.

  19. Congestion control and routing over satellite networks

    Science.gov (United States)

    Cao, Jinhua

    Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE

  20. Chain-Chain Based Routing Protocol

    Directory of Open Access Journals (Sweden)

    Samia A Ali

    2011-05-01

    Full Text Available Wireless sensor network (WSN is an emerging technology for monitoring physical world. WSNs consist of large numbers of sensor nodes operated by battery mostly in harsh environment. Thus energy conservation is a primary issue for organization of these sensor nodes. Another crucial issue is the data delivery time by sensor nodes to the sink node, especially in Military, medical fields, and security monitoring systems where minimum delay is desirable. Number of protocols has been proposed in the literature for routing. One of such protocols is the cluster based routing protocol LEACH (low energy adaptive clustering hierarchy. LEACH protocol organizes WSN into a set of clusters and a periodic voting for cluster head is performed in order to be evenly distributed among all the sensors of the WSN. This periodical cluster head voting in LEACH, however, consumes an amount of non-negligible energy and other resources. For energy conservation, PEGASIS (power efficient gathering in sensor information systems a near optimal chain-based protocol has been proposed, however, it is faced with the challenge of long delay for the transmitted data. Another routing protocol called CCM (Chain-Cluster based Mixed routing, which is mainly a hybrid of LEACH and PEGASIS is proposed, the consumed energy increases as network size increases. In this paper, we propose an efficient routing protocol called CCBRP (Chain-Chain based routing protocol, it achieves both minimum energy consumption and minimum delay. The CCBRP protocol mainly divides a WSN into a number of chains (Greedy algorithm is used to form each chain as in PEGSIS protocol and runs in two phases. In the first phase, sensor nodes in each chain transmit data to their chain leader nodes in parallel. In the second phase, all chain leader nodes form a chain (also, using Greedy algorithm and choose randomly a leader node then all chain leader nodes send their data to this chosen leader node. This chosen leader node