CO tolerance of polymer electrolyte fuel cells

Energy Technology Data Exchange (ETDEWEB)

Gubler, L; Scherer, G G; Wokaun, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Reformed methanol can be used as a fuel for polymer electrolyte fuel cells instead of pure hydrogen. The reformate gas contains mainly H{sub 2}, CO{sub 2} in the order of 20% and low levels of CO in the order of 100 ppm. CO causes severe voltage losses due to poisoning of the anode catalyst. The effect of CO on cell performance was investigated at different CO levels up to 100 ppm. Various options to improve the CO tolerance of the fuel cell were assessed thereafter, of which the injection of a few percents of oxygen into the fuel feed stream proved to be most effective. By mixing 1% of oxygen with hydrogen containing 100 ppm CO, complete recovery of the cell performance could be attained. (author) 2 figs., 2 tabs., 3 refs.

Photochemical stability of conjugated polymers, electron acceptors and blends for polymer solar cells resolved in terms of film thickness and absorbance

DEFF Research Database (Denmark)

Tromholt, Thomas; Vesterager Madsen, Morten; Carlé, Jon Eggert

2012-01-01

Photochemical degradation at 1 sun under AM1.5G illumination was performed on six conjugated polymers and five different electron acceptors. Additionally, the respective polymer:PC60BM and P3HT:electron acceptor blends were studied, and all degradations were resolved in terms of film thickness...... within each material group were found to vary for both the pure polymers and the blends. The stability ranking between the materials of the pure polymers was found to be similar to the ranking for their respective blends, implying that the photochemical stability of a pure polymer is a good measure...... of its associated blend stability. Different electron acceptors were found to stabilize P3HT decreasingly with decreasing donor–acceptor LUMO–LUMO gap. Destabilization of P3HT was observed in the case of the electron acceptor ICBA. Additionally, the decreased stabilization of P3HT by high LUMO electron...

PIV measurement of turbulent mixing layer flow with polymer additives

International Nuclear Information System (INIS)

Ning, T; Guo, F; Chen, B; Zhang, X

2009-01-01

Turbulent mixing layer flow with polymer additives was experimentally investigated by PIV in present paper. The velocity ratio between high and low speed is 4:1 and the Reynolds number for pure water case based on the velocity differences of two steams and hydraulic diameter of the channel ranges from 14667∼73333. Flow field and turbulent quantities of turbulent mixing layer with 200ppm polymer additives were measured and compared with pure water mixing layer flow. It is shown that the dynamic development of mixing layer is greatly influenced by polymer addictives. The smaller vortices are eliminated and the coherent structure is much clearer. Similar with pure water case, Reynolds stress and vorticity still concentrate in a coniform area of central part of mixing layer and the width will increase with the Reynolds number increasing. However, compared with pure water case, the coniform width of polymer additives case is larger, which means the polymer additives will lead to the diffusion of coherent structure. The peak value of vorticity in different cross section will decrease with the development of mixing layer. Compared with pure water case, the vorticity is larger at the beginning of the mixing layer but decreases faster in the case with polymer additives.

Graphene-based polymer nanocomposites

NARCIS (Netherlands)

Tkalya, E.

2012-01-01

The main reason for the rapid development of polymer composite materials is that the traditional "pure" polymers have largely played out its performance capabilities whereas technology requires materials with new properties and advances. There are a number of advantages polymeric composites have

Stochastic ice stream dynamics.

Science.gov (United States)

Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

2016-08-09

Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

Laser synthesis of aluminium nanoparticles in biocompatible polymer solutions

Science.gov (United States)

Singh, Rina; Soni, R. K.

2014-08-01

Pulsed laser ablation of Aluminium (Al) in pure water rapidly forms a thin alumina (Al2O3) layer which drastically modifies surface plasmon resonance (SPR) absorption characteristics in deep-UV region. Initially, pure aluminium nanoparticles (NPs) are generated in water without any stabilizers or surfactants at low laser fluence which gradually transform to stable Al-Al2O3 core-shell nanostructure with increasing either residency time or fluence. The role of laser wavelength and fluence on the SPR properties and oxidation characteristics of Al NPs has been investigated in detail. We also present a one-step in situ synthesis of oxide-free stable Al NPs in biocompatible polymer solutions using laser ablation in liquid method. We have used nonionic polymers (PVP, PVA and PEG) and anionic surfactant (SDS) stabilizer to suppress the Al2O3 formation and studied the effect of polymer functional group, polymeric chain length, polymer concentration and anionic surfactant on the incipient embryonic aluminium particles and their sizes. The different functional groups of polymers resulted in different oxidation states of Al. PVP and PVA polymers resulted in pure Al NPs; however, PEG and SDS resulted in alumina-modified Al NPs. The Al nanoparticles capped with PVP, PVA, and PEG show a good correlation between nanoparticle stability and monomeric length of the polymer chain.

Hierarchical porous structured zeolite composite for removal of ionic contaminants from waste streams and effective encapsulation of hazardous waste

Energy Technology Data Exchange (ETDEWEB)

Al-Jubouri, Sama M. [Chemical Engineering & Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Curry, Nicholas A. [Materials Science, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Holmes, Stuart M., E-mail: stuart.holmes@manchester.ac.uk [Chemical Engineering & Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

2016-12-15

A hierarchical structured composite made from clinoptilolite supported on date stones carbon is synthesized using two techniques. The composites are manufactured by fixing a natural zeolite (clinoptilolite) to the porous surface of date stones carbon or by direct hydrothermal synthesis on to the surface to provide a supported high surface area ion-exchange material for metal ion removal from aqueous streams. The fixing of the clinoptilolite is achieved using sucrose and citric acid as a binder. The composites and pure clinoptilolite were compared to test the efficacy for the removal of Sr{sup 2+} ions from an aqueous phase. The encapsulation of the Sr{sup 2+} using either vitrification or a geo-polymer addition was tested to ensure that the hazardous waste can be made safe for disposal. The hierarchical structured composites were shown to achieve a higher ion exchange capacity per gram of zeolite than the pure clinoptilolite (65 mg/g for the pure natural clinoptilolite and 72 mg/g for the pure synthesized clinoptilolite) with the synthesized composite (160 mg/g) having higher capacity than the natural clinoptilolite composite (95 mg/g). The rate at which the equilibria were established followed the same trend showing the composite structure facilitates diffusion to the ion-exchange sites in the zeolite.

How low can you go: Spatial frequency sensitivity in a patient with pure alexia

DEFF Research Database (Denmark)

Starrfelt, Randi; Nielsen, Simon; Habekost, Thomas

2013-01-01

Pure alexia is a selective deficit in reading, following lesions to the posterior left hemisphere. Writing and other language functions remain intact in these patients. Whether pure alexia is caused by a primary problem in visual perception is highly debated. A recent hypothesis suggests that a low...... in the visual processing stream....

Picot-Benoit Effect in Polymer Solutions

Science.gov (United States)

Beaucage, Gregory; Sukumaran, Sathish; Ilavsky, Jan

2003-03-01

SAXS from polymers in solution is well described at intermediate (q = 0.01-0.1 Å-1) scattering vectors by scaling theory which predicts three regimes in concentration: dilute, semi-dilute and concentrated [1-3]. A persistent problem is the appearance of excess scattering at low-q, q molecular weight dependence for these fluctuations in the dilute and semi-dilute regimes. The later is unexpected since above c* scaling theory predicts no M dependencies due to screening [1-3]. The literature associates PB features with semi-dilute and concentrated solutions, yet we have observed excess scattering even in dilute solutions of polystyrene in cyclopentane. 1) de Gennes P-G, Scaling Concepts in Polymer Physics, 1979. 2) Strobl G, The Physics of Polymers, Berlin 1997. 3) Doi M, Introduction to Polymer Physics, Oxford 1997. 4) Benoit H, Picot C Pure Appl. Chem. 12 545 (1966). 5) Benoit H, Picot C Pure Appl. Chem. 12 1271 (1966). 6) Xie Y, et al. Physica A 232 94 (1996). 7) Korberstein JT, et al. Polymer 26 673 (1985). 8) Morfin I, et al. Macromolecules 32 7208 (1999). 9) Blanco CM, et al. Langmuir 16 8585 (2000).

Depletion interactions in two-dimensional colloid-polymer mixtures: molecular dynamics simulations

International Nuclear Information System (INIS)

Kim, Soon-Chul; Seong, Baek-Seok; Suh, Soong-Hyuck

2009-01-01

The depletion interactions acting between two hard colloids immersed in a bath of polymers, in which the interaction potentials include the soft repulsion/attraction, are extensively studied by using the molecular dynamics simulations. The collision frequencies and collision angle distributions for both incidental and reflection conditions are computed to study the dynamic properties of the colloidal mixtures. The depletion effect induced by the polymer-polymer and colloid-polymer interactions are investigated as well as the size ratio of the colloid and polymer. The simulated results show that the strong depletion interaction between two hard colloids appears for the highly asymmetric hard-disc mixtures. The attractive depletion force at contact becomes deeper and the repulsive barrier becomes wider as the asymmetry in size ratio increases. The strong polymer-polymer attraction leads to the purely attractive depletion interaction between two hard colloids, whereas the purely repulsive depletion interaction is induced by the strong colloid-polymer attraction.

Ring closure in actin polymers

Energy Technology Data Exchange (ETDEWEB)

Sinha, Supurna, E-mail: supurna@rri.res.in [Raman Research Institute, Bangalore 560080 (India); Chattopadhyay, Sebanti [Doon University, Dehradun 248001 (India)

2017-03-18

We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers. - Highlights: • Ring closure of biopolymers. • Worm like chain model. • Predictions for experiments.

Surface-Modified Quantum Dots Enhanced Luminescence Polymer Nanocomposites Light Emitting Diode

National Research Council Canada - National Science Library

Wei, Kung-Hwa

2006-01-01

.... Both the photoluminescence and electroluminescence efficiencies of the polymer nanocomposites are dramatically enhanced--sometimes by more than double--relative to the values of the pure polymer...

Thiacrown polymers for removal of mercury from waste streams

Science.gov (United States)

Baumann, Theodore F.; Reynolds, John G.; Fox, Glenn A.

2004-02-24

Thiacrown polymers immobilized to a polystyrene-divinylbenzene matrix react with Hg.sup.2+ under a variety of conditions to efficiently and selectively remove Hg.sup.2+ ions from acidic aqueous solutions, even in the presence of a variety of other metal ions. The mercury can be recovered and the polymer regenerated. This mercury removal method has utility in the treatment of industrial wastewater, where a selective and cost-effective removal process is required.

Flexible Photonics: Polymer LEDs Made from Monochromatic Red Emitting Lanthanide/Polymer Blends. Phase 1

National Research Council Canada - National Science Library

O'Regan, Marie

1999-01-01

.... Spectrally pure, red emitting flexible LEDs have been fabricated. Close to a four-fold increase in device efficiency is obtained when a suitable lanthanide complex is blended with the semi-conducting host polymer...

Changes in the electrical properties of pure and doped polymers under the influence of small doses of X-rays

Science.gov (United States)

Mahmoud, S. A.; Madi, N. K.; Kassem, M. E.; El-Khatib, A.

A study has been made of the temperature dependence of the d.c. conductivity of pure and borated low density polyethylene LDPE (4% and 8% borax). The above calculations were carried out before and after X-ray irradiation. The irradiation dose was varied from 0 to 1000 rad. The d.c. electrical conductivity of Polyvinyl chloride (PVC) and perspex was measured as a function of temperature ranging from 20°C to 100°C. These samples were irradiated with X-rays of dose 200 rad. The variation of the d.c. conductivity of the treated samples versus temperature was investigated. The results reveal that the d.c. conductivity of LDPE is highly affected by radiation and/or dopant. In addition, the sensitivity of the explored polymers to X-ray irradiation is strongly dependent on its chemical nature.

Pressure-dependent pure- and mixed-gas permeation properties of Nafion®

KAUST Repository

Mukaddam, Mohsin Ahmed; Litwiller, Eric; Pinnau, Ingo

2016-01-01

observed phenomena: compression and plasticization. In pure-gas experiments, at increasing feed pressure, compression of the polymer matrix reduced the permeability of low-sorbing penetrants H2, N2, O2, and CH4. In contrast, permeabilities of more soluble

Enzymatic degradation of polymer covered SOPC-liposomes in relation to drug delivery

DEFF Research Database (Denmark)

Davidsen, Jesper; Vermehren, C.; Frøkjær, S.

2001-01-01

Polyethylenoxide (PEG) covered liposomes are used as lipid-based drug-delivery systems. In comparison to conventional liposomes the polymer-covered liposomes display a long circulation half-life in the blood stream. We investigate the influence of polyethyleneoxide-distearoylphosphatidylethanolam......Polyethylenoxide (PEG) covered liposomes are used as lipid-based drug-delivery systems. In comparison to conventional liposomes the polymer-covered liposomes display a long circulation half-life in the blood stream. We investigate the influence of polyethyleneoxide...

Pure apraxia of speech due to infarct in premotor cortex.

Science.gov (United States)

Patira, Riddhi; Ciniglia, Lauren; Calvert, Timothy; Altschuler, Eric L

Apraxia of speech (AOS) is now recognized as an articulation disorder distinct from dysarthria and aphasia. Various lesions have been associated with AOS in studies that are limited in precise localization due to variability in size and type of pathology. We present a case of pure AOS in setting of an acute stroke to localize more precisely than ever before the brain area responsible for AOS, dorsal premotor cortex (dPMC). The dPMC is in unique position to plan and coordinate speech production by virtue of its connection with nearby motor cortex harboring corticobulbar tract, supplementary motor area, inferior frontal operculum, and temporo-parietal area via the dorsal stream of dual-stream model of speech processing. The role of dPMC is further supported as part of dorsal stream in the dual-stream model of speech processing as well as controller in the hierarchical state feedback control model. Copyright © 2017 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Delocalization in polymer models

CERN Document Server

Jitomirskaya, S Yu; Stolz, G

2003-01-01

A polymer model is a one-dimensional Schroedinger operator composed of two finite building blocks. If the two associated transfer matrices commute, the corresponding energy is called critical. Such critical energies appear in physical models, an example being the widely studied random dimer model. Although the random models are known to have pure-point spectrum with exponentially localized eigenstates for almost every configuration of the polymers, the spreading of an initially localized wave packet is here proven to be at least diffusive for every configuration.

Organic thin film transistors and polymer light-emitting diodes patterned by polymer inking and stamping

International Nuclear Information System (INIS)

Li Dawen; Guo, L Jay

2008-01-01

To fully realize the advantages of organic flexible electronics, patterning is very important. In this paper we show that a purely additive patterning technique, termed polymer inking and stamping, can be used to pattern conductive polymer PEDOT and fabricate sub-micron channel length organic thin film transistors. In addition, we applied the technique to transfer a stack of metal/conjugated polymer in one step and fabricated working polymer light-emitting devices. Based on the polymer inking and stamping technique, a roll-to-roll printing for high throughput fabrication has been demonstrated. We investigated and explained the mechanism of this process based on the interfacial energy consideration and by using the finite element analysis. This technique can be further extended to transfer more complex stacked layer structures, which may benefit the research on patterning on flexible substrates

Future of radiation processing of polymers

International Nuclear Information System (INIS)

Chapiro, A.; Tabata, Y.; Stannett, V.; Dole, M.; Dobo, J.; Charlesby, A.

1990-01-01

The present development of radiation processing in the polymer field including well established technologies, with large scale productions and substantial markets, such as: crosslinking; curing of monomer-polymer formulations; sterilization of plastic supplies; are discussed. The manufacture of sophisticated devices with low volume production but large added value: electronic devices; resistors and several promising applications for which only small commercial productions are on stream today: chain degradation; polymerization; graft copolymerization, are reviewed. (author)

The upcycling of post-industrial PP/PET waste streams through in-situ microfibrillar preparation

International Nuclear Information System (INIS)

Delva, Laurens; Ragaert, Kim; Cardon, Ludwig

2015-01-01

Post-industrial plastic waste streams can be re-used as secondary material streams for polymer processing by extrusion or injection moulding. One of the major commercially available waste stream contains polypropylene (PP) contaminated with polyesters (mostly polyethylene tereftalate - PET). An important practical hurdle for the direct implementation of this waste stream is the immiscibility of PP and PET in the melt, which leads to segregation within the polymer structure and adversely affects the reproducibility and mechanical properties of the manufactured parts. It has been indicated in literature that the creation of PET microfibrils in the PP matrix could undo these drawbacks and upcycle the PP/PET combination. Within the current research, a commercially available virgin PP/PET was evaluated for the microfibrillar preparation. The mechanical (tensile and impact) properties, thermal properties and morphology of the composites were characterized at different stages of the microfibrillar preparation

The upcycling of post-industrial PP/PET waste streams through in-situ microfibrillar preparation

Energy Technology Data Exchange (ETDEWEB)

Delva, Laurens, E-mail: Laurens.Delva@ugent.be; Ragaert, Kim, E-mail: Kim.Ragaert@ugent.be; Cardon, Ludwig, E-mail: Ludwig.Cardon@ugent.be [Centre for Polymer and Materials Technologies (CPMT), Department of Materials Science and Engineering, Ghent University, Technologiepark 915, 9052 Zwijnaarde (Belgium)

2015-12-17

Post-industrial plastic waste streams can be re-used as secondary material streams for polymer processing by extrusion or injection moulding. One of the major commercially available waste stream contains polypropylene (PP) contaminated with polyesters (mostly polyethylene tereftalate - PET). An important practical hurdle for the direct implementation of this waste stream is the immiscibility of PP and PET in the melt, which leads to segregation within the polymer structure and adversely affects the reproducibility and mechanical properties of the manufactured parts. It has been indicated in literature that the creation of PET microfibrils in the PP matrix could undo these drawbacks and upcycle the PP/PET combination. Within the current research, a commercially available virgin PP/PET was evaluated for the microfibrillar preparation. The mechanical (tensile and impact) properties, thermal properties and morphology of the composites were characterized at different stages of the microfibrillar preparation.

The upcycling of post-industrial PP/PET waste streams through in-situ microfibrillar preparation

Science.gov (United States)

Delva, Laurens; Ragaert, Kim; Cardon, Ludwig

2015-12-01

Post-industrial plastic waste streams can be re-used as secondary material streams for polymer processing by extrusion or injection moulding. One of the major commercially available waste stream contains polypropylene (PP) contaminated with polyesters (mostly polyethylene tereftalate - PET). An important practical hurdle for the direct implementation of this waste stream is the immiscibility of PP and PET in the melt, which leads to segregation within the polymer structure and adversely affects the reproducibility and mechanical properties of the manufactured parts. It has been indicated in literature that the creation of PET microfibrils in the PP matrix could undo these drawbacks and upcycle the PP/PET combination. Within the current research, a commercially available virgin PP/PET was evaluated for the microfibrillar preparation. The mechanical (tensile and impact) properties, thermal properties and morphology of the composites were characterized at different stages of the microfibrillar preparation.

Simulation of nuclear magnetic resonance spectra of liquid crystals, polymers liquid crystals and conventional polymers

International Nuclear Information System (INIS)

Gerard, H.

1993-01-01

The aim of this study is the simulation and the exploitation of NMR spectra of nematic liquid crystals and of polymers. The NMR forms of lines are analysed owing to two complementary models. The first (single conformation model) describes the purely molecular contribution (geometry and internal movements in the molecule), the second the contribution of collective movements (visco elastic modes). Recallings on the NMR method and the orientational order notion within the nematic phase, are given in the first part, where these two models are also described. In a second part these models are applied to data relative to nematic molecules of weak molecular mass and to nematic polymers. This application allows to obtain informations on the structure and the internal movements of the molecule, the orientational order prevailing within the phase and the visco-elastic properties of the studied material. At last it is demonstrated that extension of these models to NMR data of polymers which don't present nematic phase in pure phase allows to obtain similar informations if we consider that their amorphous phase presents locally a nematic order. 136 refs., 46 figs., 4 tabs

Structure and transport properties of polymer grafted nanoparticles

KAUST Repository

Goyal, Sushmit; Escobedo, Fernando A.

2011-01-01

We perform molecular dynamics simulations on a bead-spring model of pure polymer grafted nanoparticles (PGNs) and of a blend of PGNs with a polymer melt to investigate the correlation between PGN design parameters (such as particle core concentration, polymer grafting density, and polymer length) and properties, such as microstructure, particle mobility, and viscous response. Constant strain-rate simulations were carried out to calculate viscosities and a constant-stress ensemble was used to calculate yield stresses. The PGN systems are found to have less structural order, lower viscosity, and faster diffusivity with increasing length of the grafted chains for a given core concentration or grafting density. Decreasing grafting density causes depletion effects associated with the chains leading to close contacts between some particle cores. All systems were found to shear thin, with the pure PGN systems shear thinning more than the blend; also, the pure systems exhibited a clear yielding behavior that was absent in the blend. Regarding the mechanism of shear thinning at the high shear rates examined, it was found that the shear-induced decrease of Brownian stresses and increase in chain alignment, both correlate with the reduction of viscosity in the system with the latter being more dominant. A coupling between Brownian stresses and chain alignment was also observed wherein the non-equilibrium particle distribution itself promotes chain alignment in the direction of shear. © 2011 American Institute of Physics.

Wettability and ζ potentials of a series of methacrylate polymers and copolymers

NARCIS (Netherlands)

Hogt, A.H.; Gregonis, D.E.; Andrade, J.D.; Kim, S.W.; Dankert, J.; Feijen, Jan

1985-01-01

Polymers and copolymers of different methacrylates were synthesized and coated on glass slides. The surfaces of the polymer films were characterized by their water contact angles and potentials using the Wilhelmy plate technique and streaming potential measurements, respectively. From contact-angle

Application of hybrid organic/inorganic polymers as coatings on metallic substrates

Science.gov (United States)

Augustinho, T. R.; Motz, G.; Ihlow, S.; Machado, R. A. F.

2016-09-01

Acrylic polymers, particularly poly (methyl methacrylate) (PMMA), have certain specific properties, such as good film formation, transparency, and good mechanical properties, which have been widely used in paints, coatings and adhesives. However, the limited chemical and physical stability of these pure polymers limits their applications when exposed to hostile conditions, as in ship hulls, for example. A suitable way to enhance PMMA properties is the addition of silicon polymers with very good protective characteristics. In this study, a PMMA and HTT 1800 (commercial silazane) copolymer were applied on metallic substrate and compared to pure PMMA and HTT 1800. All the materials were applied as coatings. They were applied on stainless steel via dip-coating to investigate the coating properties. Thermal cycling was employed to analyze coating durability at high temperatures (50 °C to 600 °C). Optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the coated surfaces, and the adhesion of pure PMMA, pure HTT 1800 and PMMA/HTT 1800 coatings on metallic substrate was investigated by Cross-Cut-Test (ASTM D 3359). The sessile drop method was used to determine the contact angle. PMMA coatings presented complete degradation from 250 °C, while hybrid coatings of PMMA and HTT 1800 have good protection until 400 °C. The adherence of the coating on metallic substrate showed improvement in all synthesized materials when compared to pure PMMA, obtaining the best adherence possible. The contact angle test showed that the hydrophobicity of the hybrid coatings is higher than that of the pure coatings.

Synthesis, thermal properties and applications of polymer-clay nanocomposites

International Nuclear Information System (INIS)

Meneghetti, Paulo; Qutubuddin, Syed

2006-01-01

Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T g ) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T g 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films

Synthesis, thermal properties and applications of polymer-clay nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Meneghetti, Paulo [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States); Qutubuddin, Syed [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States)]. E-mail: sxq@case.edu

2006-03-15

Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T {sub g}) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T {sub g} 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films.

Stochastic resonance during a polymer translocation process

International Nuclear Information System (INIS)

Mondal, Debasish; Muthukumar, M.

2016-01-01

We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

Crystal and molecular simulation of high-performance polymers.

Science.gov (United States)

Colquhoun, H M; Williams, D J

2000-03-01

Single-crystal X-ray analyses of oligomeric models for high-performance aromatic polymers, interfaced to computer-based molecular modeling and diffraction simulation, have enabled the determination of a range of previously unknown polymer crystal structures from X-ray powder data. Materials which have been successfully analyzed using this approach include aromatic polyesters, polyetherketones, polythioetherketones, polyphenylenes, and polycarboranes. Pure macrocyclic homologues of noncrystalline polyethersulfones afford high-quality single crystals-even at very large ring sizes-and have provided the first examples of a "protein crystallographic" approach to the structures of conventionally amorphous synthetic polymers.

Polymer Mixtures and Films: Free Volume as a Driving Force for Miscibility and Glassiness

Science.gov (United States)

DeFelice, Jeffrey

The microscopic characteristics of polymer molecules are connected with many macro- scopic and mechanical properties of their liquid (pure or mixed) and solid states. How these properties are affected by the different molecular attributes of polymers is of particular interest for practical applications of polymer materials. In Part I of this thesis, the thermodynamics of polymer/supercritical CO2 mixtures and blends of linear and branched polymers are modeled using a lattice based equation of state approach. Analyses of trends in the pure component physical properties lead to insight regarding how changes in molecular architecture and/or isotopic labeling affect the relative compatibilities of the mixtures. This approach is also applied to the mixed state to predict the enthalpic and entropic changes of mixing, from which, information is provided about the role of pure component properties in controlling the underlying thermodynamics of the mixtures. In Part II, the focus of this thesis turns to how interfacial effects can shift a number of physical properties in glass forming fluids relative to those of the pure bulk material. One of the most notable deviations from bulk behavior that has been reported for these systems is a change in the glass transition temperature (Tg). In this work, interfacial effects on Tg are probed in film and polymer/additive systems using a simple kinetic lattice model that simulates free volume and mobility in glass forming fluids. For films, the thickness-dependent behavior of Tg is characterized for different types of interfaces, including films that are substrate supported, free- standing, and 'stacked'. Connections are drawn between the size of the region of enhanced mobility near a free surface and the distribution of local Tg values across a film. For polymer/additive systems, where the "interface" is dispersed throughout the material, trends in additive induced Tg changes are analyzed with respect to additive concentration and

Wettability and ζ potentials of a series of methacrylate polymers and copolymers

OpenAIRE

Hogt, A.H.; Gregonis, D.E.; Andrade, J.D.; Kim, S.W.; Dankert, J.; Feijen, Jan

1985-01-01

Polymers and copolymers of different methacrylates were synthesized and coated on glass slides. The surfaces of the polymer films were characterized by their water contact angles and potentials using the Wilhelmy plate technique and streaming potential measurements, respectively. From contact-angle measurements information was also obtained about mobility of surface polymer chains. Receding contact angles of methyl methacrylate (MMA) copolymers containing hydrophilic or charged units were dec...

Trapping, focusing, and sorting of microparticles through bubble streaming

Science.gov (United States)

Wang, Cheng; Jalikop, Shreyas; Hilgenfeldt, Sascha

2010-11-01

Ultrasound-driven oscillating microbubbles can set up vigorous steady streaming flows around the bubbles. In contrast to previous work, we make use of the interaction between the bubble streaming and the streaming induced around mobile particles close to the bubble. Our experiment superimposes a unidirectional Poiseuille flow containing a well-mixed suspension of neutrally buoyant particles with the bubble streaming. The particle-size dependence of the particle-bubble interaction selects which particles are transported and which particles are trapped near the bubbles. The sizes selected for can be far smaller than any scale imposed by the device geometry, and the selection mechanism is purely passive. Changing the amplitude and frequency of ultrasound driving, we can further control focusing and sorting of the trapped particles, leading to the emergence of sharply defined monodisperse particle streams within a much wider channel. Optimizing parameters for focusing and sorting are presented. The technique is applicable in important fields like cell sorting and drug delivery.

Laser streaming: Turning a laser beam into a flow of liquid.

Science.gov (United States)

Wang, Yanan; Zhang, Qiuhui; Zhu, Zhuan; Lin, Feng; Deng, Jiangdong; Ku, Geng; Dong, Suchuan; Song, Shuo; Alam, Md Kamrul; Liu, Dong; Wang, Zhiming; Bao, Jiming

2017-09-01

Transforming a laser beam into a mass flow has been a challenge both scientifically and technologically. We report the discovery of a new optofluidic principle and demonstrate the generation of a steady-state water flow by a pulsed laser beam through a glass window. To generate a flow or stream in the same path as the refracted laser beam in pure water from an arbitrary spot on the window, we first fill a glass cuvette with an aqueous solution of Au nanoparticles. A flow will emerge from the focused laser spot on the window after the laser is turned on for a few to tens of minutes; the flow remains after the colloidal solution is completely replaced by pure water. Microscopically, this transformation is made possible by an underlying plasmonic nanoparticle-decorated cavity, which is self-fabricated on the glass by nanoparticle-assisted laser etching and exhibits size and shape uniquely tailored to the incident beam profile. Hydrophone signals indicate that the flow is driven via acoustic streaming by a long-lasting ultrasound wave that is resonantly generated by the laser and the cavity through the photoacoustic effect. The principle of this light-driven flow via ultrasound, that is, photoacoustic streaming by coupling photoacoustics to acoustic streaming, is general and can be applied to any liquid, opening up new research and applications in optofluidics as well as traditional photoacoustics and acoustic streaming.

Energy storage in ferroelectric polymer nanocomposites filled with core-shell structured polymer@BaTiO3 nanoparticles: understanding the role of polymer shells in the interfacial regions.

Science.gov (United States)

Zhu, Ming; Huang, Xingyi; Yang, Ke; Zhai, Xing; Zhang, Jun; He, Jinliang; Jiang, Pingkai

2014-11-26

The interfacial region plays a critical role in determining the electrical properties and energy storage density of dielectric polymer nanocomposites. However, we still know a little about the effects of electrical properties of the interfacial regions on the electrical properties and energy storage of dielectric polymer nanocomposites. In this work, three types of core-shell structured polymer@BaTiO3 nanoparticles with polymer shells having different electrical properties were used as fillers to prepare ferroelectric polymer nanocomposites. All the polymer@BaTiO3 nanoparticles were prepared by surface-initiated reversible-addition-fragmentation chain transfer (RAFT) polymerization, and the polymer shells were controlled to have the same thickness. The morphology, crystal structure, frequency-dependent dielectric properties, breakdown strength, leakage currents, energy storage capability, and energy storage efficiency of the polymer nanocomposites were investigated. On the other hand, the pure polymers having the same molecular structure as the shells of polymer@BaTiO3 nanoparticles were also prepared by RAFT polymerization, and their electrical properties were provided. Our results show that, to achieve nanocomposites with high discharged energy density, the core-shell nanoparticle filler should simultaneously have high dielectric constant and low electrical conductivity. On the other hand, the breakdown strength of the polymer@BaTiO3-based nanocomposites is highly affected by the electrical properties of the polymer shells. It is believed that the electrical conductivity of the polymer shells should be as low as possible to achieve nanocomposites with high breakdown strength.

Depth-dependent positron annihilation in different polymers

Energy Technology Data Exchange (ETDEWEB)

Yang, J.; Zhang, P.; Cheng, G.D.; Li, D.X.; Wu, H.B.; Li, Z.X.; Cao, X.Z. [Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China); Jia, Q.J. [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China); Yu, R.S. [Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China); Wang, B.Y., E-mail: wangboy@ihep.ac.cn [Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China)

2013-09-01

Depth-dependent positron annihilation Doppler broadening measurements were conducted for polymers with different chemical compositions. Variations of the S parameter with respect to incident positron energy were observed. For pure hydrocarbons PP, HDPE and oxygen-containing polymer PC, S parameter rises with increasing positron implantation depth. While for PI and fluoropolymers like PTFE, ETFE and PVF, S parameter decreases with higher positron energy. For chlorine-containing polymer PVDC, S parameter remains nearly constant at all incident positron energies. It is suggested that these three variation trends are resulted from a competitive effect between the depth-dependent positronium formation and the influence of highly electronegative atoms on positron annihilation characteristics.

Measurement of Streaming Potential in Downhole Application: An Insight for Enhanced Oil Recovery Monitoring

Directory of Open Access Journals (Sweden)

Tengku Mohd Tengku Amran

2017-01-01

Full Text Available Downhole monitoring using streaming potential measurement has been developing in order to respond to actual reservoir condition. Most studies have emphasized on monitoring water flooding at various reservoir condition and improving the approaches of measurement. Enhanced Oil Recovery (EOR could significantly improve oil recovery and the efficiency of the process should be well-monitored. Alkaline-surfactant-polymer (ASP flooding is the most promising chemical EOR method due to its synergy of alkaline, surfactant and polymer, which could enhance the extraction of residual oil. However, limited studies have been focused on the application of streaming potential in EOR processes, particularly ASP. Thus, this paper aims to review the streaming potential measurement in downhole monitoring with an insight for EOR application and propose the potential measurement in monitoring ASP flooding. It is important for a preliminary study to investigate the synergy in ASP and the effects on oil recovery. The behaviour of streaming potential should be investigated when the environment of porous media changes with respect to ASP flooding. Numerical model can be generated from the experimental data to forecast the measured streaming potential signal during production associated with ASP flooding. Based on the streaming potential behaviour on foam assisted water alternate gas (FAWAG and water alternate gas (WAG processes, it is expected that the streaming potential could change significantly when ASP flooding alters the environment and surface properties of porous media. The findings could provide new prospect and knowledge in the relationship between streaming potential and ASP mechanisms, which could be a potential approach in monitoring the efficiency of the process.

Carbon fiber reinforced thermoplastic composites from acrylic polymer matrices: Interfacial adhesion and physical properties

Directory of Open Access Journals (Sweden)

H. Kishi

2017-04-01

Full Text Available Acrylic polymers have high potential as matrix polymers for carbon fiber reinforced thermoplastic polymers (CFRTP due to their superior mechanical properties and the fact that they can be fabricated at relatively low temperatures. We focused on improving the interfacial adhesion between carbon fibers (CFs and acrylic polymers using several functional monomers for co-polymerization with methyl methacrylate (MMA. The copolymerized acrylic matrices showed good adhesion to the CF surfaces. In particular, an acrylic copolymer with acrylamide (AAm showed high interfacial adhesive strength with CFs compared to pure PMMA, and a hydroxyethyl acrylamide (HEAA copolymer containing both amide and hydroxyl groups showed high flexural strength of the CFRTP. A 3 mol% HEAA-copolymerized CFRTP achieved a flexural strength almost twice that of pure PMMA matrix CFRTP, and equivalent to that of an epoxy matrix CFRP.

Poly(vinylpyridine-co-styrene) based in situ cross-linked gel polymer electrolyte for lithium-ion polymer batteries

International Nuclear Information System (INIS)

Oh, Sijin; Kim, Dong Wook; Lee, Changjin; Lee, Myong-Hoon; Kang, Yongku

2011-01-01

A gel polymer electrolyte (GPE) was successfully prepared by means of an in situ cross-linking reaction of poly(2-vinylpyridine-co-styrene) and oligo(ethylene oxide) with epoxide functional groups at 65 °C without using a polymerization initiator. A stable gel polymer electrolyte could be obtained by adding only 1% of a polymer gelator. The ionic conductivity of the GPE containing 99 wt% of liquid electrolyte was measured to be ca. 10 −2 S/cm at the ambient temperature. The ionic conductivity of the resulting GPE was comparable to that of a pure liquid electrolyte. The electrochemical stability window of the prepared gel polymer electrolytes was measured to be 5.2 V. The test cell carried a discharge capacity of 133.2 mAh/g at 0.1 C and showed good cycling performance with negligible capacity fading after the 200th cycle, maintaining 99.5% coulombic efficiency throughout 200 cycles. The resulting gel polymer electrolyte prepared by in situ thermal cross-linking without a polymerization initiator holds promise for application to on the high power lithium-ion polymer batteries.

White polymer light-emitting diodes based on star-shaped polymers with an orange dendritic phosphorescent core.

Science.gov (United States)

Zhu, Minrong; Li, Yanhu; Cao, Xiaosong; Jiang, Bei; Wu, Hongbin; Qin, Jingui; Cao, Yong; Yang, Chuluo

2014-12-01

A series of new star-shaped polymers with a triphenylamine-based iridium(III) dendritic complex as the orange-emitting core and poly(9,9-dihexylfluorene) (PFH) chains as the blue-emitting arms is developed towards white polymer light-emitting diodes (WPLEDs). By fine-tuning the content of the orange phosphor, partial energy transfer and charge trapping from the blue backbone to the orange core is realized to achieve white light emission. Single-layer WPLEDs with the configuration of ITO (indium-tin oxide)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/polymer/CsF/Al exhibit a maximum current efficiency of 1.69 cd A(-1) and CIE coordinates of (0.35, 0.33), which is very close to the pure white-light point of (0.33, 0.33). To the best of our knowledge, this is the first report on star-shaped white-emitting single polymers that simultaneously consist of fluorescent and phosphorescent species. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

KAUST Repository

Heumueller, Thomas

2014-08-01

In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which polymer is used. We show that the light-induced traps are in the bulk of the active layer and we find a direct correlation between their presence and the open-circuit voltage loss in devices made with amorphous polymers. Solar cells made with crystalline polymers do not show characteristic open circuit voltage losses, even though light-induced traps are also present in these devices. This indicates that crystalline materials are more resistant against the influence of traps on device performance. Recent work on crystalline materials has shown there is an energetic driving force for charge carriers to leave amorphous, mixed regions of bulk heterojunctions, and charges are dominantly transported in pure, ordered phases. This energetic landscape allows efficient charge generation as well as extraction and also may benefit the stability against light-induced traps. This journal is © the Partner Organisations 2014.

Java parallel secure stream for grid computing

International Nuclear Information System (INIS)

Chen, J.; Akers, W.; Chen, Y.; Watson, W.

2001-01-01

The emergence of high speed wide area networks makes grid computing a reality. However grid applications that need reliable data transfer still have difficulties to achieve optimal TCP performance due to network tuning of TCP window size to improve the bandwidth and to reduce latency on a high speed wide area network. The authors present a pure Java package called JPARSS (Java Parallel Secure Stream) that divides data into partitions that are sent over several parallel Java streams simultaneously and allows Java or Web applications to achieve optimal TCP performance in a gird environment without the necessity of tuning the TCP window size. Several experimental results are provided to show that using parallel stream is more effective than tuning TCP window size. In addition X.509 certificate based single sign-on mechanism and SSL based connection establishment are integrated into this package. Finally a few applications using this package will be discussed

Polymer Stabilization of Liquid-Crystal Blue Phase II toward Photonic Crystals.

Science.gov (United States)

Jo, Seong-Yong; Jeon, Sung-Wook; Kim, Byeong-Cheon; Bae, Jae-Hyun; Araoka, Fumito; Choi, Suk-Won

2017-03-15

The temperature ranges where a pure simple-cubic blue phase (BPII) emerges are quite narrow compared to the body-centered-cubic BP (BPI) such that the polymer stabilization of BPII is much more difficult. Hence, a polymer-stabilized BPII possessing a wide temperature range has been scarcely reported. Here, we fabricate a polymer-stabilized BPII over a temperature range of 50 °C including room temperature. The fabricated polymer-stabilized BPII is confirmed via polarized optical microscopy, Bragg reflection, and Kossel diagram observations. Furthermore, we demonstrate reflective BP liquid-crystal devices utilizing the reflectance-voltage performance as a potential application of the polymer-stabilized BPII. Our work demonstrates the possibility of practical application of the polymer-stabilized BPII to photonic crystals.

Miscibility of polymer blends with engineering models

DEFF Research Database (Denmark)

Vassilis, Harismiadis; van Bergen, A. R. D.; Goncalves, Ana Saraiva

1996-01-01

compared. The van der Waals equation of state was recently shown to accurately correlate and predict vapor-liquid and liquid-liquid equilibria for binary polymer/solvent solutions. In this work, it is demonstrated that it correlates the upper critical solution behavior of polymer blends with excellent...... accuracy using the usual mixing and combining rules and a single temperature- and composition-independent binary interaction parameter. This interaction parameter can be predicted via a generalized expression that uses only the pure component equation-of-state parameters. Using this generalized expression...

m-Carboranylphosphinate as Versatile Building Blocks To Design all Inorganic Coordination Polymers.

Science.gov (United States)

Oleshkevich, Elena; Viñas, Clara; Romero, Isabel; Choquesillo-Lazarte, Duane; Haukka, Matti; Teixidor, Francesc

2017-05-15

The first examples of coordination polymers of manganese(II) and a nickel(II) complex with a purely inorganic carboranylphosphinate ligand are reported, together with its exhaustive characterization. X-ray analysis revealed 1D polymeric chains with carboranylphosphinate ligands bridging two manganese(II) centers. The reactivity of polymer 1 with water and Lewis bases has also been studied.

Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

DEFF Research Database (Denmark)

Qingfeng, Li; Bergqvist, R. S.; Hjuler, H. A.

1999-01-01

Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and PBI polymer electrolytes in a temperature range from 80 to 190°C. Compared with pure H3PO4, using the H3PO4 doped Nafion and PBI polymer electrolytes can significantly improve the oxygen...

Effect of Hydrogen Bonding on Linear and Nonlinear Rheology of Entangled Polymer Melts

DEFF Research Database (Denmark)

Shabbir, Aamir; Goldansaz, Hadi; Hassager, Ole

2015-01-01

for a model system of pure poly(n-butyl acrylate), PnBA, homopolymer and four PnBA− poly(acrylic acid), PnBA−PAA, copolymers with different number of AA side groups. The copolymers are synthesized via hydrolysis of the pure PnBA homopolymer. Therefore, all polymers studied have the same backbone length...

Physical, mechanical, and biodegradable properties of meranti wood polymer composites

International Nuclear Information System (INIS)

Enamul Hoque, M.; Aminudin, M.A.M.; Jawaid, M.; Islam, M.S.; Saba, N.; Paridah, M.T.

2014-01-01

Highlights: • In-situ polymerization and solution casting method used to manufacture WPC. • In-situ WPC exhibited better properties compared to pure wood, 5% WPC and 20% WPC. • Lowest water absorption and least biodegradability shown by In-situ wood. - Abstract: In-situ polymerization and solution casting techniques are two effective methods to manufacture wood polymer composites (WPCs). In this study, wood polymer composites (WPCs) were manufactured from meranti sapwood by solution casting and in-situ polymerization process using methyl methacrylate (MMA) and epoxy matrix respectively. Physical, mechanical, and morphological characterizations of fabricated WPCs were then carried out to analyse their properties. Morphological properties of composites samples were analyzed through scanning electron microscopy (SEM). The result reveals that in-situ wood composite exhibited better properties compared to pure wood, 5% WPC and 20% WPC. Moreover, in-situ WPC had lowest water absorption and least biodegraded. Conversely, pure wood shown moderate mechanical strength, high biodegradation and water absorption rate. In term of biodegradation, earth-medium brought more severe effect than water in deteriorating the properties of the specimens

Method for high temperature mercury capture from gas streams

Science.gov (United States)

Granite, Evan J [Wexford, PA; Pennline, Henry W [Bethel Park, PA

2006-04-25

A process to facilitate mercury extraction from high temperature flue/fuel gas via the use of metal sorbents which capture mercury at ambient and high temperatures. The spent sorbents can be regenerated after exposure to mercury. The metal sorbents can be used as pure metals (or combinations of metals) or dispersed on an inert support to increase surface area per gram of metal sorbent. Iridium and ruthenium are effective for mercury removal from flue and smelter gases. Palladium and platinum are effective for mercury removal from fuel gas (syngas). An iridium-platinum alloy is suitable for metal capture in many industrial effluent gas streams including highly corrosive gas streams.

Diagnostics of high-speed streams and coronal holes using geomagnetic pulsations

International Nuclear Information System (INIS)

Bol'shakova, O.V.; Troitskaya, V.A.

1980-01-01

In order to study the relations of high-speed solar wind streams and coronal holes analyzed are the parameters of geomagnetic pulsations of the Rs3 type and of high-speed streams at the decrease branch and in the minimum of solar activity. On the basis of the analysis of exciting pulsation regime determined are the differences in characteristics of high-speed stream properties. Presented are the graphical distributions of a number of occurrances of high-speed streams, coronal holes and pure regimes of Rs3R pulsations in several sections of 1973 in the Sun rotations of N1903-1919 and of the change of solar wind velocity while passing through the high-speed streams. It is found that Rs3R occurrance can serve an indicator of the high-speed flux connection with the large equatorial coronal hole. On the basis of the analysis of exciting pulsation properties determined are the differences in the stream characteristics. However the preliminary estimates permit to adopt neither the first nor the second of the existing hypotheses on the sourse of formation of high-speed streams

Mixed-Penetrant Sorption in Ultrathin Films of Polymer of Intrinsic Microporosity PIM-1.

Science.gov (United States)

Ogieglo, Wojciech; Furchner, Andreas; Ghanem, Bader; Ma, Xiaohua; Pinnau, Ingo; Wessling, Matthias

2017-11-02

Mixed-penetrant sorption into ultrathin films of a superglassy polymer of intrinsic microporosity (PIM-1) was studied for the first time by using interference-enhanced in situ spectroscopic ellipsometry. PIM-1 swelling and the concurrent changes in its refractive index were determined in ultrathin (12-14 nm) films exposed to pure and mixed penetrants. The penetrants included water, n-hexane, and ethanol and were chosen on the basis of their significantly different penetrant-penetrant and penetrant-polymer affinities. This allowed studying microporous polymer responses at diverse ternary compositions and revealed effects such as competition for the sorption sites (for water/n-hexane or ethanol/n-hexane) or enhancement in sorption of typically weakly sorbing water in the presence of more highly sorbing ethanol. The results reveal details of the mutual sorption effects which often complicate comprehension of glassy polymers' behavior in applications such as high-performance membranes, adsorbents, or catalysts. Mixed-penetrant effects are typically very challenging to study directly, and their understanding is necessary owing to a broadly recognized inadequacy of simple extrapolations from measurements in a pure component environment.

Low porosity portland cement pastes based on furan polymers

International Nuclear Information System (INIS)

Darweesh, H.H.M.

2005-01-01

The effect of three different types of Furan polymers on the porosity, mechanical properties, mechanism of hydration and microstructure of Ordinary Portland cement (OPC) pastes was investigated. The results showed that mixing the OPC with Furan polymers, the standard water of consistency of the different cement pastes decreases and therefore the setting times (initial and final) are shortened. The total porosity of the hardened cement pastes decreased, while the mechanical properties improved and enhanced at all curing ages of hydration compared with those of the pure OPC pastes. The hydration process with Furan polymers proceeded according to the following decreasing order: F.ac. > F.ph. > F.alc. > OPC

Carbon Nanotube Dispersion in Solvents and Polymer Solutions: Mechanisms, Assembly, and Preferences.

Science.gov (United States)

Pramanik, Chandrani; Gissinger, Jacob R; Kumar, Satish; Heinz, Hendrik

2017-12-26

Debundling and dispersion of carbon nanotubes (CNTs) in polymer solutions play a major role in the preparation of carbon nanofibers due to early effects on interfacial ordering and mechanical properties. A roadblock toward ultrastrong fibers is the difficulty to achieve homogeneous dispersions of CNTs in polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) precursor solutions in solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF). In this contribution, molecular dynamics simulations with accurate interatomic potentials for graphitic materials that include virtual π electrons are reported to analyze the interaction of pristine single wall CNTs with the solvents and polymer solutions at 25 °C. The results explain the barriers toward dispersion of SWCNTs and quantify CNT-solvent, polymer-solvent, as well as CNT-polymer interactions in atomic detail. Debundling of CNTs is overall endothermic and unfavorable with dispersion energies of +20 to +30 mJ/m 2 in the pure solvents, + 20 to +40 mJ/m 2 in PAN solutions, and +20 to +60 mJ/m 2 in PMMA solutions. Differences arise due to molecular geometry, polar, van der Waals, and CH-π interactions. Among the pure solvents, DMF restricts CNT dispersion less due to the planar geometry and stronger van der Waals interactions. PAN and PMMA interact favorably with the pure solvents with dissolution energies of -0.7 to -1.1 kcal per mole monomer and -1.5 to -2.2 kcal per mole monomer, respectively. Adsorption of PMMA onto CNTs is stronger than that of PAN in all solvents as the molecular geometry enables more van der Waals contacts between alkyl groups and the CNT surface. Polar side groups in both polymers prefer interactions with the polar solvents. Higher polymer concentrations in solution lead to polymer aggregation via alkyl groups and reduce adsorption onto CNTs. PAN and PMMA solutions in DMSO and dilute solutions in DMF support CNT dispersion more than other

Fermentative utilization of coffee mucilage using Bacillus coagulans and investigation of down-stream processing of fermentation broth for optically pure l(+)-lactic acid production.

Science.gov (United States)

Neu, Anna-Katrin; Pleissner, Daniel; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim

2016-07-01

In this study, mucilage, a residue from coffee production, was investigated as substrate in fermentative l(+)-lactic acid production. Mucilage was provided as liquid suspension consisting glucose, galactose, fructose, xylose and sucrose as free sugars (up to 60gL(-1)), and used directly as medium in Bacillus coagulans batch fermentations carried out at 2 and 50L scales. Using mucilage and 5gL(-1) yeast extract as additional nitrogen source, more than 40gL(-1) lactic acid was obtained. Productivity and yield were 4-5gL(-1)h(-1) and 0.70-0.77g lactic acid per g of free sugars, respectively, irrespective the scale. Similar yield was found when no yeast extract was supplied, the productivity, however, was 1.5gL(-1)h(-1). Down-stream processing of culture broth, including filtration, electrodialysis, ion exchange chromatography and distillation, resulted in a pure lactic acid formulation containing 930gL(-1)l(+)-lactic acid. Optical purity was 99.8%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water-soluble chelating polymers for removal of actinides from wastewater

International Nuclear Information System (INIS)

Jarvinen, G.D.

1997-01-01

Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent

Water-soluble chelating polymers for removal of actinides from wastewater

Energy Technology Data Exchange (ETDEWEB)

Jarvinen, G.D. [Los Alamos National Lab., NM (United States)

1997-10-01

Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent.

Sortase-Mediated Ligation of Purely Artificial Building Blocks

Directory of Open Access Journals (Sweden)

Xiaolin Dai

2018-02-01

Full Text Available Sortase A (SrtA from Staphylococcus aureus has been often used for ligating a protein with other natural or synthetic compounds in recent years. Here we show that SrtA-mediated ligation (SML is universally applicable for the linkage of two purely artificial building blocks. Silica nanoparticles (NPs, poly(ethylene glycol and poly(N-isopropyl acrylamide are chosen as synthetic building blocks. As a proof of concept, NP–polymer, NP–NP, and polymer–polymer structures are formed by SrtA catalysis. Therefore, the building blocks are equipped with the recognition sequence needed for SrtA reaction—the conserved peptide LPETG—and a pentaglycine motif. The successful formation of the reaction products is shown by means of transmission electron microscopy (TEM, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS, and dynamic light scattering (DLS. The sortase catalyzed linkage of artificial building blocks sets the stage for the development of a new approach to link synthetic structures in cases where their synthesis by established chemical methods is complicated.

Photocatalytic activity of PANI loaded coordination polymer composite materials: Photoresponse region extension and quantum yields enhancement via the loading of PANI nanofibers on surface of coordination polymer

International Nuclear Information System (INIS)

Cui, Zhongping; Qi, Ji; Xu, Xinxin; Liu, Lu; Wang, Yi

2013-01-01

To enhance photocatalytic property of coordination polymer in visible light region, polyaniline (PANI) loaded coordination polymer photocatalyst was synthesized through in-situ chemical oxidation of aniline on the surface of coordination polymer. The photocatalytic activity of PANI loaded coordination polymer composite material for degradation of Rhodamine B (RhB) was investigated. Compared with pure coordination polymer photocatalyst, which can decompose RhB merely under UV light irradiation, PANI loaded coordination polymer photocatalyst displays more excellent photocatalytic activity in visible light region. Furthermore, PANI loaded coordination polymer photocatalyst exhibits outstanding stability during the degradation of RhB. - Graphical abstract: PANI loaded coordination polymer composite material, which displays excellent photocatalytic activity under visible light was firstly synthesized through in-situ chemical oxidation of aniline on surface of coordination polymer. Display Omitted - Highlights: • This PANI loaded coordination polymer composite material represents the first conductive polymer loaded coordination polymer composite material. • PANI/coordination polymer composite material displays more excellent photocatalytic activity for the degradation of MO in visible light region. • The “combination” of coordination polymer and PANI will enable us to design high-activity, high-stability and visible light driven photocatalyst in the future

Polymer systems testing: Final report

International Nuclear Information System (INIS)

1993-01-01

Los Alamos National Laboratory (LANL) is in the process of decontaminating lead shielding material. The procedure involves abrasive surface etching of the shielding to remove the outer layer of lead that contains the majority of the radioactive contaminants. This procedure generates a small volume of mixed waste in the form of a wet residue containing lead, abrasive grit (Al 2 O 3 ), uranium and water. IC Technologies, Inc. (ICT) has developed several processes for the treatment of mixed wastes involving stabilizing/encapsulating the waste in a polymer monolith. The objective of the test program was to verify the applicability of ICT's technology to this specific waste stream and provide LANL baseline data on the performance of polymer encapsulation techniques. Polymer microencapsulation of lead shielding/blasting grit (surrogate) mixed waste was evaluated. Two polymers, melamine formaldehyde and polyester xylene, were used to examine the effect of waste loading on Toxicity Characteristic Leaching Procedure (TCLP) extract Pb concentration. Six levels of waste loading were evaluated by eleven tests. Significant reduction in Pb solubility during TCLP was achieved. Additional optimization to the single-stage microencapsulation technique utilized will be necessary to mitigate the toxic (RCRA) characteristic of the waste

Methods of natural gas liquefaction and natural gas liquefaction plants utilizing multiple and varying gas streams

Science.gov (United States)

Wilding, Bruce M; Turner, Terry D

2014-12-02

A method of natural gas liquefaction may include cooling a gaseous NG process stream to form a liquid NG process stream. The method may further include directing the first tail gas stream out of a plant at a first pressure and directing a second tail gas stream out of the plant at a second pressure. An additional method of natural gas liquefaction may include separating CO.sub.2 from a liquid NG process stream and processing the CO.sub.2 to provide a CO.sub.2 product stream. Another method of natural gas liquefaction may include combining a marginal gaseous NG process stream with a secondary substantially pure NG stream to provide an improved gaseous NG process stream. Additionally, a NG liquefaction plant may include a first tail gas outlet, and at least a second tail gas outlet, the at least a second tail gas outlet separate from the first tail gas outlet.

Natural and artificial radionuclides in the Suez Canal bottom sediments and stream water

International Nuclear Information System (INIS)

El-Tahawy, M.S.; Farouk, M.A.; Ibrahiem, N.M.; El-Mongey, S.A.M.

1994-01-01

Concentration of natural and artificial radionuclides in Suez Canal bottom sediments and stream water have been measured using γ spectrometers based on a hyper-pure Ge detector. The activity concentrations of 238 U series, 232 Th series and 40 K did not exceed 16.0, 15.5 and 500.0 Bq kg -1 dry weight for sediments. The activity concentration of 238 U series and 40 K did not exceed 0.6 and 18.0 Bq l -1 for stream water. (author)

Natural and artificial radionuclides in the Suez Canal bottom sediments and stream water

Science.gov (United States)

El-Tahawy, M. S.; Farouk, M. A.; Ibrahiem, N. M.; El-Mongey, S. A. M.

1994-07-01

Concentration of natural and artificial radionuclides in Suez Canal bottom sediments and stream water have been measured using γ spectrometers based on a hyper-pure Ge detector. The activity concentrations of 238U series, 232Th series and 40K did not exceed 16.0, 15.5 and 500.0 Bq kg-1 dry weight for sediments. The activity concentration of 238U series and 40K did not exceed 0.6 and 18.0 Bq 1-1 for stream water.

Mechanistic modelling of drug release from polymer-coated and swelling and dissolving polymer matrix systems.

Science.gov (United States)

Kaunisto, Erik; Marucci, Mariagrazia; Borgquist, Per; Axelsson, Anders

2011-10-10

The time required for the design of a new delivery device can be sensibly reduced if the release mechanism is understood and an appropriate mathematical model is used to characterize the system. Once all the model parameters are obtained, in silico experiments can be performed, to provide estimates of the release from devices with different geometries and compositions. In this review coated and matrix systems are considered. For coated formulations, models describing the diffusional drug release, the osmotic pumping drug release, and the lag phase of pellets undergoing cracking in the coating due to the build-up of a hydrostatic pressure are reviewed. For matrix systems, models describing pure polymer dissolution, diffusion in the polymer and drug release from swelling and eroding polymer matrix formulations are reviewed. Importantly, the experiments used to characterize the processes occurring during the release and to validate the models are presented and discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Study of the influence of gold particles on the absorbed dose in soft tissue using polymer gel dosimetry

International Nuclear Information System (INIS)

Afonso, Luciana Caminha

2011-01-01

The presence of high-Z material adjacent to soft tissue, when submitted to irradiation, enhances locally the absorbed dose in these soft tissues. Such effect occurs due to the outscattering of photoelectrons from the high-Z material. Polymer gel dosimeters have been used to investigate this effect. Analytic calculations to estimate the dose enhancement and Monte Carlo simulations have been performed. Samples containing polymer gel (PG) with 0.005 gAu/gPG and pure polymer gel have been irradiated using an X-rays beam produced by 150 kV, filtered with 4 mm Al and 5 mm Cu, which resulted in an approximately 20% higher absorbed dose in the samples with gold in comparison to those with pure polymer gel. The analytic calculations and the Monte Carlo simulation resulted in a dose enhancement factor of approximately 30%. (author)

Polymer composite adsorbents using particles of molecularly imprinted polymers or aluminium oxide nanoparticles for treatment of arsenic contaminated waters.

Science.gov (United States)

Önnby, L; Pakade, V; Mattiasson, B; Kirsebom, H

2012-09-01

Removal of As(V) by adsorption from water solutions was studied using three different synthetic adsorbents. The adsorbents, (a) aluminium nanoparticles (Alu-NPs, polymers (polymer backbones of pure polyacrylamide (MIP-cryo) were of better stability than the amine containing polymer backbone (Alu-cryo). Both composites worked well in the studied pH range of pH 2-8. Adsorption tested in real wastewater spiked with arsenic showed that co-ions (nitrate, sulphate and phosphate) affected arsenic removal for Alu-cryo more than for MIP-cryo. Both composites still adsorbed well in the presence of counter-ions (copper and zinc) present at low concentrations (μg/l). The unchanged and selective adsorption in realistic water observed for MIP-cryo was concluded to be due to a successful imprinting, here controlled using a non-imprinted polymer (NIP). A development of MIP-cryo is needed, considering its low adsorption capacity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mixed-Penetrant Sorption in Ultra-Thin Films of Polymer of Intrinsic Microporosity PIM-1

KAUST Repository

Ogieglo, Wojciech; Furchner, Andreas; Ghanem, Bader; Ma, Xiao-Hua; Pinnau, Ingo; Wessling, Matthias

2017-01-01

Mixed penetrant sorption into ultra-thin films of a super-glassy polymer of intrinsic microporosity (PIM-1) was studied for the first time by using interference-enhanced in-situ spectroscopic ellipsometry. PIM-1 swelling and the concurrent changes in its refractive index were determined in ultra-thin (12 - 14 nm) films exposed to pure and mixed penetrants. The penetrants included water, n-hexane and ethanol and were chosen based on their significantly different penetrant-penetrant and penetrant-polymer affinities. This allowed studying microporous polymer responses at diverse ternary compositions and revealed effects such as competition for the sorption sites (for water / n-hexane or ethanol / n-hexane) or enhancement in sorption of typically weakly sorbing water in the presence of more highly sorbing ethanol. The results reveal details of the mutual sorption effects which often complicate comprehension of glassy polymers' behavior in applications such as high-performance membranes, adsorbents or catalysts. Mixed-penetrant effects are typically very challenging to study directly and their understanding is necessary owing to a broadly recognized inadequacy of simple extrapolations from measurements in pure component environment.

Mixed-Penetrant Sorption in Ultra-Thin Films of Polymer of Intrinsic Microporosity PIM-1

KAUST Repository

Ogieglo, Wojciech

2017-10-12

Mixed penetrant sorption into ultra-thin films of a super-glassy polymer of intrinsic microporosity (PIM-1) was studied for the first time by using interference-enhanced in-situ spectroscopic ellipsometry. PIM-1 swelling and the concurrent changes in its refractive index were determined in ultra-thin (12 - 14 nm) films exposed to pure and mixed penetrants. The penetrants included water, n-hexane and ethanol and were chosen based on their significantly different penetrant-penetrant and penetrant-polymer affinities. This allowed studying microporous polymer responses at diverse ternary compositions and revealed effects such as competition for the sorption sites (for water / n-hexane or ethanol / n-hexane) or enhancement in sorption of typically weakly sorbing water in the presence of more highly sorbing ethanol. The results reveal details of the mutual sorption effects which often complicate comprehension of glassy polymers\\' behavior in applications such as high-performance membranes, adsorbents or catalysts. Mixed-penetrant effects are typically very challenging to study directly and their understanding is necessary owing to a broadly recognized inadequacy of simple extrapolations from measurements in pure component environment.

PIV measurement of turbulent bubbly mixing layer flow with polymer additives

International Nuclear Information System (INIS)

Ning, T; Guo, F; Chen, B; Zhang, X

2009-01-01

Based on experimental investigation of single-phase turbulent mixing layer flow with polymer additives, bubbly mixing layer was experimentally investigated by PIV. The velocity ratio between high and low speed is 4:1 and the Reynolds number based on the velocity difference of two steams and hydraulic diameter of the channel ranges is 73333. Gas bubbles with about 0.5% gas fraction were injected into pure water mixing layer with/without polymer additives from three different parts at the end of the splitter plate. The comparison between single phase and bubbly mixing layer shows clearly that the dynamic development of mixing layer is great influenced by the bubble injection. Similar with single phase, the Reynolds stress and vorticity still concentrate in a coniform area of central mixing flow field part and the width will increase with increasing the Reynolds number. Mean Reynolds stress will decrease with bubble injection in high Reynolds numbers and the decreasing of Reynolds stress with polymer additives is much more than pure water case.

Applying the EBU R128 loudness standard in live-streaming sound sculptures

DEFF Research Database (Denmark)

Højlund, Marie Koldkjær; Riis, Morten S.; Rothmann, Daniel

2017-01-01

to preserve a natural sounding dynamic image from the varying sound sources that can be played back under varying conditions, an adaptation of the EBU R128 loudness measurement recommendation, originally developed for levelling non-real-time broadcast material, has been applied. The paper describes the Pure......This paper describes the development of a loudness-based compressor for live audio streams. The need for this device arose while developing the public sound art project The Overheard, which involves mixing together several live audio streams through a web based mixing interface. In order...

Alternative polymer separation technology by centrifugal force in a melted state

International Nuclear Information System (INIS)

Dobrovszky, Károly; Ronkay, Ferenc

2014-01-01

Highlights: • Waste separation should take place at high purity. • Developed a novel, alternative separation method, where the separation occurred in a melted state by centrifugal forces. • Possibility of separation two different plastics into neat fractions. • High purity fractions were established at granulates and also at prefabricated blend. • Results were verified by DSC, optical microscopy and Raman spectroscopy. - Abstract: In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy

Alternative polymer separation technology by centrifugal force in a melted state

Energy Technology Data Exchange (ETDEWEB)

Dobrovszky, Károly; Ronkay, Ferenc, E-mail: ronkay@pt.bme.hu

2014-11-15

Highlights: • Waste separation should take place at high purity. • Developed a novel, alternative separation method, where the separation occurred in a melted state by centrifugal forces. • Possibility of separation two different plastics into neat fractions. • High purity fractions were established at granulates and also at prefabricated blend. • Results were verified by DSC, optical microscopy and Raman spectroscopy. - Abstract: In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy.

New trends in the optical and electronic applications of polymers containing transition-metal complexes.

Science.gov (United States)

Liu, Shu-Juan; Chen, Yang; Xu, Wen-Juan; Zhao, Qiang; Huang, Wei

2012-04-13

Polymers containing transition-metal complexes exhibit excellent optical and electronic properties, which are different from those of polymers with a pure organic skeleton and combine the advantages of both polymers and metal complexes. Hence, research about this class of polymers has attracted more and more interest in recent years. Up to now, a number of novel polymers containing transition-metal complexes have been exploited, and significant advances in their optical and electronic applications have been achieved. In this article, we summarize some new research trends in the applications of this important class of optoelectronic polymers, such as chemo/biosensors, electronic memory devices and photovoltaic devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phase Relations and Miscibility in Polymer Blends Containing Copolymers.

Science.gov (United States)

1986-04-15

MacKnight, W. J ., Pure Appl. Chem. 52, 409 (1980). 36. Vukovic , R., Kuresevic, V., Karasz, F. E., and MacKnight, W. J ., Thermochim. Acta 54, 349 (1982). 37... Vukovic , R., Karasz, F. E., and MacKnight, W. J ., Polymer 24, 529 (1983). 38. Vukovic , R., Karasz, F. E., and MacKnight, W. J ., J . Appl. Polymer Sci...28, 219 (1983). 39. Zacharius, S. L., ten Brinke, G., MacKnight, W. J ., and Karasz, F. E., Macromolecules 16, 381 (1983). 40. Vukovic , R., Kuresevic

Improved polymer nanocomposite dielectric breakdown performance through barium titanate to epoxy interface control

Energy Technology Data Exchange (ETDEWEB)

Siddabattuni, Sasidhar [Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Chemistry Department, 400W. 11th Street, Rolla, MO 65409 (United States); Schuman, Thomas P., E-mail: tschuman@mst.edu [Missouri University of Science and Technology (formerly the University of Missouri-Rolla), Chemistry Department, 400W. 11th Street, Rolla, MO 65409 (United States); Dogan, Fatih [Missouri University of Science and Technology, Materials Science and Engineering Department, 1400N. Bishop Avenue, Rolla, MO 65409 (United States)

2011-11-15

Highlights: > A covalent filler-matrix interface improves the dielectric properties of a polymer-particle nanocomposite dielectric. > A covalent interface reduced the polymer free volume around the nanoparticles as assessed through T{sub g} measurements. > Composite T{sub g} was raised and breakdown strength improved for nanocomposites with a covalent polymer-particle interface. > A larger Maxwell-Wagner (MW) relaxation correlated with reduced breakdown strengths and energy storage densities. > The MW relaxation could be considered a dielectric defect regarding breakdown strength and energy storage density. - Abstract: A composite approach to dielectric design has the potential to provide improved permittivity as well as high breakdown strength and thus afford greater electrical energy storage density. Interfacial coupling is an effective approach to improve the polymer-particle composite dielectric film resistance to charge flow and dielectric breakdown. A bi-functional interfacial coupling agent added to the inorganic oxide particles' surface assists dispersion into the thermosetting epoxy polymer matrix and upon composite cure reacts covalently with the polymer matrix. The composite then retains the glass transition temperature of pure polymer, provides a reduced Maxwell-Wagner relaxation of the polymer-particle composite, and attains a reduced sensitivity to dielectric breakdown compared to particle epoxy composites that lack interfacial coupling between the composite filler and polymer matrix. Besides an improved permittivity, the breakdown strength and thus energy density of a covalent interface nanoparticle barium titanate in epoxy composite dielectric film, at a 5 vol.% particle concentration, was significantly improved compared to a pure polymer dielectric film. The interfacially bonded, dielectric composite film had a permittivity {approx}6.3 and at a 30 {mu}m thickness achieved a calculated energy density of 4.6 J/cm{sup 3}.

Improved polymer nanocomposite dielectric breakdown performance through barium titanate to epoxy interface control

International Nuclear Information System (INIS)

Siddabattuni, Sasidhar; Schuman, Thomas P.; Dogan, Fatih

2011-01-01

Highlights: → A covalent filler-matrix interface improves the dielectric properties of a polymer-particle nanocomposite dielectric. → A covalent interface reduced the polymer free volume around the nanoparticles as assessed through T g measurements. → Composite T g was raised and breakdown strength improved for nanocomposites with a covalent polymer-particle interface. → A larger Maxwell-Wagner (MW) relaxation correlated with reduced breakdown strengths and energy storage densities. → The MW relaxation could be considered a dielectric defect regarding breakdown strength and energy storage density. - Abstract: A composite approach to dielectric design has the potential to provide improved permittivity as well as high breakdown strength and thus afford greater electrical energy storage density. Interfacial coupling is an effective approach to improve the polymer-particle composite dielectric film resistance to charge flow and dielectric breakdown. A bi-functional interfacial coupling agent added to the inorganic oxide particles' surface assists dispersion into the thermosetting epoxy polymer matrix and upon composite cure reacts covalently with the polymer matrix. The composite then retains the glass transition temperature of pure polymer, provides a reduced Maxwell-Wagner relaxation of the polymer-particle composite, and attains a reduced sensitivity to dielectric breakdown compared to particle epoxy composites that lack interfacial coupling between the composite filler and polymer matrix. Besides an improved permittivity, the breakdown strength and thus energy density of a covalent interface nanoparticle barium titanate in epoxy composite dielectric film, at a 5 vol.% particle concentration, was significantly improved compared to a pure polymer dielectric film. The interfacially bonded, dielectric composite film had a permittivity ∼6.3 and at a 30 μm thickness achieved a calculated energy density of 4.6 J/cm 3 .

Boiling characteristics of dilute polymer solutions and implications for the suppression of vapor explosions

Energy Technology Data Exchange (ETDEWEB)

Bang, K.H.; Kim, M.H. [Univ. of Science and Technology, Pohang (Korea, Republic of)

1995-09-01

Quenching experiments of hot solid spheres in dilute aqueous solutions of polyethylene oxide polymer have been conducted for the purpose of investigating the physical mechanisms of the suppression of vapor explosions in this polymer solutions. Two spheres of 22.2mm and 9.5mm-diameter were tested in the polymer solutions of various concentrations at 30{degrees}C. Minimum film boiling temperature ({Delta}T{sub MFB}) in this highly-subcooled liquid rapidly decreased from over 700{degrees}c for pure water to about 150{degrees}C as the polymer concentration was increased up to 300ppm for 22.2mm sphere, and it decreased to 350{degrees}C for 9.5mm sphere. This rapid reduction of minimum film boiling temperature in the PEO aqueous solutions can explain its ability of the suppression of spontaneous vapor explosions. The ability of suppression of vapor explosions by dilute polyethylene oxide solutions against an external trigger pressure was tested by dropping molten tin into the polymer solutions at 25{degrees}C. It was observed that in 50ppm solutions more mass fragmented than in pure water, but produced weaker explosion pressures. The explosion was completely suppressed in 300ppm solutions with the external trigger. The debris size distributions of fine fragments smaller than 0.7mm were shown almost identical regardless of the polymer concentrations.

Synthesis of new water-soluble metal-binding polymers: Combinatorial chemistry approach. 1997 mid-year progress report

International Nuclear Information System (INIS)

Smith, B.F.

1997-01-01

'The first objective of this research is to develop rapid discovery and optimization approaches to new water-soluble chelating polymers. A byproduct of the development approach will be the new, selective, and efficient metal-binding agents. The second objective is to evaluate the concept of using water and organic soluble polymers as new solid supports for combinatorial synthesis. The technology under development, Polymer Filtration (PF), is a technique to selectively remove or recover hazardous and valuable metal ions and radionuclides from various dilute aqueous streams. Not only can this technology be used to remediate contaminated soils and solid surfaces and treat aqueous wastes, it can also be incorporated into facilities as a pollution prevention and waste minimization technology. Polymer Filtration uses water-soluble metal-binding polymers to sequester metal ions in dilute solution. The water-soluble polymers have a sufficiently large molecular size that they can be separated and concentrated using commercial ultrafiltration technology. Water, small organic molecules, and unbound metals pass freely through the ultrafiltration membrane while concentrating the metal-binding polymer. The polymers can then be reused by changing the solution conditions to release the metal ions. The metal-ions are recovered in concentrated form for recycle or disposal using a diafiltration process. The water-soluble polymer can be recycled for further aqueous-stream processing. To advance Polymer Filtration technology to the selectivity levels required for DOE needs. fixture directions in Polymer Filtration must include rapid development, testing, and characterization of new metal-binding polymers. The development of new chelating molecules can be equated to the process of new drugs or new materials discovery. Thus, the authors want to build upon and adapt the combinatorial chemistry approaches developed for rapid molecule generation for the drug industry to the rapid

Large energy absorption in Ni-Mn-Ga/polymer composites

International Nuclear Information System (INIS)

Feuchtwanger, Jorge; Richard, Marc L.; Tang, Yun J.; Berkowitz, Ami E.; O'Handley, Robert C.; Allen, Samuel M.

2005-01-01

Ferromagnetic shape memory alloys can respond to a magnetic field or applied stress by the motion of twin boundaries and hence they show large hysteresis or energy loss. Ni-Mn-Ga particles made by spark erosion have been dispersed and oriented in a polymer matrix to form pseudo 3:1 composites which are studied under applied stress. Loss ratios have been determined from the stress-strain data. The loss ratios of the composites range from 63% to 67% compared to only about 17% for the pure, unfilled polymer samples

Nonequilibrium thermodynamics of dilute polymer solutions in flow.

Science.gov (United States)

Latinwo, Folarin; Hsiao, Kai-Wen; Schroeder, Charles M

2014-11-07

Modern materials processing applications and technologies often occur far from equilibrium. To this end, the processing of complex materials such as polymer melts and nanocomposites generally occurs under strong deformations and flows, conditions under which equilibrium thermodynamics does not apply. As a result, the ability to determine the nonequilibrium thermodynamic properties of polymeric materials from measurable quantities such as heat and work is a major challenge in the field. Here, we use work relations to show that nonequilibrium thermodynamic quantities such as free energy and entropy can be determined for dilute polymer solutions in flow. In this way, we determine the thermodynamic properties of DNA molecules in strong flows using a combination of simulations, kinetic theory, and single molecule experiments. We show that it is possible to calculate polymer relaxation timescales purely from polymer stretching dynamics in flow. We further observe a thermodynamic equivalence between nonequilibrium and equilibrium steady-states for polymeric systems. In this way, our results provide an improved understanding of the energetics of flowing polymer solutions.

Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

International Nuclear Information System (INIS)

Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Satyanarayana, N.; Venkateswarlu, M.

2014-01-01

Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl 2 O 4 )] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF 6 in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl 2 O 4 exhibits high ionic conductivity of 2.80 × 10 −3 S/cm at room temperature. The charge-discharge capacity of Li/LiCoO 2 coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl 2 O 4 ] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator

Direct Contact Membrane Distillation of Dairy Process Streams

Directory of Open Access Journals (Sweden)

Mike Weeks

2011-01-01

Full Text Available Membrane distillation (MD was applied for the concentration of a range of dairy streams, such as whole milk, skim milk and whey. MD of a pure lactose solution was also investigated. Direct contact MD (DCMD mode experiments were carried out in continuous concentration mode, keeping the warm feed/retentate and cold permeate stream temperatures at 54 °C and 5 °C respectively. Performance in terms of flux and retention was assessed. The flux was found to decrease with an increase of dry-matter concentration in the feed. Retention of dissolved solids was found to be close to 100% and independent of the dry-matter concentration in the feed. Fourier Transform Infrared Spectroscopy (FTIR of the fouled membranes confirms organics being present in the fouling layer.

Battling memory requirements of array programming through streaming

DEFF Research Database (Denmark)

Kristensen, Mads Ruben Burgdorff; Avery, James Emil; Blum, Troels

2016-01-01

A barrier to efficient array programming, for example in Python/NumPy, is that algorithms written as pure array operations completely without loops, while most efficient on small input, can lead to explosions in memory use. The present paper presents a solution to this problem using array streaming......, implemented in the automatic parallelization high-performance framework Bohrium. This makes it possible to use array programming in Python/NumPy code directly, even when the apparent memory requirement exceeds the machine capacity, since the automatic streaming eliminates the temporary memory overhead...... by performing calculations in per-thread registers. Using Bohrium, we automatically fuse, JIT-compile, and execute NumPy array operations on GPGPUs without modification to the user programs. We present performance evaluations of three benchmarks, all of which show dramatic reductions in memory use from...

Dichroic dye-dependent studies in guest-host polymer-dispersed liquid crystal films

Energy Technology Data Exchange (ETDEWEB)

Malik, Praveen, E-mail: pmalik100@yahoo.co [Department of Physics, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar 144011, Punjab (India); Raina, K.K. [Liquid Crystal Group, Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India)

2010-01-01

Guest-host polymer-dispersed liquid crystal (GHPDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic dye (anthraquinone blue) by polymerization-induced phase separation (PIPS) technique. Non-ionic dichroic dye (1%, 2% and 4% wt./wt. ratio) was taken as guest in PDLC host. Polarizing microscopy shows that in the absence of electric field, liquid crystal (LC) droplets in polymer matrix mainly exhibit bipolar configuration, however, relatively at higher field, maltese-type crosses were observed. Our results show that approx1% dye-doped PDLC film shows better transmission and faster response times over pure polymer-dispersed nematic liquid crystal (PDNLC) and higher concentrated (2% and 4%) GHPDLC films.

Dichroic dye-dependent studies in guest-host polymer-dispersed liquid crystal films

International Nuclear Information System (INIS)

Malik, Praveen; Raina, K.K.

2010-01-01

Guest-host polymer-dispersed liquid crystal (GHPDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic dye (anthraquinone blue) by polymerization-induced phase separation (PIPS) technique. Non-ionic dichroic dye (1%, 2% and 4% wt./wt. ratio) was taken as guest in PDLC host. Polarizing microscopy shows that in the absence of electric field, liquid crystal (LC) droplets in polymer matrix mainly exhibit bipolar configuration, however, relatively at higher field, maltese-type crosses were observed. Our results show that ∼1% dye-doped PDLC film shows better transmission and faster response times over pure polymer-dispersed nematic liquid crystal (PDNLC) and higher concentrated (2% and 4%) GHPDLC films.

Testing of a Peroxidation Systems, Inc. perox-pure SSB-30

International Nuclear Information System (INIS)

Hodgson, K.M.; Lunsford, T.R.

1994-02-01

A facility is being designed and built at the US Department of Energy (DOE) Hanford Site to treat water containing a variety of organic and inorganic compounds. An ultraviolet light/hydrogen peroxide system, manufactured by Peroxidation Systems, Inc. (PSI), has been chosen to destroy the organic compounds in the feed stream. The PSI perox-pure trademark model SSB-30 has been tested by the Westinghouse Hanford Company (WHC) to provide data for permit documentation and to determine appropriate operating conditions. The destruction of the organic compounds was demonstrated with several feed compositions at different ultraviolet light exposures and hydrogen peroxide concentrations

Magnetic composite beads for sorption of cesium ions from aqueous streams

International Nuclear Information System (INIS)

Shinde, Rakesh N.; Pandey, A.K.; Acharya, R.; Rajurkar, N.S.

2014-01-01

Magnetic separation of metal ions is one of the promising methods due to simple, fast, efficient and cost effective technology. Highly selective magnetic sorbents can be designed by immobilizing functional groups in magnetic carrier which binds to the target specific ions. In the present work chitosan-(3-aminopropyl) triethoxysilane (APTS)- copperferrocyanide (CFC) composite beads have been synthesized for sorption of 137 Cs ions from aqueous streams. Physical characterization of the best resulted polymer beads was carried out by SEM-EDX and VSM technique. Sorption of Cs ions in the various magnetic polymer beads were studied in different aqueous condition by 137 Cs (662 KeV) radiotracer assay

Dielectric behavior of CaCu3Ti4O12: Poly Vinyl Chloride ceramic polymer composites at different temperature and frequencies

Directory of Open Access Journals (Sweden)

Ajay Pratap Singh

2016-12-01

Full Text Available In this study, the efforts have been made to obtain relatively high dielectric constant polymer-ceramic composite by incorporating the giant dielectric constant material, calcium copper titanate (CCTO in a PVC polymer matrix. We have prepared composites of CaCu3Ti4O12 (CCTO ceramic and Poly Vinyl Chloride (PVC polymer in various ratios (by volume in addition to pure CCTO. For this, CCTO was prepared by the conventional oxide route (solid-state reaction method. The structural, the microstructural and the dielectric properties of the composites were studied using X-ray diffraction, Scanning Electron Microscope, and impedance analyzer respectively. The study of dielectric constant and dielectric loss of the pure CCTO and the composites reveal that there is good range of dielectric constants and dielectric losses for the studied composites. The pure sample of CCTO exhibits giant dielectric constant at low frequency within the studied temperature range. As frequency increases, dielectric constant drastically decreases and approaching a constant value at 1 MHz. Above the intermediate temperature, the dielectric constant and dielectric loss for pure CCTO is more frequency dependent than its composites.

Colloidal synthesis of BaF2 nanoparticles and their application as fillers in polymer nanocomposites

Science.gov (United States)

Sathyamurthy, Srivatsan; Tuncer, Enis; More, Karren L.; Gu, Baohua; Sauers, Isidor; Paranthaman, M. Parans

2012-03-01

Nanoparticles of pure and Eu-doped BaF2 have been prepared through sol-gel colloidal synthesis. In addition, BaF2-filled PMMA polymer nanocomposites were fabricated and dielectric properties were measured. The as-synthesized pure and Eu-doped BaF2 nanoparticles were analyzed by both X-ray diffraction and transmission electron microscopy and consisted of crystalline BaF2 particles with an average diameter of 13.6 nm with a standard deviation of about ±2.4 nm. The photoluminescence properties of the pure and Eu-doped (2%, 4% and 8%) nanoparticles showed characteristic emission of Eu3+ (5D0→7F J ( J=1-4) transitions). We also measured significantly enhanced dielectric breakdown strength of up to 30% for BaF2 nanocomposites over the unfilled PMMA polymer. This study thus offers some promise of sol-gel synthesis of nanocomposite dielectrics with great potential for use as electrical insulation materials in cryogenic high-voltage applications.

Colloidal synthesis of BaF2 nanoparticles and their application as fillers in polymer nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Sathyamurthy, Srivatsan [ORNL; Tuncer, Enis [ORNL; More, Karren Leslie [ORNL; Gu, Baohua [ORNL; Sauers, Isidor [ORNL; Paranthaman, Mariappan Parans [ORNL

2012-01-01

Nanoparticles of pure and Eu-doped BaF2 have been prepared through sol-gel colloidal synthesis. In addition, BaF2 filled PMMA polymer nanocomposites were fabricated and dielectric properties were measured. The as-synthesized pure and Eu-doped BaF2 nanoparticles were analyzed by both X-ray diffraction and transmission electron microscopy and consisted of crystalline BaF2 particles with an average diameter of 13.6 nm with a standard deviation of about 2.4 nm. The photoluminescence properties of the pure and Eu-doped (2%, 4% and 8%) nanoparticles showed characteristic emission of Eu3+ (5D0 7FJ (J=1-4) transitions). We also measured significantly enhanced dielectric breakdown strength of up to 30% for BaF2 nanocomposites over the unfilled PMMA polymer. This study thus offers some promise of sol-gel synthesis of nanocomposite dielectrics with great potential for use as electrical insulation materials in cryogenic high voltage applications.

Modeling of nanosecond pulsed laser processing of polymers in air and water

DEFF Research Database (Denmark)

Marla, Deepak; Zhang, Yang; Hattel, Jesper H.

2018-01-01

radiation (λ = 1064 nm) of nanosecond pulse duration. The laser–polymer interaction at such wavelengths is purely photo-thermal in nature and the laser–plasma interaction is assumed to occur mainly by inverse-bremsstrahlung photon absorption. The computational model is based on the finite volume method......Laser ablation of polymers in water is known to generate distinct surface characteristics as compared to that in air. In order to understand the role of ambient media during laser ablation of polymers, this paper aims to develop a physics-based model of the process considering the effect of ambient...... media. Therefore, in the present work, models are developed for laser ablation of polymers in air and water considering all the relevant physical phenomena such as laser–polymer interaction, plasma generation, plasma expansion and plasma shielding. The current work focuses on near-infrared laser...

Pressure-dependent pure- and mixed-gas permeation properties of Nafion®

KAUST Repository

Mukaddam, Mohsin Ahmed

2016-04-20

The permeation properties of Nafion® at 35 °C are presented for pure gases H2, N2, O2, CH4, CO2, C2H6 and C3H8, as a function of pressure between 2 and 20 atm. The effect of pressure on permeability and selectivity is analyzed to understand two observed phenomena: compression and plasticization. In pure-gas experiments, at increasing feed pressure, compression of the polymer matrix reduced the permeability of low-sorbing penetrants H2, N2, O2, and CH4. In contrast, permeabilities of more soluble penetrants CO2 and C2H6 increased by 18% and 46% respectively, as plasticization effects overcame compression effects. Permeability of C3H8 decreased slightly with increasing pressure up to 4.6 atm as a result of compression, then increased by 3-fold at 9 atm as a result of plasticization associated with high C3H8 solubility. Binary CO2/CH4 (50:50) mixed-gas experiments at total feed pressures up to 36 atm quantified the effect of CO2 plasticization on separation performance. At 10 atm CO2 partial pressure, CH4 permeability increased by 23% relative to its pure-gas value of 0.078 Barrer, while CO2 permeability decreased by 28%. Consequently, CO2/CH4 selectivity decreased to 19, i.e., 42% below its pure-gas value of 32.

Efficient polymer white-light-emitting diodes with a single-emission layer of fluorescent polymer blend

International Nuclear Information System (INIS)

Niu Qiaoli; Xu Yunhua; Jiang Jiaxing; Peng Junbiao; Cao Yong

2007-01-01

Efficient polymer white-light-emitting diodes (WPLEDs) have been fabricated with a single layer of fluorescent polymer blend. The device structure consists of ITO/PEDOT/PVK/emissive layer/Ba/Al. The emissive layer is a blend of poly(9,9-dioctylfluorene) (PFO), phenyl-substituted PPV derivative (P-PPV) and a copolymer of 9,9-dioctylfluorene and 4,7-di(4-hexylthien-2-yl)-2,1,3-benzothiadiazole (PFO-DHTBT), which, respectively, emits blue, green and red light. The emission of pure and efficient white light was implemented by tuning the blend weight ratio of PFO: P-PPV: PFO-DHTBT to 96:4:0.4. The maximum current efficiency and luminance are, respectively, 7.6 cd/A at 6.7 V and 11930 cd/m 2 at 11.2 V. The CIE coordinates of white-light emission were stable with the drive voltages

Experimental evaluation of the pure configurational stress assumption in the flow dynamics of entangled polymer melts

DEFF Research Database (Denmark)

Rasmussen, Henrik K.; Bejenariu, Anca Gabriela; Hassager, Ole

2010-01-01

to the flow in the non-linear flow regime. This has allowed highly elastic measurements within the limit of pure orientational stress, as the time of the flow was considerably smaller than the Rouse time. A Doi-Edwards [J. Chem. Soc., Faraday Trans. 2 74, 1818-1832 (1978)] type of constitutive model...... with the assumption of pure configurational stress was accurately able to predict the startup as well as the reversed flow behavior. This confirms that this commonly used theoretical picture for the flow of polymeric liquids is a correct physical principle to apply. c 2010 The Society of Rheology. [DOI: 10.1122/1.3496378]...

Polymer Thin Film Stabilization.

Science.gov (United States)

Costa, A. C.; Oslanec, R.; Composto, R. J.; Vlcek, P.

1998-03-01

We study the dewetting dynamics of thin polystyrene (PS) films deposited on silicon oxide surfaces using optical (OM) and atomic force (AFM) microscopes. Quantitative analysis of the hole diameter as a function of annealing time at 175^oC shows that blending poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) with PS acts to dramatically slow down the dewetting rate and even stops holes growth before they impinge. AFM studies show that the hole floor is smooth for a pure PS film but contains residual polymer for the blend. At 5% vol., a PS-b-PMMA with high molar mass and low PMMA is a more effective stabilizing agent than a low molar mass/high PMMA additive. The optimum copolymer concentration is 3% vol. beyond which film stability doesn't improve. Although dewetting is slowed down relative to pure PS, PS/PS-b-PMMA bilayers dewet at a faster rate than blends having the same overall additive concentration.

Purification of Polymer-Grade Fumaric Acid from Fermented Spent Sulfite Liquor

Directory of Open Access Journals (Sweden)

Diogo Figueira

2017-04-01

Full Text Available Fumaric acid is a chemical building block with many applications, namely in the polymer industry. The fermentative production of fumaric acid from renewable feedstock is a promising and sustainable alternative to petroleum-based chemical synthesis. The use of existing industrial side-streams as raw-materials within biorefineries potentially enables production costs competitive against current chemical processes, while preventing the use of refined sugars competing with food and feed uses and avoiding purposely grown crops requiring large areas of arable land. However, most industrial side streams contain a diversity of molecules that will add complexity to the purification of fumaric acid from the fermentation broth. A process for the recovery and purification of fumaric acid from a complex fermentation medium containing spent sulfite liquor (SSL as a carbon source was developed and is herein described. A simple two-stage precipitation procedure, involving separation unit operations, pH and temperature manipulation and polishing through the removal of contaminants with activated carbon, allowed for the recovery of fumaric acid with 68.3% recovery yield with specifications meeting the requirements of the polymer industry. Further, process integration opportunities were implemented that allowed minimizing the generation of waste streams containing fumaric acid, which enabled increasing the yield to 81.4% while keeping the product specifications.

Sensing of environmental pollutant by conductive composite from prepared from hyperbranched polymer-grafted carbon black and crystalline polymer

International Nuclear Information System (INIS)

Taniguchi, Y.; Chen, J.; Ogawa, M.; Yokoyama, K.; Shimizu, H.; Tsubokawa, N.; Maekawa, Y.; Yoshida, M.

2002-01-01

Complete text of publication follows. The hyperbranched (HB) polymer-grafted (PG) carbon blacks (CB) have the possibility of utilizing as a support of catalyst and enzyme, and a curing agent of epoxy resin, because they have much terminal amino or hydroxyl groups. The postgrafting of crystalline polymer onto HB PG CB and the sensing of environmental pollutant by the conductive composite prepared from the polymer-postgrafted CB was discussed. The grafting of poly(amidoamide) onto CB surface was achieved by repeating either Michael addition of methyl acrylate to amino group on the surface or the amidation of the resulting terminal methyl ester group with ethylene diamine. HB polyester onto CB surface was grafted by stepwise growth of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) from surface carboxyl and hydroxyl groups on CB as a core in the presence of p-toluenesulfonic acid (p-TSA). The one-pot grafting of HB polyester onto CB as core was also achieved by the polycondensation of bis-MPA in the presence of p-TSA. Postgrafting of crystalline polymer onto HB polymer-grafted CB was achieved by the reaction of terminal amino or hydroxyl groups of grafted chain with COCl-terminated crystalline polymer. The electric resistance of the composite prepared from crystalline polymer-postgrafted CB was found to increase drastically in hexane, containing environmental pollutant, such as chloroform and trichloroethane, and returned immediately to the initial resistance when it was transferred into pure hexane. Based on the above results, it is concluded that the composite can be used as a novel sensor for environmental pollutant in solution

Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

DEFF Research Database (Denmark)

Qingfeng, Li; Hjuler, Hans Aage; Bjerrum, Niels

2000-01-01

Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and polybenzimidazole (PBI) polymer electrolytes in a temperature range up to 190 degrees C. Compared with pure H3PO4, the combination of H3PO4 and polymer electrolytes can significantly...... membrane fuel cell based on H3PO4-doped PBI for operation at temperatures between 150 and 200 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved....

Improved antifouling properties of polymer membranes using a ‘layer-by-layer’ mediated method

KAUST Repository

Chen, Lin; Thé rien-Aubin, Hé loï se; Wong, Mavis C. Y.; Hoek, Eric M. V.; Ober, Christopher K.

2013-01-01

Polymeric reverse osmosis membranes were modified with antifouling polymer brushes through a 'layer by layer' (LBL) mediated method. Based on pure physical electrostatic interaction, the attachment of LBL films did not alter separation performance

A numerical model to simulate foams during devolatilization of polymers

Science.gov (United States)

Khan, Irfan; Dixit, Ravindra

2014-11-01

Customers often demand that the polymers sold in the market have low levels of volatile organic compounds (VOC). Some of the processes for making polymers involve the removal of volatiles to the levels of parts per million (devolatilization). During this step the volatiles are phase separated out of the polymer through a combination of heating and applying lower pressure, creating foam with the pure polymer in liquid phase and the volatiles in the gas phase. The efficiency of the devolatilization process depends on predicting the onset of solvent phase change in the polymer and volatiles mixture accurately based on the processing conditions. However due to the complex relationship between the polymer properties and the processing conditions this is not trivial. In this work, a bubble scale model is coupled with a bulk scale transport model to simulate the processing conditions of polymer devolatilization. The bubble scale model simulates the nucleation and bubble growth based on the classical nucleation theory and the popular ``influence volume approach.'' As such it provides the information of bubble size distribution and number density inside the polymer at any given time and position. This information is used to predict the bulk properties of the polymer and its behavior under the applied processing conditions. Initial results of this modeling approach will be presented.

Molecular motion in polymer electrolytes. An investigation of methods for improving the conductivity of solid polymer electrolytes

International Nuclear Information System (INIS)

Webster, Mark Ian

2002-01-01

Three methods were explored with a view to enhancing the ionic conductivity of polymer electrolytes; namely the addition of an inert, inorganic filler, the addition of a plasticizer and the incorporation of the electrolyte in the pores of silica matrices. There have been a number of reports, which suggest the addition of nanocrystalline oxides to polymer electrolytes increases the ionic conductivities by about a factor of two. In this thesis studies of the polymer electrolyte NaSCN.P(EO) 8 with added nanocrystalline alumina powder are reported which show no evidence of enhanced conductivity. The addition of a plasticizer to polymer electrolytes will increase the ionic conductivity. A detailed study was made of the polymer electrolytes LiT.P(EO) 10 and LiClO 4 .P(EO) 10 with added ethylene carbonate plasticizer. The conductivities showed an enhancement, however this disappeared on heating under vacuum. The present work suggests that the plasticised system is not thermodynamically stable and will limit the applications of the material. A series of samples were prepared from the polymer electrolyte LiT.P(EO) 8 and a range of porous silicas. The silicas were selected to give a wide range of pore size and included Zeolite Y, ZSM5, mesoporous silica and a range of porous glasses. This gave pore sizes from less than one nm to 50 nm. A variety of experiments, including X-ray diffraction, DSC and NMR, showed that the polymer electrolyte entered to pores of the silica. As a result the polymer was amorphous and the room temperature conductivity was enhanced. The high temperature conductivity was not increased above that for the pure electrolyte. The results suggest that this could be employed in applications, however would require higher conducting electrolytes to be of practical benefit. (author)

Polymer solidification national program

International Nuclear Information System (INIS)

Kalb, P.D.; Colombo, P.

1993-04-01

Brookhaven National Laboratory (BNL) has developed several new and innovative polymer processes for the solidification of low-level radioactive, hazardous and mixed wastes streams. Polyethylene and modified sulfur cement solidification technologies have undergone steady, gradual development at BNL over the past nine years. During this time they have progressed through each of the stages necessary for logical technology maturation: from process conception, parameter optimization, waste form testing, evaluation of long-term durability, economic analysis, and scale-up feasibility. This technology development represents a significant investment which can potentially provide DOE with both short- and long-term savings

Fabrication and Photostability of Rhodamine-6G Gold Nanoparticle Doped Polymer Optical Fiber

International Nuclear Information System (INIS)

Sebastian, Suneetha; Ajina, C; Vallabhan, C. P. G; Nampoori, V. P. N.; Radhakrishnan, P.; Kailasnath, M.

2013-01-01

We report on fabrication of a rhodamine-6G-gold-nanoparticle doped polymer optical fiber. The gold nanoparticle is synthesized directly into the monomer solution of the polymer using laser ablation synthesis in liquid. The size of the particle is found from the transmission electron microscopy. Rhodamine-6G is then mixed with the nanoparticle-monomer solution and optical characterization of the solution is investigated. It is found that there is a pronounced quenching of fluorescence of rhodamine 6G due to fluorescence resonance energy transfer. The monomer solution containing rhodamine 6G and gold nanoparticles is now made into a cylindrical rod and drawn into a polymer optical fiber. Further, the photostability is calculated with respect to the pure dye doped polymer optical fiber

Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

Science.gov (United States)

Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

2016-10-01

To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems

Spray process for the recovery of CO.sub.2 from a gas stream and a related apparatus

Science.gov (United States)

Soloveichik, Grigorii Lev; Perry, Robert James; Wood, Benjamin Rue; Genovese, Sarah Elizabeth

2014-02-11

A method for recovering carbon dioxide (CO.sub.2) from a gas stream is disclosed. The method includes the step of reacting CO.sub.2 in the gas stream with fine droplets of a liquid absorbent, so as to form a solid material in which the CO.sub.2 is bound. The solid material is then transported to a desorption site, where it is heated, to release substantially pure CO.sub.2 gas. The CO.sub.2 gas can then be collected and used or transported in any desired way. A related apparatus for recovering carbon dioxide (CO.sub.2) from a gas stream is also described herein.

Streams with Strahler Stream Order

Data.gov (United States)

Minnesota Department of Natural Resources — Stream segments with Strahler stream order values assigned. As of 01/08/08 the linework is from the DNR24K stream coverages and will not match the updated...

New Splitting Criteria for Decision Trees in Stationary Data Streams.

Science.gov (United States)

Jaworski, Maciej; Duda, Piotr; Rutkowski, Leszek; Jaworski, Maciej; Duda, Piotr; Rutkowski, Leszek; Rutkowski, Leszek; Duda, Piotr; Jaworski, Maciej

2018-06-01

The most popular tools for stream data mining are based on decision trees. In previous 15 years, all designed methods, headed by the very fast decision tree algorithm, relayed on Hoeffding's inequality and hundreds of researchers followed this scheme. Recently, we have demonstrated that although the Hoeffding decision trees are an effective tool for dealing with stream data, they are a purely heuristic procedure; for example, classical decision trees such as ID3 or CART cannot be adopted to data stream mining using Hoeffding's inequality. Therefore, there is an urgent need to develop new algorithms, which are both mathematically justified and characterized by good performance. In this paper, we address this problem by developing a family of new splitting criteria for classification in stationary data streams and investigating their probabilistic properties. The new criteria, derived using appropriate statistical tools, are based on the misclassification error and the Gini index impurity measures. The general division of splitting criteria into two types is proposed. Attributes chosen based on type- splitting criteria guarantee, with high probability, the highest expected value of split measure. Type- criteria ensure that the chosen attribute is the same, with high probability, as it would be chosen based on the whole infinite data stream. Moreover, in this paper, two hybrid splitting criteria are proposed, which are the combinations of single criteria based on the misclassification error and Gini index.

Nanomodified polymer composites: Thermophysical and physico-mechanical properties

Science.gov (United States)

Shchegolkov, Alexander; Shchegolkov, Alexey; Dyachkova, Tatyana; Borovskikh, Pavel

2017-11-01

The paper presents the results of investigation of thermophysical and physicomechanical properties of polymer-based composites modified with paraffin and carbon nanotubes (CNTs) mixture. Thermal conductivity of composites based on polyethylene, fluoroplastic, polyvinyl chloride (PVC) is 0.48, 0.42 and 0.36 W/(m.°C), respectively, compared to thermal conductivity of pure paraffin - 0.25 W/(m.°C). It has been revealed that for materials heat capacity the polymer matrix determines the position of the maximum point on temperature dependence having extreme nature. Temperature changes in composites volume do not exceed 3% from the initial state to the phase transition, that allows them to be used in a combination with other materials.

Pure- and Mixed-Gas Transport Study of Nafion® and Its Fe3+-Substituted Derivative for Membrane-Based Natural Gas Applications

KAUST Repository

Mukaddam, Mohsin A.

2016-05-26

in Nafion® was almost 2.5 times lower than that of typical hydrocarbon polymers, highlighting Nafion’s® effectiveness in resisting high-solubility induced plasticization. Additionally, Nafion® showed extraordinarily high permselectivities between small gases (He, H2, CO2) and large hydrocarbon gases (C1+): He/CH4 = 445, He/C3H8 = 7400, CO2/CH4 = 28, CO2/C3H8 = 460, H2/CH4 = 84 and H2/C3H8 = 1400 owing to its tightly packed chain domains. These high selectivities could potentially be harnessed for helium recovery and CO2 removal in natural gas applications, and hydrogen recovery from refinery gas streams. Pressure-dependent pure- and mixed-gas permeabilities in Nafion® were determined at 35 °C. Nafion® demonstrated two divergent pressure-dependent permeability phenomena: gas compression and plasticization. In pure-gas experiments, the permeability of the permanent gases H2, O2, N2 and CH4 decreased with increasing pressure due to polymer compression, whereas the permeability of the more condensable gases CO2, C2H6 and C3H8 increased dramatically due to solubility-induced plasticization. Binary CO2/CH4 (50:50) mixed-gas experiments showed reduced performance with up to 2-fold increases in CH4 permeability from 0.075 to 0.127 Barrer, and a 45% drop in selectivity (from 26 to 14), between 2 and 36 atm total pressure as a result of CO2-induced plasticization. At a typical NG CO2 partial pressure of 10 atm, Nafion® exhibited 24% lower CO2/CH4 selectivity of 19, with a 4-fold lower CO2 permeability of 1.8 Barrer relative to a commercial cellulose acetate (CA) membrane. Ternary CO2/CH4/C3H8 (30:50:20) experiments quantified the effect of CO2 and C3H8 plasticization. The presence of C3H8 reduced CO2 permeability further due to a competitive sorption effect causing a 31% reduction in CO2/CH4 selectivity, relative to its pure-gas value of 29, at 16 atm total feed pressure. The strong cation-exchanging sulfonate groups in Nafion® provided an opportunity to tailor the

Investigation of a polymer-dispersed liquid crystal system by NMR diffusometry and relaxometry

Energy Technology Data Exchange (ETDEWEB)

Tang, Mingxue

2013-02-26

Polymer-dispersed liquid crystals (PDLCs) are polymer composites containing a dispersion of liquid crystal droplets in polymer networks. PDLCs have attracted much attention due to their unique properties and potential usage. The properties of PDLCs depend on the degree of phase separation and the size of liquid crystal droplets. To investigate the structure will help us to better understand and optimize PDLCs.The main aim of this PhD thesis was to investigate PDLCs by NMR techniques. Diffusion constants and spin-lattice relaxation times in the laboratory (T{sub 1}) and rotating frame (T{sub 1{rho}}) were measured for PDLCs as well as precursor mixtures based on the trifunctional monomer trimethylolpropane triacrylate (TMPTA) and the commercial nematic mixture E7. The variation of the main dipolar splitting of {sup 1}H spectra with increasing temperature was analyzed to obtain the nematic-to-isotropic phase transition temperature and the nematic order parameter of E7 and, for comparison, the nematic liquid crystal 5CB.Diffusion constants in TMPTA/E7 mixtures, measured by pulsed-field gradient NMR, increase for both E7 and TMPTA as the mass fraction of E7 increases, due to the lower viscosity of E7. E7 in the PDLC diffuses more slowly than in the bulk because of the hindrance by the polymer matrix. T{sub 1} and T{sub 1{rho}} relaxation times in the liquid or liquid-crystalline phases of TMPTA and bulk E7 are higher than in the PDLC and the pure polymer, due to the lower mobility in the polymer samples. T{sub 1{rho}} in the PDLC is even shorter than in the pure polymer, indicating an anti-softening effect caused by E7 molecules. In bulk E7, the well-ordered rod-like molecules exhibit a unique H-C dipolar coupling, which leads to oscillations in the cross-polarization curve. However, in the PDLC, the anchoring effect at the boundary between the polymer and LC droplets disturbs the molecular order resulting in a smooth cross polarization curve.

Investigation of a polymer-dispersed liquid crystal system by NMR diffusometry and relaxometry

International Nuclear Information System (INIS)

Tang, Mingxue

2013-01-01

Polymer-dispersed liquid crystals (PDLCs) are polymer composites containing a dispersion of liquid crystal droplets in polymer networks. PDLCs have attracted much attention due to their unique properties and potential usage. The properties of PDLCs depend on the degree of phase separation and the size of liquid crystal droplets. To investigate the structure will help us to better understand and optimize PDLCs.The main aim of this PhD thesis was to investigate PDLCs by NMR techniques. Diffusion constants and spin-lattice relaxation times in the laboratory (T 1 ) and rotating frame (T 1ρ ) were measured for PDLCs as well as precursor mixtures based on the trifunctional monomer trimethylolpropane triacrylate (TMPTA) and the commercial nematic mixture E7. The variation of the main dipolar splitting of 1 H spectra with increasing temperature was analyzed to obtain the nematic-to-isotropic phase transition temperature and the nematic order parameter of E7 and, for comparison, the nematic liquid crystal 5CB.Diffusion constants in TMPTA/E7 mixtures, measured by pulsed-field gradient NMR, increase for both E7 and TMPTA as the mass fraction of E7 increases, due to the lower viscosity of E7. E7 in the PDLC diffuses more slowly than in the bulk because of the hindrance by the polymer matrix. T 1 and T 1ρ relaxation times in the liquid or liquid-crystalline phases of TMPTA and bulk E7 are higher than in the PDLC and the pure polymer, due to the lower mobility in the polymer samples. T 1ρ in the PDLC is even shorter than in the pure polymer, indicating an anti-softening effect caused by E7 molecules. In bulk E7, the well-ordered rod-like molecules exhibit a unique H-C dipolar coupling, which leads to oscillations in the cross-polarization curve. However, in the PDLC, the anchoring effect at the boundary between the polymer and LC droplets disturbs the molecular order resulting in a smooth cross polarization curve.

Separation of technetium from nuclear waste stream simulants. Final report

International Nuclear Information System (INIS)

Strauss, S.H.

1995-01-01

The author studied liquid anion exchangers, such as Aliquat-336 nitrate, various pyridinium nitrates, and related salts, so that they may be applied toward a specific process for extracting (partitioning) and recovering 99 TcO 4 - from nuclear waste streams. Many of the waste streams are caustic and contain a variety of other ions. For this reason, the author studied waste stream simulants that are caustic and contain appropriate concentrations of selected, relevant ions. Methods of measuring the performance of the exchangers and extractant systems included contact experiments. Batch contact experiments were used to determine the forward and reverse extraction parameters as a function of temperature, contact time, phase ratio, concentration, solvent (diluent), and other physical properties. They were also used for stability and competition studies. Specifically, the author investigated the solvent extraction behavior of salts of perrhenate (ReO 4 - ), a stable (non-radioactive) chemical surrogate for 99 TcO 4 - . Results are discussed for alternate organic solvents; metalloporphyrins, ferrocenes, and N-cetyl pyridium nitrate as alternate extractant salts; electroactive polymers; and recovery of ReO 4 - and TcO 4 -

Rehabilitation of pure alexia

DEFF Research Database (Denmark)

Starrfelt, Randi; Ólafsdóttir, Rannveig Rós; Arendt, Ida-Marie

2013-01-01

that pure alexia was an easy target for rehabilitation efforts. We review the literature on rehabilitation of pure alexia from 1990 to the present, and find that patients differ widely on several dimensions like alexia severity, and associated deficits. Many patients reported to have pure alexia......-designed and controlled studies of rehabilitation of pure alexia....

Diffusion and solubility of oxygen in γ-ray irradiated polymer insulation materials

International Nuclear Information System (INIS)

Seguchi, Tadao; Yamamoto, Yasuaki.

1986-03-01

The effects of 60 Co γ-rays irradiation on diffusion and solubility of oxygen in polymer materials for electric cable insulation materials were investigated. The polymers were polyethylene, ethylene-propylene rubber, chlorinated polyethylene, chlorosulphonated polyethylene, and chloroprene rubber. They were pure grade and several types of formulation grade. The sheets of these polymers were irradiated up to 5 - 200 Mrad under vacuum or in oxygen under pressure of 3 - 15 atm at room temperature or at 70 deg C. By a method of gas desorption, the diffusion coefficient (D) and solubility coefficient (S) of oxygen or argon in polymer materials were determined at various temperatures of 10 - 80 deg C. The D and S decreased with increase of dose, and the decrease by irradiation with oxidation was more remarkable than that by irradiation without oxidation. However, the decreases of D and S by irradiation were reduced by the formulation of polymers. The additives in formulated polymers would reduce the reactions of crosslinking or oxidation by γ-ray irradiation. The activation energy of D was scarcely changed by irradiations with and without oxidation. (author)

Temporal coherence for pure tones in budgerigars (Melopsittacus undulatus) and humans (Homo sapiens).

Science.gov (United States)

Neilans, Erikson G; Dent, Micheal L

2015-02-01

Auditory scene analysis has been suggested as a universal process that exists across all animals. Relative to humans, however, little work has been devoted to how animals perceptually isolate different sound sources. Frequency separation of sounds is arguably the most common parameter studied in auditory streaming, but it is not the only factor contributing to how the auditory scene is perceived. Researchers have found that in humans, even at large frequency separations, synchronous tones are heard as a single auditory stream, whereas asynchronous tones with the same frequency separations are perceived as 2 distinct sounds. These findings demonstrate how both the timing and frequency separation of sounds are important for auditory scene analysis. It is unclear how animals, such as budgerigars (Melopsittacus undulatus), perceive synchronous and asynchronous sounds. In this study, budgerigars and humans (Homo sapiens) were tested on their perception of synchronous, asynchronous, and partially overlapping pure tones using the same psychophysical procedures. Species differences were found between budgerigars and humans in how partially overlapping sounds were perceived, with budgerigars more likely to segregate overlapping sounds and humans more apt to fuse the 2 sounds together. The results also illustrated that temporal cues are particularly important for stream segregation of overlapping sounds. Lastly, budgerigars were found to segregate partially overlapping sounds in a manner predicted by computational models of streaming, whereas humans were not. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Degradation of Polymers by Ultra-Violet Light

Energy Technology Data Exchange (ETDEWEB)

Turner, D. T. [Camille Dreyfus Laboratory, Research Triangle Institute, Research Triangle Park, NC (United States)

1968-10-15

To reach an understanding of the complex processes which occur when polymers are degraded by ultra-violet light under service conditions it is first judicious to try to elucidate the photochemistry of relatively simple polymer reactions. For this reason, emphasis is given to studies in which purified polymers, in bulk, were exposed to monochromatic radiations in the absence of oxygen. In respect of product analysis, emphasis is given to methods for estimating quantum yields for fractures and crosslinks. Photochemical mechanisms are illustrated by discussion of polystyrene, polytethylene terephthalate) and cellulose. Special emphasis is given to the role of free radicals. Attention is drawn to reports that the course of photolysis may be changed by application of an external pressure of a chemically inert gas, such as nitrogen. The explanation suggested in the literature is that this depends on the ease of escape of hydrogen atoms which, alternatively, might react with trapped polymer radicals. The course of photolysis may also be affected by polymer radicals acting as strongly absorbing chromophores and consequently undergoing further chemical reaction. This is illustrated by reference to the conversion of allyl radicals to alkyl radicals in polyethylene and also by changes observed in the ESR spectrum of polymer radicals trapped in poly (ethylene terephthalate) as a result of exposure to light. It is suggested that this effect is primarily responsible for the evolution of hydrocarbon gases on photolysis of polyethylene or natural rubber. In contrast, radiolysis of these polymers yields almost pure hydrogen because, in this case, energy is absorbed by relatively non-selective processes, i.e. free radicals do not absorb high energy radiation much more strongly than does their polymeric environment. (author)

Oil sands tailings treatment via surface modification of solids with polymers

Energy Technology Data Exchange (ETDEWEB)

Soane, D.; Ware, W.; Mahoney, R.; Kincaid, K. [Soane Energy, Cambridge, MA (United States)

2010-07-01

Oil sands fine tailings require large containment area and long-term storage. A recent directive has been established to reduce fluid tailings storage by 30 percent by 2012. This PowerPoint presentation described a method of treating oil sands tailings by modifying the surfaces of solids with polymers. The ATA process divided whole tailings into fines and coarse streams. The coarse stream was used to prepare anchor particles with a monolayer of tether polymers. An activator was added to the fine tailings in order to aggregate. The process cause a Velcro-like attraction between the activated fines and the tether-coated anchor particles. The solid ATA matrix trapped the fines and allowed water to drain more easily. Photographs of the process were provided. An analysis of the process demonstrated that 70 percent of the water in the tailings was recovered in less than 5 minutes. The water was clear, with less than 0.2 percent of suspended solids. The process is applicable to live tailings and mature fine tailings (MFT). tabs., figs.

Generation of Polymer Nanocomposites through Shear-Driven Aggregation of Binary Colloids

Directory of Open Access Journals (Sweden)

Xinxin Sheng

2017-11-01

Full Text Available Design of polymer nanocomposites has been an intense research topic in recent decades because hybrid nanomaterials are widely used in many fields. Throughout their development, there has often been a challenging issue how one can uniformly distribute nanoparticles (NPs in a polymer matrix, avoiding their agglomeration. In this short review, we first introduce the theory of colloidal aggregation/gelation purely based on intense shear forces. Then, we illustrate a methodology for preparing polymer nanocomposites where the NPs (as fillers are uniformly and randomly distributed inside a matrix of polymer NPs, based on intense shear-driven aggregation of binary colloids, without using any additives. Its feasibility has been demonstrated using two stable binary colloids composed of (1 poly-methyl methacrylate fillers and polystyrene NPs, and (2 graphene oxide sheets (fillers and poly-vinylidene fluoride NPs. The mechanism leading to capturing and distribution of the fillers inside the polymer NP matrix has been illustrated, and the advantages of the proposed methodology compared with the other common methods are also discussed.

Selective separation of Eu3+ using polymer-enhanced ultrafiltration

International Nuclear Information System (INIS)

Norton, M.V.

1994-03-01

A process to selectively remove 241 Am from liquid radioactive waste was investigated as an actinide separation method applicable to Hanford and other waste sites. The experimental procedures involved removal of Eu, a nonradioactive surrogate for Am, from aqueous solutions at pH 5 using organic polymers in conjunction with ultrafiltration. Commercially available polyacrylic acid (60,000 MW) and Pacific Northwest Laboratory's (PNL) synthesized E3 copolymer (∼10,000 MW) were tested. Test solutions containing 10 μg/mL of Eu were dosed vath each polymer at various concentrations in order to bind Eu (i.e., by complexation and/or cation exchange) for subsequent rejection by an ultrafiltration coupon. Test solutions were filtered with and without polymer to determine if enhanced Eu separation could be achieved from polymer treatment. Both polymers significantly increased Eu removal. Optimum concentrations were 20 μg/mL of polyacrylic acid and 100 μg/mL of E3 for 100% Eu rejection by the Amicon PM10 membrane at 55 psi. In addition to enhancement of removal, the polymers selectively bound Eu over Na, suggesting that selective separation of Eu was possible. This suggests that polymer-enhanced ultrafiltration is a potential process for separation of 241 Am from Hanford tank waste, further investigation of binding agents and membranes effective under very alkaline and high ionic strength is warranted. This process also has potential applications for selective separation of toxic metals from industrial process streams

Effect of organoclay on the orientation and thermal properties of liquid-crystalline polymers

CSIR Research Space (South Africa)

Bandyopadhyay, J

2007-08-01

Full Text Available in the pure LCP; in the nanocomposites, the polymer chains tended to orient in the direction of the dispersed clay layers. According to the DSC results, during first heating, the first melting peak represents the crystalline to nematic transition and, after...

Inhibition of surface crystallisation of amorphous indomethacin particles in physical drug-polymer mixtures

DEFF Research Database (Denmark)

Priemel, Petra A; Laitinen, Riikka; Barthold, Sarah

2013-01-01

stability than pure IMC whereas IMC Soluplus(®) mixtures did not. Water uptake was higher for mixtures containing Soluplus(®) than for amorphous IMC or IMC Eudragit(®) mixtures. However, the Tg of amorphous IMC was unaffected by the presence (and nature) of polymer. SEM revealed that Eudragit(®) particles...... through reduced IMC surface molecular mobility. Polymer particles may also mechanically hinder crystal growth outwards from the surface. This work highlights the importance of microparticulate surface coverage of amorphous drug particles on their stability....

Modification of polymer blends by irradiation

International Nuclear Information System (INIS)

Zuchowska, D.; Zagorski, Z.P.

1999-01-01

Modification of polymers, especially of polyolefin-elastomer blends (e. g. ethylene/propylene/diene terpolymer, ethylene propylene copolymer, ethylene/vinyl acetate copolymer etc.), by irradiation with a beam of fast electrons is discussed. Irradiation of polymer blends usually results in enhanced interactions between the constituents, caused among other things, by grafting induced at the polymer interphase. As a result, mechanical properties are affected to an extent depending on the proportion and type of constituent polymers, stabilizer content and radiation dose. Breaking strength (σ) relative elongation at break (ε) and melt flow rate (MFR), were examined for a triblock styrene/butadiene/styrene (SBS) copolymer, polypropylene (PP), and a PP-SBS blend (50:50 by wt.). In PP, the content of the crystal phase was determined. Irradiation was found to make SBS crosslink, as a result, σ rose by 25% and ε remained unaffected. PP was found to become degraded upon irradiation (MFR rose as much as 16 times), thereby σ and ε decreased considerably. In pure PP, the content of the crystal phase was found to increase. The variations of σ and ε in the irradiated PP-SBS blend follow a tendency similar to that in the SBS copolymer examined. This fact suggests the SBS copolymer to have a decisive effect on the macroscopic properties of the PP-SBS blend. (author)

Physical Aging, Plasticization and Their Effects on Gas Permeation in “Rigid” Polymers of Intrinsic Microporosity

KAUST Repository

Swaidan, Raja; Ghanem, Bader; Litwiller, Eric; Pinnau, Ingo

2015-01-01

Long-term physical aging and plasticization, two mobility-based phenomena that are counterintuitive in the context of “rigid” polymers of intrinsic microporosity (PIMs), were evaluated using pure- and mixed-gas permeation data for representative

Improved electrical properties of free standing blend polymer for renewable energy resources

Energy Technology Data Exchange (ETDEWEB)

Arya, Anil; Sharma, Sweety; Sharma, A. L., E-mail: alsharmaiitkgp@gmail.com [Centre for Physical Sciences, Central University of Punjab, Bathinda-151001 (India)

2016-05-23

Blend polymer electrolytes are prepared for salt concentration (Ö/Li = 4) with the constant ratio (0.5 gm) of PEO and PAN using solution casting technique. The prepared free standing solid polymeric film is characterized by Field Emission Scanning Electron Microscopy (FESEM) which confirms the homogeneous distribution of dissociated salt in blend polymer matrix. After addition of salt the ionic conductivity value is found to be of the order of 7.13 × 10{sup −5} Scm{sup −1} which is three orders higher when compared with pure blend polymer films. The microscopic interaction among the polymer-ion, ion-ion has been confirmed by the Fourier Transform Infrared (FTIR) Spectroscopy. A very fine correlation has been built in the electrical conductivity and FTIR result. On the basis of above finding, a prepared free standing solid polymeric film appears to be appropriate for the energy storage/conversion device applications.

Polymer sulfonation- a versatile route to prepare proton-conducting membrane material for advanced technologies

International Nuclear Information System (INIS)

Zaidi, S.M.J.

2003-01-01

Sulfonation of polymers is a viable method for making proton exchange membranes used in electrochemical devices. Polyether-ether ketone was modified by using concentrated sulfuric acid (97.4%) to produce ion-containing polymers bearing HSO3 groups. The sulfonated polymer was characterized for IEC, HNMR, DSC and water uptake etc. The degree of sulfonation of sulfonated PEEK was found to vary from 40 to 80 mol%. The PEEK became amorphous after sufonation (as evidenced from DSC and WXRD), which enhanced its solubility in organic solvents such as DMF. The glass transition temperature, Tg increased from 151C for pure PEEK to 217C upon sulfonation. The water uptake was also increased with sulfonation level, which provides formation of water-mediated pathways for protons involving SO3H groups. The membranes from these polymers have a high potential for use in electrochemical devices such as polymer fuel cell and electrodialysis. (author)

The Role of Electron Affinity in Determining Whether Fullerenes Catalyze or Inhibit Photooxidation of Polymers for Solar Cells

KAUST Repository

Hoke, Eric T.

2012-05-21

Understanding the stability and degradation mechanisms of organic solar materials is critically important to achieving long device lifetimes. Here, an investigation of the photodegradation of polymer:fullerene blend fi lms exposed to ambient conditions for a variety of polymer and fullerene derivative combinations is presented. Despite the wide range in polymer stabilities to photodegradation, the rate of irreversible polymer photobleaching in blend fi lms is found to consistently and dramatically increase with decreasing electron affi nity of the fullerene derivative. Furthermore, blends containing fullerenes with the smallest electron affi nities photobleached at a faster rate than fi lms of the pure polymer. These observations can be explained by a mechanism where both the polymer and fullerene donate photogenerated electrons to diatomic oxygen to form the superoxide radical anion which degrades the polymer. © 2012 WILEY-VCH Verlag GmbH & Co.

Unlocking Chain Exchange in Highly Amphiphilic Block Polymer Micellar Systems: Influence of Agitation.

Science.gov (United States)

Murphy, Ryan P; Kelley, Elizabeth G; Rogers, Simon A; Sullivan, Millicent O; Epps, Thomas H

2014-11-18

Chain exchange between block polymer micelles in highly selective solvents, such as water, is well-known to be arrested under quiescent conditions, yet this work demonstrates that simple agitation methods can induce rapid chain exchange in these solvents. Aqueous solutions containing either pure poly(butadiene- b -ethylene oxide) or pure poly(butadiene- b -ethylene oxide- d 4 ) micelles were combined and then subjected to agitation by vortex mixing, concentric cylinder Couette flow, or nitrogen gas sparging. Subsequently, the extent of chain exchange between micelles was quantified using small angle neutron scattering. Rapid vortex mixing induced chain exchange within minutes, as evidenced by a monotonic decrease in scattered intensity, whereas Couette flow and sparging did not lead to measurable chain exchange over the examined time scale of hours. The linear kinetics with respect to agitation time suggested a surface-limited exchange process at the air-water interface. These findings demonstrate the strong influence of processing conditions on block polymer solution assemblies.

A novel and facile strategy for highly flame retardant polymer foam composite materials: Transforming silicone resin coating into silica self-extinguishing layer.

Science.gov (United States)

Wu, Qian; Zhang, Qian; Zhao, Li; Li, Shi-Neng; Wu, Lian-Bin; Jiang, Jian-Xiong; Tang, Long-Cheng

2017-08-15

In this study, a novel strategy was developed to fabricate highly flame retardant polymer foam composite materials coated by synthesized silicone resin (SiR) polymer via a facile dip-coating processing. Applying the SiR polymer coating, the mechanical property and thermal stability of SiR-coated polymer foam (PSiR) composites are greatly enhanced without significantly altering their structure and morphology. The minimum oxygen concentration to support the combustion of foam materials is greatly increased, i.e. from LOI 14.6% for pure foam to LOI 26-29% for the PSiR composites studied. Especially, adjusting pendant group to SiOSi group ratio (R/Si ratio) of SiRs produces highly flame retardant PSiR composites with low smoke toxicity. Cone calorimetry results demonstrate that 44-68% reduction in the peak heat release rate for the PSiR composites containing different R/Si ratios over pure foam is achieved by the presence of appropriate SiR coating. Digital and SEM images of post-burn chars indicate that the SiR polymer coating can be transformed into silica self-extinguishing porous layer as effective inorganic barrier effect, thus preserving the polymer foam structure from fire. Our results show that the SiR dip-coating technique is a promising strategy for producing flame retardant polymer foam composite materials with improved mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymer-Assisted Hydrothermal Synthesis of Hierarchically Arranged Hydroxyapatite Nanoceramic

Directory of Open Access Journals (Sweden)

A. Joseph Nathanael

2013-01-01

Full Text Available Flower-like hydroxyapatite (HA nanostructures were synthesized by a polymer-assisted hydrothermal method. The thickness of the petals/plates decreased from 200 nm to 40 nm as the polymer concentration increased. The thickness also decreased as the hydrothermal treatment time increased from 6 to 12 hr. The HRTEM and SAED patterns suggest that the floral-like HA nanostructures are single crystalline in nature. Structural analysis based on XRD and Raman experiments implied that the produced nanostructure is a pure form of HA without any other impurities. The possible formation mechanism was discussed for the formation of flower-like HA nanostructures during polymer-assisted hydrothermal synthesis. Finally, in vitro cellular analysis revealed that the hierarchically arranged HA nanoceramic had improved cell viability relative to other structures. The cells were actively proliferated over these nanostructures due to lower cytotoxicity. Overall, the size and the crystallinity of the nanostructures played a role in improving the cell proliferation.

Evaluation of medium-chain-length polyhydroxyalkanoate production by Pseudomonas putida LS46 using biodiesel by-product streams.

Science.gov (United States)

Fu, Jilagamazhi; Sharma, Umesh; Sparling, Richard; Cicek, Nazim; Levin, David B

2014-07-01

Medium-chain-length polyhydroxyalkanoate (mcl-PHA) production by Pseudomonas putida LS46 was analyzed in shake-flask-based batch reactions, using pure chemical-grade glycerol (PG), biodiesel-derived "waste" glycerol (WG), and biodiesel-derived "waste" free fatty acids (WFA). Cell growth, substrate consumption, mcl-PHA accumulation within the cells, and the monomer composition of the synthesized biopolymers were monitored. The patterns of mcl-PHA synthesis in P. putida LS46 cells grown on PG and WG were similar but differed from that of cells grown with WFA. Polymer accumulation in glycerol-based cultures was stimulated by nitrogen limitation and plateaued after 48 h in both PG and WG cultures, with a total accumulation of 17.9% cell dry mass and 16.3% cell dry mass, respectively. In contrast, mcl-PHA synthesis was independent of nitrogen concentration in P. putida LS46 cells cultured with WFA, which accumulated to 29% cell dry mass. In all cases, the mcl-PHAs synthesized consisted primarily of 3-hydroxyoctanoate (C(8)) and 3-hydroxydecanoate (C(10)). WG and WFA supported similar or greater cell growth and mcl-PHA accumulation than PG under the experimental conditions used. These results suggest that biodiesel by-product streams could be used as low-cost carbon sources for sustainable mcl-PHA production.

Particle size dependence of the Young's modulus of filled polymers: 1. Preliminary experiments

NARCIS (Netherlands)

Vollenberg, P.H.T.; Heikens, D.

1989-01-01

Experimental results are reported from which it appears that in the case of polymer filled with silane-treated glass beads the Young's modulus is, in accordance with present theory, independent of the particle size of the filler. However, if pure glass beads are used as filler, the Young's modulus

Color Spectrum Properties of Pure and Non-Pure LATEX in Discriminating Rubber Clone Series

International Nuclear Information System (INIS)

Noor Aishah Khairuzzaman; Hadzli Hashim; Nina Korlina Madzhi; Noor Ezan Abdullah; Faridatul Aima Ismail; Ahmad Faiz Sampian; Azhana Fatnin Che Will

2015-01-01

A study of color spectrum properties for pure and non-pure latex in discriminating rubber clone series has been presented in this paper. There were five types of clones from the same series being used as samples in this study named RRIM2002, RRIM2007, RRIM2008, RRIM2014, and RRIM3001. The main objective is to identify the significant color spectrum (RGB) from pure and non-pure latex that can discriminate rubber clone series. The significant information of color spectrum properties for pure and non-pure latex is determined by using spectrometer and Statistical Package for the Social Science (SPSS). Visible light spectrum (VIS) is used as a radiation light of the spectrometer to emit light to the surface of the latex sample. By using SPSS software, the further numerical analysis of color spectrum properties is being conducted. As the conclusion, blue color spectrum for non-pure is able to discriminate for all rubber clone series whereas only certain color spectrum can differentiate several clone series for pure latex. (author)

Streaming potential investigations of polymer membranes developed for direct methanol fuel cell application

Czech Academy of Sciences Publication Activity Database

Richau, K.; Mohr, R.; Kůdela, Vlastimil; Schauer, Jan

2003-01-01

Roč. 14, - (2003), s. 201-204 ISSN 0915-860X. [International Conference on Ion Exchange. Kanazawa, 14.07.2003-18.07.2003] R&D Projects: GA MŠk ME 366 Institutional research plan: CEZ:AV0Z4050913 Keywords : streaming potential * ion-exchange membranes * specific conductivity Subject RIV: CG - Electrochemistry

Industrialization of polymer solar cells - phase 1

Energy Technology Data Exchange (ETDEWEB)

Lauritzen, H.; Krebs, F.C. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark); Andersen, Rasmus B. [Mekoprint A/S, Stoevrimg (Denmark); Bork, J.; Bentzen, B.

2012-03-15

A three-phased project with the objective to industrialize DTU's basic polymer solar cell technology was started in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project's phase 1.The key tasks in phase 1 are to stream-line DTU's tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level. The main focus in the stream-lining of DTU's technology has been to demonstrate a convincing rate of reduction for the production cost, and thereby make a competitive price plausible. This has been materialized as a learning curve showing that the polymer technology presently develops considerably faster than the silicon technology. The polymer solar cells will, under the assumption that both technologies follow a projection of the learning curve, gain a cost-leading position within a reasonable time. A production cost of 5 Euro/Wp has already been demonstrated in DTU's pilot plant, and a road map for the further decrease to 1 Euro/Wp is drawn. This target is expected to be reached in 2013 in the ongoing phase 2 of the project. Another activity essential for the industrialization has been the launch of specialized materials, equipment and services required for the processing of DTU's polymer solar cells. Relevant products and services are made available for sale on DTU's homepage, www.energyconversion.dtu.dk. A production line for polymer solar cells has been established at Mekoprint. For this a retrofit solution was chosen where the core of an existing screen-printing line was dismantled and fitted to a slot-die printing head manufactured in DTU's workshop

Phase behaviour of charged colloidal sphere dispersions with added polymer chains

International Nuclear Information System (INIS)

Fortini, Andrea; Dijkstra, Marjolein; Tuinier, Remco

2005-01-01

We study the stability of mixtures of highly screened repulsive charged spheres and non-adsorbing ideal polymer chains in a common solvent using free volume theory. The effective interaction between charged colloids in an aqueous salt solution is described by a screened Coulomb pair potential, which supplements the pure hard-sphere interaction. The ideal polymer chains are treated as spheres that are excluded from the colloids by a hard-core interaction, whereas the interaction between two ideal chains is set to zero. In addition, we investigate the phase behaviour of charged colloid-polymer mixtures in computer simulations, using the two-body (Asakura-Oosawa pair potential) approximation to the effective one-component Hamiltonian of the charged colloids. Both our results obtained from simulations and from free volume theory show similar trends. We find that the screened Coulomb repulsion counteracts the effect of the effective polymer-mediated attraction. For mixtures of small polymers and relatively large charged colloidal spheres, the fluid-crystal transition shifts to significantly larger polymer concentrations with increasing range of the screened Coulomb repulsion. For relatively large polymers, the effect of the screened Coulomb repulsion is weaker. The resulting fluid-fluid binodal is only slightly shifted towards larger polymer concentrations upon increasing the range of the screened Coulomb repulsion. In conclusion, our results show that the miscibility of dispersions containing charged colloids and neutral non-adsorbing polymers increases upon increasing the range of the screened Coulomb repulsion, or upon lowering the salt concentration, especially when the polymers are small compared to the colloids

Synthesis and characterization of an electrolyte system based on a biodegradable polymer

Directory of Open Access Journals (Sweden)

K. Sownthari

2013-06-01

Full Text Available A polymer electrolyte system has been developed using a biodegradable polymer namely poly-ε-caprolactone (PCL in combination with zinc triflate [Zn(CF3SO32] in different weight percentages and characterized during this investigation. Free-standing thin films of varying compositions were prepared by solution casting technique. The successful doping of the polymer has been confirmed by means of Fourier transform infrared spectroscopy (FTIR by analyzing the carbonyl (C=O stretching region of the polymer. The maximum ionic conductivity obtained at room temperature (25°C was found to be 8.8x10–6 S/cm in the case of PCL complexed with 25 wt% Zn(CF3SO32 which is five orders of magnitude higher than that of the pure polymer host material. The increase in amorphous phase with an increase in salt concentration of the prepared polymer electrolyte has also been confirmed from the concordant results obtained from X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopic (SEM analyses. Furthermore, the electrochemical stability window of the prepared polymer electrolyte was found to be 3.7 V. An electrochemical cell has been fabricated based on Zn/MnO2 electrode couple as an application area and its discharge characteristics were evaluated.

Separation of technetium from nuclear waste stream simulants. Final report

Energy Technology Data Exchange (ETDEWEB)

Strauss, S.H. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Chemistry

1995-09-11

The author studied liquid anion exchangers, such as Aliquat-336 nitrate, various pyridinium nitrates, and related salts, so that they may be applied toward a specific process for extracting (partitioning) and recovering {sup 99}TcO{sub 4}{sup {minus}} from nuclear waste streams. Many of the waste streams are caustic and contain a variety of other ions. For this reason, the author studied waste stream simulants that are caustic and contain appropriate concentrations of selected, relevant ions. Methods of measuring the performance of the exchangers and extractant systems included contact experiments. Batch contact experiments were used to determine the forward and reverse extraction parameters as a function of temperature, contact time, phase ratio, concentration, solvent (diluent), and other physical properties. They were also used for stability and competition studies. Specifically, the author investigated the solvent extraction behavior of salts of perrhenate (ReO{sub 4}{sup {minus}}), a stable (non-radioactive) chemical surrogate for {sup 99}TcO{sub 4}{sup {minus}}. Results are discussed for alternate organic solvents; metalloporphyrins, ferrocenes, and N-cetyl pyridium nitrate as alternate extractant salts; electroactive polymers; and recovery of ReO{sub 4}{sup {minus}} and TcO{sub 4}{sup {minus}}.

Analysis of feed stream acid gas concentration effects on the transport properties and separation performance of polymeric membranes for natural gas sweetening: A comparison between a glassy and rubbery polymer

KAUST Repository

Vaughn, Justin T.

2014-09-01

A 6FDA based polyamide-imide, 6F-PAI-1, is compared to Pebax®, a commercially available rubbery polyether/polyamide block copolymer, for the simultaneous separation of CO2 and H2S from CH4. Feed streams of 20/20/60 and 5/45/50H2S/CO2/CH4 were used to compare the effect of acid gas concentration on the separation efficiency of 6F-PAI-1 and Pebax® under industrially relevant conditions. 6F-PAI-1 showed CO2/CH4 selectivities at 850psia total feed pressure of 30 and 40 for the 20/20/60 and 5/45/50 feed streams, respectively, while selectivity for H2S/CH4 was approximately 20 for both feeds. Pebax® showed selectivities of 40 and 10 for H2S/CH4 and CO2/CH4, respectively. Both selectivities were mostly independent of acid gas concentration in the feed, an unsurprising trend considering the non-glassy nature of this material. The selectivities in 6F-PAI-1 translated to less than 6% CH4 lost in the permeate stream for both feeds, while for the 5/45/50 feed, CH4 fraction in the permeate at 850psia was less than 4%. These promising results suggest that glassy polymers possessing favorable intrinsic plasticization resistance, such as 6F-PAI-1, may be appropriate for the typical case of natural gas sweetening where CO2 concentration in the feed is higher than it is for H2S. © 2014 Elsevier B.V.

Efficient Homodifunctional Bimolecular Ring-Closure Method for Cyclic Polymers by Combining RAFT and Self-Accelerating Click Reaction.

Science.gov (United States)

Qu, Lin; Sun, Peng; Wu, Ying; Zhang, Ke; Liu, Zhengping

2017-08-01

An efficient metal-free homodifunctional bimolecular ring-closure method is developed for the formation of cyclic polymers by combining reversible addition-fragmentation chain transfer (RAFT) polymerization and self-accelerating click reaction. In this approach, α,ω-homodifunctional linear polymers with azide terminals are prepared by RAFT polymerization and postmodification of polymer chain end groups. By virtue of sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA) as small linkers, well-defined cyclic polymers are then prepared using the self-accelerating double strain-promoted azide-alkyne click (DSPAAC) reaction to ring-close the azide end-functionalized homodifunctional linear polymer precursors. Due to the self-accelerating property of DSPAAC ring-closing reaction, this novel method eliminates the requirement of equimolar amounts of telechelic polymers and small linkers in traditional bimolecular ring-closure methods. It facilitates this method to efficiently and conveniently produce varied pure cyclic polymers by employing an excess molar amount of DBA small linkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Surface Roughness on Polymer Drag Reduction with a High-Reynolds-Number Turbulent Boundary Layer

Science.gov (United States)

Elbing, Brian; Dowling, David; Solomon, Michael; Bian, Sherry; Ceccio, Steven

2007-11-01

A recent experiment at the U.S. Navy's Large Cavitation Channel (LCC) investigated the effect of wall roughness on wall-injection polymer drag reduction (PDR) within a high-Reynolds-number (10^7 to 2x10^8 based on downstream distance) turbulent boundary layer (TBL). Testing was performed in two parts: 1) PDR experiment on a 12.9 m long, 3.05 m wide hydro-dynamically smooth flat plate and 2) PDR experiment on the same model with the entire surface roughened. The roughness was produced by blowing glass beads into epoxy paint that was applied to the entire model. The roughened model had an average roughness height ranging between 307 and 1154 μm. Drag reduction was determined using six, stream-wise located integrated skin-friction balances. In addition to skin-friction measurements, sampling was performed at three stream-wise located ports. The sampling ports were used to determine the amount of degradation, if any, caused by the turbulent flow on the polymer. Both the skin-friction measurements and sampling analysis indicates that wall roughness in a turbulent boundary layer significantly increases degradation of the polymer solution.

Antibacterial Properties of Silver-Loaded Plasma Polymer Coatings

International Nuclear Information System (INIS)

Ploux, L.; Mateescu, M.; Anselme, K.; Vasilev, K.

2012-01-01

In a previous paper, we proposed new silver nanoparticles (SNPs) based antibacterial coatings able to protect eukaryotic cells from SNPs related toxic effects, while preserving antibacterial efficiency. A SNPs containing n-heptylamine (HA) polymer matrix was deposited by plasma polymerization and coated by a second HA layer. In this paper, we elucidate the antibacterial action of these new coatings. We demonstrated that SNPs-loaded material can be covered by thin HA polymer layer without losing the antibacterial activity to planktonic bacteria living in the near surroundings of the material. SNPs-containing materials also revealed antibacterial effect on adhered bacteria. Adhered bacteria number was significantly reduced compared to pure HA plasma polymer and the physiology of the bacteria was affected. The number of adhered bacteria directly decreased with thickness of the second HA layer. Surprisingly, the quantity of cultivable bacteria harvested by transfer to nutritive agar decreased not only with the presence of SNPs, but also in relation to the covering HA layer thickness, that is, oppositely to the increase in adhered bacteria number. Two hypotheses are proposed for this surprising result (stronger attachment or weaker vitality), which raises the question of the diverse potential ways of action of SNPs entrapped in a polymer matrix.

Sixth form pure mathematics

CERN Document Server

Plumpton, C

1968-01-01

Sixth Form Pure Mathematics, Volume 1, Second Edition, is the first of a series of volumes on Pure Mathematics and Theoretical Mechanics for Sixth Form students whose aim is entrance into British and Commonwealth Universities or Technical Colleges. A knowledge of Pure Mathematics up to G.C.E. O-level is assumed and the subject is developed by a concentric treatment in which each new topic is used to illustrate ideas already treated. The major topics of Algebra, Calculus, Coordinate Geometry, and Trigonometry are developed together. This volume covers most of the Pure Mathematics required for t

Flow of a stream through a reservoir

International Nuclear Information System (INIS)

Sauerwein, K.

1967-01-01

If a reservoir is fed from a single source, which may not always be pure, the extent to which the inflowing stream mixes with the water in the reservoir is important for the quality of the water supplied by the reservoir. This question was investigated at the Lingese Reservoir, containing between one and two million cubic metres of water, in the Bergisches Land (North Rhine-Westphalia). The investigation was carried out at four different seasons so that the varying effects of the stream-water temperatures could be studied in relation to the temperature of the reservoir water. The stream was radioactively labelled at the point of inflow into the reservoir, and its flow through the reservoir was measured in length and depth from boats, by means of 1-m-long Geiger counters. In two cases the radioactivity of the outflowing water was also measured at fixed points. A considerable variety of intermixing phenomena were observed; these were mainly of limnological interest. The results of four experiments corresponding to the four different seasons are described in detail. They were as follows: (1) The mid-October experiment where the stream, with a temperature of 8.0 deg. C, was a good 5 deg. C colder than the water of the reservoir, whose temperature was almost uniform, ranging from 13.2 deg. C at the bed to 13.6 deg. C at the surface. (2) The spring experiment (second half of March), when the stream temperature was only 0.3 deg. C below that of the reservoir surface (7.8 deg. C), while the temperature of the bed was 5.8 deg. C. (3) The winter experiment (early December) where at first the temperature of the stream was approximately the same as that of the surface so that, once again, the stream at first flowed 1/2 - 1 m below the surface. During the almost wind-free night a sudden fall in temperature occurred, and the air temperature dropped from 0 deg. C to -12 deg. C. (4) The summer experiment (end of July to mid-August) when the stream was nearly 1 deg. C colder than

A combined chemical + enzymatic method to remove selected aromatics from aqueous streams

International Nuclear Information System (INIS)

Xu, X.; John, V.

1993-01-01

Aromatics are major pollutants found in aqueous environments and in sediments. While there are many chemical and biochemical processes to remove and/or destroy these contaminants, they have to be considered in light of the economics and the time-scales for treatment. We describe our initial work on a hybrid chemical + enzymatic technique to remove aromatics from aqueous stream. The aromatic is first converted to the corresponding phenol through classical Fenton type chemistry involving catalysis by Fe(II). The phenol is subsequently polymerized through an enzymatic mechanism, using horseradish peroxidase as the oxidative enzyme. The polymer is insoluble in water and can be easily recovered. In addition, such phenolic polymers are useful products with varied applications in coatings and resin technologies. Thus, the pollutants can be eventually converted to useful products

USE OF RECYCLED POLYMERS FOR ENCAPSULATION OF RADIOACTIVE, HAZARDOUS AND MIXED WASTES

International Nuclear Information System (INIS)

LAGERRAAEN, P.R.; KALB, P.D.

1997-01-01

Polyethylene encapsulation is a waste treatment technology developed at Brookhaven National Laboratory using thermoplastic polymers to safely and effectively solidify hazardous, radioactive and mixed wastes for disposal. Over 13 years of development and demonstration with surrogate wastes as well as actual waste streams on both bench and full scale have shown this to be a viable and robust technology with wide application. Process development efforts have previously focused on the use of virgin polymer feedstocks. In order to potentially improve process economics and serve to lessen the municipal waste burden, recycled polymers were investigated for use as encapsulating agents. Recycled plastics included low-density polyethylene, linear low-density polyethylene, high-density polyethylene and polypropylene, and were used as a direct substitute for or blended together with virgin resin. Impacts on processing and final waste form performance were examined

Non-critical pure spinor superstrings

International Nuclear Information System (INIS)

Adam, Ido; Grassi, Pietro Antonio; Mazzucato, Luca; Oz, Yaron; Yankielowicz, Shimon

2007-01-01

We construct non-critical pure spinor superstrings in two, four and six dimensions. We find explicitly the map between the RNS variables and the pure spinor ones in the linear dilaton background. The RNS variables map onto a patch of the pure spinor space and the holomorphic top form on the pure spinor space is an essential ingredient of the mapping. A basic feature of the map is the requirement of doubling the superspace, which we analyze in detail. We study the structure of the non-critical pure spinor space, which is different from the ten-dimensional one, and its quantum anomalies. We compute the pure spinor lowest lying BRST cohomology and find an agreement with the RNS spectra. The analysis is generalized to curved backgrounds and we construct as an example the non-critical pure spinor type IIA superstring on AdS 4 with RR 4-form flux

Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

Energy Technology Data Exchange (ETDEWEB)

Swain, Basudev, E-mail: swain@iae.re.kr [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Mishra, Chinmayee [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Hong, Hyun Seon [Sungshin University, Dept. of Interdisciplinary ECO Science, Seoul, 142-732 (Korea, Republic of); Cho, Sung-Soo [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of)

2016-05-15

Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m{sup 3} of copper and 1.35 kg/m{sup 3} of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching

Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

International Nuclear Information System (INIS)

Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

2016-01-01

Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m 3 of copper and 1.35 kg/m 3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching wastewater

Weighted density approximation for bonding in molecules: ring and cage polymers

CERN Document Server

Sweatman, M B

2003-01-01

The focus of this work is the bonded contribution to the intrinsic Helmholtz free energy of molecules. A weighted density approximation (WDA) for this contribution is presented within the interaction site model (ISM) for ring and cage polymers. The resulting density functional theory (ISM/WDA) for these systems is no more complex than theories for a pure simple fluid, and much less complex than density functional approaches that treat the bonding functional exactly. The ISM/WDA bonding functional is much more accurate than either the ISM/HNC or ISM/PY bonding functionals, which are related to the reference interaction-site model (RISM)/HNC and RISM/PY integral equations respectively, for ideal ring polymers. This means that the ISM/WDA functional should generally be more accurate for most 'real' ring or cage polymer systems when any reasonable approximation for the 'excess' contribution to the intrinsic Helmholtz free energy is employed.

Weighted density approximation for bonding in molecules: ring and cage polymers

International Nuclear Information System (INIS)

Sweatman, M B

2003-01-01

The focus of this work is the bonded contribution to the intrinsic Helmholtz free energy of molecules. A weighted density approximation (WDA) for this contribution is presented within the interaction site model (ISM) for ring and cage polymers. The resulting density functional theory (ISM/WDA) for these systems is no more complex than theories for a pure simple fluid, and much less complex than density functional approaches that treat the bonding functional exactly. The ISM/WDA bonding functional is much more accurate than either the ISM/HNC or ISM/PY bonding functionals, which are related to the reference interaction-site model (RISM)/HNC and RISM/PY integral equations respectively, for ideal ring polymers. This means that the ISM/WDA functional should generally be more accurate for most 'real' ring or cage polymer systems when any reasonable approximation for the 'excess' contribution to the intrinsic Helmholtz free energy is employed

Enzymatic synthesis of lignin-siloxane hybrid functional polymers.

Science.gov (United States)

Prasetyo, Endry Nugroho; Kudanga, Tukayi; Fischer, Roman; Eichinger, Reinhard; Nyanhongo, Gibson S; Guebitz, Georg M

2012-02-01

This study combines the properties of siloxanes and lignin polymers to produce hybrid functional polymers that can be used as adhesives, coating materials, and/or multifunctionalized thin-coating films. Lignin-silica hybrid copolymers were synthesized by using a sol-gel process. Laccases from Trametes hirsuta were used to oxidize lignosulphonates to enhance their reactivity towards siloxanes and then were incorporated into siloxane precursors undergoing a sol-gel process. In vitro copolymerization studies using pure lignin monomers with aminosilanes or ethoxytrimethylsilane and analysis by ²⁹Si NMR spectroscopy revealed hybrid products. Except for kraft lignin, an increase in lignin concentration positively affected the tensile strength in all samples. Similarly, the viscosity generally increased in all samples with increasing lignin concentration and also affected the curing time. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and Rheological Properties of an Associative Star Polymer in Aqueous Solutions

DEFF Research Database (Denmark)

Hietala, Sami; Mononen, Pekka; Strandman, Satu

2007-01-01

synthesised by atom transfer radical. polymerization (ATRP) was found to fonn hydrogels at room temperature at polymer concentrations. Cp, over 22 gIL due to the interpolymer drophobic association of the PS blocks. Increasing Cp leads to stronger elastic networks at room temperature that show a gel......Rheological properties of aqueous solutions and hydrogels fonned by an amphiphiIic star block copolymer poly(acrylic acid)-blockpolystyrene (PAAS4-b-PS6)4. were investigated as a function of the polymer concentration (Cp), temperature, and added saIt concentration. The water-soluble polymer......-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling Cp, which...

Adsorbed polymers in aqueous media. The relation between zeta-potential, layer thickness and ionic strength

NARCIS (Netherlands)

Cohen Stuart, M.A.; Mulder, J.W.

1985-01-01

Streaming potentials for glass capillaries with and without adsorbed poly(vinyl pyrrolidone) were used to determine the thickness of the adsorbed polymer layer. It was found that the thickness determined in this way is a strong function of the ionic strength of the solution. The results are compared

Advanced Proton Conducting Polymer Electrolytes for Electrochemical Capacitors

Science.gov (United States)

Gao, Han

. The optimized polymer electrolyte demonstrated even higher proton conductivity than pure HPAs and the enabled electrochemical capacitors have demonstrated an exceptionally high rate capability of 50 Vs-1 in cyclic voltammograms and a 10 ms time constant in impedance analyses.

A preliminary assessment of polymer-modified cements for use in immobilisation of intermediate level radioactive waste

International Nuclear Information System (INIS)

Burnay, S.G.; Dyson, J.R.

1982-11-01

A range of polymer-modified cements has been examined as candidate materials for the immobilisation of intermediate level radioactive waste. The waste streams studied were inactive simulates of real wastes and included ion-exchange resins, Magnox debris and dilute sludges. Preliminary experiments on the compatibility of the polymer-cement-waste combinations have been carried out and measurements of flexural strength before and after #betta#-irradiation to 10 9 rad and water immersion have been made. Soxhlet leach tests have been used to compare the leach rates of the different materials. From the results of these preliminary experiments, a limited number of polymer-modified cements have been suggested as suitable for more detailed study. (author)

Relation between exciplex formation and photovoltaic properties of PPV polymer-based blends

Energy Technology Data Exchange (ETDEWEB)

Yin, Chunhong; Neher, Dieter [Institute of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam (Germany); Kietzke, Thomas [Institute of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam (Germany); Institute of Materials Research and Engineering (IMRE), Research Link 3, 117602 Singapore (Singapore); Kumke, Michael [Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Street 24-25, 14476 Golm (Germany); Hoerhold, Hans-Heinrich [Institute of Organic Chemistry and Macromolecular Chemistry, University of Jena, Humboldtstr. 10, 07743 Jena (Germany)

2007-03-06

As a new record for pure polymer-blend solar cells, an energy conversion efficiency (ECE) of 1.7% was recently achieved for M3EH-PPV:CN-ether-PPV (Poly[oxa-1,4-phenylene-1,2-(1-cyano)-ethylene-2,5-dioctyloxy-1,4-phenylene-1,2- (2-cyano)-ethylene-1,4-phenylene]) based devices [T. Kietzke, H.-H. Hoerhold, D. Neher, Chem. Mater. 17 (2005) 6532]. Even though that photoluminescence experiments indicated that 95% of the photogenerated excitions were dissociated in the blend, the external quantum efficiency reached only 31%. Thus more than 2/3 of the dissociated excitons were lost for the energy conversion. In order to identify the processes which limit the photovoltaic efficiency of polymer-blend solar cells, studies on the steady state and time-resolved photoluminescence of the individual polymer and polymer blend were performed. In the polymer-blend layer, we observed a considerable long-wavelength emission due to exciplex formation. The exciplex emission can be reduced by thermal annealing. At the same time the IPCE of the blend-based device increased, indicating a more efficient generation of free-charge carriers. These findings lead to the conclusion that charge-carrier recombination via exciplex formation constitutes one of the loss channels which limits the efficiency of polymer solar cells. (author)

Toxicity evaluation of the process effluent streams of a petrochemical industry.

Science.gov (United States)

Reis, J L R; Dezotti, M; Sant'Anna, G L

2007-02-01

The physico-chemical characteristics and the acute toxicity of several wastewater streams, generated in the industrial production of synthetic rubber, were determined. The acute toxicity was evaluated in bioassays using different organisms: Danio rerio (fish), Lactuca sativa (lettuce) and Brachionus calyciflorus (rotifer). The removal of toxicity attained in the industrial wastewater treatment plant was also determined upstream and downstream of the activated sludge process. The results obtained indicate that the critical streams in terms of acute toxicity are the effluents from the liquid polymer unit and the spent caustic butadiene washing stage. The biological treatment was able to partially remove the toxicity of the industrial wastewater. However, a residual toxicity level persisted in the biotreated wastewater. The results obtained with Lactuca sativa showed a high degree of reproducibility, using root length or germination index as evaluation parameters. The effect of volatile pollutants on the toxicity results obtained with lettuce seeds was assessed, using ethanol as a model compound. Modifications on the assay procedure were proposed. A strong correlation between the toxic responses of Lactuca sativa and Danio rerio was observed for most industrial effluent streams.

The Stream-Catchment (StreamCat) and Lake-Catchment ...

Science.gov (United States)

Background/Question/MethodsLake and stream conditions respond to both natural and human-related landscape features. Characterizing these features within contributing areas (i.e., delineated watersheds) of streams and lakes could improve our understanding of how biological conditions vary spatially and improve the use, management, and restoration of these aquatic resources. However, the specialized geospatial techniques required to define and characterize stream and lake watersheds has limited their widespread use in both scientific and management efforts at large spatial scales. We developed the StreamCat and LakeCat Datasets to model, predict, and map the probable biological conditions of streams and lakes across the conterminous US (CONUS). Both StreamCat and LakeCat contain watershed-level characterizations of several hundred natural (e.g., soils, geology, climate, and land cover) and anthropogenic (e.g., urbanization, agriculture, mining, and forest management) landscape features for ca. 2.6 million stream segments and 376,000 lakes across the CONUS, respectively. These datasets can be paired with field samples to provide independent variables for modeling and other analyses. We paired 1,380 stream and 1,073 lake samples from the USEPAs National Aquatic Resource Surveys with StreamCat and LakeCat and used random forest (RF) to model and then map an invertebrate condition index and chlorophyll a concentration, respectively. Results/ConclusionsThe invertebrate

Preparation of nanocrystalline iron-carbon materials as fillers for polymers

International Nuclear Information System (INIS)

Narkiewicz, U; Pelech, I; Roslaniec, Z; Kwiatkowska, M; Arabczyk, W

2007-01-01

This paper presents a method of preparing nanocrystalline iron-carbon materials which can be applied as fillers for polymers. Nanocrystalline iron samples were carburized either under ethylene/hydrogen mixture or under pure ethylene. Three kinds of samples were prepared: cementite/carbon (Fe 3 C/C), iron/cementite (Fe/Fe 3 C) and iron/carbon (Fe/C) ones. After carburization the samples were characterized using XRD and SEM methods. The obtained samples of iron-carbon nanoparticles were applied as fillers to polymer nanocomposites prepared in a polycondensation reaction (in situ) in a poly(ether-ester) matrix. The nanofillers were dispersed in monomers (diols) using a sonificator and a high-speed rotary stirrer. The obtained nanocomposites were characterized as regards their structure (SEM method) and mechanical behaviour

Auditory Streaming as an Online Classification Process with Evidence Accumulation

Science.gov (United States)

Barniv, Dana; Nelken, Israel

2015-01-01

When human subjects hear a sequence of two alternating pure tones, they often perceive it in one of two ways: as one integrated sequence (a single "stream" consisting of the two tones), or as two segregated sequences, one sequence of low tones perceived separately from another sequence of high tones (two "streams"). Perception of this stimulus is thus bistable. Moreover, subjects report on-going switching between the two percepts: unless the frequency separation is large, initial perception tends to be of integration, followed by toggling between integration and segregation phases. The process of stream formation is loosely named “auditory streaming”. Auditory streaming is believed to be a manifestation of human ability to analyze an auditory scene, i.e. to attribute portions of the incoming sound sequence to distinct sound generating entities. Previous studies suggested that the durations of the successive integration and segregation phases are statistically independent. This independence plays an important role in current models of bistability. Contrary to this, we show here, by analyzing a large set of data, that subsequent phase durations are positively correlated. To account together for bistability and positive correlation between subsequent durations, we suggest that streaming is a consequence of an evidence accumulation process. Evidence for segregation is accumulated during the integration phase and vice versa; a switch to the opposite percept occurs stochastically based on this evidence. During a long phase, a large amount of evidence for the opposite percept is accumulated, resulting in a long subsequent phase. In contrast, a short phase is followed by another short phase. We implement these concepts using a probabilistic model that shows both bistability and correlations similar to those observed experimentally. PMID:26671774

Love Wave Sensor for Prostate-Specific Membrane Antigen Detection Based on Hydrophilic Molecularly-Imprinted Polymer

Directory of Open Access Journals (Sweden)

Pingping Tang

2018-05-01

Full Text Available Prostate-specific membrane antigen (PSMA is a biomarker for prostate cancer (PCa, and a specific and reliable detection technique of PSMA is urgently required for PCa early diagnosis. A Love wave sensor has been widely studied for real-time sensing and highly sensitive applications, but the sensing unit needs special handling for selective detection purpose. In this study, we prepared a versatile Love wave sensor functionalized with molecularly-imprinted polymers (MIP, PSMA as the template molecule. To enhance the specific template bindings of MIP in pure aqueous solutions, facile reversible addition/fragmentation chain transfer (RAFT precipitation polymerization (RAFTPP was used to produce surface hydrophilic polymer brushes on MIP. The presence of hydrophilic polymer brushes on MIP improved its surface hydrophilicity and significantly reduced their hydrophobic interactions with template molecules in pure aqueous media. In detection process, the acoustic delay-line is confederative to a microfluidic chip and inserted in an oscillation loop. The real-time resonance frequency of the MIP-based Love wave sensor to different concentrations of PSMA was investigated. The limit of detection (LOD for this Love SAW sensor was 0.013 ng mL−1, which demonstrates that this sensor has outstanding performance in terms of the level of detection.

Nanostructured Block Polymer Membranes as High Capacity Adsorbers for the Capture of Metal Ions from Water

Science.gov (United States)

Boudouris, Bryan; Weidman, Jacob; Mulvenna, Ryan; Phillip, William

The efficient removal of metal ions from aqueous streams is of significant import in applications ranging from industrial waste treatment to the purification of drinking water. An emerging paradigm associated with this separation is one that utilizes membrane adsorbers as a means by which to bind metal salt contaminants. Here, we demonstrate that the casting of an A-B-C triblock polymer using the self-assembly and non-solvent induced phase separation (SNIPS) methodology results in a nanoporous membrane geometry. The nature of the triblock polymer affords an extremely high density of binding sites within the membrane. As such, we demonstrate that the membranes with binding capacities equal to that of state-of-the-art packed bed columns. Moreover, because the affinity of the C moiety can be tuned, highly selective binding events can occur based solely on the chemistry of the block polymer and the metal ions in solution (i.e., in a manner that is independent of the size of the metal ions). Due to these combined facts, these membranes efficiently remove heavy metal (e.g., lead- and cadmium-based) salts from contaminated water streams with greater than 95% efficiency. Finally, we show that the membranes can be regenerated through a simple treatment in order to provide long-lasting adsorber systems as well. Thus, it is anticipated that these nanostructured triblock polymer membranes are a platform by which to obtain next-generation water purification processes.

Preparation and characterization of very pure zirconium tetrafluoride. Application to fluorinated glass

International Nuclear Information System (INIS)

Bridenne, M.

1986-12-01

The synthesis of anhydrous and very pure zirconium tetrafluoride from zirconium tetraborohydride is studied. Zr F 4 is used for fabrication of fluorozirconate glass. Zr (BH 4 ) 4 is purified by sublimation. Two fluorinating agents F 2 and anhydrous HF are used for fluorination. The apparatus is made of fluorinated polymers and a Kel-F prototype reactor was realized. 20 g of Zr F 4 are obtained in 44 hrs with a yield of 88 %. Purity is characterized by chemical analysis (atomique absorption spectroscopy and spark mass spectroscopy) and absorption of an optical fiber made of zirconium tetrafluoride. Cr, Ni, Co and Cu content is lower than 0.1 ppm. Possibility of pilot scale production is discussed [fr

Streaming Pool: reuse, combine and create reactive streams with pleasure

CERN Multimedia

CERN. Geneva

2017-01-01

When connecting together heterogeneous and complex systems, it is not easy to exchange data between components. Streams of data are successfully used in industry in order to overcome this problem, especially in the case of "live" data. Streams are a specialization of the Observer design pattern and they provide asynchronous and non-blocking data flow. The ongoing effort of the ReactiveX initiative is one example that demonstrates how demanding this technology is even for big companies. Bridging the discrepancies of different technologies with common interfaces is already done by the Reactive Streams initiative and, in the JVM world, via reactive-streams-jvm interfaces. Streaming Pool is a framework for providing and discovering reactive streams. Through the mechanism of dependency injection provided by the Spring Framework, Streaming Pool provides a so called Discovery Service. This object can discover and chain streams of data that are technologically agnostic, through the use of Stream IDs. The stream to ...

Pec power generation system using pure energy

Energy Technology Data Exchange (ETDEWEB)

Tanaka, K; Sonai, A; Kano, A [Toshiba International Fuel Cells Corp. (Japan). Cell Technology Development Dept.; Yatake, T [Toshiba International Fuel Cells Corp. (Japan). Plant Engineering Dept.

2002-07-01

A polymer electrolyte fuel cell (PEFC) power generation system using pure hydrogen was developed by Toshiba International Fuel Cells (TIFC), Japan, under the sponsorship of the World Energy Network (WE-NET) Project. The goals of the project consist of the construction of 30 kilowatt power generation plant for stationary application and target electrical efficiency of over 50 per cent. Two critical technologies were investigated for high utilization stack, as high hydrogen utilization operation represents one of the most important items for the achievement of target efficiency. The first technology examined was the humidification method from cathode side, while the second was the two-block configuration, which is arranged in series in accordance with the flow of hydrogen. Using these technologies as a basis for the work, a 5 kilowatt short stack was developed, and a steady performance was obtained under high hydrogen utilization of up to 98 per cent. It is expected that by March 2003 the design of the hydrogen fueled 30 kilowatt power generation plant will be completed and assembled. 1 ref., 1 tab., 11 figs.

Metal Oxide Nanoparticles in Electrospun Polymers and Their Fate in Aqueous Waste Streams

Science.gov (United States)

Hoogesteijn von Reitzenstein, Natalia

Nanotechnology is becoming increasingly present in our environment. Engineered nanoparticles (ENPs), defined as objects that measure less than 100 nanometers in at least one dimension, are being integrated into commercial products because of their small size, increased surface area, and quantum effects. These special properties have made ENPs antimicrobial agents in clothing and plastics, among other applications in industries such as pharmaceuticals, renewable energy, and prosthetics. This thesis incorporates investigations into both application of nanoparticles into polymers as well as implications of nanoparticle release into the environment. First, the integration of ENPs into polymer fibers via electrospinning was explored. Electrospinning uses an external electric field applied to a polymer solution to produce continuous fibers with large surface area and small volume, a quality which makes the fibers ideal for water and air purification purposes. Indium oxide and titanium dioxide nanoparticles were embedded in polyvinylpyrrolidone and polystyrene. Viscosity, critical voltage, and diameter of electrospun fibers were analyzed in order to determine the effects of nanoparticle integration into the polymers. Critical voltage and viscosity of solution increased at 5 wt% ENP concentration. Fiber morphology was not found to change significantly as a direct effect of ENP addition, but as an effect of increased viscosity and surface tension. These results indicate the possibility for seamless integration of ENPs into electrospun polymers. Implications of ENP release were investigated using phase distribution functional assays of nanoscale silver and silver sulfide, as well as photolysis experiments of nanoscale titanium dioxide to quantify hydroxyl radical production. Functional assays are a means of screening the relevant importance of multiple processes in the environmental fate and transport of ENPs. Four functional assays---water-soil, water-octanol, water

Interaction between stream temperature, streamflow, and groundwater exchanges in alpine streams

Science.gov (United States)

Constantz, James E.

1998-01-01

Four alpine streams were monitored to continuously collect stream temperature and streamflow for periods ranging from a week to a year. In a small stream in the Colorado Rockies, diurnal variations in both stream temperature and streamflow were significantly greater in losing reaches than in gaining reaches, with minimum streamflow losses occurring early in the day and maximum losses occurring early in the evening. Using measured stream temperature changes, diurnal streambed infiltration rates were predicted to increase as much as 35% during the day (based on a heat and water transport groundwater model), while the measured increase in streamflow loss was 40%. For two large streams in the Sierra Nevada Mountains, annual stream temperature variations ranged from 0° to 25°C. In summer months, diurnal stream temperature variations were 30–40% of annual stream temperature variations, owing to reduced streamflows and increased atmospheric heating. Previous reports document that one Sierra stream site generally gains groundwater during low flows, while the second Sierra stream site may lose water during low flows. For August the diurnal streamflow variation was 11% at the gaining stream site and 30% at the losing stream site. On the basis of measured diurnal stream temperature variations, streambed infiltration rates were predicted to vary diurnally as much as 20% at the losing stream site. Analysis of results suggests that evapotranspiration losses determined diurnal streamflow variations in the gaining reaches, while in the losing reaches, evapotranspiration losses were compounded by diurnal variations in streambed infiltration. Diurnal variations in stream temperature were reduced in the gaining reaches as a result of discharging groundwater of relatively constant temperature. For the Sierra sites, comparison of results with those from a small tributary demonstrated that stream temperature patterns were useful in delineating discharges of bank storage following

Novel synthesis of Eu-doped SiAlON luminescent materials from a preceramic polymer and nano-sized fillers

Directory of Open Access Journals (Sweden)

E. Bernardo

2014-06-01

The reduction of Eu3+ into Eu2+ incorporated in SiAlON was favored by the presence of carbon derived from the pyrolysis of the preceramic polymers. The nanometric distribution of filler materials and the high yield of the selected preceramic polymers in terms of Si and N atoms led to the formation of the desired phases at relatively low firing temperatures (e.g. 3 h at 1550–1600 °C in pure nitrogen.

Fabrication of a PANI/CPs composite material: a feasible method to enhance the photocatalytic activity of coordination polymers.

Science.gov (United States)

Xu, Xin-Xin; Cui, Zhong-Ping; Qi, Ji; Liu, Xiao-Xia

2013-03-21

To improve the photocatalytic activity of a coordination polymer in the visible light region, polyaniline (PANI) was loaded onto its surface through a facile in situ chemical oxidation polymerization process. The resulting PANI loaded coordination polymer composite materials with excellent stability exhibit significantly higher photocatalytic activities than the pure coordination polymer photocatalyst on the degradation of methyl orange (MO) under visible light irradiation. This enhancement can be ascribed to the introduction of PANI on the surface of the coordination polymer, which leads to efficient separation of photogenerated electron-hole pairs as well as a significant expansion of the photoresponse region. Finally, we discussed the influence of acidity on the morphology and photocatalytic activity of the composite material. An optimal condition to obtain the PANI loaded coordination polymer composite material with excellent photocatalytic activity has been obtained.

Preparation of polymer/LDH nanocomposite by UV-initiated photopolymerization of acrylate through photoinitiator-modified LDH precursor

International Nuclear Information System (INIS)

Hu, Lihua; Yuan, Yan; Shi, Wenfang

2011-01-01

Graphical abstract: This is the HR-TEM micrograph of UV cured nanocomposite at 5 wt% LDH-2959 loading for a-5 sample. The dark lines are the intersections of LDH platelets. It can be seen that samples a-5 dispersed in the polymer matrix and lost the ordered stacking-structure and show the completely exfoliation after UV curing. This can be explained by the fact that the sample a-5 only containing LDH-2959 exhibited a relative lower photopolymerization rate, which was propitious to further expand the LDH intergallery to form the exfoliated structure. Research highlights: → The UV cured polymer/LDH nanocomposites were prepared through the photopolymerization initiated by the photoinitiator-modified LDH precursor, LDH-2959. → The exfoliated UV cured nanocomposites were achieved in the presence of LDH-2959 only. However, the UV cured nanocomposites prepared using both LDH-2959 and Irgacure 2959 showed the intercalated structure. → Compared with the pure polymer, the exfoliated polymer/LDH nanocomposite showed remarkable enhanced thermal stability and mechanical properties because of their well dispersion in the polymer matrix. -- Abstract: The exfoliated polymer/layered double hydroxide (LDH) nanocomposite by UV-initiated photopolymerization of acrylate systems through an Irgacure 2959-modified LDH precursor (LDH-2959) as a photoinitiator complex was prepared. The LDH-2959 was obtained by the esterification of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959) with thioglycolic acid, following by the addition reaction with 3-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), finally intercalation into the sodium dodecyl sulfate-modified LDH. For comparison, the intercalated polymer/LDH nanocomposite was obtained with additive Irgacure 2959 addition. From the X-ray diffraction (XRD) measurements and HR-TEM observations, the LDH lost the ordered stacking-structure and well dispersed in the polymer matrix at 5 wt% LDH-2959 loading. The glass

Studies for the use of water soluble chelating polymer in ultra-filtration technique for the removal of uranium from aqueous solutions

International Nuclear Information System (INIS)

Misra, S.K.; Mahatele, A.K.; Tripathi, S.C.; Vijayan, K.; Munshi, S.K.

2005-01-01

Studies were carried out for the removal of uranium from aqueous medium using water soluble chelating polymer by ultra-filtration technique. The water soluble polymers are the option for the surfactants used in the micellar enhanced ultra-filtration technique. More than 95% separation of uranium carried out under different experimental conditions, suggest that the technique can be effectively employed for the removal uranium from the aqueous effluent streams. (author)

Spin coating of an evaporating polymer solution

KAUST Repository

Münch, Andreas

2011-01-01

We consider a mathematical model of spin coating of a single polymer blended in a solvent. The model describes the one-dimensional development of a thin layer of the mixture as the layer thins due to flow created by a balance of viscous forces and centrifugal forces and evaporation of the solvent. In the model both the diffusivity of the solvent in the polymer and the viscosity of the mixture are very rapidly varying functions of the solvent mass fraction. Guided by numerical solutions an asymptotic analysis reveals a number of different possible behaviours of the thinning layer dependent on the nondimensional parameters describing the system. The main practical interest is in controlling the appearance and development of a "skin" on the polymer where the solvent concentration reduces rapidly on the outer surface leaving the bulk of the layer still with high concentrations of solvent. In practice, a fast and uniform drying of the film is required. The critical parameters controlling this behaviour are found to be the ratio of the diffusion to advection time scales ε, the ratio of the evaporation to advection time scales δ and the ratio of the diffusivity of the pure polymer and the initial mixture exp(-1/γ). In particular, our analysis shows that for very small evaporation with δ

Relation between Streaming Potential and Streaming Electrification Generated by Streaming of Water through a Sandwich-type Cell

OpenAIRE

Maruyama, Kazunori; Nikaido, Mitsuru; Hara, Yoshinori; Tanizaki, Yoshie

2012-01-01

Both streaming potential and accumulated charge of water flowed out were measured simultaneously using a sandwich-type cell. The voltages generated in divided sections along flow direction satisfied additivity. The sign of streaming potential agreed with that of streaming electrification. The relation between streaming potential and streaming electrification was explained from a viewpoint of electrical double layer in glass-water interface.

Surface Initiated Polymerizations via e-ATRP in Pure Water

Directory of Open Access Journals (Sweden)

Seyed Schwan Hosseiny

2013-10-01

Full Text Available Here we describe the combined process of surface modification with electrochemical atom transfer radical polymerization (e-ATRP initiated from the surface of a modified gold-electrode in a pure aqueous solution without any additional supporting electrolyte. This approach allows for a very controlled growth of the polymer chains leading towards a steady increase in film thickness. Electrochemical quartz crystal microbalance displayed a highly regular increase in surface confined mass only after the addition of the pre-copper catalyst which is reduced in situ and transformed into the catalyst. Even after isolation and washing of the modified electrode surface, reinitiation was achieved with retention of the controlled electrochemical ATRP reaction. This reinitiation after isolation proves the livingness of the polymerization. This approach has interesting potential for smart thin film materials and offers also the possibility of post-modification via additional electrochemical induced reactions.

Host polymer influence on dilute polystyrene segmental dynamics

Science.gov (United States)

Lutz, T. R.

2005-03-01

We have utilized deuterium NMR to investigate the segmental dynamics of dilute (2%) d3-polystyrene (PS) chains in miscible polymer blends with polybutadiene, poly(vinyl ethylene), polyisoprene, poly(vinyl methylether) and poly(methyl methacrylate). In the dilute limit, we find qualitative differences depending upon whether the host polymer has dynamics that are faster or slower than that of pure PS. In blends where PS is the fast (low Tg) component, segmental dynamics are slowed upon blending and can be fit by the Lodge-McLeish model. When PS is the slow (high Tg) component, PS segmental dynamics speed up upon blending, but cannot be fit by the Lodge-McLeish model unless a temperature dependent self-concentration is employed. These results are qualitatively consistent with a recent suggestion by Kant, Kumar and Colby (Macromolecules, 2003, 10087), based upon data at higher concentrations. Furthermore, as the slow component, we find the segmental dynamics of PS has a temperature dependence similar to that of its host. This suggests viewing the high Tg component dynamics in a miscible blend as similar to a polymer in a low molecular weight solvent.

Polymers in cell encapsulation from an enveloped cell perspective.

Science.gov (United States)

de Vos, Paul; Lazarjani, Hamideh Aghajani; Poncelet, Denis; Faas, Marijke M

2014-04-01

In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone), polypropylene, sodium polystyrene sulfate, and polyacrylate poly(acrylonitrile-sodium methallylsulfonate). The biocompatibility of these polymers is discussed in terms of tissue responses in both the host and matrix to accommodate the functional survival of the cells. Cells should grow and function in the polymer network as adequately as in their natural environment. This is critical when therapeutic cells from scarce cadaveric donors are considered, such as pancreatic islets. Additionally, the cell mass in capsules is discussed from the perspective of emerging new insights into the release of so-called danger-associated molecular pattern molecules by clumps of necrotic therapeutic cells. We conclude that despite two decades of intensive research, drawing conclusions about which polymer is most adequate for clinical application is still difficult. This is because of the lack of documentation on critical information, such as the composition of the polymer, the presence or absence of confounding factors that induce immune responses, toxicity to enveloped cells, and the permeability of the polymer network. Only alginate has been studied extensively and currently qualifies for application. This review also discusses critical issues that are not directly related to polymers and are not discussed in the other reviews in this issue, such as the functional performance of encapsulated cells in vivo. Physiological endocrine responses may indeed not be expected because of the many barriers that the metabolites encounter when traveling from the blood stream to the enveloped cells and back to circulation. However, despite these diffusion barriers, many studies have shown optimal

Study of chemical-mineralogical properties of modified soils with polymers addition

Directory of Open Access Journals (Sweden)

Patricio Jonny

2016-01-01

Full Text Available On highways, the soil is considered a supported material and compound pavements layers. For this, they must have such characteristics that confer stability and mechanical resistance to traffic internal forces during the pavement life. When soils do not have required characteristics by the project can be used stabilization techniques that make the natural soil adequately to roads requirement. Based on this assumption, this study aimed to evaluate the efficacy of polymer association in soil stabilization for use in roads pavements. Were evaluated chemical and mineralogical properties on two (2 different soils with sample of pure soil and with the addition of the polymer association. Based on the obtained results, polymer association changes was observed on X-ray fluorescent spectrometry (XRF; X-ray diffraction (XRD; scanning electron microscopy (SEM and Methylene blue. In general, the polymeric association studied in this research was effective in chemical and mineralogical analyzes for use on stabilized soils, making this technique efficient for use in layers of road pavements.

Degradation of homogeneous polymer solutions in high shear turbulent pipe flow

Science.gov (United States)

Elbing, B. R.; Winkel, E. S.; Solomon, M. J.; Ceccio, S. L.

2009-12-01

This study quantifies degradation of polyethylene oxide (PEO) and polyacrylamide (PAM) polymer solutions in large diameter (2.72 cm) turbulent pipe flow at Reynolds numbers to 3 × 105 and shear rates greater than 105 1/s. The present results support a universal scaling law for polymer chain scission reported by Vanapalli et al. (2006) that predicts the maximum chain drag force to be proportional to Re 3/2, validating this scaling law at higher Reynolds numbers than prior studies. Use of this scaling gives estimated backbone bond strengths from PEO and PAM of 3.2 and 3.8 nN, respectively. Additionally, with the use of synthetic seawater as a solvent the onset of drag reduction occurred at higher shear rates relative to the pure water solvent solutions, but had little influence on the extent of degradation at higher shear rates. These results are significant for large diameter pipe flow applications that use polymers to reduce drag.

Polymer solidification of mixed wastes at the Rocky Flats Plant

International Nuclear Information System (INIS)

Faucette, A.M.; Logsdon, B.W.; Lucerna, J.J.; Yudnich, R.J.

1994-01-01

The Rocky Flats Plant is pursuing polymer solidification as a viable treatment option for several mixed waste streams that are subject to land disposal restrictions within the Resource Conservation and Recovery Act provisions. Tests completed to date using both surrogate and actual wastes indicate that polyethylene microencapsulation is a viable treatment option for several mixed wastes at the Rocky Flats Plant, including nitrate salts, sludges, and secondary wastes such as ash. Treatability studies conducted on actual salt waste demonstrated that the process is capable of producing waste forms that comply with all applicable regulatory criteria, including the Toxicity Characteristic Leaching Procedure. Tests have also been conducted to evaluate the feasibility of macroencapsulating certain debris wastes in polymers. Several methods and plastics have been tested for macroencapsulation, including post-consumer recycle and regrind polyethylene

Mechanism of radiation-induced degradation in mechanical properties of polymer matrix composites

International Nuclear Information System (INIS)

Egusa, Shigenori

1988-01-01

Four kinds of polymer matrix composites (filler, E-glass or carbon fibre cloth; matrix, epoxy or polyimide resin) and pure epoxy and polyimide resins were irradiated with 60 Co γ-rays or 2 MeV electrons at room temperature. Mechanical tests were then carried out at 77K and at room temperature. Following irradiation, the Young's (tensile) modulus of these composites and pure resins remains practically unchanged even at 170 MGy for both test temperatures. The ultimate strength, however, decreases appreciably with increasing dose. The dose dependence of the composite strength depends not only on the combination of fibre and matrix in the composite but also on the test temperature. A relationship is found between the composite ultimate strain and the matrix ultimate strain, thus indicating that the dose dependence of the composite strength is virtually determined by a change in the matrix ultimate strain due to irradiation. Based on this finding, we propose a mechanism of radiation-induced degradation of a polymer matrix composite in order to explain the dose dependence of the composite strength measured at 77 K and at room temperature. (author)

Preparation and application of PVDF-HFP composite polymer electrolytes in LiNi0.5Co0.2Mn0.3O2 lithium-polymer batteries

International Nuclear Information System (INIS)

Yang, Chun-Chen; Lian, Zuo-Yu; Lin, S.J.; Shih, Jeng-Ywan; Chen, Wei-Houng

2014-01-01

Graphical abstract: - Highlights: • PVDF-HFP/SBA15 membrane and NCM cathode material were prepared for Li ion battery. • SBA15 fillers can trap more liquid electrolytes to enhance the ionic conductivity. • Modified fillers with functional groups play a key role in reducing impedance. • LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer battery showed excellent electrochemical performance. - Abstract: This study reports the preparation of a composite polymer electrolyte for application in LiNi 0.5 Co 0.2 Mn 0.3 O 2 lithium-polymer batteries. Poly(vinylidiene fluoride-hexafluoropropylene) (denoted as PVDF-HFP) was used as the polymer host and mesoporous modified-silica fillers (denoted as m-SBA15) used as the solid plasticizer were added into the polymer matrix. The characteristic properties of the composite polymer membranes were examined using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and an AC impedance method. The discharge capacities of LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer batteries with a PE separator, pure PVDF-HFP polymer membrane, or a PVDF-HFP/10 wt.%m-SBA15 composite at 0.1 C were determined to be 155.5, 159.5, and 198.6 mAh g −1 , respectively. The LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer battery containing the PVDF-HFP/10 wt.%m-SBA15 composite achieved discharge capacities of 194, 170, 161, 150, 129, 115, and 87 mAh g −1 at 0.1, 0.2, 0.5, 1, 3, 5, and 10 C, respectively. The lithium-polymer battery demonstrated a high coulomb efficiency of ca. 99%. The PVDF-HFP/m-SBA15 composite membrane is a strong candidate for application in LiNi 0.5 Co 0.2 Mn 0.3 O 2 lithium-polymer batteries

StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

Science.gov (United States)

Li, Chenhui; Baciu, George; Han, Yu

2018-03-01

Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heat-map. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

International Nuclear Information System (INIS)

Rosario, F.; Casarin, S.A.; Agnelli, J.A.M.; Souza Junior, O.F. de

2010-01-01

This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

Analyzing indicators of stream health for Minnesota streams

Science.gov (United States)

Singh, U.; Kocian, M.; Wilson, B.; Bolton, A.; Nieber, J.; Vondracek, B.; Perry, J.; Magner, J.

2005-01-01

Recent research has emphasized the importance of using physical, chemical, and biological indicators of stream health for diagnosing impaired watersheds and their receiving water bodies. A multidisciplinary team at the University of Minnesota is carrying out research to develop a stream classification system for Total Maximum Daily Load (TMDL) assessment. Funding for this research is provided by the United States Environmental Protection Agency and the Minnesota Pollution Control Agency. One objective of the research study involves investigating the relationships between indicators of stream health and localized stream characteristics. Measured data from Minnesota streams collected by various government and non-government agencies and research institutions have been obtained for the research study. Innovative Geographic Information Systems tools developed by the Environmental Science Research Institute and the University of Texas are being utilized to combine and organize the data. Simple linear relationships between index of biological integrity (IBI) and channel slope, two-year stream flow, and drainage area are presented for the Redwood River and the Snake River Basins. Results suggest that more rigorous techniques are needed to successfully capture trends in IBI scores. Additional analyses will be done using multiple regression, principal component analysis, and clustering techniques. Uncovering key independent variables and understanding how they fit together to influence stream health are critical in the development of a stream classification for TMDL assessment.

Experimental study on the thermal and mechanical properties of MWCNT/polymer and Cu/polymer composites

International Nuclear Information System (INIS)

Park, Hyeon Jeong; Badakhsh, Arash; Im, Ik Tae; Kim, Min-Soo; Park, Chan Woo

2016-01-01

Highlights: • MWCNTs and Cu were ball milled with a variation of milling times. • Thermal conductivity and tensile strength of the PMCs were measured. • Cu reinforced HDPE showed thermal conductivity improvement ratios of up to 2.7. • MWCNT/HDPE showed higher thermal conductivity than MWCNT/PP. • MWCNT/HDPE was found to be mechanically stronger than Cu/HDPE. - Abstract: In this study, the influence of the different conditions of powder treatment on the thermal conductivity of nanocomposites was investigated. Carbon and metal-based polymer composite materials were produced and their thermal and mechanical characteristics were studied. For the fabrication of the composites, the study has explored and proposed the use of MWCNT and Cu as fillers in a polymer matrix. The polymer matrices were thermoplastic resins-polypropylene (PP) and high density polyethylene (HDPE). Ball milling was used as the mechanical method in order to enhance the dispersion of MWCNT and the transformation of the Cu particles. The ball milled MWCNT and Cu powder were examined by field emission scanning electron microscopy (FE-SEM). The thermal conductivity values of the resultant nanocomposites were determined by laser flash method (LFM), indicating the highest thermal conductivity is possessed by the polymer composite reinforced by the highest amount of 60 min-treated powder in every case studied. Comparing the obtained values for thermal conductivity with that of pure polymer the maximum improvements were found to be 105.1%, 79% and 271.5% for MWCNT/PP, MWCNT/HDPE and Cu/HDPE, respectively. Furthermore, experimental results were validated using the Agari-Uno and Nielsen-Lewis thermal conductivity models considering the shape of the filler. The results of deviation were found to be within the maximum 5% of the exact value implying a fine agreement between experimental and modeling data. Also, the tensile strength test was performed to evaluate the tensile strength of thermally

Mixtures of maximally entangled pure states

Energy Technology Data Exchange (ETDEWEB)

Flores, M.M., E-mail: mflores@nip.up.edu.ph; Galapon, E.A., E-mail: eric.galapon@gmail.com

2016-09-15

We study the conditions when mixtures of maximally entangled pure states remain entangled. We found that the resulting mixed state remains entangled when the number of entangled pure states to be mixed is less than or equal to the dimension of the pure states. For the latter case of mixing a number of pure states equal to their dimension, we found that the mixed state is entangled provided that the entangled pure states to be mixed are not equally weighted. We also found that one can restrict the set of pure states that one can mix from in order to ensure that the resulting mixed state is genuinely entangled. Also, we demonstrate how these results could be applied as a way to detect entanglement in mixtures of the entangled pure states with noise.

Development of polymer nanocomposites with regional bentonite clay

International Nuclear Information System (INIS)

Araujo, Edcleide M.; Leite, Amanda M.D.; Paz, Rene A. da; Medeiros, Keila M. de; Melo, Tomas J.A.; Barbosa, Josiane D.V.; Barbosa, Renata

2011-01-01

nanocomposites with regional bentonite clay were prepared by melt intercalation technique. The clays were studied without modification and modified with four quaternary ammonium salts. It was evidenced by X-ray diffraction that salts were incorporated into the clay structure thus confirming its organophilization. The nanocomposites were evaluated by means of thermal mechanic and flammability tests where presented properties significantly improved their pure polymers. The process of biodegradation of obtained bio nanocomposites was accelerated by the presence of clay. The produced membranes from nanocomposites have potential in the oil-water separation. (author)

Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

Science.gov (United States)

Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

2016-03-01

Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect. Copyright © 2015 Elsevier B.V. All rights reserved.

STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop

Energy Technology Data Exchange (ETDEWEB)

Fox, Geoffrey [Indiana Univ., Bloomington, IN (United States); Jha, Shantenu [Rutgers Univ., New Brunswick, NJ (United States); Ramakrishnan, Lavanya [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-10-01

The Department of Energy (DOE) Office of Science (SC) facilities including accelerators, light sources and neutron sources and sensors that study, the environment, and the atmosphere, are producing streaming data that needs to be analyzed for next-generation scientific discoveries. There has been an explosion of new research and technologies for stream analytics arising from the academic and private sectors. However, there has been no corresponding effort in either documenting the critical research opportunities or building a community that can create and foster productive collaborations. The two-part workshop series, STREAM: Streaming Requirements, Experience, Applications and Middleware Workshop (STREAM2015 and STREAM2016), were conducted to bring the community together and identify gaps and future efforts needed by both NSF and DOE. This report describes the discussions, outcomes and conclusions from STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop, the second of these workshops held on March 22-23, 2016 in Tysons, VA. STREAM2016 focused on the Department of Energy (DOE) applications, computational and experimental facilities, as well software systems. Thus, the role of “streaming and steering” as a critical mode of connecting the experimental and computing facilities was pervasive through the workshop. Given the overlap in interests and challenges with industry, the workshop had significant presence from several innovative companies and major contributors. The requirements that drive the proposed research directions, identified in this report, show an important opportunity for building competitive research and development program around streaming data. These findings and recommendations are consistent with vision outlined in NRC Frontiers of Data and National Strategic Computing Initiative (NCSI) [1, 2]. The discussions from the workshop are captured as topic areas covered in this report's sections. The report

Sulfur polymer cement for macroencapsulation of mixed waste debris

International Nuclear Information System (INIS)

Mattus, C.H.

1998-01-01

In FY 1997, the US DOE Mixed Waste Focus Area (MWFA) sponsored a demonstration of the macroencapsulation of mixed waste debris using sulfur polymer cement (SPC). Two mixed wastes were tested--a D006 waste comprised of sheets of cadmium and a D008/D009 waste comprised of lead pipes and joints contaminated with mercury. The demonstration was successful in rendering these wastes compliant with Land Disposal Restrictions (LDR), thereby eliminating one Mixed Waste Inventory Report (MWIR) waste stream from the national inventory

Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid.

Science.gov (United States)

Varaprasad, Kokkarachedu; Pariguana, Manuel; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi

2017-01-01

The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of a molecularly imprinted polymer for the extraction of kukoamine a from potato peels.

Science.gov (United States)

Piletska, Elena V; Burns, Rosemary; Terry, Leon A; Piletsky, Sergey A

2012-01-11

A molecularly imprinted polymer (MIP) for the purification of N(1),N(12)-bis(dihydrocaffeoyl)spermine (kukoamine A) was computationally designed and tested. The properties of the polymer were characterized. The protocol of the solid phase extraction (SPE) of kukoamine A from potato peels was optimized. A HPLC-MS method for the quantification of kukoamine A was developed and used for all optimization studies. The capacity of the MIP in relation to kukoamine A from the potato peels extract was estimated at 54 mg/g of the polymer. The kukoamine A purified from potato extract using MIP was exceptionally pure (≈ 90%). Although the corresponding blank polymer was less selective than the MIP for the extraction of kukoamine A from the potato extract, it was shown that the blank polymer could be effectively used for the purification of the crude synthetic kukoamine (polymer capacity = 80 mg of kukoamine A/g of the adsorbent, kukoamine A purity ≈ 86%). Therefore, selective adsorbents could be computationally designed for other plant products, allowing their purification in quantities that would be sufficient for more detailed studies and potential practical applications.

Ions-induced nanostructuration: effect of specific ionic adsorption on hydrophobic polymer surfaces.

Science.gov (United States)

Siretanu, Igor; Chapel, Jean-Paul; Bastos-González, Delfi; Drummond, Carlos

2013-06-06

The effect of surface charges on the ionic distribution in close proximity to an interface has been extensively studied. On the contrary, the influence of ions (from dissolved salts) on deformable interfaces has been barely investigated. Ions can adsorb from aqueous solutions on hydrophobic surfaces, generating forces that can induce long-lasting deformation of glassy polymer films, a process called ion-induced polymer nanostructuration, IPN. We have found that this process is ion-specific; larger surface modifications are observed in the presence of water ions and hydrophobic and amphiphilic ions. Surface structuration is also observed in the presence of certain salts of lithium. We have used streaming potential and atomic force microscopy to study the effect of dissolved ions on the surface properties of polystyrene films, finding a good correlation between ionic adsorption and IPN. Our results also suggest that the presence of strongly hydrated lithium promotes the interaction of anions with polystyrene surfaces and more generally with hydrophobic polymer surfaces, triggering then the IPN process.

The effect of silica toward polymer membrane for water separation process

Science.gov (United States)

Jamalludin, Mohd Riduan; Rosli, M. U.; Ishak, Muhammad Ikman; Khor, C. Y.; Shahrin, Suhaimi; Ismail, Ras Izzati; Lailina N., M.; Leng Y., L.; Jahidi, H.

2017-09-01

The aim of this present work was to investigate the effect of different percentage rice husk silica (RHS) particles composition towards polymer mixed matrix membrane microstructure and performance in water separation process. The polymer membranes were prepared by a phase inversion method using polysulfone (PSf), N-methyl-2-pyrrolidone (NMP) as solvent, distilled water as non-solvent and fixed RHS at 400°C as an additive. The microstructures of PSf/PEG/RHS sample were characterized by performing scanning electron microscope (SEM). The performance was measured by using pure water flux and humic acid for the rejection test. The analyzed result of SEM analysis revealed that the addition of RHS obviously improved the microstructure of the membrane especially at the top and sub layer at the range of 1 until 3 wt. %. This was proven by the pure water flux (PWF) value measured from 114.47 LMH to 154.04 LMH and rejection from value 83% to 96% at this specified range substantially higher than the mixed matrix membrane with synthetic silica. In fact, the presence of RHS particles not only improved the properties and performance of membrane but also possess biodegradable properties which can minimize the pollution and provide a membrane green technology system.

Influence of humidity on the phase behavior of API/polymer formulations.

Science.gov (United States)

Prudic, Anke; Ji, Yuanhui; Luebbert, Christian; Sadowski, Gabriele

2015-08-01

Amorphous formulations of APIs in polymers tend to absorb water from the atmosphere. This absorption of water can induce API recrystallization, leading to reduced long-term stability during storage. In this work, the phase behavior of different formulations was investigated as a function of relative humidity. Indomethacin and naproxen were chosen as model APIs and poly(vinyl pyrrolidone) (PVP) and poly(vinyl pyrrolidone-co-vinyl acetate) (PVPVA64) as excipients. The formulations were prepared by spray drying. The water sorption in pure polymers and in formulations was measured at 25°C and at different values of relative humidity (RH=25%, 50% and 75%). Most water was absorbed in PVP-containing systems, and water sorption was decreasing with increasing API content. These trends could also be predicted in good agreement with the experimental data using the thermodynamic model PC-SAFT. Furthermore, the effect of absorbed water on API solubility in the polymer and on the glass-transition temperature of the formulations was predicted with PC-SAFT and the Gordon-Taylor equation, respectively. The absorbed water was found to significantly decrease the API solubility in the polymer as well as the glass-transition temperature of the formulation. Based on a quantitative modeling of the API/polymer phase diagrams as a function of relative humidity, appropriate API/polymer compositions can now be selected to ensure long-term stable amorphous formulations at given storage conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Strong guided mode resonant local field enhanced visible harmonic generation in an azo-polymer resonant waveguide grating.

Science.gov (United States)

Lin, Jian Hung; Tseng, Chun-Yen; Lee, Ching-Ting; Young, Jeff F; Kan, Hung-Chih; Hsu, Chia Chen

2014-02-10

Guided mode resonance (GMR) enhanced second- and third-harmonic generation (SHG and THG) is demonstrated in an azo-polymer resonant waveguide grating (RWG), comprised of a poled azo-polymer layer on top of a textured SU8 substrate with a thin intervening layer of TiO2. Strong SHG and THG outputs are observed by matching either in-coming fundamental- or out-going harmonic-wavelength to the GMR wavelengths of the azo-polymer RWG. Without the azo-polymer coating, pure TiO2 RWGs, do not generate any detectable SHG using a fundamental beam peak intensity of 2 MW/cm(2). Without the textured TiO2 layer, a planar poled azo-polymer layer results in 3650 times less SHG than the full nonlinear RWG structure under identical excitation conditions. Rigorous coupled-wave analysis calculations confirm that this enhancement of the nonlinear conversion is due to strong local electric fields that are generated at the interfaces of the TiO2 and azo-polymer layers when the RWG is excited at resonant wavelengths associated with both SHG and THG conversion processes.

Interface engineering of perovskite solar cells with multifunctional polymer interlayer toward improved performance and stability

Science.gov (United States)

Huang, Li-Bo; Su, Pei-Yang; Liu, Jun-Min; Huang, Jian-Feng; Chen, Yi-Fan; Qin, Su; Guo, Jing; Xu, Yao-Wei; Su, Cheng-Yong

2018-02-01

This work proposes a new perovskite solar cell structure by inserting a polymer interlayer between perovskite and hole transporting material (HTM) to minimize the interface losses via interface engineering. The multifunctional interlayers improve the photovoltaic efficiency and device stability by shielding perovskite from moisture, suppressing charge combination, and promoting hole transport. The five different polymer layers are utilized to investigate the relationships of polymer structure, layer morphology and cell performance systematically. It is found that a reliable power conversion efficiency exceeding 19.0% is realized based on P3HT/spiro-OMeTAD composite structure, surpassing that of pure spiro-OMeTAD (15.0%). Moreover, the device with P3HT interlayer shows more brilliant long-term stability than that without interlayer when exposed into moisture. The enhanced device performance based on P3HT interlayer compared with the other polymers can be ascribed to the long hydrophobic alkyl chains and the small molecule monomers of P3HT, which contribute to self-assembly of the polymers into insulating layers and formation of the efficient π-π stacking in polymer/spiro-OMeTAD interface simultaneously. This study provides a practical route for the integration of a new class of easily-accessible, solution-processed interfacial polymer materials for high-performance and long-time stable PSC.

Plutonium and americium extraction studies with bifunctional organophosphorus extractants

International Nuclear Information System (INIS)

Navratil, J.D.

1985-01-01

Neutral bifunctional organophosphorus extractants, such as octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and dihexyl-N,N-diethylcarbamoylmethylphosphonate (CMP), are under study at the Rocky Flats Plant (RFP) to remove plutonium and americium from the 7M nitric acid waste. These compounds extract trivalent actinides from strong nitric acid, a property which distinguishes them from monofunctional organiphosphorus reagents. Furthermore, the reagents extract hydroytic plutonium (IV) polymer which is present in the acid waste stream. The compounds extract trivalent actinides with a 3:1 stoichiometry, whereas tetra- and hexavalent actinides extract with a stoichiometry of 2:1. Preliminary studies indicate that the extracted plutonium polymer complex contains one to two molecules of CMP per plutonium ion and the plutonium(IV) maintains a polymeric structure. Recent studies by Horwitz and co-workers conclude that the CMPO and CMP reagents behave as monodentate ligands. At RFP, three techniques are being tested for using CMP and CMPO to remove plutonium and americium from nitric acid waste streams. The different techniques are liquid-liquid extraction, extraction chromatography, and solid-supported liquid membranes. Recent tests of the last two techniques will be briefly described. In all the experiments, CMP was an 84% pure material from Bray Oil Co. and CMPO was 98% pure from M and T Chemicals

Shifting stream planform state decreases stream productivity yet increases riparian animal production

Science.gov (United States)

Venarsky, Michael P.; Walters, David M.; Hall, Robert O.; Livers, Bridget; Wohl, Ellen

2018-01-01

In the Colorado Front Range (USA), disturbance history dictates stream planform. Undisturbed, old-growth streams have multiple channels and large amounts of wood and depositional habitat. Disturbed streams (wildfires and logging tested how these opposing stream states influenced organic matter, benthic macroinvertebrate secondary production, emerging aquatic insect flux, and riparian spider biomass. Organic matter and macroinvertebrate production did not differ among sites per unit area (m−2), but values were 2 ×–21 × higher in undisturbed reaches per unit of stream valley (m−1 valley) because total stream area was higher in undisturbed reaches. Insect emergence was similar among streams at the per unit area and per unit of stream valley. However, rescaling insect emergence to per meter of stream bank showed that the emerging insect biomass reaching the stream bank was lower in undisturbed sites because multi-channel reaches had 3 × more stream bank than single-channel reaches. Riparian spider biomass followed the same pattern as emerging aquatic insects, and we attribute this to bottom-up limitation caused by the multi-channeled undisturbed sites diluting prey quantity (emerging insects) reaching the stream bank (riparian spider habitat). These results show that historic landscape disturbances continue to influence stream and riparian communities in the Colorado Front Range. However, these legacy effects are only weakly influencing habitat-specific function and instead are primarily influencing stream–riparian community productivity by dictating both stream planform (total stream area, total stream bank length) and the proportional distribution of specific habitat types (pools vs riffles).

Shifting stream planform state decreases stream productivity yet increases riparian animal production

Science.gov (United States)

Venarsky, Michael P.; Walters, David M.; Hall, Robert O.; Livers, Bridget; Wohl, Ellen

2018-01-01

In the Colorado Front Range (USA), disturbance history dictates stream planform. Undisturbed, old-growth streams have multiple channels and large amounts of wood and depositional habitat. Disturbed streams (wildfires and logging production, emerging aquatic insect flux, and riparian spider biomass. Organic matter and macroinvertebrate production did not differ among sites per unit area (m−2), but values were 2 ×–21 × higher in undisturbed reaches per unit of stream valley (m−1 valley) because total stream area was higher in undisturbed reaches. Insect emergence was similar among streams at the per unit area and per unit of stream valley. However, rescaling insect emergence to per meter of stream bank showed that the emerging insect biomass reaching the stream bank was lower in undisturbed sites because multi-channel reaches had 3 × more stream bank than single-channel reaches. Riparian spider biomass followed the same pattern as emerging aquatic insects, and we attribute this to bottom-up limitation caused by the multi-channeled undisturbed sites diluting prey quantity (emerging insects) reaching the stream bank (riparian spider habitat). These results show that historic landscape disturbances continue to influence stream and riparian communities in the Colorado Front Range. However, these legacy effects are only weakly influencing habitat-specific function and instead are primarily influencing stream–riparian community productivity by dictating both stream planform (total stream area, total stream bank length) and the proportional distribution of specific habitat types (pools vs riffles).

ADAPTIVE STREAMING OVER HTTP (DASH UNTUK APLIKASI VIDEO STREAMING

Directory of Open Access Journals (Sweden)

I Made Oka Widyantara

2015-12-01

Full Text Available This paper aims to analyze Internet-based streaming video service in the communication media with variable bit rates. The proposed scheme on Dynamic Adaptive Streaming over HTTP (DASH using the internet network that adapts to the protocol Hyper Text Transfer Protocol (HTTP. DASH technology allows a video in the video segmentation into several packages that will distreamingkan. DASH initial stage is to compress the video source to lower the bit rate video codec uses H.26. Video compressed further in the segmentation using MP4Box generates streaming packets with the specified duration. These packages are assembled into packets in a streaming media format Presentation Description (MPD or known as MPEG-DASH. Streaming video format MPEG-DASH run on a platform with the player bitdash teritegrasi bitcoin. With this scheme, the video will have several variants of the bit rates that gave rise to the concept of scalability of streaming video services on the client side. The main target of the mechanism is smooth the MPEG-DASH streaming video display on the client. The simulation results show that the scheme based scalable video streaming MPEG-DASH able to improve the quality of image display on the client side, where the procedure bufering videos can be made constant and fine for the duration of video views

Properties of polymer-silver nanocomposites fabricated by co-sputtering; Eigenschaften von Polymer-Silber-Nanokompositen hergestellt durch Co-Sputtern

Energy Technology Data Exchange (ETDEWEB)

Schuermann, Ulrich

2006-07-01

In this thesis polymer-metal nanocomposites were fabricated by simultaneous sputtering of silver and polymers from two independent magnetron sputtering sources. By the netted structure and the dielectric properties PTFE is suited for the use as matrix material. The metal content of the composite films was determined via the measurement of EDX intensities. The size of the nanoparticles was determined by means of TEM and XRD and lies in the range of 10 nm. The composite materials show at the percolation limit a sudden transition of the properties from polymer- to metal-like behaviour. The specific resistance decreases in a range between 35 and 40 % silver content by at least nine orders of magnitude. The optical properties change with the metal content. The absorption caused by plasmon resonance, which has at small filling degrees its maximum at about 000 nm and has an intense yellow colour of the composite material as consequence shifts with increasing silver content to longer wavelengths. The difference in the optical.behaviour of the nanocomposites and the pure polymers can be used for the fabrication of Bragg reflectors. Small changes in the metal content can in the polymer-silver nanocomposites in the range of the percolation threshold effect a drastic change in ther properties, by which applications as sensors are thinkable. [German] In dieser Arbeit wurden Polymer-Metall-Nanokomposite durch gleichzeitiges Sputtern von Silber und Polymeren aus zwei unabhaengigen Magnetron-Sputterquellen hergestellt. Durch die vernetzte Struktur und die dielektrischen Eigenschaften eignet sich PTFE zur Verwendung als Matrixmaterial. Der Metallgehalt der Kompositfilme wurde ueber die Messung von EDX-Intensitaeten ermittelt. Die Groesse der Nanopartikel wurde mit Hilfe von TEM und XRD bestimmt und liegt im Bereich von 10 nm. Die Kompositmaterialien zeigen an der Perkolationsgrenze einen schlagartigen Uebergang der Eigenschaften vom polymer- zum metallaehnlichen Verhalten. Der

The Role of Nanofillers in Polymer Nanocomposites

Science.gov (United States)

Xu, Di

Polymer nanocomposites have been widely used in many fields. By introducing nanoparticles as fillers, researchers are able to get reinforced materials and new materials with novel properties, such as stronger mechanics, enhanced optical properties and improved conductivity. Though experimental techniques have rapidly advanced to enable better control of materials at atomic level, there is still a lack of a fundamental understanding of the dynamics and structure-properties relations in polymer nanocomposites. In this thesis, we use computer simulations to study the molecular structure and connections between microstate to macro properties of a variety of nanocomposites. Our goal is to understand the role of nanofillers in complex nanocomposite systems and to assist nanocomposite design. Nanoplatelet fillers, such as clays, have shown superior effects on the properties of polymer gels. We used molecular dynamic simulation to study nanoplatelet-filled composite gel system, in which short-range attraction exists between the polymer and nanoplatelet fillers. We show that the polymers and nanoplatelet fillers formed organic-inorganic networks with nanoplatelets acting as crosslink junctions, and the network eventually percolates the system as fillers reached a critical concentration. Stress auto-correlation and step-strain test were applied to investigate the mechanical properties; the results show the simulated composites changed from fluid-like to solid-like. The mechanical changes were consistent with the percolation transition, and gelation mechanism was therefore believed to be similar to those pure polymer physical gels. It was observed platelets aggregated into a local intercalation structure, which significantly differs from typical spherical fillers. This unique intercalation structure was examined by radial distribution function and ordering parameters. We discussed how intercalation would affect the properties of the platelet composites by comparing them with

Polymer nanocomposites: polymer and particle dynamics

KAUST Repository

Kim, Daniel

2012-01-01

Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

Gas-Transport-Property Performance of Hybrid Carbon Molecular Sieve−Polymer Materials

KAUST Repository

Das, Mita

2010-10-06

High-performance hybrid materials using carbon molecular sieve materials and 6FDA-6FpDA were produced. A detailed analysis of the effects of casting processes and the annealing temperature is reported. Two existing major obstacles, sieve agglomeration and residual stress, were addressed in this work, and subsequently a new membrane formation technique was developed to produce high-performing membranes. The successfully improved interfacial region of the hybrid membranes allows the sieves to increase the selectivity of the membranes above the neat polymer properties. Furthermore, an additional performance enhancement was seen with increased sieve loading in the hybrid membranes, leading to an actual performance above the upper bound for pure polymer membranes. The membranes were also tested under a mixed-gas environment, which further demonstrated promising results. © 2010 American Chemical Society.

Akamai Streaming

OpenAIRE

ECT Team, Purdue

2007-01-01

Akamai offers world-class streaming media services that enable Internet content providers and enterprises to succeed in today's Web-centric marketplace. They deliver live event Webcasts (complete with video production, encoding, and signal acquisition services), streaming media on demand, 24/7 Webcasts and a variety of streaming application services based upon their EdgeAdvantage.

An Eulerian description of the streaming process in the lattice Boltzmann equation

CERN Document Server

Lee Tae Hun

2003-01-01

This paper presents a novel strategy for solving discrete Boltzmann equation (DBE) for simulation of fluid flows. This strategy splits the solution procedure into streaming and collision steps as in the lattice Boltzmann equation (LBE) method. The streaming step can then be carried out by solving pure linear advection equations in an Eulerian framework. This offers two significant advantages over previous methods. First, the relationship between the relaxation parameter and the discretization of the collision term developed from the LBE method is directly applicable to the DBE method. The resulting DBE collision step remains local and poses no constraint on time step. Second, decoupling of the advection step from the collision step facilitates implicit discretization of the advection equation on arbitrary meshes. An implicit unstructured DBE method is constructed based on this strategy and is evaluated using several test cases of flow over a backward-facing step, lid-driven cavity flow, and flow past a circul...

Perspectives on the Pure-Tone Audiogram.

Science.gov (United States)

Musiek, Frank E; Shinn, Jennifer; Chermak, Gail D; Bamiou, Doris-Eva

The pure-tone audiogram, though fundamental to audiology, presents limitations, especially in the case of central auditory involvement. Advances in auditory neuroscience underscore the considerably larger role of the central auditory nervous system (CANS) in hearing and related disorders. Given the availability of behavioral audiological tests and electrophysiological procedures that can provide better insights as to the function of the various components of the auditory system, this perspective piece reviews the limitations of the pure-tone audiogram and notes some of the advantages of other tests and procedures used in tandem with the pure-tone threshold measurement. To review and synthesize the literature regarding the utility and limitations of the pure-tone audiogram in determining dysfunction of peripheral sensory and neural systems, as well as the CANS, and to identify other tests and procedures that can supplement pure-tone thresholds and provide enhanced diagnostic insight, especially regarding problems of the central auditory system. A systematic review and synthesis of the literature. The authors independently searched and reviewed literature (journal articles, book chapters) pertaining to the limitations of the pure-tone audiogram. The pure-tone audiogram provides information as to hearing sensitivity across a selected frequency range. Normal or near-normal pure-tone thresholds sometimes are observed despite cochlear damage. There are a surprising number of patients with acoustic neuromas who have essentially normal pure-tone thresholds. In cases of central deafness, depressed pure-tone thresholds may not accurately reflect the status of the peripheral auditory system. Listening difficulties are seen in the presence of normal pure-tone thresholds. Suprathreshold procedures and a variety of other tests can provide information regarding other and often more central functions of the auditory system. The audiogram is a primary tool for determining type

Generalized pure Lovelock gravity

Science.gov (United States)

Concha, Patrick; Rodríguez, Evelyn

2017-11-01

We present a generalization of the n-dimensional (pure) Lovelock Gravity theory based on an enlarged Lorentz symmetry. In particular, we propose an alternative way to introduce a cosmological term. Interestingly, we show that the usual pure Lovelock gravity is recovered in a matter-free configuration. The five and six-dimensional cases are explicitly studied.

Structural and optical characterization of PVA:KMnO4 based solid polymer electrolyte

Directory of Open Access Journals (Sweden)

Omed Gh. Abdullah

Full Text Available Solid polymer electrolyte films of polyvinyl alcohol (PVA doped with a different weight percent of potassium permanganate (KMnO4 were prepared by standard solution cast method. XRD and FTIR techniques were performed for structural study. Complex formation between the PVA polymer and KMnO4 salt was confirmed by Fourier transform infrared (FTIR spectroscopy. The description of crystalline nature of the solid polymer electrolyte films has been confirmed by XRD analysis. The UV-Visible absorption spectra were analyzed in terms of absorption formula for non-crystalline materials. The fundamental optical parameters such as optical band gap energy, refractive index, optical conductivity, and dielectric constants have been investigated and showed a clear dependence on the KMnO4 concentration. The observed value of optical band gap energy for pure PVA is about 6.27 eV and decreases to a value 3.12 eV for the film sample formed with 4 wt% KMnO4 salt. The calculated values of refractive index and the dielectric constants of the polymer electrolyte films increase with increasing KMnO4 content. Keywords: Solid polymer electrolyte, XRD analysis, FTIR study, Optical band gap, Dielectric constant, Refractive index

Role of architecture in the elastic response of semiflexible polymer and fiber networks

Science.gov (United States)

Heussinger, Claus; Frey, Erwin

2007-01-01

We study the elasticity of cross-linked networks of thermally fluctuating stiff polymers. As compared to their purely mechanical counterparts, it is shown that these thermal networks have a qualitatively different elastic response. By accounting for the entropic origin of the single-polymer elasticity, the networks acquire a strong susceptibility to polydispersity and structural randomness that is completely absent in athermal models. In extensive numerical studies we systematically vary the architecture of the networks and identify a wealth of phenomena that clearly show the strong dependence of the emergent macroscopic moduli on the underlying mesoscopic network structure. In particular, we highlight the importance of the polymer length, which to a large extent controls the elastic response of the network, surprisingly, even in parameter regions where it does not enter the macroscopic moduli explicitly. Understanding these subtle effects is only possible by going beyond the conventional approach that considers the response of typical polymer segments only. Instead, we propose to describe the elasticity in terms of a typical polymer filament and the spatial distribution of cross-links along its backbone. We provide theoretical scaling arguments to relate the observed macroscopic elasticity to the physical mechanisms on the microscopic and mesoscopic scales.

The Midwest Stream Quality Assessment—Influences of human activities on streams

Science.gov (United States)

Van Metre, Peter C.; Mahler, Barbara J.; Carlisle, Daren M.; Coles, James F.

2018-04-16

Healthy streams and the fish and other organisms that live in them contribute to our quality of life. Extensive modification of the landscape in the Midwestern United States, however, has profoundly affected the condition of streams. Row crops and pavement have replaced grasslands and woodlands, streams have been straightened, and wetlands and fields have been drained. Runoff from agricultural and urban land brings sediment and chemicals to streams. What is the chemical, physical, and biological condition of Midwestern streams? Which physical and chemical stressors are adversely affecting biological communities, what are their origins, and how might we lessen or avoid their adverse effects?In 2013, the U.S. Geological Survey (USGS) conducted the Midwest Stream Quality Assessment to evaluate how human activities affect the biological condition of Midwestern streams. In collaboration with the U.S. Environmental Protection Agency National Rivers and Streams Assessment, the USGS sampled 100 streams, chosen to be representative of the different types of watersheds in the region. Biological condition was evaluated based on the number and diversity of fish, algae, and invertebrates in the streams. Changes to the physical habitat and chemical characteristics of the streams—“stressors”—were assessed, and their relation to landscape factors and biological condition was explored by using mathematical models. The data and models help us to better understand how the human activities on the landscape are affecting streams in the region.

Generalized pure Lovelock gravity

Directory of Open Access Journals (Sweden)

Patrick Concha

2017-11-01

Full Text Available We present a generalization of the n-dimensional (pure Lovelock Gravity theory based on an enlarged Lorentz symmetry. In particular, we propose an alternative way to introduce a cosmological term. Interestingly, we show that the usual pure Lovelock gravity is recovered in a matter-free configuration. The five and six-dimensional cases are explicitly studied.

Analysis of hydraulic characteristics for stream diversion in small stream

Energy Technology Data Exchange (ETDEWEB)

Ahn, Sang-Jin; Jun, Kye-Won [Chungbuk National University, Cheongju(Korea)

2001-10-31

This study is the analysis of hydraulic characteristics for stream diversion reach by numerical model test. Through it we can provide the basis data in flood, and in grasping stream flow characteristics. Analysis of hydraulic characteristics in Seoknam stream were implemented by using computer model HEC-RAS(one-dimensional model) and RMA2(two-dimensional finite element model). As a result we became to know that RMA2 to simulate left, main channel, right in stream is more effective method in analysing flow in channel bends, steep slope, complex bed form effect stream flow characteristics, than HEC-RAS. (author). 13 refs., 3 tabs., 5 figs.

Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

International Nuclear Information System (INIS)

Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N.; Das, Sadananda; Pandey, Ashok K.; Kumar, Sangita D.; Reddy, A.V.R.

2012-01-01

Highlights: ► Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ► Membranes offered high capacity and selectivity for fluoride in aqueous media. ► Quantitative uptake (80 ± 5%) of fluoride. ► Fast sorption kinetics. ► Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ≈76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg −1 ), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

The metaphors we stream by: Making sense of music streaming

OpenAIRE

Hagen, Anja Nylund

2016-01-01

In Norway music-streaming services have become mainstream in everyday music listening. This paper examines how 12 heavy streaming users make sense of their experiences with Spotify and WiMP Music (now Tidal). The analysis relies on a mixed-method qualitative study, combining music-diary self-reports, online observation of streaming accounts, Facebook and last.fm scrobble-logs, and in-depth interviews. By drawing on existing metaphors of Internet experiences we demonstrate that music-streaming...

Local impact of humidification on degradation in polymer electrolyte fuel cells

Science.gov (United States)

Sanchez, Daniel G.; Ruiu, Tiziana; Biswas, Indro; Schulze, Mathias; Helmly, Stefan; Friedrich, K. Andreas

2017-06-01

The water level in a polymer electrolyte membrane fuel cell (PEMFC) affects the durability as is seen from the degradation processes during operation a PEMFC with fully- and nonhumidified gas streams as analyzed using an in-situ segmented cell for local current density measurements during a 300 h test operating under constant conditions and using ex situ SEM/EDX and XPS post-test analysis of specific regions. The impact of the RH on spatial distribution of the degradation process results from different water distribution giving different chemical environments. Under nonhumidified gas streams, the cathode inlet region exhibits increased degradation, whereas with fully humidified gases the bottom of the cell had the higher performance losses. The degradation and the degree of reversibility produced by Pt dissolution, PTFE defluorination, and contaminants such as silicon (Si) and nickel (Ni) were locally evaluated.

Extraction of zirconium from raffinate stream of Zirconium Oxide Plant raffinate

International Nuclear Information System (INIS)

Pandey, Garima; Chinchale, R.; Renjith, A.U.; Mukhopadhyay, S.; Shenoy, K.T.; Ghosh, S.K.

2013-01-01

Recovery of metals from dilute streams is a major task in nuclear industry in the view of environmental remediation and value recovery. Presently solvent extraction process is employed on the commercial scale to recover nuclear pure zirconium using TBP as extractant. The waste stream of TBP extraction process contains about 1.2 gpl of Zirconium in nitrate form. At present there is no process to recover Zirconium from this raffinate stream. Hence, under the present study recovery of zirconium from the raffinate stream of Zirconium Oxide Plant Raffinate has been investigated. TBP, which is the most commonly used solvent in the nuclear industry is not suitable for the extraction of zirconium from lean solution at low acidity as its distribution coefficient is less than one. In search of a suitable extractant Mixed Alkyl Phosphine Oxide (MAPO) was investigated as potential carrier. Parametric batch studies for various equilibrium data like extractant concentration, strippant concentration, solvent reusability, equilibration time, acidity etc. were done to optimize the process condition. For the distribution studies, equal volumes of the raffinate and organic phase were shaken at room temperature in digital wrist action shaker for 10 minutes to ensure complete equilibrium. It was found that 0.1 M MAPO in 80:20 dodecane: isodecanol is suitable for extraction of Zr at 2 N acidity. 0.1 M MAPO gives distribution coefficient in the range of 12-15 for Zr. The slope of log-log plot between MAPO concentration and K, suggests involvement of 3 molecules of MAPO in the formation of extracting species. 0.2 M Oxalic acid was able to completely back extract Zr from the organic phase into aqueous phase. Also good regeneration capacity of MAPO projects its potential to be used as extractant for the process. Based on the equilibrium studies, Dispersion Liquid Membrane configuration in hollow fiber contactor was explored for the extraction of Zirconium from Zirconium Nitrate Pure

Studies on the Properties of Plasticizer and Lithium Salt on PMMA-based Solid Polymer Electrolytes

International Nuclear Information System (INIS)

Chew, K. W.; Tan, C. G.; Osman, Z.

2010-01-01

The effects of plasticizer and lithium salt on PMMA-based solid polymer electrolyte have been investigated. In current project, three system samples consisted of pure poly(methyl methacrylate (PMMA) system, plasticized poly(methyl methacrylate)(PMMA-EC) system and the LiCF 3 SO 3 salted-poly(methyl methacrylate) containing a fixed amount of plasticizer ([PMMA-EC]-LiCF 3 SO 3 ) system have been prepared using solution casting technique. The conductivities of the films from each system are characterized by impedance spectroscopy and infrared spectrum. With the addition of plasticizer, results show improvement on the ionic conductivity value where the value of 6.25x10 -10 Scm -1 is obtained. This may be due to the nature of plasticizer that softens the polymer and hence enhanced the ionic transportation across the polymer. The room temperature conductivity for the highest conducting sample in the ([PMMA-EC]-LiCF 3 SO 3 ) system is 1.36x10 -5 Scm -1 . Fourier Transform Infrared Spectroscopy (FTIR) indicates complexation between the polymer and the plasticizer and the polymer, the plasticizer and the salts, and the result of XRD further supports the observation.

Musical notation reading in pure alexia

DEFF Research Database (Denmark)

Starrfelt, Randi; Wong, Yetta K.

2017-01-01

Pure alexia (PA) is an acquired reading disorder following lesions to left ventral temporo-occipital cortex. Patients with PA read slowly but correctly, and show an abnormal effect of word length on RTs. However, it is unclear how pure alexia may affect musical notation reading. We report a pure...

A Comparative Study on Formation of Polar Components, Fatty Acids and Sterols during Frying of Refined Olive Pomace Oil Pure and Its Blend Coconut Oil.

Science.gov (United States)

Ben Hammouda, Ibtissem; Triki, Mehdi; Matthäus, Bertrand; Bouaziz, Mohamed

2018-04-04

The frying performance of pure refined olive-pomace oil (ROPO) and blended with refined coconut oil (RCO) (80:20) was compared during a frying operation of French fries at 180 °C. Blending polyunsaturated oils with highly saturated or monounsaturated oils has been studied extensively, however in literature there is no study has been reported so far on blending ROPO (rich in monounsaturated fatty acids) with RCO (rich in saturated fatty acids) to formulate new frying oils. At the end of the frying process, the blend of ROPO/RCO exhibited a higher chemical stability than the pure ROPO based on total polar compounds (TPC), and polymers. The rate of TPC formation was achieved 23.3% and 30.6% for the blend and the pure oil, respectively. Trans and free fatty acids content, as well as anisidine value were also observed to be the highest in the pure ROPO. This study evaluated the frying performance in the search for appropriate frying oils to deliver healthy fried products with optimized nutritional qualities.

A Close Look at Charge Generation in Polymer:Fullerene Blends with Microstructure Control

KAUST Repository

Scarongella, Mariateresa

2015-03-04

© 2015 American Chemical Society. We reveal some of the key mechanisms during charge generation in polymer:fullerene blends exploiting our well-defined understanding of the microstructures obtained in pBTTT:PCBM systems via processing with fatty acid methyl ester additives. Based on ultrafast transient absorption, electro-absorption, and fluorescence up-conversion spectroscopy, we find that exciton diffusion through relatively phase-pure polymer or fullerene domains limits the rate of electron and hole transfer, while prompt charge separation occurs in regions where the polymer and fullerene are molecularly intermixed (such as the co-crystal phase where fullerenes intercalate between polymer chains in pBTTT:PCBM). We moreover confirm the importance of neat domains, which are essential to prevent geminate recombination of bound electron-hole pairs. Most interestingly, using an electro-absorption (Stark effect) signature, we directly visualize the migration of holes from intermixed to neat regions, which occurs on the subpicosecond time scale. This ultrafast transport is likely sustained by high local mobility (possibly along chains extending from the co-crystal phase to neat regions) and by an energy cascade driving the holes toward the neat domains.

A Close Look at Charge Generation in Polymer:Fullerene Blends with Microstructure Control

KAUST Repository

Scarongella, Mariateresa; De Jonghe-Risse, Jelissa; Buchaca-Domingo, Ester; Causa’ , Martina; Fei, Zhuping; Heeney, Martin; Moser, Jacques-E.; Stingelin, Natalie; Banerji, Natalie

2015-01-01

© 2015 American Chemical Society. We reveal some of the key mechanisms during charge generation in polymer:fullerene blends exploiting our well-defined understanding of the microstructures obtained in pBTTT:PCBM systems via processing with fatty acid methyl ester additives. Based on ultrafast transient absorption, electro-absorption, and fluorescence up-conversion spectroscopy, we find that exciton diffusion through relatively phase-pure polymer or fullerene domains limits the rate of electron and hole transfer, while prompt charge separation occurs in regions where the polymer and fullerene are molecularly intermixed (such as the co-crystal phase where fullerenes intercalate between polymer chains in pBTTT:PCBM). We moreover confirm the importance of neat domains, which are essential to prevent geminate recombination of bound electron-hole pairs. Most interestingly, using an electro-absorption (Stark effect) signature, we directly visualize the migration of holes from intermixed to neat regions, which occurs on the subpicosecond time scale. This ultrafast transport is likely sustained by high local mobility (possibly along chains extending from the co-crystal phase to neat regions) and by an energy cascade driving the holes toward the neat domains.

Conductivity and optical studies of plasticized solid polymer electrolytes doped with carbon nanotube

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Suriani, E-mail: sue_83@um.edu.my [Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ahmad, Roslina; Johan, Mohd Rafie [Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2012-01-15

Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF{sub 6}), ethylene carbonate (EC) and amorphous carbon nanotube ({alpha}CNTs) were prepared by the solution cast technique. The conductivity increases from 10{sup -10} to 10{sup -5} Scm{sup -1} upon the addition of salt. The incorporation of EC and {alpha}CNTs to the salted polymer enhances the conductivity significantly to 10{sup -4} and 10{sup -3} Scm{sup -1}. The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200-400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping. - Highlights: > Optical band gap values show the decreasing trend with an increasing dopant concentration. > It is also observed that the absorption edge shifted to longer wavelength on doping. > Results of the optical measurements indicate the presence of a well-defined {pi}{yields}{pi}* transition associated with the formation of a conjugated C=O and/or C=O electronic structure.

Conductivity and optical studies of plasticized solid polymer electrolytes doped with carbon nanotube

International Nuclear Information System (INIS)

Ibrahim, Suriani; Ahmad, Roslina; Johan, Mohd Rafie

2012-01-01

Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF 6 ), ethylene carbonate (EC) and amorphous carbon nanotube (αCNTs) were prepared by the solution cast technique. The conductivity increases from 10 -10 to 10 -5 Scm -1 upon the addition of salt. The incorporation of EC and αCNTs to the salted polymer enhances the conductivity significantly to 10 -4 and 10 -3 Scm -1 . The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200-400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping. - Highlights: → Optical band gap values show the decreasing trend with an increasing dopant concentration. → It is also observed that the absorption edge shifted to longer wavelength on doping. → Results of the optical measurements indicate the presence of a well-defined π→π* transition associated with the formation of a conjugated C=O and/or C=O electronic structure.

Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems

Science.gov (United States)

Mittelsteadt, Cortney K.; Braff, William

2009-01-01

In a substantial improvement over present alkaline systems, an advanced hybrid bipolar plate for a unitized fuel cell/electrolyzer has been developed. This design, which operates on pure feed streams (H2/O2 and water, respectively) consists of a porous metallic foil filled with a polymer that has very high water transport properties. Combined with a second metallic plate, the pore-filled metallic plates form a bipolar plate with an empty cavity in the center.

Particle size dependence of the Young's modulus of filled polymers: 2. Annealing and solid-state nuclear magnetic resonance experiments

NARCIS (Netherlands)

Vollenberg, P.H.T.; Haan, de J.W.; Ven, van de L.J.M.; Heikens, D.

1989-01-01

Experimental results are reported from which it appears that in the case of polymer filled with silane-treated glass beads the Young's modulus is, in accordance with present theory, independent of the particle size of the filler. However, if pure glass beads are used as filler, the Young's modulus

Pure homology of algebraic varieties

OpenAIRE

Weber, Andrzej

2003-01-01

We show that for a complete complex algebraic variety the pure component of homology coincides with the image of intersection homology. Therefore pure homology is topologically invariant. To obtain slightly more general results we introduce "image homology" for noncomplete varieties.

Polymer-ceramic nanocomposites for applications in the bone surgery

Science.gov (United States)

Stodolak, E.; Gadomska, K.; Lacz, A.; Bogun, M.

2009-01-01

The subject of this work was preparation and investigation of properties of a nanocomposite material based on polymer matrix modified with nanometric silica particles (SiO2). The composite matrix consisted of resorbable P(L/DL)LA polymer with certified biocompatibility. Nanometric silica was introduced into the matrix by means of ultrasonic homogenisation and/or mechanical stirring. The silica was introduced directly e.g. as nanoparticles or inside calcium alginate fibres which contained 3 wt.% of amorphous SiO2. Proper dispersion of nano-filliers was confirmed by means of thermal analysis (TG/DTA, DSC). It was observed, that the presence of inorganic nanoparticles influenced several surface parameters of the nanocomposites i.e. hydrophility (a decrease of surface energy) and topography (both in micro- and nano-scale). Additionally, the nanocomposites exhibited enhanced mechanical properties (Young's modulus, tensile strength) compared to the pure polymer. The nanocomposites were bioactive materials (SBF/3 days/37oC). Biological tests (MTT test) showed a good viability of human osteoblasts (hFOB 1.19) in contact with the nanocomposites surface. Results of preliminary biological tests carried out with the use of mother cells extracted from human bone marrow showed that the nanocomposites may provide differenation of bone cells.

Polymer-ceramic nanocomposites for applications in the bone surgery

International Nuclear Information System (INIS)

Stodolak, E; Gadomska, K; Lacz, A; Bogun, M

2009-01-01

The subject of this work was preparation and investigation of properties of a nanocomposite material based on polymer matrix modified with nanometric silica particles (SiO 2 ). The composite matrix consisted of resorbable P(L/DL)LA polymer with certified biocompatibility. Nanometric silica was introduced into the matrix by means of ultrasonic homogenisation and/or mechanical stirring. The silica was introduced directly e.g. as nanoparticles or inside calcium alginate fibres which contained 3 wt.% of amorphous SiO 2 . Proper dispersion of nano-filliers was confirmed by means of thermal analysis (TG/DTA, DSC). It was observed, that the presence of inorganic nanoparticles influenced several surface parameters of the nanocomposites i.e. hydrophility (a decrease of surface energy) and topography (both in micro- and nano-scale). Additionally, the nanocomposites exhibited enhanced mechanical properties (Young's modulus, tensile strength) compared to the pure polymer. The nanocomposites were bioactive materials (SBF/3 days/37 deg. C). Biological tests (MTT test) showed a good viability of human osteoblasts (hFOB 1.19) in contact with the nanocomposites surface. Results of preliminary biological tests carried out with the use of mother cells extracted from human bone marrow showed that the nanocomposites may provide differenation of bone cells.

Blood stream infection by an emerging pathogen Oligella ureolytica in a cancer patient: Case report and review of literature

Directory of Open Access Journals (Sweden)

Frincy K Baruah

2014-01-01

Full Text Available Oligella ureolytica is an emerging bacteria rarely implicated as a human pathogen. It is infrequently recovered from clinical specimens probably because of inadequate processing of non-fermenting oxidase positive Gram negative bacilli. We present here a case of a 30 year old male suffering from right lung adenocarcinoma (moderately differentiated with multiple abdominal lymph node metastasis with Syringohydromyelia whose blood culture yielded Oligella ureolytica in pure culture. Oligella ureolytica isolation in pure culture and the patient′s response to targeted treatment supported that Oligella ureolytica was the true causative agent of the blood stream infection. Early suspicion, diagnosis and treatment with potent antibiotics are needed to prevent further complications resulting from infection with this emerging pathogen.

CO2 Selective, Zeolitic Imidazolate Framework-7 Based Polymer Composite Mixed-Matrix Membranes

KAUST Repository

Chakrabarty, Tina; Neelakanda, Pradeep; Peinemann, Klaus-Viktor

2018-01-01

CO2 removal is necessary to mitigate the effects of global warming but it is a challenging process to separate CO2 from natural gas, biogas, and other gas streams. Development of hybrid membranes by use of polymers and metal-organic framework (MOF) particles is a viable option to overcome this challenge. A ZIF-7 nano-filler that was synthesized in our lab was embedded into a designed polymer matrix at various loadings and the performance of the mixed matrix membranes was evaluated in terms of gas permeance and selectivity. Hybrid membranes with various loadings (20, 30 and 40 wt%) were developed and tested at room temperature by a custom made time lag equipment and a jump in selectivity was observed when compared with the pristine polymer. A commercially attractive region for the selectivity CO2 over CH4 was achieved with a selectivity of 39 for 40 wt% particle loading. An increase in selectivity was observed with the increase of ZIF-7 loadings. Best performance was seen at 40% ZIF-7 loaded membrane with an ideal selectivity of 39 for CO2 over CH4. The obtained selectivity was 105% higher for CO2 over CH4 than the selectivity of the pristine polymer with a slight decrease in permeance. Morphological characterization of such developed membranes showed an excellent compatibility between the polymer and particle adhesion.

CO2 Selective, Zeolitic Imidazolate Framework-7 Based Polymer Composite Mixed-Matrix Membranes

KAUST Repository

Chakrabarty, Tina

2018-05-17

CO2 removal is necessary to mitigate the effects of global warming but it is a challenging process to separate CO2 from natural gas, biogas, and other gas streams. Development of hybrid membranes by use of polymers and metal-organic framework (MOF) particles is a viable option to overcome this challenge. A ZIF-7 nano-filler that was synthesized in our lab was embedded into a designed polymer matrix at various loadings and the performance of the mixed matrix membranes was evaluated in terms of gas permeance and selectivity. Hybrid membranes with various loadings (20, 30 and 40 wt%) were developed and tested at room temperature by a custom made time lag equipment and a jump in selectivity was observed when compared with the pristine polymer. A commercially attractive region for the selectivity CO2 over CH4 was achieved with a selectivity of 39 for 40 wt% particle loading. An increase in selectivity was observed with the increase of ZIF-7 loadings. Best performance was seen at 40% ZIF-7 loaded membrane with an ideal selectivity of 39 for CO2 over CH4. The obtained selectivity was 105% higher for CO2 over CH4 than the selectivity of the pristine polymer with a slight decrease in permeance. Morphological characterization of such developed membranes showed an excellent compatibility between the polymer and particle adhesion.

StreamCat

Data.gov (United States)

U.S. Environmental Protection Agency — The StreamCat Dataset provides summaries of natural and anthropogenic landscape features for ~2.65 million streams, and their associated catchments, within the...

Stream Crossings

Data.gov (United States)

Vermont Center for Geographic Information — Physical measurements and attributes of stream crossing structures and adjacent stream reaches which are used to provide a relative rating of aquatic organism...

Improved antifouling properties of polymer membranes using a ‘layer-by-layer’ mediated method

KAUST Repository

Chen, Lin

2013-01-01

Polymeric reverse osmosis membranes were modified with antifouling polymer brushes through a \\'layer by layer\\' (LBL) mediated method. Based on pure physical electrostatic interaction, the attachment of LBL films did not alter separation performance of the membranes. In addition, the incorporation of an LBL film also helped to amplify the number of potential reaction sites on the membrane surfaces for attachment of antifouling polymer brushes, which were then attached to the surface. Attachment of the brushes included two different approaches, grafting to and grafting from. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements showed successful growth of the LBL films and subsequently the polymer brushes. Using this method to modify reverse osmosis membranes, preliminary performance testing showed the antifouling properties of the as-modified membranes were much better than the virgin membrane with no significant loss in water flux and salt rejection. © 2013 The Royal Society of Chemistry.

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

Energy Technology Data Exchange (ETDEWEB)

Bergemann, Claudia [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Cornelsen, Matthias [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Quade, Antje [Leibniz-Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany); Laube, Thorsten; Schnabelrauch, Matthias [INNOVENT e.V., Biomaterials Department, Pruessingstrasse 27B, D-07745 Jena (Germany); Rebl, Henrike [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Weißmann, Volker [Institute for Polymer Technologies (IPT) e.V., Alter Holzhafen 19, D-23966 Wismar (Germany); Seitz, Hermann [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Nebe, Barbara, E-mail: barbara.nebe@med.uni-rostock.de [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany)

2016-02-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds.

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

International Nuclear Information System (INIS)

Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

2016-01-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds

Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix

Science.gov (United States)

Porras, R.; Bavykin, D. V.; Zekonyte, J.; Walsh, F. C.; Wood, R. J.

2016-05-01

Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the ‘drop-cast’ method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young’s modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young’s modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM.

A comparative study on electrochemical co-deposition and capacitance of composite films of conducting polymers and carbon nanotubes

International Nuclear Information System (INIS)

Peng Chuang; Jin Jun; Chen, George Z.

2007-01-01

Composite films of carbon nanotubes (CNTs) with polyaniline (PANI), polypyrrole (PPY) or poly[3,4-ethylenedioxythiophene] (PEDOT) were prepared via electrochemical co-deposition from solutions containing acid treated CNTs and the corresponding monomer. In the cases of PPY and PEDOT, CNTs served as the charge carriers during electro-deposition, and also acted as both the backbone of a three-dimensional micro- and nano-porous structure and the effective charge-balancing dopant within the polymer. All the composites showed improved mechanical integrity, higher electronic and ionic conductivity (even when the polymer was reduced), and exhibited larger electrode specific capacitance than the polymer alone. Under similar conditions, the capacitance was enhanced significantly in as-prepared PPY-CNT and PEDOT-CNT films. However, the fresh PANI-CNT film was electrochemically similar to PANI, but PPY-CNT and PEDOT-CNT differed noticeably from the respective polymers alone. In continuous potential cycling tests, unlike the pure polymer and other composite films, PANI-CNT performed much better in retaining the capacitance of the as-prepared film, and the possible cause is analysed

Thin HTSC films produced by a polymer metal precursor technique

Science.gov (United States)

Lampe, L. v.; Zygalsky, F.; Hinrichsen, G.

In precursors the metal ions are combined with acid groups of polymethacrylic acid (PMAA), polyacrylic acid (PAA) or novolac. Compared to thermal degradation temperature of pure polymers those of precursors are low. Precursors films were patterned by UV lithography. Diffractometric investigations showed that the c-axis oriented epitaxial films of YBa 2Cu 3O x and Bi 2Sr 2CaCu 2O x originated from amorphous metal oxide films, which were received after thermal degradation of the precursor. Transition temperatures and current densities were determined by electric resistivity measurements.

Analysis of pure maple syrup consumers

Science.gov (United States)

Paul E. Sendak

1974-01-01

Virtually all of the pure maple syrup productim in the United States is in the northern states of Maine, Massachusetts, Michigan, New Hampshire, New York, Ohio, Pennsylvania, Vermont, and Wisconsin. Pure maple syrup users living in the maple production area and users living in other areas of the United States were asked a series of questions about their use of pure...

Mechanical properties of polymer-infiltrated-ceramic-network materials.

Science.gov (United States)

Coldea, Andrea; Swain, Michael V; Thiel, Norbert

2013-04-01

To determine and identify correlations between flexural strength, strain at failure, elastic modulus and hardness versus ceramic network densities of a range of novel polymer-infiltrated-ceramic-network (PICN) materials. Four ceramic network densities ranging from 59% to 72% of theoretical density, resin infiltrated PICN as well as pure polymer and dense ceramic cross-sections were subjected to Vickers Indentations (HV 5) for hardness evaluation. The flexural strength and elastic modulus were measured using three-point-bending. The fracture response of PICNs was determined for cracks induced by Vickers-indentation. Optical and scanning electron microscopy (SEM) was employed to observe the indented areas. Depending on the density of the porous ceramic the flexural strength of PICNs ranged from 131 to 160MPa, the hardness values ranged between 1.05 and 2.10GPa and the elastic modulus between 16.4 and 28.1GPa. SEM observations of the indentation induced cracks indicate that the polymer network causes greater crack deflection than the dense ceramic material. The results were compared with simple analytical expressions for property variation of two phase composite materials. This study points out the correlation between ceramic network density, elastic modulus and hardness of PICNs. These materials are considered to more closely imitate natural tooth properties compared with existing dental restorative materials. Copyright © 2013 Academy of Dental Materials. All rights reserved.

Prioritized Contact Transport Stream

Science.gov (United States)

Hunt, Walter Lee, Jr. (Inventor)

2015-01-01

A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

Re-Meandering of Lowland Streams

DEFF Research Database (Denmark)

Pedersen, Morten Lauge; Kristensen, Klaus Kevin; Friberg, Nikolai

2014-01-01

We evaluated the restoration of physical habitats and its influence on macroinvertebrate community structure in 18 Danish lowland streams comprising six restored streams, six streams with little physical alteration and six channelized streams. We hypothesized that physical habitats...... and macroinvertebrate communities of restored streams would resemble those of natural streams, while those of the channelized streams would differ from both restored and near-natural streams. Physical habitats were surveyed for substrate composition, depth, width and current velocity. Macroinvertebrates were sampled...... along 100 m reaches in each stream, in edge habitats and in riffle/run habitats located in the center of the stream. Restoration significantly altered the physical conditions and affected the interactions between stream habitat heterogeneity and macroinvertebrate diversity. The substrate in the restored...

A predictive group-contribution simplified PC-SAFT equation of state: Application to polymer systems

DEFF Research Database (Denmark)

Tihic, Amra; Kontogeorgis, Georgios; von Solms, Nicolas

2008-01-01

A group-contribution (GC) method is coupled with the molecular-based perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) to predict its characteristic pure compound parameters. The estimation of group contributions for the parameters is based on a parameter...... are the molecular structure of the polymer of interest in terms of functional groups and a single binary interaction parameter for accurate mixture calculations....

StreamExplorer: A Multi-Stage System for Visually Exploring Events in Social Streams.

Science.gov (United States)

Wu, Yingcai; Chen, Zhutian; Sun, Guodao; Xie, Xiao; Cao, Nan; Liu, Shixia; Cui, Weiwei

2017-10-18

Analyzing social streams is important for many applications, such as crisis management. However, the considerable diversity, increasing volume, and high dynamics of social streams of large events continue to be significant challenges that must be overcome to ensure effective exploration. We propose a novel framework by which to handle complex social streams on a budget PC. This framework features two components: 1) an online method to detect important time periods (i.e., subevents), and 2) a tailored GPU-assisted Self-Organizing Map (SOM) method, which clusters the tweets of subevents stably and efficiently. Based on the framework, we present StreamExplorer to facilitate the visual analysis, tracking, and comparison of a social stream at three levels. At a macroscopic level, StreamExplorer uses a new glyph-based timeline visualization, which presents a quick multi-faceted overview of the ebb and flow of a social stream. At a mesoscopic level, a map visualization is employed to visually summarize the social stream from either a topical or geographical aspect. At a microscopic level, users can employ interactive lenses to visually examine and explore the social stream from different perspectives. Two case studies and a task-based evaluation are used to demonstrate the effectiveness and usefulness of StreamExplorer.Analyzing social streams is important for many applications, such as crisis management. However, the considerable diversity, increasing volume, and high dynamics of social streams of large events continue to be significant challenges that must be overcome to ensure effective exploration. We propose a novel framework by which to handle complex social streams on a budget PC. This framework features two components: 1) an online method to detect important time periods (i.e., subevents), and 2) a tailored GPU-assisted Self-Organizing Map (SOM) method, which clusters the tweets of subevents stably and efficiently. Based on the framework, we present Stream

Star-Branched Polymers (Star Polymers)

KAUST Repository

Hirao, Akira

2015-09-01

The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

An investigation of reaction parameters on geochemical storage of non-pure CO2 streams in iron oxides-bearing formations

Energy Technology Data Exchange (ETDEWEB)

Garcia, Susana; Liu, Q.; Bacon, Diana H.; Maroto-Valer, M. M.

2014-08-26

Hematite deposit that is the main FeIII-bearing mineral in sedimentary red beds was proposed as a potential host repository for converting CO2 into carbonate minerals such as siderite (FeCO3), when CO2–SO2 gas mixtures are co-injected. This work investigated CO2 mineral trapping using hematite and sensitivity of the reactive systems to different parameters, including particle size, gas composition, temperature, pressure, and solid-to-liquid ratio. Experimental and modelling studies of hydrothermal experiments were conducted, which emulated a CO2 sequestration scenario by injecting CO2-SO2 gas streams into a NaCl-NaOH brine hosted in iron oxide-containing aquifer. This study provides novel information on the mineralogical changes and fluid chemistry derived from the co-injection of CO2-SO2 gas mixtures in hematite deposit. It can be concluded that the amount of siderite precipitate depends primarily on the SO2 content of the gas stream. Increasing SO2 content in the system could promote the reduction of Fe3+ from the hematite sample to Fe2+, which will be further available for its precipitation as siderite. Moreover, siderite precipitation is enhanced at low temperatures and high pressures. The influence of the solid to liquid ratio on the overall carbonation reaction suggests that the conversion increases if the system becomes more diluted.

Polymer nanocomposites: polymer and particle dynamics

KAUST Repository

Kim, Daniel; Srivastava, Samanvaya; Narayanan, Suresh; Archer, Lynden A.

2012-01-01

Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has

X-ray studies of the liquid/vapor interface: Water and polymer and fatty acid monolayers on water

International Nuclear Information System (INIS)

Schlossman, M.L.; Schwartz, D.K.; Kawamoto, E.H.; Kellogg, G.J.; Pershan, P.S.; Ocko, B.M.; Kim, M.W.; Chung, T.C.

1989-01-01

X-ray specular reflectivity is used to study the liquid-vapor interface of pure water and of fatty acid and polymer monolayers at that interface. For the pure water surface the reflectivity was measured for three different spectrometer resolutions and simultaneous fits with only one free parameter to all of the data are in excellent agreement with the prediction of capillary wave theory for the RMS surface roughness. Diffuse scattering away from the specular condition, at wavevectors corresponding to those of the capillary waves, yields intensities and line shapes in agreement with theory with no significant adjustable parameters. Reflectivity from separate monolayers of co-poly 1, 2-butadiene/butyl alcohol (50% random substitution) and lignoceric acid (CH 3 (CH 2 ) 22 COOH) at the water/vapor interface are interpreted to obtain profiles of the average electron density ρ(z) as a function of distance z along the surface normal. For the polymer monolayer we find the following: (1) a local maximum in the electron density approximately 10% larger than that of the bulk polymer and (2) the RMS roughness of the vapor/polymer interface agrees with capillary wave theory predictions for the lower surface pressures. For the highest surface pressure the RMS roughness exceeds the value predicted by the capillary wave model. Measurements of reflectivity from a lignoceric acid monolayer, as a function of surface pressure throughout an isotherm (near room temperature), reveal the following behavior: (1) the overall thickness of the monolayer increases with increasing pressure and (2) the head groups occupy a progressively larger region along the surface normal as the pressure increases, indicating that they rearrange normal to the interface. 15 refs., 5 figs., 2 tabs

Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

National Research Council Canada - National Science Library

Zhang, Xuejun, Ph.D

1999-01-01

Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

Enhanced dissolution and oral bioavailability of valsartan solid dispersions prepared by a freeze-drying technique using hydrophilic polymers.

Science.gov (United States)

Xu, Wei-Juan; Xie, Hong-Juan; Cao, Qing-Ri; Shi, Li-Li; Cao, Yue; Zhu, Xiao-Yin; Cui, Jing-Hao

2016-01-01

This study aimed to improve the dissolution rate and oral bioavailability of valsartan (VAL), a poorly soluble drug using solid dispersions (SDs). The SDs were prepared by a freeze-drying technique with polyethylene glycol 6000 (PEG6000) and hydroxypropylmethylcellulose (HPMC 100KV) as hydrophilic polymers, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 as a surfactant without using any organic solvents. In vitro dissolution rate and physicochemical properties of the SDs were characterized using the USP paddle method, differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and Fourier transform-infrared (FT-IR) spectroscopy, respectively. In addition, the oral bioavailability of SDs in rats was evaluated by using VAL (pure drug) as a reference. The dissolution rates of the SDs were significantly improved at pH 1.2 and pH 6.8 compared to those of the pure drug. The results from DSC, XRD showed that VAL was molecularly dispersed in the SDs as an amorphous form. The FT-IR results suggested that intermolecular hydrogen bonding had formed between VAL and its carriers. The SDs exhibited significantly higher values of AUC 0-24 h and Cmax in comparison with the pure drug. In conclusion, hydrophilic polymer-based SDs prepared by a freeze-drying technique can be a promising method to enhance dissolution rate and oral bioavailability of VAL.

Pilot-Streaming: Design Considerations for a Stream Processing Framework for High-Performance Computing

OpenAIRE

Andre Luckow; Peter Kasson; Shantenu Jha

2016-01-01

This White Paper (submitted to STREAM 2016) identifies an approach to integrate streaming data with HPC resources. The paper outlines the design of Pilot-Streaming, which extends the concept of Pilot-abstraction to streaming real-time data.

Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid

Energy Technology Data Exchange (ETDEWEB)

Varaprasad, Kokkarachedu, E-mail: varmaindian@gmail.com [Centro de Investigación de Polímeros Avanzados (CIPA), Avenida Collao 1202, Edificio de Laboratorios, Concepción (Chile); Pariguana, Manuel [Centro de Investigación de Polímeros Avanzados (CIPA), Avenida Collao 1202, Edificio de Laboratorios, Concepción (Chile); Centro de Innovación Tecnológica Agroindustrial CITE Agroindustrial, Panamericana Sur Km, 293.3, Ica (Peru); Raghavendra, Gownolla Malegowd [Department of Packaging, Yonsei University, Wonju, Gangwon-do 220 710 (Korea, Republic of); Jayaramudu, Tippabattini [Center for Nano Cellulose Future Composites, Department of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Ku, Incheon 402–751 (Korea, Republic of); Sadiku, Emmanuel Rotimi [Department of Polymer Technology, Tshwane University of Technology, CSIR-Campus, Pretoria 0040 (South Africa)

2017-01-01

The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications. - Graphical abstract: Biodegradable metal-oxide/polymer nanocomposites films prepared by using poly-ε-caprolactone with disposed PET oil bottles terephthalic acid monomer. The development of biodegradable film provides a new material with desirable mechanical, physical and chemical properties and can be utilized for industrial applications. - Highlights: • Terephthalic acid obtained from disposed PET oil bottles via precipitation technique. • New nano metal-oxides were developed by double precipitation technique. • Nano metal-oxide polymer films were synthesized by solvent evaporation method. • Nano metal-oxide polymer films exhibit superior mechanical characteristics.

Fundamentals of the Pure Spinor Formalism

CERN Document Server

Hoogeveen, Joost

2010-01-01

This thesis presents recent developments within the pure spinor formalism, which has simplified amplitude computations in perturbative string theory, especially when spacetime fermions are involved. Firstly the worldsheet action of both the minimal and the non-minimal pure spinor formalism is derived from first principles, i.e. from an action with two dimensional diffeomorphism and Weyl invariance. Secondly the decoupling of unphysical states in the minimal pure spinor formalism is proved

Introduction to stream: An Extensible Framework for Data Stream Clustering Research with R

Directory of Open Access Journals (Sweden)

Michael Hahsler

2017-02-01

Full Text Available In recent years, data streams have become an increasingly important area of research for the computer science, database and statistics communities. Data streams are ordered and potentially unbounded sequences of data points created by a typically non-stationary data generating process. Common data mining tasks associated with data streams include clustering, classification and frequent pattern mining. New algorithms for these types of data are proposed regularly and it is important to evaluate them thoroughly under standardized conditions. In this paper we introduce stream, a research tool that includes modeling and simulating data streams as well as an extensible framework for implementing, interfacing and experimenting with algorithms for various data stream mining tasks. The main advantage of stream is that it seamlessly integrates with the large existing infrastructure provided by R. In addition to data handling, plotting and easy scripting capabilities, R also provides many existing algorithms and enables users to interface code written in many programming languages popular among data mining researchers (e.g., C/C++, Java and Python. In this paper we describe the architecture of stream and focus on its use for data stream clustering research. stream was implemented with extensibility in mind and will be extended in the future to cover additional data stream mining tasks like classification and frequent pattern mining.

Comparative in vitro biocompatibility of nickel-titanium, pure nickel, pure titanium, and stainless steel: genotoxicity and atomic absorption evaluation.

Science.gov (United States)

Assad, M; Lemieux, N; Rivard, C H; Yahia, L H

1999-01-01

The genotoxicity level of nickel-titanium (NiTi) was compared to that of its pure constituents, pure nickel (Ni) and pure titanium (Ti) powders, and also to 316L stainless steel (316L SS) as clinical reference material. In order to do so, a dynamic in vitro semiphysiological extraction was performed with all metals using agitation and ISO requirements. Peripheral blood lymphocytes were then cultured in the presence of all material extracts, and their comparative genotoxicity levels were assessed using electron microscopy-in situ end-labeling (EM-ISEL) coupled to immunogold staining. Cellular chromatin exposition to pure Ni and 316L SS demonstrated a significantly stronger gold binding than exposition to NiTi, pure Ti, or the untreated control. In parallel, graphite furnace atomic absorption spectrophotometry (AAS) was also performed on all extraction media. The release of Ni atoms took the following decreasing distribution for the different resulting semiphysiological solutions: pure Ni, 316L SS, NiTi, Ti, and controls. Ti elements were detected after elution of pure titanium only. Both pure titanium and nickel-titanium specimens obtained a relative in vitro biocompatibility. Therefore, this quantitative in vitro study provides optimistic results for the eventual use of nickel-titanium alloys as surgical implant materials.

Benthic invertebrate fauna, small streams

Science.gov (United States)

J. Bruce Wallace; S.L. Eggert

2009-01-01

Small streams (first- through third-order streams) make up >98% of the total number of stream segments and >86% of stream length in many drainage networks. Small streams occur over a wide array of climates, geology, and biomes, which influence temperature, hydrologic regimes, water chemistry, light, substrate, stream permanence, a basin's terrestrial plant...

Electroluminescent Characteristics of DBPPV–ZnO Nanocomposite Polymer Light Emitting Devices

Directory of Open Access Journals (Sweden)

Madhava Rao MV

2009-01-01

Full Text Available Abstract We have demonstrated that fabrication and characterization of nanocomposite polymer light emitting devices with metal Zinc Oxide (ZnO nanoparticles and 2,3-dibutoxy-1,4-poly(phenylenevinylene (DBPPV. The current and luminance characteristics of devices with ZnO nanoparticles are much better than those of device with pure DBPPV. Optimized maximum luminance efficiencies of DBPPV–ZnO (3:1 wt% before annealing (1.78 cd/A and after annealing (2.45 cd/A having a brightness 643 and 776 cd/m2at a current density of 36.16 and 31.67 mA/cm2are observed, respectively. Current density–voltage and brightness–voltage characteristics indicate that addition of ZnO nanoparticles can facilitate electrical injection and charge transport. The thermal annealing is thought to result in the formation of an interfacial layer between emissive polymer film and cathode.

Estimated vapor pressure for WTP process streams

Energy Technology Data Exchange (ETDEWEB)

Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-01-01

Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

Concurrence classes for general pure multipartite states

International Nuclear Information System (INIS)

Heydari, Hoshang

2005-01-01

We propose concurrence classes for general pure multipartite states based on an orthogonal complement of a positive operator-valued measure on quantum phase. In particular, we construct W m class, GHZ m , and GHZ m-1 class concurrences for general pure m-partite states. We give explicit expressions for W 3 and GHZ 3 class concurrences for general pure three-partite states and for W 4 , GHZ 4 and GHZ 3 class concurrences for general pure four-partite states

Inventory of miscellaneous streams

International Nuclear Information System (INIS)

Lueck, K.J.

1995-09-01

On December 23, 1991, the US Department of Energy, Richland Operations Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order. The Consent Order lists the regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code. The RL provided the US Congress a Plan and Schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site. The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the streams into two phases. The Phase 1 streams were considered to be higher priority than the Phase 2 streams. The actions recommended for the Phase 1 and 2 streams in the two reports were incorporated in the Hanford Federal Facility Agreement and Consent Order. Miscellaneous Streams are those liquid effluents streams identified within the Consent Order that are discharged to the ground but are not categorized as Phase 1 or Phase 2 Streams. This document consists of an inventory of the liquid effluent streams being discharged into the Hanford soil column

Polymer electronics

CERN Document Server

Hsin-Fei, Meng

2013-01-01

Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

Quality control in the recycling stream of PVC from window frames by hyperspectral imaging

Science.gov (United States)

Luciani, Valentina; Serranti, Silvia; Bonifazi, Giuseppe; Di Maio, Francesco; Rem, Peter

2013-05-01

Polyvinyl chloride (PVC) is one of the most commonly used thermoplastic materials in respect to the worldwide polymer consumption. PVC is mainly used in the building and construction sector, products such as pipes, window frames, cable insulation, floors, coverings, roofing sheets, etc. are realised utilising this material. In recent years, the problem of PVC waste disposal gained increasing importance in the public discussion. The quantity of used PVC items entering the waste stream is gradually increased as progressively greater numbers of PVC products approach to the end of their useful economic lives. The quality of the recycled PVC depends on the characteristics of the recycling process and the quality of the input waste. Not all PVC-containing waste streams have the same economic value. A transparent relation between value and composition is required to decide if the recycling process is cost effective for a particular waste stream. An objective and reliable quality control technique is needed in the recycling industry for the monitoring of both recycled flow streams and final products in the plant. In this work hyperspectral imaging technique in the near infrared (NIR) range (1000-1700 nm) was applied to identify unwanted plastic contaminants and rubber present in PVC coming from windows frame waste in order to assess a quality control procedure during its recycling process. Results showed as PVC, PE and rubber can be identified adopting the NIR-HSI approach.

Time-Based Data Streams: Fundamental Concepts for a Data Resource for Streams

Energy Technology Data Exchange (ETDEWEB)

Beth A. Plale

2009-10-10

Real time data, which we call data streams, are readings from instruments, environmental, bodily or building sensors that are generated at regular intervals and often, due to their volume, need to be processed in real time. Often a single pass is all that can be made on the data, and a decision to discard or keep the instance is made on the spot. Too, the stream is for all practical purposes indefinite, so decisions must be made on incomplete knowledge. This notion of data streams has a different set of issues from a file, for instance, that is byte streamed to a reader. The file is finite, so the byte stream is becomes a processing convenience more than a fundamentally different kind of data. Through the duration of the project we examined three aspects of streaming data: the first, techniques to handle streaming data in a distributed system organized as a collection of web services, the second, the notion of the dashboard and real time controllable analysis constructs in the context of the Fermi Tevatron Beam Position Monitor, and third and finally, we examined provenance collection of stream processing such as might occur as raw observational data flows from the source and undergoes correction, cleaning, and quality control. The impact of this work is severalfold. We were one of the first to advocate that streams had little value unless aggregated, and that notion is now gaining general acceptance. We were one of the first groups to grapple with the notion of provenance of stream data also.

Biodegradable Polymers

OpenAIRE

Vroman, Isabelle; Tighzert, Lan

2009-01-01

Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

Asteroid/meteorite streams

Science.gov (United States)

Drummond, J.

The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential

Field effect measurements on charge carrier mobilities in various polymer-fullerene blend compositions

International Nuclear Information System (INIS)

Hauff, Elizabeth von; Parisi, Juergen; Dyakonov, Vladimir

2006-01-01

In this study we investigated materials typically used in polymer photovoltaics. Field effect measurements were performed in order to determine the hole mobilities in the conjugated polymer poly(3-hexylthiophene) (P3HT) and the electron mobilities in the methanofullerene[6,6]-phenyl C 61 -butyric acid methyl ester (PCBM), and, particularly, in the polymer-fullerene composite blends. Regarding the pure films, electron mobilities in PCBM were found to be in the 10 -2 cm 2 /Vs range, and hole mobilities in P3HT were found to be in the 10 -3 cm2/Vs range. In the PCBM:P3HT blends, it was found that varying the PCBM content in PCBM:P3HT blends led to a steep increase in electron mobility with increasing PCBM content, while the hole mobility was found to slightly decrease with the increasing PCBM concentration. In 2:1 PCBM:P3HT tempered blends, the charge carrier mobilities were found to be roughly balanced, at 10 -3 cm 2 /Vs. For improved electron transport in the blends, tempering was found to be crucial

Upper-hybrid solitons and oscillating-two-stream instabilities

International Nuclear Information System (INIS)

Porkolab, M.; Goldman, M.V.

1976-01-01

A warm two-fluid theory of soliton formation near the upper-hybrid frequency is developed. Several forms of the nonlinear Schrodinger equation are obtained, depending on whether the electric field is completely perpendicular to the dc magnetic field or whether it has an additional small component parallel to the magnetic field. For the perpendicular case, the character of the soliton depends on its scale length, L, and on β. For low β, when L c/ω/subp//subi/ the super-Alvenic solitons described magnetohydromagnetically by Kaufman and Stenflo are obtained. However, the case E/sub parallel/not-equal0 may be of more interest, since it couples the pump to the excited waves more efficiently. In the limit of linearization about an infinite wavelength pump, the nonlinear Schrodinger equations yield purely growing (oscillating-two-stream) instabilities in both cases

Micro- and nanostructured electro-active polymer actuators as smart muscles for incontinence treatment

International Nuclear Information System (INIS)

Osmani, Bekim; Töpper, Tino; Weiss, Florian M.; Leung, Vanessa; Müller, Bert; Deschenaux, Christian; Nohava, Jiri

2015-01-01

Treatments of severe incontinence are currently based on purely mechanical systems that generally result in revision after three to five years. Our goal is to develop a prototype acting in a natural-analogue manner as artificial muscle, which is based on electro-active polymers. Dielectric actuators have outstanding performances including millisecond response times, mechanical strains of more than 10 % and power to mass densities similar to natural muscles. They basically consist of polymer films sandwiched between two compliant electrodes. The incompressible but elastic polymer film transduces the electrical energy into mechanical work according to the Maxwell pressure. Available polymer films are micrometers thick and voltages as large as kV are necessary to obtain 10 % strain. For medical implants, polymer films should be nanometer thin to realize actuation below 48 V. The metallic electrodes have to be stretchable to follow the strain of 10 % and remain conductive. Recent results on the stress/strain behavior of anisotropic EAP-cantilevers have shown dependencies on metal electrode preparation. We have investigated tunable anisotropic micro- and nanostructures for metallic electrodes. They show a preferred actuation direction with improved stress-strain behavior. The bending of the cantilever has been characterized by the laser beam deflection method. The impact of the electrode on the effective Young's Modulus is measured using an Ultra Nanoindentation Tester with an integrated reference system for soft polymer surfaces. Once ten thousand layers of nanometer-thin EAP actuators are available, devices beyond the envisioned application will flood the market

Micro- and nanostructured electro-active polymer actuators as smart muscles for incontinence treatment

Energy Technology Data Exchange (ETDEWEB)

Osmani, Bekim, E-mail: bekim.osmani@unibas.ch, E-mail: tino.toepper@unibas.ch; Töpper, Tino, E-mail: bekim.osmani@unibas.ch, E-mail: tino.toepper@unibas.ch; Weiss, Florian M., E-mail: vanessa.leung@unibas.ch, E-mail: bert.mueller@unibas.ch; Leung, Vanessa, E-mail: vanessa.leung@unibas.ch, E-mail: bert.mueller@unibas.ch; Müller, Bert, E-mail: vanessa.leung@unibas.ch, E-mail: bert.mueller@unibas.ch [Biomaterials Science Center, University of Basel, c/o University Hospital, 4031 Basel (Switzerland); Deschenaux, Christian, E-mail: jiri.nohava@anton-paar.com; Nohava, Jiri, E-mail: jiri.nohava@anton-paar.com [Anton Paar TriTec SA, Rue de la Gare 4, Galileo Center, 2034 Peseux (Switzerland)

2015-02-17

Treatments of severe incontinence are currently based on purely mechanical systems that generally result in revision after three to five years. Our goal is to develop a prototype acting in a natural-analogue manner as artificial muscle, which is based on electro-active polymers. Dielectric actuators have outstanding performances including millisecond response times, mechanical strains of more than 10 % and power to mass densities similar to natural muscles. They basically consist of polymer films sandwiched between two compliant electrodes. The incompressible but elastic polymer film transduces the electrical energy into mechanical work according to the Maxwell pressure. Available polymer films are micrometers thick and voltages as large as kV are necessary to obtain 10 % strain. For medical implants, polymer films should be nanometer thin to realize actuation below 48 V. The metallic electrodes have to be stretchable to follow the strain of 10 % and remain conductive. Recent results on the stress/strain behavior of anisotropic EAP-cantilevers have shown dependencies on metal electrode preparation. We have investigated tunable anisotropic micro- and nanostructures for metallic electrodes. They show a preferred actuation direction with improved stress-strain behavior. The bending of the cantilever has been characterized by the laser beam deflection method. The impact of the electrode on the effective Young's Modulus is measured using an Ultra Nanoindentation Tester with an integrated reference system for soft polymer surfaces. Once ten thousand layers of nanometer-thin EAP actuators are available, devices beyond the envisioned application will flood the market.

Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

Energy Technology Data Exchange (ETDEWEB)

Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

2010-07-01

This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

Polarized ensembles of random pure states

Science.gov (United States)

Deelan Cunden, Fabio; Facchi, Paolo; Florio, Giuseppe

2013-08-01

A new family of polarized ensembles of random pure states is presented. These ensembles are obtained by linear superposition of two random pure states with suitable distributions, and are quite manageable. We will use the obtained results for two purposes: on the one hand we will be able to derive an efficient strategy for sampling states from isopurity manifolds. On the other, we will characterize the deviation of a pure quantum state from separability under the influence of noise.

Aeroacoustics of Three-Stream Jets

Science.gov (United States)

Henderson, Brenda S.

2012-01-01

Results from acoustic measurements of noise radiated from a heated, three-stream, co-annular exhaust system operated at subsonic conditions are presented. The experiments were conducted for a range of core, bypass, and tertiary stream temperatures and pressures. The nozzle system had a fan-to-core area ratio of 2.92 and a tertiary-to-core area ratio of 0.96. The impact of introducing a third stream on the radiated noise for third-stream velocities below that of the bypass stream was to reduce high frequency noise levels at broadside and peak jet-noise angles. Mid-frequency noise radiation at aft observation angles was impacted by the conditions of the third stream. The core velocity had the greatest impact on peak noise levels and the bypass-to-core mass flow ratio had a slight impact on levels in the peak jet-noise direction. The third-stream jet conditions had no impact on peak noise levels. Introduction of a third jet stream in the presence of a simulated forward-flight stream limits the impact of the third stream on radiated noise. For equivalent ideal thrust conditions, two-stream and three-stream jets can produce similar acoustic spectra although high-frequency noise levels tend to be lower for the three-stream jet.

Academic Self-Concepts in Ability Streams: Considering Domain Specificity and Same-Stream Peers

Science.gov (United States)

Liem, Gregory Arief D.; McInerney, Dennis M.; Yeung, Alexander S.

2015-01-01

The study examined the relations between academic achievement and self-concepts in a sample of 1,067 seventh-grade students from 3 core ability streams in Singapore secondary education. Although between-stream differences in achievement were large, between-stream differences in academic self-concepts were negligible. Within each stream, levels of…

Polymer Crowding in Confined Polymer-Nanoparticle Mixtures

Science.gov (United States)

Davis, Wyatt J.; Denton, Alan R.

Crowding can influence the conformations and thus functionality of macromolecules in quasi-two-dimensional environments, such as DNA or proteins confined to a cell membrane. We explore such crowding within a model of polymers as penetrable ellipses, whose shapes are governed by the statistics of a 2D random walk. The principal radii of the polymers fluctuate according to probability distributions of the eigenvalues of the gyration tensor. Within this coarse-grained model, we perform Monte Carlo simulations of mixtures of polymers and hard nanodisks, including trial changes in polymer conformation (shape and orientation). Penetration of polymers by nanodisks is incorporated with a free energy cost predicted by polymer field theory. Over ranges of size ratio and nanodisk density, we analyze the influence of crowding on polymer shape by computing eigenvalue distributions, mean radius of gyration, and mean asphericity of the polymer. We compare results with predictions of free-volume theory and with corresponding results in three dimensions. Our approach may help to interpret recent (and motivate future) experimental studies of biopolymers interacting with cell membranes, with relevance for drug delivery and gene therapy. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

Solar wind stream interfaces

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1978-01-01

Measurements aboard Imp 6, 7, and 8 reveal that approximately one third of all high-speed solar wind streams observed at 1 AU contain a sharp boundary (of thickness less than approx.4 x 10 4 km) near their leading edge, called a stream interface, which separates plasma of distinctly different properties and origins. Identified as discontinuities across which the density drops abruptly, the proton temperature increases abruptly, and the speed rises, stream interfaces are remarkably similar in character from one stream to the next. A superposed epoch analysis of plasma data has been performed for 23 discontinuous stream interfaces observed during the interval March 1971 through August 1974. Among the results of this analysis are the following: (1) a stream interface separates what was originally thick (i.e., dense) slow gas from what was originally thin (i.e., rare) fast gas; (2) the interface is the site of a discontinuous shear in the solar wind flow in a frame of reference corotating with the sun; (3) stream interfaces occur at speeds less than 450 km s - 1 and close to or at the maximum of the pressure ridge at the leading edges of high-speed streams; (4) a discontinuous rise by approx.40% in electron temperature occurs at the interface; and (5) discontinuous changes (usually rises) in alpha particle abundance and flow speed relative to the protons occur at the interface. Stream interfaces do not generally recur on successive solar rotations, even though the streams in which they are embedded often do. At distances beyond several astronomical units, stream interfaces should be bounded by forward-reverse shock pairs; three of four reverse shocks observed at 1 AU during 1971--1974 were preceded within approx.1 day by stream interfaces. Our observations suggest that many streams close to the sun are bounded on all sides by large radial velocity shears separating rapidly expanding plasma from more slowly expanding plasma

Gelatin films plasticized with a simulated biodiesel coproduct stream

Directory of Open Access Journals (Sweden)

2009-04-01

Full Text Available In order to explore the possibility of substituting an unrefined biodiesel coproduct stream (BCS for refined glycerol as a polymer plasticizer we have prepared cast gelatin films plasticized with a simulated BCS, i.e., mixtures of glycerol and some of the typical components found in BCS (methyl linoleate, methyl oleate, linoleic acid, and oleic acid. We measured the tensile properties as a function of plasticizer composition, and analyzed the specific effect of each individual component on tensile properties. We found that it is the unrecovered alkyl esters that largely determine the tensile properties, and that BCS can be successfully used to plasticize cast gelatin films as long as the BCS contains 11 parts by weight, or less, of unrecovered alkyl esters per 100 parts glycerol.

Stream systems.

Science.gov (United States)

Jack E. Williams; Gordon H. Reeves

2006-01-01

Restored, high-quality streams provide innumerable benefits to society. In the Pacific Northwest, high-quality stream habitat often is associated with an abundance of salmonid fishes such as chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), and steelhead (O. mykiss). Many other native...

Evaluation of Influence of Various Polymers on Dissolution and Phase Behavior of Carbamazepine-Succinic Acid Cocrystal in Matrix Tablets

Directory of Open Access Journals (Sweden)

Majeed Ullah

2015-01-01

Full Text Available The aim of current study was to explore the influence of three commonly used polymers, that is, cellulosics and noncellulosics, for example, Methocel K4M, Kollidon VA/64, and Soluplus, on the phase disproportionation and drug release profile of carbamazepine-succinic acid (CBZ-SUC cocrystal at varying drug to polymer ratios (1 : 1 to 1 : 0.25 in matrix tablets. The polymorphic phase disproportionation during in-depth dissolution studies of CBZ-SUC cocrystals and its crystalline properties were scrutinized by X-ray powder diffractrometry and Raman spectroscopy. The percent drug release from HPMC formulations (CSH showed inverse relation with the concentration of polymer; that is, drug release increased with decrease in polymer concentration. On contrary, direct relation was observed between percent drug release and polymer concentrations of Kollidon VA 64/Soluplus (CSK, CSS. At similar polymer concentration, drug release from pure carbamazepine was slightly lower with HPMC formulations than that of cocrystal; however, opposite trend in release rate was observed with Kollidon VA/64 and Soluplus. The significant increase in dissolution rate of cocrystal occurred with Kollidon VA/64 and Soluplus at higher polymer concentration. Moreover, no phase change took place in Methocel and Kollidon formulations. No tablet residue was left for Soluplus formulation so the impact of polymer on cocrystal integrity cannot be predicted.

Evaluation of Influence of Various Polymers on Dissolution and Phase Behavior of Carbamazepine-Succinic Acid Cocrystal in Matrix Tablets

Science.gov (United States)

Ullah, Majeed; Ullah, Hanif; Mahmood, Qaisar; Hussain, Izhar

2015-01-01

The aim of current study was to explore the influence of three commonly used polymers, that is, cellulosics and noncellulosics, for example, Methocel K4M, Kollidon VA/64, and Soluplus, on the phase disproportionation and drug release profile of carbamazepine-succinic acid (CBZ-SUC) cocrystal at varying drug to polymer ratios (1 : 1 to 1 : 0.25) in matrix tablets. The polymorphic phase disproportionation during in-depth dissolution studies of CBZ-SUC cocrystals and its crystalline properties were scrutinized by X-ray powder diffractrometry and Raman spectroscopy. The percent drug release from HPMC formulations (CSH) showed inverse relation with the concentration of polymer; that is, drug release increased with decrease in polymer concentration. On contrary, direct relation was observed between percent drug release and polymer concentrations of Kollidon VA 64/Soluplus (CSK, CSS). At similar polymer concentration, drug release from pure carbamazepine was slightly lower with HPMC formulations than that of cocrystal; however, opposite trend in release rate was observed with Kollidon VA/64 and Soluplus. The significant increase in dissolution rate of cocrystal occurred with Kollidon VA/64 and Soluplus at higher polymer concentration. Moreover, no phase change took place in Methocel and Kollidon formulations. No tablet residue was left for Soluplus formulation so the impact of polymer on cocrystal integrity cannot be predicted. PMID:26380301

Micro- and Nanoprocessing of Polymers Using a Laser Plasma Extreme Ultraviolet Source

International Nuclear Information System (INIS)

Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; Rakowski, R.; Szczurek, A.; Szczurek, M.

2010-01-01

Laser plasma with temperature of the order of tens eV can be an efficient source of extreme ultraviolet (EUV). The radiation can be focused using different kind of optics, giving sufficient fluence for some applications. In this work we present results of investigations concerning applications of a laser plasma EUV source based on a double stream gas puff target. The source was equipped with two different grazing incidence collectors. One of them was a multifoil collector, the second one was an axisymmetrical ellipsoidal collector. The multifoil mirror was used mainly in experiments concerning micromachining of organic polymers by direct photo-etching. The experiments were performed for different polymers that were irradiated through a fine metal grid as a contact mask. The smallest element of a pattern structure obtained in this way was 5 μm, while the structure height was 50 μm giving an aspect ratio about 10. The laser-plasma EUV source equipped with the axisymmetrical ellipsoidal collector was used for surface modification of organic polymers and inorganic solids. The surface morphology after irradiation was investigated. Different forms of micro- and nanostructures were obtained depending on material and irradiation conditions. (author)

Polarized ensembles of random pure states

International Nuclear Information System (INIS)

Cunden, Fabio Deelan; Facchi, Paolo; Florio, Giuseppe

2013-01-01

A new family of polarized ensembles of random pure states is presented. These ensembles are obtained by linear superposition of two random pure states with suitable distributions, and are quite manageable. We will use the obtained results for two purposes: on the one hand we will be able to derive an efficient strategy for sampling states from isopurity manifolds. On the other, we will characterize the deviation of a pure quantum state from separability under the influence of noise. (paper)

Effect of disorder on exciton dissociation in conjugated polymers

International Nuclear Information System (INIS)

Feng Yuwen; Zhao Hui; Chen Yuguang; Yan Yonghong

2017-01-01

By using a multi-configurational time-dependent Hartree–Fock (MCTDHF) method for the time-dependent Schrödinger equation and a Newtonian equation of motion for lattice, we investigate the disorder effects on the dissociation process of excitons in conjugated polymer chains. The simulations are performed within the framework of an extended version of the Su–Schrieffer–Heeger model modified to include on-site disorder, off-diagonal, electron–electron interaction, and an external electric field. Our results show that Coulomb correlation effects play an important role in determining the exciton dissociation process. The electric field required to dissociate an exciton can practically impossibly occur in a pure polymer chain, especially in the case of triplet exciton. However, when the on-site disorder effects are taken into account, this leads to a reduction in mean dissociation electric fields. As the disorder strength increases, the dissociation field decreases effectively. On the contrary, the effects of off-diagonal disorder are negative in most cases. Moreover, the dependence of exciton dissociation on the conjugated length is also discussed. (paper)

PROXY-BASED PATCHING STREAM TRANSMISSION STRATEGY IN MOBILE STREAMING MEDIA SYSTEM

Institute of Scientific and Technical Information of China (English)

Liao Jianxin; Lei Zhengxiong; Ma Xutao; Zhu Xiaomin

2006-01-01

A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strategy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA) network. Performance of the whole system can be improved by using patching stream to transmit anterior part of the suffix that had been played back, and by batching all the demands for the suffix arrived in prefix period and patching stream transmission threshold period. Experimental results show that this strategy can efficiently reduce average network transmission cost and number of channels consumed in central streaming media server.

Development of polymer films by the coalescence of polymer particles in powdered and aqueous polymer-modified mortars

International Nuclear Information System (INIS)

Afridi, M.U.K.; Ohama, Y.; Demura, K.; Iqbal, M.Z.

2003-01-01

This paper evaluates and compares the coalescence of polymer particles (continuous polymer films formation) in powdered polymer-modified mortars (PPMMs) and aqueous polymer-modified mortars (APMMs). Polymer-modified mortars (PMMs) using various redispersible polymer powders (powdered cement modifiers) and polymer dispersions (aqueous cement modifiers) were prepared by varying the polymer-cement ratio (P/C) and were tested for the characterization of polymer films using a scanning electron microscope (SEM) after curing for 28 days. It is concluded from the test results that mortar constituents of unmodified mortar (UMM) are loosely joined with each other due to the absence of polymer films, thus having a structure with comparatively lower mechanical and durability characteristics. By contrast, mortar constituents in PPMMs and APMMs are compactly joined with each other due to the presence of interweaving polymer films, thereby forming a monolithic structure with improved mechanical and durability characteristics. However, the results make obvious the poor coalescence of polymer particles or development of inferior quality polymers films in PPMMs as compared to that observed in APMMs. Moreover, PPMMs show less uniform distribution of polymer films as compared to that in APMMs. Different powdered cement modifiers have different film-forming capabilities. However, such difference is hardly recognized in aqueous cement modifiers. The polymer films in PPMMs and APMMs may acquire different structures. They may appear as mesh-like, thread-like, rugged, dense or fibrous with fine or rough surfaces. Development of coherent polymer films is not well pronounced at a P/C of 5% in PPMMs, whereas sometimes coherent polymer films are observed at a P/C of 5% in APMMs. At a P/C of 10% or more, fully developed, coherent polymer films are observed in both PPMMs and APMMs

Transparent conductive ZnO layers on polymer substrates: Thin film deposition and application in organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Dosmailov, M. [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Leonat, L.N. [Linz Institute for Organic Solar Cells (LIOS)/Institute of Physical Chemistry, Johannes Kepler University Linz, A-4040 Linz (Austria); Patek, J. [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Roth, D.; Bauer, P. [Institute of Experimental Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Scharber, M.C.; Sariciftci, N.S. [Linz Institute for Organic Solar Cells (LIOS)/Institute of Physical Chemistry, Johannes Kepler University Linz, A-4040 Linz (Austria); Pedarnig, J.D., E-mail: johannes.pedarnig@jku.at [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria)

2015-09-30

Aluminum doped ZnO (AZO) and pure ZnO thin films are grown on polymer substrates by pulsed-laser deposition and the optical, electrical, and structural film properties are investigated. Laser fluence, substrate temperature, and oxygen pressure are varied to obtain transparent, conductive, and stoichiometric AZO layers on polyethylene terephthalate (PET) that are free of cracks. At low fluence (1 J/cm{sup 2}) and low pressure (10{sup −3} mbar), AZO/PET samples of high optical transmission in the visible range, low electrical sheet resistance, and high figure of merit (FOM) are produced. AZO films on fluorinated ethylene propylene have low FOM. The AZO films on PET substrates are used as electron transport layer in inverted organic solar cell devices employing P3HT:PCBM as photovoltaic polymer-fullerene bulk heterojunction. - Highlights: • Aluminum doped and pure ZnO thin films are grown on polyethylene terephthalate. • Growth parameters laser fluence, temperature, and gas pressure are optimized. • AZO films on PET have high optical transmission and electrical conductance (FOM). • Organic solar cells on PET using AZO as electron transport layer are made. • Power conversion efficiency of these OSC devices is measured.

Tensor modes in pure natural inflation

Science.gov (United States)

Nomura, Yasunori; Yamazaki, Masahito

2018-05-01

We study tensor modes in pure natural inflation [1], a recently-proposed inflationary model in which an axionic inflaton couples to pure Yang-Mills gauge fields. We find that the tensor-to-scalar ratio r is naturally bounded from below. This bound originates from the finiteness of the number of metastable branches of vacua in pure Yang-Mills theories. Details of the model can be probed by future cosmic microwave background experiments and improved lattice gauge theory calculations of the θ-angle dependence of the vacuum energy.

Method of producing vegetable puree

DEFF Research Database (Denmark)

2004-01-01

A process for producing a vegetable puree, comprising the sequential steps of: a)crushing, chopping or slicing the vegetable into pieces of 1 to 30 mm; b) blanching the vegetable pieces at a temperature of 60 to 90°C; c) contacted the blanched vegetable pieces with a macerating enzyme activity; d......) blending the macerated vegetable pieces and obtaining a puree....

Polymer films

Science.gov (United States)

Granick, Steve; Sukhishvili, Svetlana A.

2004-05-25

A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

Adsorption and flocculation by polymers and polymer mixtures.

Science.gov (United States)

Gregory, John; Barany, Sandor

2011-11-14

Polymers of various types are in widespread use as flocculants in several industries. In most cases, polymer adsorption is an essential prerequisite for flocculation and kinetic aspects are very important. The rates of polymer adsorption and of re-conformation (relaxation) of adsorbed chains are key factors that influence the performance of flocculants and their mode of action. Polyelectrolytes often tend to adopt a rather flat adsorbed configuration and in this state their action is mainly through charge effects, including 'electrostatic patch' attraction. When the relaxation rate is quite low, particle collisions may occur while the adsorbed chains are still in an extended state and flocculation by polymer bridging may occur. These effects are now well understood and supported by much experimental evidence. In recent years there has been considerable interest in the use of multi-component flocculants, especially dual-polymer systems. In the latter case, there can be significant advantages over the use of single polymers. Despite some complications, there is a broad understanding of the action of dual polymer systems. In many cases the sequence of addition of the polymers is important and the pre-adsorbed polymer can have two important effects: providing adsorption sites for the second polymer or causing a more extended adsorbed conformation as a result of 'site blocking'. Copyright © 2011 Elsevier B.V. All rights reserved.

Pure & crystallized 2D Boron Nitride sheets synthesized via a novel process coupling both PDCs and SPS methods

Science.gov (United States)

Yuan, Sheng; Linas, Sébastien; Journet, Catherine; Steyer, Philippe; Garnier, Vincent; Bonnefont, Guillaume; Brioude, Arnaud; Toury, Bérangère

2016-02-01

Within the context of emergent researches linked to graphene, it is well known that h-BN nanosheets (BNNSs), also referred as 2D BN, are considered as the best candidate for replacing SiO2 as dielectric support or capping layers for graphene. As a consequence, the development of a novel alternative source for highly crystallized h-BN crystals, suitable for a further exfoliation, is a prime scientific issue. This paper proposes a promising approach to synthesize pure and well-crystallized h-BN flakes, which can be easily exfoliated into BNNSs. This new accessible production process represents a relevant alternative source of supply in response to the increasing need of high quality BNNSs. The synthesis strategy to prepare pure h-BN is based on a unique combination of the Polymer Derived Ceramics (PDCs) route with the Spark Plasma Sintering (SPS) process. Through a multi-scale chemical and structural investigation, it is clearly shown that obtained flakes are large (up to 30 μm), defect-free and well crystallized, which are key-characteristics for a subsequent exfoliation into relevant BNNSs.

Inhibition of Protein Tyrosine Phosphatase 1B by Aurintricarboxylic Acid and Methylenedisalicylic Acid: Polymer versus Monomer

International Nuclear Information System (INIS)

Shrestha, Suja; Lee, Keun Hyeung; Cho, Hyeong Jin

2004-01-01

In this study, we examined whether the in vitro inhibitory activity of ATA against PTPases resides in the monomer or high molecular weight components. Not to mention commercial ATA, the ATA sample synthesized according to the method previously reported to produce monomer was also found to contain polymeric materials as described below. Therefore, monomeric component of ATA was prepared absolutely free of polymer. Also synthesized in a pure form was methylenedisalicylic acid (MDSA), one of the low molecular weight components formed in the conventional preparation of ATA. Commercial MDSA was also proved to contain polymeric substances. The inhibitory potency of ATA and MDSA synthesized in a polymer-free form was evaluated against human protein tyrosine phosphatase 1B (PTP1B). Commercial ATA, however, contains significant amounts of polymeric materials schematically represented as. In general, ATA is prepared by condensation of salicylic acid with formaldehyde and the branching reaction results in the formation of polymers of molecular weights up to several thousands Dalton

Investigation of tributyl phosphate hydrolysis in polymer matrix

International Nuclear Information System (INIS)

Sokal'skaya, L.I.; Yakshin, V.V.; Filippov, E.A.

1978-01-01

Hydrolytic stability of tributyl phosphate to 2 N nitric acid solutions at a temperature of 96 +- 0.5 deg C has been investigated. Tributyl phosphate has been put into a styrene - divinylbenzene matrix. By using the method of potentiometric titration in an anhydrous medium the following has been shown: the quantity of dibutylphosphoric acid that has been formed in the process of hydrolysis of tributylphosphate put into a polymeric matrix is two times smaller than that formed in the process of hydrolysis of pure tributylphosphate under the same conditions. The solubility of tributylphosphate put into a polymer matrix of 240 mg/l in distilled water and of 150 mg/l tributylphosphate in a sodaalkaline solution has been determined

Chemical stabilization of polymers: Implications for dermal exposure to additives.

Science.gov (United States)

Bartsch, N; Girard, M; Schneider, L; Weijgert, V Van De; Wilde, A; Kappenstein, O; Vieth, B; Hutzler, C; Luch, A

2018-04-16

Technical benefits of additives in polymers stand in marked contrast to their associated health risks. Here, a multi-analyte method based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was developed to quantify polymer additives in complex matrices such as low-density polyethylene (LDPE) and isolated human skin layers after dermal exposure ex vivo. That way both technical aspects and dermal exposure were investigated. The effects of polymer additivation on the material were studied using the example of LDPE. To this end, a tailor-made polymer was applied in aging studies that had been furnished with two different mixtures of phenol- and diarylamine-based antioxidants, plasticizers and processing aids. Upon accelerated thermo-oxidative aging of the material, the formation of LDPE degradation products was monitored with attenuated total reflectance-Fourier transformed infrared (ATR-FTIR) spectroscopy. Compared to pure LDPE, a protective effect of added antioxidants could be observed on the integrity of the polymer. Further, thermo-oxidative degradation of the additives and its kinetics were investigated using LDPE or squalane as matrix. The half-lives of additives in both matrices revealed significant differences between the tested additives as well as between LDPE and squalane. For instance, 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenol (Antioxidant 2246) showed a half-life 12 times lower when incorporated in LDPE as compared to squalane. As a model for dermal exposure of consumers, human skin was brought into contact with the tailor-made LDPE containing additives ex vivo in static Franz diffusion cells. The skin was then analyzed for additives and decomposition products. This study proved 10 polymer additives of diverse pysicochemical properties and functionalities to migrate out of the polymer and eventually overcome the intact human skin barrier during contact. Moreover, their individual distribution within

Evaluation of the streaming-matrix method for discrete-ordinates duct-streaming calculations

International Nuclear Information System (INIS)

Clark, B.A.; Urban, W.T.; Dudziak, D.J.

1983-01-01

A new deterministic streaming technique called the Streaming Matrix Hybrid Method (SMHM) is applied to two realistic duct-shielding problems. The results are compared to standard discrete-ordinates and Monte Carlo calculations. The SMHM shows promise as an alternative deterministic streaming method to standard discrete-ordinates

ActionScript Developer's Guide to PureMVC

CERN Document Server

Hall, Cliff

2011-01-01

Gain hands-on experience with PureMVC, the popular open source framework for developing maintainable applications with a Model-View-Controller architecture. In this concise guide, PureMVC creator Cliff Hall teaches the fundamentals of PureMVC development by walking you through the construction of a complete non-trivial Adobe AIR application. Through clear explanations and numerous ActionScript code examples, you'll learn best practices for using the framework's classes in your day-to-day work. Discover how PureMVC enables you to focus on the purpose and scope of your application, while the f

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

Energy Technology Data Exchange (ETDEWEB)

Lim, Wei Kang; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

2014-09-21

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

International Nuclear Information System (INIS)

Lim, Wei Kang; Denton, Alan R.

2014-01-01

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments

Crystal nuclei templated nanostructured membranes prepared by solvent crystallization and polymer migration

Science.gov (United States)

Wang, Bo; Ji, Jing; Li, Kang

2016-09-01

Currently, production of porous polymeric membranes for filtration is predominated by the phase-separation process. However, this method has reached its technological limit, and there have been no significant breakthrough over the last decade. Here we show, using polyvinylidene fluoride as a sample polymer, a new concept of membrane manufacturing by combining oriented green solvent crystallization and polymer migration is able to obtain high performance membranes with pure water permeation flux substantially higher than those with similar pore size prepared by conventional phase-separation processes. The new manufacturing procedure is governed by fewer operating parameters and is, thus, easier to control with reproducible results. Apart from the high water permeation flux, the prepared membranes also show excellent stable flux after fouling and superior mechanical properties of high pressure load and better abrasion resistance. These findings demonstrate the promise of a new concept for green manufacturing nanostructured polymeric membranes with high performances.

Design Principles in Polymer-Fullerene BHJ Solar Cells: PBDTTPD as a Case Study

KAUST Repository

Beaujuge, Pierre

2015-06-29

Among Organic Electronics, solution-processable π-conjugated polymers are proving particularly promising in bulk-heterojunction (BHJ) solar cells with fullerene acceptors such as PCBM.[1] In recent years, great headway has been made in the development of efficient polymer donors across the community, with published power conversion efficiencies (PCE) >8% in single cells and >10% in tandems. In most reports, these systems involve elaborate repeat unit and side chain patterns, and deviating from those patterns induces substantial drops in device PCE. While the range of polymer design parameters that impact BHJ solar cell performance remains a matter of some debate, our recent developments indicate that the combination of side-chain substituents appended to the main chain critically impacts polymer performance. For example, in poly(benzo[1,2-b:4,5-b’]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD), side-chain substituents of various size and branching impart distinct molecular packing distances (i.e., π–π stacking and lamellar spacing), varying degrees of nanostructural order in thin films, and preferential backbone orientation relative to the device substrate.[2-5] While these structural variations seem to correlate with BHJ solar cell performance, with power conversion efficiencies ranging from 4% to 8.5%,[2,3] we believe that other contributing parameters – such as the local conformations between the polymer and the fullerene, and the domain distribution/composition across the BHJ (i.e., pure/mixed phases) – should also be taken into account.[6,7] Other discrete modifications of PBDTTPD’s molecular structure affect polymer performance in BHJ solar cells with PCBM, and our recent developments emphasize how systematic structure-property relationship studies impact the design of efficient polymer donors for BHJ solar cell applications.[8-10] It is important to further our understanding of these effects as we look to continue improving BHJ solar

Structure and Dynamics of Polymer/Polymer grafted nanoparticle composite

Science.gov (United States)

Archer, Lynden

Addition of nanoparticles to polymers is a well-practiced methodology for augmenting various properties of the polymer host, including mechanical strength, thermal stability, barrier properties, dimensional stability and wear resistance. Many of these property changes are known to arise from nanoparticle-induced modification of polymer structure and chain dynamics, which are strong functions of the dispersion state of the nanoparticles' and on their relative size (D) to polymer chain dimensions (e.g. Random coil radius Rg or entanglement mesh size a) . This talk will discuss polymer nanocomposites (PNCs) comprised of Polyethylene Glycol (PEG) tethered silica nanoparticles (SiO2-PEG) dispersed in polymers as model systems for investigating phase stability and dynamics of PNCs. On the basis of small-angle X-ray Scattering, it will be shown that favorable enthalpic interactions between particle-tethered chains and a polymer host provides an important mechanism for creating PNCs in which particle aggregation is avoided. The talk will report on polymer and particle scale dynamics in these materials and will show that grafted nanoparticles well dispersed in a polymer host strongly influence the host polymer relaxation dynamics on all timescales and the polymers in turn produce dramatic changes in the nature (from diffusive to hyperdiffusive) and speed of nano particle decorrelation dynamics at the polymer entanglement threshold. A local viscosity model capable of explaining these observations is discussed and the results compared with scaling theories for NP motions in polymers This material is based on work supported by the National Science Foundation Award Nos. DMR-1609125 and CBET-1512297.

Experimental investigation of carbon monoxide poisoning effect on a PBI/H3PO4 high temperature polymer electrolyte membrane fuel cell

DEFF Research Database (Denmark)

Zhou, Fan; Andreasen, Søren Juhl; Kær, Søren Knudsen

2015-01-01

humidity level reduced the cell performance loss caused by CO poisoning. When the fuel cell was operated with pure H2, the cell performance was not significantly affect by the change in anode dew point temperature in the range of room temperature and 60 °C. CO2 in anode stream resulted in slight decrease...

Consequences of variation in stream-landscape connections for stream nitrate retention and export

Science.gov (United States)

Handler, A. M.; Helton, A. M.; Grimm, N. B.

2017-12-01

Hydrologic and material connections among streams, the surrounding terrestrial landscape, and groundwater systems fluctuate between extremes in dryland watersheds, yet the consequences of this variation for stream nutrient retention and export remain uncertain. We explored how seasonal variation in hydrologic connection among streams, landscapes, and groundwater affect nitrate and ammonium concentrations across a dryland stream network and how this variation mediates in-stream nitrate uptake and watershed export. We conducted spatial surveys of stream nitrate and ammonium concentration across the 1200 km2 Oak Creek watershed in central Arizona (USA). In addition, we conducted pulse releases of a solution containing biologically reactive sodium nitrate, with sodium chloride as a conservative hydrologic tracer, to estimate nitrate uptake rates in the mainstem (Q>1000 L/s) and two tributaries. Nitrate and ammonium concentrations generally increased from headwaters to mouth in the mainstem. Locally elevated concentrations occurred in spring-fed tributaries draining fish hatcheries and larger irrigation ditches, but did not have a substantial effect on the mainstem nitrogen load. Ambient nitrate concentration (as N) ranged from below the analytical detection limit of 0.005 mg/L to 0.43 mg/L across all uptake experiments. Uptake length—average stream distance traveled for a nutrient atom from the point of release to its uptake—at ambient concentration ranged from 250 to 704 m and increased significantly with higher discharge, both across streams and within the same stream on different experiment dates. Vertical uptake velocity and aerial uptake rate ranged from 6.6-10.6 mm min-1 and 0.03 to 1.4 mg N m-2 min-1, respectively. Preliminary analyses indicate potentially elevated nitrogen loading to the lower portion of the watershed during seasonal precipitation events, but overall, the capacity for nitrate uptake is high in the mainstem and tributaries. Ongoing work

Polymer dynamics from synthetic polymers to proteins

Indian Academy of Sciences (India)

Keywords. Polymer dynamics; reptation; domain dynamics biomolecules. Abstract. Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the ...

Influence of mineral fillers on the rheological response of polymer-modified bitumens and mastics

Directory of Open Access Journals (Sweden)

F. Cardone

2015-12-01

Full Text Available The rheological properties of the bituminous components (bitumen and bituminous mastic within asphalt mixtures contribute significantly to the major distresses of flexible pavements (i.e. rutting, fatigue and low temperature cracking. Asphalt mixtures are usually composed of mastic-coated aggregates rather than pure bitumen-coated aggregates. The purpose of this study is to investigate the effects of mineral fillers on the rheological behaviour of several polymer-modified bitumens (PMBs through laboratory mixing. A neat bitumen and two types of polymers (elastomeric and plastomeric were used to produce PMBs, and two fillers with different minerals (limestone and basalt were selected to obtain mastics. The dynamic shear rheometer (DSR and bending beam rheometer (BBR were used to characterize the rheological properties of PMBs and mastics. In particular, multiple stress creep recovery (MSCR tests were performed to evaluate the rutting potential at high temperatures, whereas BBR tests were carried out to investigate the low temperature behaviour of these materials. BBR results for unmodified mastics show that the increase of stiffness is similar regardless of the filler type, whereas results for polymer-modified mastics indicate that the degree of stiffening depends on the combination of filler/polymer types. MSCR results show that adding filler leads to a reduced susceptibility of permanent deformation and an enhanced elastic response, depending on the combination of filler/polymer types. Overall results suggest that a physical–chemical interaction between the filler and bitumen occurs, and that the interaction level is highly dependent on the type of polymer modification.

Incorporation of Znq2 complexes into mesoporous silica and their transparent polymer luminescent nanocomposites

International Nuclear Information System (INIS)

Du Yaying; Fu Yuqin; Shi Yongli; Lue Xiaodan; Lue Changli; Su Zhongmin

2009-01-01

Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent nanocomposites were prepared by in situ bulk polymerization. CMS nanoparticles or nanorods with hydroxyl-, mercapto- and sulfonic-functionalized interiors were obtained by different synthetic routes in the nanosize dimensions between 50 and 500 nm. The luminescent Znq 2 complex was successfully introduced in the pores of different mesoporous silicas by chemical adsorption as the driving force. The different internal circumstances of mesoporous silicas had an obvious effect on the luminescence and lifetime of Znq 2 complex. The transparent fluorescent nanocomposites were fabricated from different Znq 2 -CMS and suitable monomers. The Znq 2 -CMS were uniformly dispersed in the polymer matrix without evident aggregation. The photoluminescence properties of Znq 2 -CMS in the transparent matrix exhibited a dependence on the inner surrounding of CMS due to the interaction between Znq 2 -CMS and polymers. The maximum emission peak of the nanocomposites had a red-shift of 28 nm as compared to pure Znq 2 -CMS. - Graphical abstract: Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent fluorescent nanocomposites were prepared by in situ bulk polymerization. The figure shows the synthetic scheme for the Znq 2 -CMS and their transparent bulk nanocomposites.

Silk Fibroin/Polyvinyl Pyrrolidone Interpenetrating Polymer Network Hydrogels

Directory of Open Access Journals (Sweden)

Dajiang Kuang

2018-02-01

Full Text Available Silk fibroin hydrogel is an ideal model as biomaterial matrix due to its excellent biocompatibility and used in the field of medical polymer materials. Nevertheless, native fibroin hydrogels show poor transparency and resilience. To settle these drawbacks, an interpenetrating network (IPN of hydrogels are synthesized with changing ratios of silk fibroin/N-Vinyl-2-pyrrolidonemixtures that crosslink by H2O2 and horseradish peroxidase. Interpenetrating polymer network structure can shorten the gel time and the pure fibroin solution gel time for more than a week. This is mainly due to conformation from the random coil to the β-sheet structure changes of fibroin. Moreover, the light transmittance of IPN hydrogel can be as high as more than 97% and maintain a level of 90% within a week. The hydrogel, which mainly consists of random coil, the apertures inside can be up to 200 μm. Elastic modulus increases during the process of gelation. The gel has nearly 95% resilience under the compression of 70% eventually, which is much higher than native fibroin gel. The results suggest that the present IPN hydrogels have excellent mechanical properties and excellent transparency.

Streaming tearing mode

Science.gov (United States)

Shigeta, M.; Sato, T.; Dasgupta, B.

1985-01-01

The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

Estimating energy fluxes within the stream-aquifer interface of the Avenelles basin

Science.gov (United States)

Berrhouma, Asma; Rivière, Agnès; Goblet, Patrick; Cucchi, Karina; Rubin, Yoram; Baudin, Aurélien; Ansart, Patrick; Flipo, Nicolas

2017-04-01

The understanding of water temperature evolution and its associated energy fluxes is important to follow the aquatic habitats evolution and to predict future modifications induced by climate change. The spatio-temporal energy balance dynamics within the stream-aquifer interface is complex because of the multitude of physical, morphological and meteorological parameters on which it depends. This critical interface is involving numerous physical and bio-geochemical processes which are taking place at different time and spatial scales. The energy balance estimation at this interface depends mainly on the direction, magnitude and variability of water exchanges and the temporal variation of river and aquifer temperatures as well as the thermal porous media properties. In this work, a combined numerical and experimental approach is used to study the temporal and spatial evolution of the energy budget along 6 km of the stream network of the Avenelles watershed. With an area of 46 km2, the Avenelles watershed is located 70 km east from Paris. The Avenelles river presents different types of connectivity with the underlying aquifers. Five Local Monitoring Stations (LOMOS) have been deployed along the hydraulic corridor to monitor the water and thermal exchanges between the stream and aquifer over years, based on continuous pressure and temperature measurements in the river, the hyporheic zone (HZ) and the underlying aquifer. A 2D finite element thermo-hydrogeological model (METIS) coupled with a parameters screening script is used to determine the hydrogeological and thermal properties of the HZ and of the underlying aquifers by inversion at five LOMOS. Once the local models are calibrated, water and heat fluxes through the stream - aquifer interface are assessed over years (2012-2015) along the stream network. This work offers a new understanding of the stream-aquifer interface functioning, shifting from a pure hydrological characterizing toward a more subtle view that

The distribution of copper in stream sediments in an anomalous stream near Steinkopf, Namaqualand

International Nuclear Information System (INIS)

De Bruin, D.

1987-01-01

Anomalous copper concentrations detected by the regional stream-sediment programme of the Geological Survey was investigated in a stream near Steinkopf, Namaqualand. A follow-up disclosed the presence of malachite mineralization. However, additional stream-sediment samples collected from the 'anomalous' stream revealed an erratic distribution of copper and also that the malachite mineralization had no direct effect on the copper distribution in the stream sediments. Low partial-extraction yields, together with X-ray diffraction analyses, indicated that dispersion is mainly mechanical and that the copper occurs as cations in the lattice of the biotite fraction of the stream sediments. (author). 8 refs., 5 figs., 1 tab

The distribution of copper in stream sediments in an anomalous stream near Steinkopf, Namaqualand

Energy Technology Data Exchange (ETDEWEB)

De Bruin, D

1987-01-01

Anomalous copper concentrations detected by the regional stream-sediment programme of the Geological Survey was investigated in a stream near Steinkopf, Namaqualand. A follow-up disclosed the presence of malachite mineralization. However, additional stream-sediment samples collected from the 'anomalous' stream revealed an erratic distribution of copper and also that the malachite mineralization had no direct effect on the copper distribution in the stream sediments. Low partial-extraction yields, together with X-ray diffraction analyses, indicated that dispersion is mainly mechanical and that the copper occurs as cations in the lattice of the biotite fraction of the stream sediments. (author). 8 refs., 5 figs., 1 tab.

A morphological comparison of narrow, low-gradient streams traversing wetland environments to alluvial streams.

Science.gov (United States)

Jurmu, Michael C

2002-12-01

Twelve morphological features from research on alluvial streams are compared in four narrow, low-gradient wetland streams located in different geographic regions (Connecticut, Indiana, and Wisconsin, USA). All four reaches differed in morphological characteristics in five of the features compared (consistent bend width, bend cross-sectional shape, riffle width compared to pool width, greatest width directly downstream of riffles, and thalweg location), while three reaches differed in two comparisons (mean radius of curvature to width ratio and axial wavelength to width ratio). The remaining five features compared had at least one reach where different characteristics existed. This indicates the possibility of varying morphology for streams traversing wetland areas further supporting the concept that the unique qualities of wetland environments might also influence the controls on fluvial dynamics and the development of streams. If certain morphological features found in streams traversing wetland areas differ from current fluvial principles, then these varying features should be incorporated into future wetland stream design and creation projects. The results warrant further research on other streams traversing wetlands to determine if streams in these environments contain unique morphology and further investigation of the impact of low-energy fluvial processes on morphological development. Possible explanations for the morphology deviations in the study streams and some suggestions for stream design in wetland areas based upon the results and field observations are also presented.

InSTREAM: the individual-based stream trout research and environmental assessment model

Science.gov (United States)

Steven F. Railsback; Bret C. Harvey; Stephen K. Jackson; Roland H. Lamberson

2009-01-01

This report documents Version 4.2 of InSTREAM, including its formulation, software, and application to research and management problems. InSTREAM is a simulation model designed to understand how stream and river salmonid populations respond to habitat alteration, including altered flow, temperature, and turbidity regimes and changes in channel morphology. The model...

Re-Meandering of Lowland Streams

DEFF Research Database (Denmark)

Pedersen, Morten Lauge; Kristensen, Klaus Kevin; Friberg, Nikolai

2014-01-01

We evaluated the restoration of physical habitats and its influence on macroinvertebrate community structure in 18 Danish lowland streams comprising six restored streams, six streams with little physical alteration and six channelized streams. We hypothesized that physical habitats and macroinver...

Polymer compound

NARCIS (Netherlands)

1995-01-01

A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

Star Polymers.

Science.gov (United States)

Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

2016-06-22

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Synthesis of Pure Hydroxyapatite (Ca10 (PO46 (OH2 by the Sol –Gel Method and the Doxycycline Loaded in Presence of Gelatin for the Application of Drug Delivery DOI 10.2412/mmse.89.93.112

Directory of Open Access Journals (Sweden)

B. Shalini

2017-06-01

Full Text Available Hydroxyapatite (HAp is the most widely accepted biomaterial for the repair and reconstruction of bone tissue defects. The current study is based on HAp was synthesized using sol – gel method. The drug was loaded in presence of gelatin with pure HAp. Precursors like calcium nitrate tetrahydrate and diammonium hydrogen orthophosphate were used and ammonia solution was added to maintain the pH value at 10.5 throughout the reaction. The synthesized HAp and drug loaded HAp with gelatin were characterized using PXRD, FTIR, SEM, Drug loading, drug release studies. Results show that the average crystallite size for prepared HAp and drug loaded HAp with polymer are ~ 30 to 300 nm respectively was calculated using PXRD and morphology of pure HAp and drug loaded HAp with polymer was found using SEM. Drug loading and release percentage was calculated. Keeping the above points in the present study was aimed to produce the biocompatibility and bioactivity of HAp.

Experimental investigation of acoustic streaming in a cylindrical wave guide up to high streaming Reynolds numbers.

Science.gov (United States)

Reyt, Ida; Bailliet, Hélène; Valière, Jean-Christophe

2014-01-01

Measurements of streaming velocity are performed by means of Laser Doppler Velocimetry and Particle Image Velociimetry in an experimental apparatus consisting of a cylindrical waveguide having one loudspeaker at each end for high intensity sound levels. The case of high nonlinear Reynolds number ReNL is particularly investigated. The variation of axial streaming velocity with respect to the axial and to the transverse coordinates are compared to available Rayleigh streaming theory. As expected, the measured streaming velocity agrees well with the Rayleigh streaming theory for small ReNL but deviates significantly from such predictions for high ReNL. When the nonlinear Reynolds number is increased, the outer centerline axial streaming velocity gets distorted towards the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes. This kind of behavior is followed by outer streaming cells only and measurements in the near wall region show that inner streaming vortices are less affected by this substantial evolution of fast streaming pattern. Measurements of the transient evolution of streaming velocity provide an additional insight into the evolution of fast streaming.

Pure robotic retrocaval ureter repair

Directory of Open Access Journals (Sweden)

Ashok k. Hemal

2008-12-01

Full Text Available PURPOSE: To demonstrate the feasibility of pure robotic retrocaval ureter repair. MATERIALS AND METHODS: A 33 year old female presented with right loin pain and obstruction on intravenous urography with the classical "fish-hook" appearance. She was counseled on the various methods of repair and elected to have a robot assisted repair. The following steps are performed during a pure robotic retrocaval ureter repair. The patient is placed in a modified flank position, pneumoperitoneum created and ports inserted. The colon is mobilized to expose the retroperitoneal structures: inferior vena cava, right gonadal vein, right ureter, and duodenum. The renal pelvis and ureter are mobilized and the renal pelvis transected. The ureter is transposed anterior to the inferior vena cava and a pyelopyelostomy is performed over a JJ stent. RESULTS: This patient was discharged on postoperative day 3. The catheter and drain tube were removed on day 1. Her JJ stent was removed at 6 weeks postoperatively. The postoperative intravenous urography at 3 months confirmed normal drainage of contrast medium. CONCLUSION: Pure robotic retrocaval ureter is a feasible procedure; however, there does not appear to be any great advantage over pure laparoscopy, apart from the ergonomic ease for the surgeon as well the simpler intracorporeal suturing.

A Statistical Method to Predict Flow Permanence in Dryland Streams from Time Series of Stream Temperature

Directory of Open Access Journals (Sweden)

Ivan Arismendi

2017-12-01

Full Text Available Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs, to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels between April and August (2015–2016. We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%, but a portion of them showed one or more shifts among states (17%. We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature.

A statistical method to predict flow permanence in dryland streams from time series of stream temperature

Science.gov (United States)

Arismendi, Ivan; Dunham, Jason B.; Heck, Michael; Schultz, Luke; Hockman-Wert, David

2017-01-01

Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs), to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD) of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels) between April and August (2015–2016). We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%), but a portion of them showed one or more shifts among states (17%). We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature.

Characterizing commercial pureed foods: sensory, nutritional, and textural analysis.

Science.gov (United States)

Ettinger, Laurel; Keller, Heather H; Duizer, Lisa M

2014-01-01

Dysphagia (swallowing impairment) is a common consequence of stroke and degenerative diseases such as Parkinson's and Alzheimer's. Limited research is available on pureed foods, specifically the qualities of commercial products. Because research has linked pureed foods, specifically in-house pureed products, to malnutrition due to inferior sensory and nutritional qualities, commercial purees also need to be investigated. Proprietary research on sensory attributes of commercial foods is available; however direct comparisons of commercial pureed foods have never been reported. Descriptive sensory analysis as well as nutritional and texture analysis of commercially pureed prepared products was performed using a trained descriptive analysis panel. The pureed foods tested included four brands of carrots, of turkey, and two of bread. Each commercial puree was analyzed for fat (Soxhlet), protein (Dumas), carbohydrate (proximate analysis), fiber (total fiber), and sodium content (Quantab titrator strips). The purees were also texturally compared with a line spread test and a back extrusion test. Differences were found in the purees for sensory attributes as well as nutritional and textural properties. Findings suggest that implementation of standards is required to reduce variability between products, specifically regarding the textural components of the products. This would ensure all commercial products available in Canada meet standards established as being considered safe for swallowing.

Vacuum evaporation of pure metals

OpenAIRE

Safarian, Jafar; Engh, Thorvald Abel

2013-01-01

Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision...

Quantum mechanical simulations of polymers for molecular electronics and photonics

International Nuclear Information System (INIS)

Dupuis, M.; Villar, H.O.; Clementi, E.

1987-01-01

Ab initio quantum mechanical studies can play an important role in obtaining a detailed understanding of the electronic structure of existing materials, and in predicting the properties of new ones. In this article the authors give a general outline of their research activity in two areas dealing with new materials, specifically, conducting polymers and polymers with non-linear optical properties. The authors present the strategy followed for the study of these molecular systems, and an overview of their findings concerning the structure of the prototypical conducting polymer, i.e. pure and doped polyacetylene (PA). They focused attention on vibrational spectra and infrared and Raman intensities. The results of self-consistent-field (SCF) calculations on charged soliton-like molecules are consistent with experimental observation. In particular, they show that the theoretically established accidental mutual exclusion of infrared and Raman bands invalidates the requirement formulated on the basis of the interpretation of experimental data, that defects in PA must have local C/sub 2h/ symmetry. These conclusions are derived from extensive calculations for which supercomputer performance was imperative and carried out on the parallel supercomputer assembled at IBM-Kingston as a loosely coupled array of processors (LCAP). The authors briefly describe this computer system which has proven to be ideally suited to the methods of ab initio quantum chemistry

StreamQRE: Modular Specification and Efficient Evaluation of Quantitative Queries over Streaming Data.

Science.gov (United States)

Mamouras, Konstantinos; Raghothaman, Mukund; Alur, Rajeev; Ives, Zachary G; Khanna, Sanjeev

2017-06-01

Real-time decision making in emerging IoT applications typically relies on computing quantitative summaries of large data streams in an efficient and incremental manner. To simplify the task of programming the desired logic, we propose StreamQRE, which provides natural and high-level constructs for processing streaming data. Our language has a novel integration of linguistic constructs from two distinct programming paradigms: streaming extensions of relational query languages and quantitative extensions of regular expressions. The former allows the programmer to employ relational constructs to partition the input data by keys and to integrate data streams from different sources, while the latter can be used to exploit the logical hierarchy in the input stream for modular specifications. We first present the core language with a small set of combinators, formal semantics, and a decidable type system. We then show how to express a number of common patterns with illustrative examples. Our compilation algorithm translates the high-level query into a streaming algorithm with precise complexity bounds on per-item processing time and total memory footprint. We also show how to integrate approximation algorithms into our framework. We report on an implementation in Java, and evaluate it with respect to existing high-performance engines for processing streaming data. Our experimental evaluation shows that (1) StreamQRE allows more natural and succinct specification of queries compared to existing frameworks, (2) the throughput of our implementation is higher than comparable systems (for example, two-to-four times greater than RxJava), and (3) the approximation algorithms supported by our implementation can lead to substantial memory savings.

Study of SiO2/PMMA/CE tri-component interpenetrating polymer network composites

International Nuclear Information System (INIS)

Wang Junlong; Wang Chuang; Jiao Gengsheng; Wang Qiuya

2010-01-01

A technology of conjugated tri-component interpenetrating polymer networks was applied to synthesize a nano-SiO 2 /polymethylmethacrylate (PMMA)/cyanate (CE) composite through an asynchronous synthesis way. The microstructure of the composite was characterized using infrared spectroscopy (IR) and transmission electron microscopy (TEM). The mechanical properties were measured in German-made DL-1000B and XCL-40 universal material test machines, respectively. Results showed that both the impact strength and the flexural strength were in the optimum status when 3% SiO 2 /PMMA/CE was chosen as a sample with the PMMA/CE ratio of 20/80. Compared with the strengths of pure cyanate, those of the composite were raised by 137.28% and 31.29%, respectively. When 3% nano-SiO 2 was added, the impact strength was increased by 29.96% and the flexural strength by 20.05%, compared with the strengths of polymers without SiO 2 . Analysis and measurements by IR and TEM indicated that no chemical reactions took place among components in the composite. The interpenetration of the conjugated tri-component improved the loading capacity of the polymer, hence the toughness enhancement of cyanate.

Design Principles in Polymer-Fullerene BHJ Solar Cells: PBDTTPD as a Case Study

KAUST Repository

Beaujuge, Pierre

2015-01-01

For example, in poly(benzo[1,2-b:4,5-b’]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD), side-chain substituents of various size and branching impart distinct molecular packing distances (i.e., π–π stacking and lamellar spacing), varying degrees of nanostructural order in thin films, and preferential backbone orientation relative to the device substrate.[2-5] While these structural variations seem to correlate with BHJ solar cell performance, with power conversion efficiencies ranging from 4% to 8.5%,[2,3] we believe that other contributing parameters – such as the local conformations between the polymer and the fullerene, and the domain distribution/composition across the BHJ (i.e., pure/mixed phases) – should also be taken into account.[6,7] Other discrete modifications of PBDTTPD’s molecular structure affect polymer performance in BHJ solar cells with PCBM, and our recent developments emphasize how systematic structure-property relationship studies impact the design of efficient polymer donors for BHJ solar cell applications.[8-10] It is important to further our understanding of these effects as we look to continue improving BHJ solar cell efficiencies.

Facile synthesis of antimony-doped tin oxide nanoparticles by a polymer-pyrolysis method

International Nuclear Information System (INIS)

Li, Yuan-Qing; Wang, Jian-Lei; Fu, Shao-Yun; Mei, Shi-Gang; Zhang, Jian-Min; Yong, Kang

2010-01-01

In this article, antimony-doped tin oxide (ATO) nanoparticles was synthesized by a facile polymer-pyrolysis method. The pyrolysis behaviors of the polymer precursors prepared via in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry (TG-DSC). The structural and morphological characteristics of the products were studied by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). The results reveal that the ATO nanoparticles calcined at 600 o C show good crystallinity with the cassiterite structure and cubic-spherical like morphology. The average particle size of ATO decreases from 200 to 15 nm as the Sb doping content increases from 5 mol% to 15 mol%. Electrical resistivity measurement shows that the resistivity for the 10-13 mol% Sb-doped SnO 2 nanoparticles is reduced by more than three orders compared with the pure SnO 2 nanoparticles. In addition, due to its versatility this polymer-pyrolysis method can be extended to facile synthesis of other doped n-type semiconductor, such as In, Ga, Al doped ZnO, Sn doped In 2 O 3 .

Synthesis of organic liquids/geo-polymer composites for the immobilization of nuclear wastes

International Nuclear Information System (INIS)

Cantarel, Vincent

2016-01-01

This work is included in the management of radioactive organic liquids research field. The process is based on an emulsification of organic liquid in an alkali silicate solution allowing the synthesis of a geo-polymer matrix. The first part of this work consists in carrying out a screening on different organic liquids. A model system representative of the various oils and a geo-polymer reference formulation are then defined. The second part deals with the structuration of the organic liquid/geo-polymer structuration, from the mixture of the reactants to the final material. It aims at determining the phenomena allowing the synthesis of a homogeneous composite. The last two parts aim at characterizing the composite by studying its structure (chemical structure, porosity of the geo-polymer and dispersion of the oil) and its properties with respect to the application to the immobilization of radioactive waste. Unlike calcium silicate-based cementitious matrices, the structure of the geo-polymer is not affected by the chemical nature of the organic liquids. Only acid oils inhibit or slow down the geo-polymerization reaction. In order to obtain a homogeneous material, the presence of surfactant molecules is necessary. The emulsion stabilization mechanism at the base of the process is relying on a synergy between the surfactant molecules and the aluminosilicate particles present in the geo-polymer paste. The kinetics (chemical and mechanical) of the geo-polymerization are not impacted by the presence of oil or surfactants. Only an increase in the viscoelastic moduli and the elastic character of the pastes can be observed. This difference in rheological behavior is mainly due to the presence of surfactant. The structure of the matrix is identical to that of a pure geo-polymer of the same formulation. The organic liquid is dispersed in spherical inclusions whose radius is between 5 and 15 μm. These droplets are separated from each other, and from the environment by the

Pure natural inflation

Science.gov (United States)

Nomura, Yasunori; Watari, Taizan; Yamazaki, Masahito

2018-01-01

We point out that a simple inflationary model in which the axionic inflaton couples to a pure Yang-Mills theory may give the scalar spectral index (ns) and tensor-to-scalar ratio (r) in complete agreement with the current observational data.

Productivity of Stream Definitions

NARCIS (Netherlands)

Endrullis, Jörg; Grabmayer, Clemens; Hendriks, Dimitri; Isihara, Ariya; Klop, Jan

2007-01-01

We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continuously in such a way that a uniquely determined stream is obtained as the limit. Whereas productivity is undecidable

Productivity of stream definitions

NARCIS (Netherlands)

Endrullis, J.; Grabmayer, C.A.; Hendriks, D.; Isihara, A.; Klop, J.W.

2008-01-01

We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continually in such a way that a uniquely determined stream in constructor normal form is obtained as the limit. Whereas

Shape memory polymers

Energy Technology Data Exchange (ETDEWEB)

Wilson, Thomas S.; Bearinger, Jane P.

2017-08-29

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Shape memory polymers

Science.gov (United States)

Wilson, Thomas S.; Bearinger, Jane P.

2015-06-09

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Pure- and mixed-gas propylene/propane permeation properties of spiro- and triptycene-based microporous polyimides

KAUST Repository

Swaidan, Ramy J.; Ghanem, Bader; Swaidan, Raja; Litwiller, Eric; Pinnau, Ingo

2015-01-01

Solution-processable polyimides of intrinsic microporosity (PIM-PIs) comprising relatively inflexible and contorted backbones have demonstrated outstanding molecular-sieving behavior in membrane-based separation of gas/gas pairs. In this work, the effects of systematically increasing intra-chain rigidity on the propylene/propane separation properties were compared for PIM-PIs made from 2,3,5,6-tetramethyl-1,4-phenylene diamine (TMPD) and (i) spiro-centered dianhyride (SPDA-TMPD or PIM-PI-1) and (ii) 9,10-diisopropyltriptycene-based dianhydride (TPDA-TMPD or KAUST PI-1). Pure-gas experiments at 2 bar and 35 oC showed significant increases in C3H6 permeability and C3H6/C3H8 selectivity by transitioning from PIM-PI-1 (P(C3H6)=393 Barrer, α(C3H6/C3H8)=6) to KAUST-PI-1 (P(C3H6)=817 Barrer, α(C3H6/C3H8)=16), positioning KAUST-PI-1 considerably above the experimentally observed pure-gas C3H6/C3H8 polymer upper bound. However, 50:50 C3H6/C3H8 mixed-gas feeds induced significant losses in C3H6 permeability and C3H6/C3H8 selectivity relative to the 2 bar pure-gas data for PIM-PI-1 and KAUST-PI-1 as the C3H6/C3H8 selectivity dropped from 6 to 3 and 16 to 5, respectively, at 2 bar C3H6 partial pressure due to plasticization and competitive sorption.

Pure- and mixed-gas propylene/propane permeation properties of spiro- and triptycene-based microporous polyimides

KAUST Repository

Swaidan, Ramy Jawdat

2015-06-03

Solution-processable polyimides of intrinsic microporosity (PIM-PIs) comprising relatively inflexible and contorted backbones have demonstrated outstanding molecular-sieving behavior in membrane-based separation of gas/gas pairs. In this work, the effects of systematically increasing intra-chain rigidity on the propylene/propane separation properties were compared for PIM-PIs made from 2,3,5,6-tetramethyl-1,4-phenylene diamine (TMPD) and (i) spiro-centered dianhyride (SPDA-TMPD or PIM-PI-1) and (ii) 9,10-diisopropyltriptycene-based dianhydride (TPDA-TMPD or KAUST PI-1). Pure-gas experiments at 2 bar and 35 oC showed significant increases in C3H6 permeability and C3H6/C3H8 selectivity by transitioning from PIM-PI-1 (P(C3H6)=393 Barrer, α(C3H6/C3H8)=6) to KAUST-PI-1 (P(C3H6)=817 Barrer, α(C3H6/C3H8)=16), positioning KAUST-PI-1 considerably above the experimentally observed pure-gas C3H6/C3H8 polymer upper bound. However, 50:50 C3H6/C3H8 mixed-gas feeds induced significant losses in C3H6 permeability and C3H6/C3H8 selectivity relative to the 2 bar pure-gas data for PIM-PI-1 and KAUST-PI-1 as the C3H6/C3H8 selectivity dropped from 6 to 3 and 16 to 5, respectively, at 2 bar C3H6 partial pressure due to plasticization and competitive sorption.

Low-temperature plasma-catalytic oxidation of formaldehyde in atmospheric pressure gas streams

International Nuclear Information System (INIS)

Ding Huixian; Zhu Aimin; Lu Fugong; Xu Yong; Zhang Jing; Yang Xuefeng

2006-01-01

Formaldehyde (HCHO) is a typical air pollutant capable of causing serious health disorders in human beings. This work reports plasma-catalytic oxidation of formaldehyde in gas streams via dielectric barrier discharges over Ag/CeO 2 pellets at atmospheric pressure and 70 0 C. With a feed gas mixture of 276 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼99% of formaldehyde can be effectively destructed with an 86% oxidative conversion into CO 2 at GHSV of 16500 h -1 and input discharge energy density of 108 J l -1 . At the same experimental conditions, the conversion percentages of HCHO to CO 2 from pure plasma-induced oxidation (discharges over fused silica pellets) and from pure catalytic oxidation over Ag/CeO 2 (without discharges) are 6% and 33% only. The above results and the CO plasma-catalytic oxidation experiments imply that the plasma-generated short-lived gas phase radicals, such as O and HO 2 , play important roles in the catalytic redox circles of Ag/CeO 2 to oxidize HCHO and CO to CO 2

Nanoindentation of Functionally Graded Polymer Nanocomposites: Assessment of the Strengthening Parameters through Experiments and Modeling

Directory of Open Access Journals (Sweden)

Tommaso eNardi

2015-08-01

Full Text Available NNanoindentation tests were carried out on the surface of polymer nanocomposites exhibiting either graded or homogeneous distributions of Fe3O4@silica core-shell nanoparticles in a photocurable polymeric matrix. The results reveal a complex interplay between graded morphology, indentation depth and calculated modulus and hardness values, which was elucidated through numerical simulations. First, it was experimentally shown how for small (1 µm indentations, large increases in modulus (up to +40% and hardness (up to +93% were obtained for graded composites with respect to their homogeneous counterparts, whereas at a larger indentation depth (20 µm the modulus and hardness of the graded and homogeneous composites did not substantially differ from each other and from those of the pure polymer. Then, through a Material Point Method approach, experimental nanoindentation tests were successfully simulated, confirming the importance of the indentation depth and of the associated plastic zone as key factors for a more accurate design of graded polymer nanocomposites whose mechanical properties are able to fulfill the requirements encountered during operational life.

Polymers – A New Open Access Scientific Journal on Polymer Science

Directory of Open Access Journals (Sweden)

Shu-Kun Lin

2009-12-01

Full Text Available Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI. This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, if accepted, within 6 to 8 weeks after submission. [...

Development of Innovating Materials for Distributing Mixtures of Hydrogen and Natural Gas. Study of the Barrier Properties and Durability of Polymer Pipes

Directory of Open Access Journals (Sweden)

Klopffer Marie-Hélène

2015-02-01

Full Text Available With the growing place taken by hydrogen, a question still remains about its delivery and transport from the production site to the end user by employing the existing extensive natural gas pipelines. Indeed, the key challenge is the significant H2 permeation through polymer infrastructures (PolyEthylene (PE pipes, components such as connecting parts. This high flow rate of H2 through PE has to be taken into account for safety and economic requirements. A 3-year project was launched, the aim of which was to develop and assess material solutions to cope with present problems for hydrogen gas distribution and to sustain higher pressure compared to classical high density polyethylene pipe. This project investigated pure hydrogen gas and mixtures with natural gas (20% of CH4 and 80% of H2 in pipelines with the aim to select engineering polymers which are more innovative than polyethylene and show outstanding properties, in terms of permeation, basic mechanical tests but also more specific characterizations such as long term ageing and behaviour. The adequate benches, equipments and scientific approach for materials testing had been developed and validated. In this context, the paper will focus on the evaluation of the barrier properties of 3 polymers (PE, PA11 and PAHM. Experiments were performed for pure H2 and CH4 and also in the presence of mixtures of hydrogen and natural gas in order to study the possible mixing effects of gases. It will report some round-robin tests that have been carried out. Secondly, by comparing data obtained on film, polymer membrane and on pipe section, the influence of the polymer processing will be studied. Innovative multilayers systems will be proposed and compared on the basis of the results obtained on monolayer systems. Finally, the evolution of the transport properties of the studied polymers with an ageing under representative service conditions will be discussed.

Conformal pure radiation with parallel rays

International Nuclear Information System (INIS)

Leistner, Thomas; Paweł Nurowski

2012-01-01

We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then, we derive conditions in terms of the tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give analogous results for n-dimensional pseudo-Riemannian pp-waves. (paper)

Streams and their future inhabitants

DEFF Research Database (Denmark)

Sand-Jensen, K.; Friberg, Nikolai

2006-01-01

In this fi nal chapter we look ahead and address four questions: How do we improve stream management? What are the likely developments in the biological quality of streams? In which areas is knowledge on stream ecology insuffi cient? What can streams offer children of today and adults of tomorrow?...

Salamander occupancy in headwater stream networks

Science.gov (United States)

Grant, E.H.C.; Green, L.E.; Lowe, W.H.

2009-01-01

1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

Polymer chemistry (revised edition)

International Nuclear Information System (INIS)

Kim, Jae Mum

1987-02-01

This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

Enhanced quantum efficiency in blue-emitting polymer/dielectric nanolayer nanocomposite light-emitting devices

International Nuclear Information System (INIS)

Park, Jong Hyeok; Lim, Yong Taik; Park, O Ok; Yu, Jae-Woong; Kim, Jai Kyeong; Kim, Young Chul

2004-01-01

Light-emitting devices based on environmentally stable, blue-emitting polymer/dielectric nanolayer nanocomposites were fabricated by blending poly(di-octylfluorene) (PDOF) with organo-clay. By reducing the excimer formation that leads to long wavelength tails, the photoluminescence (PL) and electroluminescence (EL) color purity of the device was enhanced. When a conjugated polymer/dielectric nanolayer nanocomposite is applied to an EL device, we expect an electronic structure similar to the well-known quantum well in small nanodomains. The ratio of PDOF/organo-clay was regulated from 2:1 to 0.5:1 (w/w). The light-emitting device of 0.5:1 (w/w) blend demonstrated the highest quantum efficiency (QE), 0.72% (ph/el), which is ∼500 times higher value compared with that of the pure PDOF layer device. However, the driving voltage of the nanocomposite devices tended to increase with increasing organo-clay content

Integration of conducting polymer network in non-conductive polymer substrates

DEFF Research Database (Denmark)

Hansen, Thomas Steen; West, Keld; Hassager, Ole

2006-01-01

Anew method for integration ofconjugated, inherently conducting polymers into non-conductive polymer substrates has been developed. Alayer of the conducting polymer is polymerised by chemical oxidation, e.g. using Fe(ID) p-toluene sulfonate (ferri tosylate) followed by washing with a solvent which...... simultaneously removes residual and spent oxidant and at the same time dissolves the top layer of the polymer substrate. This results in an integration of the conducting polymer into the surface layers of the polymer substrate. Several combinations of conducting polymers and substrates have been tested...... absorption during sequential reactive ion etching has allowed for analysis of the PEDOT distribution within the surface layer of thePMMA substrate. The surface resistance ofthe conducting polymer layer remains low while the surface layer at the same time adapts some of the mechanical properties...

Pure spinor partition function and the massive superstring spectrum

International Nuclear Information System (INIS)

Aisaka, Yuri; Arroyo, E. Aldo; Berkovits, Nathan; Nekrasov, Nikita

2008-01-01

We explicitly compute up to the fifth mass-level the partition function of ten-dimensional pure spinor worldsheet variables including the spin dependence. After adding the contribution from the (x μ , θ α , p α ) matter variables, we reproduce the massive superstring spectrum. Even though pure spinor variables are bosonic, the pure spinor partition function contains fermionic states which first appear at the second mass-level. These fermionic states come from functions which are not globally defined in pure spinor space, and are related to the b ghost in the pure spinor formalism. This result clarifies the proper definition of the Hilbert space for pure spinor variables.

Dynamics of polymers in a good solvent - a molecular dynamics study using the Connection Machine

International Nuclear Information System (INIS)

Shannon, S.R.; Choy, T.C.

1996-01-01

In recent times the use of molecular dynamics simulations has become an important tool in modelling and understanding the dynamics of interacting many-body systems. With recent advances in computing power it is now feasible to perform modelling of systems which contain a large number of interacting particles, and thus to simulate the behaviour of real systems reasonably. Our earlier discoveries of anomalous corrections to scaling behaviour of the Edward's polymer were applied to study the dynamical behaviour of two dimensional polymer systems - either a single chain immersed in a fluid, a pure polymer melt, or with any concentration of polymers in the fluid. By choosing a suitable interaction potential between the fluid particles and the monomers, we are able to study the experimentally observable time dependent structure factor of polymers in a good solvent. Simulations were performed using the Connection Machine CM5 supercomputer at the Australian National University which due to its fast multi- processor nearest neighbour communications facility, enables us to easily model large systems of at least 3000 fluid plus monomer particles. Our study is based on a finite difference solution of Newton's equations of motion i.e. the Verlet algorithm, and the results are used to test current theories of polymer dynamics, which were based primarily on the earlier models proposed by Rouse (1953) and Zimm (1956). In particular dynamical scaling predictions is scrutinised to examine the effects due to the anomalous corrections-to-scaling behaviour found in an earlier work using finite-size scaling analysis of Monte-Carlo data and now understood via a new perturbation concept

Mechanical and thermal properties of promising polymer composites for food packaging applications

Science.gov (United States)

Abdellah Ali, S. F.

2016-07-01

Blending starches with biodegradable polycaprolactone (PCL) was used as a route to make processable thermoplastics. When developing biodegradable polymer composites it is important to use high concentrations of starch for legislative and cost reasons. The addition of starch has a significant effect on all physical properties including toughness, elongation at break and the rheological behaviour of the melt. To enhance the physical properties, we used cellulose acetate propionate (CAP) as a cellulose derivative with high amylase starch and PCL blends. It is suggested that the PCL/starch/CAP blends are partially miscible. It was found that the yield tensile strengths of most PCL/Starch/CAP blends were higher than that of pure PCL itself. There was a big difference between glass transition temperature values of PCL/Starch/CAP blends and the pure PCL glass transition temperature which indicates that no phase separation occurs. Addition of CAP to starch and PCL blends improved the mechanical and thermal properties even at high content of starch.

Component dynamics in polymer blends a combined QENS and dielectric spectroscopy investigation

CERN Document Server

Hofmann, S; Arbe, A; Colmenero, J; Faragó, B

2002-01-01

The individual dynamics of the two constituents of a binary polymer blend was studied by means of quasielastic neutron scattering and dielectric spectroscopy (DS). The combination of neutron spin-echo and backscattering techniques allowed us to cover the complete crossover from entropy-driven chain dynamics on mesoscopic scales to the alpha relaxation on local length scales. The observed blending effects on the respective relaxation times suggest a purely dynamic origin of the dynamic heterogeneity in polymer blends at temperatures well above the glass-transition temperature without the need to assume local phase separation. In contrast, the results from DS experiments towards much lower temperatures indicate systematic deviations of the segmental dynamics in the blend from its mean-field-like behavior at high temperatures. This additionally increases the dynamic heterogeneity in the segmental dynamics of the two components in the mixture. In the case of the chain dynamics, no similar effect could be observed...

Testing effects in mixed- versus pure-list designs.

Science.gov (United States)

Rowland, Christopher A; Littrell-Baez, Megan K; Sensenig, Amanda E; DeLosh, Edward L

2014-08-01

In the present study, we investigated the role of list composition in the testing effect. Across three experiments, participants learned items through study and initial testing or study and restudy. List composition was manipulated, such that tested and restudied items appeared either intermixed in the same lists (mixed lists) or in separate lists (pure lists). In Experiment 1, half of the participants received mixed lists and half received pure lists. In Experiment 2, all participants were given both mixed and pure lists. Experiment 3 followed Erlebacher's (Psychological Bulletin, 84, 212-219, 1977) method, such that mixed lists, pure tested lists, and pure restudied lists were given to independent groups. Across all three experiments, the final recall results revealed significant testing effects for both mixed and pure lists, with no reliable difference in the magnitude of the testing advantage across list designs. This finding suggests that the testing effect is not subject to a key boundary condition-list design-that impacts other memory phenomena, including the generation effect.

Nanoscale Mechanical Characterization of Graphene/Polymer Nanocomposites using Atomic Force Microscopy

Science.gov (United States)

Cai, Minzhen

Graphene materials, exhibiting outstanding mechanical properties, are excellent candidates as reinforcement in high-performance polymer nanocomposites. In this dissertation, advanced atomic force microscopy (AFM) techniques are applied to study the nanomechanics of graphene/polymer nanocomposites, specifically the graphene/polymer interfacial strength and the stress transfer at the interface. Two novel methods to directly characterize the interfacial strength between individual graphene sheets and polymers using AFM are presented and applied to a series of polymers and graphene sheets. The interfacial strength of graphene/polymer varies greatly for different combinations. The strongest interaction is found between graphene oxide (GO) and polyvinyl alcohol (PVA), a strongly polar, water-based polymer. On the other hand, polystyrene, a non polar polymer, has the weakest interaction with GO. The interfacial bond strength is attributed to hydrogen bonding and physical adsorption. Further, the stress transfer in GO/PVA nanocomposites is studied quantitatively by monitoring the strain in individual GO sheet inside the polymer via AFM and Raman spectroscopy. For the first time, the strains of individual GO sheets in nanocomposites are imaged and quantified as a function of the applied external strains. The matrix strain is directly transferred to GO sheets for strains up to 8%. At higher strain levels, the onset of the nanocomposite failure and a stick-slip behavior is observed. This study reveals that GO is superior to pure graphene as reinforcement in nanocomposites. These results also imply the potential to make a new generation of nanocomposites with exceptional high strength and toughness. In the second part of this dissertation, AFM is used to study the structure of silk proteins and the morphology of spider silks. For the first time, shear-induced self-assembly of native silk fibroin is observed. The morphology of the Brown Recluse spider silk is investigated and a

Impaired communication between the dorsal and ventral stream: indications from apraxia

Directory of Open Access Journals (Sweden)

Carys eEvans

2016-02-01

accurately, apraxic patients applied neither pure knowledge-based information (the memory-associated condition nor higher-level information given in the visual-spatial cue condition. Disruption to ventro-dorsal stream predicts that apraxic patients will have difficulty learning to manipulate new objects on the basis of information other than low-level visual cues such as shape and size.

Fluorination of polymers

International Nuclear Information System (INIS)

Du Toit, F.J.

1991-01-01

Polyethylene and polypropylene were reacted with elemental fluorine under carefully controlled conditions to produce fluorocarbon polymers. Fluorination of polymer films resulted in fluorination of only the outer surfaces of the films, while the reaction of elemental fluorine with powdered hydrocarbon polymers produced perfluorocarbon polymers. Existing and newly developed techniques were used to characterize the fluorinated polymers. It was shown that the degree of fluorination was influenced by the surface area of the hydrocarbon material, the concentration, of the fluorine gas, and the time and temperature of fluorination. A fluidized-bed reactor used for the fluorination of polymer powders effectively increased the reaction rate. The surface tension and the oxygen permeability of the fluorinated polymers were studied. The surface tension of hydrocarbon polymers was not influenced by different solvents, but the surface tension of fluorinated polymers was affected by the type of solvent that was used. There were indications that the surface tension was affected by oxygen introduced into the polymer surface during fluorination. Fluorination lowered the permeability of oxygen through hydrocarbon polymers. 55 refs., 51 figs., 26 tabs

Stream hydraulics and temperature determine the metabolism of geothermal Icelandic streams

Directory of Open Access Journals (Sweden)

Demars B. O.L.

2011-07-01

Full Text Available Stream ecosystem metabolism plays a critical role in planetary biogeochemical cycling. Stream benthic habitat complexity and the available surface area for microbes relative to the free-flowing water volume are thought to be important determinants of ecosystem metabolism. Unfortunately, the engineered deepening and straightening of streams for drainage purposes could compromise stream natural services. Stream channel complexity may be quantitatively expressed with hydraulic parameters such as water transient storage, storage residence time, and water spiralling length. The temperature dependence of whole stream ecosystem respiration (ER, gross primary productivity (GPP and net ecosystem production (NEP = GPP − ER has recently been evaluated with a “natural experiment” in Icelandic geothermal streams along a 5–25 °C temperature gradient. There remained, however, a substantial amount of unexplained variability in the statistical models, which may be explained by hydraulic parameters found to be unrelated to temperature. We also specifically tested the additional and predicted synergistic effects of water transient storage and temperature on ER, using novel, more accurate, methods. Both ER and GPP were highly related to water transient storage (or water spiralling length but not to the storage residence time. While there was an additional effect of water transient storage and temperature on ER (r2 = 0.57; P = 0.015, GPP was more related to water transient storage than temperature. The predicted synergistic effect could not be confirmed, most likely due to data limitation. Our interpretation, based on causal statistical modelling, is that the metabolic balance of streams (NEP was primarily determined by the temperature dependence of respiration. Further field and experimental work is required to test the predicted synergistic effect on ER. Meanwhile, since higher metabolic activities allow for higher pollutant degradation or uptake

Tractable Quantification of Entanglement for Multipartite Pure States

International Nuclear Information System (INIS)

Nian-Quan, Jiang; Yu-Jian, Wang; Yi-Zhuang, Zheng; Gen-Chang, Cai

2008-01-01

We present kth-order entanglement measure and global kth-order entanglement measure for multipartite pure states, and extend Bennett's measure of partial entropy for bipartite pure states to a multipartite case. These measures are computable and can effectively classify and quantify the entanglement of multipartite pure states. (general)

Gate-Driven Pure Spin Current in Graphene

Science.gov (United States)

Lin, Xiaoyang; Su, Li; Si, Zhizhong; Zhang, Youguang; Bournel, Arnaud; Zhang, Yue; Klein, Jacques-Olivier; Fert, Albert; Zhao, Weisheng

2017-09-01

The manipulation of spin current is a promising solution for low-power devices beyond CMOS. However, conventional methods, such as spin-transfer torque or spin-orbit torque for magnetic tunnel junctions, suffer from large power consumption due to frequent spin-charge conversions. An important challenge is, thus, to realize long-distance transport of pure spin current, together with efficient manipulation. Here, the mechanism of gate-driven pure spin current in graphene is presented. Such a mechanism relies on the electrical gating of carrier-density-dependent conductivity and spin-diffusion length in graphene. The gate-driven feature is adopted to realize the pure spin-current demultiplexing operation, which enables gate-controllable distribution of the pure spin current into graphene branches. Compared with the Elliott-Yafet spin-relaxation mechanism, the D'yakonov-Perel spin-relaxation mechanism results in more appreciable demultiplexing performance. The feature of the pure spin-current demultiplexing operation will allow a number of logic functions to be cascaded without spin-charge conversions and open a route for future ultra-low-power devices.

Electric field induced dewetting at polymer/polymer interfaces

NARCIS (Netherlands)

Lin, Z.Q.; Kerle, T.; Russell, T.P.; Schäffer, E.; Steiner, U

2002-01-01

External electric fields were used to amplify interfacial fluctuations in the air/polymer/polymer system where one polymer dewets the other. Two different hydrodynamic regimes were found as a function of electric field strength. If heterogeneous nucleation leads to the formation of holes before the

White polymer light-emitting diode based on polymer blending

International Nuclear Information System (INIS)

Lee, Yong Kyun; Kwon, Soon Kab; Kim, Jun Young; Park, Tae Jin; Song, Dae Ho; Kwon, Jang Hyuk; Choo, Dong Jun; Jang, Jin; Jin, Jae Kyu; You, Hong

2006-01-01

A series of white polymer light emitting devices have been fabricated by using a polymer blending system of polyfluorene-based blue and MEH-PPV red polymers. A device structure of ITO/PEDOT:PSS/polymer/LiF/Al was employed. The white polymer device exhibited a current efficiency of 4.33 cd/A (4,816 cd/m 2 , Q.E. = 1.9 %) and a maximum luminance of 21,430 cd/m 2 at 9.2 V. The CIE coordinates were (0.35, 0.37) at 5 V and (0.29, 0.30) at 9 V.

Pure natural inflation

Directory of Open Access Journals (Sweden)

Yasunori Nomura

2018-01-01

Full Text Available We point out that a simple inflationary model in which the axionic inflaton couples to a pure Yang–Mills theory may give the scalar spectral index (ns and tensor-to-scalar ratio (r in complete agreement with the current observational data.

Nitrogen saturation in stream ecosystems.

Science.gov (United States)

Earl, Stevan R; Valett, H Maurice; Webster, Jackson R

2006-12-01

The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer (15NO3-N) to measure uptake. Experiments were conducted in streams spanning a gradient of background N concentration. Uptake increased in four of six streams as NO3-N was incrementally elevated, indicating that these streams were not saturated. Uptake generally corresponded to Michaelis-Menten kinetics but deviated from the model in two streams where some other growth-critical factor may have been limiting. Proximity to saturation was correlated to background N concentration but was better predicted by the ratio of dissolved inorganic N (DIN) to soluble reactive phosphorus (SRP), suggesting phosphorus limitation in several high-N streams. Uptake velocity, a reflection of uptake efficiency, declined nonlinearly with increasing N amendment in all streams. At the same time, uptake velocity was highest in the low-N streams. Our conceptual model of N transport, uptake, and uptake efficiency suggests that, while streams may be active sites of N uptake on the landscape, N saturation contributes to nonlinear changes in stream N dynamics that correspond to decreased uptake efficiency.

Triacrylate of glycerin synthesis and use in network polymer

International Nuclear Information System (INIS)

Morita, Reinaldo Y.; Zawadzki, Sonia F.; Barbosa, Ronilson V.

2009-01-01

The goal of this work was the synthesis and characterization of a new cross linker: the glyceryl triacrylate. The synthesis was done by an esterification reaction between glycerin and acrylic acid and the product, called GA, was characterized by infrared and nuclear magnetic resonance (NMR- 1a) spectroscopy. The behavior was analysed after a copolymerization with methyl methacrylate monomer (MMA). It was also prepared the PMMA and GA homopolymers. The addition of glycerin triacrylate up to 2 % in the MMA monomer changed the solubility of the copolymer. This one became insoluble in organic solvents in which the pure linear poly(methyl methacrylate) was soluble. Thermal analysis showed that the addition of 2% GA didn't change the Tg value of the PMMA pure, but the GA homopolymer showed a Tg value equal to 180 C, lower than expected. It seems that GA product is working as cross linker, but some insaturation links did not react. They remain as pendent groups, causing the Tg lowering. The results suggest that the new product can be used as cross linker for the application in acrylic polymers. (author)

Pure chiral optical fibres.

Science.gov (United States)

Poladian, L; Straton, M; Docherty, A; Argyros, A

2011-01-17

We investigate the properties of optical fibres made from chiral materials, in which a contrast in optical activity forms the waveguide, rather than a contrast in the refractive index; we refer to such structures as pure chiral fibres. We present a mathematical formulation for solving the modes of circularly symmetric examples of such fibres and examine the guidance and polarisation properties of pure chiral step-index, Bragg and photonic crystal fibre designs. Their behaviour is shown to differ for left- and right-hand circular polarisation, allowing circular polarisations to be isolated and/or guided by different mechanisms, as well as differing from equivalent non-chiral fibres. The strength of optical activity required in each case is quantified.

Microscopic theory for dynamics in entangled polymer nanocomposites

Science.gov (United States)

Yamamoto, Umi

includes the sphere excluded volume effect. Coupled self-consistent equations for the generalized diffusion tensors are constructed, and the expressions for the transverse localization lengths and the long-time diffusion coefficients are derived. In the static sphere limit, we find the effective tube diameter is generally reduced as a function of a single confinement parameter that quantifies the number of particles penetrating into the pure-polymer tube. A preliminary extension to treat flexible chain melts has also been achieved, and shown to agree reasonably well with simulations. The anisotropic needle diffusion constants are rich functions of the length-scale ratios, needle concentration and particle volume fraction. We show that the steric blocking of the longitudinal motion causes a literal and simultaneous localization of the two diffusion channels, and entangled needles can diffuse via a modified reptation dynamics over a window of polymer concentration but the compression of the tube and the blocking of the reptation motion must be accounted for. Generalization to treat mobile spheres is also possible and fully formulated.

A noncovalent functionalization approach to improve the dispersibility and properties of polymer/MoS2 composites

International Nuclear Information System (INIS)

Zhou, Keqing; Liu, Jiajia; Wen, Panyue; Hu, Yuan; Gui, Zhou

2014-01-01

Highlights: • In this work, we have reported a convenient method to modify molybdenum disulfide (MoS 2 ) nanosheets. • The organic modified MoS 2 nanosheets dispersed well in organic solvents and aqueous solution simultaneously. • This well dispersion can be used to prepare polymer/MoS 2 nanocomposites with an exfoliation structure by a simple solvent mixing method. • The organic modified MoS 2 nanosheets show promising reinforcing efficiency in the thermal stability, fire resistance and thermomechanical properties of the polymer/MoS 2 nanocomposites. - Abstract: In the evolution of high performance layered inorganic compounds/polymer nanocomposites, homogeneous dispersion of inorganic nanoplatelets in the polymer matrix and exact interface control are difficult to achieve due to the potent interlayer cohesive energy and surface inactiveness of the nanocomposites. Pristine MoS 2 exhibits poor solubility in both water and organic solvents. Herein, it is necessary to modify the surface of molybdenum disulfide (MoS 2 ) nanosheets with functional groups, in order to enhance its dispersity and compatibility in various solvents and polymer matrices. In this paper, we have reported a convenient method to modify MoS 2 nanosheets with common cationic surfactant and polymer, these organic modified MoS 2 nanosheets dispersed well in organic solvents and aqueous solution simultaneously. This well dispersion can be used to prepare polymer/MoS 2 nanocomposites by a simple solvent mixing method which was found to display an exfoliation structure of MoS 2 nanosheets and improve the performances of the polymer nanocomposites. With the addition of 3 wt% CTAB-MoS 2 , T 10% and T 50% of the samples are increased by 60 °C, respectively. Moreover, the storage modulus of sample PS/3% CTAB-MoS 2 had 84% increment compared with that of pure PS at 30 °C

Regeneration strategies of polymers employed in ex-situ remediation of contaminated soil: Bioregeneration versus solvent extraction.

Science.gov (United States)

Mosca Angelucci, Domenica; Tomei, M Concetta

2015-08-15

In this study we evaluated the feasibility of two regeneration strategies of contaminated polymers employed for ex-situ soil remediation in a two-step process. Soil decontamination is achieved by sorption of the pollutants on the polymer beads, which are regenerated in a subsequent step. Tested soil was contaminated with a mixture of 4-chlorophenol and pentachlorophenol, and a commercial polymer, Hytrel, has been employed for extraction. Removal efficiencies of the polymer-soil extraction are in the range of 51-97% for a contact time ≤ 24 h. Two polymer regeneration strategies, solvent extraction and biological regeneration (realized in a two-phase partitioning bioreactor), were tested and compared. Performance was assessed in terms of removal rates and efficiencies and an economic analysis based on the operating costs has been performed. Results demonstrated the feasibility of both regeneration strategies, but the bioregeneration was advantageous in that provided the biodegradation of the contaminants desorbed from the polymer. Practically complete removal for 4-chlorophenol and up to 85% biodegradation efficiency for pentachlorophenol were achieved. Instead, in the solvent extraction, a relevant production (184-831 L kg(pol)(-1)) of a highly polluted stream to be treated or disposed of is observed. The cost analysis of the two strategies showed that the bioregeneration is much more convenient with operating costs of ∼12 €/kg(pol) i.e. more than one order of magnitude lower in comparison to ∼233 €/kg(pol) of the solvent extraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Percent Forest Adjacent to Streams

Data.gov (United States)

U.S. Environmental Protection Agency — The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept...

Percent Agriculture Adjacent to Streams

Data.gov (United States)

U.S. Environmental Protection Agency — The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept...

NOCHAR Polymers: An Aqueous and Organic Liquid Solidification Process for Cadarache LOR (Liquides Organiques Radioactifs) - 13195

International Nuclear Information System (INIS)

Vaudey, Claire-Emilie; Renou, Sebastien; Porco, Julien; Kelley, Dennis; Cochaud, Chantal; Serrano, Roger

2013-01-01

To handle the Very Low Level Waste (VLLW) and the Low Level Waste (LLW) in France, two options can be considered: the incineration at CENTRACO facility and the disposal facility on ANDRA sites. The waste acceptance in these radwaste routes is dependent upon the adequacy between the waste characteristics (physical chemistry and radiological) and the radwaste route specifications. If the waste characteristics are incompatible with the radwaste route specifications (presence of significant quantities of chlorine, fluorine, organic component etc or/and high activity limits), it is necessary to find an alternative solution that consists of a waste pre-treatment process. In the context of the problematic Cadarache LOR (Liquides Organiques Radioactifs) waste streams, two radioactive scintillation cocktails have to be treated. The first one is composed of organic liquids at 13.1 % (diphenyloxazol, mesitylene, TBP, xylene) and water at 86.9 %. The second one is composed of TBP at 8.6 % and water at 91.4 %. They contain chlorine, fluorine and sulphate and have got alpha/beta/gamma spectra with mass activities equal to some kBq.g -1 . Therefore, tritium is present and creates the second problematic waste stream. As a consequence, in order for disposal acceptance at the ANDRA site, it is necessary to pre-treat the waste. The NOCHAR polymers as an aqueous and organic liquid solidification process seem to be an adequate solution. Indeed, these polymers constitute an important variety of products applied to the treatment of radioactive aqueous and organic liquids (solvent, oil, solvent/oil mixing etc) and sludge through a mechanical and chemical solidification process. For Cadarache LOR, N910 and N960 respectively dedicated to the organic and aqueous liquids solidification are considered. With the N910, the organic waste solidification occurs in two steps. As the organic liquid travels moves through the polymer strands, the strands swell and immobilise the liquid. Then as the

Stream Level Stabilization by Algae of the Genus Cladophora

Directory of Open Access Journals (Sweden)

Zeman J.

2018-03-01

Full Text Available Investigations in the Pryský brook experimental catchment revealed that the vegetation of the stream channel stabilizes water level depth in the measured profile. The explored brook has been heavily overgrown by algae of the genus Cladophora due to a strong pollution by nitrates. It seems that if the algae average length exceeds the midsize of the stones paving the bed (ca. 30 ± 7 cm in diameter, escribed circle to pentagon or heptagon, the water level stagnates in the flowrate range of 60–180 l s−1. This totally blocks the streamflow daily oscillation (in summer months in a purely stone bed reaching up to 15%, along with tidal phenomena. The article analyzes one of possible explanations of this effect due to the dependence of the algae thickness layer modifying the channel bed cross-section on the speed of flowing water.

Polymer Electrolytes

Science.gov (United States)

Hallinan, Daniel T.; Balsara, Nitash P.

2013-07-01

This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

Morphology of a Wetland Stream

Science.gov (United States)

Jurmu; Andrle

1997-11-01

/ Little attention has been paid to wetland stream morphology in the geomorphological and environmental literature, and in the recently expanding wetland reconstruction field, stream design has been based primarily on stream morphologies typical of nonwetland alluvial environments. Field investigation of a wetland reach of Roaring Brook, Stafford, Connecticut, USA, revealed several significant differences between the morphology of this stream and the typical morphology of nonwetland alluvial streams. Six morphological features of the study reach were examined: bankfull flow, meanders, pools and riffles, thalweg location, straight reaches, and cross-sectional shape. It was found that bankfull flow definitions originating from streams in nonwetland environments did not apply. Unusual features observed in the wetland reach include tight bends and a large axial wavelength to width ratio. A lengthy straight reach exists that exceeds what is typically found in nonwetland alluvial streams. The lack of convex bank point bars in the bends, a greater channel width at riffle locations, an unusual thalweg location, and small form ratios (a deep and narrow channel) were also differences identified. Further study is needed on wetland streams of various regions to determine if differences in morphology between alluvial and wetland environments can be applied in order to improve future designs of wetland channels.KEY WORDS: Stream morphology; Wetland restoration; Wetland creation; Bankfull; Pools and riffles; Meanders; Thalweg

Dynamical modeling of tidal streams

International Nuclear Information System (INIS)

Bovy, Jo

2014-01-01

I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

Human impacts to mountain streams

Science.gov (United States)

Wohl, Ellen

2006-09-01

Mountain streams are here defined as channel networks within mountainous regions of the world. This definition encompasses tremendous diversity of physical and biological conditions, as well as history of land use. Human effects on mountain streams may result from activities undertaken within the stream channel that directly alter channel geometry, the dynamics of water and sediment movement, contaminants in the stream, or aquatic and riparian communities. Examples include channelization, construction of grade-control structures or check dams, removal of beavers, and placer mining. Human effects can also result from activities within the watershed that indirectly affect streams by altering the movement of water, sediment, and contaminants into the channel. Deforestation, cropping, grazing, land drainage, and urbanization are among the land uses that indirectly alter stream processes. An overview of the relative intensity of human impacts to mountain streams is provided by a table summarizing human effects on each of the major mountainous regions with respect to five categories: flow regulation, biotic integrity, water pollution, channel alteration, and land use. This table indicates that very few mountains have streams not at least moderately affected by land use. The least affected mountainous regions are those at very high or very low latitudes, although our scientific ignorance of conditions in low-latitude mountains in particular means that streams in these mountains might be more altered than is widely recognized. Four case studies from northern Sweden (arctic region), Colorado Front Range (semiarid temperate region), Swiss Alps (humid temperate region), and Papua New Guinea (humid tropics) are also used to explore in detail the history and effects on rivers of human activities in mountainous regions. The overview and case studies indicate that mountain streams must be managed with particular attention to upstream/downstream connections, hillslope

Highly Efficient TADF Polymer Electroluminescence with Reduced Efficiency Roll-off via Interfacial Exciplex Host Strategy.

Science.gov (United States)

Lin, Xingdong; Zhu, Yunhui; Zhang, Baohua; Zhao, Xiaofei; Yao, Bing; Cheng, Yanxiang; Li, Zhanguo; Qu, Yi; Xie, Zhiyuan

2018-01-10

Solution-processed organic light-emitting diodes (s-OLED) consisting of TAPC/TmPyPB interfacial exciplex host and polymer PAPTC TADF emitter are prepared, simultaneously displaying ultralow voltages (2.50/2.91/3.51/4.91 V at luminance of 1/100/1000/1000 cd m -2 ), high efficiencies (14.9%, 50.1 lm W -1 ), and extremely low roll-off rates (J 50 of 63.16 mA cm -2 , L 50 of ca. 15000 cd m -2 ). Such performance is distinctly higher than that of pure-PAPTC s-OLED. Compared to pure-PAPTC, the advanced emissive layer structure of TAPC:PAPTC/TmPyPB is unique in much higher PL quantum yield (79.5 vs 36.3%) and nearly 4-fold enhancement in k RISC of the PAPTC emitter to 1.48 × 10 7 s -1 .

Behaviors of Polymer Additives Under EHL and Influences of Interactions Between Additives on Friction Modification

Science.gov (United States)

Sakurai, T.

1984-01-01

Polymer additives have become requisite for the formulation of multigrade engine oils. The behavior of polymethacrylate (PMA)-thickened oils as lubricants in concentrated contacts under nominal rolling and pure sliding conditions was investigated by conventional optical interferometry. The PMA thickened oils behaved differently from the base oil in the formation of elastohydrodynamic (EHL) films. The higher the elastohydrodynamic molecular weight of the PMA contained in the lubricant, the thinner was the oil film under EHL conditions. The film thickness of shear-degraded PMA-thickened oils was also investigated. The behavior of graphite particles dispersed in both the base oil and the PMA-thickened oil was studied under pure sliding by taking photomicrographs. Many kinds of additives are contained in lubricating oil and the interactions between additives are considered. The interactions of zinc-organodithiophosphates (ZDP) with other additives is discussed.

Polymer compositions, polymer films and methods and precursors for forming same

Science.gov (United States)

Klaehn, John R; Peterson, Eric S; Orme, Christopher J

2013-09-24

Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

How and Why Does Stream Water Temperature Vary at Small Spatial Scales in a Headwater Stream?

Science.gov (United States)

Morgan, J. C.; Gannon, J. P.; Kelleher, C.

2017-12-01

The temperature of stream water is controlled by climatic variables, runoff/baseflow generation, and hyporheic exchange. Hydrologic conditions such as gaining/losing reaches and sources of inflow can vary dramatically along a stream on a small spatial scale. In this work, we attempt to discern the extent that the factors of air temperature, groundwater inflow, and precipitation influence stream temperature at small spatial scales along the length of a stream. To address this question, we measured stream temperature along the perennial stream network in a 43 ha catchment with a complex land use history in Cullowhee, NC. Two water temperature sensors were placed along the stream network on opposite sides of the stream at 100-meter intervals and at several locations of interest (i.e. stream junctions). The forty total sensors recorded the temperature every 10 minutes for one month in the spring and one month in the summer. A subset of sampling locations where stream temperature was consistent or varied from one side of the stream to the other were explored with a thermal imaging camera to obtain a more detailed representation of the spatial variation in temperature at those sites. These thermal surveys were compared with descriptions of the contributing area at the sample sites in an effort to discern specific causes of differing flow paths. Preliminary results suggest that on some branches of the stream stormflow has less influence than regular hyporheic exchange, while other tributaries can change dramatically with stormflow conditions. We anticipate this work will lead to a better understanding of temperature patterns in stream water networks. A better understanding of the importance of small-scale differences in flow paths to water temperature may be able to inform watershed management decisions in the future.

Stream Deniable-Encryption Algorithms

Directory of Open Access Journals (Sweden)

N.A. Moldovyan

2016-04-01

Full Text Available A method for stream deniable encryption of secret message is proposed, which is computationally indistinguishable from the probabilistic encryption of some fake message. The method uses generation of two key streams with some secure block cipher. One of the key streams is generated depending on the secret key and the other one is generated depending on the fake key. The key streams are mixed with the secret and fake data streams so that the output ciphertext looks like the ciphertext produced by some probabilistic encryption algorithm applied to the fake message, while using the fake key. When the receiver or/and sender of the ciphertext are coerced to open the encryption key and the source message, they open the fake key and the fake message. To disclose their lie the coercer should demonstrate possibility of the alternative decryption of the ciphertext, however this is a computationally hard problem.

Active versus passive listening to auditory streaming stimuli: a near-infrared spectroscopy study

Science.gov (United States)

Remijn, Gerard B.; Kojima, Haruyuki

2010-05-01

We use near-infrared spectroscopy (NIRS) to assess listeners' cortical responses to a 10-s series of pure tones separated in frequency. Listeners are instructed to either judge the rhythm of these ``streaming'' stimuli (active-response listening) or to listen to the stimuli passively. Experiment 1 shows that active-response listening causes increases in oxygenated hemoglobin (oxy-Hb) in response to all stimuli, generally over the (pre)motor cortices. The oxy-Hb increases are significantly larger over the right hemisphere than over the left for the final 5 s of the stimulus. Hemodynamic levels do not vary with changes in the frequency separation between the tones and corresponding changes in perceived rhythm (``gallop,'' ``streaming,'' or ``ambiguous''). Experiment 2 shows that hemodynamic levels are strongly influenced by listening mode. For the majority of time windows, active-response listening causes significantly larger oxy-Hb increases than passive listening, significantly over the left hemisphere during the stimulus and over both hemispheres after the stimulus. This difference cannot be attributed to physical motor activity and preparation related to button pressing after stimulus end, because this is required in both listening modes.

Estimation of zirconium in various process streams in molten salt electrorefining process

International Nuclear Information System (INIS)

Suganthi, S.; Vandarkuzhali, S.; Venkatesh, P.; Prabhakara Reddy, B.; Nagarajan, K.

2012-01-01

Molten salt electrorefining process is a non-aqueous pyrochemical process suitable for reprocessing spent metallic fuel. In this process the spent fuel is taken at the anode and the fuel elements are selectively electrotransported to a suitable cathode (either a solid steel cathode or liquid cadmium cathode) using molten LiCl-KCI as electrolyte. We have demonstrated electrorefining of UZr alloy at engineering scale level. 1 Kg U-6%Zr alloy was taken at the anode and pure uranium was recovered at a steel cathode using molten LiCIKCI-5%UCI 3 as electrolyte at 773 K. In this paper we present the method of dissolution, sample preparation and estimation of zirconium in various process streams in the electrorefining experiments carried out in our laboratory

CAMS: OLAPing Multidimensional Data Streams Efficiently

Science.gov (United States)

Cuzzocrea, Alfredo

In the context of data stream research, taming the multidimensionality of real-life data streams in order to efficiently support OLAP analysis/mining tasks is a critical challenge. Inspired by this fundamental motivation, in this paper we introduce CAMS (C ube-based A cquisition model for M ultidimensional S treams), a model for efficiently OLAPing multidimensional data streams. CAMS combines a set of data stream processing methodologies, namely (i) the OLAP dimension flattening process, which allows us to obtain dimensionality reduction of multidimensional data streams, and (ii) the OLAP stream aggregation scheme, which aggregates data stream readings according to an OLAP-hierarchy-based membership approach. We complete our analytical contribution by means of experimental assessment and analysis of both the efficiency and the scalability of OLAPing capabilities of CAMS on synthetic multidimensional data streams. Both analytical and experimental results clearly connote CAMS as an enabling component for next-generation Data Stream Management Systems.

Polymer photovoltaic cells; Etude et realisation de cellules photovoltaiques en polymere

Energy Technology Data Exchange (ETDEWEB)

Sicot, L.

1999-09-29

We study organic photovoltaic cells based on a semiconducting polymer. The first photovoltaic cells we realize are Schottky cells. Their structure are ITO/Polymeric film/Au. Metallic electrode is made of aluminium or gold. The organic layer is made of pure poly(3-butyl-thiophene) or of a blend of the polymer and a dye, the 1,3-bis(di-cyano-methylidene)-2-(4-dibutyl-amino-benzylidene)indane. We study the influence of the nature of the electrode on the conversion efficiency. We also study the variations of the photovoltaic parameters as functions of the thickness of the polymeric film and of the doping ratio of the dye. The performances of this kind of cells depends on the interface between the organic layer and the ITO. Its morphology, particularly its rugosity, and its electrical properties are not easy to control. By depositing a layer of a derivative of perylene on the ITO, we move the photo-generation zone to the interface between the two organic films. The efficiency of this p-n cell is higher than the one measured with the Schottky cell. Nevertheless, we have observed a decrease of the performances of our cells due to the degradation of the dye and the polymer when they are illuminated at high intensity of light during a long time. (author)

Identification and Selection of Major Carbon Dioxide Stream Compositions

Energy Technology Data Exchange (ETDEWEB)

Last, George V.; Schmick, Mary T.

2011-06-30

A critical component in the assessment of long-term risk from geologic sequestration of CO2 is the ability to predict mineralogical and geochemical changes within storage reservoirs due to rock-brine-CO2 reactions. Impurities and/or other constituents selected for co-sequestration can affect both the chemical and physical (e.g. density, viscosity, interfacial tension) behavior of CO2 in the deep subsurface. These impurities and concentrations are a function of both the industrial source(s) of the CO2, as well as the carbon capture technology used to extract the CO2 and produce a concentrated stream for geologic sequestration. This report summarizes the relative concentrations of CO2 and other constituents in exhaust gases from major non-energy related industrial sources of CO2. Assuming that carbon-capture technology would remove most of the incondensable gases N2, O2, and Ar, leaving SO2 and NOx as the main impurities, we selected four test fluid compositions for use in geochemical experiments. These included: 1) a pure CO2 stream representative of food grade CO2 used in most enhanced oil recovery projects: 2) a test fluid composition containing low concentrations (0.5 mole %) SO2 and NOx (representative of that generated from cement production), 3) a test fluid composition with higher concentrations (2.5 mole %) of SO2, and 4) and test fluid composition containing 3 mole % H2S.

Plasticization effect of C60 on the fast dynamics of polystyrene and related polymers: an incoherent neutron scattering study

International Nuclear Information System (INIS)

Sanz, Alejandro; Ruppel, Markus; Cabral, Joao T; Douglas, Jack F

2008-01-01

We utilize inelastic incoherent neutron scattering (INS) to quantify how fullerenes affect the 'fast' molecular dynamics of a family of polystyrene related macromolecules. In particular, we prepared bulk nanocomposites of (hydrogenous and ring-deuterated) polystyrene and poly(4-methyl styrene) using a rapid precipitation method where the C 60 relative mass fraction ranged from 0% to 4%. Elastic window scan measurements, using a high resolution (0.9 μeV) backscattering spectrometer, are reported over a wide temperature range (2-450 K). Apparent Debye-Waller (DW) factors 2 >, characterizing the mean-square amplitude of proton displacements, are determined as a function of temperature, T. We find that the addition of C 60 to these polymers leads to a progressive increase in 2 > relative to the pure polymer value over the entire temperature range investigated, where the effect is larger for larger nanoparticle concentration. This general trend seems to indicate that the C 60 nanoparticles plasticize the fast (∼10 -15 s) local (∼1 A) dynamics of these polymer glasses. Generally, we expect nanoparticle additives to affect polymer dynamics in a similar fashion to thin films in the sense that the high interfacial area may cause both a speeding up and slowing down of the glass state dynamics depending on the polymer-surface interaction

Radiation Synthesis of Superabsorbent Polymers Based on Natural Polymers

International Nuclear Information System (INIS)

Sen, Murat; Hayrabolulu, Hande

2010-01-01

The objectives of proposed research contract were first synthesize superabsorbent polymers based on natural polymers to be used as disposable diapers and soil conditioning materials in agriculture, horticulture and other super adsorbent using industries. We have planned to use the natural polymers; locust beam gum, tara gum, guar gum and sodium alginate on the preparation of natural superabsorbent polymers(SAP). The aqueous solution of natural polymers and their blends with trace amount of monomer and cross-linking agents will be irradiated in paste like conditions by gamma rays for the preparation of cross-linked superabsorbent systems. The water absorption and deswellling capacity of prepared super adsorbents and retention capacity, absorbency under load, suction power, swelling pressure and pet-rewet properties will be determined. Use of these materials instead of synthetic super absorbents will be examined by comparing the performance of finished products. The experimental studies achieved in the second year of project mainly on the effect of radiation on the chemistry of sodium alginate polymers in different irradiation conditions and structure-property relationship particularly with respect to radiation induced changes on the molecular weight of natural polymers and preliminary studies on the synthesis of natural-synthetic hydride super adsorbent polymers were given in details

Polymer and Polymer Gel of Liquid Crystalline Semiconductors

Institute of Scientific and Technical Information of China (English)

Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

2004-01-01

It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

Enhanced performance of dye-sensitized solar cells based on organic dopant incorporated PVDF-HFP/PEO polymer blend electrolyte with g-C3N4/TiO2 photoanode

International Nuclear Information System (INIS)

Senthil, R.A.; Theerthagiri, J.; Madhavan, J.; Murugan, K.; Arunachalam, Prabhakarn; Arof, A.K.

2016-01-01

This work describes the effect of 2-aminopyrimidine (2-APY) on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) blend polymer electrolyte along with binary iodide salts (tetrabutylammonium iodide (TBAI) and potassium iodide (KI)) and iodine (I 2 ) were studied for enhancing the efficiency of the dye-sensitized solar cells (DSSCs) consisting of g-C 3 N 4 /TiO 2 composite as photoanode. The g-C 3 N 4 was synthesized from low cost urea by thermal condensation method. It was used as a precursor to synthesize the various weight percentage ratios (5%, 10% and 15%) of g-C 3 N 4 /TiO 2 composites by wet-impregnation method. The pure and 2-APY incorporated PVDF-HFP/PEO polymer blend electrolytes were arranged by wet chemical process (casting method) using DMF as a solvent. The synthesized g-C 3 N 4 /TiO 2 composites and polymer blend electrolytes were studied and analyzed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The ionic conductivity values of the pure and 2-APY incorporated PVDF-HFP/PEO blend electrolytes were estimated to be 4.53×10 −5 and 1.87×10 −4 Scm −1 respectively. The UV–vis absorption spectroscopy was carried out for the pure and different wt% of g-C 3 N 4 /TiO 2 composites coated FTO films after N3 dye-sensitization. The 10 wt% g-C 3 N 4 /TiO 2 composite film showed a maximum absorption compared to the others. The DSSC assembled with 10 wt% g-C 3 N 4 /TiO 2 as photoanode using the pure polymer blend electrolyte exhibited a power conversion efficiency (PCE) of 3.17% , which was superior than that of DSSC based pure TiO 2 (2.46%). However, the PCE was increased to 4.73% for the DSSC assembled using 10 wt% g-C 3 N 4 /TiO 2 as photoanode with 2-APY incorporated polymer blend electrolyte. Hence, the present study is a successful attempt to provide a new pathway to enhance the performance of DSSCs. - Graphical abstract: In this study, the g-C 3 N

On the importance of PURE - Public Understanding of Renewable Energy

Energy Technology Data Exchange (ETDEWEB)

Broman, Lars; Kandpal, Tara C.

2013-09-15

Public understanding of science (PUS) is a central concept among science communicators. Public understanding of renewable energy (PURE) is proposed as an important sub-concept of PUS. The aim of this paper is to interest and invite renewable energy scientists to join a PURE research project. Four separate important questions for a PURE research project can be identified: (A) Is PURE important? (B) Which issues of PURE are the most important ones, according to renewable energy scientists? (C) What understanding of renewable energy has the general public today, worldwide? (D) How to achieve PURE?.

The Effects of Lithium Triflate (LiCF3SO3) on the PMMA-based Solid Polymer Electrolytes

International Nuclear Information System (INIS)

Chew, K. W.; Chen, S. S.; Pang, W. L.; Tan, C. G.; Osman, Z.

2010-01-01

The effects of Lithium triflate salt (LiCF 3 SO 3 ), on the poly (methyl methacrylate)(PMMA)-based solid polymer electrolytes plasticized with propylene carbonate (PC) solvated in Tetrahydrofuran (THF) have been studied through a.c impedance spectroscopy and infrared spectroscopy. Lithium triflate was incorporated into the predetermined PMMA/PC system that has the highest value of ionic conductivity. In current investigations, four combination systems: Pure PMMA, (PMMA+PC) systems, (PMMA+LiCF 3 SO 3 ) and (PMMA+PC+LiCF 3 SO 3 ) systems were prepared using the solution cast method. Solutions were stirred for numerous hours to obtain a homogenous solution before it is poured into the petri dishes under ambient temperature to form the solid electrolyte thin film. The films were then removed from petri discs and transferred into the dessicator for further drying prior to the different tests. From the characterization done through the a.c impedance spectroscopy, the highest room temperature ionic conductivity in the pure PMMA sample, (PMMA+PC) system and (PMMA+LiCF 3 SO 3 ) system is 2.83x10 -12 Scm -1 , 4.39x10 -11 Scm -1 and 3.93x10 -6 Scm -1 respectively. The conductivity for (PMMA+PC+LiCF 3 SO 3 ) system was obtained with the 30 wt% of lithium triflate, which is 2.48x10 -5 Scm -1 . Infrared spectroscopy shows that complexation occurred between the polymer and the plasticizer, and the polymer and plasticizer and salt. The interactions have been studied in the C=O band, C-O-C band and the O-CH 3 band.

Synthesis and application of molecularly imprinted polymers for the selective extraction of organophosphorus pesticides from vegetable oils.

Science.gov (United States)

Boulanouar, Sara; Combès, Audrey; Mezzache, Sakina; Pichon, Valérie

2017-09-01

The increasing use of pesticides in agriculture causes environmental issues and possible serious health risks to humans and animals. Their determination at trace concentrations in vegetable oils constitutes a significant analytical challenge. Therefore, their analysis often requires both an extraction and a purification step prior to separation with liquid chromatography (LC) and mass spectrometry (MS) detection. This work aimed at developing sorbents that are able to selectively extract from vegetable oil samples several organophosphorus (OPs) pesticides presenting a wide range of physico-chemical properties. Therefore, different conditions were screened to prepare molecularly imprinted polymers (MIPs) by a non-covalent approach. The selectivity of the resulting polymers was evaluated by studying the OPs retention in pure media on both MIPs and non-imprinted polymers (NIP) used as control. The most promising MIP sorbent was obtained using monocrotophos (MCP) as the template, methacrylic acid (MAA) as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker with a molar ratio of 1/4/20 respectively. The repeatability of the extraction procedure and of the synthesis procedure was demonstrated in pure media. The capacity of this MIP was 1mg/g for malathion. This MIP was also able to selectively extract three OPs from almond oil by applying the optimized SPE procedure. Recoveries were between 73 and 99% with SD values between 4 and 6% in this oil sample. The calculated LOQs (between 0.3 and 2μg/kg) in almond seeds with a SD between 0.1 and 0.4μg/kg were lower than the Maximum Residue Levels (MRLs) established for the corresponding compounds in almond seed. Copyright © 2017 Elsevier B.V. All rights reserved.

Bi-orderings on pure braided Thompson's groups

OpenAIRE

Burillo, Jose; Gonzalez-Meneses, Juan

2006-01-01

In this paper it is proved that the pure braided Thompson’s group BF admits a bi-order, analog to the bi-order of the pure braid groups. Ministerio de Educación y Ciencia Fondo Europeo de Desarrollo Regional

Three-dimensional model of corotating streams in the solar wind 3. Magnetohydrodynamic streams

International Nuclear Information System (INIS)

Pizzo, V.J.

1982-01-01

The focus of this paper is two-fold: (1) to examine how the presence of the spiral magnetic field affects the evolution of interplanetary corotating solar wind streams, and (2) to ascertain the nature of secondary large-scale phenomena likely to be associated with streams having a pronounced three-dimensional (3-D) structure. The dynamics are presumed to be governed by the nonlinear polytropic, single-fluid, 3-D MHD equations. Solutions are obtained with an explicit, Eulerian, finite differences technique that makes use of a simple form of artificial diffusion for handling shocks. For smooth axisymmetric flows, the picture of magnetically induced meridional motions previously established by linear models requires only minor correction. In the case of broad 3-D streams input near the sun, inclusion of the magnetic field is found to retard the kinematic steepening at the stream front substantially but to produce little deviation from planar flow. For the more realistic case of initially sharply bounded streams, however, it becomes essential to account for magnetic effects in the formulation. Whether a full 3-D treatment is required depends upon the latitudinal geometry of the stream

Cytoplasmic Streaming in the Drosophila Oocyte.

Science.gov (United States)

Quinlan, Margot E

2016-10-06

Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.

In-stream Physical Heterogeneity, Rainfall Aided Flushing, and Discharge on Stream Water Quality.

Science.gov (United States)

Gomes, Pattiyage I A; Wai, Onyx W H

2015-08-01

Implications of instream physical heterogeneity, rainfall-aided flushing, and stream discharge on water quality control have been investigated in a headwater stream of a climatic region that has contrasting dry and wet seasons. Dry (low flow) season's physical heterogeneity showed a positive correlation with good water quality. However, in the wet season, physical heterogeneity showed minor or no significance on water quality variations. Furthermore, physical heterogeneity appeared to be more complementary with good water quality subsequent to rainfall events. In many cases stream discharge was a reason for poor water quality. For the dry season, graywater inputs to the stream could be held responsible. In the wet season, it was probably the result of catchment level disturbances (e.g., regulation of ephemeral freshwater paths). Overall, this study revealed the importance of catchment-based approaches on water quality improvement in tandem with in-stream approaches framed on a temporal scale.

Stream II-V5: Revision Of Stream II-V4 To Account For The Effects Of Rainfall Events

International Nuclear Information System (INIS)

Chen, K.

2010-01-01

STREAM II-V4 is the aqueous transport module currently used by the Savannah River Site emergency response Weather Information Display (WIND) system. The transport model of the Water Quality Analysis Simulation Program (WASP) was used by STREAM II to perform contaminant transport calculations. WASP5 is a US Environmental Protection Agency (EPA) water quality analysis program that simulates contaminant transport and fate through surface water. STREAM II-V4 predicts peak concentration and peak concentration arrival time at downstream locations for releases from the SRS facilities to the Savannah River. The input flows for STREAM II-V4 are derived from the historical flow records measured by the United States Geological Survey (USGS). The stream flow for STREAM II-V4 is fixed and the flow only varies with the month in which the releases are taking place. Therefore, the effects of flow surge due to a severe storm are not accounted for by STREAM II-V4. STREAM II-V4 has been revised to account for the effects of a storm event. The steps used in this method are: (1) generate rainfall hyetographs as a function of total rainfall in inches (or millimeters) and rainfall duration in hours; (2) generate watershed runoff flow based on the rainfall hyetographs from step 1; (3) calculate the variation of stream segment volume (cross section) as a function of flow from step 2; (4) implement the results from steps 2 and 3 into the STREAM II model. The revised model (STREAM II-V5) will find the proper stream inlet flow based on the total rainfall and rainfall duration as input by the user. STREAM II-V5 adjusts the stream segment volumes (cross sections) based on the stream inlet flow. The rainfall based stream flow and the adjusted stream segment volumes are then used for contaminant transport calculations.

Stream Clustering of Growing Objects

Science.gov (United States)

Siddiqui, Zaigham Faraz; Spiliopoulou, Myra

We study incremental clustering of objects that grow and accumulate over time. The objects come from a multi-table stream e.g. streams of Customer and Transaction. As the Transactions stream accumulates, the Customers’ profiles grow. First, we use an incremental propositionalisation to convert the multi-table stream into a single-table stream upon which we apply clustering. For this purpose, we develop an online version of K-Means algorithm that can handle these swelling objects and any new objects that arrive. The algorithm also monitors the quality of the model and performs re-clustering when it deteriorates. We evaluate our method on the PKDD Challenge 1999 dataset.

LHCb trigger streams optimization

Science.gov (United States)

Derkach, D.; Kazeev, N.; Neychev, R.; Panin, A.; Trofimov, I.; Ustyuzhanin, A.; Vesterinen, M.

2017-10-01

The LHCb experiment stores around 1011 collision events per year. A typical physics analysis deals with a final sample of up to 107 events. Event preselection algorithms (lines) are used for data reduction. Since the data are stored in a format that requires sequential access, the lines are grouped into several output file streams, in order to increase the efficiency of user analysis jobs that read these data. The scheme efficiency heavily depends on the stream composition. By putting similar lines together and balancing the stream sizes it is possible to reduce the overhead. We present a method for finding an optimal stream composition. The method is applied to a part of the LHCb data (Turbo stream) on the stage where it is prepared for user physics analysis. This results in an expected improvement of 15% in the speed of user analysis jobs, and will be applied on data to be recorded in 2017.

The ventral stream offers more affordance and the dorsal stream more memory than believed

NARCIS (Netherlands)

Postma, Albert; van der Lubbe, Robert Henricus Johannes; Zuidhoek, Sander

2002-01-01

Opposed to Norman's proposal, processing of affordance is likely to occur not solely in the dorsal stream but also in the ventral stream. Moreover, the dorsal stream might do more than just serve an important role in motor actions. It supports egocentric location coding as well. As such, it would

The role of remediation, natural alkalinity sources and physical stream parameters in stream recovery.

Science.gov (United States)

Kruse, Natalie A; DeRose, Lisa; Korenowsky, Rebekah; Bowman, Jennifer R; Lopez, Dina; Johnson, Kelly; Rankin, Edward

2013-10-15

Acid mine drainage (AMD) negatively impacts not only stream chemistry, but also aquatic biology. The ultimate goal of AMD treatment is restoration of the biological community, but that goal is rarely explicit in treatment system design. Hewett Fork in Raccoon Creek Watershed, Ohio, has been impacted by historic coal mining and has been treated with a calcium oxide doser in the headwaters of the watershed since 2004. All of the acidic inputs are isolated to a 1.5 km stretch of stream in the headwaters of the Hewett Fork watershed. The macroinvertebrate and fish communities have begun to recover and it is possible to distinguish three zones downstream of the doser: an impaired zone, a transition zone and a recovered zone. Alkalinity from both the doser and natural sources and physical stream parameters play a role in stream restoration. In Hewett Fork, natural alkaline additions downstream are higher than those from the doser. Both, alkaline additions and stream velocity drive sediment and metal deposition. Metal deposition occurs in several patterns; aluminum tends to deposit in regions of low stream velocity, while iron tends to deposit once sufficient alkalinity is added to the system downstream of mining inputs. The majority of metal deposition occurs upstream of the recovered zone. Both the physical stream parameters and natural alkalinity sources influence biological recovery in treated AMD streams and should be considered in remediation plans. Copyright © 2013 Elsevier Ltd. All rights reserved.

Isotopically pure single crystal epitaxial diamond films and their preparation

International Nuclear Information System (INIS)

Banholzer, W.F.; Anthony, T.R.; Williams, D.M.

1992-01-01

The present invention is directed to the production of single crystal diamond consisting of isotopically pure carbon-12 or carbon-13. In the present invention, isotopically pure single crystal diamond is grown on a single crystal substrate directly from isotopically pure carbon-12 or carbon-13. One method for forming isotopically pure single crystal diamond comprises the steps of placing in a reaction chamber a single substrate heated to an elevated diamond forming temperature. Another method for forming isotopically pure single crystal diamond comprises diffusing isotopically pure carbon-12 or carbon-13 through a metallic catalyst under high pressure to a region containing a single crystal substrate to form an isotopically pure single crystal diamond layer on said single crystal substrate

Polymer blend lithography: A versatile method to fabricate nanopatterned self-assembled monolayers

Directory of Open Access Journals (Sweden)

Cheng Huang

2012-09-01

Full Text Available A rapid and cost-effective lithographic method, polymer blend lithography (PBL, is reported to produce patterned self-assembled monolayers (SAM on solid substrates featuring two or three different chemical functionalities. For the pattern generation we use the phase separation of two immiscible polymers in a blend solution during a spin-coating process. By controlling the spin-coating parameters and conditions, including the ambient atmosphere (humidity, the molar mass of the polystyrene (PS and poly(methyl methacrylate (PMMA, and the mass ratio between the two polymers in the blend solution, the formation of a purely lateral morphology (PS islands standing on the substrate while isolated in the PMMA matrix can be reproducibly induced. Either of the formed phases (PS or PMMA can be selectively dissolved afterwards, and the remaining phase can be used as a lift-off mask for the formation of a nanopatterned functional silane monolayer. This “monolayer copy” of the polymer phase morphology has a topographic contrast of about 1.3 nm. A demonstration of tuning of the PS island diameter is given by changing the molar mass of PS. Moreover, polymer blend lithography can provide the possibility of fabricating a surface with three different chemical components: This is demonstrated by inducing breath figures (evaporated condensed entity at higher humidity during the spin-coating process. Here we demonstrate the formation of a lateral pattern consisting of regions covered with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS and (3-aminopropyltriethoxysilane (APTES, and at the same time featuring regions of bare SiOx. The patterning process could be applied even on meter-sized substrates with various functional SAM molecules, making this process suitable for the rapid preparation of quasi two-dimensional nanopatterned functional substrates, e.g., for the template-controlled growth of ZnO nanostructures.

Polymer blend lithography: A versatile method to fabricate nanopatterned self-assembled monolayers.

Science.gov (United States)

Huang, Cheng; Moosmann, Markus; Jin, Jiehong; Heiler, Tobias; Walheim, Stefan; Schimmel, Thomas

2012-01-01

A rapid and cost-effective lithographic method, polymer blend lithography (PBL), is reported to produce patterned self-assembled monolayers (SAM) on solid substrates featuring two or three different chemical functionalities. For the pattern generation we use the phase separation of two immiscible polymers in a blend solution during a spin-coating process. By controlling the spin-coating parameters and conditions, including the ambient atmosphere (humidity), the molar mass of the polystyrene (PS) and poly(methyl methacrylate) (PMMA), and the mass ratio between the two polymers in the blend solution, the formation of a purely lateral morphology (PS islands standing on the substrate while isolated in the PMMA matrix) can be reproducibly induced. Either of the formed phases (PS or PMMA) can be selectively dissolved afterwards, and the remaining phase can be used as a lift-off mask for the formation of a nanopatterned functional silane monolayer. This "monolayer copy" of the polymer phase morphology has a topographic contrast of about 1.3 nm. A demonstration of tuning of the PS island diameter is given by changing the molar mass of PS. Moreover, polymer blend lithography can provide the possibility of fabricating a surface with three different chemical components: This is demonstrated by inducing breath figures (evaporated condensed entity) at higher humidity during the spin-coating process. Here we demonstrate the formation of a lateral pattern consisting of regions covered with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) and (3-aminopropyl)triethoxysilane (APTES), and at the same time featuring regions of bare SiO(x). The patterning process could be applied even on meter-sized substrates with various functional SAM molecules, making this process suitable for the rapid preparation of quasi two-dimensional nanopatterned functional substrates, e.g., for the template-controlled growth of ZnO nanostructures [1].

Dihydroxybenzene/benzoquinone-containing polymers: organic redox polymers

Energy Technology Data Exchange (ETDEWEB)

Moulay, S. [Universite de Blida, Lab. de Chimie-Physique Macromoleculaire, Institut de Chimie Industrielle (Algeria)

2000-08-01

Polymers containing hydroquinone, catechol or their corresponding benzoquinones are a special class of redox polymers. Three pathways of their syntheses are possible: condensation polymerization of suitable monomers, addition polymerization of vinyl monomers containing redox moiety, and chemical attachment of redox unit onto pre-made polymeric matrix. A range of functionalized matrices have been employed such as polyethers, polyesters, polycarbonates, polyurethanes, polyamides and others. Protection of their phenolic functionality has conducted to chemically interesting redox polymer precursors. The presence of a redox moiety coupled with the extant functionalization of the polymer matrix makes the materials very valuable, of wide properties and consequently of vast applicability. For instance, in the oil field, some polymers such as carboxy-methyl-cellulose (CMC) are often applied as to bring about a viscosity improvement and therefore to facilitate the oil drilling. In this regard, Patel evaluated sulfo-alkylated polymeric catechol, namely sulfo-methylated and sulfo-ethylated resins. Indeed, polymeric catechol chemically modified as such exhibited a marked ability to control the viscosity, the gel strength, as well as the filtrate loss of aqueous oil drilling fluids.

High pressure synthesis of zeolite/polymer nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Haines, Julien; Thibaud, Jean-Marc; Rouquette, Jerome; Cambon, Olivier; Di Renzo, Francesco, E-mail: julien.haines@univ-montp2.fr [Institut Charles Gerhardt Montpellier (France); Lee, Arie van der [Institut Europeen des Membranes, Montpellier (France); Scelta, Demetrio; Ceppatelli, Matteo; Dziubek, Kamil; Gorelli, Federico; Bini, Roberto; Santoro, Mario [European Laboratory for Non Linear Spectroscopy, Firenze (Italy)

2016-07-01

Full text: Polymerization of simple organic molecules under high pressure in the subnanometric pores of pure SiO{sub 2} zeolites can be used to produce novel nanocomposite materials, which can be recovered at ambient P and have remarkable mechanical, electrical or optical properties. Polymerization of ethylene in silicalite was studied in situ at high pressure by IR and results in a nanocomposite with isolated chains of non-conducting polyethylene strongly confined in the pores based on single crystal x-ray diffraction data. The nanocomposite is much less compressible than silicalite and has a positive rather than a negative thermal expansion coefficient. In order to target novel electrical and optical properties, isolated chains of conducting polymers can also be prepared in the pores of zeolite hosts at high pressure, such as polyacetylene, which was polymerized under pressure in the pores of the 1-D zeolite TON. The structure of this nanocomposite was determined by synchrotron x-ray powder diffraction data with complete pore filling corresponding to one planar polymer chain confined in each pore with a zig-zag configuration in the yz plane. This very strong confinement can be expected to strongly modify the electrical properties of polyacetylene. In this nanocomposite, our theoretical calculations indicate that the electronic density of states of polyacetylene exhibit van Hove singularities related to quantum 1D confinement, which could lead to future technological applications. This new material is susceptible to have applications in nanoelectronics, nanophotonics and energy and light harvesting. Completely novel nanocomposites were prepared by the polymerization of carbon monoxide CO in silicalite and TON. In these materials, isolated, ideal polycarbonyl chains are obtained in contrast to the non-stoichiometric, branched bulk polymers obtained by high pressure polymerization of this simple system. These poly CO/zeolite composites could be interesting energetic

PSYCHE Pure Shift NMR Spectroscopy.

Science.gov (United States)

Foroozandeh, Mohammadali; Morris, Gareth; Nilsson, Mathias

2018-03-13

Broadband homodecoupling techniques in NMR, also known as "pure shift" methods, aim to enhance spectral resolution by suppressing the effects of homonuclear coupling interactions to turn multiplet signals into singlets. Such techniques typically work by selecting a subset of "active" nuclear spins to observe, and selectively inverting the remaining, "passive", spins to reverse the effects of coupling. Pure Shift Yielded by Chirp Excitation (PSYCHE) is one such method; it is relatively recent, but has already been successfully implemented in a range of different NMR experiments. Paradoxically, PSYCHE is one of the trickiest of pure shift NMR techniques to understand but one of the easiest to use. Here we offer some insights into theoretical and practical aspects of the method, and into the effects and importance of the experimental parameters. Some recent improvements that enhance the spectral purity of PSYCHE spectra will be presented, and some experimental frameworks including examples in 1D and 2D NMR spectroscopy, for the implementation of PSYCHE will be introduced. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The long term response of stream flow to climatic warming in headwater streams of interior Alaska

Science.gov (United States)

Jeremy B. Jones; Amanda J. Rinehart

2010-01-01

Warming in the boreal forest of interior Alaska will have fundamental impacts on stream ecosystems through changes in stream hydrology resulting from upslope loss of permafrost, alteration of availability of soil moisture, and the distribution of vegetation. We examined stream flow in three headwater streams of the Caribou-Poker Creeks Research Watershed (CPCRW) in...

High pressure pure- and mixed-gas separation of CO2/CH4 by thermally-rearranged and carbon molecular sieve membranes derived from a polyimide of intrinsic microporosity

KAUST Repository

Swaidan, Raja

2013-11-01

Natural gas sweetening, one of the most promising venues for the growth of the membrane gas separation industry, is dominated by polymeric materials with relatively low permeabilities and moderate selectivities. One strategy towards improving the gas transport properties of a polymer is enhancement of microporosity either by design of polymers of intrinsic microporosity (PIMs) or by thermal treatment of polymeric precursors. For the first time, the mixed-gas CO2/CH4 transport properties are investigated for a complete series of thermally-rearranged (TR) (440°C) and carbon molecular sieve (CMS) membranes (600, 630 and 800°C) derived from a polyimide of intrinsic microporosity (PIM-6FDA-OH). The pressure dependence of permeability and selectivity is reported up to 30bar for 1:1, CO2:CH4 mixed-gas feeds at 35°C. The TR membrane exhibited ~15% higher CO2/CH4 selectivity relative to pure-gas feeds due to reductions in mixed-gas CH4 permeability reaching 27% at 30bar. This is attributed to increased hindrance of CH4 transport by co-permeation of CO2. Interestingly, unusual increases in mixed-gas CH4 permeabilities relative to pure-gas values were observed for the CMS membranes, resulting in up to 50% losses in mixed-gas selectivity over the applied pressure range. © 2013 Elsevier B.V.

Ageing of cables and new approach for the study of polymer ageing

International Nuclear Information System (INIS)

Monchy-Leroy, C.; Therond, P.

2011-01-01

The study of nuclear cable ageing has become an important subject in particular within the framework of the lifetime extension of nuclear power plants. Until 2000, the approach developed by EDF was a purely empirical one, which establishes from a behavior law, the temporal evolution of a macroscopic property of the jacket or the insulation (generally elongation at break), according to the ageing conditions, such as the temperature and the dose rate. These simulations, coupled with analyses of cables taken on sites after several years of ageing, can demonstrate and justify the good behavior in time of the cables installed in the French nuclear power plants. However from an industrial point of view, this approach, as any empirical approach, is not sustainable and suffers numerous limitations. In particular, the results obtained are not transposable from one industrial formulation to another. That is why for some years, EDF has developed a more generic approach based on the understanding and the modeling of the ageing of polymers by thermo-oxidation and radio-oxidation. This new approach consists of identifying all the occurring reactions at the molecular scale during the polymer ageing. The numerical resolution of the system of differential equations stemming from the scheme of reactions, allows access to the spatial and temporal distributions of the oxidation products formed during the ageing. Today the studies are focused on elastomer matrices of type Polyethylene (PE) and co-polymers of type Ethylene-Propylene-Rubber (EPR) to which were added stabilizers and fillers. Later, the model will allow us to simulate the ageing of any industrial polymer. (authors)

Texture and Microtexture of Pure (6N and Commercially Pure Aluminum after Deformation by Extrusion with Forward-Backward Rotating Die (Kobo

Directory of Open Access Journals (Sweden)

Bieda M.

2016-03-01

Full Text Available Pure aluminium (6N and commercially pure aluminium (99.7 was deformed by KOBO method. Microstructure and texture of both materials after deformation was analyzed by means of scanning and transmission electron microscopy. Advanced methods of crystallographic orientations measurements like Electron Backscatter Diffraction - EBSD (SEM and microdiffraction (TEM was used. Grain size distribution and misorientation between grains in cross and longitudinal sections of the samples were analyzed. Differences in size and homogeneity of the grains were observed in both materials. Pure aluminium was characterized by larger grain size in both sections of extruded material. Whereas commercially pure aluminium reveals smaller grain size and more homogeneous and stable microstructure.

White-light-emitting diode based on a single-layer polymer

Science.gov (United States)

Wang, B. Z.; Zhang, X. P.; Liu, H. M.

2013-05-01

A broad-band light-emitting diode was achieved in a single-layer device based on pure poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine) (PFB). Electromer emission was observed in the red with a center wavelength of about 620 nm in electroluminescence (EL) spectrum. This kind of emission exhibits strong dependence on the thickness of the PFB layer, so that the shape of the EL spectrum may be adjusted through changing the thickness of the active polymer layer to balance between the intrinsic PFB emission in the blue and the electromer emission in the red. Thus, white light emission may be achieved from such a single-layer single-material diode.

Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

Science.gov (United States)

Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

2018-04-01

As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO 2 (PDs-TiO 2 ) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO 4 ) 2 . Under visible light irradiation, the PDs-TiO 2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO 2 is 3.6 and 9.5 times higher than that of pure TiO 2 and commercial P25, respectively. In addition, the PDs-TiO 2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO 2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO 2 , therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method for bonding a thermoplastic polymer to a thermosetting polymer component

NARCIS (Netherlands)

Van Tooren, M.J.L.

2012-01-01

The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting

The Stream-Catchment (StreamCat) Dataset: A database of watershed metrics for the conterminous USA

Science.gov (United States)

We developed an extensive database of landscape metrics for ~2.65 million streams, and their associated catchments, within the conterminous USA: The Stream-Catchment (StreamCat) Dataset. These data are publically available and greatly reduce the specialized geospatial expertise n...

Stream processing health card application.

Science.gov (United States)

Polat, Seda; Gündem, Taflan Imre

2012-10-01

In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data.

Leaf litter processing in West Virginia mountain streams: effects of temperature and stream chemistry

Science.gov (United States)

Jacquelyn M. Rowe; William B. Perry; Sue A. Perry

1996-01-01

Climate change has the potential to alter detrital processing in headwater streams, which receive the majority of their nutrient input as terrestrial leaf litter. Early placement of experimental leaf packs in streams, one month prior to most abscission, was used as an experimental manipulation to increase stream temperature during leaf pack breakdown. We studied leaf...

Polymer Brushes

NARCIS (Netherlands)

Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.

2010-01-01

A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

Diffusion, swelling, cross linkage study and mechanical properties of ZnO doped PVA/NaAlg blend polymer nanocomposite

Science.gov (United States)

Guruswamy, B.; Ravindrachary, V.; Shruthi, C.; Hegde, Shreedatta; Sagar, Rohan N.

2018-04-01

ZnO nano particles were synthesized using a chemical precipitation method. Pure and ZnO nano particle doped PVA-NaAlg blend composite films were prepared using solution casing method. Structural information of these composites was studied using FTIR. Diffusion kinetics of these polymer blend composite were studied using Flory-Huggins theory. Using these diffusion studies, cross-linking density and swelling properties of the films were analyzed. Mechanical properties of these composite are also studied.

Continuum Model for Decontamination of Chemical Warfare Agent from a Rubbery Polymer using the Maxwell-Stefan Formulation

Science.gov (United States)

Varady, Mark; Bringuier, Stefan; Pearl, Thomas; Stevenson, Shawn; Mantooth, Brent

Decontamination of polymers exposed to chemical warfare agents (CWA) often proceeds by application of a liquid solution. Absorption of some decontaminant components proceed concurrently with extraction of the CWA, resulting in multicomponent diffusion in the polymer. In this work, the Maxwell-Stefan equations were used with the Flory-Huggins model of species activity to mathematically describe the transport of two species within a polymer. This model was used to predict the extraction of the nerve agent O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate (VX) from a silicone elastomer into both water and methanol. Comparisons with experimental results show good agreement with minimal fitting of model parameters from pure component uptake data. Reaction of the extracted VX with sodium hydroxide in the liquid-phase was also modeled and used to predict the overall rate of destruction of VX. Although the reaction proceeds more slowly in the methanol-based solution compared to the aqueous solution, the extraction rate is faster due to increasing VX mobility as methanol absorbs into the silicone, resulting in an overall faster rate of VX destruction.

U.S. Department of Energy's initiatives for proliferation prevention in Russia: results of radioactive liquid waste treatment project, year 2

International Nuclear Information System (INIS)

Pokhitonov, Y.; Kamachev, V.; Kelley, D.

2010-10-01

The objective of the project is to engage weapons scientists with training and research programs at selected nuclear sites in Russia and apply high technology polymers to immobilize legacy ILW and HLW liquids that have posed environmental challenges over the years. One compelling advantage of the projects is that V.G. Khlopin Radium Institute and Pacific Nuclear Solutions have been engaged in applied research for seven years to validate the performance and effectiveness of the polymer technology for use with radioactive liquids. With conclusive results of the research work on sixty active and simulant waste streams, the project can focus on actual applications of the technology at Ozersk (Mayak), Sever sk (SCC) Zheleznogorsk (MCC) and Gatchyna rather that on pure research. The long term objective of the project is find viable waste management solutions for serious radioactive and chemical contamination that has existed in Russia and the U. S. for several decades. The polymer technologies may be applied to all radioactive liquid. This paper summarizes the experimental work of the immobilization process and data definition of the most effective polymer compositions in addition to determining the optimum polymer to liquid ratios for economic considerations. (Author)

Stream invertebrate productivity linked to forest subsidies: 37 stream-years of reference and experimental data.

Science.gov (United States)

Wallace, J Bruce; Eggert, Susan L; Meyer, Judy L; Webster, Jackson R

2015-05-01

Riparian habitats provide detrital subsidies of varying quantities and qualities to recipient ecosystems. We used long-term data from three reference streams (covering 24 stream-years) and 13-year whole-stream organic matter manipulations to investigate the influence of terrestrial detrital quantity and quality on benthic invertebrate community structure, abundance, biomass, and secondary production in rockface (RF) and mixed substrates (MS) of forested headwater streams. Using a mesh canopy covering the entire treatment stream, we examined effects of litter ex'clusion, small- and large-wood removal, and addition of artificial wood (PVC) and leaves of varying quality on organic matter standing crops and invertebrate community structure and function. We assessed differences in functional feeding group distribution between substrate types as influenced by organic matter manipulations and long-term patterns of predator and prey production in manipulated vs. reference years. Particulate organic matter standing crops in MS of the treatment stream declined drastically with each successive year of litter exclusion, approaching zero after three years. Monthly invertebrate biomass and annual secondary production was positively related to benthic organic matter in the MS habitats. Rockface habitats exhibited fewer changes than MS habitats across all organic matter manipulations. With leaf addition, the patterns of functional group distribution among MS and RF habitats returned to patterns seen in reference streams. Secondary production per unit organic matter standing crop was greatest for the leaf addition period, followed by the reference streams, and significantly less for the litter exclusion and wood removal periods. These data indicate that the limited organic matter remaining in the stream following litter exclusion and wood removal was more refractory than that in the reference streams, whereas the added leaf material was more labile and readily converted into

Fast acoustic streaming in standing waves: generation of an additional outer streaming cell.

Science.gov (United States)

Reyt, Ida; Daru, Virginie; Bailliet, Hélène; Moreau, Solène; Valière, Jean-Christophe; Baltean-Carlès, Diana; Weisman, Catherine

2013-09-01

Rayleigh streaming in a cylindrical acoustic standing waveguide is studied both experimentally and numerically for nonlinear Reynolds numbers from 1 to 30 [Re(NL)=(U0/c0)(2)(R/δν)(2), with U0 the acoustic velocity amplitude at the velocity antinode, c0 the speed of sound, R the tube radius, and δν the acoustic boundary layer thickness]. Streaming velocity is measured by means of laser Doppler velocimetry in a cylindrical resonator filled with air at atmospheric pressure at high intensity sound levels. The compressible Navier-Stokes equations are solved numerically with high resolution finite difference schemes. The resonator is excited by shaking it along the axis at imposed frequency. Results of measurements and of numerical calculation are compared with results given in the literature and with each other. As expected, the axial streaming velocity measured and calculated agrees reasonably well with the slow streaming theory for small ReNL but deviates significantly from such predictions for fast streaming (ReNL>1). Both experimental and numerical results show that when ReNL is increased, the center of the outer streaming cells are pushed toward the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes.

Lectures on the theory of pure motives

CERN Document Server

Murre, Jacob P; A, Chris

2013-01-01

The theory of motives was created by Grothendieck in the 1960s as he searched for a universal cohomology theory for algebraic varieties. The theory of pure motives is well established as far as the construction is concerned. Pure motives are expected to have a number of additional properties predicted by Grothendieck's standard conjectures, but these conjectures remain wide open. The theory for mixed motives is still incomplete. This book deals primarily with the theory of pure motives. The exposition begins with the fundamentals: Grothendieck's construction of the category of pure motives and examples. Next, the standard conjectures and the famous theorem of Jannsen on the category of the numerical motives are discussed. Following this, the important theory of finite dimensionality is covered. The concept of Chow-K�nneth decomposition is introduced, with discussion of the known results and the related conjectures, in particular the conjectures of Bloch-Beilinson type. We finish with a chapter on relative m...

THE DEVELOPMENT OF THE CALCULATION MODEL FOR THE ESTIMATION OF THE BOILING POINT OF THE ­POLYMER-SOLVENT MIXTURES

Directory of Open Access Journals (Sweden)

Matseevich Andrey Vyacheslavovich

2018-03-01

Full Text Available Subject of the study: one of the most promising areas in the field of polymer physics is the development of the calculation models allowing to quantify the properties of polymers. This work provides the calculation model for the quantitative assessment of the boiling point of solutions of polymer in the organic solvent. The model is based on the chemical structure of polymer and solvent. For the components the Hildebrand solubility parameter, the latent heat of vaporization and the boiling point of the solvent are calculated. Objectives: to generate the equation connecting the boiling point of polymer solution in the chosen solvent with the boiling point of the pure solvent, the molecular weights of the repeating unit of polymer and the molecule of solvent, the weight fraction of polymer in solution, the Hildebrand solubility parameter and the molar volume of the repeating unit of polymer. Materials and methods: the Hildebrand solubility parameter of solutions and polymers and also the van der Waals volume were calculated using the method of A.A. Askadsky; the enthalpy of vaporization of the solvent at the boiling point was expressed through the Hildebrand solubility parameter. The dependence of the enthalpy of vaporization from the temperature was taken into consideration. The computerization of the method was implemented, according to which all calculations are performed automatically after entering the information on the chemical structure of polymer and solvent into the computer. Results: the equation connecting the ebulliometric constant of the low concentration polymer solution with the boiling point of the solvent, the molar volume of the solvent and the Hildebrand parameter was generated. The results of the analysis were checked with regard to the system of polystyrene/toluene; the possibility of practical application of the offered method was shown. Conclusions: the method presented in this article allows to predict the ebulliometric

Selective Gas Permeation in Graphene Oxide-Polymer Self-Assembled Multilayers.

Science.gov (United States)

Pierleoni, Davide; Minelli, Matteo; Ligi, Simone; Christian, Meganne; Funke, Sebastian; Reineking, Niklas; Morandi, Vittorio; Doghieri, Ferruccio; Palermo, Vincenzo

2018-04-04

The performance of polymer-based membranes for gas separation is currently limited by the Robeson limit, stating that it is impossible to have high gas permeability and high gas selectivity at the same time. We describe the production of membranes based on the ability of graphene oxide (GO) and poly(ethyleneimine) (PEI) multilayers to overcome such a limit. The PEI chains act as molecular spacers in between the GO sheets, yielding a highly reproducible, periodic multilayered structure with a constant spacing of 3.7 nm, giving a record combination of gas permeability and selectivity. The membranes feature a remarkable gas selectivity (up to 500 for He/CO 2 ), allowing to overcome the Robeson limit. The permeability of these membranes to different gases depends exponentially on the diameter of the gas molecule, with a sieving mechanism never obtained in pure GO membranes, in which a size cutoff and a complex dependence on the chemical nature of the permeant is typically observed. The tunable permeability, the high selectivity, and the possibility to produce coatings on a wide range of polymers represent a new approach to produce gas separation membranes for large-scale applications.

Porous silicon-cyclodextrin based polymer composites for drug delivery applications.

Science.gov (United States)

Hernandez-Montelongo, J; Naveas, N; Degoutin, S; Tabary, N; Chai, F; Spampinato, V; Ceccone, G; Rossi, F; Torres-Costa, V; Manso-Silvan, M; Martel, B

2014-09-22

One of the main applications of porous silicon (PSi) in biomedicine is drug release, either as a single material or as a part of a composite. PSi composites are attractive candidates for drug delivery systems because they can display new chemical and physical characteristics, which are not exhibited by the individual constituents alone. Since cyclodextrin-based polymers have been proven efficient materials for drug delivery, in this work β-cyclodextrin-citric acid in-situ polymerization was used to functionalize two kinds of PSi (nanoporous and macroporous). The synthesized composites were characterized by microscopy techniques (SEM and AFM), physicochemical methods (ATR-FTIR, XPS, water contact angle, TGA and TBO titration) and a preliminary biological assay was performed. Both systems were tested as drug delivery platforms with two different model drugs, namely, ciprofloxacin (an antibiotic) and prednisolone (an anti-inflammatory), in two different media: pure water and PBS solution. Results show that both kinds of PSi/β-cyclodextrin-citric acid polymer composites, nano- and macro-, provide enhanced release control for drug delivery applications than non-functionalized PSi samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

MEKANISME SEGMENTASI LAJU BIT PADA DYNAMIC ADAPTIVE STREAMING OVER HTTP (DASH UNTUK APLIKASI VIDEO STREAMING

Directory of Open Access Journals (Sweden)

Muhammad Audy Bazly

2015-12-01

Full Text Available This paper aims to analyze Internet-based streaming video service in the communication media with variable bit rates. The proposed scheme on Dynamic Adaptive Streaming over HTTP (DASH using the internet network that adapts to the protocol Hyper Text Transfer Protocol (HTTP. DASH technology allows a video in the video segmentation into several packages that will distreamingkan. DASH initial stage is to compress the video source to lower the bit rate video codec uses H.26. Video compressed further in the segmentation using MP4Box generates streaming packets with the specified duration. These packages are assembled into packets in a streaming media format Presentation Description (MPD or known as MPEG-DASH. Streaming video format MPEG-DASH run on a platform with the player bitdash teritegrasi bitcoin. With this scheme, the video will have several variants of the bit rates that gave rise to the concept of scalability of streaming video services on the client side. The main target of the mechanism is smooth the MPEG-DASH streaming video display on the client. The simulation results show that the scheme based scalable video streaming MPEG- DASH able to improve the quality of image display on the client side, where the procedure bufering videos can be made constant and fine for the duration of video views

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