Magnetoelectrolysis of Co nanowire arrays grown in a track-etched polycarbonate membrane

International Nuclear Information System (INIS)

Sanchez-Barriga, J.; Lucas, M.; Rivero, G.; Marin, P.; Hernando, A.

2007-01-01

Arrays of Cobalt nanowires with a controlled length of 6μm have been fabricated by electrochemical deposition into the pores of track-etched polycarbonate membranes with a nominal pore diameter of 30nm. The magnetic properties of Co-deposited nanowires and the effects of a magnetic field applied during electrodeposition of the arrays have been studied. An enhancement of the mass deposition rate due to the presence of a 50Oe magnetic field along the nanowire axis has been observed by measuring the experimental development of the current in the electrochemical cell during the fabrication process. X-ray diffraction measurements reveal a different polycrystalline degree for each deposition configuration, indicating that the crystalline structure of the deposited material has been substantially modified. Magnetic measurements show a clear dependence of the anisotropy directions on the orientation of the magnetic field applied during the electrodeposition

Deposition of Aerosol Particles in Electrically Charged Membrane Filters

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1972-05-15

A theory for the influence of electric charge on particle deposition on the surface of charged filters has been developed. It has been tested experimentally on ordinary membrane filters and Nuclepore filters of 8 mum pore size, with a bipolar monodisperse test aerosol of 1 mum particle diameter, and at a filter charge up to 20 muC/m2. Agreement with theory was obtained for the Coulomb force between filter and particle for both kinds of filters. The image force between charged filter and neutral particles did not result in the predicted deposition in the ordinary membrane filter, probably due to lacking correspondence between the filter model employed for the theory, and the real filter. For the Nuclepore filter a satisfactory agreement with theory was obtained, also at image interaction

Nanotechnology for membranes, filters and sieves

NARCIS (Netherlands)

Eijkel, Jan C.T.; van den Berg, Albert

2006-01-01

This mini-review is dedicated to the use of nanotechnology for membranes, filters and sieves. With the advent of nanotechnology researchers have acquired an unprecedented freedom to sculpt device geometry almost down to the molecular scale. Such structures can now replace the gels, membranes and

Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

Science.gov (United States)

Norby, Jessica; Strawn, Daniel; Brooks, Erin

2018-03-01

To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.45-μm pore size to distinguish between particulate and dissolved P species. However, filter membrane type is rarely specified in method protocols, and many different types of membranes are available. In this study, three common filter membrane materials (polyether sulfone, nylon, and nitrocellulose), all with 0.45-μm pore sizes, were tested for analytical differences in total P concentrations and dissolved reactive P (DRP) concentrations in water extracts from six soils sampled from two regions. Three of the extracts from the six soil samples had different total P concentrations for all three membrane types. The other three soil extracts had significantly different total P results from at least one filter membrane type. Total P concentration differences were as great as 35%. The DRP concentrations in the extracts were dependent on filter type in five of the six soil types. Results from this research show that filter membrane type is an important parameter that affects concentrations of total P and DRP from soil extracts. Thus, membrane type should be specified in soil extraction protocols. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Determination by Small-angle X-ray Scattering of Pore Size Distribution in Nanoporous Track-etched Polycarbonate Membranes

Science.gov (United States)

Jonas, A. M.; Legras, R.; Ferain, E.

1998-03-01

Nanoporous track-etched membranes with narrow pore size distributions and average pore size diameters tunable from 100 to 1000 Åare produced by the chemical etching of latent tracks in polymer films after irradiation by a beam of accelerated heavy ions. Nanoporous membranes are used for highly demanding filtration purposes, or as templates to obtain metallic or polymeric nanowires (L. Piraux et al., Nucl. Instr. Meth. Phys. Res. 1997, B131, 357). Such applications call for developments in nanopore size characterization techniques. In this respect, we report on the characterization by small-angle X-ray scattering (SAXS) of nanopore size distribution (nPSD) in polycarbonate track-etched membranes. The obtention of nPSD requires inverting an ill-conditioned inhomogeneous equation. We present different numerical routes to overcome the amplification of experimental errors in the resulting solutions, including a regularization technique allowing to obtain the nPSD without a priori knowledge of its shape. The effect of deviations from cylindrical pore shape on the resulting distributions are analyzed. Finally, SAXS results are compared to results obtained by electron microscopy and conductometry.

Improved permeation performance and fouling-resistance of Poly(vinyl chloride/Polycarbonate blend membrane with added Pluronic F127

Directory of Open Access Journals (Sweden)

Supateekan Pacharasakoolchai

2014-04-01

Full Text Available The aim of this work was to prepare and characterize poly(vinyl chloride (PVC/polycarbonate (PC blend membranes for use in ultrafiltration. Pluronic F127 was used as an additive to modify the membrane surface of the PVC/PC blended membranes. The PVC/PC blend membrane was first prepared using the phase inversion method from a casting solution of PVC with small amount of PC in N-methylpyrrolidone (NMP and water as the non-solvent. The morphologies structure and properties, such as tensile strength, water flux, and bovine serum albumin (BSA rejection of the blend membrane were studied. Increased amounts of PC resulted in an increase in the water flux and ability to reject protein. A concentration of 0.75 wt% PC provided the best improvement in tensile strength of blend membrane. Addition of different amounts of pluronic F127 to the casting solution of PVC/PC with a PC concentration of 0.75 wt% resulted in a decrease in the water contact angle that demonstrated the improvement of hydrophilicity of blend membrane. Scanning electron microscopy photographs showed that the modified PVC/PC membranes had a bigger pore volume in the porous sub-layer compared to the PVC/PC control membrane. The PVC/PC membrane with added Pluronic F127 exhibited a much higher flux and rejection of BSA in a protein filtration experiment than the PVC/PC membrane. An increase in flux recovery ratio of PVC/PC/pluronic 127 blend membrane indicated that the modified membranes could reduce membrane fouling useful for ultrafiltration.

Filterability and Sludge Concentration in Membrane Bioreactors

NARCIS (Netherlands)

Lousada-Ferreira, M.

2011-01-01

The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of

Response of MG63 osteoblast-like cells onto polycarbonate membrane surfaces with different micropore sizes.

Science.gov (United States)

Lee, Sang Jin; Choi, Jin San; Park, Ki Suk; Khang, Gilson; Lee, Young Moo; Lee, Hai Bang

2004-08-01

Response of different types of cells on materials is important for the applications of tissue engineering and regenerative medicine. It is recognized that the behavior of the cell adhesion, proliferation, and differentiation on materials depends largely on surface characteristics such as wettability, chemistry, charge, rigidity, and roughness. In this study, we examined the behavior of MG63 osteoblast-like cells cultured on a polycarbonate (PC) membrane surfaces with different micropore sizes (0.2-8.0 microm in diameter). Cell adhesion and proliferation to the PC membrane surfaces were determined by cell counting and MTT assay. The effect of surface micropore on the MG63 cells was evaluated by cell morphology, protein content, and alkaline phosphatase (ALP) specific activity. It seems that the cell adhesion and proliferation were progressively inhibited as the PC membranes had micropores with increasing size, probably due to surface discontinuities produced by track-etched pores. Increasing micropore size of the PC membrane results in improved protein synthesis and ALP specific activity in isolated cells. There was a statistically significant difference (Pmicropore sizes. The MG63 cells also maintained their phenotype under conditions that support a round cell shape. RT-PCR analysis further confirmed the osteogenic phenotype of the MG63 cells onto the PC membranes with different micropore sizes. In results, as micropore size is getting larger, cell number is reduced and cell differentiation and matrix production is increased. This study demonstrated that the surface topography plays an important role for phenotypic expression of the MG63 osteoblast-like cells.

Prepare and characterization of nanocomposite - mixed matrix membranes based on polycarbonate; Preparo e caracterizacao de membranas polimericas de matriz mista nanocomposito baseadas em policarbonato

Energy Technology Data Exchange (ETDEWEB)

Paranhos, Caio M; Pessan, Luiz A., E-mail: caiomp.dema@gmail.co [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais. Lab. de Permeacao e Sorcao; Gomes, Ana C. de O. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas

2009-07-01

Mixed matrix membranes based on polycarbonate with different content of sepiolite were prepared by casting. The obtained membranes were characterized by wide-angle X-ray diffraction, thermal analysis, optical transparency and permeation to oxygen. The presence of sepiolite leads to the formation of a polymer-clay interface. The presence of the interface causes the increase in O{sub 2} permeation. Increasing content of sepiolite results in aggregates of sepiolite, which forms preferential channels to the O{sub 2} molecules. This fact is directly related to the strong increasing observed in O{sub 2} permeability. (author)

Taheri-Saramad x-ray detector (TSXD): a novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane.

Science.gov (United States)

Taheri, A; Saramad, S; Ghalenoei, S; Setayeshi, S

2014-01-01

A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 μm, respectively.

Taheri-Saramad x-ray detector (TSXD): A novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane

Energy Technology Data Exchange (ETDEWEB)

Taheri, A., E-mail: at1361@aut.ac.ir; Saramad, S.; Ghalenoei, S.; Setayeshi, S. [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 15875-4413 (Iran, Islamic Republic of)

2014-01-15

A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 μm, respectively.

Degradation and stability of polycarbonate sterilized by gamma rays

International Nuclear Information System (INIS)

Araujo, E.S.; Guedes, S.M.L.

1995-01-01

The purpose of this paper is to study the behavior of the polycarbonate (poly (bis phenol-A carbonate)) when it is sterilized by gamma rays because undesirable discoloration appears. Aromatic polycarbonates are amorphous polymers usually prepared from bis phenols and phosgene by interfacial polymerization. They are employed in medical applications, including blood filters, dialyzers, oxygenators and sterilizing equipment. At present, the best process for sterilization of medical supplies is present, the best process for sterilization of medical supplies is gamma irradiation. The two major effects of γ-radiation in polymers are crosslinking and main chain scission. Both effects coexist and either one may predominate depending on the chemical structure of the polymer and the conditions of irradiation. (author). 5 refs, 6 figs, 1 tab

Development of membrane filters with nanostructured porous layer by coating of metal nanoparticles sintered onto a micro-filter

International Nuclear Information System (INIS)

Park, Seok Joo; Park, Young Ok; Lee, Dong Geun; Ryu, Jeong In

2008-01-01

The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 KPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%

Controlled nanostructure and high loading of single-walled carbon nanotubes reinforced polycarbonate composite

International Nuclear Information System (INIS)

Wang Shiren; Liang Zhiyong; Pham, Giang; Park, Young-Bin; Wang, Ben; Zhang, Chuck; Kramer, Leslie; Funchess, Percy

2007-01-01

This paper presents an effective technique to fabricate thermoplastic nanocomposites with high loading of well-dispersed single-walled carbon nanotubes (SWNTs). SWNT membranes were made from a multi-step dispersion and filtration method, and then impregnated with polycarbonate solution to make thermoplastic nanocomposites. High loading of nanotubes was achieved by controlling the viscosity of polycarbonate solution. SEM and AFM characterization results revealed the controlled nanostructure in the resultant nanocomposites. Dynamic mechanical property tests indicated that the storage modulus of the resulting nanocomposites at 20 wt% nanotubes loading was improved by a factor of 3.4 compared with neat polycarbonate material. These results suggest the developed approach is an effective way to fabricate thermoplastic nanocomposites with good dispersion and high SWNT loading

Assessment of a membrane drinking water filter in an emergency setting.

Science.gov (United States)

Ensink, Jeroen H J; Bastable, Andy; Cairncross, Sandy

2015-06-01

The performance and acceptability of the Nerox(TM) membrane drinking water filter were evaluated among an internally displaced population in Pakistan. The membrane filter and a control ceramic candle filter were distributed to over 3,000 households. Following a 6-month period, 230 households were visited and filter performance and use were assessed. Only 6% of the visited households still had a functioning filter, and the removal performance ranged from 80 to 93%. High turbidity in source water (irrigation canals), together with high temperatures and large family size were likely to have contributed to poor performance and uptake of the filters.

Polycarbonate-based ordered arrays of electrochemical nanoelectrodes obtained by e-beam lithography

Energy Technology Data Exchange (ETDEWEB)

Moretto, L M; De Leo, M; Ugo, P [Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, Santa Marta 2137, 30123 Venice (Italy); Tormen, M; Carpentiero, A, E-mail: ugo@unive.it [CNR-IOM, TASC Laboratory, Basovizza S S 14 km 163.5, 34149 Trieste (Italy)

2011-05-06

Ordered arrays of nanoelectrodes for electrochemical use are prepared by electron beam lithography (EBL) using polycarbonate as a novel e-beam resist. The nanoelectrodes are fabricated by patterning arrays of holes in a thin film of polycarbonate spin-coated on a gold layer on Si/Si{sub 3}N{sub 4} substrate. Experimental parameters for the successful use of polycarbonate as high resolution EBL resist are optimized. The holes can be filled partially or completely by electrochemical deposition of gold. This enables the preparation of arrays of nanoelectrodes with different recession degree and geometrical characteristics. The polycarbonate is kept on-site and used as the insulator that separates the nanoelectrodes. The obtained nanoelectrode arrays (NEAs) exhibit steady state current controlled by pure radial diffusion in cyclic voltammetry for scan rates up to approximately 50 mV s{sup -1}. Electrochemical results showed satisfactory agreement between experimental voltammograms and suitable theoretical models. Finally, the peculiarities of NEAs versus ensembles of nanoelectrodes, obtained by membrane template synthesis, are critically evaluated.

Photostable nonlinear optical polycarbonates

NARCIS (Netherlands)

Faccini, M.; Balakrishnan, M.; Diemeer, Mart; Torosantucci, Riccardo; Driessen, A.; Reinhoudt, David; Verboom, Willem

2008-01-01

Highly thermal and photostable nonlinear optical polymers were obtained by covalently incorporating the tricyanovinylidenediphenylaminobenzene (TCVDPA) chromophore to a polycarbonate backbone. NLO polycarbonates with different chromophore attachment modes and flexibilities were synthesized. In spite

Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

International Nuclear Information System (INIS)

Kausar, A.

2016-01-01

Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

Evaluation of the release behavior of the dexamethasone embedded in polycarbonate polyurethane membranes: an in vitro study

International Nuclear Information System (INIS)

Kim, Dong Hyun; Kang, Sung Gwon; Lee, Chul Gab; Park, Sang Soo; Lee, Don Haeng; Lee, Gyu Baek; Song, Ho Young

2003-01-01

To evaluate the release behavior of dexamethasone embedded in a polycarbonate polyurethane membrane. Both water-soluble and water-insoluble dexamethasone were tested, and the release behavior of five water-insoluble dexamethasone films of different thickness (78 to 211 μm) was also evaluated. The amount of dexamethasone used was 10% of the total weight of the polyurethan film mass. Each film was placed in a centrifuge tube containing 25 ml of 0.1-M neutral phosphate buffer, and the tubes were placed in a shaking incubator to quantify the amount of drug released into the buffer, absorption spectroscopy (λ max=242 nm) was employed. In the test involving water-soluble dexamethasone, 60%, of the drug was released during the first two hours of the study. Films containing water-insoluble dexamethasone, on the other hand, released 40%, 60% and 75% of the dexamethasone in one, three and seven days, respectively. Both types of film maintained low-dose drug release for 28 days. When release behavior was compared between water-insoluble films of different thickness, thicker film showed less initial burst and more sustained release. Dexamethasone release behavior varies according to drug solubility and membrane thickness, and may thus be conrolled

Influence of membrane fouling reducers (MFRs) on filterability of disperse mixed liquor of jet loop bioreactors.

Science.gov (United States)

Koseoglu-Imer, Derya Yuksel; Dizge, Nadir; Karagunduz, Ahmet; Keskinler, Bulent

2011-07-01

The effects of membrane fouling reducers (MFRs) (the cationic polyelectrolyte (CPE) and FeCI(3)) on membrane fouling were studied in a lab-scale jet loop submerged membrane bioreactor (JL-SMBR) system. The optimum dosages of MFRs (CPE dosage=20 mg g(-1)MLSS, FeCI(3) dosage=14 mg g(-1)MLSS) were continuously fed to JL-SMBR system. The soluble and bound EPS concentrations as well as MLSS concentration in the mixed liquor of JL-SMBR were not changed substantially by the addition of MFRs. However, significant differences were observed in particle size and relative hydrophobicity. Filtration tests were performed by using different membrane types (polycarbonate (PC) and nitrocellulose mixed ester (ME)) and various pore sizes (0.45-0.22-0.1 μm). The steady state fluxes (J(ss)) of membranes increased at all membranes after MFRs addition to JL-SMBR. The filtration results showed that MFRs addition was an effective approach in terms of improvement in filtration performance for both membrane types. Copyright © 2011 Elsevier Ltd. All rights reserved.

Combined FDTD-Monte Carlo analysis and a novel design for ZnO scintillator rods in polycarbonate membrane for X-ray imaging

International Nuclear Information System (INIS)

Mohammadian-Behbahani, Mohammad-Reza; Saramad, Shahyar; Mohammadi, Mohammad

2017-01-01

A combination of Finite Difference Time Domain (FDTD) and Monte Carlo (MC) methods is proposed for simulation and analysis of ZnO microscintillators grown in polycarbonate membrane. A planar 10 keV X-ray source irradiating the detector is simulated by MC method, which provides the amount of absorbed X-ray energy in the assembly. The transport of generated UV scintillation light and its propagation in the detector was studied by the FDTD method. Detector responses to different probable scintillation sites and under different energies of X-ray source from 10 to 25 keV are reported. Finally, the tapered geometry for the scintillators is proposed, which shows enhanced spatial resolution in comparison to cylindrical geometry for imaging applications.

Combined FDTD-Monte Carlo analysis and a novel design for ZnO scintillator rods in polycarbonate membrane for X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Mohammadian-Behbahani, Mohammad-Reza [Department of Energy Engineering and Physics, Amir-Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); Saramad, Shahyar, E-mail: ssaramad@aut.ac.ir [Department of Energy Engineering and Physics, Amir-Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); Mohammadi, Mohammad [Department of Electrical Engineering, Amir-Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of)

2017-05-01

A combination of Finite Difference Time Domain (FDTD) and Monte Carlo (MC) methods is proposed for simulation and analysis of ZnO microscintillators grown in polycarbonate membrane. A planar 10 keV X-ray source irradiating the detector is simulated by MC method, which provides the amount of absorbed X-ray energy in the assembly. The transport of generated UV scintillation light and its propagation in the detector was studied by the FDTD method. Detector responses to different probable scintillation sites and under different energies of X-ray source from 10 to 25 keV are reported. Finally, the tapered geometry for the scintillators is proposed, which shows enhanced spatial resolution in comparison to cylindrical geometry for imaging applications.

Identification of DNA viruses by membrane filter hybridization.

OpenAIRE

Stålhandske, P; Pettersson, U

1982-01-01

The use of membrane filter hybridization for the identification of DNA viruses is described. We designed and used a procedure for identification of herpes simplex virus. This method can discriminate between herpes simplex virus types 1 and 2 in a simple way.

Effects of closed immersion filtered water flow velocity on the ablation threshold of bisphenol A polycarbonate during excimer laser machining

International Nuclear Information System (INIS)

Dowding, Colin; Lawrence, Jonathan

2010-01-01

A closed flowing thick film filtered water immersion technique ensures a controlled geometry for both the optical interfaces of the flowing liquid film and allows repeatable control of flow-rate during machining. This has the action of preventing splashing, ensures repeatable machining conditions and allows control of liquid flow velocity. To investigate the impact of this technique on ablation threshold, bisphenol A polycarbonate samples have been machined using KrF excimer laser radiation passing through a medium of filtered water flowing at a number of flow velocities, that are controllable by modifying the liquid flow-rates. An average decrease in ablation threshold of 7.5% when using turbulent flow velocity regime closed thick film filtered water immersed ablation, compared to ablation using a similar beam in ambient air; however, the use of laminar flow velocities resulted in negligible differences between closed flowing thick film filtered water immersion and ambient air. Plotting the recorded threshold fluence achieved with varying flow velocity showed that an optimum flow velocity of 3.00 m/s existed which yielded a minimum ablation threshold of 112 mJ/cm 2 . This is attributed to the distortion of the ablation plume effected by the flowing immersion fluid changing the ablation mechanism: at laminar flow velocities Bremsstrahlung attenuation decreases etch rate, at excessive flow velocities the plume is completely destroyed, removing the effect of plume etching. Laminar flow velocity regime ablation is limited by slow removal of debris causing a non-linear etch rate over 'n' pulses which is a result of debris produced by one pulse remaining suspended over the feature for the next pulse. The impact of closed thick film filtered water immersed ablation is dependant upon beam fluence: high fluence beams achieved greater etch efficiency at high flow velocities as the effect of Bremsstrahlung attenuation is removed by the action of the fluid on the plume; low

Transfer in SDS of biotinylated proteins from acrylamide gels to an avidin-coated membrane filter.

Science.gov (United States)

Karlin, Arthur; Wang, Chaojian; Li, Jing; Xu, Qiang

2004-06-01

Avidin was covalently linked to aldehyde-derivatized polyethersulfone membrane filters. These filters were used in Western blot analysis of proteins reacted with biotinylation reagents and electrophoresed in sodium dodecyl sulfate (SDS) on polyacrylamide gels. Electrophoretic transfer from the gels to these filters was in 0.1% SDS, in which the covalently bound avidin retained its biotin-binding capacity. We compared Western blots on avidin-coated membrane filters of biotinylated and nonbiotinylated forms of mouse immunoglobulin G (IgG), mouse IgG heavy chain, muscle-type acetylcholine receptor alpha subunit, and fused alpha and beta subunits of receptor. Biotinylated proteins were captured with high specificity compared to their nonbiotinylated counterparts and sensitively detected on the avidin-coated membranes.

Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

Directory of Open Access Journals (Sweden)

Bruderek Juliane

2008-10-01

Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

Evaluation of frictional forces of polycarbonate self-ligating brackets.

Science.gov (United States)

Fernandes, Daniel J; Miguel, José Augusto M; Quintão, Catia C A; Elias, Carlos N

2010-01-01

To evaluate the frictional forces generated by ceramic- (Opal, Ultradent) and glass-fiber-reinforced polycarbonate self-ligating brackets (Oyster, Gestenco) and compare the effectiveness of these ligatureless systems with glass-fiber-reinforced polycarbonate conventional brackets (Blonde, Gestenco). The hypothesis is that there is no difference between frictional forces generated by ceramic- and glass-fiber-reinforced polycarbonate self-ligating and glass-fiber-reinforced polycarbonate conventional brackets. Twelve preadjusted 0.022 3 0.028-inch maxillary canine brackets were tested, divided into three groups: Opal, Oyster, and Blonde. Frictional tests were conducted with the Emic DL 10000 testing machine with a 20 N loadcell for 40 seconds at a 0.5 cm/min speed. Each bracket-wire combination was tested five times. The data generated were analyzed by parametric analysis of variance (one-way ANOVA) and Bonferroni tests. Analysis of variance indicated significant differences for the three groups (Pfrictional forces of the Oyster glass-fiber-reinforced polycarbonate self-ligating brackets were significantly lower (37.0 ± 8.9 cN) than those of the Opal ceramic-reinforced polycarbonate self-ligating brackets (49.5 ± 10.1 cN), while the Blonde glass-fiber-reinforced conventional bracket frictional forces were 105.8 ± 6.4 cN. Oyster glass-fiber-reinforced polycarbonate brackets produced less friction than Opal ceramic-reinforced polycarbonate brackets. The polycarbonate ligatureless system showed significantly lower frictional forces compared to Blonde conventional polycarbonate brackets tied with elastomeric ligatures. The study rejected the initial hypothesis because there are significant differences of frictional forces among the tested systems. © 2010 BY QUINTESSENCE PUBLISHING CO, INC.

Direct quantification of airborne nanoparticles composition by TXRF after collection on filters

Energy Technology Data Exchange (ETDEWEB)

Motellier, S; Lhaute, K; Guiot, A; Golanski, L; Tardif, F [CEA Grenoble, DRT, LITEN, DTNM, Laboratory of Nanochemistry and Nanosafety, 17 Avenue des Martyrs, Cedex 9, F-38054 Grenoble (France); Geoffroy, C, E-mail: sylvie.motellier@cea.fr [Elexience, 9 rue des petits ruisseaux, BP 61, 91371 Verrieres-le-Buisson Cedex (France)

2011-07-06

Direct TXRF analysis of nanoparticles deposited on filters was evaluated. Standard filters spiked with known amounts of NP were produced using an atomizer which generates an aerosol from a NP containing-liquid suspension. Polycarbonate filters provided the highest fluorescence signals and black polycarbonate filters containing chromium were further selected, Cr being used as internal standard for elemental quantification of the filter contaminants. Calibration curves were established for various NP (TiO{sub 2}, ZnO, CeO{sub 2}, Al{sub 2}O{sub 3}). Good linearity was observed. Low limits of detection were in the tens to the hundreds of ngs per filter, the method being less adapted to Al{sub 2}O{sub 3} due to the poor TXRF sensitivity for light elements. The analysis of MW-CNTs was attempted by quantification of their metal (Fe) catalyst impurities. Problems like CNT dispersion in liquids, quantification of the deposited quantity and high Fe-background contamination.

Activated sludge filterability and full-scale membrane bioreactor operation

NARCIS (Netherlands)

Krzeminski, P.

2013-01-01

Despite continuous developments in the field of MBR technology, membrane fouling together with the associated energy demand and related costs issues remain major challenges. The efficiency of the filtration process in an MBR is governed by the activated sludge filterability, which is still limitedly

Applying graphene oxide nano-film over a polycarbonate nanoporous membrane to monitor E. coli by infrared spectroscopy.

Science.gov (United States)

Singh, Krishna Pal; Dhek, Neeraj Singh; Nehra, Anuj; Ahlawat, Sweeti; Puri, Anu

2017-01-05

Nano-biosensors are excellent monitoring tools for rapid, specific, sensitive, inexpensive, in-field, on-line, and/or real-time detection of pathogens in foods, soil, air, and water samples. A variety of nano-materials (metallic, polymeric, and/or carbon-based) were employed to enhance the efficacy, efficiency, and sensitivity of these nano-biosensors, including graphene-based materials, especially graphene oxide (GO)-based materials. GO bears many oxygen-bearing groups, enabling ligand conjugation at the high density critical for sensitive detection. We have fabricated GO-modified nano-porous polycarbonate track-etched (PCTE) membranes that were conjugated to an Escherichia coli-specific antibody (Ab) and used to detect E. coli. The random distribution of nanopores on the PCTE membrane surface and the bright coating of the GO onto the membrane were confirmed by scanning electron microscope. Anti-E. coli β-gal Abs were conjugated to the GO surface via 1-ethyl-3,3-dimethylaminopropyl carbodiimide hydrochloride-N-hydroxysuccinimide chemistry; antibody coating was confirmed by the presence of a characteristic IR peak near 1600cm(-1). A non-corresponding Ab (anti-Pseudomonas) was used as a negative control under identical conditions. When E. coli interacted anti-E.coli β-gal with Ab-coated GO-nano-biosensor units, we observed a clear shift in the IR peak from 3373.14 to 3315cm(-1); in contrast, we did not observe any shift in IR peaks when the GO unit was coated with the non-corresponding Ab (anti-Pseudomonas). Therefore, the detection of E. coli using the described GO-nano-sensor unit is highly specific, is highly selective and can be applied for real-time monitoring of E. coli with a detection limit between 100μg/mL and 10μg/mL, similar to existing detection systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparing Nutrient Removal from Membrane Filtered and Unfiltered Domestic Wastewater Using Chlorella vulgaris

Science.gov (United States)

Mayhead, Elyssia; Llewellyn, Carole A.; Fuentes-Grünewald, Claudio

2018-01-01

The nutrient removal efficiency of Chlorella vulgaris cultivated in domestic wastewater was investigated, along with the potential to use membrane filtration as a pre-treatment tool during the wastewater treatment process. Chlorella vulgaris was batch cultivated for 12 days in a bubble column system with two different wastewater treatments. Maximum uptake of 94.18% ammonium (NH4-N) and 97.69% ortho-phosphate (PO4-P) occurred in 0.2 μm membrane filtered primary wastewater. Membrane filtration enhanced the nutrient uptake performance of C. vulgaris by removing bacteria, protozoa, colloidal particles and suspended solids, thereby improving light availability for photosynthesis. The results of this study suggest that growing C. vulgaris in nutrient rich membrane filtered wastewater provides an option for domestic wastewater treatment to improve the quality of the final effluent. PMID:29351200

Binding of (/sup 3/H)imipramine to human platelet membranes with compensation for saturable binding to filters and its implication for binding studies with brain membranes

Energy Technology Data Exchange (ETDEWEB)

Phillips, O.M.; Wood, K.M.; Williams, D.C.

1984-08-01

Apparent specific binding of (/sup 3/H)imipramine to human platelet membranes at high concentrations of imipramine showed deviation from that expected of a single binding site, a result consistent with a low-affinity binding site. The deviation was due to displaceable, saturable binding to the glass fibre filters used in the assays. Imipramine, chloripramine, desipramine, and fluoxetine inhibited binding to filters whereas 5-hydroxytryptamine and ethanol were ineffective. Experimental conditions were developed that eliminated filter binding, allowing assay of high- and low-affinity binding to membranes. Failure to correct for filter binding may lead to overestimation of binding parameters, Bmax and KD for high-affinity binding to membranes, and may also be misinterpreted as indicating a low-affinity binding component in both platelet and brain membranes. Low-affinity binding (KD less than 2 microM) of imipramine to human platelet membranes was demonstrated and its significance discussed.

Photodegradation and stability of bisphenol a polycarbonate in weathering conditions

NARCIS (Netherlands)

Diepens, M.

2009-01-01

Polycarbonates, and especially bisphenol A polycarbonate (BPA-PC), are used in many fields of applications due to their excellent physical and mechanical properties, such as high impact resistance, ductility, and transparency. One major drawback of using polycarbonates in outdoor applications is

Computational and experimental study of nanoporous membranes for water desalination and decontamination.

Energy Technology Data Exchange (ETDEWEB)

Hickner, Michael A. (Penn State University, University Park, PA); Chinn, Douglas Alan (Sandia National Laboratories, Albuquerque, NM); Adalsteinsson, Helgi; Long, Kevin R. (Texas Tech University, Lubbock, TX); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM); Debusschere, Bert J.; Zendejas, Frank J.; Tran, Huu M.; Najm, Habib N.; Simmons, Blake Alexander

2008-11-01

Fundamentals of ion transport in nanopores were studied through a joint experimental and computational effort. The study evaluated both nanoporous polymer membranes and track-etched nanoporous polycarbonate membranes. The track-etched membranes provide a geometrically well characterized platform, while the polymer membranes are more closely related to ion exchange systems currently deployed in RO and ED applications. The experimental effort explored transport properties of the different membrane materials. Poly(aniline) membranes showed that flux could be controlled by templating with molecules of defined size. Track-etched polycarbonate membranes were modified using oxygen plasma treatments, UV-ozone exposure, and UV-ozone with thermal grafting, providing an avenue to functionalized membranes, increased wettability, and improved surface characteristic lifetimes. The modeling effort resulted in a novel multiphysics multiscale simulation model for field-driven transport in nanopores. This model was applied to a parametric study of the effects of pore charge and field strength on ion transport and charge exclusion in a nanopore representative of a track-etched polycarbonate membrane. The goal of this research was to uncover the factors that control the flux of ions through a nanoporous material and to develop tools and capabilities for further studies. Continuation studies will build toward more specific applications, such as polymers with attached sulfonate groups, and complex modeling methods and geometries.

Micron-pore-sized metallic filter tube membranes for filtration of particulates and water purification.

Science.gov (United States)

Phelps, T J; Palumbo, A V; Bischoff, B L; Miller, C J; Fagan, L A; McNeilly, M S; Judkins, R R

2008-07-01

Robust filtering techniques capable of efficiently removing particulates and biological agents from water or air suffer from plugging, poor rejuvenation, low permeance, and high backpressure. Operational characteristics of pressure-driven separations are in part controlled by the membrane pore size, charge of particulates, transmembrane pressure and the requirement for sufficient water flux to overcome fouling. With long term use filters decline in permeance due to filter-cake plugging of pores, fouling, or filter deterioration. Though metallic filter tube development at ORNL has focused almost exclusively on gas separations, a small study examined the applicability of these membranes for tangential filtering of aqueous suspensions of bacterial-sized particles. A mixture of fluorescent polystyrene microspheres ranging in size from 0.5 to 6 microm in diameter simulated microorganisms in filtration studies. Compared to a commercial filter, the ORNL 0.6 microm filter averaged approximately 10-fold greater filtration efficiency of the small particles, several-fold greater permeance after considerable use and it returned to approximately 85% of the initial flow upon backflushing versus 30% for the commercial filter. After filtering several liters of the particle-containing suspension, the ORNL composite filter still exhibited greater than 50% of its initial permeance while the commercial filter had decreased to less than 20%. When considering a greater filtration efficiency, greater permeance per unit mass, greater percentage of rejuvenation upon backflushing (up to 3-fold), and likely greater performance with extended use, the ORNL 0.6 microm filters can potentially outperform the commercial filter by factors of 100-1,000 fold.

Reactive electrospinning and biodegradation of cross-linked methacrylated polycarbonate nanofibers

Energy Technology Data Exchange (ETDEWEB)

Wu Ruizhi; Zhang Jianfeng; Fan Yuwei; Xu Xiaoming [Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States); Stoute, Diana; Lallier, Thomas, E-mail: xxu@lsuhsc.edu [Department of Cell Biology and Anatomy, Louisiana State University Health Science Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States)

2011-06-15

The objectives of this study were to fabricate cross-linked biodegradable polycarbonate nanofibers and to investigate their biodegradability by different enzymes. Poly(2,3-dihydroxycarbonate) was synthesized from naturally occurring l-tartaric acid. The hydroxyl groups on the functional polycarbonate were converted to methacrylate groups to enable the polymer to cross-link under UV irradiation. Smooth cross-linked methacrylated polycarbonate nanofibers (300-1800 nm) were fabricated by a reactive electrospinning process with in situ UV radiation from a mixed solution of linear methacrylated polycarbonate (MPC) and poly(ethylene oxide) (PEO) (MPC:PEO = 9:1) in methanol/chloroform (50/50). These cross-linked nanofibers have shown excellent solvent resistance and their solubility decreases with increasing degree of cross-linking. The thermal properties of linear and cross-linked polycarbonate nanofibers were investigated by differential scanning calorimetry and thermogravimetric analysis. The cross-linked polycarbonate nanofibers show no melting point below 200 {sup 0}C and their decomposition temperature increases with increasing cross-linking degree. Their biodegradation products by five different enzymes were analyzed using liquid chromatography-mass spectrometry (LC-MS). The biodegradability of the polycarbonate nanofibers decreases with increasing cross-linking degree. These nanofibers were found to support human fibroblast survival and to promote cell attachment. This study demonstrates that cross-linked biodegradable polycarbonate nanofibers with different chemical properties and biodegradability can be fabricated using the novel reactive electrospinning technology to meet the needs of different biomedical applications.

THE AQUATIC-POLYCARBONATE SKYLIGHT FOR SURABAYA INDONESIA

Directory of Open Access Journals (Sweden)

Danny Santoso Mintorogo

2007-01-01

Full Text Available This paper will indicate of how appropriate use of aquatic skylight module installed on buildings in the tropical zone compared to the ones in the subtropical climate. In order for energy saving strategies, the aquatic-polycarbonate skylight system is used in the tropical climate. In the tropical hot humid climate, Indonesia has received huge amount of global direct and diffuse radiations on horizontal roofs throughout the year, approximately 525 watts per square meter of solar radiation will impact on flat roofs or skylights on a clear sunny day in Surabaya city. Ironically, most of the commercial and institution buildings are equipped with Western skylight styles in Surabaya without any modifications. The aquatic-polycarbonate skylight is the system that will control daylight, scatter direct solar heat radiation, cool the indoor polycarbonate surface temperature, and collect solar hot water at the same time. The concept of using the water as shading device has three goals: first of all, the flushing water in the polycarbonate holes tries to scatter horizontal or tiled skylight direct sun-ray radiation, and minimize the direct sun heat temperature on the polycarbonate with flushing water continuously. Secondly, the sparkle flushing water in series of square holes of polycarbonate will bounce and disperse the direct sunlight into the space below enhancing daylight patterns. Finally, while bouncing, sparkling and scattering direct sunlight, those series of flushing water holes would also collect the solar heat radiation as solar hot water. Each system could works nicely to absorb, to scatter, to minimize, and to obtain the solar heat radiation for solar hot water in buildings. This strategy aims to provide a clean environment living zones with applying passive heating and cooling systems.

Examination of quantitative accuracy of PIXE analysis for atmospheric aerosol particle samples. PIXE analysis of NIST air particulate on filter media

International Nuclear Information System (INIS)

Saitoh, Katsumi; Sera, Koichiro

2005-01-01

In order to confirm accuracy of the direct analysis of filter samples containing atmospheric aerosol particles collected on a polycarbonate membrane filter by PIXE, we carried out PIXE analysis on a National Institute of Standards and Technology (NIST, USA) air particulate on filter media (SRM 2783). For 16 elements with NIST certified values determined by PIXE analysis - Na, Mg, Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb - quantitative values were 80-110% relative to NIST certified values except for Na, Al, Si and Ni. Quantitative values of Na, Al and Si were 140-170% relative to NIST certified values, which were all high, and Ni was 64%. One possible reason why the quantitative values of Na, Al and Si were higher than the NIST certified values could be the difference in the X-ray spectrum analysis method used. (author)

Facile attachment of nonlinear optical chromophores to polycarbonates

NARCIS (Netherlands)

Faccini, M.; Balakrishnan, M.; Torosantucci, Riccardo; Driessen, A.; Reinhoudt, David; Verboom, Willem

2008-01-01

A versatile, generally applicable synthetic methodology for side-chain NLO polycarbonates was developed. This represents the first example of covalent incorporation of NLO chromophores to a prepolymerized polycarbonate backbone. This methodology allows to adjust the polymer backbone structure and to

Correlation of antispermatozoal antibody with infertility in immunized female rabbits using 14C-protein A in a filter radioassay

International Nuclear Information System (INIS)

Eng, L.A.; Metz, C.B.

1986-01-01

The meaningful detection of antisperm antibody in immunologically infertile females has been confounded by the many methods of assay that exist. With many of these methods there is poor correlation of assay results with infertility. In this report, female rabbits were rendered partially or completely infertile by immunization with sperm fractions. A filter radioassay for antisperm antibody was developed that consists of incubating 10(7) sperm with sperm from immunized rabbits and 14 C-Protein A, a long-lived and versatile indirect radiolabel for many antibodies of the IgG class. The spermatozoa are washed by rapid vacuum filtration on polycarbonate membrane filters instead of by time-consuming centrifugation. The filters with the collected spermatozoa are then counted in a liquid scintillation counter. Sera from female rabbits isoimmunized with sperm antigens show a highly significant correlation (r = -0.904; p less than 0.001) between assay results and infertility as measured by the percentage of eggs that underwent cleavage after artificial insemination

PIXE analysis of atmospheric particulate matter in glas fibre filters

International Nuclear Information System (INIS)

Tabacniks, M.H.; Orsini, C.Q.; Maenhaut, W.

1993-01-01

A 3-step extraction procedure was developed to allow particle-induced X-ray emission (PIXE) analysis of particulate matter in normal glass fibre filter samples. The detection limits, expressed in ng/m 3 of air, for the filter extracts were 5 to 30 times lower than those achieved by PIXE analysis or ordinary Nuclepore polycarbonate filter samples. The concentration results were compared with those obtained from routine atomic absorption spectrometry measurements and with the PIXE data from Nuclepore stacked filter unit samples taken in parallel. (orig.)

21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

Science.gov (United States)

2010-04-01

... polycarbonate film. 175.365 Section 175.365 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... chloride copolymer coatings for polycarbonate film. Vinylidene chloride copolymer coatings identified in this section and applied on polycarbonate film may be safely used as food-contact surfaces, in...

Three-Dimensional Printing of Bisphenol A-Free Polycarbonates.

Science.gov (United States)

Zhu, Wei; Pyo, Sang-Hyun; Wang, Pengrui; You, Shangting; Yu, Claire; Alido, Jeffrey; Liu, Justin; Leong, Yew; Chen, Shaochen

2018-02-14

Polycarbonates are widely used in food packages, drink bottles, and various healthcare products such as dental sealants and tooth coatings. However, bisphenol A (BPA) and phosgene used in the production of commercial polycarbonates pose major concerns to public health safety. Here, we report a green pathway to prepare BPA-free polycarbonates (BFPs) by thermal ring-opening polymerization and photopolymerization. Polycarbonates prepared from two cyclic carbonates in different mole ratios demonstrated tunable mechanical stiffness, excellent thermal stability, and high optical transparency. Three-dimensional (3D) printing of the new BFPs was demonstrated using a two-photon laser direct writing system and a rapid 3D optical projection printer to produce structures possessing complex high-resolution geometries. Seeded C3H10T1/2 cells also showed over 95% viability with potential applications in biological studies. By combining biocompatible BFPs with 3D printing, novel safe and high-performance biomedical devices and healthcare products could be developed with broad long-term benefits to society.

Rotating carbon nanotube membrane filter for water desalination

Science.gov (United States)

Tu, Qingsong; Yang, Qiang; Wang, Hualin; Li, Shaofan

2016-01-01

We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based fine scale selective separation technology. PMID:27188982

Interactions between protein molecules and the virus removal membrane surface: Effects of immunoglobulin G adsorption and conformational changes on filter performance.

Science.gov (United States)

Hamamoto, Ryo; Ito, Hidemi; Hirohara, Makoto; Chang, Ryongsok; Hongo-Hirasaki, Tomoko; Hayashi, Tomohiro

2018-03-01

Membrane fouling commonly occurs in all filter types during virus filtration in protein-based biopharmaceutical manufacturing. Mechanisms of decline in virus filter performance due to membrane fouling were investigated using a cellulose-based virus filter as a model membrane. Filter performance was critically dependent on solution conditions; specifically, ionic strength. To understand the interaction between immunoglobulin G (IgG) and cellulose, sensors coated with cellulose were fabricated for surface plasmon resonance and quartz crystal microbalance with energy dissipation measurements. The primary cause of flux decline appeared to be irreversible IgG adsorption on the surface of the virus filter membrane. In particular, post-adsorption conformational changes in the IgG molecules promoted further irreversible IgG adsorption, a finding that could not be adequately explained by DLVO theory. Analyses of adsorption and desorption and conformational changes in IgG molecules on cellulose surfaces mimicking cellulose-based virus removal membranes provide an effective approach for identifying ways of optimizing solution conditions to maximize virus filter performance. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:379-386, 2018. © 2017 American Institute of Chemical Engineers.

The gamma radiation interaction with the polycarbonate Durolon

International Nuclear Information System (INIS)

Miranda, A.; Sciani, V.

1994-01-01

The effect of gamma irradiation on a polycarbonate Durolon, produced by the brazilian industries has been observed by means of stress-strain, transmittance and intrinsic viscosity measurements. The results obtained showed a good mechanical stability and that the degradation of polycarbonate increases with the water content during irradiation. (author). 8 refs, 5 figs, 1 tab

Effects of gamma radiation in mechanical and optical properties of polycarbonate

International Nuclear Information System (INIS)

Araujo, E.S.; Khoury, H.J.; Silveira, S.V. da; Dallolio, A.

1990-01-01

The polycarbonates are used in different industrial applications due to their excellent dielectric proprieties, impact resistance and high temperature resistance. For some of this applications, the polycarbonates are exposed to gamma radiation which produces a molecular scission, occasioning changes in the polycarbonate proprieties. To estimate the radiation effects in the DUROLON polycarbonate, samples were irradiated with sup(60)Co gamma beam with doses between 0,2kGy and 50kGy. The results obtained shown variations in the yellowness index above 1kGy dose. Their mechanical proprieties are not changed in the above dose interval. (author)

Modification of Low Refractive Index Polycarbonate for High Refractive Index Applications

Directory of Open Access Journals (Sweden)

Gunjan Suri

2009-01-01

Full Text Available Polycarbonates and polythiourethanes are the most popular materials in use today, for optical applications. Polycarbonates are of two types which fall in the category of low refractive index and medium refractive index. The present paper describes the conversion of low refractive index polycarbonates into high refractive index material by the use of a high refractive index monomer, polythiol, as an additive. Novel polycarbonates, where the properties of refractive index and Abbe number can be tailor made, have been obtained. Thermal studies and refractive index determination indicate the formation of a new polymer with improved properties and suitable for optical applications.

Gamma radiation effect study in polycarbonate optical and mechanics properties

International Nuclear Information System (INIS)

Araujo, E.S. de.

1991-02-01

Polycarbonates (PC) are used in different industrial applications due to their excellent dielectric characteristics, impact resistance, and high temperature resistance. In some of these applications, the polycarbonates are exposed to gamma radiation which produces molecular scissions, causing changes in the polycarbonate properties. To estimate the radiation effects in the Durolon polycarbonate, samples were irradiated with 60 Co gamma rays with doses between 0,2 kGy and 300 kGy. The results obtained showed that the PC mechanical properties are not changed due to the gamma radiation. However the results showed an expressive variation in the yellowness index for doses above 1 kGy. The results showed that it is possible to use the gamma sterilization of PC in applications where the coloration of PC is not critical. (author). 21 refs, 25 figs, 3 tabs

Filtration of Oil-furnace Carbon Black Dust Particles from the Tail Gases by Filter Bags With PTFE Membrane

Directory of Open Access Journals (Sweden)

Čuzela, D.

2010-01-01

Full Text Available During the industrial production of oil furnace carbon black, tail gases containing oil-furnace carbon black dust particles are emitted to the atmosphere. In the carbon black plant, Petrokemija d. d., there are six exhaust stacks for tail gases. Each of them has installed process equipment for cleaning tail gases. Efficiency of cleaning mainly depends on equipment construction and cleaning technology. The vicinity of the town, quality of the air in the region of Kutina, regarding floating particles PM10, and corporate responsibility for further enviromental improvement, imposes development of new methods that will decrease the emmision of oil-furnace carbon black dust particles in the air. Combining centrifugal percipitator and filter, special construction of cyclofilter for filtration of oil-furnace carbon black dust particles from tail gases by using PTFE (polytetrafluoroethylene membrane filter bags, was designed. Developed filtration technique provides η = 99.9 % efficiency of filtration. Construction part of the filter contains the newest generation of PTFE membrane filter bags with the ability of jet pulse cleaning. Using the PTFE membrane filter bags technology, filtration efficiency for oil-furnace carbon black dust particles in tail gases of maximum γ=5mgm-3can be achieved. The filtration efficiency was monitored continuously measuring the concentration of the oil-furnace carbon black dust particles in the tail gases with the help of in situ electronic probe. The accomplished filtration technology is the base for the installation of the PTFE membrane filter bags in the main operation filters which will provide better protection of the air in the town of Kutina against floating particles PM10.

Experimental and computational investigation of lateral gauge response in polycarbonate

Science.gov (United States)

Eliot, Jim; Harris, Ernst; Hazell, Paul; Appleby-Thomas, Gareth; Winter, Ronald; Wood, David; Owen, Gareth

2011-06-01

Polycarbonate's use in personal armour systems means its high strain-rate response has been extensively studied. Interestingly, embedded lateral manganin stress gauges in polycarbonate have shown gradients behind incident shocks, suggestive of increasing shear strength. However, such gauges need to be embedded in a central (typically) epoxy interlayer - an inherently invasive approach. Recently, research has suggested that in such metal systems interlayer/target impedance may contribute to observed gradients in lateral stress. Here, experimental T-gauge (Vishay Micro-Measurements® type J2M-SS-580SF-025) traces from polycarbonate targets are compared to computational simulations. This work extends previous efforts such that similar impedance exists between the interlayer and matrix (target) interface. Further, experiments and simulations are presented investigating the effects of a ``dry joint'' in polycarbonate, in which no encapsulating medium is employed.

Airborne Nanoparticle Detection By Sampling On Filters And Laser-Induced Breakdown Spectroscopy Analysis

Energy Technology Data Exchange (ETDEWEB)

Dewalle, Pascale; Sirven, Jean-Baptiste [CEA Saclay, DEN, Department of Physical Chemistry, F-91191 Gif-sur-Yvette (France); Roynette, Audrey; Gensdarmes, Francois [IRSN, DSU, Aerosol Physics and Metrology Laboratory, F-91192 Gif-sur-Yvette (France); Golanski, Luana; Motellier, Sylvie, E-mail: jean-baptiste.sirven@cea.fr [CEA Grenoble, DRT, LITEN, Laboratory of Nanomaterial Chemistry and Security, F-38054 Grenoble (France)

2011-07-06

Nowadays, due to their unique physical and chemical properties, engineered nanoparticles are increasingly used in a variety of industrial sectors. However, questions are raised about the safety of workers who produce and handle these particles. Therefore it is necessary to assess the potential exposure by inhalation of these workers. There is thereby a need to develop a suitable instrumentation which can detect selectively the presence of engineered nanoparticles in the ambient atmosphere. In this paper Laser-Induced Breakdown Spectroscopy (LIBS) is used to meet this target. LIBS can be implemented on site since it is a fast and direct technique which requires no sample preparation. The approach consisted in sampling Fe{sub 2}O{sub 3} and TiO{sub 2} nanoparticles on a filter, respectively a mixed cellulose ester membrane and a polycarbonate membrane, and to measure the surface concentration of Fe and Ti by LIBS. Then taking into account the sampling parameters (flow, duration, filter surface) we could calculate a detection limit in volume concentration in the atmosphere. With a sampling at 10 L/min on a 10 cm{sup 2} filter during 1 min, we obtained detection limits of 56 {mu}g/m{sup 3} for Fe and 22 {mu}g/m{sup 3} for Ti. These figures, obtained in real time, are significantly below existing workplace exposure recommendations of the EU-OSHA and of the NIOSH. These results are very encouraging and will be completed in a future work on airborne carbon nanotube detection.

Influence of size, shape, and flexibility on bacterial passage through micropore membrane filters.

Science.gov (United States)

Wang, Yingying; Hammes, Frederik; Düggelin, Marcel; Egli, Thomas

2008-09-01

Sterilization of fluids by means of microfiltration is commonly applied in research laboratories as well as in pharmaceutical and industrial processes. Sterile micropore filters are subject to microbiological validation, where Brevundimonas diminuta is used as a standard test organism. However, several recent reports on the ubiquitous presence of filterable bacteria in aquatic environments have cast doubt on the accuracy and validity of the standard filter-testing method. Six different bacterial species of various sizes and shapes (Hylemonella gracilis, Escherichia coli, Sphingopyxis alaskensis, Vibrio cholerae, Legionella pneumophila, and B. diminuta) were tested for their filterability through sterile micropore filters. In all cases, the slender spirillum-shaped Hylemonella gracilis cells showed a superior ability to pass through sterile membrane filters. Our results provide solid evidence that the overall shape (including flexibility), instead of biovolume, is the determining factor for the filterability of bacteria, whereas cultivation conditions also play a crucial role. Furthermore, the filtration volume has a more important effect on the passage percentage in comparison with other technical variables tested (including flux and filter material). Based on our findings, we recommend a re-evaluation of the grading system for sterile filters, and suggest that the species Hylemonella should be considered as an alternative filter-testing organism for the quality assessment of micropore filters.

Structural characterization of swift heavy ion irradiated polycarbonate

International Nuclear Information System (INIS)

Singh, Lakhwant; Samra, Kawaljeet Singh

2007-01-01

Makrofol-N polycarbonate thin films were irradiated with copper (50 MeV) and nickel (86 MeV) ions. The modified films were analyzed by UV-VIS, FTIR and XRD techniques. The experimental data was used to evaluate the formation of chromophore groups (conjugated system of bonds), degradation cross-section of the special functional groups, the alkyne formation and the amorphization cross-section. The investigation of UV-VIS spectra shows that the formation of chromophore groups is reduced at larger wavelength, however its value increases with the increase of ion fluence. Degradation cross-section for the different chemical groups present in the polycarbonate chains was evaluated from the FTIR data. It was found that there was an increase of degradation cross-section of chemical groups with the increase of electronic energy loss in polycarbonate. The alkyne and alkene groups were found to be induced due to swift heavy ion irradiation in polycarbonate. The radii of the alkyne production of about 2.74 and 2.90 nm were deduced for nickel (86 MeV) and copper (50 MeV) ions respectively. XRD analysis shows the decrease of the main XRD peak intensity. Progressive amorphization process of Makrofol-N with increasing fluence was traced by XRD measurements

Non-porous membrane-assisted liquid-liquid extraction of UV filter compounds from water samples.

Science.gov (United States)

Rodil, Rosario; Schrader, Steffi; Moeder, Monika

2009-06-12

A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes non-porous membrane-assisted liquid-liquid extraction (MALLE) and LC-atmospheric pressure photoionization (APPI)-MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made membrane bags were prepared from low-density polyethylene in order to accommodate 100 microL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L(-1) (OD-PABA) and 16 ng L(-1) (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L(-1) (BP-3) and 4381 ng L(-1) (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L(-1) (OC).

Rapid antibiotic efficacy screening with aluminum oxide nanoporous membrane filter-chip and optical detection system.

Science.gov (United States)

Tsou, Pei-Hsiang; Sreenivasappa, Harini; Hong, Sungmin; Yasuike, Masayuki; Miyamoto, Hiroshi; Nakano, Keiyo; Misawa, Takeyuki; Kameoka, Jun

2010-09-15

We have developed a filter-chip and optical detection system for rapid antibiotic efficacy screening. The filter-chip consisted of a 1-mL reservoir and an anodic aluminum oxide (AAO) nanoporous membrane. Sample solution with liquid growth media, bacteria, and antibiotics was incubated in the reservoir for a specific period of time. The number of live bacteria on the surface of membrane was counted after the incubation with antibiotics and filtration. Using this biosensing system, we have demonstrated a 1-h antibiotic screening for patients' clinical samples, significantly faster than the conventional antibiotic susceptibility tests that typically take more than 24h. This rapid screening nature makes the filter-chip and detection system ideal for tailoring antibiotic treatment to individual patients by reducing the microbial antibiotic resistance, and improving the survival rate for patients suffering from postoperative infections. Published by Elsevier B.V.

Study of loading/air back-pulse cleaning cycles on the performance of ceramic membrane filters

International Nuclear Information System (INIS)

Waggoner, Charles; Alderman, Steven; Parsons, Michael; Hogoncamp, Kristina; Alderman, Steven

2007-01-01

Available in abstract form only. Full text of publication follows: The most commonly identified threats to conventional glass fiber HEPA filter performance are moisture and rapid blinding of filters by smoke. Regenerable filter media composed of ceramics or sintered metal can be utilized as pre-filters to protect the more vulnerable glass fiber HEPA filters in the event of upset conditions. Additionally, used in a pre-filtering application, the use of these regenerable filters can potentially extend the lifetime of conventional units. A series of tests have been conducted using CeraMem ceramic membrane filters in an effort to evaluate their performance after repeated loading and air back pulse cleaning. This was done in an effort to access filter performance after repeated loading/cleaning cycles. The filters were loaded using a solid potassium chloride aerosol challenge. The filters were evaluated for pressure drop and filtering efficiency changes from one cleaning cycle to the next. Additionally, the particle size distribution of the aerosol penetrating the filters was measured. (authors)

Extractable substances (anionic surfactants) from membrane filters induce morphological changes in the green alga Scenedesmus obliquus (Chlorophyceae)

NARCIS (Netherlands)

Lürling, M.; Beekman, W.

2002-01-01

The effect of filtration of medium through different kinds of filters (glass fiber, mixed esters of cellulose and nitrocellulose) on the morphology in the green alga Scenedesmus obliquus was examined. Several compounds potentially released from membrane filters were further investigated, and among

Photodegradation of bisphenol A polycarbonate

NARCIS (Netherlands)

Diepens, M.; Gijsman, P.

2007-01-01

When bisphenol A polycarbonate is subjected to weathering conditions this polymer shows two different degradation mechanisms depending on the used irradiation wavelengths, i.e. photo-oxidation and photo-Fries rearrangement. The relative importance of these mechanisms in outdoor exposure conditions

Microscopic hydrodynamics study with nuclear track membrane

International Nuclear Information System (INIS)

Shilun Guo; Yuhua Zhao; Yulan Wang; Hiuhong Hao; Brandt, R.; Vater, P.

1988-01-01

Microscopic hydrodynamics has been studied using different liquids and nuclear track membranes with pores perpendicularly piercing through them. The flow rate of water and alcohol has been studied with polycarbonate track membranes with pore diameters 1.48 micrometres and 1.08 micrometres. It has been shown that the flow rate both for water and alcohol on a microscopic scale can be determined by the Poiseuille law which characterizes macroscopic laminar flow. The Reynolds number used in macroscopic fluid flow has been calculated from the flow rate and parameters of the liquids and the geometry of the pores. It has been shown that this Reynolds number can also be used to characterize microscopic flow. Based on the above results, the filtration capacity (or limit) of polycarbonate track microfilters for water had been calculated. Some possible limits on the application of the calculation are pointed out and discussed. (author)

Ion permeability of artificial membranes evaluated by diffusion potential and electrical resistance measurements.

Science.gov (United States)

Shlyonsky, Vadim

2013-12-01

In the present article, a novel model of artificial membranes that provides efficient assistance in teaching the origins of diffusion potentials is proposed. These membranes are made of polycarbonate filters fixed to 12-mm plastic rings and then saturated with a mixture of creosol and n-decane. The electrical resistance and potential difference across these membranes can be easily measured using a low-cost volt-ohm meter and home-made Ag/AgCl electrodes. The advantage of the model is the lack of ionic selectivity of the membrane, which can be modified by the introduction of different ionophores to the organic liquid mixture. A membrane treated with the mixture containing valinomycin generates voltages from -53 to -25 mV in the presence of a 10-fold KCl gradient (in to out) and from -79 to -53 mV in the presence of a bi-ionic KCl/NaCl gradient (in to out). This latter bi-ionic gradient potential reverses to a value from +9 to +20 mV when monensin is present in the organic liquid mixture. Thus, the model can be build stepwise, i.e., all factors leading to the development of diffusion potentials can be introduced sequentially, helping students to understand the quantitative relationships of ionic gradients and differential membrane permeability in the generation of cell electrical signals.

Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

Directory of Open Access Journals (Sweden)

Yongyao Chen

2012-06-01

Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

CO₂ Capture Membrane Process for Power Plant Flue Gas

Energy Technology Data Exchange (ETDEWEB)

Toy, Lora [Research Triangle Inst. International, Research Triangle Park, NC (United States); Kataria, Atish [Research Triangle Inst. International, Research Triangle Park, NC (United States); Gupta, Raghubir [Research Triangle Inst. International, Research Triangle Park, NC (United States)

2012-04-01

Because the fleet of coal-fired power plants is of such importance to the nation's energy production while also being the single largest emitter of CO₂, the development of retrofit, post-combustion CO₂ capture technologies for existing and new, upcoming coal power plants will allow coal to remain a major component of the U.S. energy mix while mitigating global warming. Post-combustion carbon capture technologies are an attractive option for coal-fired power plants as they do not require modification of major power-plant infrastructures, such as fuel processing, boiler, and steam-turbine subsystems. In this project, the overall objective was to develop an advanced, hollow-fiber, polymeric membrane process that could be cost-effectively retrofitted into current pulverized coal-fired power plants to capture at least 90% of the CO₂ from plant flue gas with 95% captured CO₂ purity. The approach for this project tackled the technology development on three different fronts in parallel: membrane materials R&D, hollow-fiber membrane module development, and process development and engineering. The project team consisted of RTI (prime) and two industrial partners, Arkema, Inc. and Generon IGS, Inc. Two CO₂-selective membrane polymer platforms were targeted for development in this project. For the near term, a next-generation, high-flux polycarbonate membrane platform was spun into hollow-fiber membranes that were fabricated into both lab-scale and larger prototype (~2,200 ft²) membrane modules. For the long term, a new fluoropolymer membrane platform based on poly(vinylidene fluoride) [PVDF] chemistry was developed using a copolymer approach as improved capture membrane materials with superior chemical resistance to flue-gas contaminants (moisture, SO₂, NO_x, etc.). Specific objectives were: - Development of new, highly chemically resistant, fluorinated polymers as membrane materials with minimum selectivity of 30 for CO₂ over N₂ and CO�

Preparation of Track Etch Membrane Filters Using Polystyrene Film

International Nuclear Information System (INIS)

Kaewsaenee, Jerawut; Ratanatongchai, Wichian; Supaphol, Pitt; Visal-athaphand, Pinpan

2007-08-01

Full text: Polystyrene nuclear track etch membrane filters was prepared by exposed 13 .m thin film polystyrene with fission fragment. Nuclear latent track was enlarged to through hole on the film by etching with 80 o C 40% H 2 SO 4 with K 2 Cr 2 O 7 solution for 6-10 hour. The hole size was depend on concentration of etching solution and etching time with 1.3-3.4 .m hole diameter. The flow rate test of water was 0.79-1.56 mm cm-2 min-1 at 109.8-113.7 kPa pressure

Electron spin resonance investigations on polycarbonate irradiated with U ions

Energy Technology Data Exchange (ETDEWEB)

Chipara, M.I.; Reyes-Romero, J

2001-12-01

Electron spin resonance investigations on polycarbonate irradiated with uranium ions are reported. The dependence of the resonance line parameters (line intensity, line width, double integral) on penetration depth and dose is studied. The nature of free radicals induced in polycarbonate by the incident ions is discussed in relation with the track structure. The presence of severe exchange interactions among free radicals is noticed.

Degradation of polycarbonate induced by gamma radiation

International Nuclear Information System (INIS)

Araujo, E.S. de; Guedes, S.M.L.

1992-01-01

Polycarbonate (PC) DUROLON amorphous, of molecular weight 22000 g/mol is used in medical supplies and may be sterilized by gamma radiation. The main chain scission and polymer degradation occur when this polymer is irradiated. The value G = 1.54 to DUROLON was obtained by equation: 10 6 /M v = 10 6 /M v' + 0.054 G R. The degradation without crosslinking it is not general rule to all types of polycarbonates; an comparison was realized. The infrared (FT-IR) spectra of irradiated PC by gamma rays with different doses showed the main chain scissions in carbonyl groups. The mechanism of polymeric degradation to DUROLON, observed by NMR spectra, is a recombination of phenoxy and phenyl radicals. (author)

DLC-Si protective coatings for polycarbonates

Directory of Open Access Journals (Sweden)

Damasceno J.C.

2003-01-01

Full Text Available In this work, a-C:H:Si (DLC-Si films were produced onto crystalline silicon and polycarbonate substrates by the rf-PACVD technique from gaseous mixtures of CH4 + SiH4 and C2H2 + SiH4. The effects of self-bias and gas composition upon mechanical and optical properties of the films were investigated. Micro-hardness, residual stress, surface roughness and refractive index measurements were employed for characterization. By incorporating low concentrations of silicon and by exploring the more favorable conditions for the rf-PACVD deposition technique, highly adherent DLC-Si thin films were produced with reduced internal stresses (lower than 1 GPa, high hardness (around 20 GPa and high deposition rates (up to 10 µm/h. Results that show the technological viability of this material for application as protective coatings for polycarbonates are also discussed.

Radiolytic degradation and stability of polycarbonate

International Nuclear Information System (INIS)

Araujo, E.S. de.

1993-01-01

The radiolytic stability of polycarbonate was studied using national commercial additives, employed in the photo and thermo-oxidative stabilization of polymers. Among several additives tested only two showed the efficiency to radiolytic protection: one quencher and one radical scavenger. It was derived a linear relation that provides by slope of the straight line the degree of degradation (scissions), G, and the factors of radiolytic protection P (degree of protection) and CE (capture of energy) conferred by radioprotector additive easily. Therefore the method developed in this work (viscosity) to study the molecular degradation and stability of polymers is a simply and precise method. The synergic mixture of two additives (1% of weight total) confers at polycarbonate excellent radiolytic protection of 98% (20 - 40 kGy) reducing the G value of 16.7 to only 0.4. (author). 69 refs, 31 figs, 17 tabs

An experimental study of the fabrication of polycarbonate optical waveguides

Science.gov (United States)

Chen, Jianguo; Zhang, Xiao-yang; Zhang, Tong; Zhu, Jing-song; Wu, Peng-qin; Zhou, Jing-lun; Fan, Jiang-feng; Yan, Hao-feng

2008-12-01

A novel polycarbonate (PC) was introduced to apply in the optical waveguide devices. PC has following distinct merits than common polycarbonate: good processability, high thermal stability up to 293 C° and high optical transparency. Optical properties of absorption behavior and propagation loss were investigated in slab waveguides, and low propagation losses of 0.335 dB/cm (@1550nm) and 0.197 dB/cm @632.8nm) have been achieved by using prismcoupler. Additionally, straight optical waveguide and MMI coupler of ring resonator were fabricated using ultraviolet (UV) cured resin Norland optical adhesive 61 (NOA61) as under or upper cladding layer and polycarbonate as waveguide core-layer material through conventional methods such as spin coating, photolithography and reactive ion etching (RIE). The process was studied in detail and the experimental results were given.

Bisphenol A is released from used polycarbonate animal cages into water at room temperature

Science.gov (United States)

Howdeshell, Kembra L.; Peterman, Paul H.; Judy, Barbara M.; Taylor, Julia A.; Orazio, Carl E.; Ruhlen, Rachel L.; vom Saal, Frederick S.; Welshons, Wade V.

2003-01-01

Bisphenol A (BPA) is a monomer with estrogenic activity that is used in the production of food packaging, dental sealants, polycarbonate plastic, and many other products. The monomer has previously been reported to hydrolyze and leach from these products under high heat and alkaline conditions, and the amount of leaching increases as a function of use. We examined whether new and used polycarbonate animal cages passively release bioactive levels of BPA into water at room temperature and neutral pH. Purified water was incubated at room temperature in new polycarbonate and polysulfone cages and used (discolored) polycarbonate cages, as well as control (glass and used polypropylene) containers. The resulting water samples were characterized with gas chromatography/mass spectrometry (GC/MS) and tested for estrogenic activity using an MCF-7 human breast cancer cell proliferation assay. Significant estrogenic activity, identifiable as BPA by GC/MS (up to 310 micro g/L), was released from used polycarbonate animal cages. Detectable levels of BPA were released from new polycarbonate cages (up to 0.3 micro g/L) as well as new polysulfone cages (1.5 micro g/L), whereas no BPA was detected in water incubated in glass and used polypropylene cages. Finally, BPA exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages, although the difference was not statistically significant. Our findings suggest that laboratory animals maintained in polycarbonate and polysulfone cages are exposed to BPA via leaching, with exposure reaching the highest levels in old cages.

Surface modification and metallization of polycarbonate using low energy ion beam

International Nuclear Information System (INIS)

Reheem, A.M. Abdel; Maksoud, M.I.A. Abdel; Ashour, A.H.

2016-01-01

The low energy argon ion is used for irradiation polycarbonate samples using cold cathode ion source. The surface of the PC substrates is examined using SEM, UV-spectroscopy and FTIR. It was found that the energy band gap decrease by increase argon ion fluence. Copper films are deposited onto polycarbonate (PC) substrates after irradiation by argon ion beam. The structure, surface morphology and the optical band gap are investigated using XRD, SEM and UV spectroscopy. It can be seen that the intensity increases with deposition time and band gap decreases from 3.45 eV for the pristine PC to ∼1.7 eV for copper thin film. - Highlights: • The low energy argon ion is used for irradiation polycarbonate samples. • The surface roughness increase from 9 µm to 23.5 µm after argon ion irradiated. • Copper films are deposited onto polycarbonate (PC) substrates. • Energy band gap decreases from 3.45 eV for pristine to 1.7 eV for copper thin film.

Characteristics of 5 mol% Ce{sup 3+}-doped barium titanate nanowires prepared by a combined route involving sol–gel chemistry and polycarbonate membrane-templated process

Energy Technology Data Exchange (ETDEWEB)

Vasilescu, Catalina-Andreea [University POLITEHNICA of Bucharest, Department of Oxide Materials Science and Engineering (Romania); Trupina, Lucian [National Institute of Materials Physics (Romania); Vasile, Bogdan Stefan [University POLITEHNICA of Bucharest, Department of Oxide Materials Science and Engineering (Romania); Trusca, Roxana [S.C. METAV–Research & Development Bucharest (Romania); Cernea, Marin [National Institute of Materials Physics (Romania); Ianculescu, Adelina-Carmen, E-mail: a-ianculescu@yahoo.com [University POLITEHNICA of Bucharest, Department of Oxide Materials Science and Engineering (Romania)

2015-11-15

Ba{sub 0.95}Ce{sub 0.05}Ti{sub 0.9875}O{sub 3} nanowires were fabricated by sol–gel method using as template a polycarbonate membrane with channels of 100 nm diameter. FE-SEM analyses showed that continuous gel wires of length up to 17 µm and an average diameter of 81 nm, were obtained. After calcination at 700 °C for 1 h, these green 1D nanostructures were converted into well-crystallised wires with an average diameter of 59.7 nm, as high-resolution transmission electron microscopy and selected area electron diffraction indicated. The piezoelectric activity of the Ba{sub 0.95}Ce{sub 0.05}Ti{sub 0.9875}O{sub 3} nanowires was investigated using piezoresponse force microscopy (PFM) correlated with atomic force microscopy. The results of PFM measurements indicated that the wires exhibit a significant fraction of ferroelectric domains larger than the grains size and a good piezoelectric response.

Excimer laser beam profile recording based on electrochemical etched polycarbonate

International Nuclear Information System (INIS)

Parvin, P.; Jaleh, B.; Zangeneh, H.R.; Zamanipour, Z.; Davoud-Abadi, Gh.R.

2008-01-01

There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler

Excimer laser beam profile recording based on electrochemical etched polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Parvin, P. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of)], E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu-Ali Sina University, Postal Code 65174, Hamedan (Iran, Islamic Republic of); Zangeneh, H.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Zamanipour, Z. [Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of); Davoud-Abadi, Gh.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of)

2008-08-15

There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler.

Degradation study of Durolon polycarbonate submitted to gamma radiation

International Nuclear Information System (INIS)

Miranda, A.; Sciani, V.

1992-01-01

The effect of gamma radiation from a cobalt 60 source in the 27000 Durolon polycarbonate irradiated with doses between 0,2 and 1000 kGy at 25 0 C was analyzed. For this reason the samples was submitted to the mechanical assay of tension, deformation and hardness and optical assay of transmittance. The obtained results show a good mechanical stability of the polycarbonate, when it was submitted to gamma irradiation in doses up to 20 kGy. (C.G.C.). 05 refs., 04 figs

Polycarbonate radiolytic degradation and stabilization

International Nuclear Information System (INIS)

Araujo, E.S. de

1994-01-01

Polycarbonate Durolon, useful for medical supplies fabrication, is submitted to gamma radiation for sterilization purposes. Scissions in main chain occur, in carbonyl groups, producing molecular degradations and yellowness. The radiolytic stabilization is obtained through additive to the polymer. In this work some degradation and stabilization aspects are presented. (L.C.J.A.). 7 refs, 7 figs, 2 tabs

Profile of an epidemiological study of urinary schistosomiasis in two ...

African Journals Online (AJOL)

Aim: This study was conducted in an attempt to establish the prevalence of urinary schistosomiasis in relation to epidemiological factors among children in Buruku and Katsina-Ala local government areas, Benue, Nigeria. Materials and Methods: Urine filtration technique using polycarbonate membrane filters was employed ...

Migration of bisphenol A into water from polycarbonate baby bottles during microwave heating

NARCIS (Netherlands)

Ehlert, K.A.; Beumer, C.W.E.; Groot, M.C.E.

2008-01-01

A comprehensive migration database was established for bisphenol A from polycarbonate baby bottles into water during exposure to microwave heating. Eighteen different brands of polycarbonate baby bottles sold in Europe were collected. Initial residual content of bisphenol A and migration after

Cytotoxic effects of polycarbonate-based orthodontic brackets by activation of mitochondrial apoptotic mechanisms

NARCIS (Netherlands)

Kloukos, D.; Taoufik, E.; Eliades, T.; Katsaros, C.; Eliades, G.

2013-01-01

OBJECTIVES: The aim of the study was to evaluate the biological effects of water eluents from polycarbonate based esthetic orthodontic brackets. METHODS: The composite polycarbonate brackets tested were Silkon Plus (SL, fiber-glass-reinforced), Elan ME (EL, ceramic particle-reinforced) and Elegance

Polypropylene and polycarbonate radiosterilization: effects on the stress resistance

International Nuclear Information System (INIS)

Musico Filho, W.; Terence, M.C.; Guedes, S.M.L.; Araujo, E.S. de

1994-01-01

The gamma radiation effect on polymer sterilization used in the fabrication of medical supplies, national polycarbonate and polypropylene, was studied in function of the tensile strength. During the polycarbonate irradiation occur the scission of polymer chain and the crosslinking/scission of the polypropylene, but in the sterilization dose, 25 kGy, does not occur expressive changes in the tensile strength. After the polypropylene sterilization the tensile strength continues increasing as consequence of the crosslinking. Since the sixth day the oxidation reaction predominates as consequence of the radical migration to the amorphous region. (author). 7 refs, 6 figs

Influence of nanoparticles on filterability of fruit-juice industry wastewater using submerged membrane bioreactor.

Science.gov (United States)

Demirkol, Guler Turkoglu; Dizge, Nadir; Acar, Turkan Ormanci; Salmanli, Oyku Mutlu; Tufekci, Nese

2017-07-01

In this study, polyethersulfone (PES) ultrafiltration membrane surface was modified with nano-sized zinc oxide (nZnO) and silver (nAg) to improve the membrane filterability of the mixed liquor and used to treat fruit-juice industry wastewater in a submerged membrane bioreactor (MBR). The nAg was synthesized using three different methods. In the first method, named as nAg-M1, PES membrane was placed on the membrane module and nAg solution was passed through the membrane for 24 h at 25 ± 1 °C. In the second method, named as nAg-M2, PES membrane was placed in a glass container and it was shaken for 24 h at 150 rpm at 25 ± 1 °C. In the third method, named as nAg-M3, Ag nanoparticles were loaded onto PES membrane in L-ascorbic acid solution (0.1 mol/L) at pH 2 for 24 h at 150 rpm at 25 ± 1 °C. For the preparation of nZnO coated membrane, nZnO nanoparticles solution was passed through the membrane for 24 h at 25 ± 1 °C. Anti-fouling performance of pristine and coated membranes was examined using the submerged MBR. The results showed that nZnO and nAg-M3 membranes showed lower flux decline compared with pristine membrane. Moreover, pristine and coated PES membranes were characterized using a permeation test, contact angle goniometer, and scanning electron microscopy.

Measurements of diffusion parameters of methanol on gamma-irradiated polycarbonate

International Nuclear Information System (INIS)

Silva, Pietro P.J.C.G.P.O.; Araujo, Elmo S.

2013-01-01

Polycarbonate (PC) is an engineering polymer which presents interesting properties such as toughness, light weight and transparency. This material has been used for several important applications including in the medical field. In this particular application, polycarbonate has been exposed frequently to gamma irradiation and to chemical environment that can be able to product significant changes in polymer structure that may lead to future catastrophic fail and rupture. Polymer structural damages induced by gamma irradiation or chemical attack (environment stress cracking) have been studied by several research groups for many years and for many solvent-polymer systems, but few reporters present informations about the simultaneous occurrence of these effects. This present work has the goal to understand the diffusion process of methanol in polycarbonate and to determinate the diffusion parameters on polymer system under 100 kGy of gamma irradiation. Swelling experiments were performed at the samples of polycarbonate divided in two groups: PC-0 (without dose) and PC-100 (with 100 kGy of dose). Diffusion parameters (D) may be measured by slope of the sorption curve for polymers with Fickian behavior. A comparison of the D parameters was made for each set of sample. There were no significant differences on D values of sample groups observed due to the radiation effects. However, stress strain curves obtained show that methanol has great influence on mechanical behavior of PC but the radiation dose don't have significant influence on this mechanical behavior. (author)

Performance of zeolite ceramic membrane synthesized by wet mixing method as methylene blue dye wastewater filter

Science.gov (United States)

Masturi; Widodo, R. D.; Edie, S. S.; Amri, U.; Sidiq, A. L.; Alighiri, D.; Wulandari, N. A.; Susilawati; Amanah, S. N.

2018-03-01

Problem of pollution in water continues in Indonesia, with its manufacturing sector as biggest contributor to economic growth. One out of many technological solutions is post-treating industrial wastewater by membrane filtering technology. We presented a result of our fabrication of ceramic membrane made from zeolite with simple mixing and he. At 5% of (poring agent):(total weight), its permeability stays around 2.8 mD (10‑14m2) with slight variance around it, attributed to the mixture being in far below percolating threshold. All our membranes achieve remarkable above 90% rejection rate of methylene blue as solute waste in water solvent.

Constitutive modeling of polycarbonate over a wide range of strain rates and temperatures

Science.gov (United States)

Wang, Haitao; Zhou, Huamin; Huang, Zhigao; Zhang, Yun; Zhao, Xiaoxuan

2017-02-01

The mechanical behavior of polycarbonate was experimentally investigated over a wide range of strain rates (10^{-4} to 5× 103 s^{-1}) and temperatures (293 to 353 K). Compression tests under these conditions were performed using a SHIMADZU universal testing machine and a split Hopkinson pressure bar. Falling weight impact testing was carried out on an Instron Dynatup 9200 drop tower system. The rate- and temperature-dependent deformation behavior of polycarbonate was discussed in detail. Dynamic mechanical analysis (DMA) tests were utilized to observe the glass (α ) transition and the secondary (β ) transition of polycarbonate. The DMA results indicate that the α and β transitions have a dramatic influence on the mechanical behavior of polycarbonate. The decompose/shift/reconstruct (DSR) method was utilized to decompose the storage modulus into the α and β components and extrapolate the entire modulus, the α-component modulus and the β-component modulus. Based on three previous models, namely, Mulliken-Boyce, G'Sell-Jonas and DSGZ, an adiabatic model is proposed to predict the mechanical behavior of polycarbonate. The model considers the contributions of both the α and β transitions to the mechanical behavior, and it has been implemented in ABAQUS/Explicit through a user material subroutine VUMAT. The model predictions are proven to essentially coincide with the experimental results during compression testing and falling weight impact testing.

Thermal analysis of used and radiation treated polycarbonate (L-MW) biomaterial

International Nuclear Information System (INIS)

Jayabalan, M.; Sreenivasan, K.; Nair, P.D.; Jalajamani, K.V.

1988-01-01

γ-radiation treatment of radiation sterilized polycarbonate biomaterials has been carried out to ensure efficient disposal by incineration. Low molecular weight polycarbonate sterilized with 2.5 Mrad dose of γ-radiation was further treated with different doses of γ-radiation. The radiation-treated samples were subjected to thermogravimetry. The sterilized sample and the 7.5 Mrad-treated sample showed similar properties. These samples do not leave any residue during thermal decomposition. (author). 5 refs., 3 tables

Design and fabrication of ultrathin silicon-nitride membranes for use in UV-visible airgap-based MEMS optical filters

International Nuclear Information System (INIS)

Ghaderi, Mohammadamir; Wolffenbuttel, Reinoud F.

2016-01-01

MEMS-based airgap optical filters are composed of quarter-wave thick high-index dielectric membranes that are separated by airgaps. The main challenge in the fabrication of these filters is the intertwined optical and mechanical requirements. The thickness of the layers decreases with design wavelength, which makes the optical performance in the UV more susceptible to fabrication tolerances, such as thickness and composition of the deposited layers, while the ability to sustain a certain level of residual stress by the structural strength becomes more critical. Silicon-nitride has a comparatively high Young's modulus and good optical properties, which makes it a suitable candidate as the membrane material. However, both the mechanical and optical properties in a silicon-nitride film strongly depend on the specifics of the deposition process. A design trade-off is required between the mechanical strength and the index of refraction, by tuning the silicon content in the silicon-nitride film. However, also the benefit of a high index of refraction in a silicon-rich film should be weighed against the increased UV optical absorption. This work presents the design, fabrication, and preliminary characterization of one and three quarter-wave thick silicon-nitride membranes with a one-quarter airgap and designed to give a spectral reflectance at 400 nm. The PECVD silicon-nitride layers were initially characterized, and the data was used for the optical and mechanical design of the airgap filters. A CMOS compatible process based on polysilicon sacrificial layers was used for the fabrication of the membranes. Optical characterization results are presented. (paper)

Technical feasibility study on polycarbonate solar panels

NARCIS (Netherlands)

Hackmann, M.M.; Meuwissen, M.H.H.; Bots, T.L.; Buijs, J.A.H.M.; Broek, K.M.; Kinderman, R.; Tanck, O.B.F.; Schuurmans, F.M.

2004-01-01

This paper describes a technical feasibility study on the application of polycarbonate (PC) plates in a superstrate photovoltaic module design. The lamination process was performed in a conventional laminator apparatus using low temperature curing (100°C) ethylene-vinyl-acetate (EVA) as the potting

Membrane filtration of nickel(II) on cellulose acetate filters for its preconcentration, separation, and flame atomic absorption spectrometric determination

Energy Technology Data Exchange (ETDEWEB)

Soylak, Mustafa [Chemistry Dept., Faculty of Science Arts, University of Erciyes, Kayseri (Turkey); Unsal, Yunus Emre; Aydin, Ayse [Fen Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey); Kizil, Nebiye [Saglik Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey)

2010-01-15

An enrichment method for trace amounts of Ni(II), as 8-hydroxyquinoline chelates, has been established on a cellulose acetate membrane filter. Ni(II)-8-hydroxyquinoline chelates adsorbed on a membrane filter were eluted using 5 mL of 1 M HNO{sub 3}. The eluent nickel concentration was determined by a flame atomic absorption spectrometer. The influence of some analytical parameters, including pH, amount of reagent, sample volume, etc., on recovery was investigated. The interference of co-existent ions was studied. The nickel detection limit was 4.87 {mu}g/L. The method was applied to real samples for the determination of nickel(II) ions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Effect of Biological Contact Filters (BCFs on Membrane Fouling in Drinking Water Treatment Systems

Directory of Open Access Journals (Sweden)

Susumu Hasegawa

2017-12-01

Full Text Available Membrane fouling is a serious problem in drinking water treatment systems. Biological contact filters (BCFs are often used as a pretreatment to remove ammonia, dissolved organic matter (DOM, and metal ions such as iron and manganese. In this study, the effect of BCF as a pretreatment for membrane fouling was evaluated using a laboratory-scale mini module consisting of a mini BCF column and a mini MF column. Initially, it was confirmed that the main foulant was a biopolymer (at low concentration in the raw water. Subsequently, the biopolymer concentrations in the BCF influent and effluent were measured with the excitation emission matrix (EEM fluorescence spectroscopy and the liquid chromatograph organic carbon detector (LC-OCD. The fouling potential of the BCF influent and effluent was also measured to evaluate MF membrane fouling rate. The results demonstrate that application of the BCF reduced the biopolymer concentration of the effluent and reduced membrane fouling. The effect of BCF was also established in an actual drinking water treatment plant. It was found that optimizing the contact time of raw water with the BCF was crucial to reduce membrane fouling.

A Universal Platform for Identification of Novel Lung Cancer Biomarkers Based on Exosomes

Science.gov (United States)

2017-10-01

plastic layers, a polycarbonate track-etched nanoporous filter membrane, polyethersulfone (PES) layer, and cellulose pad. The plastic housing is...secured with metal screws and nuts and a plastic ring-shaped gasket provides a leak-free seal. The cellulose pad prevents deformation of the filter...Figure 3c). The forty most highly expressed microRNAs were common (100% overlap) to both EV isolation methods. The Venn diagram in Figure 3d for two

Migration of 2-butoxyethyl acetate from polycarbonate infant feeding bottles

DEFF Research Database (Denmark)

Petersen, Jens Højslev; Lund, K.H.

2003-01-01

An enforcement campaign was carried out to assess the migration of 2-butoxyethyl acetate (2-BEA) from polycarbonate infant feeding bottles intended for repeated use. Migration was measured by three successive migration tests into two of the European Union official food simulants: distilled water......-BEA was found from eight of 12 bottles. However, migration above the target value of 0.33 mg kg(-1) was not observed in the third decisive test from any of the 12 different brands of polycarbonate feeding bottles. A migration of between 0.05 and 0.26 mg kg(-1) from seven of 12 bottles was measured...

Micromechanisms of fatigue crack growth in polycarbonate polyurethane: Time dependent and hydration effects.

Science.gov (United States)

Ford, Audrey C; Gramling, Hannah; Li, Samuel C; Sov, Jessica V; Srinivasan, Amrita; Pruitt, Lisa A

2018-03-01

Polycarbonate polyurethane has cartilage-like, hygroscopic, and elastomeric properties that make it an attractive material for orthopedic joint replacement application. However, little data exists on the cyclic loading and fracture behavior of polycarbonate polyurethane. This study investigates the mechanisms of fatigue crack growth in polycarbonate polyurethane with respect to time dependent effects and conditioning. We studied two commercially available polycarbonate polyurethanes, Bionate® 75D and 80A. Tension testing was performed on specimens at variable time points after being removed from hydration and variable strain rates. Fatigue crack propagation characterized three aspects of loading. Study 1 investigated the impact of continuous loading (24h/day) versus intermittent loading (8-10h/day) allowing for relaxation overnight. Study 2 evaluated the effect of frequency and study 3 examined the impact of hydration on the fatigue crack propagation in polycarbonate polyurethane. Samples loaded intermittently failed instantaneously and prematurely upon reloading while samples loaded continuously sustained longer stable cracks. Crack growth for samples tested at 2 and 5Hz was largely planar with little crack deflection. However, samples tested at 10Hz showed high degrees of crack tip deflection and multiple crack fronts. Crack growth in hydrated samples proceeded with much greater ductile crack mouth opening displacement than dry samples. An understanding of the failure mechanisms of this polymer is important to assess the long-term structural integrity of this material for use in load-bearing orthopedic implant applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of gamma irradiation on the etching properties of Lexan and Makrofol-DE polycarbonate plastics

International Nuclear Information System (INIS)

Ashok Kumar; Jain, R.K.; Praveen Yadav; Chakraborty, R.N.; Singh, B.K.; Nayak, B.K.

2013-01-01

It is observed that for Lexan and Makrofol-DE polycarbonate plastic detectors the mean diameters of fission fragments from a 252 Cf source increases as a result of gamma-ray exposure. We have studied the bulk etching rate and track etching rate before and after gamma-ray irradiation on Lexan and Makrofol-DE polycarbonate plastics. The mechanism of Lexan and Makrofol-DE polycarbonate plastic detectors can be understood with the help of this exposures. It is also noted that degree of ordering of Lexan and Makrofol-DE polycarbonate is dependent on the gamma ray dose due to degradation and cross-linking processes. The results show that bulk and track etch rate increases with gamma dose while activation energy associated with bulk and track etch rates at a particular temperature and sensitivity decreases with gamma dose. (author)

Evaluation of Alternative Filter Media for the Rotary Microfilter

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. R.; Herman, D. T.; Bhave, R.

2011-11-09

The Savannah River Site is currently developing and testing several processes to treat high level radioactive liquid waste. Each of these processes has a solid-liquid separation process that limits its throughput. Savannah River National Laboratory researchers identified and tested the rotary microfilter as a technology to increase solid-liquid separation throughput. The authors believe the rotary microfilter throughput can be improved by using a better filter membrane. Previous testing showed that asymmetric filters composed of a ceramic membrane on top of a stainless steel support produced higher filter flux than 100% stainless steel symmetric filters in crossflow filter tests. Savannah River National Laboratory and Oak Ridge National Laboratory are working together to develop asymmetric ceramic ? stainless steel composite filters and asymmetric 100% stainless steel filters to improve the throughput of the rotary microfilter. The Oak Ridge National Laboratory Inorganic Membrane Group fabricated samples of alternative filter membranes. In addition, Savannah River National Laboratory obtained samples of filter membranes from Pall, Porvair, and SpinTek. They tested these samples in a static test cell with feed slurries containing monosodium titanate and simulated sludge.

Evaluation of Alternative Filter Media for the Rotary Microfilter

International Nuclear Information System (INIS)

Poirier, M. R.; Herman, D. T.; Bhave, R.

2011-01-01

The Savannah River Site is currently developing and testing several processes to treat high level radioactive liquid waste. Each of these processes has a solid-liquid separation process that limits its throughput. Savannah River National Laboratory researchers identified and tested the rotary microfilter as a technology to increase solid-liquid separation throughput. The authors believe the rotary microfilter throughput can be improved by using a better filter membrane. Previous testing showed that asymmetric filters composed of a ceramic membrane on top of a stainless steel support produced higher filter flux than 100% stainless steel symmetric filters in crossflow filter tests. Savannah River National Laboratory and Oak Ridge National Laboratory are working together to develop asymmetric ceramic-stainless steel composite filters and asymmetric 100% stainless steel filters to improve the throughput of the rotary microfilter. The Oak Ridge National Laboratory Inorganic Membrane Group fabricated samples of alternative filter membranes. In addition, Savannah River National Laboratory obtained samples of filter membranes from Pall, Porvair, and SpinTek. They tested these samples in a static test cell with feed slurries containing monosodium titanate and simulated sludge

Technical note concerning the use of cellulose ester filtering membranes in the determination of plutonium in urine

International Nuclear Information System (INIS)

Harduin, J.C.; Montels, P.

1968-01-01

During the last stage of the determination of plutonium in biological media, cellulose ester filtering membranes are used for collecting, with the help of a special device, the very fine precipitate resulting from the co-precipitation of plutonium and lanthanum fluorides. The membranes are then dried, and stuck on to flat watch-glasses for a α counting. A method is then given for purifying the lanthanum so as to keep the background noise during counting as low as possible. (author) [fr

Activated sludge filterability improvement by nitrifying bacteria abundance regulation in an adsorption membrane bioreactor (Ad-MBR).

Science.gov (United States)

Sun, Fei-Yun; Lv, Xiao-Mei; Li, Ji; Peng, Zhong-Yi; Li, Pu; Shao, Ming-Fei

2014-10-01

Autotrophic nitrifying bacteria have its intrinsic properties including low EPS production, dense colonial structure and slow-growth rate, favoring the sludge filterability improvement. An adsorption-MBR (Ad-MBR) was developed to enrich nitrifier abundance in the MBR chamber by inlet C/N regulation, and its possible positive effect on sludge filterability and underlying mechanisms were investigated. By DNA extraction, PCR amplification and Illumina high-throughput pyrosequencing, the abundance of nitrifying bacteria was accurately quantified. More than 8.29% nitrifier abundance was achieved in Ad-MBR sludge, which was above three times of that in conventional MBR. Regulated C/N ratio and thereafter nitrifier abundance enrichment improved sludge filterability by altering sludge mixture and its supernatant properties, reflected by a good sludge settleability, a low supernatant viscosity and turbidity, a low supernatant organic substances concentration, and a small amount of strong hydrophobic fractional components, thus to profoundly improve sludge filterability and decelerate membrane fouling. Copyright © 2014 Elsevier Ltd. All rights reserved.

Radiation effects in polycarbonate capacitors

Directory of Open Access Journals (Sweden)

Vujisić Miloš

2009-01-01

Full Text Available The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.

Scratch resistance of a polycarbonate + organoclay nanohybrid

Directory of Open Access Journals (Sweden)

2009-10-01

Full Text Available A polycarbonate-based nanohybrid has been created containing 1 wt% of Bentone 2010, an organically modified montmorillonite. A micro-section on the nanohybrid obtained using focused ion beam (FIB and field emission scanning electron microscopy (FESEM was employed to observe the orientation of the nanoclay inside a polycarbonate (PC matrix in the cross-section FIB-milled face. A micro-scratch tester was used to measure the scratch resistance in terms of residual (healing depth Rh under progressive load and in sliding wear. Effects of the number of scratches, normal load and scratch velocity have been evaluated as a function of nanoclay orientation. In sliding wear (multiple scratching along the same groove, our nanohybrid reaches residual depth values that remain constant after a certain number of scratches, a manifestation of strain hardening. The number of scratches to induce strain hardening decreases as the normal applied load increases. SEM was used to characterize deformation and wear mechanisms that operate on contacts and the results related to the wear data.

Air effect on polycarbonate radiolysis

International Nuclear Information System (INIS)

Terence, Mauro C.; Araujo, Elmo S.; Guedes, Selma M.L.

1995-01-01

The formation and decay of radicals in the radiolysis of new type of polycarbonate (G scission = 0,73) was investigated by electron spin resonance spectroscopy in the presence and absence of air at room temperature. The air does not interfere in the formation of radicals because they are formed as consequence of direct interaction of radiation. But the air interferes in their decays. During the irradiation the air reacts with all isopropyl radicals and with 2/3 of phenoxy + phenyl radicals. (author). 5 refs., 3 figs

Water heating solar system using collector with polycarbonate absorber surface

Energy Technology Data Exchange (ETDEWEB)

Souza, Luiz Guilherme Meira de; Sodre, Dilton; Cavalcanti, Eduardo Jose Cidade; Souza, Luiz Guilherme Vieira Meira de; Mendes, Jose Ubiragi de Lima [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mails: lguilherme@dem.ufrn.br, diltonsodre@ifba.edu.br, ubiragi@ct.ufrn.br

2010-07-01

It is presented s solar collector to be used in a heating water for bath system, whose main characteristics are low cost and easy fabrication and assembly processes. The collector absorber surface consists of a polycarbonate plate with an area of 1.5 m{sup 2}. The water inlet and outlet are made of PVC 50mm, and were coupled to a 6mm thick polycarbonate plate using fiberglass resin. A 200 liters thermal reservoir will be used. This reservoir is also alternative. The absorber heating system works under thermo-siphon regimen. Thermal parameters will be evaluated to prove the feasibility of the studied solar heating system to obtain bath water for a four people family. (author)

Postpolymerization Modifications of Alkene-Functional Polycarbonates for the Development of Advanced Materials Biomaterials.

Science.gov (United States)

Thomas, Anthony W; Dove, Andrew P

2016-12-01

Functional aliphatic polycarbonates have attracted significant attention as materials for use as biomedical polymers in recent years. The incorporation of pendent functionality offers a facile method of modifying materials postpolymerization, thus enabling functionalities not compatible with ring-opening polymerization (ROP) to be introduced into the polymer. In particular, polycarbonates bearing alkene-terminated functional groups have generated considerable interest as a result of their ease of synthesis, and the wide range of materials that can be obtained by performing simple postpolymerization modifications on this functionality, for example, through radical thiol-ene addition, Michael addition, and epoxidation reactions. This review presents an in-depth appraisal of the methods used to modify alkene-functional polycarbonates postpolymerization, and the diversity of practical applications for which these materials and their derivatives have been used. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly Conductive Multifunctional Graphene Polycarbonate Nanocomposites

Science.gov (United States)

Yoonessi, Mitra; Gaier, James R.

2010-01-01

Graphene nanosheet bisphenol A polycarbonate nanocomposites (0.027 2.2 vol %) prepared by both emulsion mixing and solution blending methods, followed by compression molding at 287 C, exhibited dc electrical percolation threshold of approx.0.14 and approx.0.38 vol %, respectively. The conductivities of 2.2 vol % graphene nanocomposites were 0.512 and 0.226 S/cm for emulsion and solution mixing. The 1.1 and 2.2 vol % graphene nanocomposites exhibited frequency-independent behavior. Inherent conductivity, extremely high aspect ratio, and nanostructure directed assembly of the graphene using PC nanospheres are the main factors for excellent electrical properties of the nanocomposites. Dynamic tensile moduli of nanocomposites increased with increasing graphene in the nanocomposite. The glass transition temperatures were decreased with increasing graphene for the emulsion series. High-resolution electron microscopy (HR-TEM) and small-angle neutron scattering (SANS) showed isolated graphene with no connectivity path for insulating nanocomposites and connected nanoparticles for the conductive nanocomposites. A stacked disk model was used to obtain the average particle radius, average number of graphene layers per stack, and stack spacing by simulation of the experimental SANS data. Morphology studies indicated the presence of well-dispersed graphene and small graphene stacking with infusion of polycarbonate within the stacks.

Novel polycarbonate-based polyurethane elastomers: composition–property relationship

Czech Academy of Sciences Publication Activity Database

Špírková, Milena; Pavličevic, J.; Strachota, Adam; Poreba, Rafal; Bera, O.; Kaprálková, Ludmila; Baldrian, Josef; Šlouf, Miroslav; Lazić, N.; Budinski-Simendic, J.

2011-01-01

Roč. 47, č. 5 (2011), s. 959-972 ISSN 0014-3057 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane elastomer * polycarbonate diol * montmorillonite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.739, year: 2011

Multifunctional transparent protective coatings on polycarbonates prepared using PECVD

Czech Academy of Sciences Publication Activity Database

Mocanu, V.; Stoica, A.; Kelar, L.; Franta, D.; Bursíková, V.; Mikšová, Romana; Peřina, Vratislav

2012-01-01

Roč. 106, SI5 (2012), s. 1460-1464 ISSN 0009-2770 Institutional support: RVO:61389005 Keywords : multilayered coatings * protective * transparent * polycarbonate Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.453, year: 2012

Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

International Nuclear Information System (INIS)

Souto, E.B.; Campos, L.L.

2006-01-01

The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm 2 of the polycarbonate were irradiated with 5 mSv of fast neutrons ( 241 Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H 2 O, 40% C 2 H 5 OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in the plateau to avoid that small

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites

Directory of Open Access Journals (Sweden)

Claudio Larosa

2017-09-01

Full Text Available A polymer nanocomposite was produced by ultrasonic-assisted dispersion of multiwalled carbon nanotubes (MWCNTs in a polycarbonate matrix using p-xylene and dichloromethane as the solvents. The filler loading was varied from 1 to 3 wt % in order to examine the effect of MWCNTs on the structure and properties of the composites. The nanocomposites were characterized by DSC, DTA, TGA, UV–vis, FTIR and Raman spectroscopy to evaluate the changes induced by the filler in the polymer matrix. UV–vis, FTIR and Raman spectroscopy measurements confirmed the presence of the dispersed phase in the composite films, while TGA and DSC analysis of the nanocomposites revealed enhanced thermal stability and decreased crystallinity, respectively, as compared to the neat polymer. The proposed composites can find application in a number of everyday products where polycarbonate is the base polymer.

Reducing uncertainties associated with filter-based optical measurements of light absorbing carbon particles with chemical information

Science.gov (United States)

Engström, J. E.; Leck, C.

2011-08-01

The presented filter-based optical method for determination of soot (light absorbing carbon or Black Carbon, BC) can be implemented in the field under primitive conditions and at low cost. This enables researchers with small economical means to perform monitoring at remote locations, especially in the Asia where it is much needed. One concern when applying filter-based optical measurements of BC is that they suffer from systematic errors due to the light scattering of non-absorbing particles co-deposited on the filter, such as inorganic salts and mineral dust. In addition to an optical correction of the non-absorbing material this study provides a protocol for correction of light scattering based on the chemical quantification of the material, which is a novelty. A newly designed photometer was implemented to measure light transmission on particle accumulating filters, which includes an additional sensor recording backscattered light. The choice of polycarbonate membrane filters avoided high chemical blank values and reduced errors associated with length of the light path through the filter. Two protocols for corrections were applied to aerosol samples collected at the Maldives Climate Observatory Hanimaadhoo during episodes with either continentally influenced air from the Indian/Arabian subcontinents (winter season) or pristine air from the Southern Indian Ocean (summer monsoon). The two ways of correction (optical and chemical) lowered the particle light absorption of BC by 63 to 61 %, respectively, for data from the Arabian Sea sourced group, resulting in median BC absorption coefficients of 4.2 and 3.5 Mm-1. Corresponding values for the South Indian Ocean data were 69 and 97 % (0.38 and 0.02 Mm-1). A comparison with other studies in the area indicated an overestimation of their BC levels, by up to two orders of magnitude. This raises the necessity for chemical correction protocols on optical filter-based determinations of BC, before even the sign on the

Reducing uncertainties associated with filter-based optical measurements of light absorbing carbon particles with chemical information

Directory of Open Access Journals (Sweden)

J. E. Engström

2011-08-01

Full Text Available The presented filter-based optical method for determination of soot (light absorbing carbon or Black Carbon, BC can be implemented in the field under primitive conditions and at low cost. This enables researchers with small economical means to perform monitoring at remote locations, especially in the Asia where it is much needed.

One concern when applying filter-based optical measurements of BC is that they suffer from systematic errors due to the light scattering of non-absorbing particles co-deposited on the filter, such as inorganic salts and mineral dust. In addition to an optical correction of the non-absorbing material this study provides a protocol for correction of light scattering based on the chemical quantification of the material, which is a novelty. A newly designed photometer was implemented to measure light transmission on particle accumulating filters, which includes an additional sensor recording backscattered light. The choice of polycarbonate membrane filters avoided high chemical blank values and reduced errors associated with length of the light path through the filter.

Two protocols for corrections were applied to aerosol samples collected at the Maldives Climate Observatory Hanimaadhoo during episodes with either continentally influenced air from the Indian/Arabian subcontinents (winter season or pristine air from the Southern Indian Ocean (summer monsoon. The two ways of correction (optical and chemical lowered the particle light absorption of BC by 63 to 61 %, respectively, for data from the Arabian Sea sourced group, resulting in median BC absorption coefficients of 4.2 and 3.5 Mm⁻¹. Corresponding values for the South Indian Ocean data were 69 and 97 % (0.38 and 0.02 Mm⁻¹. A comparison with other studies in the area indicated an overestimation of their BC levels, by up to two orders of magnitude. This raises the necessity for chemical correction protocols on optical filter

Diamond-like carbon films deposited on polycarbonates by plasma-enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Guo, C.T. [Department of Computer and Communication, Diwan College of Management, 72141 Taiwan (China)], E-mail: ctguo@dwu.edu.tw

2008-04-30

Diamond-like carbon films were coated on optical polycarbonate using plasma-enhanced chemical vapor deposition. A mixture of SiH{sub 4} and CH{sub 4}/H{sub 2} gases was utilized to reduce the internal compressive stress of the deposited films. The structure of the DLC films was characterized as a function of film thickness using Raman spectroscopy. The dependence of G peak positions and the intensity ratio of I{sub D}/I{sub G} on the DLC film thicknesses was analyzed in detail. Other studies involving atomic force microscopy, ultraviolet visible spectrometry, and three adhesion tests were conducted. Good transparency in the visible region, and good adhesion between diamond-like carbon films and polycarbonate were demonstrated. One-time recordings before and after a DLC film was coated on compact rewritable disc substrates were analyzed as a case study. The results reveal that the diamond-like carbon film overcoating the optical polycarbonates effectively protects the storage media.

Polycarbonate-based polyurethane elastomers: temperature-dependence of tensile properties

Czech Academy of Sciences Publication Activity Database

Hrdlička, Z.; Kuta, A.; Poreba, Rafal; Špírková, Milena

2014-01-01

Roč. 68, č. 2 (2014), s. 233-238 ISSN 0366-6352 R&D Projects: GA ČR GAP108/10/0195 Institutional support: RVO:61389013 Keywords : polyurethane * elastomer * polycarbonate diol Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.468, year: 2014

The influence of ultrasound on wine and wine materials acidity during clarification process in tubular membrane filters

Directory of Open Access Journals (Sweden)

A. A. Ponedelchenko

2016-01-01

Full Text Available Researches on the experimental ultrasonic installation were carried out, using industrial equipment for bottling liquids and ultrasonic apparatus "Volna-M" UZTA-1/22-OM, for clarification and filtering of table wines by tangential microfiltration using membrane ceramic filtering elements with a pore size of 0.2 micron at a pressure of 0.5-2.0 bar. Membrane ultrafiltration upon application of ultrasound of 30-40 microns amplitude and a frequency of 20 kHz ± 1.65 Hz at high filter performance and work stability changes the quantitative content of the valuable wine components slightly. But much attention to the increase of titratable acidity and pH medium due to possible degradation and esterification intensification of higher acids and alcohols was paid. At the same time more intense and rich aroma and distinct flavor with berry notes appears in wine that along with the physical- and chemical indicators helped to improve organoleptic characteristics and to increase the tasting evaluation of wines. At the same time, the content of phenolic and nitrogen compounds is reduced resulting in wines stability to protein and colloidal opacification. It became possible to refuse multiple regeneration of ceramic filter elements for the  ecovery of their performance, as well as the use of preservatives and antiseptics at a high wines bottling stability. It is shown that the filtration with the dosing of ultrasound in the wine industry allows not only reducing the cost of consumables, equipment and removing some of the traditional processes, but also providing the cold sterilization of wine materials with an increase in their quality.

Low-temperature bonding process for the fabrication of hybrid glass-membrane organ-on-a-chip devices

Science.gov (United States)

Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

2016-10-01

The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organs-on-a-chip," which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass-based devices have long been utilized in the field of microfluidics but the integration of alternative functional elements within multilayered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimized on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650°C) and quartz/fused silica bonding (1050°C) processes, this method maintains the integrity and functionality of the membrane (Tg 150°C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 h, indicating sufficient bond strength for long-term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

Polycarbonate as an Elasto-Plastic Material Model for Simulation of the Microstructure Hot Imprint Process

Directory of Open Access Journals (Sweden)

Rokas Šakalys

2013-08-01

Full Text Available The thermal imprint process of polymer micro-patterning is widely applied in areas such as manufacturing of optical parts, solar energy, bio-mechanical devices and chemical chips. Polycarbonate (PC, as an amorphous polymer, is often used in thermoforming processes because of its good replication characteristics. In order to obtain replicas of the best quality, the imprint parameters (e.g., pressure, temperature, time, etc. must be determined. Therefore finite element model of the hot imprint process of lamellar periodical microstructure into PC has been created using COMSOL Multiphysics. The mathematical model of the hot imprint process includes three steps: heating, imprinting and demolding. The material properties of amorphous PC strongly depend on the imprint temperature and loading pressure. Polycarbonate was modelled as an elasto-plastic material, since it was analyzed below the glass transition temperature. The hot imprint model was solved using the heat transfer and the solid stress-strain application modes with thermal contact problem between the mold and polycarbonate. It was used for the evaluation of temperature and stress distributions in the polycarbonate during the hot imprint process. The quality of the replica, by means of lands filling ratio, was determined as well.

Dielectric properties of polycarbonate coated natural fabric Grewia tilifolia

CSIR Research Space (South Africa)

Ramana, CHVV

2011-12-01

Full Text Available attraction of bio-fiber reinforced composites lie in their low density and high strength. Polymer composites of a polycarbonate coated with natural fabric Grewia tilifolia were studied by means of dielectric properties in the frequency range 100 Hz to 1 MHz...

On-site Determination of Trace Arsenic by Reflection-Absorption Colorimetry of Molybdenum Blue Collected on a Membrane Filter.

Science.gov (United States)

Hasegawa, Yuya; Suzuki, Yasutada; Kawakubo, Susumu

2017-01-01

An on-site determination method for trace arsenic has been developed by collecting it as molybdenum blue (MB) in the presence of tetradecyldimethylbenzylammonium chloride on a mixed cellulose ester membrane filter and by measuring reflection absorbance (RA) of MB on the filter using a laboratory-made palm-top size reflection-absorbance colorimeter with a red light-emitting diode. The value of RA was proportional to the amount of arsenic up to 0.5 μg with a detection limit of 0.01 μg. The proposed method was successfully applied to soil extract and hot-spring water samples.

Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

Energy Technology Data Exchange (ETDEWEB)

Souto, E.B.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, IPEN- CNEN/SP Radiation Metrology Center (CMR) Av. Prof. Lineu Prestes, 2242 CEP: 05508-000 Sao Paulo - SP (Brazil)]. e-mail: ebsouto@ipen.br

2006-07-01

The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm{sup 2} of the polycarbonate were irradiated with 5 mSv of fast neutrons ({sup 241}Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H{sub 2}O, 40% C{sub 2}H{sub 5}OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in

In-situ biogas sparging enhances the performance of an anaerobic membrane bioreactor (AnMBR) with mesh filter in low-strength wastewater treatment.

Science.gov (United States)

Li, Na; Hu, Yi; Lu, Yong-Ze; Zeng, Raymond J; Sheng, Guo-Ping

2016-07-01

In the recent years, anaerobic membrane bioreactor (AnMBR) technology is being considered as a very attractive alternative for wastewater treatment due to the striking advantages such as upgraded effluent quality. However, fouling control is still a problem for the application of AnMBR. This study investigated the performance of an AnMBR using mesh filter as support material to treat low-strength wastewater via in-situ biogas sparging. It was found that mesh AnMBR exhibited high and stable chemical oxygen demand (COD) removal efficiencies with values of 95 ± 5 % and an average methane yield of 0.24 L CH4/g CODremoved. Variation of transmembrane pressure (TMP) during operation indicated that mesh fouling was mitigated by in-situ biogas sparging and the fouling rate was comparable to that of aerobic membrane bioreactor with mesh filter reported in previous researches. The fouling layer formed on the mesh exhibited non-uniform structure; the porosity became larger from bottom layer to top layer. Biogas sparging could not change the composition but make thinner thickness of cake layer, which might be benefit for reducing membrane fouling rate. It was also found that ultrasonic cleaning of fouled mesh was able to remove most foulants on the surface or pores. This study demonstrated that in-situ biogas sparging enhanced the performance of AnMBRs with mesh filter in low-strength wastewater treatment. Apparently, AnMBRs with mesh filter can be used as a promising and sustainable technology for wastewater treatment.

Low-temperature bonded glass-membrane microfluidic device for in vitro organ-on-a-chip cell culture models

Science.gov (United States)

Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

2015-12-01

The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organson- a-chip", which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass based devices have long been utilised in the field of microfluidics but the integration of alternative functional elements within multi-layered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimised on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650 °C) and quartz/fused silica bonding (1050 °C) processes, this method maintains the integrity and functionality of the membrane (Tg 150 °C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 hours, indicating sufficient bond strength for long term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

Caught in a net: Retention efficiency of microplankton ≥ 10 and < 50 μm collected on mesh netting

Science.gov (United States)

Molina, Vanessa; Robbins-Wamsley, Stephanie H.; Riley, Scott C.; First, Matthew R.; Drake, Lisa A.

2018-03-01

Living organisms ≥ 10 μm and loss of organisms that, in turn, may underestimate the concentration of organisms within samples. To address this loss, the retention efficiency (RE) was determined for six filtration approaches using laboratory cultures of microalgae and ambient marine organisms. The approaches employed a membrane filter or mesh nettings of different compositions (nylon, stainless steel, polyester, and polycarbonate), nominal pore sizes (5, 7, and 10 μm), and filtering sequences (e.g., pre-filtering water through a coarse filter). Additionally, in trials with polycarbonate track etched (PCTE) membrane filters, water was amended with particulate material to increase turbidity. Organisms ≥ 10 μm were counted in the material retained on the filter (the filtrand), the material passing through the filter (the filtrate), and the whole water (i.e., unfiltered water). In addition, variable fluorescence fluorometry was used to gauge the relative photochemical yield of phytoplankton-a proximal measurement of the physiological status of phytoplankton-in the size fractions. Further, the mesh types and filters were examined using scanning electron microscopy, which showed irregular openings. The RE of cultured organisms-calculated as the concentration in the filtrand relative to combined concentration in the filtrand and the filtrate-was high for all filtration approaches when laboratory cultures were assessed (> 93%), but RE ranged from 66 to 98% when mixed assemblages of ambient organisms were evaluated. Although PCTE membrane filters had the highest RE (98%), it was not significantly higher than the efficiencies of the 7-μm polyester, Double 7-μm polyester, and Dual 35-μm and 7-μm polyester approaches, but it was significantly higher than the 5-μm nylon and 5-μm stainless steel techniques. This result suggests that PCTE membrane filters perform comparably to 7-μm polyester meshes, so that any of these approaches could be used for concentrating

Fatigue Fracture Behaviors of Transparent Polycarbonate Materials

OpenAIRE

ZHANG Xiao-wen; WU Nan; ZHANG Xuan; MA Li-ting; LI Lei

2017-01-01

The effect of the different stress ratios (R) and annealing treatment on the fatigue properties of the transparent polycarbonate (PC) sheet and the mechanism behind were studied, the fatigue crack propagation (FCP) process and mechanism were analyzed. The results show that after annealing, the residual stress of the PC samples decreases obviously and the fatigue properties are greatly improved. This is because the machining process results in tensile stress in the PC samples, eliminating the ...

Are vacuum-filtrated reduced graphene oxide membranes symmetric?

KAUST Repository

Tang, Bo; Zhang, Lianbin; Li, Renyuan; Wu, Jinbo; Hedhili, Mohamed Neijib; Wang, Peng

2015-01-01

Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

Are vacuum-filtrated reduced graphene oxide membranes symmetric?

KAUST Repository

Tang, Bo

2015-12-02

Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

COMPARISON OF MEMBRANE FILTER, MULTIPLE-FERMENTATION-TUBE, AND PRESENCE-ABSENCE TECHNIQUES FOR DETECTING TOTAL COLIFORMS IN SMALL COMMUNITY WATER SYSTEMS

Science.gov (United States)

Methods for detecting total coliform bacteria in drinking water were compared using 1483 different drinking water samples from 15 small community water systems in Vermont and New Hampshire. The methods included the membrane filter (MF) technique, a ten tube fermentation tube tech...

Carbon nanotube filters

Science.gov (United States)

Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

2004-09-01

Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

Surfactant-controlled etching of ion track nanopores and its practical applications in membrane technology

International Nuclear Information System (INIS)

Apel, P.Yu.; Blonskaya, I.V.; Dmitriev, S.N.; Mamonova, T.I.; Orelovitch, O.L.; Sartowska, B.; Yamauchi, Yu.

2008-01-01

The effect of surfactants on chemical development of ion tracks in polymers has been studied. It has been shown that surface-active agents added to an alkaline etching solution adsorb on the polymer surface at the pore entrances. This reduces the etch rate, which leads to the formation of pores tapered toward the surface. Self-assembly of surfactant molecules at the pore entrance creates a barrier for their penetration into the etched-out nanopores, whereas hydroxide ions diffuse freely. Due to this, the internal pore volume grows faster than the pore surface diameter. The ability to control pore shape is demonstrated with the fabrication of profiled nano- and micropores in polyethylene terephthalate, polycarbonate. Some earlier published data on small track-etched pores in polycarbonate (in particular, the pore diameter vs. etching time curves measured conductometrically) have been revised in light of the above findings. Adding surfactants to chemical etchants makes it possible to optimize the structure of track membranes, thus improving their retention and permeation properties. Asymmetric membranes with thin skin retention layers have been produced and their performance studied

Ceramic hot-gas filter

Science.gov (United States)

Connolly, E.S.; Forsythe, G.D.; Domanski, D.M.; Chambers, J.A.; Rajendran, G.P.

1999-05-11

A ceramic hot-gas candle filter is described having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during back pulse cleaning and is resistant to chemical degradation at high temperatures.

Ceramic hot-gas filter

Science.gov (United States)

Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

1999-01-01

A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

EVALUATION OF ALTERNATIVE FILTER MEDIA FOR THE ROTARY MICROFILTER

Energy Technology Data Exchange (ETDEWEB)

Poirier, M.; Herman, D.; Bhave, R.

2011-09-13

SRS is currently developing and testing several processes to treat high level radioactive liquid waste. These processes include the Integrated Salt Disposition Process (ISDP), the Salt Waste Processing Facility (SWPF), and the Small Column Ion Exchange Process (SCIX). Each of these processes has a solid-liquid separation process that limits its throughput. SRNL researchers identified and tested the rotary microfilter as a technology to increase solid-liquid separation throughput. The testing showed significant improvement in filter flux with the rotary microfilter over the baseline crossflow filter (i.e., 2.5-6.5X during scoping tests, as much as 10X in actual waste tests, and approximately 3X in pilot-scale tests). SRNL received funding from DOE EM-21, and subsequently DOE EM-31 to develop the rotary microfilter for high level radioactive service. The work has included upgrading the rotary microfilter for radioactive service, testing with simulated SRS waste streams, and testing it with simulated Hanford waste streams. While the filtration rate is better than that obtained during testing of crossflow filters, the authors believe the rotary microfilter throughput can be improved by using a better filter membrane. The rotary microfilter membrane is made of stainless steel (Pall PMM050). Previous testing, funded by DOE EM-21, showed that asymmetric filters composed of a ceramic membrane on top of a stainless steel support produced higher filter flux than 100% stainless steel symmetric filters in crossflow filter tests. In that testing, the Pall Accusep and Graver filters produced 13-21% larger filter flux than the baseline 0.1 {micro}m Mott filter. While the improvement in flux is not as dramatic as the improvement of the rotary filter over a crossflow filter, a 13-21% increase could reduce the lifetime of a 30 year process by 4-6 years, with significant cost savings. Subsequent rotary filter testing showed the Pall PMM050 stainless steel filter membrane produced

Polycyanurates and Polycarbonates Based on Eugenol: Alternatives to Thermosetting and Thermoplastic Polymers Based on Bisphenol A

Science.gov (United States)

2014-08-14

to 5a. CONTRACT NUMBER In-House Thermosetting and Thermoplastic Polymers based on Bisphenol A 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Francisco, CA, 14 August 2014. PA#14389 14. ABSTRACT Polycyanurate thermosetting networks, polycarbonate thermoplastics, and homogenous polycarbonate...ON EUGENOL: ALTERNATIVES TO THERMOSETTING AND THERMOPLASTIC POLYMES BASED ON BISPHENOL A 14 August 2014 Andrew J. Guenthner1, Benjamin G. Harvey2

Migration of bisphenol A from polycarbonate plastic of different qualities

DEFF Research Database (Denmark)

Pedersen, Gitte Alsing; Hvilsted, Søren; Petersen, Jens Højslev

to examine the potential correlation between material specific parameters and the release of bisphenol A. It is concluded, from industry information, that only highly pure reagent grade chemicals, including additives, should be used for all polycarbonate grades to reduce photodegradation and hydrothermal...

Phase separation and orientation in EVA/polycarbonate

International Nuclear Information System (INIS)

Martins-Franchetti, S.M.; Nunes, S.P.

1988-01-01

Blends of the polycarbonate of bisphenol-A-(PC) with poly(ethylene-co-vinylacetate) (EVA) were prepared by solution casting in different solvents and various proportions. Their behaviours was examined by diferential scanning calorimetry (DSC), X-ray diffraction and u.v. spectrophotometry. The results obtained show that PC and EVA form partially miscible blends. In some cases, birefringence was observed by optical microscopy indicating the occurrence of polymer orientation in the neighbourhood of the interfaces. (author) [pt

Domain Structures in Nematic Liquid Crystals on a Polycarbonate Surface

Directory of Open Access Journals (Sweden)

Vasily F. Shabanov

2013-08-01

Full Text Available Alignment of nematic liquid crystals on polycarbonate films obtained with the use of solvents with different solvations is studied. Domain structures occurring during the growth on the polymer surface against the background of the initial thread-like or schlieren texture are demonstrated. It is established by optical methods that the domains are stable formations visualizing the polymer surface structures. In nematic droplets, the temperature-induced transition from the domain structure with two extinction bands to the structure with four bands is observed. This transition is shown to be caused by reorientation of the nematic director in the liquid crystal volume from the planar alignment to the homeotropic state with the pronounced radial configuration of nematic molecules on the surface. The observed textures are compared with different combinations of the volume LC orientations and the radial distribution of the director field and the disclination lines at the polycarbonate surface.

Etched ion track polymer membranes for sustained drug delivery

International Nuclear Information System (INIS)

Rao, Vijayalakshmi; Amar, J.V.; Avasthi, D.K.; Narayana Charyulu, R.

2003-01-01

The method of track etching has been successfully used for the production of polymer membranes with capillary pores. In the present paper, micropore membranes have been prepared by swift heavy ion irradiation of polycarbonate (PC). PC films were irradiated with ions of gold, silicon and oxygen of varying energies and fluence. The ion tracks thus obtained were etched chemically for various time intervals to get pores and these etched films were used as membranes for the drug release. Ciprofloxacine hydrochloride was used as model drug for the release studies. The drug content was estimated spectrophotometrically. Pore size and thus the drug release is dependent on the etching conditions, ions used, their energy and fluence. Sustained drug release has been observed in these membranes. The films can be selected for practical utilization by optimizing the irradiation and etching conditions. These films can be used as transdermal patches after medical treatment

Synthesis and Characterization of Polycarbonates by Melt Phase Interchange Reactions of Alkylene and Arylene Diacetates with Alkylene and Arylene Diphenyl Dicarbonates

Directory of Open Access Journals (Sweden)

Bassam A. Sweileh

2010-05-01

Full Text Available This work presents a new synthetic approach to aromatic and aliphatic polycarbonates by melt polycondensation of bisphenol A diacetates with alkylene- and arylenediphenyl dicarbonates. The diphenyl dicarbonates were prepared from phenyl chloroformate and the corresponding dihydroxy compounds. The process involved a precondensation step under a slow stream of dry argon with the elimination of phenyl acetate, followed by melt polycondensation at high temperature and under vacuum. The potential of this reaction is demonstrated by the successful synthesis of a series of aromatic-aromatic and aromatic-aliphatic polycarbonates having inherent viscosities from 0.19 to 0.43 dL/g. Thus low to intermediate molecular mass polymers were obtained. The 13C-NMR spectra of the carbon of the carbonate group showed that the formed polycarbonates contain partial random sequence distribution of monomer residues in their chains. The polycarbonates were characterized by inherent viscosity, FTIR, 1H-NMR and 13C-NMR spectroscopy. The glass transition temperatures, measured by DSC, of the polycarbonates were in the range 13–108 ºC. The thermogravimetric curves of showed that these polymers have good thermal stability up to 250 ºC. The present approach may open the door for novel polycarbonates containing other organic functional groups.

Semiconductor cleaning liquid delivery system and its filter; Handotaiyo seijo yakueki kyokyu system to filter

Energy Technology Data Exchange (ETDEWEB)

Saito, T. [Kanto Chemical Co. Inc., Tokyo (Japan); Hayama, H.; Sakka, T. [Nitto Denko Corp., Osaka (Japan)

1994-11-30

Most of chemicals used for producing semiconductors are supplied automatically by a chemical delivery system to production devices. This paper explains the current status and the trends of the system. This system supplies the chemicals in the order of a tank lorry, a storage tank, a supply tank, a filter and a production device, and the transfer is performed receiving a supply signal from the supply tank and the production device. The transfer may be done through a dilution equipment. Filters currently used have membrane pore sizes of 0.2 to 0.1 microns as prefilters, and 0.1 to 0.05 microns as final filters. Chemicals used are diverse and can be divided into acid-, alkaline-, and solvent-based groups. Fluorine resin filters are used for acid- and alkaline-resistant applications, and SUS/fluorine resin filters for solvent-resistant applications. Use of large-sized filters of element construction with a membrane area of 1 m{sup 2} class is increasing recently in addition to selection from a performance viewpoint, including particle removing performance. 9 figs., 7 tabs.

Radiation effects in the polycarbonate of bisphenol-A. Thermoluminescence electron spin resonance and charged particle track studies

International Nuclear Information System (INIS)

Edmonds, E.A.

1978-09-01

A detailed investigation is presented of the thermoluminescence observable above room temperature from the polycarbonate of bisphenol-A after its exposure to different radiations. A correlation study is described by which features of the complex thermoluminescence glow curve from a commercial grade of the polycarbonate of bisphenol-A are related to the etchability of charged particle damage trails and the radiogenic ESR signal. A model is presented whereby the etchability of charged particle damage trails is associated with chain scission caused by the high local dose of radiation in the vicinity of the trajectories of charged particles. Methods by which activation constants controlling the thermoluminescence glow curve can be evaluated are discussed and results are presented. It is concluded that glow peaks associated with the ESR signal or enhanced etchability are related to small-scale motions in the molecular matrix of the polycarbonate of bisphenol-A. These motions are thermally activated in accord with the simple Boltzmann relation usually incorporated into theories of thermoluminescence. Another component glow peak of the thermoluminescence glow curve is shown to be associated with the glass-rubber transition in the polycarbonate of bisphenol-A. Different features of the thermoluminescence glow curve can be related to relaxations of the polymer matrix and decomposition of the matrix. It is confirmed that the dominant bulk effect of radiation in the polycarbonate of bisphenol-A exposed to large doses of radiation is chain scission. (author)

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 5 - Mesophase characterization of side-chain liquid crystalline polycarbonates with tails of different lengths

NARCIS (Netherlands)

Jansen, J.C.; Addink, R.; Nijenhuis, K.T.; Mijs, W.J.

1999-01-01

The mesomorphic properties and thermal stability of side-chain LC polycarbonates with alkoxyphenyl benzoate side groups having a short spacer and alkoxy tails ranging from 1 to 8 carbon atoms were studied by DSC, X-ray diffraction and polarized light optical microscopy. All polymers have a smectic A

An assessment of filter aids and filter cloths in the dewatering of intermediate level wastes

International Nuclear Information System (INIS)

Knibbs, R.H.; Hudson, B.C.; Blackwell, J.C.W.

1984-12-01

This report considers a range of filter cloths and precoat materials intended for use in dewatering intermediate level radioactive wastes, and their interaction when used on a rotary drum vacuum filter. The report outlines the advantages and disadvantages of various grades and types of precoat and shows that grades with permeabilities in the intermediate range, 3 to 4 x 10 -12 m 2 , give satisfactory filtrate quality together with ease of operation. The work on filter cloths shows that: radiation damage is not a limiting factor as regards operational life for any of the cloths examined; polyester-based cloths are unsuitable due to their poor resistance to alkali attack; polyamide cloths are satisfactory; and stainless steel Dutch weave cloths are satisfactory and have the added advantage of high strength. The report also briefly considers the radiation resistance of two elastomeric membranes used on the 'epidermal' filter and shows that the natural latex rubber membrane is considerably more resistant to radiation than the silicone rubber membrane and has an estimated operational life of at least 1200 hours when dewatering Magnox silo sludge or α-contaminated alumino ferric flocs. (author)

Filtering device for primary coolant circuits in BWR type reactors

International Nuclear Information System (INIS)

Tajima, Fumio; Yamamoto, Tetsuo.

1985-01-01

Purpose: To obtain a filtering device with a large filtering area and requiring less space. Constitution: A condensate inlet for introducing condensates to be filtered of primary coolant circuits, a filtrate exit, a backwash water exit and a bent tube are disposed to a container, and a plurality of hollow thread membrane modules are suspended in the container. The condensates are caused to flow through the condensate inlet, filtered through the hollow thread membrane and then discharged from the filtrate exit. When the filtering treatment is proceeded to some extent, since solid contents captured in the hollow thread membranes are accumulated, a differential pressure is produced between the condensate inlet and the filtrate exit. When the differential pressure reaches a predetermined value, the backwash is conducted to discharge the liquid cleaning wastes through the backwash exit. The bent tube disposed to the container body is used for water and air draining. The hollow thread membranes are formed with porous resin such as of polyethylene. (Kawakami, Y.)

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4 - Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

NARCIS (Netherlands)

Jansen, J.C.; Addink, R.; Nijenhuis, K.T.; Mijs, W.J.

1999-01-01

Side-chain liquid crystalline polycarbonates with alkoxyphenylbenzoate side groups, having a short spacer and tails ranging from 1 to 8 C-atoms, were synthesized. The polymers were prepared by an organo-zinc catalysed copolymerization of carbon dioxide and mesogenic 4-alkoxyphenyl

Interactions of trace metals with hydrogels and filter membranes used in DET and DGT techniques.

Science.gov (United States)

Garmo, Oyvind A; Davison, William; Zhang, Hao

2008-08-01

Equilibrium partitioning of trace metals between bulk solution and hydrogels/filter was studied. Under some conditions, trace metal concentrations were higher in the hydrogels or filter membranes compared to bulk solution (enrichment). In synthetic soft water, enrichment of cationic trace metals in polyacrylamide hydrogels decreased with increasing trace metal concentration. Enrichment was little affected by Ca and Mg in the concentration range typically encountered in natural freshwaters, indicating high affinity but low capacity binding of trace metals to solid structure in polyacrylamide gels. The apparent binding strength decreased in the sequence: Cu > Pb > Ni approximately to Cd approximately to Co and a low concentration of cationic Cu eliminated enrichment of weakly binding trace metal cations. The polyacrylamide gels also had an affinity for fulvic acid and/or its trace metal complexes. Enrichment of cationic Cd in agarose gel and hydrophilic polyethersulfone filter was independent of concentration (10 nM to 5 microM) but decreased with increasing Ca/ Mg concentration and ionic strength, suggesting that it is mainly due to electrostatic interactions. However, Cu and Pb were enriched even after equilibration in seawater, indicating that these metals additionally bind to sites within the agarose gel and filter. Compared to the polyacrylamide gels, agarose gel had a lower affinity for metal-fulvic complexes. Potential biases in measurements made with the diffusive equilibration in thin-films (DET) technique, identified by this work, are discussed.

Interdiffusion of Polycarbonate in Fused Deposition Modeling Welds

Science.gov (United States)

Seppala, Jonathan; Forster, Aaron; Satija, Sushil; Jones, Ronald; Migler, Kalman

2015-03-01

Fused deposition modeling (FDM), a now common and inexpensive additive manufacturing method, produces 3D objects by extruding molten polymer layer-by-layer. Compared to traditional polymer processing methods (injection, vacuum, and blow molding), FDM parts have inferior mechanical properties, surface finish, and dimensional stability. From a polymer processing point of view the polymer-polymer weld between each layer limits the mechanical strength of the final part. Unlike traditional processing methods, where the polymer is uniformly melted and entangled, FDM welds are typically weaker due to the short time available for polymer interdiffusion and entanglement. To emulate the FDM process thin film bilayers of polycarbonate/d-polycarbonate were annealed using scaled times and temperatures accessible in FDM. Shift factors from Time-Temperature Superposition, measured by small amplitude oscillatory shear, were used to calculate reasonable annealing times (min) at temperatures below the actual extrusion temperature. The extent of interdiffusion was then measured using neutron reflectivity. Analogous specimens were prepared to characterize the mechanical properties. FDM build parameters were then related to interdiffusion between welded layers and mechanical properties. Understating the relationship between build parameters, interdiffusion, and mechanical strength will allow FDM users to print stronger parts in an intelligent manner rather than using trial-and-error and build parameter lock-in.

Dispersion of gold nanoclusters in TMBPA-polycarbonate by a combination of thermal embedding and vapour-induced crystallization

International Nuclear Information System (INIS)

Kruse, J; Dolgner, K; Greve, H; Zaporojtchenko, V; Faupel, F

2006-01-01

Gold nanoclusters can be dispersed into the surface of a bisphenol-A polycarbonate film by acetone vapour induced crystallization, an effect which has been demonstrated in a previous publication of our group. Gold nanoclusters were deposited by physical vapour deposition on an amorphous thin film of polycarbonate. After vapour induced crystallization these clusters were detected by depth profiling to be embedded into the surface, with a concentration maximum in a depth of approximately 100 nm. In this work, we replaced the BPA by the modified tetramethyl bisphenol-A polycarbonate, which shows a slower crystallization kinetics. A strong enhancement of the dispersion depth has been achieved by thermal pre-embedding of the clusters into the surface. Surface analysis by means of atomic force microscopy reflects the rearrangement of polymer material in the course of crystallization

Thermogravimetric analysis of reactor-neutrons-irradiated LEXAN polycarbonate film

International Nuclear Information System (INIS)

Kalsi, P.C.

2000-01-01

The effects of reactor-neutrons irradiation on the thermogravimetric (TG) analysis of LEXAN polycarbonate film in air were studied. Irradiation enhances the degradation rate and the effect increases further with increasing neutron fluence. The kinetics of the different steps of degradation were also evaluated from the TG curves. The activation energy values calculated for all the degradation stages decrease on irradiation. (author)

Band-gap tunable dielectric elastomer filter for low frequency noise

Science.gov (United States)

Jia, Kun; Wang, Mian; Lu, Tongqing; Zhang, Jinhua; Wang, Tiejun

2016-05-01

In the last decades, diverse materials and technologies for sound insulation have been widely applied in engineering. However, suppressing the noise radiation at low frequency still remains a challenge. In this work, a novel membrane-type smart filter, consisting of a pre-stretched dielectric elastomer membrane with two compliant electrodes coated on the both sides, is presented to control the low frequency noise. Since the stiffness of membrane dominates its acoustic properties, sound transmission band-gap of the membrane filter can be tuned by adjusting the voltage applied to the membrane. The impedance tube experiments have been carried out to measure the sound transmission loss (STL) of the filters with different electrodes, membrane thickness and pre-stretch conditions. The experimental results show that the center frequency of sound transmission band-gap mainly depends on the stress in the dielectric elastomer, and a large band-gap shift (more than 60 Hz) can be achieved by tuning the voltage applied to the 85 mm diameter VHB4910 specimen with pre-stretch {λ }0=3. Based on the experimental results and the assumption that applied electric field is independent of the membrane behavior, 3D finite element analysis has also been conducted to calculate the membrane stress variation. The sound filter proposed herein may provide a promising facility to control low frequency noise source with tonal characteristics.

Study of the effect of the gamma radiation in polycarbonate

International Nuclear Information System (INIS)

Khoury, H.J.; Araujo, E.S. de; Silveira, S.V. da

1990-01-01

To estimate the radiation effects in the DUROLON polycarbonate, samples were irradiated with 60 Co gamma beam with doses between 0,2KGy and 50KGy. The results obtained shown variations in the yellowed index above 1KGy dose. Their mechanical proprieties are not changed at interval of this doses. (author) [pt

Pemanfaatan Silika Abu Sekam Padi sebagai Bahan Pengisi Rubber Membrane Filter Press untuk Memisahkan Minyak Inti Sawit

OpenAIRE

Nasruddin

2012-01-01

This research was aimed to obtain rubber membrane filter press (RMFP) from natural rubber (NR) as well as synthetic rubber (chloroprene rubber and nytrike butadiene rubber). The research method was done my vulcanizing natural rubber, synthetic rubber, and filler to shape RMFP. Research formulation was done with 8 units of experiments using variations of mixers that have been pre-determined. The examination to the RMFP was done with ASTM test methods that cover parameters such as viscometer mo...

Application of design for six sigma methodology on portable water filter that uses membrane filtration system: A preliminary study

Science.gov (United States)

Fahrul Hassan, Mohd; Jusoh, Suhada; Zaini Yunos, Muhamad; Arifin, A. M. T.; Ismail, A. E.; Rasidi Ibrahim, M.; Zulafif Rahim, M.

2017-09-01

Portable water filter has grown significantly in recent years. The use of water bottles as a water drink stuff using hand pump water filtration unit has been suggested to replace water bottled during outdoor recreational activities and for emergency supplies. However, quality of water still the issue related to contaminated water due to the residual waste plants, bacteria, and so on. Based on these issues, the study was carried out to design a portable water filter that uses membrane filtration system by applying Design for Six Sigma. Design for Six Sigma methodology consists of five stages which is Define, Measure, Analyze, Design and Verify. There were several tools have been used in each stage in order to come out with a specific objective. In the Define stage, questionnaire approach was used to identify the needs of portable water filter in the future from potential users. Next, Quality Function Deployment (QFD) tool was used in the Measure stage to measure the users’ needs into engineering characteristics. Based on the information in the Measure stage, morphological chart and weighted decision matrix tools were used in the Analyze stage. This stage performed several activities including concept generation and selection. Once the selection of the final concept completed, detail drawing was made in the Design stage. Then, prototype was developed in the Verify stage to conduct proof-of-concept testing. The results that obtained from each stage have been reported in this paper. From this study, it can be concluded that the application of Design for Six Sigma in designing a future portable water filter that uses membrane filtration system is a good start in looking for a new alternative concept with a completed supporting document.

Solid-phase assay for the phosphorylation of proteins blotted on nitrocellulose membrane filters

International Nuclear Information System (INIS)

Valtorta, F.; Schiebler, W.; Jahn, R.; Ceccarelli, B.; Greengard, P.

1986-01-01

A new procedure for the phosphorylation and assay of phosphoproteins is described. Proteins are solubilized from tissue samples, separated by polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane filters, and the blotted polypeptides are phyosphorylated with the catalytic subunit of cyclic AMP (adenosine 3':5'-monophosphate)-dependent protein kinase. The method was developed for the assay of dephosphosynapsin I, but it has also proven suitable for the phosphorylation of other proteins. The patterns of phosphorylation of tissue samples phosphorylated using the new method are similar to those obtained using the conventional test tube assay. Once phosphorylated, the adsorbed proteins can be digested with proteases and subjected to phosphopeptide mapping. The phosphorylated blotted proteins can also be analyzed by overlay techniques for the immunological detection of polypeptides

Comparative study of the mechanical properties from different polycarbonates

International Nuclear Information System (INIS)

Terence, M.C.; Miranda, A.; Guedes, S.M.L.; Sciani, V.

1995-01-01

The polycarbonates (PC) with molecular weight 22000 and 27000 g/mol fabricated by Policarbonatos do Brasil S.A., as irradiated by γ rays with doses between 0 and 300 kGy in presence of air at room temperature. The effects in the mechanical properties of PC were investigated using an INSTRON dynamometer. The results showed that both PC have good mechanical stability. (author). 6 refs, 2 figs

Electrical Transport Through Micro Porous Track Etch Membranes of same Porosity

Science.gov (United States)

Garg, Ravish; Kumar, Vijay; Kumar, Dinesh; Chakarvarti, S. K.

2012-12-01

Porosity, pore size and thickness of membrane are vital factors to influence the transport phenomena through micro porous track etch membranes (TEMs) and affect the various applications like separations, drug release, flow control, bio-sensing and cell size detection etc. based on transport process. Therefore, a better understanding of transport mechanism through TEMs is required for new applications in various thrust areas like biomedical devices and packaging of foods and drugs. Transport studies of electrolytic solutions of potassium chloride, through porous polycarbonate TEMS having cylindrical pores of size 0.2 μm and 0.4 μm with same porosity of 15%, have been carried out using an electrochemical cell. In this technique, the etched filter is sandwiched between two compartments of cell in such a way that the TEM acts as a membrane separating the cell into two chambers. The two chambers are then filled with electrolyte solution (KCl in distilled water). The current voltage characteristics have been drawn by stepping the voltage ranging 0 to 10 V using Keithley 2400 Series Source Measurement Unit. The results indicate that rate of ion transport through cylindrical pores although is independent of pore size of TEMs of same porosity but there seems to be effect of TEM aperture size exposed to the electrolyte used in conducting cell on ion transport magnitude. From the experimental studies, a large deviation in the conduction through TEMs was observed when compared with theoretical consideration which led to the need for modification in the applicability of simple Ohm's law to the conduction through TEMs. It is found that ion transport increases with increase in area of aperture of TEM but much lower than the expected theoretically value.

Evaluation of air samplers and filter materials for collection and recovery of airborne norovirus.

Science.gov (United States)

Uhrbrand, K; Koponen, I K; Schultz, A C; Madsen, A M

2018-04-01

The aim of this study was to identify the most efficient sampling method for quantitative PCR-based detection of airborne human norovirus (NoV). A comparative experiment was conducted in an aerosol chamber using aerosolized murine norovirus (MNV) as a surrogate for NoV. Sampling was performed using a nylon (NY) filter in conjunction with four kinds of personal samplers: Gesamtstaubprobenahme sampler (GSP), Triplex-cyclone sampler (TC), 3-piece closed-faced Millipore cassette (3P) and a 2-stage NIOSH cyclone sampler (NIO). In addition, sampling was performed using the GSP sampler with four different filter types: NY, polycarbonate (PC), polytetrafluoroethylene (PTFE) and gelatine (GEL). The sampling efficiency of MNV was significantly influenced by both sampler and filter type. The GSP sampler was found to give significantly (P airborne NoV. The identification of a suitable NoV air sampler is an important step towards studying the association between exposure to airborne NoV and infection. © 2017 The Society for Applied Microbiology.

Gas stream clean-up filter and method for forming same

International Nuclear Information System (INIS)

Mei, J.S.; DeVault, J.; Halow, J.S.

1993-01-01

A gas cleaning filter is formed in-situ within a vessel containing a fluidizable bed of granular material of a relatively large size fraction. A filter membrane provided by a porous metal or ceramic body or such a body supported a perforated screen on one side thereof is coated in-situ with a layer of the granular material from the fluidized bed by serially passing a bed-fluidizing gas stream through the bed of granular material and the membrane. The layer of granular material provides the filtering medium for the combined membrane-granular layer filter. The filter is not blinded by the granular material and provides for the removal of virtually all of the particulates from a process gas stream. The granular material can be at least partially provided by a material capable of chemically reacting with and removing sulfur compounds from the process gas stream. Low level radioactive waste containing organic material may be incinerated in a fluidized bed in communication with the described filter for removing particulates from the gaseous combustion products

Routine detection of calcium-binding proteins following their adsorption to nitrocellulose membrane filters

International Nuclear Information System (INIS)

Hincke, M.T.

1988-01-01

A routine semiquantitative procedure which permits soluble calcium-binding proteins to be detected following their adsorption to nitrocellulose membrane filters by liquid scintillation counting of specifically bound 45 Ca is described. Proteins with high affinity for calcium such as calmodulin and troponin can be detected with a detection threshold of about 2 μg per 400 μl. Modifications to decrease this limit are feasible and are discussed. This technique should allow calcium-binding proteins of unknown function to be assayed during their purification. It was necessary to treat solutions containing 45 Ca with chelex-100 in order to prevent loss of calcium binding which occurred as the decay product (SC 3+ ) accumulated, suggesting that all studies utilizing 45 Ca as a tracer should evaluate possible interference by this ion

The phase structure of novel polycarbonate-based polyurethane-organoclay nanocomposites

Czech Academy of Sciences Publication Activity Database

Pavličević, J.; Sinadinović-Fišer, S.; Špírková, Milena; Budinski-Simendic, J.; Borota, O.; Janković, M.; Knez, Ž.

560/561, 2012 (2012), s. 771-775 ISSN 1022-6680. [2012 Spring International Conference on Material Sciences and Technology (MST-S). Xi'an, 27.05.2012-30.05.2012] R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : polycarbonate-based polyurethane * hydrogen bonds * bentonite Subject RIV: CD - Macromolecular Chemistry

Comparison of quasistatic to impact mechanical properties of multiwall carbon nanotube/polycarbonate composites

Energy Technology Data Exchange (ETDEWEB)

Brühwiler, Paul A.; Barbezat, Michel; Necola, Adly; Kohls, Doug J.; Bunk, Oliver; Schaefer, Dale W.; Pötschke, Petra (PSI); (EMMPA); (UCIN); (Leibniz)

2010-10-22

We report the quasistatic tensile and impact penetration properties (falling dart test) of injection-molded polycarbonate samples, as a function of multiwall carbon nanotube (MWNT) concentration (0.0-2.5%). The MWNT were incorporated by dilution of a commercial MWNT/polycarbonate masterbatch. The stiffness and quasistatic yield strength of the composites increased approximately linearly with MWNT concentration in all measurements. The energy absorbed in fracture was, however, a negative function of the MWNT concentration, and exhibited different dependencies in quasistatic and impact tests. Small-angle x-ray scattering (SAXS) showed that the dispersion of the MWNT was similar at all concentrations. The negative effects on energy absorption are attributed to agglomerates remaining in the samples, which were observed in optical microscopy and SAXS. Overall, there was a good correspondence between static and dynamic energy absorption.

Tracking of Polycarbonate Films using Low-energy Ions Final Report CRADA No. TC-774-94

Energy Technology Data Exchange (ETDEWEB)

Musket, R. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2018-01-24

Ion tracking is performed almost exclusively using ions with energies near or above the maximum in electronic stopping. For the present study, we have examined the results of etching ion tracks created by ions bombarding polycarbonate films with energies corresponding to stopping well below the maximum and just above the anticipated threshold for creating etchable latent tracks. Low-energy neon and argon ions with 18-60 keV /amu and fluences of about 10⁸/cm² were used to examine the limits for producing etchable tracks in polycarbonate films. By concentrating on the early stages of etching (i.e., -20 nm < SEM hole diameter < -100 nm), we can directly relate the energy deposition calculated for the incident ion to the creation of etchable tracks. The experimental results will be discussed with regard to the energy losses of the ions in the polycarbonate films and to the formation of continuous latent tracks through the entire thickness the films. These results have significant implications with respect to the threshold for formation of etchable tracks and to the use of low-energy ions for lithographic applications.

Bonding polycarbonate brackets to ceramic: : Effects of substrate treatment on bond strength

NARCIS (Netherlands)

Özcan, Mutlu; Vallittu, Pekka K.; Peltomäki, Timo; Huysmans, Marie-Charlotte; Kalk, Warner

2004-01-01

This study evaluated the effects of 5 different surface conditioning methods on the bond strength of polycarbonate brackets bonded to ceramic surfaces with resin based cement. Six disc-shaped ceramic specimens (feldspathic porcelain) with glazed surfaces were used for each group. The specimens were

Single-walled carbon nanotube-facilitated dispersion of particulate TiO2 on ZrO2 ceramic membrane filters.

Science.gov (United States)

Yao, Yuan; Li, Gonghu; Gray, Kimberly A; Lueptow, Richard M

2008-07-15

We report that SWCNTs substantially improve the uniformity and coverage of TiO2 coatings on porous ZrO2 ceramic membrane filters. The ZrO2 filters were dip coated with 100 nm anatase TiO2, TiO2/SWCNT composites, a TiO2+SWCNT mixture, and a TiO2/MWCNT composite at pH 3, 5, and 8. Whereas the TiO2+SWCNT mixture and the TiO2/MWCNT composite promote better coverage and less clumping than TiO2 alone, the TiO2/SWCNT composite forms a complete uniform coating without cracking at pH 5 ( approximately 100% coverage). A combination of chemical and electrostatic effects between TiO2 and SWCNTs forming the composite as well as between the composite and the ZrO2 surface explains these observations.

Recycling of engineering plastics from waste electrical and electronic equipments: influence of virgin polycarbonate and impact modifier on the final performance of blends.

Science.gov (United States)

Ramesh, V; Biswal, Manoranjan; Mohanty, Smita; Nayak, Sanjay K

2014-05-01

This study is focused on the recovery and recycling of plastics waste, primarily polycarbonate, poly(acrylonitrile-butadiene-styrene) and high impact polystyrene, from end-of-life waste electrical and electronic equipments. Recycling of used polycarbonate, acrylonitrile-butadiene-styrene, polycarbonate/acrylonitrile-butadiene-styrene and acrylonitrile-butadiene-styrene/high impact polystrene material was carried out using material recycling through a melt blending process. An optimized blend composition was formulated to achieve desired properties from different plastics present in the waste electrical and electronic equipments. The toughness of blended plastics was improved with the addition of 10 wt% of virgin polycarbonate and impact modifier (ethylene-acrylic ester-glycidyl methacrylate). The mechanical, thermal, dynamic-mechanical and morphological properties of recycled blend were investigated. Improved properties of blended plastics indicate better miscibility in the presence of a compatibilizer suitable for high-end application.

Depth sensitivity of Lexan polycarbonate detector

CERN Document Server

Awad, E M

1999-01-01

The dependence of the registration sensitivity of Lexan polycarbonate with depth inside the detector was studied. Samples of Lexan from General Electric were irradiated to two long range ions. These were Ni and Au ions with a projectile energy of 0.3 and 1 GeV/n. Two independent techniques, the track-diameter technique (TDT) and the track profile technique (TPT), were used. The registration sensitivity was measured at depths of 7, 10, 15, 18, 20, 28, 35 and 40 mu m inside the detector. The results of the two techniques show that the detector sensitivity decreases gradually with the depth inside the detector. It reaches 20 % less compared to sensitivity at the surface after 40 mu m have been removed.

Modification of polycarbonate and polypropylene surfaces by argon ion cluster beams

Czech Academy of Sciences Publication Activity Database

Biederman, H.; Slavinská, D.; Boldyreva, H.; Lehmberg, H.; Takaoka, G.; Matsuo, J.; Kinpara, H.; Zemek, Josef

2001-01-01

Roč. 19, č. 6 (2001), s. 2050-2056 ISSN 0734-2101 R&D Projects: GA MŠk ME 177 Institutional research plan: CEZ:AV0Z1010914; CEZ:MSM113200002 Keywords : polycarbonate * polypropylene * surfometer * atomic force microscop * X-ray photoelectron spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.448, year: 2001

Fabrication and Antibacterial Effects of Polycarbonate/Leaf Extract Based Thin Films

Directory of Open Access Journals (Sweden)

R. Mahendran

2016-01-01

Full Text Available We have reported the preparation and antibacterial activities of leaf extract incorporated polycarbonate thin films to improve the antibacterial characteristics of host polycarbonates (PCs. Crude extracts of Azadirachta indica, Psidium guajava, Acalypha indica, Andrographis paniculata, and Ocimum sanctum were prepared by maceration using Dimethylformamide as solvent. The leaf extracts (LE were incorporated into the PC matrix by solution blending method, and the thin films were fabricated by Thermally Induced Phase Separation (TIPS technique. The antibacterial activities of the as-prepared films were evaluated against E. coli and S. aureus by disk diffusion method. The inhibitory effects of the PC/LE films are higher for S. aureus than the E. coli, but pristine PC film did not exhibit any remarkable antibacterial characteristics. Further, the model fruit (Prunus studies revealed that the PC/LE films retained the freshness of the fruits for more than 11 days. This study demonstrates that the PC/LE films have excellent antibacterial activities; thus, the films could be promising candidate for active antibacterial packaging applications.

A Controlled Design of Ripple-Like Polyamide-6 Nanofiber/Nets Membrane for High-Efficiency Air Filter.

Science.gov (United States)

Zhang, Shichao; Liu, Hui; Zuo, Fenglei; Yin, Xia; Yu, Jianyong; Ding, Bin

2017-03-01

The filtration capacity of fibrous media for airborne particles is restricted by their thick diameter, low porosity, and limited frontal area. The ability to solve this problem would have broad technological implications for various air filtration applications; despite many past efforts, it remains a great challenge to achieve. Herein, a facile and scalable strategy to fabricate the ripple-like polyamide-6 nanofiber/nets (PA-6 NF/N) air filter via combining electrospinning/netting technique with receiving substrate design is demonstrated. This proposed approach allows the scaffold filaments to orderly embed into 2D PA-6 nanonets layer with Steiner-tree structures and nanoscale diameter of ≈20 nm, resulting in the ripple-like membrane with extremely small pore size, highly porous structure, and hugely extended frontal surface, by facilely adjusting its pleat span and pleat pitch. These unique structural advantages enable the ripple-like PA-6 NF/N filter to filtrate the ultrafine particles with high removal efficiency of 99.996%, low air resistance of 95 Pa, and robust quality factor of >0.11 Pa -1 ; using its superlight weight of 0.9 g m -2 and physical sieving manner. This approach has the potentialities to give rise to a novel generation of filter media displaying enhanced filtration capacity for various applications thanks to their nanoscale features and designed macrostructures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation for membrane components of water recycling system. Mizu saisei junkan system yoso no tokusei hyoka

Energy Technology Data Exchange (ETDEWEB)

Tanemura, T; Otsubo, K; Oguchi, M [National Aerospace Laboratory, Tokyo (Japan); Ashida, A; Hamano, N; Mitani, K [Hitachi, Ltd., Tokyo (Japan)

1992-04-01

The configuration of water recycling systems with membrane filters was studied to purify waste water discharged from human beings, animals and plants which is a key subsystem for closed ecological life support systems (CELSS) essential to long-term manned space activity. The filter performance test apparatus with three kinds of filters such as pre-filter, reverse osmosis membrane filter and ultra membrane filter was fabricated to conduct long-term cycling high-concentration tests using artificial urine as original waste water. As a result, since every membrane filter offered their nominal performance incompletely in high-concentration tests, it was necessary to add an NaCl removing apparatus to the system as primary treated water should be used for vegetation. It was also required to test the membrane performance preliminarily because the performance such as membrane life was different between various waste waters. 7 refs., 32 figs., 9 tabs.

Experimental study of filter cake formation on different filter media

International Nuclear Information System (INIS)

Saleem, M.

2009-01-01

Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

Nanofluidics : Silicon for the perfect membrane

NARCIS (Netherlands)

van den Berg, Albert; Wessling, Matthias

2007-01-01

Newly developed ultrathin silicon membranes can filter and separate molecules much more effectively than conventional polymer membranes. Many applications, of economic and medical significance, stand to benefit.

Deashing of coal liquids with ceramic membrane microfiltration and diafiltration

Energy Technology Data Exchange (ETDEWEB)

Bishop, B.; Goldsmith, R. [CeraMem Corp., Waltham, MA (United States)

1995-12-31

Removal of mineral matter from liquid hydrocarbons derived from the direct liquefaction of coal is required for product acceptability. Current methods include critical solvent deashing (Rose{sup {reg_sign}} process from Kerr-McGee) and filtration (U.S. Filter leaf filter as used by British Coal). These methods produce ash reject streams containing up to 15% of the liquid hydrocarbon product. Consequently, CeraMem proposed the use of low cost, ceramic crossflow membranes for the filtration of coal liquids bottoms to remove mineral matter and subsequent diafiltration (analogous to cake washing in dead-ended filtration) for the removal of coal liquid from the solids stream. The use of these ceramic crossflow membranes overcomes the limitations of traditional polymeric crossflow membranes by having the ability to operate at elevated temperature and to withstand prolonged exposure to hydrocarbon and solvent media. In addition, CeraMem`s membrane filters are significantly less expensive than competitive ceramic membranes due to their unique construction. With these ceramic membrane filters, it may be possible to reduce the product losses associated with traditional deashing processes at an economically attractive cost. The performance of these ceramic membrane microfilters is discussed.

Polycarbonate-silsesquioxane and polycarbonate-siloxane nanocomposites: Synthesis, characterization, and application in the fabrication of porous inorganic films

Science.gov (United States)

Abdallah, Jassem

Three types of poly(bicycle[2.2.1]heptane carbonate) or poly(norbornane carbonate) or PNC oligomers were synthesized and characterized via spectroscopic methods and elemental analyses to validate their chemical structures. End-group analyses were used to estimate the degree of polymerization of the oligomers via the use of proton nuclear magnetic resonance (1H NMR) results. Random-coil and rigid-rod models were used to estimate the sizes of individual PNC chains based on the degrees of polymerization calculated from NMR data. Due to the small sizes of the PNC chains, dynamic light scattering (DLS) was incapable of measuring the hydrodynamic radii, RH, of individual chains. Attempts at using gel permeation chromatography (GPC) data to estimate the hydrodynamic radii of individual chains consistently provided values that were an order of magnitude smaller than the estimated sizes of individual chains based on random-coil calculations. The thermal properties of PNCs were determined via differential scanning calorimetry (DSC) and thermogravimetric analyses (TGAs). All three types of PNC structures were both thermally-labile and acidolytically-labile, allowing them to be used as sacrificial materials in both direct-write and thermally-processed template systems. TGA data was used to determine the kinetic parameters for the thermolytic decomposition reactions and evolved-gas analysis via mass spectrometry (TGA-MS) was used to validate the mechanisms for polycarbonate thermolysis reactions that have been previously proposed in literature. PNC oligomers were freely-mixed with hydrogen silsesquioxane (HSQ) to form solutions that were spin-coated to form templated films. Ellipsometry and dielectric measurements were used to track the changes in the optical and dielectric properties of templated films and effective medium approximations were used to estimate the level of porosity incorporated within each porous film. Transmission electron microscopy (TEM) showed that the free

Nuclear Track-Etched Pore Membrane Production Using OAEP's Research Reactor

International Nuclear Information System (INIS)

Chittrakarn, Thawat; Bhongsuwan, Tripob; Wanichapichart, Pikul; Nuanuin, Paiboon; Chongkum, Somporn; Khonduangkaew, Areerat; Bordeepong, Sunaree

2003-10-01

Result of this study shows that the OAEP's nuclear research reactor is a good source of both fast and thermal neutrons for pore piercing process on polycarbonate thin film. With our experimental design, the fast neutron provides better results in pore piercing comparing with thermal neutron bombardment. This can be explained that most of the latent tracks that occur by thermal neutron bombardment do not piercing through the thin film. Chemical etching process using NaOH solution with an appropriated time, concentration and temperature was employed to enlarge the latent tracks in the bombarded film by fast neutrons. Fast neutron bombardment with 5, 10 and 20 minutes bombarding time successfully produces the nuclear track membrane. Pore size and pore density of the produced membranes examined by SEM were 0.24-1.01 μm and 4.67 - 245 x 10 6 pore/cm 2 , respectively. Bubble point test showed the maximum pore diameter of the produced membrane ranged between 1.18 - 3.25 μm. Water permeability was studied and compared between the produced and commercial membranes

Separation membrane development

Energy Technology Data Exchange (ETDEWEB)

Lee, M.W. [Savannah River Technology Center, Aiken, SC (United States)

1998-08-01

A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

Fabrication of nanoporous nuclear track membranes

International Nuclear Information System (INIS)

Peng Liangqiang; Wang Shicheng; Ju Xin; Masaru Yoshida; Yasunari Maekawa

2001-01-01

Polyethylene terephthalate (PET) and polycarbonate (PC) films were irradiated by S, Kr and Xe ions and were illuminated with ultraviolet light. The normalized track etch rate for PET and PC films etched in different conditions were measured by conductometric experiments. It is shown that normalized track etch rate can be over 1000 for PET films, 2000 for PC films under optimized condition. TEM photographs of copper nanowires electroplated into nanoporous nuclear track membranes show that the narrowest wire diameter of copper nanowires is 20 nm and that the pore diameter calculated by conductometric experiments is in agreement with the wire diameter measured by TEM when the pore diameter is over 30 nm

Direct transfer of graphene onto flexible substrates

Science.gov (United States)

Martins, Luiz G. P.; Song, Yi; Zeng, Tingying; Dresselhaus, Mildred S.; Kong, Jing; Araujo, Paulo T.

2013-01-01

In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate’s hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene. PMID:24127582

Direct transfer of graphene onto flexible substrates.

Science.gov (United States)

Martins, Luiz G P; Song, Yi; Zeng, Tingying; Dresselhaus, Mildred S; Kong, Jing; Araujo, Paulo T

2013-10-29

In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate's hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene.

Inferring Trial-to-Trial Excitatory and Inhibitory Synaptic Inputs from Membrane Potential using Gaussian Mixture Kalman Filtering

Directory of Open Access Journals (Sweden)

Milad eLankarany

2013-09-01

Full Text Available Time-varying excitatory and inhibitory synaptic inputs govern activity of neurons and process information in the brain. The importance of trial-to-trial fluctuations of synaptic inputs has recently been investigated in neuroscience. Such fluctuations are ignored in the most conventional techniques because they are removed when trials are averaged during linear regression techniques. Here, we propose a novel recursive algorithm based on Gaussian mixture Kalman filtering for estimating time-varying excitatory and inhibitory synaptic inputs from single trials of noisy membrane potential in current clamp recordings. The Kalman filtering is followed by an expectation maximization algorithm to infer the statistical parameters (time-varying mean and variance of the synaptic inputs in a non-parametric manner. As our proposed algorithm is repeated recursively, the inferred parameters of the mixtures are used to initiate the next iteration. Unlike other recent algorithms, our algorithm does not assume an a priori distribution from which the synaptic inputs are generated. Instead, the algorithm recursively estimates such a distribution by fitting a Gaussian mixture model. The performance of the proposed algorithms is compared to a previously proposed PF-based algorithm (Paninski et al., 2012 with several illustrative examples, assuming that the distribution of synaptic input is unknown. If noise is small, the performance of our algorithms is similar to that of the previous one. However, if noise is large, they can significantly outperform the previous proposal. These promising results suggest that our algorithm is a robust and efficient technique for estimating time varying excitatory and inhibitory synaptic conductances from single trials of membrane potential recordings.

Cs2CO3-promoted polycondensation of CO2with diols and dihalides for the synthesis of miscellaneous polycarbonates

KAUST Repository

Chen, Zuliang

2016-07-12

A one-pot protocol for the direct synthesis of polycarbonates through polycondensation of diols, dihalides and CO2 in the presence of Cs2CO3 is described. The conditions were optimized by studying the polycondensation of CO2 with 1,4-phenylenedimethanol and 1,4-dibromobutane as model monomers. Then, diols and dihalides with different spacers between the reactive groups including aliphatic, aromatic and poly(ethylene glycol) were tested under optimal conditions. Miscellaneous polycarbonates exhibiting molar masses in the range of 43 000 g mol-1 (GPC) and conversion higher than 96% could be obtained. The proposed mechanism rules out the possibility of ether linkage formation during polycondensation and accounts for the creation of carbonate linkages in two different ways. The thermal properties of the synthesized polycarbonates were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). © 2016 The Royal Society of Chemistry.

Development of laundry drainage treatment system with ceramic ultra filter

International Nuclear Information System (INIS)

Kanda, Masanori; Kurahasi, Takafumi

1995-01-01

A compact laundry drainage treatment system (UF system hereafter) with a ceramic ultra filter membrane (UF membrane hereafter) has been developed to reduce radioactivity in laundry drainage from nuclear power plants. The UF membrane is made of sintered fine ceramic. The UF membrane has 0.01 μm fine pores, resulting in a durable, heat-resistant, and corrosion-resistant porous ceramic filter medium. A cross-flow system, laundry drainage is filtrated while it flows across the UF membrane, is used as the filtration method. This method creates less caking when compared to other methods. The UF membrane is back washed at regular intervals with permeated water to minimize caking of the filter. The UF membrane and cross-flow system provides long stable filtration. The ceramic UF membrane is strong enough to concentrate suspended solids in laundry drainage up to a weight concentration of 10%. The final concentrated laundry drainage can be treated in an incinerator. The performance of the UF system was checked using radioactive laundry drainage. The decontamination factor of the UF system was 25 or more. The laundry drainage treatment capacity and concentration ratio of the UF system, as well as the service life of the UF membrane were also checked by examination using simulated non-radioactive laundry drainage. Even though laundry drainage was concentrated 1000 times, the UF system showed good permeated water quality and permeated water flux. (author)

Electrical properties and dielectric spectroscopy of Ar{sup +} implanted polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Chawla, Mahak, E-mail: mahak.chawla@gmail.com; Shekhawat, Nidhi; Aggarwal, Sanjeev; Sharma, Annu [Department of Physics, Kurukshetra University, Kurukshetra - 136119 (India); Nair, K. G. M. [Consultant, UGC-DAE Consortium for Scientific Research, Kalpakkam Node, Kokilamedu-603104, Tamilnadu (India)

2015-05-15

The aim of the present paper is to study the effect of argon ion implantation on electrical and dielectric properties of polycarbonate. Specimens were implanted with 130 keV Ar{sup +} ions in the fluence ranging from 1×10{sup 14} to 1×10{sup 16} ions cm{sup −2}. The beam current used was ∼0.40 µA cm{sup −2}. The electrical conduction behaviour of virgin and Ar{sup +} implanted polycarbonate specimens have been studied through current-voltage (I-V characteristic) measurements. It has been observed that after implantation conductivity increases with increasing ion fluence. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. Relaxation processes were studied by Cole-Cole plot of complex permittivity (real part of complex permittivity, ε′ vs. imaginary part of complex permittivity, ε″). The Cole-Cole plots have also been used to determine static dielectric constant (ε{sub s}), optical dielectric constant (ε{sub ∞}), spreading factor (α), average relaxation time (τ{sub 0}) and molecular relaxation time (τ). The dielectric behaviour has been found to be significantly affected due to Ar{sup +} implantation. The possible correlation between this behaviour and the changes induced by the implantation has been discussed.

Polycarbonate Durolon degradation submitted to gamma radiation

International Nuclear Information System (INIS)

Miranda, A.; Sciani, V.

1993-01-01

The Polycarbonate (PC) Durolon, produced by Policarbonatos do Brasil S.A. with molecular weight 27,000 g/mol was irradiated with 60-Co gamma ray source at IPEN-CNEN/SP with doses range between 0.2 to 1,000 kGy in air at 25 C. The results showed that up to 20 kGy no changes in mechanical properties were observed. Above this value, a drop of the elongation to break was observed, reaching 50% drop of its value by 500 kGy. On the other hand, optical tests showed that about 5 kGy some transmittance variations occurred, reaching 3% of its value for a dose of 300 kGy. (author)

Mechanical, thermal and morphological characterization of polycarbonate/oxidized carbon nanofiber composites produced with a lean 2-step manufacturing process.

Science.gov (United States)

Lively, Brooks; Kumar, Sandeep; Tian, Liu; Li, Bin; Zhong, Wei-Hong

2011-05-01

In this study we report the advantages of a 2-step method that incorporates an additional process pre-conditioning step for rapid and precise blending of the constituents prior to the commonly used melt compounding method for preparing polycarbonate/oxidized carbon nanofiber composites. This additional step (equivalent to a manufacturing cell) involves the formation of a highly concentrated solid nano-nectar of polycarbonate/carbon nanofiber composite using a solution mixing process followed by melt mixing with pure polycarbonate. This combined method yields excellent dispersion and improved mechanical and thermal properties as compared to the 1-step melt mixing method. The test results indicated that inclusion of carbon nanofibers into composites via the 2-step method resulted in dramatically reduced ( 48% lower) coefficient of thermal expansion compared to that of pure polycarbonate and 30% lower than that from the 1-step processing, at the same loading of 1.0 wt%. Improvements were also found in dynamic mechanical analysis and flexural mechanical properties. The 2-step approach is more precise and leads to better dispersion, higher quality, consistency, and improved performance in critical application areas. It is also consistent with Lean Manufacturing principles in which manufacturing cells are linked together using less of the key resources and creates a smoother production flow. Therefore, this 2-step process can be more attractive for industry.

Gold nanoparticles and the corresponding filter membrane as chemosensors and adsorbents for dual signal amplification detection and fast removal of mercury(ii).

Science.gov (United States)

Chen, Gaosong; Hai, Jun; Wang, Hao; Liu, Weisheng; Chen, Fengjuan; Wang, Baodui

2017-03-02

Nowadays, the development of a multifunction system for the simultaneous multiple signal amplification detection and fast removal of Hg 2+ remains a major challenge. Herein, we for the first time used gold nanoparticles (Au NPs) and the corresponding filter membrane as chemosensors and adsorbents for dual signal amplification detection and fast removal of Hg 2+ . Such a system was based on the formation of gold amalgam and a gold amalgam-based reaction between rhodamine B (RhB) and NaBH 4 with fluorescence and colorimetric sensing functions. When the gold amalgam catalyzes the reduction of RhB, the red color and orange fluorescence of RhB gradually changed to colorless by switching the amount of Hg 2+ deposited on 13 nm Au NPs. The detection limit of the fluorescence assay and colorimetric assay is 1.16 nM and 2.54 nM for Hg 2+ , respectively. Interestingly, the color and fluorescence of RhB could be recovered when the above colorless reaction solution was exposed to air for about 2 hours. Taking advantage of the above optical phenomenon, a recyclable paper-based sensor has been developed by immobilizing the Au NPs and RhB dye on filter paper and has been successfully used for detection of Hg 2+ in real water samples. In addition, the filter membrane immobilized Au NPs could allow fast removal of mercury ions in Yellow river water and tap water with the removal efficiency close to 99%.

Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane.

Science.gov (United States)

Zheng, Wei-Chao; Xie, Rui; He, Li-Qun; Xi, Yue-Heng; Liu, Ying-Mei; Meng, Zhi-Jun; Wang, Wei; Ju, Xiao-Jie; Chen, Gang; Chu, Liang-Yin

2015-07-01

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer.

Polycarbonate, Mylar and Havar stopping powers for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions

Energy Technology Data Exchange (ETDEWEB)

Alanko, T. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)]. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Laitinen, P.; Matilainen, A.; Raeisaenen, J.; Virtanen, A. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)

2001-12-03

Stopping powers of polycarbonate, Mylar and Havar for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions have been determined by the transmission method in two geometries. The stopping power values were obtained within uncertainty of 2.1-4.5% for the various materials. The present results are compared with the predictions obtained by the most commonly used procedures employed in obtaining stopping powers. These include the Northcliffe and Schilling model, semi-empirical parametrization of Ziegler et al (SRIM2000) with and without the cores and bonds model and the Hubert et al formulation. SRIM2000 values were in good agreement in case of Mylar and Havar, on average within 3% of present results. For polycarbonate the differences were less than 6% on average. The cores and bonds (CAB) model improved the parametrization values slightly. The Northcliffe and Schilling model and the Hubert et al formulation both yielded values within 5% or less for Mylar and polycarbonate. For the Havar the Hubert et al formulation and the present results disagreed by 10% on average. (author)

Surface effect of KrF laser exposure on ECE of alpha particle tracks in polycarbonate polymer

Energy Technology Data Exchange (ETDEWEB)

Parvin, P. [Physics Department, Amirkabir University, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of) and Laser Research Center, Atomic Energy Organization of Iran, AEOI, Tehran (Iran, Islamic Republic of)]. E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu Ali Sina University, Hamadan (Iran, Islamic Republic of); Sheikh, N. [Gamma Irradiation Center, AEOI, Tehran (Iran, Islamic Republic of); Amiri, N. [Physics Department, Emam Hossien University, Tehran (Iran, Islamic Republic of)

2005-11-15

The optical penetration depth for polycarbonate (PC) at 308nm due to XeCl laser is about 450{mu}m while those of KrF (248nm) and ArF (193nm) lasers become noticeably shorter to 1{mu}m and 20nm, respectively, to show the strong superficial absorption at shorter UV wavelengths. On the other hand, KrF laser exposure on polycarbonate, at doses above 6J/cm{sup 2}, creates the surface crosslinking. In spite of several reliable methods available, such as 'hot set' and 'gel content', to determine the bulk crosslinking, there are a few consistent techniques to evaluate the surface crosslinking effect quantitatively. It includes hardening measurements using nanoindenter or AFM (atomic force microscopy). In this work, we present a technique for the measurement of superficial crosslinking, based on electrochemical etching of alpha irradiated polycarbonate accordingly. The mean diameter of the developed tracks nonlinearly decreases for KrF laser treatment at higher doses. The relative shrinkage of track diameters due to UV exposure before alpha irradiation, comparing to those without UV pre-radiation, indicates that UV laser makes the polymer surface hardened. The variation of mean track diameters can be strongly used to quantify the surface crosslinking.

Surface effect of KrF laser exposure on ECE of alpha particle tracks in polycarbonate polymer

International Nuclear Information System (INIS)

Parvin, P.; Jaleh, B.; Sheikh, N.; Amiri, N.

2005-01-01

The optical penetration depth for polycarbonate (PC) at 308nm due to XeCl laser is about 450μm while those of KrF (248nm) and ArF (193nm) lasers become noticeably shorter to 1μm and 20nm, respectively, to show the strong superficial absorption at shorter UV wavelengths. On the other hand, KrF laser exposure on polycarbonate, at doses above 6J/cm 2 , creates the surface crosslinking. In spite of several reliable methods available, such as 'hot set' and 'gel content', to determine the bulk crosslinking, there are a few consistent techniques to evaluate the surface crosslinking effect quantitatively. It includes hardening measurements using nanoindenter or AFM (atomic force microscopy). In this work, we present a technique for the measurement of superficial crosslinking, based on electrochemical etching of alpha irradiated polycarbonate accordingly. The mean diameter of the developed tracks nonlinearly decreases for KrF laser treatment at higher doses. The relative shrinkage of track diameters due to UV exposure before alpha irradiation, comparing to those without UV pre-radiation, indicates that UV laser makes the polymer surface hardened. The variation of mean track diameters can be strongly used to quantify the surface crosslinking

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of polycarbonate and plastic waste to recover monomers

Science.gov (United States)

Evans, R.J.; Chum, H.L.

1994-06-14

A process is described using fast pyrolysis to convert a plastic waste feed stream containing polycarbonate and ABS to high value monomeric constituents prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of a given polymer to its high value monomeric constituents prior to a temperature range that causes pyrolysis of other plastic components; selecting an acid or base catalysts and an oxide or carbonate support for treating the feed stream to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of the high value monomeric constituents of polycarbonate and ABS in the first temperature program range; differentially heating the feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituents prior to pyrolysis or other plastic components; separating the high value monomeric constituents from the polycarbonate to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at the second higher temperature program range to cause pyrolysis of different high value monomeric constituents; and separating the different high value monomeric constituents. 68 figs.

Controlled catalystic and thermal sequential pyrolysis and hydrolysis of polycarbonate and plastic waste to recover monomers

Science.gov (United States)

Evans, Robert J.; Chum, Helena L.

1994-01-01

A process of using fast pyrolysis to convert a plastic waste feed stream containing polycarbonate and ABS to high value monomeric constituents prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of a given polymer to its high value monomeric constituents prior to a temperature range that causes pyrolysis of other plastic components; selecting an acid or base catalysts and an oxide or carbonate support for treating the feed stream to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of the high value monomeric constituents of polycarbonate and ABS in the first temperature program range; differentially heating the feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituents prior to pyrolysis or other plastic components; separating the high value monomeric constituents from the polycarbonate to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at the second higher temperature program range to cause pyrolysis of different high value monomeric constituents; and separating the different high value monomeric constituents.

Standard specification for architectural flat glass clad polycarbonate

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This specification covers the quality requirements for cut sizes of glass clad polycarbonate (GCP) for use in buildings as security, detention, hurricane/cyclic wind-resistant, and blast and ballistic-resistant glazing applications. 1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Electrochemical properties of amorphous WO3 coatings grown on polycarbonate by aerosol-assisted CVD

International Nuclear Information System (INIS)

Vernardou, D.; Drosos, H.; Spanakis, E.; Koudoumas, E.; Katsarakis, N.; Pemble, M.E.

2012-01-01

Highlights: ► Tungsten oxide is aerosol assisted chemically vapor deposited on polycarbonate. ► Their properties are dependent on the Ar:O 2 ratio during deposition. ► The porous structure enhances their electrochemical performance. - Abstract: Tungsten oxide coatings are chemically vapor deposited on polycarbonate via aerosol assisted at 125 °C. The effect of the Ar:O 2 ratio on the structural, morphological and electrochemical properties of the samples is investigated. The coating grown using Ar:O 2 ratio of 50:50, exhibits the best electrochemical activity and the fastest colouration-bleaching response. At the same time it offers a high specific capacitance that does not degrade upon at least 1000 successive charging–discharging cycles as studied by voltammetry in a solution of 1 M LiClO 4 . The importance of morphology towards the enhancement of the electrochromic behaviour of the coatings is discussed.

The impact of chlorhexidine mouth rinse on the bond strength of polycarbonate orthodontic brackets.

Science.gov (United States)

Hussein, Farouk Ahmed; Hashem, Mohammed Ibrahim; Chalisserry, Elna P; Anil, Sukumaran

2014-11-01

The purpose of the current in-vivo study was to assess the effect of using 0.12% chlorhexidine (CHX) mouth rinse, before bonding, on shear bond strength of polycarbonate brackets bonded with composite adhesive. Eighteen orthodontic patients with a mean age 21.41 ± 1.2 years, who were scheduled to have 2 or more first premolars extracted, were included in this study. Patients were referred for an oral prophylaxis program which included, in part, the use of a mouth rinse. Patients were divided into 2 groups, a test group of 9 patients who used 0.12% CHX gluconate mouth rinse twice daily and a control group of 9 patients who used a mouth rinse without CHX, but with same color. After 1 week, polycarbonate brackets were bonded to first premolars with Transbond XT composite adhesive. Premolars were extracted after 28 days and tested for shear bond strength on a universal testing machine. Student's t-test was used to compare shear bond strengths of both groups. No statistically significant difference was found in bond strengths' values between both groups. The test group (with CHX) has mean shear bond strength of 14.21 ± 2.42 MPa whereas the control group (without CHX) revealed a mean strength of 14.52 ± 2.31 MPa. The use of 0.12% CHX mouth rinse, for one week before bonding, did not affect the shear bond strength of polycarbonate brackets bonded with Transbond composite. Furthermore, these brackets showed clinically acceptable bond strength.

Simulation of polycarbonate-CNT nanocomposite dosimeter based on electrical characteristics

Energy Technology Data Exchange (ETDEWEB)

Malekie, Shahryar; Ziaie, Farhood; Ataee Naeini, Mehran [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School

2016-12-15

In this research work, the electrical behavior of polycarbonate-carbon nanotube composite, over the radiation absorbed dose under a fixed DC voltage was investigated via finite element method. The predicted electrical percolation threshold value in the composite was validated by experimental results published by other scientists. The absorbed dose value was considered as multiplying of heat capacity and temperature rise of the composite, regarding the calorimetric approach. Results show that this kind of composite can be applied for monitoring and radiation protection utilizations.

Physical-chemical hydrodynamics of the processes of sorption-membrane technology of LRW treatment

International Nuclear Information System (INIS)

Alexander D Efanov; Pyotr N Martynov; Yuri D Boltoev; Ivan V Yagodkin; Nataliya G Bogdanovich; Sergey S Skvortsov; Alexander R Sokolovsky; Elena V Ignatova; Gennady V Grigoriev; Vitaly V Grigorov

2005-01-01

Full text of publication follows: Liquid radioactive NPP waste is generated, when radioactive water is collected and mixed from various routine and non-routine process measures being performed in accordance with the operating regulations of reactor units with water coolant. The main sources of LRW are the primary loop water coolant, deactivation, regeneration and rinse waters, waste laundry and showers water producing the initial averaged LRW as well as spent fuel element cooling pond water and water of biological protection tanks. LRW handling can be substantially advanced, in particular, through development and introduction of the non-conventional sorption-membrane technology of NPP LRW treatment, being developed at SSC RF IPPE. This technology makes use of natural inorganic sorbents (tripolite, zeolite, ion-exchange materials) and filtering nano-structured metallic and ceramic membranes (titanium, zirconium, chromium and other or their oxides, carbides and nitrides). The efficiency of the sorption membrane technology is associated just with the investigation of the physical-chemical processes of sorption, coagulation and sedimentation under the conditions of forced and free convection occurring in LRW. Besides, it is necessary to take into consideration that the hydrodynamics of the flows of LRW being decontaminated by membrane filtration depends on the structure and composition of the porous composition pare 'nano-structured membrane-substrate'. Neglecting these peculiarities can result in drastic reduction of the time of stable LRW filtration, reduction of the operability resource of filtration systems or in quick mechanical destruction of porous materials. The paper presents the investigation results on: -the effect of the convection flows being generated by air bubbling or LRW stirring by agitator on the static sorption conditions (sorption time, medium pH, sorbent dispersity, sorbent concentration in liquid medium) and on the efficiency of extraction by

Aliphatic polycarbonate-based polyurethane elastomers and nanocomposites. II. Mechanical, thermal, and gas transport properties

Czech Academy of Sciences Publication Activity Database

Poreba, Rafal; Špírková, Milena; Brožová, Libuše; Lazić, N.; Pavličevič, Jelena; Strachota, Adam

2013-01-01

Roč. 127, č. 1 (2013), s. 329-341 ISSN 0021-8995 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane elastomer * nanocomposite * polycarbonate diol Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.640, year: 2013

Medium chain glycerides of coconut oil for microwave-enhanced conversion of polycarbonate into polyols

Czech Academy of Sciences Publication Activity Database

Beneš, Hynek; Paruzel, Aleksandra; Trhlíková, Olga; Paruzel, Bartosz

2017-01-01

Roč. 86, January (2017), s. 173-187 ISSN 0014-3057 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : medium chain triglycerides * coconut oil * polycarbonate Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.531, year: 2016

Design and development of wide energy neutron REM equivalent spectrometer-dosimeters based on polycarbonates and Cr-39

International Nuclear Information System (INIS)

Faermann, S.

1985-03-01

This work describes a system composed of a Rem response personnel neutron dosemeter, based on boron radiators and a polycarbonate track detector, for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter. A new passive miniature fast neutron spectrometer-dosimeter is also described. The device is based on the detection of proton tracks by electrochemical etching of CR-39 foils covered with thin polyethylene layers of different thicknesses. By means of this device it is possible to assess the fast neutron energy spectrum in 10 energy intervals in the energy range 0.5-15 MeV. Dose equivalents can be determined in the dose equivalent range 20 mRem to 8 Rem, approximately (author)

Directed Hierarchical Patterning of Polycarbonate Bisphenol A Glass Surface along Predictable Sites

Directory of Open Access Journals (Sweden)

Mazen Khaled

2015-01-01

Full Text Available This paper reports a new approach in designing textured and hierarchical surfaces on polycarbonate bisphenol A type glass to improve hydrophobicity and dust repellent application for solar panels. Solvent- and vapor-induced crystallization of thermoplastic glass polycarbonate bisphenol A (PC is carried out to create hierarchically structured surfaces. In this approach dichloromethane (DCM and acetone are used in sequence. Samples are initially immersed in DCM liquid to generate nanopores, followed by exposing to acetone vapor resulting in the generation of hierarchical structure along the interporous sites. The effects of exposure time on the size, density, and distance of the generated spherules and gaps are studied and correlated with the optical transmittance and contact angle measurements at the surface. At optimized exposure time a contact angle of 98° was achieved with 80% optical transmittance. To further increase the hydrophobicity while maintaining optical properties, the hierarchical surfaces were coated with a transparent composite of tetraethyl orthosilicate as precursor and hexamethyldisilazane as silylation agent resulting in an average contact angle of 135.8° and transmittance of around 70%. FTIR and AFM characterization techniques are employed to study the composition and morphology of the generated surfaces.

Field testing of polymeric mesh and ash-based ceramic membranes ...

African Journals Online (AJOL)

This paper presents the initial findings of field testing of 2 low-cost membrane filters, viz. 30 ìm polymeric mesh and 2–6 ìm macroporous waste-ash based ceramic filter, in a submerged membrane bioreactor (MBR) employing batch anoxic and aerobic conditions. The influent was raw wastewater from a residential complex ...

The spark counting of etched fission-fragment tracks in polycarbonate for a personal neutron dosimetry system

International Nuclear Information System (INIS)

Harrison, K.G.; Hancock, I.B.; Holt, P.D.; Wylie, J.W.

1977-10-01

A new type of personal neutron dosimeter, in which neutron-induced fissions in a thin 237 Np foil are detected by a polycarbonate track-detector, is under development at Harwell for use in a nuclear-fuel reprocessing plant. As part of the development programme, an experimental dosimeter, etching facility and spark counter have been used to study the spark-counting method for counting fission-fragment tracks in polycarbonate. Emphasis has been placed on developing operating procedures for the counter consistent with good overall reproducibility. Existing methods for the optimizing and testing of spark counters is briefly reviewed and a practical operational testing procedure is devised. The optimized system is found to be relatively foolproof in operation and gives good results in unskilled use as well as under carefully-controlled laboratory conditions. (author)

Cesium removal from the fuel storage water at the Savannah River Site R-Building Disassembly Basin using 3M Empore reg-sign-membrane filter technology

International Nuclear Information System (INIS)

Oji, L.N.; Thompson, M.C.; Peterson, K.; May, C.; Kafka, T.M.

1998-01-01

This report describes results from a seven-day demonstration of the use of 3M Empore membrane filter loaded with ion exchange material (potassium cobalt hexacynoferrate (CoHex)) for cesium uptake from the R-Disassembly Basin at the Savannah River Site. The goal of the demonstration was to evaluate the ability of the Process Absorber Development unit (PADU), a water pre-filtration /CoHex configuration on a skid, to remove cesium from R-Disassembly Basin at a linear processing flow rate of 22.7 liters per minute (1,195.8 liters/minute/m 2 or 29.35 gallons/minute/ft 2 ). Over 210,000 liters (> 55,500 gallons) of R-Disassembly Basin water was processed through the PADU without a cesium breakthrough, that is, the effluent after treatment with CoHex, contained less than detectable amounts of radioactive cesium. Some of the observed advantages of the Empore membrane filter technology over conventional packed column ion exchange systems includes rapid flow rates without channeling effects, low volume secondary waste and fast extraction or rapid kinetics per unit of flow

Coupling Metallic Nanostructures to Thermally Responsive Polymers Allows the Development of Intelligent Responsive Membranes

Directory of Open Access Journals (Sweden)

J. Rubén Morones-Ramírez

2014-01-01

Full Text Available Development of porous membranes capable of controlling flow or changing their permeability to specific chemical entities, in response to small changes in environmental stimuli, is an area of appealing research, since these membranes present a wide variety of applications. The synthesis of these membranes has been mainly approached through grafting of environmentally responsive polymers to the surface walls of polymeric porous membranes. This synergizes the chemical stability and mechanical strength of the polymer membrane with the fast response times of the bonded polymer chains. Therefore, different composite membranes capable of changing their effective pore size with environmental triggers have been developed. A recent interest has been the development of porous membranes responsive to light, since these can achieve rapid, remote, noninvasive, and localized flow control. This work describes the synthesis pathway to construct intelligent optothermally responsive membranes. The method followed involved the grafting of optothermally responsive polymer-metal nanoparticle nanocomposites to polycarbonate track-etched porous membranes (PCTEPMs. The nanoparticles coupled to the polymer grafts serve as the optothermal energy converters to achieve optical switching of the pores. The results of the paper show that grafting of the polymer and in situ synthesis of the metallic particles can be easily achieved. In addition, the composite membranes allow fast and reversible switching of the pores using both light and heat permitting control of fluid flow.

Chemical Degradation and Stress Cracking of Polycarbonate in DS2.

Science.gov (United States)

1987-09-01

materials are used. For instance, polycarbonate, used widely for air- craft windows, helicopter canopies and transparent armor because of its good impact ...predicting environmental stress cracking of the polymer from solubility con- siderations. The concept has been extended to include a hydrogen bonding...IML Authors . 04 * ! 9 00 9 A S . - . . . q w * . - .* *,.*A CC AX -4-’-~~~~ U--’- ; IO i- A - -C4 = tO -~’ 1 .’ . M0 C , W V E WE1 C ~ 0.0.’un WEC

Determination of HEPA Filter Efficiency With Diocthyl Pthalate Aerosol

International Nuclear Information System (INIS)

Bunawas; Ruslanto, P O; Suhariyono, G

1996-01-01

Ultrafine aerosol filtration by HEPA (High Efficiency Particulate Air) filter has been determinated experimentally, based on the measurement of monodisperse Diocthyl Pthalate (DOP) aerosol concentration before and after passing the test filter. Using this technique, filter efficiency can be determined as a function of aerosol diameter with range from 0.017 to 0.747 um. The average efficiencies for Whatman -41 ; Whatman -42 and Whatman GF/A filters were 56.14 %; 95,74 %; and 99.65 % respectively. Gelman A Fiber Glass and Whatman membrane filter have fulfilled criterion as HEPA filter according to standard of IAEA, because of their minimum effiency of 99.90 %

Chemical separation of plutonium from air filters and preparation of filaments for resonance ionization mass spectroscopy

International Nuclear Information System (INIS)

Eberhardt, K.; Erdmann, N.; Funk, H.; Herrmann, G.; Naehler, A.; Passler, G.; Trautmann, N.; Urban, F.

1995-01-01

Resonance ionization mass spectroscopy (RIMS) is used for the determination of plutonium in environmental samples. A chemical procedure based on an ion-exchange technique for the separation of plutonium from a polycarbonate filter is described. The overall yield is about 60% as determined by α-particle spectroscopy. A technique for the subsequent preparation of samples for RIMS measurements is developed. Plutonium is electrode-posited as hydroxide and covered with a thin metallic layer. While heating such a sandwich filament the plutonium hydroxide is reduced to the metal and an atomic beam is evaporated from the surface, as required for RIMS. copyright American Institute of Physics 1995

A solid phase radio immunoassay on hydrophobic membrane filters: detection of antibodies to gonocal surface antigens

International Nuclear Information System (INIS)

Lambden, P.R.; Watt, P.J.

1978-01-01

A solid phase radioimmunoassay (SPRIA) has been developed for detection of IgG antibodies to gonococcal outer membrane components. Gonococcal antigens was immobilised on a solid support by covalent coupling to CNBr-activated Sepharose in the presence of the detergent Triton X-100. Binding of specific antibody to the Sepharose-antigen complex was detected using radiolabelled Protein A as the antiglobulin. Protein A was labelled by radioacetylation with tritiated acetic anhydride, yielding a product of high specific activity and high stability. No detectable loss of activity was observed over a ten month period. The entire assay was performed on Mitex teflon hydrophobic membrane filters which held the Sepharose beads and aqueous supernatant as a discrete drop of liquid. The supernatants and incubation were easily and rapidly removed from the beads by suction on a specially-designed manifold system. This procedure removed the need for repeated and time-consuming centrifugations. Titres were obtained graphically from double log plots of cpm bound versus antiserum dilution by extrapolation of the straight line to a point corresponding to twice the control level of radioactivity binding. The assay proved to be a very reliable and simple procedure for the detection of IgG antibodies to gonococcal surface antigens. (Auth.)

Integrated antibacterial and antifouling surfaces via cross-linking chitosan-g-eugenol/zwitterionic copolymer on electrospun membranes.

Science.gov (United States)

Li, Zhenguang; Hu, Wenhong; Zhao, Yunhui; Ren, Lixia; Yuan, Xiaoyan

2018-04-27

Integrated antibacterial and antifouling surfaces in favor of avoiding implant-related infections are necessarily required for biomaterials when they contact with the body fluid. In this work, an antibacterial and antifouling membrane was developed via cross-linking chitosan-g-eugenol and the zwitterionic copolymer poly(sulfobetaine methylacrylate-co-2-aminoethyl methacrylate) on the electrospun polycarbonate urethane substrate using genipin as a cross-linker. Antibacterial assays demonstrated that the prepared membranes had efficient antibacterial activity with 92.8 ± 2.5% and 95.2 ± 1.3% growth inhibition rates against Escherichia coli and Staphylococcus aureus, respectively. The investigations on antifouling activity and hemocompatibility of the membranes showed significant resistances to bacterial attachment, non-specific protein adsorption and platelet adhesion, and presented lower hemolytic activity and good anticoagulant activity as well. Moreover, cell culture assays indicated that the prepared membranes exerted no obvious cytotoxicity with more than 80% of relative L929 fibroblast viability. Therefore, the membranes with integrated antibacterial and antifouling properties could be potentially applied in promising indwelling devices. Copyright © 2018 Elsevier B.V. All rights reserved.

Thrombogenicity tests on ar-irradiated polycarbonate foils

Energy Technology Data Exchange (ETDEWEB)

Trindade, Gustavo F.; Rizzutto, Marcia A.; Silva, Tiago F.; Moro, Marcos V.; Added, Nemitala; Tabacniks, Manfredo H., E-mail: g.ferraz@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. de Fisica; Delgado, Adriana O. [Universidade Federal de Sao Carlos (UFSCAR), Sorocaba, SP (Brazil); Cunha, Tatiana F. [Biosintesis P and D do Brasil, Sao Paulo, SP (Brazil); Higa, Olga Z. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia

2013-07-01

Understanding polymer surface properties is extremely important for the most wide range of their applications, from basic coating to the most complex composites and biomaterials. Low energy ion beam irradiation of polymer can improve such surface properties. By modifying its surface biocompatibility, polymers are excellent candidates for biomaterials, due to its malleability and low weight, when compared to metals. In this work, we irradiated 30-μm Bisphenol-A Polycarbonate foils with 23-keV Argon ion beam at six different doses. Aluminium foils were simultaneously irradiated in order to measure the doses by Rutherford Backscattering Spectroscopy. The surface modifications after the argon ion beam irradiation were analyzed by water contact angle measurements and atomic force microscopy. Platelet adhesion tests were used in order to investigate thrombogenicity, showing a growing tendency with the irradiated Argon dose. (author)

Thrombogenicity tests on ar-irradiated polycarbonate foils

International Nuclear Information System (INIS)

Trindade, Gustavo F.; Rizzutto, Marcia A.; Silva, Tiago F.; Moro, Marcos V.; Added, Nemitala; Tabacniks, Manfredo H.; Cunha, Tatiana F.; Higa, Olga Z.

2013-01-01

Understanding polymer surface properties is extremely important for the most wide range of their applications, from basic coating to the most complex composites and biomaterials. Low energy ion beam irradiation of polymer can improve such surface properties. By modifying its surface biocompatibility, polymers are excellent candidates for biomaterials, due to its malleability and low weight, when compared to metals. In this work, we irradiated 30-μm Bisphenol-A Polycarbonate foils with 23-keV Argon ion beam at six different doses. Aluminium foils were simultaneously irradiated in order to measure the doses by Rutherford Backscattering Spectroscopy. The surface modifications after the argon ion beam irradiation were analyzed by water contact angle measurements and atomic force microscopy. Platelet adhesion tests were used in order to investigate thrombogenicity, showing a growing tendency with the irradiated Argon dose. (author)

Performance of water filters towards the removal of selected ...

African Journals Online (AJOL)

Organic matter removal was found to be 47%, 43%, 53%, 43.4% for bio-sand, slow sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% for bone char filter. Furthermore, filters were also assessed in terms of media availability, buying costs, operation, benefits/ effectiveness ...

Efficiency of Polymeric Membrane Graphene Oxide-TiO2 for Removal of Azo Dye

Directory of Open Access Journals (Sweden)

Elahe Dadvar

2017-01-01

Full Text Available Achieving the desired standard of drinking water quality has been one of the concerns across water treatment plants in the developing countries. Processes such as grid chamber, coagulation, sedimentation, clarification, filtration, and disinfection are typically used in water purification plants. Among these methods, unit filtration which employs polymers is one of the new technologies. There have been many studies about the use of semiconductive TiO2 with graphene oxide (GO on the base of different polymeric membranes for the removal of azo dyes, especially methylene blue (MB. Polymeric GO-TiO2 membranes have high photocatalytic, antifouling property and permeate the flux removal of organic pollutants. The aim of this study was to investigate the characteristics of different polymeric membranes such as anionic perfluorinated polymer (Nafion, cellulose acetate, polycarbonate (PC, polysulfone fluoride (PSF, and polyvinylidene fluoride (PVDF. The result of this study showed that the GO-TiO2 membrane can be used in the field of water treatment and will be used for the removal of polycyclic aromatic hydrocarbons (PAHs from wastewater.

Characterization of aerosols containing fissionable elements using solid-state track recorders

International Nuclear Information System (INIS)

Roberts, J.H.; Kafalenos, V.P.; Yule, T.J.

1976-01-01

An aerosol of U 3 O 3 highly enriched in 235 U was generated with a nebulizer from a suspension of U 3 O 8 powder in distilled water. The aerosol was collected on a membrane filter. Polycarbonate plastic, placed in good contact with the filter, was used to record fission tracks when the package was exposed to known fluences of slow neutrons. Fission-track stars associated with individual particles of U 3 O 8 were observed in the plastic. The fission-track distributions were converted to a particle size distribution for the aerosol. For a log normal distribution the geometric mean and standard deviation can be determined with better than 5% accuracy. This method can be applied to plutonium and other transuranic aerosols. (orig.) [de

Enhanced radiometric detection of Mycobacterium paratuberculosis by using filter-concentrated bovine fecal specimens

International Nuclear Information System (INIS)

Collins, M.T.; Kenefick, K.B.; Sockett, D.C.; Lambrecht, R.S.; McDonald, J.; Jorgensen, J.B.

1990-01-01

A commercial radiometric medium, BACTEC 12B, was modified by addition of mycobactin, egg yolk suspension, and antibiotics (vancomycin, amphotericin B, and nalidixic acid). Decontaminated bovine fecal specimens were filter concentrated by using 3-microns-pore-size, 13-mm-diameter polycarbonate filters, and the entire filter was placed into the radiometric broth. Comparison of the radiometric technique with conventional methods on 603 cattle from 9 Mycobacterium paratuberculosis-infected herds found that of 75 positive specimens, the radiometric technique detected 92% while conventional methods detected 60% (P less than 0.0005). Only 3.9% of radiometric cultures were contaminated. To measure the effect of filter concentration of specimens on the detection rate, 5 cattle with minimal and 5 with moderate ileum histopathology were sampled weekly for 3 weeks. M. paratuberculosis was detected in 33.3% of nonfiltered specimens and 76.7% of filtered specimens (P less than 0.005). Detection rates were directly correlated with the severity of disease, and the advantage of specimen concentration was greatest on fecal specimens from cattle with low-grade infections. Detection times were also correlated with infection severity: 13.4 +/- 5.9 days with smear-positive specimens, 27.9 +/- 8.7 days with feces from cows with typical subclinical infections, and 38.7 +/- 3.8 days with fecal specimens from cows with low-grade infections. Use of a cocktail of vancomycin, amphotericin B, and nalidixic acid for selective suppression of nonmycobacterial contaminants was better than the commercial product PANTA (Becton Dickinson Microbiologic Systems, Towson, Md.) only when specimens contained very low numbers of M. paratuberculosis

Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

Directory of Open Access Journals (Sweden)

Rong Zhu

2017-03-01

Full Text Available Abstract: In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate as the catalyst, poly(1,6-hexanediolcarbonate microdiols (PCDL as the soft segment, and the chain extender 1,4-butanediol (BDO and aliphatic 1,6-hexamethylene diisocyanate (HDI as the hard segments. The chemical structures and physical properties of the obtained films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, gel permeation chromatography (GPC, differential scanning calorimeter (DSC, and mechanical property tests. The surface properties and degrees of microphase separation were further analyzed by water droplet contact angle measurements (CA and atomic force microscopy (AFM. The materials exhibited a moderate toxic effect on the tetrazolium (MTT assay and good hemocompatibility through hemolytic tests, indicating a good biocompatibility of the fabricated membranes. The materials could be considered as potential and beneficial suitable materials for tissue engineering, especially in the fields of artificial blood-contacting implants or other biomedical applications.

Chemoselective alternating copolymerization of limonene dioxide and carbon dioxide : a new highly functional aliphatic epoxy polycarbonate

NARCIS (Netherlands)

Li, C.; Sablong, R.J.; Koning, C.E.

The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg) up

Effect of alkali treatment on the morphology and tensile properties of Cordia dichotoma fabric/polycarbonate composites

CSIR Research Space (South Africa)

Jayaramudu, J

2013-05-01

Full Text Available The newly identified natural fabric from the tree of Cordia dichotoma was coated with polycarbonate. Tensile parameters, such as, tensile strength, Young’s modulus, and percentage of elongation at the break of the fabrics were determined using a...

Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

Science.gov (United States)

Bao, Junjie; Shi, Gaojian; Tao, Can; Wang, Chao; Zhu, Chen; Cheng, Liang; Qian, Gang; Chen, Chunhua

2018-06-01

Four kinds of polycarbonate-based polyurethane with 8-14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10-4 S cm-1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g-1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

Electrochemically deposited and etched membranes with precisely sized micropores for biological fluids microfiltration

International Nuclear Information System (INIS)

Hamzah, A A; Zainal Abidin, H E; Yeop Majlis, B; Mohd Nor, M; Ismardi, A; Sugandi, G; Tiong, T Y; Dee, C F; Yunas, J

2013-01-01

This paper presents simple and economical, yet reliable techniques to fabricate a micro-fluidic filter for MEMS lab-on-chip (LoC) applications. The microporous filter is a crucial component in a MEMS LoC system. Microsized components and contaminants in biological fluids are selectively filtered using copper and silicon membranes with precisely controlled microsized pores. Two techniques were explored in microporous membrane fabrication, namely copper electroplating and electrochemical etching (ECE) of silicon. In the first technique, a copper membrane with evenly distributed micropores was fabricated by electroplating the copper layer on the silicon nitride membrane, which was later removed to leave the freestanding microporous membrane structure. The second approach involves the thinning of bulk silicon down to a few micrometers thick using KOH and etching the resulting silicon membrane in 5% HF by ECE to create micropores. Upon testing with nanoparticles of various sizes, it was observed that electroplated copper membrane passes nanoparticles up to 200 nm wide, while porous silicon membrane passes nanoparticles up to 380 nm in size. Due to process compatibility, simplicity, and low-cost fabrication, electroplated copper and porous silicon membranes enable synchronized microfilter fabrication and integration into the MEMS LoC system. (paper)

Dynamic membrane filtration in tangential flow

International Nuclear Information System (INIS)

Anon.

1993-01-01

Oil-containing waste water is produced in many cleaning processes and also on production of compressed air. Dynamic membrane filtration in the tangential flow mode has proved effective in the treatment of these stable emulsions. The possible applications of ceramic membrane filters are illustrated for a variety of examples. (orig.) [de

Influence of asymmetric etching on ion track shapes in polycarbonate

International Nuclear Information System (INIS)

Clochard, M.-C.; Wade, T.L.; Wegrowe, J.-E.; Balanzat, E.

2007-01-01

By combining low-energy ion irradiation with asymmetric etching, conical nanopores of controlled geometry can be etched in polycarbonate (PC). Cone bases vary from 0.5 to 1 μm. Top diameters down to 17 nm are reached. When etching from one side, the pH on the other side (bathed in neutral or acidic buffer) was monitored. Etching temperature ranged from 65 deg. C to 80 deg. C. Pore shape characterization was achieved by electro replication combined with SEM observation. The tip shape depended on whether an acidic buffer was used or not on the stopped side

Technical note concerning the use of cellulose ester filtering membranes in the determination of plutonium in urine; Note technique sur l'utilisation des membranes filtrantes d'esters de cellulose dans le dosage du plutonium dans les urines

Energy Technology Data Exchange (ETDEWEB)

Harduin, J C; Montels, P [Commissariat a l' Energie Atomique, la Hague (France)

1968-07-01

During the last stage of the determination of plutonium in biological media, cellulose ester filtering membranes are used for collecting, with the help of a special device, the very fine precipitate resulting from the co-precipitation of plutonium and lanthanum fluorides. The membranes are then dried, and stuck on to flat watch-glasses for a {alpha} counting. A method is then given for purifying the lanthanum so as to keep the background noise during counting as low as possible. (author) [French] Dans la phase terminale du dosage du plutonium dans les milieux biologiques, on utilise les membranes filtrantes d'esters de cellulose pour recueillir, a l'aide d'un dispositif particulier, le precipite tres tenu resultant de la co-precipitation plutonium-lanthane sous forme de fluorure - Les membranes sont ensuite sechees puis collees sur verre de montre plat avant d'etre passees au compteur alpha. Un mode de purification du lanthane est ensuite donne afin de ne pas augmenter le bruit de fond des appareils de comptage. (auteur)

Morphology Evolution of Polycarbonate-Polystyrene Blends During Compounding

DEFF Research Database (Denmark)

Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib

2001-01-01

The morphology evolution of polycarbonate-polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, re-melt blending in a twin-screw extruder and tri-melt blending in an injection-moulding machine, was investigated using......-empirical model. The results show that the formation of co-continuous morphology strongly depends on blend composition and melt blending method, whereas the model prediction for phase inversion deviates from the experimental values. Further, we found that the initial mechanism of morphology evolution involves...... scanning electron microscopy (SEM) Co examine nine blend compositions. Blends were prepared at compositions where phase inversion was expected to occur according to model predictions. The experimental results were compared to the values of the point of phase inversion calculated with the semi...

A Novel Anti-Pollution Filter for Volatile Agents During Cardiopulmonary Bypass: Preliminary Tests.

Science.gov (United States)

Nigro Neto, Caetano; Landoni, Giovanni; Tardelli, Maria Angela

2017-08-01

Concerns regarding pollution of the operating room by volatile anesthetics and effects on atmospheric ozone depletion exist. Volatile agents commonly are used during cardiopulmonary bypass to provide anesthesia independent of any supposed myocardial protective effects. The authors' aim was to create and to assess the performance of a prototype filter for volatile agents to be connected to the cardiopulmonary bypass circuit to avoid the emission of volatile agents to the operating room, and also to the environment without causing damage to the membrane oxygenator. Observational trial. University hospital. Prototype filter for volatile agents. The prototype filter was tested in a single ex vivo experiment. The main data measured during the test were pressure drop to detect interference with the performance of the oxygenator, back pressure to detect overpressure to the outlet gas jacket of the oxygenator, analysis of exhaled sevoflurane after the membrane oxygenator, and after the filter to detect any presence of sevoflurane. The prototype filter adsorbed the sevoflurane eliminated through the outlet portion of the oxygenator. During the entire test, the back pressure remained constant (4 mmHg) and pressure drop varied from 243 mmHg to 247 mmHg. The prototype filter was considered suitable to absorb the sevoflurane, and it did not cause an overpressure to the membrane oxygenator during the test. Copyright © 2017 Elsevier Inc. All rights reserved.

Photothermal IR spectroscopy with perforated membrane micromechanical resonators

DEFF Research Database (Denmark)

Kurek, Maksymilian

-IR method. In order to overcome them, string resonators were replaced by membranes. A reliable sampling technique was maintained by adding perforation to membranes and thereby essentially getting membrane porous filters. Membranes gave also access to fully integrated magnetic transduction that allowed...... for significant shrinkage and simplification of the system. An analytical model of a locally heated membrane was developed and confirmed through FEM simulations. Then, low stress silicon nitride perforated membranes were fabricated and characterized using two different experimental setups that employed optical...

The combined effect of gamma radiation and stress cracking in polycarbonate

International Nuclear Information System (INIS)

Melo, Raphaela N. de; Rabello, Marcelo S.

2009-01-01

In this work the combined effect of gamma irradiation and stress cracking was studied in polycarbonate (PC). Tensile test bars were produced by injection moulding and then exposed to different doses of gamma radiation. After that they were submitted to the contact with isopropanol, the stress cracking agent used in this work. The specimens were tested for mechanical properties, viscosity molecular weight and fractography. The results indicated that the previous radiation intensified the stress cracking effects, as evidenced by the reduction in tensile properties and surface damage caused to the samples. (author)

Independent Control of Adhesive and Bulk Properties of Hybrid Silica Coatings on Polycarbonate

OpenAIRE

Lionti , Krystelle; Cui , Linying; Volksen , Willi; Dauskardt , Reinhold; Dubois , Geraud; Toury , Bérangère

2013-01-01

International audience; Transparent polymers are widely used in many 9 applications ranging from automotive windows to micro-10 electronics packaging. However, their intrinsic characteristics, 11 in particular their mechanical properties, are significantly 12 degraded with exposure to different weather conditions. For 13 instance, under humid environment or UV-irradiation, 14 polycarbonate (PC) undergoes depolymerization, leading to 15 the release of Bisphenol A, a molecule presumed to be a 1...

Visual colorimetry for trace antimony(V) by ion-pair solid-phase extraction with bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III) on a PTFE type membrane filter.

Science.gov (United States)

Mizuguchi, Hitoshi; Matsuda, Yuki; Mori, Takehito; Uehara, Atsushi; Ishikawa, Yuta; Endo, Masatoshi; Shida, Junichi

2008-02-01

A new visual colorimetry for trace antimony(V) based on ion-pair solid-phase extraction to a PTFE-type membrane filter with bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III) ion ([Co(5-Cl-PADAP)(2)](+)) has been developed. Experiments showed that hexachloroantimonate(V) ion (SbCl(6)(-)) was adsorbed with [Co(5-Cl-PADAP)(2)](+) to the front surface of the PTFE filter. The adsorption of antimony(V) ion was promoted by the addition of lithium chloride as a source of chloride ion. The excess reagent of [Co(5-Cl-PADAP)(2)](+) was eluted by rinsing with a 10 wt% methanol aqueous solution. In this case, the slow rate of the hydrolysis reaction of SbCl(6)(-) and the difference of the hydrophobicity of the ion pairs were important for adsorption and separation with a PTFE-type membrane filter. The antimony(V) concentration was determined through a visual comparison with a standard series. The visual detection limit was 0.10 microg. The calibration curve assessed with the reflection spectrometric responses at 580 nm was linear in the concentration range of 0.10 - 1.2 microg (r = 0.996). The proposed method has been applied to the determination of sub-microgram levels of antimony(V) ion in water samples.

Electromigration and Deposition of Micro-Scale Calcium Carbonate Structures with Controlled Morphology and Polymorphism

Science.gov (United States)

2013-04-01

precipitation of calcium carbonate in structured templates including microporous polycarbonate membranes and polyethylene foams. Para- meters...polyethylene foam). Microporous polycarbonate membranes and Medium-Density PolyEthylene (MDPE) foam specimens were used as the porous organic...voids in hardened concrete. DOI:10.1520/C624-06. West Conshohocken, PA: ASTM International . www.astm.org. Bersa, L., and M. Liu. 2007. A review on

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

Investigation of vacuum deposited hybrid coatings of protic organic UV absorbers embedded in a silica matrix used for the UV protection of Polycarbonate glazing

OpenAIRE

Weber, C.; Schulz, U.; Mühlig, C.; Kaiser, N.; Tünnermann, A.

2016-01-01

A study of vacuum-deposited organic-inorganic hybrid coatings for UV protection of polycarbonate is presented. UV-absorbing compounds, which are commonly used for polycarbonate, were embedded in a silica matrix by thermal co-evaporation under high vacuum. In addition to the optical properties of the coatings, the influence of the silica network on the organic UV absorber and the stability of the intramolecular hydrogen bond (IMHB) are discussed. A model is presented to show the interaction be...

EFFECTS OF OZONATION ON THE PERMEATE FLUX OF NANOCRYSTALLINE CERAMIC MEMBRANES. (R830908)

Science.gov (United States)

Titania membranes, with a molecular weight cut-off of 15 kD were used in an ozonation/membrane system that was fed with water from Lake Lansing, which had been pre-filtered through a 0.45 �m glass fiber filter. The application of ozone gas prior to filtration resulted in signi...

Flame assisted synthesis of catalytic ceramic membranes

DEFF Research Database (Denmark)

Johansen, Johnny; Mosleh, Majid; Johannessen, Tue

2004-01-01

technology it is possible to make supported catalysts, composite metal oxides, catalytically active surfaces, and porous ceramic membranes. Membrane layers can be formed by using a porous substrate tube (or surface) as a nano-particle filter. The aerosol gas from the flame is led through a porous substrate...

Temperature and time dependence of free volume in bisphenol A polycarbonate studied by positron lifetime spectroscopy

NARCIS (Netherlands)

Kluin, J.E.; Yu, Z.; Vleeshouwers, S.M.; McGervey, J.D.; Jamieson, A.M.; Simha, R.

1992-01-01

New positron lifetime expts. were carried out for Bisphenol-A polycarbonate. The influence of unavoidable pos. charged positron irradn. on the lifetime and intensity of o-positronium (o-Ps) annihilation was studied. Results obtained using a state-of-the-art lifetime spectrometer (count rate 670 cps

Wetting and other physical characteristics of polycarbonate surface textured using laser ablation

Energy Technology Data Exchange (ETDEWEB)

Yilbas, B.S., E-mail: bsyilbas@kfupm.edu.sa [ME Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Khaled, M. [CHEM Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Abu-Dheir, N.; Al-Aqeeli, N.; Said, S.A.M. [ME Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Ahmed, A.O.M. [CHEM Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Varanasi, K.K.; Toumi, Y.K. [Mechanical Engineering, Massachusetts Institute of Technology, Boston (United States)

2014-11-30

Highlights: • Laser causes micro/nano size pores and shallow fine-size cavities. • Crystallinity at surface is 18% after laser treatment increasing hydrophobicity. • Surface hydrophobicity improves after laser treatment. • Microhardness increases twofold after laser treatment process. • Residual stress is compressive and scratch hardness is 110 ± 11 MPa. • Optical transmittance reduces by 15% after laser treatment. - Abstract: Surface texturing of polycarbonate glass is carried out for improved hydrophobicity via controlled laser ablation at the surface. Optical and physical characteristics of the laser treated layer are examined using analytical tools including optical, atomic force, and scanning electron microscopes, Fourier transform infrared spectroscopy, and X-ray diffraction. Contact angle measurements are carried out to assess the hydrophobicity of the laser treated surface. Residual stress in the laser ablated layer is determined using the curvature method, and microhardnes and scratch resistance are analyzed using a micro-tribometer. Findings reveal that textured surfaces compose of micro/nano pores with fine cavities and increase the contact angle to hydrophobicity such a way that contact angles in the range of 120° are resulted. Crystallization of the laser treated surface reduces the optical transmittance by 15%, contributes to residual stress formation, and enhances the microhardness by twice the value of untreated polycarbonate surface. In addition, laser treatment improves surface scratch resistance by 40%.

Filtration through nylon membranes negatively affects analysis of arsenic and phosphate by the molybdenum blue method

DEFF Research Database (Denmark)

Heimann, Axel Colin; Jakobsen, Rasmus

2007-01-01

Filtering synthetic arsenic- or phosphate-containing solutions (1.5-47.6 mu mol/L) with nylon syringe filters significantly reduced absorbances (by 6-74%) when analyzed with the colorimetric molybdenum blue method. Filtering the same solutions with cellulose acetate syringe filters yielded...... no significant differences as compared to unfiltered controls. The detrimental effect of nylon membranes was also observed when pure Milli-Q water was filtered and Subsequently spiked with arsenic(III) or phosphate suggesting that some compound(s) eluting from the filter membranes interfere with the color...... formation in the assay. Consequently, we caution against using nylon filters when filtering water samples for the determination of arsenic or phosphate with the molybdenum blue method....

Modification of polycarbonate surface in oxidizing plasma

Science.gov (United States)

Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

2017-11-01

The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

Science.gov (United States)

Tanimoto, Yasuhiro; Inami, Toshihiro; Yamaguchi, Masaru; Nishiyama, Norihiro; Kasai, Kazutaka

2015-05-01

Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion. After fabricating these GFRP round wires with a diameter of 0.45 mm (0.018 inch), we examined their mechanical and in vitro properties. To investigate how the glass-fiber diameter affected their physical properties, we prepared GFRP wires of varying diameters (7 and 13 µm). Both the GFRP with 13-µm fibers (GFRP-13) and GFRP with 7 µm fibers (GFRP-7) were more transparent than the metallic orthodontic wires. Flexural strengths of GFRP-13 and GFRP-7 were 690.3 ± 99.2 and 938.1 ± 95.0 MPa, respectively; flexural moduli of GFRP-13 and GFRP-7 were 25.4 ± 4.9 and 34.7 ± 7.7 GPa, respectively. These flexural properties of the GFRP wires were nearly equivalent to those of available Ni-Ti wires. GFRP-7 had better flexural properties than GFRP-13, indicating that the flexural properties of GFRP increase with decreasing fiber diameter. Using thermocycling, we found no significant change in the flexural properties of the GFRPs after 600 or 1,200 cycles. Using a cytotoxicity detection kit, we found that the glass fiber and polycarbonate components comprising the GFRP were not cytotoxic within the limitations of this study. We expect this metal-free GFRP wire composed of polycarbonate and glass fiber to be useful as an esthetically pleasing alternative to current metallic orthodontic wire. © 2014 Wiley Periodicals, Inc.

Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water

Directory of Open Access Journals (Sweden)

Md Shafiquzzaman

2018-02-01

Full Text Available The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW. The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs. Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480–2000 L/m2/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe, and manganese (Mn. The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m2/d, thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m2/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW.

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

Science.gov (United States)

de Freitas, Normanda L; Gonçalves, José A S; Innocentini, Murilo D M; Coury, José R

2006-08-25

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Biosensors Based on Ultrathin Film Composite Membranes

Science.gov (United States)

1994-01-25

composite membranes should have a number C •’ of potential advantages including fast response time, simplicity of construction, and applicability to a number...The support membrane for the ultrathin film composite was an Anopore ( Alltech Associates) microporous alumina filter, these membranes are 55 Pm thick...constant 02 concentration in this solution. Finally, one of the most important potential advantage of a sensor based on an ultrathin film composite

Membrane processes for the reuse of car washing wastewater

Directory of Open Access Journals (Sweden)

Deniz Uçar

2018-04-01

Full Text Available This study investigates alternative treatments of car wash effluents. The car wash wastewater was treated by settling, filtration, and membrane filtration processes. During settling, total solid concentration decreased rapidly within the first 2 hours and then remained constant. Chemical oxygen demand (COD and conductivity were decreased by 10% and 4%, respectively. After settling, wastewater was filtered throughout a 100 μm filter. It was found that filtration had a negligible effect on COD removal. Finally, wastewater was filtered by four ultrafiltration membranes of varying molecular weight cutoff (MWCO (1, 5, 10 and 50 kDa and one nanofiltration membrane (NF270, MWCO = 200–400 Da. The permeate COD concentrations varied between 64.5 ± 3.2 and 85.5 ± 4.3 mg L−1 depending on UF pore size. When the NF270 nanofiltration membrane was used, the permeate COD concentration was 8.1 ± 0.4 mg L−1 corresponding to 97% removal. FeCl3 precipitation and activated carbon adsorption techniques were also applied to the retentate and 60–76% COD removals were obtained for activated carbon adsorption and FeCl3 precipitation, respectively.

Evaluation of personal inhalable aerosol samplers with different filters for use during anthrax responses.

Science.gov (United States)

Grinshpun, Sergey A; Weber, Angela M; Yermakov, Michael; Indugula, Reshmi; Elmashae, Yousef; Reponen, Tiina; Rose, Laura

2017-08-01

Risk of inhalation exposure to viable Bacillus anthracis (B. anthracis) spores has primarily been assessed using short-term, stationary sampling methods which may not accurately characterize the concentration of inhalable-sized spores reaching a person's breathing zone. While a variety of aerosol sampling methods have been utilized during previous anthrax responses, no consensus has yet been established for personal air sampling. The goal of this study was to determine the best sampler-filter combination(s) for the collection and extraction of B. anthracis spores. The study was designed to (1) evaluate the performance of four filter types (one mixed cellulose ester, MCE (pore size = 3 µm), two polytetrafluoroethylene, PTFE (1 and 3 µm), and one polycarbonate, PC (3 µm)); and (2) evaluate the best performing filters in two commercially available inhalable aerosol samplers (IOM and Button). Bacillus thuringiensis kurstaki [Bt(k)], a simulant for B. anthracis, served as the aerosol challenge. The filters were assessed based on criteria such as ability to maintain low pressure drop over an extended sampling period, filter integrity under various environmental conditions, spore collection and extraction efficiencies, ease of loading and unloading the filters into the samplers, cost, and availability. Three of the four tested collection filters-except MCE-were found suitable for efficient collection and recovery of Bt(k) spores sampled from dry and humid as well as dusty and clean air environments for up to 8 hr. The PC (3 µm) filter was identified as the best performing filter in this study. The PTFE (3 µm) demonstrated a comparable performance, but it is more expensive. Slightly higher concentrations were measured with the IOM inhalable sampler which is the preferred sampler's performance criterion when detecting a highly pathogenic agent with no established "safe" inhalation exposure level. Additional studies are needed to address the effects of

Crud separation from equipment drain of BWR atomic power station

International Nuclear Information System (INIS)

Hayashi, Masaru; Yamaguchi, Hisashi; Moriya, Yasuhiro; Koshiba, Yukihiko; Ota, Yoshiharu.

1977-01-01

In the primary cooling systems of BWR nuclear power stations, radioactive crud is generated and accumulates in reactors and circulating systems, which causes the radiation exposure of workers at the time of the inspection and maintenance of reactors. The chemical composition and grain size distribution of crud differ largely according to the construction of primary systems, the operational conditions of reactors, and the process of operation. The study on the application of nuclear pore membrane filter NPMF to the separation of crud in the waste water from equipment drain systems has been carried out. With the NPMF, clarified filtrate can be obtained without any filter aid, therefore the secondary waste of filter sludge is not generated. When the filter is clogged, the filtration capability can be regenerated by reverse flow washing, and continuous filtration is possible actually because the regeneration takes only short time. The NPMF is the polycarbonate membrane of about 10 μm thick, to which charged particles are irradiated vertically, and the flight tracks are etched with alkali solution, thus the required pore treatment is applied. The basic investigation of waste liquid, the endurance test of actual filters, the filtration test with the pilot apparatus, the demonstration test with an actual equipment, and the design of the actual equipment have been carried out for three years. (Kako, I.)

Miscibility evolution of polycarbonate/polystyrene blends during compounding

DEFF Research Database (Denmark)

Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib

2002-01-01

The miscibility evolution of polycarbonate/polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, remelt blending in a twin-screw extruder and third melt blending in an injection molding machine, was investigated...... polymer in the other. The observed solubility strongly depends on blend composition and blending method. The T-g measurements showed maximum mutual solubility around 50/50 composition. The miscibility of PC/PS blended after the third stage (melt injection molding) was higher than that after the first...... by measuring their glass transition temperatures (T-g) and their specific heat increment (DeltaC(p)). Differential scanning calorimetry (DSC) was used to examine nine blend compositions. Shifts in glass transition temperature (T-g) of the two phases in melt-mixed PC/PS blends suggest partial miscibility of one...

A review on bisphenol A occurrences, health effects and treatment process via membrane technology for drinking water.

Science.gov (United States)

Muhamad, Mimi Suliza; Salim, Mohd Razman; Lau, Woei Jye; Yusop, Zulkifli

2016-06-01

Massive utilization of bisphenol A (BPA) in the industrial production of polycarbonate plastics has led to the occurrence of this compound (at μg/L to ng/L level) in the water treatment plant. Nowadays, the presence of BPA in drinking water sources is a major concern among society because BPA is one of the endocrine disruption compounds (EDCs) that can cause hazard to human health even at extremely low concentration level. Parallel to these issues, membrane technology has emerged as the most feasible treatment process to eliminate this recalcitrant contaminant via physical separation mechanism. This paper reviews the occurrences and effects of BPA toward living organisms as well as the application of membrane technology for their removal in water treatment plant. The potential applications of using polymeric membranes for BPA removal are also discussed. Literature revealed that modifying membrane surface using blending approach is the simple yet effective method to improve membrane properties with respect to BPA removal without compromising water permeability. The regeneration process helps in maintaining the performances of membrane at desired level. The application of large-scale membrane process in treatment plant shows the feasibility of the technology for removing BPA and possible future prospect in water treatment process.

Ceramic membrane development in NGK

Energy Technology Data Exchange (ETDEWEB)

Araki, Kiyoshi; Sakai, Hitoshi, E-mail: kinsakai@ngk.co.jp [Corporate R and D, NGK Insulators, Ltd., Nagoya 467-8530 (Japan)

2011-05-15

NGK Insulators, Ltd. was established in 1919 to manufacture the electric porcelain insulators for power transmission lines. Since then, our business has grown as one of the world-leading ceramics manufacturing companies and currently supply with the various environmentally-benign ceramic products to worldwide. In this paper, ceramic membrane development in NGK is described in detail. We have been selling ceramic microfiltration (MF) membranes and ultra-filtration (UF) membranes for many years to be used for solid/liquid separation in various fields such as pharmaceutical, chemical, food and semiconductor industries. In Corporate R and D, new ceramic membranes with sub-nanometer sized pores, which are fabricated on top of the membrane filters as support, are under development for gas and liquid/liquid separation processes.

Ceramic membrane development in NGK

Science.gov (United States)

Araki, Kiyoshi; Sakai, Hitoshi

2011-05-01

NGK Insulators, Ltd. was established in 1919 to manufacture the electric porcelain insulators for power transmission lines. Since then, our business has grown as one of the world-leading ceramics manufacturing companies and currently supply with the various environmentally-benign ceramic products to worldwide. In this paper, ceramic membrane development in NGK is described in detail. We have been selling ceramic microfiltration (MF) membranes and ultra-filtration (UF) membranes for many years to be used for solid/liquid separation in various fields such as pharmaceutical, chemical, food and semiconductor industries. In Corporate R&D, new ceramic membranes with sub-nanometer sized pores, which are fabricated on top of the membrane filters as support, are under development for gas and liquid/liquid separation processes.

Protein Adsorption to In-Line Filters of Intravenous Administration Sets.

Science.gov (United States)

Besheer, Ahmed

2017-10-01

Ensuring compatibility of administered therapeutic proteins with intravenous administration sets is an important regulatory requirement. A low-dose recovery during administration of low protein concentrations is among the commonly observed incompatibilities, and it is mainly due to adsorption to in-line filters. To better understand this phenomenon, we studied the adsorption of 4 different therapeutic proteins (2 IgG1s, 1 IgG4, and 1 Fc fusion protein) diluted to 0.01 mg/mL in 5% glucose (B. Braun EcoFlac; B. Braun Melsungen AG, Melsungen, Germany) or 0.9% sodium chloride (NaCl; Freeflex; Fresenius Kabi, Friedberg, Germany) solutions to 8 in-line filters (5 positively charged and 3 neutral filters made of different polymers and by different suppliers). The results show certain patterns of protein adsorption, which depend to a large extent on the dilution solution and filter material, and to a much lower extent on the proteins' biophysical properties. Investigation of the filter membranes' zeta potential showed a correlation between the observed adsorption pattern in 5% glucose solution and the filter's surface charge, with higher protein adsorption for the strongly negatively charged membranes. In 0.9% NaCl solution, the surface charges are masked, leading to different adsorption patterns. These results contribute to the general understanding of the protein adsorption to IV infusion filters and allow the design of more efficient compatibility studies. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Air effect on polycarbonate radiolysis; Efeito do ar na radiolise do policarbonato

Energy Technology Data Exchange (ETDEWEB)

Terence, Mauro C.; Araujo, Elmo S.; Guedes, Selma M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1995-12-31

The formation and decay of radicals in the radiolysis of new type of polycarbonate (G{sub scission} = 0,73) was investigated by electron spin resonance spectroscopy in the presence and absence of air at room temperature. The air does not interfere in the formation of radicals because they are formed as consequence of direct interaction of radiation. But the air interferes in their decays. During the irradiation the air reacts with all isopropyl radicals and with 2/3 of phenoxy + phenyl radicals. (author). 5 refs., 3 figs.

A dense cell retention culture system using stirred ceramic membrane reactor.

Science.gov (United States)

Suzuki, T; Sato, T; Kominami, M

1994-11-20

A novel reactor design incorporating porous ceramic tubes into a stirred jar fermentor was developed. The stirred ceramic membrane reactor has two ceramic tubular membrane units inside the vessel and maintains high filtration flux by alternating use for filtering and recovering from clogging. Each filter unit was linked for both extraction of culture broth and gas sparging. High permeability was maintained for long periods by applying the periodical control between filtering and air sparging during the stirred retention culture of Saccharomyces cerevisiae. The ceramic filter aeration system increased the k(L)a to about five times that of ordinary gas sparing. Using the automatic feeding and filtering system, cell mass concentration reached 207 g/L in a short time, while it was 64 g/L in a fed-batch culture. More than 99% of the growing cells were retained in the fermentor by the filtering culture. Both yield and productivity of cells were also increased by controlling the feeding of fresh medium and filtering the supernatant of the dense cells culture. (c) 1994 John Wiley & Sons, Inc.

Gamma radiation effects on polycarbonate-Durolon

International Nuclear Information System (INIS)

Miranda, Adelina.

1996-01-01

In this work, the commercial polycarbonate-Durolon, was characterized through measurements of its mechanical, optical viscosimetric and thermal properties, after being irradiated with a 60 Co gamma-source at IPEN-CNEN/SP. These irradiations were carried out different doses and dose rates in air and in vacuum. From the results obtained it was shown that irradiation causes degradation in PC mainly by chain scission, leading to the formation of phenoxy and phenyl radicals which are associated with the yellowness of the material. Both, the concentration of radicals and yellowness of PC increase with the irradiation doses and dose rates. The irradiated PC-Durolon shown a good mechanical stability up to the doses analyzed, but on the other hand, its optical properties do not have the same performance. The viscosity and glass transition temperature of the Durolon decreases with the increase of dose and dose rates. This behavior indicates that main chain scission is the predominant process during irradiation. Furthermore in PC this degradation is higher when the material is irradiated in air, which shows that oxygen also plays an important role in this degradation process. (author). 37 refs., 30 figs., 4 tabs

Metal membrane with dimer slots as a universal polarizer

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

2014-01-01

In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electr......In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory...

Carbon nanotubes with silver nanoparticle decoration and conductive polymer coating for improving the electrical conductivity of polycarbonate composites

KAUST Repository

Patole, Archana S.; Lubineau, Gilles

2015-01-01

in achieving a uniform dispersion of the Ag/MWCNT-EDA and (2) it acts as a conductive bridge between particles (Ag and MWCNT-EDA), reducing the particle to particle resistivity. When inserted into polycarbonate, this three-phase blend successfully reduced

The dipole moments of the linear polycarbon monosulfides

International Nuclear Information System (INIS)

Murakami, Akinori

1989-01-01

The dipole moments of the linear polycarbon monosulfides, CS, C 2 S and C 3 S molecule (radical)s were calculated by ab initio SCF-CI method. The equilibrium geometries of the C n S molecules were obtained by MP3 method using the 6-31G** basis set. From the split balencetype (MIDI-4) to the Huzinaga's well tempered extended type(WT) were used to evaluate dipole moments. Final results were obtained using the WT+2d basis set and CI calculation. The calculated dipole moment of the CS molecule, 1.96 debye, is in good agreement with experimental one. The dipole moment of the C 2 S radical is calculated to be 2.81 debye and 3.66 debye for C 3 S molecule. The calculated dipole moments of the C n S will be accurate with in 0.1 debye(5%)

Track-Etched Magnetic Micropores for Immunomagnetic Isolation of Pathogens

Science.gov (United States)

Muluneh, Melaku; Shang, Wu

2014-01-01

A microfluidic chip is developed to selectively isolate magnetically tagged cells from heterogeneous suspensions, the track-etched magnetic micropore (TEMPO) filter. The TEMPO consists of an ion track-etched polycarbonate membrane coated with soft magnetic film (Ni20Fe80). In the presence of an applied field, provided by a small external magnet, the filter becomes magnetized and strong magnetic traps are created along the edges of the micropores. In contrast to conventional microfluidics, fluid flows vertically through the porous membrane allowing large flow rates while keeping the capture rate high and the chip compact. By utilizing track-etching instead of conventional semiconductor fabrication, TEMPOs can be fabricated with microscale pores over large areas A > 1 cm2 at little cost ( 500 at a flow rate of Φ = 5 mL h−1. Furthermore, the large density of micropores (ρ = 106 cm−2) allows the TEMPO to sort E. coli from unprocessed environmental and clinical samples, as the blockage of a few pores does not significantly change the behavior of the device. PMID:24535921

Large-scale generation of cell-derived nanovesicles

Science.gov (United States)

Jo, W.; Kim, J.; Yoon, J.; Jeong, D.; Cho, S.; Jeong, H.; Yoon, Y. J.; Kim, S. C.; Gho, Y. S.; Park, J.

2014-09-01

Exosomes are enclosed compartments that are released from cells and that can transport biological contents for the purpose of intercellular communications. Research into exosomes is hindered by their rarity. In this article, we introduce a device that uses centrifugal force and a filter with micro-sized pores to generate a large quantity of cell-derived nanovesicles. The device has a simple polycarbonate structure to hold the filter, and operates in a common centrifuge. Nanovesicles are similar in size and membrane structure to exosomes. Nanovesicles contain intracellular RNAs ranging from microRNA to mRNA, intracellular proteins, and plasma membrane proteins. The quantity of nanovesicles produced using the device is 250 times the quantity of naturally secreted exosomes. Also, the quantity of intracellular contents in nanovesicles is twice that in exosomes. Nanovesicles generated from murine embryonic stem cells can transfer RNAs to target cells. Therefore, this novel device and the nanovesicles that it generates are expected to be used in exosome-related research, and can be applied in various applications such as drug delivery and cell-based therapy.

Track-etched nanopores in spin-coated polycarbonate films applied as sputtering mask

International Nuclear Information System (INIS)

Nix, A.-K.; Gehrke, H.-G.; Krauser, J.; Trautmann, C.; Weidinger, A.; Hofsaess, H.

2009-01-01

Thin polycarbonate films were spin-coated on silicon substrates and subsequently irradiated with 1-GeV U ions. The ion tracks in the polymer layer were chemically etched yielding nanopores of about 40 nm diameter. In a second process, the nanoporous polymer film acted as mask for structuring the Si substrate underneath. Sputtering with 5-keV Xe ions produced surface craters of depth ∼150 nm and diameter ∼80 nm. This arrangement can be used for the fabrication of track-based nanostructures with self-aligned apertures.

The influence of hard segment content on mechanical and thermal properties of polycarbonate-based polyurethane materials

Directory of Open Access Journals (Sweden)

Budinski-Simendić Jaroslava

2012-01-01

Full Text Available Aliphatic segmented polyurethanes were prepared by one-step procedure in catalytic reaction between polycarbonate diol, hexamethylene-diisocyanate and 1,4-butandiol (as chain extender. The hard segment content TS was varied (17, 24, 30 and 42 wt. % by changing the ratio of starting compounds. The soft segment is made from flexible aliphatic polycarbonate diol, while hard segments consist of chain extender and diisocyanate component. In order to study the hydrogen bonding formation and phase separation, Fourier transform infrared spectroscopy (FT-IR was used. Wide angle X-ray scattering (WAXS was performed to determine a degree of crystallinity and to investigate the phase behavior of prepared elastomers. The effect of TS content on mechanical properties (tensile strength, elongation at break and hardness was tested. Thermal behavior of prepared novel polycarbonate-based polyurethanes was investigated using differential scanning callorimetry (DSC. It was determined that the elastomer which contains the highest amount of urethane groups in its structure (TS content of 42 wt. % exhibits the most pronounced phase separation and the highest degree of crystallinity. All prepared polyurethanes exhibit high elongation at break (over 700%. The glass transition temperature Tg of prepared samples was in the temperature region from −39 to −36°C, and it was found to be slightly influenced by the soft segment content. The enthalpy of chain segments relaxation in diffused region between hard and soft domains (detected in the temperature range from 35 to 55 °C was decreased with the increase of hard segment content. The multiple melting of hard segments (connected with the dissruption of physical crosslinks appeared above 100 °C. It was found that the melting enthalpy linearly increases with the increase of urethane group content. Sample with 42 wt. % of TS has the highest value of melting enthalpy (41.5 J/g.

Separations using biological carriers immobilized in porous polymeric and sol-gel template synthesized nanotubular membranes

Science.gov (United States)

Lakshmi, Brinda B.

1998-12-01

The overall goal of the dissertation was to use immobilized biological carriers in membranes to separate compounds as challenging as enantiomers. The membranes were prepared by a process called 'template synthesis'. Template synthesis has been used to synthesize semiconductor nanostructures and also membranes which do the enantioseparation by a process called facilitated transport. The immobilized proteins act as carriers facilitating the transport of the substrate molecules through the membrane. The apoenzymes are enzymes devoid of cofactor. Apoenzymes will possess the molecular recognition site for the substrate but will not catalyze the reaction. Apoenzymes immobilized in the pores of porous polycarbonate membrane was used as a carrier. The ends of the pores were closed with porous polypyrrole. Compounds as interesting as enantiomers were separated with these membranes. Template synthesis has been extended to the synthesis of many important semiconductor oxide naostructures like TiO2, SiO2, ZnO, Co3O4 and MnO2. These structures were made by dipping the alumina template membrane in the sol and heating. Ti0 2 tubules and fibers were obtained by this method. The fibers were used to study photocatalysis reaction of organic compounds in sunlight. Proteins were immobilized within the inner surface of the tubules using Sn chemistry. Bovine serum albumn (BSA) immobilized within the different diameter tubules showed varying degree of facilitation with phenylalanine. The membranes also show interesting switching of selectivity from L to D depending on the tube size and feed concentration.

Use of additives to fine-tune the composition of carbonate units in the polymer formed by copolymerization of co2 with epoxide: application to the synthesis of polycarbonate-based block copolymers and of telechelics

KAUST Repository

Feng, Xiaoshuang

2016-12-22

Embodiments of the present disclosure describe a method of making a polycarbonate, comprising contacting one or more cyclic monomers and carbon dioxide in the presence of one or more of a Lewis acid catalyst, an initiator, and an ionic liquid; and agitating, sufficient to copolymerize the one or more cyclic monomers and carbon dioxide to create a polycarbonate. Embodiments of the present disclosure further describe a method of controlling a polymer composition, comprising contacting one or more cyclic monomers and carbon dioxide; adjusting an amount of one or more of a Lewis acid catalyst, an ionic liquid, and an initiator in the presence of the one or more cyclic monomers and carbon dioxide, sufficient to selectively modify a resulting polycarbonate; and agitating, sufficient to copolymerize the one or more cyclic monomers and carbon dioxide to create the polycarbonate.

Use of additives to fine-tune the composition of carbonate units in the polymer formed by copolymerization of co2 with epoxide: application to the synthesis of polycarbonate-based block copolymers and of telechelics

KAUST Repository

Feng, Xiaoshuang; Zhang, Dongyue; Gnanou, Yves; Hadjichristidis, Nikolaos

2016-01-01

Embodiments of the present disclosure describe a method of making a polycarbonate, comprising contacting one or more cyclic monomers and carbon dioxide in the presence of one or more of a Lewis acid catalyst, an initiator, and an ionic liquid; and agitating, sufficient to copolymerize the one or more cyclic monomers and carbon dioxide to create a polycarbonate. Embodiments of the present disclosure further describe a method of controlling a polymer composition, comprising contacting one or more cyclic monomers and carbon dioxide; adjusting an amount of one or more of a Lewis acid catalyst, an ionic liquid, and an initiator in the presence of the one or more cyclic monomers and carbon dioxide, sufficient to selectively modify a resulting polycarbonate; and agitating, sufficient to copolymerize the one or more cyclic monomers and carbon dioxide to create the polycarbonate.

Filter-separable constituents of groundwater from the Columbia River plateau

International Nuclear Information System (INIS)

Seitz, M.G.; Boggs, S. Jr.

1984-01-01

The purpose of this procedure is to prepare groundwaters from the Columbia River basalt, northeastern Oregon, for batch partitioning experiments by concentration dissolved organic carbon (DOC) in water samples by ultrafiltration. Water samples were double-filtered through 0.4-μm Nuclepore polycarbonate filters to remove particulates before beginning the ultrafiltration process. The results of these experiments do not indicate a consistent relation between the distribution of americium with coexisting basalt and groundwater and the DOC content of the groundwater at 25 0 C, but there is some indication of increasing sorption of americium on basalt with increasing DOC at 90 0 C. However, any simple interpretation of the effects of DOC on the sorption behavior of americium must be made with caution, as there are other variables in the chemistry of the groundwaters that may also have important controls on this process. Another important observation from this set of experiments is that ultrafiltration does not seem to be an effective means of concentrating DOC without affecting the other trace constituents of groundwaters. The observed fractionation of groundwater chemistry as a result of the ultrafiltration procedure is not yet understood. However, for further progress in experiments of this type, it may be necessary to develop an alternative means of concentrating organic compounds that would allow the maintenance of constant values of other trace constituents as an experimental control

Membranes in Lithium Ion Batteries

Science.gov (United States)

Yang, Min; Hou, Junbo

2012-01-01

Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed. PMID:24958286

Membranes in Lithium Ion Batteries

Directory of Open Access Journals (Sweden)

Junbo Hou

2012-07-01

Full Text Available Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.

On the effect of the fiber orientation on the flexural stiffness of injection molded short fiber reinforced polycarbonate plates

NARCIS (Netherlands)

Neves, N.M.; Isdell, G.; Pouzada, A.S.; Powell, P.C.

1998-01-01

The through-thickness fiber orientation distribution of injection molded polycarbonate plates was experimentally determined by light reflection microscopy and manual digitization of polished cross sections. Fiber length distribution was determined by pyrolysis tests followed by image analysis. A

Modeling electrically active viscoelastic membranes.

Directory of Open Access Journals (Sweden)

Sitikantha Roy

Full Text Available The membrane protein prestin is native to the cochlear outer hair cell that is crucial to the ear's amplification and frequency selectivity throughout the whole acoustic frequency range. The outer hair cell exhibits interrelated dimensional changes, force generation, and electric charge transfer. Cells transfected with prestin acquire unique active properties similar to those in the native cell that have also been useful in understanding the process. Here we propose a model describing the major electromechanical features of such active membranes. The model derived from thermodynamic principles is in the form of integral relationships between the history of voltage and membrane resultants as independent variables and the charge density and strains as dependent variables. The proposed model is applied to the analysis of an active force produced by the outer hair cell in response to a harmonic electric field. Our analysis reveals the mechanism of the outer hair cell active (isometric force having an almost constant amplitude and phase up to 80 kHz. We found that the frequency-invariance of the force is a result of interplay between the electrical filtering associated with prestin and power law viscoelasticity of the surrounding membrane. Paradoxically, the membrane viscoelasticity boosts the force balancing the electrical filtering effect. We also consider various modes of electromechanical coupling in membrane with prestin associated with mechanical perturbations in the cell. We consider pressure or strains applied step-wise or at a constant rate and compute the time course of the resulting electric charge. The results obtained here are important for the analysis of electromechanical properties of membranes, cells, and biological materials as well as for a better understanding of the mechanism of hearing and the role of the protein prestin in this mechanism.

CO2-based amphiphilic polycarbonate micelles enable a reliable and efficient platform for tumor imaging

OpenAIRE

Li, Yuanyuan; Liu, Shunjie; Zhao, Xun; Wang, Ying; Liu, Jianhua; Wang, Xianhong; Lu, Lehui

2017-01-01

Biodegradable polymeric nanomaterials can be directly broken down by intracellular processes, offering a desirable way to solve toxicity issues for cancer diagnosis and treatment. Among them, aliphatic polycarbonates are approved for application in biological fields by the United States Food and Drug Administration (FDA), however, high hydrophobicity, deficient functionality and improper degradation offer significant room for improvement in these materials. Methods: To achieve progress in thi...

Improvement of air permeability of Bubbfil nanofiber membrane

Directory of Open Access Journals (Sweden)

Wang Fei-Yan

2018-01-01

Full Text Available Nanofiber membranes always have extremely high filter efficiency and remarkably low pressure drop. In order to further improve air permeability of bubbfil nanofiber membranes, the plasma technology is used for surface treatment in this paper. The results show that plasma treatment can improve air permeability by 4.45%. Under higher power plasma treatment, earthworm like etchings are produced on the membrane surface with fractal dimensions of about 1.138.

Liquid nitrogen enhancement of alpha particle tracks in a polycarbonate detector

International Nuclear Information System (INIS)

Pilione, L.J.

1977-01-01

Makrofol-E polycarbonate detectors were exposed to 1 to 3 MeV alpha particles and subsequently immersed in liquid nitrogen for various periods of time. The influence of the liquid nitrogen on the track recording properties of the detector has been found by measuring the track densities and diameters. Track densities increase with immersion time with a maximum gain of approximately 9% after 1200 min in liquid nitrogen. Track enhancement decreases with waiting time between the end of alpha particle exposure and the beginning of liquid nitrogen immersion. Track diameters decrease with time after passage of the particles and this process is accelerated by immersion in liquid nitrogen. (author)

THE USE OF BIOREACTORS COUPLED WITH MEMBRANES FOR THE TREATMENT OF EFFLUENTS

Directory of Open Access Journals (Sweden)

Bergamasco R.

1997-01-01

Full Text Available The objectives of this paper are to verify the viability of operating a bioreactor coupled with a membrane, and to analyze the global mechanisms witch need to be considered in the bioreactional concept in the separation by membrane. In order to meet the proposed objectives, a culture with a synthetic substratum (ethanol was utilized. A mineral membrane with the following characteristics was used: a pore diameter of 0.2 m m, 19 channels of a 4 mm diameter, a width of 0.85 m, a filtering surface area of 0.2 m2, a pressure of 2 bar and a tangential velocity of 2 m/s. The experiments consisted of modifying the residence time of the substratum within the reactor. The following measurements were taken: chemical oxygen demand (COD, concentration of biomass and filtered flow. The results show a treated effluent of good quality, indicating that the time of hydraulic residence time influences the efficiency of the system and is influenced by the restriction of the filtered flow by a fast fouling of the membrane

A comparative study of track registration response of Makrofol-(KG, KL and N) polycarbonate to sup 4 sup 0 Ar ions

CERN Document Server

Kumar, A

1999-01-01

In the present work a comparative study of track registration response of sup 4 sup 0 Ar ions in different types of Makrofol polycarbonates viz. Makrofol-KG, KL and N have been done. The etched track parameters viz. bulk etch rate, track etch rate, etch rate ratio, cone angle and etching efficiency were calculated. The variation of etching rates with temperature were found to be exponential and follow the Arrhenius equation. The values of activation energy for bulk and track etching were also calculated. Maximum etchable track length/range were also obtained and compared with the theoretical values obtained from computer program RANGE. From the results it is found that the polycarbonates having same chemical composition manufactured by different chemical processes have slightly different behavior

Evaluation of failure characteristics and bond strength after ceramic and polycarbonate bracket debonding : effect of bracket base silanization

NARCIS (Netherlands)

Ozcan, M.; Finnema, K.; Ybema, A.

The objectives of this study were to evaluate the effect of silanization on the failure type and shear-peel bond strength (SBS) of ceramic and polycarbonate brackets, and to determine the type of failure when debonded with either a universal testing machine or orthodontic pliers. Silanized and

Heterogeneous counting on filter support media

International Nuclear Information System (INIS)

Long, E.; Kohler, V.; Kelly, M.J.

1976-01-01

Many investigators in the biomedical research area have used filter paper as the support for radioactive samples. This means that a heterogeneous counting of sample sometimes results. The count rate of a sample on a filter will be affected by positioning, degree of dryness, sample application procedure, the type of filter, and the type of cocktail used. Positioning of the filter (up or down) in the counting vial can cause a variation of 35% or more when counting tritiated samples on filter paper. Samples of varying degrees of dryness when added to the counting cocktail can cause nonreproducible counts if handled improperly. Count rates starting at 2400 CPM initially can become 10,000 CPM in 24 hours for 3 H-DNA (deoxyribonucleic acid) samples dried on standard cellulose acetate membrane filters. Data on cellulose nitrate filters show a similar trend. Sample application procedures in which the sample is applied to the filter in a small spot or on a large amount of the surface area can cause nonreproducible or very low counting rates. A tritiated DNA sample, when applied topically, gives a count rate of 4,000 CPM. When the sample is spread over the whole filter, 13,400 CPM are obtained with a much better coefficient of variation (5% versus 20%). Adding protein carrier (bovine serum albumin-BSA) to the sample to trap more of the tritiated DNA on the filter during the filtration process causes a serious beta absorption problem. Count rates which are one-fourth the count rate applied to the filter are obtained on calibrated runs. Many of the problems encountered can be alleviated by a proper choice of filter and the use of a liquid scintillation cocktail which dissolves the filter. Filter-Solv has been used to dissolve cellulose nitrate filters and filters which are a combination of cellulose nitrate and cellulose acetate. Count rates obtained for these dissolved samples are very reproducible and highly efficient

Molecular modeling of polycarbonate materials: Glass transition and mechanical properties

Science.gov (United States)

Palczynski, Karol; Wilke, Andreas; Paeschke, Manfred; Dzubiella, Joachim

2017-09-01

Linking the experimentally accessible macroscopic properties of thermoplastic polymers to their microscopic static and dynamic properties is a key requirement for targeted material design. Classical molecular dynamics simulations enable us to study the structural and dynamic behavior of molecules on microscopic scales, and statistical physics provides a framework for relating these properties to the macroscopic properties. We take a first step toward creating an automated workflow for the theoretical prediction of thermoplastic material properties by developing an expeditious method for parameterizing a simple yet surprisingly powerful coarse-grained bisphenol-A polycarbonate model which goes beyond previous coarse-grained models and successfully reproduces the thermal expansion behavior, the glass transition temperature as a function of the molecular weight, and several elastic properties.

Monitoring of airborne PM2.5 in the 3d and 4th industrial complex area of Daejeon city in Korea

International Nuclear Information System (INIS)

Moon, Jong Hwa; Chung, Yong Sam; Lim, Jong Myoung; Lee, Jin Hong

2007-01-01

The aim of this research is to enhance the use of a nuclear analytical technique (instrumental neutron activation analysis) in the field of air pollution studies through a routine and long-term monitoring. For the collection of fine airborne particulate matter (<2.5 μm EAD), the Gent stacked filter unit (a low volume sampler) and polycarbonate membrane filters were employed. Samples were collected with selected sampling dates at the 3rd and 4th industrial complex of Daejeon city in Korea. Mass concentration of the air particulates was measured and the elemental content in the samples collected were analyzed by using INAA. Variations of the concentrations of the particulate matter and the enrichment factors for the elements analyzed were determined. From the monitoring data, a factor analysis was performed to identify and to classify the emission sources. (author)

On the penetration of etchant into tracks in polycarbonate

International Nuclear Information System (INIS)

Fink, D.; Dwivedi, K.K.; Mueller, M.; Ghosh, S.; Hnatowicz, V.; Vacik, J.; Cervena, J.

2000-01-01

The time dependence of the uptake of NaOH/LiOH etchant in pristine polycarbonate (PC) and in PC irradiated with 3 GeV Pb ions has been examined. Different stages of etchant penetration can be distinguished. The overall surface-near etchant uptake along tracks is always higher than the the one of the nonirradiated pristine material. Furthermore, the directional dependence of the etchant penetration during the incubation time is studied. Though the shapes of the etchant distributions along the tracks are practically the same in all directions, they differ in their absolute magnitudes. This can be explained by the different cross-sectional track areas exposed at the surface, which enable different etchant penetration efficiencies. Therefore, tracks which run more or less parallel to the surface normal show less etchant uptake than those being strongly tilted

Irradiation effects in polycarbonate induced by 2.1 GeV Kr ions

International Nuclear Information System (INIS)

Tian Huixian; Jin Yunfan; Zhu Zhiyong; Liu Changlong; Sun Youmei; Wang Zhiguang; Liu Jie; Chen Xiaoxi; Wang Yanbin; Hou Mingdong

2002-01-01

Polycarbonate films were irradiated with 2.1 GeV Kr ions at room temperature in vacuum and in atmosphere, respectively. The ion beam induced effects were studied by means of Fourier transform infrared (FTIR) and ultraviolet visible (UV/VIS) spectroscopies in reflective mode. FTIR measurements indicate that the main effects are bond breaking, chain scissions and bond rearrangement. The creation of alkyne is the result of bond breaking and bond rearrangement. UV/VIS measurements indicate that at wavelengths of 380, 450 and 500 nm, the normalized absorbances follow approximately a linear relationship with the energy deposited density

Ceramic membrane in production of recycled water; Keraamikalvo uusioveden valmistuksessa - EKT 05

Energy Technology Data Exchange (ETDEWEB)

Laitinen, N.; Luonsi, A.; Levaenen, E.; Maentylae, T.; Vilen, J. [Haemeen ympaeristoekeskus, Tampere (Finland)

1998-12-31

Applicability of ceramic ultrafiltration membrane modifications were studied with laboratory units to purify clear filtrate and biologically treated combined wastewater from high quality board manufacturing process for reuse. Also performance of polymeric membrane and ceramic membrane was compared. The performance of the membrane filtration cell, developed according to requirements of the fixed dimensions of ceramic membrane was compared with the performance of the cross-rotational commercial test unit (CR-filter) of polymeric membranes. The quality of ultrafiltration permeate, namely suspended solids, turbidity and colour, was better than the quality of lake water used in the mill. The permeate fluxes were in the range of 60-75 l/m{sup 2}h. The fouling layer primarily controlled the flux and the retention, leaving the effects of surface modifications as the secondary function. The flux was slightly higher with the biologically treated wastewater. Differences in membrane material and pore size had an effect on the cleaning ability of the membranes. The polymeric membrane and the membrane with smaller pore size were easier to clean. Tests with the CR-filter showed that the rotor increases shear forces, reduces the filtration resistance and thus increases the flux compared to the cell for ceramic membranes where the increase of shear forces can be done by increasing the flow velocities. (orig.)

Ceramic membrane in production of recycled water; Keraamikalvo uusioveden valmistuksessa - EKT 05

Energy Technology Data Exchange (ETDEWEB)

Laitinen, N; Luonsi, A; Levaenen, E; Maentylae, T; Vilen, J [Haemeen ympaeristoekeskus, Tampere (Finland)

1999-12-31

Applicability of ceramic ultrafiltration membrane modifications were studied with laboratory units to purify clear filtrate and biologically treated combined wastewater from high quality board manufacturing process for reuse. Also performance of polymeric membrane and ceramic membrane was compared. The performance of the membrane filtration cell, developed according to requirements of the fixed dimensions of ceramic membrane was compared with the performance of the cross-rotational commercial test unit (CR-filter) of polymeric membranes. The quality of ultrafiltration permeate, namely suspended solids, turbidity and colour, was better than the quality of lake water used in the mill. The permeate fluxes were in the range of 60-75 l/m{sup 2}h. The fouling layer primarily controlled the flux and the retention, leaving the effects of surface modifications as the secondary function. The flux was slightly higher with the biologically treated wastewater. Differences in membrane material and pore size had an effect on the cleaning ability of the membranes. The polymeric membrane and the membrane with smaller pore size were easier to clean. Tests with the CR-filter showed that the rotor increases shear forces, reduces the filtration resistance and thus increases the flux compared to the cell for ceramic membranes where the increase of shear forces can be done by increasing the flow velocities. (orig.)

Novel single-cell mega-size chambers for electrochemical etching of panorama position-sensitive polycarbonate ion image detectors

Science.gov (United States)

Sohrabi, Mehdi

2017-11-01

A novel development is made here by inventing panorama single-cell mega-size electrochemical etching (MS-ECE) chamber systems for processing panorama position-sensitive mega-size polycarbonate ion image detectors (MS-PCIDs) of potential for many neutron and ion detection applications in particular hydrogen ions or proton tracks and images detected for the first time in polycarbonates in this study. The MS-PCID is simply a large polycarbonate sheet of a desired size. The single-cell MS-ECE invented consists of two large equally sized transparent Plexiglas sheets as chamber walls holding a MS-PCID and the ECE chamber components tightly together. One wall has a large flat stainless steel electrode (dry cell) attached to it which is directly in contact with the MS-PCID and the other wall has a rod electrode with two holes to facilitate feeding and draining out the etching solution from the wet cell. A silicon rubber washer plays the role of the wet cell to hold the etchant and the electrical insulator to isolate the dry cell from the wet cell. A simple 50 Hz-HV home-made generator provides an adequate field strength through the two electrodes across the MS-ECE chamber. Two panorama single-cell MS-ECE chamber systems (circular and rectangular shapes) constructed were efficiently applied to processing the MS-PCIDs for 4π ion emission image detection of different gases in particular hydrogen ions or protons in a 3.5 kJ plasma focus device (PFD as uniquely observed by the unaided eyes). The panorama MS-PCID/MS-ECE image detection systems invented are novel with high potential for many applications in particular as applied to 4π panorama ion emission angular distribution image detection studies in PFD space, some results of which are presented and discussed.

Multi-wavelength Characterization of Brown and Black Carbon from Filter Samples

Science.gov (United States)

Johnson, M. M.; Yatavelli, R. L. N.; Chen, L. W. A. A.; Gyawali, M. S.; Arnott, W. P.; Wang, X.; Chakrabarty, R. K.; Moosmüller, H.; Watson, J. G.; Chow, J. C.

2014-12-01

Particulate matter (PM) scatters and absorbs solar radiation and thereby affects visibility, the Earth's radiation balance, and properties and lifetimes of clouds. Understanding the radiative forcing (RF) of PM is essential to reducing the uncertainty in total anthropogenic and natural RF. Many instruments that measure light absorption coefficients (βabs [λ], Mm-1) of PM have used light at near-infrared (NIR; e.g., 880 nm) or red (e.g., 633 nm) wavelengths. Measuring βabs over a wider wavelength range, especially including the ultraviolet (UV) and visible, allows for contributions from black carbon (BC), brown carbon (BrC), and mineral dust (MD) to be differentiated. This will help to determine PM RF and its emission sources. In this study, source and ambient samples collected on Teflon-membrane and quartz-fiber filters are used to characterize and develop a multi-wavelength (250 - 1000 nm) filter-based measurement method of PM light absorption. A commercially available UV-visible spectrometer coupled with an integrating sphere is used for quantifying diffuse reflectance and transmittance of filter samples, from which βabs and absorption Ǻngström exponents (AAE) of the PM deposits are determined. The filter-based light absorption measurements of laboratory generated soot and biomass burning aerosol are compared to 3-wavelength photoacoustic absorption measurements to evaluate filter media and loading effects. Calibration factors are developed to account for differences between filter types (Teflon-membrane vs. quartz-fiber), and between filters and in situ photoacoustic absorption values. Application of multi-spectral absorption measurements to existing archived filters, including specific source samples (e.g. diesel and gasoline engines, biomass burning, dust), will also be discussed.

Process and device for changing a filter located in a vessel without breaking the confinement of the contaminated area

International Nuclear Information System (INIS)

Mueller, Georges.

1982-01-01

From the non contaminated area, the filter is enclosed in a leak tight bag which is affixed to the outside periphery of a supporting frame. The filter is placed in the bottom of the bag which is then welded in two places, a cut is then made between the two welds to achieve a sealed membrane separating the two halves of the vessel. An additional supporting frame is then placed on the frame. The new filter is secured in place and the sealed membrane is withdrawn from the contaminated part of the vessel [fr

Standard Test Method for Impact Resistance of Monolithic Polycarbonate Sheet by Means of a Falling Weight

CERN Document Server

American Society for Testing and Materials. Philadelphia

1995-01-01

1.1 This test method covers the determination of the energy required to initiate failure in monolithic polycarbonate sheet material under specified conditions of impact using a free falling weight. 1.2 Two specimen types are defined as follows: 1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support. 1.2.2 Type B consists of a simply supported three-point loaded beam specimen (Fig. 1) and is recommended for use with material which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum drop weight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (1/2 in.) thick will probably require use of the Type B specimen. Note 1 - See also ASTM Methods: D 1709, D 2444 and D 3029. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of reg...

Photostabilizing of bisphenol A polycarbonate by using UV-absorbers and self protective block copolymers based on resorcinol polyarylate blocks

NARCIS (Netherlands)

Diepens, M.; Gijsman, P.

2009-01-01

Bisphenol A polycarbonate degrades due to sunlight, humidity and oxygen. In this study two possible techniques to stabilize the polymer were compared, i.e. blending of UV-absorbers (UVAs) into the polymer or using block copolymers based on resorcinol polyarylates. Combination of different analysis

Early cystic bleb needling revision after glaucoma filtering surgery with toxic keratopathy

Directory of Open Access Journals (Sweden)

S. Yu. Petrov

2015-01-01

Full Text Available Clinical case of high thin-wall cystic limited filtering bleb needling revision in the early post-op period after trabeculectomy with sinusotomy accompanied by toxic keratopathy is presented. Optical coherence tomography (OCT demonstrated that filtering bleb height was 2700 μm and bleb wall thickness was 70 μm. Bleb needling revision with its lateralwall dissection and subconjunctival injection of dexamethasone, fluorouracil, and ranibizumab near to the bleb site was performed. In 1.5 hours after the procedure, bleb height decreased to 550 μm (by 5 times while bleb wall thickness increased up to 100 μm. Topical antibacterial, steroid, and non-steroid anti-inflammatory therapy was recommended. The next day IOP level reduced from 11 mm Hg to 4.5 mm Hg. It was accompanied by choroidal effusion that was managed conservatively with cycloplegic agents (drops and injections for 3 days. On day 6, central corneal edema affecting all layers, Descemet’s membrane folds, and ocular hypertension were revealed. Metabolic therapy resolved corneal edema within 3 days. Re-needling bleb revision decreased IOP level to 6.2 mm Hg. This resulted in transient Descemet’s membrane folds. This paper describes filtering bleb needling revision with its lateral wall dissection and anti-inflammatory, cytostatic, and anti-VEGF agents use to prolong glaucoma filtering surgery effect in excessive scarring. The procedure was accompanied by toxic corneal endothelium decompensation with corneal edema and Descemet’s membrane folds treated with active metabolic therapy.

Study on low level radioactive wastewater treatment by inorganic membrane permeation combined with complexation

International Nuclear Information System (INIS)

Li Junfeng; Wang Jianlong; Bai Qinzhong

2007-01-01

Inorganic membranes exhibit greater mechanical durability in some operations than polymeric membranes. They do not suffer from the performance degradation that was resulted from compaction of the membrane structure under pressure or ageing. Membrane permeation combined with complexation was tested for radioactive wastes processing purpose. Sodium poly-acrylic acid was selected as the complexing agent, the efficiency of inorganic membrane with cut-off 1kD, 3kD, 8kD assisted by sodium poly-acrylic acid of different molecular weight were compared. The removal efficiencies of nuclides such as strontium, cesium and cobalt by were compared. The flux and retention factors of different membrane system were compared. The impacts of complexation agent concentration on permeate flux retention factors were studied. The long term behaviours of the membrane system were also studied. Diatomite filter was selected as the pretreatment method, and the efficiency of diatomite filter for pretreatment was investigated also. (author)

Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

Directory of Open Access Journals (Sweden)

V.H. Tournas

2009-01-01

Full Text Available Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF and the FDA official (BAM method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM counts similar to those of the BAM (reference method. Statistical analysis of the data (t-test revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

Development of new reference materials for the determination of cadmium, chromium, mercury and lead in polycarbonate

International Nuclear Information System (INIS)

Lee, Kil Jae; Lee, Yeo Jin; Choi, Young Rak; Kim, Jeong Sook; Kim, Youn Sung; Heo, Soo Bong

2013-01-01

Highlights: ► RMs for the determination of Cd, Cr, Hg and Pb in polycarbonate were developed. ► Double ID-ICP-MS technique was used for characterization of candidate RMs. ► The certified values for the elements ranged from 51.7 to 1133 mg kg −1 . ► The relative expanded uncertainties were shown to be less than 5.4%. ► New RMs were found to be suitable for the RoHS compliant tests. - Abstract: Reference materials for quantitative determination of Cd, Cr, Hg and Pb in polycarbonate were developed. Reference materials with two concentration level of elements were prepared by adding appropriate amounts of chemicals to a blank polycarbonate base material. It was shown that ten bottles with triplicate analysis are enough to demonstrate the homogeneity of these candidate reference materials. The statistical results also showed no significant trends in both short-term stability test for four weeks and long-term stability test for twelve months. The certification of the four elements was carried out by isotope-dilution-inductively coupled plasma mass spectrometry (ID-ICP-MS) with microwave-assisted digestion. Certification of candidate reference materials in a single laboratory was confirmed with interlaboratory comparison participated by a certain number of well-recognized testing laboratories in Korea. The certified values and expanded uncertainties (k = 2) for the candidate reference material with low level and the one with high level were (51.7 ± 2.1) mg kg −1 Cd, (103.8 ± 2.9) mg kg −1 Cd, (98.8 ± 4.5) mg kg −1 Cr, (1004 ± 49.8) mg kg −1 Cr, (107.4 ± 4.6) mg kg −1 Hg, (1133 ± 50.7) mg kg −1 Hg, (94.8 ± 3.7) mg kg −1 Pb and (988.4 ± 53.6) mg kg −1 Pb, respectively. The reference materials developed in this study demonstrated their suitability for the quality assurance in Cd, Cr, Hg and Pb analysis for the implementation of RoHS Directive.

Purification and differentiation of human adipose-derived stem cells by membrane filtration and membrane migration methods

Science.gov (United States)

Lin, Hong Reng; Heish, Chao-Wen; Liu, Cheng-Hui; Muduli, Saradaprasan; Li, Hsing-Fen; Higuchi, Akon; Kumar, S. Suresh; Alarfaj, Abdullah A.; Munusamy, Murugan A.; Hsu, Shih-Tien; Chen, Da-Chung; Benelli, Giovanni; Murugan, Kadarkarai; Cheng, Nai-Chen; Wang, Han-Chow; Wu, Gwo-Jang

2017-01-01

Human adipose-derived stem cells (hADSCs) are easily isolated from fat tissue without ethical concerns, but differ in purity, pluripotency, differentiation ability, and stem cell marker expression, depending on the isolation method. We isolated hADSCs from a primary fat tissue solution using: (1) conventional culture, (2) a membrane filtration method, (3) a membrane migration method where the primary cell solution was permeated through membranes, adhered hADSCs were cultured, and hADSCs migrated out from the membranes. Expression of mesenchymal stem cell markers and pluripotency genes, and osteogenic differentiation were compared for hADSCs isolated by different methods using nylon mesh filter membranes with pore sizes ranging from 11 to 80 μm. hADSCs isolated by the membrane migration method had the highest MSC surface marker expression and efficient differentiation into osteoblasts. Osteogenic differentiation ability of hADSCs and MSC surface marker expression were correlated, but osteogenic differentiation ability and pluripotent gene expression were not. PMID:28071738

Complementary theta resonance filtering by two spatially segregated mechanisms in CA1 hippocampal pyramidal neurons.

Science.gov (United States)

Hu, Hua; Vervaeke, Koen; Graham, Lyle J; Storm, Johan F

2009-11-18

Synaptic input to a neuron may undergo various filtering steps, both locally and during transmission to the soma. Using simultaneous whole-cell recordings from soma and apical dendrites from rat CA1 hippocampal pyramidal cells, and biophysically detailed modeling, we found two complementary resonance (bandpass) filters of subthreshold voltage signals. Both filters favor signals in the theta (3-12 Hz) frequency range, but have opposite location, direction, and voltage dependencies: (1) dendritic H-resonance, caused by h/HCN-channels, filters signals propagating from soma to dendrite when the membrane potential is close to rest; and (2) somatic M-resonance, caused by M/Kv7/KCNQ and persistent Na(+) (NaP) channels, filters signals propagating from dendrite to soma when the membrane potential approaches spike threshold. Hippocampal pyramidal cells participate in theta network oscillations during behavior, and we suggest that that these dual, polarized theta resonance mechanisms may convey voltage-dependent tuning of theta-mediated neural coding in the entorhinal/hippocampal system during locomotion, spatial navigation, memory, and sleep.

Low Loss Polycarbonate Polymer Optical Fiber for High Temperature FBG Humidity Sensing

DEFF Research Database (Denmark)

Woyessa, Getinet; Fasano, Andrea; Markos, Christos

2017-01-01

We report the fabrication and characterization of a polycarbonate (PC) microstructured polymer optical fiber (mPOF) Bragg grating (FBG) humidity sensor that can operate beyond 100°C. The PC preform, from which the fiber was drawn, was produced using an improved casting approach to reduce...... the attenuation of the fiber. The fiber loss was found reduced by a factor of two compared to the latest reported PC mPOF [20], holding the low loss record in PC based fibers. PC mPOFBG was characterized to humidity and temperature, and a relative humidity (RH) sensitivity of 7.31± 0.13 pm/% RH in the range 10...

Hard coatings by plasma CVD on polycarbonate for automotive and optical applications

International Nuclear Information System (INIS)

Schmauder, T.; Nauenburg, K.-D.; Kruse, K.; Ickes, G.

2006-01-01

In many applications, plastic surfaces need coatings as a protection against abrasion or weathering. Leybold Optics is developing Plasma CVD processes and machinery for transparent hard coatings (THC) for polycarbonate parts. In this paper we present the current features and remaining challenges of this technique. The coatings generally show excellent adhesion. Abrasion resistance is superior to commonly used lacquers. Climate durability of the coating has been improved to pass the tests demanded by automotive specifications. Current activities are focused on improving the durability under exposure to UV radiation. Estimations show that our high-rate plasma CVD hard coating process is also economically competitive to lacquering

Hydrolysis of polycarbonate in sub-critical water in fused silica capillary reactor with in situ Raman spectroscopy

Science.gov (United States)

Pan, Z.; Chou, I-Ming; Burruss, R.C.

2009-01-01

The advantages of using fused silica capillary reactor (FSCR) instead of conventional autoclave for studying chemical reactions at elevated pressure and temperature conditions were demonstrated in this study, including the allowance for visual observation under a microscope and in situ Raman spectroscopic characterization of polycarbonate and coexisting phases during hydrolysis in subcritical water.

The influence of organoclays on the morphology, phase separation and thermal properties of polycarbonate-based polyurethane hybrid materials

Czech Academy of Sciences Publication Activity Database

Pavličević, J.; Špírková, Milena; Sinadinović-Fišer, S.; Budinski-Simendic, J.; Govedarica, O.; Janković, M.

2013-01-01

Roč. 32, č. 1 (2013), s. 151-161 ISSN 1857-5552 R&D Projects: GA ČR GAP108/10/0195 Institutional support: RVO:61389013 Keywords : polycarbonate-based polyurethane * bentonite * montmorillonite Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.310, year: 2013 http://www.mjcce.org.mk/index.php/MJCCE/article/view/144

[Decontamination of dental unit waterlines using disinfectants and filters].

Science.gov (United States)

Monarca, S; Garusi, G; Gigola, P; Spampinato, L; Zani, C; Sapelli, P L

2002-10-01

Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

Filtering algorithm for radial displacement measurements of a dented pipe

International Nuclear Information System (INIS)

Hojjati, M.H.; Lukasiewicz, S.A.

2008-01-01

Experimental measurements are always affected by some noise and errors caused by inherent inaccuracies and deficiencies of the experimental techniques and measuring devices used. In some fields, such as strain calculations in a dented pipe, the results are very sensitive to the errors. This paper presents a filtering algorithm to remove noise and errors from experimental measurements of radial displacements of a dented pipe. The proposed filter eliminates the errors without harming the measured data. The filtered data can then be used to estimate membrane and bending strains. The method is very effective and easy to use and provides a helpful practical measure for inspection purposes

Membrane fouling mechanism transition in relation to feed water composition

KAUST Repository

Myat, Darli Theint

2014-12-01

The impact of secondary effluent wastewater from the Eastern Treatment Plant (ETP), Melbourne, Australia, before and after ion exchange (IX) treatment and polyaluminium chlorohydrate (PACl) coagulation, on hydrophobic polypropylene (PP) and hydrophilic polyvinylidene fluoride (PVDF) membrane fouling was studied. Laboratory fouling tests were operated over 3-5 days with regular, intermittent backwash. During the filtration with PP membranes, organic rejection data indicated that humic adsorption on hydrophobic PP membrane occurred during the first 24h of filtration and contributed to fouling for both raw wastewater and pre-treated wastewaters. However, after the first 24h of filtration the contribution of humic substances to fouling diminished and biopolymers that contribute to cake layer development became more prominent in their contribution to the fouling rate. For PVDF membranes, the per cent removal of humic substances from both raw wastewater and pre-treated wastewaters was very small as indicated by no change in UV254 from the feed to the permeate over the filtration period, even during the early stages of filtration. This suggested that the hydrophobic PP membrane adsorbed humic substances while the hydrophilic PVDF membrane did not. The highest mass of biopolymer removal by each PVDF membrane was from ETP water followed by PACl and IX treated water respectively. This was possibly due to differences in the backwashing efficiency linked to the filter cake contributed by biopolymers. Hydraulic backwashing was more effective during the later stages of filtration for the ETP water compared to IX and PACl treated waters, indicating that the filter cake contributed by ETP biopolymers was more extensively removed by hydraulic backwashing. It was proposed that humic substances may act to stabilise biopolymers in solution and that removing humics substances by coagulation or IX results in greater adhesive forces between the biopolymers and membrane/filter cake

The determination of the pore distribution and the consideration of methods leading to the prediction of retention characteristics of membrane filters

International Nuclear Information System (INIS)

Badenhop, C.T.

1983-01-01

Presented here is a method for the determination of the pore size distribution of a membrane microfilter. Existing test metods are either cumbersome, as is the Erbe method; time consuming, as is the evaluation of electron microscope photographs; do not really measure the pore distribution, as the mercury intrusion method; or do not satisfactorily evaluate the large pore range of the filter, as is the case with the automated ASTM method. The new method described in this paper is based upon the solution of the integral flow equation for the pore distribution function. A computer program evaluates the flow test data and calculates the numerical pore distribution, water-flow distribution, air-flow distribution and capillary area distribution, as a function of the pore size. (orig./RW)

Estimation of Water Diffusion Coefficient into Polycarbonate at Different Temperatures Using Numerical Simulation

DEFF Research Database (Denmark)

Shojaee Nasirabadi, Parizad; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2016-01-01

) is widely used in the electronics industry. Thus, in this work the water diffusion coefficient into PC is investigated. Furthermore, numerical methods used for estimation of the diffusion coefficient and their assumptions are discussed. 1D and 3D numerical solutions are compared and based on this, itis......Nowadays, many electronic systems are exposed to harsh conditions of relative humidity and temperature. Masstransport properties of electronic packaging materials are needed in order to investigate the influence of moisture andtemperature on reliability of electronic devices. Polycarbonate (PC...... shown how the estimated value can be different depending on the choice of dimensionality in the model....

Fundamental and Applied Studies of Polymer Membranes

Science.gov (United States)

Imbrogno, Joseph

Four major areas have been studied in this research: 1) synthesizing novel monomers, e.g. chiral monomers, to produce new types of functionalized membranes for the biotechnology and pharmaceutical industries, 2) hydrophobic brush membranes for desalinating brackish water, sea water, and separating organics, 3) fundamental studies of water interactions at surfaces using sum frequency generation (SFG), and 4) discovering new surface chemistries that will control the growth and differentiation of stem cells. We have developed a novel synthesis method in order to increase the breadth of our high throughput screening library. This library was generated using maleimide chemistry to react a common methacrylate linker with a variety of different functions groups (R groups) in order to form new monomers that were grafted from the surface of PES ultrafiltration membranes. From this work, we discovered that the chirality of a membrane can affect performance when separating chiral feed streams. This effect was observed when filtering bovine serum albumin (BSA) and ovalbumin in a high salt phosphate buffered saline (PBS, 150 mM salt). The Phe grafted membranes showed a large difference in performance when filtering BSA with selectivity of 1.13 and 1.00 for (S) and (R) Phe, respectively. However, when filtering ovalbumin, the (S) and (R) modified surfaces showed selectivity of 2.06 and 2.31, respectively. The higher selectivity enantiomer switched for the two different proteins. Permeability when filtering BSA was 3.06 LMH kPa-1 and 4.31 LMH kPa -1 for (S)- and (R)- Phe, respectively, and 2.65 LMH kPa -1 and 2.10 LMH kPa-1 when filtering ovalbumin for (S)- and (R)- Phe, respectively. Additionally, these effects were no longer present when using a low salt phosphate buffer (PB, 10 mM salt). Since, to our knowledge, membrane chirality is not considered in current industrial systems, this discovery could have a large impact on the pharmaceutical and biotechnology industries. We

Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors

DEFF Research Database (Denmark)

Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol

2016-01-01

Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C...

Membrane filtration device for studying compression of fouling layers in membrane bioreactors.

Directory of Open Access Journals (Sweden)

Mads Koustrup Jørgensen

Full Text Available A filtration devise was developed to assess compressibility of fouling layers in membrane bioreactors. The system consists of a flat sheet membrane with air scouring operated at constant transmembrane pressure to assess the influence of pressure on resistance of fouling layers. By fitting a mathematical model, three model parameters were obtained; a back transport parameter describing the kinetics of fouling layer formation, a specific fouling layer resistance, and a compressibility parameter. This stands out from other on-site filterability tests as model parameters to simulate filtration performance are obtained together with a characterization of compressibility. Tests on membrane bioreactor sludge showed high reproducibility. The methodology's ability to assess compressibility was tested by filtrations of sludges from membrane bioreactors and conventional activated sludge wastewater treatment plants from three different sites. These proved that membrane bioreactor sludge showed higher compressibility than conventional activated sludge. In addition, detailed information on the underlying mechanisms of the difference in fouling propensity were obtained, as conventional activated sludge showed slower fouling formation, lower specific resistance and lower compressibility of fouling layers, which is explained by a higher degree of flocculation.

In Situ Cleanable Alternative HEPA Filter Media

International Nuclear Information System (INIS)

Adamson, D. J.; Terry, M. T.

2002-01-01

The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the Department of

UV Induced Degradation of Polycarbonate-Based Lens Materials and Implications for the Heath Care Field

Science.gov (United States)

Harkay, J. R.; Henry, Jerry

2006-10-01

Experimental research is being carried out at Keene State at the undergraduate level that utilizes facilities in both physics and chemistry to study the effects of mono- and polychromatic UV radiation from various sources, including a Deuterium lamp, a solarization unit (at Polyonics, a local industry), and the Sun, to study the photodegradation of polycarbonate-based lens materials used to produce eyewear. Literature in the field of optometry and ophthalmology indicates a correlation between exposure to the UVB band of natural sunlight and the onset of cataract formation, as well as other eye disorders. The public is usually advised that plastic eyeglass lenses will provide protection from this damaging radiation. It is well known that polycarbonate plastic ``yellows'' when exposed to intense sunlight and, particularly, UV light^1,2, either via photo-Fries rearrangement or by a photooxidative process, forming polyconjugated systems and is an industrial concern primarily for cosmetic reasons. We have preliminary data, however, that indicates that the yellowing'' is an indication of a more sinister problem in the case of eyeglasses in that it is accompanied by an increase in transmissivity in the UVB band where the wearer expects and needs protection. Our group includes a local optometrist who will share results with peers in his field. [1] A. Andrady, J. Polymer Sci., 42, 1991 [2] E. P. Gorelov, Inst. Khim. Fiz., Russian Federation

Fluorinated copper-phthalocyanine-based n-type organic field-effect transistors with a polycarbonate gate insulator

International Nuclear Information System (INIS)

Sethuraman, Kunjithapatham; Kumar, Palanisamy; Santhakumar, Kannappan; Ochiai, Shizuyasu; Shin, Paikkyun

2012-01-01

Fluorinated copper-phthalocyanine (F 16 CuPc) thin films were prepared by using a vacuum evaporation technique and were applied to n-type organic field-effect transistors (OFETs) as active channel layers combined with a spin-coated polycarbonate thin-film gate insulator. The output characteristics of the resulting n-type OFET devices with bottom-gate/bottom-contact structures were investigated to evaluate the performances such as the field effect mobility (μ FE ), the on/off current ratio (I on/off ), and the threshold voltage (V th ). A relatively high field effect mobility of 6.0 x 10 -3 cm 2 /Vs was obtained for the n-type semiconductor under atmospheric conditions with an on/off current ratio of 1 x 10 4 and a threshold voltage of 5 V. The electron mobility of the n-type semiconductor was found to depend strongly on the growth temperature of the F 16 CuPc thin films. X-ray diffraction profiles showed that the crystallinity and the orientation of the F 16 CuPc on a polycarbonate thin film were enhanced with increasing growth temperature. Atomic force microscopy studies revealed various surface morphologies of the active layer. The field effect mobility of the F 16 CuPc-OFET was closely related to the crystallinity and the orientation of the F 16 CuPc thin film.

Attractive mechanical properties of a lightweight highly sensitive bi layer thermistor: polycarbonate/organic molecular conductor

International Nuclear Information System (INIS)

Laukhina, E; Lebedev, V; Rovira, C; Laukhin, V; Veciana, J

2016-01-01

The paper covers some of the basic mechanical characteristics of a recently developed bi layer thermistor: polycarbonate/(001) oriented layer of organic molecular conductor α’-(BEDT-TTF) 2 I x Br 3-x , were BEDT-TTF=bis(ethylenedithio)tetrathiafulvalen. The nano and macro mechanical properties have been studied in order to use this flexible, low cost thermistor in sensing applications by proper way. The nano-mechanical properties of the temperature sensitive semiconducting layer of α’-(BEDT-TTF) 2 I x Br 3-x were tested using nanoindentation method. The value of Young's modulus in direction being perpendicular to the layer plan was found as 9.0 ±1.4 GPa. The macro mechanical properties of the thermistor were studied using a 5848 MicroTester. The tensile tests showed that basic mechanical characteristics of the thermistor are close to those of polycarbonate films. This indicates a good mechanical strength of the developed sensor. Therefore, the thermistor can be used in technologies that need to be instrumented with highly robustness lightweight low cost temperature sensors. The paper also reports synthetic details on fabricating temperature sensing e-textile. As the temperature control is becoming more and more important in biomedical technologies like healthcare monitoring, this work strongly contributes on the ongoing research on engineering sensitive conducting materials for biomedical applications. (paper)

Mechanical and thermomechanical properties of polycarbonate-based polyurethane-silica nanocomposites

Directory of Open Access Journals (Sweden)

Rafał Poręba

2011-09-01

Full Text Available In this work aliphatic polycarbonate-based polyurethane-silica nanocomposites were synthesized and characterized. The influence of the type and of the concentration of nanofiller differing in average particle size (7 nm for Aerosil 380 and 40 nm for Nanosilica 999 on mechanical and thermomechanical properties was investigated. DMTA measurements showed that Nanosilica 999, irrespective of its concentration, slightly increased the value of the storage shear modulus G’ but Aerosil 380 brings about a nearly opposite effect, the shear modulus in the rubber region decreases with increasing filler content. Very high elongations at break ranging from 800% to more than 1000%, as well as high tensile strengths illustrate excellent ultimate tensile properties of the prepared samples. The best mechanical and thermomechanical properties were found for the sample filled with 0.5 wt.% of Nanosilica 999.

Mitigating leaks in membranes

Energy Technology Data Exchange (ETDEWEB)

Karnik, Rohit N.; Bose, Suman; Boutilier, Michael S.H.; Hadjiconstantinou, Nicolas G.; Jain, Tarun Kumar; O' Hern, Sean C.; Laoui, Tahar; Atieh, Muataz A.; Jang, Doojoon

2018-02-27

Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

Silica incorporated membrane for wastewater based filtration

Science.gov (United States)

Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

2017-10-01

Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

Superwetting nanowire membranes for selective absorption.

Science.gov (United States)

Yuan, Jikang; Liu, Xiaogang; Akbulut, Ozge; Hu, Junqing; Suib, Steven L; Kong, Jing; Stellacci, Francesco

2008-06-01

The construction of nanoporous membranes is of great technological importance for various applications, including catalyst supports, filters for biomolecule purification, environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here we present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behaviour ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's weight in preference to water, through a combination of superhydrophobicity and capillary action. Moreover, the nanowires that form the membrane structure can be re-suspended in solutions and subsequently re-form the original paper-like morphology over many cycles. Our results suggest an innovative material that should find practical applications in the removal of organics, particularly in the field of oil spill cleanup.

Improved antifouling potential of polyether sulfone polymeric membrane containing silver nanoparticles: self-cleaning membranes.

Science.gov (United States)

Rana, Sidra; Nazar, Umair; Ali, Jafar; Ali, Qurat Ul Ain; Ahmad, Nasir M; Sarwar, Fiza; Waseem, Hassan; Jamil, Syed Umair Ullah

2018-06-01

A new strategy to enhance the antifouling potential of polyether sulfone (PES) membrane is presented. Chemically synthesized silver nanoparticles (AgNPs) were used to prepare a mixed-matrix PES membrane by the phase inversion technique. Primarily, AgNPs synthesis was confirmed by surface plasmon resonance at 410-430 nm using UV-Visible spectroscopy. X-ray diffraction analysis revealed that AgNPs were crystalline with a diameter of 21 ± 2 nm. Furthermore, PES membranes were characterized by energy dispersive X-ray spectroscopy to confirm the incorporation of AgNPs in membranes. Hydrophilicity of the membranes was enhanced, whereas roughness, mechanical strength and biofouling were relatively reduced after embedding the AgNPs. Antibacterial potential of AgNPs was evaluated for E. coli in the disc diffusion and colony-forming unit (CFU) count method. All of the membranes were assessed for antifouling activity by filtering a control dilution (10 6  CFU/ml) of E. coli and by counting CFU. Anti-biofouling activity of the membrane was observed with different concentrations of AgNPs. Maximum reduction (66%) was observed in membrane containing 1.5% of AgNPs. The addition of antibiotic ceftriaxone enhanced the antibacterial effect of AgNPs in PES membranes. Our practicable antifouling strategy may be applied to other polymeric membranes which may pave the new way to achieve sustainable and self-cleaning membrane reactors on large scale.

Template Synthesis of Nanostructured Polymeric Membranes by Inkjet Printing.

Science.gov (United States)

Gao, Peng; Hunter, Aaron; Benavides, Sherwood; Summe, Mark J; Gao, Feng; Phillip, William A

2016-02-10

The fabrication of functional nanomaterials with complex structures has been serving great scientific and practical interests, but current fabrication and patterning methods are generally costly and laborious. Here, we introduce a versatile, reliable, and rapid method for fabricating nanostructured polymeric materials. The novel method is based on a combination of inkjet printing and template synthesis, and its utility and advantages in the fabrication of polymeric nanomaterials is demonstrated through three examples: the generation of polymeric nanotubes, nanowires, and thin films. Layer-by-layer-assembled nanotubes can be synthesized in a polycarbonate track-etched (PCTE) membrane by printing poly(allylamine hydrochloride) and poly(styrenesulfonate) sequentially. This sequential deposition of polyelectrolyte ink enables control over the surface charge within the nanotubes. By a simple change of the printing conditions, polymeric nanotubes or nanowires were prepared by printing poly(vinyl alcohol) in a PCTE template. In this case, the high-throughput nature of the method enables functional nanomaterials to be generated in under 3 min. Furthermore, we demonstrate that inkjet printing paired with template synthesis can be used to generate patterns comprised of chemically distinct nanomaterials. Thin polymeric films of layer-by-layer-assembled poly(allylamine hydrochloride) and poly(styrenesulfonate) are printed on a PCTE membrane. Track-etched membranes covered with the deposited thin films reject ions and can potentially be utilized as nanofiltration membranes. When the fabrication of these different classes of nanostructured materials is demonstrated, the advantages of pairing template synthesis with inkjet printing, which include fast and reliable deposition, judicious use of the deposited materials, and the ability to design chemically patterned surfaces, are highlighted.

Filterability of membrane bioreactor (MBR) sludge: impacts of polyelectrolytes and mixing with conventional activated sludge.

Science.gov (United States)

Yigit, Nevzat O; Civelekoglu, Gokhan; Cinar, Ozer; Kitis, Mehmet

2010-01-01

The main objective of this work was to investigate the filterability of MBR sludge and its mixture with conventional activated sludge (CAS). In addition, the impacts of type and dose of various polyelectrolytes, filter type and sludge properties on the filterability of both MBR and Mixed sludges were determined. Specific cake resistance (SCR) measured by the Buchner funnel filtration test apparatus and the solids content of the resulting sludge cake were used to assess the dewaterability of tested sludges. The type of filter paper used in Buchner tests affected the results of filterability for MBR, CAS and Mixed sludges. SCR values and optimum polyelectrolyte doses increased with increasing MLSS concentrations in the MBR, which suggested that increase in MLSS concentrations accompanied by increases in EPS and SMP concentrations and a shift toward smaller particles caused poorer dewaterability of the MBR sludge. The significant differences observed among the filterability of CAS and MBR sludges suggested that MLSS alone is not a good predictor of sludge dewaterability. Combining CAS and MBR sludges at different proportions generally improved their dewaterability. Combining MBR sludges having typically high MLSS and EPS concentrations with CAS having much lower MLSS concentrations may be an option for full-scale treatment plants experiencing sludge dewaterability problems. Better filterability and higher cake dry solids were achieved with cationic polyelectrolytes compared to anionic and non-ionic ones for all sludge types tested.

Multilayer models of photosynthetic membranes. Final report

Energy Technology Data Exchange (ETDEWEB)

Brocklehurst, J R; Flanagan, M T

1982-01-01

The primary aim of this project has been to build an artificial membrane in which is incorporated, in a functional state, the protein bacteriorhodopsin responsible for generating an electrical potential difference across the membrane of the photosynthetic bacterium, halobacterium halobium, and to investigate the use of this artificial system as the basis of a solar cell. the bacteriorhodopsin has been incorporated into Langmuir-Blodgett multilayers. If ths supporting filter is then illuminated, a potential difference is generated between the two compartments. The lipid in the filter appears to act as a charge carrier for protons, the charge species that forms the electrochemical gradient generated by the bacteriorhodopsin when this molecule absorbs light. The internal resistances of such solar cells were determined and found to be so high that the cells could not be seriously considered as competitors with classical semiconductor cells. Multilayerswere deposited onto filters in which ion carriers that make the filters permeable to sodium ions had been dissolved in the paraffin. The photovoltage obtained indicated that protons transferred from one side of the filter to the other by the action of the bacteriorhodopsin were bing exchanged for sodium ions. A secondary aim of the project has been to examine the possibility of depositing mixed multilayers of a dye and a long chain quinone onto a semiconductor surface. A sensitizing multilayer has been prepared and the mobility of long chain quinones within the layers is high enough to warrant further research. However, it was found that, with the dyes and quinones used, quenched complexes were formed which would not act as sensitizers.

Performance of diatomite/iron oxide modified nonwoven membrane used in membrane bioreactor process for wastewater reclamation.

Science.gov (United States)

He, Yueling; Zhang, Wenqi; Rao, Pinhua; Jin, Peng

2014-01-01

This study describes an approach for surface modification of a nonwoven membrane by diatomite/iron oxide to examine its filterability. Analysis results showed that nonwoven hydrophilicity is enhanced. Static contact angle decreases dramatically from 122.66° to 39.33°. Scanning electron micrograph images show that diatomite/iron oxide is attached on nonwoven fiber. X-ray diffraction analysis further proves that the compound is mostly magnetite. Fourier transformed infrared spectra results reveal that two new absorption peaks might be attributed to Si-O and Fe-O, respectively. Modified and original membranes were used in double nonwoven membrane bioreactors (MBRs) for synthetic wastewater treatment. High critical flux, long filtration time, slow trans-membrane pressure rise and stable sludge volume index confirmed the advantages of modified nonwoven. Comparing with original nonwoven, similar effluent qualities are achieved, meeting the requirements for wastewater reclamation.

Application for airborne particulate matter as a demonstration using k0-NAA method in Dalat nuclear research institute of Vietnam

International Nuclear Information System (INIS)

Ho Manh Dung; Cao Dong Vu; Nguyen Thi Sy; Truong Y; Nguyen Thanh Binh

2004-01-01

The airborne particulate samples have been collected using two types of polycarbonate membrane filter PM 2.5 and PM 2-5-10 in two typical sites of industrial (Ho Chi Minh City) and rural (Dateh) regions in south of Vietnam. The concentration of trace elements in the samples has been determined by the k 0 -NAA procedure developed in Dalat NRI. In order to check the developed k 0 -NAA procedure for the airborne particulate matter, two standard reference materials (SRMs) Urban Particulate NIST-1648 and Vehicle Exhaust Particulates NIES-8 were analyzed and the obtained results have been compared and interpreted in term of deviation between experimental results and the certified values. (author)

Selection of filter media in alpha air monitors for emergency environmental monitoring

International Nuclear Information System (INIS)

Kinouchi, N.; Oishi, T.; Noguchi, H.; Kato, S.

2000-01-01

We have developed an alpha air monitor which is possible to measure rapidly and sensitively the concentrations of airborne alpha-emitting particles, such as plutonium, for the environmental monitoring at an accident of nuclear reprocessing plant. The monitor is designed to collect airborne alpha-emitting particles by drawing the ambient air through a filter and to detect the activity by alpha spectroscopy. In order to achieve high-sensitive measurements, selection of a suitable filter used in the monitor is considerably important. The most important requirement for the filter is that it has a high surface collection efficiency to obtain the sharpness of the alpha energy spectrum. This makes it easy to distinguish the alpha-ray peak of plutonium from the alpha spectrum of naturally occurring radon decay products in the environment. And the filter is also desired to have low resistance of the air flow so that particles can be collected at a high flowrate. We have made a comparison of the surface collection efficiency and pressure drop for the various filters. Types of the test filters, most of which are commercially available in Japan, were glass fiber, cellulose-glass fiber, membrane and so on. The surface collection efficiency has been evaluated by the following two indices. One was the sharpness of alpha-ray energy peaks of thoron decay products generated in a laboratory and collected in the fibers. The other was the background counts of radon decay products in a plutonium region by measuring alpha-ray energy spectrum of radon decay products collected in the filters by sampling of dust in the atmosphere. It was found that the PTFE (polytetrafluoroethylene) membrane filter with backing had a high surface collection efficiency and low pressure drop. The results of the test are described in detail in this paper. (author)

Seasonal Variation of Atmospheric Composition of Water-Soluble ...

African Journals Online (AJOL)

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and 2006 wet season campaigns using a “Gent” PM10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters. ... the effectiveness of abatement strategies for relevant ..... Giri, D., V.K. Murthy, P.R. Adhikary, and. S.N. Khanal ...

Practical Gammatone-Like Filters for Auditory Processing

Directory of Open Access Journals (Sweden)

R. F. Lyon

2007-12-01

Full Text Available This paper deals with continuous-time filter transfer functions that resemble tuning curves at particular set of places on the basilar membrane of the biological cochlea and that are suitable for practical VLSI implementations. The resulting filters can be used in a filterbank architecture to realize cochlea implants or auditory processors of increased biorealism. To put the reader into context, the paper starts with a short review on the gammatone filter and then exposes two of its variants, namely, the differentiated all-pole gammatone filter (DAPGF and one-zero gammatone filter (OZGF, filter responses that provide a robust foundation for modeling cochlea transfer functions. The DAPGF and OZGF responses are attractive because they exhibit certain characteristics suitable for modeling a variety of auditory data: level-dependent gain, linear tail for frequencies well below the center frequency, asymmetry, and so forth. In addition, their form suggests their implementation by means of cascades of N identical two-pole systems which render them as excellent candidates for efficient analog or digital VLSI realizations. We provide results that shed light on their characteristics and attributes and which can also serve as “design curves” for fitting these responses to frequency-domain physiological data. The DAPGF and OZGF responses are essentially a “missing link” between physiological, electrical, and mechanical models for auditory filtering.

Rapid monitoring particulate radiocesium with nonwoven fabric cartridge filter and application to field monitoring

International Nuclear Information System (INIS)

Tsuji, Hideki; Yasutaka, Tetsuo; Kondo, Yoshihiko; Kawashima, Shoji

2013-01-01

A method for rapid monitoring particulate radiocesium using a nonwoven fabric cartridge filter was developed, which needs no further preprocessing before served to a detector. By a performance test, more than 98% of suspended solid (SS) was collected. This method showed the same radioactivity measurement accuracy as filtration by membrane filter and more rapid extraction capability of SS. (author)

Development of Polyvinylidene fluoride (PVDF)-ZIF-8 Membrane for Wastewater Treatment

Science.gov (United States)

Ibrahim, N. A.; Wirzal, M. D. H.; Nordin, N. A. H.; Halim, N. S. Abd

2018-04-01

Nowadays, the water shortage problem following the urbanization and increasing pollution of natural water source have increased the awareness to treat wastewater. Membrane filtration is often used in wastewater treatment plants to filter out more residual activated sludge from aeration process in the secondary stage. However, fouling is the main concern due to the fact it can happen to any membrane application. Antifouling properties in membrane can be improved by blending membranes with fillers or additives to make them more hydrophilic. This study aims to improve the antifouling properties in polyvinylidene fluoride (PVDF) membranes while optimizing the loading of Zeolitic imidazolate framework-8 (ZIF-8) fillers; at different loading (2.0 wt. %, 4.0 wt. %, 6.0 wt. %, 8.0 wt. % and 10.0 wt. %). Manual hand-casting of flat sheet membrane was done and the fabricated membranes were tested for their filterability against pure water and domestic wastewater. Both permeability tests showed that PVDF with 8% ZIF-8 membrane was the most permeable with a pure water and wastewater permeability of 150 L/m2.h.bar and 94 L/m2.h.bar, respectively. The pure water permeability of PVDF with 8% ZIF-8 membrane increases for about 130% compared to the pure PVDF membrane. The turbidity test of the initial feed and final permeate of wastewater, PVDF with 8% ZIF-8 membrane also gave out the highest reduction rate at 87%, which is 36% higher than that of pure PVDF membrane. It can be deduced that 8% of ZIF-8 is the ideal loading to PVDF in improving its antifouling properties to be used in domestic wastewater treatment.

Grafting of phosphorylcholine functional groups on polycarbonate urethane surface for resisting platelet adhesion

Energy Technology Data Exchange (ETDEWEB)

Gao, Bin [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Lu, Jian; Zhang, Li; Zhao, Miao; Shi, Changcan; Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

2013-07-01

In order to improve the resistance of platelet adhesion on material surface, 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted onto polycarbonate urethane (PCU) surface via Michael reaction to create biomimetic structure. After introducing primary amine groups via coupling tris(2-aminoethyl)amine (TAEA) onto the polymer surface, the double bond of MPC reacted with the amino group to obtain MPC modified PCU. The modified surface was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results verified that MPC was grafted onto PCU surface by Michael reaction method. The MPC grafted PCU surface had a low water contact angle and a high water uptake. This means that the hydrophilic PC functional groups improved the surface hydrophilicity significantly. In addition, surface morphology of MPC grafted PCU film was imaged by atomic force microscope (AFM). The results showed that the grafted surface was rougher than the blank PCU surface. In addition, platelet adhesion study was evaluated by scanning electron microscopy (SEM) observation. The PCU films after treated with platelet-rich plasma demonstrated that much fewer platelets adhered to the MPC-grafted PCU surface than to the blank PCU surface. The antithrombogenicity of the MPC-grafted PCU surface was determined by the activated partial thromboplastin time (APTT). The result suggested that the MPC modified PCU may have potential application as biomaterials in blood-contacting and some subcutaneously implanted devices. - Highlights: • MPC was successfully grafted onto polycarbonate urethane surface via Michael reaction. • High concentration of PC functional groups on the surface via TAEA molecule • Biomimetic surface modification • The modified surface showed high hydrophilicity and anti-platelet adhesion.

Transport of Carbon Dioxide through a Biomimetic Membrane

Directory of Open Access Journals (Sweden)

Efstathios Matsaridis

2011-01-01

Full Text Available Biomimetic membranes (BMM based on polymer filters impregnated with lipids or their analogues are widely applied in numerous areas of physics, biology, and medicine. In this paper we report the design and testing of an electrochemical system, which allows the investigation of CO2 transport through natural membranes such as alveoli barrier membrane system and also can be applied for solid-state measurements. The experimental setup comprises a specially designed two-compartment cell with BMM connected with an electrochemical workstation placed in a Faraday cage, two PH meters, and a nondispersive infrared gas analyzer. We prove, experimentally, that the CO2 transport through the natural membranes under different conditions depends on pH and displays a similar behavior as natural membranes. The influence of different drugs on the CO2 transport process through such membranes is discussed.

Freestanding membrane composed of micro-ring array with ultrahigh sidewall aspect ratio for application in lightweight cathode arrays

Science.gov (United States)

Wang, Lanlan; Liu, Hongzhong; Jiang, Weitao; Gao, Wei; Chen, Bangdao; Li, Xin; Ding, Yucheng; An, Ningli

2014-12-01

A freestanding multilayer ultrathin nano-membrane (FUN-membrane) with a micro-ring array (MRA) is successfully fabricated through the controllable film deposition. Each micro-ring of FUN-membrane is 3 μm in diameter, 2 μm in height and sub-100 nm in sidewall thickness, demonstrating an ultrahigh sidewall aspect ratio of 20:1. In our strategy, a silica layer (200 nm in thickness), a chromium transition layer (5 nm-thick) and a gold layer (40 nm-thick), were in sequence deposited on patterned photoresist. After removal of the photoresist by lift-off process, a FUN-membrane with MRA was peeled off from the substrate, where the gold layer acted as a protecting layer to prevent the MRA from fracture. The FUN-membrane was then transferred to a flexible polycarbonate (PC) sheet coated with indium tin oxide (ITO) layer, which was then used as a flexible and lightweight cathode. Remarkably, the field emission effect of the fabricated FUN-membrane cathode performs a high field-enhancement factor of 1.2 × 104 and a low turn-on voltage of 2 V/μm, indicating the advantages of the sharp metal edge of MRA. Due to the rational design and material versatility, the FUN-membrane thus could be transferred to either rigid or flexible substrate, even curved surface, such as the skin of bio-robot's arm or leg. Additionally, the FUN-membrane composed of MRA with extremely high aspect ratio of insulator-metal sidewall, also provides potential applications in optical devices, lightweight and flexible display devices, and electronic eye imagers.

Self-assembled magnetic filter for highly efficient immunomagnetic separation.

Science.gov (United States)

Issadore, David; Shao, Huilin; Chung, Jaehoon; Newton, Andita; Pittet, Mikael; Weissleder, Ralph; Lee, Hakho

2011-01-07

We have developed a compact and inexpensive microfluidic chip, the self-assembled magnetic filter, to efficiently remove magnetically tagged cells from suspension. The self-assembled magnetic filter consists of a microfluidic channel built directly above a self-assembled NdFeB magnet. Micrometre-sized grains of NdFeB assemble to form alternating magnetic dipoles, creating a magnetic field with a very strong magnitude B (from the material) and field gradient ▽B (from the configuration) in the microfluidic channel. The magnetic force imparted on magnetic beads is measured to be comparable to state-of-the-art microfabricated magnets, allowing for efficient separations to be performed in a compact, simple device. The efficiency of the magnetic filter is characterized by sorting non-magnetic (polystyrene) beads from magnetic beads (iron oxide). The filter enriches the population of non-magnetic beads to magnetic beads by a factor of >10(5) with a recovery rate of 90% at 1 mL h(-1). The utility of the magnetic filter is demonstrated with a microfluidic device that sorts tumor cells from leukocytes using negative immunomagnetic selection, and concentrates the tumor cells on an integrated membrane filter for optical detection.

Thermal degradation kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane composite

Institute of Scientific and Technical Information of China (English)

Jiangbo WANG; Zhong XIN

2009-01-01

The thermal degradation behaviors of poly-carbonate/polymethylphenylsilsesquioxane (FRPC) composites were investigated by thermogravimetric analysis (TGA) under isothermal conditions in nitrogen atmosphere. The isothermal kinetics equation was used to describe the thermal degradation process. The results showed that activation energy (E), in the case of isothermal degradation, was a quick increasing function of conversion (a) for polycarbonate (PC) but was a strong and decreasing function of conversion for FRPC. Under the isothermal condition, the addition of polymethylphenylsilsesquioxane (PMPSQ) retardanted the thermal degradation and enhanced the thermal stability of PC during the early and middle stages of thermal degradation. It also indicated a possible existence of a difference in nucleation, nuclei growth, and gas diffusion mechanism in the thermal degradation process between PC and FRPC. Meanwhile, the addition of PMPSQ influenced the lifetime of PC, but the composite still met the demand in manufacturing and application.

Estimation of water diffusion coefficient into polycarbonate at different temperatures using numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Nasirabadi, P. Shojaee; Jabbari, M.; Hattel, J. H. [Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs. Lyngby (Denmark)

2016-06-08

Nowadays, many electronic systems are exposed to harsh conditions of relative humidity and temperature. Mass transport properties of electronic packaging materials are needed in order to investigate the influence of moisture and temperature on reliability of electronic devices. Polycarbonate (PC) is widely used in the electronics industry. Thus, in this work the water diffusion coefficient into PC is investigated. Furthermore, numerical methods used for estimation of the diffusion coefficient and their assumptions are discussed. 1D and 3D numerical solutions are compared and based on this, it is shown how the estimated value can be different depending on the choice of dimensionality in the model.

Fabrication of multilayer nanowires

Energy Technology Data Exchange (ETDEWEB)

Kaur, Jasveer, E-mail: kaurjasveer89@gmail.com; Singh, Avtar; Kumar, Davinder [Department of Physics, Punjabi University Patiala, 147002, Punjab (India); Thakur, Anup; Kaur, Raminder, E-mail: raminder-k-saini@yahoo.com [Department of Basic and Applied Sciences, Punjabi University Patiala, 147002, Punjab (India)

2016-05-06

Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.

Fabrication of multilayer nanowires

International Nuclear Information System (INIS)

Kaur, Jasveer; Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

2016-01-01

Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.

Nanofiltration of Mine Water: Impact of Feed pH and Membrane Charge on Resource Recovery and Water Discharge

Directory of Open Access Journals (Sweden)

Mark Mullett

2014-03-01

Full Text Available Two nanofiltration membranes, a Dow NF 270 polyamide thin film and a TriSep TS 80 polyamide thin film, were investigated for their retention of ionic species when filtering mine influenced water streams at a range of acidic pH values. The functional iso-electric point of the membranes, characterized by changes in retention over a small pH range, were examined by filtering solutions of sodium sulphate. Both membranes showed changes in retention at pH 3, suggesting a zero net charge on the membranes at this pH. Copper mine drainage and synthetic solutions of mine influenced water were filtered using the same membranes. These solutions were characterized by pH values within 2 and 5, thus crossing the iso-electric point of both membranes. Retention of cations was maximized when the feed solution pH was less than the iso-electric point of the membrane. In these conditions, the membrane has a net positive charge, reducing the transmission rate of cations. From the recoveries of a range of cations, the suitability of nanofiltration was discussed relative to the compliance with mine water discharge criteria and the recovery of valuable commodity metals. The nanofiltration process was demonstrated to offer advantages in metal recovery from mine waste streams, concomitantly enabling discharge criteria for the filtrate disposal to be met.

Novel fabrication method of the peritoneal dialysis filter using silk fibroin with urease fixation system.

Science.gov (United States)

Moon, Bo Mi; Choi, Myung-Jin; Sultan, Md Tipu; Yang, Jae Won; Ju, Hyung Woo; Lee, Jung Min; Park, Hyun Jung; Park, Ye Ri; Kim, Soo Hyeon; Kim, Dong Wook; Lee, Min Chae; Jeong, Ju Yeon; Lee, Ok Joo; Sung, Gun Yong; Park, Chan Hum

2017-10-01

During the last decade, there has been a great advance in the kidney dialysis system by wearable artificial kidney (WAK) system for end-stage renal disease patients. Uremic solute removal and water regeneration system are the most prerequisite for WAK to work properly. In this study, we designed a filtering membrane system by using immobilized urease silk fibroin filter and evaluated its comparative effectiveness with a PVDF filtering system in peritoneal dialysate regeneration system by urea removal efficacy. We evaluated this membrane's characteristic and performances by conducting SEM-EDX analyze, water-binding abilities and porosity test, removal abilities of urea, cytotoxicity assay and enzyme activity assay. Under the condition for optimization of urease, the percentage removal of urea was about 40% and 60% in 50 mg/dL urea solution by urease immobilized PVDF and silk fibroin scaffolds, respectively. The batch experimental result showed that immobilized filter removed more than 50% of urea in 50 mg/dL urea solution. In addition silk fibroin with urease filter removed 90 percent of urea in the peritoneal dialysate after 24 h filtration. We suggest that silk fibroin with urease fixation filter can be used more effectively for peritoneal dialysate regeneration system, which have hydrophilic property and prolonged enzyme activity. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2136-2144, 2017. © 2016 Wiley Periodicals, Inc.

Benchmarking of Sterilizing grade filters with liposome Filtration.

Science.gov (United States)

Loewe, Thomas; Mundlamuri, Ramesh; Loewe, Thomas; Mundrigi, Ashok; Handt, Sebastian; Singh, Bhuwan

2017-12-14

Cytotoxic drugs can be encapsulated in liposomes vesicles, which act as drug delivery vehicles and reduce the risk of exposure of drug to healthy cells(1). The sterility of such liposome solutions is typically ensured using 0.2μm rated sterilizing grade membranes, but due to the high viscosity and low surface tension of these formulations, they can cause pre-mature blocking and increased risk of bacterial penetration through a 0.2μm sterilizing grade membrane(2). The low surface tension of liposome solutions affects the contact angle with membrane and reduces bubble point leading to bacterial penetration through the membrane. This poses a great challenge to select an appropriate sterilizing grade membrane for a given process and for filter manufacturers to develop a sterilizing grade membrane that specifically addresses these needs. In this study, the influence of different variables that could affect the total throughput and bacterial retention performance of different membranes types on processing of liposome solutions have been evaluated. Based on the results, we conclude that the membrane properties e.g., surface porosity, surface tension, pore size, symmetry/asymmetry, hydrophilicity and liposome properties e.g., composition, lipid size and concentration affect bacterial retention and total throughput capacity. Process parameters such as temperature, pressure and flow should also be optimized to improve process efficiency. Copyright © 2017, Parenteral Drug Association.

Membrane processes for the reuse of car washing wastewater

OpenAIRE

Deniz Uçar

2018-01-01

This study investigates alternative treatments of car wash effluents. The car wash wastewater was treated by settling, filtration, and membrane filtration processes. During settling, total solid concentration decreased rapidly within the first 2 hours and then remained constant. Chemical oxygen demand (COD) and conductivity were decreased by 10% and 4%, respectively. After settling, wastewater was filtered throughout a 100 μm filter. It was found that filtration had a negligible effect on COD...

Si Nanopores Development for External Control of Transport of Biomolecules

International Nuclear Information System (INIS)

Ileri, N.; Tringe, J.; Letant, S.; Palozoglu, A.; Stroeve, P.; Faller, R.

2008-01-01

efficiency of fabricated filters vs. state-of-the-art commercial polycarbonate track-etched (PCTE) membranes. Finally, she has performed preliminary molecular calculations to investigate the operating principles of such systems and she has obtained results which she will present at the international 'Nanostructured materials, membrane modeling and simulation' workshop in Greece

Study on some characteristics of the polycarbonate Durolon used as a solid state nuclear track detector

International Nuclear Information System (INIS)

Sciani, V.; Pugliesi, R.; Moraes, M.A.P.V. de; Menezes, M.O. de; Miranda, A.

1994-01-01

Some characteristics of the polycarbonate Durolon as a solid state nuclear track detector were investigated. These were determined by means of irradiations performed at the IEA-R1 Nuclear Research Reactor of the IPEN-CNEN/SP. The results were compared with those obtained for Makrofol-E at the same conditions. Although Durolon is grooved, it presents a track registration efficiency and a light transmission of about 30% and 2,4 greater than the former, respectively. (author). 7 refs, 4 figs, 2 tabs

Nano sand filter with functionalized nanoparticles embedded in anodic aluminum oxide templates

OpenAIRE

Phuong, NguyenThi; Andisetiawan, Anugrah; Van Lam, Do; Kim, Jeong Hwan; Choi, Doo-Sun; Whang, Kyung-Hyun; Nham, Jeasun; Lee, Yun Jung; Yoo, Yeong-Eun; Yoon, Jae Sung

2016-01-01

Since the ancient Egyptians had used sand as filter media for water purification, its principle has been inherited through generations and it is still being used now in industries. The sand filter consists of sand literally, and the voids within the sand bed are the pores for filtration. Here we present a filtration principle using nanoparticles, so that the voids between the nanoparticles can be considered as effective pores in nanoscale dimension. Anodic aluminum oxide (AAO) membrane has be...

On crystallization of bisphenol-A polycarbonate thin films upon annealing

Energy Technology Data Exchange (ETDEWEB)

Yang, Chunhong; Li, Qichao; Mao, Wenfeng; Wang, Peng; He, Chunqing, E-mail: hecq@whu.edu.cn

2015-10-16

Crystallization of polycarbonate (PC) films as a function of annealing time has been investigated by various methods. A distinct diffraction peak at 17.56°, a sharp decrease of film thickness, an increase of refractive index and branch-type structures on the surface are found merely for the film after crystallization. Interestingly, positron annihilation parameters demonstrate fractional free-volumes in PC films vary significantly not only before crystallization but also at the early stage of annealing, which are not found by other methods. The results show that free-volumes in PC film must be increased remarkably before crystallization, which enables the occurrence of molecule rearrangement. - Highlights: • Fractional free-volume in PC film decreased of early stage of annealing. • Crystallization of PC film on Si substrate occurred after annealed for ∼48 hours. • Fractional free-volume in PC film increased remarkably before crystallization. • Positron diffusion length and S parameter revealed the variation of free volumes.

On crystallization of bisphenol-A polycarbonate thin films upon annealing

International Nuclear Information System (INIS)

Yang, Chunhong; Li, Qichao; Mao, Wenfeng; Wang, Peng; He, Chunqing

2015-01-01

Crystallization of polycarbonate (PC) films as a function of annealing time has been investigated by various methods. A distinct diffraction peak at 17.56°, a sharp decrease of film thickness, an increase of refractive index and branch-type structures on the surface are found merely for the film after crystallization. Interestingly, positron annihilation parameters demonstrate fractional free-volumes in PC films vary significantly not only before crystallization but also at the early stage of annealing, which are not found by other methods. The results show that free-volumes in PC film must be increased remarkably before crystallization, which enables the occurrence of molecule rearrangement. - Highlights: • Fractional free-volume in PC film decreased of early stage of annealing. • Crystallization of PC film on Si substrate occurred after annealed for ∼48 hours. • Fractional free-volume in PC film increased remarkably before crystallization. • Positron diffusion length and S parameter revealed the variation of free volumes

Ozonation and/or Coagulation - Ceramic Membrane Hybrid for Filtration of Impaired-Quality Source Waters

KAUST Repository

Ha, Changwon

2013-09-01

When microfiltration (MF) and ultrafiltration (UF) membranes are applied for drinking water treatment/wastewater reuse, membrane fouling is an evitable problem, causing the loss of productivity over time. Polymeric membranes have been often reported to experience rapid and/or problematical fouling, restraining sustainable operation. Ceramic membranes can be effectively employed to treat impaired-quality source waters due to their inherent robustness in terms of physical and chemical stability. This research aimed to identify the effects of coagulation and/or ozonation on ceramic membrane filtration for seawater and wastewater (WW) effluent. Two different types of MF and UF ceramic membranes obtained by sintering (i.e., TAMI made of TiO2+ZrO2) and anodic oxidation process (i.e., AAO made of Al2O3) were employed for bench-scale tests. Precoagulation was shown to play an important role in both enhancing membrane filterability and natural organic matter (NOM) removal efficacy for treating a highorganic surface water. The most critical factors were found to be pH and coagulant dosage with the highest efficiency resulting under low pH and high coagulant dose. Due to the ozone-resistance nature of the ceramic membranes, preozonation allowed the ceramic membranes to be operated at higher flux, especially leading to significant flux improvement when treating seawater in the presence of calcium and magnesium. 4 Dissolved ozone in contact with the TAMI ceramic membrane surface accelerated the formation of hydroxyl (˙OH) radicals in WW effluent treatment. Flux restoration of both ceramic membranes, fouled with seawater and WW effluent, was efficiently achieved by high backwash (BW) pressure and ozone in chemically enhanced backwashing (CEB). Ceramic membranes exhibited a pH-dependent permeate flux while filtering WW effluent, showing reduced fouling with increased pH. On the other hand, for filtering seawater, differences in permeate flux between the two membranes was

Testing of Synthetic Biological Membranes for Forward Osmosis Applications

Science.gov (United States)

Parodi, Jurek; Mangado, Jaione Romero; Stefanson, Ofir; Flynn, Michael; Mancinelli, Rocco; Kawashima, Brian; Trieu, Serena; Brozell, Adrian; Rosenberg, Kevan

2016-01-01

Commercially available forward osmosis membranes have been extensively tested for human space flight wastewater treatment. Despite the improvements achieved in the last decades, there is still a challenge to produce reliable membranes with anti-fouling properties, chemical resistance, and high flux and selectivity. Synthetic biological membranes that mimic the ones present in nature, which underwent millions of years of evolution, represent a potential solution for further development and progress in membrane technology. Biomimetic forward osmosis membranes based on a polymeric support filter and coated with surfactant multilayers have been engineered to investigate how different manufacturing processes impact the performance and structure of the membrane. However, initial results of the first generation prototype membranes tests reveal a high scatter in the data, due to the current testing apparatus set up. The testing apparatus has been upgraded to improve data collection, reduce errors, and to allow higher control of the testing process.

Treatment of Stormwater using Fibre Filter Media

International Nuclear Information System (INIS)

Johir, M. A. H.; Lee, J. J.; Vigneswaran, S.; Kandasamy, J.; Shaw, K.

2009-01-01

In this study, a high-rate fibre filter was used as a pre-treatment to stormwater in conjunction with in-line flocculation. The effect of operating the fibre filter with different packing densities (105, 115 and 125 kg/m 3 ) and filtration velocities (20, 40, 60 m/h) with and without in-line flocculation was investigated. In-line flocculation was provided using 5, 10 and 15 mg/L of ferric chloride (FeCl 3 .6H 2 O). The filter performance was studied in terms of pressure drop (ΔP), solids removal efficiency, heavy metals (total) removal efficiency and total organic carbon (TOC) removal efficiency. It is found that the use of in-line flocculation at a dose of 15 mg/L improved the performance of fibre filter as measured by turbidity removal (95%), total suspended solids reduction (98%), colour removal efficiency (99%), TOC removal (reduced by 30-40 %) and total coliform removal (93%). The modified fouling index reduced from 750-950 to 12 s/L 2 proving that fibre filter can be an excellent pre-treatment to membrane filtration that may be consider as post-treatment. The removal efficiency of heavy metal was variable as their concentration in raw water was small. Even though the concentration of some of these metals such as iron, aluminium, copper and zinc were reduced, others like nickel, chromium and cadmium showed lower removal rates.

Aliphatic polycarbonate-based polyurethane elastomers and nanocomposites. I. The influence of hard-segment content and macrodiol-constitution on bottom-up self-assembly

Czech Academy of Sciences Publication Activity Database

Špírková, Milena; Poreba, Rafal; Pavličevič, Jelena; Kobera, Libor; Baldrian, Josef; Pekárek, Michal

2012-01-01

Roč. 126, č. 3 (2012), s. 1016-1030 ISSN 0021-8995 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane elastomer * polycarbonate diol * nanocomposite Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.395, year: 2012

Helium ion distributions in a 4 kJ plasma focus device by 1 mm-thick large-size polycarbonate detectors

Energy Technology Data Exchange (ETDEWEB)

Sohrabi, M., E-mail: dr_msohrabi@yahoo.com; Habibi, M.; Ramezani, V.

2014-11-14

Helium ion beam profile, angular and iso-ion beam distributions in 4 kJ Amirkabir plasma focus (APF) device were effectively observed by the unaided eyes and studied in single 1 mm-thick large-diameter (20 cm) polycarbonate track detectors (PCTD). The PCTDs were processed by 50 Hz–HV electrochemical etching using a large-size ECE chamber. The results show that helium ions produced in the APF device have a ring-shaped angular distribution peaked at an angle of ∼±60° with respect to the top of the anode. Some information on the helium ion energy and distributions is also provided. The method is highly effective for ion beam studies. - Highlights: • Helium iso-ion beam profile and angular distributions were studied in the 4 kJ APF device. • Large-area 1 mm-thick polycarbonate detectors were processed by 50 Hz-HV ECE. • Helium ion beam profile and distributions were observed by unaided eyes in a single detector. • Helium ion profile has ring-shaped distributions with energies lower at the ring location. • Helium iso-ion track density, diameter and energy distributions are estimated.

Defective zoospore encystment and suppressed cyst germination of Phytophthora palmivora caused by transient leaching treatments

NARCIS (Netherlands)

Dijksterhuis, J; Deacon, J W

2003-01-01

The behaviour of encysting zoospores of Phytophthora palmivora during leaching conditions was studied. Zoospores encysted and germinated successfully on polycarbonate membranes after mechanical agitation. Transient (10 min) leaching treatments with nutrient-free buffer underneath the membranes

Carbon nanotubes with silver nanoparticle decoration and conductive polymer coating for improving the electrical conductivity of polycarbonate composites

KAUST Repository

Patole, Archana S.

2015-01-01

We proposed a strategy to enhance the conductivity of polycarbonate by using three-phase hybrid metallic/non-metallic fillers. Ethylene diamine (EDA) functionalized multiwalled carbon nanotubes (MWCNT-EDA) are first decorated with silver nanoparticles. These Ag/ MWCNT-EDA fillers are then coated with a conductive layer of ethylene glycol treated PEDOT: PSS (poly [3,4-ethylenedioxythiophene]: poly [styrenesulfonate]) (EP). In such an approach, the MWCNT backbone is covered by a highly conductive coating made of Ag nanoparticles surrounded by EP. To understand how Ag and EP form a highly conductive coating, the effect of different wt% of Ag nanoparticles on EP was studied. Ag nanoparticles around the size of 128 ± 28 nmeffectively lowered the volume resistivity of bulk EP, resulting in a highly conducting Ag/EP blend. We found that in the final Ag/MWCNT-EDA/EP assembly, the EP coating enhances the electrical conductivity in two ways: (1) it is an efficient dispersing agent that helps in achieving a uniform dispersion of the Ag/MWCNT-EDA and (2) it acts as a conductive bridge between particles (Ag and MWCNT-EDA), reducing the particle to particle resistivity. When inserted into polycarbonate, this three-phase blend successfully reduced the volume resistivity of the polymer by two orders of magnitude compared with previous approaches.

Calibration of the polycarbonate dosimeter for the microdosimetry of 239Pu alpha particles in bone

International Nuclear Information System (INIS)

Stillwagon, G.B.; Morgan, K.Z.

1977-01-01

There has been some criticisms of the maximum permissible organ burden (MPOB) in bone for 239 Pu in recent years. These criticisms allude to the relative dearth of experimental data available concerning the actual dose delivered to the endosteal face of osseous tissue by the 239 Pu alpha particle. A dosimeter recently developed has been recommended for application to this microdosimetry problem. The tissue equivalence of polycarbonate dosimeters would allow dose equivalent to be read directly from the foil rather than determining activity from emulsions, in which the alpha particle range is different than in tissue, then relating this activity measurement to absorbed dose by some calculations. Although this dosimeter has been calibrated to read dose equivalent for fast neutron dosimetry, the need exists to determine the factor to multiply by the number of 239 Pu alpha-induced tracks to obtain dose equivalent. This problem is being approached in the following manner. A device called the vacuum-sealed alpha-calibrator has been designed and constructed which will allow the handling of a standard 239 Pu solution obtained for this purpose. The calibrator will first be connected to surface barrier detectors which feed data into a multi-channel analyzer. The counts obtained under the alpha peaks at various heights above the source and the accumulated time are input into a computer program recently written to convert this data into dose rate in rems/unit time. Next the measurements are duplicated, this time using the polycarbonate dosimeter. The results will produce a factor relating the number of alpha-induced tracks to dose

Use of cross-flow membrane filtration in a recirculating hydroponic system to suppress root disease in pepper caused by Pythium myriotylum.

Science.gov (United States)

Schuerger, Andrew C; Hammer, William

2009-05-01

Zoosporic pathogens in the genera Pythium and Phytophthora cause extensive root disease epiphytotics in recirculating hydroponic vegetable-production greenhouses. Zoospore cysts of Pythium myriotylum Drechsler were used to evaluate the effectiveness of cross-flow membrane filters to control pythiaceous pathogens in recirculating hydroponic systems. Four membrane filter brands (Honeycomb, Polypure, Polymate, and Absolife) were tested alone or in combination to determine which filters would effectively remove infective propagules of P. myriotylum from solutions and reduce disease incidence and severity. Zoospore cysts of P. myriotylum generally measured 8 to 10 microm, and it was hypothesized that filters with pore-sizespepper plants from root infection. Single-filter assays with Honeycomb and Polypure brands removed 85 to 95% of zoospore cysts when pore sizes were rated at 1, 5, 10, 20, or 30 microm. Single-filter assays of Polymate and Absolife brands were more effective, exhibiting apparently 100% removal of zoospore cysts from nutrient solutions on filters rated at 1 to 10 microm. However, plant bioassays with Honeycomb and Polymate single filters failed to give long-term protection of pepper plants. Double-filter assays with 1- and 0.5-microm Polymate filters significantly increased the protection of pepper plants grown in nutrient film technique systems but, eventually, root disease and plant wilt could be observed. Insect transmissions by shore flies were not factors in disease development. Scanning electron microscopy images of zoospore cysts entrapped on Polymate filters revealed zoospore cysts that were either fully encysted, partially encysted, or of unusually small size (3 microm in diameter). It was concluded that either the atypically small or pliable pleomorphic zoospore cysts were able to penetrate filter membranes that theoretically should have captured them.

Polycarbonate crowns for primary teeth revisited: restorative options, technique and case reports.

Science.gov (United States)

Venkataraghavan, Karthik; Chan, John; Karthik, Sandhya

2014-01-01

Esthetics by definition is the science of beauty - that particular detail of an animate or inanimate object that makes it appealing to the eye. In the modern, civilized, and cosmetically conscious world, well-contoured and well-aligned white teeth set the standard for beauty. Such teeth are not only considered attractive but are also indicative of nutritional health, self esteem, hygienic pride, and economic status. Numerous treatment approaches have been proposed to address the esthetics and retention of restorations in primary teeth. Even though researchers have claimed that certain restorations are better than the others, particularly owing to the issues mentioned above, the search for the ideal esthetic restoration for the primary teeth continues. This paper revisits and attempts to reintroduce the full coverage restoration, namely, polycarbonate crown, for use in primary anterior teeth.

Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

International Nuclear Information System (INIS)

Ugucioni, J.C.; Ghilardi Netto, T.; Mulato, M.

2010-01-01

Mercuric iodide (HgI 2 ) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI 2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 o C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI 2 crystalline device.

Membrane Characteristics for Removing Particulates in PFC Wastes

International Nuclear Information System (INIS)

Kim, Gye Nam; Lee, Sung Yeol; Won, Hui Jun; Jung, Chong Hun; Oh, Won Zin; Park, Jin Ho

2005-01-01

Pc (Per fluorocarbon) decontamination process is one of best methods to remove hot particulate adhered at inside surface of hot cell and surface of equipment in hot cell. It was necessary to develop a particulate filtration equipment to reuse Pc solution used on Pc decontamination due to its high cost and to minimize the volume of second wastewater. Contamination characteristics of hot particulate were investigated and then a filtration process was presented to remove hot particulate in Pc solution generated through Pc decontamination process. The removal efficiency of Pvdf (Poly vinylidene fluoride), Pp (Polypropylene), Ceramic (Al 2 O 3 ) filter showed more than 95%. The removal efficiency of Pvdf filter was a little lower than those of other kiters at same pressure (3 psi). A ceramic filter showed a higher removal efficiency with other filters, while a little lower flux rate than other filters. Due to inorganic composition, a ceramic filter was highly stable against radio nuclides in comparison with Pvdf and Pp membrane, which generate H 2 gas in α-radioactivity atmosphere. Therefore, the adoption of ceramic filter is estimated to be suitable for the real nitration process.

Polyvinylidene Fluoride Micropore Membranes as Solid-Phase Extraction Disk for Preconcentration of Nanoparticulate Silver in Environmental Waters.

Science.gov (United States)

Zhou, Xiao-Xia; Lai, Yu-Jian; Liu, Rui; Li, Sha-Sha; Xu, Jing-Wen; Liu, Jing-Fu

2017-12-05

Efficient separation and preconcentration of trace nanoparticulate silver (NAg) from large-volume environmental waters is a prerequisite for reliable analysis and therefore understanding the environmental processes of silver nanoparticles (AgNPs). Herein, we report the novel use of polyvinylidene fluoride (PVDF) filter membrane for disk-based solid phase extraction (SPE) of NAg in 1 L of water samples with the disk-based SPE system, which consists of a syringe pump and a syringe filter holder to embed the filter membrane. While the PVDF membrane can selectively adsorb NAg in the presence of Ag + , aqueous solution of 2% (m/v) FL-70 is found to efficiently elute NAg. Analysis of NAg is performed following optimization of filter membrane and elution conditions with an enrichment factor of 1000. Additionally, transmission electron microscopy (TEM), UV-vis spectroscopy, and size-exclusion chromatography coupled with ICP-MS (SEC-ICP-MS) analysis showed that the extraction gives rise to no change in NAg size or shape, making this method attractive for practical applications. Furthermore, feasibility of the protocol is verified by applying it to extract NAg in four real waters with recoveries of 62.2-80.2% at 0.056-0.58 μg/L spiked levels. This work will facilitate robust studies of trace NAg transformation and their hazard assessments in the environment.

Dissolution Model Development: Formulation Effects and Filter Complications

DEFF Research Database (Denmark)

Berthelsen, Ragna; Holm, Rene; Jacobsen, Jette

2016-01-01

This study describes various complications related to sample preparation (filtration) during development of a dissolution method intended to discriminate among different fenofibrate immediate-release formulations. Several dissolution apparatus and sample preparation techniques were tested. The fl....... With the tested drug–formulation combination, the best in vivo–in vitro correlation was found after filtration of the dissolution samples through 0.45-μm hydrophobic PTFE membrane filters....

Collection of size fractionated particulate matter sample for neutron activation analysis in Japan

International Nuclear Information System (INIS)

Otoshi, Tsunehiko; Nakamatsu, Hiroaki; Oura, Yasuji; Ebihara, Mitsuru

2004-01-01

According to the decision of the 2001 Workshop on Utilization of Research Reactor (Neutron Activation Analysis (NAA) Section), size fractionated particulate matter collection for NAA was started from 2002 at two sites in Japan. The two monitoring sites, ''Tokyo'' and ''Sakata'', were classified into ''urban'' and ''rural''. In each site, two size fractions, namely PM 2-10 '' and PM 2 '' particles (aerodynamic particle size between 2 to 10 micrometer and less than 2 micrometer, respectively) were collected every month on polycarbonate membrane filters. Average concentrations of PM 10 (sum of PM 2-10 and PM 2 samples) during the common sampling period of August to November 2002 in each site were 0.031mg/m 3 in Tokyo, and 0.022mg/m 3 in Sakata. (author)

Electrochemical aptasensor for detecting Der p2 allergen using polycarbonate-based double-generation gold nanoparticle chip

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Ming-Che Shen

2017-04-01

Full Text Available In this study, a novel aptamer-based impedimetric biosensor for detecting the group 2 allergen of Dermatophagoides pteronyssinus (Der p2 was developed. First, an anodic aluminum oxide (AAO membrane was prepared. A modified AAO barrier-layer surface with an array of nanohemispheres of 400 nm in diameter was used as a template for the nanoelectroforming of a nickel mold. After electroforming, the AAO template was etched and a nickel nanomold with a concave nanostructure array was produced. The formed nanostructured nickel nanomold was then used in the replica molding of a nanostructured polycarbonate (PC substrate via hot embossing. Finally, a gold thin film was sputtered onto the PC substrate to form a double-generation gold nanoparticle electrode (array of nanohemispheres with smaller nanoparticles orderly distributed on each nanohemisphere. After immobilizing specifically designed aptamers on the fabricated electrode, electrochemical impedance spectroscopy was used to determine the concentration of Der p2. The sensitivity of the proposed scheme for the detection of the dust mite antigen Der p2 was 2.088 Ω / (ng/mL × cm2 with a dynamic detection range of 27.5–400 ng/mL and detection limit of 16.47 ng/mL.The aptamer-based impedimetric biosensor proposed in this study possesses many advantages such as high sensitivity, low cost, and high consistency over currently used sensors. The proposed sensor was found to be useful for the rapid detection of rare molecules present in an analyte. Keywords: Aptamers, Der p2 dust mite allergen detection, Nanostructured biosensors, Electrochemical impedance spectroscopy

Influence of nitrogen on the tribological properties of a-C:H layers on the polycarbonate substrates

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Rafal M. Nowak

2008-12-01

Full Text Available Polycarbonate (PC possesses many commercial applications. However, PC is still limited to non-abrasive and chemical-free environments due to its low hardness, low scratching resistance and high susceptibility to chemical attacks. To overcome this limitation, PC can be coated by hydrogenated amorphous carbon layers. The a-C:H layers have very attractive properties such as high hardness, infrared transparency, chemical inertness, low friction coefficients, and biocompatibility. Addition of nitrogen in the structure allows lowering internal stress and improve tribological properties of a-C:H layers. In this work, a-C:N:H layers were deposited from mixture CH4/N2 gases by RF PECVD method. Effects of the nitrogen incorporation on structure and tribological properties of deposited layers were investigated. The structure of layers were characterized by Fourier Transform Infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS. The friction coefficient, wear resistance of a-C:H:N layers were estimated by tribometer in ball-on-disc configuration. The IR spectra of the obtained layers have demonstrated a presence of nitrogen bonded both to carbon and to hydrogen. A formation of the following bonds has been confirmed: -C≡N, -NH2, -C−NH2, >C=NH. They are all typical for a-C:N:H layers. The tribological tests have shown that the layers reduce the friction coefficient of the polycarbonate (up to 50 % and considerably improve wear resistance.

The use of the polycarbonate in solar dissipative; El uso del policarbonato en disposistivos solares

Energy Technology Data Exchange (ETDEWEB)

Fasulo, A.; Barral, J.; Ducculi, E.; Varela, P.; Nieto, M.

2008-07-01

This work describes the good qualities and limitations the alveolar polycarbonate has. The experience on using this material is the starting point of the work: the successful experiments and the problems encounter in some other trials. The problems motivated the analysis the material nature to look for practical conclusions. The results showed that this materials is not apt to work in permanent contact with water. Mechanical tests were performed in order to investigate if the deterioration process is detectable after short exposition periods- These tests showed that the materials maintains its properties after 500 hours of exposition. Photographs and plots are presented. (Author)

Using polycarbonate dyed with dansyl chloride for dosimetry in radiation processing

International Nuclear Information System (INIS)

Feizi, Shazad; Ziaie, Farhood; Ghandi, Mehdi

2015-01-01

Preparation and characteristics evaluation of the polycarbonate films 20 μm in thickness containing Dansyl chloride as a routine dosimeter in radiation processing facilities were studied. The sensitivity of these films and the linearity of dose-response curves were investigated under 60 Co γ-rays in a dose range of 0-100 kGy, and the obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the maximum absorbance appeared at 370 nm in all the investigated dose range. The dyed films were found to be stable enough in mediums with high degrees of humidity and temperature, to be reliably used in radio-applications. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were also discussed. The films which were made displayed stable characteristics when stored in dark, within 1% at 25 C, 3 months after irradiation.

Effect of Immobilized Antithrombin III on the Thromboresistance of Polycarbonate Urethane.

Science.gov (United States)

Lukas, Karin; Stadtherr, Karin; Gessner, Andre; Wehner, Daniel; Schmid, Thomas; Wendel, Hans Peter; Schmid, Christof; Lehle, Karla

2017-03-24

The surface of foils and vascular grafts made from a thermoplastic polycarbonate urethanes (PCU) (Chronoflex AR) were chemically modified using gas plasma treatment, binding of hydrogels-(1) polyethylene glycol bisdiamine and carboxymethyl dextran (PEG-DEX) and (2) polyethyleneimine (PEI)-and immobilization of human antithrombin III (AT). Their biological impact was tested in vitro under static and dynamic conditions. Static test methods showed a significantly reduced adhesion of endothelial cells, platelets, and bacteria, compared to untreated PCU. Modified PCU grafts were circulated in a Chandler-Loop model for 90 min at 37 °C with human blood. Before and after circulation, parameters of the hemostatic system (coagulation, platelets, complement, and leukocyte activation) were analyzed. PEI-AT significantly inhibited the activation of both coagulation and platelets and prevented the activation of leukocytes and complement. In conclusion, both modifications significantly reduce coagulation activation, but only PEI-AT creates anti-bacterial and anti-thrombogenic functionality.

Electrically tunable solid-state silicon nanopore ion filter

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Gracheva Maria

2006-01-01

Full Text Available AbstractWe show that a nanopore in a silicon membrane connected to a voltage source can be used as an electrically tunable ion filter. By applying a voltage between the heavily doped semiconductor and the electrolyte, it is possible to invert the ion population inside the nanopore and vary the conductance for both cations and anions in order to achieve selective conduction of ions even in the presence of significant surface charges in the membrane. Our model based on the solution of the Poisson equation and linear transport theory indicates that in narrow nanopores substantial gain can be achieved by controlling electrically the width of the charge double layer.

Evaluation of the MF/UF Performance for the Reuse of Sand Filter Backwash Water from Drinking Water Treatment Plants

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Neda Shirzadi

2015-05-01

Full Text Available The aim of this study was to investigate the application of micro-filtration and ultra-filtration membrane systems in order to improve the physical and microbial quality and the reuse of backwash water from the sand filter units in water treatment plants. The backwash water from filters makes up for 3 to 5 percent of the total water treated, which is disposed in most WTPs. However, the treatment and reuse of the backwash water is more admissible from technical and economic viewpoints, especially in view of the present water scarcity. For the purposes of this study, use was made of membrane modules of micro- and ultra-filters on a pilot scale. The micro-filter employed consisted of a polypropylene membrane module with a porosity of 1 micron in size and a fiberglass module with a porosity of 5 microns. The ultra-filter was made of PVC hollow fiber with a molecular weight of 100,000 Dalton. In order to feed the two pilots, backwash water from a sand filter was collected from one of the WTPs in Tehran. After samples were taken from the backwash water, the physical and microbial removal efficiency was periodically evaluated based on the standard method and the micro-filtration, ultra-filtration, and combined MF/UF processes were compared with respect to their performance. The results indicate that the combined MF/UF process is able to decrease turbidity, MPN, COD, TSS, and Fe with efficiency values of 99.9, 100, 61.5, 99.9 and 98.8 percent, respectively. Overall, the findings confirmed the technical capabilities of this method for the recovery and reuse of the effluent produced in the backwashing mechanism of sand filters in WTPs.

Crossflow Ultra-filter Module Draining and Flush Testing for the Hanford Tank Waste Treatment and Immobilization Plant - Lessons Learned in De-clogging Crossflow Filters

International Nuclear Information System (INIS)

Townson, P.S.; Brackenbury, P.J.

2009-01-01

This paper describes test work conducted in order to study crossflow ultra-filter module draining and flushing for the Hanford Tank Waste Treatment and Immobilization Plant. The objective of the testing was to demonstrate that the current design, with a flush tank at elevation 29.9 m (98'-00'') has enough pressure head to drain (to a minimum elevation ∼1.5 m [∼5'-00'']) and clean out the ultra-filter tube side. Without demonstrating this, a potential failure of the flush system could cause immovable solids to plug the tubular membranes of the filters causing serious adverse impacts to plant availability and/or throughput, and could permit deleterious flammable gas accumulations. In conjunction with the water flush, the plant also utilizes air purging to prevent build up of flammable gases. Two filter configurations were investigated, one being the baseline horizontal layout and one being an alternative vertical layout. The slurry used in the tests was a non radioactive simulant (kaolin-bentonite clay), and it mimicked the rheological properties of the real waste slurry. The filter modules were full scale items, being 2.44 m (8') in length and containing 241 by 1.3 cm (1/2'') id sintered stainless steel filter tubes. (authors)

Reuse of filter backwash water with a submerged microfiltration membrane system; Wiederverwendung von Filterspuelwaessern durch Mikrofiltration mit getauchten Membranen

Energy Technology Data Exchange (ETDEWEB)

Koetzle, T.; Merkl, G.; Wilderer, P. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl und Lab. fuer Wasserguete- und Abfallwirtschaft; Backhaus, J. [Erlanger Stadtwerke AG, Erlangen (Germany); Hagen, K. [VA TECH WABAG GmbH Kulmbach, Kulmbach (Germany)

2000-12-01

During the treatment of groundwater by filtration for drinking water purposes, approximately 3% of the treated water volume has to be used as filter backwash water. Until now this backwash water charged with the accumulated filtrate is then redirected into sewers or receiving waters, either directly or after a sedimentation step. With sufficient separation of the filtered substances from backwash water this could again be used for drinking water purposes. This conserves natural groundwater resources and significantly reduces the volume of wastewater discharged. Especially in the face of the increasing shortage of useable groundwater resources in many countries, this will become increasingly important in the future. In our project, supported by 'EU-Life', the Technical University of Munich will examine on a large-scale plant according to the WABAG-SMS-Process, how far cross-flow microfiltration is capable of purifying the backwash waters for drinking water purposes again. The pilot-plant consists of two treatment parts, one charged with backwash water from the iron-, manganese- and arsenic-elimination, the other charged with backwash water from the deacidification. The membrane modules are submerged in closed storage basins for backwash water. Air is supplied under the modules to generate a defined cross-flow. This article discusses the results after one year of operation of the plant. (orig.) [German] Bei der Aufbereitung von Grundwasser durch Filtration in der Trinkwasseraufbereitung muessen etwa 3% der aufbereiteten Wassermenge zur Rueckspuelung der Filter verwendet werden. Bisher werden die hierbei anfallenden und mit den zuvor abfiltrierten Stoffen belasteten Filterspuelwaesser je nach den oertlichen Gegebenheiten unmittelbar oder nach einer Sedimentationsstufe in Vorfluter oder die oeffentliche Sammelkanalisation abgeschlagen. Durch eine hinreichende Trennung der abfiltrierten Stoffe vom Filterspuelwasser koennte dieses wieder der

Etude de quelques conditions influençant la filtration des vins sur membrane

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M. Salgues

1982-12-01

The filterability test proposed by Gaillard helps to estimate the volume of wine that can be filtered by a winery, to control and optimise the assembly line preparation of wines. Different applications are studied. The water flowrate test allows a better control of clopping and of membrane regeneration. Regeneration technics by soaking in detergent solutions are studied and proposed.

Impact of granular filtration on ultrafiltration membrane performance as pre-treatment to seawater desalination in presence of algal blooms

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Nour-Eddine Sabiri

2018-04-01

Full Text Available To mitigate fouling of the ultrafiltration (UF membrane and improve permeate quality, we coupled granular filters (GF with UF membrane as a pre-treatment for reconstituted seawater in the presence of algal bloom. Mono and bilayer granular filtrations were led at a mean velocity of 10 m h−1 over a 7-hour period. Both GF gave the same algal cell retention rate (∼63% after 7 hours of filtration. Turbidity reduction rate was 50% for the monolayer filter and 75% for the bilayer filter. Resulting organic matter removal rate was 10% for the monolayer filter and 35% for the bilayer filter. Dissolved organic carbon removal was low (20% with the bilayer filter and non-existent with the monolayer filter. GF-coupled UF reduced humic acids in the permeate (20% compared with UF alone. Peak pressure of 3 bars was reached at the end of 30 minutes of UF in both direct UF or UF after monolayer GF. The filtrate from the bilayer GF enables UF over a longer period (7 hours.

Electrochemically etched nanoporous silicon membrane for separation of biological molecules in mixture

Science.gov (United States)

Burham, Norhafizah; Azlan Hamzah, Azrul; Yunas, Jumril; Yeop Majlis, Burhanuddin

2017-07-01

This paper presents a technique for separating biological molecules in mixture using nanoporous silicon membrane. Nanopores were formed using electrochemical etching process (ECE) by etching a prefabricated silicon membrane in hydrofluoric acid (HF) and ethanol, and then directly bonding it with PDMS to form a complete filtration system for separating biological molecules. Tygon S3™ tubings were used as fluid interconnection between PDMS molds and silicon membrane during testing. Electrochemical etching parameters were manipulated to control pore structure and size. In this work, nanopores with sizes of less than 50 nm, embedded on top of columnar structures have been fabricated using high current densities and variable HF concentrations. Zinc oxide was diluted with deionized (DI) water and mixed with biological molecules and non-biological particles, namely protein standard, serum albumin and sodium chloride. Zinc oxide particles were trapped on the nanoporous silicon surface, while biological molecules of sizes up to 12 nm penetrated the nanoporous silicon membrane. The filtered particles were inspected using a Zetasizer Nano SP for particle size measurement and count. The Zetasizer Nano SP results revealed that more than 95% of the biological molecules in the mixture were filtered out by the nanoporous silicon membrane. The nanoporous silicon membrane fabricated in this work is integratable into bio-MEMS and Lab-on-Chip components to separate two or more types of biomolecules at once. The membrane is especially useful for the development of artificial kidney.

Measurement of filtration efficiency of Nuclepore filters challenged with polystyrene latex nanoparticles: experiments and modeling

International Nuclear Information System (INIS)

Ling, Tsz Yan; Wang Jing; Pui, David Y. H.

2011-01-01

Membrane filtration has been demonstrated to be effective for the removal of liquid-borne nanoparticles (NPs). Such technique can be applied to purify and disinfect drinking water as well as remove NPs in highly pure chemicals used in the industries. This study aims to study the filtration process of a model membrane filter, the Nuclepore filter. Experiments were carried out using standard filtration tools and the nanoparticle tracking analysis (NTA) technique was used to measure particle (50–500 nm) concentration upstream and downstream of the filter to determine the filtration efficiency. The NTA technique has been calibrated using 150-nm polystyrene latex particles to determine its accuracy of particle concentration measurement. Measurements were found reliable within a certain concentration limit (about 10 8 –10 10 particles/cm 3 ), which is dependent on the camera settings during the measurement. Experimental results are comparable with previously published data obtained using the aerosolization method, validating the capability of the NTA technique. The capillary tube model modified from that developed for aerosol filtration was found to be useful to represent the experimental results, when a sticking coefficient of 0.15 is incorporated. This suggests that only 15% of the particle collisions with the filter results in successful attachment. The small sticking coefficient found can be explained by the unfavorable surface interactions between the particles and the filter medium.

Anti-biofilm activity of Fe heavy ion irradiated polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Joshi, R.P. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Hareesh, K., E-mail: appi.2907@gmail.com [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Bankar, A. [Department of Microbiology, Waghire College, Pune 412301 (India); Sanjeev, Ganesh [Microtron Centre, Department of Studies in Physics, Mangalore University, Mangalore 574166 (India); Asokan, K.; Kanjilal, D. [Inter University Accelerator Centre, Arun Asaf Ali Marg, New Delhi 110067 (India); Dahiwale, S.S.; Bhoraskar, V.N. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-10-01

Highlights: • PC films were irradiated by 60 and 120 MeV Fe ions. • Irradiated PC films showed changes in its physical and chemical properties. • Irradiated PC also showed more anti-biofilm activity compared to pristine PC. - Abstract: Polycarbonate (PC) polymers were investigated before and after high energy heavy ion irradiation for anti-bacterial properties. These PC films were irradiated by Fe heavy ions with two energies, viz, 60 and 120 MeV, at different fluences in the range from 1 × 10{sup 11} ions/cm{sup 2} to 1 × 10{sup 13} ions/cm{sup 2}. UV-Visible spectroscopic results showed optical band gap decreased with increase in ion fluences due to chain scission mainly at carbonyl group of PC which is also corroborated by Fourier transform infrared spectroscopic results. X-ray diffractogram results showed decrease in crystallinity of PC after irradiation which leads to decrease in molecular weight. This is confirmed by rheological studies and also by differential scanning calorimetric results. The irradiated PC samples showed modification in their surfaces prevents biofilm formation of human pathogen, Salmonella typhi.

Treatment of Stormwater using Fibre Filter Media

Energy Technology Data Exchange (ETDEWEB)

Johir, M. A. H.; Lee, J. J.; Vigneswaran, S., E-mail: s.vigneswaran@uts.edu.au; Kandasamy, J. [University of Technology, Faculty of Engineering and IT (Australia); Shaw, K. [Veolia Water Solutions and Technologies Australia (Australia)

2009-12-15

In this study, a high-rate fibre filter was used as a pre-treatment to stormwater in conjunction with in-line flocculation. The effect of operating the fibre filter with different packing densities (105, 115 and 125 kg/m{sup 3}) and filtration velocities (20, 40, 60 m/h) with and without in-line flocculation was investigated. In-line flocculation was provided using 5, 10 and 15 mg/L of ferric chloride (FeCl{sub 3}.6H{sub 2}O). The filter performance was studied in terms of pressure drop ({Delta}P), solids removal efficiency, heavy metals (total) removal efficiency and total organic carbon (TOC) removal efficiency. It is found that the use of in-line flocculation at a dose of 15 mg/L improved the performance of fibre filter as measured by turbidity removal (95%), total suspended solids reduction (98%), colour removal efficiency (99%), TOC removal (reduced by 30-40 %) and total coliform removal (93%). The modified fouling index reduced from 750-950 to 12 s/L{sup 2} proving that fibre filter can be an excellent pre-treatment to membrane filtration that may be consider as post-treatment. The removal efficiency of heavy metal was variable as their concentration in raw water was small. Even though the concentration of some of these metals such as iron, aluminium, copper and zinc were reduced, others like nickel, chromium and cadmium showed lower removal rates.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Polymer blends of polycarbonate (PC) and polysulphone (PSF) having thickness, 27 m, are prepared by solution cast method. The transport properties of pores in a blend membrane are examined. The pores were produced in this membrane by a track etching technique. For this purpose, a thin polymer membrane was ...

Membrane separation using nano-pores; Nano poa wo riyoshita makubunri

Energy Technology Data Exchange (ETDEWEB)

Manabe, S. [Fukuoka Women`s Univ., Fukuoka (Japan)

1995-08-01

The membrane constituted by nano-pore only (NF membrane) is sold on the market recently as the membranes used for the matter separations in addition to the reverse osmosis membrane for changing seawater into fresh water, dialysis membrane used for artificial kidney, ultrafiltration membrane used for the separation and condensation of protein and the micro-filter used for removing microbe. It is possible for the membrane constituted by nano-pore to remove the virus with the size being from 20 to 300 nm. In this paper, the pore structure of NF membrane is explained, and then its application as the membrane for removing virus is described. Especially, it is possible for NF membrane to remove the virus with smallest size (parvovirus, etc.), prion albumen (bovine serum pathogen, etc.) and the special gene such as cancer, and it is further applied to the condensation and refining of virus and genes. The broader application of nano-pore to the control of the transportation of micro-particles in the future is expected. 3 refs., 2 figs.

Polycarbonate crowns for primary teeth revisited: Restorative options, technique and case reports

Directory of Open Access Journals (Sweden)

Karthik Venkataraghavan

2014-01-01

Full Text Available Esthetics by definition is the science of beauty - that particular detail of an animate or inanimate object that makes it appealing to the eye. In the modern, civilized, and cosmetically conscious world, well-contoured and well-aligned white teeth set the standard for beauty. Such teeth are not only considered attractive but are also indicative of nutritional health, self esteem, hygienic pride, and economic status. Numerous treatment approaches have been proposed to address the esthetics and retention of restorations in primary teeth. Even though researchers have claimed that certain restorations are better than the others, particularly owing to the issues mentioned above, the search for the ideal esthetic restoration for the primary teeth continues. This paper revisits and attempts to reintroduce the full coverage restoration, namely, polycarbonate crown, for use in primary anterior teeth.

INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS

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María Casamitjanaa Causa

2015-06-01

Full Text Available Membrane bioreactors (MBR technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor, anoxic recirculation (from the aerobic to the anoxic reactor and anaerobic recirculation (from the anoxic to the anaerobic reactor]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP, which seems to depend on external and anoxic sludge recirculation.

Synthesis, Characterization and Epoxidation of cis-Enriched New Polycarbonates Catalyzed by Efficient Organotin Compound

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A. H. Massoudi

2011-01-01

Full Text Available Presence of active functional groups on polymer chain is a suitable aspect of polymer structure which allows performing next favourite reactions on polymer molecule. In this research a novel aromatic derivative of cis-but-2-endiol was synthesized as monomer. The synthesized monomer was polymerized using diphenyl carbonate and 1,4-butandiol as second and third monomer along with organotin catalyst. Polymerization reaction performed by using melt-phase transesterification process to produce a new terpolymer of polycarbonate. During the reaction the double bonds are preserved on polymer chain and epoxidized by m-chloroperbenzoic acid (MCBPA in good yield to demonstrate the reactivity and possibility of performing further reactions on double bonds of polymer.

Design Concepts of Polycarbonate-Based Intervertebral Lumbar Cages: Finite Element Analysis and Compression Testing

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J. Obedt Figueroa-Cavazos

2016-01-01

Full Text Available This work explores the viability of 3D printed intervertebral lumbar cages based on biocompatible polycarbonate (PC-ISO® material. Several design concepts are proposed for the generation of patient-specific intervertebral lumbar cages. The 3D printed material achieved compressive yield strength of 55 MPa under a specific combination of manufacturing parameters. The literature recommends a reference load of 4,000 N for design of intervertebral lumbar cages. Under compression testing conditions, the proposed design concepts withstand between 7,500 and 10,000 N of load before showing yielding. Although some stress concentration regions were found during analysis, the overall viability of the proposed design concepts was validated.

Research on Permeability of Poly(ethylene) Terephthalate Track Membranes Modified in Plasma

CERN Document Server

Dmitriev, S N; Sleptsov, V V; Elinson, V M; Potrjasaj, V V

2001-01-01

The properties of poly(ethylene) terephthalate track membranes subjected to the plasma RF-discharge treatment in air have been investigated. The effect of the treatment conditions in plasma on the structure and the properties of the membranes formed in the gas-discharge etching has been studied. It has been figured out that the influence of the air plasma on the membranes under study leads to a formation of asymmetric membranes with a higher flow rate, the structure and chemical composition of their superficial layer are changed. It is shown that the presence of the modified layer on the surface of the membranes causes changing their hydrodynamic characteristics - water permeability of the membranes treated in plasma in a greater degree depends upon {pH} of the filtered solution.

Investigation of different types of filters for atmospheric trace elements analysis by three analytical techniques

International Nuclear Information System (INIS)

Ali, A.E.; Bacso, J.

1996-01-01

Different atmospheric aerosol samples were collected on three types of filters. Disks of both loaded and clean areas of each kind of filter were investigated by XRF, PIXE and Scanning Electron Microscope (SEM) methods. The blank concentration values of the elements Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br and Pb in the three types of filters are discussed. It is found that for trace elemental analysis, the Nuclepore membrane filters are the most suitable for sampling. These have much lower blank element concentration values than the glass fibres and ash free filters. It was found also that the PIXE method is a more reliable analytical technique for atmospheric aerosol particles than the other methods. (author). 20 refs., 3 figs., 3 tabs

Using polycarbonate dyed with dansyl chloride for dosimetry in radiation processing

Energy Technology Data Exchange (ETDEWEB)

Feizi, Shazad; Ziaie, Farhood [Nuclear Science and Technology Research Institute, Radiation Application Research School, Tehran (Iran, Islamic Republic of); Ghandi, Mehdi [Univ. Tehran (Iran, Islamic Republic of). School of Chemistry

2015-07-01

Preparation and characteristics evaluation of the polycarbonate films 20 μm in thickness containing Dansyl chloride as a routine dosimeter in radiation processing facilities were studied. The sensitivity of these films and the linearity of dose-response curves were investigated under {sup 60}Co γ-rays in a dose range of 0-100 kGy, and the obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the maximum absorbance appeared at 370 nm in all the investigated dose range. The dyed films were found to be stable enough in mediums with high degrees of humidity and temperature, to be reliably used in radio-applications. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were also discussed. The films which were made displayed stable characteristics when stored in dark, within 1% at 25 C, 3 months after irradiation.

Use of UV-vis-NIR spectroscopy to monitor label-free interaction between molecular recognition elements and erythropoietin on a gold-coated polycarbonate platform.

Science.gov (United States)

Citartan, Marimuthu; Gopinath, Subash C B; Tominaga, Junji; Chen, Yeng; Tang, Thean-Hock

2014-08-01

Label-free-based detection is pivotal for real-time monitoring of biomolecular interactions and to eliminate the need for labeling with tags that can occupy important binding sites of biomolecules. One simplest form of label-free-based detection is ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, which measure changes in reflectivity as a means to monitor immobilization and interaction of biomolecules with their corresponding partners. In biosensor development, the platform used for the biomolecular interaction should be suitable for different molecular recognition elements. In this study, gold (Au)-coated polycarbonate was used as a platform and as a proof-of-concept, erythropoietin (EPO), a doping substance widely abused by the athletes was used as the target. The interaction of EPO with its corresponding molecular recognition elements (anti-EPO monoclonal antibody and anti-EPO DNA aptamer) is monitored by UV-vis-NIR spectroscopy. Prior to this, to show that UV-vis-NIR spectroscopy is a suitable method for measuring biomolecular interaction, the interaction between biotin and streptavidin was demonstrated via this strategy and reflectivity of this interaction decreased by 25%. Subsequent to this, interaction of the EPO with anti-EPO monoclonal antibody and anti-EPO DNA aptamer resulted in the decrease of reflectivity by 5% and 10%, respectively. The results indicated that Au-coated polycarbonate could be an ideal biosensor platform for monitoring biomolecular interactions using UV-vis-NIR spectroscopy. A smaller version of the Au-coated polycarbonate substrates can be derived from the recent set-up, to be applied towards detecting EPO abuse among atheletes. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of enhanced membrane bioreactor (eMBR) to treat dye wastewater.

Science.gov (United States)

Rondon, Hector; El-Cheikh, William; Boluarte, Ida Alicia Rodriguez; Chang, Chia-Yuan; Bagshaw, Steve; Farago, Leanne; Jegatheesan, Veeriah; Shu, Li

2015-05-01

An enhanced membrane bioreactor (eMBR) consisting of two anoxic bioreactors (ARs) followed by an aerated membrane bioreactor (AMBR), UV-unit and a granular activated carbon (GAC) filter was employed to treat 50-100 mg/L of remazol blue BR dye. The COD of the feed was 2334 mg/L and COD:TN:TP in the feed was 119:1.87:1. A feed flow rate of 5 L/d was maintained when the dye concentration was 50 mg/L; 10 L/d of return activated sludge was recirculated to each AR from the AMBR. Once the biological system is acclimatised, 95% of dye, 99% of COD, 97% of nitrogen and 73% of phosphorus were removed at a retention time of 74.4 h. When the effluent from the AMBR was drawn at a flux rate of 6.5 L/m(2)h, the trans-membrane pressure reached 40 kPa in every 10 days. AMBR effluent was passed through the UV-unit and GAC filter to remove the dye completely. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study on the etching conditions of polycarbonate detectors for particle analysis of safeguards environmental samples

International Nuclear Information System (INIS)

Iguchi, K.; Esaka, K.T.; Lee, C.G.; Inagawa, J.; Esaka, F.; Onodera, T.; Fukuyama, H.; Suzuki, D.; Sakurai, S.; Watanabe, K.; Usuda, S.

2005-01-01

The fission track technique was applied to the particle analysis for safeguards environmental samples to obtain information about the isotope ratio of nuclear materials in individual particles. To detect the particles containing nuclear material with high detection efficiency and less particle loss, the influence of uranium enrichments on etching conditions of a fission track detector made of polycarbonate was investigated. It was shown that the increase in uranium enrichment shortened the suitable etching time both for particle detection and for less particle loss. From the results obtained, it was suggested that the screening of the uranium particles according to the enrichment is possible by controlling the etching time of the detector

The transfer of rare earth elements through liquid extraction membranes

International Nuclear Information System (INIS)

Kapranchik, V.P.; Proyaev, V.V.; Kopyrin, A.A.

1988-01-01

The transfer of rare earth elements through liquid extraction membranes, presenting Dacron nuclear filters, impregnated by extractants of different types (tributylphosphine oxide; di-2-ethylhexylphosphoric acid, HDEHP; trioctylamine, TOA) is investigated. It is ascertained that in systems with extractant-carriers TOA and HDEHP inversion of dependences of flow values and distribution coefficients on the element atomic number is observed. Mathematical model of transfer, permitting to establish relation between extractional and transport characteristics of the membrane, is suggested

Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

NARCIS (Netherlands)

Willige, van R.W.G.; Linssen, J.P.H.; Legger, A.; Voragen, A.G.J.

2003-01-01

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic

Polycarbonate-based benzo-δ-sultam films for high-dose dosimetry in radiation processing

International Nuclear Information System (INIS)

Feizi, Shazad; Nuclear Science and Technology Research Institute, Tehran; Ziaie, Farhood; Ghandi, Mehdi

2015-01-01

In this work characteristics of the polycarbonate films with 20 μm in thickness containing different weight percentage of Benzo-δ-sultam were studied for use as a high dose dosimetry system in radiation processing facilities. The sensitivity of the dosimeters and the linearity of dose-response curves were investigated under 60 Co γ-rays in a dose range of 0-100 kGy, and obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the absorbance at 348 nm depends linearly on the dose in the investigated dose range. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight are also discussed. The results show that the dosimeters characteristics are stable within 1% at 25 C, 3 months after the irradiation.

Short Term Evaluation of an Anatomically Shaped Polycarbonate Urethane Total Meniscus Replacement in a Goat Model.

Directory of Open Access Journals (Sweden)

A C T Vrancken

Full Text Available Since the treatment options for symptomatic total meniscectomy patients are still limited, an anatomically shaped, polycarbonate urethane (PCU, total meniscus replacement was developed. This study evaluates the in vivo performance of the implant in a goat model, with a specific focus on the implant location in the joint, geometrical integrity of the implant and the effect of the implant on synovial membrane and articular cartilage histopathological condition.The right medial meniscus of seven Saanen goats was replaced by the implant. Sham surgery (transection of the MCL, arthrotomy and MCL suturing was performed in six animals. The contralateral knee joints of both groups served as control groups. After three months follow-up the following aspects of implant performance were evaluated: implant position, implant deformation and the histopathological condition of the synovium and cartilage.Implant geometry was well maintained during the three month implantation period. No signs of PCU wear were found and the implant did not induce an inflammatory response in the knee joint. In all animals, implant fixation was compromised due to suture breakage, wear or elongation, likely causing the increase in extrusion observed in the implant group. Both the femoral cartilage and tibial cartilage in direct contact with the implant showed increased damage compared to the sham and sham-control groups.This study demonstrates that the novel, anatomically shaped PCU total meniscal replacement is biocompatible and resistant to three months of physiological loading. Failure of the fixation sutures may have increased implant mobility, which probably induced implant extrusion and potentially stimulated cartilage degeneration. Evidently, redesigning the fixation method is necessary. Future animal studies should evaluate the improved fixation method and compare implant performance to current treatment standards, such as allografts.

High-throughput single-molecule force spectroscopy for membrane proteins

Science.gov (United States)

Bosshart, Patrick D.; Casagrande, Fabio; Frederix, Patrick L. T. M.; Ratera, Merce; Bippes, Christian A.; Müller, Daniel J.; Palacin, Manuel; Engel, Andreas; Fotiadis, Dimitrios

2008-09-01

Atomic force microscopy-based single-molecule force spectroscopy (SMFS) is a powerful tool for studying the mechanical properties, intermolecular and intramolecular interactions, unfolding pathways, and energy landscapes of membrane proteins. One limiting factor for the large-scale applicability of SMFS on membrane proteins is its low efficiency in data acquisition. We have developed a semi-automated high-throughput SMFS (HT-SMFS) procedure for efficient data acquisition. In addition, we present a coarse filter to efficiently extract protein unfolding events from large data sets. The HT-SMFS procedure and the coarse filter were validated using the proton pump bacteriorhodopsin (BR) from Halobacterium salinarum and the L-arginine/agmatine antiporter AdiC from the bacterium Escherichia coli. To screen for molecular interactions between AdiC and its substrates, we recorded data sets in the absence and in the presence of L-arginine, D-arginine, and agmatine. Altogether ~400 000 force-distance curves were recorded. Application of coarse filtering to this wealth of data yielded six data sets with ~200 (AdiC) and ~400 (BR) force-distance spectra in each. Importantly, the raw data for most of these data sets were acquired in one to two days, opening new perspectives for HT-SMFS applications.

High-throughput single-molecule force spectroscopy for membrane proteins

International Nuclear Information System (INIS)

Bosshart, Patrick D; Casagrande, Fabio; Frederix, Patrick L T M; Engel, Andreas; Fotiadis, Dimitrios; Ratera, Merce; Palacin, Manuel; Bippes, Christian A; Mueller, Daniel J

2008-01-01

Atomic force microscopy-based single-molecule force spectroscopy (SMFS) is a powerful tool for studying the mechanical properties, intermolecular and intramolecular interactions, unfolding pathways, and energy landscapes of membrane proteins. One limiting factor for the large-scale applicability of SMFS on membrane proteins is its low efficiency in data acquisition. We have developed a semi-automated high-throughput SMFS (HT-SMFS) procedure for efficient data acquisition. In addition, we present a coarse filter to efficiently extract protein unfolding events from large data sets. The HT-SMFS procedure and the coarse filter were validated using the proton pump bacteriorhodopsin (BR) from Halobacterium salinarum and the L-arginine/agmatine antiporter AdiC from the bacterium Escherichia coli. To screen for molecular interactions between AdiC and its substrates, we recorded data sets in the absence and in the presence of L-arginine, D-arginine, and agmatine. Altogether ∼400 000 force-distance curves were recorded. Application of coarse filtering to this wealth of data yielded six data sets with ∼200 (AdiC) and ∼400 (BR) force-distance spectra in each. Importantly, the raw data for most of these data sets were acquired in one to two days, opening new perspectives for HT-SMFS applications

High-throughput single-molecule force spectroscopy for membrane proteins

Energy Technology Data Exchange (ETDEWEB)

Bosshart, Patrick D; Casagrande, Fabio; Frederix, Patrick L T M; Engel, Andreas; Fotiadis, Dimitrios [M E Mueller Institute for Structural Biology, Biozentrum of the University of Basel, CH-4056 Basel (Switzerland); Ratera, Merce; Palacin, Manuel [Institute for Research in Biomedicine, Barcelona Science Park, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona and Centro de Investigacion Biomedica en Red de Enfermedades Raras, E-08028 Barcelona (Spain); Bippes, Christian A; Mueller, Daniel J [BioTechnology Center, Technical University, Tatzberg 47, D-01307 Dresden (Germany)], E-mail: andreas.engel@unibas.ch, E-mail: dimitrios.fotiadis@mci.unibe.ch

2008-09-24

Atomic force microscopy-based single-molecule force spectroscopy (SMFS) is a powerful tool for studying the mechanical properties, intermolecular and intramolecular interactions, unfolding pathways, and energy landscapes of membrane proteins. One limiting factor for the large-scale applicability of SMFS on membrane proteins is its low efficiency in data acquisition. We have developed a semi-automated high-throughput SMFS (HT-SMFS) procedure for efficient data acquisition. In addition, we present a coarse filter to efficiently extract protein unfolding events from large data sets. The HT-SMFS procedure and the coarse filter were validated using the proton pump bacteriorhodopsin (BR) from Halobacterium salinarum and the L-arginine/agmatine antiporter AdiC from the bacterium Escherichia coli. To screen for molecular interactions between AdiC and its substrates, we recorded data sets in the absence and in the presence of L-arginine, D-arginine, and agmatine. Altogether {approx}400 000 force-distance curves were recorded. Application of coarse filtering to this wealth of data yielded six data sets with {approx}200 (AdiC) and {approx}400 (BR) force-distance spectra in each. Importantly, the raw data for most of these data sets were acquired in one to two days, opening new perspectives for HT-SMFS applications.

Novel Cleanup Agents Designed Exclusively for Oil Field Membrane Filtration Systems Low Cost Field Demonstrations of Cleanup Agents in Controlled Experimental Environments

Energy Technology Data Exchange (ETDEWEB)

David Burnett; Harold Vance

2007-08-31

The goal of our project is to develop innovative processes and novel cleaning agents for water treatment facilities designed to remove fouling materials and restore micro-filter and reverse osmosis (RO) membrane performance. This project is part of Texas A&M University's comprehensive study of the treatment and reuse of oilfield brine for beneficial purposes. Before waste water can be used for any beneficial purpose, it must be processed to remove contaminants, including oily wastes such as residual petroleum hydrocarbons. An effective way of removing petroleum from brines is the use of membrane filters to separate oily waste from the brine. Texas A&M and its partners have developed highly efficient membrane treatment and RO desalination for waste water including oil field produced water. We have also developed novel and new cleaning agents for membrane filters utilizing environmentally friendly materials so that the water from the treatment process will meet U.S. EPA drinking water standards. Prototype micellar cleaning agents perform better and use less clean water than alternate systems. While not yet optimized, the new system restores essentially complete membrane flux and separation efficiency after cleaning. Significantly the amount of desalinated water that is required to clean the membranes is reduced by more than 75%.

Research on permeability of poly(ethylene) terephthalate track membranes modified in plasma

International Nuclear Information System (INIS)

Dmitriev, S.N.; Kravets, L.I.; Sleptsov, V.V.; Elinson, V.M.; Potryasaj, V.V.

2001-01-01

The properties of poly(ethylene) terephthalate track membranes subjected to the plasma RF-discharge treatment in air have been investigated. The effect of the treatment conditions in plasma on the structure and the properties of the membranes formed in the gas-discharge etching has been studied. It has been figured out that the influence of the air plasma on the membranes under study leads to a formation of asymmetric membranes with a higher flow rate, the structure and chemical composition of their superficial layer are changed. It is shown that the presence of the modified layer on the surface of the membranes causes changing their hydrodynamic characteristics - water permeability of the membranes treated in plasma in a greater degree depends upon pH of the filtered solution. (author)

Refractive-index-based screening of membrane-protein-mediated transfer across biological membranes.

Science.gov (United States)

Brändén, Magnus; Tabaei, Seyed R; Fischer, Gerhard; Neutze, Richard; Höök, Fredrik

2010-07-07

Numerous membrane-transport proteins are major drug targets, and therefore a key ingredient in pharmaceutical development is the availability of reliable, efficient tools for membrane transport characterization and inhibition. Here, we present the use of evanescent-wave sensing for screening of membrane-protein-mediated transport across lipid bilayer membranes. This method is based on a direct recording of the temporal variations in the refractive index that occur upon a transfer-dependent change in the solute concentration inside liposomes associated to a surface plasmon resonance (SPR) active sensor surface. The applicability of the method is demonstrated by a functional study of the aquaglyceroporin PfAQP from the malaria parasite Plasmodium falciparum. Assays of the temperature dependence of facilitated diffusion of sugar alcohols on a single set of PfAQP-reconstituted liposomes reveal that the activation energies for facilitated diffusion of xylitol and sorbitol are the same as that previously measured for glycerol transport in the aquaglyceroporin of Escherichia coli (5 kcal/mole). These findings indicate that the aquaglyceroporin selectivity filter does not discriminate sugar alcohols based on their length, and that the extra energy cost of dehydration of larger sugar alcohols, upon entering the pore, is compensated for by additional hydrogen-bond interactions within the aquaglyceroporin pore. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Research on water permeability of poly(ethylene) terephthalate track membranes modified with plasma

International Nuclear Information System (INIS)

Kravets, L.I.; Dmitriev, S.N.; Sleptsov, V.V.; Elinson, V.M.; Potryasay, V.V.

2001-01-01

The properties of poly(ethylene) terephthalate track membranes subjected to effect of plasma of the RF-discharge in air have been investigated. The influence conditions of a plasma treatment on the surface properties and hydrodynamic characteristics of the membranes has been studied. It has been found that the effect of the air plasma on the researched membranes results in a formation of asymmetric track membranes with a higher flow rate, the structure and chemical composition of their superficial layer are changed. It was shown that the availability of the modified layer on the membrane surface caused changing in their hydrodynamic characteristics - the water permeability of the membranes, processed in plasma, in a greater degree depends upon pH of a filtered solution. (author)

Aluminium - Cobalt-Pillared Clay for Dye Filtration Membrane

Science.gov (United States)

Darmawan, A.; Widiarsih

2018-04-01

The manufacture of membrane support from cobalt aluminium pillared clay has been conducted. This research was conducted by mixing a clay suspension with pillared solution prepared from the mixture of Co(NO3)2.6H2O and AlCl3.6H2O. The molar ratio between Al and Co was 75:25 and the ratio of [OH-]/[metal] was 2. The clay suspension was stirred for 24 hours at room temperature, filtered and dried. The dried clay was then calcined at 200°C, 300°C and 400°C with a ramp rate of 2°C/min. Aluminium-cobalt-pillared clay was then characterized by XRD and GSA and moulded become a membrane support for subsequent tests on dye filtration. The XRD analysis showed that basal spacing (d 001) value of aluminium cobalt was 19.49 Å, which was higher than the natural clay of 15.08Å however, the basal spacing decreased with increasing calcination temperature. The result of the GSA analysis showed that the pore diameter of the aluminium cobalt pillared clay membrane was almost the same as that of natural clay that were 34.5Å and 34.2Å, respectively. Nevertheless, the pillared clay has a more uniform pore size distribution. The results of methylene blue filtration measurements demonstrated that the membrane filter support could well which shown by a clear filtrate at all concentrations tested. The value of rejection and flux decreased with the increasing concentration of methylene blue. The values of dye rejection and water flux reached 99.89% and 5. 80 x 10-6 kg min-1, respectively but they decreased with increasing concentration of methylene blue. The results of this study indicates that the aluminium-pillared clay cobalt could be used as membrane materials especially for ultrafiltration.

Permeability optimization and performance evaluation of hot aerosol filters made using foam incorporated alumina suspension.

Science.gov (United States)

Innocentini, Murilo D M; Rodrigues, Vanessa P; Romano, Roberto C O; Pileggi, Rafael G; Silva, Gracinda M C; Coury, José R

2009-02-15

Porous ceramic samples were prepared from aqueous foam incorporated alumina suspension for application as hot aerosol filtering membrane. The procedure for establishment of membrane features required to maintain a desired flow condition was theoretically described and experimental work was designed to prepare ceramic membranes to meet the predicted criteria. Two best membranes, thus prepared, were selected for permeability tests up to 700 degrees C and their total and fractional collection efficiencies were experimentally evaluated. Reasonably good performance was achieved at room temperature, while at 700 degrees C, increased permeability was obtained with significant reduction in collection efficiency, which was explained by a combination of thermal expansion of the structure and changes in the gas properties.

ZnO/Al{sub 2}O{sub 3} coatings for the photoprotection of polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Moustaghfir, A. [Laboratoire des Materiaux Inorganiques, UMR CNRS 6002, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France); Tomasella, E. [Laboratoire des Materiaux Inorganiques, UMR CNRS 6002, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France); Jacquet, M. [Laboratoire des Materiaux Inorganiques, UMR CNRS 6002, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France)]. E-mail: jacquet@chimie.univ-bpclermont.fr; Rivaton, A. [Laboratoire de Photochimie Moleculaire et Macromoleculaire, UMR CNRS 6505, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France); Mailhot, B. [Laboratoire de Photochimie Moleculaire et Macromoleculaire, UMR CNRS 6505, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France); Gardette, J.L. [Laboratoire de Photochimie Moleculaire et Macromoleculaire, UMR CNRS 6505, Universite Blaise Pascal (Clermont-Fd), 63177 Aubiere Cedex (France); Beche, E. [PROMES, Odeillo, 66125 Font-Romeu Cedex (France)

2006-10-25

ZnO and ZnO/Al{sub 2}O{sub 3} thin films were deposited by r.f. magnetron sputtering on polycarbonate (PC) films in order to protect this polymer against photodegradation. The composition, structure and optical properties of the ceramic coatings were characterised. CO{sub 2}-plasma treatments were applied to PC in order to improve the coating adhesion. The PC surface energy was characterised by wettability measurements and the chemical bonds were analysed by XPS. It was found that ZnO coatings improve the stability of PC to UV radiations and that an intermediate alumina coating inhibits the photocatalytic oxidation of PC at the PC/ZnO interface. Additionally an external alumina coating brings a high hardness to the coating.

Membrane bioreactors' potential for ethanol and biogas production: a review.

Science.gov (United States)

Ylitervo, Päivi; Akinbomia, Julius; Taherzadeha, Mohammad J

2013-01-01

Companies developing and producing membranes for different separation purposes, as well as the market for these, have markedly increased in numbers over the last decade. Membrane and separation technology might well contribute to making fuel ethanol and biogas production from lignocellulosic materials more economically viable and productive. Combining biological processes with membrane separation techniques in a membrane bioreactor (MBR) increases cell concentrations extensively in the bioreactor. Such a combination furthermore reduces product inhibition during the biological process, increases product concentration and productivity, and simplifies the separation of product and/or cells. Various MBRs have been studied over the years, where the membrane is either submerged inside the liquid to be filtered, or placed in an external loop outside the bioreactor. All configurations have advantages and drawbacks, as reviewed in this paper. The current review presents an account of the membrane separation technologies, and the research performed on MBRs, focusing on ethanol and biogas production. The advantages and potentials of the technology are elucidated.

Effects of membrane-filtered soy hull pectin and pre-emulsified fiber/oil on chemical and technological properties of low fat and low salt meat emulsions.

Science.gov (United States)

Kim, Hyun-Wook; Lee, Yong Jae; Kim, Yuan H Brad

2016-06-01

The objectives of this study were to determine efficacy of a membrane filtration in soy hull pectin purification and evaluate combined effects of soy hull pectin and pre-emulsified fiber/oil (PE) on chemical composition and technological properties of low fat and low salt meat emulsions. Soy hull pectin was purified through two different methods (alcohol-washed (ASP) and membrane-filtered (MSP)). Insoluble soy hull residues after pectin extraction were incorporated with sunflower oil and water for the PE preparation. Meat emulsion was formulated with 58 % pork, 20 % ice, 20 % pork backfat, and 2 % NaCl as control. A total of six low fat and low salt meat emulsions (1 % NaCl and 10 % backfat) was manufactured with 1 % pectin (with/without ASP or MSP) and 10 % PE (with/without). The pectin content of ASP and MSP was 0.84 and 0.64 g L-galacturonic acid/g dry sample, respectively. The inclusion of soy hull pectin caused similar results on chemical composition, color, cooking loss, and texture of the meat emulsions, regardless of the purification method. In addition, positive impacts of the combined treatments with soy hull pectin and PE compared to single treatments on cooking loss and texture of the meat emulsions were observed. Results suggest that membrane filtration could be an effective alternative method to purify pectin, instead of alcohol-washing, and both soluble pectin and insoluble fiber from soy hulls could be used as a functional non-meat ingredient to manufacture various low fat and low salt meat products.

The role of polycarbonate monomer bisphenol-A in insulin resistance.

Science.gov (United States)

Pjanic, Milos

2017-01-01

Bisphenol A (BPA) is a synthetic unit of polycarbonate polymers and epoxy resins, the types of plastics that could be found in essentially every human population and incorporated into almost every aspect of the modern human society. BPA polymers appear in a wide range of products, from liquid storages (plastic bottles, can and glass linings, water pipes and tanks) and food storages (plastics wraps and containers), to medical and dental devices. BPA polymers could be hydrolyzed spontaneously or in a photo- or temperature-catalyzed process, providing widespread environmental distribution and chronic exposure to the BPA monomer in contemporary human populations. Bisphenol A is also a xenoestrogen, an endocrine-disrupting chemical (EDC) that interferes with the endocrine system mimicking the effects of an estrogen and could potentially keep our endocrine system in a constant perturbation that parallels endocrine disruption arising during pregnancy, such as insulin resistance (IR). Gestational insulin resistance represents a natural biological phenomenon of higher insulin resistance in peripheral tissues of the pregnant females, when nutrients are increasingly being directed to the embryo instead of being stored in peripheral tissues. Gestational diabetes mellitus may appear in healthy non-diabetic females, due to gestational insulin resistance that leads to increased blood sugar levels and hyperinsulinemia (increased insulin production from the pancreatic beta cells). The hypothesis states that unnoticed and constant exposure to this environmental chemical might potentially lead to the formation of chronic low-level endocrine disruptive state that resembles gestational insulin resistance, which might contribute to the development of diabetes. The increasing body of evidence supports the major premises of this hypothesis, as exemplified by the numerous publications examining the association of BPA and insulin resistance, both epidemiological and mechanistic. However, to

Effectiveness of Membrane Filtration to Improve Drinking Water: A Quasi-Experimental Study from Rural Southern India.

Science.gov (United States)

Francis, Mark Rohit; Sarkar, Rajiv; Roy, Sheela; Jaffar, Shabbar; Mohan, Venkata Raghava; Kang, Gagandeep; Balraj, Vinohar

2016-11-02

Since point-of-use methods of water filtration have shown limited acceptance in Vellore, southern India, this study evaluated the effectiveness of decentralized membrane filtration 1) with safe storage, 2) without safe storage, versus 3) no intervention, consisting of central chlorination as per government guidelines, in improving the microbiological quality of drinking water and preventing childhood diarrhea. Periodic testing of water sources, pre-/postfiltration samples, and household water, and a biweekly follow up of children less than 2 years of age was done for 1 year. The membrane filters achieved a log reduction of 0.86 (0.69-1.06), 1.14 (0.99-1.30), and 0.79 (0.67-0.94) for total coliforms, fecal coliforms, and Escherichia coli, respectively, in field conditions. A 24% (incidence rate ratio, IRR [95% confidence interval, CI] = 0.76 [0.51-1.13]; P = 0.178) reduction in diarrheal incidence in the intervention village with safe storage and a 14% (IRR [95% CI] = 1.14 [0.75-1.77]; P = 0.530) increase in incidence for the intervention village without safe storage versus no intervention village was observed, although not statistically significant. Microbiologically, the membrane filters decreased fecal contamination; however, provision of decentralized membrane-filtered water with or without safe storage was not protective against childhood diarrhea. © The American Society of Tropical Medicine and Hygiene.

Monte Carlo simulations of radioactive waste encapsulated by bisphenol-A polycarbonate and effect of bismuth-III oxide filler material

International Nuclear Information System (INIS)

Özdemir, Tonguç

2017-01-01

Radioactive waste generated from the nuclear industry and non-power applications should carefully be treated, conditioned and disposed according to the regulations set by the competent authority(ies). Bisphenol-a polycarbonate (BPA-PC), a very widely used polymer, might be considered as a potential candidate material for low level radioactive waste encapsulation. In this work, the dose rate distribution in the radioactive waste drum (containing radioactive waste and the BPA-PC polymer matrix) was determined using Monte Carlo simulations. Moreover, the change of mechanical properties of BPA-PC was estimated and their variation within the waste drum was determined for the periods of 15, 30 and 300 years after disposal to the final disposal site. The change of the dose rate within the waste drum with different contents of bismuth-III oxide were also simulated. It was concluded that addition of bismuth-III oxide filler decreases the dose delivered to the polymeric matrix due to photoelectric effect. - Highlights: • Bisphenol-a polycarbonate (BPA-PC) is a widely used polymeric material and have a considerable gamma radiation stability. • BPA-PC could have a potential candidate material for radioactive waste embedding. • Activity of the radioactive waste that could be embedded into the BPA-PC matrix was simulated. • Effect of bismuth-III-oxide filler to the BPA-PC matrix was determined.

Asymmetric designed sintered metal filter elements in the HTF process of LILW vitrification plant

International Nuclear Information System (INIS)

Roehlig, Rainer

2005-01-01

Sintered metal filter elements have been used for years and have been successfully in operation in different application. The technical and economical advantages of only recently developed asymmetric Metallic Membranes elements, which operate as a surface filter, will be shown in comparison with standard sintered metal filter cartridges. The permeability, particle retention and back flushing performance have been improved. In order to achieve this, an asymmetric structure was designed in which an active filtration layer is applied onto a coarse porous metal support material made out of the same alloy. The economical benefits for customers are low maintenance and reduced investment cost as well as defined particle retention as is required by the users

Study on the structure of bridge surface of the micro Fabry-Perot cavity tunable filter

International Nuclear Information System (INIS)

Meng Qinghua; Luo Huan; Bao Shiwei; Zhou Yifan; Chen Sihai

2011-01-01

Micro Fabry-Perot cavity tunable filters are widely applied in the area of Pushbroom Hyperspectral imaging, DWDM optical communication system and self-adaptive optics. With small volume, lower consumption and cost, the Micro Fabry-Perot cavity tunable filter can realize superior response speed, large spectral range, high definition and high reliability. By deposition metal membrane on silicon chip by MEMS technology, the micro Fabry-Perot cavity has been achieved, which is actuated by electrostatic force and can realize the function of an optical filter. In this paper, the micro-bridge structure of the micro Fabry-Perot cavity tunable filter has been studied. Finite element analysis software COMSOL Multiphysics has been adopted to design the structure of the micro-bridge of the micro filter. In order to simulate the working mechanism of the micro Fabry-Perot cavity and study the electrical and mechanical characteristics of the micro tunable filter,the static and dynamic characteriastics are analyzed, such as stress, displacement, transient response, etc. The corresponding parameters of the structure are considered as well by optimizition the filter's sustain structure.

Study of the joining of polycarbonate panels in butt joint configuration through friction stir welding

Science.gov (United States)

Astarita, Antonello; Boccarusso, Luca; Carrino, Luigi; Durante, Massimo; Minutolo, Fabrizio Memola Capece; Squillace, Antonino

2018-05-01

Polycarbonate sheets, 3 mm thick, were successfully friction stir welded in butt joint configuration. Aiming to study the feasibility of the process and the influence of the process parameters joints under different processing conditions, obtained by varying the tool rotational speed and the tool travel speed, were realized. Tensile tests were carried out to characterize the joints. Moreover the forces arising during the process were recorded and carefully studied. The experimental outcomes proved the feasibility of the process when the process parameters are properly set, joints retaining more than 70% of the UTS of the base material were produced. The trend of the forces was described and explained, the influence of the process parameters was also introduced.

First scientific application of the membrane cryostat technology

Energy Technology Data Exchange (ETDEWEB)

Montanari, David; Adamowski, Mark; Baller, Bruce R.; Barger, Robert K.; Chi, Edward C.; Davis, Ronald P.; Johnson, Bryan D.; Kubinski, Bob M.; Najdzion, John J.; Rucinski, Russel A.; Schmitt, Rich L.; Tope, Terry E. [Particle Physics Division, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); Mahoney, Ryan; Norris, Barry L.; Watkins, Daniel J. [Technical Division, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); McCluskey, Elaine G. [LBNE Project, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); Stewart, James [Physics Department, Brookhaven National Laboratory, P.O. Box 5000, Uptown, NY 11973 (United States)

2014-01-29

We report on the design, fabrication, performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with IHI Corporation (IHI). Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon, and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the purity requirements in a membrane cryostat without evacuation and using only a controlled gaseous argon purge; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon during filling, purification, and maintenance mode using mole sieve and copper filters from the Liquid Argon Purity Demonstrator (LAPD) R and D project. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion oxygen equivalent. This paper gives the requirements, design, construction, and performance of the LBNE membrane cryostat prototype, with experience and results important to the development of the LBNE detector.

Si Nanopores Development for External Control of Transport of Biomolecules

Energy Technology Data Exchange (ETDEWEB)

Ileri, N; Tringe, J; Letant, S; Palozoglu, A; Stroeve, P; Faller, R

2008-06-13

efficiency of fabricated filters vs. state-of-the-art commercial polycarbonate track-etched (PCTE) membranes. Finally, she has performed preliminary molecular calculations to investigate the operating principles of such systems and she has obtained results which she will present at the international 'Nanostructured materials, membrane modeling and simulation' workshop in Greece.

Assay of hybrid ribonuclease using a membrane filter-immobilized synthetic hybrid: application to the human leukemic cell

International Nuclear Information System (INIS)

Papaphilis, A.D.; Kamper, E.F.

1985-01-01

A method for assaying hybrid ribonuclease has been devised which utilizes as substrate the synthetic hybrid [ 3 H]polyriboadenylic acid [poly(rA)]:polydeoxythymidylic acid [poly(dT)] immobilized on the solid matrix of nitrocellulose filters. The hybridization on filter of [ 3 H]poly(rA) to poly(dT) has been explored in terms of efficacy of the process and the response of the product to RNase H. A pulse of uv irradiation of poly(dT) while in dry state on the filter increased its firm binding to the filter in a concentration-dependent manner, resulting in a concomitant increase of the yield of hybrid formation. The filter-immobilized hybrid was 95% resistant to RNase A but sensitive to RNase H. When stored in toluene in the cold the hybrid maintained its stability for over 6 months, as judged by its resistance to RNase A. The method offers a number of advantages over assays that use solution hybrids as substrates and was readily applicable in the screening of leukemic patients, in the leukocytes of which it has demonstrated increased RNase H levels

Palladium-103 plaque radiation therapy for ciliary body melanoma through a functioning glaucoma filtering bleb.

Science.gov (United States)

Pathan, Arif H K; Barash, Alexander; Tena, Lawrence B; Finger, Paul T

2018-01-01

To provide a clinical description of the long-term outcome of a 103 Pd plaque-irradiated ciliary body melanoma with extrascleral extension while attempting to preserve a subadjacent glaucoma filtering bleb. A 75-year-old woman with pseudoexfoliative glaucoma for 17 years, 16 years status post argon laser trabeculoplasty, and 15 years status post trabeculectomy in the left eye, was diagnosed with an ipsilateral ciliary body melanoma with visible extrascleral extension. Treatment involved insertion of a 103 Pd radioactive plaque over the functioning trabeculectomy, with removal 7 days later. At plaque insertion, amniotic membrane grafts were used to cover the plaque and protect the filtering site. The tumor was successfully treated without clinical evidence of harm to the filtering bleb, with resultant stable intraocular pressure. However, the patient developed blebitis 1.5 years later. Though it resolved with topical antibiotic therapy, the bleb became less succulent. Two years postoperatively, she developed a spontaneous hyphema that resolved after one injection of transscleral bevacizumab 1.25 mg. Her tumor continually regressed in thickness. Without additional glaucoma surgery, her intraocular pressure remained well-controlled on topical medications for 6 years. Ciliary body melanoma with minimal extrascleral extension beneath a functioning filtering bleb can be treated using radioactive plaque therapy. In this case, we were able to achieve both tumor regression and glaucoma control by covering the plaque with an amniotic membrane graft.

Copper ion implantation of polycarbonate matrices: Morphological and structural properties

Energy Technology Data Exchange (ETDEWEB)

Resta, V., E-mail: vincenzo.resta@le.infn.it; Quarta, G.; Maruccio, L.; Calcagnile, L.

2014-07-15

The implantation of 1 MeV {sup 63}Cu{sup +} ions in polycarbonate (PC) matrices has been carried out in order to evaluate the morphological and structural modifications induced in the polymer as a function of the ion fluence in the range 5 × 10{sup 13} ions cm{sup −2} to 1 × 10{sup 17} ions cm{sup −2}. Atomic Force Microscopy analysis reveals a significant roughness increase of the polymer surface only for fluences higher than 5 × 10{sup 16} ions cm{sup −2} with the presence of hillock structures which surface density increases with increasing the ion fluence. X-ray Diffraction measurements of PC implanted with fluences in the range between 5 × 10{sup 15} at cm{sup −2} and 5 × 10{sup 16} at cm{sup −2} reveal an increase of the disorder inside the PC matrix, as a consequence of the damaging process induced by the ion irradiation. Evidences about the presence of exotic phase structures ascribed to both cubic Cu{sub 2}O and cubic Cu have been found.

Improving electrical conductivity in polycarbonate nanocomposites using highly conductive PEDOT/PSS coated MWCNTs

KAUST Repository

Zhou, Jian

2013-07-10

We describe a strategy to design highly electrically conductive polycarbonate nanocomposites by using multiwalled carbon nanotubes (MWCNTs) coated with a thin layer of poly(3,4-ethylenedioxythiophene)/ poly(styrenesulfonate), a conductive polymer. We found that this coating method improves the electrical properties of the nanocomposites in two ways. First, the coating becomes the main electrical conductive path. Second, the coating promotes the formation of a percolation network at a low filler concentration (0.3 wt %). To tailor the electrical properties of the conductive polymer coating, we used a polar solvent ethylene glycol, and we can tune the final properties of the nanocomposite by controlling the concentrations of the elementary constituents or the intrinsic properties of the conductive polymer coating. This very flexible technique allows for tailoring the properties of the final product. © 2013 American Chemical Society.

Evolution of nanodot morphology on polycarbonate (PC) surfaces by 40 keV Ar"+

International Nuclear Information System (INIS)

Goyal, Meetika; Chawla, Mahak; Gupta, Divya; Shekhawat, Nidhi; Sharma, Annu; Aggarwal, Sanjeev

2016-01-01

In the present paper we have discussed the effect of 40 keV Ar"+ ions irradiation on nanoscale surface morphology of Polycarbonate (PC) substrate. Specimens were sputtered at off normal incidences of 30°, 40° and 50° with the fluence of 1 × 10"1"6 Ar"+cm"−"2. The topographical behaviour of specimens was studied by using Atomic Force Microscopy (AFM) technique. AFM study demonstrates the evolution of nano dot morphology on PC specimens on irradiating with 1 × 10"1"6 Ar"+cm"−"2. Average size of dots varied from 37-95 nm in this specified range of incidence while density of dots varied from 0.17-3.0 × 107 dotscm"−"2. Such variations in morphological features have been supported by estimation of ion range and sputtering yield through SRIM simulations.

Effect of electron beam irradiation on the thermal properties of polycarbonate / polyester blend

International Nuclear Information System (INIS)

Zarie, K.A.

2007-01-01

The effect of electron beam irradiation on the thermal properties of Bayfol (polycarbonate/polyester blend) solid state nuclear track detector (SSNTD) was investigated. Non-isothermal studies were carried out using thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) to obtain the activation energy of thermal decomposition for Bayfol detector. The thermogravimetric analysis (TGA) indicated that the Bayfol samples were decomposed in one main break down stage. Samples of 250 μm thickness sheets were exposed to electron beam irradiations in the dose range 20-600 KGy. The variation of melting temperatures with the electron dose was determined using differential thermal analysis (DTA). The results indicated that the electron irradiation in the dose range 200-600 KGy decreases the melting temperature of the Bayfol samples and this is most suitable for applications requiring the molding of this polymer at lower temperatures

Polycarbonate-based benzo-δ-sultam films for high-dose dosimetry in radiation processing

Energy Technology Data Exchange (ETDEWEB)

Feizi, Shazad [University of Tehran, Tehran (India). School of Chemistry; Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ziaie, Farhood [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ghandi, Mehdi [University of Tehran, Tehran (India). School of Chemistry

2015-05-01

In this work characteristics of the polycarbonate films with 20 μm in thickness containing different weight percentage of Benzo-δ-sultam were studied for use as a high dose dosimetry system in radiation processing facilities. The sensitivity of the dosimeters and the linearity of dose-response curves were investigated under {sup 60}Co γ-rays in a dose range of 0-100 kGy, and obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the absorbance at 348 nm depends linearly on the dose in the investigated dose range. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight are also discussed. The results show that the dosimeters characteristics are stable within 1% at 25 C, 3 months after the irradiation.

Carbon nanostructured films modified by metal nanoparticles supported on filtering membranes for electroanalysis.

Science.gov (United States)

Paramo, Erica; Palmero, Susana; Heras, Aranzazu; Colina, Alvaro

2018-02-01

A novel methodology to prepare sensors based on carbon nanostructures electrodes modified by metal nanoparticles is proposed. As a proof of concept, a novel bismuth nanoparticle/carbon nanofiber (Bi-NPs/CNF) electrode and a carbon nanotube (CNT)/gold nanoparticle (Au-NPs) have been developed. Bi-NPs/CNF films were prepared by 1) filtering a dispersion of CNFs on a polytetrafluorethylene (PTFE) filter, and 2) filtering a dispersion of Bi-NPs chemically synthesized through this CNF/PTFE film. Next the electrode is prepared by sticking the Bi-NPs/CNF/PTFE film on a PET substrate. In this work, Bi-NPs/CNF ratio was optimized using a Cd 2+ solution as a probe sample. The Cd anodic stripping peak intensity, registered by differential pulse anodic stripping voltammetry (DPASV), is selected as target signal. The voltammograms registered for Cd stripping with this Bi-NPs/CNF/PTFE electrode showed well-defined and highly reproducible electrochemical. The optimized Bi-NPs/CNF electrode exhibits a Cd 2+ detection limit of 53.57 ppb. To demonstrate the utility and versatility of this methodology, single walled carbon nanotubes (SWCNTs) and gold nanoparticles (Au-NPs) were selected to prepare a completely different electrode. Thus, the new Au-NPs/SWCNT/PTFE electrode was tested with a multiresponse technique. In this case, UV/Vis absorption spectroelectrochemistry experiments were carried out for studying dopamine, demonstrating the good performance of the Au-NPs/SWCNT electrode developed. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of Zosteric Acid for Mitigating Biofilm Formation of Pseudomonas putida Isolated from a Membrane Bioreactor System

Directory of Open Access Journals (Sweden)

Andrea Polo

2014-05-01

Full Text Available This study provides data to define an efficient biocide-free strategy based on zosteric acid to counteract biofilm formation on the membranes of submerged bioreactor system plants. 16S rRNA gene phylogenetic analysis showed that gammaproteobacteria was the prevalent taxa on fouled membranes of an Italian wastewater plant. Pseudomonas was the prevalent genus among the cultivable membrane-fouler bacteria and Pseudomonas putida was selected as the target microorganism to test the efficacy of the antifoulant. Zosteric acid was not a source of carbon and energy for P. putida cells and, at 200 mg/L, it caused a reduction of bacterial coverage by 80%. Biofilm experiments confirmed the compound caused a significant decrease in biomass (−97% and thickness (−50%, and it induced a migration activity of the peritrichous flagellated P. putida over the polycarbonate surface not amenable to a biofilm phenotype. The low octanol-water partitioning coefficient and the high water solubility suggested a low bioaccumulation potential and the water compartment as its main environmental recipient and capacitor. Preliminary ecotoxicological tests did not highlight direct toxicity effects toward Daphnia magna. For green algae Pseudokirchneriella subcapitata an effect was observed at concentrations above 100 mg/L with a significant growth of protozoa that may be connected to a concurrent algal growth inhibition.

Polycarbonate-Based Blends for Optical Non-linear Applications

Science.gov (United States)

Stanculescu, F.; Stanculescu, A.

2016-02-01

This paper presents some investigations on the optical and morphological properties of the polymer (matrix):monomer (inclusion) composite materials obtained from blends of bisphenol A polycarbonate and amidic monomers. For the preparation of the composite films, we have selected monomers characterised by a maleamic acid structure and synthesised them starting from maleic anhydride and aniline derivatives with -COOH, -NO2, -N(C2H5)2 functional groups attached to the benzene ring. The composite films have been deposited by spin coating using a mixture of two solutions, one containing the matrix and the other the inclusion, both components of the composite system being dissolved in the same solvent. The optical transmission and photoluminescence properties of the composite films have been investigated in correlation with the morphology of the films. The scanning electron microscopy and atomic force microscopy have revealed a non-uniform morphology characterised by the development of two distinct phases. We have also investigated the generation of some optical non-linear (ONL) phenomena in these composite systems. The composite films containing as inclusions monomers characterised by the presence of one -COOH or two -NO2 substituent groups to the aromatic nucleus have shown the most intense second-harmonic generation (SHG). The second-order optical non-linear coefficients have been evaluated for these films, and the effect of the laser power on the ONL behaviour of these materials has also been emphasised.

Sensory Pollution from Bag Filters, Carbon Filters and Combinations

DEFF Research Database (Denmark)

Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

2008-01-01

by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter...... that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC...

Effect of dietary zinc deficiency on the endogenous phosphorylation and dephosphorylation of rat erythrocyte membrane

International Nuclear Information System (INIS)

Paterson, P.G.; Allen, O.B.; Bettger, W.J.

1987-01-01

The effect of dietary zinc deficiency on patterns of phosphorylation and dephosphorylation of rat erythrocyte membrane proteins and erythrocyte filterability was examined. Weanling male Wistar rats were fed an egg white-based diet containing less than 1.1 mg zinc/kg diet ad libitum for 3 wk. Control rats were either pair-fed or ad libitum-fed the basal diet supplemented with 100 mg zinc/kg diet. Net phosphorylation and dephosphorylation of erythrocyte membrane proteins were carried out by an in vitro assay utilizing [gamma- 32 P]ATP. The membrane proteins were subsequently separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the 32 P content of gel slices was counted by Cerenkov counting. Erythrocyte filterability was measured as the filtration time of suspensions of erythrocytes, both untreated and preincubated with diamide, under constant pressure. Erythrocyte ghosts from zinc-deficient rats demonstrated greater dephosphorylation of protein bands R1 plus R2 and R7 than pair-fed rats and greater net phosphorylation of band R2.2 than pair-fed or ad libitum-fed control rats (P less than 0.05). Erythrocytes from ad libitum-fed control rats showed significantly longer filtration times than those from zinc-deficient or pair-fed control rats. In conclusion, dietary zinc deficiency alters in vitro patterns of erythrocyte membrane protein phosphorylation and dephosphorylation, whereas the depression in food intake associated with the zinc deficiency increases erythrocyte filterability. 71 references

Hydrophilicity and morphological investigation of polycarbonate irradiated by ArF excimer laser

Energy Technology Data Exchange (ETDEWEB)

Jaleh, B. [Bu-Ali-Sina University, Physics Department, Postal Code 65174, Hamedan (Iran, Islamic Republic of)], E-mail: jaleh@basu.ac.ir; Parvin, P. [Amir Kabir University of Technology, Physics Department, P.O. Box: 15875-4413, Tehran (Iran, Islamic Republic of); Laser Research Center, AEOI, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Sheikh, N. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, Tehran (Iran, Islamic Republic of); Zamanipour, Z. [Laser Research Center, AEOI, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Sajad, B. [Azzahra University, Physics Department, Tehran (Iran, Islamic Republic of)

2007-12-15

Lasers are used to modify polymeric materials. In this work, a number of polycarbonate (PC) pieces were exposed by ArF excimer laser, 193 nm, at various UV doses from 10 to 100 J/cm{sup 2} with 50-500 mJ/pulse at 10 Hz pulse repetition rate. Morphology of PC has been investigated by scanning electron microscope (SEM) at three regimes pre-ablation, slow and fast ablation. SEM identifies that the conical defects are created on the polymer surface to grow opposite to the direction of laser irradiation. It increases the superficial absorptivity of the material dependent on the ArF laser induced conical microstructure geometry. The contact angle measurement was performed here, in order to determine the hydrophilicity of the irradiated polymer at various coherent doses. It is shown that the contact angle of PC samples which are exposed to the ArF laser significantly alters with UV dose below 7 J/cm{sup 2}.

Assessment of the viscoelastic mechanical properties of polycarbonate urethane for medical devices.

Science.gov (United States)

Beckmann, Agnes; Heider, Yousef; Stoffel, Marcus; Markert, Bernd

2018-06-01

The underlying research work introduces a study of the mechanical properties of polycarbonate urethane (PCU), used in the construction of various medical devices. This comprises the discussion of a suitable material model, the application of elemental experiments to identify the related parameters and the numerical simulation of the applied experiments in order to calibrate and validate the mathematical model. In particular, the model of choice for the simulation of PCU response is the non-linear viscoelastic Bergström-Boyce material model, applied in the finite-element (FE) package Abaqus®. For the parameter identification, uniaxial tension and unconfined compression tests under in-laboratory physiological conditions were carried out. The geometry of the samples together with the applied loadings were simulated in Abaqus®, to insure the suitability of the modelling approach. The obtained parameters show a very good agreement between the numerical and the experimental results. Copyright © 2018 Elsevier Ltd. All rights reserved.

Factors affecting the adhesion of microwave plasma deposited siloxane films on polycarbonate

International Nuclear Information System (INIS)

Muir, B.W.; Thissen, H.; Simon, G.P.; Murphy, P.J.; Griesser, H.J.

2006-01-01

The effects of a radiofrequency oxygen plasma pretreatment and residual water content in the substrate on the adhesion of microwave plasma deposited tetramethyldisiloxane thin films on Bisphenol-A polycarbonate (BPA-PC) were investigated. Samples were characterised using a crosshatch adhesion test, optical and electron microscopy, and X-ray photoelectron spectroscopy. It was found that the use of a low power (5 W) and low treatment time (0.1 s) oxygen plasma can improve adhesion while greater treatment times (1-30 s) and higher oxygen plasma powers (40 W) resulted in a decreased level of adhesion. In addition, it was shown that a BPA-PC water content greater than 90 ppm resulted in rapid adhesion failure of deposited films at the substrate-plasma polymer interface during outdoor weathering. All films degraded substantially when exposed to environmental weathering, indicating ageing reactions within the plasma polymer films themselves, and at the bulk polymer-coating interface

Refining of biodiesel by ceramic membrane separation

Energy Technology Data Exchange (ETDEWEB)

Wang, Yong; Ou, Shiyi; Tan, Yanlai; Tang, Shuze [Department of Food Science and Engineering, Jinan University, Guangzhou 510632 (China); Wang, Xingguo; Liu, Yuanfa [School of Food Science and Technology, Jiangnan University, Wuxi 214112 (China)

2009-03-15

A ceramic membrane separation process for biodiesel refining was developed to reduce the considerable usage of water needed in the conventional water washing process. Crude biodiesel produced by refined palm oil was micro-filtered by ceramic membranes of the pore size of 0.6, 0.2 and 0.1 {mu}m to remove the residual soap and free glycerol, at the transmembrane pressure of 0.15 MPa and temperature of 60 C. The flux through membrane maintained at 300 L m{sup -} {sup 2} h{sup -} {sup 1} when the volumetric concentrated ratio reached 4. The content of potassium, sodium, calcium and magnesium in the whole permeate was 1.40, 1.78, 0.81 and 0.20 mg/kg respectively, as determined by inductively coupled plasma-atomic emission spectroscopy. These values are lower than the EN 14538 specifications. The residual free glycerol in the permeate was estimated by water extraction, its value was 0.0108 wt.%. This ceramic membrane technology was a potential environmental process for the refining of biodiesel. (author)

Antibacterial performance of nano polypropylene filter media containing nano-TiO{sub 2} and clay particles

Energy Technology Data Exchange (ETDEWEB)

Shafiee, Sara; Zarrebini, Mohammad; Naghashzargar, Elham, E-mail: e.naghashzargar@tx.iut.ac.ir; Semnani, Dariush, E-mail: d-semnani@cc.iut.ac.ir [Isfahan University of Technology, Department of Textile Engineering (Iran, Islamic Republic of)

2015-10-15

Disinfection and elimination of pathogenic microorganisms from liquid can be achieved by filtration process using antibacterial filter media. The advent of nanotechnology has facilitated the introduction of membranes consisting of nano-fiber in filtration operations. The melt electro-spun fibers due to their extremely small diameters are used in the production of this particular filtration medium. In this work, antibacterial polypropylene filter medium containing clay particles and nano-TiO{sub 2} were made using melt electro-spun technology. Antibacterial performance of polypropylene nano-filters was evaluated using E. coli bacteria. Additionally, filtration efficiency of the samples in terms fiber diameter, filter porosity, and fiber distribution using image processing technique was determined. Air permeability and dust aerosol tests were conducted to establish the suitability of the samples as a filter medium. It was concluded that as far as antibacterial property is concerned, nano-fibers filter media containing clay particles are preferential to similar media containing TiO{sub 2} nanoparticles.

High-density near-field optical disc recording using phase change media and polycarbonate substrate

Science.gov (United States)

Shinoda, Masataka; Saito, Kimihiro; Ishimoto, Tsutomu; Kondo, Takao; Nakaoki, Ariyoshi; Furuki, Motohiro; Takeda, Minoru; Akiyama, Yuji; Shimouma, Takashi; Yamamoto, Masanobu

2004-09-01

We developed a high density near field optical recording disc system with a solid immersion lens and two laser sources. In order to realize the near field optical recording, we used a phase change recording media and a molded polycarbonate substrate. The near field optical pick-up consists of a solid immersion lens with numerical aperture of 1.84. The clear eye pattern of 90.2 GB capacity (160nm track pitch and 62 nm per bit) was observed. The jitter using a limit equalizer was 10.0 % without cross-talk. The bit error rate using an adaptive PRML with 8 taps was 3.7e-6 without cross-talk. We confirmed that the near field optical disc system is a promising technology for a next generation high density optical disc system.

Acetal Resins, Acrylic & Modacrylic Fibers, Carbon Black, Hydrogen Fluoride, Polycarbonate, Ethylene, Spandex & Cyanide Chemical Manufacturing: NESHAP for Source Categories, Generic Maximum Achievable Control Technology Standards (40 CFR 63, Subpart YY)

Science.gov (United States)

Learn about the NESHAP for GMACT for acetal resins, hydrogen fluoride, polycarbonate, ethylene production and cyanide chemicals. Find the rule history information, federal register citations, legal authority, rule summary, and additional resources

Ion exchange filter transition plan for BWRs and PWRs

International Nuclear Information System (INIS)

Garcia, Susan; McElrath, Joel; Varnam, Jeremie; Giannelli, Joseph F.

2014-01-01

Analysis and quantification of reactor water, feedwater, and chemical and volume control system (CVCS) soluble metals and radioisotopes are essential for monitoring species that impact fuel performance, steam generator and heat exchanger performance, mitigation of stress corrosion cracking of reactor piping and internals, radiation fields and ensuring that dose mitigation techniques are effective. Soluble species in the CVCS, feedwater, reactor water and other process sample streams are usually collected on ion exchange membranes after the sample has passed through a 0.45 or 0.1 μm membrane filter. Cationic species are predominantly of interest. Most nuclear plants currently use cation exchange membranes from Toray Industries, Inc. In September 2012, it was reported that Toray Industries, Inc. would discontinue the manufacturing of cation exchange membranes at the end of 2012. Similar reports were received concerning ion exchange membranes manufactured by Pall Corporation. These reports prompted several plants and utilities to begin evaluating other products from various vendors to replace their current ion exchange membranes in preparation for a transition. With this possible change having a potential impact on the water chemistry analyses that are important for monitoring fuel reliability and corrosion and dose control, an initial scoping evaluation of ion exchange membrane availability from various vendor and plant experiences was conducted. Recommended approaches were provided to close identified gaps and reduce burden on nuclear plant chemistry laboratories. Additional work required in 2014, includes an independent laboratory review of membrane performance and in-plant demonstrations. These demonstrations and evaluations will assist the industry by providing the technical input needed to manage a change in membrane use so that preferred processes and media can be identified to minimize any adverse impacts on chemistry analyses that support chemistry control

A bezel of an automotive headlamp: scrap/virgin ratio effects on its physicochemical properties due to the use of recycled polycarbonate

OpenAIRE

Vega, Etzail; González-Calderón, J. A.; Villegas, Antonio; Montiel, Raúl; Pérez, Elías; Vallejo-Montesinos, Javier

2016-01-01

Abstract: Automotive bezels of polycarbonate (PC) were prepared in this work by varying the amount of recycled polymer in order to estimate an acceptable scrap/virgin ratio that maintains the material properties. Conducted tests allow us to define the limit to don't compromise the performance of recycled pieces. The studied properties were their chemical structure, molecular weight distribution, mechanical and surface properties of the samples. Results showed no change in the chemical structu...

A study of AFM-based scratch process on polycarbonate surface and grating application

International Nuclear Information System (INIS)

Choi, Chul Hyun; Lee, Dong Jin; Sung, Jun-Ho; Lee, Min Woo; Lee, Seung-Gol; Park, Se-Geun; Lee, El-Hang; O, Beom-Hoan

2010-01-01

We report on the possibility of applying atomic force microscope (AFM) lithography to draw micro/nano-structures on the surface of a polycarbonate (PC) substrate. We also fabricated a grating structure on the PC surface using the scratch method. An AFM silicon tip coated with a diamond layer was utilized as a cutting tool to scratch the surface of the sample. In order to obtain pattern depth deeper than the control method of interaction force, we used a scanner movement method which the sample scanner moves along the Z-axis. A grating of 100 μm x 150 μm was fabricated by the step and repeat method wherein the sample stage is moved in the direction of the XY-axis. The period and the depth of the grating are 500 and 50 nm, respectively. Light of 632.8 nm wavelength was diffracted on the surface of the PC substrate.

Filter arrays

Science.gov (United States)

Page, Ralph H.; Doty, Patrick F.

2017-08-01

The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

Cobalt and organics removal effect using fiber filter/reverse osmosis combination process for LLRW from korean PWR NPP

International Nuclear Information System (INIS)

Park, S.M.; Yang, H.Y.; Song, M.J.

2001-01-01

Evaporation system for liquid radioactive waste process has been used in Korean PWR nuclear power plants. The system is the most desirable process for decontamination factor (DF) theoretically. However, during the operation of the system, various problems have been arising such as scaling, carry over, etc. Because these problems make DF low, advanced technologies for liquid radwaste process have been world widely developed instead of keeping evaporation system. The main goal of new technologies is ALARA, ease of operation, cost effectiveness and minimization of environmental effect. Korea Electric Power Corporation is currently developing a combined treatment process for liquid radwaste using Micro-filter, Ultra-filter, Reverse Osmosis (RO) membrane, etc for the purpose of partly enhancement of evaporator and of having an alternative liquid radwaste process system for new reactors. As a part of the above project, the feasibility study using the Rolled Fiber-Filter (RFF) and RO membrane has been carried out. This paper reports the results of lab-test from the combined process of the fiber filtration and RO membrane module for cobalt and organics removal. The study was especially focused on the boric acid permeation in the RO unit. Because boric acid occupies large volume of the final waste after evaporation process, the new technology such as RO process has to be studied on the boron process. (author)

Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

Science.gov (United States)

Poinern, Gerrard Eddy Jai; Ali, Nurshahidah; Fawcett, Derek

2011-01-01

The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering. PMID:28880002

Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development.

Science.gov (United States)

Poinern, Gerrard Eddy Jai; Ali, Nurshahidah; Fawcett, Derek

2011-02-25

The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

Directory of Open Access Journals (Sweden)

Gerrard Eddy Jai Poinern

2011-02-01

Full Text Available The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

Probing the role of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) -coated multiwalled carbon nanotubes in the thermal and mechanical properties of polycarbonate nanocomposites

KAUST Repository

Zhou, Jian

2014-03-05

The role played by multiwalled carbon nanotubes (MWCNTs) coated with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) in the thermal and mechanical properties of polycarbonate (PC) nanocomposites was analyzed. We used differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) to demonstrate that the glass transition temperature of polycarbonate nanocomposites decreased whereas the storage modulus of the samples increased by including PEDOT/PSS-coated MWCNTs. These results indicated that PEDOT/PSS acts as an antiplasticizer. We attributed the enhancement of the storage modulus to the strong hydrogen bonding between PSS and the PC matrix and the reduction of the free volume in the PC matrix due to the shrinkage of PEDOT/PSS upon heating. We also investigated changes in the thermal conductivity and thermal degradation behavior of the nanocomposites. The results indicated that PEDOT/PSS did not play a significant role in improving the thermal conductivity and thermal stability of PC nanocomposites. The relative improvements in the conductivity and thermal stability of the samples that contained PEDOT/PSS were attributed to the better dispersion of the MWCNTs in the PC matrix. © 2014 American Chemical Society.

Separation/preconcentration of silver(I) and lead(II) in environmental samples on cellulose nitrate membrane filter prior to their flame atomic absorption spectrometric determinations

International Nuclear Information System (INIS)

Soylak, Mustafa; Cay, Rukiye Sungur

2007-01-01

An enrichment method for trace amounts of Ag(I) and Pb(II) has been established prior to their flame atomic absorption spectrometric determinations. The preconcentration/separation procedure is based on chelate formation of Ag(I) and Pb(II) with ammonium pyrrolidine dithiocarbamate (APDC) and on retention of the chelates on cellulose nitrate membrane filter. The influences of some analytical parameters including pH and amounts of reagent, etc. on the recoveries of analytes were investigated. The effects of interferic ions on the quantitative recoveries of analytes were also examined. The detection limits (k = 3, N = 11) were 4.6 μg L -1 for silver(I) and 15.3 μg L -1 for lead(II). The relative standard deviations (R.S.D.) of the determinations for analyte ions were below 3%. The method was applied to environmental samples for the determination of analyte ions with satisfactory results (recoveries >95%)

All-in-one nanowire-decorated multifunctional membrane for rapid cell lysis and direct DNA isolation.

KAUST Repository

So, Hongyun; Lee, Kunwoo; Murthy, Niren; Pisano, Albert P

2014-01-01

This paper describes a handheld device that uses an all-in-one membrane for continuous mechanical cell lysis and rapid DNA isolation without the assistance of power sources, lysis reagents, and routine centrifugation. This nanowire-decorated multifunctional membrane was fabricated to isolate DNA by selective adsorption to silica surface immediately after disruption of nucleus membranes by ultrasharp tips of nanowires for a rapid cell lysis, and it can be directly assembled with commercial syringe filter holders. The membrane was fabricated by photoelectrochemical etching to create microchannel arrays followed by hydrothermal synthesis of nanowires and deposition of silica. The proposed membrane successfully purifies high-quality DNA within 5 min, whereas a commercial purification kit needs more than an hour.

All-in-one nanowire-decorated multifunctional membrane for rapid cell lysis and direct DNA isolation.

KAUST Repository

So, Hongyun

2014-11-24

This paper describes a handheld device that uses an all-in-one membrane for continuous mechanical cell lysis and rapid DNA isolation without the assistance of power sources, lysis reagents, and routine centrifugation. This nanowire-decorated multifunctional membrane was fabricated to isolate DNA by selective adsorption to silica surface immediately after disruption of nucleus membranes by ultrasharp tips of nanowires for a rapid cell lysis, and it can be directly assembled with commercial syringe filter holders. The membrane was fabricated by photoelectrochemical etching to create microchannel arrays followed by hydrothermal synthesis of nanowires and deposition of silica. The proposed membrane successfully purifies high-quality DNA within 5 min, whereas a commercial purification kit needs more than an hour.

Digital Simulation of a Hybrid Active Filter - An Active Filter in Series with a Shunt Passive Filter

OpenAIRE

Sitaram, Mahesh I; Padiyar, KR; Ramanarayanan, V

1998-01-01

Active filters have long been in use for the filtering of power system load harmonics. In this paper, the digital simulation results of a hybrid active power filter system for a rectifier load are presented. The active filter is used for filtering higher order harmonics as the dominant harmonics are filtered by the passive filter. This reduces the rating of the active filter significantly. The DC capacitor voltage of the active filter is controlled using a PI controller.

Rheology, Morphology and Temperature Dependency of Nanotube Networks in Polycarbonate/Multiwalled Carbon Nanotube Composites

International Nuclear Information System (INIS)

Abbasi, Samaneh; Carreau, Pierre J.; Derdouri, Abdessalem

2008-01-01

We present several issues related to the state of dispersion and rheological behavior of polycarbonate/multiwalled carbon nanotube (MWCNT) composites. The composites were prepared by diluting a commercial masterbatch containing 15 wt% nanotubes using optimized melt-mixing conditions. The state of dispersion was then analyzed by scanning and transmission electron microscopy (SEM, TEM). Rheological characterization was also used to assess the final morphology. Further, it was found that the rheological percolation threshold decreased significantly with increasing temperature and finally reached a constant value. This is described in terms of the Brownian motion, which increases with temperature. However, by increasing the nanotube content, the temperature effects on the complex viscosity at low frequency decreased significantly. Finally, the percolation thresholds were found to be approximately equal to 0.3 and 2 wt% for rheological and electrical conductivity measurements, respectively

EM Task 9 - Centrifugal Membrane Filtration

International Nuclear Information System (INIS)

Stevens, B.G.; Stepan, D.J.; Hetland, M.D.

1998-01-01

This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities

Cellulose membrane modified with polypyrrole as an extraction device for the determination of emerging contaminants in river water with GC-MS.

Science.gov (United States)

de Noronha, Bárbara Viero; Bergamini, Márcio Fernando; Marcolino Junior, Luiz Humberto; da Silva, Bruno José Gonçalves

2018-05-21

In this study, a simple, efficient, and reusable device based on cellulose membranes modified with polypyrrole was developed to extract 14 emerging contaminants from aqueous matrices. For chemical polymerization, a low-cost cellulose membrane was immersed in 0.1 mol L -1 pyrrole and 0.5 mol L -1 ammonium persulfate for 40 min in an ice/water bath. The cellulose membranes modified with polypyrrole were accommodated in a polycarbonate holder suitable for solid-phase extraction disks. Solid-phase extraction parameters that affect extraction efficiency, such as sample volume, pH, flow-rate, and desorption were optimized. Subsequently, determination of target compounds was performed by gas chromatography with mass spectrometry. The linear range for analytes ranged from 0.05 to 500 μg L -1 , with coefficients of determination above 0.990. The limits of quantification varied between 0.05 and 10 μg L -1 , with relative standard deviations lower than 17%. The performance of the proposed cellulose membranes modified with polypyrrole device for real samples was evaluated after extraction of emerging contaminants from a river water sample from the city of Curitiba-Brazil. Bisphenol A (6.39 μg L -1 ), caffeine (17.83 μg L -1 ), and paracetamol (19.28 μg L -1 ) were found in these samples. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Treatment of car wash wastewater by UF membranes

Science.gov (United States)

Istirokhatun, Titik; Destianti, Puti; Hargianintya, Adenira; Oktiawan, Wiharyanto; Susanto, Heru

2015-12-01

The existence of car wash service facilitates car owners to remove dirt and grime from their vehicles. However, the dirt washed off vehicles as well as the cleaning materials themselves may be harmful to the environment if they are not properly managed and discharged. Many technologies have been proposed to treat car wash wastewater such as coagulation flocculation, tricking filter and flocculation-flotation. Nevertheless, these technologies have low efficiency to eliminate oil and small organic compounds. Ultrafiltration (UF) membranes were used in this study to treat car wash wastewater. This study investigated the performance of UF membranes under various pressures to remove COD, oil and grease, and also turbidity from car wash waste water. The membrane performance was examined by investigation of permeate flux and membrane rejection. The results meet the standard of environmental regulation and it is possible to be reused. The highest rejection was shown by PES10 (polyethersulfone 10 kDa) in 1 bar operation with complete rejection for both turbidity and oil and grace and 95% rejection for COD.

Embryo Cell Membranes Reconstruction by Tensor Voting

OpenAIRE

Michelin , Gaël; Guignard , Léo; Fiuza , Ulla-Maj; Malandain , Grégoire

2014-01-01

International audience; Image-based studies of developing organs or embryos produce a huge quantity of data. To handle such high-throughput experimental protocols, automated computer-assisted methods are highly desirable. This article aims at designing an efficient cell segmentation method from microscopic images. The proposed approach is twofold: first, cell membranes are enhanced or extracted by the means of structure-based filters, and then perceptual grouping (i.e. tensor voting) allows t...

Frictional and Optical Properties of Diamond-Like-Carbon Coatings on Polycarbonate

International Nuclear Information System (INIS)

Lin Zeng; Gao Ding; Ba Dechun; Wang Feng; Liu Chunming

2013-01-01

In this work, diamond-like-carbon (DLC) films were deposited onto polycarbonate (PC) substrates by radio-frequency plasma-enhanced chemical vapor deposition (RF PECVD), and silicon films were prepared between DLC and PC substrates by magnetron sputtering deposition so as to improve the adhesion of the DLC films. The deposited films were investigated by means of field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Subsequently, the following frictional and optical properties of the films were measured: the friction coefficient by using a ball-on-disk tribometer, the scratch hardness by using a nano-indenter, the optical transmittance by using a UV/visible spectrometer. The effects of incident power upon the frictional and optical properties of the films were investigated. Films deposited at low incident powers showed large optical gaps, which decreased with increasing incident power. The optical properties of DLC films correlated to the sp 2 content of the coatings. High anti-scratch properties were obtained at higher values of incident power. The anti-scratch properties of DLC films correlated to the sp 3 content of the coatings

ANAEROBIC MEMBRANE BIOREACTORS FOR DOMESTIC WASTEWATER TREATMENT. PRELIMINARY STUDY

Directory of Open Access Journals (Sweden)

Luisa Vera

2014-12-01

Full Text Available The operation of submerged anaerobic membrane bioreactors (SAnMBRs for domestic wastewaters treatment was studied in laboratory scale, with the objective to define sustainable filtration conditions of the suspensions along the process. During continuous experiments, the organic matter degradation by anaerobic way showed an average DQOT removal of 85% and 93%. Indeed, the degradation generated biogas after 12 days of operation and its relative methane composition was of 60% after 25 days of operation. Additionally, the comparison between membrane bioreactors (MBRs performance in aerobic and anaerobic conditions in filterability terms, reported that both systems behave similarly once reached the stationary state.

Filter assembly for metallic and intermetallic tube filters

Science.gov (United States)

Alvin, Mary Anne; Lippert, Thomas E.; Bruck, Gerald J.; Smeltzer, Eugene E.

2001-01-01

A filter assembly (60) for holding a filter element (28) within a hot gas cleanup system pressure vessel is provided, containing: a filter housing (62), said filter housing having a certain axial length and having a peripheral sidewall, said sidewall defining an interior chamber (66); a one piece, all metal, fail-safe/regenerator device (68) within the interior chamber (66) of the filter housing (62) and/or extending beyond the axial length of the filter housing, said device containing an outward extending radial flange (71) within the filter housing for seating an essential seal (70), the device also having heat transfer media (72) disposed inside and screens (80) for particulate removal; one compliant gasket (70) positioned next to and above the outward extending radial flange of the fail-safe/regenerator device; and a porous metallic corrosion resistant superalloy type filter element body welded at the bottom of the metal fail-safe/regenerator device.

Dust collected in air filters - Possible source of volatile organic compounds and particles; Ger smutsiga luftfilter foersaemrad tilluft ? En studie av emissioner med ursprung i filter

Energy Technology Data Exchange (ETDEWEB)

Johansson, J.H.P.; Rosell, Lars

1998-06-01

Emissions from dust collected in air filters have been investigated using in situ measurements. Two air filters of different classes (F6 and F8/9) have been exposed to outdoor air for a preconditioning period of six months. After this period measurements have been carried out using two operating conditions, continuous and intermittent. Air samples were taken both up- and downstream of the filters. The air samples were analysed regarding volatile organic compounds (VOCs), including formaldehyde and microbial VOCs (mVOC) and the samples of airborne dust were examined regarding the contents of colony forming units, ergosterol (marker of fungi), and endotoxin (marker of gram negative bacteria). Furthermore, a visual inspection of the airborne dust was conducted using SEM. Particles released when the fan was turned on and a short period after, were monitored using an optical particle counter, slitsamplers (fungus spores) and membrane filters for SEM analysis. After finishing the in situ measurements, the filters were placed in climate chambers for emission sampling. Finally, samples were cut out for analysis of microbial contents in the filter material, both on the dusty and `clean` side of the filters. No consistent change of VOC, aldehyde or mVOC concentrations across the filters could be measured. A significant ozone reduction was seen in one of the in situ measurements. The chamber experiments showed that the filters were a source of various VOCs, e.g. aldehydes and mVOCs. The emission of mVOCs in the chambers was significantly higher for the F8/9 filter, probably due to more and finer dust in that filter. Only a few colonization units (fungi) penetrate filters when running continuously but an increase was noted at the moment the fans were started. The same phenomenon was observed with the optical particle counter, but both the intensity and length of the increase, for colonization units and other particles, were moderate. Mycological examination of the filter

Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

Directory of Open Access Journals (Sweden)

Juan G. Gonzalez

2002-01-01

Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the α-stable and generalized-t. We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the “normal” equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

Filter material charging apparatus for filter assembly for radioactive contaminants

International Nuclear Information System (INIS)

Goldsmith, J.M.; O'Nan, A. Jr.

1977-01-01

A filter charging apparatus for a filter assembly is described. The filter assembly includes a housing with at least one filter bed therein and the filter charging apparatus for adding filter material to the filter assembly includes a tank with an opening therein, the tank opening being disposed in flow communication with opposed first and second conduit means, the first conduit means being in flow communication with the filter assembly housing and the second conduit means being in flow communication with a blower means. Upon activation of the blower means, the blower means pneumatically conveys the filter material from the tank to the filter housing

Aligned nanowire growth using lithography-assisted bonding of a polycarbonate template for neural probe electrodes

International Nuclear Information System (INIS)

Yoon, Hargsoon; Deshpande, Devesh C; Ramachandran, Vasuda; Varadan, Vijay K

2008-01-01

This research presents a fabrication method of vertically aligned nanowires on substrates using lithography-assisted template bonding (LATB) towards developing highly efficient electrodes for biomedical applications at low cost. A polycarbonate template containing cylindrical nanopores is attached to a substrate and the nanopores are selectively opened with a modified lithography process. Vertically aligned nanowires are grown by electrochemical deposition through these open pores on polyimide film and silicon substrates. The process of opening the nanopores is optimized to yield uniform growth of nanowires. The morphological, crystalline, and electrochemical properties of the resulting vertically aligned nanowires are discussed using scanning electron microscopy (SEM), x-ray diffraction (XRD), and electrochemical analysis tools. The potential application of this simple and inexpensive fabrication technology is discussed in the development of neural probe electrodes

Building blocks of temporal filters in retinal synapses.

Directory of Open Access Journals (Sweden)

Bongsoo Suh

2014-10-01

Full Text Available Sensory systems must be able to extract features of a stimulus to detect and represent properties of the world. Because sensory signals are constantly changing, a critical aspect of this transformation relates to the timing of signals and the ability to filter those signals to select dynamic properties, such as visual motion. At first assessment, one might think that the primary biophysical properties that construct a temporal filter would be dynamic mechanisms such as molecular concentration or membrane electrical properties. However, in the current issue of PLOS Biology, Baden et al. identify a mechanism of temporal filtering in the zebrafish and goldfish retina that is not dynamic but is in fact a structural building block-the physical size of a synapse itself. The authors observe that small, bipolar cell synaptic terminals are fast and highly adaptive, whereas large ones are slower and adapt less. Using a computational model, they conclude that the volume of the synaptic terminal influences the calcium concentration and the number of available vesicles. These results indicate that the size of the presynaptic terminal is an independent control for the dynamics of a synapse and may reveal aspects of synaptic function that can be inferred from anatomical structure.

PEMBUATAN MEMBRAN ULTRAFILTRASI DARI POLIMER SELULOSA ASETAT DENGAN METODE INVERSI FASA

Directory of Open Access Journals (Sweden)

Agus Mirwan

2017-04-01

Full Text Available Clean water treatment with membrane technology is a water treatment process with very good quality and suitable for drinking water treatment in developing countries because the membrane has a lot of advantages. One type of membrane separation operation is with ultrafiltration membranes. Ultrafiltration is a process of filtering particles in the size range of colloids, namely liquid while large molecules detained on the surface of the membrane and the solute with very small size can pass through the membrane. The purpose of this study was to determine the best composition of %wt of dimethylformamide in the manufacture of ultrafiltration membranes. Ultrafiltration membrane is made by varying the concentration of the additive of dimethylformamide which serves for the determination of membrane pore size and the concentration of acetone. Mixing materials done by stirring for ± 6 hours, polymer film printouts is coagulated for 1 hour in ice water (± 4 ° C and then washed with running water and stored in a container containing formalin. Then conducted testing on the membrane using peat water where permeate that generated is measured the volume of each interval of 5 minutes to determine the membrane flux. Then analyzing the concentration of permeate to determine the coefficient of rejection, where the expected rejection is> 90%. Based on the research results, the best ultrafiltration membrane was membrane with composition wt% of dimethylformamide of 20; 24 and 28, where rejection coefficient average respectively was 98.15; 92.80 and 95.41%.

Crude biodiesel refining using membrane ultra-filtration process: An environmentally benign process

Directory of Open Access Journals (Sweden)

I.M. Atadashi

2015-12-01

Full Text Available Ceramic membrane separation system was developed to simultaneously remove free glycerol and soap from crude biodiesel. Crude biodiesel produced was ultra-filtered by multi-channel tubular membrane of the pore size of 0.05 μm. The effects of process parameters: transmembrane pressure (TMP, bar, temperature (°C and flow rate (L/min on the membrane system were evaluated. The process parameters were then optimized using Central Composite Design (CCD coupled with Response Surface Methodology (RSM. The best retention coefficients (%R for free glycerol and soap were 97.5% and 96.6% respectively. Further, the physical properties measured were comparable to those obtained in ASTMD6751-03 and EN14214 standards.

Plasmonic and Photonic Modes Excitation in Graphene on Silicon Photonic Crystal Membrane

DEFF Research Database (Denmark)

Andryieuski, Andrei; Gu, Tingyi; Hao, Yufeng

. Being deposited on a silicon photonic crystal membrane graphene serves as a highly promising system for modern optoelectronics with rich variety of possible regimes. Depending on the relation between the photonic crystal lattice constant and wavelengths (plasmonic, photonic and free-space) we identify...... characterization. Measured data are well correlated with the numerical analysis. Combined graphene – silicon photonic crystal membranes can find applications for infrared absorbers, modulators, filters, sensors and photodetectors....... four different interaction schemes. We refer to them as metamaterial, plasmonic, photonic and diffraction grating regimes based on the principle character of light interactions with the graphene deposited on the Si photonic crystal membrane. The optimal configurations for resonant excitation of modes...