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Sample records for micrometric fibers synthesized

  1. Functional Application of Noble Metal Nanoparticles In Situ Synthesized on Ramie Fibers

    Science.gov (United States)

    Tang, Bin; Yao, Ya; Li, Jingliang; Qin, Si; Zhu, Haijin; Kaur, Jasjeet; Chen, Wu; Sun, Lu; Wang, Xungai

    2015-09-01

    Different functions were imparted to ramie fibers through treatment with noble metal nanoparticles including silver and gold nanoparticles. The in situ synthesis of silver and gold nanoparticles was achieved by heating in the presence of ramie fibers in the corresponding solutions of precursors. The unique optical property of synthesized noble metal nanoparticles, i.e., localized surface plasmon resonance, endowed ramie fibers with bright colors. Color strength (K/S) of fibers increased with heating temperature. Silver nanoparticles were obtained in alkaline solution, while acidic condition was conducive to gold nanoparticles. The optical properties of treated ramie fibers were investigated using UV-vis absorption spectroscopy. Scanning electron microscopy (SEM) was employed to observe the morphologies of silver and gold nanoparticles in situ synthesized on fibers. The ramie fibers treated with noble metal nanoparticles showed remarkable catalytic activity for reduction of 4-nitrophenol (4-NP) by sodium borohydride. Moreover, the silver nanoparticle treatment showed significant antibacterial property on ramie fibers.

  2. Micrometre Scale Performances of Industrial Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Diala Dandash

    2012-10-01

    Full Text Available Robot precision is usually characterized by repeatability and accuracy. In this paper, we show that these indices are not sufficient to describe robot behaviour at the micrometre scale. New, precision performances are discussed and the experimental procedure to estimate these indices is described. The main results of the experimental work performed on Samsung Faraman and Epson Scara robots are displayed. Reversibility, hysteresis and spatial resolution have to be taken into account when the robot has to be controlled precisely at the micrometre scale. A granular control design including harmonization poses is proposed as a conclusion.

  3. Micrometre Scale Performances of Industrial Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Diala Dandash

    2012-10-01

    Full Text Available Robot precision is usually characterized by repeatability and accuracy. In this paper, we show that these indices are not sufficient to describe robot behaviour at the micrometre scale. New, precision performances are discussed and the experimental procedure to estimate these indices is described. The main results of the experimental work performed on Samsung Faraman and Epson Scara robots are displayed. Reversibility, hysteresis and spatial resolution have to be taken into account when the robot has to be controlled precisely at the micrometre scale. A granular control design including harmonization poses is proposed as a conclusion.

  4. Micrometric alignment metrology means, developments and applications

    CERN Document Server

    Mainaud-Durand, H

    2004-01-01

    In order to meet the ever-increasing drastic alignment tolerances concerning the future particle accelerators, a new generation of sensors has been developed. Whether they are based on ultrasonic, optical or capacitive technology, these sensors, of micrometric resolution, allow continuous measurements in an often hostile environment (strong radiations, strong electro-magnetic fields) and thereby revolutionize alignment possibilities. After a brief presentation of the different sensors tested, used and indeed developed by our group, we present the past, present and future applications linked to the particle accelerators - in the short term concerning micrometric alignment of the low-beta quadrupoles of the LHC, and in the long term concerning the prealignment of the CLIC - or linked to other applications.

  5. High speed sub-micrometric microscopy using optical polymer microlens

    Institute of Scientific and Technical Information of China (English)

    X.H.Zeng; J.Plain; S.Jradi; P.Renaud Goud; R.Deturche; P.Royer; R.Bachelot

    2009-01-01

    We report the high speed scanning submicronic microscopy (SSM) using a low cost polymer microlens integrated at the extremity of an optical fiber.These microlenses are fabricated by a free-radical photopolymerization method.Using a polymer microlens with a radius of curvature of 250 nm,a sub-micrometric gold pattern is imaged experimentally by SSM.Different distances between the tip and the sample are used with a high scanning speed of 200 cm/s.In particular,metallic absorption contrasts are described with an optical spatial resolution of 250 nm at the wavelength of 532 nm.Moreover,finite-difference time-domain (FDTD) simulations concerning the focal lengths of microlenses with different geometries and heights support the experimental data.

  6. Multi-wall carbon nanotubes supported on carbon fiber paper synthesized by simple chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ya-hao [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Zhengzhou Research Institute of Chalco, Zhengzhou 450041 (China); Gao, Hong-quan [Zhengzhou Research Institute of Chalco, Zhengzhou 450041 (China); Yang, Jian-hong, E-mail: zyy_yjh@rilm.com.cn [Zhengzhou Research Institute of Chalco, Zhengzhou 450041 (China); Gao, Wen-liang; Xiang, Jia [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Li, Qing-yu, E-mail: 13975808173@126.com [School of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin, Guangxi 541004 (China)

    2014-09-15

    Highlights: • We deposited multi-wall carbon nanotubes on carbon fiber paper with a simple CVD. • We investigated the inherent mechanism of Ni particle's self-dispersion. • The MWCNTs/CFP composite possesses wonderful electrical conductivity. - Abstract: Aiming at developing a novel carbon/carbon composite as an electrode in the electrochemical capacitor applications, multi-wall carbon nanotubes (MWCNTs)/carbon fiber paper (CFP) composite has been synthesized using a simple chemical vapor deposition, in which different metal catalysts such as Fe, Ni and Cu are used. However, randomly oriented MWCNTs were only obtained on Ni particles. The mechanism for this unique phenomenon is investigated in this article. The physical and electrochemical properties of as-prepared MWCNTs/CFP composite are characterized and the results show that the as-prepared composite is a promising substrate for electrochemical capacitor applications.

  7. Laser spectroscopy of sub-micrometre- and micrometre-thick caesium-vapour layers

    Energy Technology Data Exchange (ETDEWEB)

    Cartaleva, S; Krasteva, A; Slavov, D; Todorov, P; Vaseva, K [Institute of Electronics, Bulgarian Academy of Sciences, boul. Tzarigradsko shosse 72, 1784 Sofia (Bulgaria); Moi, L [CNISM and Physics Department, University of Siena, via Roma 56, 53100 Siena - Italy (Italy); Sargsyan, A; Sarkisyan, D [Institute for Physical Research, National Academy of Sciences of Armenia, Ashtarak-0203 (Armenia)

    2013-09-30

    We present high resolution laser spectroscopy of Cs vapours confined in a unique optical cell of sub-micrometric and micrometric thickness, where a strong spatial anisotropy is present for the time of interaction between the atoms and laser radiation. Similarly to the spectra of selective specular reflection, the Doppler-free spectra of absorption and fluorescence are observed, not revealing cross-over resonances that will be useful for frequency stabilisation, provided the cell is cheap and compact. A new resonance in the fluorescence of closed transition is studied, demonstrating its high sensitivity to elastic atom – atom and atom – dielectric surface collisions. The theoretical modelling performed is in agreement with the experimental observations. (laser spectroscopy)

  8. Nonlinear pulse compression of picosecond parabolic-like pulses synthesized with a long period fiber grating filter.

    Science.gov (United States)

    Krcmarík, David; Slavík, Radan; Park, Yongwoo; Azaña, José

    2009-04-27

    tract: We demonstrate high quality pulse compression at high repetition rates by use of spectral broadening of short parabolic-like pulses in a normally-dispersive highly nonlinear fiber (HNLF) followed by linear dispersion compensation with a conventional SMF-28 fiber. The key contribution of this work is on the use of a simple and efficient long-period fiber grating (LPFG) filter for synthesizing the desired parabolic-like pulses from sech(2)-like input optical pulses; this all-fiber low-loss filter enables reducing significantly the required input pulse power as compared with the use of previous all-fiber pulse re-shaping solutions (e.g. fiber Bragg gratings). A detailed numerical analysis has been performed in order to optimize the system's performance, including investigation of the optimal initial pulse shape to be launched into the HNLF fiber. We found that the pulse shape launched into the HNLF is critically important for suppressing the undesired wave breaking in the nonlinear spectral broadening process. The optimal shape is found to be independent on the parameters of normally dispersive HNLFs. In our experiments, 1.5-ps pulses emitted by a 10-GHz mode-locked laser are first reshaped into 3.2-ps parabolic-like pulses using our LPFG-based pulse reshaper. Flat spectrum broadening of the amplified initial parabolic-like pulses has been generated using propagation through a commercially-available HNLF. Pulses of 260 fs duration with satellite peak and pedestal suppression greater than 17 dB have been obtained after the linear dispersion compensation fiber. The generated pulses exhibit a 20-nm wide supercontinuum energy spectrum that has almost a square-like spectral profile with >85% of the pulse energy contained in its FWHM spectral bandwidth.

  9. Effect of Amino Acids on Morphology of Hydrothermally Synthesized Hydroxyapatite Fibers

    Directory of Open Access Journals (Sweden)

    QI Mei-li

    2017-05-01

    Full Text Available Based on the basic principle of biomineralization, hydroxyapatite fiber (HAF with high crystallinity was fabricated via a hydrothermal route with Ca(NO32·4H2O and (NH42HPO4 as the resources, respectively. Effects of the addition of acidic amino acid L-glutamic acid (Glu, neutral amino acid L-phenylalanine (Phe and basic amino acid L-lysine (Lys on the phase composition and morphology of the obtained products were laid special emphasis on. The results show that the products obtained by using the three amino acids are all hydroxyapatite (HA phase with minor CaCO3 in some samples. Meanwhile, all of the amino acids inhibit the growth of the fibers. Spherical morphology exists when Glu is added, the homogeneity of the fibers deteriorates with the addition of Lys. However, rod-like fibers with good uniformity can be obtained with the addition of Phe.

  10. A Facile Route to Synthesize Nanographene Reinforced PBO Composites Fiber via in Situ Polymerization

    Directory of Open Access Journals (Sweden)

    Mingqiang Wang

    2016-07-01

    Full Text Available The polymer matrix with introduced carbon-based nanofiber displays fascinating properties. They have inspired extensive research on the synthesis of polymer composites, which have been applied in catalysis, electronics, and energy storage. In this report, we reported a facile and efficient method to prepare poly(p-phenylene benzobisoxazole (PBO/nanographene (PNG composites fibers via in-situ polymerization, accompanied by the reduction from (nanographene oxide NGO to (nanographene NG. By tuning the ratio of feeding PBO monomer to NGO, various composites fibers with 0.1–1 wt % contents of NG were obtained. The efficient PBO chains grafting made NG uniformly disperse in the PBO matrix, and it also increased the uniformity of the packing orientation of PBO chains. Consequently, the tensile strength, tensile modulus, and thermal stability of the obtained PNG composites fibers had been improved significantly. In addition, the composites fibers with 0.5 wt % NG exhibited a 25% increment in tensile strength, and a 41% enhancement in tensile modulus compared with neat PBO fibers. It reveals an excellent reinforcement to PBO composites fibers with NG.

  11. The comparison of photocatalytic activity of synthesized TiO 2 and ZrO 2 nanosize onto wool fibers

    Science.gov (United States)

    Moafi, Hadi Fallah; Shojaie, Abdollah Fallah; Zanjanchi, Mohammad Ali

    2010-04-01

    TiO 2 and ZrO 2 nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO 2-coated and ZrO 2-coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO 2-coated and 20-40 nm in size for ZrO 2-coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO 2 modified sample with respect to that of ZrO 2 for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.

  12. Direct atomic-level observation and chemical analysis of ZnSe synthesized by in situ high-throughput reactive fiber drawing.

    Science.gov (United States)

    Hou, Chong; Jia, Xiaoting; Wei, Lei; Stolyarov, Alexander M; Shapira, Ofer; Joannopoulos, John D; Fink, Yoel

    2013-03-13

    We demonstrate a high-throughput method for synthesizing zinc selenide (ZnSe) in situ during fiber drawing. Central to this method is a thermally activated chemical reaction occurring across multiple interfaces between alternately layered elemental zinc- (Zn-) and selenium- (Se-) rich films embedded in a preform and drawn into meters of fiber at a temperature well below the melting temperature of either Zn or ZnSe. By depositing 50 nm thick layers of Zn interleaved between 1 μm thick Se layers, a controlled breakup of the Zn sheet is achieved, thereby enabling a complete and controlled chemical reaction. The thermodynamics and kinetics of this synthesis process are studied using thermogravimetric analysis and differential scanning calorimetry, and the in-fiber compound is analyzed by a multiplicity of materials characterization tools, including transmission electron microscopy, Raman microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction, all resulting in unambiguous identification of ZnSe as the compound produced from the reactive fiber draw. Furthermore, we characterize the in-fiber ZnSe/Se97S3 heterojunction to demonstrate the prospect of ZnSe-based fiber optoelectronic devices. The ability to synthesize new compounds during fiber drawing at nanometer scale precision and to characterize them at the atomic-level extends the architecture and materials selection compatible with multimaterial fiber drawing, thus paving the way toward more complex and sophisticated functionality.

  13. Antibacterial properties of biomedical surfaces containing micrometric silver islands

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Tanoira, R; Perez-Jorge, C; Endrino, J L; Gomez-Barrena, E; Horwat, D; Pierson, J F; Esteban, J, E-mail: rptanoira@fjd.es

    2010-11-01

    A set of Cu-Mn-O and Ag-Cu-Mn-O films were sputter-deposited onto polished Ti-6Al-4V coupons and the microbiological adherence of Staphylococcus sp. was studied in these biomedical surfaces modified using advanced ternary and quaternary oxides that incorporated micrometric silver islands. The as-deposited ternary and quaternary compounds were amorphous. Upon air annealing the Ag-Cu-Mn-O films, silver-oxygen bonds in the compound destabilize, resulting in the segregation of metallic silver in the form of micrometric layered silver islands with high specific area dispersed at the surface of the remaining oxide. Silver is well known to have a natural biocidal character and its presence in the surface forming large micrometric escalonated islands is, in principle, predicted to enhance the antimicrobial properties of biomedical surfaces. Microbial adhesion tests were performed in triplicates using collection strains of Staphylococcus aureus and Staphylococcus epidermidis. Preliminary results indicate that both strains showed decreased adherence to modified materials, S. epidermidis showed higher adherence these materials than S. aureus, however, there was no statistically significant differences between Cu-Mn-O and Ag-Cu-Mn-O containing silver islands.

  14. Ultrafine Au and Ag Nanoparticles Synthesized from Self-Assembled Peptide Fibers and Their Excellent Catalytic Activity.

    Science.gov (United States)

    Xu, Wenlong; Hong, Yue; Hu, Yuanyuan; Hao, Jingcheng; Song, Aixin

    2016-07-18

    The self-assembly of an amphiphilic peptide molecule to form nanofibers facilitated by Ag(+) ions was investigated. Ultrafine AgNPs (NPs=nanoparticles) with an average size of 1.67 nm were synthesized in situ along the fibers due to the weak reducibility of the -SH group on the peptide molecule. By adding NaBH4 to the peptide solution, ultrafine AgNPs and AuNPs were synthesized with an average size of 1.35 and 1.18 nm, respectively. The AuNPs, AgNPs, and AgNPs/nanofibers all exhibited excellent catalytic activity toward the reduction of 4-nitrophenol, with turnover frequency (TOF) values of 720, 188, and 96 h(-1) , respectively. Three dyes were selected for catalytic degradation by the prepared nanoparticles and the nanoparticles showed selective catalysis activity toward the different dyes. It was a surprising discovery that the ultrafine AuNPs in this work had an extremely high catalytic activity toward methylene blue, with a reaction rate constant of 0.21 s(-1) and a TOF value of 1899 h(-1) .

  15. Waveform synthesizer

    Science.gov (United States)

    Franks, Larry A.; Nelson, Melvin A.

    1981-01-01

    A method of producing optical and electrical pulses of desired shape. An optical pulse of arbitrary but defined shape illuminates one end of an array of optical fiber waveguides of differing lengths to time differentiate the input pulse. The optical outputs at the other end of the array are combined to form a synthesized pulse of desired shape.

  16. Fixed-bed column study for hexavalent chromium removal and recovery by short-chain polyaniline synthesized on jute fiber.

    Science.gov (United States)

    Kumar, Potsangbam Albino; Chakraborty, Saswati

    2009-03-15

    Fixed-bed column studies were conducted to evaluate performance of a short-chain polymer, polyaniline, synthesized on the surface of jute fiber (PANI-jute) for the removal of hexavalent chromium [Cr(VI)] in aqueous environment. Influent pH, column bed depth, influent Cr(VI) concentrations and influent flow rate were variable parameters for the present study. Optimum pH for total chromium removal was observed as 3 by electrostatic attraction of acid chromate ion (HCrO(4)(-)) with protonated amine group (NH(3)(+)) of PANI-jute. With increase in column bed depth from 40 to 60 cm, total chromium uptake by PANI-jute increased from 4.14 to 4.66 mg/g with subsequent increase in throughput volume from 9.84 to 12.6L at exhaustion point. The data obtained for total chromium removal were well described by BDST equation till 10% breakthrough. Adsorption rate constant and dynamic bed capacity at 10% breakthrough were observed as 0.01 L/mgh and 1069.46 mg/L, respectively. Adsorbed total chromium was recovered back from PANI-jute as non-toxic Cr(III) after ignition with more than 97% reduction in weight, minimizing the problem of solid waste disposal.

  17. Silver nanowire-carbon fiber cloth nanocomposites synthesized by UV curing adhesive for electrochemical point-of-use water disinfection.

    Science.gov (United States)

    Hong, Xuesen; Wen, Junjie; Xiong, Xuhua; Hu, Yongyou

    2016-07-01

    Novel silver nanowire (AgNW) - carbon fiber cloth (CC) nanocomposites were synthesized by a rapid and facile method. Acting as filter in an electrical gravity filtration device, the AgNW-CC nanocomposites were applied to electrochemical point-of-use water disinfection. AgNW-CC nanocomposites were characterized by FESEM, XRD, and FTIR. Their disinfection performance toward Escherichia coli and bacteriophage MS2 was evaluated by inhibition zone tests, optical density growth curve tests, and flow tests. The results showed that complex 3D AgNW networks with controllable silver release (nanocomposites exhibited excellent intrinsic antibacterial activities against E. coli. The concentration of AgNWs and UV adhesive controlled the released silver and hence led to the change in antibacterial activity. The external electric field significantly enhanced the disinfection efficiency of AgNW-CC nanocomposites. Over 99.999% removal of E. coli and MS2 could be achieved. More complex AgNW networks contributed to higher disinfection efficiency under 10 V and 10(6) CFU (PFU) mL(-1) of microorganism. UV adhesive could keep the disinfection performance from being affected by flow rate. The convenient synthesis and outstanding disinfection performance offer AgNW-CC nanocomposites opportunities in the application of electrochemical point-of-use drinking water disinfection.

  18. Fiducialisation and initial alignment of CLIC component with micrometric accuracy

    CERN Document Server

    Mainaud Durand, Helene; Buzio, Marco; Caiazza, Domenico; Catalan Lasheras, Nuria; Cherif, Ahmed; Doytchinov, Iordan Petrov; Fuchs, Jean-Frederic; Gaddi, Andrea; Galindo Munoz, Natalia; Gayde, Jean-Christophe; Kamugasa, Solomon William; Modena, Michele; Novotny, Peter; Sanz, Claude; Severino, Giordana; Russenschuck, Stephan; Tshilumba, David; Vlachakis, Vasileios; Wendt, Manfred; Zorzetti, Silvia; CERN. Geneva. ATS Department

    2016-01-01

    We propose a new solution to fiducialise the three major components of the CLIC collider: quadrupoles, beam-position monitors (BPM), and accelerating structures (AS). This solution is based on the use of a copper-beryllium (CuBe) wire to locate the reference position, i.e. the symmetry axes of the components (their magnetic, respectively electromagnetic centre axis), and to determine their position in the common support assembly defining a local coordinate system, with respect to the fiducials. These alignment targets will be used later to align the support assembly in the tunnel. With such a method, several accelerator components of different types, supported by a dedicated adjustment system, can be simultaneously fiducialised and pre-aligned using the same wire, enabling a micrometric accuracy with help of a 3D coordinate measurement machine (CMM). Alternative solutions based on frequency scanning interferometry (FSI) and micro-triangulation are also under development, to perform such fiducialisation and in...

  19. Peptide tessellation yields micrometre-scale collagen triple helices

    Science.gov (United States)

    Tanrikulu, I. Caglar; Forticaux, Audrey; Jin, Song; Raines, Ronald T.

    2016-11-01

    Sticky-ended DNA duplexes can associate spontaneously into long double helices; however, such self-assembly is much less developed with proteins. Collagen is the most prevalent component of the extracellular matrix and a common clinical biomaterial. As for natural DNA, the ~103-residue triple helices (~300 nm) of natural collagen are recalcitrant to chemical synthesis. Here we show how the self-assembly of short collagen-mimetic peptides (CMPs) can enable the fabrication of synthetic collagen triple helices that are nearly a micrometre in length. Inspired by the mathematics of tessellations, we derive rules for the design of single CMPs that self-assemble into long triple helices with perfect symmetry. Sticky ends thus created are uniform across the assembly and drive its growth. Enacting this design yields individual triple helices that, in length, match or exceed those in natural collagen and are remarkably thermostable, despite the absence of higher-order association. The symmetric assembly of CMPs provides an enabling platform for the development of advanced materials for medicine and nanotechnology.

  20. A micrometre-sized heat engine operating between bacterial reservoirs

    Science.gov (United States)

    Krishnamurthy, Sudeesh; Ghosh, Subho; Chatterji, Dipankar; Ganapathy, Rajesh; Sood, A. K.

    2016-12-01

    Artificial microscale heat engines are prototypical models to explore the mechanisms of energy transduction in a fluctuation-dominated regime. The heat engines realized so far on this scale have operated between thermal reservoirs, such that stochastic thermodynamics provides a precise framework for quantifying their performance. It remains to be seen whether these concepts readily carry over to situations where the reservoirs are out of equilibrium, a scenario of particular importance to the functioning of synthetic and biological microscale engines and motors. Here, we experimentally realize a micrometre-sized active Stirling engine by periodically cycling a colloidal particle in a time-varying optical potential across bacterial baths characterized by different degrees of activity. We find that the displacement statistics of the trapped particle becomes increasingly non-Gaussian with activity and contributes substantially to the overall power output and the efficiency. Remarkably, even for engines with the same energy input, differences in non-Gaussianity of reservoir noise results in distinct performances. At high activities, the efficiency of our engines surpasses the equilibrium saturation limit of Stirling efficiency, the maximum efficiency of a Stirling engine where the ratio of cold to hot reservoir temperatures is vanishingly small. Our experiments provide fundamental insights into the functioning of micromotors and engines operating out of equilibrium.

  1. The comparison of photocatalytic activity of synthesized TiO{sub 2} and ZrO{sub 2} nanosize onto wool fibers

    Energy Technology Data Exchange (ETDEWEB)

    Moafi, Hadi Fallah [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Shojaie, Abdollah Fallah, E-mail: a.f.shojaie@guilan.ac.ir [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Zanjanchi, Mohammad Ali [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of)

    2010-04-15

    TiO{sub 2} and ZrO{sub 2} nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO{sub 2}-coated and ZrO{sub 2}-coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO{sub 2}-coated and 20-40 nm in size for ZrO{sub 2}-coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO{sub 2} modified sample with respect to that of ZrO{sub 2} for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.

  2. Identification of the electroelastic coupling from full multi-physical fields measured at the micrometre scale

    DEFF Research Database (Denmark)

    Amiot, Fabien; Hild, F.; Kanoufi, F.

    2007-01-01

    Metal coated microcantilevers are used as transducers of their electrochemical environment. Using the metallic layer of these cantilevers as a working electrode allows one to modify the electrochemical state of the cantilever surface. Since the mechanical behaviour of micrometre scale objects is ...

  3. Experiment of Laser Pointing Stability on Different Surfaces to validate Micrometric Positioning Sensor

    CERN Document Server

    AUTHOR|(SzGeCERN)721924; Mainaud Durand, Helene; Piedigrossi, Didier; Sandomierski, Jacek; Sosin, Mateusz; Geiger, Alain; Guillaume, Sebastien

    2014-01-01

    CLIC requires 10 μm precision and accuracy over 200m for the pre-alignment of beam related components. A solution based on laser beam as straight line reference is being studied at CERN. It involves camera/shutter assemblies as micrometric positioning sensors. To validate the sensors, it is necessary to determine an appropriate material for the shutter in terms of laser pointing stability. Experiments are carried out with paper, metal and ceramic surfaces. This paper presents the standard deviations of the laser spot coordinates obtained on the different surfaces, as well as the measurement error. Our experiments validate the choice of paper and ceramic for the shutter of the micrometric positioning sensor. It also provides an estimate of the achievable precision and accuracy of the determination of the laser spot centre with respect to the shutter coordinate system defined by reference targets.

  4. Drive Beam Quadrupoles for the CLIC Project: a Novel Method of Fiducialisation and a New Micrometric Adjustment System

    CERN Document Server

    AUTHOR|(SzGeCERN)411678; Duquenne, Mathieu; Sandomierski, Jacek; Sosin, Mateusz; Rude, Vivien

    2014-01-01

    This paper presents a new method of fiducialisation applied to determine the magnetic axis of the Drive Beam quadrupole of the CLIC project with respect to external alignment fiducials, within a micrometric accuracy and precision. It introduces also a new micrometric adjustment system along 5 Degrees of Freedom, developed for the same Drive Beam quadrupole. The combination of both developments opens very interesting perspectives to get a more simple and accurate alignment of the quadrupoles.

  5. Conductivity and structure of sub-micrometric SrTiO3-YSZ composites

    DEFF Research Database (Denmark)

    Ruiz Trejo, Enrique; Thydén, Karl Tor Sune; Bonanos, Nikolaos;

    2016-01-01

    Sub-micrometric composites of SrTiO3-YSZ (1:1 volume) and samples of SrTiO3 were prepared by high temperature consolidation of precursors obtained by precipitation with NaOH. The structure development and morphology of the precursors were studied by XRD and SEM. The perovskite and fluorite phases...... in the composites are clearly formed at 600°C with no signs of reaction up to 1100°C; the nominally pure SrTiO3 can be formed at temperatures as low as 400°C. Composites with sub-micrometric grain sizes can be prepared successfully without reaction between the components, although a change in the cell parameter...... of the SrTiO3 is attributed to the presence of Na. The consolidated composites were studied by impedance spectroscopy between 200 and 400°C and at a fixed temperature of 600°C with a scan in the partial pressure of oxygen. The composites did not exhibit high levels of ionic conductivity in the grain...

  6. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Quintas, Ignacio; Oujja, Mohamed; Sanz, Mikel; Benitez-Cañete, Antonio [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Chater, Richard J. [Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Cañamares, Maria Vega [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); Marco, José F. [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castllejo@iqfr.csic.es [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2015-02-15

    Highlights: • Micrometric rods obtained by ns pulsed laser deposition of boron carbide at 1064 and 266 nm. • At 1064 nm microrods display crystalline polyhedral shape with sharp edges and flat sides. • Microrods consist of a mixture of boron, boron oxide, boron carbide and aliphatic hydrocarbons. - Abstract: Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved.

  7. Synthesizing Substituted 2-Amino-2-Chromenes Catalyzed by Tertiaryamine-Functionalized Polyacrylonitrile Fiber for Students to Investigate Multicomponent Reactions and Heterogeneous Catalysis

    Science.gov (United States)

    Xie, Yujia; Liu, Xiaoxing; Tao, Minli

    2016-01-01

    A multistep experiment for a synthesis laboratory course that incorporates topics in organic synthesis, chemical analysis, and instrumental analysis was developed. Students prepared a tertiaryamine-functionalized polyacrylonitrile fiber (PAN[subscript T]F), and it was subsequently utilized as an immobilized catalyst in a three-component…

  8. Synthesizing Substituted 2-Amino-2-Chromenes Catalyzed by Tertiaryamine-Functionalized Polyacrylonitrile Fiber for Students to Investigate Multicomponent Reactions and Heterogeneous Catalysis

    Science.gov (United States)

    Xie, Yujia; Liu, Xiaoxing; Tao, Minli

    2016-01-01

    A multistep experiment for a synthesis laboratory course that incorporates topics in organic synthesis, chemical analysis, and instrumental analysis was developed. Students prepared a tertiaryamine-functionalized polyacrylonitrile fiber (PAN[subscript T]F), and it was subsequently utilized as an immobilized catalyst in a three-component…

  9. Unusual micrometric calcite-aragonite interface in the abalone shell Haliotis (Mollusca, Gastropoda).

    Science.gov (United States)

    Dauphin, Yannicke; Cuif, Jean-Pierre; Castillo-Michel, Hiram; Chevallard, Corinne; Farre, Bastien; Meibom, Anders

    2014-02-01

    Species of Haliotis (abalone) show high variety in structure and mineralogy of the shell. One of the European species (Haliotis tuberculata) in particular has an unusual shell structure in which calcite and aragonite coexist at a microscale with small patches of aragonite embedded in larger calcitic zones. A detailed examination of the boundary between calcite and aragonite using analytical microscopies shows that the organic contents of calcite and aragonite differ. Moreover, changes in the chemical composition of the two minerals seem to be gradual and define a micrometric zone of transition between the two main layers. A similar transition zone has been observed between the layers in more classical and regularly structured mollusk shells. The imbrication of microscopic patches of aragonite within a calcitic zone suggests the occurrence of very fast physiological changes in these taxa.

  10. Sub-natural width resonances in Cs vapor confined in micrometric thickness optical cell

    Science.gov (United States)

    Cartaleva, S.; Krasteva, A.; Sargsyan, A.; Sarkisyan, D.; Slavov, D.; Vartanyan, T.

    2013-03-01

    We present here the behavior of Electromagnetically Induced Transparency (EIT), Velocity Selective Optical Pumping (VSOP) resonances and Velocity Selective Excitation (VSE) resonances observed in Cs vapor confined in а micrometric optical cell (MC) with thickness L = 6λ, λ = 852nm. For comparison of behavior of VSE resonance another conventional optical cell with thickness L=2.5 cm is used. Cells are irradiated in orthogonal to their windows directions by probe beam scanned on the Fg = 4 → Fe= 3, 4, 5 set of transitions and pump beam fixed at the Fg = 3 → Fe = 4 transition, on the D2 line of Cs. The enhanced absorption (fluorescence) narrow VSOP resonance at the closed transition transforms into reduced absorption (fluorescence) one with small increase of atomic concentration or light intensity. A striking difference appears between the VSE resonance broadening in L = 6λ and conventional L = 2.5cm cells.

  11. Ground truth of (sub-)micrometre cometary dust – Results of MIDAS onboard Rosetta

    Science.gov (United States)

    Mannel, Thurid; Bentley, Mark; Schmied, Roland; Torkar, Klaus; Jeszenszky, Harald; Romsted, Jens; Levasseur-Regourd, A.; Weber, Iris; Jessberger, Elmar K.; Ehrenfreund, Pascale; Köberl, Christian; Havnes, Ove

    2016-10-01

    The investigation of comet 67P by Rosetta has allowed the comprehensive characterisation of pristine cometary dust particles ejected from the nucleus. Flying alongside the comet at distances as small as a few kilometres, and with a relative velocity of only centimetres per second, the Rosetta payload sampled almost unaltered dust. A key instrument to study this dust was MIDAS (the Micro-Imaging Dust Analysis System), a dedicated atomic force microscope that scanned the surfaces of hundreds of (sub-)micrometre sized particles in 3D with resolutions down to nanometres. This offers the unique opportunity to explore the morphology of smallest cometary dust and expand our current knowledge about cometary material.Here we give an overview of dust collected and analysed by MIDAS and highlight its most important features. These include the ubiquitous agglomerate nature of the dust, which is found at all size scales from the largest (>10 µm) through to the smallest (common cometary origin.

  12. 富碳的含钛碳化硅纤维先驱体的合成%Syntheses of Precursors of Si-Ti-C-O Fibers With Rich Carbon

    Institute of Scientific and Technical Information of China (English)

    王亦菲; 赵鹏; 宋永才; 冯春祥

    2001-01-01

    以聚硅烷(PS)、聚氯乙烯(PVC)和钛酸四丁酯[Ti(OBu)4]合成含碳量不同的聚钛碳硅烷(PTC)先驱体,运用IR、GPC、VPO、TG等分析手段系统地研究了富碳PTC先驱体的合成及其组成结构,讨论了加入PVC含量不同对PTC合成及其结构、性能的影响。经熔融纺丝、不熔化处理、高温烧成制备出具有较好工艺性能和电阻率为100Ω*cm~103Ω*cm的富碳含钛碳化硅纤维(Si-Ti-C-O纤维)。%Polytitanocarbosilanes(PTC) with different C content are synthesized by polysilane(L.PS),polyvinyl chlo-ride(PVC) and Ti(OBu)4.The syntheses,composition and structme of the PTC with rich carbon are studied and the in-fluence of PVC content on the syntheses,composition,structure and properties of PIC is discussed by IR,GPC,VPO,TG.From these precursors,Si-Ti-C-O fibers with specific resistance of 1 Ω*cm ~ 103 Ω*cm are manufactured by melt spin-ning,curing in air and sintering at high temperature.

  13. Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

    Science.gov (United States)

    Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

    2016-01-01

    The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy. PMID:27666316

  14. Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor

    CERN Document Server

    Stern, G; Piedigrossi, D; Sandomierski, J; Sosin, M; Geiger, A; Guillaume, S

    2014-01-01

    Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.

  15. Velocity anisotropy effect in pump-probe spectra of cesium in a micrometric thickness optical cell

    Science.gov (United States)

    Ghosh, P. N.; Mitra, S.; Ray, B.; Krasteva, A.; Slavov, D.; Todorov, P.; Cartaleva, S.

    2015-01-01

    The pump-probe spectra in a cell of micrometric thickness containing cesium vapor are reported. The line shape and nonlinear features observed in the case of fluorescence in the direction parallel to the cell windows and the transmission spectra observed along the propagation direction of the probe beam show considerable differences in the spectral profiles. We observed Electromagnetically Induced Transparency (EIT) and enhanced Velocity Selective Optical Pumping (VSOP) signals. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams will see much lower Doppler shift of incident frequencies and hence will lead to considerable narrowing of the Doppler background in the fluorescence spectra. The coherence decay rate is also low for such atoms as they do not meet with the cell walls. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientation of atomic velocities with respect to the laser beam direction. The simulated curves reproduce the observed sharp EIT peaks and enhanced broad VSOP signals for the closed probe transition in the fluorescence and absorption spectra. The observed effect of the light intensity and temperature change on the non-linear features is reproduced by the simulation.

  16. Sub-micrometre particulate matter is primarily in liquid form over Amazon rainforest

    Science.gov (United States)

    Bateman, Adam P.; Gong, Zhaoheng; Liu, Pengfei; Sato, Bruno; Cirino, Glauber; Zhang, Yue; Artaxo, Paulo; Bertram, Allan K.; Manzi, Antonio O.; Rizzo, Luciana V.; Souza, Rodrigo A. F.; Zaveri, Rahul A.; Martin, Scot T.

    2016-01-01

    Atmospheric particulate matter influences the Earth’s energy balance directly, by altering or absorbing solar radiation, and indirectly by influencing cloud formation. Whether organic particulate matter exists in a liquid, semi-solid, or solid state can affect particle growth and reactivity, and hence particle number, size and composition. The properties and abundance of particles, in turn, influence their direct and indirect effects on energy balance. Non-liquid particulate matter was identified over a boreal forest of Northern Europe, but laboratory studies suggest that, at higher relative humidity levels, particles can be liquid. Here we measure the physical state of particulate matter with diameters smaller than 1 μm over the tropical rainforest of central Amazonia in 2013. A real-time particle rebound technique shows that the particulate matter was liquid for relative humidity greater than 80% for temperatures between 296 and 300 K during both the wet and dry seasons. Combining these findings with the distributions of relative humidity and temperature in Amazonia, we conclude that near-surface sub-micrometre particulate matter in Amazonia is liquid most of the time during both the wet and the dry seasons.

  17. Morphological, structural and micrometric study of cystolith of family acanthaeceae W.S.R. to Kalmegh

    Directory of Open Access Journals (Sweden)

    Switu Jani

    2014-01-01

    Full Text Available Background: Cystoliths are deposition of calcium carbonate found in different parts of plants. Family Acanthaceae is identified by occurrence of cystoliths and presence of acicular crystals of calcium oxalate. Family shows various types of cystoliths which differ from species to species. Aim: A detailed work has been carried out to differentiate plants which are used in Ayurvedic system of medicine belonging to family acanthaceae on basis of structure and size of cystoliths, with special emphasis on the plant Andrographis panniculata Nees (Kalmegha. Materials and Methods: Free-hand sections and leaf surfaces were studied to analyse cystoliths and its types. Micrometric evaluation of cystoliths has been done by taking the mean or average values. Results and Conclusion: Cystoliths usually present in all parts of plant including root while calcium oxalate crystals are largely found to be present in stem - pith region among plants under study. In present study, vasa leaf shows round cystoliths in epidermal region, while in Kalmegha grape bunch-shaped cystoliths were observed in the surface study. Thus it can be conclude that various types of cystoliths can help to differentiate the species belonging to family Acanthaceae.

  18. Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

    Science.gov (United States)

    Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

    2016-09-01

    The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy.

  19. Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon.

    Science.gov (United States)

    Pech, David; Brunet, Magali; Durou, Hugo; Huang, Peihua; Mochalin, Vadym; Gogotsi, Yury; Taberna, Pierre-Louis; Simon, Patrice

    2010-09-01

    Electrochemical capacitors, also called supercapacitors, store energy in two closely spaced layers with opposing charges, and are used to power hybrid electric vehicles, portable electronic equipment and other devices. By offering fast charging and discharging rates, and the ability to sustain millions of cycles, electrochemical capacitors bridge the gap between batteries, which offer high energy densities but are slow, and conventional electrolytic capacitors, which are fast but have low energy densities. Here, we demonstrate microsupercapacitors with powers per volume that are comparable to electrolytic capacitors, capacitances that are four orders of magnitude higher, and energies per volume that are an order of magnitude higher. We also measured discharge rates of up to 200 V s(-1), which is three orders of magnitude higher than conventional supercapacitors. The microsupercapacitors are produced by the electrophoretic deposition of a several-micrometre-thick layer of nanostructured carbon onions with diameters of 6-7 nm. Integration of these nanoparticles in a microdevice with a high surface-to-volume ratio, without the use of organic binders and polymer separators, improves performance because of the ease with which ions can access the active material. Increasing the energy density and discharge rates of supercapacitors will enable them to compete with batteries and conventional electrolytic capacitors in a number of applications.

  20. Ultrahigh-Power Micrometre-Sized Supercapacitors Based on Onion-Like Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Pech, D.; Brunet, M.; Durou, H.; Huang, P.; Mochalin, V.; Gogotsi, Y.; Taberna, P. L.; Simon, P.

    2010-08-15

    Electrochemical capacitors, also called supercapacitors, store energy in two closely spaced layers with opposing charges, and are used to power hybrid electric vehicles, portable electronic equipment and other devices. By offering fast charging and discharging rates, and the ability to sustain millions of cycles, electrochemical capacitors bridge the gap between batteries, which offer high energy densities but are slow, and conventional electrolytic capacitors, which are fast but have low energy densities. Here, we demonstrate microsupercapacitors with powers per volume that are comparable to electrolytic capacitors, capacitances that are four orders of magnitude higher, and energies per volume that are an order of magnitude higher. We also measured discharge rates of up to 200 V s-1, which is three orders of magnitude higher than conventional supercapacitors. The microsupercapacitors are produced by the electrophoretic deposition of a several-micrometre-thick layer of nanostructured carbon onions with diameters of 6–7 nm. Integration of these nanoparticles in a microdevice with a high surface-to-volume ratio, without the use of organic binders and polymer separators, improves performance because of the ease with which ions can access the active material. Increasing the energy density and discharge rates of supercapacitors will enable them to compete with batteries and conventional electrolytic capacitors in a number of applications.

  1. Experimental Comparison of the Effects of Nanometric and Micrometric Particulates on the Tensile Properties and Fracture Behavior of Al Composites at Room and Elevated Temperatures

    Science.gov (United States)

    Ahmed, Adnan; Neely, Andrew J.; Shankar, Krishna

    2011-03-01

    This article studies the influence of nanometric (n-SiCp) and micrometric-scale SiC particulates ( μ-SiCp) on the tensile properties of the Al 7075 alloy. The unreinforced Al and its composites were synthesized using the powder metallurgy (P/M) route and were tested uniaxially in tension at both room and elevated temperatures. Aging behavior was studied to observe any effect of the reinforcement on the aging kinetics and hardness of the composites. X-ray diffraction was performed to determine the crystal structures of the raw materials and any reaction phase formed in the composites. The n-SiCp were not dispersed uniformly in the Al matrix and clustered mainly at the grain boundaries. The stiffness of the composites increased and the ductility decreased with an increase in the volume fraction of the n-SiCp. The n-SiCp proved to be a better reinforcement than the traditional μ-SiCp in terms of imparting higher ductility to the composite. Fractography and microscopy using optical, scanning electron, and transmission electron microscopes were performed for failure and microstructural analysis of all the materials. At room temperature, the fracture altered from ductile in the unreinforced Al to brittle in the composites. At an elevated temperature, the fracture mechanism transformed from brittle to ductile rupture in the composites.

  2. Theoretical and practical feasibility demonstration of a micrometric remotely controlled pre-alignment system for the CLIC linear collider

    CERN Document Server

    Mainaud Durand, H; Chritin, N; Griffet, S; Kemppinen, J; Sosin, M; Touze, T

    2011-01-01

    The active pre-alignment of the Compact Linear Collider (CLIC) is one of the key points of the project: the components must be pre-aligned w.r.t. a straight line within a few microns over a sliding window of 200 m, along the two linacs of 20 km each. The proposed solution consists of stretched wires of more than 200 m, overlapping over half of their length, which will be the reference of alignment. Wire Positioning Sensors (WPS), coupled to the supports to be pre-aligned, will perform precise and accurate measurements within a few microns w.r.t. these wires. A micrometric fiducialisation of the components and a micrometric alignment of the components on common supports will make the strategy of pre-alignment complete. In this paper, the global strategy of active pre-alignment is detailed and illustrated by the latest results demonstrating the feasibility of the proposed solution.

  3. Microstructure and mechanical strength of near- and sub-micrometre grain size copper prepared by spark plasma sintering

    DEFF Research Database (Denmark)

    Zhu, K. N.; Godfrey, A.; Hansen, Niels

    2017-01-01

    Spark plasma sintering (SPS) has been used to prepare fully dense samples of copper in a fully recrystallized condition with grain sizes in the near- and sub-micrometre regime. Two synthesis routes have been investigated to achieve grain size control: (i) SPS at different temperatures from 800 to...... been probed using hardness measurements and tensile testing, revealing an enhanced strength for samples with grain sizes less than ≈ 1 μm....

  4. Biochemical Characterization of the Lactobacillus reuteri Glycoside Hydrolase Family 70 GTFB Type of 4,6-α-Glucanotransferase Enzymes That Synthesize Soluble Dietary Starch Fibers.

    Science.gov (United States)

    Bai, Yuxiang; van der Kaaij, Rachel Maria; Leemhuis, Hans; Pijning, Tjaard; van Leeuwen, Sander Sebastiaan; Jin, Zhengyu; Dijkhuizen, Lubbert

    2015-10-01

    4,6-α-Glucanotransferase (4,6-α-GTase) enzymes, such as GTFB and GTFW of Lactobacillus reuteri strains, constitute a new reaction specificity in glycoside hydrolase family 70 (GH70) and are novel enzymes that convert starch or starch hydrolysates into isomalto/maltopolysaccharides (IMMPs). These IMMPs still have linear chains with some α1→4 linkages but mostly (relatively long) linear chains with α1→6 linkages and are soluble dietary starch fibers. 4,6-α-GTase enzymes and their products have significant potential for industrial applications. Here we report that an N-terminal truncation (amino acids 1 to 733) strongly enhances the soluble expression level of fully active GTFB-ΔN (approximately 75-fold compared to full-length wild type GTFB) in Escherichia coli. In addition, quantitative assays based on amylose V as the substrate are described; these assays allow accurate determination of both hydrolysis (minor) activity (glucose release, reducing power) and total activity (iodine staining) and calculation of the transferase (major) activity of these 4,6-α-GTase enzymes. The data show that GTFB-ΔN is clearly less hydrolytic than GTFW, which is also supported by nuclear magnetic resonance (NMR) analysis of their final products. From these assays, the biochemical properties of GTFB-ΔN were characterized in detail, including determination of kinetic parameters and acceptor substrate specificity. The GTFB enzyme displayed high conversion yields at relatively high substrate concentrations, a promising feature for industrial application. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Biochemical Characterization of the Lactobacillus reuteri Glycoside Hydrolase Family 70 GTFB Type of 4,6-α-Glucanotransferase Enzymes That Synthesize Soluble Dietary Starch Fibers

    Science.gov (United States)

    Bai, Yuxiang; van der Kaaij, Rachel Maria; Leemhuis, Hans; Pijning, Tjaard; van Leeuwen, Sander Sebastiaan; Jin, Zhengyu

    2015-01-01

    4,6-α-Glucanotransferase (4,6-α-GTase) enzymes, such as GTFB and GTFW of Lactobacillus reuteri strains, constitute a new reaction specificity in glycoside hydrolase family 70 (GH70) and are novel enzymes that convert starch or starch hydrolysates into isomalto/maltopolysaccharides (IMMPs). These IMMPs still have linear chains with some α1→4 linkages but mostly (relatively long) linear chains with α1→6 linkages and are soluble dietary starch fibers. 4,6-α-GTase enzymes and their products have significant potential for industrial applications. Here we report that an N-terminal truncation (amino acids 1 to 733) strongly enhances the soluble expression level of fully active GTFB-ΔN (approximately 75-fold compared to full-length wild type GTFB) in Escherichia coli. In addition, quantitative assays based on amylose V as the substrate are described; these assays allow accurate determination of both hydrolysis (minor) activity (glucose release, reducing power) and total activity (iodine staining) and calculation of the transferase (major) activity of these 4,6-α-GTase enzymes. The data show that GTFB-ΔN is clearly less hydrolytic than GTFW, which is also supported by nuclear magnetic resonance (NMR) analysis of their final products. From these assays, the biochemical properties of GTFB-ΔN were characterized in detail, including determination of kinetic parameters and acceptor substrate specificity. The GTFB enzyme displayed high conversion yields at relatively high substrate concentrations, a promising feature for industrial application. PMID:26253678

  6. Heterogeneous freezing of super cooled water droplets in micrometre range- freezing on a chip

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    A new setup to analyse the freezing behaviour of ice nucleation particles (INPs) dispersed in aqueous droplets has been developed with the aim to analyse ensembles of droplets with sizes in the micrometre range, in which INPs are immersed. Major disadvantages of conventional drop-freezing experiments like varying drop sizes or interactions between the water- oil mixture and the INP, were solved by introducing a unique freezing- chip consisting of an etched and sputtered 15x15x1 mm gold-plated silicon or pure gold film (Pummer et al., 2012; Zolles et al., 2015). Using this chip, isolated micrometre-sized droplets can be generated with sizes similar to droplets in real world clouds. The experimental set-up for drop-freezing experiments was revised and improved by establishing automated process control and image evaluation. We were able to show the efficiency and accuracy of our setup by comparing measured freezing temperatures of different INPs (Snomax®, K- feldspar, birch pollen (Betula pendula) washing water, juniper pollen suspension (Juniperus communis) and ultrapure water) with already published results (Atkinson et al., 2013; Augustin et al., 2013; Pruppacher and Klett, 1997; Pummer et al., 2012; Wex et al., 2015; Zolles et al., 2015). Comparison of our measurements with literature data show the important impact of droplet size, INP concentration and number of active sites on the T50 values. Here, the new set-up exhibits its strength in reproducibility and accuracy which is due to the defined and isolated droplets. Finally, it opens a temperature window down to -37˚ C for freezing experiments which was not accessible with former traditional approaches .Atkinson, J. D., Murray, B. J., Woodhouse, M. T., Whale, T. F., Baustian, K. J., Carslaw, K. S., Dobbie, S., O'Sullivan, D., and Malkin, T. L.: The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds (vol 498, pg 355, 2013), Nature, 500, 491-491, 2013. Augustin, S., Wex, H

  7. Visco-acoustic modelling of a vibrating plate interacting with water confined in a domain of micrometric size

    Science.gov (United States)

    Lebental, B.; Bourquin, F.

    2012-04-01

    It is well established that concrete durability strongly depends on the capillary porosity of the material. Hence, structural health monitoring of concrete structure could take advantage of concrete microporosity monitoring. To this end, a new method for the in situ non-destructive testing of capillary porosity in cementitious materials has been proposed. A sensing device that seems well suited to this application is a capacitive ultrasonic transducer with a characteristic size of 1 μm. It is to be embedded in the material. Its vibrating membrane is made of aligned carbon nanotubes forming a thin layer with a typical thickness of 1 nm. It generates acoustic waves of micrometric wavelength into water-filled micropores, aiming at measuring their properties. The present paper focuses on the numerical simulation of the embedded sensor. In order to properly account for viscous effects in fluids at the micrometric scale, we have developed a specific computational method for the visco-acoustic modelling of a microplate vibrating between 10 MHz and 2 GHz in a water-filled domain of micrometric size. Our approach is based on the condensation of the fluid part of the fluid-structure problem on the structure by a finite element method, and on a spectral approximation of the structural equations. The numerical results indicate that the fluid domain is resonant despite the viscous terms, which causes a frequency downshift of the resonances and a decrease of the quality factor. In the coupled system, the plate does not perturb the fluid resonances, whereas the plate resonances are strongly upshifted by the water load. The resonance frequencies of the system are shown to display a clear dependence on the pore width, which makes the device a good candidate as a porosity sensor.

  8. Fiber draw synthesis

    Science.gov (United States)

    Orf, Nicholas D.; Shapira, Ofer; Sorin, Fabien; Danto, Sylvain; Baldo, Marc A.; Joannopoulos, John D.; Fink, Yoel

    2011-01-01

    The synthesis of a high-melting temperature semiconductor in a low-temperature fiber drawing process is demonstrated, substantially expanding the set of materials that can be incorporated into fibers. Reagents in the solid state are arranged in proximate domains within a fiber preform. The preform is fluidized at elevated temperatures and drawn into fiber, reducing the lateral dimensions and bringing the domains into intimate contact to enable chemical reaction. A polymer preform containing a thin layer of selenium contacted by tin–zinc wires is drawn to yield electrically contacted crystalline ZnSe domains of sub-100-nm scales. The in situ synthesized compound semiconductor becomes the basis for an electronic heterostructure diode of arbitrary length in the fiber. The ability to synthesize materials within fibers while precisely controlling their geometry and electrical connectivity at submicron scales presents new opportunities for increasing the complexity and functionality of fiber structures.

  9. Identification of reaction compounds in micrometric layers from gothic paintings using combined SR-XRD and SR-FTIR.

    Science.gov (United States)

    Salvadó, Nati; Butí, Salvador; Nicholson, James; Emerich, Hermann; Labrador, Ana; Pradell, Trinitat

    2009-07-15

    Synchrotron radiation X-ray diffraction (micro-SR-XRD) and Fourier transform infrared spectroscopy (micro-SR-FTIR) are used in the non-destructive identification of reaction and aging compounds from micrometric ancient painting layers. The combination of the micrometer size and non-destructive nature of the techniques together with the high resolution and brilliance of the synchrotron radiation has proved to be a procedure most advantageous for the study of reaction, aging and degradation processes. Copper, lead and calcium carboxylates and oxalates are determined in the chromatic, preparation and alteration layers from 15th century egg tempera and oil paintings. Their nature and crystallinity have been assessed. Some hypothesis about the mechanisms of development of both carboxylates and oxalates are presented.

  10. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres.

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-24

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  11. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  12. Sampling considerations when analyzing micrometric-sized particles in a liquid jet using laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Faye, C.B.; Amodeo, T.; Fréjafon, E. [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France); Delepine-Gilon, N. [Institut des Sciences Analytiques, 5 rue de la Doua, 69100 Villeurbanne (France); Dutouquet, C., E-mail: christophe.dutouquet@ineris.fr [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France)

    2014-01-01

    Pollution of water is a matter of concern all over the earth. Particles are known to play an important role in the transportation of pollutants in this medium. In addition, the emergence of new materials such as NOAA (Nano-Objects, their Aggregates and their Agglomerates) emphasizes the need to develop adapted instruments for their detection. Surveillance of pollutants in particulate form in waste waters in industries involved in nanoparticle manufacturing and processing is a telling example of possible applications of such instrumental development. The LIBS (laser-induced breakdown spectroscopy) technique coupled with the liquid jet as sampling mode for suspensions was deemed as a potential candidate for on-line and real time monitoring. With the final aim in view to obtain the best detection limits, the interaction of nanosecond laser pulses with the liquid jet was examined. The evolution of the volume sampled by laser pulses was estimated as a function of the laser energy applying conditional analysis when analyzing a suspension of micrometric-sized particles of borosilicate glass. An estimation of the sampled depth was made. Along with the estimation of the sampled volume, the evolution of the SNR (signal to noise ratio) as a function of the laser energy was investigated as well. Eventually, the laser energy and the corresponding fluence optimizing both the sampling volume and the SNR were determined. The obtained results highlight intrinsic limitations of the liquid jet sampling mode when using 532 nm nanosecond laser pulses with suspensions. - Highlights: • Micrometric-sized particles in suspensions are analyzed using LIBS and a liquid jet. • The evolution of the sampling volume is estimated as a function of laser energy. • The sampling volume happens to saturate beyond a certain laser fluence. • Its value was found much lower than the beam diameter times the jet thickness. • Particles proved not to be entirely vaporized.

  13. Classification mechanism of the chute, a liquid-phase remover of fines in the micrometre range from a batch of porous particles

    NARCIS (Netherlands)

    Jonker, G.H.; Hoffmann, A.C; Beenackers, A.A C M

    1997-01-01

    A simple and effective classification method, the 'chute', has been developed for the liquid-phase removal of fines from a batch of porous (catalyst) particles in the micrometre range. The chute is a continuous sedimentation fractionator, working in the gravitational field. Equations based an the se

  14. SYNTHESES AND PROPERTIES OF SOME ORGANOSILANE POLYMERS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xinghua; Robert West

    1984-01-01

    Some organosilane polymers with high molecular weights have been synthesized by cocondensation of organosilicon dihalide monomers with sodium metal in toluene. These polymers are both soluble in common solvents and meltable at lower temperatures, and can be molded, cast into films or drawn into fibers. Exposure of the solid polymers to ultraviolet light leads to degradation or crosslinking.

  15. Chemical analyses of micrometre-sized solids by a miniature laser ablation/ionisation mass spectrometer (LMS)

    Science.gov (United States)

    Tulej, Marek; Wiesendanger, Reto; Neuland, Maike; Meyer, Stefan; Wurz, Peter; Neubeck, Anna; Ivarsson, Magnus; Riedo, Valentine; Moreno-Garcia, Pavel; Riedo, Andreas; Knopp, Gregor

    2017-04-01

    Investigation of elemental and isotope compositions of planetary solids with high spatial resolution are of considerable interest to current space research. Planetary materials are typically highly heterogenous and such studies can deliver detailed chemical information of individual sample components with the sizes down to a few micrometres. The results of such investigations can yield mineralogical surface context including mineralogy of individual grains or the elemental composition of of other objects embedded in the sample surface such as micro-sized fossils. The identification of bio-relevant material can follow by the detection of bio-relevant elements and their isotope fractionation effects [1, 2]. For chemical analysis of heterogenous solid surfaces we have combined a miniature laser ablation mass spectrometer (LMS) (mass resolution (m/Dm) 400-600; dynamic range 105-108) with in situ microscope-camera system (spatial resolution ˜2um, depth 10 um). The microscope helps to find the micrometre-sized solids across the surface sample for the direct mass spectrometric analysis by the LMS instrument. The LMS instrument combines an fs-laser ion source and a miniature reflectron-type time-of-flight mass spectrometer. The mass spectrometric analysis of the selected on the sample surface objects followed after ablation, atomisation and ionisation of the sample by a focussed laser radiation (775 nm, 180 fs, 1 kHz; the spot size of ˜20 um) [4, 5, 6]. Mass spectra of almost all elements (isotopes) present in the investigated location are measured instantaneously. A number of heterogenous rock samples containing micrometre-sized fossils and mineralogical grains were investigated with high selectivity and sensitivity. Chemical analyses of filamentous structures observed in carbonate veins (in harzburgite) and amygdales in pillow basalt lava can be well characterised chemically yielding elemental and isotope composition of these objects [7, 8]. The investigation can be

  16. The influence of structure depth on image blurring of micrometres-thick specimens in MeV transmission electron imaging.

    Science.gov (United States)

    Wang, Fang; Sun, Ying; Cao, Meng; Nishi, Ryuji

    2016-04-01

    This study investigates the influence of structure depth on image blurring of micrometres-thick films by experiment and simulation with a conventional transmission electron microscope (TEM). First, ultra-high-voltage electron microscope (ultra-HVEM) images of nanometer gold particles embedded in thick epoxy-resin films were acquired in the experiment and compared with simulated images. Then, variations of image blurring of gold particles at different depths were evaluated by calculating the particle diameter. The results showed that with a decrease in depth, image blurring increased. This depth-related property was more apparent for thicker specimens. Fortunately, larger particle depth involves less image blurring, even for a 10-μm-thick epoxy-resin film. The quality dependence on depth of a 3D reconstruction of particle structures in thick specimens was revealed by electron tomography. The evolution of image blurring with structure depth is determined mainly by multiple elastic scattering effects. Thick specimens of heavier materials produced more blurring due to a larger lateral spread of electrons after scattering from the structure. Nevertheless, increasing electron energy to 2MeV can reduce blurring and produce an acceptable image quality for thick specimens in the TEM.

  17. Comet 81p/Wild 2: The Updated Stardust Coma Dust Fluence Measurement for Smaller (Sub 10-Micrometre) Particles

    Science.gov (United States)

    Price, M. C.; Kearsley, A. T.; Burchell, M. J.; Horz, Friedrich; Cole, M. J.

    2009-01-01

    Micrometre and smaller scale dust within cometary comae can be observed by telescopic remote sensing spectroscopy [1] and the particle size and abundance can be measured by in situ spacecraft impact detectors [2]. Initial interpretation of the samples returned from comet 81P/Wild 2 by the Stardust spacecraft [3] appears to show that very fine dust contributes not only a small fraction of the solid mass, but is also relatively sparse [4], with a low negative power function describing grain size distribution, contrasting with an apparent abundance indicated by the on-board Dust Flux Monitor Instrument (DFMI) [5] operational during the encounter. For particles above 10 m diameter there is good correspondence between results from the DFMI and the particle size inferred from experimental calibration [6] of measured aerogel track and aluminium foil crater dimensions (as seen in Figure 4 of [4]). However, divergence between data-sets becomes apparent at smaller sizes, especially submicrometre, where the returned sample data are based upon location and measurement of tiny craters found by electron microscopy of Al foils. Here effects of detection efficiency tail-off at each search magnification can be seen in the down-scale flattening of each scale component, but are reliably compensated by sensible extrapolation between segments. There is also no evidence of malfunction in the operation of DFMI during passage through the coma (S. Green, personal comm.), so can the two data sets be reconciled?

  18. Engineering a Biocompatible Scaffold with Either Micrometre or Nanometre Scale Surface Topography for Promoting Protein Adsorption and Cellular Response

    Directory of Open Access Journals (Sweden)

    Xuan Le

    2013-01-01

    Full Text Available Surface topographical features on biomaterials, both at the submicrometre and nanometre scales, are known to influence the physicochemical interactions between biological processes involving proteins and cells. The nanometre-structured surface features tend to resemble the extracellular matrix, the natural environment in which cells live, communicate, and work together. It is believed that by engineering a well-defined nanometre scale surface topography, it should be possible to induce appropriate surface signals that can be used to manipulate cell function in a similar manner to the extracellular matrix. Therefore, there is a need to investigate, understand, and ultimately have the ability to produce tailor-made nanometre scale surface topographies with suitable surface chemistry to promote favourable biological interactions similar to those of the extracellular matrix. Recent advances in nanoscience and nanotechnology have produced many new nanomaterials and numerous manufacturing techniques that have the potential to significantly improve several fields such as biological sensing, cell culture technology, surgical implants, and medical devices. For these fields to progress, there is a definite need to develop a detailed understanding of the interaction between biological systems and fabricated surface structures at both the micrometre and nanometre scales.

  19. Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

    Directory of Open Access Journals (Sweden)

    E. Asmi

    2009-12-01

    Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

  20. MORPHOLOGICAL AND MICROMETRICAL CHANGES OF THE PLACENTAL TERMINAL VILLI IN NORMAL AND PREGNANCIES COMPLICATED WITH GESTATIONAL DIABETES MELLITUS

    Directory of Open Access Journals (Sweden)

    Sharmila Bhanu P

    2016-08-01

    Full Text Available AIM & OBJECTIVES Incidence of gestational diabetes mellitus (GDM is escalating in Indian women amounting to 10% of the total pregnancies mainly due to the diet, obesity and sedentary life style. Placenta is a crucial organ of intrauterine life. The functional units of the placenta such as chorionic villi, foetal blood vessels, and the syncytial knots are altered histologically in gestational diabetic condition. The present study is undertaken to observe the morphological and micrometrical changes of the GDM and normal placenta. MATERIAL AND METHODS Total number of 96 placentas, out of which 48 are GDM and 48 from control were procured for the present study. The placentas were collected from our General Hospital, Nellore, AP. Morphology and micrometry of the placentas were studied. RESULTS The shape of placenta was similar in both groups, but the weight in GDM (537.27±131.97 g, diameter (168.2±13.23 mm and thickness (29.9±3.45 mm were significantly (P<0.005 increased when compared to control. The mean number (9.01±2.25 mm3 and diameter (0.08±0.03 mm of the terminal villi and number of foetal blood vessels (21.76±8.52 mm3 were found to be increased in GDM, but the diameter of the blood vessel (0.04±0.02 mm was decreased and highly significant (P<0.001. The syncytial knots and fibrinoid necrosis were also observed in GDM when compared to the normal placenta. CONCLUSION The placentas from GDM were observed with significant morphological and histological changes as compared to controls, which may alter the perinatal outcome resulting in macrosomia, congenital malformations and intrauterine growth retardation.

  1. Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

    Directory of Open Access Journals (Sweden)

    E. Asmi

    2010-05-01

    Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

  2. Supercritical fluid assisted production of micrometric powders of the labile trypsin and chitosan/trypsin composite microparticles.

    Science.gov (United States)

    Shen, Yu-Bin; Guan, Yi-Xin; Yao, Shan-Jing

    2015-07-15

    Supercritical fluid assisted atomization introduced by a hydrodynamic cavitation mixer (SAA-HCM) was used to prepare micrometric particles of a labile protein, i.e., trypsin from aqueous solution without use of any organic solvents. The trypsin particles precipitated had various morphologies under different process conditions, with particle diameters ranging from 0.2 to 4 μm. FTIR, SDS-PAGE, CD and fluorescence spectra were performed to analyze the structural stability of the protein, and trypsin retained above 70% of the biological activity. Besides, chitosan was selected as the polymer carrier in an effort to prepare trypsin composite microparticles via SAA-HCM process. The influences of chitosan molecular weight, polymer/protein ratio and solution concentration on the particle morphology and size distribution were investigated in detail. Non-coalescing spherical composite microparticles with a narrow particle distribution (0.2-3 μm) could be obtained. The SAA-HCM prepared particles were amorphous as demonstrated by XRD and had a loading efficiency about 90%. The protein release profiles of the composite microparticles were evaluated using both the immersion condition and a Franz diffusion cell. Finally, the distribution of the protein within the particles was characterized through CLSM analysis of FITC-labeled trypsin-loaded chitosan microparticles. The SAA-HCM process is demonstrated to be a protein-friendly and promising technique for production of protein and polymer/protein composite particles formulations from aqueous solutions for drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Flower-like CuO synthesized by CTAB-assisted hydrothermal method

    Indian Academy of Sciences (India)

    Yunling Zou; Yan Li; Nan Zhang; Xiulin Liu

    2011-07-01

    Flower-like CuO nanostructures have been synthesized by cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. Here, CuCl2.2H2O was used as copper raw material, and sodium hydroxide was used as precipitate. The resulting CuO powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) pattern exhibited the nanocrystalline nature with monoclinic structure for the as-synthesized nanostructures. FESEM images indicated that the flower-like CuO nanostructures are composed of many interconnected nanosheets in size of several micrometres in length and width and 60–80 nm in thickness. The possible formation mechanism of flower-like CuO nanostructures was discussed.

  4. Green syntheses, v.1

    CERN Document Server

    Tundo, Pietro

    2014-01-01

    Introduction to the Green Syntheses SeriesPietro Tundo and John AndraosApplication of Material Efficiency Metrics to Assess Reaction Greenness-Illustrative Case Studies from Organic SynthesesJohn AndraosReaction 1: Synthesis of 3-Benzyl-5-Methyleneoxazolidin-2-one from N-Benzylprop-2-yn-1-Amine and CO2Qing-Wen Song and Liang-Nian HeReaction 2: Synthesis of the 5-Membered Cyclic Carbonates from Epoxides and CO2Qing-Wen Song, Liang-Nian HePart I: Green Methods for the Epoxidation of

  5. Mechanisms of formation of sub- and micrometre-scale holes in thin metal films by single nano- and femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, P A; Zayarnyi, D A; Ionin, A A; Kudryashov, S I; Makarov, S V; Rudenko, A A; Yurovskikh, V I [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Kulchin, Yu N; Vitrik, O B; Kuchmizhak, A A [Institute for Automation and Control Processes, Far-Eastern Branch, Russian Academy of Sciences, Vladivostok (Russian Federation); Drozdova, E A; Odinokov, S B [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)

    2014-06-30

    Mechanisms of formation of sub- and micrometre-scale holes in thin silver and chromium films of variable thickness by tightly-focused single nanosecond IR laser pulses with fluences in the range of 10 – 10{sup 4} J cm{sup -2} are studied by means of optical and scanning electron microscopy. At the minimal fluences above 5 J cm{sup -2}, the micrometre (2 – 5 μm in radius) holes are produced in these films, accompanying the lateral heat conduction in the film during the pump laser pulse, cavitation at the metallic/glass interface and subsequent explosive removal of the molten film. At the fluences of ∼1 – 10 kJ cm{sup -2} much larger (20 – 40 μm in radius) holes are formed in the film as a result of its heating by the erosive surface microplasma through the lateral heat conduction in the film during the plasma lifetime of the order of a few microseconds. Finally, at the maximal fluences (well above 10 kJ cm{sup -2}), the submillimetre holes were produced in these films by intense shock waves, generated in the erosive microplasmas. The comparative analysis of the formation mechanisms for sub- and micrometrescale holes in the same thin metal films by the single nano- and femtosecond laser pulses is provided. (extreme light fields and their applications)

  6. Fiber diffraction without fibers.

    Science.gov (United States)

    Poon, H-C; Schwander, P; Uddin, M; Saldin, D K

    2013-06-28

    Postprocessing of diffraction patterns of completely randomly oriented helical particles, as measured, for example, in so-called "diffract-and-destroy" experiments with an x-ray free electron laser can yield "fiber diffraction" patterns expected of fibrous bundles of the particles. This will allow "single-axis alignment" to be performed computationally, thus obviating the need to do this by experimental means such as forming fibers and laser or flow alignment. The structure of such particles may then be found by either iterative phasing methods or standard methods of fiber diffraction.

  7. Synthesized night vision goggle

    Science.gov (United States)

    Zhou, Haixian

    2000-06-01

    A Synthesized Night Vision Goggle that will be described int his paper is a new type of night vision goggle with multiple functions. It consists of three parts: main observing system, picture--superimposed system (or Cathode Ray Tube system) and Charge-Coupled Device system.

  8. Surface modification and characterization of aramid fibers with hybrid coating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianrui; Zhu, Yaofeng; Ni, Qingqing; Fu, Yaqin, E-mail: fyq01@zstu.edu.cn; Fu, Xiang

    2014-12-01

    Graphical abstract: - Highlights: • Aramid fibers modification sizing synthesized by sol–gel in the absence of water. • The strength and interfacial adhesion property of modified fibers were improved. • Modified fibers show a special surface structure. • The mechanism explains the function of structure. - Abstract: Aramid fibers were modified through solution dip-coating and interfacial in situ polymerization using a newly synthesized SiO{sub 2}/shape memory polyurethane (SiO{sub 2}/SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO{sub 2}/SMPU hybrid successfully coated the fiber surface. The surface morphology of the aramid fibers and the single fiber tensile strength and interfacial shear strength (IFSS) of the composites were determined. The IFSS of the fiber coated with the hybrid improved by 45%, which benefited from a special “pizza-like” structure on the fiber surface.

  9. Tensile and oxidation behavior of SiC fibers; Comportement en traction et en oxydation de fibres SiC

    Energy Technology Data Exchange (ETDEWEB)

    Cabet, C.; Bosonnet, S.; Robin, C.; Pasquier, S.; Duprey, B. [CEA Saclay, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse 91 - Gif-sur-Yvette (France); Colin, C.; Maxel, M.; Gelebart, L. [CEA Saclay, DEN, DMN, SRMA, Laboratoire d' Etude du Comportement Mecanique des Materiaux, 91 - Gif-sur-Yvette (France)

    2011-10-26

    In support of the development of SiC/SiC composite materials for fuel cladding in a Gas-cooled Fast Reactor, micrometric silicon carbide-based fibers with low residual oxygen were investigated in the reactor operating environment. A dedicated machine enabled to slow tensile strain single fibers from room temperature up to 1700 C under secondary vacuum. It was observed that fibers are brittle and their mechanical properties drop when the temperature is increased. In addition, thermogravimetric analysis was performed at 1100 C under helium with an oxygen partial pressure of 20 Pa. Fibers oxidized and the reaction rate appeared to be globally parabolic after about 60 h. Electronic microscopy confirmed that a thin silicon-oxide scale has been formed on the fiber surface. Future work includes studying the effect of oxidation on the fiber tensile behavior. (authors)

  10. Gadolinium-loaded chitosan nanoparticles for neutron-capture therapy: Influence of micrometric properties of the nanoparticles on tumor-killing effect.

    Science.gov (United States)

    Ichikawa, Hideki; Uneme, Takeshi; Andoh, Tooru; Arita, Yuya; Fujimoto, Takuya; Suzuki, Minoru; Sakurai, Yoshinori; Shinto, Hiroyuki; Fukasawa, Tomonori; Fujii, Fumihiko; Fukumori, Yoshinobu

    2014-06-01

    As a nanoparticulate device for controlled delivery of Gd in NCT, the authors have developed gadolinium-loaded chitosan nanoparticles (Gd-nanoCPs). In the present study, influence of micrometric properties such as particle size, particle-surface charge and Gd content of Gd-nanoCPs on tumor-killing effect by Gd-NCT was investigated with Gd-nanoCPs. Two types of Gd-nanoCPs with different mean particle size, zeta potential and Gd-content (Gd-nanoCP-400; 391nm, 28mV, 9wt% and Gd-nanoCP-200; 214nm, 19mV, 24wt%) could be prepared by using chitosans with different molecular weights. Gd-nanoCPs incorporating 1.2mg of natural Gd were injected intratumorally once or twice to mice subcutaneously-bearing B16F10 melanoma. Eight hours after the last administration, thermal neutron was irradiated to tumor region of the mice. Remarkable tumor-growth was observed in both hot and cold control groups. In contrast, Gd-NCT groups showed significant tumor-growth suppression effect, though their efficacy was found to depend on the micrometric properties of Gd-nanoCPs. In particular, the Gd-nanoCP-200 exhibited stronger tumor-killing effect than the Gd-nanoCP-400 at the same Gd dose and it was still similar to Gd-nanoCP-400 in tumor-growth suppressing effect even at the half of Gd dose of Gd-nanoCP-400. This significance in tumor-killing effect would be ascribed from a higher Gd retention in the tumor tissue and an improved distribution of Gd with intratumorally administered Gd-nanoCP-200. Indeed, the Gd concentration in tumor tissue at the time corresponding to the onset of thermal neutron irradiation was determined to be significantly higher in Gd-nanoCP-200, compared with Gd-nanoCP-400. These results demonstrated that appropriate modification of Gd-nanoCPs in micrometric properties would be an effective way to improve the retention of Gd in the tumor tissue after intratumoral injection, leading to the enhanced tumor-killing effect in Gd-NCT.

  11. Sub micrometric fibrillar structures of codoped poly aniline obtained by co-oxidation using the NaCl O/ammonium peroxydisulfate system: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Osorio F, J. E.; Gomez Y, C.; Hernandez P, M. A.; Corea T, M. L., E-mail: josorio@ipn.mx [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, U. P. Adolfo Lopez Mateos, Av. Instituto Politecnico Nacional s/n, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)

    2013-07-01

    A mixture of ammonium peroxydisulfate and sodium hypochlorite (NaCl O) (co-oxi dating system) were used to obtain poly aniline (PANi) doped with HCl and camphorsulfonic acid (CsA) (co-doping). The effect of HCl/CsA ratio added during polymerization structure, morphology and electrical conductivity of the conducting polymer was investigated. When NaCl O is used, the polymerization rate is substantially increased and the morphology changes from micrometric granular to nano metric fibrillar. CsA was used as complementary dopant but also to improve the solubility of PANi in common solvents. However, results suggest that quinone-like heterocycles containing carbonyl radicals as well as phenazine-type aromatic rings might be impeding an efficient doping in detriment of the conductivity. For the characterization X-Ray diffraction analysis, UV visible spectroscopy and scanning electron microscopy were used. (Author)

  12. Fiber biology

    Science.gov (United States)

    Cotton fiber cells arising from seed epidermis is the most important agricultural textile commodity in the world. To produce fully mature fibers, approximately two months of fiber developmental process are required. The timing of four distinctive fiber development stages consisting of initiation, ...

  13. Nonlinear fiber optics formerly quantum electronics

    CERN Document Server

    Agrawal, Govind

    1995-01-01

    The field of nonlinear fiber optics has grown substantially since the First Edition of Nonlinear Fiber Optics, published in 1989. Like the First Edition, this Second Edition is a comprehensive, tutorial, and up-to-date account of nonlinear optical phenomena in fiber optics. It synthesizes widely scattered research material and presents it in an accessible manner for students and researchers already engaged in or wishing to enter the field of nonlinear fiber optics. Particular attention is paid to the importance of nonlinear effects in the design of optical fiber communication systems. This is

  14. Method for synthesizing HMX

    Science.gov (United States)

    McGuire, Raymond R.; Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.

    1984-01-01

    A method and apparatus for electrochemically synthesizing N.sub.2 O.sub.5 cludes oxidizing a solution of N.sub.2 O.sub.4 /HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /HNO.sub.3 solution and the anode. A potential of about 1.35 to 2.0 V vs. SCE is preferred, while a potential of about 1.80 V vs. SCE is most preferred. Thereafter, the N.sub.2 O.sub.5 is reacted with either 1.5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) to form cyclotetramethylenetetraamine (HMX).

  15. Synchronization of Fourier-Synthesized Optical Pulses to a Mode-Locked Optical Clock

    Institute of Scientific and Technical Information of China (English)

    Masaharu; Hyodo; Kazi; Sarwal; Abedin; Noriaki; Onodera; Masayoshi; Watanabe

    2003-01-01

    A Fourier-synthesized 40-GHz optical pulse train was successfully synchronized to an 8-GHz optical clock generated from a mode-locked fiber ring laser. The measured timing jitter of the synchronization was 0.43 ps.

  16. PREPARATION AND CATALYTIC ACTIVITY OF BIOACTIVE FIBERS

    Institute of Scientific and Technical Information of China (English)

    Yu-yuan Yao; Wen-xing Chen; Bao-yan Zhao; Shen-shui Lü

    2006-01-01

    Two kinds of water-soluble metallophthalocyanines, binuclear cobalt phthalocyanine (Co2Pc2) and binuclear ferric phthalocyanine (Fe2Pc2), were synthesized through phenylanhydride-urea route and characterized by elemental analysis and FT-IR spectra. Binuclear metallophthalocyanine derivatives (Mt2Pc2) were immobilized on silk fibers and modified viscose fibers to construct bioactive fibers of mimic enzyme. Mt2Pc2 was used as the active center ofbioactive fibers, viscose and silk fibers as the microenvironments. The catalytic oxidation ability of bioactive fibers on the malodors of methanthiol and hydrogen sulfide was investigated at room temperature. The experimental results indicated that the catalytic activity of such bioactive fibers was closely correlative to the types ofbioactive fibers and substrates.

  17. Doclet To Synthesize UML

    Science.gov (United States)

    Barry, Matthew R.; Osborne, Richard N.

    2005-01-01

    The RoseDoclet computer program extends the capability of Java doclet software to automatically synthesize Unified Modeling Language (UML) content from Java language source code. [Doclets are Java-language programs that use the doclet application programming interface (API) to specify the content and format of the output of Javadoc. Javadoc is a program, originally designed to generate API documentation from Java source code, now also useful as an extensible engine for processing Java source code.] RoseDoclet takes advantage of Javadoc comments and tags already in the source code to produce a UML model of that code. RoseDoclet applies the doclet API to create a doclet passed to Javadoc. The Javadoc engine applies the doclet to the source code, emitting the output format specified by the doclet. RoseDoclet emits a Rose model file and populates it with fully documented packages, classes, methods, variables, and class diagrams identified in the source code. The way in which UML models are generated can be controlled by use of new Javadoc comment tags that RoseDoclet provides. The advantage of using RoseDoclet is that Javadoc documentation becomes leveraged for two purposes: documenting the as-built API and keeping the design documentation up to date.

  18. Dietary Fiber

    Science.gov (United States)

    Fiber is a substance in plants. Dietary fiber is the kind you eat. It's a type of carbohydrate. You may also see it listed on a food label as soluble ... types have important health benefits. Good sources of dietary fiber include Whole grains Nuts and seeds Fruit and ...

  19. Fiber Amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten

    2017-01-01

    The chapter provides a discussion of optical fiber amplifiers and through three sections provides a detailed treatment of three types of optical fiber amplifiers, erbium doped fiber amplifiers (EDFA), Raman amplifiers, and parametric amplifiers. Each section comprises the fundamentals including t...

  20. Water Fibers

    CERN Document Server

    Douvidzon, Mark L; Martin, Leopoldo L; Carmon, Tal

    2016-01-01

    Fibers constitute the backbone of modern communication and are used in laser surgeries; fibers also genarate coherent X-ray, guided-sound and supercontinuum. In contrast, fibers for capillary oscillations, which are unique to liquids, were rarely considered in optofluidics. Here we fabricate fibers by water bridging an optical tapered-coupler to a microlensed coupler. Our water fibers are held in air and their length can be longer than a millimeter. These hybrid fibers co-confine two important oscillations in nature: capillary- and electromagnetic-. We optically record vibrations in the water fiber, including an audio-rate fundamental and its 3 overtones in a harmonic series, that one can hear in soundtracks attached. Transforming Micro-Electro-Mechanical-Systems [MEMS] to Micro-Electro-Capillary-Systems [MECS], boosts the device softness by a million to accordingly improve its response to minute forces. Furthermore, MECS are compatible with water, which is a most important liquid in our world.

  1. Sub-micrometre holotomographic characterisation of the effects of solution heat treatment on an AlMg7.3Si3.5 alloy.

    Science.gov (United States)

    Tolnai, D; Requena, G; Cloetens, P; Lendvai, J; Degischer, H P

    2012-07-30

    A strip cast AlMg7.3Si3.5 alloy is investigated by sub-micrometre holotomographic analysis achieving a voxel size of (60 nm)(3) by cone beam magnification of the focused synchrotron beam using Kirkpatrick-Baez mirrors. The three-dimensional microstructure of the same specimen volume in the as-cast state is compared with that after exposure to 540 °C for 30 min resolving microstructural features down to 180 nm. The three-dimensional analysis of the architecture of the eutectic Mg2Si and the Fe-aluminides reveals how the as-cast microstructure changes during the solution treatment. The alloy in the as-cast condition contains a highly interconnected seaweed-like Mg2Si eutectic. The level of three-dimensional interconnectivity of the Mg2Si eutectic phase decreases by only partial disintegration during the heat treatment correcting the two-dimensional metallographic impression of isolated round particles. Statistical analyses of the particle distribution, sphericity, mean curvatures and Gaussian curvatures describe quantitatively the architectural changes of the Mg2Si phase. This explains the decrease of the high temperature strength of the alloy by the solution treatment tested in hot compression.

  2. Observation and theoretical simulation of electromagnetically induced transparency and enhanced velocity selective optical pumping in cesium vapour in a micrometric thickness optical cell

    Science.gov (United States)

    Krasteva, A.; Ray, B.; Slavov, D.; Todorov, P.; Ghosh, P. N.; Mitra, S.; Cartaleva, S.

    2014-09-01

    Observation of electromagnetically induced transparency (EIT) and enhanced velocity selective optical pumping (VSOP) signals in a micrometric cell with cesium is reported. The line shape and non-linear features observed in the case of fluorescence in the direction parallel to the cell windows and the transmission spectra observed along the propagation direction of the probe beam show considerable differences in the spectral profile. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientations of atomic velocities with respect to the laser beam direction. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams have much lower Doppler shift and hence produce considerable narrowing of the Doppler background in the fluorescence spectra. The coherence decay rate is also low for such atoms as they do not meet with the cell walls. The simulated curves reproduce the observed sharp EIT peaks and enhanced broad VSOP signals for the closed probe transition in the fluorescence and absorption spectra. The observed effect of detuning of the pump frequency on the non-linear features is also reproduced by the simulation.

  3. Thermal diffusivity measurements on a single fiber with micro-scale diameter at very high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Pradere, C.; Batsale, J.C. [TREFLE, UMR 8508, Esplanade des Arts et Metiers, 33405 Talence (France); Goyheneche, J.M.; Pailler, R. [LCTS, UMR 5801, 3 allee de La Boetie, 33600 Pessac (France); Dilhaire, S. [CPMOH, UMR 5798, 351 cours de la Liberation, 33405 Talence (France)

    2006-05-15

    The objective of this work is to measure the thermal diffusivity of single carbon and ceramic fibers at very high temperature. The difficulty of the measurement is due to the micrometric scale of the fiber ({approx_equal} 10 {mu}m) and the important range of temperature (700-2700 K). An original periodic technique is developed. Based on a 1D analytical direct models and using both magnitude and phase shift measurements, it allows accurate results from simulated experiments. A device is designed in order to maintain the fiber at uniform high temperature. A small perturbation is imposed by a laser beam and the temperature response is analysed. A complete study of the numerical identification allows an estimation of the uncertainty due to the numerical process. For a {+-} {sigma} standard deviation on experimental measurements, the thermal diffusivity is estimated with a {+-} {sigma}/80 uncertainty. Measurements on both low and high conductive materials validate the apparatus and the estimation method. (author)

  4. Diode Pumped Fiber Laser.

    Science.gov (United States)

    1984-12-01

    FIBER LASERS I. Nd:YAG FIBER LASER FABRICATION .............. 5 A. FIBER GROWTH .......................... 5 B. FIBER PROCESSING 7...1.32 pm FIBER LASERS I. Nd:YAG FIBER LASER FABRICATION A. FIBER GROWTH The single crystal fibers used in this work were grown at Stanford University

  5. Two Fiber Optical Fiber Thermometry

    Science.gov (United States)

    Jones, Mathew R.; Farmer, Jeffery T.; Breeding, Shawn P.

    2000-01-01

    An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.

  6. Synthesis of silicon carbide fiber using blend of polycarbosilane and hydroxy-terminated-polybutadiene as precursor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yiming; Yang, Shujin; Lu, Yi; Liu, Xinwei; Tan, Zilie (National Univ. of Defence Technology (China))

    1989-01-01

    SiC fiber was synthesized using a blend of polycarbosilane (PC) and the proper amount of hydroxy-terminated polybutadiene (HTPB) precursor. When the blend is used as a precursor to synthesize the SiC fiber, PC and HTPB will react to form a cross-linked polymer at about 260 C. So, less oxygen is needed in curing the precursor fiber, and less silicon dioxide is in the SiC fiber. The strength of SiC fiber is higher. Using the blend of PC and 3 wt pct HTPB as precursor, the strength of SiC fiber increases by about 26 percent.

  7. RAMESES publication standards: realist syntheses

    Directory of Open Access Journals (Sweden)

    Wong Geoff

    2013-01-01

    Full Text Available Abstract Background There is growing interest in realist synthesis as an alternative systematic review method. This approach offers the potential to expand the knowledge base in policy-relevant areas - for example, by explaining the success, failure or mixed fortunes of complex interventions. No previous publication standards exist for reporting realist syntheses. This standard was developed as part of the RAMESES (Realist And MEta-narrative Evidence Syntheses: Evolving Standards project. The project's aim is to produce preliminary publication standards for realist systematic reviews. Methods We (a collated and summarized existing literature on the principles of good practice in realist syntheses; (b considered the extent to which these principles had been followed by published syntheses, thereby identifying how rigor may be lost and how existing methods could be improved; (c used a three-round online Delphi method with an interdisciplinary panel of national and international experts in evidence synthesis, realist research, policy and/or publishing to produce and iteratively refine a draft set of methodological steps and publication standards; (d provided real-time support to ongoing realist syntheses and the open-access RAMESES online discussion list so as to capture problems and questions as they arose; and (e synthesized expert input, evidence syntheses and real-time problem analysis into a definitive set of standards. Results We identified 35 published realist syntheses, provided real-time support to 9 on-going syntheses and captured questions raised in the RAMESES discussion list. Through analysis and discussion within the project team, we summarized the published literature and common questions and challenges into briefing materials for the Delphi panel, comprising 37 members. Within three rounds this panel had reached consensus on 19 key publication standards, with an overall response rate of 91%. Conclusion This project used multiple

  8. On the mechanical role of de novo synthesized elastin in the urinary bladder wall.

    Science.gov (United States)

    Wognum, Silvia; Schmidt, David E; Sacks, Michael S

    2009-10-01

    The urinary bladder wall (UBW), which is composed of smooth muscle, collagen, and elastin, undergoes profound remodeling in response to changes in mechanical loading resulting from various pathologies. In our laboratory, we have observed the production of fibrillar elastin in the extracellular matrix (ECM), which makes the UBW a particularly attractive tissue to investigate smooth muscle tissue remodeling. In the present study, we explored the mechanical role that de novo elastin fibers play in altering UBW ECM mechanical behavior using a structural constitutive modeling approach. The mechanical behavior of the collagen fiber component of the UBW ECM was determined from the biaxial stress-stretch response of normal UBW ECM, based on bimodal fiber recruitment that was motivated by the UBW's unique collagen fiber structure. The resulting fiber ensemble model was then combined with an experimentally derived fiber angular distribution to predict the biaxial mechanical behavior of normal and the elastin-rich UBW ECM to elucidate the underlying mechanisms of elastin production. Results indicated that UBW ECM exhibited a distinct structure with highly coiled collagen fiber bundles and visible elastic fibers in the pathological situation. Elastin-rich UBW ECM had a distinct mechanical behavior with higher compliance, attributable to the indirect effect of elastin fibers contracting the collagen fiber network, resulting in a retracted unloaded reference state of the tissue. In conclusion, our results suggest that the urinary bladder responds to prolonged periods of high strain by increasing its effective compliance through the interaction between collagen and de novo synthesized elastic fibers.

  9. Vacuum fiber-fiber coupler

    Science.gov (United States)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe

    2017-02-01

    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  10. Dietary fiber.

    Science.gov (United States)

    Madar, Z; Thorne, R

    1987-01-01

    Studies done on dietary fiber (DF) over the past five years are presented in this Review. The involvement of dietary fiber in the control of plasma glucose and lipid levels is now established. Two dietary fiber sources (soybean and fenugreek) were studied in our laboratory and are discussed herein. These sources were found to be potentially beneficial in the reduction of plasma glucose in non-insulin dependent diabetes mellitus subjects. They are shown to be acceptable by human subjects and are easy to use either in a mixture of milk products and in cooking. The mechanism by which dietary fiber alters the nutrient absorption is also discussed. The effect of DF on gastric emptying, transit time, adsorption and glucose transport may contribute to reducing plasma glucose and lipid levels. DF was found to be effective in controlling blood glucose and lipid levels of pregnant diabetic women. Dietary fiber may also be potentially beneficial in the reduction of exogenous insulin requirements in these subjects. However, increased consumption of DF may cause adverse side effects; the binding capabilities of fiber may affect nutrient availability, particularly that of minerals and prolonged and high DF dosage supplementation must be regarded cautiously. This is particularly true when recommending such a diet for pregnant or lactating women, children or subjects with nutritional disorders. Physiological effects of DF appear to depend heavily on the source and composition of fiber. Using a combination of DF from a variety of sources may reduce the actual mass of fiber required to obtain the desired metabolic effects and will result in a more palatable diet. Previously observed problems, such as excess flatus, diarrhea and mineral malabsorption would also be minimized.

  11. Frequency synthesizers concept to product

    CERN Document Server

    Chenakin, Alexander

    2011-01-01

    A frequency synthesizer is an electronic system for generating any of a range of frequencies from a single fixed oscillator. They are found in modern devices like radio receivers, mobile phones, and GPS systems. This comprehensive resource offers RF and microwave engineers a thorough overview of both well-established and recently developed frequency synthesizer design techniques. Professionals find expert guidance on all design aspects, including main architectures, key building blocks, and practical circuit implementation. Engineers learn the development process and gain a solid understanding

  12. X-Band PLL Synthesizer

    OpenAIRE

    P. Kutin; Vagner, P.

    2006-01-01

    This paper deals with design and realization of a PLL synthesizer for the microwave X−band. The synthesizer is intended for use as a local oscillator in a K−band downconverter. The design goal was to achieve very low phase noise and spurious free signal with a sufficient power level. For that purpose a low phase noise MMIC VCO was used in phase locked loop. The PLL works at half the output frequency, therefore there is a frequency doubler at the output of the PLL. The output signal ...

  13. Multimode interference-based fiber sensor in a cavity ring-down system for refractive index measurement

    Science.gov (United States)

    Silva, Susana; Frazão, Orlando

    2017-06-01

    This work reports a multimode interference-based fiber sensor in a cavity ring-down system (CRD) for sensing temperature-induced refractive index (RI) changes of water. The sensing head is based in multimodal interference (MMI) and it is placed inside the fiber loop cavity of the CRD system. A modulated laser source was used to send pulses down into the fiber loop cavity and an erbium-doped fiber amplifier (EDFA) was placed in the fiber ring to provide an observable signal with a reasonable decay time. The behavior of the sensing head to temperature was studied due to its intrinsic sensitivity to said parameter - a sensitivity of -1.6×10-9 μs/°C was attained. This allowed eliminating the temperature component from RI measurement of water and a linear sensitivity of 580 μs/RIU in the RI range of 1.324-1.331 was obtained. The use of a MMI fiber sensor in the proposed CRD configuration allowed achieving a sensitivity ∼4-fold than that obtained with a tilted fiber Bragg grating and ∼2-fold than that when a micrometric channel inscribed in the fiber was used.

  14. Template-synthesized opal hydrogels

    Institute of Scientific and Technical Information of China (English)

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  15. Laboratory Syntheses of Insect Pheromones.

    Science.gov (United States)

    Cormier, Russell A.; Hoban, James N.

    1984-01-01

    Provides background information and procedures for the multi-step synthesis of tiger moth and boll weevil pheromones (sex attractants). These syntheses require several laboratory periods. The tiger moth pheromone synthesis is suitable for introductory organic chemistry while the boll weevil pheromone is recommended for an advanced laboratory…

  16. Information Retrieval for Ecological Syntheses

    Science.gov (United States)

    Bayliss, Helen R.; Beyer, Fiona R.

    2015-01-01

    Research syntheses are increasingly being conducted within the fields of ecology and environmental management. Information retrieval is crucial in any synthesis in identifying data for inclusion whilst potentially reducing biases in the dataset gathered, yet the nature of ecological information provides several challenges when compared with…

  17. Laboratory Syntheses of Insect Pheromones.

    Science.gov (United States)

    Cormier, Russell A.; Hoban, James N.

    1984-01-01

    Provides background information and procedures for the multi-step synthesis of tiger moth and boll weevil pheromones (sex attractants). These syntheses require several laboratory periods. The tiger moth pheromone synthesis is suitable for introductory organic chemistry while the boll weevil pheromone is recommended for an advanced laboratory…

  18. Soluble vs. insoluble fiber

    Science.gov (United States)

    Insoluble vs. soluble fiber; Fiber - soluble vs. insoluble ... There are 2 different types of fiber -- soluble and insoluble. Both are important for health, digestion, and preventing diseases. Soluble fiber attracts water and turns to gel during digestion. ...

  19. Photovoltaic fibers

    Science.gov (United States)

    Gaudiana, Russell; Eckert, Robert; Cardone, John; Ryan, James; Montello, Alan

    2006-08-01

    It was realized early in the history of Konarka that the ability to produce fibers that generate power from solar energy could be applied to a wide variety of applications where fabrics are utilized currently. These applications include personal items such as jackets, shirts and hats, to architectural uses such as awnings, tents, large covers for cars, trucks and even doomed stadiums, to indoor furnishings such as window blinds, shades and drapes. They may also be used as small fabric patches or fiber bundles for powering or recharging batteries in small sensors. Power generating fabrics for clothing is of particular interest to the military where they would be used in uniforms and body armor where portable power is vital to field operations. In strong sunlight these power generating fabrics could be used as a primary source of energy, or they can be used in either direct sunlight or low light conditions to recharge batteries. Early in 2002, Konarka performed a series of proof-of-concept experiments to demonstrate the feasibility of building a photovoltaic cell using dye-sensitized titania and electrolyte on a metal wire core. The approach taken was based on the sequential coating processes used in making fiber optics, namely, a fiber core, e.g., a metal wire serving as the primary electrode, is passed through a series of vertically aligned coating cups. Each of the cups contains a coating fluid that has a specific function in the photocell. A second wire, used as the counter electrode, is brought into the process prior to entering the final coating cup. The latter contains a photopolymerizable, transparent cladding which hardens when passed through a UV chamber. Upon exiting the UV chamber, the finished PV fiber is spooled. Two hundred of foot lengths of PV fiber have been made using this process. When the fiber is exposed to visible radiation, it generates electrical power. The best efficiency exhibited by these fibers is 6% with an average value in the 4

  20. X-Band PLL Synthesizer

    Directory of Open Access Journals (Sweden)

    P. Kutin

    2006-04-01

    Full Text Available This paper deals with design and realization of a PLL synthesizer for the microwave X−band. The synthesizer is intended for use as a local oscillator in a K−band downconverter. The design goal was to achieve very low phase noise and spurious free signal with a sufficient power level. For that purpose a low phase noise MMIC VCO was used in phase locked loop. The PLL works at half the output frequency, therefore there is a frequency doubler at the output of the PLL. The output signal from the frequency doubler is filtered by a band-pass filter and finally amplified by a single stage amplifier.

  1. Solid phase syntheses of oligoureas

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)

    1997-02-19

    Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.

  2. Synthesis of Cotton from Tossa Jute Fiber and Comparison with Original Cotton

    Directory of Open Access Journals (Sweden)

    Md. Mizanur Rahman

    2015-01-01

    Full Text Available Cotton fibers were synthesized from tossa jute and characteristics were compared with original cotton by using FTIR and TGA. The FTIR results indicated that the peak intensity of OH group from jute cotton fibers occurred at 3336 cm−1 whereas the peak intensity of original cotton fibers occurred at 3338 cm−1. This indicated that the synthesized cotton fiber properties were very similar to the original cotton fibers. The TGA result showed that maximum rate of mass loss, the onset of decomposition, end of decomposition, and activation energy of synthesized cotton were higher than original cotton. The activation energy of jute cotton fibers was higher than the original cotton fibers.

  3. Fiber resources

    Science.gov (United States)

    P. J. Ince

    2004-01-01

    In economics, primary inputs or factors of production define the term ‘resources.’ Resources include land resources (plants, animals, and minerals), labor, capital, and entrepreneurship. Almost all pulp and paper fiber resources are plant materials obtained from trees or agricultural crops. These resources encompass plant materials harvested directly from the land (...

  4. Method of synthesizing silica nanofibers using sound waves

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Jaswinder K.; Datskos, Panos G.

    2015-09-15

    A method for synthesizing silica nanofibers using sound waves is provided. The method includes providing a solution of polyvinyl pyrrolidone, adding sodium citrate and ammonium hydroxide to form a first mixture, adding a silica-based compound to the solution to form a second mixture, and sonicating the second mixture to synthesize a plurality of silica nanofibers having an average cross-sectional diameter of less than 70 nm and having a length on the order of at least several hundred microns. The method can be performed without heating or electrospinning, and instead includes less energy intensive strategies that can be scaled up to an industrial scale. The resulting nanofibers can achieve a decreased mean diameter over conventional fibers. The decreased diameter generally increases the tensile strength of the silica nanofibers, as defects and contaminations decrease with the decreasing diameter.

  5. Method of synthesizing silica nanofibers using sound waves

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Jaswinder K.; Datskos, Panos G.

    2017-08-08

    A method for synthesizing silica nanofibers using sound waves is provided. The method includes providing a solution of polyvinyl pyrrolidone, adding sodium citrate and ammonium hydroxide to form a first mixture, adding a silica-based compound to the solution to form a second mixture, and sonicating the second mixture to synthesize a plurality of silica nanofibers having an average cross-sectional diameter of less than 70 nm and having a length on the order of at least several hundred microns. The method can be performed without heating or electrospinning, and instead includes less energy intensive strategies that can be scaled up to an industrial scale. The resulting nanofibers can achieve a decreased mean diameter over conventional fibers. The decreased diameter generally increases the tensile strength of the silica nanofibers, as defects and contaminations decrease with the decreasing diameter.

  6. Method of synthesizing silica nanofibers using sound waves

    Science.gov (United States)

    Sharma, Jaswinder K.; Datskos, Panos G.

    2015-09-15

    A method for synthesizing silica nanofibers using sound waves is provided. The method includes providing a solution of polyvinyl pyrrolidone, adding sodium citrate and ammonium hydroxide to form a first mixture, adding a silica-based compound to the solution to form a second mixture, and sonicating the second mixture to synthesize a plurality of silica nanofibers having an average cross-sectional diameter of less than 70 nm and having a length on the order of at least several hundred microns. The method can be performed without heating or electrospinning, and instead includes less energy intensive strategies that can be scaled up to an industrial scale. The resulting nanofibers can achieve a decreased mean diameter over conventional fibers. The decreased diameter generally increases the tensile strength of the silica nanofibers, as defects and contaminations decrease with the decreasing diameter.

  7. Design of optocoupler for synthesizing four color spectra

    Science.gov (United States)

    Liu, Zechun; Ge, Aiming; Tao, Xinran; Yang, Shengqi; Wang, Tianyi

    2016-07-01

    LEDs with the advantage of high luminous efficacy and long life time show the potential of replacing traditional luminaire. Most commercial white LED light sources use blue or ultraviolet chip coated with emitting phosphor, but the sensitivity and instability of such phosphors has become a big issue. The typical RGB-LED by using individual chips has the problem of spatial separation and insufficient spectral overlap which leads to low CRI. This study suggests a novel and high-efficiency design of fiber optical optocoupler to synthesize four colors emitted by separate LEDs to provide the ideal light sources by adjusting the individual LEDs separately. By choosing different colored light to be synthesized, this optocoupler can be used as light sources which can be highly controlled to offer the best lighting conditions. Compared with other widely used commercial LED sources, this new design of light sources can be used in special experiments which require multi-spectral light.

  8. Reinforced Sisal Fiber with Ferric Nitrate Composites

    Directory of Open Access Journals (Sweden)

    Asif Jehan

    2015-06-01

    Full Text Available Ferric oxide synthesized through annealing route. The present research work deals with ferrite composite prepared using chemical reactions. Ferric nitrates and ammonium chloride doped with sisal fiber has been prepared. The structural behavior of aluminum oxide was studied in XRD, SEM, TEM, FTIR & dielectric measurement. This behavior showed ferrite nature of the sample.

  9. Synthesized Optimization of Triangular Mesh

    Institute of Scientific and Technical Information of China (English)

    HU Wenqiang; YANG Wenyu

    2006-01-01

    Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.

  10. Physiologically driven avian vocal synthesizer

    Science.gov (United States)

    Sitt, Jacobo D.; Arneodo, Ezequiel M.; Goller, Franz; Mindlin, Gabriel B.

    2010-03-01

    In this work, we build an electronic syrinx, i.e., a programmable electronic device capable of integrating biomechanical model equations for the avian vocal organ in order to synthesize song. This vocal prosthesis is controlled by the bird’s neural instructions to respiratory and the syringeal motor systems, thus opening great potential for studying motor control and its modification by sensory feedback mechanisms. Furthermore, a well-functioning subject-controlled vocal prosthesis can lay the foundation for similar devices in humans and thus provide directly health-related data and procedures.

  11. Method of synthesizing tungsten nanoparticles

    Science.gov (United States)

    Thoma, Steven G; Anderson, Travis M

    2013-02-12

    A method to synthesize tungsten nanoparticles has been developed that enables synthesis of nanometer-scale, monodisperse particles that can be stabilized only by tetrahydrofuran. The method can be used at room temperature, is scalable, and the product concentrated by standard means. Since no additives or stabilizing surfactants are required, this method is particularly well suited for producing tungsten nanoparticles for dispersion in polymers. If complete dispersion is achieved due to the size of the nanoparticles, then the optical properties of the polymer can be largely maintained.

  12. Smart polymer fibers with shape memory effect

    Science.gov (United States)

    Ji, Feng Long; Zhu, Yong; Lian Hu, Jin; Liu, Yan; Yeung, Lap-Yan; Dou Ye, Guang

    2006-12-01

    In this study, a series of smart polymer fibers with a shape memory effect were developed. Firstly, a set of shape memory polyurethanes with varying hard-segment content were synthesized. Then, the solutions of the shape memory polyurethanes were spun into fibers through wet spinning. The thin films of the polyurethanes were considered to represent the nature of the polyurethanes. Differential scanning calorimetry tests were performed on both the thin films and the fibers to compare their thermal properties. Wide angle x-ray diffraction and small angle x-ray scattering techniques were applied to investigate the structure of the thin films and the fibers, and the structure change taking place in the spinning process was therefore revealed. The spinning process resulted in the polyurethane molecules being partially oriented in the direction of the fiber axis. The molecular orientation prompted the aggregation of the hard segments and the formation of hard-segment microdomains. The mechanical properties of the fibers were examined through tensile tests. The shape memory effect of the thin films and the fibers was investigated through a series of thermomechanical cyclic tensile tests. It was found that the fibers showed less shape fixity but more shape recovery compared with the thin films. Further investigations revealed that the recovery stress of the fibers was higher than that of the thin films. The smart fibers may exert the recovery force of shape memory polymers to an extreme extent in the direction of the fiber axis and therefore provide a possibility for producing high-performance actuators.

  13. Asymmetric Syntheses Aided by Biocatalysts

    Institute of Scientific and Technical Information of China (English)

    陈沛然; 顾建新; 魏志亮; 韩世清; 李祖义; 林国强

    2003-01-01

    This article summarizes the achievements of the authors' group in the area of biocatalyst-catalyzed organic reactions in recent 10 years. A strain of Geotrichum sp. obtained by screeninu is capable of stereoselectlvely reducing a number of carbonyl compounds. In many cases, the stermghemistry is complementary with that obtained by baker' s yeast. Therefore, this microorganism provides a useful pathway to the preparation of alcohol eompounds with specific configurations. On the other hand, a nmmber of plant sourees have been screened for oxynitrilases and the hydrocyanation reactions of various arylcarboxalde-hydes have been investigated.A"micro-aqueous reaction system" was invented,by which a serles of novel optically active cyanohydrins were prepared.On this hasis,a high through-put comtimasous reaction system has been designed.This paper also deseribes examples of the syntheses of bio-active compounds by using the optieally active compounds obtained from the above mentioned catalytic reactions as precursors.

  14. Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

    2015-06-15

    Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

  15. RF SYNTHESIZER WITH DIRECT DIGITAL SYNTHESIZ

    Directory of Open Access Journals (Sweden)

    V. V. Murav’iov

    2014-01-01

    Full Text Available A synthesizer of frequencies with direct digital synthesis and a frequency multiplier on PLL are developed. Phase noises of an output signal of the synthesizer, noise of a loop of PLL, level of collateral radiations on outputs of the digital synthesizer (frequency of 100 MHz and the frequency multiplier output on a loop of PLL (frequency of 8 GHz are probed.

  16. Synthesis of silicon carbide fiber from blended precursor of organosilicon polymers

    Energy Technology Data Exchange (ETDEWEB)

    Narisawa, Masaki; Kitano, Shuhei; Okamura, Kiyohito [Osaka Prefecture Univ., Sakai (Japan); Itoh, Masayoshi [Mitsui Toatsu Chemicals, Inc., Yokohama (Japan). Central Research Lab.

    1995-12-01

    Polycarbosilane (PCS) containing 10% of polyvinylsilane (PVS) was prepared and shaped into fiber form by the melt-spinning method. The influence of the PVS addition on curing and pyrolysis processes for the precursor fiber was investigated. The addition of PVS to PCS can lower the curing temperature and increase the residual weight of the fiber during pyrolysis. The silicon carbide fiber synthesized from the blended precursor maintains higher strength than the fiber from pure PCS beyond 1,673 K. The core of the SiC fiber from blended precursor maintains a homogeneous appearance even after surface degradation.

  17. Synthese de champs sonores adaptative

    Science.gov (United States)

    Gauthier, Philippe-Aubert

    La reproduction de champs acoustiques est une approche physique au probleme technologique de la spatialisation sonore. Cette these concerne l'aspect physique de la reproduction de champs acoustiques. L'objectif principal est l'amelioration de la reproduction de champs acoustiques par "synthese de champs acoustiques" ("Wave Field Synthesis", WFS), une approche connue, basee sur des hypotheses de champ libre, a l'aide du controle actif par l'ajout de capteurs de l'erreur de reproduction et d'une boucle fermee. Un premier chapitre technique (chapitre 4) expose les resultats d'appreciation objective de la WFS par simulations et mesures experimentales. L'effet indesirable de la salle de reproduction sur les qualites objectives de la WFS fut illustre. Une premiere question de recherche fut ensuite abordee (chapitre 5), a savoir s'il est possible de reproduire des champs progressifs en salle dans un paradigme physique de controle actif: cette possibilite fut prouvee. L'approche technique privilegiee, "synthese de champs adaptative" ("Adaptive Wave Field Synthesis" [AWFS]), fut definie, puis simulee (chapitre 6). Cette approche d'AWFS comporte une originalite en controle actif et en reproduction de champs acoustiques: la fonction cout quadratique representant la minimisation des erreurs de reproduction inclut une regularisation de Tikhonov avec solution a priori qui vient de la WFS. L'etude de l'AWFS a l'aide de la decomposition en valeurs singulieres (chapitre 7) a permis de comprendre les mecanismes propres a l'AWFS. C'est la deuxieme principale originalite de la these. L'algorithme FXLMS (LMS et reference filtree) est modifie pour l'AWFS (chapitre 8). Le decouplage du systeme par decomposition en valeurs singulieres est illustre dans le domaine du traitement de signal et l'AWFS basee sur le controle independant des modes de rayonnement est simulee (chapitre 8). Ce qui constitue la troisieme originalite principale de cette these. Ces simulations du traitement de signal

  18. Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Barkou, Stig Eigil; Broeng, Jes; Bjarklev, Anders Overgaard

    1999-01-01

    Photonic bandgap fibers are describes using a new Kagomé cladding structure. These fibers may potentially guide light in low-index regions. Such fibers offer new dispersion properties, and large design flexibility.......Photonic bandgap fibers are describes using a new Kagomé cladding structure. These fibers may potentially guide light in low-index regions. Such fibers offer new dispersion properties, and large design flexibility....

  19. FUNCTIONAL POLYHYDROXYALKANOATES SYNTHESIZED BY MICROORGANISMS

    Institute of Scientific and Technical Information of China (English)

    Guo-qiang Chen; Qiong Wu; Kai Zhao; Peter H.Yu

    2000-01-01

    Many bacteria have been found to synthesize a family of polyesters termed polyhydroxyalkanoate, abbreviated as PHA. Some interesting physical properties of PHAs such as piezoelectricity, non-linear optical activity, biocompatibility and biodegradability offer promising applications in areas such as degradable packaging, tissue engineering and drug delivery.Over 90 PHAs with various structure variations have been reported and the number is still increasing. The mechanical property of PHAs changes from brittle to flexible to elastic, depending on the side-chainlength of PHA. Many attempts have been made to produce PHAs as biodegradable plastics using various microorganisms obtained from screening natural environments, genetic engineering and mutation. Due to the high production cost, PHAs still can not compete with the nondegradable plastics, such as polyethylene and polypropylene. Various processes have been developed using low cost raw materials for fermentation and an inorganic extraction process for PHA purification. However, a super PHA production strain may play the most critical role for any large-scale PHA production. Our recent study showed that PHA synthesis is a common phenomenon among bacteria inhabiting various locations, especially oil-contaminated soils. This is very important for finding a suitable bacterial strain for PHA production. In fact, PHA production strains capable of rapid growth and rapid PHA synthesis on cheap molasses substrate have been found on molasses contaminated soils. A combination of novel properties and lower cost will allow easier commercialization of PHA for many applications.

  20. Optical fiber modulator derivates from hollow optical fiber with suspended core.

    Science.gov (United States)

    Yang, Xinghua; Liu, Yanxin; Tian, Fengjun; Yuan, Libo; Liu, Zhihai; Luo, Shenzi; Zhao, Enming

    2012-06-01

    A fiber optic integrated modulation-depth-tunable modulator based on a type of hollow optical fiber with suspended core is proposed and investigated. We synthesized magnetic fluid containing superparamagnetic Fe(3)O(4) nanoparticles and encapsulated it in the hollow optical fiber as the cladding layer of the suspended core by fusing the hollow optical fiber with the multimode optical fibers. The light with a wavelength of 632.8 nm is coupled in and out of the modulating element by a tapering technique. Experimental results show that the light attenuation in the system can be greatly influenced by only 2.0×10(-2) μL of the magnetic fluid under different magnetic field strengths. The saturated modulation depth is 43% when the magnetic field strength is 489 Oe. The response time of the system is fiber modulators, including other integrated electro-optic devices, such as optical switch, optical fiber filter, and magnetic sensors utilizing the special structure of this hollow optical fiber with suspended core and superparamagnetic magnetic fluid.

  1. Carbon nanotube fibers spun from a sizing material

    Science.gov (United States)

    Meng, Fancheng; Lu, Weibang; Li, Qingwen; Claes, Michaël; Kchit, Nadir; Chou, Tsu-Wei

    2014-12-01

    Carbon nanotube (CNT) fibers with large pores of hundreds of nanometers in diameter are synthesized from a commercially available sizing material. The pore size can be well controlled by varying the processing conditions including fiber drying temperature and shrinkage ratio. With the use of small amount H2SO4 (1 wt. %), low-concentration (1 wt. %) polyvinyl alcohol (PVA) bath coagulated porous fibers are flexible, with both high mechanical strength and electrical conductivity. Ethylene glycol/methanol mixture bath is also used to fabricate PVA-free porous CNT fibers. The porous fiber demonstrates good performance in foreign components accessing and accommodating, which may facilitate more CNT fiber practical applications, such as absorbents and supercapacitors.

  2. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D;

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  3. Photonic crystal fibers -

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou

    2002-01-01

    During this ph.d. work, attention has been focused on understanding and analyzing the modal behavior of micro-structured fibers. Micro-structured fibers are fibers with a complex dielectric toplogy, and offer a number of novel possibilities, compared to standard silica based optical fibers. The t...

  4. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Hokyung; Kim; Jinchae; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  5. Preparation and characterization of poly(vinyl alcohol)/graphene nanofibers synthesized by electrospinning

    Science.gov (United States)

    Barzegar, Farshad; Bello, Abdulhakeem; Fabiane, Mopeli; Khamlich, Saleh; Momodu, Damilola; Taghizadeh, Fatemeh; Dangbegnon, Julien; Manyala, Ncholu

    2015-02-01

    We report on the synthesis and characterization of electrospun polyvinyl alcohol (PVA)/graphene nanofibers. The samples produced were characterized by Raman spectroscopy for structural and defect density analysis, scanning electron microscopy (SEM) for morphological analysis, and thermogravimetric (TGA) for thermal analysis. SEM measurements show uniform hollow PVA fibers formation and excellent graphene dispersion within the fibers, while TGA measurements show the improved thermal stability of PVA in the presence of graphene. The synthesized polymer reinforced nanofibers have potential to serve in many different applications such as thermal management, supercapacitor electrodes and biomedical materials for drug delivery.

  6. High power fiber lasers

    Institute of Scientific and Technical Information of China (English)

    LOU Qi-hong; ZHOU Jun

    2007-01-01

    In this review article, the development of the double cladding optical fiber for high power fiber lasers is reviewed. The main technology for high power fiber lasers, including laser diode beam shaping, fiber laser pumping techniques, and amplification systems, are discussed in de-tail. 1050 W CW output and 133 W pulsed output are ob-tained in Shanghai Institute of Optics and Fine Mechanics, China. Finally, the applications of fiber lasers in industry are also reviewed.

  7. Preparation and Properties of Antibacterial Lyocell Fibers Containing Chitosan Derivative

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Xu-pin; LIU Xiao-fei; CHENG Bo-wen; KANG Wei-min

    2006-01-01

    The O-carboxymethyl chitosan sodium salt, NaCMCh, was initially synthesized and analyzed with better antibacterial activity than chitosan. Then NaCMCh was dissolved in the N-methylmorpholine-N- oxide, NMMO, solution with cellulose for spinning of the lyocell fiber. The results showed that the lyocell fibers modified with over 2 wt% NaCMCh has good antibacterial activity in against the E. coli and with NaCMCh content below 6 wt% has considerable mechanical properties.

  8. Synthesizing Regression Results: A Factored Likelihood Method

    Science.gov (United States)

    Wu, Meng-Jia; Becker, Betsy Jane

    2013-01-01

    Regression methods are widely used by researchers in many fields, yet methods for synthesizing regression results are scarce. This study proposes using a factored likelihood method, originally developed to handle missing data, to appropriately synthesize regression models involving different predictors. This method uses the correlations reported…

  9. 52-GHz Millimetre-Wave PLL Synthesizer

    OpenAIRE

    Lee, Ja-Yol; Yu, Hyun-Kyu

    2010-01-01

    In this chapter, we design and fabricate a 52GHz frequency synthesizer for 60GHz dualconversion receiver using SiGe BiCMOS process technology. The designed PLL-based frequency synthesizer consists of a 26-GHz PLL and a 52-GHz frequency doubler. In the

  10. A Novel Route of Furan Compounds Syntheses

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of compounds that contained furan skeletons were synthesized using 3,4-bis(trimethylsilyl)furan as staring material. 1H NMR, 13C NMR, MS and EA had identified these new molecules. The important factors that influenced reactions were discussed, and the new furan intermediates could be used in various organic syntheses.

  11. "Comments on Slavin": Synthesizing Causal Inferences

    Science.gov (United States)

    Briggs, Derek C.

    2008-01-01

    When causal inferences are to be synthesized across multiple studies, efforts to establish the magnitude of a causal effect should be balanced by an effort to evaluate the generalizability of the effect. The evaluation of generalizability depends on two factors that are given little attention in current syntheses: construct validity and external…

  12. Composites comprising biologically-synthesized nanomaterials

    Science.gov (United States)

    Curran, Seamus; Dias, Sampath; Blau, Werner; Wang, Jun; Oremland, Ronald S; Baesman, Shaun

    2013-04-30

    The present disclosure describes composite materials containing a polymer material and a nanoscale material dispersed in the polymer material. The nanoscale materials may be biologically synthesized, such as tellurium nanorods synthesized by Bacillus selenitireducens. Composite materials of the present disclosure may have optical limiting properties and find use in optical limiting devices.

  13. Amplitude-modulated fiber-ring laser

    DEFF Research Database (Denmark)

    Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter

    2000-01-01

    Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self-starting......Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...

  14. Amplitude-modulated fiber-ring laser

    DEFF Research Database (Denmark)

    Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter

    2000-01-01

    Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self-starting......Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...

  15. Optical Fiber Fusion Splicing

    CERN Document Server

    Yablon, Andrew D

    2005-01-01

    This book is an up-to-date treatment of optical fiber fusion splicing incorporating all the recent innovations in the field. It provides a toolbox of general strategies and specific techniques that the reader can apply when optimizing fusion splices between novel fibers. It specifically addresses considerations important for fusion splicing of contemporary specialty fibers including dispersion compensating fiber, erbium-doped gain fiber, polarization maintaining fiber, and microstructured fiber. Finally, it discusses the future of optical fiber fusion splicing including silica and non-silica based optical fibers as well as the trend toward increasing automation. Whilst serving as a self-contained reference work, abundant citations from the technical literature will enable readers to readily locate primary sources.

  16. Biomaterials based on N,N,N-trimethyl chitosan fibers in wound dressing applications.

    Science.gov (United States)

    Zhou, Zhongzheng; Yan, Dong; Cheng, Xiaojie; Kong, Ming; Liu, Ya; Feng, Chao; Chen, Xiguang

    2016-08-01

    In the present work, N,N,N-trimethyl chitosan (TMC) fibers were synthesized successfully and the resulting quaternized materials were characterized by FTIR. The designed TMC fibers with different degree of quaternization achieved high water absorption capability. In antibacterial activity study, TMC fibers showed high antibacterial activity than chitosan fibers against the gram-negative bacteria Escherichia coli (>63%) and gram-positive bacteria Staphylococcus aureus (>99%). TMC fibers exhibited no obvious cytotoxicity to mouse embryo fibroblast cells with low extraction concentrations (<0.05g/mL). In animal wound healing test, TMC2 fibers could significantly enhance wound re-epithelialization and contraction compared with the control (chitosan fibers). In conclusion, TMC fibers have a potential to be used as wound dressing materials.

  17. PULP FIBER SIZE CHARACTERIZATION

    Institute of Scientific and Technical Information of China (English)

    Shijie Liu

    2004-01-01

    Pulp fiber length distribution characterization has been examined in this study. Because of the fiber morphology: slender in shape, fiber size distribution characterization is a very difficult task. Traditional technique involves separation of the particles by size,such as Bauer-McNett fiber classifier, and measuring the weight fractions. The particle fractions obtained may or may not reflect the desired size classification.On the other hand, the more recent technique through optical measurement of fiber length is limited by its inability to measure the mass of the particle fractions.Therefore, not only the two techniques fail to generate identical results, either one was accepted to be of better value. Pure hardwood kraft, softwood kraft, and their mixture samples have been measured for their fiber length distributions using an optical fiber quality analyzer: FQA. The data obtained from FQA are extensively studied to investigate more reliable way of representing the fiber length data and thus examining the viable route for measuring the fiber size distributions. It has been found that the fiber length averaged length 11 is a viable indicator of the average pulp fiber length. The fiber size fraction and/or distribution can be represented by the fiber "length" fractions.

  18. SYNTHESIZED EXPECTED BAYESIAN METHOD OF PARAMETRIC ESTIMATE

    Institute of Scientific and Technical Information of China (English)

    Ming HAN; Yuanyao DING

    2004-01-01

    This paper develops a new method of parametric estimate, which is named as "synthesized expected Bayesian method". When samples of products are tested and no failure events occur, thedefinition of expected Bayesian estimate is introduced and the estimates of failure probability and failure rate are provided. After some failure information is introduced by making an extra-test, a synthesized expected Bayesian method is defined and used to estimate failure probability, failure rateand some other parameters in exponential distribution and Weibull distribution of populations. Finally,calculations are performed according to practical problems, which show that the synthesized expected Bayesian method is feasible and easy to operate.

  19. Synthesis of polypiperazine-amide thin-film membrane on PPESK hollow fiber UF membrane

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new interfacial polymerization (IP) procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber ultrafiltration (UF) membrane. A hollow fiber composite membrane with good performance was prepared and studied by FT-IR and scanning electron microscopy.

  20. Methane Decomposition into Carbon Fibers over Coprecipitated Nickel-Based Catalysts

    Institute of Scientific and Technical Information of China (English)

    Yan Ju; Fengyi Li; Renzhong Wei

    2005-01-01

    Decomposition of methane in the presence of coprecipitated nickel-based catalysts to produce carbon fibers was investigated. The reaction was studied in the temperature range of 773 K to 1073 K.At 1023 K, the catalytic activities of three catalysts kept high at the initial period and then decreased with the reaction time. The lifetimes of Ni-Cu-Al and Ni-La-Al catalysts are longer than that of Ni-Al catalyst. With three catalysts, the yield of carbon fibers was very low at 773 K. The yield of carbon fibers for Ni-La-Al catalyst was more than those for Ni-Al and Ni-Cu-Al catalysts. For Ni-La-Al catalyst, the elevation of temperature from 873 K up to 1073 K led gradually to an increase in the yield of carbon fibers.XRD studies on the Ni-La-Al catalyst indicate that La2NiO4 was formed. The formation of La2NiO4 is responsible for the increase in the catalytic lifetime and the yield of carbon fibers synthesized on Ni-La-Al at 773-1073 K. Carbon fibers synthesized on Ni-Al catalyst are thin, long carbon nanotubes. There are bamboo-shaped carbon fibers synthesized on Ni-Cu-Al catalyst. Carbon fibers synthesized on Ni-La-Al catalyst have large hollow core, thin wall and good graphitization.

  1. Characterization of defects of mullite fibers prepared by polyvinyl butyral as spinning aid

    OpenAIRE

    2010-01-01

    Mullite fibers have been synthesized using polyvinyl butyral as spinning aids. Defects including cracks, core-sheath structure, randomly arranged powders, shots and rough surface were observed. The results showed that circumferential cracks were terminated by the main axial crack. The thermal shrinkage could be considered as the reason for the formation of cracks and core-sheath structure. Improper control of heat treatment resulted in the rough surface around fibers. The wet gel fibers...

  2. Conductivity and Ambient Stability of Halogen-Doped Carbon Nanotube Fibers

    Science.gov (United States)

    Gaier, J. R.; Chirino, C. M.; Chen, M.; Waters, D. L.; Tran, Mai Kim; Headrick, R.; Young, C. C.; Tsentalovich, D.; Whiting, B.; Pasquali, M.; Waarbeek, Ron ter; Otto, Marcin J.

    2014-01-01

    Carbon nanotube fibers were fabricated using a variety of spinning conditions and post-spinning processing with the goal of creating a high-conductivity yet environmentally stable fiber. These fiber variants were then doped with bromine, iodine, iodine chloride, or iodine bromide and their electrical and microstructural properties were characterized. Environmentally stable compounds were synthesized with electrical conductivity greater than 50,000 Scm.

  3. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead...... of doping, use a microstructure of air and glass to obtain a refractive index difference between the core and the cladding. This air/glass microstructure lends the photonic crystal fibers a range of unique and highly usable properties, which are very different from those found in solid standard fibers....... The freedom to design the dispersion profile of the fibers is much larger and it is possible to create fibers, which support only a single spatial mode, regardless of wavelength. In comparison, the standard dispersion-shifted fibers are limited by a much lower index-contrast between the core and the cladding...

  4. Glass Fibers: Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Edith Mäder

    2017-02-01

    Full Text Available Since the early 1930s, the process of melting glass and subsequently forming fibers, in particular discontinuous fiber glass or continuous glass filaments, evolved into commercial-scale manufacturing.[...

  5. Fiber Optics Technology.

    Science.gov (United States)

    Burns, William E.

    1986-01-01

    Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

  6. Fiber Optics Instrumentation Development

    Science.gov (United States)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  7. A universal isocyanide for diverse heterocycle syntheses

    NARCIS (Netherlands)

    Patil, Pravin; Dömling, Alexander; Khoury, Kareem; Herdtweck, Eberhardt

    2014-01-01

    Novel scaffolds are of uttermost importance for the discovery of functional material. Three different heterocyclic scaffolds easily accessible from isocyanoacetaldehyde dimethylacetal 1 by multicomponent reaction (MCR) are described. They can be efficiently synthesized by a Ugi tetrazole multicompon

  8. Raman assisted lightwave synthesized frequency sweeper

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2010-01-01

    We present a Lightwave Synthesized Frequency Sweeper comprising a Raman amplifier for loss compensation. The generated pulse train contains 123 pulses and has a flat signal level as well as a low noise level....

  9. Progress in synthesizing functional nano materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ With the consistent investment, the research team directed by Prof. Yadong Li of Chemistry Department of Tsinghua University achieved new progress in synthesizing nano materials with specific functions. The research team led by Prof.

  10. Syntheses and Functional Properties of Phthalocyanines

    Directory of Open Access Journals (Sweden)

    Keiichi Sakamoto

    2009-08-01

    Full Text Available Metal phthalocyanine tetrasulfonic acids, metal phthalocyanine octacarboxylic acids, metal octakis(hexyloxymethylphthalocyanines, and metal anthraquinocyanines have been synthesized. Then, zinc bis(1,4-didecylbenzo-bis(3,4-pyridoporphyrazines, the cyclotetramerization products of a 1:1 mixture of 3,6-didecylphthalonitrile and 3,4-dicyanopyridine, were synthesized. Futher, subphthalocyanine and its derivatives, with substituents such as thiobutyl and thiophenyl moieties were synthesized. Electrochemical measurements were performed on the abovementioned phthalocyanine derivatives and analogues in order to examine their electron transfer abilities and electrochemical reaction mechanisms in an organic solvent. Moreover, 1,4,8,11,15,18,22,25-octakis(thiophenylmethyl phthalocyanes were synthesized. The Q-bands of the latter compounds appeared in the near-infrared region. Furthermore, non-colored transparent films in the visible region can be produced.

  11. SYNTHESES AND PROPERTIES OF POLYMERIZABLE METALLOPHTHALOCYANINE DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    LIU Yunqi; YAMADA Akira; SHIGEHARA Kiyotaka; HARA Masahiko

    1988-01-01

    Metallophthalocyanine derivatives with polymerizable vinyl groups were synthesized, characterized and polymerized. Preliminary results on their Langmuir-Blodgett (LB) film formation and the electronic properties of (Indium-Tin Oxide/LB-film/Al) Schottky devices were reported.

  12. The Trajectory Synthesizer Generalized Profile Interface

    Science.gov (United States)

    Lee, Alan G.; Bouyssounouse, Xavier; Murphy, James R.

    2010-01-01

    The Trajectory Synthesizer is a software program that generates aircraft predictions for Air Traffic Management decision support tools. The Trajectory Synthesizer being used by researchers at NASA Ames Research Center was restricted in the number of trajectory types that could be generated. This limitation was not sufficient to support the rapidly changing Air Traffic Management research requirements. The Generalized Profile Interface was developed to address this issue. It provides a flexible approach to describe the constraints applied to trajectory generation and may provide a method for interoperability between trajectory generators. It also supports the request and generation of new types of trajectory profiles not possible with the previous interface to the Trajectory Synthesizer. Other enhancements allow the Trajectory Synthesizer to meet the current and future needs of Air Traffic Management research.

  13. Method to synthesize metal chalcogenide monolayer nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Sanchez, Bernadette A.; Boyle, Timothy J.

    2016-12-13

    Metal chalcogenide monolayer nanomaterials can be synthesized from metal alkoxide precursors by solution precipitation or solvothermal processing. The synthesis routes are more scalable, less complex and easier to implement than other synthesis routes.

  14. Fundamentals of fiber lasers and fiber amplifiers

    CERN Document Server

    Ter-Mikirtychev, Valerii (Vartan)

    2014-01-01

    This book covers the fundamental aspects of fiber lasers and fiber amplifiers, and includes a wide range of material from laser physics fundamentals to state-of-the-art topics in this rapidly growing field of quantum electronics. Emphasis is placed on the nonlinear processes taking place in fiber lasers and amplifiers, their similarities, differences to, and their advantages over other solid-state lasers. The reader will learn basic principles of solid-state physics and optical spectroscopy of laser active centers in fibers, main operational laser regimes, and practical recommendations and suggestions on fiber laser research, laser applications, and laser product development. The book will be useful for students, researchers, and professionals who work with lasers, in the optical communications, chemical and biological industries, etc.

  15. New Mixer Used in Direct Frequency Synthesizer

    Directory of Open Access Journals (Sweden)

    Milan Stork

    2008-01-01

    Full Text Available Frequency synthesizers are an essential part of any modern transceiver system. They generate clock and oscillator signals needed for up and down conversion. Today’s communication standards demand both high frequency accuracy and fast frequency settling. The fine frequency resolution, low spurious signals, accuracy and stability are most important for these devices. In this paper, the new frequency synthesizer architecture based on direct synthesis and coincidence mixer is presented. The simulation results are also shown.

  16. Raman assisted lightwave synthesized frequency sweeper

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2010-01-01

    We present a Lightwave Synthesized Frequency Sweeper comprising a Raman amplifier for loss compensation. The generated pulse train contains 123 pulses and has a flat signal level as well as a low noise level.......We present a Lightwave Synthesized Frequency Sweeper comprising a Raman amplifier for loss compensation. The generated pulse train contains 123 pulses and has a flat signal level as well as a low noise level....

  17. Oil sorption by lignocellulosic fibers

    Science.gov (United States)

    Beom-Goo. Lee; James S. Han; Roger M. Rowell

    1999-01-01

    The oil sorption capacities of cotton fiber, kenaf bast fiber, kenaf core fiber, and moss fiber were compared after refining, extraction, and reduction in particle sizes. The tests were conducted on diesel oil in a pure form. Cotton fiber showed the highest capacity, followed by kenaf core and bast fibers. Wetting, extraction, and reduction in particle size all...

  18. Whole Grains and Fiber

    Science.gov (United States)

    ... whole grains. Does not contain partially hydrogenated oils. Dietary Fiber Dietary fiber is the term for several materials that make ... water. When eaten regularly as part of a diet low in saturated fat and trans fat soluble fiber has been associated with increased diet quality and ...

  19. Resonant filtered fiber amplifiers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Laurila, Marko; Olausson, Christina Bjarnal Thulin

    2013-01-01

    In this paper we present our recent result on utilizing resonant/bandgap fiber designs to achieve high performance ytterbium doped fiber amplifers for achieving diffraction limited beam quality in large mode area fibers, robust bending performance and gain shaping for long wavelength operation of...

  20. Mineral Fiber Toxicology

    Science.gov (United States)

    The chemical and physical properties of different forms of mineral fibers impact biopersistence and pathology in the lung. Fiber chemistry, length, aspect ratio, surface area and dose are critical factors determining mineral fiber-associated health effects including cancer and as...

  1. The Fiber Optic Connection.

    Science.gov (United States)

    Reese, Susan

    2003-01-01

    Describes the fiber optics programs at the Career and Technical Center in Berlin, Pennsylvania and the Charles S. Monroe Technology Center in Loudoun County, Virginia. Discusses the involvement of the Fiber Optic Association with education, research and development, manufacturing, sales, distribution, installation, and maintenance of fiber optic…

  2. Fiber Nonlinearities: A Tutorial

    Institute of Scientific and Technical Information of China (English)

    Govind P. Agrawal

    2003-01-01

    Fiber nonlinearities have long been regarded as being mostly harmful for fiber-optic communication systems. Over the last few years, however, the nonlinear effects are increasingly being used for practical telecommunications applications,the Raman amplification being only one of the recent examples. In this tutorial I review the vario us nonlinear effects occurring in optical fibers from both standpoints..

  3. Fiber Nonlinearities: A Tutorial

    Institute of Scientific and Technical Information of China (English)

    Govind; P.; Agrawal

    2003-01-01

    Fiber nonlinearities have long been regarded as being mostly harmful for fiber-optic communication systems. Over the last few years, however, the nonlinear effects are increasingly being used for practical telecommunications applications, the Raman amplification being only one of the recent examples. In this tutorial I review the various nonlinear effects occurring in optical fibers from both standpoints..

  4. Microplastics in the Baltic Sea water: fibers everywhere.

    Science.gov (United States)

    Khatmullina, Lilia; Bagaev, Andrey; Chubarenko, Irina

    2017-04-01

    Presence of thin synthetic fibres (microfibres, tens of micrometres in diameter) in the surface waters and sediments is documented in different studies; however, the data on their exact abundances in the marine environment are commonly not presented owing to the shortcomings of the sampling procedure and general absence of well-established methodology for microplastics data collection. Nevertheless, we made an attempt to qualitatively analyse the amounts of microplastic fibres in the water column of the Baltic Sea. Water samples acquired during 6 cruises over the Baltic Sea Proper in 2015-2016 were filtered using 174 μm filters, which were subsequently analysed by microscope. From the total of 95 examined filters, 63% contained fibres. They were identified by colour and the reaction to the mechanical action of a thin needle: justification of anthropogenic origin was considered to be enough; any questionable objects were discarded. Fibres comprise more than 90% of the whole microplastic particles found in the near-bottom layers in the coastal zone and around 24% of microplastics in the surface and intermediate waters, with mean concentrations of 0.71 and 0.07 fibres per litre, respectively. Although the methodology still requires a lot of enhancement, even the preliminary results indicate ubiquitous distribution of the microfibres in the water column of the Baltic Sea with surface and bottom layers revealing higher abundances of microfibres in comparison with intermediate layers, and open-sea waters being less contaminated than the coastal ones. Apart from enhancing the sampling technics, we consider that it is crucial to understand principal physical features of fibers behavior in the marine environment (e.g., settling, entrainment by currents), as it would provide an opportunity to parameterize their transport and further on to model distribution of fibers in the water column. The research is supported by the Russian Science Foundation grant number 15-17-10020.

  5. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    , leading to reduced mode confinement and dispersion flexibility. In this thesis, we treat the nonlinear photonic crystal fiber – a special sub-class of photonic crystal fibers, the core of which has a diameter comparable to the wavelength of the light guided in the fiber. The small core results in a large...... nonlinear coefficient and in various applications, it is therefore possible to reduce the required fiber lengths quite dramatically, leading to increased stability and efficiency. Furthermore, it is possible to design these fibers with zero-dispersion at previously unreachable wavelengths, paving the way...... for completely new applications, especially in and near the visible wavelength region. One such application is supercontinuum generation. Supercontinuum generation is extreme broadening of pulses in a nonlinear medium (in this case a small-core fiber), and depending on the dispersion of the fiber, it is possible...

  6. VCO PLL Frequency Synthesizers for Spacecraft Transponders

    Science.gov (United States)

    Smith, Scott; Mysoor, Narayan; Lux, James; Cook, Brian

    2007-01-01

    Two documents discuss a breadboard version of advanced transponders that, when fully developed, would be installed on future spacecraft to fly in deep space. These transponders will be required to be capable of operation on any deepspace- communications uplink frequency channel between 7,145 and 7,235 MHz, and any downlink frequency channel between 8,400 and 8,500 MHz. The document focuses on the design and operation of frequency synthesizers for the receiver and transmitter. Heretofore, frequency synthesizers in deep-space transponders have been based on dielectric resonator oscillators (DROs), which do not have the wide tuning bandwidth necessary to tune over all channels in the uplink or downlink frequency bands. To satisfy the requirement for tuning bandwidth, the present frequency synthesizers are based on voltage-controlled-oscillator (VCO) phase-locked loops (PLLs) implemented by use of monolithic microwave integrated circuits (MMICs) implemented using inGaP heterojunction bipolar transistor (HBT) technology. MMIC VCO PLL frequency synthesizers similar to the present ones have been used in commercial and military applications but, until now, have exhibited too much phase noise for use in deep-space transponders. The present frequency synthesizers contain advanced MMIC VCOs, which use HBT technology and have lower levels of flicker (1/f) phase noise. When these MMIC VCOs are used with high-speed MMIC frequency dividers, it becomes possible to obtain the required combination of frequency agility and low phase noise.

  7. Synthesizing Modular Invariants for Synchronous Code

    Directory of Open Access Journals (Sweden)

    Pierre-Loic Garoche

    2014-12-01

    Full Text Available In this paper, we explore different techniques to synthesize modular invariants for synchronous code encoded as Horn clauses. Modular invariants are a set of formulas that characterizes the validity of predicates. They are very useful for different aspects of analysis, synthesis, testing and program transformation. We describe two techniques to generate modular invariants for code written in the synchronous dataflow language Lustre. The first technique directly encodes the synchronous code in a modular fashion. While in the second technique, we synthesize modular invariants starting from a monolithic invariant. Both techniques, take advantage of analysis techniques based on property-directed reachability. We also describe a technique to minimize the synthesized invariants.

  8. Preparation and Characterization of M-Type Barium Ferrite Fibers via Aqueous Sol-Gel Process

    Institute of Scientific and Technical Information of China (English)

    GONG Cairong; FAN Guoliang; SONG Chonglin; L(U) Gang

    2007-01-01

    BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe(OH)( HCOO)2 synthesized in laboratory and Ba(CH3COO)2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable sol was characterized on rheometer, and the development of gel fibers to barium ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM, and the diameter of the obtained fibers was between 5 and 10 μm corresponding to different additives. The additives affected the surface tension of the precursor sol which had close relation to the microstructure of fibers. Sucrose and hydroxyethylic cellulose could improve the surface tension while diethanolamine and hexadecylamine reduce that of the precursor sol. And using diethanolamine or hexadecylamine as an additive, well-structured BaFe12O19 fibers could be obtained.

  9. Dielectric behavior of epoxy/BaTiO₃ composites using nanostructured ceramic fibers obtained by electrospinning.

    Science.gov (United States)

    Ávila, H A; Ramajo, L A; Góes, M S; Reboredo, M M; Castro, M S; Parra, R

    2013-02-01

    Composite materials made of epoxy resin and barium titanate (BT) electrospun nanostructured fibers were prepared. BT fibers were synthesized from a sol based on barium acetate, titanium isopropoxide, and poly(vinyl pyrrolidone). The fibers were heat-treated at different temperatures and characterized by X-ray diffraction, scanning electron microscopy (SEM), and Raman spectroscopy. Mats of BT fibers heat-treated at 800 °C were embedded in epoxy resin into suitable molds. The composites were characterized by SEM, and dielectric measurements were performed by means of dielectric spectroscopy. The dielectric permittivity and dielectric modulus of epoxy resin/BT-fiber composites were measured for two types of samples: with the electrodes parallel and perpendicular to the BT fiber layers. Interestingly, composite samples with electrodes perpendicular to the fiber layers and a BT content as low as 2 vol % led to dielectric permittivities three times higher than that of pure epoxy resin.

  10. Optical fiber design with orbital angular momentum light purity higher than 99.9.

    Science.gov (United States)

    Zhang, Zhishen; Gan, Jiulin; Heng, Xiaobo; Wu, Yuqing; Li, Qingyu; Qian, Qi; Chen, Dongdan; Yang, Zhongmin

    2015-11-16

    The purity of the synthesized orbital-angular-momentum (OAM) light in the fiber is inversely proportional to channel crosstalk level in the OAM optical fiber communication system. Here the relationship between the fiber structure and the purity is firstly demonstrated in theory. The graded-index optical fiber is proposed and designed for the OAM light propagation with the purity higher than 99.9%. 16 fiber modes (10 OAM modes) have been supported by a specific designed graded-index optical fiber with dispersion less than 35 ps/(km∙nm). Such fiber design has suppressed the intrinsic crosstalk to be lower than -30 dB, and can be potentially used for the long distance OAM optical communication system.

  11. An automated Teflon microfluidic peptide synthesizer.

    Science.gov (United States)

    Zheng, Hui; Wang, Weizhi; Li, Xiaojun; Wang, Zihua; Hood, Leroy; Lausted, Christopher; Hu, Zhiyuan

    2013-09-07

    We present a microfluidic synthesizer made entirely of Teflon material for solid phase peptide synthesis (SPPS). Solvent-resistant perfluoroalkoxy (PFA) was used to construct chip-sized devices featuring multiple tri-layer pneumatic microvalves. Using these devices, model peptides were automatically synthesized and cleaved in situ in a continuous-flow manner. The total coupling and cleavage time was significantly reduced compared to conventional bulk reactors. The synthesis of a decapeptide, for instance, took less than 6 h using our device while it usually takes more than three days using conventional reactors.

  12. Perception of Paralinguistic Traits in Synthesized Voices

    DEFF Research Database (Denmark)

    Baird, Alice Emily; Hasse Jørgensen, Stina; Parada-Cabaleiro, Emilia

    the paralinguistic traits of the synthesized voice. Using a corpus of 13 synthesized voices, constructed from acoustic concatenative speech synthesis, we assessed the response of 23 listeners from differing cultural backgrounds. Evaluating if the perception shifts from the known ground–truths, we asked listeners...... to assigned traits of age, gender, accent origin, and human–likeness. Results present a difference in perception for age and human–likeness across voices, and a general agreement across listeners for both gender and accent origin. Connections found between age, gender and human–likeness call for further...

  13. Hierarchically Structured Electrospun Fibers

    Directory of Open Access Journals (Sweden)

    Nicole E. Zander

    2013-01-01

    Full Text Available Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

  14. Engineering of silicon-based ceramic fibers: Novel SiTaC(O) ceramic fibers prepared from polytantalosilane

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z., E-mail: xiezhengfang@163.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Cao, S.; Wang, J. [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Yan, X. [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Bernard, S., E-mail: Samuel.Bernard@univ-lyon1.fr [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Miele, P. [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France)

    2010-10-15

    Research highlights: {yields} This paper reports the preparation and characterization of a novel variety of silicon-based ceramic fibers. {yields} In the present paper, we provide a detailed picture of the preparation process of SiTaC(O) ceramic fibers from a polytantalosilane. {yields} We have fully characterized the polymer by FT-IR, NMR, chemical composition, GPC and TGA as well as the chemical composition, the structure, the texture, and the mechanical properties of the ceramic fibers by XPS, SEM, X-ray diffraction (XRD), and mechanical tests. - Abstract: A novel variety of silicon-based ceramic fibers has been prepared from a preceramic organosilicon polymers called polytantalocarbosilane (PTaCS). This melt-spinnable polymer has been synthesized by thermally induced reactions between tantalum (V) tetraethoxyacetylacetonate (Ta(Acac)(OEt){sub 4}) and polysilacarbosilane (PSCS). The polymer in which [-Si-C-]{sub n} chains are crosslinked via Ta-containing bridges as identified by infrared spectroscopy, XPS and NMR, is decomposed in high ceramic yield (76%) and can be spun in the molten state into fibers to be cured in air then pyrolyzed in flowing nitrogen at 1200 deg. C into amorphous SiTaC(O) fibers. Complete characterization of this new generation of silicon-based ceramic fibers was made based on mechanical tests, XRD and SEM. These fibers exhibit relatively good mechanical properties and excellent high-temperature stability with good oxidation resistance.

  15. Preparation and properties of hexagonal boron nitride fibers used as high temperature membrane filter

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xinmei, E-mail: houxinmei@ustb.edu.cn; Yu, Ziyou; Li, Yang; Chou, Kuo-Chih

    2014-01-01

    Graphical abstract: - Highlights: • h-BN fibers were successfully fabricated using H{sub 3}BO{sub 3} and C{sub 3}H{sub 6}N{sub 6} as raw materials. • The obtained BN fibers were polycrystalline and uniform in morphology. • It exhibited good oxidation resistance and low thermal expansion coefficient. - Abstract: Hexagonal boron nitride fibers were synthesized via polymeric precursor method using boric acid (H{sub 3}BO{sub 3}) and melamine (C{sub 3}H{sub 6}N{sub 6}) as raw materials. The precursor fibers were synthesized by water bath and BN fibers were prepared from the precursor at 1873 K for 3 h in flowing nitrogen atmosphere. The crystalline phase and microstructures of BN fibers were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy. The results showed that h-BN fibers with uniform morphology were successfully fabricated. The well-synthesized BN fibers were polycrystalline with 0.4–1.5 μm in diameter and 200–500 μm in length. The as-prepared samples exhibited good oxidation resistance and low thermal expansion coefficient at high temperature.

  16. Fiber Lasers V

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2008-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser...... laser system. We present the latest advancements within airclad fiber technology including a new 70 μm single-mode polarization-maintaining rod-type fiber capable of amplifying to MW power levels. Furthermore we describe the novel airclad based pump combiners and their use in a completely monolithic 350...... W CW fiber laser system with an M2 of less than 1.1. Finally, we briefly touch upon the subject of photo darkening and its origin....

  17. Polymer optical fiber fuse

    CERN Document Server

    Mizuno, Yosuke; Tanaka, Hiroki; Nakamura, Kentaro

    2013-01-01

    Although high-transmission-capacity optical fibers are in demand, the problem of the fiber fuse phenomenon needs to be resolved to prevent the destruction of fibers. As polymer optical fibers become more prevalent, clarifying their fuse properties has become important. Here, we experimentally demonstrate a fuse propagation velocity of 21.9 mm/s, which is 1 to 2 orders of magnitude slower than that in standard silica fibers. The achieved threshold power density and proportionality constant between the propagation velocity and the power density are respectively 1/186 of and 16.8 times the values for silica fibers. An oscillatory continuous curve instead of periodic voids is formed after the passage of the fuse. An easy fuse termination method is presented herein, along with its potential plasma applications.

  18. Airclad fiber laser technology

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2008-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser...... laser system. We present the latest advancements within airclad fiber technology including a new 70 μm single-mode polarization-maintaining rod-type fiber capable of amplifying to MW power levels. Furthermore we describe the novel airclad based pump combiners and their use in a completely monolithic 350...... W CW fiber laser system with an M2 of less than 1.1. Finally, we briefly touch upon the subject of photo darkening and its origin....

  19. Airclad fiber laser technology

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2011-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last 5 years. Many of the traditional manufacturers of gas and solid-state lasers are now pursuing the fiber-based systems, which are displacing the conventional technology in many areas. High-power fiber laser systems...... laser system. We present the latest advancements within airclad fiber technology including a new 100 m single-mode polarization-maintaining rod-type fiber capable of amplifying to megawatt power levels. Furthermore, we describe the novel airclad-based pump combiners and their use in a completely...... monolithic 350 W cw fiber laser system with an M2 of less than 1.1. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE)....

  20. Raman fiber lasers

    Science.gov (United States)

    Supradeepa, V. R.; Feng, Yan; Nicholson, Jeffrey W.

    2017-02-01

    High-power fiber lasers have seen tremendous development in the last decade, with output powers exceeding multiple kilowatts from a single fiber. Ytterbium has been at the forefront as the primary rare-earth-doped gain medium owing to its inherent material advantages. However, for this reason, the lasers are largely confined to the narrow emission wavelength region of ytterbium. Power scaling at other wavelength regions has lagged significantly, and a large number of applications rely upon the diversity of emission wavelengths. Currently, Raman fiber lasers are the only known wavelength agile, scalable, high-power fiber laser technology that can span the wavelength spectrum. In this review, we address the technology of Raman fiber lasers, specifically focused on the most recent developments. We will also discuss several applications of Raman fiber lasers in laser pumping, frequency conversion, optical communications and biology.

  1. Evaluating Text-to-Speech Synthesizers

    Science.gov (United States)

    Cardoso, Walcir; Smith, George; Fuentes, Cesar Garcia

    2015-01-01

    Text-To-Speech (TTS) synthesizers have piqued the interest of researchers for their potential to enhance the L2 acquisition of writing (Kirstein, 2006), vocabulary and reading (Proctor, Dalton, & Grisham, 2007) and pronunciation (Cardoso, Collins, & White, 2012; Soler-Urzua, 2011). Despite their proven effectiveness, there is a need for…

  2. Cytotoxicity of Nanoliposomal Cisplatin Coated with Synthesized ...

    African Journals Online (AJOL)

    The characteristics of the nanoparticles were evaluated by dynamic light ... scanning electron microscopy (SEM). ... that of free cisplatin in human ovarian cancer cell line A2780CP. ... was -20 °C under inert gas stream [12]. The .... Figure 2: SEM image of nanoliposomal cisplatin ... The chemical structure of the synthesized.

  3. Concise total syntheses of (+/-)-strychnine and (+/-)-akuammicine.

    Science.gov (United States)

    Sirasani, Gopal; Paul, Tapas; Dougherty, William; Kassel, Scott; Andrade, Rodrigo B

    2010-05-21

    Concise total syntheses of Strychnos alkaloids strychnine (1) and akuammicine (2) have been realized in 13 and 6 operations, respectively. Key steps include (1) the vinylogous Mannich reaction; (2) a novel, sequential one-pot spirocyclization/intramolecular aza-Baylis-Hillman reaction; and (3) a Heck cyclization. The synthesis of 1 proceeds via the Wieland-Gumlich aldehyde (26).

  4. Method and apparatus for synthesizing filamentary structures

    Energy Technology Data Exchange (ETDEWEB)

    Height, Murray J [Somerville, MA; Howard, Jack B [Winchester, MA; Vandersande, John B [Newbury, MA

    2008-02-26

    Method and apparatus for producing filamentary structures. The structures include single-walled nanotubes. The method includes combusting hydrocarbon fuel and oxygen to establish a non-sooting flame and providing an unsupported catalyst to synthesize the filamentary structure in a post-flame region of the flame. Residence time is selected to favor filamentary structure growth.

  5. Urea Decomposition Method to Synthesize Hydrotalcites

    Institute of Scientific and Technical Information of China (English)

    Piao Ping YANG; Jian Feng YU; Tong Hao WU; Guo Zong LIU; Tae Sun CHANG; Dong Koo LEE; Deug Hee CHO

    2004-01-01

    The urea decomposition property at high temperature has been used to control the pH value in the synthesis of layer compounds. The hydrotalcites of Mg-Al and Ni-Al with high crystallinity were synthesized by using this property.

  6. Digital Frequency Synthesizer For Radar Astronomy

    Science.gov (United States)

    Sadr, Ramin; Satorius, Edgar; Robinett, J. Loris, Jr.; Olson, Erlend

    1992-01-01

    Report discusses conceptual digital frequency synthesizer part of programmable local oscillator in radar-astronomy system. Phase must remain continuous during adjustments of frequency, phase noise must be low, and spectral purity must be high. Discusses theory of operation in some mathematical detail and presents new analysis of spectral purity of output.

  7. Synthesizing Waves from Animated Height Fields

    DEFF Research Database (Denmark)

    Nielsen, Michael Bang; Söderström, Andreas; Bridson, Robert

    2013-01-01

    for synthesizing Fourier-based ocean waves that match a previs input, allowing artists to quickly enhance the input wave animation with additional higher-frequency detail that moves consistently with the coarse waves, tweak the wave shapes to flatten troughs and sharpen peaks if desired (as is characteristic...

  8. Syntheses of very dense halogenated liquids.

    Science.gov (United States)

    Ye, Chengfeng; Shreeve, Jean'ne M

    2004-09-17

    A family of halogenated liquids with densities ranging from 1.95 to 2.80 g cm(-3) was readily synthesized by a one-pot procedure. These liquids exhibit characteristics of ionic liquids with melting/transition points lower than room temperature, long liquid ranges, and marked hydrolytic and thermal stabilities.

  9. Nanotailored Carbon Fibers

    Science.gov (United States)

    2012-04-27

    precursor fiber and also utilize bi- component spinning along with gel spinning, to obtain small diameter fibers. Various processing parameters during...shape of the fiber. In this regard, we have also conducted single component gel spinning using different gelation bath temperatures (100% methanol). SEM...domestic dishwashing detergent, Palmolive antibacterial , 3 wt% detergent and 97% water) for about a week and retested. *** For 5th trial, tungsten

  10. Continuous Fiber Ceramic Composites

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  11. Insulated Fiber Brush.

    Science.gov (United States)

    An insulated-strand fiber brush is provided for a DC motor /generator. The brush is comprised of a plurality of fiber segments which are insulated from one another near the contact surface of a rotor bar. In one embodiment, insulating spacers are fixed to a brush assembly and wear with the fibers, and in another embodiment insulation is provided by a separate shell. (Author)

  12. SILICA SURFACED CARBON FIBERS.

    Science.gov (United States)

    carbon fibers . Several economical and simple processes were developed for obtaining research quantities of silica surfaced carbon filaments. Vat dipping processes were utilized to deposit an oxide such as silica onto the surface and into the micropores of available carbon or graphite base fibers. High performance composite materials were prepared with the surface treated carbon fibers and various resin matrices. The ablative characteristics of these composites were very promising and exhibited fewer limitations than either silica or...treated

  13. Preparation of CeO(2)-ZrO(2) ceramic fibers by electrospinning.

    Science.gov (United States)

    Zhang, Yanfei; Li, Jiayan; Li, Qin; Zhu, Ling; Liu, Xiangdong; Zhong, Xinghua; Meng, Jian; Cao, Xueqiang

    2007-03-15

    Electrospinning was employed to fabricate polymer-ceramic composite fibers from solutions containing poly(vinyl pyrrolidone) (PVP), Ce(NO(3))(3) x 6H(2)O and ZrOCl(2) x 8H(2)O. Upon firing the composite fibers at 1000 degrees C, Ce(0.67)Zr(0.33)O(2) fibers with diameters ranging from 0.4 to 2 microm were synthesized. These fibers exhibit strong resistance to sintering. They still have specific surface area around 11.8 m(2)/g after being heated at 1000 degrees C for 6 h.

  14. Controlled Synthesis of Dendritic Polyaniline Fibers with Diameters from Nanosize to Submicrometersize

    Institute of Scientific and Technical Information of China (English)

    Xiao Cong WANG; Shu Jiang DING; Jing CAO; Fa Lun WU; Chen ZHOU; Zhen Zhong YANG

    2005-01-01

    Dendritic polyaniline nanofibers and submicrometer-sized fibers have been synthesized by chemical oxidative polymerization of aniline (An) doped with salicylic acid (SA). The diameters of the fibers could be controlled easily from 30 to 400 nm by varying the concentration of aniline and salicylic acid at room temperature. Scanning electron microscopy (SEM) and typical transmission electron microscopy (TEM) were applied to investigate their morphologies. Fourier transform infrared (FTIR) spectrum indicated that the state of the dendritic polyaniline fibers is emerialdine rather than solely the leucoemeraldine or permigraniline forms. The dendritic polyaniline fibers have potential applications as chemical sensors or actuators and neuron devices.

  15. Fabrication of continuous fiber-reinforced ceramics with a nanosized mullite precursor

    Energy Technology Data Exchange (ETDEWEB)

    Reese, O.; Saruhan, B.; Kanka, B.; Schneider, H. [Institute of Materials Research, Cologne (Germany)

    1995-12-01

    Chemically synthesized mullite precursor powders which are suitable materials for the production of continuous fiber-reinforced mullite composites, owing to their high sintering activity at relatively low processing temperatures were used as a matrix material. Since commercially available polycrystalline mullite fibers become instable at high temperatures, optimized slip-casting and sintering conditions were used which allowed hot-pressing of the composites at temperatures lower than 1250{degrees}C. A strong interfacial bonding between fiber and matrix has been observed due to the preferential grain growth which starts on the fiber surfaces and extends into the matrix.

  16. Agave Americana Leaf Fibers

    Directory of Open Access Journals (Sweden)

    Ashish Hulle

    2015-02-01

    Full Text Available The growing environmental problems, the problem of waste disposal and the depletion of non-renewable resources have stimulated the use of green materials compatible with the environment to reduce environmental impacts. Therefore, there is a need to design products by using natural resources. Natural fibers seem to be a good alternative since they are abundantly available and there are a number of possibilities to use all the components of a fiber-yielding crop; one such fiber-yielding plant is Agave Americana. The leaves of this plant yield fibers and all the parts of this plant can be utilized in many applications. The “zero-waste” utilization of the plant would enable its production and processing to be translated into a viable and sustainable industry. Agave Americana fibers are characterized by low density, high tenacity and high moisture absorbency in comparison with other leaf fibers. These fibers are long and biodegradable. Therefore, we can look this fiber as a sustainable resource for manufacturing and technical applications. Detailed discussion is carried out on extraction, characterization and applications of Agave Americana fiber in this paper.

  17. Oriented Fiber Filter Media

    Directory of Open Access Journals (Sweden)

    R. Bharadwaj

    2008-06-01

    Full Text Available Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a thick layered media can improve performance by about 40%. The results also show the improved performance is not monotonically correlated to the average fiber angle of the medium.

  18. PULP FIBER SIZE CHARACTERIZATION

    Institute of Scientific and Technical Information of China (English)

    ShijieLiu

    2004-01-01

    Pulp fiber length distribution characterization hasbeen examined in this study. Because of the fibermorphology: slender in shape, fiber size distributioncharacterization is a very difficult task. Traditionaltechnique involves separation of the particles by size,such as Bauer-McNett fiber classifier, and measuringthe weight fractions. Themay or may not reflect theparticle fractions obtaineddesired size classification.On the other hand, the more recent technique throughoptical measurement of fiber length is limited by itsinability to measure the mass of the particle fractions.Therefore, not only the two techniques fail togenerate identical results, either one was accepted tobe of better value. Pure hardwood kraft, softwoodkraft, and their mixture samples have been measuredfor their fiber length distributions using an opticalfiber quality analyzer: FQA. The data obtained fromFQA are extensively studied to investigate morereliable way of representing the fiber length data andthus examining the viable route for measuring thefiber size distributions. It has been found that thefiber length averaged length 1~ is a viable indicator ofthe average pulp fiber length. The fiber size fractionand/or distribution can be represented by the fiber"length" fractions.

  19. ZBLAN, Silica Fiber Comparison

    Science.gov (United States)

    1998-01-01

    This graph depicts the increased signal quality possible with optical fibers made from ZBLAN, a family of heavy-metal fluoride glasses (fluorine combined zirconium, barium, lanthanum, aluminum, and sodium) as compared to silica fibers. NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. In the graph, a line closer to the black theoretical maximum line is better. Photo credit: NASA/Marshall Space Flight Center

  20. Applications of monolithic fiber interferometers and actively controlled fibers

    OpenAIRE

    Rugeland, Patrik

    2013-01-01

    The objective of this thesis was to develop applications of monolithic fiber devices and actively controlled fibers. A special twin-core fiber known as a ‘Gemini’ fiber was used to construct equal arm-length fiber interferometers, impervious to temperature and mechanical perturbations. A broadband add/drop multiplexer was constructed by inscribing fiber Bragg gratings in the arms of a Gemini Mach-Zehnder interferometer. A broadband interferometric nanosecond switch was constructed from a micr...

  1. Carbon nanofibers synthesized by pyrolysis of chloroform and ethanol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wang-Hua [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Li, Yuan-Yao, E-mail: chmyyl@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China)

    2015-08-01

    Platelet graphite nanofibers (PGNFs) and turbostratic carbon nanofibers (TSCNFs) were synthesized by the pyrolysis of 3 and 10 vol% chloroform in ethanol, respectively, in the presence of Ni catalyst at 700 °C. Auger electron spectrometry analysis reveals that the participation of chloroform in the synthesis led to Ni–Cl bonding on the surface of the catalysts, resulting in a relatively poor crystalline layer and a coarse surface. Furthermore, the Ni–Cl compound affected the melting point and mobility of Ni, changing the morphology and geometrical shape of Ni particles. A low amount of chlorine in the catalyst led to the formation of smaller catalyst particles with a flat surface, resulting in graphene nanosheets stacked perpendicular to the fiber axis, which became PGNFs. In contrast, a high amount of chlorine in the catalyst led to the aggregation of the catalyst and thus the formation of large catalyst particles with a rough surface, resulting in the random stacking of graphene nanosheets, which became TSCNFs. The participation of chlorine was found to be important in the synthesis of the PGNFs and TSCNFs. - Graphical abstract: Display Omitted - Highlights: • The morphology of CNFs changed while different amount of CHCl{sub 3} presented. • The interaction of Ni and Cl changed the geometry and morphology of catalysts. • The structure of CNFs formed attributed to the surface morphology of catalysts. • PGNFs and TSCNFs were perpendicular and random stacking of graphene.

  2. Optimization of Electrical Methods for Sub -surface Monitoring of Biological Contamination: From Micro-scale to Macroscopic one through Sub-micrometric Topographic and Electrochemical Studies of Oxydation/Reduction Processes Provoked by Bacteria

    Science.gov (United States)

    Dhahri, S.; Marliere, C.

    2012-12-01

    The presence of biological matter (bacteria) in deep geological sites for storage of, for instance, radioactive elements or groundwater in aquifers was clearly proved. That biomass triggers physical and chemical processes which greatly modify the durability and the sustainability of the storage sites. These processes, mainly from oxidative/reductive reactions, are poorly understood. This is mainly due to the fact that former studies were done at the macroscopic level far away from the micrometric scale where relevant processes induced by bacteria take place. Investigations at microscopic level are needed. Thus, we developed an experimental set -up based on the combined use of optical microscopy (epifluorescence and transmission), atomic force microscopy (AFM) and scanning electro -chemical microscopy (SECM) in order to get simultaneous information on topographic and electro -chemical processes at different length scales. The first highly sensitive step was to use AFM and optical microscopy with biological samples in liquid environment: We will present a new, non -perturbative method for imaging bacteria in their natural liquid environment using AFM. No immobilization protocol, neither chemical nor mechanical, is needed, contrary to what has been regarded till now as essential. Furthermore we were able to follow the natural gliding movements of bacteria, directly proving their living state during the AFM investigation: we thus directly prove the low impact of these breakthrough AFM observations on the native behavior of the bacteria. The second delicate step was to combine AFM and optical measurements with electrical ones. We mounted a new experimental set-up coupling real -time (i) monitoring of optical properties as the optical density (OD) evolution related to bulk bacterial growth in liquid or as the counting of number of bacteria adhering on the surface of the sample as well and (ii) electrical and electrochemical measurements. We thus will present results on

  3. Soluble and insoluble fiber (image)

    Science.gov (United States)

    Dietary fiber is the part of food that is not affected by the digestive process in the body. ... of the stool. There are two types of dietary fiber, soluble and insoluble. Soluble fiber retains water and ...

  4. A Novel Polarization Maintaining Fiber

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It introduces a novel elliptical jacket polarization maintaining fiber, whose SAP is like numeral "1". One preform can be drawn over 8km. Fiber's performances show that it is fit for fiber gyroscope and other sensors.

  5. A Novel Polarization Maintaining Fiber

    Institute of Scientific and Technical Information of China (English)

    Benjamin Xue

    2003-01-01

    It introduces a novel elliptical jacket polarization maintaining fiber, whose SAP is like numeral "1" One preform can be drawn over 8km. Fiber's performances show that it is fit for fiber gyroscope and other sensors.

  6. Characteristics of Angora rabbit fiber using optical fiber diameter analyzer.

    Science.gov (United States)

    Rafat, S A; de Rochambeau, H; Brims, M; Thébault, R G; Deretz, S; Bonnet, M; Allain, D

    2007-11-01

    An experiment was conducted to describe the characteristics of Angora rabbit fiber using optical fiber diameter analyzer (OFDA). A total of 349 fleece samples were collected from 60 French Angora rabbits. Recorded measurements of OFDA were as follows: mean fiber diameter, CV of fiber diameter, comfort factor, spinning fineness, mean fiber curvature, SD of fiber curvature, mean opacity of fibers, percentage of medullated fibers, mean fiber diameter along the length, and SD of fiber diameter along the length. Comfort factor is the percentage of fibers less than or equal to 30 microns. The main effects included in the mixed model were fixed effects of group, harvest season, and age and a random effect of animal. Correlations among total fleece weight, compression, and OFDA measurements were calculated. Mean fiber diameter was lower than the fiber diameter along the length. Mean percentage of medullated fibers was very low and ranged from 0.1 to 7.3%. The mean comfort factor was 97.5% and ranged from 93.3 to 99.8%. The mean fiber curvature was 40.1 degrees/mm. The major changes in Angora fleece characteristics from 8 to 105 wk of age were an increase in fiber diameter, CV of fiber diameter, mean fiber diameter along the length and curvature, and a decrease in compression and comfort factor. The effect of harvest season was significant on some fiber characteristics. Mean fiber diameter and the mean fiber diameter along the length had a positive correlation with total fleece weight. The OFDA methodology is a method to evaluate fiber diameter, CV of fiber diameter, and bristle content through measuring of the comfort factor. However, OFDA is not adapted for measuring opacity or size of the medulla, or both, in Angora wool and needs a new definition or a special calibration. The spinning fineness should be redefined and adapted for Angora rabbits.

  7. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2008-01-01

    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  8. Carbothermal synthesis of coatings on silicon carbide fibers

    Science.gov (United States)

    Chen, Linlin

    Four kinds of protective coatings---carbide derived carbon (CDC), boron nitride (BN), Al-O-N and BN doped Al-O-N (BAN) have been successfully synthesized on the surface of SiC fibers on the target to enhance the mechanical properties and oxidation resistance of the coated SiC fibers for the application as the reinforcements in the Ceramic Matrix Composites (CMCs) in the high temperatures. First of all, CDC coatings have been uniformly produced on Tyranno ZMI SiC fibers with good thickness control within nanometer accuracy by the chlorination in the temperature range of 550--700°C at atmospheric pressure. Kinetics of the carbon coating growth on the fibers has been systematically studied and thus a good foundation was set up for the further coating synthesis. BN coatings have been synthesized on the surface of SiC powders, fibers and fabrics by a novel carbothermal nitridation method. Non-bridging has been achieved in the BN-coated fiber tows by the nitridation in ammonia at atmospheric pressure in a temperature below 1200°C, which is lower compared to the traditional BN synthesis method and does not cause the degradation of the coated-fibers. BN coatings on the carbon nanotubes have also been formed and unlike the common methods, no additional dopant (such as metal catalyst) is introduced into the system during the BN coatings syntheses, thus the contamination of the final product is avoided. A novel Al-O-N coating has been explored with the most impressive point is that a more than 65% improvement in the tensile strength (up to ˜5.1GPa) and a three-time increase in the Weibull modulus compared to the as-received fibers are resulted by the formation of 200nm Al-O-N coating on the SiC fibers. It exceeds the strength of all other small diameter SiC fibers reported in the literature. Furthermore, BAN coating has also been produced on the surface of SiC fibers and about 20% enhancement in mechanical strength is achieved compared to that of the original fibers

  9. Syntheses and studies of organosilicon compounds

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ren [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    The syntheses of polycarbosilanes and polysilanes as silicon carbide ceramic precursors have been active research areas in the Barton Research Group. In this thesis, the work is focused on the preparation of polycarbosilanes and polysilanes as stoichiometric silicon carbide precursor polymers. The syntheses of the precursor polymers are discussed and the conversions of these precursors to silicon carbide via pyrolysis are reported. The XRD pattern and elemental analyses of the resulting silicon carbide ceramics are presented. Silicon monoxide is an important intermediate in the production of silicon metal. The existence of silicon monoxide in gap phase has been widely accepted. In the second part of this thesis, the generation of gaseous silicon monoxide in four different reactors and the reactions of gaseous silicon monoxide towards organic compounds are discussed.

  10. Processes and applications of silicon carbide nanocomposite fibers

    Science.gov (United States)

    Shin, D. G.; Cho, K. Y.; Jin, E. J.; Riu, D. H.

    2011-10-01

    Various types of SiC such as nanowires, thin films, foam, and continuous fibers have been developed since the early 1980s, and their applications have been expanded into several new applications, such as for gas-fueled radiation heater, diesel particulate filter (DPF), ceramic fiber separators and catalyst/catalyst supports include for the military, aerospace, automobile and electronics industries. For these new applications, high specific surface area is demanded and it has been tried by reducing the diameter of SiC fiber. Furthermore, functional nanocomposites show potentials in various harsh environmental applications. In this study, silicon carbide fiber was prepared through electrospinning of the polycarbosilane (PCS) with optimum molecular weight distribution which was synthesized by new method adopting solid acid catalyst such as ZSM-5 and γ-Al2O3. Functional elements such as aluminum, titanium, tungsten and palladium easily doped in the precursor fiber and remained in the SiC fiber after pyrolysis. The uniform SiC fibers were produced at the condition of spinning voltage over 20 kV from the PCS solution as the concentration of 1.3 g/ml in DMF/Toluene (3:7) and pyrolysis at 1200°C. Pyrolyzed products were processed into several interesting applications such as thermal batteries, hydrogen sensors and gas filters.

  11. Processes and applications of silicon carbide nanocomposite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Shin, D G; Cho, K Y; Riu, D H [Nanomaterials Team, Korea Institute of Ceramic Engineering and Technology, 233-5 Gasan-dong, Guemcheon-gu, Seoul 153-801 (Korea, Republic of); Jin, E J, E-mail: dhriu15@seoultech.ac.kr [Battelle-Korea Laborotary, Korea University, Anamdong, Seongbuk-gu, Seoul (Korea, Republic of)

    2011-10-29

    Various types of SiC such as nanowires, thin films, foam, and continuous fibers have been developed since the early 1980s, and their applications have been expanded into several new applications, such as for gas-fueled radiation heater, diesel particulate filter (DPF), ceramic fiber separators and catalyst/catalyst supports include for the military, aerospace, automobile and electronics industries. For these new applications, high specific surface area is demanded and it has been tried by reducing the diameter of SiC fiber. Furthermore, functional nanocomposites show potentials in various harsh environmental applications. In this study, silicon carbide fiber was prepared through electrospinning of the polycarbosilane (PCS) with optimum molecular weight distribution which was synthesized by new method adopting solid acid catalyst such as ZSM-5 and {gamma}-Al{sub 2}O{sub 3}. Functional elements such as aluminum, titanium, tungsten and palladium easily doped in the precursor fiber and remained in the SiC fiber after pyrolysis. The uniform SiC fibers were produced at the condition of spinning voltage over 20 kV from the PCS solution as the concentration of 1.3 g/ml in DMF/Toluene (3:7) and pyrolysis at 1200deg. C. Pyrolyzed products were processed into several interesting applications such as thermal batteries, hydrogen sensors and gas filters.

  12. Development of shape memory polyurethane fiber with complete shape recoverability

    Science.gov (United States)

    Zhu, Yong; Hu, Jinlian; Yeung, Lap-Yan; Liu, Yan; Ji, Fenglong; Yeung, Kwok-wing

    2006-10-01

    To illustrate the shape memory properties of shape memory polyurethane (SMPU) fiber and the difference of thermal/mechanical properties between SMPU fiber and other various man-made fibers, series of shape memory polyurethane having various hard segment content were synthesized with the pre-polymerization method and spun with the wet spinning process. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical testing were conducted to study the particular thermal/mechanical properties of shape memory polyurethane fiber in comparison with other man-made fibers such as nylon6, polyester, Lycra and XLA. In addition, in the preparation of shape memory polyurethane fiber, the effect of thermal setting temperature was systematically investigated by mechanical properties testing, DMA and cyclic tensile testing, suggesting that the thermal setting temperature has a huge influence on the mechanical properties and shape memory property due to the elimination of internal stress. Thermal setting with a higher temperature will give rise to a lower tensile modulus and tenacity and a higher elongation ratio at break. Through employing the optimal thermal setting treatment, the complete heating responsive recovery in SMPU fiber can be achieved because of the counteracting effect of the irreversible strain and thermal shrinkage.

  13. RF Fiber Optic Link.

    Science.gov (United States)

    1984-06-01

    CONTENTS (Continued) 0 o p- Paragraph Title Page 4.6.3 Laser Diode and Single Mode Fiber Interface ....... 68 0 4.6.4 Laser Noise Discussion...A111-4. 2. 0. Marcuse and C. L. Lin, "Low Dispersion Single-Mode Fiber Transmission - The Question of Practical Versus Theoretical Maxlimum...001/0161A 68 ,.-. .- ,-... -. ..- , .. -............. . ............... • :q

  14. Diskretfrequente Synthese von Nachhall-Prozessen

    OpenAIRE

    Boesnecker, Robert

    2008-01-01

    Die Arbeit verfolgt einen neuartigen Ansatz zur digitalen Nachhallsynthese. Es wird dabei von folgender Beobachtung ausgegangen: Ruft man in ein Klavier, dessen Saiten unbedämpft sind, so antwortet das Instrument mit einem aus diskreten Einzeltönen bestehenden Nachklang, der ähnlich wie ein raumakustischer Nachhall klingt. Verbreitert man bei einer diskretfrequenten Synthese nun die spektrale Breite eines jeden "Klaviertons" auf einen schmalbandigen Bandpass, so dass nicht 12 Töne, sondern 12...

  15. SYNTHESES AND CHARACTERIZATIONS OF HYPERBRANCHED POLYPHENYLENES

    Institute of Scientific and Technical Information of China (English)

    Han Peng; Hong-chen Dong; Yu-ping Dong; De-min Jia; Ben-zhong Tang

    2004-01-01

    New hyperbranched polyphenylenes with high molecular weights are synthesized by the copolycyclotrimerizations of 1,4-diethynylbenzene (I) with phenylacetylene (A), 1-octyne (B), and 1-dodecyne (C) catalyzed by TaCl5-Ph4Sn. The polymers are completely soluble in common solvents such as toluene, THF, chloroform, and dichloromethane. The polymers are characterized by spectroscopic methods and all of the polymers give satisfactory analysis data corresponding to their expected molecular structures.

  16. Predictions of synthesizing element 119 and 120

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The evaporation residue cross sections of synthesizing superheavy nuclei Z=119, 120 are calculated by different sets of master equations with different dynamical variables. Two methods basically predicted similar results that the Ca induced hot fusion can 48 produce element 119 easier than produce 120, and the evaporation residue cross sections for 119 are detectable by current advanced techniques, while the evaporation residue cross sections are below 0.1 pb for producing element 120.

  17. Magnesioferrite synthesized from magnesian-magnetites

    Directory of Open Access Journals (Sweden)

    Marcelo Hidemassa Anami

    2014-02-01

    Full Text Available Magnesioferrite is an important mineral due to its use in different scientific fields and by the fact that the soil through the action of weathering, can be a source of nutrients essential for plant development by the fact that in the soil. Its use in pure form or associated with other minerals is only possible through the synthesis in laboratory conditions. This study aimed to synthesize magnesioferrite and hematite from magnesian-magnetite by a co-precipitation procedure. The methodology used is an adaptation of the method of synthesis of pure magnetite, partially replacing the soluble salts of iron with soluble magnesium salts in the proportion of 30.0 mol% of Fe for Mg. The characterization of the synthetic minerals used x-rays diffraction, total chemical analysis and mass specific magnetic susceptibility. The results showed that besides the magnesian-magnetite an unprecedented muskoxita was synthesized, which upon annealing was converted to magnesioferrite and hematite and in the proportion of 93.1% and 6.9% respectively. The isomorphous substitution of Fe for Mg enhanced the thermal stability of the ferrimagnetic mineral synthesized.

  18. Titanat aluminium synthesized in a solar furnace

    Energy Technology Data Exchange (ETDEWEB)

    Suleimanov, S.; Gulamova, D. [Uzbek Academy of Sciences, Tashkent (Uzbekistan). Materials Science Inst.; Boehmer, M.; Fend, T.; Rietbrock, P. [DLR, Koeln (Germany). MD-ET

    1997-12-31

    Solar furnace technology is an ecologically clean and economically attractive way, most suitable for research and development of new advanced materials. Such features of the solar furnace as sterile conditions of heating, high speed temperature delivering, materials processing in the whole range of the solar spectrum, quenching of the melt with rates of {proportional_to}10{sup 6} K/s, possibility of melting in the cold crucible etc. allow to synthesize complex oxide compositions, such as Al{sub 2}TiO{sub 5}. The study of Al{sub 2}TiO{sub 5} synthesized in the solar furnace has shown that the material is pure {beta}-Al{sub 2}TiO{sub 5} and possesses orthorhombic crystal structure. Microstructure of the material obtained from the melt has a prolonged prismatic shape. When the material is obtained by quenching the microstructure displays fine-grain structure with crystallites of 3-5 micron in size. Raman spectroscopy investigations have been performed on {beta}-Al{sub 2}TiO{sub 5} synthesized on the solar furnace. It has been observed a distinct band at 900 1/cm which is not presented in other six coordinated titanates. Most probably this band is connected with valent vibrations of the Al-O coupling in distorted octahedrons [AlO{sub 6}]. (orig.)

  19. Syntheses and studies of acetylenic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Yiwei, Ding

    1994-03-03

    Based on new diiodo aryl compounds a series of novel soluble polymers, poly(2,5-dialkoxy-1,4-phenyleneethynylene)s (PPE polymers) were synthesized using palladium-catalysis. The molecular weights (MW) range from 8,000 to 40,000. Properties such as absorption, fluorescence, and conductivity were studied. A PPE polymer with butoxy side chain exhibits a weak electrical conductivity ({sigma} = 10{sup {minus}3} S/cm) after doping with AsF{sub 5}. Absorption spectra in THF solution at room temperature (RT) show a maximum at 440 nm. However, absorption spectra of PPE polymers in the film state at (RT) show a maximum at 480 nm. PPE polymer-based light emitting diode (LED) devices have been prepared; greenish light from these LED devices can be observed. Poly(ethynylene-p-arylene-ethynylene-silylene)s were synthesized through the same palladium-catalyzed polymerization; MWs are between 6,000 and 82,000. Absorption and fluorescence were studied. Some of these polymers exhibit thermotropic liquid crystalline properties. In addition, nonlinear optical properties were briefly examined. Poly(silylene-ethynylene) homopolymers as well as alternating copolymers were synthesized through a novel palladium-catalyzed polymerization; MWs range from 56 {times} 10{sup 3} to 5.3 {times} 10{sup 3}. Thermal stability of these was also investigated; char yields range from 56 to 83%. One of these polymers exhibits thermotropic liquid crystalline properties.

  20. Syntheses and studies of acetylenic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Yiwei, Ding [Iowa State Univ., Ames, IA (United States)

    1994-03-03

    Based on new diiodo aryl compounds a series of novel soluble polymers, poly(2,5-dialkoxy-1,4-phenyleneethynylene)s (PPE polymers) were synthesized using palladium-catalysis. The molecular weights (MW) range from 8,000 to 40,000. Properties such as absorption, fluorescence, and conductivity were studied. A PPE polymer with butoxy side chain exhibits a weak electrical conductivity (σ = 10-3 S/cm) after doping with AsF5. Absorption spectra in THF solution at room temperature (RT) show a maximum at 440 nm. However, absorption spectra of PPE polymers in the film state at (RT) show a maximum at 480 nm. PPE polymer-based light emitting diode (LED) devices have been prepared; greenish light from these LED devices can be observed. Poly(ethynylene-p-arylene-ethynylene-silylene)s were synthesized through the same palladium-catalyzed polymerization; MWs are between 6,000 and 82,000. Absorption and fluorescence were studied. Some of these polymers exhibit thermotropic liquid crystalline properties. In addition, nonlinear optical properties were briefly examined. Poly(silylene-ethynylene) homopolymers as well as alternating copolymers were synthesized through a novel palladium-catalyzed polymerization; MWs range from 56 x 103 to 5.3 x 103. Thermal stability of these was also investigated; char yields range from 56 to 83%. One of these polymers exhibits thermotropic liquid crystalline properties.

  1. Method of synthesizing cubic system boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Yuzu, S.; Sumiya, H.; Degawa, J.

    1987-10-13

    A method is described for synthetically growing cubic system boron nitride crystals by using boron nitride sources, solvents for dissolving the boron nitride sources, and seed crystals under conditions of ultra-high pressure and high temperature for maintaining the cubic system boron nitride stable. The method comprises the following steps: preparing a synthesizing vessel having at least two chambers, arrayed in order in the synthesizing vessel so as to be heated according to a temperature gradient; placing the solvents having different eutectic temperatures in each chamber with respect to the boron nitride sources according to the temperature gradient; placing the boron nitride source in contact with a portion of each of the solvents heated at a relatively higher temperature and placing at least a seed crystal in a portion of each of the solvents heated at a relatively lower temperature; and growing at least one cubic system boron nitride crystal in each of the solvents in the chambers by heating the synthesizing vessel for establishing the temperature gradient while maintaining conditions of ultra-high pressure and high temperature.

  2. Green insulation: hemp fibers

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2011-09-15

    Indian hemp (Cannabis indica) is known for its psychotropic values and it is banned in most countries. However, industrial hemp (Cannabis sativa) is known for its tough fibers. Several manufactures in Europe including, small niche players, have been marketing hemp insulation products for several years. Hemp is a low environmental impact material. Neither herbicide nor pesticide is used during the growth of hemp. The fibers are extracted in a waste-free and chemical-free mechanical process. Hemp can consume CO2 during its growth. In addition, hemp fiber can be disposed of harmlessly by composting or incineration at the end of its life. Hemp fibers are processed and treated only minimally to resist rot and fungal activity. There is little health risk when producing and installing the insulation, thanks to the absence of toxic additive. Its thermal resistance is comparable to mineral wool. But the development and marketing of hemp fibers may be restricted in North America.

  3. Python fiber optic seal

    Energy Technology Data Exchange (ETDEWEB)

    Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

    1993-08-01

    Sandia National Laboratories has developed a high security fiber optic seal that incorporates tamper resistance features that are not available in commercial fiber optic seals. The Python Seal is a passive fiber optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber optic pattern created when the seal is installed. The fiber optic cable used for the seal loop is produced with tamper resistant features that increase the difficulty of attacking that component of a seal. A Seal Reader has been developed that will record the seal signature and the fingerprint feature of the seal. A Correlator software program then compares seal images to establish a match or mismatch. SNL is also developing a Polaroid reader to permit hard copies of the seal patterns to be obtained directly from the seal.

  4. Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

    2015-08-04

    Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

  5. XPS study of PBO fiber surface modified by incorporation of hydroxyl polar groups in main chains

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Tao; Hu Dayong; Jin Junhong; Yang Shenglin [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Li Guang, E-mail: lig@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Jiang Jianming [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2010-01-15

    Dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO), a modified poly(p-phenylene benzoxazole) (PBO) polymer containing double hydroxyl groups in polymer chains, was synthesized by copolymerization of 4,6-diamino resorcinol dihydrochloride (DAR), purified terephthalic acid (TA) and 2,5-dihydroxyterephthalic acid (DHTA). DHPBO fibers were prepared by dry-jet wet-spinning method. The effects of hydroxyl polar groups on the surface elemental compositions of PBO fiber were investigated by X-ray photoelectron spectroscopy (XPS). The results show that the ratio of oxygen/carbon on the surface of DHPBO fibers is higher than that on the surface of PBO fibers, which indicates the content of polar groups on the surface of DHPBO fiber increase compared with PBO fiber.

  6. Fiber Pulling Apparatus

    Science.gov (United States)

    Workman, Gary L.; Smith, Guy A.; OBrien, Sue; Adcock, Leonard

    1998-01-01

    The fiber optics industry has grown into a multi-billion marketplace that will continue to grow into the 21st century. Optical fiber communications is currently dominated by silica glass technology. Successful efforts to improve upon the low loss transmission characteristics of silica fibers have propelled the technology into the forefront of the communications industry. However, reaching the theoretical transmission capability of silica fiber through improved processing has still left a few application areas in which other fiber systems can provide an influential role due to specific characteristics of high theoretical transmission in the 2 - 3 micron wavelength region. One of the other major materials used for optical fibers is the systems based upon Heavy Metal Fluoride Glass (HMFG). Commercial interest is driven primarily by the potential for low loss repeaterless infrared fibers. An example of the major communications marketplace which would benefit from the long distance repeaterless capability of infrared fibers is the submarine cables which link the continents. When considering commercial interests, optical fiber systems provide a healthy industrial position which continues to expand. Major investments in the systems used for optical fiber communications have continued to increase each year and are predicted to continue well into the next century. Estimates of 8.5% compounded annually are predicted through 1999 for the North American market and 1 1 % worldwide. The growth for the optical fiber cable itself is expected to continue between 44 and 50 per cent of the optical fiber communications budget through 1999. The total budget in 1999 world-wide is expected to be in the neighborhood of $9 billion. Another survey predicts that long haul telecommunications represents 15% of a world-wide fiber optics market in 1998. The actual amount allotted to cable was not specified. However, another market research had predicted that the cable costs alone represents more

  7. Fiber optic spanner

    Science.gov (United States)

    Black, Bryan; Mohanty, Samarendra

    2011-10-01

    Rotation is a fundamental function in nano/biotechnology and is being useful in a host of applications such as pumping of fluid flow in microfluidic channels for transport of micro/nano samples. Further, controlled rotation of single cell or microscopic object is useful for tomographic imaging. Though conventional microscope objective based laser spanners (based on transfer of spin or orbital angular momentum) have been used in the past, they are limited by the short working distance of the microscope objective. Here, we demonstrate development of a fiber optic spanner for rotation of microscopic objects using single-mode fiber optics. Fiber-optic trapping and simultaneous rotation of pin-wheel structure around axis perpendicular to fiber-optic axis was achieved using the fiber optic spanner. By adjusting the laser beam power, rotation speed of the trapped object and thus the microfluidic flow could be controlled. Since this method does not require special optical or structural properties of the sample to be rotated, three-dimensional rotation of a spherical cell could also be controlled. Further, using the fiber optic spanner, array of red blood cells could be assembled and actuated to generate vortex motion. Fiber optical trapping and spinning will enable physical and spectroscopic analysis of microscopic objects in solution and also find potential applications in lab- on-a-chip devices.

  8. Fiber Optic Microphone

    Science.gov (United States)

    Cho, Y. C.; George, Thomas; Norvig, Peter (Technical Monitor)

    1999-01-01

    Research into advanced pressure sensors using fiber-optic technology is aimed at developing compact size microphones. Fiber optic sensors are inherently immune to electromagnetic noise, and are very sensitive, light weight, and highly flexible. In FY 98, NASA researchers successfully designed and assembled a prototype fiber-optic microphone. The sensing technique employed was fiber optic Fabry-Perot interferometry. The sensing head is composed of an optical fiber terminated in a miniature ferrule with a thin, silicon-microfabricated diaphragm mounted on it. The optical fiber is a single mode fiber with a core diameter of 8 micron, with the cleaved end positioned 50 micron from the diaphragm surface. The diaphragm is made up of a 0.2 micron thick silicon nitride membrane whose inner surface is metallized with layers of 30 nm titanium, 30 nm platinum, and 0.2 micron gold for efficient reflection. The active sensing area is approximately 1.5 mm in diameter. The measured differential pressure tolerance of this diaphragm is more than 1 bar, yielding a dynamic range of more than 100 dB.

  9. Thermal Conductivity Measurement of Synthesized Mantle Minerals

    Science.gov (United States)

    Asimow, P. D.; Luo, S.; Mosenfelder, J. L.; Liu, W.; Staneff, G. D.; Ahrens, T. J.; Chen, G.

    2002-12-01

    Direct thermal conductivity (k) measurement of mantle minerals is crucial to constrain the thermal profile of the Earth as well as geodynamic studies of the mantle (e.g., to determine the Rayleigh number). We have embarked on systematic multi-anvil syntheses of dense polycrystalline specimens of mantle phases of adequate size and zero porosity for precise thermal conductivity measurements by the 3ω method (\\textit{Cahill and Pohl, Phys. Rev. B, 1987}) under elevated temperatures (T). Coesite and stishovite (see \\textit{Luo et al., GRL, 2002}) as well as majorite and wadsleyite have been synthesized; ringwoodite and perovskite are scheduled. Preliminary thermal conductivity measurements at ambient pressure on coesite (120 - 300 K, 9.53 Wm-1K-1 at 300 K) are consistent with prior room temperature data (\\textit{Yukutake & Shimada, PEPI, 1978}), while our stishovite data at 300 K appear to be low (1.96 Wm-1K-1). Efforts are being made to extend the measurement to higher temperatures (e.g., above Debye temperature Θ D), thus allowing determination of k(T) relationship (say, k~ T-n); success will depend on the decomposition kinetics of these metastable phases. The pressure dependence of k of these synthesized samples can also be measured (\\textit{e.g., Osako et al., HPMPS-6, 2002; Xu et al., EOS, 2001}). Recent thermal conductivity measurement on LiF and Al2O_3 from shock wave loading (\\textit{Holland & Ahrens, 1998}) is consistent with the modeling on MgO and Al2O_3 (\\textit{Manga & Jeanloz, JGR, 1997}) with classical theories. Thus, k values at modest pressures and T (say, above Θ D) would allow extrapolation of k to appropriate mantle conditions.

  10. High-Energy Optical Parametric Waveform Synthesizer

    OpenAIRE

    Muecke, Oliver D.; Cirmi, G.; Fang, S.; Rossi, G. M.; Chia, Shih-Hsuan; Kärtner, F. X.; Manzoni, C.; Farinello, P.; Cerullo, and G.

    2014-01-01

    We discuss the ongoing development of a phase-stable, multi-mJ 3-channel parametric waveform synthesizer generating a 2-octave-wide spectrum (0.52-2.4μm). After two amplification stages, the combined >125-μJ output supports 1.9-fs waveforms. First preliminary FROG-characterization results of the second-stage outputs demonstrate the feasibility to recompress all three channels simultaneously close to the Fourier limit. Energy scaling to ~2 mJ is achieved after three amplification stages. The f...

  11. Photochromic glass optical fiber

    Science.gov (United States)

    Alvi, Bilal A.; Israr, Amber; Asif, Muhammad; Aamir, Muhammad; Rehan, Muhammad

    2016-02-01

    This paper describes the fabrication and analysis of novel twin cored fiber which contains a transparent and silver halide doped photochromic core in same cladding. The Photochromic core fibers were fabricated in twin cored structure by rode and tube method. The diameter of photochromic core and transparent core is around 15 m. The distance between two cores is 1.5m. The transparent core was used to guide the probe beam and photochromic core was excited by UV source. The interaction of the probe beam with the excited photochromic core showed the photochromic behavior of the fiber.

  12. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind P

    2001-01-01

    The Optical Society of America (OSA) and SPIE - The International Society for Optical Engineering have awarded Govind Agrawal with an honorable mention for the Joseph W. Goodman Book Writing Award for his work on Nonlinear Fiber Optics, 3rd edition.Nonlinear Fiber Optics, 3rd Edition, provides a comprehensive and up-to-date account of the nonlinear phenomena occurring inside optical fibers. It retains most of the material that appeared in the first edition, with the exception of Chapter 6, which is now devoted to the polarization effects relevant for light propagation in optical

  13. QUARTZ FIBER ELECTROSCOPES

    Science.gov (United States)

    Henderson, R.P.

    1957-09-17

    An instrument carried unobtrusively about the person such as in a finger ring to indicate when that person has been exposed to an unusual radiation hazard is described. A metallized quartz fiber is electrically charged to indicate a full scale reading on an etched glass background. The quartz fiber and the scale may be viewed through a magnifying lens for ease of reading. Incident radiation will ionize gaseous particles in the sealed structure thereby allowing the charge to leak off the quartz fiber with its resulting movement across the scale proportionally indicating the radiation exposure.

  14. ZBLAN Fiber Apparatus Tested

    Science.gov (United States)

    1998-01-01

    Dr. Dernis Tucker of NASA's Marshall Space Flight Center examines a miniature furnace to be used in studying the crystallization of ZBLAN optical fibers under low-gravity conditions aboard the NASA KC-135 low-g aircraft. NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. ZBLAN is a heavy-metal fluoride glass that shows exceptional promise for high-throughput communications with infrared lasers. Photo credit: NASA/Marshall Space Flight Center

  15. Birefringent hollow core fibers

    DEFF Research Database (Denmark)

    Roberts, John

    2007-01-01

    Hollow core photonic crystal fiber (HC-PCF), fabricated according to a nominally non-birefringent design, shows a degree of un-controlled birefringence or polarization mode dispersion far in excess of conventional non polarization maintaining fibers. This can degrade the output pulse in many...... and an increased overlap between the polarization modes at the glass interfaces. The interplay between these effects leads to a wavelength for optimum polarization maintenance, lambda(PM), which is detuned from the wavelength of highest birefringence. By a suitable fiber design involving antiresonance of the core...

  16. Birefringent hollow core fibers

    DEFF Research Database (Denmark)

    Roberts, John

    2007-01-01

    Hollow core photonic crystal fiber (HC-PCF), fabricated according to a nominally non-birefringent design, shows a degree of un-controlled birefringence or polarization mode dispersion far in excess of conventional non polarization maintaining fibers. This can degrade the output pulse in many...... and an increased overlap between the polarization modes at the glass interfaces. The interplay between these effects leads to a wavelength for optimum polarization maintenance, lambda(PM), which is detuned from the wavelength of highest birefringence. By a suitable fiber design involving antiresonance of the core...

  17. Random Fiber Laser

    CERN Document Server

    de Matos, Christiano J S; Brito-Silva, Antônio M; Gámez, M A Martinez; Gomes, Anderson S L; de Araújo, Cid B

    2007-01-01

    We investigate the effects of two dimensional confinement on the lasing properties of a classical random laser system operating in the incoherent feedback (diffusive) regime. A suspension of 250nm rutile (TiO2) particles in a Rhodamine 6G solution was inserted into the hollow core of a photonic crystal fiber (PCF) generating the first random fiber laser and a novel quasi-one-dimensional RL geometry. Comparison with similar systems in bulk format shows that the random fiber laser presents an efficiency that is at least two orders of magnitude higher.

  18. Jilin Chemical Fiber Group Launches Its Largest Carbon Fiber Preject

    Institute of Scientific and Technical Information of China (English)

    Flora

    2011-01-01

    China's carbon fiber precursor production line with 5,000 tons of annual output was put into operation in Jilin Chemical Fiber Group on November 18th this year, creating the maximum production capacity currently in China, for which Jilin Chemical Fiber Group become China's largest carbon fiber precursor production base, The smooth operation of the project has laid a solid foundation for promoting China's carbon fiber industry steady, rapid, and healthy development,

  19. Multifunctional carbon nanotube composite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, E. [Instituto de Carboquimica, CSIC, Miguel Luesma Castan, 4, 50018 Zaragoza (Spain); Dalton, A.B. [Department of Physics, University of Surrey, Guildford (United Kingdom); Collins, S.; Kozlov, M.; Razal, J.; Ebron, V.H.; Selvidge, M.; Ferraris, J.P.; Baughman, R.H. [The NanoTech Institute and Department of Chemistry, University of Texas at Dallas, P.O. Box 830688, BE26, Richardson, TX 75083-0688 (United States); Coleman, J.N. [Department of Physics, Trinity College, Dublin 2 (Ireland); Kim, B.G. [Department of Physics, Pusan National University, Pusan 609-735 (Korea)

    2004-10-01

    Continuous carbon nanotube composite fibers having record energy-to-break (toughness) are reported. These fibers have been employed in the fabrication of lightweight fiber supercapacitors, which can be woven or sewn into fabrics and, therefore, be potentially considered as components for electronic textiles. Moreover, these fibers provided remarkable electromechanical actuator capabilities. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  20. High-density multicore fibers

    DEFF Research Database (Denmark)

    Takenaga, K.; Matsuo, S.; Saitoh, K.;

    2016-01-01

    High-density single-mode multicore fibers were designed and fabricated. A heterogeneous 30-core fiber realized a low crosstalk of −55 dB. A quasi-single-mode homogeneous 31-core fiber attained the highest core count as a single-mode multicore fiber....

  1. Machining of fiber reinforced composites

    Science.gov (United States)

    Komanduri, Ranga; Zhang, Bi; Vissa, Chandra M.

    Factors involved in machining of fiber-reinforced composites are reviewed. Consideration is given to properties of composites reinforced with boron filaments, glass fibers, aramid fibers, carbon fibers, and silicon carbide fibers and to polymer (organic) matrix composites, metal matrix composites, and ceramic matrix composites, as well as to the processes used in conventional machining of boron-titanium composites and of composites reinforced by each of these fibers. Particular attention is given to the methods of nonconventional machining, such as laser machining, water jet cutting, electrical discharge machining, and ultrasonic assisted machining. Also discussed are safety precautions which must be taken during machining of fiber-containing composites.

  2. Thermoplastic coating of carbon fibers

    Science.gov (United States)

    Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

    1989-01-01

    A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

  3. Thermoplastic coating of carbon fibers

    Science.gov (United States)

    Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

    1989-01-01

    A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

  4. Fiber bundle phase conjugate mirror

    Science.gov (United States)

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  5. Recent Advances in Chemoenzymatic Peptide Syntheses

    Directory of Open Access Journals (Sweden)

    Kenjiro Yazawa

    2014-09-01

    Full Text Available Chemoenzymatic peptide synthesis is the hydrolase-catalyzed stereoselective formation of peptide bonds. It is a clean and mild procedure, unlike conventional chemical synthesis, which involves complicated and laborious protection-deprotection procedures and harsh reaction conditions. The chemoenzymatic approach has been utilized for several decades because determining the optimal conditions for conventional synthesis is often time-consuming. The synthesis of poly- and oligopeptides comprising various amino acids longer than a dipeptide continues to pose a challenge owing to the lack of knowledge about enzymatic mechanisms and owing to difficulty in optimizing the pH, temperature, and other reaction conditions. These drawbacks limit the applications of the chemoenzymatic approach. Recently, a variety of enzymes and substrates produced using recombinant techniques, substrate mimetics, and optimal reaction conditions (e.g., frozen aqueous media and ionic liquids have broadened the scope of chemoenzymatic peptide syntheses. In this review, we highlight the recent advances in the chemoenzymatic syntheses of various peptides and their use in developing new materials and biomedical applications.

  6. Biogenic synthesized nanoparticles and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Abhijeet, E-mail: abhijeet.singh@jaipur.manipal.edu; Sharma, Madan Mohan [Manipal University Jaipur (India)

    2016-05-06

    In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO{sub 3} via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV–vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

  7. Biogenic synthesized nanoparticles and their applications

    Science.gov (United States)

    Singh, Abhijeet; Sharma, Madan Mohan

    2016-05-01

    In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO3 via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV-vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

  8. Human microglial cells synthesize albumin in brain.

    Directory of Open Access Journals (Sweden)

    Sung-Min Ahn

    Full Text Available Albumin, an abundant plasma protein with multifunctional properties, is mainly synthesized in the liver. Albumin has been implicated in Alzheimer's disease (AD since it can bind to and transport amyloid beta (Abeta, the causative agent of AD; albumin is also a potent inhibitor of Abeta polymerization. Despite evidence of non-hepatic transcription of albumin in many tissues including kidney and pancreas, non-hepatic synthesis of albumin at the protein level has been rarely confirmed. In a pilot phase study of Human Brain Proteome Project, we found evidence that microglial cells in brain may synthesize albumin. Here we report, for the first time, the de novo synthesis of albumin in human microglial cells in brain. Furthermore, we demonstrate that the synthesis and secretion of albumin from microglial cells is enhanced upon microglial activation by Abeta(1-42- or lipopolysaccharide (LPS-treatment. These data indicate that microglial cells may play a beneficial role in AD by secreting albumin that not only inhibits Abeta polymerization but also increases its clearance.

  9. Fiber optics standard dictionary

    CERN Document Server

    Weik, Martin H

    1997-01-01

    Fiber Optics Vocabulary Development In 1979, the National Communications System published Technical InfonnationBulle­ tin TB 79-1, Vocabulary for Fiber Optics and Lightwave Communications, written by this author. Based on a draft prepared by this author, the National Communications System published Federal Standard FED-STD-1037, Glossary of Telecommunications Terms, in 1980 with no fiber optics tenns. In 1981, the first edition of this dictionary was published under the title Fiber Optics and Lightwave Communications Standard Dictionary. In 1982, the then National Bureau of Standards, now the National Institute of Standards and Technology, published NBS Handbook 140, Optical Waveguide Communications Glossary, which was also published by the General Services Admin­ istration as PB82-166257 under the same title. Also in 1982, Dynamic Systems, Inc. , Fiberoptic Sensor Technology Handbook, co-authored and edited by published the this author, with an extensive Fiberoptic Sensors Glossary. In 1989, the handbook w...

  10. Low-fiber diet

    Science.gov (United States)

    ... slow your bowel movements. This helps decrease diarrhea, gas, and bloating. Your doctor may recommend that you follow a low-fiber diet when you have a flare-up of: Irritable bowel syndrome Diverticulitis Crohn disease ...

  11. Fiber optics engineering

    CERN Document Server

    Azadeh, Mohammad

    2009-01-01

    Covering fiber optics from an engineering perspective, this text emphasizes data conversion between electrical and optical domains. Techniques to improve the fidelity of this conversion (from electrical to optical domain, and vice versa) are also covered.

  12. Hollow-Fiber Clinostat

    Science.gov (United States)

    Rhodes, Percy H.; Miller, Teresa Y.; Snyder, Robert S.

    1990-01-01

    Hollow-fiber clinostat, is bioreactor used to study growth and other behavior of cells in simulated microgravity. Cells under study contained in porous hollow fiber immersed in culture medium inside vessel. Bores in hollow fiber allow exchange of gases, nutrients, and metabolic waste products between living cells and external culture media. Hollow fiber lies on axis of vessel, rotated by motor equipped with torque and speed controls. Desired temperature maintained by operating clinostat in standard tissue-culture incubator. Axis of rotation made horizontal or vertical. Designed for use with conventional methods of sterilization and sanitation to prevent contamination of specimen. Also designed for asepsis in assembly, injection of specimen, and exchange of medium.

  13. Fiber Optics: No Illusion.

    Science.gov (United States)

    American School and University, 1983

    1983-01-01

    A campus computer center at Hofstra University (New York) that holds 70 terminals for student use was first a gymnasium, then a language laboratory. Strands of fiber optics are used for the necessary wiring. (MLF)

  14. Preparation of mullite fiber

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.; Wang, B.; Liu, S.; Yan, Y. [Xiamen Univ. (China). Dept. of Chemistry

    1996-06-01

    Transparent mullite fibers have been prepared using aluminum carboxylates (ACs) and tetraethyl orthosilicate (TEOS) as starting materials. The ACs are derived from the catalyzed dissolution of elemental aluminum in a mixture of formic acid and acetic acid. The solubility of aluminum in the acids is influenced by the concentrations of the acids, water, and additives and the preparation temperature. A 1:4:3:24 molar ratio of aluminum, formic acid, acetic acid, and water dissolves the aluminum completely to give a colorless, clear solution suitable for fiber synthesis. The mixture of the ACs and TEOS, in the presence of ethyl alcohol as a mutual solvent at 50--60 C, is concentrated to give a spinnable dope, from which mullite precursor fibers can be drawn. Heat treatment of the precursor at 1,250 C yields crystallized and transparent mullite fibers.

  15. ZBLAN Fiber Comparison

    Science.gov (United States)

    1998-01-01

    Sections of ZBLAN fibers pulled in a conventional 1-g process (left) and in experiments aboard NASA's KC-135 low-gravity aircraft. The rough surface of the 1-g fiber indicates surface defects that would scatter an optical signal and greatly degrade its quality. ZBLAN is part of the family of heavy-metal fluoride glasses (fluorine combined zirconium, barium, lanthanum, aluminum, and sodium). NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. ZBLAN is a heavy-metal fluoride glass that shows exceptional promise for high-throughput communications with infrared lasers. Photo credit: NASA/Marshall Space Flight Center

  16. Roof Polishing of Optical Fibers

    Science.gov (United States)

    Dholakia, A. R.

    1985-01-01

    Bevealed tip gives optimum coupling efficiency. Abrasive tape used to grind tip of optical fiber. Grinding force depends on stiffness of optical fiber. "Roof" shape on end of optical glass fiber increases efficiency which couples laser light. End surface angle of 65 degrees with perpendicular required for optimum coupling. Since fiber and tape are light in weight and compliant, ridge defect-free, and chipping on fiber edge totally eliminated.

  17. Ground Wood Fiber Length Distributions

    OpenAIRE

    Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.

    2014-01-01

    This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...

  18. Radiation Damage of Quartz Fibers

    CERN Document Server

    Hagopian, V

    1999-01-01

    Quartz fibers are used in high energy physics experiments as the active medium in high radiation area calorimetry. Quartz fibers are also used in the transmission of optical signals. Even though quartz does not damage by moderate amounts of irradiation, the clad of the fibers and the protective coating ( buffer) do damage reducing light transmission. Various types of quartz fibers have been irradiated and measured for light transmission. The most radiation hard quartz fibers are those with quartz clad and aluminum buffer.

  19. Neuroanatomic Fiber Orientation Maps (FOMs)

    DEFF Research Database (Denmark)

    Axer, Hubertus; Jantzen, Jan; Grässel, David;

    2002-01-01

    A new neuroanatomic method is described which allows to map the orientation of central nervous fibers in gross histological sections. Polarised light is used to calculate the angle of inclination and direction of the fibers in each pixel. Serial fiber orientation maps (FOMs) can be aligned and 3D...... reconstructed. This volume allows to identify and segment the major fiber tracts. The feasible goal is a human central nervous fiber atlas....

  20. Raman Scattering of Inorganic Fibers

    OpenAIRE

    1985-01-01

    We have examined evolution of Raman spectra of carbon fibers and SiC fibers through structural transformations caused by heat treatment. Raman spectra of the SiC fibers indicate that the fibers consist of amorphous or microcrystalline SiC and graphitic microcrystals. We discuss the correlation between the tensile strength of the fibers and their microscopic structure deduced from the Raman data.

  1. Synthesis of silicon carbide fibers from polycarbosilane by electrospinning method

    Science.gov (United States)

    Yue, Yuan

    Silicon carbide (SiC) is widely used in many fields due to its unique properties. Bulk SiC normally has a flexural strength of 500 -- 550 MPa, a Vickers hardness of ~27 GPa, a Young's modulus of 380 -- 430 GPa, and a thermal conductivity of approximately 120 W/mK. SiC fibers are of great interest since they are the good candidates for reinforcing ceramic matrix composites (CMCs) because of the weavability and high temperature strength of about two to three GPa at about 1000 °C. Silicon carbide fibers have been synthesized from polycarbosilane (PCS) with ~25 μm diameter using the melt-spinning method, followed by the curing and pyrolysis. In order to fabricate SiC fibers with small diameters, electrospinning method has been studied. The electrospinning technique is notable in that the fiber diameters can be controlled over a scale of nanometers to micrometers by controlling the processing parameters. However, there have only been limited studies of synthesis of silicon carbide fibers from polycarbosilane by electrospinning method. Moreover, there is no previous report for tensile strength testing of SiC fibers synthesized by electrospinning. The main objectives of this thesis are to study these problems. In this study, SiC fibers were obtained from polycarbosilane solutions using electrospinning method. In these solutions, dimethylformamide (DMF) and xylene were used as the solvents. The spinnability of the solutions was studied at different polycarbosilane concentrations, as were the ratios between DMF and xylene. The influence of electrospinning parameters such as voltage, flow rate and volume ratio of solvent on fiber diameter were studied. It was found that a minimal DMF content was ii required for the solutions to be spinnable for each PCS concentration. However, DMF content could not exceed 40% of the solvent volume, otherwise PCS could not be dissolved. The fiber diameters increased with increasing flow rate, and slightly decreased with increasing applied

  2. Fiber optic detector

    Energy Technology Data Exchange (ETDEWEB)

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  3. Diode Pumped Fiber Laser

    Science.gov (United States)

    1983-07-01

    numerical aperture is assumed to be small, the fiber modes are taken to be of the LP-type, described for example by Marcuse (Reference 11). In an (x...Fort Washington, PA. 11. D. Marcuse in Theory of Dielectric Optical Waveguides, Quantum Electronics, Principles and Applications, (Academic...10, 2252-2258, October 1971. 17. D. Marcuse , "Gaussian approximation of the fundamental modes of graded- index fibers," J. Opt. Soc. Am., Vol

  4. Fiber optics welder

    Science.gov (United States)

    Higgins, R.W.; Robichaud, R.E.

    A system is described for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45/sup 0/ angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

  5. Production of mullite fibers

    Science.gov (United States)

    Tucker, Dennis S. (Inventor); Sparks, J. Scott (Inventor)

    1991-01-01

    Disclosed here is a process for making mullite fibers wherein a hydrolizable silicon compound and an aluminum compound in the form of a difunctional aluminum chelate are hydrolized to form sols using water and an alcohol with a catalytic amount of hydrochloric acid. The sols are mixed in a molar ratio of aluminum to silicon of 3 to 1 and, under polycondensation conditions, a fibrous gel is formed. From this gel the mullite fibers can be produced.

  6. Hierarchically Structured Electrospun Fibers

    Science.gov (United States)

    2013-01-07

    range of fluorescence could be tuned from yellow-green to blue , making these fibers ideal for micro- and nano-optoelectronic devices [144]. Figure 7...forces. Rapid phase separation of the distorted droplet and energy minimization may lead to the formation of the spider -web-like structure of the fiber...engineering cellularized blood vessels. Biomaterials 2010, 31, 4313–4321. 59. Thorvaldsson, A.; Stenhamre, H.; Gatenholm, P.; Walkenstrom, P

  7. Electrospun amplified fiber optics.

    Science.gov (United States)

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  8. Preparation and characterization of porous carbon material-coated solid-phase microextraction metal fibers.

    Science.gov (United States)

    Zhu, Fang; Guo, Jiaming; Zeng, Feng; Fu, Ruowen; Wu, Dingcai; Luan, Tiangang; Tong, Yexiang; Lu, Tongbu; Ouyang, Gangfeng

    2010-12-10

    Two kinds of porous carbon materials, including carbon aerogels (CAs), wormhole-like mesoporous carbons (WMCs), were synthesized and used as the coatings of solid-phase microextraction (SPME) fibers. By using stainless steel wire as the supporting core, six types of fibers were prepared with sol-gel method, direct coating method and direct coating plus sol-gel method. Headspace SPME experiments indicated that the extraction efficiencies of the CA fibers are better than those of the WMC fibers, although the surface area of WMCs is much higher than that of CAs. The sol-gel-CA fiber (CA-A) exhibited excellent extraction properties for non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene), while direct-coated CA fiber (CA-B) presented the best performance in extracting polar compounds (phenols). The two CA fibers showed wide linear ranges, low detection limits (0.008-0.047μgL(-1) for BTEX, 0.15-5.7μgL(-1) for phenols) and good repeatabilities (RSDs less than 4.6% for BTEX, and less than 9.5% for phenols) and satisfying reproducibilities between fibers (RSDs less than 5.2% for BTEX, and less than 9.9% for phenols). These fibers were successfully used for the analysis of water samples from the Pearl River, which demonstrated the applicability of the home-made CA fibers.

  9. Nanostructured zirconium titanate fibers prepared by particulate sol–gel and cellulose templating techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, P. [Helmerich Advanced Technology Research Center, School of Electrical and Computer Engineering, Oklahoma State University, OK 74106 (United States); Salahinejad, E. [Helmerich Advanced Technology Research Center, School of Material Science and Engineering, Oklahoma State University, OK 74106 (United States); Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Blvd., 7134851154 Shiraz (Iran, Islamic Republic of); Kaul, R. [Department of Biochemistry and Microbiology, Center for Health Sciences, Oklahoma State University, OK 74107 (United States); Vashaee, D. [Helmerich Advanced Technology Research Center, School of Electrical and Computer Engineering, Oklahoma State University, OK 74106 (United States); Tayebi, L., E-mail: lobat.tayebi@okstate.edu [Helmerich Advanced Technology Research Center, School of Material Science and Engineering, Oklahoma State University, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

    2013-08-15

    Highlights: •A method to produce zirconium titanate fibers was introduced. •The resultant structure and photocatalytic activity of the fiber were investigated. •The fiber exhibited higher photocatalytic characteristics, compared with the powders. -- Abstract: In this paper, a method for cost-effective production of nanostructured zirconium titanate (ZrTiO{sub 4}) fibers is introduced. In this method, ZrTiO{sub 4} fibers were synthesized by a sol–gel technique using cellulose fibers as the template. The resultant structures were studied by transmission electron microscopy, X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller (BET) analyses. The photocatalytic activity of the fiber was compared to that of ZrTiO{sub 4} powders prepared by the same sol–gel method, in dark and under UVA and UVC radiations. According to the results, after calcination accompanied by the template removal, the ZrTiO{sub 4} fiber consists of uniformly-deposited, crystalline nanoparticles. This nanostructured fiber exhibited a higher surface area and a higher porosity compared with the ZrTiO{sub 4} powders, resulting in considerably higher photocatalytic characteristics, as confirmed by the experiment. The large surface area and the enhanced photocatalytic activity of the ZrTiO{sub 4} fibers also offer applications in sensors and bioactive films.

  10. Molecularly Designed Stabilized Asymmetric Hollow Fiber Membranes for Aggressive Natural Gas Separation.

    Science.gov (United States)

    Liu, Gongping; Li, Nanwen; Miller, Stephen J; Kim, Danny; Yi, Shouliang; Labreche, Ying; Koros, William J

    2016-10-24

    New rigid polyimides with bulky CF3 groups were synthesized and engineered into high-performance hollow fiber membranes. The enhanced rotational barrier provided by properly positioned CF3 side groups prohibited fiber transition layer collapse during cross-linking, thereby greatly improving CO2 /CH4 separation performance compared to conventional materials for aggressive natural gas feeds. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Cladded single crystal fibers for high power fiber lasers

    Science.gov (United States)

    Kim, W.; Shaw, B.; Bayya, S.; Askins, C.; Peele, J.; Rhonehouse, D.; Meyers, J.; Thapa, R.; Gibson, D.; Sanghera, J.

    2016-09-01

    We report on the recent progress in the development of cladded single crystal fibers for high power single frequency lasers. Various rare earth doped single crystal YAG fibers with diameters down to 17 μm with length > 1 m have been successfully drawn using a state-of-the-art Laser Heated Pedestal Growth system. Single and double cladding on rare earth doped YAG fibers have been developed using glasses where optical and physical properties were precisely matched to doped YAG core single crystal fiber. The double clad Yb:YAG fiber structures have dimensions analogous to large mode area (LMA) silica fiber. We also report successful fabrications of all crystalline core/clad fibers where thermal and optical properties are superior over glass cladded YAG fibers. Various fabrication methods, optical characterization and gain measurements on these cladded YAG fibers are reported.

  12. Hydrogen storage by carbon materials synthesized from oil seeds and fibrous plant materials

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, Maheshwar; Bhardwaj, Sunil; Jaybhaye, Sandesh [Nanotechnology Research Center, Birla College, Kalyan 421304 (India); Soga, T.; Afre, Rakesh [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya (Japan); Sathiyamoorthy, D.; Dasgupta, K. [Powder Metallurgy Division, BARC, Trombay 400 085 (India); Sharon, Madhuri [Monad Nanotech Pvt. Ltd., A702 Bhawani Tower, Powai, Mumbai 400 076 (India)

    2007-12-15

    Carbon materials of various morphologies have been synthesized by pyrolysis of various oil-seeds and plant's fibrous materials. These materials are characterized by SEM and Raman. Surface areas of these materials are determined by methylene blue method. These carbon porous materials are used for hydrogen storage. Carbon fibers with channel type structure are obtained from baggas and coconut fibers. It is reported that amongst the different plant based precursors studied, carbon from soyabean (1.09 wt%) and baggas (2.05 wt%) gave the better capacity to store hydrogen at 11kg/m{sup 2} pressure of hydrogen at room temperature. Efforts are made to correlate the hydrogen adsorption capacity with intensities and peak positions of G- and D-band obtained with carbon materials synthesized from plant based precursors. It is suggested that carbon materials whose G-band is around 1575cm{sup -1} and the intensity of D-band is less compared to G-band, may be useful material for hydrogen adsorption study. (author)

  13. Control of protein adsorption on functionalized electrospun fibers.

    Science.gov (United States)

    Grafahrend, Dirk; Calvet, Julia Lleixa; Klinkhammer, Kristina; Salber, Jochen; Dalton, Paul D; Möller, Martin; Klee, Doris

    2008-10-15

    Electrospun fibers that are protein resistant and functionalized with bioactive signals were produced by solution electrospinning amphiphilic block copolymers. Poly (ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PDLLA) was synthesized in two steps, with a PEG segment of 10 kDa, while the PDLLA block ranged from 20 to 60 kDa. Depending on the PEG and PDLLA segment ratio, as well as solvent selection, the hydrophilicity and protein adsorption could be altered on the electrospun mesh. Furthermore, an alpha-acetal PEG-b-PDLLA was synthesized that allowed the conjugation of active molecules, resulting in surface functionalization of the electrospun fiber. Electrospun material with varying morphologies and diameter were electrospun from 10, 20, and 30 wt.% solutions. Sessile drop measurements showed a reduction in the contact angle from 120 degrees for pure poly(D,L-lactide) with increasing PEG/PDLLA ratio. All electrospun block PEG-b-PDLLA fibers had hydrophilic properties, with contact angles below 45 degrees . The fibers were collected onto six-arm star-poly(ethylene glycol) (star-PEG) coated silicon wafers and incubated with fluorescently labeled proteins. All PEG-b-PDLLA fibers showed no detectable adsorption of bovine serum albumin (BSA) independent of their composition while a dependence between hydrophobic block length was observed for streptavidin adsorption. Fibers of block copolymers with PDLLA blocks smaller than 39 kDa showed no adsorption of BSA or streptavidin, indicating good non-fouling properties. Fibers were surface functionalized with N(epsilon)-(+)-biotinyl-L-lysine (biocytin) or RGD peptide by attaching the molecule to the PEG block during synthesis. Protein adsorption measurements, and the controlled interaction of biocytin with fluorescently labeled streptavidin, showed that the electrospun fibers were both resistant to protein adsorption and are functionalized. Fibroblast adhesion was contrasting between the unfunctionalized and RGD

  14. The formation of web-like connection among electrospun chitosan/PVA fiber network by the reinforcement of ellipsoidal calcium carbonate.

    Science.gov (United States)

    Sambudi, Nonni Soraya; Kim, Minjeong G; Park, Seung Bin

    2016-03-01

    The electrospun fibers consist of backbone fibers and nano-branch network are synthesized by loading of ellipsoidal calcium carbonate in the mixture of chitosan/poly(vinyl alcohol) (PVA) followed by electrospinning. The synthesized ellipsoidal calcium carbonate is in submicron size (730.7±152.4 nm for long axis and 212.6±51.3 nm for short axis). The electrospun backbone fibers experience an increasing in diameter by loading of calcium carbonate from 71.5±23.4 nm to 281.9±51.2 nm. The diameters of branch fibers in the web-network range from 15 nm to 65 nm with most distributions of fibers are in 30-35 nm. Calcium carbonate acts as reinforcing agent to improve the mechanical properties of fibers. The optimum value of Young's modulus is found at the incorporation of 3 wt.% of calcium carbonate in chitosan/PVA fibers, which is enhanced from 15.7±3 MPa to 432.4±94.3 MPa. On the other hand, the ultimate stress of fibers experiences a decrease. This result shows that the fiber network undergoes changes from flexible to more stiff by the inclusion of calcium carbonate. The thermal analysis results show that the crystallinity of polymer is changed by the existence of calcium carbonate in the fiber network. The immersion of fibers in simulated body fluid (SBF) results in the formation of apatite on the surface of fibers.

  15. Synthesizing biomolecule-based Boolean logic gates.

    Science.gov (United States)

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2013-02-15

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, and hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications.

  16. Structure of the enzymatically synthesized fructan inulin

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, A.G.; Schroeer, B. [Max-Planck-Institut fuer Molekulare Pflanzenphysiologie, Karl-Liebknecht-Str. 25, 14476 Golm (Germany); Radosta, S. [Fraunhofer-Institut fuer Angewandte Polymerforschung, Postfach 126, 14504 Teltow (Germany); Wolff, D.; Czapla, S.; Springer, J. [Technische Universitaet Berlin, FG Makromolekulare Chemie, Str. des 17. Juni 135, 10623 Berlin (Germany)

    1998-12-15

    Construction, purification and characterization of a fusion protein of maltose-binding protein of Escherichia coli and the fructosyltransferase of Streptococcus mutans is described. With the purified protein, in vitro synthesis of inulin was performed. The obtained polysaccharide was characterized by high-performance size-exclusion chromatography (HPSEC) and static light scattering (SLS) in dilute aqueous and dimethyl sulfoxide solution. For all samples very high molecular weights between 60x10{sup 6} and 90x10{sup 6} g/mol and a remarkable small polydispersity index of 1.1 have been determined. Small root-mean-square radii of gyration point to a compact conformation in dilute solution. No difference between native and enzymatically synthesized inulin was observed by X-ray powder diffraction and thermoanalysis of solid samples. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. Methods for synthesizing metal oxide nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sunkara, Mahendra Kumar; Kumar, Vivekanand; Kim, Jeong H.; Clark, Ezra Lee

    2016-08-09

    A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.

  18. Energy storage materials synthesized from ionic liquids.

    Science.gov (United States)

    Gebresilassie Eshetu, Gebrekidan; Armand, Michel; Scrosati, Bruno; Passerini, Stefano

    2014-12-01

    The advent of ionic liquids (ILs) as eco-friendly and promising reaction media has opened new frontiers in the field of electrochemical energy storage. Beyond their use as electrolyte components in batteries and supercapacitors, ILs have unique properties that make them suitable as functional advanced materials, media for materials production, and components for preparing highly engineered functional products. Aiming at offering an in-depth review on the newly emerging IL-based green synthesis processes of energy storage materials, this Review provides an overview of the role of ILs in the synthesis of materials for batteries, supercapacitors, and green electrode processing. It is expected that this Review will assess the status quo of the research field and thereby stimulate new thoughts and ideas on the emerging challenges and opportunities of IL-based syntheses of energy materials.

  19. The Complexity of Synthesizing Uniform Strategies

    Directory of Open Access Journals (Sweden)

    Bastien Maubert

    2013-03-01

    Full Text Available We investigate uniformity properties of strategies. These properties involve sets of plays in order to express useful constraints on strategies that are not μ-calculus definable. Typically, we can state that a strategy is observation-based. We propose a formal language to specify uniformity properties, interpreted over two-player turn-based arenas equipped with a binary relation between plays. This way, we capture e.g. games with winning conditions expressible in epistemic temporal logic, whose underlying equivalence relation between plays reflects the observational capabilities of agents (for example, synchronous perfect recall. Our framework naturally generalizes many other situations from the literature. We establish that the problem of synthesizing strategies under uniformity constraints based on regular binary relations between plays is non-elementary complete.

  20. Simplification of Methods for PET Radiopharmaceutical Syntheses

    Energy Technology Data Exchange (ETDEWEB)

    Kilbourn, Michael, R.

    2011-12-27

    In an attempt to develop simplified methods for radiochemical synthesis of radiopharmaceuticals useful in Positron Emission Tomography (PET), current commercially available automated synthesis apparati were evaluated for use with solid phase synthesis, thin-film techniques, microwave-accelerated chemistry, and click chemistry approaches. Using combinations of these techniques, it was shown that these automated synthesis systems can be simply and effectively used to support the synthesis of a wide variety of carbon-11 and fluorine-18 labeled compounds, representing all of the major types of compounds synthesized and using all of the common radiochemical precursors available. These techniques are available for use to deliver clinically useful amounts of PET radiopharmaceuticals with chemical and radiochemical purities and high specific activities, suitable for human administration.

  1. Method and apparatus for synthesizing hydrocarbons

    Science.gov (United States)

    Colmenares, C.A.; Somorjai, G.A.; Maj, J.J.

    1985-04-16

    A method and apparatus for synthesizing a mixture of aliphatic alcohols having five carbons or less is disclosed. An equal molar ratio of CO and H/sub 2/ gases is caused to pass through a ThO/sub 2/ catalyst having a surface area of about 80 to 125 m/sup 2//g. The catalyst further optionally includes Na ions present as substitutional cations in an amount of about 5 to 10 atom %. At a temperature of about 570 to 630/sup 0/K, and at pressures of about 20 to 50 atm, methanol and isobutanol are the predominant products and are produced in amounts of about 90 wt % of the total hydrocarbon mixture. 6 figs.

  2. Using quantum mechanics to synthesize electronic devices

    Science.gov (United States)

    Schmidt, Petra; Levi, Anthony

    2005-03-01

    Adaptive quantum design [1] has been used to explore the possibility of creating new classes of electronic semiconductor devices. We show how non-equilibrium electron transmission through a synthesized conduction band potential profile can be used to obtain a desired current - voltage characteristic. We illustrate our methodology by designing a two-terminal linear resistive element in which current is limited by quantum mechanical transmission through a potential profile and power is dissipated non-locally in the electrodes. As electronic devices scale to dimensions in which the physics of operation is dominated by quantum mechanical effects, classical designs fail to deliver the desired functionality. Our device synthesis approach is a way to realize device functionality that may not otherwise be achieved. [1] Y.Chen, R.Yu, W.Li, O.Nohadani, S.Haas, A.F.J. Levi, Journal of Applied Physics, Vol.94, No.9, p6065, 2003

  3. National Gas Survey. Synthesized gaseous hydrocarbon fuels

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    The supply-Technical Advisory Task Force-Synthesized Gaseous Hydrocarbon Fuels considered coal, hydrocarbon liquids, oil shales, tar sands, and bioconvertible materials as potential feedstocks for gaseous fuels. Current status of process technology for each feedstock was reviewed, economic evaluations including sensitivity analysis were made, and constraints for establishment of a synthesized gaseous hydrocarbon fuels industry considered. Process technology is presently available to manufacture gaseous hydrocarbon fuels from each of the feedstocks. In 1975 there were eleven liquid feedstock SNG plants in the United States having a capacity of 1.1 billion SCFD. There can be no contribution of SNG before 1982 from plants using feedstocks other than liquids because there are no plants in operation or under construction as of 1977. Costs for SNG are higher than current regulated prices for U.S. natural gas. Because of large reserves, coal is a prime feedstock candidate although there are major constraints in the area of coal leases, mining and water permits, and others. Commercial technology is available and several new gasification processes are under development. Oil shale is also a feedstock in large supply and commercial process technology is available. There are siting and permit constraints, and water availability may limit the ultimate size of an oil shale processing industry. Under projected conditions, bioconvertible materials are not expected to support the production of large quantities of pipeline quality gas during the next decade. Production of low or medium Btu gas from municipal solid wastes can be expected to be developed in urban areas in conjunction with savings in disposal costs. In the economic evaluations presented, the most significant factor for liquid feedstock plants is the anticipated cost of feedstock and fuel. The economic viability of plants using other feedstocks is primarily dependent upon capital requirements.

  4. Syntheses and Structure Determinations of Calcium Thiolates.

    Science.gov (United States)

    Chadwick, Scott; Englich, Ulrich; Noll, Bruce; Ruhlandt-Senge, Karin

    1998-09-07

    The exploration of synthetic methodologies toward heavy alkaline-earth chalcogenolates resulted in the preparation and structural characterization of a family of calcium thiolates, including [Ca(SC(6)F(5))(2)(py)(4)], 1 (py = pyridine), the separated ion-triple [Ca(18-crown-6)(NH(3))(3))][SMes](2).2THF, 2 (Mes = 2,4,6-tBu(3)C(6)H(2)), and the contact triple [Ca(18-crown-6)(SMes)(2)].THF, 3. Compound 1 was prepared by treating [Ca(N(SiMe(3))(2))(2)](2) with 4 equiv of HSC(6)F(5) under addition of pyridine. The thiolates 2 and 3 were synthesized by treatment of calcium metal dissolved in dry, liquid NH(3) under addition of 2 equiv of HSMes and crown ether or, alternatively, by the reduction of MesSSMes with calcium metal in dry, liquid ammonia. We also report two reaction products isolated during attempted calcium thiolate syntheses: [CaBr(4)(THF)(2)(&mgr;(2)-Li)(2)(THF)(4)], 4, isolated as the product of a salt elimination reaction between CaBr(2) and 2 equiv of [Li(THF)(n)()S-2,4,6-(i)()Pr(3)C(6)H(2)](m)(). [(NH(4))(py)(SC(6)F(5))], 5, was obtained as the sole product in the reaction of metallic calcium with HSC(6)F(5) in liquid ammonia under addition of pyridine. All compounds were characterized by single-crystal X-ray crystallography in addition to IR and NMR spectroscopy.

  5. Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength

    DEFF Research Database (Denmark)

    Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda;

    2011-01-01

    A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...

  6. Modal characterization of fiber-to-fiber coupling processes.

    Science.gov (United States)

    Flamm, Daniel; Hou, Kai-Chung; Gelszinnis, Philipp; Schulze, Christian; Schröter, Siegmund; Duparré, Michael

    2013-06-15

    We present a detailed experimental investigation of a fiber-to-fiber coupling process by characterizing the mode content at the output of the system. In our experiment a single-mode fiber is transversally scanned with respect to a multimode fiber, revealing position-dependent higher-order mode excitation. The outlined measurement system can be used for automated optimization of fundamental mode content and beam quality. Additionally, our approach characterizes the modal transmission properties of the multimode waveguide in its present state and is hence of high relevance for the conception of transport fibers and fiber laser systems.

  7. Erbium doped random fiber laser and fiber mixing effect

    OpenAIRE

    Yao, Can; Thévenaz, Luc; Brès, Camille Sophie

    2017-01-01

    We demonstrate an active random fiber laser by directly pumping a 100 m erbium-doped fiber at 980 nm wavelength, with a fiber loop mirror forming a half-open cavity. Random lasing with competing spectral modes in the range from 1535 nm to 1560 nm is achieved, with the maximum lasing slope efficiency around 10%. We also study the effect of combining a dispersion compensated fiber with the erbium-doped fiber. The kilometers long dispersion compensated fiber reduces the random lasing threshold a...

  8. Enantioselective catalytic syntheses of alpha-branched chiral amines

    DEFF Research Database (Denmark)

    Brase, S.; Baumann, T.; Dahmen, S.

    2007-01-01

    Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials.......Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials....

  9. Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins.

    Science.gov (United States)

    Gainer, Harold; House, Shirley; Kim, Dong Sun; Chin, Hemin; Pant, Harish C

    2017-04-01

    When isolated squid giant axons are incubated in radioactive amino acids, abundant newly synthesized proteins are found in the axoplasm. These proteins are translated in the adaxonal Schwann cells and subsequently transferred into the giant axon. The question as to whether any de novo protein synthesis occurs in the giant axon itself is difficult to resolve because the small contribution of the proteins possibly synthesized intra-axonally is not easily distinguished from the large amounts of the proteins being supplied from the Schwann cells. In this paper, we reexamine this issue by studying the synthesis of endogenous neurofilament (NF) proteins in the axon. Our laboratory previously showed that NF mRNA and protein are present in the squid giant axon, but not in the surrounding adaxonal glia. Therefore, if the isolated squid axon could be shown to contain newly synthesized NF protein de novo, it could not arise from the adaxonal glia. The results of experiments in this paper show that abundant 3H-labeled NF protein is synthesized in the squid giant fiber lobe containing the giant axon's neuronal cell bodies, but despite the presence of NF mRNA in the giant axon no labeled NF protein is detected in the giant axon. This lends support to the glia-axon protein transfer hypothesis which posits that the squid giant axon obtains newly synthesized protein by Schwann cell transfer and not through intra-axonal protein synthesis, and further suggests that the NF mRNA in the axon is in a translationally repressed state.

  10. Toward high performance graphene fibers.

    Science.gov (United States)

    Chen, Li; He, Yuling; Chai, Songgang; Qiang, Hong; Chen, Feng; Fu, Qiang

    2013-07-07

    Two-dimensional graphene and graphene-based materials have attracted tremendous interest, hence much attention has been drawn to exploring and applying their exceptional characteristics and properties. Integration of graphene sheets into macroscopic fibers is a very important way for their application and has received increasing interest. In this study, neat and macroscopic graphene fibers were continuously spun from graphene oxide (GO) suspensions followed by chemical reduction. By varying wet-spinning conditions, a series of graphene fibers were prepared, then, the structural features, mechanical and electrical performances of the fibers were investigated. We found the orientation of graphene sheets, the interaction between inter-fiber graphene sheets and the defects in the fibers have a pronounced effect on the properties of the fibers. Graphene fibers with excellent mechanical and electrical properties will yield great advances in high-tech applications. These findings provide guidance for the future production of high performance graphene fibers.

  11. Crosslinking of Kapok Cellulose Fiber via Azide Alkyne Click Chemistry as a New Material for Filtering System: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Nur Syazwani Abd Rahman

    2016-01-01

    Full Text Available A new class of green material has been elaborated by grafting the modified kapok fiber, by the means of azidated kapok fiber followed by “click-chemistry” reaction with the terminal alkyne crosslinker. The modified and synthesized product was characterized using Fourier transform infrared spectroscopy (FT-IR, and Scanning electron microscopy (SEM. The study also was undertaken to investigate the effect on the absorption of methylene blue from aqueous solution onto the click fiber prepared. The findings showed that the click kapok absorbed more compared to the untreated kapok. Based on the result, the reaction of click chemistry influenced the properties of the filter made from kapok fiber.

  12. Fiber-optic technology review

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, P.B.

    1980-01-01

    A history of fiber technology is presented. The advantages of fiber optics are discussed (bandwidth, cost, weight and size, nonmetallic construction and isolation). Some aspects of the disadvantages of fiber systems briefly discussed are fiber and cable availability, fiber components, radiation effects, receivers and transmitters, and material dispersion. Particular emphasis over the next several years will involve development of fibers and systems optimized for use at wavelengths near 1.3 ..mu..m and development of wavelengths multiplexers for simultaneous system operation at several wavelengths.

  13. Nonlinear effects in optical fibers

    CERN Document Server

    Ferreira, Mario F

    2011-01-01

    Cutting-edge coverage of nonlinear phenomena occurring inside optical fibers Nonlinear fiber optics is a specialized part of fiber optics dealing with optical nonlinearities and their applications. As fiber-optic communication systems have become more advanced and complex, the nonlinear effects in optical fibers have increased in importance, as they adversely affect system performance. Paradoxically, the same nonlinear phenomena also offer the promise of addressing the bandwidth bottleneck for signal processing for future ultra-high speed optical networks. Nonlinear Effects in Optical Fiber

  14. ZBLAN Fiber Phase B Study

    Science.gov (United States)

    Workman, Gary L.; Smith, Guy A.

    1997-01-01

    A Phase B feasibility study will be performed for the study of the effects of microgravity on the preform processing and fiber pulling of ZBLAN optical glass. Continuing from the positive results achieved in the fiber annealing experiments in 20 second intervals at 0.001 g on the KC-135 and the 5 minute experiments on the SPAR rocket, experiments will continue to work towards design of a fiber sting to initiate fiber pulling operations in space. Anticipated results include less homogeneous nucleation than ground-based annealed fibers. Infrared Fiber Systems and Galileo are the participating industrial investigators.

  15. Directionally solidified mullite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Sayir, A. [Case Western Reserve Univ., Cleveland, OH (United States); Farmer, S.C. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

    1995-10-01

    Directionally solidified fibers with nominal mullite compositions of 3Al{sub 2}O{sub 3} {center_dot} 2SiO{sub 2} were grown by the laser heated float zone (LHFZ) method at NASA Lewis. High resolution digital images from an optical microscope evidence the formation of a liquid-liquid miscibility gap during crystal growth. Experimental evidence shows that the formation of mullite in aluminosilicate melts is in fact preceded by liquid immiscibility. The average fiber tensile strength is 1.15 GPa at room temperature. The mullite fibers retained 80% of their room temperature tensile strength at 1,450 C. SEM analysis revealed that the fibers were strongly faceted and that the facets act as critical flaws. Examined in TEM, these mullite single crystals are free of dislocations, low angle boundaries and voids. Single crystal mullite showed a high degree of oxygen vacancy ordering. Regardless of the starting composition, the degree of order observed in polycrystalline fibers was lower than that observed in the mullite single crystals.

  16. Characterization of defects of mullite fibers prepared by polyvinyl butyral as spinning aid

    Directory of Open Access Journals (Sweden)

    Zhang Y.B.

    2010-01-01

    Full Text Available Mullite fibers have been synthesized using polyvinyl butyral as spinning aids. Defects including cracks, core-sheath structure, randomly arranged powders, shots and rough surface were observed. The results showed that circumferential cracks were terminated by the main axial crack. The thermal shrinkage could be considered as the reason for the formation of cracks and core-sheath structure. Improper control of heat treatment resulted in the rough surface around fibers. The wet gel fibers were easily inserted by some alumina powders which were used to obtain the uniform shrinkage during calcinations in the kiln.

  17. Polydimethylsiloxane fibers for optical fiber sensor of displacement

    Science.gov (United States)

    Martincek, Ivan; Pudis, Dusan; Gaso, Peter

    2013-09-01

    The paper describes the preparation of polydimethylsiloxane (PDMS) fiber integrated on the conventional optical fibers and their use for optical fiber displacement sensor. PDMS fiber was made of silicone elastomer Sylgard 184 (Dow Corning) by drawing from partially cured silicone. Optical fiber displacement sensor using PDMS fiber is based on the measurement of the local minimum of optical signal in visible spectral range generated by intermodal interference of circularly symmetric modes. Position of the local minimum in spectral range varies by stretching the PDMS fiber of 230 μm in the wavelength range from 688 to 477 nm. In the stretched PDMS fiber is possible to determine the longitudinal displacement with an accuracy of approximately 1 micrometer.

  18. Automatic Fiber Orientation Detection for Sewed Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Automatic production and precise positioning of carbon fiber reinforced plastics (FRP) require precise detection of the fiber orientations. This paper presents an automatic method for detecting fiber orientations of sewed carbon fibers in the production of FRP. Detection was achieved by appropriate use of regional filling, edge detection operators, autocorrelation methods, and the Hough transformation. Regional filling was used to reduce the influence of the sewed regions, autocorrelation was used to clarify the fiber directions, edge detection operators were used to extract the edge features for the fiber orientations, and the Hough transformation was used to calculate the angles. Results for two kinds of carbon fiber materials show that the method is relatively quick and precise for detecting carbon fiber orientations.

  19. Localization of ANP-synthesizing cells in rat stomach

    Institute of Scientific and Technical Information of China (English)

    Chun-Hui Li; Li-Hui Pan; Chun-Yu Li; Chang-Lin Zhu; Wen-Xie Xu

    2006-01-01

    AIM: To study the morphological positive expression of antrial natriuretic peptide (ANP)-synthesizing cells and ultrastructural localization and the relationship between ANP-synthesizing cells and microvessel density in the stomach of rats and to analyze the distribution of the three histologically distinct regions of ANP-synthesizing cells.METHODS: Using immunohistochemical techniques, we studied positive expression of ANP-synthesizing cells in rat stomach. A postembedding immunogold microscopy technique was used for ultrastructural localization of ANP-synthesizing cells. Microvessel density in the rat stomach was estimated using tannic acid-ferric chloride (TAFC) method staining. Distribution of ANP-synthesizing cells were studied in different regions of rat stomach histochemically.RESULTS: Positive expression of ANP-synthesizing cells were localized in the gastric mucosa of rats. Localization of ANP-synthesizing cells identified them to be enterochrochromaffin cells (EC) by using a postembedding immunogold electron microscopy technique. EC cells were in the basal third of the cardiac mucosa region.ANP-synthesizing cells existed in different regions of rat stomach and its density was largest in the gastric cardiac region, and the distribution order of ANP-synthesizing cells in density was cardiac region, pyloric region and fundic region in mucosa layer. We have also found a close relationship between ANP-synthesizing cells and microvessel density in gastric mucosa of rats using TAFC staining.CONCLUSION: ANP-synthesizing cells are expressed in the gastric mucosa. EC synthesize ANP. There is a close relationship between ANP-synthesizing cells and microvessel density in gastric mucosa of rats.The distribution density of ANP-synthesizing cells is largest in the gastric cardiac region.

  20. Strong, damage tolerant oxide-fiber/oxide matrix composites

    Science.gov (United States)

    Bao, Yahua

    Electrophoretic deposition (EPD) is an easy and cost effective method to fabricate fiber-reinforced green composites. Non-conductive Nextel(TM) 720 fibers were successfully coated with a transient, conductive polypyrrole submicron surface layer for use directly as an electrode in EPD processing. However, electric-field shielding limits particle infiltration into the conductive fiber bundles and they mostly deposit on the outer surface of the fiber bundle. When the bundle is large, central cavities exist after deposition. The EPD cell was modified for electrophoretic infiltration deposition (EPID). Non conductive fibers were laid on an electrode and charged particles in an ethanol suspension are driven there through by an electric field, infiltrate and deposit on the electrode to then build up into the fiber preform and fill the voids therein. Dense, uniform, green fiber composites were successfully fabricated via constant current EPID. The EPID process is modeled as capillary electrophoretic infiltration. The process consists of two steps: particle electrophoresis outside the capillaries and electrophoretic infiltration inside the capillaries. Due to the zero net flow of the ethanol across the capillary cross-section, there is no electro-osmotic flow contribution to the deposition rate. Hamaker's law was extended to the EPID process, i.e., the deposition yield is proportional to the electric field inside the capillaries. The total deposition yield is controlled by the slow step of the process, i.e., the rate of electrophoresis in the open suspension outside the capillaries. AlPO4 was proposed as a weak layer between oxide fibers and oxide matrix in fiber-reinforced ceramic matrix composites (CMC's). AlPO 4 nano particles were synthesized by chemical co-precipitation of Al 3+ and HPO42- with urea at 95°C. The solution pH basic region and amorphous AlPO4 precipitated of narrow size distribution with a mean particle size 50nm. Nextel 720 fibers were pretreated with

  1. Porous core-shell carbon fibers derived from lignin and cellulose nanofibrils

    KAUST Repository

    Xu, Xuezhu

    2013-10-01

    This letter reports a method to produce lignin and cellulose nanofibrils (CNFs) based porous core-shell carbon fibers via co-electrospinning followed by controlled carbonization. Lignin formed the shell of the fiber while CNF network formed the porous core. Polyacrylonitrile (PAN) was added to the lignin solution to increase its electrospinability. CNFs were surface acetylated and dispersed in silicon oil to obtain a homogenous dispersion for electrospinning the porous core. Hollow lignin fibers were also electrospun using glycerin as the core material. FT-IR measurements confirmed the CNF acetylation. SEM micrographs showed the core-shell and hollow fiber nanostructures before and after carbonization. The novel carbon fibers synthesized in this study exhibited increased surface area and porosity that are promising for many advanced applications. © 2013 Elsevier B.V.

  2. Development of Coconut Trunk Fiber Geopolymer Hybrid Composite for Structural Engineering Materials

    Science.gov (United States)

    Amalia, F.; Akifah, N.; Nurfadilla; Subaer

    2017-03-01

    A research on the influence of coconut fiber trunk on mechanical properties based on fly ash has been conducted. The aims of this study was to examine the mechanical properties of geopolymer composites by varrying the concentration of coconut trunk fiber. Geopolymer synthesized by alkali activated (NaOH+H2O+Na2O.3SiO2) and cured at the temperature 700C for one hour. Specimens were synthesized into 5 different mass of fiber 0 g, 0.25 g, 0.50 g, 0.75 g, and 1.00 g keeping fly ash constant. The highest compressive strength was 89.44 MPa for specimen added with 0.50 g of fiber. The highest flexural strength was 7.64 MPa for the same sample. The interfacial transition zone (ITZ) between the matrix of geopolymers and coconut fiber was conducted by using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). The chemical composition of the specimen was examined by using X-Ray Diffraction (XRD). The thermal properties of coconut fiber trunk was analyzed using Differential Scanning Calorimetry (DSC). It was found that coconut fiber was able to improve the mechanical and microstructure properties of geopolymers composites.

  3. Femtosecond Fiber Lasers

    Science.gov (United States)

    Bock, Katherine J.

    This thesis focuses on research I have done on ytterbium-doped femtosecond fiber lasers. These lasers operate in the near infrared region, lasing at 1030 nm. This wavelength is particularly important in biomedical applications, which includes but is not limited to confocal microscopy and ablation for surgical incisions. Furthermore, fiber lasers are advantageous compared to solid state lasers in terms of their cost, form factor, and ease of use. Solid state lasers still dominate the market due to their comparatively high energy pulses. High energy pulse generation in fiber lasers is hindered by either optical wave breaking or by multipulsing. One of the main challenges for fiber lasers is to overcome these limitations to achieve high energy pulses. The motivation for the work done in this thesis is increasing the output pulse peak power and energy. The main idea of the work is that decreasing the nonlinearity that acts on the pulse inside the cavity will prevent optical wave breaking, and thus will generate higher energy pulses. By increasing the output energy, ytterbium-doped femtosecond fiber lasers can be competitive with solid state lasers which are used commonly in research. Although fiber lasers tend to lack the wavelength tuning ability of solid state lasers, many biomedical applications take advantage of the 1030 microm central wavelength of ytterbium-doped fiber lasers, so the major limiting factor of fiber lasers in this field is simply the output power. By increasing the output energy without resorting to external amplification, the cavity is optimized and cost can remain low and economical. During verification of the main idea, the cavity was examined for possible back-reflections and for components with narrow spectral bandwidths which may have contributed to the presence of multipulsing. Distinct cases of multipulsing, bound pulse and harmonic mode-locking, were observed and recorded as they may be of more interest in the future. The third

  4. Vector Soliton Fiber Lasers

    CERN Document Server

    Zhang, Han

    2011-01-01

    Solitons, as stable localized wave packets that can propagate long distance in dispersive media without changing their shapes, are ubiquitous in nonlinear physical systems. Since the first experimental realization of optical bright solitons in the anomalous dispersion single mode fibers (SMF) by Mollenauer et al. in 1980 and optical dark solitons in the normal dispersion SMFs by P. Emplit et al. in 1987, optical solitons in SMFs had been extensively investigated. In reality a SMF always supports two orthogonal polarization modes. Taking fiber birefringence into account, it was later theoretically predicted that various types of vector solitons, including the bright-bright vector solitons, dark-dark vector solitons and dark-bright vector solitons, could be formed in SMFs. However, except the bright-bright type of vector solitons, other types of vector solitons are so far lack of clear experimental evidence. Optical solitons have been observed not only in the SMFs but also in mode locked fiber lasers. It has be...

  5. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber-laser...... cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  6. Compact fiber optic accelerometer

    Institute of Scientific and Technical Information of China (English)

    Feng Peng; Jun Yang; Bing Wu; Yonggui Yuan; Xingliang Li; Ai Zhou; Libo Yuan

    2012-01-01

    A compact fiber optic accelerometer based on a Michelson interferometer is proposed and demonstrated.In the proposed system,the sensing element consists of two single-mode fibers glued together by epoxy,which then act as a simple supported beam.By demodulating the optical phase shift,the acceleration is determined as proportional to the force applied on the central position of the two single-mode fibers.This simple model is able to calculate the sensitivity and the resonant frequency of the compact accelerometer.The experimental results show that the sensitivity and the resonant frequency of the accelerometer are 0.42 rad/g and 600 Hz,respectively.

  7. Copper nanocoils synthesized through solvothermal method

    Science.gov (United States)

    Liu, Yanjuan; Liu, Xiaowei; Zhan, Yongjie; Fan, Haiming; Lu, Yang

    2015-11-01

    Recently helical nanostructures such as nanosprings and nanocoils have drawn great interests in nanotechnology, due to their unique morphologies and physical properties, and they may be potential building blocks in sorts of electromechanical, magnetic, photoelectronic and plasmonic devices at micro/nanoscales. In this report, multi-turns copper nanocoils were synthesized through a modified solvothermal method, in which the mixture of water and N-methyl-2-pyrrolidone (NMP) were selected as reaction medium and copolymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA 64E) as reductant. In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity. These nanocoils and nanosprings are of single crystalline structure, with the characteristics wire diameters ranging from tens to a few hundreds of nanometers and the ring/coil diameters mostly ~10-35 microns. Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings. This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.

  8. Measuring and Synthesizing Systems in Probabilistic Environments

    CERN Document Server

    Chatterjee, Krishnendu; Jobstmann, Barbara; Singh, Rohit

    2010-01-01

    Often one has a preference order among the different systems that satisfy a given specification. Under a probabilistic assumption about the possible inputs, such a preference order is naturally expressed by a weighted automaton, which assigns to each word a value, such that a system is preferred if it generates a higher expected value. We solve the following optimal-synthesis problem: given an omega-regular specification, a Markov chain that describes the distribution of inputs, and a weighted automaton that measures how well a system satisfies the given specification under the given input assumption, synthesize a system that optimizes the measured value. For safety specifications and measures that are defined by mean-payoff automata, the optimal-synthesis problem amounts to finding a strategy in a Markov decision process (MDP) that is optimal for a long-run average reward objective, which can be done in polynomial time. For general omega-regular specifications, the solution rests on a new, polynomial-time al...

  9. Computational Models to Synthesize Human Walking

    Institute of Scientific and Technical Information of China (English)

    Lei Ren; David Howard; Laurence Kenney

    2006-01-01

    The synthesis of human walking is of great interest in biomechanics and biomimetic engineering due to its predictive capabilities and potential applications in clinical biomechanics, rehabilitation engineering and biomimetic robotics. In this paper,the various methods that have been used to synthesize humanwalking are reviewed from an engineering viewpoint. This involves a wide spectrum of approaches, from simple passive walking theories to large-scale computational models integrating the nervous, muscular and skeletal systems. These methods are roughly categorized under four headings: models inspired by the concept of a CPG (Central Pattern Generator), methods based on the principles of control engineering, predictive gait simulation using optimisation, and models inspired by passive walking theory. The shortcomings and advantages of these methods are examined, and future directions are discussed in the context of providing insights into the neural control objectives driving gait and improving the stability of the predicted gaits. Future advancements are likely to be motivated by improved understanding of neural control strategies and the subtle complexities of the musculoskeletal system during human locomotion. It is only a matter of time before predictive gait models become a practical and valuable tool in clinical diagnosis, rehabilitation engineering and robotics.

  10. Why can't vertebrates synthesize trehalose?

    Science.gov (United States)

    Argüelles, Juan-Carlos

    2014-10-01

    The non-reducing disaccharide trehalose is a singular molecule, which has been strictly conserved throughout evolution in prokaryotes (bacteria and archaea), lower eukaryotes, plants, and invertebrates, but is absent in vertebrates and-more specifically-in mammals. There are notable differences regarding the pivotal roles played by trehalose among distantly related organisms as well as in the specific metabolic pathways of trehalose biosynthesis and/or hydrolysis, and the regulatory mechanisms that control trehalose expression genes and enzymatic activities. The success of trehalose compared with that of other structurally related molecules is attributed to its exclusive set of physical properties, which account for its physiological roles and have also promoted important biotechnological applications. However, an intriguing question still remains: why are vertebrates in general, and mammals in particular, unable (or have lost the capacity) to synthesize trehalose? The search for annotated genomes of vertebrates reveals the absence of any functional trehalose synthase gene. Indeed, this is also true for the human genome, which contains, however, two genes encoding for isoforms of the hydrolytic activity (trehalase). Although we still lack a convincing answer, this striking difference might reflect the divergent evolutionary lineages followed by invertebrates and vertebrates. Alternatively, some clinical data point to trehalose as a toxic molecule when stored inside the human body.

  11. Enantioselective Syntheses of (-)- and (+)-Homocitric Acid Lactones.

    Science.gov (United States)

    Rodríguez R, Gastón H.; Biellmann, Jean-François

    1996-03-08

    Highly enantioselective syntheses of enantiomers of homocitric acid lactones (R)-5a and (S)-5b are described. Thermal Diels-Alder cycloadditions of 2a and 2b to 1,3-butadiene produced adducts 3a and 3b, respectively. Oxidative ozonolysis of latter adducts gave products 4a and 4b which after acid treatment afforded a mixture with 5a and 5b as major component. Acid lactones 5a and 5b were converted into their dimethyl esters 6a and 6b which were purified by chromatography. After saponification, the products obtained were crystallized to yield (-)- and (+)-homocitric acid lactones ((R)-5a and (S)-5b). Diastereomeric excess (de) of Diels-Alder adducts 3a and 3b was determined by means of Mosher esters of glycols 8a, 8b, and racemic 8. Diels-Alder cycloaddition products of lactones 2a and 2b to 1,3-butadiene showed a diastereoselectivity of 96%.

  12. Syntheses of surfactants from oleochemical epoxides

    Directory of Open Access Journals (Sweden)

    Warwel Siegfried

    2001-01-01

    Full Text Available Sugar-based surfactants were obtained in good yields (up to 100% under mild conditions (70°C, methanol or mixtures of methanol and water by ring-opening of terminal epoxides with aminopolyols, derived from glucose. Reaction of N-methyl glucamine with epoxides from even-numbered C4-C18 alpha-olefins or from terminal unsaturated fatty acid methyl esters leads to linear products, while corresponding reactions with N-dodecyl glucamine or glucamine yield surfactants with different Y-structures. Products obtained by conversion of omega-epoxy fatty acid methyl esters were saponificated with NaOH or hydrolyzed enzymatically to sodium salts or free acids respectively, which are amphoteric surfactants. Studies of the surfactants at different pH-values demonstrate different surface active properties in aqueous solutions. Critical micelle concentrations (c.m.c. in a range between 2 and 500mg/l and surface tensions of 25-40mN/m were measured for several of the synthesized sugar-based surfactants. The ring-opening products are rather poor foamers, whereas some of the corresponding hydrobromides show good foaming properties.

  13. Multistep sintering to synthesize fast lithium garnets

    Science.gov (United States)

    Xu, Biyi; Duan, Huanan; Xia, Wenhao; Guo, Yiping; Kang, Hongmei; Li, Hua; Liu, Hezhou

    2016-01-01

    A multistep sintering schedule is developed to synthesize Li7La3Zr2O12 (LLZO) doped with 0.2 mol% Al3+. The effect of sintering steps on phase, relative density and ionic conductivity of Al-doped LLZO has been evaluated using powder X-Ray diffraction (XRD), scanning electron microscopy (SEM), 27Al magic spinning nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that by holding the sample at 900 °C for 6 h, the mixture of tetragonal and cubic garnet phases are obtained; by continuously holding at 1100 °C for 6 h, the tetragonal phase completely transforms into cubic phase; by holding at 1200 °C, the relative density increases without decomposition of the cubic phase. The Al-LLZO pellets after multistep sintering exhibit cubic phase, relative density of 94.25% and ionic conductivity of 4.5 × 10-4 S cm-1 at room temperature. Based on the observation, a sintering model is proposed and discussed.

  14. Single fiber pullout from hybrid fiber reinforced concrete

    NARCIS (Netherlands)

    Markovich, I.; Van Mier, J.G.M.; Walraven, J.C.

    2001-01-01

    Hybrid fiber reinforcement can be very efficient for improving the tensile response of the composite. In such materials, fibers of different geometries can act as bridging mechanisms over cracks of different widths. The fiber bridging efficiency depends on the interface properties, which makes inter

  15. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  16. Optical fiber rotation sensing

    CERN Document Server

    Burns, William K; Kelley, Paul

    1993-01-01

    Optical Fiber Rotation Sensing is the first book devoted to Interferometric Fiber Optic Gyros (IFOG). This book provides a complete overview of IFOGs, beginning with a historical review of IFOG development and including a fundamental exposition of basic principles, a discussion of devices and components, and concluding with industry reports on state-of-the-art activity. With several chapters contributed by principal developers of this solid-state device, the result is an authoritative work which will serve as the resource for researchers, students, and users of IFOGs.* * State-of-t

  17. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  18. The dentate mossy fibers

    DEFF Research Database (Denmark)

    Blaabjerg, Morten; Zimmer, Jens

    2007-01-01

    Hippocampal mossy fibers are the axons of the dentate granule cells and project to hippocampal CA3 pyramidal cells and mossy cells of the dentate hilus (CA4) as well as a number of interneurons in the two areas. Besides their role in hippocampal function, studies of which are still evolving and t....... These features are the topic of this review, which will use the mossy fiber system of the rat as basis and reference in its aim to provide an up-to-date, yet historically based guide to students in the field...

  19. Optical fiber telecommunications IIIb

    CERN Document Server

    Koch, Thomas L

    2012-01-01

    Updated to include the latest information on light wave technology, Optical Fiber Telecommunication III, Volumes A & B are invaluable for scientists, students, and engineers in the modern telecommunications industry. This two-volume set includes the most current research available in optical fiber telecommunications, light wave technology, and photonics/optoelectronics. The authors cover important background concepts such as SONET, coding device technology, andWOM components as well as projecting the trends in telecommunications for the 21st century.Key Features* One of the hottest subjects of

  20. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Science.gov (United States)

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-12-01

    We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol-gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl2, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  1. Fiber MOPA for Ascends Project

    Data.gov (United States)

    National Aeronautics and Space Administration — CO2 sensing using absorption bands near 1570nm is very attractive by taking advantage of the mature fiber-amplifier technology derived from fiber-optic telecom...

  2. Fused-Polished Fiber Couplers

    Institute of Scientific and Technical Information of China (English)

    Sien; Chi; Shiao-Min; Tseng

    2003-01-01

    We report on fused-polished fiber couplers with a new fabrication method. This structure so fabricated is promising while achieving high-performance all-fiber WDM devices. Potential advantages and prospects of our works are presented.

  3. Fiber optic sensing and imaging

    CERN Document Server

    2013-01-01

    This book is designed to highlight the basic principles of fiber optic imaging and sensing devices. The editor has organized the book to provide the reader with a solid foundation in fiber optic imaging and sensing devices. It begins with an introductory chapter that starts from Maxwell’s equations and ends with the derivation of the basic optical fiber characteristic equations and solutions (i.e. fiber modes). Chapter 2 reviews most common fiber optic interferometric devices and Chapter 3 discusses the basics of fiber optic imagers with emphasis on fiber optic confocal microscope. The fiber optic interferometric sensors are discussed in detail in chapter 4 and 5. Chapter 6 covers optical coherence tomography and goes into the details of signal processing and systems level approach of the real-time OCT implementation. Also useful forms of device characteristic equations are provided so that this book can be used as a reference for scientists and engineers in the optics and related fields.

  4. Dietary fiber and breast cancer.

    Science.gov (United States)

    Cohen, L A

    1999-01-01

    The Fiber Hypothesis which had its origins in the work of Burkitt and others in the early 1970's, focussed largely on fiber's beneficial effects on colon cancer and disorders of the gastric intestinal tract. In the 1980's it was proposed that fiber may also have beneficial effects on breast cancer and a rational for this was proposed involving modulation, by fiber, of the enterohepatic recirculation of estrogens. In the following the evidence from epidemiology, clinical interventions and animal model studies, supporting a role for fiber in breast cancer is critically reviewed. Evidence from animal model studies support the notion that supplementary fiber inhibits chemically-induced mammary tumorigenesis but do not support an estrogen-based mechanism. Some studies in human populations suggest modulation by estrogens and some do not. The aggregate data point to minor constituents present in fiber, such as isoflavones and phytate as the biologically active components of fiber which may be responsible for its anti cancer effects.

  5. Boron nitride converted carbon fiber

    Science.gov (United States)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  6. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

  7. Principal modes in fiber amplifiers

    CERN Document Server

    Fridman, Moti; Dubinskii, Mark; Friesem, Asher A; Davidson, Nir

    2010-01-01

    The dynamics of the state of polarization in single mode and multimode fiber amplifiers are presented. The experimental results reveal that although the state of polarizations at the output can vary over a large range when changing the temperatures of the fiber amplifiers, the variations are significantly reduced when resorting to the principal states of polarization in single mode fiber amplifiers and principal modes in multimode fiber amplifiers.

  8. In-fiber integrated Michelson interferometer

    Science.gov (United States)

    Yuan, Libo; Yang, Jun; Liu, Zhihai; Sun, Jiaxing

    2006-09-01

    A novel fiber-optic in-fiber integrated Michelson interferometer has been proposed and demonstrated. It consists of a segment of two-core fiber with a mirrored fiber end. The sensing characteristics based on the two-core fiber bending, corresponding to the shift of the phase of the two-core in-fiber integrated Michelson interferometer, are investigated.

  9. In-fiber integrated Michelson interferometer.

    Science.gov (United States)

    Yuan, Libo; Yang, Jun; Liu, Zhihai; Sun, Jiaxing

    2006-09-15

    A novel fiber-optic in-fiber integrated Michelson interferometer has been proposed and demonstrated. It consists of a segment of two-core fiber with a mirrored fiber end. The sensing characteristics based on the two-core fiber bending, corresponding to the shift of the phase of the two-core in-fiber integrated Michelson interferometer, are investigated.

  10. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  11. Fabrication of Optical Fiber Devices

    Science.gov (United States)

    Andres, Miguel V.

    In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.

  12. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  13. Direct spinning of fiber supercapacitor.

    Science.gov (United States)

    Xu, Tong; Ding, Xiaoteng; Liang, Yuan; Zhao, Yang; Chen, Nan; Qu, Liangti

    2016-06-16

    A direct wet spinning approach is demonstrated for facile and continuous fabrication of a whole fiber supercapacitor using a microfluidic spinneret. The resulting fiber supercapacitor shows good electrochemical properties and possesses high flexibility and mechanical stability. This strategy paves the way for large-scale continuous production of fiber supercapacitors for weavable electronics.

  14. Drops spreading on flexible fibers

    Science.gov (United States)

    Somszor, Katarzyna; Boulogne, François; Sauret, Alban; Dressaire, Emilie; Stone, Howard

    2015-11-01

    Fibrous media are encountered in many engineered systems such as textile, paper and insulating materials. In most of these materials, fibers are randomly oriented and form a complex network in which drops of wetting liquid tend to accumulate at the nodes of the network. Here we investigate the role of the fiber flexibility on the spreading of a small volume of liquid on a pair of crossed flexible fibers. A drop of silicone oil is dispensed at the point of contact of the fibers and we characterize the liquid morphologies as we vary the volume of liquid, the angle between the fibers, and the length and bending modulus of the fibers. Drop morphologies previously reported for rigid fibers, i.e. a drop, a column and a mixed morphology, are also observed on flexible fibers with modified domains of existence. Moreover, at small inclination angles of the fibers, a new behavior is observed: the fibers bend and collapse. Depending on the volume, the liquid can adopt a column or a mixed morphology on the collapsed fibers. We rationalize our observations with a model based on energetic considerations. Our study suggests that the fiber flexibility adds a rich variety of behaviors that can be crucial for industrial applications.

  15. Neuroanatomic Fiber Orientation Maps (FOMs)

    DEFF Research Database (Denmark)

    Axer, Hubertus; Jantzen, Jan; Grässel, David

    2002-01-01

    A new neuroanatomic method is described which allows to map the orientation of central nervous fibers in gross histological sections. Polarised light is used to calculate the angle of inclination and direction of the fibers in each pixel. Serial fiber orientation maps (FOMs) can be aligned and 3D...

  16. Fiber Optics and Library Technology.

    Science.gov (United States)

    Koenig, Michael

    1984-01-01

    This article examines fiber optic technology, explains some of the key terminology, and speculates about the way fiber optics will change our world. Applications of fiber optics to library systems in three major areas--linkage of a number of mainframe computers, local area networks, and main trunk communications--are highlighted. (EJS)

  17. Buying Fiber-Optic Networks.

    Science.gov (United States)

    Fickes, Michael

    2003-01-01

    Describes consortia formed by college and university administrators to buy, manage, and maintain their own fiber-optic networks with the goals of cutting costs of leasing fiber-optic cable and planning for the future. Growth capacity is the real advantage of owning fiber-optic systems. (SLD)

  18. Shedding Light on Fiber Optics.

    Science.gov (United States)

    Bunch, Robert M.

    1994-01-01

    Explains the principles of fiber optics as a medium for light-wave communication. Current uses of fiber systems on college campuses include voice, video, and local area network applications. A group of seven school districts in Minnesota are linked via fiber-optic cables. Other uses are discussed. (MLF)

  19. Fiber-top micromachined devices

    NARCIS (Netherlands)

    Iannuzzi, D.; De Man, S.; Alberts, C.J.; Berenschot, Johan W.; Elwenspoek, Michael Curt; Said, A.A.; Dugan, M.

    2008-01-01

    After a general review on fiber-top technology, we will present our recent achievements in the utilization of fiber-top double-clamped cantilevers as refractometers and in the development of alternative techniques for the fabrication of fiber-top devices.

  20. Photonic-crystal fibers gyroscope

    Directory of Open Access Journals (Sweden)

    Ali Muse Haider

    2015-01-01

    Full Text Available In this paper we proposed to use of a photonic crystal fiber with an inner hollow defect. The use of such fibers is not affected by a material medium on the propagation of optical radiation. Photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications

  1. Aerogel-clad optical fiber

    Science.gov (United States)

    Sprehn, Gregory A.; Hrubesh, Lawrence W.; Poco, John F.; Sandler, Pamela H.

    1997-01-01

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency.

  2. Optical fibers for FTTH application

    Science.gov (United States)

    Guzowski, Bartlomiej; Tosik, Grzegorz; Lisik, Zbigniew; Bedyk, Michal; Kubiak, Andrzej

    2013-07-01

    In this paper the specifics of FTTH (Fiber To The Home) networks in terms of requirements for optical fibers has been presented. Optical fiber samples used in FTTH applications acquired from the worldwide leading manufacturers were subjected to small diameter mandrel wraps tests. The detailed procedures of performed tests and the measurement results has been presented.

  3. Syntheses of aliphatic polycarbonates from 2'-deoxyribonucleosides.

    Science.gov (United States)

    Suzuki, Masato; Sekido, Toyokazu; Matsuoka, Shin-ichi; Takagi, Koji

    2011-05-01

    Poly(2'-deoxyadenosine) and poly(thymidine) constructed of carbonate linkages were synthesized by polycondensation between silyl ether and carbonylimidazolide at the 3'- and 5'-positions of the 2'-deoxyribonucleoside monomers. The N-benzoyl-2'-deoxyadenosine monomer afforded the corresponding polycarbonate together with the cyclic oligomers. However, the deprotection of the N-benzoyl group resulted in the scission of the polymer main chain. Thus, the N-unprotected 2'-deoxyadenosine monomers were examined for polycondensation. However, there was involved the undesired reaction between the adenine amino group and the carbonylimidazolide to form the carbamate linkage. In order to exclude this unfavorable reaction, dynamic protection was employed. Strong hydrogen bonding was used in place of the usual covalent bonding for reducing the nucleophilicity of the adenine amino group. Herein, 3',5'-O-diacylthymidines that form the complementary hydrogen bonding with the adenine amino group were added to the polymerization system of the N-unprotected 2'-deoxyadenosine monomer. Consequently, although the oligomers (M(n) = 1000-1500) were produced, the contents of the carbamate group were greatly reduced. The dynamic protection reagents were easily and quantitatively recovered as the MeOH soluble parts from the polymerization mixtures. In the polycondensation of the thymidine monomer, there tended to be involved another unfavorable reaction of carbonate exchange, which consequently formed the irregular carbonate linkages at not only the 3'-5' but also the 3'-3' and 5'-5' positions. Employing the well-designed monomer suppressed the carbonate exchange reaction to produce poly(thymidine) with the almost regular 3'-5'carbonate linkages.

  4. Optical fiber sensors measurement system and special fibers improvement

    Science.gov (United States)

    Jelinek, Michal; Hrabina, Jan; Hola, Miroslava; Hucl, Vaclav; Cizek, Martin; Rerucha, Simon; Lazar, Josef; Mikel, Bretislav

    2017-06-01

    We present method for the improvement of the measurement accuracy in the optical frequency spectra measurements based on tunable optical filters. The optical filter was used during the design and realization of the measurement system for the inspection of the fiber Bragg gratings. The system incorporates a reference block for the compensation of environmental influences, an interferometric verification subsystem and a PC - based control software implemented in LabView. The preliminary experimental verification of the measurement principle and the measurement system functionality were carried out on a testing rig with a specially prepared concrete console in the UJV Řež. The presented system is the laboratory version of the special nuclear power plant containment shape deformation measurement system which was installed in the power plant Temelin during last year. On the base of this research we started with preparation other optical fiber sensors to nuclear power plants measurement. These sensors will be based on the microstructured and polarization maintaining optical fibers. We started with development of new methods and techniques of the splicing and shaping optical fibers. We are able to made optical tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters. We developed new techniques of splicing standard Single Mode (SM) and Multimode (MM) optical fibers and splicing of optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with development these techniques we prepared other techniques to splicing and shaping special optical fibers like as Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard telecommunication and other SM fibers can be done by our developed techniques. Adjustment

  5. Aminosilane-grafted polymer/silica hollow fiber adsorbents for CO₂ capture from flue gas.

    Science.gov (United States)

    Rezaei, Fateme; Lively, Ryan P; Labreche, Ying; Chen, Grace; Fan, Yanfang; Koros, William J; Jones, Christopher W

    2013-05-01

    sharp CO2 front for APS-grafted fibers, indicating fast kinetics with comparable pseudo-equilibrium capacities to the CO2 equilibrium capacities measured via thermogravimetric analysis (TGA). The results indicate the post-spinning infusion method provides a new platform for synthesizing composite polymer/silica/amine fibers that may facilitate the ultimate scale-up of practical fiber adsorbents for flue gas CO2 capture applications.

  6. Fiber reinforced silicon-containing arylacetylene resin composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available A silicon-containing arylacetylene resin (SAR, a poly(dimethylsilyleneethynylene phenyleneethynylene (PMSEPE, was synthesized. The PMSEPE is a solid resin at ambient temperature with a softening temperature about 60°C and soluble in some solvents like tetrahydrofuran. The melt viscosity of the PMSEPE resin is less than 1 Pa•s. The resin could cure at the temperature of lower than 200°C. Fiber reinforced PMSEPE composites were prepared from prepregs which were made by the impregnation of fibers in PMSEPE resin solution. The composites exhibit good mechanical properties at room temperature and 250°C. The observation on fracture surfaces of the composites reinforced by glass fibers and carbon fibers demonstrates that the adhesion between the fibers and resin is good. The results from an oxyacetylene flame test show that the composites have good ablation performance and XRD analyses indicate that SiC forms in the residues during the ablation of the composites.

  7. Interferometric Fiber Optic Sensors

    Directory of Open Access Journals (Sweden)

    Hae Young Choi

    2012-02-01

    Full Text Available Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair.

  8. Interferometric fiber optic sensors.

    Science.gov (United States)

    Lee, Byeong Ha; Kim, Young Ho; Park, Kwan Seob; Eom, Joo Beom; Kim, Myoung Jin; Rho, Byung Sup; Choi, Hae Young

    2012-01-01

    Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG) is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair.

  9. High Power Fiber Lasers

    Science.gov (United States)

    2012-08-02

    Optics, Information and Photonics, University of Erlangen- Nuremberg , Germany, June 2007. INVITED 14. A. Siegman, “Index Antiguided Optical Fibers and...Lasers” seminar given at the Institute for Optics, Information and Photonics, University of Erlangen- Nuremberg , Germany, June 2007. INVITED 14. A

  10. Bluebonnet Fiber Collages

    Science.gov (United States)

    Sterling, Joan

    2009-01-01

    This article presents a lesson that uses stitching and applique techniques to create a fiber collage in which every child is successful with high-quality work. This lesson was inspired by Tomie dePaola's "The Legend of the Bluebonnet." The back cover had a lovely illustration of the bluebonnet flower the author thought would translate easily to a…

  11. Infrared Fiber Optic Sensors

    Science.gov (United States)

    1997-01-01

    Successive years of Small Business Innovation Research (SBIR) contracts from Langley Research Center to Sensiv Inc., a joint venture between Foster-Miller Inc. and Isorad, Ltd., assisted in the creation of remote fiber optic sensing systems. NASA's SBIR interest in infrared, fiber optic sensor technology was geared to monitoring the curing cycles of advanced composite materials. These funds helped in the fabrication of an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. Foster-Miller ingenuity allowed infrared transmitting optical fibers to combine with Fourier Transform Infrared spectroscopy to enable remote sensing. Sensiv probes operate in the mid-infrared range of the spectrum, although modifications to the instrument also permits its use in the near-infrared region. The Sensiv needle-probe is built to be placed in a liquid or powder and analyze the chemicals in the mixture. Other applications of the probe system include food processing control; combustion control in furnaces; and maintenance problem solving.

  12. Funky inorganic fibers

    NARCIS (Netherlands)

    de Wit, Patrick

    2017-01-01

    Inorganic porous hollow fibers (IPHF) are interesting for various applications that can benefit from a high surface-area-to-volume ratio. Examples include membranes, catalysts, electrodes, and combinations of these. The thesis starts with providing an overview of conceivable materials of which IPHF

  13. Optical Fiber Protection

    Science.gov (United States)

    1999-01-01

    F&S Inc. developed and commercialized fiber optic and microelectromechanical systems- (MEMS) based instrumentation for harsh environments encountered in the aerospace industry. The NASA SBIR programs have provided F&S the funds and the technology to develop ruggedized coatings and coating techniques that are applied during the optical fiber draw process. The F&S optical fiber fabrication facility and developed coating methods enable F&S to manufacture specialty optical fiber with custom designed refractive index profiles and protective or active coatings. F&S has demonstrated sputtered coatings using metals and ceramics and combinations of each, and has also developed techniques to apply thin coatings of specialized polyimides formulated at NASA Langley Research Center. With these capabilities, F&S has produced cost-effective, reliable instrumentation and sensors capable of withstanding temperatures up to 800? C and continues building commercial sales with corporate partners and private funding. More recently, F&S has adapted the same sensing platforms to provide the rapid detection and identification of chemical and biological agents

  14. Optical Fiber Spectroscopy

    Science.gov (United States)

    Buoncristiani, A. M.

    1999-01-01

    This is the final report of work done on NASA Grant NAG-1-443. The work covers the period from July 1, 1992 to December 1, 1998. During this period several distinct but related research studies and work tasks were undertaken. These different subjects are enumerated below with a description of the work done on each of them. The focus of the research was the development of optical fibers for use as distributed temperature and stress sensors. The initial concept was to utilize the utilize the temperature and stress dependence of emission from rare earth and transition metal ions substitutionally doped into crystalline or glass fibers. During the course of investigating this it became clear that fiber Bragg gratings provided a alternative for making the desired measurements and there was a shift of research focus on to include the photo-refractive properties of germano-silicate glasses used for most gratings and to the possibility of developing fiber laser sources for an integrated optical sensor in the research effort. During the course of this work several students from Christopher Newport University and other universities participated in this effort. Their names are listed below. Their participation was an important part of their education.

  15. Fiber-diffraction Interferometer using Coherent Fiber Optic Taper

    CERN Document Server

    Kihm, Hagyong

    2010-01-01

    We present a fiber-diffraction interferometer using a coherent fiber optic taper for optical testing in an uncontrolled environment. We use a coherent fiber optic taper and a single-mode fiber having thermally-expanded core. Part of the measurement wave coming from a test target is condensed through a fiber optic taper and spatially filtered from a single-mode fiber to be reference wave. Vibration of the cavity between the target and the interferometer probe is common to both reference and measurement waves, thus the interference fringe is stabilized in an optical way. Generation of the reference wave is stable even with the target movement. Focus shift of the input measurement wave is desensitized by a coherent fiber optic taper.

  16. Fiber Bragg filters For laser- and multicore fibers

    Science.gov (United States)

    Becker, Martin; Elsmann, Tino; Lorenz, Adrian; Rothhardt, Manfred

    2017-05-01

    Fiber Bragg gratings (FBGs) have widespread applications in security, information, structural health monitoring, and biophotonics. In telecom applications, FBG inscription has reached a high level of maturity, but remains mainly limited to germanium doped photosensitive single mode fibers. Special applications, like filtering in light harvesting fibers or resonator mirrors for fiber lasers have to deal with special aspects which make the design and realization of FBGs a challenging task. One aspect is the extended wavelength range of these applications. Another aspect is the increasing demand to inscribe fiber Bragg gratings in non-photosensitive germanium-free fibers. Therefore, novel concepts of photosensitivity are proposed. Finally, to increase the amount of captured light the size of the fiber core and the numerical aperture have also to be increased. This goes along with multimode operation and prevents good filtering properties of Bragg gratings.

  17. Polymer-Derived Ceramic Fibers

    Science.gov (United States)

    Ichikawa, Hiroshi

    2016-07-01

    SiC-based ceramic fibers are derived from polycarbosilane or polymetallocarbosilane precursors and are classified into three groups according to their chemical composition, oxygen content, and C/Si atomic ratio. The first-generation fibers are Si-C-O (Nicalon) fibers and Si-Ti-C-O (Tyranno Lox M) fibers. Both fibers contain more than 10-wt% oxygen owing to oxidation during curing and lead to degradation in strength at temperatures exceeding 1,300°C. The maximum use temperature is 1,100°C. The second-generation fibers are SiC (Hi-Nicalon) fibers and Si-Zr-C-O (Tyranno ZMI) fibers. The oxygen content of these fibers is reduced to less than 1 wt% by electron beam irradiation curing in He. The thermal stability of these fibers is improved (they are stable up to 1,500°C), but their creep resistance is limited to a maximum of 1,150°C because their C/Si atomic ratio results in excess carbon. The third-generation fibers are stoichiometric SiC fibers, i.e., Hi-Nicalon Type S (hereafter Type S), Tyranno SA, and Sylramic™ fibers. They exhibit improved thermal stability and creep resistance up to 1,400°C. Stoichiometric SiC fibers meet many of the requirements for the use of ceramic matrix composites for high-temperature structural application. SiBN3C fibers derived from polyborosilazane also show promise for structural applications, remain in the amorphous state up to 1,800°C, and have good high-temperature creep resistance.

  18. Health Benefits of Fiber Fermentation.

    Science.gov (United States)

    Dahl, Wendy J; Agro, Nicole C; Eliasson, Åsa M; Mialki, Kaley L; Olivera, Joseph D; Rusch, Carley T; Young, Carly N

    2017-02-01

    Although fiber is well recognized for its effect on laxation, increasing evidence supports the role of fiber in the prevention and treatment of chronic disease. The aim of this review is to provide an overview of the health benefits of fiber and its fermentation, and describe how the products of fermentation may influence disease risk and treatment. Higher fiber intakes are associated with decreased risk of cardiovascular disease, type 2 diabetes, and some forms of cancer. Fiber may also have a role in lowering blood pressure and in preventing obesity by limiting weight gain. Fiber is effective in managing blood glucose in type 2 diabetes, useful for weight loss, and may provide therapeutic adjunctive roles in kidney and liver disease. In addition, higher fiber diets are not contraindicated in inflammatory bowel disease or irritable bowel syndrome and may provide some benefit. Common to the associations with disease reduction is fermentation of fiber and its potential to modulate microbiota and its activities and inflammation, specifically the production of anti-inflammatory short chain fatty acids, primarily from saccharolytic fermentation, versus the deleterious products of proteolytic activity. Because fiber intake is inversely associated with all-cause mortality, mechanisms by which fiber may reduce chronic disease risk and provide therapeutic benefit to those with chronic disease need further elucidation and large, randomized controlled trials are needed to confirm causality.Teaching Points• Strong evidence supports the association between higher fiber diets and reduced risk of cardiovascular disease, type 2 diabetes, and some forms of cancer.• Higher fiber intakes are associated with lower body weight and body mass index, and some types of fiber may facilitate weight loss.• Fiber is recommended as an adjunctive medical nutritional therapy for type 2 diabetes, chronic kidney disease, and certain liver diseases.• Fermentation and the resulting shifts in

  19. Continuous Carbon Nanotube-Based Fibers and Films for Applications Requiring Enhanced Heat Dissipation.

    Science.gov (United States)

    Liu, Peng; Fan, Zeng; Mikhalchan, Anastasiia; Tran, Thang Q; Jewell, Daniel; Duong, Hai M; Marconnet, Amy M

    2016-07-13

    The production of continuous carbon nanotube (CNT) fibers and films has paved the way to leverage the superior properties of individual carbon nanotubes for novel macroscale applications such as electronic cables and multifunctional composites. In this manuscript, we synthesize fibers and films from CNT aerogels that are continuously grown by floating catalyst chemical vapor deposition (FCCVD) and measure thermal conductivity and natural convective heat transfer coefficient from the fiber and film. To probe the mechanisms of heat transfer, we develop a new, robust, steady-state thermal characterization technique that enables measurement of the intrinsic fiber thermal conductivity and the convective heat transfer coefficient from the fiber to the surrounding air. The thermal conductivity of the as-prepared fiber ranges from 4.7 ± 0.3 to 28.0 ± 2.4 W m(-1) K(-1) and depends on fiber volume fraction and diameter. A simple nitric acid treatment increases the thermal conductivity by as much as a factor of ∼3 for the fibers and ∼6.7 for the thin films. These acid-treated CNT materials demonstrate specific thermal conductivities significantly higher than common metals with the same absolute thermal conductivity, which means they are comparatively lightweight, thermally conductive fibers and films. Beyond thermal conductivity, the acid treatment enhances electrical conductivity by a factor of ∼2.3. Further, the measured convective heat transfer coefficients range from 25 to 200 W m(-2) K(-1) for all fibers, which is higher than expected for macroscale materials and demonstrates the impact of the nanoscale CNT features on convective heat losses from the fibers. The measured thermal and electrical performance demonstrates the promise for using these fibers and films in macroscale applications requiring effective heat dissipation.

  20. Flexible Fiber-Shaped Supercapacitor Based on Nickel-Cobalt Double Hydroxide and Pen Ink Electrodes on Metallized Carbon Fiber.

    Science.gov (United States)

    Gao, Libo; Surjadi, James Utama; Cao, Ke; Zhang, Hongti; Li, Peifeng; Xu, Shang; Jiang, Chenchen; Song, Jian; Sun, Dong; Lu, Yang

    2017-02-15

    Flexible fiber-shaped supercapacitors (FSSCs) are recently of extensive interest for portable and wearable electronic gadgets. Yet the lack of industrial-scale flexible fibers with high conductivity and capacitance and low cost greatly limits its practical engineering applications. To this end, we here present pristine twisted carbon fibers (CFs) coated with a thin metallic layer via electroless deposition route, which exhibits exceptional conductivity with ∼300% enhancement and superior mechanical strength (∼1.8 GPa). Subsequently, the commercially available conductive pen ink modified high conductive composite fibers, on which uniformly covered ultrathin nickel-cobalt double hydroxides (Ni-Co DHs) were introduced to fabricate flexible FSSCs. The synthesized functionalized hierarchical flexible fibers exhibit high specific capacitance up to 1.39 F·cm(-2) in KOH aqueous electrolyte. The asymmetric solid-state FSSCs show maximum specific capacitance of 28.67 mF·cm(-2) and energy density of 9.57 μWh·cm(-2) at corresponding power density as high as 492.17 μW·cm(-2) in PVA/KOH gel electrolyte, with demonstrated high flexibility during stretching, demonstrating their potential in flexible electronic devices and wearable energy systems.

  1. Synthesis of silver nanoparticles in textile finish aqueous system and their antimicrobial properties on cotton fibers

    Science.gov (United States)

    Silver nanoparticles (NPs) were synthesized by a simple and environmentally benign procedure using poly (ethylene glycol) (PEG) as reducing agent and stabilizer in the textile finish aqueous system, and their antimicrobial properties on greige (mechanically cleaned) and bleached cotton fibers were i...

  2. Sinapate dehydrodimers and sinapate−ferulate heterodimers in cereal dietary fiber

    Science.gov (United States)

    Mirko Bunzel; John Ralph; Hoon Kim; Fachuang Lu; Sally A. Ralph; Jane M. Marita; Ronald D. Hatfield; Hans Steinhart

    2003-01-01

    Two 8-8-coupled sinapic acid dehydrodimers and at least three sinapate-ferulate heterodimers have been identified as saponification products from different insoluble and soluble cereal grain dietary fibers. The two 8-8-disinapates were authenticated by comparison of their GC retention times and mass spectra with authentic dehydrodimers synthesized from methyl or ethyl...

  3. Synthesis of porous carbon fibers with strong anion exchange functional groups.

    Science.gov (United States)

    Zheng, Weihua; Hu, Jingtian; Han, Zheshen; Wang, Zixing; Zheng, Zhen; Langer, James; Economy, James

    2015-06-18

    Hybrid porous carbon fibers with strong anion-exchangeable functional groups (HACAX) were synthesized by alkylation of pyrolyzed polyacrylonitrile. HACAX exhibits generic stable positively charged functional groups. This expands the applications of porous carbon media for interacting with anions without adjusting pH, such as Cr(vi) adsorption at natural pH.

  4. Multimetallic Electrodeposition on Carbon Fibers

    Science.gov (United States)

    Böttger-Hiller, F.; Kleiber, J.; Böttger, T.; Lampke, T.

    2016-03-01

    Efficient lightweight design requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon fiber reinforced plastics (CFRP) by plating the fiber component. Electroplating leads to metalized layers on carbon fibers. Herein only cyanide-free electrolytes where used. Until now dendrite-free layers were only obtained using current densities below 1.0 A dm-2. In this work, dendrite-free tin and copper coatings were achieved by pre-metalizing the carbon fiber substrates. Furthermore, applying a combination of two metals with different sized thermal expansion coefficient lead to a bimetallic coating on carbon fiber rovings, which show an actuatory effect.

  5. Transmission Properties of Fiber Probes

    Institute of Scientific and Technical Information of China (English)

    XUE Chun-rong; ZHU Sheng-xiang; XIAO Zhi-gang

    2004-01-01

    Transmission properties of tapered fiber including right cone fiber and bend optical fiber are discussed. The transmission efficiency of the tapered fiber is measured. The curve of transmission efficiency versus taper cone angle is given. By the scalar wave equation and Gaussian approximation, transmission properties of the two kinds of tapered fibers are analyzed, the power losses caused by taper cone angle and by the bending are also calculated. From the experiments and theoretical analysis, it could come to a conclusion that the wider the taper cone angle is, the higher the transmission efficiency will be.

  6. Ground Wood Fiber Length Distributions

    Directory of Open Access Journals (Sweden)

    Lauri Ilmari Salminen

    2014-01-01

    Full Text Available This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results.

  7. Optical-Fiber Leak Detector

    Science.gov (United States)

    Workman, Gary L.; Kosten, Susan E.

    1994-01-01

    Proposed optical-fiber sensor detects small changes in pressure in elastomeric O-ring or similar pressure seal, which may indicate deterioration of seal and interpreted as indications of incipient failure. According to concept, length of optical fiber embedded in seal. Light-emitting diode illuminates one end of fiber; photodetector measures intensity of light emerging from other end. Pressure-induced changes in seal bend fiber slightly, altering microbending-induced loss of light from fiber and alter intensity of light at photodetector. Change in intensity approximately proportional to change in pressure.

  8. Syntheses and electronic structures of decamethylmetallocenes

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, J.L.

    1981-04-01

    The synthesis of decamethylmanganocene ((eta-C/sub 5/(CH/sub 3/)/sub 5/)/sub 2/Mn or (Me/sub 5/Cp)/sub 2/Mn)) is described. Magnetic susceptibility and electron paramagnetic resonance (EPR) studies show that (Me/sub 5/Cp)/sub 2/Mn is a low-spin, 17-electron compound with an orbitally degenerate, /sup 2/E/sub 2g/ (e/sub 2g//sup 3/ a/sub 1g//sup 2/) ground state. An x-ray crystallographic study of (Me/sub 5/Cp)/sub 2/Mn shows that it is a monomeric, D/sub 5d/ decamethylmetallocene with metal to ring carbon distances that are about 0.3 A shorter than those determined for high-spin manganocenes. The syntheses of new (Me/sub 5/Cp)/sub 2/M (M = Mg,V,Cr,Co, and Ni) and ((Me/sub 5/Cp)/sub 2/M)PF/sub 6/ (M = Cr,Co, and Ni) compounds are described. In addition, a preparative route to a novel, dicationic decamethylmetallocene, ((Me/sub 5/Cp)/sub 2/Ni)(PF/sub 6/)/sub 2/ is reported. Infrared, nuclear magnetic resonance, magnetic susceptibility, and/or x-ray crystallographic studies indicate that all the above compounds are D/sub 5d/ or D/sub 5h/ decamethylmetallocenes with low-spin electronic configurations. Cyclic voltammetry studies verify the reversibility and the one-electron nature of the (Me/sub 5/Cp)/sub 2/M ..-->.. ((Me/sub 5/Cp)/sub 2/M)/sup +/ (M = Cr,Mn,Fe,Co,Ni), ((Me/sub 5/Cp)/sub 2/Mn)/sup -/ ..-->.. (Me/sub 5/Cp)/sub 2/Mn and ((Me/sub 5/Cp)/sub 2/Ni)/sup +/ ..-->.. (Me/sub 5/Cp)/sub 2/Ni)/sup 2 +/ redox reactions. These studies reveal that the neutral decamethylmetallocenes are much more easily oxidized than their metallocene counterparts. This result attests to the electron-donating properties of the ten substituent methyl groups. Proton and carbon-13 NMR data are reported for the diamagnetic Mg(II), Mn(I), Fe(II), Co(III), and Ni(IV) decamethylmetallocenes and for ((Me/sub 5/Cp)/sub 2/V(CO)/sub 2/)/sup +/. The uv-visible absorption spectra of the 15-, 18- and 20- electron decamethylmetallocenes are also reported.

  9. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

    OpenAIRE

    Weimin Song; Jian Yin

    2016-01-01

    Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%,...

  10. Lignin-based active anode materials synthesized from low-cost renewable resources

    Energy Technology Data Exchange (ETDEWEB)

    Rios, Orlando; Tenhaeff, Wyatt Evan; Daniel, Claus; Dudney, Nancy Johnston; Johs, Alexander; Nunnery, Grady Alexander; Baker, Frederick Stanley

    2016-06-07

    A method of making an anode includes the steps of providing fibers from a carbonaceous precursor, the carbon fibers having a glass transition temperature T.sub.g. In one aspect the carbonaceous precursor is lignin. The carbonaceous fibers are placed into a layered fiber mat. The fiber mat is fused by heating the fiber mat in the presence of oxygen to above the T.sub.g but no more than 20% above the T.sub.g to fuse fibers together at fiber to fiber contact points and without melting the bulk fiber mat to create a fused fiber mat through oxidative stabilization. The fused fiber mat is carbonized by heating the fused fiber mat to at least 650.degree. C. under an inert atmosphere to create a carbonized fused fiber mat. A battery anode formed from carbonaceous precursor fibers is also disclosed.

  11. MM-wave synthesizer has 8-to-15-GHz bandwidth

    Science.gov (United States)

    Fortunato, M. P.; Ishikawa, K. Y.

    1982-05-01

    Millimeter-wave sweeper IMPATT diodes are combined with microprocessor control and opamp circuitry to give a fast and accurate W-band synthesizer. The breakthrough in millimeter-wave frequency synthesizer development derives from the ability to lock virtually any millimeter-wave IMPATT. The considerable improvement in SSB phase noise of a phase-locked sweeper IMPATT versus a free-running Gunn, fixed-tuned IMPATT, and free-running sweeper IMPATT is illustrated. The spectra of a free-running and a phase-locked sweeper IMPATT are compared. A block diagram of the complete millimeter-wave synthesizer is included, together with typical W-band synthesizer specifications.

  12. Muscle Fiber Conduction Velocity, Muscle Fiber Composition, and Power Performance.

    Science.gov (United States)

    Methenitis, Spyridon; Karandreas, Nikolaos; Spengos, Konstantinos; Zaras, Nikolaos; Stasinaki, Angeliki-Nikoletta; Terzis, Gerasimos

    2016-09-01

    The aim of this study was to explore the relationship between muscle fiber conduction velocity (MFCV), fiber type composition, and power performance in participants with different training background. Thirty-eight young males with different training background participated: sedentary (n = 10), endurance runners (n = 9), power trained (n = 10), and strength trained (n = 9). They performed maximal countermovement jumps (CMJ) and maximal isometric leg press for the measurement of the rate of force development (RFD). Resting vastus lateralis MFCV was measured with intramuscular microelectrodes on a different occasion, whereas muscle fiber type and cross-sectional area (CSA) of vastus lateralis were evaluated through muscle biopsies 1wk later. MFCV, CMJ power, RFD, and % CSA of type II and type IIx fibers were higher for the power-trained group (P power participants. Close correlations were found between MFCV and fiber CSA as well as the % CSA of all fiber types as well as with RFD and CMJ power (r = 0.712-0.943, P power performance. Significant models for the prediction of the % CSA of type IIa and type II as well as the CSA of all muscle fibers based upon MFCV, RFD, and CMJ were revealed (P = 0.000). MFCV is closely associated with muscle fiber % CSA. RFD and jumping power are associated with the propagation of the action potentials along the muscle fibers. This link is regulated by the size and the distribution of type II, and especially type IIx muscle fibers.

  13. Fabrication and characterization of functionally graded poly(vinylidine fluoride)-silver nanocomposite hollow fibers for sustainable water recovery

    KAUST Repository

    Francis, Lijo

    2014-12-01

    Poly(vinylidine fluoride) (PVDF) asymmetric hydrophobic hollow fibers were fabricated successfully using dryjet wet spinning. Hydrophobic silver nanoparticles were synthesized and impregnated into the PVDF polymer matrix and functionally graded PVDF-silver nanocomposite hollow fibers are fabricated and tested in the direct contact membrane distillation (DCMD) process. The as-synthesized silver nanoparticles were characterized for Transmission Electron Microscopy (TEM), particle size distribution (PSD) and Ultra Violet (UV) visible spectroscopy. Both the PVDF and PVDF-silver nanocomposite asymmetric hollow fibers were characterized for their morphology, water contact angle and mechanical strength. Addition of hydrophobic silver nanoparticles was found to enhance the hydrophobicity and ~ 2.5 fold increase the mechanical strength of the hollow fibers. A water vapor flux of 31.9kg m-2 h-1 was observed at a feed inlet temperature of 80 °C and at a permeate temperature of 20 °C in the case of hollow fiber membrane modules fabricated using PVDF hollow fibers; the water vapor flux was found to be increased by about 8% and to reach 34.6kg m-2 h-1 for the hollow fiber membrane modules fabricated from the PVDF-silver nanocomposite hollow fibers at the same operating conditions with 99.99% salt rejection.

  14. Graphene quantum dots derived from carbon fibers.

    Science.gov (United States)

    Peng, Juan; Gao, Wei; Gupta, Bipin Kumar; Liu, Zheng; Romero-Aburto, Rebeca; Ge, Liehui; Song, Li; Alemany, Lawrence B; Zhan, Xiaobo; Gao, Guanhui; Vithayathil, Sajna Antony; Kaipparettu, Benny Abraham; Marti, Angel A; Hayashi, Takuya; Zhu, Jun-Jie; Ajayan, Pulickel M

    2012-02-08

    Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications.

  15. Electro-magnetic properties of composites with aligned Fe-Co hollow fibers

    Directory of Open Access Journals (Sweden)

    Seungchan Cho

    2016-05-01

    Full Text Available A novel Fe-Co binary hollow fiber was synthesized by electroless plating using hydrolyzed polyester fiber and its anisotropy characteristic was investigated for electromagnetic wave absorbing materials. The hollow fibers in parallel with magnetic field show higher saturated magnetization of 202 emu/g at the applied magnetic field of 10 kOe and lower coercivity (27.658 Oe, compared with the random and vertical oriented hollow fibers. From complex permittivity measurement, the Fe-Co hollow fiber composites clearly display a single dielectric resonance, located at ∼14 GHz. The Fe-Co hollow fibers not only provide excellent EM properties in GHz frequency ranges, resulting mainly from the strong resonance, but also adjust the soft magnetic properties through fiber alignments. The cavitary structure of the Fe-Co hollow fibers, not only giving rise to a dielectric loss resonance and also adjusting its peak frequency, may be a pathway to useful EM wave absorptive devices in GHz frequency ranges.

  16. Synthesis and Properties of Poly[p-(2,5-dihydroxy- phenylenebenzobisoxazole] Fiber

    Directory of Open Access Journals (Sweden)

    Hong Lin

    2008-11-01

    Full Text Available The novel polymer poly[p-(2,5-dihydroxy-phenylenebenzobisoxazole] (PBOH fiber was synthesized in the presence of 2,5-dihydroxyterephthalicacid (DHTA and 4,6-diamino-1,3-benzenediol in poly(phosphoric acid (PPA using typical polycondensation conditions. The crystalline solutions of liquid PBOH in PPA were spun into fibers using dry-jet wet spinning. Furthermore, the thermostability and mechanical properties of PBOH were compared with poly(p-phenylene-2,6-benzoxazole (PBO in order to investigate the relationship between the chain structure and properties. The results indicated that the thermal degradation temperature of PBOH was above 750K and the tensile strength of the PBOH fiber was 3.1GPa, which were much lower than those of PBO fiber. The compressive strength of PBOH fiber was 331 M Pa, which was slightly higher than that of PBO fiber. In addition, molecular simulation was employed to explain why the compressive strength of PBOH fiber did not increase significantly compared to PBO fiber.

  17. Dietary Fiber Future Directions: Integrating New Definitions and Findings to Inform Nutrition Research and Communication12

    Science.gov (United States)

    Jones, Julie Miller

    2013-01-01

    The CODEX Alimentarius definition of dietary fiber includes all nondigestible carbohydrate polymers with a degree of polymerization of 3 or more as dietary fiber with the proviso that they show health benefits. The global definition, if accepted by all authoritative bodies, offers a chance for international harmonization in research, food composition tables, and food labeling. Its nonacceptance highlights problems that may develop when definitions vary by region. The definition requires that the research community agrees upon physiological effects for which there is substantial scientific agreement, e.g., fibers’ effects on laxation and gut health, on attenuating blood lipids and blood glucose and insulin, and in promoting fermentation in the large bowel. The definition also necessitates the delineation of research protocols to prove the benefits of various isolated and synthesized fibers. These should emanate from evidence-based reviews that fairly weigh epidemiological data while considering that added fibers are not reflected in many food composition databases. They then should include well-controlled, randomized, control trials and utilize animal studies to determine mechanisms. Agreement on many study variables such as the type of subject and the type of baseline diet that best fits the question under investigation will also be needed. Finally, the definition establishes that all types of fiber can address the severe fiber consumption gap that exists throughout the world by recognizing that the combination of fiber-rich and -fortified foods increases fiber intake while allowing consumers to stay within allowed energy levels. PMID:23319118

  18. Fiber formation of a synthetic spider peptide derived from Nephila clavata.

    Science.gov (United States)

    Hidaka, Yuji; Kontani, Ko-Ichi; Taniguchi, Rina; Saiki, Masatoshi; Yokoi, Sayoko; Yukuhiro, Kenji; Yamaguchi, Hiroshi; Miyazawa, Mitsuhiro

    2011-01-01

    Dragline silk is a high-performance biopolymer with exceptional mechanical properties. Artificial spider dragline silk is currently prepared by a recombinant technique or chemical synthesis. However, the recombinant process is costly and large-sized synthetic peptides are needed for fiber formation. In addition, the silk fibers that are produced are much weaker than a fiber derived from a native spider. In this study, a small peptide was chemically synthesized and examined for its ability to participate in fiber formation. A short synthetic peptide derived from Nephila clavata was prepared by a solid-phase peptide method, based on a prediction using the hydrophobic parameter of each individual amino acid residue. After purification of the spider peptide, fiber formation was examined under several conditions. Fiber formation proceeded in the acidic pH range, and larger fibers were produced when organic solvents such as trifluoroethanol and acetonitrile were used at an acidic pH. Circular dichroism measurements of the spider peptide indicate that the peptide has a beta-sheet structure and that the formation of a beta-sheet structure is required for the spider peptide to undergo fiber formation.

  19. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

  20. Optical fiber communications

    CERN Document Server

    Keiser, Gerd

    2008-01-01

    The fourth edition of this popular text and reference book presents the fundamental principles for understanding and applying optical fiber technology to sophisticated modern telecommunication systems. Optical-fiber-based telecommunication networks have become a major information-transmission-system, with high capacity links encircling the globe in both terrestrial and undersea installations. Numerous passive and active optical devices within these links perform complex transmission and networking functions in the optical domain, such as signal amplification, restoration, routing, and switching. Along with the need to understand the functions of these devices comes the necessity to measure both component and network performance, and to model and stimulate the complex behavior of reliable high-capacity networks.

  1. Fiber-reinforced ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Belcheva, D. [Technological University `Prof. A. Zlatarov`, Bourgas (Bulgaria); Lubchev, L.; Jelezkov, G.; Georgiev, W.

    1995-03-01

    The possibilities for preparation of reinforced composite materials were studied. Test specimens based on different types of alumina matrices, plasticized with formaldehyde oligomer and polyvinyl alcohol, and reinforced with carbon and mullite fibers were prepared and investigated. The results confirmed that reinforced composite materials with valuable properties such as high thermal shock resistance, chemical resistance and mechanical strength can be produced. The density of technical alumina materials is lower, compared with that of pure alumina. The density can also be influenced by the type and quantity of the plasticizers used. By increasing the fiber content, the density of the material decreases. The shrinkage is influcenced by the type and the quantity of the reinforcing material. (orig.)

  2. Fiber optic geophysical sensors

    Science.gov (United States)

    Homuth, Emil F.

    1991-01-01

    A fiber optic geophysical sensor in which laser light is passed through a sensor interferometer in contact with a geophysical event, and a reference interferometer not in contact with the geophysical event but in the same general environment as the sensor interferometer. In one embodiment, a single tunable laser provides the laser light. In another embodiment, separate tunable lasers are used for the sensor and reference interferometers. The invention can find such uses as monitoring for earthquakes, and the weighing of objects.

  3. Infrared Fiber Optics.

    Science.gov (United States)

    1979-12-01

    solid lubricants (anthacene, p-terphenyl). To date, the best lubricants have been Parafilm and beeswax . Using these materials to coat the KC1 billets...fabrication involves both extruding KCl fibers and also preparing the starting billet used in the extrusion. The billets are then usually coated with a...8217C) and be removable after extrusion. This has limited the choice of lubricants to waxes (parafin, beeswax ), polyethelene mixtures (Parafilm M), and

  4. Fiber reinforced polypropylene nanocomposites

    OpenAIRE

    2007-01-01

    The aim of this thesis is to assess the feasibility of integrating nanoparticles into glass fiber (GF) reinforced isotactic polypropylene (iPP) composites via existing thermoplastic processing routes, and to investigate whether this results in significant improvements in the mechanical properties of the final composites. A longer term aim will be to extend the approach to the preparation of hybrid composites with added non-structural functionality. However, the nanoparticles that have provide...

  5. Fiber reinforced polypropylene nanocomposites

    OpenAIRE

    2008-01-01

    The aim of this thesis is to assess the feasibility of integrating nanoparticles into glass fiber (GF) reinforced isotactic polypropylene (iPP) composites via existing thermoplastic processing routes, and to investigate whether this results in significant improvements in the mechanical properties of the final composites. A longer term aim will be to extend the approach to the preparation of hybrid composites with added non-structural functionality. However, the nanoparticles that have provide...

  6. Homogenization of long fiber reinforced composites including fiber bending effects

    Science.gov (United States)

    Poulios, Konstantinos; Niordson, Christian F.

    2016-09-01

    This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows to maintain the kinematics of the two material phases independent from the assumed constitutive models, so that stress-deformation relationships, can be expressed in the framework of hyper-elasticity and hyper-elastoplasticity for the fiber and the matrix materials respectively. The bending stiffness of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization of the matrix and the fibers.

  7. Coating of carbon fibers -- The strength of the fibers

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, T. [Alusingen GmbH, Singen (Germany); Peterlik, H.; Kromp, K. [Univ. Wien, Vienna (Austria). Inst. fuer Festkoerperphysik

    1995-01-01

    The 6k carbon fiber Torayca T800H was coated with pyrolytic carbon by a CVD process. Fiber bundles were tested and evaluated. By this procedure, the whole distribution of the failure probability with respect to the fiber strength is obtained in a single experiment. The 50% strength of the fiber bundle, i.e., the strength at which 50% of the fibers in the bundle are broken, is inversely proportional to the square root of the thickness of the coating. By relating the strength to the defect size according to linear-elastic fracture mechanics (LEFM), the probability density function of the defects was derived. It is Weibull-shaped for the uncoated fiber and shows an increasing bimodal shape for the increasing coating thicknesses.

  8. Piezoelectric ceramic fibers for active fiber composites: a comparative study

    Science.gov (United States)

    Kornmann, Xavier; Huber, Christian; Elsener, Hans-Rudolf

    2003-08-01

    The morphology and the free strain performances of three different piezoelectric ceramic fibers used for the manufacture of active fiber composites (AFCs) have been investigated. The morphology of the fibers has a direct influence on the manufacture of the AFCs. Fibers with non-uniform diameters are more difficult to contact with the interdigitated electrodes and can be the cause of irreparable damages in AFCs. An indirect method requiring the use of a simple analytical model is proposed to evaluate the free strain of active fiber composites. This indirect method presents a relatively good agreement with direct free strain measurements performed with strain gages glued on both sides of an AFC. The results show a systematic difference of ca. 20 % between the indirect and the direct methods. However, the indirect method did not permit to see differences of piezoelectric performance between the types of fibers.

  9. Cardiovascular benefits of dietary fiber.

    Science.gov (United States)

    Satija, Ambika; Hu, Frank B

    2012-12-01

    The relationship between dietary fiber and risk of cardiovascular disease (CVD) has been extensively studied. There is considerable epidemiological evidence indicating an inverse association between dietary fiber intake and CVD risk. The association has been found to be stronger for cereal fiber than for fruit or vegetable fiber, and several studies have also found increased whole grain consumption to be associated with CVD risk reduction. In light of this evidence, recent US dietary guidelines have endorsed increased consumption of fiber rich whole grains. Regular consumption of dietary fiber, particularly fiber from cereal sources, may improve CVD health through multiple mechanisms including lipid reduction, body weight regulation, improved glucose metabolism, blood pressure control, and reduction of chronic inflammation. Future research should focus on various food sources of fiber, including different types of whole grains, legumes, fruits, vegetables, and nuts, as well as resistant starch in relation to CVD risk and weight control; explore the biological mechanisms underlying the cardioprotective effect of fiber-rich diets; and study different ethnic groups and populations with varying sources of dietary fiber.

  10. External reinforcing of fiber concrete constructions by carbon fiber tapes

    OpenAIRE

    S.V. Klyuyev; Yu.V. Guryanov

    2013-01-01

    Strengthening the concrete and reinforced concrete structures with carbon fiber tapes is very actively applied in Europe nowadays. In Russia composites based on carbon fiber have also widely spread recently. The main advantages of these materials for strengthening structures are its high specific strength (strength-weight ratio) and strength-to-density ratio.Experimental studies on strengthening and restoration of the constructions were held. Flexible fiber concrete constructions based on man...

  11. A Large Area Fiber Optic Gyroscope on multiplexed fiber network

    CERN Document Server

    Clivati, Cecilia; Costanzo, Giovanni A; Mura, Alberto; Pizzocaro, Marco; Levi, Filippo

    2012-01-01

    We describe a fiber optical gyroscope based on the Sagnac effect realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km^2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about 1e-8 (rad/s)/sqrt(Hz), thus approaching ring laser gyroscopes without using narrow-linewidth laser nor sophisticated optics. The proposed gyroscope is sensitive enough for seismic applications, opening new possibilities for this kind of optical fiber sensors

  12. Optical studies of directly synthesized trans-polyacetylene films

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, T. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan); Suruga, K. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan); Natsume, N. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan); Ishikawa, K. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan); Takezoe, H. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan); Fukuda, A. [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152 (Japan)

    1995-03-01

    We studied optical spectra of directly synthesized trans-polyacetylene films. Reflection and resonance Raman spectra show that effective conjugation length distribution has longer average length and narrower width than that of ordinary thermoisomerized films. Moreover, ESR spectra show that directly synthesized films have fewer defects than ordinary thermoisomerized films. (orig.)

  13. Syntheses of (±-Romucosine and (±-Cathafiline

    Directory of Open Access Journals (Sweden)

    Surachai Nimgirawath

    2006-11-01

    Full Text Available The structures previously assigned to (--romucosine and (+-cathafiline, N-(methoxycarbonyl aporphine alkaloids from Rollina mucosa (Annonaceae and Cassytha filiformis (Lauraceae respectively, have been confirmed by total syntheses of the racemic substances. The key step of the syntheses involved formation of ring C of the aporphines by a radical-initiated cyclisation.

  14. FIBER ORIENTATION IN INJECTION MOLDED LONG CARBON FIBER THERMOPLASTIC COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin; Nguyen, Ba Nghiep; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Costa, Franco; Jin, Xiaoshi; Tucker III, Charles L.; Fifield, Leonard S.

    2015-03-23

    A set of edge-gated and center-gated plaques were injection molded with long carbon fiber-reinforced thermoplastic composites, and the fiber orientation was measured at different locations of the plaques. Autodesk Simulation Moldflow Insight (ASMI) software was used to simulate the injection molding of these plaques and to predict the fiber orientation, using the anisotropic rotary diffusion and the reduced strain closure models. The phenomenological parameters of the orientation models were carefully identified by fitting to the measured orientation data. The fiber orientation predictions show very good agreement with the experimental data.

  15. Homogenization of long fiber reinforced composites including fiber bending effects

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Niordson, Christian Frithiof

    2016-01-01

    This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows...... of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization...

  16. Morphological control of porous SiC templated by As-synthesized form of mesoporous silica.

    Science.gov (United States)

    Selvan, Sakthivel Tamil; Aldeyab, Salem S; Zaidi, S M Javaid; Arivuoli, Dakshinamoorthy; Ariga, Katsuhiko; Mori, Toshiyuki; Vinu, Ajayan

    2011-08-01

    Porous silicon carbide with fiber like morphology was successfully prepared via a hard templating approach using as-synthesized form of mesoporous silica SBA-15 as template and sucrose as carbon precursor. The obtained materials have been characterized by various sophisticated techniques such as XRD, nitrogen adsorption, HRTEM, HRSEM, FT-IR and TGA. The XRD and the nitrogen adsorption results revealed that the materials are highly crystalline and exhibit porous structure with excellent textural characteristics. It has been demonstrated that the morphology of the materials can be finely controlled from rod shaped morphology to fiber like nanostructures by the simple adjustment of the reaction time from 5 to 12 h at the reaction temperature of 1300 degrees C. The reaction time of 12 h at 1300 degrees C was found to be the best condition to obtain highly crystalline nanofiber like morphology. The obtained materials display beautiful nanofiber morphology which has the diameter of 20 to 60 nm and a length of 7 to 10 microm which is much longer than the previously reported SiC nanofibers.

  17. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    Directory of Open Access Journals (Sweden)

    Anand Kumar Veeramachineni

    2016-06-01

    Full Text Available Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA, Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC and Field Emission Scanning Electronic Microscopy (FESEM. The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient.

  18. Gold island fiber optic sensor

    Science.gov (United States)

    Meriaudeau, Fabrice; Wig, A. G.; Passian, A.; Downey, Todd R.; Buncick, Milan; Ferrell, Trinidad L.

    1999-12-01

    A fiber optic chemical sensor based on gold-island surface plasmon excitation is presented. The sensing part of the fiber is the end of the fiber onto which a thin layer of gold has been deposited to form a particulate surface. Annealing the gold reshapes the particles and produces an optical absorbance near 535 nm with the fiber in air. The optical absorption resonance of the gold particles is shifted if the fiber is immersed in a medium other than air. These resonance shifts are examined by transmission spectroscopy through the fiber. Experimental results for the sensitivity and dynamic range in the measurement of liquid solutions are in agreement with a basic theoretical model which characterizes the surface plasmon using nonretarded electrodynamics.

  19. Fiber laser development for LISA

    Energy Technology Data Exchange (ETDEWEB)

    Numata, Kenji [Department of Astronomy, University of Maryland, College Park, Maryland, 20742 (United States); Chen, Jeffrey R [NASA Goddard Space Flight Center, Laser and electro-optics branch, Code 554, Greenbelt, Maryland, 20771 (United States); Camp, Jordan, E-mail: kenji.numata@nasa.go [NASA Goddard Space Flight Center, Gravitational astrophysics branch, Code 663, Greenbelt, Maryland, 20771 (United States)

    2010-05-01

    We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064 nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100 kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

  20. Fiber laser development for LISA

    CERN Document Server

    Numata, Kenji; Camp, Jordan

    2010-01-01

    We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

  1. Fiber Laser Development for LISA

    Science.gov (United States)

    Numata, Kenji; Chen, Jeffrey R.

    2009-01-01

    We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

  2. Impact resistance of fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1982-01-01

    Stress-strain curves are obtained for a variety of glass fiber and carbon fiber reinforced plastics in dynamic tension, over the stress-strain range of 0.00087-2070/sec. The test method is of the one-bar block-to-bar type, using a rotating disk or a pendulum as the loading apparatus and yielding accurate stress-strain curves up to the breaking strain. In the case of glass fiber reinforced plastic, the tensile strength, strain to peak impact stress, total strain and total absorbed energy all increase significantly as the strain rate increases. By contrast, carbon fiber reinforced plastics show lower rates of increase with strain rate. It is recommended that hybrid composites incorporating the high strength and rigidity of carbon fiber reinforced plastic with the high impact absorption of glass fiber reinforced plastics be developed for use in structures subjected to impact loading.

  3. Dietary fiber and retrograde starch.

    Science.gov (United States)

    Zivković, R

    1998-01-01

    The history of the recognition of the importance of dietary fiber, their current classification into water-soluble and water-insoluble fiber, and lignin, a single non-carbohydrate fiber, and the physiologic role of dietary fiber, with particular reference to retrograde starch resistance to small intestine digestion, are briefly presented. Dietary fiber are highly hygroscopic, thus they greatly contribute to stool voluminosity by binding water, decrease the glycemic index, and exert a protective action, via an as yet unknown mechanism, against the occurrence of colon cancer. It should be added that some dietary fiber decrease the concentration of cholesterol in the blood, i.e. in the human body. The importance of the methodology used for NSP determination is underlined, since some methods determine only some of the polysaccharides, other also measure some other substances, whereas Englyst's method determines NSP only.

  4. Performance of the Bean-protein Fiber

    Institute of Scientific and Technical Information of China (English)

    韩光亭; 杜宁; 孙亚宁

    2003-01-01

    The methods in testing the bean-protein fiber and the standards used were simply introduced. The fiber's mechanical and chemical performances were further analyzed. And the correlative performance of the bean-protein fibers and other natural fibers have been compared, then full knowledge of the fiber's performance was concluded.

  5. Fiber optic sensor and method for making

    Science.gov (United States)

    Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

    2010-05-18

    A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

  6. Fiber-reinforced cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Mindess, S. (Univ. of British Columbia, Vancouver, British Columbia (CA)); Skalny, J. (W.R. Grace and Co., Columbia, MD (US))

    1991-01-01

    There were five main themes: toughening mechanisms; synthetic and glass fibers; cracking under static and impact loading; new fibers and processing techniques; and applications. The lively exchange of ideas that occurred during the discussions made it clear that the development of high-performance, durable fiber cements and concretes is well advanced. Most of the papers presented at the symposium are included in this volume.

  7. Dyeing Properties of Basofil Fiber

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong; DAI Jin-jin

    2002-01-01

    The structures and properties of Basofil fiber were studied using X- rays small angle diffraction analysis,differential- scanuing calorimeter and scanning electron microscopy. Disperse dyes, acid dyes and reactive dyes had been tried for dyeing Basefil fiber. It was shown disperse dyes were superior to other ones. The two series of high temperature dyes and low temperature dyes were compared for their suitability for Basofil fiber, and their dyeing behaviors were determined.

  8. Optical coatings for fiber lasers

    Institute of Scientific and Technical Information of China (English)

    HONG Dong-mei; ZHU Zhen; YUE Wei

    2005-01-01

    Fiber laser is the future development direction for the high energy lasers. This paper describs two kinds of optical coatings for fiber laser, including long and short wave pass filters. The one characteristic of fiber laser coatings lies in that coatings should separate two closely wavelength light including laser pump wavelength (980 nm) and laser irradiation wavelength(1 050~1 100 nm). At the same time, the coatings should have high laser damage threshold.

  9. STUDY OF A NEW POROUS PLASTIC OPTICAL FIBER PROBE BASED ON MOLECULAR LUMINESCENCE%基于分子发光的新型多孔塑料光纤传感探头的研究

    Institute of Scientific and Technical Information of China (English)

    谢增鸿; 郭良洽; 林旭聪; 陈国南

    2003-01-01

    A new porous plastic optical fiber probe was synthesized and proposed for preparation of optical chemical sensor. The basic principle,fabrication and characteristics of the porous plastic optical fiber probe are described in detail. The polymer fiber was made from the stock mixture of functional monomer,cross-linking reagent,pore-forming reagent and indicator. And it behaves great advantages as an optical fiber probe. This new porous plastic optical fiber probe has been used for preparing some optical chemical sensors, and these probes have been used for determination of halides, mercury, ammonia, oxygen and pH.

  10. Fiber-Optic Sensor Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Constructs and evaluates fiber-optic sensors for a variety of measurands. These measurands include acoustic, pressure, magnetic, and electric field as well...

  11. Capillary stretching of elastic fibers

    Science.gov (United States)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  12. In-fiber integrated accelerometer.

    Science.gov (United States)

    Peng, Feng; Yang, Jun; Li, Xingliang; Yuan, Yonggui; Wu, Bing; Zhou, Ai; Yuan, Libo

    2011-06-01

    A compact in-fiber integrated fiber-optic Michelson interferometer based accelerometer is proposed and investigated. In the system, the sensing element consists of a twin-core fiber acting as a bending simple supported beam. By demodulating the optical phase shift, we obtain that the acceleration is proportional to the force applied on the central position of the twin-core fiber. A simple model has been established to calculate the sensitivity and resonant frequency. The experimental results show that such an accelerometer has a sensitivity of 0.09 rad/g at the resonant frequency of 680 Hz.

  13. Photonic crystal fibers in biophotonics

    Science.gov (United States)

    Tuchin, Valery V.; Skibina, Julia S.; Malinin, Anton V.

    2011-12-01

    We observed recent experimental results in area of photonic crystal fibers appliance. Possibility of creation of fiberbased broadband light sources for high resolution optical coherence tomography is discussed. Using of femtosecond pulse laser allows for generation of optical radiation with large spectral width in highly nonlinear solid core photonic crystal fibers. Concept of exploitation of hollow core photonic crystal fibers in optical sensing is demonstrated. The use of photonic crystal fibers as "smart cuvette" gives rise to efficiency of modern optical biomedical analysis methods.

  14. Health benefits of prebiotic fibers.

    Science.gov (United States)

    Meyer, Diederick

    2015-01-01

    This chapter describes the various compounds that can act as prebiotic fibers: their structure, occurrence, production, and physiological effects (health effects) will be presented. The basis for the description is the latest definitions for dietary fibers and for prebiotics. Using as much as possible data from human studies, both the fiber and the prebiotic properties will be described of a variety of compounds. Based on the presented data the latest developments in the area of prebiotics, fibers and gut and immune health will be discussed in more detail as they show best what the potential impact of prebiotics on health of the human host might be.

  15. Fibers and Conductive Films Using Silver Nanoparticles and Nanowires by Near-Field Electrospinning Process

    Directory of Open Access Journals (Sweden)

    Cheng-Tang Pan

    2015-01-01

    Full Text Available The silver nanowires (AgNWs and silver nanoparticles (AgNPs were synthesized. With near-field electrospinning (NFES process, fibers and thin films with AgNPs and AgNWs were fabricated. In the NFES process, 10 k voltage was applied and the AgNPs and AgNWs fibers can be directly orderly collected without breaking and bending. Then, the characteristics of the fibers were analyzed by four-point probe and EDS. The conductive film was analyzed. When the thickness of films with AgNWs and AgNPs was 1.6 µm, the sheet resistance of films was 0.032 Ω/sq which was superior to that of the commercial ITO. The transmissivity of films was analyzed. The transmissivity was inversely proportional to sheet resistance of the films. In the future, the fibers and films can be used as transparent conductive electrodes.

  16. Preparation of ferromagnetic binary alloy fine fibers byorganic gel-thermal reduction process

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiang-qian; CAO Kai; ZHOU Jian-xin

    2006-01-01

    Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel, iron-cobalt and cobalt-nickel were prepared by the organic gel-thermal reduction process from the raw materials of critic acid and metal salts. These alloy fibers synthesized were featured with a diameter of about 1 μm and a length as long as 1 m. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of the gel precursors were characterized by FTIR, XRD, TG/DSC and SEM. The gel spinnability largely depends on the molecular structure of metal- carboxylates formed during the gel formation. The gel consisting of linear-type structural molecules shows good spinnability.

  17. Photocatalytic self-cleaning properties of cellulosic fibers modified by nano-sized zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Moafi, Hadi Fallah; Shojaie, Abdollah Fallah, E-mail: a.f.shojaie@guilan.ac.ir; Zanjanchi, Mohammad Ali

    2011-03-31

    Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis irradiation. The photocatalytic activity of the treated fabrics was fully maintained performing several cycles of photodegradation.

  18. Fabrication of solid-cladding photonic band gap fiber with air core

    Science.gov (United States)

    Kujawa, I.; Pysz, D.; Buczyński, R.; Filipkowski, A.; Nowosielski, J.; Stępień, R.

    2008-06-01

    In this paper we report on fabrication of all-Solid photonic Cladding and Air Core fiber (SCAC fiber). As far as we know it is a first reported fabrication of such PCF. Microrods are made of commercially available lead-oxide F2 glass (SCHOTT Inc.) with a refractive index nD=1.619, while as background we use a borosilicate NC21 glass synthesized in-house at ITME with a refractive index nD=1.533. A fabricated fiber has a lattice constant of Λ~7.49μm and microrods diameter of d~4.0μm. Air core has a diameter of DR=3.67μm and total fiber diameter is Dfiber=123.80μm.

  19. Synthesis and Preparation of Polysulfone Hollow Fiber Chelating Membrane Modified with Thiourea

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; HUANG Lei; XIAO Feng

    2006-01-01

    Several kinds of chloromethyl polysulfones (CMPF) with different chlorinity and reactive groups were synthesized by Friedel-crafts reaction, which could be utilized as reactively matrix membrane materials. The CMPF hollow matrix membranes were prepared with phase inversion by utilization of CMPF/additive/DMAC casting solution and CMPF as membrane materials. It was found that the effects of additive content, bore liquid and dry spinning distance on the structure of CMPF hollow fiber matrix membrane were different. A high qualified polysulfone hollow fiber chelating membrane modified with thiourea as chelating groups was prepared using CMPF as membrane matrix materials,through the reaction between thiourea and CMPF hollow fiber matrix membrane to afford the methyl iso-thiourium polysulfone. The experimental results showed that thermal drawing could increase the mechanical properties of matrix membrane, and the thermal treatment could increase the homogeneity and stability of the structure of polysulfone hollow fiber chelating membrane modified with thiourea.

  20. Ceramic fibers for matrix composites in high-temperature engine applications

    Science.gov (United States)

    Baldus; Jansen; Sporn

    1999-07-30

    High-temperature engine applications have been limited by the performance of metal alloys and carbide fiber composites at elevated temperatures. Random inorganic networks composed of silicon, boron, nitrogen, and carbon represent a novel class of ceramics with outstanding durability at elevated temperatures. SiBN(3)C was synthesized by pyrolysis of a preceramic N-methylpolyborosilazane made from the single-source precursor Cl(3)Si-NH-BCl(2). The polymer can be processed to a green fiber by melt-spinning, which then undergoes an intermediate curing step and successive pyrolysis. The ceramic fibers, which are presently produced on a semitechnical scale, combine several desired properties relevant for an application in fiber-reinforced ceramic composites: thermal stability, mechanical strength, high-temperature creep resistivity, low density, and stability against oxidation or molten silicon.

  1. Ytterbium-Phosphate Glass for Microstructured Fiber Laser

    Directory of Open Access Journals (Sweden)

    Ryszard Stępień

    2014-06-01

    Full Text Available In the paper, we report on the development of a synthesis and melting method of phosphate glasses designed for active microstructured fiber manufacturing. Non-doped glass synthesized in a P2O5-Al2O3-BaO-ZnO-MgO-Na2O oxide system served as the matrix material; meanwhile, the glass was doped with 6 mol% (18 wt% of Yb2O3, as fiber core. The glasses were well-fitted in relation to optical (refractive index and thermal proprieties (thermal expansion coefficient, rheology. The fiber with the Yb3+-doped core, with a wide internal photonic microstructure for a laser pump, as well as with a high relative hole size in the photonic outer air-cladding, was produced. The laser built on the basis of this fiber enabled achieving 8.07 W of output power with 20.5% slope efficiency against the launched pump power, in single-mode operation M2 = 1.59, from a 53 cm-long cavity.

  2. Apatite bone cement reinforced with calcium silicate fibers.

    Science.gov (United States)

    Motisuke, Mariana; Santos, Verônica R; Bazanini, Naiana C; Bertran, Celso A

    2014-10-01

    Several research efforts have been made in the attempt to reinforce calcium phosphate cements (CPCs) with polymeric and carbon fibers. Due to their low compatibility with the cement matrix, results were not satisfactory. In this context, calcium silicate fibers (CaSiO3) may be an alternative material to overcome the main drawback of reinforced CPCs since, despite of their good mechanical properties, they may interact chemically with the CPC matrix. In this work CaSiO3 fibers, with aspect ratio of 9.6, were synthesized by a reactive molten salt synthesis and used as reinforcement in apatite cement. 5 wt.% of reinforcement addition has increased the compressive strength of the CPC by 250% (from 14.5 to 50.4 MPa) without preventing the cement to set. Ca and Si release in samples containing fibers could be explained by CaSiO3 partial hydrolysis which leads to a quick increase in Ca concentration and in silica gel precipitation. The latter may be responsible for apatite precipitation in needle like form during cement setting reaction. The material developed presents potential properties to be employed in bone repair treatment.

  3. Assessment voice synthesizers for reading in digital books

    Directory of Open Access Journals (Sweden)

    Sérvulo Fernandes da Silva Neto

    2013-07-01

    Full Text Available The digital accessibility shows ways to information access in digital media that assist people with different types of disabilities to a better interaction with the computer independent of its limitations. Of these tools are composed by voice synthesizers, that supposedly simplifying their access to any recorded knowledge through digital technologies. However such tools have emerged originally in countries foreign language. Which brings us to the following research problem: the voice synthesizers are appropriate for reading digital books in the Portuguese language? The objective of this study was to analyze and classify different software tools voice synthesizers in combination with software digital book readers to support accessibility to e-books in Portuguese. Through literature review were identified applications software voice synthesizers, composing the sample analyzed in this work. We used a simplified version of the method of Multiple Criteria Decision Support - MMDA, to assess these. In the research 12 were considered readers of e-books and 11 software voice synthesizer, tested with six formats of e-books (E-pub, PDF, HTML, DOC, TXT, and Mobi. In accordance with the results, the software Virtual Vision achieved the highest score. Relative to formats, it was found that the PDF has measured a better score when summed the results of the three synthesizers. In the studied universe contacted that many synthesizers simply cannot be used because they did not support the Portuguese language.

  4. Tungsten diselenide Q-switched erbium-doped fiber laser

    Science.gov (United States)

    Chen, Bohua; Zhang, Xiaoyan; Guo, Chaoshi; Wu, Kan; Chen, Jianping; Wang, Jun

    2016-08-01

    We report a tungsten diselenide (WSe2) polyvinyl alcohol (PVA)-based, saturable absorber and related experiment results of a Q-switched fiber laser. WSe2-PVA film is synthesized by liquid phase exfoliation method, and its saturable absorption is measured via a nonlinear transmission experiment. The result shows that WSe2-PVA saturable absorber has a modulation depth of 3.5%, which means it has potential for generating an ultrafast pulse laser. We apply this absorber into a ring-cavity erbium-doped fiber laser and obtain Q-switched pulses under appropriate pump power. Our work demonstrates the reliable nonlinear optical characteristics of WSe2 and the feasibility for this two-dimensional material to be applied in the field of nonlinear optics.

  5. Experiments on room temperature optical fiber-fiber direct bonding

    Science.gov (United States)

    Hao, Jinping; Yan, Ping; Xiao, Qirong; Wang, Yaping; Gong, Mali

    2012-08-01

    High quality permanent connection between optical fibers is a significant issue in optics and communication. Studies on room temperature optical large diameter fiber-fiber direct bonding, which is essentially surface interactions of glass material, are presented here. Bonded fiber pairs are obtained for the first time through the bonding technics illustrated here. Two different kinds of bonding technics are provided-fresh surface (freshly grinded and polished) bonding and hydrophobic surface (activated by H2SO4 and HF) bonding. By means of fresh surface bonding, a bonded fiber pair with light transmitting efficiency of 98.1% and bond strength of 21.2 N is obtained. Besides, in the bonding process, chemical surface treatment of fibers' end surfaces is an important step. Therefore, various ways of surface treatment are analyzed and compared, based on atomic force microscopy force curves of differently disposed surfaces. According to the comparison, fresh surfaces are suggested as the prior choice in room temperature optical fiber-fiber bonding, owing to their larger adhesive force, attractive force, attractive distance, and adhesive range.

  6. Scintillating fiber detector

    CERN Document Server

    Vozak, Matous

    2016-01-01

    NA61 is one of the physics experiments at CERN dedicated to study hadron states coming from interactions of SPS beams with various targets. To determine the position of a secondary beam, three proportional chambers are placed along the beamline. However, these chambers tend to have slow response. In order to obtain more precise time information, use of another detector is being considered. Fast response and compact size is making scintillation fiber (SciFi) with silicon photomultiplier (Si-PM) read out a good candidate. This report is focused on analysing data from SciFi collected in a test beam at the beginning of July 2016.

  7. Higher Order Mode Fibers

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller

    . The research presented in this thesis falls in three parts. In the first part, a first time demonstration of the break of the azimuthal symmetry of the Bessel-like LP0X modes is presented. This effect, known as the bowtie effect, causes the mode to have an azimuthal dependence as well as a quasi...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

  8. Actively doped solid core Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Broeng, Jes; Olausson, Christina Bjarnal Thulin; Lyngsøe, Jens Kristian;

    2010-01-01

    Solid photonic bandgap fibers offer distributed spectral filtering with extraordinary high suppression. This opens new possibilities of artificially tailoring the gain spectrum of fibers. We present record-performance of such fibers and outline their future applications....

  9. Polymer optical fiber bragg grating sensors

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu; Andresen, Søren

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings are reported. We have written fiber Bragg gratings for 1550 nm and 850 nm operations, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  10. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  11. Carbon Fiber Biocompatibility for Implants

    Directory of Open Access Journals (Sweden)

    Richard Petersen

    2016-01-01

    Full Text Available Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8 and 0.8 mm at 41.6% vs. 19.5% (p < 10−4, respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

  12. Preparation of Hydroxyapatite Fibers by the Homogeneous Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper discussed the preparing process of hydroxyapatite fibers which were widely used as reinforcement for biomedical materials by homogeneous precipitation method.The needle-like hydroxyapatite crystals were synthesized in an aqueous system.They were transferred from precursors-dicalcium phosphate anhydrate and octacalcium phosphate crystals.The reaction conditions were well controlled in order to obtain crystals in given morphology.The products were characterized by X-ray powder diffractometry(XRD),scanning electron microscopy (SEM) and infrared spectroscopy(IR).They were verified to be hydroxyapatite crystals with needle-like in shape.

  13. Infrared fiber coupled acousto-optic tunable filter spectrometer

    Science.gov (United States)

    Levin, K. H.; Kindler, E.; Ko, T.; Lee, F.; Tran, D. C.; Tapphorn, R. M.

    A spectrometer design is introduced which combines an acoustooptic tunable filter (AOTF) and IR-transmitting flouride-glass fibers. The AOTF crystal is fabricated from TeO2 and permits random access to any wavelength in less than 50 microseconds, and the resulting spectrometer is tested for the remote analysis of gases and hydrocarbons. The AOTF spectrometer, when operated with a high-speed frequency synthesizer and optimized algorithms, permits accurate high-speed spectroscopy in the mid-IR spectral region.

  14. Preparation of Amino-Modified PAN Fibers with Triethylenetetramine as Aminating Reagents and Their Application in CO2 Adsorption

    Directory of Open Access Journals (Sweden)

    Wenbo Zhao

    2014-01-01

    Full Text Available Amino-modified polyacrylonitrile (AMPAN fiber was synthesized by the reaction of polyacrylonitrile (PAN fiber and triethylenetetramine (TETA in the presence of water. The effect of water amount, reaction temperature, and time on the weight increase degree and alkali content of the AMPAN fiber was investigated in detail. The characterization results indicated that TETA could be grafted onto the surface of PAN fiber by this method. However, the highest adsorption capacity of the AMPAN fibers was only 0.09 g/g even at 15 bar and 50°C, which was much lower than the porous materials. The reason for this result may be related to its low surface area.

  15. Single-branch Er:fiber frequency comb for optical synthesis at the $10^{-18}$ level

    CERN Document Server

    Leopardi, Holly; Quinlan, Franklyn; Olson, Judith; Diddams, Scott; Fortier, Tara

    2016-01-01

    Laser frequency combs based on erbium-doped fiber mode-locked lasers have shown great potential for compact, robust and efficient optical clock comparisons. However, to simultaneously compare multiple optical clock species, fiber laser frequency combs typically require multiple amplifiers and fiber optic paths that reduce the achievable frequency stability near 1 part in $10^{16}$ at 1s. In this paper we describe an erbium-fiber laser frequency comb that overcomes these conventional challenges and supports optical frequency synthesis at the millihertz level, or fractionally $3 x 10^{-18}$ $tau^{-1/2}$ by ensuring that all critical fiber paths are within the servo-controlled feedback loop. We demonstrate the application of this frequency comb as a synthesizer for optical clocks operating across a wavelength range from 650 nm to 2100 nm.

  16. Photonic crystal fiber modelling and applications

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Libori, Stig E. Barkou

    2001-01-01

    Photonic crystal fibers having a microstructured air-silica cross section offer new optical properties compared to conventional fibers for telecommunication, sensor, and other applications. Recent advances within research and development of these fibers are presented.......Photonic crystal fibers having a microstructured air-silica cross section offer new optical properties compared to conventional fibers for telecommunication, sensor, and other applications. Recent advances within research and development of these fibers are presented....

  17. Photonic crystal fibers: fundamentals to emerging applications

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard

    2005-01-01

    A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers.......A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers....

  18. High-birefringent photonic crystal fiber

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou; Broeng, Jes; Knudsen, Erik

    2001-01-01

    A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber.......A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber....

  19. Quantitive DNA Fiber Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chun-Mei; Wang, Mei; Greulich-Bode, Karin M.; Weier, Jingly F.; Weier, Heinz-Ulli G.

    2008-01-28

    Several hybridization-based methods used to delineate single copy or repeated DNA sequences in larger genomic intervals take advantage of the increased resolution and sensitivity of free chromatin, i.e., chromatin released from interphase cell nuclei. Quantitative DNA fiber mapping (QDFM) differs from the majority of these methods in that it applies FISH to purified, clonal DNA molecules which have been bound with at least one end to a solid substrate. The DNA molecules are then stretched by the action of a receding meniscus at the water-air interface resulting in DNA molecules stretched homogeneously to about 2.3 kb/{micro}m. When non-isotopically, multicolor-labeled probes are hybridized to these stretched DNA fibers, their respective binding sites are visualized in the fluorescence microscope, their relative distance can be measured and converted into kilobase pairs (kb). The QDFM technique has found useful applications ranging from the detection and delineation of deletions or overlap between linked clones to the construction of high-resolution physical maps to studies of stalled DNA replication and transcription.

  20. Two Octaves Supercontinuum Generation in Lead-Bismuth Glass Based Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Ryszard Buczynski

    2014-06-01

    Full Text Available In this paper we report a two octave spanning supercontinuum generation in a bandwidth of 700–3000 nm in a single-mode photonic crystal fiber made of lead-bismuth-gallate glass. To our knowledge this is the broadest supercontinuum reported in heavy metal oxide glass based fibers. The fiber was fabricated using an in-house synthesized glass with optimized nonlinear, rheological and transmission properties in the range of 500–4800 nm. The photonic cladding consists of 8 rings of air holes. The fiber has a zero dispersion wavelength (ZDW at 1460 nm. Its dispersion is determined mainly by the first ring of holes in the cladding with a relative hole size of 0.73. Relative hole size of the remaining seven rings is 0.54, which allows single mode performance of the fiber in the infrared range and reduces attenuation of the fundamental mode. The fiber is pumped into anomalous dispersion with 150 fs pulses at 1540 nm. Observed spectrum of 700–3000 nm was generated in 2 cm of fiber with pulse energy below 4 nJ. A flatness of 5 dB was observed in 950–2500 nm range.

  1. Synthesis of high performance ceramic fibers by chemical vapor deposition for advanced metallics reinforcing

    Science.gov (United States)

    Revankar, Vithal; Hlavacek, Vladimir

    1991-01-01

    The chemical vapor deposition (CVD) synthesis of fibers capable of effectively reinforcing intermetallic matrices at elevated temperatures which can be used for potential applications in high temperature composite materials is described. This process was used due to its advantage over other fiber synthesis processes. It is extremely important to produce these fibers with good reproducible and controlled growth rates. However, the complex interplay of mass and energy transfer, blended with the fluid dynamics makes this a formidable task. The design and development of CVD reactor assembly and system to synthesize TiB2, CrB, B4C, and TiC fibers was performed. Residual thermal analysis for estimating stresses arising form thermal expansion mismatch were determined. Various techniques to improve the mechanical properties were also performed. Various techniques for improving the fiber properties were elaborated. The crystal structure and its orientation for TiB2 fiber is discussed. An overall view of the CVD process to develop CrB2, TiB2, and other high performance ceramic fibers is presented.

  2. Effect of steaming on shape memory polyurethane fibers with various hard segment contents

    Science.gov (United States)

    Zhu, Yong; Hu, Jinlian; Yeung, Lap-Yan; Lu, Jing; Meng, Qinghao; Chen, Shaojun; Yeung, Kwok-wing

    2007-08-01

    To illustrate the effect of post-treatment high-pressure steaming and hard segment content on shape memory polyurethane (SMPU) fiber, a series of shape memory polyurethane having various hard segment contents was synthesized with the pre-polymerization method, spun with a wet spinning process and treated with high pressure saturated water vapor. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), wide angle x-ray diffraction (WAXD), mechanical testing and cyclic tensile testing were conducted to investigate the particular thermal/mechanical properties, crystallization of hard segments and shape memory properties of SMPU fibers. In addition, in the light of a comparison between the original and the treated SMPU fiber, the effect of steaming post-treatment in SMPU fibers with various hard segment contents was illustrated. The steaming treatment gives rise to a higher elongation ratio at break, lower tenacity and initial modulus. Hard segment crystallization can be induced, especially in fiber with higher hard segment content after treatment. The glass transition temperature of the soft segment of SMPU fibers was decreased after steaming and the trends are most likely significant in high hard segment content specimens. Steaming with high pressure saturated water vapor can eliminate the thermal shrinkage and provide dimensional stability to the original SMPU fibers. The recoverability remains well in all treated specimens, but the fixity ability decreases with the decrease of hard segment content.

  3. Broadband terahertz fiber directional coupler

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd

    2010-01-01

    We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber...

  4. Fiber optic-based biosensor

    Science.gov (United States)

    Ligler, Frances S.

    1991-01-01

    The NRL fiber optic biosensor is a device which measures the formation of a fluorescent complex at the surface of an optical fiber. Antibodies and DNA binding proteins provide the mechanism for recognizing an analyze and immobilizing a fluorescent complex on the fiber surface. The fiber optic biosensor is fast, sensitive, and permits analysis of hazardous materials remote from the instrumentation. The fiber optic biosensor is described in terms of the device configuration, chemistry for protein immobilization, and assay development. A lab version is being used for assay development and performance characterization while a portable device is under development. Antibodies coated on the fiber are stable for up to two years of storage prior to use. The fiber optic biosensor was used to measure concentration of toxins in the parts per billion (ng/ml) range in under a minute. Immunoassays for small molecules and whole bacteria are under development. Assays using DNA probes as the detection element can also be used with the fiber optic sensor, which is currently being developed to detect biological warfare agents, explosives, pathogens, and toxic materials which pollute the environment.

  5. Electrospun Fibers for Composites Applications

    Science.gov (United States)

    2014-02-01

    from Applied Poleramic, Inc.) for dynamic mechanical analysis (DMA) experiments, and vacuum-assisted transfer molding ( VARTM ) was evaluated. The flow...of resin in the VARTM process led to localized disruption of the fiber mats (e.g., bunching of fibers), reducing the yield of the final part. The

  6. Safety Precautions in Fiber Arts.

    Science.gov (United States)

    Hamilton, Marcia

    1979-01-01

    The author discusses the potential hazards of working with fibers, dyes, and wax in textile art projects: bacteria, dust, poisons, allergies, and fumes. Safety precautions for working with dyes are listed. This article is one of seven in this issue on fiber arts. (SJL)

  7. Nanomechanics of electrospun phospholipid fiber

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Nikogeorgos, Nikolaos; Lee, Seunghwan

    2015-01-01

    . At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip...

  8. Quantum cryptography using optical fibers.

    Science.gov (United States)

    Franson, J D; Lives, H

    1994-05-10

    Quantum cryptography permits the transmission of secret information whose security is guaranteed by the uncertainty principle. An experimental system for quantum crytography is implemented based on the linear polarization of single photons transmitted by an optical fiber. Polarization-preserving optical fiber and a feedback loop are employed to maintain the state of polarization. Error rates of less than 0.5% are obtained.

  9. Syntheses of (+)-cytisine, (-)-kuraramine, (-)-isokuraramine, and (-)-jussiaeiine A.

    Science.gov (United States)

    Honda, Toshio; Takahashi, Rie; Namiki, Hidenori

    2005-01-21

    Total syntheses of (+)-cytisine, (-)-kuraramine, (-)-isokuraramine, and (-)-jussiaeiine A were achieved via a samarium diiodide-promoted reductive deamination reaction, followed by simultaneous recyclization of a proline derivative to give the corresponding delta-lactam derivative, as a key step.

  10. GaN Nanowires Synthesized by Electroless Etching Method

    KAUST Repository

    Najar, Adel

    2012-01-01

    Ultra-long Gallium Nitride Nanowires is synthesized via metal-electroless etching method. The morphologies and optical properties of GaN NWs show a single crystal GaN with hexagonal Wurtzite structure and high luminescence properties.

  11. Synthesizing SoTL Institutional Initiatives toward National Impact

    Science.gov (United States)

    Simmons, Nicola

    2016-01-01

    This chapter draws on other authors' ideas in this issue, describing parallels and outlining distinctions toward a synthesized model for the development of SoTL initiatives at the institutional level and beyond.

  12. Handbook of fiber optics theory and applications

    CERN Document Server

    Yeh, Chai

    2013-01-01

    Dr. Yeh supplies a firm theoretical foundation in such topics as propagation of light through fibers, fiber fabrication, loss mechanisms, and dispersion properties. He then expands from this into such practical areas as fiber splicing, measuring loss in fibers, fiber-based communications networks, remote fiber sensors, and integrated optics. Whether involved in fiber optics research, design, or practical implementation of systems, this handbook will be extremely useful.Key Features* Here is a comprehensive, ""one-stop"" reference with state-of-the-art information on fiber optics Included is da

  13. Mayenite Synthesized Using the Citrate Sol-Gel Method

    Energy Technology Data Exchange (ETDEWEB)

    Ude, Sabina N [ORNL; Rawn, Claudia J [ORNL; Meisner, Roberta A [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Kirkham, Melanie J [ORNL; Jones, Gregory L. [University of Tennessee, Knoxville (UTK); Payzant, E Andrew [ORNL

    2014-01-01

    A citrate sol-gel method has been used to synthesize mayenite (Ca12Al14O33). X-ray powder diffraction data show that the samples synthesized using the citrate sol-gel method contained CaAl2O4 and CaCO3 along with mayenite when fired ex-situ in air at 800 C but were single phase when fired at 900 C and above. Using high temperature x-ray diffraction, data collected in-situ in air at temperatures of 600 C and below showed only amorphous content; however, data collected at higher temperatures indicated the first phase to crystallize is CaCO3. High temperature x-ray diffraction data collected in 4% H2/96% N2 does not show the presence of CaCO3, and Ca12Al14O33 starts to form around 850 C. In comparison, x-ray powder diffraction data collected ex-situ on samples synthesized using traditional solid-state synthesis shows that single phase was not reached until samples were fired at 1350 C. DTA/TGA data collected either in a nitrogen environment or air on samples synthesized using the citrate gel method suggest the complete decomposition of metastable phases and the formation of mayenite at 900 C, although the phase evolution is very different depending on the environment. Brunauer-Emmett-Teller (BET) measurements showed a slightly higher surface area of 7.4 0.1 m2/g in the citrate gel synthesized samples compared to solid-state synthesized sample with a surface area of 1.61 0.02 m2/g. SEM images show a larger particle size for samples synthesized using the solid-state method compared to those synthesized using the citrate gel method.

  14. Chemical Strategies for Template Syntheses of Composite Micro and Nanostructures.

    Science.gov (United States)

    2007-11-02

    syntheses can be accomplished within the pores of the alumina templates to make semiconductor tubules (27). Figure 5 shows that Ti02 tubules prepared...surface area forms have higher photo efficiencies (28). Ti02 /conductor nanocomposites may prove to be useful photocatalysts because the template...synthesized Ti02 nanostructures have very high surface areas (27). Furthermore, as discussed previously, each outer tubular Ti02 catalyst particle has

  15. Bacteriocins synthesized by Bacillus thuringiensis: generalities and potential applications

    OpenAIRE

    Salazar-Marroquín, Elma Laura; Galán-Wong, Luis J.; Moreno-Medina, Víctor Ricardo; Reyes-López, Miguel Ángel; Pereyra-Alférez, Benito

    2016-01-01

    The members of the Bacillus thuringiensis group, commonly known as Bt, produce a huge number of metabolites, which show biocidal and antagonistic activity. B. thuringiensis is widely known for synthesizing Cry, Vip and Cyt proteins, active against insects and other parasporins with biocidal activity against certain types of cancerous cells. Nevertheless, B. thuringiensis also synthesizes compounds with antimicrobial activity, especially bacteriocins. Some B. thuringiensis bacteriocins resembl...

  16. Coherent fiber supercontinuum for biophotonics.

    Science.gov (United States)

    Tu, Haohua; Boppart, Stephen A

    2013-09-01

    Biophotonics and nonlinear fiber optics have traditionally been two independent fields. Since the discovery of fiber-based supercontinuum generation in 1999, biophotonics applications employing incoherent light have experienced a large impact from nonlinear fiber optics, primarily because of the access to a wide range of wavelengths and a uniform spatial profile afforded by fiber supercontinuum. However, biophotonics applications employing coherent light have not benefited from the most well-known techniques of supercontinuum generation for reasons such as poor coherence (or high noise), insufficient controllability, and inadequate portability. Fortunately, a few key techniques involving nonlinear fiber optics and femtosecond laser development have emerged to overcome these critical limitations. Despite their relative independence, these techniques are the focus of this review, because they can be integrated into a low-cost portable biophotonics source platform. This platform can be shared across many different areas of research in biophotonics, enabling new applications such as point-of-care coherent optical biomedical imaging.

  17. Sensored fiber reinforced polymer grate

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Michael P.; Mack, Thomas Kimball

    2017-08-01

    Various technologies described herein pertain to a sensored grate that can be utilized for various security fencing applications. The sensored grate includes a grate framework and an embedded optical fiber. The grate framework is formed of a molded polymer such as, for instance, molded fiber reinforced polymer. Further, the grate framework includes a set of elongated elements, where the elongated elements are spaced to define apertures through the grate framework. The optical fiber is embedded in the elongated elements of the grate framework. Moreover, bending or breaking of one or more of the elongated elements can be detected based on a change in a characteristic of input light provided to the optical fiber compared to output light received from the optical fiber.

  18. Oxide Fiber Targets at ISOLDE

    CERN Document Server

    Köster, U; Carminati, D; Catherall, R; Cederkäll, J; Correia, J G; Crepieux, B; Dietrich, M; Elder, K; Fedosseev, V; Fraile-Prieto, L M; Franchoo, S; Fynbo, H O U; Georg, U; Giles, T; Joinet, A; Jonsson, O C; Kirchner, R; Lau, C; Lettry, Jacques; Maier, H J; Mishin, V I; Oinonen, M; Peräjärvi, K; Ravn, H L; Rinaldi, T; Santana-Leitner, M; Wahl, U; Weissman, L

    2003-01-01

    Many elements are rapidly released from oxide matrices. Some oxide powder targets show a fast sintering, thus losing their favorable release characteristics. Loosely packed oxyde fiber targets are less critical since they may maintain their open structure even when starting to fuse together at some contact points. The experience with various oxyde fiber targets (titania, zirconia, ceria and thoria) used in the last years at ISOLDE is reviewed. For short-lived isotopes of Cu, Ga and Xe the zirconia and ceria targets respectively provided significantly higher yields than any other target (metal foils, oxide powders, etc.) tested before. Titania fibers, which were not commercially available, were produced in a relic process by impregnation of a rayon felt in a titanium chloride solution and subsequent calcination by heating the dried felt in air. Thoria fibers were obtained either by the same process or by burning commercial gas lantern mantle cloth. In the future a beryllia fiber target could be used to produce...

  19. Degradation of methylene blue using biologically synthesized silver nanoparticles.

    Science.gov (United States)

    Vanaja, M; Paulkumar, K; Baburaja, M; Rajeshkumar, S; Gnanajobitha, G; Malarkodi, C; Sivakavinesan, M; Annadurai, G

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time.

  20. Molecular weight dependence of the physical properties of protonated polyaniline films and fibers

    Science.gov (United States)

    Adams, Phillip N.; Bowman, Danielle; Brown, Lori; Yang, Dali; Mattes, Benjamin R.

    2001-07-01

    Polyaniline, (PANI) in the form of emeraldine base, was synthesized by polymerizing aniline in acid solutions at different sub-zero temperatures to give a range of molecular weights between 100,000 and 300,000 gmol-1. Molecular weights were measured using gel permeation chromatography (GPC). The polymers were formed into solvent-cast films using an acid processing technique, involving 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) as the solvating/protonating acid group and dichloroacetic acid (DCA) plus formic acid (FA) as the solvent. The dried, free-standing films were stretched by drawing over a hot pin to align the polymer chains. Fibers were prepared by spinning more concentrated solutions into a butanone coagulation bath. Conductivity measurements were then made on the drawn films and fibers, and tensile test measurements performed to determine the peak stress and modulus of the drawn films and fibers. The reaction conditions under which the different polyanilines were synthesized, and their molecular weight, were found to have a definite effect upon both the electrical and mechanical properties of the drawn films and fibers. The drawn films and fibers can be used as mechanical actuators.

  1. Extraordinarily High Conductivity of Stretchable Fibers of Polyurethane and Silver Nanoflowers.

    Science.gov (United States)

    Ma, Rujun; Kang, Byeongguk; Cho, Suik; Choi, Minjun; Baik, Seunghyun

    2015-11-24

    Stretchable conductive composites have received considerable attention recently, and they should have high conductivity and mechanical strength. Here we report highly conductive stretchable fibers synthesized by the scalable wet spinning process using flower-shaped silver nanoparticles with nanodisc-shaped petals (Ag nanoflowers) and polyurethane. An extraordinarily high conductivity (41,245 S cm(-1)) was obtained by Ag nanoflowers, which is 2 orders of magnitude greater than that of fibers synthesized using spherical Ag nanoparticles. This was due to the enhanced surface area and vigorous coalescence of nanodisc-shaped petals during the curing process. There was a trade-off relationship between conductivity and stretchability, and the maximum rupture strain was 776%. An analytical model revealed that the enhanced adhesion between Ag nanoflowers and polyurethane provided a high Young's modulus (731.5 MPa) and ultimate strength (39.6 MPa) of the fibers. The fibers exhibited an elastic property after prestretching, and the resistance change of weft-knitted fabric was negligible up to 200% strain. The fibers with extraordinarily high conductivity, stretchability, and mechanical strength may be useful for wearable electronics applications.

  2. Mechanism of the industrial enterprises marketing communication synthesized effect formation

    Directory of Open Access Journals (Sweden)

    Ya.O. Tymokhina

    2014-09-01

    Full Text Available The aim of the article. The main purpose of the article is to propose mechanism of the industrial enterprises marketing communication (MC synthesized effect formation. An indispensable component of MC mechanism synthesized effect of industrial enterprise is the legislation that governs use of synthesized marketing communications and obtaines synthesized effect from using them. It can be divided into three groups: legislation that regulates entrepreneurial activities, legislation governing communication activities, legislation governing innovation activities. Legislation of Ukraine regulating communication activities needs to be clarified in regulation of using the latest MC tools, features of their combination, rules of their using and order of action in violation case of applicable law. The results of the analysis. Any economic activity of enterprises governed by principles that are divided into general and specific by the level of coverage. The proposed set of formation principles of synthesized effect are principles of systematic using that focus on the result and periodicity which refer to general. Within the principle of periodicity it should consider principles that characterize each level of management that are such principles as using synthesis, using synergy and complexity. Functions of synthesized effect that are subject to general principles of economic analysis are: searching, score, analysis and accounting. Essence of specific features of MC synthesized effect consists the following positions: planning function, integration function, communicative function, synthesis implementation function. Mechanism formation MC synthesized effect of industrial enterprise is a set of systems that are used in process of its creation by management levels that reflects subject-object relationship between these systems. Input elements system form factors of external and internal environment, information about which enterprise collects through market

  3. In-fiber integrated chemiluminiscence online optical fiber sensor.

    Science.gov (United States)

    Yang, Xinghua; Yuan, Tingting; Yang, Jun; Dong, Biao; Liu, Yanxin; Zheng, Yao; Yuan, Libo

    2013-09-01

    We report an in-fiber integrated chemiluminiscence (CL) sensor based on a kind of hollow optical fiber with a suspended inner core. The path of microfluid is realized by etching microholes for inlets and outlets on the surface of the optical fiber without damaging the inner core and then constructing a melted point beside the microhole of the outlet. When samples are injected into the fiber, the liquids can be fully mixed and form steady microflows. Simultaneously, the photon emitted from the CL reaction is efficiently coupled into the core and can be detected at the end of the optical fiber. In this Letter, the concentration of H2O2 samples is analyzed through the emission intensity of the CL reaction among H2O2, luminol, K3Fe(CN)6, and NaOH in the optical fiber. The linear sensing range of 0.1-4.0 mmol/L of H2O2 concentration is obtained. The emission intensity can be determined within 400 ms at a total flow rate of 150 μL/min. Significantly, this work presents the information of developing in-fiber integrated online analyzing devices based on optical methods.

  4. Optical fiber crossbar switch

    Science.gov (United States)

    Kilcoyne, Michael K.; Beccue, Stephen M.; Brar, Berinder; Robinson, G.; Pedrotti, Kenneth D.; Haber, William A.

    1990-07-01

    Advances in high performance computers and signal processing systems have led to parallel system architectures. The main limitation in achieving the performance expected of these parallel systems has been the realization of an efficient means to interconnect many processors into a effective parallel system. Electronic interconnections have proved cumbersome, costly and ineffective. The Optical Fiber Crossbar Switch (OFCS) is a compact low power, multi-gigahertz bandwidth multi-channel switch which can be used in large scale computer and telecommunication applications. The switch operates in the optical domain using GaAs semiconductor lasers to transmit wideband multiple channel optical data over fiber optic cables. Recently, a 32 X 32 crossbar switching system was completed and demonstrated. Error free performance was obtained at a data bandwidth of 410 MBPS, using a silicon switch IC. The switch can be completely reconfigured in less than 50 nanoseconds under computer control. The fully populated OFCS has the capability to handle 12.8 gigabits per second (GBPS) of data while switching this data over 32 channels without the loss of a single bit during switching. GaAs IC technology has now progressed to the point that 16 X 16 GaAs based crossbar switch Ics are available which have increased the data bandwidth capability to 2.4 GBPS. The present optical interfaces are integrated GaAs transmitter drivers, GaAs lasers, and integrated GaAs optical receivers with data bandwidths exceeding 2.4 GBPS. A system using all Ill-V switching and optoelectronic components is presently under development for both NASA and DoD programs. The overall system is designed to operate at 1.3 GBPS. It is expected that these systems will find wide application in high capacity computing systems based on parallel microprocessor architecture which require high data bandwidth communication between processors. The OFCS will also have application in commercial optical telecommunication systems

  5. Bonding Properties of Basalt Fiber and Strength Reduction According to Fiber Orientation

    OpenAIRE

    Jeong-Il Choi; Bang Yeon Lee

    2015-01-01

    The basalt fiber is a promising reinforcing fiber because it has a relatively higher tensile strength and a density similar to that of a concrete matrix as well as no corrosion possibility. This study investigated experimentally the bonding properties of basalt fiber with cementitious material as well as the effect of fiber orientation on the tensile strength of basalt fiber for evaluating basalt fiber’s suitability as a reinforcing fiber. Single fiber pullout tests were performed and then th...

  6. Continuously tunable wideband semiconductor fiber-ring laser

    Science.gov (United States)

    Mao, Xuefeng; Zhao, Shiwei; Yuan, Suzhen; Wang, Xiaofa; Zheng, Peichao

    2017-08-01

    We demonstrate a wideband tunable semiconductor fiber-ring laser that can be continuously tuned from 1498 nm to 1623 nm. The proposed laser uses a semiconductor optical amplifier (SOA) as a gain medium and a fiber Fabry-Perot tunable filter as a selective wavelength filter. The optimized drive current of the SOA and the output coupling ratio are obtained by experimental research. This laser has a simple configuration, low threshold, flat laser output power and high optical signal-to-noise ratio.

  7. Improved biomass degradation using fungal glucuronoyl-esterases-hydrolysis of natural corn fiber substrate

    DEFF Research Database (Denmark)

    d'Errico, Clotilde; Börjesson, Johan; Ding, Hanshu

    2016-01-01

    between glucuronic acids in xylans and lignin alcohols. By means of synthesized complex LCC model substrates we provide kinetic data suggesting a preference of fungal GEs for esters of bulky arylalkyl alcohols such as ester LCCs. Furthermore, using natural corn fiber substrate we report the first examples...... of improved degradation of lignocellulosic biomass by the use of GEs. Improved C5 sugar, glucose and glucuronic acid release was observed when heat pretreated corn fiber was incubated in the presence of GEs from Cerrena unicolor and Trichoderma reesei on top of different commercial cellulase...

  8. Impacts of Temperature Disparity on Surface Modification of Short Jute Fiber-Reinforced Epoxy Composites

    Science.gov (United States)

    Basak, Reshmi; Choudhury, P. L.; Pandey, K. M.

    2017-08-01

    Chase for manufacturing composite materials without negotiating on the physio-mechanical performance has been prevailing since long. Short jute fiber-reinforced epoxy based composites are prepared and their mechanical properties have been analyzed. The fibers are peroxide-silane treated under varying conditions of temperature from low to high. Results display that the jute composites set at higher temperature values indicate higher values of mechanical properties compared to those synthesized under lower temperature range. The same can be cited for liquid retaining capacity.

  9. Green Fiber Bottle

    DEFF Research Database (Denmark)

    Didone, Mattia; Tosello, Guido

    their impact on the environment, especially the oceans. For example, the life span of a plastic bottle in the ocean is 500 years, and during its degradation, the plastic is reduced to micro pieces, which causes the starvation of several marine animals. The new bottle is completely made from molded paper pulp...... technologies, the manufacturing technology for the production of the bottle has to offer the possibility of significant energy savings. Molded pulp products are made from wood fibers dispersed in water, and then they are formed, drained and dried. A relatively large quantity of resources (i.e. energy and time......) is consumed during the drying process. It is in this process stage that an innovative way of drying the products can be exploited by using the concept of impulse drying. Impulse drying is an advance drying technique in which water is removed from a wet paper pulp by the combination of mechanical pressure...

  10. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  11. Fiber optic hydrogen sensor

    Energy Technology Data Exchange (ETDEWEB)

    Butler, M.A.; Sanchez, R.; Dulleck, G.R.

    1996-05-01

    This report covers the development of fiber optic hydrogen and temperature sensors for monitoring dissolved hydrogen gas in transformer oil. The concentration of hydrogen gas is a measure of the corona and spark discharge within the transformer and reflects the state of health of the transformer. Key features of the instrument include use of palladium alloys to enhance hydrogen sensitivity, a microprocessor controlled instrument with RS-232, liquid crystal readout, and 4-20 ma. current loop interfaces. Calibration data for both sensors can be down loaded to the instrument through the RS-232 interface. This project was supported by the Technology Transfer Initiative in collaboration with J. W. Harley, Inc. through the mechanism of a cooperative research and development agreement (CRADA).

  12. Optical fiber synaptic sensor

    Science.gov (United States)

    Pisarchik, A. N.; Jaimes-Reátegui, R.; Sevilla-Escoboza, R.; García-Lopez, J. H.; Kazantsev, V. B.

    2011-06-01

    Understanding neuron connections is a great challenge, which is needed to solve many important problems in neurobiology and neuroengineering for recreation of brain functions and efficient biorobotics. In particular, a design of an optical synapse capable to communicate with neuron spike sequences would be crucial to improve the functionality of neuromimmetic networks. In this work we propose an optical synaptic sensor based on an erbium-doped fiber laser driven by a FitzHung-Nagumo electronic neuron, to connect with another electronic neuron. Two possible optical synaptic configurations are analyzed for optoelectronic coupling between neurons: laser cavity loss modulation and pump laser modulation. The control parameters of the proposed optical synapse provide additional degrees of flexibility to the neuron connection traditionally controlled only by coupling strengths in artificial networks.

  13. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, Anelia [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States); Booth, Samuel [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States)

    2016-09-01

    Carbon fiber (CF), known also as graphite fiber, is a lightweight, strong, and flexible material used in both structural (load-bearing) and non-structural applications (e.g., thermal insulation). The high cost of precursors (the starting material used to make CF, which comes predominately from fossil sources) and manufacturing have kept CF a niche market with applications limited mostly to high-performance structural materials (e.g., aerospace). Alternative precursors to reduce CF cost and dependence on fossil sources have been investigated over the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic sugars. The purpose of this study is to provide a comprehensive overview of CF precursors from biomass and their market potential. We examine the potential CF production from these precursors, the state of technology and applications, and the production cost (when data are available). We discuss their advantages and limitations. We also discuss the physical properties of biomass-based CF, and we compare them to those of polyacrylonitrile (PAN)-based CF. We also discuss manufacturing and end-product considerations for bio-based CF, as well as considerations for plant siting and biomass feedstock logistics, feedstock competition, and risk mitigation strategies. The main contribution of this study is that it provides detailed technical and market information about each bio-based CF precursor in one document while other studies focus on one precursor at a time or a particular topic (e.g., processing). Thus, this publication allows for a comprehensive view of the CF potential from all biomass sources and serves as a reference for both novice and experienced professionals interested in CF production from alternative sources.

  14. Photonic bandgap fiber bundle spectrometer

    CERN Document Server

    Hang, Qu; Syed, Imran; Guo, Ning; Skorobogatiy, Maksim

    2010-01-01

    We experimentally demonstrate an all-fiber spectrometer consisting of a photonic bandgap fiber bundle and a black and white CCD camera. Photonic crystal fibers used in this work are the large solid core all-plastic Bragg fibers designed for operation in the visible spectral range and featuring bandgaps of 60nm - 180nm-wide. 100 Bragg fibers were chosen to have complimentary and partially overlapping bandgaps covering a 400nm-840nm spectral range. The fiber bundle used in our work is equivalent in its function to a set of 100 optical filters densely packed in the area of ~1cm2. Black and white CCD camera is then used to capture spectrally "binned" image of the incoming light at the output facet of a fiber bundle. To reconstruct the test spectrum from a single CCD image we developed an algorithm based on pseudo-inversion of the spectrometer transmission matrix. We then study resolution limit of this spectroscopic system by testing its performance using spectrally narrow test peaks (FWHM 5nm-25nm) centered at va...

  15. Microfabrication of fiber optic scanners

    Science.gov (United States)

    Fauver, Mark; Crossman-Bosworth, Janet L.; Seibel, Eric J.

    2002-06-01

    A cantilevered optical fiber is micromachined to function as a miniature resonant opto-mechanical scanner. By driving the base of the cantilevered fiber at a resonance frequency using a piezoelectric actuator, the free end of the cantilever beam becomes a scanned light source. The fiber scanners are designed to achieve wide field-of-view (FOV) and high scan frequency. We employ a non-linearly tapered profile fiber to achieve scan amplitudes of 1 mm at scan frequencies above 20 KHz. Scan angles of over 120 degree(s) (full angle) have been achieved. Higher order modes are also employed for scanning applications that require compactness while maintaining large angular FOV. Etching techniques are used to create the non-linearly tapered sections in single mode optical fiber. Additionally, micro-lenses are fabricated on the tips of the etched fibers, with lens diameters as small as 15 microns. Such lenses are capable of reducing the divergence angle of the emitted light to 5 degree(s) (full angle), with greater reduction expected by employing novel lens shaping techniques. Microfabricated optical fiber scanners have display applications ranging from micro-optical displays to larger panoramic displays. Applications for micro-image acquisition include small barcode readers to medical endoscopes.

  16. Forensic Fiber Examination and Analysis.

    Science.gov (United States)

    Hauck, M M

    2005-01-01

    Fiber evidence suffers from the same misperception as many other types of trace evidence, that it is weak in its significance. Despite this pejorative perception, textiles make excellent evidence because of their presence in our daily lives and the variations they demonstrate. Fibers from the textiles in our and others' environments transfer from surface to surface and variously persist. Textile fibers are produced with specific raw materials, production methods, and postproduction alterations that create this variety. The distribution and use of the fibers add to their distinctive significance. The number of methods used in analysis helps to define and identify the fibers. Millions of color shades are possible in textiles and yet color analysis is not a universal technique in forensic laboratories. Transfer study after transfer study demonstrates the rarity of finding unrelated fibers at random that exhibit the same microscopic characteristics and optical properties. Examples from casework also demonstrate the usefulness of forensic textile fiber analysis in demonstrating probative associations in criminal investigations. Additional work needs to be done to fortify and support these conclusions and provide the verification necessary to remove the taint of "could have".

  17. Distributed Fiber Optic Gas Sensing for Harsh Environment

    Energy Technology Data Exchange (ETDEWEB)

    Juntao Wu

    2008-03-14

    This report summarizes work to develop a novel distributed fiber-optic micro-sensor that is capable of detecting common fossil fuel gases in harsh environments. During the 32-month research and development (R&D) program, GE Global Research successfully synthesized sensing materials using two techniques: sol-gel based fiber surface coating and magnetron sputtering based fiber micro-sensor integration. Palladium nanocrystalline embedded silica matrix material (nc-Pd/Silica), nanocrystalline palladium oxides (nc-PdO{sub x}) and palladium alloy (nc-PdAuN{sub 1}), and nanocrystalline tungsten (nc-WO{sub x}) sensing materials were identified to have high sensitivity and selectivity to hydrogen; while the palladium doped and un-doped nanocrystalline tin oxide (nc-PdSnO{sub 2} and nc-SnO{sub 2}) materials were verified to have high sensitivity and selectivity to carbon monoxide. The fiber micro-sensor comprises an apodized long-period grating in a single-mode fiber, and the fiber grating cladding surface was functionalized by above sensing materials with a typical thickness ranging from a few tens of nanometers to a few hundred nanometers. GE found that the morphologies of such sensing nanomaterials are either nanoparticle film or nanoporous film with a typical size distribution from 5-10 nanometers. nc-PdO{sub x} and alloy sensing materials were found to be highly sensitive to hydrogen gas within the temperature range from ambient to 150 C, while nc-Pd/Silica and nc-WO{sub x} sensing materials were found to be suitable to be operated from 150 C to 500 C for hydrogen gas detection. The palladium doped and un-doped nc-SnO{sub 2} materials also demonstrated sensitivity to carbon monoxide gas at approximately 500 C. The prototyped fiber gas sensing system developed in this R&D program is based on wavelength-division-multiplexing technology in which each fiber sensor is identified according to its transmission spectra features within the guiding mode and cladding modes. The

  18. All-Fiber Components for Micro-Structured Fibers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose new concepts for developing components for high performance space based Lidar systems. While it is generally recognized that photonic crystal fiber...

  19. Multiplexed displacement fiber sensor using thin core fiber exciter.

    Science.gov (United States)

    Chen, Zhen; Hefferman, Gerald; Wei, Tao

    2015-06-01

    This letter reports a multiplexed optical displacement sensor using a thin core fiber (TCF) exciter. The TCF exciter is followed by a stripped single mode optical fiber. A small section of buffer is used as the movable component along the single mode fiber. Ultra-weak cladding mode reflection (coating boundary. The position change of the movable buffer segment results in a delay change of the cladding mode reflection. Thus, it is a measure of the displacement of the buffer segment with respect to the glass fiber. The insertion loss of one sensor was measured to be less than 3 dB. A linear relationship was evaluated between the measurement position and absolute position of the moving actuator. Multiplexed capability was demonstrated and no cross talk was found between the sensors.

  20. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...

  1. Carbon Fiber Biocompatibility for Implants

    OpenAIRE

    Richard Petersen

    2016-01-01

    Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-rein...

  2. Campus fiber optic enterprise networks

    Science.gov (United States)

    Weeks, Richard A.

    1991-02-01

    The proliferation of departmental LANs in campus environments has driven network technology to the point where construction of token ring fiber-optic backbone systems is now a cost-effective alternative. This article will discuss several successful real life case history applications of token ring fiber in a campus setting each with unique distance and load factor requirements. It is hoped that these examples will aid in the understanding planning and implementation of similar installations. It will also attempt to provide important information on the emerging Fiber Distributed Data Interface (FDDI) standard.

  3. Evaluation of green synthesized silver nanoparticles against parasites.

    Science.gov (United States)

    Marimuthu, Sampath; Rahuman, Abdul Abdul; Rajakumar, Govindasamy; Santhoshkumar, Thirunavukkarasu; Kirthi, Arivarasan Vishnu; Jayaseelan, Chidambaram; Bagavan, Asokan; Zahir, Abdul Abduz; Elango, Gandhi; Kamaraj, Chinnaperumal

    2011-06-01

    Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and eco-friendly reducing and capping agents. The present study was based on assessments of the antiparasitic activities to determine the efficacies of synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Mimosa pudica Gaertn (Mimosaceae) against the larvae of malaria vector, Anopheles subpictus Grassi, filariasis vector Culex quinquefasciatus Say (Diptera: Culicidae), and Rhipicephalus (Boophilus) microplus Canestrini (Acari: Ixodidae). Parasite larvae were exposed to varying concentrations of aqueous extract of M. pudica and synthesized AgNPs for 24 h. AgNPs were rapidly synthesized using the leaf extract of M. pudica and the formation of nanoparticles was observed within 6 h. The results recorded from UV-vis spectrum, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of A. subpictus, C. quinquefasciatus, and R. microplus (LC(50) = 13.90, 11.73, and 8.98 mg/L, r (2) = 0.411, 0.286, and 0.479), respectively. This is the first report on antiparasitic activity of the plant extract and synthesized AgNPs.

  4. A Large Area Fiber Optic Gyroscope on multiplexed fiber network

    OpenAIRE

    Clivati, Cecilia; Calonico, Davide; Costanzo, Giovanni A.; Mura, Alberto; Pizzocaro, Marco; Levi, Filippo

    2012-01-01

    We describe a fiber optical gyroscope based on the Sagnac effect realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km^2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about 1e-8 (rad/s)/sqrt(Hz), thus approaching ring laser gyroscopes without using narrow-linewidth laser nor sophisticated optics. The proposed gyroscope is sensitive enough for seismic applications, opening new possibilities for this kind of optical f...

  5. Silicon photonics for multicore fiber communication

    DEFF Research Database (Denmark)

    Ding, Yunhong; Kamchevska, Valerija; Dalgaard, Kjeld

    2016-01-01

    We review our recent work on silicon photonics for multicore fiber communication, including multicore fiber fan-in/fan-out, multicore fiber switches towards reconfigurable optical add/drop multiplexers. We also present multicore fiber based quantum communication using silicon devices....

  6. Digital signal processing for fiber nonlinearities [Invited

    DEFF Research Database (Denmark)

    Cartledge, John C.; Guiomar, Fernando P.; Kschischang, Frank R.

    2017-01-01

    This paper reviews digital signal processing techniques that compensate, mitigate, and exploit fiber nonlinearities in coherent optical fiber transmission systems......This paper reviews digital signal processing techniques that compensate, mitigate, and exploit fiber nonlinearities in coherent optical fiber transmission systems...

  7. Climbing fiber signaling and cerebellar gain control

    NARCIS (Netherlands)

    G. Ohtsuki (Gen); C. Piochon (Claire); C.R.W. Hansel (Christian)

    2009-01-01

    textabstractThe physiology of climbing fiber signals in cerebellar Purkinje cells has been studied since the early days of electrophysiology. Both the climbing fiber-evoked complex spike and the role of climbing fiber activity in the induction of long-term depression (LTD) at parallel fiber-Purkinje

  8. Generation of non-overlapping fiber architecture

    DEFF Research Database (Denmark)

    Chapelle, Lucie; Lévesque, M.; Brøndsted, Povl

    2015-01-01

    of overlapping sphero-cylinders. At the end of the first step, a system of overlapping fibers is obtained. In order to obtain a hard-core configuration where fibers cannot overlap other fibers, we use an iterative method called the force-biased algorithm. It applies virtual forces on each point of the fiber...

  9. Influence of fiber quality on draftometer measurements

    Science.gov (United States)

    Fiber-to-fiber and fiber-to-machine friction play an important role in determining textile processing efficiency and end-product quality. A process, known as drafting, is used to control the attenuation of the fiber mass being processed in carding, drawing and spinning. The amount of attenuation t...

  10. Low-Loss Fiber De-Multiplexers

    Institute of Scientific and Technical Information of China (English)

    Nan-Kuang; Chen; Sien; Chi; Shiao-Min; Tseng

    2003-01-01

    Reported are fiber de-multiplexers based on side-polished fibers with a long interaction length and intra-core fiber Bragg gratings. In conjunction with the silicon processing technologies, we demonstrate fiber filters and advantages of our approaches are addressed.

  11. Methods of producing continuous boron carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, John E.; Griffith, George W.

    2015-12-01

    Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

  12. Use of optical fibers in spectrophotometry

    Science.gov (United States)

    Ramsey, Lawrence W.

    1988-01-01

    The use of single or small numbers of fiber optic fibers in astronomical spectroscopy with the goal of greater spectrophotometric and radial velocity accuracy is discussed. The properties of multimode step index fibers which are most important for this application are outlined, as are laboratory tests of currently available fibers.

  13. Adsorption characteristics of activated carbon hollow fibers

    OpenAIRE

    2009-01-01

    Carbon hollow fibers were prepared with regenerated cellulose or polysulfone hollow fibers by chemical activation using sodium phosphate dibasic followed by the carbonization process. The activation process increases the adsorption properties of fibers which is more prominent for active carbone fibers obtained from the cellulose precursor. Chemical activation with sodium phosphate dibasic produces an active carbon material with both mesopores and micropores.

  14. A temperature-regulating fiber made of PEG-based smart copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qinghao; Hu, Jinlian [Shape Memory Textile Center, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China)

    2008-10-15

    A poly(ethylene glycol) (PEG)-based thermoplastic shape memory polyurethane was synthesized via bulk polymerization. The corresponding fiber, as a temperature-regulating fiber, was fabricated via melt spinning. The prepared 100-dtex fiber had a tenacity of 0.7 cN/dtex and breaking elongation of about 488%. The fiber's phase change behaviors, crystalline morphology, dynamic mechanical properties, and temperature-resistant performance were investigated using polarizing optical microscopy, differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetry. The PEG soft segment phase transfer between crystalline and amorphous states resulted in heat storage and release. The hydrogen-bonded hard segment phase, serving as 'physical cross-links,' restricted the free movement of soft segments, hence at temperatures above the PEG phase melting transition, the fiber still possessed certain mechanical strength. The differential scanning calorimetry results indicated that the fiber had large latent heat-storage capacity of about 100 J/g with a crystallizing temperature of 20.9 C and a melting temperature of 44.7 C. The dynamic mechanical analysis results showed that the fiber has a plateau elastic modulus in the region above the PEG phase melting transition and below 160 C. The thermogravimetry results suggested that the fiber had a much broader applicable temperature range compared to pure PEG. The thermo-mechanical cyclic tensile testing results showed that the fiber had good shape memory effect with the shape fixity ratio more than 85.8% and the recovery ratio above 95.4%. (author)

  15. Fiber pull-out test and single fiber fragmentation test - analysis and modelling

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Lilholt, Hans

    2016-01-01

    for fiber/matrix debonding and a frictional sliding shear stress. Results for the debond length and fiber debond displacement are compared with results from similar models for single fiber pull-out experiments where the specimen is gripped at the end opposite to the end where the fiber is pulling......-out and with results for a single fiber fragmentation test....

  16. Soft capacitor fibers for electronic textiles

    Science.gov (United States)

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-09-01

    A highly flexible, conductive polymer-based fiber with high electric capacitance is reported. The fiber is fabricated using fiber drawing method, where a multimaterial macroscopic preform is drawn into a submillimeter capacitor microstructured fiber. A typical measured capacitance per unit length of our fibers is 60-100 nF/m which is about 3 orders magnitude higher than that of a coaxial cable of a comparable diameter. The fiber has a transverse resistivity of 5 kΩ m. Softness, lightweight, absence of liquid electrolyte, and ease of scalability to large production volumes make the fibers interesting for various smart textile applications.

  17. Xyloglucan breakdown during cotton fiber development.

    Science.gov (United States)

    Tokumoto, Hayato; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    2003-11-01

    Cotton (Gossypium herbaceum L.) fibers elongated almost linearly up to about 20 days post anthesis. The molecular mass of xyloglucans in fiber cell walls decreased gradually during the elongation stage. When enzymatically active (native) cell wall preparations of fibers were autolyzed, the molecular mass of xyloglucans decreased. The decrease was most prominent in wall preparations obtained from the rapidly elongating fibers. The xyloglucan-degrading activity was recovered from the fiber cell walls with 3 mol/L NaCl, and the activity was high at the stages in which fibers elongated vigorously. These results suggest the possible involvement of xyloglucan metabolism in the regulation of cotton fiber elongation.

  18. Matters of fiber size and myonuclear domain

    DEFF Research Database (Denmark)

    Karlsen, Anders; Couppé, Christian; Andersen, Jesper L.;

    2015-01-01

    INTRODUCTION: The relationship between fiber size and myonuclear content is understood poorly. METHODS: Biopsy cross-sections from young and old trained and untrained healthy individuals were analyzed for fiber area and myonuclei, and 2 fiber size-dependent cluster analyses were performed. RESULTS......: Comparing fibers of similar size, no effect of training or age was found for myonuclear domain. There was a linear relationship between fiber area and myonuclei per fiber (r=0.99; Pfiber area and domain (r=0.97-0.99; P... in fibers fibers below 3,000 μm(2) was observed in the old. DISCUSSION: These findings suggest that age-related reductions in myonuclear domain size could be explained by a larger proportion of small fibers and highlight the usefulness of fiber size...

  19. [Classification and the composition of food fibers].

    Science.gov (United States)

    Bezhanidze, I Z; Alasaniia, N Sh; Kontselidze, L A; Kharazi, N A; Bezhanidze, N V

    2009-06-01

    Fiber promotes the contractions that keep food moving through the intestine. Also, high-fiber foods expand the inside walls of the colon and eases the passage of waste. The food and fiber research was conducted. In the article, the classification and the composition of food fibers are presented. Multifunctional properties of food fiber in the process of digestion are discussed. The physiological value of food fibers for the human organism is stressed. Diets high in fiber during the entire life are recommended. If a person can't consume enough fiber in diet alone, certain stool softening and bulking agents are recommended. They can be very useful in preventing and treating digestive tract disorders. The analysis of high fiber food sources and world production and consumption of food fiber is also presented.

  20. Ethanol extraction of phytosterols from corn fiber

    Science.gov (United States)

    Abbas, Charles; Beery, Kyle E.; Binder, Thomas P.; Rammelsberg, Anne M.

    2010-11-16

    The present invention provides a process for extracting sterols from a high solids, thermochemically hydrolyzed corn fiber using ethanol as the extractant. The process includes obtaining a corn fiber slurry having a moisture content from about 20 weight percent to about 50 weight percent solids (high solids content), thermochemically processing the corn fiber slurry having high solids content of 20 to 50% to produce a hydrolyzed corn fiber slurry, dewatering the hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, washing the residual corn fiber, dewatering the washed, hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, and extracting the residual corn fiber with ethanol and separating at least one sterol.