International Nuclear Information System (INIS)

A kind of polymer-metal complex gel electrolyte is successfully prepared and is used in dye-sensitized solar cells. Raman and X-ray photoelectron spectroscopy confirm the structure of this complex and is found that the metal ion reacts with nitrogen in the polymer. This novel electrolyte shows apparent diffusion coefficient of iodide of 8.37 x 10-7 cm2 s-1 and the energy conversion efficiency of 6.10% when the amount of ZnI2 is 0.04 M. By studying the dissociation active energy of the inorganic salt in electrolytes, we find that the metal salts can dissociate more easily after reacting with polymer and as a result can provide extra free iodide ion. The cell maintains ca. 93% of its initial efficiency after 20 d without further sealing, which shows good long-time stability.

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The lithium carbon batteries studied in this paper use plasticized polymer electrolytes made with passive polymer matrix swollen by a liquid electrolyte with a high ionic conductivity (> 10{sup -3} S/cm at 25 deg. C). The polymers used to prepare the gels are polyacrylonitrile (PAN) and vinylidene poly-fluoride (PVdF). The electrochemical and physical properties of these materials are analyzed according to their composition. The behaviour of solid electrolytes with different materials of lithium ion insertion (graphite and LiNiO{sub 2}) are studied and compared to liquid electrolytes. The parameters taken into account are the reversible and irreversible capacities, the cycling performance and the admissible current densities. Finally, complete lithium ion batteries with gelled electrolytes were manufactured and tested. (J.S.) 2 refs.

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Stearic acid gel is employed to study the phase evolution of MgTiO{sub 3} nanoparticles by thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared. During the preparation of stearic acid gel, tetrabutyl titanate easily absorbed moisture to hydrolyze into Ti(OH){sub 4} firstly, and then reacts with stearic acid and magnesium stearate to form magnesium-titanium oxide network polymer gel, meanwhile n-butanol is generated. When stearic acid gel is calcined in air, a series of oxidation and combustion reactions occur, meanwhile apparent heat is given off. The results show that a metastable intermediate phase Mg{sub 2}TiO{sub 4} is generated at 450 {sup o}C and nearly disappeared at 550 {sup o}C. Simultaneously, a new solid phase of MgTiO{sub 3} appears. The metastable intermediate phase Mg{sub 2}TiO{sub 4} is successfully identified in the current work.

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Viscoelasticity of gel films prepared from solvent-soluble constituents without ash of coal using the mixed solvent of carbon disulfide and N-methyl-2-pyrrolidinone (CS2-NMP) was measured to study the network structure of the constituents. In experiment, Upper Freeport coal and Zao Zhuang coal were used as specimens. Viscoelasticity of various gels with different weight fractions of solvent was measured by creep measurement under a fixed load and stress-strain analysis under variable loads. In the 2nd and 3rd creep measurements, although no large changes in elastic strain and viscoelastic strain were found, viscous strain gradually decreased with an increase in viscosity. In the case of small weight fraction of solvent, small viscous strain and viscoelastic strain were found, while slightly large elastic strain was found. It was thus suggested that this elastic strain is derived from not only physical cross-linked networks by coal-solvent ...

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A solid electrolyte for lithium batteries requires several properties: a good ionic conductivity of about 10{sup -3} S/cm at 298 deg. K, a high cationic transport number (greater than 0.5), a redox stability window higher than 4.5 V, a good stability of the interface with the lithium electrode, and a sufficient mechanical stability. The family of gelled or hybrid electrolytes seems to meet all these requirements. Thus, a systematic study of the gelling of an ethylene carbonate and lithium bistrifluorosulfonimide (LiTFSI) based electrolyte has been carried out. The polymers used for gel or pseudo-gel synthesis are POE, PMMA and PAN which represent 3 different cases of interaction with the electrolyte. All the properties mentioned above have been studied according to the nature of the polymer and to the concentration of lithium salt, showing the advantages and drawbacks of each ...

British Library Electronic Table of Contents (United Kingdom)

Summary: The surface coverage of amorphous silica gels used in the synthesis of silica polyamine composites has been investigated by 29Si NMR. By diluting the polyamine anchor silane, chloropropyl trichlorosilane, with methyl trichlorosilane it was found that surface coverage could be markedly improved for a range of amine polymers after grafting to the silica surface. The commensurate decrease in the number of anchor points and increase in the number of free amines results in an increase in metal capacity and/or an improvement in capture kinetics. Solid state CPMAS-13C NMR has been employed to investigate the structure and metal ion binding of a series of these composite materials. It is reported that the highly branched polymer, poly(ethyleneimine) (PEI) exhibits much broader 13C NMR res...

British Library Electronic Table of Contents (United Kingdom)

The results of following the oxidative degradation of a plastic-bonded explosive (PBX 9501) are reported. Into over 1100 sealed containers were placed samples of PBX 9501 and combinations of its components and aged at relatively low temperatures to induce oxidative degradation of the samples. One of the components of the explosive is a poly(ester urethane) polymer and the oxidative degradation of the samples were following by measuring the molecular weight change of the polymer by gel permeation chromatography (coupled with both differential refractive index and multiangle laser light scattering detectors). Multiple temperatures between 40 and 64 degreeC were used to accelerate the aging of the samples. Interesting induction period behavior, along with both molecular weight increasing (cro...

Energy Technology Data Exchange (ETDEWEB)

Silanization of the silica gel surface in the synthesis of silica gel polyamine composites uses (chloropropyl)-trichlorosilane (CPTCS). It is possible to substitute a molar fraction of reagent CPTCS with methyltrichlorosilane (MTCS), creating a mixed silane surface layer. Two types of silica gels were modified with a series of MTCS:CPTCS molar ratios. Solid-state CP/MAS 29Si and 13C NMR spectroscopies were used to evaluate the surface silane composition. Surface silane coverage was markedly improved for the resulting gels. When polyamines were grafted to the resultant MTCS:CPTCS silane layers, it was shown that the decrease in the number of propyl attachments to the polyamine resulted in increased quantities of ''free amines''. Optimum MTCS:CPTCS ratios were determined for three polyamines grafted onto one silica gel. A substantial free amine ...

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A mesoscopically ordered lamellar gel phase of a polymer-grafted, lipid-based complex fluid is used as a scaffolding to spatially organize inorganic nanoparticles. The complex fluid provides both a highly anisotropic environment and a segregated aqueous and organic domains in which inorganic nanoparticles can be selectively placed by tailoring their size and surface characteristics. Three types of silver nanoparticles -- underivatized, surfactant-stabilized, and dodecanthiol-derivatized -- were evaluated. Comparison of the surface plasmon resonance of the various silver particles dispersed in conventional solvents to those contained within the complex fluid was used to determine the region of spatial localization in the lamellar gel phase. Silver particles rendered hydrophobic by capping with an alkane thiol insert into the hydrocarbon bilayer region. Surfactant-stabilized and underivatized silver nanoparticles reside in ...

International Nuclear Information System (INIS)

The radiation induced reactions in LDPE in the presence of phenolic type antioxidants have been studied. It was shown that various antioxidants can influence the polyethylene network formation and the radical yield in different ways. The dependence of network structure on absorbed doses was determined by gel analysis, hot-set test and extraction of antioxidants for samples irradiated with accelerated electrons. It was found that the antioxidants eluted from polyethylene in higher percentage influence polymer crosslinking to a smaller degree. The ESR studies of #gamma#-irradiated blends of polyethylene with antioxidant indicate the presence of alkyl and phenoxyl radicals. The role of antioxidant molecules on radiation induced reactions in polyethylene-antioxidant systems is considered. The correlation between the network structure and the type of additive in polyethylene is also discussed. (author).

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Porous carbon with high surface area and pore volume was prepared by a reverse replication process and its toluene equilibrium adsorption behavior was investigated. The preparation process of the porous carbon was composed of following sub-processes in series: synthesis and template preparation of silica gel, impregnation and polymerization of DVB monomer in silica template, carbonization of DVB polymer in a silica-polymer composite, and HF-assisted selective etching of silica in carbon-silica composite, The prepared porous carbon was nano porous and had ultrahigh specific surface area (2007 m{sup 2}/g) and large pore volume (3.07cm{sup 3}/g). The nanoporous carbon showed rapid toluene adsorption rate and good toluene adsorption capacity, compared with a commercial Y-type zeolite, In the present study, a reverse replication process to prepare nanoporous carbons will be introduced and its application potential as a gas ...

Science.gov (United States)

... MECHANICAL PROPERTIES, *COPOLYMERS, *SOFT TISSUES, *GELS, *BIOMIMETICS, ISOPRENE, WOUND BALLISTICS, STYRENE PLASTICS ...

J-STORE (Japan)

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porous silica ceramics were prepared(with HCL catalyst)using H{sub 2}O/TEOS molar ratios of 2.6-59.0, with the EtOH/TEOS ratio fixed. After preparing 9 kinds of sol, the followings were investigated; measurement of the gelation time, thermal analyses by TG/DTA, property analyses of the intermediates by FT-IR and X-ray diffractometry with dried samples, analyses of SiO{sub 2} polymer by FT-IR, the investigation of specific surface area and pore size distribution by N{sub 2}-adsorption isotherm, and structural change of SiO{sub 2} polymer and pore morphology by TEM observation, with samples heat-treated to 500 deg. C. In the concentrations of investigated compositions and catalyst, gelation time showed a minimum at ca. 11 moles of water per one mole of TEOS, the highest degree of polymerization at ca.8-18 moles, and the largest specific surface area at ca. 11 moles, which means that the polymerization proceeded fastest at ca. 11 moles of water. ...

Science.gov (United States)

PMID:15557857

International Nuclear Information System (INIS)

(Oct 1974). United Kingdom Bedrosian, PH Sensintaffar, EL Gels, GL

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Sol-gel chemistry has a great many potential applications in the preparation of unique electrochemical materials, from non-equilibrium transition metal oxides which may be of use as high energy density electrodes, to high-surface area mixed oxides which may possess high proton conductivity, to novel composite structures consisting of inorganic gels in combination with organic, electronic, and ionic conductors. This paper reviews prior work on proton conduction in gel systems and presents recent work regarding electrode materials prepared by sol-gel methods and inorganic-organic materials.

KoreaScience (Korea)

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J-STORE (Japan)

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A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor. 3 figs.

UK PubMed Central (United Kingdom)

Protein modifications such as phosphorylation are often studied by two-dimensional gel electrophoresis since the perturbation in the protein’s pI value is readily detected by this method....Full Text Available

UK PubMed Central (United Kingdom)

The cerebrospinal fluid (CSF) from 115 consecutive patients undergoing diagnostic lumbar puncture or myelography was examined to determine the usefulness of immunofixation, following agarose gel electrophoresis,...Full Text Available

UK PubMed Central (United Kingdom)

Software for gel image analysis and base-calling in fluorescence-based sequencing consisting of two primary programs, BaseFinder and GelImager, is described. BaseFinder is a framework for trace processing,...Full Text Available

International Nuclear Information System (INIS)

One-dimensional core-shell polymer nanowires offer many advantages and great potential for many different applications. In this paper we introduce a highly versatile two-step template wetting process to fabricate two-component core-shell polymer nanowires with controllable shell thickness. PLLA and PMMA were chosen as model polymers to demonstrate the feasibility of this process. Solution wetting with different concentrations of polymer solutions was used to fabricate the shell layer and melt wetting was used to fill the shell with the core polymer. The shell thickness was analyzed as a function of the polymer solution concentration and viscosity, and the core-shell morphology was observed with TEM. This paper demonstrates the feasibility of fabricating polymer core-shell nanostructures using our two-step template wetting process and opens ...

Science.gov (United States)

Some bacteria move inside cells by recruiting the actin filaments of the host cells. The filaments are polymerized at the back surface of the bacteria, and they move away, forming a "comet" tail behind the bacterium, which consists of gel network. We develop a one-dimensional mathematical model of the gel based on partial differential equations which involve the number of filaments, the density and velocity of the gel, and the pressure. The two end-points of the gel form two free boundaries. The resulting free boundary problem is rather non-standard. We prove local existence and uniqueness.

Science.gov (United States)

... Descriptors : *Combustible cartridge cases, *Water repellents, *Protective coatings, *Patents, Silica gel, Aluminum compounds, Binders ...

Energy Technology Data Exchange (ETDEWEB)

The polymer industry is a young industry that has undergone tremendous growth and change over the last sixty years. Many important discoveries in polymer science have been accidental. Most of the learning has been by trial and error and most of the understanding is still basically empirical--make a polymer material or compound and then put it to the test to study what it is and how it performs. This article provides an overview of what polymers and polymer compounds are, why they behave as they do, and it discusses several examples of failures of rubber and plastic components.

British Library Electronic Table of Contents (United Kingdom)

N-doped TiO2 has been prepared by use of sol?gel systems containing titanium alkoxide, with nitric acid as the nitrogen source. The time needed for gelation of the systems was drastically reduced by ultrasonic irradiation. The peaks assigned to the nitrate and nitrous ions were observed by FT-IR measurement during the sol?gel reaction. The N-doping was confirmed by the observation of N?O peaks in the XPS spectrum of the sample heated at 400??C. The nitrate ion acted as an oxidizer of the ethanol solvent and titanium species. The TiO2 became doped with nitrogen oxide species as a result of reduction of nitrate ion incorporated into the dried gel samples. These results indicated that the added nitric acid was reduced during the sol?gel transition and heating process, and the resulting NO spe...

Science.gov (United States)

... Title : Wear Rate and Friction Coefficient in Liquid Nitrogen and Hydrogen of Steel Sliding on Polymer Laminates (Various Fabrics and Polymers. ...

UK PubMed Central (United Kingdom)

Synthetic polymers and nanomaterials display selective phenotypic effects in cells and in the body that affect signal transduction mechanisms involved in inflammation, differentiation, proliferation,...Full Text Available

KoreaScience (Korea)

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British Library Electronic Table of Contents (United Kingdom)

The effect of the moisture content in amorphous polymers (PS, PVC, PMMA) on their electro-physical properties is considered. Analytical relationships describing the inflence of the external-field frequency and environmental relative humidity on the conductivity of the polymers are given. For the use of these polymers as active elements of moisture sensors, the moisture-resistive effect is estimated.

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

A wood-polymer composite has been produced by impregnating the wood with the monomer and subsequently polymerizing it by exposure to a gamma radiation source. To compare the improvement in creep deformation of the wood due to the polymer impregnation, a nonlinear Norton-Bailey isothermal mathematical function has been used to model the bending creep deformation of the wood-polymer composites. Results show that the impregnation significantly improves the creep resistance of the wood. The maximum creep resistance is obtained when the amount of polymer impregnation exceeds about 30%. An interfacial interaction between the wood cell wall and the polymer could explain the creep deformation improvement, as well as the maximum impregnation level beyond which little improvement occurs. The results indicate that polymer impregnation is a viable method for improving the ...

International Nuclear Information System (INIS)

The thermal properties of five types of radiation-induced wood-polymer composites based on a tropical hardwood, rubberwood (Hevea braziliensis), was studied by oxygen index measurement, differential thermal analysis (DTA) and thermogravimetry (TG). The DTA and TG curves of composites were different from those of rubberwood, which can be attributed to the presence of the incorporated polymers. Of the five composites, the one impregnated with bis(2-chloroethyl)vinyl phosphonate reduced the initial temperature of decomposition, increased the peak temperatures of exothermic reactions, and increased the char yield. Comparison with physical blends of rubberwood and the corresponding polymer provided some evidence of chemical interaction of wood and polymer in some of the composites. (author).

International Nuclear Information System (INIS)

Polymerizing effects of high energy radiation has been found suitable for preparation of wood-polymer composites. In the present work after evaluating polymer products that have been obtained by irradiation method, wood-polymer composites have been prepared by in situ polymerization of vinyl acetate, acrylic acid and acrylic acid/styrene mixture using two samples of Iranian hardwoods, Beech and Hornbeam. These woods and their composites have been tested for their physical and mechanical properties. The results have shown that chemical bonding between polymer and the cell wall component lead to better strength properties in the composites. (author).

International Nuclear Information System (INIS)

A wood/polymer composite was produced by impregnating Ramin wood with methyl methacrylate monomer and subsequently polymerizing it by gamma irradiation. To assess the improvement in compression strength of the wood caused by the polymer impregnation, a microbuckling compression failure mechanism was used to model the compression failure of the composite. Such a mechanism was found to predict a linear relationship between the compression strength and the percentage polymer impregnation (by weight). Uniaxial compression test results at 45(#+-#5)% and 90(#+-#5)% relative humidity levels, after being statistically analysed, showed that such a linear relationship was valid for up to 100% polymer impregnation. (author).

British Library Electronic Table of Contents (United Kingdom)

In this work, a new sol-gel auto-combustion method has been performed to synthesize single phase nickel ferrite nanocrystalline powders by using n-cetyltrimethylammonium bromide, as a cationic surfactant. The gels were prepared from ferric and nickel nitrates and citric acid. Ammonia was used as pH adjusting agent as well. The effects of the surfactant on the after combustion calcination process and the reduction of the resulting powder crystallite size which affects the magnetic properties of the material were investigated by XRD and DTA/TGA techniques. The results showed that the ignition of the gels in air have a self-propagating behavior. Addition of surfactant to the starting solution affected the crystallite size of the synthesized powders and their phase constitution. The crystallit...

Science.gov (United States)

PMID:11004287

British Library Electronic Table of Contents (United Kingdom)

In this project, nanocrystalline SnO2 powders were successfully prepared by (a) citrate sol-gel and (b) direct precipitation methods. Powders were characterized using thermal analysis techniques (DTA-TG-DSC), X-ray powder Diffraction (XRD), surface area (BET) and electrical conductivity measurements. XRD patterns showed the presence of the cassiterite structure. SnO2 particles, prepared through sol-gel method exhibit crystallite sizes in the range from 3.1 to 22.3 nm when the gel is heat treated at different temperatures up to 900?C. SnO2 nanocrystallites prepared by the precipitation method are comparatively larger in size. The higher specific surface area was obtained for the powder prepared using sol-gel method and the obtained average grain size (d) is relatively large compared with th...

Wastenet

...Polymer Fuel Cells Challenge Publications News Events Login Register Search Content type All Web pages Case studies Publications News Video Home ...Buildings Carbon capture & storage Combined heat & power Electricity transmission & distribution Energy storage Fuel cells Geothermal Hydroelectric Hydrogen Industry Lighting Marine Metering Nuclear Solar Transport Wind ...Home Emerging technologies Current focus areas Polymer Fuel Cell Challenge Polymer Fuel Cells Challenge The objective of the Polymer Fuel Cells Challenge is to develop,...prove and commercialise novel polymer fuel cell technologies that have the potential to deliver a step-change in overall system cost. What are ...

Energy Technology Data Exchange (ETDEWEB)

The entrapment of proteins using the sol-gel route provides a means to retain its native properties and artificially reproduce the molecular crowding and confinement experienced by proteins in the cell allowing investigation of the physico-chemical and structural properties of biomolecules at the biotic/abiotic interface. The biomolecules are spatially separated and 'caged' in the gel structure but solutes can freely permeate the matrix. Thus, properties such as the folding of ensembles of individual molecules can be examined in the absence of aggregation effects that can occur in solution studies. Green fluorescent protein from Aequorea coerulescens was used as a model protein to examine the unfolding/re-folding properties of protein in silica gels. The recombinant protein was isolated and purified from Escherichia coli extracts by cell lysis, three-phase partitioning, dialysis, and anion exchange ...

Energy Technology Data Exchange (ETDEWEB)

SiO{sub 2}, TiO{sub 2} and AlO(OH) powders obtained by the sol-gel method were investigated by transmission electron microscopy. The mass-radius relation was used to determine the fractal dimensions from the images. These fractal dimensions were corrected in order to obtain the powder fractal dimensions. The results indicate a good fractal behavior and high fractal dimensions.

Energy Technology Data Exchange (ETDEWEB)

Tannin gel particles that have extremely high adsorption capacity for hexavalent chromium Cr(VI) have been developed by controlling gelation of Mimosa tannin extracted from the bark of plants. The gelation process is composed of two stages; partial gelation of Mimosa tannin by reaction with formaldehyde (cross-linking agent) and granulation by dispersing the partially gelated solution into a liquid mixture of decalin ad a polyether nonionic surfactant with vigorous stirring. The structure of the tannin gel particles is controlled by a combination of operating conditions such as reaction time and temperature at both stages. The water content of the tannin gel particles that reflects their structure can be widely changed from 40 to 79 %(wet basis), even for a constant composition of 23 g Mimosa tannin and 6 ml formaldehyde (37 wt %). It is found that it is very important to increase the water content without losing mechanical ...

International Nuclear Information System (INIS)

Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO_3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy obtained for hydrolysis reaction was Q_c_h_e = 56.07 kJ/mole. The diffusion coefficient of the Pb ions from the gel layer was determined by using its concentration in solution and in LSG. The shrinkage of the sample and ...

UK PubMed Central (United Kingdom)

The main aim of the present study was to evaluate potential of ternary complexation (comprising of drug, cyclodextrin and polymer) as an approach for taste masking. For this purpose famotidine with...Full Text Available

UK PubMed Central (United Kingdom)

A variety of albumin polymers were prepared and tested for binding with hepatitis B surface antigen (HBsAg): synthetic polymers cross-linked by either glutaraldehyde or carbodiimide; heat-aggregated...Full Text Available

Science.gov (United States)

The present article studies the electret state of polymers when moving through an alternating-current corona discharge plasma and investigates means for the determination of the transition of the polymeric material from the initial state of the electret when the corona-displaying voltage is increased.

Science.gov (United States)

... spatially defined fashion. Many surface modification techniques require a sequential chemical treatment of the surface.6 ...

International Nuclear Information System (INIS)

English 2006 2 p. Brazil Rocha, RM Centro Tecnico Aeroespacial, Sao

Medline Plus

... ever get in this slide. This is basically mechanical properties of the polyuretha urethane polymer called Bioflex versus ...

Science.gov (United States)

... Accession Number : ADA546034. Title : Fluoroalkyl Polyhedral Oligomeric Silsesquioxane (F-POSS) Based Monomers and Polymers. ...

International Nuclear Information System (INIS)

The compressive and bending strengths of a local tropical wood (Kapur-Dryobalanop sp.) were improved significantly by suitable impregnation of polymeric monomers (methylmethacrylate, methylmethacrylate - 5% dioxane and vinyl acetate) into the wood cellular structure and subsequent irradiation to form a wood-polymer composite. Statistical analysis revealed a linear relationship between increase in the strengths and the percentage of polymer impregnated. Fractographic analysis of the impact fractured surfaces under the scanning electron microscope showed the nature of the wood-polymer interface, which could account for the increase in the compressive and bending strengths. (author).

Science.gov (United States)

... Descriptors : *Combustible cartridge cases, *Polymers, *Test equipment, *Patents, Combustion chambers, Breech mechanisms, Gas generating ...

Science.gov (United States)

FEP polyethylene mechanical properties affected by UV. " Siloxane-modified materials resist AO. " Nonsilicone polymers attacked by AO ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents ionic conductivity results obtained with polymer electrolytes and also with propylene carbonate solutions. The domain of electrochemical activity of this salt has been determined using cycle volt-amperometry in propylene carbonate. Preliminary experiments on the stability of the polymer electrolyte with respect to the lithium electrode have been carried out for a possible subsequent use in lithium batteries. (J.S.) 4 refs.

Energy Technology Data Exchange (ETDEWEB)

Interpenetrated lattices (IPL) are combinations of reticulated polymers linked together by permanent crisscross. This structure is well-adapted to combined highly incompatible pairs of polymers. The in-situ sequential method has been applied successfully to the synthesis of ethylene poly-oxides / poly-siloxanes IPLs. The results concerning the preparation of such lattices and their behaviour as solid polymer electrolytes are presented in this paper. (J.S.) 24 refs.

Energy Technology Data Exchange (ETDEWEB)

The dual characteristics in the performance of polymers in wood-polymer composites systems have been pursued with regard to the resolution of mechanical anisotropy of wood and the improvement in dimensional stability. The objective of the present study is to pursue the polymerization mechanism in wood under electron beam irradiation and the temperature dependence of polymer-wood interactions induced at various levels of higher order structure of wood in order to understand the polymer performance. Veneers used in the study were of rotary-cut beech (Fagus crenata Blume) 0.65 mm thick. All samples were oven-dried in vacuo at 80/sup 0/C for 30 hr. The monomers used in the study were methyl methacrylate, styrene, acrylic acid, acrylonitrile, and unsaturated polyester. Experimental details are given. Results are given and discussed.

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The primary aim of this project is to obtain a basic scientific understanding of electrical transport processes at interfaces that contain an organic electronic material. Because of their processing advantages and the tunability of their electronic properties, organic electronic materials are revolutionizing major technological areas such as information display. We completed an investigation of the fundamental electronic excitation energies in the prototype conjugated polymer MEH-PPV. We completed a combined theoretical/experimental study of the energy relation between charged excitations in a conjugated polymer and the metal at a polymer/metal interface. We developed a theoretical model that explains injection currents at polymer/metal interfaces. We have made ...

British Library Electronic Table of Contents (United Kingdom)

In this study a novel sol-gel auto-combustion method, using n-decyltrimethylammonium bromide as a cationic surfactant, has been used to synthesize strontium hexaferrite nanocrystalline powder. The dried nitrate-citrate gel, prepared from a solution of ferric nitrate, strontium nitrate, citric acid, trimethylamine and cationic surfactant, exhibited an auto-combustion behavior after ignition in air. The formation reaction temperature, phase identification, crystallites size, particles size distribution and morphology of resultant strontium hexaferrite powder were investigated by DTA/TGA, FTIR, XRD, LPSA, TEM and SEM techniques. The results showed that in presence of the cationic surfactant, the combustion intensity increases and the crystallite size decreases. The crystallite size of stronti...

Energy Technology Data Exchange (ETDEWEB)

Step-scan Fourier transform infrared spectroscopy in conjunction with impulse stress on polymer films has been used to monitor dynamic rheological responses in real time. A novel piezo-electrically-driven polymer microrheometer was employed to apply repetitive impulses to the polymer sample while time-domain spectra were recorded. Recent results include the study of both semi-crystalline polymers such as isotactic polypropylene (iPP) and elastomers such as Estane polyester/polyurethane copolymer and Kraton tri-block copolymer. The spectral changes of iPP are consistent with frequency-domain results. For iPP at room temperature, large differences in the response times of different absorption bands are not seen. However, the orientation response of the CH{sub 3} rocking mode is slightly slower than the responses of the backbone modes. To the authors` knowledge, this is the first reported successful ...

International Nuclear Information System (INIS)

In this study nanocrystalline powders of yttria-stabilized zirconia (ZrO_2-8Y_2O_3) have been synthesized through 'polymerized complex method'. Zirconium chloride, yttrium nitrate, citric acid and ethylene glycol were polymerized at 80 "oC to produce a gel-like mass in which metallic ions were uniformly distributed. During the thermal treatment of dried gel, nanocrystalline powder was formed at 450 "oC and 650 "oC for 2 h. Thermal reactions and crystalline phase formation of the dried gel were investigated through thermal analysis and X-ray diffraction analysis, respectively. The results of thermal analysis and XRD showed the formation of nanocrystalline powder at less than 600 "oC. Chemical bonding of the dried gel was investigated by Fourier transform infrared spectroscopy analysis. Morphology of powder calcined at 650 "oC was analyzed by scanning electron microscope. Yttria-stabilized zirconia ...

Science.gov (United States)

PMID:19922877

UK PubMed Central (United Kingdom)

Polyamine oxidase was purified to homogeneity from leaves of water hyacinth by the criterion of sodium dodecyl sulfate gel electrophoresis (SDS disc PAGE). The enzyme showed a high specificity for spermidine...Full Text Available

UK PubMed Central (United Kingdom)

Although two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) has been used as the standard proteomic approach for separating proteins in a complex mixture, this technique has many drawbacks....Full Text Available

UK PubMed Central (United Kingdom)

A lentivirus was isolated from 2 goats in Mexico that were seropositive to caprine arthritis encephalitis virus (CAEV) by the agar gel immunodiffusion (AGID) test. The lentivirus was identified as CAEV...Full Text Available

International Nuclear Information System (INIS)

Reduction of occupational radiation exposure dose in a BWR plant is achieved by an elimination of crud in a BWR primary loop condensate stream by condensate demineralizer. Crud removal by condensate polisher improves year by year, a phenomenon called the Aging Effect of Ion Exchange Resins. The cause of this phenomenon is assumed to be mainly due to changes in the cation resin property becoming more crud adsorptive, where a typical change in physical property of aged cation resin is an increase in water retention capacity. Assuming that the crud removal efficiency was influenced by a crosslinkage of cation resin, an attempt was made to enhance this removal efficiency by decreasing the crosslinkage and satisfactory results were obtained. As a result, new gel type cation resins were developed with lower crosslinkage and larger surface areas, as compared with conventional gel type resins. The crosslinkage degree of these new cation resins are ...

UK PubMed Central (United Kingdom)

Ethylene rapidly and transiently up-regulates the activity of several monomeric GTP-binding proteins (monomeric G proteins) in leaves of Arabidopsis as determined by two-dimensional gel electrophoresis...Full Text Available

UK PubMed Central (United Kingdom)

A pigment-dispersing hormone (PDH) from eyestalks of the fiddler crab Uca pugilator has been purified by gel filtration, ion-exchange chromatography, partition chromatography, and reversed-phase...Full Text Available

UK PubMed Central (United Kingdom)

1. ATP sulphurylase from Saccharomyces cerevisiae was purified 140-fold by using heat treatment, DEAE-cellulose chromatography and Sepharose 6B gel filtration. 2. The enzyme was stable...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The gel electrolyte for the zinc-air cell was prepared by mixing hydroponics gel with a 6M potassium hydroxide aqueous solution. The self-discharge of cells was characterized by measuring the open-circuit voltage. The effect of a discharge rate of 50mA constant current on cell voltage and plateau hour, as well as the voltage-current and current density-power density were measured and analysed. The electrode degradation after discharge cycling was characterized by structural and surface methods. The oxidation of the electrode surface further blocked the utilization of the Zn anode and was identified as a cause for the failure of the cell. (author)

Science.gov (United States)

The effects of a timolol maleate gel-forming solution (TMGS) on intraocular pressure (IOP), blood pressure (BP), and pupil size (PS) were evaluated in normotensive dogs. TMGS was administered once daily to six normotensive beagle dogs. TMGS administration reduced IOP and PS. The hypotensive effect persisted for 24 hr after the administration. The mean reduction in IOP was 5.3 mm Hg (P<0.01). The changes in BP and PS were not significant. These results suggest that TMGS can potentially be used in the treatments of glaucoma and ocular hypertension in dogs. PMID:16820724

British Library Electronic Table of Contents (United Kingdom)

In this research a sol-gel auto-combustion route has been proposed to synthesize strontium hexaferrite nanopowder, using metal nitrates, ammonia as pH adjusting agent, n-decyltrimethylammonium bromide as a cationic surfactant and different fuels such as citric acid, glycine, acetylacetone and oxalic acid. The formation temperature of strontium hexaferrite and its crystallite size in presence of different fuels were compared together. The results showed the lowest formation temperature as well as the smallest crystallite size in the presence of citric acid as 900degreeC and 37.3nm respectively.

International Nuclear Information System (INIS)

Complimentary spectroscopic, microscopic and electrochemical studies were performed to characterise the barrier properties as well as the interface structure of model iron substrates covered with thin plasma polymer films. Cathodic plasma polymers were deposited which show high barrier properties. The metal surface was pre-treated by a reducing or oxidising plasma. This allowed the adjustment of the oxidation state of the interface layer. The interface structure was characterised by means of X-ray photoelectron sputter profiles, infrared spectroscopy and the application of a Kelvin probe. The investigations show that the measured Voltapotential on the plasma polymer surface can be correlated with the oxidation state of the interface. Reducing plasmas lead to an almost oxide free surface. After deposition of the plasma polymer, this reduced state of the oxide is sensitive to re-oxidation of the interface ...

Energy Technology Data Exchange (ETDEWEB)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after ...

Energy Technology Data Exchange (ETDEWEB)

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4, LiCoO.sub.2, LiNiO.sub.2 and LiV.sub.2 O.sub.5 and their derivatives.

Energy Technology Data Exchange (ETDEWEB)

Researchers are developing polymer-based coating systems to reduce scaling and corrosion of air-cooled condensers that use a geothermal fluid spray for heat transfer augmentation. These coating systems act as barriers to corrosion to protect aluminum fins and steel tubing; they are formulated to resist the strong attachment of scale. Field tests have been done to determine the corrosion and scaling issues related to brine spraying and a promising organometallic polymer has been evaluated in salt spray tests.

Energy Technology Data Exchange (ETDEWEB)

Fractal dimensional analysis was employed to obtain a quantitative measure of the morphology of polymer networks formed by UV irradiation induced polymerization of photo-reactive mesogenic monomers dissolved in a liquid crystal host medium. The fractal dimensions obtained, may be interpreted by polymer network growth following a percolation-like model for monomer concentrations well below the solubility limit. On passing the solubility limit, the polymerization process changes from a (radical chain) solution polymerization to a dispersion polymerization, with fractal dimensions decreasing and suggesting a cluster-cluster aggregation process for monomer concentrations above the solubility limit, similar to the aggregation of colloidal particles.

International Nuclear Information System (INIS)

The effect of additives on the grafting of a monomer, butylmethacrylate (BA), into simul (a soft wood) has been studied using "6"0Co source at 3 Mrad. The enhancement of polymer loading (grafting) by the addition of minute amounts (1%) of oligomers and of polyfunctional monomers into simul + BA system has been further increased in the presence of acid and urea. The synergistic polymer loading yields by acid addition cause substantial decrease of tensile strength values of wood-plastic composite; but urea increases both polymer loading and tensile strength values synergistically in these systems. (author).

UK PubMed Central (United Kingdom)

Axon outgrowth and guidance to the proper target requires the coordination of filamentous (F)-actin and microtubules (MTs), the dynamic cytoskeletal polymers that promote shape change and locomotion....Full Text Available

UK PubMed Central (United Kingdom)

The rejection thresholds of Phormia regina Meigen for twenty-four glycols have been determined. A definite relationship between the concentration of the test material and the distribution...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the ...

Science.gov (United States)

... Accession Number : ADD014577. Title : Phthalonitrile Monomers Containing Imide and/or Phenoxy Linkages, and Polymers Thereof. ...

International Nuclear Information System (INIS)

A poly(ether urethane) (PEUR)/poly(ethylene oxide) (PEO)/SiO2 based nanocomposite polymer is prepared and employed in the construction of high efficiency all-solid-state dye-sensitized nanocrystalline solar cells. The introduction of low-molecular weight PEUR prepolymer into PEO electrolyte has greatly enhance the electrolyte performance by both improving the interfacial contact properties of electrode/electrolyte and decreasing the PEO crystallization, which were confirmed by XRD and SEM characteristics. The effects of polymer composition, nano SiO2 content on the ionic conductivity and I3- ions diffusion of polymer-blend electrolyte are investigated. The optimized composition yields an energy conversion efficiency of 3.71% under irradiation by white light (100 mW cm-2).

International Nuclear Information System (INIS)

English 2004 2 p. Brazil Rocha, RM Centro Tecnico Aeroespacial (CTA),

KoreaScience (Korea)

Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Abstract The effects of the type of coupling agent and virgin polypropylene (PP) content on the mechanical properties and water absorption behavior of recycled low-density polyethylene/wood flour (WF) composites were investigated. The fractured surfaces of these recycled wood/plastic composites (rWPCs) were examined to gain insight into the distribution and dispersion of WF within the polymer matrix. The results indicate that the use of 100% recycled polymer led to inferior mechanical properties and to a greater degree of moisture absorption and swelling when compared to recycled polymer-virgin PP wood/plastic composites. This could have been related to the poor melt strength and inferior processability of the recycled polymer. The extent of improvement of the mechanical properties depende...

British Library Electronic Table of Contents (United Kingdom)

Wood plastic composites (WPCs) are comprised of wood flour and thermoplastic polymer. The matrix is typically high-density polyethylene, poly (vinyl chloride), or polypropylene. The effect of morphology and micromechanics of wood flour particles on the mechanical performance of the bulk composite is a relatively unexplored area. The knowledge about the in situ properties of wood particles and the interfacial properties between the wood particles and the polymer matrix in the bio-composites is very limited. The objective of this work is to characterize the full-field deformation and strain distribution in and around wood particles embedded in polymer matrix. The mechanical tests are performed in small-scale tensile loading stage on thin composite samples containing 1-3 wood particles orient...

Energy Technology Data Exchange (ETDEWEB)

Since several years we apply the radiation-grafting technique to prepare polymeric membranes for application in polymer electrolyte fuel cells (PEFCs). Our investigations presented here focus on changes in toughness of these materials after the various synthesis steps and the importance of membrane toughness for their application in PEFCs. (author) 2 figs., 4 refs.

International Nuclear Information System (INIS)

Esters of dihydric alcohols with alkenylphosphonic or alkenylphosphinic acids which are polymerizable by free radicals are described. They are combined with polymer binders, in particular water-soluble polymers, and photoinitiators forming free radicals to give photopolymerizable mixtures which are suitable for the production of photoresists and printing plates. The mixtures display low heat-sensitivity and have long shelf lives. (author) 1 tab.

British Library Electronic Table of Contents (United Kingdom)

The physics and technology of a new class of efficient composite piezoelectrics are described. This material combines nanostructured and micropiezoelectric matrix composites. They consist of a polymer matrix, an insulating nanodimensional phase, and a microdimensional piezoelectric phase. It is shown that the nanostructuring of the near-surface region of polymer-PZT piezoelectric composites greatly improves their piezoelectric, mechanical, and electromechanical characteristics. A plausible mechanism underlying this effect is suggested.

Energy Technology Data Exchange (ETDEWEB)

Water transport in the ionomeric membrane, typically Nafion{reg_sign}, has profound influence on the performance of the polymer electrolyte fuel cell, in terms of internal resistance and overall water balance. In this work, high resolution neutron imaging of the Nafion{reg_sign} membrane is presented in order to measure water content and through-plane gradients in situ under disparate temperature and humidification conditions.

International Nuclear Information System (INIS)

Radiation processed wood-polymer composites (WPC) can replace conventional wood in many industrial applications. However, for proper utilization of the composites, adequate testing and evaluation programmes are essential. The paper briefly describes the development of WPC at the Bhabha Atomic Research Centre, Bombay, and the evaluation of WPC for various applications in greater details. The various mechanical properties and their significance in overall performance of WPC are also discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

A membrane process utilizing dialysis and selective complexation by water-soluble polymers has been developed. This process, termed affinity dialysis, has been shown to be selectively extract and concentrate both cations and anions in a manner similar to ion exchange or solvent extraction. The selective removal of calcium from sodium with selectivity of about 30, removal of chromate ion from dilute streams, and separation of transition metal ions such as Cu/Fe and Cu/Zn have all been successfully demonstrated. Effects of different polymers, polymer concentration, temperature, and flow rates have been studied. The effect of increased polymer concentration is to increase product concentration if appropriate changes in feed, polymer solution, and strip flow rates are made. A continuous polymer solution recycle and regeneration system has been constructed and ...

Energy Technology Data Exchange (ETDEWEB)

Nanoimprinting is a fast-growing technique for nanoscale patterning. One of the remaining issues in nanoimprinting is the removal of the residual layer after nanoimprinting. Traditionally the residual layer is removed by an oxygen reactive-ion etching (RIE) step. The need for a vacuum environment and dedicated equipment in this step lowers the throughput and increases the cost of the nanoimprinting process. It also prevents the possibility of patterning isolated functional polymers because oxygen RIE destroys the functional materials. In this work, novel nanoimprinting schemes are developed to nondestructively remove the residual layer in thermal nanoimprinting by solvent developing and dewetting. Combined with a transfer-bonding technique, three-dimensional polymer scaffolds are achieved. The techniques developed here eliminate the RIE step in thermal nanoimprinting and are compatible with roller nanoimprinting for large-scale patterning of ...

Energy Technology Data Exchange (ETDEWEB)

The adverse effect of moisture diffusion on the properties of wood has been one of the main weaknesses of wood. Using a gamma irradiation method, wood-polymer composites have been produced which exhibit significant improvement in mechanical properties like compression, creep deformation and creep rupture particularly at high humidity. It has been thought that the impregnation of polymer into the wood has affected the moisture diffusion in the wood, so that its adverse effects on the mechanical properties has been reduced. In this report the apparent diffusion coefficients of a Ramin wood impregnated with varying amounts of polymethyl methacrylate (PMMA) were determined using a Fick's law approach. An initial linear relationship was found for impregnation of up to 70% PMMA, after which the diffusion coefficient levels off to a maximum value, for the three environmental relative humidity levels of 40, 60 and 90({plus minus}5)%. The ...

Science.gov (United States)

The kinetics of electrical breakdown of thin (15-70 ?m) layers of polymers and ceramics in a constant-sign field at 77-480 K has been investigated. The temperature dependences of the longevity (breakdown waiting time) of both dielectrics have been found to be similar to each other. At elevated temperatures, the longevity of the dielectrics varies exponentially with increasing temperature, and at reduced temperatures, it is temperature-independent (there is an athermal plateau). The mechanisms of elementary events controlling the process of preparation of the dielectrics for breakdown at elevated and reduced temperatures are the thermal-fluctuation over-barrier electron transition from trap to trap and the tunneling (under-barrier) transition, respectively. The hopping electron transport in the field direction gives rise to critical space charges causing breakdown of the dielectrics. The transition barrier heights (trap depths) have been determined. The ...

Science.gov (United States)

We study the emission zone in a single-layer polymer light-emitting diode. The emission zone is found by studying the angular distribution of the electroluminescence. The emission is modeled by accounting for optical interference. We account for birefringence of the anode layer in our model. The active polymer was, however, found to be isotropic. The anode consists of a single-layer of the conducting polymer complex poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonate) (PEDOT-PSS), with enhanced conductivity. As a cathode we use plain aluminum. By using only PEDOT-PSS we avoid having a thin metal layer or indium-tin-oxide as the anode in the path of the escaping light. The active material is a substituted polythiophene with excellent film forming properties. A comparison between the experimental and calculated angular distribution of light emission from a single-layered polymer light-emitting ...

International Nuclear Information System (INIS)

Hybrid organic-inorganic coatings with phosphonate functionalities have been synthesized and evaluated as prospective surface treatments for magnesium materials. These coatings have been processed via a sol-gel route by hydrolysis and condensation of a mixture of diethylphosphonatoethyltriethoxy-silane and tetraethoxy-silane with variable molar ratios. The coatings morphology and the surface chemistry at the coating/substrate interface have been characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, "3"1P nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry. The corrosion protection performance of the coatings deposited on magnesium alloy AZ31B has been examined by a group of electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, a scanning Kelvin probe technique has been used to investigate interfacial properties of the coatings. ...

Energy Technology Data Exchange (ETDEWEB)

The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 deg. C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young's modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young's modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did ...

International Nuclear Information System (INIS)

The intensity of erbium up-conversion luminescence could be limited by a saturation effect due to increased pump power. We studied the luminescence saturation of the 550 nm emission on erbium-doped, SiO_2-TiO_2 sol-gel powders under pulsed excitation at 979 and 1532 nm. From the latter, the up-converted luminescence intensity decreased with increasing excitation power, whereas no saturation was observed at 979 nm excitation. We proposed that the saturation effect is determined by the pump power, the erbium content and the lifetime of the corresponding first excited states at different pumping schemes.

British Library Electronic Table of Contents (United Kingdom)

Silica-reinforced natural rubber (NR) composite was prepared by using tetraethoxysilane (TEOS) as a precursor to generate silica particles inside the rubber. The silica was generated in situ by the sol-gel process of TEOS that was mixed directly into commercial-graded NR latex having 60% dry rubber content and 0.7% ammonia. The conversions of TEOS to silica inside the rubber were ranging from 90 to 97%. The silica particles dispersed evenly without extensive aggregation with sizes between 100 and 500 nm, as determined by scanning electron microscopy (SEM). An experimental design methodology, namely "two-level factorial design," was used to evaluate the influence of the amounts of TEOS, ammonia, and gelation time on the tensile modulus, tensile strength, and tear strength of the vulcanizate...

International Nuclear Information System (INIS)

The separation and the mechanism of retention of ion associates of #alpha#-isomers of molybdic and tungstic heteropoly acids (HPA) of phosphorus(5), silicon(4), and germanium(4) with trioctylamine (TOA) on a column (80x3 mm) packed with Diasorb-130-CN (8 #mu#m) were studied in a flow of chloroform-tetrahydrofuran (THF) and chloroform-n-butanol-TOA mixtures with spectrophotometric detection at 320 nm. It is demonstrated that the adsorption of all the studied ion associates proceeds through the displacement THF molecule from the surface of the stationary phase and without the displacement of TOA molecules. Conditions for the separation of phospho- and silicomolybdic HPA and also phospho- and germanolybdic HPA were found. The chromatographic system using silica gel modified with nitrile groups as the stationary phase is of higher selective than that using ummodified silica gel.

British Library Electronic Table of Contents (United Kingdom)

We have investigated the effect of manganese (Mn) doping on properties of nanosized biphasic calcium phosphate powders and their dense bodies. Manganese levels of 0.6, 1.3, 1.9, 4.3, 7.0 and 11.9at.% were successfully incorporated into biphasic calcium phosphate via a sol-gel route. The prepared powders were calcined at temperatures of 500-1200^oC. The X-ray diffraction analysis revealed that a mix phase comprising of hydroxyapatite and @b-tricalcium phosphate were present, however the content of each phases in the structure was affected by the Mn content. The studies found that the largest portion of @b-tricalcium phosphate was detected at 4.3at.% Mn doping. The incorporation of Mn has also greatly increased the crystallinity of the biphasic calcium phosphate powder due to progressive den...

International Nuclear Information System (INIS)

In the present study the authors have shown that glycoproteins are present in the plasma membrane of Acanthamoeba castellanii by utilizing different radioactive labeling techniques. Plasma membrane proteins in the amoeba were iodinated by "1"2"5I-lactoperoxidase labeling and the solubilized radiolabeled glycoproteins were separated by lectin-Sepharose affinity chromatography followed by polyacrylamide gel electrophoresis. The periodate/NaB"3H_4 and galactose oxidase/NaB"3H_4 labeling techniques were used for labeling of surface carbohydrates in the amoeba. Several surface-labeled glycoproteins were observed in addition to a diffusely labeled region with M_r of 55,000-75,000 seen on electrophoresis, which could represent glycolipids. The presence of glycoproteins in the plasma membrane of Acanthamoeba castellanii was confirmed by metabolic labeling with ["3"5S]methionine followed by lectin-Sepharose affinity chromatography and polyacrylamide gel ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Gelatinization temperature (GT) is an important parameter in evaluating the cooking and eating quality of rice. Indeed, the phenotype, biochemistry and inheritance of GT have been widely studied in recent times. Previous map-based cloning revealed that GT was controlled by ALK gene, which encodes a putative soluble starch synthase II-3. Complementation vector and RNAi vector were constructed and transformed into Nipponbare mediated by Agrobacterium. Phenotypic and molecular analyses of transgenic lines provided direct evidence for ALK as a key gene for GT. Meanwhile, amylose content, gel consistency and pasting properties were also affected in transgenic lines. Two of four nonsynonymous single nucleotide polymorphisms in coding sequence of ALK were identified as essential for GT. ...

Energy Technology Data Exchange (ETDEWEB)

This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted ...

Science.gov (United States)

Before electroless plating, polymer surfaces must be sensitized and/or activated by using either the conventional two-step or one-step process. The latter stage is a compulsory one to make such surfaces catalytic, e.g., for Ni-P deposition. These processes are performed here using O{sub 2}, NH{sub 3}, or N{sub 2} plasma pretreatments. Reaction mechanisms are proposed for each of the processes and for each type of surface considered (oxygenated or both oxygenated and nitrogenated by the plasma treatment). Direct palladium chemisorption onto nitrogenated groups is highlighted. This allows one to simplify the process making the surface catalytic via elimination of the use of SnCl{sub 2} and to extend the method to any polymer. An additional interest of the plasma treatments, besides their high efficiency in grafting chemical functions, is to perform this grafting at will on selected areas which results in selective metallization.

British Library Electronic Table of Contents (United Kingdom)

Nanocapsules coated by medicinal plants have many applications in drug manufacturing. Medicinal plants can be loaded on nanocapsules with polyesteric triblock copolymer poly ethylene glycol-poly butylene adipate-poly ethylene glycol (PEG-PBA-PEG) as shell and olive oil can be introduced as a core of nanocapsules by a method known as polymer deposition solvent evaporation method. In this research, first, certain amount of polymer, Matricaria recutita extract and olive oil were mixed with acetone and then, water was added to the solution using magnetic stirrer. After which the acetone was removed by vacuuming and finally nanocapsules were found by freezing-drier. The study showed the size of nanocapsules depends on variety of factors such as the ratio of polymer to oil and concentration of p...

CERN Document Server

We discuss theoretically and numerically the intramolecular form factor $F(q)$ in dense polymer systems. Following Flory's ideality hypothesis, chains in the melt adopt Gaussian configurations and their form factor is supposed to be given by Debye's formula. At striking variance to this, we obtain noticeable (up to 20%) non-monotonic deviations which can be traced back to the incompressibility of dense polymer solutions beyond a local scale. The Kratky plot ($q^2F(q)$ {\\it vs.} wavevector $q$) does not exhibit the plateau expected for Gaussian chains in the intermediate $q$-range. One rather finds a significant decrease according to the correction $\\delta(F^{-1}(q)) = q^3/32\\rho$ that only depends on the concentration $\\rho$ of the solution, but neither on the persistence length or the interaction strength.

Science.gov (United States)

A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 membrane.

Energy Technology Data Exchange (ETDEWEB)

The performance of different polymers used to flocculate red mud particulate materials in the Bayer process can be evaluated on the basis of their efficiency to achieve adequate settling velocities and turbidity levels. In this study, three commercially available flocculants are evaluated under typical conditions found in the last washer of a Bayer plant. The different shear levels are produced by using a modified Couette flow system. Great differences are noticed in the performance of the polymers when they are compared at different dosages and at different shear rate levels. The data collected also suggests that conventional cylinder settling tests may not be adequate to measure the performance of certain types of polymers. (author)

International Nuclear Information System (INIS)

Some results and experimental procedures of laboratory are reported in the frame of researches conducted for the development of new nanostructured composite materials. These new materials, which are constituted by an organic phase: the polymer and an inorganic phase: the silicate, are being strongly investigated nowadays so it is expected that they could provide, among other, better electrical insulation properties and flame-delay in electrical and electronic applications. The laboratory experimental work has been developed from two families of polymers, thermoplastics and thermosets and clays silicates providing lamellar type. There are now some preliminary results, such as obtaining thin films of these nanocomposite materials, their complete characterization by X-ray diffraction, scanning microscopy and thermogravimetric analysis, they do well to wait for future research activities. (author)

Energy Technology Data Exchange (ETDEWEB)

New technologies are needed to reduce the current high rate of well abandonment. Improved sweep efficiency, reservoir conformance, and permeability modification can have a significant impact on oil recovery processes. Microorganisms can be used to selectively plug high-permeability zones to improve sweep efficiency and impart conformance control. Studies of a promising microbial system for polymer production were conducted to evaluate reservoir conditions in which this system would be effective. Factors which can affect microbial growth and polymer production include salinity, pH, temperature, divalent ions, presence of residual oil, and rock matrix. Flask tests and coreflooding experiments were conducted to optimize and evaluate the effectiveness of this system. Nuclear magnetic resonance imaging (NMRI) was used to visualize microbial polymer production in porous media. Changes in fluid distribution within the pore system ...

CERN Document Server

The emergence of nanoscience has increased the importance of experiments able to probe the very local structure of materials, especially for disordered and heterogeneous systems. This is technologically important; for example, the nanoscale structure of glassy polymers has a direct correlation with their macroscopic physical properties. We have discovered how a local, high frequency dynamic process can be used to monitor and even predict macroscopic behavior in glassy polymers. Polyvinylethylenes vitrified by different chemical and thermodynamic pathways exhibit different densities in the glassy state. We find that the rate and amplitude of a high frequency relaxation mode (the Johari-Goldstein process involving local motion of segments of the chain backbone) can either correlate or anti-correlate with the density. This implies that neither the unoccupied (free) volume nor the configurational entropy governs the local dynamics in any general ...

UK PubMed Central (United Kingdom)

The polysaccharide components from cultured cells of Rhizobium fredii USDA205 and Rhizobium meliloti AK631 were extracted with hot phenol-water and separated by repetitive gel filtration chromatography....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Synthetic zeolite of 0.5 nm pore size (5A) and blue silica gel were tested to determine their capability to be used as radon collectors. Tests conducted in a radon chamber under controlled conditions of temperature and relative humidity indicate that simple, inexpensive and maintenance-free passive devices containing about 250 g of synthetic zeolite or about 270 g of blue silica gel in open face metal canisters that can measure radon conveniently and adequately, the latter though being suitable only for dry-medium dry atmosphere with quite high radon concentrations. Both materials can be recycled for reuse, in a way similar to the recycle and reuse of active carbon. The amount of radon adsorbed in such collectors is determined by counting the gamma rays from the radon decay products. The lower limit of detection (LLD) is estimated to {approx}45 Bqm{sup -3} for the synthetic zeolite and to {approx}350 Bqm{sup -3} for the blue silica ...

International Nuclear Information System (INIS)

Three major monomeric hemoglobins have been isolated from the erythrocytes of Glycera dibranchiata. Their importance to structure-function studies of heme proteins lies in the fact that they have been shown to possess an exceptional amino acid substitution. In these proteins, the E-7 position is occupied by leucine rather than the more common distal histidine. This substitution alters the polarity of the heme ligand binding environment compared to myoglobin. Due to this, the G. dibranchiata monomer hemoglobins are attracting much attention. However, until now no purity criterion has been developed. Here the authors demonstrate that, for all of the Glycera momomer hemoglobins, multiple line patterns are shown on high-voltage isoelectric focusing (IEF) gels. Most of these lines are shown to be a consequence of heme-related phenomena and can be understood on the basis of changes in oxidation and ligation state of the heme iron. The multiple line pattern does not ...

UK PubMed Central (United Kingdom)

Amplification of oncogenes has been found to be an important prognostic factor in behavior of patients' malignancies. In this study we have used new gel electrophoresis techniques to follow the location...Full Text Available

International Nuclear Information System (INIS)

The complex formation of astatine(I) cation with diethylene triamine pentaacetic acid (DTPA) and characterization of the complexes were investigated by electromigration in free electrolytes and by gel-chromatography on Sephadex G 25. The conjugation procedure for the production of At-DTPA conjugated polyclonal antibodies is described. (author) 15 refs.; 2 figs.

UK PubMed Central (United Kingdom)

The heat resistance of spores of Bacillus subtilis formed at 30°C was enhanced by pretreatment at 48°C for 30 min, 60 min into sporulation, for all four strains examined....Full Text Available

UK PubMed Central (United Kingdom)

A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

The electric explosion of a conductor being part of an electric cable is studied. It is ascertained that the electric properties of a polymeric dielectric depend nonlinearly on the maintenance of the ultradisperse metal filler. In the course of the numerous heating-cooling processes of an insulator, a streamlining of the structure of a polymeric composite occurs.

Energy Technology Data Exchange (ETDEWEB)

Using a series of polycations synthesized by atom transfer radical polymerization (ATRP), we investigate the effects of the polymer charge density and hydrophobicity on salt-induced interdiffusion of polymer layers within polyelectrolyte multilayer (PEM) films. Polycations with two distinct hydrophobicities and various quaternization degrees (QPDMA and QPDEA) were derived from parent polymers of matched molecular weights poly(2-(dimethylamino)ethyl methacrylate) (PDMA) and poly(2-(diethylamino)ethyl methacrylate) (PDEA) by quaternization with either methyl or ethyl sulfate. Multilayers of these polycations with polystyrene sulfonate (PSS) were assembled in low-salt conditions, and annealed in NaCl solutions to induce layer intermixing. As revealed by neutron reflectometry (NR), polycations with lower charge density resulted in a faster decay of film structure with distance from the substrate. Interestingly, when comparing ...

Energy Technology Data Exchange (ETDEWEB)

Polymers are required to use in radiation environments as insulation materials. However, they often suffer from tracking failure. There is an increasing demand to evaluate radiation effects on dielectric performance. This paper presents a recurrence plot (RP) approach to analyse surface discharge sequences of gamma-ray irradiated polymer materials based on tracking test. Studying the non-linear characteristics of discharge sequences can assist in understanding the underlying mechanism of the discharge process. Discharge sequences of the test are extended to m-dimensional phase space by using the phase space reconstructed method. As test samples, polybutylene terephthalate (PBT) and polybutylene naphthalate (PBN) were irradiated to 100 kGy and then up to 1 MGy with a dosage rate of 10 kGy h{sup -1} by using a {sup 60}Co gamma source. The tracking tests were carried out according to the test method described in IEC60112. It is found that the RPs ...

UK PubMed Central (United Kingdom)

Dimethacrylate polymers and composites are seeing increased usage in orthopedics. As these applications require the material to integrate with the surrounding tissues, direct contact cytotoxicity...Full Text Available

Science.gov (United States)

... Highly-Functional Materials" was launched in JFY1996 under the New Materials field. This project was ... Bio-mimetic materials" (1) Advanced stimuli responsive materials (2) Harmonized molecular materials ...

UK PubMed Central (United Kingdom)

Synthetic polypeptide antigens of L amino acids, although bearing repeating sequences, are thymus-dependent (L-TD), whereas the same polymers composed of D amino acids are thymus-independent (D-TI),...Full Text Available

International Nuclear Information System (INIS)

In the synthesis of the peptidyl-polymer corresponding to the sequence (57-100) of the #beta# chain of human hemoglobin on Teflon with radiationally grafted polystyrene a comparative study was made of different methods of fragment condensation. It was shown that the most effective methods are azide condensation and condensation with the use of complex F.

Science.gov (United States)

Measurements of PEM fuel cell device performance were made with different gas inlet temperatures and relative humidity using a newly-designed test fixture. Significant improvement in device performance was observed when the fuel inlet temperature was increased above the operating temperature of the cell. These measurements were then correlated to a model to describe energy and mass transport processes. Proton exchange membrane (PEM), fuel cells--the focus of this study--use an ion conducting polymer, especially polyperfluorosulfonic acid materials. These polymer materials, when imbibed with water, exhibit solution-like properties, but because the anions are chemically bound to the polymeric structure, the electrolyte is contained. Importantly, product water removal is simplified, as electrolyte dilution is not a concern. However, the proton transport rate is a function of the polymer geometry, which is set, in part, by the ...

Science.gov (United States)

... of new construction materials; and the behavior of infrastructure materials and structural ... polymers, reinforcing materials, wood and biodegradable structural materials; scale effects from ...

Science.gov (United States)

international vehicles, control centers, and ground support personnel. ... consists of thin membranes made from a polymer-based film and ..... (including airplanes and submarines), environmental monitoring, and control ...... sciences can use it to analyze the birth and death of stars, the formation of solar ...

International Nuclear Information System (INIS)

This is a preliminary study on the sound absorption properties of two tropical hardwoods, Light Red Meranti and Ramin, and their wood-polymer composites. Sound absorption is measured using a standing wave apparatus. The samples are of one thickness (7 mm) and cut longitudinally. Wood-polymer composites are made by impregnating the samples with methyl methacrylate which is polymerized in situ through #gamma#-irradiation. Both woods and their composites are better sound absorbers at higher sound frequencies. With partial impregnation, the absorption coefficients are improved upon particularly in the region between 1-3 kHz. (author).

Energy Technology Data Exchange (ETDEWEB)

The resistance of six tropical hardwoods to fungal degradation by two wild-type strains of Phanerochaete chrysosporium Burdsall was investigated using vermiculite burial and wood-block weight loss techniques. Radiation-induced wood-polymer composites (WPC), based on two hardwoods Ramin and Rubberwood with methyl methacrylate, were prepared, and samples were also exposed to the wood-rotting fungus. A significant improvement in resistance to fungal decay was observed in the WPC. Scanning-electron micrographs of the two woods and their composites after fungal degradation are presented and discussed.

International Nuclear Information System (INIS)

Radiation-initiated polymerization of styrene and acrylic acid in poplar wood were investigated for the preparation of wood-polymer composites. The direct irradiation method was applied to the monomer adsorbed poplar wood specimens. 8000 Ci "6"0Co source at a dose rate of about 0.4 Mrad/h was used. Furthermore the effects of carbon tetrachloride, methanol, dioxane and acrylonitrile on styrene polymerization were investigated and the reaction rates were calculated for each case. The influence of CCl_4 (10%) on acrylic acid polymerization in poplar wood was also determined. (author).

Science.gov (United States)

The removal of Reactive Black 5 dye in an aqueous solution by electrocoagulation (EC) as well as addition of flocculant was investigated. The effect of operational parameters, i.e. current density, treatment time, solution conductivity and polymer dosage, was investigated. Two models, namely the artificial neural network (ANN) and the response surface method (RSM), were used to model the effect of independent variables on percentage of dye removal. The findings of this work showed that current density, treatment time and dosage of polymer had the most significant effect on percentage of dye removal (p0.8). PMID:21411950

British Library Electronic Table of Contents (United Kingdom)

Purpose - This paper aims to describe the technology and applications of nanocomposite materials. Design/methodology/approach - This paper discusses products, applications and technological developments in polymer, ceramic and metal nanocomposites. It concludes with a brief consideration of electronic component applications. Findings - It is shown that polymer nanocomposites and the materials used in their production are commercially available and finding applications in several industries, including automotive, military, food, electronics and leisure, due to their enhanced mechanical, electrical and thermal properties. Ceramic and metallic nanocomposites are at an earlier stage of development and a critical issue to resolve is optimising the dispersion of nanomaterials in the matrices. Pa...

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This paper describes the experimental results of accelerated aging tests conducted on three different types of polymer materials. Salt fog chamber tests were used to study the surface degradation modes for all materials. The work presented here was performed using a newly constructed fog chamber system that was able to control both chamber humidity and UV radiation. The changes in the surface morphology, material structure and leakage current were examined to study the influence of environmental humidity.

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Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a {sup 60}Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used.

International Nuclear Information System (INIS)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a "6"0Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used. (author)

International Nuclear Information System (INIS)

Polymer composites are used in numerous applications. In spite of this fact, new developments are still under way to explore in other field of application of these materials and to tailor their properties for more extreme condition. A particular emphasis is focused on fillers content is summarized. Some steps towards the functionally graded materials are illustrated. The FT-IR spectroscopic studies revealed the information about curing of epoxy with fillers. It was observed that mechanical properties like tensile strength, hardness etc get enhanced up with filler contents. The effect of the different formulations were investigated and discussed for optimum process condition. (author)

Energy Technology Data Exchange (ETDEWEB)

The currently available propellants achieve about 95% of the combustion performance which can be expected theoretically at this time, consequently a technological breakthrough concerning new propellants have been demanded. Among high energy substances which are being studied, polymer azide which can continue combustion without relying on the oxidation reaction is a typical high energy substance to be used for a propellant of the next generation. The composite propellant which has polymer azide as fuel component and ammonium nitrate as oxidizer is considered to be the extremely promising propellant, since it provides no combution product which causes the environmental destruction. (6 figs, 4 refs)

Energy Technology Data Exchange (ETDEWEB)

An apparatus was designed and built for the purpose of exposing samples of solid polymers to varying temperatures, atmospheres and stress levels while quantitatively recording the resulting chemiluminescence. Preliminary data were acquired with this apparatus that show a correlation between an enhanced chemiluminescence signal at a low level of applied stress and a decrease in tensile strength for the most commonly used epoxy resin in high performance fiber composites, TGMDA DDS. The studies with cellular silicone cushions (which are used to accommodate thermal expansion and contraction) have defined the temperature regimes in which accelerated aging tests are valid for extrapolation to ambient temperature. Preliminary data on Kevlar fibers is also discussed.

Energy Technology Data Exchange (ETDEWEB)

Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, ...

International Nuclear Information System (INIS)

Thermoplastic polymer materials and the compounds made with them are being used more frequently for industrial components and for general use. However, the application of these materials for the production of complex shaped or relatively large pieces is limited, because of the difficulty and cost of making the necessary tool kit for the job. One solution is the use of the welding process. But the safe and reliable union of different thermoplastic material parts is not a simple process, even less so in the case of unions of large components. Welding by microwaves using polymer conductors can help, since the large scale equipment is available, and methods for continuous processes by microwave have been developed, that can be used to weld large and small components. Many thermoplastics (ex. polyethylene) do not absorb, or absorb very little, energy from microwaves. Polymer conductors, however, heavily absorb from microwaves ...

British Library Electronic Table of Contents (United Kingdom)

To improve the photocatalytic application performances of TiO2, in this work, firstly CdS modified Degussa P25 TiO2 (CdS/TiO2) composites were prepared by two methods, sol-gel method and precipitation method. Next they, sol-gel-CdS/TiO2 (sg-CdS/TiO2) and precipitation-CdS/TiO2 (pp-CdS/TiO2), were loaded on activated carbon fibers (ACFs) by dip-coating method using the sodium carboxymethyl cellulose as adhesives. The composites were characterized by XRD, UV-vis absorbance spectra, SEM, EDS and BET. The photocatalytic activities under sunlight were investigated by the degradation of methylene blue. The results showed that CdS/TiO2 composites were mainly composed of anatase-TiO2 and little CdS cubic phases. The absorption wavelengths of sg-CdS/TiO2 and pp-CdS/TiO2 composites were extended to ...

British Library Electronic Table of Contents (United Kingdom)

Objective: The aim of this study was to compare symptoms and anterior segment tolerability with short-term (3-day) administration of once-daily timolol hemihydrate 0.5%, timolol maleate in sorbate 0.5%, and generic timolol maleate gel-forming solution 0.5% in the treatment of glaucoma and/or ocular hypertension. Methods: In this prospective, randomized, double-masked, active-controlled, 3-period crossover pilot study, eligible patients had primary open-angle, pigmentdispersion, or exfoliation glaucoma, and/or ocular hypertension in >=1 eye; had a best corrected visual acuity of 1.0 or better in each eye, as measured using the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity testing chart; were receiving 1 glaucoma medication; and had an untreated intraocular pressure (IOP) ...

British Library Electronic Table of Contents (United Kingdom)

The nanostructure Ni-doped CdO films have been prepared by sol gel spin coating method. Atomic force microscopy results indicate that the CdO films are formed from the nanoparticles and the grain size is changed with nickel content. X-ray diffraction patterns of the films indicate that the undoped and Ni-doped CdO films have polycrystalline structure with a cubic sodium chloride structure, showing two main characteristic peaks assigned to the (111) and (200) planes. The optical band gap values of undoped and Ni-doped CdO films were determined by optical absorption method. The Eg values of the CdO films were found to be in the range of 2.26?2.60?eV. The Eg values of the CdO films increase with the content of Ni dopant (up to 6% Ni). It is evaluated that the optical band gap and grain size o...

Energy Technology Data Exchange (ETDEWEB)

Mullite long fibres, which are a candidate for high temperature applications were prepared by sol-gel method from water solvent systems. They were synthesized from three different combinations of raw materials as follows: (1):Al(O{sub 1}C{sub 3}H{sub 7}){sub 3}, Al-nitrate and Si(OC{sub 2}H{sub 5}){sub 4} (TEOS), (2):Al metal, Al-chloride and TEOS, (3):Al metal, Al-nitrate and TEOS. In the methods (1) and (2), very fine SiO{sub 2} aerosol particles were also used partially replacing TEOS. The prepared solutions were condensed and examined the spinability by a hand drawing method. Dense and crack free mullite fibres were prepared from the methods (1) and (3) by firing up to 1100 C. Whereas the fibres prepared from the method (2) were less SiO{sub 2} than mullite composition and were porous by the firing due to evaporation of residual Cl ions at high temperature. (orig.) 10 refs.

Science.gov (United States)

Enthalpy relaxation properties of the ethylene glycol (EG) aqueous solutions confined within silica-gel void spaces of 1.1 nm in the average void thickness and 6, 12 and 52 nm in their average diameters were examined by an adiabatic calorimetry to understand the glass transition behavior of the solutions and the rearrangement processes of the molecules. The glass transition temperature Tg of EG was found to decrease with adding the water molecules which are mobile under the condition lacking in the full hydrogen-bond network. Meanwhile, the Tg in the water-rich region showed a rise towards pure water; after a phase separation in a 25 mol% (x = 0.25) EG solution, the Tg was 160 K which was higher than that derived by extrapolating the composition dependence to pure water. The Tg = 160 K is the same as observed in the pure water confined within 1.1 nm voids; this indicates the validity of the interpretation that the glass transition at 160 K of the confined water ...

International Nuclear Information System (INIS)

The nanosized luminescent Tb-MCM-41 (1:10) is synthesized by means of sol-gel-assisted self-assembly under basic conditions at room temperature. The results of "2"9Si-MAS NMR and XRD prove that Tb"3"+ doped Si-O framework. The HRTEM image shows that the regular uniform particles with a diameter of 10 nm possess ultralarge pore with diameter 2.0 nm, which is consistent with the result of N_2 adsorption. The BET surface area and porosity of Tb-MCM-41 (1:10) are 1127 m"2/g and 0.84 cm"3/g, respectively. The patterns of selected-area electron diffraction and XRD of Tb-MCM-41 (1:10) show an Fm3m space group in the cubic. FT-IR results show that the peaks near 970 cm"-"1 are assigned to the deformation vibration of silanol group. The as-products are calcined at 800 deg. C and the mesoporous materials possess enormous specific areas and large porosity, it shows that the mesoporous materials are ultrastable.

Energy Technology Data Exchange (ETDEWEB)

The aim of this study was to search for a sorbent that could act as an extraction phase and as a support for solid-matrix time-resolved luminescence (SMTRL). Four potential sorbents were investigated for this purpose using tetracycline (TC) as a model analyte. Sorbents prepared from C18 silica gel or calcium cross-linked pectin gel were able to extract TC from dilute solutions. Europium(III)-TC complex adsorbed on the surface of C18 generated the most intense TRL signal when measured at {lambda}{sub ex} = 388 nm and {lambda}{sub em} = 615 nm. This method achieved a 1 ng/ml limit of detection (LOD) with a 100 {mu}l sample solution in a repeated spotting mode. Hyphenation of sorbent extraction and SMTRL was demonstrated using C18. This method is suitable for screening of TC in foods or aqueous solutions and can be extended to other luminescent lanthanide-chelating analytes in physiological or environmental samples.

International Nuclear Information System (INIS)

The following are reported: colorimetric determination of Ti in Cr, decontamination of metals by anodic dissolution, computer code for x-ray peak identification, gel-permeation chromatography of CoRezyn 1664 polyester resin, infrared monitoring of gases and vapors, particle size analysis of dusts, nondestructive analysis of Oralloy for removable alpha contamination, dissolution (digestion) of high-fired oxides, assay of U in a Pu-U alloy, measurement of oxide thickness on Pu metal by x-ray diffraction, analysis of precipitated Pu peroxide, differentiation of Dowex SBR and 11 resins, and determination of Pu solubility in simulated lung fluid.

British Library Electronic Table of Contents (United Kingdom)

Palladium silicide was formed on the sol-gel derived SiO2 supported Pd catalysts prepared by ion-exchange method (Pd/SiO2-SG-ion). However, the catalysts exhibited superior performances than commercial SiO2 supported ones in liquid-phase semihydrogenation of phenylacetylene. It was probably due to an inhibition of a product of styrene, which is adsorbed on the surface of Pd, more strongly on Pd/SiO2-SG in which Pd is electron-deficient as shown by larger binding energy from XPS results.

Energy Technology Data Exchange (ETDEWEB)

The effects of temperature and the use of macroreticular resins were studied in lithium isotope separation by an ion-exchange method. The isotope separation factors obtained decreased by increasing the temperature, and the factors for macroreticular resins were identical with those for the usual gel-type resins. However, the performance of isotope separation per unit band length in displacement chromatography was found to be improved by increasing the temperature and using macroreticular resins, because accelerating the interphase mass transfer caused the reduction of HETP (Height Equivalent to a Theoretical Plate).

International Nuclear Information System (INIS)

The radiation degradation behavior of three commercial polyvinyl chloride (PVC) materials has been investigated. All three exhibit an interesting reversal in the trend of the tensile strength part way through the aging experiment: the tensile strength first drops, then rises. The early drop is associated with oxidative scission; the rise is associated with crosslinking and is preceded by the material reaching the gel point. It was also found that the tensile elongation tended to level out in advanced stages of aging with the levelling-out values dependent on the dose rate. These phenomena pose complications for the design of accelerated aging tests. (author).

Science.gov (United States)

IntroductionBreast cancer is the most diagnosed and second leading cause of cancer deaths in the U.S. female population. An estimated 5 to 10 percent of all breast cancers are inherited, caused by mutations in the breast cancer susceptibility genes (BRCA1/2). As many as 90% of all mutations are nonsense mutations, causing a truncated polypeptide product. A popular and low cost method of mutation detection has been the protein truncation test (PTT), where target regions of BRCA1/2 are PCR amplified, transcribed/translated in a cell-free protein synthesis system and analyzed for truncated polypeptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography. We previously reported a novel High Throughput Solid-Phase PTT (HTS-PTT) based on an enzyme-linked immunosorbent assay (ELISA) format that eliminates the need for radioactivity, SDS-PAGE and subjective interpretation of the results. Here, we report the next generation HTS-PTT ...

International Nuclear Information System (INIS)

Al, Ga and In complexing with methylthymol blue (H_6R) purified by gel filtration is studied. in the case of metal excess complexes with the ratio of components M:H_6R=2:1 with #lambda#=587(Al), 590(Ga) and 593 nm(In) appear. In the case of reacting agent excess complexes with the ratio of component 1:1 with #lambda#_m_a_x=480-490 (Al) and 480 nm(Ga, In) appear. The mechanism of complexing reactions is studied. Molar extinction coefficients and stability constants are calculated.

Energy Technology Data Exchange (ETDEWEB)

The chemical fixation of tritium in stearic acid followed by embedding the tritiated stearic acid into an epoxy resin proved to be a good method for permanent waste disposal of tritium gas. Tc-126 and Tc-136 hardener were used for this purpose. The polymerization temperature of the polymer products was found to be highly decreased by adding stearic acid and slightly decreased by adding stearic acid or by raising the temperature of the leachant medium and slightly decreased by irradiation. On the other hand, small improvement in the compressive strength of the polymer products was achieved by adding silica powder. The polymer product showed high flame points above 573 K although it contains stearic acid. DTA and TG analysis indicate that the thermal stability of polymer products containing stearic acid and silica powder is better than samples containing only stearic acid. Stearic acid was found to ...

Energy Technology Data Exchange (ETDEWEB)

The sol-gel-immobilized Tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy){sub 3} {sup 2+}] electrogenerated chemiluminescence (ECL) sensor was applied to the reversed-phase high-performance liquid chromatography (HPLC) determination of phenothiazine derivatives (promazine, chlorpromazine, triflupromazine, thioridazine, and trifluoperazine) and erythromycin in human urine samples. In this method, Ru(bpy){sub 3} {sup 2+} was immobilized in sol-gel-derived titania (TiO{sub 2})-Nafion nanocomposite films coated on a dual platinum electrode. This method eliminates an extra pump needed for the delivery of Ru(bpy){sub 3} {sup 2+} reagent into a reaction/observation zone in front of photomultiplier tube because the immobilized-Ru(bpy){sub 3} {sup 2+} is recycled on the electrode surface by an applied potential at +1.3 V versus Ag/AgCl (3 M NaCl) reference electrode. The resulting analytical performances such as detection limit, working range, ...

International Nuclear Information System (INIS)

Buffer layers with 100% lattice match with YBa2Cu3O7 - ? (YBCO) were prepared from mixed rare-earth-oxides applying a simple sol-gel process and dip-coating method. Structural analysis of the sol-gel derived powder by X-ray diffraction revealed that the mixing parameter, which eliminates the lattice mismatch with YBCO, is x = 0.2382, 0.1852, 0.1252, 0.0906, 0.0793 and 0.0395 in (Eu1 - xHox)2O3, (Eu1 - xErx)2O3, (Eu1 - xYbx)2O3, (Gd1 - xHox)2O3, (Gd1 - xYx)2O3 and (Gd1 - xYbx)2O3, respectively. Microstructural investigations were carried out for Gd1.819Ho0.181O3 films epitaxially grown on cube-textured Ni (100) substrates by sol-gel dip-coating process. X-ray diffraction of the buffer showed strong out-of-plane orientation on Ni tape. The (Gd1 - xHox)2O3 (222) pole figure indicated a single cube-on-cube textured structure. The omega and phi scans revealed good out-of-plane and in-plane alne alignments. The full-width at ...

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ZnMT has been postulated to function in essential metal homeostasis and metal detoxication. This study was undertaken to evaluate the potential of liver ZnMT to mediate the interaction of Zn and Pb with the Zn metalloenzyme, ALAD. Pretreatment of rats with Zn activated liver ALAD and attenuated the inhibition of ALAD by Pb in vitro and in vivo. Liver cytosol from Zn-pretreated rats injected with /sup 203/Pb was fractionated via gel filtration and anion-exchange chromatography and disclosed that both Zn and /sup 203/Pb co-eluted in the MT fractions. Both purified ZnMT-I and ZnMT-II bound /sup 203/Pb in vitro as shown by gel filtration chromatography. Addition of purified liver ZnMT to purified bovine liver ALAD reaction mixtures increased enzyme activity by 2-fold and prevented inhibition of ALAD by Pb. Addition of apothionein alone decreased the activity of Zn-activated ALAD and also attenuated Pb inhibition of the enzyme. ...

Energy Technology Data Exchange (ETDEWEB)

Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials ...

Energy Technology Data Exchange (ETDEWEB)

Poly(methyl methacrylate), PMMA, Acrigel, a Brazilian polymer, is used in the manufacture of medical supplies sterelizable by ionizing radiation. However, when PMMA is gamma-irradiated it undergoes main chain scissions, which promote molecular degradation causing reduction in its mechanical properties. Therefore, radiolytic of PMMA is important for it to become commercially radiosterizable. In this work some commercial additives, originally used in photo-and thermo-oxidate stabilization of polymers, were tested. Only two additives, type HALS (Hindered Amine Light Stabilizer), denoted Scavenger, showed a good protective quality. The investigation of radiation-induced main scissions was carried out by viscosimetric method. The most effective additive, added to the polymer system at 0.3 w/w%, promotes a great molecular radioprotection of 93%. That means a reduction of G-value (scissions/100 eV) from 0.611 to 0.053. In ...

Energy Technology Data Exchange (ETDEWEB)

The ink jet printing technology is a relatively novel technique in development of organic electronic devices. The technique consists of working out depositions of organic layers by a piezo-based ink jet printer. In this work polymer conducting films deposited by ink jet printing technique on different plastic substrates has been demonstrated. The poly(3,4-ethylenedioxythiofene)/poly(4-styrenesulfonate) [PEDOT/PSS] and glycerol-modified PEDOT/PSS [G-PEDOT/PSS] were used like conducting inks to be applied on polyester and polyethylene terephthalate (PET) substrates. By means of the change of substrate associated to the deposition number or type of polymer ink used for printing of the conducting films, the sheet resistance can be modified. Such a behavior suggests that plastic substrate fulfills an important role for the changing of sheet resistance of the PEDOT/PSS and G-PEDOT/PSS films made by ink jet printing technique. Films obtained from this ...

Energy Technology Data Exchange (ETDEWEB)

Samples of ultra-high molecular weight polyethylene (UHMWPE) and nylon 66, of grades suitable for use in medical prostheses, were subjected to irradiation using a /sup 60/Co source. The effects of a 10 Mrad dose on percentage crystallinity, tensile behaviour and dynamic mechanical response were established 3 days after irradiation at intervals over a one year period. Crystallinity in UHMWPE was found to increase progressively during this period with consequent changes in mechanical behaviour. It is proposed that the observed ageing process arises from the breakdown of metastable groups in the polymer, which are formed on irradiation, with consequent release of long inter-lamella tie chains. This removes an inhibition to crystal perfection processes, which can occur at room temperature in polyethylene. Infra-red spectroscopic evidence supports the proposal that the metastable species is peroxy or hydroperoxy and that this decomposes on ageing to a carbonyl group, ...

Environmental Research Database

Objectives1. To develop new photoactive materials and fabricate demonstration QD (quantum dot) solar cells. This will be achieved by:~%~1.1. Materials preparation and characterisation of QD/polymer systems~%~1.2. Optimising structures of QDs, nanorods and polymer for quantum yield and charge transfer~%~1.3 Fabricating demonstration QD/polymer solar cells and measuring power conversion efficiencies~%~2. To demonstrate multiexciton generation (MEG) and harvesting within nanostructured QDs. This will involv [continued...]DescriptionWidespread implementation of photovoltaic electricity to meet changing energy demands requires a step-change in the cost of photovoltaic power. This proposal assembles a consortium of chemists, physicists, materials scientists and electrical engineers from The University of Manchester and Imperial College London to address this need through the development of new low-cost, high-efficiency, ...

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The confocal Raman micro-spectroscopy has been used for the study of a Lithium/polymer electrolyte-LiTFSI/V{sub 2}O{sub 5} type battery in which the polymer electrolyte thickness is of about 80 {mu}m. The analysis is performed on the side of the battery thanks to a specially designed cell which preserves all the characteristics of the real system. The analysis is performed on 20 points aligned between the anode and the cathode and with a depth of several tenth of {mu}m. The analysis of data obtained during charging/output cycles allows to evaluate the gradients of salt concentration inside the electrolyte, the pollutions of LiOH, Li{sub 2}CO{sub 3}, Li{sub 2}O and Li{sub 3}N -type at the lithium interface, but also the structural modifications of the cathode material. The in-situ study of concentration gradients inside the electrolyte is of prime importance for the understanding of dendrites growth. (J.S.) 11 refs.

CERN Document Server

We show the existence of global-in-time weak solutions to a general class of coupled FENE-type bead-spring chain models that arise from the kinetic theory of dilute solutions of polymeric liquids with noninteracting polymer chains. The class of models involves the unsteady incompressible Navier-Stokes equations in a bounded domain in two or three space dimensions for the velocity and the pressure of the fluid, with an elastic extra-stress tensor appearing on the right-hand side in the momentum equation. The extra-stress tensor stems from the random movement of the polymer chains and is defined by the Kramers expression through the associated probability density function that satisfies a Fokker-Planck-type parabolic equation, a crucial feature of which is the presence of a center-of-mass diffusion term. We require no structural assumptions on the drag term in the Fokker-Planck equation; in particular, the drag term need not be corotational. With ...

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Different experimental measurements (Theology, granulometry, XRD) were carried out in order to study the main properties of bentonite suspensions in presence of anionic additives at different concentrations. These additives are: Sodium Dodecyl Sulfate (SDS) as surfactant, a flexible polymer (Sodium Carboxy Methyl Cellulose, CMC) and a semi-rigid polymer (Xanthan gum). It has been shown that the structural nature of anionic additive influences directly the mixtures viscoelastic and flow behavior. The steric effect of the surfactant modifies the Face-Edge interactions and yields changes of the mixtures rheological behavior at low deformation rates. Polymers act by coating each clay particle and prevent their agglomeration. Therefore, bentonite has no direct effect on the rheological behavior of the mixtures: the additives are responsible for the mechanisms of de-structuration and structure reorganization as well as the ...

Energy Technology Data Exchange (ETDEWEB)

Theoretical and experimental studies have been carried out on the combustion of azide polymers used as a binder in high-energy propellants. AMMO (3-azidemethyl-3`-methyloxetane) is one of the energetic azide polymers which contain N3 groups in their molecular structures. EDNA (ethylenedinitramine) is a linear nitramine which has modest properties in the flame temperature and the molecular weight of burned gases as compared with HMX (cyclotetramethylenetetranitramine) and NQ (nitroguanidine). In this study, the burning rate characteristics of azide/nitramine propellants were investigated in order to gain a wide spectrum of burning rate. As a result, the burning rate of AMMO/EDNA propellant is higher than that of AMMO/HMX propellant and the pressure exponent of AMMO/EDNA propellant is lower than that of AMMO/HMX propellant. Both AMMO/EDNA and AMMO/HMX propellants exhibited the same combustion wave structure as inert ...

International Nuclear Information System (INIS)

Comprehensive investigation has been made into the application of the polymerization hardening by radiation, particularly electron beam, to the composites of polymers and other materials. The report is divided into four parts, namely 1) characteristics and problems of the reaction of curing by radiation polymerization, 2) improvement of the bonding capability of high molecular weight materials, 3) bonding by radiation, and 4) composites made by the impregnation and polymerization hardening of monomers. The first part includes the effects of dose rate, temperature rise during the hardening, the peculiarity of electron beam irradiation at high dose rate, reaction environment and additive effects. Main conclusions are as follows: caution must be taken to the amount of residual double bonds because they affect the quality of hardened polymers; the polymerization hardening reaction at high dose rate cannot be analogized by that at low dose rate; and ...

Energy Technology Data Exchange (ETDEWEB)

The physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution. This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low razing incidence to centimeters for transmission ...

British Library Electronic Table of Contents (United Kingdom)

We propose and demonstrate a facile room-temperature synthetic method for obtaining water-soluble magnetic Fe3O4 nanoparticles (NPs) by combining the in situ synthesis and decomposition of a magnetic polymer hydrogel. The Fe3O4 NPs with average diameters of 6.3-8.3nm were synthesized in a cross-linked polyacrylamide (PAAm) hydrogel by coprecipitating iron ions. The decomposition of the magnetic polymer hydrogel by an aqueous solution of sodium hydroxide led to the transfer of Fe3O4 NPs into the aqueous medium. The NPs can be dispersed stably in water for more than three months. The Fe3O4 NPs were characterized by X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). The saturation magn...

Energy Technology Data Exchange (ETDEWEB)

In this program, contemporary solidification agents are being investigated relative to their applications to major fuel cycle and non-fuel cycle low-level waste (LLW) streams. Work is being conducted to determine the range of conditions under which these solidification agents can be applied to specific LLW streams. These studies are directed primarily towards defining operating parameters for both improved solidification of problem wastes and solidification of new LLW streams generated from advanced volume reduction technologies. Work is being conducted to measure relevant waste form properties. These data will be compiled and evaluated to demonstrate compliance with waste form performance and shallow land burial acceptance criteria and transportation requirements (both as they exist and as they are modified with time). 6 tables.

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Polymer insulating materials used in radioactive environments are subjected to a risk of surface degradation caused by tracking. The tracking behavior becomes more complex with the presence of magnetic field. This paper presents investigation of tracking failure of gamma-ray irradiated polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) under magnetic field. The samples were irradiated in air up to 100 kGy and then up to 1000 kGy with dose rate of 10 kGy/h by using a 60Co gamma-source. Magnetic field Formula Not Shown with flux density of 250 mT was assembled perpendicularly to electric field Formula Not Shown , which gave rise to relative angle between Formula Not Shown and surface normal vector Formula Not Shown of 0degree, 90degree and 180degree, respectively. The experi...

International Nuclear Information System (INIS)

In the Peruvian natural forest there are several kind of woods, some of those are not of commercial interest, because have not resistance at termites and wet, are too soft, or can not be well finished, in the others. The present work is devoted to improvement of the physical properties of wood, such as hardness, traction, wet resistance, etc., by means of the generation of a composite wood-polymers cured by using gamma irradiation. The main objective is to establish the main parameters for the polymerization process (economic technical aspect) that decrease the amount of water absorption, in consequence the volumetric variation of Catahua, Mohena and Capirona woods. Gamma irradiation also provides good protection against the biological agents. In consequence, these woods increase its intrinsic and economic values. (author)

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This paper deals with the preparation and characterization of polyaniline/TiO{sub 2} composite by XRD, UV-VIS spectra, TGA/DTA and FTIR. The composite is used as a cathode material for rechargeable battery comprising of zinc container as the anode, cellulose acetate as the separator and polyvinyl sulfate and carboxy methyl cellulose as the solid polymer electrolytes (SPE). By using the PAn/TiO{sub 2} composite as the cathode material, the cylindrical AA type rechargeable battery was fabricated and the following output was observed. The open circuit voltage (OCV) is 1.4 V and current is 250 mA to 1.0 A, 50 recharge cycles, power density is 350 A h/kg and power efficiency is 70%.

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The use of POE solid polymer electrolytes in negative lithium electrode batteries allows to reach energy density values close to 150 Wh/kg. The functioning of Li/POE/V{sub 2}O{sub 5} elements has been studied on small capacity elementary cells (about 26 mAh) and the results obtained were confirmed using coiled elements of 1.4 to 1.8 Ah capacity. This work has been carried out for Bollore Technologies (BT) and Electricite de France (EdF) companies. (J.S.)

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An effective rehabilitation strategy is proposed to enhance the strength and stiffness of the beam-column joint in this study. An analytical model is proposed to predict the column shear of the joints strengthened with carbon fiber reinforced polymer (CFRP). Three full scale interior beam-column joints, including two specimens strengthened with CFRP and one prototype specimen, are tested in this study. The specimens are designed to represent the pre-seismic code design construction in which there is no transverse reinforcement. A new optical non-contact technique, digital image correlation (DIC), which can measure the full strain field of specimen, is used to measure and observe the full strain field of the joint. The experimental results show that the beam-column joints strengthened with ...

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Abstract A one step method was used to prepare stable aqueous nanocomposite dispersions based on cellulose whiskers extracted from the rachis of the date palm tree and a poly(styrene co 2 ethyl hexylacrylate) copolymer via miniemulsion polymerization. A reactive silane, i.e., methacryloxypropyl triethoxysilane was added to stabilize the dispersion and favor the anchoring of the whiskers on polymer particles. Dynamic light scattering was used to study the effect of the silane and whiskers contents on the average particle size of the polymer. Nanocomposites materials were prepared from these dispersions using a casting/evaporation method. The effect of the silane and whiskers contents on the thermal and mechanical properties were studied using differential scanning calorimetry and dynamic me...

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This work deals with a new route to modify polymer blend morphology in order to improve the porosity of gas diffusion layers (GDLs) for proton exchange membrane fuel cells (PEMFCs). First, electrically conductive polymer-based blends were carefully formulated using a twin-screw extrusion process. Blend electrical conductivity was ensured by the addition of high specific surface area carbon black and synthetic graphite flakes. Final GDL porosity, in particular its macroporosity, was generated by melt blending polyamide 11 (PA11) matrix with polystyrene (PS) followed by PS extraction with tetrahydrofuran (THF) solvent at room temperature. In order to improve GDL porosity by the optimisation of PS dispersion in the PA11 matrix, PA11/PS blends were compatibilised by the addition of 2 wt.-% of ...

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This document reproduces the final project of David San Fabian Ayuso, presented on May 26, 2005, for the obtention of the engineer degree of the Carlos III University of Madrid. A single-phase, isothermal model, including both electron and proton transport, is introduced for the simulation of polymer electrolyte fuel cells (PEM). The model is implemented in the commercial code Fluent 6.0, through the use of UDFs (User Defined Functions). In order to validate the model, a single canal of a PEM monocell is simulated in three dimensions. The obtained result are qualitatively satisfactory. It is observed that it is not essential to solve the current collectors when a monocell is considered (and not a stack). in the present study, the number of nodes is the computational grid appears to be too low in the membrane zone in order to make a complete validation of the model. (Author) 20 refs.

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In Polymer Electrolyte Fuel Cell (PEFC) technology the reducing of volume and mass of the fuel cell stack and the improvement of catalyst utilization are of great interest. These parameters affect applicability and system cost. In this work we present an alternative way for reducing the stack volume by combining gas distribution and catalytic active area in one plate. Micro machined glassy carbon electrodes serve as support material for the platinum catalyst, as well as gas distributor at the same time. A comparison of these electrodes with conventional platinum-black gas diffusion electrodes under fuel cell conditions shows that the new system is a promising electrode type for enhanced power density and catalyst utilization. (author) 3 figs., 5 refs.

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Single stage separation factors ..cap alpha.. have been determined for /sup 6/Li and /sup 7/Li between lithium ions in methanol and complexed ions with a cryptand (2 sub(B), 2, 1) polymer. The /sup 6/Li was concentrated in the cryptand. The separation factors were compared with the values of other chemical exchange systems. The maximum enrichment factor obtained was epsilon = 0.047 +- 0.002. The figure is one of the greatest in the chemical exchange reactions without valence change and almost 10 times larger than the values of ion exchangers. The variation in ..cap alpha.. depending on the chemical species was small in the non-aqueous system. High enrichment of lithium isotopes was expected to be achievable by means of the chromatographic application of the cryptand (2 sub(B), 2, 1).

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Thin films of sodium montmorillonite clay and cationic polyacrylamide were grown on a polyethylene terephthalate film using layer-by-layer assembly. After 30 clay-polymer layers are deposited, with a thickness of 571 nm, the resulting transparent film has an oxygen transmission rate (OTR) below the detection limit of commercial instrumentation (< 0.005 cc/m{sup 2}/day/atm). This low OTR, which is unprecedented for a clay-filled polymer composite, is believed to be due to a brick wall nanostructure comprised of completely exfoliated clay in polymeric mortar. With an optical transparency greater than 90% and potential for microwaveability, this thin composite is a good candidate for foil replacement in food packaging and may also be useful for flexible electronics packaging.

International Nuclear Information System (INIS)

An effective method of enhancing charge injection and electroluminescence efficiency of polymer-based light emitting diode is introduced. Spin-coated films of poly (N-vinylcarbazole) blended with electron-transport material (Bu-PBD), laser dye (Coumarin6), and the typical supporting electrolyte (tetraethylammonium perchlorate; TEAP) were examined and it was found that the injection current and luminance of the light emitting diode doped with TEAP were enhanced dramatically after heat-treatment at 80 deg. C and appropriate biasing in an external electric field of 1.5x10"8 V/m at this temperature. The thermally stimulated current (TSC) was also measured to investigate the relaxation process of ionic space charges in the films. The relaxation times of ionic polarization were found to be related to the cation size of the electrolyte. And the relaxation time becomes long enough by the use of TEAP doping.

British Library Electronic Table of Contents (United Kingdom)

In this work, a highly-sensitive polymeric membrane ion selective electrode for determination of tetracycline was constructed by using molecularly imprinted polymer (MIP) particles as quasi-ionophore. The water-compatible MIP particles targeting tetracycline were synthesized with tetracycline as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2?-azobisisobutyronitrile as an initiator and lanthanum ion as a mediator. Benefited from the distinctive performance of the quasi-ionophore and the optimized composition of the membrane and the inner filling solution, the lower detection limit of the electrode was decreased to about 1 ? 10?8 mol/l. It exhibited a good electrode slope 59.8 mV/decade near the theoretical Nernstian one, ...

International Nuclear Information System (INIS)

Most surface-acoustic-wave and thin-film optical devices are made by the planar fabrication process. The exposure of the pattern in the polymer film is the first and most crucial step in ensuring desired device geometry, dimensional control, and freedom from pattern distortion. The methods of exposing the polymer film include: optical projection, conventional contact printing, conformable photomask contact printing, holographic recording, scanning electron beam lithography, projection electron lithography, and x-ray lithography. In this paper scanning electron beam lithography, conformable photomask contact printing, holographic recording, and x-ray lithography are discussed. In the last section, ion beam etching of relief structures is discussed.

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Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.