WorldWideScience

Sample records for hollow fiber filter

  1. 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...

  2. Hollow-Core Fiber Lamp

    Science.gov (United States)

    Yi, Lin (Inventor); Tjoelker, Robert L. (Inventor); Burt, Eric A. (Inventor); Huang, Shouhua (Inventor)

    2016-01-01

    Hollow-core capillary discharge lamps on the millimeter or sub-millimeter scale are provided. The hollow-core capillary discharge lamps achieve an increased light intensity ratio between 194 millimeters (useful) and 254 millimeters (useless) light than conventional lamps. The capillary discharge lamps may include a cone to increase light output. Hollow-core photonic crystal fiber (HCPCF) may also be used.

  3. A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

    OpenAIRE

    Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

    2014-01-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distributi...

  4. A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

    Science.gov (United States)

    Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

    2014-01-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

  5. A cluster randomized controlled trial to reduce childhood diarrhea using hollow fiber water filter and/or hygiene-sanitation educational interventions.

    Science.gov (United States)

    Lindquist, Erik D; George, C M; Perin, Jamie; Neiswender de Calani, Karen J; Norman, W Ray; Davis, Thomas P; Perry, Henry

    2014-07-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15-0.30) for the filter arm and 0.27 (95% CI = 0.22-0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59-0.86). © The American Society of Tropical Medicine and Hygiene.

  6. Oriented Fiber Filter Media

    OpenAIRE

    R. Bharadwaj; A. Patel, S. Chokdeepanich, Ph.D.; G.G. Chase, Ph.D.

    2008-01-01

    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 t...

  7. Ceramic fiber reinforced filter

    Science.gov (United States)

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  8. 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.

  9. Transmission properties of hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Falk, Charlotte Ijeoma; Hald, Jan; Petersen, Jan C.

    2010-01-01

    Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers.......Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers....

  10. Hollow-Fiber Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

    2013-01-01

    The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.

  11. Hollow fiber bioreactor technology for tissue engineering applications.

    Science.gov (United States)

    Eghbali, Hadis; Nava, Michele M; Mohebbi-Kalhori, Davod; Raimondi, Manuela T

    2016-01-01

    Hollow fiber bioreactors are the focus of scientific research aiming to mimic physiological vascular networks and engineer organs and tissues in vitro. The reason for this lies in the interesting features of this bioreactor type, including excellent mass transport properties. Indeed, hollow fiber bioreactors allow limitations to be overcome in nutrient transport by diffusion, which is often an obstacle to engineer sizable constructs in vitro. This work reviews the existing literature relevant to hollow fiber bioreactors in organ and tissue engineering applications. To this purpose, we first classify the hollow fiber bioreactors into 2 categories: cylindrical and rectangular. For each category, we summarize their main applications both at the tissue and at the organ level, focusing on experimental models and computational studies as predictive tools for designing innovative, dynamic culture systems. Finally, we discuss future perspectives on hollow fiber bioreactors as in vitro models for tissue and organ engineering applications.

  12. 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...

  13. Hollow fiber membranes and methods for forming same

    Science.gov (United States)

    Bhandari, Dhaval Ajit; McCloskey, Patrick Joseph; Howson, Paul Edward; Narang, Kristi Jean; Koros, William

    2016-03-22

    The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

  14. Hollow-core fibers for high power pulse delivery

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Lyngsø, Jens K.; Jakobsen, Christian

    2016-01-01

    We investigate hollow-core fibers for fiber delivery of high power ultrashort laser pulses. We use numerical techniques to design an anti-resonant hollow-core fiber having one layer of non-touching tubes to determine which structures offer the best optical properties for the delivery of high power......-core fiber. The three fibers are characterized experimentally for the delivery of 22 picosecond pulses at 1032nm. We demonstrate flexible, diffraction limited beam delivery with output average powers in excess of 70W. (C) 2016 Optical Society of America...

  15. Polyazole hollow fiber membranes for direct contact membrane distillation

    KAUST Repository

    Maab, Husnul

    2013-08-07

    Porous hollow fiber membranes were fabricated from fluorinated polyoxadiazole and polytriazole by a dry-wet spinning method for application in desalination of Red Sea water by direct contact membrane distillation (DCMD). The data were compared with commercially available hollow fiber MD membranes prepared from poly(vinylidene fluoride). The membranes were characterized by electron microscopy, liquid entry pressure (LEP), and pore diameter measurements. Finally, the hollow fiber membranes were tested for DCMD. Salt selectivity as high as 99.95% and water fluxes as high as 35 and 41 L m -2 h-1 were demonstrated, respectively, for polyoxadiazole and polytriazole hollow fiber membranes, operating at 80 C feed temperature and 20 C permeate. © 2013 American Chemical Society.

  16. Hollow fiber adsorbents for CO2 capture: Kinetic sorption performance

    KAUST Repository

    Lively, Ryan P.

    2011-07-01

    We describe a CO 2 capture platform based on hollow polymeric fibers with sorbent particles embedded in the porous fiber wall for post-combustion CO 2 capture. These fibers are intended for use in a rapid temperature swing adsorption (RTSA) process. The RTSA system utilizes the hollow fiber morphology by flowing cooling water on the bore-side of the fibers during sorption to prevent temperature rise associated with the sorption enthalpy. Steam or hot water is flowed through the bores during desorption to desorb CO 2 rapidly. To minimize material transfer between the bore and the fiber wall, a dense Neoprene ® lumen layer is cast on the bore-side of the fiber wall. In this paper, the key sorption step and associated kinetic resistances for the uncooled fibers are examined and evaluated for this portion of the RTSA process. Chopped fibers in a packed bed, as well as fibers assembled into a parallel flow module, have been tested in a simulated flue gas stream. Kinetic limitations in the hollow fiber modules are largely overcome by increasing the superficial gas velocity and the fiber packing in the module-indicating that film diffusion is the controlling mass transfer limitation in the fiber system. The un-cooled fiber modules lose apparent capacity as superficial velocities are increased, likely indicating non-isothermal operation, whereas the actively-cooled fibers in the packed bed maintain apparent capacity at all flowrates studied. © 2011 Elsevier B.V.

  17. Highly efficient fluorescence sensing with hollow core photonic crystal fibers

    DEFF Research Database (Denmark)

    Smolka, Stephan; Barth, Michael; Benson, Oliver

    2008-01-01

    We investigate hollow core photonic crystal fibers for ultra-sensitive fluorescence detection by selectively infiltrating the central hole with fluorophores. Dye concentrations down to 10(-9) M can be detected using only nanoliter sample volumes.......We investigate hollow core photonic crystal fibers for ultra-sensitive fluorescence detection by selectively infiltrating the central hole with fluorophores. Dye concentrations down to 10(-9) M can be detected using only nanoliter sample volumes....

  18. Antiresonant hollow core fiber with seven nested capillaries

    DEFF Research Database (Denmark)

    Antonio-Lopez, Jose E.; Habib, Selim; Van Newkirk, Amy

    2016-01-01

    We report an antiresonant hollow core fiber formed of 7 non-touching capillaries with inner tubes. The fiber has a core diameter of ∼33μm and a core wall of ∼780nm of thickness. We demonstrate robust single mode operation at 1064nm and broad transmission bandwidth.......We report an antiresonant hollow core fiber formed of 7 non-touching capillaries with inner tubes. The fiber has a core diameter of ∼33μm and a core wall of ∼780nm of thickness. We demonstrate robust single mode operation at 1064nm and broad transmission bandwidth....

  19. Influence of air pressure on soliton formation in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Roberts, Peter John

    2009-01-01

    Abstract Soliton formation during dispersive compression of chirped few-picosecond pulses at the microjoule level in a hollow-core photonic bandgap (HC-PBG) fiber is studied by numerical simulations. Long-pass filtering of the emerging frequency-shifted solitons is investigated with the objective...... of obtaining pedestal-free output pulses. Particular emphasis is placed on the influence of the air pressure in the HC-PBG fiber. It is found that a reduction in air pressure enables an increase in the fraction of power going into the most redshifted soliton and also improves the quality of the filtered pulse...

  20. Soliton formation in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper

    2009-01-01

    The formation of solitons upon compression of linearly chirped pulses in hollow-core photonic bandgap fibers is investigated numerically. The dependence of soliton duration on the chirp and power of the input pulse and on the dispersion slope of the fiber is investigated, and the validity...... of an approximate scaling relation is tested. It is concluded that compression of input pulses of several ps duration and sub-MW peak power can lead to a formation of solitons with ∼100 fs duration and multi-megawatt peak powers. The dispersion slope of realistic hollow-core fibers appears to be the main obstacle...

  1. Confinement less spectral behavior in hollow-core Bragg fibers

    DEFF Research Database (Denmark)

    Foroni, M.; Passaro, D.; Poli, F.

    2007-01-01

    The influence of each cross-section geometric parameter on hollow-core Bragg fiber guiding properties has been numerically investigated. Fabricated fibers have been modeled, giving insight into the spectral behavior of the confinement loss. It has been verified that, by changing the amount...... of silica and air in the fiber cladding, it is possible to change the reflection conditions undergone by the field within the core, thus shifting the confinement loss spectrum....

  2. Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution

    Science.gov (United States)

    Qiu, Penghe; Mao, Chuanbin

    2010-01-01

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. Based on this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fibers. First, inorganic material such as silica with high affinity against the PVP could be deposited on the surface of the branched hollow PVP fibers to form branched hollow silica fibers. To extend the application of PVP self-assembly in templating the formation of hollow branched fibers, we then adopted a second approach where the PVP molecules bound to inorganic nanoparticles (using gold nanoparticles as a model) co-self-assemble with the free PVP molecules in an aqueous solution, resulting in the formation of the branched hollow fibers with the nanoparticles embedded in the PVP matrix constituting the walls of the fibers. Heating the resultant fibers above the glass transition temperature of PVP led to the formation of branched hollow gold fibers. Our work suggests that the self-assembly of the PVP molecules in the solution can serve as a general method for directing the formation of branched hollow inorganic fibers. The branched hollow fibers may find potential applications in microfluidics, artificial blood vessel generation, and tissue engineering. PMID:20158250

  3. Fabrication of Polyacrylonitrile Hollow Fiber Membranes from Ionic Liquid Solutions

    KAUST Repository

    Kim, Dooli

    2015-10-08

    The interest in green processes and products has increased to reduce the negative impact of many industrial processes to the environment. Solvents, which play a crucial role in the fabrication of membranes, need to be replaced by sustainable and less toxic solvent alternatives for commonly used polymers. The purpose of this study is the fabrication of greener hollow fiber membranes based on polyacrylonitrile (PAN), substituting dimethylformamide (DMF) by less toxic mixtures of ionic liquids (IL) and dimethylsulfoxide (DMSO). A thermodynamic analysis was conducted, estimating the Gibbs free energy of mixing to find the most convenient solution compositions. Hollow fiber membranes were manufactured and optimized. As a result, a uniform pattern and high porosity were observed in the inner surface of the membranes prepared from the ionic liquid solutions. The membranes were coated with a polyamide layer by interfacial polymerization the hollow fiber membranes were applied in forward osmosis experiments by using sucrose solutions as draw solution.

  4. Hollow core photonic crystal fiber based viscometer with Raman spectroscopy.

    Science.gov (United States)

    Horan, L E; Ruth, A A; Gunning, F C Garcia

    2012-12-14

    The velocity of a liquid flowing through the core of a hollow core photonic crystal fiber (driven by capillary forces) is used for the determination of a liquid's viscosity, using volumes of less than 10 nl. The simple optical technique used is based on the change in propagation characteristics of the fiber as it fills with the liquid of interest via capillary action, monitored by a laser source. Furthermore, the liquid filled hollow core photonic crystal fiber is then used as a vessel to collect Raman scattering from the sample to determine the molecular fingerprint of the liquid under study. This approach has a wide variety of indicative uses in cases where nano-liter samples are necessary. We use 10-12 cm lengths of hollow core photonic crystal fibers to determine the viscosity and Raman spectra of small volumes of two types of monosaccharides diluted in a phosphate buffer solution to demonstrate the principle. The observed Raman signal is strongest when only the core of the hollow core photonic crystal fiber is filled, and gradually decays as the rest of the fiber fills with the sample.

  5. Hollow-core photonic band gap fibers for particle acceleration

    Directory of Open Access Journals (Sweden)

    Robert J. Noble

    2011-12-01

    Full Text Available Photonic band gap (PBG dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller holes to confine the mode, forming a photonic crystal fiber in which modes exist in frequency passbands, separated by band gaps. The hollow core acts as a defect which breaks the crystal symmetry, and so-called defect, or trapped modes having frequencies in the band gap will only propagate near the defect. We describe the design of 2D hollow-core PBG fibers to support TM defect modes with high longitudinal fields and high characteristic impedance. Using as-built dimensions of industrially made fibers, we perform a simulation analysis of prototype PBG fibers with dimensions appropriate for speed-of-light TM modes.

  6. Hollow-Core Photonic Band Gap Fibers for Particle Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Robert J.; Spencer, James E.; /SLAC; Kuhlmey, Boris T.; /Sydney U.

    2011-08-19

    Photonic band gap (PBG) dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM) accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller holes to confine the mode, forming a photonic crystal fiber in which modes exist in frequency pass-bands, separated by band gaps. The hollow core acts as a defect which breaks the crystal symmetry, and so-called defect, or trapped modes having frequencies in the band gap will only propagate near the defect. We describe the design of 2-D hollow-core PBG fibers to support TM defect modes with high longitudinal fields and high characteristic impedance. Using as-built dimensions of industrially-made fibers, we perform a simulation analysis of the first prototype PBG fibers specifically designed to support speed-of-light TM modes.

  7. Hollow glass fibers in reinforcing glass ionomer cements.

    Science.gov (United States)

    Garoushi, Sufyan; Vallittu, Pekka; Lassila, Lippo

    2017-02-01

    This study investigated the reinforcing effect of hollow and solid discontinuous glass fiber fillers with two different loading fractions on select mechanical properties of conventional and resin modified glass ionomer cements (GICs). Experimental fiber reinforced GIC was prepared by adding discontinuous glass fiber (hollow/solid) of 0.5mm in length to the powder of commercial GICs (GC Fuji IX and II LC) with two different weight ratios (5 and 10wt%) using a high speed mixing machine. Fracture toughness, work of fracture, flexural strength, flexural modulus, compressive strength and diametral tensile strength were determined for each experimental and control material. The specimens (n=7) were wet stored (37°C for one day) before testing. Scanning electron microscopy was used to evaluate the microstructure of the experimental fiber reinforced GICs. Fiber length analysis was carried out to investigate the fiber length distribution of experimental GICs. The results were analyzed statistically using ANOVA followed by Tukey's post hoc test. Level of significance was set at 0.05. An increase in fracture toughness (280 and 200%) and flexural strength (170 and 140%) of hollow discontinuous glass fiber reinforced (10wt%) conventional and resin modified GICs respectively, were achieved compared to unreinforced materials (p0.05) between the fiber reinforced and unreinforced GICs. The use of hollow discontinuous glass fiber fillers with conventional and resin modified GIC matrix is a novel reinforcement. It yielded superior toughening and flexural performance compared to the particulate GICs used. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy.

    Science.gov (United States)

    Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

    2013-07-01

    The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

  9. Synthesis of porous inorganic hollow fibers without harmful solvents.

    Science.gov (United States)

    Shukla, Sushumna; de Wit, Patrick; Luiten-Olieman, Mieke W J; Kappert, Emiel J; Nijmeijer, Arian; Benes, Nieck E

    2015-01-01

    A route for the fabrication of porous inorganic hollow fibers with high surface-area-to-volume ratio that avoids harmful solvents is presented. The approach is based on bio-ionic gelation of an aqueous mixture of inorganic particles and sodium alginate during wet spinning. In a subsequent thermal treatment, the bio-organic material is removed and the inorganic particles are sintered. The method is applicable to the fabrication of various inorganic fibers, including metals and ceramics. The route completely avoids the use of organic solvents, such as N-methyl-2-pyrrolidone, and additives associated with the currently used fiber fabrication methods. In addition, it inherently avoids the manifestation of so-called macro voids and allows the facile incorporation of additional metal oxides in the inorganic hollow fibers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Highly permeable and mechanically robust silicon carbide hollow fiber membranes

    NARCIS (Netherlands)

    de Wit, Patrick; Kappert, Emiel; Lohaus, T.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

    2015-01-01

    Silicon carbide (SiC) membranes have shown large potential for applications in water treatment. Being able to make these membranes in a hollow fiber geometry allows for higher surface-to-volume ratios. In this study, we present a thermal treatment procedure that is tuned to produce porous silicon

  11. Synthesis of Porous Inorganic Hollow Fibers without Harmful Solvents

    NARCIS (Netherlands)

    Shukla, Sushumna; de Wit, Patrick; Luiten-Olieman, Maria W.J.; Kappert, Emiel; Nijmeijer, Arian; Benes, Nieck Edwin

    2015-01-01

    A route for the fabrication of porous inorganic hollow fibers with high surface-area-to-volume ratio that avoids harmful solvents is presented. The approach is based on bio-ionic gelation of an aqueous mixture of inorganic particles and sodium alginate during wet spinning. In a subsequent thermal

  12. Few photon switching with slow light in hollow fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Balic, Vlatko

    2009-01-01

    Cold atoms confined inside a hollow-core photonic-crystal fiber with core diameters of a few photon wavelengths are a promising medium for studying nonlinear optical interactions at extremely low light levels. The high electric field intensity per photon and interaction lengths not limited by dif...

  13. Spinning of hollow fiber ultrafiltration membranes from a polymer blend

    NARCIS (Netherlands)

    Wienk, I.M.; Wienk, I.M.; Olde scholtenhuis, F.H.A.; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.

    1995-01-01

    In this study the dry-wet spinning technique is used for the preparation of hollow fiber membranes. In the polymer solution a blend of two polymers, poly(ether sulfone) and poly(vinyl pyrrolidone), is used. The morphology of the membranes obtained is related to rheological characteristics and phase

  14. Hollow fiber apparatus and use thereof for fluids separations and heat and mass transfers

    Science.gov (United States)

    Bikson, Benjamin; Etter, Stephen; Ching, Nathaniel

    2014-06-10

    A hollow fiber device includes a hollow fiber bundle, comprising a plurality of hollow fibers, a first tubesheet and a second tubesheet encapsulating respective distal ends of the hollow fiber bundle. The tubesheets have boreholes in fluid communication with bores of the hollow fibers. In at least one of the tubesheets, the boreholes are formed radially. The hollow fiber device can be utilized in heat exchange, in gas/gas, liquid/liquid and gas/liquid heat transfer, in combined heat and mass transfer and in fluid separation assemblies and processes. The design disclosed herein is light weight and compact and is particularly advantageous when the pressure of a first fluid introduced into the bores of hollow fibers is higher than the pressure on the shell side of the device.

  15. Hollow fiber apparatus and use thereof for fluids separations and heat and mass transfers

    Science.gov (United States)

    Bikson, Benjamin; Etter, Stephen; Ching, Nathaniel

    2017-04-18

    A hollow fiber fluid separation device includes a hollow fiber cartridge, comprising a plurality of hollow fiber membranes arranged around a central tubular core, a first tubesheet and a second tubesheet encapsulating respective distal ends of the hollow fiber bundle. The tubesheets have boreholes in fluid communication with bores of the hollow fiber membrane. In at least one of the tubesheets, the boreholes are formed radially and are in communication with the central tubular core. The hollow fiber fluid separation device can be utilized in liquid separation applications such as ultrafiltration and in gas separation processes such as air separation. The design disclosed herein is light weight and compact and is particularly advantageous at high operating temperatures when the pressure of the feed fluid introduced into the bores of hollow fibers is higher than the pressure on the shell side of the device.

  16. Detritiation of water using microporous hollow-fiber membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, R.C. [Nevada Division of Environmental Protection, Carson City, NV (United States); Ahmed, T.; Middlebrooks, E.J. [Univ. of Nevada, Reno, NV (United States)

    1997-03-01

    A novel concept of tritium (HTO) removal with microporous hollow fiber membranes was evaluated in this study. Small-scale laboratory modules were constructed and tested to determine the mass transfer characteristics of the hollow fibers under varying system parameters. Tritiated water is pumped through the fiber lumen and air, saturated with water vapor, is pumped over the exterior of the fibers in a countercurrent mode. The high HTO concentration gradient encourages the HTO to diffuse across the porous membrane wall, and to transfer directly into the saturated air stream. A dimensionless mathematical correlation that predicts the tritium transfer coefficient across the membranes is presented for parallel flow modules. The measured overall mass transfer coefficients in the membrane module are two to three orders of magnitude greater than those of conventional bubble stripping. In additions, factors that influence the mass transfer performance of the membrane modules in practical applications are evaluated. The results indicate that very low concentrations of HTO can be separated from water using microporous hollow fiber membranes. 33 refs., 8 figs., 3 tabs.

  17. High-power picosecond pulse delivery through hollow core photonic band gap fibers

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Johansen, Mette Marie; Lyngsø, Jens Kristian

    2015-01-01

    We demonstrated robust and bend insensitive fiber delivery of high power pulsed laser with diffraction limited beam quality for two different kind of hollow core photonic band gap fibers......We demonstrated robust and bend insensitive fiber delivery of high power pulsed laser with diffraction limited beam quality for two different kind of hollow core photonic band gap fibers...

  18. Fluorescence-based remote irradiation sensor in liquid-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Zeltner, R.; Russell, P. St.J. [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Department of Physics, University of Erlangen-Nuremberg, Guenther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Bykov, D. S.; Xie, S. [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Euser, T. G. [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2016-06-06

    We report an irradiation sensor based on a fluorescent “flying particle” that is optically trapped and propelled inside the core of a water-filled hollow-core photonic crystal fiber. When the moving particle passes through an irradiated region, its emitted fluorescence is captured by guided modes of the fiber core and so can be monitored using a filtered photodiode placed at the fiber end. The particle speed and position can be precisely monitored using in-fiber Doppler velocimetry, allowing the irradiation profile to be measured to a spatial resolution of ∼10 μm. The spectral response can be readily adjusted by appropriate choice of particle material. Using dye-doped polystyrene particles, we demonstrate detection of green (532 nm) and ultraviolet (340 nm) light.

  19. Sensing Features of Long Period Gratings in Hollow Core Fibers

    Directory of Open Access Journals (Sweden)

    Agostino Iadicicco

    2015-04-01

    Full Text Available We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs fabricated in hollow core photonic crystal fibers (HC-PCFs by the pressure assisted Electric Arc Discharge (EAD technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperature, curvature, refractive index and pressure is presented. The achieved results show that LPGs in HC-PCFs represent a novel high performance sensing platform for measurements of different physical parameters including strain, temperature and, especially, for measurements of environmental pressure. The pressure sensitivity enhancement is about four times greater if we compare LPGs in HC and standard fibers. Moreover, differently from LPGs in standard fibers, these LPGs realized in innovative fibers, i.e., the HC-PCFs, are not sensitive to surrounding refractive index.

  20. Block copolymer/homopolymer dual-layer hollow fiber membranes

    KAUST Repository

    Hilke, Roland

    2014-12-01

    We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene and the selective layer with isopores was formed by micelle assembly of polystyrene-. b-poly-4-vinyl pyridine. The dual layers had an excellent interfacial adhesion and pore interconnectivity. The dual membranes showed pH response behavior like single layer block copolymer membranes with a low flux for pH values less than 3, a fast increase between pH4 and pH6 and a constant high flux level for pH values above 7. The dry/wet spinning process was optimized to produce dual layer hollow fiber membranes with polystyrene internal support layer and a shell block copolymer selective layer.

  1. Research on polyvinylidene fluoride (PVDF) hollow-fiber hemodialyzer.

    Science.gov (United States)

    Zhang, Qinglei; Lu, Xiaolong; Zhao, Lihua; Liu, Juanjuan; Wu, Chunfeng

    2016-06-01

    In this study, polyvinylidene fluoride (PVDF) hollow-fiber hemodialysis membranes were prepared by non-solvent-induced phase separation. The PVDF hollow-fiber hemodialyzers were prepared by centrifugal casting. The results showed that the PVDF membrane had better mechanical and separation properties when the membrane wall thickness was 40 μm and the N,N-dimethylacetamide in the core was 70 Vol%. Compared with commercial polysulfone hemodialysis membrane (Fresenius F60S membrane), the PVDF membrane had better mechanical property and ultrafiltration (UF) flux of pure water. The PVDF dialyzer's removal efficiency for middle molecules was proven to be much higher than that of the F60S dialyzer. The UF coefficient of a high-flux PVDF dialyzer is 62.6 ml/h/mm Hg, whereas F60S is 42.5 ml/h/mm Hg, which can promote clearance for middle molecules.

  2. Sandwich-structured hollow fiber membranes for osmotic power generation

    KAUST Repository

    Fu, Feng Jiang

    2015-11-01

    In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

  3. Adjustable Fiber Optic Microwave Transversal Filters

    Science.gov (United States)

    Shadaram, Mehdi; Lutes, George F.; Logan, Ronald T.; Maleki, Lutfollah

    1994-01-01

    Microwave transversal filters implemented as adjustable tapped fiber optic delay lines developed. Main advantages of these filters (in comparison with conventional microwave transversal filters) are small size, light weight, no need for matching of radio-frequency impedances, no need for shielding against electromagnetic radiation at suboptical frequencies, no need for mechanical tuning, high stability of amplitude and phase, and active control of transfer functions. Weights of taps in fiber optic delay lines adjusted.

  4. Influence of nano-fiber membranes on the silver ions released from hollow fibers containing silver particles

    Directory of Open Access Journals (Sweden)

    Li Huigai

    2016-01-01

    Full Text Available Polyether sulfone was dissolved into dimethylacetamide with the concentration of 20% to prepare a uniform solution for fabrication of nanofiber membranes by bubble electrospinning technique. Morphologies of the nanofiber film were carried out with a scanning electron microscope. The influence on the silver ions escaped from hollow fiber loaded with silver particles was exerted by using different release liquid. The water molecular clusters obtained from the nanofiber membranes filter can slow down the release of silver ions. However, the effect of slowing was weakened with the time increasing. In the end, the trend of change is gradually consistent with the trend of release of silver ions in the deionized water.

  5. Core–Shell Electrospun Hollow Aluminum Oxide Ceramic Fibers

    Directory of Open Access Journals (Sweden)

    Jonathan W. Rajala

    2015-10-01

    Full Text Available In this work, core–shell electrospinning was employed as a simple method for the fabrication of composite coaxial polymer fibers that became hollow ceramic tubes when calcined at high temperature. The shell polymer solution consisted of polyvinyl pyrollidone (PVP in ethanol mixed with an aluminum acetate solution to act as a ceramic precursor. The core polymer was recycled polystyrene to act as a sacrificial polymer that burned off during calcination. The resulting fibers were analyzed with X-ray diffraction (XRD and energy dispersive spectroscopy (EDS to confirm the presence of gamma-phase aluminum oxide when heated at temperatures above 700 °C. The fiber diameter decreased from 987 ± 19 nm to 382 ± 152 nm after the calcination process due to the polymer material being burned off. The wall thickness of these fibers is estimated to be 100 nm.

  6. Interference Cancellation for Hollow-Core Fiber Reference Cells

    DEFF Research Database (Denmark)

    Seppä, Jeremias; Merimaa, Mikko; Merimaa, Mikko

    2015-01-01

    Doppler-free saturated absorption spectroscopy of gases in hollow-core fiber (HCF)-based cells can be used for realizing new compact, robust, and portable frequency standards. In this paper, methods for cancelling interferences resulting from the optical connections between standard fiber and HCF...... and other factors such as varying coupling to HCF modes are investigated. Laser power modulation with simultaneous detection of ac and dc signal is used to separate saturated absorption from interferences. In addition, a technique of two piezoelectric stack actuators stretching the fiber at different...... locations is described. The presented experimental results demonstrate that 99% interference attenuation is readily attainable with the techniques. Frequency comb-referenced measurement of saturated acetylene absorption features near 1.54 μm, with fiber length and power modulation, is presented...

  7. Optical frequency standard using acetylene-filled hollow-core photonic crystal fibers

    DEFF Research Database (Denmark)

    Triches, Marco; Michieletto, Mattia; Hald, Jan

    2015-01-01

    Gas-filled hollow-core photonic crystal fibers are used to stabilize a fiber laser to the 13C2H2 P(16) (ν1+ν3) transition at 1542 nm using saturated absorption. Four hollow-core fibers with different crystal structure are compared in terms of long term lock-point repeatability and fractional freq...

  8. Hollow fiber membrane contactor as a gas-liquid model contactor

    NARCIS (Netherlands)

    Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

    2005-01-01

    Microporous hollow fiber gas-liquid membrane contactors have a fixed and well-defined gas-liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer

  9. Compact and Robust Refilling and Connectorization of Hollow Core Photonic Crystal Fiber Gas Reference Cells

    Science.gov (United States)

    Poberezhskiy, Ilya Y.; Meras, Patrick; Chang, Daniel H.; Spiers, Gary D.

    2007-01-01

    This slide presentation reviews a method for refilling and connectorization of hollow core photonic crystal fiber gas reference cells. Thees hollow-core photonic crystal fiber allow optical propagation in air or vacuum and are for use as gas reference cell is proposed and demonstrated. It relies on torch-sealing a quartz filling tube connected to a mechanical splice between regular and hollow-core fibers.

  10. Mode Division Multiplexing Exploring Hollow-Core Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Xu, Jing; Lyngso, Jens Kristian; Leick, Lasse

    2013-01-01

    We review our recent exploratory investigations on mode division multiplexing using hollow-core photonic bandgap fibers (HC-PBGFs). Compared with traditional multimode fibers, HC-PBGFs have several attractive features such as ultra-low nonlinearities, low-loss transmission window around 2 µm etc....... After having discussed the potential and challenges of using HC-PBGFs as transmission fibers for mode multiplexing applications, we will report a number of recent proof-of-concept results obtained in our group using direct detection receivers. The first one is the transmission of two 10.7 Gbit/s non......-return to zero (NRZ) data signals over a 30 m 7-cell HC-PBGF using the offset mode launching method. In another experiment, a short piece of 19-cell HC-PBGF was used to transmit two 20 Gbit/s NRZ channels using a spatial light modulator for precise mode excitation. Bit-error-ratio (BER) performances below...

  11. Hollow fiber membrane lumen modified by polyzwitterionic grafting

    KAUST Repository

    Le, Ngoc Lieu

    2016-08-24

    In this study, we demonstrate an effective way to modify the lumen of polyetherimide hollow fibers by grafting zwitterionic poly(sulfobetaine) to increase the membrane resistance to fouling. Surface-selective grafting of the protective hydrogel layers has been achieved in a facile two-step process. The first step is the adsorption of a macromolecular redox co-initiator on the lumen-side surface of the membrane, which in the second step, after flushing the lumen of the membrane with a solution comprising monomers and a complementary redox initiator, triggers the in situ cross-linking copolymerization at room temperature. The success of grafting reaction has been verified by the surface elemental analyses using X-ray photoelectron spectroscopy (XPS) and the surface charge evaluation using zeta potential measurements. The hydrophilicity of the grafted porous substrate is improved as indicated by the change of contact angle value from 44° to 30°, due to the hydration layer on the surface produced by the zwitterionic poly(sulfobetaine). Compared to the pristine polyetherimide (PEI) substrate, the poly(sulfobetaine) grafted substrates exhibit high fouling resistance against bovine serum albumin (BSA) adsorption, E. coli attachment and cell growth on the surface. Fouling minimization in the lumen is important for the use of hollow fibers in different processes. For instance, it is needed to preserve power density of pressure-retarded osmosis (PRO). In high-pressure PRO tests, a control membrane based on PEI with an external polyamide selective layer was seriously fouled by BSA, leading to a high water flux drop of 37%. In comparison, the analogous membrane, whose lumen was modified with poly(sulfobetaine), not only had a less water flux decline but also had better flux recovery, up to 87% after cleaning and hydraulic pressure impulsion. Clearly, grafting PRO hollow fiber membranes with zwitterionic polymeric hydrogels as a protective layer potentially sustains PRO

  12. Dual layer hollow fiber sorbents: Concept, fabrication and characterization

    KAUST Repository

    Bhandari, Dhaval

    2013-02-01

    Hollow fiber sorbents are pseudo-monolithic separations materials created with fiber spinning technology using a polymer \\'binder\\', impregnated with high loadings of sorbent \\'fillers\\' [1]. To increase purified gas recovery during the sorption step and to ensure consistent sorption capacity over repeated cycles, a dense, thin polymer barrier layer on the fiber sorbents is needed to allow only thermal interactions between the sorbate loaded layer and the thermal regeneration fluid. This paper considers materials and methods to create delamination-free dual layer fiber sorbents, with a porous core and a barrier sheath layer formed using a simultaneous co-extrusion process. Low permeability polymers were screened for sheath layer creation, with the core layer comprising cellulose acetate polymer as binder and zeolite NaY as sorbent fillers. Appropriate core and sheath layer dope compositions were determined by the cloud-point method and rheology measurements. The morphology of the as-spun fibers was characterized in detail by SEM, EDX and gas permeation analysis. A simplified qualitative model is described to explain the observed fiber morphology. The effects of core, sheath spin dope and bore fluid compositions, spinning process parameters such as air-gap height, spin dope and coagulation bath temperatures, and elongation draw ratio are examined in detail. © 2012 Elsevier B.V. All rights reserved.

  13. Biconical fibers as mode and wavelength filters.

    Science.gov (United States)

    Falciai, R; Scheggi, A M

    1989-04-01

    Mode and wavelength filtering characteristics of biconical fibers are examined. A model is considered which simulates the propagation conditions in a bicone made in a slightly overmoded fiber when illuminated at two different wavelengths. The possibility of wavelength selective coupling is evident in view of different applications.

  14. Hollow cathode lamp based Faraday anomalous dispersion optical filter.

    Science.gov (United States)

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-07-15

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the (88)Sr (5s(2))(1)S0 - (5s5p)(1)P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization.

  15. Sweep gas membrane distillation in a membrane contactor with metallic hollow fibers

    NARCIS (Netherlands)

    Shukla, Sushumna; Benes, Nieck Edwin; Vankelecom, I.F.J.; Mericq, J.P.; Belleville, M.P.; Hengl, N.; Sanchez Marcano, Jose

    2015-01-01

    This work revolves around the use of porous metal hollow fibers in membrane distillation. Various stages are covered, starting from membrane synthesis up to the testing of a pilot scale membrane module. Mechanically stable metal hollow fibers have been synthesized by phase inversion of a stainless

  16. Clarification of Orange Press Liquors by PVDF Hollow Fiber Membranes

    Directory of Open Access Journals (Sweden)

    Silvia Simone

    2016-01-01

    Full Text Available Press liquors are typical by-products of the citrus juice processing characterized by a high content of organic compounds and associated problems of environmental impact, which imply high treatment costs. However, these wastes contain a great number of health promoting substances, including fibers, carotenoids and phenolic compounds (mainly flavonoids, whose recovery against waste-destruction technologies is very attractive for new business opportunities. In this work, the clarification of orange press liquor by using microfiltration (MF membranes is studied as a preliminary step to obtain a permeate stream enriched in antioxidant compounds which can be further processed to produce extracts of nutraceutical and/or pharmaceutical interest. MF poly(vinylidene fluoride (PVDF hollow fibers were prepared by the dry/wet spinning technique. A series of fibers was produced from the same polymeric dope, in order to investigate the effect of selected spinning parameters, i.e., bore fluid composition and flowrate, on their properties. The morphology of the produced fibers was analyzed by Scanning Electron Microscopy (SEM. Fibers were further characterized for their mechanical properties, porosity, bubble point, pore size distribution and pure water permeability (PWP. Some of the produced fibers exhibited high permeability (pure water permeability ~530 L/m2·h·bar, coupled to good mechanical resistance and pore size in the range of MF membranes. These fibers were selected and used for the clarification of press liquor from orange peel processing. In optimized operating conditions, the selected fibers produced steady-state fluxes of about 41 L/m2·h with rejections towards polyphenols and total antioxidant activity of 4.1% and 1.4%, respectively.

  17. Measuring Beam Quality of Hollow Core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Shephard, J.D.; Roberts, John; Jones, J.D.C.

    2006-01-01

    In this paper, the authors measure the quality of the delivered beam from hollow core photonic crystal fibers (HC-PCFs). The$M^2$parameter is determined, and the near- to far-field transition is examined. The influence on these properties due to the presence of a core surround mode is evaluated.......17 for the same output beam. This highlights the need for careful consideration when measuring and describing the beam quality delivered by these novel photonic fibers........ The applicability of the International Standards Organization 11146 : 1999 standard for$M^2$measurement of the beam quality of HC-PCFs is discussed. Because they are dependent on the measurement parameters, such as choice of aperturing scheme and the axis of measurement,$M^2$values could vary from 1.32 to 3...

  18. Gaussian Filtering with Tapered Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Scolari, Lara; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2006-01-01

    We present a device based on a tapered Liquid Crystal Photonic Bandgap Fiber that allows active all-in-fiber filtering. The resulting Photonic Bandgap Fiber device provides a Gaussian filter covering the wavelength range 1200-1600 nm......We present a device based on a tapered Liquid Crystal Photonic Bandgap Fiber that allows active all-in-fiber filtering. The resulting Photonic Bandgap Fiber device provides a Gaussian filter covering the wavelength range 1200-1600 nm...

  19. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.

    2013-05-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  20. A simple way to establish a dual-core hollow fiber for laser surgery applications

    Science.gov (United States)

    Jing, Chengbin; Kendall, Wesley; Harrington, James A.

    2016-03-01

    A dual-core hollow fiber has two separate cores for propagation of light. Such a fiber can have some good applications in laser surgery. The dual-core guide can transmit an infrared laser beam for cutting or ablation while a visible laser beam is simultaneously transmitted as a pilot or aiming beam. The traditional fabrication procedure for a dual-core hollow fiber involves chemical vapor deposition (CVD) growth on silica tubing of an inner cladding layer followed by the deposition of a low index polymer on the outside of the tubing. This will provide a hollow structure that has a clad-core-clad tube. This work provides an alternative approach which involves nesting of two hollow waveguides to establish a dual-core hollow fiber. An Ag/AgI hollow glass fiber is fabricated for transmitting CO2 laser. Another silica glass tube is selected carefully so that its inner diameter is just slightly larger than the outer diameter of the Ag/AgI hollow fiber. The outer surface of the as-selected glass tubing is coated with a low refractive index polymer. The Ag/AgI hollow fiber was inserted into the polymer coated silica glass tubing to establish an air or silicone oil gap between the two tubes. A visible laser beam is transmitted through the outer tube's core. The CO2 laser beam is transmitted through the inner Ag/AgI hollow fiber. The dual-core hollow fibers show good transmission for both the red aiming beam and the CO2 laser. Therefore this structure can be a good candidate for laser surgery applications.

  1. Human hepatocyte functions in a crossed hollow fiber membrane bioreactor.

    Science.gov (United States)

    De Bartolo, Loredana; Salerno, Simona; Curcio, Efrem; Piscioneri, Antonella; Rende, Maria; Morelli, Sabrina; Tasselli, Franco; Bader, Augustinus; Drioli, Enrico

    2009-05-01

    An important challenge in liver tissue engineering is the development of bioartificial systems that are able to favour the liver reconstruction and to modulate liver cell behaviour. A crossed hollow fiber membrane bioreactor was developed to support the long-term maintenance and differentiation of human hepatocytes. The bioreactor consists of two types of hollow fiber (HF) membranes with different molecular weight cut-off (MWCO) and physico-chemical properties cross-assembled in alternating manner: modified polyetheretherketone (PEEK-WC) and polyethersulfone (PES), used for the medium inflow and outflow, respectively. The combination of these two fiber set produces an extracapillary network for the adhesion of cells and a high mass exchange through the cross-flow of culture medium. The transport of liver specific products such as albumin and urea together with the transport of drug such as diazepam was modelled and compared with the experimental metabolic data. The theoretical metabolite concentration differed 7.5% for albumin and 5% for urea with respect to experimental data. The optimised perfusion conditions of the bioreactor allowed the maintenance of liver functions in terms of urea synthesis, albumin secretion and diazepam biotransformation up to 18 days of culture. In particular the good performance of the bioreactor was confirmed by the high rate of urea synthesis (28.7 microg/h 10(6) cells) and diazepam biotransformation. In the bioreactor human hepatocytes expressed at high levels the individual cytochrome P450 isoenzymes involved in the diazepam metabolism. The results demonstrated that crossed HF membrane bioreactor is able to support the maintenance of primary human hepatocytes preserving their liver specific functions for all investigated period. This device may be a potential tool in the liver tissue engineering for drug metabolism/toxicity testing and study of disease pathogenesis alternatively to animal experimentation.

  2. Hollow fiber membrane contactor as a gas-liquid model contactor

    OpenAIRE

    Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

    2005-01-01

    Microporous hollow fiber gas-liquid membrane contactors have a fixed and well-defined gas-liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer coefficient from first principles. Moreover, in the case of gas-liquid membrane contactor, the gas-liquid exposure time can be varied easily and independently without disturbing the gas-liquid interfa...

  3. Measurement of blood glucose by infrared spectroscopy using hollow-optical fiber probe

    Science.gov (United States)

    Tanaka, Y.; Kino, S.; Matsuura, Y.

    2013-03-01

    An infrared spectroscopy system based on a hollow-optical fiber probe for measurement of blood glucose concentration is developed. The probe consists of a flexible hollow-optical fiber and an ATR prism attached at the distal end of the fiber. This flexible probe enables measurement of oral mucosa and ear lobes that have blood capillaries near the skin surface. Experimental results show that absorption peaks of blood glucose are detected by the system.

  4. Micro-Displacement Sensor Based on a Hollow-Core Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Orlando Frazão

    2012-12-01

    Full Text Available A sensing head based on a hollow-core photonic crystal fiber for in-reflection measurement of micro-displacements is presented. The sensing structure takes advantage of the multimodal behavior of a short segment of hollow-core photonic crystal fiber in-reflection, being spliced to a single mode fiber at its other end. A modal interferometer is obtained when the sensing head is close to a mirror, through which displacement is measured.

  5. Optical phase response to temperature in a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Meiselman, Seth; Cranch, Geoffrey A

    2017-10-30

    Analysis of previous measurements of thermal phase sensitivity in hollow core photonic crystal fibers is presented with additional new corroborating measurements, resolving a discrepancy in previously reported results. We extend an existing derivation of thermo-mechanical phase sensitivity in solid- and hollow-core photonic crystal fiber to also include kagome lattice photonic crystal fibers. Measured thermal phase response is shown to agree with theoretical prediction to within a few percent.

  6. Performance of different hollow fiber membranes for seawater desalination using membrane distillation

    KAUST Repository

    Francis, Lijo

    2014-08-11

    Membrane distillation requires a highly porous hydrophobic membrane with low surface energy. In this paper, we compare the direct contact membrane distillation (DCMD) performances of four different types of in-house fabricated hollow fiber membranes and two different commercially available hollow fiber membranes. Hollow fiber membranes are fabricated using wet-jet phase inversion technique and the polymeric matrices used for the fabrication are polyvinylidine fluoride (PVDF) and polyvinyl chloride (PVC). Commercial hollow fiber membrane materials are made of polytetrafluoroethylene (PTFE) and polypropylene (PP). PVDF hollow fibers showed a superior performance among all the hollow fibers tested in the DCMD process and gave a water vapor flux of 31 kg m-2h-1 at a feed and coolant inlet temperatures of 80 and 20°C, respectively. Under the same conditions, the water vapor flux observed for PP, PTFE, and PVC hollow fiber membranes are 13, 11, and 6 kg m-2h-1, respectively, with 99.99% salt rejection observed for all membranes used.

  7. Formation and characterization of magnetic barium ferrite hollow fibers with low coercivity via co-electrospun

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gui-fang, E-mail: guifang777@163.com; Zhang, Zi-dong, E-mail: 1986zzd@163.com; Dang, Feng, E-mail: dangfeng@sdu.edu.cn; Cheng, Chuan-bing, E-mail: 807033063@qq.com; Hou, Chuan-xin, E-mail: 710313782@qq.com; Liu, Si-da, E-mail: superliustar@hotmail.com

    2016-08-15

    BaFe{sub 12}O{sub 19} fibers and hollow fibers were successfully prepared by electrospun and co-electrospun. A very interesting result appeared in this study that hollow fibers made by co-electrospun showed low coercivity values of a few hundred oersteds, compared with the coercivity values of more than thousand oersteds for the fibers made by electrospun. So the hollow fibers with high saturation magnetization (M{sub s}) and while comparatively low coercivity (H{sub c}) exhibited strong magnetism and basically showed soft character. And this character for hollow fibers will lead to increase of the permeability for the samples which is favorable for impedance matching in microwave absorption. So these hollow fibers are promised to have use in a number of applications, such as switching and sensing applications, electromagnetic materials, microwave absorber. - Highlights: • BaFe{sub 12}O{sub 19} fibers were prepared via electrospinning successfully. • The coercivity has a value of a few hundred oersteds for the hollow fibers made by coaxial electrospun. • BaFe{sub 12}O{sub 19} with high saturation magnetization and low coercivity shows great potential in microwave absorbing application.

  8. Feasibility of hollow core fiber based optical lattice clock

    Science.gov (United States)

    Ilinova, Ekaterina; Babb, James F.; Derevianko, Andrei; Theoretical atomic; molecular physics group Team; Atomic; Molecular Physics Division Team

    2017-04-01

    The possibility of building the optical lattice clock based on the narrow 1S0 -3P0 transition in Hg and other alkaline-earth like atoms optically trapped inside the hollow core fiber has been studied. The general form of the long range atom-surface interaction potential at non-zero temperatures has been calculated for the hollow capillary geometry. The resulting 1S0 -3P0 transition frequency shift has been calculated for Sr and Hg atoms as a function of their position inside the capillary. Its dependence on the geometric parameters and optical properties of the capillary material has been analyzed. The resonant enhancement of the atom-surface interaction potential and radiative decay rate of the 3P0 state at certain parameters of the waveguide has been studied. For the silica capillary with inner radius Rin > 15 μm and thickness d 1 μm the atom surface interaction induced 1S0 -3P0 transition frequency shift on the capillary axis can be suppressed down to the level δν / ν <10-18 . The additional frequency shifts and atom loss from the optical trap due to the residual birefringence of the waveguide and collisions with the buffer gas molecules have been evaluated. University of Nevada, Reno.

  9. Ethylene glycol as bore fluid for hollow fiber membrane preparation

    KAUST Repository

    Le, Ngoc Lieu

    2017-03-31

    We proposed the use of ethylene glycol and its mixture with water as bore fluid for the preparation of poly(ether imide) (PEI) hollow fiber membranes and compared their performance and morphology with membranes obtained with conventional coagulants (water and its mixture with the solvent N-methylpyrrolidone (NMP)). Thermodynamics and kinetics of the systems were investigated. Water and 1:1 water:EG mixtures lead to fast precipitation rates. Slow precipitation is observed for both pure EG and 9:1 NMP:water mixture, but the reasons for that are different. While low osmotic driving force leads to slow NMP and water transport when NMP:water is used, the high EG viscosity is the reason for the slow phase separation when EG is the bore fluid. The NMP:water mixture produces fibers with mixed sponge-like and finger-like structure with large pores in the inner and outer layers; and hence leading to a high water permeance and a high MWCO suitable for separation of large-sized proteins. As compared to NMP:water, using EG as bore fluid provides fibers with a finger-like bilayered structure and sponge-like layers near the surfaces, and hence contributing to the higher water permeance. It also induces small pores for better protein rejection.

  10. Studies on poly (vinyl chloride/silica dioxide composite hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Mei Shuo

    2016-01-01

    Full Text Available Poly (vinyl chloride/silica dioxide composite hollow fiber membranes were prepared by using the method of immersion-precipitation process. The influences of stretching ratio on the formation of the interfacial microporous of poly (vinyl chloride/silica dioxide composite hollow fiber membranes were specifically investigated by scanning electron microscope, dynamic mechanical analysis, and finite element method. Results show that with the stretching ratio increasing, numerous IFM appear on the surface of membranes. Finite element method actually reflects the dynamic change of microporous structure of poly (vinyl chloride/silica dioxide composite hollow fiber membranes.

  11. Screening and quantification of anticancer compounds in traditional Chinese medicine by hollow fiber cell fishing and hollow fiber liquid/solid-phase microextraction.

    Science.gov (United States)

    Wang, Caiyun; Hu, Shuang; Chen, Xuan; Bai, Xiaohong

    2016-05-01

    Hollow fiber cell fishing, based on HepG-2, SKOV-3, and ACHN cancer cells, and hollow fiber liquid/solid microextraction with HPLC were developed and introduced for researching the anticancer activity of Rhizoma Curcumae Longae, Radix Curcumae, and Rhizoma Curcumae. The structures of curcumin, demethoxycurcumin, and bisdemethoxycurcumin screened were identified and their contents were determined. The compound target fishing factors and cell apoptosis rates under the effect of the three medicines were determined. The binding sites (cell membrane and cell organelle) and binding target (phospholipase C) on the cell were researched. Hollow fiber liquid/solid-phase microextraction mechanism was analyzed and expounded. Before the application, cell seeding time, growth state and survival rate, compound nonspecific binding, positive and negative controls, repeatability in hollow fiber cell fishing with high-performance liquid chromatography; extraction solvent, sample pH, salt concentration, agitation speed, extraction time, temperature and sample volume in hollow fiber liquid/solid-phase microextraction with high-performance liquid chromatography were investigated. The results demonstrated that the proposed strategy is a simple and quick method to identify bioactive compounds at the cellular level as well as determine their contents (particularly trace levels of the bioactive compounds), analyze multicompound and multitarget entirety effects, and elucidate the efficacious material base in traditional medicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fabrication of micro-hollow fiber by electrospinning process in near-critical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Koichi; Wahyudiono,; Kanda, Hideki; Goto, Motonobu, E-mail: mgoto@nuce.nagoya-u.ac.jp [Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Machmudah, Siti [Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan and Department of Chemical Engineering, Sepuluh Nopember Institute of Technology, Kampus ITS Sukolilo, Surabaya 60111 (Indonesia); Okubayashi, Satoko [Department of Advanced Fibro-Science, Kyoto Institute of Technology, Kyoto 606-8585, Japan (Japan); Fukuzato, Ryuichi [SCF Techno-Link, Inc., Ashiya 659-0033 (Japan)

    2014-02-24

    Electrospinning is a simple technique that has gained much attention because of its capability and feasibility in the fabrication of large quantities of fibers from polymer with diameters ranging in nano-microscale. These fibers provided high surface area to volume ratios, and it was of considerable interest for many applications, such as nanoparticle carriers in controlled release, scaffolds in tissue engineering, wound dressings, military wear with chemical and biological toxin-resistance, nanofibrous membranes or filters, and electronic sensors. Recently there has been a great deal of progress in the potential applications of hollow fibers in microfluids, photonics, and energy storage. In this work, electrospinning was conducted under high-pressure carbon dioxide (CO{sub 2}) to reduce the viscosity of polymer solution. The experiments were conducted at 313 K and ∼8.0 MPa. Polymer solution containing 5 wt% polymers which prepared in dichloromethane (DCM) with polyvinylpyrrolidone (PVP) to poly-L-lactic acid (PLLA) ratio 80:20 was used as a feed solution. The applied voltage was 15 kV and the distance of nozzle and collector was 8 cm. The morphology and structure of the fibers produced were observed using scanning electron microscopy (SEM). Under pressurized CO{sub 2}, PVP electrospun was produced without bead formation with diameter ranges of 608.50 - 7943.19 nm. These behaviors hold the potential to considerably improve devolatilization electrospinning processes.

  13. Dynamic fiber delivery of 3 W 160 fs pulses with photonic crystal hollow core fiber patchcord.

    Science.gov (United States)

    Resan, Bojan; Auchli, Raffael; Villamaina, Vesna; Holtz, Ronald

    2017-10-02

    We report output characteristics of a connectorized hollow core photonics crystal fiber when it is subjected to coiling down to a 50 mm radius, bending, and torsion. We achieved coupling efficiency up to 73% with an output average power of 2 W and 24 nJ pulse energy. With optimized coupling, depolarization was as low as 7%. Coiling and bending of the photonic crystal patchcord introduces little distortion; torsion, however, changes the polarization drastically. To our knowledge, this is the first report on dynamic fiber delivery of fs pulses.

  14. Economic comparison of transverse and longitudinal flow hollow fiber membrane modules for reverse osmosis and ultrafiltration

    NARCIS (Netherlands)

    Futselaar, H.; Zoontjes, R.J.C.; Reith, T.; Racz, I.G.

    1993-01-01

    The presently used hollow fiber membrane modules consist of a bundle of fibers in a cylindrical polymer or metal shell parallel to the shell axis. The feed solution flows either through the lumen or at the outside parallel to the fibers. This paper compares the performance of these modules with a

  15. Low Loss and Highly Birefringent Hollow-Core Photonic Crystal Fiber

    DEFF Research Database (Denmark)

    Roberts, P. John; Williams, D.P.; Mangan, Brian J.

    2006-01-01

    A hollow-core photonic crystal fiber design is proposed which enables both low-loss and polarization-maintained signal propagation. The design relies on an arrangement of antiresonant features positioned on the glass ring that surrounds the air core.......A hollow-core photonic crystal fiber design is proposed which enables both low-loss and polarization-maintained signal propagation. The design relies on an arrangement of antiresonant features positioned on the glass ring that surrounds the air core....

  16. Testing and performance analysis of a hollow fiber-based core for evaporative cooling and liquid desiccant dehumidification

    DEFF Research Database (Denmark)

    Jradi, Muhyiddine; Riffat, Saffa

    2016-01-01

    In this study, an innovative heat and mass transfer core is proposed to provide thermal comfort and humidity control using a hollow fiber contactor with multiple bundles of micro-porous hollow fibers. The hollow fiberbased core utilizes 12 bundles aligned vertically, each with 1,000 packed polypr...... of 47%. Being cheap and simple to design with their attractive heat and mass transfer characteristics and the corresponding large surface area-to-volume ratio, hollow fiber membrane contactors provide a promising alternative for cooling and dehumidification applications.......In this study, an innovative heat and mass transfer core is proposed to provide thermal comfort and humidity control using a hollow fiber contactor with multiple bundles of micro-porous hollow fibers. The hollow fiberbased core utilizes 12 bundles aligned vertically, each with 1,000 packed...

  17. Ultrafast Mid-IR Nonlinear Optics in Gas-filled Hollow-core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Habib, Selim

    action of self-focusing self-phase modulation (SPM) and anomalous GVD allows strong soliton self-compression down to sub-single cycle duration inside HC-AR fiber. The peak intensity at the maximum temporal compression can reach over 1014 W/cm2 which is sufficient to ionize the gas and form a plasma. We......Invention of hollow-core fiber has been proven an ideal medium to study light-gas interaction. Tight confinement of light inside hollowcore fiber allows unremitting and tailored interaction between light and gas over long distances. In this work, we used a special kind of hollowcore fiberhollow...

  18. Integrated carbon fiber electrodes within hollow polymer microneedles for transdermal electrochemical sensing.

    Science.gov (United States)

    Miller, Philip R; Gittard, Shaun D; Edwards, Thayne L; Lopez, Deanna M; Xiao, Xiaoyin; Wheeler, David R; Monteiro-Riviere, Nancy A; Brozik, Susan M; Polsky, Ronen; Narayan, Roger J

    2011-03-30

    In this study, carbon fiber electrodes were incorporated within a hollow microneedle array, which was fabricated using a digital micromirror device-based stereolithography instrument. Cell proliferation on the acrylate-based polymer used in microneedle fabrication was examined with human dermal fibroblasts and neonatal human epidermal keratinocytes. Studies involving full-thickness cadaveric porcine skin and trypan blue dye demonstrated that the hollow microneedles remained intact after puncturing the outermost layer of cadaveric porcine skin. The carbon fibers underwent chemical modification in order to enable detection of hydrogen peroxide and ascorbic acid; electrochemical measurements were demonstrated using integrated electrode-hollow microneedle devices.

  19. Direct fiber comb stabilization to a gas-filled hollow-core photonic crystal fiber.

    Science.gov (United States)

    Wu, Shun; Wang, Chenchen; Fourcade-Dutin, Coralie; Washburn, Brian R; Benabid, Fetah; Corwin, Kristan L

    2014-09-22

    We have isolated a single tooth from a fiber laser-based optical frequency comb for nonlinear spectroscopy and thereby directly referenced the comb. An 89 MHz erbium fiber laser frequency comb is directly stabilized to the P(23) (1539.43 nm) overtone transition of (12)C(2)H(2) inside a hollow-core photonic crystal fiber. To do this, a single comb tooth is isolated and amplified from 20 nW to 40 mW with sufficient fidelity to perform saturated absorption spectroscopy. The fractional stability of the comb, ~7 nm away from the stabilized tooth, is shown to be 6 × 10(-12) at 100 ms gate time, which is over an order of magnitude better than that of a comb referenced to a GPS-disciplined Rb oscillator.

  20. High Power Spark Delivery System Using Hollow Core Kagome Lattice Fibers

    Directory of Open Access Journals (Sweden)

    Ciprian Dumitrache

    2014-08-01

    Full Text Available This study examines the use of the recently developed hollow core kagome lattice fibers for delivery of high power laser pulses. Compared to other photonic crystal fibers (PCFs, the hollow core kagome fibers have larger core diameter (~50 µm, which allows for higher energy coupling in the fiber while also maintaining high beam quality at the output (M2 = 1.25. We have conducted a study of the maximum deliverable energy versus laser pulse duration using a Nd:YAG laser at 1064 nm. Pulse energies as high as 30 mJ were transmitted for 30 ns pulse durations. This represents, to our knowledge; the highest laser pulse energy delivered using PCFs. Two fiber damage mechanisms were identified as damage at the fiber input and damage within the bulk of the fiber. Finally, we have demonstrated fiber delivered laser ignition on a single-cylinder gasoline direct injection engine.

  1. Block copolymer hollow fiber membranes with catalytic activity and pH-response

    KAUST Repository

    Hilke, Roland

    2013-08-14

    We fabricated block copolymer hollow fiber membranes with self-assembled, shell-side, uniform pore structures. The fibers in these membranes combined pores able to respond to pH and acting as chemical gates that opened above pH 4, and catalytic activity, achieved by the incorporation of gold nanoparticles. We used a dry/wet spinning process to produce the asymmetric hollow fibers and determined the conditions under which the hollow fibers were optimized to create the desired pore morphology and the necessary mechanical stability. To induce ordered micelle assembly in the doped solution, we identified an ideal solvent mixture as confirmed by small-angle X-ray scattering. We then reduced p-nitrophenol with a gold-loaded fiber to confirm the catalytic performance of the membranes. © 2013 American Chemical Society.

  2. Highly scalable ZIF-based mixed-matrix hollow fiber membranes for advanced hydrocarbon separations

    KAUST Repository

    Zhang, Chen

    2014-05-29

    ZIF-8/6FDA-DAM, a proven mixed-matrix material that demonstrated remarkably enhanced C3H6/C3H8 selectivity in dense film geometry, was extended to scalable hollow fiber geometry in the current work. We successfully formed dual-layer ZIF-8/6FDA-DAM mixed-matrix hollow fiber membranes with ZIF-8 nanoparticle loading up to 30 wt % using the conventional dry-jet/wet-quench fiber spinning technique. The mixed-matrix hollow fibers showed significantly enhanced C3H6/C3H8 selectivity that was consistent with mixed-matrix dense films. Critical variables controlling successful formation of mixed-matrix hollow fiber membranes with desirable morphology and attractive transport properties were discussed. Furthermore, the effects of coating materials on selectivity recovery of partially defective fibers were investigated. To our best knowledge, this is the first article reporting successful formation of high-loading mixed-matrix hollow fiber membranes with significantly enhanced selectivity for separation of condensable olefin/paraffin mixtures. Therefore, it represents a major step in the research area of advanced mixed-matrix membranes. © 2014 American Institute of Chemical Engineers.

  3. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    Directory of Open Access Journals (Sweden)

    Baiwang Zhao

    2015-11-01

    Full Text Available In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process.

  4. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System.

    Science.gov (United States)

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-11-16

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18-22 g/m³ to a range of 13.5-18.3 g/m³. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process.

  5. Vacuum membrane distillation of liquid desiccants Utilizing Hollow Fiber Membranes

    KAUST Repository

    Lefers, Ryan

    2018-01-31

    This paper documents the testing of a vacuum membrane distillation system intended for use with liquid desiccants. Liquid desiccants offer the possibility for low-energy, ambient temperature dehumidification. Effective desalination and purification of diluted desiccants outputs two important products: a concentrated desiccant for reuse in dehumidification and fresh water. In this study, vacuum membrane distillation was used in the laboratory to purify diluted liquid desiccants. Calcium chloride and magnesium chloride were the desiccants selected for testing. Desiccant solutions were pumped through the lumens of poly(vinylidene fluoride) (PVDF) hollow fiber membranes at varying feed inlet temperatures, solution velocity rates and vacuum set points during membrane distillation. An average flux of 8 kg m-2 h-1 was obtained using 30 wt% magnesium chloride solution at a temperature of 50 °C while applying vacuum to achieve 25 mbar absolute pressure on the air side of the membrane. The results are promising for the development of a full-scale vacuum membrane distillation process for desiccant solution regeneration and fresh water recovery. In addition, the recovered condensate was of sufficient quality for use in agricultural irrigation or drinking water.

  6. Preparation of anticoagulant polyvinylidene fluoride hollow fiber hemodialysis membranes.

    Science.gov (United States)

    Zhang, Qinglei; Lu, Xiaolong; Yang, Shichun; Zhang, Qingzhao; Zhao, Lihua

    2017-02-01

    In this study, polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) were modified by coating with polyvinyl alcohol (PVA) and chitosan. The influences of PVA and chitosan amount on PVDF membrane mechanical and separation performance were investigated. The results showed that the modified PVDF membranes had better mechanical and separation performance when the amount of PVA and chitosan was 20 mg/m2. At the same time, the biocompatibility of PVDF membranes was also investigated. Compared with virgin PVDF membranes, the modified PVDF membranes showed better anticoagulation, hydrophilicity, less bovine serum albumin (BSA) adsorption, and lower hemolytic ratio. The anticoagulation behavior of modified PVDF membranes coating with PVA had been obviously improved. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the modified PVDF membrane are 44.8 s and 72.5 s while the PT and APTT of virgin PVDF membrane are 15.6 s and 37.3 s. The advancing water contact angle (WCA) and BSA adsorption of the modified PVDF membrane coating with PVA are 24° and 23 mg/m2 while virgin PVDF membrane is 52° and 49 mg/m2. However, further biocompatibility evaluation is needed to obtain a more comprehensive conclusion.

  7. All-fiber wavelength filter from successive biconical tapers.

    Science.gov (United States)

    Lacroix, S; Gonthier, F; Bures, J

    1986-10-01

    We demonstrate the cascading of biconical fiber tapers as a simple method for converting monomode optical fibers into wavelength filters with a prescribed response. As an example, we made a narrow-bandpass filter consisting of four biconical tapers of different elongations made in succession on a single fiber. The transmission peak of the spectral response of the filter is centered on an arbitrary wavelength within the monomode domain of the fiber. The half-power width is approximately 6 nm.

  8. High-power picosecond pulse delivery through hollow core photonic band gap fibers

    DEFF Research Database (Denmark)

    Michieletto, Mattia; Johansen, Mette Marie; Lyngsø, Jens Kristian

    2016-01-01

    We demonstrated robust and bend insensitive fiber delivery of high power laser with diffraction limited beam quality for two different kinds of hollow core band gap fibers. The light source for this experiment consists of ytterbium-doped double clad fiber aeroGAIN-ROD-PM85 in a high power amplifier...... setup. It provided 22ps pulses with a maximum average power of 95W, 40MHz repetition rate at 1032nm (~2.4μJ pulse energy), with M2 power output for a 5 meters fiber. The damage...... threshold for a 19-cell hollow core photonic bandgap fiber exceeded the maximum power provided by the light source and up to 76W average output power was demonstrated for a 1m fiber. In both cases, no special attention was needed to mitigate bend sensitivity. The fibers were coiled on 8 centimeters radius...

  9. Multiple soliton compression stages in mid-IR gas-filled hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Md Selim; Markos, Christos; Bang, Ole

    2017-01-01

    The light confinement inside hollow-core (HC) fibers filled with noble gases constitutes an efficient route to study interesting soliton-plasma dynamics [1]. More recently, plasma-induced soliton splitting at the self-compression point was observed in a gas-filled fiber in the near-IR [2]. However...

  10. The effect of the production method on the mechanical strength of an alumina porous hollow fiber

    NARCIS (Netherlands)

    de Wit, Patrick; van Daalen, Frederique S.; Benes, Nieck E.

    2017-01-01

    The mechanical strength of inorganic porous hollow fibers is an important property and is strongly affected by the production method. Three production methods for fibers are compared: non-solvent induced phase separation (NIPS), bio-ionic gelation with an internal multivalent ion source (BIG-I), and

  11. Efficient optimization of hollow-core photonic crystal fiber design using the finite-element method

    DEFF Research Database (Denmark)

    Holzlöhner, Ronald; Burger, Sven; Roberts, John

    2006-01-01

    We employ a finite-element (FE) solver with adaptive grid refinement to model hollow-core photonic crystal fibers (HC-PCFs) whose core is formed from 19 omitted cladding unit cells. We optimize the complete fiber geometry for minimal field intensity at material/air interfaces, which indicates low...

  12. Porous stainless steel hollow fiber membranes via dry-wet spinning

    NARCIS (Netherlands)

    Luiten-Olieman, Maria W.J.; Winnubst, Aloysius J.A.; Nijmeijer, Arian; Wessling, Matthias; Benes, Nieck Edwin

    2011-01-01

    Porous stainless steel hollow fibers have been prepared via the dry–wet spinning process, based on phase inversion of a particle loaded polymer solution, followed by sintering. The morphology of the green fibers combines sponge like structures and macro voids, and is related to the dynamics of the

  13. Orbital angular momentum modes by twisting of a hollow core antiresonant fiber

    DEFF Research Database (Denmark)

    Stefani, Alessio; Kuhlmey, Boris T.; Fleming, Simon

    2017-01-01

    physical phenomena [2]. We previously reported the ability to create helical hollow fibers by mechanically twisting a tube lattice fiber made of polyurethane, the twist of which can be adjusted and reversed [3]. In this work we report how such deformation induces a mode transformation to an OAM mode...

  14. Nonlinear optics at the single-photon level inside a hollow core fiber

    DEFF Research Database (Denmark)

    Hofferberth, Sebastian; Peyronel, Thibault; Liang, Qiyu

    2011-01-01

    Cold atoms inside a hollow core fiber provide an unique system for studying optical nonlinearities at the few-photon level. Confinement of both atoms and photons inside the fiber core to a diameter of just a few wavelengths results in high electric field intensity per photon and large optical dep...

  15. Generation of hollow beam with radially polarized vortex beam and complex amplitude filter.

    Science.gov (United States)

    Lin, Jie; Chen, Ran; Yu, Haichao; Jin, Peng; Ma, Yuan; Cada, Michael

    2014-07-01

    The generation of hollow beams with a long focal depth from a radially polarized Bessel-Gaussian beam with a second-order vortex phase and an amplitude filter is theoretically investigated by Richards-Wolf's integral. The null intensity on the optical axis is achieved by introducing the second-order vortex. The long focal depth is a result of the amplitude filtering based on the cosine function and Euler transformation. Numerical results indicate that the focal depth of a hollow beam is improved from 0.96λ to 2.28λ with a slight increase of the transverse size for the simplest amplitude filter design. The intensity distribution twist phenomenon of the x- and y-polarized components around the optical axis due to the introducing of the vortex phase is also discussed. It is believed that the proposed scheme can be used to achieve particle acceleration and optical trapping.

  16. Hollow fiber structures, methods of use thereof, methods of making, and pressure-retarded processes

    KAUST Repository

    Le, Lieu Ngoc

    2016-12-08

    Embodiments of the present disclosure provide for composite materials, methods of making composite materials, methods of using composite materials, and the like. In particular, the present application relates to hollow fibers and to pressure-retarded osmosis systems comprising said fibers. The hollow fibers have an inside layer and an outside layer, wherein the outside layer covers an outside surface of the inside layer, wherein the inside layer forms a boundary around the lumen, wherein the inside layer includes a bi-layer structure, wherein the bi-layer structure includes a sponge-like layer and a finger-like layer, wherein the sponge-like layer is disposed closer to the lumen of the hollow fiber and the finger-like layer is disposed on the sponge-like layer on the side opposite the lumen, wherein the outside layer includes a polyamide layer.

  17. Macroscopic Graphene Fibers Directly Assembled from CVD-Grown Fiber-Shaped Hollow Graphene Tubes.

    Science.gov (United States)

    Chen, Tao; Dai, Liming

    2015-12-01

    Using a copper wire as the substrate for the CVD growth of a hollow multilayer graphene tube, we prepared a macroscopic porous graphene fiber by removing the copper in an aqueous mixture solution of iron chloride (FeCl3, 1 M) and hydrochloric acid (HCl, 3 M) and continuously drawing the newly released graphene tube out of the liquid. The length of the macroscopic graphene fiber thus produced is determined mainly by the length of the copper wire used. The resultant macroscopic graphene fiber with the integrated graphene structure exhibited a high electrical conductivity (127.3 S cm(-1)) and good flexibility over thousands bending cycles, showing great promise as flexible electrodes for wearable optoelectronics and energy devices-exemplified by its use as a flexible conductive wire for lighting a LED and a cathode in a fiber-shaped dye-sensitized solar cell (DSSC) with one of the highest energy conversion efficiencies (3.25%) among fiber-shaped DSSCs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Energy loss in gas lasers operating in hollow-core optical fibers

    Science.gov (United States)

    Lane, Ryan A.; Madden, Timothy J.

    2017-03-01

    The output of solid core fiber lasers is constrained in the mid-infrared due to the absorption properties of silica. Optically pumped gas lasers can reach the mid-infrared but require long path lengths for interaction between the pump light and gain medium. Optically pumped gas lasers where the gain medium is contained in a hollow-core optical fiber may provide a robust and compact platform that combines advantages of fiber and optically-pumped gas lasers. Experimental demonstrations of gas-filled-fiber lasers have been reported. The energy output of a molecular gas laser operating in a hollow-core optical fiber is computationally modeled using rate equations. The rate equations include terms for various physical processes including molecular self-collisions, molecular collisions with the fiber walls, and fiber attenuation. The rate equations are solved for a time-dependent, one-dimensional fiber model with an acetylene gain medium that lases along rotation-vibrational transitions. The energy output and losses are computed for multiple configurations. Model correspondence with reported experiments is shown. The computed energy losses due to backwards propagating light, fiber losses, and molecular collisions are applied to pulsed, continuous wave, and synchronously pumped gas lasers operating in hollow-core optical fibers. Energy losses due to molecular collisions are used to estimate heating in the gain medium.

  19. Integrated carbon fiber electrodes within hollow polymer microneedles for transdermal electrochemical sensing

    OpenAIRE

    Miller, Philip R; Gittard, Shaun D.; Edwards, Thayne L.; Lopez, DeAnna M.; Xiao, Xiaoyin; Wheeler,David R.; Monteiro-Riviere, Nancy A.; Brozik, Susan M.; Polsky, Ronen; Narayan, Roger J

    2011-01-01

    In this study, carbon fiber electrodes were incorporated within a hollow microneedle array, which was fabricated using a digital micromirror device-based stereolithography instrument. Cell proliferation on the acrylate-based polymer used in microneedle fabrication was examined with human dermal fibroblasts and neonatal human epidermal keratinocytes. Studies involving full-thickness cadaveric porcine skin and trypan blue dye demonstrated that the hollow microneedles remained intact after punct...

  20. Matrimid® derived carbon molecular sieve hollow fiber membranes for ethylene/ethane separation

    KAUST Repository

    Xu, Liren

    2011-09-01

    Carbon molecular sieve (CMS) membranes have shown promising separation performance compared to conventional polymeric membranes. Translating the very attractive separation properties from dense films to hollow fibers is important for applying CMS materials in realistic gas separations. The very challenging ethylene/ethane separation is the primary target of this work. Matrimid® derived CMS hollow fiber membranes have been investigated in this work. Resultant CMS fiber showed interesting separation performance for several gas pairs, especially high selectivity for C2H4/C2H6. Our comparative study between dense film and hollow fiber revealed very similar selectivity for both configurations; however, a significant difference exists in the effective separation layer thickness between precursor fibers and their resultant CMS fibers. SEM results showed that the deviation was essentially due to the collapse of the porous substructure of the precursor fiber. Polymer chain flexibility (relatively low glass transition temperature (Tg) for Matrimid® relative to actual CMS formation) appears to be the fundamental cause of substructure collapse. This collapse phenomenon must be addressed in all cases involving intense heat-treatment near or above Tg. We also found that the defect-free property of the precursor fiber was not a simple predictor of CMS fiber performance. Even some precursor fibers with Knudsen diffusion selectivity could be transformed into highly selective CMS fibers for the Matrimid® precursor. To overcome the permeance loss problem caused by substructure collapse, several engineering approaches were considered. Mixed gas permeation results under realistic conditions demonstrate the excellent performance of CMS hollow fiber membrane for the challenging ethylene/ethane separation. © 2011 Elsevier B.V.

  1. Square-lattice large-pitch hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Couny, F.; Roberts, John; Birks, T.A.

    2008-01-01

    We report on the design, fabrication and characterization of silica square-lattice hollow core photonic crystal fibers optimized for low loss guidance over an extended frequency range in the mid-IR region of the optical spectrum. The fiber's linear optical properties include an ultra-low group...... velocity dispersion and a polarization cross-coupling as low as -13.4dB over 10m of fiber....

  2. Formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes for gas separations

    KAUST Repository

    Xu, Liren

    2014-06-01

    This paper reports the formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes. 6FDA-polyimides are of great interest for advanced gas separation membranes, and 6FDA-DAM polyimide is a representative polymer in this family with attractive dense film properties for several potential applications. The work reported here for the 6FDA-DAM polyimide provides insight for the challenging fabrication of defect-free asymmetric hollow fiber membranes for this class of 6FDA-polyimides, which behave rather different from lower free volume polymers. Specifically, the 6FDA based materials show relatively slow phase separation rate in water quench baths, which presents a challenge for fiber spinning. For convenience, we refer to the behavior as more "non-solvent resistant" in comparison to other lower free volume polymers, since the binodal phase boundary is displaced further from the conventional position near the pure polymer-solvent axis on a ternary phase diagram in conventional polymers like Matrimid® and Ultem®. The addition of lithium nitrate to promote phase separation has a useful impact on 6FDA-DAM asymmetric hollow fiber formation. 6FDA-DAM phase diagrams using ethanol and water as non-solvent are reported, and it was found that water is less desirable as a non-solvent dope additive for defect-free fiber spinning. Phase diagrams are also reported for 6FDA-DAM dope formulation with and without the addition of lithium nitrate, and defect-free asymmetric hollow fiber membranes are reported for both cases. The effect of polymer molecular weight on defect-free fiber spinning was also investigated. Gas transport properties and morphology of hollow fibers were characterized. With several thorough case studies, this work provides a systematic guideline for defect-free fiber formation from 6FDA-polymers. © 2014 Elsevier B.V.

  3. Origin and suppression of parasitic signals in Kagomé lattice hollow core fibers used for SRS microscopy and endoscopy

    Science.gov (United States)

    Lombardini, Alberto; Andresen, Esben Ravn; Kudlinski, Alexandre; Rimke, Ingo; Rigneault, Hervé

    2017-05-01

    Hollow core fibers are considered as promising candidates to deliver intense temporally overlapping picosecond pulses in applications such as stimulated Raman scattering (SRS) microscopy and endoscopy because of their inherent low nonlinearity compared to solid-core silica fibers. Here we demonstrate that, contrary to prior assumptions, parasitic signals are generated in Kagom\\'e lattice hollow core fibers. We identify the origin of the parasitic signals as an interplay between the Kerr nonlinearity of air and frequency-dependent fiber losses. Importantly, we identify the special cases of experimental parameters that are free from parasitic signals, making hollow core fibers ideal candidates for noise-free SRS microscopy and endoscopy.

  4. Ultraviolet spectroscopic breath analysis using hollow-optical fiber as gas cell

    Science.gov (United States)

    Iwata, T.; Katagiri, T.; Matsuura, Y.

    2017-02-01

    For breath analysis on ultraviolet absorption spectroscopy, an analysis system using a hollow optical fiber as gas cell is developed. The hollow optical fiber functions as a long path and extremely small volume gas cell. Firstly, the measurement sensitivity of the system is evaluated by using NO gas as a gas sample. The result shows that NO gas with 50 ppb concentration is measured by using a system with a laser-driven, high intensity light source and a 3-meter long, aluminum-coated hollow optical fiber. Then an absorption spectrum of breath sample is measured in the wavelength region of around 200-300 nm and from the spectrum, it is found that the main absorbing components in breath were H2O, isoprene, and O3 converted from O2 by radiation of ultraviolet light. Then the concentration of isoprene in breath is estimated by using multiple linear regression analysis.

  5. Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid asymmetric hollow fiber membranes

    NARCIS (Netherlands)

    David, Oana C.; Gorri, Daniel; Nijmeijer, Dorothea C.; Ortiz, Inmaculada; Urtiaga, Ane

    2012-01-01

    The application of hollow fiber membranes for the separation of industrial gas mixtures relies on the correct characterization of the permeation of the involved gaseous components through the hollow fiber membranes. Thus, this study is focused on the characterization of the permeation through

  6. 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.

  7. Preparation and characterization of glass hollow fiber membrane for water purification applications.

    Science.gov (United States)

    Makhtar, Siti Nurfatin Nadhirah Mohd; Rahman, Mukhlis A; Ismail, Ahmad Fauzi; Othman, Mohd Hafiz Dzarfan; Jaafar, Juhana

    2017-07-01

    This work discusses the preparation and characterizations of glass hollow fiber membranes prepared using zeolite-5A as a starting material. Zeolite was formed into a hollow fiber configuration using the phase inversion technique. It was later sintered at high temperatures to burn off organic materials and change the zeolite into glass membrane. A preliminary study, that used thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared (FTIR), confirmed that zeolite used in this study changed to glass at temperatures above 1000 °C. The glass hollow fiber membranes prepared using the phase inversion technique has three different microstructures, namely (i) sandwich-like structure that originates from inner layer, (ii) sandwich-like that originates from outer layer, and (iii) symmetric sponge like. These variations were influenced by zeolite weight loading and the flow rate of water used to form the lumen. The separation performances of the glass hollow fiber membrane were studied using the pure water permeability and the rejection test of bovine serum albumin (BSA). The glass hollow fiber membrane prepared from using 48 wt% zeolite loading and bore fluid with 9 mL min -1 flow rate has the highest BSA rejection of 85% with the water permeability of 0.7 L m -2  h -1  bar -1 . The results showed that the separation performance of glass hollow fiber membranes was in the ultrafiltration range, enabled the retention of solutes with molecular sizes larger than 67 kDa such as milk proteins, endotoxin pyrogen, virus, and colloidal silica.

  8. Rapid Temperature Swing Adsorption using Polymeric/Supported Amine Hollow Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Chance, Ronald [Georgia Tech Research Corporation, Atlanta, GA (United States); Chen, Grace [Georgia Tech Research Corporation, Atlanta, GA (United States); Dai, Ying [Georgia Tech Research Corporation, Atlanta, GA (United States); Fan, Yanfang [Georgia Tech Research Corporation, Atlanta, GA (United States); Jones, Christopher [Georgia Tech Research Corporation, Atlanta, GA (United States); Kalyanaraman, Jayashree [Georgia Tech Research Corporation, Atlanta, GA (United States); Kawajiri, Yoshiaki [Georgia Tech Research Corporation, Atlanta, GA (United States); Koros, William [Georgia Tech Research Corporation, Atlanta, GA (United States); Lively, Ryan [Georgia Tech Research Corporation, Atlanta, GA (United States); McCool, Benjamin [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States); Realff, Matthew [Georgia Tech Research Corporation, Atlanta, GA (United States); Rezaei, Fateme [Georgia Tech Research Corporation, Atlanta, GA (United States); Searcy, Katherine [Georgia Tech Research Corporation, Atlanta, GA (United States); Sholl, David [Georgia Tech Research Corporation, Atlanta, GA (United States); Subramanian, Swernath [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-03-31

    This project is a bench-scale, post-combustion capture project carried out at Georgia Tech (GT) with support and collaboration with GE, Algenol Biofuels, Southern Company and subcontract to Trimeric Corporation. The focus of the project is to develop a process based on composite amine-functionalized oxide / polymer hollow fibers for use as contactors in a rapid temperature swing adsorption post-combustion carbon dioxide capture process. The hollow fiber morphology allows coupling of efficient heat transfer with effective gas contacting, potentially giving lower parasitic loads on the power plant compared to traditional contacting strategies using solid sorbents.

  9. Low-Loss Hollow-Core Anti-Resonant Fibers With Semi-Circular Nested Tubes

    DEFF Research Database (Denmark)

    Habib, Selim; Bang, Ole; Bache, Morten

    2016-01-01

    is quite insensitive to the curvature of the nested element, while the distance from the core boundary to the outer perimeter of the nested element is much more critical. Interestingly, the additional freedom of the semicircular nested elements allows optimizing them for a better loss performance than......Hollow-core fibers with a single ring of circular antiresonant tubes as the cladding provide a simple way of getting a negative-curvature hollow core, resulting in broadband low-loss transmission with little power overlap in the glass. These fibers show a significant improvement in loss performance...

  10. Fabrication of Polybenzimidazole/Palladium Nanoparticles Hollow Fiber Membranes for Hydrogen Purification

    KAUST Repository

    Villalobos, Luis Francisco

    2017-09-13

    A novel scheme to fabricate polybenzimidazole (PBI) hollow fiber membranes with a thin skin loaded with fully dispersed palladium nanoparticles is proposed for the first time. Palladium is added to the membrane during the spinning process in the form of ions that coordinate to the imidazole groups of the polymer. This is attractive for membrane production because agglomeration of nanoparticles is minimized and the high-cost metal is incorporated in only the selective layer—where it is required. Pd-containing membranes achieve three orders of magnitude higher H2 permeances and a twofold improvement in H2/CO2 selectivity compared to pure PBI hollow fiber membranes.

  11. Hollow Core Optical Fiber Gas Lasers: Toward Novel and Practical Systems in Fused Silica

    Science.gov (United States)

    2017-05-18

    release. John Luginsland Hollow-Core Optical Fiber Gas Lasers K. Corwin et al. 16 Fig. 18 (a) The mode- locked Tm/Ho...18. NUMBER OF PAGES 19a.  NAME OF RESPONSIBLE PERSON LUGINSLAND, JOHN 19b.  TELEPHONE NUMBER (Include area code) 703-588-1775 Standard Form 298 (Rev. 8...for public release. John Luginsland FA9550-14-1-0024 Final Report K. Corwin et al. 1 A. Project Summary/Abstract Hollow Core Optical Fiber Gas

  12. Fuel cell components and systems having carbon-containing electrically-conductive hollow fibers

    Science.gov (United States)

    Langry, Kevin C; Farmer, Joseph C

    2015-04-28

    A method, according to one embodiment, includes acquiring a structure having an ionically-conductive, electrically-resistive electrolyte/separator layer covering an inner or outer surface of a carbon-containing electrically-conductive hollow fiber and a catalyst along one side thereof, adding an anode that extends along at least part of a length of the structure, and adding a cathode that extends along at least part of the length of the structure, the cathode being on an opposite side of the hollow fiber as the anode.

  13. Hollow fiber membranes with different external corrugated surfaces for desalination by membrane distillation

    Science.gov (United States)

    García-Fernández, Loreto; García-Payo, Carmen; Khayet, Mohamed

    2017-09-01

    Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membranes were prepared using the phase inversion spinning technique under a wet gap mode. Different corrugated outer surfaces were obtained by means of a micro-engineered spinneret, spraying the external coagulant on the nascent fiber along gap, and different spinning parameters, namely, the gap distance and the external coagulant flow rate. A quantitative evaluation of the corrugation size and shape was carried out by electron scanning microscopy and atomic force microscopy. The effect of the corrugation size and shape on the direct contact membrane distillation (DCMD) performance has been studied. The corrugated outer surface acted as micro-turbulence promoters mitigating the temperature polarization effect and enhanced the external effective surface area for condensation. Both factors improved the DCMD permeability of the hollow fiber membranes. However, corrugations with V-shaped valleys depths greater than about 30 μm did not always improve the DCMD permeate flux. It was found that the membrane prepared with the spray wetting mode exhibited the best desalination performance. The salt rejection factor of all prepared hollow fiber membranes was greater than 99.9% and the highest DCMD permeate flux of this study was greater than those reported so far for the PVDF-HFP hollow fiber membranes.

  14. Optical fiber in-line Mach-Zehnder interferometer based on dual internal mirrors formed by a hollow sphere pair.

    Science.gov (United States)

    Hu, T Y; Wang, D N

    2013-08-15

    We demonstrate a fiber in-line Mach-Zehnder interferometer based on dual internal mirrors formed by a hollow sphere pair and fabricated by femtosecond laser micromachining together with the fusion splicing technique. The hollow sphere surface adjacent to the fiber core can reflect part of the incident light beam to the air-cladding interface, where the light beam is reflected again before returning to the fiber core by another hollow sphere surface and recombining with the light beam remaining in the fiber core. Such an interferometer is miniature and robust, and is sensitive to environmental variations and allows simultaneous surrounding refractive index, temperature, and curvature measurement.

  15. Carbon fiber composite molecular sieve electrically regenerable air filter media

    Science.gov (United States)

    Wilson, Kirk A.; Burchell, Timothy D.; Judkins, Roddie R.

    1998-01-01

    An electrically regenerable gas filter system includes a carbon fiber composite molecular sieve (CFCMS) filter medium. After a separate medium-efficiency pre-filter removes particulate from the supply airstream, the CFCMS filter sorbs gaseous air pollutants before the air is recirculated to the space. When saturated, the CFCMS media is regenerated utilizing a low-voltage current that is caused to pass through the filter medium.

  16. Kagome Hollow-Core Photonic Crystal Fiber Resonator for Rotation Sensing

    CERN Document Server

    Fsaifes, Ihsan; Debord, Benoît; Gérôme, Frédéric; Baz, Assaad; Humbert, Georges; Benabid, Fetah; Schwartz, Sylvain; Bretenaker, Fabien

    2016-01-01

    We investigate the performances of a Kagome Hollow-Core Photonic Crystal Fiber resonator for rotation sensing applications. The use of a large mode field diameter Kagome fiber permits to reduce the free space fiber-to-fiber coupling losses, allowing the realization of cavities with finesses compatible with the angular random walk required for medium to high performance rotation sensing, while minimizing the Kerr effect induced non reciprocities. Experiments show encouraging results that could lead to a compact, low cost, and robust medium for high performance gyroscope.

  17. Single-ring hollow core optical fibers made by glass billet extrusion for Raman sensing.

    Science.gov (United States)

    Tsiminis, G; Rowland, K J; Schartner, E P; Spooner, N A; Monro, T M; Ebendorff-Heidepriem, H

    2016-03-21

    We report the fabrication of the first extruded hollow core optical fiber with a single ring of cladding holes, and its use in a chemical sensing application. These single suspended ring structures show antiresonance reflection optical waveguiding (ARROW) features in the visible part of the spectrum. The impact of preform pressurization on the geometry of these fibers is determined by the size of the different hole types in the preform. The fibers are used to perform Raman sensing of methanol, demonstrating their potential for future fiber sensing applications.

  18. Beer Clarification by Novel Ceramic Hollow-Fiber Membranes: Effect of Pore Size on Product Quality.

    Science.gov (United States)

    Cimini, Alessio; Moresi, Mauro

    2016-10-01

    In this work, the crossflow microfiltration performance of rough beer samples was assessed using ceramic hollow-fiber (HF) membrane modules with a nominal pore size ranging from 0.2 to 1.4 μm. Under constant operating conditions (that is, transmembrane pressure difference, TMP = 2.35 bar; feed superficial velocity, vS = 2.5 m/s; temperature, T = 10 °C), quite small steady-state permeation fluxes (J* ) of 32 or 37 L/m2 /h were achieved using the 0.2- or 0.5-μm symmetric membrane modules. Both permeates exhibited turbidity beer quality parameters. Moreover, it exhibited J* values of the same order of magnitude of those claimed for the polyethersulfone HF membrane modules currently commercialized. The 1.4-μm asymmetric membrane module yielded quite a high steady-state permeation flux (196 ± 38 L/m2 /h), and a minimum decline in permeate quality parameters, except for the high levels of turbidity at room temperature and chill haze. In the circumstances, such a membrane module might be regarded as a real valid alternative to conventional powder filters on condition that the resulting permeate were submitted to a final finishing step using 0.45- or 0.65-μm microbially rated membrane cartridges prior to aseptic bottling. A novel combined beer clarification process was thus outlined. © 2016 Institute of Food Technologists®.

  19. Increasing the Performance of Vacuum Membrane Distillation Using Micro-Structured Hydrophobic Aluminum Hollow Fiber Membranes

    Directory of Open Access Journals (Sweden)

    Chia-Chieh Ko

    2017-04-01

    Full Text Available This study develops a micro-structured hydrophobic alumina hollow fiber with a high permeate flux of 60 Lm−2h−1 and salt rejection over 99.9% in a vacuum membrane distillation process. The fiber is fabricated by phase inversion and sintering, and then modified with fluoroalkylsilanes to render it hydrophobic. The influence of the sintering temperature and feeding temperature in membrane distillation (MD on the characteristics of the fiber and MD performance are investigated. The vacuum membrane distillation uses 3.5 wt % NaCl aqueous solution at 70 °C at 0.03 bar. The permeate flux of 60 Lm−2h−1 is the highest, compared with reported data and is higher than that for polymeric hollow fiber membranes.

  20. Silica hollow core microstructured fibers for beam delivery in industrial and medical applications

    Directory of Open Access Journals (Sweden)

    Jonathan Dale Shephard

    2015-04-01

    Full Text Available The focus of this review is our recent work to develop microstructured hollow core fibers for two applications where the flexible delivery of a single mode beam is desired. Also, a review of other fiber based solutions is included.High power, short-pulsed lasers are widely used for micro-machining, providing high precision and high quality. However, the lack of truly flexible beam delivery systems limits their application to the processing of relatively small planar components. To address this, we developed hollow-core optical fibers for the 1 μm and green wavelength ranges. The hollow core overcomes the power delivery limitations of conventional silica fibers arising from nonlinear effects and material damage in the solid core. We have characterized such fibers in terms of power handling capability, damage threshold, bend loss and dispersion, and practically demonstrated delivery of high peak power pulses from the nanosecond to the femtosecond regime. Such fibers are ideal candidates for industrial laser machining applications.In laser surgical applications, meanwhile, an Er:YAG laser (2.94 μm is frequently the laser of choice because the water contained in tissue strongly absorbs this wavelength. If this laser beam is precisely delivered damage to surrounding tissue can be minimized. A common delivery method of surgical lasers, for use in the operating theatre, is articulated arms that are bulky, cumbersome and unsuitable for endoscopic procedures. To address this need for flexible mid-IR delivery we developed silica based hollow core fibers. By minimizing the overlap of the light with glass it is possible to overcome the material absorption limits of silica and achieve low attenuation. Additionally, it is possible to deliver pulse energies suitable for the ablation of both hard and soft tissue even with very small bend radii. The flexibility and small physical size of systems based on these fibers will enable new minimally invasive surgical

  1. Blood glucose measurement by using hollow optical fiber-based attenuated total reflection probe

    Science.gov (United States)

    Kino, Saiko; Tanaka, Yuki; Matsuura, Yuji

    2014-05-01

    A noninvasive glucose monitoring system based on mid-infrared, attenuated total reflection spectroscopy using a hollow optical fiber probe is developed. Owing to the flexible fiber probe, measurement of oral mucosa, where blood capillaries are near the skin surface, is possible. Blood glucose levels are measured by detecting the peak intensity of glucose absorption bands, and the experimental results showed that the reproducibility of the measurement is high enough for monitoring blood glucose.

  2. Silica hollow core microstructured fibers for beam delivery in industrial and medical applications

    Science.gov (United States)

    Shephard, Jonathan; Urich, Artur; Carter, Richard; Jaworski, Piotr; Maier, Robert; Belardi, Walter; Yu, Fei; Wadsworth, William; Knight, Jonathan; Hand, Duncan

    2015-04-01

    The focus of this review is our recent work to develop microstructured hollow core fibers for two applications where the flexible delivery of a single mode beam is desired. Also, a review of other fiber based solutions is included. High power, short-pulsed lasers are widely used for micro-machining, providing high precision and high quality. However, the lack of truly flexible beam delivery systems limits their application to the processing of relatively small planar components. To address this, we developed hollow-core optical fibers for the 1 μm and green wavelength ranges. The hollow core overcomes the power delivery limitations of conventional silica fibers arising from nonlinear effects and material damage in the solid core. We have characterized such fibers in terms of power handling capability, damage threshold, bend loss and dispersion, and practically demonstrated delivery of high peak power pulses from the nanosecond to the femtosecond regime. Such fibers are ideal candidates for industrial laser machining applications. In laser surgical applications, meanwhile, an Er:YAG laser (2.94 μm) is frequently the laser of choice because the water contained in tissue strongly absorbs this wavelength. If this laser beam is precisely delivered damage to surrounding tissue can be minimized. A common delivery method of surgical lasers, for use in the operating theatre, is articulated arms that are bulky, cumbersome and unsuitable for endoscopic procedures. To address this need for flexible mid-IR delivery we developed silica based hollow core fibers. By minimizing the overlap of the light with glass it is possible to overcome the material absorption limits of silica and achieve low attenuation. Additionally, it is possible to deliver pulse energies suitable for the ablation of both hard and soft tissue even with very small bend radii. The flexibility and small physical size of systems based on these fibers will enable new minimally invasive surgical procedures.

  3. Nonlinear optics at the single-photon level inside a hollow core fiber

    DEFF Research Database (Denmark)

    Hofferberth, Sebastian; Peyronel, Thibault; Liang, Qiyu

    2011-01-01

    Cold atoms inside a hollow core fiber provide an unique system for studying optical nonlinearities at the few-photon level. Confinement of both atoms and photons inside the fiber core to a diameter of just a few wavelengths results in high electric field intensity per photon and large optical...... depths with a relatively small number of atoms. We present our experimental apparatus and discuss results regarding all-optical switching at ultra-low light levels....

  4. Study on surface adhesion of Plasma modified Polytetrafluoroethylene hollow fiber membrane

    Science.gov (United States)

    Chen, Jiangrong; Zhang, Huifeng; Liu, Guochang; Guo, Chungang; Lv, Jinglie; Zhangb, Yushan

    2018-01-01

    Polytetrafluoroethylene (PTFE) is popular membrane material because of its excellent thermal stability, chemical stability and mechanical stability. However, the low surface energy and non-sticky property of PTFE present challenges for modification. In the present study, plasma treatment was performed to improve the surface adhesion of PTFE hollow fiber membrane. The effect of discharge voltage, treatment time on the adhesion of PTFE hollow fiber membrane was symmetrically evaluated. Results showed that the plasma treatment method contributed to improve the surface activity and roughness of PTFE hollow fiber membrane, and the adhesion strength depend significantly on discharge voltage, which was beneficial to seepage pressure of PTFE hollow fiber membrane module. The adhesion strength of PTFE membrane by plasma treated at 220V for 3min reached as high as 86.2 N, far surpassing the adhesion strength 12.7 N of pristine membrane. Furthermore, improvement of content of free radical and composition analysis changes of the plasma modified PTFE membrane were investigated. The seepage pressure of PTFE membrane by plasma treated at 220V for 3min was 0.375 MPa, which means that the plasma treatment is an effective technique to improve the adhesion strength of membrane.

  5. CO2 absorption at elevated pressures using a hollow fiber membrane contactor

    NARCIS (Netherlands)

    Dindore, V.Y.; Brilman, D.W.F.; Feron, P.H.M.; Versteeg, G.F.

    2004-01-01

    Recently, hollow fiber membrane gas–liquid contactor-based processes have gained an increasing attention. Compared to conventional processes, these processes have numerous advantages. The membrane contactors provide a very high interfacial area per unit volume, independent regulation of gas and

  6. Composite hollow fiber membranes for organic solvent-based liquid-liquid extraction

    NARCIS (Netherlands)

    He, T.; Bolhuis-Versteeg, Lydia A.M.; Mulder, M.H.V.; Wessling, Matthias

    2004-01-01

    Instability issues of liquid membranes extraction significantly limit its wide application in industry. We report research on the application of a new composite hollow fiber membrane to stabilizing liquid membrane extraction. These type of composite membranes have either a polysulfone (PSf)

  7. Preparation of Porous Hollow Fiber Membranes with a Triple-Orifice Spinneret

    NARCIS (Netherlands)

    He, T.; Mulder, M.H.V.; Wessling, Matthias

    2003-01-01

    A triple-orifice spinneret has been applied for the preparation of hollow fiber microfiltration membranes with a high surface porosity. Considering the general rules of diffusion induced phase separation, a low polymer concentration is required at the outer layer to obtain a highly interconnected

  8. Preparation of multifunctional hollow fiber nanofiltration membranes by dynamic assembly of weak polyelectrolyte multilayers

    NARCIS (Netherlands)

    Ilyas, Shazia; English, Renee; Aimar, Pierre; Lahitte, Jean-Francois; de Vos, Wiebe Matthijs

    2017-01-01

    In this work, we investigate the effect of preparation conditions for dynamic layer-by-layer (LbL) coating, to prepare multifunctional hollow fiber nanofiltration (NF) membranes. Dynamic coating was performed at constant pressure and at variable cross flow speeds. In this way, polyelectrolyte

  9. Weak polyelectrolyte multilayers as tunable separation layers for micropollutant removal by hollow fiber nanofiltration membranes

    NARCIS (Netherlands)

    Ilyas, Shazia; Abtahi, S. Mehran; Akkilic, Namik; Roesink, H. D. W.; de Vos, Wiebe M.

    2017-01-01

    The presence of micro-pollutants in wastewater and in drinking water and its sources, is posing both environmental and health concerns. This work describes the development of weak polyelectrolyte multilayer (PEM) based hollow fiber nanofiltration (NF) membranes to remove micro-pollutants from

  10. Humidity control during bell pepper storage, using a hollow fiber membrane contractor system

    NARCIS (Netherlands)

    Dijkink, B.H.; Tomassen, M.M.M.; Willemsen, J.H.A.; Doorn, van W.G.

    2004-01-01

    Green bell peppers (Capsicum annuum cv. Cardio) were stored in open crates at 5 degreesC, using a novel system for maintenance of relative humidity (RH). A hollow fiber membrane contactor allowed adequate transfer of water vapor between the air in the storage room and a liquid desiccant. The

  11. Particle-loaded hollow-fiber membrane adsorbers for lysozyme separation

    NARCIS (Netherlands)

    Avramescu, M.E.; Borneman, Zandrie; Wessling, Matthias

    2008-01-01

    The separation of lysozyme (LZ), a valuable enzyme naturally present in chicken egg white, was carried out using a new type of ion exchange hollow-fiber membranes. Functionalities were incorporated into the polymeric membranes by dispersing ion-exchange resins (IERs) in a microporous structure

  12. Hollow fiber dead-end ultrafiltration: Axial transport variations during humic acid filtration

    NARCIS (Netherlands)

    van de Ven, W.J.C.; van 't Sant, K.; Punt, Ineke G.M.; Zwijnenburg, A.; Kemperman, Antonius J.B.; van der Meer, Walterus Gijsbertus Joseph; Wessling, Matthias

    2008-01-01

    This paper describes the dead-end ultrafiltration of humic substances with hollow fiber modules. We show that the resistance of a fouling layer decreases with increasing flux. The lower resistance of the fouling layer is caused by a loss in retention of the membrane for humic acid at these higher

  13. Membrane distillation with porous metal hollow fibers for the concentration of thermo-sensitive solutions

    NARCIS (Netherlands)

    Shukla, Sushumna

    2014-01-01

    This thesis presents an original approach for the concentration of thermo-sensitive solutions: the Sweep Gas Membrane Distillation (SGMD) process. A new membrane contactor with metallic hollow fibers has been designed and allows the distillation process to be operational at low temperature. Heat is

  14. Characterization of hollow fiber hemo-dialysis membranes: pore size distribution and performance

    NARCIS (Netherlands)

    Broek, A.P.; Broek, Arnold P.; Teunis, Herman A.; Teunis, Hermannus A.; Bargeman, D.; Bargeman, Derk; Sprengers, Erik D.; Smolders, C.A.; Smolders, C.A.

    1992-01-01

    The effect of two commonly used sterilization methods for artificial kidneys on the morphology and performance of hollow fiber Hemophan® hemodialysis membranes was studied. A relatively new membrane characterization method, thermoporometry, was used to determine the pore size distributions and

  15. Slow-light enhanced absorption in a hollow-core fiber

    DEFF Research Database (Denmark)

    Grgic, Jure; Xiao, Sanshui; Mørk, Jesper

    2010-01-01

    Light traversing a hollow-core photonic band-gap fiber may experience multiple reflections and thereby a slow-down and enhanced optical path length. This offers a technologically interesting way of increasing the optical absorption of an otherwise weakly absorbing material which can infiltrate...

  16. Design of low-loss and highly birefringent hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Roberts, Peter John; Williams, D.P.; Sabert, H.

    2006-01-01

    A practical hollow-core photonic crystal fiber design suitable for attaining low-loss propagation is analyzed. The geometry involves a number of localized elliptical features positioned on the glass ring that surrounds the air core and separates the core and cladding regions. The size of each fea...

  17. Porous stainless steel hollow fibers with shrinkage-controlled small radial dimensions

    NARCIS (Netherlands)

    Luiten-Olieman, Maria W.J.; Raaijmakers, Michiel; Raaijmakers, Michiel J.T.; Winnubst, Aloysius J.A.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

    2011-01-01

    A method is presented for the preparation of thin (∼250 μm) porous stainless steel hollow fiber membranes based on dry–wet spinning of a particle-loaded polymer solution followed by heat treatment. Extraordinarily small radial dimensions were achieved by controlled shrinkage during thermal

  18. Efficient all-optical switching using slow light within a hollow fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Balic, Vlatko

    2009-01-01

    We demonstrate a fiber-optical switch that is activated at tiny energies corresponding to a few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic-crys...

  19. An Experiment to Introduce Mass Transfer Concepts Using a Commercial Hollow Fiber Blood Oxygenator

    Science.gov (United States)

    McIver, Keith; Merrill, Thomas; Farrell, Stephanie

    2017-01-01

    A commercial hollow fiber blood oxygenation laboratory experiment was used to introduce lower level engineering students to mass balances in a two-phase system. Using measured values of concentration and flow rate, students calculated the rate of mass transfer from the gas phase and into the liquid phase, and compared the two values to determine…

  20. Analysis of propagation properties of terahertz hollow-optical fiber by using time-domain spectroscopy and application for THz wave remote spectroscopy

    Science.gov (United States)

    Ito, K.; Katagiri, T.; Matsuura, Y.

    2017-02-01

    Terahertz pulse propagation in hollow optical fibers is investigated by using terahertz time-domain spectroscopy. From evaluation of transmission loss spectra of hollow optical fiber, it is found that TM11 mode propagates as well as TE11 mode that is the lowest order mode in terahertz metal-hollow fiber. Short-time Fourier transform is also applied for investigation of mode properties and as a result, it is confirmed that the interference peaks in the loss spectra are due to mode mixing in hollow optical fibers. Finally we performed a terahertz wave remote spectroscopy using the hollow optical fiber and acquired a clear transmission spectrum of the theophylline.

  1. Hollow-core optical fiber incorporating a metamaterial cladding

    DEFF Research Database (Denmark)

    2010-01-01

    An optical fiber (100, 200, 300) for guidance of electromagnetic radiation with an operational wavelength l, the fiber (100, 200, 300) having a longitudinal direction along a longitudinal axis and a transverse direction in a plane perpendicular to the longitudinal axis, the fiber (100, 200, 300...

  2. Application of Negative Curvature Hollow-Core Fiber in an Optical Fiber Sensor Setup for Multiphoton Spectroscopy

    Directory of Open Access Journals (Sweden)

    Maciej Andrzej Popenda

    2017-10-01

    Full Text Available In this paper, an application of negative curvature hollow core fiber (NCHCF in an all-fiber, multiphoton fluorescence sensor setup is presented. The dispersion parameter (D of this fiber does not exceed the value of 5 ps/nm × km across the optical spectrum of (680–750 nm, making it well suited for the purpose of multiphoton excitation of biological fluorophores. Employing 1.5 m of this fiber in a simple, all-fiber sensor setup allows us to perform multiphoton experiments without any dispersion compensation methods. Multiphoton excitation of nicotinamide adenine dinucleotide (NADH and flavin adenine dinucleotide (FAD with this fiber shows a 6- and 9-fold increase, respectively, in the total fluorescence signal collected when compared with the commercial solution in the form of a hollow-core photonic band gap fiber (HCPBF. To the author’s best knowledge, this is the first time an NCHCF was used in an optical-fiber sensor setup for multiphoton fluorescence experiments.

  3. Application of Negative Curvature Hollow-Core Fiber in an Optical Fiber Sensor Setup for Multiphoton Spectroscopy

    Science.gov (United States)

    Stawska, Hanna Izabela; Mazur, Leszek Mateusz; Kosolapov, Alexey; Kolyadin, Anton; Bereś-Pawlik, Elżbieta

    2017-01-01

    In this paper, an application of negative curvature hollow core fiber (NCHCF) in an all-fiber, multiphoton fluorescence sensor setup is presented. The dispersion parameter (D) of this fiber does not exceed the value of 5 ps/nm × km across the optical spectrum of (680–750) nm, making it well suited for the purpose of multiphoton excitation of biological fluorophores. Employing 1.5 m of this fiber in a simple, all-fiber sensor setup allows us to perform multiphoton experiments without any dispersion compensation methods. Multiphoton excitation of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) with this fiber shows a 6- and 9-fold increase, respectively, in the total fluorescence signal collected when compared with the commercial solution in the form of a hollow-core photonic band gap fiber (HCPBF). To the author’s best knowledge, this is the first time an NCHCF was used in an optical-fiber sensor setup for multiphoton fluorescence experiments. PMID:28984838

  4. Thermally moderated hollow fiber sorbent modules in rapidly cycled pressure swing adsorption mode for hydrogen purification

    KAUST Repository

    Lively, Ryan P.

    2012-10-01

    We describe thermally moderated multi-layered pseudo-monolithic hollow fiber sorbents entities, which can be packed into compact modules to provide small-footprint, efficient H2 purification/CO2 removal systems for use in on-site steam methane reformer product gas separations. Dual-layer hollow fibers are created via dry-jet, wet-quench spinning with an inner "active" core of cellulose acetate (porous binder) and zeolite NaY (69 wt% zeolite NaY) and an external sheath layer of pure cellulose acetate. The co-spun sheath layer reduces the surface porosity of the fiber and was used as a smooth coating surface for a poly(vinyl-alcohol) post-treatment, which reduced the gas permeance through the fiber sorbent by at least 7 orders of magnitude, essentially creating an impermeable sheath layer. The interstitial volume between the individual fibers was filled with a thermally-moderating paraffin wax. CO2 breakthrough experiments on the hollow fiber sorbent modules with and without paraffin wax revealed that the "passively" cooled paraffin wax module had 12.5% longer breakthrough times than the "non-isothermal" module. The latent heat of fusion/melting of the wax offsets the released latent heat of sorption/desorption of the zeolites. One-hundred rapidly cycled pressure swing adsorption cycles were performed on the "passively" cooled hollow fiber sorbents using 25 vol% CO2/75 vol% He (H2 surrogate) at 60 °C and 113 psia, resulting in a product purity of 99.2% and a product recovery of 88.1% thus achieving process conditions and product quality comparable to conventional pellet processes. Isothermal and non-isothermal dynamic modeling of the hollow fiber sorbent module and a traditional packed bed using gPROMS® indicated that the fiber sorbents have sharper fronts (232% sharper) and longer adsorbate breakthrough times (66% longer), further confirming the applicability of the new fiber sorbent approach for H2 purification. © 2012, Hydrogen Energy Publications, LLC

  5. Modeling of hydrodynamics in hollow fiber membrane bioreactor for mammalian cells cultivation

    Directory of Open Access Journals (Sweden)

    N. V. Menshutina

    2016-01-01

    Full Text Available The mathematical modelling in CFD-packages are powerfull instrument for design and calculation of any engineering tasks. CFD-package contains the set of programs that allow to model the different objects behavior based on the mathematical lows. ANSYS Fluent are widely used for modelling of biotechnological and chemical-technological processes. This package is convenient to describe their hydrodynamics. As cell cultivation is one of the actual scientific direction in modern biotechnology ANSYS Fluent was used to create the model of hollow fiber membrane bioreactor. The fibers are hollow cylindrical membrane to be used for cell cultivation. The criterion of process effectiveness for cell growth is full filling of the membrane surface by cells in the bioreactor. While the cell growth the fiber permeability is decreased which effects to feed flow through membrane pores. The specific feature of this process is to ensure such feed flow to deliver the optimal nutrition for the cells on the external membrane surface. The velocity distribution inside the fiber and in all bioreactor as a whole has been calculated based on mass an impulse conservation equations taking into account the mathematical model assumptions. The hydrodynamics analysis in hollow fiber membrane bioreactor is described by the three-dimensional model created in ANSYS Fluent. The specific features of one membrane model are considered and for whole bioreactor too.

  6. Guiding Properties of Silica/Air Hollow-Core Bragg Fibers

    DEFF Research Database (Denmark)

    Foroni, Matteo; Passaro, Davide; Poli, Federica

    2008-01-01

    The guiding properties of realistic silica/air hollow-core Bragg fibers have been investigated by calculating the dispersion curves, the confinement loss spectrum and the field distribution of the guided modes through a full-vector modal solver based on the finite element method. In particular......, the silica bridge influence on the fundamental mode has been analyzed, by comparing the properties of an ideal structure, without the silica nano-supports, and of two realistic fibers, with squared off and rounded air-holes. Simulation results have demonstrated the presence of anti-crossing points...... on the guiding properties of each geometric characteristic in the hollow-core Bragg fiber cross-section has been deeply investigated, thus showing which parameter it is better to change in order to properly modify the loss values or its spectral behaviour. Moreover, in order to improve the loss properties...

  7. The optical properties of quantum dots integrated in a hollow core photon crystal fiber

    Science.gov (United States)

    Pidenko, Sergei A.; Burmistrova, Natalia A.; Pidenko, Pavel S.; Bondarenko, Sergei D.; Shuvalov, Andrei A.; Chibrova, Anastasiya A.; Skibina, Yulia S.; Goryacheva, Irina Y.

    2017-03-01

    The use of photonic crystal fibers as a basis elements for biosensor construction is a perspective trend. The advantages of this approach are the use of micro and nano volumes of samples and a significant strengthening of the analytical signal while increasing the optical path length. Quantum dots are the most promising fluorescent markers for use in the photonic crystal fibers based analysis. The advantages of quantum dots, in this case, are associated with stability, wide range of excitation and extremely narrow range of high luminescence intensity. In this work we have investigated the behavior and optical properties of CdSe core-shell nanocrystals (quantum dots) after they including into hollow central defect of hollow core chirped photonic crystal fibers with internal surface modified by polyaniline films.

  8. Dual membrane hollow fiber fuel cell and method of operating same

    Science.gov (United States)

    Ingham, J. D.; Lawson, D. D. (Inventor)

    1978-01-01

    A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolytes and electrically connected. As hydrogen and oxygen flow through the bore of the fibers, oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained.

  9. Laser-cooled atoms inside a hollow-core photonic-crystal fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Peyronel, Thibault

    2011-01-01

    We describe the loading of laser-cooled rubidium atoms into a single-mode hollow-core photonic-crystal fiber. Inside the fiber, the atoms are confined by a far-detuned optical trap and probed by a weak resonant beam. We describe different loading methods and compare their trade-offs in terms...... of implementation complexity and atom-loading efficiency. The most efficient procedure results in loading of ∼30,000 rubidium atoms, which creates a medium with an optical depth of ∼180 inside the fiber. Compared to our earlier study this represents a sixfold increase in the maximum achieved optical depth...

  10. Fresnel-Reflection-Free Self-Aligning Nanospike Interface between a Step-Index Fiber and a Hollow-Core Photonic-Crystal-Fiber Gas Cell

    Science.gov (United States)

    Pennetta, Riccardo; Xie, Shangran; Lenahan, Frances; Mridha, Manoj; Novoa, David; Russell, Philip St. J.

    2017-07-01

    We report a fully integrated interface delivering efficient, reflection-free, single-mode, and self-aligned coupling between a step-index fiber and a gas-filled hollow-core photonic crystal fiber. The device offers a universal solution for interfacing solid and hollow cores and can be sealed to allow operation either evacuated or at high pressure. Stimulated Raman scattering and molecular modulation of light are demonstrated in a H2 -filled hollow-core photonic crystal fiber using the device.

  11. Hollow-core infrared fiber incorporating metal-wire metamaterial

    DEFF Research Database (Denmark)

    Yan, Min; Mortensen, Asger

    2009-01-01

    waveguides usually use a layer of metallic coating on the inner wall of the waveguide. Such a metallic layer, though reflective, still absorbs guided light significantly due to its finite Ohmic loss, especially for transverse-magnetic (TM) light. In this paper, we show that metal-wire based metamaterials may......Infrared (IR) light is considered important for short-range wireless communication, thermal sensing, spectroscopy, material processing, medical surgery, astronomy etc. However, IR light is in general much harder to transport than optical light or microwave radiation. Existing hollow-core IR...

  12. Ultra-large bandwidth hollow-core guiding in all-silica bragg fibers with nano-supports

    DEFF Research Database (Denmark)

    Vienne, Guillaume; Xu, Yong; Jakobsen, Christian

    2004-01-01

    We demonstrate a new class of hollow-core Bragg fibers that are composed of concentric cylindrical silica rings separated by nanoscale support bridges. We theoretically predict and experimentally observe hollow-core confinement over an octave frequency range. The bandwidth of bandgap guiding...

  13. Microbial degradation of phenol in high-salinity solutions in suspensions and hollow fiber membrane contactors.

    Science.gov (United States)

    Juang, Ruey-Shin; Wu, Cheng-Ying

    2007-01-01

    A microporous polypropylene (PP) hollow fiber membrane contactor was used as a bioreactor to degrade phenol in aqueous solutions by Pseudomonas putida BCRC 14365 at 30 degrees C. The fibers were pre-wetted by ethanol to make them more hydrophilic. The initial cell density was fixed at 0.025 gl(-1). The effects of added NaCl concentration (0-1.78 M) and pH (3-8) in substrate solution on the biodegradation were studied. The experimental results by suspended cells were discussed. It was shown that the cells in microporous hollow fibers were unable to tolerate substrate solution pH to a larger range than those in suspensions. The suspended cells grew well on 100 mg l(-1) of phenol only at NaCl concentrations below 0.44 M. However, the cells in microporous hollow fibers could completely degrade 500 mg l(-1) of phenol in solutions containing NaCl concentration up to 1.52 M, which was due to the enhanced tolerance limit to salinity effect by the membrane-attached biofilms and the sufficiently slow mass transfer of NaCl through the membrane pores.

  14. Ultem®/ZIF-8 mixed matrix hollow fiber membranes for CO2/N2 separations

    KAUST Repository

    Dai, Ying

    2012-05-01

    Organic-inorganic hybrid (mixed matrix) membranes can potentially extend the separation performance of traditional polymeric materials while maintaining processing convenience. Although many dense films studies have been reported, there have been few reported cases of these materials being successfully extended to asymmetric hollow fibers. In this work we report the first successful production of mixed matrix asymmetric hollow fiber membranes containing metal-organic-framework (MOF) ZIF-8 fillers. Specifically, we have incorporated ZIF-8 into a polyetherimide (Ultem ® 1000) matrix and produced dual-layer asymmetric hollow fiber membranes via the dry jet-wet quench method. The outer separating layer of these composite fibers contains 13wt% (17vol%) of ZIF-8 filler. These membranes have been tested over a range of temperatures and pressures for a variety of gas pairs. An increase in separation performance for the CO 2/N 2 gas pairs was observed for both pure gas and mixed gas feeds. © 2012 Elsevier B.V.

  15. The evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matrices

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data to support the evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water...

  16. Pressure-assisted synthesis of HKUST-1 thin film on polymer hollow fiber at room temperature toward gas separation.

    Science.gov (United States)

    Mao, Yiyin; Li, Junwei; Cao, Wei; Ying, Yulong; Sun, Luwei; Peng, Xinsheng

    2014-03-26

    The scalable fabrication of continuous and defect-free metal-organic framework (MOF) films on the surface of polymeric hollow fibers, departing from ceramic supported or dense composite membranes, is a huge challenge. The critical way is to reduce the growth temperature of MOFs in aqueous or ethanol solvents. In the present work, a pressure-assisted room temperature growth strategy was carried out to fabricate continuous and well-intergrown HKUST-1 films on a polymer hollow fiber by using solid copper hydroxide nanostrands as the copper source within 40 min. These HKUST-1 films/polyvinylidenefluoride (PVDF) hollow fiber composite membranes exhibit good separation performance for binary gases with selectivity 116% higher than Knudsen values via both inside-out and outside-in modes. This provides a new way to enable for scale-up preparation of HKUST-1/polymer hollow fiber membranes, due to its superior economic and ecological advantages.

  17. Hollow fiber-supported designer ionic liquid sponges for post-combustion CO2 scrubbing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, JS; Hillesheim, PC; Huang, DK; Lively, RP; Oh, KH; Dai, S; Koros, WJ

    2012-11-30

    A proof of concept study for a new type of carbon capture system is considered for post-combustion CO2 capture based on porous hollow fiber sorbents with ionic liquids sorbed in the cell walls of the fiber. This study proves that delicate morphological features in the open-celled porous wall can be maintained during the infusion process. Mixtures of task specific ionic liquid (i.e. [BMIM][Tf2N]) and superbase (i.e. DBU) were loaded into polyamide-imide (PAI) fibers by a so-called two-step non-solvent infusion protocol. In the protocol, methanol carries ionic liquids into the pore cell walls of hollow fibers and then hexane carries superbase to create an efficient CO2 sorbent. Our ionic liquid/superbase impregnation technique overcomes a serious increase in mass transfer resistance upon reaction with CO2, thereby allowing its large scale utilization for post-combustion CO2 capture. The investigation on the effect of different pore former additives (different molecular weights of polyvinylpyrrolidone, lithium nitrate, and their mixtures) suggested that a large molecular weight of PVP (M-w; 1300k) including dope composition produces highly interconnected open cell pore structures of PAI hollow fibers. Lastly, a lumen side barrier layer was successfully formed on the bore side of neat PAI fibers by using a mixture of Neoprene (R) with crosslinking agents (TSR-633) via a post-treatment process. The lumen layer will enable heat removal from the fiber sorbents during their application in rapid thermal swing cycling processes. (C) 2012 Elsevier Ltd. All rights reserved.

  18. Plasticization-resistant hollow fiber membranes for CO2/CH4 separation based on a thermally crosslinkable polyimide

    KAUST Repository

    Chen, Chien-Chiang

    2011-10-01

    Decarboxylation-induced thermal crosslinking has been demonstrated to be effective for stabilizing membranes against plasticization in dense films. This study extends this promising crosslinking approach from dense films to industrially relevant asymmetric hollow fiber membranes. Crosslinkable asymmetric hollow fiber membranes were spun from a carboxylic acid containing polyimide, 6FDA-DAM:DABA. Dope and spinning conditions were optimized to obtain fibers with a defect-free selective skin layer. It is found that slightly defective fibers suffered severe selectivity loss after thermal crosslinking, suggesting that defect-free property is essential to the performance of the resulting crosslinked hollow fiber membranes. The crosslinked fibers were tested for CO 2/CH 4 separation. The excellent plasticization resistance under high pressure feeds (with highest CO 2 partial pressure of 400psia) suggests that these robust membranes are promising for aggressive natural gas purification. © 2011 Elsevier B.V.

  19. Antiresonant guiding in a poly(methyl-methacrylate) hollow-core optical fiber

    DEFF Research Database (Denmark)

    Markos, Christos; Nielsen, Kristian; Bang, Ole

    2015-01-01

    Strong antiresonant reflecting optical waveguiding is demonstrated in a novel poly (methyl-methacrylate) (PMMA) hollow-core fiber. The transmission spectrum of the fiber was characterized using a supercontinuum source and it revealed distinct resonances with resonant dips as strong as ~20 d......B in the wavelength range 480-900 nm, where PMMA has low absorption. The total propagation loss of the fiber was measured to have a minimum of ~45 dB m-1 at around 500 nm. The thermal sensitivity of the fiber is 256 ± 16 pm °C-1, defined as the red-shift of the resonances per °C, which is three times higher than...... the sensitivity of polymer fiber Bragg gratings....

  20. Antiresonant guiding in a poly(methyl-methacrylate) hollow-core optical fiber

    Science.gov (United States)

    Markos, Christos; Nielsen, Kristian; Bang, Ole

    2015-10-01

    Strong antiresonant reflecting optical waveguiding is demonstrated in a novel poly (methyl-methacrylate) (PMMA) hollow-core fiber. The transmission spectrum of the fiber was characterized using a supercontinuum source and it revealed distinct resonances with resonant dips as strong as ˜20 dB in the wavelength range 480-900 nm, where PMMA has low absorption. The total propagation loss of the fiber was measured to have a minimum of ˜45 dB m-1 at around 500 nm. The thermal sensitivity of the fiber is 256 ± 16 pm °C-1, defined as the red-shift of the resonances per °C, which is three times higher than the sensitivity of polymer fiber Bragg gratings.

  1. Recent progress on gas sensor based on quantum cascade lasers and hollow fiber waveguides

    Science.gov (United States)

    Liu, Ningwu; Sun, Juan; Deng, Hao; Ding, Junya; Zhang, Lei; Li, Jingsong

    2017-02-01

    Mid-infrared laser spectroscopy provides an ideal platform for trace gas sensing applications. Despite this potential, early MIR sensing applications were limited due to the size of the involved optical components, e.g. light sources and sample cells. A potential solution to this demand is the integration of hollow fiber waveguide with novelty quantum cascade lasers.Recently QCLs had great improvements in power, efficiency and wavelength range, which made the miniaturized platforms for gas sensing maintaining or even enhancing the achievable sensitivity conceivable. So that the miniaturization of QCLs and HWGs can be evolved into a mini sensor, which may be tailored to a variety of real-time and in situ applications ranging from environmental monitoring to workplace safety surveillance. In this article, we introduce QCLs and HWGs, display the applications of HWG based on QCL gas sensing and discuss future strategies for hollow fiber coupled quantum cascade laser gas sensor technology.

  2. Effects of CO 2 on a High Performance Hollow-Fiber Membrane for Natural Gas Purification

    KAUST Repository

    Omole, Imona C.

    2010-05-19

    A 6FDA-based, cross-linkable polyimide was characterized in the form of a defect-free asymmetric hollow-fiber membrane. The novel membrane was cross-linked at various temperatures and tested for natural gas purification in the presence of high CO2 partial pressures. The cross-linked membrane material shows high intrinsic separation performance for CO2 and CH4 (selectivity ∼49, CO2 permeability ∼161 barrer, with a feed at 65 psia, 35 °C, and 10% CO2). Cross-linked asymmetric hollow-fiber membranes made from the material show good resistance to CO2-induced plasticization. Carbon dioxide partial pressures as high as ∼400 psia were employed, and the membrane was shown to be promisingly stable under these aggressive conditions. The performance of the membrane was also analyzed using the dual-mode sorption/transport model. © 2010 American Chemical Society.

  3. Feasibility study of Zeeman modulation spectrometry with a hollow capillary fiber based gas cell.

    Science.gov (United States)

    Hangauer, Andreas; Chen, Jia; Strzoda, Rainer; Amann, Markus-Christian

    2012-04-01

    For paramagnetic gases (e.g., O2, NO, NO2, OH) Zeeman modulation spectrometry is a method for spectrometric gas sensing with extraordinary selectivity. In this Letter it is combined with a hollow capillary based gas cell, where the gas is filled in long light-guiding capillary that is placed inside a toroidal coil. Over conventional Zeeman spectrometry this has the advantage of lower power consumption at long optical path length, since several loops of the hollow capillary fiber can be placed in the coil. Compared to wavelength modulation spectrometry the advantage is insensitivity to interference by multimode propagation in the fiber and absorption by other nonparamagnetic gases, which should enhance both sensor stability and sensitivity. Experimental and theoretical results are presented, showing the feasibility of the approach.

  4. Electrochemically Active Polymeric Hollow Fibers based on Poly(ether- b -amide)/Carbon Nanotubes

    KAUST Repository

    Cuevas, Carolina

    2017-09-18

    A simple and effective method to incorporate catalytic activity to a hollow fiber membrane is reported. Polyetherimide hollow fiber membranes were coated with a solution containing carboxyl-functionalized multi-walled carbon nanotubes and poly(ether-b-amide). Electron microscopy images confirmed the presence of a layer of percolating carbon nanotubes on the surface of the membranes. Cyclic voltammetry and linear swept voltammetry experiments showed that these membranes are able to drive the reactions of hydrogen evolution, and oxygen reduction, making them a cheaper, and greener substitute for platinum based cathodes in microbial bioelectrochemical systems. Water flux and molecular weight cut off experiments indicated that the electrochemically active coating layer does not affect the ultrafiltration performance of the membrane.

  5. Hydrogenotrophic denitrification of highly saline aquaculture wastewater using hollow fiber membrane bioreactor.

    Science.gov (United States)

    Visvanathan, C; Phong, D D; Jegatheesan, V

    2008-06-01

    A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating and recycling synthetic aquaculture wastewater. Hollow fibers ensured bubble-less diffusion of hydrogen and subsequent removal of nitrate from the first bioreactor. The second aerobic reactor was used for biomass filtration and removal of organic matter. Nitrate and organic matter expressed as dissolved organic carbon were 50 mgl(-1) and 20 mgl(-1), respectively, in the inlet. Acclimatization of hydrogenotrophic bacteria to 10, 20 and 30 ppt of salinity was also observed. Optimum hydraulic retention time and denitrification rate corresponding to these salinities were 3, 5 and 6 h and 366.8, 226.2 and 193.2 gm(-3) day(-1), respectively.

  6. PVDF hollow fiber and nanofiber membranes for fresh water reclamation using membrane distillation

    KAUST Repository

    Francis, Lijo

    2013-11-26

    Polyvinylidene fluoride hollow fiber and nanofibrous membranes are engineered and successfully fabricated using dry-jet wet spinning and electrospinning techniques, respectively. Fabricated membranes are characterized for their morphology, average pore size, pore size distribution, nanofiber diameter distribution, thickness, and water contact angle. Direct contact membrane distillation (DCMD) performances of the fabricated membranes have been investigated using a locally designed and fabricated, fully automated MD bench scale unit and DCMD module. Electrospun nanofibrous membranes showed a water flux as high as 36 L m-2 h-1 whereas hollow fiber membranes showed a water flux of 31.6 L m-2 h-1, at a feed inlet temperature of 80 °C and at a permeate inlet temperature of 20 °C.

  7. Fiber Drawn 2D Polymeric Photonic Crystal THz Filters

    DEFF Research Database (Denmark)

    Stecher, Matthias; Jansen, Christian; Ahmadi-Boroujeni, Mehdi

    2012-01-01

    In this paper, we report on different polymeric 2D photonic crystal filters for THz frequencies which are fabricated by a standard fiber drawing technique. The bandstop filters were simulated and designed by the generalized multipole technique (GMT). The frequency and angle dependent transmission...

  8. Design and analysis of photonic quasi-crystal hollow core fibers

    Science.gov (United States)

    Bahrampour, Abolfazl; Iadicicco, Agostino; Bahrampour, Ali Reza; Campopiano, Stefania; Cutolo, Antonello; Cusano, Andrea

    2013-05-01

    We present a new class of hollow core photonic crystal fibers taking the advantages of quasi-crystals structures. We analyze two structures based on modified 8-fold and 12-fold symmetries and we presente the ability of air guiding propagation having two photonic bandgap in the λ/Λ<1 In this paper bandgap of both structures as well as the behavior of the guided modes via finite element method are investigated.

  9. UV resonance Raman sensing of pharmaceutical drugs in hollow fibers

    Science.gov (United States)

    Yan, D.; Popp, J.; Frosch, T.

    2014-05-01

    We report about the experimental combination of UV resonance Raman sensing (UV-RRS) and fiber enhanced Raman sensing (FERS) on pharmaceuticals. The results show that the chemical sensitivity is highly improved and at the same time the sample volume is reduced compared to conventional measurements. A hundreds-fold improvement of the limit of detection (LOD) has been achieved with the combination of resonance Raman enhancement and fiber enhancement. The enhanced Raman signal has a reliable linear relationship with the concentration of the analyte, and therefore shows great potential for quantitative analysis of pharmaceuticals.

  10. Glass fiber contamination of cigarette filters: an additional health risk to the smoker?

    Science.gov (United States)

    Pauly, J L; Lee, H J; Hurley, E L; Cummings, K M; Lesses, J D; Streck, R J

    1998-11-01

    We report here the results of studies documenting the contamination of a cigarette-appearing smoking article labeled Eclipse with glass fibers, fragments, and particles. Eclipse, a product of the R. J. Reynolds Tobacco Company (RJR), was commercialized in June of 1996. Eclipse is unlike conventional cigarettes in that, like its predecessor Premier, it is designed to heat and not burn tobacco. The purpose of Eclipse was to simplify the chemical composition and reduce the biological activity of the mainstream and sidestream smoke and to achieve a significant reduction of environmental tobacco smoke. In Eclipse, tobacco pyrolysis is reduced by a carbon fuel rod that serves as a heat source for generating an aerosol having nicotine and tobacco flavor. The carbon rod, at the tip of the cigarette, is insulated and bound with two wrapping mats of glass fibers. Recently, Eclipse has been modified to address consumer complaints of burdensome draw and off-taste. The redesigned Eclipse, which we have termed the NEW Eclipse, has an unconventional filter-appearing mouthpiece that consists of a cellulose acetate cylindrical bundle with a central hollow tunnel. In our analysis of Eclipse, glass fibers (length:width aspect ratio, > or = 3:1) were: (a) observed protruding from the tip; (b) identified on the white cigarette wrapping paper; (c) viewed on the surface of the cork-appearing tipping paper; (d) found in the pack residue; (e) discovered lying freely on the cut surface of the filter by both light and electron microscopy; (f) harvested from the filter with adhesive tape; and (g) displaced when Eclipse was smoked mechanically. In a study of Eclipse that had not been removed from carefully opened packs, we observed that > or = 95% of the filters were contaminated with glass fibers (Eclipse: Regular, n = 114/120, 95%; Milds, n = 118/120, 98%; Menthol, n = 120/120, 100%). Likewise, 99% of NEW Eclipse had glass fibers on the redesigned filter (Regular, n = 119/120). In contrast

  11. Bench Scale Thin Film Composite Hollow Fiber Membranes for Post-Combustion Carbon Dioxide Capture

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Paul [General Electric Global Research, Niskayuna, NY (United States); Bhandari, Dhaval [General Electric Global Research, Niskayuna, NY (United States); Narang, Kristi [General Electric Global Research, Niskayuna, NY (United States); McCloskey, Pat [General Electric Global Research, Niskayuna, NY (United States); Singh, Surinder [General Electric Global Research, Niskayuna, NY (United States); Ananthasayanam, Balajee [General Electric Global Research, Niskayuna, NY (United States); Howson, Paul [General Electric Global Research, Niskayuna, NY (United States); Lee, Julia [General Electric Global Research, Niskayuna, NY (United States); Wroczynski, Ron [General Electric Global Research, Niskayuna, NY (United States); Stewart, Frederick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Orme, Christopher [Idaho National Lab. (INL), Idaho Falls, ID (United States); Klaehn, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); McNally, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rownaghi, Ali [Georgia Inst. of Technology, Atlanta, GA (United States); Lu, Liu [Georgia Inst. of Technology, Atlanta, GA (United States); Koros, William [Georgia Inst. of Technology, Atlanta, GA (United States); Goizueta, Roberto [Georgia Inst. of Technology, Atlanta, GA (United States); Sethi, Vijay [Western Research Inst., Laramie, WY (United States)

    2015-04-01

    GE Global Research, Idaho National Laboratory (INL), Georgia Institute of Technology (Georgia Tech), and Western Research Institute (WRI) proposed to develop high performance thin film polymer composite hollow fiber membranes and advanced processes for economical post-combustion carbon dioxide (CO2) capture from pulverized coal flue gas at temperatures typical of existing flue gas cleanup processes. The project sought to develop and then optimize new gas separations membrane systems at the bench scale, including tuning the properties of a novel polyphosphazene polymer in a coating solution and fabricating highly engineered porous hollow fiber supports. The project also sought to define the processes needed to coat the fiber support to manufacture composite hollow fiber membranes with high performance, ultra-thin separation layers. Physical, chemical, and mechanical stability of the materials (individual and composite) towards coal flue gas components was considered via exposure and performance tests. Preliminary design, technoeconomic, and economic feasibility analyses were conducted to evaluate the overall performance and impact of the process on the cost of electricity (COE) for a coal-fired plant including capture technologies. At the onset of the project, Membranes based on coupling a novel selective material polyphosphazene with an engineered hollow fiber support was found to have the potential to capture greater than 90% of the CO2 in flue gas with less than 35% increase in COE, which would achieve the DOE-targeted performance criteria. While lab-scale results for the polyphosphazene materials were very promising, and the material was incorporated into hollow-fiber modules, difficulties were encountered relating to the performance of these membrane systems over time. Performance, as measured by both flux of and selectivity for CO2 over other flue gas constituents was found to deteriorate over time, suggesting a system that was

  12. Hollow Fibers Networked with Perovskite Nanoparticles for H2 Production from Heavy Oil

    Science.gov (United States)

    Jeon, Yukwon; Park, Dae-Hwan; Park, Joo-Il; Yoon, Seong-Ho; Mochida, Isao; Choy, Jin-Ho; Shul, Yong-Gun

    2013-10-01

    Design of catalytic materials has been highlighted to build ultraclean use of heavy oil including liquid-to-gas technology to directly convert heavy hydrocarbons into H2-rich gas fuels. If the H2 is produced from such heavy oil through high-active and durable catalysts in reforming process that is being constructed in hydrogen infrastructure, it will be addressed into renewable energy systems. Herein, the three different hollow fiber catalysts networked with perovskite nanoparticles, LaCr0.8Ru0.2O3, LaCr0.8Ru0.1Ni0.1O3, and LaCr0.8Ni0.2O3 were prepared by using activated carbon fiber as a sacrificial template for H2 production from heavy gas oil reforming. The most important findings were arrived at: (i) catalysts had hollow fibrous architectures with well-crystallized structures, (ii) hollow fibers had a high specific surface area with a particle size of ~50 nm, and (iii) the Ru substituted ones showed high efficiency for H2 production with substantial durability under high concentrations of S, N, and aromatic compounds.

  13. A simple sample preparation method for measuring amoxicillin in human plasma by hollow fiber centrifugal ultrafiltration.

    Science.gov (United States)

    Dong, Wei-Chong; Hou, Zi-Li; Jiang, Xin-Hui; Jiang, Ye

    2013-02-01

    A simple sample preparation method has been developed for the determination of amoxicillin in human plasma by hollow fiber centrifugal ultrafiltration (HF-CF-UF). A 400-μL plasma sample was placed directly into the HF-CF-UF device, which consisited of a slim glass tube and a U-shaped hollow fiber. After centrifugation at 1.25 × 10(3) g for 10 min, the filtrate was withdrawn from the hollow fiber and 20 µL was directly injected into the high-performance liquid chromatography (HPLC) for analysis. The calibration curve was linear over the range of 0.1-20 µg/mL (r = 0.9996) and the limit of detection was as low as 0.025 µg/mL. The average recovery and absolute recovery were 99.9% and 84.5%, respectively. Both the intra-day and inter-day precisions (relative standard deviation) were less than 3.1% for three concentrations (0.25, 2.5 and 10 µg/mL). The sample preparation process was simplified. Only after a single centrifugal ultrafiltration can the filtrate be injected directly into HPLC. The present method is simple, sensitive and accurate. It could be effective for the analysis of biological samples with high protein contents, especially for the biopharmaceutical analysis of drugs that use traditional isolation techniques for sample preparation such as the protein precipitation method.

  14. Green Modification of Outer Selective P84 Nanofiltration (NF) Hollow Fiber Membranes for Cadmium Removal

    KAUST Repository

    Gao, Jie

    2015-10-26

    Outer-selective thin-film composite (TFC) hollow fiber membranes are normally made from interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). However, the removal of excess MPD solution and the large consumption of alkane solvents are their technical bottlenecks. In this study, green methods to prepare the outer selective TFC hollow fiber membranes were explored by firstly modifying the membrane substrate with polyethyleneimine (PEI) and then by water soluble small molecules such as glutaraldehyde (GA) and epichlorohydrin (ECH). Using P84 polyimide as the substrate, not only do these modifications decrease substrate\\'s pore size, but also vary surface charge by making the membranes less positively charged. As a result, the resultant membranes have higher rejections against salts such as Na2SO4, NaCl and MgSO4. The PEI and then GA modified membrane has the best separation performance with a NaCl rejection over 90% and a pure water permeability (PWP) of 1.74±0.01 Lm−2bar−1h−1. It also shows an impressive rejection to CdCl2 (94%) during long-term stability tests. The CdCl2 rejection remains higher than 90% at operating temperatures from 5 to 60 °C. This study may provide useful insights for green manufacturing of outer-selective nanofiltration (NF) hollow fiber membranes.

  15. Design of robust hollow fiber membranes with high power density for osmotic energy production

    KAUST Repository

    Zhang, Sui

    2014-04-01

    This study highlights the design strategy of highly asymmetric hollow fiber membranes that possess both characteristics of high flux and high mechanical strength to effectively reap the osmotic energy from seawater brine with an ultrahigh power density. An advanced co-extrusion technology was employed to fabricate the polyethersulfone (PES) hollow fiber supports with diversified structures from macrovoid to sponge-like. The microstructure of the supports is found critical for the stability and water permeability of the thin film composite (TFC) membranes. A high porosity in the porous layer is needed to reduce internal concentration polarization, while a thick and relatively dense skin layer underneath the TFC layer is required to maintain good mechanical stability and stress dissipation. The pore size of the supporting layer underneath the TFC layer must be small with a narrow pore size distribution to ensure the formation of a less-defective, highly permeable and mechanically stable TFC layer. The newly developed hollow fiber comprising high asymmetry, high porosity, and a thick skin layer with a small and narrow pore size distribution underneath the TFC layer produces a maximum power density of 24.3W/m2 at 20.0bar by using 1M NaCl as the concentrated brine and deionized (DI) water as the feed. The proposed design strategy for ultrahigh power density membranes clearly advances the osmotic energy production close to commercialization with a quite cost-effective and practicable approach. © 2013 Elsevier B.V.

  16. Gas-Filled Hollow Core Fiber Lasers Based on Population Inversion

    Science.gov (United States)

    2013-12-05

    solid-core fiber laser systems. Gas- filled hollow-core fiber lasers based on population inversion from acetylene (12C2H2) and hydrogen cyanide (HCN...via first order rotational- vibrational overtones near 1.5 μm using 1-ns duration pulses from a home-built optical parametric amplifier. Narrow-band...laser emission peaks in the 3-μm region corresponding to the ΔJ = ±1 dipole allowed rotational transitions between the pumped vibrational overtone

  17. Identification of Bloch-modes in hollow-core Photonic Crystal Fiber cladding

    DEFF Research Database (Denmark)

    Couny, F.; Benabid, F.; Roberts, John

    2007-01-01

    length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives......We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field information is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short...

  18. Detailed study of macrobending effects in a wide transmission bandwidth hollow-core photonic bandgap fiber

    Science.gov (United States)

    Chen, Y.; Sandoghchi, S. R.; Numkam, E.; Bradley, T. D.; Hayes, J. R.; Wheeler, N. V.; Jasion, G.; Gray, D. R.; Poletti, F.; Petrovich, M. N.; Richardson, D. J.

    2016-04-01

    We study in detail the macrobending effects in a wide transmission bandwidth (~200nm) 19 cell hollow-core photonic bandgap fiber operating at 1550nm. Our results indicate low bend sensitivity over a ~130nm wide interval within the transmission window, with negligible loss (<0.1dB) for bending radii down to 5mm. The "red shift" and "blue shift" of the bandgap edge have been observed at the short and long wavelength edges, respectively. The cutoff wavelengths where air-guiding modes stop guiding can be extracted from the bending loss spectra, which matches well with the simulated effective refractive index map of such fiber.

  19. Resonant optical propulsion of a particle inside a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Maslov, A V

    2016-07-01

    Resonant propulsion of small nonresonant particles inside metal waveguides due to the formation of resonant states by the guided modes below their cutoffs has been predicted in the past. Here it is shown that stable resonant propulsion exists in hollow-core photonic crystal fibers, which are all-dielectric structures and are a major platform for various photonic applications. Specific features of the resonant propulsion are discussed together with the fiber design issues. The results may enable power-efficient transport of particles over long distances, particle sorting, and sensitive detection.

  20. High finesse hollow-core fiber resonating cavity for high sensitivity gas sensing application

    Science.gov (United States)

    Tan, Yanzhen; Jin, Wei; Yang, Fan; Ho, Hoi Lut

    2017-04-01

    We present all-fiber resonating Fabry-Perot gas cells made with a piece of hollow-core photonic bandgap fiber (HCPBF) sandwiched by two single mode fibers with mirrored ends. A HC-PBF cavity made of 6.75-cm-long HC-1550-06 fiber achieved a cavity finesse of 128, corresponding to an effective optical path length of 5.5 m. Such HC-PBF cavities can be used as absorption cells for high sensitivity gas detection with fast response. Preliminary experiment with a 9.4-cm-long resonating gas cell with a finesse of 68 demonstrated a detection limit better than 7.5 p.p.m. acetylene.

  1. Two-photon fluorescence microscope with a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Tai, Shih-Peng; Chan, Ming-Che; Tsai, Tsung-Han; Guol, Shi-Hao; Chen, Li-Jin; Sun, Chi-Kuang

    2004-12-13

    Self-phase-modulation and group velocity dispersion of near IR femtosecond pulses in fibers restrict their use in two-photon fluorescence microscopy (TPFM). Here we demonstrate a hollow-core photonic crystal fiber based two-photon fluorescence microscope with low nonlinearity and dispersion effects. We use this fiber-based TPFM system to take two-photon fluorescence (chlorophyll) images of mesophyll tissue in the leaf of Rhaphidophora aurea. With less than 2mW average power exposure on the leaf at 755nm, the near zero-dispersion wavelength, chloroplasts distribution inside the mesophyll cells can be identified with a sub-micron spatial resolution. The acquired image quality is comparable to that acquired by the conventional fiber-free TPFM system, due to the negligible temporal pulse broadening effect.

  2. Hollow-Core Photonic Crystal Fibers for Surface-Enhanced Raman Scattering Probes

    Directory of Open Access Journals (Sweden)

    Xuan Yang

    2011-01-01

    Full Text Available Photonic crystal fiber (PCF sensors based on surface-enhanced Raman scattering (SERS have become increasingly attractive in chemical and biological detections due to the molecular specificity, high sensitivity, and flexibility. In this paper, we review the development of PCF SERS sensors with emphasis on our recent work on SERS sensors utilizing hollow-core photonic crystal fibers (HCPCFs. Specifically, we discuss and compare various HCPCF SERS sensors, including the liquid-filled HCPCF and liquid-core photonic crystal fibers (LCPCFs. We experimentally demonstrate and theoretically analyze the high sensitivity of the HCPCF SERS sensors. Various molecules including Rhodamine B, Rhodamine 6G, human insulin, and tryptophan have been tested to show the excellent performance of these fiber sensors.

  3. Optical trapping and control of nanoparticles inside evacuated hollow core photonic crystal fibers

    Energy Technology Data Exchange (ETDEWEB)

    Grass, David, E-mail: david.grass@univie.ac.at; Fesel, Julian; Hofer, Sebastian G.; Kiesel, Nikolai; Aspelmeyer, Markus, E-mail: markus.aspelmeyer@univie.ac.at [Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, A-1090 Vienna (Austria)

    2016-05-30

    We demonstrate an optical conveyor belt for levitated nanoparticles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to some theoretical predictions, we find a linear pressure dependence inside the HCPCF, extending over three orders of magnitude from 0.2 mbar to 100 mbar. A targeted application is the controlled delivery of nanoparticles from ambient pressure into medium vacuum.

  4. Hollow core photonic bandgap fiber with microfluid-infiltrated air holes for slow-light propagation

    Science.gov (United States)

    Ren, Liyong; Liang, Jian; Yun, Maojin

    2012-10-01

    Slow light plays an important role in the fields of all-optical signal processing and integration photonics. It has shown many potential applications, such as realizing optical delay lines or buffers, enhancing linear and nonlinear light-matter interactions, as well as increasing the sensitivity of the interferometers and transducers. In this paper, hollow-core photonic bandgap fibers made from high index glasses are designed by infiltrating microfluid into the air-holes to tailor the fiber dispersion for slow-light propagation under low pulse distortion. In such a fiber made from Si material, group index ng~8 is obtained with a bandwidth up to 30 nm, where the group index fluctuation is restricted in ±10 % of the ng, while ng~6 is obtained with a bandwidth over 100 nm when the chalcogenide material is selected instead. Such a ±10 % criterion determines a regarded flatland region accordingly, and in this region the group velocity dispersion can be negligible. It is found that for the same fiber length the slow-light time delay in the photonic bandgap fiber is much larger as compared with that in the single mode fiber. This kind of photonic bandgap fiber may have many potential applications in short-distance fiber communications and delay lines.

  5. High-Temperature Performance and Multiscale Damage Mechanisms of Hollow Cellulose Fiber-Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Liping Guo

    2016-01-01

    Full Text Available Spalling resistance properties and their damage mechanisms under high temperatures are studied in hollow cellulose fiber-reinforced concrete (CFRC used in tunnel structures. Measurements of mass loss, relative dynamic elastic modulus, compressive strength, and splitting tensile strength of CFRC held under high temperatures (300, 600, 800, and 1050°C for periods of 2.5, 4, and 5.5 h were carried out. The damage mechanism was analyzed using scanning electron microscopy, mercury intrusion porosimetry, thermal analysis, and X-ray diffraction phase analysis. The results demonstrate that cellulose fiber can reduce the performance loss of concrete at high temperatures; the effect of holding time on the performance is more noticeable below 600°C. After exposure to high temperatures, the performance of ordinary concrete deteriorates faster and spalls at 700–800°C; in contrast, cellulose fiber melts at a higher temperature, leaving a series of channels in the matrix that facilitate the release of the steam pressure inside the CFRC. Hollow cellulose fibers can thereby slow the damage caused by internal stress and improve the spalling resistance of concrete under high temperatures.

  6. Characterization of Thermally Cross-Linkable Hollow Fiber Membranes for Natural Gas Separation

    KAUST Repository

    Chen, Chien-Chiang

    2013-01-23

    The performance of thermally cross-linkable hollow fiber membranes for CO2/CH4 separation and the membrane stability against CO2 plasticization was investigated. The fiber membranes were thermally cross-linked at various conditions. Cross-linking temperature was found to have a significant effect, while shorter soak time and the presence of trace oxidizer (O2 or N2O) had a negligible effect. The cross-linked fibers were tested using high CO2 content feeds (50-70% CO2) at a variety of feed pressures (up to 1000 psia), temperatures, and permeate pressures (up to 100 psia) to evaluate membrane performance under various realistic operating conditions. The results demonstrated that cross-linking improves membrane selectivity and effectively eliminates swelling-induced hydrocarbon loss at high pressures. Excellent stability under aggressive feeds (with CO2 partial pressure up to 700 psia) suggests that cross-linked hollow fiber membranes have great potential for use in diverse aggressive applications, even beyond the CO2/CH4 example explored in this work. © 2012 American Chemical Society.

  7. EFFECTS OF PRESSURE AND TEMPERATURE ON ULTRAFILTRATION HOLLOW FIBER MEMBRANE IN MOBILE WATER TREATMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    ROSDIANAH RAMLI

    2016-07-01

    Full Text Available In Sabah, Malaysia, there are still high probability of limited clean water access in rural area and disaster site. Few villages had been affected in Pitas due to improper road access, thus building a water treatment plant there might not be feasible. Recently, Kundasang area had been affected by earthquake that caused water disruption to its people due to the damage in the underground pipes and water tanks. It has been known that membrane technology brought ease in making mobile water treatment system that can be transported to rural or disaster area. In this study, hollow fiber membrane used in a mobile water treatment system due to compact and ease setup. Hollow fiber membrane was fabricated into small module at 15 and 30 fibers to suit the mobile water treatment system for potable water production of at least 80 L/day per operation. The effects of transmembrane pressure (TMP and feed water temperature were investigated. It was found that permeate flux increases by more than 96% for both 15 and 30 fiber bundles with increasing pressure in the range of 0.25 to 3.0 bar but dropped when the pressure reached maximum. Lower temperature of 17 to 18˚C increase the water viscosity by 15% from normal temperature of water at 24˚C, making the permeate flux decreases. The fabricated modules effectively removed 96% turbidity of the surface water sample tested.

  8. Fabrication and formation mechanism of poly (L-lactic acid ultrafine multi-porous hollow fiber by electrospinning

    Directory of Open Access Journals (Sweden)

    Q. Z. Yu

    2013-01-01

    Full Text Available Poly(L-lactic acid (PLLA ultrafine multi-porous hollow fibers are fabricated by electrospinning with methylene dichloride as solvent. The Kirkendall effect has been widely applied for the fabrication of hollow structure in metals and inorganic materials. In this study, a conceptual extension is proposed for the formation mechanism: the development of porous hollow fiber undergoes three stages. The initial stage is the generation of small voids or pits on the surface of the fiber via surface diffusion and phase separation; the second stage is the formation of multi-pores penetrating the core of the fiber through the interaction of Kirkendall effect, surface diffusion and phase separation; the third stage is dominated by surface diffusion of the core material along the pore surface. To explore the formation conditions, the factors including ambient temperature, relativity humidity (R. H., molecular weight and fiber diameter are studied. The longitudinal and cross sectional morphologies of these fibers are examined by scanning electron micrograph (SEM. The results show that the prerequisite for the formation of uniform porous hollow PLLA fibers include moderate ambient temperature (10~20°C and appropriate molecular weight for the PLLA, as well as the diameter of the fiber in the range of several micrometers to about 100 nanometers.

  9. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    DEFF Research Database (Denmark)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-01-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal...

  10. Outer-selective thin film composite (TFC) hollow fiber membranes for osmotic power generation

    KAUST Repository

    Le, Ngoc Lieu

    2016-01-14

    The pressure-retarded osmosis (PRO) process is a green technique for power generation to respond the world\\'s need of energy sustainability. In this study, we have developed the vital component of the process, i.e. membrane, in the configuration of the outer-selective thin-film composite (TFC) hollow fiber, which is more practical than other configurations in the real applications. The support layer morphology and the formation of the selective polyamide layer have been optimized for a good PRO performance. The results show that the bore fluid with higher amount of the solvent N-methyl-2-pyrrolidone leads to full finger-like hollow fibers, which provide higher flux but lower pressure tolerance. The addition of higher amount of diethylene glycol into the dope solution, improves the pore formation and suppresses the macrovoid formation, while properly lowering the take-up speed increases their wall thickness and pressure tolerance. A simple alcohol-pre-wetting approach on the fiber support leads to a smooth and thin polyamide layer, which is favorable for a high water flux and power density. Its efficiency follows this order: n-propanol>ethanol>methanol>water. The n-propanol pre-wetted TFC membrane can tolerate 17 bar with a peak power density of 9.59 W/m2 at room temperature, using 1 M NaCl solution as the draw solution and DI water as feed. This work demonstrates the potential of outer-selective TFC hollow fiber membranes for energy conversion via PRO process, provides useful database to fabricate suitable support morphology and raise a simple technique to practically form a thin and smooth polyamide layer.

  11. Fiber Bragg Grating Filter High Temperature Sensors

    Science.gov (United States)

    Lyons, Donald R.; Brass, Eric D.; Pencil, Eric (Technical Monitor)

    2001-01-01

    We present a scaled-down method for determining high temperatures using fiber-based Bragg gratings. Bragg gratings are distributed along the length of the optical fiber, and have high reflectivities whenever the optical wavelength is twice the grating spacing. These spatially distinct Bragg regions (located in the core of a fiber) are sensitive to local temperature changes. Since these fibers are silica-based they are easily affected by localized changes in temperature, which results in changes to both the grating spacing and the wavelength reflectivity. We exploit the shift in wavelength reflectivity to measure the change in the local temperature. Note that the Bragg region (sensing area) is some distance away from where the temperature is being measured. This is done so that we can measure temperatures that are much higher than the damage threshold of the fiber. We do this by affixing the fiber with the Bragg sensor to a material with a well-known coefficient of thermal expansion, and model the heat gradient from the region of interest to the actual sensor. The research described in this paper will culminate in a working device as well as be the second portion of a publication pending submission to Optics Letters.

  12. Medical Application of Free Electron Laser Trasmittance using Hollow Optical Fiber

    CERN Document Server

    Suzuki, Sachiko; Ishii, Katsonuri

    2004-01-01

    Mid-infrared Free Electron Laser (FEL) is expected as new application for biomedical surgery. However, delivery of MIR-FEL into the body is difficult because the common glass optical fibers have strong absorption at MIR region. A good operational and flexible line for FEL is required at medical field. A Hollow optical fiber is developed for IR laser and high-power laser delivery. We evaluated the fiber for FEL transmission line. This fiber is coated with cyclic olefin polymer (COP) and silver thin film on the inside of glass capillary tube. It is 700 μm-bore and 1m in lengths. The fiber transmission loss of the measured wavelength region of 5.5 μm to 12 μm is less than 1dB/m when the fiber is straight and 1.2 dB/m when bent to radius of 20 cm. Additionally, the output beam profile and the pulse structure is not so different form incidence beam. In conclusion, the fiber is suitable for delivery of the FEL energy for applications in medical and laser surgery.

  13. Three-phase hollow fiber microextraction based on two immiscible organic solvents for determination of tricyclic antidepressant drugs: comparison with conventional three-phase hollow fiber microextraction.

    Science.gov (United States)

    Ghambarian, Mahnaz; Yamini, Yadollah; Esrafili, Ali

    2012-01-27

    The aim of this research was to compare the extraction efficiencies of two modes of three-phase hollow fiber microextraction (HF-LLLME) based on aqueous and organic acceptor phases for analysis of tricyclic antidepressant (TCA) drugs. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) was applied for determination of the drugs. In order to examine the ability of the new concept of HF-LLLME based on organic acceptor solvent in comparison with aqueous acceptor phase to extract the analytes, four TCAs were selected. The effect of different extraction conditions (i.e., type of acceptor phase, hollow fiber length, ionic strength, stirring rate, and extraction time) on the extraction efficiency of the TCAs was investigated and optimized using central composite design (CCD) as a powerful tool. Both methods were characterized by good linearity and high repeatability, but HF-LLLME with organic acceptor provided higher extraction efficiency and thus lower limits of detection (LODs). Calibration curves were linear (r(2)>0.996) in the range of 0.2-200 μgL(-1). LODs for all the TCAs ranged from 0.08 to 0.2 μgL(-1) using HPLC-DAD. Also an improvement in sensitivity of several orders of magnitude was achieved using single-ion monitoring GC-MS analyses (0.04 μgL(-1)) due to compatibility of this technique with GC instrument. The applicability of the proposed HF-LLLME/GC-MS and HPLC-DAD methods was demonstrated by analyzing the drugs in spiked urine and plasma samples. The obtained recoveries of the drugs in the range of 87.9-109.2% indicated the excellent capability of the developed method for extraction of TCAs from complex matrices. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Design and fabrication of inner-selective thin-film composite (TFC) hollow fiber modules for pressure retarded osmosis (PRO)

    KAUST Repository

    Wan, Chun Feng

    2016-08-03

    Pressure retarded osmosis (PRO) is a promising technology to harvest the renewable osmotic energy from salinity gradients. There are great progresses in the fabrication of PRO membranes in the last decade. Thin-film composite (TFC) hollow fibers have been widely studied and demonstrated superior performance. However, the lack of effective TFC hollow fiber modules hinders the commercialization of the PRO technology. Knowledge and experiences to fabricate TFC hollow fiber modules remain limited in the open literature. In this study, we aim to reveal the engineering and science on how to fabricate TFC hollow fiber modules including the formation of inner-selective polyamide layers and the repair of leakages. TFC-PES hollow fiber modules with 30% and 50% packing densities have been successfully fabricated, showing peak power densities of 20.0 W/m2 and 19.4 W/m2, respectively, at 20 bar using 1 M NaCl solution and DI water as feeds. The modules may be damaged during handling and high pressure testing. The repaired modules have a power density of 18.2 W/m2, 91% of the power densities of the undamaged ones. This study would make up the gap between TFC membrane fabrication and TFC membrane module fabrication in the membrane industry. © 2016 Elsevier B.V.

  15. In-fiber Mach-Zehnder interferometer for gas refractive index measurements based on a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Andrews, Nicholas L P; Ross, Rachel; Munzke, Dorit; van Hoorn, Camiel; Brzezinski, Andrew; Barnes, Jack A; Reich, Oliver; Loock, Hans-Peter

    2016-06-27

    We describe an in-fiber interferometer based on a gas-filled hollow-core photonic crystal fiber. Expressions for the sensitivity, figure of merit and refractive index resolution are derived, and values are experimentally measured and theoretically validated using mode field calculations. The refractive indices of nine monoatomic and molecular gases are measured with a resolution of δns -6.

  16. A theoretical model for evaluation of the design of a hollow-fiber membrane oxygenator.

    Science.gov (United States)

    Tabesh, Hadi; Amoabediny, Ghassem; Poorkhalil, Ali; Khachab, Ali; Kashefi, Ali; Mottaghy, Khosrow

    2012-12-01

    Geometric data are fundamental to the design of a contactor. The efficiency of a membrane contactor is mainly defined by its mass-transfer coefficient. However, design modifications also have significant effects on the performance of membrane contactors. In a hollow-fiber membrane oxygenator (HFMO), properties such as priming volume and effective membrane surface area (referred to as design specifications) can be determined. In this study, an extensive theoretical model for calculation of geometric data and configuration properties, and, consequently, optimization of the design of an HFMO, is presented. Calculations were performed for Oxyphan(®) hollow-fiber micro-porous membranes, which are frequently used in current HFMOs because of their high gas exchange performance. The results reveal how to regulate both the transverse and longitudinal pitches of fiber bundles to obtain a lower rand width and a greater number of windings. Such modifications assist optimization of module design and, consequently, substantially increase the efficiency of an HFMO. On the basis of these considerations, three values, called efficiency factors, are proposed for evaluation of the design specifications of an HFMO with regard with its performance characteristics (i.e. oxygen-transfer rate and blood pressure drop). Moreover, the performance characteristics of six different commercial HFMOs were measured experimentally, in vitro, under the same standard conditions. Comparison of calculated efficiency factors reveals Quadrox(®) is the oxygenator with the most efficient design with regard with its performance among the oxygenators tested.

  17. Tri-bore PVDF hollow fibers with a super-hydrophobic coating for membrane distillation

    KAUST Repository

    Lu, Kang-Jia

    2016-04-26

    Membranes with good mechanical strength, high vapor flux and outstanding anti-wetting properties are essential for membrane distillation (MD) applications. In this work, porous polyvinylidene fluoride (PVDF) tri-bore hollow fiber membranes with super-hydrophobicity are developed to achieve these desired properties. The tri-bore hollow fiber offers better mechanical strength than the conventional single-bore fiber. To improve its anti-wetting properties, Teflon® AF 2400 is coated on the membrane surface. The effects of coating on membrane morphology, performance and anti-wetting properties have been thoroughly investigated. With an optimal coating condition (0.025 wt% of Teflon® AF 2400, 30 s), a super-hydrophobic surface with a contact angle of 151o is achieved. The resultant membrane shows an increase of 109% in liquid entry pressure (LEP) with a slight sacrifice of 21% in flux. Long term direct contact MD tests have confirmed that the Teflon® AF 2400 coated membrane has enhanced stability with an average flux of 21 kg m-2 h-1 and rejection of 99.99% at 60 °° C for desalination application.

  18. Preparation and performance of biofouling resistant PAN/chitosan hollow fiber membranes.

    Science.gov (United States)

    Shanthana Lakshmi, D; Jaiswar, Santlal; Saxena, Mayank; Tasselli, Franco; Raval, Hiren D

    2017-07-01

    The preparation of polyacrylonitrile (PAN) hollow fiber (HF) membranes has been carried out by dry-jet wet spinning. PAN HF membranes were coated with chitosan biopolymers 2 wt% by dip coating and further crosslinked by chemical reagents (Tri sodium polyphosphate). PAN HF (Virgin) and PAN/chitosan coated membrane were characterized by SEM and tested for water flux. Proteins Pepsin, Albumin, and Clay of 1000 ppm concentration were tested for separation efficiency. In addition, bacterial species Escherichia coli and Bacillus subtilis were tested for fouling control efficiency and found out that PAN/chitosan membranes were quite superior to virgin PAN fibers. The adhesion of bacterial cells on the surface of the hollow fiber membranes assessed through alcian blue staining and SEM analysis. It was observed that PAN/chitosan membranes (310A and 310C) possessed best antibacterial activities (based on SEM results), qualifying them as a very promising candidates for anti-biofouling coatings.

  19. Effect of Spinneret Dimension on Structure and Performance of Polyetherimide Hollow Fiber Membrane in Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Gholamreza Bakeri

    2017-09-01

    Full Text Available In hollow fiber membrane fabrication process, a number of parameters such as dope compositions and flow rate, bore fluid type and flow rate, air gap etc. affect on the structure and characteristics of membrane. One of effective parameters is the dimension of spinneret and in this study; the effects of this parameter on the properties of polyetherimide (PEI hollow fiber membrane and its performance in membrane contactor were studied. A polymer solution was used for fabrication of two PEI membranes at the same fabrication conditions while the dimension of spinneret was different. Through the addition of water as the nonsolvent additive to the polymer solution, the thermodynamic stability of the solution decreased and upon the enhancement in the phase inversion process, the effects of chain reorientation or chain relaxation on the structure of hollow fiber membrane were minimized. The fabricated membranes were characterized by different tests and their performance in membrane contractor and in CO2 absorption test was evaluated in two cases: 1- distilled water in lumen side and pure CO2 in shell side, 2- distilled water in shell side and pure CO2 in lumen side. The results show that smaller dimension of spinneret enhances the properties of membrane such as 250% increase in mean pore size and 300% increase in gas permeation rate. In addition, the smaller dimension of the spinneret makes more pores in the structure of membrane that can be related to the shorter diffusion length of the coagulant. Furthermore, the CO2 absorption flux improves by 150%.

  20. Supramolecular solvent-based hollow fiber liquid phase microextraction of benzodiazepines.

    Science.gov (United States)

    Rezaei, Fatemeh; Yamini, Yadollah; Moradi, Morteza; Daraei, Bahram

    2013-12-04

    A new, efficient, and environmental friendly hollow fiber liquid phase microextraction (HF-LPME) method based on supramolecular solvents was developed for extraction of five benzodiazepine drugs. The supramolecular solvent was produced from coacervation of decanoic acid aqueous vesicles in the presence of tetrabutylammonium (Bu4N(+)). In this work, benzodiazepines were extracted from aqueous samples into a supramolecular solvent impregnated in the wall pores and also filled inside the porous polypropylene hollow fiber membrane. The driving forces for the extraction were hydrophobic, hydrogen bonding, and π-cation interactions between the analytes and the vesicular aggregates. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) was applied for separation and determination of the drugs. Several parameters affecting the extraction efficiency including pH, hollow fiber length, ionic strength, stirring rate, and extraction time were investigated and optimized. Under the optimal conditions, the preconcentration factors were obtained in the range of 112-198. Linearity of the method was determined to be in the range of 1.0-200.0 μg L(-1) for diazepam and 2.0-200.0 μg L(-1) for other analytes with coefficient of determination (R(2)) ranging from 0.9954 to 0.9993. The limits of detection for the target benzodiazepines were in the range of 0.5-0.7 μg L(-1). The method was successfully applied for extraction and determination of the drugs in water, fruit juice, plasma and urine samples and relative recoveries of the compounds studied were in the range of 90.0-98.8%. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Hollow Fibers Networked with Perovskite Nanoparticles for H2 Production from Heavy Oil

    OpenAIRE

    Jeon, Yukwon; Park, Dae-Hwan; Park, Joo-Il; Yoon, Seong-Ho; Mochida, Isao; Choy, Jin-Ho; Shul, Yong-Gun

    2013-01-01

    Design of catalytic materials has been highlighted to build ultraclean use of heavy oil including liquid-to-gas technology to directly convert heavy hydrocarbons into H2?rich gas fuels. If the H2 is produced from such heavy oil through high-active and durable catalysts in reforming process that is being constructed in hydrogen infrastructure, it will be addressed into renewable energy systems. Herein, the three different hollow fiber catalysts networked with perovskite nanoparticles, LaCr0.8R...

  2. Soliton-plasma nonlinear dynamics in mid-IR gas-filled hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Selim; Markos, Christos; Bang, Ole

    2017-01-01

    We investigate numerically soliton-plasma interaction in a noble-gas-filled silica hollow-core anti-resonant fiber pumped in the mid-IR at 3.0 mu m. We observe multiple soliton self-compression stages due to distinct stages where either the self-focusing or the self-defocusing nonlinearity...... by supercontinuum generation spanning 1-4 mu m. We find that the spectral coherence drops as the secondary compression stage is initiated. (C) 2017 Optical Society of America...

  3. A simulation model for transient response of a gas separation module using a hollow fiber membrane

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Takahiko, E-mail: t-sugiyama@nucl.nagoya-u.ac.jp [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Miyahara, Naoya [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, Masahiro [National Institute for Fusion Science, Oroshi-cho 322-6, Toki 509-5292 (Japan); Munakata, Kenzo [Akita University, Tegata Gakuen-cho 1-1, Akita-shi, Akita 010-8502 (Japan); Yamamoto, Ichiro [Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2011-10-15

    A simulation model has been developed for transient response of a gas separation module using a hollow fiber membrane for the removal of tritium from the atmosphere of the confinement space. The mass transfer process such as sorption and desorption of gases at the surface of the dense layer and the porous support layer, diffusive transfer in the both layers are treated in the model. Sorption isotherm, mass transfer rate and permeance are estimated through step-wise transient response experiments. The present model represents well not only separation factors and recovery ratio at the steady state but also responses to the multi-step wise change in the sweep gas rate.

  4. Interference-based optical measurement of fluidic flow in a hollow-core fiber

    Science.gov (United States)

    Lee, Min-Hwan; Kim, Sung-Hyun; Kim, Eun-Sun; Hwang, In-Kag

    2017-11-01

    In this study, we present speed and displacement measurements of micro-fluid in a hollow-core optical fiber, where an optical interference signal is created by two guided beams reflected at a fixed facet and a moving fluid end. By counting the number of intensity oscillations of the signal, the movement of the fluid end is successfully traced with high accuracy. Furthermore, we could detect the change in curvature diameters of the fluid end depending on the flow direction by monitoring the visibility of the interference signal.

  5. Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Scolari, Lara; Weirich, Johannes

    2008-01-01

    A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at X=1364nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed...... by increasing the temperature from 25°C to 100°C. The measurements are compared to a simulated spectrum obtained by means of a vectorial Beam Propagation Method model....

  6. Darcy permeability of hollow fiber membrane bundles made from Membrana® Polymethylpentene (PMP) fibers used in respiratory assist devices

    Science.gov (United States)

    Madhani, Shalv. P.; D’Aloiso, Brandon. D.; Frankowski, Brian.; Federspiel, William. J.

    2016-01-01

    Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake – Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana® polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A=497ε-103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to −3.5% of our prior correlation over the tested porosity range. PMID:26809086

  7. Darcy Permeability of Hollow Fiber Membrane Bundles Made from Membrana Polymethylpentene Fibers Used in Respiratory Assist Devices.

    Science.gov (United States)

    Madhani, Shalv P; D'Aloiso, Brandon D; Frankowski, Brian; Federspiel, William J

    2016-01-01

    Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake-Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular, and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A = 497ε - 103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to -3.5% of our prior correlation over the tested porosity range.

  8. Poly(ethyleneimine) infused and functionalized Torlon®-silica hollow fiber sorbents for post-combustion CO2 capture

    KAUST Repository

    Li, Fuyue Stephanie

    2014-03-01

    Organic-inorganic hybrid materials functionalized with amine-containing reagents are emerging as an important class of materials for capturing carbon dioxide from flue gas. Polymeric silica hollow fiber sorbents are fabricated through the proven dry-jet/wet-quench spinning process. In our study, a new technique for functionalizing polymeric silica hollow fiber sorbents with poly(ethyleneimine), followed by a post-spinning infusion step was studied. This two step process introduces a sufficient amount of poly(ethyleneimine) to the polymeric silica hybrid material support to improve the CO2 sorption capacity due to the added amine groups. The poly(ethyleneimine) infused and functionalized hollow fiber sorbents are also characterized by a thermal gravimetric analyzer (TGA) to assess their CO2 sorption capacities. © 2014 Elsevier Ltd. All rights reserved.

  9. Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

    Science.gov (United States)

    Lunn, Griffin; Wheeler, Raymond; Hummerick, Mary; Birmele, Michele; Richards, Jeffrey; Coutts, Janelle; Koss, Lawrence; Spencer, Lashelle.; Johnsey, Marissa; Ellis, Ronald

    Bioreactor research, even today, is mostly limited to continuous stirred-tank reactors (CSTRs). These are not an option for microgravity applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. This has led to testing of Hollow Fiber Membrane Bioreactors (HFMBs) for microgravity applications, including possible use for wastewater treatment systems for the International Space Station (ISS). Bioreactors and filtration systems for treating wastewater could avoid the need for harsh pretreatment chemicals and improve overall water recovery. However, the construction of these reactors is difficult and commercial off-the-shelf (COTS) versions do not exist in small sizes. We have used 1-L modular HFMBs in the past, but the need to perform rapid testing has led us to consider even smaller systems. To address this, we designed and built 125-mL, rectangular reactors, which we have called the Fiber Attachment Module Experiment (FAME) system. A polycarbonate rack of four square modules was developed with each module containing removable hollow fibers. Each FAME reactor is self-contained and can be easily plumbed with peristaltic and syringe pumps for continuous recycling of fluids and feeding, as well as fitted with sensors for monitoring pH, dissolved oxygen, and gas measurements similar to their larger counterparts. The first application tested in the FAME racks allowed analysis of over a dozen fiber surface treatments and three inoculation sources to achieve rapid reactor startup and biofilm attachment (based on carbon oxidation and nitrification of wastewater). With these miniature FAME reactors, data for this multi-factorial test were collected in duplicate over a six-month period; this greatly compressed time period required for gathering data needed to study and improve bioreactor performance.

  10. Removing Pathogens Using Nano-Ceramic-Fiber Filters

    Science.gov (United States)

    Tepper, Frederick; Kaledin, Leonid

    2005-01-01

    A nano-aluminum-oxide fiber of only 2 nanometers in diameter was used to develop a ceramic-fiber filter. The fibers are electropositive and, when formulated into a filter material (NanoCeram(TradeMark)), would attract electro-negative particles such as bacteria and viruses. The ability to detect and then remove viruses as well as bacteria is of concern in space cabins since they may be carried onboard by space crews. Moreover, an improved filter was desired that would polish the effluent from condensed moisture and wastewater, producing potable drinking water. A laboratory- size filter was developed that was capable of removing greater than 99.9999 percent of bacteria and virus. Such a removal was achieved at flow rates hundreds of times greater than those through ultraporous membranes that remove particles by sieving. Because the pore size of the new filter was rather large as compared to ultraporous membranes, it was found to be more resistant to clogging. Additionally, a full-size cartridge is being developed that is capable of serving a full space crew. During this ongoing effort, research demonstrated that the filter media was a very efficient adsorbent for DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and endotoxins. Since the adsorption is based on the charge of the macromolecules, there is also a potential for separating proteins and other particulates on the basis of their charge differences. The separation of specific proteins is a major new thrust of biotechnology. The principal application of NanoCeram filters is based on their ability to remove viruses from water. The removal of more than 99.9999 percent of viruses was achieved by a NanoCeram polishing filter added to the effluent of an existing filtration device. NanoCeram is commercially available in laboratory-size filter discs and in the form of a syringe filter. The unique characteristic of the filter can be demonstrated by its ability to remove particulate dyes such as Metanyl yellow. Its

  11. Cross-correlated imaging of distributed mode filtering rod fiber

    DEFF Research Database (Denmark)

    Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

    2013-01-01

    We analyze the modal properties of an 85μm core distributed mode filtering rod fiber using cross-correlated (C2) imaging. We evaluate suppression of higher-order modes (HOMs) under severely misaligned mode excitation and identify a single-mode regime where HOMs are suppressed by more than 20dB....

  12. Thermal behaviors of stainless steel tube based GeO2 ATR hollow fibers for transmitting CO2 laser radiations

    Science.gov (United States)

    Wang, Xu; Wang, Lin; Fu, Xiaohong; Jing, Chengbin; Yue, Fangyu; Yang, Pingxiong; Chu, Junhao

    2017-10-01

    The stainless steel (SUS) capillary tube attenuated total reflective (ATR) GeO2 hollow waveguide has advantages of low fabrication cost, strong mechanic strength and low transmission loss. It can find laser power delivery applications such as laser surgery, and material processing. However, the temperature rise of the operating waveguide may affect the laser delivery stability and the laser surgery safety. The thermal behaviors of the SUS ATR hollow fiber transmitting CO2 laser were investigated theoretically and experimentally in this work. Both theoretic simulations and experimental results disclose the periodic oscillatory behavior of the fiber temperature. The influence of input laser power on fiber temperature has been quantitatively discussed. A maximum input laser power of 23 W is predicted for laser surgery in which case the fiber temperature had better be lower than 47 °C to avoid tissue scalds. An input laser power smaller than 137 W is suggested preventing the fiber from being overheated (150 °C).

  13. Analysis of polarization noise in transmissive single-beam-splitter resonator optic gyro based on hollow-core photonic-crystal fiber.

    Science.gov (United States)

    Jiao, Hongchen; Feng, Lishuang; Wang, Kai; Liu, Ning; Yang, Zhaohua

    2017-10-30

    We realize a transmissive single-beam-splitter resonator optic gyro based on a hollow-core photonic-crystal fiber (HCPCF), utilizing a micro-optical coupler formed by pairs of lenses and one filter, which is a new type of resonator fiber optic gyro based on the HCPCF (HC-RFOG). We build a mathematical model of the polarization noise based on the transfer function of this novel transmissive single-beam-splitter resonator. We construct a HC-RFOG and simulate and validate the effects of polarization noise on the gyro system. In addition, we apply an effective method to suppress the polarization noise and prove its efficacy through experiments. The bias stability of the gyro system is successfully improved from 25 °/h to 2 °/h, which indicates a remarkable advance of performance of HC-RFOG.

  14. 1-m tunable optical delay line using microfluid sliding in a hollow-core fiber: Feasibility study

    Science.gov (United States)

    Lee, Min-Hwan; Kim, Sung-Hyun; Kim, Eun-Sun; Hwang, In-Kag

    2017-11-01

    A novel variable optical delay line based on a hollow-core photonic bandgap fiber is proposed. The device incorporates microfluid, the end surface of which serves as an optical reflector, in the hollow-core of the fiber. The position of the fluid end is controlled by a syringe pump to change the optical delay of the reflected beam. We demonstrate wide tunability of the optical delay up to 1 m with a scan speed of several mm/s. The return loss and beat pattern in the reflected signal is studied and the potential of the device as an ultra-long delay line is discussed.

  15. Oxygen Transfer Model for a Flow-Through Hollow-Fiber Membrane Biofilm Reactor

    DEFF Research Database (Denmark)

    Gilmore, K. R.; Little, J. C.; Smets, Barth F.

    2009-01-01

    A mechanistic oxygen transfer model was developed and applied to a flow-through hollow-fiber membrane-aerated biofilm reactor. Model results are compared to conventional clean water test results as well as performance data obtained when an actively nitrifying biofilm was present on the fibers......-liquid interface was the most accurate of the predictive models (overpredicted by a factor of 1.1) while a coefficient determined by measuring bulk liquid dissolved oxygen underpredicted the oxygen transfer by a factor of 3. The mechanistic model was found to be an adequate tool for design because it used....... With the biofilm present, oxygen transfer efficiencies between 30 and 55% were calculated from the measured data including the outlet gas oxygen concentration, ammonia consumption stoichiometry, and oxidized nitrogen production stoichiometry, all of which were in reasonable agreement. The mechanistic model...

  16. A Pilot-Scale System for Carbon Molecular Sieve Hollow Fiber Membrane Manufacturing

    KAUST Repository

    Karvan, O.

    2012-12-21

    Carbon molecular sieve (CMS) membranes offer advantages over traditional polymeric membrane materials, but scale-up of manufacturing systems has not received much attention. In the recent decade, there has been a dramatic increase in fundamental research on these materials with a variety of applications being studied. The results from a pilot-scale CMS production system are presented. This system was designed based on extensive laboratory research, and hollow fiber membranes produced in this system show similar performance compared to membranes produced using a smaller bench-scale system. After optimizing the system design, a 93% recovery of the precursor fibers for use in membrane module preparation were obtained. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Mode-based microparticle conveyor belt in air-filled hollow-core photonic crystal fiber.

    Science.gov (United States)

    Schmidt, Oliver A; Euser, Tijmen G; Russell, Philip St J

    2013-12-02

    We show how microparticles can be moved over long distances and precisely positioned in a low-loss air-filled hollow-core photonic crystal fiber using a coherent superposition of two co-propagating spatial modes, balanced by a backward-propagating fundamental mode. This creates a series of trapping positions spaced by half the beat-length between the forward-propagating modes (typically a fraction of a millimeter). The system allows a trapped microparticle to be moved along the fiber by continuously tuning the relative phase between the two forward-propagating modes. This mode-based optical conveyor belt combines long-range transport of microparticles with a positional accuracy of 1 µm. The technique also has potential uses in waveguide-based optofluidic systems.

  18. Determination of volatile organic compounds in water using headspace knotted hollow fiber microextraction.

    Science.gov (United States)

    Chen, Pai-Shan; Tseng, Yu-Hsiang; Chuang, Yuh-Lin; Chen, Jung-Hsuan

    2015-05-22

    An efficient and effective headspace microextraction technique named static headspace knotted hollow fiber microextraction (HS-K-HFME) has been developed for the determination of volatile organic compounds (VOCs) in water samples. The knot-shaped hollow fiber is filled with 25μL of the extraction solvent. The excess solvent forms a large droplet (13μL) and is held in the center of the knot. Even after 20min of extraction time at high temperature (95°C) without cooling, there was still enough volume of extraction solvent for gas chromatography-mass spectrometry (GC-MS) analysis, which extends the choice of solvents for headspace LPME. Moreover, the knot-shaped fiber has a larger extraction contact interface, which increases the rate of mass transfer between the headspace and extraction solvent film attached to the fiber, thus improving the extraction efficiency. The effects of extraction solvent, temperature, stirring rate, salt concentration and extraction time on extraction performance were optimized. The calibration curves exhibited coefficients of determination (R(2)) ranging from 0.9957 to 0.9999 and the limit of detection (LOD) ranged from 0.2 to 10μgL(-1). Relative standard deviations (RSDs) ranged from 4.5% to 11.6% for intraday measurements (n=5). Interday (n=15) values were between 2.2% and 12.9%. The relative recoveries (RRs) ranged from 90.3% to 106.0% for river water and 95.9% to 103.6% for wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Liposome preparation using a hollow fiber membrane contactor--application to spironolactone encapsulation.

    Science.gov (United States)

    Laouini, A; Jaafar-Maalej, C; Sfar, S; Charcosset, C; Fessi, H

    2011-08-30

    In this study, we present a novel liposome preparation technique suitable for the entrapment of pharmaceutical and cosmetic agents. This new method uses a membrane contactor in a hollow fiber configuration. In order to investigate the process, key parameters influence on the liposome characteristics was studied. It has been established that the vesicle size distribution decreased with the organic phase pressure decrease, the phospholipid concentration decreases and the aqueous to organic phase volume ratio increases. Liposomes were filled with a hydrophobic drug model, spironolactone that could be used for a paediatric medication. The mean size of drug-free and drug-loaded liposomes was, respectively, 113 ± 4 nm and 123 ± 3 nm. The zeta potential of drug-free and drug-loaded liposomes was, respectively, -43 ± 0.7 mV and -23 ± 0.6 mV. High entrapment efficiency values were successfully achieved (93 ± 1.12%). Transmission electron microscopy images revealed nanometric sized and spherical shaped oligo-lamellar vesicles. The release profile showed a rapid and complete release within about 5h. Additionally, special attention was paid on process reproducibility and long term lipid vesicles stability. Results confirmed the robustness of the hollow fiber module based technique. Moreover, the technique is simple, fast and has a potential for continuous production of nanosized liposome suspensions at large scale. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Surface Plasmon Resonance Sensor Based on Ethylene Tetra-Fluoro-Ethylene Hollow Fiber

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-11-01

    Full Text Available A new kind of hollow fiber surface plasmon resonance sensor (HF-SPRS based on the silver-coated ethylene tetra-fluoro-ethylene (ETFE hollow fiber (HF is presented. The ETFE HF-SPRS is fabricated, and its performance is investigated experimentally by measuring the transmission spectra of the sensor when filled by liquid sensed media with different refractive indices (RIs. Theoretical analysis based on the ray transmission model is also taken to evaluate the sensor. Because the RI of ETFE is much lower than that of fused silica (FSG, the ETFE HF-SPRS can extend the lower limit of the detection range of the early reported FSG HF-SPRS from 1.5 to 1.42 approximately. This could greatly enhance the application potential of HF-SPRS. Moreover, the joint use of both ETFE and FSG HF-SPRSs can cover a wide detection range from 1.42 to 1.69 approximately with high sensitivities larger than 1000 nm/RIU.

  1. Amino-functionalized surface modification of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes

    Science.gov (United States)

    Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2017-08-01

    This study aimed to improve surface polarity of polydimethylsiloxane (PDMS) membranes and provide surface active sites which were easy to react with other chemicals. 3-Aminopropyltriethoxysilane (APTES) containing an amino group was introduced into a PDMS membrane by crosslinking to prepare polyacrylonitrile hollow fiber-supported PDMS membranes with an amino-functionalized surface. Fourier transform infrared and X-ray photoelectron spectroscopic analyses proved the existence of APTES and its amino group in the PDMS membrane. The concentration of N atoms on the PDMS membrane surface reached ∼6% when the mass ratio of APTES/PDMS oligomer in the PDMS coating solution was increased to 4/3. The water contact angle decreased from ∼114° to ∼87.5°, indicating the improved surface polarization of the PDMS membrane. The density and swelling degree of the PDMS membrane decreased and increased, respectively, with increasing APTES content in PDMS. This phenomenon increased CO2 permeability and decreased CO2/H2 selectivity, CO2/CH4 selectivity, and CO2/N2 selectivity. When the mass ratio of APTES/PDMS oligomer was increased from 0 to 4/3, the CO2 permeation rate of the hollow fiber-supported PDMS membranes initially decreased from ∼2370 GPU to ∼860 GPU and then increased to ∼2000 GPU due to the change in coating solution viscosity.

  2. [Recovery of zinc ion and cadmium ion with hollow fiber membrane extraction].

    Science.gov (United States)

    Wang, Y; Luo, G; Wang, Y; Wu, Z; Dai, Y

    2001-09-01

    The efficiency of hollow fiber membrane solvent extraction for the system of Meaq/bis(2-ethylhexyl) phosphate in heptane(Me = Cd2+, Zn2+) was studied for wastewater treatment and hydrometallurgy. It was found that the two phases velocity, the initial concentration and the pH value of the aqueous phase greatly influenced the extraction ratio. For very dilute solution with concentration lower than 500 mg/L, the mass transfer resistance was mainly in aqueous phase. When the aqueous phase concentration was relative higher than that of dilute solution, all the individual mass transfer resistances would not be ignored. For the concentrated solution, the mass transfer in the organic phase and the diffusion in membrane pores controlled the transport process. In the back extraction, the mass transfer resistance lied in the organic phase and the diffusion in membrane pores. The experimental results showed that it was possible that the extraction percentage achieved 90% when the metal ion concentration was lower than 400 mg/L. When the cadmium concentration was lower than 200 mg/L, its concentration can decrease 2 orders by extraction in a single-pass flow mode. The values of (HTU)w were between 15 cm and 30 cm, which was much lower than those of traditional extraction columns. The results indicated that membrane extraction with hollow fiber modules could efficiently remove or recover metal ions in the aqueous phases.

  3. Numerical Study on Flow Characteristics of Hollow Fiber Membrane Module for Water Recovery Cooling Tower

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Cheol; Shin, Weon Gyu [Chungnam Nat’l Univ., Daejeon (Korea, Republic of); Park, Hyun Seol; Lee, Hyung Keun [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2017-08-15

    The purpose of this study is to analyze the flow characteristics when a staggered hollow fiber membrane module is modeled as a porous medium. The pressure-velocity equation was used for modeling the porous medium, using pressure drop data. In terms of flow characteristics, we compared the case of the 'porous medium' when the membrane module was modeled as a porous medium with the case of the 'membrane module' when considering the original shape of the membrane module. The difference in pressure drop between the 'porous medium' and 'membrane module' was less than 0.6%. However, the maximum flow velocity and mean turbulent kinetic energy of the 'porous medium' were 2.5 and 95 times larger than those of the 'membrane module,' respectively. Our results indicate that modeling the hollow fiber module as a porous medium is useful for predicting pressure drop, but not sufficient for predicting the maximum flow velocity and mean turbulent kinetic energy.

  4. Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

    KAUST Repository

    Bettahalli Narasimha, Murthy Srivatsa

    2016-04-26

    Dehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

  5. Polyoxadiazole hollow fibers for produced water treatment by direct contact membrane distillation

    KAUST Repository

    Xu, Jingli

    2018-01-08

    Treatment of produced water in the petroleum industry has been a challenge worldwide. In this study, we evaluated the use of direct contact membrane distillation (DCMD) for this purpose, removing oil and dissolved elements and supplying clean water from waste. We synthesized fluorinated polyoxadiazole, a highly hydrophobic polymer, to fabricate hollow fiber membranes, which were optimized and tested for simulated produced water and real produced water treatment. The process performance was investigated under different operating parameters, such as feed temperature, feed flow velocity and length of the membrane module for 4 days. The results indicate that by increasing feed temperature and feed flow rate the vapor flux increases. The flux decreased with increasing the length of the module due to the decrease of the driving force along the module. The fouling behavior, which corresponds to flux decline and cleaning efficiency of the membrane, was studied. The performance of the fabricated hollow fiber membranes was demonstrated for the treatment of produced water, complying with the industrial reuse and discharge limits.

  6. The Performance and Fouling Control of Submerged Hollow Fiber (HF Systems: A Review

    Directory of Open Access Journals (Sweden)

    Ebrahim Akhondi

    2017-07-01

    Full Text Available The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF and ultrafiltration (UF applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO, and membrane bioreactors (MBRs. Compared to submerged flat sheet (FS membranes, submerged hollow fiber (HF membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

  7. Sensitivity enhanced fiber sensor based on a fiber ring microwave photonic filter with the Vernier effect.

    Science.gov (United States)

    Xu, Zuowei; Shu, Xuewen; Fu, Hongyan

    2017-09-04

    A temperature sensor employing the Vernier effect generated from a cascaded fiber rings based microwave photonic filter (MPF) is proposed and experimentally demonstrated. The structure of the fiber ring is used as a sensing element as well as the sampling and delaying component of the MPF in our proposed sensing scheme. The sensing characteristics of both single ring and cascaded fiber rings based sensors have been studied and compared. By employing two cascaded fiber rings of slightly different length, the Vernier effect can be generated in the frequency response of the MPF. The sensing interrogation of the cascaded fiber rings based sensor is conducted by detecting the frequency shift of the upper envelope of the measured frequency response curve. The experimental results show that the sensitivity of the cascaded fiber rings based sensor can be improved about 30 times compared with the single fiber ring based temperature sensor.

  8. Aminosilane-Functionalized Hollow Fiber Sorbents for Post-Combustion CO 2 Capture

    KAUST Repository

    Li, Fuyue Stephanie

    2013-07-03

    Increasing carbon dioxide emissions are generally believed to contribute to global warming. Developing new materials for capturing CO2 emitted from coal-fired plants can potentially mitigate the effect of these CO 2 emissions. In this study, we developed and optimized porous hollow fiber sorbents with both improved sorption capacities and rapid sorption kinetics by functionalizing aminosilane (N-(2-aminoethyl)-3- aminoisobutyldimethylmethoxysilane) to cellulose acetate hollow fibers as a "proof of concept". A lumen-side barrier layer was also developed in the aminosilane-functionalized cellulose acetate fiber sorbent to allow for facile heat exchange without significant mass transfer with the bore-side heat transfer fluid. The functionalized cellulose acetate fiber sorbents were characterized by pressure decay sorption measurements, multicomponent column chromatography, FT-IR, elemental analysis, and scanning electron microscopy. The carbon dioxide sorption capacity at 1 atm is 0.73 mmol/g by using the pressure decay apparatus. Multicomponent column chromatography measurements showed that aminosilane functionalized cellulose acetate fiber sorbent has a CO2 sorption capacity of 0.23 mmol/g at CO2 partial pressure 0.1 atm and 35 C in simulated flue gas. While this capacity is low, our proof of concept positions the technology to move forward to higher capacity with work that is underway. The presence of silicon and nitrogen elements in the elemental analysis confirmed the success of grafting along with FT-IR spectra which showed the absorbance peak (∼810 cm-1) for Si-C stretching. A cross-linked Neoprene material was used to form the lumen-side barrier layer. Preliminary data showed the required reduction in gas permeance to eliminate mixing between shell side and bore side fluid flows. Specifically the permeance was reduced from 10 000 GPUs for the neat fibers to 6.6 ± 0.1 and 3.3 ± 0.3 GPUs for the coated fibers. The selected lumen layer formation materials

  9. An alternative perspective of hollow fiber-mediated extraction: Bundled hollow fiber array-liquid-phase microextraction with sonication-assisted desorption and liquid chromatography-tandem mass spectrometry for determination of estrogens in aqueous matrices.

    Science.gov (United States)

    Goh, Shalene Xue Lin; Lee, Hian Kee

    2017-03-10

    A bundled hollow fiber array (BHF)-liquid-phase microextraction (LPME) approach has been developed for the ultra-high performance liquid chromatography tandem mass spectrometric determination of estrone, 17β-estradiol, estriol, and 17α-ethinylestradiol. The BHF was dipped in n-octanol to impregnate only the wall pores of the hollow fibers without deliberate loading of extractant solvent in the lumens, before placing it in the sample for extraction. Parameters influencing extraction efficiency, such as number of bundled hollow fibers, type of extraction and desorption solvent, agitation mode, extraction temperature and duration, and the salting out effect were examined. Under the most favourable experimental conditions, the enrichment factors were between 77 and 137-fold for the target compounds. The developed method offered high sensitivity and reproducibility. Low limits of detection and limits of quantification were achieved, i.e., between 0.251 and 0.440ng/L, and 0.995 and 1.82ng/L, respectively. Good intra and inter-day precision were obtained with relative standard deviations (RSDs) of less than 9%. BHF-LPME provided a new perspective on using membrane solvent-supported hollow fiber-mediated LPME. Raman spectroscopy was also introduced in this study to reaffirm that the polypropylene BHF did not play any role in the extraction; only the solvent was responsible. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Hybrid bioreactor (HBR) of hollow fiber microfilter membrane and cross-linked laccase aggregates eliminate aromatic pharmaceuticals in wastewaters.

    Science.gov (United States)

    Ba, Sidy; Jones, J Peter; Cabana, Hubert

    2014-09-15

    Widespread detection of numerous micropollutants including aromatic pharmaceuticals in effluents of wastewater treatment plants has prompted much research aimed at efficiently eliminating these contaminants of environmental concerns. In the present work, a novel hybrid bioreactor (HBR) of cross-linked enzymes aggregates of laccase (CLEA-Lac) and polysulfone hollow fiber MF membrane was developed for the elimination of acetaminophen (ACT), mefenamic acid (MFA) and carbamazepine (CBZ) as model aromatic pharmaceuticals. The MF alone showed removals of the three drugs varying approximately from 50 to 90% over the course of 8h in the filtrate of aqueous solution. Synergistic action of the MF and CLEA-Lac during operation achieved eliminations from aqueous solution of around 99%, nearly 100% and up to 85% for ACT, MFA and CBZ, respectively. Under continuous operation, the HBR demonstrated elimination rates of the drugs from filtered wastewater up to 93% after 72h for CBZ and near complete elimination of ACT and MFA was achieved within 24h of treatment. Concomitantly to the drugs eliminations in the wastewater, the CLEA-Lac exhibited 25% residual activity while being continuously recycled with no activity in the filtrate. Meanwhile, the filtrate flowrate showed only minor decline indicating limited fouling of the membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Collagenase-labile polyurethane urea synthesis and processing into hollow fiber membranes.

    Science.gov (United States)

    Fu, Hui-Li; Hong, Yi; Little, Steven R; Wagner, William R

    2014-08-11

    As a means to stimulate wound healing, a hollow fiber membrane system might be placed within a wound bed to provide local and externally regulated controlled delivery of regenerative factors. After sufficient healing, it would be desirable to triggerably degrade these fibers as opposed to pulling them out. Accordingly, a series of enzymatically degradable thermoplastic elastomers was developed as potential hollow fiber base material. Polyurethane ureas (PUUs) were synthesized based on 1, 4-diisocyanatobutane, polycaprolactone (PCL) diol and polyethylene glycol (PEG) at different molar fractions as soft segments, and collagenase-sensitive peptide GGGLGPAGGK-NH2 as a chain extender (defined as PUU-CLxEGy-peptide, where x and y are the respective molar percents). In these polymers, PEG in the polymer backbone decreased tensile strengths and initial moduli of solvent-cast films in the wet state, while increasing water absorption. Collagenase degradation was observed at 75% relative PEG content in the soft segment. Control PUUs with putrescine or nonsense peptide chain extenders did not degrade acutely in collagenase. Conduits electrospun from PUU-CL25EG75-peptide and PUU-CL50EG50-peptide exhibited appropriate mechanical strength and sustained release of a model protein from the tube lumen for 7 days. Collapse of PUU-CL25EG75-peptide tubes occurred after collagenase degradation for 3 days. In conclusion, through molecular design, synthesis and characterization, a collagenase-labile PUU-CL25EG75-peptide polymer was identified that exhibited the desired traits of triggerable lability, processability, and the capacity to act as a membrane to facilitate controlled protein release.

  12. Hollow fiber based quantum cascade laser spectrometer for fast and sensitive drug identification

    Science.gov (United States)

    Herbst, J.; Scherer, B.; Ruf, A.; Erb, J.; Lambrecht, A.

    2012-01-01

    Sensitive and fast identification of drugs or drug precursors is important and necessary in scenarios like baggage or container check by customs or police. Fraunhofer IPM is developing a laser spectrometer using external cavity quantum cascade lasers (EC-QCL) to obtain mid-infrared (IR) absorption spectra in the wavelength range of the specific vibrational bands of amphetamines and their precursors. The commercial EC-QCL covers a tuning range of about 225 cm-1 within 1.4 s. The system could be used for different sample types like bulk samples or liquid solutions. A sampling unit evaporates the sample. Because of small sample amounts a 3 m long hollow fiber with an inner volume smaller than 1ml is used as gas cell and wave guide for the laser beam. This setup is suitable as a detector of a gas chromatograph instead of a standard detector (TCD or FID). The advantage is the selective identification of drugs by their IR spectra in addition to the retention time in the gas chromatographic column. In comparison to Fourier Transform IR systems the EC-QCL setup shows a good mechanical robustness and has the advantage of a point light source. Because of the good fiber incoupling performance of the EC-QCL it is possible to use hollow fibers. So, a good absorption signal is achieved because of the long optical path in the small cell volume without significant dilution. In first laboratory experiments a detection limit in the microgram range for pseudo ephedrine is achieved.

  13. Gas-liquid mass transfer in a cross-flow hollow fiber module : Analytical model and experimental validation

    NARCIS (Netherlands)

    Dindore, V. Y.; Versteeg, G. F.

    2005-01-01

    The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations

  14. Weak polyelectrolyte multilayers as tunable separation layers for micro-pollutant removal by hollow fiber nanofiltration membranes

    NARCIS (Netherlands)

    Ilyas, Shazia; Mehran Abtahi, S.; Akkilic, Namik; Roesink, Hendrik Dirk Willem; de Vos, Wiebe Matthijs

    2017-01-01

    The presence of micro-pollutants in wastewater and in drinking water and its sources, is posing both environmental and health concerns. This work describes the development of weak polyelectrolyte multilayer (PEM) based hollow fiber nanofiltration (NF) membranes to remove micro-pollutants from

  15. Modeling the Transverse Shell-side Mass Transfer in Hollow Fiber Membrane Contactors at Low Reynolds Numbers

    Science.gov (United States)

    Kirsch, V. A.; Volkov, V. V.; Bildukevich, A. V.

    A method for calculating the external mass transfer in a contactor with a transverse confined flow of a viscous incompressible liquid (gas) past hollow fibers at low Reynolds numbers is proposed. The method is based on the concept of regular arrays of parallel fibers with a well-defined flowfield. As a simplest model system, a row of parallel fibers is considered, for which dependences of a drag force and an efficiency of a solute retention on the inter-fiber distance, membrane mass transfer coefficient, Peclet and Reynolds numbers are computed. The influence of the fluid inertia on the mass transport is studied. It is shown that a linear Stokes equations can be used for as higher Re numbers, as denser is the fiber array. In this case the flow field is independent on the Re number, and analytical solutions for the flowfield and fiber sorption efficiency (fiber Sherwood number) can be used.

  16. Further developments of capillary absorption spectrometers using small hollow-waveguide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.; Kriesel, Jason M.

    2014-05-01

    Our objective is to enhance quantification of stable carbon and oxygen isotope ratios to better than 1‰ relative isotope precision for sample sizes < 1 pico-mole. A newer variant Capillary Absorption Spectrometer (CAS) is described using a proprietary linear-taper hollow waveguide in conjunction with wavelength and frequency modulation techniques of tunable laser absorption spectrometry. Previous work used circular capillaries with uniform 1 mm ID to measure 13C/12C ratios with ≥ 20 pico-mole samples to ≤ 10 ppm (1‰ precision against standards) [1]. While performing fairly well, it generated residual modal noise due to multipath propagation in the hollow-waveguides (HWGs). This system has been utilized with laser ablation-catalytic combustion techniques to analyze small resolution (~ 25 μm spot diameter) laser ablation events on solids. Using smaller ID capillary waveguides could improve detection limits and spatial resolutions. Reducing an IR compatible hollow waveguide’s inner diameter (ID) to < 300 μm, reduces modal noise significantly for mid-IR operation, but feedback noise with high gain semiconductor lasers can become problematic. A proprietary linear-taper small waveguide (mean ID = 0.35 mm, L = 1 m) was tested to understand whether modal noise and optical feedback effects could be simultaneously reduced. We see better mode filtering and, significant reductions of feedback noise under favorable coupling of a multi-spatial mode QC laser to the smaller ID of the linear-tapered HWG. We demonstrate that better modal coupling operation is consistent with Liouville’s theorem, where greater suppression of feedback from spurious scatter within the HWG occurs by injecting the laser into the smaller ID port. Our progress on developing lighter weight, potentially fieldable alternatives to Isotope Ratio Mass Spectrometers (IRMS) with a small volume (≤ 0.1 cm3) CAS system will be discussed and compared to other competitive systems.

  17. Bandpass transmission filters based on phase shifted fiber Bragg gratings in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Ortega, Beatriz; Min, Rui; Sáez-Rodri­guez, David

    2017-01-01

    In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moir......é structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability...... of the fabricated devices has been also measured under different pre-strain conditions....

  18. Coherent light transmission properties of commercial photonic crystal hollow core optical fiber.

    Science.gov (United States)

    Cranch, G A; Miller, G A

    2015-11-01

    Photonic crystal hollow core fiber (PC-HCF) has enabled many exciting new applications in nonlinear optics and spectroscopy. However, to date there has been less impact in coherent applications where preservation of optical phase over long fiber lengths is crucial. This paper presents characteristics of three commercially available PC-HCFs relevant to coherent applications including higher-order mode analysis, birefringence and polarization-dependent loss, and their impact on coherent light transmission in PC-HCF. Multipath interference due to higher-order mode propagation and Fresnel reflection is shown to generate excess intensity noise in transmission, which can be suppressed by up to 20 dB through high frequency phase modulation of the source laser. To demonstrate the potential of PC-HCF in high performance sensing, a Mach-Zehnder interferometer (MZI) incorporating 10 m of PC-HCF in each arm is characterized and demonstrates a phase resolution (59×10(-9)  rad/Hz(1/2) at 30 kHz) close to the shot noise limit, which is better than can be achieved in a MZI made with the same length of single mode solid core fiber because of the limit set by fundamental thermodynamic noise (74×10(-9)  rad/Hz(1/2) at 30 kHz).

  19. Diesel Exhaust After-Treatment by Silicon Carbide Fiber Filter

    Directory of Open Access Journals (Sweden)

    Kazuhiro Yamamoto

    2014-04-01

    Full Text Available To reduce particulate matter (PM in diesel exhaust gas, a diesel particulate filter (DPF has been developed. The thermal durability of existing platinum catalyst-supported DPFs is inadequate. We are focusing on a non-catalytic after-treatment of silicon carbide (SiC fibers with highly thermal durability. In this study, we simulated the processes of soot deposition and oxidation. Results show that even in exhaust gas without soot, a complex flow pattern is observed. The porosity of the filter is not constant along the flow direction, and the pressure gradient varies. The friction factor is slightly larger than the predicted value by the empirical equation in uniform porous media flow. Since the soot deposition occurs inside the filter, the depth filtration by SiC fibers was confirmed. In addition, the effects of filter temperature and oxygen concentration are clearly revealed. That is, comparing the oxidation at 700 °C, the deposited soot amount at 1200 and 1400 °C is decreased by 60% and 92%, respectively. Raising the oxygen concentration from 10% to 20% increases the oxidation efficiency from 42% to 64%. Although more work is needed over a wide range of operating conditions, a combination of these two parameters is important to achieve the non-catalytic exhaust after-treatment.

  20. Slow-light enhanced absorption in a hollow-core fiber.

    Science.gov (United States)

    Grgić, Jure; Xiao, Sanshui; Mørk, Jesper; Jauho, Antti-Pekka; Mortensen, N Asger

    2010-06-21

    Light traversing a hollow-core photonic band-gap fiber may experience multiple reflections and thereby a slow-down and enhanced optical path length. This offers a technologically interesting way of increasing the optical absorption of an otherwise weakly absorbing material which can infiltrate the fibre. However, in contrast to structures with a refractive index that varies along the propagation direction, like Bragg stacks, the translationally invariant structures studied here feature an intrinsic trade-off between light slow-down and filling fraction that limits the net absorption enhancement. We quantify the degree of absorption enhancement that can be achieved and its dependence on key material parameters. By treating the absorption and index on equal footing, we demonstrate the existence of an absorption-induced saturation of the group index that itself limits the maximum absorption enhancement that can be achieved.

  1. Hollow fiber gas-liquid membrane contactors for acid gas capture: a review.

    Science.gov (United States)

    Mansourizadeh, A; Ismail, A F

    2009-11-15

    Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas-liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas-liquid membrane contactors for acid gas removal were also briefly discussed.

  2. Numerical Simulation and Analysis of CO2 Removal in a Polypropylene Hollow Fiber Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Zhien Zhang

    2014-01-01

    Full Text Available This present study shows a comprehensive 2D numerical model for removal of CO2 in a polypropylene (PP hollow fiber membrane contactor (HFMC using the computational fluid dynamics (CFD method. Monoethanolamine (MEA solution was used as the liquid absorbent in a nonwetting mode. The simulation results represented that higher liquid velocity and concentration and lower gas velocity and concentration led to higher percent of CO2 removal. The most proper parameters for CO2 removal were less than 1 mol m−3 gas concentration and 0.2 m s−1 gas flow rate, and for MEA the values were above 8 mol m−3 concentration and approximately 1 m s−1 liquid velocity. Furthermore, the model was validated with the experiment results. Therefore, the modeling results provided references to the selection of absorbents and operation parameters in the experimental study and pilot-scale applications.

  3. Linear and nonlinear modeling of light propagation in hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Roberts, John; Lægsgaard, Jesper

    2009-01-01

    Hollow core photonic crystal fibers (HC-PCFs) find applications which include quantum and non-linear optics, gas detection and short high-intensity laser pulse delivery. Central to most applications is an understanding of the linear and nonlinear optical properties. These require careful modeling...... due to the multitude of lengthscales involved and non-standard variations in properties such as the mode-field distribution. Linear mode-solvers require many 100,000's of basis functions to resolve the field variations, and extra terms are often required in descriptions of nonlinear propagation....... The intricacies of modeling various forms of HC-PCF are reviewed. An example of linear dispersion engineering, aimed at reducing and flattening the group velocity dispersion, is then presented. Finally, a study of short high intensity pulse delivery using HC-PCF in both dispersive and nonlinear (solitonic...

  4. Hyperlayer hollow-fiber flow field-flow fractionation of cells.

    Science.gov (United States)

    Reschiglian, Pierluigi; Zattoni, Andrea; Roda, Barbara; Cinque, Leonardo; Melucci, Dora; Min, Byung Ryul; Moon, Myeong Hee

    2003-01-24

    Interest in low-cost, analytical-scale, highly efficient and sensitive separation methods for cells, among which bacteria, is increasing. Particle separation in hollow-fiber flow field-flow fractionation (HF FlFFF) has been recently improved by the optimization of the HF FIFFF channel design. The intrinsic simplicity and low cost of this HF FlFFF channel allows for its disposable usage. which is particularly appealing for analytical bio-applications. Here, for the first time, we present a feasibility study on high-performance, hyperlayer HF FIFFF of micrometer-sized bacteria (Escherichia coli) and of different types of cells (human red blood cells, wine-making yeast from Saccharomyces cerevisiae). Fractionation performance is shown to be at least comparable to that obtained with conventional, flat-channel hyperlayer FIFFF of cells, at superior size-based selectivity and reduced analysis time.

  5. A pseudobiospecific hollow fiber cartridge for in vitro adsorption of autoantibodies from pathological serum

    Directory of Open Access Journals (Sweden)

    R.C.A. Ventura

    2000-12-01

    Full Text Available The affinity filtration technique using histidine as a pseudobiospecific ligand immobilized on poly(ethylene vinyl alcohol hollow fiber membranes (His-PEVA was used to remove autoantibodies from serum of patients with autoimmune disease. The effects of buffering solution conditions on the efficiency of autoantibodies removal was studied. The removal of anti-dsDNA, anti-SS-A/Ro, anti-Sm, anti-Sm/RNP and anti-cardiolipin autoantibodies present in the serum was investigated, comparing the efficiency between Hepes and Tris-HCl buffers. The results showed the potential of the membrane to remove all the autoantibodies studied. Anti SS-A/Ro was removed more efficiently in Tris-HCl buffer system rather than with the Hepes buffer.

  6. High Pressure Gases in Hollow Core Photonic Crystal Fiber:A New Nonlinear Medium

    CERN Document Server

    Azhar, Mohiudeen; Chang, Wonkeun; Joly, Nicolas; Russell, Philip

    2012-01-01

    The effective Kerr nonlinearity of hollow-core kagome-style photonic crystal fiber (PCF) filled with argon gas increases over 100 times when the pressure is increased from 1 to 150 bar, reaching 15 % of that of bulk silica glass, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering : absent in noble gases and having an extremely high optical damage threshold. As a result, detailed and well controlled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixed-frequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability side-band and a soliton created dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realisation of reconfigurable s...

  7. Hollow core photonic crystal fiber for monitoring leukemia cells using surface enhanced Raman scattering (SERS).

    Science.gov (United States)

    Khetani, Altaf; Momenpour, Ali; Alarcon, Emilio I; Anis, Hanan

    2015-11-01

    The present paper demonstrates an antibody-free, robust, fast, and portable platform for detection of leukemia cells using Raman spectroscopy with a 785-nm laser diode coupled to a hollow core photonic crystal (HC-PCF) containing silver nanoparticles. Acute myeloid leukemia is one of the most common bone marrow cancers in children and youths. Clinical studies suggest that early diagnosis and remission evaluation of myoblasts in the bone marrow are pivotal for improving patient survival. However, the current protocols for leukemic cells detection involve the use of expensive antibodies and flow cytometers. Thus, we have developed a new technology for detection of leukemia cells up to 300 cells/ml using a compact fiber HC-PCF, which offers a novel alternative to existing clinical standards. Furthermore, we were also able to accurately distinguish live, apoptotic and necrotic leukemic cells.

  8. Semi-analytical model for hollow-core anti-resonant fibers

    Directory of Open Access Journals (Sweden)

    Wei eDing

    2015-03-01

    Full Text Available We detailedly describe a recently-developed semi-analytical method to quantitatively calculate light transmission properties of hollow-core anti-resonant fibers (HC-ARFs. Formation of equiphase interface at fiber’s outermost boundary and outward light emission ruled by Helmholtz equation in fiber’s transverse plane constitute the basis of this method. Our semi-analytical calculation results agree well with those of precise simulations and clarify the light leakage dependences on azimuthal angle, geometrical shape and polarization. Using this method, we show investigations on HC-ARFs having various core shapes (e.g. polygon, hypocycloid with single- and multi-layered core-surrounds. The polarization properties of ARFs are also studied. Our semi-analytical method provides clear physical insights into the light guidance in ARF and can play as a fast and useful design aid for better ARFs.

  9. Toluene impurity effects on CO2 separation using a hollow fiber membrane for natural gas

    KAUST Repository

    Omole, Imona C.

    2011-03-01

    The performance of defect-free cross-linkable polyimide asymmetric hollow fiber membranes was characterized using an aggressive feed stream containing up to 1000ppm toluene. The membrane was shown to be stable against toluene-induced plasticization compared with analogs made from Matrimid®, a commercial polyimide. Permeation and sorption analysis suggest that the introduction of toluene vapors in the feed subjects the membrane to antiplasticization, as the permeance decreases significantly (to less than 30%) under the most aggressive conditions tested. Separation efficiencies reflected by permselectivities were less affected. The effect of the toluene on the membrane was shown to be reversible when the toluene was removed. © 2010 Elsevier B.V.

  10. Wavelength scaling of optimal hollow-core fiber compressors in the single-cycle limit.

    Science.gov (United States)

    Granados, Eduardo; Chen, Li-Jin; Lai, Chien-Jen; Hong, Kyung-Han; Kärtner, Franz X

    2012-04-09

    We systematically investigate supercontinuum generation using three-dimensional numerical simulations of nonlinear femtosecond pulse propagation in hollow-core fibers (HCF) at different pump wavelengths ranging from 400 nm to 2 μm. A general design strategy for HCF compressors is presented, maximizing the spectral broadening while preserving high beam quality for given pump pulse energy, duration and wavelength. We show close fitting of the modeled results with simple analytical formulas, enabling the construction of high-energy pulse compressors at the wavelength range of interest. Based on the presented wavelength scaling study, we propose an orthogonally polarized two-color pumping scheme in a single HCF compressor for the coherent synthesis of the electric fields in the sub-cycle regime with mJ level energies.

  11. Modeling and parametric analysis of hollow fiber membrane system for carbon capture from multicomponent flue gas

    KAUST Repository

    Khalilpour, Rajab

    2011-08-12

    The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2/N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. © 2011 American Institute of Chemical Engineers (AIChE).

  12. Counteracting ammonia inhibition in anaerobic digestion by removal with a hollow fiber membrane contactor.

    Science.gov (United States)

    Lauterböck, B; Ortner, M; Haider, R; Fuchs, W

    2012-10-01

    The aim of the current study was to investigate the feasibility of membrane contactors for continuous ammonia (NH₃-N) removal in an anaerobic digestion process and to counteract ammonia inhibition. Two laboratory anaerobic digesters were fed slaughterhouse wastes with ammonium (NH₄⁺) concentrations ranging from 6 to 7.4 g/L. One reactor was used as reference reactor without any ammonia removal. In the second reactor, a hollow fiber membrane contactor module was used for continuous ammonia removal. The hollow fiber membranes were directly submerged into the digestate of the anaerobic reactor. Sulfuric acid was circulated in the lumen as an adsorbent solution. Using this set up, the NH₄⁺-N concentration in the membrane reactor was significantly reduced. Moreover the extraction of ammonia lowered the pH by 0.2 units. In combination that led to a lowering of the free NH₃-N concentration by about 70%. Ammonia inhibition in the reference reactor was observed when the concentration exceeded 6 g/L NH₄⁺-N or 1-1.2 g/L NH₃-N. In contrast, in the membrane reactor the volatile fatty acid concentration, an indicator for process stability, was much lower and a higher gas yield and better degradation was observed. The chosen approach offers an appealing technology to remove ammonia directly from media having high concentrations of solids and it can help to improve process efficiency in anaerobic digestion of ammonia rich substrates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Synthesis and characterization of polycaprolactone urethane hollow fiber membranes as small diameter vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Pagán, Ángel E. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Stahl, Alexander M. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Chemistry, Stanford University, Stanford, CA (United States); Ramseier, Michelle L. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Chemical Engineering, Stanford University, Stanford, CA (United States); Behn, Anthony W. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Department of Bioengineering, Stanford University, Stanford, CA (United States)

    2016-07-01

    The design of bioresorbable synthetic small diameter (< 6 mm) vascular grafts (SDVGs) capable of sustaining long-term patency and endothelialization is a daunting challenge in vascular tissue engineering. Here, we synthesized a family of biocompatible and biodegradable polycaprolactone (PCL) urethane macromers to fabricate hollow fiber membranes (HFMs) as SDVG candidates, and characterized their mechanical properties, degradability, hemocompatibility, and endothelial development. The HFMs had smooth surfaces and porous internal structures. Their tensile stiffness ranged from 0.09 to 0.11 N/mm and their maximum tensile force from 0.86 to 1.03 N, with minimum failure strains of approximately 130%. Permeability varied from 1 to 14 × 10{sup −6} cm/s, burst pressures from 1158 to 1468 mm Hg, and compliance from 0.52 to 1.48%/100 mm Hg. The suture retention forces ranged from 0.55 to 0.81 N. HFMs had slow degradation profiles, with 15 to 30% degradation after 8 weeks. Human endothelial cells proliferated well on the HFMs, creating stable cell layer coverage. Hemocompatibility studies demonstrated low hemolysis (< 2%), platelet activation, and protein adsorption. There were no significant differences in the hemocompatibility of HFMs in the absence and presence of endothelial layers. These encouraging results suggest great promise of our newly developed materials and biodegradable elastomeric HFMs as SDVG candidates. - Highlights: • Polyester urethane hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties varied according to composition. • HFM inner and outer surfaces were successfully seeded with cells. • HFMs showed excellent hemocompatibility in vitro. • HFM has the potential to be used for small diameter vascular grafts.

  14. Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Pagán, Ángel E.; Kang, Yunqing [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Findlay, Michael W. [Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA (United States); University of Melbourne Department of Surgery, Royal Melbourne Hospital, Parkville, VIC (Australia); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States)

    2015-04-01

    Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10{sup −6} cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts.

  15. Analysis of flux reduction behaviors of PRO hollow fiber membranes: Experiments, mechanisms, and implications

    KAUST Repository

    Xiong, Jun Ying

    2016-01-15

    Pressure retarded osmosis (PRO) is a promising technology to harvest renewable osmotic energy using a semipermeable membrane. However, a significant flux reduction has been always observed that severely shrinks the harvestable power to a level only marginally higher or even lower than the economically feasible value. This work focuses on the elucidation of various underlying mechanisms responsible for the flux reduction. First, both inner-selective and outer-selective thin film composite (TFC) hollow fiber membranes are employed to examine how the fundamental internal factors (such as the surface salinity of the selective layer at the feed side (CF,m) and its components) interact with one another under the fixed bulk salinity gradient, resulting in various behaviours of external performance indexes such as water flux, reverse salt flux, and power density. Then, the research is extended to investigate the effects of the growing bulk feed salinity due to the accumulated reverse salt flux along PRO modules. Finally, the insights obtained from the prior two stationary conditions are combined with the advanced nucleation theory to elucidate the dynamic scaling process by visualizing how the multiple fundamental factors (such as local supersaturation, nucleation rate and nuclei size) evolve and interplay with one another in various membrane regimes during the whole scaling process. To our best knowledge, it is the first time that the advanced nucleation theory is applied to study the PRO scaling kinetics in order to provide subtle and clear pictures of the events occurring inside the membrane. This study may provide useful insights to design more suitable TFC hollow fiber membranes and to operate them with enhanced water flux so that the PRO process may become more promising in the near future.

  16. Amino-functionalized surface modification of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Leiqing; Cheng, Jun, E-mail: juncheng@zju.edu.cn; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2017-08-15

    Highlights: • Amino group was introduced to improve surface polarity of PDMS membrane. • The water contact angle of PDMS membrane decreased after the modification. • The concentration of N atom on surface of PDMS membrane reached up to ∼6%. • The density of PDMS membrane decreased while the swelling degree increased. • CO{sub 2} permeability increased while selectivity decreased after the modification. - Abstract: This study aimed to improve surface polarity of polydimethylsiloxane (PDMS) membranes and provide surface active sites which were easy to react with other chemicals. 3-Aminopropyltriethoxysilane (APTES) containing an amino group was introduced into a PDMS membrane by crosslinking to prepare polyacrylonitrile hollow fiber-supported PDMS membranes with an amino-functionalized surface. Fourier transform infrared and X-ray photoelectron spectroscopic analyses proved the existence of APTES and its amino group in the PDMS membrane. The concentration of N atoms on the PDMS membrane surface reached ∼6% when the mass ratio of APTES/PDMS oligomer in the PDMS coating solution was increased to 4/3. The water contact angle decreased from ∼114° to ∼87.5°, indicating the improved surface polarization of the PDMS membrane. The density and swelling degree of the PDMS membrane decreased and increased, respectively, with increasing APTES content in PDMS. This phenomenon increased CO{sub 2} permeability and decreased CO{sub 2}/H{sub 2} selectivity, CO{sub 2}/CH{sub 4} selectivity, and CO{sub 2}/N{sub 2} selectivity. When the mass ratio of APTES/PDMS oligomer was increased from 0 to 4/3, the CO{sub 2} permeation rate of the hollow fiber-supported PDMS membranes initially decreased from ∼2370 GPU to ∼860 GPU and then increased to ∼2000 GPU due to the change in coating solution viscosity.

  17. A nitric oxide releasing self-assembled peptide amphiphile nanomatrix for improving the biocompatibility of microporous hollow fibers

    Science.gov (United States)

    El-Ferzli, George T; Andukuri, Adinarayana; Alexander, Grant; Scopel, Michaella; Ambalavanan, Namasivayam; Patel, Rakesh P; Jun, Ho-Wook

    2015-01-01

    Oxygenators are critical components of extracorporeal circuits used frequently in cardiopulmonary bypass and intensive care, but platelet activation and induction of a complex inflammatory response are usually observed with their use. To improve the biocompatibility of oxygenators, we developed a nitric oxide (NO)-releasing, self-assembled peptide amphiphile nanomatrix. The nanomatrix formed a homogenous coating over the microporous hollow fibers as demonstrated by scanning electron microscopy. We quantitated platelet adhesion to the artificial fibers by measuring absorbance/area of platelets (Abs/A; nm/m2) using acid phosphatase assay. There was a 17-fold decrease in platelet adhesion to the nanomatrix (Abs/A = 0.125) compared to collagen controls (Abs/A = 2.07; p0.05) in a bench top test circuit at different flow rates as estimated by change in partial pressure of oxygen in relation to water velocity through fibers. These findings demonstrate the feasibility of coating microporous hollow fibers with a NO-releasing, self-assembled amphiphile nanomatrix that may improve the biocompatibility of the hollow fibers without affecting their gas exchange capacity. PMID:26102178

  18. The red shift of the semiconductor quantum dots luminescence maximum in the hollow core photonic crystal fibers

    Science.gov (United States)

    Chibrova, Anastasiya A.; Shuvalov, Andrey A.; Skibina, Yulia S.; Pidenko, Pavel S.; Pidenko, Sergey A.; Burmistrova, Natalia A.; Goryacheva, Irina Y.

    2017-11-01

    Hollow core microstructural optical waveguides (photonic crystal fibers) can affect intensity and spectrum position of luminophores emission located in the hollow core. Most strongly this effects could be in case of luminescence semiconductor nanoparticles - quantum dots (QDs) due to the narrow and symmetrical photoluminescence spectra. Study of the spectral effects arising from the superposition of QDs luminescence band on the photonic band gaps in the fiber transmission spectrum is both of fundamental and applied interest. This paper demonstrates the red shift of photoluminescence maximum of CdSe/ZnS QDs with core-shell structures. Luminescence maximum shift can be more than 10 nm, depending on the position of the photonic band gaps in the fiber transmission spectrum.

  19. Miniature and robust optical fiber in-line Mach-Zehnder interferometer based on a hollow ellipsoid.

    Science.gov (United States)

    Gong, H; Wang, D N; Xu, B; Ni, K; Liu, H; Zhao, C L

    2015-08-01

    An optical fiber in-line Mach-Zehnder interferometer based on a hollow ellipsoid fabricated by femtosecond laser micromachining and fusion-splicing technique is demonstrated. The surface of the hollow ellipsoid acts as an internal mirror that can be utilized for the construction of an interferometer. Such an interferometer device is miniature and robust and can perform external refractive index, curvature, and high-temperature sensing in a mutually independent way, and hence a simultaneous multiple parameter measurement capability can be readily achieved.

  20. Composite polymer/oxide hollow fiber contactors: versatile and scalable flow reactors for heterogeneous catalytic reactions in organic synthesis.

    Science.gov (United States)

    Moschetta, Eric G; Negretti, Solymar; Chepiga, Kathryn M; Brunelli, Nicholas A; Labreche, Ying; Feng, Yan; Rezaei, Fateme; Lively, Ryan P; Koros, William J; Davies, Huw M L; Jones, Christopher W

    2015-05-26

    Flexible composite polymer/oxide hollow fibers are used as flow reactors for heterogeneously catalyzed reactions in organic synthesis. The fiber synthesis allows for a variety of supported catalysts to be embedded in the walls of the fibers, thus leading to a diverse set of reactions that can be catalyzed in flow. Additionally, the fiber synthesis is scalable (e.g. several reactor beds containing many fibers in a module may be used) and thus they could potentially be used for the large-scale production of organic compounds. Incorporating heterogeneous catalysts in the walls of the fibers presents an alternative to a traditional packed-bed reactor and avoids large pressure drops, which is a crucial challenge when employing microreactors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Generation of multiple VUV dispersive waves using a tapered gas-filled hollow-core anti-resonant fiber

    DEFF Research Database (Denmark)

    Habib, Md Selim; Markos, Christos; Bang, Ole

    2017-01-01

    Hollow-core anti-resonant (HC-AR) fibers are perhaps the best platform for ultrafast nonlinear optics based on light-gas interactions because they offer broadband guidance and low-loss guidance. The main advantage of using gases inside HC fibers is that both the dispersion and nonlinearity can...... the nonlinear process to further blue-shift the generated DWs towards vacuum ultra-violet (VUV), here we numerically demonstrate for the first time (to the best of our knowledge) how the use of a tapered Ar-filled HC-AR fiber leads to multiple DWs in the extreme wavelength region from 143 to 280 nm....

  2. A Biohybrid Artificial Lung Prototype With Active Mixing of Endothelialized Microporous Hollow Fibers

    Science.gov (United States)

    Polk, Alexa A.; Maul, Timothy M.; McKeel, Daniel T.; Snyder, Trevor A.; Lehocky, Craig A.; Pitt, Bruce; Stolz, Donna Beer; Federspiel, William J.; Wagner, William R.

    2014-01-01

    Acute respiratory distress syndrome (ARDS) affects nearly 150,000 patients per year in the US, and is associated with high mortality (≈40%) and suboptimal options for patient care. Mechanical ventilation and extracorporeal membrane oxygenation are limited to short-term use due to ventilator-induced lung injury and poor bio-compatibility, respectively. In this report, we describe the development of a biohybrid lung prototype, employing a rotating endothelialized microporous hollow fiber (MHF) bundle to improve blood biocompatibility while MHF mixing could contribute to gas transfer efficiency. MHFs were surface modified with radio frequency glow discharge (RFGD) and protein adsorption to promote endothelial cell (EC) attachment and growth. The MHF bundles were placed in the biohybrid lung prototype and rotated up to 1,500 revolutions per minute (rpm) using speed ramping protocols to condition ECs to remain adherent on the fibers. Oxygen transfer, thrombotic deposition, and EC p-selectin expression were evaluated as indicators of biohybrid lung functionality and biocompatibility. A fixed aliquot of blood in contact with MHF bundles rotated at either 250 or 750 rpm reached saturating pO2 levels more quickly with increased rpm, supporting the concept that fiber rotation would positively contribute to oxygen transfer. The presence of ECs had no effect on the rate of oxygen transfer at lower fiber rpm, but did provide some resistance with increased rpm when the overall rate of mass transfer was higher due to active mixing. RFGD followed by fibronectin adsorption on MHFs facilitated near confluent EC coverage with minimal p-selectin expression under both normoxic and hyperoxic conditions. Indeed, even subconfluent EC coverage on MHFs significantly reduced thrombotic deposition adding further support that endothelialization enhances, blood biocompatibility. Overall these findings demonstrate a proof-of-concept that a rotating endothelialized MHF bundle enhances gas

  3. Bonded carbon or ceramic fiber composite filter vent for radioactive waste

    Science.gov (United States)

    Brassell, Gilbert W.; Brugger, Ronald P.

    1985-02-19

    Carbon bonded carbon fiber composites as well as ceramic or carbon bonded ceramic fiber composites are very useful as filters which can separate particulate matter from gas streams entraining the same. These filters have particular application to the filtering of radioactive particles, e.g., they can act as vents for containers of radioactive waste material.

  4. Polyethyleneimine-Functionalized Polyamide Imide (Torlon) Hollow-Fiber Sorbents for Post-Combustion CO 2 Capture

    KAUST Repository

    Li, Fuyue Stephanie

    2013-05-24

    Carbon dioxide emitted from existing coal-fired power plants is a major environmental concern due to possible links to global climate change. In this study, we expand upon previous work focused on aminosilane-functionalized polymeric hollow-fiber sorbents by introducing a new class of polyethyleneimine (PEI)-functionalized polymeric hollow-fiber sorbents for post-combustion carbon dioxide capture. Different molecular weight PEIs (Mn≈600, 1800, 10 000, and 60 000) were studied as functional groups on polyamide imide (PAI, Torlon) hollow fibers. This imide ring-opening modification introduces two amide functional groups and was confirmed by FTIR attenuated total reflectance spectroscopy. The carbon dioxide equilibrium sorption capacities of PEI-functionalized Torlon materials were characterized by using both pressure decay and gravimetric sorption methods. For equivalent PEI concentrations, PAI functionalized with lower molecular weight PEI exhibited higher carbon dioxide capacities. The effect of water in the ring-opening reaction was also studied. Up to a critical value, water in the reaction mixture enhanced the degree of functionalization of PEI to Torlon and resulted in higher carbon dioxide uptake within the functionalized material. Above the critical value, roughly 15 % w/w water, the fiber morphology was lost and the fiber was soluble in the solvent. PEI-functionalized (Mn≈600) PAI under optimal reaction conditions was observed to have the highest CO2 uptake: 4.9 g CO2 per 100 g of polymer (1.1 mmol g-1) at 0.1 bar and 35°C with dry 10 % CO2/90 % N2 feed for thermogravimetric analysis. By using water-saturated feeds (10 % CO2/90 % N2 dry basis), CO2 sorption was observed to increase to 6.0 g CO2 per 100 g of sorbent (1.4 mmol g-1). This material also demonstrated stability in cyclic adsorption-desorption operations, even under wet conditions at which some highly effective sorbents tend to lose performance. Thus, PEI-functionalized PAI fibers can be

  5. Analysis of CO2 separation and simulation of a partially wetted hollow fiber membrane contactor.

    Science.gov (United States)

    Keshavarz, P; Fathikalajahi, J; Ayatollahi, S

    2008-04-15

    A steady state model was developed for a microporous hollow fiber membrane contactor operated under partially wetted conditions accompanied by chemical reactions, to analyze CO2 absorption into the aqueous solution of diethanolamine (DEA). The proposed diffusion-reaction model contains reversible chemical reactions in the liquid bulk as well as wetted parts of the membrane pores. A numerical scheme was employed to solve the simultaneous nonlinear mathematical expressions, and the results were validated with experimental data in the literature. The gas phase concentration and velocity profile in axial direction inside the shell, liquid concentration profile in axial and radial directions inside the fibers, and also those within the wetted parts of the pores were predicted by using the model. The results of the model and proposed numerical scheme show that membrane wetting, even in very low fractions, can decrease the absorption flux significantly. The wetting fraction of membrane was predicted both with and without consideration of chemical reactions inside the wetted pores. The results indicate that the chemical reactions inside the wetted pores, which have been disregarded in the literature, have considerable effects on the prediction of membrane wetting fraction.

  6. Analysis of ammonia separation from purge gases in microporous hollow fiber membrane contactors.

    Science.gov (United States)

    Karami, M R; Keshavarz, P; Khorram, M; Mehdipour, M

    2013-09-15

    In this study, a mathematical model was developed to analyze the separation of ammonia from the purge gas of ammonia plants using microporous hollow fiber membrane contactors. A numerical procedure was proposed to solve the simultaneous linear and non linear partial differential equations in the liquid, membrane and gas phases for non-wetted or partially wetted conditions. An equation of state was applied in the model instead of Henry's law because of high solubility of ammonia in water. The experimental data of CO₂-water system in the literature was used to validate the model due to the lack of data for ammonia-water system. The model showed that the membrane contactor can separate ammonia very effectively and with recoveries higher than 99%. SEM images demonstrated that ammonia caused some micro-cracks on the surfaces of polypropylene fibers, which could be an indication of partial wetting of membrane in long term applications. However, the model results revealed that the membrane wetting did not have significant effect on the absorption of ammonia because of very high solubility of ammonia in water. It was also found that the effect of gas velocity on the absorption flux was much more than the effect of liquid velocity. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Hollow Fiber Spacesuit Water Membrane Evaporator Development and Testing for Advanced Spacesuits

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis A.; Tsioulos, Gus; Settles, Joseph; Colunga, Aaron; Vogel, Matthew; Vonau, Walt

    2010-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform the thermal control function for advanced spacesuits to take advantage of recent advances in micropore membrane technology in providing a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. Principles of a sheet membrane SWME design were demonstrated using a prototypic test article that was tested in a vacuum chamber at JSC in July 1999. The Membrana Celgard X50-215 microporous hollow fiber (HoFi) membrane was selected after recent contamination tests as the most suitable candidate among commercial alternatives for HoFi SWME prototype development. A design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype consisting 14,300 tube bundled into 30 stacks, each of which are formed into a chevron shape and separated by spacers and organized into three sectors of ten nested stacks. Vacuum chamber testing has been performed characterize heat rejection as a function of inlet water temperature and water vapor backpressure and to show contamination resistance to the constituents expected to be found in potable water produced by the distillation processes. Other tests showed the tolerance to freezing and suitability to reject heat in a Mars pressure environment.

  8. Outer-selective pressure-retarded osmosis hollow fiber membranes from vacuum-assisted interfacial polymerization for osmotic power generation

    KAUST Repository

    Sun, Shipeng

    2013-11-19

    In this paper, we report the technical breakthroughs to synthesize outer-selective thin-film composite (TFC) hollow fiber membranes, which is in an urgent need for osmotic power generation with the pressure-retarded osmosis (PRO) process. In the first step, a defect-free thin-film composite membrane module is achieved by vacuum-assisted interfacial polymerization. The PRO performance is further enhanced by optimizing the support in terms of pore size and mechanical strength and the TFC layer with polydopamine coating and molecular engineering of the interfacial polymerization solution. The newly developed membranes can stand over 20 bar with a peak power density of 7.63 W/m2, which is equivalent to 13.72 W/m2 of its inner-selective hollow fiber counterpart with the same module size, packing density, and fiber dimensions. The study may provide insightful guidelines for optimizing the interfacial polymerization procedures and scaling up of the outer-selective TFC hollow fiber membrane modules for PRO power generation. © 2013 American Chemical Society.

  9. Outer-selective pressure-retarded osmosis hollow fiber membranes from vacuum-assisted interfacial polymerization for osmotic power generation.

    Science.gov (United States)

    Sun, Shi-Peng; Chung, Tai-Shung

    2013-11-19

    In this paper, we report the technical breakthroughs to synthesize outer-selective thin-film composite (TFC) hollow fiber membranes, which is in an urgent need for osmotic power generation with the pressure-retarded osmosis (PRO) process. In the first step, a defect-free thin-film composite membrane module is achieved by vacuum-assisted interfacial polymerization. The PRO performance is further enhanced by optimizing the support in terms of pore size and mechanical strength and the TFC layer with polydopamine coating and molecular engineering of the interfacial polymerization solution. The newly developed membranes can stand over 20 bar with a peak power density of 7.63 W/m(2), which is equivalent to 13.72 W/m(2) of its inner-selective hollow fiber counterpart with the same module size, packing density, and fiber dimensions. The study may provide insightful guidelines for optimizing the interfacial polymerization procedures and scaling up of the outer-selective TFC hollow fiber membrane modules for PRO power generation.

  10. A Modified EPA Method 1623 that Uses Tangential Flow Hollow-Fiber Ultrafiltration and Heat Dissociation Steps to Detect Waterborne Cryptosporidum and Giardia spp.

    Science.gov (United States)

    This protocol describes the use of a tangential flow hollow-fiber ultrafiltration sample concentration system and a heat dissociation as alternative steps for the detection of waterborne Cryptosporidium and Giardia species using EPA Method 1623.

  11. Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.

    1994-08-04

    This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

  12. Hollow Fiber Flight Prototype Spacesuit Water Membrane Evaporator Design and Testing

    Science.gov (United States)

    Bue, Grant; Vogel, Matt; Makinen, Janice; Tsioulos, Gus

    2010-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform thermal control for advanced spacesuits and to take advantage of recent advances in micropore membrane technology. This results in a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. The Membrana Celgard X50-215 microporous hollow-fiber (HoFi) membrane was selected after recent extensive testing as the most suitable candidate among commercial alternatives for continued SWME prototype development. The current design was based on a previous design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape. This was developed into a full-scale prototype consisting of 14,300 tube bundled into 30 stacks, each of which is formed into a chevron shape and separated by spacers and organized into three sectors of 10 nested stacks. The new design replaced metal components with plastic ones, and has a custom built flight like backpressure valve mounted on the side of the SWME housing to reduce backpressure when fully open. The spacers that provided separation of the chevron fiber stacks were eliminated. Vacuum chamber testing showed improved heat rejection as a function of inlet water temperature and water vapor backpressure compared with the previous design. Other tests pushed the limits of tolerance to freezing and showed suitability to reject heat in a Mars pressure environment with and without a sweep gas. Tolerance to contamination by constituents expected to be found in potable water produced by distillation processes was tested in a conventional way by allowing constituents to accumulate in the coolant as evaporation occurs. For this purpose, the SWME cartridge has endured an equivalent of 30 EVAs exposure and demonstrated minimal performance decline.

  13. Tunable fiber polarizing filter based on a single-hole-infiltrated polarization maintaining photonic crystal fiber.

    Science.gov (United States)

    Guo, Junqi; Liu, Yan-ge; Wang, Zhi; Han, Tingting; Huang, Wei; Luo, Mingming

    2014-04-07

    A tunable fiber polarizing filter based on selectively filling a single hole of a solid-core polarization maintaining photonic crystal fiber with high index liquid are proposed and demonstrated. Two groups of polarization-dependent resonance dips in the transmission spectrum of the single-hole-infiltrated photonic crystal fiber are observed. Theoretical and experimental investigations reveal that these resonant dips result from the couplings between the silica core fundamental mode at x or y polarization and high order modes (TM(01), TE(01) and HE(11)) in the liquid core. Especially, a distinctive characteristic near the strongest resonant point (SRP) is demonstrated and revealed. The transmission loss and spectral shape at the SRP wavelength are extremely sensitive to the filling length and temperature (or Refractive Index, RI), which permits a fiber bandpass or bandstop polarizing filter with a good performance on tunability and controllability. Furthermore, the narrowband dips on both sides of the SRP wavelength have wavelength-dependent tuning velocities, providing a method to achieve flexible and controllable filters as well as two- or multi-parameter sensors with a compact structure.

  14. Integrated SDS removal and protein digestion by hollow fiber membrane based device for SDS-assisted proteome analysis.

    Science.gov (United States)

    Xia, Simin; Yuan, Huiming; Chen, Yuanbo; Liang, Zheng; Zhang, Lihua; Zhang, Yukui

    2015-08-15

    In this work, a novel integrated sample preparation device for SDS-assisted proteome analysis was developed, by which proteins dissolved in 4% (w/v) SDS were first diluted by 50% methanol, and then SDS was online removed by a hollow fiber membrane interface (HFMI) with 50mM ammonium bicarbonate (pH 8.0) as an exchange buffer, finally digested by an immobilized enzyme reactor (IMER). To evaluate the performance of such an integrated device, bovine serum albumin dissolved in 4% (w/v) SDS as a model sample was analyzed; it could be found that similar to that obtained by direct analysis of BSA digests without SDS (the sequence coverage of 60.3±1.0%, n=3), with HFMI as an interface for SDS removal, BSA was identified with the sequence coverage of 61.0±1.0% (n=3). However, without SDS removal by HFMI, BSA could not be digested by the IMER and none peptides could be detected. In addition, such an integrated sample preparation device was also applied for the analysis of SDS extracted proteins from rat brain, compared to those obtained by filter-aided sample preparation (FASP), not only the identified protein group and unique peptide number were increased by 12% and 39% respectively, but also the sample pretreatment time was shortened from 24h to 4h. All these results demonstrated that such an integrated sample preparation device would provide an alternative tool for SDS assisted proteome analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Development of a High Performance PES Ultrafiltration Hollow Fiber Membrane for Oily Wastewater Treatment Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Noor Adila Aluwi Shakir

    2015-12-01

    Full Text Available This study attempts to optimize the spinning process used for fabricating hollow fiber membranes using the response surface methodology (RSM. The spinning factors considered for the experimental design are the dope extrusion rate (DER, air gap length (AGL, coagulation bath temperature (CBT, bore fluid ratio (BFR, and post-treatment time (PT whilst the response investigated is rejection. The optimal spinning conditions promising the high rejection performance of polyethersulfone (PES ultrafiltration hollow fiber membranes for oily wastewater treatment are at the dope extrusion rate of 2.13 cm3/min, air gap length of 0 cm, coagulation bath temperature of 30 °C, and bore fluid ratio (NMP/H2O of 0.01/99.99 wt %. This study will ultimately enable the membrane fabricators to produce high-performance membranes that contribute towards the availability of a more sustainable water supply system.

  16. Application of pseudo-emulsion-based hollow fiber strip dispersion for the extraction of p-nitrophenol from aqueous solutions.

    Science.gov (United States)

    Naidu, Gedela Ashok Kumar; Gupta, Smita; Chakraborty, Mousumi

    2016-11-01

    The extraction of p-nitrophenol (PNP) from aqueous solutions through a pseudo-emulsion hollow fiber strip dispersion (PEHFSD) system was conducted in a microporous hydrophobic polypropylene hollow fiber membrane contactor. For the optimization of the process variables, face-centered central composite design (FCCD) has been used. It was observed that initial feed concentration, carrier composition and stripping phase concentration were the three FCCD factors, which influenced the nitrophenol extraction. Using the optimized process conditions for the separation of PNP, experiments were also performed for the separation of other nitrophenols through PEHFSD system. By the FCCD design and analysis, almost 99% extraction of all three nitrophenols was achieved at optimum conditions. A mass transfer model was also developed and aqueous and membrane resistances were evaluated as 196.46 s cm(-1) and 50.14 s cm(-1), respectively.

  17. Foulant analysis of hollow fine fiber (HFF) membranes in Red Sea SWRO plants using membrane punch autopsy (MPA)

    KAUST Repository

    Green, Troy N.

    2017-06-12

    Membrane punch autopsy (MPA) is a procedure for quantitative foulant analysis of hollow fine fiber (HFF) permeators. In the past, quantitative autopsies of membranes were restricted to spiral wound. This procedure was developed at SWCC laboratories and tested on permeators of two commercial Red Sea reverse osmosis plants. For membrane autopsies, stainless steel hollow bore picks were penetrated to membrane cores and fibers extracted for foulant analysis. Quantitative analysis of extracted materials contained inorganic and organic foulants including bacteria. Fourier transform infrared spectroscopy analysis confirmed the presence of organic fouling functional groups and scanning electron microscopy with energy dispersive X-ray spectroscopy in the presence of diatoms and silica most likely not from particulate sand. API analysis revealed the presence of Shewanella and two Vibrio microbial species confirmed by 16S rDNA sequence library. It was observed that fouling content of HFF cellulose triacetate (CTA) membranes were more than 800 times than polyamide spiral wound membranes.

  18. Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

    Directory of Open Access Journals (Sweden)

    Pereira C.C.

    2000-01-01

    Full Text Available During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

  19. High Performance Spatial Filter Array Based on Signal Mode Fiber Bundle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Loveraging on Agiltron's experience in optical fiber components, Agiltron proposed a coherent single-mode fiber (SMF) spatial filter array (SFA) with a gradient...

  20. Chloride reduction from brackish water by hollow fiber supported liquid membranes (HFSLM) using ionic liquids as a carrier

    OpenAIRE

    Hofmeister, Markus; Slusarek, Tobias; Madaj, Rafal; Strömbäck, William

    2013-01-01

    The project “Chloride reduction from brackish water by hollow fiber supported liquid membranes (HFSLM) using ionic liquids as a carrier “ is about developing an alternative and cost effective solution for the Abrera drinking water treatment plant to desalinate water from Llobregat river while accomplishing drinking water standards. With a constant increase of the world's population, the demand for drinking water also increases. However, the supply of drinking water is limited, so desalination...

  1. Monitoring of cell viability and cell growth in a hollow-fiber bioreactor by use of the dye Alamar Blue.

    Science.gov (United States)

    Gloeckner, H; Jonuleit, T; Lemke, H D

    2001-06-01

    We describe a method for monitoring cell proliferation in a small-scale hollow-fiber bioreactor (culture volume: 1 ml) by use of the Alamar Blue dye. Alamar Blue is a non-fluorescent compound, which yields a fluorescent product after reduction, e.g. by living cells. In contrast to the MTT-assay, the Alamar Blue assay does not lead to cell death. However, when not removed from the cells, the Alamar Blue dye shows a reversible, time- and concentration-dependent growth inhibition as observed for the leukemic cell lines CCRF-CEM, HL-60 and REH. When applied in the medium compartment of a hollow-fiber bioreactor system, the dye is delivered to the cells across the hollow-fiber membrane, reduced by the cells and released from the cell into the medium compartment back again. Thus, fluorescence intensity can be measured in medium samples reflecting growth of the cells in the cell compartment. This procedure offers several advantages. First, exposure of the cells to the dye can be reduced compared to conventional culture in plates. Second, handling steps are minimized since no sample of the cells needs to be taken for readout. Moreover, for the exchange of medium, a centrifugation step can be avoided and the cells can be cultivated further. Third, the method allows discriminating between cell densities of 10(5), 10(6) and 10(7) of proliferating HL-60 cells cultivated in the cell compartment of the bioreactor. Measurement of fluorescence in the medium compartment is more sensitive compared to glucose or lactate measurement for cell counts below 10(6) cells/ml, in particular. We conclude that the Alamar Blue-assay combined with a hollow-fiber bioreactor offers distinct advantages for the non-invasive monitoring of cell viability and proliferation in a closed system.

  2. A Raman cell based on hollow core photonic crystal fiber for human breath analysis.

    Science.gov (United States)

    Chow, Kam Kong; Short, Michael; Lam, Stephen; McWilliams, Annette; Zeng, Haishan

    2014-09-01

    Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors' goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Raman scattering is a photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm(-1). The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the visible wavelengths led to an estimated seven

  3. Osmotic Power Generation by Inner Selective Hollow Fiber Membranes: An investigation of thermodynamics, mass transfer, and module scale modelling

    KAUST Repository

    Xiong, Jun Ying

    2016-12-29

    A comprehensive analysis of fluid motion, mass transport, thermodynamics and power generation during pressure retarded osmotic (PRO) processes was conducted. This work aims to (1) elucidate the fundamental relationship among various membrane properties and operation parameters and (2) analyse their individual and combined impacts on PRO module performance. A state-of-the-art inner-selective thin-film composite (TFC) hollow fiber membrane was employed in the modelling. The analyses of mass transfer and Gibbs free energy of mixing indicate that the asymmetric nature of hollow fibers results in more significant external concentration polarization (ECP) in the lumen side of the inner-selective hollow fiber membranes. In addition, a trade-off relationship exists between the power density (PD) and the specific energy (SE). The PD vs. SE trade-off upper bound may provide a useful guidance whether the flowrates of the feed and draw solutions should be further optimized in order to (1) minimize the boundary thickness and (2) maximize the osmotic power generation. Two new terms, mass transfer efficiency and power harvesting efficiency for osmotic power generation, have been proposed. This work may provide useful insights to design and operate PRO modules with enhanced performance so that the PRO process becomes more promising in real applications in the near future.

  4. Pressure retarded osmosis dual-layer hollow fiber membranes developed by co-casting method and ammonium persulfate (APS) treatment

    KAUST Repository

    Fu, Fengjiang

    2014-11-01

    Delamination and low water permeability are two issues limiting the applications of dual-layer hollow fiber membranes in the pressure retarded osmosis (PRO) process. In this work, we first developed a universal co-casting method that is able to co-cast highly viscous dope solutions to form homogeneous dual-layer flat sheet membranes. By employing this method prior to the tedious dual-layer hollow fiber spinning process, both time and material consumptions are significantly saved. The addition of polyvinylpyrrolidone (PVP) is found to eliminate delamination at the sacrifice of water flux. A new post-treatment method that involves flowing ammonium persulfate (APS) solution and DI water counter-currently is potentially to remove the PVP molecules entrapped in the substrate while keeps the integrity of the interface. As the APS concentration increases, the water flux in the PRO process is increased while the salt leakage is slightly decreased. With the optimized APS concentration of 5wt%, the post-treated membrane shows a maximum power density of 5.10W/m2 at a hydraulic pressure of 15.0bar when 1M NaCl and 10mM NaCl were used as the draw and feed solutions, respectively. To the extent of our knowledge, this is the best phase inversion dual-layer hollow fiber membrane with an outer selective layer for osmotic power generation. © 2014 Elsevier B.V.

  5. Synthesis of ceramic hollow fiber supported zeolitic imidazolate framework-8 (ZIF-8) membranes with high hydrogen permeability

    KAUST Repository

    Pan, Yichang

    2012-12-01

    Purification and recovery of hydrogen from hydrocarbons in refinery streams in the petrochemical industry is an emerging research field in the study of membrane gas separation. Hollow fiber membrane modules can be easily implemented into separation processes at the industrial scale. In this report, hollow yttria-stabilized zirconia (YSZ) fiber-supported zeolitic imidazole framework-8 (ZIF-8) membranes were successfully prepared using a mild and environmentally friendly seeded growth method. Our single-component permeation studies demonstrated that the membrane had a very high hydrogen permeance (~15×10 -7mol/m 2sPa) and an ideal selectivity of H 2/C 3H 8 of more than 1000 at room temperature. This high membrane permeability and selectivity caused serious concentration polarization in the separation of H 2/C 3H 8 mixtures, which led to almost 50% drop in both the H 2 permeance and the separation factor. Enhanced mixing on the feed side could reduce the effect of the concentration polarization. Our experimental data also indicated that the membranes had excellent reproducibility and long-term stability, indicating that the hollow fiber-supported ZIF-8 membranes developed in this study have great potential in industry-scale separation of hydrogen. © 2012 Elsevier B.V.

  6. Hollow fiber stir bar sorptive extraction for determination of phthalic acid esters in environmental and biological matrices.

    Science.gov (United States)

    Li, Jia; Wang, Yan-Bin; Su, Qiong; Wu, Shang; Wu, Lan

    2017-02-01

    The purpose of this paper is to introduce a novel hollow fiber stir bar sorptive extraction for collecting and determining of phthalic acid esters in environmental and biological matrices. Shell-core ZrO2 /SiO2 composite microspheres and porous C18 silica microspheres were compared as the sorbents, which were loaded in the lumen of a microporous hollow fiber membrane. A thin stainless-steel wire was also inside of the hollow fiber membrane acting as the magnetic stirrer, thus affording the procedures like stir bar sorptive extraction to perform the active trapping of the analytes. Variables affecting the extraction (salt addition and pH of samples, extraction temperature, and time) and desorption (microwave time and eluted solvents) have been optimized. Under the optimal conditions, good linearity (r > 0.9968) of all calibration curves was obtained in validation experiments. And the limits of quantification ranged from 0.01 to 1000 ng/mL. The recoveries in different matrices were in the range of 64.90-112.60% with relative standard deviations less than 8.60%. The present work demonstrated the applicability of the developed method for the determination of phthalic acid esters in environmental and biological sample, allowing the selective extraction of phthalate esters in complex samples with low consumption of organic solvents and no sample clean-up. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hollow-fiber micro-extraction combined with HPLC for the determination of sitagliptin in urine samples

    Directory of Open Access Journals (Sweden)

    Rezaee Raheme

    2015-01-01

    Full Text Available This study successfully developed a three-phase hollow-fiber liquid phase micro extraction coupled with high performance liquid chromatography for determination of trace levels of an anti-diabetic drug, sitagliptin (STG, in urine samples. Sitagliptin was extracted from 15 mL of the basic sample solution with a pH of 8.5 into an organic extracting solvent (n-octanol impregnated in the pores of a hollow fiber and then back extracted into an acidified aqueous solution in the lumen of the hollow fiber with a pH of 3. After extraction, 20 µL of the acceptor phase was injected into HPLC. In order to obtain high extraction efficiency, the parameters affecting the HF-LPME including pH of the source and receiving phases, type of organic phase, ionic strength, stirring rate, extraction time, the volume ratio of donor phase to acceptor phase and temperature were studied and optimized. Under the optimized conditions, enrichment factors up to 88 were achieved and the relative standard deviation of the method was in the range of 3 % to 6%. The results indicated that HF-LPME method has an excellent clean-up capacity and a high preconcentration factor and can serve as a simple and sensitive method for monitoring the drug in the urine samples.

  8. Picosecond and nanosecond pulse delivery through a hollow-core Negative Curvature Fiber for micro-machining applications.

    Science.gov (United States)

    Jaworski, Piotr; Yu, Fei; Maier, Robert R J; Wadsworth, William J; Knight, Jonathan C; Shephard, Jonathan D; Hand, Duncan P

    2013-09-23

    We present high average power picosecond and nanosecond pulse delivery at 1030 nm and 1064 nm wavelengths respectively through a novel hollow-core Negative Curvature Fiber (NCF) for high-precision micro-machining applications. Picosecond pulses with an average power above 36 W and energies of 92 µJ, corresponding to a peak power density of 1.5 TWcm⁻² have been transmitted through the fiber without introducing any damage to the input and output fiber end-faces. High-energy nanosecond pulses (>1 mJ), which are ideal for micro-machining have been successfully delivered through the NCF with a coupling efficiency of 92%. Picosecond and nanosecond pulse delivery have been demonstrated in fiber-based laser micro-machining of fused silica, aluminum and titanium.

  9. Full-Scale Hollow Fiber Spacesuit Water Membrane Evaporator Prototype Development and Testing for Advanced Spacesuits

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Dillon, Paul; Weaver, Gregg

    2009-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform the thermal control function for advanced spacesuits to take advantage of recent advances in micropore membrane technology in providing a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. Principles of a sheet membrane SWME design were demonstrated using a prototypic test article that was tested in a vacuum chamber at JSC in July 1999. The Membrana Celgard X50-215 microporous hollow fiber (HoFi) membrane was selected after recent contamination tests as the superior candidate among commercial alternatives for HoFi SWME prototype development. Although a number of design variants were considered, one that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was deemed best for further development. An analysis of test data showed that eight layer stacks of the HoFi sheets that had good exposure on each side of the stack would evaporate water with high efficiency. A design that has 15,000 tubes, with 18 cm of exposed tubes between headers has been built and tested that meets the size, weight, and performance requirements of the SWME. This full-scale prototype consists of 30 stacks, each of which are formed into a chevron shape and separated by spacers and organized into three sectors of ten nested stacks. Testing has been performed to show contamination resistance to the constituents expected to be found in potable water produced by the distillation processes. Other tests showed the sensitivity to surfactants.

  10. Multi-objective Optimization of Solar-driven Hollow-fiber Membrane Distillation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, Sarah E. [Univ. of Arizona, Tucson, AZ (United States); Mirchandani, Sera [Univ. of Arizona, Tucson, AZ (United States); Karanikola, Vasiliki [Univ. of Arizona, Tucson, AZ (United States); Arnold, Robert G. [Univ. of Arizona, Tucson, AZ (United States); Saez, Eduardo [Univ. of Arizona, Tucson, AZ (United States)

    2017-09-01

    Securing additional water sources remains a primary concern for arid regions in both the developed and developing world. Climate change is causing fluctuations in the frequency and duration of precipitation, which can be can be seen as prolonged droughts in some arid areas. Droughts decrease the reliability of surface water supplies, which forces communities to find alternate primary water sources. In many cases, ground water can supplement the use of surface supplies during periods of drought, reducing the need for above-ground storage without sacrificing reliability objectives. Unfortunately, accessible ground waters are often brackish, requiring desalination prior to use, and underdeveloped infrastructure and inconsistent electrical grid access can create obstacles to groundwater desalination in developing regions. The objectives of the proposed project are to (i) mathematically simulate the operation of hollow fiber membrane distillation systems and (ii) optimize system design for off-grid treatment of brackish water. It is anticipated that methods developed here can be used to supply potable water at many off-grid locations in semi-arid regions including parts of the Navajo Reservation. This research is a collaborative project between Sandia and the University of Arizona.

  11. Designing the inner surface corrugations of hollow fibers to enhance CO2 absorption efficiency.

    Science.gov (United States)

    Fashandi, Hossein; Zarrebini, Mohammad; Ghodsi, Ali; Saghafi, Reza

    2016-08-15

    For the first time, a low cost strategy is introduced to enhance the efficiency of CO2 absorption using gas-liquid membrane contactors. This is implemented by designing the corrugations in the inner layer of poly(vinyl chloride) hollow fibers (PVC HFs) through changing the bore fluid composition. In fact, the number of corrugations in the HF inner layer is engineered via changing the phase separation time within the inner layer. Such that expedited phase separation leads to highly corrugated inner layer. In contrast, decelerated phase separation is responsible for reduced number of inner layer corrugations. Phase separation causes the initial polymer solution with low viscoelastic moduli to be transferred into polymer-rich domains with high viscoelastic moduli. These domains resist against stretching-induced radial forces toward the center of HF; therefore, the inner layer of HF buckles. Delayed phase separation defers formation of polymer-rich domains and hence, HF with less corrugated inner surface is expected. The phase separation within the HF inner layer is controlled through changing the rate of solvent/nonsolvent exchange. This is conducted by variation the solvent content in the bore fluid; as higher as solvent content, as slower as solvent/nonsolvent exchange. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Dispersion-free solvent extraction of Cr(VI) from acidic solutions using hollow fiber contactor.

    Science.gov (United States)

    Alguacil, Francisco J; Alonso, Manuel; Lopez, Félix A; Lopez-Delgado, Aurora; Padilla, Isabel

    2009-10-15

    The use of dispersión-free solvent extraction, through microporous hydrophobic membrane has been investigated. The hollow fiber contactor, with surface area of 1.4 m2 was used to extract Cr(VI) (0.005-0.12 g/L from aqueous sulphuric acidic media (pH 2.5-4.2 +/- 0.05). Several parameters such as extractant concentration, feed acidity and metal concentration in the initial aqueous solution were investigated. Results revealed that 15% v/v Cyanex 923 in Exxsol D-100 as organic phase and feed in the 2.5 pH range, gave optimum extraction (exceeding 95%) of Cr(VI) and it was possible to strip using 10 g/L hydrazine sulfate (also with recoveries exceeding 95%). In this step, Cr(VI) is immediately reduced to the less hazardous Cr(III) state. Results also showed that under the various experimental conditions, chromium(VI) extraction was rate-controlled by the interfacial reaction on the membrane surface. Typical overall mass transfer coefficients values are 4.2 x 10(-5) and 3.6 x 10(-6) cm/s for extraction and stripping operations, respectively.

  13. Non Dispersive Chemical Deacidification of Crude Palm Oil in Hollow Fiber Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Mubiar Purwasasmita

    2015-09-01

    Full Text Available Performance of chemical deacidification of crude palm oil (CPO using aqueous NaOH solution in a polysulfone hollow fiber ultrafiltration membrane was investigated. The effects of operating temperature, NaOH concentration and flow rates on percentage of free fatty acids (FFA removal, oil loss, soap entrainment and overall mass transfer coefficient were evaluated. Overall mass transfer coefficients, soap content in oil and neutral oil loss all increased when the temperature was increased from 60 to 70°C due to an increase of the FFA distribution value. A minimum 0.25 N of NaOH or a NaOH to FFA molar ratio of about 7.62 was required to facilitate the expected extraction efficiency. The increased oil flowrate slightly enhanced the solute transport kinetics, while the aqueous phase flowrate did not significantly influence deacidification efficiency or mass transfer coefficient. About 97% of FFA removal was achieved within 4 hours. The maximum oil loss observed was 11% and the highest soap content in the oil without separation step was 3150 ppm. The values of the overall mass transfer coefficient varied from 2.97×10-7 to 7.71×10-7 m/s. These results show the potential of using the non dispersive membrane contacting process for chemical deacidification of CPO as well as other vegetable oils.

  14. Enhanced Control of Transient Raman Scattering Using Buffered Hydrogen in Hollow-Core Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-12-01

    Many reports on stimulated Raman scattering in mixtures of Raman-active and noble gases indicate that the addition of a dispersive buffer gas increases the phase mismatch to higher-order Stokes and anti-Stokes sidebands, resulting in a preferential conversion to the first few Stokes lines, accompanied by a significant reduction in the Raman gain due to collisions with gas molecules. Here we report that, provided the dispersion can be precisely controlled, the effective Raman gain in a gas-filled hollow-core photonic crystal fiber can actually be significantly enhanced when a buffer gas is added. This counterintuitive behavior occurs when the nonlinear coupling between the interacting fields is strong and can result in a performance similar to that of a pure Raman-active gas, but at a much lower total gas pressure, allowing competing effects such as Raman backscattering to be suppressed. We report high modal purity in all the emitted sidebands, along with anti-Stokes conversion efficiencies as high as 5% in the visible and 2% in the ultraviolet. This new class of gas-based waveguide device, which allows the nonlinear optical response to be beneficially pressure-tuned by the addition of buffer gases, may find important applications in laser science and spectroscopy.

  15. Ozone mass transfer behaviors on physical and chemical absorption for hollow fiber membrane contactors.

    Science.gov (United States)

    Zhang, Yong; Li, Kuiling; Wang, Jun; Hou, Deyin; Liu, Huijuan

    2017-09-01

    To understand the mass transfer behaviors in hollow fiber membrane contactors, ozone fluxes affected by various conditions and membranes were investigated. For physical absorption, mass transfer rate increased with liquid velocity and the ozone concentration in the gas. Gas flow rate was little affected when the velocity was larger than the critical value, which was 6.1 × 10-3m/s in this study. For chemical absorption, the flux was determined by the reaction rate between ozone and the absorbent. Therefore, concentration, species, and pH affected the mass transfer process markedly. For different absorbents, the order of mass transfer rate was the same as the reaction rate constant, which was phenol, sodium nitrite, hydrogen peroxide, and oxalate. Five hydrophobic membranes with various properties were employed and the mass transfer behavior can be described by the Graetz-Lévèque equation for the physical absorption process. The results showed the process was controlled by liquid film and the gas phase conditions, and membrane properties did not affect the ozone flux. For the chemical absorption, gas film, membrane and liquid film affected the mass transfer together, and none of them were negligible.

  16. Hollow fiber integrated microfluidic platforms for in vitro Co-culture of multiple cell types.

    Science.gov (United States)

    Huang, Jen-Huang; Harris, Jennifer F; Nath, Pulak; Iyer, Rashi

    2016-10-01

    This study demonstrates a rapid prototyping approach for fabricating and integrating porous hollow fibers (HFs) into microfluidic device. Integration of HF can enhance mass transfer and recapitulate tubular shapes for tissue-engineered environments. We demonstrate the integration of single or multiple HFs, which can give the users the flexibility to control the total surface area for tissue development. We also present three microfluidic designs to enable different co-culture conditions such as the ability to co-culture multiple cell types simultaneously on a flat and tubular surface, or inside the lumen of multiple HFs. Additionally, we introduce a pressurized cell seeding process that can allow the cells to uniformly adhere on the inner surface of HFs without losing their viabilities. Co-cultures of lung epithelial cells and microvascular endothelial cells were demonstrated on the different platforms for at least five days. Overall, these platforms provide new opportunities for co-culturing of multiple cell types in a single device to reconstruct native tissue micro-environment for biomedical and tissue engineering research.

  17. Hollow fiber-mediated liquid-phase microextraction of chemical warfare agents from water.

    Science.gov (United States)

    Dubey, D K; Pardasani, Deepak; Gupta, A K; Palit, Meehir; Kanaujia, Pankaj K; Tak, Vijay

    2006-02-24

    Unambiguous detection and identification of chemical warfare agents (CWAs) and related compounds are of paramount importance from verification point of view of Chemical Weapons Convention (CWC). It requires development of fast, reliable, simple and reproducible sample preparation of CWAs from water which is likely to be contaminated during deliberate or inadvertent spread of CWAs. This work describes development of hollow fiber liquid-phase microextraction (HF-LPME) method for efficient extraction of CWAs (such as sarin, sulfur mustard and their analogues) from water followed by gas chromatography-mass spectrometric analysis. Extraction parameters, such as organic solvent, agitation, extraction time, and salt concentration were optimized. Best recoveries of target analytes were achieved using 1 microL trichloroethylene as extracting solvent, 1000 rpm stirring rate, 15 min extraction time, and 30% NaCl. Excellent precision was observed with less than 7.6% RSD. The limit of detection by HF-LPME was achieved up to 0.1 microg/L at 30% salt concentration.

  18. Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall

    KAUST Repository

    Wang, Kai Yu

    2009-04-01

    To develop high-flux and high-rejection forward osmosis (FO) membranes for water reuses and seawater desalination, we have fabricated polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membranes with a thin wall and a desired pore size via non-solvent induced phase inversion and chemically cross-linking modification. The cross-linking by p-xylylene dichloride can finely tune the mean pore size and enhance the salt selectivity. High water permeation flux and improved salt selectivity for water reuses were achieved by using the 2-h modified PBI NF membrane which has a narrow pore size distribution. Cross-linking at a longer time produces even a lower salt permeation flux potentially suitable for desalination but at the expense of permeation flux due to tightened pore sizes. It is found that draw solution concentration and membrane orientations are main factors determining the water permeation flux. In addition, effects of membrane morphology and operation conditions on water and salt transport through membrane have been investigated. © 2008 Elsevier Ltd. All rights reserved.

  19. Polyethersulfone flat sheet and hollow fiber membranes from solutions in ionic liquids

    KAUST Repository

    Kim, Dooli

    2017-06-10

    We fabricated flat-sheet and hollow fiber membranes from polyethersulfone (PES) solutions in two ionic liquids: 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP) and 1,3-dimethylimidazolium dimethyl phosphate ([MMIM]DMP). The solvents are non-volatile and less toxic than organic solvents, such as dimethylformamide (DMF). The membranes morphologies were compared with those of membranes prepared from solutions in DMF, using electron microscopy. Water permeance, solute rejection and mechanical strengths were evaluated. Membranes were applied to DNA separation. While membranes based on PES were successfully prepared, polysulfone (PSf) does not dissolve in the same ionic liquids. The discrepancy between PES and PSf could not be explained using classical Flory-Huggins theory, which does not consider the coulombic contributions in ionic liquids. The differences in solubility could be understood, by applying density functional theory to estimate the interaction energy between the different polymers and solvents. The theoretical results were supported by experimental measurements of intrinsic viscosity and dynamic light scattering (DLS).

  20. Flexural Strength of Carbon Fiber Reinforced Polymer Repaired Cracked Rectangular Hollow Section Steel Beams

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2015-01-01

    Full Text Available The flexural behavior of rectangular hollow section (RHS steel beams with initial crack strengthened externally with carbon fiber reinforced polymer (CFRP plates was studied. Eight specimens were tested under three-point loading to failure. The experimental program included three beams as control specimens and five beams strengthened with CFRP plates with or without prestressing. The load deflection curves were graphed and failure patterns were observed. The yield loads and ultimate loads with or without repairing were compared together with the strain distributions of the CFRP plate. It was concluded that yield loads of cracked beams could be enhanced with repairing. Meanwhile, the ultimate loads were increased to some extent. The effect of repair became significant with the increase of the initial crack depth. The failure patterns of the repaired specimens were similar to those of the control ones. Mechanical clamping at the CFRP plate ends was necessary to avoid premature peeling between the CFRP plate and the steel beam. The stress levels in CFRP plates were relatively low during the tests. The use of prestressing could improve the utilization efficiency of CFRP plates. It could be concluded that the patching repair could be used to restore the load bearing capacity of the deficient steel beams.

  1. Detection of amino acid neurotransmitters by surface enhanced Raman scattering and hollow core photonic crystal fiber

    Science.gov (United States)

    Tiwari, Vidhu S.; Khetani, Altaf; Monfared, Ali Momenpour T.; Smith, Brett; Anis, Hanan; Trudeau, Vance L.

    2012-03-01

    The present work explores the feasibility of using surface enhanced Raman scattering (SERS) for detecting the neurotransmitters such as glutamate (GLU) and gamma-amino butyric acid (GABA). These amino acid neurotransmitters that respectively mediate fast excitatory and inhibitory neurotransmission in the brain, are important for neuroendocrine control, and upsets in their synthesis are also linked to epilepsy. Our SERS-based detection scheme enabled the detection of low amounts of GLU (10-7 M) and GABA (10-4 M). It may complement existing techniques for characterizing such kinds of neurotransmitters that include high-performance liquid chromatography (HPLC) or mass spectrography (MS). This is mainly because SERS has other advantages such as ease of sample preparation, molecular specificity and sensitivity, thus making it potentially applicable to characterization of experimental brain extracts or clinical diagnostic samples of cerebrospinal fluid and saliva. Using hollow core photonic crystal fiber (HC-PCF) further enhanced the Raman signal relative to that in a standard cuvette providing sensitive detection of GLU and GABA in micro-litre volume of aqueous solutions.

  2. A strategy to determine operating parameters in tissue engineering hollow fiber bioreactors.

    Science.gov (United States)

    Shipley, R J; Davidson, A J; Chan, K; Chaudhuri, J B; Waters, S L; Ellis, M J

    2011-06-01

    The development of tissue engineering hollow fiber bioreactors (HFB) requires the optimal design of the geometry and operation parameters of the system. This article provides a strategy for specifying operating conditions for the system based on mathematical models of oxygen delivery to the cell population. Analytical and numerical solutions of these models are developed based on Michaelis-Menten kinetics. Depending on the minimum oxygen concentration required to culture a functional cell population, together with the oxygen uptake kinetics, the strategy dictates the model needed to describe mass transport so that the operating conditions can be defined. If c(min) ≫ K(m) we capture oxygen uptake using zero-order kinetics and proceed analytically. This enables operating equations to be developed that allow the user to choose the medium flow rate, lumen length, and ECS depth to provide a prescribed value of c(min) . When c(min) />K(m), we use numerical techniques to solve full Michaelis-Menten kinetics and present operating data for the bioreactor. The strategy presented utilizes both analytical and numerical approaches and can be applied to any cell type with known oxygen transport properties and uptake kinetics. Copyright © 2011 Wiley Periodicals, Inc.

  3. Sound Absorption Properties Of Single-Hole Hollow Polyester Fiber Reinforced Hydrogenated Carboxyl Nitrile Rubber Composites

    Directory of Open Access Journals (Sweden)

    Jie Hong

    2017-09-01

    Full Text Available A series of single-hole hollow polyester fiber (SHHPF reinforced hydrogenated carboxyl nitrile rubber (HXNBR composites were fabricated. In this study, the sound absorption property of the HXNBR/SHHPF composite was tested in an impedance tube, the composite morphology was characterized by scanning electron microscope (SEM, and the tensile mechanical property was measured by strength tester. The results demonstrated that a remarkable change in sound absorption can be observed by increasing the SHHPF content from 0% to 40%. In the composite with 40% SHHPF in 1 mm thickness, the sound absorption coefficient reached 0.671 at 2,500 Hz; the effective bandwidth was 1,800-2,500 Hz for sound absorption coefficient larger than 0.2. But the sound absorption property of the composite deteriorated when the SHHPF content increased to 50% in 1 mm thickness. While with 20% SHHPF proportion, the sound absorption property was improved by increasing the thickness of composites from 1 to 5 mm. Compared with the pure HXNBR of the same thickness, the tensile mechanical property of the composite improved significantly by increasing the SHHPF proportion. As a lightweight composite with excellent sound absorption property, the HXNBR/SHHPF composite has potential practical application value in the fields of engineering.

  4. Flue gas carbon capture using hollow fiber membrane diffuser-separator

    Science.gov (United States)

    Ariono, D.; Chandranegara, A. S.; Widodo, S.; Khoiruddin; Wenten, I. G.

    2018-01-01

    In this work, CO2 removal from flue gas using membrane diffuser–separator was investigated. Hollow fiber polypropylene membrane was used as the diffuser while pure water was used as the absorbent. Separation performance of the membrane diffuser–separator as a function of CO2 concentration (6-28%-vol.) and flow rate (gas: 0.8-1.55 L.min-1 and liquid: 0.2-0.7 L.min-1) was investigated and optimized. It was found that CO2 removal was significantly affected by CO2 concentration in the feed gas. On the other hand, CO2 flux was more influenced by flow rates of liquid and gas rather than concentration. The optimized CO2 removal (64%) and flux (1 x 10-4 mol.m-2.s-1) were obtained at the highest gas flow rate (1.55 L.min-1), the lowest liquid flow rate (0.2 L.min-1), and 6.2%-vol. of CO2 concentration. Outlet gas of the membrane diffuser system tends to carry some water vapor, which is affected by gas and liquid flow rate. Meanwhile, in the steady-state operation of the separator, the gas bubbles generated by the membrane diffuser take a long time to be completely degassed from the liquid phase, thus a portion of gas stream was exiting separator through liquid outlet.

  5. Pulsed-induced electromagnetically induced transparency in the acetylene-filled hollow-core fibers

    Science.gov (United States)

    Rodríguez, Nayeli Casillas; Stepanov, Serguei; Miramontes, Manuel Ocegueda; Hernández, Eliseo Hernández

    2017-06-01

    Experimental results on pulsed excitation of electromagnetically induced transparency (EIT) in the acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at pressures 0.1-0.4 Torr are reported. The EIT was observed both in Λ and V interaction configurations with the continuous probe wave tuned to R9 (1520.08 nm) acetylene absorption line and with the control pulses tuned to P11 (1531.58 nm) and P9 (1530.37 nm) lines, respectively. The utilized control pulses were of up to 40 ns duration with <2.5 ns fronts and with maximum input power 1 W. The maximum modulation depth of the initial probe wave absorption via EIT was up to 40 and 15% for the co- and counter-propagation of the probe and control waves, respectively, and importance of the waves polarization matching was demonstrated. For a qualitative explanation of reduction in the counter-propagation EIT efficiency a simple model of the accelerated mismatch of the two-frequency EIT resonance with deviation of the molecule thermal velocity from the resonance value was utilized. It was shown experimentally that the EIT efficiencies in both configurations do not depend on the longitudinal velocity of the molecules. The characteristic relaxation time of the of the EIT response was found to be about 9 ns, i.e., is close to the relaxation times T 1,2 of the acetylene molecules under the utilized experimental conditions.

  6. Development and characterization of microfiltration hollow-fiber modules for sterilization of fermentation media

    Directory of Open Access Journals (Sweden)

    Faria L.F.F.

    2002-01-01

    Full Text Available Sterilization of fermentation medium involving heat may result in undesirable chemical reactions that alter nutrient concentration and yield products, which interfere in the fermentation performance. Sterilization of heat-sensitive compounds usually involves separate sterilizations of carbon source and nutrient solution. Membrane separation processes are an alternative to thermal processes, as they have many advantages such as the possibility of continuous and modular operation and the use of moderate temperatures. In this context, the objective of this work was the preparation of hollow-fiber membranes and the design of modules suitable for continuous sterilization of fermentation medium. The membrane with the best performance had a maximum pore diameter of 0.2 mu m and a permeability of 42.9 L/m².bar.h for a glucose/peptone/yeast extract medium. A module with 0.26 m² of permeation area was built with these membranes. This module was able to provide a permeate flow rate of 2.2 L/h using a pressure difference of 0.2 bar. The collected permeate was completely sterile, thus confirming the efficiency of this process.

  7. Experimental investigation and modeling of industrial oily wastewater treatment using modified polyethersulfone ultrafiltration hollow fiber membranes

    Energy Technology Data Exchange (ETDEWEB)

    Salahi, Abdolhamid; Mohammadi, Toraj [Iran University of Science and Technology (IUST), Tehran (Iran, Islamic Republic of); Behbahani, Reza Mosayebi [Petroleum University of Technology (PUT), Ahwaz (Iran, Islamic Republic of); Hemmati, Mahmood [Research Institute of Petroleum Industry, Tehran (Iran, Islamic Republic of)

    2015-06-15

    Hollow fiber membranes were prepared from polyethersulfone/additives/NMP and DMSO system via phase inversion induced by precipitation in non-solvent coagulation bath. The interaction effects of polyethylene-glycol (PEG), propionic-acid (PA), Tween-20, PEG molecular weight and polyvinyl-pyrrolidone (PVP) on morphology and performance of synthesized membranes were investigated. Taguchi method (L{sub 16} orthogonal array) was used initially to plan a minimum number of experiments. 32 membranes were synthesized (with two replications) and their permeation flux and TOC rejection properties to oily wastewater treatment were studied. The obtained results indicated that addition of PA to spinning dope decreases flux while it increases TOC rejection of prepared membranes. Also, the result shows that addition of PVP, Tween-20 and PEG content in spinning dope enhances permeation flux while reducing TOC rejection. The obtained results indicated that the synthesized membranes was effective and suitable for treatment of the oily wastewater to achieve up to 92.6, 98.2, and 98.5% removal of TOC, TSS, and OGC, respectively with a flux of 247.19 L/(m{sup 2}h). Moreover, Hermia's models were used for permeation flux decline prediction. Experimental data and models predictions were compared. The results showed that there is reasonable agreement between experimental data and the cake layer model followed by the intermediate blocking model.

  8. Perovskite Hollow Fibers with Precisely Controlled Cation Stoichiometry via One-Step Thermal Processing.

    Science.gov (United States)

    Zhu, Jiawei; Zhang, Guangru; Liu, Gongping; Liu, Zhengkun; Jin, Wanqin; Xu, Nanping

    2017-05-01

    The practical applications of perovskite hollow fibers (HFs) are limited by challenges in producing these easily, cheaply, and reliably. Here, a one-step thermal processing approach is reported for the efficient production of high performance perovskite HFs, with precise control over their cation stoichiometry. In contrast to traditional production methods, this approach directly uses earth-abundant raw chemicals in a single thermal process. This approach can control cation stoichiometry by avoiding interactions between the perovskites and polar solvents/nonsolvents, optimizes sintering, and results in high performance HFs. Furthermore, this method saves much time and energy (≈ 50%), therefore pollutant emissions are greatly reduced. One successful example is Ba0.5Sr0.5Co0.8Fe0.2O3-δ HFs, which are used in an oxygen-permeable membrane. This exhibits high oxygen permeation flux values that exceed desired commercial targets and compares favorably with previously reported oxygen-permeable membranes. Studies on other perovskites have produced similarly successful results. Overall, this approach could lead to energy efficient, solid-state devices for industrial application in energy and environmental fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Hollow-fiber membrane bioreactor for the treatment of high-strength landfill leachate

    KAUST Repository

    Rizkallah, Marwan

    2013-07-15

    Performance assessment of membrane bioreactor (MBR) technology for the treatability of high-strength landfill leachate is relatively limited or lacking. This study examines the feasibility of treating high-strength landfill leachate using a hollow-fiber MBR. For this purpose, a laboratory-scale MBR was constructed and operated to treat leachate with a chemical oxygen demand (COD) of 9000-11,000 mg/l, a 5-day biochemical oxygen demand (BOD5) of 4000-6,000 mg/l, volatile suspended solids (VSS) of 300-500 mg/l, total nitrogen (TN) of 2000-6000 mg/l, and an ammonia-nitrogen (NH3-N) of 1800-4000 mg/l. VSS was used with the BOD and COD data to simulate the biological activity in the activated sludge. Removal efficiencies > 95-99% for BOD5, VSS, TN and NH3-N were attained. The coupled experimental and simulation results contribute in filling a gap in managing high-strength landfill leachate and providing guidelines for corresponding MBR application. © The Author(s) 2013.

  10. Evidence of specialized bromate-reducing bacteria in a hollow fiber membrane biofilm reactor.

    Science.gov (United States)

    Martin, K J; Downing, L S; Nerenberg, R

    2009-01-01

    Bromate is a carcinogenic disinfection by-product formed from bromide during ozonation or advanced oxidation. We previously observed bromate reduction in a hydrogen-based, denitrifying hollow fiber membrane biofilm reactor (MBfR). In this research, we investigated the potential existence of specialized bromate-reducing bacteria. Using denaturing gradient gel electrophoresis (DGGE), we compared the microbial ecology of two denitrifying MBfRs, one amended with nitrate as the electron acceptor and the other with nitrate plus bromate. The DGGE results showed that bromate exerted a selective pressure for a putative, specialized bromate-reducing bacterium, which developed a strong presence only in the reactor with bromate. To gain further insight into the capabilities of specialized, bromate-reducing bacteria, we explored bromate reduction in a control MBfR without any primary electron acceptors. A grown biofilm in the control MBfR reduced bromate without previous exposure, but the rate of reduction decreased over time, especially after perturbations resulting in biomass loss. The decrease in bromate reduction may have been the result of the toxic effects of bromate. We also used batch tests of the perchlorate-reducing pure culture, Dechloromonas sp. PC1 to test bromate reduction and growth. Bromate was reduced without measurable growth. Based on these results, we speculate bromate's selective pressure for the putative, specialized BRB observed in the DGGE was not growth related, but possibly based on resistance to bromate toxicity.

  11. Fabrication of Functionalized MOFs Incorporated Mixed Matrix Hollow Fiber Membrane for Gas Separation

    Directory of Open Access Journals (Sweden)

    Haitao Zhu

    2017-01-01

    Full Text Available The metal-organic framework (MOFs of MIL-53 was functionalized by aminosilane grafting and then incorporated into Ultem®1000 polymer matrix to fabricate mixed matrix hollow fiber membrane (MMHFM with high separation performance. SEM, XRD, and TGA were performed to characterize the functionalized MIL-53 and prepared MMHFM. The filler particles were embedded in membrane successfully and dispersed well in the polymer matrix. The incorporation of MOFs endowed MMHFM better thermal stability. Moreover, effects of solvent ratio in spinning dope, spinning condition, and testing temperature on gas separation performance of MMHFM were investigated. By optimizing dope composition, air gap distance, and bore fluid composition, MMHFM containing functionalized MIL-53 achieved excellent gas permeance and CO2/N2 selectivity. The CO2 permeance increased from 12.2 GPU for pure Ultem HFM to 30.9 GPU and the ideal CO2/N2 selectivity was enhanced from 25.4 to 34.7 simultaneously. Additionally, gas permeance increased but the selectivity decreased with the temperature increase, which followed the solution-diffusion based transport mechanism.

  12. Preparation and Preliminary Dialysis Performance Research of Polyvinylidene Fluoride Hollow Fiber Membranes

    Science.gov (United States)

    Zhang, Qinglei; Lu, Xiaolong; Liu, Juanjuan; Zhao, Lihua

    2015-01-01

    In this study, the separation properties of Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S) membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF) flux of pure water reached 108.2 L∙h−1∙m−2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM) were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA) had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%. PMID:25807890

  13. Performance of Hollow Fiber Ultrafiltration Membranes in the Clarification of Blood Orange Juice

    Directory of Open Access Journals (Sweden)

    Carmela Conidi

    2015-12-01

    Full Text Available The clarification of blood orange juice by ultrafiltration (UF was investigated by using three hollow fiber membrane modules characterized by different membrane materials (polysulfone (PS and polyacrylonitrile (PAN and molecular weight cut-off (MWCO (50 and 100 kDa. The performance of selected membranes was investigated in terms of productivity and selectivity towards total anthocyanin content (TAC, total phenolic content (TPC, and total antioxidant activity (TAA. All selected membranes allowed a good preservation of antioxidant compounds; however, the most suitable membrane for the clarification of the juice was found to be the PS 100 kDa membrane. In optimized operating conditions this membrane exhibited steady-state fluxes of 7.12 L/m2h, higher than those measured for other investigated membranes. Rejections towards TPC and TAA were of the order of 17.5% and 15%, respectively. These values were lower than those determined for PS 50 kDa and PAN 50 kDa membranes. In addition, the PS 100 kDa membrane exhibited a lower rejection (7.3% towards TAC when compared to the PS 50 kDa membrane (9.2%.

  14. Understanding the risk of scaling and fouling in hollow fiber forward osmosis membrane application

    KAUST Repository

    Majeed, Tahir

    2016-06-23

    Fouling studies of forward osmosis (FO) were mostly conducted based on fouling evaluation principals applied to pressure membrane processes such as reverse osmosis (RO)/nanofiltration (NF)/microfiltration (MF)/ultrafiltration (UF). For RO/NF/MF/UF processes, the single flux driving force (hydraulic pressure) remains constant, thus the fouling effect is easily evaluated by comparing flux data with the baseline. Whilst, the scenario of fouling effects for FO process is entirely different from RO/NF/MF/UF processes. Continuously changing driving force (osmotic pressure difference), the changes in concentration polarization associated with the varying draw solution/feed solution concentration and the fouling layer effects collectively influence the FO flux. Thus, usual comparison of the FO flux outcome with the baseline results can not exactly indicate the real affect of membrane fouling, rather presents a misleading cumulative effect. This study compares the existing FO fouling technique with an alternate fouling evaluation approach using two FO set-ups. Scaling and fouling risk for hollow fiber FO was separately investigated using synthetic water samples and model organic foulants as alginate, humic acid and bovine serum albumin. Results indicated that FO flux declines up to 5% and 49% in active layer-feed solution and active layer-draw solution orientations respectively.

  15. Preparation, ferromagnetic and photocatalytic performance of NiO and hollow Co{sub 3}O{sub 4} fibers through centrifugal-spinning technique

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Cong; Lin, Xuejun; Wang, Xinqiang, E-mail: xqwang@sdu.edu.cn; Liu, Hongjing; Liu, Benxue; Zhu, Luyi; Zhang, Guanghui; Xu, Dong

    2016-02-15

    Highlights: • NiO and hollow Co{sub 3}O{sub 4} fibers with the diameter of about 10 μm were prepared through centrifugal-spinning technique. • The evolution mechanism from precursor to crystalline fibers was explored. • Both NiO and hollow Co{sub 3}O{sub 4} fibers show ferromagnetism. • The NiO fibers exhibit good photocatalytic performance. - Abstract: Both NiO and hollow Co{sub 3}O{sub 4} fibers with the diameter of about 10 μm have been successfully prepared through spinning high viscous sols into precursor fibers and followed calcination process. The evolution process from precursor to crystalline fibers and the microstructures of the obtained fibers were characterized by TG-DSC, FT-IR, XRD, HRTEM, SEM and the like. The method is facile and cost-effective for mass production of fibers and the obtained fibers are pure phase with high crystallinity. Their magnetic properties were investigated, showing that both the fibers are ferromagnetic. Meanwhile, the NiO fibers exhibit good photocatalytic performance for the removal of Congo red from water under UV light irradiation.

  16. Method of making a continuous ceramic fiber composite hot gas filter

    Science.gov (United States)

    Hill, Charles A.; Wagner, Richard A.; Komoroski, Ronald G.; Gunter, Greg A.; Barringer, Eric A.; Goettler, Richard W.

    1999-01-01

    A ceramic fiber composite structure particularly suitable for use as a hot gas cleanup ceramic fiber composite filter and method of making same from ceramic composite material has a structure which provides for increased strength and toughness in high temperature environments. The ceramic fiber composite structure or filter is made by a process in which a continuous ceramic fiber is intimately surrounded by discontinuous chopped ceramic fibers during manufacture to produce a ceramic fiber composite preform which is then bonded using various ceramic binders. The ceramic fiber composite preform is then fired to create a bond phase at the fiber contact points. Parameters such as fiber tension, spacing, and the relative proportions of the continuous ceramic fiber and chopped ceramic fibers can be varied as the continuous ceramic fiber and chopped ceramic fiber are simultaneously formed on the porous vacuum mandrel to obtain a desired distribution of the continuous ceramic fiber and the chopped ceramic fiber in the ceramic fiber composite structure or filter.

  17. Real-time single airborne nanoparticle detection with nanomechanical resonant filter-fiber

    DEFF Research Database (Denmark)

    Schmid, Silvan; Kurek, Maksymilian; Adolphsen, Jens Q

    2013-01-01

    technique and gravimetric detection of airborne nanoparticles with a nanomechanical resonant filter-fiber. By increasing the nanoparticle momentum the dominant collection mechanism changes from diffusion to more efficient inertial impaction. In doing so we reach a single filter-fiber collection efficiency...

  18. Charged micropollutant removal with hollow fiber nanofiltration membranes based on polycation/polyzwitterion/polyanion multilayers

    NARCIS (Netherlands)

    de Grooth, Joris; Reurink, Dennis Maik; Ploegmakers, J.; de Vos, Wiebe Matthijs; Nijmeijer, Dorothea C.

    2014-01-01

    Hollow fiber nanofiltration membranes can withstand much higher foulant concentrations than their spiral wound counterparts and can be used in water purification without pretreatment. Still, the preparation of hollow fiber nanofiltration membranes is much less established. In this work, we demonstrate

  19. Widely tunable mode-locked fiber laser using carbon nanotube and LPG W-shaped filter.

    Science.gov (United States)

    Wang, Jie; Zhang, A Ping; Shen, Yong Hang; Tam, Hwa-yaw; Wai, P K A

    2015-09-15

    A widely tunable mode-locked fiber laser using a carbon nanotube absorber and a fiber-optic W-shaped spectral filter is presented. The W-shaped filter is constructed by sandwiching a phase-shifted long-period grating between two LPGs of different periods. By adjusting the temperature of the W-shaped filter from 23°C to 100°C, the central wavelength of the mode-locked fiber laser can be continuously tuned from 1597 to 1553 nm. The tuning range is further extended to 1531.6 nm when a shorter erbium-doped fiber is used in the fiber oscillator. The experimental results reveal that the large thermal tunability of the proposed LPG filter provides an effective approach to achieve compact widely tunable mode-locked fiber lasers covering both C and L bands.

  20. Monolithic all-PM femtosecond Yb-fiber laser stabilized with a narrow-band fiber Bragg grating and pulse-compressed in a hollow-core photonic crystal fiber

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Liu, Xiaomin; Lægsgaard, Jesper

    2008-01-01

    We report on an environmentally stable self-starting monolithic (i.e. without any free-space coupling) all-polarization-maintaining (PM) femtosecond Yb-fiber laser, stabilized against Q-switching by a narrow-band fiber Bragg grating and modelocked using a semiconductor saturable absorber mirror....... The laser output is compressed in a spliced-on hollow-core PM photonic crystal fiber, thus providing direct end-of-the-fiber delivery of pulses of around 370 fs duration and 4 nJ energy with high mode quality. Tuning the pump power of the end amplifier of the laser allows for the control of output pulse...

  1. Tunable Optical Filter Based on Mechanically Induced Cascaded Long Period Optical Fiber Grating

    Directory of Open Access Journals (Sweden)

    Sunita P. Ugale

    2013-01-01

    Full Text Available We have proposed and demonstrated experimentally a novel and simple tunable optical filter based on mechanically induced and cascaded long period optical fiber gratings. In this filter variable FWHM and center wavelength is provided by cascading long period and ultralong period optical fiber gratings with different periods in a novel fiber structure. We report here for the first time to our knowledge the characterization of mechanically induced long period fiber gratings with periods up to several millimeters in novel multimode-single-mode-multimode fiber structure. We have obtained maximum loss peak of around 20 dB.

  2. Extraction and quantification of SO2 content in wines using a hollow fiber contactor.

    Science.gov (United States)

    Plaza, Andrea; Romero, Julio; Silva, Wladimir; Morales, Elizabeth; Torres, Alejandra; Aguirre, María J

    2014-10-01

    Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH membrane extraction at 25 ℃. This operation is based on a hydrophobic Hollow Fiber Contactor, which separates the acidified red wine in the shell side and a diluted aqueous sodium hydroxide solution as receiving solution into the lumenside in countercurrent. Sulfite and bisulfite in the acidified red wine become molecular SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  3. Application of hollow fiber liquid phase microextraction for the determination of insecticides in water.

    Science.gov (United States)

    Lambropoulou, Dimitra A; Albanis, Triantafyllos A

    2005-04-22

    In the present work, a novel sample pre-treatment technique for the determination of trace concentrations of some insecticide compounds in aqueous samples has been developed and applied to the determination of the selected analytes in environmental water samples. The extraction procedure is based on coupling polypropylene hollow fiber liquid phase microextraction (HF-LPME) with gas chromatography by flame thermionic detection (GC-FTD). For the development of the method, seven organophosphorous insecticides (dichlorvos, mevinphos-cis, ethoprophos, chlorpyrifos methyl, phenthoate, methidathion and carbofenothion) and one carbamate (carbofuran) were considered as target analytes. Several factors that influence the efficiency of HF-LPME were investigated and optimized including agitation, organic solvent, sample volume, exposure time, salt additives and pH. The optimized methodology exhibited good linearity with correlation coefficient = 0.990. The analytical precision for the target analytes ranged from 4.3 to 11.1 for within-day variation and 4.6 to 12.0% for between-day variation. The detection limits for all analytes were found in the range from 0.001 to 0.072 microg/L, well below the limits established by the EC Drinking Water Directive (EEC 80/778). Relative recoveries obtained by the proposed method from drinking and river water samples ranged from 80 to 104% with coefficient of variations ranging from 4.5 to 10.7%. The present methodology is easy, rapid, sensitive and requires small sample volumes to screen environmental water samples for insecticide residues.

  4. Testing of Commercial Hollow Fiber Membranes for Space Suit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis; Tsioulos, Gus; Hanford, Anthony

    2009-01-01

    Three commercial-off-the-shelf (COTS) hollow fiber (HoFi) membrane evaporators, modified for low pressure, were tested in a vacuum chamber at pressures below 33 pascals as potential space suit water membrane evaporator (SWME) heat rejection technologies. Water quality was controlled in a series of 25 tests, first simulating potable water reclaimed from waste water and then changing periodically to simulate the ever concentrating make-up of the circulating coolant over that is predicted over the course of 100 EVAs. Two of the systems, comprised of non-porous tubes with hydrophilic molecular channels as the water vapor transport mechanism, were severely impacted by the increasing concentrations of cations in the water. One of the systems, based on hydrophobic porous polypropylene tubes was not affected by the degrading water quality, or the presence of microbes. The polypropylene system, called SWME 1, was selected for further testing. An inverse flow configuration was also tested with SWME 1, with vacuum exposure on the inside of the tubes, provided only 20% of the performance of the standard configuration. SWME 1 was also modified to block 50% and 90% of the central tube layers, and tested to investigate performance efficiency. Performance curves were also developed in back-pressure regulation tests, and revealed important design considerations arising from the fully closed valve. SWME 1 was shown to be insensitive to air bubbles injected into the coolant loop. Development and testing of a full-scale prototype based on this technology and these test results is in progress.

  5. Cross-correlated imaging of single-mode photonic crystal rod fiber with distributed mode filtering

    DEFF Research Database (Denmark)

    Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

    2013-01-01

    Photonic crystal bandgap fibers employing distributed mode filtering design provide near diffraction-limited light outputs, a critical property of fiber-based high-power lasers. Microstructure of the fibers is tailored to achieve single-mode operation at specific wavelength by resonant mode coupl...

  6. Performance of Hollow Fiber Membrane Gas-Liquid Contactors to Absorb CO2 Using Diethanolamine (Dea as a Solvent

    Directory of Open Access Journals (Sweden)

    Sutrasno Kartohardjono

    2010-10-01

    Full Text Available This study uses DEA solution to absorb CO2 from the gas flow through the hollow fiber membrane contactors. This study aims to evaluate the performance of hollow fiber membrane contactors to absorb CO2 gas using DEA solution as solvent through mass transfer and hydrodynamics studies. The use of DEA solution is to reduce the mass transfer resistance in the liquid phase, and on the other side, the large contact area of the membrane surface can cover the disadvantage of membrane contactors; additional mass transfer resistance in the membrane phase. During experiments, CO2 feed flows through the fiber lumens, while the 0.01 M DEA solution flows in the shell side of membrane contactors. Experimental results show that the mass transfer coefficients and fluxes of CO2 increase with an increase in both water and DEA solution flow rates. Increasing the amount of fibers in the contactors will decrease the mass transfer and fluxes at the same DEA solution flow rate. Mass transfer coefficients and CO2 fluxes using DEA solution can achieve 28,000 and 7.6 million times greater than using water as solvent, respectively. Hydrodynamics studies show that the liquid pressure drops in the contactors increase with increasing liquid flow rate and number of fibers in the contactors. The friction between water and the fibers in the contactor was more pronounced at lower velocities, and therefore, the value of the friction factor is also higher at lower velocities.

  7. Synthesis of La2O3 doped Zn2SnO4 hollow fibers by electrospinning method and application in detecting of acetone

    Science.gov (United States)

    Yang, H. M.; Ma, S. Y.; Yang, G. J.; Chen, Q.; Zeng, Q. Z.; Ge, Q.; Ma, L.; Tie, Y.

    2017-12-01

    Hollow porous pure and La2O3 doped Zn2SnO4 fibers were synthesized via single capillary electrospinning technology and used for obtaining of gas sensors. The as-prepared samples were characterized by microscopy, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy and UV-vis absorption spectra. The newly obtained gas sensors were investigated for acetone detection. Compared with pure Zn2SnO4 hollow fibers, the La2O3 doped Zn2SnO4 hollow fibers not only exhibited perfect sensing performance toward acetone with excellent selectivity, high response and fast response/recovery capability (7 s for adsorption and 9 s for desorption), but also the operating temperature was reduced from 240 °C to 200 °C. These results demonstrated that the special hollow porous La doped Zn2SnO4 fibers structures were used as the sensing material for fabricating high performance acetone sensors. The acetone sensing mechanism of La2O3 doped Zn2SnO4 hollow fibers was discussed too.

  8. Effect of using a cowl when measuring the fiber number concentration by the membrane filter method.

    Science.gov (United States)

    Kauffer, Edmond; Eypert-Blaison, Céline

    2004-05-01

    This article compares samples taken with three different sampling heads: (1). open-faced sampling head, (2). open-faced sampling head with stainless-steel extension cowl, and (3). open-faced sampling head with graphite-impregnated extension cowl. Sampling was performed in three factories producing man-made mineral fibers (alkaline silicate fibers, refractory ceramic fibers, glass fibers). Flow rate was varied (1 L/min or 2 L/min). The average densities measured on the sampling filter for fibers of fibers/mm(2). No significant difference in fiber density was observed in relation to the nature of the sampling head for fibers with a diameter of fibers until now. They were greater for fibers with a diameter of >3 microm than for those with a diameter of fibers, it would appear that cowl deposit can be reduced by increasing the sampling flow rate.

  9. All-fiber reflecting temperature probe based on the simplified hollow-core photonic crystal fiber filled with aqueous quantum dot solution.

    Science.gov (United States)

    Wu, Jian; Yin, Xiaojin; Wang, Wenyuan; Hong, Xueming; Du, Yu; Geng, Youfu; Li, Xuejin

    2016-02-10

    An all-fiber reflecting fluorescent temperature probe is proposed based on the simplified hollow-core photonic crystal fiber (SHC-PCF) filled with an aqueous CdSe/ZnS quantum dot solution. SHC-PCF is an excellent PCF used to fill liquid materials, which has low loss transmission bands in the visible wavelength range and enlarged core sizes. Both end faces of the SHC-PCF were spliced with multimode fiber after filling in order to generate a more stable and robust waveguide structure. The obtained temperature sensitivity dependence of the emission wavelength and the self-referenced intensity are 126.23 pm/°C and -0.007/°C in the temperature range of -10°C-120°C, respectively.

  10. High-throughput hydrolysis of starch during permeation across α-amylase-immobilized porous hollow-fiber membranes

    Science.gov (United States)

    Miura, Suguru; Kubota, Noboru; Kawakita, Hidetaka; Saito, Kyoichi; Sugita, Kazuyuki; Watanabe, Kohei; Sugo, Takanobu

    2002-02-01

    Two kinds of supporting porous membranes, ethanolamine (EA) and phenol (Ph) fibers, for immobilization of α-amylase were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, onto a porous hollow-fiber membrane, and subsequent ring-opening with EA and Ph, respectively. An α-amylase solution was forced to permeate radially outward through the pores of the EA and Ph fibers. α-Amylase was captured at a density of 0.15 and 6.6 g/L of the membrane by the graft chain containing 2-hydroxyethylamino and phenyl groups, respectively. A permeation pressure of 0.10 MPa provided a space velocity of 780 and 1500 h -1 for the α-amylase-immobilized EA and Ph fibers, respectively. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in the buffer across the α-amylase-immobilized Ph fiber was attained up to a space velocity of about 2000 h -1; this was achieved because of negligible diffusional mass-transfer resistance of the starch to the α-amylase due to convective flow, whereas an enzyme reaction-controlled system was observed for the α-amylase-immobilized EA fiber.

  11. Nonstationary coherent optical effects caused by pulse propagation through acetylene-filled hollow-core photonic-crystal fibers

    Science.gov (United States)

    Ocegueda, M.; Hernandez, E.; Stepanov, S.; Agruzov, P.; Shamray, A.

    2014-06-01

    Experimental observations of nonstationary coherent optical phenomena, i.e., optical nutation, free induction, and photon echo, in the acetylene (12C2H2) filled hollow-core photonic-crystal fiber (PCF) are reported. The presented results were obtained for the acetylene vibration-rotational transition P9 at wavelength 1530.37 nm at room temperature under a gas pressure of acetylene molecules' presence inside the effective PCF modal area and by intermolecule collisions. An accelerated attenuation of the optical nutation oscillations is explained by a random orientation of acetylene molecules.

  12. Design of a Polymer-Based Hollow-Core Bandgap Fiber for Low-Loss Terahertz Transmission

    DEFF Research Database (Denmark)

    Barh, Ajanta; Varshney, Ravi K.; Pal, Bishnu P.

    2016-01-01

    We use numerical simulations to design a hollow-core microstructured polymer optical fiber (HC-mPOF) suitable for broadband, terahertz (THz) pulse transmission with relatively low losses and small dispersion. The HC-mPOF consists of a central large air-core surrounded by periodically arranged wav...... of non-zero values of the longitudinal wavevector. We have achieved PBG over a broad spectral range (bandwidth similar to 400 GHz) ranging from 1.65 to 2.05 THz in the proposed HC-mPOF. The achievable loss coefficient in our designed HC-mPOF is...

  13. Application of hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction techniques in analytical toxicology

    Directory of Open Access Journals (Sweden)

    Vahid Sharifi

    2016-04-01

    Full Text Available The recent developments in hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction are reviewed. Applications of these newly emerging developments in extraction and preconcentration of a vast category of compounds including heavy metals, pesticides, pharmaceuticals and abused drugs in complex matrices (environmental and biological matrices are reviewed and discussed. The new developments in these techniques including the use of solvents lighter than water, ionic liquids and supramolecular solvents are also considered. Applications of these new solvents reduce the use of toxic solvents and eliminate the centrifugation step, which reduces the extraction time.

  14. Improvement of transmission properties of visible pilot beam for polymer-coated silver hollow fibers with acrylic silicone resin as buffer layer for sturdy structure

    Science.gov (United States)

    Iwai, Katsumasa; Takaku, Hiroyuki; Miyagi, Mitsunobu; Shi, Yi-Wei; Zhu, Xiao-Song; Matsuura, Yuji

    2017-02-01

    Flexible hollow fibers with 530-μm-bore size were developed for infrared laser delivery. Sturdy hollow fibers were fabricated by liquid-phase coating techniques. A silica glass capillary is used as the substrate. Acrylic silicone resin is used as a buffer layer and the buffer layer is firstly coated on the inner surface of the capillary to protect the glass tube from chemical damages due to the following silver plating process. A silver layer was inner-plated by using the conventional silver mirror-plating technique. To improve adhesion of catalyst to the buffer layer, a surface conditioner has been introduced in the method of silver mirror-plating technique. We discuss improvement of transmission properties of sturdy polymer-coated silver hollow fibers for the Er:YAG laser and red pilot beam delivery.

  15. Guidance and control of MIR TDL radiation via flexible hollow metallic rectangular pipes and fibers for possible LHS and other optical system compaction and integration

    Science.gov (United States)

    Yu, C.

    1983-01-01

    Flexible hollow metallic rectangular pipes and infrared fibers are proposed as alternate media for collection, guidance and manipulation of mid-infrared tunable diode laser (TDL) radiation. Certain features of such media are found to be useful for control of TDL far field patterns, polarization and possibly intensity fluctuations. Such improvement in dimension compatibility may eventually lead to laser heterodyne spectroscopy (LHS) and optical communication system compaction and integration. Infrared optical fiber and the compound parabolic coupling of light into a hollow pipe waveguide are discussed as well as the design of the waveguide.

  16. Direct-write PVDF nonwoven fiber fabric energy harvesters via the hollow cylindrical near-field electrospinning process

    Science.gov (United States)

    Liu, Z. H.; Pan, C. T.; Lin, L. W.; Huang, J. C.; Ou, Z. Y.

    2014-02-01

    One-dimensional piezoelectric nanomaterials have attracted great attention in recent years for their possible applications in mechanical energy scavenging devices. However, it is difficult to control the structural diameter, length, and density of these fibers fabricated by micro/nano-technologies. This work presents a hollow cylindrical near-field electrospinning (HCNFES) process to address production and performance issues encountered previously in either far-field electrospinning (FFES) or near-field electrospinning (NFES) processes. Oriented polyvinylidene fluoride (PVDF) fibers in the form of nonwoven fabric have been directly written on a glass tube for aligned piezoelectricity. Under a high in situ electrical poling field and strong mechanical stretching (the tangential speed on the glass tube collector is about 1989.3 mm s-1), the HCNFES process is able to uniformly deposit large arrays of PVDF fibers with good concentrations of piezoelectric β-phase. The nonwoven fiber fabric (NFF) is transferred onto a polyethylene terephthalate (PET) substrate and fixed at both ends using copper foil electrodes as a flexible textile-fiber-based PVDF energy harvester. Repeated stretching and releasing of PVDF NFF with a strain of 0.05% at 7 Hz produces a maximum peak voltage and current at 76 mV and 39 nA, respectively.

  17. A new modality for minimally invasive CO2 laser surgery: flexible hollow-core photonic bandgap fibers.

    Science.gov (United States)

    Shurgalin, Max; Anastassiou, Charalambos

    2008-01-01

    Carbon dioxide (CO2) lasers have become one of the most common surgical lasers due to excellent tissue interaction properties that offer precise control of cutting and ablation depth, minimal thermal damage to surrounding tissue, and good hemostasis. However, realization of the benefits offered by using surgical CO2 lasers in many endoscopic, minimally invasive surgical procedures has been inhibited by the absence of reliable, flexible fiber laser beam delivery systems. Recently, novel hollow-core photonic bandgap optical fibers for CO2 lasers were developed that offer high flexibility and mechanical robustness with good optical performance under tight bends. These fibers can be used through rigid and flexible endoscopes and various handpieces and will allow surgeons to perform delicate and precise laser surgery procedures in a minimally invasive manner. This paper describes the basic design of laser beam delivery system, different surgical fiber designs and their characteristics, and usage with existing surgical CO2 laser models. A few examples of successful CO2 laser surgeries performed with these fibers are presented.

  18. Improving femtosecond laser pulse delivery through a hollow core photonic crystal fiber for temporally focused two-photon endomicroscopy.

    Science.gov (United States)

    Choi, Heejin; So, Peter T C

    2014-10-15

    In this paper, we present a strategy to improve delivery of femtosecond laser pulses from a regenerative amplifier through a hollow core photonic crystal fiber for temporally focused wide-field two-photon endomicroscopy. For endomicroscope application, wide-field two-photon excitation has the advantage of requiring no scanning in the distal end. However, wide-field two-photon excitation requires peak power that is 10(4)-10(5) times higher than the point scanning approach corresponding to femtosecond pulses with energy on the order of 1-10 μJ at the specimen plane. The transmission of these high energy pulses through a single mode fiber into the microendoscope is a significant challenge. Two approaches were pursued to partially overcome this limitation. First, a single high energy pulse is split into a train of pulses with energy below the fiber damage threshold better utilizing the available laser energy. Second, stretching the pulse width in time by introducing negative dispersion was shown to have the dual benefit of reducing fiber damage probability and compensating for the positive group velocity dispersion induced by the fiber. With these strategy applied, 11 fold increase in the two photon excitation signal has been demonstrated.

  19. Hydrodynamic effects of air sparging on hollow fiber membranes in a bubble column reactor.

    Science.gov (United States)

    Xia, Lijun; Law, Adrian Wing-Keung; Fane, Anthony G

    2013-07-01

    Air sparging is now a standard approach to reduce concentration polarization and fouling of membrane modules in membrane bioreactors (MBRs). The hydrodynamic shear stresses, bubble-induced turbulence and cross flows scour the membrane surfaces and help reduce the deposit of foulants onto the membrane surface. However, the detailed quantitative knowledge on the effect of air sparging remains lacking in the literature due to the complex hydrodynamics generated by the gas-liquid flows. To date, there is no valid model that describes the relationship between the membrane fouling performance and the flow hydrodynamics. The present study aims to examine the impact of hydrodynamics induced by air sparging on the membrane fouling mitigation in a quantitative manner. A modelled hollow fiber module was placed in a cylindrical bubble column reactor at different axial heights with the trans-membrane pressure (TMP) monitored under constant flux conditions. The configuration of bubble column without the membrane module immersed was identical to that studied by Gan et al. (2011) using Phase Doppler Anemometry (PDA), to ensure a good quantitative understanding of turbulent flow conditions along the column height. The experimental results showed that the meandering flow regime which exhibits high flow instability at the 0.3 m is more beneficial to fouling alleviation compared with the steady flow circulation regime at the 0.6 m. The filtration tests also confirmed the existence of an optimal superficial air velocity beyond which a further increase is of no significant benefit on the membrane fouling reduction. In addition, the alternate aeration provided by two air stones mounted at the opposite end of the diameter of the bubble column was also studied to investigate the associated flow dynamics and its influence on the membrane filtration performance. It was found that with a proper switching interval and membrane module orientation, the membrane fouling can be effectively

  20. Preparation of activated carbon hollow fibers from ramie at low temperature for electric double-layer capacitor applications.

    Science.gov (United States)

    Du, Xuan; Zhao, Wei; Wang, Yi; Wang, Chengyang; Chen, Mingming; Qi, Tao; Hua, Chao; Ma, Mingguo

    2013-12-01

    Activated carbon hollow fibers (ACHFs) with high surface area were prepared from inexpensive, renewable ramie fibers (RFs) by a single-step activation method under lower temperature than that of other reports. The effects of activation conditions on the pore structure and turbostratic structure of ACHFs were investigated systematically. The results show that ACHFs surface area decreased but micropore volume and conductivity increased as the increase of activation temperature and activation time. The electrochemical measurements of supercapacitors fabricated from these ACHFs electrodes reveal that the electrochemical properties improved with the enhancing of activation degree. However, too high activation temperature can make the ion diffusion resistance increase. It suggests that pore structure and conductivity are as important as surface area to decide the electrochemical performances of ACHFs electrode materials. A maximum capacity of 287 F g(-1) at 50 mA g(-1) was obtained for the ACHFs electrode prepared under suitable conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Highly porous oil sorbent based on hollow fibers as the interceptor for oil on static and running water

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Ting [College of Textiles, Donghua University, Shanghai 201620 (China); Cao, Shengbin [College of Textiles, Donghua University, Shanghai 201620 (China); School of Mechanical Engineering, Shanghai Dianji University, Shanghai 201306 (China); Xu, Guangbiao, E-mail: guangbiao_xu@dhu.edu.cn [College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science and Technology Ministry of Education, Donghua University, Shanghai 201620 (China)

    2016-03-15

    Highlights: • Highly porous sorbent was made up of kapok and PET fibers. • The sorbent was prepared by air-laying-bonding method. • The sorbent showed much higher oil sorption capacity than 100% loose kapok fibers. • The sorbent showed high intercepting efficiency to oils on water. • The runing of water significantly accelerated the oil leakage. - Abstract: Highly porous fibrous assembly made by kapok and hollow PET fibers was prepared by the air-laying-bonding method, and used as the interceptor for oils on static and running water. SEM showed that the vast majority of kapok and PET fibers in the assembly was intact and retained their hollow lumens, with the assembly's porosity high to 98.03%. Oil sorption tests exhibited that kapok/PET assembly could absorb 63.00 g/g of vegetable oil and 58.50 g/g of used motor oil, with high oil retention after 24 h dripping. In static condition of oil interception, the two oils started to leak at around 20 min for 10-mm thick kapok/PET wall. The time for that was prolonged with increasing the thickness of kapok/PET wall. After oil breakthrough, continuous oil leaking took place. The typical leakage was divided into three stages in which oils leaked separately in sharply increased rate, reduced rate and finally gently. In running condition, oils leaked in markedly quicker way than that in static condition, with initial leakage of oils shortened to less 6 min when the water ran at 60.35 ml/s. The leakage of oils was considerably accelerated with increasing running rates.

  2. Preparation of Fiber Based Binder Materials to Enhance the Gas Adsorption Efficiency of Carbon Air Filter.

    Science.gov (United States)

    Lim, Tae Hwan; Choi, Jeong Rak; Lim, Dae Young; Lee, So Hee; Yeo, Sang Young

    2015-10-01

    Fiber binder adapted carbon air filter is prepared to increase gas adsorption efficiency and environmental stability. The filter prevents harmful gases, as well as particle dusts in the air from entering the body when a human inhales. The basic structure of carbon air filter is composed of spunbond/meltblown/activated carbon/bottom substrate. Activated carbons and meltblown layer are adapted to increase gas adsorption and dust filtration efficiency, respectively. Liquid type adhesive is used in the conventional carbon air filter as a binder material between activated carbons and other layers. However, it is thought that the liquid binder is not an ideal material with respect to its bonding strength and liquid flow behavior that reduce gas adsorption efficiency. To overcome these disadvantages, fiber type binder is introduced in our study. It is confirmed that fiber type binder adapted air filter media show higher strip strength, and their gas adsorption efficiencies are measured over 42% during 60 sec. These values are higher than those of conventional filter. Although the differential pressure of fiber binder adapted air filter is relatively high compared to the conventional one, short fibers have a good potential as a binder materials of activated carbon based air filter.

  3. Experimental study on the separation of CO{sub 2} from flue gas using hollow fiber membrane contactors without wetting

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shui-ping; Fang, Meng-Xiang; Zhang, Wei-Feng; Luo, Zhong-Yang; Cen, Ke-Fa [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China); Wang, Shu-Yuan; Xu, Zhi-Kang [Institute of Polymer Science, Zhejiang University, Hangzhou 310027 (China)

    2007-05-15

    Experiments on CO{sub 2} removal from flue gas using polypropylene (PP) hollow fiber membrane contactors were conducted in this study. Absorbents including aqueous potassium glycinate (PG) solution, aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) were used to absorb CO{sub 2} in the experiments. Based on the wetting experimental results, aqueous PG solution can offer a higher surface tension than water, aqueous MEA and MDEA solutions. Aqueous PG solution has a lower potential of membrane wetting after a continuously steady operation for 40 h to maintain CO{sub 2} removal efficiency of about 90%. Under moderate operating conditions, effects of the temperature, flow rate, and concentration of absorbents, and the flow rate of flue gas as well as the volumetric concentration of carbon dioxide in the flue gas on the mass transfer rate of CO{sub 2} were studied on a pilot-scale test facility. Unlike conventional absorbents, the mass transfer decreases with an increasing liquid temperature when using aqueous PG solution. Results show that CO{sub 2} removal efficiency was above 90% and the mass transfer rate was above 2.0 mol/(m{sup 2} h) using the PG aqueous solution. It indicates that the hollow fiber membrane contactor has a great potential in the area of CO{sub 2} separation from flue gas when absorbent's concentration and liquid-gas pressure difference are designed elaborately. (author)

  4. Effect of polymer concentration on the structure and performance of PEI hollow fiber membrane contactor for CO2 stripping.

    Science.gov (United States)

    Naim, R; Ismail, A F

    2013-04-15

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13-16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10(-2)mol/m(2)s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Optimization of CO2 Absorption Characteristic under the Influence of SO2 in Flue Gas by Hollow Fiber Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Ziyi Qu

    2016-01-01

    Full Text Available Hollow fiber membrane contactor is a new, highly efficient, and the most promising technology for CO2 absorption in flue gas. There is still SO2 that exists in the flue gas after desulfurization tower of power plant. This paper studied the influence of SO2 on CO2 absorption characteristic in flue gas by hollow fiber membrane contactor with absorbent of EDA, EDA + MEA (0.6 : 0.4, and EDA + MEA + PZ (0.4 : 0.4 : 0.2. The influences of SO2 concentration, cycle absorption and desorption characteristic of absorbent, absorbent concentration, and liquid-gas flow rate ratio are studied to analyze the influence of SO2 on CO2 absorption characteristic. The appropriate absorbent composition ratio and appropriate parameter range that can inhibit the influence of SO2 are proposed by studying the hybrid sorbent with activating agent, appropriate absorbent concentration, and ratio of liquid-gas flow rate. Among the three kinds of absorbents, EDA + MEA + PZ (0.4 : 0.4 : 0.2 had the best tolerance ability to SO2 and the highest efficiency. With comprehensive consideration of CO2 removal efficiency and operating cost, under the condition of 1000 ppm SO2, the appropriate concentration and liquid-gas flow rate ratio of EDA, EDA + MEA, and EDA + MEA + PZ are proposed.

  6. Rational design of heteropolyacid-based nanosorbent for hollow fiber solid phase microextraction of organophosphorus residues in hair samples.

    Science.gov (United States)

    Ebrahimi, Mahmoud; Es'haghi, Zarrin; Samadi, Fatemeh; Bamoharram, Fatemeh Farrash; Hosseini, Mohammad-Saeid

    2012-02-17

    A novel heteropolyacid-based supported ionic liquid (IL) mediated sol-gel hybrid organic-inorganic material is presented for effective use in hollow fiber solid phase microextraction (HF-SPME). We examined a Keggin-based IL that was evaluated in conjunction with sol-gel. This study shows that Keggin-based IL sol-gel generated porous morphology pro effective extraction media. The method was developed for the extraction of the organophosphorus pesticides (OPs); diazinon, fenitrothion and malathion from human hair samples. The OPs were subsequently analyzed with high performance liquid chromatography and photodiode array detection (HPLC-PDA). In the basic condition (pH 10-11), the gel growth process in the presence of IL was initiated. Afterward, this sol was injected into a polypropylene hollow fiber segment for in situ-gelation process. Parameters affecting the efficiency of HF-SPME were thoroughly investigated. Linearity was observed over a range of 0.02-50,000 μg/g and 0.0001-25,000 ng/mL with detection limits between 0.0074-1.3000 μg/g and 0.00034-0.84 ng/mL for the OPs in hair and aqueous matrices, respectively. The relative recoveries in the real samples, for OPs in the storekeeper hair ranged from 86 to 95.2%. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Gas refractometry based on an all-fiber spatial optical filter.

    Science.gov (United States)

    Silva, Susana; Coelho, L; André, R M; Frazão, O

    2012-08-15

    A spatial optical filter based on splice misalignment between optical fibers with different diameters is proposed for gas refractometry. The sensing head is formed by a 2 mm long optical fiber with 50 μm diameter that is spliced with a strong misalignment between two single-mode fibers (SMF28) and interrogated in transmission. The misalignment causes a Fabry-Perot behavior along the reduced-size fiber and depending on the lead-out SMF28 position, it is possible to obtain different spectral responses, namely, bandpass or band-rejection filters. It is shown that the spatial filter device is highly sensitive to refractive index changes on a nitrogen environment by means of the gas pressure variation. A maximum sensitivity of -1390 nm/RIU for the bandpass filter was achieved. Both devices have shown similar temperature responses with an average sensitivity of 25.7 pm/°C.

  8. A Polarization Maintaining Filter based on a Liquid-Crystal-Photonic-Bandgap-Fiber

    DEFF Research Database (Denmark)

    Scolari, Lara; Olausson, Christina Bjarnal Thulin; Turchinovich, Dmitry

    2008-01-01

    A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm.......A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm....

  9. Gas chromatography-mass spectrometry determination of earthy-musty odorous compounds in waters by two phase hollow-fiber liquid-phase microextraction using polyvinylidene fluoride fibers.

    Science.gov (United States)

    Yu, Shengbing; Xiao, Qin; Zhu, Binghui; Zhong, Xiuhua; Xu, Yinghua; Su, Guangning; Chen, Min

    2014-02-14

    A rapid and sensitive method for the determination of earthy-musty odorous compounds, 2-methylisoborneol, 2-isopropyl-3-methoxy pyrazine, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, and geosmin, in water samples has been developed. The method was based on coupling a new polyvinylidene fluoride (PVDF) hollow-fiber liquid-phase microextraction system with gas chromatography-mass spectrometry (GC-MS). The PVDF hollow fibers have high porosity and an enhanced solvent compatibility for extraction of the target analytes. Experimental conditions were optimized by investigating the type of extraction solvent, sample pH, sodium chloride concentration, stirring speed, extraction time, and GC-MS conditions. Under optimized conditions, the earthy-musty odorous compounds exhibited good linearity (R>0.995) in the concentration range of 6.2-250ng/L. The repeatability and reproducibility of the method were lower than 6.8% and 9.8%, respectively. The limit of detection and limit of quantification values were lower than 2.0 and 6.2ng/L, respectively. The analysis of different water samples such as tap, pond, rive and waste water indicated minimal matrix effects. Analyte recoveries for real samples spiked at different concentrations were between 84.4% and 117.5%. Copyright © 2014. Published by Elsevier B.V.

  10. Distributed Mode Filtering Rod Fiber Amplifier With Improved Mode Stability

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas Tanggaard; Broeng, Jes

    2012-01-01

    We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime.......We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime....

  11. Fiber-reinforced composite hot-gas filters

    Science.gov (United States)

    Stinton, D. P.; Lowden, R. A.; Chang, R.

    1987-05-01

    A chemical vapor deposition process was developed for the fabrication of high-temperature particulate filters. Fibrous materials such as Nicalon (SiC) felt and aluminosilicate papers were used as the filter material. Preliminary evaluation of filter specimens fabricated from Nicalon revealed extremely encouraging results. Cleanable filters with collection efficiencies of greater than 99.9% were recorded for both PFBC flyash and gasifier char.

  12. Investigation on the Effect of Underwater Acoustic Pressure on the Fundamental Mode of Hollow-Core Photonic Bandgap Fibers

    Directory of Open Access Journals (Sweden)

    Adel Abdallah

    2015-01-01

    Full Text Available Recently, microstructured optical fibers have become the subject of extensive research as they can be employed in many civilian and military applications. One of the recent areas of research is to enhance the normalized responsivity (NR to acoustic pressure of the optical fiber hydrophones by replacing the conventional single mode fibers (SMFs with hollow-core photonic bandgap fibers (HC-PBFs. However, this needs further investigation. In order to fully understand the feasibility of using HC-PBFs as acoustic pressure sensors and in underwater communication systems, it is important to study their modal properties in this environment. In this paper, the finite element solver (FES COMSOL Multiphysics is used to study the effect of underwater acoustic pressure on the effective refractive index neff of the fundamental mode and discuss its contribution to NR. Besides, we investigate, for the first time to our knowledge, the effect of underwater acoustic pressure on the effective area Aeff and the numerical aperture (NA of the HC-PBF.

  13. Water reclamation from emulsified oily wastewater via effective forward osmosis hollow fiber membranes under the PRO mode.

    Science.gov (United States)

    Han, Gang; de Wit, Jos S; Chung, Tai-Shung

    2015-09-15

    By using a novel hydrophilic cellulose acetate butyrate (CAB) as the membrane material for the hollow fiber substrate and modifying its outer surface by polydopamine (PDA) coating and inner surface by interfacial polymerization, we have demonstrated that the thin-film composite (TFC) membranes can be effectively used for sustainable water reclamation from emulsified oil/water streams via forward osmosis (FO) under the pressure retarded osmosis (PRO) mode. The newly developed TFC-FO hollow fiber membrane shows characteristics of high water flux, outstanding salt and oil rejection, and low fouling propensity. Under the PRO mode, the newly developed TFC-FO membrane exhibits a water flux of 37.1 L m(-2) h(-1) with an oil rejection of 99.9% using a 2000 ppm soybean oil/water emulsion as the feed and 1 M NaCl as the draw solution. Remarkable anti-fouling behaviors have also been observed. Under the PRO mode, the water flux decline is only 10% of the initial value even after a 12 h test for oil/water separation. The water flux of the fouled membrane can be effectively restored to 97% of the original value by water rinses on the fiber outer surface without using any chemicals. Furthermore, the flux declines are only 25% and 52% when the water recovery of a 2000 ppm soybean oil/water emulsion and a 2000 ppm petroleum oil/water emulsion containing 0.04 M NaCl reaches 82%, respectively. This study may not only provide insightful guidelines for the fabrication of effective TFC-FO membranes with high performance and low fouling behaviors for oily wastewater under the PRO mode but also add an alternative perspective to the design of new materials for water purification purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Application of hollow-fiber-assisted liquid-phase microextraction to identify avermectins in stream water using MS/MS.

    Science.gov (United States)

    Park, Jong-Hyouk; Abd El-Aty, A M; Rahman, Md Musfiqur; Choi, Jeong-Heui; Shim, Jae-Han

    2013-09-01

    In this study, a hollow-fiber-assisted liquid-phase microextraction (HF-LPME) technique coupled with LC-MS/MS is described to detect avermectins (abamectin, ivermectin, moxidectin, and doramectin) in stream water. An Accurel polypropylene membrane was used as the hollow fiber, and dihexyl ether was used as the extraction solvent. The optimal extraction conditions for HF-LPME were 4 cm fiber length, 45 min extraction time, 200 rpm, and 1 min desorption time with methanol as the desorption solvent. The linear range was 0.15-100 ng/mL (r(2) = 0.994-0.998), and the LOD and LOQ were 0.15 and 0.5 ng/mL, respectively. Recovery rates were determined at 1, 5, and 10 ng/mL, and the results were in the range of 80.1 to 93.7%. The intraday and interday repeatability ranged from 2.8 to 8.0% and from 6.1 to 13.3%, respectively. The HF-LPME method developed was applied to detect avermectins in stream water samples collected from 14 different sites near livestock farms located in Honam area, Republic of Korea; however, none of the samples contained avermectin residues. HF-LPME combined with a LC-MS/MS method was successfully applied for an environmentally friendly identification of avermectins in water samples. HF-LPME represents an attractive approach for conventional liquid-liquid extraction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Distributed mode filtering rod fiber amplifier delivering 292W with improved mode stability

    DEFF Research Database (Denmark)

    Laurila, Marko; Jørgensen, Mette Marie; Hansen, Kristian Rymann

    2012-01-01

    We demonstrate a high power fiber (85μm core) amplifier delivering up to 292Watts of average output power using a mode-locked 30ps source at 1032nm. Utilizing a single mode distributed mode filter bandgap rod fiber, we demonstrate 44% power improvement before the threshold-like onset of mode...

  16. Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings.

    Science.gov (United States)

    Mora, J; Andrés, M V; Cruz, J L; Ortega, B; Capmany, J; Pastor, D; Sales, S

    2003-08-01

    We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.

  17. Polymeric THz 2D Photonic Crystal Filters Fabricated by Fiber Drawing

    DEFF Research Database (Denmark)

    Stecher, Matthias; Jansen, Christian; Ahmadi-Boroujeni, Mehdi

    2012-01-01

    In this paper, we report on a new form of polymeric 2D photonic crystal filters for THz frequencies fabricated using a standard fiber drawing technique. The band stop filters were modeled and designed using the generalized multipole technique. The frequency and angle-dependent transmission...

  18. Broad-band robustly single-mode hollow-core PCF by resonant filtering of higher order modes

    CERN Document Server

    Günendi, Mehmet C; Frosz, Michael H; Russell, Philip St J

    2015-01-01

    We propose and theoretically analyse a novel hollow-core photonic crystal fibre (PCF) that is engineered so as to strongly suppress higher order modes, i.e., to provide robust LP$_{01}$ single-mode guidance in all the wavelength ranges where the fibre guides with low loss. Encircling the core is a single ring of non-touching glass elements whose modes are tailored to ensure resonant phase-matched coupling to higher-order core modes, causing them to leak at a very high rate into the supporting solid glass sheath. Using a model based on coupled capillary waveguides, as well as full vectorial finite element modelling, we show that this modal filtering effect depends on only one dimensionless geometrical parameter, akin to the well-known $d/{\\Lambda}$ parameter for endlessly single-mode solid-core PCF. The design is scalable up to large core sizes and is predicted to deliver LP$_{01}$ mode losses of some $10$s of dB/km in multiple transmission windows, the broadest of which spans more than an octave. At the same ...

  19. New 3-dimensional CFD modeling of CO2 and H2S simultaneous stripping from water within PVDF hollow fiber membrane contactor

    Science.gov (United States)

    Bahlake, Ahmad; Farivar, Foad; Dabir, Bahram

    2016-07-01

    In this paper a 3-dimensional modeling of simultaneous stripping of carbon dioxide (CO2) and hydrogen sulfide (H2S) from water using hollow fiber membrane made of polyvinylidene fluoride is developed. The water, containing CO2 and H2S enters to the membrane as feed. At the same time, pure nitrogen flow in the shell side of a shell and tube hollow fiber as the solvent. In the previous methods of modeling hollow fiber membranes just one of the membranes was modeled and the results expand to whole shell and tube system. In this research the whole hollow fiber shell and tube module is modeled to reduce the errors. Simulation results showed that increasing the velocity of solvent flow and decreasing the velocity of the feed are leads to increase in the system yield. However the effect of the feed velocity on the process is likely more than the influence of changing the velocity of the gaseous solvent. In addition H2S stripping has higher yield in comparison with CO2 stripping. This model is compared to the previous modeling methods and shows that the new model is more accurate. Finally, the effect of feed temperature is studied using response surface method and the operating conditions of feed temperature, feed velocity, and solvent velocity is optimized according to synergistic effects. Simulation results show that, in the optimum operating conditions the removal percentage of H2S and CO2 are 27 and 21 % respectively.

  20. Diglycolamide-functionalized calix[4]arene for Am(III) recovery from radioactive wastes: liquid membrane studies using a hollow fiber contactor

    NARCIS (Netherlands)

    Ansari, S.A.; Mohapatra, P.K.; Kandwal, P.; Verboom, Willem

    2016-01-01

    The transport of Am(III) from nitric acid feeds was investigated using hollow fiber supported liquid membrane (HFSLM) containing a diglycolamide-functionalized calix[4]arene (C4DGA) as the carrier extractant. The effect of feed acidity and Nd(III) concentration (used to represent Am(III)) in the

  1. A controlled wet-spinning and dip-coating process for preparation of high-permeable TiO2 hollow fiber membranes.

    Science.gov (United States)

    Zhang, Qi; Wang, Hua; Fan, Xinfei; Chen, Shuo; Yu, Hongtao; Quan, Xie

    2016-01-01

    In order to improve the permeate flux of photocatalytic membranes, we present an approach for coupling TiO2 with ceramic hollow fiber membranes. The ceramic hollow fiber membranes with high permeate flux were fabricated by a controlled wet-spinning process using polyethersulfone (PESf) and ceramic powder as precursors and 1-methyl-2-pyrrolidinone as solvent, and the subsequent TiO2 coating was performed by a dip-coating process using tetra-n-butyl titanate as precursor. It has been found that the PESf/ceramic powder ratio could influence the structure of the membranes. Here the as-prepared TiO2 hollow fiber membranes had a pure water flux of 4,450 L/(m(2)·h). The performance of the TiO2 hollow fiber membrane was evaluated using humic acid (HA) as a test substance. The results demonstrated that this membrane exhibited a higher permeate flux under UV irradiation than in the dark and the HA removal efficiency was enhanced. The approach described here provides an operable route to the development of high-permeable photocatalytic membranes for water treatment.

  2. Characterization of morphology controlled polyethersulfone hollow fiber membranes by the addition of polyethylene glycol to the dope and bore liquid solution

    NARCIS (Netherlands)

    Koops, G.H.; Liu, Y.; Liu, Y.; Strathmann, H.

    2003-01-01

    The preparation of polyethersulfone (PES) hollow fiber membranes has been studied using N-methylpyrrolidone (NMP) as solvent, polyethylene glycol 400 (PEG 400) as weak nonsolvent and water as strong nonsolvent. When PEG 400 is used as polymeric additive to the spinning dope the viscosity of the PES

  3. A Microfiltration Polymer-Based Hollow-Fiber Cathode as a Promising Advanced Material for Simultaneous Recovery of Energy and Water

    KAUST Repository

    Katuri, Krishna

    2016-09-12

    A novel electrocatalytic and microfiltration polymeric hollow fiber is fabricated for simultaneous recovery of energy (H2) and clean fresh water from wastewater, hence addressing two grand challenges facing society in the current century (i.e., providing adequate supplies of clean fresh water and energy as the world\\'s population increases).

  4. Characteristics of 1.9-μm laser emission from hydrogen-filled hollow-core fiber by vibrational stimulated Raman scattering

    Science.gov (United States)

    Gu, Bo; Chen, Yubin; Wang, Zefeng

    2016-12-01

    We report here the characteristics of 1.9-μm laser emission from a gas-filled hollow-core fiber by stimulated Raman scattering (SRS). A 6.5-m hydrogen-filled ice-cream negative curvature hollow-core fiber is pumped with a high peak-power, narrow linewidth, linearly polarized subnanosecond pulsed 1064-nm microchip laser, generating a pulsed vibrational Stokes wave at 1908.5 nm. The maximum quantum efficiency of about 48% is obtained, which is mainly limited by the mode mismatch between the pump laser beam and the Stokes wave in the hollow-core fiber. The linewidths of the pump laser and the first-order vibrational Stokes wave are measured to be about 1 and 2 GHz, respectively, by a scanning Fabry-Perot interferometer. The pressure selection phenomenon of the vibrational anti-Stokes waves is also investigated. The pulse duration of the vibrational Stokes wave is recorded to be narrower than that of the pump laser. The polarization properties of the hollow-core fiber and the polarization dependence of the vibrational and the rotational SRS are also studied. The beam profile of the vibrational Stokes wave shows good quality.

  5. SiO2/ZnO Composite Hollow Sub-Micron Fibers: Fabrication from Facile Single Capillary Electrospinning and Their Photoluminescence Properties.

    Science.gov (United States)

    Song, Guanying; Li, Zhenjiang; Li, Kaihua; Zhang, Lina; Meng, Alan

    2017-02-24

    In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS), polyvinylpyrrolidone (PVP) and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO. The products revealed uniform tubular structure with outer diameters of 400-500 nm and wall thickness of 50-60 nm. The gases generated and the directional escaped mechanism was proposed to illustrate the formation of SiO2/ZnO composite hollow sub-micron fibers. Furthermore, a broad blue emission band was observed in the photoluminescence (PL) of SiO2/ZnO composite hollow sub-micron fibers, exhibiting great potential applications as blue light-emitting candidate materials.

  6. SiO2/ZnO Composite Hollow Sub-Micron Fibers: Fabrication from Facile Single Capillary Electrospinning and Their Photoluminescence Properties

    Directory of Open Access Journals (Sweden)

    Guanying Song

    2017-02-01

    Full Text Available In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS, polyvinylpyrrolidone (PVP and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FT-IR spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO. The products revealed uniform tubular structure with outer diameters of 400–500 nm and wall thickness of 50–60 nm. The gases generated and the directional escaped mechanism was proposed to illustrate the formation of SiO2/ZnO composite hollow sub-micron fibers. Furthermore, a broad blue emission band was observed in the photoluminescence (PL of SiO2/ZnO composite hollow sub-micron fibers, exhibiting great potential applications as blue light-emitting candidate materials.

  7. Hollow fiber membrane contactors for CO2 capture: modeling and up-scaling to CO2 capture for an 800 MWe coal power station

    NARCIS (Netherlands)

    Kimball, E.; Al-Azki, A.; Gomez, A.; Goetheer, E.L.V.; Booth, N.; Adams, D.; Ferre, D.

    2014-01-01

    A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM) with the more conventional structured packing columns as the absorber in amine-based CO2capture systems for power plants. In order to simulate the operation of industrial scale HFMMsystems, a

  8. Effect of spinning conditions on the structure and the gas permeation properties of high flux polyethersulfone-polyimide blend hollow fibers

    NARCIS (Netherlands)

    Kapantaidakis, G.; Koops, G.H.; Wessling, Matthias

    2002-01-01

    In this work, the effects of major spinning parameters, such as: polymer concentration, air gap distance, bore fluid composition, and take-up velocity on the structure and the permeation properties of polyethersulfone-polyimide gas separation hollow fibers are discussed in detail. It is shown that a

  9. CO2 Absorption from Its Mixture with CH4 or N2 through Hollow Fiber Membrane Contactor using Water as Solvent

    Directory of Open Access Journals (Sweden)

    Sutrasno Kartohardjono

    2010-10-01

    Full Text Available Hollow fiber membrane contactors have been widely used as gas-liquid contactors recently such as in the CO2 absorption process from gas stream. This research aims to evaluate the effectiveness of hollow fiber membrane contactor to absorb CO2 from its mixture with CH4 or N2 using water through mass transfer and hydrodynamic tests. There are 3 membrane modules used in this research with shell diameter of 1.9 cm, length of 40 cm, outer fiber diameter of 2.7 mm and fiber number in the contactors of 10, 15 and 20. Liquid flow rates in the hollow fiber membrane contactors are varied in this research. Research results show that mass transfer coefficients in the membrane contactor increase with increasing liquid flow rate and decrease with increasing fiber number in the contactor. Flux of CO2 into water can achieve 1.4x10-9 mol CO2 /m2.s and mass transfer coefficients can achieve 1.23 x 10-7 m/s. Meanwhile, hydrodynamic test results show that water pressure drop in the membrane contactors increase with increasing fibernumber in the contactors.

  10. Frequency stabilization of a 2.05 μm laser using hollow-core fiber CO2 frequency reference cell

    Science.gov (United States)

    Meras, Patrick; Poberezhskiy, Ilya Y.; Chang, Daniel H.; Spiers, Gary D.

    2010-04-01

    We have designed and built a hollow-core fiber frequency reference cell, filled it with CO2, and used it to demonstrate frequency stabilization of a 2.05 μm Tm:Ho:YLF laser using frequency modulation (FM) spectroscopy technique. The frequency reference cell is housed in a compact and robust hermetic package that contains a several meter long hollow-core photonic crystal fiber optically coupled to index-guiding fibers with a fusion splice on one end and a mechanical splice on the other end. The package has connectorized fiber pigtails and a valve used to evacuate, refill it, or adjust the gas pressure. We have demonstrated laser frequency standard deviation decreasing from >450MHz (free-running) to laser wavelength is of particular interest for spectroscopic instruments due to the presence of many CO2 and H20 absorption lines in its vicinity. To our knowledge, this is the first reported demonstration of laser frequency stabilization at this wavelength using a hollow-core fiber reference cell. This approach enables all-fiber implementation of the optical portion of laser frequency stabilization system, thus making it dramatically more lightweight, compact, and robust than the traditional free-space version that utilizes glass or metal gas cells. It can also provide much longer interaction length of light with gas and does not require any alignment. The demonstrated frequency reference cell is particularly attractive for use in aircraft and space coherent lidar instruments for measuring atmospheric CO2 profile.

  11. In-situ integration of microbial fuel cell with hollow-fiber membrane bioreactor for wastewater treatment and membrane fouling mitigation.

    Science.gov (United States)

    Tian, Yu; Li, Hui; Li, Lipin; Su, Xinying; Lu, Yaobin; Zuo, Wei; Zhang, Jun

    2015-02-15

    A hollow-fiber membrane bioreactor was integrated with a microbial fuel cell to develop a novel system of MFC-MBR based on the utilization of electricity recovered by the MFC for wastewater treatment improvement and membrane fouling mitigation in the MBR. In this system, a maximum power density of 2.18 W/m(3) and an average voltage output of 0.15 V were achieved at an external resistance of 50 Ω. The removal efficiencies of COD, ammonia nitrogen ( [Formula: see text] ) and total nitrogen (TN) in the MFC-MBR were improved by 4.4%, 1.2% and 10.3%, respectively. It is worth noting that, in addition to reducing the deposition of sludge on the membrane surface by the electric field force, the MFC-MBR also alleviated the membrane fouling by sludge modification. Compared with the control MBR (C-MBR), less loosely bound extracellular polymeric substances (LB-EPS), lower SMPp/SMPc ratio, more homogenized sludge flocs and less filamentous bacteria were obtained in the MFC-MBR, which improved the dewaterability and filterability of the sludge. The cake layer on the membrane formed by the modified sludge was more porous with lower compressibility, significantly enhancing the membrane filterability. A proof of concept of an MFC-MBR was provided and shown to be effective in membrane fouling mitigation with efficient wastewater treatment and energy recovery, demonstrating the feasibility of the minute electricity generated by the MFC for membrane fouling alleviation in the MBR. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. The development of a high-throughput measurement method of octanol/water distribution coefficient based on hollow fiber membrane solvent microextraction technique.

    Science.gov (United States)

    Bao, James J; Liu, Xiaojing; Zhang, Yong; Li, Youxin

    2014-09-15

    This paper describes the development of a novel high-throughput hollow fiber membrane solvent microextraction technique for the simultaneous measurement of the octanol/water distribution coefficient (logD) for organic compounds such as drugs. The method is based on a designed system, which consists of a 96-well plate modified with 96 hollow fiber membrane tubes and a matching lid with 96 center holes and 96 side holes distributing in 96 grids. Each center hole was glued with a sealed on one end hollow fiber membrane tube, which is used to separate the aqueous phase from the octanol phase. A needle, such as microsyringe or automatic sampler, can be directly inserted into the membrane tube to deposit octanol as the accepted phase or take out the mixture of the octanol and the drug. Each side hole is filled with aqueous phase and could freely take in/out solvent as the donor phase from the outside of the hollow fiber membranes. The logD can be calculated by measuring the drug concentration in each phase after extraction equilibrium. After a comprehensive comparison, the polytetrafluoroethylene hollow fiber with the thickness of 210 μm, an extraction time of 300 min, a temperature of 25 °C and atmospheric pressure without stirring are selected for the high throughput measurement. The correlation coefficient of the linear fit of the logD values of five drugs determined by our system to reference values is 0.9954, showed a nice accurate. The -8.9% intra-day and -4.4% inter-day precision of logD for metronidazole indicates a good precision. In addition, the logD values of eight drugs were simultaneously and successfully measured, which indicated that the 96 throughput measure method of logD value was accurate, precise, reliable and useful for high throughput screening. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Development of a novel hollow-fiber liquid-phase microextraction based on oil-in-salt and its comparison with conventional one.

    Science.gov (United States)

    Li, Miao-Miao; Hu, Shuang; Chen, Xuan; Bai, Xiao-Hong

    2017-07-01

    A novel hollow-fiber liquid-phase microextraction based on oil-in-salt was proposed and introduced for the simultaneous extraction and enrichment of the main active compounds of hesperidin, honokiol, shikonin, magnolol, emodin, and β,β'-dimethylacrylshikonin in a formula of Zi-Cao-Cheng-Qi decoction and the single herb, Fructus Aurantii Immaturus, Cortex Magnoliae Officinalis, Radix et Rhizoma, and Lithospermum erythrorhizon, composing the formula prior to their analysis by high-performance liquid chromatography. The results obtained by the proposed procedure were compared with those obtained by conventional hollow-fiber liquid-phase microextraction, and the proposed procedure mechanism was described. In the procedure, a hollow-fiber segment was first immersed in organic solvent to fill the solvent in the fiber lumen and wall pore, and then the fiber was again immersed into sodium chloride solution to cover a thin salt membrane on the fiber wall pore filling organic solvent. Under the optimum conditions, the enrichment factors of the analytes were 0.6-109.4, linearities were 0.002-12 μg/mL with r2  ≥ 0.9950, detection limits were 0.6-12 ng/mL, respectively. The results showed that oil-in-salt hollow-fiber liquid-phase microextraction is a simple and effective sample pretreatment procedure and suitable for the simultaneous extraction and concentration of trace-level active compounds in traditional Chinese medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Application of β-cyclodextrin-modified, carbon nanotube-reinforced hollow fiber to solid-phase microextraction of plant hormones.

    Science.gov (United States)

    Song, Xin-Yue; Ha, Wei; Chen, Juan; Shi, Yan-Ping

    2014-12-29

    A new, efficient, and environmental friendly solid-phase microextraction (SPME) medium based on β-cyclodextrin (β-CD)-modified carbon nanotubes (CNTs) and a hollow fiber (HF) was prepared. Functionalized β-CD was covalently linked to the surface of the carboxylic CNTs and then the obtained nanocomposite was immobilized into the wall pores of HFs under ultrasonic-assisted effect. The scanning electron microscope was used to inspect surface characteristics of fibers, demonstrating the presence of nanocomposites in their wall pores. The reinforced HF was employed in SPME, and its extraction performance was evaluated by analyzing 1-naphthaleneacetic acid (NAA) and 2-naphthoxyacetic acid (2-NOA) in vegetables. Without any tedious clean-up procedure, analytes were extracted from the sample to the adsorbent and organic solvent immobilized in HFs and then desorbed in acetonitrile prior to chromatographic analysis. Under the optimized extraction conditions, the method provided 275- and 283-fold enrichment factors of NAA and 2-NOA, low limits of detection and quantification (at an ngg(-1) level), satisfactory spiked recoveries, good inter-fiber repeatability, and batch-to-batch reproducibility. The selectivity of the developed fiber was investigated to three structurally similar compounds and two reference compounds with recognition coefficients up to 3.18. The obtained results indicate that the newly developed fiber is a feasible, selective, green, and cost-effective microextraction medium and could be successfully applied for extraction and determination of naphthalene-derived plant hormones in complex matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Highly efficient high power single-mode fiber amplifier utilizing the distributed mode filtering bandgap rod fiber

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas T.; Jørgensen, Mette Marie

    2012-01-01

    We report on an ytterbium doped single mode distributed mode filtering rod fiber in an amplifier configuration delivering high average output power, up to 292 watts, using a mode-locked 30ps source at 1032nm with good power conversion efficiency. We study the modal stability of the output beam...... at high average output power levels and demonstrate a 44% power improvement before the threshold-like onset of mode instabilities by operating the rod fiber in a leaky waveguide regime. We investigate the guiding dynamics of the rod fiber and explain the improved performance by thermally induced...

  16. Influence of a preadsorbed terpolymer on human platelet accumulation, fibrinogen adsorption, and ex vivo blood activation in hemodialysis hollow fibers.

    Science.gov (United States)

    Yan, F; Déjardin, P; Mulvihill, J N; Cazenave, J P; Crost, T; Thomas, M; Pusineri, C

    1992-01-01

    Results are presented on kinetics of platelet accumulation in charged polyacrylonitrile (AN69) hollow fibers by continuous data recording under flow conditions (wall shear rate 108-1050 s-1), using suspensions of washed 111In-labeled human platelets in Tyrode's-albumin buffer, containing washed red blood cells (0-40%). Preadsorption of a terpolymer of acrylonitrile, poly(ethyleneoxide) methacrylate and trimethylaminoethyl chloride methacrylate leads to very efficient passivation with respect to platelet accumulation and fibrinogen adsorption. In human ex vivo tests, evaluation of complement peptide C3a, platelet beta-thromboglobulin, leucocyte-polymorphonuclear neutrophile elastase and fibrinopeptide A shows no detectable activation. Furthermore, preadsorption appears to result in simultaneous improvement in hemocompatibility of the blood lines leading to and from the dialysis module. This single pretreatment of dialysis membranes should allow injection of lower doses of anticoagulant to patients submitted to hemodialysis.

  17. Analyzing the effect of carbon fiber reinforced polymer on the crashworthiness of aluminum square hollow beam for crash box application

    Science.gov (United States)

    Raman, R.; Jayanth, K.; Sarkar, I.; Ravi, K.

    2017-11-01

    Crashworthiness of a material is a measure of its ability to absorb energy during a crash. A well-designed crash box is instrumental in protecting the costly vehicle components. A square, hollow, hybrid beam of aluminum/CFRP was subjected to dynamic axial load to analyze the effect of five different lay-up sequences on its crashworthiness. The beam was placed between two plates. Boundary conditions were imposed on them to simulate a frontal body crash test model. Modeling and dynamic analysis of composite structures was done on ABAQUS. Different orientation of carbon fibers varies the crashworthiness of the hybrid beam. Addition of CFRP layer showed clear improvement in specific energy absorption and crush force efficiency compared to pure aluminum beam. Two layers of CFRP oriented at 90° on Aluminum showed 52% increase in CFE.

  18. Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: I. Theoretical simulation and verification.

    Science.gov (United States)

    Wu, Qian; Wu, Dapeng; Geng, Xuhui; Shen, Zheng; Guan, Yafeng

    2012-07-27

    Osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) was validated and utilized to improve enrichment factor of extraction in this study. When donor phase (sample solution) with higher ion strength than acceptor phase (extraction phase) was used, osmosis was established from acceptor phase, through organic membrane to donor phase. The mass flux expression of analytes across the organic membrane was established based on the convective-diffusive kinetic model, and the kinetic process for HF-LLLME with osmosis was simulated. Simulation results indicated that osmosis from acceptor phase to donor phase can increase enrichment factor of HF-LLLME, accelerate extraction process, and even result in the distribution ratio of analytes between donor and acceptor phase exceeding their partition coefficient. This phenomenon was verified by the experimental data of extraction with six organic acids and four organic bases as the model analytes. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Carbon nanotubes reinforced hollow fiber solid phase microextraction for the determination of strychnine and brucine in urine.

    Science.gov (United States)

    Song, Xin-Yue; Shi, Yan-Ping; Chen, Juan

    2013-11-15

    A mixed matrix membrane (MMM), based on carbon nanotubes (CNTs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine strychnine and brucine in urine. This MMM was prepared by dispersing CNTs in water via surfactant assistance, and then immobilizing CNTs into the pores of HF by capillary forces and sonification. The prepared carbon nanotubes reinforced hollow fiber (CNTs-HF) was subsequently wetted by a few microliters of organic solvent (1-octanol), and then applied to extract the target analytes in direct immersion sampling mode. After extraction, analytes were desorbed via ultrasonic-assisted effect, and then detected via high-performance liquid chromatography (HPLC). To achieve the highest extraction efficiency, main extraction parameters such as the type and amount of surfactant, the diameter and doping level of CNTs, extraction time, desorption condition, pH value, stirring rate and volume of the donor phase were optimized. Under the optimum extraction conditions, the method showed good linearity ranges with correlation coefficients higher than 0.9990, good repeatability and batch-to-batch reproducibility with relative standard deviations (RSDs) less than 6% and 5% for strychnine and brucine, respectively, and low limits of detection (0.7 and 0.9 µg L(-1) for strychnine and brucine, respectively). The recoveries were in the range of 83.81-116.14% at three spiked levels. The developed method was successfully applied to real urine sample with mean relative recoveries of 94.28% and 91.30% for strychnine and brucine, respectively. The developed method shows comparable results against reference methods and is a simple, green, and cost-effective microextraction technique. © 2013 Elsevier B.V. All rights reserved.

  20. Effects of dope extrusion rate on the morphology and gas separation performance of asymmetric polysulfone hollow fiber membranes for O2/N2 separation

    Directory of Open Access Journals (Sweden)

    Ahmad Fausi Ismail

    2002-11-01

    Full Text Available The objective of this study was to investigate the influence of dope extrusion rates on morphology and gas separation performance of asymmetric polysulfone hollow fiber membranes. Asymmetric polysulfone hollow fiber membranes for gas separation were prepared from a solution consisting of 26.0 wt. % of polysulfone, 30.4 wt. % of N, N-dimethylacetamide, 30.4 wt. % of tetrahydrofuran and 13.2 wt. % ethanol. The dry/wet phase separation process was applied to a dry/wet spinning process. Fibers were spun at various dope extrusion rates (DER ranging from 1.5 - 3.0 cm3/min and hence at different levels of shear. The results suggest that as the dope extrusion rate is increased, the selectivity will increase until a critical level of shear is reached, beyond which the membrane performance deteriorates. Pressure-normalized-fluxes and selectivities were evaluated by using pure oxygen and nitrogen as test gases.

  1. Noise filtering in a multi-channel system using a tunable liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Scolari, Lara; Tokle, Torger

    2008-01-01

    This paper reports on the first application of a liquid crystal infiltrated photonic bandgap fiber used as a tunable filter in an optical transmission system. The device allows low-cost amplified spontaneous emission (ASE) noise filtering and gain equalization with low insertion loss and broad...... tunability. System experiments show that the use of this filter increases for times the distance over which the optical signal-to-noise ratio (OSNR) is sufficient for error-free transmission with respect to the case in which no filtering is used....

  2. A Gas Cell Based on Hollow-Core Photonic Crystal Fiber (PCF and Its Application for the Detection of Greenhouse Gas (GHG: Nitrous Oxide (N2O

    Directory of Open Access Journals (Sweden)

    Jonas K. Valiunas

    2016-01-01

    Full Text Available The authors report the detection of nitrous oxide gas using intracavity fiber laser absorption spectroscopy. A gas cell based on a hollow-core photonic crystal fiber was constructed and used inside a fiber ring laser cavity as an intracavity gas cell. The fiber laser in the 1.55 μm band was developed using a polarization-maintaining erbium-doped fiber as the gain medium. The wavelength of the laser was selected by a fiber Bragg grating (FBG, and it matches one of the absorption lines of the gas under investigation. The laser wavelength contained multilongitudinal modes, which increases the sensitivity of the detection system. N2O gas has overtones of the fundamental absorption bands and rovibrational transitions in the 1.55 μm band. The system was operated at room temperature and was capable of detecting nitrous oxide gas at sub-ppmv concentration level.

  3. Hydrodynamic Study of a Hollow Fiber Membrane System Using Experimental and Numerical Derived Surface Shear Stresses

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Hunze, M.; Nopens, I.

    2012-01-01

    th percentile) and not the movement of fibers. The latter is likely due to shielding effects or fiber sway, significantly affecting shear stresses at the high end of the distribution. However, this was not accounted for in the model in this study. Despite these deviations, the CFD model in its...

  4. Leakage-free, guidance of light in hollow core optical fibers

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou; Broeng, Jes; Bjarklev, Anders Overgaard

    2000-01-01

    Summary form only given. Despite their tremendous success optical fibers of today are limited by the laws of total internal reflection. During the past five years, however, it has become increasingly evident, that a new operational principle of optical fibers is possible, namely guidance due...

  5. Hollow mesoporous carbon spheres-based fiber coating for solid-phase microextraction of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Hu, Xingru; Liu, Chao; Li, Jiansheng; Luo, Rui; Jiang, Hui; Sun, Xiuyun; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

    2017-10-20

    In this study, a novel hollow mesoporous carbon spheres-based fiber (HMCSs-F) was fabricated to immobilize HMCSs onto a stainless steel wire for solid-phase microextraction (SPME). Characterization results showed that the HMCSs-F possessed a large specific surface area, high porosity and uniform pore size. To demonstrate the extraction performance, a series of polycyclic aromatic hydrocarbons (PAHs) was chosen as target analytes. The experimental parameters including extraction and desorption conditions were optimized. Compared to commercial fibers, the HMCSs-F exhibited better extraction efficiency for PAHs. More interestingly, a good extraction selectivity for PAHs from the complex matrix was observed in these HMCSs-F. The enhanced SPME performance was attributed to the unique pore structure and special surface properties of the HMCSs. Furthermore, under the optimum conditions, the limits of detection (LODs) for the HMCSs-F were in the range of 0.20-1.15ngL-1 with a corresponding relative standard deviation that was below 8.6%. The method was successfully applied for the analysis of PAHs in actual environmental water samples with recoveries ranging from 85.9% to 112.2%. These results imply that the novel HMCSs-F have potential application in environmental water analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Broadband, Lensless and Optomechanically Stabilised Coupling into Microfluidic Hollow-Core Photonic Crystal Fiber Using Glass Nanospike

    CERN Document Server

    Zeltner, Richard; Pennetta, Riccardo; Russell, Philip St J

    2016-01-01

    We report a novel technique for launching broadband laser light into liquid-filled hollow-core photonic crystal fiber (HC-PCF). It uniquely offers self-alignment and self-stabilization via optomechanical trapping of a fused silica nanospike, fabricated by thermally tapering and chemically etching a single mode fiber into a tip diameter of 350 nm. We show that a trapping laser, delivering ~300 mW at 1064 nm, can be used to optically align and stably maintain the nanospike at the core center. Once this is done, a broadband supercontinuum beam (~575 to 1064 nm) can be efficiently and close to achromatically launched in the HC-PCF. The system is robust against liquid-flow in either direction inside the HC-PCF and the Fresnel back-reflections are reduced to negligible levels compared to free-space launching or butt-coupling. The results are of potential relevance for any application where the efficient delivery of broadband light into liquid-core waveguides is desired.

  7. The Fabrication of Ga2O3/ZSM-5 Hollow Fibers for Efficient Catalytic Conversion of n-Butane into Light Olefins and Aromatics

    Directory of Open Access Journals (Sweden)

    Jing Han

    2016-01-01

    Full Text Available In this study, the dehydrogenation component of Ga2O3 was introduced into ZSM-5 nanocrystals to prepare Ga2O3/ZSM-5 hollow fiber-based bifunctional catalysts. The physicochemical features of as-prepared catalysts were characterized by means of XRD, BET, SEM, STEM, NH3-TPD, etc., and their performances for the catalytic conversion of n-butane to produce light olefins and aromatics were investigated. The results indicated that a very small amount of gallium can cause a marked enhancement in the catalytic activity of ZSM-5 because of the synergistic effect of the dehydrogenation and aromatization properties of Ga2O3 and the cracking function of ZSM-5. Compared with Ga2O3/ZSM-5 nanoparticles, the unique hierarchical macro-meso-microporosity of the as-prepared hollow fibers can effectively enlarge the bifunctionality by enhancing the accessibility of active sites and the diffusion. Consequently, Ga2O3/ZSM-5 hollow fibers show excellent catalytic conversion of n-butane, with the highest yield of light olefins plus aromatics at 600 °C by 87.6%, which is 56.3%, 24.6%, and 13.3% higher than that of ZSM-5, ZSM-5 zeolite fibers, and Ga2O3/ZSM-5, respectively.

  8. Design of multichannel DWDM fiber Bragg grating filters by Lagrange multiplier constrained optimization.

    Science.gov (United States)

    Lee, Cheng-Ling; Lee, Ray-Kuang; Kao, Yee-Mou

    2006-11-13

    We present the synthesis of multi-channel fiber Bragg grating (MCFBG) filters for dense wavelength-division-multiplexing (DWDM) application by using a simple optimization approach based on a Lagrange multiplier optimization (LMO) method. We demonstrate for the first time that the LMO method can be used to constrain various parameters of the designed MCFBG filters for practical application demands and fabrication requirements. The designed filters have a number of merits, i.e., flat-top and low dispersion spectral response as well as single stage. Above all, the maximum amplitude of the index modulation profiles of the designed MCFBGs can be substantially reduced under the applied constrained condition. The simulation results demonstrate that the LMO algorithm can provide a potential alternative for complex fiber grating filter design problems.

  9. High-birefringence photonic crystal fiber polarization filter based on surface plasmon resonance.

    Science.gov (United States)

    An, Guowen; Li, Shuguang; Yan, Xin; Yuan, Zhenyu; Zhang, Xuenan

    2016-02-20

    In this paper, we designed a C2v-symmetry-structured photonic crystal fiber with triangular lattice and Au-filled air holes. The finite element method is used to analyze the dispersion and confinement loss characteristics of the core mode and the surface plasmon mode of the metal wire. In this work, we found that the positions of resonance peaks and the resonance strength of core mode and surface plasmon mode can be well adjusted by changing the pitch between the cladding air holes and the diameters of the air holes or metal wires around the core. By optimizing the parameters of the fiber structure, a polarization filter at the communication band is designed. At the wavelength of 1.31 μm, which is located in the communication band, the fundamental mode in X pol can be filtered with the diameter of the metal wire d(m)=1.2  μm. When d(m)=1.4  μm, the fundamental mode in Y pol can be filtered at the wavelength of 1.55 μm, which is also located in the communication band. Compared with the ordinary single-polarization and single-mode photonic crystal fiber, the fiber we proposed in this paper can selectively filter out the polarized light in one direction by adjusting the wire diameter. It is meaningful for the development of the polarization filter in the communication band.

  10. Optimizing single mode robustness of the distributed modal filtering rod fiber amplifier

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Petersen, Sidsel Rübner; Laurila, Marko

    2012-01-01

    from the outer fiber diameter. However, achieving ultra low NA for single mode (SM) guidance is challenging, thus different design strategies must be applied. The distributed modal filtering (DMF) design enables SM guidance in ultra low NA fibers with very large cores, where large preform tolerances...... a large fraction of the Yb emission band including wavelengths of 1030 nm and 1064 nm. Design parameters tolerating refractive index fabrication uncertainties of ± 10-4 are targeted to yield stable SM bandwidths....

  11. Experimental demonstration of passive coherent combining of fiber lasers by phase contrast filtering.

    Science.gov (United States)

    Jeux, François; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Barthelemy, Alain

    2012-12-17

    We report experiments on a new laser architecture involving phase contrast filtering to coherently combine an array of fiber lasers. We demonstrate that the new technique yields a more stable phase-locking than standard methods using only amplitude filtering. A spectral analysis of the output beams shows that the new scheme generates more resonant frequencies common to the coupled lasers. This property can enhance the combining efficiency when the number of lasers to be coupled is large.

  12. Electrically tunable bandpass filter using solid-core photonic crystal fibers filled with multiple liquid crystals

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2010-01-01

    An electrically tunable bandpass filter is designed and fabricated by integrating two solid-core photonic crystal fibers filled with different liquid crystals in a double silicon v-groove assembly. By separately controlling the driving voltage of each liquid-crystal-filled section, both the short......-wavelength edge and the long-wavelength edge of the bandpass filter are tuned individually or simultaneously with the response time in the millisecond range....

  13. Latest developments on fibered MOPA in mJ range with hollow-core fiber beam delivery and fiber beam shaping used as seeder for large scale laser facilities (Conference Presentation)

    Science.gov (United States)

    Gleyze, Jean-François; Scol, Florent; Perrin, Arnaud; Gouriou, Pierre; Valentin, Constance; Bouwmans, Géraud; Hugonnot, Emmanuel

    2017-05-01

    The Laser Megajoule (LMJ) is a French large scale laser facility dedicated to inertial fusion and plasma physics research. LMJ front-ends are based on fiber laser technology at nanojoule range [1]. Scaling the energy of those fiber seeders to the millijoule range is a way to upgrade LMJ's front ends architecture and could also be used as seeder for lasers for ELI project for example. However, required performances are so restrictive (optical-signal-to-noise ratio higher than 50 dB, temporally-shaped nanosecond pulses and spatial single-mode top-hat beam output) that such fiber systems are very tricky to build. High-energy fiber amplifiers In 2015, we have demonstrated, an all-fiber MOPA prototype able to produce a millijoule seeder, but unfortunately not 100% conform for all LMJ's performances. A major difficulty was to manage the frequency modulation used to avoid stimulated Brillouin scattering, to amplitude modulation (FM-AM) conversion, this limits the energy at 170µJ. For upgrading the energy to the millijoule range, it's necessary to use an amplifier with a larger core fiber. However, this fiber must still be flexible; polarization maintaining and exhibit a strictly single-mode behaviour. We are thus developing a new amplifier architecture based on an Yb-doped tapered fiber: its core diameter is from a narrow input to a wide output (MFD 8 to 26 µm). A S² measurement on a 2,5m long tapered fiber rolled-up on 22 cm diameter confirmed that this original geometry allows obtaining strictly single-mode behaviour. In a 1 kHz repetition rate regime, we already obtain 750 µJ pulses, and we are on the way to mJ, respecting LMJ performances. Beam delivery In LMJ architecture the distance between the nanojoule fiber seeder and the amplifier stages is about 16 m. Beam delivery is achieved with a standard PM fiber, such a solution is no longer achievable with hundreds of kilowatt peak powers. An efficient way to minimize nonlinear effects is to use hollow-core (HC

  14. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry

    Science.gov (United States)

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-01

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r2 = 0.998) in the range of 3.0-85.0 μg L-1 with a detection limit of 0.7 μg L-1 for preconcentration of 25.0 mL of the sample and the relative standard deviation (n = 6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments.

  15. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry.

    Science.gov (United States)

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-05

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r(2)=0.998) in the range of 3.0-85.0 μg L(-1) with a detection limit of 0.7 μg L(-1) for preconcentration of 25.0 mL of the sample and the relative standard deviation (n=6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Pre-concentration and determination of zinc in water samples by ligand assisted pseudo stirbar hollow fiber solid/liquid phase microextraction

    Directory of Open Access Journals (Sweden)

    Zarrin Es’haghi

    2017-05-01

    Full Text Available Pre-concentration and determination of Zn (II across a ligand assisted pseudo stirbar hollow fiber solid/liquid phase microextraction method in water samples has been investigated. All detections were carried out by differential pulse anodic stripping voltammetry (DPASV. The method involves microextraction and pre-concentration of Zn (II on the pseudo stir bar hollow fiber. Then desorption has been done using suitable solvent containing suitable ligand as complexing agent. The optimized conditions were obtained. The relationship between the peak current and concentration was linear over the range of 0.05–500 ng mL−1. The limit of detection was 0.015 ng mL−1. Under the optimized conditions, the pre-concentration factor is 5140. The applicability of the developed technique was evaluated by application to spiked, environmental water samples.

  17. Maghemite nanoparticle-decorated hollow fiber electromembrane extraction combined with dispersive liquid-liquid microextraction for the determination of thymol from Carum copticum

    DEFF Research Database (Denmark)

    Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Bohlooli, Mousa

    2017-01-01

    BACKGROUND A novel technique using maghemite nanoparticle-decorated hollow fibers to assist electromembrane extraction is proposed. Electromembrane extraction combined with dispersive liquid–liquid microextraction (EME-DLLME) was applied for the extraction of thymol from Carum copticum, followed...... by gas chromatography with flame ionization detection (GC-FID). RESULTS The use of maghemite nanoparticle-decorated hollow fibers was found to improve the extraction efficiency of thymol significantly. Important operational parameters, including pH of acceptor phase, extraction time, voltage.......2% respectively. The intra- and inter-day accuracy was higher than 93.6%. CONCLUSION The results indicated that EME-DLLME/GC-FID is a useful technique for the extraction and determination of thymol in C copticum. © 2016 Society of Chemical Industry...

  18. Ultra-short pulse delivery at high average power with low-loss hollow core fibers coupled to TRUMPF's TruMicro laser platforms for industrial applications

    Science.gov (United States)

    Baumbach, S.; Pricking, S.; Overbuschmann, J.; Nutsch, S.; Kleinbauer, J.; Gebs, R.; Tan, C.; Scelle, R.; Kahmann, M.; Budnicki, A.; Sutter, D. H.; Killi, A.

    2017-02-01

    Multi-megawatt ultrafast laser systems at micrometer wavelength are commonly used for material processing applications, including ablation, cutting and drilling of various materials or cleaving of display glass with excellent quality. There is a need for flexible and efficient beam guidance, avoiding free space propagation of light between the laser head and the processing unit. Solid core step index fibers are only feasible for delivering laser pulses with peak powers in the kW-regime due to the optical damage threshold in bulk silica. In contrast, hollow core fibers are capable of guiding ultra-short laser pulses with orders of magnitude higher peak powers. This is possible since a micro-structured cladding confines the light within the hollow core and therefore minimizes the spatial overlap between silica and the electro-magnetic field. We report on recent results of single-mode ultra-short pulse delivery over several meters in a lowloss hollow core fiber packaged with industrial connectors. TRUMPF's ultrafast TruMicro laser platforms equipped with advanced temperature control and precisely engineered opto-mechanical components provide excellent position and pointing stability. They are thus perfectly suited for passive coupling of ultra-short laser pulses into hollow core fibers. Neither active beam launching components nor beam trackers are necessary for a reliable beam delivery in a space and cost saving packaging. Long term tests with weeks of stable operation, excellent beam quality and an overall transmission efficiency of above 85 percent even at high average power confirm the reliability for industrial applications.

  19. Weighted finite impulse response filter for chromatic dispersion equalization in coherent optical fiber communication systems

    Science.gov (United States)

    Zeng, Ziyi; Yang, Aiying; Guo, Peng; Feng, Lihui

    2018-01-01

    Time-domain CD equalization using finite impulse response (FIR) filter is now a common approach for coherent optical fiber communication systems. The complex weights of FIR taps are calculated from a truncated impulse response of the CD transfer function, and the modulus of the complex weights is constant. In our work, we take the limited bandwidth of a single channel signal into account and propose weighted FIRs to improve the performance of CD equalization. The key in weighted FIR filters is the selection and optimization of weighted functions. In order to present the performance of different types of weighted FIR filters, a square-root raised cosine FIR (SRRC-FIR) and a Gaussian FIR (GS-FIR) are investigated. The optimization of square-root raised cosine FIR and Gaussian FIR are made in term of the bit rate error (BER) of QPSK and 16QAM coherent detection signal. The results demonstrate that the optimized parameters of the weighted filters are independent of the modulation format, symbol rate and the length of transmission fiber. With the optimized weighted FIRs, the BER of CD equalization signal is decreased significantly. Although this paper has investigated two types of weighted FIR filters, i.e. SRRC-FIR filter and GS-FIR filter, the principle of weighted FIR can also be extended to other symmetric functions super Gaussian function, hyperbolic secant function and etc.

  20. Removal of humic acid by a new type of electrical hollow-fiber microfiltration (E-HFMF)

    Science.gov (United States)

    Shang, Ran; Deng, Hui-ping; Hu, Jing-yi

    2010-11-01

    Low pressure membrane filtration, such as microfiltration, was widely used in the field of drinking water purification in the past few decades. Traditional microfiltration membranes are not efficient enough in the removal of natural organic matters (NOM) from raw water. Moreover, they tend to be fouled by the NOM and the filtration age of the membranes is thus shrinked. To tackle these problems, a new type of electrical hollow-fiber microfiltration module (E-HFMF) was designed. In the E-HFMF module, the hollow-fiber microfiltration membranes were placed into the radialized electrical field which functioned from the centre to the exterior of the cylindrical cavity. The main goal of the present study was to evaluate the efficiency of E-HFMF to remove the humic acid (HA, one of the main components of NOM). According to the parallel tests compared with the traditional microfiltration, the removal rate of humic acid was raised to 70%˜85% in terms of UV-254 and to 60%˜75% in terms of DOC when filtrating with the E-HFMF, while the removal rates of humic acid were 10%˜20% and 1%˜10% respectively when filtrating with the traditional microfiltration. The negative charged humic acid moved to the anode because of the electrophoresis, so few humic acid could be able to permeate through the membrane. The electrophoresis mobility of the humic acid permeating through the traditional microfiltration decreased by 19%, while the same index from the E-HFMF decreased by 75%. This indicated that the electrophoresis played a significant role on removing the humic acid. According to the gel permeate chromatograph analysis, humic acid aggregated in an electric field and thus forms loose and permeable cake layer on the membrane surface, which also relieved membrane fouling. Meanwhile, the negative charged humic acid migrating to the anode at the center minimized the deposition onto the membrane surface, and eliminated the membrane fouling as a result. During the E-HFMF filtration, the

  1. Application of hollow fiber liquid phase microextraction for simultaneous determination of regulated and emerging iodinated trihalomethanes in drinking water.

    Science.gov (United States)

    Domínguez-Tello, A; Arias-Borrego, A; García-Barrera, T; Gómez-Ariza, J L

    2015-07-10

    Trihalomethanes (THMs) are regulated disinfection by-products (DBPs) most commonly analyzed in quality control water supply due to their harmful effects on health. However, few data exist about the content of emerging iodo-trihalomethanes (I-THMs) which are present in drinking water at very low concentrations (in the order of ngL(-1)). For this reason a two-phase hollow fiber liquid phase microextraction method for the simultaneous determination of four regulated trihalomethanes and six emerging iodo-trihalomethanes using GC-μECD and GC-MS with detection limits in the range of few ngL(-1) has been developed. A central composite design was used to optimize conditions for simultaneous extraction. The best extraction recovery was obtained with 19.2min at 27.1°C and 900rpm, without salt addition, using a supported hollow fiber membrane of 10.5cm (0.6mm id) and 1-octanol as acceptor phase. The limits of detection for the regulated THMs and I-THMs were 3-44ngL(-1) and 1-3ngL(-1), respectively. The calibration curves showed good linearity (R(2)>0.995) and good repeatibility (3-22%). The relative recoveries in water were between 96.5% and 105.2%. The method was applied for the simultaneous determination of trihalomethanes in supply water samples from seven water distribution systems (WDS) in the Huelva area, located at the southwest Spain, which use different water-treatment processes. The highest concentrations of I-THMs, particularly CHBrClI and CHCl2I, were detected in water treated with advanced treatment process using pre-ozonation, however these compounds were not detected or decreased along distribution system. In the samples of treated water with conventional treatment, using pre-oxidation by permanganate and distribution network, CHCl2I, CHBrClI, CHClI2, CHBrI2 and CHI3 were detected at very low concentrations (1-18ngL(-1)). Finally, in water samples from underground origin without oxidation treatment, in which only disinfection with sodium hypochlorite was

  2. Mode conversion in a tapered fiber via a whispering gallery mode resonator and its application as add/drop filter.

    Science.gov (United States)

    Huang, Ligang; Wang, Jie; Peng, Weihua; Zhang, Wending; Bo, Fang; Yu, Xuanyi; Gao, Feng; Chang, Pengfa; Song, Xiaobo; Zhang, Guoquan; Xu, Jingjun

    2016-02-01

    Based on the conversion between the fundamental mode (LP01) and the higher-order mode (LP11) in a tapered fiber via a whispering gallery mode resonator, an add/drop filter was proposed and demonstrated experimentally, in which the resonator only interacted with one tapered fiber, rather than two tapered fibers as in conventional configurations. The filter gains advantages of easy alignment and low scattering loss over the other filters based on tapered fiber and resonator, and will be useful in application.

  3. Membrane solid phase microextraction with alumina hollow fiber on line coupled with ICP-OES for the determination of trace copper, manganese and nickel in environmental water samples

    Energy Technology Data Exchange (ETDEWEB)

    Cui Chao; He Man [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin, E-mail: binhu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2011-03-15

    A novel alumina hollow fiber was synthesized by sol-gel template method and was characterized by scanning electron microscopy, N{sub 2} adsorption technique and X-ray diffraction. With the use of prepared alumina hollow fiber as extraction membrane, a new method of flow injection (FI)-membrane solid phase microextraction (MSPME) on-line coupled to inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for simultaneous determination of trace metals (Cu, Mn and Ni) in environmental water samples. The adsorption capacities of the alumina hollow fiber for Cu, Mn and Ni were found to be 6.6, 8.7 and 13.3 mg g{sup -1}, respectively. With a preconcentration factor of 10, the limits of detection (LODs) for Cu, Mn and Ni were found to be 0.88, 0.61 and 0.38 ng mL{sup -1}, respectively, and the relative standard deviations (RSDs) were ranging from 6.2 to 7.9% (n = 7, c = 10 ng mL{sup -1}). To validate the accuracy, the proposed method was applied to the analysis of certified reference material GSBZ50009-88 environmental water and the determined values are in good agreement with the certified values. The developed method was also employed for the analysis of Yangtze River water and East Lake water, and the recoveries for the spiked samples were in the range of 87.4-110.2%.

  4. Robust outer-selective thin-film composite polyethersulfone hollow fiber membranes with low reverse salt flux for renewable salinity-gradient energy generation

    KAUST Repository

    Cheng, Zhen Lei

    2016-01-08

    This study reports outer-selective thin-film composite (TFC) hollow fiber membranes with extremely low reverse salt fluxes and robustness for harvesting salinity-gradient energy from pressure retarded osmosis (PRO) processes. Almost defect-free polyamide layers with impressive low salt permeabilities were synthesized on top of robust polyethersulfone porous supports. The newly developed TFC-II membrane shows a maximum power density of 7.81 W m−2 using 1 M NaCl and DI water as feeds at 20 bar. Reproducible data obtained in the 2nd and 3rd runs confirm its stability under high hydraulic pressure differences. Comparing to other PRO membranes reported in the literature, the newly developed membrane exhibits not only the smallest slope between water flux decline and ΔPΔP increase but also the lowest ratio of reverse salt flux to water flux. Thus, the effective osmotic driving force could be well maintained even under high pressure operations. For the first time, the effect of feed pressure buildup induced by feed flowrate was evaluated towards PRO performance. A slight increment in feed pressure buildup was found to be beneficial to water flux and power density up to 10.06 W m−2 without comprising the reverse salt flux. We believe this study may open up new perspectives on outer-selective PRO hollow fiber membranes and provide useful insights to understand and design next-generation outer-selective TFC hollow fiber membranes for osmotic power generation.

  5. Preparation of robust braid-reinforced poly(vinyl chloride) ultrafiltration hollow fiber membrane with antifouling surface and application to filtration of activated sludge solution.

    Science.gov (United States)

    Zhou, Zhuang; Rajabzadeh, Saeid; Fang, Lifeng; Miyoshi, Taro; Kakihana, Yuriko; Matsuyama, Hideto

    2017-08-01

    Braid-reinforced hollow fiber membranes with high mechanical properties and considerable antifouling surface were prepared by blending poly(vinyl chloride) (PVC) with poly(vinyl chloride-co-poly(ethylene glycol) methyl ether methacrylate) (poly(VC-co-PEGMA)) copolymer via non-solvent induced phase separation (NIPS). The tensile strength of the braid-reinforced PVC hollow fiber membranes were significantly larger than those of previously reported various types of PVC hollow fiber membranes. The high interfacial bonding strength indicated the good compatibility between the coating materials and the surface of polyethylene terephthalate (PET)-braid. Owing to the surface segregation phenomena, the membrane surface PEGMA coverage increased upon increasing the poly(VC-co-PEGMA)/PVC blending ratio, resulting in higher hydrophilicities and bovine serum albumin (BSA) repulsion. To compare the fouling properties, membranes with similar PWPs were prepared by adjusting the dope solution composition to eliminate the effect of hydrodynamic conditions on the membrane fouling performance. The blend membranes surface exhibited considerable fouling resistance to the molecular adsorption from both BSA solution and activated sludge solution. In both cases, the flux recovered to almost 80% of the initial flux using only water backflush. Considering their great mechanical properties and antifouling resistance to activated sludge solution, these novel membranes show good potential for application in wastewater treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Derivatization following hollow-fiber microextraction with tetramethylammonium acetate as a dual-function reagent for the determination of benzoic acid and sorbic acid by GC.

    Science.gov (United States)

    Sun, Yang; Wang, Xiaoqing; Huang, Yilei; Pan, Zaifa; Wang, Lili

    2013-07-01

    Derivatization at the injection port following hollow-fiber-based liquid-liquid-liquid microextraction with tetramethylammonium acetate as a dual-function reagent, i.e. an acceptor and derivatization reagent, for the determination of benzoic acid (BA) and sorbic acid (SA) in real samples by GC was developed. BA and SA were extracted from aqueous samples to an organic phase impregnated into the pores of the hollow fiber wall, and then back-extracted to the acceptor solution located inside the lumen of the hollow fiber. Upon injection, the extracted analytes were quantitatively derivatized to their methyl esters with tetramethylammonium acetate in the GC injection port. Several parameters related to the derivatization and extraction efficiency were optimized. The linearity was satisfactory over a concentration range of 0.1-50 mg/L with r > 0.993 for both analytes. The LODs were 2.0 μg/L for SA and 20 μg/L for BA. The recoveries (83-116%) and precisions (RSDs of 1.2-11.4% (n = 3)) were examined by analyzing real spiked samples. The enrichment factors of BA and SA were 300 and 425. The results demonstrated that this is a simple, rapid, accurate, and sensitive method for the determination of BA and SA in various samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A low-cost mullite-titania composite ceramic hollow fiber microfiltration membrane for highly efficient separation of oil-in-water emulsion.

    Science.gov (United States)

    Zhu, Li; Chen, Mingliang; Dong, Yingchao; Tang, Chuyang Y; Huang, Aisheng; Li, Lingling

    2016-03-01

    Oil-in-water (O/W) emulsion is considered to be difficult to treat. In this work, a low-cost multi-layer-structured mullite-titania composite ceramic hollow fiber microfiltration membrane was fabricated and utilized to efficiently remove fine oil droplets from (O/W) emulsion. In order to reduce membrane cost, coal fly ash was effectively recycled for the first time to fabricate mullite hollow fiber with finger-like and sponge-like structures, on which a much more hydrophilic TiO2 layer was further deposited. The morphology, crystalline phase, mechanical and surface properties were characterized in details. The filtration capability of the final composite membrane was assessed by the separation of a 200 mg·L(-1) synthetic (O/W) emulsion. Even with this microfiltration membrane, a TOC removal efficiency of 97% was achieved. Dilute NaOH solution backwashing was used to effectively accomplish membrane regeneration (∼96% flux recovery efficiency). This study is expected to guide an effective way to recycle waste coal fly ash not only to solve its environmental problems but also to produce a high-valued mullite hollow fiber membrane for highly efficient separation application of O/W emulsion with potential simultaneous functions of pure water production and oil resource recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Evidence for and implications of self-background of radon dosimeters with glass-fiber filters

    NARCIS (Netherlands)

    Put, L.W.; Lembrechts, J.; van der Graaf, E.R.; Stoop, P.

    The first national radon survey in the Netherlands was conducted in 1984 with passive radon dosimeters that contain glass-fiber diffusion filters. During the last few years, measurements of outdoor-radon concentrations and information in the literature suggested to us that these dosimeters may give

  9. Low-loss tunable all-in-fiber filter for Raman spectroscopy

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Scolari, Lara; Lund-Hansen, Toke

    2011-01-01

    We show a novel in-line Rayleigh-rejection filter for Raman spectroscopy, based on a solid-core Photonic Crystal Fiber (PCF) filled with a high-index material. The device is low-loss and thermally tunable, and allows for a strong attenuation of the Rayleigh line at 532nm and the transmission...

  10. Design and analysis of a photonic crystal fiber based polarization filter using surface plasmon resonance

    Science.gov (United States)

    Yogalakshmi, S.; Selvendran, S.; Sivanantha Raja, A.

    2016-05-01

    A photonic crystal fiber with an active metal nanowire is proposed to act as a polarization filter based on the principle of plasmonic resonance. The light launched into the silica core gets coupled to gold wire inducing surface plasmon resonance, filtering one of the two orthogonally polarized light waves in the third optical communication window. This polarization filtering characteristic is analyzed using the finite element method. The change in the performance behaviour of the proposed filter is investigated by increasing the number of embedded gold wires, altering their positions and varying the diameter of gold wire. It is found that enhanced absorption of the core guided mode is achieved by replacing the filled metal nanowire with a metal coating around the air hole. Filtering of any or both polarizations can be attained by suitably positioning the metal wires. Confinement loss as high as 348.55 and 302 dB cm-1 for y-polarized and x-polarized lights respectively are attained at 1.52 and 1.56 μm respectively for single gold wire. The filter acts as a single polarization filter filtering x-polarized light with a confinement loss value of 187.67 dB cm-1 when two gold nanowires are placed adjacently. The same structure acts as the filter for y-polarized light by employing gold coating exhibiting an increased confinement loss of 406.34 dB cm-1 at 1.64 μm.

  11. Switching of light with light using cold atoms inside a hollow optical fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Peyronel, Thibault

    2010-01-01

    We demonstrate a fiber-optical switch that operates with a few hundred photons per switching pulse. The light-light interaction is mediated by laser-cooled atoms. The required strong interaction between atoms and light is achieved by simultaneously confining photons and atoms inside the microscop...

  12. Hollow fiber dead-end ultrafiltration: Influence of ionic environment on filtration of alginates

    NARCIS (Netherlands)

    van de Ven, W.J.C.; van 't Sant, K.; Punt, Ineke G.M.; Zwijnenburg, A.; Kemperman, Antonius J.B.; van der Meer, Walterus Gijsbertus Joseph; Wessling, Matthias

    2008-01-01

    We analyze the filterability of sodium alginate solutions in different ionic environments as a function of the operational flux. The alginates serve as a model component for polysaccharides in feed water. Next to filtration characteristics, the fouling reversibility was studied by employing strictly

  13. Periodic and non-periodic frequency selection in an erbium doped fiber laser by silica microdisk optical cavity filters.

    Science.gov (United States)

    Bergeron, Sacha; Saïdi, Samir; Peter, Yves-Alain

    2010-08-02

    Integrated silica microdisk resonators can be used to create a variety of very high performance spectral filters. These filters can control the spectral emission of an erbium doped fiber laser. By modifying the number and sizes of the microdisks constituting these filters it is possible to produce single wavelength, periodic multi-frequency and non-periodic multi-wavelength fiber lasers. Channel spacing as low as 0.28 nm and non-periodic four wavelength lasers were demonstrated.

  14. Tunable passively harmonic mode-locked Yb-doped fiber laser with Lyot-Sagnac filter.

    Science.gov (United States)

    Li, Ming; Zou, Xin; Wu, Jian; Shi, Jindan; Qiu, Jifang; Hong, Xiaobin

    2015-10-10

    A novel passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all normal dispersion is proposed and experimentally demonstrated based on a semiconductor saturable absorption mirror and tunable Lyot-Sagnac filter. By only tuning the bandwidth of the filter at fixed pump power, the repetition rate of 9.87 to 167.8 MHz (corresponding to 17th-order harmonic) is obtained. This is the highest repetition rate and harmonic order for a passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all-normal dispersion to the best of our knowledge. The signal-to-noise ratio and super-mode suppression ratio for all harmonic orders are higher than 65 and 35 dB, respectively, which shows the high stability of the fiber laser.

  15. A simple gold-coated microstructure fiber polarization filter in two communication windows

    Science.gov (United States)

    Feng, Xinxing; Li, Shuguang; Du, Huijing; Zhang, Yinan; Liu, Qiang

    2018-03-01

    A polarization filter is designed at two communication windows of 1310 and 1550 nm based on microstructured optical fiber. The model has four large diameter air holes and two gold-coated air holes. The influence of the geometrical parameters of the photonic crystal fiber on the performance of the polarization filter is analyzed by the finite element method. The numerical simulation shows that when the fiber length is 300 μm, the corresponding extinction ratio is 209.7 dB and 179.8 dB, the bandwidth of extinction ratio (ER) better than 20 dB is 150 nm and 350 nm at the communication wavelength of 1310 nm and 1550 nm.

  16. Tunable and reconfigurable multi-tap microwave photonic filter based on dynamic Brillouin gratings in fibers.

    Science.gov (United States)

    Sancho, J; Primerov, N; Chin, S; Antman, Y; Zadok, A; Sales, S; Thévenaz, L

    2012-03-12

    We propose and experimentally demonstrate new architectures to realize multi-tap microwave photonic filters, based on the generation of a single or multiple dynamic Brillouin gratings in polarization maintaining fibers. The spectral range and selectivity of the proposed periodic filters is extensively tunable, simply by reconfiguring the positions and the number of dynamic gratings along the fiber respectively. In this paper, we present a complete analysis of three different configurations comprising a microwave photonic filter implementation: a simple notch-type Mach-Zehnder approach with a single movable dynamic grating, a multi-tap performance based on multiple dynamic gratings and finally a stationary grating configuration based on the phase modulation of two counter-propagating optical waves by a common pseudo-random bit sequence (PRBS).

  17. An optical fiber MEMS pressure sensor using microwave photonics filtering technique

    Science.gov (United States)

    Wang, Yiping; Wang, Ming; Ni, Xiaoqi; Xia, Wei; Guo, Dongmei; Hao, Hui; Ma, Qingyu; Zhuang, Wei

    2017-04-01

    A fiber-optic micro-electromechanical systems (MEMS) extrinsic Fabry-Perot interferometer (EFPI) pressure sensor exploiting microwave photonics filtering technique is firstly proposed and experimentally demonstrated. A single-bandpass microwave photonic filter (MPF) which mainly consists of a spectrum-sliced light source, a pressurized EFPI, a phase modulator (PM) and a length of dispersion compensating fiber (DCF) is demonstrated. The frequency response of the filter with respect to the pressure is studied. By detecting the resonance frequency shifts of the MPF, the pressure can be determined. The theoretical and experimental results show that the proposed EFPI pressure sensor has a higher resolution and higher speed than traditional methods based on optical spectrum analysis. The sensitivity of the sensor is measured to be as high as 86 MHz/MPa in the range of 0-4MPa.

  18. Design and realization of an all-fiber broadband tunable gain equalization filter for DWDM signals.

    Science.gov (United States)

    Varshney, R K; Nagaraju, B; Singh, A; Pal, B P; Kar, A K

    2007-10-17

    Design and fabrication of a tunable gain equalization filter for dense wavelength division multiplexed (DWDM) signals through erbium doped fiber amplifiers (EDFA) is reported. It is based on a side-polished fiber (SPF) half-coupler block loaded with a displaceable tapered multimode overlay waveguide (MMOW). A simple and accurate normal mode analysis is employed to design this filtering device for its subsequent realization. Equalization of a typical EDFA gain spectrum in the C-band within +/-0.35 dB or even less in the presence of various ITU standard C-band DWDM signal channels is demonstrated under varied operating conditions like add/drop of signals. Tunability of the filter notch is achieved through displacement of the SPF relative to the MMOW.

  19. Osmotic distillation and quality evaluation of sucrose, apple and orange juices in hollow fiber membrane contactor

    Directory of Open Access Journals (Sweden)

    Rehman Waheed Ur

    2017-01-01

    Full Text Available Sucrose solution, apple and orange juices were concentrated through osmotic distillation (OD process using a mini-module Liqui-CelTM hollow fibre membrane contactor. Mass transport characteristics of water molecules from feed to stripping solution were studied. Process parameters such as feed temperature, feed flow rate and concentration of stripping solution (CaCl2 were varied. Sucrose solution was concentrated from 135 to 510 g TSS kg-1 in 340 min using feed-in- -lumen flow configuration at a start-up water flux of 0.250 L m-2 h-1 and a temperature of 30°C. Similarly, it was concentrated up to 510 g TSS kg-1 in 200 min using feed-in-shell flow configuration at a start-up water flux of 0.505 L m-2 hr1 and a temperature of 30°C. In a total recycle time of 340 min, clarified apple and orange juices were concentrated up to 500 g TSS kg-1 using feed-in-lumen flow configuration at a start-up water flux of 0.204 and 0.294 L m-2 hr1, respectively. It was found that quality parameters of fruit juices were well improved after the osmotic distillation process. The process therefore has good potential for application in the fruit processing industry for concentration of fruit juices.

  20. Generation of surface-wave microwave microplasmas in hollow-core photonic crystal fiber based on a split-ring resonator.

    Science.gov (United States)

    Vial, Florian; Gadonna, Katell; Debord, Benoît; Delahaye, Frédéric; Amrani, Foued; Leroy, Olivier; Gérôme, Frédéric; Benabid, Fetah

    2016-05-15

    We report on a new and highly compact scheme for the generation and sustainment of microwave-driven plasmas inside the core of an inhibited coupling Kagome hollow-core photonic crystal fiber. The microwave plasma generator consists of a split-ring resonator that efficiently couples the microwave field into the gas-filled fiber. This coupling induces the concomitant generation of a microwave surface wave at the fiber core surround and a stable plasma column confined in the fiber core. The scheme allowed the generation of several centimeters long argon microplasma columns with a very low excitation power threshold. This result represents an important step toward highly compact plasma lasers or plasma-based photonic components.

  1. Removal of antibiotics in sponge membrane bioreactors treating hospital wastewater: Comparison between hollow fiber and flat sheet membrane systems.

    Science.gov (United States)

    Nguyen, Thanh-Tin; Bui, Xuan-Thanh; Luu, Vinh-Phuc; Nguyen, Phuoc-Dan; Guo, Wenshan; Ngo, Huu-Hao

    2017-09-01

    Hollow fiber (HF) and flat sheet (FS) Sponge MBRs were operated at 10-20 LMH flux treating hospital wastewater. Simultaneous nitrification denitrification (SND) occurred considerably with TN removal rate of 0.011-0.020mg TN mgVSS(-1)d(-1). Furthermore, there was a remarkable removal of antibiotics in both Sponge MBRs, namely Norfloxacin (93-99% (FS); 62-86% (HF)), Ofloxacin (73-93% (FS); 68-93% (HF)), Ciprofloxacin (76-93% (FS); 54-70% (HF)), Tetracycline (approximately 100% for both FS and HF) and Trimethoprim (60-97% (FS); 47-93% (HF). Whereas there was a quite high removal efficiency of Erythromycin in Sponge MBRs, with 67-78% (FS) and 22-48% (HF). Moreover, a slightly higher removal of antibiotics in FS than in HF achieved, with the removal rate being of 0.67-32.40 and 0.44-30.42µgmgVSS(-1)d(-1), respectively. In addition, a significant reduction of membrane fouling of 2-50 times was achieved in HF-Sponge MBR for the flux range. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Application of hollow fiber vitrification for cryopreservation of bovine early cleavage stage embryos and porcine morula-blastomeres.

    Science.gov (United States)

    Uchikura, Ayuko; Matsunari, Hitomi; Nakano, Kazuaki; Hatae, Shota; Nagashima, Hiroshi

    2016-04-22

    A novel hollow fiber vitrification (HFV) method was applied to materials that have previously been difficult to cryopreserve, thereby expanding the potential application of this method. The results showed that zona-free porcine morulae and their isolated blastomeres remained viable even after vitrification. The rate of development to blastocysts after vitrification was similar for zona-free and zona-intact morulae (21/23, 91.3% for both). Vitrified blastomeres had a developmental potential equal to that of non-vitrified blastomeres (blastocyst formation rate after reaggregation: 16/17, 94.1% for both). The HFV method was also effective for the cryopreservation of in vitro matured/fertilized bovine embryos at the 2- to 4-cell, 8- to 16-cell and morula stages. The blastocyst formation rates of vitrified embryos (66.1-82.5%) were similar to those of non-vitrified embryos (74.5-82.5%). These results indicate that this novel HFV method is an effective tool for embryo cryopreservation that can enhance current practices in reproductive biology.

  3. In-situ grafting to improve polarity of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes for CO2 separation.

    Science.gov (United States)

    Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2018-01-15

    Surface grafting modification was proposed to improve the surface polarity of polyacrylonitrile hollow fiber-supported polydimethylsiloxane (PDMS) membrane. The initiator 3-aminopropyltriethoxysilane containing one amine group was integrated into PDMS, and polyvinyl pyrrolidone (PVP) with strong polarity was connected to the surface by reacting with amine groups. Surface grafting modification was proven on X-ray photoelectron spectroscopy. The sharp decrease (from ∼98° to ∼28°) in water contact angle of the PDMS membrane indicated the significant improvement in surface polarity after the modification. The surface roughness of the PDMS membrane increased with the modification, and the PDMS surface immersed for 40s was almost covered with PVP. The membrane immersed in PVP solution for 10s improved CO2/H2, CO2/CH4, and CO2/N2 selectivities. While CO2 permeance slightly decreased from ∼2500 GPU to ∼2440 GPU. For the separation of CO2/CH4 and CO2/N2 mixed gases, all CO2/CH4 and CO2/N2 selectivities were improved after the modification. For the separation of CO2/H2 mixed gas, CO2/H2 selectivity was improved when the immersion time was below 30 s. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. CFD simulation of copper(II) extraction with TFA in non-dispersive hollow fiber membrane contactors.

    Science.gov (United States)

    Muhammad, Amir; Younas, Mohammad; Rezakazemi, Mashallah

    2018-01-27

    This study presents computational fluid dynamics (CFD) simulation of dispersion-free liquid-liquid extraction of copper(II) with trifluoroacetylacetone (TFA) in hollow fiber membrane contactor (HFMC). Mass and momentum balance Navier-Stokes equations were coupled to address the transport of copper(II) solute across membrane contactor. Model equations were simulated using COMSOL Multiphysics™. The simulation was run to study the detailed concentration distribution of copper(II) and to investigate the effects of various parameters like membrane characteristics, partition coefficient, and flow configuration on extraction efficiency. Once-through extraction was found to be increased from 10 to 100% when partition coefficient was raised from 1 to 10. Similarly, the extraction efficiency was almost doubled when porosity to tortuosity ratio of membrane was increased from 0.05 to 0.81. Furthermore, the study revealed that CFD can be used as an effective optimization tool for the development of economical membrane-based dispersion-free extraction processes.

  5. Investigation of H2S and CO2 Removal from Gas Streams Using Hollow Fiber Membrane Gas–liquid Contactors

    Directory of Open Access Journals (Sweden)

    S. M. Mirfendereski

    2017-07-01

    Full Text Available Chemical absorption of H2S and CO2 from CH4 was carried out in a polypropylene porous asymmetric hollow fiber membrane contactor (HFMC. A 0.5 mol L–1 aqueous solution of methyldiethanolamine (MDEA was used as chemical absorbent solution. Effects of gas flow rate, liquid flow rate, H2S concentration and CO2 concentration on the H2S outlet concentrations and CO2 removal percentage were investigated. The results showed that the removal of H2S with aqueous solution of MDEA was very high and indicated almost total removal of H2S. Experimental results also indicated that the membrane contactor was very efficient in the removal of trace H2S at high gas/ liquid flow ratio. The removal of H2S was almost complete with a recovery of more than 96 %. Using feed gas mixtures containing 5000 ppm H2S with CO2 concentrations in the range of 4–12 vol.%, the outlet H2S concentration of less than 1.0 ppm was attained with less than 4.0 vol.% of CO2 permeated and absorbed.

  6. A comparison of mass transfer coefficients between trickle-bed, hollow fiber membrane and stirred tank reactors.

    Science.gov (United States)

    Orgill, James J; Atiyeh, Hasan K; Devarapalli, Mamatha; Phillips, John R; Lewis, Randy S; Huhnke, Raymond L

    2013-04-01

    Trickle-bed reactor (TBR), hollow fiber membrane reactor (HFR) and stirred tank reactor (STR) can be used in fermentation of sparingly soluble gasses such as CO and H2 to produce biofuels and bio-based chemicals. Gas fermenting reactors must provide high mass transfer capabilities that match the kinetic requirements of the microorganisms used. The present study compared the volumetric mass transfer coefficient (K(tot)A/V(L)) of three reactor types; the TBR with 3 mm and 6 mm beads, five different modules of HFRs, and the STR. The analysis was performed using O2 as the gaseous mass transfer agent. The non-porous polydimethylsiloxane (PDMS) HFR provided the highest K(tot)A/V(L) (1062 h(-1)), followed by the TBR with 6mm beads (421 h(-1)), and then the STR (114 h(-1)). The mass transfer characteristics in each reactor were affected by agitation speed, and gas and liquid flow rates. Furthermore, issues regarding the comparison of mass transfer coefficients are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Fouling behaviors of polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes for engineering osmosis processes

    KAUST Repository

    Chen, Sicong

    2014-02-01

    This paper investigated the individual effects of reverse salt flux and permeate flux on fouling behaviors of as-spun and annealed polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes under forward osmosis (FO) and pressure retarded osmosis (PRO) processes. Two types of membrane fouling had been studied; namely, inorganic fouling (CaSO4·2H2O gypsum scaling) during FO operations and organic fouling (sodium alginate fouling) during PRO operations. It is found that gypsum scaling on the membrane surface may be inhibited and even eliminated with an increase in reverse MgCl2 flux due to competitive formations of MgSO4° and CaSO4·2H2O. In contrast, the increase of reverse NaCl flux exhibits a slight enhancement on alginate fouling in both FO and PRO processes. Comparing to the reverse salt flux, the permeate flux always plays a dominant role in fouling. Therefore, lesser fouling has been observed on the membrane surface under the pressurized PRO process than FO process because the reduced initial flux mitigates the fouling phenomena more significantly than the enhancement caused by an increase in reverse NaCl flux. © 2013 Elsevier B.V.

  8. Sensitivity of Hollow Fiber Spacesuit Water Membrane Evaporator Systems to Potable Water Constituents, Contaminants and Air Bubbles

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis A.; Fritts, Sharon; Tsioulos, Gus

    2008-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning and compares the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source. Some of the impurities in potable water are volatile, such as the organics, while others, such as the metals and inorganic ions are nonvolatile. The non-volatile constituents will concentrate in the SWME as evaporated water from the loop is replaced by the feedwater. At some point in the SWME mission lifecycle as the concentrations of the non-volatiles increase, the solubility limits of one or more of the constituents may be reached. The resulting presence of precipitate in the coolant water may begin to plug pores and tube channels and affect the SWME performance. Sensitivity to macroparticles, lunar dust simulant, and air bubbles will also be investigated.

  9. Feasibility Study of Advanced NOM-Reduction by Hollow Fiber Ultrafiltration and Nanofiltration at a Swedish Surface Water Treatment Plant

    Directory of Open Access Journals (Sweden)

    Angelica Lidén

    2016-04-01

    Full Text Available Membrane technology, i.e., ultrafiltration and nanofiltration, is growing in popularity, as it is a space efficient alternative for surface water treatment. Two types of hollow fiber membranes were tested in a fully equipped and automated pilot at a Swedish water treatment plant. Raw water was treated by a nanofilter and by coagulation before an ultrafilter. Operation parameters recorded during these trials have been the basis for cost estimations and assessments of environmental impact, comparing the two membrane modules to the existing conventional treatment. The membranes required lower chemical consumption, but led to increased costs from membrane modules and a higher energy demand. Compared to the existing treatment (0.33 €/m3, the operational costs were estimated to increase 6% for ultrafiltration and 30% for nanofiltration. Considering the low emissions from Nordic energy production, the membrane processes would lower the environmental impact, including factors such as climate and ecosystem health. Greenhouse gas emissions would decrease from 161 g CO2-eq/m3 of the existing process, to 127 g CO2-eq/m3 or 83 g CO2-eq/m3 for ultrafiltration and nanofiltration, respectively. Lower chemical consumption and less pollution from the sludge leaving the water treatment plant lead to lower impacts on the environment.

  10. Gypsum (CaSO42H2O) scaling on polybenzimidazole and cellulose acetate hollow fiber membranes under forward osmosis

    KAUST Repository

    Chen, Si Cong

    2013-11-08

    We have examined the gypsum (CaSO42H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42 14.85 after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. 2013 by the authors; licensee MDPI, Basel, Switzerland.

  11. Hemoglobin Regulates the Metabolic, Synthetic, Detoxification, and Biotransformation Functions of Hepatoma Cells Cultured in a Hollow Fiber Bioreactor

    Science.gov (United States)

    Chen, Guo

    2010-01-01

    Hepatic hollow fiber (HF) bioreactors constitute one type of extracorporeal bioartificial liver assist device (BLAD). Ideally, cultured hepatocytes in a BLAD should closely mimic the in vivo oxygenation environment of the liver sinusoid to yield a device with optimal performance. However, most BLADs, including hepatic HF bioreactors, suffer from O2 limited transport toward cultured hepatocytes, which reduces their performance. We hypothesize that supplementation of hemoglobin-based O2 carriers into the circulating cell culture medium of hepatic HF bioreactors is a feasible and effective strategy to improve bioreactor oxygenation and performance. We examined the effect of bovine hemoglobin (BvHb) supplementation (15 g/L) in the circulating cell culture medium of hepatic HF bioreactors on hepatocyte proliferation, metabolism, and varied liver functions, including biosynthesis, detoxification, and biotransformation. It was observed that BvHb supplementation supported the maintenance of a higher cell mass in the extracapillary space, improved hepatocyte metabolic efficiency (i.e., hepatocytes consumed much less glucose), improved hepatocyte capacity for drug metabolism, and conserved both albumin synthesis and ammonia detoxification functions compared to controls (no BvHb supplementation) under the same experimental conditions. PMID:20528678

  12. FOST 2 Upgrade with Hollow-Fiber CTA FO Module and Generation of Osmotic Agent for Microorganism Growth Studies

    Science.gov (United States)

    Parodi, Jurek; Mangado, Jaione Romero; Stefanson, Ofir; Flynn, Michael; Shaw, Hali; Beeler, David

    2016-01-01

    FOST 2 is an integrated membrane system that incorporates a forward osmosis subsystem and a reverse osmosis subsystem working in series. It has been designed as a post treatment system to process the effluent from the Membrane Aerated Biological Reactor developed at NASA Johnson Space Center and Texas Tech University. Its function is to remove dissolved solids residual such as ammonia and suspended solids, as well as to provide a physical barrier to microbial and viral contamination. A tubular CTA membrane module from HTI and a flat-sheet lipid-base membrane module from Porifera were integrated and tested on FOST 2 in the past, using both a bioreactor's effluent and greywater as the feed solution. This paper documents the performance of FOST 2 after its upgrade with a hollow-fiber CTA membrane module from Toyobo, treating real black-water to generate the osmotic agent solution necessary to conduct growth studies of genetically engineered microorganism for the Synthetic Biological Membrane project.

  13. Recycling of phenol from aqueous solutions by pervaporation with ZSM-5/PDMS/PVDF hollow fiber composite membrane

    Science.gov (United States)

    Li, Dan; Yao, Jie; Sun, Hao; Liu, Bing; van Agtmaal, Sjack; Feng, Chunhui

    2018-01-01

    Zeolite (ZSM-5)/polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) hollow fiber composite membrane was prepared by dynamic negative pressure. The influence of ZSM-5 silanization, coating time and concentration of ZSM-5 on the resulting pervaporation (PV) performance of composite membranes was investigated. The contact angle (CA) was used to measure surface hydrophobic property and it was found that the water contact angle of the membrane was increased significantly from 99° to 132° when the concentration of ZSM-5 increased from 0% to 50%. The morphology of the membrane was characterized by scanning electron microscope (SEM) and those SEM images illustrated that the thickness of the separating layer has obvious differences at varying coating times. Furthermore, the membranes were investigated in PV process to recycle phenol from aqueous solutions as feed mixtures. The impact of phenol concentration in feed, temperature and pressure of penetration side on the PV performance of membrane was studied systematically. When the ZSM-5 concentration was 40% and the coating time was 60 min, separation factor and phenol permeability were 4.56 and 5.78 g/(m2 h), respectively. ZSM-5/PDMS/PVDF membrane significantly improved the recovery efficiency of phenols.

  14. Highly sensitive SERS detection of cancer proteins in low sample volume using hollow core photonic crystal fiber.

    Science.gov (United States)

    U S, Dinish; Fu, Chit Yaw; Soh, Kiat Seng; Ramaswamy, Bhuvaneswari; Kumar, Anil; Olivo, Malini

    2012-03-15

    Enzyme-linked immunosorbent assays (ELISA) are commonly used for detecting cancer proteins at concentration in the range of about ng-μg/mL. Hence it often fails to detect tumor markers at the early stages of cancer and other diseases where the amount of protein is extremely low. Herein, we report a novel photonic crystal fiber (PCF) based surface enhanced Raman scattering (SERS) sensing platform for the ultrasensitive detection of cancer proteins in an extremely low sample volume. As a proof of concept, epidermal growth factor receptors (EGFRs) in a lysate solution from human epithelial carcinoma cells were immobilized into the hollow core PCF. Highly sensitive detection of protein was achieved using anti-EGFR antibody conjugated SERS nanotag. This SERS nanotag probe was realized by anchoring highly active Raman molecules onto the gold nanoparticles followed by bioconjugation. The proposed sensing method can detect low amount of proteins at ∼100 pg in a sample volume of ∼10 nL. Our approach may lead to the highly sensitive protein sensing methodology for the early detection of diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Antiplasticization and plasticization of Matrimid® asymmetric hollow fiber membranes. Part B. Modeling

    KAUST Repository

    Lee, Jong Suk

    2010-03-15

    A previous paper characterized effects of exposure of Matrimid® asymmetric fibers to either toluene or n-heptane or a combination of both contaminants during permeation. In all cases, reductions in the carbon dioxide permeance and the carbon dioxide/methane selectivity were observed for both annealed and non-annealed samples. In this paper, the respective potential impacts of competitive sorption, fiber compaction, and antiplasticization/plasticization on membrane performance during contaminant exposure are quantified and analyzed. The combined impact of competitive sorption and antiplasticization/plasticization are shown to account for the loss in membrane performance observed during exposure to highly sorbing feed stream contaminants. The dual mode transport model for penetrant mixtures was used to explain reduction in CO2 permeance due to competitive sorption effects, while free volume-based modeling explained decrease in CO2 permeance due to antiplasticization. Finally, the impact on CO2 permeance during exposure of the annealed Matrimid® fibers to contaminants is analyzed. The analysis is based on reduction in segmental mobility expected due to reduction of residual unrelaxed volume as compared to unanealed sample. © 2010.

  16. Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles.

    Science.gov (United States)

    Sim, Kyoung Mi; Kim, Kyung Hwan; Hwang, Gi Byoung; Seo, SungChul; Bae, Gwi-Nam; Jung, Jae Hee

    2014-09-15

    Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Concurrent measurements of size-segregated particulate sulfate, nitrate and ammonium using quartz fiber filters, glass fiber filters and cellulose membranes

    Science.gov (United States)

    Tian, Shili; Pan, Yuepeng; Wang, Jian; Wang, Yuesi

    2016-11-01

    Current science and policy requirements have focused attention on the need to expand and improve particulate matter (PM) sampling methods. To explore how sampling filter type affects artifacts in PM composition measurements, size-resolved particulate SO42-, NO3- and NH4+ (SNA) were measured on quartz fiber filters (QFF), glass fiber filters (GFF) and cellulose membranes (CM) concurrently in an urban area of Beijing on both clean and hazy days. The results showed that SNA concentrations in most of the size fractions exhibited the following patterns on different filters: CM > QFF > GFF for NH4+; GFF > QFF > CM for SO42-; and GFF > CM > QFF for NO3-. The different patterns in coarse particles were mainly affected by filter acidity, and that in fine particles were mainly affected by hygroscopicity of the filters (especially in size fraction of 0.65-2.1 μm). Filter acidity and hygroscopicity also shifted the peaks of the annual mean size distributions of SNA on QFF from 0.43-0.65 μm on clean days to 0.65-1.1 μm on hazy days. However, this size shift was not as distinct for samples measured with CM and GFF. In addition, relative humidity (RH) and pollution levels are important factors that can enhance particulate size mode shifts of SNA on clean and hazy days. Consequently, the annual mean size distributions of SNA had maxima at 0.65-1.1 μm for QFF samples and 0.43-0.65 μm for GFF and CM samples. Compared with NH4+ and SO42-, NO3- is more sensitive to RH and pollution levels, accordingly, the annual mean size distribution of NO3- exhibited peak at 0.65-1.1 μm for CM samples instead of 0.43-0.65 μm. These methodological uncertainties should be considered when quantifying the concentrations and size distributions of SNA under different RH and haze conditions.

  18. Thermal effects in Yb-doped double-cladding Distributed Modal Filtering rod-type fibers

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Jørgensen, Mette Marie

    2012-01-01

    element method. A DMF fiber design, which is single-mode in the 1030 nm–1064 nm region, is considered, and the effects of thermal load on the transmission characteristics are evaluated. Results show a blue-shift of the single-mode window and the single-mode bandwidth narrowing as the absorbed pump power......The effects of thermally-induced refractive index change in Yb-doped Distributed Modal Filtering (DMF) photonic crystal fibers are investigated, where high-order mode suppression is obtained by resonant coupling with high index elements in the cladding. The temperature distribution on the fiber...... cross-section is calculated with an analytical model, for different pump power values. The consequent refractive index change, due to the thermo-optical effect, is applied to the cross-section of the DMF fiber, whose guiding properties are studied with a full-vector modal solver based on the finite...

  19. Antiplasticization and plasticization of Matrimid® asymmetric hollow fiber membranes—Part A. Experimental

    KAUST Repository

    Lee, Jong Suk

    2010-03-15

    The complex effects of highly sorbing feed gas contaminants such as toluene and n-heptane on performance of both annealed and non-annealed Matrimid® asymmetric fibers relevant to CO2/CH4 separation are reported. Membrane performance was quantified both during contaminant exposure and after removal of the contaminant from the feed stream. Exposure to either toluene or n-heptane during permeation reduces carbon dioxide permeance and the carbon dioxide/methane selectivity in non-annealed fibers. After exchange with a contaminant-free feed containing only CO2 and CH4 mixed gas, the carbon dioxide permeance and carbon dioxide/methane selectivity were affected, indicating a glassy state conditioning effect due to the prior contaminant exposure. Interestingly, the conditioning effect after simultaneous exposure to toluene and n-heptane (284 ppm toluene and 504 ppm n-heptane) was less than the conditioning observed for either toluene (293 ppm) or n-heptane (505 ppm) individually. Sub-Tg annealing reduced carbon dioxide permeance during actual contaminant exposure more severely than in non-annealed fibers. On the other hand, except for exposure to the highest n-heptane contaminant feed (2003 ppm), annealing significantly reduced the post-exposure conditioning observed in carbon dioxide permeance and carbon dioxide/methane selectivity. It appears that annealing allows the consolidation of segmental packing which stabilized the glassy matrix against swelling. At sufficiently high activities of even a relatively non-interacting penetrant like n-heptane, the annealing-induced stabilization can be reversed. © 2010 Elsevier B.V. All rights reserved.

  20. Design of a polarized filtering photonic-crystal fiber with gold-coated air holes.

    Science.gov (United States)

    Wang, Guangyao; Li, Shuguang; An, Guowen; Wang, Xinyu; Zhao, Yunyan; Zhang, Wan

    2015-10-20

    A novel design of a gold-coated photonic-crystal fiber (PCF) is studied by using the finite element method. The cross-section structure of the PCF is composed of a square lattice of air holes in which two air holes are gold coated, and the air-hole layout is modified. The resonance strength and the impact of structural parameters of the PCF on the polarization filter characteristics are studied. Numerical results show that the resonance strength and wavelengths are different in two polarized directions. The resonance strengths that we obtain can reach a value of 720 dB/cm at the wavelength of 1.31 μm. When the fiber length is 400 μm, the crosstalk can reach a value of 247.2 dB at the wavelength of 1.31 μm, which can be applied in many polarization filter devices. And when the length of fiber is longer than 200 μm, the crosstalk is better than 20 dB with wavelength ranges from 1.2 to 2 μm. Meanwhile, we can realize the filtering effect with a very short fiber.

  1. Suppression of high order modes employing active self-imaging mode filter in large mode area strongly pumped fiber amplifier

    Science.gov (United States)

    Zhao, Xiang; Bai, Gang; Zheng, Ye; Chen, Xiaolong; Yang, Yifeng; Qi, Yunfeng; He, Bing; Zhou, Jun

    2017-10-01

    To suppress high order modes and improve the beam quality, an active self-imaging mode filter based on multimode interference and self-imaging effect is proposed in large mode area (LMA) fiber amplifier. With this filter structure, transverse mode competition and individual transverse mode power distributions in strongly pumped fiber amplifiers are theoretically demonstrated. Employing this mode selection technique in 30/400 LMA strongly pumped fiber amplifier, the percentage of the fundamental mode rises from 27.8% (without filter) to 96.3%. By the modal power decomposition, the M2 parameter of beam quality decrease dramatically from 2.24 to 1.11 (0 relative phase) and from 3.01 to 1.24 (π/2 relative phase). This study provides a new method to achieve single mode in LMA fiber amplifier and this filter would be extended to larger mode area fiber amplifier to improve the beam quality.

  2. Characterization of mid-infrared emissions from C2H2, CO, CO2, and HCN-filled hollow fiber lasers

    Science.gov (United States)

    Jones, A. M.; Fourcade-Dutin, C.; Mao, C.; Baumgart, B.; Nampoothiri, A. V. V.; Campbell, N.; Wang, Y.; Benabid, F.; Rudolph, W.; Washburn, B. R.; Corwin, K. L.

    2012-02-01

    We have now demonstrated and characterized gas-filled hollow-core fiber lasers based on population inversion from acetylene (12C2H2) and HCN gas contained within the core of a kagome-structured hollow-core photonic crystal fiber. The gases are optically pumped via first order rotational-vibrational overtones near 1.5 μm using 1-ns pulses from an optical parametric amplifier. Transitions from the pumped overtone modes to fundamental C-H stretching modes in both molecules create narrow-band laser emissions near 3 μm. High gain resulting from tight confinement of the pump and laser light together with the active gas permits us to operate these lasers in a single pass configuration, without the use of any external resonator structure. A delay between the emitted laser pulse and the incident pump pulse has been observed and is shown to vary with pump pulse energy and gas pressure. Furthermore, we have demonstrated lasing beyond 4 μm from CO and CO2 using silver-coated glass capillaries, since fused silica based fibers do not transmit in this spectral region and chalcogenide fibers are not yet readily available. Studies of the laser pulse energy as functions of the pump pulse energy and gas pressure were performed. Efficiencies reaching ~ 20% are observed for both acetylene and CO2.

  3. Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

    Science.gov (United States)

    Kwon, Young-Nam; Kim, In-Chul

    2013-11-01

    Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

  4. Olefins-selective asymmetric carbon molecular sieve hollow fiber membranes for hybrid membrane-distillation processes for olefin/paraffin separations

    KAUST Repository

    Xu, Liren

    2012-12-01

    In this paper, the development of asymmetric carbon molecular sieve (CMS) hollow fiber membranes and advanced processes for olefin/paraffin separations based on the CMS membranes are reported. Membrane-based olefin/paraffin separations have been pursued extensively over the past decades. CMS membranes are promising to exceed the performance upper bound of polymer materials and have demonstrated excellent stability for gas separations. Previously, a substructure collapse phenomenon was found in Matrimid ® precursor derived CMS fiber. To overcome the permeance loss due to the increased separation layer thickness, 6FDA-DAM and 6FDA/BPDA-DAM precursors were selected as potential new precursors for carbon membrane formation. Defect-free asymmetric 6FDA-DAM and 6FDA/BPDA-DAM hollow fibers were successfully fabricated from a dry-jet/wet-quench spinning process. Polymer rigidity, glass-rubber transition and asymmetric morphology were correlated. CMS hollow fiber membranes produced from 6FDA-polymer precursors showed significant improvement in permeance for ethylene/ethane and propylene/propane separations. Further studies revealed that the CMS membranes are olefins-selective, which means the membranes are able to effectively separate olefins (ethylene and propylene) from paraffins (ethane and propane). This unique feature of CMS materials enables advanced hybrid membrane-distillation process designs. By using the olefins-selective membranes, these new processes may provide advantages over previously proposed retrofitting concepts. Further applications of the membranes are explored for hydrocarbons processes. Significant energy savings and even reduced footprint may be achieved in olefins production units. © 2012 Elsevier B.V.

  5. Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid

    Directory of Open Access Journals (Sweden)

    Abdulrahman Bahrami

    2017-02-01

    Full Text Available This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L−1 sodium chloride, liquid membrane containing 1-octanol with 20% (w/v tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL−1 were obtained. The relative standard deviation (RSD (% values for intra- and inter-day precisions were calculated at 2.5%–8.2% and 4.1%–10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens.

  6. Effects of wavelength filtering on pulse dynamics in a tunable, actively Q-switched fiber laser

    Science.gov (United States)

    Srivastava, Manas; Venkitesh, Deepa; Srinivasan, Balaji

    2018-01-01

    We present a numerical simulation, validated by experimental analysis, of the effect of wavelength filtering on pulse dynamics of a wavelength-tunable Erbium-doped fiber Q-switched laser in a ring configuration. Travelling wave time-dependent model is implemented using finite difference time domain (FDTD) method to accurately simulate the population dynamics and the pulse evolution in the ring laser. Such a model is experimentally validated for a wavelength tunable Q-switched fiber laser and stable Q-switched pulses are obtained over a wavelength tuning range of ∼30 nm in the C-band.

  7. Hollow Fiber Space Water Membrane Evaporator Flight Prototype Design and Testing

    Science.gov (United States)

    Bue, Grant C.; Makinen, Janice; Vogel, Mtthew; Honas, Matt; Dillon, Paul; Colunga, Aaron; Truong, Lily; Porwitz, Darwin; Tsioulos, Gus

    2011-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform thermal control for advanced spacesuits and to take advantage of recent advances in micropore membrane technology. This results in a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. The current design was based on a previous design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape. This was developed into a full-scale prototype consisting of 14,300 tube bundled into 30 stacks, each of which is formed into a chevron shape and separated by spacers and organized into three sectors of 10 nested stacks. The new design replaced metal components with plastic ones, eliminated the spacers, and has a custom built flight like backpressure valve mounted on the side of the SWME housing to reduce backpressure when fully open. A number of tests were performed in order to improve the strength of the polyurethane header that holds the fibers in place while the system is pressurized. Vacuum chamber testing showed similar heat rejection as a function of inlet water temperature and water vapor backpressure was similar to the previous design. Other tests pushed the limits of tolerance to freezing and showed suitability to reject heat in a Mars pressure environment with and without a sweep gas. Tolerance to contamination by constituents expected to be found in potable water produced by distillation processes was tested in a conventional way by allowing constituents to accumulate in the coolant as evaporation occurs. For this purpose, the SWME cartridge has endured an equivalent of 30 EVAs exposure and demonstrated acceptable performance decline.

  8. Obtaining absorption spectra from single textile fibers using a liquid crystal tunable filter microspectrophotometer.

    Science.gov (United States)

    Markstrom, Luke J; Mabbott, Gary A

    2011-06-15

    Visible absorption spectra were recorded for single textile fibers using a microspectrophotometer based on a liquid crystal tunable filter. Spectra compared well with results from a conventional instrument. Some advantages include very fast and simple sample preparation and easy comparison of multiple fibers at the same time. Advantages over extraction-dependent methods include the fact that it is applicable to extremely small sample size, not susceptible to artifacts induced by variable extraction efficiencies, non-destructive, and much easier. Because an immense amount of information is collected in one experiment, good signal averaging is possible, along with multiple comparisons for each data set. The addition of a camera, computer, and liquid crystal tunable filter can transform a standard microscope into a microspectrophotometer capable of performing similar work. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Pyrosequencing analysis of microbial communities in hollow fiber-membrane biofilm reactors system for treating high-strength nitrogen wastewater.

    Science.gov (United States)

    Park, Jung-Hun; Choi, Okkyoung; Lee, Tae-Ho; Kim, Hyunook; Sang, Byoung-In

    2016-11-01

    Wastewaters from swine farms, nitrogen-dealing industries or side-stream processes of a wastewater treatment plant (e.g., anaerobic digesters, sludge thickening processes, etc.) are characterized by low C/N ratios and not easily treatable. In this study, a hollow fiber-membrane biofilm reactors (HF-MBfR) system consisting of an O2-based HF-MBfR and an H2-based HF-MBfR was applied for treating high-strength wastewater. The reactors were continuously operated with low supply of O2 and H2 and without any supply of organic carbon for 250 d. Gradual increase of ammonium and nitrate concentration in the influent showed stable and high nitrogen removal efficiency, and the maximum ammonium and nitrate removal rates were 0.48 kg NH4(+)-N m(-3) d(-1) and 0.55 kg NO3(-)-N m(-3) d(-1), respectively. The analysis of the microbial communities using pyrosequencing analysis indicated that Nitrosospira multiformis, ammonium-oxidizing bacteria, and Nitrobacter winogradskyi and Nitrobacter vulgaris, nitrite-oxidizing bacteria were highly enriched in the O2-based HF-MBfR. In the H2-based HF-MBfR, hydrogenotrophic denitrifying bacteria belonging to the family of Thiobacillus and Comamonadaceae were initially dominant, but were replaced to heterotrophic denitrifiers belonging to Rhodocyclaceae and Rhodobacteraceae utilizing by-products induced from autotrophic denitrifying bacteria. The pyrosequencing analysis of microbial communities indicates that the autotrophic HF-MBfRs system well developed autotrophic nitrifying and denitrifying bacteria within a relatively short period to accomplish almost complete nitrogen removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Strategic Regulatory Evaluation and Endorsement of the Hollow Fiber Tuberculosis System as a Novel Drug Development Tool.

    Science.gov (United States)

    Romero, Klaus; Clay, Robert; Hanna, Debra

    2015-08-15

    The first nonclinical drug development tool (DDT) advanced by the Critical Path to TB Drug Regimens (CPTR) Initiative through a regulatory review process has been endorsed by leading global regulatory authorities. DDTs with demonstrated predictive accuracy for clinical and microbiological outcomes are needed to support decision making. Regulatory endorsement of these DDTs is critical for drug developers, as it promotes confidence in their use in Investigational New Drug and New Drug Application filings. The in vitro hollow fiber system model of tuberculosis (HFS-TB) is able to recapitulate concentration-time profiles (exposure) observed in patients for single drugs and combinations, by evaluating exposure measures for the ability to kill tuberculosis in different physiologic conditions. Monte Carlo simulations make this quantitative output useful to inform susceptibility breakpoints, dosage, and optimal combination regimens in patients, and to design nonclinical experiments in animal models. The Pre-Clinical and Clinical Sciences Working Group within CPTR executed an evidence-based evaluation of the HFS-TB for predictive accuracy. This extensive effort was enabled through the collaboration of subject matter experts representing the pharmaceutical industry, academia, product development partnerships, and regulatory authorities including the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). A comprehensive analysis plan following the regulatory guidance documents for DDT qualification was developed, followed by individual discussions with the FDA and the EMA. The results from the quantitative analyses were submitted to both agencies, pursuing regulatory DDT endorsement. The EMA Qualification Opinion for the HFS-TB DDT was published 26 January 2015 (available at: http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/document_listing/document_listing_000319.jsp). © The Author 2015. Published by Oxford University Press on behalf of the

  11. Periodic harvesting of embryonic stem cells from a hollow-fiber membrane based four-compartment bioreactor.

    Science.gov (United States)

    Knöspel, Fanny; Freyer, Nora; Stecklum, Maria; Gerlach, Jörg C; Zeilinger, Katrin

    2016-01-01

    Different types of stem cells have been investigated for applications in drug screening and toxicity testing. In order to provide sufficient numbers of cells for such in vitro applications a scale-up of stem cell culture is necessary. Bioreactors for dynamic three-dimensional (3D) culture of growing cells offer the option for culturing large amounts of stem cells at high densities in a closed system. We describe a method for periodic harvesting of pluripotent stem cells (PSC) during expansion in a perfused 3D hollow-fiber membrane bioreactor, using mouse embryonic stem cells (mESC) as a model cell line. A number of 100 × 10(6) mESC were seeded in bioreactors in the presence of mouse embryonic fibroblasts (MEF) as feeder cells. Over a cultivation interval of nine days cells were harvested by trypsin perfusion and mechanical agitation every second to third culture day. A mean of 380 × 10(6) mESC could be removed with every harvest. Subsequent to harvesting, cells continued growing in the bioreactor, as determined by increasing glucose consumption and lactate production. Immunocytochemical staining and mRNA expression analysis of markers for pluripotency and the three germ layers showed a similar expression of most markers in the harvested cells and in mESC control cultures. In conclusion, successful expansion and harvesting of viable mESC from bioreactor cultures with preservation of sterility was shown. The present study is the first one showing the feasibility of periodic harvesting of adherent cells from a continuously perfused four-compartment bioreactor including further cultivation of remaining cells. © 2015 American Institute of Chemical Engineers.

  12. Preparation of Sulfobetaine-Grafted PVDF Hollow Fiber Membranes with a Stably Anti-Protein-Fouling Performance

    Directory of Open Access Journals (Sweden)

    Qian Li

    2014-04-01

    Full Text Available Based on a two-step polymerization method, two sulfobetaine-based zwitterionic monomers, including 3-(methacryloylamino propyl-dimethyl-(3-sulfopropyl ammonium hydroxide (MPDSAH and 2-(methacryloyloxyethyl ethyl-dimethyl-(3-sulfopropyl ammonium (MEDSA, were successfully grafted from poly(vinylidene fluoride (PVDF hollow fiber membrane surfaces in the presence of N,N′-methylene bisacrylamide (MBAA as a cross-linking agent. The mechanical properties of the PVDF membrane were improved by the zwitterionic surface layers. The surface hydrophilicity of PVDF membranes was significantly enhanced and the polyMPDSAH-g-PVDF membrane showed a higher hydrophilicity due to the higher grafting amount. Compared to the polyMEDSA-g-PVDF membrane, the polyMPDSAH-g-PVDF membrane showed excellent significantly better anti-protein-fouling performance with a flux recovery ratio (RFR higher than 90% during the cyclic filtration of a bovine serum albumin (BSA solution. The polyMPDSAH-g-PVDF membrane showed an obvious electrolyte-responsive behavior and its protein-fouling-resistance performance was improved further during the filtration of the protein solution with 100 mmol/L of NaCl. After cleaned with a membrane cleaning solution for 16 days, the grafted MPDSAH layer on the PVDF membrane could be maintain without any chang; however, the polyMEDSA-g-PVDF membrane lost the grafted MEDSA layer after this treatment. Therefore, the amide group of sulfobetaine, which contributed significantly to the higher hydrophilicity and stability, was shown to be imperative in modifying the PVDF membrane for a stable anti-protein-fouling performance via the two-step polymerization method.

  13. Adipogenesis of Human Adipose-Derived Stem Cells Within Three-Dimensional Hollow Fiber-Based Bioreactors

    Science.gov (United States)

    Gerlach, Jörg C.; Lin, Yen-Chih; Brayfield, Candace A.; Minteer, Danielle M.; Li, Han; Rubin, J. Peter

    2012-01-01

    To further differentiate adipose-derived stem cells (ASCs) into mature adipocytes and create three-dimensional (3D) adipose tissue in vitro, we applied multicompartment hollow fiber-based bioreactor technology with decentral mass exchange for more physiological substrate gradients and integral oxygenation. We hypothesize that a dynamic 3D perfusion in such a bioreactor will result in longer-term culture of human adipocytes in vitro, thus providing metabolically active tissue serving as a diagnostic model for screening drugs to treat diabetes. ASCs were isolated from discarded human abdominal subcutaneous adipose tissue and then inoculated into dynamic 3D culture bioreactors to undergo adipogenic differentiation. Insulin-stimulated glucose uptake from the medium was assessed with and without TNF-alpha. 3D adipose tissue was generated in the 3D-bioreactors. Immunohistochemical staining indicated that 3D-bioreactor culture displayed multiple mature adipocyte markers with more unilocular morphologies as compared with two-dimensional (2D) cultures. Results of real-time polymerase chain reaction showed 3D-bioreactor treatment had more efficient differentiation in fatty acid-binding protein 4 expression. Repeated insulin stimulation resulted in increased glucose uptake, with a return to baseline between testing. Importantly, TNF-alpha inhibited glucose uptake, an indication of the metabolic activity of the tissue. 3D bioreactors allow more mature adipocyte differentiation of ASCs compared with traditional 2D culture and generate adipose tissue in vitro for up to 2 months. Reproducible metabolic activity of the adipose tissue in the bioreactor was demonstrated, which is potentially useful for drug discovery. We present here, to the best of our knowledge for the first time, the development of a coherent 3D high density fat-like tissue consisting of unilocular structure from primary adipose stem cells in vitro. PMID:21902468

  14. Thermo-responsive poly(N-isopropylacrylamide)-grafted hollow fiber membranes for osteoblasts culture and non-invasive harvest

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Meiling, E-mail: zhuangmeiling2006@126.com; Liu, Tianqing, E-mail: liutq@dlut.edu.cn; Song, Kedong, E-mail: kedongsong@dlut.edu.cn; Ge, Dan, E-mail: gedan@dlut.edu.cn; Li, Xiangqin, E-mail: xiangqinli@163.com

    2015-10-01

    Hollow fiber membrane (HFM) culture system is one of the most important bioreactors for the large-scale culture and expansion of therapeutic cells. However, enzymatic and mechanical treatments are traditionally applied to harvest the expanded cells from HFMs, which inevitably causes harm to the cells. In this study, thermo-responsive cellulose acetate HFMs for cell culture and non-invasive harvest were prepared for the first time via free radical polymerization in the presence of cerium (IV). ATR-FTIR and elemental analysis results indicated that the poly(N-isopropylacrylamide) (PNIPAAm) was covalently grafted on HFMs successfully. Dynamic contact angle measurements at different temperatures revealed that the magnitude of volume phase transition was decreased with increasing grafted amount of PNIPAAm. And the amount of serum protein adsorbed on HFMs surface also displayed the same pattern. Meanwhile osteoblasts adhered and spread well on the surface of PNIPAAm-grafted HFMs at 37 °C. And Calcein-AM/PI staining, AB assay, ALP activity and OCN protein expression level all showed that PNIPAAm-grafted HFMs had good cell compatibility. After incubation at 20 °C for 120 min, the adhering cells on PNIPAAm-grafted HFMs turned to be round and detached after being gently pipetted. These results suggest that thermo-responsive HFMs are attractive cell culture substrates which enable cell culture, expansion and the recovery without proteolytic enzyme treatment for the application in tissue engineering and regenerative medicine. - Highlights: • PNIPAAm-grafted HFMs exhibited thermoresponsive characteristic. • The OB cells could adhere and spread well on the surface of PNIPAAm-grafted HFMs. • PNIPAAm-grafted HFMs do not significantly impact ALP activity and OCN protein expression level of OB cells. • Cell could be detached from PNIPAAm-grafted HFMs when temperature decreased from 37 °C to 20 °C.

  15. Versatile, ultra-low sample volume gas analyzer using a rapid, broad-tuning ECQCL and a hollow fiber gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Kriesel, Jason M.; Makarem, Camille N.; Phillips, Mark C.; Moran, James J.; Coleman, Max; Christensen, Lance; Kelly, James F.

    2017-05-05

    We describe a versatile mid-infrared (Mid-IR) spectroscopy system developed to measure the concentration of a wide range of gases with an ultra-low sample size. The system combines a rapidly-swept external cavity quantum cascade laser (ECQCL) with a hollow fiber gas cell. The ECQCL has sufficient spectral resolution and reproducibility to measure gases with narrow features (e.g., water, methane, ammonia, etc.), and also the spectral tuning range needed to measure volatile organic compounds (VOCs), (e.g., aldehydes, ketones, hydrocarbons), sulfur compounds, chlorine compounds, etc. The hollow fiber is a capillary tube having an internal reflective coating optimized for transmitting the Mid-IR laser beam to a detector. Sample gas introduced into the fiber (e.g., internal volume = 0.6 ml) interacts strongly with the laser beam, and despite relatively modest path lengths (e.g., L ~ 3 m), the requisite quantity of sample needed for sensitive measurements can be significantly less than what is required using conventional IR laser spectroscopy systems. Example measurements are presented including quantification of VOCs relevant for human breath analysis with a sensitivity of ~2 picomoles at a 1 Hz data rate.

  16. Thermal Effects on the Single-Mode Regime of Distributed Modal Filtering Rod Fiber

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Alkeskjold, Thomas Tanggaard

    2012-01-01

    Power scaling of fiber laser systems requires the development of innovative active fibers, capable of providing high pump absorption, ultralarge effective area, high-order mode suppression, and resilience to thermal effects. Thermally induced refractive index change has been recently appointed...... as one major limitation to the achievable power, causing degradation of the modal properties and preventing to obtain stable diffraction-limited output beam. In this paper, the effects of thermally induced refractive index change on the guiding properties of a double-cladding distributed modal filtering...... rod-type photonic crystal fiber, which exploits resonant coupling with high-index elements to suppress high-order modes, are thoroughly investigated. A computationally efficient model has been developed to calculate the refractive index change due to the thermo-optical effect, and it has been...

  17. An improved hollow fiber solvent-stir bar microextraction for the preconcentration of anabolic steroids in biological matrix with determination by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Liu, Wei; Zhang, Lan; Fan, Liangbiao; Lin, Zian; Cai, Yimin; Wei, Zhenyi; Chen, Guonan

    2012-04-13

    In this paper, a convenient and self-assembled hollow fiber solvent-stir bar microextraction (HF-SSBME) device was developed, which could stir by itself. In the extraction process, the proposed device made the solvent "bar" not floating at the sample solution and exposing to air while organic solvents outside hollow fiber always wrapped with donor phase solvent, which reduced the vaporization of organic solvents. This design could improve the precisions and recoveries of experiments. For evaluating the device, seven anabolic steroids (prasterone, 5α-androstane-3α, 17β-diol, methandriol, 19-norandrostenediol, androstenediol, methyltestosterone and methandienone) were used as model analytes and extraction conditions such as type and volume of organic solvents, agitation speed, extraction time, extraction temperature and salt addition were studied in detail. Under the optimum conditions (15 μL toluene, 40 °C, stirring at 750 rpm for 30 min with 1.5 g sodium chloride addition in 20.0 mL donor phase), the linear ranges of anabolic steroids were 0.25-200 ng mL(-1) with gas chromatography-mass spectrometry. The limits of detection were lower than 0.10 ng mL(-1). The recoveries and precisions in spiked urine and hair samples were between 73.97-93.56% and 2.18-4.47% (n=5). HF-SSBME method combined the intrinsical merits of hollow fiber with the superiority of the proposed self-stirring device which can be developed to two-phase, three-phase and in situ derivatization modes with wide prospect of application. Besides, the pedestal of this proposed device can be converted to fix stir bar in stir bar sorptive extraction (SBSE) method. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Determination of total thyroxine in human serum by hollow fiber liquid-phase microextraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yong, Sharon; Chen, Yizhao; Lee, Tong Kooi; Lee, Hian Kee

    2014-08-01

    Determination of total thyroxine in human serum using hollow fiber liquid-phase microextraction (HF-LPME) has been accomplished for the first time. HF-LPME serves as an inexpensive sample pretreatment and the cleanup method that is nearly solvent-free. Thyroxine was extracted through a water immiscible organic solvent immobilized in the wall pores of a polypropylene hollow fiber into 20μl of an aqueous acceptor phase inside the lumen of the hollow fiber. This technique produced extracts that had comparable cleanness with those obtained using solid-phase extraction (SPE). Serum samples with endogenous thyroxine were spiked with isotopically-labeled thyroxine and analyzed by liquid chromatography-tandem mass spectrometry after HF-LPME extraction. Extraction parameters including the organic phase, acid/base concentration of acceptor phase, stirring speed and extraction time were optimized. The calibration range was found to be linear over 1-1000ng/g with the limit of detection (LOD) of 0.3 ng/g. For quantification of total thyroxine in human serum, 6 subsamples were prepared and the results indicated very good precision with a relative standard deviation of human serum were analyzed, and our obtained values were compared with the reference values. The results showed very good precision with RSD around 0.2% and the deviation from the reference values were -3.1% and -2.1%. The newly developed method is precise, accurate, inexpensive, and environmentally friendly. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Development of hollow fiber-supported liquid-phase microextraction and HPLC-DAD method for the determination of pyrethroid metabolites in human and rat urine.

    Science.gov (United States)

    Bartosz, Wielgomas; Marcin, Wiśniewski; Wojciech, Czarnowski

    2014-05-01

    A simple hollow fiber liquid-phase microextraction method for the determination of synthetic pyrethroid metabolites, 3-phenoxybenzoic acid and 4-hydroxy-3-phenoxybenzoic acid, in human and rat urine was developed and validated. A polypropylene hollow fiber tightly fitted onto a Nylon rod and impregnated with organic solvent served as a disposable extraction device. Desorption of analytes was carried out in NaOH solution, analyzed further by gradient HPLC and diode array detection method. Important factors were identified using Taguchi OA16 (4(5) ) orthogonal array design and further optimized using univariate approach. The optimum method performance was observed when 1 mL of urine hydrolyzed with 0.2 mL of concentrated HCl was further supplemented with 100 mg of NaCl and extracted for 120 min into dihexyl ether immobilized in the pores of the hollow fiber. Metabolites were desorbed into 0.1 mL of 0.1 M NaOH for another 120 min. Limits of detection and quantitation of 15 and 50 ng/mL were obtained for both analytes. Relative standard deviations of 1.6-12.6% over the linear range (50-10,000 ng/mL, r > 0.9906) were observed. Intra- and inter-day accuracies of the method ranged from 98.3 to 109.5% and from 93.3 to 110.9%, respectively. The optimized method was applied to the analysis of real urine samples collected from rats exposed orally to cypermethrin. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Thermal-Induced Refractive Index Change Effects on Distributed Modal Filtering Properties of Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Coscelli, E.; Poli, Federica; Jørgensen, Mette Marie

    2012-01-01

    The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature.......The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature....

  1. Ultra broadband UV generation by stimulated Raman scattering of two-color KrF laser in deuterium confined in a hollow fiber.

    Science.gov (United States)

    Takahashi, Eiichi; Kato, Susumu; Matsumoto, Yuji; Losev, Leonid L

    2007-03-05

    Broad Raman-multi-frequency spectra were generated from the resonant two-color excitation of the deuterium molecule rotational Raman transition (J=0?2), using ultraviolet bi-harmonic lasers with a quartz hollow fiber. Fifty pure rotational Raman spectral lines (34 lines that have intensity within 10% of the strongest spectral line) from 230 to 290 nm were generated at a gas pressure of 30 kPa. Furthermore, vibrational-rotational Raman spectral lines of almost 300 lines from 220 to 600 nm were also generated by increasing the gas pressure to 60 kPa.

  2. Automatic tunable and reconfigurable fiberoptic microwave filters based on a broadband optical source sliced by uniform fiber Bragg gratings.

    Science.gov (United States)

    Mora, J; Ortega, Beatriz; Capmany, J; Cruz, J; Andres, M; Pastor, D; Sales, S

    2002-11-04

    We demonstrate an automatic tunable transversal notch filter based on uniform fiber Bragg gratings and a broadband optical source. High tunability can be performed by stretching the fiber with the gratings written in series. Also, high sidelobe supression can be achieved by introducing tunable attenuators in a parallel configuration of the gratings.

  3. Enhanced fouling by inorganic and organic foulants on pressure retarded osmosis (PRO) hollow fiber membranes under high pressures

    KAUST Repository

    Chen, Sicong

    2015-04-01

    We have studied, for the first time, the fouling behavior of pressure retarded osmosis (PRO) hollow fiber membranes under low, moderate and high hydraulic pressures. The thin film composite (TFC) polyethersulfone (PES) membrane has a high water permeability and good mechanical strength. Membrane fouling by gypsum (CaSO4·2H2O) scalants, sodium alginate, and the combined foulants was examined under various pressures up to an ultrahigh hydraulic pressure of 18bar. In the combined fouling experiments, the membranes were conditioned by one of foulants followed by the other. Flux decline results suggested that such conditioning could increase the rate of combined fouling because of the change in membrane surface chemistry. Specially, the co-existence of gypsum crystals and alginate under 0bar led to the synergistic combined fouling and resulted in a greater flux decline than the sum of individual fouling. Interestingly, such gypsum-alginate synergistic fouling was not observed under high pressure PRO tests because the increased reverse salt flux inhibited the formation of gypsum crystals. Therefore, alginate fouling could be the dominant fouling mechanism for both (1) alginate conditioning and then scalants fouling, and (2) scalants conditioning and then alginate fouling PRO processes under 8bar and 18bar. Since the reverse salt flux increases from 5.6±1.1g/m2h at 0bar to 74.3±9.7g/m2h at 8bar, and finally to 150.5±2.5g/m2h under 18bar, the reverse salt ions lead to substantial declines of normalized flux under 8bar and 18bar because the reverse sodium ions not only reduce the effective driving force across the PRO membrane but also induce a significant cake-enhanced sodium concentration polarization layer and facilitate alginate gelation near the membrane surface. Therefore, the removal of alginate type foulants from the feed water stream may become essential for the success of PRO processes under high pressures.

  4. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  5. Temperature sensing property of hollow-core photonic bandgap fiber filled with CdSe/ZnS quantum dots in an UV curing adhesive

    Science.gov (United States)

    Wang, Helin; Yang, Aijun

    2017-11-01

    A temperature sensor based on the hollow-core photonic bandgap fiber filled with the CdSe/ZnS QDs dissolved in an ultraviolet (UV) curing adhesive is reported. The sensor shows a linear variation of the photoluminescence (PL) peak wavelength for a temperature range from 40 °C to 140 °C, with a correlation factor of 0.99263 and a sensitivity of 0.05744 nm/°C. Although the peak intensity of emission spectrum increased exponentially with the temperature, a linear temperature-dependence result with a correlation factor of 0.99917 and a slope of 2.04 × 10-3 °C-1 can be obtained with a self-reference spectral intensity method. The linear variation characteristics of the peak wavelength and the self-reference intensity of PL spectrum indicates the designed fiber temperature sensor is feasible in the practical application.

  6. A high-flux polyimide hollow fiber membrane to minimize footprint and energy penalty for CO2 recovery from flue gas

    KAUST Repository

    Lively, Ryan P.

    2012-12-01

    Using a process-guided approach, a new 6FDA-based polyimide - 6FDA-DAM:DABA(4:1) - has been developed in the form of hollow fiber membranes for CO 2 recovery from post-combustion flue gas streams. Dense film studies on this polymer reveal a CO 2 permeability of 224 Barrers at 40°C at a CO 2 feed pressure of 10psia. The dense films exhibit an ideal CO 2/N 2 permselectivity of 20 at 40°C, which permits their use in a two-step counter-flow/sweep membrane process. Dry-jet, wet-quench, non-solvent-induced phase inversion spinning was used to create defect-free hollow fibers from 6FDA-DAM:DABA(4:1). Membranes with defect-free skin layers, approximately 415nm thick, were obtained with a pure CO 2 permeance of 520GPU at 30°C and an ideal CO 2/N 2 permselectivity of 24. Mixed gas permeation and wet gas permeation are presented for the fibers. The CO 2 permeance in the fibers was reduced by approximately a factor of 2 in feeds with 80% humidity. As a proof-of-concept path forward to increase CO 2 flux, we incorporated microporous ZIF-8 fillers into 6FDA-DAM:DABA(4:1) dense films. Our 6FDA-DAM:DABA(4:1)/ZIF-8 dense film composites (20wt% ZIF-8) had a CO 2 permeability of 550 Barrers and a CO 2/N 2 selectivity of 19 at 35°C. Good adhesion between the ZIF and the 6FDA-DAM:DABA(4:1) matrix was observed. CO 2 capture costs of $27/ton of CO 2 using the current, "non-optimized" membrane are estimated using a custom counterflow membrane model. Hollow fiber membrane modules were estimated to have order-of-magnitude reductions in system footprint relative to spiral-wound modules, thereby making them attractive in current space-constrained coal-fired power stations. © 2012 Elsevier B.V.

  7. Irreversible sorption of trace concentrations of perfluorocarboxylic acids to fiber filters used for air sampling

    Science.gov (United States)

    Arp, Hans Peter H.; Goss, Kai-Uwe

    Due to the apparent environmental omnipresence of perfluorocarboxylic acids (PFAs), an increasing number of researchers are investigating their ambient particle- and gas-phase concentrations. Typically this is done using a high-volume air sampler equipped with Quartz Fiber Filters (QFFs) or Glass Fiber Filters (GFFs) to sample the particle-bound PFAs and downstream sorbents to sample the gas-phase PFAs. This study reports that at trace, ambient concentrations gas-phase PFAs sorb to QFFs and GFFs irreversibly and hardly pass through these filters to the downstream sorbents. As a consequence, it is not possible to distinguish between particle- and gas-phase concentrations, or to distinguish concentrations on different particle size fractions, unless precautions are taken. Failure to take such precautions could have already caused reported data to be misinterpreted. Here it is also reported that deactivating QFFs and GFFs with a silylating agent renders them suitable for sampling PFAs. Based on the presented study, a series of recommendations for air-sampling PFAs are provided.

  8. Exploring nonlinear pulse propagation, Raman frequency conversion and near octave spanning supercontinuum generation in atmospheric air-filled hollow-core Kagomé fiber

    Science.gov (United States)

    Abokhamis Mousavi, Seyedmohammad; Mulvad, Hans Christian Hansen; Wheeler, Natalie; Horak, Peter; Bradley, Thomas D.; Alam, Shaif-ul; Hayes, John; Sandoghchi, Seyed Reza; Richardson, David; Poletti, Francesco

    2017-02-01

    We have demonstrated Raman frequency conversion and supercontinuum light generation in a hollow core Kagomé fiber filled with air at atmospheric pressure, and developed a numerical model able to explain the results with good accuracy. A solid-state disk laser was used to launch short pulses ( 6ps) at 1030nm into an in-house fabricated hollow core Kagomé fiber with negative core curvature and both ends were open to the atmosphere. The fiber had a 150 THz wide transmission window and a record low loss of 12 dB/km at the pump wavelength. By gradually increasing the pulse energy up to 250 μJ, we observed the onset of different Kerr and Raman based optical nonlinear processes, resulting in a supercontinuum spanning from 850 to 1600 nm at maximum input power. In order to study the pulse propagation dynamics of the experiment, we used a generalized nonlinear Schrödinger equation (GNLSE). Our simulations showed that the use of a conventional damping oscillator model for the time-dependent response of the rotational Raman component of air was not accurate enough at such high intensities and large pulse widths. Therefore, we adopted a semiquantum Raman model for air, which included the full rotational and vibrational response, and their temperature-induced broadening. With this, our GNLSE results matched well the experimental data, which allowed us to clearly identify the nonlinear phenomena involved in the process. Aside from the technological interest in the high spectral density of the supercontinuum demonstrated, the validated numerical model can provide a valuable optimization tool for gas based nonlinear processes in air-filled fibers.

  9. Bis(trifluoromethylsulfonyl)imide-based frozen ionic liquid for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites.

    Science.gov (United States)

    Pang, Long; Yang, Peijie; Pang, Rong; Li, Shunyi

    2017-08-01

    1-Hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide is a solid-phase ionic organic material under ambient temperature and is considered as a kind of "frozen" ionic liquid. Because of their solid-state and ultra-hydrophobicity, "frozen" ionic liquids are able to be confined in the pores of hollow fiber, based on which a simple method was developed for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites. Under optimized conditions, the proposed method results in good linearity (R(2) > 0.9965) over the range of 0.5-50 μg/L, with low limits of detection and quantification in the range of 0.33-0.38 and 1.00-1.25 μg/L, respectively. Intra- and interday precisions evaluated by relative standard deviation were 3-6 and 1-6%, respectively. The spiked recoveries of dichlorodiphenyltrichloroethane and its main metabolites from real water samples were in the range of 64-113 and 79-112%, respectively, at two different concentration levels. The results suggest that "frozen" ionic liquids are promising for use as a class of novel sorbents. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Investigation of antifouling and disinfection potential of chitosan coated iron oxide-PAN hollow fiber membrane using Gram-positive and Gram-negative bacteria.

    Science.gov (United States)

    Mukherjee, Munmun; De, Sirshendu

    2017-06-01

    Chitosan coated iron oxide nanoparticles were impregnated into polyacrylonitrile based hollow fiber membrane. The molecular weight cut off was varied in the range of 120 to 145kDa with the concentration of nanoparticles. Incorporation of nanoparticles improved the permeability, mechanical property and hydrophilicity of the membrane. The contact angle of the membrane decreased from 80° to 51° and the permeability increased by 31% at 0.5wt% nanoparticles concentration. The antibacterial and antifouling property of the membrane were investigated with two biofilm causing Gram positive and Gram negative bacteria. The damage of cell membrane was directly confirmed by release of cellular constituent absorbing in 260nm. The cellular deformation on the membrane surface was evident by direct microscopic observation in FESEM. This damage was likely caused by electrostatic interaction between NH3+ group of nanoparticles and anionic components of phosphoryl group of bacteria. The hollow fiber membrane shows promising antibiofouling property even after long experimental run as evident by 95% flux recovery ratio. The effect of operating conditions on rejection and flux profile was investigated during long experimental run. The result indicated that there was no detectable iron in the permeate sample that could impose adverse health hazard. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Analysis of amantadine in biological fluids using hollow fiber-based liquid-liquid-liquid microextraction followed by corona discharge ion mobility spectrometry.

    Science.gov (United States)

    Saraji, Mohammad; Khayamian, Taghi; Mirmahdieh, Shiva; Bidgoli, Ali Akbar Hajialiakbari

    2011-10-15

    A method based on liquid-liquid-liquid microextraction combined with corona discharge ion mobility spectrometry was developed for the analysis of amantadine in human urine and plasma samples. Amantadine was extracted from alkaline aqueous sample as donor phase through a thin phase of organic solvent (n-dodecane) filling the pores of the hollow fiber wall and then back extracted into the organic acceptor phase (methanol) located in the lumen of the hollow fiber. All variables affecting the extraction of analyte including acceptor organic solvent type, concentration of NaOH in donor phase, ionic strength of the sample and extraction time were studied. The linear range was 20-1000 and 5-250 ng/mL for plasma and urine, respectively (r(2)≥0.990). The limits of detection were calculated to be 7.2 and 1.6 ng/mL for plasma and urine, respectively. The relative standard deviation was lower than 8.2% for both urine and plasma samples. The enrichment factors were between 45 and 54. The method was successfully applied for the analysis of amantadine in urine and plasma samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Hollow fiber based liquid phase microextraction for the determination of organochlorine pesticides in ecological textiles by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Cai, Jin'an; Chen, Guosheng; Qiu, Junlang; Jiang, Ruifen; Zeng, Feng; Zhu, Fang; Ouyang, Gangfeng

    2016-01-01

    In this study, the hollow fiber-liquid phase microextraction (HF-LPME) coupled gas chromatograph/mass spectrometry (GC/MS) was firstly developed to determine 10 organochlorine pesticides (OCPs) in ecological textiles. The present method can offer high separation efficiencies with minimal sample and solvent consumption. The extraction conditions were optimized, including the types of hollow fiber and organic solvent, the extraction time, the stirring and the salinity. Under the optimized conditions, the linear ranges of OCPs in cotton, terylene and fur samples were 5-1000 ng/g, 10-1000 ng/g and 10-800 ng/g, respectively, and the detection limit of the three samples were 0.07-2.30 ng/g, 0.89-1.66 ng/g and 0.06-1.04 ng/g, respectively. The optimized method was then successfully used to determine the OCPs in 3 kinds of spiked real samples, including cotton, terylene and fur. The good recoveries and RSDs of the quantification in real textile samples were obtained and the results were confirmed by the traditional liquid extraction method (GB/T 18412-2006). This study proved that the HF-LPME method, which was simple, low-cost and virtually solvent-free, was reliable for the qualitative and quantitative analysis of the harmful OCP residues in ecological textiles. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Maghemite nanoparticle-decorated hollow fiber electromembrane extraction combined with dispersive liquid-liquid microextraction for determination of thymol from Carum copticum.

    Science.gov (United States)

    Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Bohlooli, Mousa; Barkhordar, Afsaneh; Ghaffari-Moghaddam, Mansour

    2017-03-01

    A novel technique using maghemite nanoparticle-decorated hollow fibers to assist electromembrane extraction is proposed. Electromembrane extraction combined with dispersive liquid-liquid microextraction (EME-DLLME) was applied for the extraction of thymol from Carum copticum, followed by gas chromatography with flame ionization detection (GC-FID). The use of maghemite nanoparticle-decorated hollow fibers was found to improve the extraction efficiency of thymol significantly. Important operational parameters, including pH of acceptor phase, extraction time, voltage and temperature, were investigated and optimized. At the optimal conditions, linearity in the range 4-1800 µg L-1 with a determination coefficient of 0.9996 was obtained. The limit of detection was 0.11 µg L-1 (S/N = 3) and the pre-concentration factor was 200. The intra- and inter-day precision was 5.9 and 2.2% respectively. The intra- and inter-day accuracy was higher than 93.6%. The results indicated that EME-DLLME/GC-FID is a useful technique for the extraction and determination of thymol in C copticum. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. Synthesis and application of a novel solid-phase microextraction adsorbent: hollow fiber supported carbon nanotube reinforced sol-gel for determination of phenobarbital.

    Science.gov (United States)

    Es'haghi, Zarrin; Rezaeifar, Zohreh; Rounaghi, Gholam-Hossein; Nezhadi, Zahra Alian; Golsefidi, Mazyar Ahmadi

    2011-03-09

    A novel solid-phase microextraction technique using a hollow fiber-supported sol-gel combined with multi-walled carbon nanotubes was employed in the determination of phenobarbital in wastewater. In this new technique, a silica-based, organic-inorganic polymer containing functionalized multi-walled carbon nanotubes (MWCNTs) was prepared with sol-gel technology via the reaction of tetraethylorthosilicate (TEOS) with an acidic catalyst (HCl). This sol was injected into a polypropylene hollow fiber segment for in situ gelation. This device operated in direct immersion sampling mode. The experimental setup is simple and affordable, and the device is disposable, so there is no risk of cross-contamination or carry-over. Parameters affecting extraction such as pH of the aqueous solution, ageing and extraction times, aqueous sample volume, agitation speed and carbon nanotube amount were optimized. Linearity was observed over a range of 0.50-5000 ng mL(-1), with an estimation coefficient (r(2)) higher than 0.982. The limit of detection (LOD) was 0.32 ng mL(-1) (n=5), and repeatability (RSD%=2.9) was from the average of three levels of analyte concentrations (1, 1000 and 4500 ng mL(-1)) with three replicates for each within a single day. Finally, a pre-concentration factor of 2100 was obtained for phenobarbital. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Characterization of silver halide fiber optics and hollow silica waveguides for use in the construction of a mid-infrared attenuated total reflection fourier transform infrared (ATR FT-IR) spectroscopy probe.

    Science.gov (United States)

    Damin, Craig A; Sommer, André J

    2013-11-01

    Advances in fiber optic materials have allowed for the construction of fibers and waveguides capable of transmitting infrared radiation. An investigation of the transmission characteristics associated with two commonly used types of infrared-transmitting fibers/waveguides for prospective use in a fiber/waveguide-coupled attenuated total internal reflection (ATR) probe was performed. Characterization of silver halide polycrystalline fiber optics and hollow silica waveguides was done on the basis of the transmission of infrared light using a conventional fiber optic coupling accessory and an infrared microscope. Using the fiber optic coupling accessory, the average percent transmission for three silver halide fibers was 18.1 ± 6.1% relative to a benchtop reflection accessory. The average transmission for two hollow waveguides (HWGs) using the coupling accessory was 8.0 ± 0.3%. (Uncertainties in the relative percent transmission represent the standard deviations.) Reduced transmission observed for the HWGs was attributed to the high numerical aperture of the coupling accessory. Characterization of the fibers/waveguides using a zinc selenide lens objective on an infrared microscope indicated 24.1 ± 7.2% of the initial light input into the silver halide fibers was transmitted. Percent transmission obtained for the HWGs was 98.7 ± 0.1%. Increased transmission using the HWGs resulted from the absence or minimization of insertion and scattering losses due to the hollow air core and a better-matched numerical aperture. The effect of bending on the transmission characteristics of the fibers/waveguides was also investigated. Significant deviations in the transmission of infrared light by the solid-core silver halide fibers were observed for various bending angles. Percent transmission greater than 98% was consistently observed for the HWGs at the bending angles. The combined benefits of high percent transmission, reproducible instrument responses, and increased bending

  16. Gas-self-filter-based erbium-doped fiber loop laser for gas detection.

    Science.gov (United States)

    Guo, Kaikai; Lou, Xiutao; Yan, Chunsheng; Mei, Liang

    2014-08-01

    An erbium-doped fiber (EDF) loop laser, based on a gas-self-filter (GSF), is developed with single or multiple wavelength emission. The GSF is a type of Mach-Zehnder interferometer with a gas cell in one arm. By matching the destructive wavelength of the interferometer with the gas absorption line, the self-filtering function is achieved. A GSF-based multi-wavelength laser with a side-mode suppression ratio of ~50  dB is performed. As an example, C₂H₂ gas is detected using a single-wavelength GSF-based laser with correlation spectroscopy, and a good linearity of the measurement is obtained. The present laser has the potential advantage for multiple gas detection, e.g., being free of wavelength calibration.

  17. Metals distribution on the surface of quartz fiber filters used for particulate matter collection

    Directory of Open Access Journals (Sweden)

    Widziewicz Kamila

    2015-12-01

    Full Text Available Presented study aimed to determine metals distribution on the quartz fiber filters surface coated with particulate matter by using high and low-volume samplers. The distribution pattern was tested using two different sub-sampling schemes. Each sub-sample was mineralized in the nitric acid in a microwave oven. An analysis was performed by means of atomic absorption spectroscopy with electrothermal atomization GF-AAS technique, and the determined elements were: As, Cd, Pb and Ni. A validation of the analytical procedure was carried out using NIES 28 Urban Aerosols standard reference material.

  18. Long fiber Bragg grating sensor interrogation using discrete-time microwave photonic filtering techniques.

    Science.gov (United States)

    Ricchiuti, Amelia Lavinia; Barrera, David; Sales, Salvador; Thevenaz, Luc; Capmany, José

    2013-11-18

    A novel technique for interrogating photonic sensors based on long fiber Bragg gratings (FBGs) is presented and experimentally demonstrated, dedicated to detect the presence and the precise location of several spot events. The principle of operation is based on a technique used to analyze microwave photonics (MWP) filters. The long FBGs are used as quasi-distributed sensors. Several hot-spots can be detected along the FBG with a spatial accuracy under 0.5 mm using a modulator and a photo-detector (PD) with a modest bandwidth of less than 1 GHz. The proposed interrogation system is intrinsically robust against environmental changes.

  19. Reconfigurable radio-over-fiber system based on optical switch and tunable filter

    Science.gov (United States)

    Li, Xiao; Yin, Rui; Ji, Wei; Sun, Kai; Zhang, Shicheng

    2017-09-01

    As the best candidate for wireless-access networks, radio-over-fiber (RoF) technology can carry a variety of business. It is necessary to provide differentiated services for different users, so the network needs to produce signals with different modulation formats and different frequencies. A reconfigurable RoF system based on a switch and tunable optical filter that can realize modulation format conversion and multiple frequency signal switching functions is designed. It has a good performance in terms of bit error rate and an eye diagram. The design can help to use radio frequency resources efficiently and make dynamic bandwidth resources controllable.

  20. Direct design of high channel-count fiber Bragg grating filters with low index modulation.

    Science.gov (United States)

    Cao, Hui; Atai, Javid; Shu, Xuewen; Chen, Guojie

    2012-05-21

    a novel method for designing high channel-count fiber Bragg gratings (FBGs) is proposed. For the first time, tailored group delay is introduced into the target reflection spectra to obtain a more even distribution of the refractive index modulation. This approach results in the reduction of the maximum refractive index modulation to physically realizable levels. The maximum index modulation reduction factors are all greater than 5.5. This is a significant improvement compared with previously reported results. Numerical results show that the thus designed high channel-count FBG filters exhibit superior characteristics including 30 dB channel isolation, a flat-top and near 100% reflectivity in each channel.

  1. MODELING REFLECTANCE AND TRANSMITTANCE OF QUARTZ-FIBER FILTER SAMPLES CONTAINING ELEMENTAL CARBON PARTICLES: IMPLICATIONS FOR THERMAL/OPTICAL ANALYSIS. (R831086)

    Science.gov (United States)

    A radiative transfer scheme that considers absorption, scattering, and distribution of light-absorbing elemental carbon (EC) particles collected on a quartz-fiber filter was developed to explain simultaneous filter reflectance and transmittance observations prior to and during...

  2. Tunable polarization filter based on high-birefringence photonic crystal fiber filled with silver wires

    Science.gov (United States)

    Yang, Xianchao; Lu, Ying; Liu, Baolin; Yao, Jianquan

    2017-07-01

    A tunable single polarization filter based on high-birefringence photonic crystal fiber with silver wires symmetrically filled into cladding air holes is designed. The confinement loss of the unwanted polarized mode (x-polarized mode) at 1310- and 1550-nm bands are 371 and 252 dB/cm, whereas another mode confinement loss (y-polarized mode) at the corresponding wavelength as low as 14 and 10 dB/cm, respectively. Moreover, the 20-dB bandwidth can reach 179 (at the 1310-nm band) and 71 nm (at the 1550-nm band) for a propagation distance of 1 mm. The dispersion relations and polarization characteristics are analyzed in detail utilizing the finite element method. Numerical results show that by adjusting the pitch between two adjacent air holes, the diameters of cladding air holes or silver wires near the fiber core, the resonance wavelength and resonance strength can be tuned effectively, which is beneficial for tunable polarization filter devices in the communication wave bands.

  3. Effects of millimeter wave carbon fibers on filter-feeding freshwater invertebrates.

    Science.gov (United States)

    Soucek, David J; Dickinson, Amy; Cropek, Donald M

    2010-05-01

    The purpose of our study was to investigate the sub-lethal effects of millimeter wave carbon fibers (MWCF), a military obscurant, on filter-feeding freshwater invertebrates. We observed decreased survival, reproduction, and oxygen consumption in Daphnia magna at realistic loading rates. In experiments with the Asiatic clam (Corbicula fluminea), soft tissue dry weight and tissue condition index were not significantly different among control and MWCF exposed treatments; however, using a (15)N labeled alga as food, we observed decreased nitrogen turnover in tissues of clams exposed to MWCF, suggesting lower filtering or ingestion rates. Our findings combined with previous demonstrations of MWCF toxicity to green algae suggest that over a period of several months, bivalve growth may be inhibited, and cladoceran populations may be even more strongly affected by MWCF. Given that these fibers are persistent, further experiments should be conducted to determine the longer-term effects of contamination of water bodies with MWCF. Copyright 2009 Elsevier Inc. All rights reserved.

  4. Radiological results for samples collected on paired glass- and cellulose-fiber filters at the Sandia complex, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Shadel, Craig A. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2016-03-01

    Airborne particulates are collected at U.S. Department of Energy sites that exhibit radiological contamination on the soil surface to help assess the potential for wind to transport radionuclides from the contamination sites. Collecting these samples was originally accomplished by drawing air through a cellulose-fiber filter. These filters were replaced with glass-fiber filters in March 2011. Airborne particulates were collected side by side on the two filter materials between May 2013 and May 2014. Comparisons of the sample mass and the radioactivity determinations for the side-by-side samples were undertaken to determine if the change in the filter medium produced significant results. The differences in the results obtained using the two filter types were assessed visually by evaluating the time series and correlation plots and statistically by conducting a nonparametric matched-pair sign test. Generally, the glass-fiber filters collect larger samples of particulates and produce higher radioactivity values for the gross alpha, gross beta, and gamma spectroscopy analyses. However, the correlation between the radioanalytical results for the glass-fiber filters and the cellulose-fiber filters was not strong enough to generate a linear regression function to estimate the glass-fiber filter sample results from the cellulose-fiber filter sample results.

  5. Design of a novel photonic crystal fiber filter based on gold-coated and elliptical air holes

    Science.gov (United States)

    Zhao, Yunyan; Li, Shuguang; Liu, Qiang; Wang, Xinyu

    2017-11-01

    In recent years, photonic crystal fibers have played an important role in the field of optical communications, and the addition of metal materials to photonic crystal fibers have offered new ways to improve the transmission characteristics of optical fibers. We design a new type of gold-coated photonic crystal filter, which utilizes the surface plasmon resonance effect, and study it by using the finite element method. In this paper, we optimise the structure parameters and analyze the numerical results. The numerical results show that the thickness of metal layer and the air holes near the fiber core strongly affect the performance of the polarization filter. For the operating wavelength of 1550 nm, the loss in the y-polarization direction can be as high as 906.9 dB/cm, which is much larger than the x-polarization direction. When the fiber length is longer than 100 μm, the crosstalk in the wavelength range from 1.4 μm to 1.9 μm is greater than 20 dB. The proposed optical fiber can find application as an optical fiber polarization filter.

  6. Toward the treatment for Alzheimer's disease: adsorption is primary mechanism of removing amyloid β protein with hollow-fiber dialyzers of the suitable materials, polysulfone and polymethyl methacrylate.

    Science.gov (United States)

    Kawaguchi, Kazunori; Saigusa, Akira; Yamada, Shinji; Gotoh, Takehiro; Nakai, Shigeru; Hiki, Yoshiyuki; Hasegawa, Midori; Yuzawa, Yukio; Kitaguchi, Nobuya

    2016-06-01

    The accumulation of amyloid β protein (Aβ) in the brain reflects cognitive impairment in Alzheimer's disease. We hypothesized that the rapid removal of Aβ from the blood by an extracorporeal system may act as a peripheral Aβ sink from the brain. The present study aimed to determine the optimal materials and modality for Aβ removal by hemodialyzers. In a batch analysis, hollow-fiber fragments of polysulfone (PSf) and polymethyl methacrylate (PMMA) showed greater removal efficiency of Aβ than did other materials, such as cellulose-triacetates and ethylene-vinyl alcohol copolymer (PSf:PMMA at 30 min, 98.6 ± 2.4 %:97.8 ± 0.4 % for Aβ1-40 and 96.6 ± 0.3 %:99.0 ± 1.0 % for Aβ1-42). In a modality study, the Aβ solution was applied to PSf dialyzers and circulated in the dialysis and Air-filled adsorption-mode (i.e., the outer space of the hollow fibers was filled with air) or phosphate-buffered saline (PBS)-filled adsorption modes. The Aβ1-40 removal efficiency of the pre/post dialyzer in the Air-filled adsorption-mode was the highest (62.4 ± 12.6 %, p = 0.007). In a flow rate study in the Air-filled adsorption-mode, 200 mL/min showed the highest Aβ1-40 reduction rate of pool solution (97.3 ± 0.8 % at 15 min) compared with 20 mL/min (p = 0.00001) and 50 mL/min (p = 0.00382). PMMA dialyzers showed similar high reduction rates. Thus, the optimal modality for Aβ removal was the adsorption-mode with PSf or PMMA hollow fibers at around 50 mL/min flow rate, which seems to be suitable for clinical use.

  7. Ionic liquid mediated sol-gel sorbents for hollow fiber solid-phase microextraction of pesticide residues in water and hair samples.

    Science.gov (United States)

    Ebrahimi, Mahmoud; Es'haghi, Zarrin; Samadi, Fatemeh; Hosseini, Mohammad-Saeid

    2011-11-18

    An ionic liquid mediated sol-gel sorbents for hollow fiber solid-phase microextraction (HF-SPME) was developed for extraction of the pesticides: diazinon, fenitrothion, malathion, fenvalerate, phosalone and tridemorph from human hair and water samples. The analytes were subsequently analyzed with high performance liquid chromatography and diode array detection (HPLC-DAD). Preliminary experiments were carried out in order to study experimental conditions for pesticides' extraction from spiked hair and water samples with HF-SPME using hollow fiber-supported ionic liquid mediated sol-gel sorbent. The sol-gel nanocomposites were reinforced with nanoparticles such as carboxylic functionalized multi-walled carbon nanotubes (COOH-MWCNTs), amino functionalized multi-walled carbon nanotubes (NH(2)-MWCNTs), nano SiO(2), nano TiO(2) and nano MgO comparatively to promote extraction efficiency. In this device, the innovative solid sorbents were developed by the sol-gel method via the reaction of tetraethylorthosilicate (TEOS) with 2-amino-2-hydroxymethyl-propane-1,3-diol (TRIS). In the basic condition (pH 10-11), the gel growth process in the presence of ionic liquid and nanoparticles was initiated. Then, the sol was injected into a polypropylene hollow fiber segment for in situ gelation process. Parameters affecting the efficiency of HF-SPME were thoroughly investigated. Linearity was observed over a range of 0.01-25,000 ng/mL with detection limits between 0.004 and 0.095 ng/mL for the pesticides in the aqueous matrices and 0.003-0.080 ng/mL in the hair matrices. The relative recoveries in the real samples ranged from 82.0% to 94.0% for the pesticides store seller's hair and the work researchers' hair. Results are showing the great possibilities of HF-SPME-HPLC-PDA for analysis of pesticides in biological and environmental samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Rapid determination of 54 pharmaceutical and personal care products in fish samples using microwave-assisted extraction-Hollow fiber-Liquid/solid phase microextraction.

    Science.gov (United States)

    Zhang, Yi; Guo, Wen; Yue, Zhenfeng; Lin, Li; Zhao, Fengjuan; Chen, Peijin; Wu, Weidong; Zhu, Hong; Yang, Bo; Kuang, Yanyun; Wang, Jiong

    2017-04-15

    In this paper, a simple, rapid, solvent-less and environmental friendliness microextraction method, microwave-assisted extraction-hollow fiber-liquid/solid phase microextraction (MAE-HF-L/SME), was developed for simultaneous extraction and enrichment of 54 trace hydrophilic/lipophilic pharmaceutical and personal care products (PPCPs) from fish samples. A solid-phase extraction material, solid-phase microextraction (SPME) fiber, was synthesized. The SPME fiber had a homogeneous, loose structure and good mechanical properties, and they exhibited a good adsorption capacity for most PPCPs selected. The material formed the basis for the method of MAE-HF-L/SME. A method of liquid chromatography-high resolution mass spectroscopy (LC-HRMS) for analysis of 54 PPCPs. Under optimal synthesis and extraction conditions, the limits of detection (LODs, n=3) and the limits of quantitation (LOQs, n=10) for the 54 PPCPs were between 0.01-0.50μg·kg-1 and 0.052.00μg·kg-1, respectively. Percent recoveries and the relative standard deviations (RSDs) in spiked fish samples (n=6) were between 56.3%-119.9% and 0.3%-17.1%, respectively. The microextraction process of 54 PPCPs in MAE-HF-L/SME took approximately 12min. The method has a low matrix interference and high enrichment factor and may be applicable for determination of 54 different PPCPs in fish samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Optical properties of NaLuF4: Yb3+: Tm3+/Ho3+ rare earth nanocrystals in microstructure hollow fiber

    Science.gov (United States)

    Zhang, Yundong; Li, Hui; Li, Hanyang; Wu, Yongfeng; Yu, Changqiu; Zhang, Tuo; Yuan, Ping

    2016-11-01

    In the present paper, we first demonstrate NaLuF4: Yb3+: Tm3+/Ho3+ rare earth nanocrystals in microstructure hollow fiber. An analysis of the intense blue upconversion emission at 450 and 475 nm in Tm3+/Yb3+ codoped NaLuF4 under excitation power 0.65W available from solid laser emitting at 980nm, has been undertaken. Fluorescence intensity ratio (FIR) variation of temperature-sensitive blue upconversion emission at 450and 475 nm in this material was recorded in the temperature range from 300 to 345 K. The maximum sensitivity derived from the FIR technique of the blue upconversion emission is approximately 0.005 K-1. The results imply that Tm3+/Yb3+ codoped NaLuF4 is a potential candidate for the optical temperature sensor.

  10. Hollow fiber liquid-phase microextraction-gas chromatography-mass spectrometry method to analyze bisphenol A and other plasticizer metabolites.

    Science.gov (United States)

    Fernandez, Miriany A Moreira; André, Leiliane Coelho; Cardeal, Zenilda de Lourdes

    2017-01-20

    Phthalates and bisphenol A are important environmental pollutants due to their toxicity for humans and animals, including actions in the endocrine system. Their metabolites in urine can be used as biomarkers to assess human exposure. This paper describes the development of a new method to determine bisphenol A and eight phthalate metabolites in urine samples using hollow fiber liquid phase microextraction (HF-LPME) and gas chromatography-mass spectrometry (GC-MS). This method showed linearity, precision, limits of detection, and quantification suitable to analyze these compounds at low concentration levels in urine. Limits of detection ranged from 0.777 to 23.3μgL-1, showing sensitivity for evaluating environmental exposure. Relative standard deviation (RSD) ranged from 11.7 to 19.7%. The developed method presented a good biomarker alternative for evaluating environmental exposure to bisphenol A and phthalates. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Syngas fermentation to biofuel: evaluation of carbon monoxide mass transfer and analytical modeling using a composite hollow fiber (CHF) membrane bioreactor.

    Science.gov (United States)

    Munasinghe, Pradeep Chaminda; Khanal, Samir Kumar

    2012-10-01

    In this study, the volumetric mass transfer coefficients (Ka) for CO were examined in a composite hollow fiber (CHF) membrane bioreactor. The mass transfer experiments were conducted at various inlet gas pressures (from 5 to 30 psig (34.5-206.8 kPa(g))) and recirculation flow rates (300, 600, 900, 1200 and 1500 mL/min) through CHF module. The highest Ka value of 946.6 1/h was observed at a recirculation rate of 1500 mL/min and at an inlet gas pressure of 30 psig(206.8 kPa(g)). The findings of this study confirm that the use of CHF membranes is effective and improves the efficiency CO mass transfer into the aqueous phase. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Supercontinuum generation and tunable ultrafast emission in the vacuum ultraviolet using noble-gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Ermolov, Alexey; Frosz, Michael H; Travers, John C; Russell, Philip St J

    2015-01-01

    We report on the generation of a three-octave supercontinuum extending from the vacuum ultraviolet (VUV) to the near-infrared, spanning at least 113 to 1000 nm (i.e., 11 to 1.2 eV), in He-filled hollow-core kagome-style photonic crystal fiber. The same system also permits generation of narrower-band VUV radiation tunable from 113 to 200 nm with efficiencies exceeding 1% and VUV pulse energies in excess of 50 nJ. Modeling confirms that the mechanism involves soliton self-compression to sub-femtosecond pulse durations, dispersive-wave emission and the plasma-induced soliton self-frequency blue-shift. The bandwidth of the generated VUV light, which modeling shows to be coherent, is sufficient to support 500 as single-cycle pulses.

  13. Development of one-step hollow fiber supported liquid phase sampling technique for occupational workplace air analysis using high performance liquid chromatography with ultra-violet detector.

    Science.gov (United States)

    Yan, Cheing-Tong; Chien, Hai-Ying

    2012-07-13

    In this study, a simple and novel one-step hollow-fiber supported liquid-phase sampling (HF-LPS) technique was developed for enriched sampling of gaseous toxic species prior to chemical analysis for workplace air monitoring. A lab-made apparatus designed with a gaseous sample generator and a microdialysis sampling cavity (for HF-LPS) was utilized and evaluated to simulate gaseous contaminant air for occupational workplace analysis. Gaseous phenol was selected as the model toxic species. A polyethersulfone hollow fiber dialysis module filled with ethylene glycol in the shell-side was applied as the absorption solvent to collect phenol from a gas flow through the tube-side, based on the concentration distribution of phenol between the absorption solvent and the gas flow. After sampling, 20 μL of the extractant was analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Factors that influence the generation of gaseous standards and the HF-LPS were studied thoroughly. Results indicated that at 25 °C the phenol (2000 μg/mL) standard solution injected at 15-μL/min can be vaporized into sampling cavity under nitrogen flow at 780 mL/min, to generate gaseous phenol with concentration approximate to twice the permissible exposure limit. Sampling at 37.3 mL/min for 30 min can meet the requirement of the workplace air monitoring. The phenol in air ranged between 0.7 and 10 cm³/m³ (shows excellent linearity) with recovery between 98.1 and 104.1%. The proposed method was identified as a one-step sampling for workplace monitoring with advantages of convenience, rapidity, sensitivity, and usage of less-toxic solvent. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification.

    Science.gov (United States)

    Shin, Jung-Hun; Kim, Byung-Chun; Choi, Okkyoung; Kim, Hyunook; Sang, Byoung-In

    2015-10-01

    Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4(+)-N/m(3)/d and 0.10-0.21 kg NO3(-)-N/m(3)/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4(+) or NO3(-) loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs.

  15. Determination of melamine in soil samples using surfactant-enhanced hollow fiber liquid phase microextraction followed by HPLC–UV using experimental design

    Directory of Open Access Journals (Sweden)

    Ali Sarafraz Yazdi

    2015-11-01

    Full Text Available Surfactant-enhanced hollow fiber liquid phase (SE-HF-LPME microextraction was applied for the extraction of melamine in conjunction with high performance liquid chromatography with UV detection (HPLC–UV. Sodium dodecyl sulfate (SDS was added firstly to the sample solution at pH 1.9 to form hydrophobic ion-pair with protonated melamine. Then the protonated melamine–dodecyl sulfate ion-pair (Mel–DS was extracted from aqueous phase into organic phase immobilized in the pores and lumen of the hollow fiber. After extraction, the analyte-enriched 1-octanol was withdrawn into the syringe and injected into the HPLC. Preliminary, one variable at a time method was applied to select the type of extraction solvent. Then, in screening step, the other variables that may affect the extraction efficiency of the analyte were studied using a fractional factorial design. In the next step, a central composite design was applied for optimization of the significant factors having positive effects on extraction efficiency. The optimum operational conditions included: sample volume, 5 mL; surfactant concentration, 1.5 mM; pH 1.9; stirring rate, 1500 rpm and extraction time, 60 min. Using the optimum conditions, the method was analytically evaluated. The detection limit, relative standard deviation and linear range were 0.005 μg mL−1, 4.0% (3 μg mL−1, n = 5 and 0.01–8 μg mL−1, respectively. The performance of the procedure in extraction of melamine from the soil samples was good according to its relative recoveries in different spiking levels (95–109%.

  16. Compartmental Hollow Fiber Capillary Membrane–Based Bioreactor Technology for In Vitro Studies on Red Blood Cell Lineage Direction of Hematopoietic Stem Cells

    Science.gov (United States)

    Housler, Greggory J.; Miki, Toshio; Schmelzer, Eva; Pekor, Christopher; Zhang, Xiaokui; Kang, Lin; Voskinarian-Berse, Vanessa; Abbot, Stewart; Zeilinger, Katrin

    2012-01-01

    Continuous production of red blood cells (RBCs) in an automated closed culture system using hematopoietic stem cell (HSC) progenitor cell populations is of interest for clinical application because of the high demand for blood transfusions. Previously, we introduced a four-compartment bioreactor that consisted of two bundles of hollow fiber microfiltration membranes for transport of culture medium (forming two medium compartments), interwoven with one bundle of hollow fiber membranes for transport of oxygen (O2), carbon dioxide (CO2), and other gases (forming one gas compartment). Small-scale prototypes were developed of the three-dimensional (3D) perfusion cell culture systems, which enable convection-based mass transfer and integral oxygenation in the cell compartment. CD34+ HSC were isolated from human cord blood units using a magnetic separation procedure. Cells were inoculated into 2- or 8-mL scaled-down versions of the previously designed 800-mL cell compartment devices and perfused with erythrocyte proliferation and differentiation medium. First, using the small-scale 2-mL analytical scale bioreactor, with an initial seeding density of 800,000 cells/mL, we demonstrated approximately 100-fold cell expansion and differentiation after 7 days of culture. An 8-mL laboratory-scale bioreactor was then used to show pseudocontinuous production by intermediately harvesting cells. Subsequently, we were able to use a model to demonstrate semicontinuous production with up to 14,288-fold expansion using seeding densities of 800,000 cells/mL. The down-scaled culture technology allows for expansion of CD34+ cells and stimulating these progenitors towards RBC lineage, expressing approximately 40% CD235+ and enucleation. The 3D perfusion technology provides an innovative tool for studies on RBC production, which is scalable. PMID:21933020

  17. The Effects of Bore Fluid Composition and Coagulation Bath Temperature on the Structure and Performance of Polysulfone Hollow Fiber Membranes in Collagen Separation

    Directory of Open Access Journals (Sweden)

    Nasrin Attari

    2017-01-01

    Full Text Available The effects of N-methylpyrrolidone (NMP concentration contained in bore fluid and coagulation bath temperature were studied with respect to the structure as well as the performance of the polysulfone hollow fiber membranes. In order to determine the structural characteristics of prepared membranes, a set of analyses including scanning electron microscopy (SEM, mechanical strength test, pure water permeability and mean pore radius of surface pores were used and separation of 1 g/L solution of collagen protein was studied to determine the performance of the membranes. The obtained results from SEM analysis showed that at constant coagulation bath temperature, the increase in NMP concentration in bore fluid increased the number of pores in the inner surface of membranes, decreased the formation of finger-like voids and increased the mean pore radius of the pores and also sponge-like pores near the inner radius of hollow fiber membranes. Moreover, pure water permeability and mechanical strength of the prepared membranes increased about 160% and 44%, respectively with increases in the content of NMP in bore fluid. In addition, at constant NMP content of 40% in bore fluid, pure water permeability increased by above 92% as the coagulation bath temperature increased from 30°C to 50°C, whereas the mechanical strength decreased by 32%. Finally, it was revealed that the rejection of the prepared membranes in the separation of collagen protein solution decreased by increasing NMP content in the bore fluid at constant coagulation bath temperature and also deacreased by increasing coagulation bath temperature at constant NMP content in the bore fluid.

  18. Optimization of multiwalled carbon nanotubes reinforced hollow-fiber solid-liquid-phase microextraction for the determination of polycyclic aromatic hydrocarbons in environmental water samples using experimental design.

    Science.gov (United States)

    Hamedi, Raheleh; Hadjmohammadi, Mohammad Reza

    2017-09-01

    A novel design of hollow-fiber liquid-phase microextraction containing multiwalled carbon nanotubes as a solid sorbent, which is immobilized in the pore and lumen of hollow fiber by the sol-gel technique, was developed for the pre-concentration and determination of polycyclic aromatic hydrocarbons in environmental water samples. The proposed method utilized both solid- and liquid-phase microextraction media. Parameters that affect the extraction of polycyclic aromatic hydrocarbons were optimized in two successive steps as follows. Firstly, a methodology based on a quarter factorial design was used to choose the significant variables. Then, these significant factors were optimized utilizing central composite design. Under the optimized condition (extraction time = 25 min, amount of multiwalled carbon nanotubes = 78 mg, sample volume = 8 mL, and desorption time = 5 min), the calibration curves showed high linearity (R(2)  = 0.99) in the range of 0.01-500 ng/mL and the limits of detection were in the range of 0.007-1.47 ng/mL. The obtained extraction recoveries for 10 ng/mL of polycyclic aromatic hydrocarbons standard solution were in the range of 85-92%. Replicating the experiment under these conditions five times gave relative standard deviations lower than 6%. Finally, the method was successfully applied for pre-concentration and determination of polycyclic aromatic hydrocarbons in environmental water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Reduced graphene oxide-NH2 modified low pressure nanofiltration composite hollow fiber membranes with improved water flux and antifouling capabilities

    Science.gov (United States)

    Li, Xipeng; Zhao, Changwei; Yang, Mei; Yang, Bin; Hou, Deyin; Wang, Tao

    2017-10-01

    Reduced graphene oxide-NH2 (R-GO-NH2), a kind of amino graphene oxide, was embedded into the polyamide (PA) layer of nanofiltration (NF) composite hollow fiber membranes via interfacial polymerization to enhance the permeate flux and antifouling properties of NF membranes under low pressure conditions. In addition, it could mitigate the poor compatibility issue between graphene oxide materials and PA layer. To evaluate the influence of R-GO-NH2 on the performance of the NF composite hollow fiber membrane, SEM, AFM, FTIR, XPS and Zeta potentials were used to characterize the membranes. The results indicated that the compatibility and interactions between R-GO-NH2 and PA layer were enhanced, which was mainly due to the polymerization reaction between amino groups of R-GO-NH2 and acyl chloride groups of TMC. Therefore, salts rejection of the current membranes was improved significantly, and the modified membranes with 50 mg/L R-GO-NH2 demonstrated highest performance in terms of the rejections, which were 26.9%, 98.5%, 98.1%, and 96.1%, for NaCl, Na2SO4, MgSO4, and CaCl2 respectively. It was found that with the R-GO-NH2 contents rasing from 0 to 50 mg/L, pure water flux increased from 30.44 ± 1.71 to 38.57 ± 2.01 L/(m2.h) at 2 bar. What's more, the membrane demonstrated improved antifouling properties.

  20. Microwave photonics filtering interrogation technique under coherent regime for hot spot detection on cascaded FBG fiber

    Science.gov (United States)

    Hervás, Javier; Barrera, David; Madrigal, Javier; Sales, Salvador

    2017-04-01

    An interrogation technique of cascaded FBGs sensors based on a Microwave Photonics filtering technique under coherent regime is presented. The sensing information of a 5m fiber coil with 500 weak FBGs with a similar central wavelength is retrieved. The principle of operation is based on the calculation of the impulsive response by recording the electrical frequency response of the system. Hot spot detection and temperature measurement are demonstrated through experimental measurements with a temperature sensitivity of 0.6dB/ºC. The resolution in the measurement is related to the bandwidth of the electrical measurement and we have obtained a resolution of 20 cm for an electrical bandwidth of 1 GHz and a SNR bigger than 16dB.